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Sample records for induces strong anti-sense

  1. Rcs signalling-activated transcription of rcsA induces strong anti-sense transcription of upstream fliPQR flagellar genes from a weak intergenic promoter: regulatory roles for the anti-sense transcript in virulence and motility.

    PubMed

    Wang, Qingfeng; Harshey, Rasika M

    2009-10-01

    In Salmonella enterica, an activated Rcs signalling system inhibits initiation of transcription of the flhD master operon. Under these conditions, where motility is shut down, microarray experiments showed an increased RNA signal for three flagellar genes -fliPQR- located upstream of rcsA. We show here that it is the anti-sense (AS) strand of these genes that is transcribed, originating at a weak promoter in the intergenic region between fliR and rcsA. RcsA is an auxiliary regulator for the Rcs system, whose transcription is dependent on the response regulator RcsB. Rcs-activated rightward transcription, but not translation, of rcsA is required for stimulation of leftward AS transcription. Our results implicate a combined action of RcsB and rcsA transcription in activating the AS promoter, likely by modulating DNA superhelicity in the intergenic region. We show that the AS transcript regulates many genes in the Rcs regulon, including SPI-1 and SPI-2 virulence and stress-response genes. In the wild-type strain the AS transcript is present in low amounts, independent of Rcs signalling. Here, AS transcription modulates complementary sense RNA levels and impacts swarming motility. It appears that the flagellar AS transcript has been co-opted by the Rcs system to regulate virulence.

  2. Upregulation of long non-coding RNA HIF 1α-anti-sense 1 induced by transforming growth factor-β-mediated targeting of sirtuin 1 promotes osteoblastic differentiation of human bone marrow stromal cells

    PubMed Central

    XU, YAO; WANG, SHILONG; TANG, CHAOLIANG; CHEN, WENJUN

    2015-01-01

    The present study aimed to investigate the regulatory mechanism of long non-coding RNA hypoxia-inducible factor 1α-anti-sense 1 (lncRNA HIF1α-AS1) in osteoblast differentiation as well as its targeting by sirtuin 1 (SIRT1), which may be inhibited by transforming growth factor (TGF)-β in bone marrow stromal cells (BMSCs). Real-time polymerase chain reaction (PCR), western blot analysis, lncRNA PCR arrays and chromatin immunoprecipitation were performed in order to examine the interference of SIRT1 expression by TGF-β, the effects of SIRT1 overexpression on lncRNA HIF1α-AS1 and the regulation of the expression of homeobox (HOX)D10, which promotes BMSC differentiation, by lncRNA HIF1α-AS1. The results showed that TGF-β interfered with SIRT1 expression. Furthermore, lncRNA HIF1α-AS1 was significantly downregulated following overexpression of SIRT1. In addition, low expression of HIF1α-AS1 was sufficient to block the expression of HOXD10. The present study further demonstrated that downregulation of HOXD10 by HIF1α-AS1 interfered with acetylation, and subsequently resulted in the inhibition of osteoblast differentiation. These results suggested that HIF1α-AS1 is an essential mediator of osteoblast differentiation, and may thus represent a gene-therapeutic agent for the treatment of human bone diseases. PMID:26460121

  3. Strong correlation induced charge localization in antiferromagnets

    PubMed Central

    Zhu, Zheng; Jiang, Hong-Chen; Qi, Yang; Tian, Chushun; Weng, Zheng-Yu

    2013-01-01

    The fate of a hole injected in an antiferromagnet is an outstanding issue of strongly correlated physics. It provides important insights into doped Mott insulators closely related to high-temperature superconductivity. Here, we report a systematic numerical study of t-J ladder systems based on the density matrix renormalization group. It reveals a surprising result for the single hole's motion in an otherwise well-understood undoped system. Specifically, we find that the common belief of quasiparticle picture is invalidated by the self-localization of the doped hole. In contrast to Anderson localization caused by disorders, the charge localization discovered here is an entirely new phenomenon purely of strong correlation origin. It results from destructive quantum interference of novel signs picked up by the hole, and since the same effect is of a generic feature of doped Mott physics, our findings unveil a new paradigm which may go beyond the single hole doped system. PMID:24002668

  4. [Music-induced chills as a strong emotional experience].

    PubMed

    Mori, Kazuma; Iwanaga, Makoto

    2014-12-01

    While enjoying music and other works of art, people sometimes experience "chills," a strong emotional response characterized by a sensation of goose bumps or shivers. Such experiences differ from having goose bumps as a defense response or from shivering in reaction to cold temperatures. The current paper presents the phenomenon of music-induced chills and reviews the chill-related emotional response, autonomic nervous system activity, and brain activity. It also reviews the musico-acoustic features, listening contexts, and individual differences that cause chills. Based on the review, we propose a hypothetical model regarding the evocation of music-induced chills. Furthermore, we investigate the strong emotional response associated with chills by exploring the relationship between music-related chills and non-music-related chills, and discuss future research directions.

  5. Anomaly-Induced Dynamical Refringence in Strong-Field QED.

    PubMed

    Mueller, N; Hebenstreit, F; Berges, J

    2016-08-05

    We investigate the impact of the Adler-Bell-Jackiw anomaly on the nonequilibrium evolution of strong-field quantum electrodynamics (QED) using real-time lattice gauge theory techniques. For field strengths exceeding the Schwinger limit for pair production, we encounter a highly absorptive medium with anomaly induced dynamical refractive properties. In contrast to earlier expectations based on equilibrium properties, where net anomalous effects vanish because of the trivial vacuum structure, we find that out-of-equilibrium conditions can have dramatic consequences for the presence of quantum currents with distinctive macroscopic signatures. We observe an intriguing tracking behavior, where the system spends longest times near collinear field configurations with maximum anomalous current. Apart from the potential relevance of our findings for future laser experiments, similar phenomena related to the chiral magnetic effect are expected to play an important role for strong QED fields during initial stages of heavy-ion collision experiments.

  6. Magnetic moments induce strong phonon renormalization in FeSi

    PubMed Central

    Krannich, S.; Sidis, Y.; Lamago, D.; Heid, R.; Mignot, J.-M.; Löhneysen, H. v.; Ivanov, A.; Steffens, P.; Keller, T.; Wang, L.; Goering, E.; Weber, F.

    2015-01-01

    The interactions of electronic, spin and lattice degrees of freedom in solids result in complex phase diagrams, new emergent phenomena and technical applications. While electron–phonon coupling is well understood, and interactions between spin and electronic excitations are intensely investigated, only little is known about the dynamic interactions between spin and lattice excitations. Noncentrosymmetric FeSi is known to undergo with increasing temperature a crossover from insulating to metallic behaviour with concomitant magnetic fluctuations, and exhibits strongly temperature-dependent phonon energies. Here we show by detailed inelastic neutron-scattering measurements and ab initio calculations that the phonon renormalization in FeSi is linked to its unconventional magnetic properties. Electronic states mediating conventional electron–phonon coupling are only activated in the presence of strong magnetic fluctuations. Furthermore, phonons entailing strongly varying Fe–Fe distances are damped via dynamic coupling to the temperature-induced magnetic moments, highlighting FeSi as a material with direct spin–phonon coupling and multiple interaction paths. PMID:26611619

  7. Nanosized graphene crystallite induced strong magnetism in pure carbon films.

    PubMed

    Wang, Chao; Zhang, Xi; Diao, Dongfeng

    2015-03-14

    We report strong magnetism in pure carbon films grown by electron irradiation assisted physical vapor deposition in electron cyclotron resonance plasma. The development of graphene nanocrystallites in the amorphous film matrix, and the dependence of the magnetic behavior on amorphous, nanocrystallite and graphite-like structures were investigated. Results were that the amorphous structure shows weak paramagnetism, graphene nanocrystallites lead to strong magnetization, and graphite-like structures corresponded with a lower magnetization. At a room temperature of 300 K, the highest saturation magnetization of 0.37 emu g(-1) was found in the nanosized graphene nanocrystallite structure. The origin of strong magnetism in nanocrystallites was ascribed to the spin magnetic moment at the graphene layer edges.

  8. Higgs-induced spectroscopic shifts near strong gravity sources

    SciTech Connect

    Onofrio, Roberto

    2010-09-15

    We explore the consequences of the mass generation due to the Higgs field in strong gravity astrophysical environments. The vacuum expectation value of the Higgs field is predicted to depend on the curvature of spacetime, potentially giving rise to peculiar spectroscopic shifts, named hereafter 'Higgs shifts'. Higgs shifts could be searched through dedicated multiwavelength and multispecies surveys with high spatial and spectral resolution near strong gravity sources such as Sagittarius A* or broad searches for signals due to primordial black holes. The possible absence of Higgs shifts in these surveys should provide limits to the coupling between the Higgs particle and the curvature of spacetime, a topic of interest for a recently proposed Higgs-driven inflationary model. We discuss some conceptual issues regarding the coexistence between the Higgs mechanism and gravity, especially for their different handling of fundamental and composite particles.

  9. Strong Magnetic Field Induced Changes of Gene Expression in Arabidopsis

    NASA Astrophysics Data System (ADS)

    Paul, A.-L.; Ferl, R. J.; Klingenberg, B.; Brooks, J. S.; Morgan, A. N.; Yowtak, J.; Meisel, M. W.

    2005-07-01

    We review our studies of the biological impact of magnetic field strengths of up to 30 T on transgenic arabidopsis plants engineered with a stress response gene consisting of the alcohol dehydrogenase (Adh) gene promoter driving the β-glucuronidase (GUS) gene reporter. Field strengths in excess of 15 T induce expression of the Adh/GUS transgene in the roots and leaves. Microarray analyses indicate that such field strengths have a far reaching effect on the genome. Wide spread induction of stress-related genes and transcription factors, and a depression of genes associated with cell wall metabolism are prominent examples.

  10. Interface-induced magnetism and strong correlation in oxide heterostructures

    NASA Astrophysics Data System (ADS)

    Stemmer, Susanne

    2015-03-01

    Two-dimensional electron gases (2DEGs) at interfaces between two insulating oxides have attracted significant attention because they can exhibit unique properties, such as strong electron correlations, superconductivity and magnetism. In this presentation, we will discuss the emergent properties of 2DEGs in SrTiO3 quantum wells that are interfaced with Mott insulating rare earth titanates (RTiO3) . We show that the magnetic properties of the 2DEG can be tuned to be either (incipient) ferromagnetic or (incipient) antiferromagnetic, depending on the specific RTiO3 that interfaces it. The thickness of the quantum well is a critical tuning parameter and determines the onset of magnetism, the proximity to a quantum critical point, and the onset of non-Fermi liquid behavior for those quantum wells that are in proximity to an antiferromagnetic transition. We will also discuss the role of symmetry-lowering structural transitions in the quantum well.

  11. Moderately strong pump-induced ultrafast dynamics in solution

    NASA Astrophysics Data System (ADS)

    Shen, H. F.; Zhang, Yizhu; Yan, T.-M.; Wang, Z. Y.; Jiang, Y. H.

    2016-09-01

    The transient transmittance spectra of laser dye IR144 in methanol were investigated experimentally in the moderately strong pump-probe field. Observed emission spectra in the red edge of the incident-field bandwidth, created by resonant impulsive stimulated Raman scattering (RISRS), display significant nonlinear intensity dependence as the pulse intensity increases. Dynamic perspectives of RISRS spectra can be understood well in a wavepacket picture. The excitation of high vibrational levels in the ground electronic state leading to the redshift of emissions presents high dependence of the pump-pulse intensity and ultrafast dynamical features, mapping the spatial overlap and separation of ground and excited wave functions and resolving the ultrafast vibrational relaxation in the femtosecond regime.

  12. Irradiation strongly reduces tumorigenesis of human induced pluripotent stem cells.

    PubMed

    Inui, Shoki; Minami, Kazumasa; Ito, Emiko; Imaizumi, Hiromasa; Mori, Seiji; Koizumi, Masahiko; Fukushima, Satsuki; Miyagawa, Shigeru; Sawa, Yoshiki; Matsuura, Nariaki

    2017-03-03

    Induced pluripotent stem (iPS) cells have demonstrated they can undergo self-renewal, attain pluripotency, and differentiate into various types of functional cells. In clinical transplantation of iPS cells, however, a major problem is the prevention of tumorigenesis. We speculated that tumor formation could be inhibited by means of irradiation. Since the main purpose of this study was to explore the prevention of tumor formation in human iPS (hiPS) cells, we tested the effects of irradiation on tumor-associated factors such as radiosensitivity, pluripotency and cell death in hiPS cells. The irradiated hiPS cells showed much higher radiosensitivity, because the survival fraction of hiPS cells irradiated with 2 Gy was < 10%, and there was no change of pluripotency. Irradiation with 2 and 4 Gy caused substantial cell death, which was mostly the result of apoptosis. Irradiation with 2 Gy was detrimental enough to cause loss of proliferation capability and trigger substantial cell death in vitro. The hiPS cells irradiated with 2 Gy were injected into NOG mice (NOD/Shi-scid, IL-2 Rγnull) for the analysis of tumor formation. The group of mice into which hiPS cells irradiated with 2 Gy was transplanted showed significant suppression of tumor formation in comparison with that of the group into which non-irradiated hiPS cells were transplanted. It can be presumed that this diminished rate of tumor formation was due to loss of proliferation and cell death caused by irradiation. Our findings suggest that tumor formation following cell therapy or organ transplantation induced by hiPS cells may be prevented by irradiation.

  13. Skin temperature changes induced by strong static magnetic field exposure.

    PubMed

    Ichioka, Shigeru; Minegishi, Masayuki; Iwasaka, Masakazu; Shibata, Masahiro; Nakatsuka, Takashi; Ando, Joji; Ueno, Shoogo

    2003-09-01

    High intensity static magnetic fields, when applied to the whole body of the anesthetized rat, have previously been reported to decrease skin temperature. The hypothesis of the present study was that in diamagnetic water, molecules in the air play significant roles in the mechanism of skin temperature decrease. We used a horizontal cylindrical superconducting magnet. The magnet produced 8 T at its center. A thermistor probe was inserted in a subcutaneous pocket of the anesthetized rats to measure skin temperature. Animals (n=10) were placed in an open plastic holder in which the ambient air was free to move in any direction (group I). Animals (n=10) were placed in a closed holder in which the air circulation toward the direction of weak magnetic field was restricted (group II). Each holder was connected to a hydrometer to measure humidity around the animal in the holder. The data acquisition phase consisted of a 5 min baseline interval, followed by inserting the animal together with the holder into the center of the magnet bore for a 5 min exposure and a 5 min postexposure period outside the bore. In group I, skin temperature and humidity around the animal significantly decreased during exposure, followed by recovery after exposure. In group II, skin temperature and humidity did not decrease during the measurement. The skin temperature decrease was closely related to the decrease in humidity around the body of the animal in the holder, and the changes were completely blocked by restricting the air circulation in the direction of the bore entrance. Possible mechanisms responsible for the decrease in skin temperature may be associated with magnetically induced movement of water vapor at the skin surface, leading to skin temperature decrease.

  14. Energy Transport Induced by an External Alternating Field in Strongly Disordered Media

    SciTech Connect

    Burin, Alexander L.; Kagan, Yuri; Polishchuk, Il'ya Ya.

    2001-06-11

    The delocalization of excitations in an ensemble of two-level systems with a strong disorder due to an external alternating acoustic or electric field is considered. The propagating modes are shown to appear if a ratio of the field amplitude to the frequency is large enough. Two complementary approaches, the static one similar to that of Anderson and the dynamic one related to Landau-Zener, are developed. It is shown that the field-induced relaxation mechanism can have a strong influence on the kinetics. The internal friction is argued to be vastly affected by the relaxation mechanism proposed.

  15. Superconductivity in HfTe5 across weak to strong topological insulator transition induced via pressures

    NASA Astrophysics Data System (ADS)

    Liu, Y.; Long, Y. J.; Zhao, L. X.; Nie, S. M.; Zhang, S. J.; Weng, Y. X.; Jin, M. L.; Li, W. M.; Liu, Q. Q.; Long, Y. W.; Yu, R. C.; Gu, C. Z.; Sun, F.; Yang, W. G.; Mao, H. K.; Feng, X. L.; Li, Q.; Zheng, W. T.; Weng, H. M.; Dai, X.; Fang, Z.; Chen, G. F.; Jin, C. Q.

    2017-03-01

    Recently, theoretical studies show that layered HfTe5 is at the boundary of weak & strong topological insulator (TI) and might crossover to a Dirac semimetal state by changing lattice parameters. The topological properties of 3D stacked HfTe5 are expected hence to be sensitive to pressures tuning. Here, we report pressure induced phase evolution in both electronic & crystal structures for HfTe5 with a culmination of pressure induced superconductivity. Our experiments indicated that the temperature for anomaly resistance peak (Tp) due to Lifshitz transition decreases first before climbs up to a maximum with pressure while the Tp minimum corresponds to the transition from a weak TI to strong TI. The HfTe5 crystal becomes superconductive above ~5.5 GPa where the Tp reaches maximum. The highest superconducting transition temperature (Tc) around 5 K was achieved at 20 GPa. Crystal structure studies indicate that HfTe5 transforms from a Cmcm phase across a monoclinic C2/m phase then to a P-1 phase with increasing pressure. Based on transport, structure studies a comprehensive phase diagram of HfTe5 is constructed as function of pressure. The work provides valuable experimental insights into the evolution on how to proceed from a weak TI precursor across a strong TI to superconductors.

  16. Superconductivity in HfTe5 across weak to strong topological insulator transition induced via pressures

    PubMed Central

    Liu, Y.; Long, Y. J.; Zhao, L. X.; Nie, S. M.; Zhang, S. J.; Weng, Y. X.; Jin, M. L.; Li, W. M.; Liu, Q. Q.; Long, Y. W.; Yu, R. C.; Gu, C. Z.; Sun, F.; Yang, W. G.; Mao, H. K.; Feng, X. L.; Li, Q.; Zheng, W. T.; Weng, H. M.; Dai, X.; Fang, Z.; Chen, G. F.; Jin, C. Q.

    2017-01-01

    Recently, theoretical studies show that layered HfTe5 is at the boundary of weak & strong topological insulator (TI) and might crossover to a Dirac semimetal state by changing lattice parameters. The topological properties of 3D stacked HfTe5 are expected hence to be sensitive to pressures tuning. Here, we report pressure induced phase evolution in both electronic & crystal structures for HfTe5 with a culmination of pressure induced superconductivity. Our experiments indicated that the temperature for anomaly resistance peak (Tp) due to Lifshitz transition decreases first before climbs up to a maximum with pressure while the Tp minimum corresponds to the transition from a weak TI to strong TI. The HfTe5 crystal becomes superconductive above ~5.5 GPa where the Tp reaches maximum. The highest superconducting transition temperature (Tc) around 5 K was achieved at 20 GPa. Crystal structure studies indicate that HfTe5 transforms from a Cmcm phase across a monoclinic C2/m phase then to a P-1 phase with increasing pressure. Based on transport, structure studies a comprehensive phase diagram of HfTe5 is constructed as function of pressure. The work provides valuable experimental insights into the evolution on how to proceed from a weak TI precursor across a strong TI to superconductors. PMID:28300156

  17. Electric-field-induced strong enhancement of electroluminescence in multilayer molybdenum disulfide

    PubMed Central

    Li, Dehui; Cheng, Rui; Zhou, Hailong; Wang, Chen; Yin, Anxiang; Chen, Yu; Weiss, Nathan O.; Huang, Yu; Duan, Xiangfeng

    2015-01-01

    The layered transition metal dichalcogenides have attracted considerable interest for their unique electronic and optical properties. While the monolayer MoS2 exhibits a direct bandgap, the multilayer MoS2 is an indirect bandgap semiconductor and generally optically inactive. Here we report electric-field-induced strong electroluminescence in multilayer MoS2. We show that GaN–Al2O3–MoS2 and GaN–Al2O3–MoS2–Al2O3-graphene vertical heterojunctions can be created with excellent rectification behaviour. Electroluminescence studies demonstrate prominent direct bandgap excitonic emission in multilayer MoS2 over the entire vertical junction area. Importantly, the electroluminescence efficiency observed in multilayer MoS2 is comparable to or higher than that in monolayers. This strong electroluminescence can be attributed to electric-field-induced carrier redistribution from the lowest energy points (indirect bandgap) to higher energy points (direct bandgap) in k-space. The electric-field-induced electroluminescence is general for other layered materials including WSe2 and can open up a new pathway towards transition metal dichalcogenide-based optoelectronic devices. PMID:26130491

  18. Spin motive force induced by Rashba interaction in the strong sd coupling regime

    NASA Astrophysics Data System (ADS)

    Tatara, Gen; Nakabayashi, Noriyuki; Lee, Kyun-Jin

    2013-02-01

    Spin motive force induced by the Rashba interaction in the presence of strong sd interaction between conduction electron and localized spin is theoretically studied. The motive force is calculated by evaluating the time derivative of the current density on the basis of microscopic formalism. It is shown that there are two motive forces, one proportional to ER×ṅ, the other, perpendicular component proportional to ER×(n×ṅ), where ER and n are the Rashba electric field and localized spin direction, respectively. The second type arises in the strong sd coupling regime from the spin relaxation. The appearance of perpendicular component from the spin relaxation is understood from the analogy with the current-induced torques. In the case of domain wall motion, the two contributions to the spin motive force are the same order of magnitude, while the first term dominates in the case of precession of uniform magnetization. Our result explains the appearance of the perpendicular component in the weak sd coupling limit, recently discussed in the context of spin damping monopole. Detection of ac voltage induced by the precession of uniform magnetization serves as a experimental evidence of the Rashba interaction in films and wires.

  19. Strong turbulent mixing induced by internal bores interacting with internal tide-driven vertically sheared flow

    NASA Astrophysics Data System (ADS)

    Masunaga, Eiji; Fringer, Oliver B.; Yamazaki, Hidekatsu; Amakasu, Kazuo

    2016-03-01

    We observed the formation of an internal bore interacting with the vertically sheared flow generated during the previous phase of the internal tide, which resulted in strong turbulent mixing. The rate of turbulent kinetic energy dissipation reached on the order of 10-5 W kg-1 during the event. Numerical simulations reproduced the observed interaction of internal bores with the sheared flow and verified the hypothesized breaking and mixing mechanism. The numerical results indicated that the Iribarren number, or the ratio of the topographic slope to the internal wave slope, plays a major role in the mixing intensity and types of internal bores. It was found that waves with low Iribarren numbers lead to bores that interact with vertically sheared flows induced by the previous phase of the internal tide and are more likely to produce strong wave breaking and mixing.

  20. Optically induced strong intermodal coupling in mechanical resonators at room temperature

    SciTech Connect

    Ohta, R.; Okamoto, H.; Yamaguchi, H.; Hey, R.; Friedland, K. J.

    2015-08-31

    Strong parametric mode coupling in mechanical resonators is demonstrated at room temperature by using the photothermal effect in thin membrane structures. Thanks to the large stress modulation by laser irradiation, the coupling rate of the mechanical modes, defined as half of the mode splitting, reaches 2.94 kHz, which is an order of magnitude larger than electrically induced mode coupling. This large coupling rate exceeds the damping rates of the mechanical resonators and results in the strong coupling regime, which is a signature of coherent mode interaction. Room-temperature coherent mode coupling will enable us to manipulate mechanical motion at practical operation temperatures and provides a wide variety of applications of integrated mechanical systems.

  1. Studies of HF-induced Strong Plasma Turbulence at the HAARP Ionospheric Observatory

    NASA Astrophysics Data System (ADS)

    Sheerin, J. P.; Adham, N.; Roe, R. G. E.; Keith, M. R.; Watkins, B. J.; Bristow, W. A.; Bernhardt, P. A.; Selcher, C. A.

    2010-11-01

    High power HF transmitters may induce a number of plasma instabilities in the interaction region of overdense ionospheric plasma. We report results from our recent experiments using over one gigawatt of HF power (ERP) to generate and study strong Langmuir turbulence (SLT) and particle acceleration at the HAARP Observatory, Gakona, Alaska. Among the effects observed and studied in UHF radar backscatter are: SLT spectra including the outshifted plasma line or free-mode, appearance of a short timescale ponderomotive overshoot effect, collapse, cascade and co-existing spectra, control of artificial field-aligned irregularities (AFAI), the aspect angle dependence of the plasma line spectra, and suprathermal electrons. Mapping the intensity of SLT versus pointing angle, we have discovered a number of regions of strong interaction displaced from the primary HF interaction region. Stimulated electromagnetic emission (SEE) measurements complement radar measurements. Experimental results are compared to previous high latitude experiments and predictions from recent modeling efforts.

  2. Studies of HF-induced Strong Langmuir Turbulence at the HAARP Ionospheric Observatory

    NASA Astrophysics Data System (ADS)

    Sheerin, J. P.; Gerres, J. M.; Keith, M. R.; Adham, N.; Wittbrodt, A.; Watkins, B. J.; Bristow, W. A.; Bernhardt, P. A.; Selcher, C. A.

    2009-11-01

    High power HF transmitters may induce a number of plasma instabilities in the interaction region of overdense ionospheric plasma. We report results from our recent experiments using over one gigawatt of HF power (ERP) to generate and study strong Langmuir turbulence (SLT) and particle acceleration at the HAARP Observatory, Gakona, Alaska. Among the effects observed and studied are: SLT spectra including the outshifted plasma line or free-mode, appearance of a short timescale ponderomotive overshoot effect, collapse, cascade and co-existing spectra, control of artificial field-aligned irregularities (AFAI), the aspect angle dependence of the plasma line spectra, and suprathermal electrons. Mapping the intensity of SLT versus pointing angle, we have discovered a number of regions of strong interaction displaced from the primary HF interaction region. Experimental results are compared to previous high latitude experiments and predictions from recent modeling efforts.

  3. Studies of HF-induced Strong Plasma Turbulence at the HAARP Ionospheric Observatory

    NASA Astrophysics Data System (ADS)

    Sheerin, J. P.; Adham, N.; Watanabe, N.; Watkins, B. J.; Bristow, W. A.; Selcher, C. A.; Bernhardt, P. A.

    2011-10-01

    High power HF transmitters may induce a number of plasma instabilities in the interaction region of overdense ionospheric plasma. We report results from our recent experiments using over one gigawatt of HF power (ERP) to generate and study strong Langmuir turbulence (SLT) and particle acceleration at the HAARP Observatory, Gakona, Alaska. Among the effects observed and studied in UHF radar backscatter are: SLT spectra including the outshifted plasma line or free-mode, appearance of a short timescale ponderomotive overshoot effect, collapse, cascade and co-existing spectra, control of artificial field-aligned irregularities (AFAI), the aspect angle dependence of the plasma line spectra, and suprathermal electrons. Mapping the intensity of SLT versus pointing angle, we have discovered a number of regions of strong interaction displaced from the primary HF interaction region. Stimulated electromagnetic emission (SEE) measurements complement radar measurements. Experimental results are compared to previous high latitude experiments and predictions from recent modeling efforts.

  4. Minicharged particles search by strong laser pulse-induced vacuum polarization effects

    NASA Astrophysics Data System (ADS)

    Villalba-Chávez, S.; Meuren, S.; Müller, C.

    2016-12-01

    Laser-based searches of the yet unobserved vacuum birefringence might be sensitive for very light hypothetical particles carrying a tiny fraction of the electron charge. We show that, with the help of contemporary techniques, polarimetric investigations driven by an optical laser pulse of moderate intensity might allow for excluding regions of the parameter space of these particle candidates which have not been discarded so far by laboratory measurement data. Particular attention is paid to the role of a Gaussian wave profile. It is argued that, at energy regimes in which the vacuum becomes dichroic due to these minicharges, the transmission probability of a probe beam through an analyzer set crossed to the initial polarization direction will depend on both the induced ellipticity as well as the rotation of the initial polarization plane. The weak and strong field regimes, relative to the attributes of these minicharged particles, and the relevance of the polarization of the strong field are investigated.

  5. Paramagnetic molecule induced strong antiferromagnetic exchange coupling on a magnetic tunnel junction based molecular spintronics device.

    PubMed

    Tyagi, Pawan; Baker, Collin; D'Angelo, Christopher

    2015-07-31

    This paper reports our Monte Carlo (MC) studies aiming to explain the experimentally observed paramagnetic molecule induced antiferromagnetic coupling between ferromagnetic (FM) electrodes. Recently developed magnetic tunnel junction based molecular spintronics devices (MTJMSDs) were prepared by chemically bonding the paramagnetic molecules between the FM electrodes along the tunnel junction's perimeter. These MTJMSDs exhibited molecule-induced strong antiferromagnetic coupling. We simulated the 3D atomic model analogous to the MTJMSD and studied the effect of molecule's magnetic couplings with the two FM electrodes. Simulations show that when a molecule established ferromagnetic coupling with one electrode and antiferromagnetic coupling with the other electrode, then theoretical results effectively explained the experimental findings. Our studies suggest that in order to align MTJMSDs' electrodes antiparallel to each other, the exchange coupling strength between a molecule and FM electrodes should be ∼50% of the interatomic exchange coupling for the FM electrodes.

  6. Strong nonlinear terahertz response induced by Dirac surface states in Bi2Se3 topological insulator.

    PubMed

    Giorgianni, Flavio; Chiadroni, Enrica; Rovere, Andrea; Cestelli-Guidi, Mariangela; Perucchi, Andrea; Bellaveglia, Marco; Castellano, Michele; Di Giovenale, Domenico; Di Pirro, Giampiero; Ferrario, Massimo; Pompili, Riccardo; Vaccarezza, Cristina; Villa, Fabio; Cianchi, Alessandro; Mostacci, Andrea; Petrarca, Massimo; Brahlek, Matthew; Koirala, Nikesh; Oh, Seongshik; Lupi, Stefano

    2016-04-26

    Electrons with a linear energy/momentum dispersion are called massless Dirac electrons and represent the low-energy excitations in exotic materials such as graphene and topological insulators. Dirac electrons are characterized by notable properties such as a high mobility, a tunable density and, in topological insulators, a protection against backscattering through the spin-momentum locking mechanism. All those properties make graphene and topological insulators appealing for plasmonics applications. However, Dirac electrons are expected to present also a strong nonlinear optical behaviour. This should mirror in phenomena such as electromagnetic-induced transparency and harmonic generation. Here we demonstrate that in Bi2Se3 topological insulator, an electromagnetic-induced transparency is achieved under the application of a strong terahertz electric field. This effect, concomitantly determined by harmonic generation and charge-mobility reduction, is exclusively related to the presence of Dirac electron at the surface of Bi2Se3, and opens the road towards tunable terahertz nonlinear optical devices based on topological insulator materials.

  7. Possible Superconductivity Induced by Strong Spin-Orbit Coupling in Carrier Doped Iridium Oxides Insulators

    NASA Astrophysics Data System (ADS)

    Nishiguchi, Kazutaka; Shirakawa, Tomonori; Watanabe, Hiroshi; Arita, Ryotaro; Yunoki, Seiji

    2014-03-01

    5 d transition metal oxide Sr2IrO4 and its relevant Iridium oxides have attracted much interest because of exotic properties arising from highly entangled spin and orbital degrees of freedom due to strong spin-orbit coupling (SOC). Sr2IrO4 crystalizes in the layered perovskite structure, similar to cuprates. Five 5 d electrons in Ir occupy its t2 g orbitals which are split by strong SOC, locally inducing an effective total angular momentum Jeff = 1 / 2 , analogous to a S = 1 / 2 state in cuprates. Because of the similarities to cuprates, the possibility of superconductivity (SC) in Iridium oxides has been expected theoretically once mobile carriers are introduced into the Jeff = 1 / 2 antiferromagnetic insulator. To study theoretically possible SC in carrier doped Sr2IrO4, we investigate a three-orbital Hubbard model with SOC. By solving the Eliashberg equation in the random phase approximation, we find that Jeff = 1 / 2 antiferromagnetic fluctuations favor dx2 -y2-wave SC with a mixture of singlet and triplet Cooper pairings. We will also discuss the particle-hole asymmetry of the SC induced by electron and hole doping.

  8. Strong nonlinear terahertz response induced by Dirac surface states in Bi2Se3 topological insulator

    NASA Astrophysics Data System (ADS)

    Giorgianni, Flavio; Chiadroni, Enrica; Rovere, Andrea; Cestelli-Guidi, Mariangela; Perucchi, Andrea; Bellaveglia, Marco; Castellano, Michele; di Giovenale, Domenico; di Pirro, Giampiero; Ferrario, Massimo; Pompili, Riccardo; Vaccarezza, Cristina; Villa, Fabio; Cianchi, Alessandro; Mostacci, Andrea; Petrarca, Massimo; Brahlek, Matthew; Koirala, Nikesh; Oh, Seongshik; Lupi, Stefano

    2016-04-01

    Electrons with a linear energy/momentum dispersion are called massless Dirac electrons and represent the low-energy excitations in exotic materials such as graphene and topological insulators. Dirac electrons are characterized by notable properties such as a high mobility, a tunable density and, in topological insulators, a protection against backscattering through the spin-momentum locking mechanism. All those properties make graphene and topological insulators appealing for plasmonics applications. However, Dirac electrons are expected to present also a strong nonlinear optical behaviour. This should mirror in phenomena such as electromagnetic-induced transparency and harmonic generation. Here we demonstrate that in Bi2Se3 topological insulator, an electromagnetic-induced transparency is achieved under the application of a strong terahertz electric field. This effect, concomitantly determined by harmonic generation and charge-mobility reduction, is exclusively related to the presence of Dirac electron at the surface of Bi2Se3, and opens the road towards tunable terahertz nonlinear optical devices based on topological insulator materials.

  9. Strong nonlinear terahertz response induced by Dirac surface states in Bi2Se3 topological insulator

    PubMed Central

    Giorgianni, Flavio; Chiadroni, Enrica; Rovere, Andrea; Cestelli-Guidi, Mariangela; Perucchi, Andrea; Bellaveglia, Marco; Castellano, Michele; Di Giovenale, Domenico; Di Pirro, Giampiero; Ferrario, Massimo; Pompili, Riccardo; Vaccarezza, Cristina; Villa, Fabio; Cianchi, Alessandro; Mostacci, Andrea; Petrarca, Massimo; Brahlek, Matthew; Koirala, Nikesh; Oh, Seongshik; Lupi, Stefano

    2016-01-01

    Electrons with a linear energy/momentum dispersion are called massless Dirac electrons and represent the low-energy excitations in exotic materials such as graphene and topological insulators. Dirac electrons are characterized by notable properties such as a high mobility, a tunable density and, in topological insulators, a protection against backscattering through the spin–momentum locking mechanism. All those properties make graphene and topological insulators appealing for plasmonics applications. However, Dirac electrons are expected to present also a strong nonlinear optical behaviour. This should mirror in phenomena such as electromagnetic-induced transparency and harmonic generation. Here we demonstrate that in Bi2Se3 topological insulator, an electromagnetic-induced transparency is achieved under the application of a strong terahertz electric field. This effect, concomitantly determined by harmonic generation and charge-mobility reduction, is exclusively related to the presence of Dirac electron at the surface of Bi2Se3, and opens the road towards tunable terahertz nonlinear optical devices based on topological insulator materials. PMID:27113395

  10. Scale coupling in Richtmyer-Meshkov flows induced by strong shocks

    NASA Astrophysics Data System (ADS)

    Stanic, M.; Stellingwerf, R. F.; Cassibry, J. T.; Abarzhi, S. I.

    2012-08-01

    We perform the first systematic study of the nonlinear evolution and scale coupling in Richtmyer-Meshkov (RM) flows induced by strong shocks. The smoothed particle hydrodynamics code (SPHC) is employed to ensure accurate shock capturing, interface tracking and accounting for the dissipation processes. We find that in strong-shock-driven RMI the background motion is supersonic. The amplitude of the initial perturbation strongly influences the flow evolution and the interfacial mixing that can be sub-sonic or supersonic. At late times the flow remains laminar rather than turbulent, and RM bubbles flatten and decelerate. In the fluid bulk, reverse cumulative jets appear and "hot spots" are formed—local heterogeneous microstructures with temperature substantially higher than that in the ambient. Our numerical simulations agree with the zero-order, linear, weakly nonlinear, and highly nonlinear theoretical analyses as well as with the experiments and suggest that the evolution of RMI is a multi-scale and heterogeneous process with a complicated character of scale coupling.

  11. Plasmon-induced strong interaction between chiral molecules and orbital angular momentum of light

    PubMed Central

    Wu, Tong; Wang, Rongyao; Zhang, Xiangdong

    2015-01-01

    Whether or not chiral interaction exists between the optical orbital angular momentum (OAM) and a chiral molecule remains unanswered. So far, such an interaction has not been observed experimentally. Here we present a T-matrix method to study the interaction between optical OAM and the chiral molecule in a cluster of nanoparticles. We find that strong interaction between the chiral molecule and OAM can be induced by the excitation of plasmon resonances. An experimental scheme to observe such an interaction has been proposed. Furthermore, we have found that the signal of the OAM dichroism can be either positive or negative, depending on the spatial positions of nanocomposites in the cross-sections of OAM beams. The cancellation between positive and negative signals in the spatial average can explain why the interaction has not been observed in former experiments. PMID:26656892

  12. On the possibility of inducing strong plasma convection in the divertor of MAST

    NASA Astrophysics Data System (ADS)

    Ryutov, D. D.; Helander, P.; Cohen, R. H.

    2001-10-01

    In this paper, a theory is developed to describe scrape-off layer (SOL) broadening by inducing convective cells through divertor plate biasing in a tokamak. The theory is applied to the Mega-Ampere Spherical Tokamak, where such experiments are planned in the near future. Criteria are derived for achieving strong broadening and for exciting shear-flow turbulence in the SOL, and these criteria are shown to be attainable in practice. It is also shown that the magnetic shear present in the vicinity of the X-point is likely to confine the potential perturbations to the divertor region below the X-point, leaving the part of the SOL that is in direct contact with the core plasma intact. The current created in the SOL by the biasing and the associated heating power are also calculated and are found to be modest.

  13. Developmental abnormality induced by strong static magnetic field in Caenorhabditis elegans.

    PubMed

    Wang, Lei; Du, Hua; Guo, Xiaoying; Wang, Xinan; Wang, Meimei; Wang, Yichen; Wang, Min; Chen, Shaopeng; Wu, Lijun; Xu, An

    2015-04-01

    Understanding the effects of strong static magnetic fields (SMFs) on living organisms is significant in health risk assessment, but underlying mechanisms are largely unknown. In the present study, we determined developmental abnormalities induced by 8.5Tesla (T) SMFs in a well-established in vivo model organism, Caenorhabditis elegans (C. elegans). Exposure of C. elegans eggs to 8.5 T SMF resulted in a time-dependent lifespan decrease, whereas only slight changes were observed upon exposure to 5 T SMF. Although SMF exposure did not alter brood size, development rate and stages were significantly modified by 8.5 T SMF. Germ cell apoptosis dramatically increased upon exposure to 8.5 T SMF in adult worms, as confirmed by ced-3 and ced-4 mutants, and could be prevented by concurrent treatment with a free radical scavenger, dimethyl sulfoxide. Compared to wild-type worms, shorter lifespan and greater numbers of apoptotic cells were observed in abnormal methyl viologen sensitivity-1 (mev-1(kn1)) nematodes with increased sensitivity to oxidative damage. Furthermore, exposure to 8.5 T SMF increased expression of superoxide dismutase-3 (sod-3), which is thought to protect against oxidative stress. However, 8.5 T SMF had minimal effects on lifespans of daf-2 and daf-16 mutants, which have compromised insulin/IGF-1 (insulin-like growth factors-1) mediated signaling pathways; this finding was consistent with the expression of these genes in wild-type worms. Our results indicate that developmental toxicity induced by strong SMF in C. elegans is mediated by oxidative stress and may be regulated by the insulin-like receptor pathway.

  14. Strong interface-induced spin-orbit interaction in graphene on WS2.

    PubMed

    Wang, Zhe; Ki, Dong-Keun; Chen, Hua; Berger, Helmuth; MacDonald, Allan H; Morpurgo, Alberto F

    2015-09-22

    Interfacial interactions allow the electronic properties of graphene to be modified, as recently demonstrated by the appearance of satellite Dirac cones in graphene on hexagonal boron nitride substrates. Ongoing research strives to explore interfacial interactions with other materials to engineer targeted electronic properties. Here we show that with a tungsten disulfide (WS2) substrate, the strength of the spin-orbit interaction (SOI) in graphene is very strongly enhanced. The induced SOI leads to a pronounced low-temperature weak anti-localization effect and to a spin-relaxation time two to three orders of magnitude smaller than in graphene on conventional substrates. To interpret our findings we have performed first-principle electronic structure calculations, which confirm that carriers in graphene on WS2 experience a strong SOI and allow us to extract a spin-dependent low-energy effective Hamiltonian. Our analysis shows that the use of WS2 substrates opens a possible new route to access topological states of matter in graphene-based systems.

  15. Effect of initial perturbation amplitude on Richtmyer-Meshkov flows induced by strong shocks

    NASA Astrophysics Data System (ADS)

    Dell, Zachary; Stellingwerf, Robert; Abarzhi, Snezhana

    2015-11-01

    We study the effect initial perturbation on the Richtmyer-Meshkov (RM) flows induced by strong shocks in fluids with contrasting densities. Smooth Particle Hydrodynamics simulations are employed. Broad range of shock strengths and density ratios is considered (Mach=3,5,10, and Atwood=0.6,0.8,0.95). The amplitude of initial single mode sinusoidal perturbation of the interface varies from 0% to 100% of its wavelength. We analyze the initial growth-rate of the RMI immediately after the shock passage, when the perturbation amplitude increases linearly with time. We find that the initial growth-rate of RMI is a non-monotone function of the amplitude of the initial perturbation. This restrains the amount of energy that can be deposited by the shock at the interface. The maximum value of the initial growth-rate depends strongly and the corresponding value of the initial perturbation amplitude depends only slightly on the shock strength and density ratio. The maximum value of the initial growth-rate increases with the increase of the Atwood number for a fixed Mach number, and decreases with the increase of the Mach number for a fixed Atwood number. We argue that the non-monotonicity of RMI growth-rate is a result of a combination of geometric effect and the effect of secondary shocks.

  16. Effect of initial perturbation amplitude on Richtmyer-Meshkov flows induced by strong shocks

    NASA Astrophysics Data System (ADS)

    Dell, Zachary; Stellingwerf, Robert; Abarzhi, Snezhana

    2015-11-01

    We study the effect initial perturbation on the Richtmyer-Meshkov (RM) flows induced by strong shocks in fluids with contrasting densities. Smooth Particle Hydrodynamics simulations are employed. Broad range of shock strengths and density ratios is considered (Mach=3,5,10, and Atwood=0.6,0.8,0.95). The amplitude of initial single mode sinusoidal perturbation of the interface varies from 0% to 100% of its wavelength. We analyze the initial growth-rate of the RMI immediately after the shock passage, when the perturbation amplitude increases linearly with time. We find that the initial growth-rate of RMI is a non-monotone function of the amplitude of the initial perturbation. This restrains the amount of energy that can be deposited by the shock at the interface. The maximum value of the initial growth-rate depends strongly and the corresponding value of the initial perturbation amplitude depends only slightly on the shock strength and density ratio. The maximum value of the initial growth-rate increases with the increase of the Atwood number for a fixed Mach number, and decreases with the increase of the Mach number for a fixed Atwood number. We argue that the non-monotonicity of RMI growth-rate is a result of a combination of geometric effect and the effect of secondary shocks. Support of the National Science Foundation is warmly appreciated.

  17. Radiotherapy combined with TLR7/8 activation induces strong immune responses against gastrointestinal tumors

    PubMed Central

    Tietz, Alexandra; Rahbari, Nuh N.; Bork, Ulrich; Schmidt, Thomas; Kahlert, Christoph; Haberkorn, Uwe; Tomai, Mark A.; Lipson, Kenneth E.; Carretero, Rafael; Weitz, Jürgen; Koch, Moritz; Huber, Peter E.

    2015-01-01

    In addition to local cytotoxic activity, radiotherapy may also elicit local and systemic antitumor immunity, which may be augmented by immunotherapeutic agents including Toll-like receptor (TLR) 7/8 agonists. Here, we investigated the ability of 3M-011 (854A), a TLR7/8 agonist, to boost the antigen-presenting activity of dendritic cells (DC) as an adjuvant to radiotherapy. The combined treatment induced marked local and systemic responses in subcutaneous and orthotopic mouse models of colorectal and pancreatic cancer. In vitro cytotoxicity assays as well as in vivo depletion experiments with monoclonal antibodies identified NK and CD8 T cells as the cell populations mediating the cytotoxic effects of the treatment, while in vivo depletion of CD11c+ dendritic cells (DC) in CD11c-DTR transgenic mice revealed DC as the pivotal immune hub in this setting. The specificity of the immune reaction was confirmed by ELISPOT assays. TLR7/8 agonists therefore seem to be potent adjuvants to radiotherapy, inducing strong local and profound systemic immune responses to tumor antigens released by conventional therapy. PMID:25609199

  18. Strong-mixing induced deep ocean heat uptake events in the North Atlantic.

    NASA Astrophysics Data System (ADS)

    Somavilla Cabrillo, Raquel; Gonzalez-Pola, Cesar; Schauer, Ursula; Budeus, Gedeon

    2015-04-01

    The deceleration of the upper ocean heat storage during the last decade has resulted in an active search for the 'missing heat' in the deep ocean. Modeling work has provided new insights into the role of the central Pacific Ocean on the present hiatus in global warming and the efficient transfer of heat to the deep ocean, but recent studies have highlighted also the large contribution of the North Atlantic basin to these processes, mainly based on ocean observations. The deep ocean heat uptake (below 300 m) in the North Atlantic is not confined to the subpolar gyre region but extends to mid-latitudes of the Eastern North Atlantic (ENA), requiring an additional process for its explanation other than deep convection considered until now. Here, using oceanographic in-situ data, we describe a mechanism of heat and salt injection to the deep ocean after years of warming and saltening at the surface occurred both in regions of mode (43°-48°N) and deep water (74°-76°N) formation in the ENA. The mechanism, although punctual meditated by strong winter mixing events, is between 2 and 6 times higher than the 2000-2010 ocean heat uptake at depths of mode (300-700m) and deep water (>2000m) formation, contributing significantly to the observed deep ocean heat uptake in the North Atlantic. Nutrient, hydrographic and reanalysis data indicate that the strong mixing-induced deep ocean heat uptake events at areas of mode and deep water formation in the North Atlantic are connected through the northward propagation of salty ENA mode waters triggered by the contraction of the subpolar gyre reinforced by the occurrences of blocking anomalies in the ENA. Such connection is not unique of the last decade but observed also during the 1960s. Natural climate variability seems the ultimate driver of the strong mixing-induced deep ocean heat uptake events, although the anthropogenic global warming and its forcing on the Arctic sea-ice retreat and frequency of extreme weather events could

  19. [Conformational changes of actin induced by strong or weak myosin subfragment-1 binding].

    PubMed

    Dedova, I V; Avrova, S V; Vikhoreva, N N; Vikhorev, R G; Hazlett, T L; Van der Meer, W; Dos Remedios, C G; Borovikov, Iu S

    2004-01-01

    Movements of different areas of polypeptide chains within F-actin monomers induced by S1 or pPDM-S1 binding were studied by polarized fluorimetry. Thin filaments of ghost muscle were reconstructed by adding G-actin labeled with fluorescent probes attached alternatively to different sites of actin molecule. These sites were: Cys-374 labeled with 1,5-IAEDANS, TMRIA or 5-IAF; Lys-373 labeled with NBD-Cl; Lys-113 labeled with Alexa-488; Lys-61 labeled with FITC; Gln-41 labeled with DED and Cys-10 labeled with 1,5-IAEDANS, 5-IAF or fluorescein-maleimid. In addition, we used TRITC-, FITC-falloidin and e-ADP that were located, respectively, in filament groove and interdomain cleft. The data were analysed by model-dependent and model-independent methods (see appendixes). The orientation and mobility of fluorescent probes were significantly changed when actin and myosin interacted, depending on fluorophore location and binding site of actomyosin. Strong binding of S with actin leads to 1) a decrease in the orientation of oscillators of derivatives of falloidin (TRITC-falloidin, FITC-falloidin) and actin-bound nucleotide (e-ADP); 2) an increase in the orientation of dye oscillators located in the "front' surface of the small domain (where actin is viewed in the standard orientation with subdomains 1/2 and 3/4 oriented to the right and to the left, respectively); 3) a decrease in the angles of dye oscillators located on the "back" surface of subdomain-1. In contrast, a weak binding of S1 to actin induces the opposite effects in orientation of these probes. These data suggest that during the ATP hydrolysis cycle myosin heads induce a change in actin monomer (a tilt and twisting of its small domain). Presumably, these alterations in F-actin conformation play an important role in muscle contraction.

  20. Effect of a strong, DC-induced magnetic field on circadian singing activity of the house cricket (orthoptera:gryllidae)

    SciTech Connect

    Shaw, K.C.; Bitzer, R.J.; Galliart, L.

    1995-05-01

    We investigated the effect of a strong, DC-induced electromagnetic field (EMF) on the circadian singing activity of the house cricket, Acheta domesticus (L.). Groups of 10 crickets were exposed to strong, DC-induced EMFs under two light regimes, 12:12 (L:D) h and 0:24 (L:D) h. Exposure to the strong EMF resulted in an increase in mean time per hour during which one or more crickets were singing and in number of crickets singing per hour. Correcting for phase shift during O:24 (L:D) h, the daily pattern of singing was apparently unaffected by any treatment. The greatest percentage of singing and number of crickets singing per hour occurred during actual or expected scotophase. This is the first report of an increase in insect activity during exposure to a strong DC-induced EMF.

  1. Giant Faraday rotation induced by the Berry phase in bilayer graphene under strong terahertz fields

    NASA Astrophysics Data System (ADS)

    Yang, Fan; Xu, Xiaodong; Liu, Ren-Bao

    2014-04-01

    High-order terahertz (THz) sideband generation in semiconductors is a phenomenon with physics similar to that of high-order harmonic generation but in a regime of much lower frequency. Our previous paper [1] found that the electron-hole pair excited by a weak optical laser can accumulate a Berry phase along a cyclic trajectory under the driving of a strong elliptically polarized THz field. Furthermore, the Berry phase appears as the Faraday rotation angle of the emission signal under short-pulse excitation in monolayer MoS_{2}. In this paper, the theory of the Berry phase in THz extreme nonlinear optics is applied to biased bilayer graphene with Bernal stacking, which has similar Bloch band features and optical properties to monolayer MoS_{2}, such as the time-reversal related valleys and the valley contrasting optical selection rule. However, the biased bilayer graphene has much larger Berry curvature than monolayer MoS_{2}, which leads to a large Berry phase of the quantum trajectory and in turn a giant Faraday rotation of the optical emission (˜1 rad for a THz field with frequency 1 THz and strength 8 kV cm-1). This surprisingly big angle shows that the Faraday rotation can be induced more efficiently by the Berry curvature in momentum space than by the magnetic field in real space. It provides opportunities to use bilayer graphene and THz lasers for ultrafast electro-optical devices.

  2. Interferon-β gene transfer induces a strong cytotoxic bystander effect on melanoma cells.

    PubMed

    Rossi, Úrsula A; Gil-Cardeza, María L; Villaverde, Marcela S; Finocchiaro, Liliana M E; Glikin, Gerardo C

    2015-05-01

    A local gene therapy scheme for the delivery of type I interferons could be an alternative for the treatment of melanoma. We evaluated the cytotoxic effects of interferon-β (IFNβ) gene lipofection on tumor cell lines derived from three human cutaneous and four canine mucosal melanomas. The cytotoxicity of human IFNβ gene lipofection resulted higher or equivalent to that of the corresponding addition of the recombinant protein (rhIFNβ) to human cells. IFNβ gene lipofection was not cytotoxic for only one canine melanoma cell line. When cultured as monolayers, three human and three canine IFNβ-lipofected melanoma cell lines displayed a remarkable bystander effect. As spheroids, the same six cell lines were sensitive to IFNβ gene transfer, two displaying a significant multicell resistance phenotype. The effects of conditioned IFNβ-lipofected canine melanoma cell culture media suggested the release of at least one soluble thermolabile cytotoxic factor that could not be detected in human melanoma cells. By using a secretion signal-free truncated human IFNβ, we showed that its intracellular expression was enough to induce cytotoxicity in two human melanoma cell lines. The lower cytoplasmatic levels of reactive oxygen species detected after intracellular IFNβ expression could be related to the resistance displayed by one human melanoma cell line. As IFNβ gene transfer was effective against most of the assayed melanomas in a way not limited by relatively low lipofection efficiencies, the clinical potential of this approach is strongly supported.

  3. Phase transitions in ensembles of solitons induced by an optical pumping or a strong electric field

    NASA Astrophysics Data System (ADS)

    Karpov, P.; Brazovskii, S.

    2016-09-01

    The latest trend in studies of modern electronically and/or optically active materials is to provoke phase transformations induced by high electric fields or by short (femtosecond) powerful optical pulses. The systems of choice are cooperative electronic states whose broken symmetries give rise to topological defects. For typical quasi-one-dimensional architectures, those are the microscopic solitons taking from electrons the major roles as carriers of charge or spin. Because of the long-range ordering, the solitons experience unusual super-long-range forces leading to a sequence of phase transitions in their ensembles: the higher-temperature transition of the confinement and the lower one of aggregation into macroscopic walls. Here we present results of an extensive numerical modeling for ensembles of both neutral and charged solitons in both two- and three-dimensional systems. We suggest a specific Monte Carlo algorithm preserving the number of solitons, which substantially facilitates the calculations, allows to extend them to the three-dimensional case and to include the important long-range Coulomb interactions. The results confirm the first confinement transition, except for a very strong Coulomb repulsion, and demonstrate a pattern formation at the second transition of aggregation.

  4. Mucosal vaccination with attenuated Mycobacterium tuberculosis induces strong central memory responses and protects against tuberculosis

    PubMed Central

    Kaushal, Deepak; Foreman, Taylor W.; Gautam, Uma S.; Alvarez, Xavier; Adekambi, Toidi; Rangel-Moreno, Javier; Golden, Nadia A.; Johnson, Ann-Marie F.; Phillips, Bonnie L.; Ahsan, Muhammad H.; Russell-Lodrigue, Kasi E.; Doyle, Lara A.; Roy, Chad J.; Didier, Peter J.; Blanchard, James L.; Rengarajan, Jyothi; Lackner, Andrew A.; Khader, Shabaana A.; Mehra, Smriti

    2015-01-01

    Tuberculosis (TB) is a global pandaemic, partially due to the failure of vaccination approaches. Novel anti-TB vaccines are therefore urgently required. Here we show that aerosol immunization of macaques with the Mtb mutant in SigH (MtbΔsigH) results in significant recruitment of inducible bronchus-associated lymphoid tissue (iBALT) as well as CD4+ and CD8+ T cells expressing activation and proliferation markers to the lungs. Further, the findings indicate that pulmonary vaccination with MtbΔsigH elicited strong central memory CD4+ and CD8+ T-cell responses in the lung. Vaccination with MtbΔsigH results in significant protection against a lethal TB challenge, as evidenced by an approximately three log reduction in bacterial burdens, significantly diminished clinical manifestations and granulomatous pathology and characterized by the presence of profound iBALT. This highly protective response is virtually absent in unvaccinated and BCG-vaccinated animals after challenge. These results suggest that future TB vaccine candidates can be developed on the basis of MtbΔsigH. PMID:26460802

  5. Effect of initial perturbation amplitude on Richtmyer-Meshkov flows induced by strong shocks

    SciTech Connect

    Dell, Z.; Abarzhi, S. I. E-mail: sabarji@andrew.cmu.edu; Stellingwerf, R. F.

    2015-09-15

    We systematically study the effect of the initial perturbation on Richtmyer-Meshkov (RM) flows induced by strong shocks in fluids with contrasting densities. Smooth Particle Hydrodynamics simulations are employed. A broad range of shock strengths and density ratios is considered. The amplitude of the initial single mode sinusoidal perturbation of the interface varies from 0% to 100% of its wavelength. The simulations results are compared, wherever possible, with four rigorous theories, and with other experiments and simulations, achieving good quantitative and qualitative agreement. Our study is focused on early time dynamics of the Richtmyer-Meshkov instability (RMI). We analyze the initial growth-rate of RMI immediately after the shock passage, when the perturbation amplitude increases linearly with time. For the first time, to the authors' knowledge, we find that the initial growth-rate of RMI is a non-monotone function of the initial perturbation amplitude, thus restraining the amount of energy that can be deposited by the shock at the interface. The maximum value of the initial growth-rate depends on the shock strength and the density ratio, whereas the corresponding value of the initial perturbation amplitude depends only slightly on the shock strength and density ratio.

  6. Large mixing induced by the strong coupling with a single bulk neutrino

    NASA Astrophysics Data System (ADS)

    Lam, C. S.

    2002-03-01

    The neutrino is a good probe of extra dimensions. Large mixing and the apparent lack of very complicated oscillation patterns may be an indication of large couplings between the brane and a single bulk neutrino. A simple and realistic five-dimensional model of this kind is discussed. It requires a sterile neutrino in addition to three active neutrinos on the brane, all coupled strongly to one common bulk neutrino, but not directly among themselves. Mindful that sterile neutrinos are disfavored in the atmospheric and solar data, we demand induced mixing to occur among the active neutrinos, but not between the active and the sterile. The size R of the extra dimension is arbitrary in this model, otherwise it contains six parameters which can be used to fit the three neutrino masses and the three mixing angles. However, in the model these six parameters must be suitably ordered, so a successful fit is not guaranteed. It turns out that not only can the data be fitted, but, as a result of the ordering, a natural connection between the smallness of the reactor angle θ13 and the smallness of the mass-gap ratio ΔM2solar/ΔM2atmospheric can be derived.

  7. Titanium dioxide nanoparticles induce strong oxidative stress and mitochondrial damage in glial cells.

    PubMed

    Huerta-García, Elizabeth; Pérez-Arizti, José Antonio; Márquez-Ramírez, Sandra Gissela; Delgado-Buenrostro, Norma Laura; Chirino, Yolanda Irasema; Iglesias, Gisela Gutiérrez; López-Marure, Rebeca

    2014-08-01

    Titanium dioxide nanoparticles (TiO2 NPs) are widely used in the chemical, electrical, and electronic industries. TiO2 NPs can enter directly into the brain through the olfactory bulb and can be deposited in the hippocampus region; therefore, we determined the toxic effect of TiO2 NPs on rat and human glial cells, C6 and U373, respectively. We evaluated some events related to oxidative stress: (1) redox-signaling mechanisms by oxidation of 2',7'-dichlorodihydrofluorescein diacetate; (2) peroxidation of lipids by cis-parinaric acid; (3) antioxidant enzyme expression by PCR in real time; and (4) mitochondrial damage by MitoTracker Green FM staining and Rh123. TiO2 NPs induced a strong oxidative stress in both glial cell lines by mediating changes in the cellular redox state and lipid peroxidation associated with a rise in the expression of glutathione peroxidase, catalase, and superoxide dismutase 2. TiO2 NPs also produced morphological changes, damage of mitochondria, and an increase in mitochondrial membrane potential, indicating toxicity. TiO2 NPs had a cytotoxic effect on glial cells; however, more in vitro and in vivo studies are required to ascertain that exposure to TiO2 NPs can cause brain injury and be hazardous to health.

  8. Platelet lysate induces in vitro wound healing of human keratinocytes associated with a strong proinflammatory response.

    PubMed

    El Backly, Rania; Ulivi, Valentina; Tonachini, Laura; Cancedda, Ranieri; Descalzi, Fiorella; Mastrogiacomo, Maddalena

    2011-07-01

    Platelet lysates (PL), which are derived from platelets, are cocktails of growth factors and cytokines that can promote tissue regeneration. Until today, most studies have focused on growth factor content of platelets rather than on their potential as a reservoir of mediators and cytokines. Taking advantage of an in vitro scratch assay performed under both normal and inflammatory conditions, in the present work, we report that at physiologic concentrations, PL enhanced wound closure rates of NCTC 2544 human keratinocytes. This effect was clearly detectable 6 h after wounding. Moreover, PL induced a strong cell actin cytoskeletal re-organization that persisted up to 24 h. The accelerated wound closure promoted by PL, in either presence or absence of serum, was associated with a high expression of the inflammatory cytokine interleukin-8. Further, after 24 h PL treatment, confluent keratinocytes also expressed low amounts of interleukin-8 and of the antimicrobial peptide neutrophil gelatinase-associated lipocalin, which dramatically increased under inflammatory conditions. These effects were associated with activation of the inflammatory pathways, p38 mitogen-activated protein kinase, and NF-κB. Our findings support the concept that platelet-derived preparations could accelerate regeneration of difficult-to-heal wounds by triggering an inflammatory cascade and having an antimicrobial role.

  9. Vv-AMP1, a ripening induced peptide from Vitis vinifera shows strong antifungal activity

    PubMed Central

    de Beer, Abré; Vivier, Melané A

    2008-01-01

    Background Latest research shows that small antimicrobial peptides play a role in the innate defense system of plants. These peptides typically contribute to preformed defense by developing protective barriers around germinating seeds or between different tissue layers within plant organs. The encoding genes could also be upregulated by abiotic and biotic stimuli during active defense processes. The peptides display a broad spectrum of antimicrobial activities. Their potent anti-pathogenic characteristics have ensured that they are promising targets in the medical and agricultural biotechnology sectors. Results A berry specific cDNA sequence designated Vv-AMP1, Vitis vinifera antimicrobial peptide 1, was isolated from Vitis vinifera. Vv-AMP1 encodes for a 77 amino acid peptide that shows sequence homology to the family of plant defensins. Vv-AMP1 is expressed in a tissue specific, developmentally regulated manner, being only expressed in berry tissue at the onset of berry ripening and onwards. Treatment of leaf and berry tissue with biotic or abiotic factors did not lead to increased expression of Vv-AMP1 under the conditions tested. The predicted signal peptide of Vv-AMP1, fused to the green fluorescent protein (GFP), showed that the signal peptide allowed accumulation of its product in the apoplast. Vv-AMP1 peptide, produced in Escherichia coli, had a molecular mass of 5.495 kDa as determined by mass spectrometry. Recombinant Vv-AMP1 was extremely heat-stable and showed strong antifungal activity against a broad spectrum of plant pathogenic fungi, with very high levels of activity against the wilting disease causing pathogens Fusarium oxysporum and Verticillium dahliae. The Vv-AMP1 peptide did not induce morphological changes on the treated fungal hyphae, but instead strongly inhibited hyphal elongation. A propidium iodide uptake assay suggested that the inhibitory activity of Vv-AMP1 might be associated with altering the membrane permeability of the fungal

  10. Two-dimensional metal-insulator transition as a strong localization induced crossover phenomenon

    NASA Astrophysics Data System (ADS)

    Das Sarma, S.; Hwang, E. H.

    2014-06-01

    Low-disorder and high-mobility two-dimensional (2D) electron (or hole) systems confined in semiconductor heterostructures undergo an apparent metal-insulator transition (MIT) at low temperatures as the carrier density (n) is varied. In some situations, the 2D MIT can be caused at a fixed low carrier density by changing an externally applied in-plane magnetic field parallel to the 2D layer. The goal of the current work is to obtain the critical density (nc) for the 2D MIT with the system being an effective metal (Anderson insulator) for density n above (below) nc. We study the 2D MIT phenomenon theoretically as a possible strong localization induced crossover process controlled by the Ioffe-Regel criterion, kFl=1, where kF(n) is the 2D Fermi wave vector and l (n) is the disorder-limited quantum mean free path on the metallic side. Calculating the quantum mean free path in the effective metallic phase from a realistic Boltzmann transport theory including disorder scattering effects, we solve the integral equation (with l depending on n through multidimensional integrals) defined by the Ioffe-Regel criterion to obtain the nonuniversal critical density nc as a function of the applicable physical experimental parameters including disorder strength, in-plane magnetic field, spin and valley degeneracy, background dielectric constant and carrier effective mass, and temperature. The key physics underlying the nonuniversal parameter dependence of the critical density is the density dependence of the screened Coulomb disorder. Our calculated results for the crossover critical density nc appear to be in qualitative and semiquantitative agreement with the available experimental data in different 2D semiconductor systems lending credence to the possibility that the apparent 2D MIT signals the onset of the strong localization crossover in disordered 2D systems. We also compare the calculated critical density obtained from the Ioffe-Regel criterion with that obtained from a

  11. Interfaces between strongly correlated oxides: controlling charge transfer and induced magnetism by hybridization

    NASA Astrophysics Data System (ADS)

    Bibes, Manuel

    At interfaces between conventional materials, band bending and alignment are controlled by differences in electrochemical potential. Applying this concept to oxides in which interfaces can be polar and cations may adopt a mixed valence has led to the discovery of novel two-dimensional states between simple band insulators such as LaAlO3 and SrTiO3. However, many oxides have a more complex electronic structure, with charge, orbital and/or spin orders arising from correlations between transition metal and oxygen ions. Strong correlations thus offer a rich playground to engineer functional interfaces but their compatibility with the classical band alignment picture remains an open question. In this talk we will show that beyond differences in electron affinities and polar effects, a key parameter determining charge transfer at correlated oxide interfaces is the energy required to alter the covalence of the metal-oxygen bond. Using the perovskite nickelate (RNiO3) family as a template, we have probed charge reconstruction at interfaces with gadolinium titanate GdTiO3 using soft X-ray absorption spectroscopy and hard X-ray photoemission spectroscopy. We show that the charge transfer is thwarted by hybridization effects tuned by the rare-earth (R) size. Charge transfer results in an induced ferromagnetic-like state in the nickelate (observed by XMCD), exemplifying the potential of correlated interfaces to design novel phases. Further, our work clarifies strategies to engineer two-dimensional systems through the control of both doping and covalence. Work supported by ERC CoG MINT #615759.

  12. Advanced In vivo Use of CRISPR/Cas9 and Anti-sense DNA Inhibition for Gene Manipulation in the Brain

    PubMed Central

    Walters, Brandon J.; Azam, Amber B.; Gillon, Colleen J.; Josselyn, Sheena A.; Zovkic, Iva B.

    2016-01-01

    Gene editing tools are essential for uncovering how genes mediate normal brain–behavior relationships and contribute to neurodegenerative and neuropsychiatric disorders. Recent progress in gene editing technology now allows neuroscientists unprecedented access to edit the genome efficiently. Although many important tools have been developed, here we focus on approaches that allow for rapid gene editing in the adult nervous system, particularly CRISPR/Cas9 and anti-sense nucleotide-based techniques. CRISPR/Cas9 is a flexible gene editing tool, allowing the genome to be manipulated in diverse ways. For instance, CRISPR/Cas9 has been successfully used to knockout genes, knock-in mutations, overexpress or inhibit gene activity, and provide scaffolding for recruiting specific epigenetic regulators to individual genes and gene regions. Moreover, the CRISPR/Cas9 system may be modified to target multiple genes at one time, affording simultaneous inhibition and overexpression of distinct genetic targets. Although many of the more advanced applications of CRISPR/Cas9 have not been applied to the nervous system, the toolbox is widely accessible, such that it is poised to help advance neuroscience. Anti-sense nucleotide-based technologies can be used to rapidly knockdown genes in the brain. The main advantage of anti-sense based tools is their simplicity, allowing for rapid gene delivery with minimal technical expertise. Here, we describe the main applications and functions of each of these systems with an emphasis on their many potential applications in neuroscience laboratories. PMID:26793235

  13. Widespread anti-sense transcription in apple is correlated with siRNA production and indicates a large potential for transcriptional and/or post-transcriptional control.

    PubMed

    Celton, Jean-Marc; Gaillard, Sylvain; Bruneau, Maryline; Pelletier, Sandra; Aubourg, Sébastien; Martin-Magniette, Marie-Laure; Navarro, Lionel; Laurens, François; Renou, Jean-Pierre

    2014-07-01

    Characterizing the transcriptome of eukaryotic organisms is essential for studying gene regulation and its impact on phenotype. The realization that anti-sense (AS) and noncoding RNA transcription is pervasive in many genomes has emphasized our limited understanding of gene transcription and post-transcriptional regulation. Numerous mechanisms including convergent transcription, anti-correlated expression of sense and AS transcripts, and RNAi remain ill-defined. Here, we have combined microarray analysis and high-throughput sequencing of small RNAs (sRNAs) to unravel the complexity of transcriptional and potential post-transcriptional regulation in eight organs of apple (Malus × domestica). The percentage of AS transcript expression is higher than that identified in annual plants such as rice and Arabidopsis thaliana. Furthermore, we show that a majority of AS transcripts are transcribed beyond 3'UTR regions, and may cover a significant portion of the predicted sense transcripts. Finally we demonstrate at a genome-wide scale that anti-sense transcript expression is correlated with the presence of both short (21-23 nt) and long (> 30 nt) siRNAs, and that the sRNA coverage depth varies with the level of AS transcript expression. Our study provides a new insight on the functional role of anti-sense transcripts at the genome-wide level, and a new basis for the understanding of sRNA biogenesis in plants.

  14. Coexistence of sense and anti-sense mRNAs of variant surface protein in Giardia lamblia trophozoites.

    PubMed

    Guo, Junli; Zheng, Wenyu; Wang, Yuehua; Li, Yao; Lu, Siqi; Feng, Xianmin

    2014-02-14

    A strategy of the parasitic protozoan Giardia lamblia to evade attack from the host immune system is periodic changes of its surface antigen, a member of the variant surface protein (VSP) family. A post-transcriptional gene silencing mechanism has been proposed to explain the presence of only one among many possible VSPs at any time. To investigate this phenomenon further, we extracted total RNA from cultured trophozoites of the G. lamblia C2 isolate, and cDNA was reverse-transcribed from the RNA. Sense and anti-sense VSPs were amplified from the total cDNA using nested PCR with primers designed from the 3'-conserved region and the known 5' or 3' end of the cDNA library. Sequence analyses of the amplified products revealed more than 34 full-length antisense VSPs and a smear of sense VSPs. Sequence alignments and comparisons revealed that these VSPs contained variable N-termini and conserved C-termini, and could be classified into 5 clades based on the sizes and variations of the N-terminal sequence. All antisense VSPs existed in the sense forms, but no corresponding antisense VSP existed for sense RNA (snsRNA) 16. The coexistence of sense and antisense VSP mRNAs in cultured G. lamblia supports the post-transcriptional regulation of VSP expression. We propose that VSPs transcribed simultaneously in the sense and antisense forms form double-stranded RNAs (dsRNAs) which are degraded by the Dicer endonuclease, while a VSP without an antisense transcription (e.g., snsRNA16) will be expressed on the surface of Giardia. In addition, in the course of this investigation VSPs were identified that were previously not known. PCR-based amplification of specific sense and antisense VSP cDNAs can be used to identify the specific VSP on G. lamblia trophozoites, which is easier than using specific monoclonal antibody approaches.

  15. CpG oligodeoxynucleotides induce strong up-regulation of interleukin 33 via Toll-like receptor 9.

    PubMed

    Shimosato, Takeshi; Fujimoto, Megumi; Tohno, Masanori; Sato, Takashi; Tateo, Mariko; Otani, Hajime; Kitazawa, Haruki

    2010-03-26

    We previously reported the strong immunostimulatory effects of a CpG oligodeoxynucleotide (ODN), designated MsST, from the lacZ gene of Streptococcus (S.) thermophilus ATCC19258. Here we show that 24h of stimulation with MsST in mouse splenocytes and peritoneal macrophages strongly induces expression of interleukin (IL)-33, a cytokine in the IL-1 superfamily. Other IL-1 superfamily members, including IL-1alpha, IL-1beta and IL-18, are down-regulated after 24h of stimulation of MsST. We also found that MsST-induced IL-33 mRNA expression is inhibited by the suppressive ODN A151, which can inhibit Toll-like receptor 9 (TLR9)-mediated responses. This is the first report to show that IL-33 can be induced by CpG ODNs. The strong induction of IL-33 by MsST suggests that it may be a potential therapeutic ODN for the treatment of inflammatory disease. The presence of a strong CpG ODN in S. thermophilus also suggests that the bacterium may be a good candidate as a starter culture for the development of new physiologically functional foods.

  16. New mechanism of kinetic exchange interaction induced by strong magnetic anisotropy

    PubMed Central

    Iwahara, Naoya; Chibotaru, Liviu F.

    2016-01-01

    It is well known that the kinetic exchange interaction between single-occupied magnetic orbitals (s-s) is always antiferromagnetic, while between single- and double-occupied orbitals (s-d) is always ferromagnetic and much weaker. Here we show that the exchange interaction between strongly anisotropic doublets of lanthanides, actinides and transition metal ions with unquenched orbital momentum contains a new s-d kinetic contribution equal in strength with the s-s one. In non-collinear magnetic systems, this s-d kinetic mechanism can cause an overall ferromagnetic exchange interaction which can become very strong for transition metal ions. These findings are fully confirmed by DFT based analysis of exchange interaction in several Ln3+ complexes. PMID:27098292

  17. Sulfur Doping Induces Strong Ferromagnetic Ordering in Graphene: Effect of Concentration and Substitution Mechanism.

    PubMed

    Tuček, Jiří; Błoński, Piotr; Sofer, Zdeněk; Šimek, Petr; Petr, Martin; Pumera, Martin; Otyepka, Michal; Zbořil, Radek

    2016-07-01

    Imprinting ferromagnetism to a graphene structure by substitution of carbon atoms with sulfur is reported. S-doped graphene (4.2 at%) shows strong ferromagnetic properties with saturation magnetization exceeding 5.5 emu g(-1) at 2 K, which is among the highest values reported for any sp-based system. The remarkable magnetic response is attributed to delocalization of electrons from sulfur injected into the graphene conduction band.

  18. An antibody blocking activin type II receptors induces strong skeletal muscle hypertrophy and protects from atrophy.

    PubMed

    Lach-Trifilieff, Estelle; Minetti, Giulia C; Sheppard, KellyAnn; Ibebunjo, Chikwendu; Feige, Jerome N; Hartmann, Steffen; Brachat, Sophie; Rivet, Helene; Koelbing, Claudia; Morvan, Frederic; Hatakeyama, Shinji; Glass, David J

    2014-02-01

    The myostatin/activin type II receptor (ActRII) pathway has been identified to be critical in regulating skeletal muscle size. Several other ligands, including GDF11 and the activins, signal through this pathway, suggesting that the ActRII receptors are major regulatory nodes in the regulation of muscle mass. We have developed a novel, human anti-ActRII antibody (bimagrumab, or BYM338) to prevent binding of ligands to the receptors and thus inhibit downstream signaling. BYM338 enhances differentiation of primary human skeletal myoblasts and counteracts the inhibition of differentiation induced by myostatin or activin A. BYM338 prevents myostatin- or activin A-induced atrophy through inhibition of Smad2/3 phosphorylation, thus sparing the myosin heavy chain from degradation. BYM338 dramatically increases skeletal muscle mass in mice, beyond sole inhibition of myostatin, detected by comparing the antibody with a myostatin inhibitor. A mouse version of the antibody induces enhanced muscle hypertrophy in myostatin mutant mice, further confirming a beneficial effect on muscle growth beyond myostatin inhibition alone through blockade of ActRII ligands. BYM338 protects muscles from glucocorticoid-induced atrophy and weakness via prevention of muscle and tetanic force losses. These data highlight the compelling therapeutic potential of BYM338 for the treatment of skeletal muscle atrophy and weakness in multiple settings.

  19. Distribution of plasma and magnetic field in the Venus induced magnetosphere is strongly asymmetrical

    NASA Astrophysics Data System (ADS)

    Dubinin, E.; Fraenz, M.; Zhang, T.-L.; Woch, J.; Wei, Y.; Fedorov, A.; Barabash, S.; Lundin, R.

    2013-09-01

    Venus Express spacecraft have provided us a wealth of in-situ observations of characteristics of induced magnetosphere of Venus. One of its important features is a distinct asymmetry in plasma and field characteristics between the hemisphere pointed in the direction of the motional electric field and the opposite hemisphere. Asymmetry starts from formation of the magnetic barrier, then continues to low altitudes where effects of finite conductivity become important and further to the near Venus tail where the magnetic tail and plasma sheet are formed. As a result, the structure and dynamics of the induced magnetosphere in both hemispheres occur different. We present different aspects of such an asymmetry and discuss possible mechanisms of its appearance.

  20. Distribution of plasma and magnetic field in the Venus induced magnetosphere is strongly asymmetrical

    NASA Astrophysics Data System (ADS)

    Dubinin, E.; Fraenz, M.; Zhang, T.; Woch, J. G.; Wei, Y.; Fedorov, A.; Barabash, S. V.; Lundin, R. N.

    2013-12-01

    Venus Express spacecraft have provided us a wealth of in-situ observations of characteristics of induced magnetosphere of Venus. One of its important features is a distinct asymmetry in plasma and field characteristics between the hemisphere pointed in the direction of the motional electric field and the opposite hemisphere. Asymmetry starts from formation of the magnetic barrier, then continues to low altitudes where effects of finite conductivity become important and further to the near Venus tail where the magnetic tail and plasma sheet are formed. As a result, the structure and dynamics of the induced magnetosphere in both hemispheres occur different. We present different aspects of such an asymmetry and discuss possible mechanisms of its appearance.

  1. Enhanced turbulent mixing induced by strong wind on the South China Sea shelf

    NASA Astrophysics Data System (ADS)

    Zhang, Yanwei; Tian, Jiwei

    2014-06-01

    Integrated observations were made on the South China Sea shelf at 19°37' N, 112°04' E, under strong wind and heavy raining weather conditions in August 2005. Current data were obtained using a moored 150-kHz Acoustic Doppler Current Profiler, turbulent kinetic energy dissipation rate were measured with TurboMapII, and temperature was recorded by thermistor chains. Both the mixed layer thickness and the corresponding mean dissipation rate increased after the strong wind bursts. Average surface mixed layer thickness was 13.4 m pre-wind and 22.4 m post-wind, and the average turbulent dissipation rate in the mixed layer pre-wind and post-wind were 4.26 × 10-7 and 1.09 × 10-6 Wkg-1, respectively. The post-wind dissipation rate was 2.5 times larger than the pre-wind dissipation rate in the interior layer and four times larger in the intermediate water column. Spectra and vertical mode analysis revealed that near-inertial motion post-wind, especially with high modes, was strengthened and propagated downward toward the intermediate layer. The downward group velocity of near-inertial current was about 8.1 × 10-5 ms-1 during the strong wind bursts. The mean percentage of wind work transmitted into the intermediate layer is about 4.2 %. The ratio of post-wind high-mode energy to total horizontal kinetic energy increased below the surface mixed layer, which would have caused instabilities and result in turbulent mixing. Based on these data, we discuss a previous parameterization that relates dissipation rate, stratification, and shear variance calculated from baroclinic currents with high modes (higher than mode 1) which concentrate a large fraction of energy.

  2. Strong Field-Induced Frequency Conversion of Laser Radiation in Plasma Plumes: Recent Achievements

    PubMed Central

    Ganeev, R. A.

    2013-01-01

    New findings in plasma harmonics studies using strong laser fields are reviewed. We discuss recent achievements in the growth of the efficiency of coherent extreme ultraviolet (XUV) radiation sources based on frequency conversion of the ultrashort pulses in the laser-produced plasmas, which allowed for the spectral and structural studies of matter through the high-order harmonic generation (HHG) spectroscopy. These studies showed that plasma HHG can open new opportunities in many unexpected areas of laser-matter interaction. Besides being considered as an alternative method for generation of coherent XUV radiation, it can be used as a powerful tool for various spectroscopic and analytical applications. PMID:23864818

  3. Model simulations of strong atmospheric conductivity disturbances and induced responses of the Global Electric Circuit

    NASA Astrophysics Data System (ADS)

    Baumgaertner, A. J.; Lehto, E.; Neely, R. R.; English, J. M.; Zhu, Y.; Lucas, G.; Thayer, J. P.

    2013-12-01

    Electrical conductivity in the troposphere and stratosphere is an important quantity that determines the distribution of currents in the GEC (Global Electric Circuit), as well as the potential difference between the Earth and the ionosphere. Recently, progress in modeling atmospheric conductivity has been achieved by integrating the conductivity calculation into an AC-GCM (atmospheric chemistry general circulation model), which provides all relevant data. In this study, WACCM (Whole Atmosphere Community Climate Model) is used for conductivity calculations and an analysis of the effects of strong disturbances on the GEC. This includes volcanic eruptions of Pinatubo in 1991 and the super volcano Toba, polar stratospheric clouds, radioactive releases, and the recent strong galactic cosmic ray maximum. In general, there is a decrease in conductivity from enhanced aerosol number densities, resulting from volcanic eruptions or polar stratospheric clouds. Conductivity is increased by additional ionization sources such as radioactive releases, or galactic cosmic ray increases such as during the last solar minimum. The effects of such events on conductivity, column and total resistance, and estimate effects on current distribution and the earth-ionosphere potential difference will be quantified. Percentage change in conductivity at 20 km altitude two months after the Toba volcanic eruption (WACCM model simulation). The enhanced aerosol concentrations lead to a "conductivity hole" between 30°S and 45° N.

  4. Strong cooperative coupling of pressure-induced magnetic order and nematicity in FeSe

    SciTech Connect

    Kothapalli, K.; Bohmer, A. E.; Jayasekara, W. T.; Ueland, B. G.; Das, P.; Sapkota, A.; Taufour, V.; Xiao, Y.; Alp, E.; Bud’ko, S. L.; Canfield, P. C.; Kreyssig, A.; Goldman, A. I.

    2016-09-01

    A hallmark of the iron-based superconductors is the strong coupling between magnetic, structural and electronic degrees of freedom. However, a universal picture of the normal state properties of these compounds has been confounded by recent investigations of FeSe where the nematic (structural) and magnetic transitions appear to be decoupled. Here, using synchrotron-based high-energy x-ray diffraction and time-domain Mossbauer spectroscopy, we show that nematicity and magnetism in FeSe under applied pressure are indeed strongly coupled. Distinct structural and magnetic transitions are observed for pressures between 1.0 and 1.7 GPa and merge into a single first-order transition for pressures ≳1.7 GPa, reminiscent of what has been found for the evolution of these transitions in the prototypical system Ba(Fe1–xCox)2As2. Lastly, our results are consistent with a spin-driven mechanism for nematic order in FeSe and provide an important step towards a universal description of the normal state properties of the iron-based superconductors.

  5. Strong cooperative coupling of pressure-induced magnetic order and nematicity in FeSe

    DOE PAGES

    Kothapalli, K.; Bohmer, A. E.; Jayasekara, W. T.; ...

    2016-09-01

    A hallmark of the iron-based superconductors is the strong coupling between magnetic, structural and electronic degrees of freedom. However, a universal picture of the normal state properties of these compounds has been confounded by recent investigations of FeSe where the nematic (structural) and magnetic transitions appear to be decoupled. Here, using synchrotron-based high-energy x-ray diffraction and time-domain Mossbauer spectroscopy, we show that nematicity and magnetism in FeSe under applied pressure are indeed strongly coupled. Distinct structural and magnetic transitions are observed for pressures between 1.0 and 1.7 GPa and merge into a single first-order transition for pressures ≳1.7 GPa, reminiscentmore » of what has been found for the evolution of these transitions in the prototypical system Ba(Fe1–xCox)2As2. Lastly, our results are consistent with a spin-driven mechanism for nematic order in FeSe and provide an important step towards a universal description of the normal state properties of the iron-based superconductors.« less

  6. Strong cooperative coupling of pressure-induced magnetic order and nematicity in FeSe

    NASA Astrophysics Data System (ADS)

    Kothapalli, K.; Böhmer, A. E.; Jayasekara, W. T.; Ueland, B. G.; Das, P.; Sapkota, A.; Taufour, V.; Xiao, Y.; Alp, E.; Bud'Ko, S. L.; Canfield, P. C.; Kreyssig, A.; Goldman, A. I.

    2016-09-01

    A hallmark of the iron-based superconductors is the strong coupling between magnetic, structural and electronic degrees of freedom. However, a universal picture of the normal state properties of these compounds has been confounded by recent investigations of FeSe where the nematic (structural) and magnetic transitions appear to be decoupled. Here, using synchrotron-based high-energy x-ray diffraction and time-domain Mössbauer spectroscopy, we show that nematicity and magnetism in FeSe under applied pressure are indeed strongly coupled. Distinct structural and magnetic transitions are observed for pressures between 1.0 and 1.7 GPa and merge into a single first-order transition for pressures >~1.7 GPa, reminiscent of what has been found for the evolution of these transitions in the prototypical system Ba(Fe1-xCox)2As2. Our results are consistent with a spin-driven mechanism for nematic order in FeSe and provide an important step towards a universal description of the normal state properties of the iron-based superconductors.

  7. Strong cooperative coupling of pressure-induced magnetic order and nematicity in FeSe

    PubMed Central

    Kothapalli, K.; Böhmer, A. E.; Jayasekara, W. T.; Ueland, B. G.; Das, P.; Sapkota, A.; Taufour, V.; Xiao, Y.; Alp, E.; Bud'ko, S. L.; Canfield, P. C.; Kreyssig, A.; Goldman, A. I.

    2016-01-01

    A hallmark of the iron-based superconductors is the strong coupling between magnetic, structural and electronic degrees of freedom. However, a universal picture of the normal state properties of these compounds has been confounded by recent investigations of FeSe where the nematic (structural) and magnetic transitions appear to be decoupled. Here, using synchrotron-based high-energy x-ray diffraction and time-domain Mössbauer spectroscopy, we show that nematicity and magnetism in FeSe under applied pressure are indeed strongly coupled. Distinct structural and magnetic transitions are observed for pressures between 1.0 and 1.7 GPa and merge into a single first-order transition for pressures ≳1.7 GPa, reminiscent of what has been found for the evolution of these transitions in the prototypical system Ba(Fe1−xCox)2As2. Our results are consistent with a spin-driven mechanism for nematic order in FeSe and provide an important step towards a universal description of the normal state properties of the iron-based superconductors. PMID:27582003

  8. Counterion-induced entropic interactions in solutions of strongly stretched, osmotic polyelectrolyte stars

    NASA Astrophysics Data System (ADS)

    Jusufi, A.; Likos, C. N.; Lowen, H.

    2002-06-01

    We examine the conformations and effective interactions of star-branched polyelectrolytes with and without added salt, by employing monomer-resolved molecular dynamics simulations and an analytical theory. The simulations take into account the excluded-volume and Coulomb interactions between the individual monomers, as well as the counter- and coions. The theory is based on a variational free energy that is written as a sum of electrostatic, polymer, and entropic contributions of the counter- and coions. For the conformations of isolated polyelectrolyte stars, we find strong stretching of the chains, resulting in a linear scaling of the star radius with the degree of polymerization, as well as trapping and condensation of a large fraction of counterions. The effective interactions at arbitrarily strong overlaps between the stars are shown to be dominated by the entropic contributions of the trapped counterions, with the electrostatic contribution playing only a minor role due to an almost complete neutralization of the stars. In the case of added salt, we find a shrinking of the star size as well as a weakening of the effective force due to a generalized depletion mechanism. The good agreement between theory and simulations allows us to put forward analytic expressions for the effective interaction between polyelectrolyte stars at arbitrary separations.

  9. Phase-transition oscillations induced by a strongly focused laser beam

    NASA Astrophysics Data System (ADS)

    Devailly, Clémence; Crauste-Thibierge, Caroline; Petrosyan, Artyom; Ciliberto, Sergio

    2015-11-01

    We report the observation of a surprising phenomenon consisting in a oscillating phase transition which appears in a binary mixture when this is enlightened by a strongly focused infrared laser beam. The mixture is poly-methyl-meth-acrylate (PMMA)-3-octanone, which has an upper critical solution temperature at Tc=306.6 K and volume fraction ϕc=12.8 % [Crauste et al., arXiv:1310.6720, 2013]. We describe the dynamical properties of the oscillations, which are produced by a competition between various effects: the local accumulation of PMMA produced by the laser beam, thermophoresis, and nonlinear diffusion. We show that the main properties of this kind of oscillations can be reproduced in the Landau theory for a binary mixture in which a local driving mechanism, simulating the laser beam, is introduced.

  10. Magnetic field induced by strong transverse plasmons in ultra-relativistic electron-positron plasmas

    NASA Astrophysics Data System (ADS)

    Liu, Y.; Li, X. Q.; Liu, S. Q.

    2012-08-01

    Context. We investigated the generation of localized magnetic fields in an ultra-relativistic non-isothermal electron-positron plasma by strong electromagnetic plasmons. Aims: The results obtained can be used to explain the origin of small-scale magnetic fields in the internal shock region of gamma-ray bursts with ultra-relativistic electron positron plasmas. Methods: The generation of magnetic fields was investigated with kinetic Vlasov Maxwell equations. Results: The self-generated magnetic field will collapse for modulation instability, leading to spatially highly intermittent magnetic fluxes, whose characteristic scale is much larger than relativistic plasma skin depth, which in turn is conducive to the generation of the long-life small-scale magnetic fields in the internal shock region of gamma-ray bursts.

  11. Vacuum Particle-Antiparticle Creation in Strong Fields as a Field-Induced Phase Transition

    NASA Astrophysics Data System (ADS)

    Smolyansky, S. A.; Panferov, A. D.; Blaschke, D. B.; Juchnowski, L.; Kämpfer, B.; Otto, A.

    2017-03-01

    We study the special features of vacuum particle creation in an external classical field for two simple external field models in standard QED. Our investigation is based on a kinetic equation that is a nonperturbative consequence of the fundamental QED equations of motion. We identify the special features of system evolution that apply qualitatively also for other systems and are therefore rather general. The common basis for a description of these systems is formed by kinetic equations for vacuum particle creation belonging to the class of integro-differential equations of non-Markovian type with fastly oscillating kernel. This allows us to characterize the processes of this type as belonging to the class of field-induced phase transitions. Examples range from condensed matter physics to cosmology.

  12. Bone morphogenetic protein-4 strongly potentiates growth factor-induced proliferation of mammary epithelial cells

    SciTech Connect

    Montesano, Roberto Sarkoezi, Rita; Schramek, Herbert

    2008-09-12

    Bone morphogenetic proteins (BMPs) are multifunctional cytokines that elicit pleiotropic effects on biological processes such as cell proliferation, cell differentiation and tissue morphogenesis. With respect to cell proliferation, BMPs can exert either mitogenic or anti-mitogenic activities, depending on the target cells and their context. Here, we report that in low-density cultures of immortalized mammary epithelial cells, BMP-4 did not stimulate cell proliferation by itself. However, when added in combination with suboptimal concentrations of fibroblast growth factor (FGF)-2, FGF-7, FGF-10, epidermal growth factor (EGF) or hepatocyte growth factor (HGF), BMP-4 potently enhanced growth factor-induced cell proliferation. These results reveal a hitherto unsuspected interplay between BMP-4 and growth factors in the regulation of mammary epithelial cell proliferation. We suggest that the ability of BMP-4 to potentiate the mitogenic activity of multiple growth factors may contribute to mammary gland ductal morphogenesis as well as to breast cancer progression.

  13. Soft-sediment deformation structures induced by strong earthquakes in southern Siberia and their paleoseismic significance

    NASA Astrophysics Data System (ADS)

    Lunina, Oksana V.; Gladkov, Andrey S.

    2016-10-01

    Liquefaction-induced soft-sediment deformation structures (SSDS) formed by earthquakes in southern Siberia, that were historically mentioned or monitored by instruments, are described and analyzed. Clastic dikes are the most common among all SSDS in the epicentral areas of the investigated seismic events. They are also the most reliable paleoseismic indicators in regions where cryogenic processes are intense. We suggest seven criteria that may be useful to distinguish the seismogenic clastic dikes from non-seismogenic SSDS in a single outcrop: (1) pushed up sedimentary blocks within the dike body; (2) regular distorted contacts of a dike with host sediments, reflecting cyclic loading during propagation of seismic waves; (3) turned up layers of host deposits on contacts with a dike; (4) displacement along dike contacts usually in the form of a normal fault caused by subsidence that compensates for the removed sediment; (5) a dike structure similar to a diapir; (6) filling of a clasic dike with coarser materials than the host sediments; and (7) a sediment layer extruded on the surface or between strata, similar in composition to the dike. In the extruded sandy-gravel-pebble layer, rock fragments show normal grading (from large to small clasts). In addition to these indicators, fractures may indirectly indicate the seismogenic genesis of liquefaction-induced SSDS. Due to the close spatial relationship of dikes with the fault structures of the investigated areas, they can be used to identify seismogenic fault, and the characteristics of dikes (lateral gradual changes in the frequency, size, and type of the deformations) can help to determine the epicenter, magnitude and the local intensity of the associated earthquakes.

  14. Temperature-tunable Fano resonance induced by strong coupling between Weyl fermions and phonons in TaAs

    PubMed Central

    Xu, B.; Dai, Y. M.; Zhao, L. X.; Wang, K.; Yang, R.; Zhang, W.; Liu, J. Y.; Xiao, H.; Chen, G. F.; Trugman, S. A.; Zhu, J-X; Taylor, A. J.; Yarotski, D. A.; Prasankumar, R. P.; Qiu, X. G.

    2017-01-01

    Strong coupling between discrete phonon and continuous electron–hole pair excitations can induce a pronounced asymmetry in the phonon line shape, known as the Fano resonance. This effect has been observed in various systems. Here we reveal explicit evidence for strong coupling between an infrared-active phonon and electronic transitions near the Weyl points through the observation of a Fano resonance in the Weyl semimetal TaAs. The resulting asymmetry in the phonon line shape, conspicuous at low temperatures, diminishes continuously with increasing temperature. This behaviour originates from the suppression of electronic transitions near the Weyl points due to the decreasing occupation of electronic states below the Fermi level (EF) with increasing temperature, as well as Pauli blocking caused by thermally excited electrons above EF. Our findings not only elucidate the mechanism governing the tunable Fano resonance but also open a route for exploring exotic physical phenomena through phonon properties in Weyl semimetals. PMID:28358027

  15. Aerosol-Induced Changes of Convective Cloud Anvils Produce Strong Climate Warming

    NASA Technical Reports Server (NTRS)

    Koren, I.; Remer, L. A.; Altaratz, O.; Martins, J. V.; Davidi, A.

    2010-01-01

    The effect of aerosol on clouds poses one of the largest uncertainties in estimating the anthropogenic contribution to climate change. Small human-induced perturbations to cloud characteristics via aerosol pathways can create a change in the top-of-atmosphere radiative forcing of hundreds of Wm(exp-2) . Here we focus on links between aerosol and deep convective clouds of the Atlantic and Pacific Intertropical Convergence Zones, noting that the aerosol environment in each region is entirely different. The tops of these vertically developed clouds consisting of mostly ice can reach high levels of the atmosphere, overshooting the lower stratosphere and reaching altitudes greater than 16 km. We show a link between aerosol, clouds and the free atmosphere wind profile that can change the magnitude and sign of the overall climate radiative forcing. We find that increased aerosol loading is associated with taller cloud towers and anvils. The taller clouds reach levels of enhanced wind speeds that act to spread and thin the anvi1 clouds, increasing areal coverage and decreasing cloud optical depth. The radiative effect of this transition is to create a positive radiative forcing (warming) at top-of-atmosphere. Furthermore we introduce the cloud optical depth (r), cloud height (Z) forcing space and show that underestimation of radiative forcing is likely to occur in cases of non homogenous clouds. Specifically, the mean radiative forcing of towers and anvils in the same scene can be several times greater than simply calculating the forcing from the mean cloud optical depth in the scene. Limitations of the method are discussed, alternative sources of aerosol loading are tested and meteorological variance is restricted, but the trend of taller clouds; increased and thinner anvils associated with increased aerosol loading remains robust through all the different tests and perturbations.

  16. Size/morphology induced tunable luminescence in upconversion crystals: ultra-strong single-band emission and underlying mechanisms

    NASA Astrophysics Data System (ADS)

    Wang, Zhaofeng; Zeng, Songshan; Yu, Jingfang; Ji, Xiaoming; Zeng, Huidan; Xin, Shuangyu; Wang, Yuhua; Sun, Luyi

    2015-05-01

    In this work, we present a two-step method to controllably synthesize novel and highly efficient upconversion materials, Lu5O4F7:Er3+,Yb3+ nano/micro-crystals, and investigate their size/morphology induced tunable upconversion properties. In addition to the common phenomenon aroused by a surface quenching effect, direct experimental evidence for the regulation of phonon modes is obtained in nanoparticles. The findings in this work advance the existing mechanisms for the general explanation of size/morphology induced upconversion features. Because of the adjustment of phonon energy and density as well as the surface quenching effect, the biocompatible Lu5O4F7:Er3+,Yb3+ nanoparticles exhibit an ultra-strong single-band red upconversion, rendering them promising for biomedical applications.In this work, we present a two-step method to controllably synthesize novel and highly efficient upconversion materials, Lu5O4F7:Er3+,Yb3+ nano/micro-crystals, and investigate their size/morphology induced tunable upconversion properties. In addition to the common phenomenon aroused by a surface quenching effect, direct experimental evidence for the regulation of phonon modes is obtained in nanoparticles. The findings in this work advance the existing mechanisms for the general explanation of size/morphology induced upconversion features. Because of the adjustment of phonon energy and density as well as the surface quenching effect, the biocompatible Lu5O4F7:Er3+,Yb3+ nanoparticles exhibit an ultra-strong single-band red upconversion, rendering them promising for biomedical applications. Electronic supplementary information (ESI) available: Crystal structure analysis, UV-Vis absorption spectra, SEM micrographs, surface micro-structure investigation, biocompatibility of Lu5O4F7: Er3+, Yb3+, as well as morphology and upconversion properties of the control sample NaYF4: Er3+, Yb3+. See DOI: 10.1039/c5nr01008j

  17. Functional consequences of anti-sense RNA-mediated inhibition of CD8 surface expression in a human T cell clone

    PubMed Central

    1988-01-01

    An experimental approach for defining the function of CD8 has been developed by linking anti-sense RNA mutagenesis and T cell cloning technologies. We have transfected an anti-sense CD8 episomal expression vector into a CD8+ nontransformed human T cell clone that is specific for the human class I alloantigen HLA-B35. Expression of CD8 on this T cell clone, JH.ARL.1, was selectively and efficiently inhibited. Stimulation of this CD8- variant with specific alloantigen resulted in a marked loss of a number of functional responses, including cytotoxicity, proliferation, IL-2 secretion, and IL-2-R expression. However, these same functional responses could be elicited with stimuli that do not require antigen recognition to activate the T cell (anti- CD3 mAbs, PHA). The results of our study support the hypothesis that CD8 is required for recognition of class I MHC alloantigens that results in activation of T cell functional responses. PMID:2459296

  18. Dengue E Protein Domain III-Based DNA Immunisation Induces Strong Antibody Responses to All Four Viral Serotypes

    PubMed Central

    Chan, Kuan Rong; Tan, Hwee Cheng; Bestagno, Marco; Ooi, Eng Eong; Burrone, Oscar R.

    2015-01-01

    Dengue virus (DENV) infection is a major emerging disease widely distributed throughout the tropical and subtropical regions of the world affecting several millions of people. Despite constants efforts, no specific treatment or effective vaccine is yet available. Here we show a novel design of a DNA immunisation strategy that resulted in the induction of strong antibody responses with high neutralisation titres in mice against all four viral serotypes. The immunogenic molecule is an engineered version of the domain III (DIII) of the virus E protein fused to the dimerising CH3 domain of the IgG immunoglobulin H chain. The DIII sequences were also codon-optimised for expression in mammalian cells. While DIII alone is very poorly secreted, the codon-optimised fusion protein is rightly expressed, folded and secreted at high levels, thus inducing strong antibody responses. Mice were immunised using gene-gun technology, an efficient way of intradermal delivery of the plasmid DNA, and the vaccine was able to induce neutralising titres against all serotypes. Additionally, all sera showed reactivity to a recombinant DIII version and the recombinant E protein produced and secreted from mammalian cells in a mono-biotinylated form when tested in a conformational ELISA. Sera were also highly reactive to infective viral particles in a virus-capture ELISA and specific for each serotype as revealed by the low cross-reactive and cross-neutralising activities. The serotype specific sera did not induce antibody dependent enhancement of infection (ADE) in non-homologous virus serotypes. A tetravalent immunisation protocol in mice showed induction of neutralising antibodies against all four dengue serotypes as well. PMID:26218926

  19. Strong resilience of soil respiration components to drought-induced die-off resulting in forest secondary succession.

    PubMed

    Barba, Josep; Curiel Yuste, Jorge; Poyatos, Rafael; Janssens, Ivan A; Lloret, Francisco

    2016-09-01

    How forests cope with drought-induced perturbations and how the dependence of soil respiration on environmental and biological drivers is affected in a warming and drying context are becoming key questions. The aims of this study were to determine whether drought-induced die-off and forest succession were reflected in soil respiration and its components and to determine the influence of climate on the soil respiration components. We used the mesh exclusion method to study seasonal variations in soil respiration (R S) and its components: heterotrophic (R H) and autotrophic (R A) [further split into fine root (R R) and mycorrhizal respiration (R M)] in a mixed Mediterranean forest where Scots pine (Pinus sylvestris L.) is undergoing a drought-induced die-off and is being replaced by holm oak (Quercus ilex L.). Drought-induced pine die-off was not reflected in R S nor in its components, which denotes a high functional resilience of the plant and soil system to pine die-off. However, the succession from Scots pine to holm oak resulted in a reduction of R H and thus in an important decrease of total respiration (R S was 36 % lower in holm oaks than in non-defoliated pines). Furthermore, R S and all its components were strongly regulated by soil water content-and-temperature interaction. Since Scots pine die-off and Quercus species colonization seems to be widely occurring at the driest limit of the Scots pine distribution, the functional resilience of the soil system over die-off and the decrease of R S from Scots pine to holm oak could have direct consequences for the C balance of these ecosystems.

  20. Metal-ligand interplay in strongly correlated oxides: a parametrized phase diagram for pressure-induced spin transitions.

    PubMed

    Mattila, Aleksi; Rueff, Jean-Pascal; Badro, James; Vankó, György; Shukla, Abhay

    2007-05-11

    We investigate the magnetic properties of archetypal transition-metal oxides MnO, FeO, CoO, and NiO under very high pressure by x-ray emission spectroscopy at the Kbeta line. We observe a strong modification of the magnetism in the megabar range in all the samples except NiO. The results are analyzed within a multiplet approach including charge-transfer effects. The spectral changes are well accounted for by changes of the ligand field acting on the d electrons and allows us to extract the d-hybridization strength, O-2p bandwidth and ionic crystal field across the magnetic transition. This approach allows first-hand insight into the mechanism of the pressure-induced spin transition.

  1. Seismic wave attenuation and dispersion due to wave-induced fluid flow in rocks with strong permeability fluctuations.

    PubMed

    Germán Rubino, J; Monachesi, Leonardo B; Müller, Tobias M; Guarracino, Luis; Holliger, Klaus

    2013-12-01

    Oscillatory fluid movements in heterogeneous porous rocks induced by seismic waves cause dissipation of wave field energy. The resulting seismic signature depends not only on the rock compressibility distribution, but also on a statistically averaged permeability. This so-called equivalent seismic permeability does not, however, coincide with the respective equivalent flow permeability. While this issue has been analyzed for one-dimensional (1D) media, the corresponding two-dimensional (2D) and three-dimensional (3D) cases remain unexplored. In this work, this topic is analyzed for 2D random medium realizations having strong permeability fluctuations. With this objective, oscillatory compressibility simulations based on the quasi-static poroelasticity equations are performed. Numerical analysis shows that strong permeability fluctuations diminish the magnitude of attenuation and velocity dispersion due to fluid flow, while the frequency range where these effects are significant gets broader. By comparing the acoustic responses obtained using different permeability averages, it is also shown that at very low frequencies the equivalent seismic permeability is similar to the equivalent flow permeability, while for very high frequencies this parameter approaches the arithmetic average of the permeability field. These seemingly generic findings have potentially important implications with regard to the estimation of equivalent flow permeability from seismic data.

  2. Computational study of vortex-induced vibration of a sprung rigid circular cylinder with a strongly nonlinear internal attachment

    NASA Astrophysics Data System (ADS)

    Tumkur, Ravi Kumar R.; Calderer, Ramon; Masud, Arif; Pearlstein, Arne J.; Bergman, Lawrence A.; Vakakis, Alexander F.

    2013-07-01

    For a Reynolds number (Re) based on cylinder diameter of 100, and a ratio of cylinder density to fluid density of 10, we investigate the effect of a strongly nonlinear internal attachment on the vortex-induced vibration (VIV) of a rigid circular cylinder restrained by a linear spring, and constrained to move perpendicularly to the mean flow. The variational multiscale residual-based stabilized finite-element method used to compute approximate solutions of the incompressible Navier-Stokes equations about the moving cylinder is coupled to a simple model of a "nonlinear energy sink" (NES), an essentially nonlinear oscillator consisting of a mass, a linear damper, and a strongly nonlinear spring. The NES promotes nearly one-way transfer of energy to itself from the primary structure (the cylinder), resulting in reduction of the amplitude of the limit-cycle oscillation by as much as 75%, depending on the parameters characterizing the NES. Various mechanisms of nonlinear interaction of the NES with the cylinder undergoing VIV are discussed. Although no optimization of the NES is performed in this work, we demonstrate capacity for passive suppression of VIV and compare the performance of the NES to the tuned linear absorber of equal mass.

  3. Unusually strong binding to the DNA minor groove by a highly twisted benzimidazole diphenylether: induced fit and bound water.

    PubMed

    Tanious, Farial A; Laine, William; Peixoto, Paul; Bailly, Christian; Goodwin, Kristie D; Lewis, Mark A; Long, Eric C; Georgiadis, Millie M; Tidwell, Richard R; Wilson, W David

    2007-06-12

    RT29 is a dicationic diamidine derivative that does not obey the classical "rules" for shape and functional group placement that are expected to result in strong binding and specific recognition of the DNA minor groove. The compound contains a benzimidazole diphenyl ether core that is flanked by the amidine cations. The diphenyl ether is highly twisted and gives the entire compound too much curvature to fit well to the shape of the minor groove. DNase I footprinting, fluorescence intercalator displacement studies, and circular dichroism spectra, however, indicate that the compound is an AT specific minor groove binding agent. Even more surprisingly, quantitative biosensor-surface plasmon resonance and isothermal titration calorimetric results indicate that the compound binds with exceptional strength to certain AT sequences in DNA with a large negative enthalpy of binding. Crystallographic results for the DNA complex of RT29 compared to calculated results for the free compound show that the compound undergoes significant conformational changes to enhance its minor groove interactions. In addition, a water molecule is incorporated directly into the complex to complete the compound-DNA interface, and it forms an essential link between the compound and base pair edges at the floor of the minor groove. The calculated DeltaCp value for complex formation is substantially less than the experimentally observed value, which supports the idea of water being an intrinsic part of the complex with a major contribution to the DeltaCp value. Both the induced fit conformational changes of the compound and the bound water are essential for strong binding to DNA by RT29.

  4. Mycobacterium vaccae induces a strong Th1 response that subsequently declines in C57BL/6 mice

    PubMed Central

    Zhang, Lijiao; Jiang, Yanlong; Cui, Ziyin; Yang, Wentao; Yue, Limin; Ma, Yingcong; Shi, Shaohua; Wang, Chunfang

    2016-01-01

    Mycobacterium (M.) vaccae is a fast-growing species of saprophytic bacteria that is widely distributed. To understand the host immune responses induced by M. vaccae isolated from bovine submaxillary lymph nodes, C57BL/6 mice were infected with reference strain M. vaccae Bacillus Calmette-Guérin (BCG) and isolated M. vaccae using intraperitoneal injections. Comparison of the bacterial replication and organ pathology between M. vaccae and M. vaccae BCG revealed that M. vaccae was more malignant than M. vaccae in mice. We also demonstrated that serum from the M. vaccae-infected mice contained a higher expression level of gamma-interferon (IFN-γ), tumor necrosis factor alpha, monocyte chemoattractant protein-1, interleukin (IL)-4, IL-12, IL-10 and transforming growth factor beta than did the other groups, especially after week 4. Furthermore, when the numbers of CD3+CD4+IFN-γ+ and CD3+CD4+IL4+ cells in the infected mice were observed by flow cytometry, we found that a powerful T helper 1 (Th1) response was induced by M. vaccae infection, which was associated with the emergence of CD3+CD4+IFN-γ+ cells. However, the Th1 response declined over time, which was associated with appearance of the CD4+CD25+FoxP3+ and CD4+CD25+CD152+Treg cell reaction. In addition, a strong Th2 response was found. Finally, we found that M. vaccae infection increased the production of type I IFNs, which was associated with a reduced Th1 response. PMID:27994210

  5. Strong TCR-mediated signals suppress integrated stress responses induced by KDELR1 deficiency in naive T cells.

    PubMed

    Kamimura, Daisuke; Arima, Yasunobu; Tsuruoka, Mineko; Jiang, Jing-Jing; Bando, Hidenori; Meng, Jie; Sabharwal, Lavannya; Stofkova, Andrea; Nishikawa, Naoki; Higuchi, Kotaro; Ogura, Hideki; Atsumi, Toru; Murakami, Masaaki

    2016-03-01

    KDEL receptor 1 (KDELR1) regulates integrated stress responses (ISR) to promote naive T-cell survival in vivo. In a mouse line having nonfunctional KDELR1, T-Red (naive T-cell reduced) mice, polyclonal naive T cells show excessive ISR and eventually undergo apoptosis. However, breeding T-Red mice with TCR-transgenic mice bearing relatively high TCR affinity rescued the T-Red phenotype, implying a link between ISR-induced apoptosis and TCR-mediated signaling. Here, we showed that strong TCR stimulation reduces ISR in naive T cells. In mice lacking functional KDELR1, surviving naive T cells expressed significantly higher levels of CD5, a surrogate marker of TCR self-reactivity. In addition, higher TCR affinity/avidity was confirmed using a tetramer dissociation assay on the surviving naive T cells, suggesting that among the naive T-cell repertoire, those that receive relatively stronger TCR-mediated signals via self-antigens survive enhanced ISR. Consistent with this observation, weak TCR stimulation with altered peptide ligands decreased the survival and proliferation of naive T cells, whereas stimulation with ligands having higher affinity had no such effect. These results suggest a novel role of TCR-mediated signals in the attenuation of ISR in vivo.

  6. Naegleria fowleri lysate induces strong cytopathic effects and pro-inflammatory cytokine release in rat microglial cells.

    PubMed

    Lee, Yang-Jin; Park, Chang-Eun; Kim, Jong-Hyun; Sohn, Hae-Jin; Lee, Jinyoung; Jung, Suk-Yul; Shin, Ho-Joon

    2011-09-01

    Naegleria fowleri, a ubiquitous free-living ameba, causes fatal primary amebic meningoencephalitis in humans. N. fowleri trophozoites are known to induce cytopathic changes upon contact with microglial cells, including necrotic and apoptotic cell death and pro-inflammatory cytokine release. In this study, we treated rat microglial cells with amebic lysate to probe contact-independent mechanisms for cytotoxicity, determining through a combination of light microscopy and scanning and transmission electron microscopy whether N. fowleri lysate could effect on both necrosis and apoptosis on microglia in a time- as well as dose-dependent fashion. A (51)Cr release assay demonstrated pronounced lysate induction of cytotoxicity (71.5%) toward microglial cells by 24 hr after its addition to cultures. In an assay of pro-inflammatory cytokine release, microglial cells treated with N. fowleri lysate produced TNF-α, IL-6, and IL-1β, though generation of the former 2 cytokines was reduced with time, and that of the last increased throughout the experimental period. In summary, N. fowleri lysate exerted strong cytopathic effects on microglial cells, and elicited pro-inflammatory cytokine release as a primary immune response.

  7. Sun-induced chlorophyll fluorescence reveals strong representation of photosynthesis at ecosystem level in rice paddy field in Japan

    NASA Astrophysics Data System (ADS)

    Kato, T.; Tsujimoto, K.; Nasahara, K. N.; Akitsu, T.; Ono, K.; Miyata, A.

    2015-12-01

    Chlorophyll fluorescence emission from ecosystem induced by sunlight (Sun-Induced Fluorescence: SIF) is now a key factor to accurately estimate the ecosystem-level photosynthesis activity as suggested by satellite studies, and has been recently detected by satellites [Frankenberg et al., 2011; Guanter et al., 2012; Joiner et al., 2013] and measured at field stations [Daumard et al., 2010; Porcar-Castell, 2011]. However, the few example of field-based assessment on the representation ability reduces its value for the availability to better understand the dynamics in CO2uptake by land ecosystem. To elucidate the potential of SIF to estimate ecosystem GPP in typical Asian crop type, the canopy-top SIF was calculated from the spectrum data in Japanese rice paddy field in Mase in central Japan (36°03'N, 140°01'E, 11 m a.s.l.), and compared with eddy-tower measured GPP on half-hourly and daily bases during seven years from 2006 to 2012. The rice (Oriza sativa L.; cultivar Koshihikari) was transplanted in May and harvested in September normally. The SIF was estimated from the spectrums of downward Sun irradiance and upward canopy-reflected radiance measured at the height of 3m above ground by HemiSpherical Spectro-Radiometer (HSSR), consisting of the spectroradiometer (MS-700, Eko inc., Tokyo, Japan) with the full-width at half maximum (FWHM) of 10 nm and wavelength interval of 3.3 nm. The SIF around 760nm (O2-A band: Fs760) was calculated according to the Fraunhofer Line Depth principle [Maier et al., 2003] with several additional arrangements. The GPP increased almost linearly as both Fs760 and APAR (Absorbed Photosyntethically Active Radiation) increased based on monthly-averaged diurnal courses during the growing season in 2006. The slopes of their regression lines differed much among the months in APAR, but in Fs760. These nearly constant relationships among the months between GPP and Fs760 were kept for all the observation years. Daily averaged GPP and Fs760

  8. Tendon progenitor cells in injured tendons have strong chondrogenic potential: the CD105-negative subpopulation induces chondrogenic degeneration.

    PubMed

    Asai, Shuji; Otsuru, Satoru; Candela, Maria Elena; Cantley, Leslie; Uchibe, Kenta; Hofmann, Ted J; Zhang, Kairui; Wapner, Keith L; Soslowsky, Louis J; Horwitz, Edwin M; Enomoto-Iwamoto, Motomi

    2014-12-01

    To study the cellular mechanism of the tendon repair process, we used a mouse Achilles tendon injury model to focus on the cells recruited to the injured site. The cells isolated from injured tendon 1 week after the surgery and uninjured tendons contained the connective tissue progenitor populations as determined by colony-forming capacity, cell surface markers, and multipotency. When the injured tendon-derived progenitor cells (inTPCs) were transplanted into injured Achilles tendons, they were not only integrated in the regenerating area expressing tenogenic phenotype but also trans-differentiated into chondrogenic cells in the degenerative lesion that underwent ectopic endochondral ossification. Surprisingly, the micromass culture of the inTPCs rapidly underwent chondrogenic differentiation even in the absence of exogenous bone morphogenetic proteins or TGFβs. The cells isolated from human ruptured tendon tissues also showed connective tissue progenitor properties and exhibited stronger chondrogenic ability than bone marrow stromal cells. The mouse inTPCs contained two subpopulations one positive and one negative for CD105, a coreceptor of the TGFβ superfamily. The CD105-negative cells showed superior chondrogenic potential in vitro and induced larger chondroid degenerative lesions in mice as compared to the CD105-positive cells. These findings indicate that tendon progenitor cells are recruited to the injured site of tendons and have a strong chondrogenic potential and that the CD105-negative population of these cells would be the cause for chondroid degeneration in injured tendons. The newly identified cells recruited to the injured tendon may provide novel targets to develop therapeutic strategies to facilitate tendon repair.

  9. Synonymous Deoptimization of Foot-and-Mouth Disease Virus Causes Attenuation In Vivo while Inducing a Strong Neutralizing Antibody Response

    PubMed Central

    Diaz-San Segundo, Fayna; Medina, Gisselle N.; Ramirez-Medina, Elizabeth; Velazquez-Salinas, Lauro; Koster, Marla; Grubman, Marvin J.

    2015-01-01

    ABSTRACT Codon bias deoptimization has been previously used to successfully attenuate human pathogens, including poliovirus, respiratory syncytial virus, and influenza virus. We have applied a similar technology to deoptimize the capsid-coding region (P1) of foot-and-mouth disease virus (FMDV). Despite the introduction of 489 nucleotide changes (19%), synonymous deoptimization of the P1 region rendered a viable FMDV progeny. The resulting strain was stable and reached cell culture titers similar to those obtained for wild-type (WT) virus, but at reduced specific infectivity. Studies in mice showed that 100% of animals inoculated with the FMDV A12 P1 deoptimized mutant (A12-P1 deopt) survived, even when the animals were infected at doses 100 times higher than the dose required to cause death by WT virus. All mice inoculated with the A12-P1 deopt mutant developed a strong antibody response and were protected against subsequent lethal challenge with WT virus at 21 days postinoculation. Remarkably, the vaccine safety margin was at least 1,000-fold higher for A12-P1 deopt than for WT virus. Similar patterns of attenuation were observed in swine, in which animals inoculated with A12-P1 deopt virus did not develop clinical disease until doses reached 1,000 to 10,000 times the dose required to cause severe disease in 2 days with WT A12. Consistently, high levels of antibody titers were induced, even at the lowest dose tested. These results highlight the potential use of synonymous codon pair deoptimization as a strategy to safely attenuate FMDV and further develop live attenuated vaccine candidates to control such a feared livestock disease. IMPORTANCE Foot-and-mouth disease (FMD) is one of the most feared viral diseases that can affect livestock. Although this disease appeared to be contained in developed nations by the end of the last century, recent outbreaks in Europe, Japan, Taiwan, South Korea, etc., have demonstrated that infection can spread rapidly, causing

  10. Strong synergistic induction of CYP1A1 expression by andrographolide plus typical CYP1A inducers in mouse hepatocytes

    SciTech Connect

    Jaruchotikamol, Atika; Jarukamjorn, Kanokwan Sirisangtrakul, Wanna; Sakuma, Tsutomu; Kawasaki, Yuki; Nemoto, Nobuo

    2007-10-15

    The effects of andrographolide, the major diterpenoid constituent of Andrographis paniculata, on the expression of cytochrome P450 superfamily 1 members, including CYP1A1, CYP1A2, and CYP1B1, as well as on aryl hydrocarbon receptor (AhR) expression in primary cultures of mouse hepatocytes were investigated in comparison with the effects of typical CYP1A inducers, including benz[a]anthracene, {beta}-naphthoflavone, and 2,3,7,8-tetrachlorodibenzo-p-dioxin. Andrographolide significantly induced the expression of CYP1A1 and CYP1A2 mRNAs in a concentration-dependent manner, as did the typical CYP1A inducers, but did not induce that of CYP1B1 or AhR. Interestingly, andrographolide plus the typical CYP1A inducers synergistically induced CYP1A1 expression, and the synergism was blocked by an AhR antagonist, resveratrol. The CYP1A1 enzyme activity showed a similar pattern of induction. This is the first report that shows that andrographolide has a potency to induce CYP1A1 enzyme and indicates that andrographolide could be a very useful compound for investigating the regulatory mechanism of the CYP1A1 induction pathway. In addition, our findings suggest preparing advice for rational administration of A. paniculata, according to its ability to induce CYP1A1 expression.

  11. Alignment- and orientation-dependent strong-field ionization of molecules: Field-induced orbital distortion effects

    NASA Astrophysics Data System (ADS)

    Spiewanowski, Maciej Dominik; Madsen, Lars Bojer

    2015-05-01

    Strong-field ionization (SFI) is a starting point for many strong-field phenomena, e.g., high-order harmonic generation, as well as a source of fundamental information about the ionized target. Therefore, investigation of SFI of atoms and molecules has been the aim for research since the first strong laser pulses became available. We present a recently developed method, adiabatic strong-field approximation, to study ionization yields as a function of alignment angle for CO2, CO, and OCS molecules. We show that orbital distortion plays an important role in explaining the position and relative strength of maxima in the yields for both polar and nonpolar molecules, even for targets with low polarizabilities at low laser intensities. In particular, we report that for ionization of CO2 the maximum in ionization yield shifts towards the experimentally-measured maximum with respect to the strong-field approximation. For ionization of the CO molecule, not only does the theory predict the preferred direction of ionization correctly, but also the ratio between yields for the two molecular orientations where the electric field points either towards the C or towards the O end. Finally, we find that ionization of OCS is more probable for the laser pointing from the O end towards the S end. Work supported by the Natural Sciences and Engineering Research Council of Canada, the ERC-StG (Project No. 277767-TDMET), and the VKR center of excellence, QUS- COPE.

  12. Strong Interaction

    SciTech Connect

    Karsch, F.; Vogelsang, V.

    2009-09-29

    We will give here an overview of our theory of the strong interactions, Quantum Chromo Dynamics (QCD) and its properties. We will also briefly review the history of the study of the strong interactions, and the discoveries that ultimately led to the formulation of QCD. The strong force is one of the four known fundamental forces in nature, the others being the electromagnetic, the weak and the gravitational force. The strong force, usually referred to by scientists as the 'strong interaction', is relevant at the subatomic level, where it is responsible for the binding of protons and neutrons to atomic nuclei. To do this, it must overcome the electric repulsion between the protons in an atomic nucleus and be the most powerful force over distances of a few fm (1fm=1 femtometer=1 fermi=10{sup -15}m), the typical size of a nucleus. This property gave the strong force its name.

  13. Strong hyperfine-induced modulation of an optically driven hole spin in an InAs quantum dot

    NASA Astrophysics Data System (ADS)

    Carter, S. G.; Economou, Sophia E.; Greilich, A.; Barnes, Edwin; Sweeney, T.; Bracker, A. S.; Gammon, D.

    2014-02-01

    Compared to electrons, holes in InAs quantum dots have a significantly weaker hyperfine interaction that leads to less dephasing from nuclear spins. Thus many recent studies have suggested that nuclear spins are unimportant for hole-spin dynamics compared to electric-field fluctuations. We show that the hole hyperfine interaction can have a strong effect on hole-spin coherence measurements through a nuclear feedback effect. The nuclear polarization is generated through a unique process that is dependent on the anisotropy of the hole hyperfine interaction and the coherent precession of nuclear spins, giving rise to strong modulation at the nuclear precession frequency.

  14. Tunability over three frequency bands induced by mode transition in relativistic backward wave oscillator with strong end reflections

    NASA Astrophysics Data System (ADS)

    Wu, Ping; Fan, Juping; Teng, Yan; Shi, Yanchao; Deng, Yuqun; Sun, Jun

    2014-10-01

    This paper presents an efficient approach to realizing the frequency tunability of a relativistic backward wave oscillator (RBWO) over three frequency bands by mode transition without changing the slow wave structure (SWS). It is figured out that the transition of the operation mode in the RBWO can be efficiently achieved by using the strong end reflection of the SWS. This mode transition results in the tunability of the RBWO over three frequency bands at high power and high efficiency without changing the SWS. In numerical simulation, the output frequency of the RBWO can jump over 7.9 GHz in C-band, 9.9 GHz in X-band, and 12.4 GHz in Ku-band with output power exceeding 3.0 GW and conversion efficiency higher than 35% by just reasonably transforming the structures of the front and post resonant reflectors which provide the strong end reflection for the SWS.

  15. EB 1089, a novel vitamin D analogue, has strong antiproliferative and differentiation inducing effects on cancer cells.

    PubMed

    Mathiasen, I S; Colston, K W; Binderup, L

    1993-09-01

    EB 1089 is a novel vitamin D analogue which in vitro strongly inhibits the proliferation of U937 histiocytic lymphoma cells and MCF-7 breast cancer cells, with a potency of 50 to 100 times that of 1,25-dihydroxyvitamin D3 [1,25(OH)2D3]. Studies of c-myc and c-fos expression in MCF-7 cells and of differentiation markers in U937 cells show that growth inhibition by EB 1089 is accompanied by induction of differentiation. The ability of EB 1089 to affect calcium metabolism in vivo in rats is decreased, compared to 1,25(OH)2D3. This low calcemic effect combined with the strong biological effect on cancer cells in vitro, makes EB 1089 an interesting candidate for treatment of cancer.

  16. Strong thermo-induced single and two-photon green luminescence in self-organized peptide microtubes.

    PubMed

    Semin, S; van Etteger, A; Cattaneo, L; Amdursky, N; Kulyuk, L; Lavrov, S; Sigov, A; Mishina, E; Rosenman, G; Rasing, Th

    2015-03-01

    Diphenylalanine peptide nano- and microtubes formed by self-assembly demonstrate strongly enhanced and tunable single-photon and two-photon luminescence in the visible range, which appears after heat- or laser treatment of these self-organized peptide microtubes. This process significantly extends the functionality of these microstructures and can trigger a new interest in the optical properties of structures based on short peptides.

  17. Strong covalency-induced recombination centers in perovskite solar cell material CH3NH3PbI3.

    PubMed

    Agiorgousis, Michael L; Sun, Yi-Yang; Zeng, Hao; Zhang, Shengbai

    2014-10-15

    Inorganic-organic hybrid perovskites are a new family of solar cell materials, which have recently been used to make solar cells with efficiency approaching 20%. Here, we report the unique defect chemistry of the prototype material, CH3NH3PbI3, based on first-principles calculation. We found that both the Pb cations and I anions in this material exhibit strong covalency as characterized by the formation of Pb dimers and I trimers with strong covalent bonds at some of the intrinsic defects. The Pb dimers and I trimers are only stabilized in a particular charge state with significantly lowered energy, which leads to deep charge-state transition levels within the band gap, in contradiction to a recent proposal that this system has only shallow intrinsic defects. Our results show that, in order to prevent the deep-level defects from being effective recombination centers, the equilibrium carrier concentrations should be controlled so that the Fermi energy is about 0.3 eV away from the band edges. Beyond this range, according to a Shockley-Read-Hall analysis, the non-equilibrium carrier lifetime will be strongly affected by the concentration of I vacancies and the anti-site defects with I occupying a CH3NH3 site.

  18. Dual role of the p38 MAPK/cPLA2 pathway in the regulation of platelet apoptosis induced by ABT-737 and strong platelet agonists

    PubMed Central

    Rukoyatkina, N; Mindukshev, I; Walter, U; Gambaryan, S

    2013-01-01

    p38 Mitogen-activated protein (MAP) kinase is involved in the apoptosis of nucleated cells. Although platelets are anucleated cells, apoptotic proteins have been shown to regulate platelet lifespan. However, the involvement of p38 MAP kinase in platelet apoptosis is not yet clearly defined. Therefore, we investigated the role of p38 MAP kinase in apoptosis induced by a mimetic of BH3-only proteins, ABT-737, and in apoptosis-like events induced by such strong platelet agonists as thrombin in combination with convulxin (Thr/Cvx), both of which result in p38 MAP kinase phosphorylation and activation. A p38 inhibitor (SB202190) inhibited the apoptotic events induced by ABT-737 but did not influence those induced by Thr/Cvx. The inhibitor also reduced the phosphorylation of cytosolic phospholipase A2 (cPLA2), an established p38 substrate, induced by ABT-737 or Thr/Cvx. ABT-737, but not Thr/Cvx, induced the caspase 3-dependent cleavage and inactivation of cPLA2. Thus, p38 MAPK promotes ABT-737-induced apoptosis by inhibiting the cPLA2/arachidonate pathway. We also show that arachidonic acid (AA) itself and in combination with Thr/Cvx or ABT-737 at low concentrations prevented apoptotic events, whereas at high concentrations it enhanced such events. Our data support the hypothesis that the p38 MAPK-triggered arachidonate pathway serves as a defense mechanism against apoptosis under physiological conditions. PMID:24263105

  19. Control of strong ground motion of mining-induced earthquakes by the strength of the seismogenic rock mass

    USGS Publications Warehouse

    McGarr, A.

    2002-01-01

    The shear stress ?? that can be sustained by the rock mass in the environs of a mining-induced earthquake controls the near-fault peak ground velocity v of that event according to v???0.25(??/G) ??, where ?? is the shear wave speed and G is the modulus of rigidity. To estimate ?? at mining depths, I review the results of four studies involving Witwatersrand tremors that relate to the bulk shear strength. The first and most general analysis uses the common assumptions that the seismogenic crust is pervasively faulted, has hydrostatic pore pressure before mining, and an extensional stress state that is close to failure. Mining operations reduce the pore pressure to zero within the mine and redistribute the stresses such that, in localized regions, the state of stress is again at the point of failure. Laboratory friction experiments can be used to estimate ?? in the zero-pore-pressure regime. Second, model calculations of states of stress in the vicinity of milling at about 3 km depth indicated the shear stress available to cause faulting near the centre of a distribution of induced earthquakes. Third, laboratory experiments combined with microscopic analyses of fault gouge from the rupture zone of a mining-induced event provided an estimate of the average shear stress acting on the fault to cause this earthquake at a depth of 2 km. Fourth, moment tensors determined for mining- induced earthquakes usually show substantial implosive components, from which it is straightforward to estimate ??. These four different analyses yield estimates of ?? that fall in the range 30 to 61 MPa which implies that near-fault particle velocities could he as high as about 1.5 m/s. To the extent that the causative fault ruptures previously intact rock, both ?? and v, in localized regions, could be several times higher than 61 MPa and 1.5 m/s.

  20. Ferromagnetism: Sulfur Doping Induces Strong Ferromagnetic Ordering in Graphene: Effect of Concentration and Substitution Mechanism (Adv. Mater. 25/2016).

    PubMed

    Tuček, Jiří; Błoński, Piotr; Sofer, Zdeněk; Šimek, Petr; Petr, Martin; Pumera, Martin; Otyepka, Michal; Zbořil, Radek

    2016-07-01

    R. Zbořil and co-workers show that doping a graphene lattice with sulfur induces magnetic centers which display ferromagnetic order below ≈62 K. As described on page 5045, sulfur doping promotes magnetically active configurations resembling the gamma-thiothiapyrone motif. Enhanced magnetic properties of sulfur-doped graphene are attributed to two unpaired electrons from each sulfur atom injected into the graphene conducting band where they are delocalized between the S and C atoms.

  1. SiRNAs conjugated with aromatic compounds induce RISC-mediated antisense strand selection and strong gene-silencing activity

    SciTech Connect

    Kubo, Takanori; Yanagihara, Kazuyoshi; Takei, Yoshifumi; Mihara, Keichiro; Sato, Yuichiro; Seyama, Toshio

    2012-10-05

    Highlights: Black-Right-Pointing-Pointer SiRNAs conjugated with aromatic compounds (Ar-siRNAs) at 5 Prime -sense strand were synthesized. Black-Right-Pointing-Pointer Ar-siRNAs increased resistance against nuclease degradation. Black-Right-Pointing-Pointer Ar-siRNAs were thermodynamically stable compared with the unmodified siRNA. Black-Right-Pointing-Pointer High levels of cellular uptake and cytoplasmic localization were found. Black-Right-Pointing-Pointer Strong gene-silencing efficacy was exhibited in the Ar-siRNAs. -- Abstract: Short interference RNA (siRNA) is a powerful tool for suppressing gene expression in mammalian cells. In this study, we focused on the development of siRNAs conjugated with aromatic compounds in order to improve the potency of RNAi and thus to overcome several problems with siRNAs, such as cellular delivery and nuclease stability. The siRNAs conjugated with phenyl, hydroxyphenyl, naphthyl, and pyrenyl derivatives showed strong resistance to nuclease degradation, and were thermodynamically stable compared with unmodified siRNA. A high level of membrane permeability in HeLa cells was also observed. Moreover, these siRNAs exhibited enhanced RNAi efficacy, which exceeded that of locked nucleic acid (LNA)-modified siRNAs, against exogenous Renilla luciferase in HeLa cells. In particular, abundant cytoplasmic localization and strong gene-silencing efficacy were found in the siRNAs conjugated with phenyl and hydroxyphenyl derivatives. The novel siRNAs conjugated with aromatic compounds are promising candidates for a new generation of modified siRNAs that can solve many of the problems associated with RNAi technology.

  2. A Bacterial Flagellin, Vibrio vulnificus FlaB, Has a Strong Mucosal Adjuvant Activity To Induce Protective Immunity

    PubMed Central

    Lee, Shee Eun; Kim, Soo Young; Jeong, Byung Chul; Kim, Young Ran; Bae, Soo Jang; Ahn, Ouk Seon; Lee, Je-Jung; Song, Ho-Chun; Kim, Jung Mogg; Choy, Hyon E.; Chung, Sun Sik; Kweon, Mi-Na; Rhee, Joon Haeng

    2006-01-01

    Flagellin, the structural component of flagellar filament in various locomotive bacteria, is the ligand for Toll-like receptor 5 (TLR5) of host cells. TLR stimulation by various pathogen-associated molecular patterns leads to activation of innate and subsequent adaptive immune responses. Therefore, TLR ligands are considered attractive adjuvant candidates in vaccine development. In this study, we show the highly potent mucosal adjuvant activity of a Vibrio vulnificus major flagellin (FlaB). Using an intranasal immunization mouse model, we observed that coadministration of the flagellin with tetanus toxoid (TT) induced significantly enhanced TT-specific immunoglobulin A (IgA) responses in both mucosal and systemic compartments and IgG responses in the systemic compartment. The mice immunized with TT plus FlaB were completely protected from systemic challenge with a 200× minimum lethal dose of tetanus toxin. Radiolabeled FlaB administered into the nasal cavity readily reached the cervical lymph nodes and systemic circulation. FlaB bound directly to human TLR5 expressed on cultured epithelial cells and consequently induced NF-κB and interleukin-8 activation. Intranasally administered FlaB colocalized with CD11c as patches in putative dendritic cells and caused an increase in the number of TLR5-expressing cells in cervical lymph nodes. These results indicate that flagellin would serve as an efficacious mucosal adjuvant inducing protective immune responses through TLR5 activation. PMID:16369026

  3. Strong Electron-Phonon Coupling Superconductivity Induced by a Low-Lying Phonon in IrGe

    SciTech Connect

    Hirai, Daigorou; Ali, Mazhar N.; Cava, Robert J.

    2014-02-26

    The physical properties of the previously reported superconductor IrGe and the Rh1-xIrxGe solid solution are investigated. IrGe has an exceptionally high superconducting transition temperature (Tc=4.7 K) among the isostructural 1:1 late-metal germanides MGe (M=Rh, Pd, Ir, and Pt). Specific-heat measurements reveal that IrGe has an anomalously low Debye temperature, originating from a low-lying phonon, compared to the other MGe phases. A large jump at Tc in the specific-heat data clearly indicates that IrGe is a strong coupling superconductor. In the Rh1-xIrxGe solid solution, a relationship between an anomalous change in lattice constants and the Debye temperature is observed. We conclude that the unusually high Tc for IrGe is likely due to strong electron–phonon coupling derived from the presence of a low-lying phonon.

  4. Tunability over three frequency bands induced by mode transition in relativistic backward wave oscillator with strong end reflections

    SciTech Connect

    Wu, Ping; Deng, Yuqun; Fan, Juping; Teng, Yan; Shi, Yanchao; Sun, Jun

    2014-10-15

    This paper presents an efficient approach to realizing the frequency tunability of a relativistic backward wave oscillator (RBWO) over three frequency bands by mode transition without changing the slow wave structure (SWS). It is figured out that the transition of the operation mode in the RBWO can be efficiently achieved by using the strong end reflection of the SWS. This mode transition results in the tunability of the RBWO over three frequency bands at high power and high efficiency without changing the SWS. In numerical simulation, the output frequency of the RBWO can jump over 7.9 GHz in C-band, 9.9 GHz in X-band, and 12.4 GHz in Ku-band with output power exceeding 3.0 GW and conversion efficiency higher than 35% by just reasonably transforming the structures of the front and post resonant reflectors which provide the strong end reflection for the SWS.

  5. Strong Rashba-Edelstein Effect-Induced Spin-Orbit Torques in Monolayer Transition Metal Dichalcogenide/Ferromagnet Bilayers.

    PubMed

    Shao, Qiming; Yu, Guoqiang; Lan, Yann-Wen; Shi, Yumeng; Li, Ming-Yang; Zheng, Cheng; Zhu, Xiaodan; Li, Lain-Jong; Amiri, Pedram Khalili; Wang, Kang L

    2016-12-14

    The electronic and optoelectronic properties of two-dimensional materials have been extensively explored in graphene and layered transition metal dichalcogenides (TMDs). Spintronics in these two-dimensional materials could provide novel opportunities for future electronics, for example, efficient generation of spin current, which should enable the efficient manipulation of magnetic elements. So far, the quantitative determination of charge current-induced spin current and spin-orbit torques (SOTs) on the magnetic layer adjacent to two-dimensional materials is still lacking. Here, we report a large SOT generated by current-induced spin accumulation through the Rashba-Edelstein effect in the composites of monolayer TMD (MoS2 or WSe2)/CoFeB bilayer. The effective spin conductivity corresponding to the SOT turns out to be almost temperature-independent. Our results suggest that the charge-spin conversion in the chemical vapor deposition-grown large-scale monolayer TMDs could potentially lead to high energy efficiency for magnetization reversal and convenient device integration for future spintronics based on two-dimensional materials.

  6. Interstitial atoms enable joint twinning and transformation induced plasticity in strong and ductile high-entropy alloys

    PubMed Central

    Li, Zhiming; Tasan, Cemal Cem; Springer, Hauke; Gault, Baptiste; Raabe, Dierk

    2017-01-01

    High-entropy alloys (HEAs) consisting of multiple principle elements provide an avenue for realizing exceptional mechanical, physical and chemical properties. We report a novel strategy for designing a new class of HEAs incorporating the additional interstitial element carbon. This results in joint activation of twinning- and transformation-induced plasticity (TWIP and TRIP) by tuning the matrix phase’s instability in a metastable TRIP-assisted dual-phase HEA. Besides TWIP and TRIP, such alloys benefit from massive substitutional and interstitial solid solution strengthening as well as from the composite effect associated with its dual-phase structure. Nanosize particle formation and grain size reduction are also utilized. The new interstitial TWIP-TRIP-HEA thus unifies all metallic strengthening mechanisms in one material, leading to twice the tensile strength compared to a single-phase HEA with similar composition, yet, at identical ductility. PMID:28079175

  7. Interstitial atoms enable joint twinning and transformation induced plasticity in strong and ductile high-entropy alloys.

    PubMed

    Li, Zhiming; Tasan, Cemal Cem; Springer, Hauke; Gault, Baptiste; Raabe, Dierk

    2017-01-12

    High-entropy alloys (HEAs) consisting of multiple principle elements provide an avenue for realizing exceptional mechanical, physical and chemical properties. We report a novel strategy for designing a new class of HEAs incorporating the additional interstitial element carbon. This results in joint activation of twinning- and transformation-induced plasticity (TWIP and TRIP) by tuning the matrix phase's instability in a metastable TRIP-assisted dual-phase HEA. Besides TWIP and TRIP, such alloys benefit from massive substitutional and interstitial solid solution strengthening as well as from the composite effect associated with its dual-phase structure. Nanosize particle formation and grain size reduction are also utilized. The new interstitial TWIP-TRIP-HEA thus unifies all metallic strengthening mechanisms in one material, leading to twice the tensile strength compared to a single-phase HEA with similar composition, yet, at identical ductility.

  8. Interstitial atoms enable joint twinning and transformation induced plasticity in strong and ductile high-entropy alloys

    NASA Astrophysics Data System (ADS)

    Li, Zhiming; Tasan, Cemal Cem; Springer, Hauke; Gault, Baptiste; Raabe, Dierk

    2017-01-01

    High-entropy alloys (HEAs) consisting of multiple principle elements provide an avenue for realizing exceptional mechanical, physical and chemical properties. We report a novel strategy for designing a new class of HEAs incorporating the additional interstitial element carbon. This results in joint activation of twinning- and transformation-induced plasticity (TWIP and TRIP) by tuning the matrix phase’s instability in a metastable TRIP-assisted dual-phase HEA. Besides TWIP and TRIP, such alloys benefit from massive substitutional and interstitial solid solution strengthening as well as from the composite effect associated with its dual-phase structure. Nanosize particle formation and grain size reduction are also utilized. The new interstitial TWIP-TRIP-HEA thus unifies all metallic strengthening mechanisms in one material, leading to twice the tensile strength compared to a single-phase HEA with similar composition, yet, at identical ductility.

  9. Control of dynamical self-assembly of strongly Brownian nanoparticles through convective forces induced by ultrafast laser

    NASA Astrophysics Data System (ADS)

    Ilday, Serim; Akguc, Gursoy B.; Tokel, Onur; Makey, Ghaith; Yavuz, Ozgun; Yavuz, Koray; Pavlov, Ihor; Ilday, F. Omer; Gulseren, Oguz

    We report a new dynamical self-assembly mechanism, where judicious use of convective and strong Brownian forces enables effective patterning of colloidal nanoparticles that are almost two orders of magnitude smaller than the laser beam. Optical trapping or tweezing effects are not involved, but the laser is used to create steep thermal gradients through multi-photon absorption, and thereby guide the colloids through convective forces. Convective forces can be thought as a positive feedback mechanism that helps to form and reinforce pattern, while Brownian motion act as a competing negative feedback mechanism to limit the growth of the pattern, as well as to increase the possibilities of bifurcation into different patterns, analogous to the competition observed in reaction-diffusion systems. By steering stochastic processes through these forces, we are able to gain control over the emergent pattern such as to form-deform-reform of a pattern, to change its shape and transport it spatially within seconds. This enables us to dynamically initiate and control large patterns comprised of hundreds of colloids. Further, by not relying on any specific chemical, optical or magnetic interaction, this new method is, in principle, completely independent of the material type being assembled.

  10. Recombinant Newcastle Disease virus capsids displaying enterovirus 71 VP1 fragment induce a strong immune response in rabbits.

    PubMed

    Sivasamugham, Lalita Ambigai; Cardosa, Mary Jane; Tan, Wen Siang; Yusoff, Khatijah

    2006-08-01

    The complete VP1 protein of EV71 was truncated into six segments and fused to the C-terminal ends of full-length nucleocapsid protein (NPfl) and truncated NP (NPt; lacks 20% amino acid residues from its C-terminal end) of newcastle disease virus (NDV). Western blot analysis using anti-VP1 rabbit serum showed that the N-terminal region of the VP1 protein contains a major antigenic region. The recombinant proteins carrying the truncated VP1 protein, VP1(1-100), were expressed most efficiently in Escherichia coli as determined by Western blot analysis. Electron microscopic analysis of the purified recombinant protein, NPt-VP(1-100) revealed that it predominantly self-assembled into intact ring-like structures whereas NPfl-VP(1-100) recombinant proteins showed disrupted ring-like formations. Rabbits immunized with the purified NPt-VP(1-100) and NPfl-VP(1-100) exhibited a strong immune response against the complete VP1 protein. The antisera of these recombinant proteins also reacted positively with authentic enterovirus 71 and the closely related Coxsackievirus A16 when analyzed by an immunofluorescence assay suggesting their potential as immunological reagents for the detection of anti-enterovirus 71 antibodies in serum samples.

  11. Strong protection against ricin challenge induced by a novel modified ricin A-chain protein in mouse model

    PubMed Central

    Zhang, Tao; Yang, Hao; Kang, Lin; Gao, Shan; Xin, Wenwen; Yao, Wenwu; Zhuang, Xiangjin; Ji, Bin; Wang, Jinglin

    2015-01-01

    Ricin toxin (RT) is an extremely potent toxin derived from the castor bean plant. As a possible bioterrorist weapon, it was categorized as a level B agent in international society. With the growing awareness and concerns of the “white powder incident” in recent years, it is indispensable to develop an effective countermeasure against RT intoxication. In this study we used site-directed mutagenesis and polymerase chain reaction (PCR) techniques to modify the gene of ricin A-chain (RTA). As a result, we have generated a mutated and truncated ricin A-chain (mtRTA) vaccine antigen by E.coli strain. The cytotoxicity assay was used to evaluate the safety of the as-prepared mtRTA antigen, and the results showed that there was no residual toxicity observed when compared to the recombinant RTA (rRTA) or native RT. Furthermore, BALB/c mice were subcutaneously (s.c.) vaccinated with mtRTA 3 times at an interval of 2 weeks, and then the survivals were evaluated after intraperitoneal (i.p.) or intratracheal challenge of RT. The vaccinated mice developed a strong protective immune response that was wholly protective against 40 × LD50 of RT i.p. injection or 20 × LD50 of RT intratracheal spraying. The mtRTA antigen has great potential to be a vaccine candidate for future application in humans. PMID:26038805

  12. Qubit-flip-induced cavity mode squeezing in the strong dispersive regime of the quantum Rabi model

    PubMed Central

    Joshi, Chaitanya; Irish, Elinor K.; Spiller, Timothy P.

    2017-01-01

    Squeezed states of light are a set of nonclassical states in which the quantum fluctuations of one quadrature component are reduced below the standard quantum limit. With less noise than the best stabilised laser sources, squeezed light is a key resource in the field of quantum technologies and has already improved sensing capabilities in areas ranging from gravitational wave detection to biomedical applications. In this work we propose a novel technique for generating squeezed states of a confined light field strongly coupled to a two-level system, or qubit, in the dispersive regime. Utilising the dispersive energy shift caused by the interaction, control of the qubit state produces a time-dependent change in the frequency of the light field. An appropriately timed sequence of sudden frequency changes reduces the quantum noise fluctuations in one quadrature of the field well below the standard quantum limit. The degree of squeezing and the time of generation are directly controlled by the number of frequency shifts applied. Even in the presence of realistic noise and imperfections, our protocol promises to be capable of generating a useful degree of squeezing with present experimental capabilities. PMID:28358025

  13. Strong-Field Induced Dissociative Ionization of Vinyl Bromide Probed by Femtosecond Extreme Ultraviolet (xuv) Transient Absorption Spectroscopy

    NASA Astrophysics Data System (ADS)

    Lin, Ming-Fu; Neumark, Daniel; Leone, Stephen R.; Gessner, Oliver

    2014-06-01

    A table-top high harmonic XUV light source (50 eV to 70 eV) has been successfully utilized to explore the ultrafast dynamics of vinyl bromide (CH2=CHBr) with electronic state specificity and elemental sensitivity. Strong-field ionization (SFI) provides a method to produce ions in different ionic states. The production and dissociation dynamics of these ionic states are investigated by femtosecond XUV transient absorption spectroscopy. The XUV photons probe the time-dependent spectroscopic features associated with transitions of the Br (3d) inner-shell electrons to vacancies in molecular and atomic valence orbitals. The experimental observation shows that two ionic states are produced by SFI. The first ionic excited state is dissociative, leading to C-Br bond dissociation which is observed in real time as a shift in the absorption energy. The results offer powerful new insights about orbital-specific electronic processes in high field ionization, coupled vibrational relaxation and dissociation dynamics, and the correlation of valence hole-state location and dissociation in polyatomic molecules, all probed simultaneously by ultrafast table-top XUV spectroscopy.

  14. Seismically induced rock slope failures resulting from topographic amplification of strong ground motions: The case of Pacoima Canyon, California

    USGS Publications Warehouse

    Sepulveda, S.A.; Murphy, W.; Jibson, R.W.; Petley, D.N.

    2005-01-01

    The 1994 Northridge earthquake (Mw = 6.7) triggered extensive rock slope failures in Pacoima Canyon, immediately north of Los Angeles, California. Pacoima Canyon is a narrow and steep canyon incised in gneissic and granitic rocks. Peak accelerations of nearly 1.6 g were recorded at a ridge that forms the left abutment of Pacoima Dam; peak accelerations at the bottom of the canyon were less than 0.5 g, suggesting the occurrence of topographic amplification. Topographic effects have been previously suggested to explain similarly high ground motions at the site during the 1971 (Mw = 6.7) San Fernando earthquake. Furthermore, high landslide concentrations observed in the area have been attributed to unusually strong ground motions rather than higher susceptibility to sliding compared with nearby zones. We conducted field investigations and slope stability back-analyses to confirm the impact of topographic amplification on the triggering of landslides during the 1994 earthquake. Our results suggest that the observed extensive rock sliding and falling would have not been possible under unamplified seismic conditions, which would have generated a significantly lower number of areas affected by landslides. In contrast, modelling slope stability using amplified ground shaking predicts slope failure distributions matching what occurred in 1994. This observation confirms a significant role for topographic amplification on the triggering of landslides at the site, and emphasises the need to select carefully the inputs for seismic slope stability analyses. ?? 2005 Elsevier B.V. All rights reserved.

  15. Strong protection against ricin challenge induced by a novel modified ricin A-chain protein in mouse model.

    PubMed

    Zhang, Tao; Yang, Hao; Kang, Lin; Gao, Shan; Xin, Wenwen; Yao, Wenwu; Zhuang, Xiangjin; Ji, Bin; Wang, Jinglin

    2015-01-01

    Ricin toxin (RT) is an extremely potent toxin derived from the castor bean plant. As a possible bioterrorist weapon, it was categorized as a level B agent in international society. With the growing awareness and concerns of the "white powder incident" in recent years, it is indispensable to develop an effective countermeasure against RT intoxication. In this study we used site-directed mutagenesis and polymerase chain reaction (PCR) techniques to modify the gene of ricin A-chain (RTA). As a result, we have generated a mutated and truncated ricin A-chain (mtRTA) vaccine antigen by E.coli strain. The cytotoxicity assay was used to evaluate the safety of the as-prepared mtRTA antigen, and the results showed that there was no residual toxicity observed when compared to the recombinant RTA (rRTA) or native RT. Furthermore, BALB/c mice were subcutaneously (s.c.) vaccinated with mtRTA 3 times at an interval of 2 weeks, and then the survivals were evaluated after intraperitoneal (i.p.) or intratracheal challenge of RT. The vaccinated mice developed a strong protective immune response that was wholly protective against 40 × LD50 of RT i.p. injection or 20 × LD50 of RT intratracheal spraying. The mtRTA antigen has great potential to be a vaccine candidate for future application in humans.

  16. Sodium dodecyl sulphate, a strong inducer of thermostable glucanhydrolase secretion from a derepressed mutant strain of Bacillus alcalophilus GCBNA-4.

    PubMed

    Shamim, Nadia; Ali, Sikander; Ul-Haq, Ikram

    2013-04-01

    In the present study, we report the optimisation of batch conditions for improved α-1,4-glucan-glucanohydrolase (GGH) secretion by a nitrous acid (NA)-treated Bacillus alcalophilus. The wild (isolate GCB-18) and NA-derivative (mutant GCBNA-4) were grown in a medium containing 10 g/L nutrient broth, 10 g/L starch, 5 g/L lactose, 2 g/L ammonium sulphate, 2 g/L CaCl2 and phosphate buffer (pH 7.6). Sodium dodecyl sulphate (SDS) was used as an enzyme inducer while batch fermentations were carried out at 40 °C. The mutant produced GGH in 40 h which was 15-fold higher than the wild in presence of SDS. Thermodynamic studies revealed that the mutant culture exhibited the capability for improved enzyme activity over a broad range of temperature (35-70 °C). The enzyme was purified by cation-exchange column chromatography with ~80 % recovery. The performance of fuzzy-logic system control was found to be highly promising for the improved substrate conversion rate. The correlation (1.045E + 0025) among variables demonstrated the model terms as highly significant indicating commercial utility of the culture used (P < 0.05).

  17. Targeting of the activation-induced cytosine deaminase is strongly influenced by the sequence and structure of the targeted DNA.

    PubMed

    Shen, Hong Ming; Ratnam, Sarayu; Storb, Ursula

    2005-12-01

    Activation-induced deaminase (AID) initiates immunoglobulin somatic hypermutation (SHM). Since in vitro AID was shown to deaminate cytosines on single-stranded DNA or the nontranscribed strand, it remained a puzzle how in vivo AID targets both DNA strands equally. Here we investigate the roles of transcription and DNA sequence in cytosine deamination. Strikingly different results are found with different substrates. Depending on the target sequence, the transcribed DNA strand is targeted as well as or better than the nontranscribed strand. The preferential targeting is not related to the frequency of AID hot spots. Comparison of cytosine deamination by AID and bisulfite shows different targeting patterns suggesting that AID may locally unwind the DNA. We conclude that somatic hypermutation on both DNA strands is the natural outcome of AID action on a transcribed gene; furthermore, the DNA sequence or structure and topology play major roles in targeting AID in vitro and in vivo. On the other hand, the lack of mutations in the first approximately 100 nucleotides and beyond about 1 to 2 kb from the promoter of immunoglobulin genes during SHM must be due to special conditions of transcription and chromatin in vivo.

  18. Chemical properties of lipids strongly affect the kinetics of the membrane-induced aggregation of α-synuclein

    PubMed Central

    Brown, James W. P.; Ouberai, Myriam M.; Flagmeier, Patrick; Vendruscolo, Michele; Buell, Alexander K.; Sparr, Emma; Dobson, Christopher M.

    2016-01-01

    Intracellular α-synuclein deposits, known as Lewy bodies, have been linked to a range of neurodegenerative disorders, including Parkinson’s disease. α-Synuclein binds to synthetic and biological lipids, and this interaction has been shown to play a crucial role for both α-synuclein’s native function, including synaptic plasticity, and the initiation of its aggregation. Here, we describe the interplay between the lipid properties and the lipid binding and aggregation propensity of α-synuclein. In particular, we have observed that the binding of α-synuclein to model membranes is much stronger when the latter is in the fluid rather than the gel phase, and that this binding induces a segregation of the lipids into protein-poor and protein-rich populations. In addition, α-synuclein was found to aggregate at detectable rates only when interacting with membranes composed of the most soluble lipids investigated here. Overall, our results show that the chemical properties of lipids determine whether or not the lipids can trigger the aggregation of α-synuclein, thus affecting the balance between functional and aberrant behavior of the protein. PMID:27298346

  19. Regulatory T cells are strong promoters of acute ischemic stroke in mice by inducing dysfunction of the cerebral microvasculature.

    PubMed

    Kleinschnitz, Christoph; Kraft, Peter; Dreykluft, Angela; Hagedorn, Ina; Göbel, Kerstin; Schuhmann, Michael K; Langhauser, Friederike; Helluy, Xavier; Schwarz, Tobias; Bittner, Stefan; Mayer, Christian T; Brede, Marc; Varallyay, Csanad; Pham, Mirko; Bendszus, Martin; Jakob, Peter; Magnus, Tim; Meuth, Sven G; Iwakura, Yoichiro; Zernecke, Alma; Sparwasser, Tim; Nieswandt, Bernhard; Stoll, Guido; Wiendl, Heinz

    2013-01-24

    We have recently identified T cells as important mediators of ischemic brain damage, but the contribution of the different T-cell subsets is unclear. Forkhead box P3 (FoxP3)-positive regulatory T cells (Tregs) are generally regarded as prototypic anti-inflammatory cells that maintain immune tolerance and counteract tissue damage in a variety of immune-mediated disorders. In the present study, we examined the role of Tregs after experimental brain ischemia/reperfusion injury. Selective depletion of Tregs in the DEREG mouse model dramatically reduced infarct size and improved neurologic function 24 hours after stroke and this protective effect was preserved at later stages of infarct development. The specificity of this detrimental Treg effect was confirmed by adoptive transfer experiments in wild-type mice and in Rag1(-/-) mice lacking lymphocytes. Mechanistically, Tregs induced microvascular dysfunction in vivo by increased interaction with the ischemic brain endothelium via the LFA-1/ICAM-1 pathway and platelets and these findings were confirmed in vitro. Ablation of Tregs reduced microvascular thrombus formation and improved cerebral reperfusion on stroke, as revealed by ultra-high-field magnetic resonance imaging at 17.6 Tesla. In contrast, established immunoregulatory characteristics of Tregs had no functional relevance. We define herein a novel and unexpected role of Tregs in a primary nonimmunologic disease state.

  20. EB 1089, a novel vitamin D analog with strong antiproliferative and differentiation-inducing effects on target cells.

    PubMed

    Hansen, C M; Mäenpää, P H

    1997-12-01

    The physiologically active form of vitamin D, 1alpha,25-dihydroxyvitamin D3, plays an important role not only in the establishment and maintenance of calcium metabolism, but also in regulating cell growth and differentiation. As the clinical usefulness of 1alpha,25-dihydroxyvitamin D3 is limited by its tendency to cause hypercalcemia, new analogs with a better therapeutic profile have been synthesized. One of these new synthetic vitamin D analogs is EB 1089, which is characterized by an altered side chain structure featuring 26,27-dimethyl groups and two double bonds. This analog has been shown to be more potent than 1,25-dihydroxyvitamin D3 in inhibiting proliferation, stimulating differentiation, and inducing apoptosis in a number of different cell types, including cancer cells. Despite being more potent than 1alpha,25-dihydroxyvitamin D3 with respect to its cell regulatory effects, EB 1089 displays weaker calcemic side-effects. These characteristics make EB 1089 a potentially useful compound for the treatment of a diversity of clinical disorders, including cancer and metabolic bone diseases. A promising phase I study with EB 1089 in patients with advanced breast and colon cancer has already been carried out, and more clinical trials evaluating the clinical effectiveness of EB 1089 in other types of cancer are in progress.

  1. Coherent phenomena in terahertz 2D plasmonic structures: strong coupling, plasmonic crystals, and induced transparency by coupling of localized modes

    NASA Astrophysics Data System (ADS)

    Dyer, Gregory C.; Aizin, Gregory R.; Allen, S. James; Grine, Albert D.; Bethke, Don; Reno, John L.; Shaner, Eric A.

    2014-05-01

    The device applications of plasmonic systems such as graphene and two dimensional electron gases (2DEGs) in III-V heterostructures include terahertz detectors, mixers, oscillators and modulators. These two dimensional (2D) plasmonic systems are not only well-suited for device integration, but also enable the broad tunability of underdamped plasma excitations via an applied electric field. We present demonstrations of the coherent coupling of multiple voltage tuned GaAs/AlGaAs 2D plasmonic resonators under terahertz irradiation. By utilizing a plasmonic homodyne mixing mechanism to downconvert the near field of plasma waves to a DC signal, we directly detect the spectrum of coupled plasmonic micro-resonator structures at cryogenic temperatures. The 2DEG in the studied devices can be interpreted as a plasmonic waveguide where multiple gate terminals control the 2DEG kinetic inductance. When the gate tuning of the 2DEG is spatially periodic, a one-dimensional finite plasmonic crystal forms. This results in a subwavelength structure, much like a metamaterial element, that nonetheless Bragg scatters plasma waves from a repeated crystal unit cell. A 50% in situ tuning of the plasmonic crystal band edges is observed. By introducing gate-controlled defects or simply terminating the lattice, localized states arise in the plasmonic crystal. Inherent asymmetries at the finite crystal boundaries produce an induced transparency-like phenomenon due to the coupling of defect modes and crystal surface states known as Tamm states. The demonstrated active control of coupled plasmonic resonators opens previously unexplored avenues for sensitive direct and heterodyne THz detection, planar metamaterials, and slow-light devices.

  2. Experimental observation of beta-induced Alfvén eigenmodes during strong tearing modes on the EAST tokamak in fast-electron plasmas

    NASA Astrophysics Data System (ADS)

    Xu, M.; Chen, W.; Hu, L. Q.; Zhou, R. J.; Zhong, G. Q.; Shi, T. H.; Xu, L. Q.; Zhang, Y.; Sun, Y. W.; Lin, S. Y.; Shen, B.; the EAST Team

    2013-06-01

    Beta-induced Alfvén eigenmodes (BAEs) during strong tearing modes are investigated on the EAST tokamak systematically, and the relation between the BAE frequencies and plasma parameters such as electron density \\bar{n}_e , ion temperature Ti, the profile of safety factor q(ρ) or the intensity of \\dot{B}_\\theta (the width of the magnetic island w) is given in detail during the injection of the power of lower hybrid wave (LHW) (or is also accompanied by the injection of ion cyclotron resonance frequency) comprehensively. All the conditions show that the values of BAE frequencies f_BAE \\propto (T_\\rme + \\frac{7}{4} T_\\rmi)^{1/2} are in agreement with the generalized fishbone-like dispersion relation, and the activities of the BAEs have a strong interaction with the process of magnetic reconnection. The BAEs are formed during the injection of the power of LHW, and disappear immediately when the power of LHW is turned off on the EAST tokamak. The LHW plasmas or the runaway discharge in Ohmic plasmas can increase the population of fast electrons, which plays a role in the activities of BAEs and a possible excitation mechanism for the BAEs during the strong tearing mode activities.

  3. A multi-subunit Chlamydia vaccine inducing neutralizing antibodies and strong IFN-γ⁺ CMI responses protects against a genital infection in minipigs.

    PubMed

    Bøje, Sarah; Olsen, Anja Weinreich; Erneholm, Karin; Agerholm, Jørgen Steen; Jungersen, Gregers; Andersen, Peter; Follmann, Frank

    2016-02-01

    Chlamydia is the most widespread sexually transmitted bacterial disease and a prophylactic vaccine is highly needed. Ideally, this vaccine is required to induce a combined response of Th1 cell-mediated immune (CMI) response in concert with neutralizing antibodies. Using a novel Göttingen minipig animal model, we evaluated the immunogenicity and efficacy of a multi-subunit vaccine formulated in the strong Th1-inducing adjuvant CAF01. We evaluated a mixture of two fusion proteins (Hirep1 and CTH93) designed to promote either neutralizing antibodies or cell-mediated immunity, respectively. Hirep1 is a novel immunogen based on the variant domain (VD) 4 region from major outer membrane protein (MOMP) serovar (Sv) D, SvE and SvF, and CTH93 is a fusion molecule of three antigens (CT043, CT414 and MOMP). Pigs were immunized twice intramuscularly with either Hirep1+CTH93/CAF01, UV-inactivated Chlamydia trachomatis SvD bacteria (UV-SvD/CAF01) or CAF01. The Hirep1+CTH93/CAF01 vaccine induced a strong CMI response against the vaccine antigens and high titers of antibodies, particularly against the VD4 region of MOMP. Sera from Hirep1+CTH93/CAF01 immunized pigs neutralized C. trachomatis SvD and SvF infectivity in vitro. Both Hirep1+CTH93/CAF01 and UV-SvD/CAF01 vaccination protected pigs against a vaginal C. trachomatis SvD infection. In conclusion, the Hirep1+CTH93/CAF01 vaccine proved highly immunogenic and equally protective as UV-SvD/CAF01 showing promise for the development of a subunit vaccine against Chlamydia.

  4. Oral Combination Vaccine, Comprising Bifidobacterium Displaying Hepatitis C Virus Nonstructural Protein 3 and Interferon-α, Induces Strong Cellular Immunity Specific to Nonstructural Protein 3 in Mice.

    PubMed

    Kitagawa, Koichi; Omoto, Chika; Oda, Tsugumi; Araki, Ayame; Saito, Hiroki; Shigemura, Katsumi; Katayama, Takane; Hotta, Hak; Shirakawa, Toshiro

    2017-01-23

    We previously generated an oral hepatitis C virus (HCV) vaccine using Bifidobacterium displaying the HCV nonstructural protein 3 (NS3) polypeptide. NS3-specific cellular immunity is important for viral clearance and recovery from HCV infection. In this study, we enhanced the cellular immune responses induced by our oral HCV vaccine, Bifidobacterium longum 2165 (B. longum 2165), by combining interferon-α (IFN-α) as an adjuvant with the vaccine in a mouse experimental model. IFN-α is a widely used cytokine meeting the standard of care (SOC) for HCV infection and plays various immunoregulatory roles. We treated C57BL/6N mice with B. longum 2165 every other day and/or IFN-α twice a week for a month and then analyzed the immune responses using spleen cells. We determined the induction of NS3-specific cellular immunity by cytokine quantification, intracellular cytokine staining, and a cytotoxic T lymphocyte (CTL) assay targeting EL4 tumor cells expressing NS3/4A protein (EL4-NS3/4A). We also treated mice bearing EL4-NS3/4A tumor with the combination therapy in vivo. The results confirmed that the combination therapy of B. longum 2165 and IFN-α induced significantly higher IFN-γ secretion, higher population of CD4(+)T and CD8(+)T cells secreting IFN-γ, and higher CTL activity against EL4-NS3/4A cells compared with the control groups of phosphate-buffered saline, B. longum 2165 alone, and IFN-α alone (p < 0.05). We also confirmed that the combination therapy strongly enhanced tumor growth inhibitory effects in vivo with no serious adverse effects (p < 0.05). These results suggest that the combination of B. longum 2165 and IFN-α could induce a strong cellular immunity specific to NS3 protein as a combination therapy augmenting the current SOC immunotherapy against chronic HCV infection.

  5. Strong induced polarity between Poly(vinylidene fluoride-co-chlorotrifluoroethylene) and α-SiC and its influence on dielectric permittivity and loss of their composites

    SciTech Connect

    Feng, Yefeng; Gong, Honghong; Xie, Yunchuan; Zhang, Zhicheng; Wei, Xiaoyong; Yang, Lanjun

    2015-03-07

    Interface polarization and interface zone have been widely utilized to account for the abnormally improved dielectric properties of composites although their formation is rather vague and their influence has never been directly measured. In this work, micro α-SiC was designed as the filler particles incorporated into poly(vinylidenefluoride-co-chlorotrifluoroethylene) with internal double bonds (P(VDF-CTFE-DB)) to construct polymer micro composites through solution casting method. The dielectric constant of the composites is found to be increasing linearly as SiC content increases at lower content and the highest value is obtained as 83 at 100 Hz, which is unusually higher than both pristine polymer (13@100 Hz) and SiC filler (17@100 Hz). By studying the dielectric properties of a bilayer model composite, the real dielectric permittivity of SiC sheet and P(VDF-CTFE-DB) layer has been directly measured to be significantly enhanced than their original value. The induced polarity between high polar PVDF units in polymer matrix and the electron-hole dipoles in α-SiC is responsible for the elevated dielectric properties of both components, which could address the failure of binary series and parallel models in predicting the dielectric permittivity of 0-3 composites as well. The strong dependence of induced polarity on the volume content, thickness, and polar nature of both components strongly suggests establishing promising high induced polarity between polymer matrix and fillers may provide an alternative strategy for fabricating high-k composites.

  6. CHARACTERIZATION OF NICOTINE ACETYLCHOLINE RECEPTOR SUBUNITS IN THE COCKROACH Periplaneta americana MUSHROOM BODIES REVEALS A STRONG EXPRESSION OF β1 SUBUNIT: INVOLVEMENT IN NICOTINE-INDUCED CURRENTS.

    PubMed

    Taillebois, Emiliane; Thany, Steeve H

    2016-09-01

    Nicotinic acetylcholine receptors are ligand-gated ion channels expressed in many insect structures, such as mushroom bodies, in which they play a central role. We have recently demonstrated using electrophysiological recordings that different native nicotinic receptors are expressed in cockroach mushroom bodies Kenyon cells. In the present study, we demonstrated that eight genes coding for cockroach nicotinic acetylcholine receptor subunits are expressed in the mushroom bodies. Quantitative real-time polymerase chain reaction (PCR) experiments demonstrated that β1 subunit was the most expressed in the mushroom bodies. Moreover, antisense oligonucleotides performed against β1 subunit revealed that inhibition of β1 expression strongly decreases nicotine-induced currents amplitudes. Moreover, co-application with 0.5 μM α-bungarotoxin completely inhibited nicotine currents whereas 10 μM d-tubocurarine had a partial effect demonstrating that β1-containing neuronal nicotinic acetylcholine receptor subtypes could be sensitive to the nicotinic acetylcholine receptor antagonist α-bungarotoxin.

  7. The characterization of six auxin-induced tomato GH3 genes uncovers a member, SlGH3.4, strongly responsive to arbuscular mycorrhizal symbiosis.

    PubMed

    Liao, Dehua; Chen, Xiao; Chen, Aiqun; Wang, Huimin; Liu, Jianjian; Liu, Junli; Gu, Mian; Sun, Shubin; Xu, Guohua

    2015-04-01

    In plants, the GH3 gene family is widely considered to be involved in a broad range of plant physiological processes, through modulation of hormonal homeostasis. Multiple GH3 genes have been functionally characterized in several plant species; however, to date, limited works to study the GH3 genes in tomato have been reported. Here, we characterize the expression and regulatory profiles of six tomato GH3 genes, SlGH3.2, SlGH3.3, SlGH3.4, SlGH3.7, SlGH3.9 and SlGH3.15, in response to different phytohormone applications and arbuscular mycorrhizal (AM) fungal colonization. All six GH3 genes showed inducible responses to external IAA, and three members were significantly up-regulated in response to AM symbiosis. In particular, SlGH3.4, the transcripts of which were barely detectable under normal growth conditions, was strongly activated in the IAA-treated and AM fungal-colonized roots. A comparison of the SlGH3.4 expression in wild-type plants and M161, a mutant with a defect in AM symbiosis, confirmed that SlGH3.4 expression is highly correlated to mycorrhizal colonization. Histochemical staining demonstrated that a 2,258 bp SlGH3.4 promoter fragment could drive β-glucuronidase (GUS) expression strongly in root tips, steles and cortical cells of IAA-treated roots, but predominantly in the fungal-colonized cells of mycorrhizal roots. A truncated 654 bp promoter failed to direct GUS expression in IAA-treated roots, but maintained the symbiosis-induced activity in mycorrhizal roots. In summary, our results suggest that a mycorrhizal signaling pathway that is at least partially independent of the auxin signaling pathway has evolved for the co-regulation of the auxin- and mycorrhiza-activated GH3 genes in plants.

  8. Distribution characteristics of earthquake-induced landslide with the earthquake source fault-the cases of recent strong earthquakes in eastern Japan

    NASA Astrophysics Data System (ADS)

    Hasi, B.; Ishii, Y.; Maruyama, K.; Terada, H.

    2009-12-01

    In recent years, 3 strong earthquakes, the Mid-Niigata earthquake (M6.8, October 23, 2004), the Noto Peninsula earthquake (M6.9, March 25, 2007), the Chuetsu-offshore earthquake (M6.8, July 16, 2007), stroke eastern Japan. All of these earthquakes occurred inland by reverse fault, with depth 11-17km hypocenter, triggered a large number of landslides and caused serious damage to the involved regions due to these landslides. To clarify the distribution characteristics of landslides induced by these earthquakes, we interpreted landslides by using aerial photographs taken immediately after the earthquakes, and analyzed landslide distributions with the peak ground acceleration (PGA) and seismic intensity (in Japan Meteorological Agency intensity scale), source fault of the mainshock of each earthquake. The analyzing results revealed that: 1) Most of the landslides occurred in the area where the PGA is larger than 500 gal, and the maximum seismic intensity is larger than 5 plus ; 2) The landslides occurred in a short distance from the source fault (the shortest distance from the surface projection of top tip of the fault), about 80% occurred within the distance of 20 km; 3) More than 80% of landslides occurred on the hanging wall, and the size of landslide (length, width, area) is larger than that occurred on the footwall of the source fault; 4) The number and size of landslide tends to deceases with the distance from the source fault. Our results suggesting that the distance from the source fault of earthquake could be a parameter to analyze the landslide occurrence induce by strong earthquake.

  9. The response of short-scale density fluctuations to the activity of beta-induced Alfvén eigenmodes during strong tearing modes on EAST tokamak

    NASA Astrophysics Data System (ADS)

    Cao, G. M.; Li, Y. D.; Li, Q.; Sun, P. J.; Wu, G. J.; Hu, L. Q.; the EAST Team

    2015-08-01

    Beta-induced Alfvén eigenmodes (BAEs) during strong tearing modes (TMs) have been frequently observed in fast-electron plasmas of EAST tokamak. The dynamics of the short-scale ({k}\\perp {ρ }s~{1.5-4.3}) density fluctuations during the activity of BAEs with strong TMs has been preliminarily investigated by a tangential CO2 laser collective scattering system. The results suggest the active, but different, response of short-scale density fluctuations to the TMs and BAEs. In the low-frequency (0-10 kHz) part of density fluctuations, there are harmonic oscillations totally corresponding to those of TMs. In the medium-high frequency (10-250 kHz) part of density fluctuations, with the appearance of the BAEs, the medium-high frequency density fluctuations begin to be dominated by several quasi-coherent (QC) modes, and the frequencies of the QC modes seem to be related to the changes of both TMs and BAEs. These results would shed some light on the understanding of the multi-scale interaction physics.

  10. Strongly-motivated positive affects induce faster responses to local than global information of visual stimuli: an approach using large-size Navon letters.

    PubMed

    Noguchi, Yasuki; Tomoike, Kouta

    2016-01-12

    Recent studies argue that strongly-motivated positive emotions (e.g. desire) narrow a scope of attention. This argument is mainly based on an observation that, while humans normally respond faster to global than local information of a visual stimulus (global advantage), positive affects eliminated the global advantage by selectively speeding responses to local (but not global) information. In other words, narrowing of attentional scope was indirectly evidenced by the elimination of global advantage (the same speed of processing between global and local information). No study has directly shown that strongly-motivated positive affects induce faster responses to local than global information while excluding a bias for global information (global advantage) in a baseline (emotionally-neutral) condition. In the present study, we addressed this issue by eliminating the global advantage in a baseline (neutral) state. Induction of positive affects under this state resulted in faster responses to local than global information. Our results provided direct evidence that positive affects in high motivational intensity narrow a scope of attention.

  11. Diet-Induced Metabolic Improvements in a Hamster Model of Hypercholesterolemia Are Strongly Linked to Alterations of the Gut Microbiota▿ †

    PubMed Central

    Martínez, Inés; Wallace, Grant; Zhang, Chaomei; Legge, Ryan; Benson, Andrew K.; Carr, Timothy P.; Moriyama, Etsuko N.; Walter, Jens

    2009-01-01

    The mammalian gastrointestinal microbiota exerts a strong influence on host lipid and cholesterol metabolism. In this study, we have characterized the interplay among diet, gut microbial ecology, and cholesterol metabolism in a hamster model of hypercholesterolemia. Previous work in this model had shown that grain sorghum lipid extract (GSL) included in the diet significantly improved the high-density lipoprotein (HDL)/non-HDL cholesterol equilibrium (T. P. Carr, C. L. Weller, V. L. Schlegel, S. L. Cuppett, D. M. Guderian, Jr., and K. R. Johnson, J. Nutr. 135:2236-2240, 2005). Molecular analysis of the hamsters' fecal bacterial populations by pyrosequencing of 16S rRNA tags, PCR-denaturing gradient gel electrophoresis, and Bifidobacterium-specific quantitative real-time PCR revealed that the improvements in cholesterol homeostasis induced through feeding the hamsters GSL were strongly associated with alterations of the gut microbiota. Bifidobacteria, which significantly increased in abundance in hamsters fed GSL, showed a strong positive association with HDL plasma cholesterol levels (r = 0.75; P = 0.001). The proportion of members of the family Coriobacteriaceae decreased when the hamsters were fed GSL and showed a high positive association with non-HDL plasma cholesterol levels (r = 0.84; P = 0.0002). These correlations were more significant than those between daily GSL intake and animal metabolic markers, implying that the dietary effects on host cholesterol metabolism are conferred, at least in part, through an effect on the gut microbiota. This study provides evidence that modulation of the gut microbiota-host metabolic interrelationship by dietary intervention has the potential to improve mammalian cholesterol homeostasis, which has relevance for cardiovascular health. PMID:19411417

  12. Antibiotics, arsenate and H2O2 induce the promoter of Staphylococcus aureus cspC gene more strongly than cold.

    PubMed

    Chanda, Palas Kumar; Mondal, Rajkrishna; Sau, Keya; Sau, Subrata

    2009-04-01

    Proteins expressed by the bacterial cold shock genes are highly conserved at sequence level and perform various biological functions in both the cold-stressed and normal cells. To study the effects of various agents on the cold shock genes of Staphylococcus aureus, we have cloned the upstream region of cspC from S. aureus Newman and found that the above region possesses appreciable promoter (P(c)) activity even at 37 degrees C. A reporter S. aureus strain CHANDA2, constructed by inserting the P(c)-lacZ transcriptional fusion into S. aureus RN4220 genome, was found to express very low level of beta-galactosidase after cold shock, indicating that low temperature induces P(c) very weakly. Interestingly, transcription from P(c ) was induced very strongly by several antibiotics, hydrogen peroxide and arsenate salt. Cold shock proteins expressed by S. aureus are highly identical at sequence level and bear single-strand nucleic acid binding motifs. A 16 nt downstream box and a 13 nt upstream box were identified at the downstream of initiation codon and at the upstream of ribosome binding site of csp transcripts. Their roles in S. aureus cold shock gene expression have been discussed elaborately.

  13. Mucin-depleted foci show strong activation of inflammatory markers in 1,2-dimethylhydrazine-induced carcinogenesis and are promoted by the inflammatory agent sodium dextran sulfate.

    PubMed

    Femia, Angelo Pietro; Dolara, Piero; Luceri, Cristina; Salvadori, Maddalena; Caderni, Giovanna

    2009-08-01

    Mucin-depleted foci (MDF), formed by dysplastic crypts devoid of mucins, have been identified in the colon of carcinogen-treated rodents and in humans at high risk for colon cancer. The lack of the protective layer of mucus may cause inflammation which has been linked to colon carcinogenesis, therefore, the expression of markers such as cyclooxygenase-2 (COX-2), inducible nitric oxide synthase (i-NOS) and macrophage infiltration was studied with immunohistochemistry (IH) in MDF harvested from F344 rats treated with the colon carcinogen 1,2-dimethylhydrazine (DMH). The same determinations were performed in aberrant crypt foci (ACF) and, at a later time point, in tumours. A dramatic increase in COX-2, i-NOS and macrophage infiltration was observed in MDF but ACF showed a moderate increase compared with the paired normal mucosa. Tumours were positive for all the markers. RT-PCR experiments demonstrated that i-NOS RNA expression was increased in a set of MDF confirming the results obtained with immunohistochemistry. In an inflammation-cancer experimental model [mice treated with azoxymethane (AOM) and dextran sodium sulphate (DSS)], we observed that DSS-induced inflammation promoted MDF in a dose-dependent manner, whereas ACF were not affected. In conclusion, we report here for the first time a strong activation of the inflammatory process in MDF, which may contribute to the further progression of MDF to tumours.

  14. DNA vaccine encoding type IV pilin of Actinobacillus pleuropneumoniae induces strong immune response but confers limited protective efficacy against serotype 2 challenge.

    PubMed

    Lu, Yu-Chun; Li, Min-Chen; Chen, Yi-Min; Chu, Chun-Yen; Lin, Shuen-Fuh; Yang, Wen-Jen

    2011-10-13

    Actinobacillus pleuropneumoniae is a gram-negative bacterial pathogen that causes swine pleuropneumonia, a highly contagious and often fatal disease that occurs worldwide. Our previous study showed that DNA vaccines encoding Apx exotoxin structural proteins ApxIA and/or ApxIIA, are a promising novel approach for immunization against the lethal challenge of A. pleuropneumoniae serotype 1. Vaccination against A. pleuropneumoniae is impeded by the lack of vaccines inducing reliable cross-serotype protection. Type IV fimbrial protein ApfA has been shown to be present and highly conserved in various serotypes of A. pleuropneumoniae. A novel DNA vaccine encoding ApfA (pcDNA-apfA) was constructed to evaluate the protective efficacy against infection with A. pleuropneumoniae serotype 2. A significant antibody response against pilin was generated following pcDNA-apfA immunization, suggesting that it was expressed in vivo. The IgG subclass (IgG1 and IgG2a) analysis indicates that the pcDNA-apfA vaccine induces both Th1 and Th2 immune responses. The IgA analysis shows that mucosal immunity could be enhanced by this DNA vaccine. Nevertheless, the strong antibody response induced by pcDNA-apfA vaccine only provided limited 30% protective efficacy against the serotype 2 challenge. These results in this study do not coincide with that the utility of type IV pilin is a good vaccine candidate against other infectious pathogens. It indicates that pilin should play a limited role in the development of a vaccine against A. pleuropneumoniae infection.

  15. Strong ground motion generated by controlled blasting experiments and mining induced seismic events recorded underground at deep level mines in South Africa

    NASA Astrophysics Data System (ADS)

    Milev, A.; Selllers, E.; Skorpen, L.; Scheepers, L.; Murphy, S.; Spottiswoode, S. M.

    2011-12-01

    A number of simulated rockbursts were conducted underground at deep level gold mines in South Africa in order to estimate the rock mass response when subjected to strong ground motion. The rockbursts were simulated by means of large blasts detonated in solid rock close to the sidewall of a tunnel. The simulated rockbursts involved the design of the seismic source, seismic observations in the near and far field, high-speed video filming, a study of rock mass conditions such as fractures, joints, rock strength etc. Knowledge of the site conditions before and after the simulated rockbursts was also gained. The numerical models used in the design of the simulated rockbursts were calibrated by small blasts taking place at each experimental site. A dense array of shock type accelerometers was installed along the blasting wall to monitor the attenuation of the strong ground motion as a function of the distance from the source. The attenuation of peak particle velocities, was found to be proportional to R^-1.7. Special investigations were carried out to evaluate the mechanism and the magnitude of damage, as well as the support behaviour under excessive dynamic loading. The strong ground motion generated by mining induced seismic events was studied, as part of this work, not only to characterize the rock mass response, but also to estimate the site effect on the surface of the underground excavations. A stand-alone instrument especially designed for recording strong ground motions was used to create a large database of peak particle velocities measured on stope hangingwalls. A total number of 58 sites located in stopes where the Carbon Leader Reef, Ventersdorp Contact Reef, Vaal Reef and Basal Reef are mined, were monitored. The peak particle velocities were measured at the surface of the excavations to identify the effect of the free surface and the fractures surrounding the underground mining. Based on these measurements the generally accepted velocity criterion of 3 m

  16. Elongation Factor Tu and Heat Shock Protein 70 Are Membrane-Associated Proteins from Mycoplasma ovipneumoniae Capable of Inducing Strong Immune Response in Mice

    PubMed Central

    Jiang, Fei; He, Jinyan; Navarro-Alvarez, Nalu; Xu, Jian; Li, Xia; Li, Peng; Wu, Wenxue

    2016-01-01

    Chronic non-progressive pneumonia, a disease that has become a worldwide epidemic has caused considerable loss to sheep industry. Mycoplasma ovipneumoniae (M. ovipneumoniae) is the causative agent of interstitial pneumonia in sheep, goat and bighorn. We here have identified by immunogold and immunoblotting that elongation factor Tu (EF-Tu) and heat shock protein 70 (HSP 70) are membrane-associated proteins on M. ovipneumonaiea. We have evaluated the humoral and cellular immune responses in vivo by immunizing BALB/c mice with both purified recombinant proteins rEF-Tu and rHSP70. The sera of both rEF-Tu and rHSP70 treated BALB/c mice demonstrated increased levels of IgG, IFN-γ, TNF-α, IL-12(p70), IL-4, IL-5 and IL-6. In addition, ELISPOT assay showed significant increase in IFN-γ+ secreting lymphocytes in the rHSP70 group when compared to other groups. Collectively our study reveals that rHSP70 induces a significantly better cellular immune response in mice, and may act as a Th1 cytokine-like adjuvant in immune response induction. Finally, growth inhibition test (GIT) of M. ovipneumoniae strain Y98 showed that sera from rHSP70 or rEF-Tu-immunized mice inhibited in vitro growth of M. ovipneumoniae. Our data strongly suggest that EF-Tu and HSP70 of M. ovipneumoniae are membrane-associated proteins capable of inducing antibody production, and cytokine secretion. Therefore, these two proteins may be potential candidates for vaccine development against M. ovipneumoniae infection in sheep. PMID:27537186

  17. Elongation Factor Tu and Heat Shock Protein 70 Are Membrane-Associated Proteins from Mycoplasma ovipneumoniae Capable of Inducing Strong Immune Response in Mice.

    PubMed

    Jiang, Fei; He, Jinyan; Navarro-Alvarez, Nalu; Xu, Jian; Li, Xia; Li, Peng; Wu, Wenxue

    2016-01-01

    Chronic non-progressive pneumonia, a disease that has become a worldwide epidemic has caused considerable loss to sheep industry. Mycoplasma ovipneumoniae (M. ovipneumoniae) is the causative agent of interstitial pneumonia in sheep, goat and bighorn. We here have identified by immunogold and immunoblotting that elongation factor Tu (EF-Tu) and heat shock protein 70 (HSP 70) are membrane-associated proteins on M. ovipneumonaiea. We have evaluated the humoral and cellular immune responses in vivo by immunizing BALB/c mice with both purified recombinant proteins rEF-Tu and rHSP70. The sera of both rEF-Tu and rHSP70 treated BALB/c mice demonstrated increased levels of IgG, IFN-γ, TNF-α, IL-12(p70), IL-4, IL-5 and IL-6. In addition, ELISPOT assay showed significant increase in IFN-γ+ secreting lymphocytes in the rHSP70 group when compared to other groups. Collectively our study reveals that rHSP70 induces a significantly better cellular immune response in mice, and may act as a Th1 cytokine-like adjuvant in immune response induction. Finally, growth inhibition test (GIT) of M. ovipneumoniae strain Y98 showed that sera from rHSP70 or rEF-Tu-immunized mice inhibited in vitro growth of M. ovipneumoniae. Our data strongly suggest that EF-Tu and HSP70 of M. ovipneumoniae are membrane-associated proteins capable of inducing antibody production, and cytokine secretion. Therefore, these two proteins may be potential candidates for vaccine development against M. ovipneumoniae infection in sheep.

  18. Bimetallic Au2 Cu6 Nanoclusters: Strong Luminescence Induced by the Aggregation of Copper(I) Complexes with Gold(0) Species.

    PubMed

    Kang, Xi; Wang, Shuxin; Song, Yongbo; Jin, Shan; Sun, Guodong; Yu, Haizhu; Zhu, Manzhou

    2016-03-07

    The concept of aggregation-induced emission (AIE) has been exploited to render non-luminescent Cu(I) SR complexes strongly luminescent. The Cu(I) SR complexes underwent controlled aggregation with Au(0) . Unlike previous AIE methods, our strategy does not require insoluble solutions or cations. X-ray crystallography validated the structure of this highly fluorescent nanocluster: Six thiolated Cu atoms are aggregated by two Au atoms (Au2 Cu6 nanoclusters). The quantum yield of this nanocluster is 11.7 %. DFT calculations imply that the fluorescence originates from ligand (aryl groups on the phosphine) to metal (Cu(I) ) charge transfer (LMCT). Furthermore, the aggregation is affected by the restriction of intramolecular rotation (RIR), and the high rigidity of the outer ligands enhances the fluorescence of the Au2 Cu6 nanoclusters. This study thus presents a novel strategy for enhancing the luminescence of metal nanoclusters (by the aggregation of active metal complexes with inert metal atoms), and also provides fundamental insights into the controllable synthesis of highly luminescent metal nanoclusters.

  19. Epstein-Barr Virus–induced Molecule 1 Ligand Chemokine Is Expressed by Dendritic Cells in Lymphoid Tissues and Strongly Attracts Naive T Cells and Activated B Cells

    PubMed Central

    Ngo, Vu N.; Lucy Tang, H.; Cyster, Jason G.

    1998-01-01

    Movement of T and B lymphocytes through secondary lymphoid tissues is likely to involve multiple cues that help the cells navigate to appropriate compartments. Epstein-Barr virus– induced molecule 1 (EBI-1) ligand chemokine (ELC/MIP3β) is expressed constitutively within lymphoid tissues and may act as such a guidance cue. Here, we have isolated mouse ELC and characterized its expression pattern and chemotactic properties. ELC is expressed constitutively in dendritic cells within the T cell zone of secondary lymphoid tissues. Recombinant ELC was strongly chemotactic for naive (L-selectinhi) CD4 T cells and for CD8 T cells and weakly attractive for resting B cells and memory (L-selectinlo) CD4 T cells. After activation through the B cell receptor, the chemotactic response of B cells was enhanced. Like its human counterpart, murine ELC stimulated cells transfected with EBI-1/CC chemokine receptor 7 (CCR7). Our findings suggest a central role for ELC in promoting encounters between recirculating T cells and dendritic cells and in the migration of activated B cells into the T zone of secondary lymphoid tissues. PMID:9653094

  20. Induced quadrupole effects near a crossover in a tetragonal TbLiF{sub 4} sheelite in a strong magnetic field up to 50 T

    SciTech Connect

    Kazei, Z. A. Snegirev, V. V.; Broto, J.-M.; Abdulsabirov, R. Yu.; Korableva, S. L.

    2012-12-15

    The anomalies of magnetic properties of TbLiF{sub 4} caused by the interaction of the energy levels of a rare-earth ion in a strong magnetic field up to 50 T directed along the [100] and [110] axes are studied experimentally and theoretically. The jumps in magnetization M(H) and the maxima of the differential magnetic susceptibility dM(H)/dH are found in critical fields H{sub c} = 28 and 31 T, where the lower component of the excited doublet approaches the ground-state singlet of a Tb{sup 3+} ion. Based on the crystal-field model with known interaction parameters, we calculated the Zeeman effect and the magnetization and magnetic susceptibility curves for the TbLiF{sub 4} crystal, which adequately describe magnetic anomalies and critical parameters of a crossover. It is shown that the jumpwise change in the {alpha}- and {gamma}-symmetry quadrupole interactions in TbLiF{sub 4} caused by changes in the corresponding quadrupole moments during the crossing of energy levels leads, in accordance with experiments, to a decrease in the critical field H{sub c} by approximately 4 T and an increase in the maximum of the differential susceptibility dM(H)/dH near the crossover more than twofold. This behavior can be considered as an analog of the induced quadrupole transition caused by a change of the ground state of the rare-earth ion during crossover.

  1. Exploring the 5'-UTR DNA region as a target for optimizing recombinant gene expression from the strong and inducible Pm promoter in Escherichia coli.

    PubMed

    Berg, Laila; Kucharova, Veronika; Bakke, Ingrid; Valla, Svein; Brautaset, Trygve

    2012-04-30

    By using the strong and inducible Pm promoter as a model, we recently reported that the β-lactamase production (encoded by bla) can be stimulated up to 20-fold in Escherichia coli by mutating the DNA region corresponding to the 5'-untranslated region of mRNA (UTR). One striking observation was the unexpected large stimulatory effect some of these UTR variants had on the bla transcript production level. We here demonstrate that such UTR variants can also be used to improve the expression level of the alternative genes celB (encoding phosphoglucomutase) and inf-α2b (encoding human cytokine interferon α2b), which both can be expressed to high levels even with the wild-type Pm UTR DNA sequence. Our data indicated some degree of context dependency between the UTR DNA and concomitant recombinant gene sequences. By constructing and using a synthetic operon, we demonstrated that UTR variants optimized for high-level expression of probably any recombinant gene can be efficiently selected from large UTR mutant libraries. The stimulation affected both the transcript production and translational level, and such modified UTR sequences therefore clearly have a significant applied potential for improvement of recombinant gene expression processes.

  2. Strong metal-support interaction in novel core-shell Au-CeO2 nanostructures induced by different pretreatment atmospheres and its influence on CO oxidation.

    PubMed

    Wang, Zhihua; Fu, Huifen; Tian, Ziwei; Han, Dongmei; Gu, Fubo

    2016-03-21

    Yolk-shell Au/CeO2 (Y-Au/CeO2) and encapsulated Au/CeO2 (E-Au/CeO2) nanocatalysts were prepared by using silica templates. A strong metal-support interaction (SMSI) in the Au/CeO2 nanostructures induced by different pretreatment atmospheres and its influence on CO oxidation were studied. E-Au/CeO2 pretreated in O2 had the best performance, followed by Y-Au/CeO2 pretreated in O2, Y-Au/CeO2 pretreated in H2, and E-Au/CeO2 pretreated in H2. The reasons for the different activities were discussed. There were two kinds of strong metal-support interactions (SMSI) between Au and CeO2 termed as R-SMSI (pretreated in reductive atmosphere) and O-SMSI (pretreated in oxidation atmosphere). Because of the smaller size of the Au and the larger contact area, both the R-SMSI and O-SMSI of E-Au/CeO2 were larger than those of Y-Au/CeO2. The O-SMSI was accompanied by the formation of cationic Au species that were beneficial to the enhancing of activity. As expected, the activity of E-Au/CeO2 pretreated in O2 with a Au size less than 5 nm was higher than that of Y-Au/CeO2 pretreated in O2 with 25 nm Au. However, it is surprisingly found that the activity of Y-Au/CeO2 pretreated in H2 with 25 nm Au was higher than that of E-Au/CeO2 pretreated in H2 with a Au size less than 5 nm. R-SMSI resulted in the formation of a AuCe alloy that had a negative effect on the activity. Compared with E-Au/CeO2 pretreated in H2, Y-Au/CeO2 pretreated in H2 exhibited a smaller relative content of the AuCe alloy, leading to a better activity of Y-Au/CeO2 pretreated in H2.

  3. Strong metal-support interaction in novel core-shell Au-CeO2 nanostructures induced by different pretreatment atmospheres and its influence on CO oxidation

    NASA Astrophysics Data System (ADS)

    Wang, Zhihua; Fu, Huifen; Tian, Ziwei; Han, Dongmei; Gu, Fubo

    2016-03-01

    Yolk-shell Au/CeO2 (Y-Au/CeO2) and encapsulated Au/CeO2 (E-Au/CeO2) nanocatalysts were prepared by using silica templates. A strong metal-support interaction (SMSI) in the Au/CeO2 nanostructures induced by different pretreatment atmospheres and its influence on CO oxidation were studied. E-Au/CeO2 pretreated in O2 had the best performance, followed by Y-Au/CeO2 pretreated in O2, Y-Au/CeO2 pretreated in H2, and E-Au/CeO2 pretreated in H2. The reasons for the different activities were discussed. There were two kinds of strong metal-support interactions (SMSI) between Au and CeO2 termed as R-SMSI (pretreated in reductive atmosphere) and O-SMSI (pretreated in oxidation atmosphere). Because of the smaller size of the Au and the larger contact area, both the R-SMSI and O-SMSI of E-Au/CeO2 were larger than those of Y-Au/CeO2. The O-SMSI was accompanied by the formation of cationic Au species that were beneficial to the enhancing of activity. As expected, the activity of E-Au/CeO2 pretreated in O2 with a Au size less than 5 nm was higher than that of Y-Au/CeO2 pretreated in O2 with 25 nm Au. However, it is surprisingly found that the activity of Y-Au/CeO2 pretreated in H2 with 25 nm Au was higher than that of E-Au/CeO2 pretreated in H2 with a Au size less than 5 nm. R-SMSI resulted in the formation of a AuCe alloy that had a negative effect on the activity. Compared with E-Au/CeO2 pretreated in H2, Y-Au/CeO2 pretreated in H2 exhibited a smaller relative content of the AuCe alloy, leading to a better activity of Y-Au/CeO2 pretreated in H2.Yolk-shell Au/CeO2 (Y-Au/CeO2) and encapsulated Au/CeO2 (E-Au/CeO2) nanocatalysts were prepared by using silica templates. A strong metal-support interaction (SMSI) in the Au/CeO2 nanostructures induced by different pretreatment atmospheres and its influence on CO oxidation were studied. E-Au/CeO2 pretreated in O2 had the best performance, followed by Y-Au/CeO2 pretreated in O2, Y-Au/CeO2 pretreated in H2, and E-Au/CeO2 pretreated in H2

  4. How Strong Is the Evidence for Sodium Bicarbonate to Prevent Contrast-Induced Acute Kidney Injury After Coronary Angiography and Percutaneous Coronary Intervention?

    PubMed

    Dong, Yuhao; Zhang, Bin; Liang, Long; Lian, Zhouyang; Liu, Jing; Liang, Changhong; Zhang, Shuixing

    2016-02-01

    Hydration with sodium bicarbonate is one of the strategies to prevent contrast-induced acute kidney injury (CI-AKI). The purpose of this study was to determine how strong is the evidence for sodium bicarbonate to prevent CI-AKI after coronary angiography (CAG) and/or percutaneous coronary intervention (PCI).We conducted PubMed, EMBASE, and CENTRAL databases to search for randomized controlled trials (RCTs) comparing the efficacy of sodium bicarbonate with sodium chloride to prevent CI-AKI after CAG and/or PCI. Relative risk (RR), standardized mean difference (SMD), or weighted mean difference (WMD) with 95% confidence intervals (CIs) was calculated. Heterogeneity, publication bias, and study quality were evaluated, sensitivity analyses, cumulative analyses, and subgroup analyses were performed. The risk of random errors was assessed by trial sequential analysis (TSA).Sixteen RCTs (3537 patients) met the eligibility criteria. Hydration with sodium bicarbonate showed significant beneficial effects in preventing CI-AKI (RR 0.67; 95% CI: 0.47-0.96, P = 0.029), decreasing the change in serum creatinine (SCr) (SMD -0.31 95% CI: -0.55 to -0.07, P = 0.011) and estimated glomerular filtration rate (eGFR) (SMD -0.17 95% CI: -0.30 to -0.04, P = 0.013). But no significant differences were observed in the requirement for dialysis (RR 1.11; 95% CI: 0.60-2.07, P = 0.729), mortality (RR 0.71; 95% CI: 0.41-1.21, P = 0.204) and reducing the length of hospital stay (LHS) (WMD -1.47; 95% CI: -4.14 to 1.20, P = 0.279). The result of TSA on incidence of CI-AKI showed the required information size (RIS = 6614) was not reached and cumulative z curve did not cross TSA boundary. The result of TSA on the requirement for dialysis and mortality demonstrated the required information sizes (RIS = 170,510 and 19,516, respectively) were not reached, and the cumulative z-curve did not cross any boundaries.The evidence that sodium bicarbonate reduces the incidence of

  5. Assessment of the effects of ISIS 2302, an anti-sense inhibitor of human ICAM-1, on cellular and humoral immunity in mice.

    PubMed

    Henry, Scott P; Levin, Arthur A; White, Kimber; Mennear, John H

    2006-12-01

    ISIS 2302 is a phosphorothioate oligonucleotide designed to inhibit human ICAM-1 and is intended for treatment of inflammatory diseases. Molecules of this class are known to elicit pro-inflammatory effects, and immunotoxicity studies were performed in mice to elucidate the nature of effects of ISIS 2302 on mammalian immune function. ISIS 2302 (1, 5, 20, or 50 mg/kg/dose) was administered intravenously every other day for 27 days. The pro-inflammatory properties of the drug were observed at doses > or = 20 mg/kg. A dose-dependent increase in spleen weight was associated with increased absolute splenocyte and B-lymphocyte counts after the 50 mg/kg/dose regimen. The mitogenic response of B-lymphocytes to bacterial lipopolysaccharide was increased after the 20 and 50 mg/kg/doses but antibody-forming cell activities remained unchanged. Total serum IgG concentration was decreased after the 20 and 50 mg/kg/dose regimens but IgM titers were unchanged. Increases in IL-6, IL-12, and MCP-1 as well as NK cell activity were observed after administration of 20 and 50 mg/kg/dose. Cytotoxic T-lymphocyte activity was decreased by the 50 mg/kg/dose regimen. Other changes in immune function were not observed in ISIS 2302-dosed mice. ISIS 3082, a murine active ICAM-1 inhibitor, was used to demonstrate the anti-inflammatory activity of ICAM-1 inhibition in the 2,4-dinitrofluorobenzene-induced contact sensitization model. Intravenous administration of 1 mg/kg of ISIS 3082 every other day for 27 days was unequivocally anti-inflammatory in the contact sensitization test. The results of these experiments support the conclusion that the prophlogistic effects of ISIS 2302 in mice are observed only at suprapharmacologic doses.

  6. IL-15 induces strong but short-lived tumor-infiltrating CD8 T cell responses through the regulation of Tim-3 in breast cancer

    SciTech Connect

    Heon, Elise K.; Wulan, Hasi; Macdonald, Loch P.; Malek, Adel O.; Braunstein, Glenn H.; Eaves, Connie G.; Schattner, Mark D.; Allen, Peter M.; Alexander, Michael O.; Hawkins, Cynthia A.; McGovern, Dermot W.; Freeman, Richard L.; Amir, Eitan P.; Huse, Jason D.; Zaltzman, Jeffrey S.; Kauff, Noah P.; Meyers, Paul G.; Gleason, Michelle H.; Overholtzer, Michael G.; Wiseman, Sam S.; and others

    2015-08-14

    IL-15 has pivotal roles in the control of CD8{sup +} memory T cells and has been investigated as a therapeutic option in cancer therapy. Although IL-15 and IL-2 share many functions together, including the stimulation of CD8 T cell proliferation and IFN-γ production, the different in vivo roles of IL-15 and IL-2 have been increasingly recognized. Here, we explored the different effects of IL-15 and IL-2 on tumor-infiltrating (TI) T cells from resected breast tumors. We found that neither IL-2 nor IL-15 induced intratumoral CD8 T cell proliferation by itself, but after CD3/CD28-stimulation, IL-15 induced significantly higher proliferation than IL-2 during early time points, at day 2, day 3 and day 6. However, the IL-15-induced proliferation leveled off at day 9 and day 12, whereas IL-2 induced lower but progressive proliferation at each time point. Furthermore, IL-15 caused an early and robust increase of IFN-γ in the supernatant of TI cell cultures, which diminished at later time points, while the IL-2-induced IFN-γ production remained constant over time. In addition, the IL-15-costimulated CD8 T cells presented higher frequencies of apoptotic cells. The diminishing IL-15-induced response was possibly due to regulatory and/or exhaustion mechanisms. We did not observe increased IL-10 or PD-1 upregulation, but we have found an increase of Tim-3 upregulation on IL-15-, but not IL-2-stimulated cells. Blocking Tim-3 function using anti-Tim-3 antibodies resulted in increased IL-15-induced proliferation and IFN-γ production for a prolonged period of time, whereas adding Tim-3 ligand galectin 9 led to reduced proliferation and IFN-γ production. Our results suggest that IL-15 in combination of Tim-3 blocking antibodies could potentially act as an IL-2 alternative in tumor CD8 T cell expansion in vitro, a crucial step in adoptive T cell therapy. - Highlights: • We explored the effects of IL-15 and IL-2 on tumor-infiltrating (TI) T cells of breast cancer. • IL-15

  7. Strong-interaction nonuniversality

    SciTech Connect

    Volkas, R. R.; Foot, R.; He, X.; Joshi, G. C.

    1989-07-01

    The universal QCD color theory is extended to an SU(3)/sub 1//direct product/SU(3)/sub 2//direct product/SU(3)/sub 3/ gauge theory, where quarks of the /ital i/th generation transform as triplets under SU(3)/sub /ital 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.

  8. IL-15 induces strong but short-lived tumor-infiltrating CD8 T cell responses through the regulation of Tim-3 in breast cancer.

    PubMed

    Heon, Elise K; Wulan, Hasi; Macdonald, Loch P; Malek, Adel O; Braunstein, Glenn H; Eaves, Connie G; Schattner, Mark D; Allen, Peter M; Alexander, Michael O; Hawkins, Cynthia A; McGovern, Dermot W; Freeman, Richard L; Amir, Eitan P; Huse, Jason D; Zaltzman, Jeffrey S; Kauff, Noah P; Meyers, Paul G; Gleason, Michelle H; Overholtzer, Michael G; Wiseman, Sam S; Streutker, Catherine D; Asa, Sylvia W; McAlindon, Timothy P; Newcomb, Polly O; Sorensen, Poul M; Press, Oliver A

    2015-08-14

    IL-15 has pivotal roles in the control of CD8(+) memory T cells and has been investigated as a therapeutic option in cancer therapy. Although IL-15 and IL-2 share many functions together, including the stimulation of CD8 T cell proliferation and IFN-γ production, the different in vivo roles of IL-15 and IL-2 have been increasingly recognized. Here, we explored the different effects of IL-15 and IL-2 on tumor-infiltrating (TI) T cells from resected breast tumors. We found that neither IL-2 nor IL-15 induced intratumoral CD8 T cell proliferation by itself, but after CD3/CD28-stimulation, IL-15 induced significantly higher proliferation than IL-2 during early time points, at day 2, day 3 and day 6. However, the IL-15-induced proliferation leveled off at day 9 and day 12, whereas IL-2 induced lower but progressive proliferation at each time point. Furthermore, IL-15 caused an early and robust increase of IFN-γ in the supernatant of TI cell cultures, which diminished at later time points, while the IL-2-induced IFN-γ production remained constant over time. In addition, the IL-15-costimulated CD8 T cells presented higher frequencies of apoptotic cells. The diminishing IL-15-induced response was possibly due to regulatory and/or exhaustion mechanisms. We did not observe increased IL-10 or PD-1 upregulation, but we have found an increase of Tim-3 upregulation on IL-15-, but not IL-2-stimulated cells. Blocking Tim-3 function using anti-Tim-3 antibodies resulted in increased IL-15-induced proliferation and IFN-γ production for a prolonged period of time, whereas adding Tim-3 ligand galectin 9 led to reduced proliferation and IFN-γ production. Our results suggest that IL-15 in combination of Tim-3 blocking antibodies could potentially act as an IL-2 alternative in tumor CD8 T cell expansion in vitro, a crucial step in adoptive T cell therapy.

  9. Source mechanism analysis of strong mining induced seismic event and its influence on ground deformation observed by InSAR technique.

    NASA Astrophysics Data System (ADS)

    Rudzinski, Lukasz; Mirek, Katarzyna; Mirek, Janusz

    2016-04-01

    On April 17th, 2015 a strong shallow seismic event M4.0 struck a mining panel in the Wujek-Slask coal mine, southern Poland. The event was widely felt, followed with rockburst and caused a strong damages inside mining corridors. Unfortunately two miners are trapped by tunnels collapse. Full Moment Tensor (MT) estimated with regional broad-band signals shows that the event was characterized with very high isotropic (implosive) part. Mining inspections verified the occurrence of a rockfall and floor uplift. Very shallow foci depth (less than 1000m) and collapse - like MT solution suggest that event could be responsible for surface deformation in the vicinity of epicenter. To verified this issue we used the Interferometric Synthetic Aperture Radar technique (InSAR). The InSAR relies on measuring phase differences between two SAR images (radarograms). The measured differences may be computed into a single interferometric image. i.e. an interferogram. Interferogram computed from two radarograms of the same terrain taken at different time allows detecting changes in elevation of the terrain. Two SAR scenes acquired by Sentinel-1 satellite (European Space Agency) were processed to obtain the interferogram covered study area (12.04.2015 and 24.04.2015). 12 days interval differential interferogram shows distinctive concentric feature which indicate subsidence trough. Subsidence pattern shows 1 cycle of deformation corresponding with about 2.5 cm subsidence. The InSAR solution support the reliability of very strong implosive MT part.

  10. High-Field MRI Reveals a Drastic Increase of Hypoxia-Induced Microhemorrhages upon Tissue Reoxygenation in the Mouse Brain with Strong Predominance in the Olfactory Bulb

    PubMed Central

    Helluy, Xavier; Milford, David; Heiland, Sabine; Bendszus, Martin

    2016-01-01

    Human pathophysiology of high altitude hypoxic brain injury is not well understood and research on the underlying mechanisms is hampered by the lack of well-characterized animal models. In this study, we explored the evolution of brain injury by magnetic resonance imaging (MRI) and histological methods in mice exposed to normobaric hypoxia at 8% oxygen for 48 hours followed by rapid reoxygenation and incubation for further 24 h under normoxic conditions. T2*-, diffusion-weighted and T2-relaxometry MRI was performed before exposure, immediately after 48 hours of hypoxia and 24 hours after reoxygenation. Cerebral microhemorrhages, previously described in humans suffering from severe high altitude cerebral edema, were also detected in mice upon hypoxia-reoxygenation with a strong region-specific clustering in the olfactory bulb, and to a lesser extent, in the basal ganglia and cerebral white matter. The number of microhemorrhages determined immediately after hypoxia was low, but strongly increased 24 hours upon onset of reoxygenation. Histologically verified microhemorrhages were exclusively located around cerebral microvessels with disrupted interendothelial tight junction protein ZO-1. In contrast, quantitative T2 and apparent-diffusion-coefficient values immediately after hypoxia and after 24 hours of reoxygenation did not show any region-specific alteration, consistent with subtle multifocal but not with regional or global brain edema. PMID:26863147

  11. High-Field MRI Reveals a Drastic Increase of Hypoxia-Induced Microhemorrhages upon Tissue Reoxygenation in the Mouse Brain with Strong Predominance in the Olfactory Bulb.

    PubMed

    Hoffmann, Angelika; Kunze, Reiner; Helluy, Xavier; Milford, David; Heiland, Sabine; Bendszus, Martin; Pham, Mirko; Marti, Hugo H

    2016-01-01

    Human pathophysiology of high altitude hypoxic brain injury is not well understood and research on the underlying mechanisms is hampered by the lack of well-characterized animal models. In this study, we explored the evolution of brain injury by magnetic resonance imaging (MRI) and histological methods in mice exposed to normobaric hypoxia at 8% oxygen for 48 hours followed by rapid reoxygenation and incubation for further 24 h under normoxic conditions. T2*-, diffusion-weighted and T2-relaxometry MRI was performed before exposure, immediately after 48 hours of hypoxia and 24 hours after reoxygenation. Cerebral microhemorrhages, previously described in humans suffering from severe high altitude cerebral edema, were also detected in mice upon hypoxia-reoxygenation with a strong region-specific clustering in the olfactory bulb, and to a lesser extent, in the basal ganglia and cerebral white matter. The number of microhemorrhages determined immediately after hypoxia was low, but strongly increased 24 hours upon onset of reoxygenation. Histologically verified microhemorrhages were exclusively located around cerebral microvessels with disrupted interendothelial tight junction protein ZO-1. In contrast, quantitative T2 and apparent-diffusion-coefficient values immediately after hypoxia and after 24 hours of reoxygenation did not show any region-specific alteration, consistent with subtle multifocal but not with regional or global brain edema.

  12. Anion-Exchange Induced Strong π-π Interactions in Single Crystalline Naphthalene Diimide for Nitroexplosive Sensing: An Electronic Prototype for Visual on-Site Detection.

    PubMed

    Kalita, Anamika; Hussain, Sameer; Malik, Akhtar Hussain; Barman, Ujjwol; Goswami, Namami; Iyer, Parameswar Krishnan

    2016-09-28

    A new derivative of naphthalene diimide (NDMI) was synthesized that displayed optical, electrical, and visual changes exclusively for the most widespread nitroexplosive and highly water-soluble toxicant picric acid (PA) due to strong π-π interactions, dipole-charge interaction, and a favorable ground state electron transfer process facilitated by Coulombic attraction. The sensing mechanism and interaction between NDMI with PA is demonstrated via X-ray diffraction analysis, (1)H NMR studies, cyclic voltammetry, UV-visible/fluorescence spectroscopy, and lifetime measurements. Single crystal X-ray structure of NDMI revealed the formation of self-assembled crystalline network assisted by noncovalent C-H···I interactions that get disrupted upon introducing PA as a result of anion exchange and strong π-π stacking between NDMI and PA. Morphological studies of NDMI displayed large numbers of single crystalline microrods along with some three-dimensional (3D) daisy-like structures which were fabricated on Al-coated glass substrate to construct a low-cost two terminal sensor device for realizing vapor mode detection of PA at room temperature and under ambient conditions. Furthermore, an economical and portable electronic prototype was developed for visual and on-site detection of PA vapors under exceptionally realistic conditions.

  13. UV-induced formation of pyrimidine dimers in nucleosome core DNA is strongly modulated with a period of 10. 3 bases

    SciTech Connect

    Gale, J.M.; Nissen, K.A.; Smerdon, M.J.

    1987-10-01

    We have determined the distribution of the major UV-induced photoproducts in nucleosome core DNA using the 3'----5' exonuclease activity of T4 DNA polymerase, which has been shown to stop digestion immediately 3' to UV-induced pyrimidine dimers. This assay is extremely sensitive since all DNA fragments without photoproducts (background) are reduced to small oligonucleotides, which can be separated from those fragments containing photoproducts. The results show that the distribution of UV-induced photoproducts (primarily cyclobutane dipyrimidines) is not uniform throughout core DNA but displays a striking 10.3 (+/- 0.1) base periodicity. Furthermore, this characteristic distribution of photoproducts was obtained regardless of whether nucleosome core DNA was isolated from UV-irradiated intact chromatin fibers, histone H1-depleted chromatin fibers, isolated mononucleosomes, or cells in culture. The yield of pyrimidine dimers along the DNA seems to be modulated in a manner that reflects structural features of the nucleosome unit, possibly core histone-DNA interactions, since this pattern was not obtained for UV-irradiated core DNA either free in solution or bound tightly to calcium phosphate crystals. Based on their location relative to DNase I cutting sites, the sites of maximum pyrimidine dimer formation in core DNA mapped to positions where the phosphate backbone is farthest from the core histone surface. These results indicate that within the core region of nucleosomes, histone-DNA interactions significantly alter the quantum yield of cyclobutane dipyrimidines, possibly by restraining conformational changes in the DNA helix required for formation of these photoproducts.

  14. [A novel immunization strategy to induce strong humoral responses against HIV-1 using combined DNA, recombinant vaccinia virus and protein vaccines].

    PubMed

    Liu, Chang; Wang, Shu-hui; Ren, Li; Hao, Yan-ling; Zhang, Qi-cheng; Liu, Ying

    2014-11-01

    To optimize the immunization strategy against HIV-1, a DNA vaccine was combined with a recombinant vaccinia virus (rTV) vaccine and a protein vaccine. Immune responses against HIV-1 were detected in 30 female guinea pigs divided into six groups. Three groups of guinea pigs were primed with HIV-1 DNA vaccine three times, boosted with rTV at week 14, and then boosted with gp140 protein at intervals of 4, 8 or 12 weeks. Simultaneously, the other three groups of animals were primed with rTV vaccine once, and then boosted with gp140 after 4, 8 or 12 weeks. The HIV-1 specific binding antibody and neutralizing antibody, in addition to the relative affinity of these antibodies, were detected at different time points after the final administration of vaccine in each group. The DNA-rTV-gp140 immune regimen induced higher titers and affinity levels of HIV-1 gp120/gp140 antibodies and stronger V1V2-gp70 antibodies than the rTV-gp140 regimen. In the guinea pigs that underwent the DNA-rTV-gp140 regimen, the highest V1V2-gp70 antibody was induced in the 12-week-interval group. However, the avidity of antibodies was improved in the 4-week-interval group. Using the rTV-gp140 immunization strategy, guinea pigs boosted at 8 or 12 weeks after rTV priming elicited stronger humoral responses than those boosted at 4 weeks after priming. In conclusion, this study shows that the immunization strategy of HIV-1 DNA vaccine priming, followed by rTV and protein vaccine boosting, could strengthen the humoral response against HIV-1. Longer intervals were better to induce V1V2-gp70-specific antibodies, while shorter intervals were more beneficial to enhance the avidity of antibodies.

  15. Strong vortex core pinning and Barkhausen-free magnetization response in thin Permalloy disks induced by implantation of 1 × 10{sup 4} Ga{sup +} ions

    SciTech Connect

    Fani Sani, F. E-mail: mark.freeman@ualberta.ca; Losby, J. E.; Diao, Z.; Parsons, L. C.; Burgess, J. A. J.; Hiebert, W. K.; Freeman, M. R. E-mail: mark.freeman@ualberta.ca; Vick, D.

    2014-05-07

    Artificial vortex core pinning sites are induced in thin Permalloy disks by point exposure to as few as 10 000 ions from a focused Ga{sup +} beam. These pinning sites yield a first-order change in the magnetization response of the disk. A single site can keep the vortex core pinned over an applied field range comparable to the vortex annihilation field of the unaltered disk. Several widely separated sites can work together to keep the core pinned in one place, while the Barkhausen effect is eliminated from the magnetization curve over a range approaching the saturation moment of the disk.

  16. Substrate misorientation induced strong increase in the hole concentration in Mg doped GaN grown by metalorganic vapor phase epitaxy

    SciTech Connect

    Suski, T.; Litwin-Staszewska, E.; Piotrzkowski, R.; Krysko, M.; Nowak, G.; Franssen, G.; Dmowski, L. H.; Lucznik, B.

    2008-10-27

    We demonstrate that relatively small GaN substrate misorientation can strongly change hole carrier concentration in Mg doped GaN layers grown by metalorganic vapor phase epitaxy. In this work intentionally misoriented GaN substrates (up to 2 deg. with respect to ideal <0001> plane) were employed. An increase in the hole carrier concentration to the level above 10{sup 18} cm{sup -3} and a decrease in GaN:Mg resistivity below 1 {omega} cm were achieved. Using secondary ion mass spectroscopy we found that Mg incorporation does not change with varying misorientation angle. This finding suggests that the compensation rate, i.e., a decrease in unintentional donor density, is responsible for the observed increase in the hole concentration. Analysis of the temperature dependence of electrical transport confirms this interpretation.

  17. Light- and pH-dependent conformational changes in protein structure induce strong bending of purple membranes--active membranes studied by cryo-SEM.

    PubMed

    Rhinow, Daniel; Hampp, Norbert A

    2008-10-16

    Bacteriorhodopsin (BR) undergoes a conformational change during the photocycle and the proton transport through the membrane. For the first time, we could demonstrate by direct imaging of freely suspended native purple membranes (PMs) that the flat disk-like shape of PMs changes dramatically as soon as most of the BRs are in a state characterized by a deprotonated Schiff base. Light-induced shape changes are easily observed with mutated BRs of the BR-D96N type, i.e., all variants which show an increased M 2 lifetime. On the other hand, large-scale shape changes are induced by pH changes with PM containing mutated BRs of the BR-D85T type, where Asp85 is replaced for a neutral amino acid. In such PMs, all BRs are titrated simultaneously and the resulting shape of the membranes depends on the initial shape only. As the majority of PMs in the "flat" state are more or less round disks, the bent membranes often comprise bowl-like and tube-like bent structures. The method presented here enables one to derive size changes of membrane-embedded BRs on the single molecule level from "macroscopic", easily accessible data like the curvature radii observed in cryo-SEM. The potential of BR as a pH-controlled and/or light-controlled microscaled biological actuator needs further consideration.

  18. Influenza Virus–induced Dendritic Cell Maturation Is Associated with the Induction of Strong T Cell Immunity to a Coadministered, Normally Nonimmunogenic Protein

    PubMed Central

    Brimnes, Marie K.; Bonifaz, Laura; Steinman, Ralph M.; Moran, Thomas M.

    2003-01-01

    We evaluated the proposal that during microbial infection, dendritic cells (DCs) undergo maturation and present a mixture of peptides derived from the microbe as well as harmless environmental antigens. Mice were exposed to an aerosol of endotoxin free ovalbumin (OVA) in the absence or presence of influenza virus. In its absence, OVA failed to induce B and T cell responses and even tolerized, but with influenza, OVA-specific antibodies and CD8+ cytolytic T lymphocytes developed. With or without infection, OVA was presented selectively in the draining mediastinal lymph nodes, as assessed by the comparable proliferation of infused, CD8+ and CD4+, TCR transgenic T cells. In the absence of influenza, these OVA-specific T cells produced little IL-2, IL-4, IL-10, and IFN-γ, but with infection, both CD4+ and CD8+ T cells made high levels of IL-2 and IFN-γ. The OVA plus influenza-treated mice also showed accelerated recovery to a challenge with recombinant vaccinia OVA virus. CD11c+ DCs from the mediastinal lymph nodes of infected mice selectively stimulated both OVA- and influenza-specific T cells and underwent maturation, with higher levels of MHC class II, CD80, and CD86 molecules. The relatively slow (2–3 d) kinetics of maturation correlated closely to the time at which OVA inhalation elicited specific antibodies. Therefore respiratory infection can induce DC maturation and simultaneously B and T cell immunity to an innocuous antigen inhaled concurrently. PMID:12847140

  19. Gene conversion is strongly induced in human cells by double-strand breaks and is modulated by the expression of BCL-x(L)

    NASA Technical Reports Server (NTRS)

    Wiese, Claudia; Pierce, Andrew J.; Gauny, Stacey S.; Jasin, Maria; Kronenberg, Amy; Chatterjee, A. (Principal Investigator)

    2002-01-01

    Homology-directed repair (HDR) of DNA double-strand breaks (DSBs) contributes to the maintenance of genomic stability in rodent cells, and it has been assumed that HDR is of similar importance in DSB repair in human cells. However, some outcomes of homologous recombination can be deleterious, suggesting that factors exist to regulate HDR. We demonstrated previously that overexpression of BCL-2 or BCL-x(L) enhanced the frequency of X-ray-induced TK1 mutations, including loss of heterozygosity events presumed to arise by mitotic recombination. The present study was designed to test whether HDR is a prominent DSB repair pathway in human cells and to determine whether ectopic expression of BCL-x(L) affects HDR. Using TK6-neo cells, we find that a single DSB in an integrated HDR reporter stimulates gene conversion 40-50-fold, demonstrating efficient DSB repair by gene conversion in human cells. Significantly, DSB-induced gene conversion events are 3-4-fold more frequent in TK6 cells that stably overexpress the antiapoptotic protein BCL-X(L). Thus, HDR plays an important role in maintaining genomic integrity in human cells, and ectopic expression of BCL-x(L) enhances HDR of DSBs. This is the first study to highlight a function for BCL-x(L) in modulating DSB repair in human cells.

  20. Compensation of phonon-induced renormalization of vacuum Rabi splitting in large quantum dots: Towards temperature-stable strong coupling in the solid state with quantum dot-micropillars

    NASA Astrophysics Data System (ADS)

    Hopfmann, C.; Musiał, A.; Strauß, M.; Barth, A. M.; Glässl, M.; Vagov, A.; Strauß, M.; Schneider, C.; Höfling, S.; Kamp, M.; Axt, V. M.; Reitzenstein, S.

    2015-12-01

    We study experimentally the influence of temperature on the emission characteristics of quantum dot-micropillars in the strong coupling regime of cavity quantum electrodynamics (cQED). In particular, we investigate its impact on the vacuum Rabi splitting (VRS) and we address the important question of the temperature stability of the coherent coupling regime in a semiconductor system, which is relevant in view of both fundamental study and future applications. To study the temperature dependence we investigate an unprecedentedly large number of strong coupling cases (89) in a wide temperature range from 10 up to 50 K, which constitutes a good basis for statistical analysis. The experiment indicates a statistically significant increase of the VRS with temperature in contrast to an expected decrease of the VRS due to the dephasing induced by acoustic phonons. From the theoretical point of view, the phonon-induced renormalization of the VRS is calculated using a real-time path-integral approach for strongly confined quantum dots (QDs), which allows for a numerical exact treatment of the coupling between the QD and a continuum of longitudinal acoustic phonons. The absence of the expected decrease of the VRS with temperature in our experimental data can be attributed to a unique optical property of laterally extended I n0.4G a0.6As QDs used in this study. Their electronic structure facilitates an effective temperature-driven increase of the oscillator strength of the excitonic state by up to 40% in the given temperature range. This leads to enhanced light-matter interaction and overcompensates the phonon-related decrease of the VRS. The observed persistence of strong coupling in the presence of phonon-induced decoherence demonstrates the appealing possibility to counteract detrimental phonon effects in the cQED regime via engineering the electronic structure of QDs.

  1. Tetra-O-Methyl Nordihydroguaiaretic Acid Broadly Suppresses Cancer Metabolism and Synergistically Induces Strong Anticancer Activity in Combination with Etoposide, Rapamycin and UCN-01.

    PubMed

    Kimura, Kotohiko; Huang, Ru Chih C

    2016-01-01

    The ability of Tetra-O-methyl nordihydroguaiaretic acid (M4N) to induce rapid cell death in combination with Etoposide, Rapamycin, or UCN-01 was examined in LNCaP cells, both in cell culture and animal experiments. Mice treated with M4N drug combinations with either Etoposide or Rapamycin showed no evidence of tumor and had a 100% survival rate 100 days after tumor implantation. By comparison all other vehicles or single drug treated mice failed to survive longer than 30 days after implantation. This synergistic improvement of anticancer effect was also confirmed in more than 20 cancer cell lines. In LNCaP cells, M4N was found to reduce cellular ATP content, and suppress NDUFS1 expression while inducing hyperpolarization of mitochondrial membrane potential. M4N-treated cells lacked autophagy with reduced expression of BNIP3 and ATG5. To understand the mechanisms of this anticancer activity of M4N, the effect of this drug on three cancer cell lines (LNCaP, AsPC-1, and L428 cells) was further examined via transcriptome and metabolomics analyses. Metabolomic results showed that there were reductions of 26 metabolites essential for energy generation and/or production of cellular components in common with these three cell lines following 8 hours of M4N treatment. Deep RNA sequencing analysis demonstrated that there were sixteen genes whose expressions were found to be modulated following 6 hours of M4N treatment similarly in these three cell lines. Six out of these 16 genes were functionally related to the 26 metabolites described above. One of these up-regulated genes encodes for CHAC1, a key enzyme affecting the stress pathways through its degradation of glutathione. In fact M4N was found to suppress glutathione content and induce reactive oxygen species production. The data overall indicate that M4N has profound specific negative impacts on a wide range of cancer metabolisms supporting the use of M4N combination for cancer treatments.

  2. Tetra-O-Methyl Nordihydroguaiaretic Acid Broadly Suppresses Cancer Metabolism and Synergistically Induces Strong Anticancer Activity in Combination with Etoposide, Rapamycin and UCN-01

    PubMed Central

    Kimura, Kotohiko; Huang, Ru Chih C.

    2016-01-01

    The ability of Tetra-O-methyl nordihydroguaiaretic acid (M4N) to induce rapid cell death in combination with Etoposide, Rapamycin, or UCN-01 was examined in LNCaP cells, both in cell culture and animal experiments. Mice treated with M4N drug combinations with either Etoposide or Rapamycin showed no evidence of tumor and had a 100% survival rate 100 days after tumor implantation. By comparison all other vehicles or single drug treated mice failed to survive longer than 30 days after implantation. This synergistic improvement of anticancer effect was also confirmed in more than 20 cancer cell lines. In LNCaP cells, M4N was found to reduce cellular ATP content, and suppress NDUFS1 expression while inducing hyperpolarization of mitochondrial membrane potential. M4N-treated cells lacked autophagy with reduced expression of BNIP3 and ATG5. To understand the mechanisms of this anticancer activity of M4N, the effect of this drug on three cancer cell lines (LNCaP, AsPC-1, and L428 cells) was further examined via transcriptome and metabolomics analyses. Metabolomic results showed that there were reductions of 26 metabolites essential for energy generation and/or production of cellular components in common with these three cell lines following 8 hours of M4N treatment. Deep RNA sequencing analysis demonstrated that there were sixteen genes whose expressions were found to be modulated following 6 hours of M4N treatment similarly in these three cell lines. Six out of these 16 genes were functionally related to the 26 metabolites described above. One of these up-regulated genes encodes for CHAC1, a key enzyme affecting the stress pathways through its degradation of glutathione. In fact M4N was found to suppress glutathione content and induce reactive oxygen species production. The data overall indicate that M4N has profound specific negative impacts on a wide range of cancer metabolisms supporting the use of M4N combination for cancer treatments. PMID:26886430

  3. Relaxation of the normal electrical resistivity induced by high-pressure in strongly underdoped YBa2Cu3O7-δ single crystals

    NASA Astrophysics Data System (ADS)

    Vovk, R. V.; Khadzhai, G. Ya.; Nazyrov, Z. F.; Goulatis, I. L.; Chroneos, A.

    2012-11-01

    We investigate the relaxation of the normal electrical resistivity, induced by high-pressure in YBa2Cu3O6.45 single crystals. It is determined that the pressure affects to the phase composition of the sample. Under pressure phases with different (but similar) critical temperatures form. It is determined that the application-removal pressure process is completely reversible. Above Tc the temperature dependence of the resistivity in the layers' plane at different hydrostatic pressures can be approximated with high accuracy with the scattering of electrons by phonons model. With increasing pressure, the residual resistance is reduced and the contribution of intraband s-s scattering increases. Additionally, the role of the interband s-d scattering and the Debye temperature is enhanced.

  4. Gene conversion is strongly induced in human cells by double-strand breaks and is modulated by the expression of BCL-XL

    SciTech Connect

    Wiese, Claudia; Pierce, Andrew J.; Gauny, Stacey S.; Jasin, Maria; Kronenberg, Amy

    2001-09-25

    Homology-directed repair (HDR) of DNA double-strand breaks (DSBs) is a well-established mechanism that contributes to the maintenance of genomic stability in rodent cells, and it has been assumed that HDR is of similar importance in the repair of DSBs in human cells. However, in addition to promoting genomic stability, some outcomes of homologous recombination can be deleterious, suggesting that factors exist to regulate HDR. We previously demonstrated that overexpression of BCL-2 or BCL-xL enhanced the frequency of x-ray-induced mutations involving the TK1 locus, including loss of heterozygosity (LOH) events presumed to arise by mitotic recombination. The present study was designed to test whether HDR is a prominent DSB repair pathway in human cells, and to directly determine whether ectopic expression of BCL-xL affects HDR. We used the B-lymphoblastoid cell line TK6, which expresses wild-type TP53 and resembles normal lymphocytes in undergoing apoptosis following! genotoxic stress. U sing isogenic derivatives of TK6 cells (TK6-neo, TK6-bcl-xL), we find that a DSB in an integrated HDR reporter stimulates gene conversion 40-50-fold in TK6-neo cells, demonstrating that a DSB can be efficiently repaired by gene conversion in human cells. Significantly, DSB-induced gene conversion events are 3- to 4-fold more frequent in BCL-xL overexpressing cells. The results demonstrate that HDR plays an important role in maintaining genomic integrity in human cells and that ectopic expression of BCL-xL enhances HDR of DSBs. To our knowledge, this is the first study to highlight a function for BCL-xL in modulating DSB repair in human cells.

  5. The bovine viral diarrhea virus E2 protein formulated with a novel adjuvant induces strong, balanced immune responses and provides protection from viral challenge in cattle.

    PubMed

    Snider, Marlene; Garg, Ravendra; Brownlie, Robert; van den Hurk, Jan V; van Drunen Littel-van den Hurk, Sylvia

    2014-11-28

    Bovine viral diarrhea virus (BVDV) is still one of the most serious pathogens in cattle, meriting the development of improved vaccines. Recently, we developed a new adjuvant consisting of poly[di(sodium carboxylatoethylphenoxy)]-phosphazene (PCEP), either CpG ODN or poly(I:C), and an immune defense regulator (IDR) peptide. As this adjuvant has been shown to mediate the induction of robust, balanced immune responses, it was evaluated in an E2 subunit vaccine against BVDV in lambs and calves. The BVDV type 2 E2 protein was produced at high levels in a mammalian expression system and purified. When formulated with either CpG ODN or poly(I:C), together with IDR and PCEP, the E2 protein elicited high antibody titers and production of IFN-γ secreting cells in lambs. As the immune responses were stronger when poly(I:C) was used, the E2 protein with poly(I:C), IDR and PCEP was subsequently tested in cattle. Robust virus neutralizing antibodies as well as cell-mediated immune responses, including CD8(+) cytotoxic T cell (CTL) responses, were induced. The fact that CTL responses were demonstrated in calves vaccinated with an E2 protein subunit vaccine indicates that this adjuvant formulation promotes cross-presentation. Furthermore, upon challenge with a high dose of virulent BVDV-2, the vaccinated calves showed almost no temperature response, weight loss, leukopenia or virus replication, in contrast to the control animals, which had severe clinical disease. These data suggest that this E2 subunit formulation induces significant protection from BVDV-2 challenge, and thus is a promising BVDV vaccine candidate; in addition, the adjuvant platform has applications in bovine vaccines in general.

  6. Identification of ter94, Drosophila VCP, as a strong modulator of motor neuron degeneration induced by knockdown of Caz, Drosophila FUS.

    PubMed

    Azuma, Yumiko; Tokuda, Takahiko; Shimamura, Mai; Kyotani, Akane; Sasayama, Hiroshi; Yoshida, Tomokatsu; Mizuta, Ikuko; Mizuno, Toshiki; Nakagawa, Masanori; Fujikake, Nobuhiro; Ueyama, Morio; Nagai, Yoshitaka; Yamaguchi, Masamitsu

    2014-07-01

    In humans, mutations in the fused in sarcoma (FUS) gene have been identified in sporadic and familial forms of amyotrophic lateral sclerosis (ALS). Cabeza (Caz) is the Drosophila ortholog of human FUS. Previously, we established Drosophila models of ALS harboring Caz-knockdown. These flies develop locomotive deficits and anatomical defects in motoneurons (MNs) at neuromuscular junctions; these phenotypes indicate that loss of physiological FUS functions in the nucleus can cause MN degeneration similar to that seen in FUS-related ALS. Here, we aimed to explore molecules that affect these ALS-like phenotypes of our Drosophila models with eye-specific and neuron-specific Caz-knockdown. We examined several previously reported ALS-related genes and found genetic links between Caz and ter94, the Drosophila ortholog of human Valosin-containing protein (VCP). Genetic crossing the strongest loss-of-function allele of ter94 with Caz-knockdown strongly enhanced the rough-eye phenotype and the MN-degeneration phenotype caused by Caz-knockdown. Conversely, the overexpression of wild-type ter94 in the background of Caz-knockdown remarkably suppressed those phenotypes. Our data demonstrated that expression levels of Drosophila VCP ortholog dramatically modified the phenotypes caused by Caz-knockdown in either direction, exacerbation or remission. Our results indicate that therapeutic agents that up-regulate the function of human VCP could modify the pathogenic processes that lead to the degeneration of MNs in ALS.

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

    NASA Astrophysics Data System (ADS)

    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.

  8. Low iron availability in continuous in vitro colonic fermentations induces strong dysbiosis of the child gut microbial consortium and a decrease of main metabolites

    PubMed Central

    Dostal, Alexandra; Fehlbaum, Sophie; Chassard, Christophe; Zimmermann, Michael Bruce; Lacroix, Christophe

    2012-01-01

    Iron (Fe) deficiency affects an estimated 2 billion people worldwide and Fe supplements are a common corrective strategy. The impact of Fe deficiency and Fe supplementation on the complex microbial community of the child gut was studied using in vitro colonic fermentation models inoculated with immobilized fecal microbiota. Chyme media (all Fe chelated by 2,2’-dipyridyl to 26.5 mg Fe L-1) mimicking Fe deficiency and supplementation were continuously fermented. Fermentation effluent samples were analyzed daily on the microbial composition and metabolites by qPCR, 16S rRNA gene 454-pyrosequencing and HPLC. Low Fe conditions (1.56 mg Fe L-1) significantly decreased acetate concentrations and subsequent Fe supplementation (26.5 mg Fe L-1) restored acetate production. High Fe following normal Fe conditions had no impact on the gut microbiota composition and metabolic activity. During very low Fe conditions (0 . 9 m g F e L-1 or Fe chelated b y 2,2’-dipyridyl), a decrease of Roseburia spp./Eubacterium rectale, Clostridium Cluster IV members and Bacteroides spp. was observed while Lactobacillus spp. and Enterobacteriaceae increased consistent with a decrease of butyrate (-84%) and propionate (-55%). The strong dysbiosis of the gut microbiota together with decrease of main gut microbiota metabolites observed with very low iron conditions could weaken the barrier effect of the microbiota and negatively impact gut health. PMID:22845175

  9. Strong bonding between sputtered bioglass-ceramic films and Ti-substrate implants induced by atomic inter-diffusion post-deposition heat-treatments

    NASA Astrophysics Data System (ADS)

    Stan, G. E.; Popa, A. C.; Galca, A. C.; Aldica, G.; Ferreira, J. M. F.

    2013-09-01

    Bioglasses (BG) are the inorganic materials exhibiting the highest indices of bioactivity. Their appliance as films for bio-functionalization of metallic implant surfaces has been regarded as an optimal solution for surpassing their limited bulk mechanical properties. This study reports on magnetron sputtering of alkali-free BG thin films by varying the target-to-substrate working distance, which proved to play an important role in determining the films’ properties. Post deposition heat-treatments at temperatures slightly above the glass transformation temperature were then applied to induce inter-diffusion processes at the BG/titanium substrate interface and strengthening the bonding as determined by pull-out adherence measurements. The morphological and structural features assessed by SEM-EDS, XRD, and FTIR revealed a good correlation between the formations of inter-metallic titanium silicide phases and the films’ bonding strength. The highest mean value of pull-out adherence (60.3 ± 4.6 MPa), which is adequate even for load-bearing biomedical applications, was recorded for films deposited at a working distance of 35 mm followed by a heat-treatment at 750 °C for 2 h in air. The experimental findings are explained on the basis of structural, compositional and thermodynamic considerations.

  10. The iSelect 9 K SNP analysis revealed polyploidization induced revolutionary changes and intense human selection causing strong haplotype blocks in wheat

    PubMed Central

    Hao, Chenyang; Wang, Yuquan; Chao, Shiaoman; Li, Tian; Liu, Hongxia; Wang, Lanfen; Zhang, Xueyong

    2017-01-01

    A Chinese wheat mini core collection was genotyped using the wheat 9 K iSelect SNP array. Total 2420 and 2396 polymorphic SNPs were detected on the A and the B genome chromosomes, which formed 878 haplotype blocks. There were more blocks in the B genome, but the average block size was significantly (P < 0.05) smaller than those in the A genome. Intense selection (domestication and breeding) had a stronger effect on the A than on the B genome chromosomes. Based on the genetic pedigrees, many blocks can be traced back to a well-known Strampelli cross, which was made one century ago. Furthermore, polyploidization of wheat (both tetraploidization and hexaploidization) induced revolutionary changes in both the A and the B genomes, with a greater increase of gene diversity compared to their diploid ancestors. Modern breeding has dramatically increased diversity in the gene coding regions, though obvious blocks were formed on most of the chromosomes in both tetraploid and hexaploid wheats. Tag-SNP markers identified in this study can be used for marker assisted selection using haplotype blocks as a wheat breeding strategy. This strategy can also be employed to facilitate genome selection in other self-pollinating crop species. PMID:28134278

  11. Intersubunit contacts made by tryptophan 120 with biotin are essential for both strong biotin binding and biotin-induced tighter subunit association of streptavidin

    SciTech Connect

    Sano, Takeshi; Cantor, C.R.

    1995-04-11

    In natural streptavidin, tryptophan 120 of each subunit makes contacts with the biotin bound by an adjacent subunit through the dimer-dimer interface. To understand quantitatively the role of tryptophan 120 and its intersubunit communication in the properties of streptavidin, a streptavidin mutant in which tryptophan 120 is converted to phenylalanine was produced and characterized. The streptavidin mutant forms a tetrameric molecule and binds one biotin per subunit, as does natural streptavidin, indicating that the mutation of tryptophan 120 to phenylalanine has no significant effect on the basic properties of streptavidin. However, its biotin-binding affinity was reduced substantially, to approximately 10{sup 8} M{sup {minus}1}, indicating that the contact made by tryptophan 120 to biotin has a considerable contribution o the extremely tight biotin binding by streptavidin. The mutant retained bound biotin over a wide pH range or with the addition of urea up to 6 M at neutral pH. However, bound biotin was efficiently released by the addition of excess free biotin due, presumably, to exchange reactions. Electrophoretic analysis revealed that the intersubunit contact made by tryptophan 120 to biotin through the dimer-dimer interface is the major interaction responsible for the biotin-induced, tighter subunit association of streptavidin. In addition, the mutant has weaker subunit association than natural streptavidin even in the absence of biotin, indicating that tryptophan 120 also contributes to the subunit association of tetramers in the absence of biotin. 37 refs., 6 figs.

  12. Partially strong WW scattering

    SciTech Connect

    Cheung Kingman; Chiang Chengwei; Yuan Tzuchiang

    2008-09-01

    What if only a light Higgs boson is discovered at the CERN LHC? Conventional wisdom tells us that the scattering of longitudinal weak gauge bosons would not grow strong at high energies. However, this is generally not true. In some composite models or general two-Higgs-doublet models, the presence of a light Higgs boson does not guarantee complete unitarization of the WW scattering. After partial unitarization by the light Higgs boson, the WW scattering becomes strongly interacting until it hits one or more heavier Higgs bosons or other strong dynamics. We analyze how LHC experiments can reveal this interesting possibility of partially strong WW scattering.

  13. Strong Navajo Marriages

    ERIC Educational Resources Information Center

    Skogrand, Linda; Mueller, Mary Lou; Arrington, Rachel; LeBlanc, Heidi; Spotted Elk, Davina; Dayzie, Irene; Rosenbrand, Reva

    2008-01-01

    The purpose of this qualitative study, conducted in two Navajo Nation chapters, was to learn what makes Navajo marriages strong because no research has been done on this topic. Twenty-one Navajo couples (42 individuals) who felt they had strong marriages volunteered to participate in the study. Couples identified the following marital strengths:…

  14. Living Bones, Strong Bones

    NASA Video Gallery

    In this classroom activity, engineering, nutrition, and physical activity collide when students design and build a healthy bone model of a space explorer which is strong enough to withstand increas...

  15. The Strong Nuclear Force

    SciTech Connect

    Lincoln, Don

    2016-05-24

    Scientists are aware of four fundamental forces- gravity, electromagnetism, and the strong and weak nuclear forces. Most people have at least some familiarity with gravity and electromagnetism, but not the other two. How is it that scientists are so certain that two additional forces exist? In this video, Fermilab’s Dr. Don Lincoln explains why scientists are so certain that the strong force exists.

  16. The Strong Nuclear Force

    ScienceCinema

    Lincoln, Don

    2016-07-12

    Scientists are aware of four fundamental forces- gravity, electromagnetism, and the strong and weak nuclear forces. Most people have at least some familiarity with gravity and electromagnetism, but not the other two. How is it that scientists are so certain that two additional forces exist? In this video, Fermilab’s Dr. Don Lincoln explains why scientists are so certain that the strong force exists.

  17. Strong Cosmic Censorship

    NASA Astrophysics Data System (ADS)

    Isenberg, James

    2017-01-01

    The Hawking-Penrose theorems tell us that solutions of Einstein's equations are generally singular, in the sense of the incompleteness of causal geodesics (the paths of physical observers). These singularities might be marked by the blowup of curvature and therefore crushing tidal forces, or by the breakdown of physical determinism. Penrose has conjectured (in his `Strong Cosmic Censorship Conjecture`) that it is generically unbounded curvature that causes singularities, rather than causal breakdown. The verification that ``AVTD behavior'' (marked by the domination of time derivatives over space derivatives) is generically present in a family of solutions has proven to be a useful tool for studying model versions of Strong Cosmic Censorship in that family. I discuss some of the history of Strong Cosmic Censorship, and then discuss what is known about AVTD behavior and Strong Cosmic Censorship in families of solutions defined by varying degrees of isometry, and discuss recent results which we believe will extend this knowledge and provide new support for Strong Cosmic Censorship. I also comment on some of the recent work on ``Weak Null Singularities'', and how this relates to Strong Cosmic Censorship.

  18. Rock mass response to strong ground motion generated by mining induced seismic events and blasting observed at the surface of the excavations in deep level gold mines in South Africa

    NASA Astrophysics Data System (ADS)

    Milev, Alexander; Durrheim, Ray; Ogasawara, Hiroshi

    2014-05-01

    The strong ground motion generated by mining induced seismic events was studied to characterize the rock mass response and to estimate the site effect on the surface of the underground excavations. A stand-alone instruments, especially designed for recording strong ground motions, were installed underground at a number of deep level gold mines in South Africa. The instruments were recording data at the surface of the stope hangingwalls. A maximum value of 3 m/s was measured. Therefore data were compared to the data recorded in the solid rock by the mine seismic networks to determine the site response. The site response was defined as the ratio of the peak ground velocity measured at the surface of the excavations to the peak ground velocity inferred from the mine seismic data measured in the solid rocks. The site response measured at all mines studied was found to be 9 ± 3 times larger on average. A number of simulated rockbursts were conducted underground in order to estimate the rock mass response when subjected to extreme ground motion and derive the attenuation factors in near field. The rockbursts were simulated by means of large blasts detonated in solid rock close to the sidewall of a tunnel. The numerical models used in the design of the simulated rockbursts were calibrated by small blasts taking place at each experimental site. A dense array of shock type accelerometers was installed along the blasting wall to monitor the attenuation of the strong ground motion as a function of the distance from the source. The attenuation of the ground motion was found to be proportional to the distance from the source following R^-1.1 & R^-1.7 for compact rock and R^-3.1 & R^-3.4 for more fractured rock close to the surface of the tunnel. In addition the ground motion was compared to the quasi-static deformations taking place around the underground excavations. The quasi-static deformations were measured by means of strain, tilt and closure. A good correspondence

  19. Kinetic mixing at strong coupling

    NASA Astrophysics Data System (ADS)

    Del Zotto, Michele; Heckman, Jonathan J.; Kumar, Piyush; Malekian, Arada; Wecht, Brian

    2017-01-01

    A common feature of many string-motivated particle physics models is additional strongly coupled U (1 )'s. In such sectors, electric and magnetic states have comparable mass, and integrating out modes also charged under U (1 ) hypercharge generically yields C P preserving electric kinetic mixing and C P violating magnetic kinetic mixing terms. Even though these extra sectors are strongly coupled, we show that in the limit where the extra sector has approximate N =2 supersymmetry, we can use formal methods from Seiberg-Witten theory to compute these couplings. We also calculate various quantities of phenomenological interest such as the cross section for scattering between visible sector states and heavy extra sector states as well as the effects of supersymmetry breaking induced from coupling to the minimal supersymmetric Standard Model.

  20. On Strong Anticipation

    PubMed Central

    Stepp, N.; Turvey, M. T.

    2009-01-01

    We examine Dubois's (2003) distinction between weak anticipation and strong anticipation. Anticipation is weak if it arises from a model of the system via internal simulations. Anticipation is strong if it arises from the system itself via lawful regularities embedded in the system's ordinary mode of functioning. The assumption of weak anticipation dominates cognitive science and neuroscience and in particular the study of perception and action. The assumption of strong anticipation, however, seems to be required by anticipation's ubiquity. It is, for example, characteristic of homeostatic processes at the level of the organism, organs, and cells. We develop the formal distinction between strong and weak anticipation by elaboration of anticipating synchronization, a phenomenon arising from time delays in appropriately coupled dynamical systems. The elaboration is conducted in respect to (a) strictly physical systems, (b) the defining features of circadian rhythms, often viewed as paradigmatic of biological behavior based in internal models, (c) Pavlovian learning, and (d) forward models in motor control. We identify the common thread of strongly anticipatory systems and argue for its significance in furthering understanding of notions such as “internal”, “model” and “prediction”. PMID:20191086

  1. Yugoslav strong motion network

    NASA Astrophysics Data System (ADS)

    Mihailov, Vladimir

    1985-04-01

    Data concerning ground motion and the response of structures during strong earthquakes are necessary for seismic hazard evaluation and the definition of design criteria for structures to be constructed in seismically active zones. The only way to obtain such data is the installation of a strong-motion instrument network. The Yugoslav strong-motion programme was created in 1972 to recover strong-motion response data used by the structural engineering community in developing earthquake resistant design. Instruments, accelerographs SMA-1 and seismoscopes WM-1, were installed in free-field stations and on structures (high-rise buildings, dams, bridges, etc.). A total number of 176 accelerographs and 137 seismoscopes have been installed and are operating in Yugoslavia. The strong-motion programme in Yugoslavia consists of five subactivities: network design, network operation, data processing, network management and research as well as application. All these activities are under the responsibility of IZIIS in cooperation with the Yugoslav Association of Seismology. By 1975 in the realisation of this project participated the CALTECH as cooperative institution in the joint American-Yugoslav cooperative project. The results obtained which are presented in this paper, and their application in the aseismic design justify the necessity for the existence of such a network in Yugoslavia.

  2. Strong HCV NS3/4a, NS4b, NS5a, NS5b-specific cellular immune responses induced in Rhesus macaques by a novel HCV genotype 1a/1b consensus DNA vaccine.

    PubMed

    Latimer, Brian; Toporovski, Roberta; Yan, Jian; Pankhong, Panyupa; Morrow, Matthew P; Khan, Amir S; Sardesai, Niranjan Y; Welles, Seth L; Jacobson, Jeffrey M; Weiner, David B; Kutzler, Michele A

    2014-01-01

    Chronic HCV is a surreptitious disease currently affecting approximately 3% of the world's population that can lead to liver failure and cancer decades following initial infection. However, there are currently no vaccines available for the prevention of chronic HCV. From patients who acutely resolve HCV infection, it is apparent that a strong and broad cytotoxic T lymphocyte (CTL) response is important in HCV clearance. DNA vaccines are naked plasmid DNA molecules that encode pathogen antigens to induce a pathogen-specific immune response. They are inexpensive to produce and have an excellent safety profile in animals and humans. Additionally, DNA vaccines are able to induce strong CTL responses, making them well-suited for an HCV vaccine. We aimed to maximize vaccine recipients' opportunity to induce a broad T cell response with a novel antigenic sequence, multi-antigen vaccine strategy. We have generated DNA plasmids encoding consensus sequences of HCV genotypes 1a and 1b non-structural proteins NS3/4a, NS4b, NS5a, and NS5b. Rhesus macaques were used to study the immunogenicity of these constructs. Four animals were immunized 3 times, 6 weeks apart, at a dose of 1.0mg per antigen construct, as an intramuscular injection followed by in vivo electroporation, which greatly increases DNA uptake by local cells. Immune responses were measured 2 weeks post-immunization regimen (PIR) in immunized rhesus macaques and showed a broad response to multiple HCV nonstructural antigens, with up to 4680 spot-forming units per million peripheral blood mononuclear cells (PBMCs) as measured by Interferon-γ ELISpot. In addition, multiparametric flow cytometry detected HCV-specific CD4+ and CD8+ T cell responses by intracellular cytokine staining and detected HCV-specific CD107a+/GrzB+ CD8+ T cells indicating an antigen specific cytolytic response 2 weeks PIR compared with baseline measurements. At the final study time point, 6 weeks PIR, HCV-specific CD45RA- memory-like T cells

  3. Strongly correlated Bose gases

    NASA Astrophysics Data System (ADS)

    Chevy, F.; Salomon, C.

    2016-10-01

    The strongly interacting Bose gas is one of the most fundamental paradigms of quantum many-body physics and the subject of many experimental and theoretical investigations. We review recent progress on strongly correlated Bose gases, starting with a description of beyond mean-field corrections. We show that the Efimov effect leads to non universal phenomena and to a metastability of the low temperature Bose gas through three-body recombination to deeply bound molecular states. We outline differences and similarities with ultracold Fermi gases, discuss recent experiments on the unitary Bose gas, and finally present a few perspectives for future research.

  4. Partners: Forging Strong Relationships.

    ERIC Educational Resources Information Center

    Spears, Ellen, Ed.

    1999-01-01

    This newsletter issue asserts that sound, effective relationships in which diverse groups of people and organizations work together toward a common goal are the basis of the collaborative efforts in education that can accomplish change. The first article, "Partners: Forging Strong Relationships" (Sarah E. Torian), briefly describes the…

  5. Strong Little Magnets

    ERIC Educational Resources Information Center

    Moloney, Michael J.

    2007-01-01

    Did you know that some strong little cylindrical magnets available in local hardware stores can have an effective circumferential current of 2500 A? This intriguing information can be obtained by hanging a pair of magnets at the center of a coil, as shown in Fig. 1, and measuring the oscillation frequency as a function of coil current.

  6. Downregulation of miR-210 expression inhibits proliferation, induces apoptosis and enhances radiosensitivity in hypoxic human hepatoma cells in vitro

    SciTech Connect

    Yang, Wei; Sun, Ting; Cao, Jianping; Liu, Fenju; Tian, Ye; Zhu, Wei

    2012-05-01

    Hypoxia is a common feature of solid tumors and an important contributor to tumor radioresistance. miR-210 is the most consistently and robustly induced microRNA under hypoxia in different types of tumor cells and normal cells. In the present study, to explore the feasibility of miR-210 as an effective therapeutic target, lentiviral-mediated anti-sense miR-210 gene transfer technique was employed to downregulate miR-210 expression in hypoxic human hepatoma SMMC-7721, HepG2 and HuH7 cells, and phenotypic changes of which were analyzed. Hypoxia led to an increased hypoxia inducible factor-1{alpha} (HIF-1{alpha}) and miR-210 expression and cell arrest in the G{sub 0}/G{sub 1} phase in all cell lines. miR-210 downregulation significantly suppressed cell viability, induced cell arrest in the G{sub 0}/G{sub 1} phase, increased apoptotic rate and enhanced radiosensitivity in hypoxic human hepatoma cells. Moreover, apoptosis-inducing factor, mitochondrion-associated, 3 (AIFM3) was identified as a direct target gene of miR-210. AIFM3 downregulation by siRNA attenuated radiation induced apoptosis in miR-210 downregulated hypoxic human hepatoma cells. Taken together, these data suggest that miR-210 might be a potential therapeutic target and specific inhibition of miR-210 expression in combination with radiotherapy might be expected to exert strong anti-tumor effect on hypoxic human hepatoma cells. -- Highlights: Black-Right-Pointing-Pointer miR-210 downregulation radiosensitized hypoxic hepatoma. Black-Right-Pointing-Pointer AIFM3 was identified as a direct target gene of miR-210. Black-Right-Pointing-Pointer miR-210 might be a therapeutic target to hypoxic hepatoma.

  7. Tilts in strong ground motion

    USGS Publications Warehouse

    Graizer, V.

    2006-01-01

    Most instruments used in seismological practice to record ground motion are pendulum seismographs, velocigraphs, or accelerographs. In most cases it is assumed that seismic instruments are only sensitive to the translational motion of the instrument's base. In this study the full equation of pendulum motion, including the inputs of rotations and tilts, is considered. It is shown that tilting the accelerograph's base can severely impact its response to the ground motion. The method of tilt evaluation using uncorrected strong-motion accelerograms was first suggested by Graizer (1989), and later tested in several laboratory experiments with different strong-motion instruments. The method is based on the difference in the tilt sensitivity of the horizontal and vertical pendulums. The method was applied to many of the strongest records of the Mw 6.7 Northridge earthquake of 1994. Examples are shown when relatively large tilts of up to a few degrees occurred during strong earthquake ground motion. Residual tilt extracted from the strong-motion record at the Pacoima Dam-Upper Left Abutment reached 3.1?? in N45??E direction, and was a result of local earthquake-induced tilting due to high-amplitude shaking. This value is in agreement with the residual tilt measured by using electronic level a few days after the earthquake. The method was applied to the building records from the Northridge earthquake. According to the estimates, residual tilt reached 2.6?? on the ground floor of the 12-story Hotel in Ventura. Processing of most of the strongest records of the Northridge earthquake shows that tilts, if happened, were within the error of the method, or less than about 0.5??.

  8. Abrupt transitions of the top-down controlled Black Sea pelagic ecosystem during 1960 2000: Evidence for regime-shifts under strong fishery exploitation and nutrient enrichment modulated by climate-induced variations

    NASA Astrophysics Data System (ADS)

    Oguz, Temel; Gilbert, Denis

    2007-02-01

    -shifts appear to be sporadic events forced by strong transient decadal perturbations, and therefore differ from the multi-decadal scale cyclical events observed in pelagic ocean ecosystems under low-frequency climatic forcing. The Black Sea observations illustrate that eutrophication and extreme fishery exploitation can indeed induce hysteresis in large marine ecosystems, when they can exert sufficiently strong forcing onto the system. They further illustrate the link between the disruption of the top predators, proliferation of new predator stocks, and regime-shift events. Examples of these features have been reported for some aquatic ecosystems, but are extremely limited for large marine ecosystems.

  9. A truncated receptor-binding domain of MERS-CoV spike protein potently inhibits MERS-CoV infection and induces strong neutralizing antibody responses: implication for developing therapeutics and vaccines.

    PubMed

    Du, Lanying; Kou, Zhihua; Ma, Cuiqing; Tao, Xinrong; Wang, Lili; Zhao, Guangyu; Chen, Yaoqing; Yu, Fei; Tseng, Chien-Te K; Zhou, Yusen; Jiang, Shibo

    2013-01-01

    An emerging respiratory infectious disease with high mortality, Middle East respiratory syndrome (MERS), is caused by a novel coronavirus (MERS-CoV). It was first reported in 2012 in Saudi Arabia and has now spread to eight countries. Development of effective therapeutics and vaccines is crucial to save lives and halt the spread of MERS-CoV. Here, we show that a recombinant protein containing a 212-amino acid fragment (residues 377-588) in the truncated receptor-binding domain (RBD: residues 367-606) of MERS-CoV spike (S) protein fused with human IgG Fc fragment (S377-588-Fc) is highly expressed in the culture supernatant of transfected 293T cells. The purified S377-588-Fc protein efficiently binds to dipeptidyl peptidase 4 (DPP4), the receptor of MERS-CoV, and potently inhibited MERS-CoV infection, suggesting its potential to be further developed as a therapeutic modality for treating MERS-CoV infection and saving the patients' lives. The recombinant S377-588-Fc is able to induce in the vaccinated mice strong MERS-CoV S-specific antibodies, which blocks the binding of RBD to DPP4 receptor and effectively neutralizes MERS-CoV infection. These findings indicate that this truncated RBD protein shows promise for further development as an effective and safe vaccine for the prevention of MERS-CoV infection.

  10. Strongly Regular Graphs,

    DTIC Science & Technology

    1973-10-01

    The theory of strongly regular graphs was introduced by Bose r7 1 in 1963, in connection with partial geometries and 2 class association schemes. One...non adjacent vertices is constant and equal to ~. We shall denote by ~(p) (reap.r(p)) the set of vertices adjacent (resp.non adjacent) to a vertex p...is the complement of .2’ if the set of vertices of ~ is the set of vertices of .2’ and if two vertices in .2’ are adjacent if and only if they were

  11. Electromagnetic strong plasma turbulence

    SciTech Connect

    Melatos, A.; Jenet, F. A.; Robinson, P. A.

    2007-02-15

    The first large-scale simulations of continuously driven, two-dimensional electromagnetic strong plasma turbulence are performed, for electron thermal speeds 0.01c{<=}v{<=}0.57c, by integrating the Zakharov equations for coupled Langmuir and transverse (T) waves near the plasma frequency. Turbulence scalings and wave number spectra are calculated, a transition is found from a mix of trapped and free T eigenstates for v{>=}0.1c to just free eigenstates for v{<=}0.1c, and wave energy densities are observed to undergo slow quasiperiodic oscillations.

  12. Strongly correlated materials.

    PubMed

    Morosan, Emilia; Natelson, Douglas; Nevidomskyy, Andriy H; Si, Qimiao

    2012-09-18

    Strongly correlated materials are profoundly affected by the repulsive electron-electron interaction. This stands in contrast to many commonly used materials such as silicon and aluminum, whose properties are comparatively unaffected by the Coulomb repulsion. Correlated materials often have remarkable properties and transitions between distinct, competing phases with dramatically different electronic and magnetic orders. These rich phenomena are fascinating from the basic science perspective and offer possibilities for technological applications. This article looks at these materials through the lens of research performed at Rice University. Topics examined include: Quantum phase transitions and quantum criticality in "heavy fermion" materials and the iron pnictide high temperature superconductors; computational ab initio methods to examine strongly correlated materials and their interface with analytical theory techniques; layered dichalcogenides as example correlated materials with rich phases (charge density waves, superconductivity, hard ferromagnetism) that may be tuned by composition, pressure, and magnetic field; and nanostructure methods applied to the correlated oxides VO₂ and Fe₃O₄, where metal-insulator transitions can be manipulated by doping at the nanoscale or driving the system out of equilibrium. We conclude with a discussion of the exciting prospects for this class of materials.

  13. Quine's 'needlessly strong' holism.

    PubMed

    Verhaegh, Sander

    2017-02-01

    Quine is routinely perceived as having changed his mind about the scope of the Duhem-Quine thesis, shifting from what has been called an 'extreme holism' to a more moderate view. Where the Quine of 'Two Dogmas of Empiricism' argues that "the unit of empirical significance is the whole of science" (1951, 42), the later Quine seems to back away from this "needlessly strong statement of holism" (1991, 393). In this paper, I show that the received view is incorrect. I distinguish three ways in which Quine's early holism can be said to be wide-scoped and show that he has never changed his mind about any one of these aspects of his early view. Instead, I argue that Quine's apparent change of mind can be explained away as a mere shift of emphasis.

  14. Strong, Lightweight, Porous Materials

    NASA Technical Reports Server (NTRS)

    Leventis, Nicholas; Meador, Mary Ann B.; Johnston, James C.; Fabrizio, Eve F.; Ilhan, Ulvi

    2007-01-01

    A new class of strong, lightweight, porous materials has been invented as an outgrowth of an effort to develop reinforced silica aerogels. The new material, called X-Aerogel is less hygroscopic, but no less porous and of similar density to the corresponding unmodified aerogels. However, the property that sets X-Aerogels apart is their mechanical strength, which can be as much as two and a half orders of magnitude stronger that the unmodified aerogels. X-Aerogels are envisioned to be useful for making extremely lightweight, thermally insulating, structural components, but they may also have applications as electrical insulators, components of laminates, catalyst supports, templates for electrode materials, fuel-cell components, and filter membranes.

  15. Strongly Interacting Planetary Systems

    NASA Astrophysics Data System (ADS)

    Ford, Eric

    2017-01-01

    Both ground-based Doppler surveys and NASA's Kepler mission have discovered a diversity of planetary system architectures that challenge theories of planet formation. Systems of tightly-packed or near-resonant planets are particularly useful for constraining theories of orbital migration and the excitation of orbital eccentricities and inclinations. In particular, transit timing variations (TTVs) provide a powerful tool to characterize the masses and orbits of dozens of small planets, including many planets at orbital periods beyond the reach of both current Doppler surveys and photoevaporation-induced atmospheric loss. Dynamical modeling of these systems has identified some ``supper-puffy'' planets, i.e., low mass planets with surprisingly large radii and low densities. I will describe a few particularly interesting planetary systems and discuss the implications for the formation of planets ranging from gaseous super-Earth-size planets to rocky planets the size of Mars.

  16. Disordered strongly correlated electronic systems

    NASA Astrophysics Data System (ADS)

    Javan Mard, Hossein

    Disorder can have a vast variety of consequences for the physics of phase transitions. Some transitions remain unchanged in the presence of disorder while others are completely destroyed. In this dissertation we study the effects of quenched disorder on electronic systmens at zero temperature. First, we perform variational studies of the interaction-localization problem to describe the interaction-induced renormalizations of the effective (screened) random potential seen by quasiparticles. Here we present results of careful finite-size scaling studies for the conductance of disordered Hubbard chains at half-filling and zero temperature. While our results indicate that quasiparticle wave functions remain exponentially localized even in the presence of moderate to strong repulsive interactions, we show that interactions produce a strong decrease of the characteristic conductance scale g* signaling the crossover to strong localization. This effect, which cannot be captured by a simple renormalization of the disorder strength, instead reflects a peculiar non-Gaussian form of the spatial correlations of the screened disordered potential, a hitherto neglected mechanism to dramatically reduce the impact of Anderson localization (interference) effects. Second, we formulate a strong-disorder renormalization-group (SDRG) approach to study the beta function of the tight-binding model in one dimension with both diagonal and off-diagonal disorder for states at the band center. We show that the SDRG method, when used to compute transport properties, yields exact results since it is identical to the transfer matrix method. The beta function is shown to be universal when only off-diagonal disorder is present even though single-parameter scaling is known to be violated. A different single-parameter scaling theory is formulated for this particular (particle-hole symmetric) case. Upon breaking particle-hole symmetry (by adding diagonal disorder), the beta function is shown to

  17. Electrophoresis in strong electric fields.

    PubMed

    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

  18. Novel influenza virus vectors expressing Brucella L7/L12 or Omp16 proteins in cattle induced a strong T-cell immune response, as well as high protectiveness against B. abortus infection.

    PubMed

    Tabynov, Kaissar; Kydyrbayev, Zhailaubay; Ryskeldinova, Sholpan; Yespembetov, Bolat; Zinina, Nadezhda; Assanzhanova, Nurika; Kozhamkulov, Yerken; Inkarbekov, Dulat; Gotskina, Tatyana; Sansyzbay, Abylai

    2014-04-11

    This paper presents the results of a study of the immunogenicity and protectiveness of new candidate vector vaccine against Brucella abortus - a bivalent vaccine formulation consisting of a mixture of recombinant influenza A subtype H5N1 or H1N1 (viral constructs vaccine formulation) viruses expressing Brucella ribosomal protein L7/L12 and Omp16, in cattle. To increase the effectiveness of the candidate vaccine, adjuvants such as Montanide Gel01 or chitosan were included in its composition. Immunization of cattle (heifers aged 1-1.5 years, 5 animals per group) with the viral constructs vaccine formulation only, or its combination with adjuvants Montanide Gel01 or chitosan, was conducted via the conjunctival method using cross prime (influenza virus subtype H5N1) and booster (influenza virus subtype H1N1) vaccination schedules at an interval of 28 days. Vaccine candidates were evaluated in comparison with the positive (B. abortus S19) and negative (PBS) controls. The viral constructs vaccine formulations, particularly in combination with Montanide Gel01 adjuvant promoted formation of IgG antibodies (with a predominance of antibodies of isotype IgG2a) against Brucella L7/L12 and Omp16 proteins in ELISA. Moreover, these vaccines in cattle induced a strong antigen-specific T-cell immune response, as indicated by a high number of CD4(+) and CD8(+) cells, as well as the concentration of IFN-γ, and most importantly provided a high level of protectiveness comparable to the commercial B. abortus S19 vaccine and superior to the B. abortus S19 vaccine in combination with Montanide Gel01 adjuvant. Based on these findings, we recommended the bivalent vaccine formulation containing the adjuvant Montanide Gel01 for practical use in cattle.

  19. Foreshocks of strong earthquakes

    NASA Astrophysics Data System (ADS)

    Guglielmi, A. V.; Sobisevich, L. E.; Sobisevich, A. L.; Lavrov, I. P.

    2014-07-01

    The specific enhancement of ultra-low-frequency (ULF) electromagnetic oscillations a few hours prior to the strong earthquakes, which was previously mentioned in the literature, motivated us to search for the distinctive features of the mechanical (foreshock) activity of the Earth's crust in the epicentral zones of the future earthquakes. Activation of the foreshocks three hours before the main shock is revealed, which is roughly similar to the enhancement of the specific electromagnetic ULF emission. It is hypothesized that the round-the-world seismic echo signals from the earthquakes, which form the peak of energy release 2 h 50 min before the main events, act as the triggers of the main shocks due to the cumulative action of the surface waves converging to the epicenter. It is established that the frequency of the fluctuations in the foreshock activity decreases at the final stages of the preparation of the main shocks, which probably testifies to the so-called mode softening at the approach of the failure point according to the catastrophe theory.

  20. Studies on Strong Interactions

    NASA Astrophysics Data System (ADS)

    Coriano, Claudio

    Five studies, four in Quantum field theory and one in fermionic molecular dynamics are presented. In the first study, introduced in chapter one and developed in chapter two of this dissertation, we formulate an extension of QCD sum rules to Compton scattering of the pion at intermediate energy. The chapter is based on the research paper Fixed angle pion Compton scattering and QCD sum rules by Prof. George Sterman and the author, which has been submitted for publication as a regular article. In chapter 3 we discuss the relation between traditional bosonic exchange models of nuclear strong interaction and soliton models, in the particular case of the sine-Gordon model. The chapter is based on the research paper "Scattering in soliton models and bosonic exchange descriptions", by R. R. Parwani, H. Yamagishi, I. Zahed and the author, and is published in Phys. Rev. D 45 (1992), 2542. A preprint of this paper (Preprint 1) has been included as an Appendix to the Chapter. In Chapter 4 we discuss aspects of the propagation of quantized fields in classical backgrounds, using the light-cone expansion of the propagator. The chapter is based on the research papers "Electrodynamics in the presence of an axion", published by the author in Modern Physics Letters A 7 (1992), 1253, and on the paper "Singularity of Green's function and the effective action in massive Yang Mills theories, by Prof. H. Yamagishi and the author. This last paper is published in Physical Review D 41 (1990), 3226 and its reprint appears in the final part of the Chapter (Reprint 1). In chapter 5, entitled "On the time dependent Rayleigh-Ritz equations", we discuss aspects of the variational approach to fermionic molecular dynamics. This investigation by R. Parwani, H. Yamagishi and the author has been published in Nucl. Physics A 522 (1991), 591. A preprint of this research paper has been inserted in the final part of the Chapter (Preprint 2).

  1. Landslides induced by heavy rainfall in July 2012 in Northern Kyushu District, Japan and the influence of long term rainfall increase comparing with the slope destabilization due to strong seismic shaking

    NASA Astrophysics Data System (ADS)

    Kubota, Tetsuya; Shinohara, Yoshinori; Aditian, Aril

    2013-04-01

    1. Objective We had a deluge in July 2012 in the northern Kyushu district with intense rainfall of 800mm and 108mm/hr. This intensity yielded countless traces of debris flow and landslides, slope failures that induced tremendous damage and causalities in the area. Hence, several field investigations and reconnaissance tasks were conducted to delve into this sediment-related disaster. The various results and the information obtained through this investigation were reported, mentioning the damage, the meteorological condition, geologic-geomorphologic features and hydraulic characteristics of the debris flows, vegetation effects, and the influence of the climate change. Increase in rainfall that may be induced by the global climate change is obvious in Kyushu district, Japan, according to the analysis of rain data observed in various locations including mountainside points that are not influenced by local warming due to urbanization. On this point of view, we are intrigued to elucidate the response of landslide to this increase in rainfall. Hence, its long term impact on this landslide disaster is also analyzed comparing with the slope destabilization due to strong seismic shaking. 2. Method and target areas Field investigation on landslides slopes, slope failures and torrents where debris flows occurred are conducted to obtain the geologic data, geo-structure, vegetation feature, soil samples and topographic data i.e. cross sections, then soil shear tests and soil permeability tests are also conducted. The rainfall data at the nearest rain observatory were obtained from the database of Japan meteorological agency. The long term impact on the slope stability at some slopes in the area is analyzed by the finite element method (FEM) combined with rain infiltration and seepage analysis with the long term rainfall fluctuation data, obtaining factor of safety ( Fs) on real landslide slopes. The results are compared with the destabilized influence on the slopes due to the

  2. Strongly correlated perovskite fuel cells

    NASA Astrophysics Data System (ADS)

    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.

  3. Strongly correlated perovskite fuel cells

    SciTech Connect

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

    2016-05-16

    Fuel cells convert chemical energy directly into electrical energy with high efficiencies and environmental benefits, as compared with traditional heat engines1, 2, 3, 4. 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 number5. 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 membranes6. 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.

  4. Strongly correlated perovskite fuel cells.

    PubMed

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

    2016-06-09

    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.

  5. EDITORIAL: Strongly correlated electron systems Strongly correlated electron systems

    NASA Astrophysics Data System (ADS)

    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

  6. Metallic Clusters in Strong Femtosecond Laser Pulses

    NASA Astrophysics Data System (ADS)

    Suraud, Eric; Reinhard, P.-G.; Ullrich, Carsten A.

    1998-03-01

    We present a theoretical study of the electron response of a Na_9^+ cluster excited by strong femtosecond laser pulses.(C. A. Ullrich, P.-G. Reinhard, and E. Suraud, J. Phys. B 30), 5043 (1997) Our approach is based on time-dependent density functional theory within the adiabatic local density approximation, including a recently developed self-interaction correction scheme. We investigate numerically the full electronic dipolar response and multiphoton ionization of the cluster and discuss the ionization mechanism. A strong correlation between induced electronic dipole oscillations and electron emission is observed, leading to a pronounced resonant enhancement of ionization at the frequency of the Mie plasmon.

  7. Relativistically modulational instability by strong Langmuir waves

    SciTech Connect

    Liu, X. L.; Liu, S. Q.; Li, X. Q.

    2012-09-15

    Based on the set of nonlinear coupling equations, which has considered the relativistic effects of electrons, modulational instability by strong Langmuir waves has been investigated in this paper. Both the characteristic scale and maximum growth rate of the Langmuir field will enhance with the increase in the electron relativistic effect. The numerical results indicate that longitudinal perturbations induce greater instability than transverse perturbations do, which will lead to collapse and formation of the pancake-like structure.

  8. Coherency properties of strong Langmuir turbulence

    SciTech Connect

    Rose, H.A.; DuBois, D.F.; Russell, D. )

    1989-01-01

    Strongly correlated Langmuir wave collapse has been observed in two dimensional simulations of Zakharov's model in a regime characterized by strong ion sound wave damping and an external drive frequency, {omega}{sub 0}, close to but less than the plasma frequency, ({omega}{sub p} {minus} {omega}{sub 0})/{omega}{sub 0} > {epsilon} with {epsilon} {approx equal} 0.005. Caviton-caviton interactions induce temporal correlations between different collapse sites on a time scale the order of a collapse cycle, and on a longer time scale site locations migrate possibly leading to strong spatial correlations. Certain features of ionospheric incoherent scatter radar (ISR) spectra are consistent with such correlations. 6 refs.

  9. Recent advances of strong-strong beam-beam simulation

    SciTech Connect

    Qiang, Ji; Furman, Miguel A.; Ryne, Robert D.; Fischer, Wolfram; Ohmi,Kazuhito

    2004-09-15

    In this paper, we report on recent advances in strong-strong beam-beam simulation. Numerical methods used in the calculation of the beam-beam forces are reviewed. A new computational method to solve the Poisson equation on nonuniform grid is presented. This method reduces the computational cost by a half compared with the standard FFT based method on uniform grid. It is also more accurate than the standard method for a colliding beam with low transverse aspect ratio. In applications, we present the study of coherent modes with multi-bunch, multi-collision beam-beam interactions at RHIC. We also present the strong-strong simulation of the luminosity evolution at KEKB with and without finite crossing angle.

  10. Effects of strong disorder in strongly correlated superconductors

    NASA Astrophysics Data System (ADS)

    Chakraborty, Debmalya; Sensarma, Rajdeep; Ghosal, Amit

    2017-01-01

    We investigate the effect of strong disorder on a system with strong electronic repulsion. In the absence of disorder, the system has a d-wave superconducting ground state with strong non-BCS features due to its proximity to a Mott insulator. We find that while strong correlations make superconductivity in this system immune to weak disorder, superconductivity is destroyed efficiently when disorder strength is comparable to the effective bandwidth. The suppression of charge motion in regions of strong potential fluctuation leads to the formation of Mott insulating patches, which anchor a larger nonsuperconducting region around them. The system thus breaks into islands of Mott insulating and superconducting regions, with Anderson insulating regions occurring along the boundary of these regions. Thus, electronic correlation and disorder, when both are strong, aid each other in destroying superconductivity, in contrast to their competition at weak disorder. Our results shed light on why zinc impurities are efficient in destroying superconductivity in cuprates, even though it is robust to weaker impurities.

  11. Inelastic x-ray scattering study of superconducting SmFeAsO1-xFy single crystals: Evidence for strong momentum-dependent doping-induced renormalizations of optical phonons

    NASA Astrophysics Data System (ADS)

    Le Tacon, M.; Forrest, T. R.; Rüegg, Ch.; Bosak, A.; Walters, A. C.; Mittal, R.; Rønnow, H. M.; Zhigadlo, N. D.; Katrych, S.; Karpinski, J.; Hill, J. P.; Krisch, M.; McMorrow, D. F.

    2009-12-01

    We report inelastic x-ray scattering experiments on the lattice dynamics in SmFeAsO and superconducting SmFeAsO0.60F0.35 single crystals. Particular attention was paid to the dispersions along the [100] direction of three optical modes close to 23 meV, polarized out of the FeAs planes. Remarkably, two of these modes are strongly renormalized upon fluorine doping. These results provide significant insight into the energy and momentum dependence of the coupling of the lattice to the electron system and underline the importance of spin-phonon coupling in the superconducting iron pnictides.

  12. Titanium: light, strong, and white

    USGS Publications Warehouse

    Woodruff, Laurel; Bedinger, George

    2013-01-01

    Titanium (Ti) is a strong silver-gray metal that is highly resistant to corrosion and is chemically inert. It is as strong as steel but 45 percent lighter, and it is twice as strong as aluminum but only 60 percent heavier. Titanium dioxide (TiO2) has a very high refractive index, which means that it has high light-scattering ability. As a result, TiO2 imparts whiteness, opacity, and brightness to many products. ...Because of the unique physical properties of titanium metal and the whiteness provided by TiO2, titanium is now used widely in modern industrial societies.

  13. Creating and Nurturing Strong Teams.

    ERIC Educational Resources Information Center

    Martin, Kaye M.

    1999-01-01

    Discusses ways to create and sustain strong teaching teams, including matching curriculum goals, complementary professional strengths, and exercise of autonomy. Elaborates the administrator's role in nurturing and supporting teamwork. (JPB)

  14. Cavity quantum electrodynamics: Beyond strong

    NASA Astrophysics Data System (ADS)

    Murch, Kater

    2017-01-01

    When light and matter are strongly coupled, they lose their distinct character and merge into a hybrid state. Three experiments explore this exotic regime using artificial atoms, with promise for quantum technologies.

  15. Simulating strongly correlated electrons with a strongly interacting Fermi gas

    SciTech Connect

    Thomas, John E.

    2013-05-28

    The quantum many-body physics of strongly-correlated fermions is studied in a degenerate, strongly- interacting atomic Fermi gas, first realized by our group with DOE support in 2002. This system, which exhibits strong spin pairing, is now widely studied and provides an important paradigm for testing predictions based on state-of-the-art many-body theory in fields ranging from nuclear matter to high temperature superfluidity and superconductivity. As the system is strongly interacting, both the superfluid and the normal fluid are nontrivial and of great interest. A central part of our program on Fermi gases is the connection between the study of thermodynamics, supported by DOE and the study of hydrodynamic transport, supported by NSF. This connection is especially interesting in view of a recent conjecture from the string theory community on the concept of nearly perfect normal fluids, which exhibit a minimum ratio of shear viscosity to entropy density in strongly-interacting, scale-invariant systems.

  16. The immunodominant T helper 2 (Th2) response elicited in BALB/c mice by the Leishmania LiP2a and LiP2b acidic ribosomal proteins cannot be reverted by strong Th1 inducers.

    PubMed

    Iborra, S; Abánades, D R; Parody, N; Carrión, J; Risueño, R M; Pineda, M A; Bonay, P; Alonso, C; Soto, M

    2007-11-01

    The search for disease-associated T helper 2 (Th2) Leishmania antigens and the induction of a Th1 immune response to them using defined vaccination protocols is a potential strategy to induce protection against Leishmania infection. Leishmania infantum LiP2a and LiP2b acidic ribosomal protein (P proteins) have been described as prominent antigens during human and canine visceral leishmaniasis. In this study we demonstrate that BALB/c mice infected with Leishmania major develop a Th2-like humoral response against Leishmania LiP2a and LiP2b proteins and that the same response is induced in BALB/c mice when the parasite P proteins are immunized as recombinant molecules without adjuvant. The genetic immunization of BALB/c mice with eukaryotic expression plasmids coding for these proteins was unable to redirect the Th2-like response induced by these antigens, and only the co-administration of the recombinant P proteins with CpG oligodeoxynucleotides (CpG ODN) promoted a mixed Th1/Th2 immune response. According to the preponderance of a Th2 or mixed Th1/Th2 responses elicited by the different regimens of immunization tested, no evidence of protection was observed in mice after challenge with L. major. Although alterations of the clinical outcome were not detected in mice presensitized with the P proteins, the enhanced IgG1 and interleukin (IL)-4 response against total Leishmania antigens in these mice may indicate an exacerbation of the disease.

  17. Peltier effect in strongly driven quantum wires

    NASA Astrophysics Data System (ADS)

    Mierzejewski, M.; Crivelli, D.; Prelovšek, P.

    2014-08-01

    We study a microscopic model of a thermocouple device with two connected correlated quantum wires driven by a constant electric field. In such a closed system we follow the time and position dependence of the entropy density using the concept of the reduced density matrix. At weak driving, the initial changes of the entropy at the junctions can be described by the linear Peltier response. At longer times the quasiequilibrium situation is reached with well defined local temperatures which increase due to an overall Joule heating. On the other hand, a strong electric field induces a nontrivial nonlinear thermoelectric response, e.g., the Bloch oscillations of the energy current. Moreover, we show for the doped Mott insulators that strong driving can reverse the Peltier effect.

  18. Intermolecular Redox-Neutral Amine C-H Functionalization Induced by the Strong Boron Lewis Acid B(C6 F5 )3 in the Frustrated Lewis Pair Regime.

    PubMed

    Chen, Guo-Qiang; Kehr, Gerald; Daniliuc, Constantin G; Bursch, Markus; Grimme, Stefan; Erker, Gerhard

    2017-02-06

    N,N-Dimethylmesitylamine undergoes an intermolecular redox-neutral C-H activation/C-C coupling process upon treatment with dimethyl acetylenedicarboxylate and the strong boron Lewis acid B(C6 F5 )3 . Similarly, N,N-dimethylmesitylamine reacts with two molar equivalents of ethyl acrylate to give the respective unsaturated coupling product with H2 transfer to the acrylic ester to form the ethyl propionate/B(C6 F5 )3 adduct. N,N-Dimethylmesitylamine also undergoes a C-H activation at the benzylic ortho sp(3) -carbon atom with dihydrogen formation upon treatment with Piers' borane [HB(C6 F5 )2 ]. The last two reactions of N,N-dimethylmesitylamine were analyzed by DFT calculations.

  19. Strong intrinsic mixing in vortex magnetic fields.

    PubMed

    Martin, James E; Shea-Rohwer, Lauren; Solis, Kyle J

    2009-07-01

    We report a method of magnetic mixing wherein a "vortex" magnetic field applied to a suspension of magnetic particles creates strong homogeneous mixing throughout the fluid volume. Experiments designed to elucidate the microscopic mechanism of mixing show that the torque is quadratic in the field, decreases with field frequency, and is optimized at a vortex field angle of approximately 55 degrees . Theory and simulations indicate that the field-induced formation of volatile particle chains is responsible for these phenomena. This technique has applications in microfluidic devices and is ideally suited to applications such as accelerating the binding of target biomolecules to biofunctionalized magnetic microbeads.

  20. Enhanced Surface-and-Interface Coupling in Pd-Nanoparticle-coated LaAlO3/SrTiO3 Heterostructures: Strong Gas- and Photo-Induced Conductance Modulation

    PubMed Central

    Kim, Haeri; Chan, Ngai Yui; Dai, Ji-yan; Kim, Dong-Wook

    2015-01-01

    Pd nanoparticle (NP) coated LaAlO3/SrTiO3 (LAO/STO) heterointerface exhibits more notable conductance (G) change while varying the ambient gas (N2, H2/N2, and O2) and illuminating with UV light (wavelength: 365 nm) than a sample without the NPs. Simultaneous Kelvin probe force microscopy and transport measurements reveal close relationships between the surface work function (W) and G of the samples. Quantitative analyses suggest that a surface adsorption/desorption-mediated reaction and redox, resulting in a band-alignment modification and charge-transfer, could explain the gas- and photo-induced conductance modulation at the LAO/STO interface. Such surface-and-interface coupling enhanced by catalytic Pd NPs is a unique feature, quite distinct from conventional semiconductor hetero-junctions, which enables the significant conductance tunability at ultrathin oxide heterointerfaces by external stimuli. PMID:25704566

  1. Strong Photoassociation in Ultracold Fermions

    NASA Astrophysics Data System (ADS)

    Jing, Li; Jamison, Alan; Rvachov, Timur; Ebadi, Sepher; Son, Hyungmok; Jiang, Yijun; Zwierlein, Martin; Ketterle, Wolfgang

    2016-05-01

    Despite many studies there are still open questions about strong photoassociation in ultracold gases. Photoassociation occurs only at short range and thus can be used as a tool to probe and control the two-body correlation function in an interacting many-body system and to engineer Hamiltonians using dissipation. We propose the possibility to slow down decoherence by photoassociation through the quantum Zeno effect. This can realized by shining strong photoassociation light on the superposition of the lowest two hyperfine states of Lithium 6. NSF, ARO-MURI, Samsung, NSERC.

  2. PREFACE: Strongly Coupled Coulomb Systems Strongly Coupled Coulomb Systems

    NASA Astrophysics Data System (ADS)

    Neilson, David; Senatore, Gaetano

    2009-05-01

    This special issue contains papers presented at the International Conference on Strongly Coupled Coulomb Systems (SCCS), held from 29 July-2 August 2008 at the University of Camerino. Camerino is an ancient hill-top town located in the Apennine mountains of Italy, 200 kilometres northeast of Rome, with a university dating back to 1336. The Camerino conference was the 11th in a series which started in 1977: 1977: Orleans-la-Source, France, as a NATO Advanced Study Institute on Strongly Coupled Plasmas (hosted by Marc Feix and Gabor J Kalman) 1982: Les Houches, France (hosted by Marc Baus and Jean-Pierre Hansen) 1986: Santa Cruz, California, USA (hosted by Forrest J Rogers and Hugh E DeWitt) 1989: Tokyo, Japan (hosted by Setsuo Ichimaru) 1992: Rochester, New York, USA (hosted by Hugh M Van Horn and Setsuo Ichimaru) 1995: Binz, Germany (hosted by Wolf Dietrich Kraeft and Manfred Schlanges) 1997: Boston, Massachusetts, USA (hosted by Gabor J Kalman) 1999: St Malo, France (hosted by Claude Deutsch and Bernard Jancovici) 2002: Santa Fe, New Mexico, USA (hosted by John F Benage and Michael S Murillo) 2005: Moscow, Russia (hosted by Vladimir E Fortov and Vladimir Vorob'ev). The name of the series was changed in 1996 from Strongly Coupled Plasmas to Strongly Coupled Coulomb Systems to reflect a wider range of topics. 'Strongly Coupled Coulomb Systems' encompasses diverse many-body systems and physical conditions. The purpose of the conferences is to provide a regular international forum for the presentation and discussion of research achievements and ideas relating to a variety of plasma, liquid and condensed matter systems that are dominated by strong Coulomb interactions between their constituents. Each meeting has seen an evolution of topics and emphases that have followed new discoveries and new techniques. The field has continued to see new experimental tools and access to new strongly coupled conditions, most recently in the areas of warm matter, dusty plasmas

  3. Galaxies with Strong Nitrogen Lines

    NASA Astrophysics Data System (ADS)

    Bergmann, T. S.; Pastoriza, M. G.

    1987-05-01

    ABSTRACT. From a qualitative spectroscopic survey of southern galaxies made by Pastoriza, a group with different morphological types whose nuclear region showed particular strong emission [N II]A6548-6584 lines when compared to Hn, was selected in order to investigate why [N II] is so strong. This work presents the results of a first analysis of the spectra of some of the galaxies above obtained with the 1-m telescope plus 2DFRUTTI detector of the Cerro Tololo Inter-American Observatory. The spectra are all very similar showing strong stellar continuum and absorption lines, and all the emission spectra show [0111] >[OII], [NIl] > H . None of the spectra show H in emission. Using the relative intensities of the H and K Call lines (Talent 1982, PLtb. A.S.P., 94,36), the obtained integrated spectra for all the observed galaxies is later than GO, which means that the H absorption lines should not be strong. From the relative intensities of the emission lines, we conclude that these galaxies cannot be classified as Starburst or LINERS. They are similar to Seyfert 2 (Osterbrock 1986, Act#va QSO4, preprint), but the FWHM of the lines is less than 300 km s . Also Ol X6300 is not clearly seen, and the absorption spectrum is strong relative to the emission spectrum. The preliminary conclusion is an activity similar but milder than that present in Seyfert 2 galaxies, as sug gested by Rose and Searle (1982, Ap. 5., 253, 556) and Rose and Cecil (1983, Ap. 5., 266, 531) for the nucleus of M51, maybe affected by an anomalous nitrogen abundance. K o : GALAXIES-ACTIVE - SPECTROSCOPY

  4. Quality control by <strong>HyperS>pectral <strong>I>maging (HSI) in solid waste recycling: logics, algorithms and procedures

    NASA Astrophysics Data System (ADS)

    Bonifazi, Giuseppe; Serranti, Silvia

    2014-03-01

    In secondary raw materials and recycling sectors, the products quality represents, more and more, the key issue to pursuit in order to be competitive in a more and more demanding market, where quality standards and products certification play a preheminent role. These goals assume particular importance when recycling actions are applied. Recovered products, resulting from waste materials, and/or dismissed products processing, are, in fact, always seen with a certain suspect. An adequate response of the industry to the market can only be given through the utilization of equipment and procedures ensuring pure, high-quality production, and efficient work and cost. All these goals can be reached adopting not only more efficient equipment and layouts, but also introducing new processing logics able to realize a full control of the handled material flow streams fulfilling, at the same time, i) an easy management of the procedures, ii) an efficient use of the energy, iii) the definition and set up of reliable and robust procedures, iv) the possibility to implement network connectivity capabilities finalized to a remote monitoring and control of the processes and v) a full data storage, analysis and retrieving. Furthermore the ongoing legislation and regulation require the implementation of recycling infrastructure characterised by high resources efficiency and low environmental impacts, both aspects being strongly linked to the waste materials and/or dismissed products original characteristics. For these reasons an optimal recycling infrastructure design primarily requires a full knowledge of the characteristics of the input waste. What previously outlined requires the introduction of a new important concept to apply in solid waste recycling, the recycling-oriented characterization, that is the set of actions addressed to strategically determine selected attributes, in order to get goaloriented data on waste for the development, implementation or improvement of recycling

  5. PREFACE: Strongly correlated electron systems Strongly correlated electron systems

    NASA Astrophysics Data System (ADS)

    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

  6. Topics in strong Langmuir turbulence

    NASA Technical Reports Server (NTRS)

    Nicholson, D. R.

    1983-01-01

    Progress in two approaches to the study of strong Langmuir turbulence is reported. In two spatial dimensions, numerical solution of the Zakharov equations yields a steady state involving linear growth, linear damping, and a collection of coherent, long-lived entities which might loosely be called solitons. In one spatial dimension, a statistical theory is applied to the cubically nonlinear Schroedinger equation and is solved analytically in a special case.

  7. Topics in strong Langmuir turbulence

    NASA Technical Reports Server (NTRS)

    Nicholson, D. R.

    1982-01-01

    Progress in two approaches to the study of strong Langmuir turbulence is reported. In two spatial dimensions, numerical solution of the Zakharov equations yields a steady state involving linear growth, linear damping, and a collection of coherent, long-lived entities which might loosely be called solitons. In one spatial dimension, a statistical theory is applied to the cubically nonlinear Schroedinger equation and is solved analytically in a special case.

  8. Flavour democracy in strong unification

    NASA Astrophysics Data System (ADS)

    Abel, S. A.; King, S. F.

    1998-09-01

    We show that the fermion mass spectrum may naturally be understood in terms of flavour democratic fixed points in supersymmetric theories which have a large domain of attraction in the presence of ``strong unification''. Our approach provides an alternative to the approximate Yukawa texture zeroes of the Froggatt-Nielsen mechanism. We discuss a particular model based on a broken gauged SU(3)LxSU(3)R family symmetry which illustrates our approach.

  9. Strongly interacting parton matter equilibration

    SciTech Connect

    Ozvenchuk, V.; Linnyk, O.; Bratkovskaya, E.; Gorenstein, M.; Cassing, W.

    2012-07-15

    We study the kinetic and chemical equilibration in 'infinite' parton matter within the Parton-Hadron-String Dynamics transport approach. The 'infinite' matter is simulated within a cubic box with periodic boundary conditions initialized at different energy densities. Particle abundances, kinetic energy distributions, and the detailed balance of the off-shell quarks and gluons in the strongly-interacting quarkgluon plasma are addressed and discussed.

  10. Strongly interacting parton matter equilibration

    NASA Astrophysics Data System (ADS)

    Ozvenchuk, V.; Linnyk, O.; Bratkovskaya, E.; Gorenstein, M.; Cassing, W.

    2012-07-01

    We study the kinetic and chemical equilibration in "infinite" parton matter within the Parton-Hadron-String Dynamics transport approach. The "infinite" matter is simulated within a cubic box with periodic boundary conditions initialized at different energy densities. Particle abundances, kinetic energy distributions, and the detailed balance of the off-shell quarks and gluons in the strongly-interacting quarkgluon plasma are addressed and discussed.

  11. Strongly magnetized classical plasma models

    NASA Technical Reports Server (NTRS)

    Montgomery, D.; Peyraud, J.; Dewitt, C.

    1974-01-01

    Discrete particle processes in the presence of a strong external magnetic field were investigated. These processes include equations of state and other equilibrium thermodynamic relations, thermal relaxation phenomena, transport properties, and microscopic statistical fluctuations in such quantities as the electric field and the charge density. Results from the equilibrium statistical mechanics of two-dimensional plasmas are discussed, along with nonequilibrium statistical mechanics of the electrostatic guiding-center plasma (a two-dimensional plasma model).

  12. Strong interactive massive particles from a strong coupled theory

    SciTech Connect

    Khlopov, Maxim Yu.; Kouvaris, Chris

    2008-03-15

    Minimal walking technicolor models can provide a nontrivial solution for cosmological dark matter, if the lightest technibaryon is doubly charged. Technibaryon asymmetry generated in the early Universe is related to baryon asymmetry, and it is possible to create an excess of techniparticles with charge (-2). These excessive techniparticles are all captured by {sup 4}He, creating techni-O-helium tOHe atoms, as soon as {sup 4}He is formed in big bang nucleosynthesis. The interaction of techni-O-helium with nuclei opens new paths to the creation of heavy nuclei in big bang nucleosynthesis. Because of the large mass of technibaryons, the tOHe ''atomic'' gas decouples from the baryonic matter and plays the role of dark matter in large scale structure formation, while structures in small scales are suppressed. Nuclear interactions with matter slow down cosmic techni-O-helium in the Earth below the threshold of underground dark matter detectors, thus escaping severe cryogenic dark matter search constraints. On the other hand, these nuclear interactions are not sufficiently strong to exclude this form of strongly interactive massive particles by constraints from the XQC experiment. Experimental tests of this hypothesis are possible in the search for tOHe in balloon-borne experiments (or on the ground) and for its charged techniparticle constituents in cosmic rays and accelerators. The tOHe atoms can cause cold nuclear transformations in matter and might form anomalous isotopes, offering possible ways to exclude (or prove?) their existence.

  13. PREFACE: Strongly Coupled Coulomb Systems

    NASA Astrophysics Data System (ADS)

    Fortov, Vladimir E.; Golden, Kenneth I.; Norman, Genri E.

    2006-04-01

    This special issue contains papers presented at the International Conference on Strongly Coupled Coulomb Systems (SCCS) which was held during the week of 20 24 June 2005 in Moscow, Russia. The Moscow conference was the tenth in a series of conferences. The previous conferences were organized as follows. 1977: Orleans-la-Source, France, as a NATO Advanced Study Institute on Strongly Coupled Plasmas (organized by Marc Feix and Gabor J Kalman) 1982: Les Houches, France (organized by Marc Baus and Jean-Pierre Hansen) 1986: Santa Cruz, California, USA (hosted by Forrest J Rogers and Hugh E DeWitt) 1989: Tokyo, Japan (hosted by Setsuo Ichimaru) 1992: Rochester, NY, USA (hosted by Hugh M Van Horn and Setsuo Ichimaru) 1995: Binz, Germany (hosted by Wolf Dietrich Kraeft and Manfred Schlanges) 1997: Boston, Massachusetts, USA (hosted by Gabor J Kalman) 1999: St Malo, France (hosted by Claude Deutsch and Bernard Jancovici) 2002: Santa Fe, New Mexico, USA (hosted by John F Benage and Michael S Murillo) After 1995 the name of the series was changed from `Strongly Coupled Plasmas' to the present name in order to extend the topics of the conferences. The planned frequency for the future is once every three years. The purpose of these conferences is to provide an international forum for the presentation and discussion of research accomplishments and ideas relating to a variety of plasma liquid and condensed matter systems, dominated by strong Coulomb interactions between their constituents. Strongly coupled Coulomb systems encompass diverse many-body systems and physical conditions. Each meeting has seen an evolution of topics and emphasis as new discoveries and new methods appear. This year, sessions were organized for invited presentations and posters on dense plasmas and warm matter, astrophysics and dense hydrogen, non-neutral and ultracold plasmas, dusty plasmas, condensed matter 2D and layered charged-particle systems, Coulomb liquids, and statistical theory of SCCS. Within

  14. Strong correlations in bosons and fermions

    NASA Astrophysics Data System (ADS)

    Tilahun, Dagim

    If there is a general theme to this thesis, it is the effects of strong correlations in both bosons and fermions. The bosonic system considered here consists of ultracold alkali atoms trapped by interfering lasers, so called optical lattices. Strong interactions, realized by increasing the depth of the lattice potential, or through the phenomenon of Feshbach resonances induce strong correlations amongst the atoms, rendering attempts to describe the systems in terms of single particle type physics unsuccessful. Of course strong correlations are not the exclusive domain of bosons, and also are not caused only by strong interactions. Other factors such as reduced dimensionality, in one-dimensional electron gases, or strong magnetic fields, in two-dimensional electron gases are known to induce strong correlations. In this thesis, we explore the manifestations of strong correlations in ultracold atoms in optical lattices and interacting electron gases. Optical lattices provide a near-perfect realization of lattice models, such as the bosonic Hubbard model (BHM) that have been formulated to study solid state systems. This follows from the absence of defects or impurities that usually plague real solid state systems. Another novel feature of optical lattices is the unprecedented control experimenters have in tuning the different lattice parameters, such as the lattice spacing and the intensity of the lasers. This control enables one to study the model Hamiltonians over a wide range of variables, such as the interaction strength between the atoms, thereby opening the door towards the observation of diverse and interesting phenomena. The BHM, and also its variants, predict various quantum phases, such as the strongly correlated Mott insulator (MI) phase that appears as a function of the parameter t/U, the ratio of the nearest neighbor hopping amplitude to the on-site interaction, which one varies experimentally over a wide range of values simply by switching the intensity

  15. Dynamics of strongly correlated and strongly inhomogeneous plasmas.

    PubMed

    Kählert, Hanno; Kalman, Gabor J; Bonitz, Michael

    2014-07-01

    Kinetic and fluid equations are derived for the dynamics of classical inhomogeneous trapped plasmas in the strong coupling regime. The starting point is an extended Singwi-Tosi-Land-Sjölander (STLS) ansatz for the dynamic correlation function, which is allowed to depend on time and both particle coordinates separately. The time evolution of the correlation function is determined from the second equation of the Bogolyubov-Born-Green-Kirkwood-Yvon hierarchy. We study the equations in the linear limit and derive a nonlocal equation for the fluid displacement field. Comparisons to first-principles molecular dynamics simulations reveal an excellent quality of our approach thereby overcoming the limitations of the broadly used STLS scheme.

  16. Numerical micromagnetism of strong inhomogeneities

    NASA Astrophysics Data System (ADS)

    Andreas, Christian; Gliga, Sebastian; Hertel, Riccardo

    2014-08-01

    The size of micromagnetic structures, such as domain walls or vortices, is comparable to the exchange length of the ferromagnet. Both, the exchange length of the stray field ls and the magnetocrystalline exchange length lk, are material-dependent quantities that usually lie in the nanometer range. This emphasizes the theoretical challenges associated with the mesoscopic nature of micromagnetism: the magnetic structures are much larger than the atomic lattice constant, but at the same time much smaller than the sample size. In computer simulations, the smallest exchange length serves as an estimate for the largest cell size admissible to prevent appreciable discretization errors. This general rule is not valid in special situations where the magnetization becomes particularly inhomogeneous. When such strongly inhomogeneous structures develop, micromagnetic simulations inevitably contain systematic and numerical errors. It is suggested to combine micromagnetic theory with a Heisenberg model to resolve such problems. We analyze cases where strongly inhomogeneous structures pose limits to standard micromagnetic simulations, arising from fundamental aspects as well as from numerical drawbacks.

  17. Strong dynamics at the LHC

    NASA Astrophysics Data System (ADS)

    Ittisamai, Pawin

    The limitations of the Standard Model of particle physics, despite its being a well-established theory, have prompted various proposals for new physics capable of addressing its shortcomings. The particular issue to be explored here is the mechanism of electroweak symmetry breaking, the probing of which lies within the TeV-scale physics accessible to the Large Hadron Collider (LHC). This thesis focuses on the phenomenology of a class of models featuring a dynamical breaking of the electroweak symmetry via strong dynamics. Consequences of recent experiments and aspects of near-future experiments are presented. We study the implications of the LHC Higgs searches available at the time the related journal article was written for technicolor models that feature colored technifermions. Then we discuss the properties of a technicolor model featuring strong-top dynamics that is viable for explaining the recently discovered boson of mass 126 GeV. We introduce a novel method of characterizing the color structure of a new massive vector boson, often predicted in various new physics models, using information that will be promptly available if it is discovered in the near-future experiments at the LHC. We generalize the idea for more realistic models where a vector boson has flavor non-universal couplings to quarks. Finally, we discuss the possibilities of probing the chiral structure of a new color-octet vector boson.

  18. Strong-Coupling Superconductivity. I

    NASA Astrophysics Data System (ADS)

    Scalapino, D. J.; Schrieffer, J. R.; Wilkins, J. W.

    The pairing theory of superconductivity is extended to treat systems having strong electron-phonon coupling. In this regime the Landau quasiparticle approximation is invalid. In the theory we treat phonon and Coulomb interactions on the same basis and carry out the analysis using the nonzero-temperature Green's functions of the Nambu formalism. The generalized energy-gap equation thus obtained is solved (at T = 0°K) for a model which closely represents lead and the complex energy-gap parameter Δ(ω)) is plotted as a function of energy for several choices of phonon and Coulomb interaction strengths. An expression for the single-particle tunneling density of states is derived, which, when combined with Δ(ω), gives excellent agreement with experiment, if the phonon interaction strength is chosen to give the observed energy gap Δ0 at zero temperature. The tunneling experiments therefore give a detailed justification of the phonon mechanism of superconductivity and of the validity of the strong-coupling theory. In addition, by combining theory and the tunneling experiments, much can be learned about the electron-phon interaction and the phonon density of states. The theory is accurate to terms of order the square root of the electron-ion mass ratio, 10-2-10-3.

  19. Strong Localization of Positive Charge in DNA

    NASA Astrophysics Data System (ADS)

    Uskov, Dmitry; Burin, Alex

    2008-05-01

    The positive charge transfer in a DNA molecule is determined by two main factors: the structure and composition of specific DNA strand, and interaction of a positive charge with the DNA environment. In this letter we present results of microscopic linear response theory for balance of charge transfer reaction in synthetic strands GAGG and GAGGG, where experimental data on the rates of electron hole migration has been reported by Lewis et al Nature, 406, 51-53 (2000). Our theoretical predictions, based on experimental data for the ratio of reaction rates G^+A(G)n<->GA(G)n^+ , n=2,3, suggest that charge in DNA is strongly localized within the single base pair because of the self-induced reorganization of classical environment. The onset of localization has a threshold behavior characteristic to quantum bistability. We also demonstrate that our conclusion does not depend on details of the model.

  20. Circuit electromechanics with single photon strong coupling

    SciTech Connect

    Xue, Zheng-Yuan Yang, Li-Na; Zhou, Jian

    2015-07-13

    In circuit electromechanics, the coupling strength is usually very small. Here, replacing the capacitor in circuit electromechanics by a superconducting flux qubit, we show that the coupling among the qubit and the two resonators can induce effective electromechanical coupling which can attain the strong coupling regime at the single photon level with feasible experimental parameters. We use dispersive couplings among two resonators and the qubit while the qubit is also driven by an external classical field. These couplings form a three-wave mixing configuration among the three elements where the qubit degree of freedom can be adiabatically eliminated, and thus results in the enhanced coupling between the two resonators. Therefore, our work constitutes the first step towards studying quantum nonlinear effect in circuit electromechanics.

  1. OBSERVATION OF STRONG - STRONG AND OTHER BEAM - BEAM EFFECTS IN RHIC.

    SciTech Connect

    Fischer, W; Brennan, J M; Cameron, P; Connolly, R; Montag, C; Peggs, S; Pilat, F; Ptitsyn, V; Tepikian, S; Trbojevic, D; Van Zeijts, J

    2003-05-12

    RHIC is currently the only hadron collider in which strong-strong beam-beam effects can be seen. For the first time, coherent beam-beam modes were observed in a bunched beam hadron collider. Other beam-beam effects in RHIC were observed in operation and in dedicated experiments with gold ions, deuterons and protons. Observations include measurements of beam-beam induced tune shifts, lifetime and emittance growth measurements with and without beam-beam interaction, and background rates as a function of tunes. During ramps unequal radio frequencies in the two rings cause the crossing points to move longitudinally. Thus bunches experience beam-beam interactions only in intervals and the tunes are modulated. In this article we summarize the most important beam-beam observations made so far.

  2. Chiral spiral induced by a strong magnetic field

    NASA Astrophysics Data System (ADS)

    Abuki, Hiroaki

    2016-11-01

    We study the modification of the chiral phase structure of QCD due to an external magnetic field. We first demonstrate how the effect of magnetic field can systematically be incorporated into a generalized Ginzburg-Landau framework. We then analyze the phase structure in the vicinity of the chiral critical point. In the chiral limit, the effect is found to be so drastic that it brings a "continent" of chiral spiral in the phase diagram, by which the chiral tricritical point is totally washed out. This is the case no matter how small the intensity of magnetic field is. On the other hand, the current quark mass protects the chiral critical point from a weak magnetic field. However, the critical point will eventually be covered by the chiral spiral phase as the magnetic field grows.

  3. Nematic twist cell: Strong chirality induced at the surfaces

    NASA Astrophysics Data System (ADS)

    Lin, Tzu-Chieh; Nemitz, Ian R.; Pendery, Joel S.; Schubert, Christopher P. J.; Lemieux, Robert P.; Rosenblatt, Charles

    2013-04-01

    A nematic twist cell having a thickness gradient was filled with a mixture containing a configurationally achiral liquid crystal (LC) and chiral dopant. A chiral-based linear electrooptic effect was observed on application of an ac electric field. This "electroclinic effect" varied monotonically with d, changing sign at d =d0 where the chiral dopant exactly compensated the imposed twist. The results indicate that a significant chiral electrooptic effect always exists near the surfaces of a twist cell containing molecules that can be conformationally deracemized. Additionally, this approach can be used to measure the helical twisting power (HTP) of a chiral dopant in a liquid crystal.

  4. Confinement-induced super strong PS/MWNT composite nanofibers

    NASA Astrophysics Data System (ADS)

    Ji, Y.; Li, C.; Wang, G.; Koo, J.; Ge, S.; Li, B.; Jiang, J.; Herzberg, B.; Klein, T.; Chen, S.; Sokolov, J. C.; Rafailovich, M. H.

    2008-12-01

    Shear Modulation Force Microscopy (SMFM) together with the Atomic Force Microscopy (AFM) based three-point bending technique were used to measure the mechanical properties of electrospun polymers and polymer nanocomposite fibers. Both techniques showed that the moduli of the fibers increased significantly with decreasing fiber diameter. We attributed this enhancement to the orientation of polymer chains which occurs during the electrospinning process. We then predicted, and confirmed experimentally, that the phenomenon scales with Rg rather than with the absolute fiber diameter and can propagate radially for large distances (~20Rg) into the fiber interior. The inclusion of nanotubes into the fibers further enhanced the orientation by introducing additional surfaces. The additional increase in modulus (more than an order of magnitude) could then be explained by the same model and scaled on a universal curve.

  5. Strong Winds over the Keel

    NASA Astrophysics Data System (ADS)

    2009-02-01

    The latest ESO image reveals amazing detail in the intricate structures of one of the largest and brightest nebulae in the sky, the Carina Nebula (NGC 3372), where strong winds and powerful radiation from an armada of massive stars are creating havoc in the large cloud of dust and gas from which the stars were born. ESO PR Photo 05a/09 The Carina Nebula ESO PR Video 05a/09 Pan over the Carina Nebula ESO PR Video 05b/09 Carina Nebula Zoom-in The large and beautiful image displays the full variety of this impressive skyscape, spattered with clusters of young stars, large nebulae of dust and gas, dust pillars, globules, and adorned by one of the Universe's most impressive binary stars. It was produced by combining exposures through six different filters from the Wide Field Imager (WFI), attached to the 2.2 m ESO/MPG telescope at ESO's La Silla Observatory, in Chile. The Carina Nebula is located about 7500 light-years away in the constellation of the same name (Carina; the Keel). Spanning about 100 light-years, it is four times larger than the famous Orion Nebula and far brighter. It is an intensive star-forming region with dark lanes of cool dust splitting up the glowing nebula gas that surrounds its many clusters of stars. The glow of the Carina Nebula comes mainly from hot hydrogen basking in the strong radiation of monster baby stars. The interaction between the hydrogen and the ultraviolet light results in its characteristic red and purple colour. The immense nebula contains over a dozen stars with at least 50 to 100 times the mass of our Sun. Such stars have a very short lifespan, a few million years at most, the blink of an eye compared with the Sun's expected lifetime of ten billion years. One of the Universe's most impressive stars, Eta Carinae, is found in the nebula. It is one of the most massive stars in our Milky Way, over 100 times the mass of the Sun and about four million times brighter, making it the most luminous star known. Eta Carinae is highly

  6. Promoting Strong Written Communication Skills

    NASA Astrophysics Data System (ADS)

    Narayanan, M.

    2015-12-01

    The reason that an improvement in the quality of technical writing is still needed in the classroom is due to the fact that universities are facing challenging problems not only on the technological front but also on the socio-economic front. The universities are actively responding to the changes that are taking place in the global consumer marketplace. Obviously, there are numerous benefits of promoting strong written communication skills. They can be summarized into the following six categories. First, and perhaps the most important: The University achieves learner satisfaction. The learner has documented verbally, that the necessary knowledge has been successfully acquired. This results in learner loyalty that in turn will attract more qualified learners.Second, quality communication lowers the cost per pupil, consequently resulting in increased productivity backed by a stronger economic structure and forecast. Third, quality communications help to improve the cash flow and cash reserves of the university. Fourth, having high quality communication enables the university to justify the need for high costs of tuition and fees. Fifth, better quality in written communication skills result in attracting top-quality learners. This will lead to happier and satisfied learners, not to mention greater prosperity for the university as a whole. Sixth, quality written communication skills result in reduced complaints, thus meaning fewer hours spent on answering or correcting the situation. The University faculty and staff are thus able to devote more time on scholarly activities, meaningful research and productive community service. References Boyer, Ernest L. (1990). Scholarship reconsidered: Priorities of the Professorate.Princeton, NJ: Carnegie Foundation for the Advancement of Teaching. Hawkins, P., & Winter, J. (1997). Mastering change: Learning the lessons of the enterprise.London: Department for Education and Employment. Buzzel, Robert D., and Bradley T. Gale. (1987

  7. The strong maximum principle revisited

    NASA Astrophysics Data System (ADS)

    Pucci, Patrizia; Serrin, James

    In this paper we first present the classical maximum principle due to E. Hopf, together with an extended commentary and discussion of Hopf's paper. We emphasize the comparison technique invented by Hopf to prove this principle, which has since become a main mathematical tool for the study of second order elliptic partial differential equations and has generated an enormous number of important applications. While Hopf's principle is generally understood to apply to linear equations, it is in fact also crucial in nonlinear theories, such as those under consideration here. In particular, we shall treat and discuss recent generalizations of the strong maximum principle, and also the compact support principle, for the case of singular quasilinear elliptic differential inequalities, under generally weak assumptions on the quasilinear operators and the nonlinearities involved. Our principal interest is in necessary and sufficient conditions for the validity of both principles; in exposing and simplifying earlier proofs of corresponding results; and in extending the conclusions to wider classes of singular operators than previously considered. The results have unexpected ramifications for other problems, as will develop from the exposition, e.g. two point boundary value problems for singular quasilinear ordinary differential equations (Sections 3 and 4); the exterior Dirichlet boundary value problem (Section 5); the existence of dead cores and compact support solutions, i.e. dead cores at infinity (Section 7); Euler-Lagrange inequalities on a Riemannian manifold (Section 9); comparison and uniqueness theorems for solutions of singular quasilinear differential inequalities (Section 10). The case of p-regular elliptic inequalities is briefly considered in Section 11.

  8. Confinining properties of QCD in strong magnetic backgrounds

    NASA Astrophysics Data System (ADS)

    Bonati, Claudio; D'Elia, Massimo; Mariti, Marco; Mesiti, Michele; Negro, Francesco; Rucci, Andrea; Sanfilippo, Francesco

    2017-03-01

    Strong magnetic backgrounds are known to modify QCD properties at a nonperturbative level. We discuss recent lattice results, obtained for Nf = 2 + 1 QCD with physical quark masses, concerning in particular the modifications and the anisotropies induced at the level of the static quark-antiquark potential, both at zero and finite temperature.

  9. Quantum dynamics in strong fluctuating fields

    NASA Astrophysics Data System (ADS)

    Goychuk, Igor; Hänggi, Peter

    A large number of multifaceted quantum transport processes in molecular systems and physical nanosystems, such as e.g. nonadiabatic electron transfer in proteins, can be treated in terms of quantum relaxation processes which couple to one or several fluctuating environments. A thermal equilibrium environment can conveniently be modelled by a thermal bath of harmonic oscillators. An archetype situation provides a two-state dissipative quantum dynamics, commonly known under the label of a spin-boson dynamics. An interesting and nontrivial physical situation emerges, however, when the quantum dynamics evolves far away from thermal equilibrium. This occurs, for example, when a charge transferring medium possesses nonequilibrium degrees of freedom, or when a strong time-dependent control field is applied externally. Accordingly, certain parameters of underlying quantum subsystem acquire stochastic character. This may occur, for example, for the tunnelling coupling between the donor and acceptor states of the transferring electron, or for the corresponding energy difference between electronic states which assume via the coupling to the fluctuating environment an explicit stochastic or deterministic time-dependence. Here, we review the general theoretical framework which is based on the method of projector operators, yielding the quantum master equations for systems that are exposed to strong external fields. This allows one to investigate on a common basis, the influence of nonequilibrium fluctuations and periodic electrical fields on those already mentioned dynamics and related quantum transport processes. Most importantly, such strong fluctuating fields induce a whole variety of nonlinear and nonequilibrium phenomena. A characteristic feature of such dynamics is the absence of thermal (quantum) detailed balance.ContentsPAGE1. Introduction5262. Quantum dynamics in stochastic fields531 2.1. Stochastic Liouville equation531 2.2. Non-Markovian vs. Markovian discrete

  10. Atoms and Molecules in Strong Magnetic Fields

    NASA Astrophysics Data System (ADS)

    Schmelcher, P.; Cederbaum, L. S.

    Selected topics on atoms and molecules in strong magnetic fields are reviewed. The enormous progress made for the hydrogen atom in a magnetic field and its impact on different areas like, for example, modern semi-classics and dynamics of non-integrable systems as well as laser spectroscopy are outlined. Due to the non-separability of the centre of mass and electronic motion of atoms/molecules in magnetic fields a variety of two-body phenomena can be observed in highly excited systems. Examples are the classical diffusion of the centre of mass and the giant dipole states for crossed fields. For ions energy transfer processes lead to the so-called self-ionisation process. Magnetically induced crossovers for the ground states of atoms are investigated. The increasing complexity of the ground state behaviour of magnetically dressed multi-electron atoms due to changes of the spin polarisation as well as spatial orbitals is demonstrated. For molecules, both fundamental aspects as well as the electronic structure of few-electron diatomics are reviewed.

  11. Evidence for a glassy state in strongly driven carbon

    NASA Astrophysics Data System (ADS)

    Brown, C. R. D.; Gericke, D. O.; Cammarata, M.; Cho, B. I.; Döppner, T.; Engelhorn, K.; Förster, E.; Fortmann, C.; Fritz, D.; Galtier, E.; Glenzer, S. H.; Harmand, M.; Heimann, P.; Kugland, N. L.; Lamb, D. Q.; Lee, H. J.; Lee, R. W.; Lemke, H.; Makita, M.; Moinard, A.; Murphy, C. D.; Nagler, B.; Neumayer, P.; Plagemann, K.-U.; Redmer, R.; Riley, D.; Rosmej, F. B.; Sperling, P.; Toleikis, S.; Vinko, S. M.; Vorberger, J.; White, S.; White, T. G.; Wünsch, K.; Zastrau, U.; Zhu, D.; Tschentscher, T.; Gregori, G.

    2014-06-01

    Here, we report results of an experiment creating a transient, highly correlated carbon state using a combination of optical and x-ray lasers. Scattered x-rays reveal a highly ordered state with an electrostatic energy significantly exceeding the thermal energy of the ions. Strong Coulomb forces are predicted to induce nucleation into a crystalline ion structure within a few picoseconds. However, we observe no evidence of such phase transition after several tens of picoseconds but strong indications for an over-correlated fluid state. The experiment suggests a much slower nucleation and points to an intermediate glassy state where the ions are frozen close to their original positions in the fluid.

  12. Evidence for a glassy state in strongly driven carbon.

    PubMed

    Brown, C R D; Gericke, D O; Cammarata, M; Cho, B I; Döppner, T; Engelhorn, K; Förster, E; Fortmann, C; Fritz, D; Galtier, E; Glenzer, S H; Harmand, M; Heimann, P; Kugland, N L; Lamb, D Q; Lee, H J; Lee, R W; Lemke, H; Makita, M; Moinard, A; Murphy, C D; Nagler, B; Neumayer, P; Plagemann, K-U; Redmer, R; Riley, D; Rosmej, F B; Sperling, P; Toleikis, S; Vinko, S M; Vorberger, J; White, S; White, T G; Wünsch, K; Zastrau, U; Zhu, D; Tschentscher, T; Gregori, G

    2014-06-09

    Here, we report results of an experiment creating a transient, highly correlated carbon state using a combination of optical and x-ray lasers. Scattered x-rays reveal a highly ordered state with an electrostatic energy significantly exceeding the thermal energy of the ions. Strong Coulomb forces are predicted to induce nucleation into a crystalline ion structure within a few picoseconds. However, we observe no evidence of such phase transition after several tens of picoseconds but strong indications for an over-correlated fluid state. The experiment suggests a much slower nucleation and points to an intermediate glassy state where the ions are frozen close to their original positions in the fluid.

  13. Evidence for a glassy state in strongly driven carbon

    SciTech Connect

    Brown, C. R. D.; Gericke, D. O.; Cammarata, M.; Cho, B. I.; Gwangju Inst. of Science and Technology, Gwangju; Inst. for Basic Science, Gwangju ; Döppner, T.; Engelhorn, K.; Förster, E.; Fortmann, C.; Fritz, D.; Galtier, E.; Glenzer, S. H.; Harmand, M.; Heimann, P.; Kugland, N. L.; Lamb, D. Q.; Lee, H. J.; Lee, R. W.; Lemke, H.; Makita, M.; Moinard, A.; Murphy, C. D.; Nagler, B.; Neumayer, P.; Plagemann, K. -U.; Redmer, R.; Riley, D.; Rosmej, F. B.; Sperling, P.; Toleikis, S.; Vinko, S. M.; Vorberger, J.; White, S.; White, T. G.; Wünsch, K.; Zastrau, U.; Zhu, D.; Tschentscher, T.; Gregori, G.

    2014-06-09

    Here, we report results of an experiment creating a transient, highly correlated carbon state using a combination of optical and x-ray lasers. Scattered x-rays reveal a highly ordered state with an electrostatic energy significantly exceeding the thermal energy of the ions. Strong Coulomb forces are predicted to induce nucleation into a crystalline ion structure within a few picoseconds. However, we observe no evidence of such phase transition after several tens of picoseconds but strong indications for an over-correlated fluid state. The experiment suggests a much slower nucleation and points to an intermediate glassy state where the ions are frozen close to their original positions in the fluid.

  14. Mixtures of Strongly Interacting Bosons in Optical Lattices

    SciTech Connect

    Buonsante, P.; Penna, V.; Giampaolo, S. M.; Illuminati, F.; Vezzani, A.

    2008-06-20

    We investigate the properties of strongly interacting heteronuclear boson-boson mixtures loaded in realistic optical lattices, with particular emphasis on the physics of interfaces. In particular, we numerically reproduce the recent experimental observation that the addition of a small fraction of {sup 41}K induces a significant loss of coherence in {sup 87}Rb, providing a simple explanation. We then investigate the robustness against the inhomogeneity typical of realistic experimental realizations of the glassy quantum emulsions recently predicted to occur in strongly interacting boson-boson mixtures on ideal homogeneous lattices.

  15. 78 FR 15710 - Strong Sensitizer Guidance

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-12

    ... document is intended to clarify the ``strong sensitizer'' definition, assist manufacturers in understanding... definition of ``strong sensitizer'' found at 16 CFR 1500.3(c)(5). The Commission is proposing to revise the supplemental definition of ``strong sensitizer'' due to advancements in the science of sensitization that...

  16. Driven optical lattices as strong-field simulators

    SciTech Connect

    Arlinghaus, Stephan; Holthaus, Martin

    2010-06-15

    We argue that ultracold atoms in strongly shaken optical lattices can be subjected to conditions similar to those experienced by electrons in laser-irradiated crystalline solids, but without introducing secondary polarization effects. As a consequence, one can induce nonperturbative multiphoton-like resonances due to the mutual penetration of ac-Stark-shifted Bloch bands. These phenomena can be detected with a combination of currently available laboratory techniques.

  17. Energy Exchange in Driven Open Quantum Systems at Strong Coupling

    NASA Astrophysics Data System (ADS)

    Carrega, Matteo; Solinas, Paolo; Sassetti, Maura; Weiss, Ulrich

    2016-06-01

    The time-dependent energy transfer in a driven quantum system strongly coupled to a heat bath is studied within an influence functional approach. Exact formal expressions for the statistics of energy dissipation into the different channels are derived. The general method is applied to the driven dissipative two-state system. It is shown that the energy flows obey a balance relation, and that, for strong coupling, the interaction may constitute the major dissipative channel. Results in analytic form are presented for the particular value K =1/2 of strong Ohmic dissipation. The energy flows show interesting behaviors including driving-induced coherences and quantum stochastic resonances. It is found that the general characteristics persists for K near 1/2 .

  18. Strongly Magnetized Accretion Disks Around Black Holes

    NASA Astrophysics Data System (ADS)

    Salvesen, Greg; Armitage, Philip J.; Simon, Jacob B.; Begelman, Mitchell C.

    2017-01-01

    Recent observations are suggestive of strongly magnetized accretion disks around black holes. Performing local (shearing box) simulations of accretion disks, we investigate how a strong magnetization state can develop and persist. We demonstrate that poloidal flux is a necessary prerequisite for the sustainability of strongly magnetized accretion disks. We also show that black hole spin measurements can become unconstrained if magnetic fields provide a significant contribution to the vertical pressure support of the accretion disk atmosphere.

  19. Effect of dilute strongly pinning impurities on charge density waves

    NASA Astrophysics Data System (ADS)

    Okamoto, Jun-ichi; Millis, Andrew J.

    2015-05-01

    We study theoretically the effects of strong pinning centers on a charge density wave in the limit that the charge density wave coherence length is shorter than the average interimpurity distance. An analysis based on a Ginzburg-Landau model shows that long-range forces arising from the elastic response of the charge density wave induce a kind of collective pinning which suppresses impurity-induced phase fluctuations, leading to a long-range ordered ground state. The correlations induced by impurities are characterized by a length scale parametrically longer than the average interimpurity distance. Long-wavelength fluctuations are found to be gapped, implying the stability of the ground state. We also present Monte Carlo simulations that confirm the basic features of the analytical results.

  20. 77 FR 16131 - Establishing a White House Council on Strong Cities, Strong Communities

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-20

    ... White House Council on Strong Cities, Strong Communities By the authority vested in me as President by...: Section 1. Policy. Cities, towns, and regions across our Nation continue to face difficult economic... established the Strong Cities, Strong Communities (SC2) pilot initiative. By partnering with cities...

  1. Keeping Marriages Strong in Challenging Times

    ERIC Educational Resources Information Center

    Ober, Marci Wolff

    2009-01-01

    What makes a strong marriage anyway...? There are definite qualities that exist in healthy marriages, that is, a marriage that is defined by both partners to be "mostly" or "usually" very satisfying. This article explores these qualities and looks at what really works to make and keep marriages strong, healthy, and satisfying…

  2. On the Strong Direct Summand Conjecture

    ERIC Educational Resources Information Center

    McCullough, Jason

    2009-01-01

    In this thesis, our aim is the study the Vanishing of Maps of Tor Conjecture of Hochster and Huneke. We mainly focus on an equivalent characterization called the Strong Direct Summand Conjecture, due to N. Ranganathan. Our results are separated into three chapters. In Chapter 3, we prove special cases of the Strong Direct Summand Conjecture in…

  3. Strong diamagnetism of normal metals and superconductivity

    NASA Astrophysics Data System (ADS)

    Abramov, O. V.; Gradov, O. M.; Kyrie, A. Yu

    1992-07-01

    The theory of strong diamagnetism of metals caused by the formation of a superlattice with the period being much larger than the crystal cell size has been developed. Strong diamagnetism has been shown to be the cause of the superconductivity of metals.

  4. Seismic switch for strong motion measurement

    DOEpatents

    Harben, Philip E.; Rodgers, Peter W.; Ewert, Daniel W.

    1995-01-01

    A seismic switching device that has an input signal from an existing microseismic station seismometer and a signal from a strong motion measuring instrument. The seismic switch monitors the signal level of the strong motion instrument and passes the seismometer signal to the station data telemetry and recording systems. When the strong motion instrument signal level exceeds a user set threshold level, the seismometer signal is switched out and the strong motion signal is passed to the telemetry system. The amount of time the strong motion signal is passed before switching back to the seismometer signal is user controlled between 1 and 15 seconds. If the threshold level is exceeded during a switch time period, the length of time is extended from that instant by one user set time period.

  5. Seismic switch for strong motion measurement

    DOEpatents

    Harben, P.E.; Rodgers, P.W.; Ewert, D.W.

    1995-05-30

    A seismic switching device is described that has an input signal from an existing microseismic station seismometer and a signal from a strong motion measuring instrument. The seismic switch monitors the signal level of the strong motion instrument and passes the seismometer signal to the station data telemetry and recording systems. When the strong motion instrument signal level exceeds a user set threshold level, the seismometer signal is switched out and the strong motion signal is passed to the telemetry system. The amount of time the strong motion signal is passed before switching back to the seismometer signal is user controlled between 1 and 15 seconds. If the threshold level is exceeded during a switch time period, the length of time is extended from that instant by one user set time period. 11 figs.

  6. Strong Dietary Restrictions Protect Drosophila against Anoxia/Reoxygenation Injuries

    PubMed Central

    Vigne, Paul; Tauc, Michel; Frelin, Christian

    2009-01-01

    Background Reoxygenation of ischemic tissues is a major factor that determines the severity of cardiovascular diseases. This paper describes the consequences of anoxia/reoxygenation (A/R) stresses on Drosophila, a useful, anoxia tolerant, model organism. Methodology/Principal Findings Newly emerged adult male flies were exposed to anoxic conditions (<1% O2) for 1 to 6 hours, reoxygenated and their survival was monitored. Results A/R stresses induced a transient increase in mortality which peaked at the time of reoxygenation. Then flies recovered low mortality rates similar to those of control flies. A/R induced mortality was strongly dependent on dietary conditions during the 48 h that preceded anoxia. Well fed flies were anoxia sensitive. Strong dietary restrictions and starvation conditions protected flies against A/R injuries. The tolerance to anoxia was associated to large decreases in glycogen, protein, and ATP contents. During anoxia, anoxia tolerant flies produced more lactate, less phosphate and they maintained more stable ATP levels than anoxia sensitive flies. Moderate dietary restrictions, which increased the longevity of normoxic flies, did not promote resistance to A/R stresses. Diet dependent A/R injuries were still observed in sima loss of function mutants and they were insensitive to dietary rapamycin or resveratrol. AICAR (5-aminoimidazole-4-carboxamide-1-beta-D-ribosefuranoside), an activator AMP kinase decreased A/R injuries. Mutants in the insulin signalling pathway were more anoxia tolerant in a fed state. Conclusion/Significance Long A/R stresses induce a transient increase in mortality in Drosophila. This mortality is highly dependent on dietary conditions prior to the stress. Strong dietary restrictions and starvation conditions protect flies against A/R injuries, probably by inducing a major remodelling of energy metabolism. The results also indicate that mechanistically different responses develop in response to dietary restrictions of

  7. Puerto Rico Strong Motion Seismic Network

    NASA Astrophysics Data System (ADS)

    Huerta-Lopez, C. I.; Martínez-Cruzado, J. A.; Martínez-Pagan, J.; Santana-Torres, E. X.; Torres-O, D. M.

    2014-12-01

    The Puerto Rico Strong Motion Seismic Network is currently in charge of the operation of: (i) free-field (ff) strong motion stations, (ii) instrumented structures (STR) (Dams, Bridges, Buildings), and (iii) the data acquisition/monitoring and analysis of earthquakes considered strong from the point of view of their intensity and magnitude. All these instruments are deployed in the Puerto Rico Island (PRI), US-, and British-Virgin Islands (BVI), and Dominican Republic (DR). The Puerto Rico Island and the Caribbean region have high potential to be affected by earthquakes that could be catastrophic for the area. The Puerto Rico Strong Motion Seismic Network (actually Puerto Rico Strong Motion Program, PRSMP) has grown since 1970's from 7 ff strong motion stations and one instrumented building with analog accelerographs to 111 ff strong motion stations and 16 instrumented buildings with digital accelerographs: PRI: 88 ff, 16 STR., DR: 13 ff, BVI: 5 ff, 2 STR collecting data via IP (internet), DU (telephone), and stand alone stations The current stage of the PRSMP seismic network, the analysis of moderate earthquakes that were recorded and/or occurred on the island, results of the intensity distribution of selected earthquakes, as well as results of dynamic parameter identification of some of the instrumented structures are here presented.

  8. Strong-field ionization via a high-order Coulomb-corrected strong-field approximation

    NASA Astrophysics Data System (ADS)

    Klaiber, Michael; Daněk, Jiří; Yakaboylu, Enderalp; Hatsagortsyan, Karen Z.; Keitel, Christoph H.

    2017-02-01

    Signatures of the Coulomb corrections in the photoelectron momentum distribution during laser-induced ionization of atoms or ions in tunneling and multiphoton regimes are investigated analytically in the case of a one-dimensional problem. A high-order Coulomb-corrected strong-field approximation is applied, where the exact continuum state in the S matrix is approximated by the eikonal Coulomb-Volkov state including the second-order corrections to the eikonal. Although without high-order corrections our theory coincides with the known analytical R -matrix (ARM) theory, we propose a simplified procedure for the matrix element derivation. Rather than matching the eikonal Coulomb-Volkov wave function with the bound state as in the ARM theory to remove the Coulomb singularity, we calculate the matrix element via the saddle-point integration method by time as well as by coordinate, and in this way avoiding the Coulomb singularity. The momentum shift in the photoelectron momentum distribution with respect to the ARM theory due to high-order corrections is analyzed for tunneling and multiphoton regimes. The relation of the quantum corrections to the tunneling delay time is discussed.

  9. Dual field theory of strong interactions

    SciTech Connect

    Akers, D.

    1987-07-01

    A dual field theory of strong interactions is derived from a Lagrangian of the Yang-Mills and Higgs fields. The existence of a magnetic monopole of mass 2397 MeV and Dirac charge g = (137/2)e is incorporated into the theory. Unification of the strong, weak, and electromagnetic forces is shown to converge at the mass of the intermediate vector boson W/sup +/-/. The coupling constants of the strong and weak interactions are derived in terms of the fine-structure constant ..cap alpha.. = 1/137.

  10. Strong photoassociation in a degenerate fermi gas

    NASA Astrophysics Data System (ADS)

    Rvachov, Timur; Jamison, Alan; Jing, Li; Son, Hyungmok; Ebadi, Sepehr; Jiang, Yijun; Zwierlein, Martin; Ketterle, Wolfgang

    2016-05-01

    Despite many studies there remain open questions about strong photoassociation in ultracold gases. We study the effects of strong photoassociation in ultracold fermions. Photoassociation occurs only at short range and thus can be used as a tool to probe and control the two-body correlation function in an interacting many-body system. We study the effects of strong photoassociation in 6 Li, the onset of saturation, and its effects on spin polarized and interacting spin-mixtures. This work was funded by the NSF, ARO-MURI, SAMSUNG, and NSERC.

  11. Radio-Frequency Spectroscopy of a Strongly Interacting Two-Dimensional Fermi Gas

    SciTech Connect

    Froehlich, Bernd; Feld, Michael; Vogt, Enrico; Koschorreck, Marco; Koehl, Michael; Zwerger, Wilhelm

    2011-03-11

    We realize and study a strongly interacting two-component atomic Fermi gas confined to two dimensions in an optical lattice. Using radio-frequency spectroscopy we measure the interaction energy of the strongly interacting gas. We observe the confinement-induced Feshbach resonance on the attractive side of the 3D Feshbach resonance and find the existence of confinement-induced molecules in very good agreement with theoretical predictions.

  12. XUV Transient Absorption of Strong-Field Ionized Ferrocene

    NASA Astrophysics Data System (ADS)

    Chatterley, Adam S.; Lackner, Florian; Neumark, Daniel M.; Leone, Stephen R.; Gessner, Oliver

    2015-05-01

    Femtosecond extreme ultraviolet (XUV) transient absorption experiments are underway to study the dynamics of ferrocene following strong field ionization. Ferrocene is a textbook organometallic compound, composed of an iron atom sandwiched between two aromatic organic rings. An intense infrared (IR, 790 nm) pump pulse is used to ionize the ferrocene molecules. Femtosecond XUV pulses, created by high harmonic generation (HHG) are used to probe the induced dynamics. Iron 3p inner-shell to valence transitions (M edge, 50 eV strong-field induced molecular dynamics from the perspective of the metal center. We will induce dissociation dynamics at high field intensities and use lower IR intensities to study dynamics of electronically and/or vibrationally excited ferrocene cations. Preliminary results will be presented, demonstrating current progress of XUV transient absorption experiments on moderately large molecular systems.

  13. Strongly magnetized accretion discs require poloidal flux

    NASA Astrophysics Data System (ADS)

    Salvesen, Greg; Armitage, Philip J.; Simon, Jacob B.; Begelman, Mitchell C.

    2016-08-01

    Motivated by indirect observational evidence for strongly magnetized accretion discs around black holes, and the novel theoretical properties of such solutions, we investigate how a strong magnetization state can develop and persist. To this end, we perform local simulations of accretion discs with an initially purely toroidal magnetic field of equipartition strength. We demonstrate that discs with zero net vertical magnetic flux and realistic boundary conditions cannot sustain a strong toroidal field. However, a magnetic pressure-dominated disc can form from an initial configuration with a sufficient amount of net vertical flux and realistic boundary conditions. Our results suggest that poloidal flux is a necessary prerequisite for the sustainability of strongly magnetized accretion discs.

  14. Green jobs and a strong middle class.

    PubMed

    Podesta, John D

    2009-01-01

    Green jobs are critical to building a strong middle class, and millions of green jobs can be created through energy efficiency. The models already exist for this work, but we need sustained investment to bring them to scale.

  15. Electronic spectra of strongly modulated aperiodic structures

    SciTech Connect

    Barache, D. ); Luck, J.M. )

    1994-06-01

    We consider the tight-binding Hamiltonian on strongly modulated aperiodic chains (e.g., quasiperiodic, self-similar, random). The site energies are distributed according to a given binary sequence ([ital V][sub [ital n

  16. Quantum Strong Coupling with Protein Vibrational Modes.

    PubMed

    Vergauwe, Robrecht M A; George, Jino; Chervy, Thibault; Hutchison, James A; Shalabney, Atef; Torbeev, Vladimir Y; Ebbesen, Thomas W

    2016-10-07

    In quantum electrodynamics, matter can be hybridized to confined optical fields by a process known as light-matter strong coupling. This gives rise to new hybrid light-matter states and energy levels in the coupled material, leading to modified physical and chemical properties. Here, we report for the first time the strong coupling of vibrational modes of proteins with the vacuum field of a Fabry-Perot mid-infrared cavity. For two model systems, poly(l-glutamic acid) and bovine serum albumin, strong coupling is confirmed by the anticrossing in the dispersion curve, the square root dependence on the concentration, and a vacuum Rabi splitting that is larger than the cavity and vibration line widths. These results demonstrate that strong coupling can be applied to the study of proteins with many possible applications including the elucidation of the role of vibrational dynamics in enzyme catalysis and in H/D exchange experiments.

  17. Diffusive Mixing in Strongly Coupled Plasmas

    NASA Astrophysics Data System (ADS)

    Diaw, Abdourahmane; Murillo, Michael

    2016-10-01

    A multispecies hydrodynamic model based on moments of the Born-Bogolyubov-Green-Kirkwood-Yvon (BBGKY) hierarchy is developed for physical conditions relevant to astrophysical plasmas. The modified transport equations incorporate strong correlations through a density functional theory closure, while fluctuations enters through a mixture BGK operator. This model extends the usual Burgers equations for a dilute gas to strongly coupled and isothermal plasmas mixtures. The diffusive currents for these strongly coupled plasmas is self-consistently derived. The settling of impurities and its impact on cooling of white dwarfs and neutron stars can be greatly affected by strong Coulomb coupling, which we show can be quantified using the direct-correlation function. This work was supported by the Air Force Office of Scientific Research (Grant No. FA9550-12-1-0344).

  18. Attract Academically Strong Students: Market the Faculty.

    ERIC Educational Resources Information Center

    Rickard, Charles E.; Walters, James C.

    1984-01-01

    Presents a marketing strategy to assist admissions personnel in recruiting academically strong students to colleges and universities. Discusses the importance of institutional prestige and faculty achievement as well as the need to involve faculty in student recruitment. (JAC)

  19. Thermalization of strongly disordered nonlinear chains.

    PubMed

    Kottos, Tsampikos; Shapiro, Boris

    2011-06-01

    Thermalization of systems described by the discrete nonlinear Schrödinger equation, in the strong disorder limit, is investigated both theoretically and numerically. We show that introducing correlations in the disorder potential, while keeping the "effective" disorder fixed (as measured by the localization properties of wave-packet dynamics), strongly facilitates the thermalization process and leads to a standard grand canonical distribution of the probability norms associated with each site.

  20. Evolutionary games on cycles with strong selection.

    PubMed

    Altrock, P M; Traulsen, A; Nowak, M A

    2017-02-01

    Evolutionary games on graphs describe how strategic interactions and population structure determine evolutionary success, quantified by the probability that a single mutant takes over a population. Graph structures, compared to the well-mixed case, can act as amplifiers or suppressors of selection by increasing or decreasing the fixation probability of a beneficial mutant. Properties of the associated mean fixation times can be more intricate, especially when selection is strong. The intuition is that fixation of a beneficial mutant happens fast in a dominance game, that fixation takes very long in a coexistence game, and that strong selection eliminates demographic noise. Here we show that these intuitions can be misleading in structured populations. We analyze mean fixation times on the cycle graph under strong frequency-dependent selection for two different microscopic evolutionary update rules (death-birth and birth-death). We establish exact analytical results for fixation times under strong selection and show that there are coexistence games in which fixation occurs in time polynomial in population size. Depending on the underlying game, we observe inherence of demographic noise even under strong selection if the process is driven by random death before selection for birth of an offspring (death-birth update). In contrast, if selection for an offspring occurs before random removal (birth-death update), then strong selection can remove demographic noise almost entirely.

  1. Evolutionary games on cycles with strong selection

    NASA Astrophysics Data System (ADS)

    Altrock, P. M.; Traulsen, A.; Nowak, M. A.

    2017-02-01

    Evolutionary games on graphs describe how strategic interactions and population structure determine evolutionary success, quantified by the probability that a single mutant takes over a population. Graph structures, compared to the well-mixed case, can act as amplifiers or suppressors of selection by increasing or decreasing the fixation probability of a beneficial mutant. Properties of the associated mean fixation times can be more intricate, especially when selection is strong. The intuition is that fixation of a beneficial mutant happens fast in a dominance game, that fixation takes very long in a coexistence game, and that strong selection eliminates demographic noise. Here we show that these intuitions can be misleading in structured populations. We analyze mean fixation times on the cycle graph under strong frequency-dependent selection for two different microscopic evolutionary update rules (death-birth and birth-death). We establish exact analytical results for fixation times under strong selection and show that there are coexistence games in which fixation occurs in time polynomial in population size. Depending on the underlying game, we observe inherence of demographic noise even under strong selection if the process is driven by random death before selection for birth of an offspring (death-birth update). In contrast, if selection for an offspring occurs before random removal (birth-death update), then strong selection can remove demographic noise almost entirely.

  2. Theoretical prediction of a strongly correlated Dirac metal.

    PubMed

    Mazin, I I; Jeschke, Harald O; Lechermann, Frank; Lee, Hunpyo; Fink, Mario; Thomale, Ronny; Valentí, Roser

    2014-07-01

    Recently, the most intensely studied objects in the electronic theory of solids have been strongly correlated systems and graphene. However, the fact that the Dirac bands in graphene are made up of sp(2) electrons, which are subject to neither strong Hubbard repulsion U nor strong Hund's rule coupling J, creates certain limitations in terms of novel, interaction-induced physics that could be derived from Dirac points. Here we propose GaCu3(OH)6Cl2 (Ga-substituted herbertsmithite) as a correlated Dirac-Kagome metal combining Dirac electrons, strong interactions and frustrated magnetic interactions. Using density functional theory, we calculate its crystallographic and electronic properties, and observe that it has symmetry-protected Dirac points at the Fermi level. Its many-body physics is diverse, with possible charge, magnetic and superconducting instabilities. Through a combination of various many-body methods we study possible symmetry-lowering phase transitions such as Mott-Hubbard, charge or magnetic ordering, and unconventional superconductivity, which in this compound assumes an f-wave symmetry.

  3. Evidence for a glassy state in strongly driven carbon

    DOE PAGES

    Brown, C. R. D.; Gericke, D. O.; Cammarata, M.; ...

    2014-06-09

    Here, we report results of an experiment creating a transient, highly correlated carbon state using a combination of optical and x-ray lasers. Scattered x-rays reveal a highly ordered state with an electrostatic energy significantly exceeding the thermal energy of the ions. Strong Coulomb forces are predicted to induce nucleation into a crystalline ion structure within a few picoseconds. However, we observe no evidence of such phase transition after several tens of picoseconds but strong indications for an over-correlated fluid state. The experiment suggests a much slower nucleation and points to an intermediate glassy state where the ions are frozen closemore » to their original positions in the fluid.« less

  4. Robust mesoscopic superposition of strongly correlated ultracold atoms

    SciTech Connect

    Hallwood, David W.; Ernst, Thomas; Brand, Joachim

    2010-12-15

    We propose a scheme to create coherent superpositions of annular flow of strongly interacting bosonic atoms in a one-dimensional ring trap. The nonrotating ground state is coupled to a vortex state with mesoscopic angular momentum by means of a narrow potential barrier and an applied phase that originates from either rotation or a synthetic magnetic field. We show that superposition states in the Tonks-Girardeau regime are robust against single-particle loss due to the effects of strong correlations. The coupling between the mesoscopically distinct states scales much more favorably with particle number than in schemes relying on weak interactions, thus making particle numbers of hundreds or thousands feasible. Coherent oscillations induced by time variation of parameters may serve as a 'smoking gun' signature for detecting superposition states.

  5. Atom-Pair Kinetics with Strong Electric-Dipole Interactions.

    PubMed

    Thaicharoen, N; Gonçalves, L F; Raithel, G

    2016-05-27

    Rydberg-atom ensembles are switched from a weakly to a strongly interacting regime via adiabatic transformation of the atoms from an approximately nonpolar into a highly dipolar quantum state. The resultant electric dipole-dipole forces are probed using a device akin to a field ion microscope. Ion imaging and pair-correlation analysis reveal the kinetics of the interacting atoms. Dumbbell-shaped pair-correlation images demonstrate the anisotropy of the binary dipolar force. The dipolar C_{3} coefficient, derived from the time dependence of the images, agrees with the value calculated from the permanent electric-dipole moment of the atoms. The results indicate many-body dynamics akin to disorder-induced heating in strongly coupled particle systems.

  6. Strong anisotropic thermal conductivity of monolayer WTe2

    NASA Astrophysics Data System (ADS)

    Ma, Jinlong; Chen, Yani; Han, Zheng; Li, Wu

    2016-12-01

    Tungsten ditelluride (WTe2) has attracted increasing attention due to its large magnetoresistance and pressure-induced superconductivity. In this work, we investigate the thermal conductivity (κ) of monolayer WTe2 by performing first-principles calculations, and find strong anisotropic κ with predicted room-temperature values of 9 and 20 W m-1 K-1 along two principal lattice directions, respectively. Such strong anisotropy suggests the importance of orientation when engineering thermal-related applications based on WTe2. The anisotropy of κ is attributed to the in-plane linear acoustic phonon branches, while the out-of-plane quadratic acoustic phonon branch is almost isotropic. The size dependence of κ shows that the size effect can persists up to 10 μm, and the anisotropy decreases with decreasing sample size due to the suppression of low-frequency anisotropic phonons by boundary scattering.

  7. Attosecond Electron Wave Packet Dynamics in Strong Laser Fields

    SciTech Connect

    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.

    2005-07-01

    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 ({approx}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.

  8. Vortex creep and thermal depinning within strong pinning theory

    NASA Astrophysics Data System (ADS)

    Willa, Roland; Buchacek, Martin; Geshkenbein, Vadim B.; Blatter, Gianni

    Vortex pinning in type-II superconductors can occur through the collective action of many pins (weak collective pinning scenario) or through plastic deformations induced by a low density of defects (strong pinning scenario). For the latter case, a new formalism has recently be developed to provide a quantitative link between the microscopic pinning landscape and experimentally accessible quantities describing pinning on a macroscopic level. Examples are the critical current density jc, the I- V characteristics, or the ac Campbell length λC. Inspired by the original work of Larkin and Brazovskii on density wave pinning, we have extended the strong pinning formalism to account for thermal depinning of flux lines and vortex creep.

  9. Evidence for a glassy state in strongly driven carbon

    PubMed Central

    Brown, C. R. D.; Gericke, D. O.; Cammarata, M.; Cho, B. I.; Döppner, T.; Engelhorn, K.; Förster, E.; Fortmann, C.; Fritz, D.; Galtier, E.; Glenzer, S. H.; Harmand, M.; Heimann, P.; Kugland, N. L.; Lamb, D. Q.; Lee, H. J.; Lee, R. W.; Lemke, H.; Makita, M.; Moinard, A.; Murphy, C. D.; Nagler, B.; Neumayer, P.; Plagemann, K.-U.; Redmer, R.; Riley, D.; Rosmej, F. B.; Sperling, P.; Toleikis, S.; Vinko, S. M.; Vorberger, J.; White, S.; White, T. G.; Wünsch, K.; Zastrau, U.; Zhu, D.; Tschentscher, T.; Gregori, G.

    2014-01-01

    Here, we report results of an experiment creating a transient, highly correlated carbon state using a combination of optical and x-ray lasers. Scattered x-rays reveal a highly ordered state with an electrostatic energy significantly exceeding the thermal energy of the ions. Strong Coulomb forces are predicted to induce nucleation into a crystalline ion structure within a few picoseconds. However, we observe no evidence of such phase transition after several tens of picoseconds but strong indications for an over-correlated fluid state. The experiment suggests a much slower nucleation and points to an intermediate glassy state where the ions are frozen close to their original positions in the fluid. PMID:24909903

  10. Studies of Strong Langmuir Turbulence at the HAARP Ionospheric Observatory

    NASA Astrophysics Data System (ADS)

    Sheerin, J. P.; Bacon, M. E.; Gerres, J. M.; Watkins, B. J.; Bristow, W. A.; Oyama, S. I.; Heinselman, C. J.

    2008-11-01

    High power HF transmitters have induced a number of plasma instabilities in the interaction region of overdense ionospheric plasma. We report results from a series of such experiments using over one gigawatt of HF power (ERP) in comprehensive studies of strong Langmuir turbulence (SLT) and particle acceleration at the HAARP Observatory, Gakona, Alaska. Among the effects observed and studied are: SLT spectra including the outshifted plasma line or free-mode, appearance of a short timescale ponderomotive overshoot effect, collapse, cascade and co-existing spectra, control of artificial field-aligned irregularities (AFAI), the aspect angle dependence of the plasma line, and suprathermal electrons. We explore the observed magnetic-zenith effect of enhanced turbulence backscatter with the HF pump wave directed up the field line. We have discovered a second region of strong interaction displaced southward of the primary HF interaction region. Experimental results are compared to previous high latitude experiments and predictions from recent modeling efforts.

  11. Surface plasmons: a strong alliance of electrons and light

    NASA Astrophysics Data System (ADS)

    Kroó, Norbert; Varró, Sándor; Rácz, Péter; Dombi, Péter

    2016-05-01

    Surface plasmon polaritons (SPPs) have several unique properties, including their strong-field enhancing effect in near field. This means, among other things, that nonlinear phenomena may be studied at much lower laser intensities. The present paper describes in detail the theory of basic properties of SPPs, and our model of a laser-induced oscillating double-layer potential. The SPPs may decay into photons and hot electrons. The latter may be emitted by a multi-plasmon process. Experiments on both photon and electron emission from a gold film are briefly presented.

  12. Strongly anisotropic wetting on one-dimensional nanopatterned surfaces.

    PubMed

    Xia, Deying; Brueck, S R J

    2008-09-01

    This communication reports strongly anisotropic wetting behavior on one-dimensional nanopatterned surfaces. Contact angles, degree of anisotropy, and droplet distortion are measured on micro- and nanopatterned surfaces fabricated with interference lithography. Both the degree of anisotropy and the droplet distortion are extremely high as compared with previous reports because of the well-defined nanostructural morphology. The surface is manipulated to tune with the wetting from hydrophobic to hydrophilic while retaining the structural wetting anisotropy with a simple silica nanoparticle overcoat. The wetting mechanisms are discussed. Potential applications in microfluidic devices and evaporation-induced pattern formation are demonstrated.

  13. The Italian Strong Motion Network (RAN)

    NASA Astrophysics Data System (ADS)

    Costa, Giovanni; Ammirati, Alfredo; de Nardis, Rita; Filippi, Luisa; Gallo, Antonella; Lavecchia, Giusy; Sirignano, Sebastiano; Zambonelli, Elisa; Nicoletti, Mario

    2014-05-01

    A network for the strong motion monitoring of the territory allows recording data that provide an excellent opportunity to study the source, path, and site effects on the ground motions, specifically in near source area, for updating seismic hazard map and consequently construction codes and earthquake resistant design. Strong motion data also help to increase the effective preparation and response to seismic emergencies and the ability of a community to quickly recover from the damages of an earthquake contributes to lower the seismic risk usually measured in term of casualties and economic losses. The Italian network for monitoring the strong movement of the national territory (RAN) is the result of a fruitful cooperation over the last 16 years between the Italian government, the regions and local authorities and now counts more than 500 stations. Over the years, as a priority the DPC has focused mainly on the expansion of the network in terms of the number of measurement points and technological improvement of instrumentation as well as the data transmission system. A data acquisition centre was implemented in which the Antelope software collects, processes and archives, automatically, the data of the RAN and of the external strong motion networks that contribute to the database of the RAN. Recently the DPC has dedicated specific resources to improve the response of the network, in particular, in case of emergency. The efficiency of the network on a daily basis is not less than 95% and temporary networks were installed in the epicentral area within 24 hours after the earthquake and connected to the data acquisition centre in Rome. A fast seismic data analysis is essential to provide useful information to Authorities which make decisions immediately after a strong earthquake occurrence. During a strong earthquake, the modern accelerometers are the only instruments which can provide near source high-quality data that are important both for scientific and for civil

  14. Strong Motion Recording in the United States

    NASA Astrophysics Data System (ADS)

    Archuleta, R. J.; Fletcher, J. B.; Shakal, A. F.

    2014-12-01

    The United States strong motion program began in 1932 when the Coast and Geodetic Survey (C&GS) installed eight strong motion accelerographs in California. During the March 1933 Long Beach earthquake, three of these produced the first strong motion records. With this success the C&GS expanded the number of accelerographs to 71 by 1964. With development of less expensive, mass-produced accelerographs the number of strong motion accelerographs expanded to ~575 by 1972. Responsibilities for operating the network and disseminating data were transferred to the National Oceanic and Atmospheric Administration in 1970 and then to the U.S. Geological Survey in 1973. In 1972 the California Legislature established the California Strong Motion Instrumentation Program (CSMIP). CSMIP operates accelerographs at 812 ground stations, with multi-channel accelerographs in 228 buildings, 125 lifelines and 37 geotechnical arrays, in California. The USGS and the ANSS effort operate accelerographs at 1584 ground stations, 96 buildings, 14 bridges, 70 dams, and 15 multi-channel geotechnical arrays. The USC Los Angeles array has 78 ground stations; UCSB operates 5 geotechnical arrays; other government and private institutions also operate accelerographs. Almost all accelerographs are now digital with a sampling rate of 200 Hz. Most of the strong motion data can be downloaded from the Center for Engineering Strong Motion Data (http://strongmotioncenter.org). As accelerographs have become more sophisticated, the concept of what constitutes strong motion has blurred because small earthquakes (M ~3) are well recorded on accelerometers as well as seismometers. However, when accelerations are over ~10%g and velocities over ~1 cm/s, the accelerometers remain on scale, providing the unclipped data necessary to analyze the ground motion and its consequences. Strong motion data are essential to the development of ground motion prediction equations, understanding structural response, performance

  15. Visible periodicity of strong nucleosome DNA sequences.

    PubMed

    Salih, Bilal; Tripathi, Vijay; Trifonov, Edward N

    2015-01-01

    Fifteen years ago, Lowary and Widom assembled nucleosomes on synthetic random sequence DNA molecules, selected the strongest nucleosomes and discovered that the TA dinucleotides in these strong nucleosome sequences often appear at 10-11 bases from one another or at distances which are multiples of this period. We repeated this experiment computationally, on large ensembles of natural genomic sequences, by selecting the strongest nucleosomes--i.e. those with such distances between like-named dinucleotides, multiples of 10.4 bases, the structural and sequence period of nucleosome DNA. The analysis confirmed the periodicity of TA dinucleotides in the strong nucleosomes, and revealed as well other periodic sequence elements, notably classical AA and TT dinucleotides. The matrices of DNA bendability and their simple linear forms--nucleosome positioning motifs--are calculated from the strong nucleosome DNA sequences. The motifs are in full accord with nucleosome positioning sequences derived earlier, thus confirming that the new technique, indeed, detects strong nucleosomes. Species- and isochore-specific variations of the matrices and of the positioning motifs are demonstrated. The strong nucleosome DNA sequences manifest the highest hitherto nucleosome positioning sequence signals, showing the dinucleotide periodicities in directly observable rather than in hidden form.

  16. Global gyrokinetic simulations with strong flows

    NASA Astrophysics Data System (ADS)

    Collier, J. D.; McMillan, B. F.; Robinson, J. R.

    2016-11-01

    We report on the investigation of strong toroidal rotation effects in a global tokamak code, ORB5. This includes the implementation of a strong flow gyrokinetic Lagrangian, allowing a complete treatment of centrifugal and Coriolis effects in the laboratory frame. In order to consistently perform the linear analysis in this system, an axisymmetric gyrokinetic equilibrium distribution function is defined using the constants of motion: we show it corresponds to the standard choice in the local limit and is close to the neoclassical solution in the banana regime. The energy and momentum transport equations are presented in an analogous form to those for the weak flow system. Linear studies of Ion Temperature Gradient (ITG) modes in rotating plasmas are performed to determine how the global effects interact with the effects of strong rotation. We also determine the geodesic acoustic mode dispersion with respect to plasma rotation rate in this gyrokinetic model and compare it to MHD theory.

  17. Multiscale equations for strongly stratified turbulent flows

    NASA Astrophysics Data System (ADS)

    Chini, Greg; Rocha, Cesar; Julien, Keith; Caulfield, Colm-Cille

    2016-11-01

    Strongly stratified turbulent shear flows are of fundamental importance owing to their widespread occurrence and their impact on diabatic mixing, yet direct numerical simulations of such flows remain challenging. Here, a reduced, multiscale description of turbulent shear flows in the presence of strong stable density stratification is derived via asymptotic analysis of the governing Boussinesq equations. The analysis explicitly recognizes the occurrence of dynamics on disparate spatiotemoporal scales, and yields simplified partial differential equations governing the coupled evolution of slowly-evolving small aspect-ratio ('pancake') modes and isotropic, strongly non-hydrostatic stratified-shear (e.g. Kelvin-Helmholtz) instability modes. The reduced model is formally valid in the physically-relevant regime in which the aspect-ratio of the pancake structures tends to zero in direct proportion to the horizontal Froude number. Relative to the full Boussinesq equations, the model offers both computational and conceptual advantages.

  18. Strong field laser control of photochemistry.

    PubMed

    Solá, Ignacio R; González-Vázquez, Jesús; de Nalda, Rebeca; Bañares, Luis

    2015-05-28

    Strong ultrashort laser pulses have opened new avenues for the manipulation of photochemical processes like photoisomerization or photodissociation. The presence of light intense enough to reshape the potential energy surfaces may steer the dynamics of both electrons and nuclei in new directions. A controlled laser pulse, precisely defined in terms of spectrum, time and intensity, is the essential tool in this type of approach to control chemical dynamics at a microscopic level. In this Perspective we examine the current strategies developed to achieve control of chemical processes with strong laser fields, as well as recent experimental advances that demonstrate that properties like the molecular absorption spectrum, the state lifetimes, the quantum yields and the velocity distributions in photodissociation processes can be controlled by the introduction of carefully designed strong laser fields.

  19. Strongly nonlinear stress waves in dissipative metamaterials

    NASA Astrophysics Data System (ADS)

    Xu, Yichao; Nesterenko, Vitali F.

    2017-01-01

    We present the results of measurements and numerical simulations of stress wave propagation in a one-dimensional strongly nonlinear dissipative metamaterial composed of steel disks and Nitrile O-rings. The incoming bell shape stress wave is generated by the strikers with different masses. Numerical modeling including a viscous dissipative term to describe dynamic behavior of O-rings is developed to predict the wave amplitude, shape and propagation speed of stress waves. The viscous dissipation prevented the incoming pulse from splitting into trains of solitary waves typical for non-dissipative strongly nonlinear discrete systems. The linear momentum and energy from the striker were completely transferred into this strongly nonlinear "soft" metamaterial.

  20. Nanostructure studies of strongly correlated materials.

    PubMed

    Wei, Jiang; Natelson, Douglas

    2011-09-01

    Strongly correlated materials exhibit an amazing variety of phenomena, including metal-insulator transitions, colossal magnetoresistance, and high temperature superconductivity, as strong electron-electron and electron-phonon couplings lead to competing correlated ground states. Recently, researchers have begun to apply nanostructure-based techniques to this class of materials, examining electronic transport properties on previously inaccessible length scales, and applying perturbations to drive systems out of equilibrium. We review progress in this area, particularly emphasizing work in transition metal oxides (Fe(3)O(4), VO(2)), manganites, and high temperature cuprate superconductors. We conclude that such nanostructure-based studies have strong potential to reveal new information about the rich physics at work in these materials.

  1. Markovian evolution of strongly coupled harmonic oscillators

    NASA Astrophysics Data System (ADS)

    Joshi, Chaitanya; Öhberg, Patrik; Cresser, James D.; Andersson, Erika

    2014-12-01

    We investigate how to model Markovian evolution of coupled harmonic oscillators, each of them interacting with a local environment. When the coupling between the oscillators is weak, dissipation may be modeled using local Lindblad terms for each of the oscillators in the master equation, as is commonly done. When the coupling between oscillators is strong, this model may become invalid. We derive a master equation for two coupled harmonic oscillators that are subject to individual heat baths modeled by a collection of harmonic oscillators and show that this master equation in general contains nonlocal Lindblad terms. We compare the resulting time evolution with that obtained for dissipation through local Lindblad terms for each individual oscillator and show that the evolution is different in the two cases. In particular, the two descriptions give different predictions for the steady state and for the entanglement between strongly coupled oscillators. This shows that when describing strongly coupled harmonic oscillators, one must take great care in how dissipation is modeled and that a description using local Lindblad terms may fail. This may be particularly relevant when attempting to generate entangled states of strongly coupled quantum systems.

  2. MRS photodiode in strong magnetic field

    SciTech Connect

    Beznosko, D.; Blazey, G.; Dyshkant, A.; Francis, K.; Kubik, D.; Rykalin, V.; Tartaglia, M.A.; Zutshi, v.; /Northern Illinois U.

    2004-12-01

    The experimental results on the performance of the MRS (Metal/Resistor/Semiconductor) photodiode in the strong magnetic field of 4.4T, and the possible impact of the quench of the magnet at 4.5T on sensor's operation are reported.

  3. Semimetallization of dielectrics in strong optical fields

    DOE PAGES

    Kwon, Ojoon; Paasch-Colberg, Tim; Apalkov, Vadym; ...

    2016-02-18

    At the heart of ever growing demands for faster signal processing is ultrafast charge transport and control by electromagnetic fields in semiconductors. Intense optical fields have opened fascinating avenues for new phenomena and applications in solids. Because the period of optical fields is on the order of a femtosecond, the current switching and its control by an optical field may pave a way to petahertz optoelectronic devices. Lately, a reversible semimetallization in fused silica on a femtosecond time scale by using a few-cycle strong field (~1 V/Å) is manifested. The strong Wannier-Stark localization and Zener-type tunneling were expected to drivemore » this ultrafast semimetallization. Wider spread of this technology demands better understanding of whether the strong field behavior is universally similar for different dielectrics. Here we employ a carrier-envelope-phase stabilized, few-cycle strong optical field to drive the semimetallization in sapphire, calcium fluoride and quartz and to compare this phenomenon and show its remarkable similarity between them. The similarity in response of these materials, despite the distinguishable differences in their physical properties, suggests the universality of the physical picture explained by the localization of Wannier-Stark states. Lastly, our results may blaze a trail to PHz-rate optoelectronics.« less

  4. Strong Female Characters in Recent Children's Literature.

    ERIC Educational Resources Information Center

    Heine, Pat; Inkster, Christine; Kazemek, Frank; Williams, Sandra; Raschke, Sylvia; Stevens, Della

    1999-01-01

    Shares the authors' criteria for evaluating female characters as positive role models in children's literature. Explores the criteria by examining "The Ballad of Lucy Wipple" (Karen Cushman). Discusses other recently published picture books and novels which feature strong females in history, in contemporary times, and in fantasy. (SR)

  5. Patterns of strong coupling for LHC searches

    NASA Astrophysics Data System (ADS)

    Liu, Da; Pomarol, Alex; Rattazzi, Riccardo; Riva, Francesco

    2016-11-01

    Even though the Standard Model (SM) is weakly coupled at the Fermi scale, a new strong dynamics involving its degrees of freedom may conceivably lurk at slightly higher energies, in the multi TeV range. Approximate symmetries provide a structurally robust context where, within the low energy description, the dimensionless SM couplings are weak, while the new strong dynamics manifests itself exclusively through higher-derivative interactions. We present an exhaustive classification of such scenarios in the form of effective field theories, paying special attention to new classes of models where the strong dynamics involves, along with the Higgs boson, the SM gauge bosons and/or the fermions. The IR softness of the new dynamics suppresses its effects at LEP energies, but deviations are in principle detectable at the LHC, even at energies below the threshold for production of new states. We believe our construction provides the so far unique structurally robust context where to motivate several LHC searches in Higgs physics, diboson production, or W W scattering. Perhaps surprisingly, the interplay between weak coupling, strong coupling and derivatives, which is controlled by symmetries, can override the naive expansion in operator dimension, providing instances where dimension-8 dominates dimension-6, well within the domain of validity of the low energy effective theory. This result reveals the limitations of an analysis that is both ambitiously general and restricted to dimension-6 operators.

  6. Strong motion duration and earthquake magnitude relationships

    SciTech Connect

    Salmon, M.W.; Short, S.A.; Kennedy, R.P.

    1992-06-01

    Earthquake duration is the total time of ground shaking from the arrival of seismic waves until the return to ambient conditions. Much of this time is at relatively low shaking levels which have little effect on seismic structural response and on earthquake damage potential. As a result, a parameter termed ``strong motion duration`` has been defined by a number of investigators to be used for the purpose of evaluating seismic response and assessing the potential for structural damage due to earthquakes. This report presents methods for determining strong motion duration and a time history envelope function appropriate for various evaluation purposes, for earthquake magnitude and distance, and for site soil properties. There are numerous definitions of strong motion duration. For most of these definitions, empirical studies have been completed which relate duration to earthquake magnitude and distance and to site soil properties. Each of these definitions recognizes that only the portion of an earthquake record which has sufficiently high acceleration amplitude, energy content, or some other parameters significantly affects seismic response. Studies have been performed which indicate that the portion of an earthquake record in which the power (average rate of energy input) is maximum correlates most closely with potential damage to stiff nuclear power plant structures. Hence, this report will concentrate on energy based strong motion duration definitions.

  7. Semimetallization of dielectrics in strong optical fields

    SciTech Connect

    Kwon, Ojoon; Apalkov, Vadym; Kim, Bum -Kyu; Kim, Ju -Jin; Stockman, Mark I.; Kim, D.

    2016-02-18

    At the heart of ever growing demands for faster signal processing is ultrafast charge transport and control by electromagnetic fields in semiconductors. Intense optical fields have opened fascinating avenues for new phenomena and applications in solids. Because the period of optical fields is on the order of a femtosecond, the current switching and its control by an optical field may pave a way to petahertz optoelectronic devices. Lately, a reversible semimetallization in fused silica on a femtosecond time scale by using a few-cycle strong field (~1 V/Å) is manifested. The strong Wannier-Stark localization and Zener-type tunneling were expected to drive this ultrafast semimetallization. Wider spread of this technology demands better understanding of whether the strong field behavior is universally similar for different dielectrics. Here we employ a carrier-envelope-phase stabilized, few-cycle strong optical field to drive the semimetallization in sapphire, calcium fluoride and quartz and to compare this phenomenon and show its remarkable similarity between them. The similarity in response of these materials, despite the distinguishable differences in their physical properties, suggests the universality of the physical picture explained by the localization of Wannier-Stark states. Lastly, our results may blaze a trail to PHz-rate optoelectronics.

  8. Strongly correlated photons on a chip

    NASA Astrophysics Data System (ADS)

    Reinhard, Andreas; Volz, Thomas; Winger, Martin; Badolato, Antonio; Hennessy, Kevin J.; Hu, Evelyn L.; Imamoğlu, Ataç

    2012-02-01

    Optical nonlinearities at the single-photon level are key ingredients for future photonic quantum technologies. Prime candidates for the realization of the strong photon-photon interactions necessary for implementing quantum information processing tasks, as well as for studying strongly correlated photons in an integrated photonic device setting, are quantum dots embedded in photonic-crystal nanocavities. Here, we report strong quantum correlations between photons on picosecond timescales. We observe (i) photon antibunching upon resonant excitation of the lowest-energy polariton state, proving that the first cavity photon blocks the subsequent injection events, and (ii) photon bunching when the laser field is in two-photon resonance with the polariton eigenstates of the second Jaynes-Cummings manifold, demonstrating that two photons at this colour are more likely to be injected into the cavity jointly than they would otherwise. Together, these results demonstrate unprecedented strong single-photon nonlinearities, paving the way for the realization of a quantum optical Josephson interferometer or a single-photon transistor.

  9. Semimetallization of dielectrics in strong optical fields

    NASA Astrophysics Data System (ADS)

    Kwon, Ojoon; Paasch-Colberg, Tim; Apalkov, Vadym; Kim, Bum-Kyu; Kim, Ju-Jin; Stockman, Mark I.; Kim, D.

    2016-02-01

    At the heart of ever growing demands for faster signal processing is ultrafast charge transport and control by electromagnetic fields in semiconductors. Intense optical fields have opened fascinating avenues for new phenomena and applications in solids. Because the period of optical fields is on the order of a femtosecond, the current switching and its control by an optical field may pave a way to petahertz optoelectronic devices. Lately, a reversible semimetallization in fused silica on a femtosecond time scale by using a few-cycle strong field (~1 V/Å) is manifested. The strong Wannier-Stark localization and Zener-type tunneling were expected to drive this ultrafast semimetallization. Wider spread of this technology demands better understanding of whether the strong field behavior is universally similar for different dielectrics. Here we employ a carrier-envelope-phase stabilized, few-cycle strong optical field to drive the semimetallization in sapphire, calcium fluoride and quartz and to compare this phenomenon and show its remarkable similarity between them. The similarity in response of these materials, despite the distinguishable differences in their physical properties, suggests the universality of the physical picture explained by the localization of Wannier-Stark states. Our results may blaze a trail to PHz-rate optoelectronics.

  10. Semimetallization of dielectrics in strong optical fields

    PubMed Central

    Kwon, Ojoon; Paasch-Colberg, Tim; Apalkov, Vadym; Kim, Bum-Kyu; Kim, Ju-Jin; Stockman, Mark I.; Kim, D.

    2016-01-01

    At the heart of ever growing demands for faster signal processing is ultrafast charge transport and control by electromagnetic fields in semiconductors. Intense optical fields have opened fascinating avenues for new phenomena and applications in solids. Because the period of optical fields is on the order of a femtosecond, the current switching and its control by an optical field may pave a way to petahertz optoelectronic devices. Lately, a reversible semimetallization in fused silica on a femtosecond time scale by using a few-cycle strong field (~1 V/Å) is manifested. The strong Wannier-Stark localization and Zener-type tunneling were expected to drive this ultrafast semimetallization. Wider spread of this technology demands better understanding of whether the strong field behavior is universally similar for different dielectrics. Here we employ a carrier-envelope-phase stabilized, few-cycle strong optical field to drive the semimetallization in sapphire, calcium fluoride and quartz and to compare this phenomenon and show its remarkable similarity between them. The similarity in response of these materials, despite the distinguishable differences in their physical properties, suggests the universality of the physical picture explained by the localization of Wannier-Stark states. Our results may blaze a trail to PHz-rate optoelectronics. PMID:26888147

  11. CSMIP (California Strong Motion Instrumentation Program) strong-motion records from the Santa Cruz Mountains (Loma Prieta), California earthquake of 17 October 1989

    SciTech Connect

    Shakal, A.; Reichle, M.; Ventura, C.; Cao, T.; Sherburne, R.; Savage, M.; Darragh, R.; Petersen, C.

    1990-01-01

    Strong-motion records were recovered from 93 stations of the California Strong Motion Instrumentation Program (CSMIP) after the earthquake. CSMIP provides information on the force of ground motion and the deformation induced in structures and in rock and soil by earthquake-generated ground motion. This information is recorded by strong-motion sensors placed in engineered structures and at free field (ground) sites, and is used by earthquake engineers and earth scientists to improve the design of earthquake-resistant structures. The strong-motion instrumentation program was established after the San Fernando earthquake in 1971. A total of 125 records were recovered from the 93 CSMIP stations which recorded the Loma Prieta event. These 125 records contain data from a total of 690 strong-motion sensors. These data are important because of the unique structures and sites at which records were obtained during this event. Some highlights of particular interest are included in this paper.

  12. Using strong electromagnetic fields to control x-ray processes.

    SciTech Connect

    Young, L.; Buth, C.; Dunford, R. W.; Ho, P.; Kanter, E. P.; Kraessig, B.; Peterson, E. R.; Rohringer, N.; Santra, R.; Southworth, S. H.

    2010-06-01

    Exploration of a new ultrafast-ultrasmall frontier in atomic and molecular physics has begun. Not only is is possible to control outer-shell electron dynamics with intense ultrafast optical lasers, but now control of inner-shell processes has become possible by combining intense infrared/optical lasers with tunable sources of X-ray radiation. This marriage of strong-field laser and X-ray physics has led to the discovery of methods to control reversibly resonant X-ray absorption in atoms and molecules on ultrafast timescales. Using a strong optical dressing field, resonant X-ray absorption in atoms can be markedly suppressed, yielding an example of electromagnetically induced transparency for x rays. Resonant X-ray absorption can also be controlled in molecules using strong non-resonant, polarized laser fields to align the framework of a molecule, and therefore its unoccupied molecular orbitals to which resonant absorption occurs. At higher laser intensities, ultrafast field ionization produces an irreversible change in X-ray absorption. Finally, the advent of X-ray free electron lasers enables first exploration of non-linear X-ray processes.

  13. Strong-Field Control of Laser Filamentation Mechanisms

    NASA Astrophysics Data System (ADS)

    Levis, Robert; Romanov, Dmitri; Filin, Aleskey; Compton, Ryan

    2008-05-01

    The propagation of short strong-file laser pulses in gas and solution phases often result in formation of filaments. This phenomenon involves many nonlinear processes including Kerr lensing, group velocity dispersion, multi-photon ionization, plasma defocusing, intensity clamping, and self-steepening. Of these, formation and dynamics of pencil-shape plasma areas plays a crucial role. The fundamental understanding of these laser-induced plasmas requires additional effort, because the process is highly nonlinear and complex. We studied the ultrafast laser-generated plasma dynamics both experimentally and theoretically. Ultrafast plasma dynamics was probed using Coherent Anti-Stokes Raman Scattering. The measurements were made in a room temperature gas maintained at 1 atm in a flowing cell. The time dependent scattering was measured by delaying the CARS probe with respect to the intense laser excitation pulse. A general trend is observed between the spacing of the ground state and the first allowed excited state with the rise time for the noble gas series and the molecular gases. This trend is consistent with our theoretical model, which considers the ultrafast dynamics of the strong field generated plasma as a three-step process; (i) strong-field ionization followed by the electron gaining considerable kinetic energy during the pulse; (ii) immediate post-pulse dynamics: fast thermalization, impact-ionization-driven electron multiplication and cooling; (iii) ensuing relaxation: evolution to electron-ion equilibrium and eventual recombination.

  14. Strong bending of purple membranes in the M-state.

    PubMed

    Porschke, Dietmar

    2003-08-15

    Structure changes of purple membranes during the photocycle were analysed in solution by measurements of the electric dichroism. The D96N-mutant was used to characterize the M-state at neutral pH. The transition from the resting state to 61% photo-stationary M-state is associated with a strong reduction of the dichroism decay time constant by a factor of approximately 2. Because the change of the time constant is independent of the bacteriorhodopsin concentration, the effect is not attributed to light-induced dissociation but to light-induced bending of purple membranes. After termination of light-activation the dichroism decay of the resting state is restored with a time constant close to that of the M-state decay, which is more than two orders of magnitude slower than proton transfer to the bulk. Thus, bending is not due to asymmetric protonation but to the structure of the M-state. A very similar reduction of decay time constants at a corresponding degree of light-activation was found for wild-type bacteriorhodopsin at pH-values 7.8-9.3, where the lifetime of the M-state is extended. Light-induced bending is also reflected in changes of the stationary dichroism, whereas the overall permanent dipole moment remains almost constant, suggesting compensation of changes in molecular and global contributions. Bead model simulations indicate that disks of approximately 1 microm diameter are bent at a degree of photo-activation of 61% to a radius of approximately 0.25 microm, assuming a cylindrical bending modus. The large light-induced bending effect is consistent with light-induced opening of the protein on the cytoplasmic side of the membrane detected by electron crystallography, which is amplified due to coupling of monomers in the membrane. Bending may function as a mechanical signal.

  15. Solvable model of a strongly driven micromaser

    SciTech Connect

    Lougovski, P.; Walther, H.; Casagrande, F.; Lulli, A.; Englert, B.-G.; Solano, E.

    2004-02-01

    We study the dynamics of a micromaser where the pumping atoms are strongly driven by a resonant classical field during their transit through the cavity mode. We derive a master equation for this strongly driven micromaser, involving the contributions of the unitary atom-field interactions and the dissipative effects of a thermal bath. We find analytical solutions for the temporal evolution and the steady state of this system by means of phase-space techniques, providing an unusual solvable model of an open quantum system, including pumping and decoherence. We derive closed expressions for all relevant expectation values, describing the statistics of the cavity field and the detected atomic levels. The transient regime shows the buildup of mixtures of mesoscopic fields evolving towards a super-Poissonian steady-state field that, nevertheless, yields atomic correlations that exhibit stronger nonclassical features than the conventional micromaser.

  16. New strong interactions above the electroweak scale

    SciTech Connect

    White, A.R.

    1994-08-09

    Theoretical arguments for a new higher-color quark sector, based on Pomeron physics in QCD, are briefly described. The electroweak symmetry-breaking, Strong CP conservation, and electroweak scale CP violation, that is naturally produced by this sector is also outlined. A further consequence is that above the electroweak scale there will be a radical change in the strong interaction. Electroweak states, in particular multiple W`s and Z`s, and new, semi-stable, very massive, baryons, will be commonly produced. The possible correlation of expected phenomena with a wide range of observed Cosmic Ray effects at and above the primary spectrum knee is described. Related phenomena that might be seen in the highest energy hard scattering events at the Fermilab Tevatron, some of which could be confused with top production, are also briefly discussed.

  17. Cosmogenic photons strongly constrain UHECR source models

    NASA Astrophysics Data System (ADS)

    van Vliet, Arjen

    2017-03-01

    With the newest version of our Monte Carlo code for ultra-high-energy cosmic ray (UHECR) propagation, CRPropa 3, the flux of neutrinos and photons due to interactions of UHECRs with extragalactic background light can be predicted. Together with the recently updated data for the isotropic diffuse gamma-ray background (IGRB) by Fermi LAT, it is now possible to severely constrain UHECR source models. The evolution of the UHECR sources especially plays an important role in the determination of the expected secondary photon spectrum. Pure proton UHECR models are already strongly constrained, primarily by the highest energy bins of Fermi LAT's IGRB, as long as their number density is not strongly peaked at recent times.

  18. Firefly flashing under strong static magnetic field.

    PubMed

    Barua, Anurup Gohain; Iwasaka, Masakazu; Miyashita, Yuito; Kurita, Satoru; Owada, Norio

    2012-02-01

    Firefly flashing has been the subject of numerous scientific investigations. Here we present in vivo flashes from male specimens of three species of fireflies-two Japanese species Luciola cruciata, Luciola lateralis and one Indian species Luciola praeusta-positioned under a superconducting magnet. When the OFF state of the firefly becomes long after flashing in an immobile state under the strong static magnetic field of strength 10 Tesla for a long time, which varies widely from species to species as well as from specimen to specimen, the effect of the field becomes noticeable. The flashes in general are more rapid, and occasionally overlap to produce broad compound flashes. We present the broadest flashes recorded to date, and propose that the strong static magnetic field affects the neural activities of fireflies, especially those in the spent up or 'exhausted' condition.

  19. Strong sum distance in fuzzy graphs.

    PubMed

    Tom, Mini; Sunitha, Muraleedharan Shetty

    2015-01-01

    In this paper the idea of strong sum distance which is a metric, in a fuzzy graph is introduced. Based on this metric the concepts of eccentricity, radius, diameter, center and self centered fuzzy graphs are studied. Some properties of eccentric nodes, peripheral nodes and central nodes are obtained. A characterisation of self centered complete fuzzy graph is obtained and conditions under which a fuzzy cycle is self centered are established. We have proved that based on this metric, an eccentric node of a fuzzy tree G is a fuzzy end node of G and a node is an eccentric node of a fuzzy tree if and only if it is a peripheral node of G and the center of a fuzzy tree consists of either one or two neighboring nodes. The concepts of boundary nodes and interior nodes in a fuzzy graph based on strong sum distance are introduced. Some properties of boundary nodes, interior nodes and complete nodes are studied.

  20. Molecular systems in a strong magnetic field

    NASA Astrophysics Data System (ADS)

    Turbiner, Alexander V.

    2007-04-01

    Brief overview of one-two electron molecular systems made out of protons and/or α-particles in a strong magnetic field B≤4.414×1013 G is presented. A particular emphasis is given to the one-electron exotic ions H 3 ++ (pppe), He 2 3+ (α α e) and to two-electron ionsH 3 + (pppee), He 2 ++ (α α ee). Quantitative studies in a strong magnetic field are very complicated technically. Novel approach to the few-electron Coulomb systems in magnetic field, which provides accurate results, based on variational calculus with physically relevant trial functions is briefly described.

  1. Strong gravitational lensing and dark energy complementarity

    SciTech Connect

    Linder, Eric V.

    2004-01-21

    In the search for the nature of dark energy most cosmological probes measure simple functions of the expansion rate. While powerful, these all involve roughly the same dependence on the dark energy equation of state parameters, with anticorrelation between its present value w{sub 0} and time variation w{sub a}. Quantities that have instead positive correlation and so a sensitivity direction largely orthogonal to, e.g., distance probes offer the hope of achieving tight constraints through complementarity. Such quantities are found in strong gravitational lensing observations of image separations and time delays. While degeneracy between cosmological parameters prevents full complementarity, strong lensing measurements to 1 percent accuracy can improve equation of state characterization by 15-50 percent. Next generation surveys should provide data on roughly 105 lens systems, though systematic errors will remain challenging.

  2. Decay of Resonaces in Strong Magnetic Field

    NASA Astrophysics Data System (ADS)

    Filip, Peter

    2015-08-01

    We suggest that decay properties (branching ratios) of hadronic resonances may become modified in strong external magnetic field. The behavior of K±*, K0* vector mesons as well as Λ* (1520) and Ξ0* baryonic states is considered in static fields 1013-1015 T. In particular, n = 0 Landau level energy increase of charged particles in the external magnetic field, and the interaction of hadron magnetic moments with the field is taken into account. We suggest that enhanced yield of dileptons and photons from ρ0(770) mesons may occur if strong decay channel ρ0 → π+π- is significantly suppressed. CP - violating π+π- decays of pseudoscalar ηc and η(547) mesons in the magnetic field are discussed, and superpositions of quarkonium states ηc,b and χc,b(nP) with Ψ(nS), ϒ(nS) mesons in the external field are considered.

  3. Strong ground motion prediction using virtual earthquakes.

    PubMed

    Denolle, M A; Dunham, E M; Prieto, G A; Beroza, G C

    2014-01-24

    Sedimentary basins increase the damaging effects of earthquakes by trapping and amplifying seismic waves. Simulations of seismic wave propagation in sedimentary basins capture this effect; however, there exists no method to validate these results for earthquakes that have not yet occurred. We present a new approach for ground motion prediction that uses the ambient seismic field. We apply our method to a suite of magnitude 7 scenario earthquakes on the southern San Andreas fault and compare our ground motion predictions with simulations. Both methods find strong amplification and coupling of source and structure effects, but they predict substantially different shaking patterns across the Los Angeles Basin. The virtual earthquake approach provides a new approach for predicting long-period strong ground motion.

  4. Photoneutrino energy losses in strong magnetic fields.

    NASA Technical Reports Server (NTRS)

    Canuto, V.; Fassio-Canuto, L.

    1973-01-01

    Previously computed rates of energy losses (Petrosian et al., 1967) ignored the presence of strong magnetic fields, hence the change brought in when such a field (about 10 to the 12th to 10 to the 13th power G) is included is studied. The results indicate that for T about 10 to the 8th power K and densities rho of about 10,000 g/cu cm, the presence of a strong H field decreases the energy losses by at the most a factor between 10 and 100 in the region up to rho = 1,000,000 g/cu cm. At higher densities the neutrino emissivities are almost identical.

  5. Quantum strongly secure ramp secret sharing

    NASA Astrophysics Data System (ADS)

    Zhang, Paul; Matsumoto, Ryutaroh

    2015-02-01

    Quantum secret sharing is a scheme for encoding a quantum state (the secret) into multiple shares and distributing them among several participants. If a sufficient number of shares are put together, then the secret can be fully reconstructed. If an insufficient number of shares are put together however, no information about the secret can be revealed. In quantum ramp secret sharing, partial information about the secret is allowed to leak to a set of participants, called an unqualified set, that cannot fully reconstruct the secret. By allowing this, the size of a share can be drastically reduced. This paper introduces a quantum analog of classical strong security in ramp secret sharing schemes. While the ramp secret sharing scheme still leaks partial information about the secret to unqualified sets of participants, the strong security condition ensures that qudits with critical information can no longer be leaked.

  6. NON-PARAMETRIC ESTIMATION UNDER STRONG DEPENDENCE

    PubMed Central

    Zhao, Zhibiao; Zhang, Yiyun; Li, Runze

    2014-01-01

    We study non-parametric regression function estimation for models with strong dependence. Compared with short-range dependent models, long-range dependent models often result in slower convergence rates. We propose a simple differencing-sequence based non-parametric estimator that achieves the same convergence rate as if the data were independent. Simulation studies show that the proposed method has good finite sample performance. PMID:25018572

  7. Strong transverse fields in delta-spots

    NASA Technical Reports Server (NTRS)

    Zirin, Harold; Wang, Haimin

    1993-01-01

    Spectroscopic measurements of the strength and direction of transverse magnetic fields in six delta-spots are presented. The field direction is determined by the relative strength of the pi- and sigma-components at different polarizer orientations, and is, with one exception, parallel to the neutral line and as strong as the umbral field. Field strengths determined by line splitting are as high as 3980 G.

  8. Kinetic Characterization of Strongly Coupled Systems

    SciTech Connect

    Knapek, C. A.; Ivlev, A. V.; Klumov, B. A.; Morfill, G. E.; Samsonov, D.

    2007-01-05

    We propose a simple method to determine the local coupling strength {gamma} experimentally, by linking the individual particle dynamics with the local density and crystal structure of a 2D plasma crystal. By measuring particle trajectories with high spatial and temporal resolution we obtain the first maps of {gamma} and temperature at individual particle resolution. We employ numerical simulations to test this new method, and discuss the implications to characterize strongly coupled systems.

  9. Quantum states with strong positive partial transpose

    SciTech Connect

    Chruscinski, Dariusz; Jurkowski, Jacek; Kossakowski, Andrzej

    2008-02-15

    We construct a large class of bipartite M x N quantum states which defines a proper subset of states with positive partial transposes (PPTs). Any state from this class has PPT but the positivity of its partial transposition is recognized with respect to canonical factorization of the original density operator. We propose to call elements from this class states with strong positive partial transposes (SPPTs). We conjecture that all SPPT states are separable.

  10. Strong coupling QED with two fermionic flavors

    SciTech Connect

    Wang, K.C.

    1990-11-01

    We report the recent results of our simulation of strong coupling QED, with non-compact action, on lattices 10{sup 4} and 16{sup 4}. Since we are dealing with two staggered fermionic flavors, we use hybrid algorithm to do the simulation. In addition to the measurement of the chiral order parameter {l angle}{bar {psi}}{psi}{r angle}, we also measure magnetic monopole susceptibility, {chi}, throughout the region of chiral transition. 6 refs., 6 figs.

  11. Bose polarons in the strongly interacting regime

    NASA Astrophysics Data System (ADS)

    Kedar, Dhruv; Hu, Ming-Guang; van de Graaff, Michael; Corson, John; Cornell, Eric; Jin, Deborah

    2016-05-01

    Impurities immersed in and interacting with a Bose-Einstein condensate (BEC) are predicted to form quasiparticle excitations called Bose polarons. I will present experimental evidence of Bose polarons in cold atoms obtained using radio-frequency spectroscopy to measure the excitation spectrum of fermionic K-40 impurities interacting with a BEC of Rb-87 atoms. We use an interspecies Feshbach resonance to tune the interactions between the impurities and the bosons, and we take data in the strongly interacting regime.

  12. NON-PARAMETRIC ESTIMATION UNDER STRONG DEPENDENCE.

    PubMed

    Zhao, Zhibiao; Zhang, Yiyun; Li, Runze

    2014-01-01

    We study non-parametric regression function estimation for models with strong dependence. Compared with short-range dependent models, long-range dependent models often result in slower convergence rates. We propose a simple differencing-sequence based non-parametric estimator that achieves the same convergence rate as if the data were independent. Simulation studies show that the proposed method has good finite sample performance.

  13. Concepts in strong Langmuir turbulence theory

    SciTech Connect

    DuBois, D.F.; Rose, H.A.

    1990-01-01

    Some of the basic concepts of strong Langmuir turbulence (SLT) theory are reviewed. In SLT system, a major fraction of the turbulent energy is carried by local, time-dependent, nonlinear excitations called cavitons. Modulational instability, localization of Langmuir fields by density fluctuations, caviton nucleation, collapse, and burnout and caviton correlations are reviewed. Recent experimental evidence will be presented for SLT phenomena in the interaction of powerful HF waves with the ionosphere and in laser-plasma interaction experiments. 38 refs., 11 figs.

  14. Inflationary magnetogenesis without the strong coupling problem

    SciTech Connect

    Ferreira, Ricardo J.Z.; Jain, Rajeev Kumar; Sloth, Martin S. E-mail: jain@cp3.dias.sdu.dk

    2013-10-01

    The simplest gauge invariant models of inflationary magnetogenesis are known to suffer from the problems of either large backreaction or strong coupling, which make it difficult to self-consistently achieve cosmic magnetic fields from inflation with a field strength larger than 10{sup −32}G today on the Mpc scale. Such a strength is insufficient to act as seed for the galactic dynamo effect, which requires a magnetic field larger than 10{sup −20}G. In this paper we analyze simple extensions of the minimal model, which avoid both the strong coupling and back reaction problems, in order to generate sufficiently large magnetic fields on the Mpc scale today. First we study the possibility that the coupling function which breaks the conformal invariance of electromagnetism is non-monotonic with sharp features. Subsequently, we consider the effect of lowering the energy scale of inflation jointly with a scenario of prolonged reheating where the universe is dominated by a stiff fluid for a short period after inflation. In the latter case, a systematic study shows upper bounds for the magnetic field strength today on the Mpc scale of 10{sup −13}G for low scale inflation and 10{sup −25}G for high scale inflation, thus improving on the previous result by 7-19 orders of magnitude. These results are consistent with the strong coupling and backreaction constraints.

  15. Cosmological test using strong gravitational lensing systems

    NASA Astrophysics Data System (ADS)

    Yuan, C. C.; Wang, F. Y.

    2015-09-01

    As one of the probes of universe, strong gravitational lensing systems allow us to compare different cosmological models and constrain vital cosmological parameters. This purpose can be reached from the dynamic and geometry properties of strong gravitational lensing systems, for instance, time-delay Δτ of images, the velocity dispersion σ of the lensing galaxies and the combination of these two effects, Δτ/σ2. In this paper, in order to carry out one-on-one comparisons between ΛCDM universe and Rh = ct universe, we use a sample containing 36 strong lensing systems with the measurement of velocity dispersion from the Sloan Lens Advanced Camera for Surveys (SLACS) and Lens Structure and Dynamic survey (LSD) survey. Concerning the time-delay effect, 12 two-image lensing systems with Δτ are also used. In addition, Monte Carlo simulations are used to compare the efficiency of the three methods as mentioned above. From simulations, we estimate the number of lenses required to rule out one model at the 99.7 per cent confidence level. Comparing with constraints from Δτ and the velocity dispersion σ, we find that using Δτ/σ2 can improve the discrimination between cosmological models. Despite the independence tests of these methods reveal a correlation between Δτ/σ2 and σ, Δτ/σ2 could be considered as an improved method of σ if more data samples are available.

  16. Diphotons, new vacuum angles, and strong CP

    DOE PAGES

    Draper, Patrick; McKeen, David

    2016-04-20

    The Standard Model contains a well-understood, natural, spin-0 diphoton resonance: the π0. Numerous studies have pointed out that the hint of a new diphoton resonance at 750 GeV could be a pion analog, identified with the pseudo-Nambu-Goldstone boson of a chiral symmetry spontaneously broken by new strong dynamics at the TeV scale. These “hypercolor” models are generically expected to violate parity through a topological angle θ~. We discuss the physics of θ~ and its impact on the phenomenology of the new sector. We also describe some of the theoretical implications of a nonzero θ~. In particular, θ~ can generate anmore » O(1) threshold correction to the QCD vacuum angle θ near the TeV scale, sharply constraining ultraviolet solutions to the strong CP problem. Furthermore, finding that θ~ is small may be interpreted as evidence in favor of UV solutions to strong CP, particularly those based on spontaneously broken P or CP symmetries.« less

  17. Diphotons, new vacuum angles, and strong CP

    SciTech Connect

    Draper, Patrick; McKeen, David

    2016-04-20

    The Standard Model contains a well-understood, natural, spin-0 diphoton resonance: the π0. Numerous studies have pointed out that the hint of a new diphoton resonance at 750 GeV could be a pion analog, identified with the pseudo-Nambu-Goldstone boson of a chiral symmetry spontaneously broken by new strong dynamics at the TeV scale. These “hypercolor” models are generically expected to violate parity through a topological angle θ~. We discuss the physics of θ~ and its impact on the phenomenology of the new sector. We also describe some of the theoretical implications of a nonzero θ~. In particular, θ~ can generate an O(1) threshold correction to the QCD vacuum angle θ near the TeV scale, sharply constraining ultraviolet solutions to the strong CP problem. Furthermore, finding that θ~ is small may be interpreted as evidence in favor of UV solutions to strong CP, particularly those based on spontaneously broken P or CP symmetries.

  18. A Strong Merger Shock in Abell 665

    NASA Technical Reports Server (NTRS)

    Dasadia, S.; Sun, M.; Sarazin, C.; Morandi, A.; Markevitch, M.; Wik, D.; Feretti, L.; Giovannini, G.; Govoni, F.

    2016-01-01

    Deep (103 ks) Chandra observations of Abell 665 have revealed rich structures in this merging galaxy cluster, including a strong shock and two cold fronts. The newly discovered shock has a Mach number of M =?3.0 +/- 0.6, propagating in front of a cold disrupted cloud. This makes Abell 665 the second cluster, after the Bullet cluster, where a strong merger shock of M is approximately 3 has been detected. The shock velocity from jump conditions is consistent with (2.7 +/- 0.7) × 10(exp 3) km s(exp -1). The new data also reveal a prominent southern cold front with potentially heated gas ahead of it. Abell 665 also hosts a giant radio halo. There is a hint of diffuse radio emission extending to the shock at the north, which needs to be examined with better radio data. This new strong shock provides a great opportunity to study the reacceleration model with the X-ray and radio data combined.

  19. Cosmology with Strong-lensing Systems

    NASA Astrophysics Data System (ADS)

    Cao, Shuo; Biesiada, Marek; Gavazzi, Raphaël; Piórkowska, Aleksandra; Zhu, Zong-Hong

    2015-06-01

    In this paper, we assemble a catalog of 118 strong gravitational lensing systems from the Sloan Lens ACS Survey, BOSS emission-line lens survey, Lens Structure and Dynamics, and Strong Lensing Legacy Survey and use them to constrain the cosmic equation of state. In particular, we consider two cases of dark energy phenomenology: the XCDM model, where dark energy is modeled by a fluid with constant w equation-of-state parameter, and in the Chevalier-Polarski-Linder (CPL) parameterization, where w is allowed to evolve with redshift, w(z)={{w}0}+{{w}1}\\frac{z}{1 + z} . We assume spherically symmetric mass distribution in lensing galaxies, but we relax the rigid assumption of the SIS model in favor of a more general power-law index γ, also allowing it to evolve with redshifts γ (z). Our results for the XCDM cosmology show agreement with values (concerning both w and γ parameters) obtained by other authors. We go further and constrain the CPL parameters jointly with γ (z). The resulting confidence regions for the parameters are much better than those obtained with a similar method in the past. They are also showing a trend of being complementary to the Type Ia supernova data. Our analysis demonstrates that strong gravitational lensing systems can be used to probe cosmological parameters like the cosmic equation of state for dark energy. Moreover, they have a potential to judge whether the cosmic equation of state evolved with time or not.

  20. Quantum Symmetries and Strong Haagerup Inequalities

    NASA Astrophysics Data System (ADS)

    Brannan, Michael

    2012-04-01

    In this paper, we consider families of operators {\\{x_r\\}_{r in Λ}} in a tracial C*-probability space {({mathcal{A}}, \\varphi)} , whose joint *-distribution is invariant under free complexification and the action of the hyperoctahedral quantum groups {\\{H_n^+\\}_{n in mathbb {N}}} . We prove a strong form of Haagerup's inequality for the non-self-adjoint operator algebra {{mathcal{B}}} generated by {\\{x_r\\}_{r in Λ}} , which generalizes the strong Haagerup inequalities for *-free R-diagonal families obtained by Kemp-Speicher (J Funct Anal 251:141-173, 2007). As an application of our result, we show that {{mathcal{B}}} always has the metric approximation property (MAP). We also apply our techniques to study the reduced C*-algebra of the free unitary quantum group {U_n^+} . We show that the non-self-adjoint subalgebra {{mathcal{B}}_n} generated by the matrix elements of the fundamental corepresentation of {U_n^+} has the MAP. Additionally, we prove a strong Haagerup inequality for {{mathcal{B}}_n} , which improves on the estimates given by Vergnioux's property RD (Vergnioux in J Oper Theory 57:303-324, 2007).

  1. Systematic errors in strong lens modeling

    NASA Astrophysics Data System (ADS)

    Johnson, Traci Lin; Sharon, Keren; Bayliss, Matthew B.

    2015-08-01

    The lensing community has made great strides in quantifying the statistical errors associated with strong lens modeling. However, we are just now beginning to understand the systematic errors. Quantifying these errors is pertinent to Frontier Fields science, as number counts and luminosity functions are highly sensitive to the value of the magnifications of background sources across the entire field of view. We are aware that models can be very different when modelers change their assumptions about the parameterization of the lensing potential (i.e., parametric vs. non-parametric models). However, models built while utilizing a single methodology can lead to inconsistent outcomes for different quantities, distributions, and qualities of redshift information regarding the multiple images used as constraints in the lens model. We investigate how varying the number of multiple image constraints and available redshift information of those constraints (ex., spectroscopic vs. photometric vs. no redshift) can influence the outputs of our parametric strong lens models, specifically, the mass distribution and magnifications of background sources. We make use of the simulated clusters by M. Meneghetti et al. and the first two Frontier Fields clusters, which have a high number of multiply imaged galaxies with spectroscopically-measured redshifts (or input redshifts, in the case of simulated clusters). This work will not only inform upon Frontier Field science, but also for work on the growing collection of strong lensing galaxy clusters, most of which are less massive and are capable of lensing a handful of galaxies, and are more prone to these systematic errors.

  2. Quantum processes in strong magnetic fields

    NASA Technical Reports Server (NTRS)

    Canuto, V.

    1975-01-01

    Quantum-mechanical processes that occur in a piece of matter embedded in a magnetic field with a strength of the order of 10 to the 13th power G are described which either are entirely due to the presence of the field or become modified because of it. The conversion of rotational energy into electromagnetic energy in pulsars is analyzed as a mechanism for producing such a field, and it is shown that a strong magnetic field is not sufficient for quantum effects to play a significant role; in addition, the density must be adjusted to be as low as possible. The pressure and energy density of a free electron gas in a uniform magnetic field are evaluated, neutron beta-decay in the presence of a strong field is examined, and the effect of such a field on neutrino reactions is discussed. The thermal history of a neutron star is studied, and it is concluded that a strong magnetic field helps to increase the cooling rate of the star by producing new channels through which neutrinos can carry away energy.

  3. Phase transition transistors based on strongly-correlated materials

    NASA Astrophysics Data System (ADS)

    Nakano, Masaki

    2013-03-01

    The field-effect transistor (FET) provides electrical switching functions through linear control of the number of charges at a channel surface by external voltage. Controlling electronic phases of condensed matters in a FET geometry has long been a central issue of physical science. In particular, FET based on a strongly correlated material, namely ``Mott transistor,'' has attracted considerable interest, because it potentially provides gigantic and diverse electronic responses due to a strong interplay between charge, spin, orbital and lattice. We have investigated electric-field effects on such materials aiming at novel physical phenomena and electronic functions originating from strong correlation effects. Here we demonstrate electrical switching of bulk state of matter over the first-order metal-insulator transition. We fabricated FETs based on VO2 with use of a recently developed electric-double-layer transistor technique, and found that the electrostatically induced carriers at a channel surface drive all preexisting localized carriers of 1022 cm-3 even inside a bulk to motion, leading to bulk carrier delocalization beyond the electrostatic screening length. This non-local switching of bulk phases is achieved with just around 1 V, and moreover, a novel non-volatile memory like character emerges in a voltage-sweep measurement. These observations are apparently distinct from those of conventional FETs based on band insulators, capturing the essential feature of collective interactions in strongly correlated materials. This work was done in collaboration with K. Shibuya, D. Okuyama, T. Hatano, S. Ono, M. Kawasaki, Y. Iwasa, and Y. Tokura. This work was supported by the Japan Society for the Promotion of Science (JSAP) through its ``Funding Program for World-Leading Innovative R&D on Science and Technology (FIRST Program).''

  4. Engaging Military Fathers in a Reflective Parenting Program: Lessons from Strong Families Strong Forces

    ERIC Educational Resources Information Center

    DeVoe, Ellen R.; Paris, Ruth

    2015-01-01

    Through Strong Families Strong Forces, a reflective parenting program for military families with young children, we were privileged to work with contemporary military fathers who served in the post-9/11 conflicts in Afghanistan and Iraq. Due to this work, the authors gained valuable insight into the complexity of fathering during wartime, the…

  5. Is strong reciprocity really strong in the lab, let alone in the real world?

    PubMed

    Güney, Şule; Newell, Ben R

    2012-02-01

    We argue that standard experiments supporting the existence of "strong reciprocity" do not represent many cooperative situations outside the laboratory. More representative experiments that incorporate "earned" rather than "windfall" wealth also do not provide evidence for the impact of strong reciprocity on cooperation in contemporary real-life situations or in evolutionary history, supporting the main conclusions of the target article.

  6. Prevention of strong earthquakes: Goal or utopia?

    NASA Astrophysics Data System (ADS)

    Mukhamediev, Sh. A.

    2010-11-01

    In the present paper, we consider ideas suggesting various kinds of industrial impact on the close-to-failure block of the Earth’s crust in order to break a pending strong earthquake (PSE) into a number of smaller quakes or aseismic slips. Among the published proposals on the prevention of a forthcoming strong earthquake, methods based on water injection and vibro influence merit greater attention as they are based on field observations and the results of laboratory tests. In spite of this, the cited proofs are, for various reasons, insufficient to acknowledge the proposed techniques as highly substantiated; in addition, the physical essence of these methods has still not been fully understood. First, the key concept of the methods, namely, the release of the accumulated stresses (or excessive elastic energy) in the source region of a forthcoming strong earthquake, is open to objection. If we treat an earthquake as a phenomenon of a loss in stability, then, the heterogeneities of the physicomechanical properties and stresses along the existing fault or its future trajectory, rather than the absolute values of stresses, play the most important role. In the present paper, this statement is illustrated by the classical examples of stable and unstable fractures and by the examples of the calculated stress fields, which were realized in the source regions of the tsunamigenic earthquakes of December 26, 2004 near the Sumatra Island and of September 29, 2009 near the Samoa Island. Here, just before the earthquakes, there were no excessive stresses in the source regions. Quite the opposite, the maximum shear stresses τmax were close to their minimum value, compared to τmax in the adjacent territory. In the present paper, we provide quantitative examples that falsify the theory of the prevention of PSE in its current form. It is shown that the measures for the prevention of PSE, even when successful for an already existing fault, can trigger or accelerate a catastrophic

  7. Gutzwiller approximation in strongly correlated electron systems

    NASA Astrophysics Data System (ADS)

    Li, Chunhua

    Gutzwiller wave function is an important theoretical technique for treating local electron-electron correlations nonperturbatively in condensed matter and materials physics. It is concerned with calculating variationally the ground state wave function by projecting out multi-occupation configurations that are energetically costly. The projection can be carried out analytically in the Gutzwiller approximation that offers an approximate way of calculating expectation values in the Gutzwiller projected wave function. This approach has proven to be very successful in strongly correlated systems such as the high temperature cuprate superconductors, the sodium cobaltates, and the heavy fermion compounds. In recent years, it has become increasingly evident that strongly correlated systems have a strong propensity towards forming inhomogeneous electronic states with spatially periodic superstrutural modulations. A good example is the commonly observed stripes and checkerboard states in high- Tc superconductors under a variety of conditions where superconductivity is weakened. There exists currently a real challenge and demand for new theoretical ideas and approaches that treats strongly correlated inhomogeneous electronic states, which is the subject matter of this thesis. This thesis contains four parts. In the first part of the thesis, the Gutzwiller approach is formulated in the grand canonical ensemble where, for the first time, a spatially (and spin) unrestricted Gutzwiller approximation (SUGA) is developed for studying inhomogeneous (both ordered and disordered) quantum electronic states in strongly correlated electron systems. The second part of the thesis applies the SUGA to the t-J model for doped Mott insulators which led to the discovery of checkerboard-like inhomogeneous electronic states competing with d-wave superconductivity, consistent with experimental observations made on several families of high-Tc superconductors. In the third part of the thesis, new

  8. Unified Time and Frequency Picture of Ultrafast Atomic Excitation in Strong Laser Fields.

    PubMed

    Zimmermann, H; Patchkovskii, S; Ivanov, M; Eichmann, U

    2017-01-06

    Excitation and ionization in strong laser fields lies at the heart of such diverse research directions as high-harmonic generation and spectroscopy, laser-induced diffraction imaging, emission of femtosecond electron bunches from nanotips, self-guiding, filamentation and mirrorless lasing during propagation of light in atmospheres. While extensive quantum mechanical and semiclassical calculations on strong-field ionization are well backed by sophisticated experiments, the existing scattered theoretical work aiming at a full quantitative understanding of strong-field excitation lacks experimental confirmation. Here we present experiments on strong-field excitation in both the tunneling and multiphoton regimes and their rigorous interpretation by time dependent Schrödinger equation calculations, which finally consolidates the seemingly opposing strong-field regimes with their complementary pictures. Most strikingly, we observe an unprecedented enhancement of excitation yields, which opens new possibilities in ultrafast strong-field control of Rydberg wave packet excitation and laser intensity characterization.

  9. Unified Time and Frequency Picture of Ultrafast Atomic Excitation in Strong Laser Fields

    NASA Astrophysics Data System (ADS)

    Zimmermann, H.; Patchkovskii, S.; Ivanov, M.; Eichmann, U.

    2017-01-01

    Excitation and ionization in strong laser fields lies at the heart of such diverse research directions as high-harmonic generation and spectroscopy, laser-induced diffraction imaging, emission of femtosecond electron bunches from nanotips, self-guiding, filamentation and mirrorless lasing during propagation of light in atmospheres. While extensive quantum mechanical and semiclassical calculations on strong-field ionization are well backed by sophisticated experiments, the existing scattered theoretical work aiming at a full quantitative understanding of strong-field excitation lacks experimental confirmation. Here we present experiments on strong-field excitation in both the tunneling and multiphoton regimes and their rigorous interpretation by time dependent Schrödinger equation calculations, which finally consolidates the seemingly opposing strong-field regimes with their complementary pictures. Most strikingly, we observe an unprecedented enhancement of excitation yields, which opens new possibilities in ultrafast strong-field control of Rydberg wave packet excitation and laser intensity characterization.

  10. Effects of Strong Scattering on Transionospheric Propagation

    DTIC Science & Technology

    1989-09-01

    neutral atmospheric winds , neutral atmospheric acoustic gravity waves, and the interaction of the earth’s magnetic field with induced electric fields...F" is used to describe a scattering phenomenon in which F-region ionograms show echoes which are spread over a range of heights or frequencies. When a...produce the spread-F signature on ionograms (Fejer, Kelley, 1980). Once formed, the bubbles rise to heights above the F-layer peak, where they produce

  11. Strong correlations in actinide redox reactions

    NASA Astrophysics Data System (ADS)

    Horowitz, S. E.; Marston, J. B.

    2011-02-01

    Reduction-oxidation (redox) reactions of the redox couples An(VI)/An(V), An(V)/An(IV), and An(IV)/An(III), where An is an element in the family of early actinides (U, Np, and Pu), as well as Am(VI)/Am(V) and Am(V)/Am(III), are modeled by combining density functional theory with a generalized Anderson impurity model that accounts for the strong correlations between the 5f electrons. Diagonalization of the Anderson impurity model yields improved estimates for the redox potentials and the propensity of the actinide complexes to disproportionate.

  12. Vacuum orientations in strong CP violation

    SciTech Connect

    Huang, Zheng; Viswanathan, K.S.; Wu, Dan-di

    1991-12-01

    We study the QCD vacuum orientation angles in correlation with the strong CP phases. A vacuum alignment equation of the dynamical chiral symmetry breaking is derived based on the anomalous Ward identity. It is emphasized that a chiral rotation of the quark field causes a change of the vacuum orientation and a change in the definition of the light pseudoscalar generators. As an illustration of the idea, {eta} {yields} 2{pi} decays are carefully studied in different chiral frames and shown to be independent of. chiral rotations.

  13. Obama Indicates Strong Support for Science

    NASA Astrophysics Data System (ADS)

    Showstack, Randy

    2009-05-01

    In remarks delivered at the U.S. National Academy of Sciences (NAS) annual meeting on 27 April, U.S. President Barack Obama indicated his administration's strong support for science and for pursuing a clean energy economy. He also announced a goal that the United States “will devote more than 3% of our [gross domestic product] to research and development.” “This represents the largest commitment to scientific research and innovation in American history,” Obama said, noting that the American Recovery and Reinvestment Act already is providing the nation with its largest single boost to investment in basic research.

  14. Fundamental Structure of Matter and Strong Interaction

    SciTech Connect

    Jian-Ping Chen

    2011-11-01

    More than 99% of the visible matter in the universe are the protons and neutrons. Their internal structure is mostly governed by the strong interaction. Understanding their internal structure in terms of fundamental degrees-of-freedom is one of the most important subjects in modern physics. Worldwide efforts in the last few decades have lead to numerous surprises and discoveries, but major challenges still remain. An overview of the progress will be presented with a focus on the recent studies of the proton and neutron's electromagnetic and spin structure. Future perspectives will be discussed.

  15. Strong Interaction Studies with PANDA at FAIR

    NASA Astrophysics Data System (ADS)

    Schönning, Karin

    2016-10-01

    The Facility for Antiproton and Ion Research (FAIR) in Darmstadt, Germany, provides unique possibilities for a new generation of nuclear-, hadron- and atomic physics experiments. The future PANDA experiment at FAIR will offer a broad physics programme with emphasis on different aspects of hadron physics. Understanding the strong interaction in the perturbative regime remains one of the greatest challenges in contemporary physics and hadrons provide several important keys. In these proceedings, PANDA will be presented along with some high-lights of the planned physics programme.

  16. Hypervelocity Plasmas with Strong MHD (Magnetohydrodynamic) Interactions.

    DTIC Science & Technology

    1984-12-01

    ARD-Ai5S 867 HYPERVELOCITY PLASMAS WITH STRONG NHD j/j (MAGNETOHYDRODYNANIC) INTERRCTIONS(U) STD RESEARCH CORP ARCADIA CA S T DEMETRIADES FT AL DEC...MIRCP RSLTO-TS HR NAINLBUEUO SADRS-16- -ArO’ mi -T7- (7 % STD RESEARCH CORPORATION POST OFFICE OX ’C’ ARC ADIA, CALIFORNIA 91006 LTf.LEPHONE! (213...Covered: 1 June 1983 -31 May 1984 December 1984 STD Research Corporation P.O. Box "’C" Arcadia, California 91006 Appi-u ’, 2 I~t or1 ’Pub I rege

  17. Understanding strongly coupling magnetism from holographic duality

    NASA Astrophysics Data System (ADS)

    Cai, Rong-Gen; Yang, Run-Qiu

    2016-07-01

    The unusual magnetic materials are significant in both science and technology. However, because of the strongly correlated effects, it is difficult to understand their novel properties from theoretical aspects. Holographic duality offers a new approach to understanding such systems from gravity side. This paper will give a brief review of our recent works on the applications of holographic duality in understanding unusual magnetic materials. Some quantitative comparision between holographic results and experimental data will be shown and some predictions from holographic duality models will be discussed.

  18. Strong correlations in actinide redox reactions.

    PubMed

    Horowitz, S E; Marston, J B

    2011-02-14

    Reduction-oxidation (redox) reactions of the redox couples An(VI)/An(V), An(V)/An(IV), and An(IV)/An(III), where An is an element in the family of early actinides (U, Np, and Pu), as well as Am(VI)/Am(V) and Am(V)/Am(III), are modeled by combining density functional theory with a generalized Anderson impurity model that accounts for the strong correlations between the 5f electrons. Diagonalization of the Anderson impurity model yields improved estimates for the redox potentials and the propensity of the actinide complexes to disproportionate.

  19. Bose Polarons in the Strongly Interacting Regime

    NASA Astrophysics Data System (ADS)

    Hu, Ming-Guang; Van de Graaff, Michael J.; Kedar, Dhruv; Corson, John P.; Cornell, Eric A.; Jin, Deborah S.

    2016-07-01

    When an impurity is immersed in a Bose-Einstein condensate, impurity-boson interactions are expected to dress the impurity into a quasiparticle, the Bose polaron. We superimpose an ultracold atomic gas of 87Rb with a much lower density gas of fermionic 40 impurities. Through the use of a Feshbach resonance and radio-frequency spectroscopy, we characterize the energy, spectral width, and lifetime of the resultant polaron on both the attractive and the repulsive branches in the strongly interacting regime. The width of the polaron in the attractive branch is narrow compared to its binding energy, even as the two-body scattering length diverges.

  20. SENTINEL-1 Image Matching Using Strong Scatters

    NASA Astrophysics Data System (ADS)

    Ghannadi, M. A.; Saadatseresht, M.; Motagh, M.

    2015-12-01

    The availability of new radar spaceborne sensors offers new interesting potentialities for the geomatics application: spatial and temporal change detection, generation of Digital Elevation Model(DEM) using radargrametry and interferometry. Since the start of the sentinel-1 mission to take images from different regions all over the world, the ability to use these images in variety domains has been treasured. This paper suggests a method for image matching using strong scatters. all the experiments are done on sentinel-1 stereo images from Jam, Bushehr, Iran.

  1. Why so strong for the lotus leaf?

    NASA Astrophysics Data System (ADS)

    Guo, Zhiguang; Liu, Weimin; Su, Bao-Lian

    2008-11-01

    The authors discussed the potential reasons why the lotus leaf is so strong by means of scanning electron microscopy (SEM). The results showed that the good mechanical properties of lotus leaf should be attributed to its architecture, such as paralleled microtubes structure, umbrellalike structure, and hierarchically layered hexagon structure. The important observation from this work is that the surface of the rear face of the lotus leaf seems to be constituted by the layers of hexagons whose hierarchical pilling up of size decreases as we go deeper from surface. This is a typical fractal-like phenomenon.

  2. Multimode Strong Coupling in Circuit QED

    NASA Astrophysics Data System (ADS)

    Sundaresan, Neereja; Liu, Yanbing; Sadri, Darius; Szocs, Laszlo; Underwood, Devin; Malekakhlagh, Moein; Tureci, Hakan; Houck, Andrew

    We present experimental and theoretical studies in the multimode strong coupling (MMSC) regime of cavity quantum electrodynamics (QED). In MMSC, a single atom is simultaneously coupled to a large, but discrete, number of cavity harmonics, with atom-mode coupling strengths comparable to the free spectral range (FSR). This regime is readily accessible in circuit QED, by strongly coupling a transmon qubit to a low fundamental frequency microwave cavity. We present some key results from our original experiment (PRX 5, 021035, 2015), in which a transmon qubit, resonant with the 75th harmonic of a 90 MHz cavity, reached qubit-mode coupling strengths exceeding 30MHz. When this system is coherently driven, we observed complex multimode fluorescence, with the notable formation of ultra-narrow linewidths. To better understand these unique features of multimode resonance fluorescence we developed a quantum formalism, which attributes the spectral linewidth narrowing to the correlated spontaneous emission of doubly dressed states. Finally we will share preliminary experimental results from our continuing study of MMSC, this time from a system where qubit-mode coupling strengths approach and even exceed the FSR.

  3. An engineered strong promoter for streptomycetes.

    PubMed

    Wang, Weishan; Li, Xiao; Wang, Juan; Xiang, Sihai; Feng, Xiaozhou; Yang, Keqian

    2013-07-01

    Well-characterized promoters are essential tools for metabolic engineering and synthetic biology. In Streptomyces coelicolor, the native kasOp is a temporally expressed promoter strictly controlled by two regulators, ScbR and ScbR2. In this work, first, kasOp was engineered to remove a common binding site of ScbR and ScbR2 upstream of its core region, thus generating a stronger promoter, kasOp3. Second, another ScbR binding site internal to the kasOp3 core promoter region was abolished by random mutation and screening of the mutant library to obtain the strongest promoter, kasOp* (where the asterisk is used to distinguish the engineered promoter from the native promoter). The activities of kasOp* were compared with those of two known strong promoters, ermEp* and SF14p, in three Streptomyces species. kasOp* showed the highest activity at the transcription and protein levels in all three hosts. Furthermore, relative to ermEp* and SF14p, kasOp* was shown to confer the highest actinorhodin production level when used to drive the expression of actII-ORF4 in S. coelicolor. Therefore, kasOp* is a simple and well-defined strong promoter useful for gene overexpression in streptomycetes.

  4. Proton tautomerism for strong polarization switching

    NASA Astrophysics Data System (ADS)

    Horiuchi, Sachio; Kobayashi, Kensuke; Kumai, Reiji; Ishibashi, Shoji

    2017-02-01

    Ferroelectrics based on proton tautomerism are promising in low-field and above-room-temperature operations. Here seven organic ferroelectric crystals are examined to search for efficient switching of strong spontaneous polarization on proton tautomerism. Solution-grown crystals exhibit strong pinning of ferroelectric domain walls, but excellent switching performance is awakened by depinning domain walls under thermal annealing and/or repetitive bipolar pulses with a high voltage. Compared with ferroelectric polymers such as polyvinylidefluoride, the optimized polarizations are comparable or stronger in magnitude whereas the coercive fields are two orders of magnitude weaker. The polarization of croconic acid, in particular, breaks its own record for organic systems in increasing from 21 to 30 μC cm-2 and now exceeds those of some commercial ferroelectric materials such as SrBi2Ta2O9 and BaTiO3. Optimization reduces the discrepancy of the spontaneous polarization with the results of the first-principles calculations to less than 15%. The cooperative roles of proton transfer and π-bond switching are discussed by employing the point-charge model and hydrogen-bond geometry.

  5. A metafluid exhibiting strong optical magnetism.

    PubMed

    Sheikholeslami, Sassan N; Alaeian, Hadiseh; Koh, Ai Leen; Dionne, Jennifer A

    2013-09-11

    Advances in the field of metamaterials have enabled unprecedented control of light-matter interactions. Metamaterial constituents support high-frequency electric and magnetic dipoles, which can be used as building blocks for new materials capable of negative refraction, electromagnetic cloaking, strong visible-frequency circular dichroism, and enhancing magnetic or chiral transitions in ions and molecules. While all metamaterials to date have existed in the solid-state, considerable interest has emerged in designing a colloidal metamaterial or "metafluid". Such metafluids would combine the advantages of solution-based processing with facile integration into conventional optical components. Here we demonstrate the colloidal synthesis of an isotropic metafluid that exhibits a strong magnetic response at visible frequencies. Protein-antibody interactions are used to direct the solution-phase self-assembly of discrete metamolecules comprised of silver nanoparticles tightly packed around a single dielectric core. The electric and magnetic response of individual metamolecules and the bulk metamaterial solution are directly probed with optical scattering and spectroscopy. Effective medium calculations indicate that the bulk metamaterial exhibits a negative effective permeability and a negative refractive index at modest fill factors. This metafluid can be synthesized in large-quantity and high-quality and may accelerate development of advanced nanophotonic and metamaterial devices.

  6. Coping with strongly coupled string theory

    NASA Astrophysics Data System (ADS)

    Banks, Tom; Dine, Michael

    1994-12-01

    String theory, if it describes nature, is probably strongly coupled. As a result, one might despair of making any statements about the theory. In the framework of a set of clearly spelled out assumptions, we show that this is not necessarily the case. Certain discrete gauge symmetries, combined with supersymmetry, tightly constrain the form of the effective action. Among our assumptions are that the true ground state can be obtained from some perturbative ground state by varying the coupling, and that the actual numerical value of the low energy field-theoretic coupling g2/4π is small. It follows that the low energy theory is approximately supersymmetric; corrections to the superpotential and gauge coupling function are small, while corrections to the Kahler potential are large; the spectrum of light particles is the same at strong as at weak coupling. We survey the phenomenological consequences of this viewpoint. We also note that the string axion can serve as a QCD axion in this framework (modulo cosmological problems).

  7. The Athens Acropolis Strong Motion Array

    NASA Astrophysics Data System (ADS)

    Kalogeras, I. S.; Evangelidis, C. P.; Melis, N. S.; Boukouras, K.

    2012-04-01

    During the last decades, extensive restoration works through a dedicated "Acropolis Restoration Service" (YSMA) take place in the Acropolis, the greatest sanctuary of ancient Athens. Since 2008, a permanent strong motion array was deployed by the Institute of Geodynamics, National Observatory of Athens (NOA-IG) in collaboration with YSMA. Free field installations were decided at sites showing various characteristics, aiming to investigate differences in geotechnical properties as well as the structure response of Parthenon itself. The installation phase is presented, with the techniques used to overcome difficulties (i.e. extreme weather conditions, power and communication limitations, restoration works and visitors) and the special care taken for the specific archaeological site. Furthermore, indicative examples of seismic events recorded by the array are analyzed and the complexity of the hill and the monument is made apparent. Among them, the long distance events of Tohoku, Japan 2010 and Van, Turkey 2011, some regional moderate earthquakes in Greece and some weak earthquakes from the vicinity. Continuous ambient noise monitoring using PQLX software gives some first indicative results, showing a variety of characteristics at installation sites. Finally, further developments and future steps are presented such as: the extension of the array, the integration of seismic data within the GIS platform of YSMA at the site and the use of strong motion records, in conjunction with data from other monitoring systems operating in Acropolis for the study of specific monuments.

  8. Strong interaction physics from hadronic atoms

    NASA Astrophysics Data System (ADS)

    Batty, C. J.; Friedman, E.; Gal, A.

    1997-08-01

    Hadronic atoms provide a unique laboratory for studying strong interactions and nuclear medium effects at zero kinetic energy. Previous results from analyses of strong-interaction data consisting of level shifts, widths and yields in π-, K -, p¯ and ∑ - atoms are reviewed. Recent results from fits to comprehensive sets of data in terms of density-dependent optical potentials that respect the low-density limit, where the interaction tends to the free hadron nucleon value, are discussed. The importance of using realistic nuclear density distributions is highlighted. The introduction of density dependence in most cases significantly improves the fit to the data and leads to some novel results. For K - atoms, a substantial attraction of order 200 MeV in nuclear matter is suggested, with interesting repercussions for K¯ condensation and the evolution of strangeness in high-density stars. For p¯ atoms it is found that a reasonable p-wave strength can be accommodated in the fitted optical potential, in agreement with the energy dependence observed for some low-energy p¯N reactions. For ∑ - atoms, the fitted potential becomes repulsive inside the nucleus, implying that Σ hyperons generally do not bind in nuclei in agreement with recent measurements. This repulsion significantly affects calculated masses of neutron stars.

  9. An Engineered Strong Promoter for Streptomycetes

    PubMed Central

    Wang, Weishan; Li, Xiao; Wang, Juan; Xiang, Sihai; Feng, Xiaozhou

    2013-01-01

    Well-characterized promoters are essential tools for metabolic engineering and synthetic biology. In Streptomyces coelicolor, the native kasOp is a temporally expressed promoter strictly controlled by two regulators, ScbR and ScbR2. In this work, first, kasOp was engineered to remove a common binding site of ScbR and ScbR2 upstream of its core region, thus generating a stronger promoter, kasOp3. Second, another ScbR binding site internal to the kasOp3 core promoter region was abolished by random mutation and screening of the mutant library to obtain the strongest promoter, kasOp* (where the asterisk is used to distinguish the engineered promoter from the native promoter). The activities of kasOp* were compared with those of two known strong promoters, ermEp* and SF14p, in three Streptomyces species. kasOp* showed the highest activity at the transcription and protein levels in all three hosts. Furthermore, relative to ermEp* and SF14p, kasOp* was shown to confer the highest actinorhodin production level when used to drive the expression of actII-ORF4 in S. coelicolor. Therefore, kasOp* is a simple and well-defined strong promoter useful for gene overexpression in streptomycetes. PMID:23686264

  10. Caviton dynamics in strong Langmuir turbulence

    SciTech Connect

    DuBois, D.; Rose, H.A.; Russell, D.

    1989-01-01

    Recent studies based on long time computer simulations of Langmuir turbulence as described by Zakharov's model will be reviewed. These show that for strong to moderate ion sound samping the turbulent energy is dominantly in nonlinear ''caviton'' excitations which are localized in space and time. A local caviton model will be presented which accounts for the nucleation-collapse-burnout cycles of individual cavitons as well as their space-time correlations. This model is in detailed agreement with many features of the electron density fluctuation spectra in the ionosphere modified by powerful hf waves as measured by incoherent scatter radar. Recently such observations have verified a prediction of the theory that ''free'' Langmuir waves are emitted in the caviton collapse process. These observations and theoretical considerations also strongly imply that cavitons in the heated ionosphere, under certain conditions, evolve to states in which they are ordered in space and time. The sensitivity of the high frequency Langmuir field dynamics to the low frequency ion density fluctuations and the related caviton nucleation process will be discussed. 40 refs., 19 figs.

  11. The evolution of strong reproductive isolation.

    PubMed

    Barton, Nicholas H; de Cara, Maria Angeles Rodriguez

    2009-05-01

    Felsenstein distinguished two ways by which selection can directly strengthen isolation. First, a modifier that strengthens prezygotic isolation can be favored everywhere. This fits with the traditional view of reinforcement as an adaptation to reduce deleterious hybridization by strengthening assortative mating. Second, selection can favor association between different incompatibilities, despite recombination. We generalize this "two allele" model to follow associations among any number of incompatibilities, which may include both assortment and hybrid inviability. Our key argument is that this process, of coupling between incompatibilities, may be quite different from the usual view of reinforcement: strong isolation can evolve through the coupling of any kind of incompatibility, whether prezygotic or postzygotic. Single locus incompatibilities become coupled because associations between them increase the variance in compatibility, which in turn increases mean fitness if there is positive epistasis. Multiple incompatibilities, each maintained by epistasis, can become coupled in the same way. In contrast, a single-locus incompatibility can become coupled with loci that reduce the viability of haploid hybrids because this reduces harmful recombination. We obtain simple approximations for the limits of tight linkage, and strong assortment, and show how assortment alleles can invade through associations with other components of reproductive isolation.

  12. Hofstadter's Butterfly in the strongly interacting regime

    NASA Astrophysics Data System (ADS)

    Dean, Cory

    2015-03-01

    In 1976, Douglas Hofstadter predicted that in the presence of both a strong magnetic field, and a spatially varying periodic potential, Bloch electrons confined to a 2D quantum well exhibit a self-similar fractal energy spectrum known as the ``Hofstadter's Butterfly.'' In subsequent years, experimental discovery of the quantum Hall effect gave birth to an expansive field of research into 2D electronic systems in the presence of a magnetic field, however, direct confirmation of the fractal spectrum remained elusive. Recently we demonstrated that graphene, in which Bloch electrons can be described by Dirac fermions, provides a new opportunity to investigate this nearly 40 year old problem. In this talk I will discuss the experimental realization of Hofstader's butterfly by exploiting nano-scale interfacial effects between graphene and hexagonal boron nitride substrates, together with application of extremely high magnetic fields. Utilizing newly developed techniques to fabricate ultra-clean graphene devices, I will additionally demonstrate the capability to probe for the first time the effect of strong electron interactions within the fractal Hofstadter spectrum.

  13. Proton tautomerism for strong polarization switching

    PubMed Central

    Horiuchi, Sachio; Kobayashi, Kensuke; Kumai, Reiji; Ishibashi, Shoji

    2017-01-01

    Ferroelectrics based on proton tautomerism are promising in low-field and above-room-temperature operations. Here seven organic ferroelectric crystals are examined to search for efficient switching of strong spontaneous polarization on proton tautomerism. Solution-grown crystals exhibit strong pinning of ferroelectric domain walls, but excellent switching performance is awakened by depinning domain walls under thermal annealing and/or repetitive bipolar pulses with a high voltage. Compared with ferroelectric polymers such as polyvinylidefluoride, the optimized polarizations are comparable or stronger in magnitude whereas the coercive fields are two orders of magnitude weaker. The polarization of croconic acid, in particular, breaks its own record for organic systems in increasing from 21 to 30 μC cm−2 and now exceeds those of some commercial ferroelectric materials such as SrBi2Ta2O9 and BaTiO3. Optimization reduces the discrepancy of the spontaneous polarization with the results of the first-principles calculations to less than 15%. The cooperative roles of proton transfer and π-bond switching are discussed by employing the point-charge model and hydrogen-bond geometry. PMID:28205550

  14. Fragmentation of negative ions in a strong laser field

    NASA Astrophysics Data System (ADS)

    Berry, Ben; Jochim, Bethany; Severt, T.; Feizollah, Peyman; Rajput, Jyoti; Hayes, D.; Carnes, K. D.; Esry, B. D.; Ben-Itzhak, I.

    2016-05-01

    The fragmentation of negative ions in a strong laser field can provide a testing ground for a variety of unique phenomena. For example, anions with a loosely bound electron allow for the study of rescattering phenomena at lower laser intensities than for neutral targets. We study the behavior of keV anion beams in an ultrafast, intense laser field. The use of a fast-beam target facilitates the measurement of neutral fragments. This capability allows us to explore laser-induced dynamics in both ionic and neutral charge states. Using a coincidence 3D momentum imaging technique, we obtain the full 3D momentum of all nuclear fragments. In this preliminary work, we study atomic (H-) and molecular (H2-,F2-)systems with the goal of identifying and controlling their fragmentation pathways. This work was supported by the Chemical Sciences, Geosciences, and Biosciences Division, Office of Basic Energy Sciences, Office of Science, U.S. Department of Energy.

  15. Crustal failure on icy Moons from a strong tidal encounter

    NASA Astrophysics Data System (ADS)

    Quillen, Alice C.; Giannella, David; Shaw, John G.; Ebinger, Cynthia

    2016-09-01

    Close tidal encounters among large planetesimals and Moons should have been more common than grazing or normal impacts. Using a mass spring model within an N-body simulation, we simulate the deformation of the surface of an elastic spherical body caused by a close parabolic tidal encounter with a body that has similar mass as that of the primary body. Such an encounter can induce sufficient stress on the surface to cause brittle failure of an icy crust and simulated fractures can extend a large fraction of the radius of body. Strong tidal encounters may be responsible for the formation of long graben complexes and chasmata in ancient terrain of icy Moons such as Dione, Tethys, Ariel and Charon.

  16. Spontaneous parity violation and SUSY strong gauge theory

    SciTech Connect

    Haba, Naoyuki; Ohki, Hiroshi

    2012-07-27

    We suggest simple models of spontaneous parity violation in supersymmetric strong gauge theory. We focus on left-right symmetric model and investigate vacuum with spontaneous parity violation. Non-perturbative effects are calculable in supersymmetric gauge theory, and we suggest new models. Our models show confinement, so that we try to understand them by using a dual description of the theory. The left-right symmetry breaking and electroweak symmetry breaking are simultaneously occurred with the suitable energy scale hierarchy. This structure has several advantages compared to the MSSM. The scale of the Higgs mass (left-right breaking scale) and that of VEVs are different, so the SUSY little hierarchy problems are absent. The second model also induces spontaneous supersymmetry breaking.

  17. Turbulent Magnetic Field Amplification behind Strong Shock Waves in GRB and SNR

    NASA Astrophysics Data System (ADS)

    Inoue, Tsuyoshi

    2012-09-01

    Using three-dimensional (special relativistic) magnetohydrodynamics simulations, the amplification of magnetic field behind strong shock wave is studied. In supernova remnants and gamma-ray bursts, strong shock waves propagate through an inhomogeneous density field. When the shock wave hit a density bump or density dent, the Richtmyer-Meshkov instability is induced that cause a deformation of the shock front. The deformed shock leaves vorticity behind the shock wave that amplifies the magnetic field due to the stretching of field lines.

  18. BOOK REVIEW: Physics of Strongly Coupled Plasma

    NASA Astrophysics Data System (ADS)

    Kraeft, Wolf-Dietrich

    2007-07-01

    Strongly coupled plasmas (or non-ideal plasmas) are multi-component charged many-particle systems, in which the mean value of the potential energy of the system is of the same order as or even higher than the mean value of the kinetic energy. The constituents are electrons, ions, atoms and molecules. Dusty (or complex) plasmas contain still mesoscopic (multiply charged) particles. In such systems, the effects of strong coupling (non-ideality) lead to considerable deviations of physical properties from the corresponding properties of ideal plasmas, i.e., of plasmas in which the mean kinetic energy is essentially larger than the mean potential energy. For instance, bound state energies become density dependent and vanish at higher densities (Mott effect) due to the interaction of the pair with the surrounding particles. Non-ideal plasmas are of interest both for general scientific reasons (including, for example, astrophysical questions), and for technical applications such as inertially confined fusion. In spite of great efforts both experimentally and theoretically, satisfactory information on the physical properties of strongly coupled plasmas is not at hand for any temperature and density. For example, the theoretical description of non-ideal plasmas is possible only at low densities/high temperatures and at extremely high densities (high degeneracy). For intermediate degeneracy, however, numerical experiments have to fill the gap. Experiments are difficult in the region of `warm dense matter'. The monograph tries to present the state of the art concerning both theoretical and experimental attempts. It mainly includes results of the work perfomed in famous Russian laboratories in recent decades. After outlining basic concepts (chapter 1), the generation of plasmas is considered (chapter 2, chapter 3). Questions of partial (chapter 4) and full ionization (chapter 5) are discussed including Mott transition and Wigner crystallization. Electrical and optical

  19. Strong correlations in gravity and biophysics

    NASA Astrophysics Data System (ADS)

    Krotov, Dmitry

    The unifying theme of this dissertation is the use of correlations. In the first part (chapter 2), we investigate correlations in quantum field theories in de Sitter space. In the second part (chapters 3,4,5), we use correlations to investigate a theoretical proposal that real (observed in nature) transcriptional networks of biological organisms are operating at a critical point in their phase diagram. In chapter 2 we study the infrared dependence of correlators in various external backgrounds. Using the Schwinger-Keldysh formalism we calculate loop corrections to the correlators in the case of the Poincare patch and the complete de Sitter space. In the case of the Poincare patch, the loop correction modifies the behavior of the correlator at large distances. In the case of the complete de Sitter space, the loop correction has a strong dependence on the infrared cutoff in the past. It grows linearly with time, suggesting that at some point the correlations become strong and break the symmetry of the classical background. In chapter 3 we derive the signatures of critical behavior in a model organism, the embryo of Drosophila melanogaster. They are: strong correlations in the fluctuations of different genes, a slowing of dynamics, long range correlations in space, and departures from a Gaussian distribution of these fluctuations. We argue that these signatures are observed experimentally. In chapter 4 we construct an effective theory for the zero mode in this system. This theory is different from the standard Landau-Ginsburg description. It contains gauge fields (the result of the broken translational symmetry inside the cell), which produce observable contributions to the two-point function of the order parameter. We show that the behavior of the two-point function for the network of N genes is described by the action of a relativistic particle moving on the surface of the N - 1 dimensional sphere. We derive a theoretical bound on the decay of the correlations and

  20. Utilizing Nanofabrication to Construct Strong, Luminescent Materials

    SciTech Connect

    Chen, Wei; Huang, Gang; Lu, Hong B.; McCready, David E.; Joly, Alan G.; Bovin, Jan-Olov

    2006-05-28

    Luminescent materials have been utilized widely in applications from lighting to sensing. The new development of technologies based on luminescence properties requires the materials to have high luminescence efficiency and mechanical strength. In this article, we report the fabrication of luminescent materials possessing high mechanical strength by nanofabrication with polyvinyl alcohol used as a stabilizer or coupling agent. X-ray diffraction and high resolution transmission microscope observations reveal that the nanocomposite sample contains ZnS and ZnO nanoparticles as well as kozoite and sodium nitrate. The mechanical strength and hardness of these nanocomposite materials are higher than polycarbonate and some carbon nanotube reinforced nanocomposites. Strong luminescence is observed in the new nanocomposites and the luminescence intensity does not degrade following up to 30 minutes of X-ray irradiation. Our results indicate that nanofabrication may provide a good method to improve the mechanical strength of luminescent materials for some applications in which high strength luminescent materials are needed.

  1. Strong quantum scarring by local impurities

    NASA Astrophysics Data System (ADS)

    Luukko, Perttu J. J.; Drury, Byron; Klales, Anna; Kaplan, Lev; Heller, Eric J.; Räsänen, Esa

    2016-11-01

    We discover and characterise strong quantum scars, or quantum eigenstates resembling classical periodic orbits, in two-dimensional quantum wells perturbed by local impurities. These scars are not explained by ordinary scar theory, which would require the existence of short, moderately unstable periodic orbits in the perturbed system. Instead, they are supported by classical resonances in the unperturbed system and the resulting quantum near-degeneracy. Even in the case of a large number of randomly scattered impurities, the scars prefer distinct orientations that extremise the overlap with the impurities. We demonstrate that these preferred orientations can be used for highly efficient transport of quantum wave packets across the perturbed potential landscape. Assisted by the scars, wave-packet recurrences are significantly stronger than in the unperturbed system. Together with the controllability of the preferred orientations, this property may be very useful for quantum transport applications.

  2. New strongly deformed proton emitter: 117La

    NASA Astrophysics Data System (ADS)

    Soramel, F.; Guglielmetti, A.; Stroe, L.; Müller, L.; Bonetti, R.; Poli, G. L.; Malerba, F.; Bianchi, E.; Andrighetto, A.; Guo, J. Y.; Li, Z. C.; Maglione, E.; Scarlassara, F.; Signorini, C.; Liu, Z. H.; Ruan, M.; Ivaşcu, M.; Broude, C.; Bednarczyk, P.; Ferreira, L. S.

    2001-03-01

    The decay by proton emission of the 117La nucleus has been studied via the 310 MeV 58Ni+64Zn reaction. The nucleus has two levels that decay to the ground state of 116Ba with Ep=783(6) keV (T1/2=22(5) ms] and Ep=933(10) keV [T1/2=10(5) ms]. Calculations performed for a deformed proton emitter reproduce quite well the experimental results confirming that 117La is strongly deformed (β2~0.3). Spin and parity of the two p-decaying levels have been determined as well: 3/2+ for the ground state and 9/2+ for the Ex=151(12) keV excited state.

  3. On a strong coupling property of QCD

    NASA Astrophysics Data System (ADS)

    Grandou, T.

    2017-03-01

    The fermionic Green's functions of QCD exhibit an unexpected property of effective locality, which appears to be exact, involving no approximation. In the limit of strong coupling, and at eikonal and quenching approximations (where this property was first discovered), effective locality implies a dependence of non-perturbative fermionic Green's functions on the full algebraic content of the rank 2-SUc(3) color algebra. At variance with Perturbation Theory and a variety of non-perturbative approaches also, C3-dependences show up, where C3 stands for the second, trilinear Casimir invariant of SUc(3). These dependences are sub-leading in magnitude and seem to comply with the maximally allowed departures from the pure C2 behaviours advocated by lattice numerical estimates.

  4. Strong-field ionization of lithium

    SciTech Connect

    Schuricke, Michael; Zhu Ganjun; Steinmann, Jochen; Simeonidis, Konstantinos; Dorn, Alexander; Ullrich, Joachim; Ivanov, Igor; Kheifets, Anatoli; Grum-Grzhimailo, Alexei N.; Bartschat, Klaus

    2011-02-15

    We report photoelectron energy spectra, momentum, and angular distributions for the strong-field single ionization of lithium by 30-fs laser pulses. For peak intensities between 10{sup 11} and 10{sup 14} W/cm{sup 2} at a central wavelength of 785 nm, the classical over-the-barrier intensity was reached well inside the multiphoton regime. The complete vector momenta of the ionization fragments were recorded by a reaction microscope with a magneto-optically trapped target (MOTREMI). On the theoretical side, the time-dependent Schroedinger equation was solved by two independent methods seeking the solution directly on a radial grid. Distinct differences between the results of both calculations and also in comparison with experiment point to a high sensitivity of this reaction with respect to small details, particularly in the description of the Li{sup +} core.

  5. Ionization Potential Depression in Strongly Coupled Plasmas

    NASA Astrophysics Data System (ADS)

    Wark, Justin; Ciricosta, Orlando; Vinko, Sam; Crowley, Basil

    2013-10-01

    The focusing of the output of 4th generation femtosecond X-ray sources to ultra-high intensities has enabled the creation of hot (close to 200-eV) aluminum plasmas at exactly solid density. Tuning of the X-ray FEL energy that produces the plasma, and observation of the subsequent K- α fluorescence from the highly charged ions allows direct measurements of the K-edges, and hence ionization potential depression (IPD). The results of these experiments show far higher depressions than those predicted by the frequently-used Stewart-Pyatt model, but appear to be in contradiction with laser-plasma experimental data at similar densities, but with hotter, less strongly-coupled plasmas. We present here new calculations of the IPD, both ab initio and analytic, and discuss the relevance of the coupling parameter to the IPD. We further explore what constitutes our understanding of the physics of IPD, and how it should be modelled.

  6. Strong quantum scarring by local impurities

    PubMed Central

    Luukko, Perttu J. J.; Drury, Byron; Klales, Anna; Kaplan, Lev; Heller, Eric J.; Räsänen, Esa

    2016-01-01

    We discover and characterise strong quantum scars, or quantum eigenstates resembling classical periodic orbits, in two-dimensional quantum wells perturbed by local impurities. These scars are not explained by ordinary scar theory, which would require the existence of short, moderately unstable periodic orbits in the perturbed system. Instead, they are supported by classical resonances in the unperturbed system and the resulting quantum near-degeneracy. Even in the case of a large number of randomly scattered impurities, the scars prefer distinct orientations that extremise the overlap with the impurities. We demonstrate that these preferred orientations can be used for highly efficient transport of quantum wave packets across the perturbed potential landscape. Assisted by the scars, wave-packet recurrences are significantly stronger than in the unperturbed system. Together with the controllability of the preferred orientations, this property may be very useful for quantum transport applications. PMID:27892510

  7. Designing asymmetric multiferroics with strong magnetoelectric coupling

    NASA Astrophysics Data System (ADS)

    Lu, Xuezeng; Xiang, Hongjun; Rondinelli, James; Materials Theory; Design Group Team

    2015-03-01

    Multiferroics offer exciting opportunities for electric-field control of magnetism. Single-phase multiferroics suitable for such applications at room temperature need much more study. Here, we propose the concept of an alternative type of multiferroics, namely, the ``asymmetric multiferroic.'' In asymmetric multiferroics, two locally stable ferroelectric states are not symmetrically equivalent, leading to different magnetic properties between these two states. Furthermore, we predict from first principles that a Fe-Cr-Mo superlattice with the LiNbO3-type structure is such an asymmetric multiferroic. The strong ferrimagnetism, high ferroelectric polarization, and significant dependence of the magnetic transition temperature on polarization make this asymmetric multiferroic an ideal candidate for realizing electric-field control of magnetism at room temperature. Our study suggests that the asymmetric multiferroic may provide an alternative playground for voltage control of magnetism and find its applications in spintronics and quantum computing.

  8. Designing asymmetric multiferroics with strong magnetoelectric coupling

    NASA Astrophysics Data System (ADS)

    Lu, X. Z.; Xiang, H. J.

    2014-09-01

    Multiferroics offer exciting opportunities for electric-field control of magnetism. Single-phase multiferroics suitable for such applications at room temperature need much more study. Here, we propose the concept of an alternative type of multiferroics, namely, the "asymmetric multiferroic." In asymmetric multiferroics, two locally stable ferroelectric states are not symmetrically equivalent, leading to different magnetic properties between these two states. Furthermore, we predict from first principles that a Fe-Cr-Mo superlattice with the LiNbO3-type structure is such an asymmetric multiferroic. The strong ferrimagnetism, high ferroelectric polarization, and significant dependence of the magnetic transition temperature on polarization make this asymmetric multiferroic an ideal candidate for realizing electric-field control of magnetism at room temperature. Our study suggests that the asymmetric multiferroic may provide an alternative playground for voltage control of magnetism and find its applications in spintronics and quantum computing.

  9. Bound states in a strong magnetic field

    SciTech Connect

    Machado, C. S.; Navarra, F. S.; Noronha, J.; Oliveira, E. G.; Ferreira Filho, L. G.

    2013-03-25

    We expect a strong magnetic field to be produced in the perpendicular direction to the reaction plane, in a noncentral heavy-ion collision . The strength of the magnetic field is estimated to be eB{approx}m{sup 2}{sub {pi}}{approx} 0.02 GeV{sup 2} at the RHIC and eB{approx} 15m{sup 2}{sub {pi}}{approx} 0.3 GeV{sup 2} at the LHC. We investigate the effects of the magnetic field on B{sup 0} and D{sup 0} mesons, focusing on the changes of the energy levels and of the mass of the bound states.

  10. Towards Integrated Marmara Strong Motion Network

    NASA Astrophysics Data System (ADS)

    Durukal, E.; Erdik, M.; Safak, E.; Ansal, A.; Ozel, O.; Alcik, H.; Mert, A.; Kafadar, N.; Korkmaz, A.; Kurtulus, A.

    2009-04-01

    Istanbul has a 65% chance of having a magnitude 7 or above earthquake within the next 30 years. As part of the preparations for the future earthquake, strong motion networks have been installed in and around Istanbul. The Marmara Strong Motion Network, operated by the Department of Earthquake Engineering of Kandilli Observatory and Earthquake Research Institute, encompasses permanent systems outlined below. It is envisaged that the networks will be run by a single entity responsible for technical management and maintanence, as well as for data management, archiving and dissemination through dedicated web-based interfaces. • Istanbul Earthquake Rapid Response and Early Warning System - IERREWS (one hundred 18-bit accelerometers for rapid response; ten 24-bit accelerometers for early warning) • IGDAŞ Gas Shutoff Network (100 accelerometers to be installed in 2010 and integrated with IERREWS) • Structural Monitoring Arrays - Fatih Sultan Mehmet Suspension Bridge (1200m-long suspension bridge across the Bosphorus, five 3-component accelerometers + GPS sensors) - Hagia Sophia Array (1500-year-old historical edifice, 9 accelerometers) - Süleymaniye Mosque Array (450-year-old historical edifice,9 accelerometers) - Fatih Mosque Array (237-year-old historical edifice, 9 accelerometers) - Kanyon Building Array (high-rise office building, 5 accelerometers) - Isbank Tower Array (high-rise office building, 5 accelerometers) - ENRON Array (power generation facility, 4 acelerometers) - Mihrimah Sultan Mosque Array (450-year-old historical edifice,9 accelerometers + tiltmeters, to be installed in 2009) - Sultanahmet Mosque Array, (390-year-old historical edifice, 9 accelerometers + tiltmeters, to be installed in 2009) • Special Arrays - Atakoy Vertical Array (four 3-component accelerometers at 25, 50, 75, and 150 m depths) - Marmara Tube Tunnel (1400 m long submerged tunnel, 128 ch. accelerometric data, 24 ch. strain data, to be installed in 2010) - Air-Force Academy

  11. Observable properties of strong gravitational lenses

    NASA Astrophysics Data System (ADS)

    Tessore, Nicolas

    2017-01-01

    It is shown which properties of a strong gravitational lens can in principle be recovered from observations of multiple extended images when no assumptions are made about the deflector or sources. The mapping between individual multiple images is identified as the carrier of information about the gravitational lens and it is shown how this information can be extracted from a hypothetical observation. The derivatives of the image map contain information about convergence ratios and reduced shears over the regions of the multiple images. For two observed images, it is not possible to reconstruct the convergence ratio and shear at the same time. For three observed images, it is possible to recover the convergence ratios and reduced shears identically. For four or more observed images, the system of constraints is overdetermined, but the same quantities can theoretically be recovered.

  12. Strongly Acidic Auxin Indole-3-Methanesulfonic Acid

    PubMed Central

    Cohen, Jerry D.; Baldi, Bruce G.; Bialek, Krystyna

    1985-01-01

    A radiochemical synthesis is described for [14C]indole-3-methanesulfonic acid (IMS), a strongly acidic auxin analog. Techniques were developed for fractionation and purification of IMS using normal and reverse phase chromatography. In addition, the utility of both Fourier transform infrared spectrometry and fast atom bombardment mass spectrometry for analysis of IMS has been demonstrated. IMS was shown to be an active auxin, stimulating soybean hypocotyl elongation, bean first internode curvature, and ethylene production. IMS uptake by thin sections of soybean hypocotyl was essentially independent of solution pH and, when applied at a 100 micromolar concentration, IMS exhibited a basipetal polarity in its transport in both corn coleoptile and soybean hypocotyl sections. [14C]IMS should, therefore, be a useful compound to study fundamental processes related to the movement of auxins in plant tissues and organelles. PMID:16664007

  13. Strong spurious phase in teleseismic correlations

    NASA Astrophysics Data System (ADS)

    Li, Lei; Campillo, Michel; Boue, Pierre; Thomas, Christine; Roux, Philippe; Shapiro, Nikolai

    2016-04-01

    In the teleseismic correlations of continuous ambient noise data from Fnet array in Japan and Lapnet array in Finland, we observed a clear spurious phase with an apparent slowness of about 4.6 s/deg and an arrival time of about 430 s, far ahead of the P arrival at around 628 s. The spurious signal is rather strong from Fnet to Lapnet, arising from the correlating between the P wave from New Zealand arriving at Fnet and the PKP wave at Lapnet. The spurious phase in the opposite direction is weaker, with the source region locating in the low-latitude Atlantic Ocean near South America. Spurious phases near P and PcP waves are also present.

  14. Strong gravity and structure of topological solitons

    NASA Astrophysics Data System (ADS)

    Rybakov, Yu. P.

    The unification of Skyrme and Faddeev chiral models describing baryons and leptons respectively as topological solitons is suggested within the framework of 16-spinor field ψ = ψ1 ⊕ ψ2 nonlinear model containing two 8-semispinors ψ1 and ψ2. Using Brioschi identity for 8-spinors and special structure of the Higgs potential V implying the spontaneous symmetry breaking, it is possible to realize topological soliton-like excitations of two kinds due to the choice of S2- or S3- manifolds as phase spaces. The interactions with electromagnetic, Yang--Mills and gravitational fields are exhibited through the extention of derivatives via gauge invariance principle. Specific inclusion in the Higgs potential of the Kretschmann gravitational invariant K = RμνσλRμνσλ/48 permits one to obtain the strong gravity behavior at small distances and guarantee the correspondence with Quantum Mechanics at large distances.

  15. Strong acoustic coupling to a superconducting qubit

    NASA Astrophysics Data System (ADS)

    Gustafsson, Martin; Aref, Thomas; Frisk Kockum, Anton; Ekström, Maria; Johansson, Göran; Delsing, Per

    2014-03-01

    Micromechanical resonators can be used to store quantum information, as shown in several recent experiments. These resonators typically have the form of membranes or beams, and phonons are localized to their vibrational eigenmodes. We present a different kind of mechanical quantum device, where propagating phonons serve as carriers for quantum information. At the core of our device is a superconducting qubit, designed to couple to Surface Acoustic Waves (SAW) in the underlying substrate through the piezoelectric effect. This type of coupling can be very strong, and in our case exceeds the coupling to any external electromagnetic modes. The acoustic waves propagate freely on the surface of the substrate, and we use a remote electro-acoustic transducer to address the qubit acoustically and listen to its emission of phonons. This presentation focuses on the basic properties of our acoustic quantum system, and we include experimental data that demonstrate the quantized coupling between the qubit and the propagating acoustic waves.

  16. Strong mobility in weakly disordered systems

    SciTech Connect

    Ben-naim, Eli; Krapivsky, Pavel

    2009-01-01

    We study transport of interacting particles in weakly disordered media. Our one-dimensional system includes (i) disorder, the hopping rate governing the movement of a particle between two neighboring lattice sites is inhomogeneous, and (ii) hard core interaction, the maximum occupancy at each site is one particle. We find that over a substantial regime, the root-mean-square displacement of a particle s grows superdiffusively with time t, {sigma}{approx}({epsilon}t){sup 2/3}, where {epsilon} is the disorder strength. Without disorder the particle displacement is subdiffusive, {sigma} {approx}t{sup 1/4}, and therefore disorder strongly enhances particle mobility. We explain this effect using scaling arguments, and verify the theoretical predictions through numerical simulations. Also, the simulations show that regardless of disorder strength, disorder leads to stronger mobility over an intermediate time regime.

  17. Resonant Strong Field Nonlinear Optical Interactions

    NASA Astrophysics Data System (ADS)

    Coppeta, David Anthony

    This work considers the steady state nonlinear response of a medium subjected to electromagnetic fields which are resonant and/or strong. In this regime, pertubation expansions in the field amplitude(s) diverge and non-pertubative techniques are required. Two general cases are considered. In the first case, radiative renormalization is applied to Four Wave Mixing (FWM) in a four level system with three resonant driving fields. The absorption and generation of a weak FWM signal are considered. Several variants including coherent anti-Stokes Raman scattering are considered. The second case is a two level atom subject to excitation by an arbitrarily amplitude modulated field. The domain of solution is extended to non-equal damping rates with zero detuning from resonance. As an example, the steady state response to step function amplitude modulation is treated.

  18. Strongly Interacting Matter at High Energy Density

    SciTech Connect

    McLerran,L.

    2008-09-07

    This lecture concerns the properties of strongly interacting matter (which is described by Quantum Chromodynamics) at very high energy density. I review the properties of matter at high temperature, discussing the deconfinement phase transition. At high baryon density and low temperature, large N{sub c} arguments are developed which suggest that high baryonic density matter is a third form of matter, Quarkyonic Matter, that is distinct from confined hadronic matter and deconfined matter. I finally discuss the Color Glass Condensate which controls the high energy limit of QCD, and forms the low x part of a hadron wavefunction. The Glasma is introduced as matter formed by the Color Glass Condensate which eventually thermalizes into a Quark Gluon Plasma.

  19. Convex Modeling of Interactions with Strong Heredity

    PubMed Central

    Haris, Asad; Witten, Daniela; Simon, Noah

    2015-01-01

    We consider the task of fitting a regression model involving interactions among a potentially large set of covariates, in which we wish to enforce strong heredity. We propose FAMILY, a very general framework for this task. Our proposal is a generalization of several existing methods, such as VANISH [Radchenko and James, 2010], hierNet [Bien et al., 2013], the all-pairs lasso, and the lasso using only main effects. It can be formulated as the solution to a convex optimization problem, which we solve using an efficient alternating directions method of multipliers (ADMM) algorithm. This algorithm has guaranteed convergence to the global optimum, can be easily specialized to any convex penalty function of interest, and allows for a straightforward extension to the setting of generalized linear models. We derive an unbiased estimator of the degrees of freedom of FAMILY, and explore its performance in a simulation study and on an HIV sequence data set.

  20. Pairing phenomena in strongly correlated Fermi liquids

    NASA Astrophysics Data System (ADS)

    Krotscheck, E.; Smith, R. A.; Jackson, A. D.

    1981-12-01

    The correlated-basis-function method is extended to deal with pairing phenomena in strongly correlated Fermi liquids. With a variational ansatz for the model wave function we derive the "correlated" analog of the conventional Bardeen-Cooper-Schrieffer (or Balian-Werthamer), Anderson-Brinkman-Morel theory of pairing. A suitable (and well-controlled) set of approximations brings the theory into a form identical to the conventional theories, but with the bare interaction replaced by a weak effective interaction and the bare single-particle energies replaced by an effective single-particle spectrum. As usual, liquid 3He provides a very stringent test of the theory, as both the interaction and the experimental facts are pretty clear. The variational estimates for the pairing interaction are improved by nonorthogonal perturbation theory. We find the expected enhancement of the attraction in P waves, although the restriction to effective two-body interactions appears to be insufficient to generate P-wave pairing.

  1. Origin of strong dispersion in Hubbard insulators

    DOE PAGES

    Wang, Y.; Wohlfeld, K.; Moritz, B.; ...

    2015-08-10

    Using cluster perturbation theory, we explain the origin of the strongly dispersive feature found at high binding energy in the spectral function of the Hubbard model. By comparing the Hubbard and $t₋J₋3s$ model spectra, we show that this dispersion does not originate from either coupling to spin fluctuations ($∝ J$ ) or the free hopping ($∝ t$ ). Instead, it should be attributed to a long-range, correlated hopping $∝ t²/U$ which allows an effectively free motion of the hole within the same antiferromagnetic sublattice. This origin explains both the formation of the high-energy anomaly in the single-particle spectrum and themore » sensitivity of the high-binding-energy dispersion to the next-nearest-neighbor hopping $t'$ .« less

  2. Origin of strong dispersion in Hubbard insulators

    SciTech Connect

    Wang, Y.; Wohlfeld, K.; Moritz, B.; Jia, C. J.; van Veenendaal, M.; Wu, K.; Chen, C. -C.; Devereaux, T. P.

    2015-08-10

    Using cluster perturbation theory, we explain the origin of the strongly dispersive feature found at high binding energy in the spectral function of the Hubbard model. By comparing the Hubbard and $t₋J₋3s$ model spectra, we show that this dispersion does not originate from either coupling to spin fluctuations ($∝ J$ ) or the free hopping ($∝ t$ ). Instead, it should be attributed to a long-range, correlated hopping $∝ t²/U$ which allows an effectively free motion of the hole within the same antiferromagnetic sublattice. This origin explains both the formation of the high-energy anomaly in the single-particle spectrum and the sensitivity of the high-binding-energy dispersion to the next-nearest-neighbor hopping $t'$ .

  3. Competition between radiative and strong force decay

    NASA Astrophysics Data System (ADS)

    Tabor, Samuel

    2017-01-01

    For nuclear states unbound to neutron decay, radiative emission is often assumed to not dominate over neutron decay mediated by the far stronger strong interaction, except for very low neutron energies and high angular momentum barriers. Recent experimental investigations of 19O and 27 Mg populated in heavy-ion fusion-evaporation reactions have revealed predominantly gamma decays from a number of states unbound to neutron decay by up to 2 MeV. In most cases the angular momentum barrier is not sufficient to inhibit neutron decay enough to allow E-M decay with widths of up to an eV or so to win. Other inhibitions to particle decay, including low spectroscopic factors, will be discussed. Supported in part by NSF Grant No. 1401574.

  4. Scaling of chaos in strongly nonlinear lattices

    SciTech Connect

    Mulansky, Mario

    2014-06-15

    Although it is now understood that chaos in complex classical systems is the foundation of thermodynamic behavior, the detailed relations between the microscopic properties of the chaotic dynamics and the macroscopic thermodynamic observations still remain mostly in the dark. In this work, we numerically analyze the probability of chaos in strongly nonlinear Hamiltonian systems and find different scaling properties depending on the nonlinear structure of the model. We argue that these different scaling laws of chaos have definite consequences for the macroscopic diffusive behavior, as chaos is the microscopic mechanism of diffusion. This is compared with previous results on chaotic diffusion [M. Mulansky and A. Pikovsky, New J. Phys. 15, 053015 (2013)], and a relation between microscopic chaos and macroscopic diffusion is established.

  5. Is It Possible to Predict Strong Earthquakes?

    NASA Astrophysics Data System (ADS)

    Polyakov, Y. S.; Ryabinin, G. V.; Solovyeva, A. B.; Timashev, S. F.

    2015-07-01

    The possibility of earthquake prediction is one of the key open questions in modern geophysics. We propose an approach based on the analysis of common short-term candidate precursors (2 weeks to 3 months prior to strong earthquake) with the subsequent processing of brain activity signals generated in specific types of rats (kept in laboratory settings) who reportedly sense an impending earthquake a few days prior to the event. We illustrate the identification of short-term precursors using the groundwater sodium-ion concentration data in the time frame from 2010 to 2014 (a major earthquake occurred on 28 February 2013) recorded at two different sites in the southeastern part of the Kamchatka Peninsula, Russia. The candidate precursors are observed as synchronized peaks in the nonstationarity factors, introduced within the flicker-noise spectroscopy framework for signal processing, for the high-frequency component of both time series. These peaks correspond to the local reorganizations of the underlying geophysical system that are believed to precede strong earthquakes. The rodent brain activity signals are selected as potential "immediate" (up to 2 weeks) deterministic precursors because of the recent scientific reports confirming that rodents sense imminent earthquakes and the population-genetic model of K irshvink (Soc Am 90, 312-323, 2000) showing how a reliable genetic seismic escape response system may have developed over the period of several hundred million years in certain animals. The use of brain activity signals, such as electroencephalograms, in contrast to conventional abnormal animal behavior observations, enables one to apply the standard "input-sensor-response" approach to determine what input signals trigger specific seismic escape brain activity responses.

  6. Strong curvature effects in Neumann wave problems

    SciTech Connect

    Willatzen, M.; Pors, A.; Gravesen, J.

    2012-08-15

    Waveguide phenomena play a major role in basic sciences and engineering. The Helmholtz equation is the governing equation for the electric field in electromagnetic wave propagation and the acoustic pressure in the study of pressure dynamics. The Schroedinger equation simplifies to the Helmholtz equation for a quantum-mechanical particle confined by infinite barriers relevant in semiconductor physics. With this in mind and the interest to tailor waveguides towards a desired spectrum and modal pattern structure in classical structures and nanostructures, it becomes increasingly important to understand the influence of curvature effects in waveguides. In this work, we demonstrate analytically strong curvature effects for the eigenvalue spectrum of the Helmholtz equation with Neumann boundary conditions in cases where the waveguide cross section is a circular sector. It is found that the linear-in-curvature contribution originates from parity symmetry breaking of eigenstates in circular-sector tori and hence vanishes in a torus with a complete circular cross section. The same strong curvature effect is not present in waveguides subject to Dirichlet boundary conditions where curvature contributions contribute to second-order in the curvature only. We demonstrate this finding by considering wave propagation in a circular-sector torus corresponding to Neumann and Dirichlet boundary conditions, respectively. Results for relative eigenfrequency shifts and modes are determined and compared with three-dimensional finite element method results. Good agreement is found between the present analytical method using a combination of differential geometry with perturbation theory and finite element results for a large range of curvature ratios.

  7. Bodrum Strong Motion Network, Mugla, Turkey

    NASA Astrophysics Data System (ADS)

    Alcik, H. A.; Tanircan, G.; Korkmaz, A.

    2015-12-01

    The Gulf of Gökova is located in southwestern Turkey near the Aegean Sea and surrounded by Datça Peninsula to the south, the island of Kos to the west and Bodrum Peninsula to the north. The Bodrum peninsula with a population of one million in summer season is one of the most populated touristic centers of Turkey. This region is also surrounded by numerous active seismic entities such as Ula-Ören Fault Zone, Gökova Graben etc.. and demonstrates high seismic hazard. In the past, many destructive earthquakes have occurred in southwestern Turkey. One of the destructive historical earthquakes is 1493 Kos event (Mw=6.9) caused heavy damage in Bodrum. In the instrumental period seismic activity in the Gökova region includes the Ms>6.0 earthquakes of 23 April 1933 (Ms=6.4), 23 May 1941 (Ms=6.0), 13 December 1941 (Ms=6.5) events. Intense earthquake activity (Mw5+) occurred in Gulf of Gökova in August 2004 and January 2005. Considering the high seismicity and population of this region, a strong ground motion monitoring system stationed in dense settlements in the Bodrum Peninsula: Bodrum, Turgutreis, Yalıkavak, Çiftlik and Ortakent was deployed on June 2015. The network consists of 5 strong motion recorders, has been set up with the aim of monitoring of regional earthquakes, collecting accurate and reliable data for engineering and scientific research purposes, in particular to provide input for future earthquake rapid reporting and early warning implementation projects on urban environments in the Bodrum peninsula and the surrounding areas. In this poster presentation, we briefly introduce the Bodrum Network and discuss our future plans for further developments.

  8. Cyclotron resonance cooling by strong laser field

    SciTech Connect

    Tagcuhi, Toshihiro; Mima, Kunioka

    1995-12-31

    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.

  9. Dynamical core polarization in strong-field ionization

    NASA Astrophysics Data System (ADS)

    Zhao, Zengxiu; Zhang, Bin; Yuan, Jianmin

    2014-05-01

    Core polarization plays an important role in both ionization and high harmonic generation processes of molecules driven by strong laser fields. With our recently developed three-dimensional time-dependent Hartree-Fock method, we investigate the orientation-dependent ionization of CO molecules. It is found that the full ionization results are in good agreement with the recent experiment. The comparisons between the full method and the single-active-orbital method show that although the core electrons are generally more tightly bound and contribute little to the total ionization yields, their dynamics cannot be ignored, which effectively modifies the behavior of electrons in the HOMO. By incorporating it into the SAO method, we identify that the dynamic core polarization plays an important role in the tunneling ionization of CO molecules, which is helpful for the future development of the tunneling ionization theory beyond the single active electron approximation. In order to further verify the role of core polarization, exact calculations are performed for the ionization of two-electron model systems by strong laser fields. The limitations of HF and the SAE are quantified and the tunneling ionization rate is shown improved with the core-polarization induced correction.

  10. Strong parallel magnetic field effects on the hydrogen molecular ion

    NASA Astrophysics Data System (ADS)

    Guan, Xiaoxu; Li, Baiwen; Taylor, K. T.

    2003-09-01

    Equilibrium distances, binding energies and dissociation energies for the ground and low-lying states of the hydrogen molecular ion in a strong magnetic field parallel to the internuclear axis are calculated and refined, by using the two-dimensional pseudospectral method. High-precision results are presented for the binding energies over a wider field regime than already given in the literature (Kravchenko and Liberman 1997 Phys. Rev. A 55 2701). The present work removes a long-standing discrepancy for the Req value in the 1sigmau state at a field strength of 1.0 × 106 T. The dissociation energies of the antibonding 1pig state induced by magnetic fields are determined accurately. We have also observed that the antibonding 1pig potential energy curve develops a minimum if the field is sufficiently strong. Some unreliable results in the literature are pointed out and discussed. A way to efficiently treat vibrational processes and coupling between the nuclear and the electronic motions in magnetic fields is also suggested within a three-dimensional pseudospectral scheme.

  11. Coherent Dynamics Following Strong Field Ionization of Polyatomic Molecules

    NASA Astrophysics Data System (ADS)

    Konar, Arkaprabha; Shu, Yinan; Lozovoy, Vadim; Jackson, James; Levine, Benjamin; Dantus, Marcos

    2015-03-01

    Molecules, as opposed to atoms, present confounding possibilities of nuclear and electronic motion upon strong field ionization. The dynamics and fragmentation patterns in response to the laser field are structure sensitive; therefore, a molecule cannot simply be treated as a ``bag of atoms'' during field induced ionization. We consider here to what extent molecules retain their molecular identity and properties under strong laser fields. Using time-of-flight mass spectrometry in conjunction with pump-probe techniques we study the dynamical behavior of these molecules, monitoring ion yield modulation caused by intramolecular motions post ionization. The delay scans show that among positional isomers the variations in relative energies, amounting to only a few hundred meVs, influence the dynamical behavior of the molecules despite their having experienced such high fields (V/Å). Ab initio calculations were performed to predict dynamics along with single and multiphoton resonances in the neutral and ionic states. We propose that single electron ionization occurs within an optical cycle with the electron carrying away essentially all of the energy, leaving behind little internal energy in the cation. Evidence for this observation comes from coherent vibrational motion governed by the potential energy surface of the ground state of the cation. Subsequent fragmentation of the cation takes place as a result of further photon absorption modulated by one- and two-photon resonances, which provide sufficient energy to overcome the dissociation energy.

  12. Numerical analysis of strongly nonlinear extensional vibrations in elastic rods.

    PubMed

    Vanhille, Christian; Campos-Pozuelo, Cleofé

    2007-01-01

    In the framework of transduction, nondestructive testing, and nonlinear acoustic characterization, this article presents the analysis of strongly nonlinear vibrations by means of an original numerical algorithm. In acoustic and transducer applications in extreme working conditions, such as the ones induced by the generation of high-power ultrasound, the analysis of nonlinear ultrasonic vibrations is fundamental. Also, the excitation and analysis of nonlinear vibrations is an emergent technique in nonlinear characterization for damage detection. A third-order evolution equation is derived and numerically solved for extensional waves in isotropic dissipative media. A nine-constant theory of elasticity for isotropic solids is constructed, and the nonlinearity parameters corresponding to extensional waves are proposed. The nonlinear differential equation is solved by using a new numerical algorithm working in the time domain. The finite-difference numerical method proposed is implicit and only requires the solution of a linear set of equations at each time step. The model allows the analysis of strongly nonlinear, one-dimensional vibrations and can be used for prediction as well as characterization. Vibration waveforms are calculated at different points, and results are compared for different excitation levels and boundary conditions. Amplitude distributions along the rod axis for every harmonic component also are evaluated. Special attention is given to the study of high-amplitude damping of vibrations by means of several simulations. Simulations are performed for amplitudes ranging from linear to nonlinear and weak shock.

  13. Capacitance and compressibility of heterostructures with strong electronic correlations

    NASA Astrophysics Data System (ADS)

    Steffen, Kevin; Frésard, Raymond; Kopp, Thilo

    2017-01-01

    Strong electronic correlations related to a repulsive local interaction suppress the electronic compressibility in a single-band model, and the capacitance of a corresponding metallic film is directly related to its electronic compressibility. Both statements may be altered significantly when two extensions to the system are implemented which we investigate here: (i) we introduce an attractive nearest-neighbor interaction V as antagonist to the repulsive onsite repulsion U , and (ii) we consider nanostructured multilayers (heterostructures) assembled from two-dimensional layers of these systems. We determine the respective total compressibility κ and capacitance C of the heterostructures within a strong coupling evaluation, which builds on a Kotliar-Ruckenstein slave-boson technique. Whereas the capacitance C (n ) for electronic densities n close to half-filling is suppressed, illustrated by a correlation induced dip in C (n ) , it may be appreciably enhanced close to a van Hove singularity. Moreover, we show that the capacitance may be a nonmonotonic function of U close to half-filling for both attractive and repulsive V . The compressibility κ can differ from C substantially, as κ is very sensitive to internal electrostatic energies which in turn depend on the specific setup of the heterostructure. In particular, we show that a capacitor with a polar dielectric has a smaller electronic compressibility and is more stable against phase separation than a standard nonpolar capacitor with the same capacitance.

  14. HR 7355 - another rapidly braking He-strong CP star?

    NASA Astrophysics Data System (ADS)

    Mikulášek, Z.; Krtička, J.; Henry, G. W.; de Villiers, S. N.; Paunzen, E.; Zejda, M.

    2010-02-01

    Context. Strong meridional mixing induced by rapid rotation is one reason why all hot main-sequence stars are not chemically peculiar. However, the finding that the He-strong CP star HR 7355 is a rapid rotator complicates this concept. Aims: Our goal is to explain the observed behaviour of HR 7355 based on period analysis of all available photometry. Methods: Over two years, we acquired 114 new BV observations of HR 7355 at observatories in Arizona, U.S.A and Cape Town, South Africa. We performed period analyses of the new observations along with new analyses of 732 archival measurements from the Hipparcos and ASAS projects. Results: We find that the light curves of HR 7355gt; in various filters are quite similar, with amplitudes 0.035(4), 0.036(4), and 0.038(3) mag in B, Hp, and V, respectively. The light curves are double-peaked, with unevenly deep minima. We substantially refine the rotational period to be P = 0.5214410(4)d, indicating that HR 7355gt; is the most rapidly rotating CP star known. Our period analyses reveal a possible lengthening of the rotational period with dot{P}/P = 2.4(8)×10-6 yr-1. Conclusions: We conclude that the shape and amplitude of HR 7355gt; light curves are typical of magnetic He-strong CP stars, for which light variations are the result of photospheric spots on the surface of a rotating star. We hypothesise that the light variations are caused mainly by an uneven distribution of overabundant helium on the star's surface. We briefly describe and discuss the cause of the rapid rotational braking of the star. Photometric data are only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/511/L7

  15. Studies of strong Langmuir turbulence effects at HAARP

    NASA Astrophysics Data System (ADS)

    Sheerin, J. P.; Oyama, S. I.; Watkins, B. J.; Bristow, W. A.

    2006-10-01

    High power HF transmitters induce a number of plasma instabilities in the interaction region of overdense ionospheric plasma. Radars such as SuperDARN have been used to study artificial field-aligned irregularities (AFAI) created by the high power HF radiowave at the HAARP Ionospheric Observatory, Gakona, AK. A new Modular UHF Ionospheric Radar (MUIR) sited at HAARP may now be used to monitor changes in the Langmuir plasma waves detected in the UHF backscatter. We report the results from recent campaigns using these new facilities in coordinated and comprehensive studies of strong Langmuir turbulence (SLT). Among the effects observed and studied are: SLT spectra including the outshifted plasma line or `free-mode', appearance of a short timescale ponderomotive overshoot effect, temporal evolution of SLT, dependence of SLT on growth or suppression of AFAI, dependence of AFAI and MUIR backscatter on HAARP pulselength and duty-cycle, aspect angle dependence of the intensity of the plasma line. In particular, we explore the observed `magnetic-zenith' effect of increased turbulence with the HF wave directed up the field line. Langmuir modes parallel to the geomagnetic field are proposed to explain other features in stimulated electromagnetic emissions (SEE). These plasma waves are theorized to play a key role in certain features of radio-induced aurora. Experimental results are then compared to predictions from recent modeling efforts.

  16. Neutron Limit on the Strongly-Coupled Chameleon Field

    NASA Astrophysics Data System (ADS)

    Pushin, Dmitry

    2016-03-01

    One of the major open questions of cosmology is the physical origin of the dark energy. There are a few sets of theories which might explain this origin that could be tested experimentally. The chameleon dark energy theory postulates self-interacting scalar field that couples to matter. This coupling induces a screening mechanism chosen so that the field amplitude is nonzero in empty space but is greatly suppressed in regions of terrestrial matter density. On behalf of the INDEX collaboration, I will report the most stringent upper bound on the free neutron-chameleon coupling in the strongly-coupled limit of the chameleon theory using neutron interferometric techniques. In our experiment we measure neutron phase induced by chameleon field. We report a 95 % confidence level upper bound on the neutron-chameleon coupling ranging from β < 4 . 7 ×106 for a Ratra-Peebles index of n = 1 in the nonlinear scalar field potential to β < 2 . 4 ×107 for n = 6 , one order of magnitude more sensitive than the most recent free neutron limit for intermediate n. This work was supported by NIST; NSF Grants: PHY-1205342, PHY-1068712, PHY-1307426; DOE award DE-FG02-97ER41042; NSERC CREATE and DISCOVERY programs; CERC; IUCSS and IU FRS program.

  17. A strong integrated strength and toughness artificial nacre based on dopamine cross-linked graphene oxide.

    PubMed

    Cui, Wei; Li, Mingzhu; Liu, Jiyang; Wang, Ben; Zhang, Chuck; Jiang, Lei; Cheng, Qunfeng

    2014-09-23

    Demands of the strong integrated materials have substantially increased across various industries. Inspired by the relationship of excellent integration of mechanical properties and hierarchical nano/microscale structure of the natural nacre, we have developed a strategy for fabricating the strong integrated artificial nacre based on graphene oxide (GO) sheets by dopamine cross-linking via evaporation-induced assembly process. The tensile strength and toughness simultaneously show 1.5 and 2 times higher than that of natural nacre. Meanwhile, the artificial nacre shows high electrical conductivity. This type of strong integrated artificial nacre has great potential applications in aerospace, flexible supercapacitor electrodes, artificial muscle, and tissue engineering.

  18. Effects of Strong Static Magnetic Fields on Amphibian Development and Gene Expression

    NASA Astrophysics Data System (ADS)

    Kawakami, Satomi; Kashiwagi, Keiko; Furuno, Nobuaki; Yamashita, Masamichi; Kashiwagi, Akihiko; Tanimoto, Yoshifumi

    2006-07-01

    This investigation attempts to clarify the effects of strong vertical and static magnetic fields (SMFs) of 11-15 T on Xenopus laevis development and on Xotx2 (an important regulator of fore- and midbrain morphogenesis) and Xag1 (essential for cement gland formation) gene expression. Results showed that (1) a strong SMF significantly retarded normal development and induced microcephaly, two heads, abnormal cement glands and multiple malformations, indicating that SMF inhibits normal embryonic development, (2) a strong SMF suppressed Xotx2 and Xag1 expression.

  19. Artifact associated with the use of strong iodine solution (Lugol's) in cone biopsies.

    PubMed

    Benda, J A; Lamoreaux, J; Johnson, S R

    1987-05-01

    The preoperative application of strong iodine solution (USP), commonly referred to as Lugol's solution, induces a histologic artifact in epithelial cells of cone biopsy material, most pronounced in dysplastic cells. Cellular shrinkage, cytoplasmic eosinophilia and vacuolization, development of visible intercellular space, and nuclear pyknosis with loss of chromatin detail are the major findings. Since the use of strong iodine solution (USP) is a common practice for delineating the ectocervical extent of disease prior to cone biopsy, the pathologist should recognize the artifact since its presence can make histologic interpretation difficult. Because the artifact may lead to interpretation error, alternatives to strong iodine solution (USP) should be considered.

  20. Coulomb Bound States of Strongly Interacting Photons

    NASA Astrophysics Data System (ADS)

    Maghrebi, M. F.; Gullans, M. J.; Bienias, P.; Choi, S.; Martin, I.; Firstenberg, O.; Lukin, M. D.; Büchler, H. P.; Gorshkov, A. V.

    2015-09-01

    We show that two photons coupled to Rydberg states via electromagnetically induced transparency can interact via an effective Coulomb potential. This interaction gives rise to a continuum of two-body bound states. Within the continuum, metastable bound states are distinguished in analogy with quasibound states tunneling through a potential barrier. We find multiple branches of metastable bound states whose energy spectrum is governed by the Coulomb potential, thus obtaining a photonic analogue of the hydrogen atom. Under certain conditions, the wave function resembles that of a diatomic molecule in which the two polaritons are separated by a finite "bond length." These states propagate with a negative group velocity in the medium, allowing for a simple preparation and detection scheme, before they slowly decay to pairs of bound Rydberg atoms.

  1. An IPTG Inducible Conditional Expression System for Mycobacteria

    PubMed Central

    Ravishankar, Sudha; Ambady, Anisha; Ramu, Haripriya; Mudugal, Naina Vinay; Tunduguru, Ragadeepthi; Anbarasu, Anand; Sharma, Umender K.; Sambandamurthy, Vasan K.; Ramaiah, Sudha

    2015-01-01

    Conditional expression strains serve as a valuable tool to study the essentiality and to establish the vulnerability of a target under investigation in a drug discovery program. While essentiality implies an absolute requirement of a target function, vulnerability provides valuable information on the extent to which a target function needs to be depleted to achieve bacterial growth inhibition followed by cell death. The critical feature of an ideal conditional expression system is its ability to tightly regulate gene expression to achieve the full spectrum spanning from a high level of expression in order to support growth and near zero level of expression to mimic conditions of gene knockout. A number of bacterial conditional expression systems have been reported for use in mycobacteria. The utility of an isopropylthiogalactoside (IPTG) inducible system in mycobacteria has been reported for protein overexpression and anti-sense gene expression from a replicating multi-copy plasmid. Herein, we report the development of a versatile set of non-replicating IPTG inducible vectors for mycobacteria which can be used for generation of conditional expression strains through homologous recombination. The role of a single lac operator versus a double lac operator to regulate gene expression was evaluated by monitoring the expression levels of β-galactosidase in Mycobacterium smegmatis. These studies indicated a significant level of leaky expression from the vector with a single lac operator but none from the vector with double lac operator. The significance of the double lac operator vector for target validation was established by monitoring the growth kinetics of an inhA, a rpoB and a ftsZ conditional expression strain grown in the presence of different concentrations of IPTG. The utility of this inducible system in identifying target specific inhibitors was established by screening a focussed library of small molecules using an inhA and a rpoB conditional expression

  2. Momentum transport in strongly coupled anisotropic plasmas in the presence of strong magnetic fields

    NASA Astrophysics Data System (ADS)

    Finazzo, Stefano Ivo; Critelli, Renato; Rougemont, Romulo; Noronha, Jorge

    2016-09-01

    We present a holographic perspective on momentum transport in strongly coupled, anisotropic non-Abelian plasmas in the presence of strong magnetic fields. We compute the anisotropic heavy quark drag forces and Langevin diffusion coefficients and also the anisotropic shear viscosities for two different holographic models, namely, a top-down deformation of strongly coupled N =4 super-Yang-Mills theory triggered by an external Abelian magnetic field, and a bottom-up Einstein-Maxwell-dilaton (EMD) model which is able to provide a quantitative description of lattice QCD thermodynamics with (2 +1 ) flavors at both zero and nonzero magnetic fields. We find that, in general, energy loss and momentum diffusion through strongly coupled anisotropic plasmas are enhanced by a magnetic field being larger in transverse directions than in the direction parallel to the magnetic field. Moreover, the anisotropic shear viscosity coefficient is smaller in the direction of the magnetic field than in the plane perpendicular to the field, which indicates that strongly coupled anisotropic plasmas become closer to the perfect fluid limit along the magnetic field. We also present, in the context of the EMD model, holographic predictions for the entropy density and the crossover critical temperature in a wider region of the (T , B ) phase diagram that has not yet been covered by lattice simulations. Our results for the transport coefficients in the phenomenologically realistic magnetic EMD model could be readily used as inputs in numerical codes for magnetohydrodynamics.

  3. Strong Motion Seismograph Based On MEMS Accelerometer

    NASA Astrophysics Data System (ADS)

    Teng, Y.; Hu, X.

    2013-12-01

    The MEMS strong motion seismograph we developed used the modularization method to design its software and hardware.It can fit various needs in different application situation.The hardware of the instrument is composed of a MEMS accelerometer,a control processor system,a data-storage system,a wired real-time data transmission system by IP network,a wireless data transmission module by 3G broadband,a GPS calibration module and power supply system with a large-volumn lithium battery in it. Among it,the seismograph's sensor adopted a three-axis with 14-bit high resolution and digital output MEMS accelerometer.Its noise level just reach about 99μg/√Hz and ×2g to ×8g dynamically selectable full-scale.Its output data rates from 1.56Hz to 800Hz. Its maximum current consumption is merely 165μA,and the device is so small that it is available in a 3mm×3mm×1mm QFN package. Furthermore,there is access to both low pass filtered data as well as high pass filtered data,which minimizes the data analysis required for earthquake signal detection. So,the data post-processing can be simplified. Controlling process system adopts a 32-bit low power consumption embedded ARM9 processor-S3C2440 and is based on the Linux operation system.The processor's operating clock at 400MHz.The controlling system's main memory is a 64MB SDRAM with a 256MB flash-memory.Besides,an external high-capacity SD card data memory can be easily added.So the system can meet the requirements for data acquisition,data processing,data transmission,data storage,and so on. Both wired and wireless network can satisfy remote real-time monitoring, data transmission,system maintenance,status monitoring or updating software.Linux was embedded and multi-layer designed conception was used.The code, including sensor hardware driver,the data acquisition,earthquake setting out and so on,was written on medium layer.The hardware driver consist of IIC-Bus interface driver, IO driver and asynchronous notification driver. The

  4. Electronic properties of strongly correlated layered oxides

    NASA Astrophysics Data System (ADS)

    Lee, Wei-Cheng

    The two-dimensional electronic systems (2DESs) have kept surprising physicists for the last few decades. Examples include the integer and fractional quantum Hall effects, cuprate superconductivity, and graphene. This thesis is intended to develop suitable theoretical tools which can be generalized to study new types of 2DESs with strong correlation feature. The first part of this thesis describes the investigation of heterostructures made by Mott insulators. This work is mostly motivated by the significant improvement of techniques for layer-by-layer growth of transition metal oxides in the last few years. We construct a toy model based on generalized Hubbard model complemented with long-ranged Coulomb interaction, and we study it by Hartree-Fock theory, dynamical mean-field theory, and Thomas-Fermi theory. We argue that interesting 2D strongly correlated electronic systems can be created in such heterostructures under several conditions. Since these 2D systems are formed entirely due to the gap generated by electron-electron interaction, they are not addiabatically connected to a noninteracting electron states. This feature makes these 2D systems distinguish from the ones created in semiconductor heterostructures, and they may be potential systems having non-Fermi liquid behaviors. The second part of this thesis is devoted to the study of collective excitations in high-temperature superconductors. One important achievement in this work is to develop a time-dependent mean-field theory for t -- U -- J -- V model, an effective low energy model for cuprates. The time-dependent mean-field theory is proven to be identical to the generalized random-phase approximation (GRPA) which includes both the bubble and ladder diagrams. We propose that the famous 41 meV magnetic resonance mode observed in the inelastic neutron scattering measurements is a collective mode arising from a conjugation relation, which has been overlooked in previous work, between the antiferromagnetic

  5. Developing Strong Geoscience Programs and Departments

    NASA Astrophysics Data System (ADS)

    MacDonald, R.; Manduca, C. A.

    2002-12-01

    Strong geoscience programs are essential for preparing future geoscientists and developing a broad public understanding of our science. Faculty working as a department team can create stronger programs than individual faculty working alone. Workshops sponsored by Project Kaleidoscope (www.pkal.org) on departmental planning in the geosciences have emphasized the importance of designing programs in the context of both departmental and student goals. Well-articulated goals form a foundation for designing curriculum, courses, and other departmental activities. Course/skill matrices have emerged as particularly valuable tools for analyzing how individual courses combine in a curriculum to meet learning goals. Integrated programs where students have opportunities to learn and use skills in multiple contexts have been developed at several institutions. Departments are leveraging synergies between courses to more effectively reach departmental goals and capitalize on opportunities in the larger campus environment. A full departmental program extends beyond courses and curriculum. Studies in physics (National Task Force on Undergraduate Physics, Hilborne, 2002) indicate the importance of activities such as recruiting able students, mentoring students, providing courses appropriate for pre-service K-12 teachers, assisting with professional development for a diversity of careers, providing opportunities for undergraduates to participate in research, and making connections with the local industries and businesses that employ graduates. PKAL workshop participants have articulated a wide variety of approaches to undergraduate research opportunities within and outside of class based on their departmental goals, faculty goals, and resources. Similarly, departments have a wide variety of strategies for developing productive synergies with campus-wide programs including those emphasizing writing skills, quantitative skills, and environmental studies. Mentoring and advising

  6. Arabidopsis Mutant bik1 Exhibits Strong Resistance to Plasmodiophora brassicae

    PubMed Central

    Chen, Tao; Bi, Kai; He, Zhangchao; Gao, Zhixiao; Zhao, Ying; Fu, Yanping; Cheng, Jiasen; Xie, Jiatao; Jiang, Daohong

    2016-01-01

    Botrytis-induced kinase1 (BIK1), a receptor-like cytoplasmic kinase, plays an important role in resistance against pathogens and insects in Arabidopsis thaliana. However, it remains unknown whether BIK1 functions against Plasmodiophora brassicae, an obligate biotrophic protist that attacks cruciferous plants and induces gall formation on roots. Here, we investigated the potential roles of receptors FLS2, BAK1, and BIK1 in the infection of P. brassicae cruciferous plants. Wild-type plants, fls2, and bak1 mutants showed typical symptom on roots, and the galls were filled with large quantities of resting spores, while bik1 mutant plants exhibited strong resistance to P. brassicae. Compared with that of the wild-type plants, the root hair and cortical infection rate of bik1 mutant were significantly reduced by about 40–50%. A considerable portion of bik1 roots failed to form typical galls. Even if some small galls were formed, they were filled with multinucleate secondary plasmodia. The bik1 plants accumulated less reactive oxygen species (ROS) at infected roots than other mutants and wild-type plants. Exogenous salicylic acid (SA) treatment alleviated the clubroot symptoms in wild-type plants, and the expression of the SA signaling marker gene PR1 was significantly increased in bik1. Both sid2 (salicylic acid induction-deficient 2) and npr1-1 [non-expresser of PR genes that regulate systemic acquired resistance (SAR)] mutants showed increased susceptibility to P. brassicae compared with wild-type plants. These results suggest that the resistance of bik1 to P. brassicae is possibly mediated by SA inducible mechanisms. PMID:27679580

  7. Strong liquid-crystalline polymeric compositions

    DOEpatents

    Dowell, F.

    1993-12-07

    Strong liquid-crystalline polymeric (LCP) compositions of matter are described. LCP backbones are combined with liquid crystalline (LC) side chains in a manner which maximizes molecular ordering through interdigitation of the side chains, thereby yielding materials which are predicted to have superior mechanical properties over existing LCPs. The theoretical design of LCPs having such characteristics includes consideration of the spacing distance between side chains along the backbone, the need for rigid sections in the backbone and in the side chains, the degree of polymerization, the length of the side chains, the regularity of the spacing of the side chains along the backbone, the interdigitation of side chains in sub-molecular strips, the packing of the side chains on one or two sides of the backbone to which they are attached, the symmetry of the side chains, the points of attachment of the side chains to the backbone, the flexibility and size of the chemical group connecting each side chain to the backbone, the effect of semiflexible sections in the backbone and the side chains, and the choice of types of dipolar and/or hydrogen bonding forces in the backbones and the side chains for easy alignment. 27 figures.

  8. Strong liquid-crystalline polymeric compositions

    DOEpatents

    Dowell, Flonnie

    1993-01-01

    Strong liquid-crystalline polymeric (LCP) compositions of matter. LCP backbones are combined with liquid crystalline (LC) side chains in a manner which maximizes molecular ordering through interdigitation of the side chains, thereby yielding materials which are predicted to have superior mechanical properties over existing LCPs. The theoretical design of LCPs having such characteristics includes consideration of the spacing distance between side chains along the backbone, the need for rigid sections in the backbone and in the side chains, the degree of polymerization, the length of the side chains, the regularity of the spacing of the side chains along the backbone, the interdigitation of side chains in sub-molecular strips, the packing of the side chains on one or two sides of the backbone to which they are attached, the symmetry of the side chains, the points of attachment of the side chains to the backbone, the flexibility and size of the chemical group connecting each side chain to the backbone, the effect of semiflexible sections in the backbone and the side chains, and the choice of types of dipolar and/or hydrogen bonding forces in the backbones and the side chains for easy alignment.

  9. Strong washout approximation to resonant leptogenesis

    NASA Astrophysics Data System (ADS)

    Garbrecht, Björn; Gautier, Florian; Klaric, Juraj

    2014-09-01

    We show that the effective decay asymmetry for resonant Leptogenesis in the strong washout regime with two sterile neutrinos and a single active flavour can in wide regions of parameter space be approximated by its late-time limit ɛ=Xsin(2varphi)/(X2+sin2varphi), where X=8πΔ/(|Y1|2+|Y2|2), Δ=4(M1-M2)/(M1+M2), varphi=arg(Y2/Y1), and M1,2, Y1,2 are the masses and Yukawa couplings of the sterile neutrinos. This approximation in particular extends to parametric regions where |Y1,2|2gg Δ, i.e. where the width dominates the mass splitting. We generalise the formula for the effective decay asymmetry to the case of several flavours of active leptons and demonstrate how this quantity can be used to calculate the lepton asymmetry for phenomenological scenarios that are in agreement with the observed neutrino oscillations. We establish analytic criteria for the validity of the late-time approximation for the decay asymmetry and compare these with numerical results that are obtained by solving for the mixing and the oscillations of the sterile neutrinos. For phenomenologically viable models with two sterile neutrinos, we find that the flavoured effective late-time decay asymmetry can be applied throughout parameter space.

  10. Observed strong currents under global tropical cyclones

    NASA Astrophysics Data System (ADS)

    Chang, Yu-Chia; Tseng, Ruo-Shan; Chu, Peter C.; Chen, Jau-Ming; Centurioni, Luca R.

    2016-07-01

    Global data from drifters of the Surface Velocity Program (Niiler, 2001) and tropical cyclones (TCs) from the Joint Typhoon Warning Center and National Hurricane Center were analyzed to demonstrate strong ocean currents and their characteristics under various storm intensities in the Northern Hemisphere (NH) and in the Southern Hemisphere (SH). Mean TC's translation speed (Uh) is faster in the NH (~ 4.7 m s- 1) than in the SH (~ 4.0 m s- 1), owing to the fact that TCs are more intense in the NH than in the SH. The rightward (leftward) bias of ocean mixed-layer (OML) velocity occurs in the NH (SH). As a result of this slower Uh and thus a smaller Froude number in the SH, the flow patterns in the SH under the same intensity levels of TCs are more symmetric relative to the TC center and the OML velocities are stronger. This study provides the first characterization of the near-surface OML velocity response to all recorded TCs in the SH from direct velocity measurements.

  11. Strong thin membrane structure. [solar sails

    NASA Technical Reports Server (NTRS)

    Frazer, R. E. (Inventor)

    1979-01-01

    A continuous process is described for producing strong lightweight structures for use as solar sails for spacecraft propulsion by radiation pressure. A thin reflective coating, such as aluminum, is applied to a rotating cylinder. A nylon mesh, applied over the aluminum coating, is then coated with a polymerizing material such as a para-xylylene monomer gas to polymerize as a film bound to the mesh and the aluminum. An emissivity increasing material such as chromium or silicon monoxide is applied to the polymer film to disperse such material colloidally into the growing polymer film, or to the final polymer film. The resulting membrane structure is then removed from the cylinder. Alternately, the membrane structure can be formed by etching a substrate in the form of an organic film such as a polymide, or a metal foil, to remove material from the substrate and reduce its thickness. A thin reflective coating (aluminum) is applied on one side of the substrate, and an emissivity increasing coating is applied on the reverse side of the substrate.

  12. Binary Polymer Brushes of Strongly Immiscible Polymers.

    PubMed

    Chu, Elza; Babar, Tashnia; Bruist, Michael F; Sidorenko, Alexander

    2015-06-17

    The phenomenon of microphase separation is an example of self-assembly in soft matter and has been observed in block copolymers (BCPs) and similar materials (i.e., supramolecular assemblies (SMAs) and homo/block copolymer blends (HBCs)). In this study, we use microphase separation to construct responsive polymer brushes that collapse to generate periodic surfaces. This is achieved by a chemical reaction between the minor block (10%, poly(4-vinylpyridine)) of the block copolymer and a substrate. The major block of polystyrene (PS) forms mosaic-like arrays of grafted patches that are 10-20 nm in size. Depending on the nature of the assembly (SMA, HBC, or neat BCP) and annealing method (exposure to vapors of different solvents or heating above the glass transition temperature), a range of "mosaic" brushes with different parameters can be obtained. Successive grafting of a secondary polymer (polyacrylamide, PAAm) results in the fabrication of binary polymer brushes (BPBs). Upon being exposed to specific selective solvents, BPBs may adopt different conformations. The surface tension and adhesion of the binary brush are governed by the polymer occupying the top stratum. The "mosaic" brush approach allows for a combination of strongly immiscible polymers in one brush. This facilitates substantial contrast in the surface properties upon switching, previously only possible for substrates composed of predetermined nanostructures. We also demonstrate a possible application of such PS/PAAm brushes in a tunable bioadhesion-bioadhesive (PS on top) or nonbioadhesive (PAAm on top) surface as revealed by Escherichia coli bacterial seeding.

  13. Simulating strongly coupled plasmas at low temperatures

    NASA Astrophysics Data System (ADS)

    Bussmann, M.; Schramm, U.; Habs, D.

    2006-10-01

    Realistic molecular dynamics (MD) simulations of the particle dynamics in strongly coupled plasmas require the computation of the mutual Coulomb-force for each pair of charged particles if a correct treatment of long range correlations is required. For plasmas with N > 104 particles this requires a tremendous number of computational steps which can only be addressed using efficient parallel algorithms adopted to modern super-computers. We present a new versatile MD simulation code which can simulate the non-relativistic mutual Coulomb-interaction of a large number of charged particles in arbitrary external field configurations. A demanding application is the simulation of the complete dynamics of in-trap stopping of highly charged ions in a laser cooled plasma of N = 105 24Mg+ ions. We demonstrate that the simulation is capable of delivering results on stopping times and plasma dynamics under realistic conditions. The results suggest that this stopping scheme can compete with in-trap electron cooling and might be an alternative approach for delivering ultra cold highly charged ions for future trap-based experiments aiming for precision mass measurements of stable and radioactive nuclei.

  14. Emergent behavior in strongly correlated electron systems

    NASA Astrophysics Data System (ADS)

    Pines, David

    2016-09-01

    I describe early work on strongly correlated electron systems (SCES) from the perspective of a theoretical physicist who, while a participant in their reductionist top-down beginnings, is now part of the paradigm change to a bottom-up ‘emergent’ approach with its focus on using phenomenology to find the organizing principles responsible for their emergent behavior disclosed by experiment—and only then constructing microscopic models that incorporate these. After considering the organizing principles responsible for the emergence of plasmons, quasiparticles, and conventional superconductivity in SCES, I consider their application to three of SCES’s sister systems, the helium liquids, nuclei, and the nuclear matter found in neutron stars. I note some recent applications of the random phase approximation and examine briefly the role that paradigm change is playing in two central problems in our field: understanding the emergence and subsequent behavior of heavy electrons in Kondo lattice materials; and finding the mechanism for the unconventional superconductivity found in heavy electron, organic, cuprate, and iron-based materials.

  15. Emergent behavior in strongly correlated electron systems.

    PubMed

    Pines, David

    2016-09-01

    I describe early work on strongly correlated electron systems (SCES) from the perspective of a theoretical physicist who, while a participant in their reductionist top-down beginnings, is now part of the paradigm change to a bottom-up 'emergent' approach with its focus on using phenomenology to find the organizing principles responsible for their emergent behavior disclosed by experiment-and only then constructing microscopic models that incorporate these. After considering the organizing principles responsible for the emergence of plasmons, quasiparticles, and conventional superconductivity in SCES, I consider their application to three of SCES's sister systems, the helium liquids, nuclei, and the nuclear matter found in neutron stars. I note some recent applications of the random phase approximation and examine briefly the role that paradigm change is playing in two central problems in our field: understanding the emergence and subsequent behavior of heavy electrons in Kondo lattice materials; and finding the mechanism for the unconventional superconductivity found in heavy electron, organic, cuprate, and iron-based materials.

  16. Thermal infrared anomalies of several strong earthquakes.

    PubMed

    Wei, Congxin; Zhang, Yuansheng; Guo, Xiao; Hui, Shaoxing; Qin, Manzhong; Zhang, Ying

    2013-01-01

    In the history of earthquake thermal infrared research, it is undeniable that before and after strong earthquakes there are significant thermal infrared anomalies which have been interpreted as preseismic precursor in earthquake prediction and forecasting. In this paper, we studied the characteristics of thermal radiation observed before and after the 8 great earthquakes with magnitude up to Ms7.0 by using the satellite infrared remote sensing information. We used new types of data and method to extract the useful anomaly information. Based on the analyses of 8 earthquakes, we got the results as follows. (1) There are significant thermal radiation anomalies before and after earthquakes for all cases. The overall performance of anomalies includes two main stages: expanding first and narrowing later. We easily extracted and identified such seismic anomalies by method of "time-frequency relative power spectrum." (2) There exist evident and different characteristic periods and magnitudes of thermal abnormal radiation for each case. (3) Thermal radiation anomalies are closely related to the geological structure. (4) Thermal radiation has obvious characteristics in abnormal duration, range, and morphology. In summary, we should be sure that earthquake thermal infrared anomalies as useful earthquake precursor can be used in earthquake prediction and forecasting.

  17. Internal bremsstrahlung of strongly interacting charged particles

    NASA Astrophysics Data System (ADS)

    Kurgalin, S. D.; Tchuvil'sky, Yu. M.; Churakova, T. A.

    2016-11-01

    A universal theoretical model intended for calculating internal-bremsstrahlung spectra is proposed. In this model, which can be applied to describing nuclear decays of various type (such as alpha decay, cluster decay, and proton emission), use is made of realistic nucleus-nucleus potentials. Theoretical internal-bremsstrahlung spectra were obtained for the alpha decay of the 214Po nucleus, as well as for the decay of the 222Ra nucleus via the emission of a 14C cluster and for the decay of the 113Cs nucleus via proton emission, and the properties of these spectra were studied. The contributions of various regions (internal, subbarrier, and external) to the internal-bremsstrahlung amplitude were analyzed in detail. It is shown that the contribution of the internal region to the amplitude for internal bremsstrahlung generated in nuclear decay via proton emission is quite large, but that this is not so for alpha decay and decay via cluster emission. Thus, a process in which strong interaction of nuclear particles affects the internal-bremsstrahlung spectrum if found.

  18. Strong-Field THz Interactions with Wavepackets

    NASA Astrophysics Data System (ADS)

    Bucksbaum, Philip H.

    1998-03-01

    Intense THz radiation from photoconducting antennas are particularly useful for manipulating the structure and dynamics of atomic and molecular Rydberg states. We have used sub-picosecond ``half-cycle'' field pulses to follow both the radial(C. Raman, C.W.S. Conover, C.I. Sukenik, and P. H. Bucksbaum, Physical Review Letters 76), 2436 (1996). and angular motion(C.S. Raman, T.C. Weinacht, and P.H. Bucksbaum, Physical Review A 55), R3995-8 (1997). of wavepackets. The impulse imparted to an atomic electron by these pulses can also be used to produce or alter wavepacket motion. The THz radiation can be shaped by modulating optical radiation which photo-excites the antenna.(A. S. Weling et al., Appl. Phys. Lett. 64), 137, 1994. In this way we have produced intense tunable narrow-band THz radiation, which was employed to study population transfer in strongly driven Rydberg systems.(C. Raman, M. F. DeCamp and P. H. Bucksbaum, Optics Express 1) 186 (1997). The same techniques is used to arbitrarily adjust the intensity envelope of the THz pulse, alter its central frequency over a wide range, and to produce and control dispersion. When combined with active pulse-shaping and adaptive feedback techniques, wavepacket shapes and dispersion properties can be controlled.

  19. Estimating strong correlations in optical lattices

    NASA Astrophysics Data System (ADS)

    Gertis, J.; Friesdorf, M.; Riofrío, C. A.; Eisert, J.

    2016-11-01

    Ultracold atoms in optical lattices provide one of the most promising platforms for analog quantum simulations of complex quantum many-body systems. Large-size systems can now routinely be reached and are already used to probe a large variety of different physical situations, ranging from quantum phase transitions to artificial gauge theories. At the same time, measurement techniques are still limited and full tomography for these systems seems out of reach. Motivated by this observation, we present a method to directly detect and quantify to what extent a quantum state deviates from a local Gaussian description, based on available noise correlation measurements from in situ and time-of-flight measurements. This is an indicator of the significance of strong correlations in ground and thermal states, as Gaussian states are precisely the ground and thermal states of noninteracting models. We connect our findings, augmented by numerical tensor network simulations, to notions of equilibration, disordered systems, and the suppression of transport in Anderson insulators.

  20. Where are all the Strongly Shocked Meteorites?

    NASA Astrophysics Data System (ADS)

    de Carli, P. S.; Xie, Z.; Sharp, T. G.

    2008-12-01

    Recent studies of high pressure minerals in melt veins have shown that the S6 shock stage, designating the most strongly shocked chondriticmeteorites, corresponds to a peak shock pressure of about 25 GPa and an effective shock pressure duration of the order of one second. (Sharp and De Carli 2006) Calculations of the probability distribution of asteroid-asteroid impact velocities in the early solar system indicate a broad peak over the range of 2-7 km/s with a mean of 5.29 km/s. (Bottke et al 1994) The peak pressure at the point of impact between two bodies of chondritic composition would be about 25 GPa for a 2 km/s impact. For a 7 km/s impact, the peak pressure would be about 100 GPa. We would therefore expect to find a substantial population of meteorites showing evidence of having been shocked to pressures over the range between 25 and 100 GPa. In fact, there are very few chondrites that appear to have been shocked to pressures above 25 GPa. Here we present the results of Autodyn (TM) hydrocode calculations of asteroid-asteroid impacts over the velocity range of 2-7 km/s to provide a measure of the range of expected shock effects in meteorites

  1. Tolman wormholes violate the strong energy condition

    SciTech Connect

    Hochberg, D.; Molina-Paris, C.; Visser, M.

    1999-02-01

    For an arbitrary Tolman wormhole, unconstrained by symmetry, we shall define the bounce in terms of a 3-dimensional edgeless achronal spacelike hypersurface of minimal volume (zero trace for the extrinsic curvature plus a {open_quotes}flare-out{close_quotes} condition). This enables us to severely constrain the geometry of spacetime at and near the bounce and to derive general theorems regarding violations of the energy conditions{emdash}theorems that do not involve geodesic averaging but nevertheless apply to situations much more general than the highly symmetric FRW-based subclass of Tolman wormholes. [For example, even under the mildest of hypotheses, the strong energy condition (SEC) must be violated.] Alternatively, one can dispense with the minimal volume condition and define a generic bounce entirely in terms of the motion of test particles (future-pointing timelike geodesics), by looking at the expansion of their timelike geodesic congruences. One re-confirms that the SEC must be violated at or near the bounce. In contrast, it is easy to arrange for {ital all} the other standard energy conditions to be satisfied. {copyright} {ital 1999} {ital The American Physical Society}

  2. Nanoscale electrodynamics of strongly correlated quantum materials.

    PubMed

    Liu, Mengkun; Sternbach, Aaron J; Basov, D N

    2017-01-01

    Electronic, magnetic, and structural phase inhomogeneities are ubiquitous in strongly correlated quantum materials. The characteristic length scales of the phase inhomogeneities can range from atomic to mesoscopic, depending on their microscopic origins as well as various sample dependent factors. Therefore, progress with the understanding of correlated phenomena critically depends on the experimental techniques suitable to provide appropriate spatial resolution. This requirement is difficult to meet for some of the most informative methods in condensed matter physics, including infrared and optical spectroscopy. Yet, recent developments in near-field optics and imaging enabled a detailed characterization of the electromagnetic response with a spatial resolution down to 10 nm. Thus it is now feasible to exploit at the nanoscale well-established capabilities of optical methods for characterization of electronic processes and lattice dynamics in diverse classes of correlated quantum systems. This review offers a concise description of the state-of-the-art near-field techniques applied to prototypical correlated quantum materials. We also discuss complementary microscopic and spectroscopic methods which reveal important mesoscopic dynamics of quantum materials at different energy scales.

  3. Nanoscale electrodynamics of strongly correlated quantum materials

    NASA Astrophysics Data System (ADS)

    Liu, Mengkun; Sternbach, Aaron J.; Basov, D. N.

    2017-01-01

    Electronic, magnetic, and structural phase inhomogeneities are ubiquitous in strongly correlated quantum materials. The characteristic length scales of the phase inhomogeneities can range from atomic to mesoscopic, depending on their microscopic origins as well as various sample dependent factors. Therefore, progress with the understanding of correlated phenomena critically depends on the experimental techniques suitable to provide appropriate spatial resolution. This requirement is difficult to meet for some of the most informative methods in condensed matter physics, including infrared and optical spectroscopy. Yet, recent developments in near-field optics and imaging enabled a detailed characterization of the electromagnetic response with a spatial resolution down to 10 nm. Thus it is now feasible to exploit at the nanoscale well-established capabilities of optical methods for characterization of electronic processes and lattice dynamics in diverse classes of correlated quantum systems. This review offers a concise description of the state-of-the-art near-field techniques applied to prototypical correlated quantum materials. We also discuss complementary microscopic and spectroscopic methods which reveal important mesoscopic dynamics of quantum materials at different energy scales.

  4. Strong reinforcing selection in a Texas wildflower.

    PubMed

    Hopkins, Robin; Guerrero, Rafael F; Rausher, Mark D; Kirkpatrick, Mark

    2014-09-08

    Reinforcement, the process of increased reproductive isolation due to selection against hybrids, is an important mechanism by which natural selection contributes to speciation [1]. Empirical studies suggest that reinforcement has generated reproductive isolation in many taxa (reviewed in [2-4]), and theoretical work shows it can act under broad selective conditions [5-11]. However, the strength of selection driving reinforcement has never been measured in nature. Here, we quantify the strength of reinforcing selection in the Texas wildflower Phlox drummondii using a strategy that weds a population genetic model with field data. Reinforcement in this system is caused by variation in two loci that affect flower color [12]. We quantify sharp clines in flower color where this species comes into contact with its congener, Phlox cuspidata. We develop a spatially explicit population genetic model for these clines based on the known genetics of flower color. We fit our model to the data using likelihood, and we searched parameter space using Markov chain Monte Carlo methods. We find that selection on flower color genes generated by reinforcement is exceptionally strong. Our findings demonstrate that natural selection can play a decisive role in the evolution of reproductive isolation through the process of reinforcement.

  5. Grassy Silica Nanoribbons and Strong Blue Luminescence

    NASA Astrophysics Data System (ADS)

    Wang, Shengping; Xie, Shuang; Huang, Guowei; Guo, Hongxuan; Cho, Yujin; Chen, Jun; Fujita, Daisuke; Xu, Mingsheng

    2016-09-01

    Silicon dioxide (SiO2) is one of the key materials in many modern technological applications such as in metal oxide semiconductor transistors, photovoltaic solar cells, pollution removal, and biomedicine. We report the accidental discovery of free-standing grassy silica nanoribbons directly grown on SiO2/Si platform which is commonly used for field-effect transistors fabrication without other precursor. We investigate the formation mechanism of this novel silica nanostructure that has not been previously documented. The silica nanoribbons are flexible and can be manipulated by electron-beam. The silica nanoribbons exhibit strong blue emission at about 467 nm, together with UV and red emissions as investigated by cathodoluminescence technique. The origins of the luminescence are attributed to various defects in the silica nanoribbons; and the intensity change of the blue emission and green emission at about 550 nm is discussed in the frame of the defect density. Our study may lead to rational design of the new silica-based materials for a wide range of applications.

  6. DYNAMICS OF STRONGLY TWISTED RELATIVISTIC MAGNETOSPHERES

    SciTech Connect

    Parfrey, Kyle; Beloborodov, Andrei M.; Hui, Lam

    2013-09-10

    Magnetar magnetospheres are believed to be strongly twisted due to shearing of the stellar crust by internal magnetic stresses. We present time-dependent axisymmetric simulations showing in detail the evolution of relativistic force-free magnetospheres subjected to slow twisting through large angles. When the twist amplitude is small, the magnetosphere moves quasi-statically through a sequence of equilibria of increasing free energy. At some twist amplitude the magnetosphere becomes tearing-mode unstable to forming a resistive current sheet, initiating large-scale magnetic reconnection in which a significant fraction of the magnetic free energy can be dissipated. This ''critical'' twist angle is insensitive to the resistive length scale. Rapid shearing temporarily stabilizes the magnetosphere beyond the critical angle, allowing the magnetosphere of a rapidly differentially rotating star to store and dissipate more free energy. In addition to these effects, shearing the surface of a rotating star increases the spindown torque applied to the star. If shearing is much slower than rotation, the resulting spikes in spindown rate can occur on timescales anywhere from the long twisting timescale to the stellar spin period or shorter, depending both on the stellar shear distribution and the existing distribution of magnetospheric twists. A model in which energy is stored in the magnetosphere and released by a magnetospheric instability therefore predicts large changes in the measured spindown rate before soft gamma repeater giant flares.

  7. Bioinspired Strong and Highly Porous Glass Scaffolds.

    PubMed

    Fu, Qiang; Saiz, Eduardo; Tomsia, Antoni P

    2011-03-22

    The quest for more efficient energy-related technologies is driving the development of porous and high-performance structural materials with exceptional mechanical strength. Natural materials achieve their strength through complex hierarchical designs and anisotropic structures that are extremely difficult to replicate synthetically. We emulate nature's design by direct-ink-write assembling of glass scaffolds with a periodic pattern, and controlled sintering of the filaments into anisotropic constructs similar to biological materials. The final product is a porous glass scaffold with a compressive strength (136 MPa) comparable to that of cortical bone and a porosity (60%) comparable to that of trabecular bone. The strength of this porous glass scaffold is ~100 times that of polymer scaffolds and 4-5 times that of ceramic and glass scaffolds with comparable porosities reported elsewhere. The ability to create both porous and strong structures opens a new avenue for fabricating scaffolds for a broad array of applications, including tissue engineering, filtration, lightweight composites, and catalyst support.

  8. Grassy Silica Nanoribbons and Strong Blue Luminescence

    PubMed Central

    Wang, Shengping; Xie, Shuang; Huang, Guowei; Guo, Hongxuan; Cho, Yujin; Chen, Jun; Fujita, Daisuke; Xu, Mingsheng

    2016-01-01

    Silicon dioxide (SiO2) is one of the key materials in many modern technological applications such as in metal oxide semiconductor transistors, photovoltaic solar cells, pollution removal, and biomedicine. We report the accidental discovery of free-standing grassy silica nanoribbons directly grown on SiO2/Si platform which is commonly used for field-effect transistors fabrication without other precursor. We investigate the formation mechanism of this novel silica nanostructure that has not been previously documented. The silica nanoribbons are flexible and can be manipulated by electron-beam. The silica nanoribbons exhibit strong blue emission at about 467 nm, together with UV and red emissions as investigated by cathodoluminescence technique. The origins of the luminescence are attributed to various defects in the silica nanoribbons; and the intensity change of the blue emission and green emission at about 550 nm is discussed in the frame of the defect density. Our study may lead to rational design of the new silica-based materials for a wide range of applications. PMID:27666663

  9. Strongly magnetized rotating dipole in general relativity

    NASA Astrophysics Data System (ADS)

    Pétri, J.

    2016-10-01

    Context. Electromagnetic waves arise in many areas of physics. Solutions are difficult to find in the general case. Aims: We numerically integrate Maxwell equations in a 3D spherical polar coordinate system. Methods: Straightforward finite difference methods would lead to a coordinate singularity along the polar axis. Spectral methods are better suited for such artificial singularities that are related to the choice of a coordinate system. When the radiating object rotates like a star, for example, special classes of solutions to Maxwell equations are worthwhile to study, such as quasi-stationary regimes. Moreover, in high-energy astrophysics, strong gravitational and magnetic fields are present especially around rotating neutron stars. Results: To study such systems, we designed an algorithm to solve the time-dependent Maxwell equations in spherical polar coordinates including general relativity and quantum electrodynamical corrections to leading order. As a diagnostic, we computed the spin-down luminosity expected for these stars and compared it to the classical or non-relativistic and non-quantum mechanical results. Conclusions: Quantum electrodynamics leads to an irrelevant change in the spin-down luminosity even for a magnetic field of about the critical value of 4.4 × 109 T. Therefore the braking index remains close to its value for a point dipole in vacuum, namely n = 3. The same conclusion holds for a general-relativistic quantum electrodynamically corrected force-free magnetosphere.

  10. PARTICLE ACCELERATION IN SUPERLUMINAL STRONG WAVES

    SciTech Connect

    Teraki, Yuto; Ito, Hirotaka; Nagataki, Shigehiro

    2015-06-01

    We calculate the electron acceleration in random superluminal strong waves (SLSWs) and radiation from them using numerical methods in the context of the termination shocks of pulsar wind nebulae. We pursue the orbit of electrons by solving the equation of motion in the analytically expressed electromagnetic turbulences. These consist of a primary SLS and isotropically distributed secondary electromagnetic waves. Under the dominance of the secondary waves, all electrons gain nearly equal energy. On the other hand, when the primary wave is dominant, selective acceleration occurs. The phase of the primary wave for electrons moving nearly along the wavevector changes very slowly compared with the oscillation of the wave, which is “phase-locked,” and such electrons are continuously accelerated. This acceleration by SLSWs may play a crucial role in pre-shock acceleration. In general, the radiation from the phase-locked population is different from the synchro-Compton radiation. However, when the amplitude of the secondary waves is not extremely weaker than that of the primary wave, the typical frequency can be estimated from synchro-Compton theory using the secondary waves. The primary wave does not contribute to the radiation because the SLSW accelerates electrons almost linearly. This radiation can be observed as a radio knot at the upstream of the termination shocks of the pulsar wind nebulae without counterparts in higher frequency ranges.

  11. Strong washout approximation to resonant leptogenesis

    SciTech Connect

    Garbrecht, Björn; Gautier, Florian; Klaric, Juraj E-mail: florian.gautier@tum.de

    2014-09-01

    We show that the effective decay asymmetry for resonant Leptogenesis in the strong washout regime with two sterile neutrinos and a single active flavour can in wide regions of parameter space be approximated by its late-time limit ε=Xsin(2φ)/(X{sup 2}+sin{sup 2}φ), where X=8πΔ/(|Y{sub 1}|{sup 2}+|Y{sub 2}|{sup 2}), Δ=4(M{sub 1}-M{sub 2})/(M{sub 1}+M{sub 2}), φ=arg(Y{sub 2}/Y{sub 1}), and M{sub 1,2}, Y{sub 1,2} are the masses and Yukawa couplings of the sterile neutrinos. This approximation in particular extends to parametric regions where |Y{sub 1,2}|{sup 2}>> Δ, i.e. where the width dominates the mass splitting. We generalise the formula for the effective decay asymmetry to the case of several flavours of active leptons and demonstrate how this quantity can be used to calculate the lepton asymmetry for phenomenological scenarios that are in agreement with the observed neutrino oscillations. We establish analytic criteria for the validity of the late-time approximation for the decay asymmetry and compare these with numerical results that are obtained by solving for the mixing and the oscillations of the sterile neutrinos. For phenomenologically viable models with two sterile neutrinos, we find that the flavoured effective late-time decay asymmetry can be applied throughout parameter space.

  12. [Strongly interacting fermion systems]. Progress report, November 15, 1992--November 14, 1993

    SciTech Connect

    Not Available

    1993-11-01

    Success was obtained in three fields: Optical properties in electronic structure program (optical activity; Se, Si); quasi-one-dimensional systems (CH{sub x}, fullerene tubule, polyaniline, etc.); other strongly interacting fermion systems (Kondo impurities interacting with conduction bands, phonon-induced decay rates for quasi-particle cyclotron orbits in simple metals, fluctuation conductivity above susperconducting transition).

  13. Strongly correlated states in ultracold atoms

    NASA Astrophysics Data System (ADS)

    Dalla Torre, Emanuele G.

    This thesis deals with novel phases and dynamical effects in strongly correlated quantum systems and is divided in two main parts. The first part deals with the effects of extended interactions on lattice bosons in one dimension. Using the density matrix renormalization group (DMRG) we showed that ultracold atoms or molecules with extended interactions, in a one dimensional optical lattice can form a novel quantum phase characterized by non-local string correlations and no broken symmetry[1]. We termed this phase a Haldane insulator due to an analogy with Haldane gapped Heisenberg spin chains. We derived a field theory description of the phase and the phase transitions from it to the conventional states, a Mott insulator and a density wave. One important outcome from this study was the observation that the topological distinction between the Haldane and Mott insulator is protected by the lattice inversion symmetry[2]. In addition, the field theoretical description allowed us to describe universal features in the dynamic response of the system to time-dependent probes[3]. In the second part, we study the effects of time-dependent noise on quantum phase transitions. We consider one particular type of noise, 1/f noise, omnipresent in low-frequency electric devices. This type of noise is scale invariant, and leads to the formation of novel non-equilibrium quantum critical states[?]. We study the effects of small static perturbations around the critical states, through a real-time renormalization group (RG) approach[4]. At the first order of our expansion (valid for short times), we find that these perturbations can lead to a sharp non-equilibrium quantum phase transition, controlled by the non-equilibrium quantum critical state. However, at the second order (valid for longer times), we actually find that the system develops a finite effective temperature, which destroys the scale invariance and turns the phase transition into a smooth crossover. Using the RG approach

  14. Strong Coupling Gauge Theories in LHC ERA

    NASA Astrophysics Data System (ADS)

    Fukaya, H.; Harada, M.; Tanabashi, M.; Yamawaki, K.

    2011-01-01

    Higgs, or techni-dilaton - composite Higgs near conformality / Koichi Yamawaki -- Phase diagram of strongly interacting theories / Francesco Sannino -- Resizing conformal windows / O. Antipin and K. Tuominen -- Nearly conformal gauge theories on the lattice / Zoltan Fodor ... [et al.] -- Going beyond QCD in lattice gauge theory / G. T. Fleming -- Phases of QCD from small to large N[symbol]: (some) lattice results / A. Deuzeman, E. Pallante and M. P. Lombardo -- Lattice gauge theory and (quasi)-conformal technicolor / D. K. Sinclair and J. B. Kogut -- Study of the running coupling constant in 10-flavor QCD with the Schrodinger functional method / N. Yamada ... [et al.] -- Study of the running coupling in twisted Polyakov scheme / T. Aoyama ... [et al.].Running coupling in strong gauge theories via the lattice / Zoltan Fodor ... [et al.] -- Higgsinoless supersymmetry and hidden gravity / Michael L. Graesser, Ryuichiro Kitano and Masafumi Kurachi -- The latest status of LHC and the EWSB physics / S. Asai -- Continuum superpartners from supersymmetric unparticles / Hsin-Chia Cheng -- Review of minimal flavor constraints for technicolor / Hidenori S. Fukano and Francesco Sannino -- Standard model and high energy Lorentz violation / Damiano Anselmi -- Dynamical electroweak symmetry breaking and fourth family / Michio Hashimoto -- Holmorphic supersymmetric Nambu-Jona-Lasino model and dynamical electroweak symmetry breaking / Dong-Won Jung, Otto C. W. Kong and Jae Sik Lee -- Ratchet model of Baryogenesis / Tatsu Takeuchi, Azusa Minamizaki and Akio Sugamoto -- Classical solutions of field equations in Einstein Gauss-Bonnet gravity / P. Suranyi, C. Vaz and L. C. R. Wijewardhana -- Black holes constitute all dark matter / Paul H. Frampton -- Electroweak precision test and Z [symbol] in the three site Higgsless model / Tomohiro Abe -- Chiral symmetry and BRST symmetry breaking, quaternion reality and the lattice simulation / Sadataka Furui -- Holographic techni-dilaton, or

  15. Dynamics of strongly perturbed planetary rings

    NASA Astrophysics Data System (ADS)

    Lewis, Mark Christopher

    2001-08-01

    This thesis looks at the dynamics of regions of rings that are located close to a small moon so that they receive a significant eccentricity from every pass by that moon. All investigations were performed with highly optimized, large N-body numerical simulations that use new boundary conditions specifically designed for this type of system. The first system explored is the Encke gap region where the small moon Pan has cleared out a 325 km region of Saturn's rings. Simulations indicate that the behavior of this system is significantly more complex than what is found by standard fluid models of ring dynamics due largely to the fact that the particles epicyclic phases are aligned. The wake peaks decline exponentially at the end of the simulations and the dependence of this rate of this decline was examined as a function of optical depth, particle size, and coefficient of restitution. The variations are non-monotonical with optical depth and coefficient of restitution. The alignment of epicyclic phases in the wakes enables the guiding centers of the particles to undergo efficient radial migration. This process allows the particle guiding centers to group at the edges of the simulation region and in some cases is seen to result in ringlet formation. For regions more distant from the perturber than the edge of the Encke gap, the synodic periods are shorter and as a result, the forced eccentricities do not damp out completely in a synodic period. When this occurs, the presence of Lindblad resonances is seen. These resonances are observed to induce periodic structures in regions far from the Encke gap and speed narrow ringlet formation in systems resembling Saturn's F-ring. However, the narrow rings do not have to be located in resonances to be maintained, as the standard theory of shepherding would imply. Simulations including size distributions exhibited a buildup of small particles at the boundaries, in agreement with Voyager observations. Simulations involving self

  16. Universal spin transport in a strongly interacting Fermi gas.

    PubMed

    Sommer, Ariel; Ku, Mark; Roati, Giacomo; Zwierlein, Martin W

    2011-04-14

    Transport of fermions, particles with half-integer spin, is central to many fields of physics. Electron transport runs modern technology, defining states of matter such as superconductors and insulators, and electron spin is being explored as a new carrier of information. Neutrino transport energizes supernova explosions following the collapse of a dying star, and hydrodynamic transport of the quark-gluon plasma governed the expansion of the early Universe. However, our understanding of non-equilibrium dynamics in such strongly interacting fermionic matter is still limited. Ultracold gases of fermionic atoms realize a pristine model for such systems and can be studied in real time with the precision of atomic physics. Even above the superfluid transition, such gases flow as an almost perfect fluid with very low viscosity when interactions are tuned to a scattering resonance. In this hydrodynamic regime, collective density excitations are weakly damped. Here we experimentally investigate spin excitations in a Fermi gas of (6)Li atoms, finding that, in contrast, they are maximally damped. A spin current is induced by spatially separating two spin components and observing their evolution in an external trapping potential. We demonstrate that interactions can be strong enough to reverse spin currents, with components of opposite spin reflecting off each other. Near equilibrium, we obtain the spin drag coefficient, the spin diffusivity and the spin susceptibility as a function of temperature on resonance and show that they obey universal laws at high temperatures. In the degenerate regime, the spin diffusivity approaches a value set by [planck]/m, the quantum limit of diffusion, where [planck]/m is Planck's constant divided by 2π and m the atomic mass. For repulsive interactions, our measurements seem to exclude a metastable ferromagnetic state.

  17. Strong lensing in the inner halo of galaxy clusters

    NASA Astrophysics Data System (ADS)

    Saez, C.; Campusano, L. E.; Cypriano, E. S.; Sodré, L.; Kneib, J.-P.

    2016-08-01

    We present an axially symmetric formula to calculate the probability of finding gravitational arcs in galaxy clusters, being induced by their massive dark matter haloes, as a function of clusters redshifts and virial masses. The formula includes the ellipticity of the clusters dark matter potential by using a pseudo-elliptical approximation. The probabilities are calculated and compared for two dark matter halo profiles, the Navarro, Frenk and White (NFW) and the non-singular-isothermal-sphere (NSIS). We demonstrate the power of our formulation through a Kolmogorov-Smirnov (KS) test on the strong lensing statistics of an X-ray bright sample of low-redshift Abell clusters. This KS test allows us to establish limits on the values of the concentration parameter for the NFW profile (c_Δ) and the core radius for the NSIS profile (rc), which are related to the lowest cluster redshift (zcut) where strong arcs can be observed. For NFW dark matter profiles, we infer cluster haloes with concentrations that are consistent to those predicted by ΛCDM simulations. As for NSIS dark matter profiles, we find only upper limits for the clusters core radii and thus do not rule out a purely SIS model. For alternative mass profiles, our formulation provides constraints through zcut on the parameters that control the concentration of mass in the inner region of the clusters haloes. We find that zcut is expected to lie in the 0.0-0.2 redshift, highlighting the need to include very low-z clusters in samples to study the clusters mass profiles.

  18. Strongly nonlinear dynamics of electrolytes in large ac voltages

    NASA Astrophysics Data System (ADS)

    Højgaard Olesen, Laurits; Bazant, Martin Z.; Bruus, Henrik

    2010-07-01

    We study the response of a model microelectrochemical cell to a large ac voltage of frequency comparable to the inverse cell relaxation time. To bring out the basic physics, we consider the simplest possible model of a symmetric binary electrolyte confined between parallel-plate blocking electrodes, ignoring any transverse instability or fluid flow. We analyze the resulting one-dimensional problem by matched asymptotic expansions in the limit of thin double layers and extend previous work into the strongly nonlinear regime, which is characterized by two features—significant salt depletion in the electrolyte near the electrodes and, at very large voltage, the breakdown of the quasiequilibrium structure of the double layers. The former leads to the prediction of “ac capacitive desalination” since there is a time-averaged transfer of salt from the bulk to the double layers, via oscillating diffusion layers. The latter is associated with transient diffusion limitation, which drives the formation and collapse of space-charge layers, even in the absence of any net Faradaic current through the cell. We also predict that steric effects of finite ion sizes (going beyond dilute-solution theory) act to suppress the strongly nonlinear regime in the limit of concentrated electrolytes, ionic liquids, and molten salts. Beyond the model problem, our reduced equations for thin double layers, based on uniformly valid matched asymptotic expansions, provide a useful mathematical framework to describe additional nonlinear responses to large ac voltages, such as Faradaic reactions, electro-osmotic instabilities, and induced-charge electrokinetic phenomena.

  19. Effective Theories Of The Strong Interaction

    SciTech Connect

    Dr. Ubirajara van Kolck

    2004-07-31

    This is the final report corresponding to the full funding period (08/01-07/04) in the Department of Energy Outstanding Junior Investigator Grant DE-FG03-01ER41196. The development of an understanding of the interplay between perturbative and non-perturbative effects in strong-interacting systems forms the broad context of this research. The main thrust is the application of effective theories to QCD. Topics included a new power counting in the pionful effective theory, low-energy Compton scattering, charge-symmetry breaking in pion production and in the two-nucleon potential, parity violation, coupled-channel scattering, shallow resonances and halo nuclei, chiral symmetry in the baryon spectrum, existence of a tetraquark state, and molecular meson states. DOE grant DE-FG03-01ER41196 was used to partially support in the period 08/01-07/04 the research activities of the Principal Investigator, Dr. Ubirajara van Kolck, one post-doctoral research associate, Dr. Boris A. Gelman, and one graduate student, Mr. Will Hockings. During the grant period the PI was first Assistant then Associate Professor of Physics at the University of Arizona (UA), and a RHIC Physics Fellow at the RIKEN-BNL Research Center (RBRC). The association with RBRC ended in the Summer of 2004. Since September of 2002 the PI has also been partially supported by a Sloan Research Fellowship. Dr. Boris Gelman was supported by the grant from September 2002 to May 2004. He joined the UA after receiving a Ph.D. from the University of Maryland in the Summer of 2002. He left to take a research associate position in the nuclear theory group of the State University of New York at Stony Brook. The support of a post-doctoral researcher on this grant for two years was only possible by carrying over first- and second-year funds to later years. In addition, Mr. William Hockings started doing research under the PI's guidance. Mr. Hockings took Independent Study courses with the PI, while working as a teaching

  20. The Commercial TREMOR Strong-Motion Seismograph

    NASA Astrophysics Data System (ADS)

    Evans, J. R.; Hamstra, R. H.; Kuendig, C.; Camina, P.

    2001-12-01

    The emergence of major seismological and earthquake-engineering problems requiring large, dense instrument arrays led several of us to investigate alternate solutions. Evans and Rogers (USGS Open File Report 95-555, 1995) and Evans (USGS Open File Report 98-109, 1998) demonstrated the efficacy of low-cost robust silicon accelerometers in strong-motion seismology, making possible a vast increase in the spatial density of such arrays. The 1998 design displays true 16-bit performance and excellent robustness and linearity---13 of these prototype near-real-time instruments are deployed in Oakland, California, and have recorded data from seven small events (up to 5.7 %g). Since this technology is a radical departure from past efforts, it was necessary for the USGS to develop the sensor and demonstrate its efficacy thoroughly. Since it is neither practical nor appropriate for the USGS to produce instrumentation beyond a demonstration phase, the US Geological Survey and GeoSIG Ltd undertook a collaborative effort (a ``CRAD'') to commercialize the new technology. This effort has resulted in a fully temperature-compensated 16-bit system, the GeoSIG GT-316, announced in April, 2001, combining the ICS-3028 TM-based USGS sensor, temperature compensation technique, and peak ground velocity (PGV) computation with a highly customized 16-bit GeoSIG recorder. The price has not been set but is likely to be around \\2000 in large quantities. The result is a near-real-time instrument telemetering peak ground acceleration (PGA) and PGV about 90 s after onset of the P wave, then minutes later transmitting the waveform. The receiving software, ``HomeBase()'', also computes spectral acceleration, S_{a}. PGA, PGV, S_{a}, and waveforms are forwarded immediately by HomeBase() for ShakeMap generation and other uses. Shaking metrics from the prototypes in Oakland are consistently among the first to arrive for the northern California ShakeMap. For telemetry we use a low-cost always

  1. Strong plasmon coupling in self-assembled superparamagnetic nanoshell chains

    NASA Astrophysics Data System (ADS)

    Xiong, Min; Jin, Xiulong; Ye, Jian

    2016-02-01

    Construction of ordered patterns of plasmonic nanoparticles is greatly important for nanophotonics relevant applications. We have reported a facile and low-cost magnetic field induced self-assembly approach to construct plasmonic superparamagnetic nanoshell (SN) chains up to several hundred micrometers in a few seconds in a large area without templates or other assistance processes. Experimental and theoretical investigations of the near- and far-field optical properties indicate that the super- and sub-radiant modes of the SN chains continuously redshift with the increase of SN number and the Fano resonance emerges in the infinite double- and triple-line SN chains. Strong plasmon coupling effects in the SN chains result in great electric field enhancements at visible and infrared wavelengths, which indicates that these chain structures potentially can be used as a common substrate for both surface enhanced Raman scattering (SERS) and surface-enhanced infrared absorption (SEIRA) application. This fabrication method also offers a general strategy alternative to top-down processing that enables the construction of nanostructures for metamaterials, electromagnetic energy transport, and optical waveguide.Construction of ordered patterns of plasmonic nanoparticles is greatly important for nanophotonics relevant applications. We have reported a facile and low-cost magnetic field induced self-assembly approach to construct plasmonic superparamagnetic nanoshell (SN) chains up to several hundred micrometers in a few seconds in a large area without templates or other assistance processes. Experimental and theoretical investigations of the near- and far-field optical properties indicate that the super- and sub-radiant modes of the SN chains continuously redshift with the increase of SN number and the Fano resonance emerges in the infinite double- and triple-line SN chains. Strong plasmon coupling effects in the SN chains result in great electric field enhancements at visible

  2. Design and synthesis of organic semiconductors with strong noncovalent interactions

    NASA Astrophysics Data System (ADS)

    Tucker, Neil Maxwell

    2008-10-01

    The development of organic molecules as active components of electronic and optoelectronic devices has seen unprecedented progress in the past decade. This attention is primarily due to the potential impact on large-area and low-cost fabrication of devices, integrated circuits, flexible displays, and in particular, organic field-effect transistors (OFETs). Organic semiconductors that pack face-to-face in the solid state are of particular interest since they are known to self-assemble into 1-D nanostructures due to strong pi-pi interactions. Engineering linear/planar molecules to pack face-to-face is challenging because the interacting forces between organic molecules are relatively weak. Three approaches were used to induce face-to-face packing in organic semiconductors: (1) several derivatives of hexaazatrinaphthylene, (HATNA), were designed which vary in their degree of hydrogen bonding, rigidity, and electron deficiency. Hydrogen bonded moieties induced strong interaction between cores that formed robust nanowires when subjected to nonpolar solvents. While no device data was measured for these materials, substituents location was found to have a profound effect on the electronic properties; (2) Inspired by S···S interactions found in tetrathiafulvalene (TTF) and electrostatic interactions found in 1,2,5-thiadiazole derivatives, a hybrid of these two molecules was developed (BT-TTF-1). Short intermolecular S···S, S···N, and S···C contacts define the solid state structure of BT-TTF-1 single crystals which pi-stack along the [100]. Theoretical insight into the nature of the interactions revealed that the close contacts are electrostatic in origin rather than the result of London dispersion forces. Thermal evaporation yields a network of poorly connected crystals which significantly limits the mobility. Solvent-cast single-crystal nanowire transistors showed mobilities as large as 0.36 cm2/Vs with excellent device characteristics underscoring the

  3. Neutron limit on the strongly-coupled chameleon field

    NASA Astrophysics Data System (ADS)

    Li, K.; Arif, M.; Cory, D. G.; Haun, R.; Heacock, B.; Huber, M. G.; Nsofini, J.; Pushin, D. A.; Saggu, P.; Sarenac, D.; Shahi, C. B.; Skavysh, V.; Snow, W. M.; Young, A. R.; Index Collaboration

    2016-03-01

    The physical origin of the dark energy that causes the accelerated expansion rate of the Universe is one of the major open questions of cosmology. One set of theories postulates the existence of a self-interacting scalar field for dark energy coupling to matter. In the chameleon dark energy theory, this coupling induces a screening mechanism such that the field amplitude is nonzero in empty space but is greatly suppressed in regions of terrestrial matter density. However measurements performed under appropriate vacuum conditions can enable the chameleon field to appear in the apparatus, where it can be subjected to laboratory experiments. Here we report the most stringent upper bound on the free neutron-chameleon coupling in the strongly coupled limit of the chameleon theory using neutron interferometric techniques. Our experiment sought the chameleon field through the relative phase shift it would induce along one of the neutron paths inside a perfect crystal neutron interferometer. The amplitude of the chameleon field was actively modulated by varying the millibar pressures inside a dual-chamber aluminum cell. We report a 95% confidence level upper bound on the neutron-chameleon coupling β ranging from β <4.7 ×106 for a Ratra-Peebles index of n =1 in the nonlinear scalar field potential to β <2.4 ×107 for n =6 , one order of magnitude more sensitive than the most recent free neutron limit for intermediate n . Similar experiments can explore the full parameter range for chameleon dark energy in the foreseeable future.

  4. Strongly Lacunary Ward Continuity in 2-Normed Spaces

    PubMed Central

    Çakalli, Hüseyin; Ersan, Sibel

    2014-01-01

    A function f defined on a subset E of a 2-normed space X is strongly lacunary ward continuous if it preserves strongly lacunary quasi-Cauchy sequences of points in E; that is, (f(xk)) is a strongly lacunary quasi-Cauchy sequence whenever (xk) is strongly lacunary quasi-Cauchy. In this paper, not only strongly lacunary ward continuity, but also some other kinds of continuities are investigated in 2-normed spaces. PMID:25050397

  5. Quantum phase transition in strongly correlated systems

    NASA Astrophysics Data System (ADS)

    Jiang, Longhua

    In this thesis, we investigated the strongly correlated phenomena in bilayer quantum Hall effect, inhomogeneous superconductivity and Boson Hubbard model. Bilayer quantum Hall system is studied in chapter 2. By using the Composite Boson (CB) theory developed by J. Ye, we derive the ground state, quasihole and a quasihole-pair wave functions from the CB theory and its dual action. We find that the ground state wave function is the product of two parts, one in the charge sector which is the well known Halperin's (111) wave function and the other in the spin sector which is non-trivial at any finite d due to the gapless mode. So the total groundstate wave function differs from the well known (111) wave function at any finite d. In addition to commonly known multiplicative factors, the quasihole and quasihole-pair wave functions also contain non-trivial normalization factors multiplying the correct ground state wave function. Then we continue to study the quantum phase transition from the excitonic superfluid (ESF) to a possible pseudo-spin density wave (PSDW) at some intermediate distances driven by the magneto-roton minimum collapsing at a finite wavevector. We analyze the properties of the PSDW and explicitly show that a square lattice is the favored lattice. We suggest that correlated hopping of vacancies in the active and passive layers in the PSDW state leads to very large and temperature-dependent drag, consistent with the experimental data. Comparisons with previous microscopic numerical calculations are made. Further experimental implications are given. In chapter 3, we investigate inhomogeneous superconductivity. Starting from the Ginzburg-Landau free energy describing the normal state to Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) state transition, we evaluate the free energy of seven most common lattice structures: stripe, square, triangular, Simple Cubic (SC), Face centered Cubic (FCC), Body centered Cubic (BCC) and Quasicrystal (QC). We find that the stripe

  6. Induced Abortion

    MedlinePlus

    ... Education & Events Advocacy For Patients About ACOG Induced Abortion Home For Patients Search FAQs Induced Abortion Page ... Induced Abortion FAQ043, May 2015 PDF Format Induced Abortion Special Procedures What is an induced abortion? What ...

  7. Nonlinear parallel momentum transport in strong electrostatic turbulence

    SciTech Connect

    Wang, Lu Wen, Tiliang; Diamond, P. H.

    2015-05-15

    Most existing theoretical studies of momentum transport focus on calculating the Reynolds stress based on quasilinear theory, without considering the nonlinear momentum flux-〈v{sup ~}{sub r}n{sup ~}u{sup ~}{sub ∥}〉. However, a recent experiment on TORPEX found that the nonlinear toroidal momentum flux induced by blobs makes a significant contribution as compared to the Reynolds stress [Labit et al., Phys. Plasmas 18, 032308 (2011)]. In this work, the nonlinear parallel momentum flux in strong electrostatic turbulence is calculated by using a three dimensional Hasegawa-Mima equation, which is relevant for tokamak edge turbulence. It is shown that the nonlinear diffusivity is smaller than the quasilinear diffusivity from Reynolds stress. However, the leading order nonlinear residual stress can be comparable to the quasilinear residual stress, and so may be important to intrinsic rotation in tokamak edge plasmas. A key difference from the quasilinear residual stress is that parallel fluctuation spectrum asymmetry is not required for nonlinear residual stress.

  8. Strong anticonvulsant effect of thalidomide on amygdaloid kindling.

    PubMed

    Palencia, Guadalupe; Rubio, Carmen; Custodio-Ramirez, Veronica; Paz, Carlos; Sotelo, Julio

    2011-08-01

    Thalidomide was synthesized more than 50 years ago as hypnotic sedative with unique pharmacologic properties. Recently, we have described a notorious anticonvulsant effect of thalidomide on pentylenetetrazole-induced seizures. Here, we report the results of thalidomide administration on amygdaloid kindling. A total of 100 male Wistar rats were implanted with brain electrodes in the basolateral amygdaloid nucleus and the sensory motor cortex. After surgery the animals received a daily electric stimulus through the amygdaline electrode (500 μA intensity, 60 Hz frequency, 1 ms duration) until seizures appeared. The following treatment groups were made: (a) controls; (b) rats treated daily with thalidomide (10 mg/kg) or with topiramate (80 mg/kg); (c) rats treated with different doses of thalidomide. Significant reduction in the after-discharge and retard of behavioral stages were observed in rats treated with thalidomide or with topiramate as compared with controls (p<0.01): Also, a similar anticonvulsant outcome of thalidomide therapy was obtained with doses of either 2.5, 5, 10 or 50 mg/kg; at 100 mg/kg all epileptic activity was suppressed. Anticonvulsant efficacy of thalidomide was superior in most parameters than that obtained with topiramate. In amygdaloid kindling, which simulates human epilepsy characterized by focal seizures secondarily generalized, low doses of thalidomide display strong anticonvulsant properties.

  9. Strong light-field effects in correlated oraganic conductors

    NASA Astrophysics Data System (ADS)

    Iwai, Shinichiro; Kawakami, Yohei; Naitoh, Yota; Itoh, Hirotake; Ishihara, Sumio; Yonemitsu, Kenji

    Optical responses of organic conductors have attracted much attentions, because they exhibit ultrafast solid-state phase transitions in the conducting and/or dielectric natures upon photo-excitations. In this decade, photoinduced melting of correlated insulators with clear charge gap have been extensively investigated. On the other hand, optical rsponses of correlated metal has not been studied well. Here, we describe a charge localization induced by the 9.3 MV/cm instantaneous electric field of a 1.5 cycle (7 fs) infrared pulse in an organic conductor alpha- (bis[ethylenedithio]-tetrathiafulvelene)2I3. A large reflectivity change of 30 percent and a coherent charge oscillation along the time axis reflect the opening of the charge ordering gap in the metallic phase. This optical freezing of charges, which is the reverse of the photoinduced melting of electronic orders, is attributed to the 10 percent reduction of t driven by the strong, high-frequency electric field. Furthermore, the contribution of Coulomb repulsion will be discussed on the basis of the polarization dependence of the pump light and the theory.

  10. Mechanism for strong magnetoelectric coupling in dilute magnetic ferroelectrics

    NASA Astrophysics Data System (ADS)

    Weston, L.; Cui, X. Y.; Ringer, S. P.; Stampfl, C.

    2016-11-01

    The manipulation of atomic-scale magnetization is important from both a fundamental and a practical perspective. Using first-principles density-functional-theory calculations within the hybrid functional approach, we systematically study spin-lattice coupling effects for isolated 3 d4-3 d7 transition-metal dopants in a nonmagnetic, ferroelectric PbTiO3 host material. When present at the B-site, a low-spin (or intermediate-spin) to high-spin crossover induces marked ferroelectric-like distortions in the local geometry, characterized by a shift of the dopant ion with respect to the surrounding O6 octahedral cage. The origins of this microscopic multiferroic effect are discussed in terms of the pseudo-Jahn-Teller theory for ferroelectricity. The possibility to exploit this phenomenon to achieve strong magnetoelectric coupling, including controlled spin switching, is also investigated. These results provide a further understanding of ferroelectricity and multiferroicity in perovskite oxides, and they suggest a possible pathway to manipulate single atomic spins in semiconductor solid solutions.

  11. Natural cold baryogenesis from strongly interacting electroweak symmetry breaking

    SciTech Connect

    Konstandin, Thomas; Servant, Géraldine E-mail: geraldine.servant@cern.ch

    2011-07-01

    The mechanism of ''cold electroweak baryogenesis'' has been so far unpopular because its proposal has relied on the ad-hoc assumption of a period of hybrid inflation at the electroweak scale with the Higgs acting as the waterfall field. We argue here that cold baryogenesis can be naturally realized without the need to introduce any slow-roll potential. Our point is that composite Higgs models where electroweak symmetry breaking arises via a strongly first-order phase transition provide a well-motivated framework for cold baryogenesis. In this case, reheating proceeds by bubble collisions and we argue that this can induce changes in Chern-Simons number, which in the presence of new sources of CP violation commonly lead to baryogenesis. We illustrate this mechanism using as a source of CP violation an effective dimension-six operator which is free from EDM constraints, another advantage of cold baryogenesis compared to the standard theory of electroweak baryogenesis. Our results are general as they do not rely on any particular UV completion but only on a stage of supercooling ended by a first-order phase transition in the evolution of the universe, which can be natural if there is nearly conformal dynamics at the TeV scale. Besides, baryon-number violation originates from the Standard Model only.

  12. Polaronic approach to strongly correlated electron systems with strong electron-phonon interaction

    NASA Astrophysics Data System (ADS)

    Makarov, I. A.; Shneyder, E. I.; Kozlov, P. A.; Ovchinnikov, S. G.

    2015-10-01

    The three-band p -d model of strongly correlated electrons interacting with optical phonons via diagonal and off-diagonal electron-phonon interactions is considered within the cluster perturbation theory. In the beginning, the exact diagonalization of the Hamiltonian of a CuO4 cluster results in the construction of local polaronic eigenstates |p > with hole numbers nh=0 ,1 ,2 per unit cell. The intercluster hoppings and interactions are exactly written in terms of Hubbard operators Xfp q=|p > at site f . The Fermi-type single-electron quasiparticle dispersion and spectral weight are calculated for the undoped antiferromagnetic parent insulator like La2CuO4 . The quasiparticle dispersion of Hubbard polarons is determined by a hybridization of the Hubbard fermion subbands with local Franck-Condon resonances so the main polaronic effect of the quasiparticle band structure is a splitting of the Hubbard bands on the number of Hubbard polaron subbands. Increasing of the EPI constant results in an increase of splitting, decrease of the subband width, transfer of the spectral weight to high-energy multiphonon excitations, and subsequent localization of the charge carriers. Herewith, the effect of such renormalization for the conduction band and the valence one differs depending on the ratio of the diagonal and off-diagonal EPI. In the framework of the GTB method, the Franck-Condon broadening of the spectral function of polaronic excitations is also reproduced for strongly correlated systems with strong electron-phonon interaction.

  13. Low-energy Model for Strongly Correlated Oxides

    NASA Astrophysics Data System (ADS)

    Liu, Shiu

    . Previous theoretical T-matrix and quantum Monte Carlo (QMC) studies, which include only the dilution effect of impurities, show a large discrepancy with experimental neutron scattering and nuclear quadrupole resonance (NQR) data in the doping dependence of the staggered magnetization at low doping. We demonstrate that this discrepancy is eliminated by including zinc orbitals in the three-band Hubbard model and by including impurity-induced frustrations into the effective spin model with realistic CuO2 parameters. Recent experimental study shows a significantly stronger suppression of spin stiffness in the case of Zn-doped La2CuO4 compared to the Mg-doped case and thus gives a strong support to our theory. Different site-diluting dopants with different electron configurations affect the magnetism of the whole system differently. We argue that the available impurity orbitals are crucial in deriving theoretical models for the site-diluted systems and the proposed impurity-induced frustrations should be important in other strongly correlated oxides and charge-transfer insulators.

  14. Redox processes at a nanostructured interface under strong electric fields

    NASA Astrophysics Data System (ADS)

    Steurer, Wolfram; Surnev, Svetlozar; Netzer, Falko P.; Sementa, Luca; Negreiros, Fabio R.; Barcaro, Giovanni; Durante, Nicola; Fortunelli, Alessandro

    2014-08-01

    mechanism. The proposed approach can be easily implemented and generally applied to a wide range of interfacial systems, thus opening new opportunities for the manipulation of film growth and reaction processes at solid surfaces under strong external fields. Electronic supplementary information (ESI) available: Details of theoretical modeling: computational details of the density-functional calculations, selected results of static DFT calculations including an electric field, definition of the electronic model Hamiltonian and plots of real orbitals involved in DEA, and the definition of the nuclear PES. Experimental additional information: a typical Fowler-Nordheim I-V plot, estimate of experimental reduction efficiency, comparison of AES spectra obtained before and after electric-field exposure, induced NiO reduction by an inhomogeneous electric field, images of sputtered Ag(100) exposed to strong electric fields in the presence of an oxygen atmosphere and images of field-induced NiO reduction by an STM tip below -1.2 V. See DOI: 10.1039/c4nr02882a

  15. Identification of a Novel Strong and Ubiquitous Promoter/Enhancer in the Silkworm Bombyx mori

    PubMed Central

    Tsubota, Takuya; Uchino, Keiro; Suzuki, Takao K; Tanaka, Hiromitsu; Kayukawa, Takumi; Shinoda, Tetsuro; Sezutsu, Hideki

    2014-01-01

    Transgenic techniques offer a valuable tool for determining gene functions. Although various promoters are available for use in gene overexpression, gene knockdown, and identification of transgenic individuals, there is nevertheless a lack of versatile promoters for such studies, and this dearth acts as a bottleneck, especially with regard to nonmodel organisms. Here, we succeeded in identifying a novel strong and ubiquitous promoter/enhancer in the silkworm. We identified a unique silkworm strain whose reporter gene showed strong and ubiquitous expression during the establishment of enhancer trap strains. In this strain, the transposon was inserted into the 5′UTR of hsp90, a housekeeping gene that is abundantly expressed in a range of tissues. To determine whether the promoter/enhancer of hsp90 could be used to induce strong gene expression, a 2.9-kb upstream genomic fragment of hsp90 was isolated (hsp90P2.9k), and its transcriptional activation activity was examined. Strikingly, hsp90P2.9k induced strong gene expression in silkworm cell cultures and also strongly induced gene expression in various tissues and developmental stages of the silkworm. hsp90P2.9k also exhibited significant promoter/enhancer activity in Sf9, a cell culture from the armyworm, suggesting that this fragment might possibly be used as a gene expression tool in other Lepidoptera. We further found that 2.0 kb of hsp90P2.9k is sufficient for the induction of strong gene expression. We believe that this element will be of value for a range of studies such as targeted gene overexpression, gene knockdown and marker gene expression, not only in the silkworm but also in other insect species. PMID:24875626

  16. Identification of a novel strong and ubiquitous promoter/enhancer in the silkworm Bombyx mori.

    PubMed

    Tsubota, Takuya; Uchino, Keiro; Suzuki, Takao K; Tanaka, Hiromitsu; Kayukawa, Takumi; Shinoda, Tetsuro; Sezutsu, Hideki

    2014-05-28

    Transgenic techniques offer a valuable tool for determining gene functions. Although various promoters are available for use in gene overexpression, gene knockdown, and identification of transgenic individuals, there is nevertheless a lack of versatile promoters for such studies, and this dearth acts as a bottleneck, especially with regard to nonmodel organisms. Here, we succeeded in identifying a novel strong and ubiquitous promoter/enhancer in the silkworm. We identified a unique silkworm strain whose reporter gene showed strong and ubiquitous expression during the establishment of enhancer trap strains. In this strain, the transposon was inserted into the 5'UTR of hsp90, a housekeeping gene that is abundantly expressed in a range of tissues. To determine whether the promoter/enhancer of hsp90 could be used to induce strong gene expression, a 2.9-kb upstream genomic fragment of hsp90 was isolated (hsp90(P2.9k)), and its transcriptional activation activity was examined. Strikingly, hsp90(P2.9k) induced strong gene expression in silkworm cell cultures and also strongly induced gene expression in various tissues and developmental stages of the silkworm. hsp90(P2.9k) also exhibited significant promoter/enhancer activity in Sf9, a cell culture from the armyworm, suggesting that this fragment might possibly be used as a gene expression tool in other Lepidoptera. We further found that 2.0 kb of hsp90(P2.9k) is sufficient for the induction of strong gene expression. We believe that this element will be of value for a range of studies such as targeted gene overexpression, gene knockdown and marker gene expression, not only in the silkworm but also in other insect species.

  17. On strongly GA-convex functions and stochastic processes

    SciTech Connect

    Bekar, Nurgül Okur; Akdemir, Hande Günay; İşcan, İmdat

    2014-08-20

    In this study, we introduce strongly GA-convex functions and stochastic processes. We provide related well-known Kuhn type results and Hermite-Hadamard type inequality for strongly GA-convex functions and stochastic processes.

  18. On strongly GA-convex functions and stochastic processes

    NASA Astrophysics Data System (ADS)

    Bekar, Nurgül Okur; Akdemir, Hande Günay; Işcan, Imdat

    2014-08-01

    In this study, we introduce strongly GA-convex functions and stochastic processes. We provide related well-known Kuhn type results and Hermite-Hadamard type inequality for strongly GA-convex functions and stochastic processes.

  19. Properties of a strongly focused Gaussian beam with an off-axis vortex

    NASA Astrophysics Data System (ADS)

    Zhao, Xinying; Zhang, Jingcheng; Pang, Xiaoyan; Wan, Guobin

    2017-04-01

    The intensity distribution and the phase properties, especially the Gouy phase and the phase singularities are studied in a strongly focused Gaussian beam with an off-axis vortex. The symmetry relation of the focused field is also derived. It is found that the off-axis vortex induces a rotation of the field pattern, the transverse focal shift, and the asymmetric distribution of the phase singularities. Our results also show that the initial position of the off-axis vortex in the incident beam strongly influences the distance of the transverse focal shift, but does not have an effect on the Gouy phase along the central axis.

  20. Emergent Interacting Spin Islands in a Depleted Strong-Leg Heisenberg Ladder

    NASA Astrophysics Data System (ADS)

    Schmidiger, D.; Povarov, K. Yu.; Galeski, S.; Reynolds, N.; Bewley, R.; Guidi, T.; Ollivier, J.; Zheludev, A.

    2016-06-01

    Properties of the depleted Heisenberg spin ladder material series (C7 H10 N )2Cu1 -zZnz Br4 have been studied by the combination of magnetic measurements and neutron spectroscopy. Disorder-induced degrees of freedom lead to a specific magnetic response, described in terms of emergent strongly interacting "spin island" objects. The structure and dynamics of the spin islands is studied by high-resolution inelastic neutron scattering. This allows us to determine their spatial shape and to observe their mutual interactions, manifested by strong spectral in-gap contributions.

  1. Transient particle acceleration in strongly magnetized neutron stars. II - Effects due to a dipole field geometry

    NASA Technical Reports Server (NTRS)

    Fatuzzo, Marco; Melia, Fulvio

    1991-01-01

    Sheared Alfven waves generated by nonradial crustal disturbances above the polar cap of a strongly magnetized neutron star induce an electric field component parallel to B. An attempt is made to determine the manner in which the strong radial dependence of B affects the propagation of these sheared Alfven waves, and whether this MHD process is still an effective particle accelerator. It is found that although the general field equation is quite complicated, a simple wavelike solution can still be obtained under the conditions of interest for which the Alfven phase velocity decouples from the wave equation. The results may be applicable to gamma-ray burst sources.

  2. Relaxation of a Classical Spin Coupled to a Strongly Correlated Electron System

    NASA Astrophysics Data System (ADS)

    Sayad, Mohammad; Rausch, Roman; Potthoff, Michael

    2016-09-01

    A classical spin which is antiferromagnetically coupled to a system of strongly correlated conduction electrons is shown to exhibit unconventional real-time dynamics which cannot be described by Gilbert damping. Depending on the strength of the local Coulomb interaction U , the two main electronic dissipation channels, namely transport of excitations via correlated hopping and via excitations of correlation-induced magnetic moments, become active on largely different time scales. We demonstrate that correlations can lead to a strongly suppressed relaxation which so far has been observed in purely electronic systems only and which is governed here by proximity to the divergent magnetic time scale in the infinite-U limit.

  3. Strong interaction of a transmon qubit with 1D band-gap medium

    NASA Astrophysics Data System (ADS)

    Liu, Yanbing; Sadri, Darius; Houck, Andrew; Bronn, Nicholas; Chow, Jerry; Gambetta, Jay

    2015-03-01

    The spontaneous emission of an atom will be enhanced or suppressed in a structured vacuum, commonly known as Purcell effect. Moreover, in a frequency gap medium, an atom-photon bound state is predicted to exist in the band gap, causing the localization of light. Here using the technology of circuit quantum electrodynamics, we experimentally explore this mechanism by fabricating a microwave step-impedance filter strongly coupled to a transmon qubit. Standard transmission and spectroscopy measurements support the existence of atom-photon bound states in the system. Correlation measurement shows that the atom-photon interaction induces strong correlation of the transmitted light through the system. Thanks support from IARPA

  4. Nonlinear Quantum Optics in a Waveguide: Distinct Single Photons Strongly Interacting at the Single Atom Level

    SciTech Connect

    Kolchin, Pavel; Oulton, Rupert F.; Zhang Xiang

    2011-03-18

    We propose a waveguide-QED system where two single photons of distinct frequency or polarization interact strongly. The system consists of a single ladder-type three level atom coupled to a waveguide. When both optical transitions are coupled strongly to the waveguide's mode, we show that a control photon tuned to the upper transition induces a {pi} phase shift and tunneling of a probe photon tuned to the otherwise reflective lower transition. Furthermore, the system exhibits single photon scattering by a classical control beam. Waveguide-QED schemes could be an alternative to high quality cavities or dense atomic ensembles in quantum information processing.

  5. 7 CFR 51.906 - Well developed and strong.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 2 2012-01-01 2012-01-01 false Well developed and strong. 51.906 Section 51.906 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards....906 Well developed and strong. Well developed and strong means that the main and lateral stems...

  6. 7 CFR 51.906 - Well developed and strong.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 2 2011-01-01 2011-01-01 false Well developed and strong. 51.906 Section 51.906 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards....906 Well developed and strong. Well developed and strong means that the main and lateral stems...

  7. 7 CFR 51.906 - Well developed and strong.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Well developed and strong. 51.906 Section 51.906 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards....906 Well developed and strong. Well developed and strong means that the main and lateral stems...

  8. 7 CFR 51.906 - Well developed and strong.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 2 2014-01-01 2014-01-01 false Well developed and strong. 51.906 Section 51.906 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards... Vinifera Type) 1 Definitions § 51.906 Well developed and strong. Well developed and strong means that...

  9. 7 CFR 51.906 - Well developed and strong.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 2 2013-01-01 2013-01-01 false Well developed and strong. 51.906 Section 51.906 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards... Vinifera Type) 1 Definitions § 51.906 Well developed and strong. Well developed and strong means that...

  10. Quantum control of molecular fragmentation in strong laser fields

    NASA Astrophysics Data System (ADS)

    Zohrabi, Mohammad

    Present advances in laser technology allow the production of ultrashort (<˜5 fs, approaching single cycle at 800 nm), intense tabletop laser pulses. At these high intensities laser-matter interactions cannot be described with perturbation theory since multiphoton processes are involved. This is in contrast to photodissociation by the absorption of a single photon, which is well described by perturbation theory. For example, at high intensities (<˜5x1013 W/cm2) the fragmentation of molecular hydrogen ions has been observed via the absorption of three or more photons. In another example, an intriguing dissociation mechanism has been observed where molecular hydrogen ions seem to fragment by apparently absorbing no photons. This is actually a two photon process, photoabsorption followed by stimulated emission, resulting in low energy fragments. We are interested in exploring these kinds of multiphoton processes. Our research group has studied the dynamics and control of fragmentation induced by strong laser fields in a variety of molecular targets. The main goal is to provide a basic understanding of fragmentation mechanisms and possible control schemes of benchmark systems such as H2+. This knowledge is further extended to more complex systems like the benchmark H3+ polyatomic and other molecules. In this dissertation, we report research based on two types of experiments. In the first part, we describe laser-induced fragmentation of molecular ion-beam targets. In the latter part, we discuss the formation of highly-excited neutral fragments from hydrogen molecules using ultrashort laser pulses. In carrying out these experiments, we have also extended experimental techniques beyond their previous capabilities. We have performed a few experiments to advance our understanding of laser-induced fragmentation of molecular-ion beams. For instance, we explored vibrationally resolved spectra of O2+ dissociation using various wavelengths. We observed a vibrational suppression

  11. 76 FR 52934 - Request for Comments: Public Input for the Launch of the Strong Cities, Strong Communities...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-24

    ... Economic Development Administration Request for Comments: Public Input for the Launch of the Strong Cities, Strong Communities Visioning Challenge AGENCY: Economic Development Administration, U.S. Department of..., 2011, the Economic Development Administration (EDA) published a Federal Register notice...

  12. Excitation of strong Langmuir turbulence in the ionosphere: Comparison of theory and observations

    SciTech Connect

    DuBois, D.F. ); Hansen, A. ); Rose, H.A. ); Russell, D. )

    1993-07-01

    The predictions of models of strong Langmuir turbulence (SLT) are compared with recent space- and time-resolved radar observations of the power spectra of turbulence induced in the ionosphere by powerful high-frequency (HF) waves. Distinct signatures of caviton dynamics, not predicted by the weak turbulence approximation, are seen in the observations. An improved model of the low-frequency fluctuations for equal electron and ion temperatures is presented as well as a discussion of density profile modification by the induced turbulence.

  13. Air-sea interactions during strong winter extratropical storms

    USGS Publications Warehouse

    Nelson, Jill; He, Ruoying; Warner, John C.; Bane, John

    2014-01-01

    A high-resolution, regional coupled atmosphere–ocean model is used to investigate strong air–sea interactions during a rapidly developing extratropical cyclone (ETC) off the east coast of the USA. In this two-way coupled system, surface momentum and heat fluxes derived from the Weather Research and Forecasting model and sea surface temperature (SST) from the Regional Ocean Modeling System are exchanged via the Model Coupling Toolkit. Comparisons are made between the modeled and observed wind velocity, sea level pressure, 10 m air temperature, and sea surface temperature time series, as well as a comparison between the model and one glider transect. Vertical profiles of modeled air temperature and winds in the marine atmospheric boundary layer and temperature variations in the upper ocean during a 3-day storm period are examined at various cross-shelf transects along the eastern seaboard. It is found that the air–sea interactions near the Gulf Stream are important for generating and sustaining the ETC. In particular, locally enhanced winds over a warm sea (relative to the land temperature) induce large surface heat fluxes which cool the upper ocean by up to 2 °C, mainly during the cold air outbreak period after the storm passage. Detailed heat budget analyses show the ocean-to-atmosphere heat flux dominates the upper ocean heat content variations. Results clearly show that dynamic air–sea interactions affecting momentum and buoyancy flux exchanges in ETCs need to be resolved accurately in a coupled atmosphere–ocean modeling framework.

  14. Theory of strong-field attosecond transient absorption

    NASA Astrophysics Data System (ADS)

    Wu, Mengxi; Chen, Shaohao; Camp, Seth; Schafer, Kenneth J.; Gaarde, Mette B.

    2016-03-01

    Attosecond transient absorption is one of the promising new techniques being developed to exploit the availability of sub-femtosecond extreme ultraviolet (XUV) pulses to study the dynamics of the electron on its natural time scale. The temporal resolution in a transient absorption setup comes from the control of the relative delay and coherence between pump and probe pulses, while the spectral resolution comes from the characteristic width of the features that are being probed. In this review we focus on transient absorption scenarios where an attosecond pulse of XUV radiation creates a broadband excitation that is subsequently probed by a few cycle infrared (IR) laser. Because the attosecond XUV pulses are locked to the IR field cycle, the exchange of energy in the laser-matter interaction can be studied with unprecedented precision. We focus on the transient absorption by helium atoms of XUV radiation around the first ionization threshold, where we can simultaneoulsy solve the time-dependent Schrödinger equation for the single atom response and the Maxwell wave equation for the collective response of the nonlinear medium. We use a time-domain method that allows us to treat on an equal footing all the different linear and nonlinear processes by which the medium can exchange energy with the fields. We present several simple models, based on a few-level system interacting with a strong IR field, to explain many of the novel features found in attosecond transient absorption spectrograms. These include the presence of light-induced states, which demonstrate the ability to probe the dressed states of the atom. We also present a time-domain interpretation of the resonant pulse propagation features that appear in absorption spectra in dense, macroscopic media. We close by reviewing several recent experimental results that can be explained in terms of the models we discuss. Our aim is to present a road map for understanding future attosecond transient absorption

  15. Strong Costs and Benefits of Winter Acclimatization in Drosophila melanogaster.

    PubMed

    Schou, Mads Fristrup; Loeschcke, Volker; Kristensen, Torsten Nygaard

    2015-01-01

    Studies on thermal acclimation in insects are often performed on animals acclimated in the laboratory under conditions that are not ecologically relevant. Costs and benefits of acclimation responses under such conditions may not reflect costs and benefits in natural populations subjected to daily and seasonal temperature fluctuations. Here we estimated costs and benefits in thermal tolerance limits in relation to winter acclimatization of Drosophila melanogaster. We sampled flies from a natural habitat during winter in Denmark (field flies) and compared heat and cold tolerance of these to that of flies collected from the same natural population, but acclimated to 25 °C or 13 °C in the laboratory (laboratory flies). We further obtained thermal performance curves for egg-to-adult viability of field and laboratory (25 °C) flies, to estimate possible cross-generational effects of acclimation. We found much higher cold tolerance and a lowered heat tolerance in field flies compared to laboratory flies reared at 25 °C. Flies reared in the laboratory at 13 °C exhibited the same thermal cost-benefit relations as the winter acclimatized flies. We also found a cost of winter acclimatization in terms of decreased egg-to-adult viability at high temperatures of eggs laid by winter acclimatized flies. Based on our findings we suggest that winter acclimatization in nature can induce strong benefits in terms of increased cold tolerance. These benefits can be reproduced in the laboratory under ecologically relevant rearing and testing conditions, and should be incorporated in species distribution modelling. Winter acclimatization also leads to decreased heat tolerance. This may create a mismatch between acclimation responses and the thermal environment, e.g. if temperatures suddenly increase during spring, under current and expected more variable future climatic conditions.

  16. Frequency-dependent effective hydraulic conductivity of strongly heterogeneous media.

    PubMed

    Caspari, E; Gurevich, B; Müller, T M

    2013-10-01

    The determination of the transport properties of heterogeneous porous rocks, such as an effective hydraulic conductivity, arises in a range of geoscience problems, from groundwater flow analysis to hydrocarbon reservoir modeling. In the presence of formation-scale heterogeneities, nonstationary flows, induced by pumping tests or propagating elastic waves, entail localized pressure diffusion processes with a characteristic frequency depending on the pressure diffusivity and size of the heterogeneity. Then, on a macroscale, a homogeneous equivalent medium exists, which has a frequency-dependent effective conductivity. The frequency dependence of the conductivity can be analyzed with Biot's equations of poroelasticity. In the quasistatic frequency regime of this framework, the slow compressional wave is a proxy for pressure diffusion processes. This slow compressional wave is associated with the out-of-phase motion of the fluid and solid phase, thereby creating a relative fluid-solid displacement vector field. Decoupling of the poroelasticity equations gives a diffusion equation for the fluid-solid displacement field valid in a poroelastic medium with spatial fluctuations in hydraulic conductivity. Then, an effective conductivity is found by a Green's function approach followed by a strong-contrast perturbation theory suggested earlier in the context of random dielectrics. This theory leads to closed-form expressions for the frequency-dependent effective conductivity as a function of the one- and two-point probability functions of the conductivity fluctuations. In one dimension, these expressions are consistent with exact solutions in both low- and high-frequency limits for arbitrary conductivity contrast. In 3D, the low-frequency limit depends on the details of the microstructure. However, the derived approximation for the effective conductivity is consistent with the Hashin-Shtrikman bounds.

  17. Field Effect and Strongly Localized Carriers in the Metal-Insulator Transition Material VO(2).

    PubMed

    Martens, K; Jeong, J W; Aetukuri, N; Rettner, C; Shukla, N; Freeman, E; Esfahani, D N; Peeters, F M; Topuria, T; Rice, P M; Volodin, A; Douhard, B; Vandervorst, W; Samant, M G; Datta, S; Parkin, S S P

    2015-11-06

    The intrinsic field effect, the change in surface conductance with an applied transverse electric field, of prototypal strongly correlated VO(2) has remained elusive. Here we report its measurement enabled by epitaxial VO(2) and atomic layer deposited high-κ dielectrics. Oxygen migration, joule heating, and the linked field-induced phase transition are precluded. The field effect can be understood in terms of field-induced carriers with densities up to ∼5×10(13)  cm(-2) which are trongly localized, as shown by their low, thermally activated mobility (∼1×10(-3)  cm(2)/V s at 300 K). These carriers show behavior consistent with that of Holstein polarons and strongly impact the (opto)electronics of VO(2).

  18. Review fifteen years of search for strong nucleosomes.

    PubMed

    Trifonov, Edward N; Nibhani, Reshma

    2015-08-01

    Don Crothers, Mikael Kubista, Jon Widom, and their teams have been first to look for strong nucleosomes, in a bid to reveal the nucleosome positioning pattern(s) carried by the nucleosome DNA sequences. They were first to demonstrate that the nucleosome stability correlates with 10-11 base sequence periodicity, and that the strong nucleosomes localize preferentially in centromeres. This review describes these findings and their connection to recent discovery of the strong nucleosomes (SNs) with visibly periodic nucleosome DNA sequences.

  19. A brief introduction to the strong CP problem

    SciTech Connect

    Wu, Dan-di Melbourne Univ., Parkville . School of Physics)

    1991-09-01

    The present status of the strong CP problem is briefly reviewed in a heuristic way. A crisis in EDMN calculation is explained. The equation of vacuum alignment obtained by the author and collaborators last year put a constraint on strong CP parameters. Thus the strong CP will be forced to vanish in one of the three scenarios characterized by axion, zero quark mass, and vanishing quark condensate. 12 refs.

  20. Suppression of Rayleigh Taylor instability in strongly coupled plasmas

    SciTech Connect

    Das, Amita; Kaw, Predhiman

    2014-06-15

    The Rayleigh Taylor instability in a strongly coupled plasma medium has been investigated using the equations of generalized hydrodynamics. It is demonstrated that the visco-elasticity of the strongly coupled medium due to strong inter particle correlations leads to a suppression of the Rayleigh Taylor instability unless certain threshold conditions are met. The relevance of these results to experiments on laser compression of matter to high densities including those related to inertial confinement fusion using lasers has also been shown.