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Sample records for discharge impulse image

  1. Nonsputtering impulse magnetron discharge

    SciTech Connect

    Khodachenko, G. V.; Mozgrin, D. V.; Fetisov, I. K.; Stepanova, T. V.

    2012-01-15

    Experiments with quasi-steady high-current discharges in crossed E Multiplication-Sign B fields in various gases (Ar, N{sub 2}, H{sub 2}, and SF{sub 6}) and gas mixtures (Ar/SF{sub 6} and Ar/O{sub 2}) at pressures from 10{sup -3} to 5 Torr in discharge systems with different configurations of electric and magnetic fields revealed a specific type of stable low-voltage discharge that does not transform into an arc. This type of discharge came to be known as a high-current diffuse discharge and, later, a nonsputtering impulse magnetron discharge. This paper presents results from experimental studies of the plasma parameters (the electron temperature, the plasma density, and the temperature of ions and atoms of the plasma-forming gas) of a high-current low-pressure diffuse discharge in crossed E Multiplication-Sign B fields.

  2. Micropower impulse radar imaging

    SciTech Connect

    Hall, M.S.

    1995-11-01

    From designs developed at the Lawrence Livermore National Laboratory (LLNL) in radar and imaging technologies, there exists the potential for a variety of applications in both public and private sectors. Presently tests are being conducted for the detection of buried mines and the analysis of civil structures. These new systems use a patented ultra-wide band (impulse) radar technology known as Micropower Impulse Radar (GPR) imaging systems. LLNL has also developed signal processing software capable of producing 2-D and 3-D images of objects embedded in materials such as soil, wood and concrete. My assignment while at LLNL has focused on the testing of different radar configurations and applications, as well as assisting in the creation of computer algorithms which enable the radar to scan target areas of different geometeries.

  3. High power impulse magnetron sputtering discharge

    SciTech Connect

    Gudmundsson, J. T.; Brenning, N.; Lundin, D.; Helmersson, U.

    2012-05-15

    The high power impulse magnetron sputtering (HiPIMS) discharge is a recent addition to plasma based sputtering technology. In HiPIMS, high power is applied to the magnetron target in unipolar pulses at low duty cycle and low repetition frequency while keeping the average power about 2 orders of magnitude lower than the peak power. This results in a high plasma density, and high ionization fraction of the sputtered vapor, which allows better control of the film growth by controlling the energy and direction of the deposition species. This is a significant advantage over conventional dc magnetron sputtering where the sputtered vapor consists mainly of neutral species. The HiPIMS discharge is now an established ionized physical vapor deposition technique, which is easily scalable and has been successfully introduced into various industrial applications. The authors give an overview of the development of the HiPIMS discharge, and the underlying mechanisms that dictate the discharge properties. First, an introduction to the magnetron sputtering discharge and its various configurations and modifications is given. Then the development and properties of the high power pulsed power supply are discussed, followed by an overview of the measured plasma parameters in the HiPIMS discharge, the electron energy and density, the ion energy, ion flux and plasma composition, and a discussion on the deposition rate. Finally, some of the models that have been developed to gain understanding of the discharge processes are reviewed, including the phenomenological material pathway model, and the ionization region model.

  4. Discharge current modes of high power impulse magnetron sputtering

    SciTech Connect

    Wu, Zhongzhen Xiao, Shu; Ma, Zhengyong; Cui, Suihan; Ji, Shunping; Pan, Feng; Tian, Xiubo; Fu, Ricky K. Y.; Chu, Paul K.

    2015-09-15

    Based on the production and disappearance of ions and electrons in the high power impulse magnetron sputtering plasma near the target, the expression of the discharge current is derived. Depending on the slope, six possible modes are deduced for the discharge current and the feasibility of each mode is discussed. The discharge parameters and target properties are simplified into the discharge voltage, sputtering yield, and ionization energy which mainly affect the discharge plasma. The relationship between these factors and the discharge current modes is also investigated.

  5. Effect of Lightning Impulse Discharge on PVC Thin Film

    NASA Astrophysics Data System (ADS)

    Takamura, Norimitsu; Matsumoto, Takao; Nerome, Hazuki; Mishima, Kenji; Izawa, Yasuji; Hanai, Masahiro; Nishijima, Kiyoto

    2015-09-01

    Lightning damage to blades of wind turbine generators has been increasing in parallel with the recent increase in the installation of the generators. According to a paper, it is said that a large current produced by a lightning penetrates into the blades, the air temperature and pressure inside the blades increase, which causes destruction of the blades. In order to solve this problem, preventing lightning penetration into the blades and passing lightning only on the surface of the blades are required. Therefore, we undertook a basic research for finding out the mechanism of lightning penetration into the blades. In this study, as our original research for clarifying the above mechanism, we investigated the effect of lightning impulse discharge on some polyvinyl chloride thin films. A high voltage electrode and a ground electrode were set with 1.0 m separation. Each film was set at the midpoint of the electrodes and approximately 750 kV of only one positive lightning impulse voltage was applied to the electrodes. After discharge, the hole-, deformed- and tarnished- diameters of the films, formed by discharge, were measured using a microscope. The results suggest that the thickness and/or the volume resistivity of the films are deeply tied to destruction of the films by discharge.

  6. Plasma potential mapping of high power impulse magnetron sputtering discharges

    SciTech Connect

    Rauch, Albert; Mendelsberg, Rueben J.; Sanders, Jason M.; Anders, Andre

    2011-12-20

    Pulsed emissive probe techniques have been used to determine the plasma potential distribution of high power impulse magnetron sputtering (HiPIMS) discharges. An unbalanced magnetron with a niobium target in argon was investigated for pulse length of 100 μs at a pulse repetition rate of 100 Hz, giving a peak current of 170 A. The probe data were taken with a time resolution of 20 ns and a spatial resolution of 1 mm. It is shown that the local plasma potential varies greatly in space and time. The lowest potential was found over the target’s racetrack, gradually reaching anode potential (ground) several centimeters away from the target. The magnetic pre-sheath exhibits a funnel-shaped plasma potential resulting in an electric field which accelerates ions toward the racetrack. In certain regions and times, the potential exhibits weak local maxima which allow for ion acceleration to the substrate. Knowledge of the local E and static B fields lets us derive the electrons’ E×B drift velocity, which is about 105 m/s and shows structures in space and time.

  7. Microscopic degradation mechanism of polyimide film caused by surface discharge under bipolar continuous square impulse voltage

    NASA Astrophysics Data System (ADS)

    Luo, Yang; Wu, Guang-Ning; Liu, Ji-Wu; Peng, Jia; Gao, Guo-Qiang; Zhu, Guang-Ya; Wang, Peng; Cao, Kai-Jiang

    2014-02-01

    Polyimide (PI) film is an important type of insulating material used in inverter-fed motors. Partial discharge (PD) under a sequence of high-frequency square impulses is one of the key factors that lead to premature failures in insulation systems of inverter-fed motors. In order to explore the damage mechanism of PI film caused by discharge, an aging system of surface discharge under bipolar continuous square impulse voltage (BCSIV) is designed based on the ASTM 2275 01 standard and the electrical aging tests of PI film samples are performed above the partial discharge inception voltage (PDIV). The chemical bonds of PI polymer chains are analyzed through Fourier transform infrared spectroscopy (FTIR) and the dielectric properties of unaged and aged PI samples are investigated by LCR testers HIOKI 3532-50. Finally, the micro-morphology and micro-structure changes of PI film samples are observed through scanning electron microscopy (SEM). The results show that the physical and chemical effects of discharge cut off the chemical bonds of PI polymer chains. The fractures of ether bond (C—O—C) and imide ring (C—N—C) on the backbone of a PI polymer chain leads to the decrease of molecular weight, which results in the degradation of PI polymers and the generation of new chemical groups and materials, like carboxylic acid, ketone, aldehydes, etc. The variation of microscopic structure of PI polymers can change the orientation ability of polarizable units when the samples are under an AC electric field, which would cause the dielectric constant ɛ to increase and dielectric loss tan δ to decrease. The SEM images show that the degradation path of PI film is initiated from the surface and then gradually extends to the interior with continuous aging. The injection charge could result in the PI macromolecular chain degradation and increase the trap density in the PI polymer bulk.

  8. Characterization of high power impulse magnetron sputtering discharges

    NASA Astrophysics Data System (ADS)

    Hala, Matej

    Paper I: In the first paper, we present a new approach in the characterization of the high power pulsed magnetron sputtering (HiPIMS) discharge evolution—time- and species-resolved plasma imaging—employing a set of band-pass optical interference filters suitable for the isolation of the emission originating from different species populating the plasma. We demonstrate that the introduction of such filters can be used to distinguish different phases of the discharge, and to visualize numerous plasma effects including background gas excitations during the discharge ignition, gas shock waves, and expansion of metal-rich plasmas. In particular, the application of this technique is shown on the diagnostics of the 200 µs long non-reactive HiPIMS discharges using a Cr target. Paper II: In order to gain further information about the dynamics of reactive HiPIMS discharges, both fast plasma imaging and time- and space-resolved optical emission spectroscopy (OES) are used for a systematic investigation of the 200 µs long HiPIMS pulses operated in Ar, N2 and N 2/Ar mixtures and at various pressures. It is observed that the dense metal plasma created next to the target propagates in the reactor at a speed ranging from 0.7 to 3.5 km s-1, depending on the working gas composition and the pressure. In fact, it increases with higher N 2 concentration and with lower pressure. The visible form of the propagating plasma wave changes from a hemispherical shape in Ar to a drop-like shape extending far from the target with increasing N2 concentration, owing to the significant emission from molecular N2. Interestingly, the evidence of the target self-sputtering is found for all investigated conditions, including pure N2 atmosphere. Paper III: Here, we report on the time- and species-resolved plasma imaging analysis of the dynamics of the 200 µs long HiPIMS discharges above a Cr target ignited in pure O2. It is shown that the discharge emission is dominated solely by neutral and

  9. Impulse Magnetic Fields Generated by Electrostatic Discharges in Protoplanetary Nebulae

    NASA Technical Reports Server (NTRS)

    Tunyi, I.; Guba, P.; Roth, L. E.; Timko, M.

    2002-01-01

    We examine quantitative aspects associated with the hypothesis of nebular lightnings as a source of impulse magnetic fields. Our findings support our previous accretion model in which a presence of impulse magnetic fields was of a key necessity. Additional information is contained in the original extended abstract.

  10. Transthoracic Cardiac Acoustic Radiation Force Impulse Imaging

    NASA Astrophysics Data System (ADS)

    Bradway, David Pierson

    This dissertation investigates the feasibility of a real-time transthoracic Acoustic Radiation Force Impulse (ARFI) imaging system to measure myocardial function non-invasively in clinical setting. Heart failure is an important cardiovascular disease and contributes to the leading cause of death for developed countries. Patients exhibiting heart failure with a low left ventricular ejection fraction (LVEF) can often be identified by clinicians, but patients with preserved LVEF might be undetected if they do not exhibit other signs and symptoms of heart failure. These cases motivate development of transthoracic ARFI imaging to aid the early diagnosis of the structural and functional heart abnormalities leading to heart failure. M-Mode ARFI imaging utilizes ultrasonic radiation force to displace tissue several micrometers in the direction of wave propagation. Conventional ultrasound tracks the response of the tissue to the force. This measurement is repeated rapidly at a location through the cardiac cycle, measuring timing and relative changes in myocardial stiffness. ARFI imaging was previously shown capable of measuring myocardial properties and function via invasive open-chest and intracardiac approaches. The prototype imaging system described in this dissertation is capable of rapid acquisition, processing, and display of ARFI images and shear wave elasticity imaging (SWEI) movies. Also presented is a rigorous safety analysis, including finite element method (FEM) simulations of tissue heating, hydrophone intensity and mechanical index (MI) measurements, and thermocouple transducer face heating measurements. For the pulse sequences used in later animal and clinical studies, results from the safety analysis indicates that transthoracic ARFI imaging can be safely applied at rates and levels realizable on the prototype ARFI imaging system. Preliminary data are presented from in vivo trials studying changes in myocardial stiffness occurring under normal and abnormal

  11. On the electron energy in the high power impulse magnetron sputtering discharge

    SciTech Connect

    Gudmundsson, J. T.; Sigurjonsson, P.; Larsson, P.; Lundin, D.; Helmersson, U.

    2009-06-15

    The temporal variation of the electron energy distribution function (EEDF) was measured with a Langmuir probe in a high power impulse magnetron sputtering (HiPIMS) discharge at 3 and 20 mTorr pressures. In the HiPIMS discharge a high power pulse is applied to a planar magnetron giving a high electron density and highly ionized sputtered vapor. The measured EEDF is Maxwellian-like during the pulse; it is broader for lower discharge pressure and it becomes narrower as the pulse progresses. This indicates that the plasma cools as the pulse progresses, probably due to high metal content of the discharge.

  12. Discharge Physics of High Power Impulse Magnetron Sputtering

    SciTech Connect

    Anders, Andre

    2010-10-13

    High power impulse magnetron sputtering (HIPIMS) is pulsed sputtering where the peak power exceeds the time-averaged power by typically two orders of magnitude. The peak power density, averaged over the target area, can reach or exceed 107 W/m2, leading to plasma conditions that make ionization of the sputtered atoms very likely. A brief review of HIPIMS operation is given in a tutorial manner, illustrated by some original data related to the self-sputtering of niobium in argon and krypton. Emphasis is put on the current-voltage-time relationships near the threshold of self-sputtering runaway. The great variety of current pulse shapes delivers clues on the very strong gas rarefaction, self-sputtering runaway conditions, and the stopping of runaway due to the evolution of atom ionization and ion return probabilities as the gas plasma is replaced by metal plasma. The discussions are completed by considering instabilities and the special case of ?gasless? self-sputtering.

  13. Electron density measurements in a photoinitiated, impulse-enhanced, electrically excited laser gas discharge

    NASA Astrophysics Data System (ADS)

    Seguin, V. A.; Seguin, H. J. J.; Capjack, C. E.; Nikumb, S. K.

    1986-11-01

    Measurements of the electron density within a photo-initiated, impulse-enhanced, electrically excited (PIE) laser gas discharge are presented. Ion current measurements were made using a single Langmuir electrostatic probe positioned within the laser discharge volume. Calculations of the electron density were made utilizing a thick-sheath analysis. The results indicate that the electron density increases by two orders of magnitude as the pulser power level is increased. In addition, the electron density was observed to decrease markedly as the dc discharge current was increased.

  14. Are the argon metastables important in high power impulse magnetron sputtering discharges?

    SciTech Connect

    Gudmundsson, J. T.; Lundin, D.; Minea, T. M.; Stancu, G. D.; Brenning, N.

    2015-11-15

    We use an ionization region model to explore the ionization processes in the high power impulse magnetron sputtering (HiPIMS) discharge in argon with a titanium target. In conventional dc magnetron sputtering (dcMS), stepwise ionization can be an important route for ionization of the argon gas. However, in the HiPIMS discharge stepwise ionization is found to be negligible during the breakdown phase of the HiPIMS pulse and becomes significant (but never dominating) only later in the pulse. For the sputtered species, Penning ionization can be a significant ionization mechanism in the dcMS discharges, while in the HiPIMS discharge Penning ionization is always negligible as compared to electron impact ionization. The main reasons for these differences are a higher plasma density in the HiPIMS discharge, and a higher electron temperature. Furthermore, we explore the ionization fraction and the ionized flux fraction of the sputtered vapor and compare with recent experimental work.

  15. Quenching electron runaway in positive high-voltage-impulse discharges in air by laser filaments.

    PubMed

    Eto, S; Zhidkov, A; Oishi, Y; Miki, M; Fujii, T

    2012-03-15

    Strong hard (ε>100 keV) x rays being observed from impulse atmospheric discharges with maximal voltages from U=0.5 to 0.9 MV just before the breakdown were completely stopped with the use of femtosecond-laser-filament plasma. Runaway electrons generating such x rays and being estimated to achieve their maximal energy, ε~U, near the positive electrode disappear if a laser filament plasma is ignited perpendicularly to the runaway near the positive electrode. A preheating mechanism for formation of the electron runaway in air is proposed.

  16. Computational modelling of discharges within the impulse plasma deposition accelerator with a gas valve

    NASA Astrophysics Data System (ADS)

    Rabiński, Marek; Choduń, Rafał; Nowakowska-Langier, Katarzyna; Zdunek, Krzysztof

    2014-05-01

    The paper presents computational studies of working medium dynamics during the impulse plasma deposition (IPD) process when the electric discharge in an interelectrode region is initiated by a gas introduced through a fast-acting valve. During the computational simulations the influence of different discharge parameters on the plasma dynamics was studied. The optimization of the device includes the calculation of the current sheath movement and the sensibility analysis of its dynamics to geometrical and operational parameters. It was found that gas injection can be considered as a useful tool in optimization of the coatings obtained with the IPD technique. Computer simulation results indicate the direction of changes in the development and application of the analysed surface engineering method.

  17. Current-voltage-time characteristics of the reactive Ar/N{sub 2} high power impulse magnetron sputtering discharge

    SciTech Connect

    Magnus, F.; Sveinsson, O. B.; Olafsson, S.; Gudmundsson, J. T.

    2011-10-15

    The discharge current and voltage waveforms have been measured in a reactive high power impulse magnetron sputtering (HiPIMS) Ar/N{sub 2} discharge with a Ti target for 400 {mu}s long pulses. We observe that the current waveform in the reactive Ar/N{sub 2} HiPIMS discharge is highly dependent on the pulse repetition frequency, unlike the non-reactive Ar discharge. The current is found to increase significantly as the frequency is lowered. This is attributed to an increase in the secondary electron emission yield during the self-sputtering phase, when the nitride forms on the target at low frequencies. In addition, self-sputtering runaway occurs at lower discharge voltages when nitrogen is added to the discharge. This illustrates the crucial role of self-sputtering in the behavior of the reactive HiPIMS discharge.

  18. Impulse Three Phase Power Supply Used for a Gliding Plasma Discharge

    NASA Astrophysics Data System (ADS)

    Salazar-Torres, J. A.; Pacheco-Sotelo, J.; Valdivia-Barrientos, R.; Pacheco-Pacheco, M.; Ramos-Flores, F.; Soria-Arguello, G.; Ibañez-Olvera, M.

    2015-03-01

    Power sources used for generating plasma have different configurations depending on the particular application; the aim here comprises the maximum energy transfer to the plasma discharge reaching. This work shows the performance and versatility of a simple impulse phase power source, applied to gliding arc plasma discharge. It is capable of changing the operating frequency from 5 kHz up to 150 kHz and the duty cycle from 1% to 33% in all three phases, each one connected to three divergent tungsten electrodes. This allows a soft start plasma ignition until the full load is reached. This converter uses a sequential logic circuits composed by flip-flops, gates drivers, IGBT's and high voltage ferrite transformers. These features facilitate the maximum energy transfer to the plasma without using more complex electronic structures. The effect of frequency, duty cycle, voltage and current wave form signals is here described. This power supply has the adaptability to work whit different type of gas such as Argon, Helium, Air and Nitrogen. A Matlab Simulink simulation validates the experimental results. The main features and advantages of this configuration are also defined.

  19. Investigation of ionized metal flux in enhanced high power impulse magnetron sputtering discharges

    SciTech Connect

    Stranak, Vitezslav; Hubicka, Zdenek; Cada, Martin; Drache, Steffen; Hippler, Rainer; Tichy, Milan

    2014-04-21

    The metal ionized flux fraction and production of double charged metal ions Me{sup 2+} of different materials (Al, Cu, Fe, Ti) by High Power Impulse Magnetron Sputtering (HiPIMS) operated with and without a pre-ionization assistance is compared in the paper. The Electron Cyclotron Wave Resonance (ECWR) discharge was employed as the pre-ionization agent providing a seed of charge in the idle time of HiPIMS pulses. A modified grid-free biased quartz crystal microbalance was used to estimate the metal ionized flux fraction ξ. The energy-resolved mass spectrometry served as a complementary method to distinguish particular ion contributions to the total ionized flux onto the substrate. The ratio between densities of doubly Me{sup 2+} and singly Me{sup +} charged metal ions was determined. It is shown that ECWR assistance enhances Me{sup 2+} production with respect of absorbed rf-power. The ECWR discharge also increases the metal ionized flux fraction of about 30% especially in the region of lower pressures. Further, the suppression of the gas rarefaction effect due to enhanced secondary electron emission of Me{sup 2+} was observed.

  20. Clustered impulse noise removal from color images with spatially connected rank filtering

    NASA Astrophysics Data System (ADS)

    Ruchay, Alexey; Kober, Vitaly

    2016-09-01

    This paper deals with impulse noise removal from color images. The proposed noise removal algorithm employs two classical approaches for color image denoising; that is, detection of corrupted pixels and removal of the detected noise by means of local rank filtering. With the help of computer simulation we show that the proposed algorithm can effectively remove impulse noise and clustered impulse noise. The performance of the proposed algorithm is compared in terms of image restoration metrics with that of common successful algorithms.

  1. Spatial and temporal evolution of ion energies in high power impulse magnetron sputtering plasma discharge

    NASA Astrophysics Data System (ADS)

    Hecimovic, A.; Ehiasarian, A. P.

    2010-09-01

    High power impulse magnetron sputtering (HIPIMS) is a novel deposition technology successfully implemented on full scale industrial machines. HIPIMS utilizes short pulses of high power delivered to the target in order to generate high amount of metal ions. The life-span of ions between the pulses and their energy distribution could strongly influence the properties and characteristics of the deposited coating. In modern industrial coating machines the sample rotates on a substrate holder and changes its position and distance with regard to the magnetron. Time resolved measurements of the ion energy distribution function (IEDF) at different distances from the magnetron have been performed to investigate the temporal evolution of ions at various distances from target. The measurements were performed using two pressures, 1 and 3 Pa to investigate the influence of working gas pressure on IEDF. Plasma sampling energy-resolved mass spectroscopy was used to measure the IEDF of Ti1+, Ti2+, Ar1+, and Ar2+ ions in HIPIMS plasma discharge with titanium (Ti) target in Ar atmosphere. The measurements were done over a full pulse period and the distance between the magnetron and the orifice of the mass spectrometer was changed from 25 to 215 mm.

  2. An ionization region model of the reactive Ar/O2 high power impulse magnetron sputtering discharge

    NASA Astrophysics Data System (ADS)

    Gudmundsson, Jon Tomas; Lundin, Daniel; Brenning, Nils; Raadu, Michel A.; Huo, Chunqing; Minea, Tiberiu

    2016-09-01

    A reactive ionization region model (R-IRM) is developed to describe the reactive Ar/O2 high power impulse magnetron sputtering (HiPIMS) discharge with titanium target. We compare the discharge properties when the discharge is operated in the two well established operating modes, the metal mode and the poisoned mode. Experimentally, it is found that in the metal mode the discharge current waveform displays a typical non-reactive evolution, while in the poisoned mode the discharge current waveform becomes distinctly triangular and the current increases significantly. Using the R-IRM we find that when the discharge is operated in the metal mode Ar+ and Ti+-ions contribute most significantly (roughly equal amounts) to the discharge current while in the poisoned mode the Ar+-ions contribute most significantly to the discharge current while the contribution of O+-ions and secondary electron emission is much smaller. Furthermore, we find that recycling of ionized atoms coming from the target are required for the current generation in both modes of operation. In the metal mode self-sputter recycling dominates and in the poisoned mode working gas recycling dominates, and it is concluded that the dominating type of recycling determines the discharge current waveform.

  3. An ionization region model of the reactive Ar/O2 high power impulse magnetron sputtering discharge

    NASA Astrophysics Data System (ADS)

    Gudmundsson, J. T.; Lundin, D.; Brenning, N.; Raadu, M. A.; Huo, Chunqing; Minea, T. M.

    2016-12-01

    A new reactive ionization region model (R-IRM) is developed to describe the reactive Ar/O2 high power impulse magnetron sputtering (HiPIMS) discharge with a titanium target. It is then applied to study the temporal behavior of the discharge plasma parameters such as electron density, the neutral and ion composition, the ionization fraction of the sputtered vapor, the oxygen dissociation fraction, and the composition of the discharge current. We study and compare the discharge properties when the discharge is operated in the two well established operating modes, the metal mode and the poisoned mode. Experimentally, it is found that in the metal mode the discharge current waveform displays a typical non-reactive evolution, while in the poisoned mode the discharge current waveform becomes distinctly triangular and the current increases significantly. Using the R-IRM we explore the current increase and find that when the discharge is operated in the metal mode Ar+ and Ti+ -ions contribute most significantly (roughly equal amounts) to the discharge current while in the poisoned mode the Ar+ -ions contribute most significantly to the discharge current and the contribution of O+ -ions, Ti+ -ions, and secondary electron emission is much smaller. Furthermore, we find that recycling of atoms coming from the target, that are subsequently ionized, is required for the current generation in both modes of operation. From the R-IRM results it is found that in the metal mode self-sputter recycling dominates and in the poisoned mode working gas recycling dominates. We also show that working gas recycling can lead to very high discharge currents but never to a runaway. It is concluded that the dominating type of recycling determines the discharge current waveform.

  4. Time-lag properties of corona streamer discharges between impulse sphere and dc needle electrodes under atmospheric air conditions.

    PubMed

    Okano, Daisuke

    2013-02-01

    In this study of corona streamer discharges from an impulse generator using a dc power supply, the relationship of the discharge time-lag with the dc bias voltage between the sphere-to-needle electrodes under atmospheric conditions is investigated. Devices utilizing corona discharges have been used to purify air or water, destroy bacteria, and to remove undesirable substances, and in order to achieve fast response times and high power efficiencies in such devices, it is important to minimize the time-lag of the corona discharge. Our experimental results show that (a) the discharge path of a negatively biased needle electrode will be straighter than that of a positively biased needle and (b) the discharge threshold voltage in both the positive and the negative needle electrodes is nearly equal to 33 kV. By expressing the discharge voltage as a power function of time-lag, the extent of corona generation can be quantitatively specified using the exponent of this power function. The observed behavior of a corona streamer discharge between the negative spherical and the positive needle electrodes indicates that the largest power exponent is associated with the shortest time-lag, owing to the reduction in the statistical time-lag in the absence of a formative time-lag.

  5. Time-lag properties of corona streamer discharges between impulse sphere and dc needle electrodes under atmospheric air conditions

    NASA Astrophysics Data System (ADS)

    Okano, Daisuke

    2013-02-01

    In this study of corona streamer discharges from an impulse generator using a dc power supply, the relationship of the discharge time-lag with the dc bias voltage between the sphere-to-needle electrodes under atmospheric conditions is investigated. Devices utilizing corona discharges have been used to purify air or water, destroy bacteria, and to remove undesirable substances, and in order to achieve fast response times and high power efficiencies in such devices, it is important to minimize the time-lag of the corona discharge. Our experimental results show that (a) the discharge path of a negatively biased needle electrode will be straighter than that of a positively biased needle and (b) the discharge threshold voltage in both the positive and the negative needle electrodes is nearly equal to 33 kV. By expressing the discharge voltage as a power function of time-lag, the extent of corona generation can be quantitatively specified using the exponent of this power function. The observed behavior of a corona streamer discharge between the negative spherical and the positive needle electrodes indicates that the largest power exponent is associated with the shortest time-lag, owing to the reduction in the statistical time-lag in the absence of a formative time-lag.

  6. Free segmentation in rendered 3D images through synthetic impulse response in integral imaging

    NASA Astrophysics Data System (ADS)

    Martínez-Corral, M.; Llavador, A.; Sánchez-Ortiga, E.; Saavedra, G.; Javidi, B.

    2016-06-01

    Integral Imaging is a technique that has the capability of providing not only the spatial, but also the angular information of three-dimensional (3D) scenes. Some important applications are the 3D display and digital post-processing as for example, depth-reconstruction from integral images. In this contribution we propose a new reconstruction method that takes into account the integral image and a simplified version of the impulse response function (IRF) of the integral imaging (InI) system to perform a two-dimensional (2D) deconvolution. The IRF of an InI system has a periodic structure that depends directly on the axial position of the object. Considering different periods of the IRFs we recover by deconvolution the depth information of the 3D scene. An advantage of our method is that it is possible to obtain nonconventional reconstructions by considering alternative synthetic impulse responses. Our experiments show the feasibility of the proposed method.

  7. Identifying Vulnerable Plaques with Acoustic Radiation Force Impulse Imaging

    NASA Astrophysics Data System (ADS)

    Doherty, Joshua Ryan

    The rupture of arterial plaques is the most common cause of ischemic complications including stroke, the fourth leading cause of death and number one cause of long term disability in the United States. Unfortunately, because conventional diagnostic tools fail to identify plaques that confer the highest risk, often a disabling stroke and/or sudden death is the first sign of disease. A diagnostic method capable of characterizing plaque vulnerability would likely enhance the predictive ability and ultimately the treatment of stroke before the onset of clinical events. This dissertation evaluates the hypothesis that Acoustic Radiation Force Impulse (ARFI) imaging can noninvasively identify lipid regions, that have been shown to increase a plaque's propensity to rupture, within carotid artery plaques in vivo. The work detailed herein describes development efforts and results from simulations and experiments that were performed to evaluate this hypothesis. To first demonstrate feasibility and evaluate potential safety concerns, finite- element method simulations are used to model the response of carotid artery plaques to an acoustic radiation force excitation. Lipid pool visualization is shown to vary as a function of lipid pool geometry and stiffness. A comparison of the resulting Von Mises stresses indicates that stresses induced by an ARFI excitation are three orders of magnitude lower than those induced by blood pressure. This thesis also presents the development of a novel pulse inversion harmonic tracking method to reduce clutter-imposed errors in ultrasound-based tissue displacement estimates. This method is validated in phantoms and was found to reduce bias and jitter displacement errors for a marked improvement in image quality in vivo. Lastly, this dissertation presents results from a preliminary in vivo study that compares ARFI imaging derived plaque stiffness with spatially registered composition determined by a Magnetic Resonance Imaging (MRI) gold standard

  8. Impulse radar imaging system for concealed object detection

    NASA Astrophysics Data System (ADS)

    Podd, F. J. W.; David, M.; Iqbal, G.; Hussain, F.; Morris, D.; Osakue, E.; Yeow, Y.; Zahir, S.; Armitage, D. W.; Peyton, A. J.

    2013-10-01

    Electromagnetic systems for imaging concealed objects at checkpoints typically employ radiation at millimetre and terahertz frequencies. These systems have been shown to be effective and provide a sufficiently high resolution image. However there are difficulties and current electromagnetic systems have limitations particularly in accurately differentiating between threat and innocuous objects based on shape, surface emissivity or reflectivity, which are indicative parameters. In addition, water has a high absorption coefficient at millimetre wavelength and terahertz frequencies, which makes it more difficult for these frequencies to image through thick damp clothing. This paper considers the potential of using ultra wideband (UWB) in the low gigahertz range. The application of this frequency band to security screening appears to be a relatively new field. The business case for implementing the UWB system has been made financially viable by the recent availability of low-cost integrated circuits operating at these frequencies. Although designed for the communication sector, these devices can perform the required UWB radar measurements as well. This paper reports the implementation of a 2 to 5 GHz bandwidth linear array scanner. The paper describes the design and fabrication of transmitter and receiver antenna arrays whose individual elements are a type of antipodal Vivaldi antenna. The antenna's frequency and angular response were simulated in CST Microwave Studio and compared with laboratory measurements. The data pre-processing methods of background subtraction and deconvolution are implemented to improve the image quality. The background subtraction method uses a reference dataset to remove antenna crosstalk and room reflections from the dataset. The deconvolution method uses a Wiener filter to "sharpen" the returned echoes which improves the resolution of the reconstructed image. The filter uses an impulse response reference dataset and a signal

  9. Image modulation in corona discharge photography.

    PubMed

    Pehek, J O; Kyler, H J; Faust, D L

    1976-10-15

    Photographic images obtained by the Kirlian technique are principally a record of corona activity during an exposure interval. Most of the variations in the images of the corona of a living subject who is in contact with the photographic film can be accounted for by the presence of moisture on or within the subject's surface. During exposure, moisture is transferred from the subject to the emulsion surface of the photographic film and causes an alteration of the electric charge pattern on the film, hence the electric field at the surface of the subject. As a result, large variations in the density of corona images, corona streamer trajectories, and image coloration can be brought about. The radial extent of corona images--that is, the range of corona streamers--is an inverse function of the resistance in the circuit formed by the high-voltage supply, the subject, and the film-electrode configuration. This is because the voltage at which corona is initiated is dependent on the rate of rise of the voltage impressed between the subject and the electrode, and the rate of rise is governed by the applied voltage waveform and the voltage drop across the resistance. The range of streamers is proportional to the corona onset voltage. However, we have not seen any influence of large changes in skin resistance on streamer range. Presumably, this is due to the shunting effect of skin capacitance. In general, the photographic response to moisture suggests that corona discharge photography may be useful in the detection and quantification of moisture in animate and inanimate specimens through the orderly modulation of the image due to various levels of moisture.

  10. Development of a Specific Impulse Balance for a Pulsed Capillary Discharge (Preprint)

    DTIC Science & Technology

    2008-06-13

    thrust stand [rad/s] I. Introduction A capillary discharge based coaxial , electrothermal pulsed plasma thruster (PPT) is currently under...20-23 July 2008. 14. ABSTRACT A capillary discharge based pulsed plasma thruster is currently under development at the Air Force Research...Edwards AFB, CA 93524 A capillary discharge based pulsed plasma thruster is currently under development at the Air Force Research Laboratory. A

  11. Removing impulse bursts from images by training-based soft morphological filtering

    NASA Astrophysics Data System (ADS)

    Koivisto, Pertti T.; Astola, Jaakko T.; Lukin, Vladimir V.; Melnik, Vladimir P.; Tsymbal, Oleg V.

    2001-08-01

    The characteristics of impulse bursts in radar images are analyzed and a model for this noise is proposed. The model also takes into consideration the multiplicative noise present in radar images. As a case study, soft morphological filters utilizing a training-based optimization scheme are used for the noise removal. Different approaches for the training are discussed. It is shown that the methods used can provide an effective removal of impulse bursts. At the same time the multiplicative noise in images is also suppressed together with god edge and detail preservation. Numerical simulation results as well as examples of real radar images are presented.

  12. Liver reserve function assessment by acoustic radiation force impulse imaging

    PubMed Central

    Sun, Xiao-Lan; Liang, Li-Wei; Cao, Hui; Men, Qiong; Hou, Ke-Zhu; Chen, Zhen; Zhao, Ya-E

    2015-01-01

    AIM: To evaluate the utility of liver reserve function by acoustic radiation force impulse (ARFI) imaging in patients with liver tumors. METHODS: Seventy-six patients with liver tumors were enrolled in this study. Serum biochemical indexes, such as aminotransferase (ALT), aspartate aminotransferase (AST), serum albumin (ALB), total bilirubin (T-Bil), and other indicators were observed. Liver stiffness (LS) was measured by ARFI imaging, measurements were repeated 10 times, and the average value of the results was taken as the final LS value. Indocyanine green (ICG) retention was performed, and ICG-K and ICG-R15 were recorded. Child-Pugh (CP) scores were carried out based on patient’s preoperative biochemical tests and physical condition. Correlations among CP scores, ICG-R15, ICG-K and LS values were observed and analyzed using either the Pearson correlation coefficient or the Spearman rank correlation coefficient. Kruskal-Wallis test was used to compare LS values of CP scores, and the receiver-operator characteristic (ROC) curve was used to analyze liver reserve function assessment accuracy. RESULTS: LS in the ICG-R15 10%-20% group was significantly higher than in the ICG-R15 < 10% group; and the difference was statistically significant (2.19 ± 0.27 vs 1.59 ± 0.32, P < 0.01). LS in the ICG-R15 > 20% group was significantly higher than in the ICG-R15 < 10% group; and the difference was statistically significant (2.92 ± 0.29 vs 1.59 ± 0.32, P < 0.01). The LS value in patients with CP class A was lower than in patients with CP class B (1.57 ± 0.34 vs 1.86 ± 0.27, P < 0.05), while the LS value in patients with CP class B was lower than in patients with CP class C (1.86 ± 0.27 vs 2.47 ± 0.33, P < 0.01). LS was positively correlated with ICG-R15 (r = 0.617, P < 0.01) and CP score (r = 0.772, P < 0.01). Meanwhile, LS was negatively correlated with ICG-K (r = -0.673, P < 0.01). AST, ALT and T-Bil were positively correlated with LS, while ALB was negatively

  13. Performance characteristics of quasi-steady MPD discharges. [spacecraft plasma propulsion thrust efficiency and specific impulse

    NASA Technical Reports Server (NTRS)

    Rudolph, L. K.; Jahn, R. G.; Clark, K. E.; Von Jaskowsky, W. F.

    1976-01-01

    The onset of voltage fluctuations in a multi-megawatt quasi-steady MPD accelerator, indicative of increased cathode ablation and a consequent degradation of performance, is found to be a function of cathode size. With longer cathodes, this onset shifts to substantially higher powers per unit mass flow and the plasma exhaust velocity can be increased to values previously thought inaccessible to accelerators of this class. Centerline velocities up to 30 km/sec have been measured in argon, which for the observed exhaust profiles translate into specific impulses up to 2400 sec and corresponding thrust efficiencies above 30%.

  14. Suppression of impulse noise in medical images with the use of Fuzzy Adaptive Median Filter.

    PubMed

    Toprak, Abdullah; Güler, Inan

    2006-12-01

    A new rule based fuzzy filter for removal of highly impulse noise, called Rule Based Fuzzy Adaptive Median (RBFAM) Filter, is aimed to be discussed in this paper. The RBFAM filter is an improved version of Adaptive Median Filter (AMF) and is presented in the aim of noise reduction of images corrupted with additive impulse noise. The filter has three stages. Two of those stages are fuzzy rule based and last stage is based on standard median and adaptive median filter. The proposed filter can preserve image details better then AMF while suppressing additive salt & pepper or impulse type noise. In this paper, we placed our preference on bell-shaped membership function instead of triangular membership function in order to observe better results. Experimental results indicates that the proposed filter is improvable with increased fuzzy rules to reduce more noise corrupted images and to remove salt and pepper noise in a more effective way than what AMF filter does.

  15. Volume-surface barrier discharge in dried air in three-electrode system fed by impulse high voltage with nanosecond rise time

    NASA Astrophysics Data System (ADS)

    Malashin, Maxim; Rebrov, Igor; Nebogatkin, Sergey; Sokolova, Marina; Nikitin, Alexey; Voevodin, Vadim; Krivov, Sergey

    2016-08-01

    Results of experimental investigation of a volume-surface barrier discharge in a three-electrode system under periodic impulse voltage applied to the surface discharge (SD) electrodes and a d.c. potential applied to an additional third electrode are presented. It is shown that there is a strong influence of polarity and amplitude of the d.c. potential on the direct current "extracted" out of the surface discharge plasma layer by electric field of the third electrode. The amount of charged positive species that constitute the "extracted" current prevails under positive impulse voltage for low values of the negative d.c. potential of the third electrode. The amount of negative species prevails with higher values of the positive d.c. positive of the third electrode. Contribution to the topical issue "6th Central European Symposium on Plasma Chemistry (CESPC-6)", edited by Nicolas Gherardi, Ester Marotta and Cristina Paradisi

  16. The Image of Teachers: The Perception of Others as Impulses for the Professionalisation of Teaching

    ERIC Educational Resources Information Center

    Grunder, Hans-Ulrich

    2016-01-01

    This article describes the images of teachers as constructs of a public interest in education and schools. It uses the portrayals of teachers as a productive impulse to reflect on what the professionalisation of teaching practice in schools and classrooms could imply, in particular focusing on the characteristics of accomplished teachers and poor…

  17. Dielectric barrier discharge image processing by Photoshop

    NASA Astrophysics Data System (ADS)

    Dong, Lifang; Li, Xuechen; Yin, Zengqian; Zhang, Qingli

    2001-09-01

    In this paper, the filamentary pattern of dielectric barrier discharge has been processed by using Photoshop, the coordinates of each filament can also be obtained. By using Photoshop two different ways have been used to analyze the spatial order of the pattern formation in dielectric barrier discharge. The results show that the distance of the neighbor filaments at U equals 14 kV and d equals 0.9 mm is about 1.8 mm. In the scope of the experimental error, the results from the two different methods are similar.

  18. On the efficiency of techniques for the reduction of impulsive noise in astronomical images

    NASA Astrophysics Data System (ADS)

    Popowicz, A.; Kurek, A. R.; Blachowicz, T.; Orlov, V.; Smolka, B.

    2016-12-01

    The impulsive noise in astronomical images originates from various sources. It develops as a result of thermal generation in pixels or the collision of cosmic rays with an image sensor, or it may be induced by high read-out voltage in an electron-multiplying CCD (EMCCD). It is usually efficiently removed by employing the dark frames or by averaging several exposures. Unfortunately, there are some circumstances when either the observed objects or positions of impulsive pixels evolve and, therefore, each image obtained has to be filtered independently. In this article we present an overview of impulsive noise filtering methods and compare their efficiency for astronomical image enhancement. The set of noise templates employed consists of dark frames obtained from CCD and EMCCD cameras working on the ground and in space. The experiments, conducted on synthetic and real images, allowed for drawing numerous conclusions about the usefulness of several filtering methods for various: (1) widths of stellar profiles, (2) signal-to-noise ratios, (3) noise distributions and (4) applied imaging techniques. The results of this evaluation are especially valuable for selecting the most efficient filtering schema in astronomical image-processing pipelines.

  19. Imaging Impulsivity in Parkinson's Disease and the Contribution of the Subthalamic Nucleus

    PubMed Central

    Ray, Nicola; Antonelli, Francesca; Strafella, Antonio P.

    2011-01-01

    Taking risks is a natural human response, but, in some, risk taking is compulsive and may be detrimental. The subthalamic nucleus (STN) is thought to play a large role in our ability to inhibit responses. Differences between individuals' ability to inhibit inappropriate responses may underlie both the normal variation in trait impulsivity in the healthy population, as well as the pathological compulsions experienced by those with impulse control disorders (ICDs). Thus, we review the role of the STN in response inhibition, with a particular focus on studies employing imaging methodology. We also review the latest evidence that disruption of the function of the STN by deep brain stimulation in patients with Parkinson's disease can increase impulsivity. PMID:21765999

  20. High-speed imaging system for observation of discharge phenomena

    NASA Astrophysics Data System (ADS)

    Tanabe, R.; Kusano, H.; Ito, Y.

    2008-11-01

    A thin metal electrode tip instantly changes its shape into a sphere or a needlelike shape in a single electrical discharge of high current. These changes occur within several hundred microseconds. To observe these high-speed phenomena in a single discharge, an imaging system using a high-speed video camera and a high repetition rate pulse laser was constructed. A nanosecond laser, the wavelength of which was 532 nm, was used as the illuminating source of a newly developed high-speed video camera, HPV-1. The time resolution of our system was determined by the laser pulse width and was about 80 nanoseconds. The system can take one hundred pictures at 16- or 64-microsecond intervals in a single discharge event. A band-pass filter at 532 nm was placed in front of the camera to block the emission of the discharge arc at other wavelengths. Therefore, clear images of the electrode were recorded even during the discharge. If the laser was not used, only images of plasma during discharge and thermal radiation from the electrode after discharge were observed. These results demonstrate that the combination of a high repetition rate and a short pulse laser with a high speed video camera provides a unique and powerful method for high speed imaging.

  1. Spectroscopic imaging of self-organization in high power impulse magnetron sputtering plasmas

    SciTech Connect

    Centre for Quantum Technologies, National University of Singapore, 3 Science Drive 2, 117543 Singapore, Singapore; Andersson, Joakim; Ni, Pavel; Anders, Andre

    2013-07-17

    Excitation and ionization conditions in traveling ionization zones of high power impulse magnetron sputtering plasmas were investigated using fast camera imaging through interference filters. The images, taken in end-on and side on views using light of selected gas and target atom and ion spectral lines, suggest that ionization zones are regions of enhanced densities of electrons, and excited atoms and ions. Excited atoms and ions of the target material (Al) are strongly concentrated near the target surface. Images from the highest excitation energies exhibit the most localized regions, suggesting localized Ohmic heating consistent with double layer formation.

  2. Acoustic radiation force impulse imaging for evaluation of renal parenchyma elasticity in diabetic nephropathy.

    PubMed

    Goya, Cemil; Kilinc, Faruk; Hamidi, Cihad; Yavuz, Alpaslan; Yildirim, Yasar; Cetincakmak, Mehmet Guli; Hattapoglu, Salih

    2015-02-01

    OBJECTIVE. The goal of this study is to evaluate the changes in the elasticity of the renal parenchyma in diabetic nephropathy using acoustic radiation force impulse imaging. SUBJECTS AND METHODS. The study included 281 healthy volunteers and 114 patients with diabetic nephropathy. In healthy volunteers, the kidney elasticity was assessed quantitatively by measuring the shear-wave velocity using acoustic radiation force impulse imaging based on age, body mass index, and sex. The changes in the renal elasticity were compared between the different stages of diabetic nephropathy and the healthy control group. RESULTS. In healthy volunteers, there was a statistically significant correlation between the shear-wave velocity values and age and sex. The shear-wave velocity values for the kidneys were 2.87, 3.14, 2.95, 2.68, and 2.55 m/s in patients with stage 1, 2, 3, 4, and 5 diabetic nephropathy, respectively, compared with 2.35 m/s for healthy control subjects. Acoustic radiation force impulse imaging was able to distinguish between the different diabetic nephropathy stages (except for stage 5) in the kidneys. The threshold value for predicting diabetic nephropathy was 2.43 m/s (sensitivity, 84.1%; specificity, 67.3%; positive predictive value, 93.1%; negative predictive value 50.8%; accuracy, 72.1%; positive likelihood ratio, 2.5; and negative likelihood ratio, 0.23). CONCLUSION. Acoustic radiation force impulse imaging could be used for the evaluation of the renal elasticity changes that are due to secondary structural and functional changes in diabetic nephropathy.

  3. Adaptive two-pass rank order filter to remove impulse noise in highly corrupted images.

    PubMed

    Xu, Xiaoyin; Miller, Eric L; Chen, Dongbin; Sarhadi, Mansoor

    2004-02-01

    In this paper, we present an adaptive two-pass rank order filter to remove impulse noise in highly corrupted images. When the noise ratio is high, rank order filters, such as the median filter for example, can produce unsatisfactory results. Better results can be obtained by applying the filter twice, which we call two-pass filtering. To further improve the performance, we develop an adaptive two-pass rank order filter. Between the passes of filtering, an adaptive process is used to detect irregularities in the spatial distribution of the estimated impulse noise. The adaptive process then selectively replaces some pixels changed by the first pass of filtering with their original observed pixel values. These pixels are then kept unchanged during the second filtering. In combination, the adaptive process and the second filter eliminate more impulse noise and restore some pixels that are mistakenly altered by the first filtering. As a final result, the reconstructed image maintains a higher degree of fidelity and has a smaller amount of noise. The idea of adaptive two-pass processing can be applied to many rank order filters, such as a center-weighted median filter (CWMF), adaptive CWMF, lower-upper-middle filter, and soft-decision rank-order-mean filter. Results from computer simulations are used to demonstrate the performance of this type of adaptation using a number of basic rank order filters.

  4. Impulse Response Estimation for Spatial Resolution Enhancement in Ultrasonic NDE Imaging

    SciTech Connect

    Clark, G A

    2004-06-25

    This report describes a signal processing algorithm and MATLAB software for improving spatial resolution in ultrasonic nondestructive evaluation (NDE) imaging of materials. Given a measured reflection signal and an associated reference signal, the algorithm produces an optimal least-squares estimate of the impulse response of the material under test. This estimated impulse response, when used in place of the raw reflection signal, enhances the spatial resolution of the ultrasonic measurements by removing distortion caused by the limited-bandwidth transducers and the materials under test. The theory behind the processing algorithms is briefly presented, while the reader is referred to the bibliography for details. The main focus of the report is to describe how to use the MATLAB software. Two processing examples using actual ultrasonic measurements are provided for tutorial purposes.

  5. Statement of capabilities: Micropower Impulse Radar (MIR) technology applied to mine detection and imaging

    SciTech Connect

    Azevedo, S.G.; Gavel, D.T.; Mast, J.E.; Warhus, J.P.

    1995-03-13

    The Lawrence Livermore National Laboratory (LLNL) has developed radar and imaging technologies with potential applications in mine detection by the armed forces and other agencies involved in demining efforts. These new technologies use a patented ultra-wideband (impulse) radar technology that is compact, low-cost, and low power. Designated as Micropower Impulse Radar, these compact, self-contained radars can easily be assembled into arrays to form complete ground penetrating radar imaging systems. LLNL has also developed tomographic reconstruction and signal processing software capable of producing high-resolution 2-D and 3-D images of objects buried in materials like soil or concrete from radar data. Preliminary test results have shown that a radar imaging system using these technologies has the ability to image both metallic and plastic land mine surrogate targets buried in 5 to 10 cm of moist soil. In dry soil, the system can detect buried objects to a depth of 30 cm and more. This report describes LLNL`s unique capabilities and technologies that can be applied to the demining problem.

  6. High repetition rate operation of a photoinitiated impulse-enhanced electrically excited CO2 laser discharge using a burst-mode technique

    NASA Astrophysics Data System (ADS)

    Nikumb, S. K.; Seguin, H. J. J.; Seguin, V. A.; Presakarchuk, D.

    1988-10-01

    The incorporation of a gating signal into the trigger circuit of a photoinitiated, impulse-enhanced, electrically excited (PIE) laser system has permitted high-power, pulsed operation of a normally cw CO2 discharge. The 40 liter gain medium has been run at repetition rates approaching 1 kHz utilizing this approach. Plasma uniformity and stability have been significantly enhanced, such that a factor of two increase in electrical power deposition into the excited volume has been achieved. Results suggest that pulsed performance considerably in excess of that achievable under cw operating conditions can be realized through the adoption of this simple modification to the PIE ionization process.

  7. Achieving the image interpolation algorithm on the FPGA platform based on ImpulseC

    NASA Astrophysics Data System (ADS)

    Jia, Ge; Peng, Xianrong

    2013-10-01

    ImpulseC is based on the C language which can describe highly parallel and multi-process applications. It also generates a underlying hardware description for the dedicated process. To improve the famous bi-cubic interpolation algorithm, we design the bi-cubic convolution template algorithms with better computing performance and higher efficiency. The results of simulation show that the interpolation method not only improves the interpolation accuracy and image quality, but also preferably retains the texture of the image. Based on ImpulseC hardware design tools, we can make use of the compiler features to further parallelize the algorithm so that it is more conducive to the hardware implementation. Based on the Xilinx Spartan3 of XC3S4000 chip, our method achieves the real-time interpolation at the rate of 50fps. The FPGA experimental results show that the stream of output images after interpolation is robust and real-time. The summary shows that the allocation of hardware resources is reasonable. Compared with the existing hand-written HDL code, it has the advantages of parallel speedup. Our method provides a novel idea from C to FPGA-based embedded hardware system for software engineers.

  8. Adaptive correction procedure for TVL1 image deblurring under impulse noise

    NASA Astrophysics Data System (ADS)

    Bai, Minru; Zhang, Xiongjun; Shao, Qianqian

    2016-08-01

    For the problem of image restoration of observed images corrupted by blur and impulse noise, the widely used TVL1 model may deviate from both the data-acquisition model and the prior model, especially for high noise levels. In order to seek a solution of high recovery quality beyond the reach of the TVL1 model, we propose an adaptive correction procedure for TVL1 image deblurring under impulse noise. Then, a proximal alternating direction method of multipliers (ADMM) is presented to solve the corrected TVL1 model and its convergence is also established under very mild conditions. It is verified by numerical experiments that our proposed approach outperforms the TVL1 model in terms of signal-to-noise ratio (SNR) values and visual quality, especially for high noise levels: it can handle salt-and-pepper noise as high as 90% and random-valued noise as high as 70%. In addition, a comparison with a state-of-the-art method, the two-phase method, demonstrates the superiority of the proposed approach.

  9. Evolution of THz impulse imaging radar to 1550nm photoconductive switches

    NASA Astrophysics Data System (ADS)

    Brown, E. R.; Zhang, W.-D.; Feldman, A.; Harvey, T.; Mirin, R. P.; Sung, S.; Grundfest, W. S.; Taylor, Z. D.

    2016-05-01

    We present measurements of sub-bandgap photoconductivity and photoconductive switches using GaAs doped heavily with Er such that nanoparticles of ErAs are formed. In addition to strong resonant absorption centered around 1550 nm, the material provides strong sub-bandgap photoconductivity and >> μW average power levels when fabricated into an efficient (square spiral) THz antenna and driven by a 1550- nm ultrafast fiber laser. Photo-Hall measurements prove that the predominant photocarrier is the electron and the linearity of the 1550-nm photocurrent (with laser power) suggests that the photoconductivity is "extrinsic", not other possible mechanisms, such as two-photon absorption. These results have immediate relevance to the use of GaAs:Er switches as the transmitter in 1550-nm-driven THz imaging systems such as the "impulse imager" that we have successfully used for biomedical imaging applications.

  10. Acoustic radiation force impulse (ARFI) imaging of zebrafish embryo by high-frequency coded excitation sequence.

    PubMed

    Park, Jinhyoung; Lee, Jungwoo; Lau, Sien Ting; Lee, Changyang; Huang, Ying; Lien, Ching-Ling; Kirk Shung, K

    2012-04-01

    Acoustic radiation force impulse (ARFI) imaging has been developed as a non-invasive method for quantitative illustration of tissue stiffness or displacement. Conventional ARFI imaging (2-10 MHz) has been implemented in commercial scanners for illustrating elastic properties of several organs. The image resolution, however, is too coarse to study mechanical properties of micro-sized objects such as cells. This article thus presents a high-frequency coded excitation ARFI technique, with the ultimate goal of displaying elastic characteristics of cellular structures. Tissue mimicking phantoms and zebrafish embryos are imaged with a 100-MHz lithium niobate (LiNbO₃) transducer, by cross-correlating tracked RF echoes with the reference. The phantom results show that the contrast of ARFI image (14 dB) with coded excitation is better than that of the conventional ARFI image (9 dB). The depths of penetration are 2.6 and 2.2 mm, respectively. The stiffness data of the zebrafish demonstrate that the envelope is harder than the embryo region. The temporal displacement change at the embryo and the chorion is as large as 36 and 3.6 μm. Consequently, this high-frequency ARFI approach may serve as a remote palpation imaging tool that reveals viscoelastic properties of small biological samples.

  11. Total Variation with Overlapping Group Sparsity for Image Deblurring under Impulse Noise

    PubMed Central

    Liu, Gang; Huang, Ting-Zhu; Liu, Jun; Lv, Xiao-Guang

    2015-01-01

    The total variation (TV) regularization method is an effective method for image deblurring in preserving edges. However, the TV based solutions usually have some staircase effects. In order to alleviate the staircase effects, we propose a new model for restoring blurred images under impulse noise. The model consists of an ℓ1-fidelity term and a TV with overlapping group sparsity (OGS) regularization term. Moreover, we impose a box constraint to the proposed model for getting more accurate solutions. The solving algorithm for our model is under the framework of the alternating direction method of multipliers (ADMM). We use an inner loop which is nested inside the majorization minimization (MM) iteration for the subproblem of the proposed method. Compared with other TV-based methods, numerical results illustrate that the proposed method can significantly improve the restoration quality, both in terms of peak signal-to-noise ratio (PSNR) and relative error (ReE). PMID:25874860

  12. Imaging the impulsive alignment of noble-gas dimers via Coulomb explosion

    NASA Astrophysics Data System (ADS)

    Veltheim, A. von; Borchers, B.; Steinmeyer, G.; Rottke, H.

    2014-02-01

    The impulsive alignment of the noble-gas dimers Ne2, Ar2, Kr2, and Xe2 is experimentally investigated by determining the alignment through Coulomb explosion imaging after their double ionization. This approach yields a favorably detailed insight into the temporal evolution of the alignment succeeding the aligning laser pulse. Particular emphasis is put on analyzing higher order coherences induced in the density matrix as these coherences determine the details of the temporal evolution of the aligned molecular ensemble. The recorded data enable an extraction of polarizability anisotropies for the dimers and of their rotational constants in the vibrational ground state. At the elevated level of rotational excitation obtained, centrifugal distortion starts influencing the temporal evolution of the alignment.

  13. Impulse radar imaging for dispersive concrete using inverse adaptive filtering techniques

    SciTech Connect

    Arellano, J.; Hernandez, J.M.; Brase, J.

    1993-05-01

    This publication addresses applications of a delayed inverse model adaptive filter for modeled data obtained from short-pulse radar reflectometry. To determine the integrity of concrete, a digital adaptive filter was used, which allows compensation of dispersion and clutter generated by the concrete. A standard set of weights produced by an adaptive filter are used on modeled data to obtain the inverse-impulse response of the concrete. The data for this report include: Multiple target, nondispersive data; single-target, variable-size dispersive data; single-target, variable-depth dispersive data; and single-target, variable transmitted-pulse-width dispersive data. Results of this simulation indicate that data generated by the weights of the adaptive filter, coupled with a two-dimensional, synthetic-aperture focusing technique, successfully generate two-dimensional images of targets within the concrete from modeled data.

  14. Single- and Multiple- Track Location Shear Wave and Acoustic Radiation Force Impulse Imaging: Matched Comparison of Contrast, CNR, and Resolution

    PubMed Central

    Hollender, Peter J.; Rosenzweig, Stephen J.; Nightingale, Kathryn R.; Trahey, Gregg E.

    2014-01-01

    Acoustic radiation force impulse (ARFI) imaging and shear wave elasticity imaging (SWEI) use the dynamic response of tissue to impulsive mechanical stimulus to characterize local elasticity. A variant of conventional, multiple track location SWEI (MTL-SWEI), denoted single track location SWEI (STL-SWEI) offers the promise of creating speckle-free shear wave images. This work compares the three imaging modalities using a high push and track beam density combined acquisition sequence to image inclusions of different sizes and contrasts. STL-SWEI is shown to have significantly higher CNR than MTL-SWEI, allowing for operation at higher resolution. ARFI and STL-SWEI perform similarly in the larger inclusions, with STL-SWEI providing better visualization of small targets ≤2.5 mm in diameter. The processing of each modality introduces different trade-offs between smoothness and resolution of edges and structures; these are discussed in detail. PMID:25701531

  15. The electric organ discharge of pulse gymnotiforms: the transformation of a simple impulse into a complex spatio-temporal electromotor pattern

    PubMed

    Caputi

    1999-05-01

    An understanding of how the nervous system processes an impulse-like input to yield a stereotyped, species-specific electromotor output is relevant for electric fish physiology, but also for understanding the general mechanisms of coordination of effector patterns. In pulse gymnotids, the electromotor system is repetitively activated by impulse-like signals generated by a pacemaker nucleus in the medulla. This nucleus activates a set of relay cells whose axons descend along the spinal cord and project to electromotor neurones which, in turn, project to electrocytes. Relay neurones, electromotor neurones and electrocytes may be considered as layers of a network arranged with a lattice hierarchy. This network is able to coordinate a spatio-temporal pattern of postsynaptic and action currents generated by the electrocyte membranes. Electrocytes may be innervated at their rostral face, at their caudal face or at both faces, depending on the site of the organ and the species. Thus, the species-specific electric organ discharge patterns depend on the electric organ innervation pattern and on the coordinated activation of the electrocyte faces. The activity of equally oriented faces is synchronised by a synergistic combination of delay lines. The activation of oppositely oriented faces is coordinated in a precise sequence resulting from the orderly recruitment of subsets of electromotor neurones according to the 'size principle' and to their position along the spinal cord. The body of the animal filters the electric organ output electrically, and the whole fish is transformed into a distributed electric source.

  16. Electric organ discharges and electric images during electrolocation

    NASA Technical Reports Server (NTRS)

    Assad, C.; Rasnow, B.; Stoddard, P. K.

    1999-01-01

    Weakly electric fish use active electrolocation - the generation and detection of electric currents - to explore their surroundings. Although electrosensory systems include some of the most extensively understood circuits in the vertebrate central nervous system, relatively little is known quantitatively about how fish electrolocate objects. We believe a prerequisite to understanding electrolocation and its underlying neural substrates is to quantify and visualize the peripheral electrosensory information measured by the electroreceptors. We have therefore focused on reconstructing both the electric organ discharges (EODs) and the electric images resulting from nearby objects and the fish's exploratory behaviors. Here, we review results from a combination of techniques, including field measurements, numerical and semi-analytical simulations, and video imaging of behaviors. EOD maps are presented and interpreted for six gymnotiform species. They reveal diverse electric field patterns that have significant implications for both the electrosensory and electromotor systems. Our simulations generated predictions of the electric images from nearby objects as well as sequences of electric images during exploratory behaviors. These methods are leading to the identification of image features and computational algorithms that could reliably encode electrosensory information and may help guide electrophysiological experiments exploring the neural basis of electrolocation.

  17. High power impulse magnetron sputtering and related discharges: scalable plasma sources for plasma-based ion implantation and deposition

    SciTech Connect

    Anders, Andre

    2009-09-01

    High power impulse magnetron sputtering (HIPIMS) and related self-sputtering techniques are reviewed from a viewpoint of plasma-based ion implantation and deposition (PBII&D). HIPIMS combines the classical, scalable sputtering technology with pulsed power, which is an elegant way of ionizing the sputtered atoms. Related approaches, such as sustained self-sputtering, are also considered. The resulting intense flux of ions to the substrate consists of a mixture of metal and gas ions when using a process gas, or of metal ions only when using `gasless? or pure self-sputtering. In many respects, processing with HIPIMS plasmas is similar to processing with filtered cathodic arc plasmas, though the former is easier to scale to large areas. Both ion implantation and etching (high bias voltage, without deposition) and thin film deposition (low bias, or bias of low duty cycle) have been demonstrated.

  18. Intracardiac Acoustic Radiation Force Impulse (ARFI) and Shear Wave Imaging in Pigs with Focal Infarctions

    PubMed Central

    Hollender, Peter; Bradway, David; Wolf, Patrick; Goswami, Robi; Trahey, Gregg

    2013-01-01

    Four pigs, three with focal infarctions in the apical intraventricular septum (IVS) and/or left ventricular free wall (LVFW), were imaged with an intracardiac echocardiography (ICE) transducer. Custom beam sequences were used to excite the myocardium with focused acoustic radiation force (ARF) impulses and image the subsequent tissue response. Tissue displacement in response to the ARF excitation was calculated with a phase-based estimator, and transverse wave magnitude and velocity were each estimated at every depth. The excitation sequence was repeated rapidly, either in the same location to generate 40 Hz M-Modes at a single steering angle, or with a modulated steering angle to synthesize 2-D displacement magnitude and shear wave velocity images at 17 points in the cardiac cycle. Both types of images were acquired from various views in the right and left ventricles, in and out of infarcted regions. In all animals, ARFI and SWEI estimates indicated diastolic relaxation and systolic contraction in non-infarcted tissues. The M-Mode sequences showed high beat-to-beat spatio-temporal repeatability of the measurements for each imaging plane. In views of noninfarcted tissue in the diseased animals, no significant elastic remodeling was indicated when compared to the control. Where available, views of infarcted tissue were compared to similar views from the control animal. In views of the LVFW, the infarcted tissue presented as stiff and non-contractile compared to the control. In a view of the IVS, no significant difference was seen between infarcted and healthy tissue, while in another view, a heterogeneous infarction was seen presenting itself as non-contractile in systole. PMID:25004538

  19. New Developments in Human Neurocognition: Clinical, Genetic and Brain Imaging Correlates of Impulsivity and Compulsivity

    PubMed Central

    Fineberg, Naomi A.; Chamberlain, Samuel R.; Goudriaan, Anna E.; Stein, Dan J.; Vanderschuren, Louk J.M.J.; Gillan, Claire M.; Shekar, Sameer; Gorwood, Philip A.P.M.; Voon, Valerie; Morein-Zamir, Sharon; Denys, Damiaan; Sahakian, Barbara J.; Moeller, F. Gerard; Robbins, Trevor W.; Potenza, Marc N.

    2014-01-01

    Impulsivity and compulsivity represent useful conceptualizations that involve dissociable cognitive functions, mediated by neuroanatomically and neurochemically distinct components of cortico-subcortical circuitry. The constructs were historically viewed as diametrically opposed, with impulsivity being associated with risk-seeking and compulsivity with harm-avoidance. However, they are increasingly recognized to be linked by shared neuropsychological mechanisms involving dysfunctional inhibition of thoughts and behaviors. In this paper, we selectively review new developments in the investigation of the neurocognition of impulsivity and compulsivity in humans, in order to advance our understanding of the pathophysiology of impulsive, compulsive and addictive disorders and indicate new directions for research. PMID:24512640

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

    SciTech Connect

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

    2015-11-15

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

  1. Imaging impulse control disorders in Parkinson's disease and their relationship to addiction.

    PubMed

    Ray, Nicola J; Strafella, Antonio P

    2013-04-01

    Established substance addictions and impulse control disorders (ICDs) such as pathological gambling share similar underlying neurobiology, and recent data extends these commonalities to the risk factors that increase an individuals' susceptibility to develop such behaviours. In Parkinson's disease (PD), impulse control disorders (ICDs) are increasingly recognised to develop after patients begin dopamine (DA) restoration therapy, in particular DA agonists. In both the PD and non-PD population, more impulsive individuals are at increased risk for impulse control disorders. Here, we review the neuroimaging data confirming the connection between addiction and ICDs, and revealing how DA agonists might cause specific alterations of basal ganglia and cortical function that vary as a function of an individuals' propensity for impulsivity.

  2. Management of nipple discharge and the associated imaging findings.

    PubMed

    Patel, Bhavika K; Falcon, Shannon; Drukteinis, Jennifer

    2015-04-01

    Nipple discharge is commonly encountered by health care providers, accounting for 2%-5% of medical visits by women. Because nipple discharge is the presenting symptom in 5% to 12% of breast cancers, it causes considerable anxiety for both patient and providers. Furthermore, the work-up and management of nipple discharge can be confusing. Fortunately, the cause of nipple discharge is usually benign, so the primary goal of evaluation and management is separation of patients with pathologic causes of discharge from those with benign or physiologic causes. The evaluation of nipple discharge requires a thorough history, careful physical examination, and an informed approach that selects the most suitable diagnostic modality. Primary care providers, working with their radiologists and surgeons, are well positioned to design appropriate diagnostic and management protocols to assess and treat nipple discharge. A thoughtful and prudent approach to nipple discharge should alleviate patient anxiety by efficiently and effectively defining the underlying etiology.

  3. Evaluation of graft stiffness using acoustic radiation force impulse imaging after living donor liver transplantation.

    PubMed

    Ijichi, Hideki; Shirabe, Ken; Matsumoto, Yoshihiro; Yoshizumi, Tomoharu; Ikegami, Toru; Kayashima, Hiroto; Morita, Kazutoyo; Toshima, Takeo; Mano, Yohei; Maehara, Yoshihiko

    2014-11-01

    Acoustic radiation force impulse (ARFI) imaging is an ultrasound-based modality to evaluate tissue stiffness using short-duration acoustic pulses in the region of interest. Virtual touch tissue quantification (VTTQ), which is an implementation of ARFI, allows quantitative assessment of tissue stiffness. Twenty recipients who underwent living donor liver transplantation (LDLT) for chronic liver diseases were enrolled. Graft types included left lobes with the middle hepatic vein and caudate lobes (n = 11), right lobes (n = 7), and right posterior segments (n = 2). They underwent measurement of graft VTTQ during the early post-LDLT period. The VTTQ value level rose after LDLT, reaching a maximum level on postoperative day 4. There were no significant differences in the VTTQ values between the left and right lobe graft types. Significant correlations were observed between the postoperative maximum value of VTTQ and graft volume-to-recipient standard liver volume ratio, portal venous flow to graft volume ratio, and post-LDLT portal venous pressure. The postoperative maximum serum alanine aminotransferase level and ascites fluid production were also significantly correlated with VTTQ. ARFI may be a useful diagnostic tool for the noninvasive and quantitative evaluation of the severity of graft dysfunction after LDLT.

  4. Testicular microlithiasis and preliminary experience of acoustic radiation force impulse imaging

    PubMed Central

    Osther, Palle Jørn Sloth; Rafaelsen, Søren Rafael

    2016-01-01

    Background Elastography of the testis can be used as a part of multiparametric examination of the scrotum. Purpose To determine the testicular stiffness using acoustic radiation force impulse imaging (ARFI) technique in men with testicular microlithiasis (TML). Material and Methods In 2013, 12 patients with diagnosed testicular microlithiasis in 2008 (mean age, 51 years; age range, 25–76 years) underwent a 5-year follow-up B-mode ultrasonography with three ARFI elastography measurements of each testis. We used a Siemens Acuson S3000 machine. Results No malignancy was found at the 5-year follow-up B-mode and elastography in 2013. However, we found an increase in TML; in the previous ultrasonography in 2008, eight men had bilateral TML, whereas in 2013, 10 men were diagnosed with bilateral TML. The mean elasticity of testicles with TML was 0.82 m/s (interquartile range [IQR], 0.72–0.88 m/s; range, 65–1.08 m/s). Conclusion Elastography velocity of testis with TML seems to be in the same velocity range as in men with normal testis tissue. PMID:27504193

  5. X-ray Diffraction and Multi-Frame Phase Contrast Imaging Diagnostics for IMPULSE at the Advanced Photon Source

    SciTech Connect

    Iverson, Adam; Carlson, Carl; Young, Jason; Curtis, Alden; Jensen, Brian; Ramos, Kyle; Yeager, John; Montgomery, David; Fezza, Kamel

    2013-07-08

    The diagnostic needs of any dynamic loading platform present unique technical challenges that must be addressed in order to accurately measure in situ material properties in an extreme environment. The IMPULSE platform (IMPact system for Ultrafast Synchrotron Experiments) at the Advanced Photon Source (APS) is no exception and, in fact, may be more challenging, as the imaging diagnostics must be synchronized to both the experiment and the 60 ps wide x-ray bunches produced at APS. The technical challenges of time-resolved x-ray diffraction imaging and high-resolution multi-frame phase contrast imaging (PCI) are described in this paper. Example data from recent IMPULSE experiments are shown to illustrate the advances and evolution of these diagnostics with a focus on comparing the performance of two intensified CCD cameras and their suitability for multi-frame PCI. The continued development of these diagnostics is fundamentally important to IMPULSE and many other loading platforms and will benefit future facilities such as the Dynamic Compression Sector at APS and MaRIE at Los Alamos National Laboratory.

  6. Comparison of ultrasound B-mode, strain imaging, acoustic radiation force impulse displacement and shear wave velocity imaging using real time clinical breast images

    NASA Astrophysics Data System (ADS)

    Manickam, Kavitha; Machireddy, Ramasubba Reddy; Raghavan, Bagyam

    2016-04-01

    It has been observed that many pathological process increase the elastic modulus of soft tissue compared to normal. In order to image tissue stiffness using ultrasound, a mechanical compression is applied to tissues of interest and local tissue deformation is measured. Based on the mechanical excitation, ultrasound stiffness imaging methods are classified as compression or strain imaging which is based on external compression and Acoustic Radiation Force Impulse (ARFI) imaging which is based on force generated by focused ultrasound. When ultrasound is focused on tissue, shear wave is generated in lateral direction and shear wave velocity is proportional to stiffness of tissues. The work presented in this paper investigates strain elastography and ARFI imaging in clinical cancer diagnostics using real time patient data. Ultrasound B-mode imaging, strain imaging, ARFI displacement and ARFI shear wave velocity imaging were conducted on 50 patients (31 Benign and 23 malignant categories) using Siemens S2000 machine. True modulus contrast values were calculated from the measured shear wave velocities. For ultrasound B-mode, ARFI displacement imaging and strain imaging, observed image contrast and Contrast to Noise Ratio were calculated for benign and malignant cancers. Observed contrast values were compared based on the true modulus contrast values calculated from shear wave velocity imaging. In addition to that, student unpaired t-test was conducted for all the four techniques and box plots are presented. Results show that, strain imaging is better for malignant cancers whereas ARFI imaging is superior than strain imaging and B-mode for benign lesions representations.

  7. Dealing with Impulsivity.

    ERIC Educational Resources Information Center

    Neidhardt, Janet

    1987-01-01

    A mother recounts her neurologically impaired son's struggles and progress in combating impulsivity in his work and social habits. Now 23 years old, employed full-time, and off medication, the son is still impulsive, has problems with social skills, but has improved his self-image through a photography hobby. (CB)

  8. Acoustic radiation force impulse imaging for assessing liver fibrosis in alcoholic liver disease

    PubMed Central

    Kiani, Anita; Brun, Vanessa; Lainé, Fabrice; Turlin, Bruno; Morcet, Jeff; Michalak, Sophie; Le Gruyer, Antonia; Legros, Ludivine; Bardou-Jacquet, Edouard; Gandon, Yves; Moirand, Romain

    2016-01-01

    AIM: To evaluate the performance of elastography by ultrasound with acoustic radiation force impulse (ARFI) in determining fibrosis stage in patients with alcoholic liver disease (ALD) undergoing alcoholic detoxification in relation to biopsy. METHODS: Eighty-three patients with ALD undergoing detoxification were prospectively enrolled. Each patient underwent ARFI imaging and a liver biopsy on the same day. Fibrosis was staged according to the METAVIR scoring system. The median of 10 valid ARFI measurements was calculated for each patient. RESULTS: Sixty-nine males and thirteen females (one patient excluded due to insufficient biopsy size) were assessed with a mean alcohol consumption of 132.4 ± 128.8 standard drinks per week and mean cumulative year duration of 17.6 ± 9.5 years. Sensitivity and specificity were respectively 82.4% (0.70-0.95) and 83.3% (0.73-0.94) (AUROC = 0.87) for F ≥ 2 with a cut-off value of 1.63m/s; 82.4% (0.64-1.00) and 78.5% (0.69-0.89) (AUROC = 0.86) for F ≥ 3 with a cut-off value of 1.84m/s; and 92.3% (0.78-1.00] and 81.6% (0.72-0.90) (AUROC = 0.89) for F = 4 with a cut-off value of 1.94 m/s. CONCLUSION: ARFI is an accurate, non-invasive and easy method for assessing liver fibrosis in patients with ALD undergoing alcoholic detoxification. PMID:27239119

  9. Objects, decision considerations and self-image in men's and women's impulse purchases.

    PubMed

    Dittmar, H; Beattie, J; Friese, S

    1996-09-01

    Current theories in economics, marketing, and psychology fail to explain underlying reasons for impulse buying and, crucially, why certain goods (e.g., clothes) are bought impulsively more than others (e.g., basic kitchen equipment). We propose and examine a social psychological model, which predicts that people impulse buy to acquire material symbols of personal and social identity. We predict that consumers will differ systematically in the goods they buy on impulse, and in their reasons for doing so, depending on their attitudes towards shopping, and also along important social categories, such as gender. Specifically, our theoretical model-drawing on a social constructionist model of material possessions (e.g., Dittmar, 1992) and symbolic self-completion theory (e.g. Wicklund and Gollwitzer, 1982)-leads to three sets of hypotheses: (i) some consumer durables are more likely to be bought on impulse than others, and there may be gender differences in object choices, (ii) differences will emerge in the buying considerations (e.g., functional, emotional, symbolic) that are used for impulse and planned buying, and (iii) magnitude of self-discrepancies will predict relative impulse buying frequency and the buying considerations used, if the individual uses consumption as a self-completion strategy. These predictions were expected to hold particularly strongly for individuals high in compulsive shopping tendencies. We test our model in a questionnaire study with a sample of British consumers (n = 61). The results lend support to all three sets of hypotheses. The implications of these findings are discussed with respect to economic and consumer theory, and the treatment offered to the increasing number of 'addicted' shoppers.

  10. Turbulent-PSO-Based Fuzzy Image Filter With No-Reference Measures for High-Density Impulse Noise.

    PubMed

    Chou, Hsien-Hsin; Hsu, Ling-Yuan; Hu, Hwai-Tsu

    2013-02-01

    Digital images are often corrupted by impulsive noise during data acquisition, transmission, and processing. This paper presents a turbulent particle swarm optimization (PSO) (TPSO)-based fuzzy filtering (or TPFF for short) approach to remove impulse noise from highly corrupted images. The proposed fuzzy filter contains a parallel fuzzy inference mechanism, a fuzzy mean process, and a fuzzy composition process. To a certain extent, the TPFF is an improved and online version of those genetic-based algorithms which had attracted a number of works during the past years. As the PSO is renowned for its ability of achieving success rate and solution quality, the superiority of the TPFF is almost for sure. In particular, by using a no-reference Q metric, the TPSO learning is sufficient to optimize the parameters necessitated by the TPFF. Therefore, the proposed fuzzy filter can cope with practical situations where the assumption of the existence of the "ground-truth" reference does not hold. The experimental results confirm that the TPFF attains an excellent quality of restored images in terms of peak signal-to-noise ratio, mean square error, and mean absolute error even when the noise rate is above 0.5 and without the aid of noise-free images.

  11. Newborn jaundice - discharge

    MedlinePlus

    ... Jaundice of the newborn - discharge; Neonatal hyperbilirubinemia - discharge; Breastfeeding jaundice - discharge; Physiologic jaundice - discharge Images Exchange transfusion - series Infant jaundice References Kaplan M, ...

  12. Instantaneous Impulses.

    ERIC Educational Resources Information Center

    Erlichson, Herman

    2000-01-01

    Describes an experiment that extends Newton's instantaneous-impulse method of orbital analysis to a graphical method of orbit determination. Discusses the experiment's usefulness for teaching both horizontal projectile motion and instantaneous impulse. (WRM)

  13. Television image of a large upward electrical discharge above a thunderstorm system

    NASA Technical Reports Server (NTRS)

    Franz, R. C.; Nemzek, R. J.; Winckler, J. R.

    1990-01-01

    A low light-level TV camera is used to obtain an unusual image of luminous electrical discharge over a thunderstorm 250 km from the observation site. The image is presented and the discharge in the image is described. It is suggested that the image is probably due to two localized electric charge concentrations at the cloud tops. The hazard of these discharges for aircraft and rocket launches is examined. Consideration is given to the possibility that these discharges may account for unexplained photometric observations of distant lightning events that show a low rise rate of the luminous pulse and no electromagnetic sferic pulse like that in cloud-to-earth lightning strokes. The photometric events of this type that occurred on September 22-23, 1989 during hurricane Hugo are noted.

  14. Impulsive radio discharges near Saturn

    NASA Technical Reports Server (NTRS)

    Evans, D. R.; Warwick, J. W.; Pearce, J. B.; Carr, T. D.; Schauble, J. J.

    1981-01-01

    Nonthermal radio emissions from the Saturn system were first detected by the Voyager planetary radio astronomy (PRA) experiment on board Voyager 1 in January 1980. Since then emission between 100 kHz and 1 MHz from the planet, termed Saturn kilometric radiation (SKR), has been received almost continuously. A description is presented of eight characteristics which have been fairly well defined by the Voyager 1 encounter. These include a very flat broadband frequency spectrum, a period of approximately 10 h 10 min, a change in the envelope shape of episodes between pre and postencounter, an intensity population structure typical of plural populations, and an episodic structure of a width of approximately 180 deg. It was found that postencounter episodes continue for about three times as long as preencounter ones, and that postencounter bursts are left-circularly polarized at high frequencies. At least one episode shows the onset of high frequency events some time before that of lower frequency ones.

  15. An efficient way to evidence and to measure the metal ion fraction in high power impulse magnetron sputtering (HiPIMS) post-discharge with Pt, Au, Pd and mixed targets

    NASA Astrophysics Data System (ADS)

    Cuynet, S.; Lecas, T.; Caillard, A.; Brault, P.

    2016-12-01

    The proportion of metal ions in a high power impulse magnetron sputtering discharge is key information for the potential development of new materials and new layer architectures deposited by this technique. This paper aims to measure this proportion by using a homemade system consisting of a quartz crystal microbalance and a grid energy analyser assembly. Such a system yields relevant results on the composition of the post-discharge depending on the nature of the gas (Ar, Kr, Xe) and the target materials (Pt, Pd, Au, 50\\text{Au}50$ and 5\\text{Pd}95$ ). In our conditions, the highest proportion of metal ions in the post-discharge are obtained by using Ar gas and reaches 10 %, 12 %, 50 %, 19 % and 88 % for Pt, Au, Pd, 50\\text{Au}50$ and 5\\text{Pd}95$ targets, respectively.

  16. Acoustic radiation force impulse (ARFI) imaging: Characterizing the mechanical properties of tissues using their transient response to localized force

    NASA Astrophysics Data System (ADS)

    Nightingale, Kathryn R.; Palmeri, Mark L.; Congdon, Amy N.; Frinkely, Kristin D.; Trahey, Gregg E.

    2004-05-01

    Acoustic radiation force impulse (ARFI) imaging utilizes brief, high energy, focused acoustic pulses to generate radiation force in tissue, and conventional diagnostic ultrasound methods to detect the resulting tissue displacements in order to image the relative mechanical properties of tissue. The magnitude and spatial extent of the applied force is dependent upon the transmit beam parameters and the tissue attenuation. Forcing volumes are on the order of 5 mm3, pulse durations are less than 1 ms, and tissue displacements are typically several microns. Images of tissue displacement reflect local tissue stiffness, with softer tissues (e.g., fat) displacing farther than stiffer tissues (e.g., muscle). Parametric images of maximum displacement, time to peak displacement, and recovery time provide information about tissue material properties and structure. In both in vivo and ex vivo data, structures shown in matched B-mode images are in good agreement with those shown in ARFI images, with comparable resolution. Potential clinical applications under investigation include soft tissue lesion characterization, assessment of focal atherosclerosis, and imaging of thermal lesion formation during tissue ablation procedures. Results from ongoing studies will be presented. [Work supported by NIH Grant R01 EB002132-03, and the Whitaker Foundation. System support from Siemens Medical Solutions USA, Inc.

  17. Time-resolved imaging of nanosecond-pulsed micro-discharges in heptane

    NASA Astrophysics Data System (ADS)

    Hamdan, A.; Marinov, I.; Rousseau, A.; Belmonte, T.

    2014-02-01

    Nanosecond-pulsed micro-discharges in heptane are studied by time-resolved imaging in pin-to-plate configuration. When a voltage of +5 kV is applied to the pin electrode, the discharge exhibits one maximum in light intensity. At +15 kV, filtered images show that up to three maxima can be identified. These maxima are associated with local electron-ion recombination and bremsstrahlung emission and attributed to the development of a complex space-charge field. In the post-discharge, the dynamics of the gas bubble can be simulated by the Gilmore model, and the pressure evolution in this bubble is predicted. From our results, it seems reasonable to think that the gas bubble develops from the post-discharge of the spark. Results obtained by using the double-pulse technique show that light emission during the post-discharge of the second discharge lasts 10 times longer than the post-discharge of the first spark. The pressure drop in the gas bubble, predicted by the Gilmore model, is used to explain this result and it provides a control method by optical diagnostics in liquids.

  18. Two-frequency imaging of microwave impulsive flares near the solar limb

    NASA Technical Reports Server (NTRS)

    Dulk, G. A.; Bastian, T. S.; Kane, S. R.

    1986-01-01

    VLA observations of two impulsive microwave and hard X-ray flares close to the solar limb on November 21 and 22, 1981 are presently interpreted in terms of an inhomogeneous flare volume, with the magnetic field strength and orientation varying with position both transverse to, and along, the line-of-sight. The 15 GHz radiation of the flares on both days may be due to electrons of E = 300 keV in weak nonthermal tail; the absence of 4.9 GHz radiation from these sources is attributed to absorption along the ray path from the flare to the earth, on the basis of the fact that thermal bremsstrahlung and gyrosynchrotron radiation mechanisms generate more low than high frequency radiation.

  19. Serial changes of liver stiffness measured by acoustic radiation force impulse imaging in acute liver failure: a case report.

    PubMed

    Kuroda, Hidekatsu; Takikawa, Yasuhiro; Onodera, Mio; Kakisaka, Keisuke; Yoshida, Yuichi; Kataoka, Koujiro; Sawara, Kei; Miyamoto, Yasuhiro; Oikawa, Kanta; Endo, Ryujin; Suzuki, Kazuyuki

    2012-02-01

    Acoustic radiation force impulse (ARFI) imaging is a new technology used to determine liver elasticity. We report the case of a patient that survived hyperacute-type acute liver failure (ALF) and who showed a dramatic change in the value of shear wave velocity (SWV) measured by ARFI, which corresponded with the severity of her liver damage. The value of SWV increased significantly up to 3.6 ± 0.3 m/s during the encephalopathy phase and then decreased along with the recovery of liver function, the blood flow of the right portal vein, and the liver volume. These findings suggest the value of SWV in ALF as a reliable marker of liver tissue damage. Further investigations of the pathophysiological significance of SWV in ALF are warranted.

  20. Reduced anterior corpus callosum white matter integrity is related to increased impulsivity and reduced discriminability in cocaine-dependent subjects: diffusion tensor imaging.

    PubMed

    Moeller, Frederick Gerard; Hasan, Khader M; Steinberg, Joel L; Kramer, Larry A; Dougherty, Donald M; Santos, Rafael M; Valdes, Ignacio; Swann, Alan C; Barratt, Ernest S; Narayana, Ponnada A

    2005-03-01

    Brain imaging studies find evidence of prefrontal cortical dysfunction in cocaine-dependent subjects. Similarly, cocaine-dependent subjects have problems with behaviors related to executive function and impulsivity. Since prefrontal cortical axonal tracts cross between hemispheres in the corpus callosum, it is possible that white matter integrity in the corpus callosum could also be diminished in cocaine-dependent subjects. The purpose of this study was to compare corpus callosum white matter integrity as measured by the fractional anisotropy (FA) on diffusion tensor imaging (DTI) between 18 cocaine-dependent subjects and 18 healthy controls. The Barratt Impulsiveness Scale (BIS-11) and a continuous performance test: the Immediate and Delayed Memory Task (IMT/DMT) were also collected. Results of the DTI showed significantly reduced FA in the genu and rostral body of the anterior corpus callosum in cocaine-dependent subjects compared to controls. Cocaine-dependent subjects also had significantly higher BIS-11 scores, greater impulsive (commission) errors, and reduced ability to discriminate target from catch stimuli (discriminability) on the IMT/DMT. Within cocaine dependent subjects there was a significant negative correlation between FA in the anterior corpus callosum and behavioral laboratory measured impulsivity, and there was a positive correlation between FA and discriminability. The finding that reduced integrity of anterior corpus callosum white matter in cocaine users is related to impaired impulse control and reduced ability to discriminate between target and catch stimuli is consistent with prior theories regarding frontal cortical involvement in impaired inhibitory control in cocaine-dependent subjects.

  1. Localization of focal epileptic discharges using functional connectivity magnetic resonance imaging

    PubMed Central

    Stufflebeam, Steven M.; Liu, Hesheng; Sepulcre, Jorge; Tanaka, Naoaki; Buckner, Randy L.; Madsen, Joseph R.

    2011-01-01

    Object In patients with medically refractory epilepsy the accurate localization of the seizure onset zone is critical for successful surgical treatment. The object of this study was to investigate whether the degree of coupling of spontaneous brain activity as measured with functional connectivity MR imaging (fcMR imaging) can accurately identify and localize epileptic discharges. Methods The authors studied 6 patients who underwent fcMR imaging presurgical mapping and subsequently underwent invasive electroencephalography. Results Focal regions of statistically significant increases in connectivity were identified in 5 patients when compared with an ad hoc normative sample of 300 controls. The foci identified by fcMR imaging overlapped the epileptogenic areas identified by invasive encephalography in all 5 patients. Conclusions These results suggest that fcMR imaging may provide an effective high–spatial resolution and noninvasive method of localizing epileptic discharges in patients with refractory epilepsy. PMID:21351832

  2. Spectroscopic imaging of metal halide high-intensity discharge lamps

    NASA Astrophysics Data System (ADS)

    Bonvallet, Geoffrey A.

    The body of this work consists of three main research projects. An optical- and near-ultraviolet-wavelength absorption study sought to determine absolute densities of ground and excited level Sc atoms, ground level Sc + ions, and ground level Na atoms in a commercial 250 W metal halide high intensity discharge lamp during operation. These measurements also allowed the determination of the arc temperature and absolute electron density as functions of radius. Through infrared emission spectroscopy, relative densities of sodium and scandium were determined as functions of radius. Using the absolute densities gained from the optical experiment, these relative densities were calibrated. In addition, direct observation of the infrared emission allowed us to characterize the infrared power losses of the lamp. When considered as a fraction of the overall power consumption, the near-infrared spectral power losses were not substantial enough to warrant thorough investigation of their reduction in these lamps. The third project was an attempt to develop a portable x-ray diagnostic experiment. Two-dimensional spatial maps of the lamps were analyzed to determine absolute elemental mercury densities and the arc temperature as a function of radius. Two methods were used to improve the calibration of the density measurements and to correct for the spread in x-ray energy: known solutions of mercury in nitric acid, and an arc lamp which was uniformly heated to evaporate the mercury content. Although many complexities arose in this experiment, its goal was successfully completed.

  3. Fast imaging of intermittent electrospraying of water with positive corona discharge

    NASA Astrophysics Data System (ADS)

    Pongrác, B.; Kim, H. H.; Janda, M.; Martišovitš, V.; Machala, Z.

    2014-08-01

    The effect of the electrospraying of water in combination with a positive direct current (dc) streamer corona discharge generated in air was investigated in this paper. We employed high-speed camera visualizations and oscilloscopic discharge current measurements in combination with an intensified charge-coupled device camera for fast time-resolved imaging. The repetitive process of Taylor cone formation and droplet formation from the mass fragments of water during the electrospray was visualized. Depending on the applied voltage, the following intermittent modes of electrospraying typical for water were observed: dripping mode, spindle mode, and oscillating-spindle mode. The observed electrospraying modes were repetitive with a frequency of a few hundreds of Hz, as measured from the fast image sequences. This frequency agreed well with the frequency of the measured streamer current pulses. The presence of filamentary streamer discharges at relatively low voltages probably prevented the establishment of a continuous electrospray in the cone-jet mode. After each streamer, a positive glow corona discharge was established on the water filament tip, and it propagated from the stressed electrode along with the water filament elongation. The results show a reciprocal character of intermittent electrospraying of water, and the presence of corona discharge, where both the electrospray and the discharge affect each other. The generation of a corona discharge from the water cone depended on the repetitive process of the cone formation. Also, the propagation and curvature of the water filament were influenced by the discharge and its resultant space charge. Furthermore, these phenomena were partially influenced by the water conductivity.

  4. Impact of Acoustic Radiation Force Impulse Imaging in Clinical Practice of Patients after Orthotopic Liver Transplantation

    PubMed Central

    Wildner, Dane; Strobel, Deike; Konturek, Peter C.; Görtz, Rüdiger S.; Croner, Roland S.; Neurath, Markus F.; Zopf, Steffen

    2014-01-01

    Background Acoustic radiation force impulse (ARFI) elastography is a reliable diagnostic device for quantitative non-invasive assessment of liver fibrosis in patients with chronic liver disease. The aim of our prospective study was to evaluate the impact of ARFI in patients after orthotopic liver transplantation (OLT). Therefore, we compared ARFI shear wave velocities with clinical features, non-invasive markers, and the histology of patients following OLT. Material/Methods Post-transplant patients underwent a clinical examination and blood samples were taken. B-mode and Doppler ultrasound (US) of the portal vein and the hepatic artery were performed. Subsequently, a minimum of 10 valid ARFI values were measured in the left and right liver lobe. Liver biopsy was performed if indicated. Results Between May 2012 and May 2014, 58 Patients after OLT were included in the prospective study. Laboratory markers and aspartate aminotransferase-to-platelet ratio index (APRI) correlated with ARFI values (r=0.44, p<0.001). The histological (n=22) fibrosis score (Ludwig) was significantly correlated with the ARFI of the biopsy site (r=0.55, p=0.008). The mean shear-wave velocities were significantly increased in advanced fibrosis (F≤2 1.57±0.57 m/s; F≥3 2.85±0.66 m/s; p<0.001), obstructive cholestasis and active viral hepatitis. The area under the receiver operating characteristic (AUROC) curves for the accuracy of ARFI were 74% (F≥1), 73% (F≥2), 93% (F≥3), and 80% (=F4). Conclusions ARFI elastography correlates well with laboratory values and with noninvasive and invasive markers of fibrosis in patients after OLT. In this regard, elevated ARFI-velocities should be interpreted with caution in the context of obstructive cholestasis and active viral disease. PMID:25342166

  5. Acoustic radiation force impulse imaging of kidneys – a phantom study

    PubMed Central

    Januszewicz, Magdalena

    2016-01-01

    Aim of the study Since there have been only few works reporting the diagnosis of kidneys using Acoustic Radiation Force Impulse technique and those works do not provide consistent results of shear wave velocity measurements in renal tissue, we have decided to use kidney phantoms with known properties to examine the reliability of the method itself in a controlled setup similar to kidneys examination. Materials and methods Four gelatin-based phantoms imitating different clinical situations were manufactured – two with thick and two with thin renal cortex, each type at a depth similar to a normal-weight or overweight patient. For each phantom, a series of interest points was chosen and for each point 20 Shear Wave Velocity measurements were taken using the build-in Virtual Touch Tissue Quantification™ tool in a Siemens Acuson S2000 ultrasound scanner equipped with a 6C1 HD Transducer (Siemens Mountainview, USA). Results Mean Shear Wave Velocity values obtained for all the examined points ranged from 2.445 to 3.941 m/s, with standard deviation exceeding 0.1 in only one case out of 29 points, but differing significantly between all points. Conclusions The obtained results indicate that the method is highly reliable as long as the measurement volume contains a uniform tissue region. If the measurement window covers a region with different properties even partially, the obtained results are affected. The variance of measured values on the other hand is not affected by the said non-uniformity of material under examination. Furthermore, the variance of measured values does not show a clear dependency on the depth at which the shear wave velocities are measured. PMID:28138404

  6. Evaluating the intensity of the acoustic radiation force impulse (ARFI) in intravascular ultrasound (IVUS) imaging: Preliminary in vitro results.

    PubMed

    Shih, Cho-Chiang; Lai, Ting-Yu; Huang, Chih-Chung

    2016-08-01

    The ability to measure the elastic properties of plaques and vessels is significant in clinical diagnosis, particularly for detecting a vulnerable plaque. A novel concept of combining intravascular ultrasound (IVUS) imaging and acoustic radiation force impulse (ARFI) imaging has recently been proposed. This method has potential in elastography for distinguishing between the stiffness of plaques and arterial vessel walls. However, the intensity of the acoustic radiation force requires calibration as a standard for the further development of an ARFI-IVUS imaging device that could be used in clinical applications. In this study, a dual-frequency transducer with 11MHz and 48MHz was used to measure the association between the biological tissue displacement and the applied acoustic radiation force. The output intensity of the acoustic radiation force generated by the pushing element ranged from 1.8 to 57.9mW/cm(2), as measured using a calibrated hydrophone. The results reveal that all of the acoustic intensities produced by the transducer in the experiments were within the limits specified by FDA regulations and could still displace the biological tissues. Furthermore, blood clots with different hematocrits, which have elastic properties similar to the lipid pool of plaques, with stiffness ranging from 0.5 to 1.9kPa could be displaced from 1 to 4μm, whereas the porcine arteries with stiffness ranging from 120 to 291kPa were displaced from 0.4 to 1.3μm when an acoustic intensity of 57.9mW/cm(2) was used. The in vitro ARFI images of the artery with a blood clot and artificial arteriosclerosis showed a clear distinction of the stiffness distributions of the vessel wall. All the results reveal that ARFI-IVUS imaging has the potential to distinguish the elastic properties of plaques and vessels. Moreover, the acoustic intensity used in ARFI imaging has been experimentally quantified. Although the size of this two-element transducer is unsuitable for IVUS imaging, the

  7. A time-resolved imaging and electrical study on a high current atmospheric pressure spark discharge

    NASA Astrophysics Data System (ADS)

    Palomares, J. M.; Kohut, A.; Galbács, G.; Engeln, R.; Geretovszky, Zs.

    2015-12-01

    We present a time-resolved imaging and electrical study of an atmospheric pressure spark discharge. The conditions of the present study are those used for nanoparticle generation in spark discharge generator setups. The oscillatory bipolar spark discharge was generated between two identical Cu electrodes in different configurations (cylindrical flat-end or tipped-end geometries, electrode gap from 0.5 to 4 mm), in a controlled co-axial N2 flow, and was supplied by a high voltage capacitor. Imaging data with nanosecond time resolution were collected using an intensified CCD camera. This data were used to study the time evolution of plasma morphology, total light emission intensity, and the rate of plasma expansion. High voltage and high current probes were employed to collect electrical data about the discharge. The electrical data recorded allowed, among others, the calculation of the equivalent resistance and inductance of the circuit, estimations for the energy dissipated in the spark gap. By combining imaging and electrical data, observations could be made about the correlation of the evolution of total emitted light and the dissipated power. It was also observed that the distribution of light emission of the plasma in the spark gap is uneven, as it exhibits a "hot spot" with an oscillating position in the axial direction, in correlation with the high voltage waveform. The initial expansion rate of the cylindrical plasma front was found to be supersonic; thus, the discharge releases a strong shockwave. Finally, the results on equivalent resistance and channel expansion are comparable to those of unipolar arcs. This shows the spark discharge has a similar behavior to the arc regime during the conductive phase and until the current oscillations stop.

  8. Acoustic Radiation Force Impulse Imaging for Noninvasive Evaluation of Renal Parenchyma Elasticity: Preliminary Findings

    PubMed Central

    Xu, Hui-Xiong; Peng, Ai; Zhang, Yi-Feng; Liu, Lin-Na

    2013-01-01

    Objective To evaluate the diagnostic value of acoustic radiation force impulse (ARFI) to test the elasticity of renal parenchyma by measuring the shear wave velocity (SWV) which might be used to detect chronic kidney disease (CKD). Methods 327 healthy volunteers and 64 CKD patients were enrolled in the study. The potential influencing factors and measurement reproducibility were evaluated in the healthy volunteers. Correlations between SWV and laboratory tests were analyzed in CKD patients.?Receiver-operating characteristic curve (ROC) analyses were performed to assess the diagnostic performance of ARFI. Results The SWV of healthy volunteers correlated significantly to age (r = −0.22, P<0.001, n = 327) and differed significantly between men and women (2.06±0.48 m/s vs. 2.2±0.52 m/s, P = 0.018, n = 327). However, it did not correlate significantly to height, weight, body mass index, waistline, kidney dimension and the depth for SWV measurement (n = 30). Inter- and intraobserver agreement expressed as intraclass coefficient correlation were 0.64 (95% CI: 0.13 to 0.82, P = 0.011) and 0.6 (95% CI: 0.31 to 0.81, P = 0.001) (n = 40). The mean SWV in healthy volunteers was 2.15±0.51 m/s, while was 1.81±0.43 m/s, 1.79±0.29 m/s, 1.81±0.44 m/s, 1.64±0.55 m/s, and 1.36±0.17 m/s for stage 1, 2, 3, 4 and 5 in CKD patients respectively. The SWV was significantly higher for healthy volunteers compared with each stage in CKD patients. ARFI could not predict the different stages of CKD except stage 5. In CKD patients, SWV correlated to e-GFR (r = 0.3, P = 0.018), to urea nitrogen (r =  −0.3, P = 0.016), and to creatinine (r =  −0.41, P = 0.001). ROC analyses indicated that the area under the ROC curve was 0.752 (95% CI: 0.704 to 0.797) (P<0.001). The cut-off value for predicting CKD was 1.88 m/s (sensitivity 71.87% and specificity 69.69%). Conclusion ARFI may be a potentially useful tool in detecting CKD. PMID

  9. Toward global mapping of river discharge using satellite images and at-many-stations hydraulic geometry

    PubMed Central

    Gleason, Colin J.; Smith, Laurence C.

    2014-01-01

    Rivers provide critical water supply for many human societies and ecosystems, yet global knowledge of their flow rates is poor. We show that useful estimates of absolute river discharge (in cubic meters per second) may be derived solely from satellite images, with no ground-based or a priori information whatsoever. The approach works owing to discovery of a characteristic scaling law uniquely fundamental to natural rivers, here termed a river’s at-many-stations hydraulic geometry. A first demonstration using Landsat Thematic Mapper images over three rivers in the United States, Canada, and China yields absolute discharges agreeing to within 20–30% of traditional in situ gauging station measurements and good tracking of flow changes over time. Within such accuracies, the door appears open for quantifying river resources globally with repeat imaging, both retroactively and henceforth into the future, with strong implications for water resource management, food security, ecosystem studies, flood forecasting, and geopolitics. PMID:24639551

  10. Toward global mapping of river discharge using satellite images and at-many-stations hydraulic geometry.

    PubMed

    Gleason, Colin J; Smith, Laurence C

    2014-04-01

    Rivers provide critical water supply for many human societies and ecosystems, yet global knowledge of their flow rates is poor. We show that useful estimates of absolute river discharge (in cubic meters per second) may be derived solely from satellite images, with no ground-based or a priori information whatsoever. The approach works owing to discovery of a characteristic scaling law uniquely fundamental to natural rivers, here termed a river's at-many-stations hydraulic geometry. A first demonstration using Landsat Thematic Mapper images over three rivers in the United States, Canada, and China yields absolute discharges agreeing to within 20-30% of traditional in situ gauging station measurements and good tracking of flow changes over time. Within such accuracies, the door appears open for quantifying river resources globally with repeat imaging, both retroactively and henceforth into the future, with strong implications for water resource management, food security, ecosystem studies, flood forecasting, and geopolitics.

  11. Ground truth for SIR-B images obtained by SIR system 8 impulse radar

    NASA Technical Reports Server (NTRS)

    Ulriksen, P.; Ottersten, H.; Borg, C. G.; Axelsson, S.; Ekengren, B.

    1984-01-01

    Verification of suspected penetration by means of three dimensional information on the features in the SIR-B images will be investigated. The Great Alvar is a well documented area, especially in geology and ecology, and should provide a good opportunity to evaluate the data.

  12. Assessment of liver fibrosis with 2-D shear wave elastography in comparison to transient elastography and acoustic radiation force impulse imaging in patients with chronic liver disease.

    PubMed

    Gerber, Ludmila; Kasper, Daniela; Fitting, Daniel; Knop, Viola; Vermehren, Annika; Sprinzl, Kathrin; Hansmann, Martin L; Herrmann, Eva; Bojunga, Joerg; Albert, Joerg; Sarrazin, Christoph; Zeuzem, Stefan; Friedrich-Rust, Mireen

    2015-09-01

    Two-dimensional shear wave elastography (2-D SWE) is an ultrasound-based elastography method integrated into a conventional ultrasound machine. It can evaluate larger regions of interest and, therefore, might be better at determining the overall fibrosis distribution. The aim of this prospective study was to compare 2-D SWE with the two best evaluated liver elastography methods, transient elastography and acoustic radiation force impulse (point SWE using acoustic radiation force impulse) imaging, in the same population group. The study included 132 patients with chronic hepatopathies, in which liver stiffness was evaluated using transient elastography, acoustic radiation force impulse imaging and 2-D SWE. The reference methods were liver biopsy for the assessment of liver fibrosis (n = 101) and magnetic resonance imaging/computed tomography for the diagnosis of liver cirrhosis (n = 31). No significant difference in diagnostic accuracy, assessed as the area under the receiver operating characteristic curve (AUROC), was found between the three elastography methods (2-D SWE, transient elastography, acoustic radiation force impulse imaging) for the diagnosis of significant and advanced fibrosis and liver cirrhosis in the "per protocol" (AUROCs for fibrosis stages ≥2: 0.90, 0.95 and 0.91; for fibrosis stage [F] ≥3: 0.93, 0.95 and 0.94; for F = 4: 0.92, 0.96 and 0.92) and "intention to diagnose" cohort (AUROCs for F ≥2: 0.87, 0.92 and 0.91; for F ≥3: 0.91, 0.93 and 0.94; for F = 4: 0.88, 0.90 and 0.89). Therefore, 2-D SWE, ARFI imaging and transient elastography seem to be comparably good methods for non-invasive assessment of liver fibrosis.

  13. Television image of a large upward electrical discharge above a thunderstorm system.

    PubMed

    Franz, R C; Nemzek, R J; Winckler, J R

    1990-07-06

    An image of an unusual luminous electrical discharge over a thunderstorm 250 kilometers from the observing site has been obtained with a low-light-level television camera. The discharge began at the cloud tops at 14 kilometers and extended into the clear air 20 kilometers higher. The image, which had a duration of less than 30 milliseconds,resembled two jets or fountains and was probably caused by two localizd electric charge concentrations at the cloud tops. Large upward discharges may create a hazard for aircraft and rocket launches and, by penetrating into the ionosphere, may initiate whistler waves and other effects on a magnetospheric scale. Such upward electrical discharges may account for unexplained photometric observations of distant lightning events that showed a low rise rate of the luminous pulse and no electromagnetic sferic pulse of the type that accompanies cloud-to-earth lightning strokes. An unusually high rate of such photometric events was recorded during the night of 22 to 23 September 1989 during a storm associated with hurricane Hugo.

  14. An adaptive switching filter based on approximated variance for detection of impulse noise from color images.

    PubMed

    Pritamdas, K; Singh, Kh Manglem; Singh, L Lolitkumar

    2016-01-01

    A new adaptive switching algorithm is presented where two adaptive filters are switched correspondingly for lower and higher noise ratio of the image. An adaptive center weighted vector median filter is used for the lower noise ratio whereas for higher noise ratio the noisy pixels are detected based on the comparison of the difference between the mean of the vector pixels in the window and the approximated variance of the vector pixels in the window. Then the window comprising the detected noisy pixel is further considered where the pixels are given exponential weights according to their similarity to the other neighboring pixels, spatially and radio metrically. The noisy pixels are then replaced by the weighted average of the pixels within the window. The filter is able to preserve higher signal content in the higher noise ratio as compared to other robust filters in comparison. With a little high in computational complexity, this technique performs well both in lower and higher noise ratios. Simulation results on various RGB images show that the proposed algorithm outperforms many other existing nonlinear filters in terms of preservation of edges and fine details.

  15. Gas discharge visualization: an imaging and modeling tool for medical biometrics.

    PubMed

    Kostyuk, Nataliya; Cole, Phyadragren; Meghanathan, Natarajan; Isokpehi, Raphael D; Cohly, Hari H P

    2011-01-01

    The need for automated identification of a disease makes the issue of medical biometrics very current in our society. Not all biometric tools available provide real-time feedback. We introduce gas discharge visualization (GDV) technique as one of the biometric tools that have the potential to identify deviations from the normal functional state at early stages and in real time. GDV is a nonintrusive technique to capture the physiological and psychoemotional status of a person and the functional status of different organs and organ systems through the electrophotonic emissions of fingertips placed on the surface of an impulse analyzer. This paper first introduces biometrics and its different types and then specifically focuses on medical biometrics and the potential applications of GDV in medical biometrics. We also present our previous experience with GDV in the research regarding autism and the potential use of GDV in combination with computer science for the potential development of biological pattern/biomarker for different kinds of health abnormalities including cancer and mental diseases.

  16. Gas Discharge Visualization: An Imaging and Modeling Tool for Medical Biometrics

    PubMed Central

    Kostyuk, Nataliya; Cole, Phyadragren; Meghanathan, Natarajan; Isokpehi, Raphael D.; Cohly, Hari H. P.

    2011-01-01

    The need for automated identification of a disease makes the issue of medical biometrics very current in our society. Not all biometric tools available provide real-time feedback. We introduce gas discharge visualization (GDV) technique as one of the biometric tools that have the potential to identify deviations from the normal functional state at early stages and in real time. GDV is a nonintrusive technique to capture the physiological and psychoemotional status of a person and the functional status of different organs and organ systems through the electrophotonic emissions of fingertips placed on the surface of an impulse analyzer. This paper first introduces biometrics and its different types and then specifically focuses on medical biometrics and the potential applications of GDV in medical biometrics. We also present our previous experience with GDV in the research regarding autism and the potential use of GDV in combination with computer science for the potential development of biological pattern/biomarker for different kinds of health abnormalities including cancer and mental diseases. PMID:21747817

  17. A New Image Based Approach to Measure Discharge and Soil Saturation

    NASA Astrophysics Data System (ADS)

    Kaplan, Nils; Weiler, Markus; Blume, Theresa

    2016-04-01

    Discharge measurements are crucial for most hydrological studies. It is common to monitor discharge by recording water level and calculate the actual discharge using a rating curve that has been previously determined for varying flow conditions. Bubble and float gauges as well as radar based gauges are frequently used to measure water level. Recently particle image velocimetry (PIV) approaches have become more attractive due to continuous improvement of sensors and computing power. Standard cameras can be easily usable and cheap monitoring devices for discharge measurement. The combination of a camera and a staff gauge has been proved to be suitable for hydrological monitoring in several studies and is promoted as redundant backup as well as independent system. Our new image based system offers the possibility to measure water velocity and soil saturation in addition to water level. We use a commercial wildlife camera with sensors in the visible and infrared spectrum, allowing for day and night images. The system can be used for three purposes. (1) Water level measurement with a specifically built gauging plate. (2) A carbon fiber stick installed instream allows water velocity measurements. Water velocity can be derived from the bending of the carbon fiber under water pressure which is proportional to the water velocity and water level. Hence we can derive a rating curve between bending angle of the carbon fiber stick and the water velocity. Therefore we can constantly measure the water velocity and do not depend on traditional rating curves. (3) Soil water saturation is measured by perforated PVC bottles that enable water in- and outflow. Rising water level in the PVC-bottle will lift an integrated floating body that pushes up a detection marker visible for the camera above the ground. The measurement system is tested for monitoring intermittent streams in the Attert basin in Luxemburg linking the dynamics of the stream network extent to the surface connectivity

  18. Low Pretreatment Acoustic Radiation Force Impulse Imaging (ARFI) Values Predict Sustained Virological Response in Antiviral Hepatitis C Virus (HCV) Therapy

    PubMed Central

    Zopf, Steffen; Rösch, Lara; Konturek, Peter C.; Goertz, Ruediger S.; Neurath, Markus F.; Strobel, Deike

    2016-01-01

    Background Non-invasive procedures such as acoustic radiation force impulse imaging (ARFI) shear-wave elastography are currently used for the assessment of liver fibrosis. In the course of chronic hepatitis C, significant liver fibrosis or cirrhosis develops in approximately 25% of patients, which is a negative predictor of antiviral treatment response. Cirrhosis can be prevented by successful virus elimination. In this prospective study, a pretreatment ARFI cutoff value of 1.5 m/s was evaluated in relation to sustained virological response to anti-HCV therapy. Material/Methods In 23 patients with chronic hepatitis C, liver stiffness was examined with ARFI at defined times before and under antiviral triple therapy (peginterferon, ribavirin in combination with a first-generation protease inhibitor, and telaprevir or boceprevir). Patients were stratified into 2 groups based on pretreatment ARFI values (<1.5 m/s and ≥1.5 m/s) for the assessment of virological response. Results The liver stiffness at baseline for all patients was 1.57±0.79 m/s (ARFI median ± standard deviation; margin: 0.81 m/s to 3.45 m/s). At week 4 of triple therapy, patients with low pretreatment ARFI values had higher rates of HCV-RNA negativity (69% vs. 43%), reflecting an early rapid virological response (eRVR). Sustained virological response (SVR) was found in 75% (12/16) of patients with an ARFI value <1.5 m/s and only 57% (4/7) of patients with ARFI value ≥1.5 m/s. Conclusions Patients with chronic hepatitis C and pretreatment ARFI <1.5 m/s showed earlier virus elimination and better response to treatment. PMID:27690214

  19. Three-Dimensional ISAR Imaging Method for High-Speed Targets in Short-Range Using Impulse Radar Based on SIMO Array

    PubMed Central

    Zhou, Xinpeng; Wei, Guohua; Wu, Siliang; Wang, Dawei

    2016-01-01

    This paper proposes a three-dimensional inverse synthetic aperture radar (ISAR) imaging method for high-speed targets in short-range using an impulse radar. According to the requirements for high-speed target measurement in short-range, this paper establishes the single-input multiple-output (SIMO) antenna array, and further proposes a missile motion parameter estimation method based on impulse radar. By analyzing the motion geometry relationship of the warhead scattering center after translational compensation, this paper derives the receiving antenna position and the time delay after translational compensation, and thus overcomes the shortcomings of conventional translational compensation methods. By analyzing the motion characteristics of the missile, this paper estimates the missile’s rotation angle and the rotation matrix by establishing a new coordinate system. Simulation results validate the performance of the proposed algorithm. PMID:26978372

  20. Three-Dimensional ISAR Imaging Method for High-Speed Targets in Short-Range Using Impulse Radar Based on SIMO Array.

    PubMed

    Zhou, Xinpeng; Wei, Guohua; Wu, Siliang; Wang, Dawei

    2016-03-11

    This paper proposes a three-dimensional inverse synthetic aperture radar (ISAR) imaging method for high-speed targets in short-range using an impulse radar. According to the requirements for high-speed target measurement in short-range, this paper establishes the single-input multiple-output (SIMO) antenna array, and further proposes a missile motion parameter estimation method based on impulse radar. By analyzing the motion geometry relationship of the warhead scattering center after translational compensation, this paper derives the receiving antenna position and the time delay after translational compensation, and thus overcomes the shortcomings of conventional translational compensation methods. By analyzing the motion characteristics of the missile, this paper estimates the missile's rotation angle and the rotation matrix by establishing a new coordinate system. Simulation results validate the performance of the proposed algorithm.

  1. Wavelength Scanning with a Tilting Interference Filter for Glow-Discharge Elemental Imaging.

    PubMed

    Storey, Andrew P; Ray, Steven J; Hoffmann, Volker; Voronov, Maxim; Engelhard, Carsten; Buscher, Wolfgang; Hieftje, Gary M

    2016-11-21

    Glow discharges have long been used for depth profiling and bulk analysis of solid samples. In addition, over the past decade, several methods of obtaining lateral surface elemental distributions have been introduced, each with its own strengths and weaknesses. Challenges for each of these techniques are acceptable optical throughput and added instrumental complexity. Here, these problems are addressed with a tilting-filter instrument. A pulsed glow discharge is coupled to an optical system comprising an adjustable-angle tilting filter, collimating and imaging lenses, and a gated, intensified charge-coupled device (CCD) camera, which together provide surface elemental mapping of solid samples. The tilting-filter spectrometer is instrumentally simpler, produces less image distortion, and achieves higher optical throughput than a monochromator-based instrument, but has a much more limited tunable spectral range and poorer spectral resolution. As a result, the tilting-filter spectrometer is limited to single-element or two-element determinations, and only when the target spectral lines fall within an appropriate spectral range and can be spectrally discerned. Spectral interferences that result from heterogeneous impurities can be flagged and overcome by observing the spatially resolved signal response across the available tunable spectral range. The instrument has been characterized and evaluated for the spatially resolved analysis of glow-discharge emission from selected but representative samples.

  2. Particle visualization in high-power impulse magnetron sputtering. I. 2D density mapping

    SciTech Connect

    Britun, Nikolay Palmucci, Maria; Konstantinidis, Stephanos; Snyders, Rony

    2015-04-28

    Time-resolved characterization of an Ar-Ti high-power impulse magnetron sputtering discharge has been performed. This paper deals with two-dimensional density mapping in the discharge volume obtained by laser-induced fluorescence imaging. The time-resolved density evolution of Ti neutrals, singly ionized Ti atoms (Ti{sup +}), and Ar metastable atoms (Ar{sup met}) in the area above the sputtered cathode is mapped for the first time in this type of discharges. The energetic characteristics of the discharge species are additionally studied by Doppler-shift laser-induced fluorescence imaging. The questions related to the propagation of both the neutral and ionized discharge particles, as well as to their spatial density distributions, are discussed.

  3. Characterization of a vacuum-arc discharge in tin vapor using time-resolved plasma imaging and extreme ultraviolet spectrometry.

    PubMed

    Kieft, E R; van der Mullen, J J A M; Kroesen, G M W; Banine, V; Koshelev, K N

    2005-02-01

    Discharge sources in tin vapor have recently been receiving increased attention as candidate extreme ultraviolet (EUV) light sources for application in semiconductor lithography, because of their favorable spectrum near 13.5 nm. In the ASML EUV laboratory, time-resolved pinhole imaging in the EUV and two-dimensional imaging in visible light have been applied for qualitative characterization of the evolution of a vacuum-arc tin vapor discharge. An EUV spectrometer has been used to find the dominant ionization stages of tin as a function of time during the plasma evolution of the discharge.

  4. Dynamic Electrical Source Imaging (DESI) of Seizures and Interictal Epileptic Discharges Without Ensemble Averaging

    PubMed Central

    Erem, Burak; Hyde, Damon E.; Peters, Jurriaan M.; Duffy, Frank H.; Warfield, Simon K.

    2016-01-01

    We propose an algorithm for electrical source imaging of epileptic discharges that takes a data-driven approach to regularizing the dynamics of solutions. The method is based on linear system identification on short time segments, combined with a classical inverse solution approach. Whereas ensemble averaging of segments or epochs discards inter-segment variations by averaging across them, our approach explicitly models them. Indeed, it may even be possible to avoid the need for the time-consuming process of marking epochs containing discharges altogether. We demonstrate that this approach can produce both stable and accurate inverse solutions in experiments using simulated data and real data from epilepsy patients. In an illustrative example, we show that we are able to image propagation using this approach. We show that when applied to imaging seizure data, our approach reproducibly localized frequent seizure activity to within the margins of surgeries that led to patients’ seizure freedom. The same approach could be used in the planning of epilepsy surgeries, as a way to localize potentially epileptogenic tissue that should be resected. PMID:27479957

  5. Pāhoehoe flow cooling, discharge, and coverage rates from thermal image chronometry

    USGS Publications Warehouse

    Dehn, Jonathan; Hamilton, Christopher M.; Harris, A. J. L.; Herd, Richard A.; James, M.R.; Lodato, Luigi; Steffke, Andrea

    2007-01-01

    Theoretically- and empirically-derived cooling rates for active pāhoehoe lava flows show that surface cooling is controlled by conductive heat loss through a crust that is thickening with the square root of time. The model is based on a linear relationship that links log(time) with surface cooling. This predictable cooling behavior can be used assess the age of recently emplaced sheet flows from their surface temperatures. Using a single thermal image, or image mosaic, this allows quantification of the variation in areal coverage rates and lava discharge rates over 48 hour periods prior to image capture. For pāhoehoe sheet flow at Kīlauea (Hawai`i) this gives coverage rates of 1–5 m2/min at discharge rates of 0.01–0.05 m3/s, increasing to ∼40 m2/min at 0.4–0.5 m3/s. Our thermal chronometry approach represents a quick and easy method of tracking flow advance over a three-day period using a single, thermal snap-shot.

  6. Stream Discharge Measurement Using A Large-Scale Particle Image Velocimetry Prototype

    NASA Astrophysics Data System (ADS)

    Harpold, A. A.; Mostaghimi, S.

    2004-12-01

    Good water management is founded on accurate open-channel flow measurements. New technology for measuring discharge in streams and rivers has been pursued due to concerns about safety, accuracy, and costs of traditional methods. Large-Scale Particle Image Velocimetry (LSPIV) is an emerging technology for measuring discharge in streams and rivers. LSPIV is a system capable of measuring velocity fields by collecting and analyzing recorded images of the flow field. The LSPIV system tracks the movement of `tracers' through successive images using statistical correspondence. Cross-correlation algorithms divide the image into small interrogation areas; each producing one displacement vector. The surface velocity field can be used to estimate discharge based on the channel bathymetry. Use of LSPIV for flow measurements in low-order streams has several advantages. LSPIV is not as labor intensive and does not present the safety concerns of the conventional methods during high flow events. Another promise for LSPIV is remote monitoring applications, which could also reduce labor and data management costs. The scheme used in this study for the development of LSPIV follows a logical progression: assimilate current knowledge, develop methods and acquire equipment, conduct laboratory and field experiments for `proof-of-concept', and refine the methods to decrease costs and increase usability. A laboratory prototype was developed and tested in a flume, with good results. The experiment evaluated the LSPIV prototype and a Marsh-McBirney flow meter against the flume manometer. Several conclusions were made from the statistical analysis. The Froude number affects the accuracy of the Marsh-McBirney flow meter and the LSPIV prototype. Therefore, future applications may wish to use an adaptive method to determine input parameters based on flow conditions. The LSPIV prototype produced poor flow measurements at camera angles above a 30 degree oblique angle. Therefore, field applications

  7. Anatomy of a SAR impulse response.

    SciTech Connect

    Doerry, Armin Walter

    2007-08-01

    A principal measure of Synthetic Aperture Radar (SAR) image quality is the manifestation in the SAR image of a spatial impulse, that is, the SAR's Impulse Response (IPR). IPR requirements direct certain design decisions in a SAR. Anomalies in the IPR can point to specific anomalous behavior in the radar's hardware and/or software.

  8. The Rightful Role of MRI after Negative Conventional Imaging in the Management of Bloody Nipple Discharge.

    PubMed

    Sanders, Linda M; Daigle, Megan

    2016-01-01

    Nipple discharge is a frequent presenting complaint at breast clinics. Bloody nipple discharge (BND) has the highest risk of malignancy, albeit low. If mammogram and ultrasound are unrevealing, central duct excision (CDE) has been considered the gold standard in its management. Magnetic resonance imaging (MRI) has been widely confirmed as a highly sensitive test for detection of breast cancer, with an accompanying high negative predictive value. This article presents a retrospective review of patients with BND and negative conventional imaging, comparing outcome of patients who went directly to CDE without MRI to those patients who underwent preoperative MRI. Of 115 patients who underwent mammography and US alone prior to CDE, eight cancers were detected (seven ductal carcinoma in situ [DCIS] and 1 IDC, 7 mm [T1b]; incidence: 7%). Of 85 patients who underwent conventional imaging followed by MRI prior to surgery, eight cancers were detected (all DCIS; incidence: 9.4%), seven of which were identified by MRI. The one false-negative MRI had subtle findings which, in retrospect, were misinterpreted; however, a clinically apparent nipple lesion prompted surgical biopsy. Of 56 patients with a negative or benign MRI, CDE was negative for malignancy in all but that one patient. Sensitivity and specificity were 87.5%/71.4%. Positive predictive value and negative predictive value (NPV) were 24.1%/98.2%. MRI should be performed in all patients with BND and negative conventional imaging. The extremely high NPV of MRI suggests that a negative study could obviate CDE in most patients unless overriding clinical factors prevail.

  9. Microwave Imaging of a Hot Flux Rope Structure during the Pre-impulsive Stage of an Eruptive M7.7 Solar Flare

    NASA Astrophysics Data System (ADS)

    Wu, Zhao; Chen, Yao; Huang, Guangli; Nakajima, Hiroshi; Song, Hongqiang; Melnikov, Victor; Liu, Wei; Li, Gang; Chandrashekhar, Kalugodu; Jiao, Fangran

    2016-04-01

    Corona structures and processes during the pre-impulsive stage of solar eruption are crucial to understanding the physics leading to the subsequent explosive energy release. Here we present the first microwave imaging study of a hot flux rope structure during the pre-impulsive stage of an eruptive M7.7 solar flare, with the Nobeyama Radioheliograph at 17 GHz. The flux rope is also observed by the SDO/AIA in its hot passbands of 94 and 131 Å. In the microwave data, it is revealed as an overall arcade-like structure consisting of several intensity enhancements bridged by generally weak emissions, with brightness temperatures (T B) varying from ˜10,000 K to ˜20,000 K. Locations of microwave intensity enhancements along the structure remain relatively fixed at certain specific parts of the flux rope, indicating that the distribution of emitting electrons is affected by the large-scale magnetic configuration of the twisted flux rope. Wavelet analysis shows a pronounced 2 minute period of the microwave T B variation during the pre-impulsive stage of interest. The period agrees well with that reported for AIA sunward-contracting loops and upward ejective plasmoids (suggested to be reconnection outflows). This suggests that both periodicities are controlled by the same reconnection process that takes place intermittently at a 2 minute timescale. We infer that at least a part of the emission is excited by non-thermal energetic electrons via the gyro-synchrotron mechanism. The study demonstrates the potential of microwave imaging in exploring the flux rope magnetic geometry and relevant reconnection process during the onset of solar eruption.

  10. MICROWAVE IMAGING OF A HOT FLUX ROPE STRUCTURE DURING THE PRE-IMPULSIVE STAGE OF AN ERUPTIVE M7.7 SOLAR FLARE

    SciTech Connect

    Wu, Zhao; Chen, Yao; Song, Hongqiang; Chandrashekhar, Kalugodu; Jiao, Fangran; Huang, Guangli; Nakajima, Hiroshi; Melnikov, Victor; Liu, Wei; Li, Gang

    2016-04-01

    Corona structures and processes during the pre-impulsive stage of solar eruption are crucial to understanding the physics leading to the subsequent explosive energy release. Here we present the first microwave imaging study of a hot flux rope structure during the pre-impulsive stage of an eruptive M7.7 solar flare, with the Nobeyama Radioheliograph at 17 GHz. The flux rope is also observed by the SDO/AIA in its hot passbands of 94 and 131 Å. In the microwave data, it is revealed as an overall arcade-like structure consisting of several intensity enhancements bridged by generally weak emissions, with brightness temperatures (T{sub B}) varying from ∼10,000 K to ∼20,000 K. Locations of microwave intensity enhancements along the structure remain relatively fixed at certain specific parts of the flux rope, indicating that the distribution of emitting electrons is affected by the large-scale magnetic configuration of the twisted flux rope. Wavelet analysis shows a pronounced 2 minute period of the microwave T{sub B} variation during the pre-impulsive stage of interest. The period agrees well with that reported for AIA sunward-contracting loops and upward ejective plasmoids (suggested to be reconnection outflows). This suggests that both periodicities are controlled by the same reconnection process that takes place intermittently at a 2 minute timescale. We infer that at least a part of the emission is excited by non-thermal energetic electrons via the gyro-synchrotron mechanism. The study demonstrates the potential of microwave imaging in exploring the flux rope magnetic geometry and relevant reconnection process during the onset of solar eruption.

  11. An analysis on effecting factors of ultra-violet imaging appliance in corona discharge

    NASA Astrophysics Data System (ADS)

    Han, Xiao; Yang, Ning; Yuan, Shuai; Bi, Jiangang

    2014-11-01

    In this paper, the operating principle of daylight UV imagers was introduced first, emphasizing the SBUV(solar blind UV) technology, which utilizes the fact that ultra violet between 240nm~280nm is being absorbed by the ozone so that signals detected on earth in this spectral range originate on earth. And then several influencing factors were explained, including observation distance, observing angle, imager gain settings and environmental conditions. Experimental data measured in the UHV(ultra high-voltage) DC converter station in Changzhi, Shanxi, China were analyzed using SRA(single regression analysis) method, and mathematical equations with acceptable deviation were calculated, with simulating curves plotted. The results show that environmental conditions including humidity and temperature, observation distance and imager gain settings all contribute to the measuring result, exhibiting as exponential function and convex function respectively. Concluded from the above analysis and calculation, observing conditions of a clear observing angle at the same observation distance with mediate gain settings on days of low humidity were recommended. This conclusion may guide further ultra-violet imaging appliance in high-voltage electrical devices corona discharge sensing.

  12. In vivo feasibility case study for evaluating abdominal aortic aneurysm tissue properties and rupture potential using acoustic radiation force impulse imaging.

    PubMed

    Tierney, Aine P; Callanan, Anthony; McGloughlin, Timothy M

    2011-04-01

    An abdominal aortic aneurysm (AAA) is defined as a permanent and irreversible localized dilatation of the abdominal aorta. A reliable, non-invasive method to assess the wall mechanics of an aneurysm may provide additional information regarding their susceptibility to rupture. Acoustic radiation force impulse (ARFI) imaging is a phenomenon associated with the propagation of acoustic waves in attenuating media. This study was a preliminary evaluation to explore the feasibility of using ARFI imaging to examine an AAA in vivo. A previously diagnosed in vivo aneurysm case study was imaged to demonstrate the viability of excitation of the abdominal aorta using ARFI imaging. Ex vivo experiments were used to assess an artificially induced aneurysm to establish its development and whether ARFI was able to capture the mechanical changes during artificial aneurysm formation. A combination of in vivo and ex vivo results demonstrated a proposed hypothesis of estimation of the tissue's stiffness properties. The study details a method for non-invasive rupture potential prediction of AAAs using patient-specific moduli to generate a physiological stiffness rupture potential index (PSRPI) of the AAA. Clinical feasibility of ARFI imaging as an additional surgical tool to interrogate AAAs was verified and methods to utilize this data as a diagnostic tool was demonstrated with the PSRPI.

  13. Dopamine-agonists and impulsivity in Parkinson's disease: impulsive choices vs. impulsive actions.

    PubMed

    Antonelli, Francesca; Ko, Ji Hyun; Miyasaki, Janis; Lang, Anthony E; Houle, Sylvain; Valzania, Franco; Ray, Nicola J; Strafella, Antonio P

    2014-06-01

    The control of impulse behavior is a multidimensional concept subdivided into separate subcomponents, which are thought to represent different underlying mechanisms due to either disinhibitory processes or poor decision-making. In patients with Parkinson's disease (PD), dopamine-agonist (DA) therapy has been associated with increased impulsive behavior. However, the relationship among these different components in the disease and the role of DA is not well understood. In this imaging study, we investigated in PD patients the effects of DA medication on patterns of brain activation during tasks testing impulsive choices and actions. Following overnight withdrawal of antiparkinsonian medication, PD patients were studied with a H2 ((15)) O PET before and after administration of DA (1 mg of pramipexole), while they were performing the delay discounting task (DDT) and the GoNoGo Task (GNG). We observed that pramipexole augmented impulsivity during DDT, depending on reward magnitude and activated the medial prefrontal cortex and posterior cingulate cortex and deactivated ventral striatum. In contrast, the effect of pramipexole during the GNG task was not significant on behavioral performance and involved different areas (i.e., lateral prefrontal cortex). A voxel-based correlation analysis revealed a significant negative correlation between the discounting value (k) and the activation of medial prefrontal cortex and posterior cingulate suggesting that more impulsive patients had less activation in those cortical areas. Here we report how these different subcomponents of inhibition/impulsivity are differentially sensitive to DA treatment with pramipexole influencing mainly the neural network underlying impulsive choices but not impulsive action.

  14. Sensitivity study of large-scale particle image velocimetry measurement of river discharge using numerical simulation

    NASA Astrophysics Data System (ADS)

    Hauet, Alexandre; Creutin, Jean-Dominique; Belleudy, Philippe

    2008-01-01

    block performs a classical LSPIV analysis, including geometric transformation of the images, PIV analysis to obtain a surface velocity field, and discharge computation. We tried to keep a good balance between the different blocks of the simulator (i.e. not to make one component much more sophisticated than the others). The simulator was partly tested during the development of its different blocks, and then globally validated. It reproduced well the variability observed in the field LSPIV experiments conducted with the real-time continuous system of Hauet et al. [Hauet, A., Kruger, A., Krajewski, W., Bradley, A., Muste, M., Creutin, J.D., Wilson, M., 2008. Experimental system for real-time discharge estimation using an image-based method. Journal of Hydrologic Engineering]. The simulator can also be used to check different scenarios and to assess relative importance of the different sources of error. With two examples, we illustrate this capability of the simulator to assess the relative weight of a given error source and to test a new configuration of measurement.

  15. Value of acoustic radiation force impulse imaging elastography for non-invasive evaluation of patients with nonalcoholic fatty liver disease.

    PubMed

    Fierbinteanu Braticevici, Carmen; Sporea, Ioan; Panaitescu, Eugenia; Tribus, Laura

    2013-11-01

    The goals of the work described here were to evaluate the clinical utility of acoustic radiation force impulse (ARFI) elastography in differentiating non-alcoholic fatty liver disease (NAFLD) histologic subtypes and to determine if ARFI elastography measurements correlate with the severity of liver fibrosis. We compared ARFI elastography measurements with clinical, biologic and histologic features (simple steatosis or steatohepatitis) in 64 patients with histologically proven NAFLD. ARFI elastography is suitable for distinguishing patients with non-alcoholic steatohepatitis from those with simple steatosis, with an area under the receiver operating characteristic curve (AUROC) of 0.867 (95% confidence interval = 0.782-0.953). There was a highly significant correlation (r = 0.843) between ARFI elastography measurements and fibrosis (p < 0.001). In patients with non-alcoholic steatohepatitis, the diagnostic performance of ARFI elastography in predicting significant fibrosis (F ≥ 2) had an AUROC of 0.944. ARFI elastography better predicted F = 4 fibrosis (AUROC = 0.984). In conclusion, ARFI elastography is a promising method for differentiating patients with non-alcoholic steatohepatitis from patients with simple steatosis and can also predict significant fibrosis in these patients.

  16. Ex vivo study of acoustic radiation force impulse imaging elastography for evaluation of rat liver with steatosis.

    PubMed

    Guo, Yanrong; Dong, Changfeng; Lin, Haoming; Zhang, Xinyu; Wen, Huiying; Shen, Yuanyuan; Wang, Tianfu; Chen, Siping; Liu, Yingxia; Chen, Xin

    2017-02-01

    Nonalcoholic fatty liver disease (NAFLD) is one of the most common liver diseases in developed countries. Accurate, noninvasive tests for diagnosing NAFLD are urgently needed. The goals of this study were to evaluate the utility of acoustic radiation force impulse (ARFI) elastography for determining the severity grade of steatosis in rat livers, and to investigate the changes in various histologic and biochemical characteristics. Steatosis was induced in the livers of 57 rats by gavage feeding of a high fat emulsion; 12 rats received a standard diet only and served as controls. Liver mechanics were measured ex vivo using shear wave velocity (SWV) induced by acoustic radiation force. The measured mean values of liver SWV ranged from 1.33 to 3.85m/s for different grades of steatosis. The area under the receiver operative characteristic curve (⩾S1) was equal to 0.82 (95% CI=0.69, 0.96) between the steatosis group and the normal group, and the optimal cutoff value was 2.59 with sensitivity of 88% and specificity of 76%. However, there are no significant differences in SWV measurements between the steatosis grades. SWV values did not correlate with the early grade of inflammation. In conclusion, ARFI elastography is a promising method for differentiating normal rat liver from rat liver with steatosis, but it cannot reliably predict the grade of steatosis in rat livers. The early grade of inflammation activity did not significantly affect the SWV measurements.

  17. Identifying Clinically Significant Prostate Cancers using 3-D In Vivo Acoustic Radiation Force Impulse Imaging with Whole-Mount Histology Validation.

    PubMed

    Palmeri, Mark L; Glass, Tyler J; Miller, Zachary A; Rosenzweig, Stephen J; Buck, Andrew; Polascik, Thomas J; Gupta, Rajan T; Brown, Alison F; Madden, John; Nightingale, Kathryn R

    2016-06-01

    Overly aggressive prostate cancer (PCa) treatment adversely affects patients and places an unnecessary burden on our health care system. The inability to identify and grade clinically significant PCa lesions is a factor contributing to excessively aggressive PCa treatment, such as radical prostatectomy, instead of more focal, prostate-sparing procedures such as cryotherapy and high-dose radiation therapy. We have performed 3-D in vivo B-mode and acoustic radiation force impulse (ARFI) imaging using a mechanically rotated, side-fire endorectal imaging array to identify regions suspicious for PCa in 29 patients being treated with radical prostatectomies for biopsy-confirmed PCa. Whole-mount histopathology analyses were performed to identify regions of clinically significant/insignificant PCa lesions, atrophy and benign prostatic hyperplasia. Regions of suspicion for PCa were reader-identified in ARFI images based on boundary delineation, contrast, texture and location. These regions of suspicion were compared with histopathology identified lesions using a nearest-neighbor regional localization approach. Of all clinically significant lesions identified on histopathology, 71.4% were also identified using ARFI imaging, including 79.3% of posterior and 33.3% of anterior lesions. Among the ARFI-identified lesions, 79.3% corresponded to clinically significant PCa lesions, with these lesions having higher indices of suspicion than clinically insignificant PCa. ARFI imaging had greater sensitivity for posterior versus anterior lesions because of greater displacement signal-to-noise ratio and finer spatial sampling. Atrophy and benign prostatic hyperplasia can cause appreciable prostate anatomy distortion and heterogeneity that confounds ARFI PCa lesion identification; however, in general, ARFI regions of suspicion did not coincide with these benign pathologies.

  18. Impulsive phase transport

    NASA Technical Reports Server (NTRS)

    Canfield, Richard C.; Bely-Dubau, Francoise; Brown, John C.; Dulk, George A.; Emslie, A. Gordon; Enome, Shinzo; Gabriel, Alan H.; Kundu, Mukul R.; Melrose, Donald; Neidig, Donald F.

    1986-01-01

    The transport of nonthermal electrons is explored. The thick-target electron beam model, in which electrons are presumed to be accelerated in the corona and typically thermalized primarily in the chromosphere and photosphere, is supported by observations throughout the electromagnetic spectrum. At the highest energies, the anisotropy of gamma-ray emission above 10 MeV clearly indicates that these photons are emitted by anisotropically-directed particles. The timing of this high-energy gamma-radiation with respect to lower-energy hard X-radiation implies that the energetic particles have short life-times. For collisional energy loss, this means that they are stopped in the chromosphere or below. Stereoscopic (two-spacecraft) observations at hard X-ray energies (up to 350 keV) imply that these lower-energy (but certainly nonthermal) electrons are also stopped deep in the chromosphere. Hard X-ray images show that, in spatially resolved flares whose radiation consists of impulsive bursts, the impulsive phase starts with X-radiation that comes mostly from the foot-points of coronal loops whose coronal component is outlined by microwaves.

  19. Simultaneous imaging and spectral observations in microwaves and hard X-rays of the impulsive phase of a solar limb flare

    NASA Technical Reports Server (NTRS)

    Schmahl, E. J.; Kundu, M. R.; Dennis, B. R.

    1986-01-01

    Observations of the impulsive phase of a solar flare at microwave wavelengths and in hard X-rays are used to deduce the strength of the magnetic field and the number of energetic electrons producing the burst. The microwave observations, using the VLA at 6 cm, had spatial resolution of 8 x 8 arcsec, close to the resolution of the Hard X-ray Imaging Spectrometer on SMM which also imaged this flare. The Hard X-ray Burst Spectrometer determined the spectrum of the burst in the range 25-512 keV, and several patrol telescopes recorded the microwave time profile at frequencies from 2.8 to 19.6 GHz. The combined data show that the derived number of microwave-emitting electrons is at least three orders of magnitude fewer than the number of thick target electrons producing the hard X-rays. It is proposed that the fast electrons are highly beamed and radiate gyrosynchrotron emission less efficiently than isotropically distributed electrons.

  20. Genetics of impulsive behaviour.

    PubMed

    Bevilacqua, Laura; Goldman, David

    2013-01-01

    Impulsivity, defined as the tendency to act without foresight, comprises a multitude of constructs and is associated with a variety of psychiatric disorders. Dissecting different aspects of impulsive behaviour and relating these to specific neurobiological circuits would improve our understanding of the etiology of complex behaviours for which impulsivity is key, and advance genetic studies in this behavioural domain. In this review, we will discuss the heritability of some impulsivity constructs and their possible use as endophenotypes (heritable, disease-associated intermediate phenotypes). Several functional genetic variants associated with impulsive behaviour have been identified by the candidate gene approach and re-sequencing, and whole genome strategies can be implemented for discovery of novel rare and common alleles influencing impulsivity. Via deep sequencing an uncommon HTR2B stop codon, common in one population, was discovered, with implications for understanding impulsive behaviour in both humans and rodents and for future gene discovery.

  1. Genetics of impulsive behaviour

    PubMed Central

    Bevilacqua, Laura; Goldman, David

    2013-01-01

    Impulsivity, defined as the tendency to act without foresight, comprises a multitude of constructs and is associated with a variety of psychiatric disorders. Dissecting different aspects of impulsive behaviour and relating these to specific neurobiological circuits would improve our understanding of the etiology of complex behaviours for which impulsivity is key, and advance genetic studies in this behavioural domain. In this review, we will discuss the heritability of some impulsivity constructs and their possible use as endophenotypes (heritable, disease-associated intermediate phenotypes). Several functional genetic variants associated with impulsive behaviour have been identified by the candidate gene approach and re-sequencing, and whole genome strategies can be implemented for discovery of novel rare and common alleles influencing impulsivity. Via deep sequencing an uncommon HTR2B stop codon, common in one population, was discovered, with implications for understanding impulsive behaviour in both humans and rodents and for future gene discovery. PMID:23440466

  2. Uniform and non-uniform modes of nanosecond-pulsed dielectric barrier discharge in atmospheric air: fast imaging and spectroscopic measurements of electric field

    PubMed Central

    Liu, Chong; Dobrynin, Danil; Fridman, Alexander

    2014-01-01

    In this study, we report experimental results on fast ICCD imaging of development of nanosecond-pulsed dielectric barrier discharge (DBD) in atmospheric air and spectroscopic measurements of electric field in the discharge. Uniformity of the discharge images obtained with nanosecond exposure times were analyzed using chi-square test. The results indicate that DBD uniformity strongly depends on applied (global) electric field in the discharge gap, and is a threshold phenomenon. We show that in the case of strong overvoltage on the discharge gap (provided by fast rise times), there is transition from filamentary to uniform DBD mode which correlates to the corresponding decrease of maximum local electric field in the discharge. PMID:25071294

  3. Virtual touch tissue imaging on acoustic radiation force impulse elastography: a new technique for differential diagnosis between benign and malignant thyroid nodules.

    PubMed

    Zhang, Yi-Feng; He, Yong; Xu, Hui-Xiong; Xu, Xiao-Hong; Liu, Chang; Guo, Le-Hang; Liu, Lin-Na; Xu, Jun-Mei

    2014-04-01

    Objectives- Acoustic radiation force impulse elastography is a newly developed ultrasound elasticity imaging technique that included both Virtual Touch tissue quantification and Virtual Touch tissue imaging (VTI; Siemens Medical Solutions, Mountain View, CA). This study aimed to evaluate the usefulness of VTI in differentiating malignant from benign thyroid nodules. Methods- This study included 192 consecutive patients with thyroid nodules (n = 219) who underwent surgery for compressive symptoms or suspicion of malignancy. Tissue stiffness on VTI elastography was scored from 1 (soft) to 6 (hard). The VTI scores between malignant and benign thyroid nodules were compared. The intraobserver and interobserver agreement for VTI elastography was also assessed. Results- On VTI elastography: score 1 was found in 84 nodules (all benign); score 2 in 37 nodules (3 papillary carcinomas and 34 benign nodules); score 3 in 25 nodules (1 medullary carcinoma, 6 papillary carcinomas, and 18 benign nodules); score 4 in 53 nodules (50 papillary carcinomas and 3 benign nodules); score 5 in 17 nodules (14 papillary carcinomas and 3 benign nodules); and score 6 in 3 nodules (all papillary carcinomas). A VTI elasticity score of 4 or greater was highly predictive of malignancy (P< .01), and the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were 87.0% (67 of 77), 95.8% (136 of 142), 91.8% (67 of 73), 93.1% (136 of 146), and 92.7% (203 of 219), respectively. The κ values were 0.69 for intraobserver agreement and 0.85 for interobserver agreement. Conclusions- Virtual Touch tissue elasticity imaging has great potential as an adjunctive tool combined with conventional sonography for differential diagnosis between benign and malignant thyroid nodules.

  4. Clinical application of Acoustic Radiation Force Impulse Imaging with Virtual Touch IQ in breast ultrasound: diagnostic performance and reproducibility of a new technique.

    PubMed

    Kapetas, Panagiotis; Pinker-Domenig, Katja; Woitek, Ramona; Clauser, Paola; Bernathova, Maria; Spick, Claudio; Helbich, Thomas; Baltzer, Pascal A

    2017-02-01

    Background Virtual Touch IQ (VTIQ) is a novel technique of quantitative sonoelastography that applies acoustic radiation force impulse (ARFI). Purpose To evaluate breast ARFI imaging with VTIQ in the clinical setting, with regard to reproducibility and diagnostic performance, and to specify cutoff limits for the differentiation of benign and malignant lesions. Material and Methods This retrospective study included 83 patients with 85 breast lesions (51 benign, 34 malignant) who received ARFI imaging with VTIQ. Two independent ARFI measurements of each lesion were performed and shear wave velocities (SWV) of the lesion and the adjacent tissues were measured. A lesion-to-fat velocity ratio (L/F Ratio) was calculated for each lesion. Diagnostic performance of SWV measurements and L/F Ratios was evaluated with receiver operating curve (ROC) analysis. The intraclass correlation coefficient and Bland-Altman plots were used to evaluate measurement reproducibility. Results All measurements showed equal diagnostic performance, as measured by the area under the ROC curve (0.853 for SWV, 0.882 for the L/F Ratio). At a cutoff value of 3.23 m/s, sensitivity and specificity were 82.4% and 80.4%, respectively. An L/F Ratio cutoff value of 2.23 revealed a sensitivity and specificity of 89.7% and 76.5%. The reproducibility of the SWV measurements was moderate (limits of agreement, 40.3-44.4%) and higher than that of the L/F Ratios (54.5-60.2%). Conclusion ARFI imaging with VTIQ is a novel, moderately reproducible, quantitative elastography technique, which provides useful information for the differentiation of benign and malignant breast lesions in the clinical setting.

  5. Obstacle avoidance and concealed target detection using the Army Research Lab ultra-wideband synchronous impulse reconstruction (UWB SIRE) forward imaging radar

    NASA Astrophysics Data System (ADS)

    Nguyen, Lam; Wong, David; Ressler, Marc; Koenig, Francois; Stanton, Brian; Smith, Gregory; Sichina, Jeffrey; Kappra, Karl

    2007-04-01

    The U.S. Army Research Laboratory (ARL), as part of a mission and customer funded exploratory program, has developed a new low-frequency, ultra-wideband (UWB) synthetic aperture radar (SAR) for forward imaging to support the Army's vision of an autonomous navigation system for robotic ground vehicles. These unmanned vehicles, equipped with an array of imaging sensors, will be tasked to help detect man-made obstacles such as concealed targets, enemy minefields, and booby traps, as well as other natural obstacles such as ditches, and bodies of water. The ability of UWB radar technology to help detect concealed objects has been documented in the past and could provide an important obstacle avoidance capability for autonomous navigation systems, which would improve the speed and maneuverability of these vehicles and consequently increase the survivability of the U. S. forces on the battlefield. One of the primary features of the radar is the ability to collect and process data at combat pace in an affordable, compact, and lightweight package. To achieve this, the radar is based on the synchronous impulse reconstruction (SIRE) technique where several relatively slow and inexpensive analog-to-digital (A/D) converters are used to sample the wide bandwidth of the radar signals. We conducted an experiment this winter at Aberdeen Proving Ground (APG) to support the phenomenological studies of the backscatter from positive and negative obstacles for autonomous robotic vehicle navigation, as well as the detection of concealed targets of interest to the Army. In this paper, we briefly describe the UWB SIRE radar and the test setup in the experiment. We will also describe the signal processing and the forward imaging techniques used in the experiment. Finally, we will present imagery of man-made obstacles such as barriers, concertina wires, and mines.

  6. Fast calcium and voltage-sensitive dye imaging in enteric neurones reveal calcium peaks associated with single action potential discharge.

    PubMed

    Michel, K; Michaelis, M; Mazzuoli, G; Mueller, K; Vanden Berghe, P; Schemann, M

    2011-12-15

    Slow changes in [Ca(2+)](i) reflect increased neuronal activity. Our study demonstrates that single-trial fast [Ca(2+)](i) imaging (≥200 Hz sampling rate) revealed peaks each of which are associated with single spike discharge recorded by consecutive voltage-sensitive dye (VSD) imaging in enteric neurones and nerve fibres. Fast [Ca(2+)](i) imaging also revealed subthreshold fast excitatory postsynaptic potentials. Nicotine-evoked [Ca(2+)](i) peaks were reduced by -conotoxin and blocked by ruthenium red or tetrodotoxin. Fast [Ca(2+)](i) imaging can be used to directly record single action potentials in enteric neurones. [Ca(2+)](i) peaks required opening of voltage-gated sodium and calcium channels as well as Ca(2+) release from intracellular stores.

  7. Impulsive action: emotional impulses and their control

    PubMed Central

    Frijda, Nico H.; Ridderinkhof, K. Richard; Rietveld, Erik

    2014-01-01

    This paper presents a novel theoretical view on impulsive action, integrating thus far separate perspectives on non-reflective action, motivation, emotion regulation, and impulse control. We frame impulsive action in terms of directedness of the individual organism toward, away, or against other givens – toward future states and away from one’s present state. First, appraisal of a perceived or thought-of event or object on occasion, rapidly and without premonition or conscious deliberation, triggers a motive to modify one’s relation to that event or object. Situational specifics of the event as perceived and appraised motivate and guide selection of readiness for a particular kind of purposive action. Second, perception of complex situations can give rise to multiple appraisals, multiple motives, and multiple simultaneous changes in action readiness. Multiple states of action readiness may interact in generating action, by reinforcing or attenuating each other, thereby yielding impulse control. We show how emotion control can itself result from a motive state or state of action readiness. Our view links impulsive action mechanistically to states of action readiness, which is the central feature of what distinguishes one kind of emotion from another. It thus provides a novel theoretical perspective to the somewhat fragmented literature on impulsive action. PMID:24917835

  8. Particle image velocimetry analysis of the flow around circular cylinder induced by arc discharge rotating in magnetic field

    NASA Astrophysics Data System (ADS)

    Munhoz, D. S.; Bityurin, V. A.; Klimov, A. I.; Moralev, I. A.

    2016-11-01

    An experimental study of the flow around a circular cylinder model with magnetohydrodynamic (MHD) actuator was carried out in subsonic wind tunnels (M < 0.2). Combined (high frequency and pulsed-periodic) electrical discharge was used in this MHD actuator. This intense pulsed-periodic discharge had the following characteristics: voltage amplitude up to 15 kV, current amplitude up to 16 A and frequency up to 1 kHz. Permanent magnets with an induction of B = 0.1 T on the model surface were placed inside the cylindrical model. Annular electrodes were situated on the surface of the cylindrical model. The Lorentz force causes the rotation of the electric arc on the model surface. In turn, the movement of the arc discharge induces the rotation of the gas near the surface of the model. In this experiment were carried out the measurement of the flow velocity profile near the surface of the model on the following operational modes: with plasma and without plasma. A parametric study of the aerodynamic performance of the model was fulfilled with respect to the discharge parameters and the flow velocity. To measure the velocity profile was used particle image velocimetry method.

  9. Non-Destructive Monitoring of Charge-Discharge Cycles on Lithium Ion Batteries using 7Li Stray-Field Imaging

    PubMed Central

    Tang, Joel A.; Dugar, Sneha; Zhong, Guiming; Dalal, Naresh S.; Zheng, Jim P.; Yang, Yong; Fu, Riqiang

    2013-01-01

    Magnetic resonance imaging provides a noninvasive method for in situ monitoring of electrochemical processes involved in charge/discharge cycling of batteries. Determining how the electrochemical processes become irreversible, ultimately resulting in degraded battery performance, will aid in developing new battery materials and designing better batteries. Here we introduce the use of an alternative in situ diagnostic tool to monitor the electrochemical processes. Utilizing a very large field-gradient in the fringe field of a magnet, stray-field-imaging (STRAFI) technique significantly improves the image resolution. These STRAFI images enable the real time monitoring of the electrodes at a micron level. It is demonstrated by two prototype half-cells, graphite∥Li and LiFePO4∥Li, that the high-resolution 7Li STRAFI profiles allow one to visualize in situ Li-ions transfer between the electrodes during charge/discharge cyclings as well as the formation and changes of irreversible microstructures of the Li components, and particularly reveal a non-uniform Li-ion distribution in the graphite. PMID:24005580

  10. Evaluating the Feasibility of Acoustic Radiation Force Impulse Shear Wave Elasticity Imaging of the Uterine Cervix With an Intracavity Array: A Simulation Study

    PubMed Central

    Feltovich, Helen; Homyk, Andrew D.; Carlson, Lindsey C.; Hall, Timothy J.

    2015-01-01

    The uterine cervix softens, shortens, and dilates throughout pregnancy in response to progressive disorganization of its layered collagen microstructure. This process is an essential part of normal pregnancy, but premature changes are associated with preterm birth. Clinically, there are no reliable noninvasive methods to objectively measure cervical softening or assess cervical microstructure. The goal of these preliminary studies was to evaluate the feasibility of using an intracavity ultrasound array to generate acoustic radiation force impulse (ARFI) excitations in the uterine cervix through simulation, and to optimize the acoustic radiation force (ARF) excitation for shear wave elasticity imaging (SWEI) of the tissue stiffness. The cervix is a unique soft tissue target for SWEI because it has significantly greater acoustic attenuation (α = 1.3 to 2.0 dB·cm−1·MHz−1) than other soft tissues, and the pathology being studied tends to lead to an increase in tissue compliance, with healthy cervix being relatively stiff compared with other soft tissues (E ≈ 25 kPa). Additionally, the cervix can only be accessed in vivo using a transvaginal or catheter-based array, which places additional constraints on the excitation focal characteristics that can be used during SWEI. Finite element method (FEM) models of SWEI show that larger-aperture, catheter-based arrays can utilize excitation frequencies up to 7 MHz to generate adequate focal gain up to focal depths 10 to 15 mm deep, with higher frequencies suffering from excessive amounts of near-field acoustic attenuation. Using full-aperture excitations can yield ~40% increases in ARFI-induced displacements, but also restricts the depth of field of the excitation to ~0.5 mm, compared with 2 to 6 mm, which limits the range that can be used for shear wave characterization of the tissue. The center-frequency content of the shear wave particle velocity profiles ranges from 1.5 to 2.5 kHz, depending on the focal

  11. Barratt Impulsivity and Neural Regulation of Physiological Arousal

    PubMed Central

    Zhang, Sheng; Hu, Sien; Hu, Jianping; Wu, Po-Lun; Chao, Herta H.; Li, Chiang-shan R.

    2015-01-01

    Background Theories of personality have posited an increased arousal response to external stimulation in impulsive individuals. However, there is a dearth of studies addressing the neural basis of this association. Methods We recorded skin conductance in 26 individuals who were assessed with Barratt Impulsivity Scale (BIS-11) and performed a stop signal task during functional magnetic resonance imaging. Imaging data were processed and modeled with Statistical Parametric Mapping. We used linear regressions to examine correlations between impulsivity and skin conductance response (SCR) to salient events, identify the neural substrates of arousal regulation, and examine the relationship between the regulatory mechanism and impulsivity. Results Across subjects, higher impulsivity is associated with greater SCR to stop trials. Activity of the ventromedial prefrontal cortex (vmPFC) negatively correlated to and Granger caused skin conductance time course. Furthermore, higher impulsivity is associated with a lesser strength of Granger causality of vmPFC activity on skin conductance, consistent with diminished control of physiological arousal to external stimulation. When men (n = 14) and women (n = 12) were examined separately, however, there was evidence suggesting association between impulsivity and vmPFC regulation of arousal only in women. Conclusions Together, these findings confirmed the link between Barratt impulsivity and heightened arousal to salient stimuli in both genders and suggested the neural bases of altered regulation of arousal in impulsive women. More research is needed to explore the neural processes of arousal regulation in impulsive individuals and in clinical conditions that implicate poor impulse control. PMID:26079873

  12. Acoustic Radiation Force Impulse Imaging for the Differentiation of Benign and Malignant Lymph Nodes: A Systematic Review and Meta-Analysis

    PubMed Central

    Yu, Cheng; Xie, Mingxing; Lv, Qing

    2016-01-01

    Objective To evaluate the overall performance of acoustic radiation force impulse imaging (ARFI) in differentiating between benign and malignant lymph nodes (LNs) by conducting a meta-analysis. Methods PubMed, Embase, Web of Science, the Cochrane Library and the China National Knowledge Infrastructure were comprehensively searched for potential studies through August 13th, 2016. Studies that investigated the diagnostic power of ARFI for the differential diagnosis of benign and malignant LNs by using virtual touch tissue quantification (VTQ) or virtual touch tissue imaging quantification (VTIQ) were collected. The included articles were published in English or Chinese. Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) was used to evaluate the methodological quality. The pooled sensitivity, specificity, and the area under the summary receiver operating characteristic (SROC) curve (AUC) were calculated by means of a bivariate mixed-effects regression model. Meta-regression analysis was performed to identify the potential sources of between study heterogeneity. Fagan plot analysis was used to explore the clinical utilities. Publication bias was assessed using Deek’s funnel plot. Results Nine studies involving 1084 LNs from 929 patients were identified to analyze in the meta-analysis. The summary sensitivity and specificity of ARFI in detecting malignant LNs were 0.87 (95% confidence interval [CI], 0.83–0.91) and 0.88 (95% CI, 0.82–0.92), respectively. The AUC was 0.93 (95% CI, 0.90–0.95). The pooled DOR was 49.59 (95% CI, 26.11–94.15). Deek’s funnel plot revealed no significant publication bias. Conclusion ARFI is a promising tool for the differentiation of benign and malignant LNs with high sensitivity and specificity. PMID:27855188

  13. Nerve Impulses in Plants

    ERIC Educational Resources Information Center

    Blatt, F. J.

    1974-01-01

    Summarizes research done on the resting and action potential of nerve impulses, electrical excitation of nerve cells, electrical properties of Nitella, and temperature effects on action potential. (GS)

  14. Sensing through the wall imaging using the Army Research Lab ultra-wideband synchronous impulse reconstruction (UWB SIRE) radar

    NASA Astrophysics Data System (ADS)

    Nguyen, Lam; Ressler, Marc; Sichina, Jeffrey

    2008-04-01

    The U.S. Army Research Laboratory (ARL), as part of a mission and customer funded exploratory program, has developed a new low-frequency, ultra-wideband (UWB) synthetic aperture radar (SAR). The radar is capable of penetrating enclosed areas (buildings) and generating SAR imagery. This supports the U.S. Army's need for intelligence on the configuration, content, and human presence inside these enclosed areas. The radar system is mounted on a ground based vehicle traveling along the road and is configured with an array of antennas pointing toward the enclosed areas of interest. This paper will describe an experiment conducted recently at Aberdeen Proving Ground (APG), Maryland. In this paper we briefly describe the UWB SIRE radar and the test setup in the experiment. We will also describe the signal processing and the image techniques used to produce the SAR imagery. Finally, we will present SAR imagery of the building and its internal structure from different viewing directions.

  15. Diagnostics of Rotational Temperature and Mean Electron Energy Distribution of DC Glow Discharge Using Spectral Image Processing

    NASA Astrophysics Data System (ADS)

    Shimizu, Daisuke; Sasamoto, Ryo; Matsumoto, Takao; Izawa, Yasuji; Nishijima, Kiyoto

    2014-10-01

    The non-thermal plasma has been used in various application fields of manufacturing industry such as surface reforming, plasma etching, deposited film forming. The gas temperature and electron energy in non-thermal plasma play a key role of production of active species. Therefore, it is essential to understand the properties of non-thermal plasma for effective plasma applications. In this study, the two-dimensional rotational temperature and mean electron energy distribution of DC glow discharge plasma under various air pressures were observed using spectral image processing. Rotational temperature distribution was estimated from the emission intensity ratio of head and tail of 2nd positive system band of N2 (0, 2). On the other hand, mean electron energy was estimated from the emission intensity ratio of 2nd positive system band of N2 (0, 2) and 1st negative system band of N2+ (0, 0). The each spectral images were taken by an ICCD camera with narrow band-path filters respectively. As a result, the dependences of rotational temperature and mean electron energy distribution in DC glow discharge on ambient air pressure were clearly observed using spectral image processing.

  16. A Neurogenetic Approach to Impulsivity

    PubMed Central

    Congdon, Eliza; Canli, Turhan

    2008-01-01

    Impulsivity is a complex and multidimensional trait that is of interest to both personality psychologists and to clinicians. For investigators seeking the biological basis of personality traits, the use of neuroimaging techniques such as positron emission tomography (PET) and functional magnetic resonance imaging (fMRI) revolutionized personality psychology in less than a decade. Now, another revolution is under way, and it originates from molecular biology. Specifically, new findings in molecular genetics, the detailed mapping and the study of the function of genes, have shown that individual differences in personality traits can be related to individual differences within specific genes. In this article, we will review the current state of the field with respect to the neural and genetic basis of trait impulsivity. PMID:19012655

  17. Impulsivity and Academic Cheating

    ERIC Educational Resources Information Center

    Anderman, Eric M.; Cupp, Pamela K.; Lane, Derek

    2009-01-01

    The authors examined the relations between academic cheating and impulsivity in a large sample of adolescents enrolled in high school health education classes. Results indicated that impulsivity predicts academic cheating for students who report extensive involvement in cheating. However, students who engage in extensive cheating are less likely…

  18. Rethinking Impulsivity in Suicide

    ERIC Educational Resources Information Center

    Klonsky, E. David; May, Alexis

    2010-01-01

    Elevated impulsivity is thought to facilitate the transition from suicidal thoughts to suicidal behavior. Therefore, impulsivity should distinguish those who have attempted suicide (attempters) from those who have only considered suicide (ideators-only). This hypothesis was examined in three large nonclinical samples: (1) 2,011 military recruits,…

  19. Time-resolved imaging of electrical discharge development in underwater bubbles

    SciTech Connect

    Tu, Yalong; Xia, Hualei; Yang, Yong E-mail: luxinpei@hust.edu.cn; Lu, Xinpei E-mail: luxinpei@hust.edu.cn

    2016-01-15

    The formation and development of plasma in single air bubbles submerged in water were investigated. The difference in the discharge dynamics and the after-effects on the bubble were investigated using a 900 000 frame per second high-speed charge-coupled device camera. It was observed that depending on the position of the electrodes, the breakdown could be categorized into two modes: (1) direct discharge mode, where the high voltage and ground electrodes were in contact with the bubble, and the streamer would follow the shortest path and propagate along the axis of the bubble and (2) dielectric barrier mode, where the ground electrode was not in touch with the bubble surface, and the streamer would form along the inner surface of the bubble. The oscillation of the bubble and the development of instabilities on the bubble surface were also discussed.

  20. [¹¹C]-(+)-PHNO PET imaging of dopamine D(2/3) receptors in Parkinson's disease with impulse control disorders.

    PubMed

    Payer, Doris E; Guttman, Mark; Kish, Stephen J; Tong, Junchao; Strafella, Antonio; Zack, Martin; Adams, John R; Rusjan, Pablo; Houle, Sylvain; Furukawa, Yoshiaki; Wilson, Alan A; Boileau, Isabelle

    2015-02-01

    Dopamine agonist medications with high affinity for the D3 dopamine receptor are commonly used to treat Parkinson's disease, and have been associated with pathological behaviors categorized under the umbrella of impulse control disorders (ICD). The aim of this study was to investigate whether ICD in Parkinson's patients are associated with greater D3 dopamine receptor availability. We used positron emission tomography (PET) radioligand imaging with the D3 dopamine receptor preferring agonist [¹¹C]-(+)-propyl-hexahydro-naphtho-oxazin (PHNO) in Parkinson's patients with (n = 11) and without (n = 21) ICD, and age-, sex-, and education-matched healthy control subjects (n = 18). Contrary to hypotheses, [¹¹C]-(+)-PHNO binding in D3 -rich brain areas was not elevated in Parkinson's patients with ICD compared with those without; instead, [¹¹C]-(+)-PHNO binding in ventral striatum was 20% lower (P = 0.011), correlating with two measures of ICD severity (r = -0.8 and -0.9), which may reflect higher dopamine tone in ventral striatum. In dorsal striatum, where [¹¹C]-(+)-PHNO binding is associated with D2 receptor levels, [¹¹C]-(+)-PHNO binding was elevated across patients compared with controls. We conclude that although D3 dopamine receptors have been linked to the occurrence of ICD in Parkinson's patients. Our findings do not support the hypothesis that D3 receptor levels are elevated in Parkinson's patients with ICD. We also did not find ICD-related abnormalities in D2 receptor levels. Our findings argue against the possibility that differences in D2/3 receptor levels can account for the development of ICD in PD; however, we cannot rule out that differences in dopamine levels (particularly in ventral striatum) may be involved.

  1. Evaluation of Transient Elastography, Acoustic Radiation Force Impulse Imaging (ARFI), and Enhanced Liver Function (ELF) Score for Detection of Fibrosis in Morbidly Obese Patients

    PubMed Central

    Karlas, Thomas; Dietrich, Arne; Peter, Veronica; Wittekind, Christian; Lichtinghagen, Ralf; Garnov, Nikita; Linder, Nicolas; Schaudinn, Alexander; Busse, Harald; Prettin, Christiane; Keim, Volker; Tröltzsch, Michael; Schütz, Tatjana; Wiegand, Johannes

    2015-01-01

    Background Liver fibrosis induced by non-alcoholic fatty liver disease causes peri-interventional complications in morbidly obese patients. We determined the performance of transient elastography (TE), acoustic radiation force impulse (ARFI) imaging, and enhanced liver fibrosis (ELF) score for fibrosis detection in bariatric patients. Patients and Methods 41 patients (median BMI 47 kg/m2) underwent 14-day low-energy diets to improve conditions prior to bariatric surgery (day 0). TE (M and XL probe), ARFI, and ELF score were performed on days -15 and -1 and compared with intraoperative liver biopsies (NAS staging). Results Valid TE and ARFI results at day -15 and -1 were obtained in 49%/88% and 51%/90% of cases, respectively. High skin-to-liver-capsule distances correlated with invalid TE measurements. Fibrosis of liver biopsies was staged as F1 and F3 in n = 40 and n = 1 individuals. However, variations (median/range at d-15/-1) of TE (4.6/2.6–75 and 6.7/2.9–21.3 kPa) and ARFI (2.1/0.7–3.7 and 2.0/0.7–3.8 m/s) were high and associated with overestimation of fibrosis. The ELF score correctly classified 87.5% of patients. Conclusion In bariatric patients, performance of TE and ARFI was poor and did not improve after weight loss. The ELF score correctly classified the majority of cases and should be further evaluated. PMID:26528818

  2. RAPID EVOLUTION OF THE SOLAR ATMOSPHERE DURING THE IMPULSIVE PHASE OF A MICROFLARE OBSERVED WITH THE EXTREME-ULTRAVIOLET IMAGING SPECTROMETER ABOARD HINODE: HINTS OF CHROMOSPHERIC MAGNETIC RECONNECTION

    SciTech Connect

    Brosius, Jeffrey W.

    2013-11-10

    We obtained rapid cadence (11.2 s) EUV stare spectra of a solar microflare with the Extreme-ultraviolet Imaging Spectrometer aboard Hinode. The intensities of lines formed at temperatures too cool to be found in the corona brightened by factors around 16 early during this event, indicating that we observed a site of energy deposition in the chromosphere. We derive the density evolution of the flare plasma at temperature around 2 MK from the intensity ratio of Fe XIV lines at 264.789 Å and 274.204 Å. From both lines we removed the bright pre-flare quiescent emission, and from 274.204 we removed the blended emission of Si VII λ274.180 based on the Si VII λ274.180/275.361 intensity ratio, which varies only slightly with density. In this way the flare electron density is derived with emission from only the flare plasma. The density increased by an order of magnitude from its pre-flare quiescent average of (3.43 ± 0.19) × 10{sup 9} cm{sup –3} to its maximum impulsive phase value of (3.04 ± 0.57) × 10{sup 10} cm{sup –3} in 2 minutes. The fact that this rapid increase in density is not accompanied by systematic, large upward velocities indicates that the density increase is not due to the filling of loops with evaporated chromospheric material, but rather due to material being directly heated in the chromosphere, likely by magnetic reconnection. The density increase may be due to a progression of reconnection sites to greater depths in the chromosphere, where it has access to larger densities, or it may be due to compression of 2 MK plasma by the 10 MK plasma as it attempts to expand against the high-density chromospheric plasma.

  3. Ion energies in high power impulse magnetron sputtering with and without localized ionization zones

    SciTech Connect

    Yang, Yuchen; Tanaka, Koichi; Liu, Jason; Anders, André

    2015-03-23

    High speed imaging of high power impulse magnetron sputtering discharges has revealed that ionization is localized in moving ionization zones but localization disappears at high currents for high yield targets. This offers an opportunity to study the effect ionization zones have on ion energies. We measure that ions have generally higher energies when ionization zones are present, supporting the concept that these zones are associated with moving potential humps. We propose that the disappearance of ionization zones is caused by an increased supply of atoms from the target which cools electrons and reduces depletion of atoms to be ionized.

  4. Spine surgery - discharge

    MedlinePlus

    ... symptoms should get better in a few weeks. Recovery after laminectomy and fusion surgery is longer. You will not be able ... discharge; Anterior spinal fusion - discharge; Spine surgery - spinal fusion - discharge Images Spinal surgery -- cervical - series References Agrawal BM, Zeidman SM, Rhines L, ...

  5. Gallbladder removal - laparoscopic - discharge

    MedlinePlus

    Cholecystectomy laparoscopic - discharge; Cholelithiasis - laparoscopic discharge; Biliary calculus - laparoscopic discharge; Gallstones - laparoscopic discharge; Cholecystitis - laparoscopic discharge

  6. Imaging and spatio-temporal analysis of turbulent mixing of hydrothermal water discharging into a river (Breitenbush Hot Springs, Oregon)

    NASA Astrophysics Data System (ADS)

    Andrews, B. J.; Cardenas, M. B.; Bennett, P.

    2009-12-01

    High-frequency (16 Hz), high-resolution (1-2 mm pixels) thermal infrared images show the effects of jet entry conditions on spatial and temporal scales of mixing between a discharging plume of hot spring water (~60 °C) and a small stream (~10 °C) at Breitenbush Hot Springs, Oregon. Images of thermal plumes showing eddy cascades through space and time are analyzed with correlation analyses to obtain timescales and length-scales of mixing. Optical flow velocimetry of the images provides insight to the transient two-dimensional flow fields of the plumes. The 3-inch diameter discharge pipe was positioned such that the jet is at the surface, partially submerged, or at the bottom of the 15-cm deep stream. The three jet entry conditions are hereafter referred to as “shallow”, “middle”, and “deep”. In the shallow and middle positions, the jet is apparent on the stream surface as a hot region extending downstream from the pipe. Turbulent mixing between the jet and the stream occurs along the jet margins, such that the discharge plume broadens and cools downstream. In the deep position, the jet reaches the surface as a broad plume ~7.5 cm downstream from the pipe; the highest measured temperatures are not directly above the pipe mouth, but displaced downstream. Streamwise spatial autocorrelation analysis of the temperature field under shallow and middle entry conditions show correlation length scales of ~30 cm for a transect along the center ~7.5 cm of the jet; the correlation length scale abruptly reduces to <10 cm on either side of the jet. Under deep conditions, the streamwise correlation length scale is ~20 cm along the middle ~10 cm of the plume and ~10 cm on either side of the plume. Temporal autocorrelation analysis of the temperature fields shows quasi-periodicity for all three pipe positions and decrease in frequency with distance from the pipe (shallow and middle) or center of the upwelling plume (deep). Correlation analyses of the velocity fields

  7. Fractionating impulsivity: neuropsychiatric implications.

    PubMed

    Dalley, Jeffrey W; Robbins, Trevor W

    2017-02-17

    The ability to make decisions and act quickly without hesitation can be advantageous in many settings. However, when persistently expressed, impulsive decisions and actions are considered risky, maladaptive and symptomatic of such diverse brain disorders as attention-deficit hyperactivity disorder, drug addiction and affective disorders. Over the past decade, rapid progress has been made in the identification of discrete neural networks that underlie different forms of impulsivity - from impaired response inhibition and risky decision making to a profound intolerance of delayed rewards. Herein, we review what is currently known about the neural and psychological mechanisms of impulsivity, and discuss the relevance and application of these new insights to various neuropsychiatric disorders.

  8. Pancreatitis - discharge

    MedlinePlus

    Chronic pancreatitis - discharge; Pancreatitis - chronic - discharge; Pancreatic insufficiency - discharge; Acute pancreatitis - discharge ... fluids through an intravenous (IV) tube in your vein and nutrition through a feeding tube or IV. ...

  9. Draft tube discharge fluctuation during self-sustained pressure surge: fluorescent particle image velocimetry in two-phase flow

    NASA Astrophysics Data System (ADS)

    Müller, A.; Dreyer, M.; Andreini, N.; Avellan, F.

    2013-04-01

    Hydraulic machines play an increasingly important role in providing a secondary energy reserve for the integration of renewable energy sources in the existing power grid. This requires a significant extension of their usual operating range, involving the presence of cavitating flow regimes in the draft tube. At overload conditions, the self-sustained oscillation of a large cavity at the runner outlet, called vortex rope, generates violent periodic pressure pulsations. In an effort to better understand the nature of this unstable behavior and its interaction with the surrounding hydraulic and mechanical system, the flow leaving the runner is investigated by means of particle image velocimetry. The measurements are performed in the draft tube cone of a reduced scale model of a Francis turbine. A cost-effective method for the in-house production of fluorescent seeding material is developed and described, based on off-the-shelf polyamide particles and Rhodamine B dye. Velocity profiles are obtained at three streamwise positions in the draft tube cone, and the corresponding discharge variation in presence of the vortex rope is calculated. The results suggest that 5-10 % of the discharge in the draft tube cone is passing inside the vortex rope.

  10. A novel technique to monitor thermal discharges using thermal infrared imaging.

    PubMed

    Muthulakshmi, A L; Natesan, Usha; Ferrer, Vincent A; Deepthi, K; Venugopalan, V P; Narasimhan, S V

    2013-09-01

    Coastal temperature is an important indicator of water quality, particularly in regions where delicate ecosystems sensitive to water temperature are present. Remote sensing methods are highly reliable for assessing the thermal dispersion. The plume dispersion from the thermal outfall of the nuclear power plant at Kalpakkam, on the southeast coast of India, was investigated from March to December 2011 using thermal infrared images along with field measurements. The absolute temperature as provided by the thermal infrared (TIR) images is used in the Arc GIS environment for generating a spatial pattern of the plume movement. Good correlation of the temperature measured by the TIR camera with the field data (r(2) = 0.89) make it a reliable method for the thermal monitoring of the power plant effluents. The study portrays that the remote sensing technique provides an effective means of monitoring the thermal distribution pattern in coastal waters.

  11. Full-Scale Schlieren Imaging of Firearms Discharge and Bullets in Flight

    NASA Astrophysics Data System (ADS)

    Grumstrup, Torben; Settles, Gary; Dodson-Dreibelbis, Lori

    2003-11-01

    A lens-and-grid-type schlieren system using a very large grid as a light source, thus having a 2x3m field-of-view, was described at previous APS/DFD meetings. The implementation of high-speed still imaging and cinematography of shock waves with this system has also been described. Schlieren methods and external ballistics have been closely related since Mach and Salcher first photographed shock waves about a bullet in 1887. The reason to revisit the topic here is that a large field of view allows imaging not only of the bullet and muzzle blast, but also of shock wave interactions with the surroundings and with the person firing the gun. Microsecond still images reveal various stages of these phenomena for both transonic and supersonic (pistol and rifle) bullets. High-speed movies at 30,000 frames/s are also presented. Some implications of these results for hearing protection while using firearms, the improvement of gun and ammunition design and safety, and forensic investigations of close-range bullet wounds are discussed.

  12. Neural substrates of time perception and impulsivity.

    PubMed

    Wittmann, Marc; Simmons, Alan N; Flagan, Taru; Lane, Scott D; Wackermann, Jiří; Paulus, Martin P

    2011-08-11

    Several studies provide empirical evidence for the association between impulsivity and time perception. However, little is known about the neural substrates underlying this function. This investigation examined the influence of impulsivity on neural activation patterns during the encoding and reproduction of intervals with durations of 3, 9 and 18s using event-related functional magnetic resonance imaging (fMRI). Twenty-seven subjects participated in this study, including 15 high impulsive subjects that were classified based on their self-rating. FMRI activation during the duration reproduction task was correlated with measures of two self-report questionnaires related to the concept of impulsivity (Barratt Impulsiveness Scale, BIS; Zimbardo Time Perspective Inventory, ZTPI). Behaviorally, those individuals who under-reproduced temporal intervals also showed lower scores on the ZTPI future perspective subscale and higher scores on the BIS. FMRI activation revealed an accumulating pattern of neural activity peaking at the end of the 9- and 18-s intervals within right posterior insula. Activations of brain regions during the reproduction phase of the timing task, such as those related to motor execution as well as to the 'core control network' - encompassing the inferior frontal and medial frontal cortices, the anterior insula as well as the inferior parietal cortex - were significantly correlated with reproduced duration, as well as with BIS and ZTPI subscales. In particular, the greater activation in these regions the shorter were the reproduced intervals, the more impulsive was an individual and the less pronounced the future perspective. Activation in the core control network, thus, may form a biological marker for cognitive time management and for impulsiveness.

  13. Neural substrates of time perception and impulsivity

    PubMed Central

    Wittmann, Marc; Simmons, Alan N.; Flagan, Taru; Lane, Scott D.; Wackermann, Jiří; Paulus, Martin P.

    2011-01-01

    Several studies provide empirical evidence for the association between impulsivity and time perception. However, little is known about the neural substrates underlying this function. This investigation examined the influence of impulsivity on neural activation patterns during the encoding and reproduction of intervals with durations of 3, 9 and 18 seconds using event-related functional magnetic resonance imaging (fMRI). Twenty-seven subjects participated in this study, including 15 high impulsive subjects that were classified based on their self-rating. FMRI activation during the duration reproduction task was correlated with measures of two self-report questionnaires related to the concept of impulsivity (Barratt Impulsiveness Scale, BIS; Zimbardo Time Perspective Inventory, ZTPI). Behaviorally, those individuals who under-reproduced temporal intervals also showed lower scores on the ZTPI future perspective subscale and higher scores on the BIS. FMRI activation revealed an accumulating pattern of neural activity peaking at the end of the 9- and 18-s interval within right posterior insula. Activations of brain regions during the reproduction phase of the timing task, such as those related to motor execution as well as to the ‘core control network’ – encompassing the inferior frontal and medial frontal cortex, the anterior insula as well as the inferior parietal cortex – were significantly correlated with reproduced duration, as well as with BIS and ZTPI subscales. In particular, the greater activation in these regions the shorter were the reproduced intervals, the more impulsive was an individual and the less pronounced the future perspective. Activation in the core control network, thus, may form a biological marker for cognitive time management and for impulsiveness. PMID:21763642

  14. Ballistic impulse gauge

    DOEpatents

    Ault, Stanley K.

    1993-01-01

    A gauge for detecting the impulse generated in sample materials by X-rays or other impulse producing mechanisms utilizes a pair of flat annular springs to support a plunger relative to a housing which may itself be supported by a pair of flat annular springs in a second housing. The plunger has a mounting plate mounted on one end and at the other, a position or velocity transducer is mounted. The annular springs consist of an outer ring and an inner ring with at least three arcuate members connecting the outer ring with the inner ring.

  15. Ballistic impulse gauge

    DOEpatents

    Ault, S.K.

    1993-12-21

    A gauge for detecting the impulse generated in sample materials by X-rays or other impulse producing mechanisms utilizes a pair of flat annular springs to support a plunger relative to a housing which may itself be supported by a pair of flat annular springs in a second housing. The plunger has a mounting plate mounted on one end and at the other, a position or velocity transducer is mounted. The annular springs consist of an outer ring and an inner ring with at least three arcuate members connecting the outer ring with the inner ring. 4 figures.

  16. Imaging diagnostics of pulsed plasma discharges in saline generated with various sharp pin powered electrodes

    NASA Astrophysics Data System (ADS)

    Asimakoulas, L.; Karim, M. L.; Dostal, L.; Krcma, F.; Graham, W. G.; Field, T. A.

    2016-09-01

    Plasmas formed by 1 ms pulses of between 180 and 300 V applied to sharp pin-like electrodes immersed in saline solution have been imaged with a Photron SA-X2 fast framing camera and an Andor iStar 510 ICCD camera. Stainless steel, Tungsten and Gold electrodes were investigated with tip diameters of 30 μm, 1 μm and < 1 μ m respectively. As previously observed, a vapour layer forms around the electrode prior to plasma ignition. For gold and stainless steel lower voltages were required to minimize electrode damage. Preliminary anlaysis indicates at lower voltages for all tips the fast framing results show that light emission is normally centred on a single small volume, which appears to move about, but remains close to the tip. In the case of Tungsten with higher voltages or longer pulses the tip of the needle can heat up to incandescent temperatures. At higher voltages shock wave fronts appear to be observed as the vapour layer collapses at the end of the voltage pulse. Backlighting and no lighting to observe bubble/vapour layer formation and emission due to plasma formation were employed. Sometimes at higher voltages a thicker vapour layer engulfs the tip and no plasma emission/current is observed.

  17. Lung surgery - discharge

    MedlinePlus

    Thoracotomy - discharge; Lung tissue removal - discharge; Pneumonectomy - discharge; Lobectomy - discharge; Lung biopsy - discharge; Thoracoscopy - discharge; Video-assisted thoracoscopic surgery - discharge; VATS - ...

  18. Relativistic impulse dynamics.

    PubMed

    Swanson, Stanley M

    2011-08-01

    Classical electrodynamics has some annoying rough edges. The self-energy of charges is infinite without a cutoff. The calculation of relativistic trajectories is difficult because of retardation and an average radiation reaction term. By reconceptuallizing electrodynamics in terms of exchanges of impulses rather than describing it by forces and potentials, we eliminate these problems. A fully relativistic theory using photonlike null impulses is developed. Numerical calculations for a two-body, one-impulse-in-transit model are discussed. A simple relationship between center-of-mass scattering angle and angular momentum was found. It reproduces the Rutherford cross section at low velocities and agrees with the leading term of relativistic distinguishable-particle quantum cross sections (Møller, Mott) when the distance of closest approach is larger than the Compton wavelength of the particle. Magnetism emerges as a consequence of viewing retarded and advanced interactions from the vantage point of an instantaneous radius vector. Radiation reaction becomes the local conservation of energy-momentum between the radiating particle and the emitted impulse. A net action is defined that could be used in developing quantum dynamics without potentials. A reinterpretation of Newton's laws extends them to relativistic motion.

  19. Impulse radar studfinder

    DOEpatents

    McEwan, T.E.

    1995-10-10

    An impulse radar studfinder propagates electromagnetic pulses and detects reflected pulses from a fixed range. Unmodulated pulses, about 200 ps wide, are emitted. A large number of reflected pulses are sampled and averaged. Background reflections are subtracted. Reflections from wall studs or other hidden objects are detected and displayed using light emitting diodes. 9 figs.

  20. Impulse radar studfinder

    DOEpatents

    McEwan, Thomas E.

    1995-01-01

    An impulse radar studfinder propagates electromagnetic pulses and detects reflected pulses from a fixed range. Unmodulated pulses, about 200 ps wide, are emitted. A large number of reflected pulses are sampled and averaged. Background reflections are subtracted. Reflections from wall studs or other hidden objects are detected and displayed using light emitting diodes.

  1. Annoyance of helicopter impulsive noise

    NASA Technical Reports Server (NTRS)

    Dambra, F.; Damongeot, A.

    1978-01-01

    Psychoacoustic studies of helicopter impulsive noise were conducted in order to qualify additional annoyance due to this feature and to develop physical impulsiveness descriptors to develop impulsivity correction methods. The currently proposed descriptors and methods of impulsiveness correction are compared using a multilinear regression analysis technique. It is shown that the presently recommended descriptor and correction method provides the best correlation with the subjective evaluations of real helicopter impulsive noises. The equipment necessary for data processing in order to apply the correction method is discussed.

  2. Impulsive action and impulsive choice across substance and behavioral addictions: cause or consequence?

    PubMed

    Grant, Jon E; Chamberlain, Samuel R

    2014-11-01

    Substance use disorders are prevalent and debilitating. Certain behavioral syndromes ('behavioral addictions') characterized by repetitive habits, such as gambling disorder, stealing, shopping, and compulsive internet use, may share clinical, co-morbid, and neurobiological parallels with substance addictions. This review considers overlap between substance and behavioral addictions with a particular focus on impulsive action (inability to inhibit motor responses), and impulsive choice (preference for immediate smaller rewards to the detriment of long-term outcomes). We find that acute consumption of drugs with abuse potential is capable of modulating impulsive choice and action, although magnitude and direction of effect appear contingent on baseline function. Many lines of evidence, including findings from meta-analyses, show an association between chronic drug use and elevated impulsive choice and action. In some instances, elevated impulsive choice and action have been found to predate the development of substance use disorders, perhaps signifying their candidacy as objective vulnerability markers. Research in behavioral addictions is preliminary, and has mostly focused on impulsive action, finding this to be elevated versus controls, similar to that seen in chronic substance use disorders. Only a handful of imaging studies has explored the neural correlates of impulsive action and choice across these disorders. Key areas for future research are highlighted along with potential implications in terms of neurobiological models and treatment. In particular, future work should further explore whether the cognitive deficits identified are state or trait in nature: i.e. are evident before addiction perhaps signaling risk; or are a consequence of repetitive engagement in habitual behavior; and effects of novel agents known to modulate these cognitive abilities on various addictive disorders.

  3. Radical prostatectomy - discharge

    MedlinePlus

    ... prostatectomy - discharge; Laparoscopic radical prostatectomy - discharge; LRP - discharge; Robotic-assisted laparoscopic prostatectomy - discharge ; RALP - discharge; Pelvic lymphadenectomy - discharge; Prostate cancer - prostatectomy

  4. Time-resolved imaging of millimeter waves using visible continuum from the positive column of a Cs-Xe dc discharge

    NASA Astrophysics Data System (ADS)

    Gitlin, M. S.; Golovanov, V. V.; Spivakov, A. G.; Tsvetkov, A. I.; Zelenogorskiy, V. V.

    2010-03-01

    We present a high-sensitivity technique for time-resolved imaging of millimeter waves (MMWs) using the visible continuum (VC) from the positive column (PC) of a medium-pressure Cs-Xe dc discharge. For the MMW imaging application, a uniform plasma slab of the PC of a Cs-Xe discharge with 10×8 cm2 aperture and 2 cm in thickness was generated for 45 Torr xenon. The imaging technique is based on the fact that the intensity of the e-Xe bremsstrahlung continuum from the PC increases in the visible region when the electrons in the plasma are heated by MMWs. It is shown that in the MMW intensity range from zero to the threshold of the microwave-induced plasma breakdown, the intensity of the VC from the PC of a Cs-Xe discharge increases approximately as a second-order polynomial function of the MMW intensity. The obtained experimental data agree well with our calculations of the dependence of the VC intensity on electron temperature. The Ka-band MMW field patterns at the output of conical horn antennas and in the quasioptical beam were imaged using the discharge technique. It is shown that the technique can be used for time-resolved measurement of the profiles of watt- and subwatt-level MMWs. An energy flux sensitivity of the technique of about 10 μJ/cm2 in the Ka-band was demonstrated. The temporal resolution of the technique is about 0.8 μs. Our modeling of the transient behavior of the electron temperature in the PC shows that the time history of the electron temperature variation coincides well with the measured time history of the VC intensity variation.

  5. Vaginal Discharge

    MedlinePlus

    ... also be on the lookout for symptoms of yeast infections, bacterial vaginosis and trichomoniasis, 3 infections that ... cause changes in your vaginal discharge.Signs of yeast infectionsWhite, cottage cheese-like dischargeSwelling and pain around ...

  6. Impulse pumping modelling and simulation

    NASA Astrophysics Data System (ADS)

    Pierre, B.; Gudmundsson, J. S.

    2010-08-01

    Impulse pumping is a new pumping method based on propagation of pressure waves. Of particular interest is the application of impulse pumping to artificial lift situations, where fluid is transported from wellbore to wellhead using pressure waves generated at wellhead. The motor driven element of an impulse pumping apparatus is therefore located at wellhead and can be separated from the flowline. Thus operation and maintenance of an impulse pump are facilitated. The paper describes the different elements of an impulse pumping apparatus, reviews the physical principles and details the modelling of the novel pumping method. Results from numerical simulations of propagation of pressure waves in water-filled pipelines are then presented for illustrating impulse pumping physical principles, and validating the described modelling with experimental data.

  7. Intelligent detection of impulse noise using multilayer neural network with multi-valued neurons

    NASA Astrophysics Data System (ADS)

    Aizenberg, Igor; Wallace, Glen

    2012-03-01

    In this paper, we solve the impulse noise detection problem using an intelligent approach. We use a multilayer neural network based on multi-valued neurons (MLMVN) as an intelligent impulse noise detector. MLMVN was already used for point spread function identification and intelligent edge enhancement. So it is very attractive to apply it for solving another image processing problem. The main result, which is presented in the paper, is the proven ability of MLMVN to detect impulse noise on different images after a learning session with the data taken just from a single noisy image. Hence MLMVN can be used as a robust impulse detector. It is especially efficient for salt and pepper noise detection and outperforms all competitive techniques. It also shows comparable results in detection of random impulse noise. Moreover, for random impulse noise detection, MLMVN with the output neuron with a periodic activation function is used for the first time.

  8. Non-destructive monitoring of charge-discharge cycles on lithium ion batteries using ⁷Li stray-field imaging.

    PubMed

    Tang, Joel A; Dugar, Sneha; Zhong, Guiming; Dalal, Naresh S; Zheng, Jim P; Yang, Yong; Fu, Riqiang

    2013-01-01

    Magnetic resonance imaging provides a noninvasive method for in situ monitoring of electrochemical processes involved in charge/discharge cycling of batteries. Determining how the electrochemical processes become irreversible, ultimately resulting in degraded battery performance, will aid in developing new battery materials and designing better batteries. Here we introduce the use of an alternative in situ diagnostic tool to monitor the electrochemical processes. Utilizing a very large field-gradient in the fringe field of a magnet, stray-field-imaging (STRAFI) technique significantly improves the image resolution. These STRAFI images enable the real time monitoring of the electrodes at a micron level. It is demonstrated by two prototype half-cells, graphite∥Li and LiFePO₄∥Li, that the high-resolution (7)Li STRAFI profiles allow one to visualize in situ Li-ions transfer between the electrodes during charge/discharge cyclings as well as the formation and changes of irreversible microstructures of the Li components, and particularly reveal a non-uniform Li-ion distribution in the graphite.

  9. Comparison of acoustic radiation force impulse imaging and transient elastography for non-invasive assessment of liver fibrosis in patients with chronic hepatitis B.

    PubMed

    Zhang, Dakun; Chen, Min; Wang, Ruifang; Liu, Yang; Zhang, Dedong; Liu, Liping; Zhou, Guangde

    2015-01-01

    The aims of this study were to compare the performance of acoustic radiation force impulse (ARFI) elastography and transient elastography (TE) in the assessment of liver fibrosis in patients with chronic hepatitis B and to evaluate the impact of elevated alanine transaminase levels on liver stiffness assessment using ARFI elastography. One hundred eighty consecutive patients with chronic hepatitis B were enrolled in this study and evaluated with respect to histologic and biochemical features. All patients underwent ARFI elastography and TE. ARFI elastography and TE correlated significantly with histologically assessed fibrosis (r = 0.599, p < 0.001, for ARFI elastography; r = 0.628, p < 0.001, for TE) and necro-inflammatory activity (r = 0.591, p < 0.001, for ARFI elastography; r = 0.616, p < 0.001, for TE). Areas under the receiver operating characteristic curves for ARFI elastography and TE were 0.764 and 0.813 (p = 0.302, ≥stage 2), 0.852 and 0.852 (p = 1.000, ≥stage 3) and 0.825 and 0.799 (p = 0.655, S = 4), respectively. The optimum cutoff values for ARFI elastography were 1.63 m/s for stage ≥2, 1.74 m/s for stage ≥3 and 2.00 m/s for stage 4 in patients for whom alanine transaminase levels were evaluated. The cutoff values decreased to 1.24 m/s for ≥ stage 2, 1.32 m/s for ≥ stage 3 and 1.41 m/s for stage 4 in patients with normal alanine transaminase levels. ARFI elastography may be a reliable method for diagnosing the stage of liver fibrosis with diagnostic performance similar to that of TE in patients with chronic hepatitis B. In addition, liver stiffness values obtained with ARFI elastography, like those obtained with TE, may be influenced by alanine transaminase levels.

  10. Modeling of the Reactive High Power Impulse Magnetron Sputtering (HiPIMS) process

    NASA Astrophysics Data System (ADS)

    Gudmundsson, Jon Tomas; Lundin, Daniel; Raadu, Michael; Brenning, Nils; Minea, Tiberiu

    2015-09-01

    Reactive high power impulse magnetron sputtering (HiPIMS) provides both a high ionization fraction of the sputtered material and a high dissociation fraction of the molecular gas. We demonstrate this through an ionization region model (IRM) of the reactive Ar/O2 HiPIMS discharge with a titanium target. We explore the influence of oxygen dilution on the discharge properties such as electron density, the ionization fraction of the sputtered vapor and the oxygen dissociation fraction. We discuss the important processes and challenges for more detailed modeling of the reactive HiPIMS discharge. Furthermore, we discuss experimental observations during reactive high power impulse magnetron sputtering sputtering (HiPIMS) of Ti target in Ar/N2 and Ar/O2 atmosphere. The discharge current waveform is highly dependent on the reactive gas flow rate, pulse repetition frequency and discharge voltage. The discharge current increases with decreasing repetition frequency and increasing flowrate of the reactive gas.

  11. IMPULSIVITY PARAMETER FOR SOLAR FLARES

    SciTech Connect

    Fajardo-Mendieta, W. G.; Alvarado-Gómez, J. D.; Calvo-Mozo, B.; Martinez-Oliveros, J. C. E-mail: bcalvom@unal.edu.co E-mail: jalvarad@eso.org

    2016-02-10

    Three phases are typically observed during solar flares: the preflare, impulsive, and decay phases. During the impulsive phase, it is believed that the electrons and other particles are accelerated after the stored energy in the magnetic field is released by reconnection. The impulsivity of a solar flare is a quantifiable property that shows how quickly this initial energy release occurs. It is measured via the impulsivity parameter, which we define as the inverse of the overall duration of the impulsive phase. We take the latter as the raw width of the most prominent nonthermal emission of the flare. We computed this observable over a work sample of 48 M-class events that occurred during the current Solar Cycle 24 by using three different methods. The first method takes into account all of the nonthermal flare emission and gives very accurate results, while the other two just cover fixed energy intervals (30–40 keV and 25–50 keV) and are useful for fast calculations. We propose an alternative way to classify solar flares according to their impulsivity parameter values, defining three different types of impulsivity, namely, high, medium, and low. This system of classification is independent of the manner used to calculated the impulsivity parameter. Lastly, we show the relevance of this tool as a discriminator of different HXR generation processes.

  12. Teaching about Impulse and Momentum

    ERIC Educational Resources Information Center

    Franklin, Bill

    2004-01-01

    This American Association of Physics Teachers/Physics Teaching Resource Agents (APPT/PTRA) spiral-bound manual features labs and demos physics teachers can use to give students hands-on opportunities to learn about impulse and momentum. "Make-and-take activities" include AAPT Apparatus Contest winners "An Air Impulse Rocket," "A Fan Driven…

  13. Cigarette Cravings, Impulsivity, and the Brain

    PubMed Central

    Potvin, Stéphane; Tikàsz, Andràs; Dinh-Williams, Laurence Lê-Anh; Bourque, Josiane; Mendrek, Adrianna

    2015-01-01

    Craving is a core feature of tobacco use disorder as well as a significant predictor of smoking relapse. Studies have shown that appetitive smoking-related stimuli (e.g., someone smoking) trigger significant cravings in smokers impede their self-control capacities and promote drug seeking behavior. In this review, we begin by an overview of functional magnetic resonance imaging (fMRI) studies investigating the neural correlates of smokers to appetitive smoking cues. The literature reveals a complex and vastly distributed neuronal network underlying smokers’ craving response that recruits regions involved in self-referential processing, planning/regulatory processes, emotional responding, attentional biases, and automatic conducts. We then selectively review important factors contributing to the heterogeneity of results that significantly limit the implications of these findings, namely between- (abstinence, smoking expectancies, and self-regulation) and within-studies factors (severity of smoking dependence, sex-differences, motivation to quit, and genetic factors). Remarkably, we found that little to no attention has been devoted to examine the influence of personality traits on the neural correlates of cigarette cravings in fMRI studies. Impulsivity has been linked with craving and relapse in substance and tobacco use, which prompted our research team to examine the influence of impulsivity on cigarette cravings in an fMRI study. We found that the influence of impulsivity on cigarette cravings was mediated by fronto-cingulate mechanisms. Given the high prevalence of cigarette smoking in several psychiatric disorders that are characterized by significant levels of impulsivity, we conclude by identifying psychiatric patients as a target population whose tobacco-smoking habits deserve further behavioral and neuro-imaging investigation. PMID:26441686

  14. Anti-reflux surgery - discharge

    MedlinePlus

    ... fundoplication - discharge; Toupet fundoplication - discharge; Thal fundoplication - discharge; Hiatal hernia repair - discharge; Endoluminal fundoplication - discharge; GERD - fundoplication discharge; ...

  15. Impulsive control for hypervelocity missiles

    NASA Astrophysics Data System (ADS)

    Magness, R. W.

    1981-05-01

    A hypervelocity agile interceptor/quickshot is being developed for defense of ballistic missile launch sites. A guidance and control system is required to achieve the missile guidance accuracy necessary for direct target impact. Attitude control systems evaluated for the agile interceptor included aerodynamic controls, thrust vector controls and impulsive motor controls. The solid squib impulsive control motion was selected because of high response rate, low weight and low volume. A baseline motor configuration was designed and a solid propellant squib was developed for use in the control system. Ballistic pendulum and bench tests were conducted with a test impulsive control motor to measure nominal performance, establish the standard deviation of performance, and define requirements to prevent sympathetic ignition. A dynamic control wind tunnel test was also conducted to determine the impulse augmentation due to the impulsive motor jet interaction with the missile boundary layer. The degree and direction of augmentation was measured for variations in Mach number and angle of attack.

  16. Right ventromedial prefrontal cortex: a neuroanatomical correlate of impulse control in boys.

    PubMed

    Boes, Aaron D; Bechara, Antoine; Tranel, Daniel; Anderson, Steve W; Richman, Lynn; Nopoulos, Peg

    2009-03-01

    Emerging data on the neural mechanisms of impulse control highlight brain regions involved in emotion and decision making, including the ventromedial prefrontal cortex (vmPFC), anterior cingulate cortex (ACC) and amygdala. Variation in the development of these regions may influence one's propensity for impulsivity and, by extension, one's vulnerability to disorders involving low impulse control (e.g. substance abuse). Here we test the hypothesis that lower impulse control is associated with structural differences in these regions, particularly on the right side, in 61 normal healthy boys aged 7-17. We assessed parent- and teacher-reported behavioral ratings of impulse control (motor impulsivity and non-planning behavior) in relation to vmPFC, ACC and amygdala volume, measured using structural magnetic resonance imaging and FreeSurfer. A regression analysis showed that the right vmPFC was a significant predictor of impulse control ratings. Follow-up tests showed (i) a significant correlation between low impulse control and decreased right vmPFC volume, especially the medial sector of the vmPFC and (ii) significantly lower right vmPFC volume in a subgroup of 20 impulsive boys relative to 20 non-impulsive boys. These results are consistent with the notion that right vmPFC provides a neuroanatomical correlate of the normal variance in impulse control observed in boys.

  17. Bone marrow transplant - discharge

    MedlinePlus

    Transplant - bone marrow - discharge; Stem cell transplant - discharge; Hematopoietic stem cell transplant - discharge; Reduced intensity; Non-myeloablative transplant - discharge; Mini transplant - discharge; Allogenic bone marrow transplant - ...

  18. The nature of impulsivity: visual exposure to natural environments decreases impulsive decision-making in a delay discounting task.

    PubMed

    Berry, Meredith S; Sweeney, Mary M; Morath, Justice; Odum, Amy L; Jordan, Kerry E

    2014-01-01

    The benefits of visual exposure to natural environments for human well-being in areas of stress reduction, mood improvement, and attention restoration are well documented, but the effects of natural environments on impulsive decision-making remain unknown. Impulsive decision-making in delay discounting offers generality, predictive validity, and insight into decision-making related to unhealthy behaviors. The present experiment evaluated differences in such decision-making in humans experiencing visual exposure to one of the following conditions: natural (e.g., mountains), built (e.g., buildings), or control (e.g., triangles) using a delay discounting task that required participants to choose between immediate and delayed hypothetical monetary outcomes. Participants viewed the images before and during the delay discounting task. Participants were less impulsive in the condition providing visual exposure to natural scenes compared to built and geometric scenes. Results suggest that exposure to natural environments results in decreased impulsive decision-making relative to built environments.

  19. IPD -The Use of Impulse Plasma in Surface Engineering

    NASA Astrophysics Data System (ADS)

    Zdunek, Krzysztof

    2008-10-01

    It is evident that impulse plasma ensures both the highest level of nonequilibrity and highest level of vapour ionisation. These conditions seemed to be especially suitable for synthetizing the phases with high energetic barrier of nucleation process. In our methods, called by us as the Impulse Plasma Deposition (IPD) the impulse plasma is generated and accelerated in a coaxial accelerator. The only source of electric energy in the plasma process is condenser battery charged to the voltage of order of kVs. During the discharge of condensers individual plasmoids are being accelerated in the coaxial generator by the Ampere force to the speed of the order of 10^4 ms-1 and directed to the non-heated substrate. The most characteristic feature of the is that the synthesis proceeds in the impulse plasma itself, with the participation of ions. The crystallization on ions (ionization degree of the impulse plasma is equal to 100%) makes individual plasmoids to be strongly enriched rather in clusters or particles agglomerates with dimensions of order of single nms than the atoms. Because of the very short life time of plasmoids (approx. 10-4 sec each) the surface coalescence of particles delivered to the substrate has a limited character. As a consequence the material of the layer has nanocrystalline, globular morphology.

  20. Variable Specific Impulse Magnetoplasma Rocket Engine

    NASA Technical Reports Server (NTRS)

    Chang-Diaz, Franklin R. (Inventor)

    2002-01-01

    An engine is disclosed, including a controllable output plasma generator, a controllable heater for selectably raising a temperature of the plasma connected to an outlet of the plasma generator, and a nozzle connected to an outlet of the heater, through which heated plasma is discharged to provide thrust. In one embodiment, the source of plasma is a helicon generator. In one embodiment, the heater is an ion cyclotron resonator. In one embodiment, the nozzle is a radially diverging magnetic field disposed on a discharge side of the heater so that helically travelling particles in the beater exit the heater at high axial velocity. A particular embodiment includes control circuits for selectably directing a portion of radio frequency power from an RF generator to the helicon generator and to the cyclotron resonator so that the thrust output and the specific impulse of the engine can be selectively controlled. A method of propelling a vehicle is also disclosed. The method includes generating a plasma, heating said plasma, and discharging the heated plasma through a nozzle. In one embodiment, the nozzle is a diverging magnetic field. In this embodiment, the heating is performed by applying a radio frequency electro magnetic field to the plasma at the ion cyclotron frequency in an axially polarized DC magnetic field.

  1. Reactive high power impulse magnetron sputtering

    NASA Astrophysics Data System (ADS)

    Gudmundsson, J. T.; Magnus, F.; Tryggvason, T. K.; Sveinsson, O. B.; Olafsson, S.

    2012-10-01

    Here we discuss reactive high power impulse magnetron sputtering sputtering (HiPIMS) [1] of Ti target in an Ar/N2 and Ar/O2 atmosphere. The discharge current waveform is highly dependent on both the pulse repetition frequency and discharge voltage. The discharge current increases with decreasing frequency or voltage. This we attribute to an increase in the secondary electron emission yield during the self-sputtering phase of the pulse, as nitride [2] or oxide [3] forms on the target. We also discuss the growth of TiN films on SiO2 at temperatures of 22-600 ^oC. The HiPIMS process produces denser films at lower growth temperature and the surface is much smoother and have a significantly lower resistivity than dc magnetron sputtered films on SiO2 at all growth temperatures due to reduced grain boundary scattering [4].[4pt] [1] J. T. Gudmundsson, N. Brenning, D. Lundin and U. Helmersson, J. Vac. Sci. Technol. A, 30 030801 (2012)[0pt] [2] F. Magnus, O. B. Sveinsson, S. Olafsson and J. T. Gudmundsson, J. Appl. Phys., 110 083306 (2011)[0pt] [3] F. Magnus, T. K. Tryggvason, S. Olafsson and J. T. Gudmundsson, J. Vac. Sci. Technol., submitted 2012[0pt] [4] F. Magnus, A. S. Ingason, S. Olafsson and J. T. Gudmundsson, IEEE Elec. Dev. Lett., accepted 2012

  2. Helicon plasma thruster discharge model

    SciTech Connect

    Lafleur, T.

    2014-04-15

    By considering particle, momentum, and energy balance equations, we develop a semi-empirical quasi one-dimensional analytical discharge model of radio-frequency and helicon plasma thrusters. The model, which includes both the upstream plasma source region as well as the downstream diverging magnetic nozzle region, is compared with experimental measurements and confirms current performance levels. Analysis of the discharge model identifies plasma power losses on the radial and back wall of the thruster as the major performance reduction factors. These losses serve as sinks for the input power which do not contribute to the thrust, and which reduce the maximum plasma density and hence propellant utilization. With significant radial plasma losses eliminated, the discharge model (with argon) predicts specific impulses in excess of 3000 s, propellant utilizations above 90%, and thruster efficiencies of about 30%.

  3. Non-uniform temperature distribution in Li-ion batteries during discharge - A combined thermal imaging, X-ray micro-tomography and electrochemical impedance approach

    NASA Astrophysics Data System (ADS)

    Robinson, James B.; Darr, Jawwad A.; Eastwood, David S.; Hinds, Gareth; Lee, Peter D.; Shearing, Paul R.; Taiwo, Oluwadamilola O.; Brett, Dan J. L.

    2014-04-01

    Thermal runaway is a major cause of failure in Li-ion batteries (LIBs), and of particular concern for high energy density transport applications, where safety concerns have hampered commercialisation. A clear understanding of electro-thermal properties and how these relate to structure and operation is vital to improving thermal management of LIBs. Here a combined thermal imaging, X-ray tomography and electrochemical impedance spectroscopy (EIS) approach was applied to commercially available 18650 cells to study their thermal characteristics. Thermal imaging was used to characterise heterogeneous temperature distributions during discharge above 0.75C; the complementary information provided by 3D X-ray tomography was utilised to evaluate the internal structure of the battery and identify the regions causing heating, specifically the components of the battery cap.

  4. Reflection impulsivity in binge drinking: behavioural and volumetric correlates

    PubMed Central

    Banca, Paula; Lange, Iris; Worbe, Yulia; Howell, Nicholas A.; Irvine, Michael; Harrison, Neil A.; Moutoussis, Michael

    2015-01-01

    Abstract The degree to which an individual accumulates evidence prior to making a decision, also known as reflection impulsivity, can be affected in psychiatric disorders. Here, we study decisional impulsivity in binge drinkers, a group at elevated risk for developing alcohol use disorders, comparing two tasks assessing reflection impulsivity and a delay discounting task, hypothesizing impairments in both subtypes of impulsivity. We also assess volumetric correlates of reflection impulsivity focusing on regions previously implicated in functional magnetic resonance imaging studies. Sixty binge drinkers and healthy volunteers were tested using two different information‐gathering paradigms: the beads task and the Information Sampling Task (IST). The beads task was analysed using a behavioural approach and a Bayesian model of decision making. Delay discounting was assessed using the Monetary Choice Questionnaire. Regression analyses of primary outcomes were conducted with voxel‐based morphometry analyses. Binge drinkers sought less evidence prior to decision in the beads task compared with healthy volunteers in both the behavioural and computational modelling analysis. There were no group differences in the IST or delay discounting task. Greater impulsivity as indexed by lower evidence accumulation in the beads task was associated with smaller dorsolateral prefrontal cortex and inferior parietal volumes. In contrast, greater impulsivity as indexed by lower evidence accumulation in the IST was associated with greater dorsal cingulate and precuneus volumes. Binge drinking is characterized by impaired reflection impulsivity suggesting a deficit in deciding on the basis of future outcomes that are more difficult to represent. These findings emphasize the role of possible therapeutic interventions targeting decision‐making deficits. PMID:25678093

  5. Reflection impulsivity in binge drinking: behavioural and volumetric correlates.

    PubMed

    Banca, Paula; Lange, Iris; Worbe, Yulia; Howell, Nicholas A; Irvine, Michael; Harrison, Neil A; Moutoussis, Michael; Voon, Valerie

    2016-03-01

    The degree to which an individual accumulates evidence prior to making a decision, also known as reflection impulsivity, can be affected in psychiatric disorders. Here, we study decisional impulsivity in binge drinkers, a group at elevated risk for developing alcohol use disorders, comparing two tasks assessing reflection impulsivity and a delay discounting task, hypothesizing impairments in both subtypes of impulsivity. We also assess volumetric correlates of reflection impulsivity focusing on regions previously implicated in functional magnetic resonance imaging studies. Sixty binge drinkers and healthy volunteers were tested using two different information-gathering paradigms: the beads task and the Information Sampling Task (IST). The beads task was analysed using a behavioural approach and a Bayesian model of decision making. Delay discounting was assessed using the Monetary Choice Questionnaire. Regression analyses of primary outcomes were conducted with voxel-based morphometry analyses. Binge drinkers sought less evidence prior to decision in the beads task compared with healthy volunteers in both the behavioural and computational modelling analysis. There were no group differences in the IST or delay discounting task. Greater impulsivity as indexed by lower evidence accumulation in the beads task was associated with smaller dorsolateral prefrontal cortex and inferior parietal volumes. In contrast, greater impulsivity as indexed by lower evidence accumulation in the IST was associated with greater dorsal cingulate and precuneus volumes. Binge drinking is characterized by impaired reflection impulsivity suggesting a deficit in deciding on the basis of future outcomes that are more difficult to represent. These findings emphasize the role of possible therapeutic interventions targeting decision-making deficits.

  6. The Neurobiology of Impulsive Aggression.

    PubMed

    Blair, Robert J R

    2016-02-01

    This selective review provides a model of the neurobiology of impulsive aggression from a cognitive neuroscience perspective. It is argued that prototypical cases of impulsive aggression, those associated with anger, involve the recruitment of the acute threat response system structures; that is, the amygdala, hypothalamus, and periaqueductal gray. It is argued that whether the recruitment of these structures results in impulsive aggression or not reflects the functional roles of ventromedial frontal cortex and dorsomedial frontal and anterior insula cortex in response selection. It is also argued that impulsive aggression may occur because of impaired decision making. The aggression may not be accompanied by anger, but it will reflect disrupted evaluation of the rewards/benefits of the action.

  7. The Neurobiology of Impulsive Aggression

    PubMed Central

    2016-01-01

    Abstract This selective review provides a model of the neurobiology of impulsive aggression from a cognitive neuroscience perspective. It is argued that prototypical cases of impulsive aggression, those associated with anger, involve the recruitment of the acute threat response system structures; that is, the amygdala, hypothalamus, and periaqueductal gray. It is argued that whether the recruitment of these structures results in impulsive aggression or not reflects the functional roles of ventromedial frontal cortex and dorsomedial frontal and anterior insula cortex in response selection. It is also argued that impulsive aggression may occur because of impaired decision making. The aggression may not be accompanied by anger, but it will reflect disrupted evaluation of the rewards/benefits of the action. PMID:26465707

  8. Impulsive control for fast nanopositioning.

    PubMed

    Tuma, Tomas; Sebastian, Abu; Häberle, Walter; Lygeros, John; Pantazi, Angeliki

    2011-04-01

    In this paper we present a non-linear control scheme for high-speed nanopositioning based on impulsive control. Unlike in the case of a linear feedback controller, the controller states are altered in a discontinuous manner at specific instances in time. Using this technique, it is possible to simultaneously achieve good tracking performance, disturbance rejection and tolerance to measurement noise. Impulsive control is demonstrated experimentally on an atomic force microscope. A significant improvement in tracking performance is demonstrated.

  9. Serotonergic modulation of ‘waiting impulsivity' is mediated by the impulsivity phenotype in humans

    PubMed Central

    Neufang, S; Akhrif, A; Herrmann, C G; Drepper, C; Homola, G A; Nowak, J; Waider, J; Schmitt, A G; Lesch, K-P; Romanos, M

    2016-01-01

    In rodents, the five-choice serial reaction time task (5-CSRTT) has been established as a reliable measure of waiting impulsivity being defined as the ability to regulate a response in anticipation of reinforcement. Key brain structures are the nucleus accumbens (NAcc) and prefrontal regions (for example, pre- and infralimbic cortex), which are, together with other transmitters, modulated by serotonin. In this functional magnetic resonance imaging study, we examined 103 healthy males while performing the 5-CSRTT measuring brain activation in humans by means of a paradigm that has been widely applied in rodents. Subjects were genotyped for the tryptophan hydroxylase-2 (TPH2; G-703T; rs4570625) variant, an enzyme specific for brain serotonin synthesis. We addressed neural activation patterns of waiting impulsivity and the interaction between the NAcc and the ventromedial prefrontal cortex (vmPFC) using dynamic causal modeling. Genetic influence was examined via interaction analyses between the TPH2 genotype (GG homozygotes vs T allele carriers) and the degree of impulsivity as measured by the 5-CSRTT. We found that the driving input of the vmPFC was reduced in highly impulsive T allele carriers (reflecting a reduced top-down control) in combination with an enhanced response in the NAcc after correct target processing (reflecting an augmented response to monetary reward). Taken together, we found a high overlap of our findings with reports from animal studies in regard to the underlying cognitive processes, the brain regions associated with waiting impulsivity and the neural interplay between the NAcc and vmPFC. Therefore, we conclude that the 5-CSRTT is a promising tool for translational studies. PMID:27824354

  10. Impulsivity, risk taking, and timing.

    PubMed

    Baumann, Ana A; Odum, Amy L

    2012-07-01

    This study examined the relations among measures of impulsivity and timing. Impulsivity was assessed using delay and probability discounting, and self-report impulsivity (as measured by the Barratt Impulsiveness Scale; BIS-11). Timing was assessed using temporal perception as measured on a temporal bisection task and time perspective (as measured by the Zimbardo Time Perspective Inventory). One hundred and forty three college students completed these measures in a computer laboratory. The degree of delay discounting was positively correlated with the mean and range of the temporal bisection procedure. The degree of delay and probability discounting were also positively correlated. Self-reported motor impulsiveness on the BIS-11 was positively correlated with present hedonism and negatively correlated with future orientation on the ZTPI. Self-reported non-planning on the BIS-11 was positively correlated with fatalism on the ZTPI. These results show that people who overestimate the passage of time (perceive time as passing more quickly) hold less value in delayed rewards. They also confirm previous results regarding the relation between delay and probability discounting, as well as highlight similarities in self-report measures of impulsivity and time perspective.

  11. Impulsivity, Risk Taking, and Timing

    PubMed Central

    Baumann, Ana A.; Odum, Amy. L.

    2012-01-01

    This study examined the relations among measures of impulsivity and timing. Impulsivity was assessed using delay and probability discounting, and self-report impulsivity (as measured by the Barratt Impulsiveness Scale; BIS-11). Timing was assessed using temporal perception as measured on a temporal bisection task and time perspective (as measured by the Zimbardo Time Perspective Inventory). One hundred and forty three college students completed these measures in a computer laboratory. The degree of delay discounting was positively correlated with the mean and range of the temporal bisection procedure. The degree of delay and probability discounting were also positively correlated. Self-reported Motor impulsiveness on the BIS-11 was positively correlated with Present Hedonism and negatively correlated with Future orientation on the ZTPI. Self-reported Non-Planning on the BIS-11 was positively correlated with Fatalism on the ZTPI. These results show that people who overestimate the passage of time (perceive time as passing more quickly) hold less value in delayed rewards. They also confirm previous results regarding the relation between delay and probability discounting, as well as highlight similarities in self-report measures of impulsivity and time perspective. PMID:22542458

  12. A Test Study of 50% Lightning Impulse Breakdown Voltage on Rod-Plane Gap with Two-Phase Mixture of Gas and Solid Particles

    NASA Astrophysics Data System (ADS)

    He, Zhenghao; Xu, Huaili; Bai, Jing; Yu, Fusheng; Hu, Feng; Li, Jin

    2007-12-01

    A test study on 50% lightning impulse breakdown voltage in two-phase mixture of gas and solid particles has been carried out in a specially designed discharge cabinet. A mechanical sieve is set up for sifting different solid particles into the discharge space uniformly. The lightning impulse voltage according with international electro-technical commission (IEC) standard is applied to the electrodes inside the discharge cabinet by the rule of up-down method in a total of 40 times. The results showed that the 50% lightning impulse breakdown voltage in two-phase mixture of gas and solid particles has its own features and is much different from that in air.

  13. Septoplasty - discharge

    MedlinePlus

    ... this page: //medlineplus.gov/ency/patientinstructions/000246.htm Septoplasty - discharge To use the sharing features on this page, please enable JavaScript. Septoplasty is surgery to correct any problems in the ...

  14. Osteomyelitis - discharge

    MedlinePlus

    ... this page: //medlineplus.gov/ency/patientinstructions/000297.htm Osteomyelitis - discharge To use the sharing features on this page, please enable JavaScript. You have osteomyelitis , a bone infection caused by bacteria or other ...

  15. Cirrhosis - discharge

    MedlinePlus

    ... this page: //medlineplus.gov/ency/patientinstructions/000290.htm Cirrhosis - discharge To use the sharing features on this page, please enable JavaScript. You have cirrhosis of the liver. Scar tissue forms and your ...

  16. Solar Flare Impulsive Phase Emission Observed with SDO/EVE

    NASA Astrophysics Data System (ADS)

    Kennedy, Michael B.; Milligan, Ryan O.; Mathioudakis, Mihalis; Keenan, Francis P.

    2013-12-01

    Differential emission measures (DEMs) during the impulsive phase of solar flares were constructed using observations from the EUV Variability Experiment (EVE) and the Markov-Chain Monte Carlo method. Emission lines from ions formed over the temperature range log Te = 5.8-7.2 allow the evolution of the DEM to be studied over a wide temperature range at 10 s cadence. The technique was applied to several M- and X-class flares, where impulsive phase EUV emission is observable in the disk-integrated EVE spectra from emission lines formed up to 3-4 MK and we use spatially unresolved EVE observations to infer the thermal structure of the emitting region. For the nine events studied, the DEMs exhibited a two-component distribution during the impulsive phase, a low-temperature component with peak temperature of 1-2 MK, and a broad high-temperature component from 7 to 30 MK. A bimodal high-temperature component is also found for several events, with peaks at 8 and 25 MK during the impulsive phase. The origin of the emission was verified using Atmospheric Imaging Assembly images to be the flare ribbons and footpoints, indicating that the constructed DEMs represent the spatially average thermal structure of the chromospheric flare emission during the impulsive phase.

  17. Solar flare impulsive phase emission observed with SDO/EVE

    SciTech Connect

    Kennedy, Michael B.; Milligan, Ryan O.; Mathioudakis, Mihalis; Keenan, Francis P.

    2013-12-10

    Differential emission measures (DEMs) during the impulsive phase of solar flares were constructed using observations from the EUV Variability Experiment (EVE) and the Markov-Chain Monte Carlo method. Emission lines from ions formed over the temperature range log T{sub e} = 5.8-7.2 allow the evolution of the DEM to be studied over a wide temperature range at 10 s cadence. The technique was applied to several M- and X-class flares, where impulsive phase EUV emission is observable in the disk-integrated EVE spectra from emission lines formed up to 3-4 MK and we use spatially unresolved EVE observations to infer the thermal structure of the emitting region. For the nine events studied, the DEMs exhibited a two-component distribution during the impulsive phase, a low-temperature component with peak temperature of 1-2 MK, and a broad high-temperature component from 7 to 30 MK. A bimodal high-temperature component is also found for several events, with peaks at 8 and 25 MK during the impulsive phase. The origin of the emission was verified using Atmospheric Imaging Assembly images to be the flare ribbons and footpoints, indicating that the constructed DEMs represent the spatially average thermal structure of the chromospheric flare emission during the impulsive phase.

  18. Dynamic Initiator Experiments using IMPULSE (Impact system for Ultrafast Synchrotron Experiments) at the Advanced Photon Source

    NASA Astrophysics Data System (ADS)

    Sanchez, Nathaniel; Jensen, Brian; Ramos, Kyle; Iverson, Adam; Martinez, Michael; Liechty, Gary; Fezzaa, Kamel; Clarke, Steven

    2015-06-01

    We have successfully imaged, for the first time, the operation of copper slapper initiators that are used to initiate high explosive detonators. These data will aid in model development and calibration in order to provide a robust predictive capability and as a design tool in future applications. The initiation system consists of a copper bridge fixed to a parylene flyer. The copper bridge functions when a capacitor is discharged causing current to flow through the narrow bridge. As this happens, a plasma forms due to the high current densities and ohmic heating, which launches the parylene flyer that impacts a high explosive pellet producing detonation. Unlike traditional measurements, x-ray phase contrast imaging can see ``inside'' the process providing unique information with nanosecond time resolution and micrometer spatial resolution. The team performed experiments on the IMPULSE system at the Advanced Photon Source to obtain high resolution, in situ images of this process in real-time. From these images, researchers can examine the formation of the plasma instabilities and their interaction with the flyer, determine the flyer velocity, and obtain crucial information on the spatial distribution of mass and density gradients in the plasma and flyer.

  19. Energy deposition in discharge chamber of lightning protection multichamber system

    NASA Astrophysics Data System (ADS)

    Pinchuk, M. E.; Budin, A. V.; Kumkova, I. I.; Bogomaz, A. A.; Sivaev, A. D.; Chusov, A. N.; Zaynalov, R. I.

    2016-11-01

    The experimental data of energy deposition distribution along discharge chamber of lightning protection multichamber system in initial stage of discharge process aimed to model lightning current impulse up to 10 kA is presented. A multichamber system is a series connection of discharge chambers. According to our experiments the shock wave formation occurs during the breakdown phase between electrodes located at the bottom of discharge chamber. The consequent energy deposition during discharge development goes in the whole volume bounded by shock wave front.

  20. Cardiac catheterization - discharge

    MedlinePlus

    Catheterization - cardiac - discharge; Heart catheterization - discharge: Catheterization - cardiac; Heart catheterization; Angina - cardiac catheterization discharge; CAD - cardiac catheterization discharge; Coronary artery disease - cardiac catheterization ...

  1. Kidney removal - discharge

    MedlinePlus

    ... nephrectomy - discharge; Open nephrectomy - discharge; Laparoscopic nephrectomy - discharge; Partial nephrectomy - discharge ... Plan to have someone drive you home from the hospital. DO NOT drive yourself home. You may ...

  2. Atrial fibrillation - discharge

    MedlinePlus

    Auricular fibrillation - discharge; A-fib - discharge; AF - discharge; Afib - discharge ... been in the hospital because you have atrial fibrillation . This condition occurs when your heart beats faster ...

  3. RF micro-discharge thruster

    NASA Astrophysics Data System (ADS)

    Dunaevsky, Alexander; Fisch, Nathaniel

    2004-11-01

    Propulsion devices for spacecrafts with masses of several tens to one hundred kilograms are in an increasing demand. These devices should provide thrust of a few mN and specific impulse of about 1000 s at the total power consumption of several tens of W. In search of an alternative solution for lower power range, we investigated an rf discharge initiated in a sub-millimeter capillary fed by a gaseous propellant. In such a discharge, it is possible to heat plasma electrons up to temperatures of ˜ 20-30 eV. Steep density drop at the open end of the capillary should be a reason of the formation of a double layer, were the discharge ions are accelerated to energies of ˜5Te. A laboratory prototype demonstrated stable operation at the argon flow rate of 4-10 sccm. The discharge was powered by a 2 MHz rf generator. Power consumption of the discharge was about 16 W. Ionization rate was moderate due to nonoptimal electrode configuration, which resulted in the propellant utilization of 6-11%. Relatively wide plume angle of ˜130 degrees indicates that the acceleration region is placed outside the capillary and has a convex shape. Stability and parameters of the discharge depends on the material of the capillary channel. Among advantages of the rf micro-discharge thruster are simplicity, small size, and absence of cathode-neutralizer. Being optimized, the rf micro-discharge thruster seems very promising propulsion device for sub-mN thrust range.

  4. Facts and reflections on thalamocortical reverberation of impulses.

    PubMed

    Narikashvili, S P

    1976-01-01

    Experiments on cats, either unanesthetized or anesthetized with various doses of pentobarbital, showed that the cortical rhythmic after-discharge ("slow after-activity"), which has been regarded as a manifestation of reverberation of impulses in thalamocortical circuits [17], consists of a burst of spontaneous "spindles" evoked by stimulation. This conclusion is supported by the following facts: Spontaneous "spindles" and the rhythmic after-discharge respond absolutely identically (disappear) to activation of the EEG and deepening of pentobarbital anesthesia. The absence of thalamocortical reverberation is also indicated by the preservation of a rhythmic after-discharge (to clicks), synchronous with the cortex, in the thalamic relay nucleus (the medial geniculate body) after cooling or after removal of its projection zone.

  5. THz impulse radar for biomedical sensing: nonlinear system behavior

    NASA Astrophysics Data System (ADS)

    Brown, E. R.; Sung, Shijun; Grundfest, W. S.; Taylor, Z. D.

    2014-03-01

    The THz impulse radar is an "RF-inspired" sensor system that has performed remarkably well since its initial development nearly six years ago. It was developed for ex vivo skin-burn imaging, and has since shown great promise in the sensitive detection of hydration levels in soft tissues of several types, such as in vivo corneal and burn samples. An intriguing aspect of the impulse radar is its hybrid architecture which combines the high-peak-power of photoconductive switches with the high-responsivity and -bandwidth (RF and video) of Schottky-diode rectifiers. The result is a very sensitive sensor system in which the post-detection signal-to-noise ratio depends super-linearly on average signal power up to a point where the diode is "turned on" in the forward direction, and then behaves quasi-linearly beyond that point. This paper reports the first nonlinear systems analysis done on the impulse radar using MATLAB.

  6. Interactions between surface discharges induced by volume discharges in a dielectric barrier discharge system

    SciTech Connect

    Gao, Yenan; Dong, Lifang Zhao, Longhu; Wang, Yongjie; Pan, Yuyang; Li, Ben

    2014-10-15

    The interaction between micro-discharges involved in surface discharges (SDs) is studied in dielectric barrier discharge system. Instantaneous images taken by high speed cameras show that the SDs are induced by volume discharges (VDs). They cannot cross the midperpendicular of two neighbouring volume charges at low voltage while they stretch along it at high voltage, indicating that there is interaction between SDs. The differences of plasma parameters between SD and VD are studied by optical emission spectroscopy. The simulation of the electric fields of the wall charges accumulated by VD further confirms the existence of the interaction.

  7. Nipple Discharge

    MedlinePlus

    ... If the ultrasound shows a lesion within a milk duct, you may need a biopsy to confirm that it's a papilloma or to exclude a cancer. Nipple discharge is rarely a sign of breast cancer. But it might be a sign of ...

  8. Robust Lee local statistic filter for removal of mixed multiplicative and impulse noise

    NASA Astrophysics Data System (ADS)

    Ponomarenko, Nikolay N.; Lukin, Vladimir V.; Egiazarian, Karen O.; Astola, Jaakko T.

    2004-05-01

    A robust version of Lee local statistic filter able to effectively suppress the mixed multiplicative and impulse noise in images is proposed. The performance of the proposed modification is studied for a set of test images, several values of multiplicative noise variance, Gaussian and Rayleigh probability density functions of speckle, and different characteris-tics of impulse noise. The advantages of the designed filter in comparison to the conventional Lee local statistic filter and some other filters able to cope with mixed multiplicative+impulse noise are demonstrated.

  9. Features of application of image converter cameras for research on lightning and discharges in long air gaps

    NASA Astrophysics Data System (ADS)

    Lebedev, Vitaly B.; Feldman, Grigory G.; Gorin, Boris N.; Shcherbacov, Yuri V.; Syssoev, Vladimir S.; Rakov, Vladimir A.

    2005-03-01

    The present report generalizes materials of publication /1-3/. In doing so /1/ and /3/ were presented at appropriate symposiums only as poster reports and were not widely discussed. Creation of reliable physical and engineering models of sequence of leader-return stroke of lightning (L-RS) and an attachment process is hampered by lack of actual information on the optical picture of low-luminous streamer structures of lightning. Cameras based on an image converter tubes (ICT) /4/ serve as an alternative of traditional optical-mechanical means for recording a lightning image. Such cameras allowed to obtain new reults when investigating streamer processes of a long spark what made it possible to formulate a set of hypothesizes relating to a leader process of lightning /5-7/. Here there are given the characteristics of the image converter instrumentation complex adapted to the work with lightning and a long spark and there are presented the results of its tests in the All-Russian Electro-technical Institute (VEI) named after V.I. Lenin when recording a long spark on the open high-voltage stand in Istra (near Moscow).

  10. Trait Impulsivity and Newlyweds' Marital Trajectories.

    PubMed

    Lavner, Justin A; Lamkin, Joanna; Miller, Joshua D

    2017-02-01

    Despite the relationship of impulsivity with interpersonal dysfunction, including romantic relationship dysfunction, surprisingly little research has examined the degree to which impulsivity predicts how marriages unfold over time. The current study used data from 172 newlywed couples to examine spouses' impulsivity in relation to their 4-year trajectories of marital satisfaction, marital problems, relationship commitment, and verbal aggression, as well as their 10-year divorce rates. Hierarchical linear modeling indicated that husbands' and wives' impulsivity predicted their own intercepts of marital satisfaction and marital problems, reflecting lower levels of satisfaction and higher levels of problems. Wives' impulsivity also predicted their relationship commitment and their verbal aggression intercepts. No cross-spouse effects or effects on slopes were found, and impulsivity did not predict 10-year divorce rates. These findings indicate that the relationship distress associated with impulsivity begins early in marriage, and they suggest a need for further research on the processes by which impulsivity undermines marital quality.

  11. Children's Help Seeking and Impulsivity

    ERIC Educational Resources Information Center

    Puustinen, Minna; Kokkonen, Marja; Tolvanen, Asko; Pulkkinen, Lea

    2004-01-01

    The aim of the present study was to analyze the relationship between students' (100 children aged 8 to 12) help-seeking behavior and impulsivity. Help-seeking behavior was evaluated using a naturalistic experimental paradigm in which children were placed in a problem-solving situation and had the opportunity to seek help from the experimenter, if…

  12. Demonstrating Sound Impulses in Pipes.

    ERIC Educational Resources Information Center

    Raymer, M. G.; Micklavzina, Stan

    1995-01-01

    Describes a simple, direct method to demonstrate the effects of the boundary conditions on sound impulse reflections in pipes. A graphical display of the results can be made using a pipe, cork, small hammer, microphone, and fast recording electronics. Explains the principles involved. (LZ)

  13. Commentary on Hyperkinetic Impulse Disorder

    ERIC Educational Resources Information Center

    Barkley, Russell A.

    2011-01-01

    Dr. Goldstein continues the laudable practice of reprinting articles of historical significance in the history of ADHD with this selective reprinting of material from the original article by Maurice Laufer, Eric Denhoff, and Gerald Solomons on hyperkinetic impulsive disorder (HID) in children. This article on HID is among the first articles to…

  14. Baseline impulsive choice predicts the effects of nicotine and nicotine withdrawal on impulsivity in rats.

    PubMed

    Kayir, Hakan; Semenova, Svetlana; Markou, Athina

    2014-01-03

    Impulsive choice, a form of impulsivity, is associated with tobacco smoking in humans. Trait impulsivity may be a vulnerability factor for smoking, or smoking may lead to impulsive behaviors. We investigated the effects of 14-day nicotine exposure (6.32mg/kg/day base, subcutaneous minipumps) and spontaneous nicotine withdrawal on impulsive choice in low impulsive (LI) and high impulsive (HI) rats. Impulsive choice was measured in the delayed reward task in which rats choose between a small immediate reward and a large delayed reward. HI and LI rats were selected from the highest and lowest quartiles of the group before exposure to nicotine. In non-selected rats, nicotine or nicotine withdrawal had no effect on impulsive choice. In LI rats, chronic nicotine exposure decreased preference for the large reward with larger effects at longer delays, indicating increased impulsive choice. Impulsive choices for the smaller immediate rewards continued to increase during nicotine withdrawal in LI rats. In HI rats, nicotine exposure and nicotine withdrawal had no effect on impulsive choice, although there was a tendency for decreased preference for the large reward at short delays. These results indicate that nicotine- and nicotine withdrawal-induced increases in impulsive choice depend on trait impulsivity with more pronounced increases in impulsive choice in LI compared to HI subjects. Increased impulsivity during nicotine exposure may strengthen the addictive properties of nicotine and contribute to compulsive nicotine use.

  15. Adolescent Impulsivity: Findings from a Community Sample

    ERIC Educational Resources Information Center

    d'Acremont, Mathieu; Van der Linden, Martial

    2005-01-01

    Impulsivity is central to several psychopathological states in adolescence. However, there is little consensus concerning the definition of impulsivity and its core dimensions. In response to this lack of consensus, Whiteside and Lynam (2001, "Pers. Individ. Differ." 30, 669-689) have developed the UPPS Impulsive Behavior Scale, which is able to…

  16. Characteristics of Impulsive Suicide Attempts and Attempters.

    ERIC Educational Resources Information Center

    Simon, Thomas R.; Swann, Alan C.; Powell, Kenneth E.; Potter, Lloyd B.; Kresnow, Marcie-jo; O'Carroll, Patrick W.

    2002-01-01

    Examined impulsive suicide attempts within a population-based, case-control study of nearly lethal suicide attempts among adolescents and young adults. Impulsive attempts were more likely among those who had been in a physical fight and less likely among those who were depressed. Findings suggest inadequate control of aggressive impulses as a…

  17. Interaction between pulsed discharge and radio frequency discharge burst at atmospheric pressure

    SciTech Connect

    Zhang, Jie; Guo, Ying; Shi, Yuncheng; Zhang, Jing; Shi, J. J.

    2015-08-15

    The atmospheric pressure glow discharges (APGD) with dual excitations in terms of pulsed voltage and pulse-modulation radio frequency (rf) power are studied experimentally between two parallel plates electrodes. Pulse-modulation applied in rf APGD temporally separates the discharge into repetitive discharge bursts, between which the high voltage pulses are introduced to ignite sub-microsecond pulsed discharge. The discharge characteristics and spatio-temporal evolution are investigated by means of current voltage characteristics and time resolved imaging, which suggests that the introduced pulsed discharge assists the ignition of rf discharge burst and reduces the maintain voltage of rf discharge burst. Furtherly, the time instant of pulsed discharge between rf discharge bursts is manipulated to study the ignition dynamics of rf discharge burst.

  18. Impulse generation by detonation tubes

    NASA Astrophysics Data System (ADS)

    Cooper, Marcia Ann

    Impulse generation with gaseous detonation requires conversion of chemical energy into mechanical energy. This conversion process is well understood in rocket engines where the high pressure combustion products expand through a nozzle generating high velocity exhaust gases. The propulsion community is now focusing on advanced concepts that utilize non-traditional forms of combustion like detonation. Such a device is called a pulse detonation engine in which laboratory tests have proven that thrust can be achieved through continuous cyclic operation. Because of poor performance of straight detonation tubes compared to conventional propulsion systems and the success of using nozzles on rocket engines, the effect of nozzles on detonation tubes is being investigated. Although previous studies of detonation tube nozzles have suggested substantial benefits, up to now there has been no systematic investigations over a range of operating conditions and nozzle configurations. As a result, no models predicting the impulse when nozzles are used exist. This lack of data has severely limited the development and evaluation of models and simulations of nozzles on pulse detonation engines. The first experimental investigation measuring impulse by gaseous detonation in plain tubes and tubes with nozzles operating in varying environment pressures is presented. Converging, diverging, and converging-diverging nozzles were tested to determine the effect of divergence angle, nozzle length, and volumetric fill fraction on impulse. The largest increases in specific impulse, 72% at an environment pressure of 100 kPa and 43% at an environment pressure of 1.4 kPa, were measured with the largest diverging nozzle tested that had a 12° half angle and was 0.6 m long. Two regimes of nozzle operation that depend on the environment pressure are responsible for these increases and were first observed from these data. To augment this experimental investigation, all data in the literature regarding

  19. A new absolute extreme ultraviolet image system designed for studying the radiated power of the Joint Texas Experimental Tokamak discharges

    SciTech Connect

    Zhang, J.; Zhuang, G.; Wang, Z. J.; Ding, Y. H.; Zhang, X. Q.; Tang, Y. J.

    2010-07-15

    A bolometer imaging system mounted on different toroidal and poloidal locations used for radiation observation has been developed in the Joint Texas Experimental Tokamak (J-TEXT tokamak). Three miniature pinhole AXUV16ELG (16 elements absolute extreme ultraviolet silicon photodiodes) array cameras, which are settled down in the same toroidal position but in three different poloidal places, can provide a broad viewing angle that covers the whole plasma cross-section, and hence can measure the total radiated power and provide the radiated emissive profile, while nine AXUV10EL (10 elements absolute extreme ultraviolet silicon photodiodes) array cameras are divided into three groups and will be mounted on different toroidal locations to observe the toroidal radiated power distribution. Among these detectors, one element of the AXUV16ELG array is absolutely calibrated by the synchrotron radiation source to verify the system reliability. Although there are some discrepancies between the typical responsivity given by IRD Co. and the calibrated results, it is confirmed that the discrepancies have no major effect on the final result after the simulation. The details of the system as well as observations are presented in the paper.

  20. A new absolute extreme ultraviolet image system designed for studying the radiated power of the Joint Texas Experimental Tokamak discharges.

    PubMed

    Zhang, J; Zhuang, G; Wang, Z J; Ding, Y H; Zhang, X Q; Tang, Y J

    2010-07-01

    A bolometer imaging system mounted on different toroidal and poloidal locations used for radiation observation has been developed in the Joint Texas Experimental Tokamak (J-TEXT tokamak). Three miniature pinhole AXUV16ELG (16 elements absolute extreme ultraviolet silicon photodiodes) array cameras, which are settled down in the same toroidal position but in three different poloidal places, can provide a broad viewing angle that covers the whole plasma cross-section, and hence can measure the total radiated power and provide the radiated emissive profile, while nine AXUV10EL (10 elements absolute extreme ultraviolet silicon photodiodes) array cameras are divided into three groups and will be mounted on different toroidal locations to observe the toroidal radiated power distribution. Among these detectors, one element of the AXUV16ELG array is absolutely calibrated by the synchrotron radiation source to verify the system reliability. Although there are some discrepancies between the typical responsivity given by IRD Co. and the calibrated results, it is confirmed that the discrepancies have no major effect on the final result after the simulation. The details of the system as well as observations are presented in the paper.

  1. Hysterectomy - vaginal - discharge

    MedlinePlus

    Vaginal hysterectomy - discharge; Laparoscopically assisted vaginal hysterectomy - discharge; LAVH - discharge ... you were in the hospital, you had a vaginal hysterectomy. Your surgeon made a cut in your ...

  2. Tubal ligation - discharge

    MedlinePlus

    ... discharge; Tube tying - discharge; Tying the tubes - discharge; Contraception - tubal ... chap 23. Jensen JT, Mishell DR. Family planning: contraception, sterilization, and pregnancy termination. In: Lentz GM, Lobo ...

  3. SAR impulse response with residual chirps.

    SciTech Connect

    Doerry, Armin Walter

    2009-06-01

    A Linear Frequency-Modulated (LFM) chirp is a function with unit amplitude and quadratic phase characteristic. In a focused Synthetic Aperture Radar (SAR) image, a residual chirp is undesired for targets of interest, as it coarsens the manifested resolution. However, for undesired spurious signals, a residual chirp is often advantageous because it spreads the energy and thereby diminishes its peak value. In either case, a good understanding of the effects of a residual LFM chirp on a SAR Impulse Response (IPR) is required to facilitate system analysis and design. This report presents an analysis of the effects of a residual chirp on the IPR. As reference, there is a rich body of publications on various aspects of LFM chirps. A quick search reveals a plethora of articles, going back to the early 1950s. We mention here purely as trivia one of the earlier analysis papers on this waveform by Klauder, et al.

  4. Emotion Regulation and Impulsivity in Young Adults

    PubMed Central

    Schreiber, Liana R.N.; Grant, Jon E.; Odlaug, Brian L.

    2012-01-01

    Past research has linked both emotion regulation and impulsivity with the development and maintenance of addictions. However, no research has investigated the relationship between emotion regulation and impulsivity within young adults. In the present study, we analyzed 194 young adults (27.8% female; 21.3 ± 3.32 years old; 91.8% single; 85.1% Caucasian), grouping them as low, average, or high emotionally dysregulated, and compared self-reported impulsivity, impulsive behaviors (such as alcohol and substance use and gambling) and cognitive impulsivity. We hypothesized that those with high levels of emotion dysregulation would score higher on self-reported and cognitive impulsivity, and report more impulsive behaviors. Analysis indicated that compared to low, the high emotion dysregulation group scored significantly higher on two self-report measures of impulsivity, harm avoidance, and cognitive reasoning. No significant differences were found between groups in impulsive behaviors and cognitive impulsivity. Overall, this study highlights the relationship between emotion dysregulation and impulsivity, suggesting that emotion regulation may be an important factor to consider when assessing individuals at a higher risk for developing an addiction. PMID:22385661

  5. Preliminary investigation of the impulsive and neuroanatomical characteristics of compulsive sexual behavior

    PubMed Central

    Miner, Michael H.; Raymond, Nancy; Mueller, Bryon A.; Lloyd, Martin; Lim, Kelvin O.

    2009-01-01

    In recent years there has been increased attention in a clinical syndrome characterized by excessive sexual thoughts, sexual urges, and/or sexual behaviors that has many aspects in common with impulse control disorders. This study provides a preliminary examination of the impulsive aspects of this syndrome, Compulsive Sexual Behavior (CSB), as conceptualized by Coleman and colleagues. Sixteen male subjects, 8 CSB patients and 8 non-patient controls, completed psychometric measures of impulsivity and compulsive sexual behavior, a behavioral task designed to assess impulse control (go/no-go task), and underwent diffusion tensor imaging (DTI) procedures. The results indicated that CSB patients were significantly more impulsive; whether measured by psychometric testing or the go/no-go procedure than controls. The results also indicate that CSB patients showed significantly higher superior frontal region mean diffusivity (MD) than controls. A correlational analysis indicated significant associations between impulsivity measures and inferior frontal region fractional anisotrophy (FA) and MD, but no associations with superior frontal region measures. Similar analyses indicated a significant negative association between superior frontal lobe MD and the compulsive sexual behavior inventory. Thus, while CSB patients were more impulsive than controls, the DTI results were not consistent with impulse control disorders. PMID:19836930

  6. Experimental study on thermal characteristics of positive leader discharges using Mach-Zehnder interferometry

    NASA Astrophysics Data System (ADS)

    Zhou, X.; Zeng, R.; Zhuang, C.; Chen, S.

    2015-06-01

    Leader discharge is one of the main phases in long air gap breakdown, which is characterized by high temperature and high conductivity. It is of great importance to determine thermal characteristics of leader discharges. In this paper, a long-optical-path Mach-Zehnder interferometer was set up to measure the thermal parameters (thermal diameter, gas density, and gas temperature) of positive leader discharges in atmospheric air. IEC standard positive switching impulse voltages were applied to a near-one-meter point-plane air gap. Filamentary channels with high gas temperature and low density corresponding to leader discharges were observed as significant distortions in the interference fringe images. Typical diameters of the entire heated channel range from 1.5 mm to 3.5 mm with an average expansion velocity of 6.7 m/s. In contrast, typical diameters of the intensely heated region with a sharp gas density reduction range from 0.4 mm to 1.1 mm, about one third of the entire heated channel. The radial distribution of the gas density is calculated from the fringe displacements by performing an Abel inverse transform. The typical calculated gas density reduction in the center of a propagating leader channel is 80% to 90%, corresponding to a gas temperature of 1500 K to 3000 K based on the ideal gas law. Leaders tend to terminate if the central temperature is below 1500 K.

  7. Experimental study on thermal characteristics of positive leader discharges using Mach-Zehnder interferometry

    SciTech Connect

    Zhou, X. Zeng, R.; Zhuang, C.; Chen, S.

    2015-06-15

    Leader discharge is one of the main phases in long air gap breakdown, which is characterized by high temperature and high conductivity. It is of great importance to determine thermal characteristics of leader discharges. In this paper, a long-optical-path Mach-Zehnder interferometer was set up to measure the thermal parameters (thermal diameter, gas density, and gas temperature) of positive leader discharges in atmospheric air. IEC standard positive switching impulse voltages were applied to a near-one-meter point-plane air gap. Filamentary channels with high gas temperature and low density corresponding to leader discharges were observed as significant distortions in the interference fringe images. Typical diameters of the entire heated channel range from 1.5 mm to 3.5 mm with an average expansion velocity of 6.7 m/s. In contrast, typical diameters of the intensely heated region with a sharp gas density reduction range from 0.4 mm to 1.1 mm, about one third of the entire heated channel. The radial distribution of the gas density is calculated from the fringe displacements by performing an Abel inverse transform. The typical calculated gas density reduction in the center of a propagating leader channel is 80% to 90%, corresponding to a gas temperature of 1500 K to 3000 K based on the ideal gas law. Leaders tend to terminate if the central temperature is below 1500 K.

  8. Natural laminar-turbulent transition delay by dielectric barrier discharge

    NASA Astrophysics Data System (ADS)

    Ustinov, Maxim; Kogan, Mikhail; Litvinov, Vladimir; Uspensky, Alexander

    2011-12-01

    The use dielectric barrier discharge for the delay of laminar turbulent transition excited by natural flow disturbances in a quiet wind-tunnel was investigated experimentally. Optimal electrodes location and the operational regime of high-voltage impulse generator provided maximal downstream shift of transition location were found. It was demonstrated that the 10% increase of the laminar part of boundary layer can be obtained using barrier discharge with the cross-flow electrodes. This gives up to 20% friction drag reduction.

  9. Gastroesophageal reflux - discharge

    MedlinePlus

    Peptic esophagitis - discharge; Reflux esophagitis - discharge; GERD - discharge; Heartburn - chronic - discharge ... You have gastroesophageal reflux disease (GERD). This is a condition in which food or liquid travels backwards from the stomach to the esophagus ( ...

  10. Ventriculoperitoneal shunt - discharge

    MedlinePlus

    ... ventriculoperitoneal - discharge; VP shunt - discharge; Shunt revision - discharge; Hydrocephalus shunt placement - discharge ... Your child has hydrocephalus and needed a shunt placed to drain excess fluid and relieve pressure in the brain. This buildup of brain ...

  11. Refractive corneal surgery - discharge

    MedlinePlus

    Nearsightedness surgery - discharge; Refractive surgery - discharge; LASIK - discharge; PRK - discharge ... You had refractive corneal surgery to help improve your vision. This surgery uses a laser to reshape your cornea. It corrects mild-to-moderate nearsightedness, ...

  12. Impulsivity and Clinical Symptoms among Adolescents with Non-Suicidal Self-Injury with or without Attempted Suicide

    PubMed Central

    Dougherty, Donald M.; Mathias, Charles W.; Marsh-Richard, Dawn M.; Prevette, Kristen N.; Dawes, Michael A.; Hatzis, Erin S.; Palmes, Guy; Nouvion, Sylvain O.

    2011-01-01

    This study examined clinical characteristics and laboratory-measured impulsive behavior of adolescents engaging in either non-suicidal self-injury with (NSSI+SA; n = 25) or without (NSSI-Only; n = 31) suicide attempts. We hypothesized that adolescent with NSSI+SI would exhibit more severe clinical symptoms and higher levels of behavioral impulsivity compared to adolescents with NSSI-Only. Adolescents were recruited from an inpatient psychiatric hospital unit and the two groups were compared on demographic characteristics, psychopathology, self-reported clinical ratings, methods of non-suicidal self-injury, and two laboratory impulsivity measures. Primary evaluations were conducted during psychiatric hospitalization, and a subset of those tested during hospitalization was retested 4-6 weeks after discharge. During hospitalization, NSSI+SA patients reported worse depression, hopelessness, and impulsivity on standard clinical measures, and demonstrated elevated impulsivity on a reward-directed laboratory measure compared to NSSI-Only patients. In the preliminary follow-up analyses, depression, hopelessness, suicidal ideation, and laboratory impulsivity were improved for both groups, but the NSSI+SA group still exhibited significantly more depressive symptoms, hopelessness, and impulsivity than the NSSI-Only group. Risk assessments for adolescents with NSSI+SA should include consideration not only of the severity of clinical symptoms but of the current level impulsivity as well. PMID:19631392

  13. Optimization of valve opening process for the suppression of impulse exhaust noise

    NASA Astrophysics Data System (ADS)

    Li, Jingxiang; Zhao, Shengdun

    2017-02-01

    Impulse exhaust noise generated by the sudden impact of discharging flow of pneumatic systems has significant temporal characteristics including high sound pressure and rapid sound transient. The impulse noise exposures are more hazardous to hearing than the energy equivalent uniform noise exposures. This paper presents a novel approach to suppress the peak sound pressure as a major indicator of impulsiveness of the impulse exhaust noise by an optimization of the opening process of valve. Relationships between exhaust flow and impulse noise are described by thermodynamics and noise generating mechanism. Then an optimized approach by controlling the valve opening process is derived under a constraint of pre-setting exhaust time. A modified servo-direct-driven valve was designed and assembled in a typical pneumatic system for the verification experiments comparing with an original solenoid valve. Experimental results with groups of initial cylinder pressures and pre-setting exhaust times are shown to verify the effects of the proposed optimization. Some indicators of energy-equivalent and impulsiveness are introduced to discuss the effects of the noise suppressions. Relationship between noise reduction and exhaust time delay is also discussed.

  14. Efficiency Analysis of a High-Specific Impulse Hall Thruster

    NASA Technical Reports Server (NTRS)

    Jacobson, David (Technical Monitor); Hofer, Richard R.; Gallimore, Alec D.

    2004-01-01

    Performance and plasma measurements of the high-specific impulse NASA-173Mv2 Hall thruster were analyzed using a phenomenological performance model that accounts for a partially-ionized plasma containing multiply-charged ions. Between discharge voltages of 300 to 900 V, the results showed that although the net decrease of efficiency due to multiply-charged ions was only 1.5 to 3.0 percent, the effects of multiply-charged ions on the ion and electron currents could not be neglected. Between 300 to 900 V, the increase of the discharge current was attributed to the increasing fraction of multiply-charged ions, while the maximum deviation of the electron current from its average value was only +5/-14 percent. These findings revealed how efficient operation at high-specific impulse was enabled through the regulation of the electron current with the applied magnetic field. Between 300 to 900 V, the voltage utilization ranged from 89 to 97 percent, the mass utilization from 86 to 90 percent, and the current utilization from 77 to 81 percent. Therefore, the anode efficiency was largely determined by the current utilization. The electron Hall parameter was nearly constant with voltage, decreasing from an average of 210 at 300 V to an average of 160 between 400 to 900 V. These results confirmed our claim that efficient operation can be achieved only over a limited range of Hall parameters.

  15. The Nature of Impulsivity: Visual Exposure to Natural Environments Decreases Impulsive Decision-Making in a Delay Discounting Task

    PubMed Central

    Berry, Meredith S.; Sweeney, Mary M.; Morath, Justice; Odum, Amy L.; Jordan, Kerry E.

    2014-01-01

    The benefits of visual exposure to natural environments for human well-being in areas of stress reduction, mood improvement, and attention restoration are well documented, but the effects of natural environments on impulsive decision-making remain unknown. Impulsive decision-making in delay discounting offers generality, predictive validity, and insight into decision-making related to unhealthy behaviors. The present experiment evaluated differences in such decision-making in humans experiencing visual exposure to one of the following conditions: natural (e.g., mountains), built (e.g., buildings), or control (e.g., triangles) using a delay discounting task that required participants to choose between immediate and delayed hypothetical monetary outcomes. Participants viewed the images before and during the delay discounting task. Participants were less impulsive in the condition providing visual exposure to natural scenes compared to built and geometric scenes. Results suggest that exposure to natural environments results in decreased impulsive decision-making relative to built environments. PMID:24841421

  16. Impulsive behavior and nicotinic acetylcholine receptors.

    PubMed

    Ohmura, Yu; Tsutsui-Kimura, Iku; Yoshioka, Mitsuhiro

    2012-01-01

    Higher impulsivity is thought to be a risk factor for drug addiction, criminal involvement, and suicide. Excessive levels of impulsivity are often observed in several psychiatric disorders including attention-deficit/hyperactivity disorder and schizophrenia. Previous studies have demonstrated that nicotinic acetylcholine receptors (nAChRs) are involved in impulsive behavior. Here, we introduce recent advances in this field and describe the role of the following nAChR-related brain mechanisms in modulating impulsive behavior: dopamine release in the ventral striatum; α4β2 nAChRs in the infralimbic cortex, which is a ventral part of the medial prefrontal cortex (mPFC); and dopamine release in the mPFC. We also suggest several potential therapeutic drugs to address these mechanisms in impulsivity-related disorders and explore future directions to further elucidate the roles of central nAChRs in impulsive behavior.

  17. Impulsivity and sexual assault in college men.

    PubMed

    Mouilso, Emily R; Calhoun, Karen S; Rosenbloom, Thomas G

    2013-01-01

    Although impulsivity has been consistently linked to perpetration of sexual aggression, results lack clarity because they do not account for the substantial heterogeneity associated with the construct. The UPPS-P model (Lynam, Smith, Whiteside, & Cyders, 2006), which was proposed to clarify the multidimensional nature of impulsivity, has yet to be applied to sexual aggression. We measured UPPS-P Impulsivity in a sample of male college students who also self-reported on perpetration of sexual aggression. As predicted, impulsivity distinguished perpetrators from nonperpetrators. Perpetrators scored higher than non-perpetrators on Negative Urgency, Positive Urgency, and lack of Premeditation. Results suggest that the impulsivity traits most relevant to sexual aggression are the tendency to act impulsively when experiencing intense emotions (Positive and Negative Urgency) and lack of forethought and planning (lack of Premeditation).

  18. Role of secondary emission on discharge dynamics in an atmospheric pressure dielectric barrier discharge

    SciTech Connect

    Tay, W. H.; Kausik, S. S.; Yap, S. L.; Wong, C. S.

    2014-04-15

    The discharge dynamics in an atmospheric pressure dielectric barrier discharge (DBD) is studied in a DBD reactor consisting of a pair of stainless steel parallel plate electrodes. The DBD discharge has been generated by a 50 Hz ac high voltage power source. The high-speed intensified charge coupled device camera is used to capture the images of filaments occurring in the discharge gap. It is observed that frequent synchronous breakdown of micro discharges occurs across the discharge gap in the case of negative current pulse. The experimental results reveal that secondary emissions from the dielectric surface play a key role in the synchronous breakdown of plasma filaments.

  19. Impulsively started incompressible turbulent jet

    SciTech Connect

    Witze, P O

    1980-10-01

    Hot-film anemometer measurements are presented for the centerline velocity of a suddenly started jet of air. The tip penetration of the jet is shown to be proportional to the square-root of time. A theoretical model is developed that assumes the transient jet can be characterized as a spherical vortex interacting with a steady-state jet. The model demonstrates that the ratio of nozzle radius to jet velocity defines a time constant that uniquely characterizes the behavior and similarity of impulsively started incompressible turbulent jets.

  20. Modeling of impulsive propellant reorientation

    NASA Technical Reports Server (NTRS)

    Hochstein, John I.; Patag, Alfredo E.; Chato, David J.

    1988-01-01

    The impulsive propellant reorientation process is modeled using the (Energy Calculations for Liquid Propellants in a Space Environment (ECLIPSE) code. A brief description of the process and the computational model is presented. Code validation is documented via comparison to experimentally derived data for small scale tanks. Predictions of reorientation performance are presented for two tanks designed for use in flight experiments and for a proposed full scale OTV tank. A new dimensionless parameter is developed to correlate reorientation performance in geometrically similar tanks. Its success is demonstrated.

  1. Impaired Decisional Impulsivity in Pathological Videogamers

    PubMed Central

    Irvine, Michael A.; Worbe, Yulia; Bolton, Sorcha; Harrison, Neil A.; Bullmore, Edward T.; Voon, Valerie

    2013-01-01

    Background Pathological gaming is an emerging and poorly understood problem. Impulsivity is commonly impaired in disorders of behavioural and substance addiction, hence we sought to systematically investigate the different subtypes of decisional and motor impulsivity in a well-defined pathological gaming cohort. Methods Fifty-two pathological gaming subjects and age-, gender- and IQ-matched healthy volunteers were tested on decisional impulsivity (Information Sampling Task testing reflection impulsivity and delay discounting questionnaire testing impulsive choice), and motor impulsivity (Stop Signal Task testing motor response inhibition, and the premature responding task). We used stringent diagnostic criteria highlighting functional impairment. Results In the Information Sampling Task, pathological gaming participants sampled less evidence prior to making a decision and scored fewer points compared with healthy volunteers. Gaming severity was also negatively correlated with evidence gathered and positively correlated with sampling error and points acquired. In the delay discounting task, pathological gamers made more impulsive choices, preferring smaller immediate over larger delayed rewards. Pathological gamers made more premature responses related to comorbid nicotine use. Greater number of hours played also correlated with a Motivational Index. Greater frequency of role playing games was associated with impaired motor response inhibition and strategy games with faster Go reaction time. Conclusions We show that pathological gaming is associated with impaired decisional impulsivity with negative consequences in task performance. Decisional impulsivity may be a potential target in therapeutic management. PMID:24146789

  2. The annoyance of impulsive helicopter noise

    NASA Technical Reports Server (NTRS)

    Karamcheti, K.

    1981-01-01

    A total of 96 impulsive and non-impulsive sounds were rated for annoyance by 10 subjects. The signals had the same amplitude spectrum with a maximum frequency of 4.75 kHz. By changing the phase of the spectral components different levels of impulsivity were obtained. The signals had coefficients of impulsivity of 10,8, 7,9, and -0.2 respectively. Further, signals had intensity levels 89 and 95 dBA, pulse repetition rates 10 and 20 Hz, and half the signals had pink noise added at a level 12 dBA lower than the level of the sound. The significant results were: The four females and six male subjects rated the impulsive sounds respectively 3.7 dB less annoying and 2.6 dB more annoying than the non-impulsive sounds. Overall, impulsivity had no effect. The hish pulse repetition rate increased annoyance by 2.2 dB. Addition of pink noise increased annoyance of the non-impulsive sounds 1.2 dB, but decreased the annoyance of the impulsive sounds 0.5 dB.

  3. Impulsiveness without discounting: the ecological rationality hypothesis.

    PubMed Central

    Stephens, David W.; Kerr, Benjamin; Fernández-Juricic, Esteban

    2004-01-01

    Observed animal impulsiveness challenges ideas from foraging theory about the fitness value of food rewards, and may play a role in important behavioural phenomena such as cooperation and addiction. Behavioural ecologists usually invoke temporal discounting to explain the evolution of animal impulsiveness. According to the discounting hypothesis, delay reduces the fitness value of the delayed food. We develop an alternative model for the evolution of impulsiveness that does not require discounting. We show that impulsive or short-sighted rules can maximize long-term rates of food intake. The advantages of impulsive rules come from two sources. First, naturally occurring choices have a foreground-background structure that reduces the long-term cost of impulsiveness. Second, impulsive rules have a discrimination advantage because they tend to compare smaller quantities. Discounting contributes little to this result. Although we find that impulsive rules are optimal in a simple foreground-background choice situation in the absence of discounting, in contrast we do not find comparable impulsiveness in binary choice situations even when there is strong discounting. PMID:15590596

  4. Analysis of impulse signals with Hylaty ELF station

    NASA Astrophysics Data System (ADS)

    Kulak, A.; Mlynarczyk, J.; Ostrowski, M.; Kubisz, J.; Michalec, A.

    2012-04-01

    Lighting discharges generate electromagnetic field pulses that propagate in the Earth-ionosphere waveguide. The attenuation in the ELF range is so small that the pulses originating from strong atmospheric discharges can be observed even several thousand kilometers away from the individual discharge. The recorded waveform depends on the discharge process, the Earth-ionosphere waveguide properties on the source-receiver path, and the transfer function of the receiver. If the distance from the source is known, an inverse method can be used for reconstructing the current moment waveform and the charge moment of the discharge. In order to reconstruct the source parameters from the recorded signal a reliable model of the radio wave propagation in the Earth-ionosphere waveguide as well as practical signal processing techniques are necessary. We present two methods, both based on analytical formulas. The first method allows for fast calculation of the charge moment of relatively short atmospheric discharges. It is based on peak amplitude measurement of the recorded magnetic component of the ELF EM field and it takes into account the receiver characteristics. The second method, called "inverse channel method" allows reconstructing the complete current moment waveform of strong atmospheric discharges that exhibit the continuing current phase, such as Gigantic Jets and Sprites. The method makes it possible to fully remove from the observed waveform the distortions related to the receiver's impulse response as well as the influence of the Earth-ionosphere propagation channel. Our ELF station is equipped with two magnetic antennas for Bx and By components measurement in the 0.03 to 55 Hz frequency range. ELF Data recording is carried out since 1993, with continuous data acquisition since 2005. The station features low noise level and precise timing. It is battery powered and located in the sparsely populated area, far from major electric power lines, which results in high

  5. A multifactorial and integrative approach to impulsivity in neuropsychology: insights from the UPPS model of impulsivity.

    PubMed

    Rochat, Lucien; Billieux, Joël; Gagnon, Jean; Van der Linden, Martial

    2017-04-11

    Risky and excessive behaviors, such as aggressive and compulsive behaviors, are frequently described in patients with brain damage and have dramatic psychosocial consequences. Although there is strong evidence that impulsivity constitutes a key factor at play in these behaviors, the literature about impulsivity in neuropsychology is to date scarce. In addition, examining and understanding these problematic behaviors requires the assumption that impulsivity is a multidimensional construct. Consequently, this article aims at shedding light on frequent risky and excessive behaviors in patients with brain damage by focusing on a unified, comprehensive, and well-validated model, namely, the UPPS model of impulsivity. This model considers impulsivity as a multidimensional construct that includes four facets: urgency, (lack of) premeditation, (lack of) perseverance, and sensation seeking. Furthermore, we discuss the psychological mechanisms underlying the dimensions of impulsivity, as well as the laboratory tasks designed to assess each mechanism and their neural bases. We then present a scale specifically designed to assess these four dimensions of impulsivity in patients with brain damage and examine the data regarding this multidimensional approach to impulsivity in neuropsychology. This review supports the need to adopt a multifactorial and integrative approach toward impulsive behaviors, and the model presented provides a valuable rationale to disentangle the nature of brain systems and mechanisms underlying impulsive behaviors in patients with brain damage. It may also foster further relevant research in the field of impulsivity and improve assessment and rehabilitation of impulsive behaviors in clinical settings.

  6. Impulsivity and the Sexes: Measurement and Structural Invariance of the UPPS-P Impulsive Behavior Scale

    ERIC Educational Resources Information Center

    Cyders, Melissa A.

    2013-01-01

    Before it is possible to test whether men and women differ in impulsivity, it is necessary to evaluate whether impulsivity measures are invariant across sex. The UPPS-P Impulsive Behavior Scale (negative urgency, lack of premeditation, lack of perseverance, and sensation seeking, with added subscale of positive urgency) is one measure of five…

  7. A negative relationship between ventral striatal loss anticipation response and impulsivity in borderline personality disorder.

    PubMed

    Herbort, Maike C; Soch, Joram; Wüstenberg, Torsten; Krauel, Kerstin; Pujara, Maia; Koenigs, Michael; Gallinat, Jürgen; Walter, Henrik; Roepke, Stefan; Schott, Björn H

    2016-01-01

    Patients with borderline personality disorder (BPD) frequently exhibit impulsive behavior, and self-reported impulsivity is typically higher in BPD patients when compared to healthy controls. Previous functional neuroimaging studies have suggested a link between impulsivity, the ventral striatal response to reward anticipation, and prediction errors. Here we investigated the striatal neural response to monetary gain and loss anticipation and their relationship with impulsivity in 21 female BPD patients and 23 age-matched female healthy controls using functional magnetic resonance imaging (fMRI). Participants performed a delayed monetary incentive task in which three categories of objects predicted a potential gain, loss, or neutral outcome. Impulsivity was assessed using the Barratt Impulsiveness Scale (BIS-11). Compared to healthy controls, BPD patients exhibited significantly reduced fMRI responses of the ventral striatum/nucleus accumbens (VS/NAcc) to both reward-predicting and loss-predicting cues. BIS-11 scores showed a significant positive correlation with the VS/NAcc reward anticipation responses in healthy controls, and this correlation, while also nominally positive, failed to reach significance in BPD patients. BPD patients, on the other hand, exhibited a significantly negative correlation between ventral striatal loss anticipation responses and BIS-11 scores, whereas this correlation was significantly positive in healthy controls. Our results suggest that patients with BPD show attenuated anticipation responses in the VS/NAcc and, furthermore, that higher impulsivity in BPD patients might be related to impaired prediction of aversive outcomes.

  8. Self-reported impulsivity is negatively correlated with amygdalar volumes in cocaine dependence

    PubMed Central

    Mei, Songli; Xu, Jiansong; Carroll, Kathleen M.; Potenza, Marc N.

    2015-01-01

    Although impulsivity has been associated with cocaine dependence and other addictive behaviors, the biological factors underlying impulsivity have yet to be precisely determined. This study aimed to examine relationships between impulsivity and volumes of the amygdala and hippocampus in cocaine-dependent and healthy comparison individuals. The Barratt Impulsiveness Scale (BIS-11) was used to assess impulsivity. FreeSurfer was used to assess amygdalar and hippocampal volumes from high-resolution structural magnetic resonance images. Relative to healthy comparison subjects, cocaine-dependent individuals scored higher on all three subscales of BIS-11 but did not differ from healthy comparison subjects in amygdalar or hippocampal volumes. Cocaine-dependent individuals showed significant negative correlations between amygdalar volumes and scores on the BIS-11 Attentional subscale, and this relationship differed significantly from the non-significant relationship in healthy comparison subjects. As individual differences in amygdalar structure may contribute to the high impulsivity observed in cocaine-dependent individuals, the findings suggest that future studies should assess the extent to which therapies that target impulsivity in cocaine dependence may operate through the amygdala or alter its structure or function. PMID:26187551

  9. Effect of management of patients with Anorexia and Bulimia nervosa on symptoms and impulsive behavior.

    PubMed

    Sernec, Karin; Tomori, Martina; Zalar, Bojan

    2010-12-01

    The aim of the study was to provide further and up to date information on the evaluation of the management of Anorexia and Bulimia nervosa at the Eating Disorders Unit (EDU) of the Ljubljana Psychiatric Clinic, based upon detailed assessment of the eating disorders specific and non specific symptoms of impulsive behaviors, highly correlated with these entities. 34 female patients with anorexia (restrictive or purgative type) and 38 female patients with Bulimia nervosa (purgative or non-purgative type) undergoing hospital treatment at the EDU were evaluated upon admission, as well as upon discharge and three and six months after discharge, using the Eating Disorder Questionnaire. Upon discharge a marked decrease in the overall symptoms was noted. The differences in symptoms incidences between the two groups were significantly specific for the individual form of eating disorder, especially upon admission, and were more pronounced in anorexia group. In later measurements, performed during the period of three and six months after discharge, a mild trend of increase in the disorder specific symptoms was detected in both groups, but was not statistically significant. In addition to binging on food, striking, quarreling and spending sprees are characteristics of patients with eating disorders, which in particular apply to the Bulimia nervosa group. Apart from the disorder specific symptoms, impulsive behavior was also reduced during study period, while the difference in its occurrence between the two groups gradually became non-significant. The management of patients with eating disorders at the EDU was successful in both groups, confirmed by an intense reduction of the disorder specific symptoms, impulsive behavior and increased stability recorded three and six months after discharge. The study strongly suggests that the effect of treatment regime for eating disorders can be predicted by careful assessment of the relevant symptoms and impulsive behavioral patterns.

  10. Impulsive model for reactive collisions

    NASA Technical Reports Server (NTRS)

    Marron, M. T.; Bernstein, R. B.

    1972-01-01

    A simple classical mechanical model of the reactive scattering of a structureless atom A and a quasi-diatomic BC is developed which takes full advantage of energy, linear and angular momentum conservation relations but introduces a minimum of further assumptions. These are as follows: (1) the vibrational degree of freedom of the reactant (BC) and product (AB) molecules is suppressed, so the change in vibrational energy is simply a parameter; (2) straight-line trajectories are assumed outside of a reaction shell; (3) within this zone, momentum transfer occurs impulsively (essentially instantaneously) following mass transfer; (4) the impulse, which may be either positive or negative, is directed along the BC axis, which may, however, assume all orientations with respect to the incident relative velocity. The model yields differential and total cross sections and product rotational energy distributions for a given collision exoergicity Q, or for any known distribution over Q. Numerical results are presented for several prototype reactions whose dynamics have been well-studied.

  11. Imaging of spatial distributions of the millimeter wave intensity by using visible continuum radiation from a discharge in a Cs–Xe mixture. Part I: Review of the method and its fundamentals

    NASA Astrophysics Data System (ADS)

    Gitlin, M. S.

    2017-02-01

    The first part of the review is presented which is dedicated to the time-resolved method of imaging and measuring the spatial distribution of the intensity of millimeter waves by using visible continuum (VC) emitted by the positive column (PC) of a dc discharge in a mixture of cesium vapor with xenon. The review focuses on the operating principles, fundamentals, and applications of this new technique. The design of the discharge tube and experimental setup used to create a wide homogeneous plasma slab with the help of the Cs-Xe discharge at a gas pressure of 45 Torr are described. The millimeter-wave effects on the plasma slab are studied experimentally. The mechanism of microwave-induced variations in the VC brightness and the causes of violation of the local relation between the VC brightness and the intensity of millimeter waves are discussed. Experiments on the imaging of the field patterns of horn antennas and quasi-optical beams demonstrate that this technique can be used for good-quality imaging of millimeter-wave beams in the entire millimeter-wavelength band. The method has a microsecond temporal resolution and a spatial resolution of about 2 mm. Energy sensitivities of about 10 μJ/cm2 in the Ka-band and about 200 μJ/cm2 in the D-band have been demonstrated.

  12. Reliability and Validity of Measures of Impulsive Choice and Impulsive Action in Smokers Trying to Quit

    PubMed Central

    McCarthy, Danielle E.; Bold, Krysten W.; Minami, Haruka; Yeh, Vivian M.; Rutten, Emily; Nadkarni, Shruti G.; Chapman, Gretchen B.

    2016-01-01

    Cross-sectional research suggests that smokers are more impulsive than are non-smokers, but few studies have examined relations between impulsiveness and later success in quitting smoking. The purpose of this study was to investigate the reliability and predictive validity of facets of impulsiveness in adult smokers trying to quit. Baseline behavioral measures of impulsive choice (assessed with a delay discounting task) and impulsive action (assessed with a measure of behavioral disinhibition) were used as predictors of smoking cessation success over 12 weeks. The sample included 116 adult (18 years old or older) daily smokers from central New Jersey. Impulsive choice, impulsive action, and self-reported impulsiveness were not significantly related to one another at baseline. Impulsive choice had high test-retest reliability from pre- to post-quit, whereas impulsive action was less stable. Test-retest reliability from pre-quit to three weeks post-quit was moderated by achievement of seven-day abstinence. Baseline impulsive action was significantly negatively related to quitting for at least one day in the first two weeks of a quit attempt and of prolonged abstinence (no relapse over the next 10 weeks). Baseline impulsive choice was robustly associated with biochemically verified seven-day point-prevalence abstinence 12 weeks post-quit, such that those with lower delay discounting were more likely to achieve abstinence. Facets of impulsiveness appear to function largely independently in adult smokers, as indicated by their lack of inter-correlation, differential stability, and differential relations with abstinence. Impulsive action may impede initial quitting, whereas impulsive choice may be an obstacle to maintaining lasting abstinence. PMID:26751623

  13. Impulse generated during unsteady maneuvering of swimming fish

    NASA Astrophysics Data System (ADS)

    Epps, Brenden P.; Techet, Alexandra H.

    2007-11-01

    The relationship between the maneuvering kinematics of a Giant Danio ( Danio aequipinnatus) and the resulting vortical wake is investigated for a rapid, ‘C’-start maneuver using fully time-resolved (500 Hz) particle image velocimetry (PIV). PIV illuminates the two distinct vortices formed during the turn. The fish body rotation is facilitated by the initial, or “maneuvering” vortex formation, and the final fish velocity is augmented by the strength of the second, “propulsive” vortex. Results confirm that the axisymmetric vortex ring model is reasonable to use in calculating the hydrodynamic impulse acting on the fish. The total linear momentum change of the fish from its initial swimming trajectory to its final swimming trajectory is balanced by the vector sum of the impulses of both vortex rings. The timing of vortex formation is uniquely synchronized with the fish motion, and the choreography of the maneuver is addressed in the context of the resulting hydrodynamic forces.

  14. Impulse generated during unsteady maneuvering of swimming fish

    NASA Astrophysics Data System (ADS)

    Epps, Brenden P.; Techet, Alexandra H.

    The relationship between the maneuvering kinematics of a Giant Danio (Danio aequipinnatus) and the resulting vortical wake is investigated for a rapid, 'C'-start maneuver using fully time-resolved (500 Hz) particle image velocimetry (PIV). PIV illuminates the two distinct vortices formed during the turn. The fish body rotation is facilitated by the initial, or "maneuvering" vortex formation, and the final fish velocity is augmented by the strength of the second, "propulsive" vortex. Results confirm that the axisymmetric vortex ring model is reasonable to use in calculating the hydrodynamic impulse acting on the fish. The total linear momentum change of the fish from its initial swimming trajectory to its final swimming trajectory is balanced by the vector sum of the impulses of both vortex rings. The timing of vortex formation is uniquely synchronized with the fish motion, and the choreography of the maneuver is addressed in the context of the resulting hydrodynamic forces.

  15. Temporal Preparation, Response Inhibition and Impulsivity

    ERIC Educational Resources Information Center

    Correa, Angel; Trivino, Monica; Perez-Duenas, Carolina; Acosta, Alberto; Lupianez, Juan

    2010-01-01

    Temporal preparation and impulsivity involve overlapping neural structures (prefrontal cortex) and cognitive functions (response inhibition and time perception), however, their interrelations had not been investigated. We studied such interrelations by comparing the performance of groups with low vs. high non-clinical trait impulsivity during a…

  16. Hyperkinetic Impulse Disorder in Children's Behavior Problems

    ERIC Educational Resources Information Center

    Laufer, Maurice W.; Denhoff, Eric; Solomons, Gerald

    2011-01-01

    A very common cause of children's behavior disorder disturbance is an entity described as the hyperkinetic impulse disorder. This is characterized by hyperactivity, short attention span and poor powers of concentration, irritability, impulsiveness, variability, and poor schoolwork. The existence of this complexity may lead to many psychological…

  17. Assessing impulsivity changes in Alzheimer disease.

    PubMed

    Rochat, Lucien; Delbeuck, Xavier; Billieux, Joël; d'Acremont, Mathieu; Van der Linden, Anne-Claude Juillerat; Van der Linden, Martial

    2008-01-01

    Impulsive behaviors are common in brain-damaged patients including those with neurodegenerative diseases such as Alzheimer disease (AD). The objective of this study was to develop and validate a short version of the UPPS Impulsive Behavior Scale assessing changes on 4 different dimensions of impulsivity, namely urgency, (lack of) premeditation, (lack of) perseverance, and sensation seeking, arising in the course of a neurodegenerative disease. To this end, caregivers of 83 probable AD patients completed a short questionnaire adapted from the UPPS Impulsive Behavior Scale. Exploratory and confirmatory factor analyses of the data were performed and revealed that a model with 4 distinct but related latent variables corresponding to 4 different dimensions of impulsivity fit the data best. Furthermore, the results showed that lack of perseverance, followed by lack of premeditation and urgency, increased after the onset of the disease, whereas sensation seeking decreased. Overall, the multifaceted nature of impulsivity was confirmed in a sample of AD patients, whose caregivers reported significant changes regarding each facet of impulsivity. Consequently, the short version of the UPPS Impulsive Behavior Scale opens up interesting prospects for a better comprehension of behavioral symptoms of dementia.

  18. Impulsive Vaccination for an Epidemiology Model

    NASA Astrophysics Data System (ADS)

    De la Sen, M.; Garrido, A. J.

    2017-03-01

    This paper investigates sufficient conditions of almost periodic sand periodic solutions of an integral model under impulsive controls. Since the model is of generic epidemiological interest, such impulsive controls are either vaccination actions or abrupt variations of the infected population due to infected immigration or lost of infective numbers due to either vaccination or lost of infected population by out-migration.

  19. Impulsivity, School Context, and School Misconduct

    ERIC Educational Resources Information Center

    Vogel, Matt; Barton, Michael S.

    2013-01-01

    Impulsivity holds a central place in the explanations of adolescent delinquency. Recent research suggests that neighborhood characteristics, particularly SES (socioeconomic status), perceived supervision, and collective efficacy, moderate the association between impulsivity and delinquency. However, findings to date have been equivocal, and the…

  20. Solar Impulse's Solar-Powered Plane

    ScienceCinema

    Moniz, Ernest; Piccard, Bertrand; Reicher, Dan

    2016-07-12

    Solar Impulse lands in Washington, DC at Washington Dulles International Airport as part of its journey across the United States. Secretary Ernest Moniz speaks about how advancements like those at the Department of Energy are leading the way for innovations like the solar-powered plane. Footage of the solar-powered plane courtesy of Solar Impulse.

  1. Solar Impulse's Solar-Powered Plane

    SciTech Connect

    Moniz, Ernest; Piccard, Bertrand; Reicher, Dan

    2013-07-08

    Solar Impulse lands in Washington, DC at Washington Dulles International Airport as part of its journey across the United States. Secretary Ernest Moniz speaks about how advancements like those at the Department of Energy are leading the way for innovations like the solar-powered plane. Footage of the solar-powered plane courtesy of Solar Impulse.

  2. Effects of Cannabis on Impulsivity: A Systematic Review of Neuroimaging Findings

    PubMed Central

    Wrege, Johannes; Schmidt, André; Walter, Anna; Smieskova, Renata; Bendfeldt, Kerstin; Radue, Ernst-Wilhelm; Lang, Undine E.; Borgwardt, Stefan

    2014-01-01

    We conducted a systematic review to assess the evidence for specific effects of cannabis on impulsivity, disinhibition and motor control. The review had a specific focus on neuroimaging findings associated with acute and chronic use of the drug and covers literature published up until May 2012. Seventeen studies were identified, of which 13 met the inclusion criteria; three studies investigated acute effects of cannabis (1 fMRI, 2 PET), while six studies investigated non-acute functional effects (4 fMRI, 2 PET), and four studies investigated structural alterations. Functional imaging studies of impulsivity studies suggest that prefrontal blood flow is lower in chronic cannabis users than in controls. Studies of acute administration of THC or marijuana report increased brain metabolism in several brain regions during impulsivity tasks. Structural imaging studies of cannabis users found differences in reduced prefrontal volumes and white matter integrity that might mediate the abnormal impulsivity and mood observed in marijuana users. To address the question whether impulsivity as a trait precedes cannabis consumption or whether cannabis aggravates impulsivity and discontinuation of usage more longitudinal study designs are warranted. PMID:23829358

  3. Effects of cannabis on impulsivity: a systematic review of neuroimaging findings.

    PubMed

    Wrege, Johannes; Schmidt, Andre; Walter, Anna; Smieskova, Renata; Bendfeldt, Kerstin; Radue, Ernst-Wilhelm; Lang, Undine E; Borgwardt, Stefan

    2014-01-01

    We conducted a systematic review to assess the evidence for specific effects of cannabis on impulsivity, disinhibition and motor control. The review had a specific focus on neuroimaging findings associated with acute and chronic use of the drug and covers literature published up until May 2012. Seventeen studies were identified, of which 13 met the inclusion criteria; three studies investigated acute effects of cannabis (1 fMRI, 2 PET), while six studies investigated non-acute functional effects (4 fMRI, 2 PET), and four studies investigated structural alterations. Functional imaging studies of impulsivity studies suggest that prefrontal blood flow is lower in chronic cannabis users than in controls. Studies of acute administration of THC or marijuana report increased brain metabolism in several brain regions during impulsivity tasks. Structural imaging studies of cannabis users found differences in reduced prefrontal volumes and white matter integrity that might mediate the abnormal impulsivity and mood observed in marijuana users. To address the question whether impulsivity as a trait precedes cannabis consumption or whether cannabis aggravates impulsivity and discontinuation of usage more longitudinal study designs are warranted.

  4. Brain functional connectivity changes in children that differ in impulsivity temperamental trait

    PubMed Central

    Inuggi, Alberto; Sanz-Arigita, Ernesto; González-Salinas, Carmen; Valero-García, Ana V.; García-Santos, Jose M.; Fuentes, Luis J.

    2014-01-01

    Impulsivity is a core personality trait forming part of normal behavior and contributing to adaptive functioning. However, in typically developing children, altered patterns of impulsivity constitute a risk factor for the development of behavioral problems. Since both pathological and non-pathological states are commonly characterized by continuous transitions, we used a correlative approach to investigate the potential link between personality and brain dynamics. We related brain functional connectivity of typically developing children, measured with magnetic resonance imaging at rest, with their impulsivity scores obtained from a questionnaire completed by their parents. We first looked for areas within the default mode network (DMN) whose functional connectivity might be modulated by trait impulsivity. Then, we calculated the functional connectivity among these regions and the rest of the brain in order to assess if impulsivity trait altered their relationships. We found two DMN clusters located at the posterior cingulate cortex and the right angular gyrus which were negatively correlated with impulsivity scores. The whole-brain correlation analysis revealed the classic network of correlating and anti-correlating areas with respect to the DMN. The impulsivity trait modulated such pattern showing that the canonical anti-phasic relation between DMN and action-related network was reduced in high impulsive children. These results represent the first evidence that the impulsivity, measured as personality trait assessed through parents' report, exerts a modulatory influence over the functional connectivity of resting state brain networks in typically developing children. The present study goes further to connect developmental approaches, mainly based on data collected through the use of questionnaires, and behavioral neuroscience, interested in how differences in brain structure and functions reflect in differences in behavior. PMID:24834038

  5. Brain functional connectivity changes in children that differ in impulsivity temperamental trait.

    PubMed

    Inuggi, Alberto; Sanz-Arigita, Ernesto; González-Salinas, Carmen; Valero-García, Ana V; García-Santos, Jose M; Fuentes, Luis J

    2014-01-01

    Impulsivity is a core personality trait forming part of normal behavior and contributing to adaptive functioning. However, in typically developing children, altered patterns of impulsivity constitute a risk factor for the development of behavioral problems. Since both pathological and non-pathological states are commonly characterized by continuous transitions, we used a correlative approach to investigate the potential link between personality and brain dynamics. We related brain functional connectivity of typically developing children, measured with magnetic resonance imaging at rest, with their impulsivity scores obtained from a questionnaire completed by their parents. We first looked for areas within the default mode network (DMN) whose functional connectivity might be modulated by trait impulsivity. Then, we calculated the functional connectivity among these regions and the rest of the brain in order to assess if impulsivity trait altered their relationships. We found two DMN clusters located at the posterior cingulate cortex and the right angular gyrus which were negatively correlated with impulsivity scores. The whole-brain correlation analysis revealed the classic network of correlating and anti-correlating areas with respect to the DMN. The impulsivity trait modulated such pattern showing that the canonical anti-phasic relation between DMN and action-related network was reduced in high impulsive children. These results represent the first evidence that the impulsivity, measured as personality trait assessed through parents' report, exerts a modulatory influence over the functional connectivity of resting state brain networks in typically developing children. The present study goes further to connect developmental approaches, mainly based on data collected through the use of questionnaires, and behavioral neuroscience, interested in how differences in brain structure and functions reflect in differences in behavior.

  6. Multidimensionality in Impulsivity and Alcohol Use: A Meta-Analysis using the UPPS Model of Impulsivity

    PubMed Central

    Coskunpinar, Ayca; Dir, Allyson L.; Cyders, Melissa A.

    2013-01-01

    Background Although there is considerable support for the relationship between impulsivity and alcohol use, the use of multidimensional conceptualizations of impulsivity and alcohol use has lead to varying relationship sizes across studies. The aims of the current meta-analysis are to (1) examine variability in the magnitude of the bivariate relationship between impulsivity and alcohol use across studies, and (2) describe the pattern of effects between specific impulsivity traits and alcohol use variables, using the UPPS Model of Impulsivity. Methods Ninety-six studies were meta-analyzed using a random effects model to examine the relationship between general impulsivity and alcohol use, as well as the relationships among separate impulsivity traits based in the UPPS model of impulsivity and specific alcohol use outcomes. Results Results indicate that, in general, impulsivity and alcohol use are related (r = .28); however, this effect size varied significantly across studies (from −.05 to 1.02). Drinking quantity was most strongly predicted by lack of perseverance (r = .32), whereas all traits equally predicted drinking frequency. Drinking problems were most highly related to negative (r = .35) and positive (r = .34) urgency, and alcohol dependence was most highly related to negative urgency (r = .38) and lack of planning (r = .37). Conclusion Effect sizes between impulsivity and alcohol use vary significantly by UPPS trait used in each study; thus, findings suggest and further reinforce the view in the literature that specific impulsivity-related constructs differentially relate to specific alcohol use outcomes. PMID:23578176

  7. Impulse position control algorithms for nonlinear systems

    NASA Astrophysics Data System (ADS)

    Sesekin, A. N.; Nepp, A. N.

    2015-11-01

    The article is devoted to the formalization and description of impulse-sliding regime in nonlinear dynamical systems that arise in the application of impulse position controls of a special kind. The concept of trajectory impulse-sliding regime formalized as some limiting network element Euler polygons generated by a discrete approximation of the impulse position control This paper differs from the previously published papers in that it uses a definition of solutions of systems with impulse controls, it based on the closure of the set of smooth solutions in the space of functions of bounded variation. The need for the study of such regimes is the fact that they often arise when parry disturbances acting on technical or economic control system.

  8. Impulse position control algorithms for nonlinear systems

    SciTech Connect

    Sesekin, A. N.; Nepp, A. N.

    2015-11-30

    The article is devoted to the formalization and description of impulse-sliding regime in nonlinear dynamical systems that arise in the application of impulse position controls of a special kind. The concept of trajectory impulse-sliding regime formalized as some limiting network element Euler polygons generated by a discrete approximation of the impulse position control This paper differs from the previously published papers in that it uses a definition of solutions of systems with impulse controls, it based on the closure of the set of smooth solutions in the space of functions of bounded variation. The need for the study of such regimes is the fact that they often arise when parry disturbances acting on technical or economic control system.

  9. Modified impulsive synchronization of hyperchaotic systems

    NASA Astrophysics Data System (ADS)

    Haeri, Mohammad; Dehghani, Mahsa

    2010-03-01

    In an original impulsive synchronization only instantaneous errors are used to determine the impulsive inputs. To improve the synchronization performance, addition of an integral term of the errors is proposed here. In comparison with the original form, the proposed modification increases the impulse distances which leads to reduction in the control cost as the most important characteristic of the impulsive synchronization technique. It can also decrease the error magnitude in the presence of noise. Sufficient conditions are presented through four theorems for different situations (nominal, uncertain, noisy, and noisy uncertain cases) under which stability of the error dynamics is guaranteed. Results from computer based simulations are provided to illustrate feasibility and effectiveness of the modified impulsive synchronization method applied on Rossler hyperchaotic systems.

  10. Helicopter impulsive noise: Theoretical and experimental status

    NASA Technical Reports Server (NTRS)

    Schmitz, F. H.; Yu, Y. H.

    1983-01-01

    The theoretical and experimental status of helicopter impulsive noise is reviewed. The two major source mechanisms of helicopter impulsive noise are addressed: high-speed impulsive noise and blade-vortex interaction impulsive noise. A thorough physical explanation of both generating mechanism is presented together with model and full-scale measurements of the phenomena. Current theoretical prediction methods are compared with experimental findings of isolated rotor tests. The noise generating mechanism of high speed impulsive noise are fairly well understood - theory and experiment compare nicely over Mach number ranges typical of today's helicopters. For the case of blade-vortex interaction noise, understanding of noise generating mechanisms and theoretical comparison with experiment are less satisfactory. Several methods for improving theory-experiment are suggested.

  11. The horizontal computerized rotational impulse test.

    PubMed

    Furman, Joseph M; Shirey, Ian; Roxberg, Jillyn; Kiderman, Alexander

    2016-01-01

    Whole-body impulsive rotations were used to overcome several limitations associated with manual head impulse testing. A computer-controlled rotational chair delivered brief, whole-body, earth-vertical axis yaw impulsive rotations while eye movements were measured using video-oculography. Results from an unselected group of 20 patients with dizziness and a group of 22 control subjects indicated that the horizontal computerized rotational head impulse test (crHIT) is well-tolerated and provides an estimate of unidirectional vestibulo-ocular reflex gain comparable to results from caloric testing. This study demonstrates that the horizontal crHIT is a new assessment tool that overcomes many of the limitations of manual head impulse testing and provides a reliable laboratory-based measure of unilateral horizontal semicircular canal function.

  12. Successful restrained eating and trait impulsiveness.

    PubMed

    van Koningsbruggen, Guido M; Stroebe, Wolfgang; Aarts, Henk

    2013-01-01

    Restrained eaters with high scores on the Perceived Self-Regulatory Success in Dieting Scale (PSRS) are more successful than low scorers in regulating their food intake. According to the theory of temptation-elicited goal activation (Fishbach, Friedman, & Kruglanski, 2003), they have become successful because, due to earlier repeated instances of successful self-control, they formed an associative link between temptations and thoughts of dieting. It is unclear, however, why they should have been more successful in earlier attempts at self-control than their unsuccessful counterparts. We examined whether trait impulsiveness plays a role by investigating the associations between dietary restraint, trait impulsiveness, and PSRS. Results showed that the interaction between dietary restraint and impulsiveness predicted dieting success: A lower level of impulsiveness was associated with greater dieting success among restrained eaters. These results suggest that restrained eaters who are less impulsive are more likely to become successful restrained eaters as identified with the PSRS.

  13. Tennis elbow surgery - discharge

    MedlinePlus

    ... epicondylitis surgery - discharge; Lateral tendinosis surgery - discharge; Lateral tennis elbow surgery - discharge ... long as you are told. This helps ensure tennis elbow will not return. You may be prescribed a ...

  14. Eye muscle repair - discharge

    MedlinePlus

    ... Lazy eye repair - discharge; Strabismus repair - discharge; Extraocular muscle surgery - discharge ... You or your child had eye muscle repair surgery to correct eye muscle ... term for crossed eyes is strabismus. Children most often ...

  15. Asthma - child - discharge

    MedlinePlus

    Pediatric asthma - discharge; Wheezing - discharge; Reactive airway disease - discharge ... Your child has asthma , which causes the airways of the lungs to swell and narrow. In the hospital, the doctors and nurses helped ...

  16. Gastric bypass surgery - discharge

    MedlinePlus

    Bariatric surgery - gastric bypass - discharge; Roux-en-Y gastric bypass - discharge; Gastric bypass - Roux-en-Y - discharge; Obesity ... Gloy VL, Briel M, Bhatt DL, et al. Bariatric surgery versus non-surgical treatment for obesity: a systematic ...

  17. Conversion of Impulse Voltage Generator Into Steep Wave Impulse Test-Equipment

    NASA Astrophysics Data System (ADS)

    Khan, Mohammed Zaid; Tanwar, Surender Singh; Dayama, Ravindra; Choudhary, Rahul Raj; Mangal, Ravindra

    This paper demonstrates the alternative measures to generate the Steep wave impulse by using Impulse Voltage Generator (IVG) for high voltage testing of porcelain insulators. The modification of IVG by incorporating compensation of resistor, inductor, and capacitor has been achieved and further performance of the modified system has been analyzed by applying the generated lightning impulse and analyzing the electrical characteristics of impulse waves under standard lightning and fast rise multiple lightning waveform to determine the effect to improve rise time. The advantageous results have been received and being reported such as increase in overshoot compensation, increase in capacitive and inductive load ranges. Such further reduces the duration of oscillations of standard impulse voltages. The reduction in oscillation duration of steep front impulse voltages may be utilized in up gradation of Impulse Voltage Generator System. Stray capacitance could further be added in order to get the minimized difference of measurement between simulation and the field establishment.

  18. Prostate brachytherapy - discharge

    MedlinePlus

    Implant therapy - prostate cancer - discharge; Radioactive seed placement - discharge ... You had a procedure called brachytherapy to treat prostate cancer. Your treatment lasted 30 minutes or more, depending ...

  19. ACL reconstruction - discharge

    MedlinePlus

    Anterior cruciate ligament reconstruction - discharge; ACL reconstruction - discharge ... had surgery to reconstruct your anterior cruciate ligament (ACL). The surgeon drilled holes in the bones of ...

  20. Identifying Groundwater Discharge Sources and Associated Geochemical Influences Using Resistivity Imaging and Geochemical Tracers in a Semi-Arid Estuary in South Texas

    NASA Astrophysics Data System (ADS)

    Douglas, A. R.; Murgulet, D.; Spalt, N.

    2015-12-01

    The Nueces Bay (NB) system has been found to be ecologically unsound due to the loss/alteration of habitat and flow regimes required by indicator species and compromised nutrient cycling and sediment loading. The management practices of freshwater inflow regimes to NB concentrates on surface water flows and does not account for groundwater inflows, though submarine groundwater discharge (SGD) has been identified as a source of freshwater and limiting nutrients that could significantly impact bay salinities and nutrient loading. To encompass the range of spatio-temporal variabilities occurring between groundwater (GW) and surface-water (SW), multiple methods, including resistivity imaging, geochemical tracers, and radioisotopes, are applied in conjunction to identify SGD sources. Preliminary continuous resistivity profile surveys identified multiple possible GW upwelling paths from which thirteen stations were chosen in NB and two stations in Nueces River (NR). A Principal Component Analysis (PCA) of initial geochemical, nutrient and radioisotope data, shows that 76% of the variation in the data is explained by three factors: seasonality, freshwater inflows, and reducing environment. Significant seasonal variation is seen in average SW salinity (37psu in September 2014 to 4psu in June 2015), Ra-224 (359dpm/L in September to 636dpm/L in December), Ra-226 (268dpm/L in September to 570 dpm/L in December), ammonium (1.3μM in September to 5.5μM in April), and chlorophyll-α (3.99μg/L in December to 12.3 μg/L in April). Additionally, short-lived radioisotopes Rn-222 and Ra-224 are consistently elevated near the NR mouth, the inflow from Gum Hollow Creek, and a single station in the middle of the Bay indicating more localized, active SGD sources. However, only the stations in NR and at the NR mouth show consistently strong correlations to chlorophyll-α, phosphate, and silicate, with the river station closest to NB having the highest concentrations of nitrogen

  1. Ground state atomic oxygen in high-power impulse magnetron sputtering: a quantitative study

    NASA Astrophysics Data System (ADS)

    Britun, Nikolay; Belosludtsev, Alexandr; Silva, Tiago; Snyders, Rony

    2017-02-01

    The ground state density of oxygen atoms in reactive high-power impulse magnetron sputtering discharges has been studied quantitatively. Both time-resolved and space-resolved measurements were conducted. The measurements were performed using two-photon absorption laser-induced fluorescence (TALIF), and calibrated by optical emission actinometry with multiple Ar emission lines. The results clarify the dynamics of the O ground state atoms in the discharge afterglow significantly, including their propagation and fast decay after the plasma pulse, as well as the influence of gas pressure, O2 admixture, etc.

  2. Characteristics of corona impulses from insulated wires subjected to high ac voltages

    NASA Technical Reports Server (NTRS)

    Doreswamy, C. V.; Crowell, C. S.

    1976-01-01

    Corona discharges arise due to ionization of air or gas subject to high electric fields. The free electrons and ions contained in these discharges interact with molecules of insulating materials, resulting in chemical changes and destroying the electrical insulating properties. The paper describes some results of measurements aimed at determining corona pulse waveforms, their repetition rate, and amplitude distribution during various randomly-sampled identical time periods of a 60-Hz high-voltage wave. Described are properties of positive and negative corona impulses generated from typical conductors at various test high voltages. A possible method for calculating the energies, densities, and electromagnetic interferences by making use of these results is suggested.

  3. LONG DURATION FLARE EMISSION: IMPULSIVE HEATING OR GRADUAL HEATING?

    SciTech Connect

    Qiu, Jiong; Longcope, Dana W.

    2016-03-20

    Flare emissions in X-ray and EUV wavelengths have previously been modeled as the plasma response to impulsive heating from magnetic reconnection. Some flares exhibit gradually evolving X-ray and EUV light curves, which are believed to result from superposition of an extended sequence of impulsive heating events occurring in different adjacent loops or even unresolved threads within each loop. In this paper, we apply this approach to a long duration two-ribbon flare SOL2011-09-13T22 observed by the Atmosphere Imaging Assembly (AIA). We find that to reconcile with observed signatures of flare emission in multiple EUV wavelengths, each thread should be heated in two phases, an intense impulsive heating followed by a gradual, low-rate heating tail that is attenuated over 20–30 minutes. Each AIA resolved single loop may be composed of several such threads. The two-phase heating scenario is supported by modeling with both a zero-dimensional and a 1D hydrodynamic code. We discuss viable physical mechanisms for the two-phase heating in a post-reconnection thread.

  4. Magnetic dipole discharges. I. Basic properties

    SciTech Connect

    Stenzel, R. L.; Urrutia, J. M.; Teodorescu-Soare, C. T.; Ionita, C.; Schrittwieser, R.

    2013-08-15

    A simple discharge is described which uses a permanent magnet as a cold cathode and the metallic chamber wall as an anode. The magnet's equator is biased strongly negative, which produces secondary electrons due to the impact of energetic ions. The emitted electrons are highly confined by the strong dipolar magnetic field and the negative potential in the equatorial plane of the magnet. The emitted electrons ionize near the sheath and produce further electrons, which drift across field lines to the anode while the nearly unmagnetized ions are accelerated back to the magnet. A steady state discharge is maintained at neutral pressures above 10{sup −3} mbar. This is the principle of magnetron discharges, which commonly use cylindrical and planar cathodes rather than magnetic dipoles as cathodes. The discharge properties have been investigated in steady state and pulsed mode. Different magnets and geometries have been employed. The role of a background plasma has been investigated. Various types of instabilities have been observed such as sheath oscillations, current-driven turbulence, relaxation instabilities due to ionization, and high frequency oscillations created by sputtering impulses, which are described in more detail in companion papers. The discharge has also been operated in reactive gases and shown to be useful for sputtering applications.

  5. Optimal impulsive manoeuvres and aerodynamic braking

    NASA Technical Reports Server (NTRS)

    Jezewski, D. J.

    1985-01-01

    A method developed for obtaining solutions to the aerodynamic braking problem, using impulses in the exoatmospheric phases is discussed. The solution combines primer vector theory and the results of a suboptimal atmospheric guidance program. For a specified initial and final orbit, the solution determines: (1) the minimum impulsive cost using a maximum of four impulses, (2) the optimal atmospheric entry and exit-state vectors subject to equality and inequality constraints, and (3) the optimal coast times. Numerical solutions which illustrate the characteristics of the solution are presented.

  6. [Serotonin and impulsivity (experiments on animals)].

    PubMed

    Grigor'ian, G A

    2011-01-01

    In the current paper a role of the serotinergic system in organization of impulsive behaviour in animals was considered. The results of influence of antagonists and agonists of the different types and subtypes of 5-HT receptors (1A, B; 2A, B, C; 7) and the effects of the dorsal raphe nuclei lesions on characteristics of impulsivity related with a motor control, mechanisms of attention, reinforcement and decision making were summarized. The data on knock-out animals and the experiments with microdialysis have been also considered. There was emphasized the important role of interaction of 5-HT-, dopamine- and glutamatergic systems in mediation of impulsive behaviour.

  7. Two-impulse reorientation of asymmetric spacecraft

    NASA Technical Reports Server (NTRS)

    Martz, C. W.

    1979-01-01

    An investigation conducted to determine minimum maneuver costs for attitude reorientation of spacecraft of all possible inertial distribution over a wide range of maneuver angles by use of a two impulse coning method of reorientation is reported. Maneuver cost, proportional to the product of fuel consumed (total impulse) and time expended during a maneuver is discussed. Assumptions included external impulsive control torques, rigid body spacecraft rest-to-rest maneuvers, and no disturbance torques. Results are presented in terms of average cost and standard deviation for various maneuver ranges. Costs of individual reorientations are calculated with the computer program included.

  8. Identification of Experimental Unsteady Aerodynamic Impulse Responses

    NASA Technical Reports Server (NTRS)

    Silva, Walter A.; Piatak, David J.; Scott, Robert C.

    2003-01-01

    The identification of experimental unsteady aerodynamic impulse responses using the Oscillating Turntable (OTT) at NASA Langley's Transonic Dynamics Tunnel (TDT) is described. Results are presented for two configurations: a Rigid Semispan Model (RSM) and a rectangular wing with a supercritical airfoil section. Both models were used to acquire unsteady pressure data due to pitching oscillations on the OTT. A deconvolution scheme involving a step input in pitch and the resultant step response in pressure, for several pressure transducers, is used to identify the pressure impulse responses. The identified impulse responses are then used to predict the pressure response due to pitching oscillations at several frequencies. Comparisons with the experimental data are presented.

  9. Micropower impulse radar technology and applications

    SciTech Connect

    Mast, J., LLNL

    1998-04-15

    The LLNL-developed Micropower Impulse Radar (MIR) technology has quickly gone from laboratory concept to embedded circuitry in numerous government and commercial systems in the last few years[l]. The main ideas behind MIR, invented by T. McEwan in the Laser Program, are the generation and detection systems for extremely low- power ultra-wideband pulses in the gigaHertz regime using low-cost components. These ideas, coupled with new antenna systems, timing and radio-frequency (RF) circuitry, computer interfaces, and signal processing, have provided the catalyst for a new generation of compact radar systems. Over the past several years we have concentrated on a number of applications of MIR which address a number of remote-sensing applications relevant to emerging programs in defense, transportation, medical, and environmental research. Some of the past commercial successes have been widely publicized [2] and are only now starting to become available for market. Over 30 patents have been filed and over 15 licenses have been signed on various aspects of the MIR technology. In addition, higher performance systems are under development for specific laboratory programs and government reimbursables. The MIR is an ultra- wideband, range-gated radar system that provides the enabling hardware technology used in the research areas mentioned above. It has numerous performance parameters that can be Selected by careful design to fit the requirements. We have improved the baseline, short- range, MIR system to demonstrate its effectiveness. The radar operates over the hand from approximately I to 4 GHz with pulse repetition frequencies up to 10 MHz. It provides a potential range resolution of I cm at ranges of greater than 20 m. We have developed a suite of algorithms for using MIR for image formation. These algorithms currently support Synthetic aperture and multistate array geometries. This baseline MIR radar imaging system has been used for several programmatic applications.

  10. Dynamic response of clamped corrugated sandwich plates subjected to underwater impulsive loads

    NASA Astrophysics Data System (ADS)

    Huang, Wei; Zhang, Wei; Ye, Nan; Li, Dacheng

    2017-01-01

    Corrugated sandwich plates are widely used in marine industry because such plates have high strength-to-weight ratios and blast resistance. The laboratory-scaled fluid-structure interaction experiments are performed to demonstrate the shock resistance of corrugated sandwich plates by quantifying the permanent transverse deflection at mid-span of the plates as a function of impulsive loadings per areal mass. Sandwich structures with 6mm-thick 3003 H18 aluminum corrugated core and 5A06 face sheets subjected to underwater impulsive loadings are studied experimentally in this paper. The dynamic deformations of plates are captured with the the 3D digital imaging correlation method (DIC). The results affirm the peak deflection during the processes of dynamic deformation and the residual maximum deflection for post-mortem plates show a linear trend with the impulses per areal mass, and show sensitivity to the change of impulses. Inhomogeneous deformation for corrugated sandwich plates are show uneven rather than the perfect parabolic shapes reported in previous studies. With the increasing of intensities for impulsive loadings, the failure modes can be observed more complicated from the initial plastic deformation to debonding and crack. This paper provides valid data to quantify the peak deflection, residual deflection and failure modes as functions of impulses and geometric parameters in the future work.

  11. Distinct Facets of Impulsivity Exhibit Differential Associations with Substance Use Disorder Treatment Processes: A Cross-Sectional and Prospective Investigation Among Military Veterans

    PubMed Central

    Heinz, Adrienne J.; Bui, Leena; Thomas, Katherine M.; Blonigen, Daniel M.

    2015-01-01

    Impulsivity, a multi-faceted construct characterized by rash, unplanned actions and a disregard for long-term consequences, is associated with poor substance use disorder (SUD) treatment outcomes. Little is known though about the influence of impulsivity on treatment process variables critical for initiating and maintaining behavioral change. This knowledge gap is important as different aspects of impulsivity may be susceptible to diverse cognitive, behavioral and pharmacological influences. The present study examined two distinct facets of impulsivity (lack of planning and immoderation - a proxy of urgency) as predictors of processes that impact SUD treatment success (active coping, avoidant coping, self-efficacy, and interpersonal problems). Participants were 200 Veterans who completed impulsivity and treatment process assessments upon entering a SUD treatment program and treatment process assessments at treatment discharge. Results from multivariate models revealed that lack of planning was associated with lower active coping and higher avoidant coping and interpersonal problems at intake, though not with lower self-efficacy to abstain from substances. Immoderation was associated with higher avoidant coping and lower self-efficacy to abstain from substances at intake, but not with lower active coping or higher interpersonal problems. Higher immoderation, but not lack of planning, predicted lower self-efficacy to abstain from substances at treatment discharge. These findings suggest that different facets of impulsivity confer risk for different SUD treatment process indicators and that clinicians should consider the behavioral expression of patients’ impulse control problems in treatment planning and delivery. PMID:25770869

  12. GAS DISCHARGE DEVICES

    DOEpatents

    Arrol, W.J.; Jefferson, S.

    1957-08-27

    The construction of gas discharge devices where the object is to provide a gas discharge device having a high dark current and stabilized striking voltage is described. The inventors have discovered that the introduction of tritium gas into a discharge device with a subsequent electrical discharge in the device will deposit tritium on the inside of the chamber. The tritium acts to emit beta rays amd is an effective and non-hazardous way of improving the abovementioned discharge tube characteristics

  13. Impulse control disorders in Parkinson's disease: decreased striatal dopamine transporter levels

    PubMed Central

    Voon, Valerie; Rizos, Alexandra; Chakravartty, Riddhika; Mulholland, Nicola; Robinson, Stephanie; Howell, Nicholas A; Harrison, Neil; Vivian, Gill; Ray Chaudhuri, K

    2014-01-01

    Objective Impulse control disorders are commonly associated with dopaminergic therapy in Parkinson's disease (PD). PD patients with impulse control disorders demonstrate enhanced dopamine release to conditioned cues and a gambling task on [11C]raclopride positron emission tomography (PET) imaging and enhanced ventral striatal activity to reward on functional MRI. We compared PD patients with impulse control disorders and age-matched and gender-matched controls without impulse control disorders using [123I]FP-CIT (2β-carbomethoxy-3β-(4-iodophenyl)tropane) single photon emission computed tomography (SPECT), to assess striatal dopamine transporter (DAT) density. Methods The [123I]FP-CIT binding data in the striatum were compared between 15 PD patients with and 15 without impulse control disorders using independent t tests. Results Those with impulse control disorders showed significantly lower DAT binding in the right striatum with a trend in the left (right: F(1,24)=5.93, p=0.02; left: F(1,24)=3.75, p=0.07) compared to controls. Conclusions Our findings suggest that greater dopaminergic striatal activity in PD patients with impulse control disorders may be partly related to decreased uptake and clearance of dopamine from the synaptic cleft. Whether these findings are related to state or trait effects is not known. These findings dovetail with reports of lower DAT levels secondary to the effects of methamphetamine and alcohol. Although any regulation of DAT by antiparkinsonian medication appears to be modest, PD patients with impulse control disorders may be differentially sensitive to regulatory mechanisms of DAT expression by dopaminergic medications. PMID:23899625

  14. Impulsively generated fast coronal pulsations

    NASA Technical Reports Server (NTRS)

    Edwin, P. M.; Roberts, B.

    1986-01-01

    Rapid oscillations in the corona are discussed from a theoretical standpoint, developing some previous work on ducted, fast magnetoacoustic waves in an inhomogeneous medium. In the theory, impulsively (e.g., flare) generated mhd (magnetohydrodynamic) waves are ducted by regions of low Alfven speed (high density) such as coronal loops. Wave propagation in such ducts is strongly dispersive and closely akin to the behavior of Love waves in seismology, Pekeris waves in oceanography and guided waves in fiber optics. Such flare-generated magnetoacoustic waves possess distinctive temporal signatures consisting of periodic, quasi-periodic and decay phases. The quasi-periodic phase possesses the strongest amplitudes and the shortest time scales. Time scales are typically of the order of a second for inhomogeneities (coronal loop width) of 1000 km and Alfven speeds of 1000/kms, and pulse duration times are of tens of seconds. Quasi-periodic signatures have been observed in radio wavelengths for over a decade and more recently by SMM. It is hoped that the theoretical ideas outlined may be successfully related to these observations and thus aid the interpretation of oscillatory signatures recorded by SMM. Such signatures may also provide a diagnostic of coronal conditions. New aspects of the ducted mhd waves, for example their behavior in smoothly varying as opposed to tube-like inhomogeneities, are currently under investigation. The theory is not restricted to loops but applied equally to open field regions.

  15. Specific Impulse Definition for Ablative Laser Propulsion

    NASA Technical Reports Server (NTRS)

    Herren, Kenneth A.; Gregory, Don A.

    2004-01-01

    The term "specific impulse" is so ingrained in the field of rocket propulsion that it is unlikely that any fundamental argument would be taken seriously for its removal. It is not an ideal measure but it does give an indication of the amount of mass flow (mass loss/time), as in fuel rate, required to produce a measured thrust over some time period This investigation explores the implications of being able to accurately measure the ablation rate and how the language used to describe the specific impulse results may have to change slightly, and recasts the specific impulse as something that is not a time average. It is not currently possible to measure the ablation rate accurately in real time so it is generally just assumed that a constant amount of material will be removed for each laser pulse delivered The specific impulse dependence on the ablation rate is determined here as a correction to the classical textbook definition.

  16. Impulsive behaviour in interpersonal encounters: associations with quarrelsomeness and agreeableness.

    PubMed

    aan Het Rot, Marije; Moskowitz, D S; Young, Simon N

    2015-02-01

    Associations between impulsivity and interpersonal behaviours have rarely been examined, even though impulsivity may disrupt the flow of social interactions. For example, it is unknown to what extent the commonly used Barratt Impulsiveness Scale (BIS-11) predicts impulsive behaviour in social situations, and how behaving impulsively during interpersonal encounters might influence levels of quarrelsomeness and agreeableness. In this study, 48 healthy working individuals completed the BIS-11 and recorded their behaviour in social situations using event-contingent recording. Record forms included items representing quarrelsome, agreeable, and impulsive behaviours. BIS-11 motor impulsiveness scores predicted impulsive behaviour in social situations. Impulsive behaviour was associated, in different interactions, with both agreeableness and quarrelsomeness. Behaving impulsively in specific interactions was negatively associated with agreeableness in participants with higher BIS-11 motor impulsiveness and positively associated with agreeableness in participants with lower BIS-11 motor impulsiveness. Impulsive quarrelsome behaviour may cause interpersonal problems. Impulsive agreeable behaviour may have positive effects in individuals with low trait impulsivity. The idea that there are between-person differences in the effects of state impulsivity on the flow of social interaction deserves further study.

  17. Multi-impulsivity of Japanese patients with eating disorders: primary and secondary impulsivity.

    PubMed

    Nagata, T; Kawarada, Y; Kiriike, N; Iketani, T

    2000-07-17

    Several studies have noted that multi-impulsive bulimia nervosa tends to be refractory to treatment. However, it is not known whether these impulsivities are an expression of more fundamental psychopathology or simply the consequence of chaotic eating behaviors. Studies of the temporal relationship between the onset of eating disorder and the occurrence of impulsive behaviors will facilitate a better understanding of these issues. Subjects consisted of 60 patients with anorexia nervosa restricting type (AN-R), 62 patients with anorexia nervosa binge-eating/purging type (AN-BP), 114 patients with bulimia nervosa purging type (BN) and 66 control subjects. Impulsive behaviors and childhood traumatic experiences were assessed by self-report questionnaire. Multi-impulsivity (defined by at least three of the following: heavy regular alcohol drinking; suicide attempt; self-mutilation; repeated shoplifting of items other than food; sexual relationships with persons not well known to the subject) was found in 2% of AN-R, 11% of AN-BP, 18% of BN and 2% of control subjects. Eighty percent of BN patients with multi-impulsivity had a history of suicide attempts or self-mutilation history prior to the onset of bulimia nervosa. In BN patients, there tended to be a relationship between childhood parental loss or borderline personality disorder and multi-impulsivity. In conclusion, primary impulsivity (chronological prior occurrence of impulsive behaviors) does exist even in a very different culture, although the number of patients of this type is very limited.

  18. Impulsive Social Influence Increases Impulsive Choices on a Temporal Discounting Task in Young Adults

    PubMed Central

    Gilman, Jodi M.; Curran, Max T.; Calderon, Vanessa; Stoeckel, Luke E.; Evins, A. Eden

    2014-01-01

    Adolescents and young adults who affiliate with friends who engage in impulsive behavior are more likely to engage in impulsive behaviors themselves, and those who associate with prosocial (i.e. more prudent, future oriented) peers are more likely to engage in prosocial behavior. However, it is difficult to disentangle the contribution of peer influence vs. peer selection (i.e., whether individuals choose friends with similar traits) when interpreting social behaviors. In this study, we combined a novel social manipulation with a well-validated delay discounting task assessing impulsive behavior to create a social influence delay discounting task, in which participants were exposed to both impulsive (smaller, sooner or SS payment) and non-impulsive (larger, later or LL payment) choices from their peers. Young adults in this sample, n = 51, aged 18–25 had a higher rate of SS choices after exposure to impulsive peer influence than after exposure to non-impulsive peer influence. Interestingly, in highly susceptible individuals, the rate of non-impulsive choices did not increase after exposure to non-impulsive influence. There was a positive correlation between self-reported suggestibility and degree of peer influence on SS choices. These results suggest that, in young adults, SS choices appear to be influenced by the choices of same-aged peers, especially for individuals who are highly susceptible to influence. PMID:24988440

  19. Specific Impulse and Mass Flow Rate Error

    NASA Technical Reports Server (NTRS)

    Gregory, Don A.

    2005-01-01

    Specific impulse is defined in words in many ways. Very early in any text on rocket propulsion a phrase similar to .specific impulse is the thrust force per unit propellant weight flow per second. will be found.(2) It is only after seeing the mathematics written down does the definition mean something physically to scientists and engineers responsible for either measuring it or using someone.s value for it.

  20. Dysfunctional, but not functional, impulsivity is associated with a history of seriously violent behaviour and reduced orbitofrontal and hippocampal volumes in schizophrenia.

    PubMed

    Kumari, Veena; Barkataki, Ian; Goswami, Sangeeta; Flora, Satinder; Das, Mrigendra; Taylor, Pamela

    2009-07-15

    Aggression and violent acts have been linked with impulsive responding. We investigated whether impulsive personality trait, especially suggestive of dysfunctional impulsivity (i.e. fast and inaccurate responding where this is non-optimal), is associated with a history of seriously violent behaviour and specific brain deficits in schizophrenia. Twenty-four male participants with schizophrenia, of whom 10 had a history of serious physical violence, and 14 healthy male participants were assessed on impulsiveness (dysfunctional impulsivity), venturesomeness (functional impulsivity), and empathy. All participants underwent magnetic resonance imaging. The results revealed that participants with schizophrenia and a history of violence showed elevated impulsiveness but had comparable scores on venturesomeness and empathy dimensions. Impulsiveness scores correlated negatively with reduced orbitofrontal grey matter volume in both the patient and healthy control groups, and with hippocampal volume in the patient group. Our findings suggest that dysfunctional, but not functional, impulsivity is elevated in patients with schizophrenia with a propensity for repetitive violence, and this in turn appears to be associated with reduce volumes of both the orbitofrontal cortex grey matter and the hippocampus. Violence risk prediction and management strategies in schizophrenia may benefit from including specific measures of dysfunctional impulsive traits.

  1. Temporal preparation, response inhibition and impulsivity.

    PubMed

    Correa, Angel; Triviño, Mónica; Pérez-Dueñas, Carolina; Acosta, Alberto; Lupiáñez, Juan

    2010-08-01

    Temporal preparation and impulsivity involve overlapping neural structures (prefrontal cortex) and cognitive functions (response inhibition and time perception), however, their interrelations had not been investigated. We studied such interrelations by comparing the performance of groups with low vs. high non-clinical trait impulsivity during a temporal preparation go no-go task. This task measured, in less than 10 min, how response inhibition was influenced both by temporal orienting of attention (guided by predictive temporal cues) and by sequential effects (produced by repetition/alternation of the duration of preparatory intervals in consecutive trials). The results showed that sequential effects produced dissociable patterns of temporal preparation as a function of impulsivity. Sequential effects facilitated both response speed (reaction times - RTs - to the go condition) and response inhibition (false alarms to the no-go condition) selectively in the low impulsivity group. In the high impulsivity group, in contrast, sequential effects only improved RTs but not response inhibition. We concluded that both excitatory and inhibitory processing may be enhanced concurrently by sequential effects, which enables the temporal preparation of fast and controlled responses. Impulsivity could hence be related to less efficient temporal preparation of that inhibitory processing.

  2. Refinement and application of acoustic impulse technique to study nozzle transmission characteristics

    NASA Technical Reports Server (NTRS)

    Salikuddin, M.; Brown, W. H.; Ramakrishnan, R.; Tanna, H. K.

    1983-01-01

    An improved acoustic impulse technique was developed and was used to study the transmission characteristics of duct/nozzle systems. To accomplish the above objective, various problems associated with the existing spark-discharge impulse technique were first studied. These included (1) the nonlinear behavior of high intensity pulses, (2) the contamination of the signal with flow noise, (3) low signal-to-noise ratio at high exhaust velocities, and (4) the inability to control or shape the signal generated by the source, specially when multiple spark points were used as the source. The first step to resolve these problems was the replacement of the spark-discharge source with electroacoustic driver(s). These included (1) synthesizing on acoustic impulse with acoustic driver(s) to control and shape the output signal, (2) time domain signal averaging to remove flow noise from the contaminated signal, (3) signal editing to remove unwanted portions of the time history, (4) spectral averaging, and (5) numerical smoothing. The acoustic power measurement technique was improved by taking multiple induct measurements and by a modal decomposition process to account for the contribution of higher order modes in the power computation. The improved acoustic impulse technique was then validated by comparing the results derived by an impedance tube method. The mechanism of acoustic power loss, that occurs when sound is transmitted through nozzle terminations, was investigated. Finally, the refined impulse technique was applied to obtain more accurate results for the acoustic transmission characteristics of a conical nozzle and a multi-lobe multi-tube supressor nozzle.

  3. A computational investigation of impulsive and pulsed starting annular jets

    NASA Astrophysics Data System (ADS)

    Abdel-Raouf, Emad Mohamed Refaat

    2011-12-01

    A computational study is carried out on low Reynolds number impulsive and pulsating annular jets. This work is inspired by the biological flow of marine life that uses jet propulsion for self maneuver. Marine life such as squids and jellyfish propel themselves by discharging a water jet followed by a refilling phase. The discharging portion is a starting jet, i.e. the releasing of a moving fluid into a quiescent fluid, while the refilling phase can be viewed as an inflow jet. The combined jets will be called fully oscillating jets. Although fully oscillating jets have been indirectly examined experimentally, they have never been studied computationally. This dissertation is divided into three investigations that examine the starting jet, inflow jet, and fully oscillating jet based on the resultant force (i.e. either thrust or suction force) at the annulus exit plane, jet efficiency, and vortex dynamics. Furthermore, each of the following three performance criterion is examined under various velocity imposed boundaries (i.e. impulsive, unit pulsed, and sinusoidal pulsed jets), ambient pressure, and blocking ratios. An axisymmetric, incompressible and unsteady Navier Stokes numerical model was used to implement the analysis. The model was validated against theoretical and experimental results, where both result types bounded the computational results of this endeavor. In addition, numerical verification was carried out on each of the three investigations ensuring grid and time independent results. Several substantial outcomes were drawn from the results of the three investigations. The numerical results confirmed previously published experimental data regarding the universal dimensionless time scale (i.e. vortex formation number) of optimal vortex ring development triggered by starting jets. Moreover, the computational results showed evidence that the vortex formation number was not affected by ambient pressure nor blocking ratio. The computational results also

  4. Genetic and Modeling Approaches Reveal Distinct Components of Impulsive Behavior.

    PubMed

    Nautiyal, Katherine M; Wall, Melanie M; Wang, Shuai; Magalong, Valerie M; Ahmari, Susanne E; Balsam, Peter D; Blanco, Carlos; Hen, René

    2017-01-18

    Impulsivity is an endophenotype found in many psychiatric disorders including substance use disorders, pathological gambling, and attention deficit hyperactivity disorder. Two behavioral features often considered in impulsive behavior are behavioral inhibition (impulsive action) and delayed gratification (impulsive choice). However, the extent to which these behavioral constructs represent distinct facets of behavior with discrete biological bases is unclear. To test the hypothesis that impulsive action and impulsive choice represent statistically independent behavioral constructs in mice, we collected behavioral measures of impulsivity in a single cohort of mice using well-validated operant behavioral paradigms. Mice with manipulation of serotonin 1B receptor (5-HT1BR) expression were included as a model of disordered impulsivity. A factor analysis was used to characterize correlations between the measures of impulsivity and to identify covariates. Using two approaches, we dissociated impulsive action from impulsive choice. First, the absence of 5-HT1BRs caused increased impulsive action, but not impulsive choice. Second, based on an exploratory factor analysis, a two-factor model described the data well, with measures of impulsive action and choice separating into two independent factors. A multiple-indicator multiple-causes analysis showed that 5-HT1BR expression and sex were significant covariates of impulsivity. Males displayed increased impulsivity in both dimensions, whereas 5-HT1BR expression was a predictor of increased impulsive action only. These data support the conclusion that impulsive action and impulsive choice are distinct behavioral phenotypes with dissociable biological influences that can be modeled in mice. Our work may help inform better classification, diagnosis, and treatment of psychiatric disorders, which present with disordered impulsivity.Neuropsychopharmacology advance online publication, 18 January 2017; doi:10.1038/npp.2016.277.

  5. Angioplasty and stent placement - peripheral arteries - discharge

    MedlinePlus

    Percutaneous transluminal angioplasty - peripheral artery - discharge; PTA - peripheral artery - discharge; Angioplasty - peripheral artery - discharge; Balloon angioplasty - peripheral artery- discharge; PAD - PTA discharge; PVD - PTA discharge

  6. Further evidence of the heterogeneous nature of impulsivity.

    PubMed

    Caswell, Amy J; Bond, Rod; Duka, Theodora; Morgan, Michael J

    2015-04-01

    'Impulsivity' refers to a range of behaviours including preference for immediate reward (temporal-impulsivity) and the tendency to make premature decisions (reflection-impulsivity) and responses (motor-impulsivity). The current study aimed to examine how different behavioural and self-report measurements of impulsivity can be categorised into distinct subtypes. Exploratory factor analysis using full information maximum likelihood was conducted on 10 behavioural and 1 self-report measure of impulsivity. Four factors of impulsivity were indicated, with Factor 1 having a high loading of the Stop Signal Task, which measures motor-impulsivity, factor 2 representing reflection-impulsivity with loadings of the Information Sampling Task and Matching Familiar Figures Task, factor 3 representing the Immediate Memory Task, and finally factor 4 which represents the Delay Discounting Questionnaire and The Monetary Choice Questionnaire, measurements of temporal-impulsivity. These findings indicated that impulsivity is not a unitary construct, and instead represents a series of independent subtypes. There was evidence of a distinct reflection-impulsivity factor, providing the first factor analysis support for this subtype. There was also support for additional factors of motor- and temporal-impulsivity. The present findings indicated that a number of currently accepted tasks cannot be considered as indexing motor- and temporal-impulsivity suggesting that additional characterisations of impulsivity may be required.

  7. Physics and Chemistry of MW Discharge in Gas Flows

    DTIC Science & Technology

    2007-11-02

    this working regime of wind tunnel. Measurement was carried out by means of pneumatic probes. 1.1.1. Experimental conditions Nozzle with Mach number 2.1...unstable objects may be Laser Thomson Scattering Technique. Created laser Thomson Final Report 30 July, 2004 Project 2014p IHT-SPSU scattering...experimental scheme for investigation of Thomson scattering in MW discharge in SS flow with static pressure 20 - 50 Torr and Mach number 1.5 - 2. Impulse

  8. Gamma Aminobutyric Acidergic and Neuronal Structural Markers in the Nucleus Accumbens Core Underlie Trait-like Impulsive Behavior

    PubMed Central

    Caprioli, Daniele; Sawiak, Stephen J.; Merlo, Emiliano; Theobald, David E.H.; Spoelder, Marcia; Jupp, Bianca; Voon, Valerie; Carpenter, T. Adrian; Everitt, Barry J.; Robbins, Trevor W.; Dalley, Jeffrey W.

    2014-01-01

    Background Pathological forms of impulsivity are manifest in a number of psychiatric disorders listed in DSM-5, including attention-deficit/hyperactivity disorder and substance use disorder. However, the molecular and cellular substrates of impulsivity are poorly understood. Here, we investigated a specific form of motor impulsivity in rats, namely premature responding, on a five-choice serial reaction time task. Methods We used in vivo voxel-based magnetic resonance imaging and ex vivo Western blot analyses to investigate putative structural, neuronal, and glial protein markers in low-impulsive (LI) and high-impulsive rats. We also investigated whether messenger RNA interference targeting glutamate decarboxylase 65/67 (GAD65/67) gene expression in the nucleus accumbens core (NAcbC) is sufficient to increase impulsivity in LI rats. Results We identified structural and molecular abnormalities in the NAcbC associated with motor impulsivity in rats. We report a reduction in gray matter density in the left NAcbC of high-impulsive rats, with corresponding reductions in this region of glutamate decarboxylase (GAD65/67) and markers of dendritic spines and microtubules. We further demonstrate that the experimental reduction of de novo of GAD65/67 expression bilaterally in the NAcbC is sufficient to increase impulsivity in LI rats. Conclusions These results reveal a novel mechanism of impulsivity in rats involving gamma aminobutyric acidergic and structural abnormalities in the NAcbC with potential relevance to the etiology and treatment of attention-deficit/hyperactivity disorder and related disorders. PMID:23973096

  9. Transition Region and Chromospheric Signatures of Impulsive Heating Events. I. Observations

    NASA Astrophysics Data System (ADS)

    Warren, Harry P.; Reep, Jeffrey W.; Crump, Nicholas A.; Simões, Paulo J. A.

    2016-09-01

    We exploit the high spatial resolution and high cadence of the Interface Region Imaging Spectrograph (IRIS) to investigate the response of the transition region and chromosphere to energy deposition during a small flare. Simultaneous observations from the Reuven Ramaty High Energy Solar Spectroscopic Imager provide constraints on the energetic electrons precipitating into the flare footpoints, while observations of the X-Ray Telescope, Atmospheric Imaging Assembly, and Extreme Ultraviolet Imaging Spectrometer (EIS) allow us to measure the temperatures and emission measures from the resulting flare loops. We find clear evidence for heating over an extended period on the spatial scale of a single IRIS pixel. During the impulsive phase of this event, the intensities in each pixel for the Si iv 1402.770 Å, C ii 1334.535 Å, Mg ii 2796.354 Å, and O i 1355.598 Å emission lines are characterized by numerous small-scale bursts typically lasting 60 s or less. Redshifts are observed in Si iv, C ii, and Mg ii during the impulsive phase. Mg ii shows redshifts during the bursts and stationary emission at other times. The Si iv and C ii profiles, in contrast, are observed to be redshifted at all times during the impulsive phase. These persistent redshifts are a challenge for one-dimensional hydrodynamic models, which predict only short-duration downflows in response to impulsive heating. We conjecture that energy is being released on many small-scale filaments with a power-law distribution of heating rates.

  10. Impulsivity, frontal lobes and risk for addiction.

    PubMed

    Crews, Fulton Timm; Boettiger, Charlotte Ann

    2009-09-01

    Alcohol and substance abuse disorders involve continued use of substances despite negative consequences, i.e. loss of behavioral control of drug use. The frontal-cortical areas of the brain oversee behavioral control through executive functions. Executive functions include abstract thinking, motivation, planning, attention to tasks and inhibition of impulsive responses. Impulsiveness generally refers to premature, unduly risky, poorly conceived actions. Dysfunctional impulsivity includes deficits in attention, lack of reflection and/or insensitivity to consequences, all of which occur in addiction [Evenden JL. Varieties of impulsivity. Psychopharmacology (Berl) 1999;146:348-361.; de Wit H. Impulsivity as a determinant and consequence of drug use: a review of underlying processes. Addict Biol 2009;14:22-31]. Binge drinking models indicate chronic alcohol damages in the corticolimbic brain regions [Crews FT, Braun CJ, Hoplight B, Switzer III RC, Knapp DJ. Binge ethanol consumption causes differential brain damage in young adolescent rats compared with adult rats. Alcohol Clin Exp Res 2000;24:1712-1723] causing reversal learning deficits indicative of loss of executive function [Obernier JA, White AM, Swartzwelder HS, Crews FT. Cognitive deficits and CNS damage after a 4-day binge ethanol exposure in rats. Pharmacol Biochem Behav 2002b;72:521-532]. Genetics and adolescent age are risk factors for alcoholism that coincide with sensitivity to alcohol-induced neurotoxicity. Cortical degeneration from alcohol abuse may increase impulsivity contributing to the development, persistence and severity of alcohol use disorders. Interestingly, abstinence results in bursts of neurogenesis and brain regrowth [Crews FT, Nixon K. Mechanisms of neurodegeneration and regeneration in alcoholism. Alcohol Alcohol 2009;44:115-127]. Treatments for alcoholism, including naltrexone pharmacotherapy and psychotherapy may work through improving executive functions. This review will examine the

  11. Characterization of impulse noise and hazard analysis of impulse noise induced hearing loss using AHAAH modeling

    NASA Astrophysics Data System (ADS)

    Wu, Qing

    Millions of people across the world are suffering from noise induced hearing loss (NIHL), especially under working conditions of either continuous Gaussian or non-Gaussian noise that might affect human's hearing function. Impulse noise is a typical non-Gaussian noise exposure in military and industry, and generates severe hearing loss problem. This study mainly focuses on characterization of impulse noise using digital signal analysis method and prediction of the auditory hazard of impulse noise induced hearing loss by the Auditory Hazard Assessment Algorithm for Humans (AHAAH) modeling. A digital noise exposure system has been developed to produce impulse noises with peak sound pressure level (SPL) up to 160 dB. The characterization of impulse noise generated by the system has been investigated and analyzed in both time and frequency domains. Furthermore, the effects of key parameters of impulse noise on auditory risk unit (ARU) are investigated using both simulated and experimental measured impulse noise signals in the AHAAH model. The results showed that the ARUs increased monotonically with the peak pressure (both P+ and P-) increasing. With increasing of the time duration, the ARUs increased first and then decreased, and the peak of ARUs appeared at about t = 0.2 ms (for both t+ and t-). In addition, the auditory hazard of experimental measured impulse noises signals demonstrated a monotonically increasing relationship between ARUs and system voltages.

  12. Controlling your impulses: electrical stimulation of the human supplementary motor complex prevents impulsive errors.

    PubMed

    Spieser, Laure; van den Wildenberg, Wery; Hasbroucq, Thierry; Ridderinkhof, K Richard; Burle, Borís

    2015-02-18

    To err is human. However, an inappropriate urge does not always result in error. Impulsive errors thus entail both a motor system capture by an urge to act and a failed inhibition of that impulse. Here we show that neuromodulatory electrical stimulation of the supplementary motor complex in healthy humans leaves action urges unchanged but prevents them from turning into overt errors. Subjects performed a choice reaction-time task known to trigger impulsive responses, leading to fast errors that can be revealed by analyzing accuracy as a function of poststimulus time. Yet, such fast errors are only the tip of the iceberg: electromyography (EMG) revealed fast subthreshold muscle activation in the incorrect response hand in an even larger proportion of overtly correct trials, revealing covert response impulses not discernible in overt behavior. Analyzing both overt and covert response tendencies enables to gauge the ability to prevent these incorrect impulses from turning into overt action errors. Hyperpolarizing the supplementary motor complex using transcranial direct current stimulation (tDCS) preserves action impulses but prevents their behavioral expression. This new combination of detailed behavioral, EMG, and tDCS techniques clarifies the neurophysiology of impulse control, and may point to avenues for improving impulse control deficits in various neurologic and psychiatric disorders.

  13. Impulsivity and psychopathy: associations between the barrett impulsivity scale and the psychopathy checklist revised.

    PubMed

    Snowden, Robert J; Gray, Nicola S

    2011-05-30

    Impulsivity is often cited as a core dysfunction in those who are high in psychopathic traits. However, both impulsivity and psychopathy are both multi-faceted constructs. We examined a 3-factor model of self-reported impulsivity (Barrett Impulsivity: BIS-11) against the 2-factor and 4-facet model of psychopathy as defined by the Psychopathy Checklist-Revised (PCL-R). Those high on 'secondary psychopathy' (Factor 2 and Facets 3 and 4 of the PCL-R) showed increased impulsivity as it related to acting with thinking (Motor Scale of BIS) and lack of future planning (Non-Planning scale of BIS), but not did not show any elevated features of poor concentration or distraction (Attention Scale of BIS). On the other hand, there was some evidence that 'primary psychopathy' (Factor 1 of PCL-R) was associated with reduced impulsivity as it relates to future planning (Non-Planning scale of BIS). Thus, our results show that only some psychopaths show increased impulsivity and that not all forms of impulsivity are raised.

  14. Vessel Sewage Discharges

    EPA Pesticide Factsheets

    Vessel sewage discharges are regulated under Section 312 of the Clean Water Act, which is jointly implemented by the EPA and Coast Guard. This homepage links to information on marine sanitation devices and no discharge zones.

  15. Site of impulse initiation in tendon organs of cat soleus muscle.

    PubMed

    Gregory, J E; Morgan, D L; Proske, U

    1985-12-01

    A continuing controversy surrounds the question of whether Golgi tendon organs are examples of receptors in which impulses may be generated at more than one site. This paper reports a systematic examination of a number of models incorporating single or multiple impulse generators and of the compatibility of their predictions with experimental observations. Two phenomena, in particular, that must be accounted for are nonlinear summation and cross-adaptation. When two motor units each with a direct effect on the tendon organ are stimulated together, the rate of discharge is greater than either individual rate but is less than their sum. In cross-adaptation a conditioning response elicited by one motor unit contraction produces adaptation of the discharge associated with stimulation of a second motor unit. A model with a central impulse generator can be modified to account for nonlinear summation by postulating a nonlinear transformation in the generator current-to-impulse rate conversion. Experiments measuring summation of responses to stimulation of three inputs produced results that did not support this model. Another variation of the model, which had a nonlinearity in the tension-to-current step and cross-connections (mechanical or neural) between tendon strands stressed by contracting muscle fibers, was able to account for the observations. A second model that provided the right predictions was a multiple impulse generator with cross-connections. Which of the two models best fits the experimental observations can be decided by comparing the calculated summation coefficients and cross-adaptation coefficients. A central impulse generator predicts a negative correlation, the multiple impulse generator a positive correlation. All of the observations were made using tendon organs of cat soleus muscle. Responses were recorded to stimulation of filaments of ventral root. In a comparison between 20 pairs of responses from six tendon organs the correlation between

  16. Reactive high power impulse magnetron sputtering: combining simulation and experiment

    NASA Astrophysics Data System (ADS)

    Kozak, Tomas; Vlcek, Jaroslav

    2016-09-01

    Reactive high-power impulse magnetron sputtering (HiPIMS) has recently been used for preparation of various oxide films with high application potential, such as TiO2, ZrO2, Ta2O5, HfO2, VO2. Using our patented method of pulsed reactive gas flow control with an optimized reactive gas inlet, we achieved significantly higher deposition rates compared to typical continuous dc magnetron depositions. We have developed a time-dependent model of the reactive HiPIMS. The model includes a depth-resolved description of the sputtered target (featuring sputtering, implantation and knock-on implantation processes) and a parametric description of the discharge plasma (dissociation of reactive gas, ionization and return of sputtered atoms and gas rarefaction). The model uses a combination of experimental and simulation data as input. We have calculated the composition of the target and substrate for several deposition conditions. The simulations predict a reduced compound coverage of the target in HiPIMS compared to the continuous dc sputtering regime which explains the increased deposition rate. The simulations show that an increased dissociation of oxygen in a HiPIMS discharge is beneficial to achieve stoichiometric films on the substrate at high deposition rates.

  17. Solar Flare Impulsive Phase Observations from SDO and Other Observatories

    NASA Technical Reports Server (NTRS)

    Chamberlin, Phillip C.; Woods, Thomas N.; Schrijver, Karel; Warren, Harry; Milligan, Ryan; Christe, Steven; Brosius, Jeffrey W.

    2010-01-01

    With the start of normal operations of the Solar Dynamics Observatory in May 2010, the Extreme ultraviolet Variability Experiment (EVE) and the Atmospheric Imaging Assembly (AIA) have been returning the most accurate solar XUV and EUV measurements every 10 and 12 seconds, respectively, at almost 100% duty cycle. The focus of the presentation will be the solar flare impulsive phase observations provided by EVE and AIA and what these observations can tell us about the evolution of the initial phase of solar flares. Also emphasized throughout is how simultaneous observations with other instruments, such as RHESSI, SOHO-CDS, and HINODE-EIS, will help provide a more complete characterization of the solar flares and the evolution and energetics during the impulsive phase. These co-temporal observations from the other solar instruments can provide information such as extending the high temperature range spectra and images beyond that provided by the EUV and XUV wavelengths, provide electron density input into the lower atmosphere at the footpoints, and provide plasma flows of chromospheric evaporation, among other characteristics.

  18. Pediatric heart surgery - discharge

    MedlinePlus

    ... get enough calories to heal and grow. After heart surgery, most babies and infants (younger than 12 to 15 months) can take ... valve surgery - children - discharge; Heart surgery - pediatric - discharge; Heart transplant - pediatric - discharge ... open heart surgery References Bernstein D. General principles ...

  19. Impulsivity and personality variables in adolescents with eating disorders.

    PubMed

    Boisseau, Christina L; Thompson-Brenner, Heather; Eddy, Kamryn T; Satir, Dana A

    2009-04-01

    Impulsivity among individuals with eating disorders (EDs) is associated with severe comorbidities and poor treatment outcome. However, research investigating the construct of impulsivity in EDs is limited. The objectives of the present study were to characterize multiple dimensions of impulsivity in adolescents with EDs; determine if differences in impulsivity were associated with ED diagnosis and/or broader personality traits; and explore the relationship between impulsivity and etiologically significant variables. Experienced clinicians from a practice-research network provided data on ED symptoms, impulsive characteristics, personality pathology, The Diagnostic and Statistical Manual of Mental Disorders comorbidity, and family and developmental history for 120 adolescent patients with EDs. Three distinct types of impulsivity were identified: general, acting out, and aggressive/destructive. The impulsivity types showed specific relationships to ED diagnosis, broader personality factors, individual histories of adverse (traumatic) events, and family histories of externalizing disorders, supporting the importance of taking, assessing, and addressing impulsivity in ED research and treatment.

  20. Ultrastructural and cytochemical evidence for single impulse initiation zones in vestibular macular nerve fibers of rat

    NASA Technical Reports Server (NTRS)

    Ross, Muriel D.; Chee, Oliver; Black, Samuel; Cutler, Lynn

    1991-01-01

    Cupric ion-ferricyanide labeling methods and related ferrocyanide-stained tissues were used to locate the characterize, at the ultrastructural level, presumptive impulse initiation zones in the three types of vestibular macular nerve fibers. Large-diameter, M-type vestibular nerve fibers terminate in a calyx at the heminode, and labeling is coextensive with the base of the calyx. Intermediate, M/U-type nerve fibers have short, unmyelinated preterminal segments that sometimes bifurcate intamacularly, and small-diameter, U-type nerve fibers have long, unmyelinated preterminal axons and up to three branches. Preterminals of these nerve fibers display ultrastructural heterogeneity that is correlated with labeling patterns for sodium channels and/or associated polyanionic sites. They have a nodelike ultrastructure and label heavily from near the heminode to the base of the macula. Their intramacular branches, less organized ultrastructurally, label only slightly. Results indicate that vestibular nerve fibers have one impulse initiation zone, located near the heminode, that varies in length according to nerve fiber type. Structural heterogeneity may favor impulse conduction in the central direction, and length of the impulse initiation zone could influence nerve discharge patterns.

  1. How Many Impulsivities? A Discounting Perspective

    PubMed Central

    Green, Leonard; Myerson, Joel

    2014-01-01

    People discount the value of delayed and uncertain outcomes, and how steeply individuals discount is thought to reflect how impulsive they are. From this perspective, steep discounting of delayed outcomes (which fails to maximize long-term welfare) and shallow discounting of probabilistic outcomes (which fails to adequately take risk into account) reflect the same trait of impulsivity. Despite the fact that a hyperboloid function describes the discounting of both delayed and probabilistic outcomes, there is considerable evidence that the two kinds of discounting involve different processes as well as separate impulsivity traits. Several manipulations differentially affect delay and probability discounting, and correlational studies show that how steeply one discounts delayed rewards is relatively independent of how steeply one discounts probabilistic rewards. Moreover, people’s discounting of delayed money and health outcomes are uncorrelated as are discounting of real, consumable rewards and hypothetical money. These results suggest that even within delay discounting, there may be multiple ‘impulsivities,’ each of which may be important for understanding a different aspect of decision making. Taken together, the pattern of findings reviewed here argues for a more nuanced view of impulsivity than that which is usually assumed in discounting research. PMID:23344985

  2. Entrainment and the cranial rhythmic impulse.

    PubMed

    McPartland, J M; Mein, E A

    1997-01-01

    Entrainment is the integration or harmonization of oscillators. All organisms pulsate with myriad electrical and mechanical rhythms. Many of these rhythms emanate from synchronized pulsating cells (eg, pacemaker cells, cortical neurons). The cranial rhythmic impulse is an oscillation recognized by many bodywork practitioners, but the functional origin of this impulse remains uncertain. We propose that the cranial rhythmic impulse is the palpable perception of entrainment, a harmonic frequency that incorporates the rhythms of multiple biological oscillators. It is derived primarily from signals between the sympathetic and parasympathetic nervous systems. Entrainment also arises between organisms. The harmonizing of coupled oscillators into a single, dominant frequency is called frequency-selective entrainment. We propose that this phenomenon is the modus operandi of practitioners who use the cranial rhythmic impulse in craniosacral treatment. Dominant entrainment is enhanced by "centering," a technique practiced by many healers, for example, practitioners of Chinese, Tibetan, and Ayurvedic medicine. We explore the connections between centering, the cranial rhythmic impulse, and craniosacral treatment.

  3. Particle visualization in high-power impulse magnetron sputtering. II. Absolute density dynamics

    SciTech Connect

    Britun, Nikolay Palmucci, Maria; Konstantinidis, Stephanos; Snyders, Rony

    2015-04-28

    Time-resolved characterization of an Ar-Ti high-power impulse magnetron sputtering discharge has been performed. The present, second, paper of the study is related to the discharge characterization in terms of the absolute density of species using resonant absorption spectroscopy. The results on the time-resolved density evolution of the neutral and singly-ionized Ti ground state atoms as well as the metastable Ti and Ar atoms during the discharge on- and off-time are presented. Among the others, the questions related to the inversion of population of the Ti energy sublevels, as well as to re-normalization of the two-dimensional density maps in terms of the absolute density of species, are stressed.

  4. Anti-reflux surgery - children - discharge

    MedlinePlus

    Fundoplication - children - discharge; Nissen fundoplication - children - discharge; Belsey (Mark IV) fundoplication - children - discharge; Toupet fundoplication - children - discharge; Thal fundoplication - ...

  5. Impulsive Behavior and Associated Clinical Variables in Parkinson's Disease

    PubMed Central

    Abosch, Aviva; Gupte, Akshay; Eberly, Lynn E.; Tuite, Paul J.; Nance, Martha; Grant, Jon E.

    2011-01-01

    Parkinson's disease (PD) is a degenerative brain disorder accompanied by the loss of dopaminergic neurons and the presence of motor and non-motor symptoms. We performed a cross-sectional, questionnaire-based analysis of impulsive behavior in our PD clinic population to assess prevalence and associated characteristics. We found a higher prevalence of impulsive behavior (29.7%) than previously reported, and found multiple, concurrent impulsive behaviors in 26% of subjects reporting impulsive behavior. Our findings contribute to the growing awareness of impulsive behavior in PD, and support the need for longitudinal studies to assess changes in impulsive behaviors in Parkinson's patients. PMID:21300194

  6. Does impulse noise induce vestibular disturbances?

    PubMed

    Pyykkö, I; Aalto, H; Ylikoski, J

    1989-01-01

    The effect of impulse noise on postural stability was evaluated in 54 subjects from the Finnish army, who were suffering from acute hearing loss caused by exposure to firearms noise. For referents we used 20 non-exposed army recruits and 39 civilian volunteers. The effects of vision, pressoreceptor function and proprioception were stepwise excluded or altered, leaving mainly the vestibular guidance of postural control intact. Since the postural perturbation was fairly smooth during these instances we assume that the condition evaluates mainly the function of the otolith organs in guiding stance. We found no difference in any of the test conditions used, between normal controls, army controls and impulse noise exposed subjects. Furthermore, there was no dose response with body sway and severity of hearing loss. The results indicate that impulse noise may not be the cause of significant functional changes in the vestibular system that can account for noise-induced postural instability.

  7. Auto-programmable impulse neural circuits

    NASA Technical Reports Server (NTRS)

    Watula, D.; Meador, J.

    1990-01-01

    Impulse neural networks use pulse trains to communicate neuron activation levels. Impulse neural circuits emulate natural neurons at a more detailed level than that typically employed by contemporary neural network implementation methods. An impulse neural circuit which realizes short term memory dynamics is presented. The operation of that circuit is then characterized in terms of pulse frequency modulated signals. Both fixed and programmable synapse circuits for realizing long term memory are also described. The implementation of a simple and useful unsupervised learning law is then presented. The implementation of a differential Hebbian learning rule for a specific mean-frequency signal interpretation is shown to have a straightforward implementation using digital combinational logic with a variation of a previously developed programmable synapse circuit. This circuit is expected to be exploited for simple and straightforward implementation of future auto-adaptive neural circuits.

  8. Reflective and impulsive determinants of social behavior.

    PubMed

    Strack, Fritz; Deutsch, Roland

    2004-01-01

    This article describes a 2-systems model that explains social behavior as a joint function of reflective and impulsive processes. In particular, it is assumed that social behavior is controlled by 2 interacting systems that follow different operating principles. The reflective system generates behavioral decisions that are based on knowledge about facts and values, whereas the impulsive system elicits behavior through associative links and motivational orientations. The proposed model describes how the 2 systems interact at various stages of processing, and how their outputs may determine behavior in a synergistic or antagonistic fashion. It extends previous models by integrating motivational components that allow more precise predictions of behavior. The implications of this reflective-impulsive model are applied to various phenomena from social psychology and beyond. Extending previous dual-process accounts, this model is not limited to specific domains of mental functioning and attempts to integrate cognitive, motivational, and behavioral mechanisms.

  9. Impulsive-compulsive buying disorder: clinical overview.

    PubMed

    Dell'Osso, Bernardo; Allen, Andrea; Altamura, A Carlo; Buoli, Massimiliano; Hollander, Eric

    2008-04-01

    Impulsive-compulsive buying disorder (ICBD) is an impulse control disorder not otherwise specified (ICD-NOS) characterized by impulsive drives and compulsive behaviours (buying unneeded things), personal distress, impaired social and vocational functioning and financial problems. Despite being described in the 19th century, serious attention to ICBD began only in the last decade with the first epidemiological and pharmacological investigation. Biological, social and psychological factors contribute to the aetiology of ICBD. Cognitive-behavioural therapy and selective serotonin re-uptake inhibitors are currently considered the more effective interventions in the treatment of ICBD. The present review aims to provide a broad overview of the epidemiology, aetiology, phenomenology and treatment options of ICBD.

  10. Discharge stabilization studies of CO laser gas mixtures in quasi-steady supersonic flow

    NASA Technical Reports Server (NTRS)

    Srinivasan, G.; Smith, J. A.

    1976-01-01

    Experiments were conducted to study the applicability of a double discharge stabilization scheme in conditions appropriate for high energy CO lasers in supersonic flows. A Ludwieg tube impulse flow facility and a ballasted capacitor bank provided essentially steady flow and discharge conditions (d.c.) for times longer than ten electrode length-flow transit times. Steady, arc-free, volume discharges were produced in a Mach 3 test cavity using an auxiliary discharge to stabilize the main discharge in N2 and He/CO mixture. A signigicant result is the lack of observed plasma E/N changes in response to auxiliary discharge current changes. Also, where glow discharges were obtained, the energy loading achieved was very much less than the threshold level required for laser operation.

  11. Associations between regional brain physiology and trait impulsivity, motor inhibition, and impaired control over drinking

    PubMed Central

    Weafer, Jessica; Dzemidzic, Mario; Eiler, William; Oberlin, Brandon G.; Wang, Yang; Kareken, David A.

    2015-01-01

    Trait impulsivity and poor inhibitory control are well-established risk factors for alcohol misuse, yet little is known about the associated neurobiological endophenotypes. Here we examined correlations among brain physiology and self-reported trait impulsive behavior, impaired control over drinking, and a behavioral measure of response inhibition. A sample of healthy drinkers (n=117) completed a pulsed arterial spin labeling (PASL) scan to quantify resting regional cerebral blood flow (rCBF), and measures of self-reported impulsivity (Eysenck I7 Impulsivity scale) and impaired control over drinking. A subset of subjects (n=40) performed a stop signal task during blood oxygenation level-dependent (BOLD) functional magnetic resonance imaging to assess brain regions involved in response inhibition. Eysenck I7 scores were inversely related to blood flow in the right precentral gyrus. Significant BOLD activation during response inhibition occurred in an overlapping right frontal motor/premotor region. Moreover, impaired control over drinking was associated with reduced BOLD response in the same region. These findings suggest that impulsive personality and impaired control over drinking are associated with brain physiology in areas implicated in response inhibition. This is consistent with the idea that difficulty controlling behavior is due in part to impairment in motor restraint systems. PMID:26065376

  12. Out of control: Evidence for anterior insula involvement in motor impulsivity and reactive aggression

    PubMed Central

    Sack, Alexander T.; Lobbestael, Jill; Arntz, Arnoud; Brugman, Suzanne; Schuhmann, Teresa

    2015-01-01

    Inhibiting impulsive reactions while still defending one’s vital resources is paramount to functional self-control and successful development in a social environment. However, this ability of successfully inhibiting, and thus controlling one’s impulsivity, often fails, leading to consequences ranging from motor impulsivity to aggressive reactions following provocation. Although inhibitory failure represents the underlying mechanism, the neurocognition of social aggression and motor response inhibition have traditionally been investigated in separation. Here, we aimed to directly investigate and compare the neural mechanisms underlying the failure of inhibition across those different modalities of self-control. We used functional imaging to reveal the overlap in neural correlates between failed motor response inhibition (measured by a go/no-go task) and reactive aggression (measured by the Taylor aggression paradigm) in healthy males. The core overlap of neural correlates was located in the anterior insula, suggesting common anterior insula involvement in motor impulsivity as well as reactive aggression. This evidence regarding an overarching role of the anterior insula across different modalities of self-control enables an integrative perspective on insula function and a better integration of cognitive, social and emotional factors into a comprehensive model of impulsivity. Furthermore, it can eventually lead to a better understanding of clinical syndromes involving inhibitory deficits. PMID:24837479

  13. Model-free functional connectivity and impulsivity correlates of alcohol dependence: a resting-state study.

    PubMed

    Zhu, Xi; Cortes, Carlos R; Mathur, Karan; Tomasi, Dardo; Momenan, Reza

    2017-01-01

    Alcohol dependence is characterized by impulsiveness toward consumption despite negative consequences. Although neuro-imaging studies have implicated some regions underlying this disorder, there is little information regarding its large-scale connectivity pattern. This study investigated the within- and between-network functional connectivity (FC) in alcohol dependence and examined its relationship with clinical impulsivity measures. Using probabilistic independent component analysis on resting-state functional magnetic resonance imaging (rs-fMRI) data from 25 alcohol-dependent (AD) and 26 healthy control (HC) participants, we compared the within- and between-network FC between AD and HC. Then, the relationship between FC and impulsiveness as measured by the Barratt Impulsiveness Scale (BIS-11), the UPPS-P Impulsive Scale and the delay discounting task (DDT), was explored. Compared with HC, AD exhibited increased within-network FC in salience (SN), default mode (DMN), orbitofrontal cortex (OFCN), left executive control (LECN) and amygdala-striatum (ASN) networks. Increased between-network FC was found among LECN, ASN and SN. Between-network FC correlations were significantly negative between Negative-Urgency and OFCN pairs with right executive control network (RECN), anterior DMN (a-DMN) and posterior DMN (p-DMN) in AD. DDT was significantly correlated with the between-network FC among the LECN, a-DMN and SN in AD. These findings add evidence to the concept of altered within-network FC and also highlight the role of between-network FC in the pathophysiology of AD. Additionally, this study suggests differential neurobiological bases for different clinical measures of impulsivity that may be used as a systems-level biomarker for alcohol dependence severity and treatment efficacy.

  14. [Prolonged homosynaptic depression of the impulse reactions of the motor cortex neurons in the cat].

    PubMed

    Sil'kis, I G; Rapoport, S Sh; Veber, N V; Gushchin, A M

    1993-01-01

    It is shown that in the motor and the visual cortices of the cat the homosynaptic long-term posttetanic depression (LTD) of monosynaptic impulse responses of the cortical neurons may be induced in the tetanized input. Homosynaptic LTD appears as a decrease of the probability of the monosynaptic discharges or an increase in the latency of the monosynaptic responses. The cortical homosynaptic depression possesses the same properties as the hippocampal LTD, namely, the longevity, input specificity, cooperativity, and associativity. The possible mechanisms of the homosynaptic LTD induction are discussed. The effect may be determined, on the one hand, as Ca-dependent phenomenon, and on the other hand, as the LTP of monosynaptic reactions of the input inhibitory interneurons. It is supposed that the homosynaptic LTD of the impulse reactions of the cortical neurons may be one of the basic mechanisms in certain learning tasks, such as habituation or extinction.

  15. Self-pulsing in a low-current hollow cathode discharge: From Townsend to glow discharge

    SciTech Connect

    Qin, Yu; Xie, Kan; Zhang, Yu; Ouyang, Jiting

    2016-02-15

    We investigate the self-pulsing phenomenon of a low current cavity discharge in a cylindrical hollow cathode in pure argon. The waveforms of pulsed current and voltage are measured, and the time-averaged and time-resolved images of hollow cathode discharge are recorded by using high-speed intensified charge coupled device camera. The results show that the self-pulsing is a mode transition between low-current stage of Townsend discharge and high-current stage of glow discharge. During the self-pulsing, the current rising time relates to the dissipation of space charges, and the decay time relates to the reconstruction of the virtual anode by the accumulation of positive ions. Whether or not space charges can form and keep the virtual anode is responsible for the discharge mode and hence plays an important role in the self-pulsing phenomenon in low current hollow cathode discharge.

  16. fMRI investigation of response inhibition, emotion, impulsivity, and clinical high-risk behavior in adolescents

    PubMed Central

    Brown, Matthew R. G.; Benoit, James R. A.; Juhás, Michal; Dametto, Ericson; Tse, Tiffanie T.; MacKay, Marnie; Sen, Bhaskar; Carroll, Alan M.; Hodlevskyy, Oleksandr; Silverstone, Peter H.; Dolcos, Florin; Dursun, Serdar M.; Greenshaw, Andrew J.

    2015-01-01

    High-risk behavior in adolescents is associated with injury, mental health problems, and poor outcomes in later life. Improved understanding of the neurobiology of high-risk behavior and impulsivity shows promise for informing clinical treatment and prevention as well as policy to better address high-risk behavior. We recruited 21 adolescents (age 14–17) with a wide range of high-risk behavior tendencies, including medically high-risk participants recruited from psychiatric clinics. Risk tendencies were assessed using the Adolescent Risk Behavior Screen (ARBS). ARBS risk scores correlated highly (0.78) with impulsivity scores from the Barratt Impulsivity scale (BIS). Participants underwent 4.7 Tesla functional magnetic resonance imaging (fMRI) while performing an emotional Go/NoGo task. This task presented an aversive or neutral distractor image simultaneously with each Go or NoGo stimulus. Risk behavior and impulsivity tendencies exhibited similar but not identical associations with fMRI activation patterns in prefrontal brain regions. We interpret these results as reflecting differences in response inhibition, emotional stimulus processing, and emotion regulation in relation to participant risk behavior tendencies and impulsivity levels. The results are consistent with high impulsivity playing an important role in determining high risk tendencies in this sample containing clinically high-risk adolescents. PMID:26483645

  17. Dimensions of impulsive behavior in adolescents: laboratory behavioral assessments.

    PubMed

    Reynolds, Brady; Penfold, Robert B; Patak, Michele

    2008-04-01

    Impulsivity is a multifaceted construct that defines a range of maladaptive behavioral styles. The present research aimed to identify different dimensions of impulsive behavior in adolescents from a battery of laboratory behavioral assessments. In one analysis, correlations were examined between two self report and seven laboratory behavioral measures of impulsivity. The correlation between the two self report measures was high compared to correlations between the self report and laboratory behavioral measures. In a second analysis, a principal components analysis was performed with just the laboratory behavioral measures. Three behavioral dimensions were identified -- "impulsive decision-making", "impulsive inattention", and "impulsive disinhibition". These dimensions were further evaluated using the same sample with a confirmatory factor analysis, which did support the hypothesis that these are significant and independent dimensions of impulsivity. This research indicates there are at least three separate subtypes of impulsive behavior when using laboratory behavioral assessments with adolescent participants.

  18. Empathic deficits and alexithymia in trauma-related impulsive aggression.

    PubMed

    Teten, Andra L; Miller, Lisa A; Bailey, Sara D; Dunn, Nancy Jo; Kent, Thomas A

    2008-01-01

    Our long term interest is to develop a developmental model of impulsive aggression based on a confluence of social, psychological and biological features. This approach incorporates neurobiological research, which has identified language processing deficits as a unique characteristic of impulsive aggressors and extends it to include emotional deficits. As an initial test of this hypothesis, we examined whether empathy and alexithymia were associated with impulsive aggression. Regressions were performed to explore the associations among impaired empathy, alexithymia, impulsive aggression, verbal and physical general aggression. Among impulsive aggressive veterans (n=38) recruited from a VA trauma clinic, alexithymia predicted impulsive aggression and empathic deficits predicted verbal aggression. Neither emotional awareness deficit predicted general physical aggression in this middle-aged sample. Results suggested that empathic deficits were associated with general verbal aggression, but alexithymia was uniquely associated with impulsive aggression. Consideration of alexithymia in impulsive aggression has implications for its etiology, prevention and treatment.

  19. Impulse Plasma In Surface Engineering - a review

    NASA Astrophysics Data System (ADS)

    Zdunek, K.; Nowakowska-Langier, K.; Chodun, R.; Okrasa, S.; Rabinski, M.; Dora, J.; Domanowski, P.; Halarowicz, J.

    2014-11-01

    The article describes the view of the plasma surface engineering, assuming the role of non-thermal energy effects in the synthesis of materials and coatings deposition. In the following study it was underlined that the vapor excitation through the application of an electric field during coatings deposition gives new possibilities for coatings formation. As an example the IPD method was chosen. During the IPD (Impulse Plasma Deposition) the impulse plasma is generated in the coaxial accelerator by strong periodic electrical pulses. The impulse plasma is distributed in the form of energetic plasma pockets. Due to the almost completely ionization of gas, the nucleation of new phases takes place on ions directly in the plasma itself. As a result the coatings of metastable materials with nano-amorphous structure and excellent adhesion to the non-heated intentionally substrates could be deposited. Recently the novel way of impulse plasma generation during the coatings deposition was proposed and developed by our group. An efficient tool for plasma process control, the plasma forming gas injection to the interelectrode space was used. Periodic changing the gas pressure results in increasing both the degree of dispersion and the dynamics of the plasma pulses. The advantage of the new technique in deposition of coatings with exceptionally good properties has been demonstrated in the industrial scale not only in the case of the IPD method but also in the case of very well known magnetron sputtering method.

  20. Functional impulsivity and reinforcement sensitivity theory.

    PubMed

    Smillie, Luke D; Jackson, Chris J

    2006-02-01

    In this article, we attempt to integrate Dickman's (1990) descriptive concept of Functional Impulsivity (FI) with Gray's (1970, 1991) Reinforcement Sensitivity Theory (RST). Specifically, we consider that FI bears great conceptual similarity to Gray's concept of reward-reactivity, which is thought to be caused by the combined effects of a Behavioral Activation System (BAS) and Behavioral Inhibition System (BIS). In our first study, we examine the construct validity and structural correlates of FI. Results indicate that FI is related positively to measures of BAS and Extraversion, negatively to measures of BIS and Neuroticism, and is separate from Psychoticism and typical trait Impulsivity, which Dickman calls Dysfunctional Impulsivity (DI). In our second study, we use a go/no-go discrimination task to examine the relationship between FI and response bias under conditions of rewarding and punishing feedback. Results indicate that FI, along with two measures of BAS, predicted the development of a response bias for the rewarded alternative. In comparison, high DI appeared to reflect indifference toward either reward or punishment. We consider how these findings might reconcile the perspectives of Gray and Dickman and help clarify the broader understanding of Impulsivity.

  1. Impulsive Behaviors in Patients With Pathological Buying

    PubMed Central

    Zander, Heike; Claes, Laurence; Voth, Eva M.; de Zwaan, Martina; Müller, Astrid

    2016-01-01

    Aim To investigate impulsive behaviors in pathological buying (PB). Methods The study included three groups matched for age and gender: treatment seeking outpatients with PB (PB+), treatment seeking psychiatric inpatients without PB (PB−), and a healthy control group (HC). PB was assessed by means of the Compulsive Buying Scale and by the impulse control disorder (ICD) module of the research version of the Structured Clinical Interview for DSM-IV (SCID-ICD). All participants answered questionnaires concerning symptoms of borderline personality disorder, self-harming behaviors, binge eating and symptoms of attention deficit and hyperactivity disorder (ADHD). In addition, comorbid ICDs were assessed using the SCID-ICD. Results The PB+ and PB− groups did not differ with regard to borderline personality disorder or ADHD symptoms, but both groups reported significantly more symptoms than the HC group. Frequencies of self-harming behaviors did not differ between the three groups. Patients with PB were more often diagnosed with any current ICD (excluding PB) compared to those without PB and the HC group (38.7% vs. 12.9% vs. 12.9%, respectively, p=.017). Discussion Our findings confirm prior research suggesting more impulsive behaviors in patients with and without PB compared to healthy controls. The results of the questionnaire-based assessment indicate that outpatients with PB perceive themselves equally impulsive and self-harm as frequently as inpatients without PB; but they seem to suffer more often from an ICD as assessed by means of an interview. PMID:27415604

  2. Specific Impulses Losses in Solid Propellant Rockets

    DTIC Science & Technology

    1974-12-17

    to use the collision function form proposed by Golovin to simplify this production term: 4C><=) <P- .: Accordingly: m hence, by integration: Now, we...November 21, 1940 in Paris, Seine. VFirst Thesis. "Contribution to the Study of Specific i Impulse Loss in Solid Propellant Rockets." Second Thesis

  3. Impulse noise trauma during army weapon firing.

    PubMed

    Munjal, K R; Singh, V P

    1997-04-01

    A 100 infanty personnel firing modern weapons such as the Anti Tank Guided Missile, 106mm Recoiless Gun (RCL), 84mm Rocket Launcher (RL) and 81mm Mortar were studied for the effect of impulse noise on the ear and the evolution of the Temporary Threshold Shift (TTS), Recovery Time (RT) and Permanent Threshold Shift (PTS) was traced.

  4. How Many Impulsivities? A Discounting Perspective

    ERIC Educational Resources Information Center

    Green, Leonard; Myerson, Joel

    2013-01-01

    People discount the value of delayed and uncertain outcomes, and how steeply individuals discount is thought to reflect how impulsive they are. From this perspective, steep discounting of delayed outcomes (which fails to maximize long-term welfare) and shallow discounting of probabilistic outcomes (which fails to adequately take risk into account)…

  5. Maternal Inattention and Impulsivity and Parenting Behaviors

    ERIC Educational Resources Information Center

    Chen, Mandy; Johnston, Charlotte

    2007-01-01

    This study extends previous research by examining whether maternal inattention, impulsivity, and hyperactivity are associated with different parenting behaviors. Ninety-six mother-son dyads participated in the study, and the boys ranged between 4 and 8 years of age. Maternal inattention was uniquely and positively associated with mothers' use of…

  6. The Relationship among Spontaneity, Impulsivity, and Creativity

    ERIC Educational Resources Information Center

    Kipper, David A.; Green, Doreen J.; Prorak, Amanda

    2010-01-01

    The present study was designed to investigate two characteristics of spontaneity, its relationship to creativity and to impulsivity. We hypothesized a positive relationship between spontaneity and creativity, consistent with Moreno, 1953 "canon of spontaneity-creativity." We also predicted a negative relationship between spontaneity and…

  7. A Dual-Polarity Impulse Radiating Antenna

    NASA Astrophysics Data System (ADS)

    Bowen, L. H.; Farr, E. G.; Lawry, D. I.

    Dual polarity Impulse Radiating Antennas (IRA's) may be useful in a variety of applications. The dual-polarity IRA described here has an impendence mismatch for each polarity at the focus of the reflector. In spite of this mismatch the antenna characteristics are quite good up to 10 GHz for applications where reflections within the system are not of great importance.

  8. Impulsivity and Strategy Transfer: Metamemory as Mediator.

    ERIC Educational Resources Information Center

    Borkowski, John G.; And Others

    1983-01-01

    Acquisition, maintenance, and generalization of organizational strategies were studied in two experiments as a function of impulsivity-reflectivity and metamemory among primary school students. Findings are in line with the hypothesis that metamemory, rather than cognitive tempo, mediates the effectiveness of an experimenter-trained strategy in…

  9. Arbitration between controlled and impulsive choices

    PubMed Central

    Economides, M.; Guitart-Masip, M.; Kurth-Nelson, Z.; Dolan, R.J.

    2015-01-01

    The impulse to act for immediate reward often conflicts with more deliberate evaluations that support long-term benefit. The neural architecture that negotiates this conflict remains unclear. One account proposes a single neural circuit that evaluates both immediate and delayed outcomes, while another outlines separate impulsive and patient systems that compete for behavioral control. Here we designed a task in which a complex payout structure divorces the immediate value of acting from the overall long-term value, within the same outcome modality. Using model-based fMRI in humans, we demonstrate separate neural representations of immediate and long-term values, with the former tracked in the anterior caudate (AC) and the latter in the ventromedial prefrontal cortex (vmPFC). Crucially, when subjects' choices were compatible with long-run consequences, value signals in AC were down-weighted and those in vmPFC were enhanced, while the opposite occurred when choice was impulsive. Thus, our data implicate a trade-off in value representation between AC and vmPFC as underlying controlled versus impulsive choice. PMID:25573670

  10. Ultrahigh Specific Impulse Nuclear Thermal Propulsion

    SciTech Connect

    Anne Charmeau; Brandon Cunningham; Samim Anghaie

    2009-02-09

    Research on nuclear thermal propulsion systems (NTP) have been in forefront of the space nuclear power and propulsion due to their design simplicity and their promise for providing very high thrust at reasonably high specific impulse. During NERVA-ROVER program in late 1950's till early 1970's, the United States developed and ground tested about 18 NTP systems without ever deploying them into space. The NERVA-ROVER program included development and testing of NTP systems with very high thrust (~250,000 lbf) and relatively high specific impulse (~850 s). High thrust to weight ratio in NTP systems is an indicator of high acceleration that could be achieved with these systems. The specific impulse in the lowest mass propellant, hydrogen, is a function of square root of absolute temperature in the NTP thrust chamber. Therefor optimizing design performance of NTP systems would require achieving the highest possible hydrogen temperature at reasonably high thrust to weight ratio. High hydrogen exit temperature produces high specific impulse that is a diret measure of propellant usage efficiency.

  11. The Formation and Transformation of Moral Impulse.

    ERIC Educational Resources Information Center

    Zigler, Ronald Lee

    1999-01-01

    Examines recent research that suggests the formation of moral impulse, rather than moral reasoning, is the basis for moral development and education. Discusses the insights of the medieval Jewish philosopher and physician Maimonides, comparing his ideas with current research in neuroscience. Discusses implications for educational and social…

  12. Initial formation of an "impulsive" coronal mass ejection

    NASA Astrophysics Data System (ADS)

    Eselevich, V. G.; Eselevich, M. V.; Zimovets, I. V.; Rudenko, G. V.

    2016-11-01

    An "impulsive" coronal mass ejection (CME) observed on August 24, 2014 is analyzed using ultraviolet images obtained in the SDO/AIA 193, 304, 1600, and 1700 Å channels and H α (6562.8 Å) data obtained with the EI Teide and Big Bear telescopes. The formation of this impulsive CME was related to a magnetic tube (rope) moving with a velocity of ≈35 km/s and containing plasma that was cooler than the photospheric material. Moving in the corona, the magnetic tube collides with a quasi-stationary coronal magnetic rope, with its two bases rooted in the photosphere. This interaction results in the formation of the CME, with the surface of the coronal magnetic rope becoming the CME frontal structure. According to SDO/HMI data, no enhancements or changes in magnetic flux were detected in the vicinity of the CME bases during its formation. This may support the hypothesis that the magnetic tube starts its motion from layers in the vicinity of the temperature minimum.

  13. The Pathophysiology of Impulse control Disorders in Parkinson Disease

    PubMed Central

    Balarajah, Sharmili; Cavanna, Andrea Eugenio

    2013-01-01

    Aims: This review aims to evaluate the most recent evidence on the pathophysiology of impulse control disorders (ICDs) in Parkinson disease (PD). Methods: Computerised searches of Medline, Embase and PsycInfo, along with manual searches for grey literature, were conducted and resulted in a total of 16 studies suitable for review. Results: Evidence was divided into four categories: medication used in PD management, imaging studies, genetic analysis and subthalamic deep brain stimulation (STN-DBS). Analysis of the literature reveals that both intrinsic and extrinsic factors may play a role in the pathophysiology of ICDs in PD. Dysfunction of the mesocorticolimbic pathway and polymorphisms of the dopamine D3 and D4 receptors may increase an individual's susceptibility to the development of ICDs. Discussion: Dopaminergic medication, particularly dopamine agonists (DAs), increases the risk of developing impulsive behaviours in a PD patient. Further evidence, particularly in the form of prospective studies and randomised controlled trials is required to better establish the pathophysiology of ICDs in PD. PMID:22713408

  14. THE EMISSION MEASURE DISTRIBUTION OF IMPULSIVE PHASE FLARE FOOTPOINTS

    SciTech Connect

    Graham, D. R.; Hannah, I. G.; Fletcher, L.; Milligan, R. O.

    2013-04-10

    The temperature distribution of the emitting plasma is a crucial constraint when studying the heating of solar flare footpoints. However, determining this for impulsive phase footpoints has been difficult in the past due to insufficient spatial resolution to resolve the footpoints from the loop structures, and a lack of spectral and temporal coverage. We use the capabilities of Hinode/Extreme Ultraviolet Imaging Spectrometer to obtain the first emission measure distributions (EMDs) from impulsive phase footpoints in six flares. Observations with good spectral coverage were analyzed using a regularized inversion method to recover the EMDs. We find that the EMDs all share a peak temperature of around 8 MK, with lines formed around this temperature having emission measures (EMs) peaking between 10{sup 28} and 10{sup 29} cm{sup -5}, indicating a substantial presence of plasma at very high temperatures within the footpoints. An EMD gradient of EM(T) {approx} T is found in all events. Previous theoretical work on EM gradients shows this to be consistent with a scenario in which the deposited flare energy directly heats only the top layer of the flare chromosphere, while deeper layers are heated by conduction.

  15. Electrophysiology of the insect dorsal ocellus. II. Mechanisms of generation and inhibition of impulses in the ocellar nerve of dragonflies.

    PubMed

    RUCK, P

    1961-01-01

    Large nerve fibers in the ocellar nerves of dragonflies are spontaneously active. In the absence of inhibitory influence the spontaneous activity is rhythmic. Inhibition occurs in the dark-adapted state and during illumination. Miniature inhibitory postsynaptic potentials occur in the dark-adapted state. These modulate by temporary suppression the otherwise rhythmic discharge of ocellar nerve impulses. The presence of random spontaneous receptor cell excitations is inferred from the presence of the miniature i.p.s.p.'s. Light stimulates many or all the receptor cells simultaneously, masking the random spontaneous activity of individual receptor cells. The result is a sustained hyperpolarizing i.p.s.p. and sustained inhibition of the nerve discharge. Preceding resumption of the spontaneous activity at "off" the i.p.s.p. may oscillate, overshoot the baseline as a negative after-potential, or do both. These phases of the off-effect may generate nerve impulses in an off-burst.

  16. Pelvic radiation - discharge

    MedlinePlus

    Radiation of the pelvis - discharge; Cancer treatment - pelvic radiation; Prostate cancer - pelvic radiation; Ovarian cancer - pelvic radiation; Cervical cancer - pelvic radiation; Uterine cancer - pelvic radiation; Rectal cancer - ...

  17. Fractionating impulsivity: contrasting effects of central 5-HT depletion on different measures of impulsive behavior.

    PubMed

    Winstanley, Catharine A; Dalley, Jeffrey W; Theobald, David E H; Robbins, Trevor W

    2004-07-01

    Reducing levels of 5-HT in the central nervous system has been associated with increases in impulsive behavior. However, the impulsivity construct describes a wide range of behaviors, including the inability to withhold a response, intolerance to delay of reward and perseveration of a nonrewarded response. Although these behaviors are generally studied using instrumental paradigms, impulsivity may also be reflected in simple Pavlovian tasks such as autoshaping and conditioned activity. This experiment aimed to characterize further the effects of central 5-HT depletion and to investigate whether different behavioral measures of impulsivity are inter-related, thus validating the construct. Rats received intracerebroventricular (ICV) infusions of vehicle (n=10) or the serotonergic neurotoxin 5,7-dihydroxytryptamine (n=12) which depleted forebrain 5-HT levels by about 90%. Lesioned animals showed significant increases in the speed and number of responses made in autoshaping, increased premature responding on a simple visual attentional task, enhanced expression of locomotor activity conditioned to food presentation, yet no change in impulsive choice was observed, as measured by a delay-discounting paradigm. Significant positive correlations were found between responses made in autoshaping and the level of conditioned activity, indicating a possible common basis for these behaviors, yet no correlations were found between other behavioral measures. These data strengthen and extend the hypothesis that 5-HT depletion increases certain types of impulsive responding. However, not all measures of impulsivity appear to be uniformly affected by 5-HT depletion, or correlate with each other, supporting the suggestion that impulsivity is not a unitary construct.

  18. The flare kernel in the impulsive phase

    NASA Technical Reports Server (NTRS)

    Dejager, C.

    1986-01-01

    The impulsive phase of a flare is characterized by impulsive bursts of X-ray and microwave radiation, related to impulsive footpoint heating up to 50 or 60 MK, by upward gas velocities (150 to 400 km/sec) and by a gradual increase of the flare's thermal energy content. These phenomena, as well as non-thermal effects, are all related to the impulsive energy injection into the flare. The available observations are also quantitatively consistent with a model in which energy is injected into the flare by beams of energetic electrons, causing ablation of chromospheric gas, followed by convective rise of gas. Thus, a hole is burned into the chromosphere; at the end of impulsive phase of an average flare the lower part of that hole is situated about 1800 km above the photosphere. H alpha and other optical and UV line emission is radiated by a thin layer (approx. 20 km) at the bottom of the flare kernel. The upward rising and outward streaming gas cools down by conduction in about 45 s. The non-thermal effects in the initial phase are due to curtailing of the energy distribution function by escape of energetic electrons. The single flux tube model of a flare does not fit with these observations; instead we propose the spaghetti-bundle model. Microwave and gamma-ray observations suggest the occurrence of dense flare knots of approx. 800 km diameter, and of high temperature. Future observations should concentrate on locating the microwave/gamma-ray sources, and on determining the kernel's fine structure and the related multi-loop structure of the flaring area.

  19. Practical stability analysis of fractional-order impulsive control systems.

    PubMed

    Stamova, Ivanka; Henderson, Johnny

    2016-09-01

    In this paper we obtain sufficient conditions for practical stability of a nonlinear system of differential equations of fractional order subject to impulse effects. Our results provide a design method of impulsive control law which practically stabilizes the impulse free fractional-order system.

  20. Measuring Impulsivity in Adolescents with Serious Substance and Conduct Problems

    ERIC Educational Resources Information Center

    Thompson, Laetitia L.; Whitmore, Elizabeth A.; Raymond, Kristen M.; Crowley, Thomas J.

    2006-01-01

    Adolescents with substance use and conduct disorders have high rates of aggression and attention deficit hyperactivity disorder (ADHD), all of which have been characterized in part by impulsivity. Developing measures that capture impulsivity behaviorally and correlate with self-reported impulsivity has been difficult. One promising behavioral…

  1. Recursive Inversion By Finite-Impulse-Response Filters

    NASA Technical Reports Server (NTRS)

    Bach, Ralph E., Jr.; Baram, Yoram

    1991-01-01

    Recursive approximation gives least-squares best fit to exact response. Algorithm yields finite-impulse-response approximation of unknown single-input/single-output, causal, time-invariant, linear, real system, response of which is sequence of impulses. Applicable to such system-inversion problems as suppression of echoes and identification of target from its scatter response to incident impulse.

  2. Impulsive for life? The nature of long-term impulsivity in domestic dogs.

    PubMed

    Riemer, Stefanie; Mills, Daniel S; Wright, Hannah

    2014-05-01

    Individual differences in impulsivity occur at a cognitive and/or behavioural level and are associated with differing life outcomes. However, there is a lack of empirical evidence to support the long-term stability of these characteristics in non-human animals. This study reports on the stability of convergent measures of impulsivity in domestic dogs assessed more than 6 years apart. Measures were (1) owner assessment by means of a questionnaire, the validated 'Dog Impulsivity Assessment Scale' (DIAS) and (2) dogs' performance in a delayed reward choice test. Dogs had 15-min free access to two food dispensers, one dispensing a piece of food immediately, the other dispensing three pieces after a delay, which increased by 1 s every other time the dogs sampled it. Maximum delay reached in this task reflects decision-making, or cognitive impulsivity, whereas the rate of extra presses on the delayed reward device during the delay can be considered as a measure of motor or behavioural impulsivity. DIAS scores were strongly and significantly correlated across years. The maximum delay reached in the behaviour test was also highly stable, whereas paw-pressing rate was uncorrelated between the years. These results demonstrate that cognitive but not motor impulsivity is highly consistent over time in dogs.

  3. An enantiomorphic blumlein impulse generator

    SciTech Connect

    Rinehart, L.F.; Buttram, M.T.; Crowe, W.R.; Clark, R.S.; Lundstrom, J.M.; Patterson, P.E.

    1992-07-01

    Working designs exist for 1 GW, 1 kHz ultra-wideband (UWB) sources (e.g. SNIPER). As these generators are pressed to higher peak powers and repetition rates, insulation, energy loss due to stray capacitance, and system efficiency (including power supplies and modulators) become critical issues. The EnantioMorphic (mirror image) BLumlein (EMBL) is a new type of vector inversion transmission line pulser which is designed to alleviate some of these problems. The design goals for EMBL are : >500 kV, {approximately}1 kHz rep-rate and <100 ps risetime in a 50 ohm geometry. In addition to the pulse forming line (PFL), EMBL also requires a high rep-rate modulator, primary switch, and peaking switch which will be described. Empirical design equations for peaking switch performance are included.

  4. An enantiomorphic blumlein impulse generator

    SciTech Connect

    Rinehart, L.F.; Buttram, M.T.; Crowe, W.R.; Clark, R.S.; Lundstrom, J.M.; Patterson, P.E.

    1992-01-01

    Working designs exist for 1 GW, 1 kHz ultra-wideband (UWB) sources (e.g. SNIPER). As these generators are pressed to higher peak powers and repetition rates, insulation, energy loss due to stray capacitance, and system efficiency (including power supplies and modulators) become critical issues. The EnantioMorphic (mirror image) BLumlein (EMBL) is a new type of vector inversion transmission line pulser which is designed to alleviate some of these problems. The design goals for EMBL are : >500 kV, {approximately}1 kHz rep-rate and <100 ps risetime in a 50 ohm geometry. In addition to the pulse forming line (PFL), EMBL also requires a high rep-rate modulator, primary switch, and peaking switch which will be described. Empirical design equations for peaking switch performance are included.

  5. The Stomach-Derived Hormone Ghrelin Increases Impulsive Behavior.

    PubMed

    Anderberg, Rozita H; Hansson, Caroline; Fenander, Maya; Richard, Jennifer E; Dickson, Suzanne L; Nissbrandt, Hans; Bergquist, Filip; Skibicka, Karolina P

    2016-04-01

    Impulsivity, defined as impaired decision making, is associated with many psychiatric and behavioral disorders, such as attention-deficit/hyperactivity disorder as well as eating disorders. Recent data indicate that there is a strong positive correlation between food reward behavior and impulsivity, but the mechanisms behind this relationship remain unknown. Here we hypothesize that ghrelin, an orexigenic hormone produced by the stomach and known to increase food reward behavior, also increases impulsivity. In order to assess the impact of ghrelin on impulsivity, rats were trained in three complementary tests of impulsive behavior and choice: differential reinforcement of low rate (DRL), go/no-go, and delay discounting. Ghrelin injection into the lateral ventricle increased impulsive behavior, as indicated by reduced efficiency of performance in the DRL test, and increased lever pressing during the no-go periods of the go/no-go test. Central ghrelin stimulation also increased impulsive choice, as evidenced by the reduced choice for large rewards when delivered with a delay in the delay discounting test. In order to determine whether signaling at the central ghrelin receptors is necessary for maintenance of normal levels of impulsive behavior, DRL performance was assessed following ghrelin receptor blockade with central infusion of a ghrelin receptor antagonist. Central ghrelin receptor blockade reduced impulsive behavior, as reflected by increased efficiency of performance in the DRL task. To further investigate the neurobiological substrate underlying the impulsivity effect of ghrelin, we microinjected ghrelin into the ventral tegmental area, an area harboring dopaminergic cell bodies. Ghrelin receptor stimulation within the VTA was sufficient to increase impulsive behavior. We further evaluated the impact of ghrelin on dopamine-related gene expression and dopamine turnover in brain areas key in impulsive behavior control. This study provides the first

  6. Plasma reactivity in high-power impulse magnetron sputtering through oxygen kinetics

    SciTech Connect

    Vitelaru, Catalin; Lundin, Daniel; Brenning, Nils; Minea, Tiberiu

    2013-09-02

    The atomic oxygen metastable dynamics in a Reactive High-Power Impulse Magnetron Sputtering (R-HiPIMS) discharge has been characterized using time-resolved diode laser absorption in an Ar/O{sub 2} gas mixture with a Ti target. Two plasma regions are identified: the ionization region (IR) close to the target and further out the diffusion region (DR), separated by a transition region. The μs temporal resolution allows identifying the main atomic oxygen production and destruction routes, which are found to be very different during the pulse as compared to the afterglow as deduced from their evolution in space and time.

  7. Simple method of determining plasma impedance of streamer discharge in atmospheric air.

    PubMed

    Okano, Daisuke

    2011-12-01

    For atmospheric streamer discharges using a lightning impulse generator, we demonstrate a method of determining the plasma impedance in a streamer region by analyzing the periodic attenuated discharge waveforms having high-frequency components. When the streamer region in the plasma can be treated as an equivalent series circuit model including resistance and inductance elements, the regression waveforms obtained by reducing and smoothing the discharge waveforms are analyzed in the equivalent circuit. We found that the streamer resistance increased exponentially with time after the discharge, whereas the streamer inductance and series impedance were constant at 4.0 Ω for longer than the first period of the discharge waveforms. Moreover, the slope of the regression curve increases more rapidly for the positive streamer resistance than for the negative resistance. Finally, the absolute values of the streamer impedance versus time were 3.3-19 Ω and 3.5-9.0 Ω for positive and negative discharges, respectively.

  8. Statistical Evidence Suggests that Inattention Drives Hyperactivity/Impulsivity in Attention Deficit-Hyperactivity Disorder

    PubMed Central

    Sokolova, Elena; Groot, Perry; Claassen, Tom; van Hulzen, Kimm J.; Glennon, Jeffrey C.; Franke, Barbara

    2016-01-01

    Background Numerous factor analytic studies consistently support a distinction between two symptom domains of attention-deficit/hyperactivity disorder (ADHD), inattention and hyperactivity/impulsivity. Both dimensions show high internal consistency and moderate to strong correlations with each other. However, it is not clear what drives this strong correlation. The aim of this paper is to address this issue. Method We applied a sophisticated approach for causal discovery on three independent data sets of scores of the two ADHD dimensions in NeuroIMAGE (total N = 675), ADHD-200 (N = 245), and IMpACT (N = 164), assessed by different raters and instruments, and further used information on gender or a genetic risk haplotype. Results In all data sets we found strong statistical evidence for the same pattern: the clear dependence between hyperactivity/impulsivity symptom level and an established genetic factor (either gender or risk haplotype) vanishes when one conditions upon inattention symptom level. Under reasonable assumptions, e.g., that phenotypes do not cause genotypes, a causal model that is consistent with this pattern contains a causal path from inattention to hyperactivity/impulsivity. Conclusions The robust dependency cancellation observed in three different data sets suggests that inattention is a driving factor for hyperactivity/impulsivity. This causal hypothesis can be further validated in intervention studies. Our model suggests that interventions that affect inattention will also have an effect on the level of hyperactivity/impulsivity. On the other hand, interventions that affect hyperactivity/impulsivity would not change the level of inattention. This causal model may explain earlier findings on heritable factors causing ADHD reported in the study of twins with learning difficulties. PMID:27768717

  9. Alterations in Brain Structure and Functional Connectivity in Alcohol Dependent Patients and Possible Association with Impulsivity

    PubMed Central

    Dong, Yue; Ma, Mengying; Ma, Yi; Dong, Yuru; Niu, Yajuan; Jiang, Yin; Wang, Hong; Wang, Zhiyan; Wu, Liuzhen; Sun, Hongqiang; Cui, Cailian

    2016-01-01

    Background Previous studies have documented that heightened impulsivity likely contributes to the development and maintenance of alcohol use disorders. However, there is still a lack of studies that comprehensively detected the brain changes associated with abnormal impulsivity in alcohol addicts. This study was designed to investigate the alterations in brain structure and functional connectivity associated with abnormal impulsivity in alcohol dependent patients. Methods Brain structural and functional magnetic resonance imaging data as well as impulsive behavior data were collected from 20 alcohol dependent patients and 20 age- and sex-matched healthy controls respectively. Voxel-based morphometry was used to investigate the differences of grey matter volume, and tract-based spatial statistics was used to detect abnormal white matter regions between alcohol dependent patients and healthy controls. The alterations in resting-state functional connectivity in alcohol dependent patients were examined using selected brain areas with gray matter deficits as seed regions. Results Compared with healthy controls, alcohol dependent patients had significantly reduced gray matter volume in the mesocorticolimbic system including the dorsal posterior cingulate cortex, the dorsal anterior cingulate cortex, the medial prefrontal cortex, the orbitofrontal cortex and the putamen, decreased fractional anisotropy in the regions connecting the damaged grey matter areas driven by higher radial diffusivity value in the same areas and decreased resting-state functional connectivity within the reward network. Moreover, the gray matter volume of the left medial prefrontal cortex exhibited negative correlations with various impulse indices. Conclusions These findings suggest that chronic alcohol dependence could cause a complex neural changes linked to abnormal impulsivity. PMID:27575491

  10. Graywater Discharges from Vessels

    DTIC Science & Technology

    2011-11-01

    of members is 55; however, two have holding tanks and discharge shore-side and a third vessel is the car ferry Badger that discharges shore-side...Alaskan waters, and in numerous European ports such as Venice and Oslo ever since 2003. Model Capacitiy Load Installed Power

  11. Lithium battery discharge tests

    NASA Technical Reports Server (NTRS)

    Johnson, C. J.

    1980-01-01

    The long term discharge of a variety of lithium cells was characterized and the susceptibility of the cells to chemical variation during the slow discharge was tested. A shunt resistor was set across the terminals to monitor the voltage as a function of time. Failures were identified by premature voltage drops.

  12. Longitudinal discharge laser electrodes

    DOEpatents

    Warner, B.E.; Miller, J.L.; Ault, E.R.

    1994-08-23

    The improved longitudinal discharge laser electrode with IR baffle includes an electrode made up of washers spaced along the laser axis in order to form inter-washer spaces for hollow cathode discharge to take place and for IR radiation to be trapped. Additional IR baffles can be placed between the electrode ann the window. 2 figs.

  13. Longitudinal discharge laser electrodes

    DOEpatents

    Warner, Bruce E.; Miller, John L.; Ault, Earl R.

    1994-01-01

    The improved longitudinal discharge laser electrode with IR baffle includes an electrode made up of washers spaced along the laser axis in order to form inter-washer spaces for hollow cathode discharge to take place and for IR radiation to be trapped. Additional IR baffles can be placed between the electrode ann the window.

  14. Co-axial discharges

    DOEpatents

    Luce, J. S.; Smith, L. P.

    1960-11-22

    An apparatus is described for producing coaxial arc discharges in an evacuated enclosure and within a strong, confining magnetic field. The arcs are maintained at a high potential difference. Electrons diffuse to the more positive arc from the negative arc, and positive ions diffuse from the more positive arc to the negative arc. Coaxial arc discharges have the advantuge that ions that return to strike the positive arc discharge will lose no energy since they do not strike a solid wall or electrode. These discharges are useful in confining an ionized plasma between the discharges and have the advantage of preventing impurities from the walls of the enclosure from entering the plasma area because of the arc barrier set up by the cylindrical outer arc. (auth)

  15. CO-AXIAL DISCHARGES

    DOEpatents

    Luce, J.S.; Smith, L.P.

    1960-11-22

    A method and apparatus are given for producing coaxial arc discharges in an evacuated enclosure and within a strong, confining magnetic field. The arcs are maintained at a high potential difference. Electrons will diffuse to the more positive arc from the negative arc, and positive ions will diffuse from the more positive arc to the negative arc. Coaxial arc discharges have the advantage that ions which return to strike the positive arc discharge will lose no energy since they do not strike a solid wall or electrode. Those discharges are useful in confining an ionized plasma between the discharges, and have the advantage of preventing impurities from the walls of the enclosure from entering ihe plasma area because of the arc barrier set up bv the cylindrical outer arc.

  16. GAS DISCHARGE DEVICES

    DOEpatents

    Jefferson, S.

    1958-11-11

    An apparatus utilized in introducing tritium gas into envelope of a gas discharge device for the purpose f maintaining the discharge path in ionized condition is described. ln addition to the cathode and anode, the ischarge device contains a zirconium or tantalum ilament arranged for external excitation and a metallic seed containing tritium, and also arranged to have a current passed through it. Initially, the zirconium or tantalum filament is vaporized to deposit its material adjacent the main discharge region. Then the tritium gas is released and, due to its affinity for the first released material, it deposits in the region of the main discharge where it is most effective in maintaining the discharge path in an ionized condition.

  17. HOLLOW CARBON ARC DISCHARGE

    DOEpatents

    Luce, J.S.

    1960-10-11

    A device is described for producing an energetic, direct current, hollow, carbon-arc discharge in an evacuated container and within a strong magnetic field. Such discharges are particularly useful not only in dissociation and ionization of high energy molecular ion beams, but also in acting as a shield or barrier against the instreaming of lowenergy neutral particles into a plasma formed within the hollow discharge when it is used as a dissociating mechanism for forming the plasma. There is maintained a predetermined ratio of gas particles to carbon particles released from the arc electrodes during operation of the discharge. The carbon particles absorb some of the gas particles and are pumped along and by the discharge out of the device, with the result that smaller diffusion pumps are required than would otherwise be necessary to dispose of the excess gas.

  18. Improving Hospital Discharge Time

    PubMed Central

    El-Eid, Ghada R.; Kaddoum, Roland; Tamim, Hani; Hitti, Eveline A.

    2015-01-01

    Abstract Delays in discharging patients can impact hospital and emergency department (ED) throughput. The discharge process is complex and involves setting specific challenges that limit generalizability of solutions. The aim of this study was to assess the effectiveness of using Six Sigma methods to improve the patient discharge process. This is a quantitative pre and post-intervention study. Three hundred and eighty-six bed tertiary care hospital. A series of Six Sigma driven interventions over a 10-month period. The primary outcome was discharge time (time from discharge order to patient leaving the room). Secondary outcome measures included percent of patients whose discharge order was written before noon, percent of patients leaving the room by noon, hospital length of stay (LOS), and LOS of admitted ED patients. Discharge time decreased by 22.7% from 2.2 hours during the preintervention period to 1.7 hours post-intervention (P < 0.001). A greater proportion of patients left their room before noon in the postintervention period (P < 0.001), though there was no statistical difference in before noon discharge. Hospital LOS dropped from 3.4 to 3.1 days postintervention (P < 0.001). ED mean LOS of patients admitted to the hospital was significantly lower in the postintervention period (6.9 ± 7.8 vs 5.9 ± 7.7 hours; P < 0.001). Six Sigma methodology can be an effective change management tool to improve discharge time. The focus of institutions aspiring to tackle delays in the discharge process should be on adopting the core principles of Six Sigma rather than specific interventions that may be institution-specific. PMID:25816029

  19. Different subtypes of impulsivity differentiate uncontrolled eating and dietary restraint.

    PubMed

    Leitch, Margaret A; Morgan, Michael J; Yeomans, Martin R

    2013-10-01

    The current study explored the relationship between three subtypes of impulsivity (Reflection Impulsivity, Impulsive Choice, and Impulsive Action) and measures of uncontrolled eating (TFEQ-D) and restraint (TFEQ-R). Eighty women classified as scoring higher or lower on TFEQ-D and TFEQ-R completed the Matching Familiar Figures Test (MFFT20), Delay Discounting Task (DDT), a Go No Go task, Balloon Analogue Risk Task (BART), and the Barrett Impulsivity Scale-11 (BIS-11). To test whether these relationships were affected by enforced controls overeating, half of the participants fasted the night before and ate breakfast in the laboratory before testing and half had no such control. Women scoring higher on the TFEQ-D were significantly more impulsive on the MFFT20 and BIS-11 overall but not on DDT, Go No Go or BART. Women scoring higher on TFEQ-R were significantly less impulsive on the Go No Go task but did not differ on other measures. The eating manipulation modulated responses on the BART and BIS-11 non-planning scale depending on TFEQ-D classification. These results confirm recent data that high scores on TFEQ-D are related to impulsivity, but imply this relates more to Reflection Impulsivity rather than Impulsive Choice or Action. In contrast restrained eating was associated with better inhibitory control. Taken together, these results suggest that subtypes of impulsivity further differentiate uncontrolled eating and restraint, and suggest that a poor ability to reflect on decisions may underlie some aspects of overeating.

  20. Narcissism predicts impulsive buying: phenotypic and genetic evidence.

    PubMed

    Cai, Huajian; Shi, Yuanyuan; Fang, Xiang; Luo, Yu L L

    2015-01-01

    Impulsive buying makes billions of dollars for retail businesses every year, particularly in an era of thriving e-commerce. Narcissism, characterized by impulsivity and materialism, may serve as a potential antecedent to impulsive buying. To test this hypothesis, two studies examined the relationship between narcissism and impulsive buying. In Study 1, we surveyed an online sample and found that while adaptive narcissism was not correlated with impulsive buying, maladaptive narcissism was significantly predictive of the impulsive buying tendency. By investigating 304 twin pairs, Study 2 showed that global narcissism and its two components, adaptive and maladaptive narcissism, as well as the impulsive buying tendency were heritable. The study found, moreover, that the connections between global narcissism and impulsive buying, and between maladaptive narcissism and impulsive buying were genetically based. These findings not only establish a link between narcissism and impulsive buying but also help to identify the origins of the link. The present studies deepen our understanding of narcissism, impulsive buying, and their interrelationship.

  1. Narcissism predicts impulsive buying: phenotypic and genetic evidence

    PubMed Central

    Cai, Huajian; Shi, Yuanyuan; Fang, Xiang; Luo, Yu L. L.

    2015-01-01

    Impulsive buying makes billions of dollars for retail businesses every year, particularly in an era of thriving e-commerce. Narcissism, characterized by impulsivity and materialism, may serve as a potential antecedent to impulsive buying. To test this hypothesis, two studies examined the relationship between narcissism and impulsive buying. In Study 1, we surveyed an online sample and found that while adaptive narcissism was not correlated with impulsive buying, maladaptive narcissism was significantly predictive of the impulsive buying tendency. By investigating 304 twin pairs, Study 2 showed that global narcissism and its two components, adaptive and maladaptive narcissism, as well as the impulsive buying tendency were heritable. The study found, moreover, that the connections between global narcissism and impulsive buying, and between maladaptive narcissism and impulsive buying were genetically based. These findings not only establish a link between narcissism and impulsive buying but also help to identify the origins of the link. The present studies deepen our understanding of narcissism, impulsive buying, and their interrelationship. PMID:26217251

  2. Subjective field study of response to impulsive helicopter noise

    NASA Technical Reports Server (NTRS)

    Powell, C. A.

    1981-01-01

    Subjects, located outdoors and indoors, judged the noisiness and other subjective noise characteristics of flyovers of two helicopters and a propeller driven airplane as part of a study of the effects of impulsiveness on the subjective response to helicopter noise. In the first experiment, the impulsive characteristics of one helicopter was controlled by varying the main rotor speed while maintaining a constant airspeed in level flight. The second experiment which utilized only the helicopters, included descent and level flight operations. The more impulsive helicopter was consistently judged less noisy than the less impulsive helicopter at equal effective perceived noise levels (EPNL). The ability of EPNL to predict noisiness was not improved by the addition of either of two proposed impulse corrections. A subjective measure of impulsiveness, however, which was not significantly related to the proposed impulse corrections, was found to improve the predictive ability of EPNL.

  3. Adaptive impulsive cluster synchronization in community network with nonidentical nodes

    NASA Astrophysics Data System (ADS)

    Gong, Xiaoli; Gan, Luyining; Wu, Zhaoyan

    2016-07-01

    In this paper, cluster synchronization in community network with nonidentical nodes is investigated. Through introducing proper adaptive strategy into impulsive control scheme, adaptive impulsive controllers are designed for achieving the cluster synchronization. In this adaptive impulsive control scheme, for any given networks, the impulsive gains can adjust themselves to proper values according to the proposed adaptive strategy when the impulsive intervals are fixed. The impulsive instants can be estimated by solving a sequence of maximum value problems when the impulsive gains are fixed. Both community networks without and with coupling delay are considered. Based on the Lyapunov function method and mathematical analysis technique, two synchronization criteria are derived. Several numerical examples are performed to verify the effectiveness of the derived theoretical results.

  4. Multidimensional Examination of Impulsivity in Relation to Disordered Gambling

    PubMed Central

    MacKillop, James; Miller, Joshua D.; Fortune, Erica; Maples, Jessica; Lance, Charles E.; Campbell, W. Keith; Goodie, Adam S.

    2014-01-01

    Impulsivity has been consistently associated with pathological gambling (PG), but the diversity of definitions and measures of impulsivity has led to ambiguity with regard to which indices are independently relevant. Toward clarifying this relationship, the current study examined indices from an array of commonly-used impulsivity measures in relation to PG severity in an adult community sample of frequent gamblers (N = 353). These included both survey assessments and behavioral tasks. Using a factor analytic approach, four latent factors were identified among 19 indices and were designated reward sensitivity, punishment sensitivity, delay discounting, and cognitive impulsivity. All four latent variables were positively and independently related to PG severity, albeit at a trend level for cognitive impulsivity in a combined model. These findings reveal four generally independent domains of impulsivity that are related to PG severity, clarify which assessment measures aggregate in each domain, and illustrate the importance of measurement specificity in studying impulsivity in relation to PG and other psychiatric disorders. PMID:24708148

  5. Volume Diffuse Dielectric Barrier Discharge Plasma Produced by Nanosecond High Voltage Pulse in Airflow

    NASA Astrophysics Data System (ADS)

    Qi, Haicheng; Gao, Wei; Fan, Zhihui; Liu, Yidi; Ren, Chunsheng

    2016-05-01

    Volume diffuse dielectric barrier discharge (DBD) plasma is produced in subsonic airflow by nanosecond high-voltage pulse power supply with a plate-to-plate discharge cell at 6 mm air gap length. The discharge images, optical emission spectra (OES), the applied voltage and current waveforms of the discharge at the changed airflow rates are obtained. When airflow rate is increased, the transition of the discharge mode and the variations of discharge intensity, breakdown characteristics and the temperature of the discharge plasma are investigated. The results show that the discharge becomes more diffuse, discharge intensity is decreased accompanied by the increased breakdown voltage and time lag, and the temperature of the discharge plasma reduces when airflow of small velocity is introduced into the discharge gap. These phenomena are because that the airflow changes the spatial distribution of the heat and the space charge in the discharge gap. supported by National Natural Science Foundation of China (No. 51437002)

  6. Pinning impulsive control algorithms for complex network

    SciTech Connect

    Sun, Wen; Lü, Jinhu; Chen, Shihua; Yu, Xinghuo

    2014-03-15

    In this paper, we further investigate the synchronization of complex dynamical network via pinning control in which a selection of nodes are controlled at discrete times. Different from most existing work, the pinning control algorithms utilize only the impulsive signals at discrete time instants, which may greatly improve the communication channel efficiency and reduce control cost. Two classes of algorithms are designed, one for strongly connected complex network and another for non-strongly connected complex network. It is suggested that in the strongly connected network with suitable coupling strength, a single controller at any one of the network's nodes can always pin the network to its homogeneous solution. In the non-strongly connected case, the location and minimum number of nodes needed to pin the network are determined by the Frobenius normal form of the coupling matrix. In addition, the coupling matrix is not necessarily symmetric or irreducible. Illustrative examples are then given to validate the proposed pinning impulsive control algorithms.

  7. Elegant impulser developed for flat beam injection

    SciTech Connect

    Wilson, M. J., LLNL

    1998-05-26

    The following report describes the design, construction, and checkout of a high-voltage (HV) impulser built for the heavy ion fusion (HIF) project [1]. The purpose of this impulser is to provide an adjustable diode voltage source of sufficient quality and level to allow the optimization of beam transport and accelerator sections of HIF [2, 3]. An elegant, low-impedance, high-energy storage capacitor circuit has been selected for this application. Circuit parameters of the retrofit to the diode region [4] have been included to provide the controlled rise time. The critical part of this circuit that is common to all candidates is the impedance matching component. The following report provides a description of the implemented circuit, the basic circuit variables for wave shaping, screening techniques revealing the weakest circuit component, and the resulting output of the injector.

  8. Pulsed electrical discharge in conductive solution

    NASA Astrophysics Data System (ADS)

    Panov, V. A.; Vasilyak, L. M.; Vetchinin, S. P.; Pecherkin, V. Ya; Son, E. E.

    2016-09-01

    Electrical discharge in a conductive solution of isopropyl alcohol in tap water (330 μ S cm-1) has been studied experimentally applying high voltage millisecond pulses (rise time  ˜0.4 μ \\text{s} , amplitude up to 15 kV, positive polarity) to a pin anode electrode. Dynamic current-voltage characteristics synchronized with high-speed images of the discharge were studied. The discharge was found to develop from high electric field region in the anode vicinity where initial conductive current with density  ˜100 A cm-2 results in fast heating and massive nucleation of vapor bubbles. Discharges in nucleated bubbles then produce a highly conductive plasma region and facilitate overheating instability development with subsequent formation of a thermally ionized plasma channel. The measured plasma channel propagation speed was 3-15 m s-1. A proposed thermal model of plasma channel development explains the low observed plasma channel propagation speed.

  9. The hydraulic ram (or impulse) pump

    NASA Astrophysics Data System (ADS)

    Mills, Allan

    2014-03-01

    The hydraulic impulse pump utilizes a fraction of the momentum of a flowing stream to lift a small portion of that water to a higher level. There it may be accumulated in an elevated cistern to provide sufficient water for several families, for the pump works 24 h a day with no additional source of energy. The operation of the pump is described, along with a working demonstration model constructed from plastic waste pipe and fittings.

  10. The Hydraulic Ram (Or Impulse) Pump

    ERIC Educational Resources Information Center

    Mills, Allan

    2014-01-01

    The hydraulic impulse pump utilizes a fraction of the momentum of a flowing stream to lift a small portion of that water to a higher level. There it may be accumulated in an elevated cistern to provide sufficient water for several families, for the pump works 24 h a day with no additional source of energy. The operation of the pump is described,…

  11. UWB Impulse Radar Characterization and Processing Techniques

    DTIC Science & Technology

    2004-12-01

    S/B s’améliore de façon à peu près linéaire . L’intégration d’environ 80 impulsions donne lieu à un rapport S/B maximal d’environ 35 dB, avec une...défense Canada (RDDC) a un programme de recherche active sur bien des aspects des systèmes radar à bande ultra-large (UWB), y compris la simulation

  12. Temporal Characteristics of Impulsive Electron Precipitation Associated with Thunderstorm Activity

    NASA Astrophysics Data System (ADS)

    McCarthy, M.; Smith, D. M.; Bowers, G. S.; Millan, R. M.; Holzworth, R. H.

    2013-12-01

    The precipitation of energetic electrons from the magnetosphere through interactions with VLF radiation, launched by lightning discharges, has been studied both directly, using electron instruments on spacecraft, and indirectly, through consequent modification of the Earth-ionosphere waveguide. This work addresses the question of the time profile of lightning-induced electron precipitation (LEP). While satellite motion combines spatial and temporal effects into precipitation observations, and RF methods convolve ionospheric response processes with precipitation time scales, balloon observations of bremsstrahlung x-rays from LEP provide a clean measurement of the precipitation time profile. We report on observations of impulsive energetic electron precipitation, identified as LEP, made from a balloon platform over Antarctica during the BARREL campaign of 2013, and compare with earlier observations. Because thunderstorm activity is a strong and ever-present source of VLF power into the magnetosphere, it is believed that LEP processes play an important role in adjusting radiation belt fluxes. An accurate description of LEP's time development is important because this information constrains theories and parameters of the causative processes for LEP.

  13. Three dimensional breakdown of an impulsively forced laminar separation bubble

    NASA Astrophysics Data System (ADS)

    Michelis, Theodoros; Kotsonis, Marios

    2016-11-01

    The spatio-temporal behaviour of a short laminar separation bubble is investigated experimentally. The bubble develops on a flat plate driven by an adverse pressure gradient wall at Reynolds number based on displacement thickness at separation of Reδs* = 975 . The boundary layer is impulsively forced by means of AC dielectric barrier discharge plasma actuator located upstream of the separation point. The full four-dimensional flow development is captured by time resolved tomographic PIV measurements using the multi-pass light amplification technique. Immediately after forcing, a convectively unstable wave packet emerges due to selective amplification of modes which interacts with the reattachment process. The interaction becomes non-linear at the reattachment region, where Λ structures typical of laminar separation bubbles are captured before the occurrence of breakdown. The structures and breakdown are characterised in terms of temporal evolution, spanwise coherence and energy budget. The diminishing of Λ structures triggers a sharp reduction in size of the separation bubble by interfering with the natural shedding process. As a result, the bubble significantly elongates without shedding undergoing bursting before recovering to its unperturbed state.

  14. Winning and Losing: Effects on Impulsive Action

    PubMed Central

    2016-01-01

    In the present study, we examined the effect of wins and losses on impulsive action in gambling (Experiments 1–3) and nongambling tasks (Experiments 4–5). In each experiment, subjects performed a simple task in which they had to win points. On each trial, they had to choose between a gamble and a nongamble. The gamble was always associated with a higher amount but a lower probability of winning than the nongamble. After subjects indicated their choice (i.e., gamble or not), feedback was presented. They had to press a key to start the next trial. Experiments 1–3 showed that, compared to the nongambling baseline, subjects were faster to initiate the next trial after a gambled loss, indicating that losses can induce impulsive actions. In Experiments 4 and 5, subjects alternated between the gambling task and a neutral decision-making task in which they could not win or lose points. Subjects were faster in the neutral decision-making task if they had just lost in the gambling task, suggesting that losses have a general effect on action. Our results challenge the dominant idea that humans become more cautious after suboptimal outcomes. Instead, they indicate that losses in the context of potential rewards are emotional events that increase impulsivity. PMID:27808548

  15. Impulsive Reconnection in the Sun's Atmosphere

    NASA Technical Reports Server (NTRS)

    Antiochos, Spiro K.

    2009-01-01

    Recent high-resolution observations from the Hinode mission show dramatically that the Sun's atmosphere is filled with explosive activity ranging from chromospheric explosions that reach heights of Mm, to coronal jets that can extend to solar radii, to giant coronal mass ejections (CME) that reach the edge of the heliosphere. The driver for all this activity is believed to be 3D magnetic reconnection. From the large variation observed in the temporal behavior of solar activity, it is clear that reconnection in the corona must take on a variety of distinct forms. The explosive nature of jets and CMEs requires that the reconnection be impulsive in that it stays off until a substantial store of free energy has been accumulated, but then turns on abruptly and stays on until much of this free energy is released. The key question, therefore, is what determines whether the reconnection is impulsive or not. We present some of the latest observations and numerical models of explosive and non-explosive solar activity. We argue that, in order for the reconnection to be impulsive, it must be driven by a quasi-ideal instability. We discuss the generality of our results for understanding 31) reconnection in other contexts.

  16. Surface-Enhanced Impulsive Coherent Vibrational Spectroscopy

    NASA Astrophysics Data System (ADS)

    Du, Juan; Harra, Juha; Virkki, Matti; Mäkelä, Jyrki M.; Leng, Yuxin; Kauranen, Martti; Kobayashi, Takayoshi

    2016-11-01

    Surface-enhanced Raman spectroscopy (SERS) has attracted a lot of attention in molecular sensing because of the remarkable ability of plasmonic metal nanostructures to enhance the weak Raman scattering process. On the other hand, coherent vibrational spectroscopy triggered by impulsive excitation using ultrafast laser pulses provides complete information about the temporal evolution of molecular vibrations, allowing dynamical processes in molecular systems to be followed in “real time”. Here, we combine these two concepts and demonstrate surface-enhanced impulsive vibrational spectroscopy. The vibrational modes of the ground and excited states of poly[2-methoxy-5-(2-ethylhexyloxy)‑1,4-phenylenevinylene] (MEH-PPV), spin-coated on a substrate covered with monodisperse silver nanoparticles, are impulsively excited with a sub-10 fs pump pulse and characterized with a delayed broad-band probe pulse. The maximum enhancement in the spectrally and temporally resolved vibrational signatures averaged over the whole sample is about 4.6, while the real-time information about the instantaneous vibrational amplitude together with the initial vibrational phase is preserved. The phase is essential to determine the vibrational contributions from the ground and excited states.

  17. Surface-Enhanced Impulsive Coherent Vibrational Spectroscopy

    PubMed Central

    Du, Juan; Harra, Juha; Virkki, Matti; Mäkelä, Jyrki M.; Leng, Yuxin; Kauranen, Martti; Kobayashi, Takayoshi

    2016-01-01

    Surface-enhanced Raman spectroscopy (SERS) has attracted a lot of attention in molecular sensing because of the remarkable ability of plasmonic metal nanostructures to enhance the weak Raman scattering process. On the other hand, coherent vibrational spectroscopy triggered by impulsive excitation using ultrafast laser pulses provides complete information about the temporal evolution of molecular vibrations, allowing dynamical processes in molecular systems to be followed in “real time”. Here, we combine these two concepts and demonstrate surface-enhanced impulsive vibrational spectroscopy. The vibrational modes of the ground and excited states of poly[2-methoxy-5-(2-ethylhexyloxy)−1,4-phenylenevinylene] (MEH-PPV), spin-coated on a substrate covered with monodisperse silver nanoparticles, are impulsively excited with a sub-10 fs pump pulse and characterized with a delayed broad-band probe pulse. The maximum enhancement in the spectrally and temporally resolved vibrational signatures averaged over the whole sample is about 4.6, while the real-time information about the instantaneous vibrational amplitude together with the initial vibrational phase is preserved. The phase is essential to determine the vibrational contributions from the ground and excited states. PMID:27812020

  18. Impulsive Injection for Compressor Stator Separation Control

    NASA Technical Reports Server (NTRS)

    Culley, Dennis E.; Braunscheidel, Edward P.; Bright, Michelle M.

    2005-01-01

    Flow control using impulsive injection from the suction surface of a stator vane has been applied in a low speed axial compressor. Impulsive injection is shown to significantly reduce separation relative to steady injection for vanes that were induced to separate by an increase in vane stagger angle of 4 degrees. Injected flow was applied to the airfoil suction surface using spanwise slots pitched in the streamwise direction. Injection was limited to the near-hub region, from 10 to 36 percent of span, to affect the dominant loss due to hub leakage flow. Actuation was provided externally using high-speed solenoid valves closely coupled to the vane tip. Variations in injected mass, frequency, and duty cycle are explored. The local corrected total pressure loss across the vane at the lower span region was reduced by over 20 percent. Additionally, low momentum fluid migrating from the hub region toward the tip was effectively suppressed resulting in an overall benefit which reduced corrected area averaged loss through the passage by 4 percent. The injection mass fraction used for impulsive actuation was typically less than 0.1 percent of the compressor through flow.

  19. The thermal impulse response of Escherichia coli

    PubMed Central

    Paster, Eli; Ryu, William S.

    2008-01-01

    Swimming Escherichia coli responds to changes in temperature by modifying its motor behavior. Previous studies using populations of cells have shown that E. coli accumulate in spatial thermal gradients, but these experiments did not cleanly separate thermal responses from chemotactic responses. Here we have isolated the thermal response by studying the behavior of single, tethered cells. The motor output of cells grown at 33°C was measured at constant temperature, from 10° to 40°C, and in response to small, impulsive increases in temperature, from 23° to 43°C. The thermal impulse response at temperatures < 31°C is similar to the chemotactic impulse response: Both follow a similar time course, share the same directionality, and show biphasic characteristics. At temperatures > 31°C, some cells show an inverted response, switching from warm- to cold-seeking behavior. The fraction of inverted responses increases nonlinearly with temperature, switching steeply at the preferred temperature of 37°C. PMID:18385380

  20. Impulse noise generated by starter pistols

    PubMed Central

    Meinke, Deanna K.; Finan, Donald S.; Soendergaard, Jacob; Flamme, Gregory A.; Murphy, William J.; Lankford, James E.; Stewart, Michael

    2015-01-01

    Objective This study describes signals generated by .22 and .32 caliber starter pistols in the context of noise-induced hearing loss risk for sports officials and athletes. Design Acoustic comparison of impulses generated from typical .22 and .32 caliber starter pistols firing blanks were made to impulses generated from comparable firearms firing both blanks and live rounds. Acoustic characteristics are described in terms of directionality and distance from the shooter in a simulated outdoor running track. Metrics include peak sound pressure levels (SPL), A-weighted equivalent 8-hour level (LeqA8), and maximum permissible number of individual shots, or maximum permissible exposures (MPE) for the unprotected ear. Results Starter pistols produce peak SPLs above 140 dB. The numbers of MPEs are as few as five for the .22-caliber starter pistol, and somewhat higher (≤25) for the .32-caliber pistol. Conclusion The impulsive sounds produced by starter pistols correspond to MPE numbers that are unacceptably small for unprotected officials and others in the immediate vicinity of the shooter. At the distances included in this study, the risk to athletes appears to be low (when referencing exposure criteria for adults), but the sound associated with the starter pistol will contribute to the athlete’s overall noise exposure. PMID:23373743

  1. Dysregulated Glycine Signaling Contributes to Increased Impulsivity during Protracted Alcohol Abstinence.

    PubMed

    Irimia, Cristina; Buczynski, Matthew W; Natividad, Luis A; Laredo, Sarah A; Avalos, Nathaniel; Parsons, Loren H

    2017-02-15

    Persons with alcoholism who are abstinent exhibit persistent impairments in the capacity for response inhibition, and this form of impulsivity is significantly associated with heightened relapse risk. Brain-imaging studies implicate aberrant prefrontal cortical function in this behavioral pathology, although the underlying mechanisms are not understood. Here we present evidence that deficient activation of glycine and serine release in the ventral medial prefrontal cortex (vmPFC) contributes to increased motor impulsivity during protracted abstinence from long-term alcohol exposure. Levels of 12 neurotransmitters were monitored in the rat vmPFC during the performance of a challenging variant of the five-choice serial reaction time task (5-CSRTT) in which alcohol-exposed rats exhibit excessive premature responding. Following long-term ethanol exposure, rats showed blunted task-related recruitment of vmPFC glycine and serine release, and the loss of an inverse relationship between levels of these neurotransmitters and premature responding normally evident in alcohol-naive subjects. Intra-vmPFC administration of the glycine transport inhibitor ALX5407 prevented excessive premature responding by alcohol-exposed rats, and this was reliant on NMDA glycine site availability. Alcohol-exposed rats and controls did not differ in their premature responding and glycine and serine levels in vmPFC during the performance of the standard 5-CSRTT. Collectively, these findings provide novel insight into cortical neurochemical mechanisms contributing to increased impulsivity following long-term alcohol exposure and highlight the NMDA receptor coagonist site as a potential therapeutic target for increased impulsivity that may contribute to relapse risk.SIGNIFICANCE STATEMENT Persons with alcoholism demonstrate increased motor impulsivity during abstinence; however, the neuronal mechanisms underlying these behavioral effects remain unknown. Here, we took advantage of an animal model

  2. Impulse control and restrained eating among young women: Evidence for compensatory cortical activation during a chocolate-specific delayed discounting task.

    PubMed

    Dong, Debo; Wang, Yulin; Jackson, Todd; Chen, Shuaiyu; Wang, Yu; Zhou, Feng; Chen, Hong

    2016-10-01

    Theory and associated research indicate that people with elevated restrained eating (RE) scores have higher risk for binge eating, future bulimic symptom onset and weight gain. Previous imaging studies have suggested hyper-responsive reward brain area activation in response to food cues contributes to this risk but little is known about associated neural impulse control mechanisms, especially when considering links between depleted cognitive resources related to unsuccessful RE. Towards illuminating this issue, we used a chocolate-specific delayed discounting (DD) task to investigate relations between RE scores, behavior impulsivity, and corresponding neural impulse control correlates in a functional magnetic resonance imaging (fMRI) study of 27 young women. Specifically, participants were required to choose between more immediate, smaller versus delayed, larger hypothetical chocolate rewards following initial consumption of a chocolate. As predicted, RE scores were correlated positively with behavior impulse control levels. More critically, higher RE scores were associated with stronger activation in impulse control region, the dorsal-lateral prefrontal cortex (DLPFC) during the completion of difficult decision trials reflecting higher cognitive demands and resource depletion relative to easy decision trials. Exploratory analyses revealed a positive correlation between RE scores and activity in a reward system hub, the right striatum. Moreover, a positive correlation between left DLPFC and striatum activation was posited to reflect, in part, impulse control region compensation in response to stronger reward signal among women with RE elevations. Findings suggested impulse control lapses may contribute to difficulties in maintaining RE, particularly when cognitive demands are high.

  3. Glow discharge detector

    DOEpatents

    Koo, Jackson C.; Yu, Conrad M.

    2002-01-01

    A highly sensitive electronic ion cell for the measurement of trace elements in He carrier gas which involves glow discharge. A constant wave (CW) glow discharge detector which is controlled through a biased resistor, can detect the change of electron density caused by impurities in the He carrier gas by many orders of magnitude larger than that caused by direct ionization or electron capture. The glow discharge detector utilizes a floating pseudo-electrode to form a probe in or near the plasma. By using this probe, the large variation of electron density due to trace amounts of impurities can be directly measured.

  4. INTENSE ENERGETIC GAS DISCHARGE

    DOEpatents

    Luce, J.S.

    1960-03-01

    A method and apparatus for initiating and sustaining an energetic gas arc discharge are described. A hollow cathode and a hollow anode are provided. By regulating the rate of gas flow into the interior of the cathode, the arc discharge is caused to run from the inner surface of the cathode with the result that adequate space-charge neutralization is provided inside the cathode but not in the main arc volume. Thus, the gas fed to the cathode is substantially completely ionized before it leaves the cathode, with the result that an energetic arc discharge can be maintained at lower operating pressures.

  5. Discharge lamp technologies

    NASA Technical Reports Server (NTRS)

    Dakin, James

    1994-01-01

    This talk is an overview of discharge lamp technology commonly employed in general lighting, with emphasis on issues pertinent to lighting for plant growth. Since the audience is primarily from the plant growth community, and this begins the light source part of the program, we will start with a brief description of the discharge lamps. Challenges of economics and of thermal management make lamp efficiency a prime concern in controlled environment agriculture, so we will emphasize science considerations relating to discharge lamp efficiency. We will then look at the spectra and ratings of some representative lighting products, and conclude with a discussion of technological advances.

  6. Analyses and tests for design of an electro-impulse de-icing system

    NASA Technical Reports Server (NTRS)

    Zumwalt, G. W.; Schrag, R. L.; Bernhart, W. D.; Friedberg, R. A.

    1985-01-01

    De-icing of aircraft by using the electro-magnetic impulse phenomenon was proposed and demonstrated in several European countries. However, it is not available as a developed system due to lack of research on the basic physical mechanisms and necessary design parameters. The de-icing is accomplished by rapidly discharging high voltage capacitors into a wire coil rigidly supported just inside the aircraft skin. Induced eddy currents in the skin create a repulsive force resulting in a hammer-like force which cracks, de-bonds, and expels ice on the skin surface. The promised advantages are very low energy, high reliability of de-icing, and low maintenance. Three years of Electo-Impulse De-icing (EIDI) research is summarized and the analytical studies and results of testing done in the laboratory, in the NASA Icing Research Tunnel, and in flight are presented. If properly designed, EIDI was demonstrated to be an effective and practical ice protection system for small aircraft, turbojet engine inlets, elements of transport aircraft, and shows promise for use on helicopter rotor blades. Included are practical techniques of fabrication of impulse coils and their mountings. The use of EIDI with nonmetallic surface materials is also described.

  7. Dimensions of impulsive behavior in adolescent smokers and nonsmokers.

    PubMed

    Fields, Sherecce; Collins, Christine; Leraas, Kristen; Reynolds, Brady

    2009-10-01

    Robust associations have been identified between impulsive personality characteristics and cigarette smoking during adolescents, indicating that impulsive behavior may play an important role in the initiation of cigarette smoking. The present study extended this research by using laboratory behavioral assessments to explore relationships between three specific dimensions of impulsive behavior (impulsive decision-making, inattention, and disinhibition) and adolescent cigarette smoking. Participants were male and female adolescent smokers (n = 50) and nonsmokers (n = 50). Adolescent smokers were more impulsive on a measure of decision-making; however, there were significant smoking status by gender interaction effects for impulsive inattention and disinhibition. Male smokers were most impulsive on the measure of inattention, but male smokers were least impulsive on the measure of disinhibition. Correlations between biomarkers of smoking and impulsive inattention and disinhibition were found for females but not males. The current findings, coupled with previous findings (Reynolds et al., 2007), indicate there may be robust gender difference in associations between certain types of impulsive behavior and cigarette smoking during adolescence.

  8. Evaluating Eve: visceral states influence the evaluation of impulsive behavior.

    PubMed

    Nordgren, Loran F; van der Pligt, Joop; van Harreveld, Frenk

    2007-07-01

    Impulsive behavior is a common source of stigma. The authors argue that people often stigmatize impulsive behavior because they fail to appreciate the influence visceral impulses have on behavior. Because people tend to underestimate the motivational force of cravings for sex, drugs, food, and so forth, they are prone to stigmatize those who act on these impulses. In line with this reasoning, in 4 studies, the authors found that participants who were in a cold state (e.g., not hungry) made less favorable evaluations of a related impulsive behavior (impulsive eating) than did participants who were in a hot state (e.g., hungry). This empathy gap effect was tested with 3 different visceral states--fatigue, hunger, and sexual arousal--and was found both when participants evaluated others' impulsive behavior (Studies 1 & 2) and when participants evaluated their own impulsive behavior (Study 3). Study 3 also demonstrated that the empathy gap effect is due to different perceptions of the strength of the visceral state itself. Finally, Study 4 revealed that this effect is state specific: Hungry people, for example, evaluated only hunger-driven impulses, and not other forms of impulse, more favorably.

  9. Quality of life and impulsivity in bipolar disorder

    PubMed Central

    Victor, Sarah E; Johnson, Sheri L; Gotlib, Ian H

    2011-01-01

    Objectives Bipolar disorder (BD) is a chronic psychiatric illness that impairs quality of life (QoL) in numerous life domains even when mood symptoms are not present and is characterized by elevated impulsivity. Many of the comorbid conditions that are associated with diminished QoL in BD also involve impulsivity. The objective of this project was to investigate whether impulsivity might mediate the effects of these comorbid conditions on poor QoL. Methods A total of 76 participants diagnosed with bipolar I disorder by the Structured Clinical Interview for DSM-IV Axis I disorders completed the Quality of Life in Bipolar Disorder (QoL-BD) scale, the Barratt Impulsivity Scale (BIS-11), and the Positive Urgency Measure (PUM). Participants were also assessed for comorbid DSM-IV diagnoses of anxiety, substance use, and impulse control disorders. Results Several subscales of the BIS-11 as well as the PUM total score were significantly negatively correlated with overall QoL. PUM total score remained a significant predictor of QoL after controlling for comorbid anxiety, substance use, and impulse control disorders. After controlling for impulsivity, comorbid disorders were no longer significantly related to overall QoL. Conclusions The data support the hypothesis that impulsivity, specifically positive urgency, is highly correlated with QoL in BD. Impulsivity was found to mediate the relation between QoL and several comorbidities in BD. Interventions targeting impulsivity might help to improve QoL in BD. PMID:21676133

  10. Impulsivity and Cigarette Craving among Adolescent Daily and Occasional Smokers

    PubMed Central

    Mathew, Amanda R.; Burris, Jessica L.; Froeliger, Brett; Saladin, Michael E.; Carpenter, Matthew J.

    2015-01-01

    Introduction Impulsivity is a multi-dimensional construct that is robustly related to cigarette smoking. While underlying factors that account for this relation are not well understood, craving has been proposed as a central mechanism linking impulsivity to smoking. In order to further refine our understanding of associations between impulsivity and cigarette craving, the current study examined the association between impulsivity and tonic and cue-elicited craving among a sample of adolescent smokers. We expected trait impulsivity would be positively associated with both tonic and cue-elicited craving, and that this relationship would be stronger among daily vs. occasional smokers. Methods 106 smokers (ages 16–20) completed questionnaires and reported their cigarette craving prior to and immediately following presentation of each of three counterbalanced cue types: (a) in vivo smoking, (b) alcohol, and (c) neutral cue. Results Impulsivity was positively associated with tonic craving for daily smokers (β=.38; p=.005), but not occasional smokers (β=.01; p=.95), with a significant impulsivity x smoker group interaction (β=1.31; p=.03). Impulsivity was unrelated to craving following smoking or alcohol cue, regardless of smoker group (all p’s>.16). Conclusions Results suggest a moderated effect in which impulsivity is positively associated with tonic craving for daily smokers, but not occasional smokers. Tonic craving may serve as a mechanism linking impulsivity, smoking persistence, and nicotine dependence among daily smokers. PMID:25665916

  11. The importance of corona generation and leader formation during laser filament guided discharges in air

    NASA Astrophysics Data System (ADS)

    Schmitt-Sody, Andreas; French, David; White, William; Lucero, Adrian; Roach, William P.; Hasson, Victor

    2015-03-01

    Images taken with an intensified CCD camera show the dynamics during filament guided discharge events. The images reveal that filament initiated corona plays a role in the presented results. Furthermore, the images show the formation of leaders, propagating and eventually bridging the gap between the high voltage (HV) electrodes. Analysis of the images and comparison to oscilloscope traces of voltage and current dynamics reveal the origin of the delay between the filament and HV discharge and allows for a probability of discharge analysis.

  12. Toward Understanding the Early Stags of an Impulsively Accelerated Coronal Mass Ejection

    DTIC Science & Technology

    2010-08-09

    formation and main acceleration in the inner corona , and up to several solar radii by the STEREO mission. These allow us to quantify the initial expansion of...Laboratory, Space Science Division, Washington, DC 20375, USA e-mail: vourlidas @nrl.navy.mil 3 University College London, Mullard Space Science...simultaneously fit to Solar Terrestrial Relations Observatory (STEREO) Extreme Ultraviolet Imager (EUVI) and Inner Coronagraph (COR1) data of an impulsively

  13. Observation and numerical modeling of chromospheric evaporation during the impulsive phase of a solar flare

    SciTech Connect

    Imada, Shinsuke; Murakami, Izumi; Watanabe, Tetsuya

    2015-10-15

    We have studied the chromospheric evaporation flow during the impulsive phase of the flare by using the Hinode/EUV Imaging Spectrometer observation and 1D hydrodynamic numerical simulation coupled to the time-dependent ionization. The observation clearly shows that the strong redshift can be observed at the base of the flaring loop only during the impulsive phase. We performed two different numerical simulations to reproduce the strong downflows in FeXII and FeXV during the impulsive phase. By changing the thermal conduction coefficient, we carried out the numerical calculation of chromospheric evaporation in the thermal conduction dominant regime (conductivity coefficient κ{sub 0} = classical value) and the enthalpy flux dominant regime (κ{sub 0} = 0.1 × classical value). The chromospheric evaporation calculation in the enthalpy flux dominant regime could reproduce the strong redshift at the base of the flare during the impulsive phase. This result might indicate that the thermal conduction can be strongly suppressed in some cases of flare. We also find that time-dependent ionization effect is important to reproduce the strong downflows in Fe XII and Fe XV.

  14. Development and automation of a test of impulse control in zebrafish

    PubMed Central

    Parker, Matthew O.; Ife, Dennis; Ma, Jun; Pancholi, Mahesh; Smeraldi, Fabrizio; Straw, Chris; Brennan, Caroline H.

    2013-01-01

    Deficits in impulse control (difficulties in inhibition of a pre-potent response) are fundamental to a number of psychiatric disorders, but the molecular and cellular basis is poorly understood. Zebrafish offer a very useful model for exploring these mechanisms, but there is currently a lack of validated procedures for measuring impulsivity in fish. In mammals, impulsivity can be measured by examining rates of anticipatory responding in the 5-choice serial reaction time task (5-CSRTT), a continuous performance task where the subject is reinforced upon accurate detection of a briefly presented light in one of five distinct spatial locations. This paper describes the development of a fully-integrated automated system for testing impulsivity in adult zebrafish. We outline the development of our image analysis software and its integration with National Instruments drivers and actuators to produce the system. We also describe an initial validation of the system through a one-generation screen of chemically mutagenized zebrafish, where the testing parameters were optimized. PMID:24133417

  15. Breast radiation - discharge

    MedlinePlus

    Radiation - breast - discharge ... away around 4 to 6 weeks after the radiation treatment is over. You may notice changes in ... breast looks or feels (if you are getting radiation after a lumpectomy). These changes include: Soreness or ...

  16. Brain radiation - discharge

    MedlinePlus

    Radiation - brain - discharge; Cancer-brain radiation; Lymphoma - brain radiation; Leukemia - brain radiation ... Decadron) while you are getting radiation to the brain. It may make you hungrier, cause leg swelling ...

  17. Heart failure - discharge

    MedlinePlus

    ... Heart failure - overview Heart pacemaker High blood pressure Implantable cardioverter-defibrillator Smoking - tips on how to quit ... ask your doctor How to read food labels Implantable cardioverter defibrillator - discharge Low-salt diet Mediterranean diet ...

  18. Concussion - child - discharge

    MedlinePlus

    ... this page: //medlineplus.gov/ency/patientinstructions/000125.htm Concussion in children - discharge To use the sharing features ... enable JavaScript. Your child was treated for a concussion . This is a mild brain injury that can ...

  19. Capacitor discharge pulse analysis.

    SciTech Connect

    Baker, Michael Sean; Griffiths, Stewart K.; Tanner, Danelle Mary

    2013-08-01

    Capacitors used in firing sets and other high discharge current applications are discharge tested to verify performance of the capacitor against the application requirements. Parameters such as capacitance, inductance, rise time, pulse width, peak current and current reversal must be verified to ensure that the capacitor will meet the application needs. This report summarizes an analysis performed on the discharge current data to extract these parameters by fitting a second-order system model to the discharge data and using this fit to determine the resulting performance metrics. Details of the theory and implementation are presented. Using the best-fit second-order system model to extract these metrics results in less sensitivity to noise in the measured data and allows for direct extraction of the total series resistance, inductance, and capacitance.

  20. Multiple sclerosis - discharge

    MedlinePlus

    ... this page: //medlineplus.gov/ency/patientinstructions/000129.htm Multiple sclerosis - discharge To use the sharing features on this ... Your doctor has told you that you have multiple sclerosis (MS). This disease affects the brain and spinal ...

  1. Uterine artery embolization - discharge

    MedlinePlus

    ... page: //medlineplus.gov/ency/patientinstructions/000161.htm Uterine artery embolization - discharge To use the sharing features on this page, please enable JavaScript. You had uterine artery embolization (UAE). UAE is a procedure to treat ...

  2. Deep vein thrombosis - discharge

    MedlinePlus

    ... this page: //medlineplus.gov/ency/patientinstructions/000027.htm Deep vein thrombosis - discharge To use the sharing features ... page, please enable JavaScript. You were treated for deep vein thrombosis ( DVT ). This is a condition in ...

  3. Knee arthroscopy - discharge

    MedlinePlus

    ... remove it. Torn or damaged anterior cruciate ligament (ACL) or posterior cruciate ligament (PCL) Inflamed or damaged ... surgery Knee pain Meniscal allograft transplantation Patient Instructions ACL reconstruction - discharge Getting your home ready - knee or ...

  4. Corneal transplant - discharge

    MedlinePlus

    ... page: //medlineplus.gov/ency/patientinstructions/000243.htm Corneal transplant - discharge To use the sharing features on this page, please enable JavaScript. You had a corneal transplant. Most of the tissue of your cornea (the ...

  5. Shoulder replacement - discharge

    MedlinePlus

    ... page: //medlineplus.gov/ency/patientinstructions/000178.htm Shoulder replacement - discharge To use the sharing features on this page, please enable JavaScript. You had shoulder replacement surgery to replace the bones of your shoulder ...

  6. Electric discharge during electrosurgery

    PubMed Central

    Shashurin, Alexey; Scott, David; Zhuang, Taisen; Canady, Jerome; Beilis, Isak I.; Keidar, Michael

    2015-01-01

    Electric discharge utilized for electrosurgery is studied by means of a recently developed method for the diagnostics of small-size atmospheric plasma objects based on Rayleigh scattering of microwaves on the plasma volume. Evolution of the plasma parameters in the near-electrode sheaths and in the positive column is measured and analyzed. It is found that the electrosurgical system produces a glow discharge of alternating current with strongly contracted positive column with current densities reaching 103 A/cm2. The plasma electron density and electrical conductivities in the channel were found be 1016 cm−3 and (1-2) Ohm−1cm−1, respectively. The discharge interrupts every instance when the discharge-driving AC voltage crosses zero and re-ignites again every next half-wave at the moment when the instant voltage exceeds the breakdown threshold. PMID:25880721

  7. Oil Discharge Reporting Requirements

    EPA Pesticide Factsheets

    If a facility or vessel discharges oil to navigable waters or adjoining shorelines, the owner/operator is required to follow certain federal reporting requirements. This fact sheet outlines those reporting requirements.

  8. Femur fracture repair - discharge

    MedlinePlus

    ... page: //medlineplus.gov/ency/patientinstructions/000166.htm Femur fracture repair - discharge To use the sharing features on this page, please enable JavaScript. You had a fracture (break) in the femur in your leg. It ...

  9. Crohn disease - discharge

    MedlinePlus

    ... diet Nasogastric feeding tube Small bowel resection - discharge Review Date 12/2/2014 Updated by: Jenifer K. ... Frankford-Torresdale Hospital, Aria Health System, Philadelphia, PA. Review provided by VeriMed Healthcare Network. Also reviewed by ...

  10. Cosmetic breast surgery - discharge

    MedlinePlus

    ... this page: //medlineplus.gov/ency/patientinstructions/000273.htm Cosmetic breast surgery - discharge To use the sharing features on this page, please enable JavaScript. You had cosmetic breast surgery to change the size or shape ...

  11. Shoulder surgery - discharge

    MedlinePlus

    ... this page: //medlineplus.gov/ency/patientinstructions/000179.htm Shoulder surgery - discharge To use the sharing features on this page, please enable JavaScript. You had shoulder surgery to repair the tissues inside or around ...

  12. Pneumonia - children - discharge

    MedlinePlus

    ... this page: //medlineplus.gov/ency/patientinstructions/000011.htm Pneumonia in children - discharge To use the sharing features ... this page, please enable JavaScript. Your child has pneumonia, which is an infection in the lungs. In ...

  13. The utility of rat models of impulsivity in developing pharmacotherapies for impulse control disorders

    PubMed Central

    Winstanley, Catharine A

    2011-01-01

    High levels of impulsive behaviours are a clinically significant symptom in a range of psychiatric disorders, such as attention deficit hyperactivity disorder, bipolar disorder, personality disorders, pathological gambling and substance abuse. Although often measured using questionnaire assessments, levels of different types of impulsivity can also be determined using behavioural tests. Rodent analogues of these paradigms have been developed, and similar neural circuitry has been implicated in their performance in both humans and rats. In the current review, the methodology underlying the measurement of different aspects of impulsive action and choice are considered from the viewpoint of drug development, with a focus on the continuous performance task (CPT), stop-signal task (SST), go/no-go and delay-discounting paradigms. Current issues impeding translation between animal and human studies are identified, and comparisons drawn between the acute effects of dopaminergic, noradrenergic and serotonergic compounds across species. Although the field could benefit from a more systematic determination of different pharmacological agents across paradigms, there are signs of strong concordance between the animal and human data. However, the type of impulsivity measured appears to play a significant role, with the SST and delay discounting providing more consistent effects for dopaminergic drugs, while the CPT and SST show better predictive validity so far for serotonergic and noradrenergic compounds. Based on the available data, it would appear that these impulsivity models could be used more widely to identify potential pharmacotherapies for impulse control disorders. Novel targets within the glutamatergic and serotonergic system are also suggested. LINKED ARTICLES This article is part of a themed issue on Translational Neuropharmacology. To view the other articles in this issue visit http://dx.doi.org/10.1111/bph.2011.164.issue-4 PMID:21410459

  14. Identifying discharge practice training needs.

    PubMed

    Lees, L; Emmerson, K

    A training needs analysis tool was developed to identify nurses' discharge training needs and to improve discharge practice. The tool includes 49 elements of discharge practice subdivided into four areas: corporate, operational, clinical and nurse-led discharge. The tool was disseminated to 15 wards on two hospital sites with assistance from the practice development team. Analysis of discharge training is important to assess discharge training needs and to identify staff who may assist with training.

  15. Coronal Mass Ejections Associated With Impulsive Solar Flares - Observations With SECCHI EUVI On STEREO

    NASA Astrophysics Data System (ADS)

    Nitta, N. V.; Lemen, J. R.; Wuelser, J.; Aschwanden, M. J.; Freeland, S. L.; Zarro, D. M.

    2008-12-01

    Long-duration flares, sometimes referred to as Long Decay Events (LDEs), are known to be unmistakable signatures of coronal mass ejections (CMEs), and often of fast and large ones. Short-duration or impulsive flares, on the other hand, do not as frequently accompany CMEs, even though X-ray plasmoid ejections seen in some of these flares may suggest that all flares are eruptive irrespective of durations. Some of these ejections in X-ray or EUV images could be failed ejections, however, meaning that they do not move into interplanetary medium. A complementary, and perhaps more reliable signature of a CME in the low corona may be large-scale dimming typically observed at 1-2 MK. We report on high cadence observations of SECCHI EUVI on STEREO that show this phenomenon in weak impulsive flares more frequently than expected. We systematically study flare periods with good data coverage. In order to avoid false dimming, we use both base and running difference images after carefully co-aligning the image pairs. Some of the dimming events were observed in more than one channel and at two widely separated view angles, letting us better understand the nature of dimming especially in terms of the associated CME. We discuss how the properties of dimming are reflected in CME parameters, how to distinguish the impulsive flares with large- scale effects from those that are confined, and whether similar events could account for orphan ICMEs without a clearly associated CME near the Sun.

  16. A Finite-Element Method Model of Soft Tissue Response to Impulsive Acoustic Radiation Force

    PubMed Central

    Palmeri, Mark L.; Sharma, Amy C.; Bouchard, Richard R.; Nightingale, Roger W.; Nightingale, Kathryn R

    2010-01-01

    Several groups are studying acoustic radiation force and its ability to image the mechanical properties of tissue. Acoustic radiation force impulse (ARFI) imaging is one modality using standard diagnostic ultrasound scanners to generate localized, impulsive, acoustic radiation forces in tissue. The dynamic response of tissue is measured via conventional ultrasonic speckle-tracking methods and provides information about the mechanical properties of tissue. A finite-element method (FEM) model has been developed that simulates the dynamic response of tissues, with and without spherical inclusions, to an impulsive acoustic radiation force excitation from a linear array transducer. These FEM models were validated with calibrated phantoms. Shear wave speed, and therefore elasticity, dictates tissue relaxation following ARFI excitation, but Poisson’s ratio and density do not significantly alter tissue relaxation rates. Increased acoustic attenuation in tissue increases the relative amount of tissue displacement in the near field compared with the focal depth, but relaxation rates are not altered. Applications of this model include improving image quality, and distilling material and structural information from tissue’s dynamic response to ARFI excitation. Future work on these models includes incorporation of viscous material properties and modeling the ultrasonic tracking of displaced scatterers. PMID:16382621

  17. Electromagnetic emissions from a modular Low Voltage Electro-Impulse De-icing system

    NASA Astrophysics Data System (ADS)

    Zieve, Peter; Huffer, Brent; Ng, James

    1989-03-01

    An important consideration in the certification of electro-impulse deicing (EIDI) systems for aircraft ice protection is electromagnetic interference (EMI). When the capacitor bank in an EIDI system discharges, a large pulse of current travels down a transmission line to the coil. Subsequent radiation by the transmission line and the coil produces EMI. The low voltage electro-impulse deicing system (LVEIDI) is unique in that the capacitor bank is mounted adjacent to the coil thereby eliminating most of the cables. Electromagnetic emissions from this system would then be primarily from the coil. The performed tests investigate the EMI environment inside and outside of both a composite and an aluminum wing. Due to the absence of the shielding effect of aluminum, the problem of electromagnetic emissions is particularly severe when the wing is constructed of composite materials. Measurements of the radiated electric field indicate that emissions from the aluminum wing were well within the standards. Some tests with the composite wing were within standards while others were not. It was found that the composite wing could be brought back into compliance through the addition of thin metallic shielding. Conducted emissions on the LVEIDI power feed cable were brought within standards with the addition of a line filter. An unshielded connection cable for a compass flux valve was run through the wing just behind the LVEIDI module. Discharge of the capacitor bank had no discernible effect on operation of the compass flux valve. No problems were observed in other tests of the wing internal environment.

  18. Self-reported impulsivity, but not behavioral choice or response impulsivity, partially mediates the effect of stress on drinking behavior.

    PubMed

    Hamilton, Kristen R; Ansell, Emily B; Reynolds, Brady; Potenza, Marc N; Sinha, Rajita

    2013-01-01

    Stress and impulsivity contribute to alcohol use, and stress may also act via impulsivity to increase drinking behavior. Impulsivity represents a multi-faceted construct and self-report and behavioral assessments may effectively capture distinct clinically relevant factors. The present research investigated whether aspects of impulsivity mediate the effect of stress on alcohol use. A community-based sample of 192 men and women was assessed on measures of cumulative stress, alcohol use, self-reported impulsivity, and behavioral choice and response impulsivity. Data were analyzed using regression and bootstrapping techniques to estimate indirect effects of stress on drinking via impulsivity. Cumulative adversity exhibited both direct effects and indirect effects (via self-reported impulsivity) on drinking behavior. Additional models examining specific types of stress indicated direct and indirect effects of trauma and recent life events, and indirect effects of major life events and chronic stressors on drinking behavior. Overall, cumulative stress was associated with increased drinking behavior, and this effect was partially mediated by self-reported impulsivity. Self-reported impulsivity also mediated the effects of different types of stress on drinking behavior. These findings highlight the value of mediation models to examine the pathways through which different types of stress increase drinking behavior. Treatment and prevention strategies should focus on enhancing stress management and self-control.

  19. Differences between Impulsive and Non-Impulsive Suicide Attempts among Individuals Treated in Emergency Rooms of South Korea

    PubMed Central

    Lim, Meerae; Lee, Soojung

    2016-01-01

    Objective A considerable proportion of suicide attempts are the result of sudden desires. Understanding such impulsive suicide attempts is necessary for effective interventions. We evaluated the impulsivity of suicide attempters treated in emergency rooms. The aim of the study was to identify the characteristics of impulsive suicide attempts by comparing these individuals to those who attempted to commit suicide in a non-impulsive manner. Methods This study analyzed suicide attempters who visited the emergency departments of seven selected university hospitals. A total of 269 medical records in which impulsivity of suicide attempt were confirmed were subject to be analyzed. The impulsivity of the suicide attempt was examined using a summative score of items 6 and 15 on the Suicide Intent Scale. Results A total of 48.0% of the participants were impelled by sudden inclinations to attempt suicide. Impulsive attempters were younger, unmarried and less physical illness than non-impulsive attempters, whereas no significant differences were found on psychiatric history and previous suicide history. Impulsive suicide attempters had suicide ideations that were not as severe (χ2=55.33, p<0.001) or intense (t=-8.38, p<0.001) as their counterparts'. Furthermore, medical results of impulsive suicide attempts were better than non-impulsive suicide attempts (t=-3.77, p<0.001). Conclusion The results suggested that a considerable proportion of suicide attempts were the result of sudden inclinations. Impulsive attempts were made in relatively earlier stages of suicide ideation; consequently, they have less intent than non-impulsive attempts. PMID:27482239

  20. Reconsidering the link between impulsivity and suicidal behavior.

    PubMed

    Anestis, Michael D; Soberay, Kelly A; Gutierrez, Peter M; Hernández, Theresa D; Joiner, Thomas E

    2014-11-01

    It is widely accepted that suicidal behavior often occurs with little planning. We propose, however, that suicidal behavior is rarely if ever impulsive-that it is too frightening and physically distressing to engage in without forethought-and that suicidal behavior in impulsive individuals is accounted for by painful and fearsome behaviors capable of enhancing their capacity for suicide. We conducted a meta-analysis of the association between trait impulsivity and suicidal behavior and a critical review of research considering the impulsiveness of specific suicide attempts. Meta-analytic results suggest the relationship between trait impulsivity and suicidal behavior is small. Furthermore, studies examining a mediating role of painful and provocative behaviors have uniformly supported our model. Results from our review suggest that researchers have been unable to adequately measure impulsivity of attempts and that measures sensitive to episodic planning must be developed to further our understanding of this phenomenon.

  1. Impaired goal-directed behavioural control in human impulsivity

    PubMed Central

    Hogarth, Lee; Chase, Henry W.; Baess, Kathleen

    2010-01-01

    Two dissociable learning processes underlie instrumental behaviour. Whereas goal-directed behaviour is controlled by knowledge of the consequences, habitual behaviour is elicited directly by antecedent Pavlovian stimuli without knowledge of the consequences. Predominance of habitual control is thought to underlie psychopathological conditions associated with corticostriatal abnormalities, such as impulsivity and drug dependence. To explore this claim, smokers were assessed for nicotine dependence, impulsivity, and capacity for goal-directed control over instrumental performance in an outcome devaluation procedure. Reduced goal-directed control was selectively associated with the Motor Impulsivity factor of Barrett's Impulsivity Scale (BIS), which reflects propensity for action without thought. These data support the claim that human impulsivity is marked by impaired use of causal knowledge to make adaptive decisions. The predominance of habit learning may play a role in psychopathological conditions that are associated with trait impulsivity. PMID:21077008

  2. Increased reflection impulsivity in patients with ephedrone induced Parkinsonism

    PubMed Central

    Djamshidian, Atbin; Sanotsky, Yanosh; Matviyenko, Yuriy; O’Sullivan, Sean S.; Sharman, Stephen; Selikhova, Marianna; Fedoryshyn, Ludmyla; Filts, Yuriy; Bearn, Jenny; Lees, Andrew J.; Averbeck, Bruno B.

    2012-01-01

    Aims To examine a syndrome of chronic manganism that occurs in drug addicts in Eastern Europe who use intravenous methcathinone (ephedrone) contaminated with potassium permanganate. The basal ganglia, especially the globus pallidus and the putamen, are damaged irreversibly in many cases. Routine neuropsychological assessment has revealed no cognitive deficits despite widespread abnormalities on brain imaging studies and severe extrapyramidal motor handicap on clinical examination. Design Case control study. Setting Ephedrone patients and patients with opioid dependence were recruited from Lviv, Ukraine. Participants We tested 15 patients with ephedrone induced toxicity, 13 opiate dependent patients, who were receiving opioid replacement therapy and 18 matched healthy volunteers. Measurements The ‘beads task’, an information gathering task to assess reflection impulsivity was used and feedback learning, working memory and risk taking were also assessed. Findings Opiate dependent patients differed from controls on three out of four tasks, whereas ephedrone patients differed from controls on only one task. More specifically both patient groups were more impulsive and made more irrational choices on the beads task than controls (p<0.001). However, ephedrone patients had no deficits in working memory (p>0.1) or risk taking (p>0.1) compared with controls. Opioid dependent patients had significantly worse working memory (p<0.001) and were significantly more risk prone than controls (p=0.002). Conclusions Ephedrone patients may have similar deficits in information gathering and decision making to opiate dependent patients, with preservation of working memory and risk taking. This may reflect specific damage to anterior cingulate- basal ganglia loops. PMID:23228208

  3. Lyapunov Control of Quantum Systems with Impulsive Control Fields

    PubMed Central

    Yang, Wei; Sun, Jitao

    2013-01-01

    We investigate the Lyapunov control of finite-dimensional quantum systems with impulsive control fields, where the studied quantum systems are governed by the Schrödinger equation. By three different Lyapunov functions and the invariant principle of impulsive systems, we study the convergence of quantum systems with impulsive control fields and propose new results for the mentioned quantum systems in the form of sufficient conditions. Two numerical simulations are presented to illustrate the effectiveness of the proposed control method. PMID:23766712

  4. Effects of Acoustic Impulses on the Middle Ear

    DTIC Science & Technology

    2015-10-01

    impulsive noises (impacts and impulses). Keywords: Noise exposure; hearing loss, noise-induced; impulsive noise; reflex ; conditioned response...stated in the approved SOW are: 1. Determine the prevalence of acoustic reflexes to among young people with H-1 hearing status as per Army...Regulation 40-501, Table 7-1. 2. Determine whether reflexive MEMC are pervasive for multiple acoustic and non-acoustic stimuli. 3. Determine whether

  5. Energetic electrons in impulsive solar flares

    NASA Technical Reports Server (NTRS)

    Batchelor, D. A.

    1984-01-01

    A new analysis was made of a thermal flare model proposed by Brown, Melrose, and Spicer (1979) and Smith and Lilliequist (1979). They assumed the source of impulsive hard X-rays to be a plasma at a temperature of order 10 to the 8th power K, initially located at the apex of a coronal arch, and confined by ion-acoustic turbulence in a collisionless conduction front. Such a source would expand at approximately the ion-sound speed, C sub S = square root of (k T sub e/m sub i), until it filled the arch. Brown, Melrose, and Spicer and Smith and Brown (1980) argued that the source assumed in this model would not explain the simultaneous impulsive microwave emission. In contrast, the new results presented herein suggest that this model leads to the development of a quasi-Maxwellian distribution of electrons that explains both the hard X-ray and microwave emissions. This implies that the source sizes can be determined from observations of the optically-thick portions of microwave spectra and the temperatures obtained from associated hard X-ray observations. In this model, the burst emission would rise to a maximum in a time, t sub r, approximately equal to L/c sub s, where L is the half-length of the arch. New observations of these impulsive flare emissions were analyzed herein to test this prediction of the model. Observations made with the Solar Maximum Mission spacecraft and the Bern Radio Observatory are in good agreement with the model.

  6. Adiabatic heating in impulsive solar flares

    NASA Technical Reports Server (NTRS)

    Maetzler, C.; Bai, T.; Crannell, C. J.; Frost, K. J.

    1977-01-01

    The dynamic X-ray spectra of two simple, impulsive solar flares are examined together with H alpha, microwave and meter wave radio observations. X-ray spectra of both events were characteristic of thermal bremsstrahlung from single temperature plasmas. The symmetry between rise and fall was found to hold for the temperature and emission measure. The relationship between temperature and emission measure was that of an adiabatic compression followed by adiabatic expansion; the adiabatic index of 5/3 indicated that the electron distribution remained isotropic. Observations in H alpha provided further evidence for compressive energy transfer.

  7. Antiepileptics for aggression and associated impulsivity

    PubMed Central

    Huband, Nick; Ferriter, Michael; Nathan, Rajan; Jones, Hannah

    2014-01-01

    Background Aggression is a major public health issue and is integral to several mental health disorders. Antiepileptic drugs may reduce aggression by acting on the central nervous system to reduce neuronal hyper-excitability associated with aggression. Objectives To evaluate the efficacy of antiepileptic drugs in reducing aggression and associated impulsivity. Search methods We searched CENTRAL, MEDLINE, EMBASE, CINAHL, PsycINFO, metaRegister of Controlled Trials (mRCT) and ClinicalTrials.gov to April 2009. We also searched Cochrane Schizophrenia Group’s register of trials on aggression, National Research Record and handsearched for studies. Selection criteria Prospective, placebo-controlled trials of antiepileptic drugs taken regularly by individuals with recurrent aggression to reduce the frequency or intensity of aggressive outbursts. Data collection and analysis Three authors independently selected studies and two authors independently extracted data. We calculated standardised mean differences (SMDs), with odds ratios (ORs) for dichotomous data. Main results Fourteen studies with data from 672 participants met the inclusion criteria. Five different antiepileptic drugs were examined. Sodium valproate/divalproex was superior to placebo for outpatient men with recurrent impulsive aggression, for impulsively aggressive adults with cluster B personality disorders, and for youths with conduct disorder, but not for children and adolescents with pervasive developmental disorder. Carbamazepine was superior to placebo in reducing acts of self-directed aggression in women with borderline personality disorder, but not in children with conduct disorder. Oxcarbazepine was superior to placebo for verbal aggression and aggression against objects in adult outpatients. Phenytoin was superior to placebo on the frequency of aggressive acts in male prisoners and in outpatient men including those with personality disorder, but not on the frequency of ‘behavioral incidents’ in

  8. Controller reduction by preserving impulse response energy

    NASA Technical Reports Server (NTRS)

    Craig, Roy R., Jr.; Su, Tzu-Jeng

    1989-01-01

    A model order reduction algorithm based on a Krylov recurrence formulation is developed to reduce order of controllers. The reduced-order controller is obtained by projecting the full-order LQG controller onto a Krylov subspace in which either the controllability or the observability grammian is equal to the identity matrix. The reduced-order controller preserves the impulse response energy of the full-order controller and has a parameter-matching property. Two numerical examples drawn from other controller reduction literature are used to illustrate the efficacy of the proposed reduction algorithm.

  9. The genetic correlation between procrastination and impulsivity.

    PubMed

    Loehlin, John C; Martin, Nicholas G

    2014-12-01

    The reported genetic correlation of 1.0 between the traits of procrastination and impulsivity (Gustavson, D. E., Miyake, A., Hewitt, J. K., & Friedman, N. P. (2014). Psychological Science), which was held to support an evolutionary origin of the relationship between the two traits, was tested in data from two large samples of twins from Australia. A genetic correlation of 0.299 was obtained. It was concluded that, although the presence of a genetic correlation between the two traits was supported, the modest magnitude of the correlation was such as to be consistent with many possible hypotheses, evolutionary and otherwise, about causal relationships between the traits in question.

  10. Association between Impulsivity and Weight Status in a General Population

    PubMed Central

    Bénard, Marc; Camilleri, Géraldine M.; Etilé, Fabrice; Méjean, Caroline; Bellisle, France; Reach, Gérard; Hercberg, Serge; Péneau, Sandrine

    2017-01-01

    The objective of this study is to examine the association between impulsivity and weight status in a large sample of the adult general population in France, and the influence of gender on this relationship. A total of 11,929 men and 39,114 women participating in the NutriNet-Santé cohort were selected in this cross-sectional analysis. The Barratt Impulsiveness Scale (BIS-11) was used to assess impulsivity. Weight and height were self-reported. The association between impulsivity and BMI was estimated using logistic regressions adjusted for socio-demographic and lifestyle factors. Individuals with high impulsivity levels (BIS-11 total score >71) were more likely to be obese (Odds Ratio (OR) = 1.80, 95% Confidence Interval (CI): 1.39, 2.33 in men; OR = 1.30, 95% CI: 1.15, 1.48 in women) compared to individuals in the average range of impulsivity. The strongest associations between impulsivity and obesity were observed in men, where highly impulsive participants were more likely to be class III obese (BMI > 40 kg/m2) (OR = 3.57, 95% CI: 1.86, 6.85). This large sample analysis supports the existence of a relationship between impulsivity and weight status and the importance of psychological factors in the prevention of obesity. PMID:28257032

  11. Dissecting impulsivity and its relationships to drug addictions.

    PubMed

    Jentsch, J David; Ashenhurst, James R; Cervantes, M Catalina; Groman, Stephanie M; James, Alexander S; Pennington, Zachary T

    2014-10-01

    Addictions are often characterized as forms of impulsive behavior. That said, it is often noted that impulsivity is a multidimensional construct, spanning several psychological domains. This review describes the relationship between varieties of impulsivity and addiction-related behaviors, the nature of the causal relationship between the two, and the underlying neurobiological mechanisms that promote impulsive behaviors. We conclude that the available data strongly support the notion that impulsivity is both a risk factor for, and a consequence of, drug and alcohol consumption. While the evidence indicating that subtypes of impulsive behavior are uniquely informative--either biologically or with respect to their relationships to addictions--is convincing, multiple lines of study link distinct subtypes of impulsivity to low dopamine D2 receptor function and perturbed serotonergic transmission, revealing shared mechanisms between the subtypes. Therefore, a common biological framework involving monoaminergic transmitters in key frontostriatal circuits may link multiple forms of impulsivity to drug self-administration and addiction-related behaviors. Further dissection of these relationships is needed before the next phase of genetic and genomic discovery will be able to reveal the biological sources of the vulnerability for addiction indexed by impulsivity.

  12. Eyes wide shopped: shopping situations trigger arousal in impulsive buyers.

    PubMed

    Serfas, Benjamin G; Büttner, Oliver B; Florack, Arnd

    2014-01-01

    The present study proposes arousal as an important mechanism driving buying impulsiveness. We examined the effect of buying impulsiveness on arousal in non-shopping and shopping contexts. In an eye-tracking experiment, we measured pupil dilation while participants viewed and rated pictures of shopping scenes and non-shopping scenes. The results demonstrated that buying impulsiveness is closely associated with arousal as response to viewing pictures of shopping scenes. This pertained for hedonic shopping situations as well as for utilitarian shopping situations. Importantly, the effect did not emerge for non-shopping scenes. Furthermore, we demonstrated that arousal of impulsive buyers is independent from cognitive evaluation of scenes in the pictures.

  13. Genetic association of impulsivity in young adults: a multivariate study

    PubMed Central

    Khadka, S; Narayanan, B; Meda, S A; Gelernter, J; Han, S; Sawyer, B; Aslanzadeh, F; Stevens, M C; Hawkins, K A; Anticevic, A; Potenza, M N; Pearlson, G D

    2014-01-01

    Impulsivity is a heritable, multifaceted construct with clinically relevant links to multiple psychopathologies. We assessed impulsivity in young adult (N~2100) participants in a longitudinal study, using self-report questionnaires and computer-based behavioral tasks. Analysis was restricted to the subset (N=426) who underwent genotyping. Multivariate association between impulsivity measures and single-nucleotide polymorphism data was implemented using parallel independent component analysis (Para-ICA). Pathways associated with multiple genes in components that correlated significantly with impulsivity phenotypes were then identified using a pathway enrichment analysis. Para-ICA revealed two significantly correlated genotype–phenotype component pairs. One impulsivity component included the reward responsiveness subscale and behavioral inhibition scale of the Behavioral-Inhibition System/Behavioral-Activation System scale, and the second impulsivity component included the non-planning subscale of the Barratt Impulsiveness Scale and the Experiential Discounting Task. Pathway analysis identified processes related to neurogenesis, nervous system signal generation/amplification, neurotransmission and immune response. We identified various genes and gene regulatory pathways associated with empirically derived impulsivity components. Our study suggests that gene networks implicated previously in brain development, neurotransmission and immune response are related to impulsive tendencies and behaviors. PMID:25268255

  14. Impulsive control of a financial model [rapid communication

    NASA Astrophysics Data System (ADS)

    Sun, Jitao; Qiao, Fei; Wu, Qidi

    2005-02-01

    In this Letter, several new theorems on the stability of impulsive control systems are presented. These theorem are then used to find the conditions under which an advertising strategy can be asymptotically control to the equilibrium point by using impulsive control. Given the parameters of the financial model and the impulsive control law, an estimation of the upper bound of the impulse interval is given, i.e., number of advert can been decreased (i.e., can decrease cost) for to obtain the equivalent advertising effect.The result is illustrated to be efficient through a numerical example.

  15. The Relationship between Impulsivity and Problem Gambling in Adolescence

    PubMed Central

    Secades-Villa, Roberto; Martínez-Loredo, Victor; Grande-Gosende, Aris; Fernández-Hermida, José R.

    2016-01-01

    Gambling has become one of the most frequently reported addictive behaviors among young people. Understanding risk factors associated with the onset or maintenance of gambling problems in adolescence has implications for its prevention and treatment. The main aim of the present study was to examine the potential relationships between impulsivity and problem gambling in adolescence. Participants were 874 high school students (average age: 15 years old) who were surveyed to provide data on gambling and impulsivity. Self-reported gambling behavior was assessed using the South Oaks Gambling Screen – Revised for Adolescents (SOGS-RA) and impulsivity was measured using the Impulsive Sensation Seeking Questionnaire (ZKPQ), the Barratt Impulsiveness Scale (BIS-11-A), and a delay discounting task. The data were analyzed using both a prospective-longitudinal and a cross-sectional design. In the longitudinal analyses, results showed that the impulsivity subscale of the ZKPQ increased the risk of problem gambling (p = 0.003). In the cross-sectional analyses, all the impulsivity measures were higher in at-risk/problem gamblers than in non-problem gamblers (p = 0.04; 0.03; and 0.01, respectively). These findings further support the relationship between impulsivity and gambling in adolescence. Moreover, our findings suggest a bidirectional relationship between impulsivity and problem gambling in adolescence. These results have consequences for the development of prevention and treatment programs for adolescents with gambling problems. PMID:28008322

  16. A centre-triggered magnesium fuelled cathodic arc thruster uses sublimation to deliver a record high specific impulse

    NASA Astrophysics Data System (ADS)

    Neumann, Patrick R. C.; Bilek, Marcela; McKenzie, David R.

    2016-08-01

    The cathodic arc is a high current, low voltage discharge that operates in vacuum and provides a stream of highly ionised plasma from a solid conducting cathode. The high ion velocities, together with the high ionisation fraction and the quasineutrality of the exhaust stream, make the cathodic arc an attractive plasma source for spacecraft propulsion applications. The specific impulse of the cathodic arc thruster is substantially increased when the emission of neutral species is reduced. Here, we demonstrate a reduction of neutral emission by exploiting sublimation in cathode spots and enhanced ionisation of the plasma in short, high-current pulses. This, combined with the enhanced directionality due to the efficient erosion profiles created by centre-triggering, substantially increases the specific impulse. We present experimentally measured specific impulses and jet power efficiencies for titanium and magnesium fuels. Our Mg fuelled source provides the highest reported specific impulse for a gridless ion thruster and is competitive with all flight rated ion thrusters. We present a model based on cathode sublimation and melting at the cathodic arc spot explaining the outstanding performance of the Mg fuelled source. A further significant advantage of an Mg-fuelled thruster is the abundance of Mg in asteroidal material and in space junk, providing an opportunity for utilising these resources in space.

  17. Impulse source versus dodecahedral loudspeaker for measuring parameters derived from the impulse response in room acoustics.

    PubMed

    San Martín, Ricardo; Arana, Miguel; Machín, Jorge; Arregui, Abel

    2013-07-01

    This study investigates the performance of dodecahedral and impulse sources when measuring acoustic parameters in enclosures according to ISO 3382-1 [Acoustics-Measurement of room acoustic parameters. Part 1: Performance spaces (International Organization for Standardization, Geneva, Switzerland, 2009)]. In general, methods using speakers as a sound source are limited by their frequency response and directivity. On the other hand, getting impulse responses from impulse sources typically involves a lack of repeatability, and it is usually necessary to average several measurements for each position. Through experiments in different auditoriums that recreate typical situations in which the measurement standard is applied, it is found that using impulse sources leads to greater variation in the results, especially at low frequencies. However, this prevents subsequent dispersions due to variables that this technique does not require, such as the orientation of the emitting source. These dispersions may be relevant at high frequencies exceeding the established tolerance criteria for certain parameters. Finally, a new descriptor for dodecahedral sources reflecting the influence their lack of omnidirectionality produces on measuring acoustic parameters is proposed.

  18. Impulsivity and the sexes: measurement and structural invariance of the UPPS-P Impulsive Behavior Scale.

    PubMed

    Cyders, Melissa A

    2013-02-01

    Before it is possible to test whether men and women differ in impulsivity, it is necessary to evaluate whether impulsivity measures are invariant across sex. The UPPS-P Impulsive Behavior Scale (negative urgency, lack of premeditation, lack of perseverance, and sensation seeking, with added subscale of positive urgency) is one measure of five dispositions toward rash action that has shown to have robust and clinically useful relationships among risk-taking outcomes. In the current research, the author examined (a) the psychometric measurement invariance of the UPPS-P across sex, (b) the scale's structural invariance across sex, and (c) whether the five impulsivity traits differentially relate to risk outcomes as a function of sex. In a sample of 1,372 undergraduates, the author found evidence for measurement and invariance across sex: Thus, comparisons of men and women on the UPPS-P can be considered valid. Additionally, although males tend to report higher levels of sensation seeking and positive urgency (and possibly lack of perseverance), the relationships between the UPPS-P traits and risk outcomes were generally invariant across sex. The UPPS-P appears to function comparably across males and females, and mean differences on this scale between the sexes can be thought to reflect trait-level differences.

  19. Trait Impulsivity and Anhedonia: Two Gateways for the Development of Impulse Control Disorders in Parkinson's Disease?

    PubMed

    Houeto, Jean-Luc; Magnard, Robin; Dalley, Jeffrey W; Belin, David; Carnicella, Sebastien

    2016-01-01

    Apathy and impulsivity are two major comorbid syndromes of Parkinson's disease (PD) that may represent two extremes of a behavioral spectrum modulated by dopamine-dependent processes. PD is characterized by a progressive loss of dopaminergic neurons in the substantia nigra pars compacta to which are attributed the cardinal motor symptoms of the disorder. Dopamine replacement therapy (DRT), used widely to treat these motor symptoms, is often associated with deficits in hedonic processing and motivation, including apathy and depression, as well as impulse control disorders (ICDs). ICDs comprise pathological gambling, hypersexuality, compulsive shopping, binge eating, compulsive overuse of dopaminergic medication, and punding. More frequently observed in males with early onset PD, ICDs are associated not only with comorbid affective symptoms, such as depression and anxiety, but also with behavioral traits, such as novelty seeking and impulsivity, as well as with personal or familial history of alcohol use. This constellation of associated risk factors highlights the importance of inter-individual differences in the vulnerability to develop comorbid psychiatric disorders in PD patients. Additionally, withdrawal from DRT in patients with ICDs frequently unmasks a severe apathetic state, suggesting that apathy and ICDs may be caused by overlapping neurobiological mechanisms within the cortico-striato-thalamo-cortical networks. We suggest that altered hedonic and impulse control processes represent distinct prodromal substrates for the development of these psychiatric symptoms, the etiopathogenic mechanisms of which remain unknown. Specifically, we argue that deficits in hedonic and motivational states and impulse control are mediated by overlapping, yet dissociable, neural mechanisms that differentially interact with DRT to promote the emergence of ICDs in vulnerable individuals. Thus, we provide a novel heuristic framework for basic and clinical research to better

  20. Static and Impulsive Models of Solar Active Regions

    NASA Technical Reports Server (NTRS)

    Patsourakos, S.; Klimchuk, James A.

    2008-01-01

    The physical modeling of active regions (ARs) and of the global coronal is receiving increasing interest lately. Recent attempts to model ARs using static equilibrium models were quite successful in reproducing AR images of hot soft X-ray (SXR) loops. They however failed to predict the bright EUV warm loops permeating ARs: the synthetic images were dominated by intense footpoint emission. We demonstrate that this failure is due to the very weak dependence of loop temperature on loop length which cannot simultaneously account for both hot and warm loops in the same AR. We then consider time-dependent AR models based on nanoflare heating. We demonstrate that such models can simultaneously reproduce EUV and SXR loops in ARs. Moreover, they predict radial intensity variations consistent with the localized core and extended emissions in SXR and EUV AR observations respectively. We finally show how the AR morphology can be used as a gauge of the properties (duration, energy, spatial dependence, repetition time) of the impulsive heating.

  1. Stable glow discharge detector

    DOEpatents

    Koo, Jackson C.; Yu, Conrad M.

    2004-05-18

    A highly sensitive electronic ion cell for the measurement of trace elements in He carrier gas which involves glow discharge. A constant wave (CW) stable glow discharge detector which is controlled through a biased resistor, can detect the change of electron density caused by impurities in the He carrier gas by many orders of magnitude larger than that caused by direct ionization or electron capture. The stable glow discharge detector utilizes a floating pseudo-electrode to form a probe in or near the plasma and a solid rod electrode. By using this probe, the large variation of electron density due to trace amounts of impurities can be directly measured. The solid rod electrode provides greater stability and thus easier alignment.

  2. Antarctic subglacial lake discharges

    NASA Astrophysics Data System (ADS)

    Pattyn, Frank

    Antarctic subglacial lakes were long time supposed to be relatively closed and stable environments with long residence times and slow circulations. This view has recently been challenged with evidence of active subglacial lake discharge underneath the Antarctic ice sheet. Satellite altimetry observations witnessed rapid changes in surface elevation across subglacial lakes over periods ranging from several months to more than a year, which were interpreted as subglacial lake discharge and subsequent lake filling, and which seem to be a common and widespread feature. Such discharges are comparable to jökulhlaups and can be modeled that way using the Nye-Röthlisberger theory. Considering the ice at the base of the ice sheet at pressure melting point, subglacial conduits are sustainable over periods of more than a year and over distances of several hundreds of kilometers. Coupling of an ice sheet model to a subglacial lake system demonstrated that small changes in surface slope are sufficient to start and sustain episodic subglacial drainage events on decadal time scales. Therefore, lake discharge may well be a common feature of the subglacial hydrological system, influencing the behavior of large ice sheets, especially when subglacial lakes are perched at or near the onset of large outlet glaciers and ice streams. While most of the observed discharge events are relatively small (101-102 m3 s-1), evidence for larger subglacial discharges is found in ice free areas bordering Antarctica, and witnessing subglacial floods of more than 106 m3 s-1 that occurred during the middle Miocene.

  3. Impulse Propagation in Disordered Hertzian Chains

    NASA Astrophysics Data System (ADS)

    Manciu, Marian; Sen, Surajit; Hurd, Alan J.

    2000-03-01

    It was shown by Nesterenko [1] that an impulse initiated at an end of a chain of elastic grains in mutual contact, i.e., interacting via the nonlinear Hertz potential, travels as a soliton-like object. Recent theoretical [2], experimental [3] and numerical studies [4] have validated his findings. In the presentation we shall examine the propagation of an impulse in an imperfect system that is characterized by grains composed of different elastic materials, different sizes, shapes and velocity-dependent friction. Our study shows that even in the presence of considerable disorder, most of the energy still travels as a weakly dispersive bundle of energy. According to our calculations, the amplitude, position and geometry of the leading pulse are related to chain disorder via simple scaling laws. We shall comment upon the inverse problem of determining the material properties by studying the pulse propagation, with many potential applications. [1] V.F. Nesterenko, J Appl Mech Tech Phys 5, 733 (1983) [2] S. Sen and M. Manciu, Physica A 268, 644 (1999); A. Chatterjee, Phys Rev E 59, 5912 (1999) [3] C. Coste, E. Falcon and S. Fauve, Phys Rev E 56, 6104 (1997); E.J. Hinch and S. Saint-Jean, Proc R Soc A 455, 3201 (1999) [4] M. Manciu, V. Tehan and S. Sen, Chaos (in press)

  4. Design and construction of an impulse turbine

    NASA Astrophysics Data System (ADS)

    Hernández, E.

    2013-11-01

    Impulse turbine has been constructed to be used in the program of Hydraulic Machines, Faculty of Mechanical Engineering at the Universidad Pontificia Bolivariana, sede Bucaramanga. For construction of the impulse turbine (Pelton) detailed plans were drawn up taking into account the design and implementation of the fundamental equations of hydraulic turbomachinery. From the experimental data found maximum mechanical efficiency of 0.6 ± 0.03 for a water flow of 2.1 l/s. The maximum overall efficiency was 0.23 ± 0.02 for a water flow of 0.83 l/s. The design parameter used was a power of 1 kW, as flow regulator built a needle type regulator, which performed well, the model of the bucket or vane is built on a machine type CNC (Computer Numerical Control). For the construction of the impeller and blades was used aluminium because of chemical and physical characteristics and the casing was manufactured in acrylic.

  5. Rock Directed Breaking Under the Impulse Load

    NASA Astrophysics Data System (ADS)

    Khomeriki, Sergo; Mataradze, Edgar; Chikhradze, Nikoloz; Losaberidze, Marine; Khomeriki, Davit; Shatberashvili, Grigol

    2016-10-01

    In the work the problem of directed chipping of facing stone material by means of managing of explosion process is considered. The technology of the mining of decorative stone by the use of explosion energy means the very rapid transfer of potential energy of elastic deformations to kinetic energy. As a result, the explosion impulse, in the expanse of the inertia of rock massive, does not cause the increase of existing cracks. In the course of explosion, the shock wave is propagated by ultrasonic velocity and in this case the medium parameters (pressure, density, temperature, velocity) increase in spurts. In spite of this fact the all three conservation laws of mechanics remain valid on basis of three laws the equations are derived by which the parameters of shock wave may be defined by means of the rock physical-mechanical properties. The load on the body volume at breaking under explosion acts over very small period of the time. Therefore, stressed-deformed state of the rock was studied when the impulse load acts on the boundary. It was considered that the mining of the blocks of facing stone is performed from the hard rocks. This means that the breaking proceeds in the zone of elastic deformation. In the conditions of mentioned assumptions, the expression of the stress tensor and displacement of vector components initiated by stressed-deformed state in the rock are written.

  6. Low cost impulse compatible wideband antenna

    DOEpatents

    Rosenbury, Erwin T.; Burke, Gerald J.; Nelson, Scott D.; Stever, Robert D.; Governo, George K.; Mullenhoff, Donald J.

    2002-01-01

    An antenna apparatus and method for building the antenna is disclosed. Impulse signals travel through a feed point of the antenna with respect to a ground plane. A geometric fin structure is connected to the feed point, and through a termination resistance to the ground plane. A geometric ridge structure connected to the ground is positioned with respect to the fin in order to receive and radiate electromagnetic energy from the impulse signal at a predetermined impedance and over a predetermined set of frequencies. The fin and ridge can be either a wire or a planar surface. The fin and ridge may be disposed within a radiation cavity such as a horn. The radiation cavity is constructed of stamped and etched metal sheets bent and then soldered together. The fin and ridge are also formed from metal sheets or wires. The fin is attached to the feed point and then to the cavity through a termination resistance. The ridge is attached to the cavity and disposed with respect to the fin in order to achieve a particular set of antenna characteristics.

  7. Mixed Gaussian-Impulse Noise Image Restoration Via Total Variation

    DTIC Science & Technology

    2012-05-01

    pp. 402–407. [12] L. Rudin , S. Osher, and E. Fatemi, “Nonlinear total vari- ation based noise removal algorithms.,” Physica D. Non- lin. Phenomena...variation regularization in positron emission tomography,” UCLA CAM Report 98-48, 1998, CAM Report 98-48, UCLA. [16] S. Osher, N. Paragios, L. Rudin , and P

  8. The role of serotonin in impulsive aggression, suicide, and homicide in adolescents and adults: a literature review.

    PubMed

    Glick, Amy R

    2015-05-01

    This is a literature review discussing previous studies on the associations between impulsive aggression and the serotonergic system in adults, adolescents, and children. The review demonstrates that there is a clear association between low cerebrospinal fluid serotonin and impulsive aggression. However, studies on neurotransmitter receptor profiles, functional imaging, genetics, and epigenetics reviewed in this article suggest a more complicated picture that includes consideration of gene vs. environment in the evaluation of risk. Serotonin supplementation studies suggest that selective serotonin reuptake inhibitors may reduce impulsive aggression in some adults but are less effective in adults with pathological aggression and also in children and adolescents. Child and adolescent studies are less conclusive, in part due to the heterogeneous physiologic and psychosocial changes occurring over the course of development. The author thus concludes that psychiatrists can reduce risk in these special patient populations by creating safer environments in the form of changes in policy and increased support services.

  9. Electric field step in air gap streamer discharges

    SciTech Connect

    Zeng Rong; Zhuang Chijie; Yu Zhanqing; Li Zhizhao; Geng Yinan

    2011-11-28

    Electric field (E-field) in air gap streamer discharges under positive lightning impulse was measured by specifically developed integrated electro-optic sensors. An E-field step phenomenon was observed. The E-field firstly agreed with the Laplace field, then suddenly increased with a rise time of {mu}s. The occurrence probability of this phenomenon increased as the applied voltage increased. The discharge current waveforms and photos taken by a fast camera prove the E-field step was caused by the space net charge. From the E-step rise time and the corona area range, the average electron drift speed under the experiment situation was estimated about 0.2 x 10{sup 6} - 0.6x 10{sup 6} m/s.

  10. Effect of Airflows on Repetitive Nanosecond Volume Discharges

    NASA Astrophysics Data System (ADS)

    Tang, Jingfeng; Wei, Liqiu; Huo, Yuxin; Song, Jian; Yu, Daren; Zhang, Chaohai

    2016-03-01

    Atmospheric pressure discharges excited by repetitive nanosecond pulses have attracted significant attention for various applications. In this paper, a plate-plate discharge with airflows is excited by a repetitive nanosecond pulse generator. Under different experiment conditions, the applied voltages, discharge currents, and discharge images are recorded. The plasma images presented here indicate that the volume discharge modes vary with airflow speeds, and a diffuse and homogeneous volume discharge occurs at the speed of more than 35 m/s. The role of airflows provides different effects on the 2-stage pulse discharges. The 1st pulse currents nearly maintain consistency for different airflow speeds. However, the 2nd pulse current has a change trend of first decreasing and then rapidly increasing, and the value difference for 2nd pulse currents is about 20 A under different airflows. In addition, the experimental results are discussed according to the electrical parameters and discharge images. supported by National Natural Science Foundation of China (Nos. 51006027, 51437002, and 51477035)

  11. The pressure impulse of a laser-induced underwater shock wave

    NASA Astrophysics Data System (ADS)

    Tagawa, Yoshiyuki; Yamamoto, Shota; Hayasaka, Keisuke; Kameda, Masaharu

    2016-11-01

    We investigate the pressure impulse, the time integral of pressure evolution, of a laser-induced underwater shock wave. We simultaneously observe plasma formation, shock-wave expansion, and pressure in water using a combined measurement system that obtains high-resolution nanosecond-order image sequences. Remarkably, pressure impulse is found to distribute symmetrically for a wide range of experimental parameters even when the shock waves are emitted from an elongated plasma. In contrast, distribution of pressure peak is found to be non-spherically-symmetric. We rationalize aforementioned results by considering the structure of the underwater shock wave as a collection of multiple spherical shock waves originated from point-like plasmas in an elongated region. This work was supported by JSPS KAKANHI Grant Number JP26709007.

  12. Dynamical relations for left ventricular ejection - Flow rate, momentum, force and impulse

    NASA Technical Reports Server (NTRS)

    Back, L. H.; Selzer, R. H.; Gordon, D. G.; Ledbetter, D. C.; Crawford, D. W.

    1984-01-01

    An investigation was carried out to quantitatively evaluate left ventricular volume flow rate, momentum, force and impulse derived from application of conservation principles for mass and momentum of blood within the ventricle during the ejection phase. An automated digital image processing system was developed and applied to left ventricular angiograms which are computer processed and analyzed frame by frame to determine the dynamical relations by numerical methods. The initial experience with force and impulse has indicated that neither quantity seemed to be a sensitive indicator of coronary artery disease as evaluated by qualitative angiography for the particular patient group studied. Utilization of the dynamical relations in evaluating human left ventricular performance requires improved means of measurement and interpretation of clinical studies.

  13. Longitudinal discharge laser baffles

    DOEpatents

    Warner, B.E.; Ault, E.R.

    1994-06-07

    The IR baffles placed between the window and the electrode of a longitudinal discharge laser improve laser performance by intercepting off-axis IR radiation from the laser and in doing so reduce window heating and subsequent optical distortion of the laser beam. 1 fig.

  14. Longitudinal discharge laser baffles

    DOEpatents

    Warner, Bruce E.; Ault, Earl R.

    1994-01-01

    The IR baffles placed between the window and the electrode of a longitudinal discharge laser improve laser performance by intercepting off-axis IR radiation from the laser and in doing so reduce window heating and subsequent optical distortion of the laser beam.

  15. Sex Differences in Impulsivity: A Meta-Analysis

    ERIC Educational Resources Information Center

    Cross, Catharine P.; Copping, Lee T.; Campbell, Anne

    2011-01-01

    Men are overrepresented in socially problematic behaviors, such as aggression and criminal behavior, which have been linked to impulsivity. Our review of impulsivity is organized around the tripartite theoretical distinction between reward hypersensitivity, punishment hyposensitivity, and inadequate effortful control. Drawing on evolutionary,…

  16. Impulsivity in internet addiction: a comparison with pathological gambling.

    PubMed

    Lee, Hae Woo; Choi, Jung-Seok; Shin, Young-Chul; Lee, Jun-Young; Jung, Hee Yeon; Kwon, Jun Soo

    2012-07-01

    Internet addiction has been considered to be associated with poor impulse control. The aim of this study is to compare the trait impulsivity of those suffering from Internet addiction with that of individuals suffering from pathological gambling. Twenty-seven patients diagnosed with Internet addiction (age: 24.78±4.37 years), 27 patients diagnosed with pathological gambling (age: 25.67±3.97 years), and 27 healthy controls (age: 25.33±2.79 years) were enrolled in this study. All patients were men seeking treatment. Trait impulsivity and the severity of the Internet addiction and pathological gambling were measured by the Barratt Impulsiveness Scale-11, the Young's Internet Addiction Test, and the South Oaks Gambling Screen, respectively. The Beck Depression Inventory and the Beck Anxiety Inventory were also administered to all subjects. Our results show that those suffering from Internet addiction showed increased levels of trait impulsivity which were comparable to those of patients diagnosed with pathological gambling. Additionally, the severity of Internet addiction was positively correlated with the level of trait impulsivity in patients with Internet addiction. These results state that Internet addiction can be conceptualized as an impulse control disorder and that trait impulsivity is a marker for vulnerability to Internet addiction.

  17. Domain-Specific Impulsivity in School-Age Children

    ERIC Educational Resources Information Center

    Tsukayama, Eli; Duckworth, Angela Lee; Kim, Betty

    2013-01-01

    Impulsivity is a salient individual difference in children with well-established predictive validity for life outcomes. The current investigation proposes that impulsive behaviors vary systematically by domain. In a series of studies with ethnically and socioeconomically diverse samples of middle school students, we find that schoolwork-related…

  18. Impulsivity in College Students with and without ADHD

    ERIC Educational Resources Information Center

    Miller, Jessica A.

    2010-01-01

    Impulsivity is the cardinal symptom of ADHD. It is estimated that ADHD is present in eighteen percent of children and in four percent of adults. The present study repeats and extends a previous study (Gray, Breier, Foorman, & Fletcher, 2002) that measured impulsivity in adolescents with and without ADHD, which found higher false alarm rates…

  19. Periodic solutions for ordinary differential equations with sublinear impulsive effects

    NASA Astrophysics Data System (ADS)

    Qian, Dingbian; Li, Xinyu

    2005-03-01

    The continuation method of topological degree is used to investigate the existence of periodic solutions for ordinary differential equations with sublinear impulsive effects. The applications of the abstract approach include the generalizations of some classical nonresonance theorem for impulsive equations, for instance, the existence theorem for asymptotically positively homogeneous differential systems and the existence theorem for second order equations with Landesman-Lazer conditions.

  20. Individual differences in impulsivity predict anticipatory eye movements.

    PubMed

    Cirilli, Laetitia; de Timary, Philippe; Lefèvre, Phillipe; Missal, Marcus

    2011-01-01

    Impulsivity is the tendency to act without forethought. It is a personality trait commonly used in the diagnosis of many psychiatric diseases. In clinical practice, impulsivity is estimated using written questionnaires. However, answers to questions might be subject to personal biases and misinterpretations. In order to alleviate this problem, eye movements could be used to study differences in decision processes related to impulsivity. Therefore, we investigated correlations between impulsivity scores obtained with a questionnaire in healthy subjects and characteristics of their anticipatory eye movements in a simple smooth pursuit task. Healthy subjects were asked to answer the UPPS questionnaire (Urgency Premeditation Perseverance and Sensation seeking Impulsive Behavior scale), which distinguishes four independent dimensions of impulsivity: Urgency, lack of Premeditation, lack of Perseverance, and Sensation seeking. The same subjects took part in an oculomotor task that consisted of pursuing a target that moved in a predictable direction. This task reliably evoked anticipatory saccades and smooth eye movements. We found that eye movement characteristics such as latency and velocity were significantly correlated with UPPS scores. The specific correlations between distinct UPPS factors and oculomotor anticipation parameters support the validity of the UPPS construct and corroborate neurobiological explanations for impulsivity. We suggest that the oculomotor approach of impulsivity put forth in the present study could help bridge the gap between psychiatry and physiology.

  1. Spectral analysis of impulse noise for hearing conservation purposes

    SciTech Connect

    Stevin, G.O.

    1982-12-01

    Damage-risk criteria for impulse noise does not presently take the spectrum of the impulse into account; however, it is known that the human auditory system is spectrally tuned. The present paper advocates the extension to impulse noise of the noise dose concept which is widely used for continuous noise. This approach is based upon sound exposure instead of sound pressure. An A-weighting filter or an octave band analysis can then be used to take the spectral content of the impulses into account. The equipment needed for applying these procedures for impulse noise is an integrating sound level meter or a digital Fourier processor. Generalized spectral methods have been evaluated by means of an impulse simulation applied to a mathematical model of the human hearing mechanism. The results of this simulation agree with the most recent experiments on impulse noise and fully support the proposed rating methods. This conclusion must be emphasized as it leads the derivation of a uniform procedure for predicting loudness and damage risk for hearing which is applicable for continuous noise as well as for impulse noise.

  2. 33 CFR 183.586 - Pressure impulse test.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 2 2013-07-01 2013-07-01 false Pressure impulse test. 183.586...) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Fuel Systems Tests § 183.586 Pressure impulse test. A fuel... pressure test under § 183.580. (b) If the tank is non-metallic, fill it to capacity with a gasoline...

  3. Optimum Three Impulse Trajectory Generator with Patched Conic Trajectory Model

    NASA Technical Reports Server (NTRS)

    Payne, M. H.; Pines, S.; Horsewood, J. L.

    1972-01-01

    Optimal multi-impulse trajectories were investigated as a nominal about which asymptotic expansion was used to obtain approximations of optimal low thrust trajectories. The work consisted of the analysis and description of an optimal 3-impulse trajectory program. A patched-conic trajectory model was specifically designed for compatibility with the subsequent addition of the low thrust expansion approximation.

  4. Causal impulse response for circular sources in viscous media

    PubMed Central

    Kelly, James F.; McGough, Robert J.

    2008-01-01

    The causal impulse response of the velocity potential for the Stokes wave equation is derived for calculations of transient velocity potential fields generated by circular pistons in viscous media. The causal Green’s function is numerically verified using the material impulse response function approach. The causal, lossy impulse response for a baffled circular piston is then calculated within the near field and the far field regions using expressions previously derived for the fast near field method. Transient velocity potential fields in viscous media are computed with the causal, lossy impulse response and compared to results obtained with the lossless impulse response. The numerical error in the computed velocity potential field is quantitatively analyzed for a range of viscous relaxation times and piston radii. Results show that the largest errors are generated in locations near the piston face and for large relaxation times, and errors are relatively small otherwise. Unlike previous frequency-domain methods that require numerical inverse Fourier transforms for the evaluation of the lossy impulse response, the present approach calculates the lossy impulse response directly in the time domain. The results indicate that this causal impulse response is ideal for time-domain calculations that simultaneously account for diffraction and quadratic frequency-dependent attenuation in viscous media. PMID:18397018

  5. Individual Differences in Impulsive Choice and Timing in Rats

    ERIC Educational Resources Information Center

    Galtress, Tiffany; Garcia, Ana; Kirkpatrick, Kimberly

    2012-01-01

    Individual differences in impulsive choice behavior have been linked to a variety of behavioral problems including substance abuse, smoking, gambling, and poor financial decision-making. Given the potential importance of individual differences in impulsive choice as a predictor of behavioral problems, the present study sought to measure the extent…

  6. Choice impulsivity: Definitions, measurement issues, and clinical implications.

    PubMed

    Hamilton, Kristen R; Mitchell, Marci R; Wing, Victoria C; Balodis, Iris M; Bickel, Warren K; Fillmore, Mark; Lane, Scott D; Lejuez, C W; Littlefield, Andrew K; Luijten, Maartje; Mathias, Charles W; Mitchell, Suzanne H; Napier, T Celeste; Reynolds, Brady; Schütz, Christian G; Setlow, Barry; Sher, Kenneth J; Swann, Alan C; Tedford, Stephanie E; White, Melanie J; Winstanley, Catharine A; Yi, Richard; Potenza, Marc N; Moeller, F Gerard

    2015-04-01

    Impulsivity critically relates to many psychiatric disorders. Given the multifaceted construct that impulsivity represents, defining core aspects of impulsivity is vital for the assessment and understanding of clinical conditions. Choice impulsivity (CI), involving the preferential selection of smaller sooner rewards over larger later rewards, represents one important type of impulsivity. The International Society for Research on Impulsivity (InSRI) convened to discuss the definition and assessment of CI and provide recommendations regarding measurement across species. Commonly used preclinical and clinical CI behavioral tasks are described, and considerations for each task are provided to guide CI task selection. Differences in assessment of CI (self-report, behavioral) and calculating CI indices (e.g., area-under-the-curve, indifference point, and steepness of discounting curve) are discussed along with properties of specific behavioral tasks used in preclinical and clinical settings. The InSRI group recommends inclusion of measures of CI in human studies examining impulsivity. Animal studies examining impulsivity should also include assessments of CI and these measures should be harmonized in accordance with human studies of the disorders being modeled in the preclinical investigations. The choice of specific CI measures to be included should be based on the goals of the study and existing preclinical and clinical literature using established CI measures.

  7. Designing an electro-impulse de-icing system

    NASA Technical Reports Server (NTRS)

    Zumwalt, G. W.; Friedberg, R. A.

    1986-01-01

    Basic principles and parameters for a system to deice aircraft with electromagnetic impulses are described. The physical basis for deicing by such impulses is explained, and the requirements involved in the electrodynamic design, structural dynamic design, and system design are discussed. Some manufacturing and testing problems and techniques are described.

  8. Temperament and Character Dimensions: Correlates of Impulsivity in Morphine Addicts

    PubMed Central

    Abassi, Moslem; Abolghasemi, Abbas

    2015-01-01

    Background: Given the role of temperament and character dimensions on impulsivity in addicts, the purpose of this study was to temperament and character dimensions: correlates of impulsivity in morphine addicts. Objectives: The aim of this study was to determine and verify the association of temperament and character dimensions with impulsivity in morphine addicts. Patients and Methods: The research method was descriptive and correlational. The study sample consisted of 120 morphine addicts referred to drug addiction treatment centers in Ardabil city in 2013. The participants were selected through convenience sampling method from 5 centers. We used impulsivity scale as well as temperament and character inventory to collect data. Results: The results showed that significant relationship existed between impulsivity and characteristics such as novelty seeking, harm avoidance, reward dependence, persistence, self-directedness, and cooperativeness, while no significant relationship between impulsivity and self-transcendence was observed. The results of the multiple regression analysis showed that 47% of the impulsivity variance was explained by temperament and character dimensions. Conclusions: These findings suggest that temperament and character dimensions are associated with impulsivity. The findings also have important implications for prevention, pathology, and treatment in the morphine addicts. PMID:26870706

  9. [Impulsivity and decision making in alcohol-addicted individuals].

    PubMed

    Kałwa, Agnieszka

    2013-01-01

    Decision making processes are the research problem, that has been increasingly undertaken. Alcohol addiction is a disease associated with unfavorable decision making, in spite of its negative consequences. Impulsivity plays an important role in alcoholics' decision making. It can be understood in terms of behavioral and/or cognitive flexibility disorders, that manifest in cognitive function disorders, making it difficult or even impossible to quickly and adequately assess the situation and to adjust behavior according to its requirements.. Neurobiological and genetic research indicate the existing relationship between impulsivity and certain genetic predisposition. In alcohol addicts, impulsivity can be understood also in terms of specific personality traits, e.g. novelty seeking according to the theory of Cloninger. Although the concept of impulsivity itself has been the main topic of many studies, not many of them concern also decision making processes. In studies concerning alcoholics' decision making, the relationship between this processes and behavioral impulsivity defined in many different ways, has been noticed. Some of these works define unfavorable decision making processes itself as a feature of impulsivity. Based on the results of theoretical works and research studies, it seems that it would be worth to define more precisely the concept of impulsivity, in order to determine its effect on decision making. The assessment of whether - and to what extent - the two variables (impulsivity and decision making) can be considered as separate should also be taken into account.

  10. The effects of heroin administration and drug cues on impulsivity.

    PubMed

    Jones, Jermaine D; Vadhan, Nehal P; Luba, Rachel R; Comer, Sandra D

    2016-08-01

    Drug addiction is a chronic relapsing disorder characterized by compulsive drug seeking and continued use despite negative consequences. Behavioral impulsivity is a strong predictor of the initiation and maintenance of drug addiction. Preclinical data suggest that heroin may exacerbate impulsive characteristics in an individual but this has yet to be assessed in clinical samples. The current secondary data analysis sought to investigate the effects of heroin on impulsivity along with the effects of exposure to drug cues. Using the current data set, we also tentatively assessed the etiological relationship between impulsivity and heroin abuse. Sixteen heroin-dependent participants were recruited to complete Immediate Memory Task/Delayed Memory Task (IMT/DMT) and GoStop tasks following repeated heroin administration, following acute heroin administration, and following a drug cue exposure session. Four preceding days of active heroin availability, compared to four preceding days of placebo drug availability, increased impulsivity assessed using the IMT and DMT. Presentation of drug cues similarly acted to increase impulsivity assessments on all three tasks. It also appears that heavier users were more susceptible to the influence of drug cues on impulsivity. The present study represents a step toward a more comprehensive understanding of the interaction between opioid abuse and impulsivity. A better understanding of these factors could provide critical insight into the maintenance of heroin use and relapse.

  11. Validity of proposed DSM-5 ADHD impulsivity symptoms in children.

    PubMed

    Ünsel Bolat, Gül; Ercan, Eyüp Sabri; Salum, Giovanni Abrahão; Bilaç, Öznur; Massuti, Rafael; Uysal Özaslan, Taciser; Bolat, Hilmi; Rohde, Luis Augusto

    2016-10-01

    The American Psychiatric Association (APA) working group on Attention-Deficit/Hyperactivity Disorder (ADHD) proposed the inclusion of four new impulsivity symptoms. However, they were not included in DSM-5 due to the lack of sufficient evidence. The aim of this study is to investigate the performance of the proposed four ADHD impulsivity symptoms with respect to: (a) ADHD factor structure; (b) performance in predicting clinical impairment; (c) specificity for ADHD diagnosis and (d) best symptomatic threshold to predict clinical impairment. The sample comprised 416 children (31 ADHD subjects according to both DSM-IV and proposed DSM-5, 20 ADHD subjects according to just one diagnostic system and 365 controls) from 12 schools. Diagnoses were derived using semi-structured interviews and ADHD rating scales. Results from confirmatory factor analysis indicate that addition of the four new impulsivity items provided a slightly better factor structure if compared to models including only 18 items. Regression analyses showed that only one of the new impulsivity symptoms (impatient) was part of the list of best predictors of impairment. None of the four new impulsivity items was specifically associated with ADHD diagnosis. The best cutoff point in the hyperactivity/impulsivity dimension for predicting impairment did not change significantly. Overall, our findings suggest that the determination on how to best capture impulsivity dimension as part of the ADHD construct needs more investigation and that there is not enough evidence to include these four assessed impulsivity symptoms as part of the ADHD criteria.

  12. Choice Impulsivity: Definitions, Measurement Issues, and Clinical Implications

    PubMed Central

    Hamilton, Kristen R.; Mitchell, Marci R.; Wing, Victoria C.; Balodis, Iris M.; Bickel, Warren K.; Fillmore, Mark; Lane, Scott D.; Lejuez, C. W.; Littlefield, Andrew K.; Luijten, Maartje; Mathias, Charles W.; Mitchell, Suzanne H.; Napier, T. Celeste; Reynolds, Brady; Schütz, Christian G.; Setlow, Barry; Sher, Kenneth J.; Swann, Alan C.; Tedford, Stephanie E.; White, Melanie J.; Winstanley, Catharine A.; Yi, Richard; Potenza, Marc N.; Moeller, F. Gerard

    2015-01-01

    Background Impulsivity critically relates to many psychiatric disorders. Given the multi-faceted construct that impulsivity represents, defining core aspects of impulsivity is vital for the assessment and understanding of clinical conditions. Choice impulsivity (CI), involving the preferential selection of smaller sooner rewards over larger later rewards, represents one important type of impulsivity. Method The International Society for Research on Impulsivity (InSRI) convened to discuss the definition and assessment of CI and provide recommendations regarding measurement across species. Results Commonly used preclinical and clinical CI behavioral tasks are described, and considerations for each task are provided to guide CI task selection. Differences in assessment of CI (self-report, behavioral) and calculating CI indices (e.g., area-under-the-curve, indifference point, steepness of discounting curve) are discussed along with properties of specific behavioral tasks used in preclinical and clinical settings. Conclusions The InSRI group recommends inclusion of measures of CI in human studies examining impulsivity. Animal studies examining impulsivity should also include assessments of CI and these measures should be harmonized in accordance with human studies of the disorders being modeled in the preclinical investigations. The choice of specific CI measures to be included should be based on the goals of the study and existing preclinical and clinical literature using established CI measures. PMID:25867841

  13. Psychological, neuroimaging, and biochemical studies on functional association between impulsive behavior and the 5-HT2A receptor gene polymorphism in humans.

    PubMed

    Nomura, Michio; Nomura, Yasuyuki

    2006-11-01

    It has been suggested that impulsive behavior is caused by dysfunctional serotonergic 5-HT neurotransmission in the central nervous system (CNS). Brain neuroimaging studies have shown that behavioral inhibition is linked to the activation of cortex sites such as the ventral frontal cortex. Positron emission tomography (PET) imaging with [(18)F]altanserin to characterize 5-HT(2A) receptor binding revealed a reduction in 5-HT(2A) binding in the ventral frontal cortex in women who had recovered from impulsive diseases. These clinical, neuroimaging, and pharmacological studies appear to support the hypothesis that functional alteration of neurotransmission due to genetic polymorphisms of the 5-HT receptors may be involved in impulsive behavior modulation. Following evaluation by a self-reporting measure, it was proposed that a polymorphism in the promoter of the 5-HT(2A) receptor gene is the underlying cause of impulsive behavior; however, this hypothesis is not convincing. We examined whether the polymorphism in the 5-HT(2A) receptor gene promoter is involved in impulsive aggression by evaluating a behavioral task (Go/No-go task) in normal volunteers. The polymorphism of the 5-HT(2A) receptor gene promoter in lymphocytes from 71 volunteers was analyzed by using PCR. Impulsivity was defined as the number of commission errors (responding when one should not) recorded during a Go/No-go task; a larger number of commission errors indicate greater difficulty in inhibiting impulsive behavior. The subjects of the A-1438A allele group for the 5-HT(2A) receptor gene made more commission errors under the punishment-reward (PR)condition in a Go/No-go task than those in the G-1438G group. In the present review, we discuss and suggest the possible involvement of the A-1438A polymorphism of the 5HT2A receptor gene promoter in impulsive behavior. This hypothesis was evaluated by using a behavioral task measure that could directly reveal impulsive behavioral traits in humans.

  14. Bone marrow transplant – children - discharge

    MedlinePlus

    Transplant - bone marrow - children - discharge; Stem cell transplant - children - discharge; Hematopoietic stem cell transplant -children - discharge; Reduced intensity, non-myeloablative transplant - children - discharge; Mini transplant - children - discharge; Allogenic ...

  15. Imaging and spectrophotometric measurement of lightning by JEM-GLIMS

    NASA Astrophysics Data System (ADS)

    Adachi, T.; Sato, M.; Mihara, M.; Ushio, T.; Yamazaki, A.; Suzuki, M.; Kikuchi, M.; Takahashi, Y.; Inan, U.; Linscott, I.; Hobara, Y.; Hayashi, S.; Kusunoki, K.

    2014-12-01

    The purpose of the present study is to clarify the optical characteristics of lightning and to assess the effectiveness of multi-color imaging and photometric measurements in advancing our understanding of the discharge physics, meteorological aspects, and climatological properties of lightning. The instrument used here is JEM-GLIMS on board the international space station. GLIMS observes lightning and TLEs in the nadir direction with optical and radio sensors: dual-color imagers, six-color photometers, a VLF monopole antenna and a set of VHF interferometer. Since the initial operation in November 2012, GLIMS detected 1035 lightning events by imagers and photometers. The estimated peak irradiance of lightning at a wavelength range of 600-900 nm was in the range of 3.3x10-5-6.1x10-3 W/m2 with a median value of 2.4x10-3 W/m2, which is roughly equivalent to the top 10 % bright lightning events observed by FORTE in the past. The obtained photometric data showed various lightning waveforms. In some cases, one or several distinctive impulsive emissions occur and sometimes continuous emissions follow, which are suggestive of return strokes and continuing current. While in other cases, the waveform data consist of numerous intermittent optical pulses suggesting the occurrence of intra-cloud discharges. Interestingly, spectral data show the red-shift of the color of lightning at the time of possible return stroke, which could also be used as an indicator of ground discharge. Concurrent image data show complicated spatial structures which are variable from event to event in terms of pattern complexity, horizontal size, and optical intensity. These results suggest that GLIMS efficiently obtains spatiotemporal and spectral properties of lightning. In the paper, we will thoroughly examine the data obtained by the GLIMS dual-color imager and spectrophotometer.

  16. Charging of moving surfaces by corona discharges sustained in air

    SciTech Connect

    Wang, Jun-Chieh Kushner, Mark J.; Zhang, Daihua; Leoni, Napoleon Birecki, Henryk Gila, Omer

    2014-07-28

    Atmospheric pressure corona discharges are used in electrophotographic (EP) printing technologies for charging imaging surfaces such as photoconductors. A typical corona discharge consists of a wire (or wire array) biased with a few hundred volts of dc plus a few kV of ac voltage. An electric discharge is produced around the corona wire from which electrons drift towards and charge the underlying dielectric surface. The surface charging reduces the voltage drop across the gap between the corona wire and the dielectric surface, which then terminates the discharge, as in a dielectric barrier discharge. In printing applications, this underlying surface is continuously moving throughout the charging process. For example, previously charged surfaces, which had reduced the local electric field and terminated the local discharge, are translated out of the field of view and are replaced with uncharged surface. The uncharged surface produces a rebound in the electric field in the vicinity of the corona wire which in turn results in re-ignition of the discharge. The discharge, so reignited, is then asymmetric. We found that in the idealized corona charging system we investigated, a negatively dc biased corona blade with a dielectric covered ground electrode, the discharge is initially sustained by electron impact ionization from the bulk plasma and then dominated by ionization from sheath accelerated secondary electrons. Depending on the speed of the underlying surface, the periodic re-ignition of the discharge can produce an oscillatory charging pattern on the moving surface.

  17. Impulse Testing of Corporate-Fed Patch Array Antennas

    NASA Technical Reports Server (NTRS)

    Chamberlain, Neil F.

    2011-01-01

    This paper discusses a novel method for detecting faults in antenna arrays. The method, termed Impulse Testing, was developed for corporate-fed patch arrays where the element is fed by a probe and is shorted at its center. Impulse Testing was devised to supplement conventional microwave measurements in order to quickly verify antenna integrity. The technique relies on exciting each antenna element in turn with a fast pulse (or impulse) that propagates through the feed network to the output port of the antenna. The resulting impulse response is characteristic of the path through the feed network. Using an oscilloscope, a simple amplitude measurement can be made to detect faults. A circuit model of the antenna elements and feed network was constructed to assess various fault scenarios and determine fault-detection thresholds. The experimental setup and impulse measurements for two patch array antennas are presented. Advantages and limitations of the technique are discussed along with applications to other antenna array topologies

  18. Impulsive pressurization of neuronal cells for traumatic brain injury study.

    PubMed

    Nienaber, Matthew; Lee, Jeong Soon; Feng, Ruqiang; Lim, Jung Yul

    2011-10-12

    A novel impulsive cell pressurization experiment has been developed using a Kolsky bar device to investigate blast-induced traumatic brain injury (TBI). We demonstrate in this video article how blast TBI-relevant impulsive pressurization is applied to the neuronal cells in vitro. This is achieved by using well-controlled pressure pulse created by a specialized Kolsky bar device, with complete pressure history within the cell pressurization chamber recorded. Pressurized neuronal cells are inspected immediately after pressurization, or further incubated to examine the long-term effects of impulsive pressurization on neurite/axonal outgrowth, neuronal gene expression, apoptosis, etc. We observed that impulsive pressurization at about 2 MPa induces distinct neurite loss relative to unpressurized cells. Our technique provides a novel method to investigate the molecular/cellular mechanisms of blast TBI, via impulsive pressurization of brain cells at well-controlled pressure magnitude and duration.

  19. Surface micro-discharges on spacecraft dielectrics

    NASA Technical Reports Server (NTRS)

    Balmain, K. G.; Cuchanski, M.; Kremer, P. C.

    1977-01-01

    Extensive measurements on Teflon and Kapton in a scanning electron microscope indicate the existence of a well-defined family of surface micro-discharges characteristic of the dielectric material. For a given small region exposed to the 16-20 kV electron beam, the strongest discharge pulses are similar in shape and amplitude. For Teflon, typical pulse durations are 2-3 ns, rise and fall times are sometimes as low as 0.2 ns, current amplitudes are approximately 100 mA flowing down to the pedestal and the pulses are unidirectional with no ringing. The use of a rapid-scan electron microscope with a secondary-electron imaging system reveals complex charge distributions resembling Lichtenberg figures on a supposedly flat homogeneous dielectric surface. These patterns undergo extensive alteration at each micro-discharge pulse and indicate that both the charging and discharging processes are highly nonuniform over the dielectric surface. The use of floodbeam causes the occurrence of a large-scale macro-discharges, in which a typical peak current is 40 A with a duration of 120 ns.

  20. Impulsivity and self-harm in adolescence: a systematic review.

    PubMed

    Lockwood, Joanna; Daley, David; Townsend, Ellen; Sayal, Kapil

    2017-04-01

    Research supports an association between impulsivity and self-harm, yet inconsistencies in methodology across studies have complicated understanding of this relationship. This systematic review examines the association between impulsivity and self-harm in community-based adolescents aged 11-25 years and aims to integrate findings according to differing concepts and methods. Electronic searches of EMBASE, MEDLINE, PsychINFO, CINAHL, PubMed and The Cochrane Library, and manual searches of reference lists of relevant reviews identified 4496 articles published up to July 2015, of which 28 met inclusion criteria. Twenty-four of the studies reported an association between broadly specified impulsivity and self-harm. However, findings varied according to the conception and measurement of impulsivity and the precision with which self-harm behaviours were specified. Specifically, lifetime non-suicidal self-injury was most consistently associated with mood-based impulsivity-related traits. However, cognitive facets of impulsivity (relating to difficulties maintaining focus or acting without forethought) differentiated current self-harm from past self-harm. These facets also distinguished those with thoughts of self-harm (ideation) from those who acted on thoughts (enaction). The findings suggested that mood-based impulsivity is related to the initiation of self-harm, while cognitive facets of impulsivity are associated with the maintenance of self-harm. In addition, behavioural impulsivity is most relevant to self-harm under conditions of negative affect. Collectively, the findings indicate that distinct impulsivity facets confer unique risks across the life-course of self-harm. From a clinical perspective, the review suggests that interventions focusing on reducing rash reactivity to emotions or improving self-regulation and decision making may offer most benefit in supporting those who self-harm.