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Sample records for strongly electron withdrawing

  1. Application of Chan-Lam cross coupling for the synthesis of N-heterocyclic carbene precursors bearing strong electron donating or withdrawing groups

    Science.gov (United States)

    Huang, Liliang; He, Chengxiang; Sun, Zhihua

    2015-07-01

    Chan-Lam cross coupling allowed efficient synthesis of N,N’-disubstituted ortho-phenylene diamines bearing strong electron donating or withdrawing groups, such as nitro or methoxy groups, with moderate to high yields. These diamines can then be turned into N-heterocyclic carbene precursors after condensation with trimethyl orthoformate. The same strategy can also be utilized for the synthesis of N-monosubstituted aniline derivatives containing a functionalized ortho-aminomethyl group as intermediates for chiral 6-membered ring carbene precursors.

  2. PREFACE: Strongly correlated electron systems Strongly correlated electron systems

    Science.gov (United States)

    Saxena, Siddharth S.; Littlewood, P. B.

    2012-07-01

    This special section is dedicated to the Strongly Correlated Electron Systems Conference (SCES) 2011, which was held from 29 August-3 September 2011, in Cambridge, UK. SCES'2011 is dedicated to 100 years of superconductivity and covers a range of topics in the area of strongly correlated systems. The correlated electronic and magnetic materials featured include f-electron based heavy fermion intermetallics and d-electron based transition metal compounds. The selected papers derived from invited presentations seek to deepen our understanding of the rich physical phenomena that arise from correlation effects. The focus is on quantum phase transitions, non-Fermi liquid phenomena, quantum magnetism, unconventional superconductivity and metal-insulator transitions. Both experimental and theoretical work is presented. Based on fundamental advances in the understanding of electronic materials, much of 20th century materials physics was driven by miniaturisation and integration in the electronics industry to the current generation of nanometre scale devices. The achievements of this industry have brought unprecedented advances to society and well-being, and no doubt there is much further to go—note that this progress is founded on investments and studies in the fundamentals of condensed matter physics from more than 50 years ago. Nevertheless, the defining challenges for the 21st century will lie in the discovery in science, and deployment through engineering, of technologies that can deliver the scale needed to have an impact on the sustainability agenda. Thus the big developments in nanotechnology may lie not in the pursuit of yet smaller transistors, but in the design of new structures that can revolutionise the performance of solar cells, batteries, fuel cells, light-weight structural materials, refrigeration, water purification, etc. The science presented in the papers of this special section also highlights the underlying interest in energy-dense materials, which

  3. EDITORIAL: Strongly correlated electron systems Strongly correlated electron systems

    Science.gov (United States)

    Ronning, Filip; Batista, Cristian

    2011-03-01

    Strongly correlated electrons is an exciting and diverse field in condensed matter physics. This special issue aims to capture some of that excitement and recent developments in the field. Given that this issue was inspired by the 2010 International Conference on Strongly Correlated Electron Systems (SCES 2010), we briefly give some history in order to place this issue in context. The 2010 International Conference on Strongly Correlated Electron Systems was held in Santa Fe, New Mexico, a reunion of sorts from the 1989 International Conference on the Physics of Highly Correlated Electron Systems that also convened in Santa Fe. SCES 2010—co-chaired by John Sarrao and Joe Thompson—followed the tradition of earlier conferences, in this century, hosted by Buzios (2008), Houston (2007), Vienna (2005), Karlsruhe (2004), Krakow (2002) and Ann Arbor (2001). Every three years since 1997, SCES has joined the International Conference on Magnetism (ICM), held in Recife (2000), Rome (2003), Kyoto (2006) and Karlsruhe (2009). Like its predecessors, SCES 2010 topics included strongly correlated f- and d-electron systems, heavy-fermion behaviors, quantum-phase transitions, non-Fermi liquid phenomena, unconventional superconductivity, and emergent states that arise from electronic correlations. Recent developments from studies of quantum magnetism and cold atoms complemented the traditional subjects and were included in SCES 2010. 2010 celebrated the 400th anniversary of Santa Fe as well as the birth of astronomy. So what's the connection to SCES? The Dutch invention of the first practical telescope and its use by Galileo in 1610 and subsequent years overturned dogma that the sun revolved about the earth. This revolutionary, and at the time heretical, conclusion required innovative combinations of new instrumentation, observation and mathematics. These same combinations are just as important 400 years later and are the foundation of scientific discoveries that were discussed

  4. Polymerization catalysts containing electron-withdrawing amide ligands

    Science.gov (United States)

    Watkin, John G.; Click, Damon R.

    2002-01-01

    The present invention describes methods of making a series of amine-containing organic compounds which are used as ligands for group 3-10 and lanthanide metal compounds. The ligands have electron-withdrawing groups bonded to them. The metal compounds, when combined with a cocatalyst, are catalysts for the polymerization of olefins.

  5. Electronic Structure of Strongly Correlated Materials

    CERN Document Server

    Anisimov, Vladimir

    2010-01-01

    Electronic structure and physical properties of strongly correlated materials containing elements with partially filled 3d, 4d, 4f and 5f electronic shells is analyzed by Dynamical Mean-Field Theory (DMFT). DMFT is the most universal and effective tool used for the theoretical investigation of electronic states with strong correlation effects. In the present book the basics of the method are given and its application to various material classes is shown. The book is aimed at a broad readership: theoretical physicists and experimentalists studying strongly correlated systems. It also serves as a handbook for students and all those who want to be acquainted with fast developing filed of condensed matter physics.

  6. Nonlinear Electron Waves in Strongly Magnetized Plasmas

    DEFF Research Database (Denmark)

    Pécseli, Hans; Juul Rasmussen, Jens

    1980-01-01

    Weakly nonlinear dispersive electron waves in strongly magnetized plasma are considered. A modified nonlinear Schrodinger equation is derived taking into account the effect of particles resonating with the group velocity of the waves (nonlinear Landau damping). The possibility of including the ion...... dynamics in the analysis is also demonstrated. As a particular case the authors investigate nonlinear waves in a strongly magnetized plasma filled wave-guide, where the effects of finite geometry are important. The relevance of this problem to laboratory experiments is discussed....

  7. Electrons in a strong magnetic field

    International Nuclear Information System (INIS)

    Itzykson, C.

    1985-05-01

    We first describe the average one-particle spectrum in the presence of a strong magnetic field together with random impurities for a Gaussian distribution, and generalized using a supersymmetric method. We then study the effect of Coulomb interactions on an electron gas in a strong field, within the approximation of a projection on the lowest Landau level. At maximal density (or filling fraction ν equal to unity) the quantum mechanical problem is equivalent to a soluble classical model for a two-dimensional plasma. As ν decreases, more states come into play. Laughlin has guessed the structure of the ground state and its low lying excitations for certain rational values of the filling fraction. A complete proof is however missing, nor is it clear what happens as ν becomes so small that a ''crystalline'' structure becomes favoured. Our presentation shows a link with functions occurring in combinatorics and analytic number theory, which seems not to have been fully exploited

  8. Strongly Correlated Electron Systems: An Operatorial Perspective

    Science.gov (United States)

    Di Ciolo, Andrea; Avella, Adolfo

    2018-05-01

    We discuss the operatorial approach to the study of strongly correlated electron systems and show how the exact solution of target models on small clusters chosen ad-hoc (minimal models) can suggest very efficient bulk approximations. We use the Hubbard model as case study (target model) and we analyze and discuss the crucial role of spin fluctuations in its 2-site realization (minimal model). Accordingly, we devise a novel three-pole approximation for the 2D case, including in the basic field an operator describing the dressing of the electronic one by the nearest-neighbor spin-fluctuations. Such a solution is in very good agreement with the exact one in the minimal model (2-site case) and performs very well once compared to advanced (semi-)numerical methods in the 2D case, being by far less computational-resource demanding.

  9. Phosphorescent rhenium emitters based on two electron-withdrawing diamine ligands: Structure, characterization and electroluminescent performance

    Energy Technology Data Exchange (ETDEWEB)

    Rui, Mei, E-mail: meirui2015@163.com [College of Science, Hebei North University, Zhangjiakou 075000, Hebei (China); Yuhong, Wang [College of Science, Hebei North University, Zhangjiakou 075000, Hebei (China); Yinting, Wang; Na, Zhang [Communication Training Base of The Headquarters of The General Staff, Zhangjiakou 075100, Hebei (China)

    2014-09-15

    In this paper, two diamine ligands having electron-withdrawing oxadiazole group and their corresponding Re(I) complexes were synthesized. Their geometric structure, electronic transition, photophysical property, thermal stability and electrochemical property were discussed in detail. Experimental data suggested that both complexes were promising yellow emitters with suited energy levels and good thermal stability for electroluminescent application. The correlation between emission performance and electron-withdrawing group was analyzed. It was found that electron-withdrawing group favored emission performance improvement. Their electroluminescence performance was also explored. Yellow electroluminescence was observed with maximum brightness of 1743 cd/m{sup 2}. - Highlights: • Oxadiazole derived diamine ligands and their Re(I) complexes were synthesized. • Their characters and properties were analyzed and compared in detail. • Electron-withdrawing group was proved to be positive for PL improvement. • Electroluminescence was obtained with maximum brightness of 1743 cd/m{sup 2}.

  10. Effect of electron-withdrawing power of the substituted group on OH ...

    Indian Academy of Sciences (India)

    depending on the concentration of acid and electron-withdrawing power, solute radical cation is the only ... one anti-bonding σ* electron. ... pulse, which was close to 15 Gy (1 Gy = 1 J kg–1) except for kinetic experiments, which were carried ...

  11. Electron wind in strong wave guide fields

    Science.gov (United States)

    Krienen, F.

    1985-03-01

    The X-ray activity observed near highly powered waveguide structures is usually caused by local electric discharges originating from discontinuities such as couplers, tuners or bends. In traveling waves electrons move in the direction of the power flow. Seed electrons can multipactor in a traveling wave, the moving charge pattern is different from the multipactor in a resonant structure and is self-extinguishing. The charge density in the wave guide will modify impedance and propagation constant of the wave guide. The radiation level inside the output wave guide of the SLAC, 50 MW, S-band, klystron is estimated. Possible contributions of radiation to window failure are discussed.

  12. Strongly correlated electrons on two coupled chains

    International Nuclear Information System (INIS)

    Weihong, Z.; Oitmaa, J.; Hamer, C.J.

    2000-01-01

    Full text: The discovery of materials containing S = 1/2 ions which form a 2-leg ladder structure has led to much current research on ladder systems. Pure spin ladders show an unexpected difference between odd-legged ladders (including the single chain) which are gapless with long-range correlations and even-legged ladders which have a spin gap and short range correlations. Even more interesting behaviour occurs when these systems are doped, creating a system of strongly correlated mobile holes, as in the cuprate superconductors. The simplest models in this context are the Hubbard model and the t-J model. Considerable work has been reported on both of these models, using both numerical calculations and approximate analytic theories. We have used series expansion methods to study both of these systems. Our results, in some cases, confirm those of other approaches. In other cases we are able to probe regions of the phase diagram inaccessible to other methods, or to obtain results of increased precision. In this paper we focus on:- 1. The energy and dispersion relation of 1-hole states. 2.The existence of a 2-hole bound state and its energy and dispersion. 3. Spin and charge gaps and the question of phase separation

  13. THE CONSUMER’S RIGHT OF WITHDRAWAL FROM CONTRACTS CONCLUDED BY ELECTRONIC MEANS IN ROMANIAN LAW

    Directory of Open Access Journals (Sweden)

    MIHAELA GIURANIUC (TUDORACHE

    2011-04-01

    Full Text Available The purpose of this paper is to analyse the legislation, doctrinal opinions and relevant case law regarding the consumer's right of withdrawal from contracts concluded by electronic means (e-contracts.The objectives pursued by the author are:- establishing the juridical nature of consumer's right of withdrawal from e-contracts;- identification of problems that could arise from law’s interpretation,- issuing of the de lege ferenda proposals.Governmental Ordinance no. 130/2000 introduces a new exception to the principle of irrevocability of contracts in Romanian law: the consumer's right of withdrawal from distance contracts. The same Ordinance sets the scope and conditions for the applicability of this right.Consumer's right of withdrawal from e-contracts, as a type of distance contracts, can be exercised without the need to give any specific reason and without penalties, within 10 working days from the date of receiving the goods or from the another moment depending on the specifics set out in GO no. 130/2000. If consumer cancels the distance contract on the basis that he does not like the goods, the withdrawal from the contract is valid, even if the withdrawal solely depended on the will of the consumer, this sets out a legal exception from the provisions of art. 1010 of Civil Code which stipulate the nullity of the obligations undertook by the liable person under the condition “if I want”.Sales of goods by electronic means, as a particular case of a distance contracts, is, therefore, a new form of selling, governed by its own specific legal regime.

  14. The electronic-cigarette: effects on desire to smoke, withdrawal symptoms and cognition

    OpenAIRE

    Dawkins, Lynne; Turner, John J.D.; Hasna, Surrayyah; Soar, Kirstie

    2012-01-01

    Electronic cigarettes (e-cigarettes) are battery operated devices that deliver nicotine via inhaled vapour. Few studies have evaluated acute effects on craving and mood, and none have explored effects on cognition. This study aimed to explore the effects of the White Super e-cigarette on desire to smoke, nicotine withdrawal symptoms, attention and working memory. Eighty-six smokers were randomly allocated to either: 18mg nicotine e-cigarette (nicotine), 0mg e-cigarette (placebo), or just hold...

  15. Can Electron-Rich Oxygen (O2-) Withdraw Electrons from Metal Centers? A DFT Study on Oxoanion-Caged Polyoxometalates.

    Science.gov (United States)

    Takazaki, Aki; Eda, Kazuo; Osakai, Toshiyuki; Nakajima, Takahito

    2017-10-12

    The answer to the question "Can electron-rich oxygen (O 2- ) withdraw electrons from metal centers?" is seemingly simple, but how the electron population on the M atom behaves when the O-M distance changes is a matter of controversy. A case study has been conducted for Keggin-type polyoxometalate (POM) complexes, and the first-principles electronic structure calculations were carried out not only for real POM species but also for "hypothetical" ones whose heteroatom was replaced with a point charge. From the results of natural population analysis, it was proven that even an electron-rich O 2- , owing to its larger electronegativity as a neutral atom, withdraws electrons when electron redistribution occurs by the change of the bond length. In the case where O 2- coexists with a cation having a large positive charge (e.g., P 5+ (O 2- ) 4 = [PO 4 ] 3- ), the gross electron population (GEP) on the M atom seemingly increases as the O atom comes closer, but this increment in GEP is not due to the role of the O atom but due to a Coulombic effect of the positive charge located on the cation. Furthermore, it was suggested that not GEP but net electron population (NEP) should be responsible for the redox properties.

  16. Wave function of free electron in a strong laser plasma

    International Nuclear Information System (INIS)

    Zhu Shitong; Shen Wenda; Guo Qizhi

    1993-01-01

    The wave function of free electron in a strong laser plasma is obtained by solving exactly the Dirac equation in a curved space-time with optical metric for the laser plasma. When the laser field is diminished to zero, the wave function is naturally reduced to relativistic wave function of free electron. The possible application of the wave function is discussed

  17. The electronic-cigarette: effects on desire to smoke, withdrawal symptoms and cognition.

    Science.gov (United States)

    Dawkins, Lynne; Turner, John; Hasna, Surrayyah; Soar, Kirstie

    2012-08-01

    Electronic cigarettes (e-cigarettes) are battery operated devices that deliver nicotine via inhaled vapour. Few studies have evaluated acute effects on craving and mood, and none have explored effects on cognition. This study aimed to explore the effects of the White Super e-cigarette on desire to smoke, nicotine withdrawal symptoms, attention and working memory. Eighty-six smokers were randomly allocated to either: 18 mg nicotine e-cigarette (nicotine), 0mg e-cigarette (placebo), or just hold the e-cigarette (just hold) conditions. Participants rated their desire to smoke and withdrawal symptoms at baseline (T1), and five (T2) and twenty (T3) minutes after using the e-cigarette ad libitum for 5 min. A subset of participants completed the Letter Cancellation and Brown-Peterson Working Memory Tasks. After 20 min, compared with the just hold group, desire to smoke and some aspects of nicotine withdrawal were significantly reduced in the nicotine and placebo group; the nicotine e-cigarette was superior to placebo in males but not in females. The nicotine e-cigarette also improved working memory performance compared with placebo at the longer interference intervals. There was no effect of nicotine on Letter Cancellation performance. To conclude, the White Super e-cigarette alleviated desire to smoke and withdrawal symptoms 20 min after use although the nicotine content was more important for males. This study also demonstrated for the first time that the nicotine e-cigarette can enhance working memory performance. Further evaluation of the cognitive effects of the e-cigarette and its efficacy as a cessation tool is merited. Copyright © 2012 Elsevier Ltd. All rights reserved.

  18. Atomic and free electrons in a strong light field

    CERN Document Server

    Fedorov, Mikhail V

    1997-01-01

    This book presents and describes a series of unusual and striking strong-field phenomena concerning atoms and free electrons. Some of these phenomena are: multiphoton stimulated bremsstrahlung, free-electron lasers, wave-packet physics, above-threshold ionization, and strong-field stabilization in Rydberg atoms. The theoretical foundations and causes of the phenomena are described in detail, with all the approximations and derivations discussed. All the known and relevant experiments are described too, and their results are compared with those of the existing theoretical models.An extensive ge

  19. The Electron-Phonon Interaction in Strongly Correlated Systems

    International Nuclear Information System (INIS)

    Castellani, C.; Grilli, M.

    1995-01-01

    We analyze the effect of strong electron-electron repulsion on the electron-phonon interaction from a Fermi-liquid point of view and show that the electron-electron interaction is responsible for vertex corrections, which generically lead to a strong suppression of the electron-phonon coupling in the v F q/ω >>1 region, while such effect is not present when v F q/ω F is the Fermi velocity and q and ω are the transferred momentum and frequency respectively. In particular the e-ph scattering is suppressed in transport properties which are dominated by low-energy-high-momentum processes. On the other hand, analyzing the stability criterion for the compressibility, which involves the effective interactions in the dynamical limit, we show that a sizable electron-phonon interaction can push the system towards a phase-separation instability. Finally a detailed analysis of these ideas is carried out using a slave-boson approach for the infinite-U three-band Hubbard model in the presence of a coupling between the local hole density and a dispersionless optical phonon. (author)

  20. Spin effects in strong-field laser-electron interactions

    International Nuclear Information System (INIS)

    Ahrens, S; Bauke, H; Müller, T-O; Villalba-Chávez, S; Müller, C

    2013-01-01

    The electron spin degree of freedom can play a significant role in relativistic scattering processes involving intense laser fields. In this contribution we discuss the influence of the electron spin on (i) Kapitza-Dirac scattering in an x-ray laser field of high intensity, (ii) photo-induced electron-positron pair production in a strong laser wave and (iii) multiphoton electron-positron pair production on an atomic nucleus. We show that in all cases under consideration the electron spin can have a characteristic impact on the process properties and their total probabilities. To this end, spin-resolved calculations based on the Dirac equation in the presence of an intense laser field are performed. The predictions from Dirac theory are also compared with the corresponding results from the Klein-Gordon equation.

  1. Interaction between Electron Holes in a Strongly Magnetized Plasma

    DEFF Research Database (Denmark)

    Lynov, Jens-Peter; Michelsen, Poul; Pécseli, Hans

    1980-01-01

    The interaction between electron holes in a strongly magnetized, plasma-filled waveguide is investigated by means of computer simulation. Two holes may or may not coalesce, depending on their amplitudes and velocities. The interaction between holes and Trivelpiece-Gould solitons is demonstrated...

  2. Electromagnetic pulses in a strongly magnetized electron-positron plasma

    International Nuclear Information System (INIS)

    Yu, M.Y.; Rao, N.N.

    1985-01-01

    The conditions for the existence of large-amplitude localized electromagnetic wave pulses in an electron-positron plasma penetrated by a very strong ambient magnetic field are obtained. It is shown that such pulses can exist in pulsar polar magnetospheres. 12 references

  3. International Conference on Strongly Correlated Electron Systems 2017 (SCES2017)

    Science.gov (United States)

    2018-05-01

    The 2017 International Conference on Strongly Correlated Electron Systems, SCES 2017, took place at the Clarion Congress Hotel in Prague, Czech Republic from July 17 to 21, 2017. The meeting was held under the auspices of the Department of Condensed Matter Physics of the Faculty of Mathematics and Physics of the Charles University.

  4. Atomic and Free Electrons in a Strong Light Field

    International Nuclear Information System (INIS)

    Fedorov, Mikhail V.

    1998-02-01

    This book presents and describes a series of unusual and striking strong-field phenomena concerning atoms and free electrons. Some of these phenomena are: multiphoton stimulated Bremsstrahlung, free-electron lasers, ave-packet physics, above-threshold ionization, and strong-field stabilization in Rydberg atoms. The theoretical foundations and causes of the phenomena are described in detail, with all the approximations and derivations discussed. All the known and relevant experiments are described oo, and their results are compared with those of the existing theoretical models. An extensive general theoretical introduction gives a good basis for subsequent parts of the book and is an independent and self-sufficient description of the most efficient theoretical methods of the strong-field and multiphoton physics. This book can serve as a textbook for graduate students

  5. Attosecond Electron Wave Packet Dynamics in Strong Laser Fields

    International Nuclear Information System (INIS)

    Johnsson, P.; Remetter, T.; Varju, K.; L'Huillier, A.; Lopez-Martens, R.; Valentin, C.; Balcou, Ph.; Kazamias, S.; Mauritsson, J.; Gaarde, M. B.; Schafer, K. J.; Mairesse, Y.; Wabnitz, H.; Salieres, P.

    2005-01-01

    We use a train of sub-200 attosecond extreme ultraviolet (XUV) pulses with energies just above the ionization threshold in argon to create a train of temporally localized electron wave packets. We study the energy transfer from a strong infrared (IR) laser field to the ionized electrons as a function of the delay between the XUV and IR fields. When the wave packets are born at the zero crossings of the IR field, a significant amount of energy (∼20 eV) is transferred from the field to the electrons. This results in dramatically enhanced above-threshold ionization in conditions where the IR field alone does not induce any significant ionization. Because both the energy and duration of the wave packets can be varied independently of the IR laser, they are valuable tools for studying and controlling strong-field processes

  6. Energy exchange in strongly coupled plasmas with electron drift

    International Nuclear Information System (INIS)

    Akbari-Moghanjoughi, M.; Ghorbanalilu, M.

    2015-01-01

    In this paper, the generalized viscoelastic collisional quantum hydrodynamic model is employed in order to investigate the linear dielectric response of a quantum plasma in the presence of strong electron-beam plasma interactions. The generalized Chandrasekhar's relativistic degeneracy pressure together with the electron-exchange and Coulomb interaction effects are taken into account in order to extend current research to a wide range of plasma number density relevant to big planetary cores and astrophysical compact objects. The previously calculated shear viscosity and the electron-ion collision frequencies are used for strongly coupled ion fluid. The effect of the electron-beam velocity on complex linear dielectric function is found to be profound. This effect is clearly interpreted in terms of the wave-particle interactions and their energy-exchange according to the sign of the imaginary dielectric function, which is closely related to the wave attenuation coefficient in plasmas. Such kinetic effect is also shown to be in close connection with the stopping power of a charged-particle beam in a quantum plasma. The effect of many independent plasma parameters, such as the ion charge-state, electron beam-velocity, and relativistic degeneracy, is shown to be significant on the growing/damping of plasma instability or energy loss/gain of the electron-beam

  7. Electronically Strongly Coupled Divinylheterocyclic-Bridged Diruthenium Complexes.

    Science.gov (United States)

    Pfaff, Ulrike; Hildebrandt, Alexander; Korb, Marcus; Oßwald, Steffen; Linseis, Michael; Schreiter, Katja; Spange, Stefan; Winter, Rainer F; Lang, Heinrich

    2016-01-11

    Complexes [{Ru(CO)Cl(PiPr3 )2 }2 (μ-2,5-(CH-CH)2 -(c) C4 H2 E] (E=NR; R=C6 H4 -4-NMe2 (10 a), C6 H4 -4-OMe (10 b), C6 H4 -4-Me (10 c), C6 H5 (10 d), C6 H4 -4-CO2 Et (10 e), C6 H4 -4-NO2 (10 f), C6 H3 -3,5-(CF3 )2 (10 g), CH3 (11); E=O (12), S (13)) are discussed. The solid state structures of four alkynes and two complexes are reported. (Spectro)electrochemical studies show a moderate influence of the nature of the heteroatom and the electron-donating or -withdrawing substituents R in 10 a-g on the electrochemical and spectroscopic properties. The CVs display two consecutive one-electron redox events with ΔE°'=350-495 mV. A linear relationship between ΔE°' and the σp Hammett constant for 10 a-f was found. IR, UV/Vis/NIR and EPR studies for 10(+) -13(+) confirm full charge delocalization over the {Ru}CH-CH-heterocycle-CH-CH{Ru} backbone, classifying them as Class III systems according to the Robin and Day classification. DFT-optimized structures of the neutral complexes agree well with the experimental ones and provide insight into the structural consequences of stepwise oxidations. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Electron-photon and electron-electron interactions in the presence of strong electromagnetic fields

    International Nuclear Information System (INIS)

    Surzhykov, A.; Fritzsche, S.; Stoehlker, Th.

    2010-01-01

    During the last decade, photon emission from highly-charged, heavy ions has been in the focus of intense studies at the GSI accelerator and storage ring facility in Darmstadt. These studies have revealed unique information about the electron-electron and electron-photon interactions in the presence of extremely strong nuclear fields. Apart from the radiative electron capture processes, characteristic photon emission following collisional excitation of projectile ions has also attracted much interest. In this contribution, we summarize the recent theoretical studies on the production of excited ionic states and their subsequent radiative decay. We will pay special attention to the angular and polarization properties of Kα emission from helium-like ions produced by means of dielectronic recombination. The results obtained for this (resonant) capture process will be compared with the theoretical predictions for the characteristic X-rays following Coulomb excitation and radiative recombination of few-electron, heavy ions. Work is supported by Helmholtz Association and GSl under the project VH-NG--421. (author)

  9. Magnetic properties of metallic impurities with strongly correlated electrons

    Czech Academy of Sciences Publication Activity Database

    Janiš, Václav; Ringel, Matouš

    2009-01-01

    Roč. 115, č. 1 (2009), s. 30-35 ISSN 0587-4246 R&D Projects: GA ČR GA202/07/0644 Institutional research plan: CEZ:AV0Z10100520 Keywords : And erson impurity * strong electron correlations * spin-polarized solution * three-channel parquet equations * magnetic field Subject RIV: BE - Theoretical Physics Impact factor: 0.433, year: 2009 http://przyrbwn.icm.edu.pl/APP/ABSTR/115/a115-1-5.html

  10. Strong plasma turbulence in the earth's electron foreshock

    Science.gov (United States)

    Robinson, P. A.; Newman, D. L.

    1991-01-01

    A quantitative model is developed to account for the distribution in magnitude and location of the intense plasma waves observed in the earth's electron foreshock given the observed rms levels of waves. In this model, nonlinear strong-turbulence effects cause solitonlike coherent wave packets to form and decouple from incoherent background beam-excited weak turbulence, after which they convect downstream with the solar wind while collapsing to scales as short as 100 m and fields as high as 2 V/m. The existence of waves with energy densities above the strong-turbulence wave-collapse threshold is inferred from observations from IMP 6 and ISEE 1 and quantitative agreement is found between the predicted distribution of fields in an ensemble of such wave packets and the actual field distribution observed in situ by IMP 6. Predictions for the polarization of plasma waves and the bandwidth of ion-sound waves are also consistent with the observations. It is shown that strong-turbulence effects must be incorporated in any comprehensive theory of the propagation and evolution of electron beams in the foreshock. Previous arguments against the existence of strong turbulence in the foreshock are refuted.

  11. Strong plasma turbulence in the earth's electron foreshock

    International Nuclear Information System (INIS)

    Robinson, P.A.; Newman, D.L.

    1991-01-01

    A quantitative model is developed to account for the distribution in magnitude and location of the intense plasma waves observed in the Earth's electron foreshock given the observed rms levels of waves. In this model, nonlinear strong-turbulence effects cause solitonlike coherent wave packets to form and decouple from incoherent background beam-excited weak turbulence, after which they convect downstream with the solar wind while collapsing to scales as short as 100 m and fields as high as 2 V m -1 . The existence of waves with energy densities above the strong-turbulence wave-collapse threshold is inferred from observations from IMP 6 and ISEE 1 and quantitative agreement is found between the predicted distribution of fields in an ensemble of such wave packets and the actual field distribution observed in situ by IMP 6. Predictions for the polarization of plasma waves and the bandwidth of ion-sound waves are also consistent with the observations. It is shown that strong-turbulence effects must be incorporated in any comprehensive theory of the propagation and evolution of electron beams in the foreshock. Previous arguments against the existence of strong turbulence in the foreshock are refuted

  12. Spectral contents of electron waves under strong Langmuir turbulence

    Energy Technology Data Exchange (ETDEWEB)

    Alves, Maria Virginia; Dallaqua, Renato Sergio [Instituto Nacional de Pesquisas Espaciais (INPE), Sao Jose dos Campos, SP (Brazil); Prado, Fabio do [Centro Universitario UNIFEI, Itajuba, MG (Brazil); Karfidov, Dmitry Mikhailovich [General Physics Inst., Moscow (Russian Federation)

    2003-07-01

    Experimental results of electron plasma waves excited in a beam plasma system are presented. Based on our experimental results we determine the transition from the quasi-linear to non-linear regime. We present the space evolution of the electron beam distribution function for both regimes. The spectrum of the electron plasma wave in the non-linear regime shows a component with frequency larger than the plasma frequency besides the plasma frequency itself. We show that the higher frequency component is strongly affected by Landau damping, indicating a dissipation region. The measured experimental power spectrum of this wave shows a dependence on wave number k given by W{sub k} {proportional_to} k{sup -7/2} as theoretically predicted. (author)

  13. Electronic Maxwell demon in the coherent strong-coupling regime

    Science.gov (United States)

    Schaller, Gernot; Cerrillo, Javier; Engelhardt, Georg; Strasberg, Philipp

    2018-05-01

    We consider an external feedback control loop implementing the action of a Maxwell demon. Applying control actions that are conditioned on measurement outcomes, the demon may transport electrons against a bias voltage and thereby effectively converts information into electric power. While the underlying model—a feedback-controlled quantum dot that is coupled to two electronic leads—is well explored in the limit of small tunnel couplings, we can address the strong-coupling regime with a fermionic reaction-coordinate mapping. This exact mapping transforms the setup into a serial triple quantum dot coupled to two leads. We find that a continuous projective measurement of the central dot occupation would lead to a complete suppression of electronic transport due to the quantum Zeno effect. In contrast, by using a microscopic detector model we can implement a weak measurement, which allows for closure of the control loop without transport blockade. Then, in the weak-coupling regime, the energy flows associated with the feedback loop are negligible, and dominantly the information gained in the measurement induces a bound for the generated electric power. In the strong coupling limit, the protocol may require more energy for operating the control loop than electric power produced, such that the whole device is no longer information dominated and can thus not be interpreted as a Maxwell demon.

  14. A Prototypical First-Generation Electronic Cigarette Does Not Reduce Reports of Tobacco Urges or Withdrawal Symptoms among Cigarette Smokers

    Directory of Open Access Journals (Sweden)

    Arit M. Harvanko

    2017-01-01

    Full Text Available It is unknown whether first-generation electronic cigarettes reduce smoking urges and withdrawal symptoms following a 24 h deprivation period. This study tested whether a first-generation electronic cigarette reduces smoking urges and withdrawal symptoms in cigarette smokers. Following 24 h of tobacco deprivation, using a within-subjects design, eight nontreatment seeking tobacco cigarette smokers (3 females administered 10 puffs from a conventional cigarette or a first-generation electronic cigarette containing liquid with 0, 8 or 16 mg/ml nicotine. Conventional cigarettes ameliorated smoking urges and electronic cigarettes did not, regardless of nicotine concentration. First-generation electronic cigarettes may not effectively substitute for conventional cigarettes in reducing smoking urges, regardless of nicotine concentration.

  15. Bound states in strongly correlated magnetic and electronic systems

    International Nuclear Information System (INIS)

    Trebst, S.

    2002-02-01

    A novel strong coupling expansion method to calculate two-particle spectra of quantum lattice models is developed. The technique can be used to study bosonic and fermionic models and in principle it can be applied to systems in any dimension. A number of strongly correlated magnetic and electronic systems are examined including the two-leg spin-half Heisenberg ladder, the dimerized Heisenberg chain with a frustrating next-nearest neighbor interaction, coupled Heisenberg ladders, and the one-dimensional Kondo lattice model. In the various models distinct bound states are found below the two-particle continuum. Quantitative calculations of the dispersion, coherence length and binding energy of these bound states are used to describe spectroscopic experiments on (Ca,La) 14 Cu 24 O 41 and NaV 2 O 5 . (orig.)

  16. Effects of electron-withdrawing group and electron-donating core combinations on physical properties and photovoltaic performance in D-pi-A star-shaped small molecules

    NARCIS (Netherlands)

    Luponosov, Yuriy N.; Min, Jie; Solodukhin, Alexander N.; Kozlov, Oleg V.; Obrezkova, Marina A.; Peregudova, Svetlana M.; Ameri, Tayebeh; Chvalun, Sergei N.; Pshenichnikov, Maxim S.; Brabec, Christoph J.; Ponomarenko, Sergei A.

    The first representatives of star-shaped molecules having 3-alkylrhodanine (alkyl-Rh) electron-withdrawing groups, linked through bithiophene pi-spacer with electron-donating either triphenylamine (TPA) or tris(2-methoxyphenyl)amine (m-TPA) core were synthesized. The physical properties and

  17. Strongly correlated electron materials. I. Theory of the quasiparticle structure

    International Nuclear Information System (INIS)

    Lopez-Aguilar, F.; Costa-Quintana, J.; Puig-Puig, L.

    1993-01-01

    In this paper we give a method for analyzing the renormalized electronic structure of the Hubbard systems. The first step is the determination of effective interactions from the random-phase approximation (RPA) and from an extended RPA (ERPA) that introduces vertex effects within the bubble polarization. The second step is the determination of the density of states deduced from the spectral functions. Its analysis leads us to conclude that these systems can exhibit three types of resonances in their electronic structures: the lower-, middle-, and upper-energy resonances. Furthermore, we analyze the conditions for which there is only one type of resonance and the causes that lead to the disappearance of the heavy-fermion state. We finally introduce the RPA and ERPA effective interactions within the strong-coupling theory and we give the conditions for obtaining coupling and superconductivity

  18. Oscillating molecular dipoles require strongly correlated electronic and nuclear motion

    International Nuclear Information System (INIS)

    Chang, Bo Y; Shin, Seokmin; Palacios, Alicia; Martín, Fernando; Sola, Ignacio R

    2015-01-01

    To create an oscillating electric dipole in an homonuclear diatomic cation without an oscillating driver one needs (i) to break the symmetry of the system and (ii) to sustain highly correlated electronic and nuclear motion. Based on numerical simulations in H 2 + we present results for two schemes. In the first one (i) is achieved by creating a superposition of symmetric and antisymmetric electronic states freely evolving, while (ii) fails. In a second scheme, by preparing the system in a dressed state of a strong static field, both conditions hold. We then analyze the robustness of this scheme with respect to features of the nuclear wave function and its intrinsic sources of decoherence. (tutorial)

  19. Crossover in tunneling hops in systems of strongly localized electrons

    International Nuclear Information System (INIS)

    Lien Nguyen, V.; Gamietea, A.D.

    1995-11-01

    Accurate Monte-Carlo simulation data show a consistent crossover in different characters of tunneling hops in two-dimensional systems of strongly localized electrons in the presence of scattering and quantum interference of hopping paths. The results also suggest a negative answer to the question whether there is a two-dimensional sign phase transition. The fractal behaviour observed in the direction perpendicular to the hopping direction is found to be similar to that for eigenstates in one-dimensional localized systems. (author). 16 refs, 6 figs

  20. Fast electronic structure methods for strongly correlated molecular systems

    International Nuclear Information System (INIS)

    Head-Gordon, Martin; Beran, Gregory J O; Sodt, Alex; Jung, Yousung

    2005-01-01

    A short review is given of newly developed fast electronic structure methods that are designed to treat molecular systems with strong electron correlations, such as diradicaloid molecules, for which standard electronic structure methods such as density functional theory are inadequate. These new local correlation methods are based on coupled cluster theory within a perfect pairing active space, containing either a linear or quadratic number of pair correlation amplitudes, to yield the perfect pairing (PP) and imperfect pairing (IP) models. This reduces the scaling of the coupled cluster iterations to no worse than cubic, relative to the sixth power dependence of the usual (untruncated) coupled cluster doubles model. A second order perturbation correction, PP(2), to treat the neglected (weaker) correlations is formulated for the PP model. To ensure minimal prefactors, in addition to favorable size-scaling, highly efficient implementations of PP, IP and PP(2) have been completed, using auxiliary basis expansions. This yields speedups of almost an order of magnitude over the best alternatives using 4-center 2-electron integrals. A short discussion of the scope of accessible chemical applications is given

  1. Localized Electron Heating by Strong Guide-Field Magnetic Reconnection

    Science.gov (United States)

    Guo, Xuehan; Sugawara, Takumichi; Inomoto, Michiaki; Yamasaki, Kotaro; Ono, Yasushi; UTST Team

    2015-11-01

    Localized electron heating of magnetic reconnection was studied under strong guide-field (typically Bt 15Bp) using two merging spherical tokamak plasmas in Univ. Tokyo Spherical Tokamak (UTST) experiment. Our new slide-type two-dimensional Thomson scattering system documented for the first time the electron heating localized around the X-point. The region of high electron temperature, which is perpendicular to the magnetic field, was found to have a round shape with radius of 2 [cm]. Also, it was localized around the X-point and does not agree with that of energy dissipation term Et .jt . When we include a guide-field effect term Bt / (Bp + αBt) for Et .jt where α =√{ (vin2 +vout2) /v∥2 } , the energy dissipation area becomes localized around the X-point, suggesting that the electrons are accelerated by the reconnection electric field parallel to the magnetic field and thermalized around the X-point. This work was supported by JSPS A3 Foresight Program ``Innovative Tokamak Plasma Startup and Current Drive in Spherical Torus,'' a Grant-in-Aid from the Japan Society for the Promotion of Science (JSPS) Fellows 15J03758.

  2. Strongly Coupled Magnetic and Electronic Transitions in Multivalent Strontium Cobaltites.

    Science.gov (United States)

    Lee, J H; Choi, Woo Seok; Jeen, H; Lee, H-J; Seo, J H; Nam, J; Yeom, M S; Lee, H N

    2017-11-22

    The topotactic phase transition in SrCoO x (x = 2.5-3.0) makes it possible to reversibly transit between the two distinct phases, i.e. the brownmillerite SrCoO 2.5 that is a room-temperature antiferromagnetic insulator (AFM-I) and the perovskite SrCoO 3 that is a ferromagnetic metal (FM-M), owing to their multiple valence states. For the intermediate x values, the two distinct phases are expected to strongly compete with each other. With oxidation of SrCoO 2.5 , however, it has been conjectured that the magnetic transition is decoupled to the electronic phase transition, i.e., the AFM-to-FM transition occurs before the insulator-to-metal transition (IMT), which is still controversial. Here, we bridge the gap between the two-phase transitions by density-functional theory calculations combined with optical spectroscopy. We confirm that the IMT actually occurs concomitantly with the FM transition near the oxygen content x = 2.75. Strong charge-spin coupling drives the concurrent IMT and AFM-to-FM transition, which fosters the near room-T magnetic transition characteristic. Ultimately, our study demonstrates that SrCoO x is an intriguingly rare candidate for inducing coupled magnetic and electronic transition via fast and reversible redox reactions.

  3. RAMAN LIGHT SCATTERING IN PSEUDOSPIN-ELECTRON MODEL AT STRONG PSEUDOSPIN-ELECTRON INTERACTION

    Directory of Open Access Journals (Sweden)

    T.S.Mysakovych

    2004-01-01

    Full Text Available Anharmonic phonon contributions to Raman scattering in locally anharmonic crystal systems in the framework of the pseudospin-electron model with tunneling splitting of levels are investigated. The case of strong pseudospin-electron coupling is considered. Pseudospin and electron contributions to scattering are taken into account. Frequency dependences of Raman scattering intensity for different values of model parameters and for different polarization of scattering and incident light are investigated.

  4. The comparative efficacy of first- versus second-generation electronic cigarettes in reducing symptoms of nicotine withdrawal.

    Science.gov (United States)

    Lechner, William V; Meier, Ellen; Wiener, Josh L; Grant, DeMond M; Gilmore, Jenna; Judah, Matt R; Mills, Adam C; Wagener, Theodore L

    2015-05-01

    Currently, electronic cigarettes (e-cigarettes) are studied as though they are a homogeneous category. However, there are several noteworthy differences in the products that fall under this name, including potential differences in the efficacy of these products as smoking cessation aids. The current study examined the comparative efficacy of first- and second-generation e-cigarettes in reducing nicotine withdrawal symptoms in a sample of current smokers with little or no experience of using e-cigarettes. Twenty-two mildly to moderately nicotine-dependent individuals were randomized to a cross-over design in which they used first- and second-generation e-cigarettes on separate days with assessment of withdrawal symptoms directly prior to and after product use. A community-based sample recruited in the Midwest region of the United States reported a mean age of 28.6 [standard deviation (SD) = 12.9]. The majority were male (56.5%), Caucasian (91.3%), reported smoking an average of 15.2 (SD = 9.6) tobacco cigarettes per day, and a mean baseline carbon monoxide (CO) level of 18.7 parts per million (p.p.m.). Symptoms of withdrawal from nicotine were measured via the Mood and Physical Symptoms Scale. Analysis of changes in withdrawal symptoms revealed a significant time × product interaction F(1, 21)  = 5.057, P = 0.036, n(2) P  = 0.202. Participants experienced a larger reduction in symptoms of nicotine withdrawal after using second-generation compared with first-generation e-cigarettes. Second-generation e-cigarettes seem to be more effective in reducing symptoms of nicotine withdrawal than do first-generation e-cigarettes. © 2015 Society for the Study of Addiction.

  5. PREFACE: International Conference on Strongly Correlated Electron Systems (SCES 2011)

    Science.gov (United States)

    Littlewood, P. B.; Lonzarich, G. G.; Saxena, S. S.; Sutherland, M. L.; Sebastian, S. E.; Artacho, E.; Grosche, F. M.; Hadzibabic, Z.

    2012-11-01

    The Strongly Correlated Electron Systems Conference (SCES) 2011, was held from 29 August-3 September 2011, in Cambridge, UK. SCES'2011 was dedicated to 100 years of superconductivity and covered a range of topics in the area of strongly correlated systems. The correlated electronic and magnetic materials featured include f-electron based heavy fermion intermetallics and d-electron based transition metal compounds. The meeting welcomed to Cambridge 657 participants from 23 countries, who presented 127 talks (including 16 plenary, 57 invited, and 54 contributed) and 736 posters in 40 sessions over five full days of meetings. This proceedings volume contains papers reporting on the science presented at the meeting. This work deepens our understanding of the rich physical phenomena that arise from correlation effects. Strongly correlated systems are known for their remarkable array of emergent phenomena: the traditional subjects of superconductivity, magnetism and metal-insulator transitions have been joined by non-Fermi liquid phenomena, topologically protected quantum states, atomic and photonic gases, and quantum phase transitions. These are some of the most challenging and interesting phenomena in science. As well as the science driver, there is underlying interest in energy-dense materials, which make use of 'small' electrons packed to the highest possible density. These are by definition 'strongly correlated'. For example: good photovoltaics must be efficient optical absorbers, which means that photons will generate tightly bound electron-hole pairs (excitons) that must then be ionised at a heterointerface and transported to contacts; efficient solid state refrigeration depends on substantial entropy changes in a unit cell, with large local electrical or magnetic moments; efficient lighting is in a real sense the inverse of photovoltaics; the limit of an efficient battery is a supercapacitor employing mixed valent ions; fuel cells and solar to fuel conversion

  6. Non perturbative aspects of strongly correlated electron systems

    International Nuclear Information System (INIS)

    Controzzi, D.

    2000-01-01

    In this thesis we report some selected works on Strongly Correlated Electron Systems. A common ingredient of these works is the use of non-perturbative techniques available in low dimensions. In the first part we use the Bethe Ansatz to study some properties of two families of integrable models introduced by Fateev. We calculate the Thermodynamics of the models and show how they can be interpreted as effective Landau-Ginzburg theories for coupled two-dimensional superconductors interacting with an insulating substrate. This allows us to study exactly the dependence of the critical temperature on the thickness of the insulating layer, and on the interaction between the order parameters of two different superconducting planes. In the second part of the thesis we study the optical conductivity of the sine-Gordon model using the Form Factor method and Conformal Perturbation Theory. This allows us to develop, for the first time, a complete theory of the optical conductivity of one-dimensional Mott insulators, in the Quantum Field Theory limit. (author)

  7. Mechanisms of molecular electronic rectification through electronic levels with strong vibrational coupling

    DEFF Research Database (Denmark)

    Kuznetsov, A.M.; Ulstrup, Jens

    2002-01-01

    We present a new view and an analytical formalism of electron flow through a donor-acceptor molecule inserted between a pair of metal electrodes. The donor and acceptor levels are strongly coupled to an environmental nuclear continuum. The formalism applies to molecular donor-acceptor systems bot...

  8. Superconductivity in strongly correlated electron systems: successes and open questions

    International Nuclear Information System (INIS)

    Shastry, B. Sriram

    2000-01-01

    Correlated electronic systems and superconductivity is a field which has unique track record of producing exciting new phases of matter. The article gives an overview of trends in solving the problems of superconductivity and correlated electronic systems

  9. Radiation effects on relativistic electrons in strong external fields

    International Nuclear Information System (INIS)

    Iqbal, Khalid

    2013-01-01

    The effects of radiation of high energy electron beams are a major issue in almost all types of charged particle accelerators. The objective of this thesis is both the analytical and numerical study of radiation effects. Due to its many applications the study of the self force has become a very active and productive field of research. The main part of this thesis is devoted to the study of radiation effects in laser-based plasma accelerators. Analytical models predict the existence of radiation effects. The investigation of radiation reaction show that in laser-based plasma accelerators, the self force effects lower the energy gain and emittance for moderate energies electron beams and increase the relative energy spread. However, for relatively high energy electron beams, the self radiation and retardation (radiation effects of one electron on the other electron of the system) effects increase the transverse emittance of the beam. The energy gain decreases to even lower value and relative energy spread increases to even higher value due to high radiation losses. The second part of this thesis investigates with radiation reaction in focused laser beams. Radiation effects are very weak even for high energy electrons. The radiation-free acceleration and the simple practical setup make direct acceleration in a focused laser beam very attractive. The results presented in this thesis can be helpful for the optimization of future electron acceleration experiments, in particular in the case of laser-plasma accelerators.

  10. Excitonic condensation in systems of strongly correlated electrons

    Czech Academy of Sciences Publication Activity Database

    Kuneš, Jan

    2015-01-01

    Roč. 27, č. 33 (2015), s. 333201 ISSN 0953-8984 Institutional support: RVO:68378271 Keywords : electronic correlations * exciton * Bose-Einstein condensation Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.209, year: 2015

  11. Observation of the two-electron cusp in atomic collisions. Evidence for strong electron-electron correlation

    International Nuclear Information System (INIS)

    Sarkadi, L.; Orban, A.

    2007-01-01

    Complete text of publication follows. In this report we present experimental data for a process when two electrons with velocity vectors equal to that of the projectile are emitted from collisions. By observing the two electron cusp the study of the threshold phenomenon for two-electron break-up is possible. It is a particularly interesting question whether the outgoing charged projectile can attract the two repulsing electrons so strongly that the two-electron cusp is formed. If it is so, a further question arises: Are the two electrons correlated in the final state as it is predicted by the Wannier theory? The experiments have been done at the 1 MeV VdG accelerator of ATOMKI using our TOF spectrometer. The first measurements clearly showed the formation of the two-electron cusp and signature of the electron correlation in 200 keV He 0 +He collisions. These promising results motivated us to carry out the experiment at 100 keV beam energy where the coincidence count rate is still reasonable but the energy resolution is better. For an acceptable data acquisition time we improved our data acquisition and data processing system for triple coincidence measurements. In Fig. 1a we present our measured relative fourfold differential cross section (FDCS) that shows strong electron correlation. For a comparison, in Fig. 1b we displayed the contour plot for uncorrelated electron pair emission. These latter data were synthesized artificially, generating the energies of the electron pairs from two independent double coincidence experiments. In both figures the distributions are characterized by two ridges. In Fig. 1b the ridges are perpendicular straight lines (E 1 = E 2 .13.6 eV). As a result of the correlation, the ridges in Fig. 1a are distorted in such a way that they have a joint straight-line section following the line E 1 + E 2 = 27.2 eV. This means that the electron pairs in the vicinity of the cusp maximum are emitted with a center of- mass velocity equal to that of

  12. Effect of strong coupling on interfacial electron transfer dynamics in ...

    Indian Academy of Sciences (India)

    Unknown

    regarded as the best sensitizing dyes for solar energy conversion for their strong visible absorption bands, long-lived ... solar cells based on dye-sensitized nanocrystalline. TiO2. High affinity for the TiO2 surface, which is ... pump pulses at 400 nm, one part of 800 nm with. 200 µJ/pulse, is frequency doubled in BBO crystals.

  13. Electron dynamics in metals and semiconductors in strong THz fields

    DEFF Research Database (Denmark)

    Jepsen, Peter Uhd

    2017-01-01

    Semiconductors and metals respond to strong electric fields in a highly nonlinear fashion. Using single-cycle THz field transients it is possible to investigate this response in regimes not accessible by transport-based measurements. Extremely high fields can be applied without material damage...

  14. Thallium trinitrate-mediated ring contraction of 1,2-dihydronaphthalenes: the effect of electron-donating and electron-withdrawing groups

    International Nuclear Information System (INIS)

    Silva Junior, Luiz F.; Sousa, Raquel M.F.; Ferraz, Helena M.C.; Aguilar, Andrea M.

    2005-01-01

    The oxidation of a series of 1,2-dihydronaphthalenes substituted in the aromatic ring was investigated with thallium trinitrate (TTN) in methanol or in trimethylorthoformate (TMOF) as solvent. In all cases, indans are produced, although the yield varied from excellent to poor, depending on the structure of the substrate. The presence of an electron-donating group in the substrate favors the rearrangement, whereas significant amounts of glycolic derivatives, as well as naphthalenes, were obtained in the oxidation of 1,2-dihydronaphthalenes bearing electron-withdrawing groups, such as Br and NO 2 . Mechanisms for the formation of each of these products are proposed. (author)

  15. Strongly driven electron spins using a Ku band stripline electron paramagnetic resonance resonator

    Science.gov (United States)

    Yap, Yung Szen; Yamamoto, Hiroshi; Tabuchi, Yutaka; Negoro, Makoto; Kagawa, Akinori; Kitagawa, Masahiro

    2013-07-01

    This article details our work to obtain strong excitation for electron paramagnetic resonance (EPR) experiments by improving the resonator's efficiency. The advantages and application of strong excitation are discussed. Two 17 GHz transmission-type, stripline resonators were designed, simulated and fabricated. Scattering parameter measurements were carried out and quality factor were measured to be around 160 and 85. Simulation results of the microwave's magnetic field distribution are also presented. To determine the excitation field at the sample, nutation experiments were carried out and power dependence were measured using two organic samples at room temperature. The highest recorded Rabi frequency was rated at 210 MHz with an input power of about 1 W, which corresponds to a π/2 pulse of about 1.2 ns.

  16. Strong Electron Self-Cooling in the Cold-Electron Bolometers Designed for CMB Measurements

    Science.gov (United States)

    Kuzmin, L. S.; Pankratov, A. L.; Gordeeva, A. V.; Zbrozhek, V. O.; Revin, L. S.; Shamporov, V. A.; Masi, S.; de Bernardis, P.

    2018-03-01

    We have realized cold-electron bolometers (CEB) with direct electron self-cooling of the nanoabsorber by SIN (Superconductor-Insulator-Normal metal) tunnel junctions. This electron self-cooling acts as a strong negative electrothermal feedback, improving noise and dynamic properties. Due to this cooling the photon-noise-limited operation of CEBs was realized in array of bolometers developed for the 345 GHz channel of the OLIMPO Balloon Telescope in the power range from 10 pW to 20 pW at phonon temperature Tph =310 mK. The negative electrothermal feedback in CEB is analogous to TES but instead of artificial heating we use cooling of the absorber. The high efficiency of the electron self-cooling to Te =100 mK without power load and to Te=160 mK under power load is achieved by: - a very small volume of the nanoabsorber (0.02 μm3) and a large area of the SIN tunnel junctions, - effective removal of hot quasiparticles by arranging double stock at both sides of the junctions and close position of the normal metal traps, - self-protection of the 2D array of CEBs against interferences by dividing them between N series CEBs (for voltage interferences) and M parallel CEBs (for current interferences), - suppression of Andreev reflection by a thin layer of Fe in the AlFe absorber. As a result even under high power load the CEBs are working at electron temperature Te less than Tph . To our knowledge, there is no analogue in the bolometers technology in the world for bolometers working at electron temperature colder than phonon temperature.

  17. Strongly Coupled Magnetic and Electronic Transitions in Multivalent Strontium Cobaltites

    OpenAIRE

    Lee, J. H.; Choi, Woo Seok; Jeen, H.; Lee, H.-J.; Seo, J. H.; Nam, J.; Yeom, M. S.; Lee, H. N.

    2017-01-01

    The topotactic phase transition in SrCoO x (x = 2.5–3.0) makes it possible to reversibly transit between the two distinct phases, i.e. the brownmillerite SrCoO2.5 that is a room-temperature antiferromagnetic insulator (AFM-I) and the perovskite SrCoO3 that is a ferromagnetic metal (FM-M), owing to their multiple valence states. For the intermediate x values, the two distinct phases are expected to strongly compete with each other. With oxidation of SrCoO2.5, however, it has been conjectured t...

  18. Transverse transport in coupled strongly correlated electronic chains

    International Nuclear Information System (INIS)

    Capponi, S.; Poilblanc, D.

    1997-01-01

    One-particle interchain hopping in a system of coupled Luttinger liquids is investigated by use of exact diagonalizations techniques. We give numerical evidence that inter-chain coherent hopping (defined by a non-vanishing splitting) can be totally suppressed for the Luttinger liquid exponent α ∝ 0.4 or even smaller α values. The transverse conductivity is shown to exhibit a strong incoherent part even when coherent inter-chain hopping is believed to occur. Implications for the optical experiments in quasi-1D organic or high-T c superconductors is outlined. (orig.)

  19. Quantum phase transitions of strongly correlated electron systems

    International Nuclear Information System (INIS)

    Imada, Masatoshi

    1998-01-01

    Interacting electrons in solids undergo various quantum phase transitions driven by quantum fluctuations. The quantum transitions take place at zero temperature by changing a parameter to control quantum fluctuations rather than thermal fluctuations. In contrast to classical phase transitions driven by thermal fluctuations, the quantum transitions have many different features where quantum dynamics introduces a source of intrinsic fluctuations tightly connected with spatial correlations and they have been a subject of recent intensive studies as we see below. Interacting electron systems cannot be fully understood without deep analyses of the quantum phase transitions themselves, because they are widely seen and play essential roles in many phenomena. Typical and important examples of the quantum phase transitions include metal-insulator transitions, (2, 3, 4, 5, 6, 7, 8, 9) metal-superconductor transitions, superconductor-insulator transitions, magnetic transitions to antiferromagnetic or ferromagnetic phases in metals as well as in Mott insulators, and charge ordering transitions. Here, we focus on three different types of transitions

  20. Strongly nonlinear electronic transport in Cr-Si composite films

    International Nuclear Information System (INIS)

    Burkov, A.T.; Vinzelberg, H.; Schumann, J.; Nakama, T.; Yagasaki, K.

    2004-01-01

    The phase formation, the resistivity and the thermopower of amorphous Cr 0.15 Si 0.85 , and nanocrystalline CrSi 2 -Si thin film composites have been studied. The films were produced by a magnetron sputtering of a composite target onto unheated substrates with subsequent crystallization of the film at high temperatures. As the film composite develops under the heat treatment from the initial amorphous state into the final polycrystalline material, two percolation thresholds were found. At first, the percolating cluster of nanocrystalline CrSi 2 is formed. However, this cluster is destroyed with further annealing due to crystallization and redistribution of Si. The composite films which are close to this insulating threshold reveal a strongly nonlinear conductivity. The conductivity increases with the current by two orders of magnitude

  1. Inelastic electron scattering influence on the strong coupling oxide superconductors

    International Nuclear Information System (INIS)

    Gabovich, A.M.; Voitenko, A.I.

    1995-01-01

    The superconducting order parameters Δ and energy gap Δ g are calculated taking into account the pair-breaking inelastic quasiparticle scattering by thermal Bose-excitations, e.g., phonons. The treatment is self-consistent because the scattering amplitude depends on Δ. The superconducting transition for any strength of the inelastic scattering is the phase transition of the first kind and the dependences Δ (T) and Δ g (T) tend to rectangular curve that agrees well with the experiment for high-Tc oxides. On the basis of the developed theory the nuclear spin-lattice relaxation rate R s in the superconducting state is calculated. The Hebel-Slichter peak in R s (T) is shown to disappear for strong enough inelastic scattering

  2. Density functional application to strongly correlated electron systems

    International Nuclear Information System (INIS)

    Eschrig, H.; Koepernik, K.; Chaplygin, I.

    2003-01-01

    The local spin density approximation plus onsite Coulomb repulsion approach (LSDA+U) to density functional theory is carefully reanalyzed. Its possible link to single-particle Green's function theory is occasionally discussed. A simple and elegant derivation of the important sum rules for the on-site interaction matrix elements linking them to the values of U and J is presented. All necessary expressions for an implementation of LSDA+U into a non-orthogonal basis solver for the Kohn-Sham equations are given, and implementation into the full-potential local-orbital solver (Phys. Rev. B 59 (1999) 1743) is made. Results of application to several planar cuprate structures are reported in detail and conclusions on the interpretation of the physics of the electronic structure of the cuprates are drawn

  3. Signals of strong electronic correlation in ion scattering processes

    Science.gov (United States)

    Bonetto, F.; Gonzalez, C.; Goldberg, E. C.

    2016-05-01

    Previous measurements of neutral atom fractions for S r+ scattered by gold polycrystalline surfaces show a singular dependence with the target temperature. There is still not a theoretical model that can properly describe the magnitude and the temperature dependence of the neutralization probabilities found. Here, we applied a first-principles quantum-mechanical theoretical formalism to describe the time-dependent scattering process. Three different electronic correlation approaches consistent with the system analyzed are used: (i) the spinless approach, where two charge channels are considered (S r0 and S r+ ) and the spin degeneration is neglected; (ii) the infinite-U approach, with the same charge channels (S r0 and S r+ ) but considering the spin degeneration; and (iii) the finite-U approach, where the first ionization and second ionization energy levels are considered very, but finitely, separated. Neutral fraction magnitudes and temperature dependence are better described by the finite-U approach, indicating that e -correlation plays a significant role in charge-transfer processes. However, none of them is able to explain the nonmonotonous temperature dependence experimentally obtained. Here, we suggest that small changes in the surface work function introduced by the target heating, and possibly not detected by experimental standard methods, could be responsible for that singular behavior. Additionally, we apply the same theoretical model using the infinite-U approximation for the Mg-Au system, obtaining an excellent description of the experimental neutral fractions measured.

  4. Dynamics of total electron content distribution during strong geomagnetic storms

    Science.gov (United States)

    Astafyeva, E. I.; Afraimovich, E. L.; Kosogorov, E. A.

    We worked out a new method of mapping of total electron content TEC equal lines displacement velocity The method is based on the technique of global absolute vertical TEC value mapping Global Ionospheric Maps technique GIM GIM with 2-hours time resolution are available from Internet underline ftp cddisa gsfc nasa gov in standard IONEX-files format We determine the displacement velocity absolute value as well as its wave vector orientation from increments of TEC x y derivatives and TEC time derivative for each standard GIM cell 5 in longitude to 2 5 in latitude Thus we observe global traveling of TEC equal lines but we also can estimate the velocity of these line traveling Using the new method we observed anomalous rapid accumulation of the ionosphere plasma at some confined area due to the depletion of the ionization at the other spacious territories During the main phase of the geomagnetic storm on 29-30 October 2003 very large TEC enhancements appeared in the southwest of North America TEC value in that area reached up to 200 TECU 1 TECU 10 16 m -2 It was found that maximal velocity of TEC equal lines motion exceeded 1500 m s and the mean value of the velocity was about 400 m s Azimuth of wave vectors of TEC equal lines were orientated toward the center of region with anomaly high values of TEC the southwest of North America It should be noted that maximal TEC values during geomagnetically quiet conditions is about 60-80 TECU the value of TEC equal lines

  5. Multiphonon contribution to the polaron formation in cuprates with strong electron correlations and strong electron-phonon interaction

    Science.gov (United States)

    Ovchinnikov, Sergey G.; Makarov, Ilya A.; Kozlov, Peter A.

    2017-03-01

    In this work dependences of the electron band structure and spectral function in the HTSC cuprates on magnitude of electron-phonon interaction (EPI) and temperature are investigated. We use three-band p-d model with diagonal and offdiagonal EPI with breathing and buckling phonon mode in the frameworks of polaronic version of the generalized tight binding (GTB) method. The polaronic quasiparticle excitation in the system with EPI within this approach is formed by a hybridization of the local multiphonon Franck-Condon excitations with lower and upper Hubbard bands. Increasing EPI leads to transfer of spectral weight to high-energy multiphonon excitations and broadening of the spectral function. Temperature effects are taken into account by occupation numbers of local excited polaronic states and variations in the magnitude of spin-spin correlation functions. Increasing the temperature results in band structure reconstruction, spectral weight redistribution, broadening of the spectral function peak at the top of the valence band and the decreasing of the peak intensity. The effect of EPI with two phonon modes on the polaron spectral function is discussed.

  6. IMIDAZOLE-BASED IONIC LIQUIDS FOR USE IN POLYMER ELECTROLYTE MEMBRANE FUEL CELLS: EFFECT OF ELECTRON-WITHDRAWING AND ELECTRON-DONATING SUBSTITUENTS

    Energy Technology Data Exchange (ETDEWEB)

    Chang, E.; Fu, Y.; Kerr, J.

    2009-01-01

    Current polymer electrolyte membrane fuel cells (PEMFCs) require humidifi cation for acceptable proton conductivity. Development of a novel polymer that is conductive without a water-based proton carrier is desirable for use in automobiles. Imidazole (Im) is a possible replacement for water as a proton solvent; Im can be tethered to the polymer structure by means of covalent bonds, thereby providing a solid state proton conducting membrane where the solvating groups do not leach out of the fuel cell. These covalent bonds can alter the electron availability of the Im molecule. This study investigates the effects of electron-withdrawing and electron-donating substituents on the conductivity of Im complexed with methanesulfonic acid (MSA) in the form of ionic liquids. Due to the changes in the electronegativity of nitrogen, it is expected that 2-phenylimidazole (2-PhIm, electron-withdrawing) will exhibit increased conductivity compared to Im, while 2-methylimidazole (2-MeIm, electron-donating) will exhibit decreased conductivity. Three sets of ionic liquids were prepared at defi ned molar ratios: Im-MSA, 2-PhIm-MSA, and 2-MeIm- MSA. Differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and 1H-NMR were used to characterize each complex. Impedance analysis was used to determine the conductivity of each complex. Both the 2-PhIm-MSA and 2-MeIm-MSA ionic liquids were found to be less conductive than the Im-MSA complex at base-rich compositions, but more conductive at acid-rich compositions. 1H-NMR data shows a downfi eld shift of the proton on nitrogen in 2-PhIm compared to Im, suggesting that other factors may diminish the electronic effects of the electron withdrawing group at base-rich compositions. Further studies examining these effects may well result in increased conductivity for Im-based complexes. Understanding the conductive properties of Im-derivatives due to electronic effects will help facilitate the development of a new electrolyte

  7. Theoretical study of X⁻ · 1 · YF (1 = triazine, X = Cl, Br and I, Y = H, Cl, Br, I, PH₂ and AsH₂): noncovalently electron-withdrawing effects on anion-arene interactions.

    Science.gov (United States)

    Chen, Yishan; Yao, Lifeng

    2014-01-01

    The ternary complexes X(-) · 1 · YF (1 = triazine, X = Cl, Br and I, Y = H, Cl, Br, I, PH2 and AsH2) have been investigated by MP2 calculations to understand the noncovalently electron-withdrawing effects on anion-arene interactions. The results indicate that in binary complexes (1 · X(-)), both weak σ-type and anion-π complexes can be formed for Cl(-) and Br(-), but only anion-π complex can be formed for I(-). Moreover, the hydrogen-bonding complex is the global minimum for all three halides in binary complexes. However, in ternary complexes, anion-π complex become unstable and only σ complex can retain in many cases for Cl(-) and Br(-). Anion-π complex keeps stable only when YF = HF. In contrast with binary complexes, σ complex become the global minimum for Cl(-) and Br(-) in ternary complexes. These changes in binding mode and strength are consistent with the results of covalently electron-withdrawing effects. However, in contrast with the covalently electron-withdrawing substituents, Cl(-) and Br(-) can attack the aromatic carbon atom to form a strong σ complex when the noncovalently electron-withdrawing effect is induced by halogen bonding. The binding behavior for I(-) is different from that for Cl(-) and Br(-) in two aspects. First, the anion-π complex for I(-) can also keep stable when the noncovalent interaction is halogen bonding. Second, the anion-π complex for I(-) is the global minimum when it can retain as a stable structure.

  8. The Diels-Alder Cycloaddition Reaction of Substituted Hemifullerenes with 1,3-Butadiene: Effect of Electron-Donating and Electron-Withdrawing Substituents.

    Science.gov (United States)

    Mojica, Martha; Méndez, Francisco; Alonso, Julio A

    2016-02-12

    The Diels-Alder (DA) reaction provides an attractive route to increase the number of six member rings in substituted Polycyclic Aromatic Hydrocarbons (PAHs). The density functional theory (DFT) B3LYP method has been used in this work to inquire if the substitution of H over the edge of triindenetriphenylene (pristine hemifullerene 1) and pentacyclopentacorannulene (pristine hemifullerene 2), could improve the DA cycloaddition reaction with 1,3-butadiene. The substituents tested include electron-donating (NH₂, OMe, OH, Me, i-Pr) and electron-withdrawing groups (F, COOH, CF₃, CHO, CN, NO₂). The electronic, kinetic and thermodynamic parameters of the DA reactions of the substituted hemifullerenes with 1,3-butadiene have been analyzed. The most promising results were obtained for the NO₂ substituent; the activation energy barriers for reactions using this substituent were lower than the barriers for the pristine hemifullerenes. This leads us to expect that the cycloadditions to a starting fullerene fragment will be possible.

  9. Two strongly correlated electron systems: the Kondo mode in the strong coupling limit and a 2-D model of electrons close to an electronic topological transition

    International Nuclear Information System (INIS)

    Bouis, F.

    1999-01-01

    Two strongly correlated electron systems are considered in this work, Kondo insulators and high Tc cuprates. Experiments and theory suggest on one hand that the Kondo screening occurs on a rather short length scale and on the other hand that the Kondo coupling is renormalized to infinity in the low energy limit. The strong coupling limit is then the logical approach although the real coupling is moderate. A systematic development is performed around this limit in the first part. The band structure of these materials is reproduced within this scheme. Magnetic fluctuations are also studied. The antiferromagnetic transition is examined in the case where fermionic excitations are shifted to high energy. In the second part, the Popov and Fedotov representation of spins is used to formulate the Kondo and the antiferromagnetic Heisenberg model in terms of a non-polynomial action of boson fields. In the third part the properties of high Tc cuprates are explained by a change of topology of the Fermi surface. This phenomenon would happen near the point of optimal doping and zero temperature. It results in the appearance of a density wave phase in the under-doped regime. The possibility that this phase has a non-conventional symmetry is considered. The phase diagram that described the interaction and coexistence of density wave and superconductivity is established in the mean-field approximation. The similarities with the experimental observations are numerous in particular those concerning the pseudo-gap and the behavior of the resistivity near optimal doping. (author)

  10. Electron screening and kinetic-energy oscillations in a strongly coupled plasma

    International Nuclear Information System (INIS)

    Chen, Y.C.; Simien, C.E.; Laha, S.; Gupta, P.; Martinez, Y.N.; Mickelson, P.G.; Nagel, S.B.; Killian, T.C.

    2004-01-01

    We study equilibration of strongly coupled ions in an ultracold neutral plasma produced by photoionizing laser-cooled and trapped atoms. By varying the electron temperature, we show that electron screening modifies the equilibrium ion temperature. Even with few electrons in a Debye sphere, the screening is well described by a model using a Yukawa ion-ion potential. We also observe damped oscillations of the ion kinetic energy that are a unique feature of equilibration of a strongly coupled plasma

  11. Successful withdrawal from high-dose benzodiazepine in a young patient through electronic monitoring of polypharmacy: a case report in an ambulatory setting.

    Science.gov (United States)

    Loscertales, Hèctor R; Wentzky, Valerie; Dürsteler, Kenneth; Strasser, Johannes; Hersberger, Kurt E; Arnet, Isabelle

    2017-05-01

    Dependence on high-dose benzodiazepines (BZDs) is well known and discontinuation attempts are generally unsuccessful. A well established protocol for high-dose BZD withdrawal management is lacking. We present the case of withdrawal from high-dose lorazepam (>20 mg daily) in an unemployed 35-year-old male outpatient through agonist substitution with long-acting clonazepam and electronic monitoring over 28 weeks. All medicines were repacked into weekly 7 × 4 cavity multidose punch cards with an electronic monitoring system. The prescribed daily dosages of BZDs were translated into an optimal number of daily tablets, divided into up to four units of use. Withdrawal was achieved by individual leftover of a small quantity of BZDs that was placed in a separate compartment. Feedback with visualization of intake over the past week was given during weekly psychosocial sessions. Stepwise reduction was obtained by reducing the mg content of the cavities proportionally to the leftovers, keeping the number of cavities in order to maintain regular intake behavior, and to determine the dosage decrease. At week 28, the primary objectives were achieved, that is, lorazepam reduction to 5 mg daily and cannabis abstinence. Therapy was continued using multidrug punch cards without electronic monitoring to maintain the management system. At week 48, a smaller size weekly pill organizer with detachable daily containers was dispensed. At week 68, the patient's therapy was constant with 1.5 mg clonazepam + 5 mg lorazepam daily for anxiety symptoms and the last steps of withdrawal were started. Several key factors led to successful withdrawal from high-dose BZD in this outpatient, such as the use of weekly punch cards coupled with electronic monitoring, the patient's empowerment over the withdrawal process, and the collaboration of several healthcare professionals. The major implication for clinical care is reduction by following the leftovers, and not a diktat from the healthcare

  12. Density-dependent electron scattering in photoexcited GaAs in strongly diffusive regime

    DEFF Research Database (Denmark)

    Mics, Zoltán; D’Angio, Andrea; Jensen, Søren A.

    2013-01-01

    In a series of systematic optical pump–terahertz probe experiments, we study the density-dependent electron scattering rate in photoexcited GaAs in the regime of strong carrier diffusion. The terahertz frequency-resolved transient sheet conductivity spectra are perfectly described by the Drude...... model, directly yielding the electron scattering rates. A diffusion model is applied to determine the spatial extent of the photoexcited electron-hole gas at each moment after photoexcitation, yielding the time-dependent electron density, and hence the density-dependent electron scattering time. We find...

  13. Strongly anisotropic spin-orbit splitting in a two-dimensional electron gas

    DEFF Research Database (Denmark)

    Michiardi, Matteo; Bianchi, Marco; Dendzik, Maciej

    2015-01-01

    Near-surface two-dimensional electron gases on the topological insulator Bi$_2$Te$_2$Se are induced by electron doping and studied by angle-resolved photoemission spectroscopy. A pronounced spin-orbit splitting is observed for these states. The $k$-dependent splitting is strongly anisotropic to a...

  14. Subgap Two-Photon States in Polycyclic Aromatic Hydrocarbons: Evidence for Strong Electron Correlations

    OpenAIRE

    Aryanpour, K.; Roberts, A.; Sandhu, A.; Rathore, R.; Shukla, A.; Mazumdar, S.

    2013-01-01

    Strong electron correlation effects in the photophysics of quasi-one-dimensional $\\pi$-conjugated organic systems such as polyenes, polyacetylenes, polydiacetylenes, etc., have been extensively studied. Far less is known on correlation effects in two-dimensional $\\pi$-conjugated systems. Here we present theoretical and experimental evidence for moderate repulsive electron-electron interactions in a number of finite polycyclic aromatic hydrocarbon molecules with $D_{6h}$ symmetry. We show that...

  15. Strong coupling of a single electron in silicon to a microwave photon

    Science.gov (United States)

    Mi, X.; Cady, J. V.; Zajac, D. M.; Deelman, P. W.; Petta, J. R.

    2017-01-01

    Silicon is vital to the computing industry because of the high quality of its native oxide and well-established doping technologies. Isotopic purification has enabled quantum coherence times on the order of seconds, thereby placing silicon at the forefront of efforts to create a solid-state quantum processor. We demonstrate strong coupling of a single electron in a silicon double quantum dot to the photonic field of a microwave cavity, as shown by the observation of vacuum Rabi splitting. Strong coupling of a quantum dot electron to a cavity photon would allow for long-range qubit coupling and the long-range entanglement of electrons in semiconductor quantum dots.

  16. Dynamics of valence-shell electrons and nuclei probed by strong-field holography and rescattering

    Science.gov (United States)

    Walt, Samuel G.; Bhargava Ram, Niraghatam; Atala, Marcos; Shvetsov-Shilovski, Nikolay I; von Conta, Aaron; Baykusheva, Denitsa; Lein, Manfred; Wörner, Hans Jakob

    2017-01-01

    Strong-field photoelectron holography and laser-induced electron diffraction (LIED) are two powerful emerging methods for probing the ultrafast dynamics of molecules. However, both of them have remained restricted to static systems and to nuclear dynamics induced by strong-field ionization. Here we extend these promising methods to image purely electronic valence-shell dynamics in molecules using photoelectron holography. In the same experiment, we use LIED and photoelectron holography simultaneously, to observe coupled electronic-rotational dynamics taking place on similar timescales. These results offer perspectives for imaging ultrafast dynamics of molecules on femtosecond to attosecond timescales. PMID:28643771

  17. Spin dynamics of electrons in strong fields studied via bremsstrahlung from a polarized electron beam

    Energy Technology Data Exchange (ETDEWEB)

    Tashenov, Stanislav [Royal Institute of Technology, Stockholm (Sweden); Stockholm University (Sweden); Physikalisches Institut, Universitaet Heidelberg (Germany); Baeck, Torbjoern; Cederwall, Bo; Khaplanov, Anton; Schaessburger, Kai-Uwe [Royal Institute of Technology, Stockholm (Sweden); Barday, Roman; Enders, Joachim; Poltoratska, Yuliya [Institut fuer Kernphysik, Technische Universitaet, Darmstadt (Germany); Surzhykov, Andrey [Physikalisches Institut, Universitaet Heidelberg (Germany); GSI, Helmholtzzentrum fuer Schwerionenforschung GmbH, Darmstadt (Germany)

    2011-07-01

    Linear polarization of the photons emitted in the process of the atomic field electron bremsstrahlung has been studied at the newly developed 100 keV polarized electron source of TU Darmstadt. A correlation between the initial orientation of the electron spin and the degree and the angle of photon linear polarization has been measured for the first time. For this purpose a hard x-ray Compton polarimeter consisting of a segmented high purity germanium detector and an external passive photon scattering target have been applied. Linear polarization sensitive Compton and Rayleigh photon scattering distributions have been sampled by the segmented detector. The observed polarization correlation reveals a precession of the electron spin as it moves in the field of the nucleus. The full-relativistic calculations for the case of radiative recombination into a Rydberg series limit have been corroborated by the measurement. The results of this experiment suggest a new method for electron beam polarimetry.

  18. Strong electron bidirectional anisotropies in the distant tail: ISEE 3 observations of polar rain

    International Nuclear Information System (INIS)

    Baker, D.N.; Bame, S.J.; Feldman, W.C.; Gosling, J.T.; Zwickl, R.D.; Slavin, J.A.; Smith, E.J.

    1986-01-01

    A detailed observational treatment of bidirectional electrons (--50 to 50 eV)in the distant magnetotail (rapprox. >100 R/sub E/) is presented. It is found that electrons in this energy range commonly exhibit strong, field-aligned anisotropies in the tail lobes. Because of large tail motions, the ISEE 3 data provide extensive sampling of both the north and south lobes in rapid succession. These data demonstrate directly the strong asymmetries that exist between the north and south lobes at any one time. The bidirectional fluxes are found to occur predominantly in the lobe directly connected to the sunward interplanetary magnetic field in the open magnetosphere model (north lobe for away sectors and south lobe for toward sectors). Electron anisotropy and magnetic field data are presented which show the transition from unidirectional (sheath) electron populations to bidirectional (lobe) populations. Thus we demonstrate the open nature of the distant magnetopause and show that the source of the higher-energy, bidirectional lobe electrons is the tailward directed electron heat flux population in the distant magnetosheath. Taken together, the present evidence suggests that the bidirectional electrons that we observe in the distant tail are closely related to the polar rain electrons observed previously at lower altitudes. Furthermore, these data provide strong evidence that the distant tail is composed largely of open magnetic field lines in contradistinction to some recently advanced models

  19. Observation of the Avalanche of Runaway Electrons in Air in a Strong Electric Field

    Science.gov (United States)

    Gurevich, A. V.; Mesyats, G. A.; Zybin, K. P.; Yalandin, M. I.; Reutova, A. G.; Shpak, V. G.; Shunailov, S. A.

    2012-08-01

    The generation of an avalanche of runaway electrons is demonstrated for the first time in a laboratory experiment. Two flows of runaway electrons are formed sequentially in an extended air discharge gap at the stage of delay of a pulsed breakdown. The first, picosecond, runaway electron flow is emitted in the cathode region where the field is enhanced. Being accelerated in the gap, this beam generates electrons due to impact ionization. These secondary electrons form a delayed avalanche of runaway electrons if the field is strong enough. The properties of the avalanche correspond to the existing notions about the runaway breakdown in air. The measured current of the avalanche exceeds up to an order the current of the initiating electron beam.

  20. Interacting Electrons and Holes in Quasi-2D Quantum Dots in Strong Magnetic Fields

    Science.gov (United States)

    Hawrylak, P.; Sheng, W.; Cheng, S.-J.

    2004-09-01

    Theory of optical properties of interacting electrons and holes in quasi-2D quantum dots in strong magnetic fields is discussed. In two dimensions and the lowest Landau level, hidden symmetries control the interaction of the interacting system with light. By confining electrons and holes into quantum dots hidden symmetries can be removed and the excitation spectrum of electrons and excitons can be observed. We discuss a theory electronic and of excitonic quantum Hall droplets at a filling factorν=2. For an excitonic quantum Hall droplet the characteristic emission spectra are predicted to be related to the total spin of electron and hole configurations. For the electronic droplet the excitation spectrum of the droplet can be mapped out by measuring the emission for increasing number of electrons.

  1. Interacting electrons and holes in quasi-2D quantum dots in strong magnetic fields

    International Nuclear Information System (INIS)

    Hawrylak, P.; Sheng, W.; Cheng, S.-J.

    2004-01-01

    Theory of optical properties of interacting electrons and holes in quasi-2D quantum dots in strong magnetic fields is discussed. In two dimensions and the lowest Landau level, hidden symmetries control the interaction of the interacting system with light. By confining electrons and holes into quantum dots hidden symmetries can be removed and the excitation spectrum of electrons and excitons can be observed. We discuss a theory electronic and excitonic quantum Hall droplets at a filling factor υ = 2. For an excitonic quantum Hall droplet the characteristic emission spectra are predicted to be related to the total spin of electron and hole configurations. For the electronic droplet the excitation spectrum of the droplet can be mapped out by measuring the emission for increasing number of electrons. (author)

  2. Relativistic quantum dynamics in strong fields: Photon emission from heavy, few-electron ions

    International Nuclear Information System (INIS)

    Fritzsche, S.; Stoehlker, T.

    2005-03-01

    Recent progress in the study of the photon emission from highly-charged heavy ions is reviewed. These investigations show that high-Z ions provide a unique tool for improving the understanding of the electron-electron and electron-photon interaction in the presence of strong fields. Apart from the bound-state transitions, which are accurately described in the framework of quantum electrodynamics, much information has been obtained also from the radiative capture of (quasi-) free electrons by high-Z ions. Many features in the observed spectra hereby confirm the inherently relativistic behavior of even the simplest compound quantum systems in nature. (orig.)

  3. First- versus second-generation electronic cigarettes: predictors of choice and effects on urge to smoke and withdrawal symptoms.

    Science.gov (United States)

    Dawkins, Lynne; Kimber, Catherine; Puwanesarasa, Yasothani; Soar, Kirstie

    2015-04-01

    To (1) estimate predictors of first- versus second-generation electronic cigarette (e-cigarette) choice; and (2) determine whether a second-generation device was (i) superior for reducing urge to smoke and withdrawal symptoms (WS) and (ii) associated with enhanced positive subjective effects. Mixed-effects experimental design. Phase 1: reason for e-cigarette choice was assessed via questionnaire. Phase 2: participants were allocated randomly to first- or second-generation e-cigarette condition. Urge to smoke and WS were measured before and 10 minutes after taking 10 e-cigarette puffs. University of East London, UK. A total of 97 smokers (mean age 26; standard deviation 8.7; 54% female). Single-item urge to smoke scale to assess craving and the Mood and Physical Symptoms Scale (MPSS) to assess WS. Subjective effects included: satisfaction, hit, 'felt like smoking' and 'would use to stop smoking' (yes versus no response). Equal numbers chose each device, but none of the predictor variables (gender, age, tobacco dependence, previous e-cigarette use) accounted for choice. Only baseline urge to smoke/WS predicted urge to smoke/WS 10 minutes after use (B =0.38; P E-cigarette device was not a significant predictor. Those using the second-generation device were more likely to report satisfaction and use in a quit attempt (χ(2)  = 12.10, P =0.001 and χ(2)  = 5.53, P =0.02). First- and second-generation electronic cigarettes appear to be similarly effective in reducing urges to smoke during abstinence, but second-generation devices appear to be more satisfying to users. © 2014 Society for the Study of Addiction.

  4. Synthesis and electroluminescent properties of anthracene derivatives containing electron-withdrawing oxide moieties

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, Jhin-yeong; Na, Eun Jae; Park, Soo Na [Department of Chemistry, Sungkyunkwan University, Suwon, 440-746 (Korea, Republic of); Lee, Seok Jae [Department of Information Display, Hongik University, Seoul, 121-791 (Korea, Republic of); Kim, Young Kwan, E-mail: kimyk@wow.hongik.ac.kr [Department of Information Display, Hongik University, Seoul, 121-791 (Korea, Republic of); Yoon, Seung Soo, E-mail: ssyoon@skku.edu [Department of Chemistry, Sungkyunkwan University, Suwon, 440-746 (Korea, Republic of)

    2014-10-15

    Highlights: • Blue fluorescent material is important for application in full-color displays. • We have synthesized emitters based on anthracene connected with oxide moieties. • 1C shows a highly efficient blue EL emission due to electron-injection property. - Abstract: A series of new blue-emitting materials: (4-(10-(naphthalen-2-yl)anthracen-9-yl)phenyl)(phenyl)methanone (1); 9-(naphthalen-2-yl)-10-(4-((diphenyl)phosphine oxide)phenyl)anthracene (2); 9-(naphthalen-2-yl)-10-(4-(phenylsulfonyl)phenyl)anthracene (3) were designed and synthesized via Suzuki cross-coupling reaction. Multilayer OLEDs were fabricated in the following sequence: ITO (180 nm)/NPB (50 nm)/blue materials 1–3 (30 nm)/TPBi (15 nm)/Liq (2 nm)/Al (100 nm). All devices showed the efficient blue EL emissions. In particular, the device using 1 as an emitter exhibited efficient blue electroluminescent properties with a maximum luminous, power, external quantum efficiency and CIE coordinates of 0.36 cd/A, 0.90 lm/W, 0.55% at 20 mA/cm{sup 2} and (x = 0.16, y = 0.20) at 10.0 V, respectively.

  5. Hyperpolarizabilities of one and two electron ions under strongly coupled plasma

    International Nuclear Information System (INIS)

    Sen, Subhrangsu; Mandal, Puspajit; Kumar Mukherjee, Prasanta; Fricke, Burkhard

    2013-01-01

    Systematic investigations on the hyperpolarizabilities of hydrogen and helium like ions up to nuclear charge Z = 7 under strongly coupled plasma environment have been performed. Variation perturbation theory has been adopted to evaluate such properties for the one and two electron systems. For the two electron systems coupled Hartree-Fock theory, which takes care of partial electron correlation effects, has been utilised. Ion sphere model of the strongly coupled plasma, valid for ionic systems only, has been adopted for estimating the effect of plasma environment on the hyperpolarizability. The calculated free ion hyperpolarizability for all the systems is in good agreement with the existing data. Under confinement hyperpolarizabilities of one and two electron ions show interesting trend with respect to plasma coupling strength.

  6. The thermodynamic spin magnetization of strongly correlated 2d electrons in a silicon inversion layer

    OpenAIRE

    Prus, O.; Yaish, Y.; Reznikov, M.; Sivan, U.; Pudalov, V.

    2002-01-01

    A novel method invented to measure the minute thermodynamic spin magnetization of dilute two dimensional fermions is applied to electrons in a silicon inversion layer. Interplay between the ferromagnetic interaction and disorder enhances the low temperature susceptibility up to 7.5 folds compared with the Pauli susceptibility of non-interacting electrons. The magnetization peaks in the vicinity of the density where transition to strong localization takes place. At the same density, the suscep...

  7. Layered Black Phosphorus: Strongly Anisotropic Magnetic, Electronic, and Electron-Transfer Properties.

    Science.gov (United States)

    Sofer, Zdeněk; Sedmidubský, David; Huber, Štěpán; Luxa, Jan; Bouša, Daniel; Boothroyd, Chris; Pumera, Martin

    2016-03-01

    Layered elemental materials, such as black phosphorus, exhibit unique properties originating from their highly anisotropic layered structure. The results presented herein demonstrate an anomalous anisotropy for the electrical, magnetic, and electrochemical properties of black phosphorus. It is shown that heterogeneous electron transfer from black phosphorus to outer- and inner-sphere molecular probes is highly anisotropic. The electron-transfer rates differ at the basal and edge planes. These unusual properties were interpreted by means of calculations, manifesting the metallic character of the edge planes as compared to the semiconducting properties of the basal plane. This indicates that black phosphorus belongs to a group of materials known as topological insulators. Consequently, these effects render the magnetic properties highly anisotropic, as both diamagnetic and paramagnetic behavior can be observed depending on the orientation in the magnetic field. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Electron cyclotron maser instability (ECMI in strong magnetic guide field reconnection

    Directory of Open Access Journals (Sweden)

    R. A. Treumann

    2017-08-01

    Full Text Available The ECMI model of electromagnetic radiation from electron holes is shown to be applicable to spontaneous magnetic reconnection. We apply it to reconnection in strong current-aligned magnetic guide fields. Such guide fields participate only passively in reconnection, which occurs in the antiparallel components to both sides of the guide-field-aligned current sheets with current carried by kinetic Alfvén waves. Reconnection generates long (the order of hundreds of electron inertial scales electron exhaust regions at the reconnection site X point, which are extended perpendicular to the current and the guide fields. Exhausts contain a strongly density-depleted hot electron component and have properties similar to electron holes. Exhaust electron momentum space distributions are highly deformed, exhibiting steep gradients transverse to both the reconnecting and guide fields. Such properties suggest application of the ECMI mechanism with the fundamental ECMI X-mode emission beneath the nonrelativistic guide field cyclotron frequency in localized source regions. An outline of the mechanism and its prospects is given. Potential applications are the kilometric radiation (AKR in auroral physics, solar radio emissions during flares, planetary emissions and astrophysical scenarios (radiation from stars and compact objects involving the presence of strong magnetic fields and field-aligned currents. Drift of the exhausts along the guide field maps the local field and plasma properties. Escape of radiation from the exhaust and radiation source region still poses a problem. The mechanism can be studied in 2-D particle simulations of strong guide field reconnection which favours 2-D, mapping the deformation of the electron distribution perpendicular to the guide field, and using it in the numerical calculation of the ECMI growth rate. The mechanism suggests also that reconnection in general may become a source of the ECMI with or without guide fields. This is

  9. Electron cyclotron maser instability (ECMI) in strong magnetic guide field reconnection

    Science.gov (United States)

    Treumann, Rudolf A.; Baumjohann, Wolfgang

    2017-08-01

    The ECMI model of electromagnetic radiation from electron holes is shown to be applicable to spontaneous magnetic reconnection. We apply it to reconnection in strong current-aligned magnetic guide fields. Such guide fields participate only passively in reconnection, which occurs in the antiparallel components to both sides of the guide-field-aligned current sheets with current carried by kinetic Alfvén waves. Reconnection generates long (the order of hundreds of electron inertial scales) electron exhaust regions at the reconnection site X point, which are extended perpendicular to the current and the guide fields. Exhausts contain a strongly density-depleted hot electron component and have properties similar to electron holes. Exhaust electron momentum space distributions are highly deformed, exhibiting steep gradients transverse to both the reconnecting and guide fields. Such properties suggest application of the ECMI mechanism with the fundamental ECMI X-mode emission beneath the nonrelativistic guide field cyclotron frequency in localized source regions. An outline of the mechanism and its prospects is given. Potential applications are the kilometric radiation (AKR) in auroral physics, solar radio emissions during flares, planetary emissions and astrophysical scenarios (radiation from stars and compact objects) involving the presence of strong magnetic fields and field-aligned currents. Drift of the exhausts along the guide field maps the local field and plasma properties. Escape of radiation from the exhaust and radiation source region still poses a problem. The mechanism can be studied in 2-D particle simulations of strong guide field reconnection which favours 2-D, mapping the deformation of the electron distribution perpendicular to the guide field, and using it in the numerical calculation of the ECMI growth rate. The mechanism suggests also that reconnection in general may become a source of the ECMI with or without guide fields. This is of particular

  10. Communication: A Jastrow factor coupled cluster theory for weak and strong electron correlation

    International Nuclear Information System (INIS)

    Neuscamman, Eric

    2013-01-01

    We present a Jastrow-factor-inspired variant of coupled cluster theory that accurately describes both weak and strong electron correlation. Compatibility with quantum Monte Carlo allows for variational energy evaluations and an antisymmetric geminal power reference, two features not present in traditional coupled cluster that facilitate a nearly exact description of the strong electron correlations in minimal-basis N 2 bond breaking. In double-ζ treatments of the HF and H 2 O bond dissociations, where both weak and strong correlations are important, this polynomial cost method proves more accurate than either traditional coupled cluster or complete active space perturbation theory. These preliminary successes suggest a deep connection between the ways in which cluster operators and Jastrow factors encode correlation

  11. Observation of strongly forbidden solid effect dynamic nuclear polarization transitions via electron-electron double resonance detected NMR

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Albert A.; Corzilius, Björn; Haze, Olesya; Swager, Timothy M.; Griffin, Robert G., E-mail: rgg@mit.edu [Department of Chemistry and Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

    2013-12-07

    We present electron paramagnetic resonance experiments for which solid effect dynamic nuclear polarization transitions were observed indirectly via polarization loss on the electron. This use of indirect observation allows characterization of the dynamic nuclear polarization (DNP) process close to the electron. Frequency profiles of the electron-detected solid effect obtained using trityl radical showed intense saturation of the electron at the usual solid effect condition, which involves a single electron and nucleus. However, higher order solid effect transitions involving two, three, or four nuclei were also observed with surprising intensity, although these transitions did not lead to bulk nuclear polarization—suggesting that higher order transitions are important primarily in the transfer of polarization to nuclei nearby the electron. Similar results were obtained for the SA-BDPA radical where strong electron-nuclear couplings produced splittings in the spectrum of the indirectly observed solid effect conditions. Observation of high order solid effect transitions supports recent studies of the solid effect, and suggests that a multi-spin solid effect mechanism may play a major role in polarization transfer via DNP.

  12. Small Fermi energy, strong electron-phonon effects and anharmonicity in MgB2

    International Nuclear Information System (INIS)

    Cappelluti, E.; Pietronero, L.

    2007-01-01

    The investigation of the electron-phonon properties in MgB 2 has attracted a huge interest after the discovery of superconductivity with T c 39 K in this compound. Although superconductivity is often described in terms of the conventional Eliashberg theory, properly generalized in the multiband/multigap scenario, important features distinguish MgB 2 from other conventional strong-coupling superconductors. Most important it is the fact that a large part of the total electron-phonon strength seems to be concentrated here in only one phonon mode, the boron-boron E 2g stretching mode. Another interesting property is the small Fermi energy of the σ bands, which are strongly coupled with the E 2g mode. In this contribution, we discuss how the coexistence of both these features give rise to an unconventional phenomenology of the electron-phonon properties

  13. Superoxide radical-mediated photocatalytic oxidation of phenolic compounds over Ag{sup +}/TiO{sub 2}: Influence of electron donating and withdrawing substituents

    Energy Technology Data Exchange (ETDEWEB)

    Xiao, Jiadong [National Engineering Laboratory for Hydrometallurgical Cleaner Production Technology, Beijing Engineering Research Center of Process Pollution Control, Key Laboratory of Green Process and Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Xie, Yongbing, E-mail: ybxie@ipe.ac.cn [National Engineering Laboratory for Hydrometallurgical Cleaner Production Technology, Beijing Engineering Research Center of Process Pollution Control, Key Laboratory of Green Process and Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190 (China); Han, Qingzhen [State Key Laboratory of Multi-phase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190 (China); Cao, Hongbin [National Engineering Laboratory for Hydrometallurgical Cleaner Production Technology, Beijing Engineering Research Center of Process Pollution Control, Key Laboratory of Green Process and Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190 (China); Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin 300072 (China); Wang, Yujiao [Department of Chemical and Biomedical Engineering, University of Science and Technology Beijing (China); Nawaz, Faheem; Duan, Feng [National Engineering Laboratory for Hydrometallurgical Cleaner Production Technology, Beijing Engineering Research Center of Process Pollution Control, Key Laboratory of Green Process and Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190 (China); University of Chinese Academy of Sciences, Beijing 100049 (China)

    2016-03-05

    Highlights: • A weak EWG benefited photocatalytic oxidation of phenols the most. • Phenolic compounds were dominantly oxidized by ·O{sub 2}{sup −}, rather than ·OH, {sup 1}O{sub 2} or h{sup +}. • ·O{sub 2}{sup −} preferred to nucleophilically attack EDG substituted phenols. • ·O{sub 2}{sup −} more likely electrophilically attacked EWG substituted phenols. • ·O{sub 2}{sup −} simultaneously nucleophilically and electrophilically assaulted p-chlorophenol. - Abstract: A comparative study was constructed to correlate the electronic property of the substituents with the degradation rates of phenolic compounds and their oxidation pathways under UV with Ag{sup +}/TiO{sub 2} suspensions. It was verified that a weak electron withdrawing substituent benefited photocatalytic oxidation the most, while an adverse impact appeared when a substituent was present with stronger electron donating or withdrawing ability. The addition of p-benzoquinone dramatically blocked the degradation, confirming superoxide radicals (·O{sub 2}{sup −}) as the dominant photooxidant, rather than hydroxyl radicals, singlet oxygen or positive holes, which was also independent of the substituent. Hammett relationship was established based on pseudo-first-order reaction kinetics, and it revealed two disparate reaction patterns between ·O{sub 2}{sup −} and phenolic compounds, which was further verified by the quantum chemical computation on the frontier molecular orbitals and Mulliken charge distributions of ·O{sub 2}{sup −} and phenolic compounds. It was found that electron donating group (EDG) substituted phenols were more likely nucleophilically attacked by ·O{sub 2}{sup −}, while ·O{sub 2}{sup −} preferred to electrophilically assault electron withdrawing group (EWG) substituted phenols. Exceptionally, electrophilic and nucleophilic attack by ·O{sub 2}{sup −} could simultaneously occur in p-chlorophenol degradation, consequently leading to its highest rate

  14. Superoxide radical-mediated photocatalytic oxidation of phenolic compounds over Ag"+/TiO_2: Influence of electron donating and withdrawing substituents

    International Nuclear Information System (INIS)

    Xiao, Jiadong; Xie, Yongbing; Han, Qingzhen; Cao, Hongbin; Wang, Yujiao; Nawaz, Faheem; Duan, Feng

    2016-01-01

    Highlights: • A weak EWG benefited photocatalytic oxidation of phenols the most. • Phenolic compounds were dominantly oxidized by ·O_2"−, rather than ·OH, "1O_2 or h"+. • ·O_2"− preferred to nucleophilically attack EDG substituted phenols. • ·O_2"− more likely electrophilically attacked EWG substituted phenols. • ·O_2"− simultaneously nucleophilically and electrophilically assaulted p-chlorophenol. - Abstract: A comparative study was constructed to correlate the electronic property of the substituents with the degradation rates of phenolic compounds and their oxidation pathways under UV with Ag"+/TiO_2 suspensions. It was verified that a weak electron withdrawing substituent benefited photocatalytic oxidation the most, while an adverse impact appeared when a substituent was present with stronger electron donating or withdrawing ability. The addition of p-benzoquinone dramatically blocked the degradation, confirming superoxide radicals (·O_2"−) as the dominant photooxidant, rather than hydroxyl radicals, singlet oxygen or positive holes, which was also independent of the substituent. Hammett relationship was established based on pseudo-first-order reaction kinetics, and it revealed two disparate reaction patterns between ·O_2"− and phenolic compounds, which was further verified by the quantum chemical computation on the frontier molecular orbitals and Mulliken charge distributions of ·O_2"− and phenolic compounds. It was found that electron donating group (EDG) substituted phenols were more likely nucleophilically attacked by ·O_2"−, while ·O_2"− preferred to electrophilically assault electron withdrawing group (EWG) substituted phenols. Exceptionally, electrophilic and nucleophilic attack by ·O_2"− could simultaneously occur in p-chlorophenol degradation, consequently leading to its highest rate constant. Possible reactive positions on the phenolic compounds were also detailedly uncovered.

  15. Strong-coupling behaviour of two t - J chains with interchain single-electron hopping

    International Nuclear Information System (INIS)

    Zhang Guangming; Feng Shiping; Yu Lu.

    1994-01-01

    Using the fermion-spin transformation to implement spin-charge separation of constrained electrons, a model of two t - J chains with interchain single-electron hopping is studied by abelian bosonization. After spin-charge decoupling the charge dynamics can be trivially solved, while the spin dynamics is determined by a strong-coupling fixed point where the correlation functions can be calculated explicitly. This is a generalization of the Luther-Emery line for two-coupled t - J chains. The interchain single-electron hopping changes the asymptotic behaviour of the interchain spin-spin correlation functions and the electron Green function, but their exponents are independent of the coupling strength. (author). 25 refs

  16. Existence of a virtual cathode close to a strongly electron emissive wall in low density plasmas

    International Nuclear Information System (INIS)

    Tierno, S. P.; Donoso, J. M.; Domenech-Garret, J. L.; Conde, L.

    2016-01-01

    The interaction between an electron emissive wall, electrically biased in a plasma, is revisited through a simple fluid model. We search for realistic conditions of the existence of a non-monotonic plasma potential profile with a virtual cathode as it is observed in several experiments. We mainly focus our attention on thermionic emission related to the operation of emissive probes for plasma diagnostics, although most conclusions also apply to other electron emission processes. An extended Bohm criterion is derived involving the ratio between the two different electron densities at the potential minimum and at the background plasma. The model allows a phase-diagram analysis, which confirms the existence of the non-monotonic potential profiles with a virtual cathode. This analysis shows that the formation of the potential well critically depends on the emitted electron current and on the velocity at the sheath edge of cold ions flowing from the bulk plasma. As a consequence, a threshold value of the governing parameter is required, in accordance to the physical nature of the electron emission process. The latter is a threshold wall temperature in the case of thermionic electrons. Experimental evidence supports our numerical calculations of this threshold temperature. Besides this, the potential well becomes deeper with increasing electron emission, retaining a fraction of the released current which limits the extent of the bulk plasma perturbation. This noninvasive property would explain the reliable measurements of plasma potential by using the floating potential method of emissive probes operating in the so-called strong emission regime

  17. Existence of a virtual cathode close to a strongly electron emissive wall in low density plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Tierno, S. P., E-mail: sp.tierno@upm.es; Donoso, J. M.; Domenech-Garret, J. L.; Conde, L. [Department of Applied Physics, E.T.S.I. Aeronáutica y del Espacio. Universidad Politécnica de Madrid, 28040 Madrid (Spain)

    2016-01-15

    The interaction between an electron emissive wall, electrically biased in a plasma, is revisited through a simple fluid model. We search for realistic conditions of the existence of a non-monotonic plasma potential profile with a virtual cathode as it is observed in several experiments. We mainly focus our attention on thermionic emission related to the operation of emissive probes for plasma diagnostics, although most conclusions also apply to other electron emission processes. An extended Bohm criterion is derived involving the ratio between the two different electron densities at the potential minimum and at the background plasma. The model allows a phase-diagram analysis, which confirms the existence of the non-monotonic potential profiles with a virtual cathode. This analysis shows that the formation of the potential well critically depends on the emitted electron current and on the velocity at the sheath edge of cold ions flowing from the bulk plasma. As a consequence, a threshold value of the governing parameter is required, in accordance to the physical nature of the electron emission process. The latter is a threshold wall temperature in the case of thermionic electrons. Experimental evidence supports our numerical calculations of this threshold temperature. Besides this, the potential well becomes deeper with increasing electron emission, retaining a fraction of the released current which limits the extent of the bulk plasma perturbation. This noninvasive property would explain the reliable measurements of plasma potential by using the floating potential method of emissive probes operating in the so-called strong emission regime.

  18. Existence of a virtual cathode close to a strongly electron emissive wall in low density plasmas

    Science.gov (United States)

    Tierno, S. P.; Donoso, J. M.; Domenech-Garret, J. L.; Conde, L.

    2016-01-01

    The interaction between an electron emissive wall, electrically biased in a plasma, is revisited through a simple fluid model. We search for realistic conditions of the existence of a non-monotonic plasma potential profile with a virtual cathode as it is observed in several experiments. We mainly focus our attention on thermionic emission related to the operation of emissive probes for plasma diagnostics, although most conclusions also apply to other electron emission processes. An extended Bohm criterion is derived involving the ratio between the two different electron densities at the potential minimum and at the background plasma. The model allows a phase-diagram analysis, which confirms the existence of the non-monotonic potential profiles with a virtual cathode. This analysis shows that the formation of the potential well critically depends on the emitted electron current and on the velocity at the sheath edge of cold ions flowing from the bulk plasma. As a consequence, a threshold value of the governing parameter is required, in accordance to the physical nature of the electron emission process. The latter is a threshold wall temperature in the case of thermionic electrons. Experimental evidence supports our numerical calculations of this threshold temperature. Besides this, the potential well becomes deeper with increasing electron emission, retaining a fraction of the released current which limits the extent of the bulk plasma perturbation. This noninvasive property would explain the reliable measurements of plasma potential by using the floating potential method of emissive probes operating in the so-called strong emission regime.

  19. Theory of a four-electron 2-D system in a strong magnetic field

    International Nuclear Information System (INIS)

    Yuandong Dai; Bingjian Ni; Fusui Liu.

    1985-10-01

    An orthogonal and complete set for relative motion of four-electron 2-D system in strong magnetic field is given, the energy of ground state of relative motion is calculated. This paper also calculates the energy of ground state whose maximum of single electron angular momentum is limited by the degeneracy under a given magnetic field, obtains the energy minimums corresponding to a fractional quantized Hall effect of 2/5, 2/7, and from it the physical meaning of 'magic number' is interpreted. (author)

  20. Few-Photon Multiple Ionization of Ne and Ar by Strong Free-Electron-Laser Pulses

    International Nuclear Information System (INIS)

    Moshammer, R.; Jiang, Y. H.; Rudenko, A.; Ergler, Th.; Schroeter, C. D.; Luedemann, S.; Zrost, K.; Dorn, A.; Ferger, T.; Kuehnel, K. U.; Ullrich, J.; Foucar, L.; Titze, J.; Jahnke, T.; Schoeffler, M.; Doerner, R.; Fischer, D.; Weber, T.; Zouros, T. J. M.; Duesterer, S.

    2007-01-01

    Few-photon multiple ionization of Ne and Ar atoms by strong vacuum ultraviolet laser pulses from the free-electron laser at Hamburg was investigated differentially with the Heidelberg reaction microscope. The light-intensity dependence of Ne 2+ production reveals the dominance of nonsequential two-photon double ionization at intensities of I 12 W/cm 2 and significant contributions of three-photon ionization as I increases. Ne 2+ recoil-ion-momentum distributions suggest that two electrons absorbing ''instantaneously'' two photons are ejected most likely into opposite hemispheres with similar energies

  1. Strong non-radial propagation of energetic electrons in solar corona

    Science.gov (United States)

    Klassen, A.; Dresing, N.; Gómez-Herrero, R.; Heber, B.; Veronig, A.

    2018-06-01

    Analyzing the sequence of solar energetic electron events measured at both STEREO-A (STA) and STEREO-B (STB) spacecraft during 17-21 July 2014, when their orbital separation was 34°, we found evidence of a strong non-radial electron propagation in the solar corona below the solar wind source surface. The impulsive electron events were associated with recurrent flare and jet (hereafter flare/jet) activity at the border of an isolated coronal hole situated close to the solar equator. We have focused our study on the solar energetic particle (SEP) event on 17 July 2014, during which both spacecraft detected a similar impulsive and anisotropic energetic electron event suggesting optimal connection of both spacecraft to the parent particle source, despite the large angular separation between the parent flare and the nominal magnetic footpoints on the source surface of STA and STB of 68° and 90°, respectively. Combining the remote-sensing extreme ultraviolet (EUV) observations, in-situ plasma, magnetic field, and energetic particle data we investigated and discuss here the origin and the propagation trajectory of energetic electrons in the solar corona. We find that the energetic electrons in the energy range of 55-195 keV together with the associated EUV jet were injected from the flare site toward the spacecraft's magnetic footpoints and propagate along a strongly non-radial and inclined magnetic field below the source surface. From stereoscopic (EUV) observations we estimated the inclination angle of the jet trajectory and the respective magnetic field of 63° ± 11° relative to the radial direction. We show how the flare accelerated electrons reach very distant longitudes in the heliosphere, when the spacecraft are nominally not connected to the particle source. This example illustrates how ballistic backmapping can occasionally fail to characterize the magnetic connectivity during SEP events. This finding also provides an additional mechanism (one among others

  2. Strong quadrupole interaction in electron paramagnetic resonance. Study of the indium hexacyanide (III) in KCl irradiated with electrons

    International Nuclear Information System (INIS)

    Vugman, N.V.

    1973-08-01

    The radiation effects in ]Ir III (CN) 6 ] 3- diamagnetic complexe inserted in the KCl lattice and irradiated with electrons of 2MeV by electron spin resonance (ESR) are analysed. Formulas for g and A tensors in the ligand field approximation, are derivated to calculate non coupling electron density in the metal. The X polarization field of inner shells is positive, indicating a 6s function mixture in the non coupling electron molecular orbital. The observed hyperfine structure is assigned to 4 equivalent nitrogen and one non equivalent nitrogen. This hypothesis is verified by experience of isotope substitution with 15 N. The s and p spin density in ligands are calculated and discussed in terms of molecular obitals. The effects of strong quadrupole interaction into the EPR spectra of ]Ir II (CN) 5 ] 3- complex are analysed by MAGNSPEC computer program to diagonalize the Spin Hamiltonian of the system. Empiric rules for EPR espectrum interpretation with strong quadrupole interaction. A review of EPR technique and a review of main concepts of crystal-field and ligand field theories, are also presented. (M.C.K.) [pt

  3. Dielectric response of a relativistic degenerate electron plasma in a strong magnetic field

    International Nuclear Information System (INIS)

    Delsante, A.E.; Frankel, N.E.

    1979-01-01

    The longitudinal dielectric response of a relativistic ultradegenerate electron plasma in a strong magnetic field is obtained via a relativistic generalization of the Hartree self-consistent field method. Dispersion relations and damping conditions for plasma oscillations both parallel and perpendicular to the magnetic field are obtained. Detailed results for the zero-field case, and applications to white dwarf stars and pulsars are given

  4. Truncated exponential-rigid-rotor model for strong electron and ion rings

    International Nuclear Information System (INIS)

    Larrabee, D.A.; Lovelace, R.V.; Fleischmann, H.H.

    1979-01-01

    A comprehensive study of exponential-rigid-rotor equilibria for strong electron and ion rings indicates the presence of a sizeable percentage of untrapped particles in all equilibria with aspect-ratios R/a approximately <4. Such aspect-ratios are required in fusion-relevant rings. Significant changes in the equilibria are observed when untrapped particles are excluded by the use of a truncated exponential-rigid-rotor distribution function. (author)

  5. Strongly correlated electron systems and neutron scattering. Magnetism, superconductivity, structural phase transition

    Energy Technology Data Exchange (ETDEWEB)

    Katano, Susumu [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1998-03-01

    Neutron scattering experiments in our group on strongly correlated electron systems are reviewed Metal-insulator transitions caused by structural phase transitions in (La{sub 1-x}Sr{sub x}) MnO{sub 3}, a novel magnetic transition in the CeP compound, correlations between antiferromagnetism and superconductivity in UPd{sub 2}Al{sub 3} and so forth are discussed. Here, in this note, the phase transition of Mn-oxides was mainly described. (author)

  6. Strong field QED in lepton colliders and electron/laser interactions

    Science.gov (United States)

    Hartin, Anthony

    2018-05-01

    The studies of strong field particle physics processes in electron/laser interactions and lepton collider interaction points (IPs) are reviewed. These processes are defined by the high intensity of the electromagnetic fields involved and the need to take them into account as fully as possible. Thus, the main theoretical framework considered is the Furry interaction picture within intense field quantum field theory. In this framework, the influence of a background electromagnetic field in the Lagrangian is calculated nonperturbatively, involving exact solutions for quantized charged particles in the background field. These “dressed” particles go on to interact perturbatively with other particles, enabling the background field to play both macroscopic and microscopic roles. Macroscopically, the background field starts to polarize the vacuum, in effect rendering it a dispersive medium. Particles encountering this dispersive vacuum obtain a lifetime, either radiating or decaying into pair particles at a rate dependent on the intensity of the background field. In fact, the intensity of the background field enters into the coupling constant of the strong field quantum electrodynamic Lagrangian, influencing all particle processes. A number of new phenomena occur. Particles gain an intensity-dependent rest mass shift that accounts for their presence in the dispersive vacuum. Multi-photon events involving more than one external field photon occur at each vertex. Higher order processes which exchange a virtual strong field particle resonate via the lifetimes of the unstable strong field states. Two main arenas of strong field physics are reviewed; those occurring in relativistic electron interactions with intense laser beams, and those occurring in the beam-beam physics at the interaction point of colliders. This review outlines the theory, describes its significant novel phenomenology and details the experimental schema required to detect strong field effects and the

  7. Some new features of electron density irregularities over SHAR during strong spread F

    Directory of Open Access Journals (Sweden)

    S. Raizada

    Full Text Available An RH-560 rocket flight was conducted from Sriharikota rocket range (SHAR (14°N, 80°E, dip latitude 5.5°N to study electron density and electric field irregularities during spread F. The rocket was launched at 2130 local time (LT and it attained an apogee of 348 km. Results of electron density fluctuations are presented here. Two extremely sharp layers of very high electron density were observed at 105 and 130 km. The electron density increase in these layers was by a factor of 50 in a vertical extent of 10 km. Large depletions in electron density were observed around 175 and 238 km. Both sharp layers as well as depletions were observed also during the descent. The presence of sharp layers and depletions during the ascent and the descent of the rocket as well as an order of magnitude less electron density, in 150-300 km region during the descent, indicate the presence of strong large-scale horizontal gradients in the electron density. Some of the valley region irregularities (165-178 km, in the intermediate scale size range, observed during this flight, show spectral peaks at 2 km and can be interpreted in terms of the image striation theory suggested by Vickrey et al. The irregularities at 176 km do not exhibit any peak at kilometer scales and appear to be of new type. The growth rate of intermediate scale size irregularities, produced through generalized Rayleigh Taylor instability, was calculated for the 200-330 km altitude, using observed values of electron density gradients and an assumed vertically downward wind of 20 ms-1. These growth rate calculations suggest that the observed irregularities could be produced by the gradient drift instability.

    Key words: Ionosphere (equatorial ionosphere; ionospheric irregularities - Radio science (ionospheric physics

  8. Some new features of electron density irregularities over SHAR during strong spread F

    Directory of Open Access Journals (Sweden)

    S. Raizada

    2000-02-01

    Full Text Available An RH-560 rocket flight was conducted from Sriharikota rocket range (SHAR (14°N, 80°E, dip latitude 5.5°N to study electron density and electric field irregularities during spread F. The rocket was launched at 2130 local time (LT and it attained an apogee of 348 km. Results of electron density fluctuations are presented here. Two extremely sharp layers of very high electron density were observed at 105 and 130 km. The electron density increase in these layers was by a factor of 50 in a vertical extent of 10 km. Large depletions in electron density were observed around 175 and 238 km. Both sharp layers as well as depletions were observed also during the descent. The presence of sharp layers and depletions during the ascent and the descent of the rocket as well as an order of magnitude less electron density, in 150-300 km region during the descent, indicate the presence of strong large-scale horizontal gradients in the electron density. Some of the valley region irregularities (165-178 km, in the intermediate scale size range, observed during this flight, show spectral peaks at 2 km and can be interpreted in terms of the image striation theory suggested by Vickrey et al. The irregularities at 176 km do not exhibit any peak at kilometer scales and appear to be of new type. The growth rate of intermediate scale size irregularities, produced through generalized Rayleigh Taylor instability, was calculated for the 200-330 km altitude, using observed values of electron density gradients and an assumed vertically downward wind of 20 ms-1. These growth rate calculations suggest that the observed irregularities could be produced by the gradient drift instability.Key words: Ionosphere (equatorial ionosphere; ionospheric irregularities - Radio science (ionospheric physics

  9. Anomalous Behavior of Electronic Heat Capacity of Strongly Correlated Iron Monosilicide

    Science.gov (United States)

    Povzner, A. A.; Volkov, A. G.; Nogovitsyna, T. A.

    2018-04-01

    The paper deals with the electronic heat capacity of iron monosilicide FeSi subjected to semiconductor-metal thermal transition during which the formation of its spintronic properties is observed. The proposed model which considers pd-hybridization of strongly correlated d-electrons with non-correlated p-electrons, demonstrates a connection of their contribution to heat capacity in the insulator phase with paramagnon effects and fluctuations of occupation numbers for p- and d-states. In a slitless state, the temperature curve of heat capacity is characterized by a maximum appeared due to normalization of the electron density of states using fluctuating exchange fields. At higher temperatures, a linear growth in heat capacity occurs due to paramagnon effects. The correlation between the model parameters and the first-principles calculation provides the electron contribution to heat capacity, which is obtained from the experimental results on phonon heat capacity. Anharmonicity of phonons is connected merely with the thermal expansion of the crystal lattice.

  10. Adler Award Lecture: Fermi-Liquid Instabilities in Strongly Correlated f-Electron Materials.^*

    Science.gov (United States)

    Maple, M. Brian

    1996-03-01

    Strongly correlated f-electron materials are replete with novel electronic states and phenomena ; e. g. , a metallic ``heavy electron'' state with a quasiparticle effective mass of several hundred times the free electron mass, anisotropic superconductivity with an energy gap that may vanish at points or along lines on the Fermi surface, the coexistence of superconductivity and antiferromagnetism over different parts of the Fermi surface, multiple superconducting phases in the hyperspace of chemical composition, temperature, pressure, and magnetic field, and an insulating phase, in so-called ``hybridization gap semiconductors'' or ``Kondo insulators'', with a small energy gap of only a few meV. During the last several years, a new low temperature non-Fermi-liquid (NFL) state has been observed in a new class of strongly correlated f-electron materials which currently consists of certain Ce and U intermetallics into which a nonmagnetic element has been substituted.(M. B. Maple et al./) , J. Low Temp. Phys. 99 , 223 (1995). The Ce and U ions have partially-filled f-electron shells and carry magnetic dipole or electric quadrupole moments which interact with the spins and charges of the conduction electrons and can participate in magnetic or quadrupolar ordering at low temperatures. The physical properties of these materials exhibit weak power law or logarithmic divergences in temperature and suggest the existence of a critical point at T=0 K. Possible origins of the 0 K critical point include an unconventional moment compensation process, such as a multichannel Kondo effect, and fluctuations of the order parameter in the vicinity of a 0 K second order phase transition. In some systems, such as Y_1-xU_xPd 3 and U_1-xTh_xPd _2Al 3 , the NFL characteristics appear to be single ion effects since they persist to low concentrations of f-moments, whereas in other systems, such as CeCu _5.9Au _0.1 , the NFL behavior seems to be associated with interactions between the f

  11. Theoretical Investigation on Charge Transfer Properties of 1,3,5-Tripyrrolebenzene (TPB and its Derivatives with Electron-withdrawing Substituents

    Directory of Open Access Journals (Sweden)

    Yong Hu

    2016-06-01

    Full Text Available The electronic structures and charge transport properties of 1,3,5-tripyrrolebenzene (TPB and its substituted derivatives with –F and –CN groups have been investigated by DFT calculations in combination with the Marcus hopping model. The dimer geometry was optimized by density functional theory method with dispersion force correction being included (DFT-D. Consequently, the charge transfer integral was evaluated. The calculation results show that the introduction of electron-withdrawing substituents does not significantly change the bond lengths and molecular symmetry of TPB, but lower the coplanarity between the pyrrole and benzene rings, especially in the case of CN substitution. Meanwhile, the introduction of electron-withdrawing groups can decrease the energy of the frontier molecular orbital and enhance the air stability. Fluorination makes the λe increase obviously while cyanation dose not. Generally speaking, the λe values of the title compounds are larger than their λh. Except for compounds 6 and 9, all others keep the face to face packing or have a slight slip in dimers, but the center of mass distances increase after fluorination or cyanation due to the distortion of the monomer’s coplanarity. The predicted quasi-one-dimensional electron mobility of the dimers is up to 0.433 cm2 V-1 s-1 at 298.15 K. The electron injection barriers of 2 and 7 are lower than that of TPB. The TPB derivatives of 1, 2, and 7 are potential n-channel materials with the high electron mobility. This work is licensed under a Creative Commons Attribution 4.0 International License.

  12. Photoinduced Electron Transfer in the Strong Coupling Regime: Waveguide-Plasmon Polaritons.

    Science.gov (United States)

    Zeng, Peng; Cadusch, Jasper; Chakraborty, Debadi; Smith, Trevor A; Roberts, Ann; Sader, John E; Davis, Timothy J; Gómez, Daniel E

    2016-04-13

    Reversible exchange of photons between a material and an optical cavity can lead to the formation of hybrid light-matter states where material properties such as the work function [ Hutchison et al. Adv. Mater. 2013 , 25 , 2481 - 2485 ], chemical reactivity [ Hutchison et al. Angew. Chem., Int. Ed. 2012 , 51 , 1592 - 1596 ], ultrafast energy relaxation [ Salomon et al. Angew. Chem., Int. Ed. 2009 , 48 , 8748 - 8751 ; Gomez et al. J. Phys. Chem. B 2013 , 117 , 4340 - 4346 ], and electrical conductivity [ Orgiu et al. Nat. Mater. 2015 , 14 , 1123 - 1129 ] of matter differ significantly to those of the same material in the absence of strong interactions with the electromagnetic fields. Here we show that strong light-matter coupling between confined photons on a semiconductor waveguide and localized plasmon resonances on metal nanowires modifies the efficiency of the photoinduced charge-transfer rate of plasmonic derived (hot) electrons into accepting states in the semiconductor material. Ultrafast spectroscopy measurements reveal a strong correlation between the amplitude of the transient signals, attributed to electrons residing in the semiconductor and the hybridization of waveguide and plasmon excitations.

  13. Bifurcation analysis for ion acoustic waves in a strongly coupled plasma including trapped electrons

    Science.gov (United States)

    El-Labany, S. K.; El-Taibany, W. F.; Atteya, A.

    2018-02-01

    The nonlinear ion acoustic wave propagation in a strongly coupled plasma composed of ions and trapped electrons has been investigated. The reductive perturbation method is employed to derive a modified Korteweg-de Vries-Burgers (mKdV-Burgers) equation. To solve this equation in case of dissipative system, the tangent hyperbolic method is used, and a shock wave solution is obtained. Numerical investigations show that, the ion acoustic waves are significantly modified by the effect of polarization force, the trapped electrons and the viscosity coefficients. Applying the bifurcation theory to the dynamical system of the derived mKdV-Burgers equation, the phase portraits of the traveling wave solutions of both of dissipative and non-dissipative systems are analyzed. The present results could be helpful for a better understanding of the waves nonlinear propagation in a strongly coupled plasma, which can be produced by photoionizing laser-cooled and trapped electrons [1], and also in neutron stars or white dwarfs interior.

  14. Strongly correlated electrons at high pressure: an approach by inelastic X-Ray scattering

    International Nuclear Information System (INIS)

    Rueff, J.P.

    2007-06-01

    Inelastic X-ray scattering (IXS) and associated methods has turn out to be a powerful alternative for high-pressure physics. It is an all-photon technique fully compatible with high-pressure environments and applicable to a vast range of materials. Standard focalization of X-ray in the range of 100 microns is typical of the sample size in the pressure cell. Our main aim is to provide an overview of experimental results obtained by IXS under high pressure in 2 classes of materials which have been at the origin of the renewal of condensed matter physics: strongly correlated transition metal oxides and rare-earth compounds. Under pressure, d and f-electron materials show behaviors far more complex that what would be expected from a simplistic band picture of electron delocalization. These spectroscopic studies have revealed unusual phenomena in the electronic degrees of freedom, brought up by the increased density, the changes in the charge-carrier concentration, the over-lapping between orbitals, and hybridization under high pressure conditions. Particularly we discuss about pressure induced magnetic collapse and metal-insulator transitions in 3d compounds and valence fluctuations phenomena in 4f and 5f compounds. Thanks to its superior penetration depth, chemical selectivity and resonant enhancement, resonant inelastic X-ray scattering has appeared extremely well suited to high pressure physics in strongly correlated materials. (A.C.)

  15. Charging dynamics and strong localization of a two-dimensional electron cloud

    International Nuclear Information System (INIS)

    Dianoux, R; Smilde, H J H; Marchi, F; Buffet, N; Mur, P; Comin, F; Chevrier, J

    2007-01-01

    The dynamics of charge injection in silicon nanocrystals embedded in a silicon dioxide matrix is studied using electrostatic force microscopy. We show that the presence of silicon nanocrystals with a density of 10 11 cm -2 is essential for strong localization of charges, and results in exceptional charge retention properties compared to nanocrystal-free SiO 2 samples. In both systems, a logarithmic dependence of the diameter of the charged area on the injection time is experimentally observed on a timescale between 0.1 and 10 s (voltage≤10 V). A field-emission injection, limited by Coulomb blockade and a lateral charge spreading due to a repulsive radial electric field are used to model the sample charging. Once the tip is retracted, the electron cloud is strongly confined in the nanocrystals and remains static

  16. Semiclassical magnetotransport in strongly spin-orbit coupled Rashba two-dimensional electron systems

    Science.gov (United States)

    Xiao, Cong; Li, Dingping

    2016-06-01

    Semiclassical magnetoelectric and magnetothermoelectric transport in strongly spin-orbit coupled Rashba two-dimensional electron systems is investigated. In the presence of a perpendicular classically weak magnetic field and short-range impurity scattering, we solve the linearized Boltzmann equation self-consistently. Using the solution, it is found that when Fermi energy E F locates below the band crossing point (BCP), the Hall coefficient is a nonmonotonic function of electron density n e and not inversely proportional to n e. While the magnetoresistance (MR) and Nernst coefficient vanish when E F locates above the BCP, non-zero MR and enhanced Nernst coefficient emerge when E F decreases below the BCP. Both of them are nonmonotonic functions of E F below the BCP. The different semiclassical magnetotransport behaviors between the two sides of the BCP can be helpful to experimental identifications of the band valley regime and topological change of Fermi surface in considered systems.

  17. Semiclassical magnetotransport in strongly spin–orbit coupled Rashba two-dimensional electron systems

    International Nuclear Information System (INIS)

    Xiao, Cong; Li, Dingping

    2016-01-01

    Semiclassical magnetoelectric and magnetothermoelectric transport in strongly spin–orbit coupled Rashba two-dimensional electron systems is investigated. In the presence of a perpendicular classically weak magnetic field and short-range impurity scattering, we solve the linearized Boltzmann equation self-consistently. Using the solution, it is found that when Fermi energy E F locates below the band crossing point (BCP), the Hall coefficient is a nonmonotonic function of electron density n e and not inversely proportional to n e . While the magnetoresistance (MR) and Nernst coefficient vanish when E F locates above the BCP, non-zero MR and enhanced Nernst coefficient emerge when E F decreases below the BCP. Both of them are nonmonotonic functions of E F below the BCP. The different semiclassical magnetotransport behaviors between the two sides of the BCP can be helpful to experimental identifications of the band valley regime and topological change of Fermi surface in considered systems. (paper)

  18. Electron-muon correlation as a new probe of strongly interacting quark-gluon plasma

    International Nuclear Information System (INIS)

    Akamatsu, Yukinao; Hatsuda, Tetsuo; Hirano, Tetsufumi

    2009-01-01

    As a new and clean probe to the strongly interacting quark-gluon plasma (sQGP), we propose an azimuthal correlation of an electron and a muon that originate from the semileptonic decay of charm and bottom quarks. By solving the Langevin equation for the heavy quarks under the hydrodynamic evolution of the hot plasma, we show that substantial quenching of the away-side peak in the electron-muon correlation can be seen if the sQGP drag force acting on heavy quarks is large enough as suggested from the gauge/gravity correspondence. The effect could be detected in high-energy heavy ion collisions at the Relativistic Heavy Ion Collider and the Large Hadron Collider.

  19. Direct Visualization of Valence Electron Motion Using Strong-Field Photoelectron Holography

    Science.gov (United States)

    He, Mingrui; Li, Yang; Zhou, Yueming; Li, Min; Cao, Wei; Lu, Peixiang

    2018-03-01

    Watching the valence electron move in molecules on its intrinsic timescale has been one of the central goals of attosecond science and it requires measurements with subatomic spatial and attosecond temporal resolutions. The time-resolved photoelectron holography in strong-field tunneling ionization holds the promise to access this realm. However, it remains to be a challenging task hitherto. Here we reveal how the information of valence electron motion is encoded in the hologram of the photoelectron momentum distribution (PEMD) and develop a novel approach of retrieval. As a demonstration, applying it to the PEMDs obtained by solving the time-dependent Schrödinger equation for the prototypical molecule H2+ , the attosecond charge migration is directly visualized with picometer spatial and attosecond temporal resolutions. Our method represents a general approach for monitoring attosecond charge migration in more complex polyatomic and biological molecules, which is one of the central tasks in the newly emerging attosecond chemistry.

  20. Regular and chaotic motion of two dimensional electrons in a strong magnetic field

    International Nuclear Information System (INIS)

    Bar-Lev, Oded; Levit, Shimon.

    1992-05-01

    For two dimensional system of electrons in a strong magnetic field a standard approximation is the projection on a single Landau level. The resulting Hamiltonian is commonly treated semiclassically. An important element in applying the semiclassical approximation is the integrability of the corresponding classical system. We discuss the relevant integrability conditions and give a simple example of a non-integrable system-two interacting electrons in the presence of two impurities-which exhibits a coexistence of regular and chaotic classical motions. Since the inverse of the magnetic field plays the role of the Planck constant in these problems, one has the opportunity to control the 'closeness' of chaotic physical systems to the classical limit. (author)

  1. Intensity dependent waiting time for strong electron trapping events in speckle stimulated raman scatter

    Energy Technology Data Exchange (ETDEWEB)

    Rose, Harvey [Los Alamos National Laboratory; Daughton, W [Los Alamos National Laboratory; Yin, L [Los Alamos National Laboratory

    2009-01-01

    The onset of Stimulated Raman scatter from an intense laser speckle is the simplest experimentally realizable laser-plasma-interaction environment. Despite this data and recent 3D particle simulations, the controlling mechanism at the onset of backscatter in the kinetic regime when strong electron trapping in the daughter Langmuir wave is a dominant nonlinearity is not understood. This paper explores the consequences of assuming that onset is controlled by large thermal fluctuations. A super exponential dependence of mean reflectivity on speckle intensity in the onset regime is predicted.

  2. Electronic structure calculations of atomic transport properties in uranium dioxide: influence of strong correlations

    International Nuclear Information System (INIS)

    Dorado, B.

    2010-09-01

    Uranium dioxide UO 2 is the standard nuclear fuel used in pressurized water reactors. During in-reactor operation, the fission of uranium atoms yields a wide variety of fission products (FP) which create numerous point defects while slowing down in the material. Point defects and FP govern in turn the evolution of the fuel physical properties under irradiation. In this study, we use electronic structure calculations in order to better understand the fuel behavior under irradiation. In particular, we investigate point defect behavior, as well as the stability of three volatile FP: iodine, krypton and xenon. In order to take into account the strong correlations of uranium 5f electrons in UO 2 , we use the DFT+U approximation, based on the density functional theory. This approximation, however, creates numerous metastable states which trap the system and induce discrepancies in the results reported in the literature. To solve this issue and to ensure the ground state is systematically approached as much as possible, we use a method based on electronic occupancy control of the correlated orbitals. We show that the DFT+U approximation, when used with electronic occupancy control, can describe accurately point defect and fission product behavior in UO 2 and provide quantitative information regarding point defect transport properties in the oxide fuel. (author)

  3. Neuromimetic Circuits with Synaptic Devices Based on Strongly Correlated Electron Systems

    Science.gov (United States)

    Ha, Sieu D.; Shi, Jian; Meroz, Yasmine; Mahadevan, L.; Ramanathan, Shriram

    2014-12-01

    Strongly correlated electron systems such as the rare-earth nickelates (R NiO3 , R denotes a rare-earth element) can exhibit synapselike continuous long-term potentiation and depression when gated with ionic liquids; exploiting the extreme sensitivity of coupled charge, spin, orbital, and lattice degrees of freedom to stoichiometry. We present experimental real-time, device-level classical conditioning and unlearning using nickelate-based synaptic devices in an electronic circuit compatible with both excitatory and inhibitory neurons. We establish a physical model for the device behavior based on electric-field-driven coupled ionic-electronic diffusion that can be utilized for design of more complex systems. We use the model to simulate a variety of associate and nonassociative learning mechanisms, as well as a feedforward recurrent network for storing memory. Our circuit intuitively parallels biological neural architectures, and it can be readily generalized to other forms of cellular learning and extinction. The simulation of neural function with electronic device analogs may provide insight into biological processes such as decision making, learning, and adaptation, while facilitating advanced parallel information processing in hardware.

  4. Achieving blue luminescence of Alq3 through the pull-push effect of the electron-withdrawing and electron-donating substituents

    International Nuclear Information System (INIS)

    Shi Minmin; Lin Jiajun; Shi Yuewen; Ouyang Mi; Wang Mang; Chen Hongzheng

    2009-01-01

    A novel blue-emissive Alq 3 derivative, tris-(4-methyl-6-fluoro-8-hydroxyquinoline) aluminum (6), has been designed and prepared. Because the strong electronegative F atom at 6-position lowers the HOMO significantly and the weak electron-donating methyl group at 4-position retains the drop of the LUMO, the band gap of 6 is broadened, and a blue-shift by 53 nm of the emission peak (λ em ) with substantially enhanced intensity is demonstrated when compared to that of Alq 3 . It is also found that 6 possesses good thermal stability and solubility in common solvents. Through theoretical simulations of the frontier orbitals, it is disclosed that 6's λ em can be blue-shifted further if methyl is replaced with a stronger electron-donating substituent, such as methoxy or N,N'-dimethylamino group.

  5. Control and dynamics of attosecond electron wave packets in strong laser fields

    International Nuclear Information System (INIS)

    Johnsson, P.; Remetter, T.; Varju, K.; L'Huillier; Lopez-Martens, R.; Valentin, C.; Balcou, P.; Kazamias, S.; Mauritsson, J.; Gaarde, M.B.; Schafer, K.J.; Mairess, Y.; Wabnitz, H.; Boutu, W.; Salieres, P.

    2005-01-01

    Full text: Trains of attosecond pulses, emerging from the phase-locking of high-order harmonics generated in a strong laser field are now being routinely produced and characterized in a few laser laboratories. Attosecond pulse trains (APTs) are flexible attosecond sources, since the amplitude and relative phase of the spectral components (the harmonics) can be tailored, allowing us to vary both the duration and the carrier frequency of the pulses. Attosecond pulses interacting with a gas of atoms generate electron wave packets (EWPs), which are temporally localized with approximately the same duration as the attosecond pulses. In contrast to the tunneling electron wave packets giving rise to processes such as high-order harmonic generation and above-threshold-ionization (ATI), the properties of these EWPs are inherited from the attosecond pulses through the single-photon ionization step. Thus the energy and temporal characteristics of the EWPs can be varied independently of the process under investigation, by controlling the properties of the attosecond pulses. This talk will describe two recent experiments done in Lund. First we report on the generation, compression and delivery on target of ultrashort extreme-ultraviolet light pulses using external amplitude and phase control. The APT is synthesized from the 13 th to 35 th harmonics of a 35 fs Ti:sapphire laser. The harmonics are generated by focusing the laser beam into a window-less gas cell, filled with argon. To achieve the required on-target attosecond pulses, the harmonics are filtered spatially, using a fixed aperture, and spectrally using aluminum filters. The aluminum filters also serve the purpose of compressing the attosecond pulses, using the negative group-delay dispersion of aluminum to compensate for the intrinsic positive chirp of the attosecond pulses. This experiment demonstrates a practical method for the synthesis and control of attosecond waveforms, and in this case the production of pulses

  6. Strong Depletion in Hybrid Perovskite p-n Junctions Induced by Local Electronic Doping.

    Science.gov (United States)

    Ou, Qingdong; Zhang, Yupeng; Wang, Ziyu; Yuwono, Jodie A; Wang, Rongbin; Dai, Zhigao; Li, Wei; Zheng, Changxi; Xu, Zai-Quan; Qi, Xiang; Duhm, Steffen; Medhekar, Nikhil V; Zhang, Han; Bao, Qiaoliang

    2018-04-01

    A semiconductor p-n junction typically has a doping-induced carrier depletion region, where the doping level positively correlates with the built-in potential and negatively correlates with the depletion layer width. In conventional bulk and atomically thin junctions, this correlation challenges the synergy of the internal field and its spatial extent in carrier generation/transport. Organic-inorganic hybrid perovskites, a class of crystalline ionic semiconductors, are promising alternatives because of their direct badgap, long diffusion length, and large dielectric constant. Here, strong depletion in a lateral p-n junction induced by local electronic doping at the surface of individual CH 3 NH 3 PbI 3 perovskite nanosheets is reported. Unlike conventional surface doping with a weak van der Waals adsorption, covalent bonding and hydrogen bonding between a MoO 3 dopant and the perovskite are theoretically predicted and experimentally verified. The strong hybridization-induced electronic coupling leads to an enhanced built-in electric field. The large electric permittivity arising from the ionic polarizability further contributes to the formation of an unusually broad depletion region up to 10 µm in the junction. Under visible optical excitation without electrical bias, the lateral diode demonstrates unprecedented photovoltaic conversion with an external quantum efficiency of 3.93% and a photodetection responsivity of 1.42 A W -1 . © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Electron gas interacting in a metal, submitted to a strong magnetic field

    International Nuclear Information System (INIS)

    Alcaraz, Francisco Castilho

    1977-01-01

    Using the propagator's technique in the grand ensemble developed by Montroll and Ward we investigate the magnetic properties of an interacting electron gas in a strong magnetic field. The free propagator properly constructed shows that the spin paramagnetism does not have a term with strong temperature dependence, contrary to the result of Isihara. Considering the electron density to be constant, the dHVA oscillations in the magnetic susceptibility and sound velocity, considering the effects of first exchange interactions, show only one phase in agreement with experimental result, while Ichimura and Isihara obtained two phases differing by π/2. The effects of first order exchange interactions in the dHVA oscillations of the magnetic susceptibility and sound velocity give rise to an exponential factor in the amplitudes of oscillator (Dingle factor), being the Dingle temperature linearly dependent of the Fermi velocity. The calculations of the ring diagram contribution to the grand partition function, show that the approximation used by Isihara for this calculations is not good and the dHVA oscillations of the contributions from the ring diagrams for the grand partition function have a phase differing by π/2 from that obtained by Isihara. (author)

  8. A many-particle adiabatic invariant of strongly magnetized pure electron plasmas

    International Nuclear Information System (INIS)

    Hjorth, P.G.

    1988-01-01

    A pure electron plasma is said to be strongly magnetized if the cyclotron radius of the electrons is much smaller than the classical distance of closest approach. In this parameter regime a many-particle adiabatic invariant constrains the collisional dynamics. For the case of a uniform magnetic field, the adiabatic invariant is the total kinetic energy associated with the electron velocity components that are perpendicular to the magnetic field (i.e., Σ j mv 2 j perpendicular/2). Were the adiabatic invariant an exact constant of the motion, no exchange of energy would be possible between the parallel and the perpendicular degrees of freedom, and the plasma could develop and maintain two different temperatures T parallel and T perpendicular. An adiabatic invariant, however, is not strictly conserved. In the present case, each collision produces an exponentially small exchange of energy between the parallel and the perpendicular degrees of freedom, and these act cumulatively in such a way that T parallel and T perpendicular eventually relax to a common value. The rate of equilibrium is calculated, both in the case where the collisions are described by classical mechanics and in the case where the collisions are described by quantum mechanics, the two calculations giving essentially the same result. A molecular dynamics simulation has been carried out, verifying the existence of this unusual invariant, and verifying the theoretically predicted rate equation

  9. Physics of heavy fermions heavy fermions and strongly correlated electrons systems

    CERN Document Server

    Onuki, Yoshichika

    2018-01-01

    A large variety of materials prove to be fascinating in solid state and condensed matter physics. New materials create new physics, which is spearheaded by the international experimental expert, Prof Yoshichika Onuki. Among them, the f electrons of rare earth and actinide compounds typically exhibit a variety of characteristic properties, including spin and charge orderings, spin and valence fluctuations, heavy fermions, and anisotropic superconductivity. These are mainly manifestations of better competitive phenomena between the RKKY interaction and the Kondo effect. The present text is written so as to understand these phenomena and the research they prompt. For example, superconductivity was once regarded as one of the more well-understood many-body problems. However, it is, in fact, still an exciting phenomenon in new materials. Additionally, magnetism and superconductivity interplay strongly in heavy fermion superconductors. The understanding of anisotropic superconductivity and magnetism is a challengin...

  10. Strong Adhesion of Silver/Polypyrrole Composite onto Plastic Substrates toward Flexible Electronics

    Science.gov (United States)

    Kawakita, Jin; Hashimoto, Yasuo; Chikyow, Toyohiro

    2013-06-01

    Flexible electronics require sufficient adhesion to substrates, such as a plastic or a polymer, of the electric wiring for devices. A composite of a conducting metal and a polymer is a candidate alternative to pure metals in terms of wire flexibility. The purpose of this study was to evaluate the adhesiveness of a silver/polypyrrole composite to plastic substrates and to clarify the mechanism of adhesion. The composite was prepared on various plastic substrates by dropping its fluid dispersion. Its adhesiveness was evaluated by the peel-off test and its interfacial structure was characterized by microscopy measurements. Some polymers including Teflon with generally weak adhesion to different materials showed a high adhesiveness of more than 90%. The strong adhesion was related to the anchoring effect of the composite penetrating into the pores near the surface of the substrate.

  11. Strong-coupling electron-phonon superconductivity in H{sub 3}S

    Energy Technology Data Exchange (ETDEWEB)

    Pickett, Warren E. [University of California, Davis, CA (United States); Quan, Yundi [Beijing Normal University, Beijing (China)

    2016-07-01

    The superconducting phase of hydrogen sulfide at T{sub c} = 200 K observed by Eremets' group at pressures around 200 GPa is simple bcc Im-3m H{sub 3}S. Remarkably, this record high temperature superconductor was predicted beforehand by Duan et al., so the theory would seem to be in place. Here we will discuss why this is not true. Several extremes are involved: extreme pressure, meaning reduction of volume;extremely high H phonon energy scale around 1400 K; unusually narrow peak in the density of states at the Fermi level; extremely high temperature for a superconductor. Analysis of the H3S electronic structure and two important van Hove singularities (vHs) reveal the effect of sulfur. The implications for the strong coupling Migdal-Eliashberg theory will be discussed. Followed by comments on ways of increasing T{sub c} in H{sub 3}S-like materials.

  12. Periodic Forcing of a 555-IC Based Electronic Oscillator in the Strong Coupling Limit

    Science.gov (United States)

    Santillán, Moisés

    We designed and developed a master-slave electronic oscillatory system (based on the 555-timer IC working in the astable mode), and investigated its dynamic behavior regarding synchronization. For that purpose, we measured the rotation numbers corresponding to the phase-locking rhythms achieved in a large set of values of the normalized forcing frequency (NFF) and of the coupling strength between the master and the slave oscillators. In particular, we were interested in the system behavior in the strong-coupling limit, because such problem has not been extensively studied from an experimental perspective. Our results indicate that, in such a limit, a degenerate codimension-2 bifurcation point at NFF = 2 exists, in which all the phase-locking regions converge. These findings were corroborated by means of a mathematical model developed to that end, as well as by ad hoc further experiments.

  13. Holstein-Primakoff representation and supercoherent states for strongly correlated electron systems

    International Nuclear Information System (INIS)

    Azakov, S.

    1999-09-01

    First we show that the algebra of operators entering the Hamiltonian of the t-J model describing the strongly correlated electron system is graded spl(2.1) algebra. Then after a brief discussion of its atypical representations we construct the Holstein-Primakoff nonlinear realization of these operators which allows to carry out the systematic semiclassical approximation, similarly to the spin-wave theory of localized magnetism. The fact that the t-J model describes the itinerant magnetism is reflected in the presence of the spinless fermions. For the supersymmetric spl(2.1) algebra the supercoherent states are proposed and the partition function of the t-J model is represented as a path integral with the help of these states. (author)

  14. Directed emission of CdSe nanoplatelets originating from strongly anisotropic 2D electronic structure

    Science.gov (United States)

    Scott, Riccardo; Heckmann, Jan; Prudnikau, Anatol V.; Antanovich, Artsiom; Mikhailov, Aleksandr; Owschimikow, Nina; Artemyev, Mikhail; Climente, Juan I.; Woggon, Ulrike; Grosse, Nicolai B.; Achtstein, Alexander W.

    2017-12-01

    Intrinsically directional light emitters are potentially important for applications in photonics including lasing and energy-efficient display technology. Here, we propose a new route to overcome intrinsic efficiency limitations in light-emitting devices by studying a CdSe nanoplatelets monolayer that exhibits strongly anisotropic, directed photoluminescence. Analysis of the two-dimensional k-space distribution reveals the underlying internal transition dipole distribution. The observed directed emission is related to the anisotropy of the electronic Bloch states governing the exciton transition dipole moment and forming a bright plane. The strongly directed emission perpendicular to the platelet is further enhanced by the optical local density of states and local fields. In contrast to the emission directionality, the off-resonant absorption into the energetically higher 2D-continuum of states is isotropic. These contrasting optical properties make the oriented CdSe nanoplatelets, or superstructures of parallel-oriented platelets, an interesting and potentially useful class of semiconductor-based emitters.

  15. Evidence for strong electron-lattice coupling in La2-xSrxNiO4

    International Nuclear Information System (INIS)

    McQueeney, R.J.; Sarrao, J.L.

    1999-01-01

    The inelastic neutron scattering spectra were measured for several Sr concentrations of polycrystalline La 2-x Sr x NiO 4 . The authors find that the generalized phonon density-of-states is identical for x = 0 and x = 1/8. For x = 1/3 and x = 1/2, the band of phonons corresponding to the in-plane oxygen vibrations (> 65 meV) splits into two subbands centered at 75 meV and 85 meV. The lower frequency band increases in amplitude for the x = 1/2 sample, indicating that it is directly related to the hole concentration. These changes are associated with the coupling of oxygen vibrations to doped holes which reside in the NiO 2 planes and are a signature of strong electron-lattice coupling. Comparison of La 1.9 Sr 0.1 CuO 4 and La 1.875 Sr 0.125 NiO 4 demonstrates that much stronger electron-lattice coupling occurs for particular modes in the cuprate for modest doping and is likely related to the metallic nature of the cuprate

  16. Electron beam induced strong organic/inorganic grafting for thermally stable lithium-ion battery separators

    Science.gov (United States)

    Choi, Yunah; Kim, Jin Il; Moon, Jungjin; Jeong, Jongyeob; Park, Jong Hyeok

    2018-06-01

    A tailored interface between organic and inorganic materials is of great importance to maximize the synergistic effects from hybridization. Polyethylene separators over-coated with inorganic thin films are the state-of-the art technology for preparing various secondary batteries with high safety. Unfortunately, the organic/inorganic hybrid separators have the drawback of a non-ideal interface, thus causing poor thermal/dimensional stability. Here, we report a straightforward method to resolve the drawback of the non-ideal interface between vapor deposited SiO2 and polyethylene separators, to produce a highly stable lithium-ion battery separator through strong chemical linking generated by direct electron beam irradiation. The simple treatment with an electron beam with an optimized dose generates thermally stable polymer separators, which may enhance battery safety under high-temperature conditions. Additionally, the newly formed Si-O-C or Si-CH3 chemical bonding enhances electrolyte-separator compatibility and thus may provide a better environment for ionic transport between the cathode and anode, thereby leading to better charge/discharge behaviors.

  17. Compact X-ray sources. Simulating the electron/strong laser interaction

    Energy Technology Data Exchange (ETDEWEB)

    Hartin, Anthony [DESY, CFEL, Hamburg (Germany)

    2016-07-01

    The collision of an intense laser with an electron bunch can be used to produce X-rays via the inverse Compton scattering (ICS) mechanism. The ICS can be simulated via either a classical theory in which electrons and photons are treated in terms of classical electromagnetic waves - or a quantum theory in which charged particles interact with strong electromagnetic fields. The laser intensity used in a practical ICS collision is likely to be at such a level that quantum effects may be significant and the use of quantum theory may become a necessity. A simulation study is presented here comparing the classical and quantum approaches to the ICS. A custom particle-in-cell (PIC) software code, with photon generation by monte carlo of the exact quantum transition probability is used to simulate the quantum treatment. Peak resonant energies and the angular distribution of the X-rays are obtained and compared with those predicted by the classical theory. The conditions under which significant differences between the two theories emerges is obtained.

  18. Opiate and opioid withdrawal

    Science.gov (United States)

    ... opiate withdrawal; Oxycontin - opiate withdrawal; Hydrocodone - opiate withdrawal; Detox - opiates; Detoxification - opiates ... facilities set up to help people with detoxification (detox). In a regular hospital, if symptoms are severe. ...

  19. Exotic Quantum Phases and Phase Transitions of Strongly Interacting Electrons in Low-Dimensional Systems

    Science.gov (United States)

    Mishmash, Ryan V.

    Experiments on strongly correlated quasi-two-dimensional electronic materials---for example, the high-temperature cuprate superconductors and the putative quantum spin liquids kappa-(BEDT-TTF)2Cu2(CN)3 and EtMe3Sb[Pd(dmit)2]2---routinely reveal highly mysterious quantum behavior which cannot be explained in terms of weakly interacting degrees of freedom. Theoretical progress thus requires the introduction of completely new concepts and machinery beyond the traditional framework of the band theory of solids and its interacting counterpart, Landau's Fermi liquid theory. In full two dimensions, controlled and reliable analytical approaches to such problems are severely lacking, as are numerical simulations of even the simplest of model Hamiltonians due to the infamous fermionic sign problem. Here, we attempt to circumvent some of these difficulties by studying analogous problems in quasi-one dimension. In this lower dimensional setting, theoretical and numerical tractability are on much stronger footing due to the methods of bosonization and the density matrix renormalization group, respectively. Using these techniques, we attack two problems: (1) the Mott transition between a Fermi liquid metal and a quantum spin liquid as potentially directly relevant to the organic compounds kappa-(BEDT-TTF)2Cu 2(CN)3 and EtMe3Sb[Pd(dmit)2] 2 and (2) non-Fermi liquid metals as strongly motivated by the strange metal phase observed in the cuprates. In both cases, we are able to realize highly exotic quantum phases as ground states of reasonable microscopic models. This lends strong credence to respective underlying slave-particle descriptions of the low-energy physics, which are inherently strongly interacting and also unconventional in comparison to weakly interacting alternatives. Finally, working in two dimensions directly, we propose a new slave-particle theory which explains in a universal way many of the intriguing experimental results of the triangular lattice organic spin

  20. Local Magnetism in Strongly Correlated Electron Systems with Orbital Degrees of Freedom

    Science.gov (United States)

    Ducatman, Samuel Charles

    The central aim of my research is to explain the connection between the macroscopic behavior and the microscopic physics of strongly correlated electron systems with orbital degrees of freedom through the use of effective models. My dissertation focuses on the sub-class of these materials where electrons appear to be localized by interactions, and magnetic ions have well measured magnetic moments. This suggests that we can capture the low-energy physics of the material by employing a minimal model featuring localized spins which interact with each other through exchange couplings. I describe Fe1+y Te and beta-Li2IrO3 with effective models primarily focusing on the spins of the magnetic ions, in this case Fe and Ir, respectively. The goal with both materials is to gain insight and make predictions for experimentalists. In chapter 2, I focus on Fe1+yTe. I describe why we believe the magnetic ground state of this material, with an observed Bragg peak at Q +/- pi/2, pi/2), can be described by a Heisenberg model with 1st, 2nd, and 3rd neighbor interactions. I present two possible ground states of this model in the small J1 limit, the bicollinear and plaquette states. In order to predict which ground state the model prefers, I calculate the spin wave spectrum with 1/S corrections, and I find the model naturally selects the "plaquette state." I give a brief description of the ways this result could be tested using experimental techniques such as polarized neutron scattering. In chapter 3, I extend the model used in chapter 2. This is necessary because the Heisenberg model we employed cannot explain why Fe1+yTe undergoes a phase transition as y is increased. We add an additional elements to our calculation; we assume that electrons in some of the Fe 3D orbitals have selectively localized while others remain itinerant. We write a new Hamiltonian, where localized moments acquire a new long-range RKKY-like interaction from interactions with the itinerant electrons. We are

  1. Quantum Monte Carlo methods and strongly correlated electrons on honeycomb structures

    Energy Technology Data Exchange (ETDEWEB)

    Lang, Thomas C.

    2010-12-16

    In this thesis we apply recently developed, as well as sophisticated quantum Monte Carlo methods to numerically investigate models of strongly correlated electron systems on honeycomb structures. The latter are of particular interest owing to their unique properties when simulating electrons on them, like the relativistic dispersion, strong quantum fluctuations and their resistance against instabilities. This work covers several projects including the advancement of the weak-coupling continuous time quantum Monte Carlo and its application to zero temperature and phonons, quantum phase transitions of valence bond solids in spin-1/2 Heisenberg systems using projector quantum Monte Carlo in the valence bond basis, and the magnetic field induced transition to a canted antiferromagnet of the Hubbard model on the honeycomb lattice. The emphasis lies on two projects investigating the phase diagram of the SU(2) and the SU(N)-symmetric Hubbard model on the hexagonal lattice. At sufficiently low temperatures, condensed-matter systems tend to develop order. An exception are quantum spin-liquids, where fluctuations prevent a transition to an ordered state down to the lowest temperatures. Previously elusive in experimentally relevant microscopic two-dimensional models, we show by means of large-scale quantum Monte Carlo simulations of the SU(2) Hubbard model on the honeycomb lattice, that a quantum spin-liquid emerges between the state described by massless Dirac fermions and an antiferromagnetically ordered Mott insulator. This unexpected quantum-disordered state is found to be a short-range resonating valence bond liquid, akin to the one proposed for high temperature superconductors. Inspired by the rich phase diagrams of SU(N) models we study the SU(N)-symmetric Hubbard Heisenberg quantum antiferromagnet on the honeycomb lattice to investigate the reliability of 1/N corrections to large-N results by means of numerically exact QMC simulations. We study the melting of phases

  2. Solution of the Eliashberg equations for a very strong electron-phonon coupling with a low-energy cutoff

    International Nuclear Information System (INIS)

    Weger, M.; Barbiellini, B.; Jarlborg, T.; Peter, M.; Santi, G.

    1995-01-01

    We solve the Eliashberg equations for the case of an explicit vector k dependence of the interactions, and of the resulting self-energies Σ 1 ( vector k,ω), Σ 2 ( vector k,ω). We consider a strong energy-dependence of the electron-electron scattering-rate τ ee -1 , which is associated with a strong energy-dependence of the electron-phonon matrix element g(k,k'). We characterize this energy-dependence by a cutoff ξ 1 , which is of the order of the phonon frequency ω ph . We find that we can account for a large number of unexpected features of the superconductivity of the cuprates by the BCS electron-phonon theory, if we consider very large values of the McMillan coupling constant λ ph , and small values of the cutoff ξ 1 . Specifically, the Coulomb interaction is found not to depress T c ; the isotope effect is strongly reduced when ξ 1 ph . We find solutions in which the gap function Δ( vector k,ω) has extended s-wave symmetry but is very anisotropic. We suggest that the underlying cause of the strong energy-dependence is a very small electronic screening parameter at the Fermi surface; the electron-phonon matrix element g is abnormally large, and this accounts for the high transition temperatures of the cuprates. An order of magnitude estimate suggests that the electron-phonon mechanism can account for transition temperatures up to about 200 K. We thus propose a very-strong-coupling theory, in which the renormalization functions, in particular the energy-renormalization X, depend very strongly on the superconducting gap Δ, and thus display a very strong temperature-dependence between T c and T=0. An experimental manifestation of the very strong coupling with a small cutoff is a zero bias anomaly sometimes observed in tunneling experiments. (orig.)

  3. Full-gap superconductivity with strong electron correlations in the β-pyrochlore KOs2O6

    International Nuclear Information System (INIS)

    Kasahara, Y.; Shimono, Y.; Kato, T.; Hashimoto, K.; Shibauchi, T.; Matsuda, Y.; Yonezawa, S.; Muraoka, Y.; Yamaura, J.; Nagao, Y.; Hiroi, Z.

    2008-01-01

    To elucidate the superconducting gap structure and the influence of rattling motion on quasiparticle dynamics in the superconducting state of KOs 2 O 6 , the thermal conductivity and microwave surface impedance were measured at low temperatures. The magnetic field dependence of thermal conductivity and temperature dependence of penetration depth demonstrate full-gap superconductivity in KOs 2 O 6 . The quasiparticle scattering time is strongly enhanced in the superconducting state, indicating a strong electron inelastic scattering in the normal state. These results highlight that KOs 2 O 6 is unique among superconductors with strong electron correlations

  4. Phase separation in strongly correlated electron systems with two types of charge carriers

    International Nuclear Information System (INIS)

    Kugel, K.I.; Rakhmanov, A.L.; Sboychakov, A.O.

    2007-01-01

    Full text: A competition between the localization of the charge carriers due to Jahn-Teller distortions and the energy gain due to their delocalization in doped manganite and related magnetic oxides is analyzed based on a Kondo-lattice type model. The resulting effective Hamiltonian is, in fact, a generalization of the Falicov-Kimball model. We find that the number of itinerant charge carriers can be significantly lower than that implied by the doping level x. The phase diagram of the model in the T plane is constructed. The system exhibits magnetic ordered (antiferromagnetic, ferromagnetic, or canted) states as well the paramagnetic states with zero and nonzero density of the itinerant electrons. It is shown that a phase-separation is favorable in energy for a wide doping range. The characteristic size of inhomogeneities in a phase-separated state is of the order of several lattice constants. We also analyzed the two-band Hubbard model in the limit of strong on-site Coulomb repulsion. It was shown that such a system has a tendency to phase separation into the regions with different charge densities even in the absence of magnetic or any other ordering, if the ratio of the bandwidths is large enough. The work was supported by the European project CoMePhS and by the Russian Foundation for Basic Research, project no. 05-02-17600. (authors)

  5. Finite-Temperature Variational Monte Carlo Method for Strongly Correlated Electron Systems

    Science.gov (United States)

    Takai, Kensaku; Ido, Kota; Misawa, Takahiro; Yamaji, Youhei; Imada, Masatoshi

    2016-03-01

    A new computational method for finite-temperature properties of strongly correlated electrons is proposed by extending the variational Monte Carlo method originally developed for the ground state. The method is based on the path integral in the imaginary-time formulation, starting from the infinite-temperature state that is well approximated by a small number of certain random initial states. Lower temperatures are progressively reached by the imaginary-time evolution. The algorithm follows the framework of the quantum transfer matrix and finite-temperature Lanczos methods, but we extend them to treat much larger system sizes without the negative sign problem by optimizing the truncated Hilbert space on the basis of the time-dependent variational principle (TDVP). This optimization algorithm is equivalent to the stochastic reconfiguration (SR) method that has been frequently used for the ground state to optimally truncate the Hilbert space. The obtained finite-temperature states allow an interpretation based on the thermal pure quantum (TPQ) state instead of the conventional canonical-ensemble average. Our method is tested for the one- and two-dimensional Hubbard models and its accuracy and efficiency are demonstrated.

  6. Strong-Field Modulated Diffraction Effects in the Correlated Electron-Nuclear Motion in Dissociating H2+

    International Nuclear Information System (INIS)

    He Feng; Becker, Andreas; Thumm, Uwe

    2008-01-01

    We show that the electronic dynamics in a molecule driven by a strong field is complex and potentially even counterintuitive. As a prototype example, we simulate the interaction of a dissociating H 2 + molecule with an intense infrared laser pulse. Depending on the laser intensity, the direction of the electron's motion between the two nuclei is found to follow or oppose the classical laser-electric force. We explain the sensitive dependence of the correlated electronic-nuclear motion in terms of the diffracting electronic momentum distribution of the dissociating two-center system. The distribution is dynamically modulated by the nuclear motion and periodically shifted in the oscillating infrared electric field

  7. Electronic zero-point oscillations in the strong-interaction limit of density functional theory

    NARCIS (Netherlands)

    Gori Giorgi, P.; Vignale, G.; Seidl, M.

    2009-01-01

    The exchange-correlation energy in Kohn-Sham density functional theory can be expressed exactly in terms of the change in the expectation of the electron-electron repulsion operator when, in the many-electron Hamiltonian, this same operator is multiplied by a real parameter λ varying between 0

  8. 75 FR 7526 - Withdrawal of Regulatory Guide

    Science.gov (United States)

    2010-02-19

    ...'s Electronic Reading Room at http://www.nrc.gov/reading-rm/doc-collections . Regulatory guides are... NUCLEAR REGULATORY COMMISSION [NRC-2010-0052] Withdrawal of Regulatory Guide AGENCY: Nuclear Regulatory Commission. ACTION: Withdrawal of Regulatory Guide 1.56, ``Maintenance of Water Purity in Boiling...

  9. Fifty years old, and still going strong: Transmission electron optical studies of materials

    International Nuclear Information System (INIS)

    Brown, L.M.

    2008-01-01

    Highlights in the history of transmission electron microscopy and scanning transmission electron microscopy include the introduction of diffraction contrast, resolution of periodic lattices by phase contrast and incoherent imaging via the high-angle annular dark-field detector. Convergent-beam electron diffraction and analytical electron microscopy, especially the application of energy-dispersive X-ray and electron energy-loss spectrometry, have provided structural and chemical information in addition to strain contrast from lattice defects. From the outset, novel specimen stages and improvements to aid the operator enhanced the electron-optical engineering provided by the instrument makers. The spatial resolution achieved was mainly determined by the way the instrument was used, and not by the basic resolution limit set by the electron optics. However, the application of computer controlled correction of spherical (and higher order) aberration has resulted in a new generation of instruments capable of sub-Angstrom point-to-point resolution. This improved performance, combined with electron energy-loss spectrometry, promises genuine three-dimensional determination of atomic and electronic structure: an indispensable weapon in the battle to fabricate and control useful nanostructures. The uncertainty principle now fundamentally restricts some of the observations one can make, but much more technical development over the next decades must occur before one can say that the techniques of electron-optical imaging of material structure have reached their fundamental limitations. One can expect remarkable progress over the next few years

  10. Dynamical instability, strong anharmonicity and electron-phonon coupling in KOs2O6: First-principles calculations

    Science.gov (United States)

    Wang, Wei; Sun, Jiafa; Li, Bin; He, Junqi

    2017-09-01

    First-principles pseudopotential calculations on phonon and electronic properties of β -pyrochlore superconductor KOs2O6 are performed. The imaginary soft-phonon modes with a special double-well potential for the lowest Eu(1) mode and the second lowest T1u(1) mode are reported, which indicates the dynamical instability in KOs2O6. However, the double wells are too small to induce a structural phase transformation in KOs2O6. The strong anharmonicity especially for K T2g(1) phonon mode is got, which is approved to be from the strong electron-phonon coupling that supports the superconductivity in KOs2O6.

  11. PREFACE: International Conference on Strongly Correlated Electron Systems 2014 (SCES2014)

    Science.gov (United States)

    2015-03-01

    The 2014 International Conference on Strongly Correlated Electron Systems (SCES) was held in Grenoble from the 7th to 11th of July on the campus of the University of Grenoble. It was a great privilege to have the conference in Grenoble after the series of meetings in Sendai (1992), San Diego (1993), Amsterdam (1994), Goa (1995), Zürich (1996), Paris (1998), Nagano (1999), Ann Arbor (2001), Krakow (2002), Karlsruhe (2004), Vienna (2005), Houston (2007), Buzios (2008), Santa Fe (2010), Cambridge (2011) and Tokyo (2013). Every three years, SCES joins the triennial conference on magnetism ICM. In 2015, ICM will take place in Barcelona. The meeting gathered an audience of 875 participants who actively interacted inside and outside of conference rooms. A large number of posters (530) was balanced with four parallel oral sessions which included 86 invited speakers and 141 short oral contributions. A useful arrangement was the possibility to put poster presentations on the website so participants could see them all through the conference week. Each morning two plenary sessions were held, ending on Friday with experimental and theoretical summaries delivered by Philipp Gegenwart (Augsburg) and Andrew Millis (Columbia). The plenary sessions were given by Gabriel Kotliar (Rutgers), Masashi Kawasaki (Tokyo), Jennifer Hoffman (Harvard), Mathias Vojta (Dresden), Ashvin Vishwanath (Berkeley), Andrea Cavalleri (Hamburg), Marc-Henri Julien (Grenoble), Neil Mathur (Cambridge), Giniyat Khaliullin (Stuttgart), and Toshiro Sakakibara (Tokyo). The parallel oral sessions were prepared by 40 symposium organizers selected by the chairman (Antoine Georges) and co-chairman (Kamran Behnia) of the Program Committee with the supplementary rule that speakers had not delivered an invited talk at the previous SCES conference held in 2013 in Tokyo. Special attention was given to help young researchers via grants to 40 overseas students. Perhaps due to the additional possibility of cheap

  12. On the acceleration of charged particles by strong longitudinal plasma wake fields excited by electron bunches

    International Nuclear Information System (INIS)

    Amatuni, A.Ts.; Elbakyan, S.S.; Sekhpossyan, E.V.

    1985-01-01

    The possibility of the use of longitudinal field excited in a plasma by electron bunches to accelerate charged particles is investigated. It is shown that the highets value of accelerating fields proportional to the square root of factor of electrons in the bunch is achieved in the case when bunch particle density approaches a limit equal to the half of the the plasma electron equilibrium density

  13. Rapid plasma heating by collective interactions, using strong turbulence and relativistic electron beams

    International Nuclear Information System (INIS)

    Wharton, C.B.

    1977-01-01

    A multi-kilovolt, moderate density plasma was generated in a magnetic mirror confinement system by two methods: turbulent heating and relativistic electron beam. Extensive diagnostic development permitted the measurement of important plasma characteristics, leading to interesting and novel conclusions regarding heating and loss mechanisms. Electron and ion heating mechanisms were categorized, and parameter studies made to establish ranges of importance. Nonthermal ion and electron energy distributions were measured. Beam propagation and energy deposition studies yielded the spatial dependence of plasma heating

  14. Effect of density distribution of cathode emission on the flux character in a strong-current electron gun

    International Nuclear Information System (INIS)

    Matora, I.M.; Merkulov, L.A.

    1975-01-01

    The effect is considered of two kinds of a dependence of the emission density from the electric field voltage on the emitter surface of a strong-current electron gun (the Schottky law and the ''3/2'' law) upon the choice of a form for the meridional cross section of this emitter at the condition of electron flux laminarity. A calculation example is given for electron gun with close to laminar flow assuming the validity of the Schottky law. The results of calculation of varying the laminar flux character are given which appears when varying parameters of the gun at the voltage 500 kV and current 250 A

  15. Delayed electron emission in strong-field driven tunnelling from a metallic nanotip in the multi-electron regime

    Science.gov (United States)

    Yanagisawa, Hirofumi; Schnepp, Sascha; Hafner, Christian; Hengsberger, Matthias; Kim, Dong Eon; Kling, Matthias F.; Landsman, Alexandra; Gallmann, Lukas; Osterwalder, Jürg

    2016-01-01

    Illuminating a nano-sized metallic tip with ultrashort laser pulses leads to the emission of electrons due to multiphoton excitations. As optical fields become stronger, tunnelling emission directly from the Fermi level becomes prevalent. This can generate coherent electron waves in vacuum leading to a variety of attosecond phenomena. Working at high emission currents where multi-electron effects are significant, we were able to characterize the transition from one regime to the other. Specifically, we found that the onset of laser-driven tunnelling emission is heralded by the appearance of a peculiar delayed emission channel. In this channel, the electrons emitted via laser-driven tunnelling emission are driven back into the metal, and some of the electrons reappear in the vacuum with some delay time after undergoing inelastic scattering and cascading processes inside the metal. Our understanding of these processes gives insights on attosecond tunnelling emission from solids and should prove useful in designing new types of pulsed electron sources. PMID:27786287

  16. Electron Fluid Description of Wave-Particle Interactions in Strong Buneman Turbulence

    Science.gov (United States)

    Che, Haihong

    2013-10-01

    To understand the nature of anomalous resistivity in magnetic reconnection, we investigate turbulence-induced momentum transport and energy dissipation associated with electron heating in Buneman instability. Using 3D particle-in-cell simulations, we find that the macroscopic effects generated by wave-particle interactions can be described by a set of electron fluid equations. These equations show that the energy dissipation and momentum transports in Buneman instability are locally quasi-static but globally non-static and irreversible. Turbulence drag dissipates both the bulk energy of electron streams and the associated magnetic energy. The decrease of magnetic field maintains an inductive electric field that re-accelerates electrons. The net loss of streaming energy is converted into electron heat and increases the electron Boltzmann entropy. The growth of self-sustained Buneman waves satisfies a Bernoulli-like equation which relates the turbulence-induced convective momentum transport and thermal momentum transport. Electron trapping and de-trapping drives local momentum transports, while phase mixing converts convective momentum into thermal momentum.These two local momentum transports sustain the Buneman waves and act as the micro-macro link in the anomalous heating process. This research is supported by the NASA Postdoctoral Program at NASA/GSFC administered by Oak Ridge Associated Universities through a contract with NASA.

  17. Heating of a plasma by a powerful relativistic electron beam in a strong magnetic field

    International Nuclear Information System (INIS)

    Arzhannikov, A.V.; Brejzman, B.N.; Vyacheslavov, L.N.; Kojdan, V.S.; Konyukhov, V.V.; Ryutov, D.D.

    1975-01-01

    The results of an experimental investigation into the interaction of a powerful relativistic electron beam with plasma in the INAR apparatus are presented. The relativistic electron beam had initial energy of 1 MeV, maximum injection current of 10 kA, duration of 70 ns, and diameter of 2 cm. The total beam energy at entry into the plasma was approximately 300 J. The beam was injected into the column of a hydrogen plasma 230 cm long, 8 cm in diameter, and with a density of 3x10 14 cm -3 . The magnetic field had mirror-trap geometry (mirror ratio 1.7, intensity in the uniform region up to 15 kOe). In the experiments various diagnostic methods were used, making it possible to measure the beam current, the total current within the plasma, the total energy of the beam entering and leaving the plasma, and the distribution of beam current over the cross-section at the plasma outlet; the energy content of the plasma was determined from diamagnetic measurements; the electron distribution function was analysed by the method of Thomson scattering of light at 90 0 . From an analysis of the shape of the diamagnetic signals and distribution of diamagnetism along the length of the apparatus it was established that under the assumption of predominant electron heating, the temperature of plasma electrons in order of magnitude equals 1 keV for a plasma density of 5x10 13 cm -3 . The cause of heating cannot be dissipation of the reversed current. Thomson scattering of laser radiation indicated the presence of a comparatively cold plasma component with a temperature of 25 eV. High-energy electrons moving from the opposite direction toward the beam were recorded; their appearance evidently was associated with acceleration of plasma electrons in the induction fields. Mechanisms which can provide effective heating of the whole mass of electrons under conditions in which pair collisions are minor are indicated. (author)

  18. Nuclear excitation via the motion of electrons in a strong laser field

    International Nuclear Information System (INIS)

    Berger, J.F.; Gogny, D.; Weiss, M.S.

    1987-12-01

    A method of switching from a nuclear isomeric state to a lasing state is examined. A semi-classical model of laser-electron-nuclear coupling is developed. In it the electrons are treated as free in the external field of the laser, but with initial conditions corresponding to their atomic orbits. Application is made to testing this model in 235 U and to the design criteria of a gamma-ray laser. 14 refs., 2 tabs

  19. Heating of a plasma by a powerful relativistic electron beam in a strong magnetic field

    International Nuclear Information System (INIS)

    Arzhannikov, A.V.; Brejzman, B.N.; Vyacheslavov, L.N.; Kojdan, V.S.; Konyukhov, V.V.; Ryutov, D.D.

    1975-01-01

    The results of an experimental investigation into the interaction of a powerful relativistic electron beam with plasma in the INAR apparatus are presented. The relativistic electron beam had initial energy of 1 MeV, maximum injection current of 10 kA, duration of 70 ns, and diameter of 2 cm. The total beam energy at entry into the plasma was approximately 300 J. The beam was injected into the column of a hydrogen plasma 230 cm long, 8 cm in diameter, and with a density of 3 x 10 14 cm -3 . The magnetic field had mirror-trap geometry (mirror ratio 1.7, intensity in the uniform portion up to 15 kOe). In the experiments, various diagnostic methods were used, making it possible to measure the beam current, the total current within the plasma, the total energy of the beam entering and leaving the plasma, and the distribution of beam current over the cross-section at the plasma outlet; opposing high-energy electrons were recorded. The density of the preliminary plasma was controlled during the experiment; the energy content of the plasma was determined from diamagnetic measurements; the electron distribution function was analysed by the method of Thomson scattering of light at 90deg. From an analysis of the shape of the diamagnetic signals and distribution of diamagnetism along the length of the apparatus it was established that under the assumption of predominant electron heating, the temperature of plasma electrons in order of magnitude equals 1 keV for a plasma density of 5 x 10 13 cm -3 . The cause of heating cannot be dissipation of the reversed current. According to Thomson scattering of laser radiation, the authors established the presence of a comparatively cold plasma component with temperature of 25 eV. High-energy electrons moving from the opposite direction toward the beam were recorded; their appearance evidently was associated with acceleration of plasma electrons in the induction fields. Mechanisms which can provide effective heating of the whole mass of

  20. Observation of strong reflection of electron waves exiting a ballistic channel at low energy

    Energy Technology Data Exchange (ETDEWEB)

    Vaz, Canute I.; Campbell, Jason P.; Ryan, Jason T.; Gundlach, David; Cheung, Kin. P., E-mail: Kin.Cheung@NIST.gov [National Institute of Standards and Technology, Gaithersburg, MD 20899-8120 (United States); Liu, Changze [National Institute of Standards and Technology, Gaithersburg, MD 20899-8120 (United States); Institute of Microelectronics, Peking University, Beijing 100871 (China); Southwick, Richard G. [National Institute of Standards and Technology, Gaithersburg, MD 20899-8120 (United States); IBM Research, Albany, NY 12205 (United States); Oates, Anthony S. [Taiwan Semiconductor Manufacturing Corporation, Hsinchu 30844, Taiwan (China); Huang, Ru [Institute of Microelectronics, Peking University, Beijing 100871 (China)

    2016-06-15

    Wave scattering by a potential step is a ubiquitous concept. Thus, it is surprising that theoretical treatments of ballistic transport in nanoscale devices, from quantum point contacts to ballistic transistors, assume no reflection even when the potential step is encountered upon exiting the device. Experiments so far seem to support this even if it is not clear why. Here we report clear evidence of coherent reflection when electron wave exits the channel of a nanoscale transistor and when the electron energy is low. The observed behavior is well described by a simple rectangular potential barrier model which the Schrodinger’s equation can be solved exactly. We can explain why reflection is not observed in most situations but cannot be ignored in some important situations. Our experiment also represents a direct measurement of electron injection velocity - a critical quantity in nanoscale transistors that is widely considered not measurable.

  1. Ionization of a two-electron atom in a strong electromagnetic field

    International Nuclear Information System (INIS)

    Ovodova, O.V.; Popov, A.M.; Tikhonova, O.V.

    1997-01-01

    A one-dimensional model of a helium atom in an intense field of a femtosecond electromagnetic pulse has been constructed using the Hartree technique. 'Exact' calculations have been compared to the approximations of 'frozen' and 'passive' electrons. A nonmonotonic dependence of the single-electron ionization probability on the radiation intensity has been detected. Minima in the ionization probability are due to multiphoton resonances between different atomic states due to the dynamic Stark effect. We suggest that the ionization suppression is due to the interference stabilization in this case

  2. Magnetic-Field Control Of Tunnel-Coupling In Strongly Confined One-Dimensional Electron Systems

    Science.gov (United States)

    Fischer, S. F.; Apetrii, G.; Kunze, U.; Schuh, D.; Abstreiter, G.

    2007-04-01

    One-dimensional (1D) ballistic electron transport is studied through stacked 1D quantum conductors separated by a thin tunneling barrier. The 1D electron systems of large 1D subband spacings (more than 10 meV) allow single mode operation. Degeneracies of 1D subbands of equal lateral mode index are lifted by the formation of symmetric and antisymmetric states and are depicted by anti-crossings of transconductance maxima. We observe a mode-dependent turnover from level anti-crossings to crossings in longitudinal magnetic fields.

  3. Strain-Induced Enhancement of the Electron Energy Relaxation in Strongly Correlated Superconductors

    Directory of Open Access Journals (Sweden)

    C. Gadermaier

    2014-03-01

    Full Text Available We use femtosecond optical spectroscopy to systematically measure the primary energy relaxation rate Γ_{1} of photoexcited carriers in cuprate and pnictide superconductors. We find that Γ_{1} increases monotonically with increased negative strain in the crystallographic a axis. Generally, the Bardeen-Shockley deformation potential theorem and, specifically, pressure-induced Raman shifts reported in the literature suggest that increased negative strain enhances electron-phonon coupling, which implies that the observed direct correspondence between a and Γ_{1} is consistent with the canonical assignment of Γ_{1} to the electron-phonon interaction. The well-known nonmonotonic dependence of the superconducting critical temperature T_{c} on the a-axis strain is also reflected in a systematic dependence T_{c} on Γ_{1}, with a distinct maximum at intermediate values (∼16  ps^{−1} at room temperature. The empirical nonmonotonic systematic variation of T_{c} with the strength of the electron-phonon interaction provides us with unique insight into the role of electron-phonon interaction in relation to the mechanism of high-T_{c} superconductivity as a crossover phenomenon.

  4. The strong thermoelectric effect in nanocarbon generated by the ballistic phonon drag of electrons

    International Nuclear Information System (INIS)

    Eidelman, E D; Vul', A Ya

    2007-01-01

    The thermoelectric power and thermoelectric figure of merit for carbon nanostructure consisting of graphite-like (sp 2 ) and diamond-like (sp 3 ) regions have been investigated. The probability of electron collisions with quasi-ballistic phonons in sp 2 regions has been analysed for the first time. We have shown that the probability is not small. We have analysed the influence of various factors on the process of the electron-ballistic phonon drag (the phonon drag effect). The thermoelectric power and thermoelectric figure of merit under conditions of ballistic transport were found to be substantially higher than those in the cases of drag by thermalized phonons and of electron diffusion. The thermoelectric figure of merit (ZT) in the case of a ballistic phonon contribution to the phonon drag of electrons should be 50 times that for chaotic phonons and 500 times that in the case of the diffusion process. In that case ZT should be a record (ZT≥2-3)

  5. Strong electron dissipation by a mode converted ion hybrid (Bernstein) wave

    International Nuclear Information System (INIS)

    Lashmore-Davies, C.N.; Ram, A.K.

    1996-01-01

    The fast wave approximation, extended to include the effects of electron dissipation, is used to calculate the power mode converted to the ion hybrid (Bernstein) wave in the vicinity of the ion hybrid resonance. The power absorbed from the fast wave by ion cyclotron damping and by electron Landau and transit time damping (including cross terms) is also calculated. The fast wave equation is solved for either the Budden configuration of a cut-off-resonance pair or the triplet configuration of cut-off-resonance-cut-off. The fraction mode converted is compared for the triplet case and the Budden multi-pass situation. The electron damping rate of the ion hybrid wave is obtained from the local dispersion relation and a ray tracing code is used to calculate the damping of the mode converted ion hybrid wave by the electrons as it propagates away from the resonance. Quantitative results for a range of conditions relevant to JET, TFTR and ITER are given. copyright 1996 American Institute of Physics

  6. Afghanistan after NATO Withdrawal

    Directory of Open Access Journals (Sweden)

    Bojor Laviniu

    2015-06-01

    Full Text Available The conclusion of a conflict, called by some American analysts as “America’s Longest War”, after the withdrawal of the majority of NATO military forces, requires a careful analysis of the conditions and security environment that ISAF mission, International Security Afghan Forces, leaves as legacy to the Afghan military forces. The transfer of authority towards a strong government, recognized by most Afghan provinces, and benefiting from the support of national military forces able to cope with terrorist and insurgent threats on its own, are the minimum and necessary conditions leading the country towards a stable and secure environment and towards a sustainable development. Given these realities, any approach on the consequences of the transition towards self-sustainable governance becomes interesting and timely for any military political study. These are the prospects that we propose in our paper.

  7. Probing strong-field electron-nuclear dynamics of polyatomic molecules using proton motion

    International Nuclear Information System (INIS)

    Markevitch, Alexei N.; Smith, Stanley M.; Levis, Robert J.; Romanov, Dmitri A.

    2007-01-01

    Proton ejection during Coulomb explosion is studied for several structure-related organic molecules (anthracene, anthraquinone, and octahydroanthracene) subjected to 800 nm, 60 fs laser pulses at intensities from 0.50 to 4.0x10 14 W cm -2 . The proton kinetic energy distributions are found to be markedly structure specific. The distributions are bimodal for anthracene and octahydroanthracene and trimodal for anthraquinone. Maximum (cutoff) energies of the distributions range from 50 eV for anthracene to 83 eV for anthraquinone. The low-energy mode (∼10 eV) is most pronounced in octahydroanthracene. The dependence of the characteristic features of the distributions on the laser intensity provides insights into molecular specificity of such strong-field phenomena as (i) nonadiabatic charge localization and (ii) field-mediated restructuring of polyatomic molecules polarized by a strong laser field

  8. Simulating evaporation of surface atoms of thorium-alloyed tungsten in strong electronic fields

    International Nuclear Information System (INIS)

    Bochkanov, P.V.; Mordyuk, V.S.; Ivanov, Yu.I.

    1984-01-01

    By the Monte Carlo method simulating evaporation of surface atoms of thorium - alloyed tungsten in strong electric fields is realized. The strongest evaporation of surface atoms of pure tungsten as compared with thorium-alloyed tungsten in the contentration range of thorium atoms in tungsten matrix (1.5-15%) is shown. The evaporation rate increases with thorium atoms concentration. Determined is in relative units the surface atoms evaporation rate depending on surface temperature and electric field stront

  9. Strong electron-phonon interaction in the high-Tc superconductors: Evidence from the infrared

    International Nuclear Information System (INIS)

    Timusk, T.; Porter, C.D.; Tanner, D.B.

    1991-01-01

    We show that low-frequency structure in the infrared reflectance of the high-temperature superconductor YBa 2 Cu 3 O 7 results from the electron-phonon interaction. Characteristic antiresonant line shapes are seen in the phonon region of the spectrum and the frequency-dependent scattering rate of the mid-infrared electronic continuum has peaks at 150 cm -1 (19 meV) and at 360 cm -1 (45 meV) in good agreement with phonon density-of-states peaks in neutron time-of-flight spectra that develop in superconducting samples. The interaction between the phonons and the charge carriers can be understood in terms of a charged-phonon model

  10. High-temperature electron-hole superfluidity with strong anisotropic gaps in double phosphorene monolayers

    Science.gov (United States)

    Saberi-Pouya, S.; Zarenia, M.; Perali, A.; Vazifehshenas, T.; Peeters, F. M.

    2018-05-01

    Excitonic superfluidity in double phosphorene monolayers is investigated using the BCS mean-field equations. Highly anisotropic superfluidity is predicted where we found that the maximum superfluid gap is in the Bose-Einstein condensate (BEC) regime along the armchair direction and in the BCS-BEC crossover regime along the zigzag direction. We estimate the highest Kosterlitz-Thouless transition temperature with maximum value up to ˜90 K with onset carrier densities as high as 4 ×1012cm-2 . This transition temperature is significantly larger than what is found in double electron-hole few-layers graphene. Our results can guide experimental research toward the realization of anisotropic condensate states in electron-hole phosphorene monolayers.

  11. Magnetoresistance calculations for a two-dimensional electron gas with unilateral short-period strong modulation

    Czech Academy of Sciences Publication Activity Database

    Výborný, Karel; Smrčka, Ludvík

    2002-01-01

    Roč. 66, č. 20 (2002), s. 205318-1 - 205318-8 ISSN 0163-1829 R&D Projects: GA ČR GA202/01/0754 Institutional research plan: CEZ:AV0Z1010914 Keywords : magnetoresistance * short-period superlattices * two-dimensional electron gas Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.327, year: 2002

  12. Quantum screening effects on the electron-ion occurrence scattering time advance in strongly coupled semiclassical plasmas

    International Nuclear Information System (INIS)

    Song, Mi-Young; Jung, Young-Dae

    2003-01-01

    Quantum screening effects on the occurrence scattering time advance for elastic electron-ion collisions in strongly coupled semiclassical plasmas are investigated using the second-order eikonal analysis. The electron-ion interaction in strongly coupled semiclassical plasmas is obtained by the pseudopotential model taking into account the plasma screening and quantum effects. It is found that the quantum-mechanical effects significantly reduce the occurrence scattering time advance. It is also found that the occurrence scattering time advance increases with increasing Debye length. It is quite interesting to note that the domain of the maximum occurrence time advance is localized for the forward scattering case. The region of the scaled thermal de Broglie wave length (λ-bar) for the maximum occurrence time advance is found to be 0.4≤λ-bar≤1.4

  13. Systematics of strong nuclear amplification of gluon saturation from exclusive vector meson production in high energy electron-nucleus collisions

    Science.gov (United States)

    Mäntysaari, Heikki; Venugopalan, Raju

    2018-06-01

    We show that gluon saturation gives rise to a strong modification of the scaling in both the nuclear mass number A and the virtuality Q2 of the vector meson production cross-section in exclusive deep-inelastic scattering off nuclei. We present qualitative analytic expressions for how the scaling exponents are modified as well as quantitative predictions that can be tested at an Electron-Ion Collider.

  14. Exact time-dependent exchange-correlation potentials for strong-field electron dynamics

    International Nuclear Information System (INIS)

    Lein, Manfred; Kuemmel, Stephan

    2005-01-01

    By solving the time-dependent Schroedinger equation and inverting the time-dependent Kohn-Sham scheme we obtain the exact time-dependent exchange-correlation potential of density-functional theory for the strong-field dynamics of a correlated system. We demonstrate that essential features of the exact exchange-correlation potential can be related to derivative discontinuities in stationary density-functional theory. Incorporating the discontinuity in a time-dependent density-functional calculation greatly improves the description of the ionization process

  15. Polarization of electron-positron vacuum by strong magnetic field in theory with fundamental mass

    International Nuclear Information System (INIS)

    Kadyshevskij, V.G.; ); Rodionov, V.N.

    2003-01-01

    The exact Lagrangian function of the intensive constant magnetic field, replacing the Heisenberg-Euler Lagrangian in the traditional quantum electrodynamics, is calculated within the frames of the theory with the fundamental mass in the single-loop approximation. It is established that the obtained generalization of the Lagrangian function is substantial by arbitrary values of the magnetic field. The calculated Lagrangian in the weak field coincides with the known Heisenberg-Euler formula. The Lagrangian dependence on the field in the extremely strong fields completely disappears and it tends in this area to the threshold value, which is determined by the fundamental and lepton mass ratio [ru

  16. Strong overtones modes in inelastic electron tunneling spectroscopy with cross-conjugated molecules

    DEFF Research Database (Denmark)

    Jørgensen, Jacob Lykkebo; Gagliardi, Alessio; Pecchia, Alessandro

    2013-01-01

    . With this in mind, we investigate a spectroscopic method capable of providing insight into these junctions for cross-conjugated molecules: inelastic electron tunneling spectroscopy (IETS). IETS has the advantage that the molecule interface is probed directly by the tunneling current. Previously, it has been thought...... and leading to suppressed levels of elastic current. In most theoretical studies, only the elastic contributions to the current are taken into account. In this paper, we study the inelastic contributions to the current in cross-conjugated molecules and find that while the inelastic contribution to the current...

  17. Dynamical mean-field theory and path integral renormalisation group calculations of strongly correlated electronic states

    Energy Technology Data Exchange (ETDEWEB)

    Heilmann, D.B.

    2007-02-15

    The two-plane HUBBARD model, which is a model for some electronic properties of undoped YBCO superconductors as well as displays a MOTT metal-to-insulator transition and a metal-to-band insulator transition, is studied within Dynamical Mean-Field Theory using HIRSCH-FYE Monte Carlo. In order to find the different transitions and distinguish the types of insulator, we calculate the single-particle spectral densities, the self-energies and the optical conductivities. We conclude that there is a continuous transition from MOTT to band insulator. In the second part, ground state properties of a diagonally disordered HUBBARD model is studied using a generalisation of Path Integral Renormalisation Group, a variational method which can also determine low-lying excitations. In particular, the distribution of antiferromagnetic properties is investigated. We conclude that antiferromagnetism breaks down in a percolation-type transition at a critical disorder, which is not changed appreciably by the inclusion of correlation effects, when compared to earlier studies. Electronic and excitation properties at the system sizes considered turn out to primarily depend on the geometry. (orig.)

  18. Dynamical mean-field theory and path integral renormalisation group calculations of strongly correlated electronic states

    International Nuclear Information System (INIS)

    Heilmann, D.B.

    2007-02-01

    The two-plane HUBBARD model, which is a model for some electronic properties of undoped YBCO superconductors as well as displays a MOTT metal-to-insulator transition and a metal-to-band insulator transition, is studied within Dynamical Mean-Field Theory using HIRSCH-FYE Monte Carlo. In order to find the different transitions and distinguish the types of insulator, we calculate the single-particle spectral densities, the self-energies and the optical conductivities. We conclude that there is a continuous transition from MOTT to band insulator. In the second part, ground state properties of a diagonally disordered HUBBARD model is studied using a generalisation of Path Integral Renormalisation Group, a variational method which can also determine low-lying excitations. In particular, the distribution of antiferromagnetic properties is investigated. We conclude that antiferromagnetism breaks down in a percolation-type transition at a critical disorder, which is not changed appreciably by the inclusion of correlation effects, when compared to earlier studies. Electronic and excitation properties at the system sizes considered turn out to primarily depend on the geometry. (orig.)

  19. Measurement of Coherent Emission and Linear Polarization of Photons by Electrons in the Strong Fields of Aligned Crystals

    CERN Document Server

    Apyan, A.; Badelek, B.; Ballestrero, S.; Biino, C.; Birol, I.; Cenci, P.; Connell, S.H.; Eichblatt, S.; Fonseca, T.; Freund, A.; Gorini, B.; Groess, R.; Ispirian, K.; Ketel, T.J.; Kononets, Yu.V.; Lopez, A.; Mangiarotti, A.; van Rens, B.; Sellschop, J.P.F.; Shieh, M.; Sona, P.; Strakhovenko, V.; Uggerhoj, E.; Uggerhj, Ulrik Ingerslev; Unel, G.; Velasco, M.; Vilakazi, Z.Z.; Wessely, O.; Kononets, Yu.V.

    2004-01-01

    We present new results regarding the features of high energy photon emission by an electron beam of 178 GeV penetrating a 1.5 cm thick single Si crystal aligned at the Strings-Of-Strings (SOS) orientation. This concerns a special case of coherent bremsstrahlung where the electron interacts with the strong fields of successive atomic strings in a plane and for which the largest enhancement of the highest energy photons is expected. The polarization of the resulting photon beam was measured by the asymmetry of electron-positron pair production in an aligned diamond crystal analyzer. By the selection of a single pair the energy and the polarization of individual photons could be measured in an the environment of multiple photons produced in the radiator crystal. Photons in the high energy region show less than 20% linear polarization at the 90% confidence level.

  20. Laser-assisted electron scattering in strong-field ionization of dense water vapor by ultrashort laser pulses

    International Nuclear Information System (INIS)

    Wilke, M; Al-Obaidi, R; Moguilevski, A; Kothe, A; Engel, N; Metje, J; Kiyan, I Yu; Aziz, E F

    2014-01-01

    We report on strong-field ionization of dense water gas in a short infrared laser pulse. By employing a unique combination of photoelectron spectroscopy with a liquid micro-jet technique, we observe how the character of electron emission at high kinetic energies changes with the increase of the medium density. This change is associated with the process of laser-assisted electron scattering (LAES) on neighboring particles, which becomes a dominant mechanism of hot electron emission at higher medium densities. The manifestation of this mechanism is found to require densities that are orders of magnitude lower than those considered for heating the laser-generated plasmas via the LAES process. The experimental results are supported by simulations of the LAES yield with the use of the Kroll–Watson theory. (paper)

  1. Photoemission in strongly correlated crystalline f-electron systems: A need for a new approach

    International Nuclear Information System (INIS)

    Arko, A.J.; Joyce, J.J.; Sarrao, J.

    1998-01-01

    The unusual properties of heavy fermion (or heavy electron) materials have sparked an avalanche of research over the last two decades in order to understand the basic phenomena responsible for these properties. Photoelectron spectroscopy (often referred to as PES in the following sections), the most direct measurement of the electronic structure of a material, should in principle be able to shed considerable light on this matter. In general the distinction between a localized and a band-like state is trivially observed in band dispersion. Much of the past work was performed on poly-crystalline samples, scraped in-situ to expose a clean surface for PES. There have since been considerable advances both in the quality of specimens as well as experimental resolution, which raise questions regarding these conclusions. Much of the past work on poly-crystalline samples has been reported in several review articles, most notably Allen et al., and it is not necessary here to review those efforts again, with the exception of subsequent work performed at high resolution. The primary focus of the present review will be on new measurements obtained on single crystals, cleaved or prepared in situ and measured at high resolution, which seem to suggest that agreement with the GS and NCA approximations is less than perfect, and that perhaps the starting models need to be modified, or that even an entirely new approach is called for. Of the promising new models the Periodic Anderson Model is most closely related to the SIM. Indeed, at high temperatures it reverts to the SIM. However, the charge polaron model of Liu (1997) as well as the two-electron band model of Sheng and Cooper (1995) cannot yet be ruled out. Inasmuch as the bulk of the single crystal work was performed by the Los Alamos group, this review will draw heavily on those results. Moreover, since the GS and NCA approximations represent the most comprehensive and widely accepted treatment of heavy fermion PES, it is only

  2. Assessing the importance of frustration in a narrow-band strongly correlated electronic chain

    International Nuclear Information System (INIS)

    Lal, Siddhartha; Laad, Mukul S.

    2007-08-01

    We study a one-dimensional extended Hubbard model with longer-range Coulomb interactions at quarter-filling in the strong coupling limit. In this limit, we find the one dimensional transverse field Ising model (TFIM) to be the effective Hamiltonian governing the dynamics of the charge degrees of freedom. We find two different charge-ordered (CO) ground states as the strength of the longer range interactions is varied. At lower energies, these CO states drive two different spin-ordered ground states. A variety of response functions computed here bear a remarkable resemblance to recent experimental observations for organic TMTSF systems, and so we propose that these systems are proximate to a QCP associated with T = 0 charge order. (author)

  3. Footprints of electron correlation in strong-field double ionization of Kr close to the sequential-ionization regime

    Science.gov (United States)

    Li, Xiaokai; Wang, Chuncheng; Yuan, Zongqiang; Ye, Difa; Ma, Pan; Hu, Wenhui; Luo, Sizuo; Fu, Libin; Ding, Dajun

    2017-09-01

    By combining kinematically complete measurements and a semiclassical Monte Carlo simulation we study the correlated-electron dynamics in the strong-field double ionization of Kr. Interestingly, we find that, as we step into the sequential-ionization regime, there are still signatures of correlation in the two-electron joint momentum spectrum and, more intriguingly, the scaling law of the high-energy tail is completely different from early predictions on the low-Z atom (He). These experimental observations are well reproduced by our generalized semiclassical model adapting a Green-Sellin-Zachor potential. It is revealed that the competition between the screening effect of inner-shell electrons and the Coulomb focusing of nuclei leads to a non-inverse-square central force, which twists the returned electron trajectory at the vicinity of the parent core and thus significantly increases the probability of hard recollisions between two electrons. Our results might have promising applications ranging from accurately retrieving atomic structures to simulating celestial phenomena in the laboratory.

  4. Effects of strong electron correlations in Ti8C12 Met-Car

    International Nuclear Information System (INIS)

    Varganov, Sergey A.; Gordon, Mark S.

    2006-01-01

    The results of multireference configuration interaction (MRCI) with single and double excitations and single reference coupled cluster (CCSD(T)) calculations on Ti 8 C 12 metallocarbohedryne (Met-Car) are reported. The distortions of the T d structure to D 2d and C 3v structures due to the Jahn-Teller effect are studied. It is shown that the Ti 8 C 12 wave function has significant multireference character. The choice of the active space for multireference self-consistent field (MCSCF) calculations is discussed. The failure of multireference perturbation theory with a small active space is attributed to multiple intruder states. A new, novel type of MCSCF calculation, ORMAS (occupation restricted multiple active spaces) with a large active space are carried out for several electronic states of Ti 8 C 12 . The Jahn-Teller distorted D 2d 1 A 1 (nearly T d ) structure is predicted to be the Ti 8 C 12 ground state. Predictions of the Ti 8 C 12 ionization potential with different ab initio methods are presented

  5. Electronic transport through a quantum dot chain with strong dot-lead coupling

    International Nuclear Information System (INIS)

    Liu, Yu; Zheng, Yisong; Gong, Weijiang; Gao, Wenzhu; Lue, Tianquan

    2007-01-01

    By means of the non-equilibrium Green function technique, the electronic transport through an N-quantum-dot chain is theoretically studied. By calculating the linear conductance spectrum and the local density of states in quantum dots, we find the resonant peaks in the spectra coincides with the eigen-energies of the N-quantum-dot chain when the dot-lead coupling is relatively weak. With the increase of the dot-lead coupling, such a correspondence becomes inaccurate. When the dot-lead coupling exceeds twice the interdot coupling, such a mapping collapses completely. The linear conductance turn to reflect the eigen-energies of the (N-2)- or (N-1)-quantum dot chain instead. The two peripheral quantum dots do not manifest themselves in the linear conductance spectrum. More interestingly, with the further increase of the dot-lead coupling, the system behaves just like an (N-2)- or (N-1)-quantum dot chain in weak dot-lead coupling limit, since the resonant peaks becomes narrower with the increase of dot-lead coupling

  6. Final Report - Composite Fermion Approach to Strongly Interacting Quasi Two Dimensional Electron Gas Systems

    Energy Technology Data Exchange (ETDEWEB)

    Quinn, John

    2009-11-30

    Work related to this project introduced the idea of an effective monopole strength Q* that acted as the effective angular momentum of the lowest shell of composite Fermions (CF). This allowed us to predict the angular momentum of the lowest band of energy states for any value of the applied magnetic field simply by determining N{sub QP} the number of quasielectrons (QE) or quasiholes (QH) in a partially filled CF shell and adding angular momenta of the N{sub QP} Fermions excitations. The approach reported treated the filled CF level as a vacuum state which could support QE and QH excitations. Numerical diagonalization of small systems allowed us to determine the angular momenta, the energy, and the pair interaction energies of these elementary excitations. The spectra of low energy states could then be evaluated in a Fermi liquid-like picture, treating the much smaller number of quasiparticles and their interactions instead of the larger system of N electrons with Coulomb interactions.

  7. Ultrafast optical pump terahertz-probe spectroscopy of strongly correlated electron materials

    International Nuclear Information System (INIS)

    Averitt, R.D.; Taylor, Antoinette J.; Thorsmolle, V.K.; Jia, Quanxi; Lobad, A.I.; Trugman, S.A.

    2001-01-01

    We have used optical-pump far-infrared probe spectroscopy to probe the low energy electron dynamics of high temperature superconductors and colossal magnetoresistance manganites. For the superconductor YBa2Cu3O7, picosecond conductivity measurements probe the interplay between Cooper-pairs and quasiparticles. In optimally doped films, the recovery time for long-range phase-coherent pairing increases from ∼1.5 ps at 4K to ∼3.5 ps near Tc, consistent with the closing of the superconducting gap. For underdoped films, the measured recovery time is temperature independent (3.5 ps) in accordance with the presence of a pseudogap. Ultrafast picosecond measurements of optically induced changes in the absolute conductivity of La0:7M0:3MnO3 thin films (M = Ca, Sr) from 10K to ∼0.9Tc reveal a two-component relaxation. A fast, ∼2 ps, conductivity decrease arises from optically induced modification of the effective phonon temperature. The slower component, related to spin-lattice relaxation, has a lifetime that increases upon approaching Tc from below in accordance with an increasing spin specific heat. Our results indicate that for T<< Tc, the conductivity is determined by incoherent phonons while spin fluctuations dominate near Tc.

  8. Quantum criticality around metal-insulator transitions of strongly correlated electron systems

    Science.gov (United States)

    Misawa, Takahiro; Imada, Masatoshi

    2007-03-01

    Quantum criticality of metal-insulator transitions in correlated electron systems is shown to belong to an unconventional universality class with violation of the Ginzburg-Landau-Wilson (GLW) scheme formulated for symmetry breaking transitions. This unconventionality arises from an emergent character of the quantum critical point, which appears at the marginal point between the Ising-type symmetry breaking at nonzero temperatures and the topological transition of the Fermi surface at zero temperature. We show that Hartree-Fock approximations of an extended Hubbard model on square lattices are capable of such metal-insulator transitions with unusual criticality under a preexisting symmetry breaking. The obtained universality is consistent with the scaling theory formulated for Mott transitions and with a number of numerical results beyond the mean-field level, implying that preexisting symmetry breaking is not necessarily required for the emergence of this unconventional universality. Examinations of fluctuation effects indicate that the obtained critical exponents remain essentially exact beyond the mean-field level. It further clarifies the whole structure of singularities by a unified treatment of the bandwidth-control and filling-control transitions. Detailed analyses of the criticality, containing diverging carrier density fluctuations around the marginal quantum critical point, are presented from microscopic calculations and reveal the nature as quantum critical “opalescence.” The mechanism of emerging marginal quantum critical point is ascribed to a positive feedback and interplay between the preexisting gap formation present even in metals and kinetic energy gain (loss) of the metallic carrier. Analyses of crossovers between GLW type at nonzero temperature and topological type at zero temperature show that the critical exponents observed in (V,Cr)2O3 and κ-ET -type organic conductors provide us with evidence for the existence of the present marginal

  9. Effect of strong correlations on the high energy anomaly in hole- and electron-doped high-Tc superconductors

    International Nuclear Information System (INIS)

    Moritz, B; Johnston, S; Greven, M; Shen, Z-X; Devereaux, T P; Schmitt, F; Meevasana, W; Motoyama, E M; Lu, D H; Kim, C; Scalettar, R T

    2009-01-01

    Recently, angle-resolved photoemission spectroscopy (ARPES) has been used to highlight an anomalously large band renormalization at high binding energies in cuprate superconductors: the high energy 'waterfall' or high energy anomaly (HEA). This paper demonstrates, using a combination of new ARPES measurements and quantum Monte Carlo simulations, that the HEA is not simply the by-product of matrix element effects, but rather represents a cross-over from a quasi-particle band at low binding energies near the Fermi level to valence bands at higher binding energy, assumed to be of strong oxygen character, in both hole- and electron-doped cuprates. While photoemission matrix elements clearly play a role in changing the aesthetic appearance of the band dispersion, i.e. the 'waterfall'-like behavior, they provide an inadequate description for the physics that underlies the strong band renormalization giving rise to the HEA. Model calculations of the single-band Hubbard Hamiltonian showcase the role played by correlations in the formation of the HEA and uncover significant differences in the HEA energy scale for hole- and electron-doped cuprates. In addition, this approach properly captures the transfer of spectral weight accompanying both hole and electron doping in a correlated material and provides a unifying description of the HEA across both sides of the cuprate phase diagram.

  10. Subfemtosecond electron dynamics of H{sub 2} in strong fields or the quest for the molecular clock

    Energy Technology Data Exchange (ETDEWEB)

    Staudte, A.

    2005-07-01

    In this work we have studied experimentally and theoretically hydrogen and deuterium molecules in strong laser fields. We wanted to demonstrate that control of dynamical processes on the time scale below a single laser cycle (2.7 fs) can be achieved even without using attosecond pulses just by employing the advanced experimental technique COLTRIMS. In order to do this, we have pursued two goals: 1. To examine, whether laser steered electron wavepackets can be used for laser induced electron diffraction (LIED) on molecules. 2. To demonstrate, that the double ionization of H{sub 2} can be followed with sub laser cycle temporal resolution (the molecular clock). Laser induced electron diffraction needs linearly polarized light since its mechanism relies on rescattering of the ionized electron in the molecular potential. With rescattering occurring within a few hundred attoseconds, LIED is really a process of attosecond physics. In principle, two extreme scattering geometries are possible for a homonuclear diatomic molecule like H{sub 2}: the perpendicular geometry, which corresponds to the classical double slit experiment where the electron microbunch is steered transversely to the molecular axis, and the tangential geometry with the electron moving parallel to the molecular axis. Experimental restrictions prevented us to investigate the perpendicular geometry. The molecular clock, on the other hand, employs circularly polarized light to map the absolute phase of the laser electric field onto the spatial direction of the electron momentum. Thereby, a full laser cycle is mapped onto 360 in momentum space. Thus, different electron ejection angles in the laboratory frame correspond to different ejection times. Together with the correlated kinetic energy release of the Coulomb exploding molecules an unambiguous clock running from 0-8 fs with a few 100 as resolution can be envisioned. In direct relation to this experiment, we studied the influence of the long range

  11. Neonatal opioid withdrawal syndrome.

    Science.gov (United States)

    Sutter, Mary Beth; Leeman, Lawrence; Hsi, Andrew

    2014-06-01

    Neonatal opioid withdrawal syndrome is common due to the current opioid addiction epidemic. Infants born to women covertly abusing prescription opioids may not be identified as at risk until withdrawal signs present. Buprenorphine is a newer treatment for maternal opioid addiction and appears to result in a milder withdrawal syndrome than methadone. Initial treatment is with nonpharmacological measures including decreasing stimuli, however pharmacological treatment is commonly required. Opioid monotherapy is preferred, with phenobarbital or clonidine uncommonly needed as adjunctive therapy. Rooming-in and breastfeeding may decease the severity of withdrawal. Limited evidence is available regarding long-term effects of perinatal opioid exposure. Copyright © 2014 Elsevier Inc. All rights reserved.

  12. Electron spin resonance modes in a strong-leg ladder in the Tomonaga-Luttinger liquid phase

    Science.gov (United States)

    Ozerov, M.; Maksymenko, M.; Wosnitza, J.; Honecker, A.; Landee, C. P.; Turnbull, M. M.; Furuya, S. C.; Giamarchi, T.; Zvyagin, S. A.

    2015-12-01

    Magnetic excitations in the strong-leg quantum spin ladder compound (C7H10N) 2CuBr4 (known as DIMPY) in the field-induced Tomonaga-Luttinger spin-liquid phase are studied by means of high-field electron spin resonance (ESR) spectroscopy. The presence of a gapped ESR mode with unusual nonlinear frequency-field dependence is revealed experimentally. Using a combination of analytic and exact-diagonalization methods, we compute the dynamical structure factor and identify this mode with longitudinal excitations in the antisymmetric channel. We argue that these excitations constitute a fingerprint of the spin dynamics in a strong-leg spin-1/2 Heisenberg antiferromagnetic ladder and owe their ESR observability to the uniform Dzyaloshinskii-Moriya interaction.

  13. Imprints of the Molecular Electronic Structure in the Photoelectron Spectra of Strong-Field Ionized Asymmetric Triatomic Model Molecules

    Science.gov (United States)

    Paul, Matthias; Yue, Lun; Gräfe, Stefanie

    2018-06-01

    We examine the circular dichroism in the angular distribution of photoelectrons of triatomic model systems ionized by strong-field ionization. Following our recent work on this effect [Paul, Yue, and Gräfe, J. Mod. Opt. 64, 1104 (2017), 10.1080/09500340.2017.1299883], we demonstrate how the symmetry and electronic structure of the system is imprinted into the photoelectron momentum distribution. We use classical trajectories to reveal the origin of the threefolded pattern in the photoelectron momentum distribution, and show how an asymmetric nuclear configuration of the triatomic system effects the photoelectron spectra.

  14. The contribution of Diamond Light Source to the study of strongly correlated electron systems and complex magnetic structures.

    Science.gov (United States)

    Radaelli, P G; Dhesi, S S

    2015-03-06

    We review some of the significant contributions to the field of strongly correlated materials and complex magnets, arising from experiments performed at the Diamond Light Source (Harwell Science and Innovation Campus, Didcot, UK) during the first few years of operation (2007-2014). We provide a comprehensive overview of Diamond research on topological insulators, multiferroics, complex oxides and magnetic nanostructures. Several experiments on ultrafast dynamics, magnetic imaging, photoemission electron microscopy, soft X-ray holography and resonant magnetic hard and soft X-ray scattering are described. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

  15. Resolution-of-identity stochastic time-dependent configuration interaction for dissipative electron dynamics in strong fields.

    Science.gov (United States)

    Klinkusch, Stefan; Tremblay, Jean Christophe

    2016-05-14

    In this contribution, we introduce a method for simulating dissipative, ultrafast many-electron dynamics in intense laser fields. The method is based on the norm-conserving stochastic unraveling of the dissipative Liouville-von Neumann equation in its Lindblad form. The N-electron wave functions sampling the density matrix are represented in the basis of singly excited configuration state functions. The interaction with an external laser field is treated variationally and the response of the electronic density is included to all orders in this basis. The coupling to an external environment is included via relaxation operators inducing transition between the configuration state functions. Single electron ionization is represented by irreversible transition operators from the ionizing states to an auxiliary continuum state. The method finds its efficiency in the representation of the operators in the interaction picture, where the resolution-of-identity is used to reduce the size of the Hamiltonian eigenstate basis. The zeroth-order eigenstates can be obtained either at the configuration interaction singles level or from a time-dependent density functional theory reference calculation. The latter offers an alternative to explicitly time-dependent density functional theory which has the advantage of remaining strictly valid for strong field excitations while improving the description of the correlation as compared to configuration interaction singles. The method is tested on a well-characterized toy system, the excitation of the low-lying charge transfer state in LiCN.

  16. Resolution-of-identity stochastic time-dependent configuration interaction for dissipative electron dynamics in strong fields

    Energy Technology Data Exchange (ETDEWEB)

    Klinkusch, Stefan; Tremblay, Jean Christophe [Institute for Chemistry and Biochemistry, Freie Universität Berlin, Takustr. 3, D-14195 Berlin (Germany)

    2016-05-14

    In this contribution, we introduce a method for simulating dissipative, ultrafast many-electron dynamics in intense laser fields. The method is based on the norm-conserving stochastic unraveling of the dissipative Liouville-von Neumann equation in its Lindblad form. The N-electron wave functions sampling the density matrix are represented in the basis of singly excited configuration state functions. The interaction with an external laser field is treated variationally and the response of the electronic density is included to all orders in this basis. The coupling to an external environment is included via relaxation operators inducing transition between the configuration state functions. Single electron ionization is represented by irreversible transition operators from the ionizing states to an auxiliary continuum state. The method finds its efficiency in the representation of the operators in the interaction picture, where the resolution-of-identity is used to reduce the size of the Hamiltonian eigenstate basis. The zeroth-order eigenstates can be obtained either at the configuration interaction singles level or from a time-dependent density functional theory reference calculation. The latter offers an alternative to explicitly time-dependent density functional theory which has the advantage of remaining strictly valid for strong field excitations while improving the description of the correlation as compared to configuration interaction singles. The method is tested on a well-characterized toy system, the excitation of the low-lying charge transfer state in LiCN.

  17. Correlated electron-ion collisions in a strong laser field; Korrelierte Elektron-Ion-Stoesse in starken Laserfeldern

    Energy Technology Data Exchange (ETDEWEB)

    Ristow, T.

    2007-12-17

    Electron-ion-collisions in plasmas in the presence of an ultra-short intensive laser pulse can cause high energy transfers to the electrons. During the collision the oscillation energy of the electron in the laser field is changed into drift energy. In this regime, multi-photon processes, known from the ionization of neutral atoms (Above-Threshold Ionization), and successive, so called correlated collisions, are important. The subject of the thesis is a study of binary Coulomb collisions in strong laser fields. The collisions are treated both in the context of classical Newtonian mechanics and in the quantum-mechanical framework by the Schroedinger equation. In the classical case a simplified instantaneous collision model and a complete dynamical treatment are discussed. Collisions can be treated instantaneously, if the ratio of the impact parameter to the quiver amplitude is small. The energy distributions calculated in this approximation show an elastic peak and a broad plateau due to rescattered electrons. At incident velocities smaller than the quiver velocity, correlated collisions are observed in the electron trajectories of the dynamical model. This effect leads to characteristic momentum distributions of the electrons, that are explicitly calculated and compared with the results of the instantaneous model. In addition, the time-dependence of the collisions is discussed in the framework of a singular perturbation theory. The complete description of the Coulomb scattering requires a quantum-mechanical description. A time-dependent method of wave-packet scattering is used and the corresponding time-dependent three-dimensional Schroedinger equation is solved by an implicit ADImethod on a spatial grid. The momentum and the energy distributions of the scattered electrons are calculated by the Fourier transformation of the wavefunction. A comparison of the scattering from a repulsive and an attractive potential is used to distinguish between simple collisions and

  18. Electron-electron interaction in strong electromagnetic fields The two-electron contribution to the ground-state energy in He-like uranium

    CERN Document Server

    Gumberidze, A; Barnás, D; Beckert, Karl; Beller, Peter; Beyer, H F; Bosch, F; Cai, X; Stöhlker, T; Hagmann, S; Kozhuharov, C; Liesen, D; Nolden, F; Ma, X; Mokler, P H; Orsic-Muthig, A; Steck, Markus; Sierpowski, D; Tashenov, S; Warczak, A; Zou, Y

    2004-01-01

    Radiative recombination transitions into the ground state of cooled bare and hydrogen-like uranium ions were measured at the storage ring ESR. By comparing the corresponding x-ray centroid energies, this technique allows for a direct measurement of the electron-electron contribution to the ionization potential in the heaviest He-like ions. For the two-electron contribution to the ionization potential of He-like uranium we obtain a value of 2248 ± 9 eV. This represents the most accurate determination of two-electron effects in the domain of high-Z He-like ions and the accuracy reaches already the size of the specific two-electron radiative QED corrections.

  19. Treatment for amphetamine withdrawal.

    Science.gov (United States)

    Shoptaw, Steven J; Kao, Uyen; Heinzerling, Keith; Ling, Walter

    2009-04-15

    Few studies examined treatments for amphetamine withdrawal, although it is a common problem among amphetamine users. Its symptoms, in particular intense craving, may be a critical factor leading to relapse to amphetamine use. In clinical practice, medications for cocaine withdrawal are commonly used to manage amphetamine withdrawal although the pharmacodynamic and pharmacokinetic properties of these two illicit substances are different. To assess the effectiveness of pharmacological alone or in combination with psychosocial treatment for amphetamine withdrawals on discontinuation rates, global state, withdrawal symptoms, craving, and other outcomes. MEDLINE (1966 - 2008), CINAHL (1982 - 2008), PsycINFO (1806 - 2008), CENTRAL (Cochrane Library 2008 issue 2), references of obtained articles. All randomised controlled and clinical trials evaluating pharmacological and or psychosocial treatments (alone or combined) for people with amphetamine withdrawal symptoms. Two authors evaluated and extracted data independently. The data were extracted from intention-to-treat analyses. The Relative Risk (RR) with the 95% confidence interval (95% CI) was used to assess dichotomous outcomes. The Weighted Mean Difference (WMD) with 95% CI was used to assess continuous outcomes. Four randomised controlled trials (involving 125 participants) met the inclusion criteria for the review. Two studies found that amineptine significantly reduced discontinuation rates and improved overall clinical presentation, but did not reduce withdrawal symptoms or craving compared to placebo. The benefits of mirtazapine over placebo for reducing amphetamine withdrawal symptoms were not as clear. One study suggested that mirtazapine may reduce hyperarousal and anxiety symptoms associated with amphetamine withdrawal. A more recent study failed to find any benefit of mirtazapine over placebo on retention or on amphetamine withdrawal symptoms. No medication is effective for treatment of amphetamine

  20. Strongly correlated electrons at high pressure: an approach by inelastic X-Ray scattering; Electrons correles sous haute pression: une approche par diffusion inelastique des rayons X

    Energy Technology Data Exchange (ETDEWEB)

    Rueff, J.P

    2007-06-15

    Inelastic X-ray scattering (IXS) and associated methods has turn out to be a powerful alternative for high-pressure physics. It is an all-photon technique fully compatible with high-pressure environments and applicable to a vast range of materials. Standard focalization of X-ray in the range of 100 microns is typical of the sample size in the pressure cell. Our main aim is to provide an overview of experimental results obtained by IXS under high pressure in 2 classes of materials which have been at the origin of the renewal of condensed matter physics: strongly correlated transition metal oxides and rare-earth compounds. Under pressure, d and f-electron materials show behaviors far more complex that what would be expected from a simplistic band picture of electron delocalization. These spectroscopic studies have revealed unusual phenomena in the electronic degrees of freedom, brought up by the increased density, the changes in the charge-carrier concentration, the over-lapping between orbitals, and hybridization under high pressure conditions. Particularly we discuss about pressure induced magnetic collapse and metal-insulator transitions in 3d compounds and valence fluctuations phenomena in 4f and 5f compounds. Thanks to its superior penetration depth, chemical selectivity and resonant enhancement, resonant inelastic X-ray scattering has appeared extremely well suited to high pressure physics in strongly correlated materials. (A.C.)

  1. Organic sensitizers from D-π-A to D-A-π-A: effect of the internal electron-withdrawing units on molecular absorption, energy levels and photovoltaic performances.

    Science.gov (United States)

    Wu, Yongzhen; Zhu, Weihong

    2013-03-07

    The high performance and low cost of dye-sensitized solar cells (DSSCs) have drawn great interest from both academic and industrial circles. The research on exploring novel efficient sensitizers, especially on inexpensive metal-free pure organic dyes, has never been suspended. The donor-π bridge-acceptor (D-π-A) configuration is mainstream in the design of organic sensitizers due to its convenient modulation of the intramolecular charge-transfer nature. Recently, it has been found that incorporation of additional electron-withdrawing units (such as benzothiadiazole, benzotriazole, quinoxaline, phthalimide, diketopyrrolopyrrole, thienopyrazine, thiazole, triazine, cyanovinyl, cyano- and fluoro-substituted phenyl) into the π bridge as internal acceptors, termed the D-A-π-A configuration, displays several advantages such as tuning of the molecular energy levels, red-shift of the charge-transfer absorption band, and distinct improvement of photovoltaic performance and stability. We apply the D-A-π-A concept broadly to the organic sensitizers containing additional electron-withdrawing units between electron donors and acceptors. This review is projected to summarize the category of pure organic sensitizers on the basis of the D-A-π-A feature. By comparing the structure-property relationship of typical photovoltaic D-A-π-A dyes, the important guidelines in the design of such materials are highlighted.

  2. Quantifying the Clinical Significance of Cannabis Withdrawal

    Science.gov (United States)

    Allsop, David J.; Copeland, Jan; Norberg, Melissa M.; Fu, Shanlin; Molnar, Anna; Lewis, John; Budney, Alan J.

    2012-01-01

    Background and Aims Questions over the clinical significance of cannabis withdrawal have hindered its inclusion as a discrete cannabis induced psychiatric condition in the Diagnostic and Statistical Manual of Mental Disorders (DSM IV). This study aims to quantify functional impairment to normal daily activities from cannabis withdrawal, and looks at the factors predicting functional impairment. In addition the study tests the influence of functional impairment from cannabis withdrawal on cannabis use during and after an abstinence attempt. Methods and Results A volunteer sample of 49 non-treatment seeking cannabis users who met DSM-IV criteria for dependence provided daily withdrawal-related functional impairment scores during a one-week baseline phase and two weeks of monitored abstinence from cannabis with a one month follow up. Functional impairment from withdrawal symptoms was strongly associated with symptom severity (p = 0.0001). Participants with more severe cannabis dependence before the abstinence attempt reported greater functional impairment from cannabis withdrawal (p = 0.03). Relapse to cannabis use during the abstinence period was associated with greater functional impairment from a subset of withdrawal symptoms in high dependence users. Higher levels of functional impairment during the abstinence attempt predicted higher levels of cannabis use at one month follow up (p = 0.001). Conclusions Cannabis withdrawal is clinically significant because it is associated with functional impairment to normal daily activities, as well as relapse to cannabis use. Sample size in the relapse group was small and the use of a non-treatment seeking population requires findings to be replicated in clinical samples. Tailoring treatments to target withdrawal symptoms contributing to functional impairment during a quit attempt may improve treatment outcomes. PMID:23049760

  3. Quantifying the clinical significance of cannabis withdrawal.

    Directory of Open Access Journals (Sweden)

    David J Allsop

    Full Text Available Questions over the clinical significance of cannabis withdrawal have hindered its inclusion as a discrete cannabis induced psychiatric condition in the Diagnostic and Statistical Manual of Mental Disorders (DSM IV. This study aims to quantify functional impairment to normal daily activities from cannabis withdrawal, and looks at the factors predicting functional impairment. In addition the study tests the influence of functional impairment from cannabis withdrawal on cannabis use during and after an abstinence attempt.A volunteer sample of 49 non-treatment seeking cannabis users who met DSM-IV criteria for dependence provided daily withdrawal-related functional impairment scores during a one-week baseline phase and two weeks of monitored abstinence from cannabis with a one month follow up. Functional impairment from withdrawal symptoms was strongly associated with symptom severity (p=0.0001. Participants with more severe cannabis dependence before the abstinence attempt reported greater functional impairment from cannabis withdrawal (p=0.03. Relapse to cannabis use during the abstinence period was associated with greater functional impairment from a subset of withdrawal symptoms in high dependence users. Higher levels of functional impairment during the abstinence attempt predicted higher levels of cannabis use at one month follow up (p=0.001.Cannabis withdrawal is clinically significant because it is associated with functional impairment to normal daily activities, as well as relapse to cannabis use. Sample size in the relapse group was small and the use of a non-treatment seeking population requires findings to be replicated in clinical samples. Tailoring treatments to target withdrawal symptoms contributing to functional impairment during a quit attempt may improve treatment outcomes.

  4. Competition Between Radial Loss and EMIC Wave Scattering of MeV Electrons During Strong CME-shock Driven Storms

    Science.gov (United States)

    Hudson, M. K.; Jaynes, A. N.; Li, Z.; Malaspina, D.; Millan, R. M.; Patel, M.; Qin, M.; Shen, X.; Wiltberger, M. J.

    2017-12-01

    The two strongest storms of Solar Cycle 24, 17 March and 22 June 2015, provide a contrast between magnetospheric response to CME-shocks at equinox and solstice. The 17 March CME-shock initiated storm produced a stronger ring current response with Dst = - 223 nT, while the 22 June CME-shock initiated storm reached a minimum Dst = - 204 nT. The Van Allen Probes ECT instrument measured a dropout in flux for both events which can be characterized by magnetopause loss at higher L values prior to strong recovery1. However, rapid loss is seen at L 3 for the June storm at high energies with maximum drop in the 5.2 MeV channel of the REPT instrument coincident with the observation of EMIC waves in the H+ band by the EMFISIS wave instrument. The rapid time scale of loss can be determined from the 65 minute delay in passage of the Probe A relative to the Probe B spacecraft. The distinct behavior of lower energy electrons at higher L values has been modeled with MHD-test particle simulations, while the rapid loss of higher energy electrons is examined in terms of the minimum resonant energy criterion for EMIC wave scattering, and compared with the timescale for loss due to EMIC wave scattering which has been modeled for other storm events.2 1Baker, D. N., et al. (2016), Highly relativistic radiation belt electron acceleration, transport, and loss: Large solar storm events of March and June 2015, J. Geophys. Res. Space Physics, 121, 6647-6660, doi:10.1002/2016JA022502. 2Li, Z., et al. (2014), Investigation of EMIC wave scattering as the cause for the BARREL 17 January 2013 relativistic electron precipitation event: A quantitative comparison of simulation with observations, Geophys. Res. Lett., 41, 8722-8729, doi:10.1002/2014GL062273.

  5. Application of constrained deconvolution technique for reconstruction of electron bunch profile with strongly non-Gaussian shape

    Science.gov (United States)

    Geloni, G.; Saldin, E. L.; Schneidmiller, E. A.; Yurkov, M. V.

    2004-08-01

    An effective and practical technique based on the detection of the coherent synchrotron radiation (CSR) spectrum can be used to characterize the profile function of ultra-short bunches. The CSR spectrum measurement has an important limitation: no spectral phase information is available, and the complete profile function cannot be obtained in general. In this paper we propose to use constrained deconvolution method for bunch profile reconstruction based on a priori-known information about formation of the electron bunch. Application of the method is illustrated with practically important example of a bunch formed in a single bunch-compressor. Downstream of the bunch compressor the bunch charge distribution is strongly non-Gaussian with a narrow leading peak and a long tail. The longitudinal bunch distribution is derived by measuring the bunch tail constant with a streak camera and by using a priory available information about profile function.

  6. Application of constrained deconvolution technique for reconstruction of electron bunch profile with strongly non-Gaussian shape

    International Nuclear Information System (INIS)

    Geloni, G.; Saldin, E.L.; Schneidmiller, E.A.; Yurkov, M.V.

    2004-01-01

    An effective and practical technique based on the detection of the coherent synchrotron radiation (CSR) spectrum can be used to characterize the profile function of ultra-short bunches. The CSR spectrum measurement has an important limitation: no spectral phase information is available, and the complete profile function cannot be obtained in general. In this paper we propose to use constrained deconvolution method for bunch profile reconstruction based on a priori-known information about formation of the electron bunch. Application of the method is illustrated with practically important example of a bunch formed in a single bunch-compressor. Downstream of the bunch compressor the bunch charge distribution is strongly non-Gaussian with a narrow leading peak and a long tail. The longitudinal bunch distribution is derived by measuring the bunch tail constant with a streak camera and by using a priory available information about profile function

  7. Strongly anisotropic thermal conductivity and adequate breathability of bilayered films for heat management of on-skin electronics

    Science.gov (United States)

    Zhou, Tianle; Wei, Hao; Tan, Huaping; Wang, Xin; Zeng, Haibo; Liu, Xiaoheng; Nagao, Shijo; Koga, Hirotaka; Nogi, Masaya; Sugahara, Tohru; Suganuma, Katsuaki

    2018-07-01

    Thin-film wearable electronics are required to be directly laminated on to human skin for reliable, sensitive bio-sensing but with minimal irritation to the user after long-time use. Excellent heat management films with strongly anisotropic thermal conductivity (K) and adequate breathability are increasingly desirable for shielding the skin from heating while allowing the skin to breathe properly. Here, interfacial self-assembly of a graphene oxide (GO) film covering an ambient-dried bacterial cellulose aerogel (AD-BCA) film followed by laser reduction was proposed to prepare laser-reduced GO (L-rGO)/AD-BCA bilayered films. The AD-BCA substrate provides low cross-plane K (K ⊥  ≈  0.052 W mK‑1), high breathability, and high compressive and tensile resistance by ‘partially’ inheriting the pore structure from bacterial cellulose (BC) gel. The introduction of an upper L-rGO film, which is only 0.31 wt% content, dramatically increases the in-plane K (K // ) from 0.3 W mK‑1 in AD-BCA to 10.72 W mK‑1 owing to the highly in-plane oriented, continuous, uniform assembling geometry of the GO film; while K ⊥ decreases to a lower value of 0.033 W mK‑1, mainly owing to the air pockets between L-rGO multilayers caused by the laser reduction. The bilayered films achieve a K // /K ⊥ of 325, which is substantially larger even than that of graphite and similar polymer composites. They permit high transmission rates for water vapor (416.78 g/m2/day, >204 g/m2/day of normal skin) and O2 (449.35 cm3/m2/day). The combination of strongly anisotropic thermal conductivity and adequate breathability facilitates applications in heat management in on-skin electronics.

  8. Psychosis following Tramadol Withdrawal

    OpenAIRE

    Rajabizadeh, Ghodratolah; Kheradmand, Ali; Nasirian, Mansoureh

    2009-01-01

    Background: Tramadol is a centrally acting opioid analgesic used to treat moderate to sever pain. It has more advantage and less opioid adverse effects than conventional opioid analgesia. Case Report: This article reports a patient with tramadol dependency that had psychosis after tramadol withdrawal. Conclusion: By the increase of tramadol usage for relief of chronic pain, tramadol abuse and dependency is increased. Some of tramadol withdrawal symptoms are not related to opioid, for example ...

  9. 75 FR 12804 - Withdrawal of Regulatory Guide 8.6

    Science.gov (United States)

    2010-03-17

    ... ``Regulatory Guides'' in the NRC's Electronic Reading Room at http://www.nrc.gov/reading-rm/doc-collections... NUCLEAR REGULATORY COMMISSION [NRC-2010-0103] Withdrawal of Regulatory Guide 8.6 AGENCY: Nuclear Regulatory Commission. ACTION: Withdrawal of Regulatory Guide 8.6, ``Standard Test Procedure for Geiger-M...

  10. Sodium Valproate Withdrawal Correlates with Reduced Aggression

    Science.gov (United States)

    Pritchard, Duncan; Hoerger, Marguerite; Dyer, Tim; Graham, Nicola; Penney, Heather; Mace, F. Charles

    2014-01-01

    People with learning disabilities are sometimes prescribed psychotropic medication to help manage their challenging behaviour. This case study describes how a multicomponent behavioural intervention in conjunction with the systematic withdrawal of sodium valproate was strongly correlated with reduced aggression. No symptoms of bipolar disorder or…

  11. 75 FR 22868 - Withdrawal of Regulatory Guide

    Science.gov (United States)

    2010-04-30

    ...'s public Web site under ``Regulatory Guides'' in the NRC's Electronic Reading Room at http://www.nrc.gov/reading-rm/doc-collections . Regulatory guides are also available for inspection at the NRC's... NUCLEAR REGULATORY COMMISSION [NRC-2010-0167] Withdrawal of Regulatory Guide AGENCY: Nuclear...

  12. High resolution inelastic electron scattering on 90Zr at low momentum transfer and strong fragmentation of the magnetic quadrupole strength

    International Nuclear Information System (INIS)

    Meuer, D.; Frey, R.; Hoffmann, D.H.H.; Richter, A.; Spamer, E.; Titze, O.; Knuepfer, W.

    1980-01-01

    High-resolution (FWHM approx. 30 keV) inelastic electron scattering on 90 Zr at low momentum transfer (0.20 -1 ) has been used to study magnetic transitions at excitation energies Esub(x) = 8-10 MeV. The experimental data were analyzed in the distorted-wave Born approximation (DWBA) with wave functions calculated in the random phase approximation (RPA). Three Jsup(π) = 1 + states have been identified Esub(x) = 8.233, 9.000 and 9.371 MeV. There is some indication of further very fragmented dipole strength and the upper limit for the total M1 strength in the investigated energy region is ΣB(M1)up 2 sub(K). It is much smaller than any theoretical prediction. Furthermore, a large number of 2 - states has been observed, with the center of gravity located at Esub(x) approx. 9 MeV. These states carry a total strength of ΣB(M2)up = 1000 μ 2 sub(K) x fm 2 . Their strong fragmentation is in qualitative agreement with theoretical calculations, but the deduced strength is much smaller than theoretically predicted. In addition the distributions of spacings and radiative widths of the 2 - states are consistent with a Wigner and a Porter-Thomas distribution, respectively. (orig.)

  13. Two strongly correlated electron systems: the Kondo mode in the strong coupling limit and a 2-D model of electrons close to an electronic topological transition; Deux systemes d'electrons fortement correles: le modele de reseau Kondo dans la limite du couplage fort et un modele bidimensionnel d'electrons au voisinage d'une transition topologique electronique

    Energy Technology Data Exchange (ETDEWEB)

    Bouis, F

    1999-10-14

    Two strongly correlated electron systems are considered in this work, Kondo insulators and high Tc cuprates. Experiments and theory suggest on one hand that the Kondo screening occurs on a rather short length scale and on the other hand that the Kondo coupling is renormalized to infinity in the low energy limit. The strong coupling limit is then the logical approach although the real coupling is moderate. A systematic development is performed around this limit in the first part. The band structure of these materials is reproduced within this scheme. Magnetic fluctuations are also studied. The antiferromagnetic transition is examined in the case where fermionic excitations are shifted to high energy. In the second part, the Popov and Fedotov representation of spins is used to formulate the Kondo and the antiferromagnetic Heisenberg model in terms of a non-polynomial action of boson fields. In the third part the properties of high Tc cuprates are explained by a change of topology of the Fermi surface. This phenomenon would happen near the point of optimal doping and zero temperature. It results in the appearance of a density wave phase in the under-doped regime. The possibility that this phase has a non-conventional symmetry is considered. The phase diagram that described the interaction and coexistence of density wave and superconductivity is established in the mean-field approximation. The similarities with the experimental observations are numerous in particular those concerning the pseudo-gap and the behavior of the resistivity near optimal doping. (author)

  14. The alcohol withdrawal syndrome.

    LENUS (Irish Health Repository)

    McKeon, A

    2008-08-01

    The alcohol withdrawal syndrome (AWS) is a common management problem in hospital practice for neurologists, psychiatrists and general physicians alike. Although some patients have mild symptoms and may even be managed in the outpatient setting, others have more severe symptoms or a history of adverse outcomes that requires close inpatient supervision and benzodiazepine therapy. Many patients with AWS have multiple management issues (withdrawal symptoms, delirium tremens, the Wernicke-Korsakoff syndrome, seizures, depression, polysubstance abuse, electrolyte disturbances and liver disease), which requires a coordinated, multidisciplinary approach. Although AWS may be complex, careful evaluation and available treatments should ensure safe detoxification for most patients.

  15. Conducting a Withdrawal Survey.

    Science.gov (United States)

    Aldridge, Sue; Rowley, Jennifer

    2001-01-01

    A survey at Edge Hill College of Higher Education in Canada, designed to be part of the mechanism for monitoring and evaluating the quality of the student experience, revealed that key factors influencing withdrawal were: course not as expected, traveling difficulties, institution not as expected, domestic difficulties, and financial difficulties.…

  16. Anticonvulsants for alcohol withdrawal.

    Science.gov (United States)

    Minozzi, Silvia; Amato, Laura; Vecchi, Simona; Davoli, Marina

    2010-03-17

    Alcohol abuse and dependence represents a most serious health problem worldwide with major social, interpersonal and legal interpolations. Besides benzodiazepines, anticonvulsants are often used for the treatment of alcohol withdrawal symptoms. Anticonvulsants drugs are indicated for the treatment of alcohol withdrawal syndrome, alone or in combination with benzodiazepine treatments. In spite of the wide use, the exact role of the anticonvulsants for the treatment of alcohol withdrawal has not yet bee adequately assessed. To evaluate the effectiveness and safety of anticonvulsants in the treatment of alcohol withdrawal. We searched Cochrane Drugs and Alcohol Group' Register of Trials (December 2009), PubMed, EMBASE, CINAHL (1966 to December 2009), EconLIT (1969 to December 2009). Parallel searches on web sites of health technology assessment and related agencies, and their databases. Randomized controlled trials (RCTs) examining the effectiveness, safety and overall risk-benefit of anticonvulsants in comparison with a placebo or other pharmacological treatment. All patients were included regardless of age, gender, nationality, and outpatient or inpatient therapy. Two authors independently screened and extracted data from studies. Fifty-six studies, with a total of 4076 participants, met the inclusion criteria. Comparing anticonvulsants with placebo, no statistically significant differences for the six outcomes considered.Comparing anticonvulsant versus other drug, 19 outcomes considered, results favour anticonvulsants only in the comparison carbamazepine versus benzodiazepine (oxazepam and lorazepam) for alcohol withdrawal symptoms (CIWA-Ar score): 3 studies, 262 participants, MD -1.04 (-1.89 to -0.20), none of the other comparisons reached statistical significance.Comparing different anticonvulsants no statistically significant differences in the two outcomes considered.Comparing anticonvulsants plus other drugs versus other drugs (3 outcomes considered), results

  17. Is this ?complicated? opioid withdrawal?

    OpenAIRE

    Parkar, S.R.; Seethalakshmi, R; Adarkar, S; Kharawala, S

    2006-01-01

    Seven patients with opioid dependence admitted in the de-addiction centre for detoxification developed convulsions and delirium during the withdrawal phase. After ruling out all other possible causes of these complications, opioid withdrawal seemed to emerge as the most likely explanation. The unpredictability of the course of opioid dependence and withdrawal needs to be considered when treating patients with opioid dependence.

  18. Different Effect of the Additional Electron-Withdrawing Cyano Group in Different Conjugation Bridge: The Adjusted Molecular Energy Levels and Largely Improved Photovoltaic Performance.

    Science.gov (United States)

    Li, Huiyang; Fang, Manman; Hou, Yingqin; Tang, Runli; Yang, Yizhou; Zhong, Cheng; Li, Qianqian; Li, Zhen

    2016-05-18

    Four organic sensitizers (LI-68-LI-71) bearing various conjugated bridges were designed and synthesized, in which the only difference between LI-68 and LI-69 (or LI-70 and LI-71) was the absence/presence of the CN group as the auxiliary electron acceptor. Interestingly, compared to the reference dye of LI-68, LI-69 bearing the additional CN group exhibited the bad performance with the decreased Jsc and Voc values. However, once one thiophene moiety near the anchor group was replaced by pyrrole with the electron-rich property, the resultant LI-71 exhibited a photoelectric conversion efficiency increase by about 3 folds from 2.75% (LI-69) to 7.95% (LI-71), displaying the synergistic effect of the two moieties (CN and pyrrole). Computational analysis disclosed that pyrrole as the auxiliary electron donor (D') in the conjugated bridge can compensate for the lower negative charge in the electron acceptor, which was caused by the CN group as the electron trap, leading to the more efficient electron injection and better photovoltaic performance.

  19. Anomalous High-Energy Waterfall-Like Electronic Structure in 5 d Transition Metal Oxide Sr2IrO4 with a Strong Spin-Orbit Coupling

    Science.gov (United States)

    Liu, Yan; Yu, Li; Jia, Xiaowen; Zhao, Jianzhou; Weng, Hongming; Peng, Yingying; Chen, Chaoyu; Xie, Zhuojin; Mou, Daixiang; He, Junfeng; Liu, Xu; Feng, Ya; Yi, Hemian; Zhao, Lin; Liu, Guodong; He, Shaolong; Dong, Xiaoli; Zhang, Jun; Xu, Zuyan; Chen, Chuangtian; Cao, Gang; Dai, Xi; Fang, Zhong; Zhou, X. J.

    2015-08-01

    The low energy electronic structure of Sr2IrO4 has been well studied and understood in terms of an effective Jeff = 1/2 Mott insulator model. However, little work has been done in studying its high energy electronic behaviors. Here we report a new observation of the anomalous high energy electronic structure in Sr2IrO4. By taking high-resolution angle-resolved photoemission measurements on Sr2IrO4 over a wide energy range, we have revealed for the first time that the high energy electronic structures show unusual nearly-vertical bands that extend over a large energy range. Such anomalous high energy behaviors resemble the high energy waterfall features observed in the cuprate superconductors. While strong electron correlation plays an important role in producing high energy waterfall features in the cuprate superconductors, the revelation of the high energy anomalies in Sr2IrO4, which exhibits strong spin-orbit coupling and a moderate electron correlation, points to an unknown and novel route in generating exotic electronic excitations.

  20. Anomalous High-Energy Waterfall-Like Electronic Structure in 5 d Transition Metal Oxide Sr2IrO4 with a Strong Spin-Orbit Coupling.

    Science.gov (United States)

    Liu, Yan; Yu, Li; Jia, Xiaowen; Zhao, Jianzhou; Weng, Hongming; Peng, Yingying; Chen, Chaoyu; Xie, Zhuojin; Mou, Daixiang; He, Junfeng; Liu, Xu; Feng, Ya; Yi, Hemian; Zhao, Lin; Liu, Guodong; He, Shaolong; Dong, Xiaoli; Zhang, Jun; Xu, Zuyan; Chen, Chuangtian; Cao, Gang; Dai, Xi; Fang, Zhong; Zhou, X J

    2015-08-12

    The low energy electronic structure of Sr2IrO4 has been well studied and understood in terms of an effective Jeff = 1/2 Mott insulator model. However, little work has been done in studying its high energy electronic behaviors. Here we report a new observation of the anomalous high energy electronic structure in Sr2IrO4. By taking high-resolution angle-resolved photoemission measurements on Sr2IrO4 over a wide energy range, we have revealed for the first time that the high energy electronic structures show unusual nearly-vertical bands that extend over a large energy range. Such anomalous high energy behaviors resemble the high energy waterfall features observed in the cuprate superconductors. While strong electron correlation plays an important role in producing high energy waterfall features in the cuprate superconductors, the revelation of the high energy anomalies in Sr2IrO4, which exhibits strong spin-orbit coupling and a moderate electron correlation, points to an unknown and novel route in generating exotic electronic excitations.

  1. CONSUMER'S RIGHT TO WITHDRAW

    Directory of Open Access Journals (Sweden)

    ANCA NICOLETA GHEORGHE

    2013-05-01

    Full Text Available The right of withdrawal (of a contract belongs to the consumer, and is an essential means for the improvement of regulations that protect the consumer.. Right of withdrawal is not a recent creation and is not even specific to the consumer field. He was previously recognized in civil and commercial law (without special regulation. The right to withdraw may even have as ground the parties will. Thus, based on the contractual freedom, the parties may agree that one of them has the right to terminate the contract unilaterally The possibility of unilateral denunciation of the contract, gives the consumer, added protection by being able to reflect the decision and to check how the trader fulfil its obligations. In this context, through its effects, the right of denunciation, forces the professional parties to conduct themselves as fair as possible to the consumer and to execute the contract properly. In the study of the consumer protection, the time of conclusion is essential because in this stage is manifested, the inequality between the consumer and professional. Thus, the lack of information, the major of products and activities, commercial practices, influence the formation of consumer will, preventing the expression of a freely and knowingly consent.

  2. PARTICLE-IN-CELL SIMULATION OF A STRONG DOUBLE LAYER IN A NONRELATIVISTIC PLASMA FLOW: ELECTRON ACCELERATION TO ULTRARELATIVISTIC SPEEDS

    International Nuclear Information System (INIS)

    Dieckmann, Mark E.; Bret, Antoine

    2009-01-01

    Two charge- and current-neutral plasma beams are modeled with a one-dimensional particle-in-cell simulation. The beams are uniform and unbounded. The relative speed between both beams is 0.4c. One beam is composed of electrons and protons, and the other of protons and negatively charged oxygen (dust). All species have the temperature 9.1 keV. A Buneman instability develops between the electrons of the first beam and the protons of the second beam. The wave traps the electrons, which form plasmons. The plasmons couple energy into the ion acoustic waves, which trap the protons of the second beam. A structure similar to a proton phase-space hole develops, which grows through its interaction with the oxygen and the heated electrons into a rarefaction pulse. This pulse drives a double layer, which accelerates a beam of electrons to about 50 MeV, which is comparable to the proton kinetic energy. The proton distribution eventually evolves into an electrostatic shock. Beams of charged particles moving at such speeds may occur in the foreshock of supernova remnant (SNR) shocks. This double layer is thus potentially relevant for the electron acceleration (injection) into the diffusive shock acceleration by SNR shocks.

  3. Linear temperature behavior of thermopower and strong electron-electron scattering in thick F-doped SnO2 films

    Science.gov (United States)

    Lang, Wen-Jing; Li, Zhi-Qing

    2014-07-01

    Both the semi-classical and quantum transport properties of F-doped SnO2 thick films (˜1 μm) were investigated experimentally. We found that the resistivity caused by the thermal phonons obeys Bloch-Grüneisen law from ˜90 to 300 K, while only the diffusive thermopower, which varies linearly with temperature from 300 down to 10 K, can be observed. The phonon-drag thermopower is completely suppressed due to the long electron-phonon relaxation time in the compound. These observations, together with the fact that the carrier concentration has negligible temperature dependence, indicate that the conduction electrons in F-doped SnO2 films possess free-electron-like characteristics. At low temperatures, the electron-electron scattering dominates over the electron-phonon scattering and governs the inelastic scattering process. The theoretical predications of scattering rates of large- and small-energy-transfer electron-electron scattering processes, which are negligibly weak in three-dimensional disordered conventional conductors, are quantitatively tested in this lower carrier concentration and free-electron-like highly degenerate semiconductor.

  4. Linear temperature behavior of thermopower and strong electron-electron scattering in thick F-doped SnO2 films

    International Nuclear Information System (INIS)

    Lang, Wen-Jing; Li, Zhi-Qing

    2014-01-01

    Both the semi-classical and quantum transport properties of F-doped SnO 2 thick films (∼1 μm) were investigated experimentally. We found that the resistivity caused by the thermal phonons obeys Bloch-Grüneisen law from ∼90 to 300 K, while only the diffusive thermopower, which varies linearly with temperature from 300 down to 10 K, can be observed. The phonon-drag thermopower is completely suppressed due to the long electron-phonon relaxation time in the compound. These observations, together with the fact that the carrier concentration has negligible temperature dependence, indicate that the conduction electrons in F-doped SnO 2 films possess free-electron-like characteristics. At low temperatures, the electron-electron scattering dominates over the electron-phonon scattering and governs the inelastic scattering process. The theoretical predications of scattering rates of large- and small-energy-transfer electron-electron scattering processes, which are negligibly weak in three-dimensional disordered conventional conductors, are quantitatively tested in this lower carrier concentration and free-electron-like highly degenerate semiconductor.

  5. Assessment of Blasting Performance Using Electronic Vis-à-Vis Shock Tube Detonators in Strong Garnet Biotite Sillimanite Gneiss Formations

    Science.gov (United States)

    Sharma, Suresh Kumar; Rai, Piyush

    2016-04-01

    This paper presents a comparative investigation of the shock tube and electronic detonating systems practised in bench blasting. The blast trials were conducted on overburden rocks of Garnet Biotite Sillimanite Gneiss formations in one of the largest metalliferous mine of India. The study revealed that the choice of detonating system was crucial in deciding the fragment size and its distribution within the blasted muck-piles. The fragment size and its distribution affected the digging rate of excavators. Also, the shape of the blasted muck-pile was found to be related to the degree of fragmentation. From the present work, it may be inferred that in electronic detonation system, timely release of explosive energy resulted in better overall blasting performance. Hence, the precision in delay time must be considered in designing blast rounds in such overburden rock formations. State-of-art image analysis, GPS based muck-pile profile plotting techniques were rigorously used in the investigation. The study revealed that a mean fragment size (K50) value for shock tube detonated blasts (0.55-0.59 m) was higher than that of electronically detonated blasts (0.43-0.45 m). The digging rate of designated shovels (34 m3) with electronically detonated blasts was consistently more than 5000 t/h, which was almost 13 % higher in comparison to shock tube detonated blasts. Furthermore, favourable muck-pile shapes were witnessed in electronically detonated blasts from the observations made on the dozer performance.

  6. High-performance n-type organic semiconductors: incorporating specific electron-withdrawing motifs to achieve tight molecular stacking and optimized energy levels.

    Science.gov (United States)

    Yun, Sun Woo; Kim, Jong H; Shin, Seunghoon; Yang, Hoichang; An, Byeong-Kwan; Yang, Lin; Park, Soo Young

    2012-02-14

    Novel π–conjugated cyanostilbene-based semiconductors (Hex-3,5-TFPTA and Hex-4-TFPTA) with tight molecular stacking and optimized energy levels are synthesized. Hex-4-TFPTA exhibits high-performance n-type organic field-effect transistor (OFET) properties with electron mobilities as high as 2.14 cm2 V−1s−1 and on-off current ratios Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Observation of topological surface states and strong electron/hole imbalance in extreme magnetoresistance compound LaBi

    Science.gov (United States)

    Jiang, J.; Schröter, N. B. M.; Wu, S.-C.; Kumar, N.; Shekhar, C.; Peng, H.; Xu, X.; Chen, C.; Yang, H. F.; Hwang, C.-C.; Mo, S.-K.; Felser, C.; Yan, B. H.; Liu, Z. K.; Yang, L. X.; Chen, Y. L.

    2018-02-01

    The recent discovery of the extreme magnetoresistance (XMR) in the nonmagnetic rare-earth monopnictides La X (X = P, As, Sb, Bi,), a recently proposed new topological semimetal family, has inspired intensive research effort in the exploration of the correlation between the XMR and their electronic structures. In this work, using angle-resolved photoemission spectroscopy to investigate the three-dimensional band structure of LaBi, we unraveled its topologically nontrivial nature with the observation of multiple topological surface Dirac fermions, as supported by our ab initio calculations. Furthermore, we observed substantial imbalance between the volume of electron and hole pockets, which rules out the electron-hole compensation as the primary cause of the XMR in LaBi.

  8. Inducing Strong Density Modulation with Small Energy Dispersion in Particle Beams and the Harmonic Amplifier Free Electron Laser

    CERN Document Server

    McNeil, Brian W J; Robb, Gordon

    2005-01-01

    We present a possible method of inducing a periodic density modulation in a particle beam with little increase in the energy dispersion of the particles. The flow of particles in phase space does not obey Liouville's Theorem. The method relies upon the Kuramoto-like model of collective synchronism found in free electron generators of radiation, such as Cyclotron Resonance Masers and the Free Electron Laser. For the case of an FEL interaction, electrons initially begin to bunch and emit radiation energy with a correlated energy dispersion which is periodic with the FEL ponderomotive potential. The relative phase between potential and particles is then changed by approximately 180 degrees. The particles continue to bunch, however, there is now a correlated re-absorption of energy from the field. We show that, by repeating this relative phase change many times, a significant density modulation of the particles may be achieved with only relatively small energy dispersion. A similar method of repeated relative ele...

  9. Phonon-assisted hopping of an electron on a Wannier-Stark ladder in a strong electric field

    International Nuclear Information System (INIS)

    Emin, D.; Hart, C.F.

    1987-01-01

    With the application of a spatially constant electric field, the degeneracy of electronic energy levels of geometrically equivalent sites of a crystal is generally lifted. As a result, the electric field causes the electronic eigenstates of a one-dimensional periodic chain to become localized. In particular, they are Wannier-Stark states. With sufficiently large electric-field strengths these states become sufficiently well localized that it becomes appropriate to consider electronic transport to occur via a succession of phonon-assisted hops between the localized Wannier-Stark states. In this paper, we present calculations of the drift velocity arising from acoustic- and optical-phonon-assisted hopping motion between Wannier-Stark states. When the intersite electronic transfer energy is sufficiently small so that the Wannier-Stark states are essentially each confined to a single atomic site, the transport reduces to that of a small polaron. In this regime, while the drift velocity initially rises with increasing electric field strength, the drift velocity ultimately falls with increasing electric-field strength at extremely large electric fields. More generally, for common values of the electronic bandwidth and electric field strength, the Wannier-Stark states span many sites. At sufficiently large electric fields, the energy separation between Wannier-Stark states exceeds the energy uncertainty associated with the carrier's interaction with phonons. Then, it is appropriate to treat the electronic transport in terms of phonon-assisted hopping between Wannier-Stark states. The resulting high-field drift velocity falls with increasing field strength in a series of steps. Thus, we find a structured negative differential mobility at large electric fields

  10. STRONG CORRELATIONS AND ELECTRON-PHONON COUPLING IN HIGH-TEMPERATURE SUPERCONDUCTORS - A QUANTUM MONTE-CARLO STUDY

    NARCIS (Netherlands)

    MORGENSTERN, [No Value; FRICK, M; VONDERLINDEN, W

    We present quantum simulation studies for a system of strongly correlated fermions coupled to local anharmonic phonons. The Monte Carlo calculations are based on a generalized version of the Projector Quantum Monte Carlo Method allowing a simultaneous treatment of fermions and dynamical phonons. The

  11. Analytic expressions for the dielectric screening function of strongly coupled electron liquids at metallic and lower densities

    International Nuclear Information System (INIS)

    Ishimaru, S.; Utsumi, K.

    1981-01-01

    We propose a fitting formula for the dielectric screening function of the degenerate electron liquids at metallic and lower densities which accurately reproduces the recent Monte Carlo results as well as those of the microscopic calculations, and which satisfies the self-consistency conditions in the compressibility sum rule and the short-range correlation

  12. Antidiabetic Theory of Superconducting State Transition: Phonons and Strong Electron Correlations the Old Physics and New Aspects

    International Nuclear Information System (INIS)

    Banacky, P.

    2010-01-01

    Complex electronic ground state of molecular and solid state system is analyzed on the ab initio level beyond the adiabatic Born-Oppenheimer approximation (BOA). The attention is focused on the band structure fluctuation (BSF) at Fermi level, which is induced by electron-phonon coupling in superconductors, and which is absent in the non-superconducting analogues. The BSF in superconductors results in breakdown of the adiabatic BOA. At these circumstances, chemical potential is substantially reduced and system is stabilized (effect of nuclear dynamics) in the anti adiabatic state at broken symmetry with a gap(s) in one-particle spectrum. Distorted nuclear structure has fluxional character and geometric degeneracy of the anti adiabatic ground state enables formation of mobile bipolarons in real space. It has been shown that an effective attractive e-e interaction (Cooper-pair formation) is in fact correction to electron correlation energy at transition from adiabatic into anti adiabatic ground electronic state. In this respect, Cooper-pair formation is not the primary reason for transition into superconducting state, but it is a consequence of anti adiabatic state formation. It has been shown that thermodynamic properties of system in anti adiabatic state correspond to thermodynamics of superconducting state. Illustrative application of the theory for different types of superconductors is presented.

  13. Evolution of the Fermi surface of the strongly correlated f electron system under hydrostatic and uniaxial pressures

    CERN Document Server

    Aoki, H; Endo, M; Nakayama, M; Takei, H; Kimura, N; Kunii, S; Terashima, T; Uji, S; Matsumoto, T

    2002-01-01

    We report our recent developments of experimental systems for measuring the de Haas-van Alphen (dHvA) effect under hydrostatic and uniaxial pressures. The dHvA effect of CeB sub 6 has been studied under both hydrostatic and uniaxial pressures and the effects of the pressures on the electronic structure are discussed.

  14. Strong correlation in acene sheets from the active-space variational two-electron reduced density matrix method: effects of symmetry and size.

    Science.gov (United States)

    Pelzer, Kenley; Greenman, Loren; Gidofalvi, Gergely; Mazziotti, David A

    2011-06-09

    Polyaromatic hydrocarbons (PAHs) are a class of organic molecules with importance in several branches of science, including medicine, combustion chemistry, and materials science. The delocalized π-orbital systems in PAHs require highly accurate electronic structure methods to capture strong electron correlation. Treating correlation in PAHs has been challenging because (i) traditional wave function methods for strong correlation have not been applicable since they scale exponentially in the number of strongly correlated orbitals, and (ii) alternative methods such as the density-matrix renormalization group and variational two-electron reduced density matrix (2-RDM) methods have not been applied beyond linear acene chains. In this paper we extend the earlier results from active-space variational 2-RDM theory [Gidofalvi, G.; Mazziotti, D. A. J. Chem. Phys. 2008, 129, 134108] to the more general two-dimensional arrangement of rings--acene sheets--to study the relationship between geometry and electron correlation in PAHs. The acene-sheet calculations, if performed with conventional wave function methods, would require wave function expansions with as many as 1.5 × 10(17) configuration state functions. To measure electron correlation, we employ several RDM-based metrics: (i) natural-orbital occupation numbers, (ii) the 1-RDM von Neumann entropy, (iii) the correlation energy per carbon atom, and (iv) the squared Frobenius norm of the cumulant 2-RDM. The results confirm a trend of increasing polyradical character with increasing molecular size previously observed in linear PAHs and reveal a corresponding trend in two-dimensional (arch-shaped) PAHs. Furthermore, in PAHs of similar size they show significant variations in correlation with geometry. PAHs with the strictly linear geometry (chains) exhibit more electron correlation than PAHs with nonlinear geometries (sheets).

  15. Electromagnetic radiation from positive-energy bound electrons in the Coulomb field of a nucleus at rest in a strong uniform magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Arsenyev, S. A.; Koryagin, S. A., E-mail: koryagin@appl.sci-nnov.ru [Russian Academy of Sciences, Institute of Applied Physics (Russian Federation)

    2012-06-15

    A classical analysis is presented of the electromagnetic radiation emitted by positive-energy electrons performing bound motion in the Coulomb field of a nucleus at rest in a strong uniform magnetic field. Bounded trajectories exist and span a wide range of velocity directions near the nucleus (compared to free trajectories with similar energies) when the electron Larmor radius is smaller than the distance at which the electron-nucleus Coulomb interaction energy is equal to the mechanical energy of an electron. The required conditions occur in magnetic white dwarf photospheres and have been achieved in experiments on production of antihydrogen. Under these conditions, the radiant power per unit volume emitted by positive-energy bound electrons is much higher than the analogous characteristic of bremsstrahlung (in particular, in thermal equilibrium) at frequencies that are below the electron cyclotron frequency but higher than the inverse transit time through the interaction region in a close collision in the absence of a magnetic field. The quantum energy discreteness of positive-energy bound states restricts the radiation from an ensemble of bound electrons (e.g., in thermal equilibrium) to nonoverlapping spectral lines, while continuum radiative transfer is dominated by linearly polarized bremsstrahlung.

  16. X-ray Diffraction from Isolated and Strongly Aligned Gas-Phase Molecules with a Free-Electron Laser

    DEFF Research Database (Denmark)

    Küpper, Jochen; Stern, Stephan; Holmegaard, Lotte

    2014-01-01

    We report experimental results on x-ray diffraction of quantum-state-selected and strongly aligned ensembles of the prototypical asymmetric rotor molecule 2,5-diiodobenzonitrile using the Linac Coherent Light Source. The experiments demonstrate first steps toward a new approach to diffractive...... imaging of distinct structures of individual, isolated gas-phase molecules. We confirm several key ingredients of single molecule diffraction experiments: the abilities to detect and count individual scattered x-ray photons in single shot diffraction data, to deliver state-selected, e. g., structural......-isomer-selected, ensembles of molecules to the x-ray interaction volume, and to strongly align the scattering molecules. Our approach, using ultrashort x-ray pulses, is suitable to study ultrafast dynamics of isolated molecules....

  17. Radiation from a Relativistic Electron Beam in a Molecular Medium due to Parametric Pumping by a Strong Electromagnetic Wave,

    Science.gov (United States)

    1981-02-01

    UNIVERSITY OF MARYLAND DEPARTMENT OF PHYSICS 4WJD ASTRONOMY COLLG PAM A 2 3i 81 4 30) 235. RADIATION FROM A .ELATIVISTIC_§LECTRON BEAM IN AZOLECULAR...A MOLECULAR MEDIUM DUE TO PARAMETRIC PUMPING BY A STRONG ELECTROMAGNETIC WAVE L. Stenflo Department of Plasma Physics Umel University S-90187 Umel...GUteborg, Sweden and Laboratory for Plasma and Fusion Energy Studies University of Maryland College Park, Maryland 20742 Physics Publication Number 81

  18. Nonlinear excitation of electron cyclotron waves by a monochromatic strong microwave: computer simulation analysis of the MINIX results

    Energy Technology Data Exchange (ETDEWEB)

    Matsumoto, H.; Kimura, T.

    1986-01-01

    Triggered by the experimental results of the MINIX, a computer simulation study was initiated on the nonlinear excitation of electrostatic electron cyclotron waves by a monochromatic electromagnetic wave such as the transmitted microwave in the MINIX. The model used assumes that both of the excited waves and exciting (pumping) electromagnetic wave as well as the idler electromagnetic wave propagate in the direction perpendicular to the external magnetic field. The simulation code used for this study was the one-and-two-half dimensional electromagnetic particle code named KEMPO. The simulation result shows the high power electromagnetic wave produces both the backscattered electromagnetic wave and electrostatic electron cyclotron waves as a result of nonlinear parametric instability. Detailed nonlinear microphysics related to the wave excitation is discussed in terms of the nonlinear wave-wave couplings and associated ponderomotive force produced by the high power electromagnetic waves. 2 references, 4 figures.

  19. Nonlinear excitation of electron cyclotron waves by a monochromatic strong microwave: computer simulation analysis of the MINIX results

    International Nuclear Information System (INIS)

    Matsumoto, H.; Kimura, T.

    1986-01-01

    Triggered by the experimental results of the MINIX, a computer simulation study was initiated on the nonlinear excitation of electrostatic electron cyclotron waves by a monochromatic electromagnetic wave such as the transmitted microwave in the MINIX. The model used assumes that both of the excited waves and exciting (pumping) electromagnetic wave as well as the idler electromagnetic wave propagate in the direction perpendicular to the external magnetic field. The simulation code used for this study was the one-and-two-half dimensional electromagnetic particle code named KEMPO. The simulation result shows the high power electromagnetic wave produces both the backscattered electromagnetic wave and electrostatic electron cyclotron waves as a result of nonlinear parametric instability. Detailed nonlinear microphysics related to the wave excitation is discussed in terms of the nonlinear wave-wave couplings and associated ponderomotive force produced by the high power electromagnetic waves. 2 references, 4 figures

  20. Spontaneous breaking of time-reversal symmetry in strongly interacting two-dimensional electron layers in silicon and germanium.

    Science.gov (United States)

    Shamim, S; Mahapatra, S; Scappucci, G; Klesse, W M; Simmons, M Y; Ghosh, A

    2014-06-13

    We report experimental evidence of a remarkable spontaneous time-reversal symmetry breaking in two-dimensional electron systems formed by atomically confined doping of phosphorus (P) atoms inside bulk crystalline silicon (Si) and germanium (Ge). Weak localization corrections to the conductivity and the universal conductance fluctuations were both found to decrease rapidly with decreasing doping in the Si:P and Ge:P delta layers, suggesting an effect driven by Coulomb interactions. In-plane magnetotransport measurements indicate the presence of intrinsic local spin fluctuations at low doping, providing a microscopic mechanism for spontaneous lifting of the time-reversal symmetry. Our experiments suggest the emergence of a new many-body quantum state when two-dimensional electrons are confined to narrow half-filled impurity bands.

  1. Entanglement dynamics of two electron-spin qubits in a strongly detuned and dissipative quantum-dot-cavity system

    International Nuclear Information System (INIS)

    Xiang Shaohua; Deng Xiaopeng; Song Kehui; Wen Wei; Shi Zhengang

    2011-01-01

    We investigate the entanglement dynamics of two electron-spin qubits in the quantum-dot (QD)-microcavity system in the large-detuning limit and subjected to two different noise sources: electron-spin dephasing and relaxation. We show that when one of the two dots is prepared initially in the excited state, the created entanglement exhibits oscillatory behavior at the beginning of evolution and then completely disappears over time. For two QDs that are initially in either the Einstein-Podolsky-Rosen-Bell states or the Werner states, their entanglement evolution exhibits the same behavior in the presence of pure dephasing, but is completely different under the relaxation process. We also show that the interdot interaction induced by a single-mode cavity field does not contribute to the dynamics of entanglement for these Bell states and Werner states.

  2. Strong forward-backward asymmetries in electron emission from overlapping resonance states in fast C3+ on He collisions

    International Nuclear Information System (INIS)

    Yamazaki, Y.; Miller, P.D.; Krause, H.F.; Pepmiller, P.L.; Datz, S.; Sellin, I.A.

    1986-01-01

    Autoionizing electrons from the configuration 1s 2 2pnl produced by transfer and excitation were measured for 2.5 to 5.0 MeV C 3+ + He-gas collision employing the method of zero-degree Auger spectroscopy. The elctron analyzer was operated with an energy resolution of 300 MeV (FWHM), which corresponds to the projectile rest frame energy resolution (approx.40 MeV)

  3. Perturbation theory for the bloch electrons on strongly coupled chains in both uniform electric and magnetic fields

    International Nuclear Information System (INIS)

    Zhao, X.G.; Chen, S.G.

    1992-01-01

    In this paper, the energy spectrum and the wave functions for a tight-binding Bloch electron on coupled chains under the action of both uniform electric and magnetic fields are studied in detail. Exact results are obtained for the case when the coupling between chains is large by using the perturbation theory, from which it is found that the spectrum is that of two interspaced Stark ladders. The magnetic field dependence of the energy spectrum is also discussed

  4. Electron-mediated relaxation following ultrafast pumping of strongly correlated materials: model evidence of a correlation-tuned crossover between thermal and nonthermal states.

    Science.gov (United States)

    Moritz, B; Kemper, A F; Sentef, M; Devereaux, T P; Freericks, J K

    2013-08-16

    We examine electron-electron mediated relaxation following ultrafast electric field pump excitation of the fermionic degrees of freedom in the Falicov-Kimball model for correlated electrons. The results reveal a dichotomy in the temporal evolution of the system as one tunes through the Mott metal-to-insulator transition: in the metallic regime relaxation can be characterized by evolution toward a steady state well described by Fermi-Dirac statistics with an increased effective temperature; however, in the insulating regime this quasithermal paradigm breaks down with relaxation toward a nonthermal state with a complicated electronic distribution as a function of momentum. We characterize the behavior by studying changes in the energy, photoemission response, and electronic distribution as functions of time. This relaxation may be observable qualitatively on short enough time scales that the electrons behave like an isolated system not in contact with additional degrees of freedom which would act as a thermal bath, especially when using strong driving fields and studying materials whose physics may manifest the effects of correlations.

  5. NEW STRONG-LINE ABUNDANCE DIAGNOSTICS FOR H II REGIONS: EFFECTS OF κ-DISTRIBUTED ELECTRON ENERGIES AND NEW ATOMIC DATA

    Energy Technology Data Exchange (ETDEWEB)

    Dopita, Michael A.; Sutherland, Ralph S.; Nicholls, David C.; Kewley, Lisa J.; Vogt, Frédéric P. A., E-mail: Michael.Dopita@anu.edu.au [Research School of Astronomy and Astrophysics, Australian National University, Cotter Rd., Weston ACT 2611 (Australia)

    2013-09-01

    Recently, Nicholls et al., inspired by in situ observations of solar system astrophysical plasmas, suggested that the electrons in H II regions are characterized by a κ-distribution of energies rather than a simple Maxwell-Boltzmann distribution. Here, we have collected together new atomic data within a modified photoionization code to explore the effects of both the new atomic data and the κ-distribution on the strong-line techniques used to determine chemical abundances in H II regions. By comparing the recombination temperatures (T {sub rec}) with the forbidden line temperatures (T {sub FL}), we conclude that κ ∼ 20. While representing only a mild deviation from equilibrium, this result is sufficient to strongly influence abundances determined using methods that depend on measurements of the electron temperature from forbidden lines. We present a number of new emission line ratio diagnostics that cleanly separate the two parameters determining the optical spectrum of H II regions—the ionization parameter q or U and the chemical abundance, 12+log(O/H). An automated code to extract these parameters is presented. Using the homogeneous data set from van Zee et al., we find self-consistent results between all of these different diagnostics. The systematic errors between different line ratio diagnostics are much smaller than those found in the earlier strong-line work. Overall, the effect of the κ-distribution on the strong-line abundances derived solely on the basis of theoretical models is rather small.

  6. Design Features of a Planar Hybrid/Permanent Magnet Strong Focusing Undulator for Free Electron Laser (FEL) And Synchrotron Radiation (SR) Applications

    Energy Technology Data Exchange (ETDEWEB)

    Tatchyn, Roman; /SLAC

    2011-09-09

    Insertion devices for Angstrom-wavelength Free Electron Laser (FEL) amplifiers driven by multi-GeV electron beams generally require distributed focusing substantially stronger than their own natural focusing fields. Over the last several years a wide variety of focusing schemes and configurations have been proposed for undulators of this class, ranging from conventional current-driven quadrupoles external to the undulator magnets to permanent magnet (PM) lattices inserted into the insertion device gap. In this paper we present design studies of a flexible high-field hybrid/PM undulator with strong superimposed planar PM focusing proposed for a 1.5 Angstrom Linac Coherent Light Source (LCLS) driven by an electron beam with a 1 mm-mr normalized emittance. Attainable field parameters, tuning modes, and potential applications of the proposed structure are discussed.

  7. Electron drift velocity in SF{sub 6} in strong electric fields determined from rf breakdown curves

    Energy Technology Data Exchange (ETDEWEB)

    Lisovskiy, V; Yegorenkov, V [Department of Physics and Technology, Kharkov National University, Svobody sq.4, Kharkov 61077 (Ukraine); Booth, J-P [Laboratoire de Physique des Plasmas, Ecole Polytechnique, Palaiseau 91128 (France); Landry, K [Unaxis Displays Division France SAS, 5, Rue Leon Blum, Palaiseau 91120 (France); Douai, D [Physical Sciences Division, Institute for Magnetic Fusion Research, CEA Centre de Cadarache, F-13108 Saint Paul lez Durance Cedex (France); Cassagne, V, E-mail: lisovskiy@yahoo.co [Developpement Photovoltaique Couches Minces, Total, 2, place Jean Millier, La Defense 6, 92400 Courbevoie (France)

    2010-09-29

    This paper presents measurements of the electron drift velocity V{sub dr} in SF{sub 6} gas for high reduced electric fields (E/N = 330-5655 Td (1 Td = 10{sup -17} V cm{sup 2})). The drift velocities were obtained using the method of Lisovskiy and Yegorenkov (1998 J. Phys. D: Appl. Phys. 31 3349) based on the determination of the pressure and voltage of the turning points of rf capacitive discharge breakdown curves for a range of electrode spacings. The V{sub dr} values thus obtained were in good agreement with those calculated from the cross-sections of Phelps and Van Brunt (1988 J. Appl. Phys. 64 4269) using the BOLSIG code. The validity of the Lisovskiy-Yegorenkov method is discussed and we show that it is applicable over the entire E/N range where rf discharge ignition at breakdown occurs for rf frequencies of 13.56 MHz or above.

  8. Rare earth monopnictides and monochalcogenides from first principles: towards an electronic phase diagram of strongly correlated materials

    DEFF Research Database (Denmark)

    Petit, Leon; Tyer, R.; Szotek, Z.

    2010-01-01

    calculated to within ~1.5% of the experimental values, and its ability to describe localization phenomena in solids, makes it a competitive atomistic simulation approach in the search for and design of new materials with specific physical properties and possible technological applications....... and exhibiting valency transitions brought about by a complex interplay between ligand chemistry and lanthanide contraction. The calculations exploit the combined effect of a first-principles methodology, which can adequately describe the dual character of electrons, itinerant versus localized, and high......-throughput computing made possible by the increasing available computational power. Our findings, including the predicted 'intermediate valent' compounds SmO and TmSe, are in excellent overall agreement with the available experimental data. The accuracy of the approach, proven e.g. through the lattice parameters...

  9. Generation of strong electromagnetic power at 35 GHz from the interaction of a resonant cavity with a relativistic electron beam generated by a free electron laser

    International Nuclear Information System (INIS)

    Lefevre, Thibaut

    2000-01-01

    The next generation of electron-positron linear colliders must reach the TeV energy range. For this, one requires an adequate RF power source to feed the accelerating cavities of the collider. One way to generate this source is to use the Two Beam Accelerator concept in which the RF power is produced in resonant cavities driven by an intense bunched beam. In this thesis, I present the experimental results obtained at the CEA/CESTA using an electron beam generated by an induction linac. First, some studies were performed with the LELIA induction linac (2.2 MeV, 1 kA, 80 ns) using a Free Electron Laser (FEL) as a buncher at 35 GHz. A second part relates the experiment made with the PIVAIR induction linac (7 MeV, 1 kA, 80 ns) in order to measure the RF power extracted from a resonant cavity at 35 GHz, which is driven by the bunches produced in the FEL. One can also find a simple theoretical modeling of the beam-cavity interaction, and the numerical results dealing with the design of the cavity we tested. (author) [fr

  10. Effect of strong correlations on the high energy anomaly in hole- and electron-doped high-T{sub c} superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Moritz, B; Johnston, S; Greven, M; Shen, Z-X; Devereaux, T P [Stanford Institute for Materials and Energy Science, SLAC National Accelerator Laboratory and Stanford University, Stanford, CA 94305 (United States); Schmitt, F; Meevasana, W; Motoyama, E M [Geballe Laboratory for Advanced Materials, Stanford University, Stanford, CA 94305 (United States); Lu, D H [Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA 94025 (United States); Kim, C [Institute of Physics and Applied Physics, Yonsei University, Seoul 120-749 (Korea, Republic of); Scalettar, R T [Physics Department, University of California-Davis, Davis, CA 95616 (United States)], E-mail: moritzb@slac.stanford.edu

    2009-09-15

    Recently, angle-resolved photoemission spectroscopy (ARPES) has been used to highlight an anomalously large band renormalization at high binding energies in cuprate superconductors: the high energy 'waterfall' or high energy anomaly (HEA). This paper demonstrates, using a combination of new ARPES measurements and quantum Monte Carlo simulations, that the HEA is not simply the by-product of matrix element effects, but rather represents a cross-over from a quasi-particle band at low binding energies near the Fermi level to valence bands at higher binding energy, assumed to be of strong oxygen character, in both hole- and electron-doped cuprates. While photoemission matrix elements clearly play a role in changing the aesthetic appearance of the band dispersion, i.e. the 'waterfall'-like behavior, they provide an inadequate description for the physics that underlies the strong band renormalization giving rise to the HEA. Model calculations of the single-band Hubbard Hamiltonian showcase the role played by correlations in the formation of the HEA and uncover significant differences in the HEA energy scale for hole- and electron-doped cuprates. In addition, this approach properly captures the transfer of spectral weight accompanying both hole and electron doping in a correlated material and provides a unifying description of the HEA across both sides of the cuprate phase diagram.

  11. Control rod withdrawal monitoring device

    International Nuclear Information System (INIS)

    Ebisuya, Mitsuo.

    1984-01-01

    Purpose: To prevent the power ramp even if a plurality of control rods are subjected to withdrawal operation at a time, by reducing the reactivity applied to the reactor. Constitution: The control rod withdrawal monitoring device is adapted to monitor and control the withdrawal of the control rods depending on the reactor power and the monitoring region thereof is divided into a control rod group monitoring region a transition region and a control group monitoring not interfere region. In a case if the distance between a plurality of control rods for which the withdrawal positions are selected is less than a limiting value, the coordinate for the control rods, distance between the control rods and that the control rod distance is shorter are displayed on a display panel, and the withdrawal for the control rods are blocked. Accordingly, even if a plurality of control rods are subjected successively to the withdrawal operation contrary to the control rod withdrawal sequence upon high power operation of the reactor, the power ramp can be prevented. (Kawakami, Y.)

  12. Theoretical analysis of the multiple resonances for many-level spin systems. The four-level spin system of s electron ions subjected to strong microwave fields

    International Nuclear Information System (INIS)

    Popescu, F.F.; Marica, F.

    1994-01-01

    The analytic steady state solutions of master equation for the density matrix of a multilevel spin system in dilute paramagnetic crystals at high temperature, subjected to strong microwave fields, are discussed. These solutions enable to obtain the populations of the levels, and the microwave powers absorbed or emitted by the crystal, in the presence of one, two or more microwave fields. A detailed theoretical study of the maser effects for s electron ions with nuclear spin one-half is carried out. In the case of three frequency correlated strong fields, when 'the spectroscopic' bridge conditions are fulfilled, sensitive detections, or high efficient generations of microwaves of frequency higher than those of the pumping fields are predicted. (author) 16 figs., 16 refs

  13. Exact ground-state correlation functions of one-dimenisonal strongly correlated electron models with resonating-valence-bond ground state

    International Nuclear Information System (INIS)

    Yamanaka, Masanori; Honjo, Shinsuke; Kohmoto, Mahito

    1996-01-01

    We investigate one-dimensional strongly correlated electron models which have the resonating-valence-bond state as the exact ground state. The correlation functions are evaluated exactly using the transfer matrix method for the geometric representations of the valence-bond states. In this method, we only treat matrices with small dimensions. This enables us to give analytical results. It is shown that the correlation functions decay exponentially with distance. The result suggests that there is a finite excitation gap, and that the ground state is insulating. Since the corresponding noninteracting systems may be insulating or metallic, we can say that the gap originates from strong correlation. The persistent currents of the present models are also investigated and found to be exactly vanishing

  14. Degradation of AlGaN/GaN High Electron Mobility Transistors with Different AlGaN Layer Thicknesses under Strong Electric Field

    International Nuclear Information System (INIS)

    Ling, Yang; Yue, Hao; Xiao-Hua, Ma; Jing-Jing, Ma; Cheng, Zhu

    2010-01-01

    The degradation of AlGaN/GaN high electron mobility transistors (HEMTs) has a close relationship with a model of traps in AlGaN barriers as a result of high electric field. We mainly discuss the impacts of strong electrical field on the AlGaN barrier thickness of AlGaN/GaN HEMTs. It is found that the device with a thin AlGaN barrier layer is more easily degraded. We study the degradation of four parameters, i.e. the gate series resistance R Gate , channel resistance R channel , gate current I G,off at V GS = −5 and V DS = 0.1 V, and drain current I D,max at V GS = 2 and V DS = 5 V. In addition, the degradation mechanisms of the device electrical parameters are also investigated in detail. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  15. Electron gas interacting in a metal, submitted to a strong magnetic field; Gas de eletrons interagentes num metal, sujeito a um campo magnetico forte

    Energy Technology Data Exchange (ETDEWEB)

    Alcaraz, Francisco Castilho

    1977-07-01

    Using the propagator's technique in the grand ensemble developed by Montroll and Ward we investigate the magnetic properties of an interacting electron gas in a strong magnetic field. The free propagator properly constructed shows that the spin paramagnetism does not have a term with strong temperature dependence, contrary to the result of Isihara. Considering the electron density to be constant, the dHVA oscillations in the magnetic susceptibility and sound velocity, considering the effects of first exchange interactions, show only one phase in agreement with experimental result, while Ichimura and Isihara obtained two phases differing by {pi}/2. The effects of first order exchange interactions in the dHVA oscillations of the magnetic susceptibility and sound velocity give rise to an exponential factor in the amplitudes of oscillator (Dingle factor), being the Dingle temperature linearly dependent of the Fermi velocity. The calculations of the ring diagram contribution to the grand partition function, show that the approximation used by Isihara for this calculations is not good and the dHVA oscillations of the contributions from the ring diagrams for the grand partition function have a phase differing by {pi}/2 from that obtained by Isihara. (author)

  16. Electron gas interacting in a metal, submitted to a strong magnetic field; Gas de eletrons interagentes num metal, sujeito a um campo magnetico forte

    Energy Technology Data Exchange (ETDEWEB)

    Alcaraz, Francisco Castilho

    1977-07-01

    Using the propagator's technique in the grand ensemble developed by Montroll and Ward we investigate the magnetic properties of an interacting electron gas in a strong magnetic field. The free propagator properly constructed shows that the spin paramagnetism does not have a term with strong temperature dependence, contrary to the result of Isihara. Considering the electron density to be constant, the dHVA oscillations in the magnetic susceptibility and sound velocity, considering the effects of first exchange interactions, show only one phase in agreement with experimental result, while Ichimura and Isihara obtained two phases differing by {pi}/2. The effects of first order exchange interactions in the dHVA oscillations of the magnetic susceptibility and sound velocity give rise to an exponential factor in the amplitudes of oscillator (Dingle factor), being the Dingle temperature linearly dependent of the Fermi velocity. The calculations of the ring diagram contribution to the grand partition function, show that the approximation used by Isihara for this calculations is not good and the dHVA oscillations of the contributions from the ring diagrams for the grand partition function have a phase differing by {pi}/2 from that obtained by Isihara. (author)

  17. Detailed investigation of thermal and electron transport properties in strongly correlated compound Ce6Pd12In5 and its nonmagnetic analog La6Pd12In5

    Science.gov (United States)

    Falkowski, M.; Krychowski, D.; Strydom, A. M.

    2016-11-01

    An in-depth study of thermal and electron transport properties including thermal conductivity κ(T), thermoelectric power S(T), and electrical resistivity ρ(T) of the heavy fermion Kondo lattice Ce6Pd12In5 and its nonmagnetic reference compound La6Pd12In5 is presented. The absolute κ(T) value of Ce6Pd12In5 is smaller that than of La6Pd12In5, which indicates that conduction electron-4f electron scattering has a large impact on the reduction of thermal conductivity. The isolated 4f electron contributions to the electrical resistivity ρ 4 f (T), electronic thermal resistivity displayed in the form W e l , 4 f (T) .T, and thermoelectric power S 4 f (T) reveal a low- and high-temperature -lnT behaviour characteristic of Kondo systems with strong crystal-electric field (CEF) interactions. The analysis of phonon scattering processes of lattice thermal conductivity κph(T) in (Ce, La)6Pd12In5 was performed over the whole accessible temperature range according to the Callaway model. In the scope of a theoretical approach based on the perturbation type calculation, we were able to describe our experimental data of ρ 4 f (T) and W e l , 4 f (T) .T by using the model incorporating simultaneously the Kondo effect in the presence of the CEF splitting, as it is foreseen in the framework of the Cornut-Coqblin and Bhattacharjee-Coqblin theory. Considering the fact that there are not many cases of similar studies at all, we also show the numerical calculations of temperature-dependent behaviour of spin-disorder resistivity ρs(T), magnetic resistivity ρ 4 f (T), and occupation number ⟨ N i ⟩ due to the various types of degeneracy of the ground state multiplet of Ce 3 + (J = 5/2).

  18. Caffeine Withdrawal and Dependence: A Convenience Survey Among Addiction Professionals.

    Science.gov (United States)

    Budney, Alan J; Brown, Pamela C; Griffiths, Roland R; Hughes, John R; Juliano, Laura M

    2013-06-01

    Caffeine withdrawal was included in the research appendix of the DSM-IV to encourage additional research to assist with determining its status for the next version of the manual. Caffeine dependence was not included because of a lack of empirical research at the time of publication. This study assessed the beliefs of addiction professionals about the clinical importance of caffeine withdrawal and dependence. A 6-item survey was developed and delivered electronically to the members of six professional organizations that focus on addiction. Open-ended comments were also solicited. Five hundred members responded. The majority (95%) thought that cessation of caffeine could produce a withdrawal syndrome, and that caffeine withdrawal can have clinical importance (73%); however, only half (48%) thought that caffeine withdrawal should be included in the Diagnostic and Statistical Manual of Mental Disorders (DSM). A majority (58%) believed that some people develop caffeine dependence; however, only 44% indicated that it should be in the DSM. Comments suggested that trepidation about inclusion of caffeine diagnoses was due to the concerns about the field of psychiatry being criticized for including common disorders with a relatively low clinical severity. Others, however, expressed an urgent need to take caffeine-related problems more seriously. The majority of addiction professionals believe that caffeine withdrawal and dependence disorders exist and are clinically important; however, these professionals are divided in whether caffeine withdrawal and dependence should be included in DSM. Wider dissemination of the extant literature on caffeine withdrawal and additional research on caffeine dependence will be needed to provide additional guidance to policymakers and healthcare workers.

  19. Single-step electron transfer on the nanometer scale: ultra-fast charge shift in strongly coupled zinc porphyrin-gold porphyrin dyads.

    Science.gov (United States)

    Fortage, Jérôme; Boixel, Julien; Blart, Errol; Hammarström, Leif; Becker, Hans Christian; Odobel, Fabrice

    2008-01-01

    The synthesis, electrochemical properties, and photoinduced electron transfer processes of a series of three novel zinc(II)-gold(III) bisporphyrin dyads (ZnP--S--AuP(+)) are described. The systems studied consist of two trisaryl porphyrins connected directly in the meso position via an alkyne unit to tert-(phenylenethynylene) or penta(phenylenethynylene) spacers. In these dyads, the estimated center to center interporphyrin separation distance varies from 32 to 45 A. The absorption, emission, and electrochemical data indicate that there are strong electronic interactions between the linked elements, thanks to the direct attachment of the spacer on the porphyrin ring through the alkyne unit. At room temperature in toluene, light excitation of the zinc porphyrin results in almost quantitative formation of the charge shifted state (.+)ZnP--S--AuP(.), whose lifetime is in the order of hundreds of picoseconds. In this solvent, the charge-separated state decays to the ground state through the intermediate population of the zinc porphyrin triplet excited state. Excitation of the gold porphyrin leads instead to rapid energy transfer to the triplet ZnP. In dichloromethane the charge shift reactions are even faster, with time constants down to 2 ps, and may be induced also by excitation of the gold porphyrin. In this latter solvent, the longest charge-shifted lifetime (tau=2.3 ns) was obtained with the penta-(phenylenethynylene) spacer. The charge shift reactions are discussed in terms of bridge-mediated super-exchange mechanisms as electron or hole transfer. These new bis-porphyrin arrays, with strong electronic coupling, represent interesting molecular systems in which extremely fast and efficient long-range photoinduced charge shift occurs over a long distance. The rate constants are two to three orders of magnitude larger than for corresponding ZnP--AuP(+) dyads linked via meso-phenyl groups to oligo-phenyleneethynylene spacers. This study demonstrates the critical

  20. Atomic and electronic structure of trilayer graphene/SiC(0001): Evidence of Strong Dependence on Stacking Sequence and charge transfer.

    Science.gov (United States)

    Pierucci, Debora; Brumme, Thomas; Girard, Jean-Christophe; Calandra, Matteo; Silly, Mathieu G; Sirotti, Fausto; Barbier, Antoine; Mauri, Francesco; Ouerghi, Abdelkarim

    2016-09-15

    The transport properties of few-layer graphene are the directly result of a peculiar band structure near the Dirac point. Here, for epitaxial graphene grown on SiC, we determine the effect of charge transfer from the SiC substrate on the local density of states (LDOS) of trilayer graphene using scaning tunneling microscopy/spectroscopy and angle resolved photoemission spectroscopy (ARPES). Different spectra are observed and are attributed to the existence of two stable polytypes of trilayer: Bernal (ABA) and rhomboedreal (ABC) staking. Their electronic properties strongly depend on the charge transfer from the substrate. We show that the LDOS of ABC stacking shows an additional peak located above the Dirac point in comparison with the LDOS of ABA stacking. The observed LDOS features, reflecting the underlying symmetry of the two polytypes, were reproduced by explicit calculations within density functional theory (DFT) including the charge transfer from the substrate. These findings demonstrate the pronounced effect of stacking order and charge transfer on the electronic structure of trilayer or few layer graphene. Our approach represents a significant step toward understand the electronic properties of graphene layer under electrical field.

  1. Strongly disordered superconductors

    International Nuclear Information System (INIS)

    Muttalib, K.A.

    1982-01-01

    We examine some universal effects of strong non-magnetic disorder on the electron-phonon and electron-electron interactions in a superconductor. In particular we explicitly take into account the effect of slow diffusion of electrons in a disordered medium by working in an exact impurity eigenstate representation. We find that the normal diffusion of electrons characterized by a constant diffusion coefficient does not lead to any significant correction to the electron-phonon or the effective electron-electron interactions in a superconductor. We then consider sufficiently strong disorder where Anderson localization of electrons becomes important and determine the effect of localization on the electron-electron interactions. We find that due to localization, the diffusion of electrons becomes anomalous in the sense that the diffusion coefficient becomes scale dependent. This results in an increase in the effective electron-electron interaction with increasing disorder. We propose that this provides a natural explanation for the unusual sensitivity of the transition temperature T/sub c/ of the high T/sub c/ superconductors (T/sub c/ > 10 0 K) to damage effects

  2. Understanding the electric field control of the electronic and optical properties of strongly-coupled multi-layered quantum dot molecules.

    Science.gov (United States)

    Usman, Muhammad

    2015-10-21

    Strongly-coupled quantum dot molecules (QDMs) are widely employed in the design of a variety of optoelectronic, photovoltaic, and quantum information devices. An efficient and optimized performance of these devices demands engineering of the electronic and optical properties of the underlying QDMs. The application of electric fields offers a way to realise such a control over the QDM characteristics for a desired device operation. We performed multi-million-atom atomistic tight-binding calculations to study the influence of electric fields on the electron and hole wave function confinements and symmetries, the ground-state transition energies, the band-gap wavelengths, and the optical transition modes. Electrical fields parallel (Ep) and anti-parallel (Ea) to the growth direction were investigated to provide a comprehensive guide for understanding the electric field effects. The strain-induced asymmetry of the hybridized electron states is found to be weak and can be balanced by applying a small Ea electric field, of the order of 1 kV cm(-1). The strong interdot couplings completely break down at large electric fields, leading to single QD states confined at the opposite edges of the QDM. This mimics a transformation from a type-I band structure to a type-II band structure for the QDMs, which is a critical requirement for the design of intermediate-band solar cells (IBSCs). The analysis of the field-dependent ground-state transition energies reveals that the QDM can be operated both as a high dipole moment device by applying large electric fields and as a high polarizability device under the application of small electric field magnitudes. The quantum confined Stark effect (QCSE) red shifts the band-gap wavelength to 1.3 μm at the 15 kV cm(-1) electric field; however the reduced electron-hole wave function overlaps lead to a decrease in the interband optical transition strengths by roughly three orders of magnitude. The study of the polarisation-resolved optical

  3. 75 FR 2894 - Withdrawal of Regulatory Guide 1.148

    Science.gov (United States)

    2010-01-19

    ... downloading through the NRC's public Web site under ``Regulatory Guides'' in the NRC's Electronic Reading Room at http://www.nrc.gov/reading-rm/doc-collections . Regulatory guides are also available for... NUCLEAR REGULATORY COMMISSION [NRC-2010-0013] Withdrawal of Regulatory Guide 1.148 AGENCY: Nuclear...

  4. 75 FR 70044 - Withdrawal of Regulatory Guide 1.39

    Science.gov (United States)

    2010-11-16

    ... downloading through the NRC's public Web site under ``Regulatory Guides'' in the NRC's Electronic Reading Room at http://www.nrc.gov/reading-rm/doollectionsc-c . Regulatory guides are also available for... NUCLEAR REGULATORY COMMISSION [NRC-2010-0354] Withdrawal of Regulatory Guide 1.39 AGENCY: Nuclear...

  5. Strongly Anisotropic Electronic Transport at Landau Level Filling Factor ν =9/2 and ν =5/2 under a Tilted Magnetic Field

    International Nuclear Information System (INIS)

    Pan, W.; Tsui, D.C.; Pan, W.; Du, R.R.; Du, R.R.; Stormer, H.L.; Pfeiffer, L.N.; Baldwin, K.W.; West, K.W.; Stormer, H.L.; Stormer, H.L.

    1999-01-01

    We have investigated the influence of an increasing in-plane magnetic field on the states of half filling of Landau levels (ν=11/2, 9/2, 7/2, thinspandthinsp 5/2) of a two-dimensional electron system. In the electrically anisotropic phase at ν=9/2 and 11/2 an in-plane magnetic field of ∼1 - 2 T overcomes its initial pinning to the crystal lattice and reorients this phase. In the initially isotropic phases at ν=5/2 and 7/2 an in-plane magnetic field induces a strong electrical anisotropy. In all cases, for high in-plane fields the high-resistance axis is parallel to the direction of the in-plane field. copyright 1999 The American Physical Society

  6. Warm Dense Matter and Strongly Coupled Plasmas Created by Intense Heavy Ion Beams and XUV-Free Electron Laser: An Overview of Spectroscopic Methods

    Energy Technology Data Exchange (ETDEWEB)

    Rosmej, F B [University of Provence et CNRS, Centre St. Jerome, PIIM-DGP, case 232, 13397 Marseille Cedex 20 (France); Lee, R W [Lawrence Livermore National Laboratory, Livermore, CA (United States); Riley, D [Queens University of Belfast, University Road, Belfast BT7 1NN (United Kingdom); Meyer-ter-Vehn, J [Max-Planck Institute for Quantum Optics, 85748 Garching (Germany); Krenz, A [Max-Planck Institute for Quantum Optics, 85748 Garching (Germany); Tschentscher, T [HASYLAB at DESY, Nothkestrasse 85, 22607 Hamburg (Germany); Tauschwitz, An [University of Frankfurt, Institute of Theoretical Physics, Frankfurt (Germany); Tauschwitz, A [Gesellschaft fuer Schwerionenforschung GSI, Planckstr. 1, 64291 Darmstadt (Germany); Lisitsa, V S [Russian Research Center Kurchatov, 123182 Moscow (Russian Federation); Faenov, A Ya [VNIIFTRI, Multi Charged Ion Spectra Data Center, 141570 Mendeleevo (Russian Federation)

    2007-06-15

    High density plasma physics, radiation emission/scattering and related atomic physics, spectroscopy and diagnostics are going to make large steps forward due to new experimental facilities providing beams of intense heavy ions and X/XUV free electron laser radiation. These facilities are currently being established at GSI-Darmstadt and DESY-Hamburg in Germany to access new and complementary parameter regimes for basic research which have never been obtained in laboratories so far: homogenous benchmark samples near solid density and temperatures from eV up to keV. This will provide important impact to many disciplines like astrophysics, atomic physics in dense environments, dense and strongly coupled plasma effects, radiation emission, equation of state. The spectroscopic analysis of the radiation emission plays a key role in this research to investigate the dynamics of electric fields in multi-particle coupled Coulomb systems and the modification of plasma statistics.

  7. Electron-positron pairs creation in the field of two strong counterpropagating laser beams and the nonlocality of the photon-photon interaction

    International Nuclear Information System (INIS)

    Gainutdinov, R.Kh.; Khamadeev, M.A.; Mutygullina, A.A.

    2010-01-01

    Complete text of publication follows. We discuss various approaches to problem of the electron-positron pair creation in the strong external field. Special interest presents the circuit, in which the interaction of two strong counterpropagating laser beams in vacuum is considered. For the calculation of the probability of the creation the following formula is usually applied: W = 2Im(L (E-H) (ρ L )) = 2m 4 /(2π) 3 ρ L 2 Σ n=1 -∞ 1/n 2 e -nπ /ρ L where ρ L = E L / E cr and E cr = m 2 /e = 1.3 x 10 16 V/cm is the Schwinger field limit. However this expression was obtained even in pioneer works dedicated to vacuum nonlinearity and it based on some approximations. Attempt of the strict analysis has been made in work by introducing the nonlocal form-factor into the Lagrangian. But, as it is well known, such procedure leads to the loss of Lorenz invariance or unitarity. We show that the formalism of generalized quantum dynamic (GQD) opens new opportunities to solve such problems. We show also how it can be made proceeding from nonlocal interaction operator obtained earlier within the framework of the formalism of GQD. Acknowledgements. This work was supported by the Grant of Federal Agency on Education, Russia (Contract number 02.740.11.0428) and by the Grant of Russian President No. NSh 2965.2008.2.

  8. Strong band edge luminescence from InN films grown on Si substrates by electron cyclotron resonance-assisted molecular beam epitaxy

    International Nuclear Information System (INIS)

    Yodo, Tokuo; Yona, Hiroaki; Ando, Hironori; Nosei, Daiki; Harada, Yoshiyuki

    2002-01-01

    We observed strong band edge luminescence at 8.5-200 K from 200-880 nm thick InN films grown on 10 nm thick InN buffer layers on Si(001) and Si(111) substrates by electron cyclotron resonance-assisted molecular beam epitaxy. The InN film on the Si(001) substrate exhibited strong band edge photoluminescence (PL) emission at 1.814 eV at 8.5 K, tentatively assigned as donor to acceptor pair [DAP (α-InN)] emission from wurtzite-InN (α-InN) crystal grains, while those on Si(111) showed other stronger band edge PL emissions at 1.880, 2.081 and 2.156 eV, tentatively assigned as donor bound exciton [D 0 X(α-InN)] from α-InN grains, DAP (β-InN) and D 0 X (β-InN) emissions from zinc blende-InN (β-InN) grains, respectively

  9. Alcohol Withdrawal Mimicking Organophosphate Poisoning

    Directory of Open Access Journals (Sweden)

    Nezihat Rana Disel

    2014-02-01

    Full Text Available Organophosphates, which can cause occupational poisoning due to inappropriate personal protective measures, are widely used insecticides in agricultural regions of southern Turkey. Therefore, the classical clinical findings of this cholinergic poisoning are myosis, excessive secretions, bradicardia and fasciculations are easy to be recognized by local medical stuff. Diseases and conditions related to alcoholism such as mental and social impairments, coma, toxicity, withdrawal, and delirium are frequent causes of emergency visits of chronic alcoholic patients. Here we present a case diagnosed and treated as organophosphate poisoning although it was an alcohol withdrawal in the beginning and became delirium tremens, due to similar symptoms.

  10. Effects of multiple electronic shells on strong-field multiphoton ionization and high-order harmonic generation of diatomic molecules with arbitrary orientation: An all-electron time-dependent density-functional approach

    International Nuclear Information System (INIS)

    Telnov, Dmitry A.; Chu, S.-I

    2009-01-01

    We present a time-dependent density-functional theory approach with proper long-range potential for an ab initio study of the effect of correlated multielectron responses on the multiphoton ionization (MPI) and high-order harmonic generation (HHG) of diatomic molecules N 2 and F 2 in intense short laser pulse fields with arbitrary molecular orientation. We show that the contributions of inner molecular orbitals to the total MPI probability can be sufficiently large or even dominant over the highest-occupied molecular orbital, depending on detailed electronic structure and symmetry, laser field intensity, and orientation angle. The multielectron effects in HHG are also very important. They are responsible for enhanced HHG at some orientations of the molecular axis. Even strongly bound electrons may have a significant influence on the HHG process.

  11. Water withdrawals in Florida, 2012

    Science.gov (United States)

    Marella, Richard L.

    2015-09-01

    In 2012, the total amount of water withdrawn in Florida was estimated to be 14,237 million gallons per day (Mgal/d). Saline water accounted for 7,855 Mgal/d (55 percent), and freshwater accounted for 6,383 Mgal/d (45 percent). Groundwater accounted for 4,167 Mgal/d (65 percent) of freshwater withdrawals, and surface water accounted for the remaining 2,216 Mgal/d (35 percent). Surface water accounted for nearly all (99.9 percent) saline-water withdrawals. Freshwater withdrawals were greatest in Palm Beach County (682 Mgal/d), and saline-water withdrawals were greatest in Pasco County (1,822 Mgal/d). Fresh groundwater provided drinking water (through either public supply or private domestic wells) for 17.699 million residents (93 percent of Florida’s population), and fresh surface water provided drinking water for 1.375 million residents (7 percent). The statewide public-supply gross per capita water use for 2012 was estimated at 136 gallons per day.

  12. Buprenorphine for managing opioid withdrawal.

    Science.gov (United States)

    Gowing, Linda; Ali, Robert; White, Jason M; Mbewe, Dalitso

    2017-02-21

    Managed withdrawal is a necessary step prior to drug-free treatment or as the endpoint of substitution treatment. To assess the effects of buprenorphine versus tapered doses of methadone, alpha 2 -adrenergic agonists, symptomatic medications or placebo, or different buprenorphine regimens for managing opioid withdrawal, in terms of the intensity of the withdrawal syndrome experienced, duration and completion of treatment, and adverse effects. We searched the Cochrane Central Register of Controlled Trials (CENTRAL, Issue 11, 2016), MEDLINE (1946 to December week 1, 2016), Embase (to 22 December 2016), PsycINFO (1806 to December week 3, 2016), and the Web of Science (to 22 December 2016) and handsearched the reference lists of articles. Randomised controlled trials of interventions using buprenorphine to modify the signs and symptoms of withdrawal in participants who were primarily opioid dependent. Comparison interventions involved reducing doses of methadone, alpha 2 -adrenergic agonists (clonidine or lofexidine), symptomatic medications or placebo, and different buprenorphine-based regimens. We used standard methodological procedures expected by Cochrane. We included 27 studies involving 3048 participants. The main comparators were clonidine or lofexidine (14 studies). Six studies compared buprenorphine versus methadone, and seven compared different rates of buprenorphine dose reduction. We assessed 12 studies as being at high risk of bias in at least one of seven domains of methodological quality. Six of these studies compared buprenorphine with clonidine or lofexidine and two with methadone; the other four studies compared different rates of buprenorphine dose reduction.For the comparison of buprenorphine and methadone in tapered doses, meta-analysis was not possible for the outcomes of intensity of withdrawal or adverse effects. However, information reported by the individual studies was suggestive of buprenorphine and methadone having similar capacity to

  13. Prediction of withdrawal symptoms during opioid detoxification

    NARCIS (Netherlands)

    Dijkstra, Boukje A G; Krabbe, Paul F M; De Jong, Cor A J; van der Staak, Cees P F

    2008-01-01

    OBJECTIVE: The severity of self-reported withdrawal symptoms varies during detoxification of opioid-dependent patients. The aim of this study is to identify subgroups of withdrawal symptoms within the detoxification trajectory and to predict the severity of withdrawal symptoms on the basis of

  14. The benzodiazepine withdrawal syndrome and its management.

    OpenAIRE

    Onyett, S R

    1989-01-01

    The literature on benzodiazepine dependence and withdrawal is reviewed with an emphasis on social and psychological considerations. The problems of when to prescribe, identifying withdrawal symptoms, effective communication with the patient, the structure of withdrawal programmes, and the use of drugs, psychological approaches and other services are discussed.

  15. Prediction of withdrawal symptoms during opioid detoxification

    NARCIS (Netherlands)

    Dijkstra, B.A.G.; Krabbe, P.F.M.; Jong, C.A.J. de; Staak, C.P.F. van der

    2008-01-01

    Objective: The severity of self-reported withdrawal symptoms varies during detoxification of opioid-dependent patients. The aim of this study is to identify subgroups of withdrawal symptoms within the detoxification trajectory and to predict the severity of withdrawal symptoms on the basis of

  16. Strong coupling between bi-dimensional electron gas and nitrogen localized states in heavily doped GaAs1-xN x structures

    International Nuclear Information System (INIS)

    Hamdouni, A.; Bousbih, F.; Ben Bouzid, S.; Oueslati, M.; Chtourou, R.; Harmand, J.C.

    2005-01-01

    We report a low-temperature photoluminescence spectra (LTPL) of GaAs 1-x N x layers and two-dimension electron gas (2DEG) GaAs 1-x N x /AlGaAs modulation doped heterostructure grown on GaAs substrates by molecular beam epitaxy (MBE) with low nitrogen content [N] = 2 x 10 18 cm -3 . At low temperature, PL spectra of GaAs 1-x N x layers are governed by several features associate to the excitons bound to nitrogen complexes, these features disappear in (2DEG) GaAs 1-x N x /AlGaAs modulation doped heterostructure and the PL peak energy decrease with the laser power excitation. This effect is explained by the strongly coupling of the (2DEG) fundamental state with the nitrogen localized states. An activated energy of about 55 meV is deduced by photoluminescence measurements in the 10-300 K range for a laser power excitation P = 6 W/cm 2

  17. Coupled cluster theory of strongly correlated spin- and electron-lattice systems: an illustration via a model exhibiting competition between magnetic order and dimerization

    International Nuclear Information System (INIS)

    Bishop, Raymond F; Krueger, Sven E

    2003-01-01

    The coupled cluster method (CCM) of microscopic quantum many-body theory has become an ab initio method of first choice in quantum chemistry and many fields of nuclear, subnuclear and condensed matter physics, when results of high accuracy are required. In recent years it has begun to be applied with equal success to strongly correlated systems of electrons or quantum spins defined on a regular spatial lattice. One regularly finds that the CCM is able to describe accurately the various zero-temperature phases and the quantum phase transitions between them, even when frustration is present and other methods such as quantum Monte Carlo often fail. We illustrate the use and powerfulness of the method here by applying it to a square-lattice spin-half Heisenberg model where frustration is introduced by competing nearest neighbour bonds. The model exhibits the physically interesting phenomenon of competition between magnetic order and dimerization. Results obtained for the model with the CCM are compared with those found from spin-wave theory and from extrapolating the results of exact diagonalizations of small lattices. We show that the CCM is essentially unique among available methods in being able both to describe accurately all phases of this complex model and to provide accurate predictions of the various phase boundaries and the order of the corresponding transitions

  18. Amorphization-induced strong localization of electronic states in CsPbBr3 and CsPbCl3 studied by optical absorption measurements

    Science.gov (United States)

    Kondo, S.; Sakai, T.; Tanaka, H.; Saito, T.

    1998-11-01

    Optical absorption spectra of amorphous CsPbX3 films (X=Br,Cl) are characterized by two Gaussian bands near the fundamental edge, with the optical energy gap largely blueshifted and the absorption intensity strongly reduced as compared with the crystalline films. The peak energies of the bands are close to those of the A and C bands of Pb-doped alkali halides. The spectral features are discussed in terms of a molecular orbital theory based on a quasicomplex Pb2+(X-)6 model similar to the complex model for the doped alkali halides. It is shown that not only Pb2+ 6s and 6p extended states near the band edges but also X- p states contributing to upper valence bands are localized by amorphization. The transitions from the localized Pb2+ 6s to 6p states produce the spin-orbit allowed 3P1 and dipole allowed 1P1 states responsible for the two Gaussians. The localized X- p states lie deeper in energy than the localized Pb2+ 6s state and only contribute to higher-energy absorption above the Gaussian bands, giving the reason for the reduced absorption near the fundamental edge. The blueshift of the optical energy gap is attributed to the disappearance of k dispersions for these one-electron states.

  19. <strong>Mini-project>

    DEFF Research Database (Denmark)

    Katajainen, Jyrki

    2008-01-01

    In this project the goal is to develop the safe * family of containers for the CPH STL. The containers to be developed should be safer and more reliable than any of the existing implementations. A special focus should be put on strong exception safety since none of the existing prototypes available...

  20. Strong interactions

    International Nuclear Information System (INIS)

    Froissart, Marcel

    1976-01-01

    Strong interactions are introduced by their more obvious aspect: nuclear forces. In hadron family, the nucleon octet, OMEGA - decuplet, and quark triply are successively considered. Pion wave having been put at the origin of nuclear forces, low energy phenomena are described, the force being explained as an exchange of structure corresponding to a Regge trajectory in a variable rotating state instead of the exchange of a well defined particle. At high energies the concepts of pomeron, parton and stratons are introduced, pionization and fragmentation are briefly differentiated [fr

  1. Withdrawal: Expanding a Key Addiction Construct.

    Science.gov (United States)

    Piper, Megan E

    2015-12-01

    Withdrawal is an essential component of classical addiction theory; it is a vital manifestation of dependence and motivates relapse. However, the traditional conceptualization of withdrawal as a cohesive collection of symptoms that emerge during drug deprivation and decline with either the passage of time or reinstatement of drug use, may be inadequate to explain scientific findings or fit with modern theories of addiction. This article expands the current understanding of tobacco withdrawal by examining: (1) withdrawal variability; (2) underlying causes of withdrawal variability, including biological and person factors, environmental influences, and the influence of highly routinized behavioral patterns; (3) new withdrawal symptoms that allow for enhanced characterization of the withdrawal experience; and (4) withdrawal-related cognitive processes. These topics provide guidance regarding the optimal assessment of withdrawal and illustrate the potential impact modern withdrawal conceptualization and assessment could have on identifying treatment targets. © The Author 2015. Published by Oxford University Press on behalf of the Society for Research on Nicotine and Tobacco. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  2. It's self defense: how perceived discrimination promotes employee withdrawal.

    Science.gov (United States)

    Volpone, Sabrina D; Avery, Derek R

    2013-10-01

    Integrating theory on stress, stigma, and coping, the present study sheds light on how employees react to perceived discrimination (PD) in the workplace. Using three national samples, we found that PD based on race, sex, age, family obligation, and sexual orientation related to physical withdrawal (i.e., lateness, absenteeism,and intent to quit) indirectly through psychological withdrawal (i.e., burnout and engagement) such that PD corresponded in less engagement and more burnout, which related to increased lateness, absenteeism, and intent to quit [corrected].Further, these indirect relationships were moderated by employees' coping mechanisms with those who were more apt to change the situation or to avoid the stressor exhibiting weaker relationships between PD and psychological withdrawal. Though each of these studies is cross-sectional in nature and therefore cannot provide strong evidence of causal ordering of the variables in our model, the replication and extension of results over three databases and multiple forms of discrimination, coping, psychological, and physical withdrawal demonstrates that understanding the relationships explored in these studies can aid researchers and practitioners in enhancing employee quality of life and productivity.

  3. Plasmons in strong superconductors

    International Nuclear Information System (INIS)

    Baldo, M.; Ducoin, C.

    2011-01-01

    We present a study of the possible plasmon excitations that can occur in systems where strong superconductivity is present. In these systems the plasmon energy is comparable to or smaller than the pairing gap. As a prototype of these systems we consider the proton component of Neutron Star matter just below the crust when electron screening is not taken into account. For the realistic case we consider in detail the different aspects of the elementary excitations when the proton, electron components are considered within the Random-Phase Approximation generalized to the superfluid case, while the influence of the neutron component is considered only at qualitative level. Electron screening plays a major role in modifying the proton spectrum and spectral function. At the same time the electron plasmon is strongly modified and damped by the indirect coupling with the superfluid proton component, even at moderately low values of the gap. The excitation spectrum shows the interplay of the different components and their relevance for each excitation modes. The results are relevant for neutrino physics and thermodynamical processes in neutron stars. If electron screening is neglected, the spectral properties of the proton component show some resemblance with the physical situation in high-T c superconductors, and we briefly discuss similarities and differences in this connection. In a general prospect, the results of the study emphasize the role of Coulomb interaction in strong superconductors.

  4. Socially Anxious Smokers Experience Greater Negative Affect and Withdrawal during Self-Quit Attempts

    OpenAIRE

    Buckner, Julia D.; Langdon, Kirsten J.; Jeffries, Emily R.; Zvolensky, Michael J.

    2016-01-01

    Despite evidence of a strong and consistent relation between smoking and elevated social anxiety, strikingly little empirical work has identified mechanisms underlying the smoking-social anxiety link. Persons with elevated social anxiety may rely on smoking to cope with more severe nicotine withdrawal and post-quit negative mood states; yet, no known studies have investigated the relation of social anxiety to withdrawal severity. The current study examined the relation of social anxiety to po...

  5. Withdrawal: Plews and Laursen (2017).

    Science.gov (United States)

    2018-03-01

    We, the Editors and Publishers of the International Journal of Sports Physiology and Performance, have withdrawn the following article in whole: Plews, DJ, Laursen, PB. Training intensity distribution over a four-year cycle in Olympic champion rowers: different roads lead to Rio [version of record published online ahead of print September 27, 2017]. Int J Sports Physiol Perform. doi: 10.1123/ijspp.2017-0343 . The Editorial Office was contacted with the request to withdraw this article informing the Editor-in-Chief that the data in this article were not permissible to use due to undisclosed contractual obligations.

  6. Excitonic condensation of strongly correlated electrons: the case of Pr.sub.0.5./sub. Ca.sub.0.5./sub. CoO.sub.3./sub..

    Czech Academy of Sciences Publication Activity Database

    Kuneš, Jan; Augustinský, Pavel

    2014-01-01

    Roč. 90, č. 23 (2014), "235112-1"-"235112-5" ISSN 1098-0121 R&D Projects: GA ČR GA13-25251S Institutional support: RVO:68378271 Keywords : excitonic condensation * strongly correlated electrons * cobaltites Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.736, year: 2014

  7. Socially anxious smokers experience greater negative affect and withdrawal during self-quit attempts.

    Science.gov (United States)

    Buckner, Julia D; Langdon, Kirsten J; Jeffries, Emily R; Zvolensky, Michael J

    2016-04-01

    Despite evidence of a strong and consistent relation between smoking and elevated social anxiety, strikingly little empirical work has identified mechanisms underlying the smoking-social anxiety link. Persons with elevated social anxiety may rely on smoking to cope with more severe nicotine withdrawal and post-quit negative mood states; yet, no known studies have investigated the relation of social anxiety to withdrawal severity. The current study examined the relation of social anxiety to post-quit nicotine withdrawal severity among 51 (33.3% female, Mage = 34.6) community-recruited smokers during the first two weeks following an unaided (i.e., no treatment) cessation attempt. Ecological momentary assessment was used to collect multiple daily ratings of withdrawal and negative mood states. Baseline social anxiety was related to increases in negative affect during the monitoring period and remained significantly related to post-quit withdrawal after controlling for negative affect, gender, lapses, and substance use. Persons with elevated social anxiety experience more severe post-quit withdrawal symptoms and increases in negative affect during a cessation attempt and may therefore benefit from intervention and treatment strategies geared toward helping them learn to cope with withdrawal and negative affect to improve cessation rates among these vulnerable smokers.

  8. Many-polaron theory for superconductivity and charge-density waves in a strongly coupled electron-phonon system with quasi-two-dimensionality: An interpolation between the adiabatic limit and the inverse-adiabatic limit

    International Nuclear Information System (INIS)

    Nasu, K.

    1987-01-01

    The phase diagram of a two-dimensional N-site N-electron system (N>>1) with site-diagonal electron-phonon (e-ph) coupling is studied in the context of polaron theory, so as to clarify the competition between the superconducting (SC) state and the charge-density wave (CDW) state. The Fermi surface of noninteracting electrons is assumed to be a complete circle with no nesting-type instability in the case of weak e-ph coupling, so as to focus on such a strong coupling that even the standard ''strong-coupling theory'' for superconductivity breaks down. Phonon clouds moving with electrons as well as a frozen phonon are taken into account by a variational method, combined with a mean-field theory. It covers the whole region of three basic parameters characterizing the system: the intersite transfer energy of electron T, the e-ph coupling energy S, and the phonon energy ω. The resultant phase diagram is given in a triangular coordinate space spanned by T, S, and ω. In the adiabatic region ω >(T,S) near the ω vertex of the triangle, on the other hand, each electron becomes a small polaron, and the SC state is always more stable than the CDW state, because the retardation effect is absent

  9. 42 CFR 457.170 - Withdrawal process.

    Science.gov (United States)

    2010-10-01

    ... 42 Public Health 4 2010-10-01 2010-10-01 false Withdrawal process. 457.170 Section 457.170 Public... Plans for Child Health Insurance Programs and Outreach Strategies § 457.170 Withdrawal process. (a... amendment, or any portion of a proposed State plan or plan amendment, at any time during the review process...

  10. Perinatal risk factors and social withdrawal behaviour.

    Science.gov (United States)

    Guedeney, Antoine; Marchand-Martin, Laetitia; Cote, Sylvana J; Larroque, Béatrice

    2012-04-01

    The objectives of the study were (1) to assess prevalence of social withdrawal behaviour in infants aged 12 months included in the French Perinatal Risk Factor Study Eden; (2) To study the correlation between relational withdrawal and several perinatal and parental factors assessed in the EDEN study. A longitudinal study using the ADBB scale was conducted within the Eden Cohort in the year 2008. 1,586 infants were included in the study. Fourteen percent of the children who had an ADBB assessment had a score at 5 and over on the ADBB, a scale designed to assess social withdrawal behaviour at age 0-24 months. Social withdrawal at 12 months was associated with low birth weight, low gestational age and with intra uterine growth retardation. Social withdrawal was independently associated with several maternal and paternal risk factors. The level of social withdrawal behaviour increased with a score of maternal difficulties. This study on a large longitudinally followed volunteer sample demonstrate a clear association of social withdrawal behaviour at age one with low birth weight and preterm birth, possibly mediated by parental vulnerabilities. Social withdrawal behaviour seems to be an important alarm signal to detect early on particularly in premature and small for date babies. © Springer-Verlag 2012

  11. Withdrawal of food and fluid.

    Science.gov (United States)

    Daly, B J

    1990-05-01

    John S. is a 72-year-old patriarch of a large, extended family. He underwent a mitral and aortic valve replacement, followed by a complicated postoperative course. His recovery was complicated by hemodynamic instability, several cardiac arrests, acute renal failure, and sepsis. He has been in the ICU for 14 weeks and has been unable to wean from mechanical ventilation. After many conferences between the patient's family and the ICU staff, a decision was made to remove ventilator support. This was done 3 days ago. John's condition seems stable now, but it is clear that he will not regain his former state of health. He is very debilitated, may require chronic dialysis, and has suffered some anoxic brain damage during his arrests. The nursing and medical staff are now faced with the question of further withdrawal of treatment and are considering whether or not to discontinue his parenteral nutrition and all IV fluids.

  12. [An examination of the determinants of social withdrawal and affinity for social withdrawal].

    Science.gov (United States)

    Watanabe, Asami; Matsui, Yutaka; Takatsuka, Yusuke

    2010-12-01

    This study examined the determinants of social withdrawal using data from a survey by the Tokyo Metropolitan Government Office for Youth Affairs and Public Safety (2008). In addition, this study identified young people who showed an affinity for social withdrawal although they were not in a state of withdrawal, and examined the determinants of an affinity for social withdrawal. The results of stepwise discriminant analysis showed that factors such as social phobia, depression, violence, and emotional bonds with family differentiated between the general youth group and the social withdrawal group and the "affinity group". Social phobia, violence, and refusal to be interfered in self-decision making differentiated between the social withdrawal group and the "affinity group". This study shows that an "affinity group" should be cared as well as an actual withdrawal group.

  13. A Discovery of Strong Metal-Support Bonding in Nanoengineered Au-Fe3O4 Dumbbell-like Nanoparticles by in Situ Transmission Electron Microscopy.

    Science.gov (United States)

    Han, Chang Wan; Choksi, Tej; Milligan, Cory; Majumdar, Paulami; Manto, Michael; Cui, Yanran; Sang, Xiahan; Unocic, Raymond R; Zemlyanov, Dmitry; Wang, Chao; Ribeiro, Fabio H; Greeley, Jeffrey; Ortalan, Volkan

    2017-08-09

    The strength of metal-support bonding in heterogeneous catalysts determines their thermal stability, therefore, a tremendous amount of effort has been expended to understand metal-support interactions. Herein, we report the discovery of an anomalous "strong metal-support bonding" between gold nanoparticles and "nano-engineered" Fe 3 O 4 substrates by in situ microscopy. During in situ vacuum annealing of Au-Fe 3 O 4 dumbbell-like nanoparticles, synthesized by the epitaxial growth of nano-Fe 3 O 4 on Au nanoparticles, the gold nanoparticles transform into the gold thin films and wet the surface of nano-Fe 3 O 4 , as the surface reduction of nano-Fe 3 O 4 proceeds. This phenomenon results from a unique coupling of the size-and shape-dependent high surface reducibility of nano-Fe 3 O 4 and the extremely strong adhesion between Au and the reduced Fe 3 O 4 . This strong metal-support bonding reveals the significance of controlling the metal oxide support size and morphology for optimizing metal-support bonding and ultimately for the development of improved catalysts and functional nanostructures.

  14. The effect of threading dislocations on optical absorption and electron scattering in strongly mismatched heteroepitaxial III-V compound semiconductors on silicon

    CERN Document Server

    Peiner, E; Wehmann, H H

    2002-01-01

    The effect of threading dislocations on the optical and electrical properties of InP and GaAs heteroepitaxial layers on (001) silicon was investigated. Charged deep states act as scattering centres for electrons, thus affecting the electron mobility at low temperatures. The electric field arising from charged dislocations causes enhanced optical absorption at wavelengths near the fundamental absorption edge. The mean charge of the threading dislocations in GaAs/Si was found to be considerably higher than that for InP/Si. A model is described relating this effect to a regular arrangement of alpha-type 60 deg. dislocations at extended twin defects which were observed in InP/Si but were absent in GaAs/Si.

  15. Aspects of electron-phonon interactions with strong forward scattering in FeSe Thin Films on SrTiO3 substrates

    Science.gov (United States)

    Wang, Y.; Nakatsukasa, K.; Rademaker, L.; Berlijn, T.; Johnston, S.

    2016-05-01

    Mono- and multilayer FeSe thin films grown on SrTiO3 and BiTiO3 substrates exhibit a greatly enhanced superconductivity over that found in bulk FeSe. A number of proposals have been advanced for the mechanism of this enhancement. One possibility is the introduction of a cross-interface electron-phonon (e-ph) interaction between the FeSe electrons and oxygen phonons in the substrates that is peaked in the forward scattering (small {q}) direction due to the two-dimensional nature of the interface system. Motivated by this, we explore the consequences of such an interaction on the superconducting state and electronic structure of a two-dimensional system using Migdal-Eliashberg (ME) theory. This interaction produces not only deviations from the expectations of conventional phonon-mediated pairing but also replica structures in the spectral function and density of states, as probed by angle-resolved photoemission spectroscopy, scanning tunneling microscopy/spectroscopy, and quasiparticle interference imaging. We also discuss the applicability of ME theory for a situation where the e-ph interaction is peaked at small momentum transfer and in the FeSe/STO system.

  16. Investigations of the coherent hard photon yields from (50-300) GeV/c electrons/positrons in the strong crystalline fields of diamond, Si, and Ge crystals

    CERN Multimedia

    The aim of this experiment is to measure the influence of strong fields on QED-processes like: Emission of coherent radiation and pair-production when multi-hundred GeV electrons/positrons and photons penetrate single crystals near axial/planar directions. The targets will be diamond, Si, Ge and W crystals.\\\\\\\\ QED is a highly developed theory and has been investigated experimentally in great detail. In recent years it has become technically possible to investigate QED-processes in very strong electromagnetic fields around the characteristic strong field E$_{0}$ = m$^{2}$c$^{3}$/eh = 1.32.10$^{16}$ V/cm. The work of such a field over the Compton length equals the electron mass. The theoretical description of QED in such fields is beyond the framework of perturbation theory. Such fields are only obtained in laboratories for a) heavy ion collisions b) interactions of multi-GeV electrons with extremely intense laser fields and in oriented crystals. In fact it turns out that crystals are unique for this type of e...

  17. Pseudopheochromocytoma induced by anxiolytic withdrawal.

    Science.gov (United States)

    Páll, Alida; Becs, Gergely; Erdei, Annamária; Sira, Lívia; Czifra, Arpád; Barna, Sándor; Kovács, Péter; Páll, Dénes; Pfliegler, György; Paragh, György; Szabó, Zoltán

    2014-10-08

    Symptomatic paroxysmal hypertension without significantly elevated catecholamine concentrations and with no evidence of an underlying adrenal tumor is known as pseudopheochromocytoma. We describe the case of a female patient with paroxysmal hypertensive crises accompanied by headache, vertigo, tachycardia, nausea and altered mental status. Previously, she was treated for a longer period with alprazolam due to panic disorder. Causes of secondary hypertension were excluded. Neurological triggers (intracranial tumor, cerebral vascular lesions, hemorrhage, and epilepsy) could not be detected. Setting of the diagnosis of pseudopheochromocytoma treatment was initiated with alpha- and beta-blockers resulting in reduced frequency of symptoms. Alprazolam was restarted at a daily dose of 1 mg. The patient's clinical condition improved rapidly and the dosage of alpha- and beta-blockers could be decreased. We conclude that the withdrawal of an anxiolytic therapeutic regimen may generate sympathetic overdrive resulting in life-threatening paroxysmal malignant hypertension and secondary encephalopathy. We emphasize that pseudopheochromocytoma can be diagnosed only after exclusion of the secondary causes of hypertension. We highlight the importance of a psychopharmacological approach to this clinical entity.

  18. Phonon linewidth due to electron-phonon interactions with strong forward scattering in FeSe thin films on oxide substrates

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yan [Univ. of Tennessee, Knoxville, TN (United States); Rademaker, Louk [Univ. of California, Santa Barbara, CA (United States); Dagotto, Elbio R. [Univ. of Tennessee, Knoxville, TN (United States); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Johnston, Steven [Univ. of Tennessee, Knoxville, TN (United States)

    2017-08-18

    Here, the discovery of an enhanced superconducting transition temperature Tc in monolayers of FeSe grown on several oxide substrates has opened a new route to high-Tc superconductivity through interface engineering. One proposal for the origin of the observed enhancement is an electronphonon (e-ph) interaction across the interface that peaked at small momentum transfers. In this paper, we examine the implications of such a coupling on the phononic properties of the system. We show that a strong forward scattering leads to a sizable broadening of phonon lineshape, which may result in charge instabilities at long-wavelengths. However, we further find that the inclusion of Coulombic screening significantly reduces the phonon broadening. Our results show that one might not expect anomalously broad phonon linewidths in the FeSe interface systems, despite the fact that the e-ph interaction has a strong peak in the forward scattering (small \\bfq ) direction.

  19. Electron–Cyclotron Laser Using Free-Electron Two-Quantum Stark Radiation in a Strong Uniform Axial Magnetic Field and an Alternating Axial Electric Field in a Voltage-Supplied Pill-Box Cavity

    International Nuclear Information System (INIS)

    Kim, S. H.

    2016-01-01

    We consider the radiation from the beam electrons traveling in a strong uniform axial magnetic field and an axial alternating electric field of wavelength λ_w generated by a voltage-supplied pill-box cavity. The beam electrons emit genuine laser radiation that propagates only in the axial direction through free-electron two-quantum Stark radiation. We find that laser radiation takes place only at the expense of the axial kinetic energy when λ_w ≪ c/(ω_c/γ), where ω_c/γ is the relativistic electron–cyclotron frequency. We formulate the laser power based on quantum-wiggler electrodynamics, and envision a laser of length 10 m with estimated power 0.1 GW/(kA) in the 10"−"4 cm wavelength range. (paper)

  20. 21 CFR 314.530 - Withdrawal procedures.

    Science.gov (United States)

    2010-04-01

    ... Serious or Life-Threatening Illnesses § 314.530 Withdrawal procedures. (a) For new drugs approved under... benefit; (2) The applicant fails to perform the required postmarketing study with due diligence; (3) Use...

  1. MITS Feed and Withdrawal Subsystem: operating procedures

    International Nuclear Information System (INIS)

    Brown, W.S.

    1980-01-01

    This procedure details the steps required to provide continuous feed flow and withdrawal of process product and waste flows in support of thruput operation in the cascade or its elements. It particularly requires operator attention to safety considerations

  2. Two-photon excited fluorescence from higher electronic states of chlorophylls in photosynthetic antenna complexes a new approach to detect strong excitonic chlorophyll a/b coupling

    CERN Document Server

    Leupold, D; Ehlert, J; Irrgang, K D; Renger, G; Lokstein, H

    2002-01-01

    Stepwise two-photon excitation of chlorophyll a and b in the higher plant main light-harvesting complex (LHC II) and the minor complex CP29 (as well as in organic solution) with 100-fs pulses in the Q/sub y/ region results in a weak blue fluorescence. The dependence of the spectral shape of the blue fluorescence on excitation wavelength offers a new approach to elucidate the long-standing problem of the origin of spectral "chlorophyll forms" in pigment-protein complexes, in particular the characterization of chlorophyll a/b-heterodimers. As a first result we present evidence for the existence of strong chlorophyll a/b-interactions (excitonically coupled transitions at 650 and 680 nm) in LHC II at ambient temperature. In comparison with LHC II, the experiments with CP29 provide further evidence that the lowest energy chlorophyll a transition (at ~680 nm) is not excitonically coupled to chlorophyll b. (22 refs).

  3. Inhomogeneous spectral moment sum rules for the retarded Green function and self-energy of strongly correlated electrons or ultracold fermionic atoms in optical lattices

    International Nuclear Information System (INIS)

    Freericks, J. K.; Turkowski, V.

    2009-01-01

    Spectral moment sum rules are presented for the inhomogeneous many-body problem described by the fermionic Falicov-Kimball or Hubbard models. These local sum rules allow for arbitrary hoppings, site energies, and interactions. They can be employed to quantify the accuracy of numerical solutions to the inhomogeneous many-body problem such as strongly correlated multilayered devices, ultracold atoms in an optical lattice with a trap potential, strongly correlated systems that are disordered, or systems with nontrivial spatial ordering such as a charge-density wave or a spin-density wave. We also show how the spectral moment sum rules determine the asymptotic behavior of the Green function, self-energy, and dynamical mean field when applied to the dynamical mean-field theory solution of the many-body problem. In particular, we illustrate in detail how one can dramatically reduce the number of Matsubara frequencies needed to solve the Falicov-Kimball model while still retaining high precision, and we sketch how one can incorporate these results into Hirsch-Fye quantum Monte Carlo solvers for the Hubbard (or more complicated) models. Since the solution of inhomogeneous problems is significantly more time consuming than periodic systems, efficient use of these sum rules can provide a dramatic speed up in the computational time required to solve the many-body problem. We also discuss how these sum rules behave in nonequilibrium situations as well, where the Hamiltonian has explicit time dependence due to a driving field or due to the time-dependent change in a parameter such as the interaction strength or the origin of the trap potential.

  4. Tobacco withdrawal among opioid-dependent smokers.

    Science.gov (United States)

    Streck, Joanna M; Heil, Sarah H; Higgins, Stephen T; Bunn, Janice Y; Sigmon, Stacey C

    2018-04-01

    Prevalence of cigarette smoking among opioid-dependent individuals is 6-fold that of the general U.S. adult population and their quit rates are notoriously poor. One possible reason for the modest cessation outcomes in opioid-dependent smokers may be that they experience more severe tobacco withdrawal upon quitting. In this secondary analysis, we evaluated tobacco withdrawal in opioid-dependent (OD) smokers versus smokers without co-occurring substance use disorders (SUDs). Participants were 47 methadone- or buprenorphine-maintained smokers and 25 non-SUD smokers who completed 1 of several 2-week studies involving daily visits for biochemical monitoring, delivery of financial incentives contingent on smoking abstinence, and assessment of withdrawal via the Minnesota Nicotine Withdrawal Scale (MNWS). Prior to quitting smoking, OD smokers presented with higher baseline withdrawal scores than non-SUD smokers (1.7 ± 0.2 vs. 0.7 ± 0.2, respectively; F [1, 63] = 7.31, p non-SUD smokers, suggesting that elevated withdrawal severity following quitting may not be a major factor contributing to the poor cessation outcomes consistently observed among OD smokers. Further scientific efforts are needed to improve our understanding of the high smoking rates and modest cessation outcomes in this challenging population. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

  5. 20 CFR 408.355 - Can you withdraw your application?

    Science.gov (United States)

    2010-04-01

    ... Section 408.355 Employees' Benefits SOCIAL SECURITY ADMINISTRATION SPECIAL BENEFITS FOR CERTAIN WORLD WAR II VETERANS Filing Applications Withdrawal of Application § 408.355 Can you withdraw your application? (a) Request for withdrawal filed before a determination is made. You may withdraw your application...

  6. 19 CFR 144.38 - Withdrawal for consumption.

    Science.gov (United States)

    2010-04-01

    ... 19 Customs Duties 2 2010-04-01 2010-04-01 false Withdrawal for consumption. 144.38 Section 144.38... Withdrawal for consumption. (a) Form. Withdrawals for consumption of merchandise in bonded warehouses shall... considered a withdrawal for consumption pursuant to § 181.53 of this chapter. (c) Information to be shown on...

  7. 21 CFR 514.7 - Withdrawal of applications without prejudice.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Withdrawal of applications without prejudice. 514... Withdrawal of applications without prejudice. The sponsor may withdraw his pending application from.... Such withdrawal may be made without prejudice to a future filing. Upon resubmission, the time...

  8. A calorimetric measurement of the strong coupling constant in electron-positron annihilation at a center-of-mass energy of 91.6 GeV

    International Nuclear Information System (INIS)

    Martirena, S.G.

    1994-04-01

    In this work, a measurement of the strong coupling constant α s in e + e - annihilation at a center-of-mass energy of 91.6 GeV is presented. The measurement was performed with the SLD at the Stanford Linear Collider facility located at the Stanford Linear Accelerator Center in California. The procedure used consisted of measuring the rate of hard gluon radiation from the primary quarks in a sample of 9,878 hadronic events. After defining the asymptotic manifestation of partons as 'jets', various phenomenological models were used to correct for the hadronization process. A value for the QCD scale parameter Λ bar MS , defined in the bar MS renormalization convention with 5 active quark flavors, was then obtained by a direct fit to O(α s 2 ) calculations. The value of α s obtained was α s (M z0 ) = 0.122 ± 0.004 -0.007 +0.008 where the uncertainties are experimental (combined statistical and systematic) and theoretical (systematic) respectively. Equivalently, Λ bar MS = 0.28 -0.10 +0.16 GeV where the experimental and theoretical uncertainties have been combined

  9. Electronics

    Science.gov (United States)

    2001-01-01

    International Acer Incorporated, Hsin Chu, Taiwan Aerospace Industrial Development Corporation, Taichung, Taiwan American Institute of Taiwan, Taipei, Taiwan...Singapore and Malaysia .5 - 4 - The largest market for semiconductor products is the high technology consumer electronics industry that consumes up...Singapore, and Malaysia . A new semiconductor facility costs around $3 billion to build and takes about two years to become operational

  10. Effect of Electronic Reminders, Financial Incentives, and Social Support on Outcomes After Myocardial Infarction: The HeartStrong Randomized Clinical Trial.

    Science.gov (United States)

    Volpp, Kevin G; Troxel, Andrea B; Mehta, Shivan J; Norton, Laurie; Zhu, Jingsan; Lim, Raymond; Wang, Wenli; Marcus, Noora; Terwiesch, Christian; Caldarella, Kristen; Levin, Tova; Relish, Mike; Negin, Nathan; Smith-McLallen, Aaron; Snyder, Richard; Spettell, Claire M; Drachman, Brian; Kolansky, Daniel; Asch, David A

    2017-08-01

    Adherence to medications prescribed after acute myocardial infarction (AMI) is low. Wireless technology and behavioral economic approaches have shown promise in improving health behaviors. To determine whether a system of medication reminders using financial incentives and social support delays subsequent vascular events in patients following AMI compared with usual care. Two-arm, randomized clinical trial with a 12-month intervention conducted from 2013 through 2016. Investigators were blinded to study group, but participants were not. Design was a health plan-intermediated intervention for members of several health plans. We recruited 1509 participants from 7179 contacted AMI survivors (insured with 5 large US insurers nationally or with Medicare fee-for-service at the University of Pennsylvania Health System). Patients aged 18 to 80 years were eligible if currently prescribed at least 2 of 4 study medications (statin, aspirin, β-blocker, antiplatelet agent), and were hospital inpatients for 1 to 180 days and discharged home with a principal diagnosis of AMI. Patients were randomized 2:1 to an intervention using electronic pill bottles combined with lottery incentives and social support for medication adherence (1003 patients), or to usual care (506 patients). Primary outcome was time to first vascular rehospitalization or death. Secondary outcomes were time to first all-cause rehospitalization, total number of repeated hospitalizations, medication adherence, and total medical costs. A total of 35.5% of participants were female (n = 536); mean (SD) age was 61.0 (10.3) years. There were no statistically significant differences between study arms in time to first rehospitalization for a vascular event or death (hazard ratio, 1.04; 95% CI, 0.71 to 1.52; P = .84), time to first all-cause rehospitalization (hazard ratio, 0.89; 95% CI, 0.73 to 1.09; P = .27), or total number of repeated hospitalizations (hazard ratio, 0.94; 95% CI, 0.60 to 1.48; P

  11. Control rod excess withdrawal prevention device

    International Nuclear Information System (INIS)

    Takayama, Yoshihito.

    1992-01-01

    Excess withdrawal of a control rod of a BWR type reactor is prevented. That is, the device comprises (1) a speed detector for detecting the driving speed of a control rod, (2) a judging circuit for outputting an abnormal signal if the driving speed is greater than a predetermined level and (3) a direction control valve compulsory closing circuit for controlling the driving direction of inserting and withdrawing a control rod based on an abnormal signal. With such a constitution, when the with drawing speed of a control rod is greater than a predetermined level, it is detected by the speed detector and the judging circuit. Then, all of the direction control valve are closed by way of the direction control valve compulsory closing circuit. As a result, the operation of the control rod is stopped compulsorily and the withdrawing speed of the control rod can be lowered to a speed corresponding to that upon gravitational withdrawal. Accordingly, excess withdrawal can be prevented. (I.S)

  12. Withdrawal-oriented therapy for smokers.

    Science.gov (United States)

    Hajek, P

    1989-06-01

    The treatment approach of the Maudsley Hospital Smokers Clinic is described. It stems from the notion that smokers seeking help are dependent on nicotine, and that withdrawal discomfort is a major block to their success in quitting. Accordingly, therapy focuses on helping clients overcome nicotine deprivation. It uses nicotine replacement and a special format of group treatment. Details are given of preparation of clients, use of nicotine chewing gum, use of group-oriented groupwork, use of information about withdrawal, and training in withdrawal-oriented therapy. Data are presented concerning characteristics of the clientele, treatment adherence, and treatment results. A number of controversial issues are addressed, such as the optimal duration of treatment, timing of the quit date, the value of educational input, and the value of individualization of treatment goals.

  13. [Treatment of gamma-hydroxybutyrate withdrawal].

    Science.gov (United States)

    Strand, Niels August Willer; Petersen, Tonny Studsgaard; Nielsen, Lars Martin; Boegevig, Soren

    2017-12-11

    Gamma-hydroxybutyrate (GHB) is a drug of abuse, for which physical addiction develops quickly. GHB withdrawal can develop into a life-threatening condition and has previously been treated mainly with benzodiazepines. These have not always proven effective, leading to long hospitalizations in intensive care units. Based on successful Dutch treatment results for using GHB to treat GHB withdrawal symptoms, we propose to implement a similar method in Denmark. The method requires an interdisciplinary effort for which The Danish Poison Information Centre should be consulted for expertise.

  14. Children's judgements of social withdrawal behaviours.

    Science.gov (United States)

    Watling, Dawn

    2015-06-01

    Ding et al. (Brit. J. Dev. Psychol., 2015; 33, 159-173) demonstrated that Chinese children discriminate between the three subtypes of social withdrawal: Shyness, unsociability, and social avoidance. This commentary on the Ding et al.'s paper highlights the need to further explore the following: (1) children's understanding of the implications of being shy, unsociable, or socially avoidant, including assessing these which we know are associated with outcomes for socially withdrawn children; (2) what additional subtypes might exist naturally within the Chinese culture; and (3) consider the implications of social withdrawal on children's developing social skills. © 2015 The British Psychological Society.

  15. Sleep-disordered breathing decreases after opioid withdrawal: results of a prospective controlled trial.

    Science.gov (United States)

    Schwarzer, Andreas; Aichinger-Hinterhofer, Marie; Maier, Christoph; Vollert, Jan; Walther, Jörg Werner

    2015-11-01

    An increased cardiovascular event rate in elderly patients under opioid medications was recently reported. One reason for this increase could be the occurrence of nocturnal apnea and hypoxia, as a consequence of sleep-disordered breathing (SDB). Using a controlled study, we prospectively analyzed SDB using polysomnography in a total of 18 patients before and after opioid withdrawal (opioid withdrawal group [OG]) and 14 patients before and after comprehensive pain management (without any strong-acting opioids) who served as the control group (CG). To analyze the differences, unpaired/paired t tests and Mann-Whitney U tests/Wilcoxon rank tests were used. At baseline, the OG presented more nocturnal apneas/hypopneas than the CG with an apnea-hypopnea index (AHI) of 41.4 ± 27.8 vs 21.8 ± 15.9 (P = 0.018). After treatment, the AHI decreased significantly only in the withdrawal group (OG: 16.7 ± 8.9; CG: 20.1 ± 12.9) (P opioid withdrawal and in none of the patients after withdrawal (P opioid intake; these findings may explain the opioid-associated cardiovascular morbidity. Thus, SDB may be a risk at lower opioid doses than hitherto described, and particular caution should be exercised in patients with comorbidities that might make them vulnerable to the consequences of SDB.

  16. INVERSE ELECTRON TRANSFER IN PEROXYOXALATE CHEMIEXCITATION USING EASILY REDUCIBLE ACTIVATORS

    NARCIS (Netherlands)

    Bartoloni, Fernando Heering; Monteiro Leite Ciscato, Luiz Francisco; Augusto, Felipe Alberto; Baader, Wilhelm Josef

    2010-01-01

    INVERSE ELECTRON TRANSFER IN PEROXYOXALATE CHEMIEXCITATION USING EASILY REDUCIBLE ACTIVATORS. Chemiluminescence properties of the peroxyoxalate reaction in the presence of activators bearing electron withdrawing substituents were studied, to evaluate the possible occurrence of an inverse electron

  17. Teachers' Withdrawal Behaviors: Integrating Theory and Findings

    Science.gov (United States)

    Shapira-Lishchinsky, Orly

    2012-01-01

    Purpose: The article aims to investigate the relationships between different dimensions of organizational ethics and different withdrawal symptoms--lateness, absence, and intent to leave work. Design/methodology/approach: Participants were 1,016 school teachers from 35 high schools in Israel. A joint model of Glimmix procedure of SAS was used for…

  18. Withholding and withdrawing treatment: practical applications of ...

    African Journals Online (AJOL)

    Withholding and withdrawing treatment: practical applications of ethical principles in end-of-life care. L Gwyther. Abstract. No Abstract South African Journal of Bioethics and Law Vol. 1 (1) 2008: pp. 24-26. Full Text: EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT.

  19. Recent advances in alcohol withdrawal states.

    Science.gov (United States)

    Fialkov, M J

    1977-11-26

    Recent advances in alcohol withdrawal states are described. New concepts of classification, the development of the syndrome and its management are outlined. In the light of recent research, more optimistic results for this much maligned but common condition may be achieved.

  20. MITS Feed and Withdrawal Subsystem: operating procedures

    International Nuclear Information System (INIS)

    Brown, W.S.

    1980-01-01

    This document details procedures for the operation of the MITS (Machine Interface Test System) Feed and Withdrawal Subsystem (F and W). Included are fill with UF 6 , establishment of recycle and thruput flows, shutdown, UF 6 makeup, dump to supply container, Cascade dump to F and W, and lights cold trap dump, all normal procedures, plus an alternate procedure for trapping light gases

  1. MITS Feed and Withdrawal Subsystem: operating procedures

    International Nuclear Information System (INIS)

    Brown, W.S.

    1980-01-01

    This procedure details the steps involved in filling two of the four MITS (Machine Interface Test System) Feed and Withdrawal subsystem main traps and the Sample/Inventory Make-up Pipette with uranium hexafluoride from the ''AS RECEIVED'' UF 6 supply

  2. Evaluation of Ashwagandha in alcohol withdrawal syndrome

    Directory of Open Access Journals (Sweden)

    Ruby B

    2012-10-01

    Full Text Available Objective: To evaluate the effect of Ashwagandha (ASW in attenuation of alcohol withdrawal in ethanol withdrawal mice model. Methods: Alcohol dependence was induced in mice by the oral, once-daily administration of 10% v/v ethanol (2 g/kg for one week. Once the animals were withdrawn from alcohol, the efficacy of ASW (200mg/kg and 500mg/kg in comparison with diazepam (1 mg/kg in the attenuation of withdrawal was studied using, pentylenetetrazole (PTZ kindling test for seizure threshold, forced swim test (FST for depression and locomotor activity (LCA in open field test (OFT. 6 hours after the last ethanol administration, seizure threshold was measured in all the groups by administering the convulsant drug, PTZ with a subconvulsive dose of 30 mg/kg i.p. In FST, mice were forced to swim and the total duration of immobility (seconds was measured during the last 4 min of a single 6-min test session. In OFT, number of crossings of the lines marked on the floor was recorded for a period of 5 min. Results: Compared to ethanol group, ASW (500 mg/Kg has suppressed the PTZ kindling seizures in ethanol withdrawal animals [0% convulsion], FST has shown decreased immobility time and OFT has exhibited increase in the number of line crossing activity by mice which may be the consequence of anxiolytic activity of ASW similar to that of diazepam. Conclusions: The present study provides satisfactory evidence to use ASW as a safe and reliable alternative to diazepam in alcohol withdrawal conditions.

  3. The colours of strong interaction

    International Nuclear Information System (INIS)

    1995-01-01

    The aim of this session is to draw a consistent framework about the different ways to consider strong interaction. A large part is dedicated to theoretical work and the latest experimental results obtained at the first electron collider HERA are discussed. (A.C.)

  4. The unusually strong hydrogen bond between the carbonyl of Q(A) and His M219 in the Rhodobacter sphaeroides reaction center is not essential for efficient electron transfer from Q(A)(-) to Q(B).

    Science.gov (United States)

    Breton, Jacques; Lavergne, Jérôme; Wakeham, Marion C; Nabedryk, Eliane; Jones, Michael R

    2007-06-05

    In native reaction centers (RCs) from photosynthetic purple bacteria the primary quinone (QA) and the secondary quinone (QB) are interconnected via a specific His-Fe-His bridge. In Rhodobacter sphaeroides RCs the C4=O carbonyl of QA forms a very strong hydrogen bond with the protonated Npi of His M219, and the Ntau of this residue is in turn coordinated to the non-heme iron atom. The second carbonyl of QA is engaged in a much weaker hydrogen bond with the backbone N-H of Ala M260. In previous work, a Trp side chain was introduced by site-directed mutagenesis at the M260 position in the RC of Rb. sphaeroides, resulting in a complex that is completely devoid of QA and therefore nonfunctional. A photochemically competent derivative of the AM260W mutant was isolated that contains a Cys side chain at the M260 position (denoted AM260(W-->C)). In the present work, the interactions between the carbonyl groups of QA and the protein in the AM260(W-->C) suppressor mutant have been characterized by light-induced FTIR difference spectroscopy of the photoreduction of QA. The QA-/QA difference spectrum demonstrates that the strong interaction between the C4=O carbonyl of QA and His M219 is lost in the mutant, and the coupled CO and CC modes of the QA- semiquinone are also strongly perturbed. In parallel, a band assigned to the perturbation of the C5-Ntau mode of His M219 upon QA- formation in the native RC is lacking in the spectrum of the mutant. Furthermore, a positive band between 2900 and 2400 cm-1 that is related to protons fluctuating within a network of highly polarizable hydrogen bonds in the native RC is reduced in amplitude in the mutant. On the other hand, the QB-/QB FTIR difference spectrum is essentially the same as for the native RC. The kinetics of electron transfer from QA- to QB were measured by the flash-induced absorption changes at 780 nm. Compared to native RCs the absorption transients are slowed by a factor of about 2 for both the slow phase (in the

  5. A psychometric validation of the Short Alcohol Withdrawal Scale (SAWS)

    DEFF Research Database (Denmark)

    Elholm, Bjarne; Larsen, Klaus; Hornnes, Nete

    2010-01-01

    The study aimed to evaluate psychometrically a Danish translation of the Short Alcohol Withdrawal Scale (SAWS) in an outpatient setting in patients with Alcohol Dependence (AD) and Alcohol Withdrawal Symptoms/Syndrome (AWS).......The study aimed to evaluate psychometrically a Danish translation of the Short Alcohol Withdrawal Scale (SAWS) in an outpatient setting in patients with Alcohol Dependence (AD) and Alcohol Withdrawal Symptoms/Syndrome (AWS)....

  6. An overview of research on social withdrawal in childhood

    OpenAIRE

    野村, あすか; NOMURA, Asuka

    2013-01-01

    In recent years, “HIKIKOMORI” in adolescence or adulthood has grown into a serious problem in Japan and the need for early intervention and support has been emphasized. Among the risk factors of “HIKIKOMORI” is social withdrawal in childhood. With this in mind, I reviewed previous studies on the social withdrawal in children living abroad. The review commences with an examination of definitions of social withdrawal, which showed that in some foreign countries, social withdrawal refers to the ...

  7. 19 CFR 144.36 - Withdrawal for transportation.

    Science.gov (United States)

    2010-04-01

    ... 19 Customs Duties 2 2010-04-01 2010-04-01 false Withdrawal for transportation. 144.36 Section 144... § 144.36 Withdrawal for transportation. (a) Time limit. Merchandise may be withdrawn from warehouse for transportation to another port of entry if withdrawal for consumption or exportation can be accomplished at the...

  8. 19 CFR 144.37 - Withdrawal for exportation.

    Science.gov (United States)

    2010-04-01

    ...) Class 9 warehouse withdrawals for exportation—(1) Applicability of sales ticket procedure. Merchandise... be eligible for withdrawal under the sales ticket procedure specified in this paragraph. (2) Sales ticket content and handling. Sales ticket withdrawals must be made only under a blanket permit to...

  9. 47 CFR 1.8 - Withdrawal of papers.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 1 2010-10-01 2010-10-01 false Withdrawal of papers. 1.8 Section 1.8 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL PRACTICE AND PROCEDURE General Rules of Practice and Procedure General § 1.8 Withdrawal of papers. The granting of a request to dismiss or withdraw an...

  10. 5 CFR 362.207 - Withdrawal and readmission.

    Science.gov (United States)

    2010-01-01

    ... 5 Administrative Personnel 1 2010-01-01 2010-01-01 false Withdrawal and readmission. 362.207... PRESIDENTIAL MANAGEMENT FELLOWS PROGRAM Program Administration § 362.207 Withdrawal and readmission. (a...) An agency must notify OPM when a Fellow or Senior Fellow withdraws from the Program. (b) Readmission...

  11. 45 CFR 400.301 - Withdrawal from the refugee program.

    Science.gov (United States)

    2010-10-01

    ... 45 Public Welfare 2 2010-10-01 2010-10-01 false Withdrawal from the refugee program. 400.301... Waivers and Withdrawals § 400.301 Withdrawal from the refugee program. (a) In the event that a State... assistance, social services, preventive health, and an unaccompanied minors program if appropriate. A State...

  12. 20 CFR 404.640 - Withdrawal of an application.

    Science.gov (United States)

    2010-04-01

    ... 20 Employees' Benefits 2 2010-04-01 2010-04-01 false Withdrawal of an application. 404.640 Section 404.640 Employees' Benefits SOCIAL SECURITY ADMINISTRATION FEDERAL OLD-AGE, SURVIVORS AND DISABILITY INSURANCE (1950- ) Filing of Applications and Other Forms Withdrawal of Application § 404.640 Withdrawal of...

  13. 20 CFR 416.355 - Withdrawal of an application.

    Science.gov (United States)

    2010-04-01

    ... 20 Employees' Benefits 2 2010-04-01 2010-04-01 false Withdrawal of an application. 416.355 Section 416.355 Employees' Benefits SOCIAL SECURITY ADMINISTRATION SUPPLEMENTAL SECURITY INCOME FOR THE AGED, BLIND, AND DISABLED Filing of Applications Withdrawal of Application § 416.355 Withdrawal of an...

  14. 29 CFR 102.104 - Withdrawal of petition.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 2 2010-07-01 2010-07-01 false Withdrawal of petition. 102.104 Section 102.104 Labor... Orders and Advisory Opinions Regarding Board Jurisdiction § 102.104 Withdrawal of petition. The petitioner may withdraw his petition at any time prior to issuance of the Board's advisory opinion. ...

  15. 15 CFR 10.13 - Withdrawal of a published standard.

    Science.gov (United States)

    2010-01-01

    ...) Before withdrawing a standard published under these procedures, the Director will review the relative... 15 Commerce and Foreign Trade 1 2010-01-01 2010-01-01 false Withdrawal of a published standard. 10... DEVELOPMENT OF VOLUNTARY PRODUCT STANDARDS § 10.13 Withdrawal of a published standard. (a) Standards published...

  16. 21 CFR 171.7 - Withdrawal of petition without prejudice.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Withdrawal of petition without prejudice. 171.7... Withdrawal of petition without prejudice. (a) In some cases the Commissioner will notify the petitioner that... clarification or the obtaining of additional data. This withdrawal will be without prejudice to a future filing...

  17. 21 CFR 571.7 - Withdrawal of petition without prejudice.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Withdrawal of petition without prejudice. 571.7... Withdrawal of petition without prejudice. (a) In some cases the Commissioner will notify the petitioner that... clarification or the obtaining of additional data. This withdrawal will be without prejudice to a future filing...

  18. Radionuclide withdrawal from animal and human body

    International Nuclear Information System (INIS)

    Arkhipov, A.S.; Sidorova, T.F.

    1995-01-01

    The authors review the history of the problem of radionuclide withdrawal from animal and human body and discuss methodological approaches to it. Results of studies of radionuclide elimination by means of chemical and bioactive substances are analyzed. Special attention is paid to decorporation of radioactive elements which are the most hazardous as regards intoxication in connection with the Chernobyl accident: 131 I, 89 St and 90 Sr, 137 Cs, 238 Pu, and 241 Am. The authors analyze the results of studies of radionuclide withdrawal based on the dissolution effect, ionic antagonism, and by means of complexons, carried out in humans and animals. Efficacies of alimentary fibers and other adsorbents, foodstuffs and drinks are demonstrated. 48 refs

  19. John Strong (1941 - 2006)

    CERN Multimedia

    Wickens, F

    Our friend and colleague John Strong was cruelly taken from us by a brain tumour on Monday 31st July, a few days before his 65th birthday John started his career working with a group from Westfield College, under the leadership of Ted Bellamy. He obtained his PhD and spent the early part of his career on experiments at Rutherford Appleton Laboratory (RAL), but after the early 1970s his research was focussed on experiments in CERN. Over the years he made a number of notable contributions to experiments in CERN: The Omega spectrometer adopted a system John had originally developed for experiments at RAL using vidicon cameras to record the sparks in the spark chambers; He contributed to the success of NA1 and NA7, where he became heavily involved in the electronic trigger systems; He was responsible for the second level trigger system for the ALEPH detector and spent five years leading a team that designed and built the system, which ran for twelve years with only minor interventions. Following ALEPH he tur...

  20. SSRI and SNRI withdrawal symptoms reported on an internet forum.

    Science.gov (United States)

    Stockmann, Tom; Odegbaro, Dolapo; Timimi, Sami; Moncrieff, Joanna

    2018-05-09

    Antidepressant withdrawal symptoms are well-recognised, but their potential duration remains uncertain. We aimed to describe the characteristics of withdrawal associated with two popular classes of antidepressants, including duration. We analysed the content of a sample of posts on an antidepressant withdrawal website. We compared the characteristics of withdrawal associated with SSRIs and SNRIs, including time of onset, duration and nature of symptoms. 110 posts about SSRI withdrawal, and 63 concerning SNRI withdrawal, were analysed. The mean duration of withdrawal symptoms was significantly longer with SSRIs than SNRIs: 90.5 weeks (standard deviation, SD, 150.0) and 50.8 weeks (SD 76.0) respectively; p = 0.043). Neurological symptoms, such as 'brain zaps,' were more common among SNRI users (p = 0.023). Psychosexual/genitourinary symptoms may be more common among SSRI users (p = 0.054). The website aims to help people with antidepressant withdrawal, and is therefore likely to attract people who have difficulties. Length of prior use of antidepressants was long, with a mean of 252.2 weeks (SD 250.8). People accessing antidepressant withdrawal websites report experiencing protracted withdrawal symptoms. There are some differences in the characteristics of withdrawal associated with different classes of antidepressants.

  1. Moves to withdraw nuclear weapons from NATO?

    International Nuclear Information System (INIS)

    Dumoulin, A.

    2008-01-01

    The American nuclear landscape in Europe could change in the coming months. The signs are already there, and a new strategic posture will have major implications for the Europeans as well as for the visibility of France deterrent force. Nonetheless, the Georgian crisis, tensions with Iran, Russian muscle flexing and NATO's line cast doubt on the idea that a partial or even complete withdrawal of American B-61 bombs could be on the agenda at the Alliance's 60. anniversary in April 2009. (author)

  2. Vagal withdrawal during endoscopic retrograde cholangiopancreatography

    DEFF Research Database (Denmark)

    Christensen, M; Rasmussen, Verner; Schulze, S

    2000-01-01

    BACKGROUND: Patients undergoing endoscopic retrograde cholangiopancreatography (ERCP) are at risk of developing cardiorespiratory complications, but the mechanism is still unknown. Treatment with metoprolol 2 h before the endoscopy has been shown to decrease the incidence of myocardial ischaemia......: The existence of a defence-like reaction ('vagal withdrawal') during ERCP has been shown. Metoprolol given 2 h before the procedure did not affect the occurrence of this phenomenon. The interaction of other periendoscopic factors is still unclear and should be studied further....

  3. Atoms in strong laser fields

    International Nuclear Information System (INIS)

    L'Huillier, A.

    2002-01-01

    When a high-power laser focuses into a gas of atoms, the electromagnetic field becomes of the same magnitude as the Coulomb field which binds a 1s electron in a hydrogen atom. 3 highly non-linear phenomena can happen: 1) ATI (above threshold ionization): electrons initially in the ground state absorb a large number of photons, many more than the minimum number required for ionization; 2) multiple ionization: many electrons can be emitted one at a time, in a sequential process, or simultaneously in a mechanism called direct or non-sequential; and 3) high order harmonic generation (HHG): efficient photon emission in the extreme ultraviolet range, in the form of high-order harmonics of the fundamental laser field can occur. The theoretical problem consists in solving the time dependent Schroedinger equation (TDSE) that describes the interaction of a many-electron atom with a laser field. A number of methods have been proposed to solve this problem in the case of a hydrogen atom or a single-active electron atom in a strong laser field. A large effort is presently being devoted to go beyond the single-active approximation. The understanding of the physics of the interaction between atoms and strong laser fields has been provided by a very simple model called ''simple man's theory''. A unified view of HHG, ATI, and non-sequential ionization, originating from the simple man's model and the strong field approximation, expressed in terms of electrons trajectories or quantum paths is slowly emerging. (A.C.)

  4. Strong-field dissociation dynamics

    International Nuclear Information System (INIS)

    DiMauro, L.F.; Yang, Baorui.

    1993-01-01

    The strong-field dissociation behavior of diatomic molecules is examined under two distinctive physical scenarios. In the first scenario, the dissociation of the isolated hydrogen and deuterium molecular ions is discussed. The dynamics of above-threshold dissociation (ATD) are investigated over a wide range of green and infrared intensities and compared to a dressed-state model. The second situation arises when strong-field neutral dissociation is followed by ionization of the atomic fragments. The study results in a direct measure of the atomic fragment's ac-Stark shift by observing the intensity-dependent shifts in the electron or nuclear fragment kinetic energy. 8 figs., 14 refs

  5. Sedatives for opiate withdrawal in newborn infants.

    Science.gov (United States)

    Osborn, David A; Jeffery, Heather E; Cole, Michael J

    2010-10-06

    Neonatal abstinence syndrome (NAS) due to opiate withdrawal may result in disruption of the mother-infant relationship, sleep-wake abnormalities, feeding difficulties, weight loss and seizures. Treatments used to ameliorate symptoms and reduce morbidity include opiates, sedatives and non-pharmacological treatments. To assess the effectiveness and safety of using a sedative compared to a non-opiate control for NAS due to withdrawal from opiates, and to determine which type of sedative is most effective and safe. This update included searches of the Cochrane Central Register of Controlled Trials (Issue 1, 2010), MEDLINE 1966 to April 2010 and abstracts of conference proceedings. Trials enrolling infants with NAS born to mothers with an opiate dependence with > 80% follow-up and using random or quasi-random allocation to sedative or control. Control could include another sedative or non-pharmacological treatment. Each author assessed study quality and extracted data independently. Seven studies enrolling 385 patients were included. There were substantial methodological concerns for most studies including the use of quasi-random allocation methods and sizeable, largely unexplained differences in reported numbers allocated to each group.One study reported phenobarbitone compared to supportive care alone did not reduce treatment failure or time to regain birthweight, but resulted in a significant reduction in duration of supportive care (MD -162.1 min/day, 95% CI -249.2, -75.1). Comparing phenobarbitone to diazepam, meta-analysis of two studies found phenobarbitone resulted in a significant reduction in treatment failure (typical RR 0.39, 95% CI 0.24, 0.62). Comparing phenobarbitone with chlorpromazine, one study reported no significant difference in treatment failure.In infants treated with an opiate, one study reported addition of clonidine resulted in no significant difference in treatment failure, seizures or mortality. In infants treated with an opiate, one study

  6. Rydberg atoms in strong fields

    International Nuclear Information System (INIS)

    Kleppner, D.; Tsimmerman, M.

    1985-01-01

    Experimental and theoretical achievements in studying Rydberg atoms in external fields are considered. Only static (or quasistatic) fields and ''one-electron'' atoms, i.e. atoms that are well described by one-electron states, are discussed. Mainly behaviour of alkali metal atoms in electric field is considered. The state of theoretical investigations for hydrogen atom in magnetic field is described, but experimental data for atoms of alkali metals are presented as an illustration. Results of the latest experimental and theoretical investigations into the structure of Rydberg atoms in strong fields are presented

  7. Testing strong interaction theories

    International Nuclear Information System (INIS)

    Ellis, J.

    1979-01-01

    The author discusses possible tests of the current theories of the strong interaction, in particular, quantum chromodynamics. High energy e + e - interactions should provide an excellent means of studying the strong force. (W.D.L.)

  8. Clinical management of alcohol withdrawal: A systematic review

    Directory of Open Access Journals (Sweden)

    Shivanand Kattimani

    2013-01-01

    Full Text Available Alcohol withdrawal is commonly encountered in general hospital settings. It forms a major part of referrals received by a consultation-liaison psychiatrist. This article aims to review the evidence base for appropriate clinical management of the alcohol withdrawal syndrome. We searched Pubmed for articles published in English on pharmacological management of alcohol withdrawal in humans with no limit on the date of publication. Articles not relevant to clinical management were excluded based on the titles and abstract available. Full-text articles were obtained from this list and the cross-references. There were four meta-analyses, 9 systematic reviews, 26 review articles and other type of publications like textbooks. Alcohol withdrawal syndrome is a clinical diagnosis. It may vary in severity. Complicated alcohol withdrawal presents with hallucinations, seizures or delirium tremens. Benzodiazepines have the best evidence base in the treatment of alcohol withdrawal, followed by anticonvulsants. Clinical institutes withdrawal assessment-alcohol revised is useful with pitfalls in patients with medical comorbidities. Evidence favors an approach of symptom-monitored loading for severe withdrawals where an initial dose is guided by risk factors for complicated withdrawals and further dosing may be guided by withdrawal severity. Supportive care and use of vitamins is also discussed.

  9. Strongly correlated perovskite fuel cells

    Science.gov (United States)

    Zhou, You; Guan, Xiaofei; Zhou, Hua; Ramadoss, Koushik; Adam, Suhare; Liu, Huajun; Lee, Sungsik; Shi, Jian; Tsuchiya, Masaru; Fong, Dillon D.; Ramanathan, Shriram

    2016-06-01

    Fuel cells convert chemical energy directly into electrical energy with high efficiencies and environmental benefits, as compared with traditional heat engines. Yttria-stabilized zirconia is perhaps the material with the most potential as an electrolyte in solid oxide fuel cells (SOFCs), owing to its stability and near-unity ionic transference number. Although there exist materials with superior ionic conductivity, they are often limited by their ability to suppress electronic leakage when exposed to the reducing environment at the fuel interface. Such electronic leakage reduces fuel cell power output and the associated chemo-mechanical stresses can also lead to catastrophic fracture of electrolyte membranes. Here we depart from traditional electrolyte design that relies on cation substitution to sustain ionic conduction. Instead, we use a perovskite nickelate as an electrolyte with high initial ionic and electronic conductivity. Since many such oxides are also correlated electron systems, we can suppress the electronic conduction through a filling-controlled Mott transition induced by spontaneous hydrogen incorporation. Using such a nickelate as the electrolyte in free-standing membrane geometry, we demonstrate a low-temperature micro-fabricated SOFC with high performance. The ionic conductivity of the nickelate perovskite is comparable to the best-performing solid electrolytes in the same temperature range, with a very low activation energy. The results present a design strategy for high-performance materials exhibiting emergent properties arising from strong electron correlations.

  10. Frictional Coulomb drag in strong magnetic fields

    DEFF Research Database (Denmark)

    Bønsager, Martin Christian; Flensberg, Karsten; Hu, Ben Yu-Kuang

    1997-01-01

    A treatment of frictional Coulomb drag between two two-dimensional electron layers in a strong perpendicular magnetic field, within the independent electron picture, is presented. Assuming fully resolved Landau levels, the linear response theory expression for the transresistivity rho(21) is eval......A treatment of frictional Coulomb drag between two two-dimensional electron layers in a strong perpendicular magnetic field, within the independent electron picture, is presented. Assuming fully resolved Landau levels, the linear response theory expression for the transresistivity rho(21...

  11. New Drugs of Abuse and Withdrawal Syndromes.

    Science.gov (United States)

    Andrabi, Sara; Greene, Spencer; Moukaddam, Nidal; Moukkadam, Nidal; Li, Benjamin

    2015-11-01

    New drugs of abuse continue to emerge, including synthetic cannabinoids, synthetic cathinones, and hallucinogens. It is important to recognize their individual psychopharmacologic properties, symptoms of intoxication, and symptoms of withdrawal. Providers must be vigilant of acute medical or psychiatric complications that may arise from use of these substances. Treatment of the patient also includes recognition of any substance use disorders as well as comorbid psychiatric disorders. Although pharmacologic treatments for substance use disorder (of the drugs included in this article) are limited, there are a variety of psychotherapeutic modalities that may be of some benefit. Published by Elsevier Inc.

  12. Spontaneous reduction of prolactinoma post cabergoline withdrawal

    Directory of Open Access Journals (Sweden)

    Sampath Kumar Venkatesh

    2012-01-01

    Full Text Available Prolactinomas are common pituitary tumors usually highly responsive to dopamine agonists. Around 70-90% of the prolactinomas exhibit decrease in tumor size, though variably with these agents. Uncommonly, there may be little or no shrinkage in pituitary tumor. In the absence of medical therapy, pituitary apoplexy may also result in tumor shrinkage, albeit rarely. We report here a case showing only modest reduction in prolactinoma with cabergoline given for a period of one and a half years. Surprisingly, this tumor showed a 40% reduction in the tumor size 3 months after cabergoline withdrawal in the absence of clinical or radiological evidence of apoplexy.

  13. Neural mechanisms underlying morphine withdrawal in addicted patients: a review

    Directory of Open Access Journals (Sweden)

    Nima Babhadiashar

    2015-06-01

    Full Text Available Morphine is one of the most potent alkaloid in opium, which has substantial medical uses and needs and it is the first active principle purified from herbal source. Morphine has commonly been used for relief of moderate to severe pain as it acts directly on the central nervous system; nonetheless, its chronic abuse increases tolerance and physical dependence, which is commonly known as opiate addiction. Morphine withdrawal syndrome is physiological and behavioral symptoms that stem from prolonged exposure to morphine. A majority of brain regions are hypofunctional over prolonged abstinence and acute morphine withdrawal. Furthermore, several neural mechanisms are likely to contribute to morphine withdrawal. The present review summarizes the literature pertaining to neural mechanisms underlying morphine withdrawal. Despite the fact that morphine withdrawal is a complex process, it is suggested that neural mechanisms play key roles in morphine withdrawal.

  14. Smartphone Restriction and its Effect on Subjective Withdrawal Related Scores

    OpenAIRE

    Aarestad, Sarah Helene; Eide, Tine Almenning

    2017-01-01

    Smartphone overuse is associated with a number of negative consequences for the individual and the environment. In the right end of the distribution of smartphone usage, concepts such as smartphone addiction seem warranted. An area that so far lacks research concerns the effect of smartphone restriction generally and specifically on subjective withdrawal related scores across different degrees of smartphone usage. The present study examined withdrawal related scores on the Smartphone Withdraw...

  15. Demand-Withdraw Patterns in Marital Conflict in the Home

    OpenAIRE

    Papp, Lauren M.; Kouros, Chrystyna D.; Cummings, E. Mark

    2009-01-01

    The present study extended laboratory-based findings of demand-withdraw communication into marital conflict in the home and further explored its linkages with spousal depression. U.S. couples (N = 116) provided diary reports of marital conflict and rated depressive symptoms. Hierarchical linear modeling results indicated that husband demand-wife withdraw and wife demand-husband withdraw occurred in the home at equal frequency, and both were more likely to occur when discussing topics that con...

  16. Predictors of withdrawal: possible precursors of avoidant personality disorder.

    Science.gov (United States)

    Eggum, Natalie D; Eisenberg, Nancy; Spinrad, Tracy L; Valiente, Carlos; Edwards, Alison; Kupfer, Anne S; Reiser, Mark

    2009-01-01

    Relations of avoidant personality disorder (AvPD) with shyness and inhibition suggest that a precursor of AvPD is withdrawal. Using a sample of 4.5- to 7-year-olds studied four times, 2 years apart, four and three classes of children differing in trajectories of mother- and teacher-reported withdrawal, respectively, were identified. Mothers and teachers generally did not agree on children's trajectories but the pattern of findings in the two contexts did not differ markedly. The mother-identified high and declining withdrawal class, in comparison with less withdrawn classes, and the teacher-identified high and declining class compared with low withdrawal classes, were associated with relatively high levels of anger and low levels of attentional control and resiliency. The mother-identified moderate and increasing withdrawal class was distinguished from less problematic withdrawal classes by higher anger, lower resiliency, and sometimes, lower attentional control. The teacher-identified low and increasing withdrawal class was distinguished from less problematic withdrawal classes by lower resiliency and lower attentional control. Findings are discussed in terms of the developmental precursors to social withdrawal and avoidant behavior.

  17. Withdrawal symptoms in internet gaming disorder: A systematic review.

    Science.gov (United States)

    Kaptsis, Dean; King, Daniel L; Delfabbro, Paul H; Gradisar, Michael

    2016-02-01

    Internet gaming disorder (IGD) is currently positioned in the appendix of the DSM-5 as a condition requiring further study. The aim of this review was to examine the state of current knowledge of gaming withdrawal symptomatology, given the importance of withdrawal in positioning the disorder as a behavioral addiction. A total of 34 studies, including 10 qualitative studies, 17 research reports on psychometric instruments, and 7 treatment studies, were evaluated. The results indicated that the available evidence on Internet gaming withdrawal is very underdeveloped. Internet gaming withdrawal is most consistently referred to as 'irritability' and 'restlessness' following cessation of the activity. There exists a concerning paucity of qualitative studies that provide detailed clinical descriptions of symptoms arising from cessation of internet gaming. This has arguably compromised efforts to quantify withdrawal symptoms in empirical studies of gaming populations. Treatment studies have not reported on the natural course of withdrawal and/or withdrawal symptom trajectory following intervention. It is concluded that many more qualitative clinical studies are needed, and should be prioritised, to develop our understanding of gaming withdrawal. This should improve clinical descriptions of problematic internet gaming and in turn improve the quantification of IGD withdrawal and thus treatments for harmful internet gaming. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. [Alcohol withdrawal syndrome dynamics during treatment with nooclerin (deanoli aceglumas)].

    Science.gov (United States)

    Agibalova, T V; Buzik, O Zh; Rychkova, O V; Smyshlyaev, A V; Rumbesht, V V

    2018-01-01

    To study the efficacy of nooclerin (deanoli aceglumas) in alcohol withdrawal syndrome assessed by clinical and biochemical characteristics. A multicenter, open, randomized, comparative study of nooclerin in the complex treatment of alcohol withdrawal syndrome included 90 patients. The patients were randomized into nooclerin group (n=55) and control group (n=35). Nooclerin reduced alcohol withdrawal symptoms more significantly throughout the whole study period. There were significant between-group differences on the Clinical Institute Withdrawal Assessment of Alcohol Scale (CIWA-Ar) and the Multidimensional Fatigue Inventory (МFI-20). However, patients exhibited no excessive activity. No adverse side-effects were observed.

  19. The Non-Proliferation Treaty and the Withdrawal Clause

    International Nuclear Information System (INIS)

    Boutherin, Gregory

    2008-01-01

    Like any international agreement, the NPT includes a withdrawal clause. The North Korean withdrawal, which was announced in 1993 and became effective in 2003, shows how difficult it is to preserve this possibility, while guaranteeing compliance with signed agreements. To achieve this target, two conditions are required: first, enhancing the means by which the reasons for withdrawals can be made clear and second, to allow the Security Council to draw all the consequences of withdrawals that could imply that a treaty has been violated

  20. Strong ligand field effects of blue phosphorescent mono-cyclometalated iridium(III) complexes

    International Nuclear Information System (INIS)

    Ham, Ho Wan; Jung, Kyung Yoon; Kim, Young Sik

    2010-01-01

    A series of mono-cyclometalated blue phosphorescent iridium(III) complexes with two phosphines trans to each other and two cis-ancillary ligands, such as Ir(F 2 Meppy)(PPhMe 2 ) 2 (H)(Cl), [Ir(F 2 Meppy)(PPhMe 2 ) 2 (H)(NCMe)] + and Ir(F 2 Meppy)(PPhMe 2 ) 2 -(H)(CN), [F 2 Meppy = 2-(2',4'-difluorophenyl)-4-methyl-pyridine] were synthesized and studied to tune the phosphorescence wavelength to the deep blue region and to enhance the luminescence efficiencies. We investigate the electron-withdrawing capabilities of ancillary ligands using the DFT and TD-DFT calculations on the ground and excited states of the three complexes to gain insight into the factors responsible for the emission color change and the different luminescence efficiency. Reducing the molecular weight of phosphine ligand with PPhMe 2 leads to a strategy of the efficient deep blue organic light-emitting devices (OLED) by thermal processing instead of the solution processing. The electron-withdrawing difluoro group substituted on the phenyl ring and the cyano strong field ancillary ligand in the trans position to the carbon atom of phenyl ring increased HOMO-LUMO gap and achieved the hypsochromic shift in emission color. As a result, the maximum emission spectra of Ir(F 2 Meppy)(PPhMe 2 ) 2 (H)(Cl), [Ir(F 2 Meppy)(PPhMe 2 ) 2 (H)-(NCMe)] + and Ir(F 2 Meppy)(PPh-Me 2 ) 2 (H)(CN) were in the ranges of 446, 440, 439 nm, respectively.

  1. Strong ligand field effects of blue phosphorescent mono-cyclometalated iridium(III) complexes

    Energy Technology Data Exchange (ETDEWEB)

    Ham, Ho Wan [Department of Information Display, Hongik University, Seoul, 121-791 (Korea, Republic of); Jung, Kyung Yoon [International Design School for Advanced Studies, Hongik University, Seoul 121-791 (Korea, Republic of); Kim, Young Sik, E-mail: youngkim@hongik.ac.k [Department of Information Display, Hongik University, Seoul, 121-791 (Korea, Republic of)

    2010-09-01

    A series of mono-cyclometalated blue phosphorescent iridium(III) complexes with two phosphines trans to each other and two cis-ancillary ligands, such as Ir(F{sub 2}Meppy)(PPhMe{sub 2}){sub 2}(H)(Cl), [Ir(F{sub 2}Meppy)(PPhMe{sub 2}){sub 2}(H)(NCMe)]{sup +} and Ir(F{sub 2}Meppy)(PPhMe{sub 2}){sub 2}-(H)(CN), [F{sub 2}Meppy = 2-(2',4'-difluorophenyl)-4-methyl-pyridine] were synthesized and studied to tune the phosphorescence wavelength to the deep blue region and to enhance the luminescence efficiencies. We investigate the electron-withdrawing capabilities of ancillary ligands using the DFT and TD-DFT calculations on the ground and excited states of the three complexes to gain insight into the factors responsible for the emission color change and the different luminescence efficiency. Reducing the molecular weight of phosphine ligand with PPhMe{sub 2} leads to a strategy of the efficient deep blue organic light-emitting devices (OLED) by thermal processing instead of the solution processing. The electron-withdrawing difluoro group substituted on the phenyl ring and the cyano strong field ancillary ligand in the trans position to the carbon atom of phenyl ring increased HOMO-LUMO gap and achieved the hypsochromic shift in emission color. As a result, the maximum emission spectra of Ir(F{sub 2}Meppy)(PPhMe{sub 2}){sub 2}(H)(Cl), [Ir(F{sub 2}Meppy)(PPhMe{sub 2}){sub 2}(H)-(NCMe)]{sup +} and Ir(F{sub 2}Meppy)(PPh-Me{sub 2}){sub 2} (H)(CN) were in the ranges of 446, 440, 439 nm, respectively.

  2. Withdrawal rates as a consequence of disclosure of risk associated with manipulation of the cervical spine

    Directory of Open Access Journals (Sweden)

    Forrest Lianne

    2010-10-01

    Full Text Available Abstract Background The risk associated with cervical manipulation is controversial. Research in this area is widely variable but as yet the risk is not easily quantifiable. This presents a problem when informing the patient of risks when seeking consent and information may be withheld due to the fear of patient withdrawal from care. As yet, there is a lack of research into the frequency of risk disclosure and consequent withdrawal from manipulative treatment as a result. This study seeks to investigate the reality of this and to obtain insight into the attitudes of chiropractors towards informed consent and disclosure. Methods Questionnaires were posted to 200 UK chiropractors randomly selected from the register of the General Chiropractic Council. Results A response rate of 46% (n = 92 was achieved. Thirty-three per cent (n = 30 respondents were female and the mean number of years in practice was 10. Eighty-eight per cent considered explanation of the risks associated with any recommended treatment important when obtaining informed consent. However, only 45% indicated they always discuss this with patients in need of cervical manipulation. When asked whether they believed discussing the possibility of a serious adverse reaction to cervical manipulation could increase patient anxiety to the extent there was a strong possibility the patient would refuse treatment, 46% said they believed this could happen. Nonetheless, 80% said they believed they had a moral/ethical obligation to disclose risk associated with cervical manipulation despite these concerns. The estimated number of withdrawals throughout respondents' time in practice was estimated at 1 patient withdrawal for every 2 years in practice. Conclusion The withdrawal rate from cervical manipulation as a direct consequence of the disclosure of associated serious risks appears unfounded. However, notwithstanding legal obligations, reluctance to disclose risk due to fear of increasing patient

  3. Electron/electron acoustic instability

    International Nuclear Information System (INIS)

    Gary, S.P.

    1987-01-01

    The electron acoustic wave becomes a normal mode of an unmagnetized collisionless plasma in the presence of two electron components with similar densities, but strongly disparate temperatures. The characteristic frequency of this mode is the plasma frequency of the cooler electron component. If these two electron components have a relative drift speed several times the thermal speed of the cooler component, the electron/electron acoustic instability may arise. This paper describes the parametric dependences of the threshold drift speed and maximum growth rate of this instability, and compares these with the same properties of the electron/ion acoustic instability. Under the condition of zero current, the electron/ion acoustic instability typically has the lower threshold drift speed, so that observation of the electron/electron acoustic instability is a strong indication of the presence of an electrical current in the plasma

  4. Abortion: Strong's counterexamples fail

    DEFF Research Database (Denmark)

    Di Nucci, Ezio

    2009-01-01

    This paper shows that the counterexamples proposed by Strong in 2008 in the Journal of Medical Ethics to Marquis's argument against abortion fail. Strong's basic idea is that there are cases--for example, terminally ill patients--where killing an adult human being is prima facie seriously morally...

  5. Strong Langmuir turbulence

    International Nuclear Information System (INIS)

    Goldman, M.V.

    1984-01-01

    After a brief discussion of beam-excited Langmuir turbulence in the solar wind, we explain the criteria for wave-particle, three-wave and strong turbulence interactions. We then present the results of a numerical integration of the Zakharov equations, which describe the strong turbulence saturation of a weak (low-density) high energy, bump-on-tail beam instability. (author)

  6. Nicotine Withdrawal Disrupts Contextual Learning but Not Recall of Prior Contextual Associations: Implications for Nicotine Addiction

    OpenAIRE

    Portugal, George S.; Gould, Thomas J.

    2008-01-01

    Interactions between nicotine and learning could contribute to nicotine addiction. Although previous research indicates that nicotine withdrawal disrupts contextual learning, the effects of nicotine withdrawal on contextual memories acquired before withdrawal are unknown. The present study investigated whether nicotine withdrawal disrupted recall of prior contextual memories by examining the effects of nicotine withdrawal on recall of nicotine conditioned place preference (CPP) and contextual...

  7. Electron detector

    International Nuclear Information System (INIS)

    Hashimoto, H.; Mogami, A.

    1975-01-01

    A device for measuring electron densities at a given energy level in an electron beam or the like having strong background noise, for example, in the detection of Auger electric energy spectrums is described. An electron analyzer passes electrons at the given energy level and at the same time electrons of at least one adjacent energy level. Detecting means associated therewith produce signals indicative of the densities of the electrons at each energy level and combine these signals to produce a signal indicative of the density of the electrons of the given energy level absent background noise

  8. 12 CFR 563g.11 - Withdrawal or abandonment.

    Science.gov (United States)

    2010-01-01

    ... 12 Banks and Banking 5 2010-01-01 2010-01-01 false Withdrawal or abandonment. 563g.11 Section 563g.11 Banks and Banking OFFICE OF THRIFT SUPERVISION, DEPARTMENT OF THE TREASURY SECURITIES OFFERINGS § 563g.11 Withdrawal or abandonment. (a) Any offering circular, amendment, or exhibit may be withdrawn...

  9. 5 CFR 831.1207 - Withdrawal of disability retirement applications.

    Science.gov (United States)

    2010-01-01

    ... type. (d) OPM also considers a disability retirement application to be withdrawn when the agency... 5 Administrative Personnel 2 2010-01-01 2010-01-01 false Withdrawal of disability retirement...) CIVIL SERVICE REGULATIONS (CONTINUED) RETIREMENT Disability Retirement § 831.1207 Withdrawal of...

  10. 49 CFR 450.16 - Withdrawal of delegation.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 6 2010-10-01 2010-10-01 false Withdrawal of delegation. 450.16 Section 450.16... SECURITY SAFETY APPROVAL OF CARGO CONTAINERS GENERAL Procedure for Delegation to Approval Authorities § 450.16 Withdrawal of delegation. (a) The Chief, Office of Operating and Environmental Standards (CG-522...

  11. Social Withdrawal, Friendship, and Depressed Mood in Adolescents

    NARCIS (Netherlands)

    Aleva, A.E.|info:eu-repo/dai/nl/141299789; van Beek, Y.|info:eu-repo/dai/nl/107292300

    2017-01-01

    Social withdrawal in children may develop into a depressed mood in early adolescence , through experiences of problematic peer relationships, while friendship may function as a buffer (Rubin, Coplan, & Bowker, 2009). Our study examines the predictive relation between social withdrawal and depressive

  12. 20 CFR 410.232 - Withdrawal of a claim.

    Science.gov (United States)

    2010-04-01

    ... 20 Employees' Benefits 2 2010-04-01 2010-04-01 false Withdrawal of a claim. 410.232 Section 410.232 Employees' Benefits SOCIAL SECURITY ADMINISTRATION FEDERAL COAL MINE HEALTH AND SAFETY ACT OF 1969... Claims and Evidence § 410.232 Withdrawal of a claim. (a) Before adjudication of claim. A claimant (or an...

  13. 20 CFR 410.690 - Withdrawal of charges.

    Science.gov (United States)

    2010-04-01

    ... 20 Employees' Benefits 2 2010-04-01 2010-04-01 false Withdrawal of charges. 410.690 Section 410.690 Employees' Benefits SOCIAL SECURITY ADMINISTRATION FEDERAL COAL MINE HEALTH AND SAFETY ACT OF 1969... Review, Finality of Decisions, and Representation of Parties § 410.690 Withdrawal of charges. If an...

  14. Trajectories of Social Withdrawal from Middle Childhood to Early Adolescence

    Science.gov (United States)

    Oh, Wonjung; Rubin, Kenneth H.; Bowker, Julie C.; Booth-LaForce, Cathryn; Rose-Krasnor, Linda; Laursen, Brett

    2008-01-01

    Heterogeneity and individual differences in the developmental course of social withdrawal were examined longitudinally in a community sample (N = 392). General Growth Mixture Modeling (GGMM) was used to identify distinct pathways of social withdrawal, differentiate valid subgroup trajectories, and examine factors that predicted change in…

  15. 27 CFR 19.997 - Withdrawal of fuel alcohol.

    Science.gov (United States)

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Withdrawal of fuel alcohol. 19.997 Section 19.997 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU... and Transfers § 19.997 Withdrawal of fuel alcohol. For each shipment or other removal of fuel alcohol...

  16. Effect of Potassium Channel Modulators on Morphine Withdrawal in Mice

    Directory of Open Access Journals (Sweden)

    Vikas Seth

    2010-01-01

    Full Text Available The present study was conducted to investigate the effect of potassium channel openers and blockers on morphine withdrawal syndrome. Mice were rendered dependent on morphine by subcutaneous injection of morphine; four hours later, withdrawal was induced by using an opioid antagonist, naloxone. Mice were observed for 30 minutes for the withdrawal signs ie, the characteristic jumping, hyperactivity, urination and diarrhea. ATP-dependent potassium (K + ATP channel modulators were injected intraperitoneally (i.p. 30 minutes before the naloxone. It was found that a K + ATP channel opener, minoxidil (12.5–50 mg/kg i.p., suppressed the morphine withdrawal significantly. On the other hand, the K + ATP channel blocker glibenclamide (12.5–50 mg/kg i.p. caused a significant facilitation of the withdrawal. Glibenclamide was also found to abolish the minoxidil's inhibitory effect on morphine withdrawal. The study concludes that K + ATP channels play an important role in the genesis of morphine withdrawal and K + ATP channel openers could be useful in the management of opioid withdrawal. As morphine opens K + ATP channels in neurons, the channel openers possibly act by mimicking the effects of morphine on neuronal K + currents.

  17. 40 CFR 180.8 - Withdrawal of petitions without prejudice.

    Science.gov (United States)

    2010-07-01

    ... prejudice. 180.8 Section 180.8 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED... § 180.8 Withdrawal of petitions without prejudice. In some cases the Administrator will notify the... clarification or the obtaining of additional data. This withdrawal may be without prejudice to a future filing...

  18. Monitoring device for withdrawing control rods

    International Nuclear Information System (INIS)

    Higashigawa, Yuichi.

    1985-01-01

    Purpose: To improve the sensitivity and the responsivity to an equivalent extent to those in the case where local power range monitors are densely arranged near each of the control rods, with no actual but pseudo increase of the number of local power range monitors. Constitution: The monitor arrangement is patterned by utilizing the symmetricity of the reactor core and stored in a monitor designating device. The symmetricity of control rods to be selected and withdrawn by an operator is judged by a control rod symmetry monitoring device, while the symmetricity of the withdrawn control rods is judged by a control rod withdrawal state monitoring device. Then, only when both of the devices judge the symmetricity, the control rods are subjected to gang driving by the control rod drive mechanisms. In this way, monitoring at a high sensitivity and responsivity is enabled with no increase for the number of monitors. (Yoshino, Y.)

  19. Clinical Manifestations of the Opiate Withdrawal Syndrome

    Directory of Open Access Journals (Sweden)

    Faniya Shigakova

    2015-09-01

    Full Text Available Currently, substance abuse is one of the most serious problems facing our society. The aim of this study was to investigate the clinical manifestations of the opiate withdrawal syndrome (OWS. The study included 112 patients (57 women and 55 men aged from 18 to 64 years with opium addiction according to the DSM-IV. To study the clinical manifestation of OWS, the special 25-score scale with four sections to assess severity of sleep disorders, pain syndrome, autonomic disorders, and affective symptoms was used. Given the diversity of the OWS symptoms, attention was focused on three clinical variants, affective, algic and mixed. The OWS affective variant was registered more frequently in women, while the mixed type of OWS was more typical of men.

  20. Bulimic symptoms and the social withdrawal syndrome.

    Science.gov (United States)

    Rotenberg, Ken J; Bharathi, Carla; Davies, Helen; Finch, Tom

    2013-08-01

    One hundred and thirty-seven undergraduates (81 females; mean age = 21 years-10 months) completed the Bulimic SEDS subscale and standardized measures of trust beliefs in close others (mother, father, and friend), disclosure to them, and loneliness. Structural Equation Modelling yielded: (1) a negative path between Bulimic Symptoms and trust beliefs, (2) a positive path between trust beliefs and disclosure, (3) a negative path between trust beliefs and loneliness, and (4) a negative path between disclosure and loneliness. As expected, trust beliefs statistically mediated the relations between Bulimic Symptoms and both disclosure and loneliness and disclosure statistically mediated the relation between trust beliefs and loneliness. The findings supported the conclusion that individuals with bulimia nervosa are prone to the social withdrawal syndrome comprising a coherent and integrated pattern of low trust beliefs in close others, low disclosure to close others, and high loneliness. Copyright © 2013 Elsevier Ltd. All rights reserved.

  1. Withdrawal of cerivastatin from the world market

    Directory of Open Access Journals (Sweden)

    Pitt Bertram

    2001-09-01

    Full Text Available Abstract Cerivastatin was recently withdrawn from the market because of 52 deaths attributed to drug-related rhabdomyolysis that lead to kidney failure. The risk was found to be higher among patients who received the full dose (0.8 mg/day and those who received gemfibrozil concomitantly. Rhabdomyolysis was 10 times more common with cerivastatin than the other five approved statins. We address three important questions raised by this withdrawal. Should we continue to approve drugs on surrogate efficacy? Are all statins interchangeable? Do the benefits outweigh the risks of statins? We conclude that decisions regarding the use of drugs should be based on direct evidence from long-term clinical outcome trials.

  2. Strong intrinsic motivation

    OpenAIRE

    Dessi, Roberta; Rustichini, Aldo

    2015-01-01

    A large literature in psychology, and more recently in economics, has argued that monetary rewards can reduce intrinsic motivation. We investigate whether the negative impact persists when intrinsic motivation is strong, and test this hypothesis experimentally focusing on the motivation to undertake interesting and challenging tasks, informative about individual ability. We find that this type of task can generate strong intrinsic motivation, that is impervious to the effect of monetary incen...

  3. Bitcoin Meets Strong Consistency

    OpenAIRE

    Decker, Christian; Seidel, Jochen; Wattenhofer, Roger

    2014-01-01

    The Bitcoin system only provides eventual consistency. For everyday life, the time to confirm a Bitcoin transaction is prohibitively slow. In this paper we propose a new system, built on the Bitcoin blockchain, which enables strong consistency. Our system, PeerCensus, acts as a certification authority, manages peer identities in a peer-to-peer network, and ultimately enhances Bitcoin and similar systems with strong consistency. Our extensive analysis shows that PeerCensus is in a secure state...

  4. Strong gravity and supersymmetry

    International Nuclear Information System (INIS)

    Chamseddine, Ali H.; Salam, A.; Strathdee, J.

    1977-11-01

    A supersymmetric theory is constructed for a strong f plus a weak g graviton, together with their accompanying massive gravitinos, by gaugin the gradel 0Sp(2,2,1)x 0Sp(2,2,1) structure. The mixing term between f and g fields, which makes the strong graviton massive, can be introduced through a spontaneous symmetry-breaking mechanism implemented in this note by constructing a non-linear realization of the symmetry group

  5. Why withdrawal from the European Union is undemocratic

    DEFF Research Database (Denmark)

    Olsen, Tore Vincents; Rostbøll, Christian F.

    2017-01-01

    The Lisbon Treaty from 2009 introduced the possibility for individual member states to withdraw from the European Union (EU) on the basis of a unilateral decision. In June 2016 the UK decided to leave the EU invoking article 50 of the treaty. But is withdrawal democratically legitimate? In fact......, the all affected principle suggests that it is undemocratic for subunits to leave larger political units when it adversely affects other citizens without including them in the decision. However, it is unclear what the currency of this affectedness is and, hence, why withdrawal would be undemocratic. We...... argue that it is the effect of withdrawal on the status of citizens as free and equal that is decisive and that explains why unilateral withdrawal of subunits from larger units is democratically illegitimate. Moreover, on the ‘all affected status principle’ that we develop, even multilaterally agreed...

  6. Demand-Withdraw Patterns in Marital Conflict in the Home.

    Science.gov (United States)

    Papp, Lauren M; Kouros, Chrystyna D; Cummings, E Mark

    2009-06-01

    The present study extended laboratory-based findings of demand-withdraw communication into marital conflict in the home and further explored its linkages with spousal depression. U.S. couples (N = 116) provided diary reports of marital conflict and rated depressive symptoms. Hierarchical linear modeling results indicated that husband demand-wife withdraw and wife demand-husband withdraw occurred in the home at equal frequency, and both were more likely to occur when discussing topics that concerned the marital relationship. For both patterns, conflict initiator was positively linked to the demander role. Accounting for marital satisfaction, both demand-withdraw patterns predicted negative emotions and tactics during marital interactions and lower levels of conflict resolution. Spousal depression was linked to increased likelihood of husband demand-wife withdraw.

  7. Opiate Withdrawal Complicated by Tetany and Cardiac Arrest

    Directory of Open Access Journals (Sweden)

    Irfanali R. Kugasia

    2014-01-01

    Full Text Available Patients with symptoms of opiate withdrawal, after the administration of opiate antagonist by paramedics, are a common presentation in the emergency department of hospitals. Though most of opiate withdrawal symptoms are benign, rarely they can become life threatening. This case highlights how a benign opiate withdrawal symptom of hyperventilation led to severe respiratory alkalosis that degenerated into tetany and cardiac arrest. Though this patient was successfully resuscitated, it is imperative that severe withdrawal symptoms are timely identified and immediate steps are taken to prevent catastrophes. An easier way to reverse the severe opiate withdrawal symptom would be with either low dose methadone or partial opiate agonists like buprenorphine. However, if severe acid-base disorder is identified, it would be safer to electively intubate these patients for better control of their respiratory and acid-base status.

  8. Acute coronary ischemia during alcohol withdrawal: a case report

    Directory of Open Access Journals (Sweden)

    Sriram Ganeshalingam

    2011-08-01

    Full Text Available Abstract Introduction The potential of alcohol withdrawal to cause acute coronary events is an area that needs the urgent attention of clinicians and researchers. Case presentation We report the case of a 52-year-old heavy-alcohol-using Sri Lankan man who developed electocardiogram changes suggestive of an acute coronary event during alcohol withdrawal. Despite the patient being asymptomatic, subsequent echocardiogram showed evidence of ischemic myocardial dysfunction. We review the literature on precipitation of myocardial ischemia during alcohol withdrawal and propose possible mechanisms. Conclusions Alcohol withdrawal is a commonly observed phenomenon in hospitals. However, the number of cases reported in the literature of acute coronary events occurring during withdrawal is few. Many cases of acute ischemia or sudden cardiac deaths may be attributed to other well known complications of delirium tremens. This is an area needing the urgent attention of clinicians and epidemiologists.

  9. Neurobiology of opioid withdrawal: Role of the endothelin system.

    Science.gov (United States)

    Bhalla, Shaifali; Andurkar, Shridhar V; Gulati, Anil

    2016-08-15

    Morphine and oxycodone are potent opioid analgesics most commonly used for the management of moderate to severe acute and chronic pain. Their clinical utility is limited by undesired side effects like analgesic tolerance, dependence, and withdrawal. We have previously demonstrated that endothelin-A (ETA) receptor antagonists potentiate opioid analgesia and eliminate analgesic tolerance. Mechanistically, G proteins and regulatory proteins such as β-arrestins have shown to play an important role in mediating opioid tolerance, dependence, and withdrawal. Recently, the involvement of central ET mechanisms in opioid withdrawal was investigated. ETA receptor antagonist was shown to block majority of the signs and symptoms associated with opioid withdrawal. This review focuses on ET as one of the potential novel strategies to manage the challenge of opioid withdrawal. An overview of additional players in this process (G proteins and β-arrestin2), and the possible therapeutic implications of these findings are presented. Copyright © 2016 Elsevier Inc. All rights reserved.

  10. Nicotine Withdrawal Induces Neural Deficits in Reward Processing.

    Science.gov (United States)

    Oliver, Jason A; Evans, David E; Addicott, Merideth A; Potts, Geoffrey F; Brandon, Thomas H; Drobes, David J

    2017-06-01

    Nicotine withdrawal reduces neurobiological responses to nonsmoking rewards. Insight into these reward deficits could inform the development of targeted interventions. This study examined the effect of withdrawal on neural and behavioral responses during a reward prediction task. Smokers (N = 48) attended two laboratory sessions following overnight abstinence. Withdrawal was manipulated by having participants smoke three regular nicotine (0.6 mg yield; satiation) or very low nicotine (0.05 mg yield; withdrawal) cigarettes. Electrophysiological recordings of neural activity were obtained while participants completed a reward prediction task that involved viewing four combinations of predictive and reward-determining stimuli: (1) Unexpected Reward; (2) Predicted Reward; (3) Predicted Punishment; (4) Unexpected Punishment. The task evokes a medial frontal negativity that mimics the phasic pattern of dopaminergic firing in ventral tegmental regions associated with reward prediction errors. Nicotine withdrawal decreased the amplitude of the medial frontal negativity equally across all trial types (p nicotine dependence (p Nicotine withdrawal had equivocal impact across trial types, suggesting reward processing deficits are unlikely to stem from changes in phasic dopaminergic activity during prediction errors. Effects on tonic activity may be more pronounced. Pharmacological interventions directly targeting the dopamine system and behavioral interventions designed to increase reward motivation and responsiveness (eg, behavioral activation) may aid in mitigating withdrawal symptoms and potentially improving smoking cessation outcomes. Findings from this study indicate nicotine withdrawal impacts reward processing signals that are observable in smokers' neural activity. This may play a role in the subjective aversive experience of nicotine withdrawal and potentially contribute to smoking relapse. Interventions that address abnormal responding to both pleasant and

  11. Withdrawing to a Virtual World: Associations between Subtypes of Withdrawal, Media Use, and Maladjustment in Emerging Adults

    Science.gov (United States)

    Nelson, Larry J.; Coyne, Sarah M.; Howard, Emily; Clifford, Brandon N.

    2016-01-01

    An approach-avoidance model of social withdrawal (Asendorpf, 1990) identifies 3 types of social withdrawal including shyness, unsociability, and avoidance. Each appears to be uniquely associated with varying indicators of maladjustment in emerging adulthood (Nelson, 2013) but little, if any, work has been done to see how they might be linked to…

  12. Psychosocial withdrawal characteristics of nicotine compared with alcohol and caffeine.

    Science.gov (United States)

    Miyata, Hisatsugu; Hironaka, Naoyuki; Takada, Kohji; Miyasato, Katsumasa; Nakamura, Koichi; Yanagita, Tomoji

    2008-10-01

    The purpose of the present study was to observe the psychosocial characteristics of withdrawal from cigarette smoking in comparison with those from caffeine (CAF) and alcoholic (ALC) beverage withdrawal. Twenty-seven healthy volunteers at a medial level of dependence on both cigarettes (nicotine, NCT) and either CAF or ALC, as judged by the DSM-IV-TR criteria for substance dependence, participated in this study. The participants were required to abstain from smoking and either CAF or ALC for 7 days, each one after another, with a 7-day interval. The order of abstinence was counterbalanced among the participants. Psychosocial parameters, including a desire for substances, social activity function, well-being, withdrawal symptoms, and vital signs, were assessed during the withdrawal periods. The study protocol was approved by the Jikei University Review Board. The results indicated that there were no differences in the maximum level of desire for a substance and the influence on social activity function between NCT and other substances during the withdrawal periods. As for withdrawal symptoms, NCT caused a more intensive degree of irritability than CAF or ALC, and a more intensive degree of difficulty concentrating and restlessness than did withdrawal from ALC. However, the subjective well-being questionnaire indicated no differences in these symptoms between NCT and other substances. The present results suggest that there are no significant differences in psychosocial manifestations regarding the difficulty in abstaining from NCT, CAF, and ALC.

  13. Cannabis Withdrawal in Adults With Attention-Deficit/Hyperactivity Disorder.

    Science.gov (United States)

    Chauchard, Emeline; Hartwell, Karen J; McRae-Clark, Aimee L; Sherman, Brian J; Gorelick, David A

    2018-02-22

    Cannabis withdrawal has not been studied in adults with attention-deficit/hyperactivity disorder (ADHD) who have high rates of cannabis use. We aimed to describe cannabis withdrawal, motivations to quit, and strategies to quit cannabis use in cannabis-dependent adults with ADHD. Twenty-three adults with ADHD enrolled in a controlled clinical trial of pharmacotherapy (atomoxetine) for cannabis dependence (DSM-IV criteria) completed the Marijuana Quit Questionnaire (MJQQ) to provide information on their "most serious" quit attempt made without formal treatment. The study was conducted between November 2005 and June 2008. Participants were predominantly male (82.6%, n = 19), with a mean (SD) age of 27.4 (8.5) years (range, 18-53) at the start of their index quit attempt. The most common motive for quitting cannabis was "to save money" (87%, n = 20); the most common strategy to maintain abstinence was "stopped associating with people who smoke marijuana" (43%, n = 10). Almost all (96%, n = 22) subjects reported ≥ 1 cannabis withdrawal symptom; 7 (30%) met DSM-5 diagnostic criteria for cannabis withdrawal syndrome. Participants with comorbid ADHD and cannabis dependence reported withdrawal symptoms similar to other samples of non-treatment-seeking cannabis-dependent adults with no psychiatric comorbidity. These findings suggest that ADHD does not influence cannabis withdrawal in the way that it does tobacco (nicotine) withdrawal. Data used in this secondary analysis came from ClinicalTrials.gov identifier: NCT00360269. © Copyright 2018 Physicians Postgraduate Press, Inc.

  14. Effect of Morphine Withdrawal Syndrome on Cerebral Ischemia

    Directory of Open Access Journals (Sweden)

    Mohammad Allahtavakoli

    2011-01-01

    Full Text Available Objective(sOpioid abuse is still remained a major mental health problem, a criminal legal issue and may cause ischemic brain changes including stroke and brain edema. In the present study, we investigated whether spontaneously withdrawal syndrome might affect stroke outcomes.Materials and MethodsAddiction was induced by progressive incremental doses of morphine over 7 days. Behavioral signs of withdrawal were observed 24, 48 and 72 hr after morphine deprivation and total withdrawal score was determined. Cerebral ischemia was induced 18-22 hr after the last morphine injection by placing a natural clot into the middle cerebral artery (MCA. Neurological deficits were evaluated at 2, 24 and 48 hr after ischemia induction, and infarct size and brain edema were determined at 48 hr after stroke.ResultsMorphine withdrawal animals showed a significant increase in total withdrawal score and decrease of weight gain during the 72 hr after the last morphine injection. Compared to the addicted and control animals, infarct volume and brain edema were significantly increased in the morphine deprived animals (P< 0.05 at 48 hr after cerebral ischemia. Also, neurological deficits were higher in the morphine-withdrawn rats at 48 hr after stroke (P< 0.05. ConclusionOur data indicates that spontaneous withdrawal syndrome may worsen stroke outcomes. Further investigations are necessary to elucidate mechanisms of opiate withdrawal syndrome on stroke.

  15. Mitragynine attenuates withdrawal syndrome in morphine-withdrawn zebrafish.

    Directory of Open Access Journals (Sweden)

    Beng-Siang Khor

    Full Text Available A major obstacle in treating drug addiction is the severity of opiate withdrawal syndrome, which can lead to unwanted relapse. Mitragynine is the major alkaloid compound found in leaves of Mitragyna speciosa, a plant widely used by opiate addicts to mitigate the harshness of drug withdrawal. A series of experiments was conducted to investigate the effect of mitragynine on anxiety behavior, cortisol level and expression of stress pathway related genes in zebrafish undergoing morphine withdrawal phase. Adult zebrafish were subjected to two weeks chronic morphine exposure at 1.5 mg/L, followed by withdrawal for 24 hours prior to tests. Using the novel tank diving tests, we first showed that morphine-withdrawn zebrafish display anxiety-related swimming behaviors such as decreased exploratory behavior and increased erratic movement. Morphine withdrawal also elevated whole-body cortisol levels, which confirms the phenotypic stress-like behaviors. Exposing morphine-withdrawn fish to mitragynine however attenuates majority of the stress-related swimming behaviors and concomitantly lower whole-body cortisol level. Using real-time PCR gene expression analysis, we also showed that mitragynine reduces the mRNA expression of corticotropin releasing factor receptors and prodynorphin in zebrafish brain during morphine withdrawal phase, revealing for the first time a possible link between mitragynine's ability to attenuate anxiety during opiate withdrawal with the stress-related corticotropin pathway.

  16. [The effect of palonosetron on rocuronium-induced withdrawal movement].

    Science.gov (United States)

    Park, Ki-Bum; Jeon, Younghoon; Yi, Junggu; Kim, Ji-Hyun; Chung, Seung-Yeon; Kwak, Kyung-Hwa

    Rocuronium causes pain and withdrawal movement during induction of anesthesia. In this study, palonosetron was investigated to have analgesic effect on the reduction of rocuronium-induced withdrawal movement. 120 patients were randomly assigned to one of three groups to receive either saline, lidocaine 20mg, or palonosetron 0.075mg with a tourniquet applied two minutes before thiopental sodium (5mg.kg -1 ) was given intravenously. After loss of consciousness, rocuronium (0.6mg.kg -1 ) was injected and the withdrawal movement was estimated by 4-point scale in a double-blind manner. The overall incidence of rocuronium withdrawal movement was 50% with lidocaine (p=0.038), 38% with palonosetron (p=0.006) compared with 75% for saline. The incidence of no pain to mild pain was significantly lower in the lidocaine and palonosetron groups (85% and 92% respectively) than in the saline group (58%). However, there was no significant difference in withdrawal movement between the lidocaine and palonosetron groups. There was no severe movement with palonosetron. Pretreatment of palonosetron with venous occlusion may attenuate rocuronium-induced withdrawal movement as effective as the use of lidocaine. It suggested that peripheral action of palonosetron was effective to reduce rocuronium-induced withdrawal movement. Copyright © 2016. Publicado por Elsevier Editora Ltda.

  17. Opioid withdrawal signs and symptoms in children: frequency and determinants.

    Science.gov (United States)

    Fisher, Deborah; Grap, Mary Jo; Younger, Janet B; Ameringer, Suzanne; Elswick, R K

    2013-01-01

    The purpose of this study was to, in a pediatric population, describe the frequency of opioid withdrawal signs and symptoms and to identify factors associated with these opioid withdrawal signs and symptoms. Opioids are used routinely in the pediatric intensive care population for analgesia, sedation, blunting of physiologic responses to stress, and safety. In children, physical dependence may occur in as little as 2-3 days of continuous opioid therapy. Once the child no longer needs the opioid, the medications are reduced over time. A prospective, descriptive study was conducted. The sample of 26 was drawn from all patients, ages 2 weeks to 21 years admitted to the Children's Hospital of Richmond pediatric intensive care unit (PICU) and who have received continuous infusion or scheduled opioids for at least 5 days. Data collected included: opioid withdrawal score (WAT-1), opioid taper rate (total dose of opioid per day in morphine equivalents per kilogram [MEK]), pretaper peak MEK, pretaper cumulative MEK, number of days of opioid exposure prior to taper, and age. Out of 26 enrolled participants, only 9 (45%) had opioid withdrawal on any given day. In addition, there was limited variability in WAT-1 scores. The most common symptoms notes were diarrhea, vomit, sweat, and fever. For optimal opioid withdrawal assessments, clinicians should use a validated instrument such as the WAT-1 to measure for signs and symptoms of opioid withdrawal. Further research is indicated to examine risk factors for opioid withdrawal in children. Copyright © 2013 Elsevier Inc. All rights reserved.

  18. Effects of caffeine and caffeine withdrawal on mood and cognitive performance degraded by sleep restriction.

    Science.gov (United States)

    Rogers, Peter J; Heatherley, Susan V; Hayward, Robert C; Seers, Helen E; Hill, Joanne; Kane, Marian

    2005-06-01

    It has been suggested that caffeine is most likely to benefit mood and performance when alertness is low. To measure the effects of caffeine on psychomotor and cognitive performance, mood, blood pressure and heart rate in sleep-restricted participants. To do this in a group of participants who had also been previously deprived of caffeine for 3 weeks, thereby potentially removing the confounding effects of acute caffeine withdrawal. Participants were moderate to moderate-high caffeine consumers who were provided with either decaffeinated tea and/or coffee for 3 weeks (LTW) or regular tea and/or coffee for 3 weeks (overnight caffeine-withdrawn participants, ONW). Then, following overnight caffeine abstinence, they were tested on a battery of tasks assessing mood, cognitive performance, etc. before and after receiving caffeine (1.2 mg/kg) or on another day after receiving placebo. Final analyses were based on 17 long-term caffeine-withdrawn participants (LTW) and 17 ONW participants whose salivary caffeine levels on each test day confirmed probable compliance with the instructions concerning restrictions on consumption of caffeine-containing drinks. Acute caffeine withdrawal (ONW) had a number of negative effects, including impairment of cognitive performance, increased headache, and reduced alertness and clear-headedness. Caffeine (versus placebo) did not significantly improve cognitive performance in LTW participants, although it prevented further deterioration of performance in ONW participants. Caffeine increased tapping speed (but tended to impair hand steadiness), increased blood pressure, and had some effects on mood in both groups. The findings provide strong support for the withdrawal reversal hypothesis. In particular, cognitive performance was found to be affected adversely by acute caffeine withdrawal and, even in the context of alertness lowered by sleep restriction, cognitive performance was not improved by caffeine in the absence of these withdrawal

  19. Modulation of histone deacetylase attenuates naloxone-precipitated opioid withdrawal syndrome.

    Science.gov (United States)

    Rehni, Ashish K; Singh, Nirmal; Rachamalla, Mahesh; Tikoo, Kulbhushan

    2012-06-01

    The present study has been designed to investigate the effect of selective inhibitors of histone deacetylase and/or N-acetyl-Asp-Glu-Val-Asp-al (Ac-DEVD-CHO), a selective interleukin-1β converting enzyme inhibitor, on the development of naloxone-induced opioid withdrawal syndrome both in vitro and in vivo and the effect of histone deacetylase inhibition on histone H3 acetylation in brain. Sub-acute morphine administration followed by a single injection of naloxone (8 mg/kg, i.p.) was used to precipitate opioid withdrawal syndrome in mice. Behavioral observations were made immediately after naloxone treatment. Withdrawal syndrome was quantitatively assessed in terms of withdrawal severity score and frequency of jumping, rearing, fore paw licking and circling. Separately naloxone-induced contraction in morphine-dependent isolated rat ileum was employed as an in vitro model. An isobolographic study design was employed to assess potential synergistic activity between trichostatin A and Ac-DEVD-CHO. Brain histone acetylation status was examined by western blotting. Injection of naloxone precipitated a severe form of abstinence syndrome in morphine-dependent mice along with strong contracture in isolated rat ileum. Administration of tributyrin (1.5, 3 and 6 g/kg, p.o.), trichostatin A (0.3, 1.0 and 3.0 mg/kg, p.o.) and Ac-DEVD-CHO (0.3, 1.0 and 3.0 mg/kg, p.o.) markedly and dose dependently attenuated naloxone-induced morphine withdrawal syndrome in vivo as well as in vitro in rat ileum. Trichostatin A was also observed to exert a synergistic interaction with Ac-DEVD-CHO. Western blot analysis revealed that multiple administration with the effective dose of tributyrin or trichostatin A in the in vivo experiments induced hyperacetylation of histone H3 in the mouse brain. Thus, it is proposed that histone deacetylase activation linked mechanism might be involved in the development of opioid dependence and the precipitation of its withdrawal syndrome.

  20. Strongly interacting Fermi gases

    Directory of Open Access Journals (Sweden)

    Bakr W.

    2013-08-01

    Full Text Available Strongly interacting gases of ultracold fermions have become an amazingly rich test-bed for many-body theories of fermionic matter. Here we present our recent experiments on these systems. Firstly, we discuss high-precision measurements on the thermodynamics of a strongly interacting Fermi gas across the superfluid transition. The onset of superfluidity is directly observed in the compressibility, the chemical potential, the entropy, and the heat capacity. Our measurements provide benchmarks for current many-body theories on strongly interacting fermions. Secondly, we have studied the evolution of fermion pairing from three to two dimensions in these gases, relating to the physics of layered superconductors. In the presence of p-wave interactions, Fermi gases are predicted to display toplogical superfluidity carrying Majorana edge states. Two possible avenues in this direction are discussed, our creation and direct observation of spin-orbit coupling in Fermi gases and the creation of fermionic molecules of 23Na 40K that will feature strong dipolar interactions in their absolute ground state.

  1. A strong comeback

    International Nuclear Information System (INIS)

    Marier, D.

    1992-01-01

    This article presents the results of a financial rankings survey which show a strong economic activity in the independent energy industry. The topics of the article include advisor turnover, overseas banks, and the increase in public offerings. The article identifies the top project finance investors for new projects and restructurings and rankings for lenders

  2. Tobacco withdrawal symptoms mediate motivation to reinstate smoking during abstinence.

    Science.gov (United States)

    Aguirre, Claudia G; Madrid, Jillian; Leventhal, Adam M

    2015-08-01

    Withdrawal-based theories of addiction hypothesize that motivation to reinstate drug use following acute abstinence is mediated by withdrawal symptoms. Experimental tests of this hypothesis in the tobacco literature are scant and may be subject to methodological limitations. This study utilized a robust within-subject laboratory experimental design to investigate the extent to which composite tobacco withdrawal symptomatology level and 3 unique withdrawal components (i.e., low positive affect, negative affect, and urge to smoke) mediated the effect of smoking abstinence on motivation to reinstate smoking. Smokers (≥10 cigarettes per day; N = 286) attended 2 counterbalanced sessions at which abstinence duration was differentially manipulated (1 hr vs. 17 hr). At both sessions, participants reported current withdrawal symptoms and subsequently completed a task in which they were monetarily rewarded proportional to the length of time they delayed initiating smoking, with shorter latency reflecting stronger motivation to reinstate smoking. Abstinence reduced latency to smoking initiation and positive affect and increased composite withdrawal symptom level, urge, and negative affect. Abstinence-induced reductions in latency to initiating smoking were mediated by each withdrawal component, with stronger effects operating through urge. Combined analyses suggested that urge, negative affect, and low positive affect operate through empirically unique mediational pathways. Secondary analyses suggested similar effects on smoking quantity, few differences among specific urge and affect subtypes, and that dependence amplifies some abstinence effects. This study provides the first experimental evidence that within-person variation in abstinence impacts motivation to reinstate drug use through withdrawal. Urge, negative affect, and low positive affect may reflect unique withdrawal-mediated mechanisms underlying tobacco addiction. (c) 2015 APA, all rights reserved).

  3. The cannabis withdrawal syndrome: current insights

    Science.gov (United States)

    Bonnet, Udo; Preuss, Ulrich W

    2017-01-01

    The cannabis withdrawal syndrome (CWS) is a criterion of cannabis use disorders (CUDs) (Diagnostic and Statistical Manual of Mental Disorders – Fifth Edition) and cannabis dependence (International Classification of Diseases [ICD]-10). Several lines of evidence from animal and human studies indicate that cessation from long-term and regular cannabis use precipitates a specific withdrawal syndrome with mainly mood and behavioral symptoms of light to moderate intensity, which can usually be treated in an outpatient setting. Regular cannabis intake is related to a desensitization and downregulation of human brain cannabinoid 1 (CB1) receptors. This starts to reverse within the first 2 days of abstinence and the receptors return to normal functioning within 4 weeks of abstinence, which could constitute a neurobiological time frame for the duration of CWS, not taking into account cellular and synaptic long-term neuroplasticity elicited by long-term cannabis use before cessation, for example, being possibly responsible for cannabis craving. The CWS severity is dependent on the amount of cannabis used pre-cessation, gender, and heritable and several environmental factors. Therefore, naturalistic severity of CWS highly varies. Women reported a stronger CWS than men including physical symptoms, such as nausea and stomach pain. Comorbidity with mental or somatic disorders, severe CUD, and low social functioning may require an inpatient treatment (preferably qualified detox) and post-acute rehabilitation. There are promising results with gabapentin and delta-9-tetrahydrocannabinol analogs in the treatment of CWS. Mirtazapine can be beneficial to treat CWS insomnia. According to small studies, venlafaxine can worsen the CWS, whereas other antidepressants, atomoxetine, lithium, buspirone, and divalproex had no relevant effect. Certainly, further research is required with respect to the impact of the CWS treatment setting on long-term CUD prognosis and with respect to

  4. The cannabis withdrawal syndrome: current insights

    Directory of Open Access Journals (Sweden)

    Bonnet U

    2017-04-01

    Full Text Available Udo Bonnet,1,2 Ulrich W Preuss3,4 1Department of Psychiatry, Psychotherapy and Psychosomatic Medicine, Evangelisches Krankenhaus Castrop-Rauxel, Academic Teaching Hospital of the University of Duisburg-Essen, Castrop-Rauxel, 2Department of Psychiatry and Psychotherapy, Faculty of Medicine, LVR-Hospital Essen, University of Duisburg-Essen, Essen, 3Vitos-Klinik Psychiatrie und Psychotherapie Herborn, Herborn, 4Martin Luther University Halle-Wittenberg, Halle (Saale, Germany Abstract: The cannabis withdrawal syndrome (CWS is a criterion of cannabis use disorders (CUDs (Diagnostic and Statistical Manual of Mental Disorders – Fifth Edition and cannabis dependence (International Classification of Diseases [ICD]-10. Several lines of evidence from animal and human studies indicate that cessation from long-term and regular cannabis use precipitates a specific withdrawal syndrome with mainly mood and behavioral symptoms of light to moderate intensity, which can usually be treated in an outpatient setting. Regular cannabis intake is related to a desensitization and downregulation of human brain cannabinoid 1 (CB1 receptors. This starts to reverse within the first 2 days of abstinence and the receptors return to normal functioning within 4 weeks of abstinence, which could constitute a neurobiological time frame for the duration of CWS, not taking into account cellular and synaptic long-term neuroplasticity elicited by long-term cannabis use before cessation, for example, being possibly responsible for cannabis craving. The CWS severity is dependent on the amount of cannabis used pre-cessation, gender, and heritable and several environmental factors. Therefore, naturalistic severity of CWS highly varies. Women reported a stronger CWS than men including physical symptoms, such as nausea and stomach pain. Comorbidity with mental or somatic disorders, severe CUD, and low social functioning may require an inpatient treatment (preferably qualified detox and

  5. USA Withdrawal from Paris Agreement – What Next?

    OpenAIRE

    Sergey Chestnoy; Dinara Gershinkova

    2017-01-01

    In June 2017, President Trump announced the USA’s withdrawal from the Paris Climate Accord, which had been ratified for less than a year, thanks in large part to the USA. That drastic shift followed the change in residency at the White House. Withdrawing from the Paris Accord presents an interesting topic for analysis. There’s the practical side of the withdrawal procedure as set out in Article 28 of the agreement, not to mention the consequences of US non-participation in address...

  6. Ketogenic Diet suppresses Alcohol Withdrawal Syndrome in Rats

    DEFF Research Database (Denmark)

    Dencker, Ditte; Molander, Anna; Thomsen, Morgane

    2018-01-01

    , we investigated the potential therapeutic benefit of a ketogenic diet in managing alcohol withdrawal symptoms during detoxification. METHODS: Male Sprague Dawley rats fed either ketogenic or regular diets were administered ethanol or water orally, twice daily for 6 days while the diet conditions were...... maintained. Abstinence symptoms were rated 6, 24, 48, and 72 hours after the last alcohol administration. RESULTS: Maintenance on a ketogenic diet caused a significant decrease in the alcohol withdrawal symptoms 'rigidity' and 'irritability'. CONCLUSION: Our preclinical pilot study suggests that a ketogenic...... diet may be a novel approach for treating alcohol withdrawal symptoms in humans. This article is protected by copyright. All rights reserved....

  7. The Treatment of Clozapine-Withdrawal Delirium with Electroconvulsive Therapy

    Directory of Open Access Journals (Sweden)

    Anish Modak

    2017-01-01

    Full Text Available Clozapine, a commonly used atypical antipsychotic, can precipitate a severe withdrawal syndrome. In this report, we describe a case of delirium with catatonic features emerging after the immediate cessation of clozapine subsequent to concerns of developing neuroleptic malignant syndrome. After multiple treatments were found to be inefficacious, electroconvulsive therapy (ECT was initiated, resulting in significant improvement. A literature search revealed six previous cases of clozapine-withdrawal syndromes of varied symptomatology treated with ECT. To our knowledge, the present case represents the first reported clozapine-withdrawal delirium treated successfully with ECT.

  8. Freshmen Program Withdrawal: Types and Recommendations

    Directory of Open Access Journals (Sweden)

    Ana Bernardo

    2017-09-01

    Full Text Available University program dropout is a problem that has important consequences not only for the student that leaves but also for the institution in which the withdrawal occurs. Therefore, higher education institutions must study the problem in greater depth to establish appropriate prevention measures in the future. However, most research papers currently focus primarily on the characteristics of students who leave university, rather than on those who choose to pursue alternative courses of study and therefore fail to take into account the different kinds of abandonment. The aim of this paper is to identify the different types of dropout to define their characteristics and propose some recommendations. Thus, an ex post facto study was carried out on a sample of 1,311 freshmen from a university in the north of Spain using data gathered using an ad-hoc designed questionnaire, applied by telephone or an online survey, and completed with data available in the university data warehouse. A descriptive analysis was performed to characterize the sample and identify five different groups, including 1. Students persisting in their initiated degree 2. Students who change of program (within the same university 3. Students transferring to a different university 4. Students enrolling in non-higher-education studies 5. Students that quit studying. Also, data mining techniques (decision trees were applied to classify the cases and generate predictive models to aid in the design of differentiated intervention strategies for each of the corresponding groups.

  9. Obesity and the Social Withdrawal Syndrome.

    Science.gov (United States)

    Rotenberg, Ken J; Bharathi, Carla; Davies, Helen; Finch, Tom

    2017-08-01

    The relation between obesity and Social Withdrawal Syndrome (SWS) was examined using the data gathered by Rotenberg, Bharathi, Davies, and Finch (2013). One hundred and 35 undergraduates (80 females; Mage=21years-10months) completed standardized scales that assessed the SWS (low emotional trust beliefs in close others, low disclosure to close others, and high loneliness). BMI was calculated from self-reported weight and height. As hypothesized, quadratic relations were found in which participants with BMI>30 (i.e., obese) demonstrated the SWS pattern of low emotional trust beliefs in close others, low disclosure to close others, and high loneliness. As further evidence, lower emotional trust in close others, lower disclosure to close others, and greater loneliness were found for obese participants (>30 BMI, n=27) than both normal weight (<25 BMI, n=67) and overweight participants (25 to 30 BMI, n=41). The findings confirmed the hypothesis that obesity was associated with the SWS. The findings suggested that the lack of trust in others by obese individuals contributes to their unwillingness to seek out help for health and psychosocial problems. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Freshmen Program Withdrawal: Types and Recommendations

    Science.gov (United States)

    Bernardo, Ana; Cervero, Antonio; Esteban, María; Tuero, Ellian; Casanova, Joana R.; Almeida, Leandro S.

    2017-01-01

    University program dropout is a problem that has important consequences not only for the student that leaves but also for the institution in which the withdrawal occurs. Therefore, higher education institutions must study the problem in greater depth to establish appropriate prevention measures in the future. However, most research papers currently focus primarily on the characteristics of students who leave university, rather than on those who choose to pursue alternative courses of study and therefore fail to take into account the different kinds of abandonment. The aim of this paper is to identify the different types of dropout to define their characteristics and propose some recommendations. Thus, an ex post facto study was carried out on a sample of 1,311 freshmen from a university in the north of Spain using data gathered using an ad-hoc designed questionnaire, applied by telephone or an online survey, and completed with data available in the university data warehouse. A descriptive analysis was performed to characterize the sample and identify five different groups, including 1. Students persisting in their initiated degree 2. Students who change of program (within the same university) 3. Students transferring to a different university 4. Students enrolling in non-higher-education studies 5. Students that quit studying. Also, data mining techniques (decision trees) were applied to classify the cases and generate predictive models to aid in the design of differentiated intervention strategies for each of the corresponding groups. PMID:28983263

  11. Strong Electroweak Symmetry Breaking

    CERN Document Server

    Grinstein, Benjamin

    2011-01-01

    Models of spontaneous breaking of electroweak symmetry by a strong interaction do not have fine tuning/hierarchy problem. They are conceptually elegant and use the only mechanism of spontaneous breaking of a gauge symmetry that is known to occur in nature. The simplest model, minimal technicolor with extended technicolor interactions, is appealing because one can calculate by scaling up from QCD. But it is ruled out on many counts: inappropriately low quark and lepton masses (or excessive FCNC), bad electroweak data fits, light scalar and vector states, etc. However, nature may not choose the minimal model and then we are stuck: except possibly through lattice simulations, we are unable to compute and test the models. In the LHC era it therefore makes sense to abandon specific models (of strong EW breaking) and concentrate on generic features that may indicate discovery. The Technicolor Straw Man is not a model but a parametrized search strategy inspired by a remarkable generic feature of walking technicolor,...

  12. TRACY transient experiment databook. 2) ramp withdrawal experiment

    International Nuclear Information System (INIS)

    Nakajima, Ken; Yamane, Yuichi; Ogawa, Kazuhiko; Aizawa, Eiju; Yanagisawa, Hiroshi; Miyoshi, Yoshinori

    2002-03-01

    This is a databook of TRACY ''ramp withdrawal'' experiments. TRACY is a reactor to perform supercritical experiments using low-enriched uranyl nitrate aqueous solution. The excess reactivity of TRACY is 3$ at maximum, and it is inserted by feeding the solution to a core tank or by withdrawing a control rod, which is called as the transient rod, from the core. In the ramp withdrawal experiment, the supercritical experiment is initiated by withdrawing the transient rod from the core in a constant speed using a motor drive system. The data in the present databook consist of datasheets and graphs. Experimental conditions and typical values of measured parameters are tabulated in the datasheet. In the graph, power and temperature profiles are plotted. Those data are useful for the investigation of criticality accidents with fissile solutions, and for validation of criticality accident analysis codes. (author)

  13. Prolonged social withdrawal disorder: a hikikomori case in Spain.

    Science.gov (United States)

    Ovejero, Santiago; Caro-Cañizares, Irene; de León-Martínez, Victoria; Baca-Garcia, Enrique

    2014-09-01

    The Japanese term hikikomori means literally 'to be confined'. Social withdrawal can be present in severe psychiatric disorders; however, in Japan, hikikomori is a defined nosologic entity. There have been only a few reported cases in occidental culture. We present a case report of a Spanish man with prolonged social withdrawal lasting for 4 years. This is a case of prolonged social withdrawal not bound to culture, as well as the second case of hikikomori reported in Spain. We propose prolonged social withdrawal disorder as a disorder not linked to culture, in contrast to hikikomori. Further documentation of this disorder is still needed to encompass all cases reported in Japan and around the world. © The Author(s) 2013.

  14. Ethical Analysis of Withdrawing Ventricular Assist Device Support

    OpenAIRE

    Mueller, Paul S.; Swetz, Keith M.; Freeman, Monica R.; Carter, Kari A.; Crowley, Mary Eliot; Severson, Cathy J. Anderson; Park, Soon J.; Sulmasy, Daniel P.

    2010-01-01

    OBJECTIVE: To describe a series of patients with heart failure supported with a ventricular assist device (VAD) who requested (or whose surrogates requested) withdrawal of VAD support and the legal and ethical aspects pertaining to these requests.

  15. 24 CFR 180.210 - Withdrawal or disqualification of ALJ.

    Science.gov (United States)

    2010-04-01

    ... EMPLOYMENT AND BUSINESS OPPORTUNITY CONSOLIDATED HUD HEARING PROCEDURES FOR CIVIL RIGHTS MATTERS Administrative Law Judge § 180.210 Withdrawal or disqualification of ALJ. (a) Disqualification. If an ALJ finds...

  16. Caffeine withdrawal symptoms and self-administration following caffeine deprivation.

    Science.gov (United States)

    Mitchell, S H; de Wit, H; Zacny, J P

    1995-08-01

    This study examined the effects of complete or partial caffeine deprivation on withdrawal symptomatology and self-administration of coffee in caffeine-dependent coffee drinkers. Nine habitual coffee drinkers abstained from dietary sources of caffeine for 33.5 h. Caffeine deprivation was manipulated by administering capsules containing 0%, 50%, or 100% of each subject's daily caffeine intake (complete, partial, and no deprivation conditions). Caffeine withdrawal symptomatology was measured using self-report questionnaires. Caffeine self-administration was measured using: i) the amount of coffee subjects earned on a series of concurrent random-ratio schedules that yielded coffee and money reinforcers; ii) the amount of earned coffee they consumed. Saliva samples revealed that subjects complied with the caffeine abstinence instructions. Caffeine withdrawal symptoms occurred reliably following complete caffeine deprivation, though not in the partial deprivation condition. Caffeine self-administration was not related to deprivation condition. We conclude that caffeine withdrawal symptomatology is not necessarily associated with increased caffeine consumption.

  17. Steroid withdrawal in renal transplant patients: the Irish experience.

    LENUS (Irish Health Repository)

    Phelan, P J

    2012-02-01

    BACKGROUND: Steroid therapy is associated with significant morbidity in renal transplant recipients. However, there is concern that steroid withdrawal will adversely affect outcome. METHODS: We report on 241 renal transplant recipients on different doses of corticosteroids at 3 months (zero, <\\/= 5 mg\\/day, > 5 mg\\/day). Parameters analysed included blood pressure, lipid profile, weight change, new onset diabetes after transplantation (NODAT), allograft survival and acute rejection. RESULTS: Elimination of corticosteroids had no impact on allograft survival at 1 year. There were no cases of NODAT in the steroid withdrawal group compared with over 7% in each of the steroid groups. There were no significant improvements in weight gain, blood pressure control or total cholesterol with withdrawal of steroids before 3 months. CONCLUSIONS: In renal transplant patients treated with tacrolimus and mycophenolate, early withdrawal of steroids does not appear to adversely affect allograft outcome at 1 year. It may result in less NODAT.

  18. Sedative-hypnotic drug withdrawal syndrome: recognition and treatment [digest].

    Science.gov (United States)

    Santos, Cynthia; Olmedo, Ruben E; Kim, Jeremy

    2017-03-22

    Sedative-hypnotic drugs include gamma-Aminobutyric acid (GABA)ergic agents such as benzodiazepines, barbiturates, gamma-Hydroxybutyric acid [GHB], gamma-Butyrolactone [GBL], baclofen, and ethanol. Chronic use of these substances can cause tolerance, and abrupt cessation or a reduction in the quantity of the drug can precipitate a life-threatening withdrawal syndrome. Benzodiazepines, phenobarbital, propofol, and other GABA agonists or analogues can effectively control symptoms of withdrawal from GABAergic agents. Managing withdrawal symptoms requires a patient-specific approach that takes into account the physiologic pathways of the particular drugs used as well as the patient's age and comorbidities. Adjunctive therapies include alpha agonists, beta blockers, anticonvulsants, and antipsychotics. Newer pharmacological therapies offer promise in managing withdrawal symptoms. [Points & Pearls is a digest of Emergency Medicine Practice].

  19. State National Pollutant Discharge Elimination System (NPDES) Program Withdrawal Petitions

    Data.gov (United States)

    U.S. Environmental Protection Agency — Search for pending and resolved NPDES withdrawal petitions by state, region, date, or keyword. "Pending" means EPA has received the petition and is working with the...

  20. Induction of synaptic long-term potentiation after opioid withdrawal.

    Science.gov (United States)

    Drdla, Ruth; Gassner, Matthias; Gingl, Ewald; Sandkühler, Jürgen

    2009-07-10

    mu-Opioid receptor (MOR) agonists represent the gold standard for the treatment of severe pain but may paradoxically also enhance pain sensitivity, that is, lead to opioid-induced hyperalgesia (OIH). We show that abrupt withdrawal from MOR agonists induces long-term potentiation (LTP) at the first synapse in pain pathways. Induction of opioid withdrawal LTP requires postsynaptic activation of heterotrimeric guanine nucleotide-binding proteins and N-methyl-d-aspartate receptors and a rise of postsynaptic calcium concentrations. In contrast, the acute depression by opioids is induced presynaptically at these synapses. Withdrawal LTP can be prevented by tapered withdrawal and shares pharmacology and signal transduction pathways with OIH. These findings provide a previously unrecognized target to selectively combat pro-nociceptive effects of opioids without compromising opioid analgesia.

  1. Strong-coupling theory of superconductivity

    International Nuclear Information System (INIS)

    Rainer, D.; Sauls, J.A.

    1995-01-01

    The electronic properties of correlated metals with a strong electron-phonon coupling may be understood in terms of a combination of Landau''s Fermi liquid theory and the strong-coupling theory of Migdal and Eliashberg. In these lecture notes we discuss the microscopic foundations of this phenomenological Fermi-liquid model of correlated, strong-coupling metals. We formulate the basic equations of the model, which are quasiclassical transport equations that describe both equilibrium and non-equilibrium phenomena for the normal and superconducting states of a metal. Our emphasis is on superconductors close to equilibrium, for which we derive the general linear response theory. As an application we calculate the dynamical conductivity of strong-coupling superconductors. (author)

  2. Consequences of a withdrawal from the use of nuclear energy

    International Nuclear Information System (INIS)

    Wagner, H.J.; Bundschuh, V.; Duering, K.; Martinsen, D.; Riemer, H.; Walbeck, M.

    1986-01-01

    First the consequences of an immediate withdrawal are considered, i.e. a replacement of electricity generation capacity can not be built up in time. Then assumptions and results for a withdrawal in stages are presented. This means, that a replacement of nuclear generation capacity is possible. The applied energy model allows statements about the future structure of energy supply, the mass balances, the costs, and the SO 2 , NO x and CO 2 emissions from increased coal combustion. (orig./HP) [de

  3. Strong spin-photon coupling in silicon

    Science.gov (United States)

    Samkharadze, N.; Zheng, G.; Kalhor, N.; Brousse, D.; Sammak, A.; Mendes, U. C.; Blais, A.; Scappucci, G.; Vandersypen, L. M. K.

    2018-03-01

    Long coherence times of single spins in silicon quantum dots make these systems highly attractive for quantum computation, but how to scale up spin qubit systems remains an open question. As a first step to address this issue, we demonstrate the strong coupling of a single electron spin and a single microwave photon. The electron spin is trapped in a silicon double quantum dot, and the microwave photon is stored in an on-chip high-impedance superconducting resonator. The electric field component of the cavity photon couples directly to the charge dipole of the electron in the double dot, and indirectly to the electron spin, through a strong local magnetic field gradient from a nearby micromagnet. Our results provide a route to realizing large networks of quantum dot–based spin qubit registers.

  4. Strongly intensive quantities

    International Nuclear Information System (INIS)

    Gorenstein, M. I.; Gazdzicki, M.

    2011-01-01

    Analysis of fluctuations of hadron production properties in collisions of relativistic particles profits from use of measurable intensive quantities which are independent of system size variations. The first family of such quantities was proposed in 1992; another is introduced in this paper. Furthermore we present a proof of independence of volume fluctuations for quantities from both families within the framework of the grand canonical ensemble. These quantities are referred to as strongly intensive ones. Influence of conservation laws and resonance decays is also discussed.

  5. Strong-coupling approximations

    International Nuclear Information System (INIS)

    Abbott, R.B.

    1984-03-01

    Standard path-integral techniques such as instanton calculations give good answers for weak-coupling problems, but become unreliable for strong-coupling. Here we consider a method of replacing the original potential by a suitably chosen harmonic oscillator potential. Physically this is motivated by the fact that potential barriers below the level of the ground-state energy of a quantum-mechanical system have little effect. Numerically, results are good, both for quantum-mechanical problems and for massive phi 4 field theory in 1 + 1 dimensions. 9 references, 6 figures

  6. Cyclotron resonance cooling by strong laser field

    International Nuclear Information System (INIS)

    Tagcuhi, Toshihiro; Mima, Kunioka

    1995-01-01

    Reduction of energy spread of electron beam is very important to increase a total output radiation power in free electron lasers. Although several cooling systems of particle beams such as a stochastic cooling are successfully operated in the accelerator physics, these cooling mechanisms are very slow and they are only applicable to high energy charged particle beams of ring accelerators. We propose here a new concept of laser cooling system by means of cyclotron resonance. Electrons being in cyclotron motion under a strong magnetic field can resonate with circular polarized electromagnetic field, and the resonance take place selectively depending on the velocity of the electrons. If cyclotron frequency of electrons is equal to the frequency of the electromagnetic field, they absorb the electromagnetic field energy strongly, but the other electrons remain unchanged. The absorbed energy will be converted to transverse kinetic energy, and the energy will be dumped into the radiation energy through bremastrahlung. To build a cooling system, we must use two laser beams, where one of them is counter-propagating and the other is co-propagating with electron beam. When the frequency of the counter-propagating laser is tuned with the cyclotron frequency of fast electrons and the co-propagating laser is tuned with the cyclotron frequency of slow electrons, the energy of two groups will approach and the cooling will be achieved. We solve relativistic motions of electrons with relativistic radiation dumping force, and estimate the cooling rate of this mechanism. We will report optimum parameters for the electron beam cooling system for free electron lasers

  7. Narp regulates long-term aversive effects of morphine withdrawal

    Science.gov (United States)

    Reti, Irving M.; Crombag, Hans S.; Takamiya, Kogo; Sutton, Jeffrey M.; Guo, Ning; Dinenna, Megan L.; Huganir, Richard L.; Holland, Peter C.; Baraban, Jay M.

    2008-01-01

    Although long-lasting effects of drug withdrawal are thought to play a key role in motivating continued drug use, the mechanisms mediating this type of drug-induced plasticity are unclear. As Narp is an immediate early gene product that is secreted at synaptic sites and binds to AMPA receptors, it has been implicated in mediating enduring forms of synaptic plasticity. In previous studies, we found that Narp is selectively induced by morphine withdrawal in the extended amygdala, a group of limbic nuclei that mediate aversive behavioral responses. Accordingly, in this study, we evaluated whether long-term aversive effects of morphine withdrawal are altered in Narp KO mice. We found that acute physical signs of morphine withdrawal are unaffected by Narp deletion. However, Narp KO mice acquire and sustain more aversive responses to the environment conditioned with morphine withdrawal than WT controls. Paradoxically, Narp KO mice undergo accelerated extinction of this heightened aversive response. Taken together, these studies suggest that Narp modulates both acquisition and extinction of aversive responses to morphine withdrawal and, therefore, may regulate plasticity processes underlying drug addiction. PMID:18729628

  8. Acupuncture for alcohol withdrawal: a randomized controlled trial.

    Science.gov (United States)

    Trümpler, François; Oez, Suzan; Stähli, Peter; Brenner, Hans Dieter; Jüni, Peter

    2003-01-01

    Previous trials on acupuncture in alcohol addiction were in outpatients and focused on relapse prevention. Rates of dropout were high and interpretation of results difficult. We compared auricular laser and needle acupuncture with sham laser stimulation in reducing the duration of alcohol withdrawal. Inpatients undergoing alcohol withdrawal were randomly allocated to laser acupuncture (n = 17), needle acupuncture (n = 15) or sham laser stimulation (n = 16). Attempts were made to blind patients, therapists and outcome assessors, but this was not feasible for needle acupuncture. The duration of withdrawal symptoms (as assessed using a nurse-rated scale) was the primary outcome; the duration of sedative prescription was the secondary outcome. Patients randomized to laser and sham laser had identical withdrawal symptom durations (median 4 days). Patients randomized to needle stimulation had a shorter duration of withdrawal symptoms (median 3 days; P = 0.019 versus sham intervention), and tended to have a shorter duration of sedative use, but these differences diminished after adjustment for baseline differences. The data from this pilot trial do not suggest a relevant benefit of auricular laser acupuncture for alcohol withdrawal. A larger trial including adequate sham interventions is needed, however, to reliably determine the effectiveness of any type of auricular acupuncture in this condition.

  9. A case of rhabdomyolysis associated with severe opioid withdrawal.

    Science.gov (United States)

    Gangahar, Deepali

    2015-08-01

    While the risk of opioid overdose is widely accepted, the dangers of opioid withdrawal are far less clearly defined. The purpose of this publication is to provide evidence against the erroneous clinical dictum that opioid withdrawal is never life-threatening. This case report (N = 1) illustrates an unfortunate, common scenario of a man abusing prescription opioids and heroin. His attempt at self-detoxification with buprenorphine-naloxone resulted in life-threatening opioid withdrawal. A detailed account of each day of his withdrawal period was documented by patient and family report and review of all medical records. The patient was contacted three months after hospitalization to verify information and determine progress in treatment and abstinence from drugs and alcohol. A review of the literature was completed on severe cases of precipitated and spontaneous opioid withdrawal followed by a discussion of the significance as it relates to this case. Given the widespread use of prescription opioids and opioid maintenance treatment, physicians should be aware of the complications of acute opioid withdrawal and should be equipped to treat these complications. © American Academy of Addiction Psychiatry.

  10. Measurement of nicotine withdrawal symptoms: linguistic validation of the Wisconsin Smoking Withdrawal Scale (WSWS in Malay

    Directory of Open Access Journals (Sweden)

    Shafie Asrul A

    2010-05-01

    Full Text Available Abstract Background The purpose of the linguistic validation of the Wisconsin Smoking Withdrawal Scale (WSWS was to produce a translated version in Malay language which was "conceptually equivalent" to the original U.S. English version for use in clinical practice and research. Methods A seven-member translation committee conducted the translation process using the following methodology: production of two independent forward translations; comparison and reconciliation of the translations; backward translation of the first reconciled version; comparison of the original WSWS and the backward version leading to the production of the second reconciled version; pilot testing and review of the translation, and finalization. Results Linguistic and conceptual issues arose during the process of translating the instrument, particularly pertaining to the title, instructions, and some of the items of the scale. In addition, the researchers had to find culturally acceptable equivalents for some terms and idiomatic phrases. Notable among these include expressions such as "irritability", "feeling upbeat", and "nibbling on snacks", which had to be replaced by culturally acceptable expressions. During cognitive debriefing and clinician's review processes, the Malay translated version of WSWS was found to be easily comprehensible, clear, and appropriate for the smoking withdrawal symptoms intended to be measured. Conclusions We applied a rigorous translation method to ensure conceptual equivalence and acceptability of WSWS in Malay prior to its utilization in research and clinical practice. However, to complete the cultural adaptation process, future psychometric validation is planned to be conducted among Malay speakers.

  11. Strong Coupling Holography

    CERN Document Server

    Dvali, Gia

    2009-01-01

    We show that whenever a 4-dimensional theory with N particle species emerges as a consistent low energy description of a 3-brane embedded in an asymptotically-flat (4+d)-dimensional space, the holographic scale of high-dimensional gravity sets the strong coupling scale of the 4D theory. This connection persists in the limit in which gravity can be consistently decoupled. We demonstrate this effect for orbifold planes, as well as for the solitonic branes and string theoretic D-branes. In all cases the emergence of a 4D strong coupling scale from bulk holography is a persistent phenomenon. The effect turns out to be insensitive even to such extreme deformations of the brane action that seemingly shield 4D theory from the bulk gravity effects. A well understood example of such deformation is given by large 4D Einstein term in the 3-brane action, which is known to suppress the strength of 5D gravity at short distances and change the 5D Newton's law into the four-dimensional one. Nevertheless, we observe that the ...

  12. Withdrawal of immunomodulators after co-treatment does not reduce trough level of infliximab in patients with Crohn's disease.

    Science.gov (United States)

    Drobne, David; Bossuyt, Peter; Breynaert, Christine; Cattaert, Tom; Vande Casteele, Niels; Compernolle, Griet; Jürgens, Matthias; Ferrante, Marc; Ballet, Vera; Wollants, Willem-Jan; Cleynen, Isabelle; Van Steen, Kristel; Gils, Ann; Rutgeerts, Paul; Vermeire, Severine; Van Assche, Gert

    2015-03-01

    The addition of immunomodulators increases the efficacy of maintenance therapy with infliximab for up to 1 year in patients with Crohn's disease who have not been previously treated with immunomodulators. However, there are questions about the effect of withdrawing immunomodulator therapy from these patients. We studied the effects of treatment with infliximab and immunomodulators (co-treatment) and then immunomodulator withdrawal on long-term outcomes of patients, as well as trough levels of infliximab and formation of anti-infliximab antibodies (ATI). In a retrospective study with the median follow-up period of 34 months (interquartile range, 19-58 months), we analyzed data from 223 patients treated for Crohn's disease between May 1999 and December 2010 at the University Hospitals, Leuven, Belgium (65 received infliximab monotherapy, 158 received infliximab and an immunomodulator). Trough levels of infliximab and levels of ATI were measured in blood samples collected from 117 patients throughout co-treatment, as well as the time of immunomodulator withdrawal and after withdrawal. Patients receiving co-treatment had higher trough levels of infliximab (adjusted mean increase, 1.44-fold) than those receiving infliximab monotherapy (95% confidence interval [CI], 1.07-1.92; P = .02). A smaller percentage of patients receiving co-treatment developed ATI (35 of 158, 22%) than those receiving infliximab monotherapy (25 of 65, 38%; P = .01). Among co-treated patients, levels of infliximab remained stable after immunomodulators were withdrawn (before: 3.2 μg/mL; 95% CI, 1.6-5.8 μg/mL and after: 3.7 μg/mL; 95% CI, 1.3-6.3 μg/mL; P = .70). After withdrawal of immunomodulators, 45 of 117 patients (38%) required increasing doses of infliximab, and 21 of 117 (18%) discontinued infliximab. At the time of immunomodulator withdrawal, trough levels of infliximab and C-reactive protein were most strongly associated with response to infliximab thereafter. In a retrospective

  13. Group Theory and Crystal Field Theory: A Simple and Rigorous Derivation of the Spectroscopic Terms Generated by the t[subscript 2g][superscript 2] Electronic Configuration in a Strong Octahedral Field

    Science.gov (United States)

    Morpurgo, Simone

    2007-01-01

    The principles of symmetry and group theory are applied to the zero-order wavefunctions associated with the strong-field t[subscript 2g][superscript 2] configuration and their symmetry-adapted linear combinations (SALC) associated with the generated energy terms are derived. This approach will enable students to better understand the use of…

  14. LIGO: The strong belief

    CERN Multimedia

    Antonella Del Rosso

    2016-01-01

    Twenty years of designing, building and testing a number of innovative technologies, with the strong belief that the endeavour would lead to a historic breakthrough. The Bulletin publishes an abstract of the Courier’s interview with Barry Barish, one of the founding fathers of LIGO.   The plots show the signals of gravitational waves detected by the twin LIGO observatories at Livingston, Louisiana, and Hanford, Washington. (Image: Caltech/MIT/LIGO Lab) On 11 February, the Laser Interferometer Gravitational-Wave Observatory (LIGO) and Virgo collaborations published a historic paper in which they showed a gravitational signal emitted by the merger of two black holes. These results come after 20 years of hard work by a large collaboration of scientists operating the two LIGO observatories in the US. Barry Barish, Linde Professor of Physics, Emeritus at the California Institute of Technology and former Director of the Global Design Effort for the Internat...

  15. Strongly interacting Higgs bosons

    International Nuclear Information System (INIS)

    Appelquist, T.; Bernard, C.

    1980-01-01

    The sensitivity of present-energy weak interactions to a strongly interacting heavy-Higgs-boson sector is discussed. The gauged nonlinear sigma model, which is the limit of the linear model as the Higgs-boson mass goes to infinity, is used to organize and catalogue all possible heavy-Higgs-boson effects. As long as the SU(2)/sub L/ x SU(2)/sub R/ symmetry of the Higgs sector is preserved, these effects are found to be small, of the order of the square of the gauge coupling times logarithms (but not powers) of the Higgs-boson mass divided by the W mass. We work in the context of a simplified model with gauge group SU(2)/sub L/; the extension to SU(2)/sub L/ x U(1) is briefly discussed

  16. Psychological distress, social withdrawal, and coping following receipt of an abnormal mammogram among different ethnicities: a mediation model.

    Science.gov (United States)

    Molina, Yamile; Beresford, Shirley A A; Espinoza, Noah; Thompson, Beti

    2014-09-01

    To explore ethnic differences in psychological distress and social withdrawal after receiving an abnormal mammogram result and to assess if coping strategies mediate ethnic differences. Descriptive correlational. Two urban mobile mammography units and a rural community hospital in the state of Washington. 41 Latina and 41 non-Latina Caucasian (NLC) women who had received an abnormal mammogram result. Women completed standard sociodemographic questions, Impact of Event Scale-Revised, the social dimension of the Psychological Consequences Questionnaire, and the Brief COPE. Ethnicity, psychological distress, social withdrawal, and coping. Latinas experienced greater psychological distress and social withdrawal compared to NLC counterparts. Denial as a coping strategy mediated ethnic differences in psychological distress. Religious coping mediated ethnic differences in social withdrawal. Larger population-based studies are necessary to understand how ethnic differences in coping strategies can influence psychological outcomes. This is an important finding that warrants additional study among women who are and are not diagnosed with breast cancer following an abnormal mammogram. Nurses may be able to work with Latina patients to diminish denial coping and consequent distress. Nurses may be particularly effective, given cultural values concerning strong interpersonal relationships and respect for authority figures.

  17. Multigap superconductivity and strong electron-boson coupling in Fe-based superconductors: a point-contact Andreev-reflection study of Ba(Fe(1-x)Co(x))2As2 single crystals.

    Science.gov (United States)

    Tortello, M; Daghero, D; Ummarino, G A; Stepanov, V A; Jiang, J; Weiss, J D; Hellstrom, E E; Gonnelli, R S

    2010-12-03

    Directional point-contact Andreev-reflection measurements in Ba(Fe(1-x)Co(x))2As2 single crystals (T(c) = 24.5 K) indicate the presence of two superconducting gaps with no line nodes on the Fermi surface. The point-contact Andreev-reflection spectra also feature additional structures related to the electron-boson interaction, from which the characteristic boson energy Ω(b)(T) is obtained, very similar to the spin-resonance energy observed in neutron scattering experiments. Both the gaps and the additional structures can be reproduced within a three-band s ± Eliashberg model by using an electron-boson spectral function peaked at Ω(0) = 12 meV ≃ Ω(b)(0).

  18. Determinants of early withdrawal and of early withdrawal by reason of disability from the Irish labour force in the third age

    OpenAIRE

    Lawless, Martin

    2015-01-01

    III – Abstract: Determinants of early withdrawal and early withdrawal by reason of disability from the Irish labour force in the Third Age.Background. This study examines the relationship between early withdrawal and early withdrawal through disability from the Irish labour force in the Third Age. The relationship between unemployment or early retirement and ill health has been determined by a number of studies and, while unemployment through ill health or occupational disability may lead to ...

  19. To Withdraw Or Not To Withdraw? Evaluation of the Mandatory Right of Withdrawal in Consumer Distance Selling Contracts Taking Into Account Its Behavioural Effects on Consumers

    NARCIS (Netherlands)

    Luzak, J.A.

    2014-01-01

    The right of withdrawal was introduced to European consumer law as an exception to the general contractual principle of pacta sunt servanda. It has recently been upheld in the Consumer Rights Directive as a mandatory right for consumers concluding distance selling contracts. Among various

  20. Strong field control of predissociation dynamics.

    Science.gov (United States)

    Corrales, María E; Balerdi, Garikoitz; Loriot, Vincent; de Nalda, Rebeca; Bañares, Luis

    2013-01-01

    Strong field control scenarios are investigated in the CH3I predissociation dynamics at the origin of the second absorption B-band, in which state-selective electronic predissociation occurs through the crossing with a valence dissociative state. Dynamic Stark control (DSC) and pump-dump strategies are shown capable of altering both the predissociation lifetime and the product branching ratio.

  1. Strong-interaction nonuniversality

    International Nuclear Information System (INIS)

    Volkas, R.R.; Foot, R.; He, X.; Joshi, G.C.

    1989-01-01

    The universal QCD color theory is extended to an SU(3) 1 direct product SU(3) 2 direct product SU(3) 3 gauge theory, where quarks of the ith generation transform as triplets under SU(3)/sub i/ and singlets under the other two factors. The usual color group is then identified with the diagonal subgroup, which remains exact after symmetry breaking. The gauge bosons associated with the 16 broken generators then form two massive octets under ordinary color. The interactions between quarks and these heavy gluonlike particles are explicitly nonuniversal and thus an exploration of their physical implications allows us to shed light on the fundamental issue of strong-interaction universality. Nonuniversality and weak flavor mixing are shown to generate heavy-gluon-induced flavor-changing neutral currents. The phenomenology of these processes is studied, as they provide the major experimental constraint on the extended theory. Three symmetry-breaking scenarios are presented. The first has color breaking occurring at the weak scale, while the second and third divorce the two scales. The third model has the interesting feature of radiatively induced off-diagonal Kobayashi-Maskawa matrix elements

  2. Stirring Strongly Coupled Plasma

    CERN Document Server

    Fadafan, Kazem Bitaghsir; Rajagopal, Krishna; Wiedemann, Urs Achim

    2009-01-01

    We determine the energy it takes to move a test quark along a circle of radius L with angular frequency w through the strongly coupled plasma of N=4 supersymmetric Yang-Mills (SYM) theory. We find that for most values of L and w the energy deposited by stirring the plasma in this way is governed either by the drag force acting on a test quark moving through the plasma in a straight line with speed v=Lw or by the energy radiated by a quark in circular motion in the absence of any plasma, whichever is larger. There is a continuous crossover from the drag-dominated regime to the radiation-dominated regime. In the crossover regime we find evidence for significant destructive interference between energy loss due to drag and that due to radiation as if in vacuum. The rotating quark thus serves as a model system in which the relative strength of, and interplay between, two different mechanisms of parton energy loss is accessible via a controlled classical gravity calculation. We close by speculating on the implicati...

  3. Transport phenomena in strongly correlated Fermi liquids

    International Nuclear Information System (INIS)

    Kontani, Hiroshi

    2013-01-01

    Comprehensive overview. Written by an expert of this topic. Provides the reader with current developments in the field. In conventional metals, various transport coefficients are scaled according to the quasiparticle relaxation time, τ, which implies that the relaxation time approximation (RTA) holds well. However, such a simple scaling does not hold in many strongly correlated electron systems, reflecting their unique electronic states. The most famous example would be cuprate high-Tc superconductors (HTSCs), where almost all the transport coefficients exhibit a significant deviation from the RTA results. To better understand the origin of this discrepancy, we develop a method for calculating various transport coefficients beyond the RTA by employing field theoretical techniques. Near the magnetic quantum critical point, the current vertex correction (CVC), which describes the electron-electron scattering beyond the relaxation time approximation, gives rise to various anomalous transport phenomena. We explain anomalous transport phenomena in cuprate HTSCs and other metals near their magnetic or orbital quantum critical point using a uniform approach. We also discuss spin related transport phenomena in strongly correlated systems. In many d- and f-electron systems, the spin current induced by the spin Hall effect is considerably greater because of the orbital degrees of freedom. This fact attracts much attention due to its potential application in spintronics. We discuss various novel charge, spin and heat transport phenomena in strongly correlated metals.

  4. Electromagnetic processes in strong crystalline fields

    CERN Multimedia

    2007-01-01

    We propose a number of new investigations on aspects of radiation from high energy electron and positron beams (10-300 GeV) in single crystals and amorphous targets. The common heading is radiation emission by electrons and positrons in strong electromagnetic fields, but as the setup is quite versatile, other related phenomena in radiation emission can be studied as well. The intent is to clarify the role of a number of important aspects of radiation in strong fields as e.g. observed in crystals. We propose to measure trident 'Klein-like' production in strong crystalline fields, 'crystalline undulator' radiation, 'sandwich' target phenomena, LPM suppression of pair production as well as axial and planar effects in contributions of spin to the radiation.

  5. Impacts of crop insurance on water withdrawals for irrigation

    Science.gov (United States)

    Deryugina, Tatyana; Konar, Megan

    2017-12-01

    Agricultural production remains particularly vulnerable to weather fluctuations and extreme events, such as droughts, floods, and heat waves. Crop insurance is a risk management tool developed to mitigate some of this weather risk and protect farmer income in times of poor production. However, crop insurance may have unintended consequences for water resources sustainability, as the vast majority of freshwater withdrawals go to agriculture. The causal impact of crop insurance on water use in agriculture remains poorly understood. Here, we determine the empirical relationship between crop insurance and irrigation water withdrawals in the United States. Importantly, we use an instrumental variables approach to establish causality. Our methodology exploits a major policy change in the crop insurance system - the 1994 Federal Crop Insurance Reform Act - which imposed crop insurance requirements on farmers. We find that a 1% increase in insured crop acreage leads to a 0.223% increase in irrigation withdrawals, with most coming from groundwater aquifers. We identify farmers growing more groundwater-fed cotton as an important mechanism contributing to increased withdrawals. A 1% increase in insured crop acreage leads to a 0.624% increase in cotton acreage, or 95,602 acres. These results demonstrate that crop insurance causally leads to more irrigation withdrawals. More broadly, this work underscores the importance of determining causality in the water-food nexus as we endeavor to achieve global food security and water resources sustainability.

  6. The acute tobacco withdrawal syndrome among black smokers.

    Science.gov (United States)

    Robinson, Cendrine D; Pickworth, Wallace B; Heishman, Stephen J; Waters, Andrew J

    2014-03-01

    Black smokers have greater difficulty quitting tobacco than White smokers, but the mechanisms underlying between-race differences in smoking cessation are not clear. One possibility is that Black smokers experience greater acute withdrawal than Whites. We investigated whether Black (n = 104) and White smokers (n = 99) differed in abstinence-induced changes in self-report, physiological, and cognitive performance measures. Smokers not wishing to quit completed two counterbalanced experimental sessions. Before one session, they abstained from smoking for at least 12 hr. They smoked normally before the other session. Black smokers reported smaller abstinence-induced changes on a number of subjective measures including the total score of the 10-item Questionnaire for Smoking Urges (QSU) and the total score of the Wisconsin Smoking Withdrawal Scale (WSWS). However, on most subjective measures, and on all objective measures, there were no between-race differences in abstinence-induced change scores. Moreover, Black participants did not report lower QSU and WSWS ratings at the abstinent session, but they did experience significantly higher QSU and WSWS ratings at the nonabstinent session. Abstinence-induced changes in subjective, physiological, and cognitive measures in White smokers were similar for smokers of nonflavored and menthol-flavored cigarettes. There was no evidence that Black smokers experienced greater acute tobacco withdrawal than Whites. To the contrary, Black participants experienced smaller abstinence-induced changes in self-reported craving and withdrawal on some measures. Racial differences in smoking cessation are unlikely to be explained by acute withdrawal.

  7. Ethical Analysis of Withdrawing Total Artificial Heart Support.

    Science.gov (United States)

    DeMartino, Erin S; Wordingham, Sara E; Stulak, John M; Boilson, Barry A; Fuechtmann, Kayla R; Singh, Nausheen; Sulmasy, Daniel P; Pajaro, Octavio E; Mueller, Paul S

    2017-05-01

    To describe the characteristics of patients who undergo withdrawal of total artificial heart support and to explore the ethical aspects of withdrawing this life-sustaining treatment. We retrospectively reviewed the medical records of all adult recipients of a total artificial heart at Mayo Clinic from the program's inception in 2007 through June 30, 2015. Management of other life-sustaining therapies, approach to end-of-life decision making, engagement of ethics and palliative care consultation, and causes of death were analyzed. Of 47 total artificial heart recipients, 14 patients or their surrogates (30%) requested withdrawal of total artificial heart support. No request was denied by treatment teams. All 14 patients were supported with at least 1 other life-sustaining therapy. Only 1 patient was able to participate in decision making. It is widely held to be ethically permissible to withdraw a life-sustaining treatment when the treatment no longer meets the patient's health care-related goals (ie, the burdens outweigh the benefits). These data suggest that some patients, surrogates, physicians, and other care providers believe that this principle extends to the withdrawal of total artificial heart support. Copyright © 2017 Mayo Foundation for Medical Education and Research. Published by Elsevier Inc. All rights reserved.

  8. Opioid withdrawal syndrome: emerging concepts and novel therapeutic targets.

    Science.gov (United States)

    Rehni, Ashish K; Jaggi, Amteshwar S; Singh, Nirmal

    2013-02-01

    Opioid withdrawal syndrome is a debilitating manifestation of opioid dependence and responds poorly to the available clinical therapies. Studies from various in vivo and in vitro animal models of opioid withdrawal syndrome have led to understanding of its pathobiology which includes complex interrelated pathways leading to adenylyl cyclase superactivation based central excitation. Advancements in the elucidation of opioid withdrawal syndrome mechanisms have revealed a number of key targets that have been hypothesized to modulate clinical status. The present review discusses the neurobiology of opioid withdrawal syndrome and its therapeutic target recptors like calcitonin gene related peptide receptors (CGRP), N-methyl-D-aspartate (NMDA) receptors, gamma aminobutyric acid receptors (GABA), G-proteingated inwardly rectifying potassium (GIRK) channels and calcium channels. The present review further details the potential role of second messengers like calcium (Ca2+) / calmodulin-dependent protein kinase (CaMKII), nitric oxide synthase, cytokines, arachidonic acid metabolites, corticotropin releasing factor, fos and src kinases in causing opioid withdrawal syndrome. The exploitation of these targets may provide effective therapeutic agents for the management of opioid dependence-induced abstinence syndrome.

  9. Gut microbiota modulates alcohol withdrawal-induced anxiety in mice.

    Science.gov (United States)

    Xiao, Hui-Wen; Ge, Chang; Feng, Guo-Xing; Li, Yuan; Luo, Dan; Dong, Jia-Li; Li, Hang; Wang, Haichao; Cui, Ming; Fan, Sai-Jun

    2018-05-01

    Excessive alcohol consumption remains a major public health problem that affects millions of people worldwide. Accumulative experimental evidence has suggested an important involvement of gut microbiota in the modulation of host's immunological and neurological functions. However, it is previously unknown whether enteric microbiota is implicated in the formation of alcohol withdrawal-induced anxiety. Using a murine model of chronic alcoholism and withdrawal, we examined the impact of alcohol consumption on the possible alterations of gut microbiota as well as alcohol withdrawal-induced anxiety and behavior changes. The 16S rRNA sequencing revealed that alcohol consumption did not alter the abundance of bacteria, but markedly changed the composition of gut microbiota. Moreover, the transplantation of enteric microbes from alcohol-fed mice to normal healthy controls remarkably shaped the composition of gut bacteria, and elicited behavioral signs of alcohol withdrawal-induced anxiety. Using quantitative real-time polymerase chain reaction, we further confirmed that the expression of genes implicated in alcohol addiction, BDNF, CRHR1 and OPRM1, was also altered by transplantation of gut microbes from alcohol-exposed donors. Collectively, our findings suggested a possibility that the alterations of gut microbiota composition might contribute to the development of alcohol withdrawal-induced anxiety, and reveal potentially new etiologies for treating alcohol addiction. Copyright © 2018 The Author(s). Published by Elsevier B.V. All rights reserved.

  10. Electrophoresis in strong electric fields.

    Science.gov (United States)

    Barany, Sandor

    2009-01-01

    Two kinds of non-linear electrophoresis (ef) that can be detected in strong electric fields (several hundred V/cm) are considered. The first ("classical" non-linear ef) is due to the interaction of the outer field with field-induced ionic charges in the electric double layer (EDL) under conditions, when field-induced variations of electrolyte concentration remain to be small comparatively to its equilibrium value. According to the Shilov theory, the non-linear component of the electrophoretic velocity for dielectric particles is proportional to the cubic power of the applied field strength (cubic electrophoresis) and to the second power of the particles radius; it is independent of the zeta-potential but is determined by the surface conductivity of particles. The second one, the so-called "superfast electrophoresis" is connected with the interaction of a strong outer field with a secondary diffuse layer of counterions (space charge) that is induced outside the primary (classical) diffuse EDL by the external field itself because of concentration polarization. The Dukhin-Mishchuk theory of "superfast electrophoresis" predicts quadratic dependence of the electrophoretic velocity of unipolar (ionically or electronically) conducting particles on the external field gradient and linear dependence on the particle's size in strong electric fields. These are in sharp contrast to the laws of classical electrophoresis (no dependence of V(ef) on the particle's size and linear dependence on the electric field gradient). A new method to measure the ef velocity of particles in strong electric fields is developed that is based on separation of the effects of sedimentation and electrophoresis using videoimaging and a new flowcell and use of short electric pulses. To test the "classical" non-linear electrophoresis, we have measured the ef velocity of non-conducting polystyrene, aluminium-oxide and (semiconductor) graphite particles as well as Saccharomice cerevisiae yeast cells as a

  11. Impact of Water Withdrawals from Groundwater and Surface Water on Continental Water Storage Variations

    Science.gov (United States)

    Doell, Petra; Hoffmann-Dobrev, Heike; Portmann, Felix T.; Siebert, Stefan; Eicker, Annette; Rodell, Matthew; Strassberg, Gil

    2011-01-01

    Humans have strongly impacted the global water cycle, not only water flows but also water storage. We have performed a first global-scale analysis of the impact of water withdrawals on water storage variations, using the global water resources and use model WaterGAP. This required estimation of fractions of total water withdrawals from groundwater, considering five water use sectors. According to our assessment, the source of 35% of the water withdrawn worldwide (4300 cubic km/yr during 1998-2002) is groundwater. Groundwater contributes 42%, 36% and 27% of water used for irrigation, households and manufacturing, respectively, while we assume that only surface water is used for livestock and for cooling of thermal power plants. Consumptive water use was 1400 cubic km/yr during 1998-2002. It is the sum of the net abstraction of 250 cubic km/yr of groundwater (taking into account evapotranspiration and return flows of withdrawn surface water and groundwater) and the net abstraction of 1150 km3/yr of surface water. Computed net abstractions indicate, for the first time at the global scale, where and when human water withdrawals decrease or increase groundwater or surface water storage. In regions with extensive surface water irrigation, such as Southern China, net abstractions from groundwater are negative, i.e. groundwater is recharged by irrigation. The opposite is true for areas dominated by groundwater irrigation, such as in the High Plains aquifer of the central USA, where net abstraction of surface water is negative because return flow of withdrawn groundwater recharges the surface water compartments. In intensively irrigated areas, the amplitude of seasonal total water storage variations is generally increased due to human water use; however, in some areas, it is decreased. For the High Plains aquifer and the whole Mississippi basin, modeled groundwater and total water storage variations were compared with estimates of groundwater storage variations based on

  12. Drug withdrawal symptoms in children after continuous infusions of fentanyl.

    Science.gov (United States)

    French, J P; Nocera, M

    1994-04-01

    The purpose of this research was to determine the extent to which critically ill infants exhibited signs and symptoms of narcotic withdrawal after receiving continuous infusions of fentanyl. The convenience sample consisted of 12 pediatric intensive care unit (PICU) patients under 25 months of age who received fentanyl infusions for at least 24 hours. Drug withdrawal symptoms were monitored using the Neonatal Abstinence Score Tool (NAST), which assigns a score to each behavior indicative of withdrawal. A score of 8 or greater indicates Neonatal Abstinence Syndrome (NAS). Scoring began 4 hours after discontinuation of fentanyl and was conducted once per hour for 8 hours. Six subjects had a NAST score exceeding 8; these infants frequently exhibited tremors with or without stimulation, increased muscle tone, insomnia, and increased respiratory rate and effort. There were significant correlations between fentanyl dosage and NAST score (r = .76, p observation protocol and a possible weaning regimen after fentanyl is discontinued.

  13. Emplotting Hikikomori: Japanese Parents' Narratives of Social Withdrawal.

    Science.gov (United States)

    Rubinstein, Ellen

    2016-12-01

    Hikikomori, often glossed as "social withdrawal," emerged as a sociomedical condition among Japanese youth at the end of the twentieth century, and it continues to fascinate and concern the public. Explanatory frameworks for hikikomori abound, with different stakeholders attributing it to individual psychopathology, poor parenting, and/or a lack of social support structures. This article takes an interpretive approach to hikikomori by exploring parents' narrative constructions of hikikomori children in support group meetings and in-depth interviews. I argue that some parents were able to find hope in hikikomori by 'emplotting' their children's experiences into a larger narrative about onset, withdrawal, and recovery, which helped them remain invested in the present by maintaining a sense of possibility about the future. Contrary to literature that examines hikikomori as an epidemic of isolated individuals, I demonstrate how parents play a key role in hikikomori through meaning-making activities that have the potential to shape their children's experiences of withdrawal.

  14. Withdrawal of immunosuppresive agents in the treatment of disseminated coccidioidomycosis.

    Science.gov (United States)

    Kaplan, J E; Zoschke, D; Kisch, A L

    1980-04-01

    Disseminated coccidioidomycosis is a systemic fungal infection that causes high mortality in the renal transplatn patient. Cell-mediated immunity, which appears to be the relevant host defense mechanism, is impaired by the immunosupressive agents used to prevent allograft rejection. In the case presented, immunosuppressive therapy was stopped as an adjunct to treatment of this infection. The patient has shown evidence of improvement, and his allograft has continued to function nine months after the withdrawal of immunosuppressive therapy and 18 months after the diagnosis. In vitro lymphocyte function studies indicate that the impairment in cell-mediated immunity detected prior to withdrawal of immunosuppressive therapy has persisted, probably accounting for allograft survival. Withdrawal of immunosuppressive therapy may prolong survival in renal transplant patients with disseminated coccidioidomycosis. Additionally, depression in cell-mediated immunity associated with the fungal infection itself may be sufficient to prevent allograft rejection in these patients.

  15. Takotsubo Cardiomyopathy and Catatonia in the Setting of Benzodiazepine Withdrawal

    Directory of Open Access Journals (Sweden)

    Teng J. Peng

    2016-01-01

    Full Text Available We report two serious and unusual complications of benzodiazepine withdrawal in a single patient: takotsubo cardiomyopathy and catatonia. This 61-year-old female patient was brought to the emergency department with lethargy and within hours had declined into a state of catatonia. Although there was never a complaint of chest pain, ECG showed deep anterior T-wave inversions and cardiac enzymes were elevated. An echocardiogram was consistent with takotsubo cardiomyopathy. She later received 1 mg of midazolam and within minutes had resolution of catatonic symptoms. Careful history revealed that she had omitted her daily dose of lorazepam for 3 days prior to admission. To our knowledge, the case presented herein is the first report of simultaneous catatonia and takotsubo cardiomyopathy in the setting of benzodiazepine withdrawal. The pathogenesis of both conditions is poorly understood but may be indirectly related to the sudden decrease in γ-aminobutyric acid (GABA signaling during benzodiazepine withdrawal.

  16. Deadly pressure pneumothorax after withdrawal of misplaced feeding tube

    DEFF Research Database (Denmark)

    Andresen, Erik Nygaard; Frydland, Martin; Usinger, Lotte

    2016-01-01

    BACKGROUND: Many patients have a nasogastric feeding tube inserted during admission; however, misplacement is not uncommon. In this case report we present, to the best of our knowledge, the first documented fatality from pressure pneumothorax following nasogastric tube withdrawal. CASE PRESENTATION......, but our patient died less than an hour after withdrawal. The autopsy report stated that cause of death was tension pneumothorax, which developed following withdrawal of the misplaced feeding tube. CONCLUSIONS: The indications for insertion of nasogastric feeding tubes are many and the procedure...... is considered harmless; however, if the tube is misplaced there is good reason to be cautious on removal as this can unmask puncture of the pleura eliciting pneumothorax and, as this case report shows, result in an ultimately deadly tension pneumothorax....

  17. Phenobarbital compared to benzodiazepines in alcohol withdrawal treatment

    DEFF Research Database (Denmark)

    Askgaard, Gro; Hallas, Jesper; Fink-Jensen, Anders

    2016-01-01

    BACKGROUND: Long-acting benzodiazepines such as chlordiazepoxide are recommended as first-line treatment for alcohol withdrawal. These drugs are known for their abuse liability and might increase alcohol consumption among problem drinkers. Phenobarbital could be an alternative treatment option......, possibly with the drawback of a more pronounced acute toxicity. We evaluated if phenobarbital compared to chlordiazepoxide decreased the risk of subsequent use of benzodiazepines, alcohol recidivism and mortality. METHODS: The study was a register-based cohort study of patients admitted for alcohol...... withdrawal 1998-2013 and treated with either phenobarbital or chlordiazepoxide. Patients were followed for one year. We calculated hazard ratios (HR) for benzodiazepine use, alcohol recidivism and mortality associated with alcohol withdrawal treatment, while adjusting for confounders. RESULTS: A total...

  18. On the relationship between Indian summer monsoon withdrawal and Indo-Pacific SST anomalies before and after 1976/1977 climate shift

    Energy Technology Data Exchange (ETDEWEB)

    Sabeerali, C.T.; Rao, Suryachandra A. [Indian Institute of Tropical Meteorology, Pune (India); Ajayamohan, R.S. [University of Victoria, Canadian Centre for Climate Modelling and Analysis, Victoria, BC (Canada); Murtugudde, Raghu [University of Maryland, Earth System Science Interdisciplinary Center, College Park, MD (United States)

    2012-08-15

    A clear shift in the withdrawal dates of the Indian Summer Monsoon is observed in the long term time series of rainfall data. Prior (posterior) to the 1976/1977 climate shift most of the withdrawal dates are associated with a late (an early) withdrawal. As a result, the length of the rainy season (LRS) over the Indian land mass has also undergone similar changes (i.e., longer (shorter) LRS prior (posterior) to the climate shift). In this study, probable reasons for this significant shift in withdrawal dates and the LRS are investigated using reanalysis/observed datasets and also with the help of an atmospheric general circulation model. Reanalysis/observational datasets indicate that prior to the climate shift the sea surface temperature (SST) anomalies in the eastern equatorial Pacific Ocean and the Arabian Sea exerted a strong influence on both the withdrawal and the LRS. After the climate shift, the influence of the eastern equatorial Pacific Ocean SST has decreased and surprisingly, the influence of the Arabian Sea SST is almost non-existent. On the other hand, the influence of the southeastern equatorial Indian Ocean has increased significantly. It is observed that the upper tropospheric temperature gradient over the dominant monsoon region has decreased and the relative influence of the Indian Ocean SST variability on the withdrawal of the Indian Summer Monsoon has increased in the post climate shift period. Sensitivity experiments with the contrasting SST patterns on withdrawal dates and the LRS in the pre- and post- climate shift scenarios, confirm the observational evidences presented above. (orig.)

  19. Memantine reverses social withdrawal induced by ketamine in rats.

    Science.gov (United States)

    Uribe, Ezequiel; Landaeta, José; Wix, Richard; Eblen, Antonio

    2013-03-01

    The objective of this study was to determine the effect of memantine on schizophrenia-like symptoms in a ketamine-induced social withdrawal model in rats. We examined therapeutic effects of memantine, an NMDA antagonist, and haloperidol, a classic antipsychotic drug, on this behavioral model. Administration of memantine (10 or 15 mg·kg(-1)) significantly reduced ketamine-induced social withdrawal, and this effect was more effective than that of haloperidol (0.25 mg·kg(-1)) by restoring the social interaction between rats with no modification in general motor activity. These results suggest that memantine could have a therapeutic potential for schizophrenia.

  20. Water withdrawals, use, and trends in Florida, 2010

    Science.gov (United States)

    Marella, Richard L.

    2014-01-01

    In 2010, the total amount of water withdrawn in Florida was estimated to be 14,988 million gallons per day (Mgal/d). Saline water accounted for 8,589 Mgal/d (57 percent) and freshwater accounted for 6,399 Mgal/d (43 percent). Groundwater accounted for 4,166 Mgal/d (65 percent) of freshwater withdrawals, and surface water accounted for the remaining 2,233 Mgal/d (35 percent). Surface water accounted for nearly all (99.9 percent) saline-water withdrawals. An additional 659 Mgal/d of reclaimed wastewater was used in Florida during 2010. Freshwater withdrawals were greatest in Palm Beach County (707 Mgal/d), and saline-water withdrawals were greatest in Hillsborough County (1,715 Mgal/d). Fresh groundwater provided drinking water (public supplied and self-supplied) for 17.33 million people (92 percent of Florida’s population), and fresh surface water provided drinking water for 1.47 million people (8 percent). The statewide public-supply gross per capita use for 2010 was 134 gallons per day, whereas the statewide public-supply domestic per capita use was 85 gallons per day. The majority of groundwater withdrawals (almost 62 percent) in 2010 were obtained from the Floridan aquifer system, which is present throughout most of the State. The majority of fresh surface-water withdrawals (56 percent) came from the southern Florida hydrologic unit subregion and is associated with Lake Okeechobee and the canals in the Everglades Agricultural Area of Glades, Hendry, and Palm Beach Counties, as well as the Caloosahatchee River and its tributaries in the agricultural areas of Collier, Glades, Hendry, and Lee Counties. Overall, agricultural irrigation accounted for 40 percent of the total freshwater withdrawals (ground and surface), followed by public supply with 35 percent. Public supply accounted for 48 percent of groundwater withdrawals, followed by agricultural self-supplied (34 percent), commercial-industrial-mining self-supplied (7 percent), recreational

  1. John Strong - 1941-2006

    CERN Multimedia

    2006-01-01

    Our friend and colleague John Strong was cruelly taken from us by a brain tumour on 31 July, a few days before his 65th birthday. John started his career and obtained his PhD in a group from Westfield College, initially working on experiments at Rutherford Appleton Laboratory (RAL). From the early 1970s onwards, however, his research was focused on experiments in CERN, with several particularly notable contributions. The Omega spectrometer adopted a system John had originally developed for experiments at RAL using vidicon cameras (a type of television camera) to record the sparks in the spark chambers. This highly automated system allowed Omega to be used in a similar way to bubble chambers. He contributed to the success of NA1 and NA7, where he became heavily involved in the electronic trigger systems. In these experiments the Westfield group joined forces with Italian colleagues to measure the form factors of the pion and the kaon, and the lifetime of some of the newly discovered charm particles. Such h...

  2. Transport phenomena in strongly correlated Fermi liquids

    CERN Document Server

    Kontani, Hiroshi

    2013-01-01

    In conventional metals, various transport coefficients are scaled according to the quasiparticle relaxation time, \\tau, which implies that the relaxation time approximation (RTA) holds well. However, such a simple scaling does not hold in many strongly correlated electron systems, reflecting their unique electronic states. The most famous example would be cuprate high-Tc superconductors (HTSCs), where almost all the transport coefficients exhibit a significant deviation from the RTA results. To better understand the origin of this discrepancy, we develop a method for calculating various transport coefficients beyond the RTA by employing field theoretical techniques. Near the magnetic quantum critical point, the current vertex correction (CVC), which describes the electron-electron scattering beyond the relaxation time approximation, gives rise to various anomalous transport phenomena. We explain anomalous transport phenomena in cuprate HTSCs and other metals near their magnetic or orbital quantum critical poi...

  3. Withdrawal of anticancer therapy in advanced disease: a systematic literature review.

    Science.gov (United States)

    Clarke, G; Johnston, S; Corrie, P; Kuhn, I; Barclay, S

    2015-11-11

    Current guidelines set out when to start anticancer treatments, but not when to stop as the end of life approaches. Conventional cytotoxic agents are administered intravenously and have major life-threatening toxicities. Newer drugs include molecular targeted agents (MTAs), in particular, small molecule kinase-inhibitors (KIs), which are administered orally. These have fewer life-threatening toxicities, and are increasingly used to palliate advanced cancer, generally offering additional months of survival benefit. MTAs are substantially more expensive, between £2-8 K per month, and perceived as easier to start than stop. A systematic review of decision-making concerning the withdrawal of anticancer drugs towards the end of life within clinical practice, with a particular focus on MTAs. Nine electronic databases searched. PRISMA guidelines followed. Forty-two studies included. How are decisions made? Decision-making was shared and ongoing, including stopping, starting and trying different treatments. Oncologists often experienced 'professional role dissonance' between their self-perception as 'treaters', and talking about end of life care. Why are decisions made? Clinical factors: disease progression, worsening functional status, treatment side-effects. Non-clinical factors: physicians' personal experience, values, emotions. Some patients continued treatment to maintain 'hope', often reflecting limited understanding of palliative goals. When are decisions made? Limited evidence reveals patients' decisions based upon quality of life benefits. Clinicians found timing withdrawal particularly challenging. Who makes the decisions? Decisions were based within physician-patient interaction. Oncologists report that decisions around stopping chemotherapy treatment are challenging, with limited evidence-based guidance outside of clinical trial protocols. The increasing availability of oral MTAs is transforming the management of incurable cancer; blurring boundaries between

  4. Water Withdrawals, Use, and Trends in Florida, 2005

    Science.gov (United States)

    Marella, Richard L.

    2009-01-01

    In 2005, the total amount of water withdrawals in Florida was estimated at 18,359 million gallons per day (Mgal/d). Saline water accounted for 11,486 Mgal/d (63 percent), and freshwater accounted for 6,873 Mgal/d (37 percent). Groundwater accounted for 4,247 Mgal/d (62 percent) of freshwater withdrawals, and surface water accounted for the remaining 2,626 Mgal/d (38 percent). Surface water accounted for nearly all (99.9 percent) saline-water withdrawals. An additional 660 Mgal/d of reclaimed wastewater was used in Florida during 2005. The largest amount of freshwater was withdrawn from Palm Beach County, and the largest amount of saline water was withdrawn from Pasco County. Fresh groundwater provided drinking water (public supplied and self-supplied) for 16.19 million people (90 percent of Florida's population), and fresh surface water provided drinking water for 1.73 million people (10 percent). The majority of groundwater withdrawals (nearly 60 percent) in 2005 was obtained from the Floridan aquifer system which is present throughout the entire State. The majority of fresh surface-water withdrawals (59 percent) came from the southern Florida hydrologic unit subregion and is associated with Lake Okeechobee and the canals in the Everglades Agricultural Area of Glades, Hendry, and Palm Beach Counties, as well as the Caloosahatchee River and its tributaries in the agricultural areas of Collier, Glades, Hendry, and Lee Counties. Overall, agricultural irrigation accounted for 40 percent of the total freshwater withdrawals (ground and surface), followed by public supply with 37 percent. Public supply accounted for 52 percent of groundwater withdrawals, followed by agricultural self-supplied (31 percent), ommercial-industrial-mining self-supplied (8.5 percent), recreational irrigation and domestic self-supplied (4 percent each), and power generation (0.5 percent). Agricultural self-supplied accounted for 56 percent of fresh surface-water withdrawals, followed by power

  5. Observation of the Strong Electronic Coupling in Near-Infrared-Absorbing Tetraferrocene aza-Dipyrromethene and aza-BODIPY with Direct Ferrocene-α- and Ferrocene-β-Pyrrole Bonds: Toward Molecular Machinery with Four-Bit Information Storage Capacity.

    Science.gov (United States)

    Zatsikha, Yuriy V; Holstrom, Cole D; Chanawanno, Kullapa; Osinski, Allen J; Ziegler, Christopher J; Nemykin, Victor N

    2017-01-17

    The 1,3,7,9-tetraferrocenylazadipyrromethene (3) and the corresponding 1,3,5,7-tetraferrocene aza-BODIPY (4) were prepared via three and four synthetic steps, respectively, starting from ferrocenecarbaldehyde using the chalcone-type synthetic methodology. The novel tetra-iron compounds have ferrocene groups directly attached to both the α- and the β-pyrrolic positions, and the shortest Fe-Fe distance determined by X-ray crystallography for 3 was found to be ∼6.98 Å. These new compounds were characterized by UV-vis, nuclear magnetic resonance, and high-resolution electrospray ionization mass spectrometry methods, while metal-metal couplings in these systems were probed by electro- and spectroelectrochemistry, chemical oxidations, and Mössbauer spectroscopy. Electrochemical data are suggestive of the well-separated stepwise oxidations of all four ferrocene groups in 3 and 4, while spectroelectrochemical and chemical oxidation experiments allowed for characterization of the mixed-valence forms in the target compounds. Intervalence charge-transfer band analyses indicate that the mixed-valence [3] + and [4] + complexes belong to the weakly coupled class II systems in the Robin-Day classification. This interpretation was further supported by Mössbauer spectroscopy in which two individual doublets for Fe(II) and Fe(III) centers were observed in room-temperature experiments for the mixed-valence [3] n+ and [4] n+ species (n = 1-3). The electronic structure, redox properties, and UV-vis spectra of new systems were correlated with Density Functional Theory (DFT) and time-dependent DFT calculations (TDDFT), which are suggestive of a ferrocene-centered highest occupied molecular orbital and chromophore-centered lowest unoccupied molecular orbital in 3 and 4 as well as predominant spin localization at the ferrocene fragment attached to the α-pyrrolic positions in [3] + and [4] + .

  6. Sports Participation and Withdrawal: A Developmental Motivational Commentary.

    Science.gov (United States)

    Hom, Larry L.

    1996-01-01

    Examines the nature of adolescents' sports involvement as reflected in reasons for participation and withdrawal. Claims that the degree of fun, the motivation to attain competence, and the capacity to distinguish ability from effort are important. Concludes that if the goal of sports is to foster a healthy lifestyle, the issue of maximizing…

  7. Opiate withdrawal syndrome in buprenorphine abusers admitted to ...

    African Journals Online (AJOL)

    The sex v time interaction and the mode of consumption of buprenorphine had significant ... and cancer patients. .... The anal- ysis of the main simple effects revealed a significant ef- fect of time on withdrawal scores for both men (F=65.4,.

  8. Study of possible reduction or withdrawal of vitamin premix during ...

    African Journals Online (AJOL)

    Jane

    2011-07-06

    Jul 6, 2011 ... The effect of dietary vitamin premix withdrawal or reduction between 29 and 35, 36 and 42, and 29 and. 42 days of age on broiler chicken performance and immunocompetence was evaluated. The diets were formulated based on wheat and barley, and the experiment was conducted in floor pens ...

  9. A 'symptom-triggered' approach to alcohol withdrawal management.

    Science.gov (United States)

    Murdoch, Jay; Marsden, Janet

    In acute hospital settings, alcohol withdrawal often causes significant management problems and complicates a wide variety of concurrent conditions, placing a huge burden on the NHS. A significant number of critical incidents around patients who were undergoing detoxification in a general hospital setting led to the need for a project to implement and evaluate an evidence-based approach to the management of alcohol detoxification-a project that included a pre-intervention case note audit, the implementation of an evidence-based symptom-triggered detoxification protocol, and a post-intervention case note audit. This change in practice resulted in an average reduction of almost 60% in length of hospital stay and a 66% reduction in the amount of chlordiazepoxide used in detoxification, as well as highlighting that 10% of the sample group did not display any signs of withdrawal and did not require any medication. Even with these reductions, no patient post-intervention developed any severe signs of withdrawal phenomena, such as seizures or delirium tremens. The savings to the trust (The Pennine Acute Hospital Trust) are obvious,but the development of a consistent, quality service will lead to fewer long-term negative effects for patients that can be caused by detoxification. This work is a project evaluation of a locally implemented strategy, which, it was hypothesised,would improve care by providing an individualised treatment plan for the management of alcohol withdrawal symptoms.

  10. 29 CFR 1956.24 - Procedures for withdrawal of approval.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 9 2010-07-01 2010-07-01 false Procedures for withdrawal of approval. 1956.24 Section 1956.24 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION... do so, at least developmentally), no industrial or occupational issues may be considered a separable...

  11. Nontraditional Student Withdrawal from Undergraduate Accounting Programmes: A Holistic Perspective

    Science.gov (United States)

    Fortin, Anne; Sauvé, Louise; Viger, Chantal; Landry, France

    2016-01-01

    A collaborative project of several Quebec universities, this study investigates nontraditional student withdrawal from undergraduate accounting programmes. A nontraditional student is older than 24, or is a commuter or a part-time student, or combines some of these characteristics. Univariate and multivariate analyses of student dropout factors…

  12. 37 CFR 2.19 - Revocation or withdrawal of attorney.

    Science.gov (United States)

    2010-07-01

    ...., a corporate officer or general partner of a partnership). In the case of joint applicants or joint... a trademark case may withdraw upon application to and approval by the Director or, when applicable..., DEPARTMENT OF COMMERCE RULES OF PRACTICE IN TRADEMARK CASES Representation by Attorneys Or Other Authorized...

  13. Should Colleges Withdraw Students Who Threaten or Attempt Suicide?

    Science.gov (United States)

    Pavela, Gary

    2005-01-01

    This article discusses the pros and cons of "involuntary withdrawals" in cases of students who are at risk of suicide. A June, 2005, Massachusetts Superior Court summary judgment ruling in the case of "Shin v. Massachusetts Institute of Technology (MIT)" concluded that MIT administrators owed a duty of care to suicide victim,…

  14. Study of possible reduction or withdrawal of vitamin premix during ...

    African Journals Online (AJOL)

    The effect of dietary vitamin premix withdrawal or reduction between 29 and 35, 36 and 42, and 29 and 42 days of age on broiler chicken performance and immunocompetence was evaluated. The diets were formulated based on wheat and barley, and the experiment was conducted in floor pens (experiment 1) and battery ...

  15. 46 CFR 391.7 - Tax treatment of nonqualified withdrawals.

    Science.gov (United States)

    2010-10-01

    ... the Code. In lieu of the interest and additions to tax under such sections, simple interest on the... income, and the payment of interest with respect to such amounts. (b) Nonqualified withdrawals defined... in the fund), see § 391.4(e). (e) Interest. (1) For the period on or before the last date prescribed...

  16. 26 CFR 3.7 - Tax treatment of nonqualified withdrawals.

    Science.gov (United States)

    2010-04-01

    ... and additions to tax under such sections, simple interest on the amount of the tax attributable to any... payment of interest with respect to such amounts. (b) Nonqualified withdrawals defined. Except as provided...(e). (e) Interest. (1) For the period on or before the last date prescribed by law, including...

  17. Occupational Asthma after Withdrawal from the Occupational Allergen Exposure

    Czech Academy of Sciences Publication Activity Database

    Klusáčková, P.; Pelclová, D.; Lebedová, J.; Marečková, H.; Brabec, Marek

    2006-01-01

    Roč. 44, č. 4 (2006), s. 629-638 ISSN 0019-8366 Source of funding: V - iné verejné zdroje Keywords : occupational asthma * allergen exposure withdrawal Subject RIV: BB - Applied Statistics, Operational Research Impact factor: 0.911, year: 2006 http://www.jniosh.go.jp/en/indu_hel/pdf/indhealth_44_4_629.pdf

  18. Social Withdrawal Subtypes during Early Adolescence in India

    Science.gov (United States)

    Bowker, Julie C.; Raja, Radhi

    2011-01-01

    The overarching goal of this study was to examine the associations between three social withdrawal subtypes (shyness, unsociability, avoidance), peer isolation, peer difficulties (victimization, rejection, exclusion, low acceptance), and loneliness in India during early adolescence. Participants were 194 adolescents in Surat, India (M age=13.35…

  19. Social Anxiety and Adolescents' Friendships: The Role of Social Withdrawal

    Science.gov (United States)

    Biggs, Bridget K.; Vernberg, Eric M.; Wu, Yelena P.

    2012-01-01

    Research indicates social anxiety is associated with lower friendship quality, but little is known about the underlying mechanisms. This 2-month longitudinal study examined social withdrawal as a mediator of the social anxiety-friendship quality link in a sample of 214 adolescents (M[subscript age] = 13.1 years, SD = 0.73) that included an…

  20. Young Children's Perceptions of Social Withdrawal in China and Canada

    Science.gov (United States)

    Coplan, Robert J.; Zheng, Shujie; Weeks, Murray; Chen, Xinyin

    2012-01-01

    The goal of the present study was to explore attitudes and responses to different forms of social withdrawal in China and Canada. Participants in this study were children in early elementary school in the People's Republic of China (n = 213; 113 boys, 100 girls, M[subscript age] = 6.11 years) and Canada (n = 162; 60 boys, 102 girls, M[subscript…

  1. The social side of shame : approach versus withdrawal

    NARCIS (Netherlands)

    de Hooge, Ilona E.; Breugelmans, Seger M.; Wagemans, Fieke M.A.; Zeelenberg, Marcel

    2018-01-01

    At present, the consequences and functions of experiences of shame are not yet well understood. Whereas psychology literature typically portrays shame as being bad for social relations, motivating social avoidance and withdrawal, there are recent indications that shame can be reinterpreted as having

  2. The social side of shame: approach versus withdrawal

    NARCIS (Netherlands)

    Hooge, De Ilona E.; Breugelmans, Seger M.; Wagemans, Fieke M.A.; Zeelenberg, Marcel

    2018-01-01

    At present, the consequences and functions of experiences of shame are not yet well understood. Whereas psychology literature typically portrays shame as being bad for social relations, motivating social avoidance and withdrawal, there are recent indications that shame can be reinterpreted as having

  3. Evolution of Metabolic Abnormalities in Alcoholic Patients during Withdrawal

    Directory of Open Access Journals (Sweden)

    X. Vandemergel

    2015-01-01

    Full Text Available Chronic alcohol intoxication is accompanied by metabolic abnormalities. Evolution during the early withdrawal period has been poorly investigated. The aim of this study was to determine the evolution of metabolic parameters during alcohol withdrawal. Patients and Methods. Thirty-three patients admitted in our department for alcohol withdrawal were prospectively included. Results. Baseline hypophosphatemia was found in 24% of cases. FEPO4 was reduced from 14.2 ± 9% at baseline to 7.3 ± 4.2% at day 3 (Pnl, respectively. No correlation was found between the sodium and CPK levels (P=0.75 nor between the CPK level and the amount of alcohol ingested (rs = 0.084, P=0.097. Baseline urate level was elevated and returned to normal after three days. Baseline magnesium concentration was normal and stable over time. Conclusion. Chronic alcohol intoxication was accompanied by phosphaturia, rapidly reversible after alcohol withdrawal and inversely correlated with albuminemia, slight hyponatremia, low levels of 25 hydroxy vitamin D, elevated CPK level in about 30% of women, and hyperuricemia with rapid normalization.

  4. Parents, Peers, and Social Withdrawal in Childhood: A Relationship Perspective

    Science.gov (United States)

    Rubin, Kenneth H.; Root, Amy Kennedy; Bowker, Julie

    2010-01-01

    In this chapter, the authors review the history of the Waterloo Longitudinal Project (WLP), the first longitudinal study (1980-1992) dedicated to the study of social withdrawal, its correlates, and consequences. Theories underlying the WLP are described, as are its empirical findings. Recent research from other labs that has extended the findings…

  5. The impact of withdrawal rofecoxib on NSAIDs utilization

    NARCIS (Netherlands)

    Atthobari, J.; Boersma, C.; Visser, S.T.; Postma, M.J.; De Jong-Van Den Berg, L.T.W.

    2010-01-01

    Background: Pharmacovigilance is an important tool to gather real-life information on effectiveness and adverse effects of drugs. Therefore, post-marketing study can lead to new therapeutic insights or even market withdrawal. In September 2004, rofecoxib was withdrawn from the market for reasons of

  6. 18 CFR 801.3 - Allocations, diversions, withdrawals and release.

    Science.gov (United States)

    2010-04-01

    ... wherein the demands upon supply made by water users have developed or threaten to develop to such a degree..., or withdrawals of water be based on the common law principles of riparian rights which entitles... actual and immediate shortage of available and usable water supply, determine and delineate the area of...

  7. 17 CFR 41.47 - Withdrawal of margin.

    Science.gov (United States)

    2010-04-01

    ... PRODUCTS Customer Accounts and Margin Requirements § 41.47 Withdrawal of margin. (a) By the customer... positions in the account under this Regulation (Subpart E, §§ 41.42 through 41.49). (b) By the security...) Interest charged on credit maintained in the account; (3) Communication or shipping charges with respect to...

  8. 9 CFR 355.38 - Withdrawal of service.

    Science.gov (United States)

    2010-01-01

    ... INSPECTION AND CERTIFICATION CERTIFIED PRODUCTS FOR DOGS, CATS, AND OTHER CARNIVORA; INSPECTION... 9 Animals and Animal Products 2 2010-01-01 2010-01-01 false Withdrawal of service. 355.38 Section 355.38 Animals and Animal Products FOOD SAFETY AND INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE...

  9. Effects of Nicotine Metabolites on Nicotine Withdrawal Behaviors in Mice.

    Science.gov (United States)

    Elhassan, Sagi; Bagdas, Deniz; Damaj, M Imad

    2017-06-01

    Rodent studies suggest that nicotine metabolites and minor tobacco alkaloids such as nornicotine and cotinine may promote cigarette smoking by enhancing nicotine rewarding and reinforcing effects. However, there is little information on the effects of these minor tobacco alkaloids on nicotine withdrawal. The present studies were conducted to determine whether the minor tobacco alkaloids nornicotine and cotinine exhibit nicotine-like behavioral effects in a mouse model of spontaneous nicotine withdrawal. Mice were infused with nicotine or saline for 14 days. Experiments were conducted on day 15, 18-24 hours after minipump removal. Ten minutes prior to testing, nicotine-dependent ICR male mice received an acute injection of nicotine (0.05 and 0.5 mg/kg), nornicotine (2.5 and 25 mg/kg), or cotinine (5 and 50 mg/kg) to determine effects on somatic signs, anxiety-like behaviors, and hyperalgesia spontaneous signs of withdrawal. Nicotine and the minor tobacco alkaloid nornicotine, but not cotinine, produced dose-dependent reversal of nicotine withdrawal signs in the mouse. The minor tobacco alkaloid and nicotine metabolite nornicotine at high doses have nicotinic like effects that may contribute to tobacco consumption and dependence. © The Author 2017. Published by Oxford University Press on behalf of the Society for Research on Nicotine and Tobacco. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  10. 47 CFR 76.917 - Notification of certification withdrawal.

    Science.gov (United States)

    2010-10-01

    ... certification withdrawal. A franchising authority that has been certified to regulate rates may, at any time... include the franchising authority's determination that rate regulation no longer serves the interests of cable subscribers served by the cable system within the franchising authority's jurisdiction, and that...

  11. Temporal Withdrawal Behaviors in an Educational Policy Context

    Science.gov (United States)

    Rosenblatt, Zehava; Shapira-Lishchinsky, Orly

    2017-01-01

    Purpose: The purpose of this paper is to investigate the differential relations between two teacher withdrawal behaviors: work absence and lateness, and two types of school ethics: organizational justice (distributive, procedural) and ethical climate (formal, caring), all in the context of school turbulent environment. Design/methodology/approach:…

  12. Withdrawal cognition among workers in distressed banks: Roles of ...

    African Journals Online (AJOL)

    Results indicated that employees who perceived low organisational support and high inequality had high level of withdrawal cognition. Based on these findings, the researchers recommended that bank managers should provide adequate social supports for their employees and treat them equally or make sure that rewards ...

  13. 46 CFR 391.6 - Tax treatment of qualified withdrawals.

    Science.gov (United States)

    2010-10-01

    ... accounting whereby (1) payments shall reduce the basis of the property on the day such payments are actually... 46 Shipping 8 2010-10-01 2010-10-01 false Tax treatment of qualified withdrawals. 391.6 Section...-469 FEDERAL INCOME TAX ASPECTS OF THE CAPITAL CONSTRUCTION FUND § 391.6 Tax treatment of qualified...

  14. Withdrawal from the International Criminal Court: Does Africa have ...

    African Journals Online (AJOL)

    After a century in the making, the International Criminal Court (ICC) came into existence in 2002 with an overwhelming number of states ratifying the Rome Statute. With 34 signatories, Africa is the largest contributor in the Assembly of State Parties, yet Africa has become its severest critic. As threats of withdrawal become a ...

  15. Steroid withdrawal in renal transplant patients: the Irish experience.

    LENUS (Irish Health Repository)

    Phelan, P J

    2010-10-29

    BACKGROUND: Steroid therapy is associated with significant morbidity in renal transplant recipients. However, there is concern that steroid withdrawal will adversely affect outcome. METHODS: We report on 241 renal transplant recipients on different doses of corticosteroids at 3 months (zero, ≤5 mg\\/day, >5 mg\\/day). Parameters analysed included blood pressure, lipid profile, weight change, new onset diabetes after transplantation (NODAT), allograft survival and acute rejection. RESULTS: Elimination of corticosteroids had no impact on allograft survival at 1 year. There were no cases of NODAT in the steroid withdrawal group compared with over 7% in each of the steroid groups. There were no significant improvements in weight gain, blood pressure control or total cholesterol with withdrawal of steroids before 3 months. CONCLUSIONS: In renal transplant patients treated with tacrolimus and mycophenolate, early withdrawal of steroids does not appear to adversely affect allograft outcome at 1 year. It may result in less NODAT.

  16. 9 CFR 362.4 - Denial or withdrawal of service.

    Science.gov (United States)

    2010-01-01

    ... 9 Animals and Animal Products 2 2010-01-01 2010-01-01 false Denial or withdrawal of service. 362.4 Section 362.4 Animals and Animal Products FOOD SAFETY AND INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE..., assaults, abuse, or any other improper means; (iv) has knowingly falsely made, issued, altered, forged, or...

  17. Withdrawal Strength and Bending Yield Strength of Stainless Steel Nails

    Science.gov (United States)

    Douglas R. Rammer; Samuel L. Zelinka

    2015-01-01

    It has been well established that stainless steel nails have superior corrosion performance compared to carbon steel or galvanized nails in treated wood; however, their mechanical fastening behavior is unknown. In this paper, the performance of stainless steel nails is examined with respect to two important properties used in wood connection design: withdrawal strength...

  18. A Case Report of Severe Delirium after Amantadine Withdrawal

    Directory of Open Access Journals (Sweden)

    Franz Marxreiter

    2017-03-01

    Full Text Available Amantadine is frequently used in addition to dopaminergic substances like dopamine agonists or L-Dopa in advanced Parkinson disease (PD. However, adverse effects like hallucinations limit its use. PD patients developing severe psychotic symptoms upon treatment with either dopaminergic substances and/or amantadine need to stop intake of any psychotropic substance. Here, we report the case of a 71-year-old PD patient without previously known cognitive impairment. He presented with drug-induced psychotic symptoms due to changes in his therapeutic regimen (increase in COMT inhibitors, newly introduced MAO B inhibitors. Also, amantadine had been part of his long-term medication for more than 2 years. The severity of his psychotic symptoms required a L-Dopa monotherapy. After changing his medication, the patient developed severe delirium that resolved rapidly after i.v. amantadine infusion, suggesting an amantadine withdrawal syndrome. Amantadine withdrawal syndrome is a rare adverse event that may present even in PD patients without cognitive impairment. This case report highlights the need for a gradual withdrawal of amantadine even if acute and severe psychotic symptoms are present. Moreover, this is the first report of a cognitively unimpaired patient developing an amantadine withdrawal syndrome.

  19. The pathogenesis of propranolol-withdrawal syndrome in essential hypertension.

    Science.gov (United States)

    Kristensen, B O; Steiness, E; Weeke, J

    1979-12-01

    1. In hypertension, the beta-adrenoreceptor-blocker-withdrawal syndrome comprises tachycardia, sweating, tremor and general malaise, symptoms resembling thyrotoxicosis. 2. The effect of abrupt cessation of propranolol on serum concentrations of thyroxine (T4) and triiodothyronine (T3) was therefore investigated in five patients with uncomplicated essential hypertension, treated with propranolol in doses from 160 to 480 mg/day. 3. Four of the five patients developed one or more of the above-mentioned symptoms within 2-6 days after withdrawal of propranolol. 4. A mean relative increase in serum free T3 of 51% (range 22-74%) was found in these four patients on the day of onset of symptoms. 5. The increase in free T3 in the five patients correlated positively with total serum propranolol on the last day the drug was given (r = 0.91, 2P = 0.03). 6. As an increase in T3 was found only in patients suffering the withdrawal syndrome, and was maximal the day the symptoms appeared, despite a variation in time of onset from 2 to 6 days, it is suggested that the beta-adrenoreceptor-blocker-withdrawal syndrome, at least partially, is caused by rebound increased production of T3, induced by the well-known inhibition of the monodeiodination of T4 to T3 during beta-adrenoreceptor blockade. 7. This assumption may explain the clinical symptoms and the reported transient increased beta-adrenoreceptor sensitivity with unchanged serum concentrations of catecholamines.

  20. 18 CFR 806.23 - Standards for water withdrawals.

    Science.gov (United States)

    2010-04-01

    ...) Investigate additional sources or storage options to meet the demand of the project. (ii) Submit a water... 18 Conservation of Power and Water Resources 2 2010-04-01 2010-04-01 false Standards for water withdrawals. 806.23 Section 806.23 Conservation of Power and Water Resources SUSQUEHANNA RIVER BASIN...