WorldWideScience

Sample records for strong interhemispheric transport

  1. Experimental evidence of interhemispheric transport from airborne carbon monoxide measurements

    Science.gov (United States)

    Newell, R. E.; Gauntner, D. J.

    1979-01-01

    During the period 28-30 October 1977, a Pan American 747-SP aircraft flew around the world with an automated instrument package that included measurements of atmospheric CO made every 4 sec. The flight path extended from San Francisco, over the North Pole to London, south to Capetown, over the South Pole to Auckland, and back to San Francisco. The data collected show large changes with longitude, which are interpreted as direct evidence of interhemispheric mixing. Possible sources for CO are discussed.

  2. The role of monsoon-like zonally asymmetric heating in interhemispheric transport

    Science.gov (United States)

    Chen, Gang; Orbe, Clara; Waugh, Darryn

    2017-03-01

    While the importance of the seasonal migration of the zonally averaged Hadley circulation on interhemispheric transport of trace gases has been recognized, few studies have examined the role of the zonally asymmetric monsoonal circulation. This study investigates the role of monsoon-like zonally asymmetric heating on interhemispheric transport using a dry atmospheric model that is forced by idealized Newtonian relaxation to a prescribed radiative equilibrium temperature. When only the seasonal cycle of zonally symmetric heating is considered, the mean age of air in the Southern Hemisphere since last contact with the Northern Hemisphere midlatitude boundary layer is much larger than the observations. The introduction of monsoon-like zonally asymmetric heating not only reduces the mean age of tropospheric air to more realistic values but also produces an upper tropospheric cross-equatorial transport pathway in boreal summer that resembles the transport pathway simulated in the NASA Global Modeling Initiative Chemistry Transport Model driven with Modern-Era Retrospective Analysis for Research and Applications meteorological fields. These results highlight that the monsoon-induced eddy circulation plays an important role in the interhemispheric transport of long-lived chemical constituents.

  3. Atmospheric mercury in the Southern Hemisphere tropics: seasonal and diurnal variations and influence of inter-hemispheric transport

    Directory of Open Access Journals (Sweden)

    D. Howard

    2017-09-01

    Full Text Available Mercury is a toxic element of serious concern for human and environmental health. Understanding its natural cycling in the environment is an important goal towards assessing its impacts and the effectiveness of mitigation strategies. Due to the unique chemical and physical properties of mercury, the atmosphere is the dominant transport pathway for this heavy metal, with the consequence that regions far removed from sources can be impacted. However, there exists a dearth of long-term monitoring of atmospheric mercury, particularly in the tropics and Southern Hemisphere. This paper presents the first 2 years of gaseous elemental mercury (GEM measurements taken at the Australian Tropical Atmospheric Research Station (ATARS in northern Australia, as part of the Global Mercury Observation System (GMOS. Annual mean GEM concentrations determined at ATARS (0.95 ± 0.12 ng m−3 are consistent with recent observations at other sites in the Southern Hemisphere. Comparison with GEM data from other Australian monitoring sites suggests a concentration gradient that decreases with increasing latitude. Seasonal analysis shows that GEM concentrations at ATARS are significantly lower in the distinct wet monsoon season than in the dry season. This result provides insight into alterations of natural mercury cycling processes as a result of changes in atmospheric humidity, oceanic/terrestrial fetch, and convective mixing, and invites future investigation using wet mercury deposition measurements. Due to its location relative to the atmospheric equator, ATARS intermittently samples air originating from the Northern Hemisphere, allowing an opportunity to gain greater understanding of inter-hemispheric transport of mercury and other atmospheric species. Diurnal cycles of GEM at ATARS show distinct nocturnal depletion events that are attributed to dry deposition under stable boundary layer conditions. These cycles provide strong further evidence supportive of

  4. Atmospheric mercury in the Southern Hemisphere tropics: seasonal and diurnal variations and influence of inter-hemispheric transport

    Science.gov (United States)

    Howard, Dean; Nelson, Peter F.; Edwards, Grant C.; Morrison, Anthony L.; Fisher, Jenny A.; Ward, Jason; Harnwell, James; van der Schoot, Marcel; Atkinson, Brad; Chambers, Scott D.; Griffiths, Alan D.; Werczynski, Sylvester; Williams, Alastair G.

    2017-09-01

    Mercury is a toxic element of serious concern for human and environmental health. Understanding its natural cycling in the environment is an important goal towards assessing its impacts and the effectiveness of mitigation strategies. Due to the unique chemical and physical properties of mercury, the atmosphere is the dominant transport pathway for this heavy metal, with the consequence that regions far removed from sources can be impacted. However, there exists a dearth of long-term monitoring of atmospheric mercury, particularly in the tropics and Southern Hemisphere. This paper presents the first 2 years of gaseous elemental mercury (GEM) measurements taken at the Australian Tropical Atmospheric Research Station (ATARS) in northern Australia, as part of the Global Mercury Observation System (GMOS). Annual mean GEM concentrations determined at ATARS (0.95 ± 0.12 ng m-3) are consistent with recent observations at other sites in the Southern Hemisphere. Comparison with GEM data from other Australian monitoring sites suggests a concentration gradient that decreases with increasing latitude. Seasonal analysis shows that GEM concentrations at ATARS are significantly lower in the distinct wet monsoon season than in the dry season. This result provides insight into alterations of natural mercury cycling processes as a result of changes in atmospheric humidity, oceanic/terrestrial fetch, and convective mixing, and invites future investigation using wet mercury deposition measurements. Due to its location relative to the atmospheric equator, ATARS intermittently samples air originating from the Northern Hemisphere, allowing an opportunity to gain greater understanding of inter-hemispheric transport of mercury and other atmospheric species. Diurnal cycles of GEM at ATARS show distinct nocturnal depletion events that are attributed to dry deposition under stable boundary layer conditions. These cycles provide strong further evidence supportive of a multi-hop model of GEM

  5. Interhemispheric Asymmetry of the Sunward Plasma Flows for Strongly Dominant IMF BZ > 0

    Science.gov (United States)

    Yakymenko, K. N.; Koustov, A. V.; Fiori, R. A. D.

    2018-01-01

    Super Dual Auroral Radar Network (SuperDARN) convection maps obtained simultaneously in both hemispheres are averaged to infer polar cap ionospheric flow patterns under strongly dominant positive interplanetary magnetic field (IMF) Bz component. The data set consisted of winter observations in the Northern Hemisphere simultaneously with summer observations in the Southern Hemisphere. Long-lasting high-latitude dayside reverse convection cells are shown to have faster sunward flows at near-magnetic noon hours in the summer/Southern Hemisphere. Sunward flows typically deviate from the midnight-noon meridian toward 10-11 h of magnetic local time in the summer/Southern Hemisphere and are more aligned with the midnight-noon meridian in the winter/Northern Hemisphere. Flow deviations in the winter/Northern Hemisphere can be both toward prenoon and postnoon hours, and there is no clear relationship between flow deviation and the IMF By component. No strong preference for the sunward flow occurrence depending on the IMF Bx polarity was found. In addition, the rate of the sunward flow speed increase in response to an increase in driving conditions was found to be comparable for the IMF Bx > 0 and Bx < 0.

  6. Transport phenomena in strongly correlated Fermi liquids

    Energy Technology Data Exchange (ETDEWEB)

    Kontani, Hiroshi [Nagoya Univ., Aichi (Japan). Dept. of Physics

    2013-03-01

    Comprehensive overview. Written by an expert of this topic. Provides the reader with current developments in the field. In conventional metals, various transport coefficients are scaled according to the quasiparticle relaxation time, {tau}, which implies that the relaxation time approximation (RTA) holds well. However, such a simple scaling does not hold in many strongly correlated electron systems, reflecting their unique electronic states. The most famous example would be cuprate high-Tc superconductors (HTSCs), where almost all the transport coefficients exhibit a significant deviation from the RTA results. To better understand the origin of this discrepancy, we develop a method for calculating various transport coefficients beyond the RTA by employing field theoretical techniques. Near the magnetic quantum critical point, the current vertex correction (CVC), which describes the electron-electron scattering beyond the relaxation time approximation, gives rise to various anomalous transport phenomena. We explain anomalous transport phenomena in cuprate HTSCs and other metals near their magnetic or orbital quantum critical point using a uniform approach. We also discuss spin related transport phenomena in strongly correlated systems. In many d- and f-electron systems, the spin current induced by the spin Hall effect is considerably greater because of the orbital degrees of freedom. This fact attracts much attention due to its potential application in spintronics. We discuss various novel charge, spin and heat transport phenomena in strongly correlated metals.

  7. Transport phenomena in strongly correlated Fermi liquids

    CERN Document Server

    Kontani, Hiroshi

    2013-01-01

    In conventional metals, various transport coefficients are scaled according to the quasiparticle relaxation time, \\tau, which implies that the relaxation time approximation (RTA) holds well. However, such a simple scaling does not hold in many strongly correlated electron systems, reflecting their unique electronic states. The most famous example would be cuprate high-Tc superconductors (HTSCs), where almost all the transport coefficients exhibit a significant deviation from the RTA results. To better understand the origin of this discrepancy, we develop a method for calculating various transport coefficients beyond the RTA by employing field theoretical techniques. Near the magnetic quantum critical point, the current vertex correction (CVC), which describes the electron-electron scattering beyond the relaxation time approximation, gives rise to various anomalous transport phenomena. We explain anomalous transport phenomena in cuprate HTSCs and other metals near their magnetic or orbital quantum critical poi...

  8. Dreaming, handedness, and sleep architecture: interhemispheric mechanisms.

    Science.gov (United States)

    Christman, Stephen D; Propper, Ruth E

    2010-01-01

    Research on individual differences in sleep as a function of handedness is reviewed. Special emphasis is placed on a new way of approaching handedness in terms of degree (strong/consistent versus mixed/inconsistent), as opposed to the traditional focus on direction (right versus left). Handedness differences in sleep architecture reflect increased time in REM sleep and decreased time in NREM sleep in consistent right-handers. A framework relating increased interhemispheric interaction in mixed-handers, increased interhemispheric interaction during episodic retrieval, increased interhemispheric interaction during NREM sleep, and the role of NREM sleep in memory consolidation is discussed. Copyright © 2010 Elsevier Inc. All rights reserved.

  9. Quantum Transport in Strongly Correlated Systems

    DEFF Research Database (Denmark)

    Bohr, Dan

    2007-01-01

    the density matrix renormalization group (DMRG) method. We present two DMRG setups for calculating the linear conductance of strongly correlated nanostructures in the infinitesimal source-drain voltage regime. The first setup describes the leads by modified real-space tight-binding chains, whereas the second...... screening plays a much less significant role than in bulk systems due to the reduced size of the objects, therefore making it necessary to consider the importance of correlations between electrons. The work presented in this thesis deals with quantum transport through strongly correlated systems using....... Thus both coherence and correlation effects are important in this model, and the methods applied should be able to handle both these effects rigorously. We present the DMRG setup for this model and benchmark against existing Greens function results for the model. Then we present initial DMRG results...

  10. TRANSPORT PROPERTIES OF THE STRONGLY CORRELATED SYSTEMS

    Directory of Open Access Journals (Sweden)

    T.Domanski

    2004-01-01

    Full Text Available The transport properties of various systems are studied here in the context of three different models. These are: - the disordered Hubbard model applicable to correlated binary alloys with a general disorder, - the Anderson model used in describing the Kondo physics of a quantum dot connected to the external superconducting leads, and - the Ranninger-Robaszkiewicz model applied to the study of optical properties of the system with preformed electron pairs above the temperature of transition to the superconducting state. We calculate the density of states, specific heat, the Wilson ratio and conductivity of the correlated binary alloy with off-diagonal disorder. We investigate the conditions under which the Kondo peak appears in the density of states and in the conductance of a dot coupled to the external superconducting leads. We analyze the effect of the pseudogap on the optical spectra in the high temperature superconductors described by the boson-fermion model.

  11. Anomalous transport phenomena in Fermi liquids with strong magnetic fluctuations

    Energy Technology Data Exchange (ETDEWEB)

    Kontani, Hiroshi [Department of Physics, Nagoya University, Nagoya 464-8602 (Japan)

    2008-02-15

    In this paper, we present recent developments in the theory of transport phenomena based on the Fermi liquid theory. In conventional metals, various transport coefficients are scaled according to the quasiparticles relaxation time, {tau}, which implies that the relaxation time approximation (RTA) holds well. However, such a simple scaling does not hold in many strongly correlated electron systems. The most famous example would be high-T{sub c} superconductors (HTSCs), where almost all the transport coefficients exhibit a significant deviation from the RTA results. This issue has been one of the most significant unresolved problems in HTSCs for a long time. Similar anomalous transport phenomena have been observed in metals near their antiferromagnetic (AF) quantum critical point (QCP). The main goal of this study is to demonstrate whether the anomalous transport phenomena in HTSC is evidence of a non-Fermi liquid ground state, or just RTA violation in strongly correlated Fermi liquids. Another goal is to establish a unified theory of anomalous transport phenomena in metals with strong magnetic fluctuations. For these purposes, we develop a method for calculating various transport coefficients beyond the RTA by employing field theoretical techniques. In a Fermi liquid, an excited quasiparticle induces other excited quasiparticles by collision, and current due to these excitations is called a current vertex correction (CVC). Landau noticed the existence of CVC first, which is indispensable for calculating transport coefficients in accord with the conservation laws. Here, we develop a transport theory involving resistivity and the Hall coefficient on the basis of the microscopic Fermi liquid theory, by considering the CVC. In nearly AF Fermi liquids, we find that the strong backward scattering due to AF fluctuations induces the CVC with prominent momentum dependence. This feature of the CVC can account for the significant enhancement in the Hall coefficient

  12. Anomalous transport phenomena in Fermi liquids with strong magnetic fluctuations

    International Nuclear Information System (INIS)

    Kontani, Hiroshi

    2008-01-01

    In this paper, we present recent developments in the theory of transport phenomena based on the Fermi liquid theory. In conventional metals, various transport coefficients are scaled according to the quasiparticles relaxation time, τ, which implies that the relaxation time approximation (RTA) holds well. However, such a simple scaling does not hold in many strongly correlated electron systems. The most famous example would be high-T c superconductors (HTSCs), where almost all the transport coefficients exhibit a significant deviation from the RTA results. This issue has been one of the most significant unresolved problems in HTSCs for a long time. Similar anomalous transport phenomena have been observed in metals near their antiferromagnetic (AF) quantum critical point (QCP). The main goal of this study is to demonstrate whether the anomalous transport phenomena in HTSC is evidence of a non-Fermi liquid ground state, or just RTA violation in strongly correlated Fermi liquids. Another goal is to establish a unified theory of anomalous transport phenomena in metals with strong magnetic fluctuations. For these purposes, we develop a method for calculating various transport coefficients beyond the RTA by employing field theoretical techniques. In a Fermi liquid, an excited quasiparticle induces other excited quasiparticles by collision, and current due to these excitations is called a current vertex correction (CVC). Landau noticed the existence of CVC first, which is indispensable for calculating transport coefficients in accord with the conservation laws. Here, we develop a transport theory involving resistivity and the Hall coefficient on the basis of the microscopic Fermi liquid theory, by considering the CVC. In nearly AF Fermi liquids, we find that the strong backward scattering due to AF fluctuations induces the CVC with prominent momentum dependence. This feature of the CVC can account for the significant enhancement in the Hall coefficient, magnetoresistance

  13. Transport Theory for Plasmas that are Strongly Magnetized and Strongly Coupled

    Science.gov (United States)

    Baalrud, Scott; Daligault, Jerome

    2016-10-01

    Plasmas with components that are magnetized, strongly coupled, or both arise in a variety of frontier plasma physics experiments including magnetized dusty plasmas, nonneutral plasmas, magnetized ICF concepts, as well as from self-generated fields in ICF. Here, a species is considered strongly magnetized if the gyroradius is smaller than the spatial scale over which Coulomb interactions occur. A theory for transport properties is described that treats a wide range of both coupling and magnetization strengths. The approach is based on an extension of the recent effective potential transport theory to include a strong magnetic field. The underlying kinetic theory is based on an extension of the Boltzmann equation to include a strong magnetic field in the dynamics of binary scattering events. Corresponding magnetohydrodynamic equations are derived by solving the kinetic equation using a Chapman-Enskog like spectral method. Results are compared with classical molecular dynamics simulations of self-diffusion of the one component plasmas, and with simulations of parallel to perpendicular temperature equilibration of an initially anisotropic distribution. This material is based upon work supported by AFOSR Award FA9550-16-1-0221 and DOE OFES Award DE-SC0016159.

  14. Quantum Thermodynamics in Strong Coupling: Heat Transport and Refrigeration

    Directory of Open Access Journals (Sweden)

    Gil Katz

    2016-05-01

    Full Text Available The performance characteristics of a heat rectifier and a heat pump are studied in a non-Markovian framework. The device is constructed from a molecule connected to a hot and cold reservoir. The heat baths are modelled using the stochastic surrogate Hamiltonian method. The molecule is modelled by an asymmetric double-well potential. Each well is semi-locally connected to a heat bath composed of spins. The dynamics are driven by a combined system–bath Hamiltonian. The temperature of the baths is regulated by a secondary spin bath composed of identical spins in thermal equilibrium. A random swap operation exchange spins between the primary and secondary baths. The combined system is studied in various system–bath coupling strengths. In all cases, the average heat current always flows from the hot towards the cold bath in accordance with the second law of thermodynamics. The asymmetry of the double well generates a rectifying effect, meaning that when the left and right baths are exchanged the heat current follows the hot-to-cold direction. The heat current is larger when the high frequency is coupled to the hot bath. Adding an external driving field can reverse the transport direction. Such a refrigeration effect is modelled by a periodic driving field in resonance with the frequency difference of the two potential wells. A minimal driving amplitude is required to overcome the heat leak effect. In the strong driving regime the cooling power is non-monotonic with the system–bath coupling.

  15. ABC transporter research: going strong 40 years on.

    Science.gov (United States)

    Theodoulou, Frederica L; Kerr, Ian D

    2015-10-01

    In most organisms, ABC transporters constitute one of the largest families of membrane proteins. In humans, their functions are diverse and underpin numerous key physiological processes, as well as being causative factors in a number of clinically relevant pathologies. Advances in our understanding of these diseases have come about through combinations of genetic and protein biochemical investigations of these transporters and the power of in vitro and in vivo investigations is helping to develop genotype-phenotype understanding. However, the importance of ABC transporter research goes far beyond human biology; microbial ABC transporters are of great interest in terms of understanding virulence and drug resistance and industrial biotechnology researchers are exploring the potential of prokaryotic ABC exporters to increase the capacity of synthetic biology systems. Plant ABC transporters play important roles in transport of hormones, xenobiotics, metals and secondary metabolites, pathogen responses and numerous aspects of development, all of which are important in the global food security area. For 3 days in Chester, this Biochemical Society Focused Meeting brought together researchers with diverse experimental approaches and with different fundamental questions, all of which are linked by the commonality of ABC transporters. © 2015 Authors.

  16. Measurements of strong correlations in the transport of light through strongly scattering materials

    NARCIS (Netherlands)

    Akbulut, D.

    2013-01-01

    In this thesis, we study light transport through multiple scattering random photonic materials. Light incident on such materials undergoes many scattering events before exiting the material. The relation between the incident and the transmitted fields is determined by the optical transmission matrix

  17. Elevated Tropospheric Ozone Over the South Tropical Atlantic in January-February 1999: An Ozone Paradox Due to Interhemispheric Transport, Lightning, or Stratospheric Exchange?

    Science.gov (United States)

    Thompson, Anne M.; Doddridge, Bruce G.; Witte, Jacquelyn C.; Hudson, Robert D.; Luke, Winston T.; Johnson, James E.; Johnson, Bryan J.; Oltmans, Samuel J.; Einaudi, Franco (Technical Monitor)

    2000-01-01

    On this first North American to southern African oceanographic cruise with ozonesonde launches (January and February 1999 on board the NOAA Research Vessel Ronald H Brown between Norfolk, VA, and Cape Town, South Africa) we found: (1) high ozone, CO, and aerosols off northern equatorial Africa from biomass burning, but even higher ozone concentrations off southern Africa which was not burning - an "ozone paradox"; (2) TOMS satellite evidence that south Atlantic elevated ozone in January-February 1999 was a regional feature similar in extent to the well-known September-October ozone maximum. Several mechanisms are considered to explain the "ozone paradox." Convection transporting air from the lower troposphere rich in ozone and/or ozone precursors to the upper troposphere through the ITCZ (intertropical Convergence Zone) may lead to cross-hemisphere transport of pollution. This is supported by trajectory linkage of lower-tropospheric ozone maxima with smoke seen by the TOMS satellite. Lightning-generated NO (nitric oxide) leading to ozone peaks of > 100 ppbv observed at 7-10 km altitude is another explanation. The TRMM (Tropical Rainfall Measuring Mission) Lightning Imaging Sounder shows many lightning flashes over southern Africa, which trajectories link to the high-ozone layers south of the ITCZ. The highest ozone peaks in the middle troposphere correspond to very low water vapor, which may point to photochemical destruction of ozone or subsidence from the upper troposphere which had interacted with stratospheric ozone.

  18. Interhemispheric integration in visual search.

    Science.gov (United States)

    Shipp, Stewart

    2011-07-01

    The search task of Luck, Hillyard, Mangun and Gazzaniga (1989) was optimised to test for the presence of a bilateral field advantage in the visual search capabilities of normal subjects. The modified design used geometrically regular arrays of 2, 4 or 8 items restricted to hemifields delineated by the vertical or horizontal meridian; the target, if present, appeared at one of two fixed positions per quadrant at an eccentricity of 11 deg. Group and individual performance data were analysed in terms of the slope of response time against display-size functions ('RT slope'). Averaging performance across all conditions save display mode (bilateral vs. unilateral) revealed a significant bilateral advantage in the form of a 21% increase in apparent item scanning speed for target detection; in the absence of a target, bilateral displays gave a 5% increase in speed that was not significant. Factor analysis by ANOVA confirmed this main effect of display mode, and also revealed several higher order interactions with display geometry, indicating that the bilateral advantage was masked at certain target positions by a crowding-like effect. In a numerical model of search efficiency (i.e. RT slope), bilateral advantage was parameterised by an interhemispheric 'transfer factor' (T) that governs the strength of the ipsilateral representation of distractors, and modifies the level of intrahemispheric competition with the target. The factor T was found to be higher in superior field than inferior field; this result held for the modelled data of each individual subject, as well as the group, representing a uniform tendency for the bilateral advantage to be more prominent in inferior field. In fact statistical analysis and modelling of search efficiency showed that the geometrical display factors (target polar and quadrantic location, and associated crowding effects) were all remarkably consistent across subjects. Greater variability was inferred within a fixed, decisional component of

  19. Abnormal interhemispheric connectivity in male psychopathic offenders.

    Science.gov (United States)

    Hoppenbrouwers, Sylco S; De Jesus, Danilo R; Sun, Yinming; Stirpe, Tania; Hofman, Dennis; McMaster, Jeff; Hughes, Ginny; Daskalakis, Zafiris J; Schutter, Dennis J L G

    2014-01-01

    Psychopathic offenders inevitably violate interpersonal norms and frequently resort to aggressive and criminal behaviour. The affective and cognitive deficits underlying these behaviours have been linked to abnormalities in functional interhemispheric connectivity. However, direct neurophysiological evidence for dysfunctional connectivity in psychopathic offenders is lacking. We used transcranial magnetic stimulation combined with electroencephalography to examine interhemispheric connectivity in the dorsolateral and motor cortex in a sample of psychopathic offenders and healthy controls. We also measured intracortical inhibition and facilitation over the left and right motor cortex to investigate the effects of local cortical processes on interhemispheric connectivity. We enrolled 17 psychopathic offenders and 14 controls in our study. Global abnormalities in right to left functional connectivity were observed in psychopathic offenders compared with controls. Furthermore, in contrast to controls, psychopathic offenders showed increased intracortical inhibition in the right, but not the left, hemisphere. The relatively small sample size limited the sensitivity to show that the abnormalities in interhemispheric connectivity were specifically related to the dorsolateral prefrontal cortex in psychopathic offenders. To our knowledge, this study provides the first neurophysiological evidence for abnormal interhemispheric connectivity in psychopathic offenders and may further our understanding of the disruptive antisocial behaviour of these offenders.

  20. Tuberculosis meningitis presenting as isolated interhemispheric exudates

    International Nuclear Information System (INIS)

    Bharath, R.D.; Vasudev, M.K.; Sinha, S.; Ravishankar, S.; Chandrashekar, N.

    2008-01-01

    Full text: The total number of tuberculosis cases in the world is increasing, and less common forms of tuberculous meningitis (TBM) with varying imaging manifestations are being encountered more often. We describe anterior interhemispheric variety of TBM, which has not been previously described to the best of our knowledge in the literature. Common imaging findings in these five patients include predominant involvement of the meninges in the anterior interhemispheric fissure with relatively little enhancement of the basal cisterns. Knowledge of uncommon radiological findings is vital in early diagnosis and treatment of this common disease.

  1. Analytical modeling of light transport in scattering materials with strong absorption

    NARCIS (Netherlands)

    Meretska, M. L.; Uppu, R.; Vissenberg, Gilles; Lagendijk, A.; Ijzerman, W. L.; Vos, W. L.

    2017-01-01

    We have investigated the transport of light through slabs that both scatter and strongly absorb, a situation that occurs in diverse application fields ranging from biomedical optics, powder technology, to solid-state lighting. In particular, we study the transport of light in the visible wavelength

  2. Anterior Interhemispheric Approach for Olfactory Groove Meningioma

    Directory of Open Access Journals (Sweden)

    Imam Hidayat

    2016-09-01

    Full Text Available Objective: To evaluate the surgical technique with bifrontal interhemispheric approach for total removal of tumor in olfactory groove meningioma (OGM. Methods: This study described a case of a 38-year-old woman with bilateral blindness, anosmia, and behaviour changes. Imaging studies show a tumor mass in midfrontal base. Surgery using a bifrontal interhemispheric approach was performed and total removal was achieved and postoperative computed tomography (CT scan was performed to confirm the result. Histopathological findings established a diagnosis of meningioma. Results: A coronal skin incision behind the hairline was utilized. The scalp was elevated, taking care to reserve the vascularized pericranium medial to the linea temporalis of each side, and preserving the 2 supraorbital nerves. Eight burr holes were used, with the two initial holes made on each side of the orbitotemporal region, and the other four holes at the midline. A bifrontal craniotomy was performed. The tumor was first detached from its attachment with bipolar cautery and debulked. During this step, the main tumor feeder arteries from the anterior and posterior ethmoidal artery were interrupted, and the tumor devascularized. Total tumor removal through surgical intervention was achieved and confirmed by head CT-scan postoperatively. Conclusions: This case report supports the suitability of the bifrontal interhemispheric approach for OGM resection with additional radiation therapy.

  3. A new approach to tracer transport analysis: From fracture systems to strongly heterogeneous porous media

    International Nuclear Information System (INIS)

    Tsang, Chin-Fu.

    1989-02-01

    Many current development and utilization of groundwater resources include a study of their flow and transport properties. These properties are needed in evaluating possible changes in groundwater quality and potential transport of hazardous solutes through the groundwater system. Investigation of transport properties of fractured rocks is an active area of research. Most of the current approaches to the study of flow and transport in fractured rocks cannot be easily used for analysis of tracer transport field data. A new approach is proposed based on a detailed study of transport through a fracture of variable aperture. This is a two-dimensional strongly heterogeneous permeable system. It is suggested that tracer breakthrough curves can be analyzed based on an aperture or permeability probability distribution function that characterizes the tracer flow through the fracture. The results are extended to a multi-fracture system and can be equally applied to a strongly heterogeneous porous medium. Finally, the need for multi-point or line and areal tracer injection and observation tests is indicated as a way to avoid the sensitive dependence of point measurements on local permeability variability. 30 refs., 15 figs

  4. Stability of the interhemispheric thermohaline circulation in a coupled box model

    Science.gov (United States)

    Stone, Peter H.; Krasovskiy, Yuriy P.

    1999-07-01

    The coupled atmosphere-ocean box model of the interhemispheric thermohaline circulation (THC) formulated by Scott et al. [Scott, J.R., Marotzke, J., Stone, P.H., 1999. Interhemispheric THC in a coupled box model. J. Phys. Oceanogr., 29, 351-365.] is solved analytically, by introducing the approximation that the time variations of salinity in the ocean are much slower than the time variations in the temperature. The analytic solution shows that there is an unstable limit cycle near the bifurcation where the flow becomes unstable, as suggested by Scott et al.'s numerical solutions. The solution also leads to an analytic expression for the conditions under which the instability discovered by Scott et al. sets in, which is more general than that found by Scott et al. In particular, it includes the effect of coupling the THC to the atmospheric meridional transports of heat and moisture. It shows that the stability of THC is much more sensitive to the representation of the atmospheric heat transport, i.e., to how it depends on the meridional temperature gradient, than it is in hemispheric models. In particular, it shows that interhemispheric ocean models that use mixed boundary conditions, or couple the ocean to a diffusive representation of the atmospheric heat transport, are less susceptible to this kind of instability than when the ocean is coupled to a representation of the atmospheric meridional heat transport which is more sensitive to the meridional temperature gradient, as is implied by observations and theory.

  5. Limiting and Fedosov's Currents of a Strongly Magnetized Electron Beam in Asymmetric Transportation Channels

    Science.gov (United States)

    Goikhman, M. B.; Gromov, A. V.; Kovalev, N. F.; V. Palitsin, A.

    2016-12-01

    We consider the properties of thin-walled, strongly magnetized electron beams in closed evacuated transportation channels with arbitrary cross sections of the channel and the electron beam. Explicit precise formulas are obtained for the limiting and Fedosov's currents of such electron beams. The found relationships allow one to explain many observed phenomena and can serve as a basis for verification of the results of more complicated calculations.

  6. Observation of quantum-limited spin transport in strongly interacting two-dimensional Fermi gases

    Science.gov (United States)

    Olsen, Ben A.; Luciuk, Chris; Smale, Scott; Böttcher, Florian; Sharum, Haille; Trotzky, Stefan; Enss, Tilman; Thywissen, Joseph H.

    2017-04-01

    Conjectured quantum bounds on transport appear to be respected in many strongly interacting many-body systems. Since transport occurs as a system relaxes to equilibrium, many such bounds can be recast as an upper bound on the local relaxation rate kB T / ℏ . Systems saturating this ``Planckian'' bound lack well defined quasiparticles promoting transport. We measure the transport properties of 2D ultracold Fermi gases of 40K during transverse demagnetization in a magnetic field gradient. Using a phase-coherent spin-echo sequence, we distinguish bare spin diffusion from the Leggett-Rice effect, in which demagnetization is slowed by the precession of spin current around the local magnetization. When the 2D scattering length is tuned near an s-wave Feshbach resonance to be comparable to the inverse Fermi wave vector kF- 1 , we find that the bare transverse spin diffusivity reaches a minimum of 1 . 7(6) ℏ / m . Demagnetization is also reflected in the growth rate of the s-wave contact, observed using time-resolved rf spectroscopy. At unitarity, the contact rises to 0 . 28(3) kF2 per particle, measuring the breaking of scaling symmetry. Our observations support the conjecture that under strong scattering, the local relaxation rate is bounded from above by kB T / ℏ .

  7. Integrated electronic transport and thermometry at milliKelvin temperatures and in strong magnetic fields.

    Science.gov (United States)

    Samkharadze, N; Kumar, A; Manfra, M J; Pfeiffer, L N; West, K W; Csáthy, G A

    2011-05-01

    We fabricated a He-3 immersion cell for transport measurements of semiconductor nanostructures at ultra low temperatures and in strong magnetic fields. We have a new scheme of field-independent thermometry based on quartz tuning fork Helium-3 viscometry which monitors the local temperature of the sample's environment in real time. The operation and measurement circuitry of the quartz viscometer is described in detail. We provide evidence that the temperature of two-dimensional electron gas confined to a GaAs quantum well follows the temperature of the quartz viscometer down to 4 mK.

  8. Interhemispheric cortical connections and time perception: A case study with agenesis of the corpus callosum.

    Science.gov (United States)

    Okajima, Miku; Futamura, Akinori; Honma, Motoyasu; Kawamura, Mitsuru; Yotsumoto, Yuko

    2017-10-01

    In daily life, we sometimes select temporal cues of one sort while suppressing others. This study investigated the mechanism of suppression by examining a split-brain patient's perception of target intervals while ignoring distractor intervals. A patient with agenesis of corpus callosum and five age- and sex-matched control subjects participated in reproduction of target intervals while ignoring distractors displayed in the visual field either ipsilateral or contralateral to target. In the patient, the distractor interfered with reproduction performance more strongly when contralateral rather than ipsilateral. Our results suggest that the corpus callosum plays an inhibitory role in interhemispheric interference and that temporal interval information can be transferred via subcortical structures when there are no direct interhemispheric pathways. Copyright © 2017. Published by Elsevier Inc.

  9. Experimental study of transport of relativistic electron beams in strong magnetic mirror field

    Science.gov (United States)

    Sakata, Shohei; Kondo, Kotaro; Bailly-Grandvaux, Mathiu; Bellei, Claudio; Santos, Joao; Firex Project Team

    2015-11-01

    Relativistic electron beams REB produced by ultra high intense laser pulses have generally a large divergence angle that results in degradation of energy coupling between the REB and a fuel core in the fast ignition scheme. Guiding and focusing of the REB by a strong external magnetic field was proposed to achieve high efficiency. We investigated REB transport through 50 μm or 250 μm thick plastic foils CuI doped under external magnetic fields, in magnetic mirror configurations of 1.2 or 4 mirror ratio. The experiment was carried out at the GEKKO XII and LFEX laser facility. Spatial pattern of the REB was measured by coherent transition radiation and/or Cu Ka x ray emission from the rear surface of the foil targets. Strong collimation of the REB by the external magnetic field was observed with 50 μm thick plastic targets, while the REB scattered in 250 μm thick targets. The experimental results are compared with computer simulations to understand the physical mechanisms of the REB transport in the external magnetic field. This work is supported by NIFS (Japan), MEXT/JSPS KAKENHI (Japan), JSPS Fellowship (Japan), ANR (France) and COST (Europe).

  10. Solution of the Neutron transport equation in hexagonal geometry using strongly discontinuous nodal schemes

    International Nuclear Information System (INIS)

    Mugica R, C.A.; Valle G, E. del

    2005-01-01

    In 2002, E. del Valle and Ernest H. Mund developed a technique to solve numerically the Neutron transport equations in discrete ordinates and hexagonal geometry using two nodal schemes type finite element weakly discontinuous denominated WD 5,3 and WD 12,8 (of their initials in english Weakly Discontinuous). The technique consists on representing each hexagon in the union of three rhombuses each one of which it is transformed in a square in the one that the methods WD 5,3 and WD 12,8 were applied. In this work they are solved the mentioned equations of transport using the same discretization technique by hexagon but using two nodal schemes type finite element strongly discontinuous denominated SD 3 and SD 8 (of their initials in english Strongly Discontinuous). The application in each case as well as a reference problem for those that results are provided for the effective multiplication factor is described. It is carried out a comparison with the obtained results by del Valle and Mund for different discretization meshes so much angular as spatial. (Author)

  11. The Influence of Internal Model Variability in GEOS-5 on Interhemispheric CO2 Exchange

    Science.gov (United States)

    Allen, Melissa; Erickson, David; Kendall, Wesley; Fu, Joshua; Ott, Leslie; Pawson, Steven

    2012-01-01

    An ensemble of eight atmospheric CO2 simulations was completed employing the National Aeronautics and Space Administration (NASA) Goddard Earth Observation System, Version 5 (GEOS-5) for the years 2000-2001, each with initial meteorological conditions corresponding to different days in January 2000 to examine internal model variability. Globally, the model runs show similar concentrations of CO2 for the two years, but in regions of high CO2 concentrations due to fossil fuel emissions, large differences among different model simulations appear. The phasing and amplitude of the CO2 cycle at Northern Hemisphere locations in all of the ensemble members is similar to that of surface observations. In several southern hemisphere locations, however, some of the GEOS-5 model CO2 cycles are out of phase by as much as four months, and large variations occur between the ensemble members. This result indicates that there is large sensitivity to transport in these regions. The differences vary by latitude-the most extreme differences in the Tropics and the least at the South Pole. Examples of these differences among the ensemble members with regard to CO2 uptake and respiration of the terrestrial biosphere and CO2 emissions due to fossil fuel emissions are shown at Cape Grim, Tasmania. Integration-based flow analysis of the atmospheric circulation in the model runs shows widely varying paths of flow into the Tasmania region among the models including sources from North America, South America, South Africa, South Asia and Indonesia. These results suggest that interhemispheric transport can be strongly influenced by internal model variability.

  12. Subsonic aircraft soot. A tracer documenting barriers to inter-hemispheric mixing

    Energy Technology Data Exchange (ETDEWEB)

    Pueschel, R.F. [NASA Ames Research Center, Moffett Field, CA (United States)

    1997-12-31

    Meridional observations of soot aerosols and radioactive {sup 14}C, and models of the geographic distribution of nuclear bomb-released {sup 14}C and aircraft-emitted NO{sub x}, all show strong gradients between the hemispheres. Reason for it are decade-long inter-hemispheric mixing times which are much in excess of yearlong stratospheric residence times of tracers. Vertical mixing of soot aerosol is not corroborated by {sup 14}C observations. The reason could be radiometric forces that act on strongly absorbing soot. (author) 10 refs.

  13. Emotion and Interhemispheric Interactions in Binocular Rivalry

    Directory of Open Access Journals (Sweden)

    K L Ritchie

    2013-10-01

    Full Text Available Previous research has shown that fear-related stimuli presented in peripheral vision are preferentially processed over stimuli depicting other emotions. Furthermore, emotional content can influence dominance duration in binocular rivalry, with the period of dominance for an emotional image (e.g. a fearful face being significantly longer than a neutral image (e.g. a neutral face or a house. Experiment 1 of the current study combined these two ideas to investigate the role of emotion in binocular rivalry with face/house pairs viewed in the periphery. The results showed that faces were perceived as more dominant than houses, and fearful faces more so than neutral faces, even when viewed in the periphery. Experiment 2 extended this paradigm to present a rival pair in the periphery in each hemifield, with each eye either viewing the same stimulus in each location (traditional condition, or a different stimulus in each location (Diaz-Caneja condition. The results showed that the two pairs tended to rival in synchrony only in the traditional condition. Taken together, the results show that face dominance and emotion dominance in binocular rivalry persist in the periphery, and that interhemispheric interactions in binocular rivalry depend on an eye- as opposed to an object-based mechanism.

  14. Transport of Dirac fermions on the surface of strong topological insulator and graphene

    Energy Technology Data Exchange (ETDEWEB)

    Kundu, Arijit

    2012-06-14

    In this dissertation I study electronic transport through Dirac Fermions on the surface of strong topological insulator and graphene. I start by reviewing the physics of topological insulator and graphene and the low energy effective theory for the electronic states of the surface of a 3D strong topological insulator and graphene. Using this theory the electronic structure of the surface states of strong topological insulators of geometries with large surface to bulk ratio like nanowire and thin film are obtained. Then the energy spectrum and the spin-parity structure of the eigenstates for a finite size topological insulator quantum dot of the shape of a nanotube are considered. Numerical calculations show that even at the lowest energy scales, the ''spin-surface locking'' is broken, that is, the spin direction in a topologically protected surface mode is not locked to the surface. The calculations also show the existence of ''zero-momentum'' modes, and sub-gap states localized near the ''caps'' of the dot. Both the energy spectrum and the spin texture of the eigenstates are basically reproduced from an analytical surface Dirac fermion description. The results are compared to microscopic calculations using a tight-binding model for a strong topological insulator in a finite-length nanowire geometry, which shows qualitative similarity. Then, a theoretical study of electron-phonon scattering effects in thin films made of a strong topological insulator is presented. Phonons are modeled by isotropic elastic continuum theory with stress-free boundary conditions, and the interaction with the helical surface Dirac fermions is mediated by the deformation potential. The temperature-dependent electrical resistivity ρ(T) and the quasi-particle decay rate Γ(T) observable in photo-emission are computed numerically. The low and high-temperature power laws for both quantities are obtained analytically. Detailed

  15. Disorder effects on helical edge transport in graphene under a strong tilted magnetic field

    Science.gov (United States)

    Huang, Chunli; Cazalilla, Miguel A.

    2015-10-01

    In a recent experiment, Young et al. [Nature (London) 505, 528 (2014), 10.1038/nature12800] observed a metal to insulator transition as well as transport through helical edge states in monolayer graphene under a strong, tilted magnetic field. Under such conditions, the bulk is a magnetic insulator which can exhibit metallic conduction through helical edges. It was found that the two-terminal conductance of the helical channels deviates from the expected quantized value (=e2/h per edge, at zero temperature). Motivated by this observation, we study the effect of disorder on the conduction through the edge channels. We show that, unlike for helical edges of topological insulators in semiconducting quantum wells, a disorder Rashba spin-orbit coupling does not lead to backscattering, at least to leading order. Instead, we find that the lack of perfect antialignment of the electron spins in the helical channels to be the most likely cause for backscattering arising from scalar (i.e., spin-independent) impurities. The intrinsic spin-orbit coupling and other time-reversal symmetry-breaking and/or sublattice parity-breaking potentials also lead to (subleading) corrections to the channel conductance.

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

    International Nuclear Information System (INIS)

    Dorado, B.

    2010-09-01

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

  17. Colloid facilitated transport of strongly sorbing contaminants in natural porous media: mathematical modeling and laboratory column experiments.

    Science.gov (United States)

    Grolimund, Daniel; Borkovec, Michal

    2005-09-01

    Mobile colloidal particles may act as carriers of strongly sorbing contaminants in subsurface materials. Such colloid-facilitated transport can be induced by changes in salinity, similar to freshwater intrusion to a contaminated aquifer saturated with saltwater, or groundwater penetration into a contaminated site saturated with a dumpsite leachate. This process is studied for noncalcareous soil material with laboratory column experiments with sodium and calcium as major cations and with lead as a strongly sorbing model contaminant. The measured breakthrough curves of these elements were described with a mathematical transport model, which invokes release and deposition kinetics of the colloids, together with adsorption and desorption of the relevant ions to the solid matrix as well as to the suspended colloids. In particular, the specific coupling between colloid and solute transport is considered. The crux of a successful description of such colloidal transport processes is to capture the inhibition of the particle release by adsorbed divalent ions properly and explicitly to considerthe dependence of colloid release on the solution chemistry and the chemical conditions at the solid-liquid interface. Experiments and modeling address colloid-facilitated transport of lead out of a contaminated zone and through a noncontaminated zone, including effects of flow velocity and length of the noncontaminated zone. We finally show that colloid-facilitated transport can be suppressed by the injection of a suitably chosen solution of a calcium salt.

  18. Spin excitations in systems with hopping electron transport and strong position disorder in a large magnetic field

    Science.gov (United States)

    Shumilin, A. V.

    2016-10-01

    We discuss the spin excitations in systems with hopping electron conduction and strong position disorder. We focus on the problem in a strong magnetic field when the spin Hamiltonian can be reduced to the effective single-particle Hamiltonian and treated with conventional numerical technics. It is shown that in a 3D system with Heisenberg exchange interaction the spin excitations have a delocalized part of the spectrum even in the limit of strong disorder, thus leading to the possibility of the coherent spin transport. The spin transport provided by the delocalized excitations can be described by a diffusion coefficient. Non-homogenous magnetic fields lead to the Anderson localization of spin excitations while anisotropy of the exchange interaction results in the Lifshitz localization of excitations. We discuss the possible effect of the additional exchange-driven spin diffusion on the organic spin-valve devices.

  19. Interhemispheric interactions between the human primary somatosensory cortices.

    Directory of Open Access Journals (Sweden)

    Patrick Ragert

    Full Text Available In the somatosensory domain it is still unclear at which processing stage information reaches the opposite hemispheres. Due to dense transcallosal connections, the secondary somatosensory cortex (S2 has been proposed to be the key candidate for interhemispheric information transfer. However, recent animal studies showed that the primary somatosensory cortex (S1 might as well account for interhemispheric information transfer. Using paired median nerve somatosensory evoked potential recordings in humans we tested the hypothesis that interhemispheric inhibitory interactions in the somatosensory system occur already in an early cortical processing stage such as S1. Conditioning right S1 by electrical median nerve (MN stimulation of the left MN (CS resulted in a significant reduction of the N20 response in the target (left S1 relative to a test stimulus (TS to the right MN alone when the interstimulus interval between CS and TS was between 20 and 25 ms. No such changes were observed for later cortical components such as the N20/P25, N30, P40 and N60 amplitude. Additionally, the subcortically generated P14 response in left S1 was also not affected. These results document the existence of interhemispheric inhibitory interactions between S1 in human subjects in the critical time interval of 20-25 ms after median nerve stimulation.

  20. Agenesis of the corpus callosum with associated inter-hemispheric ...

    African Journals Online (AJOL)

    On examination they noted a normal general and neurological examination apart from some frontal lobe signs on mental status examination. He also had features of psychosis and labile mood. On CT brain scan he had agenesis of the corpus callosum (CC) with associated interhemispheric cyst and right frontal pachygyria.

  1. Altered Interhemispheric Functional Coordination in Chronic Tinnitus Patients

    Directory of Open Access Journals (Sweden)

    Yu-Chen Chen

    2015-01-01

    Full Text Available Purpose. Recent studies suggest that tinnitus may be due in part to aberrant callosal structure and interhemispheric interaction. To explore this hypothesis we use a novel method, voxel-mirrored homotopic connectivity (VMHC, to examine the resting-state interhemispheric functional connectivity and its relationships with clinical characteristics in chronic tinnitus patients. Materials and Methods. Twenty-eight chronic tinnitus patients with normal hearing thresholds and 30 age-, sex-, education-, and hearing threshold-matched healthy controls were included in this study and underwent the resting-state fMRI scanning. We computed the VMHC to analyze the interhemispheric functional coordination between homotopic points of the brain in both groups. Results. Compared to the controls, tinnitus patients showed significantly increased VMHC in the middle temporal gyrus, middle frontal gyrus, and superior occipital gyrus. In tinnitus patients, a positive correlation was found between tinnitus duration and VMHC of the uncus. Moreover, correlations between VMHC changes and tinnitus distress were observed in the transverse temporal gyrus, superior temporal pole, precentral gyrus, and calcarine cortex. Conclusions. These results show altered interhemispheric functional connectivity linked with specific tinnitus characteristics in chronic tinnitus patients, which may be implicated in the neuropathophysiology of tinnitus.

  2. Personality goes a long a way: an interhemispheric connectivity study

    Directory of Open Access Journals (Sweden)

    Sylco S. Hoppenbrouwers

    2010-11-01

    Full Text Available Throughout the development of psychology the delineation of personality has played a central role. Together with the NEO-PI-R, a questionnaire derived from the Five Factor Model of Personality, and recent advances in research technology it is now possible to investigate the relationship between personality features and neurophysiological brain processes. The NEO-FFI, the short version of the NEO-PI-R, reliably measures five main personality traits: Neuroticism, Extraversion, Openness to experience, Agreeableness and Conscientiousness. As behaviour and some psychiatric disorders have been related to interhemispheric connectivity, the present study used the combination of transcranial magnetic stimulation (TMS and electroencephalography (EEG to measure frontal interhemispheric connectivity and its association with personality as indexed by the NEO-FFI. Results demonstrated that prefrontal interhemispheric connectivity between the left and right dorsolateral prefrontal cortex (DLPFC correlates with Agreeableness in healthy subjects. This is the first study to relate personality features to interhemispheric connectivity through TMS-EEG and suggests that Agreeableness relates to the effectiveness of prefrontal communication between hemispheres.

  3. Diffuser Design for Marine Outfalls in Areas with Strong Currents, High waves and Sediment Transport

    DEFF Research Database (Denmark)

    Larsen, Torben

    1995-01-01

    The design of marine outfalls is often based on environmental criteria for a minimum initial dilution. Accordingly advanced diffuser arrangement are designed to fulfil these requirements. A large number of examples of malfunction and blocking in sea outfalls have occurred around the world...... as a result of this uncompromising consent to environmental demands. Two examples of unconventional design are given in this paper. Both cases involved risk of blockage of the diffuser section because of wave and current induced sediment transport The paper also discusses how acceptable far field dilution...

  4. Rapid interhemispheric switching during vocal production in a songbird.

    Directory of Open Access Journals (Sweden)

    Claude Z H Wang

    2008-10-01

    Full Text Available To generate complex bilateral motor patterns such as those underlying birdsong, neural activity must be highly coordinated across the two cerebral hemispheres. However, it remains largely elusive how this coordination is achieved given that interhemispheric communication between song-control areas in the avian cerebrum is restricted to projections received from bilaterally connecting areas in the mid- and hindbrain. By electrically stimulating cerebral premotor areas in zebra finches, we find that behavioral effectiveness of stimulation rapidly switches between hemispheres. In time intervals in which stimulation in one hemisphere tends to distort songs, stimulation in the other hemisphere is mostly ineffective, revealing an idiosyncratic form of motor dominance that bounces back and forth between hemispheres like a virtual ping-pong ball. The intervals of lateralized effectiveness are broadly distributed and are unrelated to simple spectral and temporal song features. Such interhemispheric switching could be an important dynamical aspect of neural coordination that may have evolved from simpler pattern generator circuits.

  5. Transport coefficients of InSb in a strong magnetic field

    International Nuclear Information System (INIS)

    Nakamura, Hiroaki; Ikeda, Kazuaki; Yamaguchi, Satarou

    1998-02-01

    Improvement of a superconducting magnet system makes induction of a strong magnetic field easier. This fact gives us a possibility of energy conversion by the Nernst effect. As the first step to study the Nernst element, we measured the conductivity, the Hall coefficient, the thermoelectric power and the Nernst coefficient of the InSb, which is one of candidates of the Nernst elements. From this experiment, it is concluded that the Nernst coefficient is smaller than the theoretical values. On the other hand, the conductivity, the Hall coefficient and the thermoelectric power has the values expected by the theory. (author)

  6. Interhemispheric functional connectivity in anorexia and bulimia nervosa.

    Science.gov (United States)

    Canna, Antonietta; Prinster, Anna; Monteleone, Alessio Maria; Cantone, Elena; Monteleone, Palmiero; Volpe, Umberto; Maj, Mario; Di Salle, Francesco; Esposito, Fabrizio

    2017-05-01

    The functional interplay between hemispheres is fundamental for behavioral, cognitive, and emotional control. Anorexia nervosa (AN) and bulimia nervosa (BN) have been largely studied with brain magnetic resonance imaging (MRI) in relation to the functional mechanisms of high-level processing, but not in terms of possible inter-hemispheric functional connectivity anomalies. Using resting-state functional MRI (fMRI), voxel-mirrored homotopic connectivity (VMHC) and regional inter-hemispheric spectral coherence (IHSC) were studied in 15 AN and 13 BN patients and 16 healthy controls (HC). Using T1-weighted and diffusion tensor imaging MRI scans, regional VMHC values were correlated with the left-right asymmetry of corresponding homotopic gray matter volumes and with the white matter callosal fractional anisotropy (FA). Compared to HC, AN patients exhibited reduced VMHC in cerebellum, insula, and precuneus, while BN patients showed reduced VMHC in dorso-lateral prefrontal and orbito-frontal cortices. The regional IHSC analysis highlighted that the inter-hemispheric functional connectivity was higher in the 'Slow-5' band in all regions except the insula. No group differences in left-right structural asymmetries and in VMHC vs. callosal FA correlations were significant in the comparisons between cohorts. These anomalies, not explained by structural changes, indicate that AN and BN, at least in their acute phase, are associated with a loss of inter-hemispheric connectivity in regions implicated in self-referential, cognitive control and reward processing. These findings may thus gather novel functional markers to explore aberrant features of these eating disorders. © 2016 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

  7. Norwegian concern over strongly increased Russian oil transport along the Norwegian coast

    International Nuclear Information System (INIS)

    2003-01-01

    The transport of oil from the northern parts of Russia along the coast of Norway will multiply in a few years. An analysis has shown that the risk of a shipwreck followed by pollution will then increase dramatically. The coastal population of North Norway has begun to demand that measures be taken, and they are backed by the military authorities, who say the preparedness must be considerably improved. Massive oil spills are not the only danger. Spills of ballast water from ships have introduced foreign species that disrupts the local eco systems. A number of bilateral agreements exist between Norway and Russia on prevention and notification of accidents, cooperative rescue work and environmental work. These agreements do not fully satisfy the need for notification and warning, however

  8. Net Fluorescein Flux Across Corneal Endothelium Strongly Suggests Fluid Transport is due to Electro-osmosis.

    Science.gov (United States)

    Sanchez, J M; Cacace, V; Kusnier, C F; Nelson, R; Rubashkin, A A; Iserovich, P; Fischbarg, J

    2016-08-01

    We have presented prior evidence suggesting that fluid transport results from electro-osmosis at the intercellular junctions of the corneal endothelium. Such phenomenon ought to drag other extracellular solutes. We have investigated this using fluorescein-Na2 as an extracellular marker. We measured unidirectional fluxes across layers of cultured human corneal endothelial (HCE) cells. SV-40-transformed HCE layers were grown to confluence on permeable membrane inserts. The medium was DMEM with high glucose and no phenol red. Fluorescein-labeled medium was placed either on the basolateral or the apical side of the inserts; the other side carried unlabeled medium. The inserts were held in a CO2 incubator for 1 h (at 37 °C), after which the entire volume of the unlabeled side was collected. After that, label was placed on the opposite side, and the corresponding paired sample was collected after another hour. Fluorescein counts were determined with a (Photon Technology) DeltaScan fluorometer (excitation 380 nm; emission 550 nm; 2 nm bwth). Samples were read for 60 s. The cells utilized are known to transport fluid from the basolateral to the apical side, just as they do in vivo in several species. We used 4 inserts for influx and efflux (total: 20 1-h periods). We found a net flux of fluorescein from the basolateral to the apical side. The flux ratio was 1.104 ± 0.056. That difference was statistically significant (p = 0.00006, t test, paired samples). The endothelium has a definite restriction at the junctions. Hence, an asymmetry in unidirectional fluxes cannot arise from osmosis, and can only point instead to paracellular solvent drag. We suggest, once more, that such drag is due to electro-osmotic coupling at the paracellular junctions.

  9. Decreased Resting-State Interhemispheric Functional Connectivity in Parkinson's Disease.

    Science.gov (United States)

    Luo, ChunYan; Guo, XiaoYan; Song, Wei; Zhao, Bi; Cao, Bei; Yang, Jing; Gong, QiYong; Shang, Hui-Fang

    2015-01-01

    Abnormalities in white matter integrity and specific functional network alterations have been increasingly reported in patients with Parkinson's disease (PD). However, little is known about the inter-hemispheric interaction in PD. Fifty-one drug naive patients with PD and 51 age- and gender-matched healthy subjects underwent resting-state functional magnetic resonance imaging (rs-fMRI) scans. We compared the inter-hemispheric resting-state functional connectivity between patients with PD and healthy controls, using the voxel-mirrored homotopic connectivity (VMHC) approach. Then, we correlated the results from VMHC and clinical features in PD patients. Relative to healthy subject, patients exhibited significantly lower VMHC in putamen and cortical regions associated with sensory processing and motor control (involving sensorimotor and supramarginal cortex), which have been verified to play a critical role in PD. In addition, there were inverse relationships between the UPDRS motor scores and VMHC in the sensorimotor, and between the illness duration and VMHC in the supramarginal gyrus in PD patients. Our results suggest that the functional coordination between homotopic brain regions is impaired in PD patients, extending previous notions about the disconnection of corticostriatal circuit by providing new evidence supporting a disturbance in inter-hemispheric connections in PD.

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

    International Nuclear Information System (INIS)

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

    2007-01-01

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

  11. Variation of the critical slab thickness with the degree of strongly anisotropic scattering in one-speed neutron transport theory

    International Nuclear Information System (INIS)

    Yildiz, C.

    1998-01-01

    The critical slab problem is studied in one-speed neutron transport theory using a linearly anisotropic kernel which combines forward and backward scattering. It is shown that, the recently observed non-monotonic variation of the thickness also exists in this strongly anisotropic case. In addition, the influence of the linear anisotropy on the critical thickness is analysed in detail. Numerical analysis for the critical thickness are performed using the spherical harmonics method and results are tabulated for selected illustrative cases as a function of different degrees of anisotropic scattering. Finally, some results are discussed and compared with those already obtained by other methods, the agreement is satisfactory. The spherical harmonic method gives generally accurate results in one dimensional geometry, and it is very suitable for the numerical solution of the neutron transport equation with linearly anisotropic scattering

  12. Establishing a Consistent Theory of Transport in Strongly Correlated Fermi Superfluids

    Science.gov (United States)

    Boyack, Rufus M.

    A diagrammatic method of obtaining exact gauge-invariant response functions in strongly correlated Fermi superfluids is implemented for several example condensed matter systems of current interest. These include: topological superfluids, high temperature superconductors, and superfluids with finite center-of-mass momentum pairing known as Fulde-Ferrell superfluids. Much of the literature on these systems has focused on single-particle properties or alternatively has invoked simple approximations to treat response functions. The goal is to show that, for this wide class of topical problems, one can compute exact response functions. This enables assessment of the validity of different physical scenarios and allows a very broad class of experiments to be addressed. The method developed is based on deriving the full electromagnetic vertex, which satisfies the Ward-Takahashi identity, and determining the collective modes in a manner compatible with the self-consistent gap equation. In the condensed phase of a superfluid and a superconductor, where gauge invariance is spontaneously broken, it is crucial to determine the collective modes from the gap equation in a manner which restores gauge invariance. Our diagrammatic framework provides a very general and powerful method for obtaining these collective modes in a variety of strongly correlated Fermi superfluids. We show that a full electromagnetic vertex satisfying the Ward-Takahashi identity ensures the f-sum rule is satisfied and thus charge is conserved. This diagrammatic method is implemented for both normal and superfluid phases. While there are no collective modes in the normal phase, the Ward-Takahashi identity plays a similarly important role. In particular, for the normal phase we study Rashba spin-orbit coupled Fermi gases with intrinsic pairing in the absence and presence of a magnetic field. Exact density and spin response functions are obtained, even in the absence of a spin conservation law, providing

  13. Interhemispheric inhibition during mental actions of different complexity.

    Directory of Open Access Journals (Sweden)

    Nicolas Gueugneau

    Full Text Available Several investigations suggest that actual and mental actions trigger similar neural substrates. Yet, neurophysiological evidences on the nature of interhemispheric interactions during mental movements are still meagre. Here, we asked whether the content of mental images, investigated by task complexity, is finely represented in the inhibitory interactions between the two primary motor cortices (M1s. Subjects' left M1 was stimulated by means of transcranial magnetic stimulation (TMS while they were performing actual or mental movements of increasing complexity with their right hand and exerting a maximum isometric force with their left thumb and index. Thus, we simultaneously assessed the corticospinal excitability in the right opponent pollicis muscle (OP and the ipsilateral silent period (iSP in the left OP during actual and mental movements. Corticospinal excitability in right OP increased during actual and mental movements, but task complexity-dependent changes were only observed during actual movements. Interhemispheric motor inhibition in the left OP was similarly modulated by task complexity in both mental and actual movements. Precisely, the duration and the area of the iSP increased with task complexity in both movement conditions. Our findings suggest that mental and actual movements share similar inhibitory neural circuits between the two homologous primary motor cortex areas.

  14. Changes in ocean vertical heat transport with global warming

    Science.gov (United States)

    Zika, Jan D.; Laliberté, Frédéric; Mudryk, Lawrence R.; Sijp, Willem P.; Nurser, A. J. G.

    2015-06-01

    Heat transport between the surface and deep ocean strongly influences transient climate change. Mechanisms setting this transport are investigated using coupled climate models and by projecting ocean circulation into the temperature-depth diagram. In this diagram, a "cold cell" cools the deep ocean through the downwelling of Antarctic waters and upwelling of warmer waters and is balanced by warming due to a "warm cell," coincident with the interhemispheric overturning and previously linked to wind and haline forcing. With anthropogenic warming, the cold cell collapses while the warm cell continues to warm the deep ocean. Simulations with increasingly strong warm cells, set by their mean Southern Hemisphere winds, exhibit increasing deep-ocean warming in response to the same anthropogenic forcing. It is argued that the partition between components of the circulation which cool and warm the deep ocean in the preindustrial climate is a key determinant of ocean vertical heat transport with global warming.

  15. Spinal subdural hematoma associated with traumatic intracranial interhemispheric subdural hematoma.

    Science.gov (United States)

    Wajima, Daisuke; Yokota, Hiroshi; Ida, Yuki; Nakase, Hiroyuki

    2012-01-01

    A 78-year-old female fell and hit the back of her head on the floor. Head computed tomography (CT) showed right acute interhemispheric subdural hematoma (ISDH). Her left hemiparesis worsened, so partial removal of ISDH was performed. The hemiparesis was improved, but leg monoparesis persisted. Lumbar magnetic resonance imaging showed spinal subdural hematoma (SSDH) at the S1-2 level. Nerve conduction velocity measurements at the knee joint to lower limb showed disappearance of the left peroneal nerve conduction wave, indicating that one of the causes of drop foot was common peroneal nerve palsy. With conservative therapy, her drop foot was gradually improved, then she recovered to walk with a stick and moved to a rehabilitation hospital. Lumbar MR imaging should be performed to rule out SSDH in a patient with posterior fossa subdural hematoma on initial head CT who develops leg palsy.

  16. Parkinson's disease: interhemispheric textural differences in MR images.

    Science.gov (United States)

    Sikiö, Minna; Holli, Kirsi K; Harrison, Lara C V; Ruottinen, Hanna; Rossi, Maija; Helminen, Mika T; Ryymin, Pertti; Paalavuo, Raija; Soimakallio, Seppo; Eskola, Hannu J; Elovaara, Irina; Dastidar, Prasun

    2011-10-01

    Early-stage diagnosis of Parkinson's disease (PD) is essential in making decisions related to treatment and prognosis. However, there is no specific diagnostic test for the diagnosis of PD. The aim of this study was to evaluate the role of texture analysis (TA) of magnetic resonance images in detecting subtle changes between the hemispheres in various brain structures in patients with early symptoms of parkinsonism. In addition, functional TA parameters for detecting textural changes are presented. Fifty-one patients with symptoms of PD and 20 healthy controls were imaged using a 3-T magnetic resonance device. Co-occurrence matrix-based TA was applied to detect changes in textures between the hemispheres in the following clinically interesting areas: dentate nucleus, basilar pons, substantia nigra, globus pallidus, thalamus, putamen, caudate nucleus, corona radiata, and centrum semiovale. The TA results were statistically evaluated using the Mann-Whitney U test. The results showed interhemispheric textural differences among the patients, especially in the area of basilar pons and midbrain. Concentrating on this clinically interesting area, the four most discriminant parameters were defined: co-occurrence matrix correlation, contrast, difference variance, and sum variance. With these parameters, differences were also detected in the dentate nucleus, globus pallidus, and corona radiata. On the basis of this study, interhemispheric differences in the magnetic resonance images of patients with PD can be identified by the means of co-occurrence matrix-based TA. The detected areas correlate with the current pathophysiologic and neuroanatomic knowledge of PD. Copyright © 2011 AUR. Published by Elsevier Inc. All rights reserved.

  17. GPS phase scintillation at high latitudes during geomagnetic storms of 7–17 March 2012 – Part 2: Interhemispheric comparison

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    P. Prikryl

    2015-06-01

    Full Text Available During the ascending phase of solar cycle 24, a series of interplanetary coronal mass ejections (ICMEs in the period 7–17 March 2012 caused geomagnetic storms that strongly affected high-latitude ionosphere in the Northern and Southern Hemisphere. GPS phase scintillation was observed at northern and southern high latitudes by arrays of GPS ionospheric scintillation and TEC monitors (GISTMs and geodetic-quality GPS receivers sampling at 1 Hz. Mapped as a function of magnetic latitude and magnetic local time (MLT, the scintillation was observed in the ionospheric cusp, the tongue of ionization fragmented into patches, sun-aligned arcs in the polar cap, and nightside auroral oval and subauroral latitudes. Complementing a companion paper (Prikryl et al., 2015a that focuses on the high-latitude ionospheric response to variable solar wind in the North American sector, interhemispheric comparison reveals commonalities as well as differences and asymmetries between the northern and southern high latitudes, as a consequence of the coupling between the solar wind and magnetosphere. The interhemispheric asymmetries are caused by the dawn–dusk component of the interplanetary magnetic field controlling the MLT of the cusp entry of the storm-enhanced density plasma into the polar cap and the orientation relative to the noon–midnight meridian of the tongue of ionization.

  18. Reduction of Interhemispheric Functional Connectivity in Sensorimotor and Visual Information Processing Pathways in Schizophrenia

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    Xu Lang

    2016-01-01

    Conclusions: Interhemispheric functional connectivity in the sensorimotor and visual processing pathways was reduced in patients with schizophrenia, but this reduction was unrelated to the disease state; thus, this reduction may serve as a trait marker of schizophrenia.

  19. Modulation of Cortical Interhemispheric Interactions by Motor Facilitation or Restraint

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    Ana Cristina Vidal

    2014-01-01

    Full Text Available Cortical interhemispheric interactions in motor control are still poorly understood and it is important to clarify how these depend on inhibitory/facilitatory limb movements and motor expertise, as reflected by limb dominance. Here we addressed this problem using functional magnetic resonance imaging (fMRI and a task involving dominant/nondominant limb mobilization in the presence/absence of contralateral limb restraint. In this way we could modulate excitation/deactivation of the contralateral hemisphere. Blocks of arm elevation were alternated with absent/present restraint of the contralateral limb in 17 participants. We found the expected activation of contralateral sensorimotor cortex and ipsilateral cerebellum during arm elevation. In addition, only the dominant arm elevation (hold period was accompanied by deactivation of ipsilateral sensorimotor cortex, irrespective of presence/absence of contralateral restraint, although the latter increased deactivation. In contrast, the nondominant limb yielded absent deactivation and reduced area of contralateral activation upon restriction. Our results provide evidence for a difference in cortical communication during motor control (action facilitation/inhibition, depending on the “expertise” of the hemisphere that controls action (dominant versus nondominant. These results have relevant implications for the development of facilitation/inhibition strategies in neurorehabilitation, namely, in stroke, given that fMRI deactivations have recently been shown to reflect decreases in neural responses.

  20. Long distance communication in the human brain: timing constraints for inter-hemispheric synchrony and the origin of brain lateralization

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    FRANCISCO ABOITIZ

    2003-01-01

    Full Text Available Analysis of corpus callosum fiber composition reveals that inter-hemispheric transmission time may put constraints on the development of inter-hemispheric synchronic ensembles, especially in species with large brains like humans. In order to overcome this limitation, a subset of large-diameter callosal fibers are specialized for fast inter-hemispheric transmission, particularly in large-brained species. Nevertheless, the constraints on fast inter-hemispheric communication in large-brained species can somehow contribute to the development of ipsilateral, intrahemispheric networks, which might promote the development of brain lateralization.

  1. Disturbed Interhemispheric Functional Connectivity Rather than Structural Connectivity in Irritable Bowel Syndrome

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    Rongfeng Qi

    2016-12-01

    Full Text Available Neuroimaging studies have demonstrated that irritable bowel syndrome (IBS—a relapsing functional bowel disorder—presents with disrupted brain connections. However, little is known about the alterations of interhemispheric functional connectivity and underlying structural connectivity in IBS. This study combined resting-state functional magnetic resonance imaging (MRI and diffusion tensor imaging (DTI to investigate changes in interhemispheric coordination in IBS patients. Resting-state functional and structural magnetic resonance images were acquired from 65 IBS patients and 67 healthy controls (matched for age, sex and educational level. Interhemispheric voxel-mirrored homotopic connectivity (VMHC was calculated and compared between groups. Homotopic regions showing abnormal VMHC in patients were targeted as regions of interest for analysis of DTI tractography. The fractional anisotropy, fiber number, and fiber length were compared between groups. Statistical analysis was also performed by including anxiety and depression as covariates to evaluate their effect. A Pearson correlation analysis between abnormal interhemispheric connectivity and clinical indices of IBS patients was performed. Compared to healthy controls, IBS patients had higher interhemispheric functional connectivity between bilateral thalami, cuneus, posterior cingulate cortices, lingual gyri and inferior occipital/cerebellum lobes, as well as lower interhemispheric functional connectivity between bilateral ventral anterior cingulate cortices (vACC and inferior parietal lobules (IPL. The inclusion of anxiety and depression as covariates abolished VMHC difference in vACC. Microstructural features of white matter tracts connecting functionally abnormal regions did not reveal any differences between the groups. VMHC values in vACC negatively correlated with the quality of life scores of patients. In conclusion, this study provides preliminary evidence of the disrupted

  2. Interhemispheric functional reorganization after cross nerve transfer: via cortical or subcortical connectivity?

    Science.gov (United States)

    Hua, Xu-Yun; Li, Zhan-Yu; Xu, Wen-Dong; Zheng, Mou-Xiong; Xu, Jian-Guang; Gu, Yu-Dong

    2012-08-30

    It has been demonstrated that there could be long range interhemispheric reorganization between bilateral hemispheres after peripheral cross nerve transfer. Our previous studies found a striking dynamic process of interhemispheric functional reorganization in adult rats with cross seventh cervical nerve transfer. But it remains a question whether the extensive interhemispheric functional reorganization after cross nerve transfer depends on connectivities at the cortical or subcortical level. In the present study, 18 rats with cross C7 transfer were concurrently treated with corpus callosotomy while the other 18 were not. Intracortical microstimulation was performed in the primary motor cortex (M1) at intervals of 5, 7, and 10 months postoperatively. The neural electrophysiology study showed that the representation of the injured forepaw appeared in the ipsilateral cortex at 5 months after the cross nerve transfer combined with corpus callosotomy, and it shared great overlapping zones with the representation of the health forepaw. And then, at 7-10 months, the cortical representation of the paralyzed forepaw was still located in the ipsilateral motor cortex, although significantly contracted. In contrast, rats with mere cross nerve transfer still presented interhemispheric reorganization. The results indicated that corpus callosotomy in the early stage after cross C7 transfer may had interrupted the interhemispheric functional reorganization. Combined the present study with our previous research findings, we explored the possible pathway and mechanisms of the interhemispheric functional reorganization. Thus we came to the conclusion that interhemispheric connectivity at the cortical level was essential in establishing the new contralateral control of the paralyzed limb at the initial stage after cross nerve transfer. Copyright © 2012 Elsevier B.V. All rights reserved.

  3. Alterations in Interhemispheric Functional and Anatomical Connectivity are Associated with Tobacco Smoking in Humans

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    Humsini eViswanath

    2015-03-01

    Full Text Available Abnormal interhemispheric functional connectivity correlates with several neurologic and psychiatric conditions, including depression, obsessive-compulsive disorder, schizophrenia, and stroke. Abnormal interhemispheric functional connectivity also correlates with abuse of cannabis and cocaine. In the current report, we evaluated whether tobacco abuse (i.e., cigarette smoking is associated with altered interhemispheric connectivity. To that end, we examined resting state functional connectivity using magnetic resonance imaging (MRI in short term tobacco deprived and smoking as usual tobacco smokers, and in non-smoker controls. Additionally, we compared diffusion tensor imaging (DTI in the same subjects to study differences in white matter. The data reveal a significant increase in interhemispheric functional connectivity in sated tobacco smokers when compared to controls. This difference was larger in frontal regions, and was positively correlated with the average number of cigarettes smoked per day. In addition, we found a negative correlation between the number of DTI streamlines in the genual corpus callosum and the number of cigarettes smoked per day. Taken together, our results implicate changes in interhemispheric functional and anatomical connectivity in current cigarette smokers.

  4. Auditory and visual interhemispheric communication in musicians and non-musicians.

    Science.gov (United States)

    Woelfle, Rebecca; Grahn, Jessica A

    2013-01-01

    The corpus callosum (CC) is a brain structure composed of axon fibres linking the right and left hemispheres. Musical training is associated with larger midsagittal cross-sectional area of the CC, suggesting that interhemispheric communication may be faster in musicians. Here we compared interhemispheric transmission times (ITTs) for musicians and non-musicians. ITT was measured by comparing simple reaction times to stimuli presented to the same hemisphere that controlled a button-press response (uncrossed reaction time), or to the contralateral hemisphere (crossed reaction time). Both visual and auditory stimuli were tested. We predicted that the crossed-uncrossed difference (CUD) for musicians would be smaller than for non-musicians as a result of faster interhemispheric transfer times. We did not expect a difference in CUDs between the visual and auditory modalities for either musicians or non-musicians, as previous work indicates that interhemispheric transfer may happen through the genu of the CC, which contains motor fibres rather than sensory fibres. There were no significant differences in CUDs between musicians and non-musicians. However, auditory CUDs were significantly smaller than visual CUDs. Although this auditory-visual difference was larger in musicians than non-musicians, the interaction between modality and musical training was not significant. Therefore, although musical training does not significantly affect ITT, the crossing of auditory information between hemispheres appears to be faster than visual information, perhaps because subcortical pathways play a greater role for auditory interhemispheric transfer.

  5. Auditory and visual interhemispheric communication in musicians and non-musicians.

    Directory of Open Access Journals (Sweden)

    Rebecca Woelfle

    Full Text Available The corpus callosum (CC is a brain structure composed of axon fibres linking the right and left hemispheres. Musical training is associated with larger midsagittal cross-sectional area of the CC, suggesting that interhemispheric communication may be faster in musicians. Here we compared interhemispheric transmission times (ITTs for musicians and non-musicians. ITT was measured by comparing simple reaction times to stimuli presented to the same hemisphere that controlled a button-press response (uncrossed reaction time, or to the contralateral hemisphere (crossed reaction time. Both visual and auditory stimuli were tested. We predicted that the crossed-uncrossed difference (CUD for musicians would be smaller than for non-musicians as a result of faster interhemispheric transfer times. We did not expect a difference in CUDs between the visual and auditory modalities for either musicians or non-musicians, as previous work indicates that interhemispheric transfer may happen through the genu of the CC, which contains motor fibres rather than sensory fibres. There were no significant differences in CUDs between musicians and non-musicians. However, auditory CUDs were significantly smaller than visual CUDs. Although this auditory-visual difference was larger in musicians than non-musicians, the interaction between modality and musical training was not significant. Therefore, although musical training does not significantly affect ITT, the crossing of auditory information between hemispheres appears to be faster than visual information, perhaps because subcortical pathways play a greater role for auditory interhemispheric transfer.

  6. Strong Coupling between Nanofluidic Transport and Interfacial Chemistry: How Defect Reactivity Controls Liquid-Solid Friction through Hydrogen Bonding.

    Science.gov (United States)

    Joly, Laurent; Tocci, Gabriele; Merabia, Samy; Michaelides, Angelos

    2016-04-07

    Defects are inevitably present in nanofluidic systems, yet the role they play in nanofluidic transport remains poorly understood. Here, we report ab initio molecular dynamics (AIMD) simulations of the friction of liquid water on defective graphene and boron nitride sheets. We show that water dissociates at certain defects and that these "reactive" defects lead to much larger friction than the "nonreactive" defects at which water molecules remain intact. Furthermore, we find that friction is extremely sensitive to the chemical structure of reactive defects and to the number of hydrogen bonds they can partake in with the liquid. Finally, we discuss how the insight obtained from AIMD can be used to quantify the influence of defects on friction in nanofluidic devices for water treatment and sustainable energy harvesting. Overall, we provide new insight into the role of interfacial chemistry on nanofluidic transport in real, defective systems.

  7. Which environmental factors most strongly influence a street's appeal for bicycle transport among adults? A conjoint study using manipulated photographs.

    Science.gov (United States)

    Mertens, Lieze; Van Dyck, Delfien; Ghekiere, Ariane; De Bourdeaudhuij, Ilse; Deforche, Benedicte; Van de Weghe, Nico; Van Cauwenberg, Jelle

    2016-09-01

    Micro-environmental factors (specific features within a streetscape), instead of macro-environmental factors (urban planning features), are more feasible to modify in existing neighborhoods and thus more practical to target for environmental interventions. Because it is often not possible to change the whole micro-environment at once, the current study aims to determine which micro-environmental factors should get the priority to target in physical environmental interventions increasing bicycle transport. Additionally, interaction effects among micro-environmental factors on the street's appeal for bicycle transport will be determined. In total, 1950 middle-aged adults completed a web-based questionnaire consisting of a set of 12 randomly assigned choice tasks with manipulated photographs. Seven micro-environmental factors (type of cycle path, speed limit, speed bump, vegetation, evenness of the cycle path surface, general upkeep and traffic density) were manipulated in each photograph. Conjoint analysis was used to analyze the data. Providing streets with a cycle path separated from motorized traffic seems to be the best strategy to increase the street's appeal for adults' bicycle transport. If this adjustment is not practically feasible, micro-environmental factors related to safety (i.e. speed limit, traffic density) may be more effective in promoting bicycle transport than micro-environmental factors related to comfort (i.e. evenness of the cycle path surface) or aesthetic (i.e. vegetation, general upkeep). On the other hand, when a more separated cycle path is already provided, micro-environmental factors related to comfort or aesthetic appeared to become more prominent. Findings obtained from this research could provide advice to physical environmental interventions about which environmental factors should get priority to modify in different environmental situations. The study was approved by the Ethics Committee of the Ghent University Hospital. B

  8. Practice makes a hemisphere perfect: The advantage of interhemispheric recruitment is eliminated with practice.

    Science.gov (United States)

    Weissman, Daniel; Compton, Rebecca

    2003-10-01

    As task performance improves with practice, oftentimes fewer brain areas are recruited to aid in processing. However, relatively little research has investigated how practice affects interactions between brain regions. Given prior work indicating that interhemispheric division of processing is most advantageous when task demands are high, we predicted that interactions between the cerebral hemispheres would be less advantageous after practice than before practice. This hypothesis was confirmed by reanalysis of data from two previously published studies. Practice reduced (1) the degree to which interhemispheric interaction facilitated performance for two letter-matching tasks (Experiment 1), and (2) the extent to which interhemispheric interaction reduced interference in a global-local perception task (Experiment 2). These findings illustrate the dynamic nature of neural recruitment in response to changing task demands.

  9. Novel Neuromodulation Techniques to Assess Interhemispheric Communication in Neural Injury and Neurodegenerative Diseases.

    Science.gov (United States)

    Shin, Samuel S; Pelled, Galit

    2017-01-01

    Interhemispheric interaction has a major role in various neurobehavioral functions. Its disruption is a major contributor to the pathological changes in the setting of brain injury such as traumatic brain injury, peripheral nerve injury, and stroke, as well as neurodegenerative diseases. Because interhemispheric interaction has a crucial role in functional consequence in these neuropathological states, a review of noninvasive and state-of-the-art molecular based neuromodulation methods that focus on or have the potential to elucidate interhemispheric interaction have been performed. This yielded approximately 170 relevant articles on human subjects or animal models. There has been a recent surge of reports on noninvasive methods such as transcranial magnetic stimulation and transcranial direct current stimulation. Since these are noninvasive techniques with little to no side effects, their widespread use in clinical studies can be easily justified. The overview of novel neuromodulation methods and how they can be applied to study the role of interhemispheric communication in neural injury and neurodegenerative disease is provided. Additionally, the potential of each method in therapeutic use as well as investigating the pathophysiology of interhemispheric interaction in neurodegenerative diseases and brain injury is discussed. New technologies such as transcranial magnetic stimulation or transcranial direct current stimulation could have a great impact in understanding interhemispheric pathophysiology associated with acquired injury and neurodegenerative diseases, as well as designing improved rehabilitation therapies. Also, advances in molecular based neuromodulation techniques such as optogenetics and other chemical, thermal, and magnetic based methods provide new capabilities to stimulate or inhibit a specific brain location and a specific neuronal population.

  10. Interhemispheric Transfer Time Asymmetry of Visual Information Depends on Eye Dominance: An Electrophysiological Study

    Directory of Open Access Journals (Sweden)

    Romain Chaumillon

    2018-02-01

    Full Text Available The interhemispheric transfer of information is a fundamental process in the human brain. When a visual stimulus appears eccentrically in one visual-hemifield, it will first activate the contralateral hemisphere but also the ipsilateral one with a slight delay due to the interhemispheric transfer. This interhemispheric transfer of visual information is believed to be faster from the right to the left hemisphere in right-handers. Such an asymmetry is considered as a relevant fact in the context of the lateralization of the human brain. We show here using current source density (CSD analyses of visually evoked potential (VEP that, in right-handers and, to a lesser extent in left-handers, this asymmetry is in fact dependent on the sighting eye dominance, the tendency we have to prefer one eye for monocular tasks. Indeed, in right-handers, a faster interhemispheric transfer of visual information from the right to left hemisphere was observed only in participants with a right dominant eye (DE. Right-handers with a left DE showed the opposite pattern, with a faster transfer from the left to the right hemisphere. In left-handers, albeit a smaller number of participants has been tested and hence confirmation is required, only those with a right DE showed an asymmetrical interhemispheric transfer with a faster transfer from the right to the left hemisphere. As a whole these results demonstrate that eye dominance is a fundamental determinant of asymmetries in interhemispheric transfer of visual information and suggest that it is an important factor of brain lateralization.

  11. Activations in gray and white matter are modulated by uni-manual responses during within and inter-hemispheric transfer: effects of response hand and right-handedness.

    Science.gov (United States)

    Diwadkar, Vaibhav A; Bellani, Marcella; Chowdury, Asadur; Savazzi, Silvia; Perlini, Cinzia; Marinelli, Veronica; Zoccatelli, Giada; Alessandrini, Franco; Ciceri, Elisa; Rambaldelli, Gianluca; Ruggieri, Mirella; Carlo Altamura, A; Marzi, Carlo A; Brambilla, Paolo

    2017-08-14

    Because the visual cortices are contra-laterally organized, inter-hemispheric transfer tasks have been used to behaviorally probe how information briefly presented to one hemisphere of the visual cortex is integrated with responses resulting from the ipsi- or contra-lateral motor cortex. By forcing rapid information exchange across diverse regions, these tasks robustly activate not only gray matter regions, but also white matter tracts. It is likely that the response hand itself (dominant or non-dominant) modulates gray and white matter activations during within and inter-hemispheric transfer. Yet the role of uni-manual responses and/or right hand dominance in modulating brain activations during such basic tasks is unclear. Here we investigated how uni-manual responses with either hand modulated activations during a basic visuo-motor task (the established Poffenberger paradigm) alternating between inter- and within-hemispheric transfer conditions. In a large sample of strongly right-handed adults (n = 49), we used a factorial combination of transfer condition [Inter vs. Within] and response hand [Dominant(Right) vs. Non-Dominant (Left)] to discover fMRI-based activations in gray matter, and in narrowly defined white matter tracts. These tracts were identified using a priori probabilistic white matter atlases. Uni-manual responses with the right hand strongly modulated activations in gray matter, and notably in white matter. Furthermore, when responding with the left hand, activations during inter-hemispheric transfer were strongly predicted by the degree of right-hand dominance, with increased right-handedness predicting decreased fMRI activation. Finally, increasing age within the middle-aged sample was associated with a decrease in activations. These results provide novel evidence of complex relationships between uni-manual responses in right-handed subjects, and activations during within- and inter-hemispheric transfer suggest that the organization of the

  12. Optical observations of Magnetosphere-Ionosphere coupling: Inter-hemispheric electron reflections within pulsating aurora

    Science.gov (United States)

    Samara, M.; Michell, R.; Khazanov, G. V.; Grubbs, G. A., II

    2017-12-01

    Magnetosphere-Ionosphere coupling is exhibited in reflected primary and secondary electrons which constitute the second step in the formation of the total precipitating electron distribution. While they have largely been missing from the current theoretical studies of particle precipitation, ground based observations point to the existence of a reflected electron population. We present evidence that pulsating aurora is caused by electrons bouncing back and forth between the two hemispheres. This means that these electrons are responsible for some of the total light in the aurora, a possibility that has largely been ignored in theoretical models. Pulsating auroral events imaged optically at high time resolution present direct observational evidence in agreement with the inter-hemispheric electron bouncing predicted by the SuperThermal Electron Trans-port (STET) model. Immediately following each of the `pulsation-on' times are equally spaced, and subsequently fainter pulsations, which can be explained by the primary precipitating electrons reflecting upwards from the ionosphere, traveling to the opposite hemisphere, and reflecting upwards again. The high time-resolution of these data, combined with the short duration of the `pulsation-on' time ( 1 s) and the relatively long spacing between pulsations ( 6 to 9 s) made it possible to observe the faint optical pulses caused by the reflected electrons coming from the opposite hemisphere. These results are significant and have broad implications because they highlight that the formation of the auroral electron distributions within regions of diffuse and pulsating aurora contain contributions from reflected primary and secondary electrons. These processes can ultimately lead to larger fluxes than expected when considering only the primary injection of magnetospheric electrons.

  13. Interhemispheric synchrony in the neonatal EEG revisited: Activation Synchrony Index as a promising classifier

    Directory of Open Access Journals (Sweden)

    Ninah eKoolen

    2014-12-01

    Full Text Available A key feature of normal neonatal EEG at term age is interhemispheric synchrony (IHS, which refers to the temporal co-incidence of bursting across hemispheres during trace alternant EEG activity. The assessment of IHS in both clinical and scientific work relies on visual, qualitative EEG assessment without clearly quantifiable definitions. A quantitative measure, activation synchrony index (ASI, was recently shown to perform well as compared to visual assessments. The present study set out to test whether IHS is stable enough for clinical use, and whether it could be an objective feature of EEG normality.We analyzed 31 neonatal EEG recordings that had been clinically classified as normal (n=14 or abnormal (n=17 using holistic, conventional visual criteria including amplitude, focal differences, qualitative synchrony, and focal abnormalities. We selected 20-minute epochs of discontinuous background pattern. ASI values were computed separately for different channel pair combinations and window lengths to define the optimal ASI intraindividual stability. Finally, ROC curves were computed to find trade-offs related to compromised data lengths, a common challenge in neonatal EEG studies.Using the average of four consecutive 2.5-minute epochs in the centro-occipital bipolar derivations gave ASI estimates that very accurately distinguished babies clinically classified as normal vs. abnormal. It was even possible to draw a cut-off limit (ASI~3.6 which correctly classified the EEGs in 97% of all cases. Finally, we showed that compromising the length of EEG segments from 20 minutes to 5 minutes leads to increased variability in ASI-based classification.Our findings support the prior literature that IHS is an important feature of normal neonatal brain function. We show that ASI may provide diagnostic value even at individual level, which strongly supports its use in prospective clinical studies on neonatal EEG as well as in the feature set of upcoming EEG

  14. Interhemispheric connectivity in amyotrophic lateral sclerosis: A near-infrared spectroscopy and diffusion tensor imaging study.

    Science.gov (United States)

    Kopitzki, Klaus; Oldag, Andreas; Sweeney-Reed, Catherine M; Machts, Judith; Veit, Maria; Kaufmann, Jörn; Hinrichs, Hermann; Heinze, Hans-Jochen; Kollewe, Katja; Petri, Susanne; Mohammadi, Bahram; Dengler, Reinhard; Kupsch, Andreas R; Vielhaber, Stefan

    2016-01-01

    Aim of the present study was to investigate potential impairment of non-motor areas in amyotrophic lateral sclerosis (ALS) using near-infrared spectroscopy (NIRS) and diffusion tensor imaging (DTI). In particular, we evaluated whether homotopic resting-state functional connectivity (rs-FC) of non-motor associated cortical areas correlates with clinical parameters and disease-specific degeneration of the corpus callosum (CC) in ALS. Interhemispheric homotopic rs-FC was assessed in 31 patients and 30 healthy controls (HCs) for 8 cortical sites, from prefrontal to occipital cortex, using NIRS. DTI was performed in a subgroup of 21 patients. All patients were evaluated for cognitive dysfunction in the executive, memory, and visuospatial domains. ALS patients displayed an altered spatial pattern of correlation between homotopic rs-FC values when compared to HCs ( p  = 0.000013). In patients without executive dysfunction a strong correlation existed between the rate of motor decline and homotopic rs-FC of the anterior temporal lobes (ATLs) (ρ = - 0.85, p  = 0.0004). Furthermore, antero-temporal homotopic rs-FC correlated with fractional anisotropy in the central corpus callosum (CC), corticospinal tracts (CSTs), and forceps minor as determined by DTI ( p  < 0.05). The present study further supports involvement of non-motor areas in ALS. Our results render homotopic rs-FC as assessed by NIRS a potential clinical marker for disease progression rate in ALS patients without executive dysfunction and a potential anatomical marker for ALS-specific degeneration of the CC and CSTs.

  15. Cortical interhemispheric responses to rhythmic stimulation are influenced by status epilepticus in developing rats

    Czech Academy of Sciences Publication Activity Database

    Tsenov, Grygoriy; Mareš, Pavel

    2005-01-01

    Roč. 46, č. S6 (2005), s. 209-210 ISSN 0013-9580. [International Epilepsy Congress /26./. 28.08.2005-01.09.2005, Paris] Institutional research plan: CEZ:AV0Z50110509 Keywords : status epilepticus * interhemispheric responses * developing rats Subject RIV: ED - Physiology

  16. Interhemispheric motor networks are abnormal in patients with Gilles de la Tourette syndrome

    DEFF Research Database (Denmark)

    Bäumer, Tobias; Thomalla, Götz; Kroeger, Johan

    2010-01-01

    Brain imaging has shown altered corpus callosum (CC) morphology in patients with Gilles de la Tourette syndrome (GTS). Yet it is unclear whether these morphological changes are associated with altered interhemispheric interactions. Here, we combined transcranial magnetic stimulation (TMS) with di...

  17. Reduced Interhemispheric Connectivity in Childhood Autism Detected by Electroencephalographic Photic Driving Coherence

    Science.gov (United States)

    Lazarev, Vladimir V.; Pontes, Adailton; Mitrofanov, Andrey A.; deAzevedo, Leonardo C.

    2015-01-01

    The EEG coherence among 14 scalp points during intermittent photic stimulation at 11 fixed frequencies of 3-24 Hz was studied in 14 boys with autism, aged 6-14 years, with relatively intact verbal and intellectual functions, and 19 normally developing boys. The number of interhemispheric coherent connections pertaining to the 20 highest…

  18. Increased Interhemispheric Interaction Is Associated with Decreased False Memories in a Verbal Converging Semantic Associates Paradigm

    Science.gov (United States)

    Christman, S.D.; Propper, R.E.; Dion, A.

    2004-01-01

    Recent evidence indicates that task and subject variables that are associated with increased interaction between the left and right cerebral hemispheres result in enhanced performance on tests of episodic memory. The current study looked at the effects of increased interhemispheric interaction on false memories using a verbal converging semantic…

  19. Interhemispheric Communication Involving Multiple Tasks: A Study of Children with Dyslexia

    Science.gov (United States)

    Sotozaki, Hiroko; Parlow, Shelley

    2006-01-01

    The study investigated whether inefficient interhemispheric communication is involved in developmental dyslexia using multiple tasks. A finger localization task, rhyming judgment task, primed lexical decision task, and a visual half-field presentation paradigm were used. Nineteen dyslexic children (mean age = 13.1 years) were compared with 26…

  20. Handedness and "Open-Earedness": Strong Right-Handers Are Less Likely to Prefer Less Popular Musical Genres

    Science.gov (United States)

    Christman, Stephen D.

    2013-01-01

    Research shows that strong right-handedness is associated with decreased cognitive flexibility and decreased tendencies to update beliefs, arising from decreased interhemispheric interaction. In the current study, strong right-handedness was associated with decreased overall liking of less popular musical genres (with the specific genres of…

  1. Astroglial-Mediated Remodeling of the Interhemispheric Midline Is Required for the Formation of the Corpus Callosum.

    LENUS (Irish Health Repository)

    Gobius, Ilan

    2016-01-01

    The corpus callosum is the major axon tract that connects and integrates neural activity between the two cerebral hemispheres. Although ∼1:4,000 children are born with developmental absence of the corpus callosum, the primary etiology of this condition remains unknown. Here, we demonstrate that midline crossing of callosal axons is dependent upon the prior remodeling and degradation of the intervening interhemispheric fissure. This remodeling event is initiated by astroglia on either side of the interhemispheric fissure, which intercalate with one another and degrade the intervening leptomeninges. Callosal axons then preferentially extend over these specialized astroglial cells to cross the midline. A key regulatory step in interhemispheric remodeling is the differentiation of these astroglia from radial glia, which is initiated by Fgf8 signaling to downstream Nfi transcription factors. Crucially, our findings from human neuroimaging studies reveal that developmental defects in interhemispheric remodeling are likely to be a primary etiology underlying human callosal agenesis.

  2. Quantification of LLAEP interhemispheric symmetry by the intraclass correlation coefficient as a measure of cortical reorganization after cochlear implantation

    NARCIS (Netherlands)

    Castaneda-Villa, Norma; Cornejo, Juan M.; James, Christopher J.; Maurits, Natasha M.

    2012-01-01

    Objective: Electrical stimulation by a cochlear implant (CI) induces maturation of the auditory system and reorganization of the auditory cortex in deaf children. Cortical reorganization produces an interhemispheric asymmetry in auditory evoked brain potentials associated with sound stimulation

  3. Search for Trends and Periodicities in Inter-hemispheric Sea Surface Temperature Difference

    Science.gov (United States)

    Rajesh, R.; Tiwari, R. K.

    2018-02-01

    Understanding the role of coupled solar and internal ocean dynamics on hemispheric climate variability is critical to climate modelling. We have analysed here 165 year long annual northern hemispheric (NH) and southern hemispheric (SH) sea surface temperature (SST) data employing spectral and statistical techniques to identify the imprints of solar and ocean-atmospheric processes, if any. We reconstructed the eigen modes of NH-SST and SH-SST to reveal non-linear oscillations superimposed on the monotonic trend. Our analysis reveals that the first eigen mode of NH-SST and SH-SST representing long-term trend of SST variability accounts for 15-23% variance. Interestingly, these components are matching with first eigen mode (99% variance) of the total solar irradiance (TSI) suggesting possible impact of solar activity on long-term SST variation. Furthermore, spectral analysis of SSA reconstructed signal revealed statistically significant periodicities of 63 ± 5, 22 ± 2, 10 ± 1, 7.6, 6.3, 5.2, 4.7, and 4.2 years in both NH-SST and SH-SST data. The major harmonics centred at 63 ± 5, 22 ± 2, and 10 ± 1 years are similar to solar periodicities and hence may represent solar forcing, while the components peaking at around 7.6, 6.3, 5.2, 4.7, and 4.2 years apparently falls in the frequency bands of El-Nino-Southern Oscillations linked to the oceanic internal processes. Our analyses also suggest evidence for the amplitude modulation of 9-11 and 21-22 year solar cycles, respectively, by 104 and 163 years in northern and southern hemispheric SST data. The absence of the above periodic oscillations in CO2 fails to suggest its role on observed inter-hemispheric SST difference. The cross-plot analysis also revealed strong influence of solar activity on linear trend of NH- and SH-SST in addition to small contribution from CO2. Our study concludes that (1) the long-term trends in northern and southern hemispheric SST variability show considerable synchronicity with cyclic

  4. Using a continuous index of laterality to determine how laterality is related to interhemispheric transfer and bimanual coordination in children.

    Science.gov (United States)

    Fagard, Jacqueline; Corroyer, Denis

    2003-07-01

    We sought to determine whether laterality is related to interhemispheric transfer and bimanual coordination during development. Children between 3 and 8 years of age were observed. In the first part of the experiment, we devised a continuous index to order the subjects according to their laterality. The laterality index included evaluation of hand and eye preference, and the right-left performance difference. In the second part of the experiment, we used this single index to determine whether laterality is related to interhemispheric transfer and bimanual coordination. Interhemispheric transfer was assessed by means of two tactile transfer tasks and one visuo-manual transfer task. We assessed bimanual coordination using the tapping task and the bimanual crank-rotation task. Results showed that right- and left-hand writers overlap on certain measures of laterality. They confirmed the improvement of interhemispheric transfer at around age 5 years, earlier progress in bimanual coordination with mirror than with parallel movements, and the existence of a relationship between visuo-manual interhemispheric transfer and bimanual coordination. The laterality index was not related to interhemispheric transfer, but it was related to the younger subjects' performance on the bimanual crank-rotation task: the less right handed, the better the bimanual coordination. In addition, on the same bimanual task, crossed hand-eye laterality was associated with better performance. Copyright 2003 Wiley Periodicals, Inc. Dev Psychobiol 43: 44-56, 2003.

  5. Resting state EEG power, intra-hemisphere and inter-hemisphere coherence in bipolar disorder

    Science.gov (United States)

    Handayani, Nita; Khotimah, S. N.; Haryanto, F.; Arif, I.; Taruno, Warsito P.

    2017-02-01

    This paper examines the differences of EEG power and coherence between bipolar disorder patients and healthy subjects in the resting state. Observations are focused on the prefrontal cortex area by calculating intra-hemisphere and inter-hemisphere coherence. EEG data acquisition are conducted by using wireless Emotiv Epoc on AF3, AF4, FC5, FC6, F7 and F8 channels. The power spectral analysis shows that in bipolar disoder there is an increase of power in the delta, theta and beta frequencies, and power decrease in the alpha frequency. The coherence test results show that both intra-hemisphere and inter-hemisphere coherence in bipolar disorder patients are lower than healthy subjects. This shows the lack of brain synchronization in bipolar disorder patients.

  6. Interhemispheric connectivity influences the degree of modulation of TMS-induced effects during auditory processing

    Directory of Open Access Journals (Sweden)

    Jamila eAndoh

    2011-07-01

    Full Text Available Repetitive TMS (rTMS has been shown to interfere with many components of language processing, including semantic, syntactic and phonologic. However, not much is known about its effects on primary auditory processing, especially its action on Heschl’s gyrus (HG. We aimed to investigate the behavioural and neural basis of rTMS during a melody processing task, while targeting the left HG, the right HG and the Vertex as a control site. Response Times (RT were normalized relative to the baseline-rTMS (Vertex and expressed as percentage change from baseline (%RT change. We also looked at sex differences in rTMS-induced response as well as in functional connectivity during melody processing using rTMS and functional Magnetic Resonance Imaging (fMRI.Functional MRI results showed an increase in the right HG compared with the left HG during the melody task, as well as sex differences in functional connectivity indicating a greater interhemispheric connectivity between left and right HG in females compared with males. TMS results showed that 10Hz-rTMS targeting the right HG induced differential effects according to sex, with a facilitation of performance in females and an impairment of performance in males. We also found a differential correlation between the %RT change after 10Hz-rTMS targeting the right HG and the interhemispheric functional connectivity between right and left HG, indicating that an increase in interhemispheric functional connectivity was associated with a facilitation of performance. This is the first study to report a differential rTMS-induced interference with melody processing depending on sex. In addition, we showed a relationship between the interference induced by rTMS on behavioral performance and the neural activity in the network connecting left and right HG, suggesting that the interhemispheric functional connectivity could determine the degree of modulation of behavioral performance.

  7. Intraventricular racemose type neurocysticercosis with anterior interhemispheric fissure cyst: A rare case report

    Directory of Open Access Journals (Sweden)

    Pankaj Gupta

    2015-01-01

    Full Text Available Racemose type of neurocysticercosis (NCC is a rare form of parasitic infestation of central nervous system. Most commonly it is found in fourth ventricle and cisterns. On reviewing the PubMed and Google databases, we found that this would be the first reported case of racemose type NCC in occipital horn of lateral ventricle with obstructive hydrocephalus, along with an incidental interhemispheric fissure arachnoid cyst.

  8. Refinements in the use of equivalent latitude for assimilating sporadic inhomogeneous stratospheric tracer observations, 1: Detecting transport of Pinatubo aerosol across a strong vortex edge

    Directory of Open Access Journals (Sweden)

    P. Good

    2004-01-01

    significantly affected. The analysis of the observations revealed a small amount of irreversible transport of aerosol across the vortex edge during late January 1992, coincident with a strongly disturbed vortex.

  9. Do horizontal saccadic eye movements increase interhemispheric coherence? Investigation of a hypothesized neural mechanism underlying EMDR

    Directory of Open Access Journals (Sweden)

    Zoe eSamara

    2011-03-01

    Full Text Available Series of horizontal saccadic eye movements (EMs are known to improve episodic memory retrieval in healthy adults and to facilitate the processing of traumatic memories in eye-movement desensitization and reprocessing (EMDR therapy. Several authors have proposed that EMs achieve these effects by increasing the functional connectivity of the two brain hemispheres, but direct evidence for this proposal is lacking. The aim of this study was to investigate whether memory enhancement following bilateral EMs is associated with increased interhemispheric coherence in the electroencephalogram (EEG. Fourteen healthy young adults were asked to freely recall lists of studied neutral and emotional words after a series of bilateral EMs and a control procedure. Baseline EEG activity was recorded before and after the EM and control procedures. Phase and amplitude coherence between bilaterally homologous brain areas were calculated for six frequency bands and electrode pairs across the entire scalp. Behavioral analyses showed that participants recalled more emotional (but not neutral words following the EM procedure than following the control procedure. However, the EEG analyses indicated no evidence that the EMs altered participants’ interhemispheric coherence or that improvements in recall were correlated with such changes in coherence. These findings cast doubt on the interhemispheric interaction hypothesis, and therefore may have important implications for future research on the neurobiological mechanism underlying EMDR.

  10. Agenesis of Anterior Falx Cerebri in Patient with Planned Interhemispheric Approach to Third Ventricle Mass.

    Science.gov (United States)

    Finch, Nathan W; Ding, Dale; Oldfield, Edward H; Druzgal, Jason

    2018-01-01

    Complete or partial agenesis of the falx cerebri may occur in pediatric patients with developmental anomalies. However, isolated agenesis of the falx in a developmentally normal adult is exceptionally rare. We describe the first reported case of a patient with a third ventricular mass associated with partial agenesis of the anterior falx cerebri, a circumstance that influenced surgical access to a third ventricular epidermoid cyst. A 60-year-old developmentally normal woman presented with progressively worsening aphasia and altered mental status. Brain magnetic resonance imaging showed obstructive hydrocephalus from a third ventricular mass. An anterior interhemispheric transcallosal approach was planned to remove the tumor. However, upon dural opening there was no evidence of a falx cerebri, an anomaly visible but not reported on the prior imaging studies. An interhemispheric fissure was present, but the medial frontal lobes were densely adherent, with multiple traversing veins within the superficial arachnoid of the fissure. Therefore, a left frontal transcortical approach was performed for microsurgical resection of the tumor. Histopathologic analysis identified the lesion to be an epidermoid cyst. Partial agenesis of the falx cerebri is exceedingly rare in a developmentally normal adult, particularly in the presence of an anatomically normal superior sagittal sinus. If present, however, it is important to note this association preoperatively because partial agenesis of the falx cerebri precludes an interhemispheric transcallosal approach to the lateral and third ventricles. Copyright © 2017 Elsevier Inc. All rights reserved.

  11. Splenium of Corpus Callosum: Patterns of Interhemispheric Interaction in Children and Adults

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    Maria G. Knyazeva

    2013-01-01

    Full Text Available The splenium of the corpus callosum connects the posterior cortices with fibers varying in size from thin late-myelinating axons in the anterior part, predominantly connecting parietal and temporal areas, to thick early-myelinating fibers in the posterior part, linking primary and secondary visual areas. In the adult human brain, the function of the splenium in a given area is defined by the specialization of the area and implemented via excitation and/or suppression of the contralateral homotopic and heterotopic areas at the same or different level of visual hierarchy. These mechanisms are facilitated by interhemispheric synchronization of oscillatory activity, also supported by the splenium. In postnatal ontogenesis, structural MRI reveals a protracted formation of the splenium during the first two decades of human life. In doing so, the slow myelination of the splenium correlates with the formation of interhemispheric excitatory influences in the extrastriate areas and the EEG synchronization, while the gradual increase of inhibitory effects in the striate cortex is linked to the local inhibitory circuitry. Reshaping interactions between interhemispherically distributed networks under various perceptual contexts allows sparsification of responses to superfluous information from the visual environment, leading to a reduction of metabolic and structural redundancy in a child's brain.

  12. Binaural beats increase interhemispheric alpha-band coherence between auditory cortices.

    Science.gov (United States)

    Solcà, Marco; Mottaz, Anaïs; Guggisberg, Adrian G

    2016-02-01

    Binaural beats (BBs) are an auditory illusion occurring when two tones of slightly different frequency are presented separately to each ear. BBs have been suggested to alter physiological and cognitive processes through synchronization of the brain hemispheres. To test this, we recorded electroencephalograms (EEG) at rest and while participants listened to BBs or a monaural control condition during which both tones were presented to both ears. We calculated for each condition the interhemispheric coherence, which expressed the synchrony between neural oscillations of both hemispheres. Compared to monaural beats and resting state, BBs enhanced interhemispheric coherence between the auditory cortices. Beat frequencies in the alpha (10 Hz) and theta (4 Hz) frequency range both increased interhemispheric coherence selectively at alpha frequencies. In a second experiment, we evaluated whether this coherence increase has a behavioral aftereffect on binaural listening. No effects were observed in a dichotic digit task performed immediately after BBs presentation. Our results suggest that BBs enhance alpha-band oscillation synchrony between the auditory cortices during auditory stimulation. This effect seems to reflect binaural integration rather than entrainment. Copyright © 2015 Elsevier B.V. All rights reserved.

  13. Decreased Resting-State Interhemispheric Functional Connectivity in Parkinson’s Disease

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    ChunYan Luo

    2015-01-01

    Full Text Available Background. Abnormalities in white matter integrity and specific functional network alterations have been increasingly reported in patients with Parkinson’s disease (PD. However, little is known about the inter-hemispheric interaction in PD. Methods. Fifty-one drug naive patients with PD and 51 age- and gender-matched healthy subjects underwent resting-state functional magnetic resonance imaging (rs-fMRI scans. We compared the inter-hemispheric resting-state functional connectivity between patients with PD and healthy controls, using the voxel-mirrored homotopic connectivity (VMHC approach. Then, we correlated the results from VMHC and clinical features in PD patients. Results. Relative to healthy subject, patients exhibited significantly lower VMHC in putamen and cortical regions associated with sensory processing and motor control (involving sensorimotor and supramarginal cortex, which have been verified to play a critical role in PD. In addition, there were inverse relationships between the UPDRS motor scores and VMHC in the sensorimotor, and between the illness duration and VMHC in the supramarginal gyrus in PD patients. Conclusions. Our results suggest that the functional coordination between homotopic brain regions is impaired in PD patients, extending previous notions about the disconnection of corticostriatal circuit by providing new evidence supporting a disturbance in inter-hemispheric connections in PD.

  14. Gödel, Escher, and degree of handedness: differences in interhemispheric interaction predict differences in understanding self-reference.

    Science.gov (United States)

    Niebauer, Christopher Lee; Garvey, Kilian

    2004-01-01

    Ramachandran (1995) theorised that the left hemisphere (LH) is specialised for making a single and consistent interpretation of the self and the world, whereas the right hemisphere (RH) is responsible for monitoring anomalies in reference to these interpretations. If the anomalous information reaches a threshold, it interacts with the LH to update these interpretations or beliefs. Because mixed handers may have greater degrees of interhemispheric interaction compared to strong handers, they may have a lower threshold for updating beliefs. Two previous studies found this to be the case (Niebauer, Aselage, & Schutte, 2002a; Niebauer, Christman, & Reid, 2002b). Because monitoring one's beliefs may involve metacognitive processes, i.e., cognitions about cognitions, this model was extended to help explain individual differences in understanding self-referential concepts. In the first two studies, mixed-handed participants displayed a greater understanding of self-reference using a conceptual description of Gödel's Incompleteness Theorem. In a third study, mixed-handed participants displayed greater appreciation for self-referential works of M. C. Escher. Implications for a neuropsychological model of metacognition are discussed.

  15. Differential language expertise related to white matter architecture in regions subserving sensory-motor coupling, articulation, and interhemispheric transfer.

    Science.gov (United States)

    Elmer, Stefan; Hänggi, Jürgen; Meyer, Martin; Jäncke, Lutz

    2011-12-01

    The technique of diffusion tensor imaging (DTI) has been used to investigate alterations in white matter architecture following long-term training and expertise. Professional simultaneous interpreters (SI) provide an ideal model for the investigation of training-induced plasticity due to the high demands placed on sound to motor mapping mechanisms, which are vital for executing fast interpretations. In line with our hypothesis, we found clusters with decreased fractional anisotropy (FA) in the SI group in brain regions previously shown to support sensory-motor coupling mechanisms and speech articulation (cluster extent family-wise error corrected, P architecture indicated by lower FA values in the SI group in the most anterior and posterior parts of the corpus callosum. Our results suggest that language expertise is accompanied by plastic adaptations in regions strongly involved in motor aspects of speech and in interhemispheric information transfer. These results have implications for our understanding of language expertise in relation to white matter adaptations. Copyright © 2010 Wiley Periodicals, Inc.

  16. Solution of the Neutron transport equation in hexagonal geometry using strongly discontinuous nodal schemes; Solucion de la Ecuacion de transporte de neutrones en geometria hexagonal usando esquemas nodales fuertemente discontinuos

    Energy Technology Data Exchange (ETDEWEB)

    Mugica R, C.A.; Valle G, E. del [IPN, ESFM, Departamento de Ingenieria Nuclear, 07738 Mexico D.F. (Mexico)]. e-mail: cmugica@ipn.mx

    2005-07-01

    In 2002, E. del Valle and Ernest H. Mund developed a technique to solve numerically the Neutron transport equations in discrete ordinates and hexagonal geometry using two nodal schemes type finite element weakly discontinuous denominated WD{sub 5,3} and WD{sub 12,8} (of their initials in english Weakly Discontinuous). The technique consists on representing each hexagon in the union of three rhombuses each one of which it is transformed in a square in the one that the methods WD{sub 5,3} and WD{sub 12,8} were applied. In this work they are solved the mentioned equations of transport using the same discretization technique by hexagon but using two nodal schemes type finite element strongly discontinuous denominated SD{sub 3} and SD{sub 8} (of their initials in english Strongly Discontinuous). The application in each case as well as a reference problem for those that results are provided for the effective multiplication factor is described. It is carried out a comparison with the obtained results by del Valle and Mund for different discretization meshes so much angular as spatial. (Author)

  17. Reduced fractional anisotropy of corpus callosum modulates inter-hemispheric resting state functional connectivity in migraine patients without aura.

    Science.gov (United States)

    Yuan, Kai; Qin, Wei; Liu, Peng; Zhao, Ling; Yu, Dahua; Zhao, Limei; Dong, Minghao; Liu, Jixin; Yang, Xuejuan; von Deneen, Karen M; Liang, Fanrong; Tian, Jie

    2012-01-01

    Diffusion tensor imaging (DTI) study revealed reduced fractional anisotropy (FA) values in the corpus callosum (CC) in migraine patients without aura. Abnormalities in white matter integrity, particularly in the CC, may affect inter-hemispheric resting state functional connectivity (RSFC). Unfortunately, relatively little is known about the alterations in functional interactions between the cerebral hemispheres during resting state in migraine patients without aura, and even less about how the inter-hemispheric RSFC are affected by the abnormalities of the CC. Twenty-one migraine patients without aura and 21 healthy controls participated in this study, age-, sex-, and education-matched. Tract-based spatial statistics (TBSS) was employed to investigate the white matter alterations of the CC. Meanwhile, voxel-mirrored homotopic connectivity (VMHC) was used to compare the inter-hemispheric RSFC differences between the patients and controls. TBSS analysis revealed reduced FA values in the genu and the splenium of CC in patient group. VMHC analysis showed decreased inter-hemispheric RSFC of anterior cingulate cortex (ACC) in migraine patients without aura relative to that of the controls. Furthermore, in migraine patients without aura, the reduced FA values of the genu of CC correlated with the decreased inter-hemispheric RSFC of the ACC. Our findings demonstrated that the migraine patients without aura showed reduced FA values of the genu of CC and decreased inter-hemispheric RSFC of the ACC. The correlation between the above structural and functional changes suggested that the reduced fractional anisotropy (FA) of CC modulates inter-hemispheric VMHC in migraine patients without aura. Our results demonstrated that the VMHC alterations of ACC can reflect the FA changes of the genu of CC in migraine patients without aura.

  18. Theoretical Analysis of Thermal Transport in Graphene Supported on Hexagonal Boron Nitride: The Importance of Strong Adhesion Due to π -Bond Polarization

    Science.gov (United States)

    Pak, Alexander J.; Hwang, Gyeong S.

    2016-09-01

    One important attribute of graphene that makes it attractive for high-performance electronics is its inherently large thermal conductivity (κ ) for the purposes of thermal management. Using a combined density-functional theory and classical molecular-dynamics approach, we predict that the κ of graphene supported on hexagonal boron nitride (h -BN) can be as large as 90% of the κ of suspended graphene, in contrast to the significant suppression of κ (more than 70% reduction) on amorphous silica. Interestingly, we find that this enhanced thermal transport is largely attributed to increased lifetimes of the in-plane acoustic phonon modes, which is a notable contrast from the dominant contribution of out-of-plane acoustic modes in suspended graphene. This behavior is possible due to the charge polarization throughout graphene that induces strong interlayer adhesion between graphene and h -BN. These findings highlight the potential benefit of layered dielectric substrates such as h -BN for graphene-based thermal management, in addition to their electronic advantages. Furthermore, our study brings attention to the importance of understanding the interlayer interactions of graphene with layered dielectric materials which may offer an alternative technological platform for substrates in electronics.

  19. Insulin Resistance-Associated Interhemispheric Functional Connectivity Alterations in T2DM: A Resting-State fMRI Study

    Directory of Open Access Journals (Sweden)

    Wenqing Xia

    2015-01-01

    Full Text Available We aim to investigate whether decreased interhemispheric functional connectivity exists in patients with type 2 diabetes mellitus (T2DM by using resting-state functional magnetic resonance imaging (rs-fMRI. In addition, we sought to determine whether interhemispheric functional connectivity deficits associated with cognition and insulin resistance (IR among T2DM patients. We compared the interhemispheric resting state functional connectivity of 32 T2DM patients and 30 healthy controls using rs-fMRI. Partial correlation coefficients were used to detect the relationship between rs-fMRI information and cognitive or clinical data. Compared with healthy controls, T2DM patients showed bidirectional alteration of functional connectivity in several brain regions. Functional connectivity values in the middle temporal gyrus (MTG and in the superior frontal gyrus were inversely correlated with Trail Making Test-B score of patients. Notably, insulin resistance (log homeostasis model assessment-IR negatively correlated with functional connectivity in the MTG of patients. In conclusion, T2DM patients exhibit abnormal interhemispheric functional connectivity in several default mode network regions, particularly in the MTG, and such alteration is associated with IR. Alterations in interhemispheric functional connectivity might contribute to cognitive dysfunction in T2DM patients.

  20. Estimates of interhemispheric transport of radioactive debris by the east African low-level jet stream

    International Nuclear Information System (INIS)

    Rangarajan, C.; Eapen, C.D.

    1981-01-01

    The movement of air masses across the equator by way of the east African low-level jet stream has been studied using fission products from the French nuclear tests of the South Pacific as tracers. The studies show that the transit time of air masses from Malagasy to India is 3--6 days and about 75% of the air mass on the west coast of India is from the southern hemisphere

  1. Pivotal role of hMT+ in long-range disambiguation of interhemispheric bistable surface motion.

    Science.gov (United States)

    Duarte, João Valente; Costa, Gabriel Nascimento; Martins, Ricardo; Castelo-Branco, Miguel

    2017-10-01

    It remains an open question whether long-range disambiguation of ambiguous surface motion can be achieved in early visual cortex or instead in higher level regions, which concerns object/surface segmentation/integration mechanisms. We used a bistable moving stimulus that can be perceived as a pattern comprehending both visual hemi-fields moving coherently downward or as two widely segregated nonoverlapping component objects (in each visual hemi-field) moving separately inward. This paradigm requires long-range integration across the vertical meridian leading to interhemispheric binding. Our fMRI study (n = 30) revealed a close relation between activity in hMT+ and perceptual switches involving interhemispheric segregation/integration of motion signals, crucially under nonlocal conditions where components do not overlap and belong to distinct hemispheres. Higher signal changes were found in hMT+ in response to spatially segregated component (incoherent) percepts than to pattern (coherent) percepts. This did not occur in early visual cortex, unlike apparent motion, which does not entail surface segmentation. We also identified a role for top-down mechanisms in state transitions. Deconvolution analysis of switch-related changes revealed prefrontal, insula, and cingulate areas, with the right superior parietal lobule (SPL) being particularly involved. We observed that directed influences could emerge either from left or right hMT+ during bistable motion integration/segregation. SPL also exhibited significant directed functional connectivity with hMT+, during perceptual state maintenance (Granger causality analysis). Our results suggest that long-range interhemispheric binding of ambiguous motion representations mainly reflect bottom-up processes from hMT+ during perceptual state maintenance. In contrast, state transitions maybe influenced by high-level regions such as the SPL. Hum Brain Mapp 38:4882-4897, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley

  2. Mid-latitude interhemispheric hydrologic seesaw over the past 550,000 years

    Science.gov (United States)

    Jo, Kyoung-Nam; Woo, Kyung Sik; Yi, Sangheon; Yang, Dong Yoon; Lim, Hyoun Soo; Wang, Yongjin; Cheng, Hai; Edwards, R. Lawrence

    2014-04-01

    An interhemispheric hydrologic seesaw--in which latitudinal migrations of the Intertropical Convergence Zone (ITCZ) produce simultaneous wetting (increased precipitation) in one hemisphere and drying in the other--has been discovered in some tropical and subtropical regions. For instance, Chinese and Brazilian subtropical speleothem (cave formations such as stalactites and stalagmites) records show opposite trends in time series of oxygen isotopes (a proxy for precipitation variability) at millennial to orbital timescales, suggesting that hydrologic cycles were antiphased in the northerly versus southerly subtropics. This tropical to subtropical hydrologic phenomenon is likely to be an initial and important climatic response to orbital forcing. The impacts of such an interhemispheric hydrologic seesaw on higher-latitude regions and the global climate system, however, are unknown. Here we show that the antiphasing seen in the tropical records is also present in both hemispheres of the mid-latitude western Pacific Ocean. Our results are based on a new 550,000-year record of the growth frequency of speleothems from the Korean peninsula, which we compare to Southern Hemisphere equivalents. The Korean data are discontinuous and derived from 24 separate speleothems, but still allow the identification of periods of peak speleothem growth and, thus, precipitation. The clear hemispheric antiphasing indicates that the sphere of influence of the interhemispheric hydrologic seesaw over the past 550,000 years extended at least to the mid-latitudes, such as northeast Asia, and that orbital-timescale ITCZ shifts can have serious effects on temperate climate systems. Furthermore, our result implies that insolation-driven ITCZ dynamics may provoke water vapour and vegetation feedbacks in northern mid-latitude regions and could have regulated global climate conditions throughout the late Quaternary ice age cycles.

  3. Inter-hemispheric integration of tactile-motor responses across body parts.

    Science.gov (United States)

    Tamè, Luigi; Longo, Matthew R

    2015-01-01

    In simple detection tasks, reaction times (RTs) are faster when stimuli are presented to the visual field or side of the body ipsilateral to the body part used to respond. This advantage, the crossed-uncrossed difference (CUD), is thought to reflect inter-hemispheric interactions needed for sensorimotor information to be integrated between the two cerebral hemispheres. However, it is unknown whether the tactile CUD is invariant when different body parts are stimulated. The most likely structure mediating such processing is thought to be the corpus callosum (CC). Neurophysiological studies have shown that there are denser callosal connections between regions that represent proximal parts of the body near the body midline and more sparse connections for regions representing distal extremities. Therefore, if the information transfer between the two hemispheres is affected by the density of callosal connections, stimuli presented on more distal regions of the body should produce a greater CUD compared to stimuli presented on more proximal regions. This is because interhemispheric transfer of information from regions with sparse callosal connections will be less efficient, and hence slower. Here, we investigated whether the CUD is modulated as a function of the different body parts stimulated by presenting tactile stimuli unpredictably on body parts at different distances from the body midline (i.e., Middle Finger, Forearm, or Forehead of each side of the body). Participants detected the stimulus and responded as fast as possible using either their left or right foot. Results showed that the magnitude of the CUD was larger on the finger (~2.6 ms) and forearm (~1.8 ms) than on the forehead (≃0.9 ms). This result suggests that the interhemispheric transfer of tactile stimuli varies as a function of the strength of callosal connections of the body parts.

  4. Occult falcine meningioma unmasked following nearly complete hemorrhagic transformation with resultant spontaneous acute interhemispheric subdural hematoma

    Directory of Open Access Journals (Sweden)

    Prasad Krishnan

    2015-01-01

    Full Text Available Sudden-onset monoplegia with features of vomiting and headache usually signals an intracranial cerebrovascular event. We describe a 62-year-old man in whom this presentation was the result of the rare occurrence of an almost complete hemorrhagic transformation of a falcine meningioma with resultant acute interhemispheric subdural hematoma, and discuss the risk factors and possible mechanisms that may lead to such an event. The need for careful examination of the available radiology and aggressive tumor removal is stressed.

  5. Unilateral frontal interhemispheric transfalcial approaches for the removal of olfactory groove meninjiomas.

    Science.gov (United States)

    Musluman, Ahmet Murat; Yilmaz, Adem; R, Tufan Canseve; Cavusoglu, Halit; Kahyaoglu, Okan; Aydin, Yunus

    2012-01-01

    A unilateral subfrontal interhemispheric transfalcial approach for the removal of olfactory groove meningiomas (OGM) was evaluated in terms of surgical technique, complications, clinical outcomes, and recurrence rate. Twenty-four females and eighteen males with a mean age of 59 years were operated on for OGM within a 12- year (1996-2008) period. The pre- and post-operative Mini-Mental Test (MMT) scores, visual impairment scores (VIS), pre-operative clinical symptoms (headache, epileptic seizure and anosmia), Karnofsky performance scores (KPS), tumor size and tumor extensions were evaluated. The effects of the pre-operative parameters on post-operative MMT, VIS and KPS were investigated. Tumor size and pre-operative MMT significantly affected pre-operative KPS. Mean tumor diameter was 5.6±0.8 cm. Total excision was achieved in 97.6% of all cases. No peri-operative mortality was seen. Ten patients (23.8%) experienced surgery-related complications. The mean follow-up period of cases was 52 months, and the rate of residual tumor re-growth was 2.3%. No parameter showed any effect on post-operative KPS, as no significant difference was seen between pre- and post-operative KPS. A significant positive difference was detected between pre- and post-operative MMT and VIS. A unilateral subfrontal interhemispheric transfalcial approach can be the preferred modality for treating OGM.

  6. Intra- and interhemispheric variations of diffusivity in subcortical white matter in normal human brain

    Energy Technology Data Exchange (ETDEWEB)

    Yoshiura, Takashi; Noguchi, Tomoyuki; Hiwatashi, Akio; Togao, Osamu; Yamashita, Koji; Nagao, Eiki; Kamano, Hironori; Honda, Hiroshi [Kyushu University, Department of Clinical Radiology, Graduate School of Medical Sciences, Fukuoka (Japan)

    2010-01-15

    Our purpose was to reveal potential regional variations in water molecular diffusivity within each cerebral hemisphere and across the right and left hemispheres. Diffusion-weighted images of 44 healthy right-handed adult male subjects were obtained using a diffusion tensor imaging sequence. Mean diffusivity (MD) values in subcortical white matter (WM) within 39 regions in each hemisphere were measured using an automated method. Intrahemispheric comparisons of MDs in subcortical WM were performed among six brain regions (frontal, parietal, occipital and temporal lobes and pre- and postcentral gyri). Interhemispheric comparisons of MDs were performed between the right and left counterparts of the 39 regions. In both hemispheres, diffusivity in the precentral gyrus was lower than those in other regions, while diffusivity in the parietal lobe was higher than others. MD asymmetry in which the left was lower than the right was found in the parietal lobe, middle occipital gyrus, and medial and orbital aspects of the frontal lobe. The converse asymmetry was revealed in the frontal operculum, supplementary motor cortex, temporal lobe, limbic cortices, precuneus and cuneus. Our results revealed significant intra- and interhemispheric regional variations in MD in subcortical WM, which may be related to different densities of axons and myelin sheaths. (orig.)

  7. Age Differences in Interhemispheric Interactions: Callosal Structure, Physiological Function, and Behavior

    Directory of Open Access Journals (Sweden)

    Brett W Fling

    2011-03-01

    Full Text Available There is a fundamental gap in understanding how brain structural and functional network connectivity are interrelated, how they change with age, and how such changes contribute to older adults’ sensorimotor deficits. Recent neuroimaging approaches including resting state functional connectivity MRI (fcMRI and diffusion tensor imaging (DTI have been used to assess brain functional (fcMRI and structural (DTI network connectivity, allowing for more integrative assessments of distributed neural systems than in the past. Declines in corpus callosum size and microstructure with advancing age have been well documented, but their contributions to age deficits in unimanual and bimanual function are not well defined. Our recent work implicates age-related declines in callosal size and integrity as a key contributor to unimanual and bimanual control deficits. Moreover, our data provide evidence for a fundamental shift in the balance of excitatory and inhibitory interhemispheric processes that occurs with age, resulting in age differences in the relationship between functional and structural network connectivity. Training studies suggest that the balance of interhemispheric interactions can be shifted with experience, making this a viable target for future interventions.

  8. Strongly capacitively coupled double quantum dots in GaAs-AlGaAs heterostructures. Preparation and electrical transport; Kapazitativ stark gekoppelte Doppelquantenpunkte in GaAs-AlGaAs-Heterostrukturen. Herstellung und elektrischer Transport

    Energy Technology Data Exchange (ETDEWEB)

    Huebel, A.

    2007-11-22

    In this work, a double quantum dot system is studied whose two dots are electrically insulated from one another and contacted independently with two leads. The geometry is optimized to maximize the capacitive interaction between the dots. The samples are characterized by electrical transport measurements in a dilution refrigerator. It is then studied at different tunnel couplings how the capacitive interaction influences the electrical transport in equilibrium. Under certain conditions correlated tunnel processes can be observed. A simple model is derived that serves to understand these processes. The double quantum dot system is defined in lateral arrangement by reactive ion etching of a two-dimensional electron system located only 50 nm below the surface of a GaAs-AlGaAs heterostructure. The samples are characterized in a dilution refrigerator at 25 mK near the common pinch-off point of all four tunnel barriers. A measurement of the differential equilibrium conductances of both quantum dots as a function of two gate voltages yields a honeycomb-like charge stability diagram. The most important sample characteristic is the ratio between the interaction capacitance and the total capacitance of a single quantum dot. For the optimized sample, this ratio turns out to be larger than one third near the common pinch-off point, with a single-dot charging energy of up to 800 {mu}eV. At more positive gate voltages, the capacitances between the quantum dots and their leads increase more and more, thereby diminishing the charging energy. It is shown for the optimized sample that all capacitance coefficients except the dot-lead capacitances are constant to within considerable accuracy over several Coulomb blockade oscillations. In order to measure correlated electrical transport in equilibrium, special parameter regions are examined in which the charges of both quantum dots cannot fluctuate independently of each other. An analytical formula is derived that describes the

  9. Transportation

    International Nuclear Information System (INIS)

    Anon.

    1998-01-01

    Here is the decree of the thirtieth of July 1998 relative to road transportation, to trade and brokerage of wastes. It requires to firms which carry out a road transportation as well as to traders and to brokers of wastes to declare their operations to the prefect. The declaration has to be renewed every five years. (O.M.)

  10. Decreased prefrontal lobe interhemispheric functional connectivity in adolescents with internet gaming disorder: a primary study using resting-state FMRI.

    Directory of Open Access Journals (Sweden)

    Yao Wang

    Full Text Available Recent neuroimaging studies have shown that people with Internet gaming disorder (IGD have structural and functional abnormalities in specific brain areas and connections. However, little is known about the alterations of the interhemispheric resting-state functional connectivity (rsFC in participants with IGD. In the present study, we used a newly developed voxel-mirrored homotopic connectivity (VMHC method to investigate the interhemispheric rsFC of the whole brain in participants with IGD.We compared interhemispheric rsFC between 17 participants with IGD and 24 healthy controls, group-matched on age, gender, and education status. All participants were provided written informed consent. Resting-state functional and structural magnetic resonance images were acquired for all participants. The rsFC between bilateral homotopic voxels was calculated. Regions showing abnormal VMHC in IGD participants were adopted as regions of interest for correlation analyses.Compared to healthy controls, IGD participants showed decreased VMHC between the left and right superior frontal gyrus (orbital part, inferior frontal gyrus (orbital part, middle frontal gyrus and superior frontal gyrus. Further analyses showed Chen Internet Addiction Scale (CIAS-related VMHC in superior frontal gyrus (orbital part and CIAS (r = -0.55, p = 0.02, uncorrected.Our findings implicate the important role of altered interhemispheric rsFC in the bilateral prefrontal lobe in the neuropathological mechanism of IGD, and provide further supportive evidence for the reclassification of IGD as a behavioral addiction.

  11. Asymmetry of planum temporale constrains interhemispheric language plasticity in children with focal epilepsy.

    Science.gov (United States)

    Pahs, Gerald; Rankin, Peter; Helen Cross, J; Croft, Louise; Northam, Gemma B; Liegeois, Frederique; Greenway, Sarah; Harrison, Sue; Vargha-Khadem, Faraneh; Baldeweg, Torsten

    2013-10-01

    Reorganization of eloquent cortex enables rescue of language functions in patients who sustain brain injury. Individuals with left-sided, early-onset focal epilepsy often show atypical (i.e. bilateral or right-sided) language dominance. Surprisingly, many patients fail to show such interhemispheric shift of language despite having major epileptogenic lesions in close proximity to eloquent cortex. Although a number of epilepsy-related factors may promote interhemispheric plasticity, it has remained unexplored if neuroanatomical asymmetries linked to human language dominance modify the likelihood of atypical lateralization. Here we examined the asymmetry of the planum temporale, one of the most striking asymmetries in the human brain, in relation to language lateralization in children with left-sided focal epilepsy. Language functional magnetic resonance imaging was performed in 51 children with focal epilepsy and left-sided lesions and 36 healthy control subjects. We examined the association of language laterality with a range of potential clinical predictors and the asymmetry of the length of the planum temporale. Using voxel-based methods, we sought to determine the effect of lesion location (in the affected left hemisphere) and grey matter density (in the unaffected right hemisphere) on language laterality. Atypical language lateralization was observed in 19 patients (38%) and in four controls (11%). Language laterality was increasingly right-sided in patients who showed atypical handedness, a left perisylvian ictal electroencephalographic focus, and a lesion in left anterior superior temporal or inferior frontal regions. Most striking was the relationship between rightward asymmetry of the planum temporale and atypical language (R = 0.70, P < 0.0001); patients with a longer planum temporale in the right (unaffected) hemisphere were more likely to have atypical language dominance. Voxel-based regression analysis confirmed that increased grey matter density in the

  12. Transportation

    National Research Council Canada - National Science Library

    Allshouse, Michael; Armstrong, Frederick Henry; Burns, Stephen; Courts, Michael; Denn, Douglas; Fortunato, Paul; Gettings, Daniel; Hansen, David; Hoffman, Douglas; Jones, Robert

    2007-01-01

    .... The ability of the global transportation industry to rapidly move passengers and products from one corner of the globe to another continues to amaze even those wise to the dynamics of such operations...

  13. Visual working memory gives up attentional control early in learning: ruling out interhemispheric cancellation.

    Science.gov (United States)

    Reinhart, Robert M G; Carlisle, Nancy B; Woodman, Geoffrey F

    2014-08-01

    Current research suggests that we can watch visual working memory surrender the control of attention early in the process of learning to search for a specific object. This inference is based on the observation that the contralateral delay activity (CDA) rapidly decreases in amplitude across trials when subjects search for the same target object. Here, we tested the alternative explanation that the role of visual working memory does not actually decline across learning, but instead lateralized representations accumulate in both hemispheres across trials and wash out the lateralized CDA. We show that the decline in CDA amplitude occurred even when the target objects were consistently lateralized to a single visual hemifield. Our findings demonstrate that reductions in the amplitude of the CDA during learning are not simply due to the dilution of the CDA from interhemispheric cancellation. Copyright © 2014 Society for Psychophysiological Research.

  14. Effects of stimulus pair orientation and hand switching on reaction time estimates of interhemispheric transfer.

    Science.gov (United States)

    Leblanc-Sirois, Yanick; Braun, Claude M J; Elie-Fortier, Jonathan

    2018-03-26

    Two behavioral estimates of interhemispheric transfer time, the crossed-uncrossed difference (CUD) and the unilateral field advantage (UFA), are thought to, respectively, index transfer of premotor and visual information across the corpus callosum in neurotypical participants. However, no attempt to manipulate visual and motor contingencies in a set of tasks while measuring the CUD and the UFA has yet been reported. In two go/no-go comparison experiments, stimulus pair orientations were manipulated. The hand of response changed after each correct response in the second, but not the first experiment. No correlation was found between the CUD and the UFA, supporting the hypothesis that these two measures index different types of information transfer across hemispheres. An effect of manipulation of stimulus pair orientation on UFAs was attributed to the homotopy of callosal fibers transferring visual information, while an effect of hand switching on CUDs was attributed mostly to spatial compatibility.

  15. Final Scientific Report for "The Interhemispheric Pattern in 20th Century and Future Abrupt Change in Regional Tropical Rainfall"

    Energy Technology Data Exchange (ETDEWEB)

    Chiang, John C. H. [University of California, Berkeley, CA (United States); Wehner, Michael F. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2012-10-29

    This is the final scientific report for grant DOE-FG02-08ER64588, "The Interhemispheric Pattern in 20th Century and Future Abrupt Change in Regional Tropical Rainfall."The project investigates the role of the interhemispheric pattern in surface temperature – i.e. the contrast between the northern and southern temperature changes – in driving rapid changes to tropical rainfall changes over the 20th century and future climates. Previous observational and modeling studies have shown that the tropical rainband – the Intertropical Convergence Zone (ITCZ) over marine regions, and the summer monsoonal rainfall over land – are sensitive to the interhemispheric thermal contrast; but that the link between the two has not been applied to interpreting long-term tropical rainfall changes over the 20th century and future.The specific goals of the project were to i) develop dynamical mechanisms to explain the link between the interhemispheric pattern to abrupt changes of West African and Asian monsoonal rainfall; ii) Undertake a formal detection and attribution study on the interhemispheric pattern in 20th century climate; and iii) assess the likelihood of changes to this pattern in the future. In line with these goals, our project has produced the following significant results: 1.We have developed a case that suggests that the well-known abrupt weakening of the West African monsoon in the late 1960s was part of a wider co-ordinated weakening of the West African and Asian monsoons, and driven from an abrupt cooling in the high latitude North Atlantic sea surface temperature at the same time. Our modeling work suggests that the high-latitude North Atlantic cooling is effective in driving monsoonal weakening, through driving a cooling of the Northern hemisphere that is amplified by positive radiative feedbacks. 2.We have shown that anthropogenic sulfate aerosols may have partially contributed to driving a progressively southward displacement of the Atlantic Intertropical

  16. APPRAISING THE STRONGLY ASSOCIATED IMPACTS TO CHOOSE THE MODE OF PUBLIC TRANSPORT: A CASE STUDY OF COLOMBO METROPOLITAN AREA IN SRI LANKA

    OpenAIRE

    Manjula Madhuwanthi; Ashuboda Marasinghe; Shusaku Nomura

    2016-01-01

    This study examines a model to evaluate the probability of choosing the mode of public transport with finding most significant aspects related to the characteristic of the journey, characteristic of the traveler and the personal behavior of the traveler. The study area was focused on eleven Divisional Secretariat Divisions of the Colombo Metropolitan Area in the Western Province of Sri Lanka. This area has the most economically advanced functions as the commercial capital of Sri Lanka. The cu...

  17. Gyrokinetic simulation of particle and heat transport in the presence of Wide orbits and strong profile variations in the Edge plasma

    Energy Technology Data Exchange (ETDEWEB)

    Heikkinen, J.A. [Euratom-Tekes Association, VTT, P.O. Box 1000, FI-02044 VTT (Finland); Henriksson, S.; Janhunen, S.; Kiviniemi, T.P. [Euratom-Tekes Association, Helsinki University of Technology, P.O. Box 2200, FI-02015 TKK (Finland); Ogando, F. [Euratom-Tekes Association, Helsinki University of Technology, P.O. Box 2200, FI-02015 TKK (Finland); Universidad Nacional de Educacion a Distancia, C/ Juan del Rosal, 12 28040 Madrid (Spain)

    2006-09-15

    A full f nonlinear 5D gyrokinetic electrostatic particle-in-cell code ELMFIRE using an implicit direct solution method for ion polarization drift and electron parallel velocity response to electric field and its validation are described. The developed code is applied for transport analysis in a tokamak plasma at steep pressure gradient. The role of turbulence and neoclassical equilibrium in determining the flux surface averaged radial electric field component are investigated, as well as the role of the latter in affecting the saturation level of the turbulence. (copyright 2006 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  18. Increased interhemispheric resting-state functional connectivity after sleep deprivation: a resting-state fMRI study.

    Science.gov (United States)

    Zhu, Yuanqiang; Feng, Zhiyan; Xu, Junling; Fu, Chang; Sun, Jinbo; Yang, Xuejuan; Shi, Dapeng; Qin, Wei

    2016-09-01

    Several functional imaging studies have investigated the regional effects of sleep deprivation (SD) on impaired brain function; however, potential changes in the functional interactions between the cerebral hemispheres after SD are not well understood. In this study, we used a recently validated approach, voxel-mirrored homotopic connectivity (VMHC), to directly examine the changes in interhemispheric homotopic resting-state functional connectivity (RSFC) after SD. Resting-state functional MRI (fMRI) was performed in 28 participants both after rest wakefulness (RW) and a total night of SD. An interhemispheric RSFC map was obtained by calculating the Pearson correlation (Fisher Z transformed) between each pair of homotopic voxel time series for each subject in each condition. The between-condition differences in interhemispheric RSFC were then examined at global and voxelwise levels separately. Significantly increased global VMHC was found after sleep deprivation; specifically, a significant increase in VMHC was found in specific brain regions, including the thalamus, paracentral lobule, supplementary motor area, postcentral gyrus and lingual gyrus. No regions showed significantly reduced VMHC after sleep deprivation. Further analysis indicates that these findings did not depend on the various sizes of smoothing kernels that were adopted in the preprocessing steps and that the differences in these regions were still significant with or without global signal regression. Our data suggest that the increased VMHC might reflect the compensatory involvement of bilateral brain areas, especially the bilateral thalamus, to prevent cognitive performance deterioration when sleep pressure is elevated after sleep deprivation. Our findings provide preliminary evidence of interhemispheric correlation changes after SD and contribute to a better understanding of the neural mechanisms of SD.

  19. Altered interhemispheric functional connectivity in patients with anisometropic and strabismic amblyopia: a resting-state fMRI study

    Energy Technology Data Exchange (ETDEWEB)

    Liang, Minglong; Xie, Bing; Yin, Xuntao; Wang, Jian [Third Military Medical University, Department of Radiology, Southwest Hospital, 30 Gaotanyan Street, Shapingba District, Chongqing (China); Yang, Hong; Wang, Hao [Third Military Medical University, Ophthalmology Research Center, Southwest Eye Hospital/Southwest Hospital, Chongqing (China); Yu, Longhua [Third Military Medical University, Department of Radiology, Southwest Hospital, 30 Gaotanyan Street, Shapingba District, Chongqing (China); 401st Hospital of PLA, Department of Radiology, Qingdao (China); He, Sheng [University of Minnesota Twin Cities, Department of Psychology, Minneapolis, MN (United States)

    2017-05-15

    Altered brain functional connectivity has been reported in patients with amblyopia by recent neuroimaging studies. However, relatively little is known about the alterations in interhemispheric functional connectivity in amblyopia. The present study aimed to investigate the functional connectivity patterns between homotopic regions across hemispheres in patients with anisometropic and strabismic amblyopia under resting state. Nineteen monocular anisometropic amblyopia (AA), 18 strabismic amblyopia (SA), and 20 normal-sight controls (NC) were enrolled in this study. After a comprehensive ophthalmologic examination, resting-state fMRI scanning was performed in all participants. The pattern of the interhemispheric functional connectivity was measured with the voxel-mirrored homotopic connectivity (VMHC) approach. VMHC values differences within and between three groups were compared, and correlations between VMHC values and each the clinical variable were also analyzed. Altered VMHC was observed in AA and SA patients in lingual gyrus and fusiform gyrus compared with NC subjects. The altered VMHC of lingual gyrus showed a pattern of AA > SA > NC, while the altered VMHC of fusiform gyrus showed a pattern of AA > NC > SA. Moreover, the VMHC values of lingual gyrus were positively correlated with the stereoacuity both in AA and SA patients, and the VMHC values of fusiform gyrus were positively correlated with the amount of anisometropia just in AA patients. These findings suggest that interhemispheric functional coordination between several homotopic visual-related brain regions is impaired both in AA and SA patients under resting state and revealed the similarities and differences in interhemispheric functional connectivity between the anisometropic and strabismic amblyopia. (orig.)

  20. Altered interhemispheric functional connectivity in patients with anisometropic and strabismic amblyopia: a resting-state fMRI study

    International Nuclear Information System (INIS)

    Liang, Minglong; Xie, Bing; Yin, Xuntao; Wang, Jian; Yang, Hong; Wang, Hao; Yu, Longhua; He, Sheng

    2017-01-01

    Altered brain functional connectivity has been reported in patients with amblyopia by recent neuroimaging studies. However, relatively little is known about the alterations in interhemispheric functional connectivity in amblyopia. The present study aimed to investigate the functional connectivity patterns between homotopic regions across hemispheres in patients with anisometropic and strabismic amblyopia under resting state. Nineteen monocular anisometropic amblyopia (AA), 18 strabismic amblyopia (SA), and 20 normal-sight controls (NC) were enrolled in this study. After a comprehensive ophthalmologic examination, resting-state fMRI scanning was performed in all participants. The pattern of the interhemispheric functional connectivity was measured with the voxel-mirrored homotopic connectivity (VMHC) approach. VMHC values differences within and between three groups were compared, and correlations between VMHC values and each the clinical variable were also analyzed. Altered VMHC was observed in AA and SA patients in lingual gyrus and fusiform gyrus compared with NC subjects. The altered VMHC of lingual gyrus showed a pattern of AA > SA > NC, while the altered VMHC of fusiform gyrus showed a pattern of AA > NC > SA. Moreover, the VMHC values of lingual gyrus were positively correlated with the stereoacuity both in AA and SA patients, and the VMHC values of fusiform gyrus were positively correlated with the amount of anisometropia just in AA patients. These findings suggest that interhemispheric functional coordination between several homotopic visual-related brain regions is impaired both in AA and SA patients under resting state and revealed the similarities and differences in interhemispheric functional connectivity between the anisometropic and strabismic amblyopia. (orig.)

  1. Altered interhemispheric functional connectivity in patients with anisometropic and strabismic amblyopia: a resting-state fMRI study.

    Science.gov (United States)

    Liang, Minglong; Xie, Bing; Yang, Hong; Yin, Xuntao; Wang, Hao; Yu, Longhua; He, Sheng; Wang, Jian

    2017-05-01

    Altered brain functional connectivity has been reported in patients with amblyopia by recent neuroimaging studies. However, relatively little is known about the alterations in interhemispheric functional connectivity in amblyopia. The present study aimed to investigate the functional connectivity patterns between homotopic regions across hemispheres in patients with anisometropic and strabismic amblyopia under resting state. Nineteen monocular anisometropic amblyopia (AA), 18 strabismic amblyopia (SA), and 20 normal-sight controls (NC) were enrolled in this study. After a comprehensive ophthalmologic examination, resting-state fMRI scanning was performed in all participants. The pattern of the interhemispheric functional connectivity was measured with the voxel-mirrored homotopic connectivity (VMHC) approach. VMHC values differences within and between three groups were compared, and correlations between VMHC values and each the clinical variable were also analyzed. Altered VMHC was observed in AA and SA patients in lingual gyrus and fusiform gyrus compared with NC subjects. The altered VMHC of lingual gyrus showed a pattern of AA > SA > NC, while the altered VMHC of fusiform gyrus showed a pattern of AA > NC > SA. Moreover, the VMHC values of lingual gyrus were positively correlated with the stereoacuity both in AA and SA patients, and the VMHC values of fusiform gyrus were positively correlated with the amount of anisometropia just in AA patients. These findings suggest that interhemispheric functional coordination between several homotopic visual-related brain regions is impaired both in AA and SA patients under resting state and revealed the similarities and differences in interhemispheric functional connectivity between the anisometropic and strabismic amblyopia.

  2. Blurring of the vessels of the interhemispheric fissure in multislice CT angiography: a sign of meningeal carcinomatosis

    International Nuclear Information System (INIS)

    Ertl-Wagner, Birgit B.; Hoffmann, Ralf-Thorsten; Herrmann, Karin; Reiser, Maximilian F.; Bruening, Roland; Dichgans, Martin

    2004-01-01

    Meningeal carcinomatosis remains a challenging diagnosis to make, with both cerebrospinal fluid (CSF) analysis and radiological methods having a limited sensitivity. We aimed at describing a possible diagnostic sign of multislice CT angiography (MS-CTA) in the diagnosis of meningeal carcinomatosis. Upon retrospective analysis of MSCT angiographies of the brain, a conspicuous sign of the vessels of the interhemispheric fissure was noted in five patients. Cranial MSCT angiographies were performed with a standardized protocol (120 kV, 200 mA s, collimation of 4 x 1 mm, table feed per rotation 4 mm). We injected 120 ml of nonionic contrast medium as a bolus, and data acquisition was started after a fixed delay of 35 s. In order to elucidate the finding, correlation with clinical follow-up and/or CSF findings was performed for all patients. In five patients there was a blurring, an increased number, and a pathologic configuration of the vessels of the interhemispheric fissure. All five patients with this sign had clinical signs and symptoms of meningeal carcinomatosis. Three patients had positive CSF cytology, one further patient had follow-up spinal MRI 6 weeks later demonstrating meningeal carcinomatosis. One patient declined lumbar puncture. MS-CTA has the capacity to demonstrate a pathologic configuration of the vessels of the interhemispheric fissure in patients with meningeal carcinomatosis. This sign may serve as an indicator of meningeal carcinomatosis and should raise the suspicion of this disease entity. (orig.)

  3. Interhemispheric Resting-State Functional Connectivity Predicts Severity of Idiopathic Normal Pressure Hydrocephalus

    Directory of Open Access Journals (Sweden)

    Yousuke Ogata

    2017-09-01

    Full Text Available Idiopathic normal pressure hydrocephalus (iNPH is characterized by a clinical triad (gait disturbance, dementia, and urinary incontinence, and by radiological findings of enlarged ventricles reflecting disturbance of central spinal fluid circulation. A diagnosis of iNPH is sometimes challenging, and the pathophysiological mechanisms underlying the clinical symptoms of iNPH remain largely unknown. Here, we used an emerging MRI technique, resting-state functional connectivity MRI (rsfcMRI, to develop a subsidiary diagnostic technique and to explore the underlying pathophysiological mechanisms of iNPH. rsfcMRI data were obtained from 11 patients with iNPH and 11 age-matched healthy volunteers, yielding rsfcMRI-derived functional connectivity (FC from both groups. A linear support vector machine classifier was trained to distinguish the patterns of FCs of the patients with iNPH from those of the healthy volunteers. After dimensional reduction, the support vector machine successfully classified the two groups with an accuracy of 80%. Moreover, we found that rsfcMRI-derived FC carried information to predict the severity of the triad in iNPH. FCs relevant to the classification of severity were mainly based on interhemispheric connectivity, suggesting that disruption of the corpus callosum fibers due to ventricular enlargement may explain the triad of iNPH. The present results support the usefulness of rsfcMRI as a tool to understand pathophysiology of iNPH, and also to help with its clinical diagnosis.

  4. Modeling Field Line Resonances in the Inner Plasmasphere with the Field Line Interhemispheric Plasma Model

    Science.gov (United States)

    McCarthy, N. M.; Jorgensen, A. M.; Stone, W. D.; Zesta, E.

    2010-12-01

    Equatorial plasma mass density in the Inner Magnetosphere of the Earth has been traditionally derived from measurements of Field Line Resonances from pairs of ground magnetometers closely spaced in latitude. The full plasma mass density along the flux tube can be determined using such measurements in an inversion of the Field Line Resonance Equation. Cummings et al [1969] developed the Field Line Resonance equation and numerically solved for the Field Line Resonances by assuming a power law distribution that varied with the geocentric distance from the equatorial crossing point of the field lines and a dipole model for the Earth's magnetic field. So far all numerical solutions of the Field Line Resonance Equation use some form of a power law distribution of the mass density along the field line, that depends on the magnetic field model, typically assumed to be a dipole, with only one recent work exploring deviations from a dipole magnetic field. Another fundamental assumption in the solution of the Field Line Resonance Equation is that of perfectly conducting, flat ionospheres as the two boundaries of the field line. While this assumption is considered valid for L values greater than 2, recent works have found it to be invalid for L values of 3 or less. In the present paper we solve the Field Line Resonance Equation for L values less than 3.5 using a three dimensional ionosphere, and without assuming a power law for the mass density distribution along the field line. Instead we use plasma mass density data from the Field Line Interhemispheric Plasma (FLIP) model to numerically solve the Field Line Resonance Equation for the eigenfrequencies. We also examine how the resonance frequencies vary as a function of the driving parameters. Finally we examine two events in which we compare the derived frequencies with measurements from the SAMBA magnetometer array.

  5. Superior interhemispheric approach for midline meningioma from the anterior cranial base.

    Science.gov (United States)

    Lévêque, S; Derrey, S; Martinaud, O; Gérardin, E; Langlois, O; Fréger, P; Hannequin, D; Castel, H; Proust, F

    2011-07-01

    For suprasellar meningioma, the fronto-basal exposure is considered the standard approach. The superior interhemispheric (IH) approach is less described in the literature. To assess the surgical complications, functional outcome (visual, olfaction), morbidity and mortality rates and late recurrence, after resection by superior IH approach of midline skull base meningioma. Between 1998 and 2008, 52 consecutive patients with midline meningioma on the anterior portion of the skull base (mean age: 63.8 ± 13.1; sex ratio F/M: 3.7) were operated on via the superior IH approach. After a mean follow-up of 56.9 ± 32.9 months, an independent neurosurgeon proposed a prospective examination of functional outcome to each patient, as well as a visual and olfactory function assessment. Fifty-two patients were divided into a group with olfactory groove meningioma (n=34) and another with tuberculum sellae meningioma (n=18). The outcome was characterized by postoperative complications in 13 patients (25%), mortality rate in two (3.8%) and long-term morbidity at in 17 (37%) of 50 surviving patients. Based on multivariate analysis, no prognosis factor was significant as regards the favorable outcome. The mean postoperative KPS score (86.6 ± 9.4) was significantly improved. However, dysexecutive syndrome was observed in four patients (8%), hyposmia-anosmia in 34 (68%) and visual acuity deteriorated in one (2%). The superior IH approach could be considered a safe anteriorly orientated midline approach for removal OGM and TSM meningioma. Copyright © 2011. Published by Elsevier Masson SAS.

  6. The Effectiveness of Repetitive Transcranial Magnetic Stimulation for Poststroke Apathy Is Associated with Improved Interhemispheric Functional Connectivity.

    Science.gov (United States)

    Mitaki, Shingo; Onoda, Keiichi; Abe, Satoshi; Oguro, Hiroaki; Yamaguchi, Shuhei

    2016-12-01

    Poststroke apathy is relatively common and has negative effects on the functional recovery of the patient; however, few reports have demonstrated the existence of effective treatments for poststroke apathy. Here, we describe a case of poststroke apathy that was successfully treated with repetitive transcranial magnetic stimulation (rTMS). Using resting-state functional magnetic resonance imaging, we detected improved interhemispheric functional connectivity that was correlated with the patient's recovery from poststroke apathy. Our case suggests that rTMS can improve the transfer of information through the corpus callosum, which is crucial for helping patients recover from poststroke apathy. Copyright © 2016 National Stroke Association. Published by Elsevier Inc. All rights reserved.

  7. Interhemispheric asymmetries in the occurrence of magnetically conjugate sub-auroral polarisation streams

    Directory of Open Access Journals (Sweden)

    M. L. Parkinson

    2005-06-01

    presence of AWFCs equatorward of the auroral oval. Systematic asymmetries in the interhemispheric signatures of the AWFCs probably arose because the magnetic flux tubes were distorted at L shells passing close to the substorm dipolarisation region. Transient asymmetries were attributed to the development of nearby field-aligned potential drops and currents.

  8. Interhemispheric Inhibition Induced by Transcranial Magnetic Stimulation Over Primary Sensory Cortex.

    Science.gov (United States)

    Iwata, Yasuyuki; Jono, Yasutomo; Mizusawa, Hiroki; Kinoshita, Atsushi; Hiraoka, Koichi

    2016-01-01

    The present study investigated whether the long-interval interhemispheric inhibition (LIHI) is induced by the transcranial magnetic stimulation over the primary sensory area (S1-TMS) without activation of the conditioning side of the primary motor area (M1) contributing to the contralateral motor evoked potential (MEP), whether the S1-TMS-induced LIHI is dependent on the status of the S1 modulated by the tactile input, and whether the pathways mediating the LIHI are different from those mediating the M1-TMS-induced LIHI. In order to give the TMS over the S1 without eliciting the MEP, the intensity of the S1-TMS was adjusted to be the sub-motor-threshold level and the trials with the MEP response elicited by the S1-TMS were discarded online. The LIHI was induced by the S1-TMS given 40 ms before the test TMS in the participants with the attenuation of the tactile perception of the digit stimulation (TPDS) induced by the S1-TMS, indicating that the LIHI is induced by the S1-TMS without activation of the conditioning side of the M1 contributing to the contralateral MEP in the participants in which the pathways mediating the TPDS is sensitive to the S1-TMS. The S1-TMS-induced LIHI was positively correlated with the attenuation of the TPDS induced by the S1-TMS, indicating that the S1-TMS-induced LIHI is dependent on the effect of the S1-TMS on the pathways mediating the TPDS at the S1. In another experiment, the effect of the digit stimulation given before the conditioning TMS on the S1- or M1-TMS-induced LIHI was examined. The digit stimulation produces tactile input to the S1 causing change in the status of the S1. The S1-TMS-induced LIHI was enhanced when the S1-TMS was given in the period in which the tactile afferent volley produced by the digit stimulation just arrived at the S1, while the LIHI induced by above-motor-threshold TMS over the contralateral M1 was not enhanced by the tactile input. Thus, the S1-TMS-induced LIHI is dependent on the status of the S1

  9. The anterior interhemispheric approach: a safe and effective approach to anterior skull base lesions.

    Science.gov (United States)

    Mielke, Dorothee; Mayfrank, Lothar; Psychogios, Marios Nikos; Rohde, Veit

    2014-04-01

    Many approaches to the anterior skull base have been reported. Frequently used are the pterional, the unilateral or bilateral frontobasal, the supraorbital and the frontolateral approach. Recently, endoscopic transnasal approaches have become more popular. The benefits of each approach has to be weighted against its complications and limitations. The aim of this study was to investigate if the anterior interhemispheric approach (AIA) could be a safe and effective alternative approach to tumorous and non-tumorous lesions of the anterior skull base. We screened the operative records of all patients with an anterior skull base lesion undergoing transcranial surgery. We have used the AIA in 61 patients. These were exclusively patients with either olfactory groove meningioma (OGM) (n = 43), ethmoidal dural arteriovenous fistula (dAVF) ( n = 6) or frontobasal fractures of the anterior midline with cerebrospinal fluid (CSF) leakage ( n = 12). Patient records were evaluated concerning accessibility of the lesion, realization of surgical aims (complete tumor removal, dAVF obliteration, closure of the dural tear), and approach related complications. The use of the AIA exclusively in OGMs, ethmoidal dAVFs and midline frontobasal fractures indicated that we considered lateralized frontobasal lesions not suitable to be treated successfully. If restricted to these three pathologies, the AIA is highly effective and safe. The surgical aim (complete tumor removal, complete dAVF occlusion, no rhinorrhea) was achieved in all patients. The complication rate was 11.5 % (wound infection (n = 2; 3.2 %), contusion of the genu of the corpus callosum, subdural hygroma, epileptic seizure, anosmia and asymptomatic bleed into the tumor cavity (n = 1 each). Only the contusion of the corpus callosum was directly related to the approach (1.6 %). Olfaction, if present before surgery, was preserved in all patients, except one (1.6 %). The AIA is an effective and a safe approach

  10. Individual differences in the dominance of interhemispheric connections predict cognitive ability beyond sex and brain size.

    Science.gov (United States)

    Martínez, Kenia; Janssen, Joost; Pineda-Pardo, José Ángel; Carmona, Susanna; Román, Francisco Javier; Alemán-Gómez, Yasser; Garcia-Garcia, David; Escorial, Sergio; Quiroga, María Ángeles; Santarnecchi, Emiliano; Navas-Sánchez, Francisco Javier; Desco, Manuel; Arango, Celso; Colom, Roberto

    2017-07-15

    Global structural brain connectivity has been reported to be sex-dependent with women having increased interhemispheric connectivity (InterHc) and men having greater intrahemispheric connectivity (IntraHc). However, (a) smaller brains show greater InterHc, (b) larger brains show greater IntraHc, and (c) women have, on average, smaller brains than men. Therefore, sex differences in brain size may modulate sex differences in global brain connectivity. At the behavioural level, sex-dependent differences in connectivity are thought to contribute to men-women differences in spatial and verbal abilities. But this has never been tested at the individual level. The current study assessed whether individual differences in global structural connectome measures (InterHc, IntraHc and the ratio of InterHc relative to IntraHc) predict spatial and verbal ability while accounting for the effect of sex and brain size. The sample included forty men and forty women, who did neither differ in age nor in verbal and spatial latent components defined by a broad battery of tests and tasks. High-resolution T 1 -weighted and diffusion-weighted images were obtained for computing brain size and reconstructing the structural connectome. Results showed that men had higher IntraHc than women, while women had an increased ratio InterHc/IntraHc. However, these sex differences were modulated by brain size. Increased InterHc relative to IntraHc predicted higher spatial and verbal ability irrespective of sex and brain size. The positive correlations between the ratio InterHc/IntraHc and the spatial and verbal abilities were confirmed in 1000 random samples generated by bootstrapping. Therefore, sex differences in global structural connectome connectivity were modulated by brain size and did not underlie sex differences in verbal and spatial abilities. Rather, the level of dominance of InterHc over IntraHc may be associated with individual differences in verbal and spatial abilities in both men and

  11. Children with ASD show links between aberrant sound processing, social symptoms, and atypical auditory interhemispheric and thalamocortical functional connectivity

    Directory of Open Access Journals (Sweden)

    Annika C. Linke

    2018-01-01

    Full Text Available Autism spectrum disorder (ASD is a complex and prevalent neurodevelopmental disorder characterized by social and communicative deficits, as well as repetitive behaviors and atypical sensitivity to sensory stimulation. Alterations in network connectivity are widely recognized, but their interplay with social and sensory symptoms remains largely unclear. Here, functional magnetic resonance imaging and diagnostic and behavioral assessments were used in a cohort of children and adolescents with ASD (n = 40 and matched typically developing (TD, n = 38 controls to examine the relation between auditory processing, interhemispheric and thalamocortical network connectivity, and social-behavioral symptom severity. We found that atypical processing of sounds was related to social, cognitive, and communicative impairments. Additionally, severity of sensory processing deficits and lower verbal IQ were related to reduced interhemispheric connectivity of auditory cortices in ASD. Increased connectivity between the thalamus and auditory cortex in ASD, however, was associated with reduced cognitive and behavioral symptomatology, suggesting that thalamocortical overconnectivity might reflect a compensatory mechanism in ASD. These findings provide novel evidence for links between auditory sensory deficits and impairments in social interaction and communication. Keywords: Auditory, Functional connectivity, Thalamus, Corpus callosum, fMRI, Autism spectrum disorder

  12. Resting-state interhemispheric motor connectivity and white matter integrity correlate with motor impairment in chronic stroke

    Directory of Open Access Journals (Sweden)

    Joyce L Chen

    2013-11-01

    Full Text Available Functional and structural reorganization in the brain occurs after stroke. The ability to predict motor outcomes may depend on patterns of brain functional and structural connectivity. We tested the hypothesis that alterations in motor transcallosal and corticospinal connections correlate with motor impairment in patients with chronic stroke. Eleven ischemic stroke patients underwent the Upper Extremity Fugl Meyer assessment, resting state functional magnetic resonance imaging, and diffusion tensor imaging. Twelve healthy control subjects underwent diffusion tensor imaging. We assessed the temporal coupling in neural activity between interhemispheric motor cortex, and white matter integrity by means of fractional anisotropy, in the transcallosal motor fibers and corticospinal tract. Partial correlation analyses were performed to determine whether these connectivity measures correlate with Upper Extremity Fugl Meyer scores. Patients compared to controls had reduced fractional anisotropy in common voxels of transcallosal motor and ipsilesional corticospinal fibers. Within the patient group those with higher interhemispheric motor cortex connectivity and higher fractional anisotropy in the transcallosal motor fibers were less impaired. The results show that markers of functional and structural motor cortex connectivity correlate with motor impairment in the chronic stage of stroke.

  13. Evolution of Interhemispheric Sea-Surface Temperature Contrast in the Tropical Atlantic During Termination I

    Science.gov (United States)

    Kim, J.

    2001-12-01

    Meteorological and oceanographic studies show that interannual and decadal variability in tropical Atlantic sea-surface temperature (SST) strongly influences the climates over northeast Brazil, sub-Saharan Africa, as well as the Central American and Caribbean regions. In this context, it is worthwhile to reconstruct spatial temperature patterns for the longer-term tropical Atlantic SST history. In this study, a high-resolution alkenone-derived SST record from the subtropical eastern South Atlantic (core GeoB 1023-5) is compared with one from the tropical western North Atlantic (core M35003-4). This comparison reveals synchronous SST variations between both near equatorial Atlantic regions during the Heinrich Event 1 (H1) (18-15.5 cal kyr B.P.), but dipole-like SST variations during the Younger Dryas (YD) (13-11.5 cal kyr B.P.). To assess the relationship of SST variations between both regions, we calculated SST differences between cores GeoB 1023-5 and M35003-4, and compared it with the coccolithophorid Florisphaera profunda abundance record from the equatorial eastern Atlantic (core RC24-08) as an indicator of variations in intensity of south-easterly trade winds [McIntyre and Molfino, 1996]. This comparison suggests that synchronous warming in both regions during the H1 can be attributed to a reduced northward heat transport from the warm equatorial Atlantic to the cold high-latitude North Atlantic linked to the slowdown of thermohaline circulation overturning during cold events under full glacial conditions. However, dipole-like SST variations during the YD is probably more associated with strengthened south-easterly trade winds, which led to a strong upwelling-related cooling in the eastern South Atlantic region and concurrently enhanced advection of warm subtropical South Atlantic waters to the tropical western Atlantic during that time. Accordingly, a coupled oceanic-atmospheric process created a warm pool in the tropical western Atlantic and thus a dipole

  14. TransCom model simulations of CH4 and related species: linking transport, surface flux and chemical loss with CH4 variability in the troposphere and lower stratosphere

    Directory of Open Access Journals (Sweden)

    P. I. Palmer

    2011-12-01

    Full Text Available A chemistry-transport model (CTM intercomparison experiment (TransCom-CH4 has been designed to investigate the roles of surface emissions, transport and chemical loss in simulating the global methane distribution. Model simulations were conducted using twelve models and four model variants and results were archived for the period of 1990–2007. All but one model transports were driven by reanalysis products from 3 different meteorological agencies. The transport and removal of CH4 in six different emission scenarios were simulated, with net global emissions of 513 ± 9 and 514 ± 14 Tg CH4 yr−1 for the 1990s and 2000s, respectively. Additionally, sulfur hexafluoride (SF6 was simulated to check the interhemispheric transport, radon (222Rn to check the subgrid scale transport, and methyl chloroform (CH3CCl3 to check the chemical removal by the tropospheric hydroxyl radical (OH. The results are compared to monthly or annual mean time series of CH4, SF6 and CH3CCl3 measurements from 8 selected background sites, and to satellite observations of CH4 in the upper troposphere and stratosphere. Most models adequately capture the vertical gradients in the stratosphere, the average long-term trends, seasonal cycles, interannual variations (IAVs and interhemispheric (IH gradients at the surface sites for SF6, CH3CCl3 and CH4. The vertical gradients of all tracers between the surface and the upper troposphere are consistent within the models, revealing vertical transport differences between models. An average IH exchange time of 1.39 ± 0.18 yr is derived from SF6 time series. Sensitivity simulations suggest that the estimated trends in exchange time, over the period of 1996–2007, are caused by a change of SF6 emissions towards the tropics. Using six sets of emission scenarios, we show that the decadal average CH4 growth rate likely reached equilibrium in the early 2000s due to the flattening of anthropogenic emission growth since the late 1990s. Up to

  15. Interhemispheric asymmetries in the occurrence of magnetically conjugate sub-auroral polarisation streams

    Directory of Open Access Journals (Sweden)

    M. L. Parkinson

    2005-06-01

    ="$-$">55$^{circ}$$Lambda $. LANL geosynchronous satellite observations of energetic ion and electron fluxes monitored the effects of substorms in the inner magnetosphere (L${sim}$6. The radar-observed AWFC activity was coincident with activity observed at geosynchronous orbit, as well as westward current surges in the ionosphere observed using ground-based magnetometers. The location of AWFCs with respect to the auroral oval was inferred from FUV auroral images recorded on board the IMAGE spacecraft. DMSP SSIES ion drift measurements confirmed the presence of AWFCs equatorward of the auroral oval. Systematic asymmetries in the interhemispheric signatures of the AWFCs probably arose because the magnetic flux tubes were distorted at L shells passing close to the substorm dipolarisation region. Transient asymmetries were attributed to the development of nearby field-aligned potential drops and currents.

  16. Transcranial alternating current stimulation at beta frequency: lack of immediate effects on excitation and interhemispheric inhibition of the human motor cortex

    Directory of Open Access Journals (Sweden)

    Viola Rjosk

    2016-11-01

    Full Text Available Transcranial alternating current stimulation (tACS is a form of noninvasive brain stimulation and is capable of influencing brain oscillations and cortical networks. In humans, the endogenous oscillation frequency in sensorimotor areas peaks at 20 Hz. This beta-band typically occurs during maintenance of tonic motor output and seems to play a role in interhemispheric coordination of movements. Previous studies showed that tACS applied in specific frequency bands over primary motor cortex (M1 or the visual cortex modulates cortical excitability within the stimulated hemisphere. However, the particular impact remains controversial because effects of tACS were shown to be frequency, duration and location specific. Furthermore, the potential of tACS to modulate cortical interhemispheric processing, like interhemispheric inhibition (IHI, remains elusive. Transcranial magnetic stimulation (TMS is a noninvasive and well-tolerated method of directly activating neurons in superficial areas of the human brain and thereby a useful tool for evaluating the functional state of motor pathways. The aim of the present study was to elucidate the immediate effect of 10 min tACS in the β-frequency band (20 Hz over left M1 on IHI between M1s in 19 young, healthy, right-handed participants. A series of TMS measurements (MEP size, RMT, IHI from left to right M1 and vice versa was performed before and immediately after tACS or sham using a double-blinded, cross-over design. We did not find any significant tACS-induced modulations of intracortical excitation (as assessed by MEP size and RMT and/or interhemispheric inhibition (IHI. These results indicate that 10 min of 20 Hz tACS over left M1 seems incapable of modulating immediate brain activity or inhibition. Further studies are needed to elucidate potential aftereffects of 20 Hz tACS as well as frequency-specific effects of tACS on intracortical excitation and interhemispheric inhibition.

  17. Prevalence of inter-hemispheric asymetry in children and adolescents with interdisciplinary diagnosis of non-verbal learning disorder.

    Science.gov (United States)

    Wajnsztejn, Alessandra Bernardes Caturani; Bianco, Bianca; Barbosa, Caio Parente

    2016-01-01

    To describe clinical and epidemiological features of children and adolescents with interdisciplinary diagnosis of non-verbal learning disorder and to investigate the prevalence of inter-hemispheric asymmetry in this population group. Cross-sectional study including children and adolescents referred for interdisciplinary assessment with learning difficulty complaints, who were given an interdisciplinary diagnosis of non-verbal learning disorder. The following variables were included in the analysis: sex-related prevalence, educational system, initial presumptive diagnoses and respective prevalence, overall non-verbal learning disorder prevalence, prevalence according to school year, age range at the time of assessment, major family complaints, presence of inter-hemispheric asymmetry, arithmetic deficits, visuoconstruction impairments and major signs and symptoms of non-verbal learning disorder. Out of 810 medical records analyzed, 14 were from individuals who met the diagnostic criteria for non-verbal learning disorder, including the presence of inter-hemispheric asymmetry. Of these 14 patients, 8 were male. The high prevalence of inter-hemispheric asymmetry suggests this parameter can be used to predict or support the diagnosis of non-verbal learning disorder. Descrever as características clínicas e epidemiológicas de crianças e adolescentes com transtorno de aprendizagem não verbal, e investigar a prevalência de assimetria inter-hemisférica neste grupo populacional. Estudo transversal que incluiu crianças e adolescentes encaminhados para uma avaliação interdisciplinar, com queixas de dificuldades de aprendizagem e que receberam diagnóstico interdisciplinar de transtorno de aprendizagem não verbal. As variáveis avaliadas foram prevalência por sexo, sistema de ensino, hipóteses diagnósticas iniciais e respectivas prevalências, prevalência de condições em relação à amostra total, prevalência geral do transtorno de aprendizagem não verbal

  18. Interhemispheric differences of fMRI responses to visual stimuli in patients with side-fixed migraine aura

    DEFF Research Database (Denmark)

    Hougaard, Anders; Amin, Faisal Mohammad; Hoffmann, Michael B

    2014-01-01

    Migraine sufferers with aura often report photosensitivity and visual discomfort outside of attacks and many consider bright or flickering light an attack-precipitating factor. The nature of this visual hypersensitivity and its relation to the underlying pathophysiology of the migraine aura...... is unknown. Using fMRI measurements during visual stimulation we examined the visual cortical responsiveness of patients with migraine with aura. We applied a within-patient design by assessing functional interhemispheric differences in patients consistently experiencing visual aura in the same visual...... hemifield. We recruited 20 patients with frequent side-fixed visual aura attacks (≥90% of auras occurring in the same visual hemifield) and 20 age and sex matched healthy controls and compared the fMRI blood oxygenation level dependent (BOLD) responses to visual stimulation between symptomatic...

  19. Interhemispheric ratio and annual cycle of carbonyl sulfide (OCS) total column from ground-based solar FTIR spectra

    Science.gov (United States)

    Griffith, David W. T.; Jones, Nicholas B.; Matthews, W. Andrew

    1998-04-01

    We have made extensive measurements of total column OCS by ground-based high-resolution solar Fourier transform infrared absorption spectroscopy from two southern hemisphere sites to complement earlier measurements in the northern hemisphere and to investigate the interhemispheric ratio, variability, and seasonal cycles of OCS in the atmosphere. The measurements were made at Lauder, New Zealand (45.0°S, 169.7°E, 370 m asl, 547 spectra March 1993 through April 1997), and Wollongong, Australia (34.45°S, 150.88°E, 30 m asl, 358 spectra May 1996 through April 1997). The annual mean column amounts are 9.15×1015 molecules cm-2 above Lauder and 9.84×1015 molecules cm-2 above Wollongong, corresponding to tropospheric mixing ratios of 480 and 490 parts per trillion by volume, respectively, with the assumed mixing ratio vertical profiles. The secular trend in total column OCS is less than 1% per year. Variability of all measurements about the means implies an atmospheric lifetime for OCS of at least 2.8 years. Comparison with earlier measurements in the northern hemisphere yields a north/south interhemispheric ratio in the range 1.1-1.2. There are peak-to-peak apparent annual cycles in total column OCS of 6% at Lauder and 18% at Wollongong with a late summer maximum. Seasonal tropopause height variation accounts for a 5-6% amplitude, and the remainder of the amplitude in Wollongong is assumed to be due to changes in the tropospheric mixing ratio.

  20. Intra- and Interhemispheric Propagation of Electrophysiological Synchronous Activity and Its Modulation by Serotonin in the Cingulate Cortex of Juvenile Mice.

    Directory of Open Access Journals (Sweden)

    Víctor Rovira

    Full Text Available Disinhibition of the cortex (e.g., by GABA -receptor blockade generates synchronous and oscillatory electrophysiological activity that propagates along the cortex. We have studied, in brain slices of the cingulate cortex of mice (postnatal age 14-20 days, the propagation along layer 2/3 as well as the interhemispheric propagation through the corpus callosum of synchronous discharges recorded extracellularly and evoked in the presence of 10 μM bicuculline by electrical stimulation of layer 1. The latency of the responses obtained at the same distance from the stimulus electrode was longer in anterior cingulate cortex (ACC: 39.53 ± 2.83 ms, n = 7 than in retrosplenial cortex slices (RSC: 21.99 ± 2.75 ms, n = 5; p<0.05, which is equivalent to a lower propagation velocity in the dorso-ventral direction in ACC than in RSC slices (43.0 mm/s vs 72.9 mm/s. We studied the modulation of this propagation by serotonin. Serotonin significantly increased the latency of the intracortical synchronous discharges (18.9% in the ipsilateral hemisphere and 40.2% in the contralateral hemisphere, and also increased the interhemispheric propagation time by 86.4%. These actions of serotonin were mimicked by the activation of either 5-HT1B or 5-HT2A receptors, but not by the activation of the 5-HT1A subtype. These findings provide further knowledge about the propagation of synchronic electrical activity in the cerebral cortex, including its modulation by serotonin, and suggest the presence of deep differences between the ACC and RSC in the structure of the local cortical microcircuits underlying the propagation of synchronous discharges.

  1. The compensatory dynamic of inter-hemispheric interactions in visuospatial attention revealed using rTMS and fMRI

    Directory of Open Access Journals (Sweden)

    Ela B Plow

    2014-04-01

    Full Text Available A balance of mutual tonic inhibition between bi-hemispheric posterior parietal cortices is believed to play an important role in bilateral visual attention. However, experimental support for this notion has been mainly drawn from clinical models of unilateral damage. We have previously shown that low-frequency repetitive TMS (rTMS over the intraparietal sulcus (IPS generates a contralateral attentional deficit in bilateral visual tracking. Here, we used functional Magnetic Resonance Imaging (fMRI to study whether rTMS temporarily disrupts the inter-hemispheric balance between bilateral IPS in visual attention. Following application of 1 Hz rTMS over the left IPS, subjects performed a bilateral visual tracking task while their brain activity was recorded using fMRI. Behaviorally, tracking accuracy was reduced immediately following rTMS. Areas ventro-lateral to left IPS, including inferior parietal lobule (IPL, lateral IPS (LIPS, and middle occipital gyrus (MoG, showed decreased activity following rTMS, while dorsomedial areas, such as Superior Parietal Lobule (SPL, Superior occipital gyrus (SoG, and lingual gyrus, as well as middle temporal areas (MT+, showed higher activity. The brain activity of the homologues of these regions in the un-stimulated, right hemisphere was reversed. Interestingly, the evolution of network-wide activation related to attentional behavior following rTMS showed that activation of most occipital synergists adaptively compensated for contralateral and ipsilateral decrement after rTMS, but that of parietal synergists, and SoG remained competing. This pattern of ipsilateral and contralateral activations empirically supports the hypothesized loss of inter-hemispheric balance that underlies clinical manifestation of visual attentional extinction.

  2. Evaluation of Inter-Hemispheric Characteristics of the Tropopause-Stratopause-Mesopause Over Sub-Tropical Regions

    Science.gov (United States)

    Sharma, Som; Kumar, Prashant; Vaishnav, Rajesh; Jethva, Chintan; Bencherif, Hassan

    2018-03-01

    The transition regions in thermal structure viz. Tropopause, stratopause and mesopause play a vital role in the vertical coupling of the Earth's atmosphere. For the first time, inter-hemispheric characteristics of the transition regions over two subtropical regions are studied using temperature observations from the SABER onboard TIMED satellite and the ERA Interim reanalysis during year 2002 to 2015. Results show that tropopause height is higher over Reunion Island (21.11°S, 55.53°E) in the Southern Hemisphere (SH) as compared to Mt. Abu region (24.59°N, 72.70°E) in the Northern Hemisphere (NH). Temporal variation of tropopause temperature reveals a decreasing ( 4 K) trend from year 2002 to 2008 and beyond this, an increasing ( 1.5 K) trend is found in tropopause temperature. These features are reinforcing for Mesopause as compared to tropopause temperature. The SH shows stronger variations in Mesopause temperature ( 7 K) compared to NH during year 2002 to 2008. The occurrence frequency of mesopause and stratopause height shows that the maximum occurrence frequency ( 60%) of mesopause at 100 km in NH, while frequency is found to be 55% in the SH. Results show that stratopause (mesopause) is cooler (warmer) in NH as compared SH. Moreover, Lomb Scargle Periodogram and wavelet transform techniques are used to investigate the periodicity of mesopause, stratopause and tropopause temperatures and heights. Investigations revealed prominent annual oscillations in the tropopause and stratopause temperatures in both hemispheres. These findings will be of immense use for the vertical and inter-hemispheric atmospheric coupling studies.

  3. Minimally invasive medial supraorbital, combined subfrontal-interhemispheric approach to the anterior communicating artery complex-a cadaveric study.

    Science.gov (United States)

    Spiessberger, Alexander; Baumann, F; Nevzati, E; Kothbauer, K F; Fandino, J; Muroi, C

    2017-06-01

    In selected cases, microsurgical clipping remains a valuable treatment alternative to endovascular occlusion of anterior communicating artery (AComA) aneurysms. Their clipping is challenging and carries a risk of postsurgical cognitive impairment. We evaluate the microsurgical anatomy of a new, minimally invasive combined interhemispheric-subfrontal approach to the AComA complex via a medial supraorbital craniotomy. In this descriptive anatomic study, four alcohol-embedded, silicon-injected human cadaver heads were used. In each of the two cadavers, the AComA complex was approached from either the right or left side. An operating microscope and standard microsurgical instruments were used. After a medial eyebrow incision, a medial supraorbital minicraniotomy was performed. The frontal sinus was opened and cranialized. Following the dural opening, a subfrontal arachnoid dissection was performed to identify the optico-carotid complex. By following the A1 segment, a low-lying AComA complex could be visualized. Shifting the corridor towards the midline enabled an interhemispheric dissection. This dissection resulted in a wide superior-inferior corridor. Higher-lying AComA complexes could also be visualized. The achieved exposure of the AComA complex would allow safe dissection and clipping of low- and high-lying AComA aneurysms, with minimal retraction and preservation of the surrounding anatomical structures, in particular the perforators. We demonstrate the anatomy of a novel approach for surgical clipping of AComA aneurysms. Our study suggests that this approach provides good exposure without concomitant structural and vascular injury and thus might reduce the risk of procedure-related morbidity.

  4. Brain stimulation therapy for central post-stroke pain from a perspective of interhemispheric neural network remodeling

    Directory of Open Access Journals (Sweden)

    Takashi eMorishita

    2016-04-01

    Full Text Available Central post-stroke pain (CPSP is a debilitating, severe disorder affecting patient quality of life. Since CPSP is refractory to medication, various treatment modalities have been tried with marginal results. Following the first report of epidural motor cortex stimulation (MCS for CPSP, many researchers have investigated the mechanisms of electrical stimulation of the motor cortex. CPSP is currently considered to be a maladapted network reorganization problem following stroke, and recent studies have revealed that the activities of the impaired hemisphere after stroke may be inhibited by the contralesional hemisphere. Even though this interhemispheric inhibition (IHI theory was originally proposed to explain the motor recovery process in stroke patients, we considered that IHI may also contribute to the CPSP mechanism. Based on the IHI theory and the fact that electrical stimulation of the motor cortex suppresses CPSP, we hypothesized that the inhibitory signals from the contralesional hemisphere may suppress the activities of the motor cortex in the ipsilesional hemisphere, and therefore pain suppression mechanisms may be malfunctioning in CPSP patients. In this context, transcranial direct current stimulation (tDCS was considered to be a reasonable procedure to address the interhemispheric imbalance, as the bilateral motor cortex can be simultaneously stimulated using an anode (excitatory and cathode (inhibitory. In this paper, we review the potential mechanisms and propose a new model of CPSP. We also report two cases where CPSP was addressed with transcranial direct current stimulation (tDCS, discuss the potential roles of tDCS in the treatment of CPSP, and make recommendations for future studies.

  5. Simulation of atmospheric krypton-85 transport to assess the detectability of clandestine nuclear reprocessing

    Energy Technology Data Exchange (ETDEWEB)

    Ross, Jens Ole

    2010-02-02

    The radioactive noble gas krypton-85 is released into the atmosphere during reprocessing of spent nuclear fuel or irradiated breeding targets. This is a necessary step for plutonium separation. Therefore the {sup 85}Kr signature of reprocessing could possibly be used for the detection of undeclared nuclear facilities producing nuclear weaponusable material. The {sup 85}Kr content of the atmosphere has grown over the last decades as the emissions from military and civilian nuclear industry could not be compensated by the decay with a half-life of 10.76 years. In this study, the global {sup 85}Kr background distribution due to emissions of known reprocessing facilities for the period from 1971 until 2006 was simulated using the atmospheric general circulation model ECHAM5 applying the newest available annual emission data. The convective tracer transport scheme and the operator splitting for the physical calculations in the model were modified in order to guarantee physically correct results for tracer point sources, in particular non negative concentrations. An on-line routine controlling the {sup 85}Kr -budget in the model enforced exact mass conservation. The results of the simulation were evaluated by extensive comparison with measurements performed by the German Federal Office for Radiation Protection with very good agreement at most observation sites except those in the direct vicinity of {sup 85}Kr sources. Of particular interest for the {sup 85}Kr detection potential was the variability of {sup 85}Kr background concentrations which was evaluated for the first time in a global model. In addition, the interhemispheric transport as simulated by ECHAM5 was analyzed using a two-box model providing a mean exchange time of τ {sub ex} = 10.5 months. The analysis of τ{sub ex} over simulated 35 years indicates that in years with strong South Asian or African Monsoon the interhemispheric transport is faster during the monsoon season. A correlation analysis of

  6. A flexible endoscope-assisted interhemispheric transcallosal approach through the contralateral ventricle for the removal of a third ventricle craniopharyngioma: A technical report.

    Science.gov (United States)

    Yano, Shigetoshi; Hide, Takuichiro; Shinojima, Naoki; Ueda, Yutaka; Kuratsu, Jun-Ichi

    2015-01-01

    Intraventricular craniopharyngiomas are difficult to remove. We combined an interhemispheric transcallosal approach with a flexible endoscope (videoscope) for successful tumor removal. A 52-year-old male complained of general fatigue and memory disturbance. Magnetic resonance imaging revealed a well-enhanced third ventricle mass with dilatation of lateral ventricles. During removal with the interhemispheric transcallosal approach, a videoscope that was inserted into the left lateral ventricle revealed the interface of the tumor and the ventricular wall. The tumor was pushed to the right using forceps and removed totally through the right foramen of Monro without any fornix injury. This procedure is a safe option for removing third ventricular tumors especially in the case with hydrocephalus.

  7. Testing strong interaction theories

    International Nuclear Information System (INIS)

    Ellis, J.

    1979-01-01

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

  8. Accelerating carbon uptake in the Northern Hemisphere - Evidence from the interhemispheric difference of atmospheric CO{sub 2} concentrations

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yuxuan [Ministry of Education Key Lab. for Earth System Modeling, Center for Earth System Science, Tsinghua Univ., Beijing (China); Dept. of Marine Sciences, Texas A and M Univ. at Galveston, Galveston (United States)], e-mail: yxw@tsinghua.edu.cn; Li, Mingwei; Shen, Lulu [Ministry of Education Key Lab. for Earth System Modeling, Center for Earth System Science, Tsinghua Univ., Beijing (China)

    2013-11-15

    Previous studies have indicated that the regression slope between the interhemispheric difference (IHD) of CO{sub 2} mixing ratios and fossil fuel (FF) CO{sub 2} emissions was rather constant at about 0.5 ppm/Pg C yr{sup -1} during 1957 - 2003. In this study, we found that the average regression slopes between the IHD of CO{sub 2} mixing ratios and IHD of FF emissions for 16 sites in the Northern Hemisphere (NH) decreased from 0.69{+-}0.12 ppm/Pg C yr{sup -1} during 1982 - 1991 to 0.37{+-}0.06 ppm/Pg C yr{sup -1} during 1996 - 2008 (IHD of CO{sub 2} defined as the differences between each site and the South Pole, SPO). The largest difference was found in summer and autumn. The change in the spatial distribution of FF emissions driven by fast increasing Asian emissions may explain the slope change at three sites located north of 60 deg N but not at the other sites. A 30-yr SF{sub 6} simulation with time-varying meteorology and constant emissions suggests no significant difference in the decadal average and seasonal variation of interhemispheric exchange time{sub (}t{sub ex)} between the two periods. Based on the hemispheric net carbon fluxes derived from a two-box model, we attributed 75 % of the regression slope decrease at NH sites south of 60 deg N to the acceleration of net carbon sink increase in the NH and 25 % to the weakening of net carbon sink increase in the SH during 1996 - 2008. The growth rate of net carbon sink in the NH has increased by a factor of about three from 0.028{+-}0.023 [mean{+-}2{sigma}] Pg C yr{sup -2} during 1982 - 1991 to 0.093{+-}0.033 Pg C yr{sup -2} during 1996 - 2008, exceeding the percentage increase in the growth rate of IHD of FF emissions between the two periods (45%). The growth rate of net carbon sink in the SH has reduced 62 % from 0.058{+-}0.018 Pg C yr{sup -2} during 1982 - 1991 to 0.022{+-}0.012 Pg C yr{sup -2} during 1996 - 2008.

  9. Atypical inter-hemispheric communication correlates with altered motor inhibition during learning of a new bimanual coordination pattern in developmental coordination disorder.

    Science.gov (United States)

    Blais, Mélody; Amarantini, David; Albaret, Jean-Michel; Chaix, Yves; Tallet, Jessica

    2017-04-25

    Impairment of motor learning skills in developmental coordination disorder (DCD) has been reported in several studies. Some hypotheses on neural mechanisms of motor learning deficits in DCD have emerged but, to date, brain-imaging investigations are scarce. The aim of the present study is to assess possible changes in communication between brain areas during practice of a new bimanual coordination task in teenagers with DCD (n = 10) compared to matched controls (n = 10). Accuracy, stability and number of mirror movements were computed as behavioural variables. Neural variables were assessed by electroencephalographic coherence analyses of intra-hemispheric and inter-hemispheric fronto-central electrodes. In both groups, accuracy of the new coordination increased concomitantly with right intra-hemispheric fronto-central coherence. Compared to typically developing teenagers, DCD teenagers presented learning difficulties expressed by less stability, no stabilization of the new coordination and a greater number of mirror movements despite practice. These measures correlated with reduced inter-hemispheric communication, even after practice of the new coordination. For the first time, these findings provide neuro-imaging evidence of a kind of inter-hemispheric 'disconnection' related to altered inhibition of mirror movements during motor learning in DCD. © 2017 John Wiley & Sons Ltd.

  10. Development of spatial integration depends on top-down and interhemispheric connections that can be perturbed in migraine: a DCM analysis.

    Science.gov (United States)

    Fornari, Eleonora; Rytsar, Romana; Knyazeva, Maria G

    2014-05-01

    In humans, spatial integration develops slowly, continuing through childhood into adolescence. On the assumption that this protracted course depends on the formation of networks with slowly developing top-down connections, we compared effective connectivity in the visual cortex between 13 children (age 7-13) and 14 adults (age 21-42) using a passive perceptual task. The subjects were scanned while viewing bilateral gratings, which either obeyed Gestalt grouping rules [colinear gratings (CG)] or violated them [non-colinear gratings (NG)]. The regions of interest for dynamic causal modeling were determined from activations in functional MRI contrasts stimuli > background and CG > NG. They were symmetrically located in V1 and V3v areas of both hemispheres. We studied a common model, which contained reciprocal intrinsic and modulatory connections between these regions. An analysis of effective connectivity showed that top-down modulatory effects generated at an extrastriate level and interhemispheric modulatory effects between primary visual areas (all inhibitory) are significantly weaker in children than in adults, suggesting that the formation of feedback and interhemispheric effective connections continues into adolescence. These results are consistent with a model in which spatial integration at an extrastriate level results in top-down messages to the primary visual areas, where they are supplemented by lateral (interhemispheric) messages, making perceptual encoding more efficient and less redundant. Abnormal formation of top-down inhibitory connections can lead to the reduction of habituation observed in migraine patients.

  11. Rebmab200, a Humanized Monoclonal Antibody Targeting the Sodium Phosphate Transporter NaPi2b Displays Strong Immune Mediated Cytotoxicity against Cancer: A Novel Reagent for Targeted Antibody Therapy of Cancer

    Science.gov (United States)

    dos Santos, Mariana Lopes; Yeda, Fernanda Perez; Tsuruta, Lilian Rumi; Horta, Bruno Brasil; Pimenta, Alécio A.; Degaki, Theri Leica; Soares, Ibere C.; Tuma, Maria Carolina; Okamoto, Oswaldo Keith; Alves, Venancio A. F.; Ritter, Gerd; Moro, Ana Maria

    2013-01-01

    NaPi2b, a sodium-dependent phosphate transporter, is highly expressed in ovarian carcinomas and is recognized by the murine monoclonal antibody MX35. The antibody had shown excellent targeting to ovarian cancer in several early phase clinical trials but being murine the antibody's full therapeutic potential could not be explored. To overcome this impediment we developed a humanized antibody version named Rebmab200, expressed in human PER.C6® cells and cloned by limiting dilution. In order to select a clone with high therapeutic potential clones were characterized using a series of physicochemical assays, flow cytometry, real-time surface plasmon resonance, glycosylation analyses, immunohistochemistry, antibody-dependent cell-mediated cytotoxicity, complement-dependent-cytotoxicity assays and quantitative PCR. Comparative analyses of Rebmab200 and MX35 monoclonal antibodies demonstrated that the two antibodies had similar specificity for NaPi2b by flow cytometry with a panel of 30 cell lines and maintained similar kinetic parameters. Robust and high producer cell clones potentially suitable for use in manufacturing were obtained. Rebmab200 antibodies were assessed by immunohistochemistry using a large panel of tissues including human carcinomas of ovarian, lung, kidney and breast origin. An assessment of its binding towards 33 normal human organs was performed as well. Rebmab200 showed selected strong reactivity with the tested tumor types but little or no reactivity with the normal tissues tested confirming its potential for targeted therapeutics strategies. The remarkable cytotoxicity shown by Rebmab200 in OVCAR-3 cells is a significant addition to the traits of stability and productivity displayed by the top clones of Rebmab200. Antibody-dependent cell-mediated toxicity functionality was confirmed in repeated assays using cancer cell lines derived from ovary, kidney and lung as targets. To explore use of this antibody in clinical trials, GMP production of Rebmab

  12. Self-regulation of inter-hemispheric visual cortex balance through real-time fMRI neurofeedback training.

    Science.gov (United States)

    Robineau, F; Rieger, S W; Mermoud, C; Pichon, S; Koush, Y; Van De Ville, D; Vuilleumier, P; Scharnowski, F

    2014-10-15

    Recent advances in neurofeedback based on real-time functional magnetic resonance imaging (fMRI) allow for learning to control spatially localized brain activity in the range of millimeters across the entire brain. Real-time fMRI neurofeedback studies have demonstrated the feasibility of self-regulating activation in specific areas that are involved in a variety of functions, such as perception, motor control, language, and emotional processing. In most of these previous studies, participants trained to control activity within one region of interest (ROI). In the present study, we extended the neurofeedback approach by now training healthy participants to control the interhemispheric balance between their left and right visual cortices. This was accomplished by providing feedback based on the difference in activity between a target visual ROI and the corresponding homologue region in the opposite hemisphere. Eight out of 14 participants learned to control the differential feedback signal over the course of 3 neurofeedback training sessions spread over 3 days, i.e., they produced consistent increases in the visual target ROI relative to the opposite visual cortex. Those who learned to control the differential feedback signal were subsequently also able to exert that control in the absence of neurofeedback. Such learning to voluntarily control the balance between cortical areas of the two hemispheres might offer promising rehabilitation approaches for neurological or psychiatric conditions associated with pathological asymmetries in brain activity patterns, such as hemispatial neglect, dyslexia, or mood disorders. Copyright © 2014 Elsevier Inc. All rights reserved.

  13. The loss of asymmetry and reduced interhemispheric connectivity in adolescents with autism: a study using diffusion spectrum imaging tractography.

    Science.gov (United States)

    Lo, Yu-Chun; Soong, Wei-Tsuen; Gau, Susan Shur-Fen; Wu, Yu-Yu; Lai, Meng-Chuan; Yeh, Fang-Cheng; Chiang, Wen-Yang; Kuo, Li-Wei; Jaw, Fu-Shan; Tseng, Wen-Yih Isaac

    2011-04-30

    Evidence from neuroimaging and neurobiological studies suggests that abnormalities in cortical-cortical connectivity involving both local and long-distance scales may be related to autism. The present study analyzed the microstructural integrity of the long-range connectivity related to social cognition and language processing with diffusion tractography among adolescents with autism compared with neurotypical adolescents. Tract-specific analyses were used to study the long-range connectivity responsible for integrating social cognition and language processing. Specifically, three pairs of association fibers and three portions of callosal fiber tracts were analyzed. Generalized fractional anisotropy (GFA) values were measured along individual targeted fiber tracts to investigate alterations in microstructure integrity. The asymmetry patterns were also assessed in three pairs of association fibers. In neurotypical participants, we found a consistent leftward asymmetry in three pairs of association fibers. However, adolescents with autism did not demonstrate such asymmetry. Moreover, adolescents with autism had significantly lower mean GFA in three callosal fiber tracts than neurotypical participants. The loss of leftward asymmetry and reduction of interhemispheric connection in adolescents with autism suggest alterations of the long-range connectivity involved in social cognition and language processing. Our results warrant further investigation by combining developmental and neurocognitive data. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

  14. A greater involvement of posterior brain areas in interhemispheric transfer in autism: fMRI, DWI and behavioral evidences

    Directory of Open Access Journals (Sweden)

    Elise B. Barbeau

    2015-01-01

    Full Text Available A small corpus callosum (CC is one of the most replicated neurobiological findings in autism spectrum (AS. However, its effect on interhemispheric (IH communication is unknown. We combined structural (CC area and DWI, functional (task-related fMRI activation and connectivity analyses as well as behavioral (Poffenberger and Purdue tasks measures to investigate IH integration in adult AS individuals of typical intelligence. Despite similar behavioral IH transfer time and performances in bimanual tasks, the CC sub-regions connecting frontal and parietal cortical areas were smaller in AS than in non-AS individuals, while those connecting visual regions were similar. The activation of visual areas was lower in AS than in non-AS individuals during the presentation of visual stimuli. Behavioral IH performances were related to the properties of CC subregions connecting motor areas in non-AS individuals, but to the properties of posterior CC regions in AS individuals. Furthermore, there was greater functional connectivity between visual areas in the AS than in the non-AS group. Levels of connectivity were also stronger in visual than in motor regions in the autistic subjects, while the opposite was true for the non-autistic group. Thus, visual IH transfer plays an important role in visuo-motor tasks in AS individuals. These findings extend the well established enhanced role of perception in autistic cognition to visuo-motor IH information transfer.

  15. Non-uniform interhemispheric temperature trends over the past 550 years

    Energy Technology Data Exchange (ETDEWEB)

    Duncan, Richard P. [Landcare Research, PO Box 40, Lincoln (New Zealand); Lincoln University, Bio-Protection Research Centre, PO Box 84, Lincoln (New Zealand); Fenwick, Pavla; Palmer, Jonathan G. [Gondwana Tree-ring Laboratory, PO Box 14, Canterbury (New Zealand); McGlone, Matt S. [Landcare Research, PO Box 40, Lincoln (New Zealand); Turney, Chris S.M. [University of Exeter, School of Geography, Exeter (United Kingdom)

    2010-12-15

    The warming trend over the last century in the northern hemisphere (NH) was interrupted by cooling from ad 1940 to 1975, a period during which the southern hemisphere experienced pronounced warming. The cause of these departures from steady warming at multidecadal timescales are unclear; the prevailing explanation is that they are driven by non-uniformity in external forcings but recent models suggest internal climate drivers may play a key role. Paleoclimate datasets can help provide a long-term perspective. Here we use tree-rings to reconstruct New Zealand mean annual temperature over the last 550 years and demonstrate that this has frequently cycled out-of-phase with NH mean annual temperature at a periodicity of around 30-60 years. Hence, observed multidecadal fluctuations around the recent warming trend have precedents in the past, strongly implicating natural climate variation as their cause. We consider the implications of these changes in understanding and modelling future climate change. (orig.)

  16. Strongly Correlated Topological Insulators

    Science.gov (United States)

    2016-02-03

    Strongly Correlated Topological Insulators In the past year, the grant was used for work in the field of topological phases, with emphasis on finding...surface of topological insulators. In the past 3 years, we have started a new direction, that of fractional topological insulators. These are materials...in which a topologically nontrivial quasi-flat band is fractionally filled and then subject to strong interactions. The views, opinions and/or

  17. Strong Cosmic Censorship

    Science.gov (United States)

    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. Changes in cerebellar activity and inter-hemispheric coherence accompany improved reading performance following Quadrato Motor Training.

    Science.gov (United States)

    Ben-Soussan, Tal Dotan; Avirame, Keren; Glicksohn, Joseph; Goldstein, Abraham; Harpaz, Yuval; Ben-Shachar, Michal

    2014-01-01

    Dyslexia is a multifactorial reading deficit that involves multiple brain systems. Among other theories, it has been suggested that cerebellar dysfunction may be involved in dyslexia. This theory has been supported by findings from anatomical and functional imaging. A possible rationale for cerebellar involvement in dyslexia could lie in the cerebellum's role as an oscillator, producing synchronized activity within neuronal networks including sensorimotor networks critical for reading. If these findings are causally related to dyslexia, a training regimen that enhances cerebellar oscillatory activity should improve reading performance. We examined the cognitive and neural effects of Quadrato Motor Training (QMT), a structured sensorimotor training program that involves sequencing of motor responses based on verbal commands. Twenty-two adult Hebrew readers (12 dyslexics and 10 controls) were recruited for the study. Using Magnetoencephalography (MEG), we measured changes in alpha power and coherence following QMT in a within-subject design. Reading performance was assessed pre- and post-training using a comprehensive battery of behavioral tests. Our results demonstrate improved performance on a speeded reading task following one month of intensive QMT in both the dyslexic and control groups. Dyslexic participants, but not controls, showed significant increase in cerebellar oscillatory alpha power following training. In addition, across both time points, inter-hemispheric alpha coherence was higher in the dyslexic group compared to the control group. In conclusion, the current findings suggest that the combination of motor and language training embedded in QMT increases cerebellar oscillatory activity in dyslexics and improves reading performance. These results support the hypothesis that the cerebellum plays a role in skilled reading, and begin to unravel the underlying mechanisms that mediate cerebellar contribution in cognitive and neuronal augmentation.

  19. Magnetoencephalographic evidence of the interhemispheric asymmetry in echoic memory lifetime and its dependence on handedness and gender.

    Science.gov (United States)

    Ioannides, Andreas A; Popescu, Mihai; Otsuka, Asuka; Bezerianos, Anastasios; Liu, Lichan

    2003-07-01

    The echoic memory trace (EMT) refers to neuronal activity associated with the short-term retention of stimulus-related information, especially within the primary and association auditory cortex. Using magnetoencephalography it is possible to determine quantitatively the lifetime of the EMT. Previous studies assumed that each new stimulus drives the EMT to its full strength, which then passively decays. In this study we show the limitations of this assumption using trains of auditory stimuli designed specifically for computing the EMT lifetime and its contextual sensitivity. We estimated a time-dependent EMT using a data-driven approach, which allows contributions from a relatively wide area around the auditory cortex in our quantitative measures. We identified: (1) internally generated cortical activations during the silent period between stimuli well separated in time from each other, which had influence on the morphology of the neuromagnetic response to the next external stimulus; and (2) EMTs with different lifetimes that modulate the amplitude of the evoked responses at different latencies, suggesting the existence of multiple neural delay lines. Long EMT lifetimes were observed on the descending part of the M100 complex, which showed handedness and gender-dependent interhemispheric asymmetry. Specifically, all subjects showed longer EMT lifetimes on the left hemisphere, except left-handed males. Distributed source analysis of the data for one left- and one right-handed male subject identified a secondary generator in the right-handed subject, which was located posterior to the early primary generator and dominated the auditory response at late latencies, where EMT lifetime asymmetry was high. The identified multiple neural delay lines and their laterality may provide a link between macroneuronal activity and left hemisphere specialization for processing linguistic material.

  20. Heavily T2 weighted MR assessment of fornical injury after anterior interhemispheric approach for large suprasellar tumors

    International Nuclear Information System (INIS)

    Saeki, N.; Kubota, M.; Murai, H.; Yamaura, A.; Sunami, K.; Uozumi, A.

    2001-01-01

    Fornical injury in transforaminal approach is well known. Its injury in the anterior interhemispheric approach (AIA) has been rarely highlighted. We report 2 cases with a large suprasellar tumor who underwent AIA. Postoperative heavily T2 weighted reversed (T2R) MR images demonstrated its unilateral injury. The clinical significance of symptom-free fornical injury after AIA is discussed. Cases 1 and 2 were a 15 year-old girl with a meningioma and a 49-year-old woman with a craniopharyngioma, respectively. They underwent AIA. Postoperative T2R images revealed unilateral fornical crus atrophy. They did not present associated memory deficits. Case 1 had the injury of both fornical column and anterior commissure. They were speculatively torn by intra-operative lateral retraction of the frontal lobes. Case 2 had unilateral atrophy of the mammillary body and postcommissural fornix, which were probably caused by ischemic damage related to surgical manipulation, since case 2 had an associated anterior thalamic infarct. During the Operation for large suprasellar tumors, excessive laterally directed brain retraction should be avoided, since such manipulation may easily tear the overstretched anterior commissure and fornical column. Once we notice or suspect fornical injury an MR studies in cases of re-operation, we have to choose a surgical approach and operative manipulation to preserve an intact fornix. The MR evaluation of fornix should be included in the peri-operative radiological assessment, since patients with unilateral fornical injury were free of memory disturbance, and T2R imaging is a useful MR sequence for depicting the anatomy related to the fornix. (author)

  1. Sensitivity of the tropical climate to an interhemispheric thermal gradient: the role of tropical ocean dynamics

    Science.gov (United States)

    Talento, Stefanie; Barreiro, Marcelo

    2018-03-01

    This study aims to determine the role of the tropical ocean dynamics in the response of the climate to extratropical thermal forcing. We analyse and compare the outcomes of coupling an atmospheric general circulation model (AGCM) with two ocean models of different complexity. In the first configuration the AGCM is coupled with a slab ocean model while in the second a reduced gravity ocean (RGO) model is additionally coupled in the tropical region. We find that the imposition of extratropical thermal forcing (warming in the Northern Hemisphere and cooling in the Southern Hemisphere with zero global mean) produces, in terms of annual means, a weaker response when the RGO is coupled, thus indicating that the tropical ocean dynamics oppose the incoming remote signal. On the other hand, while the slab ocean coupling does not produce significant changes to the equatorial Pacific sea surface temperature (SST) seasonal cycle, the RGO configuration generates strong warming in the central-eastern basin from April to August balanced by cooling during the rest of the year, strengthening the seasonal cycle in the eastern portion of the basin. We hypothesize that such changes are possible via the dynamical effect that zonal wind stress has on the thermocline depth. We also find that the imposed extratropical pattern affects El Niño-Southern Oscillation, weakening its amplitude and low-frequency behaviour.

  2. Paleoclimatic and Paleoceanographic Holocene Sedimentary Records in the Gulf of California - Eastern Pacific Ocean Interhemispheric Connections

    Science.gov (United States)

    Perez-Cruz, L.; Urrutia-Fucugauchi, J.

    2009-05-01

    Initial results of a study on the distribution, thickness and stratigraphy of the sedimentary sequences in the Gulf of California are presented. The Gulf is an elongated narrow young oceanic basin bordered by the Baja California peninsula and mainland Mexico. The Gulf extends over 1200 km across the Tropic of Cancer from the tropical to the temperate zones, surrounded by arid and semi-arid regions, including the Sonora-Mojave Desert. Paleoceanographic conditions are dominated by water exchange at the Gulf mouth and water masses changes along the Gulf. Tectonic basins reach down in excess of 3000 m depths and get shallower to the north. Here we focus on the Holocene sediment sequences in the southern sector, which contains several marginal and central anoxic basins that constitute rich archives of paleoclimatic and paleoenvironmental evolution for the past 3.6 Ma. In the mouth area, main sources of sediments are silicic volcanic and intrusive rocks in the Baja peninsula and mainland, including Los Cabos and Puerto Vallarta batholiths. Fine-grained eolian dusts, pluvial and biogenic sediments are present in the sediment cores in the Gulf basins such as La Paz, Alfonso, Carmen, Pescadero and Guaymas basins. Turbiditic currents and tephra deposits also occur in the cores. Paleoclimatic records show the influences of regional processes, including the ENSO and PDO signals marked by drought and increased precipitation phases. Relative distribution and thickness of sediments at the mouth of the Gulf correlate with bathymetry and location with respect to spreading center, transform faults and margins of the peninsula and mainland Mexico. Rock magnetic core scans and mineralogy at few locations are available, which allow inferences on sediment sources, transport and deposition processes, diagenesis, paleoceanographic and paleoclimatic evolution for the Holocene.

  3. Strong Arcwise Connectedness

    OpenAIRE

    Espinoza, Benjamin; Gartside, Paul; Kovan-Bakan, Merve; Mamatelashvili, Ana

    2012-01-01

    A space is `n-strong arc connected' (n-sac) if for any n points in the space there is an arc in the space visiting them in order. A space is omega-strong arc connected (omega-sac) if it is n-sac for all n. We study these properties in finite graphs, regular continua, and rational continua. There are no 4-sac graphs, but there are 3-sac graphs and graphs which are 2-sac but not 3-sac. For every n there is an n-sac regular continuum, but no regular continuum is omega-sac. There is an omega-sac ...

  4. Abortion: Strong's counterexamples fail

    DEFF Research Database (Denmark)

    Di Nucci, Ezio

    2009-01-01

    This paper shows that the counterexamples proposed by Strong in 2008 in the Journal of Medical Ethics to Marquis's argument against abortion fail. Strong's basic idea is that there are cases--for example, terminally ill patients--where killing an adult human being is prima facie seriously morally......'s scenarios have some valuable future or admitted that killing them is not seriously morally wrong. Finally, if "valuable future" is interpreted as referring to objective standards, one ends up with implausible and unpalatable moral claims....

  5. A strong comeback

    International Nuclear Information System (INIS)

    Marier, D.

    1992-01-01

    This article presents the results of a financial rankings survey which show a strong economic activity in the independent energy industry. The topics of the article include advisor turnover, overseas banks, and the increase in public offerings. The article identifies the top project finance investors for new projects and restructurings and rankings for lenders

  6. Strong Electroweak Symmetry Breaking

    CERN Document Server

    Grinstein, Benjamin

    2011-01-01

    Models of spontaneous breaking of electroweak symmetry by a strong interaction do not have fine tuning/hierarchy problem. They are conceptually elegant and use the only mechanism of spontaneous breaking of a gauge symmetry that is known to occur in nature. The simplest model, minimal technicolor with extended technicolor interactions, is appealing because one can calculate by scaling up from QCD. But it is ruled out on many counts: inappropriately low quark and lepton masses (or excessive FCNC), bad electroweak data fits, light scalar and vector states, etc. However, nature may not choose the minimal model and then we are stuck: except possibly through lattice simulations, we are unable to compute and test the models. In the LHC era it therefore makes sense to abandon specific models (of strong EW breaking) and concentrate on generic features that may indicate discovery. The Technicolor Straw Man is not a model but a parametrized search strategy inspired by a remarkable generic feature of walking technicolor,...

  7. Enhanced gravity-wave activity and interhemispheric coupling during the MaCWAVE/MIDAS northern summer program 2002

    Directory of Open Access Journals (Sweden)

    E. Becker

    2006-07-01

    Full Text Available We present new sensitivity experiments that link observed anomalies of the mesosphere and lower thermosphere at high latitudes during the MaCWAVE/MIDAS summer program 2002 to enhanced planetary Rossby-wave activity in the austral winter troposphere.

    We employ the same general concept of a GCM having simplified representations of radiative and latent heating as in a previous study by Becker et al. (2004. In the present version, however, the model includes no gravity wave (GW parameterization. Instead we employ a high vertical and a moderate horizontal resolution in order to describe GW effects explicitly. This is supported by advanced, nonlinear momentum diffusion schemes that allow for a self-consistent generation of inertia and mid-frequency GWs in the lower atmosphere, their vertical propagation into the mesosphere and lower thermosphere, and their subsequent dissipation which is induced by prescribed horizontal and vertical mixing lengths as functions of height.

    The main anomalies in northern summer 2002 consist of higher temperatures than usual above 82 km, an anomalous eastward mean zonal wind between 70 and 90 km, an altered meridional flow, enhanced turbulent dissipation below 80 km, and enhanced temperature variations associated with GWs. These signals are all reasonably described by differences between two long-integration perpetual model runs, one with normal July conditions, and another run with modified latent heating in the tropics and Southern Hemisphere to mimic conditions that correspond to the unusual austral winter 2002. The model response to the enhanced winter hemisphere Rossby-wave activity has resulted in both an interhemispheric coupling through a downward shift of the GW-driven branch of the residual circulation and an increased GW activity at high summer latitudes. Thus a quantitative explanation of the dynamical state of the northern mesosphere and lower

  8. Plasmons in strong superconductors

    International Nuclear Information System (INIS)

    Baldo, M.; Ducoin, C.

    2011-01-01

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

  9. PREFACE: Strongly correlated electron systems Strongly correlated electron systems

    Science.gov (United States)

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

    2012-07-01

    make use of 'small' electrons packed to the highest possible density. These are by definition 'strongly correlated'. For example: good photovoltaics must be efficient optical absorbers, which means that photons will generate tightly bound electron-hole pairs (excitons) that must then be ionised at a heterointerface and transported to contacts; efficient solid state refrigeration depends on substantial entropy changes in a unit cell, with large local electrical or magnetic moments; efficient lighting is in a real sense the inverse of photovoltaics; the limit of an efficient battery is a supercapacitor employing mixed valent ions; fuel cells and solar to fuel conversion require us to understand electrochemistry on the scale of a single atom; and we already know that the only prospect for effective high temperature superconductivity involves strongly correlated materials. Even novel IT technologies are now seen to have value not just for novel function but also for efficiency. While strongly correlated electron systems continue to excite researchers and the public alike due to the fundamental science issues involved, it seems increasingly likely that support for the science will be leveraged by its impact on energy and sustainability. Strongly correlated electron systems contents Strongly correlated electron systemsSiddharth S Saxena and P B Littlewood Magnetism, f-electron localization and superconductivity in 122-type heavy-fermion metalsF Steglich, J Arndt, O Stockert, S Friedemann, M Brando, C Klingner, C Krellner, C Geibel, S Wirth, S Kirchner and Q Si High energy pseudogap and its evolution with doping in Fe-based superconductors as revealed by optical spectroscopyN L Wang, W Z Hu, Z G Chen, R H Yuan, G Li, G F Chen and T Xiang Structural investigations on YbRh2Si2: from the atomic to the macroscopic length scaleS Wirth, S Ernst, R Cardoso-Gil, H Borrmann, S Seiro, C Krellner, C Geibel, S Kirchner, U Burkhardt, Y Grin and F Steglich Confinement of chiral magnetic

  10. Strong-coupling approximations

    International Nuclear Information System (INIS)

    Abbott, R.B.

    1984-03-01

    Standard path-integral techniques such as instanton calculations give good answers for weak-coupling problems, but become unreliable for strong-coupling. Here we consider a method of replacing the original potential by a suitably chosen harmonic oscillator potential. Physically this is motivated by the fact that potential barriers below the level of the ground-state energy of a quantum-mechanical system have little effect. Numerically, results are good, both for quantum-mechanical problems and for massive phi 4 field theory in 1 + 1 dimensions. 9 references, 6 figures

  11. Strong interaction and QFD

    International Nuclear Information System (INIS)

    Ebata, T.

    1981-01-01

    With an assumed weak multiplet structure for bosonic hadrons, which is consistent with the ΔI = 1/2 rule, it is shown that the strong interaction effective hamiltonian is compatible with the weak SU(2) x U(1) gauge transformation. Especially the rho-meson transforms as a triplet under SU(2)sub(w), and this is the origin of the rho-photon analogy. It is also shown that the existence of the non-vanishing Cabibbo angle is a necessary condition for the absence of the exotic hadrons. (orig.)

  12. Strong Coupling Holography

    CERN Document Server

    Dvali, Gia

    2009-01-01

    We show that whenever a 4-dimensional theory with N particle species emerges as a consistent low energy description of a 3-brane embedded in an asymptotically-flat (4+d)-dimensional space, the holographic scale of high-dimensional gravity sets the strong coupling scale of the 4D theory. This connection persists in the limit in which gravity can be consistently decoupled. We demonstrate this effect for orbifold planes, as well as for the solitonic branes and string theoretic D-branes. In all cases the emergence of a 4D strong coupling scale from bulk holography is a persistent phenomenon. The effect turns out to be insensitive even to such extreme deformations of the brane action that seemingly shield 4D theory from the bulk gravity effects. A well understood example of such deformation is given by large 4D Einstein term in the 3-brane action, which is known to suppress the strength of 5D gravity at short distances and change the 5D Newton's law into the four-dimensional one. Nevertheless, we observe that the ...

  13. [Dreams and interhemispheric asymmetry].

    Science.gov (United States)

    Korabel'nikova, E A; Golubev, V L

    2001-01-01

    The dreams of 103 children and adolescents, aged 10-17 years, have been studied. The test group included 78 patients with neurotic disorders; control one consisted of 25 healthy subjects. Dream features, which were common for those with preferentially left asymmetry profile both in patients as well as in healthy subjects, were: less expressed novelty factor and frequent appearance of rare phenomena, such as "déjà vu in wakefulness", reality, "mixed" (overlapped) dreams, prolonged dreams in repeat sleep, frequent changes of personages and scenes of action. Left-hander dream peculiarities, being detected only in neurotic patients but not in healthy subjects, emerged as lucid phenomena deficit, "dream in dreams" and "dream reminiscence in dream" syndrome, which have been found only in left-handers. Right and left hemispheres seem to contribute in different ways to a dream formation. In authors believe that the left hemisphere seems to provide dream origin while the right hemisphere provides dream vividness, figurativeness and affective activation level.

  14. LIGO: The strong belief

    CERN Multimedia

    Antonella Del Rosso

    2016-01-01

    Twenty years of designing, building and testing a number of innovative technologies, with the strong belief that the endeavour would lead to a historic breakthrough. The Bulletin publishes an abstract of the Courier’s interview with Barry Barish, one of the founding fathers of LIGO.   The plots show the signals of gravitational waves detected by the twin LIGO observatories at Livingston, Louisiana, and Hanford, Washington. (Image: Caltech/MIT/LIGO Lab) On 11 February, the Laser Interferometer Gravitational-Wave Observatory (LIGO) and Virgo collaborations published a historic paper in which they showed a gravitational signal emitted by the merger of two black holes. These results come after 20 years of hard work by a large collaboration of scientists operating the two LIGO observatories in the US. Barry Barish, Linde Professor of Physics, Emeritus at the California Institute of Technology and former Director of the Global Design Effort for the Internat...

  15. John Strong (1941 - 2006)

    CERN Multimedia

    Wickens, F

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

  16. Stirring Strongly Coupled Plasma

    CERN Document Server

    Fadafan, Kazem Bitaghsir; Rajagopal, Krishna; Wiedemann, Urs Achim

    2009-01-01

    We determine the energy it takes to move a test quark along a circle of radius L with angular frequency w through the strongly coupled plasma of N=4 supersymmetric Yang-Mills (SYM) theory. We find that for most values of L and w the energy deposited by stirring the plasma in this way is governed either by the drag force acting on a test quark moving through the plasma in a straight line with speed v=Lw or by the energy radiated by a quark in circular motion in the absence of any plasma, whichever is larger. There is a continuous crossover from the drag-dominated regime to the radiation-dominated regime. In the crossover regime we find evidence for significant destructive interference between energy loss due to drag and that due to radiation as if in vacuum. The rotating quark thus serves as a model system in which the relative strength of, and interplay between, two different mechanisms of parton energy loss is accessible via a controlled classical gravity calculation. We close by speculating on the implicati...

  17. Strong-interaction nonuniversality

    International Nuclear Information System (INIS)

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

    1989-01-01

    The universal QCD color theory is extended to an SU(3) 1 direct product SU(3) 2 direct product SU(3) 3 gauge theory, where quarks of the ith generation transform as triplets under SU(3)/sub i/ and singlets under the other two factors. The usual color group is then identified with the diagonal subgroup, which remains exact after symmetry breaking. The gauge bosons associated with the 16 broken generators then form two massive octets under ordinary color. The interactions between quarks and these heavy gluonlike particles are explicitly nonuniversal and thus an exploration of their physical implications allows us to shed light on the fundamental issue of strong-interaction universality. Nonuniversality and weak flavor mixing are shown to generate heavy-gluon-induced flavor-changing neutral currents. The phenomenology of these processes is studied, as they provide the major experimental constraint on the extended theory. Three symmetry-breaking scenarios are presented. The first has color breaking occurring at the weak scale, while the second and third divorce the two scales. The third model has the interesting feature of radiatively induced off-diagonal Kobayashi-Maskawa matrix elements

  18. Radioactive materials transport

    International Nuclear Information System (INIS)

    Talbi, B.

    1996-01-01

    The development of peaceful applications of nuclear energy results in the increase of transport operations of radioactive materials. Therefore strong regulations on transport of radioactive materials turns out to be a necessity in Tunisia. This report presents the different axes of regulations which include the means of transport involved, the radiation protection of the carriers, the technical criteria of security in transport, the emergency measures in case of accidents and penalties in case of infringement. (TEC). 12 refs., 1 fig

  19. Chemical Processing and Transport in the Stratospheric Vortex and Subvortex from Satellite Measurements and Modeling

    Science.gov (United States)

    Santee, Michelle; Manney, Gloria; MacKenzie, Ian; Chipperfield, Martyn; Feng, Wuhu; Sander, Stanley; Froidevaux, Lucien; Livesey, Nathaniel; Bernath, Peter; Walker, Kaley; Boone, Chris

    A suite of atmospheric composition measurements from the Microwave Limb Sounder (MLS) on NASA's Aura satellite and the Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS) on Canada's SCISAT-1 mission is used to study chemical processing in and dispersal of chemically-processed air from the lower stratospheric polar vortices. In particular, interannual and interhemispheric variability in chlorine activation and deactivation are investigated using measurements of ClO, HCl, and ClONO2. Theoretical understanding is assessed by comparing measurements to customized runs of the SLIMCAT 3D chemical transport model. Results are shown from a newly-updated version of the model that incorporates a sophisticated microphysical scheme as a fully-coupled module, allowing polar stratospheric cloud formation and sedimentation to be calculated interactively in full-chemistry simulations. The impact of recently-published ClOOCl absorption cross sections, which yield a stratospheric ClOOCl photolysis rate substantially lower than previous estimates, on the agreement between modelled and measured chlorine species is evaluated. In addition, measurements of HNO3 and O3 and SLIMCAT results are related to mixing diagnostics to track the springtime export of denitrified, ozone-depleted air from the "subvortex", the transition zone (potential temperatures of 350-450 K) between the region above of strong confinement inside the polar vortex and the region below of less restricted exchange with lower-latitude air. Particularly over Antarctica, such mixing of processed air out of the subvortex may significantly affect the composition of the midlatitude lowermost stratosphere and upper troposphere.

  20. EDITORIAL: Strongly correlated electron systems Strongly correlated electron systems

    Science.gov (United States)

    Ronning, Filip; Batista, Cristian

    2011-03-01

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

  1. Theories of inter-hemispheric interactions in aphasia: the role of tDCS in rehabilitation of post-stroke aphasia

    Directory of Open Access Journals (Sweden)

    Roy H Hamilton

    2014-04-01

    Full Text Available Mounting data from behavioral and neuroimaging studies have shown that the process of recovery from aphasia is largely driven by the reorganization of brain networks related to language. Evidence implicates a variety of potential mechanisms in this reorganization, some of which involve substantive changes in brain functional activity within and between cerebral hemispheres. These changes include intrahemispheric recruitment of perilesional left-hemisphere regions and transcallosal interhemispheric interactions between lesioned left-hemisphere language areas and homologous regions in the right hemisphere. With respect to the role of the right hemisphere, it is debated whether interhemispheric interactions are beneficial or deleterious to recovering language networks. Recent years have also seen the emergence of noninvasive brain stimulation techniques such as transcranial magnetic stimulation (TMS and transcranial direct current stimulation (tDCS as potential novel treatments for post-stroke aphasia. Because these techniques are predicated on either focal excitation or inhibition of brain areas, characterization of the functional roles of the left and right hemispheres and transcallosal interactions in aphasia recovery is of central importance to the development and refinement of stimulation-based therapies. However, most treatment studies involving noninvasive brain stimulation in aphasia have tacitly accepted the interhemispheric inhibition model, in which right hemisphere activity interferes with language recovery that is mediated by left hemisphere perisylvian regions. Based on this account, many studies in aphasia involving TMS and tDCS have adopted one of two approaches consistent with the model: left hemisphere excitation or right hemisphere inhibition. In this presentation, we will review both clinical and cognitive neuroscience evidence that elucidates different hemispheric mechanisms that influence recovery from aphasia after stroke

  2. Quantum electrodynamics of strong fields

    International Nuclear Information System (INIS)

    Greiner, W.

    1983-01-01

    Quantum Electrodynamics of Strong Fields provides a broad survey of the theoretical and experimental work accomplished, presenting papers by a group of international researchers who have made significant contributions to this developing area. Exploring the quantum theory of strong fields, the volume focuses on the phase transition to a charged vacuum in strong electric fields. The contributors also discuss such related topics as QED at short distances, precision tests of QED, nonperturbative QCD and confinement, pion condensation, and strong gravitational fields In addition, the volume features a historical paper on the roots of quantum field theory in the history of quantum physics by noted researcher Friedrich Hund

  3. Strong Josephson Coupling in Planar Graphene Junctions

    Science.gov (United States)

    Park, Jinho; Lee, Gil-Ho; Lee, Jae Hyeong; Takane, Yositake; Imura, Ken-Ichiro; Taniguchi, Takashi; Watanabe, Kenji; Lee, Hu-Jong

    A recent breakthrough of processing graphene, employing encapsulation by hexagonal boron nitride layers (BGB structure), allows realizing the ballistic carrier transport in graphene. Thereafter, ballistic Josephson coupling has been studied by closely edge-contacted BGB structure with two superconducting electrodes. Here, we report on the strong Josephson coupling with planar graphene junction in truly short and ballistic regime. Our device showed high transmission probability and the junction critical current (IC) oscillating for sweeping the gate voltage along with the normal conductance oscillation (Fabry-Perot oscillations), providing a direct evidence for the ballistic nature of the junction pair current. We also observed the convex-upward shape of decreasing critical currents with increasing temperature, canonical properties of the short Josephson coupling. By fitting these curves into theoretical models, we demonstrate the strong Josephson coupling in our devices, which is also supported by the exceptionally large value of ICRN ( 2 Δ / e RNis the normal resistance).

  4. Reappraising contemporary theories of subcortical participation in language: proposing an interhemispheric regulatory function for the subthalamic nucleus (STN) in the mediation of high-level linguistic processes.

    Science.gov (United States)

    Whelan, Brooke-Mai; Murdoch, Bruce E; Theodoros, Deborah G; Silburn, Peter; Hall, Bruce

    2004-02-01

    Apropos the basal ganglia, the dominant striatum and globus pallidus internus (GPi) have been hypothesised to represent integral components of subcortical language circuitry. Working subcortical language theories, however, have failed thus far to consider a role for the STN in the mediation of linguistic processes, a structure recently defined as the driving force of basal ganglia output. The aim of this research was to investigate the impact of surgically induced functional inhibition of the STN upon linguistic abilities, within the context of established models of basal ganglia participation in language. Two males with surgically induced 'lesions' of the dominant and non-dominant dorsolateral STN, aimed at relieving Parkinsonian motor symptoms, served as experimental subjects. General and high-level language profiles were compiled for each subject up to 1 month prior to and 3 months following neurosurgery, within the drug-on state (i.e., when optimally medicated). Comparable post-operative alterations in linguistic performance were observed subsequent to surgically induced functional inhibition of the left and right STN. More specifically, higher proportions of reliable decline as opposed to improvement in post-operative performance were demonstrated by both subjects on complex language tasks, hypothesised to entail the interplay of cognitive-linguistic processes. The outcomes of the current research challenge unilateralised models of functional basal ganglia organisation with the proposal of a potential interhemispheric regulatory function for the STN in the mediation of high-level linguistic processes.

  5. Electromotive force in strongly compressible magnetohydrodynamic turbulence

    Science.gov (United States)

    Yokoi, N.

    2017-12-01

    Variable density fluid turbulence is ubiquitous in geo-fluids, not to mention in astrophysics. Depending on the source of density variation, variable density fluid turbulence may be divided into two categories: the weak compressible (entropy mode) turbulence for slow flow and the strong compressible (acoustic mode) turbulence for fast flow. In the strong compressible turbulence, the pressure fluctuation induces a strong density fluctuation ρ ', which is represented by the density variance ( denotes the ensemble average). The turbulent effect on the large-scale magnetic-field B induction is represented by the turbulent electromotive force (EMF) (u': velocity fluctuation, b': magnetic-field fluctuation). In the usual treatment in the dynamo theory, the expression for the EMF has been obtained in the framework of incompressible or weak compressible turbulence, where only the variation of the mean density , if any, is taken into account. We see from the equation of the density fluctuation ρ', the density variance is generated by the large mean density variation ∂ coupled with the turbulent mass flux . This means that in the region where the mean density steeply changes, the density variance effect becomes relevant for the magnetic field evolution. This situation is typically the case for phenomena associated with shocks and compositional discontinuities. With the aid of the analytical theory of inhomogeneous compressible magnetohydrodynamic (MHD) turbulence, the expression for the turbulent electromotive force is investigated. It is shown that, among others, an obliqueness (misalignment) between the mean density gradient ∂ and the mean magnetic field B may contribute to the EMF as ≈χ B×∂ with the turbulent transport coefficient χ proportional to the density variance (χ ). This density variance effect is expected to strongly affect the EMF near the interface, and changes the transport properties of turbulence. In the case of an interface under the MHD slow

  6. Strong WW Interaction at LHC

    Energy Technology Data Exchange (ETDEWEB)

    Pelaez, Jose R

    1998-12-14

    We present a brief pedagogical introduction to the Effective Electroweak Chiral Lagrangians, which provide a model independent description of the WW interactions in the strong regime. When it is complemented with some unitarization or a dispersive approach, this formalism allows the study of the general strong scenario expected at the LHC, including resonances.

  7. The Shape of Strongly Disturbed Dayside Magnetopause

    Directory of Open Access Journals (Sweden)

    Alexei V. Dmitriev Alla V. Suvorova

    2013-01-01

    Full Text Available During strong geomagnetic disturbances, the Earth¡¦s magnetosphere exhibits unusual and nonlinear interaction with the incident flow of magnetized solar wind plasma. Global Magneto-hydro-dynamic (MHD modeling of the magnetosphere predicts that the storm-time effects at the magnetopause result from the abnormal plasma transport and/or extremely strong field aligned currents. In-situ observations of the magnetospheric boundary, magnetopause, by Geosynchronous Operational Environmental Satellite (GOES allowed us to find experimentally such effects as a saturation of the dayside reconnection, unusual bluntness and prominent duskward skewing of the nose magnetopause. The saturation and duskward skewing were attributed to the storm-time magnetopause formation under strong southward interplanetary magnetic field (IMF. The unusual bluntness was observed during both high solar wind pressure and strong southward IMF. We suggest that these phenomena are caused by a substantial contribution of the cross-tail current magnetic field and the hot magnetospheric plasma from the asymmetrical ring current into the pressure balance at the dayside magnetopause.

  8. Strong-back safety latch

    International Nuclear Information System (INIS)

    DeSantis, G.N.

    1995-01-01

    The calculation decides the integrity of the safety latch that will hold the strong-back to the pump during lifting. The safety latch will be welded to the strong-back and will latch to a 1.5-in. dia cantilever rod welded to the pump baseplate. The static and dynamic analysis shows that the safety latch will hold the strong-back to the pump if the friction clamps fail and the pump become free from the strong-back. Thus, the safety latch will meet the requirements of the Lifting and Rigging Manual for under the hook lifting for static loading; it can withstand shock loads from the strong-back falling 0.25 inch

  9. Strong-back safety latch

    Energy Technology Data Exchange (ETDEWEB)

    DeSantis, G.N.

    1995-03-06

    The calculation decides the integrity of the safety latch that will hold the strong-back to the pump during lifting. The safety latch will be welded to the strong-back and will latch to a 1.5-in. dia cantilever rod welded to the pump baseplate. The static and dynamic analysis shows that the safety latch will hold the strong-back to the pump if the friction clamps fail and the pump become free from the strong-back. Thus, the safety latch will meet the requirements of the Lifting and Rigging Manual for under the hook lifting for static loading; it can withstand shock loads from the strong-back falling 0.25 inch.

  10. Macropores and macropore transport

    DEFF Research Database (Denmark)

    Iversen, Bo Vangsø; Lamandé, Mathieu; Torp, Søren Bent

    2012-01-01

    Preferential transport of water through soil macropores is a governing process in the facilitated transport of strongly sorbing compounds. The aim of this study was to investigate the relationships between macropore density and the hydraulic conductivity of the soil and to test the sampling...

  11. Titanium: light, strong, and white

    Science.gov (United States)

    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.

  12. The concept of transcortical cell assemblies: a key to the understanding of cortical lateralization and interhemispheric interaction.

    Science.gov (United States)

    Pulvermüller, F; Mohr, B

    1996-01-01

    According to Hebb, elements of higher cognitive processes, such as concepts, words and mental images, are realized in the brain as cortical cell assemblies, i.e. large and strongly connected neuron populations that form functional units. Neurons belonging to such assemblies may be scattered over wide cortical areas, and some cell assemblies may even comprise neurons of both hemispheres (transcortical assemblies). If full activation (ignition) of an assembly leads to fast circulation of neuronal activity in the assembly, this process should be visible in high-frequency cortical responses. Some evidence will be reviewed that cell assembly ignition indeed leads to changes in high-frequency cortical responses which can be recorded in the EEG and MEG. Within the cell assembly-framework, the question of cortical laterality translates into the question of how neurons of transcortical assemblies are balanced between the hemispheres. This approach allows for different degrees of laterality. Recent evidence is summarized that the degree of laterality indeed differs between language units. For example, the cortical representation of certain words appears to be strongly lateralized to the left hemisphere while those of others are less lateralized. If neurons of both hemispheres are part of one assembly bihemispheric processing should lead to a processing advantage compared to processing in the dominant hemisphere alone. The latter appears to be the case for lexical processing, as revealed by recent behavioral studies. In conclusion, the cell assembly-framework suggests a more fine-grained description of the issue of cortical laterality; it is not appropriate to ask whether "modules" supporting higher cortical functions are located either in the left or right hemisphere. Rather, it appears fruitful to ask how the neurons of transcortical cell assemblies are balanced between the hemispheres.

  13. Vertical and interhemispheric links in the stratosphere-mesosphere as revealed by the day-to-day variability of Aura-MLS temperature data

    Directory of Open Access Journals (Sweden)

    X. Xu

    2009-09-01

    Full Text Available The coupling processes in the middle atmosphere have been a subject of intense research activity because of their effects on atmospheric circulation, structure, variability, and the distribution of chemical constituents. In this study, the day-to-day variability of Aura-MLS (Microwave Limb Sounder temperature data are used to reveal the vertical and interhemispheric coupling processes in the stratosphere-mesosphere during four Northern Hemisphere winters (2004/2005–2007/2008. The UKMO (United Kingdom Meteorological Office assimilated data and mesospheric winds from MF (medium frequency radars are also applied to help highlight the coupling processes. In this study, a clear vertical link can be seen between the stratosphere and mesosphere during winter months. The coolings and reversals of northward meridional winds in the polar winter mesosphere are often observed in relation to warming events (Sudden Stratospheric Warming, SSW for short and the associated changes in zonal winds in the polar winter stratosphere. An upper-mesospheric cooling usually precedes the beginning of the warming in the stratosphere by 1–2 days. Inter-hemispheric coupling has been identified initially by a correlation analysis using the year-to-year monthly zonal mean temperature. Then the correlation analyses are performed based upon the daily zonal mean temperature. From the original time sequences, significant positive (negative correlations are generally found between zonal mean temperatures at the Antarctic summer mesopause and in the Arctic winter stratosphere (mesosphere during northern mid-winters, although these correlations are dominated by the low frequency variability (i.e. the seasonal trend. Using the short-term oscillations (less than 15 days, the statistical result, by looking for the largest magnitude of correlation within a range of time-lags (0 to 10 days; positive lags mean that the Antarctic summer mesopause is lagging, indicates that the temporal

  14. Vertical and interhemispheric links in the stratosphere-mesosphere as revealed by the day-to-day variability of Aura-MLS temperature data

    Directory of Open Access Journals (Sweden)

    X. Xu

    2009-09-01

    Full Text Available The coupling processes in the middle atmosphere have been a subject of intense research activity because of their effects on atmospheric circulation, structure, variability, and the distribution of chemical constituents. In this study, the day-to-day variability of Aura-MLS (Microwave Limb Sounder temperature data are used to reveal the vertical and interhemispheric coupling processes in the stratosphere-mesosphere during four Northern Hemisphere winters (2004/2005–2007/2008. The UKMO (United Kingdom Meteorological Office assimilated data and mesospheric winds from MF (medium frequency radars are also applied to help highlight the coupling processes.

    In this study, a clear vertical link can be seen between the stratosphere and mesosphere during winter months. The coolings and reversals of northward meridional winds in the polar winter mesosphere are often observed in relation to warming events (Sudden Stratospheric Warming, SSW for short and the associated changes in zonal winds in the polar winter stratosphere. An upper-mesospheric cooling usually precedes the beginning of the warming in the stratosphere by 1–2 days.

    Inter-hemispheric coupling has been identified initially by a correlation analysis using the year-to-year monthly zonal mean temperature. Then the correlation analyses are performed based upon the daily zonal mean temperature. From the original time sequences, significant positive (negative correlations are generally found between zonal mean temperatures at the Antarctic summer mesopause and in the Arctic winter stratosphere (mesosphere during northern mid-winters, although these correlations are dominated by the low frequency variability (i.e. the seasonal trend. Using the short-term oscillations (less than 15 days, the statistical result, by looking for the largest magnitude of correlation within a range of time-lags (0 to 10 days; positive lags mean that the Antarctic summer mesopause is lagging, indicates

  15. Motor Cortex and Motor Cortical Interhemispheric Communication in Walking After Stroke: The Roles of Transcranial Magnetic Stimulation and Animal Models in Our Current and Future Understanding.

    Science.gov (United States)

    Charalambous, Charalambos C; Bowden, Mark G; Adkins, DeAnna L

    2016-01-01

    Despite the plethora of human neurophysiological research, the bilateral involvement of the leg motor cortical areas and their interhemispheric interaction during both normal and impaired human walking is poorly understood. Using transcranial magnetic stimulation (TMS), we have expanded our understanding of the role upper-extremity motor cortical areas play in normal movements and how stroke alters this role, and probed the efficacy of interventions to improve post-stroke arm function. However, similar investigations of the legs have lagged behind, in part, due to the anatomical difficulty in using TMS to stimulate the leg motor cortical areas. Additionally, leg movements are predominately bilaterally controlled and require interlimb coordination that may involve both hemispheres. The sensitive, but invasive, tools used in animal models of locomotion hold great potential for increasing our understanding of the bihemispheric motor cortical control of walking. In this review, we discuss 3 themes associated with the bihemispheric motor cortical control of walking after stroke: (a) what is known about the role of the bihemispheric motor cortical control in healthy and poststroke leg movements, (b) how the neural remodeling of the contralesional hemisphere can affect walking recovery after a stroke, and (c) what is the effect of behavioral rehabilitation training of walking on the neural remodeling of the motor cortical areas bilaterally. For each theme, we discuss how rodent models can enhance the present knowledge on human walking by testing hypotheses that cannot be investigated in humans, and how these findings can then be back-translated into the neurorehabilitation of poststroke walking. © The Author(s) 2015.

  16. Interhemispheric teleconnections: Late Pliocene change in Mediterranean outflow water linked to changes in Indonesian Through-Flow and Atlantic Meridional Overturning Circulation, a review and update

    Science.gov (United States)

    Sarnthein, Michael; Grunert, Patrick; Khélifi, Nabil; Frank, Martin; Nürnberg, Dirk

    2017-07-01

    The ultimate, possibly geodynamic control and potential impact of changes in circulation activity and salt discharge of Mediterranean outflow waters (MOW) on Atlantic meridional overturning circulation have formed long-standing objectives in paleoceanography. Late Pliocene changes in the distal advection of MOW were reconstructed on orbital timescales for northeast Atlantic DSDP/ODP sites 548 and 982 off Brittany and on Rockall Plateau, supplemented by a proximal record from Site U1389 west off Gibraltar, and compared to Western Mediterranean surface and deep-water records of Alboran Sea Site 978. From 3.43 to 3.3 Ma, MOW temperatures and salinities form a prominent rise by 2-4 °C and 3 psu, induced by a preceding and coeval rise in sea surface and deep-water salinity and increased summer aridity in the Mediterranean Sea. We speculate that these changes triggered an increased MOW flow and were ultimately induced by a persistent 2.5 °C cooling of Indonesian Through-Flow waters. The temperature drop resulted from the northward drift of Australia that crossed a threshold value near 3.6-3.3 Ma and led to a large-scale cooling of the eastern subtropical Indian Ocean and in turn, to a reduction of African monsoon rains. Vice versa, we show that the distinct rise in Mediterranean salt export after 3.4 Ma induced a unique long-term rise in the formation of Upper North Atlantic Deep Water, that followed with a phase lag of 100 ky. In summary, we present evidence for an interhemispheric teleconnection of processes in the Indonesian Gateways, the Mediterranean and Labrador Seas, jointly affecting Pliocene climate.

  17. Interhemispheric teleconnections: Late Pliocene change in Mediterranean outflow water linked to changes in Indonesian Through-Flow and Atlantic Meridional Overturning Circulation, a review and update

    Science.gov (United States)

    Sarnthein, Michael; Grunert, Patrick; Khélifi, Nabil; Frank, Martin; Nürnberg, Dirk

    2018-03-01

    The ultimate, possibly geodynamic control and potential impact of changes in circulation activity and salt discharge of Mediterranean outflow waters (MOW) on Atlantic meridional overturning circulation have formed long-standing objectives in paleoceanography. Late Pliocene changes in the distal advection of MOW were reconstructed on orbital timescales for northeast Atlantic DSDP/ODP sites 548 and 982 off Brittany and on Rockall Plateau, supplemented by a proximal record from Site U1389 west off Gibraltar, and compared to Western Mediterranean surface and deep-water records of Alboran Sea Site 978. From 3.43 to 3.3 Ma, MOW temperatures and salinities form a prominent rise by 2-4 °C and 3 psu, induced by a preceding and coeval rise in sea surface and deep-water salinity and increased summer aridity in the Mediterranean Sea. We speculate that these changes triggered an increased MOW flow and were ultimately induced by a persistent 2.5 °C cooling of Indonesian Through-Flow waters. The temperature drop resulted from the northward drift of Australia that crossed a threshold value near 3.6-3.3 Ma and led to a large-scale cooling of the eastern subtropical Indian Ocean and in turn, to a reduction of African monsoon rains. Vice versa, we show that the distinct rise in Mediterranean salt export after 3.4 Ma induced a unique long-term rise in the formation of Upper North Atlantic Deep Water, that followed with a phase lag of 100 ky. In summary, we present evidence for an interhemispheric teleconnection of processes in the Indonesian Gateways, the Mediterranean and Labrador Seas, jointly affecting Pliocene climate.

  18. The SNAP Strong Lens Survey

    Energy Technology Data Exchange (ETDEWEB)

    Marshall, P.

    2005-01-03

    Basic considerations of lens detection and identification indicate that a wide field survey of the types planned for weak lensing and Type Ia SNe with SNAP are close to optimal for the optical detection of strong lenses. Such a ''piggy-back'' survey might be expected even pessimistically to provide a catalogue of a few thousand new strong lenses, with the numbers dominated by systems of faint blue galaxies lensed by foreground ellipticals. After sketching out our strategy for detecting and measuring these galaxy lenses using the SNAP images, we discuss some of the scientific applications of such a large sample of gravitational lenses: in particular we comment on the partition of information between lens structure, the source population properties and cosmology. Understanding this partitioning is key to assessing strong lens cosmography's value as a cosmological probe.

  19. Strong coupling phase in QED

    International Nuclear Information System (INIS)

    Aoki, Ken-ichi

    1988-01-01

    Existence of a strong coupling phase in QED has been suggested in solutions of the Schwinger-Dyson equation and in Monte Carlo simulation of lattice QED. In this article we recapitulate the previous arguments, and formulate the problem in the modern framework of the renormalization theory, Wilsonian renormalization. This scheme of renormalization gives the best understanding of the basic structure of a field theory especially when it has a multi-phase structure. We resolve some misleading arguments in the previous literature. Then we set up a strategy to attack the strong phase, if any. We describe a trial; a coupled Schwinger-Dyson equation. Possible picture of the strong coupling phase QED is presented. (author)

  20. Strong Decomposition of Random Variables

    DEFF Research Database (Denmark)

    Hoffmann-Jørgensen, Jørgen; Kagan, Abram M.; Pitt, Loren D.

    2007-01-01

    A random variable X is stongly decomposable if X=Y+Z where Y=Φ(X) and Z=X-Φ(X) are independent non-degenerated random variables (called the components). It is shown that at least one of the components is singular, and we derive a necessary and sufficient condition for strong decomposability...

  1. Strong interaction at finite temperature

    Indian Academy of Sciences (India)

    Abstract. We review two methods discussed in the literature to determine the effective parameters of strongly interacting particles as they move through a heat bath. The first one is the general method of chiral perturbation theory, which may be readily applied to this problem. The other is the method of thermal QCD sum rules ...

  2. Strong-strong beam-beam simulation on parallel computer

    Energy Technology Data Exchange (ETDEWEB)

    Qiang, Ji

    2004-08-02

    The beam-beam interaction puts a strong limit on the luminosity of the high energy storage ring colliders. At the interaction points, the electromagnetic fields generated by one beam focus or defocus the opposite beam. This can cause beam blowup and a reduction of luminosity. An accurate simulation of the beam-beam interaction is needed to help optimize the luminosity in high energy colliders.

  3. Strong-strong beam-beam simulation on parallel computer

    International Nuclear Information System (INIS)

    Qiang, Ji

    2004-01-01

    The beam-beam interaction puts a strong limit on the luminosity of the high energy storage ring colliders. At the interaction points, the electromagnetic fields generated by one beam focus or defocus the opposite beam. This can cause beam blowup and a reduction of luminosity. An accurate simulation of the beam-beam interaction is needed to help optimize the luminosity in high energy colliders

  4. Radioactive materials transport; Le transport des matieres radioactives

    Energy Technology Data Exchange (ETDEWEB)

    Talbi, B.

    1996-10-01

    The development of peaceful applications of nuclear energy results in the increase of transport operations of radioactive materials. Therefore strong regulations on transport of radioactive materials turns out to be a necessity in Tunisia. This report presents the different axes of regulations which include the means of transport involved, the radiation protection of the carriers, the technical criteria of security in transport, the emergency measures in case of accidents and penalties in case of infringement. (TEC). 12 refs., 1 fig.

  5. Strongly correlated systems experimental techniques

    CERN Document Server

    Mancini, Ferdinando

    2015-01-01

    The continuous evolution and development of experimental techniques is at the basis of any fundamental achievement in modern physics. Strongly correlated systems (SCS), more than any other, need to be investigated through the greatest variety of experimental techniques in order to unveil and crosscheck the numerous and puzzling anomalous behaviors characterizing them. The study of SCS fostered the improvement of many old experimental techniques, but also the advent of many new ones just invented in order to analyze the complex behaviors of these systems. Many novel materials, with functional properties emerging from macroscopic quantum behaviors at the frontier of modern research in physics, chemistry and materials science, belong to this class of systems. The volume presents a representative collection of the modern experimental techniques specifically tailored for the analysis of strongly correlated systems. Any technique is presented in great detail by its own inventor or by one of the world-wide recognize...

  6. Strongly Correlated Systems Theoretical Methods

    CERN Document Server

    Avella, Adolfo

    2012-01-01

    The volume presents, for the very first time, an exhaustive collection of those modern theoretical methods specifically tailored for the analysis of Strongly Correlated Systems. Many novel materials, with functional properties emerging from macroscopic quantum behaviors at the frontier of modern research in physics, chemistry and materials science, belong to this class of systems. Any technique is presented in great detail by its own inventor or by one of the world-wide recognized main contributors. The exposition has a clear pedagogical cut and fully reports on the most relevant case study where the specific technique showed to be very successful in describing and enlightening the puzzling physics of a particular strongly correlated system. The book is intended for advanced graduate students and post-docs in the field as textbook and/or main reference, but also for other researchers in the field who appreciates consulting a single, but comprehensive, source or wishes to get acquainted, in a as painless as po...

  7. Strongly correlated systems numerical methods

    CERN Document Server

    Mancini, Ferdinando

    2013-01-01

    This volume presents, for the very first time, an exhaustive collection of those modern numerical methods specifically tailored for the analysis of Strongly Correlated Systems. Many novel materials, with functional properties emerging from macroscopic quantum behaviors at the frontier of modern research in physics, chemistry and material science, belong to this class of systems. Any technique is presented in great detail by its own inventor or by one of the world-wide recognized main contributors. The exposition has a clear pedagogical cut and fully reports on the most relevant case study where the specific technique showed to be very successful in describing and enlightening the puzzling physics of a particular strongly correlated system. The book is intended for advanced graduate students and post-docs in the field as textbook and/or main reference, but also for other researchers in the field who appreciate consulting a single, but comprehensive, source or wishes to get acquainted, in a as painless as possi...

  8. Strongly nonlinear oscillators analytical solutions

    CERN Document Server

    Cveticanin, Livija

    2014-01-01

    This book provides the presentation of the motion of pure nonlinear oscillatory systems and various solution procedures which give the approximate solutions of the strong nonlinear oscillator equations. The book presents the original author’s method for the analytical solution procedure of the pure nonlinear oscillator system. After an introduction, the physical explanation of the pure nonlinearity and of the pure nonlinear oscillator is given. The analytical solution for free and forced vibrations of the one-degree-of-freedom strong nonlinear system with constant and time variable parameter is considered. Special attention is given to the one and two mass oscillatory systems with two-degrees-of-freedom. The criteria for the deterministic chaos in ideal and non-ideal pure nonlinear oscillators are derived analytically. The method for suppressing chaos is developed. Important problems are discussed in didactic exercises. The book is self-consistent and suitable as a textbook for students and also for profess...

  9. Flavour Democracy in Strong Unification

    CERN Document Server

    Abel, S A; Abel, Steven; King, Steven

    1998-01-01

    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 $SU(3)_L\\times SU(3)_R$ family symmetry which illustrates our approach.

  10. Wavelength dependence of light diffusion in strongly scattering macroporous gallium phosphide

    NARCIS (Netherlands)

    Peeters, W.H.; Vellekoop, Ivo Micha; Mosk, Allard; Lagendijk, Aart

    2008-01-01

    We present time-resolved measurements of light transport through strongly scattering macroporous gallium phosphide at various vacuum wavelengths between 705 nm and 855 nm. Within this range the transport mean free path is strongly wavelength dependent, whereas the observed energy velocity is shown

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

    DEFF Research Database (Denmark)

    Jepsen, Peter Uhd

    2017-01-01

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

  12. Atoms in strong laser fields

    International Nuclear Information System (INIS)

    L'Huillier, A.

    2002-01-01

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

  13. Strongly Interacting Light Dark Matter

    Directory of Open Access Journals (Sweden)

    Sebastian Bruggisser, Francesco Riva, Alfredo Urbano

    2017-09-01

    Full Text Available In the presence of approximate global symmetries that forbid relevant interactions, strongly coupled light Dark Matter (DM can appear weakly coupled at small energy and generate a sizable relic abundance. Fundamental principles like unitarity restrict these symmetries to a small class, where the leading interactions are captured by effective operators up to dimension-8. Chiral symmetry, spontaneously broken global symmetries and non-linearly realized supersymmetry are examples of this. Their DM candidates (composite fermions, pseudo Nambu-Goldstone Bosons and Goldstini are interesting targets for LHC missing-energy searches.

  14. Strongly interacting light dark matter

    International Nuclear Information System (INIS)

    Bruggisser, Sebastian; Riva, Francesco; Urbano, Alfredo

    2016-07-01

    In the presence of approximate global symmetries that forbid relevant interactions, strongly coupled light Dark Matter (DM) can appear weakly coupled at small-energy and generate a sizable relic abundance. Fundamental principles like unitarity restrict these symmetries to a small class, where the leading interactions are captured by effective operators up to dimension-8. Chiral symmetry, spontaneously broken global symmetries and non-linearly realized supersymmetry are examples of this. Their DM candidates (composite fermions, pseudo-Nambu-Goldstone Bosons and Goldstini) are interesting targets for LHC missing-energy searches.

  15. Rydberg atoms in strong fields

    International Nuclear Information System (INIS)

    Kleppner, D.; Tsimmerman, M.

    1985-01-01

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

  16. Scalar strong interaction hadron theory

    CERN Document Server

    Hoh, Fang Chao

    2015-01-01

    The scalar strong interaction hadron theory, SSI, is a first principles' and nonlocal theory at quantum mechanical level that provides an alternative to low energy QCD and Higgs related part of the standard model. The quark-quark interaction is scalar rather than color-vectorial. A set of equations of motion for mesons and another set for baryons have been constructed. This book provides an account of the present state of a theory supposedly still at its early stage of development. This work will facilitate researchers interested in entering into this field and serve as a basis for possible future development of this theory.

  17. Strong Plate, Weak Slab Dichotomy

    Science.gov (United States)

    Petersen, R. I.; Stegman, D. R.; Tackley, P.

    2015-12-01

    Models of mantle convection on Earth produce styles of convection that are not observed on Earth.Moreover non-Earth-like modes, such as two-sided downwellings, are the de facto mode of convection in such models.To recreate Earth style subduction, i.e. one-sided asymmetric recycling of the lithosphere, proper treatment of the plates and plate interface are required. Previous work has identified several model features that promote subduction. A free surface or pseudo-free surface and a layer of material with a relatively low strength material (weak crust) allow downgoing plates to bend and slide past overriding without creating undue stress at the plate interface. (Crameri, et al. 2012, GRL)A low viscosity mantle wedge, possibly a result of slab dehydration, decouples the plates in the system. (Gerya et al. 2007, Geo)Plates must be composed of material which, in the case of the overriding plate, are is strong enough to resist bending stresses imposed by the subducting plate and yet, as in the case of the subducting plate, be weak enough to bend and subduct when pulled by the already subducted slab. (Petersen et al. 2015, PEPI) Though strong surface plates are required for subduction such plates may present a problem when they encounter the lower mantle.As the subducting slab approaches the higher viscosity, lower mantle stresses are imposed on the tip.Strong slabs transmit this stress to the surface.There the stress field at the plate interface is modified and potentially modifies the style of convection. In addition to modifying the stress at the plate interface, the strength of the slab affects the morphology of the slab at the base of the upper mantle. (Stegman, et al 2010, Tectonophysics)Slabs that maintain a sufficient portion of their strength after being bent require high stresses to unbend or otherwise change their shape.On the other hand slabs that are weakened though the bending process are more amenable to changes in morphology. We present the results of

  18. Radiation Transport

    Energy Technology Data Exchange (ETDEWEB)

    Urbatsch, Todd James [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-06-15

    We present an overview of radiation transport, covering terminology, blackbody raditation, opacities, Boltzmann transport theory, approximations to the transport equation. Next we introduce several transport methods. We present a section on Caseology, observing transport boundary layers. We briefly broach topics of software development, including verification and validation, and we close with a section on high energy-density experiments that highlight and support radiation transport.

  19. Physics of Strongly Coupled Plasma

    Energy Technology Data Exchange (ETDEWEB)

    Kraeft, Wolf-Dietrich [Universitat Rostock (Germany)

    2007-07-15

    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 performed 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

  20. Strongly coupled dust coulomb clusters

    International Nuclear Information System (INIS)

    Juan Wentau; Lai Yingju; Chen Mingheng; I Lin

    1999-01-01

    The structures and motions of quasi-2-dimensional strongly coupled dust Coulomb clusters with particle number N from few to hundreds in a cylindrical rf plasma trap are studied and compared with the results from the molecular dynamic simulation using more ideal models. Shell structures with periodic packing in different shells and intershell rotational motion dominated excitations are observed at small N. As N increases, the boundary has less effect, the system recovers to the triangular lattice with isotropic vortex type cooperative excitations similar to an infinite N system except the outer shell region. The above generic behaviors are mainly determined by the system symmetry and agree with the simulation results. The detailed interaction form causes minor effect such as the fine structure of packing

  1. Probability densities in strong turbulence

    Science.gov (United States)

    Yakhot, Victor

    2006-03-01

    In this work we, using Mellin’s transform combined with the Gaussian large-scale boundary condition, calculate probability densities (PDFs) of velocity increments P(δu,r), velocity derivatives P(u,r) and the PDF of the fluctuating dissipation scales Q(η,Re), where Re is the large-scale Reynolds number. The resulting expressions strongly deviate from the Log-normal PDF P(δu,r) often quoted in the literature. It is shown that the probability density of the small-scale velocity fluctuations includes information about the large (integral) scale dynamics which is responsible for the deviation of P(δu,r) from P(δu,r). An expression for the function D(h) of the multifractal theory, free from spurious logarithms recently discussed in [U. Frisch, M. Martins Afonso, A. Mazzino, V. Yakhot, J. Fluid Mech. 542 (2005) 97] is also obtained.

  2. Chamber transport

    International Nuclear Information System (INIS)

    Olson, Craig L.

    2001-01-01

    Heavy ion beam transport through the containment chamber plays a crucial role in all heavy ion fusion (HIF) scenarios. Here, several parameters are used to characterize the operating space for HIF beams; transport modes are assessed in relation to evolving target/accelerator requirements; results of recent relevant experiments and simulations of HIF transport are summarized; and relevant instabilities are reviewed. All transport options still exist, including (1) vacuum ballistic transport, (2) neutralized ballistic transport, and (3) channel-like transport. Presently, the European HIF program favors vacuum ballistic transport, while the US HIF program favors neutralized ballistic transport with channel-like transport as an alternate approach. Further transport research is needed to clearly guide selection of the most attractive, integrated HIF system

  3. Noise Spectroscopy in Strongly Correlated Oxides

    Science.gov (United States)

    Alsaqqa, Ali M.

    Strongly correlated materials are an interesting class of materials, thanks to the novel electronic and magnetic phenomena they exhibit as a result of the interplay of various degrees of freedom. This gives rise to an array of potential applications, from Mott-FET to magnetic storage. Many experimental probes have been used to study phase transitions in strongly correlated oxides. Among these, resistance noise spectroscopy, together with conventional transport measurements, provides a unique viewpoint to understand the microscopic dynamics near the phase transitions in these oxides. In this thesis, utilizing noise spectroscopy and transport measurements, four different strongly correlated materials were studied: (1) neodymium nickel oxide (NdNiO 3) ultrathin films, (2) vanadium dioxide (VO2) microribbons, (3) copper vanadium bronze (CuxV2O 5) microribbons and (4) niobium triselenide (NbSe3) microribbons. Ultra thin films of rare-earth nickelates exhibit several temperature-driven phase transitions. In this thesis, we studied the metal-insulator and Neel transitions in a series of NdNiO3 films with different lattice mismatches. Upon colling down, the metal-insulator phase transition is accompanied by a structural (orthorohombic to monoclinic) and magnetic (paramagnetic to antiferromagnetic) transitions as well, making the problem more interesting and complex at the same time. The noise is of the 1/f type and is Gaussian in the high temperature phase, however deviations are seen in the low temperature phases. Below the metal-insulator transition, noise magnitude increases by orders of magnitude: a sign of inhomogeneous electrical conduction as result of phase separation. This is further assured by the non-Gaussian noise signature. At very low temperatures (T thesis, we tried to answer this question by utilizing three different tuning parameters: temperature, voltage bias and strain. Our results point to an unusual noise behavior in the high-temperature metallic phase

  4. Strong Ideal Convergence in Probabilistic Metric Spaces

    Indian Academy of Sciences (India)

    In the present paper we introduce the concepts of strongly ideal convergent sequence and strong ideal Cauchy sequence in a probabilistic metric (PM) space endowed with the strong topology, and establish some basic facts. Next, we define the strong ideal limit points and the strong ideal cluster points of a sequence in this ...

  5. Strong ideal convergence in probabilistic metric spaces

    Indian Academy of Sciences (India)

    In the present paper we introduce the concepts of strongly ideal convergent sequence and strong ideal Cauchy sequence in a probabilistic metric (PM) space endowed with the strong topology, and establish some basic facts. Next, we define the strong ideal limit points and the strong ideal cluster points of a sequence in this ...

  6. Remnants of strong tidal interactions

    International Nuclear Information System (INIS)

    Mcglynn, T.A.

    1990-01-01

    This paper examines the properties of stellar systems that have recently undergone a strong tidal shock, i.e., a shock which removes a significant fraction of the particles in the system, and where the shocked system has a much smaller mass than the producer of the tidal field. N-body calculations of King models shocked in a variety of ways are performed, and the consequences of the shocks are investigated. The results confirm the prediction of Jaffe for shocked systems. Several models are also run where the tidal forces on the system are constant, simulating a circular orbit around a primary, and the development of tidal radii under these static conditions appears to be a mild process which does not dramatically affect material that is not stripped. The tidal radii are about twice as large as classical formulas would predict. Remnant density profiles are compared with a sample of elliptical galaxies, and the implications of the results for the development of stellar populations and galaxies are considered. 38 refs

  7. John Strong - 1941-2006

    CERN Document Server

    2006-01-01

    Our friend and colleague John Strong was cruelly taken from us by a brain tumour on 31 July, a few days before his 65th birthday. John started his career and obtained his PhD in a group from Westfield College, initially working on experiments at Rutherford Appleton Laboratory (RAL). From the early 1970s onwards, however, his research was focused on experiments in CERN, with several particularly notable contributions. The Omega spectrometer adopted a system John had originally developed for experiments at RAL using vidicon cameras (a type of television camera) to record the sparks in the spark chambers. This highly automated system allowed Omega to be used in a similar way to bubble chambers. He contributed to the success of NA1 and NA7, where he became heavily involved in the electronic trigger systems. In these experiments the Westfield group joined forces with Italian colleagues to measure the form factors of the pion and the kaon, and the lifetime of some of the newly discovered charm particles. Such h...

  8. Strong seismic ground motion propagation

    International Nuclear Information System (INIS)

    Seale, S.; Archuleta, R.; Pecker, A.; Bouchon, M.; Mohammadioun, G.; Murphy, A.; Mohammadioun, B.

    1988-10-01

    At the McGee Creek, California, site, 3-component strong-motion accelerometers are located at depths of 166 m, 35 m and 0 m. The surface material is glacial moraine, to a depth of 30.5 m, overlying homfels. Accelerations were recorded from two California earthquakes: Round Valley, M L 5.8, November 23, 1984, 18:08 UTC and Chalfant Valley, M L 6.4, July 21, 1986, 14:42 UTC. By separating out the SH components of acceleration, we were able to determine the orientations of the downhole instruments. By separating out the SV component of acceleration, we were able to determine the approximate angle of incidence of the signal at 166 m. A constant phase velocity Haskell-Thomson model was applied to generate synthetic SH seismograms at the surface using the accelerations recorded at 166 m. In the frequency band 0.0 - 10.0 Hz, we compared the filtered synthetic records to the filtered surface data. The onset of the SH pulse is clearly seen, as are the reflections from the interface at 30.5 m. The synthetic record closely matches the data in amplitude and phase. The fit between the synthetic accelerogram and the data shows that the seismic amplification at the surface is a result of the contrast of the impedances (shear stiffnesses) of the near surface materials

  9. Strong paramagnon scattering in single atom Pd contacts

    DEFF Research Database (Denmark)

    Schendel, V.; Barreteau, Cyrille; Brandbyge, Mads

    2017-01-01

    Among all transition metals, palladium (Pd) has the highest density of states at the Fermi energy at low temperatures yet does not fulfill the Stoner criterion for ferromagnetism. However, close proximity to magnetism renders it a nearly ferromagnetic metal, which hosts paramagnons, strongly damp...... adatoms locally induce magnetic order, and transport through single cobalt atoms remains unaffected by paramagnon scattering, consistent with theory....... spin fluctuations. Here we compare the total and the differential conductance of monoatomic contacts consisting of single Pd and cobalt (Co) atoms between Pd electrodes. Transport measurements reveal a conductance for Co of 1G(0), while for Pd we obtain 2G(0). The differential conductance of monoatomic...

  10. Sustainable Transportation

    DEFF Research Database (Denmark)

    Hall, Ralph P.; Gudmundsson, Henrik; Marsden, Greg

    2014-01-01

    that relate to the construction and maintenance of transportation infrastructure and the operation or use of the different transportation modes. The concept of sustainable transportation emerged in response to these concerns as part of the broader notion of sustainable development. Given the transportation...... sector’s significant contribution to global challenges such as climate change, it is often said that sustainable development cannot be achieved without sustainable transportation....

  11. Strongly interacting photons and atoms

    International Nuclear Information System (INIS)

    Alge, W.

    1999-05-01

    This thesis contains the main results of the research topics I have pursued during the my PhD studies at the University of Innsbruck and partly in collaboration with the Institut d' Optique in Orsay, France. It is divided into three parts. The first and largest part discusses the possibility of using strong standing waves as a tool to cool and trap neutral atoms in optical cavities. This is very important in the field of nonlinear optics where several successful experiments with cold atoms in cavities have been performed recently. A discussion of the optical parametric oscillator in a regime where the nonlinearity dominates the evolution is the topic of the second part. We investigated mainly the statistical properties of the cavity output of the three interactive cavity modes. Very recently a system has been proposed which promises fantastic properties. It should exhibit a giant Kerr nonlinearity with negligible absorption thus leading to a photonic turnstile device based on cold atoms in cavity. We have shown that this model suffers from overly simplistic assumptions and developed several more comprehensive approaches to study the behavior of this system. Apart from the division into three parts of different contents the thesis is divided into publications, supplements and invisible stuff. The intention of the supplements is to reach researchers which work in related areas and provide them with more detailed information about the concepts and the numerical tools we used. It is written especially for diploma and PhD students to give them a chance to use the third part of our work which is actually the largest one. They consist of a large number of computer programs we wrote to investigate the behavior of the systems in parameter regions where no hope exists to solve the equations analytically. (author)

  12. Topics in strong Langmuir turbulence

    International Nuclear Information System (INIS)

    Skoric, M.M.

    1981-01-01

    This thesis discusses certain aspects of the turbulence of a fully ionised non-isothermal plasma dominated by the Langmuir mode. Some of the basic properties of strongly turbulent plasmas are reviewed. In particular, interest is focused on the state of Langmuir turbulence, that is the turbulence of a simple externally unmagnetized plasma. The problem of the existence and dynamics of Langmuir collapse is discussed, often met as a non-linear stage of the modulational instability in the framework of the Zakharov equations (i.e. simple time-averaged dynamical equations). Possible macroscopic consequences of such dynamical turbulent models are investigated. In order to study highly non-linear collapse dynamics in its advanced stage, a set of generalized Zakharov equations are derived. Going beyond the original approximation, the author includes the effects of higher electron non-linearities and a breakdown of slow-timescale quasi-neutrality. He investigates how these corrections may influence the collapse stabilisation. Recently, it has been realised that the modulational instability in a Langmuir plasma will be accompanied by the collisionless-generation of a slow-timescale magnetic field. Accordingly, a novel physical situation has emerged which is investigated in detail. The stability of monochromatic Langmuir waves in a self-magnetized Langmuir plasma, is discussed, and the existence of a novel magneto-modulational instability shown. The wave collapse dynamics is investigated and a physical interpretation of the basic results is given. A problem of the transient analysis of an interaction of time-dependent electromagnetic pulses with linear cold plasma media is investigated. (Auth.)

  13. Promoting Strong Written Communication Skills

    Science.gov (United States)

    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

  14. Intense Shock Waves and Strongly Coupled Plasmas

    Science.gov (United States)

    Fortov, Vladimir

    2005-07-01

    The report presents the recent results of experimental investigations of equations of state, compositions, thermodynamical and transport properties, electrical conductivity and opacity of strongly coupled plasmas generated by intense shock and rarefaction waves. The experimental methods for generation of high energy densities in matter, drivers for shock waves and fast diagnostic tools are discussed. Application of intense shock waves to solid and porous targets generates nonideal plasmas in megabar-gigabar pressure range. Compression of plasma by a series of reverberating shock waves allows us to decrease irreversible heating effects. To increase the irreversibility effects and to generate high temperature plasma states the experiments on shock compression of porous samples (fine metal powder, aerogels) were performed. The adiabatic expansion of matter initially compressed by intense shocks up to megabars allows investigating the intermediate region between the solid and vapor phase of nonideal plasmas, including the metal-insulator transition phase and the high temperature saturation curve with critical points of metals. The shock-wave-induced non-equilibrium phenomena at fast melting, spallation and adiabatic condensation are analyzed in the framework of the interspinodal decomposition model. The spall strength of single and polycrystal metals at extremely fast deformation produced by fast shock waves is discussed. The ``pressure ionization'' phenomena in hydrogen, helium, argon, xenon, krypton, neon, iodine, silica, sulfur, fullerenes, and some metals are analyzed on the base of multiple shock compression experiments. For some simple metals (Li, Na, Ca) the effect of ``dielectrization'' as a result of multiple shock compression are discussed.

  15. Thermodynamics of strong-interaction matter from Lattice QCD

    OpenAIRE

    Ding, Heng-Tong; Karsch, Frithjof; Mukherjee, Swagato

    2015-01-01

    We review results from lattice QCD calculations on the thermodynamics of strong-interaction matter with emphasis on input these calculations can provide to the exploration of the phase diagram and properties of hot and dense matter created in heavy ion experiments. This review is organized as follows: 1) Introduction, 2) QCD thermodynamics on the lattice, 3) QCD phase diagram at high temperature, 4) Bulk thermodynamics, 5) Fluctuations of conserved charges, 6) Transport properties, 7) Open he...

  16. Some Applications of Holography to Study Strongly Correlated Systems

    Directory of Open Access Journals (Sweden)

    Bhatnagar Neha

    2018-01-01

    Full Text Available In this work, we study the transport coefficients of strongly coupled condensed matter systems using gauge/gravity duality (holography. We consider examples from the real world and evaluate the conductivities from their gravity duals. Adopting the bottom-up approach of holography, we obtain the frequency response of the conductivity for (1+1-dimensional systems. We also evaluate the DC conductivities for non-relativistic condensed matter systems with hyperscaling violating geometry.

  17. Os efeitos da estimulação elétrica funcional na assimetria cortical inter-hemisférica The effects of functional electrical stimulation on cortical interhemispheric asymmetry

    Directory of Open Access Journals (Sweden)

    Letícia Ecard

    2007-09-01

    Full Text Available O objetivo do presente estudo foi avaliar os efeitos da estimulação elétrica funcional na assimetria cortical inter-hemisférica. Para tal, simultaneamente ao registro da atividade eletroencefalográfica, realizou-se eletroestimulação no antebraço direito para estimulação da extensão do indicador. A amostra consistiu de 45 sujeitos randomizados em 3 grupos de 15 sujeitos cada: grupo controle (submetido a 24 blocos de estimulação com intensidade de corrente zero, grupo 1 (24 blocos e grupo 2 (36 blocos. A assimetria entre os pares de eletrodos F3-F4, C3-C4 e P3-P4 foi analisada ao longo dos grupos através de uma Anova. Os resultados apontaram para uma interação grupo x eletrodo e uma tendência de diminuição da assimetria inter-hemisférica após a eletroestimulação.The aim of the present study was to assess the effects of functional electrical stimulation (FES on cortical interhemispheric asymmetry. Electrostimulation was performed on the right forearm to stimulate the extension of the index finger. EEG activity was recorded simultaneously. The sample included 45 subjects randomly divided into 3 groups of 15 subjects each: control group (submitted to 24 blocks of stimulation at a null intensity current, group 1 (24 blocks and group 2 (36 blocks. Interhemispheric asymmetry between F3-F4, C3-C4 and P3-P4 was analyzed through an Anova. Results pointed out to a group x electrode interaction and a general tendency of asymmetry decrease after stimulation.

  18. ABC transporters of the wheat pathogen Mycosphaerella graminicola

    NARCIS (Netherlands)

    Zwiers, L.H.

    2002-01-01

    <strong>

    Astrong> TP- <strong>b> inding <strong>c> assette (ABC) transporters belong to one of the largest protein families known. They play a role in numerous vital processes in the cell and are characterised by their

  19. Neurotransmitter transporters

    DEFF Research Database (Denmark)

    Gether, Ulrik; Andersen, Peter H; Larsson, Orla M

    2006-01-01

    The concentration of neurotransmitters in the extracellular space is tightly controlled by distinct classes of membrane transport proteins. This review focuses on the molecular function of two major classes of neurotransmitter transporter that are present in the cell membrane of neurons and....../or glial cells: the solute carrier (SLC)1 transporter family, which includes the transporters that mediate the Na(+)-dependent uptake of glutamate, and the SLC6 transporter family, which includes the transporters that mediate the Na(+)-dependent uptake of dopamine, 5-HT, norepinephrine, glycine and GABA....... Recent research has provided substantial insight into the structure and function of these transporters. In particular, the recent crystallizations of bacterial homologs are of the utmost importance, enabling the first reliable structural models of the mammalian neurotransmitter transporters...

  20. Energy policy in transport and transport policy

    International Nuclear Information System (INIS)

    Van Dender, Kurt

    2009-01-01

    Explanations for, and indirect evidence of, imperfections in the market for private passenger vehicle fuel economy suggest there is a reasonable case for combining fuel economy standards and fuel or carbon taxes to contribute to an energy policy that aims to reduce greenhouse gas emissions and improve energy security. Estimates of key elasticities, including the rebound effect, indicate that the positive and negative side-effects of fuel economy measures on transport activities and external costs are limited. However, an energy policy for transport does not replace a transport policy that aims to manage the main transport externalities including congestion and local pollution. Conventional marginal cost estimates and standard cost-benefit reasoning suggest that policies that address congestion and local pollution likely bring benefits at least as large as those from fuel economy measures. But the large uncertainty on the possible effects of greenhouse gas emissions constitutes a strong challenge for standard cost-benefit reasoning. Emerging results from methods to cope with this uncertainty suggest that policies to stimulate the widespread adoption of low-carbon technologies in transport are justified.

  1. Radial Distribution Functions of Strongly Coupled Two-Temperature Plasmas

    Science.gov (United States)

    Shaffer, Nathaniel R.; Tiwari, Sanat Kumar; Baalrud, Scott D.

    2017-10-01

    We present tests of three theoretical models for the radial distribution functions (RDFs) in two-temperature strongly coupled plasmas. RDFs are useful in extending plasma thermodynamics and kinetic theory to strong coupling, but they are usually known only for thermal equilibrium or for approximate one-component model plasmas. Accurate two-component modeling is necessary to understand the impact of strong coupling on inter-species transport, e.g., ambipolar diffusion and electron-ion temperature relaxation. We demonstrate that the Seuferling-Vogel-Toeppfer (SVT) extension of the hypernetted chain equations not only gives accurate RDFs (as compared with classical molecular dynamics simulations), but also has a simple connection with the Yukawa OCP model. This connection gives a practical means to recover the structure of the electron background from knowledge of the ion-ion RDF alone. Using the model RDFs in Effective Potential Theory, we report the first predictions of inter-species transport coefficients of strongly coupled plasmas far from equilibrium. This work is supported by NSF Grant No. PHY-1453736, AFSOR Award No. FA9550-16-1-0221, and used XSEDE computational resources.

  2. TRANSPORT OF COUNTERFEIT GOODS

    Directory of Open Access Journals (Sweden)

    Dagmar Babčanová

    2014-09-01

    Full Text Available The paper is focused on a current problem of transport of counterfeit goods in the European Union. Counterfeiting has a strong influence on the distribution organizations worldwide because most of counterfeit goods threaten the health and safety of consumers. Counterfeiting is a serious problem in the world economy today. The purpose of this paper is to point out the danger of counterfeiting in connection with the transport of Intellectual Property (IP rights - infringing goods. Background of the paper’s content is based on secondary data research of publicly available sources - international statistics and world reports.

  3. Atoms and clusters in strong laser fields

    NARCIS (Netherlands)

    Marchenko, T.

    2008-01-01

    This thesis describes experimental and theoretical studies on the interaction of strong infrared laser fields with atoms and atomic clusters. Part I provides an overview of the main strong-field phenomena in atoms, molecules and clusters and describes the state-of-the-art in strong-field science.

  4. Strong Bisimilarity of Simple Process Algebras

    DEFF Research Database (Denmark)

    Srba, Jirí

    2003-01-01

    We study bisimilarity and regularity problems of simple process algebras. In particular, we show PSPACE-hardness of the following problems: (i) strong bisimilarity of Basic Parallel Processes (BPP), (ii) strong bisimilarity of Basic Process Algebra (BPA), (iii) strong regularity of BPP, and (iv) ...

  5. 78 FR 15710 - Strong Sensitizer Guidance

    Science.gov (United States)

    2013-03-12

    ... 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 have... document is intended to clarify the ``strong sensitizer'' definition, assist manufacturers in understanding...

  6. What can Transport Deliver?

    DEFF Research Database (Denmark)

    Kobayashi, Shigeki; Fulton, Lewis; Figueroa, Maria J.

    in the evolution of penetration rates for new car and fuel technologies globally. The current level of penetration for hybrids, electric vehicles and biofuels is 2-3% globally, which is far below of the level of 30% or higher required by 2°C scenario in the 2050 time frame. The results of this study suggest...... there is a mismatch between current penetration rates and those needed for global transport to reach identified targets as part of achieving broader climate stabilization targets. Of paramount significance is the strong improvement rates in vehicle efficiency and countries should redouble their efforts to set strong...

  7. Global source attribution of tropospheric ozone: Long-range transport from various source regions

    Science.gov (United States)

    Sudo, K.; Akimoto, H.

    2007-06-01

    We examine contributions from various source regions to global distributions and budgets of tropospheric ozone (O3) in the context of intercontinental transport, using tagged tracer simulation with a global chemical transport model. For tagging O3, we consider regional separation of the model domain on the basis of the distributions of O3 chemical production. We define 14 polluted source regions (14 tracers) in the boundary layer (North America, Europe, China, etc.) and 8 regions (8 tracers) in the free troposphere; O3 production in the remaining (remote) tropospheric region and O3 transport from the stratosphere are also tagged as separate tracers. O3 transport from the polluted source regions like North America, Europe, and Asia generally accounts for more than 40% of ozone abundances even in remote locations. O3 exports from boundary layer in China and Asian free troposphere are discerned through much of the Northern Hemisphere, suggesting significant and extensive impacts of eastern Asian pollution. In particular, O3 from Asian free troposphere plays the most important roles in distribution and seasonal variation of O3 in the middle-upper troposphere almost globally. In June-September, the model calculates a large O3 contribution (5-10 ppbv) from Asian free troposphere in the upper troposphere over the South Pacific associated with long-range interhemispheric transport from Asia to the southern midlatitudes (via the western Indian Ocean, Africa, and Atlantic) in the upper troposphere. O3 transported from biomass burning regions such as South America, Africa, and Australia widely distributes in the Southern Hemisphere. Our simulation demonstrates that there is a significant interhemispheric O3 transport from South America to the northern midlatitudes in the upper troposphere which reaches Japan, North Pacific, and the United States in conjunction with O3 export from North Africa. Our tagged O3 simulation estimates that the annual mean global tropospheric O3

  8. Experimental constraints on transport

    International Nuclear Information System (INIS)

    Luce, T.C.; Petty, K.H.; Burrell, K.H.; Forest, C.B.; Gohil, P.; Groebner, R.J.; De Haas, J.C.M.; James, R.A.; Makowski, M.A.

    1994-12-01

    Characterization of the cross-field energy transport in magnetic confinement experiments in a manner applicable to the accurate assessment of future machine performance continues to be a challenging goal. Experimental results from the DIII-D tokamak in the areas of dimensionless scaling and non-diffusive transport represent progress toward this goal. Dimensionless scaling shows how beneficial the increase in machine size and magnetic field is for future devices. The experiments on DIII-D are the first to determine separately the electron and ion scaling with normalized gyroradius ρ * ; the electrons scale as expected from gyro-Bohm class theories, while the ions scale consistent with the Goldston empirical scaling. This result predicts an increase in transport relative to Bohm diffusion as ρ * decreases in future devices. The existence of distinct ρ * scalings for ions and electrons cautions against a physical interpretation of one-fluid or global analysis. The second class of experiments reported here are the first to demonstrate the existence of non-diffusive energy transport. Electron cyclotron heating was applied at the half radius; the electron temperature profile remains substantially peaked. Power balance analysis indicates that heat must flow in the direction of increasing temperature, which is inconsistent with purely diffusive transport. The dynamics of electron temperature perturbations indicate the presence in the heat flux of a term dependent on temperature rather than its gradient. These two observations strongly constrain the types of models which can be applied to cross-field heat transport

  9. Sediment Transport

    DEFF Research Database (Denmark)

    Liu, Zhou

    Flow and sediment transport are important in relation to several engineering topics, e.g. erosion around structures, backfilling of dredged channels and nearshore morphological change. The purpose of the present book is to describe both the basic hydrodynamics and the basic sediment transport...... mechanics. Chapter 1 deals with fundamentals in fluid mechanics with emphasis on bed shear stress by currents, while chapter 3 discusses wave boundary layer theory. They are both written with a view to sediment transport. Sediment transport in rivers, cross-shore and longshore are dealt with in chapters 2...

  10. Ocean transportation

    National Research Council Canada - National Science Library

    Frankel, Ernst G; Marcus, Henry S

    1973-01-01

    .... This analysis starts with a review of ocean transportation demand and supply including projections of ship capacity demand and world shipbuilding capacity under various economic and political assumptions...

  11. Application of strong phosphoric acid to radiochemistry

    International Nuclear Information System (INIS)

    Terada, Kikuo

    1977-01-01

    Not only inorganic and organic compounds but also natural substrances, such as accumulations in soil, are completely decomposed and distilled by heating with strong phosphoric acid for 30 to 50 minutes. As applications of strong phosphoric acid to radiochemistry, determination of uranium and boron by use of solubilization effect of this substance, titration of uranyl ion by use of sulfuric iron (II) contained in this substance, application to tracer experiment, and determination of radioactive ruthenium in environmental samples are reviewed. Strong phosphoric acid is also applied to activation analysis, for example, determination of N in pyrographite with iodate potassium-strong phosphoric acid method, separation of Os and Ru with sulfuric cerium (IV) - strong phosphoric acid method or potassium dechromate-strong phosphoric acid method, analysis of Se, As and Sb rocks and accumulations with ammonium bromide, sodium chloride and sodium bromide-strong phosphoric acid method. (Kanao, N.)

  12. Improvement of discontinuity factor for strong absorber region

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Jiong, E-mail: guojiong12@mail.tsinghua.edu.cn; Li, Fu, E-mail: lifu@mail.tsinghua.edu.cn; Zhang, Han; Zhou, Xiafeng; Fan, Kai; Wang, Lidong; Lu, Jianan

    2016-09-15

    At Institute of Nuclear and New Energy Technology (INET) the discontinuity factor corrected diffusion method with the homogenization technology was developed and applied in the control rod worth calculation of the pebble bed high temperature gas cooled reactor. But the result with the normal procedure is not accurate enough for a strong absorber. The numerical analysis shows that the strong absorber still has great influence on the flux distribution in the nearby graphite region, so that the flux distribution obtained by the normal diffusion method does not agree with the transport result. Thus, two improvements were proposed in this paper. First, instead of the neutron flux in the middle of the fine mesh, the surface flux of the absorber region was calculated through the net current in the boundary of the region; and then, while the discontinuity factor of the homogenized absorber region should be calculated, the discontinuity factor of the neighboring graphite region on the other side of the interface should also be calculated to eliminate the influence of the strong absorber. The numerical results demonstrate that, based on the improved method, the accuracy of heterogeneous transport calculation can be achieved by a diffusion calculation.

  13. Homogenization technique for strongly heterogeneous zones in research reactors

    International Nuclear Information System (INIS)

    Lee, J.T.; Lee, B.H.; Cho, N.Z.; Oh, S.K.

    1991-01-01

    This paper reports on an iterative homogenization method using transport theory in a one-dimensional cylindrical cell model developed to improve the homogenized cross sections fro strongly heterogeneous zones in research reactors. The flux-weighting homogenized cross sections are modified by a correction factor, the cell flux ratio under an albedo boundary condition. The albedo at the cell boundary is iteratively determined to reflect the geometry effects of the material properties of the adjacent cells. This method has been tested with a simplified core model of the Korea Multipurpose Research Reactor. The results demonstrate that the reaction rates of an off-center control shroud cell, the multiplication factor, and the power distribution of the reactor core are close to those of the fine-mesh heterogeneous transport model

  14. Strongly correlating liquids and their isomorphs

    OpenAIRE

    Pedersen, Ulf R.; Gnan, Nicoletta; Bailey, Nicholas P.; Schröder, Thomas B.; Dyre, Jeppe C.

    2010-01-01

    This paper summarizes the properties of strongly correlating liquids, i.e., liquids with strong correlations between virial and potential energy equilibrium fluctuations at constant volume. We proceed to focus on the experimental predictions for strongly correlating glass-forming liquids. These predictions include i) density scaling, ii) isochronal superposition, iii) that there is a single function from which all frequency-dependent viscoelastic response functions may be calculated, iv) that...

  15. Atom collisions in a strong electromagnetic field

    International Nuclear Information System (INIS)

    Smirnov, V.S.; Chaplik, A.V.

    1976-01-01

    It is shown that the long-range part of interatomic interaction is considerably altered in a strong electromagnetic field. Instead of the van der Waals law the potential asymptote can best be described by a dipole-dipole R -3 law. Impact broadening and the line shift in a strong nonresonant field are calculated. The possibility of bound states of two atoms being formed in a strong light field is discussed

  16. Characteristics of intercontinental transport of tropospheric ozone from Africa to Asia

    Science.gov (United States)

    Han, Han; Liu, Jane; Yuan, Huiling; Zhuang, Bingliang; Zhu, Ye; Wu, Yue; Yan, Yuhan; Ding, Aijun

    2018-03-01

    In this study, we characterize the transport of ozone from Africa to Asia through the analysis of the simulations of a global chemical transport model, GEOS-Chem, from 1987 to 2006. The receptor region Asia is defined within 5-60° N and 60-145° E, while the source region Africa is within 35° S-15° N and 20° W-55° E and within 15-35° N and 20° W-30° E. The ozone generated in the African troposphere from both natural and anthropogenic sources is tracked through tagged ozone simulation. Combining this with analysis of trajectory simulations using the Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model, we find that the upper branch of the Hadley cell connects with the subtropical westerlies in the Northern Hemisphere (NH) to form a primary transport pathway from Africa to Asia in the middle and upper troposphere throughout the year. The Somali jet that runs from eastern Africa near the equator to the Indian subcontinent in the lower troposphere is the second pathway that appears only in NH summer. The influence of African ozone mainly appears over Asia south of 40° N. The influence shows strong seasonality, varying with latitude, longitude, and altitude. In the Asian upper troposphere, imported African ozone is largest from March to May around 30° N (12-16 ppbv) and lowest during July-October around 10° N ( ˜ 2 ppbv). In the Asian middle and lower troposphere, imported African ozone peaks in NH winter between 20 and 25° N. Over 5-40° N, the mean fractional contribution of imported African ozone to the overall ozone concentrations in Asia is largest during NH winter in the middle troposphere ( ˜ 18 %) and lowest in NH summer throughout the tropospheric column ( ˜ 6 %). This seasonality mainly results from the collective effects of the ozone precursor emissions in Africa and meteorology and chemistry in Africa, in Asia and along the transport pathways. The seasonal swing of the Hadley circulation and subtropical westerlies along the

  17. Hydrodynamics of strongly coupled gauge theories from gravity

    International Nuclear Information System (INIS)

    Benincasa, P.

    2007-01-01

    In this talk we review some recent developments in the analysis of gauge theories from a holographic perspective. We focus on the transport properties of strongly coupled gauge theories. In particular, we discuss the results for two specific non-conformal models: the N=2* supersymmetric SU(N c ) Yang-Mills theory and the Sakai-Sugimoto model. Finally, we discuss the hydrodynamic picture for the N=4SU(N c ) SYM theory when the leading correction in the inverse 't Hooft coupling is taken into account

  18. Animal Transports

    Directory of Open Access Journals (Sweden)

    Diana Ludrovcová

    2016-08-01

    Full Text Available Purpose and Originality: The research is aimed to the animal transports issue, from two points of view – first is the animal cruelty and second is the policy and economic consideration. The goal is to acquaint the readers with the transports risks and its cruelty and evaluation of the economic, political aspects for he involved countries. The study is oriented on more points of view, what is rare in works with a similar theme. Method: This paper examines many issues and examinations from different authors and subsequently summarized the findings with authors own knowledge to one expanded unit. Results: Results proves, that livestock transports have negative impact on animal´s health, environment. Number of transported animals is rising every year. Society: Research familiarize the society with the animal transports, cruelty against animals during them, and influence of transports on some countries, their economy, policy. People get better informed and can form their own opinion on this topic. They may start acting, undertaking some steps to improve the present situation, what could help a lot to animals and environment. Limitations / further research: Future research could show progress and improvement of transports, quality of food supply and economics.

  19. Panel 4 - applications to transportation

    Energy Technology Data Exchange (ETDEWEB)

    Nichols, F. [Argonne National Lab., IL (United States); Au, J. [Sundstrand Aerospace, Rockford, IL (United States); Bhattacharya, R. [Universal Energy Systems, Inc., Dayton, OH (United States); Bhushan, B. [Ohio State Univ., Columbus (United States); Blunier, D. [Caterpillar, Inc., Peoria, IL (United States); Boardman, B. [Deere & Co., Moline, IL (United States); Brombolich, L. [Compu-Tec Engineering, Chesterfield, MO (United States); Davidson, J. [Vanderbilt Univ., Nashville, TN (United States); Graham, M. [Northwestern Univ., Evanston, IL (United States); Hakim, N. [Detroit Diesel Corp., MI (United States); Harris, K. [Dubbeldee Harris Diamond Corp., Mt. Arlington, NJ (United States); Hay, R. [Norton Diamond Film, Northboro, MA (United States); Herk, L. [Southwest Research Inst., Southfield, MI (United States); Hojnacki, H.; Rourk, D. [Intelligent Structures Incorporated, Canton, MI (United States); Kamo, R. [Adiabatics, Inc., Columbus, IN (United States); Nieman, B. [Allied-Signal Inc., Des Plaines, IL (United States); O`Neill, D. [3M, St. Paul, MN (United States); Peterson, M.B. [Wear Sciences, Arnold, MD (United States); Pfaffenberger, G. [Allison Gas Turbine, Indianapolis, IN (United States); Pryor, R.W. [Wayne State Univ., Detroit, MI (United States); Russell, J. [Superconductivity Publications, Inc., Somerset, NJ (United States); Syniuta, W. [Advanced Mechanical Technology, Inc., Newton, MA (United States); Tamor, M. [Ford Motor Co., Dearborn, MI (United States); Vojnovich, T. [Dept. of Energy, Washington, DC (United States); Yarbrough, W. [Pennsylvania State Univ., University Park (United States); Yust, C.S. [Oak Ridge National Lab., TN (United States)

    1993-01-01

    The aim of this group was to compile a listing of current and anticipated future problem areas in the transportation industry where the properties of diamond and DLC films make them especially attractive and where the panel could strongly endorse the establishment of DOE/Transportation Industry cooperative research efforts. This section identifies the problem areas for possible applications of diamond/DLC technology and presents indications of current approaches to these problems.

  20. Strong ideal convergence in probabilistic metric spaces

    Indian Academy of Sciences (India)

    sequence and strong ideal Cauchy sequence in a probabilistic metric (PM) space endowed with the strong topology, and ... also important applications in nonlinear analysis [2]. The theory was brought to ..... for each t > 0 since each set on the right-hand side of the relation (3.1) belongs to I. Thus, by Definition 2.11 and the ...

  1. Large N baryons, strong coupling theory, quarks

    International Nuclear Information System (INIS)

    Sakita, B.

    1984-01-01

    It is shown that in QCD the large N limit is the same as the static strong coupling limit. By using the static strong coupling techniques some of the results of large N baryons are derived. The results are consistent with the large N SU(6) static quark model. (author)

  2. Optimization of strong and weak coordinates

    NARCIS (Netherlands)

    Swart, M.; Bickelhaupt, F.M.

    2006-01-01

    We present a new scheme for the geometry optimization of equilibrium and transition state structures that can be used for both strong and weak coordinates. We use a screening function that depends on atom-pair distances to differentiate strong coordinates from weak coordinates. This differentiation

  3. Strong decays of nucleon and delta resonances

    International Nuclear Information System (INIS)

    Bijker, R.; Leviatan, A.

    1996-01-01

    We study the strong couplings of the nucleon and delta resonances in a collective model. In the ensuing algebraic treatment we derive closed expressions for decay widths which are used to analyze the experimental data for strong decays into the pion and eta channels. (Author)

  4. Theoretical studies of strongly correlated fermions

    Energy Technology Data Exchange (ETDEWEB)

    Logan, D. [Institut Max von Laue - Paul Langevin (ILL), 38 - Grenoble (France)

    1997-04-01

    Strongly correlated fermions are investigated. An understanding of strongly correlated fermions underpins a diverse range of phenomena such as metal-insulator transitions, high-temperature superconductivity, magnetic impurity problems and the properties of heavy-fermion systems, in all of which local moments play an important role. (author).

  5. Seismic switch for strong motion measurement

    Science.gov (United States)

    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. Transport Phenomena.

    Science.gov (United States)

    Shah, D. B.

    1984-01-01

    Describes a course designed to achieve a balance between exposing students to (1) advanced topics in transport phenomena, pointing out similarities and differences between three transfer processes and (2) common methods of solving differential equations. (JN)

  7. Nicaragua - Transportation

    Data.gov (United States)

    Millennium Challenge Corporation — The evaluation examines impacts of the Transportation Project in three ways. First, we calculate economic rates of return associated with reduced user costs for each...

  8. Ocean transportation

    National Research Council Canada - National Science Library

    Frankel, Ernst G; Marcus, Henry S

    1973-01-01

    .... In ocean transportation economics we present investment and operating costs as well as the results of a study of financing of shipping. Similarly, a discussion of government aid to shipping is presented.

  9. Transport service

    CERN Multimedia

    C. Cerruti / FI

    2006-01-01

    A large number of pallet-crates (panières grillagées), which are used for transporting equipment and for removals, have been dispatched to various locations around the CERN site. We kindly request all users who may have such crates in their possession and no longer need them to make the necessary arrangements (EDH request to the Transport Group) to return them to Building 133, as we currently have no more in stock. Claude CERRUTI / FI-PI

  10. RF transport

    CERN Document Server

    Choroba, Stefan

    2013-01-01

    This paper deals with the techniques of transport of high-power radiofrequency (RF) power from a RF power source to the cavities of an accelerator. Since the theory of electromagnetic waves in waveguides and of waveguide components is very well explained in a number of excellent text books it will limit itself on special waveguide distributions and on a number of, although not complete list of, special problems which sometimes occur in RF power transportation systems.

  11. Public transport

    OpenAIRE

    Lethbridge, Jane

    2008-01-01

    Public transport plays an essential role in enabling people from low income and other disadvantaged groups to access employment and services. It also contributes to the development of social networks and social capital, by helping people to visit friends and relatives and take part in community and other social activities. Public policy makers have begun to recognise that adequate public transport provision can play an important role in reducing social exclusion. [Taken from introductory para...

  12. Strong and superstrong pulsed magnetic fields generation

    CERN Document Server

    Shneerson, German A; Krivosheev, Sergey I

    2014-01-01

    Strong pulsed magnetic fields are important for several fields in physics and engineering, such as power generation and accelerator facilities. Basic aspects of the generation of strong and superstrong pulsed magnetic fields technique are given, including the physics and hydrodynamics of the conductors interacting with the field as well as an account of the significant progress in generation of strong magnetic fields using the magnetic accumulation technique. Results of computer simulations as well as a survey of available field technology are completing the volume.

  13. Impurity screening in strongly coupled plasma systems

    CERN Document Server

    Kyrkos, S

    2003-01-01

    We present an overview of the problem of screening of an impurity in a strongly coupled one-component plasma within the framework of the linear response (LR) theory. We consider 3D, 2D and quasi-2D layered systems. For a strongly coupled plasma the LR can be determined by way of the known S(k) structure functions. In general, an oscillating screening potential with local overscreening and antiscreening regions emerges. In the case of the bilayer, this phenomenon becomes global, as overscreening develops in the layer of the impurity and antiscreening in the adjacent layer. We comment on the limitations of the LR theory in the strong coupling situation.

  14. The lambda sigma calculus and strong normalization

    DEFF Research Database (Denmark)

    Schack-Nielsen, Anders; Schürmann, Carsten

    Explicit substitution calculi can be classified into several dis- tinct categories depending on whether they are confluent, meta-confluent, strong normalization preserving, strongly normalizing, simulating, fully compositional, and/or local. In this paper we present a variant of the λσ-calculus......, which satisfies all seven conditions. In particular, we show how to circumvent Mellies counter-example to strong normalization by a slight restriction of the congruence rules. The calculus is implemented as the core data structure of the Celf logical framework. All meta-theoretic aspects of this work...

  15. Sustainable transport studies in Asia

    CERN Document Server

    Zhang, Junyi

    2013-01-01

    This book aims to provide a good understanding of and perspective on sustainable transport in Asia by focusing on economic, environmental, and social sustainability. It is widely acknowledged that the current situation and trends in transport are not always sustainable in Asia, due in part to the fast-growing economy and the astounding speed of urbanization as well as least-mature governance. As essential research material, the book provides strong support for policy makers and planners by comprehensively covering three groups of strategies, characterized by the words “avoid” (e.g., urban form design and control of car ownership), “shift” (e.g., establishing comprehensive transportation systems and increasing public transportation systems for both intracity and intercity travel), and “improve” (e.g., redesign of paratransit system, low-emission vehicles, intelligent transportation systems, and eco-life). These are elaborated in the book alongside consideration of the uncertainty of policy effects ...

  16. Neoclassical transport optimization of LHD

    Energy Technology Data Exchange (ETDEWEB)

    Murakami, S.; Yamada, H.; Watanabe, K.Y. [National Inst. for Fusion Science, Toki, Gifu (Japan); Wakasa, A. [Hokkaido Univ., Graduate School of Engineering, Sapporo, Hokkaido (Japan); Maassberg, H.; Beidler, C.D. [Teilinstitut Greifswald, Max-Planck-Institut fuer Plasmaphysik, Greifswald (Germany)

    2002-06-01

    Neoclassical transport is studied for LHD configurations in which the magnetic axis has been shifted radially by determining the mono-energetic transport coefficient and the effective helical ripple. With respect to the transport in the long mean free path collisionality region - the so called 1/{nu} transport -, the optimum configuration is found when the magnetic axis has a major radius of 3.53m, which is 0.22m inward shifted from the standard'' configuration of LHD. In the optimized case, the effective helical ripple is very small, remaining below 2% inside 4/5 of the plasma radius. This indicates that a strong inward shift of the magnetic axis in the LHD can diminish the neoclassical transport to a level typical of so-called advanced stellarators''. (author)

  17. Strong Coupling Corrections in Quantum Thermodynamics

    Science.gov (United States)

    Perarnau-Llobet, M.; Wilming, H.; Riera, A.; Gallego, R.; Eisert, J.

    2018-03-01

    Quantum systems strongly coupled to many-body systems equilibrate to the reduced state of a global thermal state, deviating from the local thermal state of the system as it occurs in the weak-coupling limit. Taking this insight as a starting point, we study the thermodynamics of systems strongly coupled to thermal baths. First, we provide strong-coupling corrections to the second law applicable to general systems in three of its different readings: As a statement of maximal extractable work, on heat dissipation, and bound to the Carnot efficiency. These corrections become relevant for small quantum systems and vanish in first order in the interaction strength. We then move to the question of power of heat engines, obtaining a bound on the power enhancement due to strong coupling. Our results are exemplified on the paradigmatic non-Markovian quantum Brownian motion.

  18. Finding quantum effects in strong classical potentials

    Science.gov (United States)

    Hegelich, B. Manuel; Labun, Lance; Labun, Ou Z.

    2017-06-01

    The long-standing challenge to describing charged particle dynamics in strong classical electromagnetic fields is how to incorporate classical radiation, classical radiation reaction and quantized photon emission into a consistent unified framework. The current, semiclassical methods to describe the dynamics of quantum particles in strong classical fields also provide the theoretical framework for fundamental questions in gravity and hadron-hadron collisions, including Hawking radiation, cosmological particle production and thermalization of particles created in heavy-ion collisions. However, as we show, these methods break down for highly relativistic particles propagating in strong fields. They must therefore be improved and adapted for the description of laser-plasma experiments that typically involve the acceleration of electrons. Theory developed from quantum electrodynamics, together with dedicated experimental efforts, offer the best controllable context to establish a robust, experimentally validated foundation for the fundamental theory of quantum effects in strong classical potentials.

  19. The Charm and Beauty of Strong Interactions

    Science.gov (United States)

    El-Bennich, Bruno

    2018-01-01

    We briefly review common features and overlapping issues in hadron and flavor physics focussing on continuum QCD approaches to heavy bound states, their mass spectrum and weak decay constants in different strong interaction models.

  20. Atomica ionization by strong coherent radiation

    International Nuclear Information System (INIS)

    Brandi, H.S.; Davidovich, L.

    1979-07-01

    The relation among the three most frequently used non-perturbative methods proposed to study the ionization of atoms by strong electromagnetic fields is established. Their range of validity is also determined. (Author) [pt

  1. Perturbation of an exact strong gravity solution

    International Nuclear Information System (INIS)

    Baran, S.A.

    1982-10-01

    Perturbations of an exact strong gravity solution are investigated. It is shown, by using the new multipole expansions previously presented, that this exact and static spherically symmetric solution is stable under odd parity perturbations. (author)

  2. Strong-force theorists scoop Noble Prize

    CERN Multimedia

    Durrani, Matin

    2004-01-01

    Three US theorists have shared the 2004 Nobel Prize in Physics "for the discovery of asymptotic freedom in the theory of the strong interaction". Their theoretical work explains why quarks behave almost as free particles at high energies (½ page)

  3. Calculating hadronic properties in strong QCD

    International Nuclear Information System (INIS)

    Pennington, M.R.

    1996-01-01

    This talk gives a brief review of the progress that has been made in calculating the properties of hadrons in strong QCD. In keeping with this meeting I will concentrate on those properties that can be studied with electromagnetic probes. Though perturbative QCD is highly successful, it only applies in a limited kinematic regime, where hard scattering occur, and the quarks move in the interaction region as if they are free, pointlike objects. However, the bulk of strong interactions are governed by the long distance regime, where the strong interaction is strong. It is this regime of length scales of the order of a Fermi, that determines the spectrum of light hadrons and their properties. The calculation of these properties requires an understanding of non-perturbative QCD, of confinement and chiral symmetry breaking. (author)

  4. Building strong brands – does it matter?

    OpenAIRE

    Aure, Kristin Gaaseide; Nervik, Kristine Dybvik

    2014-01-01

    Brand equity has proven, through several decades of research, to be a primary source of competitive advantage and future earnings (Yoo & Donthu, 2001). Building strong brands has therefore become a priority for many organizations, with the presumption that building strong brands yields these advantages (Yasin et al., 2007). A quantitative survey was conducted at Sunnmøre in Norway in order to answer the two developed research questions. - Does the brand equity dimensions; brand...

  5. Algebra of strong and electroweak interactions

    International Nuclear Information System (INIS)

    Bolokhov, S.V.; Vladimirov, Yu.S.

    2004-01-01

    The algebraic approach to describing the electroweak and strong interactions is considered within the frames of the binary geometrophysics, based on the principles of the Fokker-Feynman direct interparticle interaction theories of the Kaluza-Klein multidimensional geometrical models and the physical structures theory. It is shown that in this approach the electroweak and strong elementary particles interaction through the intermediate vector bosons, are characterized by the subtypes of the algebraic classification of the complex 3 x 3-matrices [ru

  6. Manipulating light with strongly modulated photonic crystals

    International Nuclear Information System (INIS)

    Notomi, Masaya

    2010-01-01

    Recently, strongly modulated photonic crystals, fabricated by the state-of-the-art semiconductor nanofabrication process, have realized various novel optical properties. This paper describes the way in which they differ from other optical media, and clarifies what they can do. In particular, three important issues are considered: light confinement, frequency dispersion and spatial dispersion. First, I describe the latest status and impact of ultra-strong light confinement in a wavelength-cubic volume achieved in photonic crystals. Second, the extreme reduction in the speed of light is reported, which was achieved as a result of frequency dispersion management. Third, strange negative refraction in photonic crystals is introduced, which results from their unique spatial dispersion, and it is clarified how this leads to perfect imaging. The last two sections are devoted to applications of these novel properties. First, I report the fact that strong light confinement and huge light-matter interaction enhancement make strongly modulated photonic crystals promising for on-chip all-optical processing, and present several examples including all-optical switches/memories and optical logics. As a second application, it is shown that the strong light confinement and slow light in strongly modulated photonic crystals enable the adiabatic tuning of light, which leads to various novel ways of controlling light, such as adiabatic frequency conversion, efficient optomechanics systems, photon memories and photons pinning.

  7. Transport and Deposition of Suspended Soil-Colloids in Saturated Sand Columns

    DEFF Research Database (Denmark)

    Sharma, Anu; Kawamoto, Ken; Møldrup, Per

    2011-01-01

    Understanding colloid mobilization, transport and deposition in the subsurface is a prerequisite for predicting colloid‐facilitated transport of strongly adsorbing contaminants and further developing remedial activities. This study investigated the transport behavior of soil‐colloids extracted from...

  8. Interfacility transports.

    Science.gov (United States)

    Blackwell, Thomas H

    2002-02-01

    Financial pressures exerted by managed care organizations toward hospitals to improve efficiencies and to lower total healthcare costs continue to force physicians and administrators to reevaluate operations and practices. This shifting of risk exposure from insurers to providers has resulted in many mergers, acquisitions, and affiliations, so as to form integrated health systems that reduce repetition and duplication of services. Therefore, as these integrated systems develop, along with the emergence of tertiary care, regional referral, and specialty hospitals, the need for patient transfers between such facilities will expand. The decision to move patients between facilities is a multicomponent process comprising health, safety, financial, and legal concerns. Interfacility transportation of patients has been performed over the past 20 to 30 years. Whereas ground transport services were prominent in the 1970s, air medical programs using helicopters and fixed-wing aircraft have recently become widespread. Both hospital-based and private agencies have continued to develop programs for efficiently and expeditiously transporting critically ill or injured patients, many requiring complex life-support devices. The Practice Management Committee of the American College of Emergency Physicians recently updated the 1990 policy statement on interfacility transfers, and two position statements are available from the National Association of EMS Physicians on criteria for air medical transport and medical direction for interfacility transport services. This review provides an overview of transportation systems and services available and assists physicians in understanding the various modes and characteristics of systems available. Personnel configurations and capabilities, physiological limitations, inherent requirements for equipment and patient preparation, and legal issues involved with transferring patients are also outlined.

  9. Strong Motion Earthquake Data Values of Digitized Strong-Motion Accelerograms, 1933-1994

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Strong Motion Earthquake Data Values of Digitized Strong-Motion Accelerograms is a database of over 15,000 digitized and processed accelerograph records from...

  10. Mechanisms of meridional transport processes in the tropical Atlantic; Mechanismen meridionaler Transportprozesse im tropischen Atlantik

    Energy Technology Data Exchange (ETDEWEB)

    Kroeger, J.

    2001-07-01

    Meridional transport processes of water masses and tracers in the subtropical and tropical Atlantic are investigated using a regional eddy resolving model of the wind driven and thermohaline circulation. Analytical emphasis is on float simulations in the model which, complementary to Eulerian means, represent the Lagrangian view and give further insight into the spreading and pathways of characteristic water masses in this area. In the tropics and subtropics shallow 3-dimensional circulation cells are superimposed on the northward warm water transfer within the deep reaching thermohaline overturning cell (MOC) as part of the global ''Conveyor Belt''. Under present-day climate conditions the model shows that the equatorial thermocline is exclusively ventilated by subsurface flow within the tropical-subtropical cell (STC) of the South Atlantic. Only with a prescribed ''Conveyor-off''-Mode the STC of the North Atlantic contributes to this ventilation process with equal amounts. Throughout the year the interhemispheric transport of surface and central water masses of South Atlantic origin into the Caribbean Sea is dominated by zonal detours to the east as a consequence of the interplay of several retroflection events occuring in the North Atlantic. The eulerian mean flow field in the deep layer postulates the interhemispheric mass transport into the South Atlantic to be confined entirely to the western boundary, whereas Lagrangian means indicate intermittent eastward excursions along the equator, related to seasonally alternating zonal currents due to long Rossby waves. It was suggested that the observed characteristic eastward maximum of tracer concentrations along the equator is a consequence of rectifying effects of single or interacting equatorial waves. The model does not validate this hypothesis. The response to transport anomalies of subpolar origin and long periodicity is subject to different time-scales in both

  11. The extended reciprocity: Strong belief outperforms persistence.

    Science.gov (United States)

    Kurokawa, Shun

    2017-05-21

    The existence of cooperation is a mysterious phenomenon and demands explanation, and direct reciprocity is one key potential explanation for the evolution of cooperation. Direct reciprocity allows cooperation to evolve for cooperators who switch their behavior on the basis of information about the opponent's behavior. Here, relevant to direct reciprocity is information deficiency. When the opponent's last move is unknown, how should players behave? One possibility is to choose cooperation with some default probability without using any further information. In fact, our previous paper (Kurokawa, 2016a) examined this strategy. However, there might be beneficial information other than the opponent's last move. A subsequent study of ours (Kurokawa, 2017) examined the strategy which uses the own last move when the opponent's last move is unknown, and revealed that referring to the own move and trying to imitate it when information is absent is beneficial. Is there any other beneficial information else? How about strong belief (i.e., have infinite memory and believe that the opponent's behavior is unchanged)? Here, we examine the evolution of strategies with strong belief. Analyzing the repeated prisoner's dilemma game and using evolutionarily stable strategy (ESS) analysis against an invasion by unconditional defectors, we find the strategy with strong belief is more likely to evolve than the strategy which does not use information other than the opponent player's last move and more likely to evolve than the strategy which uses not only the opponent player's last move but also the own last move. Strong belief produces the extended reciprocity and facilitates the evolution of cooperation. Additionally, we consider the two strategies game between strategies with strong belief and any strategy, and we consider the four strategies game in which unconditional cooperators, unconditional defectors, pessimistic reciprocators with strong belief, and optimistic reciprocators with

  12. Travel and transport

    DEFF Research Database (Denmark)

    Bill, Jan; Roesdahl, Else

    2007-01-01

    On the interrelationship between travel, transport and society; on land transport, sea and river transport, and on winter transport;  on the related technologies and their developments......On the interrelationship between travel, transport and society; on land transport, sea and river transport, and on winter transport;  on the related technologies and their developments...

  13. Optimal transport

    CERN Document Server

    Eckmann, B

    2008-01-01

    At the close of the 1980s, the independent contributions of Yann Brenier, Mike Cullen and John Mather launched a revolution in the venerable field of optimal transport founded by G Monge in the 18th century, which has made breathtaking forays into various other domains of mathematics ever since. The author presents a broad overview of this area.

  14. Transport fuel

    DEFF Research Database (Denmark)

    Ronsse, Frederik; Jørgensen, Henning; Schüßler, Ingmar

    2014-01-01

    Worldwide, the use of transport fuel derived from biomass increased four-fold between 2003 and 2012. Mainly based on food resources, these conventional biofuels did not achieve the expected emission savings and contributed to higher prices for food commod - ities, especially maize and oilseeds...

  15. Nuclear transport

    International Nuclear Information System (INIS)

    Anon.

    2001-01-01

    Here is given the decree (2001/1199) of the 10. of december 2001 relative to the passing of safety rules concerning the maritime transport of spent fuels, plutonium and high-level radioactive wastes contained in packages. (O.M.)

  16. Transport system

    NARCIS (Netherlands)

    Drenth, K.F.

    1999-01-01

    The transport system comprises at least one road surface (2) and at least one vehicle (4) on wheels (6). The road surface (2) has a substantially bowl-shaped cross section and the vehicle (4) is designed so that the wheels (6) run directly on the road surface (2) while the road surface (2) acts as a

  17. A strongly coupled quark-gluon plasma

    Energy Technology Data Exchange (ETDEWEB)

    Shuryak, Edward [Department of Physics and Astronomy, University at Stony Brook, NY 11794 (United States)

    2004-08-01

    Successful description of robust collective flow phenomena at RHIC by ideal hydrodynamics, recent observations of bound c-barc,q-barq states on the lattice, and other theoretical developments indicate that QGP produced at RHIC, and probably in a wider temperature region T{sub c} < T < 4T{sub c}, is not a weakly coupled quasiparticle gas as believed previously. We discuss how strong the interaction is and why it seems to generate hundreds of binary channels with bound states, surviving well inside the QGP phase. We in particular discuss their effect on pressure and viscosity. We conclude by reviewing the similar phenomena for other 'strongly coupled systems', such as (i) strongly coupled supersymmetric theories studied via Maldacena duality; (ii) trapped ultra-cold atoms with very large scattering length, tuned to Feschbach resonances.

  18. Strong Coupling between Plasmons and Organic Semiconductors

    Directory of Open Access Journals (Sweden)

    Joel Bellessa

    2014-05-01

    Full Text Available In this paper we describe the properties of organic material in strong coupling with plasmon, mainly based on our work in this field of research. The strong coupling modifies the optical transitions of the structure, and occurs when the interaction between molecules and plasmon prevails on the damping of the system. We describe the dispersion relation of different plasmonic systems, delocalized and localized plasmon, coupled to aggregated dyes and the typical properties of these systems in strong coupling. The modification of the dye emission is also studied. In the second part, the effect of the microscopic structure of the organics, which can be seen as a disordered film, is described. As the different molecules couple to the same plasmon mode, an extended coherent state on several microns is observed.

  19. A theory of the strong interactions

    International Nuclear Information System (INIS)

    Gross, D.J.

    1979-01-01

    The most promising candidate for a fundamental microscopic theory of the strong interactions is a gauge theory of colored quarks-Quantum Chromodynamics (QCD). There are many excellent reasons for believing in this theory. It embodies the broken symmetries, SU(3) and chiral SU(3)xSU(3), of the strong interactions and reflects the success of (albeit crude) quark models in explaining the spectrum of the observed hadrons. The hidden quantum number of color, necessary to account for the quantum numbers of the low lying hadrons, plays a fundamental role in this theory as the SU(3) color gauge vector 'gluons' are the mediators of the strong interactions. The absence of physical quark states can be 'explained' by the hypothesis of color confinement i.e. that hadrons are permanently bound in color singlet bound states. Finally this theory is unique in being asymptotically free, thus accounting for the almost free field theory behvior of quarks observed at short distances. (Auth.)

  20. Electromagnetic processes in strong crystalline fields

    CERN Multimedia

    2007-01-01

    We propose a number of new investigations on aspects of radiation from high energy electron and positron beams (10-300 GeV) in single crystals and amorphous targets. The common heading is radiation emission by electrons and positrons in strong electromagnetic fields, but as the setup is quite versatile, other related phenomena in radiation emission can be studied as well. The intent is to clarify the role of a number of important aspects of radiation in strong fields as e.g. observed in crystals. We propose to measure trident 'Klein-like' production in strong crystalline fields, 'crystalline undulator' radiation, 'sandwich' target phenomena, LPM suppression of pair production as well as axial and planar effects in contributions of spin to the radiation.

  1. Patterns of Strong Coupling for LHC Searches

    CERN Document Server

    Liu, Da; Rattazzi, Riccardo; Riva, Francesco

    2016-11-23

    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. Our construction provides the so far unique structurally robust context where to motivate several searches in Higgs physics, d...

  2. Electronic Structure of Strongly Correlated Materials

    CERN Document Server

    Anisimov, Vladimir

    2010-01-01

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

  3. Aperture averaging in strong oceanic turbulence

    Science.gov (United States)

    Gökçe, Muhsin Caner; Baykal, Yahya

    2018-04-01

    Receiver aperture averaging technique is employed in underwater wireless optical communication (UWOC) systems to mitigate the effects of oceanic turbulence, thus to improve the system performance. The irradiance flux variance is a measure of the intensity fluctuations on a lens of the receiver aperture. Using the modified Rytov theory which uses the small-scale and large-scale spatial filters, and our previously presented expression that shows the atmospheric structure constant in terms of oceanic turbulence parameters, we evaluate the irradiance flux variance and the aperture averaging factor of a spherical wave in strong oceanic turbulence. Irradiance flux variance variations are examined versus the oceanic turbulence parameters and the receiver aperture diameter are examined in strong oceanic turbulence. Also, the effect of the receiver aperture diameter on the aperture averaging factor is presented in strong oceanic turbulence.

  4. Electromagnetic Processes in strong Crystalline Fields

    CERN Multimedia

    2007-01-01

    We propose a number of new investigations on aspects of radiation from high energy electron and positron beams (10-300 GeV) in single crystals and amorphous targets. The common heading is radiation emission by electrons and positrons in strong electromagnetic fields, but as the setup is quite versatile, other related phenomena in radiation emission can be studied as well. The intent is to clarify the role of a number of important aspects of radiation in strong fields as e.g. observed in crystals. We propose to measure trident 'Klein-like' production in strong crystalline fields, 'crystalline undulator' radiation, 'sandwich' target phenomena, LPM suppression of pair production as well as axial and planar effects in contributions of spin to the radiation.

  5. Experimental investigation of strong field trident production

    CERN Document Server

    Esberg, J; Knudsen, H; Thomsen, H D; Uggerhøj, E; Uggerhøj, U I; Sona, P; Mangiarotti, A; Ketel, T J; Dizdar, A; Dalton, M M; Ballestrero, S; Connell, S H

    2010-01-01

    We show by experiment that an electron impinging on an electric field that is of critical magnitude in its rest frame, may produce an electron-positron pair. Our measurements address higher-order QED, using the strong electric fields obtainable along particular crystallographic directions in single crystals. For the amorphous material our data are in good agreement with theory, whereas a discrepancy with theory on the magnitude of the trident enhancement is found in the precisely aligned case where the strong electric field acts.

  6. Gluon scattering amplitudes at strong coupling

    Energy Technology Data Exchange (ETDEWEB)

    Alday, Luis F. [Institute for Theoretical Physics and Spinoza Institute, Utrecht University, 3508 TD Utrecht (Netherlands); Maldacena, Juan [School of Natural Sciences, Institute for Advanced Study, Princeton, NJ 08540 (United States)

    2007-06-15

    We describe how to compute planar gluon scattering amplitudes at strong coupling in N = 4 super Yang Mills by using the gauge/string duality. The computation boils down to finding a certain classical string configuration whose boundary conditions are determined by the gluon momenta. The results are infrared divergent. We introduce the gravity version of dimensional regularization to define finite quantities. The leading and subleading IR divergencies are characterized by two functions of the coupling that we compute at strong coupling. We compute also the full finite form for the four point amplitude and we find agreement with a recent ansatz by Bern, Dixon and Smirnov.

  7. Strong boundedness of analytic functions in tubes

    Directory of Open Access Journals (Sweden)

    Richard D. Carmichael

    1979-01-01

    Full Text Available Certain classes of analytic functions in tube domains TC=ℝn+iC in n-dimensional complex space, where C is an open connected cone in ℝn, are studied. We show that the functions have a boundedness property in the strong topology of the space of tempered distributions g′. We further give a direct proof that each analytic function attains the Fourier transform of its spectral function as distributional boundary value in the strong (and weak topology of g′.

  8. Including virtual photons in strong interactions

    International Nuclear Information System (INIS)

    Rusetsky, A.

    2003-01-01

    In the perturbative field-theoretical models we investigate the inclusion of the electromagnetic interactions into the purely strong theory that describes hadronic processes. In particular, we study the convention for splitting electromagnetic and strong interactions and the ambiguity of such a splitting. The issue of the interpretation of the parameters of the low-energy effective field theory in the presence of electromagnetic interactions is addressed, as well as the scale and gauge dependence of the effective theory couplings. We hope, that the results of these studies are relevant for the electromagnetic sector of ChPT. (orig.)

  9. Thermodynamical instabilities under strong magnetic fields

    Science.gov (United States)

    Chen, Y. J.

    2017-03-01

    The thermodynamical instabilities of low densities in the n p matter and n p e matter are studied within several relativistic nuclear models under some values of magnetic fields. The results are compared between each other and the effects of the symmetry energy slope at saturation density on the instability are investigated. The instability regions can exhibit bands due to the presence of Landau levels for very strong magnetic fields of the order of 1017 G, while for weaker magnetic fields, the bands are replaced by many diffused or scattered pieces. It also shows that the proton fraction in the inner crust of neutron stars may be complex under strong magnetic fields.

  10. Universal behavior of strongly correlated Fermi systems

    Energy Technology Data Exchange (ETDEWEB)

    Shaginyan, Vasilii R [B.P. Konstantinov St. Petersburg Institute of Nuclear Physics, Russian Academy of Sciences, Gatchina, Leningrad region, Rusian Federation (Russian Federation); Amusia, M Ya [A.F. Ioffe Physico-Technical Institute, Russian Academy of Sciences, St. Petersburg (Russian Federation); Popov, Konstantin G [Komi Scientific Center, Ural Branch of the Russian Academy of Sciences, Syktyvkar (Russian Federation)

    2007-06-30

    This review discusses the construction of a theory and the analysis of phenomena occurring in strongly correlated Fermi systems such as high-T{sub c} superconductors, heavy-fermion metals, and quasi-two-dimensional Fermi systems. It is shown that the basic properties and the universal behavior of strongly correlated Fermi systems can be described in the framework of the Fermi-condensate quantum phase transition and the well-known Landau paradigm of quasiparticles and the order parameter. The concept of fermion condensation may be fruitful in studying neutron stars, finite Fermi systems, ultra-cold gases in traps, and quark plasma. (reviews of topical problems)

  11. Universal behavior of strongly correlated Fermi systems

    International Nuclear Information System (INIS)

    Shaginyan, Vasilii R; Amusia, M Ya; Popov, Konstantin G

    2007-01-01

    This review discusses the construction of a theory and the analysis of phenomena occurring in strongly correlated Fermi systems such as high-T c superconductors, heavy-fermion metals, and quasi-two-dimensional Fermi systems. It is shown that the basic properties and the universal behavior of strongly correlated Fermi systems can be described in the framework of the Fermi-condensate quantum phase transition and the well-known Landau paradigm of quasiparticles and the order parameter. The concept of fermion condensation may be fruitful in studying neutron stars, finite Fermi systems, ultra-cold gases in traps, and quark plasma. (reviews of topical problems)

  12. Analytical solution of strongly nonlinear Duffing oscillators

    OpenAIRE

    El-Naggar, A.M.; Ismail, G.M.

    2016-01-01

    In this paper, a new perturbation technique is employed to solve strongly nonlinear Duffing oscillators, in which a new parameter α=α(ε)α=α(ε) is defined such that the value of α is always small regardless of the magnitude of the original parameter εε. Therefore, the strongly nonlinear Duffing oscillators with large parameter ε are transformed into a small parameter system with respect to αα. Approximate solution obtained by the present method is compared with the solution of energy balance m...

  13. De Sitter vacua of strongly interacting QFT

    Energy Technology Data Exchange (ETDEWEB)

    Buchel, Alex [Department of Applied Mathematics, University of Western Ontario,London, Ontario N6A 5B7 (Canada); Department of Physics and Astronomy, University of Western Ontario,London, Ontario N6A 5B7 (Canada); Perimeter Institute for Theoretical Physics,Waterloo, Ontario N2J 2W9 (Canada); Karapetyan, Aleksandr [Department of Applied Mathematics, University of Western Ontario,London, Ontario N6A 5B7 (Canada)

    2017-03-22

    We use holographic correspondence to argue that Euclidean (Bunch-Davies) vacuum is a late-time attractor of the dynamical evolution of quantum gauge theories at strong coupling. The Bunch-Davies vacuum is not an adiabatic state, if the gauge theory is non-conformal — the comoving entropy production rate is nonzero. Using the N=2{sup ∗} gauge theory holography, we explore prospects of explaining current accelerated expansion of the Universe as due to the vacuum energy of a strongly coupled QFT.

  14. Electron transport in wurtzite InN

    Indian Academy of Sciences (India)

    It is found that the maximum peak velocity only occurs when the electric field is increased to a value above a certain critical field. This critical field is strongly dependent on InN parameters. The steady-state transport parameters are in fair agreement with other recent calculations. Keywords. InN transport; mobility; energy and ...

  15. Alterações na coerência cortical inter-hemisférica produzidas pela estimulação elétrica funcional (FES Changes in cortical interhemispheric coherence produced by functional electrical stimulation (FES

    Directory of Open Access Journals (Sweden)

    Letícia Ecard

    2007-06-01

    Full Text Available O presente estudo teve como objetivo observar alterações corticais produzidas pela estimulação elétrica funcional (FES, através da eletrencefalografia quantitativa (EEGq. Simultaneamente à captação do sinal eletrencefalográfico, realizou-se uma eletroestimulação no antebraço direito para estimulaç��o da extensão do indicador. A amostra consistiu de 45 sujeitos randomizados em 3 grupos de 15. O grupo controle foi submetido a 24 blocos de estimulação com intensidade de corrente zero. O grupo 1 foi submetido a 24 blocos e o grupo 2 a 36 blocos. A coerência entre os pares de eletrodos F3-F4, C3-C4 e P3-P4 foi analisada ao longo dos grupos através de avaliação estatística. Os resultados apontaram para um aumento da coerência inter-hemisférica após a eletroestimulação.The aim of the present study was to observe cortical alterations produced by functional electrical stimulation (FES, through quantitative electroencephalography (qEEG. Electrostimulation was performed on the right forearm to stimulate the extension of the index finger. EEG activity was recorded simultaneously. The sample consisted of 45 subjects randomly divided into 3 groups of 15 subjects each. The control group was submitted to 24 blocks of stimulation at a current intensity of zero. Group 1 was submitted to 24 blocks and group 2 to 36 blocks. Interhemispheric coherence between F3-F4, C3-C4 and P3-P4 was assessed through a statistical analysis. Results pointed out to increased coherence values after stimulation.

  16. Mid-Holocene monsoons: a multi-model analysis of the inter-hemispheric differences in the responses to orbital forcing and ocean feedbacks

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Y. [University of Bristol, School of Geographical Sciences, Bristol (United Kingdom); Laboratoire des Sciences du Climat et de l' Environment, CEA/CNRS/UVSQ, Saclay (France); Harrison, S.P. [University of Bristol, School of Geographical Sciences, Bristol (United Kingdom); Macquarie University, School of Biological Sciences, North Ryde, NSW (Australia)

    2012-09-15

    The response of monsoon circulation in the northern and southern hemisphere to 6 ka orbital forcing has been examined in 17 atmospheric general circulation models and 11 coupled ocean-atmosphere general circulation models. The atmospheric response to increased summer insolation at 6 ka in the northern subtropics strengthens the northern-hemisphere summer monsoons and leads to increased monsoonal precipitation in western North America, northern Africa and China; ocean feedbacks amplify this response and lead to further increase in monsoon precipitation in these three regions. The atmospheric response to reduced summer insolation at 6 ka in the southern subtropics weakens the southern-hemisphere summer monsoons and leads to decreased monsoonal precipitation in northern South America, southern Africa and northern Australia; ocean feedbacks weaken this response so that the decrease in rainfall is smaller than might otherwise be expected. The role of the ocean in monsoonal circulation in other regions is more complex. There is no discernable impact of orbital forcing in the monsoon region of North America in the atmosphere-only simulations but a strong increase in precipitation in the ocean-atmosphere simulations. In contrast, there is a strong atmospheric response to orbital forcing over northern India but ocean feedback reduces the strength of the change in the monsoon although it still remains stronger than today. Although there are differences in magnitude and exact location of regional precipitation changes from model to model, the same basic mechanisms are involved in the oceanic modulation of the response to orbital forcing and this gives rise to a robust ensemble response for each of the monsoon systems. Comparison of simulated and reconstructed changes in regional climate suggest that the coupled ocean-atmosphere simulations produce more realistic changes in the northern-hemisphere monsoons than atmosphere-only simulations, though they underestimate the

  17. Strong asymmetry of hemispheric climates during MIS-13 inferred from correlating China loess and Antarctica ice records

    Directory of Open Access Journals (Sweden)

    Z. T. Guo

    2009-02-01

    Full Text Available We correlate the China loess and Antarctica ice records to address the inter-hemispheric climate link over the past 800 ka. The results show a broad coupling between Asian and Antarctic climates at the glacial-interglacial scale. However, a number of decoupled aspects are revealed, among which marine isotope stage (MIS 13 exhibits a strong anomaly compared with the other interglacials. It is characterized by unusually positive benthic oxygen (δ18O and carbon isotope (δ13C values in the world oceans, cooler Antarctic temperature, lower summer sea surface temperature in the South Atlantic, lower CO2 and CH4 concentrations, but by extremely strong Asian, Indian and African summer monsoons, weakest Asian winter monsoon, and lowest Asian dust and iron fluxes. Pervasive warm conditions were also evidenced by the records from northern high-latitude regions. These consistently indicate a warmer Northern Hemisphere and a cooler Southern Hemisphere, and hence a strong asymmetry of hemispheric climates during MIS-13. Similar anomalies of lesser extents also occurred during MIS-11 and MIS-5e. Thus, MIS-13 provides a case that the Northern Hemisphere experienced a substantial warming under relatively low concentrations of greenhouse gases. It suggests that the global climate system possesses a natural variability that is not predictable from the simple response of northern summer insolation and atmospheric CO2 changes. During MIS-13, both hemispheres responded in different ways leading to anomalous continental, marine and atmospheric conditions at the global scale. The correlations also suggest that the marine δ18O record is not always a reliable indicator of the northern ice-volume changes, and that the asymmetry of hemispheric climates is one of the prominent factors controlling the strength of Asian, Indian and African monsoon circulations, most likely through modulating the position of

  18. Earthquake source model using strong motion displacement

    Indian Academy of Sciences (India)

    The strong motion displacement records available during an earthquake can be treated as the response of the earth as the a structural system to unknown forces acting at unknown locations. Thus, if the part of the earth participating in ground motion is modelled as a known finite elastic medium, one can attempt to model the ...

  19. Vector mesons in strongly interacting matter

    Indian Academy of Sciences (India)

    probes like photons, pions or protons or the heated and compressed hadronic matter generated in a heavy-ion collision. Leaving any nuclear medium without strong final-state interactions, dileptons are the optimum decay channel as they avoid any final-state distortion of the 4- momenta of the decay products entering eq.

  20. Vector mesons in strongly interacting matter

    Indian Academy of Sciences (India)

    Properties of hadrons in strongly interacting matter provide a link between quantum chromodynamics in the ... Top: Spectral function of the ρ-meson at normal nuclear matter density as a function of mass and ... directly but folded with the branching ratio ΓV →p1+p2 /Γtot into the specific final channel one is investigating.

  1. Strong industrial base vital for economic revival

    CERN Multimedia

    2001-01-01

    At the inauguration of a 2-day conference on nuclear technology in Islamabad, the chairman of PAEC said that Pakistan needs to develop a strong industrial base and capability to export equipment to improve the economic condition of the country. He descibed how Pakistan has already had a breakthrough with the export of equipment to CERN, Geneva (1 page).

  2. Chaos desynchronization in strongly coupled systems

    International Nuclear Information System (INIS)

    Wu Ye; Liu Weiqing; Xiao, Jinghua; Zhan Meng

    2007-01-01

    The dynamics of chaos desynchronization in strongly coupled oscillator systems is studied. We find a new bifurcation from synchronous chaotic state, chaotic short wave bifurcation, i.e. a chaotic desynchronization attractor is new born in the systems due to chaos desynchronization. In comparison with the usual periodic short wave bifurcation, very rich but distinct phenomena are observed

  3. Strong wind climatic zones in South Africa

    CSIR Research Space (South Africa)

    Kruger, AC

    2010-01-01

    Full Text Available In this paper South Africa is divided into strong wind climate zones, which indicate the main sources of annual maximum wind gusts. By the analysis of wind gust data of 94 weather stations, which had continuous climate time series of 10 years...

  4. Reducing Weak to Strong Bisimilarity in CCP

    Directory of Open Access Journals (Sweden)

    Andrés Aristizábal

    2012-12-01

    Full Text Available Concurrent constraint programming (ccp is a well-established model for concurrency that singles out the fundamental aspects of asynchronous systems whose agents (or processes evolve by posting and querying (partial information in a global medium. Bisimilarity is a standard behavioural equivalence in concurrency theory. However, only recently a well-behaved notion of bisimilarity for ccp, and a ccp partition refinement algorithm for deciding the strong version of this equivalence have been proposed. Weak bisimiliarity is a central behavioural equivalence in process calculi and it is obtained from the strong case by taking into account only the actions that are observable in the system. Typically, the standard partition refinement can also be used for deciding weak bisimilarity simply by using Milner's reduction from weak to strong bisimilarity; a technique referred to as saturation. In this paper we demonstrate that, because of its involved labeled transitions, the above-mentioned saturation technique does not work for ccp. We give an alternative reduction from weak ccp bisimilarity to the strong one that allows us to use the ccp partition refinement algorithm for deciding this equivalence.

  5. Strong motion duration and earthquake magnitude relationships

    International Nuclear Information System (INIS)

    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

  6. Morphological modelling of strongly curved islands

    NARCIS (Netherlands)

    Roelvink, D.; Den Heijer, C.; Van Thiel De Vries, J.S.M.

    2013-01-01

    Land reclamations and island coasts often involve strongly curved shorelines, which are challenging to be properly modeled by numerical morphological models. Evaluation of the long term development of these types of coasts as well as their response to storm conditions requires proper representation

  7. Nonlinear Electron Waves in Strongly Magnetized Plasmas

    DEFF Research Database (Denmark)

    Pécseli, Hans; Juul Rasmussen, Jens

    1980-01-01

    Weakly nonlinear dispersive electron waves in strongly magnetized plasma are considered. A modified nonlinear Schrodinger equation is derived taking into account the effect of particles resonating with the group velocity of the waves (nonlinear Landau damping). The possibility of including the ion...

  8. Strong and Reversible Monovalent Supramolecular Protein Immobilization

    NARCIS (Netherlands)

    Young, Jacqui F.; Nguyen, Hoang D.; Yang, Lanti; Huskens, Jurriaan; Jonkheijm, Pascal; Brunsveld, Luc

    2010-01-01

    Proteins with an iron clasp: Site-selective incorporation of a ferrocene molecule into a protein allows for easy, strong, and reversible supramolecular protein immobilization through a selective monovalent interaction of the ferrocene with a cucurbit[7]uril immobilized on a gold surface. The

  9. Experimental investigation of strong field trident production

    NARCIS (Netherlands)

    Esberg, J.; Kirsebom, K.; Knudsen, H.; Thomsen, H.D.; Uggerhøj, E.; Uggerhøj, U.I.; Sona, P.; Mangiarotti, A.; Ketel, T.J.; Ditzdar, A.; Dalton, M.M.; Ballestrero, S.; Connell, S.H.

    2010-01-01

    We show by experiment that an electron impinging on an electric field that is of critical magnitude in its rest frame, may produce an electron-positron pair. Our measurements address higher-order QED, using the strong electric fields obtainable along particular crystallographic directions in single

  10. Strong-coupling diffusion in relativistic systems

    Indian Academy of Sciences (India)

    hanced values needed to interpret the data at higher energies point towards the importance of strong-coupling effects. ... when all secondary particles have been created. For short times in the initial phase ... It is decisive for a proper representation of the available data for relativistic heavy-ion collisions at and beyond SPS.

  11. Bottomonia: open bottom strong decays and spectrum

    Directory of Open Access Journals (Sweden)

    Santopinto E.

    2014-05-01

    Full Text Available We present our results for the bottomonium spectrum with self energy corrections. The bare masses used in the calculation are computed within Godfrey and Isgur’s relativized quark model. We also discuss our results for the open bottom strong decay widths of higher bottomonia in the 3P0 pair-creation model.

  12. Strong motion duration and earthquake magnitude relationships

    Energy Technology Data Exchange (ETDEWEB)

    Salmon, M.W.; Short, S.A. [EQE International, Inc., San Francisco, CA (United States); Kennedy, R.P. [RPK Structural Mechanics Consulting, Yorba Linda, CA (United States)

    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.

  13. Controlling Josephson dynamics by strong microwave fields

    NARCIS (Netherlands)

    Chesca, B.; Savel'ev, E.; Rakhmanov, A.L.; Smilde, H.J.H.; Hilgenkamp, Johannes W.M.

    2008-01-01

    We observe several sharp changes in the slope of the current-voltage characteristics (CVCs) of thin-film ramp-edge Josephson junctions between YBa2Cu3O7−delta and Nb when applying strong microwave fields. Such behavior indicates an intriguing Josephson dynamics associated with the switching from a

  14. Strong-coupling diffusion in relativistic systems

    Indian Academy of Sciences (India)

    Different from the early universe, heavy-ion collisions at very high energies do not reach statistical equilibrium, although thermal models explain many of their features. To account for nonequilibrium strong-coupling effects, a Fokker–Planck equation with time-dependent diffusion coefficient is proposed. A schematic model ...

  15. Weak and strong nonlinearities in magnetic bearings

    Czech Academy of Sciences Publication Activity Database

    Půst, Ladislav

    2004-01-01

    Roč. 39, č. 7 (2004), s. 779-795 ISSN 0094-114X R&D Projects: GA ČR GA101/00/1471; GA AV ČR IBS2076301 Institutional research plan: CEZ:AV0Z2076919 Keywords : weak nonlinearitiy * strong nonlinearity * magnetics bearings Subject RIV: BI - Acoustics Impact factor: 0.605, year: 2004

  16. Rotating compressible fluids under strong stratification

    Czech Academy of Sciences Publication Activity Database

    Feireisl, Eduard; Lu, Y.; Novotný, A.

    2014-01-01

    Roč. 19, October (2014), s. 11-18 ISSN 1468-1218 Keywords : rotating fluid * compressible Navier-Stokes * strong stratification Subject RIV: BA - General Mathematics Impact factor: 2.519, year: 2014 http://www.sciencedirect.com/science/article/pii/S1468121814000212#

  17. Super-strong Magnetic Field in Sunspots

    Science.gov (United States)

    Okamoto, Takenori J.; Sakurai, Takashi

    2018-01-01

    Sunspots are the most notable structure on the solar surface with strong magnetic fields. The field is generally strongest in a dark area (umbra), but sometimes stronger fields are found in non-dark regions, such as a penumbra and a light bridge. The formation mechanism of such strong fields outside umbrae is still puzzling. Here we report clear evidence of the magnetic field of 6250 G, which is the strongest field among Stokes I profiles with clear Zeeman splitting ever observed on the Sun. The field was almost parallel to the solar surface and located in a bright region sandwiched by two opposite-polarity umbrae. Using a time series of spectral data sets, we discuss the formation process of the super-strong field and suggest that this strong field region was generated as a result of compression of one umbra pushed by the horizontal flow from the other umbra, such as the subduction of the Earth’s crust in plate tectonics.

  18. Strongly coupled semidirect mediation of supersymmetry breaking

    International Nuclear Information System (INIS)

    Ibe, M.; Izawa, K.-I.; Nakai, Y.

    2009-01-01

    Strongly coupled semidirect gauge mediation models of supersymmetry breaking through massive mediators with standard-model charges are investigated by means of composite degrees of freedom. Sizable mediation is realized to generate the standard-model gaugino masses for a small mediator mass without breaking the standard-model symmetries.

  19. A Note on Strongly Dense Matrices

    Czech Academy of Sciences Publication Activity Database

    Fiedler, Miroslav; Hall, F.J.

    2015-01-01

    Roč. 1, č. 4 (2015), s. 721-730 ISSN 2199-675X Institutional support: RVO:67985807 Keywords : strongly dense matrix * Boolean matrix * nonnegative matrix * idempotent matrix * intrinsic product * generalized complementary basic matrix Subject RIV: BA - General Mathematics

  20. Strongly 2-connected orientations of graphs

    DEFF Research Database (Denmark)

    Thomassen, Carsten

    2014-01-01

    We prove that a graph admits a strongly 2-connected orientation if and only if it is 4-edge-connected, and every vertex-deleted subgraph is 2-edge-connected. In particular, every 4-connected graph has such an orientation while no cubic 3-connected graph has such an orientation....

  1. Copper transport.

    Science.gov (United States)

    Linder, M C; Wooten, L; Cerveza, P; Cotton, S; Shulze, R; Lomeli, N

    1998-05-01

    In adult humans, the net absorption of dietary copper is approximately 1 mg/d. Dietary copper joins some 4-5 mg of endogenous copper flowing into the gastrointestinal tract through various digestive juices. Most of this copper returns to the circulation and to the tissues (including liver) that formed them. Much lower amounts of copper flow into and out of other major parts of the body (including heart, skeletal muscle, and brain). Newly absorbed copper is transported to body tissues in two phases, borne primarily by plasma protein carriers (albumin, transcuprein, and ceruloplasmin). In the first phase, copper goes from the intestine to the liver and kidney; in the second phase, copper usually goes from the liver (and perhaps also the kidney) to other organs. Ceruloplasmin plays a role in this second phase. Alternatively, liver copper can also exit via the bile, and in a form that is less easily reabsorbed. Copper is also present in and transported by other body fluids, including those bathing the brain and central nervous system and surrounding the fetus in the amniotic sac. Ceruloplasmin is present in these fluids and may also be involved in copper transport there. The concentrations of copper and ceruloplasmin in milk vary with lactational stage. Parallel changes occur in ceruloplasmin messenger RNA expression in the mammary gland (as determined in pigs). Copper in milk ceruloplasmin appears to be particularly available for absorption, at least in rats.

  2. Strongly correlated electron physics in nanotube-encapsulated metallocene chains

    Science.gov (United States)

    García-Suárez, V. M.; Ferrer, J.; Lambert, C. J.

    2006-11-01

    The structural, electronic, and transport properties of metallocene molecules (MCp2) and isolated or nanotube-encapsulated metallocene chains are studied by using a combination of density functional theory and nonequilibrium Green’s functions. The analysis first discusses the whole series of isolated (MCp2) molecules, where M=V , Cr, Mn, Fe, Co, Ni, Ru, and Os. The series presents a rich range of electronic and magnetic behaviors due to the interplay between the crystal field interaction and Hund’s rules, as the occupation of the d shell increases. The article then shows how many of these interesting properties can also be seen when (MCp2) molecules are linked together to form periodic chains. Interestingly, a large portion of these chains display metallic, and eventually magnetic, behavior. These properties may render these systems as useful tools for spintronics applications but this is hindered by the lack of mechanical stability of the chains. It is finally argued that encapsulation of the chains inside carbon nanotubes, that is exothermic for radii larger than 4.5Å , provides the missing mechanical stability and electrical isolation. The structural stability, charge transfer, magnetic, and electronic behavior of the ensuing chains, as well as the modification of the electrostatic potential in the nanotube wall produced by the metallocenes are thoroughly discussed. We argue that the full devices can be characterized by two doped, strongly correlated Hubbard models whose mutual hybridization is almost negligible. The charge transferred from the chains produces a strong modification of the electrostatic potential in the nanotube walls, which is amplified in case of semiconducting and endothermic nanotubes. The transport properties of isolated metallocenes between semi-infinite nanotubes are also analyzed and shown to lead to important changes in the transmission coefficients of clean nanotubes for high energies.

  3. Strong ground motion prediction using virtual earthquakes.

    Science.gov (United States)

    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. Strong negative terahertz photoconductivity in photoexcited graphene

    Science.gov (United States)

    Fu, Maixia; Wang, Xinke; Ye, Jiasheng; Feng, Shengfei; Sun, Wenfeng; Han, Peng; Zhang, Yan

    2018-01-01

    Terahertz (THz) response of a chemical vapor deposited graphene on a quartz substrate has been investigated by using an ultrafast optical-pump THz-probe spectroscopy. Without photoexcitation, the frequency-dependence optical conductivity shows a strong carrier response owing to the intrinsically doped graphene. Upon photoexcitation, an enhancement in THz transmission is observed and the transmission increases nonlinearly with the increase of pump power, which is rooted in a reduction of intrinsic conductivity arising from the strong enhancement of carrier scattering rather than THz emission occurrence. The modulation depth of 18.8% was experimentally achieved, which is more than four times greater than that of the previous reported. The photoinduced response here highlights the variety of response possible in graphene depending on the sample quality, carrier mobility and doping level. The graphene provides promising applications in high-performance THz modulators and THz photoelectric devices.

  5. Cosmological applications of strong gravitational lensing

    DEFF Research Database (Denmark)

    Paraficz, Danuta

    value of the energy density of the two above components, together with measuring the Hubble constant that determines the age of the Universe, is a major goal of modern astrophysics. An interesting method for estimating these parameters is strong gravitational lensing of quasars (QSOs). As shown...... by Refsdal (1964), H0, !m and !! can be measured based on the time delay ("t) between multiply lensed images of QSOs, because "t depends on H0 and on the distances to lens and source, hence!m and !!. Determination of cosmological parameters using gravitational lensing suffers from some degeneracies......, but it is based on well understood physics and unlike distance ladder methods there are no calibration issues. Moreover, it has an advantage over some of the leading methods (such as Type Ia SNe) in that it is a purely cosmological approach. In this thesis, the property of strong gravitational lensing - time...

  6. Gallstone ileus resulting in strong intestinal obstruction

    Directory of Open Access Journals (Sweden)

    Israel Szajnbok

    Full Text Available Mechanic intestinal obstruction, caused by the passage of biliary calculus from vesicle to intestine, through fistulization, although not frequent, deserve study due to the morbi-mortality rates. Incidence in elder people explains the association with chronic degenerative diseases, increasing complexity in terms of therapy decision. Literature discusses the need and opportunity for the one or two-phase surgical attack of the cholecystenteric fistule, in front of the resolution on the obstructive urgency and makes reference to Gallstone Ileus as an exception for strong intestinal obstruction. The more frequent intestinal obstruction observed is when it occurs a Gallstone Ileus impacting in terms of ileocecal valve. The authors submit a Gallstone Ileus manifestation as causing strong intestinal obstruction, discussing aspects regarding diagnostic and treatment.

  7. Strong gauge boson scattering at the LHC

    CERN Document Server

    Rindani, S.D.

    2009-01-01

    In the standard model with electroweak symmetry breaking through the Higgs mechanism, electroweak gauge-boson scattering amplitudes are large if the Higgs boson is heavy, and electroweak gauge interactions become strong. In theories with electroweak symmetry breaking through alternative mechanisms, there could be a strongly interacting gauge sector, possibly with resonances in an accessible energy region. In general, the scattering of longitudinally polarized massive gauge bosons can give information on the mechanism of spontaneous symmetry breaking. At energies below the symmetry breaking scale, the equivalence theorem relates the scattering amplitudes to those of the "would-be" Goldstone modes. In the absence of Higgs bosons, unitarity would be restored by some new physics which can be studied through WW scattering. Some representatives models are discussed. Isolating WW scattering at a hadron collider from other contributions involving W emission from parton lines needs a good understanding of the backgrou...

  8. Strong spin-photon coupling in silicon.

    Science.gov (United States)

    Samkharadze, N; Zheng, G; Kalhor, N; Brousse, D; Sammak, A; Mendes, U C; Blais, A; Scappucci, G; Vandersypen, L M K

    2018-03-09

    Long coherence times of single spins in silicon quantum dots make these systems highly attractive for quantum computation, but how to scale up spin qubit systems remains an open question. As a first step to address this issue, we demonstrate the strong coupling of a single electron spin and a single microwave photon. The electron spin is trapped in a silicon double quantum dot, and the microwave photon is stored in an on-chip high-impedance superconducting resonator. The electric field component of the cavity photon couples directly to the charge dipole of the electron in the double dot, and indirectly to the electron spin, through a strong local magnetic field gradient from a nearby micromagnet. Our results provide a route to realizing large networks of quantum dot-based spin qubit registers. Copyright © 2018 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

  9. Cosmogenic photons strongly constrain UHECR source models

    Directory of Open Access Journals (Sweden)

    van Vliet Arjen

    2017-01-01

    Full Text Available 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.

  10. Waves in strong centrifugal fields: dissipationless gas

    Science.gov (United States)

    Bogovalov, S. V.; Kislov, V. A.; Tronin, I. V.

    2015-04-01

    Linear waves are investigated in a rotating gas under the condition of strong centrifugal acceleration of the order 106 g realized in gas centrifuges for separation of uranium isotopes. Sound waves split into three families of the waves under these conditions. Dispersion equations are obtained. The characteristics of the waves strongly differ from the conventional sound waves on polarization, velocity of propagation and distribution of energy of the waves in space for two families having frequencies above and below the frequency of the conventional sound waves. The energy of these waves is localized in rarefied region of the gas. The waves of the third family were not specified before. They propagate exactly along the rotational axis with the conventional sound velocity. These waves are polarized only along the rotational axis. Radial and azimuthal motions are not excited. Energy of the waves is concentrated near the wall of the rotor where the density of the gas is largest.

  11. Quantum strongly secure ramp secret sharing

    DEFF Research Database (Denmark)

    Zhang, Paul; Matsumoto, Rytaro Yamashita

    2015-01-01

    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...

  12. Hydrogen atoms in a strong magnetic field

    International Nuclear Information System (INIS)

    Santos, R.R. dos.

    1975-07-01

    The energies and wave functions of the 14 lowest states of a Hydrogen atom in a strong magnetic field are calculated, using a variational scheme. The equivalence between the atomic problem and the problems related with excitons and impurities in semiconductors in the presence of a strong magnetic field are shown. The calculations of the energies and wave functions have been divided in two regions: the first, for the magnetic field ranging between zero and 10 9 G; in the second the magnetic field ranges between 10 9 and 10 11 G. The results have been compared with those obtained by previous authors. The computation time necessary for the calculations is small. Therefore this is a convenient scheme to obtain the energies and wave functions for the problem. Transition probabilities, wavelengths and oscillator strengths for some allowed transitions are also calculated. (Author) [pt

  13. Electroweak and Strong Interactions Phenomenology, Concepts, Models

    CERN Document Server

    Scheck, Florian

    2012-01-01

    Electroweak and Strong Interaction: Phenomenology, Concepts, Models, begins with relativistic quantum mechanics and some quantum field theory which lay the foundation for the rest of the text. The phenomenology and the physics of the fundamental interactions are emphasized through a detailed discussion of the empirical fundamentals of unified theories of strong, electromagnetic, and weak interactions. The principles of local gauge theories are described both in a heuristic and a geometric framework. The minimal standard model of the fundamental interactions is developed in detail and characteristic applications are worked out. Possible signals of physics beyond that model, notably in the physics of neutrinos are also discussed. Among the applications scattering on nucleons and on nuclei provide salient examples. Numerous exercises with solutions make the text suitable for advanced courses or individual study. This completely updated revised new edition contains an enlarged chapter on quantum chromodynamics an...

  14. Frictional Coulomb drag in strong magnetic fields

    DEFF Research Database (Denmark)

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

    1997-01-01

    A treatment of frictional Coulomb drag between two two-dimensional electron layers in a strong perpendicular magnetic field, within the independent electron picture, is presented. Assuming fully resolved Landau levels, the linear response theory expression for the transresistivity rho(21) is eval......A treatment of frictional Coulomb drag between two two-dimensional electron layers in a strong perpendicular magnetic field, within the independent electron picture, is presented. Assuming fully resolved Landau levels, the linear response theory expression for the transresistivity rho(21......) is evaluated using diagrammatic techniques. The transresistivity is given by an integral over energy and momentum transfer weighted by the product of the screened interlayer interaction and the phase space for scattering events. We demonstrate, by a numerical analysis of the transresistivity, that for well...

  15. Orbits in weak and strong bars

    CERN Document Server

    Contopoulos, George

    1980-01-01

    The authors study the plane orbits in simple bar models embedded in an axisymmetric background when the bar density is about 1% (weak), 10% (intermediate) or 100% (strong bar) of the axisymmetric density. Most orbits follow the stable periodic orbits. The basic families of periodic orbits are described. In weak bars with two Inner Lindblad Resonances there is a family of stable orbits extending from the center up to the Outer Lindblad Resonance. This family contains the long period orbits near corotation. Other stable families appear between the Inner Lindblad Resonances, outside the Outer Lindblad Resonance, around corotation (short period orbits) and around the center (retrograde). Some families become unstable or disappear in strong bars. A comparison is made with cases having one or no Inner Lindblad Resonance. (12 refs).

  16. Strong sum distance in fuzzy graphs.

    Science.gov (United States)

    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.

  17. Analytical solution of strongly nonlinear Duffing oscillators

    Directory of Open Access Journals (Sweden)

    A.M. El-Naggar

    2016-06-01

    Full Text Available In this paper, a new perturbation technique is employed to solve strongly nonlinear Duffing oscillators, in which a new parameter α=α(ε is defined such that the value of α is always small regardless of the magnitude of the original parameter ε. Therefore, the strongly nonlinear Duffing oscillators with large parameter ε are transformed into a small parameter system with respect to α. Approximate solution obtained by the present method is compared with the solution of energy balance method, homotopy perturbation method, global error minimization method and lastly numerical solution. We observe from the results that this method is very simple, easy to apply, and gives a very good accuracy not only for small parameter εbut also for large values of ε.

  18. Strong interaction studies with kaonic atoms

    Directory of Open Access Journals (Sweden)

    Marton J.

    2016-01-01

    Full Text Available The strong interaction of antikaons (K− with nucleons and nuclei in the low-energy regime represents an active research field connected intrinsically with few-body physics. There are important open questions like the question of antikaon nuclear bound states - the prototype system being K−pp. A unique and rather direct experimental access to the antikaon-nucleon scattering lengths is provided by precision X-ray spectroscopy of transitions in low-lying states of light kaonic atoms like kaonic hydrogen isotopes. In the SIDDHARTA experiment at the electron-positron collider DAΦNE of LNF-INFN we measured the most precise values of the strong interaction observables, i.e. the strong interaction on the 1s ground state of the electromagnetically bound K−p atom leading to a hadronic shift ϵ1s and a hadronic broadening Γ1s of the 1s state. The SIDDHARTA result triggered new theoretical work which achieved major progress in the understanding of the low-energy strong interaction with strangeness. Antikaon-nucleon scattering lengths have been calculated constrained by the SIDDHARTA data on kaonic hydrogen. For the extraction of the isospin-dependent scattering lengths a measurement of the hadronic shift and width of kaonic deuterium is necessary. Therefore, new X-ray studies with the focus on kaonic deuterium are in preparation (SIDDHARTA2. Many improvements in the experimental setup will allow to measure kaonic deuterium which is challenging due to the anticipated low X-ray yield. Especially important are the data on the X-ray yields of kaonic deuterium extracted from a exploratory experiment within SIDDHARTA.

  19. SUSY strong production (leptonic) with ATLAS

    CERN Document Server

    Saito, Tomoyuki; The ATLAS collaboration

    2017-01-01

    Supersymmetry is one of the most motivated scenarios for physics beyond the Standard Model. This article summarizes recent ATLAS results on searches for supersymmetry in proton-proton collisions at a centre-of-mass energy of 13 TeV at LHC, which target supersymmetric particles produced by strong interaction in events with leptonic fi nal states. No signi ficant excess above the Standard Model expectation is observed and exclusion limits have been set on squark and gluino masses in various scenarios.

  20. Strong coupling QED with two fermionic flavors

    Energy Technology Data Exchange (ETDEWEB)

    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.

  1. Magnetic properties of strongly asymmetric nuclear matter

    International Nuclear Information System (INIS)

    Kutschera, M.; Wojcik, W.

    1988-01-01

    We investigate stability of neutron matter containing a small proton admixture with respect to spin fluctuations. We establish conditions under which strongly asymmetric nuclear matter could acquire a permanent magnetization. It is shown that if the protons are localized, the system becomes unstable to spin fluctuations for arbitrarily weak proton-neutron spin interactions. For non-localized protons there exists a threshold value of the spin interaction above which the system can develop a spontaneous polarization. 12 refs., 2 figs. (author)

  2. Strong coupling analogue of the Born series

    International Nuclear Information System (INIS)

    Dolinszky, T.

    1989-10-01

    In a given partial wave, the strength of the centrifugal term to be incorporated into the WKBA solutions in different spatial regions can be adjusted so as to make the first order wave functions everywhere smooth and, in strong coupling, exactly reproduce Quantum Mechanics throughout the space. The relevant higher order approximations supply an absolute convergent series expansion of the exact scattering state. (author) 4 refs.; 2 figs.; 2 tabs

  3. Strong-Q-sequences and small d

    Czech Academy of Sciences Publication Activity Database

    Chodounský, David

    2012-01-01

    Roč. 159, č. 3 (2012), s. 2942-2946 ISSN 0166-8641. [Prague Symposium on General Topology and its Relations to Modern Analysis and Algebra /11./. Prague, 07.08.2011-12.08.2011] Institutional support: RVO:67985840 Keywords : Katowice problem * strong-Q-sequence * dominating number Subject RIV: BA - General Mathematics Impact factor: 0.562, year: 2012 http://www.sciencedirect.com/science/article/pii/S0166864112002222

  4. Superbainite. A novel very strong bainitic microstructure

    International Nuclear Information System (INIS)

    Garcia-Mateo, C.; Caballero, E. G.; Bhadeshia, H. K. D. H.

    2005-01-01

    In this work very recent results are how that reveals the possibility of obtaining bainite by isothermal transformation at very low temperatures, of about 150 degree centigree, in high carbon high silicon steels. The microstructure thus obtained is a mixture of fine plates of bainite ferrite (20-40 nm thickness) and thin films of carbon enriched austenite. These microstructures are very hard (600 HV) and strong (2.5 GPa). (Author) 18 refs

  5. Strong decays of nonstrange q3 baryons

    International Nuclear Information System (INIS)

    Bijker, R.; Iachello, F.; Leviatan, A.

    1997-01-01

    We study strong decays of nonstrange baryons by making use of the algebraic approach to hadron structure. Within this framework we derive closed expressions for decay widths in an elementary-meson emission model and use these to analyze the experimental data for N * →N+π, N * →Δ+π, N * →N+η, Δ * →N+π, Δ * →Δ+π, and Δ * →Δ+η decays. copyright 1997 The American Physical Society

  6. Transport phenomena in environmental engineering

    Science.gov (United States)

    Sander, Aleksandra; Kardum, Jasna Prlić; Matijašić, Gordana; Žižek, Krunoslav

    2018-01-01

    A term transport phenomena arises as a second paradigm at the end of 1950s with high awareness that there was a strong need to improve the scoping of chemical engineering science. At that point, engineers became highly aware that it is extremely important to take step forward from pure empirical description and the concept of unit operations only to understand the specific process using phenomenological equations that rely on three elementary physical processes: momentum, energy and mass transport. This conceptual evolution of chemical engineering was first presented with a well-known book of R. Byron Bird, Warren E. Stewart and Edwin N. Lightfoot, Transport Phenomena, published in 1960 [1]. What transport phenomena are included in environmental engineering? It is hard to divide those phenomena through different engineering disciplines. The core is the same but the focus changes. Intention of the authors here is to present the transport phenomena that are omnipresent in treatment of various process streams. The focus in this chapter is made on the transport phenomena that permanently occur in mechanical macroprocesses of sedimentation and filtration for separation in solid-liquid particulate systems and on the phenomena of the flow through a fixed and a fluidized bed of particles that are immanent in separation processes in packed columns and in environmental catalysis. The fundamental phenomena for each thermal and equilibrium separation process technology are presented as well. Understanding and mathematical description of underlying transport phenomena result in scoping the separation processes in a way that ChEs should act worldwide.

  7. Thermalhydraulics and activity transport

    International Nuclear Information System (INIS)

    McDonald, B.H.; Wren, D.J.

    1990-01-01

    The potential consequences of a reactor accident, in terms of its impact on public safety, rest on the source term of radioactive fission products. The source term, as, as defined by an international group of experts, is the quantity of radioactive material which might be released in a nuclear accident: its physical and chemical form and the other quantities needed to completely specify its dispersion in the environment (e.g., energy in the plume, height of release, duration of release etc.). Although there are a large number of physical and chemical factors that will contribute to the determination of the source term for a given accident scenario, those factors having a direct impact on the rate of transport are of obvious importance. The thermalhydraulic conditions controlling the rate of mass transport, among other things, are probably the most important factors influencing the source term. This paper is an overview of the areas in which thermalhydraulics most strongly influences activity transport during a severe accident in a water-cooled reactor. It also includes some discussion of the areas where coupling between the physics used in separate computer models of the two phenomena must be considered in any mechanistic best-estimate calculations of the source term

  8. Nanoscale thermal transport

    Science.gov (United States)

    Cahill, David G.; Ford, Wayne K.; Goodson, Kenneth E.; Mahan, Gerald D.; Majumdar, Arun; Maris, Humphrey J.; Merlin, Roberto; Phillpot, Simon R.

    2003-01-01

    Rapid progress in the synthesis and processing of materials with structure on nanometer length scales has created a demand for greater scientific understanding of thermal transport in nanoscale devices, individual nanostructures, and nanostructured materials. This review emphasizes developments in experiment, theory, and computation that have occurred in the past ten years and summarizes the present status of the field. Interfaces between materials become increasingly important on small length scales. The thermal conductance of many solid-solid interfaces have been studied experimentally but the range of observed interface properties is much smaller than predicted by simple theory. Classical molecular dynamics simulations are emerging as a powerful tool for calculations of thermal conductance and phonon scattering, and may provide for a lively interplay of experiment and theory in the near term. Fundamental issues remain concerning the correct definitions of temperature in nonequilibrium nanoscale systems. Modern Si microelectronics are now firmly in the nanoscale regime—experiments have demonstrated that the close proximity of interfaces and the extremely small volume of heat dissipation strongly modifies thermal transport, thereby aggravating problems of thermal management. Microelectronic devices are too large to yield to atomic-level simulation in the foreseeable future and, therefore, calculations of thermal transport must rely on solutions of the Boltzmann transport equation; microscopic phonon scattering rates needed for predictive models are, even for Si, poorly known. Low-dimensional nanostructures, such as carbon nanotubes, are predicted to have novel transport properties; the first quantitative experiments of the thermal conductivity of nanotubes have recently been achieved using microfabricated measurement systems. Nanoscale porosity decreases the permittivity of amorphous dielectrics but porosity also strongly decreases the thermal conductivity. The

  9. Simulation of turbulent flows containing strong shocks

    Science.gov (United States)

    Fryxell, Bruce; Menon, Suresh

    2008-12-01

    Simulation of turbulent flows with strong shocks is a computationally challenging problem. The requirements for a method to produce accurate results for turbulence are orthogonal to those needed to treat shocks properly. In order to prevent an unphysical rate of decay of turbulent structures, it is necessary to use a method with very low numerical dissipation. Because of this, central difference schemes are widely used. However, computing strong shocks with a central difference scheme can produce unphysical post-shock oscillations that corrupt the entire flow unless additional dissipation is added. This dissipation can be difficult to localize to the area near the shock and can lead to inaccurate treatment of the turbulence. Modern high-resolution shock-capturing methods usually use upwind algorithms to provide the dissipation necessary to stabilize shocks. However, this upwind dissipation can also lead to an unphysical rate of decay of the turbulence. This paper discusses a hybrid method for simulating turbulent flows with strong shocks that couples a high-order central difference scheme with a high-resolution shock-capturing method. The shock-capturing method is used only in the vicinity of discontinuities in the flow, whereas the central difference scheme is used in the remainder of the computational domain. Results of this new method will be shown for a variety of test problems. Preliminary results for a realistic application involving detonation in gas-particle flows will also be presented.

  10. Strong CP, flavor, and twisted split fermions

    International Nuclear Information System (INIS)

    Harnik, Roni; Perez, Gilad; Schwartz, Matthew D.; Shirman, Yuri

    2005-01-01

    We present a natural solution to the strong CP problem in the context of split fermions. By assuming CP is spontaneously broken in the bulk, a weak CKM phase is created in the standard model due to a twisting in flavor space of the bulk fermion wavefunctions. But the strong CP phase remains zero, being essentially protected by parity in the bulk and CP on the branes. As always in models of spontaneous CP breaking, radiative corrections to theta bar from the standard model are tiny, but even higher dimension operators are not that dangerous. The twisting phenomenon was recently shown to be generic, and not to interfere with the way that split fermions naturally weaves small numbers into the standard model. It follows that out approach to strong CP is compatible with flavor, and we sketch a comprehensive model. We also look at deconstructed version of this setup which provides a viable 4D model of spontaneous CP breaking which is not in the Nelson-Barr class. (author)

  11. Simulation of turbulent flows containing strong shocks

    International Nuclear Information System (INIS)

    Fryxell, Bruce; Menon, Suresh

    2008-01-01

    Simulation of turbulent flows with strong shocks is a computationally challenging problem. The requirements for a method to produce accurate results for turbulence are orthogonal to those needed to treat shocks properly. In order to prevent an unphysical rate of decay of turbulent structures, it is necessary to use a method with very low numerical dissipation. Because of this, central difference schemes are widely used. However, computing strong shocks with a central difference scheme can produce unphysical post-shock oscillations that corrupt the entire flow unless additional dissipation is added. This dissipation can be difficult to localize to the area near the shock and can lead to inaccurate treatment of the turbulence. Modern high-resolution shock-capturing methods usually use upwind algorithms to provide the dissipation necessary to stabilize shocks. However, this upwind dissipation can also lead to an unphysical rate of decay of the turbulence. This paper discusses a hybrid method for simulating turbulent flows with strong shocks that couples a high-order central difference scheme with a high-resolution shock-capturing method. The shock-capturing method is used only in the vicinity of discontinuities in the flow, whereas the central difference scheme is used in the remainder of the computational domain. Results of this new method will be shown for a variety of test problems. Preliminary results for a realistic application involving detonation in gas-particle flows will also be presented.

  12. Transporter Classification Database (TCDB)

    Data.gov (United States)

    U.S. Department of Health & Human Services — The Transporter Classification Database details a comprehensive classification system for membrane transport proteins known as the Transporter Classification (TC)...

  13. The INGV Real Time Strong Motion Database

    Science.gov (United States)

    Massa, Marco; D'Alema, Ezio; Mascandola, Claudia; Lovati, Sara; Scafidi, Davide; Gomez, Antonio; Carannante, Simona; Franceschina, Gianlorenzo; Mirenna, Santi; Augliera, Paolo

    2017-04-01

    The INGV real time strong motion data sharing is assured by the INGV Strong Motion Database. ISMD (http://ismd.mi.ingv.it) was designed in the last months of 2011 in cooperation among different INGV departments, with the aim to organize the distribution of the INGV strong-motion data using standard procedures for data acquisition and processing. The first version of the web portal was published soon after the occurrence of the 2012 Emilia (Northern Italy), Mw 6.1, seismic sequence. At that time ISMD was the first European real time web portal devoted to the engineering seismology community. After four years of successfully operation, the thousands of accelerometric waveforms collected in the archive need necessary a technological improvement of the system in order to better organize the new data archiving and to make more efficient the answer to the user requests. ISMD 2.0 was based on PostgreSQL (www.postgresql.org), an open source object- relational database. The main purpose of the web portal is to distribute few minutes after the origin time the accelerometric waveforms and related metadata of the Italian earthquakes with ML≥3.0. Data are provided both in raw SAC (counts) and automatically corrected ASCII (gal) formats. The web portal also provide, for each event, a detailed description of the ground motion parameters (i.e. Peak Ground Acceleration, Velocity and Displacement, Arias and Housner Intensities) data converted in velocity and displacement, response spectra up to 10.0 s and general maps concerning the recent and the historical seismicity of the area together with information about its seismic hazard. The focal parameters of the events are provided by the INGV National Earthquake Center (CNT, http://cnt.rm.ingv.it). Moreover, the database provides a detailed site characterization section for each strong motion station, based on geological, geomorphological and geophysical information. At present (i.e. January 2017), ISMD includes 987 (121

  14. The Electron-Phonon Interaction in Strongly Correlated Systems

    International Nuclear Information System (INIS)

    Castellani, C.; Grilli, M.

    1995-01-01

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

  15. Negative mobility of a Brownian particle: Strong damping regime

    Science.gov (United States)

    Słapik, A.; Łuczka, J.; Spiechowicz, J.

    2018-02-01

    We study impact of inertia on directed transport of a Brownian particle under non-equilibrium conditions: the particle moves in a one-dimensional periodic and symmetric potential, is driven by both an unbiased time-periodic force and a constant force, and is coupled to a thermostat of temperature T. Within selected parameter regimes this system exhibits negative mobility, which means that the particle moves in the direction opposite to the direction of the constant force. It is known that in such a setup the inertial term is essential for the emergence of negative mobility and it cannot be detected in the limiting case of overdamped dynamics. We analyse inertial effects and show that negative mobility can be observed even in the strong damping regime. We determine the optimal dimensionless mass for the presence of negative mobility and reveal three mechanisms standing behind this anomaly: deterministic chaotic, thermal noise induced and deterministic non-chaotic. The last origin has never been reported. It may provide guidance to the possibility of observation of negative mobility for strongly damped dynamics which is of fundamental importance from the point of view of biological systems, all of which in situ operate in fluctuating environments.

  16. Strong Localization in Disordered Media: Analysis of the Backscattering Cone

    KAUST Repository

    Delgado, Edgar

    2012-06-01

    A very interesting effect in light propagation through a disordered system is Anderson localization of light, this phenomenon emerges as the result of multiple scattering of waves by electric inhomogeneities like spatial variations of index of refraction; as the amount of scattering is increased, light propagation is converted from quasi-diffusive to exponentially localized, with photons confined in a limited spatial region characterized by a fundamental quantity known as localization length. Light localization is strongly related to another interference phenomenon emerged from the multiple scattering effect: the coherent backscattering effect. In multiple scattering of waves, in fact, coherence is preserved in the backscattering direction and produces a reinforcement of the field flux originating an observable peak in the backscattered intensity, known as backscattering cone. The study of this peak provide quantitative information about the transport properties of light in the material. In this thesis we report a complete FDTD ab-initio study of light localization and coherent backscattering. In particular, we consider a supercontinuum pulse impinging on a sample composed of randomly positioned scatterers. We study coherent backscattering by averaging over several realizations of the sample properties. We study then the coherent backscattering cone properties as the relative permittivity of the sample is changed, relating the latter with the light localization inside the sample. We demonstrate important relationships between the width of the backscattering cone and the localization length, which shows a linear proportionality in the strong localization regime.

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

    Science.gov (United States)

    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…

  18. 77 FR 16131 - Establishing a White House Council on Strong Cities, Strong Communities

    Science.gov (United States)

    2012-03-20

    ... Order 13602 of March 15, 2012 Establishing a White House Council on Strong Cities, Strong Communities By... enable them to develop and implement economic strategies to become more competitive, sustainable, and inclusive, it is hereby ordered as follows: Section 1. Policy. Cities, towns, and regions across our Nation...

  19. Disorder effects in strongly correlated uranium compounds

    International Nuclear Information System (INIS)

    Suellow, S.; Maple, M.B.; Tomuta, D.; Nieuwenhuys, G.J.; Menovsky, A.A.; Mydosh, J.A.; Chau, R.

    2001-01-01

    Moderate levels of crystallographic disorder can dramatically affect the ground-state properties of heavy fermion compounds. In particular, the role of disorder close to a quantum critical point has been investigated in detail. However, crystallographic disorder is equally effective in altering the properties of magnetically ordered heavy fermion compounds like URh 2 Ge 2 , where disorder-induced spin-glass behavior has been observed. In this system, moreover, the magnetic ground state can be tuned from a spin-glass to a long-range ordered antiferromagnetic one by means of an annealing treatment. The transformation of the magnetic state is accompanied by a transition in the transport properties from 'quasi-insulating' (dρ/dT 2 Ge 2 will be discussed. Of particular interest is the resistivity of as-grown URh 2 Ge 2 , which resembles the Non-Fermi-liquid system UCu 4 Pd, suggesting that a common mechanism - the crystallographic disorder - controls the transport properties of these materials

  20. Supporting aboriginal knowledge and practice in health care: lessons from a qualitative evaluation of the strong women, strong babies, strong culture program.

    Science.gov (United States)

    Lowell, Anne; Kildea, Sue; Liddle, Marlene; Cox, Barbara; Paterson, Barbara

    2015-02-05

    The Strong Women, Strong Babies, Strong Culture Program (the Program) evolved from a recognition of the value of Aboriginal knowledge and practice in promoting maternal and child health (MCH) in remote communities of the Northern Territory (NT) of Australia. Commencing in 1993 it continues to operate today. In 2008, the NT Department of Health commissioned an evaluation to identify enabling factors and barriers to successful implementation of the Program, and to identify potential pathways for future development. In this paper we focus on the evaluation findings related specifically to the role of Aborignal cultural knowledge and practice within the Program. A qualitative evaluation utilised purposive sampling to maximise diversity in program history and Aboriginal culture. Semi-structured, in-depth interviews with 76 participants were recorded in their preferred language with a registered Interpreter when required. Thematic analysis of data was verified or modified through further discussions with participants and members of the evaluation team. Although the importance of Aboriginal knowledge and practice as a fundamental component of the Program is widely acknowledged, there has been considerable variation across time and location in the extent to which these cultural dimensions have been included in practice. Factors contributing to this variation are complex and relate to a number of broad themes including: location of control over Program activities; recognition and respect for Aboriginal knowledge and practice as a legitimate component of health care; working in partnership; communication within and beyond the Program; access to transport and working space; and governance and organisational support. We suggest that inclusion of Aboriginal knowledge and practice as a fundamental component of the Program is key to its survival over more than twenty years despite serious challenges. Respect for the legitimacy of Aboriginal knowledge and practice within health

  1. Transport Phenomena in Gel

    Directory of Open Access Journals (Sweden)

    Masayuki Tokita

    2016-05-01

    Full Text Available Gel becomes an important class of soft materials since it can be seen in a wide variety of the chemical and the biological systems. The unique properties of gel arise from the structure, namely, the three-dimensional polymer network that is swollen by a huge amount of solvent. Despite the small volume fraction of the polymer network, which is usually only a few percent or less, gel shows the typical properties that belong to solids such as the elasticity. Gel is, therefore, regarded as a dilute solid because its elasticity is much smaller than that of typical solids. Because of the diluted structure, small molecules can pass along the open space of the polymer network. In addition to the viscous resistance of gel fluid, however, the substance experiences resistance due to the polymer network of gel during the transport process. It is, therefore, of importance to study the diffusion of the small molecules in gel as well as the flow of gel fluid itself through the polymer network of gel. It may be natural to assume that the effects of the resistance due to the polymer network of gel depends strongly on the network structure. Therefore, detailed study on the transport processes in and through gel may open a new insight into the relationship between the structure and the transport properties of gel. The two typical transport processes in and through gel, that is, the diffusion of small molecules due to the thermal fluctuations and the flow of gel fluid that is caused by the mechanical pressure gradient will be reviewed.

  2. Primary and secondary thyroid hormone transporters

    Directory of Open Access Journals (Sweden)

    Kinne Anita

    2011-08-01

    Full Text Available Abstract Thyroid hormones (TH are essential for the development of the human brain, growth and cellular metabolism. Investigation of TH transporters became one of the emerging fields in thyroid research after the discovery of inactivating mutations in the Monocarboxylate transporter 8 (MCT8, which was found to be highly specific for TH transport. However, additional transmembrane transporters are also very important for TH uptake and efflux in different cell types. They transport TH as secondary substrates and include the aromatic amino acid transporting MCT10, the organic anion transporting polypeptides (e.g. OATP1C1, OATP1A2, OPTP1A4 and the large neutral amino acid transporters (LAT1 and LAT2. These TH transporters characteristically possess 12 transmembrane spanners but due to the strong differing sequences between the three transporter families we assume an identical conformation is not very likely. In contrast to the others, the LAT family members form a heterodimer with the escort protein 4F2hc/CD98. A comparison of sequence proportions, locations and types of functional sensitive features for TH transport discovered by mutations, revealed that transport sensitive charged residues occur as conserved amino acids only within each family of the transporter types but not in all putative TH transporters. Based on the lack of highly conserved sensitive charged residues throughout the three transporter families as a common counterpart for the amino acid moiety of the substrates, we conclude that the molecular transport mechanism is likely organized either a by different molecular determinants in the divergent transporter types or b the counterparts for the substrates` amino acid moiety at the transporter are not any charged side chains but other proton acceptors or donators. However, positions of transport sensitive residues coincide at transmembrane helix 8 in the TH transporter MCT8, OATP1C1 and another amino acid transporter, the L

  3. Renormalization in theories with strong vector forces

    International Nuclear Information System (INIS)

    Kocic, A.

    1991-01-01

    There are not many field theories in four dimensions that have sensible ultraviolet and interesting (non-trivial) infrared behavior. At present, asymptotically free theories seem to have deserved their legitimacy and there is a strong prejudice that they might be the only ones to have such a distinction. This belief stems mostly from the fact that most of the knowledge of field theory in four dimensions comes from perturbation theory. However, nonperturbative studies of the lower dimensional theories reveal a host of interesting phenomena that are perturbative studies of the lower dimensional theories reveal a host of interesting phenomena that perturbatively inaccessible. The lack of asymptotic freedom implies that the coupling constant grows at short distances and perturbation theory breaks down. Thus, in such theories, ultraviolet behavior requires nonperturbative treatment. Recently, the interest in strongly coupled gauge theories has been revived. In particularly, four dimensional quantum electrodynamics has received considerable attention. This was motivated by the discovery of an ultraviolet stable fixed point at strong couplings. If this fixed point would turn out to be non-gaussian, then QED would be the first nontrivial nonasymptotically free theory in four dimensions. The importance of such a result would be twofold. First, the old question of the existence of QED could be settled. Of course, this would be the case provided that the low energy limit of the theory actually describes photons and electrons; apriori, there is no reason to assume this. Second, the discovery of a nontrivial nonasymptotically free theory would be of great paradigmatic value. The theories which quenched QED resembles the most are nonabelian gauge theories with many flavors with beta-function positive or vanishing at weak couplings. These theories are at present considered as viable candidates for technicolor unification schemes

  4. Proton Transport

    Science.gov (United States)

    Pohorille, Andrew; DeVincenzi, Donald L. (Technical Monitor)

    2001-01-01

    The transport of protons across membranes is an essential process for both bioenergetics of modern cells and the origins of cellular life. All living systems make use of proton gradients across cell walls to convert environmental energy into a high-energy chemical compound, adenosine triphosphate (ATP), synthesized from adenosine diphosphate. ATP, in turn, is used as a source of energy to drive many cellular reactions. The ubiquity of this process in biology suggests that even the earliest cellular systems were relying on proton gradient for harvesting environmental energy needed to support their survival and growth. In contemporary cells, proton transfer is assisted by large, complex proteins embedded in membranes. The issue addressed in this Study was: how the same process can be accomplished with the aid of similar but much simpler molecules that could have existed in the protobiological milieu? The model system used in the study contained a bilayer membrane made of phospholipid, dimyristoylphosphatidylcholine (DMPC) which is a good model of the biological membranes forming cellular boundaries. Both sides of the bilayer were surrounded by water which simulated the environment inside and outside the cell. Embedded in the membrane was a fragment of the Influenza-A M$_2$ protein and enough sodium counterions to maintain system neutrality. This protein has been shown to exhibit remarkably high rates of proton transport and, therefore, is an excellent model to study the formation of proton gradients across membranes. The Influenza M$_2$ protein is 97 amino acids in length, but a fragment 25 amino acids long. which contains a transmembrane domain of 19 amino acids flanked by three amino acids on each side. is sufficient to transport protons. Four identical protein fragments, each folded into a helix, aggregate to form small channels spanning the membrane. Protons are conducted through a narrow pore in the middle of the channel in response to applied voltage. This

  5. Bound states in a strong magnetic field

    International Nuclear Information System (INIS)

    Machado, C. S.; Navarra, F. S.; Noronha, J.; Oliveira, E. G.; Ferreira Filho, L. G.

    2013-01-01

    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∼m 2 π ∼ 0.02 GeV 2 at the RHIC and eB∼ 15m 2 π ∼ 0.3 GeV 2 at the LHC. We investigate the effects of the magnetic field on B 0 and D 0 mesons, focusing on the changes of the energy levels and of the mass of the bound states.

  6. Strong signatures of right-handed compositeness

    Energy Technology Data Exchange (ETDEWEB)

    Redi, Michele [INFN, Sesto Fiorentino, Firenze (Italy); Sanz, Veronica [York Univ., Toronto, ON (Canada). Dept. of Physics and Astronomy; Sussex Univ., Brighton (United Kingdom). Dept. of Physics and Astronomy; Vries, Maikel de; Weiler, Andreas [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

    2013-05-15

    Right-handed light quarks could be significantly composite, yet compatible with experimental searches at the LHC and precision tests on Standard Model couplings. In these scenarios, that are motivated by flavor physics, one expects large cross sections for the production of new resonances coupled to light quarks. We study experimental strong signatures of right-handed compositeness at the LHC, and constrain the parameter space of these models with recent results by ATLAS and CMS. We show that the LHC sensitivity could be significantly improved if dedicated searches were performed, in particular in multi-jet signals.

  7. The Dark Side of Strongly Coupled Theories

    DEFF Research Database (Denmark)

    Kouvaris, Christoforos

    2008-01-01

    We investigate the constraints of dark matter search experiments on the different candidates emerging from the minimal quasi-conformal strong coupling theory with fermions in the adjoint representation. For one candidate, the current limits of CDMS exclude a tiny window of masses around 120 GeV. We...... also investigate under what circumstances the newly proposed candidate composed of a -2 negatively charged particle and a $^4He^{+2}$ can explain the discrepancy between the results of the CDMS and DAMA experiments. We found that this type of dark matter should give negative results in CDMS, while...

  8. Fundamental Structure of Matter and Strong Interaction

    Energy Technology Data Exchange (ETDEWEB)

    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.

  9. Strong Interaction Studies with PANDA at FAIR

    International Nuclear Information System (INIS)

    Schönning, Karin

    2016-01-01

    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

  10. Hawking radiation and strong gravity black holes

    International Nuclear Information System (INIS)

    Qadir, A.; Sayed, W.A.

    1979-01-01

    It is shown that the strong gravity theory of Salam et al. places severe restrictions on black hole evaporation. Two major implications are that: mini blck holes (down to masses approximately 10 -16 kg) would be stable in the present epoch; and that some suggested mini black hole mechanisms to explain astrophysical phenomena would not work. The first result implies that f-gravity appears to make black holes much safer by removing the possibility of extremely violent black hole explosions suggested by Hawking. (Auth.)

  11. Wormhole effect in a strong topological insulator

    Science.gov (United States)

    Rosenberg, G.; Guo, H.-M.; Franz, M.

    2010-07-01

    An infinitely thin solenoid carrying magnetic flux Φ (a “Dirac string”) inserted into an ordinary band insulator has no significant effect on the spectrum of electrons. In a strong topological insulator, remarkably, such a solenoid carries protected gapless one-dimensional fermionic modes when Φ=hc/2e . These modes are spin-filtered and represent a distinct bulk manifestation of the topologically nontrivial insulator. We establish this “wormhole” effect by both general qualitative considerations and by numerical calculations within a minimal lattice model. We also discuss the possibility of experimental observation of a closely related effect in artificially engineered nanostructures.

  12. Strong piezoelectricity in bioinspired peptide nanotubes.

    Science.gov (United States)

    Kholkin, Andrei; Amdursky, Nadav; Bdikin, Igor; Gazit, Ehud; Rosenman, Gil

    2010-02-23

    We show anomalously strong shear piezoelectric activity in self-assembled diphenylalanine peptide nanotubes (PNTs), indicating electric polarization directed along the tube axis. Comparison with well-known piezoelectric LiNbO(3) and lateral signal calibration yields sufficiently high effective piezoelectric coefficient values of at least 60 pm/V (shear response for tubes of approximately 200 nm in diameter). PNTs demonstrate linear deformation without irreversible degradation in a broad range of driving voltages. The results open up a wide avenue for developing new generations of "green" piezoelectric materials and piezonanodevices based on bioactive tubular nanostructures potentially compatible with human tissue.

  13. Development of a strong electromagnet wiggler

    International Nuclear Information System (INIS)

    Burns, M.J.; Deis, G.A.; Holmes, R.H.; Van Maren, R.D.; Halbach, K.

    1987-01-01

    The Strong Electromagnet (SEM) wiggler is a permanent magnet-assisted electromagnet under development at the Lawrence Livermore National Laboratory (LLNL) as part of the Induction Linac Free-Electron-Laser (IFEL) program. This concept uses permanent magnets within the wiggler to provide a reverse bias flux in the iron and thus delay the onset of magnetic saturation. The electromagnet coils determine the wiggler field and operate at low current densities by virtue of their placement away from the midplane. We describe here the design approach used and test data from a 7-period wiggler prototype that includes curved pole tips to provide wiggle-plane focusing. 7 refs

  14. Strong Interactions Physics at BaBar

    Energy Technology Data Exchange (ETDEWEB)

    Pioppi, M.

    2005-03-14

    Recent results obtained by BABAR experiment and related to strong interactions physics are presented, with particular attention to the extraction of the first four hadronic-mass moments and the first three lepton-energy moments in semileptonic decays. From a simultaneous fit to the moments, the CKM element |V{sub cb}|, the inclusive B {yields} X{sub c}lv and other heavy quark parameters are derived. The second topic is the ambiguity-free measurement of cos(2{beta}) in B {yields} J/{Psi}K* decays. With approximately 88 million of B{bar B} pairs, negative solutions for cos(2{beta}) are excluded at 89%.

  15. Phase diagram of strongly correlated Fermi systems

    International Nuclear Information System (INIS)

    Zverev, M.V.; Khodel', V.A.; Baldo, M.

    2000-01-01

    Phase transitions in uniform Fermi systems with repulsive forces between the particles caused by restructuring of quasiparticle filling n(p) are analyzed. It is found that in terms of variables, i.e. density ρ, nondimensional binding constant η, phase diagram of a strongly correlated Fermi system for rather a wide class of interactions reminds of a puff-pastry pie. Its upper part is filled with fermion condensate, the lower one - with normal Fermi-liquid. They are separated by a narrow interlayer - the Lifshits phase, characterized by the Fermi multibound surface [ru

  16. Quantum electrodynamics in strong external fields

    International Nuclear Information System (INIS)

    Mueller, B.; Rafelski, J.; Kirsch, J.

    1981-05-01

    We review the theoretical description of quantum electrodynamics in the presence of strong and supercritical fields. In particular, the process of the spontaneous vacuum decay accompanied by the observable positron emission in heavy ion collisions is described. Emphasis is put on the proper formulation of many-body aspects in the framework of quantum field theory. The extension of the theory to the description of Bose fields and many-body effects is presented, and the Klein paradox is resolved. Some implications of the theoretical methods developed here are presented concerning non-abelian gauge theories and the quark confinement puzzle. (orig.)

  17. Strong Interaction Studies with PANDA at FAIR

    Science.gov (United States)

    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.

  18. Particle and heat transport in Tokamaks

    International Nuclear Information System (INIS)

    Chatelier, M.

    1984-01-01

    A limitation to performances of tokamaks is heat transport through magnetic surfaces. Principles of ''classical'' or ''neoclassical'' transport -i.e. transport due to particle and heat fluxes due to Coulomb scattering of charged particle in a magnetic field- are exposed. It is shown that beside this classical effect, ''anomalous'' transport occurs; it is associated to the existence of fluctuating electric or magnetic fields which can appear in the plasma as a result of charge and current perturbations. Tearing modes and drift wave instabilities are taken as typical examples. Experimental features are presented which show that ions behave approximately in a classical way whereas electrons are strongly anomalous [fr

  19. research efforts on intelligent transportation system in nigeria

    African Journals Online (AJOL)

    The critical situation of unwelcome frustration experienced by urban trip makers and roadside dwellers alike, calls for a very strong push by all stakeholders in the transportation sector to enhance the service performance of transportation facilities using Intelligent Transportation Systems (ITS). Needed strategies for ...

  20. Perspectives for Sustainable Urban Transport Planning in Irkutsk

    Directory of Open Access Journals (Sweden)

    Barbara Engel

    2015-05-01

    Full Text Available Mobility is a strong demand of urban societies and transport systems are backbones of urban life – in Russian cities like in other cities all over the world. Transport planning has to be understood as an integral part of urban development and urban planning. The report discusses problems and chances for sustainable urban transport planning in Irkutsk.

  1. National transportation statistics 2011

    Science.gov (United States)

    2011-04-01

    Compiled and published by the U.S. Department of Transportation's Bureau of Transportation Statistics (BTS), National Transportation Statistics presents information on the U.S. transportation system, including its physical components, safety record, ...

  2. Electrostatic turbulence in strongly magnetized plasmas

    International Nuclear Information System (INIS)

    Nielsen, A.H.

    1993-01-01

    Turbulence in plasmas has been investigated experimentally and numerically. On the experimental side the turbulent nature of the Kelvin-Helmholtz instability has been studied in a single-ended Q-machine. The development of coherent structures in the background of the turbulent flow has been demonstrated and the capability of structures of transporting plasma across the magnetic field-lines is explained in detail. The numerical investigations are divided into two parts: Numerical simulations of the dynamics from the Q-machine experiments using spectral methods to solve the two-dimensional Navier-Stokes equations in a cylindrical geometry. A numerical study of the Eulerian-Lagrangian transformation in a two-dimensional flow. Here the flow is made up by a large number of structures, where each individual structure is convected by the superposed flow field of all the others. (au) (33 ills., 67 refs.)

  3. Iterative solutions of nonlinear equations with strongly accretive or strongly pseudocontractive maps

    International Nuclear Information System (INIS)

    Chidume, C.E.

    1994-03-01

    Let E be a real q-uniformly smooth Banach space. Suppose T is a strongly pseudo-contractive map with open domain D(T) in E. Suppose further that T has a fixed point in D(T). Under various continuity assumptions on T it is proved that each of the Mann iteration process or the Ishikawa iteration method converges strongly to the unique fixed point of T. Related results deal with iterative solutions of nonlinear operator equations involving strongly accretive maps. Explicit error estimates are also provided. (author). 38 refs

  4. Towards TDDFT for Strongly Correlated Materials

    Directory of Open Access Journals (Sweden)

    Shree Ram Acharya

    2016-09-01

    Full Text Available We present some details of our recently-proposed Time-Dependent Density-Functional Theory (TDDFT for strongly-correlated materials in which the exchange-correlation (XC kernel is derived from the charge susceptibility obtained using Dynamical Mean-Field Theory (the TDDFT + DMFT approach. We proceed with deriving the expression for the XC kernel for the one-band Hubbard model by solving DMFT equations via two approaches, the Hirsch–Fye Quantum Monte Carlo (HF-QMC and an approximate low-cost perturbation theory approach, and demonstrate that the latter gives results that are comparable to the exact HF-QMC solution. Furthermore, through a variety of applications, we propose a simple analytical formula for the XC kernel. Additionally, we use the exact and approximate kernels to examine the nonhomogeneous ultrafast response of two systems: a one-band Hubbard model and a Mott insulator YTiO3. We show that the frequency dependence of the kernel, i.e., memory effects, is important for dynamics at the femtosecond timescale. We also conclude that strong correlations lead to the presence of beats in the time-dependent electric conductivity in YTiO3, a feature that could be tested experimentally and that could help validate the few approximations used in our formulation. We conclude by proposing an algorithm for the generalization of the theory to non-linear response.

  5. The Athens Acropolis Strong Motion Array

    Science.gov (United States)

    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.

  6. Relativistically strong electromagnetic radiation in a plasma

    Science.gov (United States)

    Bulanov, S. V.; Esirkepov, T. Zh.; Kando, M.; Kiriyama, H.; Kondo, K.

    2016-03-01

    Physical processes in a plasma under the action of relativistically strong electromagnetic waves generated by high-power lasers have been briefly reviewed. These processes are of interest in view of the development of new methods for acceleration of charged particles, creation of sources of bright hard electromagnetic radiation, and investigation of macroscopic quantum-electrodynamical processes. Attention is focused on nonlinear waves in a laser plasma for the creation of compact electron accelerators. The acceleration of plasma bunches by the radiation pressure of light is the most efficient regime of ion acceleration. Coherent hard electromagnetic radiation in the relativistic plasma is generated in the form of higher harmonics and/or electromagnetic pulses, which are compressed and intensified after reflection from relativistic mirrors created by nonlinear waves. In the limit of extremely strong electromagnetic waves, radiation friction, which accompanies the conversion of radiation from the optical range to the gamma range, fundamentally changes the behavior of the plasma. This process is accompanied by the production of electron-positron pairs, which is described within quantum electrodynamics theory.

  7. Strong Double Higgs Production at the LHC

    CERN Document Server

    Contino, Roberto; Moretti, Mauro; Piccinini, Fulvio; Rattazzi, Riccardo

    2010-01-01

    The hierarchy problem and the electroweak data, together, provide a plausible motivation for considering a light Higgs emerging as a pseudo-Goldstone boson from a strongly-coupled sector. In that scenario, the rates for Higgs production and decay differ significantly from those in the Standard Model. However, one genuine strong coupling signature is the growth with energy of the scattering amplitudes among the Goldstone bosons, the longitudinally polarized vector bosons as well as the Higgs boson itself. The rate for double Higgs production in vector boson fusion is thus enhanced with respect to its negligible rate in the SM. We study that reaction in pp collisions, where the production of two Higgs bosons at high pT is associated with the emission of two forward jets. We concentrate on the decay mode hh -> WW^(*)WW^(*) and study the semi-leptonic decay chains of the W's with 2, 3 or 4 leptons in the final states. While the 3 lepton final states are the most relevant and can lead to a 3 sigma signal significa...

  8. Finite temperature system of strongly interacting baryons

    Energy Technology Data Exchange (ETDEWEB)

    Bowers, R.L.; Gleeson, A.M.; Pedigo, R.D.; Wheeler, J.W.

    1976-07-01

    A fully relativistic finite temperature many body theory is constructed and used to examine the bulk properties of a system of strongly interacting baryons. The strong interactions are described by a two parameter phenomenological model fit to a simple description of nuclear matter at T = 0. The zero temperature equation of state for such a system which has already been discussed in the literature was developed to give a realistic description of nuclear matter. The model presented here is the exact finite temperature extension of that model. The effect of the inclusion of baryon pairs for T greater than or equal to 2mc/sup 2//k is discussed in detail. The phase transition identified with nuclear matter vanishes for system temperatures in excess of T/sub C/ = 1.034 x 10/sup 11/ /sup 0/K. All values of epsilon (P,T) correspond to systems that are causal in the sense that the locally determined speed of sound never exceeds the speed of light.

  9. Finite temperature system of strongly interacting baryons

    International Nuclear Information System (INIS)

    Bowers, R.L.; Gleeson, A.M.; Pedigo, R.D.; Wheeler, J.W.

    1976-07-01

    A fully relativistic finite temperature many body theory is constructed and used to examine the bulk properties of a system of strongly interacting baryons. The strong interactions are described by a two parameter phenomenological model fit to a simple description of nuclear matter at T = 0. The zero temperature equation of state for such a system which has already been discussed in the literature was developed to give a realistic description of nuclear matter. The model presented here is the exact finite temperature extension of that model. The effect of the inclusion of baryon pairs for T greater than or equal to 2mc 2 /k is discussed in detail. The phase transition identified with nuclear matter vanishes for system temperatures in excess of T/sub C/ = 1.034 x 10 11 0 K. All values of epsilon (P,T) correspond to systems that are causal in the sense that the locally determined speed of sound never exceeds the speed of light

  10. Holographic gauge mediation via strongly coupled messengers

    International Nuclear Information System (INIS)

    McGuirk, Paul; Shiu, Gary; Sumitomo, Yoske

    2010-01-01

    We consider a relative of semidirect gauge mediation where the hidden sector exists at large 't Hooft coupling. Such scenarios can be difficult to describe using perturbative field theory methods but may fall into the class of holographic gauge mediation scenarios, meaning that they are amenable to the techniques of gauge/gravity duality. We use a recently found gravity solution to examine one such case, where the hidden sector is a cascading gauge theory resulting in a confinement scale not much smaller than the messenger mass. In the original construction of holographic gauge mediation, as in other examples of semidirect gauge mediation at strong coupling, the primary contributions to visible sector soft terms come from weakly coupled messenger mesons. In contrast to these examples, we describe the dual of a gauge theory where there are significant contributions from scales in which the strongly coupled messenger quarks are the effective degrees of freedom. In this regime, the visible sector gaugino mass can be calculated entirely from holography.

  11. NMR study of strongly correlated electron systems

    Science.gov (United States)

    Kitaoka, Y.; Tou, H.; Zheng, G.-q.; Ishida, K.; Asayama, K.; Kobayashi, T. C.; Kohda, A.; Takeshita, N.; Amaya, K.; Onuki, Y.; Geibel, G.; Schank, C.; Steglich, F.

    1995-02-01

    Various types of ground states in strongly correlated electron systems have been systematically investigated by means of NMR/NQR at low temperatures under high magnetic field and pressure. We focus on two well-known heavy-electron families, CeCu 2X 2 (X = Si and Ge) (Ce(122)) and UM 2Al 3 (M = Ni and Pd) (U(123)). The Cu NQR experiments on CeCu 2X 2 under high pressure indicate that the physical property of CeCu 2Ge 2 at high pressure, i.e. above the transition at 7.6 GPa from antiferromagnetic (AF) to superconductivity, are clearly related to tha CeCu 2Si 2 at ambient pressure. In addition to the H-T phase diagram established below 7 T, NMR and specific heat experiments on polycrystal CeCu 2.05Si 2 have revealed the presence of a new phase above 7 T. In a high-quality polycrystal of UPd 2Al 3 with a record high- Tc of 2 K at ambient pressure and the narrowest Al NQR line width, the nuclear-spin lattice relaxation rate, 27(1/ T1) measured in zero field has been found to obey the T3 law down to 0.13 K, giving strong evidence that the energy gap vanishes along lines on the Fermi surface. Thus it seems that all heavy-electron superconductors exhibit lines of zero gap, regardless of their different magnetic properties.

  12. Tracking Oxidation During Transport of Trace Gases in Air from the Northern to Southern Hemisphere

    Science.gov (United States)

    Montzka, S. A.; Moore, F. L.; Atlas, E. L.; Parrish, D. D.; Miller, B. R.; Sweeney, C.; McKain, K.; Hall, B. D.; Siso, C.; Crotwell, M.; Hintsa, E. J.; Elkins, J. W.; Blake, D. R.; Barletta, B.; Meinardi, S.; Claxton, T.; Hossaini, R.

    2017-12-01

    Trace gas mole fractions contain the imprint of recent influences on an air mass such as sources, transport, and oxidation. Covariations among the many gases measured from flasks during ATom and HIPPO, and from the ongoing NOAA cooperative air sampling program enable recent influences to be identified from a wide range of sources including industrial activity, biomass burning, emissions from wetlands, and uptake by terrestrial ecosystems. In this work we explore the evolution of trace gas concentrations owing to atmospheric oxidation as air masses pass through the tropics, the atmospheric region with the highest concentrations of the hydroxyl radical. Variations in C2-C5 hydrocarbon concentrations downwind of source regions provide a measure of photochemical ageing in an air mass since emission, but they become less useful when tracking photochemical ageing as air is transported from the NH into the SH owing to their low mixing ratios, lifetimes that are very short relative to transport times, non-industrial sources in the tropics (e.g., biomass burning), and southern hemispheric sources. Instead, we consider a range of trace gases and trace gas pairs that provide a measure of photochemical processing as air transits the tropics. To be useful in this analysis, these trace gases would have lifetimes comparable to interhemispheric transport times, emissions arising from only the NH at constant relative magnitudes, and concentrations sufficient to allow precise and accurate measurements in both hemispheres. Some anthropogenically-emitted chlorinated hydrocarbons meet these requirements and have been measured during ATom, HIPPO, and from NOAA's ongoing surface sampling efforts. Consideration of these results and their implications for tracking photochemical processing in air as it is transported across the tropics will be presented.

  13. Strongly anisotropic in-plane thermal transport in single-layer black phosphorene.

    Science.gov (United States)

    Jain, Ankit; McGaughey, Alan J H

    2015-02-17

    Using first principles calculations, we predict the thermal conductivity of the two-dimensional materials black phosphorene and blue phosphorene. Black phosphorene has an unprecedented thermal conductivity anisotropy ratio of three, with predicted values of 110 W/m-K and 36 W/m-K along its armchair and zigzag directions at a temperature of 300 K. For blue phosphorene, which is isotropic with a zigzag structure, the predicted value is 78 W/m-K. The two allotropes show strikingly different thermal conductivity accumulation, with phonons of mean free paths between 10 nm and 1 μm dominating in black phosphorene, while a much narrower band of mean free paths (50-200 nm) dominate in blue phosphorene. Black phosphorene shows intriguing potential for strain-tuning of its thermal conductivity tensor.

  14. Strongly anisotropic in-plane thermal transport in single-layer black phosphorene

    OpenAIRE

    Ankit Jain; Alan J. H. McGaughey

    2015-01-01

    Using first principles calculations, we predict the thermal conductivity of the two-dimensional materials black phosphorene and blue phosphorene. Black phosphorene has an unprecedented thermal conductivity anisotropy ratio of three, with predicted values of 110?W/m-K and 36?W/m-K along its armchair and zigzag directions at a temperature of 300?K. For blue phosphorene, which is isotropic with a zigzag structure, the predicted value is 78?W/m-K. The two allotropes show strikingly different ther...

  15. High-temperature stability of electron transport in semiconductors with strong spin-orbital interaction

    Science.gov (United States)

    Tomaka, G.; Grendysa, J.; ŚliŻ, P.; Becker, C. R.; Polit, J.; Wojnarowska, R.; Stadler, A.; Sheregii, E. M.

    2016-05-01

    Experimental results of the magnetotransport measurements (longitudinal magnetoresistance Rx x and the Hall resistance Rx y) are presented over a wide interval of temperatures for several samples of Hg1 -xCdxTe (x ≈0.13 -0.15 ) grown by MBE—thin layers (thickness about 100 nm) strained and not strained and thick ones with thickness about 1 μ m . An amazing temperature stability of the SdH-oscillation period and amplitude is observed in the entire temperature interval of measurements up to 50 K. Moreover, the quantum Hall effect (QHE) behavior of the Hall resistance is registered in the same temperature interval. These peculiarities of the Rx x and Rx y for strained thin layers are interpreted using quantum Hall conductivity (QHC) on topologically protected surface states (TPSS) [C. Brüne et al., Phys. Rev. Lett. 106, 126803 (2011), 10.1103/PhysRevLett.106.126803]. In the case of not strained layers it is assumed that the QHC on the TPSS (or on the resonant interface states) contributes also to the conductance of the bulk samples.

  16. Enhanced thermal photon and dilepton production in strongly coupled = 4 SYM plasma in strong magnetic field

    Science.gov (United States)

    Mamo, Kiminad A.

    2013-08-01

    We calculate the DC conductivity tensor of strongly coupled = 4 super-Yang-Mills (SYM) plasma in a presence of a strong external magnetic field B ≫ T 2 by using its gravity dual and employing both the RG flow approach and membrane paradigm which give the same results. We find that, since the magnetic field B induces anisotropy in the plasma, different components of the DC conductivity tensor have different magnitudes depending on whether its components are in the direction of the magnetic field B. In particular, we find that a component of the DC conductivity tensor in the direction of the magnetic field B increases linearly with B while the other components (which are not in the direction of the magnetic field B) are independent of it. These results are consistent with the lattice computations of the DC conductivity tensor of the QCD plasma in an external magnetic field B. Using the DC conductivity tensor, we calculate the soft or low-frequency thermal photon and dilepton production rates of the strongly coupled = 4 SYM plasma in the presence of the strong external magnetic field B ≫ T 2. We find that the strong magnetic field B enhances both the thermal photon and dilepton production rates of the strongly coupled = 4 SYM plasma in a qualitative agreement with the experimentally observed enhancements at the heavy-ion collision experiments.

  17. Convex Modeling of Interactions with Strong Heredity.

    Science.gov (United States)

    Haris, Asad; Witten, Daniela; Simon, Noah

    2016-01-01

    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.

  18. Strong Turbulence in Low-beta Plasmas

    DEFF Research Database (Denmark)

    Tchen, C. M.; Pécseli, Hans; Larsen, Søren Ejling

    1980-01-01

    An investigation of the spectral structure of turbulence in a plasma confined by a strong homogeneous magnetic field was made by means of a fluid description. The turbulent spectrum is divided into subranges. Mean gradients of velocity and density excite turbulent motions, and govern the production...... subrange. The spectra of velocity and potential fluctuations interact in the coupling subrange, and the energy is transferred along the spectrum in the inertia subrange. Applying the method of cascade decomposition, the spectral laws k-3, k-3, k-2 are obtained for the velocity fluctuations, and k-3, k-5, k......-3/2 for the potential fluctuations in the production, coupling and inertia subranges, respectively. The coefficient of Bohm diffusion is reproduced, and its role in electrostatic coupling is derived. Comparison is made with measured power laws reported in the literature, from Q-devices, hot...

  19. Strong crystal size effect on deformation twinning

    DEFF Research Database (Denmark)

    Yu, Qian; Shan, Zhi-Wei; Li, Ju

    2010-01-01

    find that the stress required for deformation twinning increases drastically with decreasing sample size of a titanium alloy single crystal7, 8, until the sample size is reduced to one micrometre, below which the deformation twinning is entirely replaced by less correlated, ordinary dislocation...... plasticity. Accompanying the transition in deformation mechanism, the maximum flow stress of the submicrometre-sized pillars was observed to saturate at a value close to titanium’s ideal strength9, 10. We develop a ‘stimulated slip’ model to explain the strong size dependence of deformation twinning....... The sample size in transition is relatively large and easily accessible in experiments, making our understanding of size dependence11, 12, 13, 14, 15, 16, 17 relevant for applications....

  20. Towards Integrated Marmara Strong Motion Network

    Science.gov (United States)

    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

  1. Strongly coupled band in 140Gd

    International Nuclear Information System (INIS)

    Falla-Sotelo, F.; Oliveira, J.R.B.; Rao, M.N.

    2005-01-01

    Several high-K states are known to exist in the mass 130-140 region. For the N=74 even-even isotopes, Kπ = 8 - isomers, with lifetimes ranging from ns to ms, are known in 128 Xe, 130 Ba, 132 Ce, 134 Nd, 136 Sm, and 138 Gd[. In 140 Gd, we have observed for the first time a band also based on an Iπ = 8 - state. This could be the first case of a Kπ = 8 - state observed in an N=76 even-even isotope. The systematics of the Kπ = 8 - isomeric states in N=74 isotopes has been studied by A.M. Bruce et al. These states decay towards the K = 0 ground state band, and the transitions are K-forbidden. The 140 Gd case presents strong similarities but also some significant differences with relation to the N=74 isotopes. We propose the same configuration but with larger deformation in 140 Gd

  2. Thomson scattering in strong external fields

    Science.gov (United States)

    Varró, S.; Ehlotzky, F.

    1992-09-01

    In the present paper we shall investigate relativistic Thomson scattering in two external fields. A free classical electron will be embedded in a strong, constant and homogeneous magnetic field and in a powerful electromagnetic field. Both fields will be considered in the Redmond configuration, in which case the electromagnetic wave is circularly polarized and propagates in the direction of the homogeneous magnetic field. The electron will be allowed to have arbitrary initial conditions and the electromagnetic wave will be switched on either suddenly or adiabatically. We shall present the exact solution of the Lorentz equation of motion in the above external field configuration and we shall evaluate the spectrum and cross sections of the scattered radiation. In particular, we shall consider scattering close to resonance and we shall compare our results with the findings of earlier work.

  3. Strongly Interacting Matter at High Energy Density

    International Nuclear Information System (INIS)

    McLerran, L.

    2008-01-01

    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 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

  4. Strong curvature effects in Neumann wave problems

    DEFF Research Database (Denmark)

    Willatzen, Morten; Pors, A.; Gravesen, Jens

    2012-01-01

    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 Schro¨dinger 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...

  5. Neutrino oscillations in strong magnetic fields

    International Nuclear Information System (INIS)

    Likhachev, G.G.; Studenikin, A.I.

    1994-07-01

    Neutrino conversion processes between two neutrino species and the corresponding oscillations induced by strong magnetic fields are considered. The value of the critical strength of magnetic field B cr as a function of characteristics of neutrinos in vacuum (Δm 2 ν , mixing angle θ), effective particle density of matter n eff , neutrino (transition) magnetic moment μ-tilde and energy E is introduced. It is shown that the neutrino conversion and oscillations effects induced by magnetic fields B ≥ B cr are important and may result in the depletion of the initial type of ν's in the bunch. A possible increase of these effects in the case when neutrinos pass through a sudden decrease of density of matter (''cross-boundary effect'') and applications to neutrinos from neutron stars and supernova are discussed. (author). 25 refs

  6. Cosmological applications of strong gravitational lensing

    DEFF Research Database (Denmark)

    Paraficz, Danuta

    value of the energy density of the two above components, together with measuring the Hubble constant that determines the age of the Universe, is a major goal of modern astrophysics. An interesting method for estimating these parameters is strong gravitational lensing of quasars (QSOs). As shown......One of the most intriguing recent results in physics is the growing evidence that an unknown energy field and an unknown kind of matter are the major components of the Universe (70% and 30%, respectively; see e.g. Riess et al. 1998, Spergel et al. 2007). Understanding and estimating the precise...... by Refsdal (1964), H0, !m and !! can be measured based on the time delay ("t) between multiply lensed images of QSOs, because "t depends on H0 and on the distances to lens and source, hence!m and !!. Determination of cosmological parameters using gravitational lensing suffers from some degeneracies...

  7. Weak and strong typicality in quantum systems.

    Science.gov (United States)

    Santos, Lea F; Polkovnikov, Anatoli; Rigol, Marcos

    2012-07-01

    We study the properties of mixed states obtained from eigenstates of many-body lattice Hamiltonians after tracing out part of the lattice. Two scenarios emerge for generic systems: (i) The diagonal entropy becomes equivalent to the thermodynamic entropy when a few sites are traced out (weak typicality); and (ii) the von Neumann (entanglement) entropy becomes equivalent to the thermodynamic entropy when a large fraction of the lattice is traced out (strong typicality). Remarkably, the results for few-body observables obtained with the reduced, diagonal, and canonical density matrices are very similar to each other, no matter which fraction of the lattice is traced out. Hence, for all physical quantities studied here, the results in the diagonal ensemble match the thermal predictions.

  8. Machine Learning Phases of Strongly Correlated Fermions

    Directory of Open Access Journals (Sweden)

    Kelvin Ch’ng

    2017-08-01

    Full Text Available Machine learning offers an unprecedented perspective for the problem of classifying phases in condensed matter physics. We employ neural-network machine learning techniques to distinguish finite-temperature phases of the strongly correlated fermions on cubic lattices. We show that a three-dimensional convolutional network trained on auxiliary field configurations produced by quantum Monte Carlo simulations of the Hubbard model can correctly predict the magnetic phase diagram of the model at the average density of one (half filling. We then use the network, trained at half filling, to explore the trend in the transition temperature as the system is doped away from half filling. This transfer learning approach predicts that the instability to the magnetic phase extends to at least 5% doping in this region. Our results pave the way for other machine learning applications in correlated quantum many-body systems.

  9. The new <Strong Italian Earthquakes>>

    Directory of Open Access Journals (Sweden)

    G. Valensise

    1995-06-01

    Full Text Available We describe a new catalogue of strong ltalian earthquakes that the Istituto Nazionale di Geofisica in collaboration with SGA, has recently made available to the international scientific community and to the general public. The new catalogue differs from previous efforts in that for each event the usual seismic parameters are complemented by a list of intensity rated localities, a complete list of relevant references, a series of synoptic comments describing different aspects of the earthquake phenomenology. and in most cases even the text of the original written sources. The printed part of the catalogue has been published as a special monograph which contains also a computer version of the full database in the form of a CD-ROM. The software package includes a computer program for retrieving, selecting and displaying the catalogue data.

  10. Strong curvature effects in Neumann wave problems

    International Nuclear Information System (INIS)

    Willatzen, M.; Pors, A.; Gravesen, J.

    2012-01-01

    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 Schrödinger 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.

  11. Bodrum Strong Motion Network, Mugla, Turkey

    Science.gov (United States)

    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.

  12. Is It Possible to Predict Strong Earthquakes?

    Science.gov (United States)

    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.

  13. Transport processes in magnetically confined plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Callen, J.D.

    1991-12-01

    Intensified studies of plasma transport in toroidal plasmas over the past three to five years have progressed through increased understanding in some areas and changed perceptions about the most important issues in other areas. Recent developments are reviewed for six selected topics: edge fluctuations and transport; L-H mode transition; core fluctuations; modern plasma turbulence theory; transient transport; and global scaling. Some of the developments that are highlighted include: the role of a strongly sheared poloidal flow in edge plasma turbulence, transport and the L-H transition; change of focus from {kappa}{perpendicular}{rho}s {approximately} 1 to {kappa}{perpendicular}{rho}s {much_lt} 1 fluctuations in tokamak plasmas; modern Direct-Interaction-Approximation plasma turbulence and hybrid fluid/kinetic theoretical models; and transient transport experiments that are raising fundamental questions about our conceptions of local transport processes in tokamaks. 104 refs., 6 figs.

  14. Transport processes in magnetically confined plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Callen, J.D.

    1991-12-01

    Intensified studies of plasma transport in toroidal plasmas over the past three to five years have progressed through increased understanding in some areas and changed perceptions about the most important issues in other areas. Recent developments are reviewed for six selected topics: edge fluctuations and transport; L-H mode transition; core fluctuations; modern plasma turbulence theory; transient transport; and global scaling. Some of the developments that are highlighted include: the role of a strongly sheared poloidal flow in edge plasma turbulence, transport and the L-H transition; change of focus from {kappa}{perpendicular}{rho}s {approximately} 1 to {kappa}{perpendicular}{rho}s {much lt} 1 fluctuations in tokamak plasmas; modern Direct-Interaction-Approximation plasma turbulence and hybrid fluid/kinetic theoretical models; and transient transport experiments that are raising fundamental questions about our conceptions of local transport processes in tokamaks. 104 refs., 6 figs.

  15. Tracer transport in fractured rocks

    International Nuclear Information System (INIS)

    Tsang, C.F.; Tsang, Y.W.; Hale, F.V.

    1988-07-01

    Recent interest in the safety of toxic waste underground disposal and nuclear waste geologic repositories has motivated many studies of tracer transport in fractured media. Fractures occur in most geologic formations and introduce a high degree of heterogeneity. Within each fracture, the aperture is not constant in value but strongly varying. Thus for such media, tracer tends to flow through preferred flowpaths or channels within the fractures. Along each of these channels, the aperture is also strongly varying. A detailed analysis is carried out on a 2D single fracture with variable apertures and the flow through channels is demonstrated. The channels defined this way are not rigidly set pathways for tracer transport, but are the preferred flow paths in the sense of stream-tubes in the potential theory. It is shown that such variable-aperture channels can be characterized by an aperture probability distribution function, and not by the exact deterministic geometric locations. We also demonstrate that the 2D tracer transport in a fracture can be calculated by a model of a system of 1D channels characterized by this distribution function only. Due to the channeling character of tracer transport in fractured rock, random point measurements of tracer breakthrough curves may give results with a wide spread in value due to statistical fluctuations. The present paper suggests that such a wide spread can probably be greatly reduced by making line/areal (or multiple) measurements covering a few spatial correlation lengths. 13 refs., 11 figs., 1 tab

  16. 76 FR 40686 - Public Input for the Launch of the Strong Cities, Strong Communities Visioning Challenge

    Science.gov (United States)

    2011-07-11

    ... Energy, U.S. Department of Education, U.S. Department of Justice, U.S. Department of Transportation, U.S..., infrastructure, and economic and social resources (e.g., industry clusters, workforce development), and economic...., significant population loss, long-term economic decline, high levels of poverty and unemployment, low property...

  17. Strong Motion Seismograph Based On MEMS Accelerometer

    Science.gov (United States)

    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

  18. Beam transport

    International Nuclear Information System (INIS)

    1988-01-01

    Considerable experience has now been gained with the various beam transport lines, and a number of minor changes have been made to improve the ease of operation. These include: replacement of certain little-used slits by profile monitors (harps or scanners); relocation of steering magnets, closer to diagnostic harps or profile scanners; installation of a scanner inside the isocentric neutron therapy system; and conversion of a 2-doublet quadrupole telescope (on the neutron therapy beamline) to a 2-triplet telescope. The beam-swinger project has been delayed by very late delivery of the magnet iron to the manufacturer, but is now progressing smoothly. The K=600 spectrometer magnets have now been delivered and are being assembled for field mapping. The x,y-table with its associated mapping equipment is complete, together with the driver software. One of the experimental areas has been dedicated to the production of collimated neutron beams and has been equipped with a bending magnet and beam dump, together with steel collimators fixed at 4 degrees intervals from 0 degrees to 16 degrees. Changes to the target cooling and shielding system for isotope production have led to a request for much smaller beam spot sizes on target, and preparations have been made for rearrangement of the isotope beamline to permit installation of quadrupole triplets on the three beamlines after the switching magnet. A practical system of quadrupoles for matching beam properties to the spectrometer has been designed. 6 figs

  19. Transports under surveillance

    International Nuclear Information System (INIS)

    Jouette, I.

    2016-01-01

    Each year 770.000 nuclear transports are performed in France representing less than 3% of the transport of dangerous materials. This article review various aspects of nuclear transport: modes of transportation, packages, current legislation, safety and surveillance. A map presents the transport route of vitrified wastes from Sellafield plant to the Zwilag storing center in Switzerland at one moment this transport crosses France and another map presents the transport routes involved in the nuclear fuel cycle in France. (A.C.)

  20. Chemical transport reactions

    CERN Document Server

    Schäfer, Harald

    2013-01-01

    Chemical Transport Reactions focuses on the processes and reactions involved in the transport of solid or liquid substances to form vapor phase reaction products. The publication first offers information on experimental and theoretical principles and the transport of solid substances and its special applications. Discussions focus on calculation of the transport effect of heterogeneous equilibria for a gas motion between equilibrium spaces; transport effect and the thermodynamic quantities of the transport reaction; separation and purification of substances by means of material transport; and

  1. Ion Motion in a Plasma Interacting with Strong Magnetic Fields

    International Nuclear Information System (INIS)

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

    1999-01-01

    The interaction of a plasma with strong magnetic fields takes place in many laboratory experiments and astrophysical plasmas. Applying a strong magnetic field to the plasma may result in plasma displacement, magnetization, or the formation of instabilities. Important phenomena in plasma, such as the energy transport and the momentum balance, take a different form in each case. We study this interaction in a plasma that carries a short-duration (80-ns) current pulse, generating a magnetic field of up to 17 kG. The evolution of the magnetic field, plasma density, ion velocities, and electric fields are determined before and during the current pulse. The dependence of the plasma limiting current on the plasma density and composition are studied and compared to theoretical models based on the different phenomena. When the plasma collisionality is low, three typical velocities should be taken into consideration: the proton and heavier-ion Alfven velocities (v A p and v A h , respectively) and the EMHD magnetic-field penetration velocity into the plasma (v EMHD ). If both Alfven velocities are larger than v EMHD the plasma is pushed ahead of the magnetic piston and the magnetic field energy is dissipated into ion kinetic energy. If v EMHD is the largest of three velocities, the plasma become magnetized and the ions acquire a small axial momentum only. Different ion species may drift in different directions along the current lines. In this case, the magnetic field energy is probably dissipated into electron thermal energy. When vs > V EMHD > vi, as in the case of one of our experiments, ion mass separation occurs. The protons are pushed ahead of the piston while the heavier-ions become magnetized. Since the plasma electrons are unmagnetized they cannot cross the piston, and the heavy ions are probably charge-neutralized by electrons originating from the cathode that are 'born' magnetized

  2. Interhemispheric Transfer in Down’s Syndrome

    Directory of Open Access Journals (Sweden)

    C. M. J. Braun

    1992-01-01

    Full Text Available Callosal agenesics and callosotomized epileptics manifest markedly increasing simple visual reaction time (SVRT from conditions of ipsilateral to contralateral stimulus-response relation (SRR. In the contralateral SRR, a response is presumed possible because of presence of other commissures (anterior, intercollicular. The SRR effect is prolonged presumably because the remaining commissures are less efficient than the corpus callosum in relaying necessary visual or motor information. Consequently, the SRR effect is believed to correspond to callosal relay time (CRT in the normal subject. However, both callosal agenesics and callosotomy patients manifest general slowing of SVRT in addition to a prolonged SRR effect. These patients have massive extra-callosal damage which could plausibly cause both the SVRT and the CUD prolongation. If such were the case, the CRT inference would be in jeopardy. A test of the CRT inference is therefore required where patients with massive diffuse extra-callosal brain damage and normal callosi would show marked general SVRT prolongation and a normal SRR effect. Four trisomy-21 (T21 males were compared to age and sex-matched normal controls. General SVRT was highly significantly prolonged in T21, but the CUD was nearly identical in both groups.

  3. Thermal infrared anomalies of several strong earthquakes.

    Science.gov (United States)

    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.

  4. Demand for Neste's City products grows strongly

    International Nuclear Information System (INIS)

    Anon.

    1994-01-01

    Finland's oil, chemicals, and gas company, Neste Corporation, is well on the road to better financial performance after a very difficult year in 1992. Among the factors contributing to this optimism are Neste's pioneering low environmental impact traffic fuels. Neste Corporation's net sales in 1993 rose 9.9 % on 1992 figures to USD 11,011 million. Investments totalled USD 681 million. Profitability also improved during 1993, and the operating margin rose by 57 %, despite the recession affecting the Finnish economy and the instability of the international market. The operational loss for the year before extraordinary items, reserves, and taxes was USD 265 million, one-third less than in 1992. Neste's strategy has been to achieve a strong position in the Baltic Rim region by becoming the quality and cost leader in oil refining, and by expanding Neste's position in its key markets. A total of 3.3 million tonnes of petroleum products were exported from Finland in 1993. Neste's most important export markets were Sweden, Germany, Poland, the Baltic countries, and the St. Petersburg region. Some 20 % of exports went to customers outside Europe. In addition to Finland, Neste has concertedly developed its service station network in Poland and the Baltic countries

  5. Strong Correlation Physics in Aromatic Hydrocarbon Superconductors

    Science.gov (United States)

    Capone, Massimo; Giovannetti, Gianluca

    2012-02-01

    We show, by means of ab-initio calculations, that electron-electron correlations play an important role in doped aromatic hydrocarbon superconductors, including potassium doped picene with Tc= 18K [1], coronene and phenanthrene [2]. For the case of picene the inclusion of exchange interactions by means of hybrid functionals reproduces the correct gap for the undoped compound and predicts an antiferromagnetic state for x=3, where superconductivity has been observed [3]. The latter finding is compatible with a sizable value of the correlation strength. The differences between the different compounds are analyzed and results of Dynamical Mean-Field Theory including both correlation effects and electron-phonon interactions are presented. Finally we discuss the consequences of strong correlations in an organic superconductor in relation to the properties of Cs3C60, in which electron correlations drive an antiferromagnetic state [4] but also lead to an enhancement of superconductivity [5]. 1. R. Mitsuhashi et al. Nature 464, 76 (2010)2. X.F. Wang et al, Nat. Comm. 2, 507 (2011)3. G. Giovannetti and M. Capone, Phys. Rev. B 83, 134508 (2011)4. Y. Takabayashi et al., Science 323, 1585 (2009)5. M. Capone et al. Rev. Mod. Phys. 81, 943 (2009

  6. Binary Polymer Brushes of Strongly Immiscible Polymers.

    Science.gov (United States)

    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.

  7. Quasinormal Modes and Strong Cosmic Censorship

    Science.gov (United States)

    Cardoso, Vitor; Costa, João L.; Destounis, Kyriakos; Hintz, Peter; Jansen, Aron

    2018-01-01

    The fate of Cauchy horizons, such as those found inside charged black holes, is intrinsically connected to the decay of small perturbations exterior to the event horizon. As such, the validity of the strong cosmic censorship (SCC) conjecture is tied to how effectively the exterior damps fluctuations. Here, we study massless scalar fields in the exterior of Reissner-Nordström-de Sitter black holes. Their decay rates are governed by quasinormal modes of the black hole. We identify three families of modes in these spacetimes: one directly linked to the photon sphere, well described by standard WKB-type tools; another family whose existence and time scale is closely related to the de Sitter horizon; finally, a third family which dominates for near-extremally charged black holes and which is also present in asymptotically flat spacetimes. The last two families of modes seem to have gone unnoticed in the literature. We give a detailed description of linear scalar perturbations of such black holes, and conjecture that SCC is violated in the near extremal regime.

  8. Strong coupling from the Hubbard model

    Science.gov (United States)

    Minahan, Joseph A.

    2006-10-01

    It was recently observed that the one-dimensional half-filled Hubbard model reproduces the known part of the perturbative spectrum of planar {\\cal N}=4 super Yang Mills in the SU(2) sector. Assuming that this identification is valid beyond perturbation theory, we investigate the behaviour of this spectrum as the 't Hooft parameter λ becomes large. We show that the full dimension Δ of the Konishi superpartner is the solution of a sixth-order polynomial while Δ for a bare dimension 5 operator is the solution of a cubic. In both cases, the equations can be solved easily as a series expansion for both small and large λ and the equations can be inverted to express λ as an explicit function of Δ. We then consider more general operators and show how Δ depends on λ in the strong coupling limit. We are also able to distinguish those states in the Hubbard model which correspond to the gauge-invariant operators for all values of λ. Finally, we compare our results with known results for strings on AdS5 × S5, where we find agreement for a range of R-charges.

  9. Strongly coupled band in {sup 140}Gd

    Energy Technology Data Exchange (ETDEWEB)

    Falla-Sotelo, F.; Oliveira, J.R.B.; Rao, M.N. [Instituto de Fisica, Universidade de Sao Paulo, Sao Paulo (Brazil)] (and others)

    2005-07-01

    Several high-K states are known to exist in the mass 130-140 region. For the N=74 even-even isotopes, K{pi} = 8{sup -} isomers, with lifetimes ranging from ns to ms, are known in {sup 128}Xe, {sup 130}Ba, {sup 132}Ce, {sup 134}Nd, {sup 136}Sm, and {sup 138}Gd[. In {sup 140}Gd, we have observed for the first time a band also based on an I{pi} = 8{sup -} state. This could be the first case of a K{pi} = 8{sup -} state observed in an N=76 even-even isotope. The systematics of the K{pi} = 8{sup -} isomeric states in N=74 isotopes has been studied by A.M. Bruce et al. These states decay towards the K = 0 ground state band, and the transitions are K-forbidden. The {sup 140}Gd case presents strong similarities but also some significant differences with relation to the N=74 isotopes. We propose the same configuration but with larger deformation in {sup 140}Gd.

  10. Stable states in a strong IR field

    Science.gov (United States)

    Zhong, Changchun; Robicheaux, Francis

    2015-05-01

    It is found that 10% of atoms stay in the quasi-stable states after being exposed to intense laser or microwave (MW) pulses, even though the pulses' intensity is much stronger than that needed for static fields ionization. The reason why atoms survive those strong pulses has attracted growing attentions. A. Arakelyan et al. have observed the optical spectra of the surviving Lithium atoms after interaction with intense 38-GHz MW fields for more than 1000 cycles, and the spectra exhibit a periodic train of peaks 38 GHz apart. It suggests that those weakly bound Rydberg electrons seldom go back to the ionic core, where the cycle average energy exchange happens. In this study, we are interested in the electron behavior in the presence of intense infrared fields with a much shorter wavelength (1000 nm). By solving the full 3D time dependent Schrodinger equation, we calculate the spectra of the surviving atoms under intense IR fields. Our numerical calculations show atoms survive the intense field in quasi-stable states for a long time, and the optical spectra are obviously modulated by the IR frequency. Through tuning the ponderomotive energy, we see how field parameters affect the behavior of electrons. Different atoms, such as Hydrogen, Helium, Lithium, and Sodium, are tested to see how atom's energy structures influence the results.

  11. Strong reinforcing selection in a Texas wildflower.

    Science.gov (United States)

    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. Copyright © 2014 Elsevier Ltd. All rights reserved.

  12. Thermal Infrared Anomalies of Several Strong Earthquakes

    Directory of Open Access Journals (Sweden)

    Congxin Wei

    2013-01-01

    Full Text Available 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.

  13. Quantum centipedes with strong global constraint

    Science.gov (United States)

    Grange, Pascal

    2017-06-01

    A centipede made of N quantum walkers on a one-dimensional lattice is considered. The distance between two consecutive legs is either one or two lattice spacings, and a global constraint is imposed: the maximal distance between the first and last leg is N  +  1. This is the strongest global constraint compatible with walking. For an initial value of the wave function corresponding to a localized configuration at the origin, the probability law of the first leg of the centipede can be expressed in closed form in terms of Bessel functions. The dispersion relation and the group velocities are worked out exactly. Their maximal group velocity goes to zero when N goes to infinity, which is in contrast with the behaviour of group velocities of quantum centipedes without global constraint, which were recently shown by Krapivsky, Luck and Mallick to give rise to ballistic spreading of extremal wave-front at non-zero velocity in the large-N limit. The corresponding Hamiltonians are implemented numerically, based on a block structure of the space of configurations corresponding to compositions of the integer N. The growth of the maximal group velocity when the strong constraint is gradually relaxed is explored, and observed to be linear in the density of gaps allowed in the configurations. Heuristic arguments are presented to infer that the large-N limit of the globally constrained model can yield finite group velocities provided the allowed number of gaps is a finite fraction of N.

  14. Strongly correlated superconductivity and quantum criticality

    Science.gov (United States)

    Tremblay, A.-M. S.

    Doped Mott insulators and doped charge-transfer insulators describe classes of materials that can exhibit unconventional superconducting ground states. Examples include the cuprates and the layered organic superconductors of the BEDT family. I present results obtained from plaquette cellular dynamical mean-field theory. Continuous-time quantum Monte Carlo evaluation of the hybridization expansion allows one to study the models in the large interaction limit where quasiparticles can disappear. The normal state which is unstable to the superconducting state exhibits a first-order transition between a pseudogap and a correlated metal phase. That transition is the finite-doping extension of the metal-insulator transition obtained at half-filling. This transition serves as an organizing principle for the normal and superconducting states of both cuprates and doped organic superconductors. In the less strongly correlated limit, these methods also describe the more conventional case where the superconducting dome surrounds an antiferromagnetic quantum critical point. Sponsored by NSERC RGPIN-2014-04584, CIFAR, Research Chair in the Theory of Quantum Materials.

  15. Strong liquid-crystalline polymeric compositions

    Science.gov (United States)

    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.

  16. Grassy Silica Nanoribbons and Strong Blue Luminescence

    Science.gov (United States)

    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.

  17. Toward a Strongly Interacting Scalar Higgs Particle

    International Nuclear Information System (INIS)

    Shalaby, Abouzeid M.; El-Houssieny, M.

    2008-01-01

    We calculate the vacuum energy of the non-Hermitian and PT symmetric (-gφ 4 ) 2+1 scalar field theory. Rather than the corresponding Hermitian theory and due to the asymptotic freedom property of the theory, the vacuum energy does not blow up for large energy scales which is a good sign to solve the hierarchy problem when using this model to break the U(1)xSU(2) symmetry in the standard model. The theory is strongly interacting and in fact, all the dimensionful parameters in the theory like mass and energy are finite even for very high energy scales. Moreover, relative to the vacuum energy for the Hermitian φ 4 theory, the vacuum energy of the non-Hermitian and PT symmetric (-gφ 4 ) 2+1 theory is tiny, which is a good sign toward the solution of the cosmological constant problem. Remarkably, these features of the non-Hermitian and PT symmetric (-gφ 4 ) 2+1 scalar field theory make it very plausible to be employed as a Higgs mechanism in the standard model instead of the problematic Hermitian Higgs mechanism

  18. Thermal Infrared Anomalies of Several Strong Earthquakes

    Science.gov (United States)

    Wei, Congxin; Guo, Xiao; Qin, Manzhong

    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. PMID:24222728

  19. Transporting particulate material

    Science.gov (United States)

    Aldred, Derek Leslie [North Hollywood, CA; Rader, Jeffrey A [North Hollywood, CA; Saunders, Timothy W [North Hollywood, CA

    2011-08-30

    A material transporting system comprises a material transporting apparatus (100) including a material transporting apparatus hopper structure (200, 202), which comprises at least one rotary transporting apparatus; a stationary hub structure (900) constraining and assisting the at least one rotary transporting apparatus; an outlet duct configuration (700) configured to permit material to exit therefrom and comprising at least one diverging portion (702, 702'); an outlet abutment configuration (800) configured to direct material to the outlet duct configuration; an outlet valve assembly from the material transporting system venting the material transporting system; and a moving wall configuration in the material transporting apparatus capable of assisting the material transporting apparatus in transporting material in the material transporting system. Material can be moved from the material transporting apparatus hopper structure to the outlet duct configuration through the at least one rotary transporting apparatus, the outlet abutment configuration, and the outlet valve assembly.

  20. Plant Transporter Identification

    DEFF Research Database (Denmark)

    Larsen, Bo

    Membrane transport proteins (transporters) play a critical role for numerous biological processes, by controlling the movements of ions and molecules in and out of cells. In plants, transporters thus function as gatekeepers between the plant and its surrounding environment and between organs......, tissues, cells and intracellular compartments. Since plants are highly compartmentalized organisms with complex transportation infrastructures, they consequently have many transporters. However, the vast majority of predicted transporters have not yet been experimentally verified to have transport...... activity. This project contains a review of the implemented methods, which have led to plant transporter identification, and present our progress on creating a high-throughput functional genomics transporter identification platform....

  1. Mass Transport within Soils

    Energy Technology Data Exchange (ETDEWEB)

    McKone, Thomas E.

    2009-03-01

    strongly on (1) the composition of the soil and physical state of the soil, (2) the chemical and physical properties of the substance of interest, and (3) transformation rates in soil. Our particular focus is on approaches for constructing soil-transport algorithms and soil-transport parameters for incorporation within multimedia fate models. We show how MTC's can be developed to construct a simple two-compartment air-soil system. We then demonstrate how a multi-layer-box-model approach for soil-mass balance converges to the exact analytical solution for concentration and mass balance. Finally, we demonstrate and evaluate the performance of the algorithms in a model with applications to the specimen chemicals benzene, hexachlorobenzene, lindane gammahexachlorocyclohexane, benzo(a)pyrene, nickel, and copper.

  2. Strong Coupling Gauge Theories in LHC ERA

    Science.gov (United States)

    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

  3. Transportation and the environment.

    NARCIS (Netherlands)

    Banister, D.; Anderton, K.; Bonilla, D.; Givoni, M.; Schwanen, T.

    2011-01-01

    The growth of CO2-intensive transport, mobility and the impact of transport on the environment are reviewed. The recent global exponential growth in transport is unsustainable and must end unless the transport sector can decarbonize. The paper examines solutions for low-carbon transport systems; the

  4. Strong ground motion spectra for layered media

    International Nuclear Information System (INIS)

    Askar, A.; Cakmak, A.S.; Engin, H.

    1977-01-01

    This article presents an analytic method and calculations of strong motion spectra for the energy, displacement, velocity and acceleration based on the physical and geometric ground properties at a site. Although earthquakes occur with large deformations and high stress intensities which necessarily lead to nonlinear phenomena, most analytical efforts to date have been based on linear analyses in engineering seismology and soil dynamics. There are, however, a wealth of problems such as the shifts in frequency, dispersion due to the amplitude, the generation of harmonics, removal of resonance infinities, which cannot be accounted for by a linear theory. In the study, the stress-strain law for soil is taken as tau=G 0 γ+G 1 γ 3 +etaγ where tau is the stress, γ is the strain, G 0 and G 1 are the elasticity coefficients and eta is the damping and are different in each layer. The above stress-strain law describes soils with hysterisis where the hysterisis loops for various amplitudes of the strain are no longer concentric ellipses as for linear relations but are oval shapes rotated with respect to each other similar to the materials with the Osgood-Ramberg law. It is observed that even slight nonlinearities may drastically alter the various response spectra from that given by linear analysis. In fact, primary waves cause resonance conditions such that secondary waves are generated. As a result, a weak energy transfer from the primary to the secondary waves takes place, thus altering the wave spectrum. The mathematical technique that is utilized for the solution of the nonlinear equation is a special perturbation method as an extension of Poincare's procedure. The method considers shifts in the frequencies which are determined by the boundedness of the energy

  5. Strong Algerian Earthquake Strikes Near Capital City

    Science.gov (United States)

    Ayadi, A.; Maouche, S.; Harbi, A.; Meghraoui, M.; Beldjoudi, H.; Oussadou, F.; Mahsas, A.; Benouar, D.; Heddar, A.; Rouchiche, Y.; Kherroubi, A.; Frogneux, M.; Lammali, K.; Benhamouda, F.; Sebaï, A.; Bourouis, S.; Alasset, P. J.; Aoudia, A.; Cakir, Z.; Merahi, M.; Nouar, O.; Yelles, A.; Bellik, A.; Briole, P.; Charade, O.; Thouvenot, F.; Semane, F.; Ferkoul, A.; Deramchi, A.; Haned, S. A.

    On 21 May 2003, a damaging earthquake of Mw 6.8 struck the region of Boumerdes 40 km east of Algiers in northern Algeria (Figure 1). The mainshock, which lasted ~ 36-40 s, had devastating effects and claimed about 2300 victims, caused more than 11,450 injuries, and left about 200,000 people homeless. It destroyed and seriously damaged around 180,000 housing units and 6000 public buildings with losses estimated at $5 billion. The mainshock was widely felt within a radius of ~ 400 km in Algeria. To the north, the earthquake was felt in southeastern Spain, including the Balearic Islands, and also in Sardinia and in southern France. The mainshock location, which was calculated at 36.91°N, 3.58°E (15 km offshore of Zemmouri; Figure 1), and the local magnitude (Md 6.4) are from seismic records of local stations. International seismological centers obtained Mw 6.8 (NEIC) with a thrust focal mechanism solution and 1.83 × 1026 dyne.cm for the seismic moment. A sequence of aftershocks affected the epicentral area with two strong shocks reaching Mw 5.8 on 27 and 29 May 2003. Field investigations allowed us to assign a maximum intensity X (European Macroseismic Scale 98) and to report rockfalls, minor surface cracks, and liquefaction phenomena. The mainshock was not associated with inland surface faulting, but one of the most striking coseismic effects is the coastal uplift and the backwash along the littoral of the Mitidja basin.

  6. Strong economic growth driving increased electricity consumption

    International Nuclear Information System (INIS)

    Tiusanen, P.

    2000-01-01

    The Finnish economy is growing faster today than anyone dared hope only a few years ago. Growth estimates for 2000 have already had to be raised. This strong level of economic growth has been reflected in electricity consumption, which has continued to increase, despite the exceptionally warm winter. A major part of this increased electricity usage has so far been met through imports. The continued growth in electricity imports has largely been a result of the fact that the good water level situation in Sweden and Norway, together with the mild winter, has kept electricity prices exceptionally low on the Nordic electricity exchange. The short period of low temperatures seen at the end of January showed, however, that this type of temperature fluctuation, combined with the restrictions that exist in regard to transfer capacity, can serve to push Nordic exchange electricity prices to record levels. This increase in price also highlights the fact that we are approaching a situation in which capacity will be insufficient to meet demand. A truly tough winter has not been seen since the Nordic region's electricity markets were deregulated. The lesson that needs to be learnt is that Finland needs sufficient capacity of her own to meet demand even during particularly cold winters. Finland used 77.9 billion kWh of electricity last year, up 1.6% or 1.3 billion kWh on 1998. This growth was relatively evenly distributed among different user groups. This year, electricity consumption is forecast to grow by 2-3%

  7. Kinetic theory for strongly coupled Coulomb systems

    Science.gov (United States)

    Dufty, James; Wrighton, Jeffrey

    2018-01-01

    The calculation of dynamical properties for matter under extreme conditions is a challenging task. The popular Kubo-Greenwood model exploits elements from equilibrium density-functional theory (DFT) that allow a detailed treatment of electron correlations, but its origin is largely phenomenological; traditional kinetic theories have a more secure foundation but are limited to weak ion-electron interactions. The objective here is to show how a combination of the two evolves naturally from the short-time limit for the generator of the effective single-electron dynamics governing time correlation functions without such limitations. This provides a theoretical context for the current DFT-related approach, the Kubo-Greenwood model, while showing the nature of its corrections. The method is to calculate the short-time dynamics in the single-electron subspace for a given configuration of the ions. This differs from the usual kinetic theory approach in which an average over the ions is performed as well. In this way the effective ion-electron interaction includes strong Coulomb coupling and is shown to be determined from DFT. The correlation functions have the form of the random-phase approximation for an inhomogeneous system but with renormalized ion-electron and electron-electron potentials. The dynamic structure function, density response function, and electrical conductivity are calculated as examples. The static local field corrections in the dielectric function are identified in this way. The current analysis is limited to semiclassical electrons (quantum statistical potentials), so important quantum conditions are excluded. However, a quantization of the kinetic theory is identified for broader application while awaiting its detailed derivation.

  8. The Astrophysics of Strongly Interacting Systems

    Science.gov (United States)

    Nerella, Tejaswi Venumadhav

    This thesis presents investigations in four areas of theoretical astrophysics: the production of sterile neutrino dark matter in the early Universe, the evolution of small-scale baryon perturbations during the epoch of cosmological recombination, the effect of primordial magnetic fields on the redshifted 21-cm emission from the pre-reionization era, and the nonlinear stability of tidally deformed neutron stars. In the first part of the thesis, we study the asymmetry-driven resonant production of 7 keV-scale sterile neutrino dark matter in the primordial Universe at temperatures T >~ 100 MeV. We report final DM phase space densities that are robust to uncertainties in the nature of the quark-hadron transition. We give transfer functions for cosmological density fluctuations that are useful for N-body simulations. We also provide a public code for the production calculation. In the second part of the thesis, we study the instability of small-scale baryon pressure sound waves during cosmological recombination. We show that for relevant wavenumbers, inhomogenous recombination is driven by the transport of ionizing continuum and Lyman-alpha photons. We find a maximum growth factor less than ≈ 1.2 in 107 random realizations of initial conditions. The low growth factors are due to the relatively short duration of the recombination epoch. In the third part of the thesis, we propose a method of measuring weak magnetic fields, of order 10--19 G (or 10--21 G if scaled to the present day), with large coherence lengths in the inter galactic medium prior to and during the epoch of cosmic reionization. The method utilizes the Larmor precession of spin-polarized neutral hydrogen in the triplet state of the hyperfine transition. We perform detailed calculations of the microphysics behind this effect, and take into account all the processes that affect the hyperfine transition, including radiative decays, collisions, and optical pumping by Lyman-alpha photons. In the final part of

  9. Strongly-Heated Gas Flow in Parallel Tube Rotation

    Directory of Open Access Journals (Sweden)

    Shuichi Torii

    1998-01-01

    Full Text Available A numerical analysis is performed to study thermal transport phenomena in gas flow through a strongly heated tube whose axis is in parallel with the rotational axis. The velocity and temperature fields prevail when fluid flows in a rotating tube with uniform heat flux on the tube wall. The two-equation k-ω turbulence and t2¯-εt heat transfer models are employed to determine turbulent viscosity and eddy diffusivity for heat, respectively. The governing boundary-layer equations are discritized by means of a control volume finitedifference techniques. It is found that the Coriolis and centrifugal (or centripetal forces cause fluid flow and heat transfer performance in the parallel-rotation system to be drastically different from those in the stationary case. Consequently, even if a tube rotating around a parallel axis is heated with high heat flux whose level causes a laminarizing flow in the stationary tube case, both the turbulent kinetic energy and the temperature variance remain over the pipe cross section, resulting in the suppression of an attenuation in heat transfer performance. In other words, an increase in tube rotation suppresses laminarization of gas flow.

  10. ''Strong gammas''. List of strong gamma-rays emitted from radionuclides. Documentation of the PC diskette

    International Nuclear Information System (INIS)

    Ichimiya, T.; Narita, T.; Kitao, K.

    1994-01-01

    The PC diskette containing the ''List of strong gamma-rays emitted from radionuclides'' as published by T. Narita et al. in the report JAERI-M-94-059, March 1994, is described. The diskette is available from the IAEA Nuclear Data Section, costfree, upon request. (author)

  11. Strong Feller solutions to SPDEďs are strong Feller in the weak topology

    Czech Academy of Sciences Publication Activity Database

    Maslowski, Bohdan; Seidler, Jan

    2001-01-01

    Roč. 148, č. 2 (2001), s. 111-129 ISSN 0039-3223 R&D Projects: GA ČR GA201/98/1454 Keywords : strong Feller property% stochastic parabolic equations Subject RIV: BA - General Mathematics Impact factor: 0.399, year: 2001

  12. Strong-field ionization of polar molecules: Stark-shift-corrected strong-field approximation

    DEFF Research Database (Denmark)

    Dimitrovski, Darko; Martiny, Christian P. J.; Madsen, Lars Bojer

    2010-01-01

    We extend the molecular strong-field approximation for ionization, in the tunneling limit, to include systematically the linear and quadratic static Stark shifts of the ionizing molecular orbital. This approach, simple to implement, is capable of describing the essential physics of the process of...

  13. Transportation of Dangerous Goods in Green Transport Corridors - Conclusions from Baltic Sea Region

    Directory of Open Access Journals (Sweden)

    Schröder Meike

    2016-12-01

    Full Text Available The Green Corridor concept represents a cornerstone in the development and implementation of integrated and sustainable transport solutions based on trans-nationality, multi-modality and a high involvement of public and private stakeholders, including the political level. Despite the fact that the Green Transport Corridor (GTC concept is founded on the three dimensions of sustainability with a strong emphasis on environmental aspects, the corridor hubs as well as the whole transport corridors have to find ways to handle and transport dangerous goods by keeping the high sustainability standards.

  14. Advanced Transportation Institute 2009.

    Science.gov (United States)

    2009-09-01

    The eighth version of the Advanced Transportation Institute (ATI-09) was conducted in 2009 to encourage high school students to pursue careers in the field of transportation engineering. The University Transportation Center for Alabama partnered with...

  15. State transportation statistics 2009

    Science.gov (United States)

    2009-01-01

    The Bureau of Transportation Statistics (BTS), a part of DOTs Research and Innovative Technology Administration (RITA), presents State Transportation Statistics 2009, a statistical profile of transportation in the 50 states and the District of Col...

  16. Strong quantum memory at resonant Fermi edges revealed by shot noise.

    Science.gov (United States)

    Ubbelohde, N; Roszak, K; Hohls, F; Maire, N; Haug, R J; Novotný, T

    2012-01-01

    Studies of non-equilibrium current fluctuations enable assessing correlations involved in quantum transport through nanoscale conductors. They provide additional information to the mean current on charge statistics and the presence of coherence, dissipation, disorder, or entanglement. Shot noise, being a temporal integral of the current autocorrelation function, reveals dynamical information. In particular, it detects presence of non-Markovian dynamics, i.e., memory, within open systems, which has been subject of many current theoretical studies. We report on low-temperature shot noise measurements of electronic transport through InAs quantum dots in the Fermi-edge singularity regime and show that it exhibits strong memory effects caused by quantum correlations between the dot and fermionic reservoirs. Our work, apart from addressing noise in archetypical strongly correlated system of prime interest, discloses generic quantum dynamical mechanism occurring at interacting resonant Fermi edges.

  17. Journal of transportation engineering

    National Research Council Canada - National Science Library

    1983-01-01

    The Journal of Transportation Engineering contains technical and professional articles on the planning, design, construction, maintenance, and operation of air, highway, rail, and urban transportation...

  18. Saxton Transportation Operations Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — The Saxton Transportation Operations Laboratory (Saxton Laboratory) is a state-of-the-art facility for conducting transportation operations research. The laboratory...

  19. Smart Growth and Transportation

    Science.gov (United States)

    Describes the relationship between smart growth and transportation, focusing smart and sustainable street design, transit-oriented development, parking management, sustainable transportation planning, and related resources.

  20. Transport corridors and settlements in a region. Linking settlements to public transport

    Directory of Open Access Journals (Sweden)

    Mojca Šašek Divjak

    2004-01-01

    Full Text Available The focus of the article is conditioning settlement to public transport on the regional and urban level. Similar to occurrences in Western Europe even in Slovenia strong settlement pressures and issues tied to development of suburbanisation are emerging in wider hinterlands of larger cities. In regional centres, where strong transport flows with frequent congestion happen, public transport should be the backbone of the transport system. It is important for consolidation of larger gravitation areas, especially conurbations. We can nevertheless establish that parallel to increasing use of private cars, the use of public transport is decreasing. Thus the present condition demands improvements of transport systems and suitable settlement density in conjunction with development of public transport. This can be achieved only by synergetic linking of public transport development and physical planning in a sustainable settlement system. In the Ljubljana functional region we specifically dealt with links between settlement and the regional public transport system, above all the proposed regional light-railway and tram system in the strict urban area. The decentralised denser settlement model is presented. Based on the study concerning settlement development in the railway corridors we proposed potential possibilities for denser settlement in the immediate areas of suburban railway stations in the northern part of the region, from Črnuče to Kamnik.

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

    International Nuclear Information System (INIS)

    FISCHER, W.; BLASKIEWICZ, M.; BRENNAN, J.M.; CAMERON, P.; CONNOLLY, R.; MONTAG, C.; PEGGS, S.; PILAT, F.; PTITSYN, V.; TEPIKIAN, S.; TRBOJEVIC, D.; VAN ZEIJTS, J.

    2003-01-01

    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. Strong earthquakes can be predicted: a multidisciplinary method for strong earthquake prediction

    Directory of Open Access Journals (Sweden)

    J. Z. Li

    2003-01-01

    Full Text Available The imminent prediction on a group of strong earthquakes that occurred in Xinjiang, China in April 1997 is introduced in detail. The prediction was made on the basis of comprehensive analyses on the results obtained by multiple innovative methods including measurements of crustal stress, observation of infrasonic wave in an ultra low frequency range, and recording of abnormal behavior of certain animals. Other successful examples of prediction are also enumerated. The statistics shows that above 40% of 20 total predictions jointly presented by J. Z. Li, Z. Q. Ren and others since 1995 can be regarded as effective. With the above methods, precursors of almost every strong earthquake around the world that occurred in recent years were recorded in our laboratory. However, the physical mechanisms of the observed precursors are yet impossible to explain at this stage.

  3. Strong Convergence for Hybrid Implicit S-Iteration Scheme of Nonexpansive and Strongly Pseudocontractive Mappings

    Directory of Open Access Journals (Sweden)

    Shin Min Kang

    2014-01-01

    Full Text Available Let K be a nonempty closed convex subset of a real Banach space E, let S:K→K be nonexpansive, and let  T:K→K be Lipschitz strongly pseudocontractive mappings such that p∈FS∩FT=x∈K:Sx=Tx=x and x-Sy≤Sx-Sy and x-Ty≤Tx-Ty for all x, y∈K. Let βn be a sequence in 0, 1 satisfying (i ∑n=1∞βn=∞; (ii limn→∞⁡βn=0. For arbitrary x0∈K, let xn be a sequence iteratively defined by xn=Syn, yn=1-βnxn-1+βnTxn, n≥1. Then the sequence xn converges strongly to a common fixed point p of S and T.

  4. Inhomogeneities in a strongly correlated d-wave superconductors in the limit of strong disorder

    Science.gov (United States)

    Chakraborty, Debmalya; Sensarma, Rajdeep; Ghosal, Amit

    2015-03-01

    The complex interplay of the strong correlations and impurities in a high temperature superconductor is analyzed within a Hartree-Fock-Bogoliubov theory, augmented with Gutzwiller approximation for taking care of the strong electronic repulsion. The inclusion of such correlations is found to play a crucial role in reducing inhomogeneities in both qualitative and quantitative manner. This difference is comprehended by investigating the underlying one-particle ``normal states'' that includes the order parameters in the Hartree and Fock channels in the absence of superconductivity. This amounts to the renormalization of disorder both on the lattice sites and also on links. These two components of disorder turn out to be spatially anti-correlated through self-consistency. Interestingly, a simple pairing theory in terms of these normal states is found to describe the complex behaviors of dirty cuprates with reasonable accuracy. However, this framework needs modifications in the limit where disorder strengths are comparable to the band width. We will discuss appropriate updates in the formalism to describe physics of inhomogeneities with strong disorder.

  5. Three points of view in transport theory

    Energy Technology Data Exchange (ETDEWEB)

    Ruben, Panta Pazos [Faculdade de Matematica, PUCRS, Porto Alegre, RS (Brazil); Tilio de Vilhena, M. [Instituto de Matematica, UFRGS, Porto Alegre, RS (Brazil)

    2001-07-01

    A lot of efforts in Transport Theory is used to develop numerical methods or hybrid numerical-analytical techniques. We present in this work three points of view about transport problems. First the C0 semigroup approach, in which the free transport operator {psi} {yields} {mu} {nabla} generates an strongly continuous semigroup. The operators operator {psi} {yields} {sigma}t and operator {psi} {yields} {integral} {nabla} k(x,{mu},{mu}') {psi}(x,{mu}') d{mu}' are bounded operators, and by perturbation the transport operator {psi} {yields} {mu} {nabla} {psi} + {sigma}t {psi} - K {psi} also generates an strongly continuous semigroup. To prove the convergence of the approximations of a numerical methods to the exact solution we use the approximation theorem of C0 semi-groups in canonical form. In other way, the discrete schemes theory is employed in searching the rate of convergence of numerical techniques in transport theory. For 1D dependent of time transport problem and two-dimensional steady state problem we summarize some estimates, incorporating different boundary conditions. Finally we give a survey about the dynamical behavior of the SN approximations. In order to give a unified approach, some results illustrates the equivalence of the three points of views for the case of the steady-state transport problem for slab geometry. (author)

  6. Three points of view in transport theory

    International Nuclear Information System (INIS)

    Ruben, Panta Pazos; Tilio de Vilhena, M.

    2001-01-01

    A lot of efforts in Transport Theory is used to develop numerical methods or hybrid numerical-analytical techniques. We present in this work three points of view about transport problems. First the C0 semigroup approach, in which the free transport operator ψ → μ ∇ generates an strongly continuous semigroup. The operators operator ψ → σt and operator ψ → ∫ ∇ k(x,μ,μ' ψ(x,μ') dμ' are bounded operators, and by perturbation the transport operator ψ → μ ∇ ψ + σt ψ - K ψ also generates an strongly continuous semigroup. To prove the convergence of the approximations of a numerical methods to the exact solution we use the approximation theorem of C0 semi-groups in canonical form. In other way, the discrete schemes theory is employed in searching the rate of convergence of numerical techniques in transport theory. For 1D dependent of time transport problem and two-dimensional steady state problem we summarize some estimates, incorporating different boundary conditions. Finally we give a survey about the dynamical behavior of the SN approximations. In order to give a unified approach, some results illustrates the equivalence of the three points of views for the case of the steady-state transport problem for slab geometry. (author)

  7. Influence of transport variables on isospin transport ratios

    International Nuclear Information System (INIS)

    Coupland, D. D. S.; Lynch, W. G.; Tsang, M. B.; Danielewicz, P.; Zhang Yingxun

    2011-01-01

    The symmetry energy in the nuclear equation of state affects many aspects of nuclear astrophysics, nuclear structure, and nuclear reactions. Recent constraints from heavy-ion collisions, including isospin diffusion observables, have started to put constraints on the symmetry energy below nuclear saturation density, but these constraints depend on the employed transport model and input physics other than the symmetry energy. To understand these dependencies, we study the influence of the symmetry energy, isoscalar mean-field compressibility and momentum dependence, in-medium nucleon-nucleon cross sections, and light cluster production on isospin diffusion within the pBUU transport code. In addition to the symmetry energy, several uncertain issues strongly affect isospin diffusion, most notably the cross sections and cluster production. In addition, there is a difference in the calculated isospin transport ratios, depending on whether they are computed using the isospin asymmetry either of the residue or of all forward-moving fragments. Measurements that compare the isospin transport ratios of these two quantities would help place constraints on the input physics, such as the density dependence of the symmetry energy.

  8. Influence of transport variables on isospin transport ratios

    Science.gov (United States)

    Coupland, D. D. S.; Lynch, W. G.; Tsang, M. B.; Danielewicz, P.; Zhang, Yingxun

    2011-11-01

    The symmetry energy in the nuclear equation of state affects many aspects of nuclear astrophysics, nuclear structure, and nuclear reactions. Recent constraints from heavy-ion collisions, including isospin diffusion observables, have started to put constraints on the symmetry energy below nuclear saturation density, but these constraints depend on the employed transport model and input physics other than the symmetry energy. To understand these dependencies, we study the influence of the symmetry energy, isoscalar mean-field compressibility and momentum dependence, in-medium nucleon-nucleon cross sections, and light cluster production on isospin diffusion within the pBUU transport code. In addition to the symmetry energy, several uncertain issues strongly affect isospin diffusion, most notably the cross sections and cluster production. In addition, there is a difference in the calculated isospin transport ratios, depending on whether they are computed using the isospin asymmetry either of the residue or of all forward-moving fragments. Measurements that compare the isospin transport ratios of these two quantities would help place constraints on the input physics, such as the density dependence of the symmetry energy.

  9. Do freight transport time savings translate to benefit for transport consuming companies?

    Directory of Open Access Journals (Sweden)

    Evangelos Sambracos

    2017-05-01

    Full Text Available It is common practice in Benefit - Cost analysis to consider freight transport time savings (FTTS as a benefit for both transport producing and consuming companies. While transportation projects and policies resulting in FTTS are expected to have a positive effect on carriers’ performance reducing time related transport costs and improving service, this is not always the case for the demand side of the transport market. Using System Dynamics in order to model the internal supply chain of a transport using company and simulate several scenarios, we argue that FTTS do not necessarily translate to benefit for shippers, but their effect depends strongly on the structure of the company’s decision making process.

  10. Ionosphere TEC disturbances before strong earthquakes: observations, physics, modeling (Invited)

    Science.gov (United States)

    Namgaladze, A. A.

    2013-12-01

    The phenomenon of the pre-earthquake ionospheric disturbances is discussed. A number of typical TEC (Total Electron Content) relative disturbances is presented for several recent strong earthquakes occurred in different ionospheric conditions. Stable typical TEC deviations from quiet background state are observed few days before the strong seismic events in the vicinity of the earthquake epicenter and treated as ionospheric earthquake precursors. They don't move away from the source in contrast to the disturbances related with geomagnetic activity. Sunlit ionosphere approach leads to reduction of the disturbances up to their full disappearance, and effects regenerate at night. The TEC disturbances often observed in the magnetically conjugated areas as well. At low latitudes they accompany with equatorial anomaly modifications. The hypothesis about the electromagnetic channel of the pre-earthquake ionospheric disturbances' creation is discussed. The lithosphere and ionosphere are coupled by the vertical external electric currents as a result of ionization of the near-Earth air layer and vertical transport of the charged particles through the atmosphere over the fault. The external electric current densities exceeding the regular fair-weather electric currents by several orders are required to produce stable long-living seismogenic electric fields such as observed by onboard measurements of the 'Intercosmos-Bulgaria 1300' satellite over the seismic active zones. The numerical calculation results using the Upper Atmosphere Model demonstrate the ability of the external electric currents with the densities of 10-8-10-9 A/m2 to produce such electric fields. The sumulations reproduce the basic features of typical pre-earthquake TEC relative disturbances. It is shown that the plasma ExB drift under the action of the seismogenic electric field leads to the changes of the F2 region electron number density and TEC. The upward drift velocity component enhances NmF2 and TEC and

  11. Big, strong, neutral, twisted, and chiral π acids.

    Science.gov (United States)

    Zhao, Yingjie; Huang, Guangxi; Besnard, Celine; Mareda, Jiri; Sakai, Naomi; Matile, Stefan

    2015-04-13

    General synthetic access to expanded π-acidic surfaces of variable size, topology, chirality, and π acidity is reported. The availability of π surfaces with these characteristics is essential to develop the functional relevance of anion-π interactions with regard to molecular recognition, translocation, and transformation. The problem is that, with expanded π surfaces, the impact of electron-withdrawing substituents decreases and the high π acidity needed for strong anion-π interactions can be more difficult to obtain. To overcome this problem, it is herein proposed to build large surfaces from smaller fragments and connect these fragments with bridges that are composed only of single atoms. Two central surfaces for powerful anion-π interactions, namely, perfluoroarenes and naphthalenediimides (NDIs), were selected as fragments and coupled with through sulfide bridges. Their oxidation to sulfoxides and sulfones, as well as fluorine substitution in the peripheral rings, provides access to the full chemical space of relevant π acidities. According to cyclic voltammetry, LUMO levels range from -3.96 to -4.72 eV. With sulfoxide bridges, stereogenic centers are introduced to further enrich the intrinsic planar chirality of the expanded surfaces. The stereoisomers were separated by chiral HPLC and characterized by X-ray crystallography. Their topologies range from chairs to π boats, and the latter are reminiscent of the cation-π boxes in operational neuronal receptors. With pentafluorophenyl acceptors, the π acidity of NDIs with two sulfoxide groups in the core reaches -4.45 eV, whereas two sulfone moieties give a value of -4.72 eV, which is as low as with four ethyl sulfone groups, that is, a π superacid near the limit of existence. Beyond anion-π interactions, these conceptually innovative π-acidic surfaces are also of interest as electron transporters in conductive materials. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Water-transporting proteins

    DEFF Research Database (Denmark)

    Zeuthen, Thomas

    2010-01-01

    . In the K(+)/Cl(-) and the Na(+)/K(+)/2Cl(-) cotransporters, water is entirely cotransported, while water transport in glucose uniporters and Na(+)-coupled transporters of nutrients and neurotransmitters takes place by both osmosis and cotransport. The molecular mechanism behind cotransport of water...... transport. Epithelial water transport is energized by the movements of ions, but how the coupling takes place is uncertain. All epithelia can transport water uphill against an osmotic gradient, which is hard to explain by simple osmosis. Furthermore, genetic removal of aquaporins has not given support...... to osmosis as the exclusive mode of transport. Water cotransport can explain the coupling between ion and water transport, a major fraction of transepithelial water transport and uphill water transport. Aquaporins enhance water transport by utilizing osmotic gradients and cause the osmolarity...

  13. Triad pattern algorithm for predicting strong promoter candidates in bacterial genomes

    Directory of Open Access Journals (Sweden)

    Sakanyan Vehary

    2008-05-01

    Full Text Available Abstract Background Bacterial promoters, which increase the efficiency of gene expression, differ from other promoters by several characteristics. This difference, not yet widely exploited in bioinformatics, looks promising for the development of relevant computational tools to search for strong promoters in bacterial genomes. Results We describe a new triad pattern algorithm that predicts strong promoter candidates in annotated bacterial genomes by matching specific patterns for the group I σ70 factors of Escherichia coli RNA polymerase. It detects promoter-specific motifs by consecutively matching three patterns, consisting of an UP-element, required for interaction with the α subunit, and then optimally-separated patterns of -35 and -10 boxes, required for interaction with the σ70 subunit of RNA polymerase. Analysis of 43 bacterial genomes revealed that the frequency of candidate sequences depends on the A+T content of the DNA under examination. The accuracy of in silico prediction was experimentally validated for the genome of a hyperthermophilic bacterium, Thermotoga maritima, by applying a cell-free expression assay using the predicted strong promoters. In this organism, the strong promoters govern genes for translation, energy metabolism, transport, cell movement, and other as-yet unidentified functions. Conclusion The triad pattern algorithm developed for predicting strong bacterial promoters is well suited for analyzing bacterial genomes with an A+T content of less than 62%. This computational tool opens new prospects for investigating global gene expression, and individual strong promoters in bacteria of medical and/or economic significance.

  14. Transport processes at fluidic interfaces

    CERN Document Server

    Reusken, Arnold

    2017-01-01

    There are several physico-chemical processes that determine the behavior of multiphase fluid systems – e.g., the fluid dynamics in the different phases and the dynamics of the interface(s), mass transport between the fluids, adsorption effects at the interface, and transport of surfactants on the interface – and result in heterogeneous interface properties. In general, these processes are strongly coupled and local properties of the interface play a crucial role. A thorough understanding of the behavior of such complex flow problems must be based on physically sound mathematical models, which especially account for the local processes at the interface. This book presents recent findings on the rigorous derivation and mathematical analysis of such models and on the development of numerical methods for direct numerical simulations. Validation results are based on specifically designed experiments using high-resolution experimental techniques. A special feature of this book is its focus on an interdisciplina...

  15. Quantum transport in carbon nanotubes

    DEFF Research Database (Denmark)

    Laird, Edward A.; Kuemmeth, Ferdinand; Steele, Gary A.

    2015-01-01

    Carbon nanotubes are a versatile material in which many aspects of condensed matter physics come together. Recent discoveries, enabled by sophisticated fabrication, have uncovered new phenomena that completely change our understanding of transport in these devices, especially the role of the spin...... blockade. This can be exploited to read out spin and valley qubits, and to measure the decay of these states through coupling to nuclear spins and phonons. A second unique property of carbon nanotubes is that the combination of valley freedom and electron-electron interactions in one dimension strongly...... and valley degrees of freedom. This review describes the modern understanding of transport through nanotube devices. Unlike conventional semiconductors, electrons in nanotubes have two angular momentum quantum numbers, arising from spin and from valley freedom. We focus on the interplay between the two...

  16. Modelling of Transport Phenomena

    OpenAIRE

    K., Itoh; S.-I., Itoh; A., Fukuyama

    1993-01-01

    In this review article, we discuss key features of the transport phenomena and theoretical modelling to understand them. Experimental observations have revealed the nature of anomalous transport, i.e., the enhancement of the transport coefficients by the gradients of the plasma profiles, the pinch phenomena, the radial profile of the apomalous transport coefficients, the variation of the transport among the Bohm diffusion, Pseudo-classical confinement, L-mode and variety of improved confineme...

  17. Evaluation of public transport in selected Slovenian municipalities

    Directory of Open Access Journals (Sweden)

    Matej Ogrin

    2014-12-01

    Full Text Available In Slovenia public transport is in decline already for few decades. At the same time, the country faces a strong growth of motorisation. Its growth was even stronger than in most of EU countries, which resulted that Slovenian transport system is very expensive, it causes excessive air pollution and is far from sustainable. However, in some cities and areas in last years we can notice some signs of public transport recovery. The article compares public transport systems in selected Slovenian municipalities and shows which measures were taken to implement recovery of transport systems.

  18. Anomalous transport effects and possible environmental symmetry ...

    Indian Academy of Sciences (India)

    2015-05-06

    May 6, 2015 ... The heavy-ion collision provides a unique many-body environment where local domains of strongly interacting chiral medium may occur and in a sense allow environmental symmetry 'violation' phenomena. For example, certain anomalous transport processes, forbidden in usual medium, become possible ...

  19. Magnetic type transportation system

    International Nuclear Information System (INIS)

    Kobama, Masao.

    1981-01-01

    Purpose: To enable automatic transportation of nuclear substances with optional setting for the transportation distance, even for a long distance, facilitating the automation of the transportation and decreasing the space for the installation of a direction converging section of the transporting path. Constitution: A transporting vehicle having a pair of permanent magnets or ferromagnetic bodies mounted with a predetermined gap to each other along the transporting direction is provided in the transporting path including a bent direction change section for transporting specimens such as nuclear materials, and a plurality of driving vehicles having permanent magnets or ferromagnetic bodies for magnetically attracting the transporting vehicle from outside of the transporting path are arranged to the outside of the transporting path. At least one of the driving vehicles is made to run along the transporting direction of the transporting path by a driving mechanism incorporating running section such as an endless chain to drive the transportation vehicle, and the transporting vehicle is successively driven by each of the driving mechanisms. (Kawakami, Y.)

  20. Transport experiments with Dirac electrons

    Science.gov (United States)

    Checkelsky, Joseph George

    This thesis presents transport experiments performed on solid state systems in which the behavior of the charge carriers can be described by the Dirac equation. Unlike the massive carriers in a typical material, in these systems the carriers behave like massless fermions with a photon-like dispersion predicted to greatly modify their spin and charge transport properties. The first system studied is graphene, a crystalline monolayer of carbon arranged in a hexagonal lattice. The band structure calculated from the hexagonal lattice has the form of the massless Dirac Hamiltonian. At the charge neutral Dirac point, we find that application of a magnetic field drives a transition to an insulating state. We also study the thermoelectric properties of graphene and find that the states near the Dirac point have a unique response compared to those at higher charge density. The second system is the 3D topological insulator Bi2Se3, where a Dirac-like dispersion for states on the 2D surface of the insulating 3D crystal arises as a result of the topology of the 3D bands and time reversal symmetry. To access the transport properties of the 2D states, we suppress the remnant bulk conduction channel by chemical doping and electrostatic gating. In bulk crystals we find strong quantum corrections to transport at low temperature when the bulk conduction channel is maximally suppressed. In microscopic crystals we are able better to isolate the surface conduction channel properties. We identify in-gap conducting states that have relatively high mobility compared to the bulk and exhibit weak anti-localization, consistent with predictions for protected 2D surface states with strong spin-orbit coupling.