WorldWideScience
1

A theoretical and experimental investigation of the linear and nonlinear impulse responses from a magnetoplasma column  

Science.gov (United States)

Linear and nonlinear responses of a magnetoplasma resulting from inhomogeneity in the background plasma density are studied. The plasma response to an impulse electric field was measured and the results are compared with the theory of an inhomogeneous cold plasma. Impulse responses were recorded for the different plasma densities, static magnetic fields, and neutral pressures and generally appeared as modulated, damped oscillations. The frequency spectra of the waveforms consisted of two separated resonance peaks. For weak excitation, the results correlate with the linear theory of a cold, inhomogeneous, cylindrical magnetoplasma. The damping mechanism is identified with that of phase mixing due to inhomogeneity in plasma density. With increasing excitation voltage, the nonlinear impulse responses display stronger damping and a small increase in the frequency of oscillation.

Grody, N. C.

1973-01-01

2

Ultrahigh Specific Impulse Nuclear Thermal Propulsion  

Energy Technology Data Exchange (ETDEWEB)

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.

Anne Charmeau; Brandon Cunningham; Samim Anghaie

2009-02-09

3

Cognitive impulsivity in specific learning disabilities.  

Science.gov (United States)

Many studies on cognitive impulsivity in learning disabled children have been criticized for their methodological limitations, and they have not dealt with the different types of learning disability. The aim of this study was to overcome these limitations and to assess if there was a significant cognitive impulsivity in reading disorder and/or spelling disorder by using the 20-item Matching Familiar Figures Test (MFF20). A total of 110 children (second through eighth grades) were recruited from a cohort of children assessed for the first time in a National Health clinic specialized in the study of specific learning disabilities. In all, 30 dyslexic children and 25 children with spelling disorder (all children without an ADHD comorbidity) were compared with 55 children of a control group on the MMF20 (accuracy and time latency). Results showed that the children with reading disorder were less accurate than the children with spelling disability (p<0.05). Both these groups performed less accurately than the control group. Subjects with dyslexia were faster than both the other groups in response time (p<0.05), clearly showing a significantly higher cognitive impulsivity than the other groups. Hence, data seem to confirm the idea that, similar to ADHD children, dyslexic children have impaired frontal/prefrontal functions. Clinical and treatment implications are discussed. PMID:15981139

Donfrancesco, Renato; Mugnaini, Daniele; Dell'Uomo, Andrea

2005-08-01

4

Dimensions and disorder specificity of impulsivity in pathological gambling.  

Science.gov (United States)

Impulsivity is a core characteristic of pathological gambling (PG), even though the underlying structure and disorder specificity is unclear. This study aimed to explore different dimensions of impulsivity in a clinical sample including PG. Furthermore, we aimed to test which alterations of the impulsivity-related dimensions are disorder specific for PG. Participants were individuals diagnosed with PG (n=51) and two groups also characterized by various impulsive behaviors: an alcohol dependence (AD; n=45) and a Gilles de la Tourette syndrome (GTS; n=49) group. A healthy control (HC; n=53) group was recruited as comparison group. A comprehensive assessment was used including impulsivity-related and antipodal parameters of the Stop Signal Task, Stroop Task, Tower of London Task, Card Playing Task, Iowa Gambling Task and the Barratt Impulsiveness Scale-11. Principal axis factor analysis revealed four impulsivity-related dimensions that were labeled 'self-reported impulsivity', 'prepotent response impulsivity', 'choice impulsivity' and 'motor impulsivity'. The PG group scored significantly higher on all four dimensions compared to the HC group. In contrast, the PG group did not differ on any of the dimensions from the AD or the GTS group, except for 'choice impulsivity' where the PG group exhibited higher factor scores compared to the GTS group. Altogether, PG is associated with generally heightened impulsivity profiles compared to a HC group, which may be further used for intervention strategies. However, heightened scores in the impulsivity dimensions are not disorder specific for PG. Further research on shared or different underlying mechanisms of these overlapping impulsivity impairments is necessary. PMID:24930455

Kräplin, Anja; Bühringer, Gerhard; Oosterlaan, Jaap; van den Brink, Wim; Goschke, Thomas; Goudriaan, Anna E

2014-11-01

5

Domain-Specific Impulsivity in School-Age Children  

OpenAIRE

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 and interpersonal-related impulsivity, as observed by teachers, parents, and the students themselves, are distinct, moderately correlated behavioral t...

Tsukayama, Eli; Duckworth, Angela Lee; Kim, Betty

2013-01-01

6

Mission maps for use in the choice of specific impulse for manned Mars missions  

Energy Technology Data Exchange (ETDEWEB)

The choice of engine concept for the initial manned missions to Mars should be driven by what can be feasibly built and flight qualified in the near term, and by the level of engine performance that is required for these missions. This paper addresses how mission requirements affect the choice of specific impulse, and consequently what values of the specific impulse best serve these missions. Broad mission surveys and sensitivity studies were performed to determine the specific impulse values that allow for fast transfer times and wide launch windows. We find that a specific impulse of around 1000 to 1200 sec is sufficient. Choosing an engine concept that has a higher specific impulse value is not justified for these missions because the modest reduction in propellant requirements and further widening of the launch windows does not compensate for the substantially greater technical risk. 3 refs., 8 figs.

Madsen, W.W.; Neuman, J.E.; Olson, T.S.; Siahpush, A.S.

1991-01-01

7

Liquid Engine Design: Effect of Chamber Dimensions on Specific Impulse  

Science.gov (United States)

Which assumption of combustion chemistry - frozen or equilibrium - should be used in the prediction of liquid rocket engine performance calculations? Can a correlation be developed for this? A literature search using the LaSSe tool, an online repository of old rocket data and reports, was completed. Test results of NTO/Aerozine-50 and Lox/LH2 subscale and full-scale injector and combustion chamber test results were found and studied for this task. NASA code, Chemical Equilibrium with Applications (CEA) was used to predict engine performance using both chemistry assumptions, defined here. Frozen- composition remains frozen during expansion through the nozzle. Equilibrium- instantaneous chemical equilibrium during nozzle expansion. Chamber parameters were varied to understand what dimensions drive chamber C* and Isp. Contraction Ratio is the ratio of the nozzle throat area to the area of the chamber. L is the length of the chamber. Characteristic chamber length, L*, is the length that the chamber would be if it were a straight tube and had no converging nozzle. Goal: Develop a qualitative and quantitative correlation for performance parameters - Specific Impulse (Isp) and Characteristic Velocity (C*) - as a function of one or more chamber dimensions - Contraction Ratio (CR), Chamber Length (L ) and/or Characteristic Chamber Length (L*). Determine if chamber dimensions can be correlated to frozen or equilibrium chemistry.

Hoggard, Lindsay; Leahy, Joe

2009-01-01

8

Dynamics of specific heat and other relaxation processes in supercooled liquids by impulsive stimulated scattering  

Energy Technology Data Exchange (ETDEWEB)

Laser based impulsive stimulated scattering or transient grating excitation in a heterodyne diffraction scheme is a powerful method to extract information about different relaxing properties from different signal contributions. Longitudinal acoustic waves are detected simultaneously with thermal expansion and thermal diffusion. Careful fitting of the time-domain density response at different temperatures makes it possible to obtain the various relaxing physical parameters, and to construct Arrhenius plots for the respective relaxation processes. In this work we focus on the influence of the specific heat capacity C on the slower part of the density response function S{sub {rho}}(t), and, inversely, on the possibility to extract from experimental S{sub {rho}}(t) data the relaxation behaviour C({omega}). The specific heat capacity is relevant for both the initially rising part of the impulsive stimulated scattering signal (together with the time and frequency dependent thermal expansion {gamma}(t)), and for the thermal diffusion dominated decrease of the signal at later times after the excitation. By simulating S{sub {rho}}(t) data in different scenarios, we address the feasibility of unravelling the impulse response functions C(t) and {gamma}(t) (and via Fourier transform also C({omega}) and {gamma}({omega})) by careful fitting of the signal. This approach offers a unique possibility to extend the 100 kHz bandwidth of current dynamic calorimetric techniques determining C({omega}) (photopyroelectric spectroscopy) to the sub-GHz range.

Fivez, J [HUB, Stormstraat 2, B-1000 Brussel (Belgium); Salenbien, R; Malayil, M Kuriakose; Schols, W; Glorieux, C, E-mail: christ.glorieux@fys.kuleuven.b [Laboratorium voor Akoestiek en Thermische Fysica, Department Natuurkunde en Sterrenkunde, Katholieke Universiteit Leuven, Celestijnenlaan 200 D, B- 3001 Leuven (Belgium)

2011-01-01

9

Single stage to orbit mass budgets derived from propellant density and specific impulse  

Energy Technology Data Exchange (ETDEWEB)

The trade between specific impulse (Isp) and density is examined in view of Single Stage To Orbit (SSTO) requirements. Mass allocations for vehicle hardware are derived from these two properties, for several propellant combinations and a dual-fuel case. This comparative analysis, based on flight-proven hardware, indicates that the higher density of several alternative propellants compensates for reduced Isp, when compared with cryogenic oxygen and hydrogen. Approximately half the orbiting mass of a rocket- propelled SSTO vehicle must be allocated to propulsion hardware and residuals. Using hydrogen as the only fuel requires a slightly greater fraction of orbiting mass for propulsion, because hydrogen engines and tanks are heavier than those for denser fuels. The advantage of burning both a dense fuel and hydrogen in succession depends strongly on tripropellant engine weight. The implications of the calculations for SSTO vehicle design are discussed, especially with regard to the necessity to minimize non-tankage structure.

Whitehead, J.C.

1996-06-06

10

Liquid-fueled, Laser-powered, N-class thrust Space Engine with Variable Specific Impulse  

International Nuclear Information System (INIS)

We discuss the requirements for developing a lightweight laser-powered space engine with specific impulse range 200spsp. We have shown that Isp = 680 seconds can be achieved by a viscous fuel based on glycidyl azide polymer and an IR-dye laser absorber. The second problem is optics clouding from ablated material. This can be handled actively by a flowing gas system. The final problem is mass: we will present an engine design which fits within a 10-kg 'dry mass' budget.The engine, 80 kg mass with fuel, is designed to fit within a 180-kg spacecraft, aned to fit within a 180-kg spacecraft, and use up 3 kW of prime power to deliver a ?v of 17.5 km/s to the spacecraft in sixteen months

11

Irreversible processes in a magnetoplasma  

International Nuclear Information System (INIS)

Magnetically confined plasmas exhibit some interesting instabilities that have somewhat bedeviled the long quest for fusion power in tokamak machines. The magnetic fields employed are strong in the sense that the parameter anti ? triple bond ?c?, where ?c is the cyclotron frequency and ? is the collision interval, is a very large number. The purpose of the paper is to relate these instabilities to ?, the entropy production rate per unit volume. In a neutral gas ? is non-negative, which result can be obtained as a local form of Boltzmann's H-theorem. With ? expanded in the Knudsen number (?) power series, ? = ?1 + ?2 + ..., where ?1 is the familiar, non-negative quadratic form, the second-order term ?2 = O(?2), may have either sign. In the usual case, for ? small enough, ?1 >>vertical stroke ?2vertical stroke and the inequality ? ? 0 follows. However in a magnetoplasma, we shall show that ?1 = O(anti ?-2), whereas ?2 = O(anti ?-1). This means that in tokamaks ?2 (which may have either sign) dominates ?1. It is therefore possible that in some circumstances ? is negative and the outcome is an unstable fluctuation. Another way of expressing this result, is that the heat flows up the temperature gradient, albeit only for a short time. In the course of establishing this surshing this surprising result, we shall give a method of calculating ?2 that is independent of the form of Boltzmann's collision integral. Our conclusions are supported by reference to tokamak experiments. (orig.)

12

Alfvenic shock waves in a collisional magnetoplasma  

International Nuclear Information System (INIS)

Compressional Alfvenic shock waves in a cold collisional magnetoplasma are investigated. For this purpose, we use the hydrodynamic equations and Faraday's law to derive the governing nonlinear equations for the compressional Alfven waves. It is shown that the latter can appear in the form of Alfvenic shock waves. -- Highlights: ? We model Alfvenic shock waves in a cold collisional plasma. ? The shock waves appear as monotonic or oscillatory, depending on temporal and spatial scales. ? Can be responsible for cross-field proton acceleration.

13

TM Waves Propagation at Magnetoplasma-MTMs Interface  

Directory of Open Access Journals (Sweden)

Full Text Available A new structure for isolator is proposed in this work. The proposed structure consists of metamaterial-magnetoplasma semiconductors parallel plate structure. The utility of magnetoplasma semiconductors is promising in developing nonreciprocal components in the submillimeter-wave and millimeter-wave bands for satellite communications. Metamaterials (MTMs is used to enhance the behavior of the isolator.

Rifa J. El-Khozondar

2012-11-01

14

Jeans stability in collisional quantum dusty magnetoplasmas  

International Nuclear Information System (INIS)

Jeans instability is examined in detail in uniform dusty magnetoplasmas taking care of collisional and non-zero finite thermal effects in addition to the quantum characteristics arising through the Bohm potential and the Fermi degenerate pressure using the quantum hydrodynamic model of plasmas. It is found that the presence of the dust-lower-hybrid wave, collisional effects of plasma species, thermal effects of electrons, and the quantum mechanical effects of electrons have significance over the Jeans instability. Here, we have pointed out a new class of dissipative instability in quantum plasma regime

15

Jeans stability in collisional quantum dusty magnetoplasmas  

Science.gov (United States)

Jeans instability is examined in detail in uniform dusty magnetoplasmas taking care of collisional and non-zero finite thermal effects in addition to the quantum characteristics arising through the Bohm potential and the Fermi degenerate pressure using the quantum hydrodynamic model of plasmas. It is found that the presence of the dust-lower-hybrid wave, collisional effects of plasma species, thermal effects of electrons, and the quantum mechanical effects of electrons have significance over the Jeans instability. Here, we have pointed out a new class of dissipative instability in quantum plasma regime.

Jamil, M.; Mir, Zahid; Asif, M.; Salimullah, M.

2014-09-01

16

Alfvenic shock waves in a collisional magnetoplasma  

Energy Technology Data Exchange (ETDEWEB)

Compressional Alfvenic shock waves in a cold collisional magnetoplasma are investigated. For this purpose, we use the hydrodynamic equations and Faraday's law to derive the governing nonlinear equations for the compressional Alfven waves. It is shown that the latter can appear in the form of Alfvenic shock waves. -- Highlights: ? We model Alfvenic shock waves in a cold collisional plasma. ? The shock waves appear as monotonic or oscillatory, depending on temporal and spatial scales. ? Can be responsible for cross-field proton acceleration.

Shukla, P.K., E-mail: profshukla@yahoo.de [International Centre for Advanced Studies in Physical Sciences, Faculty of Physics and Astronomy, Ruhr University Bochum, D-44780 Bochum (Germany); Eliasson, B., E-mail: beliass@yahoo.se [International Centre for Advanced Studies in Physical Sciences, Faculty of Physics and Astronomy, Ruhr University Bochum, D-44780 Bochum (Germany); Stenflo, L., E-mail: lennart.stenflo@physics.umu.se [Department of Physics, Linkoeping University, SE-58183 Linkoeping (Sweden)

2011-06-13

17

Relativistic kinetic theory of magnetoplasmas  

OpenAIRE

Recently, an increasing interest in astrophysical as well as laboratory plasmas has been manifested in reference to the existence of relativistic flows, related in turn to the production of intense electric fields in magnetized systems. Such phenomena require their description in the framework of a consistent relativistic kinetic theory, rather than on relativistic MHD equations, subject to specific closure conditions. The purpose of this work is to apply the relativistic si...

Beklemishev, Alexei; Nicolini, Piero; Tessarotto, Massimo

2004-01-01

18

Generalised impulse approximation  

International Nuclear Information System (INIS)

A generalisation of the impulse approximation for heavy-particle collisions is developed in the formalism of two-channel distortion. Both rearrangement and direct processes are studied with this approximation. A large variety of approaches (including the impulse approximation, the continuum distorted wave, the Born approximation, etc) can be obtained from it by specific steps. (author)

19

Sex differences in impulsive action and impulsive choice.  

Science.gov (United States)

Here, we review the evidence for sex differences in behavioral measures of impulsivity for both humans and laboratory animals. We focus on two specific components of impulsivity: impulsive action (i.e., difficulty inhibiting a prepotent response) and impulsive choice (i.e., difficulty delaying gratification). Sex differences appear to exist on these measures, but the direction and magnitude of the differences vary. In laboratory animals, impulsive action is typically greater in males than females, whereas impulsive choice is typically greater in females. In humans, women discount more steeply than men, but sex differences on measures of impulsive action depend on tasks and subject samples. We discuss implications of these findings as they relate to drug addiction. We also point out the major gaps in this research to date, including the lack of studies designed specifically to examine sex differences in behavioral impulsivity, and the lack of consideration of menstrual or estrous phase or sex hormone levels in the studies. PMID:24286704

Weafer, Jessica; de Wit, Harriet

2014-11-01

20

Rayleigh-Taylor/gravitational instability in dense magnetoplasmas  

International Nuclear Information System (INIS)

The Rayleigh-Taylor instability is investigated in a nonuniform dense quantum magnetoplasma. For this purpose, a quantum hydrodynamical model is used for the electrons whereas the ions are assumed to be cold and classical. The dispersion relation for the Rayleigh-Taylor instability becomes modified with the quantum corrections associated with the Fermi pressure law and the quantum Bohm potential force. Numerically, it is found that the quantum speed and density gradient significantly modify the growth rate of RT instability. In a dense quantum magnetoplasma case, the linear growth rate of RT instability becomes significantly higher than its classical value and the modes are found to be highly localized. The present investigation should be useful in the studies of dense astrophysical magnetoplasmas as well as in laser-produced plasmas.

21

Rayleigh-Taylor/gravitational instability in dense magnetoplasmas  

Energy Technology Data Exchange (ETDEWEB)

The Rayleigh-Taylor instability is investigated in a nonuniform dense quantum magnetoplasma. For this purpose, a quantum hydrodynamical model is used for the electrons whereas the ions are assumed to be cold and classical. The dispersion relation for the Rayleigh-Taylor instability becomes modified with the quantum corrections associated with the Fermi pressure law and the quantum Bohm potential force. Numerically, it is found that the quantum speed and density gradient significantly modify the growth rate of RT instability. In a dense quantum magnetoplasma case, the linear growth rate of RT instability becomes significantly higher than its classical value and the modes are found to be highly localized. The present investigation should be useful in the studies of dense astrophysical magnetoplasmas as well as in laser-produced plasmas.

Ali, S., E-mail: shahid.ali@ncp.edu.p [National Centre for Physics, Quaid-i-Azam University Campus, Islamabad (Pakistan); IPFN, Instituto Superior Tecnico, Av. Rovisco Pais, 1049-001 Lisboa (Portugal); Ahmed, Z. [COMSATS Institute of Information Technology, Department of Physics, Wah Campus (Pakistan); Mirza, Arshad M. [Theoretical Plasma Physics Group, Physics Department, Quaid-i-Azam University, Islamabad 45320 (Pakistan); Ahmad, I. [COMSATS Institute of Information Technology, Department of Physics, Islamabad Campus (Pakistan)

2009-08-10

22

Magneto-Plasma Processes in Relativistic Astrophysics: Modern Developments  

Science.gov (United States)

This contribution is a review of some talks presented at the session `Magneto-Plasma Processes in Relativistic Astrophysics' of the Thirteenth Marcel Grossmann Meeting MG13. We discuss the modern developments of relativistic astrophysics, connected with presence of plasma and magnetic fields. The influence of magneto-plasma processes on the structure of the compact objects and accretion processes is considered. We also discuss a crucial role of magnetic field for the mechanism of core-collapse supernova explosions. Gravitational lensing in plasma is also considered.

Tsupko, Oleg Yu.

2015-01-01

23

Generalized Covariant Gyrokinetic Dynamics of Magnetoplasmas  

International Nuclear Information System (INIS)

A basic prerequisite for the investigation of relativistic astrophysical magnetoplasmas, occurring typically in the vicinity of massive stellar objects (black holes, neutron stars, active galactic nuclei, etc.), is the accurate description of single-particle covariant dynamics, based on gyrokinetic theory (Beklemishev et al., 1999-2005). Provided radiation-reaction effects are negligible, this is usually based on the assumption that both the space-time metric and the EM fields (in particular the magnetic field) are suitably prescribed and are considered independent of single-particle dynamics, while allowing for the possible presence of gravitational/EM perturbations driven by plasma collective interactions which may naturally arise in such systems. The purpose of this work is the formulation of a generalized gyrokinetic theory based on the synchronous variational principle recently pointed out (Tessarotto et al., 2007) which permits to satisfy exactly the physical realizability condition for the four-velocity. The theory here developed includes the treatment of nonlinear perturbations (gravitational and/or EM) characterized locally, i.e., in the rest frame of a test particle, by short wavelength and high frequency. Basic feature of the approach is to ensure the validity of the theory both for large and vanishing parallel electric field. It is shown that the correct treatment of EM perturbations occurring in the presence of an intense background magnetic field general intense background magnetic field generally implies the appearance of appropriate four-velocity corrections, which are essential for the description of single-particle gyrokinetic dynamics.

24

Impulse Response Function  

OpenAIRE

Impulse response functions are useful for studying the interactions between variables in a vector autoregressive model. They represent the reactions of the variables to shocks hitting the system. It is often not clear, however, which shocks are relevant for studying specific economic problems. Therefore structural information has to be used to specify meaningful shocks. Structural vector autoregressive models and the estimation of impulse responses are discussed and extensions to models with ...

Luetkepohl, Helmut

2008-01-01

25

The Influence of Current Density and Magnetic Field Topography in Optimizing the Performance, Divergence, and Plasma Oscillations of High Specific Impulse Hall Thrusters  

Science.gov (United States)

Recent studies of xenon Hall thrusters have shown peak efficiencies at specific impulses of less than 3000 s. This was a consequence of modern Hall thruster magnetic field topographies, which have been optimized for 300 V discharges. On-going research at the NASA Glenn Research Center is investigating this behavior and methods to enhance thruster performance. To conduct these studies, a laboratory model Hall thruster that uses a pair of trim coils to tailor the magnetic field topography for high specific impulse operation has been developed. The thruster-the NASA-173Mv2 was tested to determine how current density and magnetic field topography affect performance, divergence, and plasma oscillations at voltages up to 1000 V. Test results showed there was a minimum current density and optimum magnetic field topography at which efficiency monotonically increased with voltage. At 1000 V, 10 milligrams per second the total specific impulse was 3390 s and the total efficiency was 60.8%. Plume divergence decreased at 400-1000 V, but increased at 300-400 V as the result of plasma oscillations. The dominant oscillation frequency steadily increased with voltage, from 14.5 kHz at 300 V, to 22 kHz at 1000 V. An additional oscillatory mode in the 80-90 kHz frequency range began to appear above 500 V. The use of trim coils to modify the magnetic field improved performance while decreasing plume divergence and the frequency and magnitude of plasma oscillations.

Hofer, Richard R.; Jankovsky, Robert S.

2003-01-01

26

Specific dimensions of impulsivity are differentially associated with daily and non-daily cigarette smoking in young adults.  

Science.gov (United States)

Young adults are at risk for initiation of tobacco use and progression to tobacco dependence. Not every person who smokes cigarettes becomes tobacco dependent, however, and non-daily smoking is becoming more prevalent among those who use tobacco. It is likely that individual differences in psychosocial and behavioral factors influence risk for engaging in non-daily and daily cigarette smoking. The objective of this study was to investigate the associations between impulsivity and smoking status in young adults who vary in frequency of cigarette smoking. Young adult first-year college students between the ages of 18-24 (512) were classified to one of three groups: non-smokers, non-daily smokers, or daily smokers, and impulsivity was assessed using the UPPS-P (negative and positive urgency, lack of premeditation, lack of perseverance, sensation seeking). When all impulsivity dimensions were used simultaneously to predict smoking status, negative urgency predicted increased risk of membership in the daily smoking group and lack of premeditation predicted increased risk of membership in the non-daily smoking group. These results suggest that dimensions of impulsivity may contribute differentially to forms of smoking behavior in young adults. PMID:25827335

Lee, Dustin C; Peters, Jessica R; Adams, Zachary W; Milich, Richard; Lynam, Donald R

2015-07-01

27

Excoriation disorder: Impulsivity and its clinical associations.  

Science.gov (United States)

Excoriation disorder is the repetitive scratching or picking of skin that leads to physical damage, distress, and functional impairment. Skin picking has been associated with impulsivity and problems with inhibition. We hypothesized that problems in these areas could be disease severity markers. We recruited 73 adults meeting DSM-5 criteria for excoriation disorder, and 50 adult controls. Those with excoriation disorder were categorized as either "high impulsive" (HI) or "low impulsive" (LI) using either a neurocognitive task of motor impulsivity (Stop Signal Task) or the Barratt Impulsiveness Scale's (BIS-11) motor impulsivity subscale. The HI subjects, based on the BIS-11, showed higher urges scores, anxiety, and depressive symptoms. These data suggest that impulsivity may reflect a specific clinical presentation among those with excoriation disorder, but the clinical characteristics differ depending upon the impulsivity measure used. Agreement on how to measure various domains of impulsivity may be important in better understanding the disorder psychopathology and so improve future treatments. PMID:25591046

Oliveira, Elen C B; Leppink, Eric W; Derbyshire, Katherine L; Grant, Jon E

2015-03-01

28

Impulse arrays  

Science.gov (United States)

This report considers impulse radar signals in terms of their propagation from an array of elements. The far-field electric vector is proportional to the derivative of the current in an infinitesimal dipole representing each element. Although not physically realizable, this model is used as an approximation to illustrate some array properties peculiar to impulse, or ultra-wideband (UWB), excitations. Thus, for example, a 1-ns rounded baseband pulse with a cosine-squared shape theoretically propagates as a single sinusoidal cycle centered at L-band (1 GHz) with 100 percent bandwidth. The far field from an array of elements is considered as a function of angle.

Temes, C. L.

1991-05-01

29

Tridimensional Personality Questionnaire data on alcoholic violent offenders: specific connections to severe impulsive cluster B personality disorders and violent criminality  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background The validity of traditional categorical personality disorder diagnoses is currently re-evaluated from a continuous perspective, and the evolving DSM-V classification may describe personality disorders dimensionally. The utility of dimensional personality assessment, however, is unclear in violent offenders with severe personality pathology. Methods The temperament structure of 114 alcoholic violent offenders with antisocial personality disorder (ASPD was compared to 84 offenders without ASPD, and 170 healthy controls. Inclusion occurred during a court-ordered mental examination preceded by homicide, assault, battery, rape or arson. Participants underwent assessment of temperament with the Tridimensional Personality Questionnaire (TPQ and were diagnosed with DSM-III-R criteria. Results The typical temperament profile in violent offender having ASPD comprised high novelty seeking, high harm avoidance, and low reward dependence. A 21% minority scored low in trait harm avoidance. Results, including the polarized harm avoidance dimension, are in accordance with Cloninger's hypothesis of dimensional description of ASPD. The low harm avoidance offenders committed less impulsive violence than high harm avoidance offenders. High harm avoidance was associated with comorbid antisocial personality disorder and borderline personality disorder. Conclusion Results indicate that the DSM based ASPD diagnosis in alcoholic violent offenders associates with impulsiveness and high novelty seeking but comprises two different types of ASPD associated with distinct second-order traits that possibly explain differences in type of violent criminality. Low harm avoidance offenders have many traits in common with high scorers on the Hare Psychopathy Checklist-Revised (PCL-R. Results link high harm avoidance with broad personality pathology and argue for the usefulness of self-report questionnaires in clinical praxis.

Lindberg Nina

2007-07-01

30

The cyclotron maser instability - Application to low-density magnetoplasmas  

International Nuclear Information System (INIS)

The cylcotron maser instability is applied to low-density magnetoplasmas to derive simple expressions relating the wave-emergent angle of the amplified wave (theta) and the ratio f/f(c) at the source to the normalized (to the light velocity c) parallel bulk velocity (PBV) of the instability (characteristic for an auroral electron distribution function). It is shown that, for PBV corresponding to 1-10 keV, theta is nearly perpendicular with respect to the magnetic field and is decreasing as PBV increases. The results are highly relevant to the lower-frequency auroral emission of Jupiter and Saturn. 21 refs

31

The cyclotron maser instability - Application to low-density magnetoplasmas  

Science.gov (United States)

The cylcotron maser instability is applied to low-density magnetoplasmas to derive simple expressions relating the wave-emergent angle of the amplified wave (theta) and the ratio f/f(c) at the source to the normalized (to the light velocity c) parallel bulk velocity (PBV) of the instability (characteristic for an auroral electron distribution function). It is shown that, for PBV corresponding to 1-10 keV, theta is nearly perpendicular with respect to the magnetic field and is decreasing as PBV increases. The results are highly relevant to the lower-frequency auroral emission of Jupiter and Saturn.

Ladreiter, H. P.

1991-03-01

32

Discharge characteristics and dynamics of compressive plasma streams generated by a compact magnetoplasma compressor  

International Nuclear Information System (INIS)

Results from experimental studies of a compact magnetoplasma compressor designed for operation with heavy gases are presented. The integral characteristics of the discharge and the energy contents and other parameters of the generated xenon plasma streams are determined.

33

Microwave magnetoplasma resonances of two-dimensional electrons in MgZnO/ZnO heterojunctions  

Science.gov (United States)

The plasma, magnetoplasma, and edge magnetoplasma excitations were investigated in two-dimensional electron systems hosted at the heterointerface of MgZnO/ZnO structures using optical detection of resonant microwave absorption. The magnetodispersion of the plasma excitations allowed the extraction of the electron effective mass. It was found to exhibit a surprisingly large dependence on the electron density, which is difficult to account for just from nonparabolicity effects.

Kozlov, V. E.; Van'kov, A. B.; Gubarev, S. I.; Kukushkin, I. V.; Solovyev, V. V.; Falson, J.; Maryenko, D.; Kozuka, Y.; Tsukazaki, A.; Kawasaki, M.; Smet, J. H.

2015-02-01

34

Compression zone formation in magnetoplasma compressor operating with heavy gases  

International Nuclear Information System (INIS)

Present work is devoted to experimental investigations of the plasma compression zone dynamics and its influence on radiation characteristics. The construction of magneto-plasma compressor (MPC) of compact geometry with conical copper electrodes is described. Comprehensive information about dynamics of compression zone formation, it position, plasma parameters and geometric dimensions was obtained using spectral diagnostics. Plasma stream density ? 1018cm-3 was measured by Stark broadening of Xe spectral lines. Electron temperature 5...7 eV was estimated using the ratio of Xe lines intensities. EUV radiation intensity was detected by registration system consisting on absolutely calibrated AXUV diodes with integrated thin-films filter for different wavelength ranges and multi-layered MoSi mirrors. Spatial distributions of electrical currents has been performed also.

35

Inductively coupled TI-MPD spacecraft electric propulsion. [thermionic magnetoplasma dynamic thruster design  

Science.gov (United States)

A nuclear electric propulsion concept using a thermionic reactor inductively coupled to a magnetoplasma-dynamic (MPD) accelerator is described and the results of preliminary analyses are presented. In this system, the thermionic generating unit operates continuously at a power level of approximately 0.4 MW, while the MPD thruster operates intermittently at higher voltages and power levels. Energy storage is provided by building up a large current in an inductor. Periodically, the charging current is interrupted and the energy stored in the magnetic field of the inductor is utilized for a short duration thrust pulse. A typical thrust pulse is characterized by a power level of 1 to 4 MWe, a duration of 1 msec, and a duty cycle of approximately 20%. Results of the preliminary analysis show that approximately 85 to 90% of the power available from the thermionic converter array can be delivered to the MPD thruster for a nominal 400 kWe system with an inductive unit suitable for a flight vehicle. Optimized values of the total specific mass of the system including the thermionic reactor, the inductor, and the MPD thruster are estimated in the range of 23 to 24 kg/kWe.

Britt, E. J.; Clark, K. E.; Pawlik, E. V.

1976-01-01

36

Soft neurological signs and impulsivity in children.  

Science.gov (United States)

To evaluate the relationship between soft neurological signs and various proposed dimensions of impulsivity (behavioral and cognitive), 31 boys (6-13 years, mean +/- SD 10.1 +/- 1.8) with disruptive behavior disorders, and 45 age-matched boys without DSM-III-R pathology, were independently assessed on clinical ratings of impulsivity, a battery of cognitive tests intended to score impulsive responding, and a neurological examination for soft signs. After being corrected for age, neurological soft signs correlated positively with impulsive responding on the Matching Familiar Figures Test (inpatients and normals) and the Continuous Performance Test (in normals), but not with IQ or clinical impulsivity rating scores. These findings suggest a relationship between neurological dysfunction/immaturity and performance on specific tasks requiring response inhibition, thus adding value to the cognitive assessment of impulsivity. PMID:2365831

Vitiello, B; Stoff, D; Atkins, M; Mahoney, A

1990-06-01

37

Anatomy of a SAR impulse response.  

Energy Technology Data Exchange (ETDEWEB)

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.

Doerry, Armin Walter

2007-08-01

38

Generation of zonal magnetic fields by drift waves in a current carrying nonuniform magnetoplasma  

International Nuclear Information System (INIS)

It is shown that zonal magnetic fields (ZMFs) can be nonlinearly excited by incoherent drift waves (DWs) in a current carrying nonuniform magnetoplasma. The dynamics of incoherent DWs in the presence of ZMFs is governed by a wave-kinetic equation. The governing equation for ZMFs in the presence of nonlinear advection force of the DWs is obtained from the parallel component of the electron momentum equation and the Faraday law. Standard techniques are used to derive a nonlinear dispersion relation, which depicts instability via which ZMFs are excited in plasmas. ZMFs may inhibit the turbulent cross-field particle and energy transport in a nonuniform magnetoplasma.

39

Theory of electromagnetic cyclotron wave growth in a time-varying magnetoplasma  

Science.gov (United States)

The effect of a time-dependent perturbation in the magnetoplasma on the wave and particle populations is investigated using the Kennel-Petchek (1966) approach. Perturbations in the cold plasma density, energetic particle distribution, and resonance condition are calculated on the basis of the ideal MHD assumption given an arbitrary compressional magnetic field perturbation. An equation is derived describing the time-dependent growth rate for parallel propagating electromagnetic cyclotron waves in a time-varying magnetoplasma with perturbations superimposed on an equilibrium configuration.

Gail, William B.

1990-01-01

40

Dissipative drift wave instability in a radially bounded nonuniform dusty magnetoplasma  

International Nuclear Information System (INIS)

Properties of the dissipative drift wave instability in a radially bounded nonuniform dusty magnetoplasma are investigated. By using the two-fluid model for the electrons and ions, we derive a nonlocal wave equation for the low-frequency collisional drift wave in the bounded system. The charged dust is assumed to be immobile on the time scale of the instability. The wave equation admits a dispersion relation, which exhibits the modification of the drift wave frequency and the dissipative drift wave instability growth rate due to radial boundaries. Possible application of our investigation to forthcoming nonuniform dusty magnetoplasma experiments is discussed.

41

Laser pulse propagation in inhomogeneous magnetoplasma channels and wakefield acceleration  

International Nuclear Information System (INIS)

Wakefield excitation in a preformed inhomogeneous parabolic plasma channel by an intense relativistic (?1019?W/cm2) circularly polarized Gaussian laser pulse is investigated analytically and numerically in the presence of an external longitudinal magnetic field. A three dimensional envelope equation for the evolution of the laser pulse is derived, which includes the effect of the nonparaxial and applied external magnetic field. A relation for the channel radius with the laser spot size is derived and examines numerically to see the external magnetic field effect. It is observed that the channel radius depends on the applied external magnetic field. An analytical expression for the wakefield is derived and validated with the help of a two dimensional particle in cell (2D PIC) simulation code. It is shown that the electromagnetic nature of the wakes in an inhomogeneous plasma channel makes their excitation nonlocal, which results in change of fields with time and external magnetic field due to phase mixing of the plasma oscillations with spatially varying frequencies. The magnetic field effect on perturbation of the plasma density and decreasing length is also analyzed numerically. In addition, it has been shown that the electron energy gain in the inhomogeneous parabolic magnetoplasma channel can be increased significantly compared with the homogeneous plasma channel

42

Laser pulse propagation in inhomogeneous magnetoplasma channels and wakefield acceleration  

Energy Technology Data Exchange (ETDEWEB)

Wakefield excitation in a preformed inhomogeneous parabolic plasma channel by an intense relativistic (?10{sup 19}?W/cm{sup 2}) circularly polarized Gaussian laser pulse is investigated analytically and numerically in the presence of an external longitudinal magnetic field. A three dimensional envelope equation for the evolution of the laser pulse is derived, which includes the effect of the nonparaxial and applied external magnetic field. A relation for the channel radius with the laser spot size is derived and examines numerically to see the external magnetic field effect. It is observed that the channel radius depends on the applied external magnetic field. An analytical expression for the wakefield is derived and validated with the help of a two dimensional particle in cell (2D PIC) simulation code. It is shown that the electromagnetic nature of the wakes in an inhomogeneous plasma channel makes their excitation nonlocal, which results in change of fields with time and external magnetic field due to phase mixing of the plasma oscillations with spatially varying frequencies. The magnetic field effect on perturbation of the plasma density and decreasing length is also analyzed numerically. In addition, it has been shown that the electron energy gain in the inhomogeneous parabolic magnetoplasma channel can be increased significantly compared with the homogeneous plasma channel.

Sharma, B. S., E-mail: bs-phy@yahoo.com; Jain, Archana [Government College Kota, Kota 324001 (India); Jaiman, N. K. [Department of Pure and Applied Physics, University of Kota, Kota 324010 (India); Gupta, D. N. [Department of Physics and Astrophysics, University of Delhi, Delhi 110007 (India); Jang, D. G.; Suk, H. [Department of Physics and Photon Science, Gwangju Institute of Science and Technology, Gwangju 500-712 (Korea, Republic of); Kulagin, V. V. [Sternberg Astronomical Institute of Moscow State University, Moscow 119992 (Russian Federation)

2014-02-15

43

Optimization of plasma flow parameters of the magnetoplasma compressor  

International Nuclear Information System (INIS)

Optimization of the working conditions of the magnetoplasma compressor (MPC) has been performed through analysing discharge and compression plasma flow parameters in hydrogen, nitrogen and argon at different pressures. Energy conversion rate, volt-ampere curve exponent and plasma flow velocities have been studied to optimize the efficiency of energy transfer from the supply source to the plasma. It has been found that the most effective energy transfer from the supply to the plasma is in hydrogen as a working gas at 1000 Pa pressure. It was found that the accelerating regime exists for hydrogen up to 3000 Pa pressures, in nitrogen up to 2000 Pa and in argon up to 1000 Pa pressure. At higher pressures MPC in all the gases works in the decelerating regime. At pressures lower than 200 Pa, high cathode erosion is observed. MPC plasma flow parameter optimization is very important because this plasma accelerating system may be of special interest for solid surface modification and other technology applications

44

Nonlinear generation of zonal flows by ion-acoustic waves in a uniform magnetoplasma  

International Nuclear Information System (INIS)

It is shown that large-scale zonal flows (ZFs) can be excited by Reynolds stress of nonlinearly interacting random phase ion-acoustic waves (EIAWs) in a uniform magnetoplasma. Since ZFs are associated with poloidal sheared flows, they can tear apart short scale EIAW turbulence eddies, and hence contribute to the reduction of the cross-field turbulent transport in a magnetized plasma.

45

Distribution of the field of electromagnetic waves in two radiation cones in a uniform magnetoplasma  

International Nuclear Information System (INIS)

The paper examines radiation from a point electric dipole in a homogeneous multicomponent magnetoplasma in the entire range of frequencies omega, which are smaller than Langmuir electron frequencies omega sub zero. Results of numerical computations in the whistler range are presented

46

Nucleus accumbens and impulsivity.  

Science.gov (United States)

The multifaceted concept of impulsivity implies that different impulsivity aspects, mediated by different neural processes, influence behavior at different levels. The nucleus accumbens (NAc) is a key component of the neural processes regulating impulsivity. In this review, we discuss the findings of lesion studies in animals and functional imaging studies in humans focusing on the role of the NAc in impulsivity. Evidence supports that the extent and pattern of involvement of the NAc, and its subregions, the core and the shell, vary among different facets of impulsivity. Data from imaging studies reviewed in this article suggest the involvement of the ventral striatum/NAc in impulsive choice. Findings of animal studies indicate that lesions of the NAc core subregion facilitated impulsivity in tasks involving intertemporal choice, and promoted a risk-averse, less impulsive, tendency in tasks involving options with probability differences. Modification of neurotransmitter activity, especially of dopamine, which is proposed to underlie the changes observed in functional imaging studies, has been shown to influence afferent input pattern in the NAc and the generation of the behavioral output. Parameters of behavioral tasks reflecting response inhibition function are altered by neurochemical interventions and local electrical stimulation in both the core and the shell subregions. In toto, NAc's pattern of neuronal activity, either genetically determined or acquired, has a critical impact on the interindividual variation in the expression of impulsivity. Nevertheless, the NAc is not the only substrate responsible for impulsivity and it is not involved in each facet of impulsivity to the same extent. PMID:20831892

Basar, Koray; Sesia, Thibaut; Groenewegen, Henk; Steinbusch, Harry W M; Visser-Vandewalle, Veerle; Temel, Yasin

2010-12-01

47

Dependence of the specific features of two PAPVD methods: Impulse Plasma Deposition (IPD) and Pulsed Magnetron Sputtering (PMS) on the structure of Fe–Cu alloy layers  

International Nuclear Information System (INIS)

This paper describes the study of the structural properties of the alloy layers prepared by two different, impulsively working PAPVD methods: the Pulsed Magnetron Sputtering (PMS) and the Impulse Plasma Deposition (IPD). The Fe–Cu alloy layers were synthesized. The results of our investigation revealed a nanocrystalline structure of the layers. The differences in the phase composition of the Fe–Cu alloy layers produced by these two methods were observed. The synthesis of the Fe–Cu layers by using the Pulsed Magnetron Sputtering method resulted in obtaining the two-phase, polycrystalline structures (fcc-Cu and bcc-Fe). In this case the clear evidence of mixing between the iron and copper atoms was not observed. The Fe–Cu layers deposited by the Impulse Plasma Deposition method were characterized by the non-equilibrium phase composition – the presence of one-phase supersaturated solid solution (fcc-Cu(Fe) or bcc-Fe(Cu)) was formed in immiscible systems. These results suggest a short-distance diffusion between the neighboring nanoparticles of the two metals (Cu and Fe) occurring during the IPD layers growth.

48

Inference for impulse responses  

OpenAIRE

Poor identification of individual impulse response coefficients does not necessarily mean that an impulse response is imprecisely estimated. This paper introduces a three-pronged approach on how to communicate uncertainty of impulse response estimates: (1) withWald tests of joint significance; (2) with conditional t-tests of individual marginal coefficient significance; and (3) with fan charts based on the percentiles of the joint Wald statistics. The paper also shows how to anchor the impuls...

Jorda?, O?scar

2007-01-01

49

On the Impulse Control of Jump Diffusions  

CERN Document Server

Regularity of the impulse control problem for a non-degenerate $n$-dimensional jump diffusion with infinite activity and finite variation jumps was recently examined by Davis, Guo, and Wu (SICON 2010). Here we extend the analysis to include infinite activity and infinite variation jumps. More specifically, we show that the value function $u$ of the impulse control problem satisfies $u\\in W^{2,p}_{\\mathrm{loc}}(\\mathbb{R}^{n})$.

Bayraktar, Erhan; Menaldi, Jose-Luis

2012-01-01

50

Risk Factors and Impulsivity in Obesity  

Directory of Open Access Journals (Sweden)

Full Text Available In addition to genetic tendency, social, cultural, emotional and diet-related factors play important role in the development of obesity. Impulsivity is the possible predictor of relapse in obesity treatment. Impulsivity is also considered as a predicting factor among patients who quit the treatment. Research has shown that obese people are more impulsive than other people. Impulsive features are especially found to be higher with those who have binge eating disorder. Impulsive people appears to have no control over their behaviors on eating and they have more interest towards food with higher calories. Another issue that strengthens the assocaition between obesity and impulsivity is the obesity in children with attention deficit hyperactivity disorder. Dopaminergic deficiency in the reward centre of the brain can be a common pathway for both attention deficit and obesity. Several approaches have been searched and put forward to sustain the patients’ lost weights after diet. Specific cognitive behavioral approaches developed for the treatment of impulsive behavior could contribute much into obesity treatment . Obesity is a chronic disease that requires long term treatment and follow up.

Bilge Burcak Annagur

2010-12-01

51

Impulsivity and Academic Cheating  

Science.gov (United States)

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…

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

2009-01-01

52

Impulsivity and Its Treatment  

Directory of Open Access Journals (Sweden)

Full Text Available Identification, description and therapeutic management of impulsivity, which underlies the mechanism and coexistence of many neurological and psychiatric diseases, are considered to be very crucial. Treatment can be applied in two ways; either for the disorder that occurs with impulsivity or for the treatment of the impulsive behavior itself. Disorders associated with or accompanied by impulsivity can be classified as borderline and antisocial personality disorders, schizophrenia, bipolar disorder, attention deficit and hyperactivity disorder, eating disorders, substance use disorders. In addition, impulsivity can manifest itself within the context of diagnostic criteria implicated in the impulse control disorders which include pathological gambling, intermittent explosive disorder, pyromania, kleptomania and trichotillomania. Behavioral and pharmacological interventions that are effective in treatment plans for these disorders should be integrated. These can be listed as insight-oriented psychotherapy and cognitive-behavioral psychotherapies, contingency management, and pharmacotherapy. The aim of the current review is to understand impulsivity and discuss its relation to other psychiatric disorders and to focus on the treatment of impulsivity.

P?nar Güzel Özdemir

2012-09-01

53

A Weakly Nonlinear Analysis of Impulsively-Forced Faraday Waves  

CERN Document Server

Parametrically-excited surface waves, forced by a periodic sequence of delta-function impulses, are considered within the framework of the Zhang-Vi\\~nals model (J. Fluid Mech. 1997). The exact impulsive-forcing results, in the linear and weakly nonlinear regimes, are compared with numerical results for sinusoidal and multifrequency forcing. We find surprisingly good agreement between impulsive forcing results and those obtained using a two-term truncated Fourier series representation of the impulsive forcing function. As noted previously by Bechhoefer and Johnson (Am. J. Phys. 1996), in the case of two equally-spaced impulses per period there are only subharmonic modes of instability. The familiar situation of alternating subharmonic and harmonic resonance tongues emerges for unequally-spaced impulses. We extend the linear analysis for two impulses per period to the weakly nonlinear regime for one-dimensional waves. Specifically, we derive an analytic expression for the cubic Landau coefficient in the bifurca...

Catlla, A; Silber, M; Catlla, Anne; Porter, Jeff; Silber, Mary

2005-01-01

54

Modulation of the dephasing time for a magnetoplasma in a quantum well  

Science.gov (United States)

We investigate the femtosecond kinetics of optically excited 2D magneto-plasma. We calculate the femtosecond dephasing and relaxation kinetics of the laser pulse excited magneto-plasma due to bare Coulomb potential scattering, because screening is under these conditions of minor importance. By taking into account four Landau subbands in both the conduction band and the valence band, we are now able to extend our earlier study [ Phys. Rev. B58, 1998, in press] to lower magnetic fields. We can also fix the magnetic field and change the detuning to further investigate the carrier density-dependence of the dephasing time. For both cases, we predict strong modulation in the dephasing time.

Wu, M. W.; Haug, H.

1998-11-01

55

Nonlinear Theory for a Quantum Diode in a Dense Fermi Magnetoplasma  

International Nuclear Information System (INIS)

We present a simple analytical nonlinear theory for quantum diodes in a dense Fermi magnetoplasma. By using the steady-state quantum hydrodynamical equations for a dense Fermi magnetoplasma, we derive coupled nonlinear Schoedinger and Poisson equations. The latter are numerically solved to show the effects of the quantum statistical pressure, the quantum tunneling (or the quantum diffraction), and the external magnetic field strength on the potential and electron density profiles in a quantum diode at nanometer scales. It is found that the quantum statistical pressure introduces a lower bound on the steady electron flow in the quantum diode, while the quantum diffraction effect allows the electron tunneling at low flow speeds. The magnetic field acts as a barrier, and larger potentials are needed to drive currents through the quantum diode

56

Outer atmosphere and wake of space objects, kinetic simulation. Disturbances of ambient magnetoplasma due to diffuse reflecting bodies in motion  

Science.gov (United States)

Problems of the kinetic simulation of charged and neutral particle flows due to interactions of bodies with space magnetoplasma are dealt with. The image method (see [1], [2]) is considered in application to modeling disturbances of space plasma. The specific case of diffuse reflection of any particle impinging on the object surface is simulated in detail. As applications of the method, simple analytical expressions have been obtained for the far disturbances of the ion concentration due to the diffuse reflecting plate motion at an arbitrary angle to the ambient magnetic field. Different directions of the motion with respect to the plate normal are considered. Disturbances of charged particle concentration are calculated using numerical and analytical methods. The surfaces of constant disturbances are plotted. This work with previous author's results allow the following conclusions: (i) both different interactions with surfaces and ambient electric, magnetic fields can have strong impacts on disturbances due to moving surfaces (ii) these impacts are simulated by kinetic equations which can be solved by numerically and in some specific cases analytically. [1] Physical Review E, v.54, 5591-5598, 1996 [2] Planetary and Space Science, v.43, 1409-1418, 1419-1427, 1995

Ponomarjov, Maxim

1998-11-01

57

Numerical study of the magnetic electron drift vortex mode turbulence in a nonuniform magnetoplasma  

OpenAIRE

A simulation study of the magnetic electron drift vortex (MEDV) mode turbulence in a magnetoplasma in the presence of inhomogeneities in the plasma temperature and density, as well as in the external magnetic field, is presented. The study shows that the influence of the magnetic field inhomogeneity is to suppress streamer-like structures observed in previous simulation studies without background magnetic fields. The MEDV mode turbulence exhibits non-universal (non-Kolmogoro...

Shaikh, Dastgeer; Eliasson, B.; Shukla, P. K.

2009-01-01

58

Theoretical analysis of the resonance cone in an inhomogeneous magnetoplasma column  

International Nuclear Information System (INIS)

The three dimensional behaviour of the high frequency resonance cone is investigated using an inhomogeneous slab magnetoplasma model under the quasistatic approximation and neglecting ion motion. The effects of finite k sub(y) and electron thermal motion are considered numerically, revealing that the cone angle is shifted to a slightly smaller angle and the reflection point also shifts toward the high density region compared with the results under the cold plasma approximation. (author)

59

Vector dissipativity theory for large-scale impulsive dynamical systems  

Directory of Open Access Journals (Sweden)

Full Text Available Modern complex large-scale impulsive systems involve multiple modes of operation placing stringent demands on controller analysis of increasing complexity. In analyzing these large-scale systems, it is often desirable to treat the overall impulsive system as a collection of interconnected impulsive subsystems. Solution properties of the large-scale impulsive system are then deduced from the solution properties of the individual impulsive subsystems and the nature of the impulsive system interconnections. In this paper, we develop vector dissipativity theory for large-scale impulsive dynamical systems. Specifically, using vector storage functions and vector hybrid supply rates, dissipativity properties of the composite large-scale impulsive systems are shown to be determined from the dissipativity properties of the impulsive subsystems and their interconnections. Furthermore, extended Kalman-Yakubovich-Popov conditions, in terms of the impulsive subsystem dynamics and interconnection constraints, characterizing vector dissipativeness via vector system storage functions, are derived. Finally, these results are used to develop feedback interconnection stability results for large-scale impulsive dynamical systems using vector Lyapunov functions.

Haddad Wassim M.

2004-01-01

60

Test-retest reliability of behavioral measures of impulsive choice, impulsive action, and inattention.  

Science.gov (United States)

Behavioral measures of impulsivity are widely used in substance abuse research, yet relatively little attention has been devoted to establishing their psychometric properties, especially their reliability over repeated administration. The current study examined the test-retest reliability of a battery of standardized behavioral impulsivity tasks, including measures of impulsive choice (i.e., delay discounting, probability discounting, and the Balloon Analogue Risk Task), impulsive action (i.e., the stop signal task, the go/no-go task, and commission errors on the continuous performance task), and inattention (i.e., attention lapses on a simple reaction time task and omission errors on the continuous performance task). Healthy adults (n = 128) performed the battery on two separate occasions. Reliability estimates for the individual tasks ranged from moderate to high, with Pearson correlations within the specific impulsivity domains as follows: impulsive choice (r range: .76-.89, ps tasks. Change in performance on the delay discounting task was significantly associated with change in positive mood and arousal. No other behavioral measures were significantly associated with mood. In sum, the current analysis demonstrates that behavioral measures of impulsivity are reliable measures and thus can be confidently used to assess various facets of impulsivity as intermediate phenotypes for drug abuse. PMID:24099351

Weafer, Jessica; Baggott, Matthew J; de Wit, Harriet

2013-12-01

61

An Exploration of Apathy and Impulsivity in Parkinson Disease  

OpenAIRE

Background. Apathy and impulsivity in Parkinson disease (PD) are associated with clinically significant behavioral disorders. Aim. To explore the phenomenology, distribution, and clinical correlates of these two behaviors. Methods. In PD participants (n = 99) without dementia we explored the distribution of measures of motivation and impulsivity using univariate methods. We then undertook factor analysis to define specific underlying dimensions of apathy and impulsivity. Regression models...

Ahearn, David J.; Kathryn McDonald; Michelle Barraclough; Iracema Leroi

2012-01-01

62

Effects of the cannabinoid CB1 receptor antagonist rimonabant on distinct measures of impulsive behavior in rats  

OpenAIRE

Rationale Pathological impulsivity is a prominent feature in several psychiatric disorders, but detailed understanding of the specific neuronal processes underlying impulsive behavior is as yet lacking. Objectives As recent findings have suggested involvement of the brain cannabinoid system in impulsivity, the present study aimed at further elucidating the role of cannabinoid CB1 receptor activation in distinct measures of impulsive behavior. Ma...

Vries, Taco; Gonzalez-cuevas, Gustavo; Janssen, Mieke; Pattij, Tommy; Schepers, Inga; Schoffelmeer, Anton

2007-01-01

63

Excitation of shear Alfvén waves by a spiraling ion beam in a large magnetoplasma  

Science.gov (United States)

Generation of shear Alfvén waves by the Doppler-shifted ion-cyclotron-resonance (DICR) of a spiraling H+ ion beam with magnetic fluctuations in a dual-species magnetized plasma with He+ and H+ ions has been investigated on the Large Plasma Device. The ambient plasma density and electron temperature were significantly enhanced by the beam. The Alfvén waves were left-handed polarized and traveled in the direction opposite to the ion beam. This is the first experimental demonstration of the DICR excitation of traveling shear Alfvén waves in a laboratory magnetoplasma.

Tripathi, S. K. P.; Van Compernolle, B.; Gekelman, W.; Pribyl, P.; Heidbrink, W.

2015-01-01

64

Impulsivity and rapid decision-making for reward  

Directory of Open Access Journals (Sweden)

Full Text Available Impulsivity is a feature of many brain disorders. Although often defined as the predisposition to act with an inadequate degree of deliberation, forethought or control, it has proven difficult to measure. This may in part be because, increasingly, impulsivity is recognized as a multifaceted construct, with impulsive decisions potentially arising due to a number of underlying mechanisms. Indeed, in certain contexts, a ‘functional’ degree of impulsivity may promote effective, motivated behavior in healthy participants. Although many tasks have been developed to study impulsivity, few examine decisions made rapidly, for time-sensitive rewards: In this context, a degree of impulsivity may be adaptive. In the current study we examine behavior in 59 adults on a manual ‘Traffic Light’ task which requires participants to take risks under time pressure, if they are to maximize reward. We show that behavioral variables that index rapid anticipatory responding in this paradigm are correlated with a specific self-report measure of impulsivity: ‘lack of premeditation’ on the UPPS Impulsive Behavior Scale. Participants who scored more highly on this subscale performed better on the task. Moreover, anticipatory behavior reduced significantly with age (18-79 years, an effect that continued to be upheld after correction for potential age differences in the ability to judge the timing of responses. Based on these findings, we argue that the Traffic Light task provides a parametric method to study a ‘functional’ aspect of impulsivity in health and disease: namely, rapid decision-making in pursuit of risky, time-sensitive rewards.

StephanieBurnett Heyes

2012-05-01

65

Relativistic impulse dynamics.  

Science.gov (United States)

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. PMID:21929132

Swanson, Stanley M

2011-08-01

66

Choice impulsivity: Definitions, measurement issues, and clinical implications.  

Science.gov (United States)

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. (PsycINFO Database Record PMID:25867841

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

67

Modulation of drift-wave envelopes in a nonuniform quantum magnetoplasma  

Energy Technology Data Exchange (ETDEWEB)

We study the amplitude modulation of low-frequency, long-wavelength electrostatic drift-wave envelopes in a nonuniform quantum magnetoplasma consisting of cold ions and degenerate electrons. The effects of tunneling associated with the quantum Bohm potential and the Fermi pressure for nonrelativistic degenerate electrons, as well as the equilibrium density and magnetic field inhomogeneities are taken into account. Starting from a set of quantum magnetohydrodynamic equations, we derive a nonlinear Schrödinger equation (NLSE) that governs the dynamics of the modulated quantum drift-wave packets. The NLSE is used to study the modulational instability (MI) of a Stoke's wave train to a small plane wave perturbation. It is shown that the quantum tunneling effect as well as the scale length of inhomogeneity plays crucial roles for the MI of the drift-wave packets. Thus, the latter can propagate in the form of bright and dark envelope solitons or as drift-wave rogons in degenerate dense magnetoplasmas.

Misra, A. P., E-mail: apmisra@visva-bharati.ac.in, E-mail: apmisra@gmail.com [Department of Mathematics, Siksha Bhavana, Visva-Bharati University, Santiniketan-731 235, West Bengal (India)

2014-04-15

68

Modulation of drift-wave envelopes in a nonuniform quantum magnetoplasma  

CERN Document Server

We study the amplitude modulation of low-frequency, long-wavelength electrostatic drift-wave envelopes in a nonuniform quantum magnetoplasma consisting of cold ions and degenerate electrons. The effects of tunneling associated with the quantum Bohm potential and the Fermi pressure for nonrelativistic degenerate electrons, as well as the equilibrium density and magnetic field inhomogeneities are taken into account. Starting from a set of quantum magnetohydrodynamic (QMHD) equations, we derive a nonlinear Schr\\"odinger equation (NLSE) that governs the dynamics of the modulated quantum drift-wave packets. The NLSE is used to study the modulational instability (MI) of a Stoke's wave train to a small plane wave perturbation. It is shown that the quantum tunneling effect as well as the scale length of inhomogeneity play crucial roles for the MI of the drift-wave packets. Thus, the latter can propagate in the form of bright and dark envelope solitons or as drift-wave rogons in degenerate dense magnetoplasmas.

Misra, A P

2014-01-01

69

Micropower impulse radar imaging  

Energy Technology Data Exchange (ETDEWEB)

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.

Hall, M.S.

1995-11-01

70

Sleep patterns and impulse control among Japanese junior high school students.  

Science.gov (United States)

Adolescents with decreased impulse control exhibit behavioral problems. Lifestyles are related to impulse control. However, the relations of sleep patterns and impulse control among adolescents are unknown. Thus we examined how sleep patterns were associated with impulse control among Japanese junior high school students. Surveys were completed by a nationwide sample of 1934 students. A significant association between decreased impulse control and bedtimes after midnight was revealed. Specific lifestyle factors related to bedtimes after midnight were older age, greater numbers of hours spent watching television, lack of participation in an extracurricular activity, greater use of convenience stores, and increased attendance at cram schools. This study revealed that going to sleep after midnight was significantly related to decreased impulse control among adolescents. Data about specific lifestyle factors related to going to sleep after midnight should be useful in preventing those behaviors demonstrated by school children that derive from decreased impulse control. PMID:20005566

Abe, Takeru; Hagihara, Akihito; Nobutomo, Koichi

2010-10-01

71

Absorption of intense Gaussian electromagnetic radiation in a magnetoplasma via inverse bremsstrahlung  

International Nuclear Information System (INIS)

A self-focused Gaussian laser beam propagating in the direction of static magnetic field in a collisional magnetoplasma has been considered. The explicit expressions for the time averaged power absorbed for left and right handed circularly polarised waves have been obtained. The effect of magnetic field and focusing on the rate of power absorbed is studied in weak field regime (?sub(E) > ?sub(Th)). It is observed that the rate of absorption of right circularly polarised radiation decreases whereas for left circularly polarised radiation increases in weak field regime whereas reverse holds good in strong field regime. It is also observed that the increase in magnetic field decreases the focussing length for right circularly polarised wave whereas defocusses the left circularly polarised wave and power absorption for both the modes shows a typical behaviour due to coupling between them. (author)

72

Electron acoustic wave driven vortices with non-Maxwellian hot electrons in magnetoplasmas  

Energy Technology Data Exchange (ETDEWEB)

Linear dispersion characteristics of the Electron Acoustic Wave (EAW) and the corresponding vortex structures are investigated in a magnetoplasma in the presence of non-Maxwellian hot electrons. In this regard, kappa and Cairns distributed hot electrons are considered. It is noticed that the nonthermal distributions affect the phase velocity of the EAW. Further, it is found that the phase velocity of EAW increases for Cairns and decreases for kappa distributed hot electrons. Nonlinear solutions in the form of dipolar vortices are also obtained for both stationary and non-stationary ions in the presence of kappa distributed hot electrons and dynamic cold electrons. It is found that the amplitude of the nonlinear vortex structures also reduces with kappa factor like the electron acoustic solitons.

Haque, Q. [Theoretical Physics Division, PINSTECH, P. O. Nilore, Islamabad (Pakistan); National Center for Physics Shahdrah Valley Road, Islamabad 44000 (Pakistan); Mirza, Arshad M. [Theoretical Plasma Physics Group, Department of Physics, Quaid-i-Azam University, Islamabad 45320 (Pakistan); Zakir, U. [Institute of Physics and Electronics, University of Peshawar, and Khyber Pakhtun Khwa 25000 (Pakistan); Department of Physics, University of Malakand Chakdara Dir(L), Khyber Pakhtun Khwa 18800 Pakistan (Pakistan)

2014-07-15

73

Dust kinetic Alfvén waves and streaming instability in a non-Maxwellian magnetoplasma  

Energy Technology Data Exchange (ETDEWEB)

The dust kinetic Alfvén wave (DKAW) instability is studied in a uniform dusty magnetoplasma by incorporating the superthermality effects of the electrons and perpendicularly streaming ?-distributed ions. The dispersion relation of the DKAW instability is investigated in the low-?{sub d} Lorentzian plasma limit. The solutions are analyzed for various scenarios of dusty and dusty-free plasmas. It is shown that the presence of dust particles and the cross-field superthermal ions sensibly modify the dispersion characteristics of the low-frequency DKAW. The present results are only valid for a frequency regime well below the dust cyclotron frequency. Numerical calculations are carried out for the growth rates by taking different dust parameters into account. It is found that the nonthermality is more effective for the dust kinetic Alfvén waves in the perpendicular direction as compared to the parallel one. The relevance of the results to the low-?{sub d} regions of space and astrophysical plasmas is highlighted.

Rubab, N.; Jaffer, G. [Department of Space Science, Institute of Space Technology (IST), Islamabad Expressway, Islamabad 44000 (Pakistan); Ali, S. [National Centre for Physics (NCP) at Quaid-i-Azam University Campus, Shahdra Valley Road, Islamabad 44000 (Pakistan)

2014-06-15

74

Electron acoustic wave driven vortices with non-Maxwellian hot electrons in magnetoplasmas  

International Nuclear Information System (INIS)

Linear dispersion characteristics of the Electron Acoustic Wave (EAW) and the corresponding vortex structures are investigated in a magnetoplasma in the presence of non-Maxwellian hot electrons. In this regard, kappa and Cairns distributed hot electrons are considered. It is noticed that the nonthermal distributions affect the phase velocity of the EAW. Further, it is found that the phase velocity of EAW increases for Cairns and decreases for kappa distributed hot electrons. Nonlinear solutions in the form of dipolar vortices are also obtained for both stationary and non-stationary ions in the presence of kappa distributed hot electrons and dynamic cold electrons. It is found that the amplitude of the nonlinear vortex structures also reduces with kappa factor like the electron acoustic solitons

75

Numerical study of the magnetic electron drift vortex mode turbulence in a nonuniform magnetoplasma  

International Nuclear Information System (INIS)

A simulation study of the magnetic electron drift vortex (MEDV) mode turbulence in a magnetoplasma in the presence of inhomogeneities in the plasma temperature and density, as well as in the external magnetic field, is presented. The study shows that the influence of the magnetic field inhomogeneity is to suppress streamerlike structures observed in previous simulation studies without background magnetic fields. The MEDV mode turbulence exhibits nonuniversal (non-Kolmogorov-type) spectra for different sets of the plasma parameters. In the presence of an inhomogeneous magnetic field, the spectrum changes to a 7/3 power law, which is flatter than without magnetic field gradients. The relevance of this work to laser-produced plasmas in the laboratory is briefly mentioned.

76

Numerical study of the magnetic electron drift vortex mode turbulence in a nonuniform magnetoplasma  

CERN Document Server

A simulation study of the magnetic electron drift vortex (MEDV) mode turbulence in a magnetoplasma in the presence of inhomogeneities in the plasma temperature and density, as well as in the external magnetic field, is presented. The study shows that the influence of the magnetic field inhomogeneity is to suppress streamer-like structures observed in previous simulation studies without background magnetic fields. The MEDV mode turbulence exhibits non-universal (non-Kolmogorov type) spectra for different sets of the plasma parameters. In the presence of an inhomogeneous magnetic field, the spectrum changes to a 7/3 power law, which is flatter than without magnetic field gradients. The relevance of this work to laser-produced plasmas in the laboratory is briefly mentioned.

Shaikh, Dastgeer; Shukla, P K

2009-01-01

77

Impulse Detectors for Noised Sequences  

Directory of Open Access Journals (Sweden)

Full Text Available This paper is focused on a problem of impulse detection in thedynamic image environments corrupted by impulse noise. Using a proposedarchitecture that includes an impulse detector and the median filter,the effective methods can be designed. Thus, the image points areclassified into two classes such as a class of noise free samples and aclass of noised image points. In the case of impulse detection theestimate is performed by a median filter whereas a noise free sample ispassed on the output without the change i.e. system works as anidentity filter.

R. Lukac

2001-06-01

78

Facets of impulsivity interactively predict body fat and binge eating in young women.  

Science.gov (United States)

Impulsivity has been positively linked to overeating and obesity, but findings are inconsistent. Studies using the Barratt Impulsiveness Scale (BIS) show that measures of overeating appear to be most consistently associated with scores on the subscale attentional impulsivity in both non-clinical and clinical samples. Additionally, individuals with binge-eating behaviors may have elevated scores on the subscale motor impulsivity. In the current study, young women (N?=?133) completed the short form of the BIS (BIS-15), the Eating Disorder Examination - Questionnaire, and height, weight and body composition were measured. Regression analyses showed that attentional and motor impulsivity positively predicted binge eating and general eating pathology, while non-planning impulsivity negatively predicted these variables. Moreover, attentional and motor impulsivity interactively predicted percent body fat, and the number of subjective and objective binge episodes. Results show that only specific aspects of trait impulsivity (attentional and motor impulsivity) are positively associated with body mass and binge eating. Non-planning impulsivity appears to be unrelated or even inversely related to those variables, at least in female students. Elevated levels of attentional impulsivity in conjunction with high motor impulsivity may be a risk factor for overweight and clinically relevant binge eating. PMID:25582417

Meule, Adrian; Platte, Petra

2015-04-01

79

Multi-dimensional instability of obliquely propagating ion acoustic solitary waves in electron-positron-ion superthermal magnetoplasmas  

International Nuclear Information System (INIS)

The solitary structures of multi–dimensional ion-acoustic solitary waves (IASWs) have been considered in magnetoplasmas consisting of electron-positron-ion with high-energy (superthermal) electrons and positrons are investigated. Using a reductive perturbation method, a nonlinear Zakharov-Kuznetsov equation is derived. The multi-dimensional instability of obliquely propagating (with respect to the external magnetic field) IASWs has been studied by the small-k (long wavelength plane wave) expansion perturbation method. The instability condition and the growth rate of the instability have been derived. It is shown that the instability criterion and their growth rate depend on the parameter measuring the superthermality, the ion gyrofrequency, the unperturbed positrons-to-ions density ratio, the direction cosine, and the ion-to-electron temperature ratio. Clearly, the study of our model under consideration is helpful for explaining the propagation and the instability of IASWs in space observations of magnetoplasmas with superthermal electrons and positrons

80

A comparison of parametric decay of oblique Langmuir wave in high and low density magneto-plasmas  

Science.gov (United States)

The parametric decay instability of an obliquely propagating Langmuir wave into the low-frequency electromagnetic shear Alfven wave and the Left-Handed Circularly Polarized wave has been investigated in an electron-ion plasma, immersed in a uniform external magnetic field. Quantum magneto-hydrodynamic model has been used to find the linear and non-linear response of a high density quantum magneto-plasma. Going to the classical limit (??0) retrieves the results for low density classical plasma. Nonlinear dispersion relations and growth rates are derived with analytically and numerically. It is observed that growth rate in the high density degenerate magneto-plasma increases exponentially, while in the low density classical case it increases logarithmically.

Shahid, M.; Hussain, A.; Murtaza, G.

2013-09-01

81

Dynamic behavior of ion acoustic waves in electron-positron-ion magnetoplasmas with superthermal electrons and positrons  

International Nuclear Information System (INIS)

The dynamic behavior of ion acoustic waves in electron-positron-ion magnetoplasmas with superthermal electrons and positrons has been investigated in the framework of perturbed and non-perturbed Kadomtsev-Petviashili (KP) equations. Applying the reductive perturbation technique, we have derived the KP equation in electron-positron-ion magnetoplasma with kappa distributed electrons and positrons. Bifurcations of ion acoustic traveling waves of the KP equation are presented. Using the bifurcation theory of planar dynamical systems, the existence of the solitary wave solutions and the periodic traveling wave solutions has been established. Two exact solutions of these waves have been derived depending on the system parameters. Then, using the Hirota's direct method, we have obtained two-soliton and three-soliton solutions of the KP equation. The effect of the spectral index ? on propagations of the two-soliton and the three-soliton has been shown. Considering an external periodic perturbation, we have presented the quasi periodic behavior of ion acoustic waves in electron-positron-ion magnetoplasmas

82

Dynamic behavior of ion acoustic waves in electron-positron-ion magnetoplasmas with superthermal electrons and positrons  

Energy Technology Data Exchange (ETDEWEB)

The dynamic behavior of ion acoustic waves in electron-positron-ion magnetoplasmas with superthermal electrons and positrons has been investigated in the framework of perturbed and non-perturbed Kadomtsev-Petviashili (KP) equations. Applying the reductive perturbation technique, we have derived the KP equation in electron-positron-ion magnetoplasma with kappa distributed electrons and positrons. Bifurcations of ion acoustic traveling waves of the KP equation are presented. Using the bifurcation theory of planar dynamical systems, the existence of the solitary wave solutions and the periodic traveling wave solutions has been established. Two exact solutions of these waves have been derived depending on the system parameters. Then, using the Hirota's direct method, we have obtained two-soliton and three-soliton solutions of the KP equation. The effect of the spectral index ? on propagations of the two-soliton and the three-soliton has been shown. Considering an external periodic perturbation, we have presented the quasi periodic behavior of ion acoustic waves in electron-positron-ion magnetoplasmas.

Saha, Asit, E-mail: asit-saha123@rediffmail.com, E-mail: prasantachatterjee1@rediffmail.com [Department of Mathematics, Sikkim Manipal Institute of Technology, Majitar, Rangpo, East-Sikkim 737136 (India); Department of Mathematics, Siksha Bhavana, Visva Bharati University, Santiniketan-731235 (India); Pal, Nikhil; Chatterjee, Prasanta, E-mail: asit-saha123@rediffmail.com, E-mail: prasantachatterjee1@rediffmail.com [Department of Mathematics, Siksha Bhavana, Visva Bharati University, Santiniketan-731235 (India)

2014-10-15

83

Impulsivity, gender, and the platelet serotonin transporter in healthy subjects  

Directory of Open Access Journals (Sweden)

Full Text Available Donatella Marazziti, Stefano Baroni, Irene Masala, Francesca Golia, Giorgio Consoli, Gabriele Massimetti, Michela Picchetti, Mario Catena Dell’Osso, Gino Giannaccini, Laura Betti, Antonio Lucacchini, Antonio CiapparelliDipartimento di Psichiatria, Neurobiologia, Farmacologia e Biotecnologie, University of Pisa, Pisa, ItalyAbstract: The present study explored the possible relationships between impulsivity, gender, and a peripheral serotonergic marker, the platelet serotonin (5-HT transporter (SERT, in a group of 32 healthy subjects. The impulsivity was measured by means of the Barratt Impulsivity Scale, version 11 (BIS-11, a widely used self-report questionnaire, and the platelet SERT was evaluated by means of the specific binding of 3H-paroxetine (3H-Par to platelet membranes, according to standardized protocols. The results showed that women had a higher BIS-11 total score than men, and also higher scores of two factors of the same scale: the motor impulsivity and the cognitive complexity. The analysis of the correlations revealed that the density of the SERT proteins, as measured by the maximum binding capacity (Bmax of 3H-Par, was significantly and positively related to the cognitive complexity factor, but only in men. Men showed also a significant and negative correlation with the dissociation constant, Kd, of (3H-Par binding, and the motor impulsivity factor. These findings suggest that women are generally more impulsive than men, but that the 5-HT system is more involved in the impulsivity of men than in that of women.Keywords: impulsivity, gender, serotonin transporter, Barratt Impulsivity Scale, platelets, 3H-paroxetine

Donatella Marazziti

2009-12-01

84

Impulsivity in disorders of food and drug misuse.  

Science.gov (United States)

Background. Evidence suggests some overlap between the pathological use of food and drugs, yet how impulsivity compares across these different clinical disorders remains unclear. Substance use disorders are commonly characterized by elevated impulsivity, and impulsivity subtypes may show commonalities and differences in various conditions. We hypothesized that obese subjects with binge-eating disorder (BED) and abstinent alcohol-dependent cohorts would have relatively more impulsive profiles compared to obese subjects without BED. We also predicted decision impulsivity impairment in obesity with and without BED. Method. Thirty obese subjects with BED, 30 without BED and 30 abstinent alcohol-dependent subjects and age- and gender-matched controls were tested on delay discounting (preference for a smaller immediate reward over a larger delayed reward), reflection impulsivity (rapid decision making prior to evidence accumulation) and motor response inhibition (action cancellation of a prepotent response). Results. All three groups had greater delay discounting relative to healthy volunteers. Both obese subjects without BED and alcohol-dependent subjects had impaired motor response inhibition. Only obese subjects without BED had impaired integration of available information to optimize outcomes over later trials with a cost condition. Conclusions. Delay discounting appears to be a common core impairment across disorders of food and drug intake. Unexpectedly, obese subjects without BED showed greater impulsivity than obese subjects with BED. We highlight the dissociability and heterogeneity of impulsivity subtypes and add to the understanding of neurocognitive profiles across disorders involving food and drugs. Our results have therapeutic implications suggesting that disorder-specific patterns of impulsivity could be targeted. PMID:25118940

Mole, T B; Irvine, M A; Worbe, Y; Collins, P; Mitchell, S P; Bolton, S; Harrison, N A; Robbins, T W; Voon, V

2015-03-01

85

Impulse Generation Mechanism in Glycerin Propellant Laser Thruster  

International Nuclear Information System (INIS)

A sequential process from pulsed laser irradiation onto a spherical liquid propellant to impulse generation is discussed toward higher specific impulse performance of the thruster. A Q-switched 10-ns Nd: YAG laser pulse with 1 ?m wavelength was focused in a 2-mm diameter glycerin droplet in vacuum condition (?10 Pa). Visible image of the droplet shot with the laser pulse, laser energy transmitted through the droplet, emission spectrum in visible to near infrared region, and temporal impulse behavior measured with piezoelectric devices were obtained. It is found that the impulse generation mechanism can be divided into energy deposition on the surface and inside of the droplet, and subsequent explosion of the droplet, depending on laser irradiation conditions

86

Impulse regulation in anorexia nervosa and bulimia nervosa: some formulations.  

Science.gov (United States)

Empirical observations imply that impulsivity is specifically associated with poor prognosis in eating disorders. The present paper cites studies suggesting that this factor is predominantly associated with the bulimic pattern of eating disturbance, while "restriction" may be associated rather with hypercontrol of behaviour. Further evidence is cited suggesting that the relationship between hyper- and hypocontrol is actually very intimate, both on a behavioural and biochemical level. Rather than bulimics being generally impulsive and "restrictors" generally hypercontrolled, future studies may reveal impulse regulation difficulties of both kinds in both groups. Single-minded preoccupation with dieting may be an ill-equipped individual's effort to simplify life in periods of change and environmental challenge that demand capacity for flexible impulse regulation. PMID:24487502

Sohlberg, S

1991-01-01

87

High-intensity drying processes: Impulse drying. Annual report  

Energy Technology Data Exchange (ETDEWEB)

Experiments were conducted on a sheet-fed pilot-scale shoe press to compare impulse drying and double-felted pressing. Both an IPST (Institute of Paper Science and Technology) ceramic coated and Beloit Type A press roll were evaluated for lienrboard sheet structures having a wide range of z-direction permeability. Purpose was to find ways of correcting sheet sticking problems observed in previous pilot-scale shoe press experiments. Results showed that impulse drying was superior to double felted pressing in both press dryness and in important paper physical properties. Impulse drying critical temperature was found to depend on specific surface of the heated layer of the sheet, thermal properties of the press roll surface, and choice of felt. Impulse drying of recycled and two-ply liner was demonstrated for both Southern Pile and Douglas fir-containing furnishes.

Orloff, D.I.; Phelan, P.M.

1993-12-01

88

Dynamic behavior of the quantum Zakharov-Kuznetsov equations in dense quantum magnetoplasmas  

International Nuclear Information System (INIS)

Quantum Zakharov-Kuznetsov (qZK) equation is found in a dense quantum magnetoplasma. Via the spectral analysis, we investigate the Hamiltonian and periodicity of the qZK equation. Using the Hirota method, we obtain the bilinear forms and N-soliton solutions. Asymptotic analysis on the two-soliton solutions shows that the soliton interaction is elastic. Figures are plotted to reveal the propagation characteristics and interaction between the two solitons. We find that the one soliton has a single peak and its amplitude is positively related to He, while the two solitons are parallel when He?e is proportional to the ratio of the strength of magnetic field to the electronic Fermi temperature. External periodic force on the qZK equation yields the chaotic motions. Through some phase projections, the process from a sequence of the quasi-period doubling to chaos can be observed. The chaotic behavior is observed since the power spectra are calculated, and the quasi-period doubling states of perturbed qZK equation are given. The final chaotic state of the perturbed qZK is obtained

89

Electric field variability and classifications of Titan's magnetoplasma environment  

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Full Text Available The atmosphere of Saturn's largest moon Titan is driven by photochemistry, charged particle precipitation from Saturn's upstream magnetosphere, and presumably by the diffusion of the magnetospheric field into the outer ionosphere, amongst other processes. Ion pickup, controlled by the upstream convection electric field, plays a role in the loss of this atmosphere. The interaction of Titan with Saturn's magnetosphere results in the formation of a flow-induced magnetosphere. The upstream magnetoplasma environment of Titan is a complex and highly variable system and significant quasi-periodic modulations of the plasma in this region of Saturn's magnetosphere have been reported. In this paper we quantitatively investigate the effect of these quasi-periodic modulations on the convection electric field at Titan. We show that the electric field can be significantly perturbed away from the nominal radial orientation inferred from Voyager 1 observations, and demonstrate that upstream categorisation schemes must be used with care when undertaking quantitative studies of Titan's magnetospheric interaction, particularly where assumptions regarding the orientation of the convection electric field are made.

C. S. Arridge

2011-07-01

90

Determination of carrier mobility and density in semiconductors by the contactless magnetoplasma methods  

International Nuclear Information System (INIS)

Considered are new contactless electromagnetic magnetoplasma methods for investigating conductivity parameters in semiconductors in the region of classically weak (BB approximately 1) magnetic fields. A semiconductor is placed into a constant magnetic field but, unlike the Hall measurements where determined are electric field components in a semiconductor with current, measurements according to the new methods include the contactless determination of the components of a variable magnetic field excited in the semiconductor. The case of an isotropic semiconductor was considered. It is shown that the new methods permit to determine the Hall mobility and charge carrier concentration in the region of weak magnetic fields. In the region of intermediate fields the factor ?1, included as a multiplier in expressions for experimentally measured nondiagonal component of conductivity tensor, has a simpler dependence on the magnetic field as compared with the Hall factor. This permit to determine drift mobility and exact concentration. Experimental measurements of electron mobility and density in InSb and Ge are given

91

Solitons and shocks in dense astrophysical magnetoplasmas with relativistic degenerate electrons and positrons  

Energy Technology Data Exchange (ETDEWEB)

The linear and nonlinear properties of the ion-acoustic (IA) waves are investigated in a relativistically degenerate magnetoplasma, whose constituents are the electrons, positrons, and ions. The electrons and positrons are assumed to obey the Fermi-Dirac statistics, whereas the cold ions are taken to be inertial and magnetized. In linear analysis, various limiting cases are discussed both analytically and numerically. However, for nonlinear studies, the well-known reductive perturbation technique is employed to derive the Zakharov-Kuznetsov and Zakharov-Kuznetsov Burgers equations in the presence of relativistically degenerate electrons and positrons. Furthermore, with the use of hyperbolic tangent method, the equations are simplified to admit the soliton and shock wave solutions. Numerically, it is shown that the amplitude, width, and phase speed associated with the localized IA solitons and shocks are significantly influenced by the various intrinsic plasma parameters relevant to our model. The present analysis can be useful for understanding the collective processes in dense astrophysical environments like neutron stars, where the electrons and positrons are expected to be relativistic and degenerate.

Ali, S. [National Centre for Physics at QAU Campus, Shahdra Valley Road, Islamabad 44000 (Pakistan); Ata-ur-Rahman [National Centre for Physics at QAU Campus, Shahdra Valley Road, Islamabad 44000 (Pakistan); Institute of Physics and Electronics, University of Peshawar, Peshawar 25000 (Pakistan)

2014-04-15

92

Formation of the compression zone in a plasma flow generated by a magnetoplasma compressor  

International Nuclear Information System (INIS)

Processes occurring in a plasma flow generated by a magnetoplasma compressor (MPC) during the formation of the compression zone are discussed. The paper presents results of measurements of the spatial distribution of the electric current in the plasma flow, the temporal and spatial (along the flow) distributions of the plasma density, and the profiles of the velocity of individual flow layers along the system axis. The spatial distribution of the electromagnetic force in the flow is analyzed. It is shown that the plasma flow is decelerated when approaching the compression zone and reaccelerated after passing it. In this case, the plasma flow velocity decreases from ? = (2–3) × 107 cm/s at the MPC output to ? 6 cm/s in the region of maximum compression and then again increases to 107 cm/s at a distance of 15–17 cm from the MPC output. In some MPC operating modes, a displacement of the magnetic field from the compression zone and the formation of toroidal electric current vortices in the plasma flow after passing the compression zone were detected

93

Dust acoustic solitary and shock excitations in a Thomas-Fermi magnetoplasma  

Energy Technology Data Exchange (ETDEWEB)

The linear and nonlinear properties of dust-acoustic waves are investigated in a collisionless Thomas-Fermi magnetoplasma, whose constituents are electrons, ions, and negatively charged dust particles. At dust time scale, the electron and ion number densities follow the Thomas-Fermi distribution, whereas the dust component is described by the classical fluid equations. A linear dispersion relation is analyzed to show that the wave frequencies associated with the upper and lower modes are enhanced with the variation of dust concentration. The effect of the latter is seen more strongly on the upper mode as compared to the lower mode. For nonlinear analysis, we obtain magnetized Korteweg-de Vries (KdV) and Zakharov-Kuznetsov (ZK) equations involving the dust-acoustic solitary waves in the framework of reductive perturbation technique. Furthermore, the shock wave excitations are also studied by allowing dissipation effects in the model, leading to the Korteweg-de Vries-Burgers (KdVB) and ZKB equations. The analysis reveals that the dust-acoustic solitary and shock excitations in a Thomas-Fermi plasma are strongly influenced by the plasma parameters, e.g., dust concentration, dust temperature, obliqueness, magnetic field strength, and dust fluid viscosity. The present results should be important for understanding the solitary and shock excitations in the environments of white dwarfs or supernova, where dust particles can exist.

Rahim, Z.; Qamar, A. [Institute of Physics and Electronics, University of Peshawar, Peshawar 25000 (Pakistan); National Center for Physics (NCP) at QAU Campus, Shahdra Valley Road, Islamabad 44000 (Pakistan); Ali, S. [National Center for Physics (NCP) at QAU Campus, Shahdra Valley Road, Islamabad 44000 (Pakistan)

2014-07-15

94

Dust acoustic solitary and shock excitations in a Thomas-Fermi magnetoplasma  

International Nuclear Information System (INIS)

The linear and nonlinear properties of dust-acoustic waves are investigated in a collisionless Thomas-Fermi magnetoplasma, whose constituents are electrons, ions, and negatively charged dust particles. At dust time scale, the electron and ion number densities follow the Thomas-Fermi distribution, whereas the dust component is described by the classical fluid equations. A linear dispersion relation is analyzed to show that the wave frequencies associated with the upper and lower modes are enhanced with the variation of dust concentration. The effect of the latter is seen more strongly on the upper mode as compared to the lower mode. For nonlinear analysis, we obtain magnetized Korteweg-de Vries (KdV) and Zakharov-Kuznetsov (ZK) equations involving the dust-acoustic solitary waves in the framework of reductive perturbation technique. Furthermore, the shock wave excitations are also studied by allowing dissipation effects in the model, leading to the Korteweg-de Vries-Burgers (KdVB) and ZKB equations. The analysis reveals that the dust-acoustic solitary and shock excitations in a Thomas-Fermi plasma are strongly influenced by the plasma parameters, e.g., dust concentration, dust temperature, obliqueness, magnetic field strength, and dust fluid viscosity. The present results should be important for understanding the solitary and shock excitations in the environments of white dwarfs or supernova, where dust particles can exist

95

Nonlinear ion-acoustic cnoidal waves in a dense relativistic degenerate magnetoplasma  

Science.gov (United States)

The complex pattern and propagation characteristics of nonlinear periodic ion-acoustic waves, namely, ion-acoustic cnoidal waves, in a dense relativistic degenerate magnetoplasma consisting of relativistic degenerate electrons and nondegenerate cold ions are investigated. By means of the reductive perturbation method and appropriate boundary conditions for nonlinear periodic waves, a nonlinear modified Korteweg-de Vries (KdV) equation is derived and its cnoidal wave is analyzed. The various solutions of nonlinear ion-acoustic cnoidal and solitary waves are presented numerically with the Sagdeev potential approach. The analytical solution and numerical simulation of nonlinear ion-acoustic cnoidal waves of the nonlinear modified KdV equation are studied. Clearly, it is found that the features (amplitude and width) of nonlinear ion-acoustic cnoidal waves are proportional to plasma number density, ion cyclotron frequency, and direction cosines. The numerical results are applied to high density astrophysical situations, such as in superdense white dwarfs. This research will be helpful in understanding the properties of compact astrophysical objects containing cold ions with relativistic degenerate electrons.

El-Shamy, E. F.

2015-03-01

96

Nonlinearly coupled upper-hybrid and magnetoacoustic waves in collisional magnetoplasmas  

International Nuclear Information System (INIS)

The nonlinear interaction between large amplitude electrostatic upper-hybrid (UH) waves and magnetoacoustic perturbations in a collisional magnetoplasma is considered. For this purpose, we present a nonlinear Schroedinger equation for the UH wave envelope in the presence of the electron density, electron temperature, and compressional magnetic field perturbations of the dispersive magnetoacoustic waves, and derive an equation for the latter taking into account the combined influence of the UH ponderomotive force and the differential electron Joule heating in the UH wave electric field. The coupled equations are employed to investigate modulational instabilities of a constant amplitude UH wave, and the density profile modifications due to the UH ponderomotive and thermal forces. It is found that the thermal instability has its maximum at a wavelength half the one of the UH wave, and a numerical solution of the coupled time-dependent system of equations reveals that localized density cavities are also created with a spacing approximately half the wavelength of the pump wave

97

Impulsivity, impulsive and reflective processes and the development of alcohol use and misuse in adolescents and young adults.  

Science.gov (United States)

This paper contrasts dual-process and personality approaches in the prediction of addictive behaviors and related risk behaviors. In dual-process models, behavior is described as the joint outcome of qualitatively different "impulsive" (or associative) and "reflective" processes. There are important individual differences regarding both types of processes, and the relative strength of both in a specific situation is influenced by prior behavior and state variables (e.g., fatigue, alcohol use). From this perspective, a specific behavior (e.g., alcohol misuse) can be predicted by the combined indices of the behavior-related impulsive processes (e.g., associations with alcohol), and reflective processes, including the ability to refrain from a motivationally salient action. Personality approaches have reported that general traits such as impulsivity predict addictive behaviors. Here we contrast these two approaches, with supplementary analyses on four datasets. We hypothesized that trait impulsivity can predict specific risky behaviors, but that its predictive power disappears once specific behavior-related associations, indicators of executive functioning, and their interaction are entered into the equation. In all four studies the observed interaction between specific associations and executive control (EC) was robust: trait impulsivity did not diminish the prediction of alcohol use by the interaction. Trait impulsivity was not always related to alcohol use, and when it was, the predictive power disappeared after entering the interaction between behavior-specific associations and EC in one study, but not in the other. These findings are interpreted in relation to the validity of the measurements used, which leads to a more refined hypothesis. PMID:21833213

Wiers, Reinout W; Ames, Susan L; Hofmann, Wilhelm; Krank, Marvin; Stacy, Alan W

2010-01-01

98

Impulsivity, impulsive and reflective processes and the development of alcohol use and misuse in adolescents and young adults  

Directory of Open Access Journals (Sweden)

Full Text Available This paper contrasts dual-process and personality approaches in the prediction of addictive behaviors and related risk behaviors. In dual-process models, behavior is described as the joint outcome of qualitatively different “impulsive” (or associative and “reflective” processes. There are important individual differences regarding both types of processes, and the relative strength of both in a specific situation is influenced by prior behavior and state variables (e.g., fatigue, alcohol use. From this perspective, a specific behavior (e.g., alcohol misuse can be predicted by the combined indices of the behavior-related impulsive processes (e.g., associations with alcohol, and reflective processes, including the ability to refrain from a motivationally salient action. Personality approaches have reported that general traits such as impulsivity predict addictive behaviors. Here we contrast these two approaches, with supplementary analyses on four datasets. We hypothesized that trait impulsivity can predict specific risky behaviors, but that its predictive power disappears once specific behavior-related associations, indicators of executive functioning, and their interaction are entered into the equation. In all four studies the observed interaction between specific associations and Executive Control (EC was robust: trait impulsivity did not diminish the prediction of alcohol use by the interaction. Trait impulsivity was not always related to alcohol use, and when it was, the predictive power disappeared after entering the interaction between behavior-specific associations and EC in one study, but not in the other. These findings are interpreted in relation to the validity of the measurements used, which leads to a more refined hypothesis.

ReinoutWiers

2010-09-01

99

Cocaine Modulation of Frontostriatal Expression of Zif268, D2, and 5-HT2c Receptors in High and Low Impulsive Rats  

OpenAIRE

Impulsivity shares high comorbidity with substance abuse in humans, and high impulsivity (HI) in rats has been identified as a predictive factor for cocaine addiction-like behavior. Despite the evidence that high impulsivity is associated with altered function of corticostriatal networks, the specific neural substrates underlying the increased vulnerability of impulsive individuals to develop cocaine addiction remain unknown. We therefore investigated specific neural correlates of HI within t...

Besson, Morgane; Pelloux, Yann; Dilleen, Ruth; Theobald, David Eh; Lyon, Alan; Belin-rauscent, Aude; Robbins, Trevor W.; Dalley, Jeffrey W.; Everitt, Barry J.; Belin, David

2013-01-01

100

Cross-Field Electron Heat Transport in a Magnetoplasma, in the Presence of Ion Turbulence  

Science.gov (United States)

Cross-field heat transport through a cylindrical pulsed argon afterglow magnetoplasma, (B_0 = 48-300G, rm T_{e} ~ 0.5-7 eV, n_{e} ~ 10^{11} cm^{ -3}, Phi_{s } ~ 2V, radius = 5 cm), is investigated. The study of heat flow is relevant to the fields of fusion engineering and space physics. A BaO-coated dispenser cathode is used to produce a pulsed electron beam, (V_{b}=750 V, I_{b} = 1A, radius = 1.27 cm, tau_{b} = 5 - 10mus, fired 300 mus into the afterglow), propagating down the central axis of the plasma. The beam heats the background electrons within some centimeters of the beam launching point (Whe85); heat diffuses along field lines, forming a "flux tube" of hot plasma. Biased grids, (radius = 5 cm, V_{g} = -200V), are used to retard the axial heat flow through the tube. A radially inserted Langmuir probe is used to map T_{e}, n_ {e}, and Phi_{s } as a function of position and time. There profiles are used to deduce the electron cross-field thermal conductivity coefficient, kappa_| . Anomalous heat transport is found for all cases studied; kappa_| is found to be up to two orders of magnitude above classical predictions. Such transport is attributed to quasilinear effects; collisions of the background electrons with radial ion acoustic waves created indirectly by the beam, through action of the beam/plasma and oscillating two-stream instabilities (Whe85), and with azimuthal ion acoustic waves, created by the pressure-gradient instability(All74). An enhanced collision frequency leads to faster cross-field particle and heat diffusion. Measurements of wave amplitudes are presented, as are correlation measurements proving the waves are ion acoustic. Comparisons of experimental measurements with quasilinear theory predictions (Man78) are shown to be quite close.

Needelman, David Dore

101

Non-linear diffusion of charged particles in a turbulent magnetoplasma  

International Nuclear Information System (INIS)

A unified theory is presented which describes non-linear effects on relative and absolute diffusion of charged particles in a magnetoplasma, in analogy with analogous methods used for diffusion studies of pollutants in the environment. Explicit results are obtained for non-linear diffusion of test particles represented by their guiding centers in a turbulent energy spectrum in K-1 and K-3, which corresponds to recent measurements in the T.F.R. Tokamak. As expected, a BOHM scaling of the absolute diffusion coefficient is obtained for frozen turbulence. The growth of an initially small cloud of particles in an arbitrary turbulent medium corresponds to the process of relative diffusion. It is described by a generalization of the Brownian motion, including a first stage of very slow initial relative diffusion, followed by a stage of rapid expansion of the cloud up to the final stage in which particles become uncorrelated, and Brownian diffusion is reached asymptotically. The stage of exponential growth, observed in fluid turbulence corresponds to the clump effect in plasma turbulence. It is entirely due to the effect of trajectory correlations. The LJAPUNOV exponent of this exponential separation is obtained analytically. Numerical solutions of the diffusion equation are presented for the effective radius of the cloud as function of time in the case of a model spectrum of drift-wave turbulence. When compared with classical Brownian diffusion of uncorrelated particles, the effective ''diffusion coefficient'' for correlated particles is found to be reduced by orders of magnitude for rather long times. Practical implications for experimental situations are also discussed (Barium clouds released in the ionosphere, pellet injection in e.g. Tokamaks)

102

Online Impulse Buying and Product Involvement  

OpenAIRE

Do consumers behavior different on the Internet from other marketing channels? This study investigates impulse buying behaviors in both traditional store and online shopping contexts. The results show that impulsive buying tendency and involvement with clothing products is positively associated with impulse buying behavior of clothing in traditional store shopping, but not online. For computer peripherals, on the other hand, higher impulsive buying tendency and higher product involvement are ...

Tsai Chen

2008-01-01

103

Emotion Regulation and Impulsivity in Young Adults  

OpenAIRE

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 behavi...

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

2012-01-01

104

Attractivity of nonlinear impulsive delay differential equations  

Directory of Open Access Journals (Sweden)

Full Text Available The attractivity of nonlinear differential equations with time delays and impulsive effects is discussed. We obtain some criteria to determine the attracting set and attracting basin of the impulsive delay system by developing an impulsive delay differential inequality and introducing the concept of nonlinear measure. Examples and their simulations illustrate the effectiveness of the results and different asymptotical behaviors between the impulsive system and the corresponding continuous system.

Zhichun Yang

2006-01-01

105

Impulse sales cooler. Final report  

Energy Technology Data Exchange (ETDEWEB)

In the past years, the use of impulse coolers has increased considerably and it is estimated that at least 30.000 are installed in shops in Denmark. In addition, there are many small barrel-shaped can coolers. Most impulse coolers are open, which results in a large consumption of energy, and the refrigeration systems are often quite inefficient. A typical impulse cooler uses app. 5 - 8 kWh/day corresponding to a consumption of energy in the magnitude of 60 GWh/year. For several years, the Danish company Vestfrost A/S has produced an impulse sales cooler in the high-efficiency end and the energy consumption of the cooler is measured to be 4.15 kWh/day. The POS72 cooler formed the baseline of this project. At the start-up meeting in 2008, several ideas were discussed with the objective to reduce energy consumption and to use natural refrigerants. Among the ideas were better air curtains, removable lids, better condensers, use of R600a refrigeration system and better insulation. Three generations of prototypes were built and tested in a climate chamber at Danish Technological Institute and the third generation showed very good performance: the energy consumption was measured to 2.215 kWh/day, which is a 47% reduction compared to the baseline. That was achieved by: 1) Improving the cold air cycling system including the air curtain. 2) Using the natural refrigerant R600a (isobutane) and the Danfoss NLE9KTK compressor, which has better efficiency compared to the compressor in the baseline product. 3) Using a box type condenser without fins (preventing dust build-up) and with a relatively high surface area. 4) Improving the insulation value of the plastic cabinet by reducing turbulence in the air gap between the plastic walls and improving the insulation value of the EPS moulded insulation surrounding the refrigeration system at the bottom of the cooler. 5) Preventing short-circuit of warm air around the condenser. 6) The improvements are cost efficient and will not add much to the cost of the cooler. The development project has resulted in a unique impulse sales cooler using natural refrigerant and a refrigeration system, which consumes about half the amount of energy compared to the previous Vestfrost impulse cooler and less than half of the energy compared to other types of impulse sales coolers. (LN)

Pedersen, Per Henrik (DTI, Taastrup (Denmark))

2010-11-15

106

High-intensity drying processes: Impulse drying. Progress report on furnish evaluations for impulse drying commercialization demonstration  

Energy Technology Data Exchange (ETDEWEB)

Laboratory and pilot scale experiments were performed to identify potential furnishes and operating parameters for upcoming high-speed pilot scale trials and commercial demonstration of impulse drying of heavy weight grades of paper. Results indicate that hydrodynamic specific surface is highly dependent on sheet formation and prehandling. Mill refined pulp and machine paper were comparable to laboratory prepared samples in regards to permeability and impulse drying. Process variables such as platen surface coating, felt type, felt moisture, and presteaming temperature profiles were investigated. Substantial improvements in sheet smoothness were achieved.

Orloff, D.I.; Phelan, P.M.; Rudman, I.

1995-02-01

107

Full averaging of fuzzy impulsive differential inclusions  

Directory of Open Access Journals (Sweden)

Full Text Available In this paper the substantiation of the method of full averaging for fuzzy impulsive differential inclusions is studied. We extend the similar results for impulsive differential inclusions with Hukuhara derivative (Skripnik, 2007, for fuzzy impulsive differential equations (Plotnikov and Skripnik, 2009, and for fuzzy differential inclusions (Skripnik, 2009.

Natalia V. Skripnik

2010-09-01

108

Laser impulse coupling at 130 fs  

International Nuclear Information System (INIS)

We measured the momentum coupling coefficient C m and laser-generated ion drift velocity and temperature in the femtosecond (fs) region, over a laser intensity range from ablation threshold to about one hundred times threshold. Targets were several pure metals and three organic compounds. The organic compounds were exothermic polymers specifically developed for the micro-laser plasma thruster, and two of these used 'tuned absorbers' rather than carbon particles for laser absorption. The metals ranged from Li to W in atomic weight. We measured time of flight (TOF) profiles for ions. Specific impulse reached record values for this type of measurement and ablation efficiency was near 100%. These measurements extend the laser pulsewidth three orders of magnitude downward in pulsewidth relative to previous reports. Over this range, we found C m to be essentially constant. Ion velocity ranged from 60 to 180 km/s

109

Neuroanatomical and Neurochemical Basis of Impulsivity  

Directory of Open Access Journals (Sweden)

Full Text Available The term ‘impulsivity’ encompasses a multitude of behaviours that are poorly conceived, premature, inappropriate, and that frequently result in unwanted or deleterious outcomes. Impulsivity manifests as impatience carelessness, risk-taking, sensation-seeking and pleasure-seeking, an underestimated sense of harm, and extroversion. Impulsivity is a core symptom of a broad spectrum of psychiatric disorders. Through focusing on different aspects of impulsive behavior, it has proved possible to devise a variety of behavioral paradigms to measure impulsivity in both human and non-human subjects. These can be broadly divided into two categories: those measuring impulsive action or motoric impulsivity, and those measuring impulsive choice or impulsive decision-making. Impulsive action can be broadly defined as the inability to withhold from making a response. Within the framework of behavioral neuroscience and cognitive psychology, impulse control has been described as an active inhibitory mechanism which modulates the internally or externally driven pre-potent desire for primary reinforcers such as food, sex or other highly desirable rewards. This inhibitory control mechanism may provide the substrate by which rapid conditioned responses and reflexes are transiently suppressed, so that slower cognitive mechanisms can guide behavior. This process is referred to as response inhibition. Two of the most common tests used to study inhibitory processes are the go/no-go and stop-signal reaction time tasks. Impulsivity is also evident in the making of impulsive decisions or choices as well as in impulsive actions. Here, there is no “pre-potent” response that is primed and then forcibly inhibited, but a decision-making processes. Impulsive decision making or impulsive choice is defined as initiating actions without adequately considering other possible choices or consequences. Impulsive choice is typically measured in the delay discounting paradigm. In tis paradigm, the tendency to prefer small immediate rewards over larger, more delayed reinforcers is measured. ?mpulsive choice is defined by a greater tendency to value or choose smaller, more immediate reinforcers. Impulsivity is a multi-faceted behaviour. This behaviour may be studied by subdividing it into different processes neuroanatomically and neurochemically. Neuroanatomical data support the suggestion that behavioral disinhibition (impulsive action / motoric impulsivity and delay-discounting (impulsive choice / decision making differ in the degree to which various components of frontostriatal loops are implicated in their regulation. The dorsal prefrontal cortex does not appear to be involved in mediating impulsive choice, yet does have some role in regulating inhibitory processes. In contrast, there appears to be a pronounced role for the orbitofrontal cortex and basolateral amygdala in controlling impulsive choice. Other structures, however, such as the nucleus accumbens and subthalamic nucleus may be common to both circuits. From the neurochemical perspective, dopamine system and dopamine- 2 (D2 receptors in particular, seems to be closely involved in making impulsive choice. When the noradrenaline system does not function optimally, it might contribute to increased impulsivity. Serotonin might act upon prefrontal cortex to decrease impulsive choices. Interactions between the serotonin and the dopamine systems are important in the regulation of impulsive behaviour. It is possible that various receptor subtypes of the serotonin system may exert differing and even contrasting effects on impulsive behaviour. Although it is very informative to study neurotransmitter systems separately, it should be kept in mind that there are very intimate interactions between the neurotransmitter systems mentioned above. Based on the fact that impulsivity is regulated through multiple neurotransmitters and even more receptors, one may suggest that pharmacotherapy of impulsivity requires a drug acting on more than one receptor. In addition, when considering improving

Kemal Yazici

2010-08-01

110

Stroop test performance in impulsive and non impulsive patients with Parkinson’s disease  

OpenAIRE

Impulsive personalities are considered to have a general impairment in cognitive flexibility and cortical inhibition. To examine this hypothesis we used a trial by trial Stroop task in impulsive and non impulsive patients with Parkinson’s disease (PD) and recorded errors and reaction times (RT). We tested 28 impulsive PD (PD+ICB) and 24 non impulsive PD (PD-ICB) patients prior to and after dopaminergic medication. These results were compared with 24 age matched normal controls. We found an ...

Djamshidian, Atbin; O’sullivan, Sean S.; Lees, Andrew; Averbeck, Bruno B.

2011-01-01

111

Online Impulse Buying and Product Involvement  

Directory of Open Access Journals (Sweden)

Full Text Available Do consumers behavior different on the Internet from other marketing channels? This study investigates impulse buying behaviors in both traditional store and online shopping contexts. The results show that impulsive buying tendency and involvement with clothing products is positively associated with impulse buying behavior of clothing in traditional store shopping, but not online. For computer peripherals, on the other hand, higher impulsive buying tendency and higher product involvement are positively associated with higher impulse buying online, but not in-store shopping.

Tsai Chen

2008-12-01

112

FM over impulse radio UWB  

OpenAIRE

Recent regulatory action provided access to large chunks of spectrum for low spectral power density ultra-wideband communication and sensing devices, yet use of this spectrum currently lags behind expectations. The authors propose a simple migration path suitable for low-cost analog audio and video distribution. It uses FM modulation of the clock signal to an impulse radio pulse generator and a simple receiver based on a rectifier or squaring device which retrieves the FM modulated signal. Us...

Schleicher, Bernd; Ghaleb, Hatem; Trasser, Andreas; Schumacher, Hermann

2009-01-01

113

UWB impulse radio for RFID  

OpenAIRE

In recent years RFID has become more and more widespread and is being used in an ever growing number of applications. Current RFID technology does however face some difïculties in several possible new applications. A change in technology is needed and in this thesis we will examine a very promising candidate, namely Ultra wide band Impulse radio (UWB-IR). To verify the viability of this technology a test chip has been made in 90 nm CMOS process.

Moen, Ha?vard

2006-01-01

114

Nonlinear dispersion and transverse profile of intense electromagnetic waves, propagating through electron-positron-ion hot magnetoplasma  

Science.gov (United States)

Self-guided nonlinear propagation of intense circularly-polarized electromagnetic waves in a hot electron-positron-ion magnetoplasma is studied. Using a relativistic fluid model, a nonlinear equation is derived, which describes the interaction of the electromagnetic wave with the plasma in the quasi-neutral approximation. Transverse Eigen modes, the nonlinear dispersion relation and the group velocity are obtained. Results show that the transverse profile in the case of magnetized plasma with cylindrical symmetry has a radially damping oscillatory form. Effect of applying external magnetic fields, existence of the electron-positron pairs, changing the amplitude of the electromagnetic wave, and its polarization on the nonlinear dispersion relation and Eigen modes are studied.

Javan, N. Sepehri; Homami, S. H. H.

2015-02-01

115

Nonparaxial theory of laser-driven plasma waves phase velocity in partially stripped magneto-plasma channels and wakefield acceleration  

Science.gov (United States)

A nonlinear theory of nonparaxial propagation of ultraintense and ultrashort circularly polarized Gaussian laser pulses through an inhomogeneous partially stripped underdense magneto-plasma channel with a parabolic radial density profile is examined analytically and by one-dimensional particle-in-cell simulations. The direction of magnetic field is considered along the direction of propagation of the pulse. An analytical expression for the wakefield is derived. It is observed that wakefield structures depend on the applied external magnetic field and inhomogeneity of a plasma. Further, equations for the plasma waves phase velocity and the laser pulse group velocity are derived and examined numerically. It is observed that the group velocity of a laser pulse is significantly greater than the plasma waves phase velocity. These velocities depend on the applied magnetic field and the polarization state of the electric field of the laser pulse.

Sharma, B. S.; Jain, Arachna

2013-02-01

116

Prueba de impulso cefálico / Head impulse test  

Scientific Electronic Library Online (English)

Full Text Available SciELO Chile | Language: Spanish Abstract in spanish Introducción: Dentro del estudio de la función del equilibrio, la prueba de impulso cefálico representa una herramienta rápida, sencilla y de fácil interpretación, que explora la indemnidad del reflejo óculo-vestibular. Este examen ha cobrado relevancia reciente como complemento a la prueba calórica [...] en diversos contextos y no ha sido explorado en nuestro país. Objetivo: Explorar sensibilidad y especificidad de esta prueba en nuestro contexto local, junto con contribuir a la difusión de una herramienta de creciente relevancia en otoneurología. Material y método: Estudio prospectivo, ciego, de evaluación de test diagnóstico. En una muestra de pacientes consultando por vértigo agudo se realizó prueba de impulso cefálico al momento de la consulta inicial, y al momento de realizar prueba funcional de VIII par. Resultados: Se evaluaron 52 pacientes, 44% de ellos con disfunción vestibular según prueba calórica clásica como patrón de oro. La sensibilidad de la prueba de impulso cefálico fue de 47,6% y su especificidad de 83,9%, con un valor predictivo positivo y negativo de 66,7% y 70,3%. El acuerdo del examen entre dos evaluadores independientes fue alto (Kappa = 0,84). Discusiones: A pesar de una baja sensibilidad por sí sola, la prueba de impulso cuenta con una alta especificidad y un valor predictivo positivo razonable. Es además altamente reproducible, realizable en menos de un minuto y no genera náuseas u otros síntomas en el paciente. Consideramos este examen como un complemento al estudio de la función vestibular, con implicaciones prácticas en el inicio precoz de terapia y con importantes potencialidades en diversos ámbitos de la otoneurología. Abstract in english Introduction: In balance function evaluation, head impulse test is a fast, simple and easy to interpret test, which explores the vestibulo-ocular reflex. Having gained in the last decade growing importance as a complement to traditional caloric test, this test hasn't been explored in our context yet [...] . Aim: To assess sensitivity and specificity of this test in our context, along with contributing to the spread of an increasingly important tool in otoneurology Material and method: A prospective, blinded, diagnostic test assessment. In a sample of patients consulting for acute vertigo, head impulse test was performed at the time of initial consultation, and at the time of VIII nerve functional testing. Results: We evaluated 52 patients, 44% with vestibular dysfunction as shown in caloric test results as gold standard. Sensitivity of the head impulse test was 47.6%, its specificity 83.9%, with positive and negative predictive value of 66.7% and 70.3% respectively. Agreement between two independent examiners was high (Kappa = 0.84). Discussion: Despite its low sensitivity, impulse test showed a high specificity and a reasonable positive predictive value. It was also highly reproductible, and generates no nausea or other symptoms in the patient. We consider this test as a complement to vestibular function evaluation, with clinical applicationssupportingearly onset of therapy. We believe this test to withhold significant potential in various otoneurological developing applications.

Hayo A, Breinbauer K; José Luis, Anabalón B.

2011-08-01

117

A Review of Impulse Buying Behavior  

Directory of Open Access Journals (Sweden)

Full Text Available Researchers and Practitioners have been interested in the field of impulse buying for the past sixty years (Clover,1950; Stern, 1962; Rook, 1987; Peck and Childers, 2006; Chang et.al, 2011. The purpose of this paper is toprovide a detailed account of the impulse buying behavior by compiling the various research works literature inthe field of Retailing and Consumer Behavior. It gives a broad overview of the impulse buying construct and thevarious behavior related aspects. A wide range of journal databases and books were referred to review the worksof various researchers. The content analysis of the various research works led to the classification of literatureinto different factors influencing impulse buying and further development of research framework. The multipleaspects of the subject are categorized for future research works in the area of impulse buying with thesuggestions. The paper will be useful for marketing practitioners and researchers towards comprehensiveunderstanding of the consumer’s impulsiveness.  

G. Muruganantham

2013-04-01

118

Impulsivity, gambling cognitions, and the gambler's fallacy in university students.  

Science.gov (United States)

The present study explored the associations among impulsivity, gambling cognitions, and behavioral adherence to the gambler's fallacy in university students (N = 142). Both impulsivity and gambling cognitions were significant predictors of non-problem and problem gambler categories as defined the Problem Gambling Severity Index. A logistic regression analysis showed that the independent contribution of cognition was statistically significant but that the contribution of impulsivity was not. A behavioral measure of gambling was obtained by asking participants to play an online game of roulette for a maximum of 15 min. Only outside bets were permitted whereby participants were to bet on the color of the winning number. Adherence to the gambler's fallacy was indexed by the likelihood of betting on an alternation in the color of the winning number as the number of consecutive outcomes of the other color increased. Gambling cognitions and gender, but not impulsivity, were associated with adherence to the gambler's fallacy. Tracing the sources of specific influences on gambling behavior may benefit from a framework that distinguishes between "hot" (emotional) and "cold" (non-emotional) mechanisms that promote problem gambling. PMID:24293013

Marmurek, Harvey H C; Switzer, Jessica; D'Alvise, Joshua

2015-03-01

119

Plasma wave instabilities as inverse anderson localization: magnetoplasma Bernstein mode-drift wave and Bernstein mode-ion acoustic wave hybridization  

International Nuclear Information System (INIS)

Plasma wave instabilities via wave-wave coupling are argued to be a form of inverse Anderson localization in the Siegel generalized-disorder collective-boson modesoftening universality-principle (GDCBMSUP). In particular, magnetoplasma Bernstein cyclotron modedrift wave and magnetoplasma Bernstein cyclotron mode-ion acoustic wave hybridization instabilities, whether growing or decaying in amplitude, are viewed as stopping-band formation in wavevector and/or energy(frequency) in the scatterer dispersion dispersion relation with hybridization induced density of states energy(frequency) gap formation due to isotropic backscattering in the scatteree dispersion relation. This isotropic backscattering of scatteree(positive group velocity) wave by scatterer(negative group velocity) wave at an up-down crossing in plasma wave dispersion relation produces a Mott-Hubbard gap in the scatteree plasma wave density of states in which scatteree plasma wave pass-band tails exponentially decay into the scatteree stopping-band gap in space and/or time. It is seen that a magnetoplasma Bernstein cyclotron mode experiences a drift wave or an ion acoustic wave (or even a deviation of its propagation angle from normal to the applied magnetic field direction) as generalized-disorder symmetry-breaking, and is thus driven to mode-soften with negative-dispersion via hybridization with the other (scatteree) plasma wave, yielding the negative group velocity stopping band in wavevector and energy(fy stopping band in wavevector and energy(frequency)

120

Impulse control maximum principle: Theory and applications  

OpenAIRE

The contribution of this paper is threefold. First, this thesis extends the existing theory on Impulse Control by deriving the necessary optimality conditions in current value formulation and provide a transformation such that the Impulse Control Maximum Principle can be applied to problems having a fixed cost. Moreover, this thesis points out that meaningful problems do not satisfy the sufficiency conditions. Second, in this thesis the Impulse Control Maximum Principle is applied to dike hei...

Chahim, M.

2013-01-01

121

Impulsiveness without discounting: the ecological rationality hypothesis.  

OpenAIRE

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 discou...

Stephens, David W.; Kerr, Benjamin; Ferna?ndez-juricic, Esteban

2004-01-01

122

Non-expanding impulsive gravitational waves  

OpenAIRE

We investigate a class of impulsive gravitational waves which propagate either in Minkowski or in the (anti-)de Sitter background. These waves are constructed as impulsive members of the Kundt class $P(\\Lambda)$ of non-twisting, non-expanding type N solutions of vacuum Einstein equations with a cosmological constant $\\Lambda$. We show that the only non-trivial waves of this type in Minkowski spacetime are impulsive pp-waves. For $\\Lambda\

Podolsky, J.

1998-01-01

123

Response patterns of children with learning disabilities: is impulsivity a stable response style?  

Science.gov (United States)

A correlational analysis was conducted to assess the relationship among various assessment instruments, including Kagan, Rosman, Day, Albert, and Phillips's (1964) Matching Familiar Figures Test (MFFT), and actual classroom performance vis-à-vis impulsive responding. Subjects were 22 children (16 male, 6 female), ages 5 to 11 years, enrolled in an academic remediation program. The results do not support a relationship between impulsivity, as measured by the MFFT, and academic progress in a classroom setting. Implications for task-specific measures of impulsivity and remediation are discussed. PMID:1875160

Harrison, K A; Romanczyk, R G

1991-04-01

124

Simplified calculation of detonation induced impulse  

International Nuclear Information System (INIS)

Simplified methods of estimating the impulse generated by detonations propagating through gaseous fuel-oxidizer mixtures are developed. First the ground and dynamic impulse are defined. Self similar solutions are used to derive expressions for the ground and dynamic impulse of detonations confined clouds with plane, cylindrical, and spherical symmetry in terms of universal impulse functions which are independent of the detonation properties. A similar analysis is developed for clouds bounded by an inert gas which results in side relief. In this case the results are found to be in good agreement with experiment and with hydrocode calculations

125

Impulsive synchronization of networked nonlinear dynamical systems  

International Nuclear Information System (INIS)

In this Letter, we investigate the problem of impulsive synchronization of networked multi-agent systems, where each agent can be modeled as an identical nonlinear dynamical system. Firstly, an impulsive control protocol is designed for network with fixed topology based on the local information of agents. Then sufficient conditions are given to guarantee the synchronization of the networked nonlinear dynamical system by using algebraic graph theory and impulsive control theory. Furthermore, how to select the discrete instants and impulsive constants is discussed. The case that the topologies of the networks are switching is also considered. Numerical simulations show the effectiveness of our theoretical results.

126

Test-retest reliability of behavioral measures of impulsive choice, impulsive action, and inattention  

OpenAIRE

Behavioral measures of impulsivity are widely used in substance abuse research, yet relatively little attention has been devoted to establishing their psychometric properties, especially their reliability over repeated administration. The current study examined the test-retest reliability of a battery of standardized behavioral impulsivity tasks, including measures of impulsive choice (delay discounting, probability discounting, and the Balloon Analogue Risk Task), impulsive action (the stop ...

Weafer, Jessica; Baggott, Matthew J.; Wit, Harriet

2013-01-01

127

Saturation of Richtmyer's impulsive model  

International Nuclear Information System (INIS)

In this Brief Communication, we use results from two-dimensional simulations to calculate for what product of perturbation wave number (k) and initial amplitude (a0) the Richtmyer impulsive model will fail in its prediction of shock wave driven instability growth as a function of initial shock Mach number. For ''large'' ka0, we suggest a formula which bounds the maximum value of the ratio of the amplitude growth rate over the interface speed by one minus the ratio of the interface speed and the transmitted shock speed. (c) 2000 American Institute of Physics

128

Acoustic radiation force impulse imaging for differentiation of thyroid nodules  

OpenAIRE

Background: Acoustic Radiation Force Impulse (ARFI)-Imaging is an ultrasound-based elastography method enabling quantitative measurement of tissue stiffness. The aim of the present study was to evaluate sensitivity and specificity of ARFIimaging for differentiation of thyroid nodules and to compare it to the well evaluated qualitative real-time elastography (RTE). Methods: ARFI-imaging involves the mechanical excitation of tissue using acoustic pulses to generate localized disp...

Bojunga, Joerg; Dauth, Nina; Berner, Christian; Meyer, Gesine; Holzer, Katharina; Voelkl, Lisa; Herrmann, Eva; Schroeter, Hartmut; Zeuzem, Stefan; Friedrich-rust, Mireen

2012-01-01

129

Impulse responses in bacterial chemotaxis.  

Science.gov (United States)

The chemotactic behavior of Escherichia coli has been studied by exposing cells tethered by a single flagellum to pulses of chemicals delivered iontophoretically. Normally, wild-type cells spin alternately clockwise and counterclockwise, changing their direction on the average approximately once per second. When cells were exposed to a very brief diffusive wave of attractant, the probability of spinning counterclockwise quickly peaked, then fell below the prestimulus value, returning to baseline within a few seconds; repellent responses were similar but inverted. The width of the response indicates that cells integrate sensory inputs over a period of seconds, while the biphasic character implies that they also take time derivatives of these inputs. The sensory system is maximally tuned to concentration changes that occur over a span of approximately 2 sec, an interval over which changes normally occur when cells swim in spatial gradients; it is optimized to extract information from signals subject to statistical fluctuation. Impulse responses of cells defective in methylation were similar to those of wild-type cells, but did not fall as far below the baseline, indicating a partial defect in adaptation. Impulse responses of cheZ mutants were aberrant, indicating a serious defect in excitation. PMID:6760985

Block, S M; Segall, J E; Berg, H C

1982-11-01

130

Embedded diagnosis for pressure transmitters. Automatic detection of the impulse lines plugging in differential pressure transmitters  

Energy Technology Data Exchange (ETDEWEB)

The paper shows the successful implementation of the plugged-impulse-lines diagnostic function in a differential pressure transmitter. The algorithm is self-adaptive to the specific process conditions at the time of installation and proved to be applicable for both liquids and gases. Special care was taken for avoiding false alarms and having at the same time good diagnosis effectiveness. Several field tests proved the usability of the plugged-impulse-line detection function in industrial applications. (orig.)

Andenna, A. [ABB Schweiz AG, Baden-Daettwil (Switzerland); Eifel, D. [ABB AG, Mannheim (Germany); Invernizzi, G. [ABB S.p.A., Lenno (Italy)

2007-07-01

131

Epidemiologic and clinical updates on impulse control disorders: a critical review  

OpenAIRE

The article reviews the current knowledge about the impulse control disorders (ICDs) with specific emphasis on epidemiological and pharmacological advances. In addition to the traditional ICDs present in the DSM-IV—pathological gambling, trichotillomania, kleptomania, pyromania and intermittent explosive disorder—a brief description of the new proposed ICDs—compulsive–impulsive (C–I) Internet usage disorder, C–I sexual behaviors, C–I skin picking and C–I shopping—is provided...

Dell’osso, Bernardo; Altamura, A. Carlo; Allen, Andrea; Marazziti, Donatella; Hollander, Eric

2006-01-01

132

Impulsivity, impulsive and reflective processes and the development of alcohol use and misuse in adolescents and young adults  

OpenAIRE

This paper contrasts dual-process and personality approaches in the prediction of addictive behaviors and related risk behaviors. In dual-process models, behavior is described as the joint outcome of qualitatively different “impulsive” (or associative) and “reflective” processes. There are important individual differences regarding both types of processes, and the relative strength of both in a specific situation is influenced by prior behavior and state variables (e.g...

ReinoutWiers; WilhelmHofmann; MarvinKrank; AlanStacy

2010-01-01

133

Impulsivity, School Context, and School Misconduct  

Science.gov (United States)

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…

Vogel, Matt; Barton, Michael S.

2013-01-01

134

Impulsive stabilization and impulsive synchronization of discrete-time delayed neural networks.  

Science.gov (United States)

This paper investigates the problems of impulsive stabilization and impulsive synchronization of discrete-time delayed neural networks (DDNNs). Two types of DDNNs with stabilizing impulses are studied. By introducing the time-varying Lyapunov functional to capture the dynamical characteristics of discrete-time impulsive delayed neural networks (DIDNNs) and by using a convex combination technique, new exponential stability criteria are derived in terms of linear matrix inequalities. The stability criteria for DIDNNs are independent of the size of time delay but rely on the lengths of impulsive intervals. With the newly obtained stability results, sufficient conditions on the existence of linear-state feedback impulsive controllers are derived. Moreover, a novel impulsive synchronization scheme for two identical DDNNs is proposed. The novel impulsive synchronization scheme allows synchronizing two identical DDNNs with unknown delays. Simulation results are given to validate the effectiveness of the proposed criteria of impulsive stabilization and impulsive synchronization of DDNNs. Finally, an application of the obtained impulsive synchronization result for two identical chaotic DDNNs to a secure communication scheme is presented. PMID:25794379

Chen, Wu-Hua; Lu, Xiaomei; Zheng, Wei Xing

2015-04-01

135

Self-focusing of a Hermite-cosh Gaussian laser beam in a magnetoplasma with ramp density profile  

Energy Technology Data Exchange (ETDEWEB)

The early and strong self-focusing of a Hermite-cosh-Gaussian laser beam in magnetoplasma in the presence of density ramp has been observed. Focusing and de-focusing nature of the Hermite-cosh-Gaussian laser beam with decentered parameter and magnetic field has been studied, and strong self-focusing is reported. It is investigated that decentered parameter 'b' plays a significant role for the self-focusing of the laser beam and is very sensitive as in case of extraordinary mode. For mode indices, m = 0, 1, 2,?and?b = 4.00, 3.14,?and?2.05, strong self-focusing is observed. Similarly in case of ordinary mode, for m = 0, 1, 2?and?b = 4.00, 3.14, 2.049, respectively, strong self-focusing is reported. Further, it is seen that extraordinary mode is more prominent toward self-focusing rather than ordinary mode of propagation. For mode indices m = 0, 1,?and?2, diffraction term becomes more dominant over nonlinear term for decentered parameter b=0. For selective higher values of decentered parameter in case of mode indices m=0, 1,?and?2, self-focusing effect becomes strong for extraordinary mode. Also increase in the value of magnetic field enhances the self-focusing ability of the laser beam, which is very useful in the applications like the generation of inertial fusion energy driven by lasers, laser driven accelerators, and x-ray lasers.

Nanda, Vikas; Kant, Niti; Wani, Manzoor Ahmad [Department of Physics, Lovely Professional University, Phagwara 144411, Punjab (India)

2013-11-15

136

Self-focusing of a Hermite-cosh Gaussian laser beam in a magnetoplasma with ramp density profile  

International Nuclear Information System (INIS)

The early and strong self-focusing of a Hermite-cosh-Gaussian laser beam in magnetoplasma in the presence of density ramp has been observed. Focusing and de-focusing nature of the Hermite-cosh-Gaussian laser beam with decentered parameter and magnetic field has been studied, and strong self-focusing is reported. It is investigated that decentered parameter 'b' plays a significant role for the self-focusing of the laser beam and is very sensitive as in case of extraordinary mode. For mode indices, m = 0, 1, 2,?and?b = 4.00, 3.14,?and?2.05, strong self-focusing is observed. Similarly in case of ordinary mode, for m = 0, 1, 2?and?b = 4.00, 3.14, 2.049, respectively, strong self-focusing is reported. Further, it is seen that extraordinary mode is more prominent toward self-focusing rather than ordinary mode of propagation. For mode indices m = 0, 1,?and?2, diffraction term becomes more dominant over nonlinear term for decentered parameter b=0. For selective higher values of decentered parameter in case of mode indices m=0, 1,?and?2, self-focusing effect becomes strong for extraordinary mode. Also increase in the value of magnetic field enhances the self-focusing ability of the laser beam, which is very useful in the applications like the generation of inertial fusion energy driven by lasers, laser driven accelerators, and x-ray lasers

137

Self-confined plasma in a magneto-plasma compressor and the influence of an externally imposed magnetic field  

Science.gov (United States)

The spatial profile of a magnetically self-confined plasma formed by a magneto-plasma compressor is measured in radial and axial direction with an array of Faraday cups, and radiation with a wavelength as short as extreme ultraviolet is detected. A Gaussian distribution approximates the radial profile of the ion current density. Along the axis, the ion current density remains approximately constant up to 2.25 inner anode radii from the electrodes end, before diverging. The plasma stream is further compressed by the addition of an external magnetic field. The external magnetic field is measured and is close to the self-induced magnetic field. The measurements of the profile show an increase in the ion current density after the inlet into the external magnetic field. The ion current density at 3.25 inner anode radii from the end of the electrodes doubles, and the width of the plasma stream decreases. Estimations show that the increase of the ion current density is also due to an increase of around 25% of the mean ion charge, hence to a temperature increase of around 50% enhancing photon emission at shorter wavelength. A design guideline is presented to dimensionalize the amplitude of the external magnetic field depending on the wanted temperature increase in the plasma stream.

Giovannini, A. Z.; Barendregt, I.; Haslinde, T.; Hubbs, C.; Abhari, R. S.

2015-04-01

138

Development and implementation of a new ultrafast imaging diagnostic for laboratory magnetoplasma: application in the plasma radial transport characterization  

International Nuclear Information System (INIS)

Non intrusive diagnostics have been developed in order to increase the precision in the data obtained from plasmas in a turbulent state. This thesis was carried on the development and the implementation of a new diagnostic for laboratory plasmas, i.e. an ultra-fast imaging system recording the spontaneous light emission, applied in turbulent plasmas of a magnetoplasma. The low resolution camera is composed of an array of photodetectors, their sensibility is centered on the main wavelength of the studied plasmas. Moreover, records can be longer than fifty milliseconds, even with a 100.000 frames per second recording frequency. This camera allows a precise study of both the spatial evolution of a phenomena and a statistical analysis of the recorded turbulent signal. Our prototype has been used to record different instable regimes of the laboratory magnetized plasma device. The main goal of this thesis was on the development and on the validation of this new diagnostic. Further studies will be devoted to the identification of the instabilities and underlying mechanisms. (author)

139

Inductance and near fields of a loop antenna in a cold magnetoplasma in the whistler frequency band  

Science.gov (United States)

The influence of a magnetoplasma on the inductance of a circular loop antenna oriented perpendicular to the ambient static magnetic field and operated in the whistler frequency band is studied. Based on a strict electrodynamic approach, the analytical treatment of the antenna reactance is performed for a uniform rf current distribution along the antenna wire. Calculations are made for plasma parameters and operating frequencies typical for active ionospheric experiments and laboratory rf (helicon) sources of dense magnetized plasmas. It is shown that the plasma influence on the inductance of the loop antenna remains relatively weak, even for antennas with dimensions close to half of the longitudinal whistler wavelength, when the rf field distribution in the antenna near zone is strongly different from that in vacuum. The theoretical predictions are confirmed by measurements performed on the large KROT plasma device. The results obtained are of crucial importance for the preparation of active ionospheric experiments and for the matching of loop antennas used in laboratory rf sources of dense magnetized plasmas.

Gushchin, M. E.; Zaboronkova, T. M.; Krafft, C.; Korobkov, S. V.; Kostrov, A. V.

2012-09-01

140

Inductance and near fields of a loop antenna in a cold magnetoplasma in the whistler frequency band  

International Nuclear Information System (INIS)

The influence of a magnetoplasma on the inductance of a circular loop antenna oriented perpendicular to the ambient static magnetic field and operated in the whistler frequency band is studied. Based on a strict electrodynamic approach, the analytical treatment of the antenna reactance is performed for a uniform rf current distribution along the antenna wire. Calculations are made for plasma parameters and operating frequencies typical for active ionospheric experiments and laboratory rf (helicon) sources of dense magnetized plasmas. It is shown that the plasma influence on the inductance of the loop antenna remains relatively weak, even for antennas with dimensions close to half of the longitudinal whistler wavelength, when the rf field distribution in the antenna near zone is strongly different from that in vacuum. The theoretical predictions are confirmed by measurements performed on the large KROT plasma device. The results obtained are of crucial importance for the preparation of active ionospheric experiments and for the matching of loop antennas used in laboratory rf sources of dense magnetized plasmas.

141

Inductance and near fields of a loop antenna in a cold magnetoplasma in the whistler frequency band  

Energy Technology Data Exchange (ETDEWEB)

The influence of a magnetoplasma on the inductance of a circular loop antenna oriented perpendicular to the ambient static magnetic field and operated in the whistler frequency band is studied. Based on a strict electrodynamic approach, the analytical treatment of the antenna reactance is performed for a uniform rf current distribution along the antenna wire. Calculations are made for plasma parameters and operating frequencies typical for active ionospheric experiments and laboratory rf (helicon) sources of dense magnetized plasmas. It is shown that the plasma influence on the inductance of the loop antenna remains relatively weak, even for antennas with dimensions close to half of the longitudinal whistler wavelength, when the rf field distribution in the antenna near zone is strongly different from that in vacuum. The theoretical predictions are confirmed by measurements performed on the large KROT plasma device. The results obtained are of crucial importance for the preparation of active ionospheric experiments and for the matching of loop antennas used in laboratory rf sources of dense magnetized plasmas.

Gushchin, M. E.; Korobkov, S. V.; Kostrov, A. V. [Institute of Applied Physics, 603950 Nizhny Novgorod (Russian Federation); Zaboronkova, T. M. [Department of Applied Physics, Technical University of Nizhny Novgorod, 603950 Nizhny Novgorod (Russian Federation); Krafft, C. [Laboratoire de Physique des Plasmas, Ecole Polytechnique, 91128 Palaiseau Cedex, Univ. Paris Sud, 91405 Orsay Cedex (France)

2012-09-15

142

Identification of Experimental Unsteady Aerodynamic Impulse Responses  

Science.gov (United States)

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.

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

2003-01-01

143

Stability analysis of impulsive functional differential equations  

CERN Document Server

This book is devoted to impulsive functional differential equations which are a natural generalization of impulsive ordinary differential equations (without delay) and of functional differential equations (without impulses). At the present time the qualitative theory of such equationsis under rapid development. After a presentation of the fundamental theory of existence, uniqueness and continuability of solutions, a systematic development of stability theory for that class of problems is given which makes the book unique. It addresses to a wide audience such as mathematicians, applied research

Stamova, Ivanka

2009-01-01

144

Basic observational characteristics of impulsive SXR brightenings  

Science.gov (United States)

25 flares showing impulsive SXR brightenings have been investigated. The Yohkoh/SXT images have been used. The individual regions of the SXR response for each flare have been carefully localized. Some observational characteristics of them have been obtained. The results are presented in the form of histograms. For more comprehensive analysis HXR data from the Yohkoh/HXT has been incorporated. For several cases the velocity of plasma motions due to the chromospheric evaporation has been estimated directly from the SXR images. The obtained results will help to distinguish impulsive SXR brightenings from other effects and will be useful for theoretical modeling of the flare impulsive phase.

Tomczak, M.; Mrozek, T.

145

Impulse in a Double Ball Bounce  

OpenAIRE

A steel ball was dropped onto a handball which was resting on top of a horizontal Vernier force-plate. The relationship between the impact momentum of the steel ball and the impulse on the force-plate was investigated. The measured impulse was found to be proportional to the impact momentum of the falling ball, with the impulse being 2.3 times greater than the momentum. The impact of the metal ball caused the handball to compress and then bounce up following the steel ball’s bounce. This co...

Nielsen, Daniel Y.

2010-01-01

146

Pathological gambling: an impulse control disorder? Measurement of impulsivity using neurocognitive tests.  

Science.gov (United States)

Pathological gambling is classified in the DSM-IV-TR (Diagnostic and Statistical Manual of Mental Disorders) and in the ICD-10 (International Classification of Disease) as an impulse control disorder. The association between impulsivity and pathological gambling remains a matter of debate: some researchers find high levels of impulsivity within pathological gamblers, others report no difference compared to controls, and yet others even suggest that it is lower. In this review we examine the relationship between pathological gambling and impulsivity assessed by various neurocognitive tests. These tests--the Stroop task, the Stop Signal Task, the Matching Familiar Figures Task, the Iowa Gambling Task, the Wisconsin Card Sorting Test, the Tower of London test, and the Continuous Performance Test--demonstrated less impulsivity in gambling behavior. The differences in performance between pathological gamblers and healthy controls on the neurocognitive tasks could be due to addictive behavior features rather than impulsive behavior. PMID:20803888

Dannon, Pinhas N; Shoenfeld, Netta; Rosenberg, Oded; Kertzman, Semion; Kotler, Moshe

2010-04-01

147

Obtaining Binaural Room Impulse Responses from B-Format Impulse Responses  

OpenAIRE

Given a set of head related transfer functions (HRTFs) and a room impulse response measured with a Soundfield microphone, the proposed technique computes binaural room impulse responses (BRIRs) which are similar to binaural room impulse responses that would be measured if in place of the Soundfield microphone, the dummy head used for the HRTF set was directly recording the BRIRs. The proposed technique enables that from a set of HRTFs corresponding BRIRs for different rooms are ob...

Menzer, Fritz; Faller, Christof

2008-01-01

148

Antipsychotics in the treatment of impulsivity in personality disorders and impulse control disorders  

OpenAIRE

In the last years, second generation antipsychotics have shown to be useful in the treatment of disorders with predominant impulse dyscontrol symptoms, in particular borderline personality disorders (BPD) and impulse control disorders (ICDs). The present review aims to provide a comprehensive examination of data from randomized controlled trials (RCTs), open label studies, and case reports concerning efficacy and safety of atypical antipsychotics in treating symptoms of impulsivity in BPD ...

Bogetto, Filippo; Brignolo, Elena; Bozzatello, Paola; Bellino, Silvio

2013-01-01

149

Stochastic impulsive control for the stabilization of Lorenz system  

International Nuclear Information System (INIS)

This paper derives some sufficient conditions for the stabilization of Lorenz system with stochastic impulsive control. The estimate of the upper bound of impulse interval for asymptotically stable control is obtained. Some differences between the system with stochastic impulsive control and with deterministic impulsive control are presented. Computer simulation is given to show the effectiveness of the proposed method. (general)

150

Adolescent impulsivity phenotypes characterized by distinct brain networks.  

Science.gov (United States)

The impulsive behavior that is often characteristic of adolescence may reflect underlying neurodevelopmental processes. Moreover, impulsivity is a multi-dimensional construct, and it is plausible that distinct brain networks contribute to its different cognitive, clinical and behavioral aspects. As these networks have not yet been described, we identified distinct cortical and subcortical networks underlying successful inhibitions and inhibition failures in a large sample (n = 1,896) of 14-year-old adolescents. Different networks were associated with drug use (n = 1,593) and attention-deficit hyperactivity disorder symptoms (n = 342). Hypofunctioning of a specific orbitofrontal cortical network was associated with likelihood of initiating drug use in early adolescence. Right inferior frontal activity was related to the speed of the inhibition process (n = 826) and use of illegal substances and associated with genetic variation in a norepinephrine transporter gene (n = 819). Our results indicate that both neural endophenotypes and genetic variation give rise to the various manifestations of impulsive behavior. PMID:22544311

Whelan, Robert; Conrod, Patricia J; Poline, Jean-Baptiste; Lourdusamy, Anbarasu; Banaschewski, Tobias; Barker, Gareth J; Bellgrove, Mark A; Büchel, Christian; Byrne, Mark; Cummins, Tarrant D R; Fauth-Bühler, Mira; Flor, Herta; Gallinat, Jürgen; Heinz, Andreas; Ittermann, Bernd; Mann, Karl; Martinot, Jean-Luc; Lalor, Edmund C; Lathrop, Mark; Loth, Eva; Nees, Frauke; Paus, Tomas; Rietschel, Marcella; Smolka, Michael N; Spanagel, Rainer; Stephens, David N; Struve, Maren; Thyreau, Benjamin; Vollstaedt-Klein, Sabine; Robbins, Trevor W; Schumann, Gunter; Garavan, Hugh

2012-06-01

151

Synchronization of impulsively coupled complex networks  

International Nuclear Information System (INIS)

We investigate the synchronization of complex networks, which are impulsively coupled only at discrete instants. Based on the comparison theory of impulsive differential systems, a distributed impulsive control scheme is proposed for complex dynamical networks to achieve synchronization. The proposed scheme not only takes into account the influence of all nodes to network synchronization, which depends on the weight of each node in the network, but also provides us with a flexible method to select the synchronized state of the network. In addition, it is unnecessary for the impulsive coupling matrix to be symmetrical. Finally, the proposed control scheme is applied to a chaotic Lorenz network and Chua's circuit network. Numerical simulations are used to illustrate the validity of this control scheme. (general)

152

Gasdynamics of impulsive heated solar plasma  

International Nuclear Information System (INIS)

Numerical solutions for the problem of hydrodynamic response of the inhomogeneous (exponential) atmosphere on impulsive heating by energetic electrons or by very high-temperature thermal fluxes are discussed. (Auth.)

153

Extending the impulse response in order to reduce errors due to impulse noise and signal fading  

Science.gov (United States)

A finite impulse response (FIR) digital smearing filter was designed to produce maximum intersymbol interference and maximum extension of the impulse response of the signal in a noiseless binary channel. A matched FIR desmearing filter at the receiver then reduced the intersymbol interference to zero. Signal fades were simulated by means of 100 percent signal blockage in the channel. Smearing and desmearing filters of length 256, 512, and 1024 were used for these simulations. Results indicate that impulse response extension by means of bit smearing appears to be a useful technique for correcting errors due to impulse noise or signal fading in a binary channel.

Webb, Joseph A.; Rolls, Andrew J.; Sirisena, H. R.

1988-01-01

154

Impulsive frotteurism: a case report.  

Science.gov (United States)

Frotteurism is a perverted sexual behaviour wherein the person tends to rub or bring about physical contact between his genitals and an unrelated female or male to derive sexual pleasure. Moreover, frotteurism is a common phenomenon among the general population which usually goes unnoticed or overlooked. Nevertheless, public frottage has legal implications in almost all countries over the world. But, when frotteurism manifests on the backdrop of psychiatric illness or as a developmental abnormality then it is worth discussing what the legal liability would be. The present case report is based on hypersexual frotteuristic behaviour manifested on the background of a concealed psychiatric illness, featuring depression and obsessive compulsive disease. The hypersexual behaviour manifested in the form of masturbation with features of frotteurism and subsequent development of depression. Nevertheless, compulsive manifestation of frotteuristic behaviour and subsequent development of morbid depression is rare. This paper describes a 12-year-old boy having unrestrained impulsive frotteurism with his peers, school mates and with his younger brother. He was conscious of the fact and feeling guilty of what he was doing but unable to restrain himself. It was followed by the development of symptoms of depression which was treated with Sertraline. Concurrent psychiatric counseling and rehabilitation measures were taken too. There was complete remission of the symptoms 6 months after the onset of treatment and without relapse thereafter. The paper discusses the differential diagnosis and management of hypersexual behaviour. PMID:23929674

Patra, Ambika Prasad; Bharadwaj, Balaji; Shaha, Kusa Kumar; Das, Siddhartha; Rayamane, Anand P; Tripathi, Chandra Sekhara

2013-10-01

155

Leupeptin reduces impulse noise induced hearing loss  

OpenAIRE

Abstract Background Exposure to continuous and impulse noise can induce a hearing loss. Leupeptin is an inhibitor of the calpains, a family of calcium-activated proteases which promote cell death. The objective of this study is to assess whether Leupeptin could reduce the hearing loss resulting from rifle impulse noise. Methods A polyethelene tube was implanted into middle ear cavities of eight fat sand rats (16 ears). Following determination of auditory nerve brainstem evoked response (ABR) ...

Gavriel Haim; Shulman Abraham; Stracher Alfred; Sohmer Haim

2011-01-01

156

Impulse approximation in proton-hydrogen collisions  

International Nuclear Information System (INIS)

Analytic expressions for 1s-nlm differential-capture cross sections in proton-hydrogen collisions are derived. We employ the partially peaked impulse approximation and retain terms up to first order in an expansion of the Fourier transform of the potential. The exact impulse approximation is also computed using numerical integration of a three-dimensional integral. The exact and analytic calculations are compared with each other and with experiment

157

Active noise cancellation algorithms for impulsive noise  

OpenAIRE

Impulsive noise is an important challenge for the practical implementation of active noise control (ANC) systems. The advantages and disadvantages of popular filtered-X least mean square (FXLMS) ANC algorithm and nonlinear filtered-X least mean M-estimate (FXLMM) algorithm are discussed in this paper. A new modified FXLMM algorithm is also proposed to achieve better performance in controlling impulsive noise. Computer simulations and experiments are carried out for all three algorithms and th...

Li, Peng; Yu, Xun

2012-01-01

158

Adaptive Equalisation for Impulsive Noise Environments  

OpenAIRE

This thesis addresses the problem of adaptive channel equalisation in environments where the interfering noise exhibits non–Gaussian behaviour due to impulsive phenomena. The family of alpha-stable distributions has proved to be a suitable and flexible tool for the modelling of signals with impulsive nature. However,non–Gaussian alpha–stable signals have infinite variance, and signal processing techniques based on second order moments are meaningless in such environments. In or...

Georgiadis, Apostolos T.

2001-01-01

159

Intertrial interval duration and impulsive choice.  

Science.gov (United States)

Discrete-trial intertemporal choice procedures assess impulsive choice or preference for a smaller, immediate reinforcer over a larger, delayed one. The effect of the delay associated with the larger reinforcer has been the focus of much research. It, however, is not the only delay in the context of discrete-trial procedures. Often separating each choice trial is an intertrial interval (ITI) that maintains equal trial spacing of the two alternatives. The removal of this ITI has been shown to increase impulsive choice, perhaps because choosing the small alternative results in another choice trial immediately following reinforcer delivery. Impulsive choice has not been affected when the ITI duration is manipulated in conditions that equate the trial presentation rate across the two alternatives. These null results could have been due to floor effects and/or an inadequate range of ITI durations. To address these possibilities, three experiments were conducted to determine how changes in ITI duration affected impulsive choice in rats and pigeons. All three experiments found that preference for the large delayed alternative decreased (i.e., impulsive choice increased) when the ITI was shortened. Satiation was not a likely explanation since preference for the large alternative at the 0-s delay was not affected by ITI duration. Trial spacing, like other temporal properties of choice situations, is an important variable underlying the occurrence of impulsive choice. PMID:25533662

Smethells, John R; Reilly, Mark P

2015-01-01

160

Anger and Impulsivity in Adolescents Attempting Suicide  

Directory of Open Access Journals (Sweden)

Full Text Available Objective: We aimed to evaluate anger and impulsivity in adolescent suicide attempters between the ages of 12 and 18, compared with control group; investigate the relation between hostility, impulsivity and suicide intent.Patients and Methods: Thirty-six adolescent patients between the ages of 12 and 18 referred to the Marmara University Hospital, Child and Adolescent Psychiatry Policlinic because of attempted suicide between June 2009 and May 2010, were included in the study. Thirty-four healthy subjects were selected as control group. Clinical assessment of participants was made with the Kiddie Schedule for Affective Disorders and Schizophrenia Present and Life Time Version. Adolescents were also evaluated with the Spielberg State Trait Anger Expression Inventory and Barratt's Impulsivity Scale. The seriousness of attempted suicide in adolescents was determined with the Suicide Intent Scale.Results: Average total and subscores (except anger control subscore of anger and impulsivity scales were found higher in adolescents attempting suicide than in control group (p0.05.Conclusion: Anger and impulsivity merit attention in adolescent attempted suicides. Additionally, our results reinforce the need for further studies investigating the relation between personality traits, psychiatric, familial and social factors for better understanding of the effect of anger and impulsivity in adolescent suicide behavior. (Marmara Medical Journal 2012;25:148-52

Elif AKIN

2012-01-01

161

On the impulse response of monopulse radars  

Science.gov (United States)

The purpose of this study was to develop an analytical model to determine the response of an amplitude-amplitude monopulse radar to an impulsive input signal. This study was sponsored by the Air Force Electronic Warfare Center at Kelly AFB and represents a first step for determining if impulsive jamming has any merit against monopulse radar systems. From a literature review, it was determined that the receiver components most affected by an impulsive signal were filters in the receiver channel. Inverse Laplace transform techniques were used to determine the impulse response of a three-pole and a five-pole filter. A model of a logarithmic amplifier was also used. A FORTRAN computer program was written to simulate imbalances between the receiving channels of the radar. The results of the analyses showed that an impulsive signal would not cause a substantial tracking error until four to six seconds after the pulse arrive at the input of the filter, which is well out of the range gate. This signal may produce angle errors in the angle circuits of the radar without being detected by the range circuitry or the operator. It is recommended that experimental results using an impulsive electronic countermeasures signal against a monopulse radar be obtained.

Tackett, Dennis L.

1988-12-01

162

Reliable impulsive synchronization for a class of nonlinear chaotic systems  

International Nuclear Information System (INIS)

The problem of reliable impulsive synchronization for a class of nonlinear chaotic systems has been investigated in this paper. Firstly a reliable impulsive controller is designed by using the impulsive control theory. Then by the uniform asymptotic stability criteria of systems with impulsive effects, some sufficient conditions for reliable impulsive synchronization between the drive system and the response system are obtained. Numerical simulations are given to show the effectiveness of the proposed method. (general)

163

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

Science.gov (United States)

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. PMID:25698738

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

2015-02-18

164

Plasma properties in high power impulse magnetron sputtering  

OpenAIRE

The work presented in this thesis involves experimental and theoretical studies related to plasma properties in high power impulse magnetron sputtering (HiPIMS), and more specifically plasma transport. HiPIMS is an ionized PVD method based on conventional direct current magnetron sputtering (dcMS). In dcMS very little of the sputtered material is ionized since the plasma power density is not high enough. This is not the case for HiPIMS, where a substantial part is ionized, and thus presents m...

Lundin, Daniel

2008-01-01

165

Effects of acoustic impulses on hearing  

Science.gov (United States)

It is well known that acoustic impulses are especially dangerous to the ear. In order to understand the damaging mechanisms involved, cases of acute acoustic trauma in man were systematically collected and documented for many years. When possible, the damaging impulses were recreated and measured, to correlate the impulses with the auditory damage they caused. Detailed pure-tone audiometry up to 16 kHz was used to determine the effects on hearing. Together with epidemiological studies on various occupations, three different damaging mechanisms can be discerned. Relatively long and massive impulses (some explosions, some airbags) often lead to damage at low frequencies, from about 0.5 to 1.5 kHz. The typical notch at about 4 to 6 kHz typically is the result of strong peaks, lasting several milliseconds, or longer. There is another notch at 12 to 14 kHz, characteristic of very short, needle-like impulses that are caused by many hand weapons, toy pistols, and firecrackers. Probable mechanisms are discussed.

Fleischer, Gerald; Müller, Reinhard; Heppelmann, Guido; Bache, Thomas

2002-05-01

166

Micropower impulse radar technology and applications  

Energy Technology Data Exchange (ETDEWEB)

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.

Mast, J., LLNL

1998-04-15

167

Generalized impulse approximation for relativistic proton scattering  

International Nuclear Information System (INIS)

A complete set of Lorentz invariant nucleon-nucleon amplitudes, based on a meson-exchange model and on-mass-shell kinematics, is used to construct the impulse approximation optical potential for use in the Dirac equation. Relativistic nuclear densities are also used in the construction. No free parameters enter. The analysis provides a dynamical basis for the virtual pair couplings which are implicit in the Dirac equation for proton-nucleus scattering. A momentum space potential and a localized potential suitable for coordinate space analysis are developed. Initial numerical calculations are presented for proton scattering by /sup 40/Ca at 200, 500, and 800 MeV. The generalized impulse approximation provides a successful description of the elastic scattering data for these cases. Low energy results are improved substantially in comparison with the original form of Dirac impulse approximation based on using five Fermi amplitudes to represent nucleon-nucleon scattering

168

Underground scanning with an impulse radar  

International Nuclear Information System (INIS)

Impulse radar is being evaluated for possible applications at the Waste Isolation Pilot Project (WIPP) in southeastern New Mexico. Potential applications are (1) scanning salt to identify inclusions, structural discontinuities, and other anomalies before excavation; and (2) verifying the locations of stored radioactive-waste canisters. Four underground experiments were run. The extent and shape of dome-salt pillars and a langbeinite pillar were measured with the radar. Metal targets that simulated waste canisters were located to within a few centimetres after they had been buried for 18 months. If the material being scanned contains clay seams and other conductive inclusions, penetration by radar is limited. It is anticipated that clean bedded salt will be an excellent medium for scanning with an impulse radar. The impulse radar as it now exists can be used for WIPP applications

169

Stall Control Simulation with an Impulse Jet  

Science.gov (United States)

An impulse jet is investigated numerically to understand the mechanism by which this jet controls a stalled flow over an airfoil. The DDES (delayed detached eddy simulation) turbulence model is used in this stall control study for a NACA 4415 airfoil at an angle of attack of 20 degree and Reynolds number Re=570,000. An impulse jet, which is applied upstream of the nominal flow separation point, generates vortices that convect downstream, interact with the separating shear layer, dismantle the layer and allow following vortices to propagate along the surface in the separation region. These following vortices shift the separation point aft reattaching the boundary layer, which returns slowly to its initial stall condition, as observed in wind-tunnel experiments. A simple model of the impulse jet actuator used herein is found to be sufficient to represent the global effects of the jet on the stalled flow because it correctly represents the momentum injected into the flow.

Jee, Sol Keun; Moser, Robert; Lopez, Omar

2010-11-01

170

Intensity impulse response of SDM links.  

Science.gov (United States)

We study the response of space-division multiplexed fiber links to an excitation by a short impulse of the optical intensity. We show that, in the presence of full mixing, the intensity impulse response is Gaussian, confirming recently reported experimental observations, and relate its variance to the mean square of the mode dispersion vector of the link ??. The good agreement between our theory and the previously published experiments provides solid foundations to the random coupling model of SDM fiber links, and provides a tool for efficient design of MIMO-DSP receivers. PMID:25836803

Mecozzi, Antonio; Antonelli, Cristian; Shtaif, Mark

2015-03-01

171

Impulsive differential equations with a small parameter  

CERN Document Server

This book is devoted to impulsive differential equations with a small parameter. It consists of three chapters. Chapter One serves as an introduction. In Chapter Two, regularly perturbed impulsive differential equations are considered. Modifications of the method of small parameter, the averaging method, and the method of integral manifolds are proposed. In Chapter Three, singularly perturbed differential equations are considered. A modification of the method of boundary functions is proposed, and asymptotic expansions along the powers of the small parameters of the solutions of the initial va

Bainov, DD

1994-01-01

172

Lewis rats have greater response impulsivity than Fischer rats.  

Science.gov (United States)

Impulsivity, a tendency toward immediate action without consideration of future consequences, is associated with a wide array of problematic behaviors. Response impulsivity, a type of behaviorally-assessed impulsivity characterized by behavioral disinhibition, is also associated with health risk behaviors. Response impulsivity is distinct from choice impulsivity, which is characterized by intolerance for delay. Lewis rats have higher levels of choice impulsivity than Fischer rats (Anderson & Woolverton, 2005; Madden et al., 2008; Stein et al., 2012). However, no studies have examined whether Lewis and Fischer rats have different levels of response impulsivity. The present research examined response impulsivity in the two rat strains. Subjects were 16 male Lewis and Fischer rats. Rats' response impulsivity was measured using the Five Choice Serial Reaction Time Task (5-CSRTT). In addition, their locomotor activity was measured in locomotor activity chambers. Lewis rats had more premature responses than Fischer rats during the 5-CSRTT assessment [F(1, 14)=5.34, presponse impulsivity. Locomotor activity did not differ between rat strain groups [F(1, 14)=3.05, p=.10], suggesting that overall movement did not account for group differences in response impulsivity on the 5-CSRTT. It can be concluded from this research that Lewis rats have higher levels of response impulsivity than Fischer rats, and therefore provide a valid rat model of individual differences in impulsivity. PMID:24613059

Hamilton, Kristen R; Potenza, Marc N; Grunberg, Neil E

2014-11-01

173

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

Science.gov (United States)

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. PMID:8826795

Dittmar, H; Beattie, J; Friese, S

1996-09-01

174

Cortical thickness of superior frontal cortex predicts impulsiveness and perceptual reasoning in adolescence.  

Science.gov (United States)

Impulsiveness is a pivotal personality trait representing a core domain in all major personality inventories. Recently, impulsiveness has been identified as an important modulator of cognitive processing, particularly in tasks that require the processing of large amounts of information. Although brain imaging studies have implicated the prefrontal cortex to be a common underlying representation of impulsiveness and related cognitive functioning, to date a fine-grain and detailed morphometric analysis has not been carried out. On the basis of ahigh-resolution magnetic resonance scans acquired in 1620 healthy adolescents (IMAGEN), the individual cortical thickness (CT) was estimated. Correlations between Cloninger's impulsiveness and CT were studied in an entire cortex analysis. The cluster identified was tested for associations with performance in perceptual reasoning tasks of the Wechsler Intelligence Scale for Children (WISC IV). We observed a significant inverse correlation between trait impulsiveness and CT of the left superior frontal cortex (SFC; Monte Carlo Simulation P<0.01). CT within this cluster correlated with perceptual reasoning scores (Bonferroni corrected) of the WISC IV. On the basis of a large sample of adolescents, we identified an extended area in the SFC as a correlate of impulsiveness, which appears to be in line with the trait character of this prominent personality facet. The association of SFC thickness with perceptual reasoning argues for a common neurobiological basis of personality and specific cognitive domains comprising attention, spatial reasoning and response selection. The results may facilitate the understanding of the role of impulsiveness in several psychiatric disorders associated with prefrontal dysfunctions and cognitive deficits. PMID:22665261

Schilling, C; Kühn, S; Paus, T; Romanowski, A; Banaschewski, T; Barbot, A; Barker, G J; Brühl, R; Büchel, C; Conrod, P J; Dalley, J W; Flor, H; Ittermann, B; Ivanov, N; Mann, K; Martinot, J-L; Nees, F; Rietschel, M; Robbins, T W; Smolka, M N; Ströhle, A; Kathmann, N; Garavan, H; Heinz, A; Schumann, G; Gallinat, J

2013-05-01

175

A Model-based Analysis of Impulsivity Using a Slot-Machine Gambling Paradigm  

Directory of Open Access Journals (Sweden)

Full Text Available Impulsivity plays a key role in decision-making under uncertainty. It is a significant contributor to problem and pathological gambling. Standard assessments of impulsivity by questionnaires, however, have various limitations, partly because impulsivity is a broad, multi-faceted concept. What remains unclear is which of these facets contribute to shaping gambling behavior. In the present study, we investigated impulsivity as expressed in a gambling setting by applying computational modeling to data from 47 healthy male volunteers who played a realistic, virtual slot-machine gambling task. Behaviorally, we found that impulsivity, as measured independently by the 11th revision of the Barratt Impulsiveness Scale (BIS-11, correlated significantly with an aggregate read-out of the following gambling responses: bet increases, machines switches, casino switches and double-ups. Using model comparison, we compared a set of hierarchical Bayesian belief-updating models, i.e. the Hierarchical Gaussian Filter (HGF and Rescorla-Wagner reinforcement learning models, with regard to how well they explained different aspects of the behavioral data. We then examined the construct validity of our winning models with multiple regression, relating subject-specific model parameter estimates to the individual BIS-11 total scores. In the most predictive model (a three-level HGF, the two free parameters encoded uncertainty-dependent mechanisms of belief updates and significantly explained BIS-11 variance across subjects. Furthermore, in this model, decision noise was a function of trial-wise uncertainty about winning probability. Collectively, our results provide a proof of concept that hierarchical Bayesian models can characterize the decision-making mechanisms linked to impulsivity. These novel indices of gambling mechanisms unmasked during actual play may be useful for online prevention measures for at-risk players and future assessments of pathological gambling.

Saee Paliwal

2014-07-01

176

Asymptotical p-Moment Stability of Stochastic Impulsive Differential Equations and Its Application in Impulsive Control  

International Nuclear Information System (INIS)

In this paper, the asymptotical p-moment stability of stochastic impulsive differential equations is studied, and a comparison theory to ensure the asymptotical p-moment stability for trivial solution of this system is established, from which we can find out whether a stochastic impulsive differential system is stable just from a deterministic comparison system. As an application of this theory, we control the chaos of stochastic Chen system using impulsive method, and a stable region is deduced too. Finally, numerical simulations verify the feasibility of our method. (general)

177

A new Calculation Procedure for Spatial Impulse Responses in Ultrasound  

DEFF Research Database (Denmark)

A new procedure for the calculation of spatial impulse responses for linear sound fields is introduced. This calculation procedure uses the well known technique of calculating the spatial impulse response from the intersection of a circle emanating from the projected spherical wave with the boundary of the emitting aperture. This general result holds for all aperture boundaries for a flat transducer surface, and this is used in the procedure to yield the response for all types of flat transducers. An arbitrary apodization function over the aperture can be incorporated through a simple one-dimensional integration. The case of a soft baffle mounting of the aperture is also included. Specific solutions for transducer boundaries made from lines are given, so that any polygon transducer can be handled. Specific solutions for circles are also given. Finally, a solution for a general boundary is stated, and all these boundary elements can be combined to, e.g., handle annular arrays or semi-circle transducers. Results from an implementation of the approach are given and compared to previously developed solutions for a simple aperture, a complex aperture, and a Gaussian apodized circular transducer.

Jensen, JØrgen Arendt

1999-01-01

178

Hyperactive-Impulsive Symptoms Associated with Self-Reported Sleep Quality in Nonmedicated Adults with ADHD  

Science.gov (United States)

Objective: Individuals with ADHD often report sleep problems. Though most studies on ADHD and sleep examined children or nonclinically diagnosed adults, the present study specifically examines nonmedicated adults with ADHD to determine whether inattentive and hyperactive-impulsive symptoms are associated with sleep problems. Method: A total of 22…

Mahajan, Neha; Hong, Nuong; Wigal, Timothy L.; Gehricke, Jean-G.

2010-01-01

179

Flows of characteristic 0+ in impulsive semidynamical systems  

Science.gov (United States)

In this paper, as in [E.M. Bonotto, M. Federson, Topological conjugation and asymptotic stability in impulsive semidynamical systems, J. Math. Anal. Appl. (2006), ], we continue to study the dynamics of flows defined in impulsive semidynamical systems (X,[pi];M,I), where X is a metric space, (X,[pi]) is a semidynamical system, M denotes an impulsive set and I is an impulsive operator. We generalize some results of non-impulsive flows of characteristic 0+ () for systems with impulses. In particular, we state conditions so that the limit set of an impulsive system of is either a periodic orbit or a single rest point. We also give conditions for a subset H in (X,[pi];M,I) to be globally asymptotically stable in the impulsive system, provided the flow is of .

Bonotto, E. M.

2007-08-01

180

Does the repeated gambles procedure measure impulsivity in social drinkers.  

Science.gov (United States)

P. Sarfati and K. G. White (1991) found that heavy social drinkers were more risk averse than light drinkers in a repeated gambles procedure. Given a theoretical argument that risk aversion corresponds to impulsivity in this context, this result implied that heavy drinkers are more impulsive than light drinkers. The present study sought to replicate this finding, and, by administering questionnaire measures of impulsivity, to explore the relation between drinking and impulsivity as measured by the repeated gambles procedure and impulsivity as measured by questionnaires. Results showed more impulsivity among heavy drinkers than light drinkers on the questionnaires but not on choices during the repeated gambles procedure. These results question the utility of the repeated gambles procedure as a measure of impulsivity and as a useful vehicle for studying the drinking-impulsivity relation. PMID:9234053

Vuchinich, R E; Calamas, M L

1997-05-01

181

A Multitrait-Multimethod Analysis of Reflection-Impulsivity  

Science.gov (United States)

The relationship between reflection-impulsivity as assessed by Kagan's Matching Familiar Figures test, and ratings of four personality variables (impulsivity, academic achievement motivation, test anxiety, and extra-version was examined in 68 fifth-grade children. (BRT)

Bentler, P. M.; McClain, Janis

1976-01-01

182

Discrimination Learning and Stimulus Generalization by Impulsive and Reflective Children  

Science.gov (United States)

This study indicates that impulsive children inhibit expressive behavior less than reflective children in the presence of a nonverbal inhibitory cue, and provides support for the construct validity of the Matching Familiar Figures Test of reflectivity/impulsivity. (GO)

Stein, Norman; Prindaville, Patricia Steele

1976-01-01

183

Bright and dark sides of impulsivity: performance of women with high and low trait impulsivity on neuropsychological tasks.  

Science.gov (United States)

We administered a multidimensional measure of trait impulsivity (the UPPS-P impulsivity scale; Cyders et al., 2007) to a nonclinical sample of 155 individuals and selected 32 participants at the two ends of the trait impulsivity continuum: high (HI, n = 15) and low (LI, n = 17) impulsive women. We further tested these extreme groups on neuropsychological measures of motor impulsivity (go/no-go, d2), delay discounting (Now or Later Questionnaire), reflection impulsivity (Matching Familiar Figures Test), self-regulation (Revised-Strategy Application Test), and decision making (Iowa Gambling Task). High-trait-impulsivity women were found to commit more commission errors in the initial stage of the go/no-go task but also to make fewer omission errors in the d2 test than did low-trait-impulsivity women. Both effects can be accounted for by a lower response criterion in impulsive women. On the other hand, measures of delay discounting, reflection impulsivity, self-regulation, and decision making did not yield significant differences between the two groups. This pattern of results supports the idea that trait impulsivity in healthy women is linked to neurocognitive mechanisms involved in response monitoring and inhibition, but not to mechanisms involved in self-regulation or decision making. These findings temper the assumption that impulsivity is the core cause of dysfunctional risky and/or impulsive behavior in psychopathological or neuropsychological profiles. PMID:19358009

Perales, Jose C; Verdejo-Garcia, Antonio; Moya, Maribel; Lozano, Oscar; Perez-Garcia, Miguel

2009-11-01

184

Conception et caracterisation d'un magnetoplasma produit par une onde de surface pour la pulverisation d'echantillons solides  

Science.gov (United States)

Suite a l'extraordinaire explosion de l'informatique de la derniere decennie, la science et la technologie des materiaux ont pris un essor extraordinaire. Par exemple, il est devenu crucial de concevoir des materiaux a haut degre de purete. Ce besoin a fortement motive le developpement de methodes d'analyse de solides. Traditionnellement, la methode adoptee est l'analyse par torche ICP, mais pour de nombreuses raisons, dont la lenteur de cette methode, la communaute scientifique oeuvrant en chimie analytique recherche des techniques d'analyse de solides directes, rapides et plus sensibles. Parmi les voies possibles, on trouve les methodes basees sur la pulverisation par plasma. Dans ce contexte, nous avons etudie la possibilite et la pertinence d'utiliser un magnetoplasma entretenu par une onde de surface pour pulveriser des solides dans le but de les analyser. Nos travaux portent principalement sur l'etude du comportement du plasma lors de la pulverisation. Nous avons montre que la pulverisation affecte la decharge de diverses facons. En premier lieu, la concentration d'especes provenant du materiau pulverise dans le plasma augmente avec la tension de polarisation. De plus, la concentration d'especes pulverisees diminue lorsque la pression croit, possiblement a cause du redepot. Nous avons aussi montre qu'il etait possible de pulveriser des solides isolants en exploitant le phenomene d'autopolarisation du a l'application d'une tension RF. Nous avons aussi etudie l'effet de la pulverisation sur la temperature et la densite electronique. Ainsi, lors de la pulverisation de metaux tels que le cuivre, la temperature electronique diminue lorsque la tension de polarisation augmente. Ceci est attribuable a l'augmentation de la densite d'especes metalliques neutres facilement ionisables par impact electronique. Nous avons aussi note que la densite electronique augmente avec la concentration d'especes metalliques dans le plasma, ce qui resulte d'un meilleur bilan de puissance. Une etude des caracteristiques du plasma seul a revele que le champ magnetique confine si bien le plasma que le maximum de densite electronique se trouve hors axe, plus exactement a la position radiale correspondant au rayon du cylindre dielectrique servant a former l'interface dielectrique-plasma dans la zone source du reacteur. Ce phenomene indique une tres nette superiorite du coefficient de diffusion axial par rapport au coefficient de diffusion radial. Notre reacteur a un potentiel interessant pour l'analyse elementaire de materiaux solides puisque le taux de pulverisation y est eleve et que les especes pulverisees sont aisement excitees et ionisees par le plasma.

Masse, Louis Philippe

185

Impulsivity, self-regulation,and pathological video gaming among youth: testing a mediation model.  

Science.gov (United States)

Given the potential negative mental health consequences of pathological video gaming, understanding its etiology may lead to useful treatment developments. The purpose of the study was to examine the influence of impulsive and regulatory processes on pathological video gaming. Study 1 involved 2154 students from 6 primary and 4 secondary schools in Singapore. Study 2 involved 191 students from 2 secondary schools. The results of study 1 and study 2 supported the hypothesis that self-regulation is a mediator between impulsivity and pathological video gaming. Specifically, higher levels of impulsivity was related to lower levels of self-regulation, which in turn was related to higher levels of pathological video gaming. The use of impulsivity and self-regulation in predicting pathological video gaming supports the dual-system model of incorporating both impulsive and reflective systems in the prediction of self-control outcomes. The study highlights the development of self-regulatory resources as a possible avenue for future prevention and treatment research. PMID:22199156

Liau, Albert K; Neo, Eng Chuan; Gentile, Douglas A; Choo, Hyekyung; Sim, Timothy; Li, Dongdong; Khoo, Angeline

2015-03-01

186

Final report of LDRD project: Electromagnetic impulse radar for detection of underground structures  

Energy Technology Data Exchange (ETDEWEB)

This report provides a summary of the LDRD project titled: Electromagnetic impulse radar for the detection of underground structures. The project met all its milestones even with a tight two year schedule and total funding of $400 k. The goal of the LDRD was to develop and demonstrate a ground penetrating radar (GPR) that is based on high peak power, high repetition rate, and low center frequency impulses. The idea of this LDRD is that a high peak power, high average power radar based on the transmission of short impulses can be utilized effect can be utilized for ground penetrating radar. This direct time-domain system the authors are building seeks to increase penetration depth over conventional systems by using: (1) high peak power, high repetition rate operation that gives high average power, (2) low center frequencies that better penetrate the ground, and (3) short duration impulses that allow for the use of downward looking, low flying platforms that increase the power on target relative to a high flying platform. Specifically, chirped pulses that are a microsecond in duration require (because it is difficult to receive during transmit) platforms above 150 m (and typically 1 km) while this system, theoretically could be at 10 m above the ground. The power on target decays with distance squared so the ability to use low flying platforms is crucial to high penetration. Clutter is minimized by time gating the surface clutter return. Short impulses also allow gating (out) the coupling of the transmit and receive antennas.

Loubriel, G.; Aurand, J.; Buttram, M.; Zutavern, F.; Brown, D.; Helgeson, W.

1998-03-01

187

Impulsivity, aggression and brain structure in high and low lethality suicide attempters with borderline personality disorder.  

Science.gov (United States)

Impulsivity and aggressiveness are trait dispositions associated with the vulnerability to suicidal behavior across diagnoses. They are associated with structural and functional abnormalities in brain networks involved in regulation of mood, impulse and behavior. They are also core characteristics of borderline personality disorder (BPD), a disorder defined, in part, by recurrent suicidal behavior. We assessed the relationships between personality traits, brain structure and lethality of suicide attempts in 51 BPD attempters using multiple regression analyses on structural MRI data. BPD was diagnosed by the Diagnostic Interview for Borderline Patients-revised, impulsivity by the Barratt Impulsiveness Scale (BIS), aggression by the Brown-Goodwin Lifetime History of Aggression (LHA), and high lethality by a score of 4 or more on the Lethality Rating Scale (LRS). Sixteen High Lethality attempters were compared to 35 Low Lethality attempters, with no significant differences noted in gender, co-morbidity, childhood abuse, BIS or LHA scores. Degree of medical lethality (LRS) was negatively related to gray matter volumes across multiple fronto-temporal-limbic regions. Effects of impulsivity and aggression on gray matter volumes discriminated High from Low Lethality attempters and differed markedly within lethality groups. Lethality of suicide attempts in BPD may be related to the mediation of these personality traits by specific neural networks. PMID:24656768

Soloff, Paul; White, Richard; Diwadkar, Vaibhav A

2014-06-30

188

Non-smooth Approach for Contact Dynamics and Impulse-based Control of Frictional Furuta Pendulum  

CERN Document Server

In this thesis, a non-penetrated and physically consistent non-smooth numerical approach has been proposed, by employing the Prox formulation and Moreau's mid-point time-stepping rule, for the contact dynamics with coupled and decoupled constraints. Under this circumstance, the robust impulse-based control has been successfully implemented and validated on the motion system of controlled frictional oscillator. Further improvement has been achieved by utilizing shooting method in the impulse estimating process instead of robust estimation. This non-smooth numerical technique has been applied to the under-actuated friction-coupled mulit-body system, by means of an implementation on the controlled frictional Furuta pendulum. The specifically designed impulse-based controller has successfully solved the problem of stabilization of the inverted frictional Furuta pendulum, which is suffered from the stiction effect of friction.

Zhang, Hantian

2014-01-01

189

Improvement of impulse breakdown strength of an XLPE cable by modifing semiconducting layer  

Science.gov (United States)

A technique was investigated which reduces insulation thickness by improving breakdown strength of XLPE (cross-linked polyethylene) cables, using additives to improve interfaces of semiconducting layers, in order to restrain construction cost. Miniature model cables of 1mm insulation thick, 2mm diameter of inner semiconducting layer were manufactured. An additive was included in the semiconducting layer of each miniature cable to improve the interface with the insulating layer. The strength of dielectric breakdown was measured by testing of the impulsive pressure with lightning. The results of the impulse breakdown test show a rise in breakdown strength, indicating the effective function to make interface defects harmless. Based on the results of a previous report, a specific kind of additive which has an excellent function to improve both ac and impulse breakdown strength was selected. Additives used in this test are mainly nonionic surface active agents such as polyglyceric fatty acid esters.

Hozumi, N.; Okamoto, T.; Ishida, M.

1988-09-01

190

Impulse response functions for periodic integration  

OpenAIRE

A quarterly observed time series is said to be periodically integrated [PI] if the stochastic trend needs to be removed by a seasonally varying differencing filter. In this paper we consider the impulse response functions [IRF] for such a PI time series.

Franses, Ph H. B. F.; Breitung, J.

1997-01-01

191

Impulse response of a nonlinear dispersive wave  

International Nuclear Information System (INIS)

The spatiotemporal instability of a nonlinear wave is studied by applying impulse-response analysis. The time-asymptotic Green function is obtained analytically for both modulationally stable and unstable cases. The conditions for absolute and convective instability are found analytically, as is the frequency region for amplification and the spatial and temporal growth rates. (c) 1995 The American Physical Society

192

Dopamine, Time, and Impulsivity in Humans  

OpenAIRE

Disordered dopamine neurotransmission is implicated in mediating impulsiveness across a range of behaviors and disorders including addiction, compulsive gambling, attention-deficit/hyperactivity disorder, and dopamine dysregulation syndrome. Whereas existing theories of dopamine function highlight mechanisms based on aberrant reward learning or behavioral disinhibition, they do not offer an adequate account of the pathological hypersensitivity to temporal delay that forms a crucial behavioral...

Pine, Alex; Shiner, Tamara; Seymour, Ben; Dolan, Raymond J.

2010-01-01

193

Impulse Plasma In Surface Engineering - a review  

Science.gov (United States)

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.

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

2014-11-01

194

Arbitration between controlled and impulsive choices.  

Science.gov (United States)

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

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

2015-04-01

195

The Hydraulic Ram (Or Impulse) Pump  

Science.gov (United States)

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,…

Mills, Allan

2014-01-01

196

Recursive Inversion By Finite-Impulse-Response Filters  

Science.gov (United States)

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.

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

1991-01-01

197

Asymmetric generalized impulse responses and variance decompositions with an application  

OpenAIRE

This paper introduces asymmetric impulse response functions and asymmetric variance decompositions. It is shown how the underlying variables can be transformed into cumulative positive and negative changes in order to estimate the impulses to an asymmetric innovation. An application is provided to demonstrate how the propagation mechanism of these asymmetric impulses and responses operates.

Hatemi-j, Abdulnasser

2011-01-01

198

Borderline personality disorder, impulsivity, and the orbitofrontal cortex.  

OpenAIRE

OBJECTIVE: Orbitofrontal cortex lesions produce disinhibited or socially inappropriate behavior and emotional irregularities. Characteristics of borderline personality disorder include impulsivity and affective instability. The authors investigated whether aspects of borderline personality disorder, in particular impulsivity, are associated with orbitofrontal cortex dysfunction. METHOD: Measures of personality, emotion, impulsivity, time perception, sensitivity to reinforcers, and spatial wor...

Berlin, Ha; Rolls, Et; Iversen, Sd

2005-01-01

199

Stabilization of complex network with hybrid impulsive and switching control  

International Nuclear Information System (INIS)

This paper studies the asymptotic stability properties of a class of complex dynamical networks under a hybrid impulsive and switching control. By utilizing the concept of impulsive control and the stability results for impulsive systems, some new criteria for global and local stability are established for this model. Some numerical examples and simulations are included to illustrate the effectiveness of the theoretical results

200

Adaptive-impulsive synchronization of uncertain complex dynamical networks  

International Nuclear Information System (INIS)

This Letter studies adaptive-impulsive synchronization of uncertain complex dynamical networks. Based on the stability analysis of impulsive system, several network synchronization criteria for local and global adaptive-impulsive synchronization are established. Numerical example is also given to illustrate the results

201

Models of Impulsivity with a Focus on Waiting Impulsivity: Translational Potential for Neuropsychiatric Disorders  

OpenAIRE

Waiting impulsivity, also known as premature or anticipatory responding, is well established in preclinical studies through the 5-Choice Serial Reaction Time (5-CSRT) task. Waiting impulsivity is important in disorders of addiction. Preclinical studies suggest a role both as a predictor, and as a consequence, in disorders of addiction. Here we discuss the relationship between the preclinical 5-CSRT and translational fidelity in newly developed translational tasks. Preclinical and clinical lit...

Voon, Valerie

2014-01-01

202

Flare kernel in the impulsive phase  

International Nuclear Information System (INIS)

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

203

Single-photon emission tomography imaging of monoamine transporters in impulsive violent behaviour  

International Nuclear Information System (INIS)

Several studies have shown that impulsive violent and suicidal behaviour is associated with a central serotonin deficit, but until now it has not been possible to use laboratory tests with high sensitivity and specificity to study this kind of deficit or to localize the sites of serotonergic abnormalities in the living human brain. The aim of this study was to test the hypothesis that monoamine transporter density in brain is decreased in subjects with impulsive violent behaviour. We studied serotonin (5-HT) and dopamine (DA) transporter specific binding in 52 subjects (21 impulsive violent offenders, 21 age- and sex-matched healthy controls, and ten non-violent alcoholic controls) with single-photon emission tomography (SPET) using iodine-123-labelled 2?-carbomethoxy-3?(4-iodophenyl)tropane ([123I]?-CIT) as the tracer. The blind quantitative analysis revealed that the 5-HT specific binding of [123I]?-CIT in the midbrain of violent offenders was lower than that in the healthy control subjects (P<0.005; t test) or the non-violent alcoholics (P<0.05). The results imply that habitual impulsive aggressive behaviour in man is associated with a decrease in the 5-HT transporter density. (orig.)

204

Impulse response in various scanning geometries for digital tomosynthesis  

International Nuclear Information System (INIS)

Digital tomosynthesis (DTS) is a three-dimensional imaging technique to reconstruct a set of planes in the object. Opposed to the computed tomography (CT), however, DTS uses projection images obtained from limited angular scanning, hence there exist some artifacts such as blurs that are originated from depletion of data in the Fourier domain. The main advantages of DTS technique are shorter reconstruction time and less patient dose. There are various geometries for angular scanning available in DTS, and which is mainly dependent upon specific imaging task and applications, such as mammography, dental imaging, industrial laminography etc. In principle, DTS shares the same concept in imaging reconstruction with the conventional CT, and thus incorporates a back-projection operation. This backprojection operation determines the transfer function, which is mainly resulted from the scanning geometry, if we regard the image reconstruction as an inverse problem. Therefore, the investigation of impulse response with respect to various imaging geometries is valuable to identify artifacts associated with the scanning geometry and thus optimize the system performance. We investigate and compare the system-transfer functions (impulse-response functions) for various image acquisition schemes to acquire projection data by numerical simulation. This study may suggest fundamental limitations of a certain scanning geometry and provide the best geometry with least blur artifactsgeometry with least blur artifacts

205

LMFBR core flowering response to an impulse load  

International Nuclear Information System (INIS)

Some incidental situations like MFCI (Meeting Fuel Coolant Incident) may induce a core flowering and lead to consider impulse loans applied to LMFBR core. These highly dynamic loads are very different considering their spatial repartition and their frequency content from the seismic loads which have been deeply studied. Recently, tests have been performed on the LMFBR core mock-up RAPSODIE in order to validate the calculation methods for centered impulse load. These tests consist in injecting water quickly in the mock-up through a specific device replacing the core central assembly. The influence of the injection pressure and the influence of the injection axial position have been investigate. During the tests, the top displacements of some assemblies have been measured. The aim of this paper is first to present the experimental device and the test results. Then a non linear numerical model is described; this model includes the impact between subassemblies and is based on an homogenization method allowing to take into account with accuracy the fluid structure interaction.The comparisons between calculation results an test results will finally be presented

206

Mechanical impulses can control metaphase progression in a mammalian cell.  

Science.gov (United States)

Chromosome segregation machinery is controlled by mechanochemical regulation. Tension in a mitotic spindle, which is balanced by molecular motors and polymerization-depolymerization dynamics of microtubules, is thought to be essential for determining the timing of chromosome segregation after the establishment of the kinetochore-microtubule attachments. It is not known, however, whether and how applied mechanical forces modulate the tension balance and chemically affect the molecular processes involved in chromosome segregation. Here we found that a mechanical impulse externally applied to mitotic HeLa cells alters the balance of forces within the mitotic spindle. We identified two distinct mitotic responses to the applied mechanical force that either facilitate or delay anaphase onset, depending on the direction of force and the extent of cell compression. An external mechanical impulse that physically increases tension within the mitotic spindle accelerates anaphase onset, and this is attributed to the facilitation of physical cleavage of sister chromatid cohesion. On the other hand, a decrease in tension activates the spindle assembly checkpoint, which impedes the degradation of mitotic proteins and delays the timing of chromosome segregation. Thus, the external mechanical force acts as a crucial regulator for metaphase progression, modulating the internal force balance and thereby triggering specific mechanochemical cellular reactions. PMID:22523237

Itabashi, Takeshi; Terada, Yasuhiko; Kuwana, Kenta; Kan, Tetsuo; Shimoyama, Isao; Ishiwata, Shin'ichi

2012-05-01

207

LMFBR core flowering response to an impulse load  

International Nuclear Information System (INIS)

Some incidental situations like MFCI (Meeting Fuel Coolant Incident) may induce a core flowering and lead to consider impulse loads applied to LMFBR core. These highly dynamic loads are very different considering their spatial repartition and their frequency content from the seismic loads which have been deeply studied. Recently, tests have been performed on the LMFBR core mock-up RAPSODIE in order to validate the calculation methods for centered impulse load. These tests consist in injecting water quickly in the mock-up through a specific device replacing the core central assembly. The influence of the injection pressure and the influence of the injection axial position have been investigated. During the tests, the top displacements of some assemblies have been measured. The aim of this paper is first to present the experimental device and the test results. Then a non linear numerical model is described; this model includes the impact between subassemblies and is based on an homogenization method allowing to take into account with accuracy the fluid structure interaction. The comparisons between calculation results and test results will finally be presented

208

Clarifying the relationship between impulsive delay discounting and nicotine dependence.  

Science.gov (United States)

Impulsive delayed reward discounting (DRD) has been linked to nicotine dependence, but with some inconsistency. This may be related to the considerable variability in the literature with regard to the DRD assessments used, particularly in the case of the reward magnitudes assessed. In addition, previous studies have often not considered concurrent substance use when examining the relationship between DRD and nicotine dependence. The current study sought to further clarify the relationship between DRD and nicotine dependence by characterizing DRD across diverse reward magnitudes and incorporating other substance use. Daily smokers (N = 933) were assessed for DRD preferences across nine reward magnitudes (delayed reward range: $2.50-$850), comorbid substance use, and relevant demographic variables (age, education, income). A significant large effect size magnitude effect was found for DRD, reflecting steeper discounting for smaller delayed rewards, but significant correlations across magnitudes also suggested similar relative levels of discounting. Principal components analysis (PCA) was used to generate a single latent index of discounting across all magnitudes that accounted for 69% of the total variance. In correlation and regression analyses, steeper composite DRD was significantly associated with nicotine dependence severity. This relationship remained statistically significant after incorporating demographic variables and alcohol and illicit drug use. These findings provide evidence of a specific link between impulsive DRD and nicotine dependence and reveal that this association is robust across a broad range of monetary rewards. The study also demonstrates the utility of using PCA to generate latent indices of delay discounting across multiple magnitudes of delayed reward. PMID:24841186

Amlung, Michael; MacKillop, James

2014-09-01

209

[Anti-impulsivity drugs and their mechanisms of action].  

Science.gov (United States)

Higher impulsivity could be a risk factor for drug addiction, criminal involvement, and suicide. Moreover, poor inhibitory control is observed in several psychiatric disorders such as attention-deficit/hyperactivity disorder, schizophrenia, and bipolar disorder. Thus it is preferred that clinical drugs have anti-impulsive effects in addition to the therapeutic effects on the primary disease. At least it is better to use clinical drugs that do not increase impulsivity. We have developed a 3-choice serial reaction time task and examined the effects of clinical drugs on impulsivity in rats using the task. We have found several anti-impulsive drugs (lithium, tandospirone, and milnacipran) and elucidated the mechanism of action in some of these drugs. For example, we demonstrated that milnacipran enhanced the control of impulsive action by activating D1-like receptors in the infralimbic cortex. In this review, we introduce recent advances in this field and suggest future directions to develop anti-impulsive drugs. PMID:25080806

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

2014-04-01

210

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

Science.gov (United States)

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. PMID:24864028

Grant, Jon E; Chamberlain, Samuel R

2014-11-01

211

Thin foil electron beam impulse experiments  

International Nuclear Information System (INIS)

Measurements were made of the impulse produced by thin, metallic foils that had been rapidly and uniformly heated in depth, to melt or vaporization by an electron beam. Blowoff predictions were done using two hydrocodes: PUFF, with the GRAY three phase equation of state, and CHART, with its three phase equation of state. An acceptable correlation variable, folding in electron beam and material characteristics, was derived and used successfully to plot and analyze predicted and measured data trends. We conclude that PUFF and CHART, with their present equations of state, predict impulse correctly within tolerances of +-30 percent. Unfortunately, the lack of repeatability of the electron beam machine precludes its use for doing more accurate equation of state measurements. (9 figs, 5 tables, 10 refs.) (auth)

212

Pinning impulsive control algorithms for complex network  

International Nuclear Information System (INIS)

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

213

Design and construction of an impulse turbine  

Science.gov (United States)

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.

Hernández, E.

2013-11-01

214

Filament-driven impulsive Raman spectroscopy.  

Science.gov (United States)

Vibrational Raman spectroscopy is performed in the gas phase using a femtosecond laser pulse undergoing filamentation as an impulsive excitation source. The molecular coherence induced by the filamentary pulse is subsequently probed using a narrowband, sub-picosecond laser pulse to produce Raman spectra of gas phase species in a few tens of milliseconds (~10 laser shots). Pulse shortening with concomitant spectral broadening during filamentation results in a pulse that is both sufficiently short and of sufficient spectral power density to impulsively excite the highest energy ground state vibrations (up to 4158 cm(-1) corresponding to H(2)). Gas phase detection of chloroform, methylene chloride, cyclohexane, toluene, pentane, triethylamine, ammonia, nitromethane, and gasoline is performed. PMID:21977899

Odhner, Johanan H; McCole, Erin T; Levis, Robert J

2011-11-24

215

Initial experience of acoustic radiation force impulse ultrasound imaging of cervical lymph nodes  

International Nuclear Information System (INIS)

The aim of this study was to evaluate acoustic radiation force impulse imaging for cervical lymphadenopathy in routine clinical practice and to correlate the acoustic radiation force impulse values with the morphological signs and the pathological results, which were used as the reference standard. The virtual touch tissue quantification values were analyzed in 123 patients (mean age 40.8 years, range 1–81 years) with 181 cervical lymph nodes (87 benign, 94 malignant). The diagnostic performance of acoustic radiation force impulse values were evaluated with respect to sensitivity, specificity, and area under the curve using a receiver operating characteristic curve analysis. The mean virtual touch tissue quantification values of the benign lesions (2.01 ± 0.95 m/s) differed from that of the malignant lesions (4.61 ± 2.56 m/s; P < 0.001). The cutoff level for virtual touch tissue quantification value for malignancy was estimated to be 2.595 m/s. Using the receiver operating characteristic curve curves with the cutoff value, the virtual touch tissue quantification value predicted malignancy with a sensitivity of 82.9%, specificity of 93.1% and gave an areas under the curve of 0.906 (95% CI 0.857–0.954). Acoustic radiation force impulse is feasible for cervical lymph nodes and provides quantitative elasticity measurements, which may complement B-mode ultrasound and potentially improve the characterization of cervical lymph nodes

216

Bending Wavelet for Flexural Impulse Response  

OpenAIRE

The work addresses the definition of a wavelet that is adapted to analyse a flexural impulse response. The wavelet gives the opportunity to directly analyse the dispersion characteristics of a pulse. The aim is to localize a source or to measure material parameters. An overview of the mathematical properties of the wavelet is presented. An algorithm to extract the dispersion characteristics with the use of genetic algorithms is outlined. The application of the wavelet is sho...

Buessow, Richard

2006-01-01

217

Nonparametric Estimation of Generalized Impulse Response Function  

OpenAIRE

A local linear estimator of generalized impulse response (GIR) functions for nonlinear conditional heteroskedastic autoregressive processes is derived and shown to be asymptotically normal. A plug-in bandwidth is obtained that minimizes the asymptotical mean squared error of the GIR estimator. A local linear estimator for the conditional variance function is proposed which has simpler bias than the standard estimator. This is achieved by appropriately eliminating the conditional mean. Alterna...

Tschernig, Rolf; Yang, Lijian

2000-01-01

218

Generalized Impulse Response Analysis: General or Extreme?  

OpenAIRE

This note discusses a pitfall of using the generalized impulse response function (GIRF) in vector autoregressive (VAR) models (Pesaran and Shin, 1998). The GIRF is general because it is invariant to the ordering of the variables in the VAR. The GIRF, in fact, is extreme because it yields a set of response functions that are based on extreme identifying assumptions that contradict each other, unless the covariance matrix is diagonal. With a help of empirical examples, the present note demonstr...

Hyeongwoo, Kim

2009-01-01

219

Impulse response measurement of ultrasonic transducers  

OpenAIRE

Digital processing of acoustic signals introduces pulses to measurement of impedances and transfer functions of ultrasonic systems. Digital impulse measurements of electroacoustic transducers described in the paper are based on comparison between the Fourier transforms of the input signals and the responses of the ultrasonic systems. Measuring signals consisting of two separate parts have been used where the power piezoelectric transducer is the input part of the system. Similarly, the output...

Kadlec, F.

1994-01-01

220

Acoustic radiation force impulse of the liver  

OpenAIRE

Acoustic radiation force impulse (ARFI) imaging is a new and promising ultrasound-based diagnostic technique that, evaluating the wave propagation speed, allows the assessment of the tissue stiffness. ARFI is implemented in the ultrasound scanner. By short-duration acoustic radiation forces (less than 1 ms), localized displacements are generated in a selected region of interest not requiring any external compression so reducing the operator dependency. The generated wave scan provides qualita...

Onofrio, Mirko D. X.; Stefano Crosara; Riccardo De Robertis; Stefano Canestrini; Emanuele Demozzi; Anna Gallotti; Roberto Pozzi Mucelli

2013-01-01

221

FEM Analysis of Turgo Impulse Turbine Blade  

Directory of Open Access Journals (Sweden)

Full Text Available The present research work describes the development of Turgo turbine blades on the Solidworks software. Finite element simulation (Ansys V14 has been used for analysis of stress and total deformation produced inside the Turgo impulse turbine. Finite element simulation is effective when it is used to analyze the strain and stress distribution. It has been observed during analysis that the maximum stress occurs at the root of blade suction side.

Sourabh KHURANA

2013-08-01

222

Normalization, probability distribution, and impulse responses  

OpenAIRE

When impulse responses in dynamic multivariate models such as identified VARs are given economic interpretations, it is important that reliable statistical inferences be provided. Before probability assessments are provided, however, the model must be normalized. Contrary to the conventional wisdom, this paper argues that normalization, a rule of reversing signs of coefficients in equations in a particular way, could considerably affect the shape of the likelihood and thus probability bands f...

Waggoner, Daniel F.; Zha, Tao

1997-01-01

223

FEM Analysis of Turgo Impulse Turbine Blade  

OpenAIRE

The present research work describes the development of Turgo turbine blades on the Solidworks software. Finite element simulation (Ansys V14) has been used for analysis of stress and total deformation produced inside the Turgo impulse turbine. Finite element simulation is effective when it is used to analyze the strain and stress distribution. It has been observed during analysis that the maximum stress occurs at the root of blade suction side.

Khurana, Sourabh; Goel, Varun; Kumar, Anoop

2013-01-01

224

Robust Algorithm for Impulse Noise Reduction  

OpenAIRE

This Paper presents highly efficient two phase schema for removing impulse noise. In the first phase, robust algorithm for noise detection is used to identify noisy pixels. In the second phase, the image is restored using special noise control algorithm. Efficiency of algorithm is tested by comparing with most powerful AMF (Adaptive Median Filter), DBA (Decision Based algorithm) and MTND (Median Type Noise Detector). Anexperimental result shows that the proposed algorithm works efficiently up...

Manohar Annappa Koli

2010-01-01

225

Impulse Noise removal in Digital Images  

OpenAIRE

In this paper, we introduce a new class of filter, the modified spatial median filter (MSMF) for the removal of impulse noise in digital images. The proposed filter is compared with four different filtering algorithms based on their ability to reconstruct noise-affected images. In-order to better appraise the noise cancellation behavior of our filter from the point of view of human perception, we perform edge detection using canny filter. Experimental results show that the filtering performan...

M.JayaManmadhaRao,; S.Anuradha,; Kvvs, Dr Reddy

2010-01-01

226

Impulse approximation versus elementary particle method  

International Nuclear Information System (INIS)

Calculations are made for radiative muon capture in 3He, both in impulse approximation and with the elementary particle method, and results are compared. It is argued that a diagrammatic method which takes a selected set of Feynman diagrams into account only provides insufficient warrant that effects not included are small. Therefore low-energy theorems are employed, as first given by Adler and Dothan, to determine the amplitude up to and including all terms linear in photon momentum and momentum transfer at the weak vertex. This amplitude is applied to radiative muon capture with the elementary particle method (EPM). The various form factors needed are discussed. It is shown that the results are particularly sensitive to the ?-3He-3H coupling constant of which many contradictory determinations have been described in the literature. The classification of the nuclear wave function employed in the impulse approximation (IA) is summarized. The ?-decay of 3H and (radiative muon capture in 3He is treated and numerical results are given. Next, pion photoproduction and radiative pion capture are considered. IA and EPM for radiative muon capture are compared more closely. It is concluded that two-step processes are inherently difficult; the elementary particle method has convergence problems, and unknown parameters are present. In the impulse approximation, which is perhaps conceptually more difficult, the two-step interaction for the nucleon is considered as effectively point-like with small non-local corrections. (Auth.)

227

Development of the relativistic impulse approximation  

International Nuclear Information System (INIS)

This talk contains three parts. Part I reviews the developments which led to the relativistic impulse approximation for proton-nucleus scattering. In Part II, problems with the impulse approximation in its original form - principally the low energy problem - are discussed and traced to pionic contributions. Use of pseudovector covariants in place of pseudoscalar ones in the NN amplitude provides more satisfactory low energy results, however, the difference between pseudovector and pseudoscalar results is ambiguous in the sense that it is not controlled by NN data. Only with further theoretical input can the ambiguity be removed. Part III of the talk presents a new development of the relativistic impulse approximation which is the result of work done in the past year and a half in collaboration with J.A. Tjon. A complete NN amplitude representation is developed and a complete set of Lorentz invariant amplitudes are calculated based on a one-meson exchange model and appropriate integral equations. A meson theoretical basis for the important pair contributions to proton-nucleus scattering is established by the new developments. 28 references

228

Parameter correlation of impulse shapes using two-port synthesis  

Science.gov (United States)

Standard techniques for testing devices and systems for their response to lightning, switching transients, and electromagnetic pulse (EMP) disturbances often call for impulse shapes characterized by double exponential functions. Unfortunately, the time constants and impulse parameters such as rise time, pulse, duration, time to peak, and others are not directly related. The problem in generating test impulses is that the required standard impulses are sometimes defined by parameters and nomenclature lacking direct correlation to the desired time constants needed to derive component values for prototype impulse generator circuits. This paper derives equations for determining the time constants of the double exponential impulse from the commonly used parameters for several standard test impulses. It then proceeds to synthesize a resistor-capacitor (RC) prototype circuit that will produce the desired impulse. The prototype network is realized through a computer-aided design (CAD) procedure using Cauer's RC ladder two-port synthesis method. Descriptions of prototype circuits and test data comparing the theoretical and experimental impulse shapes are also included. The results are a simplified method for determining time constants of a double exponential function from given impulse parameters and a method for deriving the component values for prototype circuits.

Googe, J. M.; Ewing, P. D.; Hess, R. A.

1991-05-01

229

Parameter correlation of impulse shapes using two-port synthesis  

Energy Technology Data Exchange (ETDEWEB)

Standard techniques for testing devices and systems for their response to lightning, switching transients, and electromagnetic pulse (EMP) disturbances often call for impulse shapes characterized by double exponential functions. Unfortunately, the time constants and impulse parameters such as rise time, pulse, duration, time to peak, and others are not directly related. The problem in generating test impulses is that the required standard impulses are sometimes defined by parameters and nomenclature lacking direct correlation to the desired time constants needed to derive component values for prototype impulse generator circuits. This paper derives equations for determining the time constants of the double exponential impulse from the commonly used parameters for several standard test impulses. It then proceeds to synthesize a resistor-capacitor (RC) prototype circuit that will produce the desired impulse. The prototype network is realized through a computer-aided design (CAD) procedure using Cauer's RC ladder two-port synthesis method. Descriptions of prototype circuits and test data comparing the theoretical and experimental impulse shapes are also included. The results are a simplified method for determining time constants of a double exponential function from given impulse parameters and a method for deriving the component values for prototype circuits. 7 refs., 8 figs.

Googe, J.M.; Ewing, P.D.; Hess, R.A.

1991-01-01

230

The integrated design of powder aligning and impulse magnetizing systems  

International Nuclear Information System (INIS)

This paper describes an integrated finite element based methodology for the design and analysis of powder aligning systems and impulse magnetizing fixtures for the manufacture of anisotropic bonded Nd Fe B permanent magnet components. The relationships between the final component properties and the magnitudes of the aligning field and subsequent magnetizing field are illustrated by extensive experimental characterization of a commercial grade of anisotropic Nd Fe B injection moulding compound (Compodic NDA502E). The modelling techniques employed are experimentally validated by a case study on a 4 pole self-shielding rotor, the mould and fixture parameters for which were specifically selected to produce only partial alignment and saturation. The utility of an automated design technique is illustrated by the optimization of a mould to achieve near full alignment and saturation of the 4 pole rotor. (author)

231

Impulsive and reflective processes related to alcohol use in young adolescents  

Directory of Open Access Journals (Sweden)

Full Text Available Background: Dual process models suggest that the development of addictive behaviors is the result of interplay between impulsive and reflective processes, modulated by boundary conditions such as individual or situational factors. Empirical support for this model has been repeatedly demonstrated in adult samples (for a meta-analysis see Rooke, Hine, & Thorsteinsson, 2008. The purpose of this study was to test these processes as they relate to emerging alcohol use in adolescents. Specifically, the interactive effects of several measures of impulsive and reflective processes and working memory capacity are examined as predictors of changes in alcohol use among adolescents. It was expected that measures of reflective processes would better predict changes in alcohol use than measures of impulsive processes. Moreover, it was anticipated that working memory capacity would moderate the relation between alcohol-specific impulsive and reflective processes and changes in adolescent alcohol use. Methods: The sample consisted of 427 adolescents (47.7% male between 12 and 16 years of age (M = 13.96, SD = .78 who reported drinking alcohol at least once. Four measures of impulsive processes were included. Attentional bias for alcohol was assessed with a Visual Probe Test; approach bias toward alcohol was assessed with a Stimulus Response Compatibility Test (SRC; and memory associations with alcohol were assessed with an Implicit Association Test (IAT and a Word Association Test (WAT. Two measures of reflective measures were included: positive and negative expectancies. Working memory capacity was measured using a Self-Ordered Pointing Task (SOPT. Results: Results showed that positive expectancies predicted changes in alcohol use, but this effect was qualified by an interaction with IAT scores. Moreover, SRC scores predicted changes in alcohol use only when negative expectancies were low. Attentional bias and word association scores did not predict changes in alcohol us

SaraPieters

2014-05-01

232

Alcoholics Anonymous and reduced impulsivity: a novel mechanism of change.  

Science.gov (United States)

ABSTRACT   Reduced impulsivity is a novel, yet plausible, mechanism of change associated with the salutary effects of Alcoholics Anonymous (AA). Here, the authors review their work on links between AA attendance and reduced impulsivity using a 16-year prospective study of men and women with alcohol use disorders (AUDs) who were initially untreated for their drinking problems. Across the study period, there were significant mean-level decreases in impulsivity, and longer AA duration was associated with reductions in impulsivity. In turn, decreases in impulsivity from baseline to Year 1 were associated with fewer legal problems and better drinking and psychosocial outcomes at Year 1, and better psychosocial functioning at Year 8. Decreases in impulsivity mediated associations between longer AA duration and improvements on several Year 1 outcomes, with the indirect effects conditional on participants' age. Findings are discussed in terms of their potential implications for research on AA and, more broadly, interventions for individuals with AUDs. PMID:23327499

Blonigen, Daniel M; Timko, Christine; Moos, Rudolf H

2013-01-01

233

The Relationship between Impulsive and Reflective Problem Solving Behavior  

Directory of Open Access Journals (Sweden)

Full Text Available Background: Problem solving is an axial ability of educational promotion. Impulsive individual against reflectivity has fewer tendencies to involve in solving different problems. The purpose of present study was to evaluate the correlation between impulsivity, need for cognition and problem solving performance.Materials and Method: In this study, 72 individuals were randomly selected. Missionaries and cannibal's problem, Barrat Impulsivity Scale (BIS-11 and need for cognition scale were used for evaluation. Results: Findings show negative correlation between problem solving performance and impulsivity and positive correlation between problem solving and need for cognition. Duration of problem solving was not correlated with need for cognition and impulsivity.Conclusion: Pearson coefficient of correlation show that individuals with high level of need for cognition had better performance in problem solving accuracy but duration of problem solving is not related to impulsivity and need for cognition

Vahid Nejati

2012-03-01

234

Alcoholics Anonymous and Reduced Impulsivity: A Novel Mechanism of Change  

OpenAIRE

Reduced impulsivity is a novel, yet plausible, mechanism of change associated with the salutary effects of Alcoholics Anonymous (AA). Here, we review our work on links between AA attendance and reduced impulsivity using a 16-year prospective study of men and women with alcohol use disorders (AUD) who were initially untreated for their drinking problems. Across the study period, there were significant mean-level decreases in impulsivity, and longer AA duration was associated with reductions in...

Blonigen, Daniel M.; Timko, Christine; Moos, Rudolf H.

2013-01-01

235

Causal impulse response for circular sources in viscous media  

OpenAIRE

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 fie...

Kelly, James F.; Mcgough, Robert J.

2008-01-01

236

Deletion of alpha-synuclein decreases impulsivity in mice  

OpenAIRE

The presynaptic protein alpha-synuclein, associated with Parkinson's Disease (PD), plays a role in dopaminergic neurotransmission and is implicated in impulse control disorders (ICDs) such as drug addiction. In this study we investigated a potential causal relationship between alpha-synuclein and impulsivity, by evaluating differences in motor impulsivity in the 5-choice serial reaction time task (5-CSRTT) in strains of mice that differ in the expression of the alpha-synuclein gene. C57BL/6JO...

Pen?a-oliver, Y.; Buchman, V. L.; Dalley, J. W.; Robbins, T. W.; Schumann, G.; Ripley, T. L.; King, S. L.; Stephens, D. N.

2011-01-01

237

FPGA IMPLEMENTATION AND ANALYSIS OF IMPULSE NOISE REDUCTION IN IMAGES  

OpenAIRE

The images are affected by random valued impulse noises during the image capturing and processing stages. In this study, an efficient, high performance and low hardware utilized impulse noise reduction algorithm is presented. This methodology determines the optimum direction pixels through the estimation of standard deviation. The edges in the images are preserved during the process of impulse noise detection and removal stage. The hardware architecture for this design is proposed and its per...

Thirumurugan, P.; Sasikumar, S.; Sugapriya, C.

2014-01-01

238

Boundary conditions of the exact impulse wave function  

International Nuclear Information System (INIS)

The behavior of the exact impulse wave function is investigated at intermediate and high impact energies. Numerical details of the wave function and its perturbative potential are reported. We conclude that the impulse wave function does not tend to the proper Coulomb asymptotic limit. For electron capture, however, it is shown that the impulse wave function produces reliable probabilities even for intermediate velocities and symmetric collision systems. copyright 1997 The American Physical Society

239

Virtual Shopping and Impulse Purchasing Strengths and Weaknesses in Pakistan  

OpenAIRE

This research analyzed the perceptive of consumers doing online shopping and impulse purchasing. This study examined the behavior of thirty consumers who were asked to fill the questionnaire based on some close ended questions. The focus of this investigation was to discuss the strengths and Weaknesses of online shopping and impulse purchasing in developing country like Pakistan. Today consumers choose and buy things while sitting at home through internet and buy things impulsively. Do consum...

Muhammad Ali Hussain; Muhammad Zeeshan Anwar; Humna Mehboob; Ayesha Majeed; Tanzila Samin

2011-01-01

240

Impulsive consumption and reflexive thought: Nudging ethical consumer behavior  

OpenAIRE

The paper deals with impulsive consumption and highlights the roles that cognitive and motivational aspects of reflexive thought (namely self-control and self-image motives, respectively) play in intertemporal decisions. While self-control inhibits individuals from consuming impulsively, self-image motives can induce impulsive consumption. Based on recent neuroscientific findings about 'wanting'-'liking' dissociations, the paper presents a potential motivational mechanism underlying such impu...

Lades, Leonhard K.

2012-01-01

241

Dopamine precursors depletion impairs impulse control in healthy volunteers.  

Science.gov (United States)

The aim of the present study was to decipher the role of the dopamine system in impulse control. Impulsive actions entail (i) activation of the motor system by an impulse, which is an urge to act and (ii) a failure to suppress that impulse, when inappropriate, in order to prevent an error. These two aspects of action impulsivity can be experimentally disentangled in conflict reaction time tasks such as the Simon task, which measures susceptibility to acting on spontaneous impulses (as well as the proficiency of suppressing these impulses). In 12 healthy volunteers performing a Simon task, dopamine availability was reduced with an amino acid drink deficient in the dopamine precursors, phenylalanine and tyrosine. Classic behavioral measures were augmented with an analysis of the electromyographic activity of the response effectors. Electromyography allows one to detect covert activations undetectable with strictly behavioral measures and further reveals the participants' ability to quickly suppress covert activations before they result in an overt movement. Following dopamine depletion, compared with a placebo condition, participants displayed comparable impulse activation but were less proficient at suppressing the interference from this activation. These results provide evidence that the dopamine system is directly involved in the suppression of maladaptive response impulses. PMID:25038871

Ramdani, Céline; Carbonnell, Laurence; Vidal, Franck; Béranger, Cyrille; Dagher, Alain; Hasbroucq, Thierry

2015-01-01

242

Determining aquifer parameters from the impulse response to pumping  

Science.gov (United States)

The impulse response of non-leaky and leaky confined aquifers is used to determine aquifer properties. The impulse response is determined by differentiating the response observed from a constant rate pumping test. A linearized form of the impulse response is then fitted using least-squares regression to determine values for transmissivity, storage coefficient, and leakance. This approach appears to be best suited for a preliminary analysis. Estimated values can then be refined or checked by calculating complete time-drawdown responses. Advantages of the impulse method include its simplicity and that there is no requirement for starting values.

Kelly, W. E.; Bogardi, I.

1993-04-01

243

Optoelectronic signal processing using finite impulse response neural networks  

Science.gov (United States)

This thesis investigates the use of finite impulse response neural network as the computational algorithm for efficient optoelectronic signal processing. The study begins with the analysis and development of different suitable algorithms, followed by the optoelectronic design of single-layer and multi-layer architectures, and it is concluded with the presentation of the results of a successful experimental implementation. First, finite impulse response adaptive filters and neural networks-the algorithmic building blocks-are introduced, followed by a description of finite impulse response neural networks. This introduction is followed by a historical background, describing early optoelectronic implementations of these algorithms. Next, different algorithms capable of temporal back-propagation are derived in detail, including a novel modification to the conventional algorithm, called delayed-feedback back- propagation. Based on these algorithms, different optoelectronic processors making use of adaptive volume holograms and three-dimensional optical processing are developed. Two single-layer architectures are presented: the input delay plane architecture and the output delay plane architecture. By combining them it is possible to implement both forward and backward propagation in two complementary multi-layer architectures: the first making use of the conventional temporal back-propagation and the second making use of delayed feedback back-propagation. Next, emphasis is given to a specific application: the processing of signals from adaptive antenna arrays. This research is initiated by computer simulations of different scenarios with multiple broadband signals and jammers, in planar and circular arrays, studying issues such as the effect of modulator non-linearities to the performance of the array, and the relation between the number of jammers and the final nulling depth. Two sets of simulations are presented: the first set applied to RF antenna arrays and the second set applied to an experimental implementation of a sonar adaptive array. Experimental results are presented for a single-layer optical processor making use of a scrolling spatial light modulator for representing the input signal and its delayed versions, photorefractive dynamic gratings for implementing the adaptive weights, differential heterodyning for bipolar signal representation, a phase- locked loop for controlling the optical path length, providing long term interferometric stabilization, and acousto-optic modulators for modulating the feedback error signal. Results for multiple beam-forming and jammer nulling are presented for planar and circular adaptive arrays. Finally, it is also shown how one can determine the position of the signal source from the images diffracted from the photorefractive hologram used to store the dynamic weights.

H. B. Xavier da Silveira, Paulo Eduardo

2001-08-01

244

Gyratonic pp waves and their impulsive limit  

Science.gov (United States)

We investigate a class of gravitational pp waves which represent the exterior vacuum field of spinning particles moving with the speed of light. Such exact spacetimes are described by the original Brinkmann form of the pp-wave metric including the often-neglected off-diagonal terms. We put emphasis on a clear physical and geometrical interpretation of these off-diagonal metric components. We explicitly analyze several new properties of these spacetimes associated with the spinning character of the source, such as rotational dragging of frames, geodesic deviation, impulsive limits and the corresponding behavior of geodesics.

Podolský, J.; Steinbauer, R.; Švarc, R.

2014-08-01

245

Controller reduction by preserving impulse response energy  

Science.gov (United States)

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.

Craig, Roy R., Jr.; Su, Tzu-Jeng

1989-01-01

246

Impulse Noise removal in Digital Images  

Directory of Open Access Journals (Sweden)

Full Text Available In this paper, we introduce a new class of filter, the modified spatial median filter (MSMF for the removal of impulse noise in digital images. The proposed filter is compared with four different filtering algorithms based on their ability to reconstruct noise-affected images. In-order to better appraise the noise cancellation behavior of our filter from the point of view of human perception, we perform edge detection using canny filter. Experimental results show that the filtering performance of the proposed approach is very satisfactory.

M.JayaManmadhaRao,

2010-10-01

247

The genetic correlation between procrastination and impulsivity.  

Science.gov (United States)

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. PMID:25431285

Loehlin, John C; Martin, Nicholas G

2014-12-01

248

Dynamical mechanical systems under random impulses  

CERN Document Server

The book presents the methods of analysis of dynamical mechanical systems subjected to stochastic excitations in form of random trains of impulses. This particular class of excitations is adequately characterized by stochastic point processes and behaviour of dynamical systems is governed by stochastic differential equations driven by point processes. Based on the methods of point processes the analytical techniques are devised to characterize the response of linear and nonlinear mechanical systems as the solutions of underlying stochastic differential equations. A number of example problems o

Iwankiewicz, R

1995-01-01

249

Transient Impulsive Giant Electronic Raman Redistribution  

CERN Document Server

Resonant Raman excitation by ultrafast vacuum ultraviolet laser pulses is a powerful means to study electron dynamics in molecules, but experiments must contend with linear background ionization: frequencies high enough to reach resonant core-valence transitions will usually ionize all occupied orbitals as well, and the ionization cross sections are usually dominant. Here we show that attosecond pulses can induce a new process, transient impulsive stimulated Raman scattering, which can overwhelm valence ionization. Calculations are performed for atomic sodium, but the principal is valid for many molecular systems. This approach opens the path for high fidelity multidimensional spectroscopy with attosecond pulses.

Miyabe, S

2014-01-01

250

CHECK AND CONTROL ELECTRONIC SYSTEM IN MAGNETIC-IMPULSE SETUP WITH MULTIPLE REPEATING OF DISCHARGE IMPULSES  

Directory of Open Access Journals (Sweden)

Full Text Available The modern microprocessor system controling the complex of electromagnetic flattening of vehicles is created in this work. Microprocessor system for control and check of magnetic-impulse setup meets the formulated conditions for the conversion on the other level of modern electro technical devices.

G. Kaljanov

2009-01-01

251

Evaluation of behavioral impulsivity and aggression tasks as endophenotypes for borderline personality disorder  

OpenAIRE

Borderline personality disorder (BPD) is marked by aggression and impulsive, often self-destructive behavior. Despite the severe risks associated with BPD, relatively little is known about the disorder’s etiology. Identification of genetic correlates (endophenotypes) of BPD would improve the prospects of targeted interventions for more homogeneous subsets of borderline patients characterized by specific genetic vulnerabilities. The current study evaluated behavioral measures of aggression a...

Mccloskey, Michael S.; New, Antonia S.; Siever, Larry J.; Goodman, Marianne; Koenigsberg, Harold W.; Flory, Janine D.; Coccaro, Emil F.

2009-01-01

252

Simulation Platform for Wireless Sensor Networks Based on Impulse Radio Ultra Wide Band  

OpenAIRE

Impulse Radio Ultra Wide Band (IR-UWB) is a promising technology to address Wireless Sensor Network (WSN) constraints. However, existing network simulation tools do not provide a complete WSN simulation architecture, with the IR-UWB specificities at the PHYsical (PHY) and the Medium Access Control (MAC) layers. In this paper, we propose a WSN simulation architecture based on the IR-UWB technique. At the PHY layer, we take into account the pulse collision by dealing with the ...

Berthe, Abdoulaye; Lecointre, Aubin; Dragomirescu, Daniela; Plana, Robert

2009-01-01

253

Different subtypes of impulsivity differentiate uncontrolled eating and dietary restraint.  

Science.gov (United States)

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. PMID:23702263

Leitch, Margaret A; Morgan, Michael J; Yeomans, Martin R

2013-10-01

254

An improved radial impulse turbine for OWC  

Energy Technology Data Exchange (ETDEWEB)

Traditionally, wells turbines have been widely used in OWC plants. However, an alternative has been studied over recent years: a self-rectifying turbine known as an impulse turbine. We are interested in the radial version of the impulse turbine, which was initially proposed by M. McCormick. Previous research was carried out using CFD (FLUENT {sup registered}), which aimed to improve knowledge of the local flow behavior and the prediction of the performance for this kind of turbine. This previous work was developed with a geometry taken from the literature, but now our goal is to develop a new geometry design with a better performance. To achieve this, we have redesigned the blade and vane profiles and improved the interaction between them by means of a new relation between their setting angles. Under sinusoidal flow conditions the new design improves the turbine efficiency by up to 5% more than the geometry proposed by Professor Setoguchi, in 2002. In this paper, the design criteria we have used is described, and the flow behavior and the performance of this new design are compared with the previous one. (author)

Pereiras, Bruno; Castro, Francisco; Rodriguez, Miguel A. [Energy Engineering and Fluid Mechanics Department, University of Valladolid, Paseo del cauce 59, 47011, Valladolid (Spain); Marjani, Abdelatif el [Labo. de Turbomachines, Ecole Mohammadia d' Ingenieurs (EMI), University of Mohammed V Agdal. Av Ibn Sina, B.P. 765 Agdal Rabat (Morocco)

2011-05-15

255

Pinning impulsive control algorithms for complex network  

Energy Technology Data Exchange (ETDEWEB)

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.

Sun, Wen [School of Information and Mathematics, Yangtze University, Jingzhou 434023 (China); Lü, Jinhu [Academy of Mathematics and Systems Science, Chinese Academy of Sciences, Beijing 100190 (China); Chen, Shihua [College of Mathematics and Statistics, Wuhan University, Wuhan 430072 (China); Yu, Xinghuo [School of Electrical and Computer Engineering, RMIT University, Melbourne VIC 3001 (Australia)

2014-03-15

256

Designing an electro-impulse de-icing system  

Science.gov (United States)

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.

Zumwalt, G. W.; Friedberg, R. A.

1986-01-01

257

Does oxygen delivery explain interindividual variation in forearm critical impulse?  

Science.gov (United States)

Within individuals, critical power appears sensitive to manipulations in O2 delivery. We asked whether interindividual differences in forearm O2 delivery might account for a majority of the interindividual differences in forearm critical force impulse (critical impulse), the force analog of critical power. Ten healthy men (24.6 ± 7.10 years) completed a maximal effort rhythmic handgrip exercise test (1 sec contraction-2 sec relaxation) for 10 min. The average of contraction impulses over the last 30 sec quantified critical impulse. Forearm brachial artery blood flow (FBF; echo and Doppler ultrasound) and mean arterial pressure (MAP; finger photoplethysmography) were measured continuously. O2 delivery (FBF arterial oxygen content (venous blood [hemoglobin] and oxygen saturation from pulse oximetry)) and forearm vascular conductance (FVC; FBF·MAP(-1)) were calculated. There was a wide range in O2 delivery (59.98-121.15 O2 mL·min(-1)) and critical impulse (381.5-584.8 N) across subjects. During maximal effort exercise, O2 delivery increased rapidly, plateauing well before the declining forearm impulse and explained most of the interindividual differences in critical impulse (r(2) = 0.85, P response (r(2) = 0.33, P impulse. Furthermore, individual differences in pressor response play an important role in determining differences in O2 delivery in addition to vasodilation. The mechanistic origins of this vasodilatory and pressor response heterogeneity across individuals remain to be determined. PMID:25413323

Kellawan, J Mikhail; Bentley, Robert F; Bravo, Michael F; Moynes, Jackie S; Tschakovsky, Michael E

2014-11-01

258

Asymptotic stability of competitive systems with delays and impulsive perturbations  

Science.gov (United States)

A general impulsive nonautonomous Lotka-Volterra system of integro-differential equations with infinite delay is considered. The impulses are realized at fixed moments of time. Sufficient conditions for uniform stability and asymptotic stability of solutions are investigated. The main results are obtained by using the comparison principle and the Lyapunov method.

Ahmad, Shair; Stamova, Ivanka M.

2007-10-01

259

Error Estimates for a Stochastic Impulse Control Problem  

International Nuclear Information System (INIS)

We obtain error bounds for monotone approximation schemes of a stochastic impulse control problem. This is an extension of the theory for error estimates for the Hamilton-Jacobi-Bellman equation. We obtain almost the same estimate on the rate of convergence as in the equation without impulsions

260

Impulsive X-ray radiation characteristics of solar flare footpoints  

Science.gov (United States)

46 solar flares showing 228 impulsive SXR brightenings have been investigated using Yohkoh data. For 18 flares we made a quantitative comparison between footpoints seen in soft and hard X-rays. We present evidence that in the flare impulsive phase chromospheric evaporation is driven mainly by low-energy non-thermal electrons.

Mrozek, T.; Tomczak, M.

261

Impulsivity, Coping, Stress, and Problem Gambling among University Students  

Science.gov (United States)

The authors investigated whether coping styles moderated the relationship between (a) impulsivity and stress and (b) stress and gambling behavior and tested whether impulsive persons who use avoidant or emotion-focused coping under high-stress conditions are most likely to gamble. Among 202 university student volunteers, 33% of men but only 3% of…

Lightsey, Owen Richard, Jr.; Hulsey, C. Duncan

2002-01-01

262

Asymptotic behavior of second-order impulsive differential equations  

Directory of Open Access Journals (Sweden)

Full Text Available In this article, we study the asymptotic behavior of all solutions of 2-th order nonlinear delay differential equation with impulses. Our main tools are impulsive differential inequalities and the Riccati transformation. We illustrate the results by an example.

Haifeng Liu

2011-02-01

263

Effects of Strategies Marketing of Collective Buying about Impulsive Behavior  

Directory of Open Access Journals (Sweden)

Full Text Available Brazil has the second largest e-commerce market in the world. One model used in this sector is "collective buying", a feature of which is impulse sales. Consumer behavior can be influenced by several factors, two of which are addressed in this article: the individual impulsivity of consumers and strategies of mix marketing. Impulsive buying is characterized by an unplanned purchase, i.e. the need to acquire the product arises just before the purchase. Consumers respond differently to mixed strategies depending on their degree of impulsivity. Thus, this article aims to analyze the efficacy of different marketing mix strategies for impulsive and non-impulsive consumer purchasing behavior. 137 participants were given a questionnaire containing the Buying Impulsiveness scale from Rook and Fisher (1995, and statements about the marketing strategies used by collective buying sites. Through a regression analysis, three strategies were found to relate more to impulsivity: search for products from well-known brands, search for deals with big discounts and confidence in receiving the product. For e-commerce and researchers, this study elucidates which strategies, from the consumer's perspective, effectively persuade purchasing behavior.

Suzi Elen Ferreira Dias

2014-08-01

264

GENERAL: Impulsive Control for Fractional-Order Chaotic Systems  

Science.gov (United States)

We propose an impulsive control scheme for fractional-order chaotic systems. Based on the Takagi-Sugeno (T-S) fuzzy model and linear matrix inequalities (LMIs), some sufficient conditions are given to stabilize the fractional-order chaotic system via impulsive control. Numerical simulation shows the effectiveness of this approach.

Zhong, Qi-Shui; Bao, Jing-Fu; Yu, Yong-Bin; Liao, Xiao-Feng

2008-08-01

265

Chaotic attitude control of satellite using impulsive control  

International Nuclear Information System (INIS)

Nowadays, attitude control systems of satellites demand better performance, resulting in the application of new advanced nonlinear control theory. In this paper, impulsive control is applied to a six-dimensional system which describes the attitude dynamics of a satellite subjected to deterministic external perturbations which induce chaotic motion when no control is affected. Several theorems on the stability of impulsive control systems are presented. These theorems are then used to find the conditions under which the chaotic systems can be asymptotically controlled to the origin by using impulsive control. Given the parameters of the chaotic system and the impulsive control law, an estimation of the upper bound of the impulse interval is given. Finally, we give some simulations results to visualize the effectiveness and feasibility of the proposed method.

266

Virtual Shopping and Impulse Purchasing Strengths and Weaknesses in Pakistan  

Directory of Open Access Journals (Sweden)

Full Text Available This research analyzed the perceptive of consumers doing online shopping and impulse purchasing. This study examined the behavior of thirty consumers who were asked to fill the questionnaire based on some close ended questions. The focus of this investigation was to discuss the strengths and Weaknesses of online shopping and impulse purchasing in developing country like Pakistan. Today consumers choose and buy things while sitting at home through internet and buy things impulsively. Do consumer in Pakistan are using Internet for shopping online? Do they make more impulse purchase on the Internet? Does online shopping save time? Do online shopping is more attractive or consumer feels lack of trust? Impacts of advertising are also discussed. We covered the virtual shopping weakness and strengths in our VSIPSWP (Virtual Shopping and Impulse Purchasing Strengths and Weaknesses in Pakistan Models.

Muhammad Ali Hussain

2011-11-01

267

Impulse Testing of Corporate-Fed Patch Array Antennas  

Science.gov (United States)

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

Chamberlain, Neil F.

2011-01-01

268

A systematic review of impulse control disorders in Parkinson's disease  

DEFF Research Database (Denmark)

Throughout the past decade it has been recognized that dopaminergic medication administered to remedy motor symptoms in Parkinson's disease is associated with an enhanced risk for impulse control disorders and related compulsive behaviors such as hobbyism, punding, and the dopamine dysregulation syndrome. These complications are relatively frequent, affecting 6-15.5% of patients, and they most often appear, or worsen, after initiation of dopaminergic therapy or dosage increase. Recently, impulse control disorders have also been associated with subthalamic nucleus deep brain stimulation. Here we present a systematic overview of literature published between 2000 and January 2013 reporting impulse control disorders in Parkinson's disease. We consider prevalence rates and discuss the functional neuroanatomy, the impact of dopamine-serotonin interactions, and the cognitive symptomatology associated with impulse control disorders in Parkinson's disease. Finally, perspectives for future research and management of impulse control disorders in Parkinson's disease are discussed.

Callesen, Mette Buhl; Scheel-Krüger, JØrgen

2013-01-01

269

Partial discharge characteristics and mechanism in voids at impulse voltages  

International Nuclear Information System (INIS)

Partial discharge (PD) characteristics and mechanism in artificial cavities in an epoxy plate have been investigated for different void dimensions and impulse voltage waveforms. A differential measurement system was developed in order to detect PD current pulses effectively. Experimental results showed that the 50% probability PD inception voltage (PDIV50) increases initially as the cavity diameter decreases at constant depth for double exponential impulses as well as oscillating impulses, but after aging, it becomes independent of the cavity diameter. Moreover, some distinctive characteristics of PD (e.g. main discharge and reverse discharge during the rise and fall phases of the applied voltage) were also investigated. The differences of the PD propagation and the mechanism between double exponential impulses and oscillating impulse were discussed

270

Second method of Lyapunov for stability of linear impulsive differential-difference equations with variable impulsive perturbations  

Directory of Open Access Journals (Sweden)

Full Text Available The present work is devoted to the study of stability of the zero solution to linear impulsive differential-difference equations with variable impulsive perturbations. With the aid of piecewise continuous auxiliary functions, which are generalizations of the classical Lyapunov's functions, sufficient conditions are found for the uniform stability and uniform asymptotical stability of the zero solution to equations under consideration.

D. D. Bainov

1998-01-01

271

When is "impulsiveness" not impulsive? The case of hyperactive children's cognitive style.  

Science.gov (United States)

On two computerized versions of the Matching Familiar Figures Test (MFFT; Kagan, Child Development, 36, 609-628, 1965) pervasively hyperactive and matched control children had to identify a target from among five similar foils. One version had a temporal structure similar to the manual MFFT and trial length was determined by response speed. Hyperactive children behaved in an "impulsive" manner; they responded more quickly and made more mistakes than controls. Despite this they completed each trial more quickly than controls by identifying the target. On the second version, the length of each trial was fixed at 45 seconds. Although both groups were equally "reflective", hyperactive children still made more mistakes. Implications of these results for research in impulse control in general and hyperactivity in particular are discussed. PMID:7806608

Sonuga-Barke, E J; Houlberg, K; Hall, M

1994-10-01

272

A spline-based approach for computing spatial impulse responses.  

Science.gov (United States)

Computer simulations are an essential tool for the design of phased-array ultrasonic imaging systems. FIELD II, which determines the two-way temporal response of a transducer at a point in space, is the current de facto standard for ultrasound simulation tools. However, the need often arises to obtain two-way spatial responses at a single point in time, a set of dimensions for which FIELD II is not well optimized. This paper describes an analytical approach for computing the two-way, far-field, spatial impulse response from rectangular transducer elements under arbitrary excitation. The described approach determines the response as the sum of polynomial functions, making computational implementation quite straightforward. The proposed algorithm, named DELFI, was implemented as a C routine under Matlab and results were compared to those obtained under similar conditions from the well-established FIELD II program. Under the specific conditions tested here, the proposed algorithm was approximately 142 times faster than FIELD II for computing spatial sensitivity functions with similar amounts of error. For temporal sensitivity functions with similar amounts of error, the proposed algorithm was about 1.7 times slower than FIELD II using rectangular elements and 19.2 times faster than FIELD II using triangular elements. DELFI is shown to be an attractive complement to FIELD II, especially when spatial responses are needed at a specific point in time. PMID:17523569

Ellis, Michael A; Guenther, Drake; Walker, William F

2007-05-01

273

Detecting Structural Failures Via Acoustic Impulse Responses  

Science.gov (United States)

Advanced method of acoustic pulse reflectivity testing developed for use in determining sizes and locations of failures within structures. Used to detect breaks in electrical transmission lines, detect faults in optical fibers, and determine mechanical properties of materials. In method, structure vibrationally excited with acoustic pulse (a "ping") at one location and acoustic response measured at same or different location. Measured acoustic response digitized, then processed by finite-impulse-response (FIR) filtering algorithm unique to method and based on acoustic-wave-propagation and -reflection properties of structure. Offers several advantages: does not require training, does not require prior knowledge of mathematical model of acoustic response of structure, enables detection and localization of multiple failures, and yields data on extent of damage at each location.

Bayard, David S.; Joshi, Sanjay S.

1995-01-01

274

Optimal Stochastic Impulse Control with Delayed Reaction  

International Nuclear Information System (INIS)

We study impulse control problems of jump diffusions with delayed reaction. This means that there is a delay ?>0 between the time when a decision for intervention is taken and the time when the intervention is actually carried out. We show that under certain conditions this problem can be transformed into a sequence of iterated no-delay optimal stopping problems and there is an explicit relation between the solutions of these two problems. The results are illustrated by an example where the problem is to find the optimal times to increase the production capacity of a firm, assuming that there are transaction costs with each new order and the increase takes place ? time units after the (irreversible) order has been placed

275

Investigation of gas discharge impulse image intensifiers  

CERN Document Server

The gas discharge impulse image intensifiers (GDIII) operated in the streamer mode are studied in this work. The GDIII has a resolution of 5-15 lines/cm and light amplification up to approx 10 sup 1 sup 0. The possibility to design a single-electron GDIII for RICH-detectors is considered. For this purpose the emission of photoelectrons in He, Ne, Ar, Xe, CO sub 2 , iC sub 4 H sub 1 sub 0 and their mixtures in the 50-760 Torr pressure range have been investigated. The best working gas for the GDIII is Ne+(approx 0.1%)iC sub 4 H sub 1 sub 0 mixture having an electron output factor up to 0.45.

Gushchin, E M; Timofeev, M K

1999-01-01

276

SAR impulse response with residual chirps.  

Energy Technology Data Exchange (ETDEWEB)

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.

Doerry, Armin Walter

2009-06-01

277

Impulsive ion acceleration in earth's outer magnetosphere  

International Nuclear Information System (INIS)

Considerable observational evidence is found that ions are accelerated to high energies in the outer magnetosphere during geomagnetic disturbances. The acceleration often appears to be quite impulsive causing temporally brief (10's of seconds), very intense bursts of ions in the distant plasma sheet as well as in the near-tail region. These ion bursts extend in energy from 10's of keV to over 1 MeV and are closely associated with substorm expansive phase onsets. Although the very energetic ions are not of dominant importance for magnetotail plasma dynamics, they serve as an important tracer population. Their absolute intensity and brief temporal appearance bespeaks a strong and rapid acceleration process in the near-tail, very probably involving large induced electric fields substantially greater than those associated with cross-tail potential drops. Subsequent to their impulsive acceleration, these ions are injected into the outer trapping regions forming ion ''drift echo'' events, as well as streaming tailward away from their acceleration site in the near-earth plasma sheet. Most auroral ion acceleration processes occur (or are greatly enhanced) during the time that these global magnetospheric events are occurring in the magnetotail. A qualitative model relating energetic ion populations to near-tail magnetic reconnection at substorm onset followed by global redistribution is quite successful in explaining the primary observational features. Recent measurements of the elemental composition and charge-states have proven valuable for showing the source (solar wind or ionosphere) of the original plasma population from which the ions were accelerated

278

Determination of poles and zeroes using SAVOSIM for digital impulse-shaping  

International Nuclear Information System (INIS)

Digital impulse pulse-shaping can be used to correct the pile-up for pulse-height (Energy) analyzer because of its fast processing speed. In this initial work on digital impulse pulse-shaping, a study is made on the input signals obtained from combination of preamplifier and prefilter of nuclear instrumentation with specific and general transfer function. Three types of pulses that are commonly produced by a nuclear detection preamplifier and prefilter are used for this application. For the determination of zeros and poles in z-transform, the summation of absolute value of output signal is minimum (SAVOSIM) method is used. Simulations for this type of signal are carried out using the MATLAB software and the TMS320C6701 evaluation module and the results are presented in this paper. Initial results show that the method can be expanded to design and develop for a nuclear spectroscopy based on digital signal processor. (Author)

279

Impulsivity and control of inhibition in Benign Focal Childhood Epilepsy (BFCE).  

Science.gov (United States)

Childhood epilepsy represents abnormal brain functioning and may affect cognitive functions that depend on the late development of the frontal lobes. This study addresses the possible consequences of benign epilepsy on frontal functions, specifically action regulation and inhibition in the absence of explicit frontal neurological signs. Thirteen children (8 males; 6-12 years old) with benign epilepsy were matched to 13 controls. They performed tasks designed to measure impulsivity and control of inhibition: CPT, Stop Signal Paradigm, Stroop test, and Matching Familiar Figures Test (MFFT). Children with epilepsy made more errors on the MFFT (p test (p < .01), and had a longer response time to the Stop Signal (p < .05) than controls, with no differences on nonexecutive functions measures. Thus, children with benign epilepsy have a deficit on some measures of impulsivity and inhibition, which may reflect poor frontal lobe functioning. PMID:10857669

Chevalier, H; Metz-Lutz, M N; Segalowitz, S J

2000-01-01

280

A simplified approach to uncertainty quantification for orbits in impulsive deflection scenarios  

Science.gov (United States)

For the majority of near-Earth Asteroid (NEA) impact scenarios, optimal deflection strategies use a massive impactor or a nuclear explosive, either of which produce an impulsive change to the orbit of the object. However, uncertainties regarding the object composition and the efficiency of the deflection event lead to a non-negligible uncertainty in the deflection delta-velocity. Propagating this uncertainty through the resulting orbit will create a positional uncertainty envelope at the original impact epoch. We calculate a simplified analytic evolution for impulsively deflected NEAs and perform a full propagation of uncertainties that is nonlinear in the deflection delta-velocity vector. This provides an understanding of both the optimal deflection velocities needed for a given scenario, as well as the resulting positional uncertainty and corresponding residual impact probability. Confidence of a successful deflection attempt as a function of launch opportunities is also discussed for a specific case.

Howley, Kirsten; Wasem, Joseph

2014-11-01

281

Comparison among various methods of assessment of impulsiveness.  

Science.gov (United States)

The current confused status of the research on impulsivity may be attributed to the lack of precise definitions, the reliance of most operationalizations on a single index, and inconsistency among different measures of the construct. Empirical measurements of impulsivity by self-reports, rating scales, or performance tasks suggest that the instruments employed measure aspects that have very little in common, a finding that throws serious doubts on the validity of the construct and implies a need for further research. To clarify this topic, we applied four different measures of impulsivity to 46 7th-grade (12 to 13 years old) schoolchildren. The children were rated by their teachers on an impulsivity behavior scale and were administered Kagan's Matching Familiar Figures Test, Version MFF-20, and two self-report forms, the Eysenck Impulsiveness Questionnaire, and the Barratt Impulsiveness Scale. Although the results confirmed the lack of convergence among these measures, high latencies on matching were associated with the cognitive aspect of the self-report scales. Treating impulsivity as a multidimensional construct is discussed. PMID:8247681

Carrillo-de-la-Peña, M T; Otero, J M; Romero, E

1993-10-01

282

Stability of Impulsive Differential Equation with any Time Delay  

Directory of Open Access Journals (Sweden)

Full Text Available In this paper, the stability of general impulsive retarded functional differential equations with any time delay has been considered. Many evolution processes are characterized by the fact that at certain moments of time they experience a change of state abruptly. Consequently, it is natural to assume that these perturbations act instantaneously, that is, in the form of impulses. Impulsive differential equations, that is, differential equations involving impulse effects, are a natural description of observed evolution phenomena of several real world problems. Impulsive control which based on impulsive differential equations has attracted the interest of many researchers recently. The method of Lyapunov functions and Razumikhin technique have been widely applied to stability analysis of various delay differential equation. When Lyapunov functions are used, it becomes necessary to choose an appropriate minimal class of functionals relative to which the derivative of the Lyapunov function is estimated. This approach is known as the Lyapunov–Razumikhin technique. When Lyapunov functionals are used the corresponding derivative can be estimated without demanding minimal classes of functional. By using Lyapunov functions and analysis technique along with Razumikhin technique, some results for the uniform stability of such impulsive differential equations have been derived. The obtained results extend and generalize some results existing in the literature.

Sanjay K. Srivastava

2013-03-01

283

Time Domain Modeling of Powerline Impulsive Noise at Its Source  

Directory of Open Access Journals (Sweden)

Full Text Available Noise characteristics of an indoor power line network strongly influence the link capability to achieve high data rates. The appliances shared with PLC modems in the same powerline network generate different types of noises, among them the impulsive noises are the main source of interference resulting in signal distortions and bit errors during data transmission. With regard to impulsive noise many models were proposed in the literature and shared the same impulsive noise definition: “unpredictable noises measured in the receiver side”. Authors are, consequently, confronted to model thousands of impulsive noises whose plurality would very likely come from the diversity of paths that the original impulsive noise took. In this paper, an innovative modelling approach is applied to impulsive noises which are studied here directly at their sources. Noise at receiver would be simply the noise model at source convolved by powerline channel block. In the new analytical model, the impulsive noise at source is described by a succession of short pulses, each modeled by a phase-shifted Gaussian. Noises at source are classified into 6 different classes [1], and a noise generator is established for each class.

Hassina Chaouche

2011-09-01

284

Impulse-response analysis of the market share attraction model  

OpenAIRE

We propose a simulation-based technique to calculate impulse-response functions and their confidence intervals in a market share attraction model [MCI]. As an MCI model implies a reduced form model for the logs of relative market shares, simulation techniques have to be used to obtain the impulse-responses for the levels of the market shares. We apply the technique to an MCI model for a five-brand detergent market. We illustrate how impulse-response functions can help to interpret the est...

Fok, D.; Franses, Ph H. B. F.

1999-01-01

285

Impulse control in Kalman-like filtering problems  

Directory of Open Access Journals (Sweden)

Full Text Available This paper develops the impulse control approach to the observation process in Kalman-like filtering problems, which is based on impulsive modeling of the transition matrix in an observation equation. The impulse control generates the jumps of the estimate variance from its current position down to zero and, as a result, enables us to obtain the filtering equations for the Kalman estimate with zero variance for all post-jump time moments. The filtering equations for the estimates with zero variances are obtained in the conventional linear filtering problem and in the case of scalar nonlinear state and nonlinear observation equations.

Michael V. Basin

1998-01-01

286

Impulsive Alfven coupling between the magnetosphere and ionosphere  

International Nuclear Information System (INIS)

Basic properties of the impulsive Alfven interaction between the magnetosphere and ionosphere have been studied by means of a three-dimensional self-consistent simulation of the coupled magnetosphere and ionosphere system. It is found that the duration time of an impulsive perturbation at the magnetospheric equator, the latitudinal distribution of the Alfven propagation time along the field lines, and the ratio between the magnetospheric impedance and the ionospheric resistance is the main key factors that determine the propagation dynamics and the ionospheric responses for an impulsive MHD perturbation in the magnetosphere. (author)

287

Impulsive Cluster Synchronization in Community Network with Nonidentical Nodes  

International Nuclear Information System (INIS)

In this paper, cluster synchronization in community network with nonidentical nodes and impulsive effects is investigated. Community networks with two kinds of topological structure are investigated. Positive weighted network is considered first and external pinning controllers are designed for achieving cluster synchronization. Cooperative and competitive network under some assumptions is investigated as well and can achieve cluster synchronization with only impulsive controllers. Based on the stability analysis of impulsive differential equation and the Lyapunov stability theory, several simple and useful synchronization criteria are derived. Finally, numerical simulations are provided to verify the effectiveness of the derived results.

288

Pediatric Asthma and Problems in Attention, Concentration, and Impulsivity  

Science.gov (United States)

Rationale This study assesses the relationships between ADHD symptoms, specific family asthma management domains, and pediatric asthma morbidity. Methods Participants were 110 children with asthma and a respective parent (ages 7-17, X = 11.6 years, 25% ethnic/racial minority). Parents completed measures of asthma morbidity and report of child ADHD symptoms. Children completed measures of attention, concentration, and impulsivity. Families participated in the Family Asthma Management System Scale (FAMSS) interview to assess the effectiveness of eight features of asthma management. Results Parent report of ADHD symptoms and poor child performance on a computerized task of sustained visual attention were associated with asthma morbidity. Paper and pencil tasks of visual attention, and an index of auditory attention, were not related to asthma morbidity. Modest associations were found between parent report of ADHD symptoms, child performance-based indicators of attention and concentration, and features of family asthma management, although not across all measures. The family response to asthma partially mediated the relationship between ADHD symptoms and morbidity. Conclusions ADHD symptoms are modestly associated with difficulties in family asthma management. PMID:19198669

McQuaid, Elizabeth L.; Weiss-Laxer, Nomi; Kopel, Sheryl J.; Mitchell, Daphne Koinis; Nassau, Jack H.; Wamboldt, Marianne Z.; Klein, Robert B.; Fritz, Gregory K.

2008-01-01

289

From gene to brain to behavior: schizophrenia-associated variation in AMBRA1 alters impulsivity-related traits.  

Science.gov (United States)

Recently, genome-wide association between schizophrenia and an intronic variant in AMBRA1 (rs11819869) was reported. Additionally, in a reverse genetic approach in adult healthy subjects, risk allele carriers showed a higher medial prefrontal cortex blood oxygen level-dependent (BOLD) response during a flanker task examining motor inhibition as an aspect of impulsivity. To test whether this finding can be expanded to further aspects of impulsivity, we analysed the effects of the rs11819869 genotype on impulsivity-related traits on a behavioral, temperament and neural level in a large sample of healthy adolescents. We consider this reverse genetic approach specifically suited for use in a healthy adolescent sample, as these individuals comprise those who will eventually develop mental disorders in which impulsivity is implicated. Healthy adolescents from the IMAGEN study were included in the neuropsychological analysis (n = 848) and a functional magnetic resonance imaging (fMRI) task (n = 512). Various aspects of impulsivity were assessed using the Temperament and Character Inventory-Revised, the Substance Use Risk Profile Scale, the Cambridge Cognition Neuropsychological Test Automated Battery, and the Stop Signal Task (SST) in the fMRI paradigm. On a behavioral level, increased delay aversion was observed in risk allele carriers. Furthermore, risk allele carriers showed a higher BOLD response in an orbito-frontal target region during the SST, which declined to trend status after Family Wise Error correction. Our findings support the hypothesis that the schizophrenia-related risk variant of rs11819869 is involved in various aspects of impulsivity, and that this involvement occurs on a behavioral as well as an imaging genetics level. PMID:23551272

Heinrich, Angela; Nees, Frauke; Lourdusamy, Anbarasu; Tzschoppe, Jelka; Meier, Sandra; Vollstädt-Klein, Sabine; Fauth-Bühler, Mira; Steiner, Sabina; Bach, Christiane; Poustka, Luise; Banaschewski, Tobias; Barker, Gareth J; Büchel, Christian; Conrod, Patricia J; Garavan, Hugh; Gallinat, Jürgen; Heinz, Andreas; Ittermann, Bernd; Loth, Eva; Mann, Karl; Artiges, Eric; Paus, Tomáš; Lawrence, Claire; Pausova, Zdenka; Smolka, Michael N; Ströhle, Andreas; Struve, Maren; Witt, Stephanie H; Schumann, Gunter; Flor, Herta; Rietschel, Marcella

2013-09-01

290

Summer-winter hemisphere asymmetry of the preliminary reverse impulse of geomagnetic storm sudden commencements at midlatitudes  

Science.gov (United States)

We present event-specific observational evidence for the prevalence of a summer-winter hemisphere asymmetry of the preliminary reverse impulse (PRI) of geomagnetic storm sudden commencements (SSCs) at midlatitudes of the local afternoon sector. The evidence is culled from the archived 10-s resolution data of midlatitude stations (geomagnetic latitude 23-46°) of the MM 210 magnetometer network. The hemisphere asymmetry is characterized by a larger peak amplitude of PRI in the summer hemisphere than in the winter hemisphere, and this feature is more prominently seen in the December solstice compared to the June solstice. In the December solstice SSC event, the amplitude of the preliminary reverse impulse, PRI (4.8 nT) at BRV (geomagnetic latitude 36.6°S) in the summer hemisphere is larger by a factor of 6 compared to that at MSR (geomagnetic latitude 37.6°N) in the winter hemisphere. The asymmetry is also apparent at lower latitudes: while the PRI assumed an amplitude of 3.7 nT at LEM (geomagnetic latitude 34.1°S), it is barely discernible at ONW (geomagnetic latitude 31.6°N) in the winter hemisphere. In the June solstice event, the PRI amplitude at RIK (geomagnetic latitude 34.7°N) in the summer hemisphere is higher by a factor of 3.44 compared to that at LEM (geomagnetic latitude 34.1°S) in the winter hemisphere. A similar behavior is also apparent in the equinox event though the hemisphere asymmetry of the preliminary reverse impulse (PRI) here is of moderate strength. In all the SSC events studied, the main impulse (MI) amplitude also exhibited the well-known summer-winter asymmetry, but the hemisphere asymmetry is more prominent with the preliminary reverse impulse (PRI) than with the main impulse (MI). Physical processes that could possibly account for the hemisphere asymmetry evidenced of the afternoon PRI at midlatitudes are discussed.

Sastri, J. H.; Yumoto, K.; Rao, J. V. S. V.; Ikeda, A.

2008-05-01

291

The behaviour of geodesics in constant-curvature spacetimes with expanding impulsive gravitational waves  

International Nuclear Information System (INIS)

Motion of free test particles in spacetimes of constant curvature with an expanding impulsive gravitational wave is completely described. Explicit formulae which identify the particle positions and velocities 'in front of' and 'behind' the impulse are derived for a general impulse of this type. As a particular example, the effect of spherical impulsive wave generated by a snapped cosmic string is analyzed and visualized.

292

Patterns of cortical thickness associated with impulse control disorders in Parkinson's disease.  

Science.gov (United States)

Previous functional neuroimaging studies in Parkinson's disease (PD) patients with impulse control disorders (ICDs) demonstrated dysfunction of the reward network, although the extent of anatomical changes is unclear. The aim of this study was to measure brain cortical thickness and subcortical volumes, and to assess their relationship with presence and severity of symptoms, in PD patients with and without ICDs. We studied 110 PD patients (N?=?58 with ICDs) and 33 healthy controls (all negative for ICDs) who underwent an extensive neurological, neuropsychological, and behavioral assessment as well as structural 1.5 Tesla magnetic resonance imaging (MRI). Between-group differences in brain cortical thickness and subcortical volumes, assessed with the FreeSurfer 5.1 tool, were analyzed. In patients with ICDs, we found significant cortical thinning in fronto-striatal circuitry, specifically in the right superior orbitofrontal, left rostral middle frontal, bilateral caudal middle frontal region, and corpus callosum, as well as volume reduction in the right accumbens and increase in the left amygdala. Finally, we observed a positive association relationship between severity of impulsive symptoms and left rostral middle frontal, inferior parietal, and supramarginal areas. These results support the involvement of both reward and response inhibition networks in PD patients with ICDs. Moreover, their severity is associated with alterations in brain regions linked with reward and top-down control networks. Increased understanding of the mechanisms underlying impulsive and compulsive behaviors might help improve therapeutic strategies for these important disorders. © 2015 International Parkinson and Movement Disorder Society. PMID:25649923

Biundo, Roberta; Weis, Luca; Facchini, Silvia; Formento-Dojot, Patrizia; Vallelunga, Annamaria; Pilleri, Manuela; Weintraub, Daniel; Antonini, Angelo

2015-04-15

293

Electro-impulse de-icing - A status report  

Science.gov (United States)

The advantages and disadvantages of the Electro-Impulse De-Icing (EIDI) system are examined. The design and operation of the EIDI are described. The effect of repeated impulsive loads on the structure and skin of the aircraft surface is investigated. It is observed that the wing skin directly over the coil receives the greatest stresses. Data from the testing of metal leading edges reveal that after 11,500 impulses cracks appear in the sheet brackets attaching the ribs to the coil beams. The composite leading edge was evaluated for fatigue, and after 20,000 impulses no cracks were detected. The advantages of the band-aid coil mount are discussed.

Zumwalt, G. W.

1988-01-01

294

Numerical analysis on acoustic impulse response for watermelon  

International Nuclear Information System (INIS)

In this study, we conducted both analysis on impact pulse signal and acoustic impulse response method using numerical analysistic finite element method. Considering its velocity, density, Young's Modulus, and Poisson's Ratio, we extracted featured parameters and compared both results of analysis on impact pulse signal and numerical analysis on acoustic impulse response then we found the feature of generated acoustic sound signal by way of numerical analysis varying featured parameters and consequently intended to extract feature indices influenced on its internal maturity through analysis of acoustic impulse response. As we analyzed impact pulse signal and extracted featured parameters concerned with evaluation of its ripeness, we found the plausibility of progress on nondestructive evaluation of ripeness and adoption of numerical analysis on acoustic impulse response.

295

Electrical Sterilization of Juice by Discharged HV Impulse Waveform  

Directory of Open Access Journals (Sweden)

Full Text Available In the sterilization system by using HV impulse waveform, apple juice was sterilized with HV discharged oscillatory decay waveform. The optimal condition of impulse waveform for electrical sterilization has presented the excellent condition at 40kV cm?1, 4mH and over. The characteristics of this waveform shows oscillatory decay waveform with multiple pulses. And this impulse waveform was more effective to kill S. Cervisiae than exponential decay waveform. S. Cervisiae to become musty and sour for apple juice was used as the sample. This apple juice has good effect of electrical sterilization because of higher conductivity than water. Therefore this experiment can be treated sterilization without loss of vitamin C and original taste or perfume to apple juice. As a result, it is found that apple juice can be sterilized on 40kVcm?1, 4mH and over by using our designed HV impulse sterilizer.

Hee K. Lee

2006-01-01

296

Pinning impulsive synchronization of complex-variable dynamical network  

Science.gov (United States)

In this paper, pinning combining with impulsive control scheme is adopted to investigate the synchronization of complex-variable dynamical network. Based on the Lyapunov function method and mathematical analysis technique, sufficient conditions for achieving synchronization is first analytically derived. This result extends the condition derived for real-variable dynamical network to complex-variable network. Further, adaptive strategy is adopted to relax the restrictions on the impulsive intervals and reduce the control cost. Noticeably, the proposed adaptive pinning impulsive control scheme is universal for different dynamical networks to some extent. The impulsive instants are chosen by solving a series of maximum problems subject to the derived conditions. Several numerical simulations are performed to illustrate the effectiveness and correctness of the derived theoretical results.

Wu, Zhaoyan; Liu, Danfeng; Ye, Qingling

2015-01-01

297

On second order impulsive functional differential equations in Banach spaces  

Directory of Open Access Journals (Sweden)

Full Text Available In this paper, a fixed point theorem due to Schaefer is used to investigate the existence of solutions for second order impulsive functional differential equations in Banach spaces.

M. Benchohra

2002-01-01

298

Gigabit impulse radio UWB signal generation and fiber transmission  

DEFF Research Database (Denmark)

We demonstrate 3.125 Gb/s photonic impulse radio UWB generation using an uncooled distributed feedback laser. After 50km fiber transmission the signal is recovered without errors using a digital signal processing receiver.

Rodes Lopez, Roberto; Gibbon, Timothy Braidwood

299

FPGA IMPLEMENTATION AND ANALYSIS OF IMPULSE NOISE REDUCTION IN IMAGES  

Directory of Open Access Journals (Sweden)

Full Text Available The images are affected by random valued impulse noises during the image capturing and processing stages. In this study, an efficient, high performance and low hardware utilized impulse noise reduction algorithm is presented. This methodology determines the optimum direction pixels through the estimation of standard deviation. The edges in the images are preserved during the process of impulse noise detection and removal stage. The hardware architecture for this design is proposed and its performance is analyzed with different FPGA Processors in terms of slices, LUTs and power consumption. The proposed hardware architecture consumes 1728 gates and power consumption of 159.95 mW. The main motivation behind this research is to design low power impulse noise detection architecture and its real time implementations.

P. Thirumurugan

2014-01-01

300

High power impulse magnetron sputtering discharge  

Energy Technology Data Exchange (ETDEWEB)

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.

Gudmundsson, J. T.; Brenning, N.; Lundin, D.; Helmersson, U. [University of Michigan--Shanghai Jiao Tong University Joint Institute, Shanghai Jiao Tong University, 800 Dong Chuan Road, Shanghai 200240 (China) and Science Institute, University of Iceland, Dunhaga 3, IS-107 Reykjavik (Iceland); Division of Space and Plasma Physics, School of Electrical Engineering, Royal Institute of Technology, SE-100 44, Stockholm (Sweden); Plasma and Coatings Division, IFM-Materials Physics, Linkoeping University, SE-581 83, Linkoeping (Sweden)

2012-05-15

301

Examining impulse-variability in overarm throwing.  

Science.gov (United States)

The purpose of this study was to examine variability in overarm throwing velocity and spatial output error at various percentages of maximum to test the prediction of an inverted-U function as predicted by impulse-variability theory and a speed-accuracy trade-off as predicted by Fitts' Law Thirty subjects (16 skilled, 14 unskilled) were instructed to throw a tennis ball at seven percentages of their maximum velocity (40-100%) in random order (9 trials per condition) at a target 30 feet away. Throwing velocity was measured with a radar gun and interpreted as an index of overall systemic power output. Within-subject throwing velocity variability was examined using within-subjects repeated-measures ANOVAs (7 repeated conditions) with built-in polynomial contrasts. Spatial error was analyzed using mixed model regression. Results indicated a quadratic fit with variability in throwing velocity increasing from 40% up to 60%, where it peaked, and then decreasing at each subsequent interval to maximum (p function in overarm throwing velocity variability as both skilled and unskilled subjects approach maximum effort. However, these data do not support the notion of a speed-accuracy trade-off. The consistent demonstration of an inverted-U function associated with systemic power output variability indicates an enhanced capability to regulate aspects of force production and relative timing between segments as individuals approach maximum effort, even in a complex ballistic skill. PMID:22402218

Urbin, M A; Stodden, David; Boros, Rhonda; Shannon, David

2012-01-01

302

Generalized impulse response analysis: General or Extreme?  

Scientific Electronic Library Online (English)

Full Text Available Esta nota analiza la limitación de utilizar la función generalizada de impulso-respuesta (FGIR) de los modelos autoregresivos VAR (Pesaran y Shin, 1998). El FGIR es invariante al orden del rezago de las variables asociadas al modelo VAR . De hecho, el FGIR produce un conjunto de funciones respuestas [...] con base a supuestos de identificación extremos que se contradicen entre ellos, a menos que la matriz de covarianza sea diagonal. Con la ayuda de ejemplos empíricos, la presente nota demuestra que el FGIR puede generar inferencias incorrectas. Abstract in english This note discusses a pitfall of using the generalized impulse response function (GIRF) in vector autoregressive (VAR) models (Pesaran and Shin, 1998). The GIRF is general because it is invariant to the ordering of the variables in the VAR. The GIRF, in fact, is extreme because it yields a set of re [...] sponse functions that are based on extreme identifying assumptions that contradict each other, unless the covariance matrix is diagonal. With a help of empirical examples, the present note demonstrates that the GIRF may yield quite misleading economic inferences.

Hyeongwoo, Kim.

2013-12-01

303

Reactive high power impulse magnetron sputtering  

Science.gov (United States)

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

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

2012-10-01

304

Adiabatic heating in impulsive solar flares  

Science.gov (United States)

A study is made of adiabatic heating in two impulsive solar flares on the basis of dynamic X-ray spectra in the 28-254 keV range, H-alpha, microwave, and meter-wave radio observations. It is found that the X-ray spectra of the events are like those of thermal bremsstrahlung from single-temperature plasmas in the 10-60 keV range if photospheric albedo is taken into account. The temperature-emission correlation indicates adiabatic compression followed by adiabatic expansion and that the electron distribution remains isotropic. H-alpha data suggest compressive energy transfer. The projected areas and volumes of the flares are estimated assuming that X-ray and microwave emissions are produced in a single thermal plasma. Electron densities of about 10 to the 9th/cu cm are found for homogeneous, spherically symmetric sources. It is noted that the strong self-absorption of hot-plasma gyrosynchrotron radiation reveals low magnetic field strengths.

Maetzler, C.; Bai, T.; Crannell, C. J.; Frost, K. J.

1978-01-01

305

Impulsivity and Attention Deficit-Hyperactivity Disorder: Subtype Classification Using the UPPS Impulsive Behavior Scale  

OpenAIRE

This study examined the classification accuracy of the UPPS Impulsive Behavior Scale (UPPS) in discriminating several attention deficit/hyperactivity disorder (ADHD) subtypes, including predominantly inattentive type (ADHD/I), combined type (ADHD/C), and combined type with behavioral problems (ADHD/ODD), between each other and a non-ADHD control group using logistic regression analyses. The sample consisted of 88 children ranging in age from 9.0 years to 12.8 years, with a mean of 10.9 years....

Miller, Drew J.; Derefinko, Karen J.; Lynam, Donald R.; Milich, Richard; Fillmore, Mark T.

2010-01-01

306

Impulse response function analysis of pore pressure in earthdams  

OpenAIRE

Effective control of dam safety requires that the measured pore-pressure data be interpreted in the shortest possible time following the readings. Direct resolution based on partial differential equations are not appropriate. We present a relevant formalism for analysing pore-pressure monitoring data: the Impulse Response Function Analysis (IRFA) method. The model based on approximations for the impulse response of the dam gives the variations in the pore-pressure measurement resulting from c...

Radzicki, Krzysztof; Bonelli, Stephane

2007-01-01

307

Confidence bands for impulse responses: Bonferroni versus Wald  

OpenAIRE

In impulse response analysis estimation uncertainty is typically displayed by constructing bands around estimated impulse response functions. These bands may be based on frequentist or Bayesian methods. If they are based on the joint distribution in the Bayesian framework or the joint asymptotic distribution possibly constructed with bootstrap methods in the frequentist framework often individual confidence intervals or credibility sets are simply connected to obtain the bands. Such bands are...

Winker, Peter; Helmut, Lu?tkepohl; Staszewska-bystrova, Anna

2014-01-01

308

THE IMPULSE RESPONSE FUNCTION ANALYSIS OF PORE PRESSURES MONITORING DATA  

OpenAIRE

Effective control of dam safety requires that the measured pore-pressure data be interpreted in the shortest possible time following the readings. Direct resolution based on partial differential equations are not appropriate. We present a relevant formalism for analysing pore-pressure monitoring data: the Impulse Response Function Analysis (IRFA) method. The model based on approximations for the impulse response of the dam gives the variations in the pore-pressure measurement resulting from c...

Bonelli, Stephane; Radzicki, Krzysztof

2007-01-01

309

A new approach to calculating spatial impulse responses  

OpenAIRE

Using linear acoustics the emitted and scattered ultrasound field can be found by using spatial impulse responses as developed by Tupholme (1969) and Stepanishen (1971). The impulse response is calculated by the Rayleigh integral by summing the spherical waves emitted from all of the aperture surface. The evaluation of the integral is cumbersome and quite involved for different aperture geometries. This paper re-investigates the problem and shows that the field can be found from the crossings...

Jensen, Jørgen Arendt

1997-01-01

310

Neural mechanisms of impulse control in sexually risky adolescents  

OpenAIRE

The consequences of risky sexual behavior are of public concern. Adolescents contribute disproportionately to negative consequences of risky sexual behavior. However, no research has examined the neural correlates of impulse control and real-world engagement in risky sexual behavior in this population. The aim of the present study was to examine this question. Twenty sexually active adolescents performed an impulse control task during a functional magnetic resonance imaging (fMRI) scan and ri...

Goldenberg, Diane; Telzer, Eva H.; Lieberman, Matthew D.; Fuligni, Andrew; Galva?n, Adriana

2013-01-01

311

Model Predictive Control based on Finite Impulse Response Models  

OpenAIRE

We develop a regularized l2 finite impulse response (FIR) predictive controller with input and input-rate constraints. Feedback is based on a simple constant output disturbance filter. The performance of the predictive controller in the face of plant-model mismatch is investigated by simulations and related to the uncertainty of the impulse response coefficients. The simulations can be used to benchmark l2 MPC against FIR based robust MPC as well as to estimate the maximum performance improve...

Prasath, Guru; Jørgensen, John Bagterp

2008-01-01

312

Interactive effects of drinking history and impulsivity on college drinking  

OpenAIRE

The transition from adolescence into emerging adulthood is a critical developmental period for changes in alcohol use and drinking related problems. Prior research has identified a number of distinct developmental alcohol use trajectories, which appear to be differentially related to young adult drinking outcomes. Another correlate of alcohol use in early adulthood is impulsivity. The primary aim of this study was to examine the moderating role of impulsivity in the relation between patterns ...

Adams, Zachary W.; Milich, Richard; Lynam, Donald R.; Charnigo, Richard J.

2013-01-01

313

Neurogenetics and Epigenetics in Impulsive Behaviour: Impact on Reward Circuitry  

OpenAIRE

Adverse, unfavourable life conditions, particularly during early life stages and infancy, can lead to epigenetic regulation of genes involved in stress-response, behavioral disinhibition, and cognitive-emotional systems. Over time, the ultimate final outcome can be expressed through behaviors bedeviled by problems with impulse control, such as eating disorders, alcoholism, and indiscriminate social behavior. While many reward gene polymorphisms are involved in impulsive behaviors, a polymorph...

Archer, Trevor; Oscar-berman, Marlene; Blum, Kenneth; Gold, Mark

2012-01-01

314

Dopamine and Impulse Control Disorders in Parkinson’s Disease  

OpenAIRE

There is an increasing awareness that impulse control disorders (ICDs), including compulsive gambling, buying, sexual behavior, and eating, can occur as a complication of Parkinson’s disease (PD). In addition, other impulsive or compulsive disorders have been reported to occur, including dopamine dysregulation syndrome (DDS) and punding. Case reporting and prospective studies have reported an association between ICDs and the use of dopamine agonists (DAs), particularly at greater dosages, w...

Weintraub, Daniel

2008-01-01

315

Lyapunov stability of closed sets in impulsive semidynamical systems  

Directory of Open Access Journals (Sweden)

Full Text Available In this article, we consider impulsive semidynamical systems, defined in a metric space, with impulse effects at variable times. Converse-type theorems are included in our results giving necessary and sufficient conditions for various types of stability of closed subsets of the metric space. These results are achieved by means of Lyapunov functionals which indicate how the solutions behave when entering a "stable" set.

Everaldo M. Bonotto

2010-06-01

316

Lyapunov stability of closed sets in impulsive semidynamical systems  

OpenAIRE

In this article, we consider impulsive semidynamical systems, defined in a metric space, with impulse effects at variable times. Converse-type theorems are included in our results giving necessary and sufficient conditions for various types of stability of closed subsets of the metric space. These results are achieved by means of Lyapunov functionals which indicate how the solutions behave when entering a "stable" set.

Bonotto, Everaldo M.; Grulha Jr, Nivaldo G.

2010-01-01

317

Impulsive Pressurization of Neuronal Cells for Traumatic Brain Injury Study  

OpenAIRE

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 insp...

Nienaber, Matthew; Lee, Jeong Soon; Feng, Ruqiang; Lim, Jung Yul

2011-01-01

318

Manipulation of plasma grating by impulsive molecular alignment  

International Nuclear Information System (INIS)

We experimentally demonstrated that multiphoton-ionization-induced plasma grating in air could be precisely manipulated by impulsive molecular alignment. In the linear region, the impulsively aligned molecules modulated the diffraction efficiency of the plasma grating for a time-delayed femtosecond laser pulse. In the nonlinear region, the third harmonic generation from the plasma grating was either enhanced or suppressed by following the alignment of the molecules

319

The impulsive X-ray response in flare footpoints  

Science.gov (United States)

The impulsive phase of many solar flares well-observed by Yohkoh has been investigated using images from the SXT and HXT telescopes. A response to nonthermal electron beams in the individual flare footpoint has been localized and measured. Morphological features such as soft X-ray impulsive brightening and a hard X-ray footpoint emission source have been considered. A correlation between these features has been studied and their dependence on the energy spectrum of nonthermal electron beams has been discussed.

Mrozek, T.; Tomczak, M.

2002-12-01

320

Heritability and Longitudinal Stability of Impulsivity in Adolescence  

OpenAIRE

Impulsivity is a multifaceted personality construct that plays an important role throughout the lifespan in psychopathological disorders involving self-regulated behaviors. Its genetic and environmental etiology, however, is not clearly understood during the important developmental period of adolescence. This study investigated the relative influence of genes and environment on self-reported impulsive traits in adolescent twins measured on two separate occasions (waves) between the ages of 11...

Niv, Sharon; Tuvblad, Catherine; Raine, Adrian; Wang, Pan; Baker, Laura A.

2011-01-01

321

Social influences of competition on impulsive choices in domestic chicks  

OpenAIRE

Social factors involved in the control of impulsiveness were examined in domestic chicks. In binary choices between a large/long-delay option (LL) and a small/short-delay alternative (SS), chicks that had been competitively trained in groups of three individuals showed fewer choices of LL than did those trained in isolation (experiment 1), suggesting that competition causes impulsive choice. In experiment 2, in order to identify the critical factor involved, we tested the effects of perceived...

Amita, Hidetoshi; Kawamori, Ai; Matsushima, Toshiya

2009-01-01

322

Switched impulsive control of the endocrine disruptor diethylstilbestrol singular model  

Science.gov (United States)

In this work, a switched and impulsive controller is designed to control the Endocrine Disruptor Diethylstilbestrol mechanism which is usually modeled as a singular system. Then the exponential stabilization property of the proposed switched and impulsive singular model is discussed under matrix inequalities. A design algorithm is given and applied for the physiological process of endocrine disruptor diethylstilbestrol model to illustrate the effectiveness of the results.

Zamani, Iman; Shafiee, Masoud; Ibeas, Asier; de la Sen, M.

2014-12-01

323

Prostaglandin E receptor EP1 controls impulsive behavior under stress  

OpenAIRE

Animals under stress take adaptive actions that may lead to various types of behavioral disinhibition. Such behavioral disinhibition, when expressed excessively and impulsively, can result in harm in individuals and cause a problem in our society. We now show that, under social or environmental stress, mice deficient in prostaglandin E receptor subtype EP1 (Ptger1-/-) manifest behavioral disinhibition, including impulsive aggression with defective social interaction, impaired cliff avoidance,...

Matsuoka, Yoko; Furuyashiki, Tomoyuki; Yamada, Kiyofumi; Nagai, Taku; Bito, Haruhiko; Tanaka, Yasuhiro; Kitaoka, Shiho; Ushikubi, Fumitaka; Nabeshima, Toshitaka; Narumiya, Shuh

2005-01-01

324

Removing Impulse Bursts from Images by Training-Based Filtering  

OpenAIRE

The characteristics of impulse bursts in remote sensing images are analyzed and a model for this noise is proposed. The model also takes into consideration other noise types, for example, 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 these techniques can provide an effective removal of impulse burs...

Pertti Koivisto; Jaakko Astola; Vladimir Lukin; Oleg Tsymbal; Vladimir Melnik

2003-01-01

325

Impulsive Noise Suppression from Images with the Noise Exclusive Filter  

OpenAIRE

A novel impulsive noise elimination filter, entitled noise exclusive filter (NEF), which shows a high performance at the restoration of images distorted by impulsive noise, is proposed in this paper. NEF uses chi-square goodness-of-fit test in order to detect the corrupted pixels more accurately. Simulation results show that the proposed filter achieves a superior performance compared with the other filters mentioned in this paper in terms of noise suppression and detail preservation, partic...

Alç? Mustafa; Be?dok Erkan; Nar, Ivicio Lu P.

2004-01-01

326

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

Science.gov (United States)

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. PMID:25615754

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

2015-02-01

327

Impulse pressuring diffusion bonding of titanium alloy to stainless steel  

International Nuclear Information System (INIS)

Impulse pressuring diffusion bonding between a titanium alloy TA17 and an austenitic stainless steel 0Cr18Ni9Ti has been carried out in vacuum. Relationships between the bonding parameters and the tensile strength of the joints were investigated, and the optimum bond parameters were obtained: bonding temperature T = 825 deg. C, maximum impulse pressure Pmax = 50 MPa, minimum impulse pressure Pmin = 8 MPa, number of impulses N = 30, impulse frequency f = 0.5 Hz. The maximum tensile strength of the joint was 321 MPa and the effective bonding time was only 180 s. The reaction products and the interface structure of the joints were investigated by optical microscopy, scanning electron microscopy (SEM), electron probe microanalysis (EPMA), and X-ray diffraction (XRD). The study revealed the existence of FeTi, Fe2Ti, ? phase and ?-Ti in the reaction zone. Brittle Fe-Ti intermetallic phases lower the strength and ductility of the impulse pressuring diffusion bonded couples significantly. This technique provides a reliable and efficient bonding method of titanium alloy and stainless steel

328

[Functional and dysfunctional impulsivity in young binge drinkers].  

Science.gov (United States)

The pattern of binge drinking (BD), found especially among young people, has become an important social and health problem. However, its prevalence has not been carefully studied until recently, together with its consequences in the mid and long run and the possible risk factors. The aim of this work is to study, for the first time, the possible differences in the dimensions of functional and dysfunctional impulsivity in Dickman's model among university students with BD and non-consumers of alcohol or control group. 80 subjects (40 men) with a pattern of BD and 80 controls (40 men) participated in the study, aged 18 to 25 (21,38 ± 1,91). They all completed Dickman's Impulsivity Inventory (DII, 1990). Several variables known to affect the results, such as circadian typology, were controlled for. The scores on dysfunctional impulsivity were higher in the BD group compared to the controls, while no differences were found according to functional impulsivity. Men showed a higher degree of impulsivity than women, both functional and dysfunctional, although in dysfunctional impulsivity this is significant only in the BD group. The DII has proven sensitive to detecting BD, and thus it could become an assessment tool to take into account in preventive or treatment approaches in the future. PMID:22508013

Adan, Ana

2012-01-01

329

Filament eruptions and the impulsive phase of solar flares  

International Nuclear Information System (INIS)

Filament motion during the onset of the solar flare impulsive phase is examined. The impulsive phase onset is established from profiles of about 30 keV X-ray fluxes and the rapid flare brightenings characteristic of the H-alpha flash phase. The filament motion begins several minutes before the impulsive or flash phase of the flare. No new accleration is observed in the motion of the filament during the onset of the impulsive phase for at least two of the four flares. The most common H-alpha brightenings associated with the impulsive phase lie near the magnetic inversion line roughly centered under the erupting filament. Filament speeds at the onset of the impulsive or flash phase lie in the range 30-180 km/s. These characteristics indicate that the filament eruption is not driven by the flare plasma pressure, but instead marks an eruption of magnetic field driven by a global MHD instability of the field configuration in the region of the flare. 36 references

330

Differences in self-reported and behavioral measures of impulsivity in recreational and dependent cocaine users  

OpenAIRE

BACKGROUND: Dependent cocaine users consistently display increased trait impulsivity on self-report questionnaires and less consistently exhibit elevated motor impulsivity in some behavioral tasks. However, trait and behavioral impulsivity measures have rarely been investigated in recreational users. Therefore, we examined self-reported trait and motor impulsivities in recreational and dependent cocaine users to clarify the role of impulse control in cocaine addiction and non-dependent cocain...

Vonmoos, Matthias; Hulka, Lea M.; Preller, Katrin H.; Jenni, Daniela; Schulz, Claudia; Baumgartner, Markus R.; Quednow, Boris B.

2013-01-01

331

On Impulsive Control for Synchronization and Its Application to Matsumoto-Chua-Kobayashi (MCK) Circuit  

International Nuclear Information System (INIS)

The issue of impulsive control theory for synchronization of the MCK circuit is developed. We propose an impulsive control scheme for the complete synchronization of the MCK circuit including chaotic systems. A sufficient condition for the impulsive control is derived, with an easily calculated maximum impulsive interval. The proposed impulsive control scheme is applied to the MCK circuit and the simulation result demonstrates the effectiveness of the method.

332

Impulsivity and Emotional Factors in Obesity: A Preliminary Study  

Directory of Open Access Journals (Sweden)

Full Text Available Objective: The aim of this study was to investigate the relationship of obesity with impulsivity and emotional factors. Met­hods: Forty-eight obese participants included in the study were compared with 48 normal-weight controls. The Structured Clinical Interview for DSM-IV Axis I Disorders (SCID-I, Eating Attitudes Test (EAT, Beck Depression Scale (BDS, and the Barrat Impulsiveness Scale-11 (BIS-11 were administered to all participants. Re­sults: Forty-eight obese participants were split into two groups: with regard to presence of binge eating disorder - binge eating group (22 subjects - 19 females and 3 males and non-binge eating group (26 subjects - 25 females and 1 males. No difference was detected between the groups in terms of impulsivity scores (p>0.05. Twenty-five of the 48 subjects with obesity were diagnosed with depressive disorder according to the DSM-IV criteria. Eight of the 48 control subjects had depressive disorder. Eating Attitudes Test and Beck Depression Scale scores were statistically significantly higher in the obese group than in the control group (p<0.05. We also compared the impulsivity scores between the depression and non-depression groups where impulsivity scores were found to be significantly higher in the depression group than in the non-depression group (p<0.05. Similarly, in the obese group, impulsivity scores of subjects with more elevated depression scores were significantly higher than those with lower depression scores (p<0.05. Conc­lu­si­on: The foremost finding of this study was determination of a stronger relationship between obesity and emotional traits than the relationship between obesity and impulsivity traits. In the current study, we also observed high impulsivity scores in the depression group. This result was associated more with the relationship between depression and impulsivity than with the relationship between obesity and impulsivity. Further studies with larger samples are required. (Arc­hi­ves of Neu­ropsy­chi­atry 2012; 49: 14-9

Fatma Özlem Orhan

2012-03-01

333

Acoustic radiation force impulse of the liver  

Directory of Open Access Journals (Sweden)

Full Text Available Acoustic radiation force impulse (ARFI imaging is a new and promising ultrasound-based diagnostic technique that, evaluating the wave propagation speed, allows the assessment of the tissue stiffness. ARFI is implemented in the ultrasound scanner. By short-duration acoustic radiation forces (less than 1 ms, localized displacements are generated in a selected region of interest not requiring any external compression so reducing the operator dependency. The generated wave scan provides qualitative or quantitative (wave velocity values responses. Several non-invasive methods for assessing the staging of fibrosis are used, in order to avoid liver biopsy. Liver function tests and transient elastography are non-invasive, sensitive and accurate tools for the assessment of liver fibrosis and for the discrimination between cirrhotic and non-cirrhotic liver. Many published studies analyse ARFI performance and feasibility in studying diffuse liver diseases and compare them to other diagnostic imaging modalities such as conventional ultrasonography and transient elastography. Solid focal liver lesions, both benign and malignant, are common findings during abdominal examinations. The accurate characterization and differential diagnosis are important aims of all the imaging modalities available today. Only few papers describe the application of ARFI technology in the study of solid focal liver lesions, with different results. In the present study, the existing literature, to the best of our knowledge, about ARFI application on diffuse and focal liver pathology has been evaluated and results and statistical analyses have been compared, bringing to the conclusion that ARFI can be used in the study of the liver with similar accuracy as transient elastography in diagnosing significant fibrosis or cirrhosis and has got some advantages in respect to transient elastography since it does not require separate equipment, better displays anatomical structures and measurements can be successfully carried out almost in every patient.

Mirko D’Onofrio

2013-01-01

334

Recreational use of "ecstasy" (MDMA) is associated with elevated impulsivity.  

Science.gov (United States)

Recent preclinical evidence suggests that repeated exposure to 3, 4-methylenedioxy-methamphetamine (MDMA; "ecstasy") produces long-term reductions in serotonin (5-HT) levels. 5-HT has been implicated in the regulation of mood, anxiety, aggression, impulsivity, and cognition. Accordingly, in the first of two separate studies, these variables were investigated in three groups: (1) MDMA group--recreational ecstasy users (who also used other illicit substances); (2) polydrug controls--who had never taken ecstasy, but otherwise had drug histories and personal characteristics similar to the ecstasy users; and (3) nondrug controls--who had never used illicit drugs, but had similar personal characteristics. All participants completed mood (Likert) scales, personality questionnaires (which included the impulsiveness, venturesomeness and empathy questionnaire-IVE), spatial span and "Tower of London" (TOL) tests, and a behavioural measure of impulsivity, the matching familiar figures test (MFF20). There were no group differences in mood, anxiety, anger/hostility, and cognitive performance, but the MDMA group committed significantly more errors in the MFF20. Subsequently, a larger sample of participants were administered mood (the General Health Questionnaire or GHQ) and personality (IVE) questionnaires before the administration of a TOL test, followed by the MFF20, and a second TOL test. Although there were no group differences in TOL performance, ecstasy users were again found to commit more errors in the MFF20 than polydrug users. Furthermore, the GHQ and IVE scores of the ecstasy users in the second study indicated, respectively, that they were more psychologically disturbed and impulsive than nondrug controls. The combined data from the two studies indicated that ecstasy users exhibited elevated impulsivity on both self-report and behavioral measures and that those who had taken the most ecstasy had the most elevated trait impulsiveness scores. These findings are consistent with previous evidence that elevated levels of impulsivity in humans are associated with reduced levels of serotonergic function. PMID:9718589

Morgan, M J

1998-10-01

335

The Impact of Visual Merchandising on Consumer Impulse Buying Behavior  

Directory of Open Access Journals (Sweden)

Full Text Available In present Post-Modern Era, the competitive situation in the business is characterized by a cut throat competition, which subsequently results in companies and retailers to pay almost anything for undifferentiated merchandising. This merchandising tool is being used by today’s retailer to distinguish him from other competitors, to be prominent in the market and become a source of attraction for the customers. A few researchers contribute in this field by exploring the reasons which causes the customers impulsive buying, but still there is more to be determined. Purpose of this study is to identify the relation between the consumer impulsive buying and visual merchandising on buying behavior of customers. This study was based on primary data in the form of a questioner. A total of 350 questioners were floated in different consumer outlets (super marts and self-service stores of Rawalpindi, Pakistan out of which 344 questioners were completed and received. Defined four hypotheses were window display, forum display, floor merchandising and shop brand name. These hypotheses were tested for regression analysis by using Statistical Packages for Social Sciences (SPSS software. It was found that window display, forum display, floor merchandising and shop brand name (independent variables are significantly associated to consumer impulse buying behavior (dependent variable. Hence, forum display is negatively related to consumer impulse buying and window display; however, floor merchandising and shop brand name are positively related to consumer impulse buying behavior.

Khurram L. Bhatti

2014-05-01

336

Modulating presence and impulsiveness by external stimulation of the brain  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background "The feeling of being there" is one possible way to describe the phenomenon of feeling present in a virtual environment and to act as if this environment is real. One brain area, which is hypothesized to be critically involved in modulating this feeling (also called presence is the dorso-lateral prefrontal cortex (dlPFC, an area also associated with the control of impulsive behavior. Methods In our experiment we applied transcranial direct current stimulation (tDCS to the right dlPFC in order to modulate the experience of presence while watching a virtual roller coaster ride. During the ride we also registered electro-dermal activity. Subjects also performed a test measuring impulsiveness and answered a questionnaire about their presence feeling while they were exposed to the virtual roller coaster scenario. Results Application of cathodal tDCS to the right dlPFC while subjects were exposed to a virtual roller coaster scenario modulates the electrodermal response to the virtual reality stimulus. In addition, measures reflecting impulsiveness were also modulated by application of cathodal tDCS to the right dlPFC. Conclusion Modulating the activation with the right dlPFC results in substantial changes in responses of the vegetative nervous system and changed impulsiveness. The effects can be explained by theories discussing the top-down influence of the right dlPFC on the "impulsive system".

Baumgartner Thomas

2008-08-01

337

Stochastic Particle Acceleration in Impulsive Solar Flares  

Science.gov (United States)

The acceleration of a huge number of electrons and ions to relativistic energies over timescales ranging from several seconds to several tens of seconds is the fundamental problem in high-energy solar physics. The cascading turbulence model we have developed has been shown previously (e.g., Miller 2000; Miller & Roberts 1995; Miner, LaRosa, & Moore 1996) to account for all the bulk features (such as acceleration timescales, fluxes, total number of energetic particles, and maximum energies) of electron and proton acceleration in impulsive solar flares. While the simulation of this acceleration process is involved, the essential idea of the model is quite simple, and consists of just a few parts: 1. During the primary flare energy release phase, we assume that low-amplitude MHD Alfven and fast mode waves are excited at long wavelengths, say comparable to the size of the event (although the results are actually insensitive to this initial wavelength). While an assumption, this appears reasonable in light of the likely highly turbulent nature of the flare. 2. These waves then cascade in a Kolmogorov-like fashion to smaller wavelengths (e.g., Verma et al. 1996), forming a power-law spectral density in wavenumber space through the inertial range. 3. When the mean wavenumber of the fast mode waves has increased sufficiently, the transit-time acceleration rate (Miller 1997) for superAlfvenic electrons can overcome Coulomb energy losses, and these electrons are accelerated out of the thermal distribution and to relativistic energies (Miller et al. 1996). As the Alfven waves cascade to higher wavenumbers, they can cyclotron resonate with progressively lower energy protons. Eventually, they will resonate with protons in the tail of the thermal distribution, which will then be accelerated to relativistic energies as well (Miller & Roberts 1995). Hence, both ions and electrons are stochastically accelerated, albeit by different mechanisms and different waves. 4. When the protons become superAlfvenic (above about 1 MeV/nucleon), they too can suffer transit-time acceleration by the fast mode waves and will receive an extra acceleration "kick." The basic overall objective of this 1 year effort was to construct a spatially-dependent version of this acceleration model and this has been realized.

Miller, James A.

2001-01-01

338

IMPULSES FOR THE POLICY OF EDUCATION TOWARDS THE KNOWLEDGE SOCIETY  

Directory of Open Access Journals (Sweden)

Full Text Available Shaping the knowledge society has become a priority for all the educational policies in member countries of the European Union. Within it, it is a specific quality of life based on people's ability to create value intangible nature, which may take the form of ideas, inventions or solutions of socio-economic character. A knowledge worker becomes the core workforce of the company. This worker works in a team, cooperates with individual members as well as with the group, develops ideas and actively shares knowledge. The way he works considerably varies as well as tools he uses at work. Our purpose is to identify the future competency model for new qualified workforce, which could be applicable for the educational policy, concretely for innovation of the educational and job standards In this paper we apply the theoretical analysis aimed at identifying the knowledge worker specifying the set of professional competencies in frame of 4 partial models, which are: personal competence, individual competence, social competence and societal competence. Through primary analysis we obtained information about preferences of his abilities, needed for changes in the educational system. The aim of this paper is to identify the basic characteristics of the knowledge worker and propose the competency model focusing on the personal, individual, social, and societal competence with its verification and proposal for improving the education standard. The result or our paper present suggest of the competency model of the knowledge worker, which would allow his definition on macro and micro level as well as identification new impulses for the educational policy. Fulfilment of the objective relates to the demanding requirements for qualified workforce in the knowledge society, from which is expected to more specialized knowledge, skills and work habits that would facilitate and promote mobility on the national and international level.

Antalová Mária

2014-12-01

339

Involvement of Serotonin Transporter Gene Polymorphisms (5-HTT) in Impulsive Behavior in the Japanese Population  

Science.gov (United States)

The serotonergic pathway has been implicated in the pathogenesis of impulsivity, and sensitivity to aversive outcomes may be linked to serotonin (5-HT) levels. Polymorphisms in the gene that encodes the serotonin transporter (5-HTT), which have differential effects on the level of serotonin transmission, display alternate responses to aversive stimuli. However, recent studies have shown that 5-HT does not affect motor function, which suggests that the functioning of the serotonin-transporter-linked polymorphic region (5-HTTLPR) does not directly affect the behavioral regulatory process itself, but instead exerts an effect via the evaluation of the potential risk associated with particular behavioral outputs. The aim of the present study was to examine the effect of specific 5-HTTLPR genotypes on the motor regulatory process, as observed during a Go/Nogo punishment feedback task. 5-HTT gene-linked promoter polymorphisms were analyzed by polymerase chain reaction, using lymphocytes from 61 healthy Japanese volunteers. Impulsivity was defined as the number of commission errors (responding when one should not) made during a Go/Nogo task. We found that the s/s genotype group made fewer impulsive responses, specifically under aversive conditions for committing such errors, compared to those in the s/l group, without affecting overall motor inhibition. These results suggest that 5-HTTLPRs do not directly affect the behavioral regulatory process itself, but may instead exert an effect on the evaluation of potential risk. The results also indicate that under such aversive conditions, decreased expression of 5-HTT may promote motor inhibitory control. PMID:25775400

Nomura, Michio; Kaneko, Masayuki; Okuma, Yasunobu; Nomura, Jun; Kusumi, Ichiro; Koyama, Tsukasa; Nomura, Yasuyuki

2015-01-01

340

A Methodology for Rapid Prototyping Peak-Constrained Least-Squares Bit-Serial Finite Impulse Response Filters in FPGAs  

OpenAIRE

Area-efficient peak-constrained least-squares (PCLS) bit-serial finite impulse response (FIR) filter implementations can be rapidly prototyped in field programmable gate arrays (FPGA) with the methodology presented in this paper. Faster generation of the FPGA configuration bitstream is possible with a new application-specific mapping and placement method that uses JBits to avoid conventional general-purpose mapping and placement tools. JBits is a set of Java classes that provide an interface...

Carreira Alex; Fox Trevor W; Turner Laurence E

2003-01-01

341

The Genesis of an Impulsive Coronal Mass Ejection observed at Ultra-High Cadence by AIA on SDO  

OpenAIRE

The study of fast, eruptive events in the low solar corona is one of the science objectives of the Atmospheric Imaging Assembly (AIA) imagers on the recently launched Solar Dynamics Observatory (SDO), which take full disk images in ten wavelengths with arcsecond resolution and 12 sec cadence. We study with AIA the formation of an impulsive coronal mass ejection (CME) which occurred on June 13, 2010 and was associated with an M1.0 class flare. Specifically, we analyze the for...

Patsourakos, S.; Vourlidas, A.; Stenborg, G.

2010-01-01

342

Nonlinear resonant interaction between acoustic impulse and electrons in superconductors  

International Nuclear Information System (INIS)

The problem of inelastic electron interaction in a perfectly pure superconductor with a longitudinal sound impulse is considered. It is shown that the problem reduces to the equivalent one of elastic scattering by the static potential, and the sound absorption is expressed in terms of the reflection coefficient of this scattering. The classical and quantum properties of the scattering are studied and the phase region in which new excitations are created is indicated. A formula is derived that expresses the density matrix of the excitations created in terms of the exact scattering matrix of an impulse. The quasiclassical creation of excitations by a smooth-shaped impulse is investigated with regard to both overbarrier and underbarrier processes

343

Behavior of viscoplastic circular plates under gaussian impulse  

International Nuclear Information System (INIS)

The dynamic plastic behavior of viscoplastic circular plates subjected to impulse loading is presented. The impulse is assumed to impart a transverse axisymmetric velocity with a spatial Gaussian distribution. The combined influence of membrane forces, bending moments and strain-rate sensitivity is considered in predicting the deformation. Numerical results are presented to show influence on the rate of growth of plastic regimes, the deflection configuration and the total time of response. It is concluded that the spatial distribution of impulse has a considerable effect on the deformation response of the plate, and relatively small effect on the total time of response; furthermore, the simple bending theory is inadequate to reliably predict the response. (orig.)

344

Research of Two Different Impulsive Faults of Rolling Element Bearing  

International Nuclear Information System (INIS)

Fans and pumps are key machines in process industries such as petrochemical and petroleum industries. Their faults can be catastrophic and result in costly downtime. Bearing fault is almost the most common fault of fans and pumps as rolling element bearings are widely used in these machines. Hence, condition monitoring and diagnosis of bearings are important. Two different impulsive faults of bearings have been observed and studied in previous research. The first fault presents very clear impulsive symptom in envelope spectrum, but the bearing can work for a long time. The other fault shows relatively indistinct symptom, but the bearing will break down in a short time. To overcome the problems of inaccurate diagnosis, a combinational approach based on an impulsive energy indicator and traditional enveloping analysis is proposed in this paper. This approach discriminate these two faults well and can support the maintenance decision for the machines with rolling element bearings.

345

Research of Two Different Impulsive Faults of Rolling Element Bearing  

Science.gov (United States)

Fans and pumps are key machines in process industries such as petrochemical and petroleum industries. Their faults can be catastrophic and result in costly downtime. Bearing fault is almost the most common fault of fans and pumps as rolling element bearings are widely used in these machines. Hence, condition monitoring and diagnosis of bearings are important. Two different impulsive faults of bearings have been observed and studied in previous research. The first fault presents very clear impulsive symptom in envelope spectrum, but the bearing can work for a long time. The other fault shows relatively indistinct symptom, but the bearing will break down in a short time. To overcome the problems of inaccurate diagnosis, a combinational approach based on an impulsive energy indicator and traditional enveloping analysis is proposed in this paper. This approach discriminate these two faults well and can support the maintenance decision for the machines with rolling element bearings.

Jiang, Zhinong; Xing, Chenghong; Feng, Kun; Gao, Jinji

2012-05-01

346

Fuzzy modelling and impulsive control of the hyperchaotic Lü system  

International Nuclear Information System (INIS)

This paper presents a novel approach to hyperchaos control of hyperchaotic systems based on impulsive control and the Takagi–Sugeno (T–S) fuzzy model. In this study, the hyperchaotic Lü system is exactly represented by the T–S fuzzy model and an impulsive control framework is proposed for stabilizing the hyperchaotic Lü system, which is also suitable for classes of T–S fuzzy hyperchaotic systems, such as the hyperchaotic Rössler, Chen, Chua systems and so on. Sufficient conditions for achieving stability in impulsive T–S fuzzy hyperchaotic systems are derived by using Lyapunov stability theory in the form of the linear matrix inequality, and are less conservative in comparison with existing results. Numerical simulations are given to demonstrate the effectiveness of the proposed method

347

Measuring long impulse responses with pseudorandom sequences and sweep signals  

DEFF Research Database (Denmark)

In architectural acoustics, background noise, loudspeaker nonlinearities, and time variances are the most common disturbances that can compromise a measurement. The effects of such disturbances on measurement of long impulse responses with pseudorandom sequences (maximum-length sequences (MLS) and inverse repeated sequences (IRS)) and with linear and logarithmic sweep signals have been examined. The results reveal that the sweep method can provide a significant reduction of the effect of distortion compared with MLS/IRS techniques but, unlike what is claimed in the literature, sweep signals cannot reject all distortion artifacts from the causal part of the estimated impulse response. In all cases, an improvement of 3 dB in signal-to-noise ratio can be achieved if the measurement time is doubled either by averaging over two excitations or by doubling the length of the excitation signal. The time-frequency selectivity performed by the sweep technique is found to yield higher immunity to impulsive noise and timevariances.

Torras Rosell, Antoni Technical University of Denmark,

2010-01-01

348

Fuzzy modelling and impulsive control of the hyperchaotic Lü system  

Science.gov (United States)

This paper presents a novel approach to hyperchaos control of hyperchaotic systems based on impulsive control and the Takagi-Sugeno (T-S) fuzzy model. In this study, the hyperchaotic Lü system is exactly represented by the T-S fuzzy model and an impulsive control framework is proposed for stabilizing the hyperchaotic Lü system, which is also suitable for classes of T-S fuzzy hyperchaotic systems, such as the hyperchaotic Rössler, Chen, Chua systems and so on. Sufficient conditions for achieving stability in impulsive T-S fuzzy hyperchaotic systems are derived by using Lyapunov stability theory in the form of the linear matrix inequality, and are less conservative in comparison with existing results. Numerical simulations are given to demonstrate the effectiveness of the proposed method.

Zhang, Xiao-Hong; Li, Dong

2009-05-01

349

Experimental study on impulsive liquid pressure by sloshing  

International Nuclear Information System (INIS)

Pool type FBR (Fast Breeder Reactor) vessel contains large quantity (about 3,000 ? 4,000 tons) of high temperature (about 400 ? 500degC) liquid sodium with free surface. Sloshing wave gradually grow during earthquake and this liquid surface may collide with under roof of reactor vessel, cousing large impulsive pressure on heat insulator assembly under the roof. In this paper, we describe an experimental study of impulsive pressure by sloshing. Model used in this experiments are cylindrical (2.2 m Diameter; 1 m Depth), and two rectangular (6.7 m Length, 2 m Width; 2.5 m Depth, and 0.55 m Length; 0.2 m Width; 0.2 m Depth) models. In this experiment, we use water instead of liquid sodium, because water can be handled more easily than liquid sodium. From the experimental results, we derived a formula to obtain impulsive pressure value. (author)

350

FPGA IMPLEMENTATION OF RSEPD TECHNIQUE BASED IMPULSE NOISE REMOVAL  

Directory of Open Access Journals (Sweden)

Full Text Available In the process of signals transmission and acquisition, image signals might be corrupted by impulse noise. Generally, digital images are corrupted by impulse noises. These are short duration noises, which degrade an image and are randomly distributed over the image. An efficient FPGA implementation for removing impulse noise in an image is presented in this paper. Existing techniques use standard median filter. These existing approaches changes the pixel values of both noise less and noisy pixels, so image might be blurred in nature. To avoid the changes on noise less pixels, an efficient FPGA implementation of Simple Edge Preserved De-noising technique (SEPD and Reduced Simple Edge Preserved De-noising technique (RSEPD are presented in this paper. In this technique, noise detection and noise removal operations are performed. This VLSI design gives better image quality. For 10 percentage noise added image, the obtained PSNR value of the image is 31.68 while de-noising it.

M. Rajadurai

2013-05-01

351

An approach to remove impulse noise from a corrupted image  

International Nuclear Information System (INIS)

In this paper, we propose an efficient approach for detecting the impulse noise from corrupted images. This method is based on the principle that the feature of the digital image is usually local correlation and the feature of the impulse noise is usually located near one of the two ends of the image’s maximum and minimum gray values. After the noisy pixel has been detected by the proposed detector, a modified version of the mean filter is proposed to remove the detected impulse noise. Experimental results show that the implementation of the proposed method is simple, and it has better performance than comparison filters with regard to effective noise suppression and preservation of detail, especially when the noise ratio is very high. (paper)

352

Impulse Electrotherapy in Reduction Treatment of the Tuboperitoneal Steri  

Directory of Open Access Journals (Sweden)

Full Text Available Aim of investigation is assessment of the impulse electrotherapy clinical effectiveness in a complex treatment of patients with the tuboperitoneal sterility.Materials and methods. A complex clinicolaboratory examination of 114 patients with the tuboperitoneal sterility (TPS is made. All the females were divided into 3 groups. The females underwent a laparoscopic operation and ultrasonic therapy in the impulse mode to a suprapubic zone in the early postoperative period (10—15 procedures in the 1st control group (n=30. The females underwent a laparoscopic operation and a course of impulse electrotherapy with the «SCANAR-1-HT» apparatus with a use of vaginal electrode (10—15 procedures in the 2nd group (n=42. A course of impulse electrotherapy was conducted without a vaginal electrode use (10—15 procedures in the 3d group (n=42. Two parameters were considered at assessment of the female reproductive function reduction: a conservation of the uterine tube permeability after laparoscopy and a spontaneous pregnancy beginning. A hysterosalpingography was made in all the patients in 2—3 months after a reduction treatment.Results. An impulse electrotherapy used in the early reduction period after a laparoscopic operation in patients with the tuboperitoneal sterility improves the uterine tube permeability conservation values by 28%, the fertility values — by 20% compared to a group, where an ultrasonic therapy in the impulse mode was used in the early reduction period.The proposed method normally effects the lipid peroxidation and antioxidant system state, a homeostasis, leads to a hemodynamics normalization in the small pelvis organs, a decrease of the organism regulatory mechanism tension degree, a decrease of a sympathetic nervous system influence and increase of a parasympathetic nervous system tonus, has an expressed psychocorrugating effect.

T.E. Belousova

2010-03-01

353

Impulsive-reflective cognitive style, metacognition, and emotion in adolescence.  

Science.gov (United States)

The study investigated the relationship between reflective or impulsive cognitive style, metacognitive functioning, and depression in young adolescents. Metacognitive functioning (metacognitive knowledge about reading and memory, monitoring of text comprehension) and self-reported depressive feelings were analyzed in a group of subjects who showed a Reflective or Impulsive cognitive style. The sample consisted of 56 junior high-school students (Grades 6, 7, and 8) selected from a larger original group of 61 subjects. We excluded from the original group those with an IQ below 75 on both the Verbal and Performance subscales on the short form of the WISC-R, those reported by teachers to have a severe learning disability, and those that did not complete the test battery due to long absences from school. The reflective-impulsive cognitive style was identified with the Matching Familiar Figures Test-20. Using the median of the distribution for both Latency (17 sec. per item) and Errors (9 errors) on this task, the sample was divided in four partially overlapping subgroups: 16 with Impulsive cognitive style (Latency below the median, Errors above the median), 13 with Reflective cognitive style (Latency above the median, Error below the median), 4 fast and accurate (both scores below the median), and 11 slow and inaccurate (both scores above the median). Twelve subjects with one or both scores coinciding with the critical value (median) were excluded. Analysis showed that subjects with Impulsive cognitive style had significantly lower scores than those with Reflective cognitive style in monitoring of comprehension of text. No differences were found on monitoring by eighth graders, irrespective of cognitive style. No differences between the two groups were found in metacognitive knowledge. Subjects with Impulsive cognitive style had significantly higher scores than subjects with Reflective cognitive style on a self-rating scale for childhood depression, the Children's Depression Inventory. The implications of these data are discussed. PMID:9132733

Palladino, P; Poli, P; Masi, G; Marcheschi, M

1997-02-01

354

Model Predictive Control based on Finite Impulse Response Models  

DEFF Research Database (Denmark)

We develop a regularized l2 finite impulse response (FIR) predictive controller with input and input-rate constraints. Feedback is based on a simple constant output disturbance filter. The performance of the predictive controller in the face of plant-model mismatch is investigated by simulations and related to the uncertainty of the impulse response coefficients. The simulations can be used to benchmark l2 MPC against FIR based robust MPC as well as to estimate the maximum performance improvements by robust MPC.

Prasath, Guru; JØrgensen, John Bagterp

2008-01-01

355

Impulsive electromagnetic response of thin plasmonic metal sheets  

Science.gov (United States)

The impulsive electromagnetic response of a thin metallic coating on a dielectric half-space is analytically investigated. Both TM- and TE-polarized electromagnetic fields in the configuration are excited by an impulsive line source. The problem is analytically solved with the help of the high-contrast thin-sheet boundary conditions and the extended Cagniard-DeHoop technique. Closed-form space-time expressions for electromagnetic fields are found, numerically evaluated, and discussed with regard to the pulsed excitation of surface plasmon phenomena.

Å tumpf, M.; Vandenbosch, Guy A. E.

2014-08-01

356

Impulsive and hybrid dynamical systems stability, dissipativity, and control  

CERN Document Server

This book develops a general analysis and synthesis framework for impulsive and hybrid dynamical systems. Such a framework is imperative for modern complex engineering systems that involve interacting continuous-time and discrete-time dynamics with multiple modes of operation that place stringent demands on controller design and require implementation of increasing complexity--whether advanced high-performance tactical fighter aircraft and space vehicles, variable-cycle gas turbine engines, or air and ground transportation systems. Impulsive and Hybrid Dynamical Systems goes beyond similar

Haddad, Wassim M; Nersesov, Sergey G

2014-01-01

357

Solar Flare Impulsive Phase Emission Observed with SDO/EVE  

OpenAIRE

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 = 5.8 - 7.2 allow the evolution of the DEM to be studied over a wide temperature range at 10s cadence. The technique was applied to several M- and X-class flares, where impulsive phase EUV emission is observable in...

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

2013-01-01

358

DDCS interface system for safety logic with Fine Impulse Test  

International Nuclear Information System (INIS)

DDCS interface system for Safety Logic with Fine Impulse Test (SLFIT) is developed for communicating reactor trip annunciations and logic fault annunciations to Distributed Digital Control System (DDCS). DDCS Interface system acquires Reactor trip annunciations at various stages of Safety Logic. It acquires various faults of Safety Logic and FIT logic. Trip annunciations, Logic faults and health status are scanned periodically and sent to Distributed Digital Control System. This paper describes the input signals, output packets, processing logic, architecture and software design of DDCS interface system for Safety Logic with Fine Impulse Test. (author)

359

Filtered backprojection for modifying the impulse response of circular tomosynthesis  

International Nuclear Information System (INIS)

A filtering technique has been developed to modify the three-dimensional impulse response of circular motion tomosynthesis to allow the generation of images whose appearance is like those of some other imaging geometries. In particular, this technique can reconstruct images with a blurring function which is more homogeneous for off-focal plane objects than that from circular tomosynthesis. In this paper, we describe the filtering process, and demonstrate the ability to alter the impulse response in circular motion tomosynthesis from a ring to a disk. This filtering may be desirable because the blurred out-of-plane objects appear less structured

360

Impulsive differential equations asymptotic properties of the solutions  

CERN Document Server

The question of the presence of various asymptotic properties of the solutions of ordinary differential equations arises when solving various practical problems. The investigation of these questions is still more important for impulsive differential equations which have a wider field of application than the ordinary ones.The results obtained by treating the asymptotic properties of the solutions of impulsive differential equations can be found in numerous separate articles. The systematized exposition of these results in a separate book will satisfy the growing interest in the problems related

Bainov, DD

1995-01-01

361

The Impulse Response of an Exponential Assembly  

International Nuclear Information System (INIS)

A spatial-dependent transfer function of an exponential assembly with rectangular geometry and the neutron source located at the origin in the middle of one side has been derived using diffusion theory and the usual approximations. If the end correction factor is neglected, the result G (x, y, z, s) = (??(x, y, z, s))/?S (o, o, o, o, s) = 2/abD ??m = 1 ??n = 1 1/(?mn(s) cos (m?x)/a cos (n?y)/b e-?mn(s)Z (1) where ?mn(s) = [s/(VD) + B2?mn - B2m]1/2 = [s/VD - ?2mn]1/2 (2) The inverse Laplace transform of Eq. (1) gives the spatial dependent impulse response function (Green's function) to be g (x, y, z, t) = 2/ab ?v/?D 1/?t e-z2/4 VDt ??m = 1 ??n = 1 cos m?x/a cos n?y/b e-VD?2mnt (3) If only the terms of Eq. (3) outside the double summation are considered (i.e. multiplicative and leakage effects are neglected) the result is 2/ab ?V/?D 1/?t e-z2/4 VDt = 4V/ab P(z), (4) where P(z) is a Gaussian distribution term of the form P(z) = 1/o?2? e-z2/2?2 (5) with a time dependent standard deviation o o = ?2 VDt. (6) Hence, a pulse of thermal neutrons introduced at the origin spreads Out with time in a symmetrical manner about the z = 0 plane. However, the variation of amplitude with time at any position along the z axis shows that a peak value of neutron density does move out from the origin with a decreasing amplitude. Although the multiplication and transverse leakage influence the characteristics of the disturbance, it does propagate away from the source in a manner similar to the propagation of neutron waves. The propagation of a thermal-neutron pulse has been demonstrated experimentally in 1962 at the University of Florida using a pulsed-neutron source and a ''Thermalizer box''. However, the method used for the experiments reported here was the cross correlation between the pseudo-random binary (off-on) variation of source strength and the resulting variation of neutron density in the exponential assembly. Data are given for experiments carried out on both light- and heavy-water moderated assemblies using natural uranium. The results are discussed in terms of the theoretical relations derived and the physical phenomena taking place. The validity of the derived relationships and the need for considering higher harmonics for various arrangements of fuel and moderator are discussed briefly. (author)

362

Excessive Eating and Compulsive Buying Behaviours in Women: An Empirical Pilot Study Examining Reward Sensitivity, Anxiety, Impulsivity, Self-Esteem and Social Desirability  

Science.gov (United States)

"Mall disorders" such as excessive eating and compulsive buying appear to be increasing, particularly among women. A battery of questionnaires was used in an attempt to determine this association between specific personality traits (i.e., reward sensitivity, impulsivity, cognitive and somatic anxiety, self-esteem, and social desirability) and…

Davenport, Kate; Houston, James E.; Griffiths, Mark D.

2012-01-01

363

IMPULSE RESPONSE OF THE ACOUSTIC DIFFRACTION : A THEORETICAL ESTIMATION AND ITS EXPERIMENTAL VERIFICATION  

OpenAIRE

Theoretical formulation of the diffraction is presented to obtain the impulse response of the diffraction at a straight edge. Theoretical calculations are experimentally verified by direct observation of the impulse response using a micro spark.

Otani, T; Kubota, S.

1990-01-01

364

Energy spectrum of corona impulses generated from insulated wires under high a.c. voltages  

Science.gov (United States)

This paper suggests methods for calculating spectral energy densities of corona impulses generated from insulated conductors. The calculation is based on the data obtained from the measurement of corona pulse waveforms, repetition rates and relevant statistical properties of corona impulses.

Doreswamy, C. V.; Padiyar, K. R.; Crowell, C. S.

1978-01-01

365

Time-fixed rendezvous by impulse factoring with an intermediate timing constraint. [for transfer orbits  

Science.gov (United States)

A method is presented for factoring a two-impulse orbital transfer into a three- or four-impulse transfer which solves the rendezvous problem and satisfies an intermediate timing constraint. Both the time of rendezvous and the intermediate time of a alinement are formulated as any element of a finite sequence of times. These times are integer multiples of a constant plus an additive constant. The rendezvous condition is an equality constraint, whereas the intermediate alinement is an inequality constraint. The two timing constraints are satisfied by factoring the impulses into collinear parts that vectorially sum to the original impulse and by varying the resultant period differences and the number of revolutions in each orbit. Five different types of solutions arise by considering factoring either or both of the two impulses into two or three parts with a limit for four total impulses. The impulse-factoring technique may be applied to any two-impulse transfer which has distinct orbital periods.

Green, R. N.; Kibler, J. F.; Young, G. R.

1974-01-01

366

On periodic boundary value problems of first-order perturbed impulsive differential inclusions  

Directory of Open Access Journals (Sweden)

Full Text Available In this paper we present an existence result for a first order impulsive differential inclusion with periodic boundary conditions and impulses at the fixed times under the convex condition of multi-functions.

Bapurao C. Dhage

2004-06-01

367

Quasilinearization for the periodic boundary value problem for systems of impulsive differential equations  

OpenAIRE

The method of generalized quasilinearization for the system of nonlinear impulsive differential equations with periodic boundary conditions is studied. As a byproduct, the result for the system without impulses can be obtained, which is a new result as well.

Hristova, S. G.; Vatsala, A. S.

2006-01-01

368

Use Impulse Response Sequences in the Construction of Number Sequence Identities  

OpenAIRE

We define impulse response sequence in the set of all linear recurring sequences satisfying a linear recurrence relation of order $r$. The generating function and expression of the impulse response sequence are presented. Some identities of impulse response sequences including a type of nonlinear expressions are established. The interrelationship between the impulse response sequence and other linear recurring sequences in the same set is given, which is used to transfer the...

He, Tian-xiao

2013-01-01

369

Information criteria for impulse response function matching estimation of DSGE models  

OpenAIRE

We propose a new information criterion for impulse response function matching estimators (IRFMEs) of the structural parameters of dynamic stochastic general equilibrium (DSGE) macroeconomic models. An advantage of our procedure is that it allows researchers to select the impulse responses that are most informative about DSGE model parameters and ignore the rest. The idea of tossing out superfluous impulse responses motivates our Redundant Impulse Response Selection Criterion (RIRSC). The RIRS...

Hall, Alastair; Inoue, Atsushi; Nason, James M.; Rossi, Barbara

2008-01-01

370

Understanding the construct of impulsivity and its relationship to alcohol use disorders  

OpenAIRE

There are well-established links between impulsivity and alcohol use in humans and other model organisms; however, the etiological nature of these associations remains unclear. This is likely due, in part, to the heterogeneous nature of the construct of impulsivity. Many different measures of impulsivity have been employed in human studies, using both questionnaire and laboratory-based tasks. Animal studies also use multiple tasks to assess the construct of impulsivity. In both human and anim...

Dick, Danielle M.; Smith, Gregory; Olausson, Peter; Mitchell, Suzanne H.; Leeman, Robert F.; O Malley, Stephanie S.; Sher, Kenneth

2010-01-01

371

Impulsive synchronisation of a class of fractional-order hyperchaotic systems  

International Nuclear Information System (INIS)

In this paper, an impulsive synchronisation scheme for a class of fractional-order hyperchaotic systems is proposed. The sufficient conditions of a class of integral-order hyperchaotic systems' impulsive synchronisation are illustrated. Furthermore, we apply the sufficient conditions to a class of fractional-order hyperchaotic systems and well achieve impulsive synchronisation of these fractional-order hyperchaotic systems, thereby extending the applicable scope of impulsive synchronisation. Numerical simulations further demonstrate the feasibility and effectiveness of the proposed scheme. (general)

372

Rated and measured impulsivity in children is associated with diminished cardiac reactions to acute psychological stress.  

Science.gov (United States)

This study examined the association between impulsivity and heart rate reactions to a brief psychological stress in pre-adolescent children. Impulsivity was assessed by two response inhibition tasks and maternal self-report. Heart rate was measured at rest and in response to a mental arithmetic challenge. Children high in impulsivity showed blunted cardiac stress reactions. This result resonates with previous findings that blunted stress reactivity is characteristic of a range of problematic behaviours often associated with impulsivity. PMID:25038303

Bennett, Carmel; Blissett, Jackie; Carroll, Douglas; Ginty, Annie T

2014-10-01

373

Recreational Drug Use and Impulsivity in a Population of Canadian Undergraduate Drinkers  

OpenAIRE

The consumption of drugs during young adulthood may be particularly detrimental given important neurodevelopmental changes occurring during this period. As impulsivity may lead to substance use and substance use to the commission of seemingly impulsive acts, an improved understanding of the relationship between alcohol use, other substance use and impulsivity in young adults is important. We gathered information on self-reported impulsivity, recreational drug use, and drinking habits of 205 (...

IrisMBalodis; MarcNPotenza

2010-01-01

374

A Decision tree and Conditional Median Filter Based Denoising for impulse noise in images  

OpenAIRE

Impulse noise is often introduced into images during acquisition and transmission. Even though so many denoising techniques are existing for the removal of impulse noise in images, most of them are high complexity methods and have only low image quality. Here a low cost, low complexity VLSI architecture for the removal of random valued impulse noise in highly corrupted images is introduced. In this technique a decision- tree- based impulse noise detector is used to detect the noisy pixels and...

Shiby. S,; Asha Sunil

2014-01-01

375

Understanding Computation of Impulse Response in Microwave Software Tools  

Science.gov (United States)

In modern microwave engineering curricula, the introduction of the many new topics in microwave industrial development, or of software tools for design and simulation, sometimes results in students having an inadequate understanding of the fundamental theory. The terminology for and the explanation of algorithms for calculating impulse response in…

Potrebic, Milka M.; Tosic, Dejan V.; Pejovic, Predrag V.

2010-01-01

376

Impulse and Frequency Response of a Moving Coil Galvanometer.  

Science.gov (United States)

Describes an undergraduate laboratory experiment in which a moving coil galvanometer is studied and the electromotive force generated by the swinging coil provides the impulse response information in a form suitable for digitizing and inputing to a microcomputer. Background information and analysis of typical data are included. (JN)

McNeill, D. J.

1985-01-01

377

Response of calandria vessel to impulse pressure loading  

International Nuclear Information System (INIS)

Th response of a typical calandria vessel in a CANDU (Canada deuterium uranium) reactor to an extreme pressure loading due to a fuel channel failure is presented. The calandria vessel, which is a stepped cylinder, is treated as a thin elastic shell for analysis purposes. Depending on the time duration of the applied pressure loading relative to the periods of natural vibration, the loading can be treated as either static, dynamic or impulse loading. The static analysis is used to identify the highly stressed regions of the shell and to estimate the collapse pressure based on ASME code. In the dynamic analysis the pressure loading on the shell is assumed to consists of either a series of impulse loads or a large dynamic load. The effect of impulse loading is assessed in terms of the plastic strain accumulated at the critical locations. The main stress state in the calandria vessel under the extreme loading and an estimate of the impulse required for failure of the vessel are presented. The effect of any surrounding shielding water on the results and the likely failure modes are briefly discussed. (orig.)

378

Response of ion acoustic waves to an impulse  

International Nuclear Information System (INIS)

Linear response of ion acoustic waves to an impulse has been numerically calculated using an exact dispersion relation. Two experiments have been simulated. Excellent agreement has been seen for a stable plasma, while for an unstable plasma, a positive frequency shift is observed. (author)

379

Electroweak nuclear response in the impulse approximation regime  

International Nuclear Information System (INIS)

I outline a formalism, based on nonrelativistic many-body theory, suitable to describe the electroweak nuclear response in the impulse approximation regime. This approach allows for a unified treatment of a variety of processes, including quasi elastic scattering, coherent and incoherent pion production and deep inelastic scattering. The results of selected calculations of electron- and neutrino-nucleus scattering observables are analyzed

380

Impulse response measurements with an off-line cross correlator  

International Nuclear Information System (INIS)

The impulse responses of simulated systems have been computed by off-line cross-correlation of the system input and output signals. The input test signal consisted of a discrete interval binary code whose autocorrelation was a triangular pulse at zero lag. The main object of the experiments was to study the inaccuracies introduced in ideal, noise free systems by determining the impulse response digitally from sampled versions of the system input and output signals. A second object was to determine the error introduced by adding controlled amounts of uncorrelated noise at the system outputs. The experimental results showed that for signal to noise ratios greater than 10:1 in the mean square sense, the impulse responses may be determined with reasonable accuracy using only one cycle of the binary code. The method lends itself to on-line computation of system impulse responses. The latter could be used to monitor the stability of the system or to determine control parameters in an adaptive control system. (author)

381

Some Applications of Impulse Control in Mathematical Finance  

OpenAIRE

We consider three applications of impulse control in financial mathematics, a cash management problem, optimal control of an exchange rate, and portfolio optimisation under transaction costs. We sketch the different ways of solving these problems with the help of quasi-variational inequalities. Further, some viscosity solution results are presented.

Korn, Ralf

1999-01-01

382

Impulsivity, gender, and the platelet serotonin transporter in healthy subjects  

OpenAIRE

Donatella Marazziti, Stefano Baroni, Irene Masala, Francesca Golia, Giorgio Consoli, Gabriele Massimetti, Michela Picchetti, Mario Catena Dell’Osso, Gino Giannaccini, Laura Betti, Antonio Lucacchini, Antonio CiapparelliDipartimento di Psichiatria, Neurobiologia, Farmacologia e Biotecnologie, University of Pisa, Pisa, ItalyAbstract: The present study explored the possible relationships between impulsivity, gender, and a peripheral serotonergic marker, the platelet serotonin (5-HT) tr...

Donatella Marazziti; Stefano Baroni; Irene Masala; et al.

2009-01-01

383

Almost Periodic Solutions for Impulsive Fractional Stochastic Evolution Equations  

OpenAIRE

In this paper, we consider the existence of square-mean piecewise almost periodic solutions for impulsive fractional stochastic evolution equations involving Caputo fractional derivative. The main results are obtained by means of the theory of operators semi-group, fractional calculus, fixed point technique and stochastic analysis theory and methods adopted directly from deterministic fractional equations. Some known results are improved and generalized.

Toufik Guendouzi; Lamia Bousmaha

2014-01-01

384

Parents' Reactions to Youths' Hyperactivity, Impulsivity, and Attention Problems  

Science.gov (United States)

Hyperactivity, impulsivity, and attention problems (HIA) in children and adolescents are stressful for parents. In this study, we used theories of parents' perceived power and attributions for youths' behaviors to develop a model to understand parents' reactions to their youths' HIA. We followed 706 youths (376 boys and 330 girls, aged 10-12 years…

Glatz, Terese; Stattin, Hakan; Kerr, Margaret

2011-01-01

385

Analysis of a developed analog trilateration system of impulsive sounds  

Science.gov (United States)

A characterization study is made from a trilateration system for impulsive sounds, in which theoretical analysis and experimental results are presented. This system uses an analog trilateration method, avoiding to implement high frequency ADC conversion elements. It also presents the optimization of the chosen array of microphones, thus allowing for a better trilateration algorithm behavior.

López R., Juan Manuel; Marulanda B., Jose Ignacio

2014-05-01

386

Treating Cognitively Impulsive Children Using Academic Materials and Peer Models.  

Science.gov (United States)

The effectiveness of a peer-modeling treatment in the modification of impulsive cognitive style and in the improvement of academic performance in the areas of reading, spelling and arithmetic is investigated in this study. In four single case experiments, eight fifth grade children identified by the Matching Families Figures Test Form 20 (MFF20)…

Herman, Barbara; And Others

387

Solar Flare Impulsive Phase Emission Observed with SDO/EVE  

CERN Document Server

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 = 5.8 - 7.2 allow the evolution of the DEM to be studied over a wide temperature range at 10s 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 one from 7 - 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 emissi...

Kennedy, Michael B; Mathioudakis, Mihalis; Keenan, Francis P

2013-01-01

388

Impulsive behavior in solar soft X-radiation  

Science.gov (United States)

The Yohkoh soft X-ray telescope has observed impulsive, thermal, soft X-ray emission at the footpoints of magnetic loops during solar flares. The soft X-ray (thermal) time profiles at the footpoints closely match the hard X-ray (nonthermal) time profiles, directly demonstrating the heating of the lower solar atmosphere on short timescales during the interval of nonthermal energy release. This phenomenon is the rule, rather than the exception, occurring in the majority of flares that we have examined with the Yohkoh data. We illustrate the impulsive behavior with data from the major flare of 1992 January 26. For this flare, the soft X-ray peak times matched the hard X-ray peak times within the time resolution of the soft X-ray measurements (about 10 s), and the soft and hard X-ray locations match within the resolution of the hard X-ray imager. The impulsive soft X-ray emission clearly has a thermal spectral signature, but not at the high temperature of a 'superhot' source. We conclude that the impulsive soft X-ray emission comes from material heated by precipitating electrons at loop footpoints and evaporating from the deeper atmosphere into the flaring flux tube.

Hudson, H. S.; Strong, K. T.; Dennis, B. R.; Zarro, D.; Inda, M.; Kosugi, T.; Sakao, T.

1994-01-01

389

Chaotification of discrete dynamical systems via impulsive control  

International Nuclear Information System (INIS)

This Letter is concerned with chaotification of discrete dynamical systems in finite-dimensional real spaces, via impulsive control techniques. Chaotification theorems for one-dimensional discrete dynamical systems and general higher-dimensional discrete dynamical systems are derived, respectively, whether the original systems are stable or not. Finally, the effectiveness of the theoretical results is illustrated by some numerical examples.

390

Cone-valued impulsive differential and integrodifferential inequalities  

OpenAIRE

In this paper, we present impulsive analogues of the Gronwall-Bellman inequalities. Conditions for the existence of maximal solutions of some integrodifferential equations are obtained by finding upper bounds for these inequalities. Using monotone iterative techniques and a fixed point theorem, we obtained a priori estimates for the inequalities.

Sam Olatunji Ale; Benjamin Oyediran Oyelami; Sesay, Maligie S.

2005-01-01

391

Positive solutions of some nonlocal impulsive boundary value problem  

OpenAIRE

We prove new results on the existence of positive solutions for some impulsive differential equation subject to nonlocal boundary conditions. Our boundary conditions involve an affine functional given by a Stieltjes integral. These cover the well known multi-point boundary conditions that are studied by various authors.

Infante, Gennaro; Pietramala, Paolamaria

2013-01-01

392

Cognitive Processes in the Reflective-Impulsive Cognitive Style  

Science.gov (United States)

In this study, the authors improved the understanding of the cognitive processes underlying the reflective-impulsive cognitive style (RI), which was initially measured by J. Kagan, B. L. Rosman, D. Day, J. Albert, and W. Phillips (1964) on the Matching Familiar Figures Test (MFFT). The authors determined the relationships between the RI style and…

Rozencwajg, Paulette; Corroyer, Denis

2005-01-01

393

Filtering of the Color Images Distorted by Impulse Noise  

Directory of Open Access Journals (Sweden)

Full Text Available The paper deals with color image filtering distorted by impulsenoise. The component, transformation, and vector filtering areanalyzed. The filters are evaluated besides the classical criteria(mean absolute error and mean square error, and by the colordifference criterion. Moreover, use of the impulse detectors in thecolor image filtration is analyzed.

C. Stupak

2001-09-01

394

Periodic components of hand acceleration/deceleration impulses during telemanipulation  

Energy Technology Data Exchange (ETDEWEB)

Responsiveness is the ability of a telemanipulator to recreate user trajectories and impedance in time and space. For trajectory production, a key determinant of responsiveness is the ability of the system to accept user inputs, which are forces on the master handle generated by user hand acceleration/deceleration (a/d) impulses, and translate them into slave arm acceleration/deceleration. This paper presents observations of master controller a/d impulses during completion of a simple target acquisition task. Power spectral density functions (PSDF`s) calculated from hand controller a/d impulses were used to assess impulse waveform. The relative contributions of frequency intervals ranging up to 25 Hz for three spatially different versions of the task were used to determine which frequencies were most important. The highest relative power was observed in frequencies between 1 Hz and 6 Hz. The key frequencies related to task difficulty were in the range from 2 Hz to 8 Hz. the results provide clues to the source of the performance inhibition.

Draper, J.V. [Oak Ridge National Lab., TN (United States); Handel, S. [Tennessee Univ., Knoxville, TN (United States). Dept. of Psychology

1994-01-01

395

An update on impulse control disorders in Parkinson's disease  

OpenAIRE

The impulse control disorders associated with dopaminergic medication in Parkinson's disease provide a clear and unequivocal demonstration of the biological basis of behavioural addiction. These behaviours can be dramatic, resulting in significant financial and social consequences, with functional impairments, and include pathological gambling, compulsive shopping, hypersexuality, binge eating, punding (complex prolonged, purposeless, and stereotyped behaviour) and compulsive medication use. ...

Voon, V.; Mehta, Ar

2012-01-01

396

The Neurobiology and Genetics of Impulse Control Disorders: Relationships to Drug Addictions  

OpenAIRE

Impulse control disorders (ICDs), including pathological gambling, trichotillomania, kleptomania and others, have been conceptualized to lie along an impulsive-compulsive spectrum. Recent data have suggested that these disorders may be considered addictions. Here we review the genetic and neuropathological bases of the impulse control disorders and consider the disorders within these non-mutually exclusive frameworks.

Brewer, Judson A.; Potenza, Marc N.

2007-01-01

397

Isolating the delay component of impulsive choice in adolescent rats  

Directory of Open Access Journals (Sweden)

Full Text Available Impulsive choice — the preference for small immediate rewards over larger delayed rewards — has been linked to various psychological conditions ranging from behavioral disorders to addiction. These links highlight the critical need to dissect the various components of this multifaceted behavioral trait. Delay discounting tasks allow researchers to study an important factor of this behavior: how the subjective value of a rewards changes over a delay period. However, existing methods of delay discounting include a confound of modifying reward sizes during the procedure. Here we present a new approach of using a single constant reward size to assess delay discounting. A complementary approach could hold delay constant and assess the utility of changing quantities of a reward. Isolating these behavioral components can advance our ability to explore the behavioral complexity of impulsive choice. We present the methods for isolating delay in detail, and further capitalize on this method by pairing it with a standard peak interval task to test whether individual variation in delay discounting can be explained by differences in perception of time in male and female adolescent rats. We find that rats that were more precise in discriminating time intervals were also less impulsive in their choice. Our data suggest that differences in timing and delay discounting are not causally related, but instead are more likely influenced by a common factor. Further, the mean-level change in our measure between postnatal day 28 and 42 suggests this test may be capturing a developmental change in this factor. In summary, this new method of isolating individual components of impulsive choice (delay or quantity can be efficiently applied in either adolescent or adult animal models and may help elucidate the mechanisms underlying impulsivity and its links to psychological disorders.

h n r

2014-01-01

398

Electro-impulse de-icing of a turbofan engine inlet  

Science.gov (United States)

The application of electromagnetic impulse deicing (EIDI) systems to turbofan engine inlets on business aircraft has been investigated experimentally. The tests were performed in the Icing Research Tunnel at NASA's Lewis Research Center. The deicing system testbed was a Falcon Fanjet 20 engine nacelle. The effectiveness of various deicing coil configurations and mount designs were compared, and design parameters were developed specifically for EIDI systems in turbofan engines. Flight tests were also carried out at altitudes in the range 3000-6000 ft corresponding to a temperature range of -3 to -8 C. It is shown that the ice particles removed from the engine inlet by the deicing system were small enough for the engine to ingest. Tentative design specifications are given with respect to the optimum coil configuration, and operating power of a EIDI production candidate.

Zumwalt, G. W.

1985-01-01

399

Simulation Platform for Wireless Sensor Networks Based on Impulse Radio Ultra Wide Band  

CERN Document Server

Impulse Radio Ultra Wide Band (IR-UWB) is a promising technology to address Wireless Sensor Network (WSN) constraints. However, existing network simulation tools do not provide a complete WSN simulation architecture, with the IR-UWB specificities at the PHYsical (PHY) and the Medium Access Control (MAC) layers. In this paper, we propose a WSN simulation architecture based on the IR-UWB technique. At the PHY layer, we take into account the pulse collision by dealing with the pulse propagation delay. We also modelled MAC protocols specific to IRUWB, for WSN applications. To completely fit the WSN simulation requirements, we propose a generic and reusable sensor and sensing channel model. Most of the WSN application performances can be evaluated thanks to the proposed simulation architecture. The proposed models are implemented on a scalable and well known network simulator: Global Mobile Information System Simulator (GloMoSim). However, they can be reused for all other packet based simulation platforms.

Berthe, Abdoulaye; Dragomirescu, Daniela; Plana, Robert

2010-01-01

400

Global asymptotic stability analysis of bidirectional associative memory neural networks with distributed delays and impulse  

International Nuclear Information System (INIS)

Many systems existing in physics, chemistry, biology, engineering and information science can be characterized by impulsive dynamics caused by abrupt jumps at certain instants during the process. These complex dynamical behaviors can be model by impulsive differential system or impulsive neural networks. This paper formulates and studies a new model of impulsive bidirectional associative memory (BAM) networks with finite distributed delays. Several fundamental issues, such as global asymptotic stability and existence and uniqueness of such BAM neural networks with impulse and distributed delays, are established

401

Global asymptotic stability analysis of bidirectional associative memory neural networks with distributed delays and impulse  

Energy Technology Data Exchange (ETDEWEB)

Many systems existing in physics, chemistry, biology, engineering and information science can be characterized by impulsive dynamics caused by abrupt jumps at certain instants during the process. These complex dynamical behaviors can be model by impulsive differential system or impulsive neural networks. This paper formulates and studies a new model of impulsive bidirectional associative memory (BAM) networks with finite distributed delays. Several fundamental issues, such as global asymptotic stability and existence and uniqueness of such BAM neural networks with impulse and distributed delays, are established.

Huang Zaitang [Department of Mathematics, GuangXi Normal University, GuiLin 541004 (China); Luo Xiaoshu [Department of Physics and Electronic Science, GuangXi Normal University, GuiLin 541004 (China)]. E-mail: lxs@mailbox.gxun.edu.cn; Yang Qigui [School of Mathematical Sciences, South China University of Technology, GuangZhou 510640 (China)

2007-11-15

402

Analysis and design for unified exponential stability of three different impulsive T-S fuzzy systems  

International Nuclear Information System (INIS)

Three different forms of impulsive T-S models are discussed in this paper; the first one is described by a nonlinear impulsive control system represented by T-S model, while the second one is expressed as a state feedback impulsive control plant and the third one is depicted by a hybrid system. A simple and unified Lyapunov-based stability criterion is proposed to guarantee the exponential stability of closed-loop impulsive fuzzy systems. Such criterion is expressed in the form of linear matrix inequalities and the corresponding design algorithms are presented. Several numerical simulations are shown to demonstrate how the proposed controllers can stabilize these impulsive fuzzy systems.

403

Minimal Nonnegative Solution of Nonlinear Impulsive Differential Equations on Infinite Interval  

Directory of Open Access Journals (Sweden)

Full Text Available The cone theory and monotone iterative technique are used to investigate the minimal nonnegative solution of nonlocal boundary value problems for second-order nonlinear impulsive differential equations on an infinite interval with an infinite number of impulsive times. All the existing results obtained in previous papers on nonlocal boundary value problems are under the case of the boundary conditions with no impulsive effects or the boundary conditions with impulsive effects on a finite interval with a finite number of impulsive times, so our work is new. Meanwhile, an example is worked out to demonstrate the main results.

Feng Meiqiang

2011-01-01

404

A scalable piezoelectric impulse-excited energy harvester for human body excitation  

International Nuclear Information System (INIS)

Harvesting energy from low-frequency and non-harmonic excitations typical of human motion presents specific challenges. While resonant devices do have an advantage in environments where the excitation frequency is constant, and while they can make use of the entire proof mass travel range in the case of excitation amplitudes that are smaller than the internal displacement limit, they are not suitable for body applications since the frequencies are random and the amplitudes tend to be larger than the device size. In this paper a piezoelectric, impulse-excited approach is presented. A cylindrical proof mass actuates an array of piezoelectric bi-morph beams through magnetic attraction. After the initial excitation these transducers are left to vibrate at their natural frequency. This increases the operational frequency range as well as the electromechanical coupling. The principle of impulse excitation is discussed and a centimetre-scale functional model is introduced as a proof of concept. The obtained data show the influence of varying the frequency, acceleration and proof mass. Finally, a commercially available integrated circuit for voltage regulation is tested. At a frequency of 2 Hz and an acceleration of 2.7 m s?2 a maximal power output of 2.1 mW was achieved. (paper)

405

Sociodemographic, neuropsychiatric and cognitive characteristics of pathological gambling and impulse control disorders NOS in Parkinson's disease.  

Science.gov (United States)

Despite of previous evidence supporting the association between impulse control disorder (ICD) and several demographic, clinical and therapeutic features in Parkinson's disease (PD), the relationships between pathological gambling (PG) or other variants of ICD (ICD-NOS) and specific neuropsychiatric or cognitive domains are not entirely defined. In this study, 155 PD patients without dementia or cognitive impairment underwent: i. the ICD diagnoses, using the Questionnaire for Impulsive-Compulsive Disorders, ii. the mood and anxiety disorders diagnoses, according to the DSM-IV-TR criteria, and iii. a comprehensive battery for measuring severity of psychopathology and neuropsychology domains. Patients were divided in those with pathological gambling (PG), ICDs not otherwise specified (ICD-NOS), or the lack of ICD (No-ICD). There was a progression in age and age at onset from the younger PG subjects throughout ICD-NOS to No-ICD. PG and ICD-NOS subjects had longer disease duration and were taking significantly higher dosages of antiparkinsonian drugs than No-ICD ones. PG subjects had significantly higher severity of depressive and anxious symptoms with respect to the other 2 groups. Both PG and ICD-NOS subjects suffer from increased severity of psychotic symptoms than No-ICD ones. The 3 groups did not differ in any cognitive measure. Our results support the concept that the different sociodemographic and neuropsychiatric profiles of PD patients are associated with different ICDs. Moreover, we clearly demonstrate the lack of relationship between ICD and cognitive performances in undemented PD patients. PMID:25435085

Pontieri, Francesco E; Assogna, Francesca; Pellicano, Clelia; Cacciari, Claudia; Pannunzi, Sara; Morrone, Annalucia; Danese, Emanuela; Caltagirone, Carlo; Spalletta, Gianfranco

2015-01-01

406

Rapid Vaporization of Thin Conductors Used for Impulse Metalworking  

Science.gov (United States)

Forming, cutting and welding of metal by impulse has significant advantages, in that short time scales change the fundamental nature of the forming process and short duration impulses can be used with much lighter and more agile equipment because large static forces do not need to be resisted. Impulse metalworking is commonly implemented using explosives or electromagnetic actuators. Explosives have limitations such as space requirements, handling and storage restrictions and ability to scale down the process. The application of electromagnetic forming is limited at high energies and large numbers of operations by the availability of long-lived electromagnetic coils (or actuators, as they are sometimes referred to). Here low-cost, disposable actuators have been suggested as one method to treat this issue. Forming, cutting and welding of metal by impulse has significant advantages, in that short time scales change the fundamental nature of the forming process and short duration impulses can be used with much lighter and more agile equipment because large static forces do not need to be resisted. Impulse metalworking is commonly implemented using explosives or electromagnetic actuators. Explosives have limitations such as space requirements, handling and storage restrictions and ability to scale down the process. The application of electromagnetic forming is limited at high energies and large numbers of operations by the availability of long-lived electromagnetic coils (or actuators, as they are sometimes referred to). Here low-cost, disposable actuators have been suggested as one method to treat this issue. Applications including cutting, forming, axisymmetric joining and collision welding are demonstrated and discussed. From analysis of the data from these applications, it was seen that degree of confinement has a great effect on effective geometries of a vaporizing foil. With less confinement, thicker foils were found to be more efficient whereas thinner foils were found to be more effective for the applications which require less confinement pressure on the foil. Collision welding of a wide range of dissimilar metals was implemented and mechanical testing yielded a wide spectrum of results. Optical micrographs of the weld interfaces also showed a wide range of morphology. A device called linear perforator has been created to use the pressure created by vaporizing wire and detonation of a chemical augment surrounding it, to launch a 3.174 mm thick, 25.4 mm tall and 152.4 mm long steel projectile to velocities close to 400 m/s. This projectile is used to fully penetrate 12.7 mm thick artillery shells made of steel. Design of the linear perforator and latest results will be discussed.

Vivek, Anupam

407

Investigation of impulsivity in a sample of treatment-seeking pathological gamblers: a multidimensional perspective.  

Science.gov (United States)

Numerous studies have shown that problem gambling is characterised by lack of impulse control. However, they have often been conducted without considering the multifaceted nature of impulsivity and related psychological mechanisms. The current study aims to disentangle which impulsivity facets are altered in pathological gambling. Twenty treatment-seeking pathological gamblers (PGs) and 20 matched control participants completed a self-reported questionnaire measuring the various facets of impulsive behaviours (UPPS Impulsive Behaviour Scale), as well as two laboratory tasks assessing inhibitory control (the go-stop task) and tolerance for delayed rewards (single key impulsivity paradigm). Compared with matched controls, PGs exhibited higher urgency, lower premeditation, impairment in prepotent inhibition, and lower tolerance towards delayed rewards. Nevertheless, complementary profile analyses showed that impulsivity-related deficits found in PGs are highly heterogeneous, and that some PGs are neither impulsive in the impulsivity facets assessed nor impaired in the cognitive mechanisms measured. These findings underscore (1) the necessity to disentangle the construct of impulsivity into lower-order components and (2) that further studies should take into account, in addition to impulsivity-related mechanisms, other psychological factors potentially involved in pathological gambling. PMID:22421073

Billieux, Joël; Lagrange, Guillaume; Van der Linden, Martial; Lançon, Christophe; Adida, Marc; Jeanningros, Régine

2012-07-30

408

Stability of delayed memristive neural networks with time-varying impulses.  

Science.gov (United States)

This paper addresses the stability problem on the memristive neural networks with time-varying impulses. Based on the memristor theory and neural network theory, the model of the memristor-based neural network is established. Different from the most publications on memristive networks with fixed-time impulse effects, we consider the case of time-varying impulses. Both the destabilizing and stabilizing impulses exist in the model simultaneously. Through controlling the time intervals of the stabilizing and destabilizing impulses, we ensure the effect of the impulses is stabilizing. Several sufficient conditions for the globally exponentially stability of memristive neural networks with time-varying impulses are proposed. The simulation results demonstrate the effectiveness of the theoretical results. PMID:25206936

Qi, Jiangtao; Li, Chuandong; Huang, Tingwen

2014-10-01

409

Medium-frequency impulsive-thrust-activated liquid hydrogen reorientation with Geyser  

Science.gov (United States)

Efficient technique are studied for accomplishing propellant resettling through the minimization of propellant usage through impulsive thrust. A comparison between the use of constant-thrust and impulsive-thrust accelerations for the activation of propellant resettlement shows that impulsive thrust is superior to constant thrust for liquid reorientation in a reduced-gravity environment. This study shows that when impulsive thrust with 0.1-1.0-, and 10-Hz frequencies for liquid-fill levels in the range between 30-80 percent is considered, the selection of 1.0-Hz-frequency impulsive thrust over the other frequency ranges of impulsive thrust is the optimum. Characteristics of the slosh waves excited during the course of 1.0-Hz-frequency impulsive-thrust liquid reorientation were also analyzed.

Hung, R. J.; Shyu, K. L.

1992-01-01

410

Experimental single-impulse magnetic focusing of launched cold atoms  

CERN Document Server

Three-dimensional magnetic focusing of cold atoms with a single magnetic impulse has been observed for the first time. We load 7x10^7 85-Rb atoms into a magneto-optical trap, precool the atoms with optical molasses, then use moving molasses to launch them vertically through 20.5cm to the apex of flight. In transit the atoms are optically pumped, prior to the single magnetic lens impulse that occurs 16.5cm above the MOT. Fluorescence images at the apex of flight characterise the widths of the focussed cloud. Results were obtained for four different configurations of the baseball lens, which tuned the relationship between the axial and radial frequencies of the lens. Compact focused clouds were seen for all four configurations.

Smith, D A; Hughes, I G; Pritchard, M J; Arnold, Aidan S.; Hughes, Ifan G.; Pritchard, Matthew J.; Smith, David A.

2007-01-01

411

Divergent impulsive cross flow over packed columnar arrays  

International Nuclear Information System (INIS)

A quasi-one-dimensional method was devised for calculating transient, compressible, viscous flows through packet beds and over tube bundles. The method was applied to study the impulsive crossflow of a lithium plasma through an array of liquid jets, a problem that arises in the design of inertial confinement fusion reactors. The jet array was a close-packed annular arrangement with the plasma initially contained within the annular cavity so that the flow was cylindrically divergent. It was found that the crosswise momentum imparted to the jets by the plasma derived mainly from form or profile drag and that skin friction effects were negligible. Plasma drag was estimated to contribute about 20% of the total radial impulse resulting from the pellet microexplosion. (orig.)

412

Impulsive Spot Heating and Thermal Explosion of Interstellar Grains Revisited  

CERN Document Server

The problem of impulsive heating of dust grains in cold, dense interstellar clouds is revisited theoretically, with the aim to better understand leading mechanisms of the explosive desorption of icy mantles. It is rigorously shown that if the heating of a reactive medium occurs within a sufficiently localized spot (e.g., heating of mantles by cosmic rays), then the subsequent thermal evolution is characterized by a single dimensionless number $\\lambda$. This number identifies a bifurcation between two distinct regimes: When $\\lambda$ exceeds a critical value (threshold), the heat equation exhibits the explosive solution, i.e., the thermal (chemical) explosion is triggered. Otherwise, thermal diffusion causes the deposited heat to spread over the entire grain -- this regime is commonly known as the whole-grain heating. The theory allows us to find a critical combination of the physical parameters that govern the explosion of icy mantles due to impulsive spot heating. In particular, the calculations suggest tha...

Ivlev, A V; Vasyunin, A; Caselli, P

2015-01-01

413

Review of Impulse Noise Removal from Digital Video  

Directory of Open Access Journals (Sweden)

Full Text Available With the advancement in communication and information technology, legacy system are replaced by high speed computer as a result of this the world is shifting from analog to digital systems. Now, it is possible to transmit the digital videos over a communication channel and vice versa. Color video processing systems are used for a variety of purposes ranging from capturing scenes, processing of frames for feature extraction etc. Digital videos are generally contaminated by noise. Impulse noise is one such noise which may corrupt the frames of a digital video during acquisition, transmission over a noisy channel or in storage etc. This paper discussed in details about the color video processing and various schemes for removal of impulse noise for digital video.

RAVINDRA LUHACH

2013-06-01

414

Simulation Analysis and Design for the Pressure Impulse Test  

Directory of Open Access Journals (Sweden)

Full Text Available The pressure impulse test system is a complex nonlinear system; its control methods are very different from the traditional linear systems. The difficulty of its analysis focused on the physical realization of the entire system and mathematical model on complex pipeline system. We analyze the composition and principles of the entire test system, detailed study the basic equation of unsteady flow and do the static design which provides parameters for the dynamic simulation. Method of characteristics is used to establish the mathematical model. Then we analyze the transient process of the test system with the model, main analyze the affecting factors of water hammer wave-shaped through simulation. Finally, verify the correctness of simulation analysis model and ensure the impulse test can be successfully completed through the test of our main specimen -retractable actuator of landing gear with different combinations of key parameters.

Yuan Zhaohui

2012-01-01

415

Chaos and its control in an impulsive differential system  

International Nuclear Information System (INIS)

In this paper, the existence of chaos and its control in an autonomous impulsive differential system are discussed both theoretically and numerically. The existence of a snap-back repeller, as well as the chaos in the sense of Li-Yorke, is proved based on the qualitative analysis using the Poincare map and the Lambert W-function. Moreover, the existence of the period-3 periodic window embedded in the chaotic region is also demonstrated. An algorithm of chaos control to stabilize the unstable periodic solutions is proposed. Detailed numerical results of chaotic attractors and stabilization of unstable periodic orbits by the impulsive effects, which are illustrated by an example, are in good agreement with the theoretical analysis

416

Calculation of reactivity using a finite impulse response filter  

International Nuclear Information System (INIS)

A new formulation is presented in this paper to solve the inverse kinetics equation. This method is based on the Laplace transform of the point kinetics equations, resulting in an expression equivalent to the inverse kinetics equation as a function of the power history. Reactivity can be written in terms of the summation of convolution with response to impulse, characteristic of a linear system. For its digital form the Z-transform is used, which is the discrete version of the Laplace transform. This new method of reactivity calculation has very special features, amongst which it can be pointed out that the linear part is characterized by a filter named finite impulse response (FIR). The FIR filter will always be, stable and non-varying in time, and, apart from this, it can be implemented in the non-recursive form. This type of implementation does not require feedback, allowing the calculation of reactivity in a continuous way

417

Removing Impulse Bursts from Images by Training-Based Filtering  

Directory of Open Access Journals (Sweden)

Full Text Available The characteristics of impulse bursts in remote sensing images are analyzed and a model for this noise is proposed. The model also takes into consideration other noise types, for example, 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 these techniques can provide an effective removal of impulse bursts. At the same time, other noise types in images, for example, the multiplicative noise, can be suppressed without compromising good edge and detail preservation. Numerical simulation results, as well as examples of real remote sensing images, are presented.

Pertti Koivisto

2003-03-01

418

Fuzzy Impulsive Control of Permanent Magnet Synchronous Motors  

Science.gov (United States)

The permanent magnet synchronous motors (PMSMs) may experience chaotic behaviours with systemic parameters falling into a certain area or under certain working conditions, which threaten the secure and stable operation of motor-driven. Hence, it is important to study the methods of controlling or suppressing chaos in PMSMs. In this work, the Takagi-Sugeno (T-S) fuzzy impulsive control model for PMSMs is established via the T-S modelling methodology and impulsive technology. Based on the new model, the control conditions of asymptotical stability and exponential stability for PMSMs have been derived by the Lyapunov method. Finally, an illustrated example is also given to show the effectiveness of the obtained results.

Li, Dong; Wang, Shi-Long; Zhang, Xiao-Hong; Yang, Dan; Wang, Hui

2008-02-01

419

Impulse approximation in the np?d?0 reaction reexamined  

International Nuclear Information System (INIS)

The impulse approximation (one-body operator) in the np?d?0 reaction is reexamined with emphasis on the issues of reducibility and recoil corrections. An inconsistency when one-pion exchange is included in the production operator is demonstrated and then resolved via the introduction of 'wave function corrections' which nearly vanish for static nucleon propagators. Inclusion of the recoil corrections to the nucleon propagators is found to change the magnitude and sign of the impulse production amplitude, worsening agreement with the experimental cross section by ?30%. A cutoff is used to account for the phenomenological nature of the external wave functions and is found to have a significant impact for ? < or approx. 2.5 GeV.

420

Video game therapy for emotional regulation and impulsivity control in a series of treated cases with bulimia nervosa.  

Science.gov (United States)

Although standard psychological treatments have been successful in treating several core features in eating disorders (ED), other characteristics such as emotional regulation or impulsivity appear to be more resistant to change. There is a growing body of evidence to support the efficacy of cognitive remediation for cognitive and emotional difficulties in ED. Playmancer/ Islands is a video game (VG) designed to specifically treat mental disorders, characterized by problems in impulse control. The objective of the game is to increase self-control over emotions, decision making and behaviours. The aim of this study is to describe the results from a consecutive series of nine bulimia nervosa patients who were treated with the VG in addition to cognitive behaviour therapy (CBT). The outcomes included clinical and psychopathological questionnaires, and physiological measures were obtained during the VG. Emotional regulation improved, heart rate variability increased, and respiratory rate and impulsivity measures reduced after the treatment. These findings suggest that VG training may enhance treatment for ED. PMID:24092598

Fagundo, Ana B; Santamaría, Juan J; Forcano, Laura; Giner-Bartolomé, Cristina; Jiménez-Murcia, Susana; Sánchez, Isabel; Granero, Roser; Ben-Moussa, Maher; Magnenat-Thalmann, Nadia; Konstantas, Dimitri; Lam, Tony; Lucas, Mikkel; Nielsen, Jeppe; Bults, Richard G A; Tarrega, Salomé; Menchón, José M; de la Torre, Rafael; Cardi, Valentina; Treasure, Janet; Fernández-Aranda, Fernando

2013-11-01

421

The impulsive and gradual phases of a solar limb flare as observed from the solar maximum mission satellite  

International Nuclear Information System (INIS)

Simultaneous observations of a solar limb flare in the X-ray and ultraviolet regions of the spectrum are presented. Temporal and spectral X-ray observations were obtained for the 25-300 keV range while temporal, spectral, and spatial X-ray observations were obtained for the 30-0.3 keV range. The ultraviolet observations were images with a 10'' spatial resolution in the lines of O v (Tsub(e) approx. equal to 2.5 x 105 K) and Fe XXI (Tsub(e) approx. equal to 1.1 x 107 K). The hard X-ray and O v data indicate that the impulsive phase began in the photosphere or chromosphere and continued for several minutes as material was ejected into the corona. Impulsive excitation was observed up to 30,000 km above the solar surface at specific points in the flare loop. The Fe XXI observations indicate a preheating before the impulsive phase and showed the formation of hot post-flare loops. This later formation was confirmed by soft X-ray observations. These observations provide limitations for current flare models and will provide the data needed for initial conditions in modeling the concurrent coronal transient. (orig.)

422

Volatility impulse response functions for multivariate GARCH models  

OpenAIRE

In the empirical analysis of financial time series, multivariate GARCH models have been used in various forms. As it is typical for nonlinear models there is yet no unique framework available to uncover dynamic covariance relationships for vector return processes. We introduce a new concept of impulse response functions tracing the effects of independent shocks on volatility through time. The advocated methodology avoids typical orthogonalization and ordering problems. Theoretical properties ...

Hafner, Christian; Herwatz, Helmut

2001-01-01

423

Neutrino-nucleus cross section in the impulse approximation regime  

OpenAIRE

In the impulse approximation regime the nuclear response to a weakly interacting probe can be written in terms of the measured nucleon structure fuctions and the target spectral function, yielding the energy and momentum distribution of the constituent nucleons. We discuss a calculation of charged current neutrino-oxygen interactions in the quasielastic channel, carried out within nuclear many body theory. The proposed approach, extensively and successfully employed in the a...

Benhar, Omar; Farina, Nicola

2004-01-01

424

Approximation of Nonnegative Systems by Finite Impulse Response Convolutions  

OpenAIRE

We pose the deterministic, nonparametric, approximation problem for scalar nonnegative input/output systems via finite impulse response convolutions, based on repeated observations of input/output signal pairs. The problem is converted into a nonnegative matrix factorization with special structure for which we use Csisz\\'ar's I-divergence as the criterion of optimality. Conditions are given, on the input/output data, that guarantee the existence and uniqueness of the minimum...

Finesso, Lorenzo; Spreij, Peter

2013-01-01

425

A New Approach to Impulsive Rendezvous near Circular Orbit  

OpenAIRE

A new approach is presented for the problem of optimal impulsive rendezvous of a spacecraft in an inertial frame near a circular orbit in a Newtonian gravitational field. The total characteristic velocity to be minimized is replaced by a related characteristic-value function and this related optimization problem can be solved in closed form. The solution of this problem is shown to approach the solution of the original problem in the limit as the boundary conditions approach...

Carter, Thomas; Humi, Mayer

2012-01-01

426

Impulsive Ejection of Gas In Bipolar Planetary Nebulae  

OpenAIRE

We simulate the formation of bipolar planetary nebulae (PNe) through very short impulsive mass ejection events from binary systems, where the asymptotic giant branch (AGB) star ejects a mass shell that is accelerated by jets launched from a compact companion. The acceleration process takes place at very short distances from the binary system, such that the photon-diffusion time is long enough to prevent rapid cooling of the shocked jets' material. When the shocked jets' gas ...

Akashi, Muhammad; Soker, Noam

2013-01-01

427

Almost Periodic Solutions for Impulsive Fractional Stochastic Evolution Equations  

Directory of Open Access Journals (Sweden)

Full Text Available In this paper, we consider the existence of square-mean piecewise almost periodic solutions for impulsive fractional stochastic evolution equations involving Caputo fractional derivative. The main results are obtained by means of the theory of operators semi-group, fractional calculus, fixed point technique and stochastic analysis theory and methods adopted directly from deterministic fractional equations. Some known results are improved and generalized.

Toufik Guendouzi

2014-08-01

428

Eroding ribbon thermocouples: impulse response and transient heat flux analysis  

OpenAIRE

We have investigated a particular type of fast-response surface thermocouple to determine if it is appropriate to use a one-dimensional transient heat conduction model to derive the transient surface heat flux from the measurements of surface temperature. With these sensors, low thermal inertia thermocouple junctions are formed near the surface by abrasive wear. Using laser excitation, we obtained the impulse response of these commercially available devices. The response of particular sensors...

Buttsworth, Dr; Stevens, R.; Stone, Cr

2005-01-01

429

DETECTION OF LANDMINES USING IMPULSE GROUND PENETRATING RADAR  

OpenAIRE

Landmines are affecting the lives and livelihood of millions of people around the world. In this paper, we presentThe video impulse ground penetrating radar system for detection for small and shallow buried objects has been developed. The hardware combines commercially available components with components specially developed or modified for being used in the system. The GPR system has been desired to measure accurately electromagnetic field backscattered from subsurface targets in order to al...

RAMAKRISHNA PORANDLA; PODILI RAMU; GELLA RAVIKANTH

2013-01-01

430

Problems Related to Bootstrapping Impulse Responses of Autoregressive Processes  

OpenAIRE

Bootstrap confidence intervals for impulse responses computed from autoregressive processes are considered. A detailed analysis of the methods in current use shows that they are not very reliable in some cases. In particular, there are theoretical reasons for them to have actual coverage probabilities which deviate considerably from the nominal level in some situations of practical importance. For a simple case alternative bootstrap methods are proposed which provide correct results asymptoti...

Benkwitz, Alexander; Lu?tkepohl, Helmut; Neumann, Michael H.

1997-01-01

431

Stage-Structured Impulsive SI Model for Pest Management  

OpenAIRE

An SI epidemic model with stage structure is investigated. In the model, impulsive biological control is taken, that is, we release infected pests to the field at a fixed time periodically. We get a sufficient condition for the global asymptotical stability of the pest-eradication periodic solution (0,0,I˜(t)), and a condition for the permanence of the system. At last, a brief discussion shows that our results will be helpful for pest management.

Lansun Chen; Ruiqing Shi

2008-01-01

432

Stage-Structured Impulsive SI Model for Pest Management  

Directory of Open Access Journals (Sweden)

Full Text Available An SI epidemic model with stage structure is investigated. In the model, impulsive biological control is taken, that is, we release infected pests to the field at a fixed time periodically. We get a sufficient condition for the global asymptotical stability of the pest-eradication periodic solution (0,0,I˜(t, and a condition for the permanence of the system. At last, a brief discussion shows that our results will be helpful for pest management.

Lansun Chen

2008-01-01

433

Isolating the delay component of impulsive choice in adolescent rats  

OpenAIRE

Impulsive choice — the preference for small immediate rewards over larger delayed rewards — has been linked to various psychological conditions ranging from behavioral disorders to addiction. These links highlight the critical need to dissect the various components of this multifaceted behavioral trait. Delay discounting tasks allow researchers to study an important factor of this behavior: how the subjective value of a rewards changes over a delay period. However, existing methods of de...

h n r

2014-01-01

434

On Heat and Paper : From Hot Pressing to Impulse Technology  

OpenAIRE

Impulse technology is a process in which water is removedfrom a wet paper web by the combined action of mechanicalpressure and intense heat. This results in increased dewateringrates, increased smoothness on the roll side of the sheet, andincreased density. Although the potential benefits of impulsepressing have been debated over the past thirty years, itsindustrial acceptance has been prevented by web delamination,which is defined as a reduction in the z-directional strengthof paper. This th...

Lucisano, Marco Francesco Carlo

2002-01-01

435

An Impulse Response Function for Evaluation of UWB SAR Imaging  

OpenAIRE

Based on analysis of a point target imaged by different synthetic aperture radar (SAR) systems, the commonly used impulse response function in SAR Imaging (IRF-SAR)—a two-dimensional (2-D) sinc function—is shown to be inappropriate for ultrawideband-ultrawidebeam (UWB) SAR systems utilizing a large fractional signal bandwidth and a wide antenna beamwidth. As a consequence, the applications of the 2-D sinc function such as image quality measurements and spatial reso...

Vu, Viet; Sjo?gren, Thomas; Pettersson, Mats; Hellsten, Hans

2010-01-01

436

Simulation Analysis and Design for the Pressure Impulse Test  

OpenAIRE

The pressure impulse test system is a complex nonlinear system; its control methods are very different from the traditional linear systems. The difficulty of its analysis focused on the physical realization of the entire system and mathematical model on complex pipeline system. We analyze the composition and principles of the entire test system, detailed study the basic equation of unsteady flow and do the static design which provides parameters for the dynamic simulation. Method of character...

Yuan Zhaohui; Zhao Kaiyu

2012-01-01

437

Damage Analysis of 3D Frame Structure under Impulsive Load  

OpenAIRE

In this article, we utilized the lumped damage mechanics method to implement the damage analysis to the 3D frame structure under impulsive load. First, take the damage parameters as the interior variable of the system, and based on the finite unit, combine continuum mechanics, fracture mechanics and plastic hinge to analyze the mechanical behaviors of the structure, and finally implement numerical simulation analysis to the frame structure with two layers, and compare the result with the comp...

Wenzhao Fan; Julin Wang; Liming Gao; Shougao Tang

2009-01-01

438

Rapid-response impulsivity: Definitions, measurement issues, and clinical implications.  

Science.gov (United States)

Impulsivity is a multifaceted construct that is a core feature of multiple psychiatric conditions and personality disorders. However, progress in understanding and treating impulsivity is limited by a lack of precision and consistency in its definition and assessment. Rapid-response impulsivity (RRI) represents a tendency toward immediate action that occurs with diminished forethought and is out of context with the present demands of the environment. Experts from the International Society for Research on Impulsivity (InSRI) met to discuss and evaluate RRI measures in terms of reliability, sensitivity, and validity, with the goal of helping researchers and clinicians make informed decisions about the use and interpretation of findings from RRI measures. Their recommendations are described in this article. Commonly used clinical and preclinical RRI tasks are described, and considerations are provided to guide task selection. Tasks measuring two conceptually and neurobiologically distinct types of RRI, "refraining from action initiation" (RAI) and "stopping an ongoing action" (SOA) are described. RAI and SOA tasks capture distinct aspects of RRI that may relate to distinct clinical outcomes. The InSRI group recommends that (a) selection of RRI measures should be informed by careful consideration of the strengths, limitations, and practical considerations of the available measures; (b) researchers use both RAI and SOA tasks in RRI studies to allow for direct comparison of RRI types and examination of their associations with clinically relevant measures; and (c) similar considerations be made for human and nonhuman studies in an effort to harmonize and integrate preclinical and clinical research. (PsycINFO Database Record PMID:25867840

Hamilton, Kristen R; Littlefield, Andrew K; Anastasio, Noelle C; Cunningham, Kathryn A; Fink, Latham H L; Wing, Victoria C; Mathias, Charles W; Lane, Scott D; Schütz, Christian G; Swann, Alan C; Lejuez, C W; Clark, Luke; Moeller, F Gerard; Potenza, Marc N

2015-04-01

439

Method and apparatus for improved high power impulse magnetron sputtering  

Science.gov (United States)

A high power impulse magnetron sputtering apparatus and method using a vacuum chamber with a magnetron target and a substrate positioned in the vacuum chamber. A field coil being positioned between the magnetron target and substrate, and a pulsed power supply and/or a coil bias power supply connected to the field coil. The pulsed power supply connected to the field coil, and the pulsed power supply outputting power pulse widths of greater that 100 .mu.s.

Anders, Andre

2013-11-05

440

Measurement setup for High Power Impulse Magnetron Sputtering  

OpenAIRE

Recently material physics group at Science Institute of University of Iceland has been using reactive sputtering to grow thin films used in various research projects at the institute. These films have been grown using dc sputtering which has been proven a very successful method. High power impulse magnetron sputtering or HiPIMS is an new pulsed power sputtering method where shorter but high power pulses are used to sputter over lower steady power. The project resulted in a functional system c...

Sveinsson, O?lafur Bjo?rgvin

2011-01-01

441

Static and dynamic analysis of impulse gas seal  

OpenAIRE

Impulse seal is the type of non-contacting seal. Work of seal is based on the creation of a high-frequency pulse pressure in handling the cells. In this case it receives the name of pulsed compaction. It consists of an axially movable ring, closed chambers, a rotating wear band and radial feeders. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/34841

Khalizeva, A. G.

2014-01-01

442

Protocols for Impulse Radio UWB Ad Hoc Networks :  

OpenAIRE

Ultra Wideband (UWB) technology offers an unprecedented opportunity to further accelerate the evolution of wireless communication and expand the application landscape by enabling outstanding capabilities. UWB radio is fundamentally different from most radio technologies, e.g., Bluetooth, WLAN, etc. UWB has many forms. A promising but, not well explored form is single-band impulse radio UWB (IR-UWB). In IR-UWB data is transmitted by using a series of very narrow pulses rather than by modulatin...

Shi, N.

2010-01-01

443

Subtyping pathological gamblers based on impulsivity, depression and anxiety  

OpenAIRE

This study examined putative subtypes of pathological gamblers (PGs) based on the Pathways Model, and it also evaluated whether the subtypes would benefit differentially from treatment. Treatment-seeking PGs (N = 229) were categorized into Pathways subtypes based on scores from questionnaires assessing anxiety, depression and impulsivity. The Addiction Severity Index Gambling assessed severity of gambling problems at baseline, post-treatment and 12-month follow-up. Compared with Behaviorally ...

Ledgerwood, David M.; Petry, Nancy M.

2010-01-01

444

Venous impulse foot pumps: should graduated compression stockings be used?  

OpenAIRE

It is not known whether the effect of Foot Pumps (Novamedix, Andover, UK) is enhanced by simultaneous use of graduated compression stockings (by controlling calf compliance) or hindered (by restricting preload). To address this question, we studied 20 healthy volunteers with duplex ultrasound. The peak velocity in the popliteal vein was measured at rest with the legs flat, foot-up, and foot-down, then it was measured when the AV Impulse Foot Pump was activated. These measurements each were pe...

Warwick, Dj; Pandit, H.; Shewale, S.; Sulkin, T.

2002-01-01

445

Sparse representation of channel's impulse response for underwater inhomogeneities tracking  

OpenAIRE

In this paper, we propose a method for underwater inhomogeneities characterization using sparse representation of channel's impulse response. We consider the case of moving vortices created naturally or artificially that do not conserve their physical properties when observed at two distinct positions in space. Existing amplitude-based techniques fail to provide an accurate representation when the physical properties of the dynamic inhomogeneity are altered, but it can be achieved using the d...

Candel, Ion; Bernard, Cindy; Ioana, Cornel; Reeb, Bertrand; Boldo, Didier

2013-01-01

446

Impulse Volt-Time Characteristics of Oil and OIP Insulation  

OpenAIRE

Estimation of insulation strength of transformer oil and Oil Impregnated Paper (OIP) insulation, which constitutes major portion of insulation in power transformer, is an important task. Also, it is often necessary to evaluate the breakdown strength of oil and OIP under non-standard impulse voltages, since the oil and OIP insulation is subjected to non-standard waveshapes between inter-disc and inter-turn insulation. This necessitates for a generalized model to estimate th...

Venkatesan, S.; Usa, S.

2005-01-01

447

SSICM (Spin Stabilized Impulsively Controlled Missile) guidance and control concept  

Science.gov (United States)

The guidance scheme utilizing wide beam width semiactive RF sensors, a precision roll attitude reference, and a controlled grade pitch, yaw and roll rate gyros to deliver high quality homing guidance information to a spin stabilized controlled missile is presented. A filtering system is utilized to eliminate errors caused by body roll signals generated due to the spin of the missiles. The nutational motion is used to calibrate the sensors. Impulsive maneuvers are utilized to intercept incoming ballistic targets.

Howell, W. M.

1985-09-01

448

Planar elliptically shaped dipole antenna for UWB Impulse Radio:  

OpenAIRE

The goal of this thesis was to develop design concepts of the UWB antenna with improved characteristics for impulse radio applications. To reach this goal a number of theoretical and experimental investigations were carried out. The major result of the thesis is a number of novel concepts for UWB antennas including: - The shielded elliptically-shaped dipole; - The active UWB antenna with an integrated pulse generator on chip; - The differential feeding of balanced UWB antennas via a shie...

Vorobyov, A. V.

2008-01-01

449

Efficient Techniques for Denoising of Highly Corrupted Impulse Noise Images  

OpenAIRE

In this paper, different types of impulse noiseremoval techniques are presented. Because of adaptive nature ofmask size depending on the noise quantity in the image, adaptivemedian filter works better in removing the salt and pepper noise.To show the performance of Adaptive Median filter, median filter,Lee filter, Frost and Kuan filters and DWT and Duqal treeComplex Wavelet Transform are considered. Adaptive medianfilter is compared with other filters and also the transformations.The superior...

Suresh Velaga; Sridhar Kovvada

2012-01-01

450

Study and Analysis of Impulse Noise Reduction Filters  

OpenAIRE

In this paper, a new Decision Based median filtering algorithm is presented for the removal ofimpulse noise from digital images. Here, we replace the impulse noise corrupted pixel by the median of thepixel scanned in four directions.The signal restoration scheme of this filter adapts to the varied impulsenoise ratios while determining an appropriate signal restorer from a reliable neighbourhood. Theexperimental results of this filter applied on various images corrupted with almost all ratios ...

Geoffrine Judith.M.C; Kumarasabapathy, N.

2011-01-01

451

Review of Impulse Noise Removal from Digital Video  

OpenAIRE

With the advancement in communication and information technology, legacy system are replaced by high speed computer as a result of this the world is shifting from analog to digital systems. Now, it is possible to transmit the digital videos over a communication channel and vice versa. Color video processing systems are used for a variety of purposes ranging from capturing scenes, processing of frames for feature extraction etc. Digital videos are generally contaminated by noise. Impulse noise...

RAVINDRA LUHACH; SHELEJ KHERA

2013-01-01

452

Dicke Superradiance in a magnetoplasma  

CERN Document Server

We present theoretical results for superradiance, i.e. the collective coherent decay of a radiating system, in a semiconductor heterostructure under a strong quantizing magnetic field. We predict a strong peak (`Dicke-peak') in the emission intensity as a function of time, which should be observable after a short initial excitation of electrons into the conduction band. This peak has a characteristic dependence on the magnetic field and should be observable on sub-picosecond time scales. Furthermore, pumping of electrons and holes into the systems at a rate T leads to a novel kind of oscillations with frequency

Brandes, T; Shimizu, A; Brandes, Tobias; Inoue, Jun'ichi; Shimizu, Akira

1999-01-01

453

Design of shielded voltage divider for impulse voltage measurement  

International Nuclear Information System (INIS)

The dividers used for the study of the insulation and electric discharge phenomena in high voltage equipments have the problems of the change of response characteristics owing to adjacent bodies and of induced noise. To improve the characteristics, the enclosed type divider shielded with metal has been investigated, and the divider of excellent response has been obtained by adopting the frequency-separating divider system, which is divided into two parts, resistance divider (lower frequency region) and capacitance divider (higher frequency region), for avoiding to degrade the response. Theoretical analysis was carried out in the cases that residual inductance can be neglected or can not be neglected in the small capacitance divider, and that the connecting wires are added. Next, the structure of the divider and the design of the electric field for the divider manufactured on the basis of the theory are described. The response characteristics were measured. The results show that 1 MV impulse voltage can be measured within the response time of 10 ns. Though this divider aims at the impulse voltage, the duration time of which is about that of standard lightning impulse, in view of the heat capacity because of the input resistance of 10.5 k?, it is expected that the divider can be applied to the voltage of longer duration time by increasing the input resistance in future. (Wakatsuki, Y.)

454

Evidence for collisionless conduction fronts in impulsive solar flares  

International Nuclear Information System (INIS)

Impulsive bursts of hard x-rays and microwaves are observed during most solar flares, and both emissions can be attributed to a common distribution of source electrons with energies from approximately 10 keV to several hundred keV. A detailed account of the evolution of the electron distribution is crucial to a complete description of the energy process in flares. In this paper, a new analysis is made of a thermal flare model proposed by Brown. Melrose, and Spicer; and Smith and Lilliequist. They argued that the source assumed in this model would not explain the simultaneous impulsive microwavve emissio. In contrast, the new results presented here show 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 portios 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, and c/sub s/ = (kT/sub e//m/sub i/)/sup 1/2/ is the ion-sound speed. New observations of these impulsive flare emissions are analyzed herein to test this prediction of the model

455

A New Approach to Impulsive Rendezvous near Circular Orbit  

CERN Document Server

A new approach is presented for the problem of optimal impulsive rendezvous of a spacecraft in an inertial frame near a circular orbit in a Newtonian gravitational field. The total characteristic velocity to be minimized is replaced by a related characteristic-value function and this related optimization problem can be solved in closed form. The solution of this problem is shown to approach the solution of the original problem in the limit as the boundary conditions approach those of a circular orbit. Using a form of primer-vector theory the problem is formulated in a way that leads to relatively easy calculation of the optimal velocity increments. A certain vector that can easily be calculated from the boundary conditions determines the number of impulses required for solution of the optimization problem and also is useful in the computation of these velocity increments. Necessary and sufficient conditions for boundary conditions to require exactly three nonsingular non-degenerate impulses for solution of th...

Carter, Thomas

2012-01-01

456

Fermi-LAT Observation of Impulsive Solar Flares  

CERN Document Server

The Fermi Large Area Telescope (LAT) is the most sensitive instrument ever deployed in space for observing gamma-ray emission >100 MeV. This sensitivity has enabled the LAT to detect gamma-ray emission from the Sun during quiescent periods from pions produced by cosmic-ray protons interacting in the solar atmosphere and from cosmic-ray electrons interacting with solar optical photons. The LAT has detected high-energy gamma-ray emission associated with GOES M-class and X-class X-ray flares accompanied by coronal mass ejections and solar energetic particle events. In a number of cases, LAT has detected gamma rays with energies up to several hundreds of MeV during the impulsive phase and gamma rays up to GeV energies sustained for several hours after the impulsive phase. This presentation focuses on observations in the impulsive emission phase in solar flares, including the modest GOES M2-class flare at SOL2010-06-12T0057 and more recent detections, such as the bright X-class flares of March 2012.

Omodei, N; Pesce-Rollins, M

2013-01-01

457

An Evaluation of the Impulse NTP System Core Configurations  

Science.gov (United States)

The results of a neutronic study of an Impulse reactor using cermets and carbide based fuels are presented in this paper. Earlier studies have shown that a fast reactor for an NTP system using tungsten cermet fuel eliminates the water submersion criticality problem due to the poisoning effect of the tungsten when the spectrum is thermalized by the incursion of water into the core. A thermal reactor is required to have an active shutdown system to protect against inadvertent reentry of an NTP system into Earth after having reached criticality in space. When immersed in water, the neutron flux is moderated and the tungsten becomes a strong absorber. Also, cermet fuel may have better fission products retention than the graphite based fuel elements used for a thermal reactor at the same or higher temperature. The results of the analysis demonstrated that a fast reactor version of the Impulse is feasible; however, it lends itself better to larger thrust engines than 334kN (75000 lbf). A significant increase in design margin results if the larger core Impulse is operated at only 334kN, but the thrust to weight ratio drops as a result.

Hundal, Rolv; Petrosky, Lyman J.; Zweig, Herbert R.

1994-07-01

458

Mathematical simulation of oil fields probing using shock impulse loading  

Science.gov (United States)

Capabilities of approximate mathematical modeling of the sounding oil fields with use of shock impulses are studied. To this goal, a multilayered column-waveguide extracted from a solid half-space is considered. The analysis is carried out with reference to plane waves propagating in the multilayered medium with arbitrary located layers of various rheological properties. As a source of signals both surface impulses and underwater or underground explosions, single and periodic, and also harmonious excitation are considered, and displacements of a free surface—as the response. The process of wave propagation under repeated reflections from the layer borders is computed numerically with use of the authors' wave finite element method. The amplitude-frequency spectrum of the reflected signals is analyzed both qualitatively and using an original method of "focusing". It is shown, that the analysis of the response for a shock impulse loading allows receiving sufficiently full information about layers' location and thickness. The considered approaches can be used at processing and analyzing the reflected signals obtained experimentally during investigations of oil fields.

Shorr, B. F.; Mel'nikova, G. V.; Khanyan, G. S.

2007-12-01

459

Obsessive compulsive disorder and impulse control disorder comorbidity and evaluation of impulsivity and compulsivity in alcohol dependent patients  

Directory of Open Access Journals (Sweden)

Results: There was at least one ICD in 24.6 of the alcohol dependent patients. The most commonly encountered subtype was pathological gambling (16.0 which was followed by intermittent explosive disorder (6.1 and compulsive shopping (3.7. 13.5 of the patients were diagnosed with OCD while OCD at a subclinical level was found in 19.8 of them. 46.9 of the patients presented either with "obsessive compulsive traits" or ICD or both. Conclusion: In addition to the evaluation of impulsivity and compulsivity with using scales, OCD and ICD comorbidity was investigated in alcohol dependent patients. Together with the not otherwise specified impulse control disorders, at least one ICD was found in 24.6 of the addicts while 13.5 presented with OCD comorbidity.

buket belkiz gungor

2014-01-01

460

Impulsive moving mirror model and the stability of linear homogeneous differential equations with impulse effect in a Banach space  

International Nuclear Information System (INIS)

From a special class of systems has been used the linear homogeneous differential equations with impulse effect in Minkowski space field theory with time dependent boundary conditions, i.e. those of moving mirrors. The field theoretical approach for studing the properties of the vacuum starts from an analysis of the behaviour of local field quantities in Minkowski space with uniformly moving mirrors. For the impulsive moving mirror model is the real process of interaction between the quantum field and the external mirror a subject to disturbances in its evolution acting in time very short compared with the entire duration of the process. The stability of the process in the stability of the vacuum state energy. 7 refs

461

Solar proton event archeology: impulsive nitrate enhancements in polar ice  

Science.gov (United States)

Solar proton events have been measured for the past sixty years by various techniques: e.g. neutron monitors, riometers, spacecraft instrumentation. While we have a fairly accurate record of solar proton events over five solar cycles, little is known about solar proton events that have occurred in the distant past. We have found that impulsive transient nitrate deposition events using ultra high-resolution analyses (approximately 20 samples per year) of the nitrate concentration in polar ice have