Effective quantum dynamics of interacting systems with inhomogeneous coupling
Lopez, C. E.; Retamal, J. C.; Christ, H.; Solano, E.
2007-03-15
We study the quantum dynamics of a single mode (particle) interacting inhomogeneously with a large number of particles and introduce an effective approach to find the accessible Hilbert space, where the dynamics takes place. Two relevant examples are given: the inhomogeneous Tavis-Cummings model (e.g., N atomic qubits coupled to a single cavity mode, or to a motional mode in trapped ions) and the inhomogeneous coupling of an electron spin to N nuclear spins in a quantum dot.
Coupled effects of local movement and global interaction on contagion
NASA Astrophysics Data System (ADS)
Zhong, Li-Xin; Xu, Wen-Juan; Chen, Rong-Da; Qiu, Tian; Shi, Yong-Dong; Zhong, Chen-Yang
2015-10-01
By incorporating segregated spatial domain and individual-based linkage into the SIS (susceptible-infected-susceptible) model, we propose a generalized epidemic model which can change from the territorial epidemic model to the networked epidemic model. The role of the individual-based linkage between different spatial domains is investigated. As we adjust the timescale parameter τ from 0 to unity, which represents the degree of activation of the individual-based linkage, three regions are found. Within the region of 0 < τ < 0.02, the epidemic is determined by local movement and is sensitive to the timescale τ. Within the region of 0.02 < τ < 0.5, the epidemic is insensitive to the timescale τ. Within the region of 0.5 < τ < 1, the outbreak of the epidemic is determined by the structure of the individual-based linkage. As we keep an eye on the first region, the role of activating the individual-based linkage in the present model is similar to the role of the shortcuts in the two-dimensional small world network. Only activating a small number of the individual-based linkage can prompt the outbreak of the epidemic globally. The role of narrowing segregated spatial domain and reducing mobility in epidemic control is checked. These two measures are found to be conducive to curbing the spread of infectious disease only when the global interaction is suppressed. A log-log relation between the change in the number of infected individuals and the timescale τ is found. By calculating the epidemic threshold and the mean first encounter time, we heuristically analyze the microscopic characteristics of the propagation of the epidemic in the present model.
Hartley, Sigan L; Papp, Lauren M; Blumenstock, Shari M; Floyd, Frank; Goetz, Greta L
2016-09-01
The vulnerability-stress-adaptation model guided this examination of the impact of daily fluctuations in the symptoms and co-occurring behavior problems of children with autism spectrum disorder (ASD) on parents' couple problem-solving interactions in natural settings and as these interactions spontaneously occur. A 14-day daily diary was completed by mothers and fathers in 176 families who had a child with ASD. On each day of the diary, parents separately reported on the child with ASD's daily level of symptoms and co-occurring behavior problems and the topic and level of negative affect in their most meaningful or important daily couple problem-solving interaction. Multilevel modeling was used to account for the within-person, within-couple nested structure of the data. Results indicated that many parents are resilient to experiencing a day with a high level of child ASD symptoms and co-occurring behavior problems and do not report more negative couple problem-solving interactions. However, household income, level of parental broader autism phenotype, and presence of multiple children with special care needs served as vulnerability factors in that they were related to a higher overall rating of negative affect in couple interactions and moderated the impact of reporting a day with a high level of child ASD symptoms and co-occurring behavior problems on next-day ratings of negative couple problem-solving interactions. The magnitude of these effects was small. Understanding mechanisms that support adaptive couple interactions in parents of children with ASD is critical for promoting best outcomes. (PsycINFO Database Record
Hartley, Sigan L; Papp, Lauren M; Blumenstock, Shari M; Floyd, Frank; Goetz, Greta L
2016-09-01
The vulnerability-stress-adaptation model guided this examination of the impact of daily fluctuations in the symptoms and co-occurring behavior problems of children with autism spectrum disorder (ASD) on parents' couple problem-solving interactions in natural settings and as these interactions spontaneously occur. A 14-day daily diary was completed by mothers and fathers in 176 families who had a child with ASD. On each day of the diary, parents separately reported on the child with ASD's daily level of symptoms and co-occurring behavior problems and the topic and level of negative affect in their most meaningful or important daily couple problem-solving interaction. Multilevel modeling was used to account for the within-person, within-couple nested structure of the data. Results indicated that many parents are resilient to experiencing a day with a high level of child ASD symptoms and co-occurring behavior problems and do not report more negative couple problem-solving interactions. However, household income, level of parental broader autism phenotype, and presence of multiple children with special care needs served as vulnerability factors in that they were related to a higher overall rating of negative affect in couple interactions and moderated the impact of reporting a day with a high level of child ASD symptoms and co-occurring behavior problems on next-day ratings of negative couple problem-solving interactions. The magnitude of these effects was small. Understanding mechanisms that support adaptive couple interactions in parents of children with ASD is critical for promoting best outcomes. (PsycINFO Database Record PMID:27336179
Baalrud, Scott D.; Daligault, Jérôme
2014-05-15
A method for extending traditional plasma transport theories into the strong coupling regime is presented. Like traditional theories, this is based on a binary scattering approximation, but where physics associated with many body correlations is included through the use of an effective interaction potential. The latter is simply related to the pair-distribution function. Modeling many body effects in this manner can extend traditional plasma theory to orders of magnitude stronger coupling. Theoretical predictions are tested against molecular dynamics simulations for electron-ion temperature relaxation as well as diffusion in one component systems. Emphasis is placed on the connection with traditional plasma theory, where it is stressed that the effective potential concept has precedence through the manner in which screening is imposed. The extension to strong coupling requires accounting for correlations in addition to screening. Limitations of this approach in the presence of strong caging are also discussed.
Behnia, Behnoush; Heinrichs, Markus; Bergmann, Wiebke; Jung, Stefanie; Germann, Janine; Schedlowski, Manfred; Hartmann, Uwe; Kruger, Tillmann H C
2014-03-01
Knowledge about the effects of the neuropeptide oxytocin (OXT) on human sexual behaviors and partner interactions remains limited. Based on our previous studies, we hypothesize that OXT should be able to positively influence parameters of sexual function and couple interactions. Employing a naturalistic setting involving 29 healthy heterosexual couples (n=58 participants), we analyzed the acute effects of intranasally administered OXT (24IU) on sexual drive, arousal, orgasm and refractory aspects of sexual behavior together with partner interactions. Data were assessed by psychometric instruments (Acute Sexual Experiences Scale, Arizona Sexual Experience Scale) as well as biomarkers, such as cortisol, α-amylase and heart rate. Intranasal OXT administration did not alter "classical" parameters of sexual function, such as sexual drive, arousal or penile erection and lubrication. However, analysis of variance and a hierarchical linear model (HLM) revealed specific effects related to the orgasmic/post-orgasmic interval as well as parameters of partner interactions. According to HLM analysis, OXT increased the intensity of orgasm, contentment after sexual intercourse and the effect of study participation. According to ANOVA analysis, these effects were more pronounced in men. Men additionally indicated higher levels of sexual satiety after sexual intercourse with OXT administration. Women felt more relaxed and subgroups indicated better abilities to share sexual desires or to empathize with their partners. The effect sizes were small to moderate. Biomarkers indicated moderate psychophysiological activation but were not affected by OXT, gender or method of contraception. Using a naturalistic setting, intranasal OXT administration in couples exerted differential effects on parameters of sexual function and partner interactions. These results warrant further investigations, including subjects with sexual and relationship problems.
NASA Astrophysics Data System (ADS)
Audus, Debra J.; Starr, Francis W.; Douglas, Jack F.
2016-02-01
The interactions of molecules and particles in solution often involve an interplay between isotropic and highly directional interactions that lead to a mutual coupling of phase separation and self-assembly. This situation arises, for example, in proteins interacting through hydrophobic and charged patch regions on their surface and in nanoparticles with grafted polymer chains, such as DNA. As a minimal model of complex fluids exhibiting this interaction coupling, we investigate spherical particles having an isotropic interaction and a constellation of five attractive patches on the particle's surface. Monte Carlo simulations and mean-field calculations of the phase boundaries of this model depend strongly on the relative strength of the isotropic and patch potentials, where we surprisingly find that analytic mean-field predictions become increasingly accurate as the directional interactions become increasingly predominant. We quantitatively account for this effect by noting that the effective interaction range increases with increasing relative directional to isotropic interaction strength. We also identify thermodynamic transition lines associated with self-assembly, extract the entropy and energy of association, and characterize the resulting cluster properties obtained from simulations using percolation scaling theory and Flory-Stockmayer mean-field theory. We find that the fractal dimension and cluster size distribution are consistent with those of lattice animals, i.e., randomly branched polymers swollen by excluded volume interactions. We also identify a universal functional form for the average molecular weight and a nearly universal functional form for a scaling parameter characterizing the cluster size distribution. Since the formation of branched clusters at equilibrium is a common phenomenon in nature, we detail how our analysis can be used in experimental characterization of such associating fluids.
Ghodrat, Malihe; Naji, Ali; Komaie-Moghaddam, Haniyeh; Podgornik, Rudolf
2015-05-01
We study the effective interaction mediated by strongly coupled Coulomb fluids between dielectric surfaces carrying quenched, random monopolar charges with equal mean and variance, both when the Coulomb fluid consists only of mobile multivalent counterions and when it consists of an asymmetric ionic mixture containing multivalent and monovalent (salt) ions in equilibrium with an aqueous bulk reservoir. We analyze the consequences that follow from the interplay between surface charge disorder, dielectric and salt image effects, and the strong electrostatic coupling that results from multivalent counterions on the distribution of these ions and the effective interaction pressure they mediate between the surfaces. In a dielectrically homogeneous system, we show that the multivalent counterions are attracted towards the surfaces with a singular, disorder-induced potential that diverges logarithmically on approach to the surfaces, creating a singular but integrable counterion density profile that exhibits an algebraic divergence at the surfaces with an exponent that depends on the surface charge (disorder) variance. This effect drives the system towards a state of lower thermal 'disorder', one that can be described by a renormalized temperature, exhibiting thus a remarkable antifragility. In the presence of an interfacial dielectric discontinuity, the singular behavior of counterion density at the surfaces is removed but multivalent counterions are still accumulated much more strongly close to randomly charged surfaces as compared with uniformly charged ones. The interaction pressure acting on the surfaces displays in general a highly non-monotonic behavior as a function of the inter-surface separation with a prominent regime of attraction at small to intermediate separations. This attraction is caused directly by the combined effects from charge disorder and strong coupling electrostatics of multivalent counterions, which dominate the surface-surface repulsion due to
Gittoes, Marianne J R; Kerwin, David G
2009-08-01
This study aimed to gain insight into the individual and interactive effects of segmental mass proportions and coupling properties on external loading in simulated forefoot landings. An evaluated four-segment wobbling mass model replicated forefoot drop landings (height: 0.46 m) performed by two subjects. A comparison of the peak impact forces (GFzmax) produced during the evaluated landing and further simulated landings performed using modified (+/-5% perturbation) mass proportions and coupling properties was made. Independent segmental mass proportion changes, particularly in the upper body, produced a prominent change in GFzmax of up to 0.32 bodyweight (BW) whereas independent mass coupling stiffness and damping alterations had less effect on GFzmax (change in GFzmax of up to 0.18 BW). When combining rigid mass proportion reductions with damping modifications, an additional GFzmax attenuation of up to 0.13 BW was produced. An individual may be predisposed to high loading and traumatic and overuse injury during forefoot landings owing to their inherent inertia profile. Subject-specific neuromuscular modifications to mass coupling properties may not be beneficial in overriding the increased forces associated with larger rigid mass proportions. PMID:19827473
Interaction effects on the tunneling of electron-hole pairs in coupled quantum dots
NASA Astrophysics Data System (ADS)
Guerrero, Hector M.; Cocoletzi, Gregorio H.; Ulloa, Sergio E.
2001-03-01
The transit time of carriers is beginning to be an important parameter in the physical operation of semiconductor quantum dot `devices'. In the present work, we study the coherent propagation of electron-hole pairs in coupled self-assembled quantum dots in close proximity. These systems, achieved experimentally in a number of different geometries, have been recently implemented as a novel storage of optical information that may give rise to smart pixel technology in the near future [1]. Here, we apply an effective mass hamiltonian approach and solve numerically the time dependent Schroedinger equation of a system of photo-created electron-hole pairs in the dots. Our approach takes into account both Coulomb interactions and confinement effects. The time evolution is investigated in terms of the structural parameters for typical InAs-GaAs dots. Different initial conditions are considered, reflecting the basic processes that would take place in these experiments. We study the probabilities of finding the electron and hole in either the same or adjacent quantum dot, and study carefully the role of interactions in this behavior. [1] T. Lundstrom, W. Schoenfeld, H. Lee, and P. M. Petroff, Science 286, 2312 (1999).
ERIC Educational Resources Information Center
Laurent, Heidemarie K.; Kim, Hyoun K.; Capaldi, Deborah M.
2008-01-01
This study tested associations among observed interaction patterns and relationship satisfaction in a subsample of young at-risk couples (n=47) from the Oregon Youth Study who remained stable over 7 years; each partner's positive engagement, psychological aggression, and withdrawal within a particular conflict structure (his vs. her topic) was…
Sexual Interaction in Nonclinical Couples.
ERIC Educational Resources Information Center
Woody, Jane D.; D'Souza, Henry J.
1997-01-01
Reports on the sexual functioning and interaction of 58 nonclinical heterosexual couples as measured by the Sexual Interaction System Scale (SISS). On all five SISS factors, the nonclinical sample scored significantly better than persons in therapy for sexual dysfunction; they also reported satisfactory relationship adjustment and high levels of…
Smith, Timothy W.; Uchino, Bert N.; MacKenzie, Justin; Hicks, Angela; Campo, Rebecca A.; Reblin, Maija; Grewen, Karen; Amico, Janet A.; Light, Kathleen C.
2016-01-01
Cardiovascular reactivity is a potential mechanism underlying associations of close relationship quality with cardiovascular disease. Two models describe oxytocin as another mechanism. The “calm and connect” model posits an association between positive relationship experiences and oxytocin levels and responses, whereas the “tend and befriend” model emphasizes the effects of negative relationship experiences in evoking oxytocin release. In this study of 180 younger couples, relationship quality had a small, marginally significant inverse association with plasma oxytocin levels, and neither positive nor negative couple interactions evoked change in plasma oxytocin. Negative couple interactions evoked significant cardiovascular reactivity, especially among women. Hence, in the largest study of these issues to date, there was little support for key tenets of the “calm and connect” model, and only very modest support for the ”tend and befriend” model. However, findings were consistent with the view that CVR contributes to the effects of relationship difficulties on health. PMID:22543270
Fluctuation-induced transport of two coupled particles: Effect of the interparticle interaction
NASA Astrophysics Data System (ADS)
Makhnovskii, Yurii A.; Rozenbaum, Viktor M.; Sheu, Sheh-Yi; Yang, Dah-Yen; Trakhtenberg, Leonid I.; Lin, Sheng Hsien
2014-06-01
We consider a system of two coupled particles fluctuating between two states, with different interparticle interaction potentials and particle friction coefficients. An external action drives the interstate transitions that induces reciprocating motion along the internal coordinate x (the interparticle distance). The system moves unidirectionally due to rectification of the internal motion by asymmetric friction fluctuations and thus operates as a dimeric motor that converts input energy into net movement. We focus on how the law of interaction between the particles affects the dimer transport and, in particular, the role of thermal noise in the motion inducing mechanism. It is argued that if the interaction potential behaves at large distances as xα, depending on the value of the exponent α, the thermal noise plays a constructive (α > 2), neutral (α = 2), or destructive (α < 2) role. In the case of α = 1, corresponding piecewise linear potential profiles, an exact solution is obtained and discussed in detail.
Ditzen, Beate; Neumann, Inga D; Bodenmann, Guy; von Dawans, Bernadette; Turner, Rebecca A; Ehlert, Ulrike; Heinrichs, Markus
2007-06-01
In animal studies, positive social interaction and physical contact play a preeminent role in the control of behavioral and neuroendocrine responses to stress. The aim of this study was to determine whether specific kinds of couple interaction reduce hypothalamic-pituitary-adrenal (HPA) and autonomic responses to psychosocial stress in women. Sixty-seven women, aged 20-37 years, who had been married or cohabiting with a male partner for at least 12 months at the time of the study, were exposed to a standardized psychosocial laboratory stressor (Trier Social Stress Test). Participants were randomly assigned to three study groups differing in the type of a 10-min period of social interaction with their partner prior to stress: n=25 with no partner interaction, n=22 with verbal social support, and n=20 with physical contact (standardized neck and shoulder massage). Salivary free cortisol levels, plasma levels of oxytocin, heart rate, and psychological responses to stress were compared among the three study groups. Women with positive physical partner contact before stress exhibited significantly lower cortisol and heart rate responses to stress but no different plasma oxytocin levels compared to women who received social support or no social interaction. Verbal social support alone was not associated with reduced stress responsiveness. Our results are in line with previous human studies indicating reduced responsiveness to verbal social support by a spouse in women. More importantly, these findings imply a direct protective effect of touch on stress-related neurobiological systems as a possible underlying mechanism of health beneficial effects of positive couple interaction.
NASA Astrophysics Data System (ADS)
Simon, Sven
2015-09-01
We develop a new analytical model of the Alfvén wing that is generated by the interaction between a planetary moon's ionosphere and its magnetospheric environment. While preceding analytical approaches assumed the obstacle's height-integrated ionospheric conductivities to be spatially constant, the model presented here can take into account a continuous conductance profile that follows a power law. The electric potential in the interaction region, determining the electromagnetic fields of the Alfvén wing, can then be calculated from an Euler-type differential equation. In this way, the model allows to include a realistic representation of the "suspension bridge"-like conductance profile expected for the moon's ionosphere. The major drawback of this approach is its restriction to interaction scenarios where the ionospheric Pedersen conductance is large compared to the Hall conductance, and thus, the Alfvénic perturbations are approximately symmetric between the planet-facing and the planet-averted hemispheres of the moon. The model is applied to the hemisphere coupling effect observed at Enceladus, i.e., to the surface currents and the associated magnetic discontinuities that arise from a north-south asymmetry of the obstacle to the plasma flow. We show that the occurrence of this effect is very robust against changes in the conductance profile of Enceladus' plume, and we derive upper limits for the strength of the magnetic field jumps generated by the hemisphere coupling effect. During all 11 reported detections of the hemisphere coupling currents at Enceladus, the observed magnetic field jumps were clearly weaker than the proposed limits. Our findings are also relevant for future in situ studies of putative plumes at the Jovian moon Europa.
NASA Astrophysics Data System (ADS)
Bangert, M.; Kottmeier, C.; Vogel, B.; Vogel, H.
2011-01-01
We have extended the coupled mesoscale atmosphere and chemistry model COSMO-ART to account for the transformation of aerosol particles into cloud condensation nuclei and to quantify their interaction with warm cloud microphysics on the regional scale. The new model system aims to fill the gap between cloud resolving models and global scale models. It represents the very complex microscale aerosol and cloud physics as detailed as possible, whereas the continental domain size and efficient codes will allow for both studying weather and regional climate. The model system is applied in a first extended case study for Europe for a cloudy five day period in August 2005. The model results show that the mean cloud droplet number concentration of clouds is correlated with the structure of the terrain, and we present a terrain slope parameter TS to classify this dependency. We propose to use this relationship to parameterise the PDF of subgrid-scale cloud updraft velocity in the activation parameterisations of climate models. The simulations show that the presence of CCN and clouds are closely related spatially. We find high aerosol and CCN number concentrations in the vicinity of clouds at high altitudes. The nucleation of secondary particles is enhanced above the clouds. This is caused by an efficient formation of gaseous aerosol precursors above the cloud due to more available radiation, transport of gases in clean air above the cloud, and humid conditions. Therefore the treatment of complex photochemistry is crucial in atmospheric models to simulate the distribution of CCN. The mean cloud droplet number concentration and droplet diameter showed a close link to the change in the aerosol. To quantify the net impact of an aerosol change on the precipitation we calculated the precipitation susceptibility β for the whole model domain over a period of two days with an hourly resolution. The distribution function of β is slightly skewed to positive values and has a mean of 0
NASA Astrophysics Data System (ADS)
Bangert, M.; Kottmeier, C.; Vogel, B.; Vogel, H.
2011-05-01
We have extended the coupled mesoscale atmosphere and chemistry model COSMO-ART to account for the transformation of aerosol particles into cloud condensation nuclei and to quantify their interaction with warm cloud microphysics on the regional scale. The new model system aims to fill the gap between cloud resolving models and global scale models. It represents the very complex microscale aerosol and cloud physics as detailed as possible, whereas the continental domain size and efficient codes will allow for both studying weather and regional climate. The model system is applied in a first extended case study for Europe for a cloudy five day period in August 2005. The model results show that the mean cloud droplet number concentration of clouds is correlated with the structure of the terrain, and we present a terrain slope parameter TS to classify this dependency. We propose to use this relationship to parameterize the probability density function, PDF, of subgrid-scale cloud updraft velocity in the activation parameterizations of climate models. The simulations show that the presence of cloud condensation nuclei (CCN) and clouds are closely related spatially. We find high aerosol and CCN number concentrations in the vicinity of clouds at high altitudes. The nucleation of secondary particles is enhanced above the clouds. This is caused by an efficient formation of gaseous aerosol precursors above the cloud due to more available radiation, transport of gases in clean air above the cloud, and humid conditions. Therefore the treatment of complex photochemistry is crucial in atmospheric models to simulate the distribution of CCN. The mean cloud droplet number concentration and droplet diameter showed a close link to the change in the aerosol. To quantify the net impact of an aerosol change on the precipitation we calculated the precipitation susceptibility β for the whole model domain over a period of two days with an hourly resolution. The distribution function of
Bessette, Gregory Carl
2004-09-01
Modeling the response of buried reinforced concrete structures subjected to close-in detonations of conventional high explosives poses a challenge for a number of reasons. Foremost, there is the potential for coupled interaction between the blast and structure. Coupling enters the problem whenever the structure deformation affects the stress state in the neighboring soil, which in turn, affects the loading on the structure. Additional challenges for numerical modeling include handling disparate degrees of material deformation encountered in the structure and surrounding soil, modeling the structure details (e.g., modeling the concrete with embedded reinforcement, jointed connections, etc.), providing adequate mesh resolution, and characterizing the soil response under blast loading. There are numerous numerical approaches for modeling this class of problem (e.g., coupled finite element/smooth particle hydrodynamics, arbitrary Lagrange-Eulerian methods, etc.). The focus of this work will be the use of a coupled Euler-Lagrange (CEL) solution approach. In particular, the development and application of a CEL capability within the Zapotec code is described. Zapotec links two production codes, CTH and Pronto3D. CTH, an Eulerian shock physics code, performs the Eulerian portion of the calculation, while Pronto3D, an explicit finite element code, performs the Lagrangian portion. The two codes are run concurrently with the appropriate portions of a problem solved on their respective computational domains. Zapotec handles the coupling between the two domains. The application of the CEL methodology within Zapotec for modeling coupled blast/structure interaction will be investigated by a series of benchmark calculations. These benchmarks rely on data from the Conventional Weapons Effects Backfill (CONWEB) test series. In these tests, a 15.4-lb pipe-encased C-4 charge was detonated in soil at a 5-foot standoff from a buried test structure. The test structure was composed of a
NASA Astrophysics Data System (ADS)
Patricola, C. M.; Chang, P.; Saravanan, R.; Montuoro, R.
2012-04-01
The sensitivity of simulated strength, track, and structure of Hurricane Katrina to atmospheric model resolution, cumulus parameterization, and initialization time, as well as mesoscale ocean-atmosphere interactions with and without small-scale ocean-wave effect, are investigated with a fully coupled regional climate model. The atmosphere, ocean, and wave components are represented by the Weather Research and Forecasting Model (WRF), Regional Ocean Modeling System (ROMS), and Simulating WAves Nearshore (SWAN) model. Uncoupled atmosphere-only simulations with horizontal resolutions of 1, 3, 9, and 27 km show that while the simulated cyclone track is highly sensitive to initialization time, its dependence on model resolution is relatively weak. Using NCEP/CFSR reanalysis as initial and boundary conditions, WRF, even at low resolution, is able to track Katrina accurately for 3 days before it made landfall on August 29, 2005. Katrina's strength, however, is much more difficult to reproduce and exhibits a strong dependence on model resolution. At its lowest resolution (27 km), WRF is only capable of simulating a maximum strength of Category 2 storm. Even at 1 km resolution, the simulated Katrina only reaches Category 4 storm intensity. Further WRF experiments with and without cumulus parameterization reveal minor changes in strength. None of the WRF-only simulations capture the observed rapid intensification of Katrina to Category 5 when it passed over a warm Loop-Current eddy (LCE) in the Gulf of Mexico, suggesting that mesoscale ocean-atmosphere interactions involving LCEs may play a crucial role in Katrina's rapid intensification. Coupled atmosphere-ocean simulations are designed and carried out to investigate hurricane Katrina-LCE interactions with and without considering small-scale ocean wave processes in order to fully understand the dynamical ocean-atmosphere processes in the observed rapid cyclone intensification.
Interactions and thermoelectric effects in a parallel-coupled double quantum dot
NASA Astrophysics Data System (ADS)
Sierra, Miguel A.; Saiz-Bretín, M.; Domínguez-Adame, F.; Sánchez, David
2016-06-01
We investigate the nonequilibrium transport properties of a double quantum-dot system connected in parallel to two leads, including intradot electron-electron interaction. In the absence of interactions, the system supports a bound state in the continuum. This state is revealed as a Fano antiresonance in the transmission when the energy levels of the dots are detuned. Using the Keldysh nonequilibrium Green's-function formalism, we find that the occurrence of the Fano antiresonance survives in the presence of Coulomb repulsion. We give precise predictions for the experimental detection of bound states in the continuum. First, we calculate the differential conductance as a function of the applied voltage and the dot level detuning and find that crossing points in the diamond structure are revealed as minima due to the transmission antiresonances. Second, we determine the thermoelectric current in response to an applied temperature bias. In the linear regime, quantum interference gives rise to sharp peaks in the thermoelectric conductance. Remarkably, we find interaction-induced strong current nonlinearities for large thermal gradients that may lead to several nontrivial zeros in the thermocurrent. The latter property is especially attractive for thermoelectric applications.
NASA Astrophysics Data System (ADS)
Egeland, G. W.; Mariani, R. D.; Hartmann, T.; Porter, D. L.; Hayes, S. L.; Kennedy, J. R.
2013-01-01
Fast-reactor fuel alloys produce lanthanide fission products which migrate to the fuel/cladding interface causing fuel-cladding chemical interaction. To test viability of pinning these lanthanides, neodymium was selected as an iron interacting lanthanide and palladium was chosen as the dopant. An arc-melt produced 1:1 neodymium-palladium compound and pure neodymium were tested against iron in diffusion couples at temperatures above and below the Nd-Fe eutectic melting point.
NASA Astrophysics Data System (ADS)
Yeh, Wei-Hung
1999-10-01
The primary objective of this dissertation is to present a clear physical picture and useful insights of polarization effects in the diffraction of focused beams by grooved, multilayer-coated disks. The reading process of optical disk systems significantly relies on the reaction of the incident focused beam to the disk structure, may it be the groove profile or coating materials. The resulting complex-amplitude from diffraction is the main source for the readout signal. In the presence of the periodic pattern and the focused beam, however, different polarization states usually result in different complex-amplitudes. A good understanding of polarization effects in grooved multilayer disks is thus required for the optimum design of optical data storage systems. The pursuit of high-density recording inevitably drives the optical data storage industry to reduce the wavelength of light sources, decrease the track pitch of optical disks, and increase the numerical aperture of objective lenses. The track pitch and the size of the focused spot gradually approach the optical wavelength. Under these circumstances, the analysis of the interaction of focused beams with this type of high- frequency periodic disk using conventional scalar diffraction theory is no longer adequate. Only through vector diffraction study of polarization effects in the interaction of the focused beam with the periodic pattern can the characteristics of an optical disk system be fully understood and improved. Starting from the introduction of various polarization effects in optical disk systems and basic concepts of both scalar and vector diffraction theory, we then focus on the studies of diffraction patterns at the exit pupil of the objective lens and on the disk surface. Different behavior on the baseball pattern and in the effective groove depth is observed for the two polarization states. The use of the solid immersion lens to extensively increase the area density of optical disk systems prompts
NASA Technical Reports Server (NTRS)
Taylor, Peter R.; Lee, Timothy J.; Rendell, Alistair P.
1990-01-01
The recently proposed quadratic configuration interaction (QCI) method is compared with the more rigorous coupled cluster (CC) approach for a variety of chemical systems. Some of these systems are well represented by a single-determinant reference function and others are not. The finite order singles and doubles correlation energy, the perturbational triples correlation energy, and a recently devised diagnostic for estimating the importance of multireference effects are considered. The spectroscopic constants of CuH, the equilibrium structure of cis-(NO)2 and the binding energies of Be3, Be4, Mg3, and Mg4 were calculated using both approaches. The diagnostic for estimating multireference character clearly demonstrates that the QCI method becomes less satisfactory than the CC approach as non-dynamical correlation becomes more important, in agreement with a perturbational analysis of the two methods and the numerical estimates of the triple excitation energies they yield. The results for CuH show that the differences between the two methods become more apparent as the chemical systems under investigation becomes more multireference in nature and the QCI results consequently become less reliable. Nonetheless, when the system of interest is dominated by a single reference determinant both QCI and CC give very similar results.
Krishtopenko, S. S.
2015-02-15
The effect of the electron-electron interaction on the spin-resonance frequency in two-dimensional electron systems with Dresselhaus spin-orbit coupling is investigated. The oscillatory dependence of many-body corrections on the magnetic field is demonstrated. It is shown that the consideration of many-body interaction leads to a decrease or an increase in the spin-resonance frequency, depending on the sign of the g factor. It is found that the term cubic in quasimomentum in Dresselhaus spin-orbit coupling partially decreases exchange corrections to the spin resonance energy in a two-dimensional system.
Beam plasma interaction in strongly coupled plasmas
NASA Astrophysics Data System (ADS)
Rosenberg, Marlene; Kalman, Gabor J.; Kyrkos, Stamatios; Donko, Zoltan
2006-04-01
The well-known problem of beam-plasma instability acquires new aspects when one or both of the two components (the beam and the plasma) are strongly interacting. We have now theoretically considered the case when the plasma is in the solid phase and forms a lattice. In this situation, the inherent anisotropy of the lattice leads to a coupling between the longitudinal and transverse polarizations. One of the novel features of the beam-plasma instability in this scenario is the possible excitation of transverse modes, which should be an experimentally observable signature of the instability. We have initially concentrated on a 2D toy model with the beam lying in the lattice plane. At the same time, we have initiated a molecular dynamics simulation program for studying various aspects of the penetration of a beam into a plasma lattice. The beam parameters can be adjusted in order to see the effects of increasing coupling strength within the beam and to distinguish between collective phenomena and scattering on individual particles. When both components are strongly interacting, a number of remarkable phenomena—trapping of beam particles, creation of dislocations, local melting of the lattice—may be observed.
Vehicle systems: coupled and interactive dynamics analysis
NASA Astrophysics Data System (ADS)
Vantsevich, Vladimir V.
2014-11-01
This article formulates a new direction in vehicle dynamics, described as coupled and interactive vehicle system dynamics. Formalised procedures and analysis of case studies are presented. An analytical consideration, which explains the physics of coupled system dynamics and its consequences for dynamics of a vehicle, is given for several sets of systems including: (i) driveline and suspension of a 6×6 truck, (ii) a brake mechanism and a limited slip differential of a drive axle and (iii) a 4×4 vehicle steering system and driveline system. The article introduces a formal procedure to turn coupled system dynamics into interactive dynamics of systems. A new research direction in interactive dynamics of an active steering and a hybrid-electric power transmitting unit is presented and analysed to control power distribution between the drive axles of a 4×4 vehicle. A control strategy integrates energy efficiency and lateral dynamics by decoupling dynamics of the two systems thus forming their interactive dynamics.
Periat, Aurélie; Kohler, Isabelle; Thomas, Aurélien; Nicoli, Raul; Boccard, Julien; Veuthey, Jean-Luc; Schappler, Julie; Guillarme, Davy
2016-03-25
Reversed phase liquid chromatography (RPLC) coupled to mass spectrometry (MS) is the gold standard technique in bioanalysis. However, hydrophilic interaction chromatography (HILIC) could represent a viable alternative to RPLC for the analysis of polar and/or ionizable compounds, as it often provides higher MS sensitivity and alternative selectivity. Nevertheless, this technique can be also prone to matrix effects (ME). ME are one of the major issues in quantitative LC-MS bioanalysis. To ensure acceptable method performance (i.e., trueness and precision), a careful evaluation and minimization of ME is required. In the present study, the incidence of ME in HILIC-MS/MS and RPLC-MS/MS was compared for plasma and urine samples using two representative sets of 38 pharmaceutical compounds and 40 doping agents, respectively. The optimal generic chromatographic conditions in terms of selectivity with respect to interfering compounds were established in both chromatographic modes by testing three different stationary phases in each mode with different mobile phase pH. A second step involved the assessment of ME in RPLC and HILIC under the best generic conditions, using the post-extraction addition method. Biological samples were prepared using two different sample pre-treatments, i.e., a non-selective sample clean-up procedure (protein precipitation and simple dilution for plasma and urine samples, respectively) and a selective sample preparation, i.e., solid phase extraction for both matrices. The non-selective pretreatments led to significantly less ME in RPLC vs. HILIC conditions regardless of the matrix. On the contrary, HILIC appeared as a valuable alternative to RPLC for plasma and urine samples treated by a selective sample preparation. Indeed, in the case of selective sample preparation, the compounds influenced by ME were different in HILIC and RPLC, and lower and similar ME occurrence was generally observed in RPLC vs. HILIC for urine and plasma samples
NASA Astrophysics Data System (ADS)
Shahmansouri, M.; Mamun, A. A.
2015-07-01
The effects of strong electrostatic interaction among highly charged dust on multi-dimensional instability of dust-acoustic (DA) solitary waves in a magnetized strongly coupled dusty plasma by small- k perturbation expansion method have been investigated. We found that a Zakharov-Kuznetsov equation governs the evolution of obliquely propagating small amplitude DA solitary waves in such a strongly coupled dusty plasma. The parametric regimes for which the obliquely propagating DA solitary waves become unstable are identified. The basic properties, viz., amplitude, width, instability criterion, and growth rate, of these obliquely propagating DA solitary structures are found to be significantly modified by the effects of different physical strongly coupled dusty plasma parameters. The implications of our results in some space/astrophysical plasmas and some future laboratory experiments are briefly discussed.
NASA Astrophysics Data System (ADS)
Yamada, Takemi; Yamakawa, Youichi; Ōno, Yoshiaki
2010-01-01
The electronic state around a single vacancy in silicon crystal is investigated by using the Green's function approach. The triply degenerate charge states are found to be widely extended and account for extremely large elastic softening at low temperature as observed in recent ultrasonic experiments. When we include the LS coupling λSi on each Si atom, the 6-fold spin-orbital degeneracy for the V+ state with the valence +1 and spin 1/2 splits into Γ doublet groundstates and Γ8 quartet excited states with a reduced excited energy of O(λSi/10). We also consider the effect of couplings between electrons and Jahn-Teller phonons in the dangling bonds within the second order perturbation and find that the groundstate becomes Γ8 quartet which is responsible for the magnetic-field suppression of the softening in B-doped silicon.
NASA Astrophysics Data System (ADS)
Mvogo, Alain; Ben-Bolie, G. H.; Kofané, T. C.
2015-06-01
The dynamics of three coupled α-polypeptide chains of a collagen molecule is investigated with the influence of power-law long-range exciton-exciton interactions. The continuum limit of the discrete equations reveal that the collagen dynamics is governed by a set of three coupled nonlinear Schrödinger equations, whose dispersive coefficient depends on the LRI parameter r. We construct the analytic symmetric and asymmetric (antisymmetric) soliton solutions, which match with the structural features of collagen related with the acupuncture channels. These solutions are used as initial conditions for the numerical simulations of the discrete equations, which reveal a coherent transport of energy in the molecule for r > 3. The results also indicate that the width of the solitons is a decreasing function of r, which help to stabilize the solitons propagating in the molecule. To confirm further the efficiency of energy transport in the molecule, the modulational instability of the system is performed and the numerical simulations show that the energy can flow from one polypeptide chain to another in the form of nonlinear waves.
Coupling interaction of electromagnetic wave in a groove doublet configuration.
Ding, Lan; Liu, Jinsong; Wang, Dong; Wang, Kejia
2010-09-27
Based on the waveguide mode (WGM) method, coupling interaction of electromagnetic wave in a groove doublet configuration is studied. The formulation obtained by WGM method for a single groove [Prog. Electromagn. Res. 18, 1-17 (1998)] is extended to two grooves. By exploring the total scattered field of the configuration, coupling interaction ratios are defined to describe the interaction between grooves quantitatively. Since each groove in this groove doublet configuration is regarded as the basic unit, the effects of coupling interaction on the scattered fields of each groove can be investigated respectively. Numerical results show that an oscillatory behavior of coupling interaction is damped with increasing groove spacing. The incident and scattering angle dependence of coupling interaction is symmetrical when the two grooves are the same. For the case of two subwavelength grooves, the coupling interaction is not sensitive to the incident angle and scattering angle. Although the case of two grooves is discussed for simplicity, the formulation developed in this article can be generalized to arbitrary number of grooves. Moreover, our study offers a simple alternative to investigate and design metallic gratings, compact directional antennas, couplers, and other devices especially in low frequency regime such as THz and microwave domain. PMID:20941004
NASA Astrophysics Data System (ADS)
Pradhan, N.; Downer, C. W.; Liljedahl, A. K.; Marchenko, S. S.; Douglas, T. A.; Wahl, M.
2012-12-01
Climate warming is expected to degrade permafrost in many areas of Alaska which will dramatically affect surface hydrological, soil and vegetation regimes. Projections of long-term effects of climate warming on high latitude ecosystems require a representation of soil thermal state and hydrological dynamics. We developed a coupled framework to explicitly model the soil moisture effects of soil thermal conductivity and heat capacity and its effects on hydrological dynamics. Our model is the result of coupling the Gridded Surface Subsurface Hydrologic Analysis (GSSHA) model with the Geophysical Institute Permafrost Laboratory (GIPL) model. The model platform can account for the effect of frozen ground on hydrology by infiltration, lateral flows and storage capacity. The GIPL model simulates soil temperature dynamics and the depth of seasonal freezing and thawing by numerically solving a 1-D nonlinear heat equation with phase change. The GSSHA model is a spatially explicit hydrological model that simulates 2-D overland flow, 2-D groundwater flow, and 1-D flow in stream networks. We combined these two models into one framework and tested it using data from Caribou Poker Creek Research Watershed in Interior Alaska. Simulation results reproduce the typical characteristics observed in the watersheds underlain by permafrost, where the reduced storage capacity produces higher peak and lower base flow.
Interaction function of coupled bursting neurons
NASA Astrophysics Data System (ADS)
Xia, Shi; Jiadong, Zhang
2016-06-01
The interaction functions of electrically coupled Hindmarsh-Rose (HR) neurons for different firing patterns are investigated in this paper. By applying the phase reduction technique, the phase response curve (PRC) of the spiking neuron and burst phase response curve (BPRC) of the bursting neuron are derived. Then the interaction function of two coupled neurons can be calculated numerically according to the PRC (or BPRC) and the voltage time course of the neurons. Results show that the BPRC is more and more complicated with the increase of the spike number within a burst, and the curve of the interaction function oscillates more and more frequently with it. However, two certain things are unchanged: ϕ = 0, which corresponds to the in-phase synchronization state, is always the stable equilibrium, while the anti-phase synchronization state with ϕ = 0.5 is an unstable equilibrium. Project supported by the National Natural Science Foundation of China (Grant Nos. 11272065 and 11472061).
Interaction function of coupled bursting neurons
NASA Astrophysics Data System (ADS)
Xia, Shi; Jiadong, Zhang
2016-06-01
The interaction functions of electrically coupled Hindmarsh–Rose (HR) neurons for different firing patterns are investigated in this paper. By applying the phase reduction technique, the phase response curve (PRC) of the spiking neuron and burst phase response curve (BPRC) of the bursting neuron are derived. Then the interaction function of two coupled neurons can be calculated numerically according to the PRC (or BPRC) and the voltage time course of the neurons. Results show that the BPRC is more and more complicated with the increase of the spike number within a burst, and the curve of the interaction function oscillates more and more frequently with it. However, two certain things are unchanged: ϕ = 0, which corresponds to the in-phase synchronization state, is always the stable equilibrium, while the anti-phase synchronization state with ϕ = 0.5 is an unstable equilibrium. Project supported by the National Natural Science Foundation of China (Grant Nos. 11272065 and 11472061).
Effects of Spin-Orbit Coupling on the Spin-Rotation Interaction in the AsH2 Radical
NASA Astrophysics Data System (ADS)
Duxbury, Geoffrey; Alijah, Alexander
2014-06-01
The occurence of predissociation in the electronic spectrum of AsH2 is very dependent upon the magnitude of the spin-orbit coupling parameter of the central atom. Making use of Table 5.6 in "The Spectra and Dynamics of Diatomic Molecules, ELSEVIER" by H. Lefebvre-Brion and R.W. Field, it is possible to appreciate the rapid rate of increase of the spin-orbit constants associated with the heavy central atom in the di-hydrides NH2, PH2 and AsH2. The spin-orbit constants range from 42.7 cm-1 for NH2, to 191.3 cm-1 for PH2, and 1178 cm-1 for AsH2. The effects of spin-orbit coupling may be seen in a plot of the separation of the central RQ0,9 and PQ1,N sub-bands as the value of v2' increases from 0 to 5. As the value of v2' increases beyond 2 the spectrum becomes more and more fuzzy as the effects of predissociation become more obvious. This means that unlike the example of the behaviour of PH2, where the vibronic level pattern can be followed below and above the barrier to linearity, in AsH2 and AsD2 the absorption spectrum becomes completely diffuse below the barrier to linearity in the A 2A1 state. The change in the magnitude of the doublet splittings as v2' increases may be seen in the plots of the doublet splittings showing the spin-uncoupling as a result of the increase of overall rotation. In the absorption spectrum of SbH2, recorded in 1967 by T. Barrow in the Chemistry Department at Sheffield University, all the absorption features showed the effects of predissociation, consistent with a spin-orbit constant of 2834 cm-1 for the central atom of SbH2.
NASA Astrophysics Data System (ADS)
Archer-Nicholls, Scott; Lowe, Douglas; Schultz, David M.; McFiggans, Gordon
2016-05-01
The Weather Research and Forecasting model with Chemistry (WRF-Chem) has been used to simulate a region of Brazil heavily influenced by biomass burning. Nested simulations were run at 5 and 1 km horizontal grid spacing for three case studies in September 2012. Simulations were run with and without fire emissions, convective parameterisation on the 5 km domain, and aerosol-radiation interactions in order to explore the differences attributable to the parameterisations and to better understand the aerosol direct effects and cloud responses. Direct aerosol-radiation interactions due to biomass burning aerosol resulted in a net cooling, with an average short-wave direct effect of -4.08 ± 1.53 Wm-2. However, around 21.7 Wm-2 is absorbed by aerosol in the atmospheric column, warming the atmosphere at the aerosol layer height, stabilising the column, inhibiting convection, and reducing cloud cover and precipitation. The changes to clouds due to radiatively absorbing aerosol (traditionally known as the semi-direct effects) increase the net short-wave radiation reaching the surface by reducing cloud cover, producing a secondary warming that counters the direct cooling. However, the magnitude of the semi-direct effect was found to be extremely sensitive to the model resolution and the use of convective parameterisation. Precipitation became organised in isolated convective cells when not using a convective parameterisation on the 5 km domain, reducing both total cloud cover and total precipitation. The SW semi-direct effect varied from 6.06 ± 1.46 with convective parameterisation to 3.61 ± 0.86 Wm-2 without. Convective cells within the 1 km domain are typically smaller but with greater updraft velocity than equivalent cells in the 5 km domain, reducing the proportion of the domain covered by cloud in all scenarios and producing a smaller semi-direct effect. Biomass burning (BB) aerosol particles acted as cloud condensation nuclei (CCN), increasing the droplet number
Casimir Interaction from Magnetically Coupled Eddy Currents
Intravaia, Francesco; Henkel, Carsten
2009-09-25
We study the quantum and thermal fluctuations of eddy (Foucault) currents in thick metallic plates. A Casimir interaction between two plates arises from the coupling via quasistatic magnetic fields. As a function of distance, the relevant eddy current modes cross over from a quantum to a thermal regime. These modes alone reproduce previously discussed thermal anomalies of the electromagnetic Casimir interaction between good conductors. In particular, they provide a physical picture for the Casimir entropy whose nonzero value at zero temperature arises from a correlated, glassy state.
NASA Astrophysics Data System (ADS)
Li, F.; Newman, P. A.; Pawson, S.; Waugh, D. W.
2014-12-01
Stratospheric ozone depletion has played a dominant role in driving Antarctic climate change in the last decades. In order to capture the stratospheric ozone forcing, many coupled atmosphere-ocean general circulation models (AOGCMs) prescribe the Antarctic ozone hole using monthly and zonally averaged ozone field. However, the prescribed ozone hole has a high ozone bias and lacks zonal asymmetry. The impacts of these biases on model simulations, particularly on Southern Ocean and the Antarctic sea ice, are not well understood. The purpose of this study is to determine the effects of using interactive stratospheric chemistry instead of prescribed ozone on Antarctic and Southern Ocean climate change in an AOGCM. We compare two sets of ensemble simulations for the 1960-2010 period using different versions of the Goddard Earth Observing System 5 - AOGCM: one with interactive stratospheric chemistry, and the other with prescribed monthly and zonally averaged ozone and 6 other stratospheric radiative species calculated from the interactive chemistry simulations. Consistent with previous studies using prescribed sea surface temperatures and sea ice concentrations, the interactive chemistry runs simulate a deeper Antarctic ozone hole and consistently larger changes in surface pressure and surface winds than the prescribed ozone runs. The use of a coupled atmosphere-ocean model in this study enables us to determine the impact of these surface trend differences on Southern Ocean circulation and Antarctic sea ice. The larger surface wind trends in the interactive chemistry case lead to larger Southern Ocean circulation trends with stronger changes in northerly and westerly surface flow near the Antarctica continent and stronger upwelling near 60ºS. Using interactive chemistry also simulates a larger decrease of sea ice concentrations. Our results highlight the importance of using interactive chemistry in order to correctly capture the influences of stratospheric ozone
ANTENNA-COUPLED LIGHT-MATTER INTERACTIONS
NOVOTNY, LUKAS
2014-01-10
This project is focused on antenna-coupled photon emission from single quantum emitters. The properties of optical antennas are tailored to control different photophysical parameters, such as the excited state lifetime, the saturation intensity, and the quantum yield [3]. Using a single molecule coupled to an optical antenna whose position and properties can be controllably adjusted we established a detailed and quantitative understanding of light-matter interactions in nanoscale environments. We have studied various quantum emitters: single molecules [11], quantum dots [7], rareearth ions [2], and NV centers in diamond [19]. We have systematically studied the interaction of these emitters with optical antennas. The overall objective was to establish a high-level of control over the light-matter interaction. In order to eliminate the coupling to the environment, we have taken a step further and explored the possibility of levitating the quantum emitter in high vacuum. What started as a side-project soon became a main activity in our research program and led us to the demonstration of vacuum trapping and cooling of a nanoscale particle [14].
Interplay of Coulomb interaction and spin-orbit coupling
NASA Astrophysics Data System (ADS)
Bünemann, Jörg; Linneweber, Thorben; Löw, Ute; Anders, Frithjof B.; Gebhard, Florian
2016-07-01
We employ the Gutzwiller variational approach to investigate the interplay of Coulomb interaction and spin-orbit coupling in a three-orbital Hubbard model. Already in the paramagnetic phase we find a substantial renormalization of the spin-orbit coupling that enters the effective single-particle Hamiltonian for the quasiparticles. Only close to half band-filling and for sizable Coulomb interaction do we observe clear signatures of Hund's atomic rules for spin, orbital, and total angular momentum. For a finite local Hund's rule exchange interaction we find a ferromagnetically ordered state. The spin-orbit coupling considerably reduces the size of the ordered moment, it generates a small ordered orbital moment, and it induces a magnetic anisotropy. To investigate the magnetic anisotropy energy, we use an external magnetic field that tilts the magnetic moment away from the easy axis (1 ,1 ,1 ) .
Nonlinear interaction of meta-atoms through optical coupling
Slobozhanyuk, A. P.; Kapitanova, P. V.; Filonov, D. S.; Belov, P. A.; Powell, D. A.; Shadrivov, I. V.; Kivshar, Yu. S.; Lapine, M.; McPhedran, R. C.
2014-01-06
We propose and experimentally demonstrate a multi-frequency nonlinear coupling mechanism between split-ring resonators. We engineer the coupling between two microwave resonators through optical interaction, whilst suppressing the direct electromagnetic coupling. This allows for a power-dependent interaction between the otherwise independent resonators, opening interesting opportunities to address applications in signal processing, filtering, directional coupling, and electromagnetic compatibility.
Interaction Patterns of Premarital Couples: Typological Assessment Over Time.
ERIC Educational Resources Information Center
Norem, Rosalie H.; Olson, David H.
1983-01-01
Studied interaction styles of premarital couples (N=148) and developed a typology of couple interaction at two points in time before marriage. Results showed only 7 percent of the couples had the same type of interaction at the two testings, supporting the hypothesis that premarital relationships are fluid. (WAS)
Shahmansouri, M.; Mamun, A. A.
2014-03-15
Linear and nonlinear propagation of dust-acoustic waves in a magnetized strongly coupled dusty plasma is theoretically investigated. The normal mode analysis (reductive perturbation method) is employed to investigate the role of ambient/external magnetic field, obliqueness, and effective electrostatic dust-temperature in modifying the properties of linear (nonlinear) dust-acoustic waves propagating in such a strongly coupled dusty plasma. The effective electrostatic dust-temperature, which arises from strong electrostatic interactions among highly charged dust, is considered as a dynamical variable. The linear dispersion relation (describing the linear propagation characteristics) for the obliquely propagating dust-acoustic waves is derived and analyzed. On the other hand, the Korteweg-de Vries equation describing the nonlinear propagation of the dust-acoustic waves (particularly, propagation of dust-acoustic solitary waves) is derived and solved. It is shown that the combined effects of obliqueness, magnitude of the ambient/external magnetic field, and effective electrostatic dust-temperature significantly modify the basic properties of linear and nonlinear dust-acoustic waves. The results of this work are compared with those observed by some laboratory experiments.
NASA Astrophysics Data System (ADS)
Fridman, Yu. A.; Kozhemyako, O. V.; Eingorn, B. L.
2001-05-01
The spectra of the coupled magnetoelastic waves of an easy-plane ferromagnet with a negative biquadratic interaction are investigated. It is shown that in this case the existence region of the quadrupolar phase is narrowed substantially in comparison with the case of a positive biquadratic interaction. The phase diagram of the system is constructed.
Mode coupling and cavity-quantum-dot interactions in a fiber-coupled microdisk cavity
Srinivasan, Kartik; Painter, Oskar
2007-02-15
A quantum master equation model for the interaction between a two-level system and whispering-gallery modes (WGMs) of a microdisk cavity is presented, with specific attention paid to current experiments involving a semiconductor quantum dot (QD) embedded in a fiber-coupled Al{sub x}Ga{sub 1-x}As microdisk cavity. In standard single mode cavity QED, three important rates characterize the system: the QD-cavity coupling rate g, the cavity decay rate {kappa}, and the QD dephasing rate {gamma}{sub (perpendicular)}. A more accurate model of the microdisk cavity includes two additional features. The first is a second cavity mode that can couple to the QD, which for an ideal microdisk corresponds to a traveling wave WGM propagating counter to the first WGM. The second feature is a coupling between these two traveling wave WGMs, at a rate {beta}, due to backscattering caused by surface roughness that is present in fabricated devices. We consider the transmitted and reflected signals from the cavity for different parameter regimes of {l_brace}g,{beta},{kappa},{gamma}{sub (perpendicular)}{r_brace}. A result of this analysis is that even in the presence of negligible roughness-induced backscattering, a strongly coupled QD mediates coupling between the traveling wave WGMs, resulting in an enhanced effective coherent coupling rate g={radical}(2)g{sub 0} corresponding to that of a standing wave WGM with an electric field maximum at the position of the QD. In addition, analysis of the second-order correlation function of the reflected signal from the cavity indicates that regions of strong photon antibunching or bunching may be present depending upon the strength of coupling of the QD to each of the cavity modes. Such intensity correlation information will likely be valuable in interpreting experimental measurements of a strongly coupled QD to a bimodal WGM cavity.
Lebedev, V. S. Narits, A. A.
2013-10-15
Ion-pair formation processes are studied in collisions of Rydberg atoms with neutral particles possessing small electron affinities. Nonadiabatic transitions from a Rydberg covalent term to an ionic term of a quasi-molecule are considered using the modified Landau-Zener theory supplemented with calculation of survival factors of an anion decaying in the Coulomb field of a positive ion core. Using the technique of irreducible tensor operators and the momentum representation of the wavefunction of a highly excited atom, exact expressions are obtained for transition matrix elements and the ionic-covalent coupling parameter. The approach developed in the paper provides the description beyond the scope of a conventional assumption about a small variation of the wavefunction of the Rydberg atom on the range of electron coordinates determined by the characteristic radius of the wavefunction of the anion. This allows one to correctly consider long-range effects of the interaction between a weakly bound electron and the neutral core of a negative ion in processes under study. It is shown by the example of thermal collisions of Xe(nf) atoms with CH{sub 3}CN molecules that this is very important for a reliable quantitative description of anion formation with a low binding energy. The results are compared with experiments and calculations performed within the framework of a number of approximate methods.
Schuback, Nina; Schallenberg, Christina; Duckham, Carolyn; Maldonado, Maria T.; Tortell, Philippe D.
2015-01-01
Iron availability directly affects photosynthesis and limits phytoplankton growth over vast oceanic regions. For this reason, the availability of iron is a crucial variable to consider in the development of active chlorophyll a fluorescence based estimates of phytoplankton primary productivity. These bio-optical approaches require a conversion factor to derive ecologically-relevant rates of CO2-assimilation from estimates of electron transport in photosystem II. The required conversion factor varies significantly across phytoplankton taxa and environmental conditions, but little information is available on its response to iron limitation. In this study, we examine the role of iron limitation, and the interacting effects of iron and light availability, on the coupling of photosynthetic electron transport and CO2-assimilation in marine phytoplankton. Our results show that excess irradiance causes increased decoupling of carbon fixation and electron transport, particularly under iron limiting conditions. We observed that reaction center II specific rates of electron transport (ETRRCII, mol e- mol RCII-1 s-1) increased under iron limitation, and we propose a simple conceptual model for this observation. We also observed a strong correlation between the derived conversion factor and the expression of non-photochemical quenching. Utilizing a dataset from in situ phytoplankton assemblages across a coastal – oceanic transect in the Northeast subarctic Pacific, this relationship was used to predict ETRRCII: CO2-assimilation conversion factors and carbon-based primary productivity from FRRF data, without the need for any additional measurements. PMID:26171963
NASA Astrophysics Data System (ADS)
Zhang, Yu-Qing; Zhu, Zhong-Hua; Peng, Zhao-Hui; Jiang, Chun-Lei; Tan, Lei
2016-07-01
We theoretically investigate the single-photon transport in a hybrid atom-optomechanical system embedded with two dipole-coupled two-level atoms, interacting with a single-mode optical waveguide. The transmission amplitudes for the single-photon propagation in such a hybrid system are obtained via a real-space approach. It is shown that the dipole-dipole interaction can significantly change the amplitudes and symmetries of the single-photon spectra. Interestingly, we find that the dipole-dipole interaction plays a similar role as does the positive atom-cavity detuning. In addition, the influence from the atomic dissipation can be weakened by increasing the dipole-dipole interaction.
Interaction of solitons with a string of coupled quantum dots
NASA Astrophysics Data System (ADS)
Kumar, Vijendra; Swami, O. P.; Taneja, S.; Nagar, A. K.
2016-05-01
In this paper, we develop a theory for discrete solitons interaction with a string of coupled quantum dots in view of the local field effects. Discrete nonlinear Schrodinger (DNLS) equations are used to describe the dynamics of the string. Numerical calculations are carried out and results are analyzed with the help of matlab software. With the help of numerical solutions we demonstrate that in the quantum dots string, Rabi oscillations (RO) are self trapped into stable bright Rabi solitons. The Rabi oscillations in different types of nanostructures have potential applications to the elements of quantum logic and quantum memory.
NASA Astrophysics Data System (ADS)
Hong, K. K.; Ryu, J. B.; Park, C. Y.; Huh, J. Y.
2008-01-01
The solid-state, cross-interaction between the Ni layer on the component side and the Cu pad on the printed circuit board (PCB) side in ball grid array (BGA) solder joints was investigated by employing Ni(15 μm)/Sn(65 μm)/Cu ternary diffusion couples. The ternary diffusion couples were prepared by sequentially electroplating Sn and Ni on a Cu foil and were aged isothermally at 150, 180, and 200°C. The growth of the intermetallic compound (IMC) layer on the Ni side was coupled with that on the Cu side by the mass flux across the Sn layer that was caused by the difference in the Ni content between the (Cu1- x Ni x )6Sn5 layer on the Ni side and the (Cu1- y Ni y )6Sn5 layer on the Cu side. As the consequence of the coupling, the growth rate of the (Cu1- x Ni x )6 Sn5 layer on the Ni side was rapidly accelerated by decreasing Sn layer thickness and increasing aging temperature. Owing to the cross-interaction with the top Ni layer, the growth rate of the (Cu1- y Ni y )6Sn5 layer on the Cu side was accelerated at 150°C and 180°C but was retarded at 200°C, while the growth rate of the Cu3Sn layer was always retarded. The growth kinetic model proposed in an attempt to interpret the experimental results was able to reproduce qualitatively all of the important experimental observations pertaining to the growth of the IMC layers in the Ni/Sn/Cu diffusion couple.
Different coupling modes mediate cortical cross-frequency interactions.
Helfrich, Randolph F; Herrmann, Christoph S; Engel, Andreas K; Schneider, Till R
2016-10-15
Cross-frequency coupling (CFC) has been suggested to constitute a highly flexible mechanism for cortical information gating and processing, giving rise to conscious perception and various higher cognitive functions in humans. In particular, it might provide an elegant tool for information integration across several spatiotemporal scales within nested or coupled neuronal networks. However, it is currently unknown whether low-frequency (theta/alpha) or high-frequency gamma oscillations orchestrate cross-frequency interactions, raising the question of who is master and who is slave. While correlative evidence suggested that at least two distinct CFC modes exist, namely, phase-amplitude-coupling (PAC) and amplitude-envelope correlations (AEC), it is currently unknown whether they subserve distinct cortical functions. Novel non-invasive brain stimulation tools, such as transcranial alternating current stimulation (tACS), now provide the unique opportunity to selectively entrain the low- or high-frequency component and study subsequent effects on CFC. Here, we demonstrate the differential modulation of CFC during selective entrainment of alpha or gamma oscillations. Our results reveal that entrainment of the low-frequency component increased PAC, where gamma power became preferentially locked to the trough of the alpha oscillation, while gamma-band entrainment enhanced AECs and reduced alpha power. These results provide causal evidence for the functional role of coupled alpha and gamma oscillations for visual processing. PMID:26608244
Different coupling modes mediate cortical cross-frequency interactions.
Helfrich, Randolph F; Herrmann, Christoph S; Engel, Andreas K; Schneider, Till R
2016-10-15
Cross-frequency coupling (CFC) has been suggested to constitute a highly flexible mechanism for cortical information gating and processing, giving rise to conscious perception and various higher cognitive functions in humans. In particular, it might provide an elegant tool for information integration across several spatiotemporal scales within nested or coupled neuronal networks. However, it is currently unknown whether low-frequency (theta/alpha) or high-frequency gamma oscillations orchestrate cross-frequency interactions, raising the question of who is master and who is slave. While correlative evidence suggested that at least two distinct CFC modes exist, namely, phase-amplitude-coupling (PAC) and amplitude-envelope correlations (AEC), it is currently unknown whether they subserve distinct cortical functions. Novel non-invasive brain stimulation tools, such as transcranial alternating current stimulation (tACS), now provide the unique opportunity to selectively entrain the low- or high-frequency component and study subsequent effects on CFC. Here, we demonstrate the differential modulation of CFC during selective entrainment of alpha or gamma oscillations. Our results reveal that entrainment of the low-frequency component increased PAC, where gamma power became preferentially locked to the trough of the alpha oscillation, while gamma-band entrainment enhanced AECs and reduced alpha power. These results provide causal evidence for the functional role of coupled alpha and gamma oscillations for visual processing.
Computational and experimental techniques for coupled acoustic/structure interactions.
Sumali, Anton Hartono; Pierson, Kendall Hugh; Walsh, Timothy Francis; Dohner, Jeffrey Lynn; Reese, Garth M.; Day, David Minot
2004-01-01
This report documents the results obtained during a one-year Laboratory Directed Research and Development (LDRD) initiative aimed at investigating coupled structural acoustic interactions by means of algorithm development and experiment. Finite element acoustic formulations have been developed based on fluid velocity potential and fluid displacement. Domain decomposition and diagonal scaling preconditioners were investigated for parallel implementation. A formulation that includes fluid viscosity and that can simulate both pressure and shear waves in fluid was developed. An acoustic wave tube was built, tested, and shown to be an effective means of testing acoustic loading on simple test structures. The tube is capable of creating a semi-infinite acoustic field due to nonreflecting acoustic termination at one end. In addition, a micro-torsional disk was created and tested for the purposes of investigating acoustic shear wave damping in microstructures, and the slip boundary conditions that occur along the wet interface when the Knudsen number becomes sufficiently large.
Du, Mao-Hua
2015-04-02
We know that native point defects play an important role in carrier transport properties of CH3NH3PbI3. However, the nature of many important defects remains controversial due partly to the conflicting results reported by recent density functional theory (DFT) calculations. In this Letter, we show that self-interaction error and the neglect of spin–orbit coupling (SOC) in many previous DFT calculations resulted in incorrect positions of valence and conduction band edges, although their difference, which is the band gap, is in good agreement with the experimental value. Moreover, this problem has led to incorrect predictions of defect-level positions. Hybrid density functional calculations,more » which partially correct the self-interaction error and include the SOC, show that, among native point defects (including vacancies, interstitials, and antisites), only the iodine vacancy and its complexes induce deep electron and hole trapping levels inside of the band gap, acting as nonradiative recombination centers.« less
Coupled mode theory for photonic crystal cavity-waveguide interaction.
Waks, Edo; Vuckovic, Jelena
2005-06-27
We derive a coupled mode theory for the interaction of an optical cavity with a waveguide that includes waveguide dispersion. The theory can be applied to photonic crystal cavity waveguide structures. We derive an analytical solution to the add and drop spectra arising from such interactions in the limit of linear dispersion. In this limit, the spectra can accurately predict the cold cavity quality factor (Q) when the interaction is weak. We numerically solve the coupled mode equations for the case of a cavity interacting with the band edge of a periodic waveguide, where linear dispersion is no longer a good approximation. In this regime, the density of states can distort the add and drop spectra. This distortion can lead to more than an order of magnitude overestimation of the cavity Q.
Resonance tuning due to Coulomb interaction in strong near-field coupled metamaterials
Roy Chowdhury, Dibakar; Xu, Ningning; Zhang, Weili; Singh, Ranjan
2015-07-14
Coulomb's law is one of the most fundamental laws of physics that describes the electrostatic interaction between two like or unlike point charges. Here, we experimentally observe a strong effect of Coulomb interaction in tightly coupled terahertz metamaterials where the split-ring resonator dimers in a unit cell are coupled through their near fields across the capacitive split gaps. Using a simple analytical model, we evaluated the Coulomb parameter that switched its sign from negative to positive values indicating the transition in the nature of Coulomb force from being repulsive to attractive depending upon the near field coupling between the split ring resonators. Apart from showing interesting effects in the strong coupling regime between meta-atoms, Coulomb interaction also allows an additional degree of freedom to achieve frequency tunable dynamic metamaterials.
Chaos in generically coupled phase oscillator networks with nonpairwise interactions
NASA Astrophysics Data System (ADS)
Bick, Christian; Ashwin, Peter; Rodrigues, Ana
2016-09-01
The Kuramoto-Sakaguchi system of coupled phase oscillators, where interaction between oscillators is determined by a single harmonic of phase differences of pairs of oscillators, has very simple emergent dynamics in the case of identical oscillators that are globally coupled: there is a variational structure that means the only attractors are full synchrony (in-phase) or splay phase (rotating wave/full asynchrony) oscillations and the bifurcation between these states is highly degenerate. Here we show that nonpairwise coupling—including three and four-way interactions of the oscillator phases—that appears generically at the next order in normal-form based calculations can give rise to complex emergent dynamics in symmetric phase oscillator networks. In particular, we show that chaos can appear in the smallest possible dimension of four coupled phase oscillators for a range of parameter values.
What causes size coupling in fruit--frugivore interaction webs?
Burns, K C
2013-02-01
The simplest and arguably the most ubiquitous pattern in seed dispersal mutualisms is size coupling: large frugivores tend to consume larger fruits and small frugivores tend to consume smaller fruits. Despite the simplicity of this pattern, the potential mechanisms responsible for fruit--frugivore size coupling are mechanistically divergent and poorly resolved. Size coupling could arise deterministically, if large frugivores actively seek out larger fruits to maximize their foraging efficiency. Alternatively, size coupling could also arise passively, if frugivores forage randomly, but are able to consume only those fruit species that are smaller than their gape width. I observed birds forage for fruits in a New Zealand forest reserve at approximately five-day intervals for six years to test for fruit--frugivore size coupling. I then derived a suite of network analyses to establish whether fruit--frugivore size coupling was best explained by active or passive foraging by frugivores. Results showed a strikingly strong pattern in size coupling; the average size of fruits consumed by each frugivore species increased with their maximum gape width. Simulation analyses revealed that over 70% of variation in interaction frequencies in the observed fruit-frugivore web could be explained by a size-constrained, passive, foraging model. Foraging models in which birds foraged actively for different-sized fruits to improve their foraging efficiency performed more poorly. Results were therefore consistent with the hypothesis that apparently nonrandom patterns in seed dispersal mutualisms can sometimes arise from simple stochastic processes.
Interaction of acoustic waves generated by coupled plate
NASA Technical Reports Server (NTRS)
Cuschieri, J. M.
1990-01-01
When two substructures are coupled, the acoustic field generated by the motion of each of the substructures will interact with the motion of the other substructure. This would be the case of a structure enclosing an acoustic cavity. A technique to model the interaction of the generated sound fields from the two components of a coupled structure, and the influence of this interaction on the vibration of the structural components is presented. Using a mobility power flow approach, each element of the substructure is treated independently both when developing the structural response and when determining the acoustic field generated by this component. The presence of the other substructural components is introduced by assuming these components to be rigid baffles. The excitation of one of the substructures is assumed to be by an incident acoustic wave which is dependent of the motion of the substructure. The sound field generated by the motion of the substructure is included in the solution of the response.
An interacting dark energy model with nonminimal derivative coupling
NASA Astrophysics Data System (ADS)
Nozari, Kourosh; Behrouz, Noushin
2016-09-01
We study cosmological dynamics of an extended gravitational theory that gravity is coupled non-minimally with derivatives of a dark energy component and there is also a phenomenological interaction between the dark energy and dark matter. Depending on the direction of energy flow between the dark sectors, the phenomenological interaction gets two different signs. We show that this feature affects the existence of attractor solution, the rate of growth of perturbations and stability of the solutions. By considering an exponential potential as a self-interaction potential of the scalar field, we obtain accelerated scaling solutions that are attractors and have the potential to alleviate the coincidence problem. While in the absence of the nonminimal derivative coupling there is no attractor solution for phantom field when energy transfers from dark matter to dark energy, we show an attractor solution exists if one considers an explicit nonminimal derivative coupling for phantom field in this case of energy transfer. We treat the cosmological perturbations in this setup with details to show that with phenomenological interaction, perturbations can grow faster than the minimal case.
Cavity -Quantum Dot interactions and mode coupling in a nanocavity
NASA Astrophysics Data System (ADS)
Kasisomayajula, Vijay; Russo, Onofrio
2009-03-01
We describe an approach for realizing effective manipulation of single electron state level transitions for quantum dots mediated by a nano-cavity. The two quantum dots interact with the cavity for the two dot system in the coulomb blockade energy region. Because of the zero dimensional structure of the quantum dots, the system can be implemented to be a characteristic entity for an efficient generator of single photons. This process is emphatically more selective in the coulomb/spin blockade region, where also, the system efficiency of the single photon event is most likely more probable. Whereas, it is clear that the photon efficiency is small, the cavity quantum electrodynamics (CQED) nature suggests an enhancement in the electron energy state being occupied by the second quantum dot. This is more likely with very strong coupling of the quantum dots to the cavity with cavity quality factors larger than perhaps 10^5. Quality factors in excess of 10^5 have been demonstrated experimentally^1. 1. K. Srinivasan, M. Borselli, T. J. Johnson, P. E. Barclay, O. Painter, A. Stintz, and S. Krishna, Appl. Phys. Lett. 86, 151106 (2005). [ISI
Proxemics in Couple Interactions: Rekindling an Old Optic.
Sluzki, Carlos E
2016-03-01
Utilizing as a lens the interpersonal implications of physical interpersonal distances in social contexts (a set of variables present during the professional discourse during the 1960s and 1970s, to then fade away), this article explores interactive process displayed by the protagonic couple in Bela Bartok's opera "Bluebeard Castle," an exercise aimed at underlining the value of maintaining proxemics as an explicit level of observation for clinical practice and interpersonal research.
Proxemics in Couple Interactions: Rekindling an Old Optic.
Sluzki, Carlos E
2016-03-01
Utilizing as a lens the interpersonal implications of physical interpersonal distances in social contexts (a set of variables present during the professional discourse during the 1960s and 1970s, to then fade away), this article explores interactive process displayed by the protagonic couple in Bela Bartok's opera "Bluebeard Castle," an exercise aimed at underlining the value of maintaining proxemics as an explicit level of observation for clinical practice and interpersonal research. PMID:26558850
Analysis of Coupled Reaction-Diffusion Equations for RNA Interactions
Hohn, Maryann E.; Li, Bo; Yang, Weihua
2015-01-01
We consider a system of coupled reaction-diffusion equations that models the interaction between multiple types of chemical species, particularly the interaction between one messenger RNA and different types of non-coding microRNAs in biological cells. We construct various modeling systems with different levels of complexity for the reaction, nonlinear diffusion, and coupled reaction and diffusion of the RNA interactions, respectively, with the most complex one being the full coupled reaction-diffusion equations. The simplest system consists of ordinary differential equations (ODE) modeling the chemical reaction. We present a derivation of this system using the chemical master equation and the mean-field approximation, and prove the existence, uniqueness, and linear stability of equilibrium solution of the ODE system. Next, we consider a single, nonlinear diffusion equation for one species that results from the slow diffusion of the others. Using variational techniques, we prove the existence and uniqueness of solution to a boundary-value problem of this nonlinear diffusion equation. Finally, we consider the full system of reaction-diffusion equations, both steady-state and time-dependent. We use the monotone method to construct iteratively upper and lower solutions and show that their respective limits are solutions to the reaction-diffusion system. For the time-dependent system of reaction-diffusion equations, we obtain the existence and uniqueness of global solutions. We also obtain some asymptotic properties of such solutions. PMID:25601722
Strongly coupled large N spectrum of two matrices coupled via a Yang-Mills interaction
Cook, Martin N. H.; Rodrigues, Joao P.
2008-09-15
We consider the large N spectrum of the quantum mechanical Hamiltonian of two Hermitian matrices coupled via a Yang-Mills interaction. In a framework where one of the matrices is treated exactly and the other is treated as a creation operator impurity, the difference equation associated with the Yang-Mills interaction is derived and solved exactly for two impurities. In this case, the full string tension corrected spectrum depends on two momenta. For a specific value of one of these momenta, the spectrum has the same structure as that of giant magnon bound states. States with general number of impurities are also discussed.
McKay, Garrett; Couch, Kylie D; Mezyk, Stephen P; Rosario-Ortiz, Fernando L
2016-08-01
We studied the formation of photochemically produced reactive intermediates (RI) from dissolved organic matter (DOM). Specifically, we focused on the effects of variable molecular weight and chemical reduction on the optical properties of DOM (absorbance and fluorescence) and the formation of singlet oxygen ((1)O2), DOM triplet excited states ((3)DOM*), and the hydroxyl radical ((•)OH). The data are largely evaluated in terms of a charge-transfer (CT) model, but deficiencies in the model to explain the data are pointed out when evident. A total of two sets of samples were studied that were subjected to different treatments; the first set included secondary-treated wastewaters and a wastewater-impacted stream, and the second was a DOM isolate. Treatments included size fractionation and chemical reduction using sodium borohydride. Taken as a whole, the results demonstrate that decreasing molecular weight and borohydride reduction work in opposition regarding quantum efficiencies for (1)O2 and (3)DOM* production but in concert for fluorescence and (•)OH production. The optical and photochemical data provide evidence for a limited role of CT interactions occurring in lower-molecular-weight DOM molecules. In addition, the data suggest that the observed optical and photochemical properties of DOM are a result of multiple populations of chromophores and that their relative contribution is changed by molecular-weight fractionation and borohydride reduction.
Tools for investigating functional interactions between ligands and G-protein-coupled receptors.
Lerner, M R
1994-04-01
A general assay for evaluating functional interactions between ligands and G-protein-coupled receptors within minutes has been developed. The system uses the principles employed by animals such as reptiles, amphibians and fish to control their colors. In nature, activation of G-protein-coupled receptors expressed by skin cells called chromatophores effects pigment redistribution within the cells to change an animal's coloration. The in vitro 'chameleon in a dish' equivalent can use essentially any cloned G-protein-coupled receptor. PMID:7517590
The validity of retrospectively reported conflict interactions in couples.
Backer-Fulghum, Lindsey M; Sanford, Keith
2015-04-01
This study investigated the extent to which researchers and clinicians can obtain valid retrospective self-reports of couples' conflict interactions outside a laboratory setting. A distinction was made between relationship attribute variance, regarding a shared perspective of both partners, and informant-specific variance, regarding the unique vantage point of each partner. By examining convergent and divergent associations for each type of variance, this study clarified the risk that responses might be influenced by informant-specific biases related to levels of relationship satisfaction. This study also investigated potential moderators of validity. Participants included both members of 269 married and cohabiting couples (538 individuals) who completed online questionnaires. Results were analyzed using a correlated trait-correlated method minus one model. The total true variance included large components of both shared relationship attribute variance and informant-specific variance. Although the shared component was moderately correlated with relationship satisfaction, the informant-specific component was mostly distinct from satisfaction, suggesting minimal bias. Convergent correlations between partners were strong and mostly unrelated to potential moderating variables, albeit slightly smaller than reported in studies conducted in laboratory settings. The results generally support the validity for retrospective self-reports of conflict interactions, especially when reports are obtained from both members of a couple.
The validity of retrospectively reported conflict interactions in couples.
Backer-Fulghum, Lindsey M; Sanford, Keith
2015-04-01
This study investigated the extent to which researchers and clinicians can obtain valid retrospective self-reports of couples' conflict interactions outside a laboratory setting. A distinction was made between relationship attribute variance, regarding a shared perspective of both partners, and informant-specific variance, regarding the unique vantage point of each partner. By examining convergent and divergent associations for each type of variance, this study clarified the risk that responses might be influenced by informant-specific biases related to levels of relationship satisfaction. This study also investigated potential moderators of validity. Participants included both members of 269 married and cohabiting couples (538 individuals) who completed online questionnaires. Results were analyzed using a correlated trait-correlated method minus one model. The total true variance included large components of both shared relationship attribute variance and informant-specific variance. Although the shared component was moderately correlated with relationship satisfaction, the informant-specific component was mostly distinct from satisfaction, suggesting minimal bias. Convergent correlations between partners were strong and mostly unrelated to potential moderating variables, albeit slightly smaller than reported in studies conducted in laboratory settings. The results generally support the validity for retrospective self-reports of conflict interactions, especially when reports are obtained from both members of a couple. PMID:25689089
Dzyaloshinskii-Moriya Interaction and Spiral Order in Spin-orbit Coupled Optical Lattices
Gong, Ming; Qian, Yinyin; Yan, Mi; Scarola, V. W.; Zhang, Chuanwei
2015-01-01
We show that the recent experimental realization of spin-orbit coupling in ultracold atomic gases can be used to study different types of spin spiral order and resulting multiferroic effects. Spin-orbit coupling in optical lattices can give rise to the Dzyaloshinskii-Moriya (DM) spin interaction which is essential for spin spiral order. By taking into account spin-orbit coupling and an external Zeeman field, we derive an effective spin model in the Mott insulator regime at half filling and demonstrate that the DM interaction in optical lattices can be made extremely strong with realistic experimental parameters. The rich finite temperature phase diagrams of the effective spin models for fermions and bosons are obtained via classical Monte Carlo simulations. PMID:26014458
Coupled nucleotide covariations reveal dynamic RNA interaction patterns.
Gultyaev, A P; Franch, T; Gerdes, K
2000-01-01
Evolutionarily conserved structures in related RNA molecules contain coordinated variations (covariations) of paired nucleotides. Analysis of covariations is a very powerful approach to deduce phylogenetically conserved (i.e., functional) conformations, including tertiary interactions. Here we discuss conserved RNA folding pathways that are revealed by covariation patterns. In such pathways, structural requirements for alternative pairings cause some nucleotides to covary with two different partners. Such "coupled" covariations between three or more nucleotides were found in various types of RNAs. The analysis of coupled covariations can unravel important features of RNA folding dynamics and improve phylogeny reconstruction in some cases. Importantly, it is necessary to distinguish between multiple covariations determined by mutually exclusive structures and those determined by tertiary contacts. PMID:11105748
Snapin interacts with G-protein coupled receptor PKR2.
Song, Jian; Li, Jie; Liu, Hua-die; Liu, Wei; Feng, Yong; Zhou, Xiao-Tao; Li, Jia-Da
2016-01-15
Mutations in Prokineticin receptor 2 (PKR2), a G-protein-coupled receptor, have been identified in patients with Kallmann syndrome and/or idiopathic hypogonadotropic hypogonadism, characterized by delayed puberty and infertility. In this study, we performed yeast two-hybrid screening by using PKR2 C-terminus (amino acids 333-384) as a bait, and identified Snapin as a novel interaction partner for PKR2. The interaction of Snapin and PKR2 was confirmed in GST pull-down and co-immunoprecipitation studies. We further demonstrated that two α-helix domains in Snapin are required for the interaction. And the interactive motifs of PKR2 were mapped to YFK (343-345) and HWR (351-353), which shared a similar sequence of two aromatic amino acids followed by a basic amino acid. Disruption of Snapin-PKR2 interaction did not affect PKR2 signaling, but increased the ligand-induced degradation, implying a role of Snapin in the trafficking of PKR2.
Magnetic interactions in exchange-coupled yet unbiased IrMn/NiCu bilayers
NASA Astrophysics Data System (ADS)
Cichelero, R.; Harres, A.; Sossmeier, K. D.; Schmidt, J. E.; Geshev, J.
2013-10-01
This paper reports experimental and model magnetization results obtained on exchange-coupled ferromagnet/antiferromagnet (FM/AF) bilayers that show zero net bias. The coercivity of the films, either irradiated with He or implanted with Ge ions at 40 keV, varies significantly with the fluence used. We employed the remanence plots technique in order to estimate the nature of the interactions present and check if there exists a correlation between their type and the coercivity variations. The analysis of the remanence plots through numerical simulations based on the Landau-Lifshitz-Gilbert equation demonstrated that outcomes of interactions within the FM layer could be distinguished from those coming from coupling at the FM/AF interface and that demagnetizing interaction effects could be achieved without the presence of dipolar interactions. Our findings indicate that such experiments could give selective information on modifications caused by a post-deposition treatment in each layer of the film.
Shear viscosity from effective couplings of gravitons
Cai Ronggen; Nie Zhangyu; Sun Yawen
2008-12-15
We calculate the shear viscosity of field theories with gravity duals using Kubo formula by calculating the Green function of dual transverse gravitons and confirm that the value of the shear viscosity is fully determined by the effective coupling of transverse gravitons on the horizon. We calculate the effective coupling of transverse gravitons for Einstein and Gauss-Bonnet gravities coupled with matter fields, respectively. Then we apply the resulting formula to the case of AdS Gauss-Bonnet gravity with F{sup 4} term corrections of Maxwell field and discuss the effect of F{sup 4} terms on the ratio of the shear viscosity to entropy density.
Limits on Higgs boson couplings in Effective field theory
NASA Astrophysics Data System (ADS)
Belyaev, N.; Reid, T.
2016-02-01
We review the Effective Field Theory (EFT) to make projections on physics beyond the Standard Model in the Higgs sector. We provide relations between the non-Standard Model couplings of the Strongly-Interacting Light Higgs (SILH) effective Lagrangian implemented in the eHDecay package and the corresponding terms of the spin-0 Higgs Characterisation model's effective Lagrangian used with the aMC@NLO Monte Carlo generator. Constraints on BSM couplings are determined on the basis of existing experimental limits on Higgs boson width and branching ratios.
Modeling the interaction between two dimensional strongly coupled confined dust clusters
Djebli, M.; Issaad, M.; Rouaiguia, L.
2010-03-15
Numerical simulations based on the Monte Carlo method are conducted to investigate ground-state configurations and phase transitions of strongly coupled dust particles. The interaction between negatively charged dust particles is modeled by three different potentials, namely, Coulomb, Yukawa, and logarithmic. The effect of random charge fluctuation is taken into account for a dominant charging process by particles collection and in the presence of two dimensional parabolic confinement potential. Structural arrangement and phase transition are found to be dependent on the potential interaction and the charge fluctuation. The changes in the melting temperature, when the charge fluctuation is taken into account, are particularly noticeable for systems with particles interacting through logarithmic potential.
Spin-orbit coupled Bose-Einstein condensates with Rydberg-dressing interaction
NASA Astrophysics Data System (ADS)
Lü, Hao; Zhu, Shao-Bing; Qian, Jun; Wang, Yu-Zhu
2015-09-01
Interaction between Rydberg atoms can be used to control the properties of interatomic interaction in ultracold gases by weakly dressing the atoms with a Rydberg state. Here we investigate the effect of the Rydberg-dressing interaction on the ground-state properties of a Bose-Einstein condensate imposed by Raman-induced spin-orbit coupling. We find that, in the case of SU(2)-invariant s-wave interactions, the gas is only in the plane-wave phase and the zero-momentum phase is absent. In particular, we also predict an unexpected magnetic stripe phase composed of two plane-wave components with unequal weight when s-wave interactions are non-symmetric, which originates from the Rydberg-dressing interaction. Project supported by the National Basic Research Program of China (Grant No. 2011CB921504) and the National Natural Science Foundation of China (Grant No. 11104292).
NASA Astrophysics Data System (ADS)
Bukač, M.
2016-05-01
We model the interaction between an incompressible, viscous fluid, thin elastic structure and a poroelastic material. The poroelastic material is modeled using the Biot's equations of dynamic poroelasticity. The fluid, elastic structure and the poroelastic material are fully coupled, giving rise to a nonlinear, moving boundary problem with novel energy estimates. We present a modular, loosely coupled scheme where the original problem is split into the fluid sub-problem, elastic structure sub-problem and poroelasticity sub-problem. An energy estimate associated with the stability of the scheme is derived in the case where one of the coupling parameters, β, is equal to zero. We present numerical tests where we investigate the effects of the material properties of the poroelastic medium on the fluid flow. Our findings indicate that the flow patterns highly depend on the storativity of the poroelastic material and cannot be captured by considering fluid-structure interaction only.
Coupling interactions between sulfurous acid and the hydroperoxyl radical.
Li, Ping; Ma, Zhi-Ying; Wang, Wei-Hua; Shen, Zhi-Tao; Bi, Si-Wei; Sun, Hai-Tao; Bu, Yu-Xiang
2010-02-22
Radical-molecule complexes associated with the hydroperoxyl radical (HOO) play an important role in atmospheric chemistry. Herein, the nature of the coupling interactions between sulfurous acid (H(2)SO(3)) and the HOO radical is systematically investigated at the B3LYP/6-311++G(3df,3pd) level of theory in combination with the atoms in molecules (AIM) theory, the natural bond orbital (NBO) method, and energy decomposition analyses (EDA). Eight stable stationary points possessing double H-bonding features were located on the H(2)SO(3)...HOO potential energy surface. The largest binding energies of -12.27 and -11.72 kcal mol(-1) are observed for the two most stable complexes, where both of them possess strong double intermolecular H-bonds of partially covalence. Moreover, the characteristics of the IR spectra for the two most stable complexes are discussed to provide some help for their possible experimental identification. PMID:20041456
Controlled Crystallinity and Fundamental Coupling Interactions in Nanocrystals
NASA Astrophysics Data System (ADS)
Ouyang, Min
2009-03-01
Metal and semiconductor nanocrystals show many unusual properties and functionalities, and can serve as model system to explore fundamental quantum and classical coupling interactions as well as building blocks of many practical applications. However, because of their small size, these nanoparticles typically exhibit different crystalline properties as compared with their bulk counterpart, and controlling crystallinity (and structural defects) within nanoparticles has posed significant technical challenges. In this talk, I will firstly apply silver metal nanoparticles as an example and present a novel chemical synthetic technique to achieve unprecedented crystallinity control at the nanoscale. This engineering of nanocrystallinity enables manipulation of intrinsic chemical functionalities, physical properties as well as nano-device performance [1]. For example, I will highlight that electron- phonon coupling constant can be significantly reduced by about four times and elastic modulus is increased ˜40% in perfect single crystalline silver nanoparticles as compared with those in disordered twinned nanoparticles. One important application of metal nanoparticles is nanoscale sensors. I will thus demonstrate that performance of nanoparticles based molecular sensing devices can be optimized with three times improvement of figure-of-merit if perfect single crystalline nanoparticles are applied. Lastly, I will present our related studies on semiconductor nanocrystals as well as their hybrid heterostructures. These discussions should offer important implications for our understanding of the fundamental properties at nanoscale and potential applications of metal nanoparticles. [4pt] [1] Yun Tang and Min Ouyang, Nature Materials, 6, 754, 2007.
Weighty dynamics: exploring couples' perceptions of post-weight-loss interaction.
Romo, Lynsey Kluever; Dailey, René M
2014-01-01
Although romantic couples can use communication to help one another lose weight and maintain weight loss, the effect of weight loss on partner interaction is less understood. However, an examination of the interpersonal context in which partners manage their weight is important to help partners negotiate their weight, their relationship, and the U.S. obesity epidemic. Guided by systems theory, this study explored partners' perceptions of post-weight-loss interaction in relationships in which one partner lost weight and the other did not. Through qualitative questionnaires of 42 adults (21 romantic couples), the dyadic investigation revealed that while losing weight resulted in positive interaction for many partners (e.g., engaging in a shared healthy lifestyle), shedding weight also yielded some negative consequences (e.g., non-weight-loss partner criticism). The extent to which partners embraced new weight management rules and patterns largely influenced post-weight-loss communication and behavior. PMID:24156394
Effective multi-Higgs couplings to gluons
NASA Astrophysics Data System (ADS)
Spira, Michael
2016-10-01
Standard-Model Higgs bosons are dominantly produced via the gluon-fusion mechanism gg → H at the LHC, i.e. in a loop-mediated process with top loops providing the dominant contribution. For the measured Higgs boson mass of ˜ 125 GeV the limit of heavy top quarks provides a reliable approximation as long as the relative QCD corrections are scaled with the full mass-dependent LO cross section. In this limit the Higgs coupling to gluons can be described by an effective Lagrangian. The same approach can also be applied to the coupling of more than one Higgs boson to gluons. We will derive the effective Lagrangian for multi-Higgs couplings to gluons up to N4LO thus extending previous results for more than one Higgs boson. Moreover we discuss gluonic Higgs couplings up to NNLO, if several heavy quarks contribute.
Cotunneling Drag Effect in Coulomb-Coupled Quantum Dots.
Keller, A J; Lim, J S; Sánchez, David; López, Rosa; Amasha, S; Katine, J A; Shtrikman, Hadas; Goldhaber-Gordon, D
2016-08-01
In Coulomb drag, a current flowing in one conductor can induce a voltage across an adjacent conductor via the Coulomb interaction. The mechanisms yielding drag effects are not always understood, even though drag effects are sufficiently general to be seen in many low-dimensional systems. In this Letter, we observe Coulomb drag in a Coulomb-coupled double quantum dot and, through both experimental and theoretical arguments, identify cotunneling as essential to obtaining a correct qualitative understanding of the drag behavior.
Cotunneling Drag Effect in Coulomb-Coupled Quantum Dots
NASA Astrophysics Data System (ADS)
Keller, A. J.; Lim, J. S.; Sánchez, David; López, Rosa; Amasha, S.; Katine, J. A.; Shtrikman, Hadas; Goldhaber-Gordon, D.
2016-08-01
In Coulomb drag, a current flowing in one conductor can induce a voltage across an adjacent conductor via the Coulomb interaction. The mechanisms yielding drag effects are not always understood, even though drag effects are sufficiently general to be seen in many low-dimensional systems. In this Letter, we observe Coulomb drag in a Coulomb-coupled double quantum dot and, through both experimental and theoretical arguments, identify cotunneling as essential to obtaining a correct qualitative understanding of the drag behavior.
Laser coupling effects on structural material under different surface conditions
NASA Astrophysics Data System (ADS)
Feng, Guobing; Wei, Chenghua; Wu, Lixiong; Chen, Linzhu; Lin, Xinwei; Zhang, Jianmin; Ma, Zhiliang
2013-05-01
The laser coupling effect of material is a fundamental factor to influence laser interaction with matter. The coupling coefficient, which is the material absorptance of the input laser energy, depends on the surface conditions of materials, such as temperature, incident angle, surface airflow, oxidizing environment, and so on. To measure the laser coupling characteristics of materials, two typical online measuring apparatuses were developed in our laboratory. One is based on a conjugated hemi-ellipsoidal reflectometer, which is suitable to measure the laser coupling coefficients of different temperature in vacuum and air environments. The other is based on an integrating sphere and a simple airflow simulator, which can be applied to online measure the laser absorptance of materials subjected to surface airflow. The laser coupling effects on two types of structural materials, which are alloy steels and composite materials, are given in this paper. With the conjugated ellipsoidal reflectometer, the laser coupling effects on a typical alloy steel are investigated in different temperatures under the vacuum and air environment, and the experimental results are analyzed. According the results, metal oxidization plays a key role in the laser coupling enhancement effects. Especially, when the metal is subjected to high power laser irradiation in the high subsonic airflow, metal oxidization which is an exothermic reaction enhances the laser damage effect and the convective heat loss is negligible. Finally, the laser coupling effects on a typical composite material subjected to airflow are studied by using the integrating sphere with an airflow simulator, and the experimental results of laser absorptance during the laser ablation are presented.
Tensor coupling effect on relativistic symmetries
NASA Astrophysics Data System (ADS)
Chen, ShouWan; Li, DongPeng; Guo, JianYou
2016-08-01
The similarity renormalization group is used to transform the Dirac Hamiltonian with tensor coupling into a diagonal form. The upper (lower) diagonal element becomes a Schr¨odinger-like operator with the tensor component separated from the original Hamiltonian. Based on the operator, the tensor effect of the relativistic symmetries is explored with a focus on the single-particle energy contributed by the tensor coupling. The results show that the tensor coupling destroying (improving) the spin (pseudospin) symmetry is mainly attributed to the coupling of the spin-orbit and the tensor term, which plays an opposite role in the single-particle energy for the (pseudo-) spin-aligned and spin-unaligned states and has an important influence on the shell structure and its evolution.
Relativistic K-LL Auger spectra in the intermediate-coupling scheme with configuration interaction
NASA Technical Reports Server (NTRS)
Chen, M. H.; Crasemann, B.; Mark, H.
1980-01-01
Theoretical K-LL Auger spectra from relativistic Dirac-Hartree-Slater calculations in intermediate coupling with configuration interaction (ICWCI) are considered. Calculated transition rates for 25 elements with Z between 18 and 96, inclusive, are listed and compare well with experimental data. Relativistic effects are found to be important above Z equal to about 35, and ICWCI is necessary to describe the spectra for Z less than about 60.
Coupled ice sheet-climate interactions during the Last Interglacial simulated with LOVECLIM
NASA Astrophysics Data System (ADS)
Goelzer, H.; Huybrechts, P.; Loutre, M.; Fichefet, T.
2013-12-01
The Last Interglacial warm period (LIG, ~130 to 115 kyr BP) represents a real-world test case for the stability of the Greenland and Antarctic ice sheets, both thought to have lost considerable amounts of ice compared to their present-day configuration. We use the Earth system model of intermediate complexity LOVECLIM version 1.3 to perform transient simulations over the LIG forced with changes in orbital parameters and greenhouse gases. The model includes thermomechanically coupled models of the Greenland and Antarctic ice sheets, which are interactively coupled with the atmosphere and ocean components. We present modeling results with focus on the evolution of the polar ice sheets and their sea-level contribution, ice-climate interactions and inter-hemispheric coupling. LOVECLIM simulates annual mean temperature and summer temperature anomalies over central Greenland relative to the present day that peak at 5.5 °C and 10.7 °C, respectively. The Greenland ice sheet sea-level contribution peaks at between 1.0 and 2.6 m mainly caused by increased summer temperatures. While changes in surface melting have a negligible effect for the evolution of the Antarctic ice sheet during the LIG, a peak sea-level contribution of 2.1 m is governed by West Antarctic grounding-line retreat. For both ice sheets interactive ice-climate coupling is crucial to produce a temperature evolution over the ice sheets better in line with ice core records.
NASA Astrophysics Data System (ADS)
Rajput, Gagan; Kumar, Rajendra; Ajay
2014-09-01
Using non-equilibrium Green's function approach, we study electronic transport through a parallel double quantum dot (DQD) system symmetrically coupled to conventional superconducting leads. Andreev bound states (ABS) and corresponding resonant Cooper pair electron transmission through such a DQD-superconductor tunnel junction around the Fermi energy, a manifestation of Josephson effect, occur due to proximity effect as a result of superconducting order parameter. Interdot tunnel coupling in parallel coupled DQD system and Coulomb interactions regulate the Josephson effect in a very significant manner. Further, it is also found that interdot tunnel coupling has reverse effect on ABS and Cooper pair tunneling in the presence and absence of Coulomb interactions.
Coupled modeling of cement/claystone interactions and radionuclide migration
NASA Astrophysics Data System (ADS)
De Windt, L.; Pellegrini, D.; van der Lee, J.
2004-02-01
The interactions between cement and a clayey host-rock of an underground repository for intermediate-level radioactive waste are studied with the reactive transport code HYTEC for supporting performance assessment. Care is taken in using relevant time scales (100,000 years) and dimensions. Based on a literature review, three hypotheses are considered with respect to the mineralogical composition of the claystone and the neo-formed phases. In the long term, the pH is buffered for all hypotheses and important mineral transformations occur both in cement and the host-rock. The destruction of the primary minerals is localized close to the cement/claystone interface and is characterized by the precipitation of secondary phases with retention properties (illite, zeolite). However, beyond the zone of intense mineral transformations, the pore water chemistry is also disturbed over a dozen meters due to an attenuated but continuous flux of hydroxyl, potassium and calcium ions. Four interdependent mechanisms control the profile in the whole system: diffusion of the alkaline plume, mineralogical buffering, ion exchange and clogging of the pore space at the cement/claystone interface. The migration of a selected group of radionuclides (Cs, Ra, Tc and U) is explicitly integrated in the simulations of the strongly coupled system. Theoretical profiles of distribution coefficient (Kd) and solubility limit values are derived from the simulations, and their sensitivity with respect to the system evolution is estimated.
Rodrigues, Joao P.; Zaidi, Alia
2010-10-15
We derive a planar sector of the large N nonsupersymmetric background of the quantum mechanical Hamiltonian of two Hermitian matrices coupled via a Yang-Mills interaction, in terms of the density of eigenvalues of one of the matrices. This background satisfies an implicit nonlinear integral equation, with a perturbative small coupling expansion and a solvable large coupling solution, which is obtained. The energy of system and the expectation value of several correlators are obtained in this strong coupling limit. They are free of infrared divergences.
Chen Zhixin; Zhou Zhengwei; Zhou Xingxiang; Zhou Xiangga; Guo Guangcan
2010-02-15
We propose a scheme to simulate one-dimensional XXZ-type Heisenberg spin models with competing interactions between nearest neighbors (NNs) and next NNs in photon-coupled microcavities. Our scheme exploits the rich resources and flexible controls available in such a system to realize arbitrarily adjustable ratios between the effective NN and next-NN coupling strengths. Such a powerful capability allows us to simulate frustration phenomena and disorder behaviors in one-dimensional systems arising from next-NN interactions, a large class of problems of great importance in condensed-matter physics. Our scheme is robust due to the lack of atomic excitations, which suppresses spontaneous emission and cavity decay strongly.
Spatial resolution effect of light coupling structures
Li, Juntao; Li, Kezheng; Schuster, Christian; Su, Rongbin; Wang, Xuehua; Borges, Ben-Hur V.; Krauss, Thomas F.; Martins, Emiliano R.
2015-01-01
The coupling of light between free space and thin film semiconductors is an essential requirement of modern optoelectronic technology. For monochromatic and single mode devices, high performance grating couplers have been developed that are well understood. For broadband and multimode devices, however, more complex structures, here referred to as “coupling surfaces”, are required, which are often difficult to realise technologically. We identify general design rules based on the Fourier properties of the coupling surface and show how they can be used to determine the spatial resolution required for the coupler’s fabrication. To our knowledge, this question has not been previously addressed, but it is important for the understanding of diffractive nanostructures and their technological realisation. We exemplify our insights with solar cells and UV photodetectors, where high-performance nanostructures that can be realised cost-effectively are essential. PMID:26678574
Smith, Timothy W; Berg, Cynthia A; Florsheim, Paul; Uchino, Bert N; Pearce, Gale; Hawkins, Melissa; Henry, Nancy J M; Beveridge, Ryan M; Skinner, Michelle A; Olsen-Cerny, Chrisanna
2009-06-01
Prior theory and research regarding age differences in marital interaction suggest that older couples display and experience more positivity and less negativity than middle-aged couples. However, studies of overt behavior in older couples are relatively rare and have emphasized disagreement, neglecting other important contexts for older couples such as collaboration during everyday problem solving. Further, the affiliation or communion dimension of social interaction (i.e., warmth vs. hostility) is commonly assessed but not the control or agency dimension (e.g., dominance vs. submissiveness). The present study examined affect, cognitive appraisals, and overt behavior during disagreement (i.e., discussing a current conflict) and collaboration (i.e., planning errands) in 300 middle-aged and older married couples. Older couples reported less negative affect during disagreement and rated spouses as warmer than did middle-aged couples. However, these effects were eliminated when older couples' greater marital satisfaction was controlled. For observed behavior, older couples displayed little evidence of greater positivity and reduced negativity-especially women. During collaboration, older couples displayed a unique blend of warmth and control, suggesting a greater focus on emotional and social concerns during problem solving. PMID:19485646
Interacting spin-orbit-coupled spin-1 Bose-Einstein condensates
NASA Astrophysics Data System (ADS)
Sun, Kuei; Qu, Chunlei; Xu, Yong; Zhang, Yongping; Zhang, Chuanwei
2016-02-01
The recent experimental realization of spin-orbit (SO) coupling for spin-1 ultracold atoms opens an interesting avenue for exploring SO-coupling-related physics in large-spin systems, which is generally unattainable in electronic materials. In this paper, we study the effects of interactions between atoms on the ground states and collective excitations of SO-coupled spin-1 Bose-Einstein condensates (BECs) in the presence of a spin-tensor potential. We find that ferromagnetic interaction between atoms can induce a stripe phase exhibiting in-phase or out-of-phase modulating patterns between spin-tensor and zero-spin-component density waves. We characterize the phase transitions between different phases using the spin-tensor density as well as the collective dipole motion of the BEC. We show that there exists a double maxon-roton structure in the Bogoliubov-excitation spectrum, attributed to the three band minima of the SO-coupled spin-1 BEC.
Liu, Jialu; Xu, Ji; Gu, Sumin; Nicholson, Bruce J; Jiang, Jean X
2011-01-15
Both connexin 50 (Cx50) and aquaporin 0 (AQP0) have important roles in lens development and homeostasis, and their mutations are associated with human congenital cataracts. We have previously shown that Cx50 directly interacts with AQP0. Here, we demonstrate the importance of the Cx50 intracellular loop (IL) domain in mediating the interaction with AQP0 in the lens in vivo. AQP0 significantly increased (~20-30%) the intercellular coupling and conductance of Cx50 gap junctions. However, this increase was not observed when the IL domain was replaced with those from other lens connexins. The Cx50-AQP0 interaction had no effect on Cx50 hemichannel function. A fusion protein containing three extracellular loop domains of AQP0 efficiently blocked the cell-to-cell adhesion of AQP0 and attenuated the stimulatory effect of AQP0 on Cx50 gap junction conductance. These data suggest that the specific interaction between Cx50 and AQP0 enhances the coupling of Cx50 gap junctions, but not hemichannels, through the cell adhesion function of AQP0. This result establishes a physiological role of AQP0 in the functional regulation of gap junction channels.
Decoherence dynamics of interacting qubits coupled to a bath of local optical phonons
NASA Astrophysics Data System (ADS)
Lone, Muzaffar Qadir; Yarlagadda, S.
2016-04-01
We study decoherence in an interacting qubit system described by infinite range Heisenberg model (IRHM) in a situation where the system is coupled to a bath of local optical phonons. Using perturbation theory in polaron frame of reference, we derive an effective Hamiltonian that is valid in the regime of strong spin-phonon coupling under nonadiabatic conditions. It is shown that the effective Hamiltonian commutes with the IRHM upto leading orders of perturbation and thus has the same eigenstates as the IRHM. Using a quantum master equation with Markovian approximation of dynamical evolution, we show that the off-diagonal elements of the density matrix do not decay in the energy eigen basis of IRHM.
Receptor-coupled effector systems and their interactions
Wiener, E.C.
1988-01-01
We investigated the modulation of intracellular signal generation by receptor-coupled effector systems in B lymphocytes, and whether these alterations are consistent with the effects of prostaglandins. TPA (12-O-tetradecanoyl phorbol-13-acetate) and sn-1,2,-dioctanoylglycerol (diC{sub 8}) substitute for lipid derived signals which activate protein kinase C. Pretreating splenocytes from athymic nude mice with 100nM TPA or 5 {mu}M diC{sub 8} potentiated the forskolin-induced increased in cAMP (measured by radioimmunoassay) 2.5 and 3.0 times (respectively), but they decreased the PGE{sub 1}-induced cAMP rise 48% and 35% (respectively). Goat anti-mouse IgM, which activates diacylglycerol production, potentiated the forskolin-induced cAMP increase by 76%, but reduced that of PGE{sub 1} by 30%. Rabbit anti-mouse IgG, its F(ab{prime}){sub 2} fragment, or goat anti-mouse IGM induced increases in the cytosolic free (Ca{sup 2+}), (Ca{sup 2+}){sub i}, which TPA inhibited. In contrast, TPA potential antibody-induced {sup 3}H-thymidine (85x) and {sup 3}H-uridine (30x) uptake in B lymphocytes.
NASA Astrophysics Data System (ADS)
Nap, Rikkert; Szleifer, Igal
2014-03-01
A key challenge in nanomedicine is to design carrier system for drug delivery that selectively binds to target cells without binding to healthy cells. A common strategy is to end-functionalize the polymers coating of the delivery device with specific ligands that bind strongly to overexpressed receptors. Such devices are usually unable to discriminate between receptors found on benign and malignant cells. We demonstrate, theoretically, how one can achieve selective binding to target cells by using multiple physical and chemical interactions. We study the effective interactions between a polymer decorated nanosized micelle or solid nanoparticle with model lipid layers. The polymer coating contains a mixture of two polymers, one neutral for protection and the other a polybase with a functional end-group to optimize specific binding and electrostatic interactions with the charged lipid head-groups found on the lipid surface. The strength of the binding for the combined system is much larger than the sum of the independent electrostatic or specific ligand-receptor binding. The search for optimal binding conditions lead to the finding of a non-additive coupling that exists in systems where chemical equilibrium, molecular organization, and physical interactions are coupled together.
Cotunneling Drag Effect in Coulomb-Coupled Quantum Dots.
Keller, A J; Lim, J S; Sánchez, David; López, Rosa; Amasha, S; Katine, J A; Shtrikman, Hadas; Goldhaber-Gordon, D
2016-08-01
In Coulomb drag, a current flowing in one conductor can induce a voltage across an adjacent conductor via the Coulomb interaction. The mechanisms yielding drag effects are not always understood, even though drag effects are sufficiently general to be seen in many low-dimensional systems. In this Letter, we observe Coulomb drag in a Coulomb-coupled double quantum dot and, through both experimental and theoretical arguments, identify cotunneling as essential to obtaining a correct qualitative understanding of the drag behavior. PMID:27541473
Earthquake nucleation in a stochastic fault model of globally coupled units with interaction delays
NASA Astrophysics Data System (ADS)
Vasović, Nebojša; Kostić, Srđan; Franović, Igor; Todorović, Kristina
2016-09-01
In present paper we analyze dynamics of fault motion by considering delayed interaction of 100 all-to-all coupled blocks with rate-dependent friction law in presence of random seismic noise. Such a model sufficiently well describes a real fault motion, whose prevailing stochastic nature is implied by surrogate data analysis of available GPS measurements of active fault movement. Interaction of blocks in an analyzed model is studied as a function of time delay, observed both for dynamics of individual faults and phenomenological models. Analyzed model is examined as a system of all-to-all coupled blocks according to typical assumption of compound faults as complex of globally coupled segments. We apply numerical methods to show that there are local bifurcations from equilibrium state to periodic oscillations, with an occurrence of irregular aperiodic behavior when initial conditions are set away from the equilibrium point. Such a behavior indicates a possible existence of a bi-stable dynamical regime, due to effect of the introduced seismic noise or the existence of global attractor. The latter assumption is additionally confirmed by analyzing the corresponding mean-field approximated model. In this bi-stable regime, distribution of event magnitudes follows Gutenberg-Richter power law with satisfying statistical accuracy, including the b-value within the real observed range.
Du, Mao-Hua
2015-04-02
We know that native point defects play an important role in carrier transport properties of CH3NH3PbI3. However, the nature of many important defects remains controversial due partly to the conflicting results reported by recent density functional theory (DFT) calculations. In this Letter, we show that self-interaction error and the neglect of spin–orbit coupling (SOC) in many previous DFT calculations resulted in incorrect positions of valence and conduction band edges, although their difference, which is the band gap, is in good agreement with the experimental value. Moreover, this problem has led to incorrect predictions of defect-level positions. Hybrid density functional calculations, which partially correct the self-interaction error and include the SOC, show that, among native point defects (including vacancies, interstitials, and antisites), only the iodine vacancy and its complexes induce deep electron and hole trapping levels inside of the band gap, acting as nonradiative recombination centers.
NASA Astrophysics Data System (ADS)
Colpitts, C. A.; Cattell, C. A.; Broughton, M.; Engebretson, M. J.
2015-12-01
We will show observations of waveform bursts using the Electric Field and Waves (EFW) burst data on the Van Allen Probes satellites with intermediate frequency waves such as whistler mode, magnetosonic and lower hybrid. These observations show very strong modulation of these waves by lower frequency waves such as EMIC or ULF. We are analyzing the burst data and cross coupling between wave modes to determine how prevalent the cross coupling between wave modes is and under what conditions it occurs. To supplement the EFW data, each satellite is also equipped with a full complement of particle instruments, including the HOPE instrument measuring lower energy (1 eV - 50 keV) particles and MagEIS instruments measuring higher energy (20 keV - 5 MeV) particles. The energy and angular resolution of these detectors are sufficient to resolve the scattering and energization arising from the distinct wave modes, using the signatures in the trapped electron populations predicted by theory for the various mechanisms. Comparison of the burst waveform data with the electron data from HOPE and MagEIS, for times with and without coupling between the wave modes, will allow us to identify how the cross coupling affects electron dynamics in the radiation belts. The significance of wave-particle interactions in the formation and depletion of the radiation belts has long been established, but is still not completely understood. Specifically, pitch angle scattering from waves such as plasmaspheric hiss and electromagnetic ion cyclotron [EMIC] waves near the duskside plasmapause is known to contribute to electron loss from the radiation belts, primarily through precipitation into the atmosphere. Higher frequency waves such as whistler mode chorus and magnetosonic waves observed near the equator in the lower hybrid frequency range are widely believed to be primary means for electron energization. However, these and other competing processes often occur simultaneously, and an accurate model
Longitudinal coupling effect in microfiber Bragg gratings
NASA Astrophysics Data System (ADS)
Zhao, Ping; Zhang, Jihua; Wang, Guanghui; Jiang, Meng; Ping Shum, Perry; Zhang, Xinliang
2012-10-01
We theoretically present longitudinal coupling effect (LCE) in air-cladding microfiber Bragg gratings (MFBGs). Distinct from conventional weakly-guiding optical fibers, large longitudinal electric field (Ez) exists in wavelength-scale microfibers. Due to LCE, MFBG reflectivity can be reduced by more than 30% within the band-gap and the full width at half maximum (FWHM) is obviously narrowed. This theoretical analytical work is instructive to precisely design and fabricate MFBGs that are promising in the areas of optical sensing and nanophotonics.
A critical phase induced by interplay of spin-orbit coupling and Coulomb interaction
NASA Astrophysics Data System (ADS)
Moon, Eun-Gook; Xu, Cenke; Kim, Yong Baek; Balents, Leon
2013-03-01
We study long range Coulomb interaction effect on the Luttinger Hamiltonian in three spatial dimensions, which describes strong spin orbit coupling intrinsically. The Hamiltonian has energy spectrum of inverted band gap semiconductors as in well-known HgTe; only one quadratic band touching point exists at the gamma point in Brillouin zone protected by the cubic and time reversal symmetries. Using controlled renormalization group techniques, we find that long-range Coulomb interaction converts the quadratic band touching state into a non-Fermi liquid (NFL) state, in some ways analogous to the Luttinger liquid state in one dimension. Consequently, all physical quantities become scale invariant and show deviations from non-interacting electrons' properties. Temperature and field dependence of various thermodynamic functions are obtained. Moreover, our ground state can be viewed as a parent state of topological insulators, magnetic metals, and Weyl semi-metals by breaking either cubic symmetry or time-reversal symmetry. The strong Coulomb interaction changes phase boundaries qualitatively and phase diagrams with the Coulomb interaction are provided. Applications to iridium-oxides materials are also discussed.
Evolution of a G protein-coupled receptor response by mutations in regulatory network interactions.
Di Roberto, Raphaël B; Chang, Belinda; Trusina, Ala; Peisajovich, Sergio G
2016-08-04
All cellular functions depend on the concerted action of multiple proteins organized in complex networks. To understand how selection acts on protein networks, we used the yeast mating receptor Ste2, a pheromone-activated G protein-coupled receptor, as a model system. In Saccharomyces cerevisiae, Ste2 is a hub in a network of interactions controlling both signal transduction and signal suppression. Through laboratory evolution, we obtained 21 mutant receptors sensitive to the pheromone of a related yeast species and investigated the molecular mechanisms behind this newfound sensitivity. While some mutants show enhanced binding affinity to the foreign pheromone, others only display weakened interactions with the network's negative regulators. Importantly, the latter changes have a limited impact on overall pathway regulation, despite their considerable effect on sensitivity. Our results demonstrate that a new receptor-ligand pair can evolve through network-altering mutations independently of receptor-ligand binding, and suggest a potential role for such mutations in disease.
2014-01-01
Background The various cell types and their relative numbers in multicellular organisms are controlled by growth factors and related extracellular molecules which affect genetic expression pathways. However, these substances may have both/either inhibitory and/or stimulatory effects on cell division and cell differentiation depending on the cellular environment. It is not known how cells respond to these substances in such an ambiguous way. Many cellular effects have been investigated and reported using cell culture from cancer cell lines in an effort to define normal cellular behaviour using these abnormal cells. A model is offered to explain the harmony of cellular life in multicellular organisms involving interacting extracellular substances. Methods A basic model was proposed based on asymmetric cell division and evidence to support the hypothetical model was accumulated from the literature. In particular, relevant evidence was selected for the Insulin-Like Growth Factor system from the published data, especially from certain cell lines, to support the model. The evidence has been selective in an attempt to provide a picture of normal cellular responses, derived from the cell lines. Results The formation of a pair of coupled cells by asymmetric cell division is an integral part of the model as is the interaction of couplet molecules derived from these cells. Each couplet cell will have a receptor to measure the amount of the couplet molecule produced by the other cell; each cell will be receptor-positive or receptor-negative for the respective receptors. The couplet molecules will form a binary complex whose level is also measured by the cell. The hypothesis is heavily supported by selective collection of circumstantial evidence and by some direct evidence. The basic model can be expanded to other cellular interactions. Conclusions These couplet cells and interacting couplet molecules can be viewed as a mechanism that provides a controlled and balanced division
Coupling GSM/ALE with ES-FEM-T3 for fluid-deformable structure interactions
NASA Astrophysics Data System (ADS)
Wang, S.; Khoo, B. C.; Liu, G. R.; Xu, G. X.; Chen, L.
2014-11-01
In light of the effectiveness of the edge-based smoothed finite element method (ES-FEM-T3) and arbitrary Lagrangian-Eulerian gradient smoothing method (GSM/ALE) in, respectively, solving the pure solid and fluid flow problems using three-node triangular elements, they are coupled together in the present study to solve the more challenging fluid-deformable structure interaction (FSI) problems based on the weak coupling algorithm. Specifically, the fluid flow is tracked over the moving mesh with the well developed GSM/ALE and the transient response of the solid part is solved by the newly developed explicit ES-FEM-T3. The solutions from these two parts are “linked” together by the carefully formulated FSI coupling conditions on the FSI interface. Detailed procedures are summarized to illustrate the implementations of the GSM/ALE with ES-FEM-T3 in an FSI analysis. Three benchmarks are employed to validate the proposed coupled smoothed method in solving both transient and steady-state FSI problems. The mesh sensitivity analysis is further carried out showing that the results of an FSI system appear more sensitive to the change in the solid mesh as compared to the fluid mesh, thus suggesting a more refined mesh for the solid part. Another significant finding is that the present method can still produce reliable results even on the extremely distorted mesh near the FSI interface. The successful coupling GSM/ALE with ES-FEM-T3 for solving FSI problems serves as a good start for further implementing the family of smoothed methods in solving more complex cross-area problems.
Time Delay Effect in a Living Coupled Oscillator System with the Plasmodium of Physarum polycephalum
NASA Astrophysics Data System (ADS)
Takamatsu, Atsuko; Fujii, Teruo; Endo, Isao
2000-08-01
A living coupled oscillator system was constructed by a cell patterning method with a plasmodial slime mold, in which parameters such as coupling strength and distance between the oscillators can be systematically controlled. Rich oscillation phenomena between the two-coupled oscillators, namely, desynchronizing and antiphase/in-phase synchronization were observed according to these parameters. Both experimental and theoretical approaches showed that these phenomena are closely related to the time delay effect in interactions between the oscillators.
Do the Naive Know Best? The Predictive Power of Naive Ratings of Couple Interactions
ERIC Educational Resources Information Center
Baucom, Katherine J. W.; Baucom, Brian R.; Christensen, Andrew
2012-01-01
We examined the utility of naive ratings of communication patterns and relationship quality in a large sample of distressed couples. Untrained raters assessed 10-min videotaped interactions from 134 distressed couples who participated in both problem-solving and social support discussions at each of 3 time points (pre-therapy, post-therapy, and…
Anizelli, Pedro R; Favaro, Denize C; Contreras, Rubén H; Tormena, Cláudio F
2011-06-01
In order to study the influence of hyperconjugative, inductive, steric, and hydrogen-bond interactions on (1)J(CF) and (2)J(CF) NMR spin-spin coupling constants (SSCCs), they were measured in cis- and trans-4-t-butyl-2-fluorocyclohexanones and their alcohol derivatives. The four isotropic terms of those SSCCs, Fermi contact (FC), spin dipolar (SD), paramagnetic spin-orbit (PSO), and diamagnetic spin-orbit (DSO), were calculated at the SOPPA(CCSD)/EPR-III level. Significant changes in FC and PSO terms along that series of compounds were rationalized in terms of their transmission mechanisms by employing a qualitative analysis of their expressions in terms of the polarization propagator formalism. The PSO term is found to be sensitive to proximate interactions like steric compression and hydrogen bonding; we describe how it could be used to gauge such interactions. The FC term of (2)J(CF) SSCC in cis-4-t-butyl-2-fluorocyclohexanone is rationalized as transmitted in part by the superposition of the F and O electronic clouds.
Strong interactive massive particles from a strong coupled theory
Khlopov, Maxim Yu.; Kouvaris, Chris
2008-03-15
Minimal walking technicolor models can provide a nontrivial solution for cosmological dark matter, if the lightest technibaryon is doubly charged. Technibaryon asymmetry generated in the early Universe is related to baryon asymmetry, and it is possible to create an excess of techniparticles with charge (-2). These excessive techniparticles are all captured by {sup 4}He, creating techni-O-helium tOHe atoms, as soon as {sup 4}He is formed in big bang nucleosynthesis. The interaction of techni-O-helium with nuclei opens new paths to the creation of heavy nuclei in big bang nucleosynthesis. Because of the large mass of technibaryons, the tOHe ''atomic'' gas decouples from the baryonic matter and plays the role of dark matter in large scale structure formation, while structures in small scales are suppressed. Nuclear interactions with matter slow down cosmic techni-O-helium in the Earth below the threshold of underground dark matter detectors, thus escaping severe cryogenic dark matter search constraints. On the other hand, these nuclear interactions are not sufficiently strong to exclude this form of strongly interactive massive particles by constraints from the XQC experiment. Experimental tests of this hypothesis are possible in the search for tOHe in balloon-borne experiments (or on the ground) and for its charged techniparticle constituents in cosmic rays and accelerators. The tOHe atoms can cause cold nuclear transformations in matter and might form anomalous isotopes, offering possible ways to exclude (or prove?) their existence.
Effective field theory of weakly coupled inflationary models
Gwyn, Rhiannon; Palma, Gonzalo A.; Sakellariadou, Mairi; Sypsas, Spyros E-mail: gpalmaquilod@ing.uchile.cl E-mail: spyridon.sypsas@kcl.ac.uk
2013-04-01
The application of Effective Field Theory (EFT) methods to inflation has taken a central role in our current understanding of the very early universe. The EFT perspective has been particularly useful in analyzing the self-interactions determining the evolution of co-moving curvature perturbations (Goldstone boson modes) and their influence on low-energy observables. However, the standard EFT formalism, to lowest order in spacetime differential operators, does not provide the most general parametrization of a theory that remains weakly coupled throughout the entire low-energy regime. Here we study the EFT formulation by including spacetime differential operators implying a scale dependence of the Goldstone boson self-interactions and its dispersion relation. These operators are shown to arise naturally from the low-energy interaction of the Goldstone boson with heavy fields that have been integrated out. We find that the EFT then stays weakly coupled all the way up to the cutoff scale at which ultraviolet degrees of freedom become operative. This opens up a regime of new physics where the dispersion relation is dominated by a quadratic dependence on the momentum ω ∼ p{sup 2}. In addition, provided that modes crossed the Hubble scale within this energy range, the predictions of inflationary observables — including non-Gaussian signatures — are significantly affected by the new scales characterizing it.
Dynamic nonlinear thermal optical effects in coupled ring resonators
NASA Astrophysics Data System (ADS)
Huang, Chenguang; Fan, Jiahua; Zhu, Lin
2012-09-01
We investigate the dynamic nonlinear thermal optical effects in a photonic system of two coupled ring resonators. A bus waveguide is used to couple light in and out of one of the coupled resonators. Based on the coupling from the bus to the resonator, the coupling between the resonators and the intrinsic loss of each individual resonator, the system transmission spectrum can be classified by three different categories: coupled-resonator-induced absorption, coupled-resonator-induced transparency and over coupled resonance splitting. Dynamic thermal optical effects due to linear absorption have been analyzed for each category as a function of the input power. The heat power in each resonator determines the thermal dynamics in this coupled resonator system. Multiple "shark fins" and power competition between resonators can be foreseen. Also, the nonlinear absorption induced thermal effects have been discussed.
Incoherent chimera and glassy states in coupled oscillators with frustrated interactions
NASA Astrophysics Data System (ADS)
Choe, Chol-Ung; Ri, Ji-Song; Kim, Ryong-Son
2016-09-01
We suggest a site disorder model that describes the population of identical oscillators with quenched random interactions for both the coupling strength and coupling phase. We obtain the reduced equations for the suborder parameters, on the basis of Ott-Antonsen ansatz theory, and present a complete bifurcation analysis of the reduced system. New effects include the appearance of the incoherent chimera and glassy state, both of which are caused by heterogeneity of the coupling phases. In the incoherent chimera state, the system displays an exotic symmetry-breaking behavior in spite of the apparent structural symmetry where the oscillators for both of the two subpopulations are in a frustrated state, while the phase distribution for each subpopulation approaches a steady state that differs from each other. When the incoherent chimera undergoes Hopf bifurcation, the system displays a breathing incoherent chimera. The glassy state that occurs on a surface of three-dimensional parameter space exhibits a continuum of metastable states with zero value of the global order parameter. Explicit formulas are derived for the system's Hopf, saddle-node, and transcritical bifurcation curves, as well as the codimension-2 crossing points, including the Takens-Bogdanov point.
Self-interacting asymmetric dark matter coupled to a light massive dark photon
Petraki, Kalliopi; Pearce, Lauren; Kusenko, Alexander E-mail: lpearce@ucla.edu
2014-07-01
Dark matter (DM) with sizeable self-interactions mediated by a light species offers a compelling explanation of the observed galactic substructure; furthermore, the direct coupling between DM and a light particle contributes to the DM annihilation in the early universe. If the DM abundance is due to a dark particle-antiparticle asymmetry, the DM annihilation cross-section can be arbitrarily large, and the coupling of DM to the light species can be significant. We consider the case of asymmetric DM interacting via a light (but not necessarily massless) Abelian gauge vector boson, a dark photon. In the massless dark photon limit, gauge invariance mandates that DM be multicomponent, consisting of positive and negative dark ions of different species which partially bind in neutral dark atoms. We argue that a similar conclusion holds for light dark photons; in particular, we establish that the multi-component and atomic character of DM persists in much of the parameter space where the dark photon is sufficiently light to mediate sizeable DM self-interactions. We discuss the cosmological sequence of events in this scenario, including the dark asymmetry generation, the freeze-out of annihilations, the dark recombination and the phase transition which gives mass to the dark photon. We estimate the effect of self-interactions in DM haloes, taking into account this cosmological history. We place constraints based on the observed ellipticity of large haloes, and identify the regimes where DM self-scattering can affect the dynamics of smaller haloes, bringing theory in better agreement with observations. Moreover, we estimate the cosmological abundance of dark photons in various regimes, and derive pertinent bounds.
Modelling Tropical Cyclones-Ocean interactions: the role of the Atmophere - Ocean coupling frequency
NASA Astrophysics Data System (ADS)
Scoccimarro, Enrico; Fogli, Pier Giuseppe; Gualdi, Silvio; Masina, Simona; Navarra, Antonio
2016-04-01
The interaction between Tropical Cyclones (TCs) and ocean is a major mechanism responsible for energy exchange between the atmosphere and the ocean. TCs affect the thermal and dynamical structure of the ocean, but the magnitude of the impact is still uncertain. Very few CMIP5 models demonstrated ability in representing TCs, mainly due to their horizontal resolution. We aim to improve TCs representation in next CMIPs experiments through the new CMCC-CM2VHR General Circulation Model, having a horizontal resolution of 1/4 degree in both atmospheric and ocean components. The model is capable to represent realistically TCs up to Cat-5 Typhoons. A good representation of the TC-Ocean interaction strongly depends on the coupling frequency between the atmospheric and the ocean components. In this work, we found that a better representation of the negative Sea Surface Temperature - TC induced feedback, through a high (hourly) coupling frequency, ensures the reduction of the TC induced Power Dissipation Index (PDI) bias of one order of magnitude. In addition, a cat-5 storm case study is deeply investigated also in terms of TC effects on the deep ocean.
Computations with near-field coupled plasmon particles interacting with phase-change materials
NASA Astrophysics Data System (ADS)
Kanazawa, Shohei; Kuwamura, Kenta; Kihara, Yuya; Hirukawa, Yusuke; Saiki, Toshiharu
2015-12-01
The computing functionality emerging from spatial correlations due to near-field interactions between local processing and memory elements is discussed. In particular, we investigate the possibility of solving a problem analogous to the spin-glass problem by using a coupled dipole system, in which the individual coupling strengths can be modified to optimize the system so that the exact solution can be easily reached. For this algorithm, we propose an implementation based on a coupled plasmon-particle system interacting with a phase-change material; this system exhibits threshold behavior and plasticity to provide processing and memory functions, respectively.
NASA Astrophysics Data System (ADS)
Wang, Luo; Rui, Li; Zhiqiang, Gai; RuiBo, Ai; Hongmin, Zhang; Xiaomei, Zhang; Bing, Yan
2016-07-01
Lead oxide (PbO), which plays the key roles in a range of research fields, has received a great deal of attention. Owing to the large density of electronic states and heavy atom Pb including in PbO, the excited states of the molecule have not been well studied. In this work, high level multireference configuration interaction calculations on the low-lying states of PbO have been carried out by utilizing the relativistic effective core potential. The effects of the core-valence correlation correction, the Davidson modification, and the spin-orbital coupling on the electronic structure of the PbO molecule are estimated. The potential energy curves of 18 Λ-S states correlated to the lowest dissociation limit (Pb (3Pg) + O(3Pg)) are reported. The calculated spectroscopic parameters of the electronic states below 30000 cm-1, for instance, X1Σ+, 13Σ+, and 13Σ-, and their spin-orbit coupling interaction, are compared with the experimental results, and good agreements are derived. The dipole moments of the 18 Λ-S states are computed with the configuration interaction method, and the calculated dipole moments of X1Σ+ and 13Σ+ are consistent with the previous experimental results. The transition dipole moments from 11Π, 21Π, and 21Σ+ to X1Σ+ and other singlet excited states are estimated. The radiative lifetime of several low-lying vibrational levels of 11Π, 21Π, and 21Σ+ states are evaluated. Project supported by the National Natural Science Foundation of China (Grant Nos. 11404180 and 11574114), the Natural Science Foundation of Heilongjiang Province, China (Grant No. A2015010), the University Nursing Program for Young Scholars with Creative Talents in Heilongjiang Province, China (Grant No. UNPYSCT-2015095), and the Natural Science Foundation of Jilin Province, China (Grant No. 20150101003JC).
NASA Astrophysics Data System (ADS)
Wang, Luo; Rui, Li; Zhiqiang, Gai; RuiBo, Ai; Hongmin, Zhang; Xiaomei, Zhang; Bing, Yan
2016-07-01
Lead oxide (PbO), which plays the key roles in a range of research fields, has received a great deal of attention. Owing to the large density of electronic states and heavy atom Pb including in PbO, the excited states of the molecule have not been well studied. In this work, high level multireference configuration interaction calculations on the low-lying states of PbO have been carried out by utilizing the relativistic effective core potential. The effects of the core-valence correlation correction, the Davidson modification, and the spin–orbital coupling on the electronic structure of the PbO molecule are estimated. The potential energy curves of 18 Λ-S states correlated to the lowest dissociation limit (Pb (3Pg) + O(3Pg)) are reported. The calculated spectroscopic parameters of the electronic states below 30000 cm‑1, for instance, X1Σ+, 13Σ+, and 13Σ‑, and their spin–orbit coupling interaction, are compared with the experimental results, and good agreements are derived. The dipole moments of the 18 Λ-S states are computed with the configuration interaction method, and the calculated dipole moments of X1Σ+ and 13Σ+ are consistent with the previous experimental results. The transition dipole moments from 11Π, 21Π, and 21Σ+ to X1Σ+ and other singlet excited states are estimated. The radiative lifetime of several low-lying vibrational levels of 11Π, 21Π, and 21Σ+ states are evaluated. Project supported by the National Natural Science Foundation of China (Grant Nos. 11404180 and 11574114), the Natural Science Foundation of Heilongjiang Province, China (Grant No. A2015010), the University Nursing Program for Young Scholars with Creative Talents in Heilongjiang Province, China (Grant No. UNPYSCT-2015095), and the Natural Science Foundation of Jilin Province, China (Grant No. 20150101003JC).
Semantic Interaction for Visual Analytics: Toward Coupling Cognition and Computation
Endert, Alexander
2014-07-01
The dissertation discussed in this article [1] was written in the midst of an era of digitization. The world is becoming increasingly instrumented with sensors, monitoring, and other methods for generating data describing social, physical, and natural phenomena. Thus, data exist with the potential of being analyzed to uncover, or discover, the phenomena from which it was created. However, as the analytic models leveraged to analyze these data continue to increase in complexity and computational capability, how can visualizations and user interaction methodologies adapt and evolve to continue to foster discovery and sensemaking?
A coupled hidden Markov model for disease interactions.
Sherlock, Chris; Xifara, Tatiana; Telfer, Sandra; Begon, Mike
2013-08-01
To investigate interactions between parasite species in a host, a population of field voles was studied longitudinally, with presence or absence of six different parasites measured repeatedly. Although trapping sessions were regular, a different set of voles was caught at each session, leading to incomplete profiles for all subjects. We use a discrete time hidden Markov model for each disease with transition probabilities dependent on covariates via a set of logistic regressions. For each disease the hidden states for each of the other diseases at a given time point form part of the covariate set for the Markov transition probabilities from that time point. This allows us to gauge the influence of each parasite species on the transition probabilities for each of the other parasite species. Inference is performed via a Gibbs sampler, which cycles through each of the diseases, first using an adaptive Metropolis-Hastings step to sample from the conditional posterior of the covariate parameters for that particular disease given the hidden states for all other diseases and then sampling from the hidden states for that disease given the parameters. We find evidence for interactions between several pairs of parasites and of an acquired immune response for two of the parasites. PMID:24223436
A coupled hidden Markov model for disease interactions.
Sherlock, Chris; Xifara, Tatiana; Telfer, Sandra; Begon, Mike
2013-08-01
To investigate interactions between parasite species in a host, a population of field voles was studied longitudinally, with presence or absence of six different parasites measured repeatedly. Although trapping sessions were regular, a different set of voles was caught at each session, leading to incomplete profiles for all subjects. We use a discrete time hidden Markov model for each disease with transition probabilities dependent on covariates via a set of logistic regressions. For each disease the hidden states for each of the other diseases at a given time point form part of the covariate set for the Markov transition probabilities from that time point. This allows us to gauge the influence of each parasite species on the transition probabilities for each of the other parasite species. Inference is performed via a Gibbs sampler, which cycles through each of the diseases, first using an adaptive Metropolis-Hastings step to sample from the conditional posterior of the covariate parameters for that particular disease given the hidden states for all other diseases and then sampling from the hidden states for that disease given the parameters. We find evidence for interactions between several pairs of parasites and of an acquired immune response for two of the parasites.
Finite Element Modeling of Non-linear Coupled Interacting Fault System
NASA Astrophysics Data System (ADS)
Xing, H. L.; Zhang, J.; Wyborn, D.
2009-04-01
coupled fluid effects and the geomechanical energy conversion for the pure/coupled thermal analysis. • Pandas/Fluid is a finite element method based module for simulating the fluid flow in the fractured porous media; the fluid flow velocity and pressure are calculated from energy equilibrium equations without/together with the coupling effects of the thermal and solid rock deformation for an independent/coupled fluid flow analysis; • Pandas/Post is to visualise the simulation results through the integration of VTK and/or Patran. All the above modules can be used independently/together to simulate individual/coupled phenomena (such as interacting fault system dynamics, heat flow and fluid flow) without/with coupling effects. PANDAS has been applied to the following issues: • visualisation of the microseismic events to monitor and determine where/how the underground rupture proceeds during a hydraulic stimulation, to generate the mesh using the recorded data for determining the domain of the ruptured zone and to evaluate the material parameters (i.e. the permeability) for the further numerical analysis; • interacting fault system simulation to determine the relevant complicated dynamic rupture process. • geomechanical-fluid flow coupling analysis to investigate the interactions between fluid flow and deformation in the fractured porous media under different loading conditions. • thermo-fluid flow coupling analysis of a fractured geothermal reservoir system. PANDAS will be further developed for a multiscale simulation of multiphase dynamic behaviour for a certain fractured geothermal reservoir. More details and additional application examples will be given during the presentation. References [1] Xing, H. L., Makinouchi, A. and Mora, P. (2007). Finite element modeling of interacting fault system, Physics of the Earth and Planetary Interiors, 163, 106-121.doi:10.1016/j.pepi.2007.05.006 [2] Xing, H. L., Mora, P., Makinouchi, A. (2006). An unified friction
Unified theory of effective interaction
NASA Astrophysics Data System (ADS)
Takayanagi, Kazuo
2016-09-01
We present a unified description of effective interaction theories in both algebraic and graphic representations. In our previous work, we have presented the Rayleigh-Schrödinger and Bloch perturbation theories in a unified fashion by introducing the main frame expansion of the effective interaction. In this work, we start also from the main frame expansion, and present various nonperturbative theories in a coherent manner, which include generalizations of the Brandow, Brillouin-Wigner, and Bloch-Horowitz theories on the formal side, and the extended Krenciglowa-Kuo and the extended Lee-Suzuki methods on the practical side. We thus establish a coherent and comprehensive description of both perturbative and nonperturbative theories on the basis of the main frame expansion.
NASA Astrophysics Data System (ADS)
Sun, Kuei; Qu, Chunlei; Xu, Yong; Zhang, Yongping; Zhang, Chuanwei
Spin-orbit (SO) coupling plays a major role in many important phenomena in condensed matter physics. However, the SO coupling physics in high-spin systems, especially with superfluids, has not been well explored because of the spin half of electrons in solids. In this context, the recent experimental realization of spin-orbit coupling in spin-1 Bose-Einstein condensates (BECs) has opened a completely new avenue for exploring SO-coupled high-spin superfluids. Nevertheless, the experiment has only revealed the single-particle physics of the system. Here, we study the effects of interactions between atoms on the ground states and collective excitations of SO-coupled spin-1 BECs in the presence of a spin-tensor potential. We find that ferromagnetic interaction between atoms can induce a stripe phase exhibiting two modulating patterns. We characterize the phase transitions between different phases using the spin-tensor density as well as the collective dipole motion of the BEC. We show that there exists a new type of double maxon-roton structure in the Bogoliubov-excitation spectrum, attributing to the three band minima of the SO-coupled spin-1 BEC. Our work could motivate further theoretical and experimental study along this direction.
Effective interactions between fluid membranes.
Lu, Bing-Sui; Podgornik, Rudolf
2015-08-01
A self-consistent theory is proposed for the general problem of interacting undulating fluid membranes subject to the constraint that they do not interpenetrate. We implement the steric constraint via an exact functional integral representation and, through the use of a saddle-point approximation, transform it into a novel effective steric potential. The steric potential is found to consist of two contributions: one generated by zero-mode fluctuations of the membranes and the other by thermal bending fluctuations. For membranes of cross-sectional area S, we find that the bending fluctuation part scales with the intermembrane separation d as d-2 for d≪√S but crosses over to d-4 scaling for d≫√S, whereas the zero-mode part of the steric potential always scales as d-2. For membranes interacting exclusively via the steric potential, we obtain closed-form expressions for the effective interaction potential and for the rms undulation amplitude σ, which becomes small at low temperatures T and/or large bending stiffnesses κ. Moreover, σ scales as d for d≪√S but saturates at √kBTS/κ for d≫√S. In addition, using variational Gaussian theory, we apply our self-consistent treatment to study intermembrane interactions subject to different types of potentials: (i) the Moreira-Netz potential for a pair of strongly charged membranes with an intervening solution of multivalent counterions, (ii) an attractive square well, (iii) the Morse potential, and (iv) a combination of hydration and van der Waals interactions. PMID:26382349
Effective interactions between fluid membranes
NASA Astrophysics Data System (ADS)
Lu, Bing-Sui; Podgornik, Rudolf
2015-08-01
A self-consistent theory is proposed for the general problem of interacting undulating fluid membranes subject to the constraint that they do not interpenetrate. We implement the steric constraint via an exact functional integral representation and, through the use of a saddle-point approximation, transform it into a novel effective steric potential. The steric potential is found to consist of two contributions: one generated by zero-mode fluctuations of the membranes and the other by thermal bending fluctuations. For membranes of cross-sectional area S , we find that the bending fluctuation part scales with the intermembrane separation d as d-2 for d ≪√{S } but crosses over to d-4 scaling for d ≫√{S } , whereas the zero-mode part of the steric potential always scales as d-2. For membranes interacting exclusively via the steric potential, we obtain closed-form expressions for the effective interaction potential and for the rms undulation amplitude σ , which becomes small at low temperatures T and/or large bending stiffnesses κ . Moreover, σ scales as d for d ≪√{S } but saturates at √{kBT S /κ } for d ≫√{S } . In addition, using variational Gaussian theory, we apply our self-consistent treatment to study intermembrane interactions subject to different types of potentials: (i) the Moreira-Netz potential for a pair of strongly charged membranes with an intervening solution of multivalent counterions, (ii) an attractive square well, (iii) the Morse potential, and (iv) a combination of hydration and van der Waals interactions.
Resonant atom-field interaction in large-size coupled-cavity arrays
Ciccarello, Francesco
2011-04-15
We consider an array of coupled cavities with staggered intercavity couplings, where each cavity mode interacts with an atom. In contrast to large-size arrays with uniform hopping rates where the atomic dynamics is known to be frozen in the strong-hopping regime, we show that resonant atom-field dynamics with significant energy exchange can occur in the case of staggered hopping rates even in the thermodynamic limit. This effect arises from the joint emergence of an energy gap in the free photonic dispersion relation and a discrete frequency at the gap's center. The latter corresponds to a bound normal mode stemming solely from the finiteness of the array length. Depending on which cavity is excited, either the atomic dynamics is frozen or a Jaynes-Cummings-like energy exchange is triggered between the bound photonic mode and its atomic analog. As these phenomena are effective with any number of cavities, they are prone to be experimentally observed even in small-size arrays.
NASA Astrophysics Data System (ADS)
Ruhman, Jonathan; Altman, Ehud
2014-03-01
Majorana zero modes can emerge at the edge of a nano wire subject to Rashba like spin-orbit interaction and a Zeeman field, which is coupled through a proximity effect to an s-wave superconductor. Can the zero modes obtain even if the superconductivity is intrinsic, due to attractive interactions in the single channel wire, with strictly conserved charge? We answer this question in the affirmative and provide an exact low energy description of the Majorana modes at the interface between a low density ``trivial'' Luttinger liquid on one side and a high density ``topological'' Luttinger liquid on the other side. The energy splitting of a pair of such modes at the edges of a topological segment of length L scales as 1 /L K / 2 where K > 1 is the Luttinger parameter. We discuss how to detect these Majorana modes in systems of ultra cold atoms, where an intrinsic attractive interaction is indeed much more natural than proximity induced pairing. Supported by ERC Synergy grant UQUAM.
Ellis, Benjamin H; Aggarwal, Somil; Chakraborty, Arindam
2016-01-12
Multicomponent systems are defined as chemical systems that require a quantum mechanical description of two or more different types of particles. Non-Born-Oppenheimer electron-nuclear interactions in molecules, electron-hole interactions in electronically excited nanoparticles, and electron-positron interactions are examples of physical systems that require a multicomponent quantum mechanical formalism. The central challenge in the theoretical treatment of multicomponent systems is capturing the many-body correlation effects that exist not only between particles of identical types (electron-electron) but also between particles of different types (electron-nuclear and electron-hole). In this work, the development and implementation of multicomponent coupled-cluster (mcCC) theory for treating particle-particle correlation in multicomponent systems are presented. This method provides a balanced treatment of many-particle correlation effects in a general multicomponent system while maintaining a size-consistent and size-extensive formalism. The coupled-cluster ansatz presented here is an extension of the electronic structure CCSD formulation for multicomponent systems and is defined as |ΨmcCC⟩ = eT1I+T2I+T1II+T2II+T11I,II+T12I,II+T21I,II+T22I,II|0I0II⟩. The cluster amplitudes in the mcCC wave function were obtained by projecting the mcCC Schrödinger equation onto a direct product space of singly and doubly excited states of type I and II particles and then solving the resulting mcCC equations iteratively. These equations were derived using an automated application of the generalized Wick’s theorem and were implemented using a computer-assisted source code generation approach. The applicability of the mcCC method was demonstrated by calculating ground state energies of multicomponent Hooke's atom and positronium hydride systems as well as by calculating exciton and biexciton binding energies in multiexcitonic systems. For each case, the mcCC results were
Giant coupling effect between metal nanoparticle chain and optical waveguide.
Février, Mickaël; Gogol, Philippe; Aassime, Abdelhanin; Mégy, Robert; Delacour, Cécile; Chelnokov, Alexei; Apuzzo, Aniello; Blaize, Sylvain; Lourtioz, Jean-Michel; Dagens, Béatrice
2012-02-01
We demonstrate that the optical energy carried by a TE dielectric waveguide mode can be totally transferred into a transverse plasmon mode of a coupled metal nanoparticle chain. Experiments are performed at 1.5 μm. Mode coupling occurs through the evanescent field of the dielectric waveguide mode. Giant coupling effects are evidenced from record coupling lengths as short as ~560 nm. This result opens the way to nanometer scale devices based on localized plasmons in photonic integrated circuits. PMID:22251002
Laser-material interactions: A study of laser energy coupling with solids
Shannon, M A
1993-11-01
This study of laser-light interactions with solid materials ranges from low-temperature heating to explosive, plasma-forming reactions. Contained are four works concerning laser-energy coupling: laser (i) heating and (ii) melting monitored using a mirage effect technique, (iii) the mechanical stress-power generated during high-powered laser ablation, and (iv) plasma-shielding. First, a photothermal deflection (PTD) technique is presented for monitoring heat transfer during modulated laser heating of opaque solids that have not undergone phase-change. Of main interest is the physical significance of the shape, magnitude, and phase for the temporal profile of the deflection signal. Considered are the effects that thermophysical properties, boundary conditions, and geometry of the target and optical probe-beam have on the deflection response. PTD is shown to monitor spatial and temporal changes in heat flux leaving the surface due to changes in laser energy coupling. The PTD technique is then extended to detect phase-change at the surface of a solid target. Experimental data shows the onset of melt for indium and tin targets. The conditions for which melt can be detected by PTD is analyzed in terms of geometry, incident power and pulse length, and thermophysical properties of the target and surroundings. Next, monitoring high-powered laser ablation of materials with stress-power is introduced. The motivation for considering stress-power is given, followed by a theoretical discussion of stress-power and how it is determined experimentally. Experiments are presented for the ablation of aluminum targets as a function of energy and intensity. The stress-power response is analyzed for its physical significance. Lastly, the influence of plasma-shielding during high-powered pulsed laser-material interactions is considered. Crater size, emission, and stress-power are measured to determine the role that the gas medium and laser pulse length have on plasma shielding.
NASA Technical Reports Server (NTRS)
Mei, Chuh; Pates, Carl S., III
1994-01-01
A coupled boundary element (BEM)-finite element (FEM) approach is presented to accurately model structure-acoustic interaction systems. The boundary element method is first applied to interior, two and three-dimensional acoustic domains with complex geometry configurations. Boundary element results are very accurate when compared with limited exact solutions. Structure-interaction problems are then analyzed with the coupled FEM-BEM method, where the finite element method models the structure and the boundary element method models the interior acoustic domain. The coupled analysis is compared with exact and experimental results for a simplistic model. Composite panels are analyzed and compared with isotropic results. The coupled method is then extended for random excitation. Random excitation results are compared with uncoupled results for isotropic and composite panels.
Mirroring and beyond: coupled dynamics as a generalized framework for modelling social interactions
Hasson, Uri; Frith, Chris D.
2016-01-01
When people observe one another, behavioural alignment can be detected at many levels, from the physical to the mental. Likewise, when people process the same highly complex stimulus sequences, such as films and stories, alignment is detected in the elicited brain activity. In early sensory areas, shared neural patterns are coupled to the low-level properties of the stimulus (shape, motion, volume, etc.), while in high-order brain areas, shared neural patterns are coupled to high-levels aspects of the stimulus, such as meaning. Successful social interactions require such alignments (both behavioural and neural), as communication cannot occur without shared understanding. However, we need to go beyond simple, symmetric (mirror) alignment once we start interacting. Interactions are dynamic processes, which involve continuous mutual adaptation, development of complementary behaviour and division of labour such as leader–follower roles. Here, we argue that interacting individuals are dynamically coupled rather than simply aligned. This broader framework for understanding interactions can encompass both processes by which behaviour and brain activity mirror each other (neural alignment), and situations in which behaviour and brain activity in one participant are coupled (but not mirrored) to the dynamics in the other participant. To apply these more sophisticated accounts of social interactions to the study of the underlying neural processes we need to develop new experimental paradigms and novel methods of data analysis PMID:27069044
Mirroring and beyond: coupled dynamics as a generalized framework for modelling social interactions.
Hasson, Uri; Frith, Chris D
2016-05-01
When people observe one another, behavioural alignment can be detected at many levels, from the physical to the mental. Likewise, when people process the same highly complex stimulus sequences, such as films and stories, alignment is detected in the elicited brain activity. In early sensory areas, shared neural patterns are coupled to the low-level properties of the stimulus (shape, motion, volume, etc.), while in high-order brain areas, shared neural patterns are coupled to high-levels aspects of the stimulus, such as meaning. Successful social interactions require such alignments (both behavioural and neural), as communication cannot occur without shared understanding. However, we need to go beyond simple, symmetric (mirror) alignment once we start interacting. Interactions are dynamic processes, which involve continuous mutual adaptation, development of complementary behaviour and division of labour such as leader-follower roles. Here, we argue that interacting individuals are dynamically coupled rather than simply aligned. This broader framework for understanding interactions can encompass both processes by which behaviour and brain activity mirror each other (neural alignment), and situations in which behaviour and brain activity in one participant are coupled (but not mirrored) to the dynamics in the other participant. To apply these more sophisticated accounts of social interactions to the study of the underlying neural processes we need to develop new experimental paradigms and novel methods of data analysis. PMID:27069044
Quantum jumps and spin dynamics of interacting atoms in a strongly coupled atom-cavity system.
Khudaverdyan, M; Alt, W; Kampschulte, T; Reick, S; Thobe, A; Widera, A; Meschede, D
2009-09-18
We experimentally investigate the spin dynamics of one and two neutral atoms strongly coupled to a high finesse optical cavity. We observe quantum jumps between hyperfine ground states of a single atom. The interaction-induced normal-mode splitting of the atom-cavity system is measured via the atomic excitation. Moreover, we observe the mutual influence of two atoms simultaneously coupled to the cavity mode.
NASA Astrophysics Data System (ADS)
Li, Qian-Shu; Shi, Jian-Cheng
2007-01-01
Two unidirectional coupled brusselator systems, subject to common and uncorrelated multiplicative noise, are investigated, respectively. It can be found that, the parameter heterogeneity effect may be destroyed above critical coupling strength. Synchronization occurs between subsystems subjected to common noise, but cannot achieve by means of uncorrelated noise.
SU(2) Higher-order effective quark interactions from polarization
NASA Astrophysics Data System (ADS)
Braghin, Fábio L.
2016-10-01
Higher order quark effective interactions are found for SU(2) flavor by departing from a non-local quark-quark interaction. By integrating out a component of the quark field, the determinant is expanded in chirally symmetric and symmetry breaking effective interactions up to the fifth order in the quark bilinears. The resulting coupling constants are resolved in the leading order of the longwavelength limit and exact numerical ratios between several of these coupling constants are obtained in the large quark mass limit. In this level, chiral invariant interactions only show up in even powers of the quark bilinears, i.e. O(ψ bar ψ) 2 n (n = 1 , 2 , 3 , . .), whereas (explicit) chiral symmetry breaking terms emerge as O(ψ bar ψ) n being always proportional to some power of the Lagrangian quark mass.
The Thirring interaction in the two-dimensional axial-current-pseudoscalar derivative coupling model
Belvedere, L.V. . E-mail: armflavio@if.uff.br
2006-12-15
We reexamine the two-dimensional model of massive fermions interacting with a massless pseudoscalar field via axial-current derivative coupling. The hidden Thirring interaction in the axial-derivative coupling model is exhibited compactly by performing a canonical field transformation on the Bose field algebra and the model is mapped into the Thirring model with an additional vector-current-scalar derivative interaction (Schroer-Thirring model). The Fermi field operator is rewritten in terms of the Mandelstam soliton operator coupled to a free massless scalar field. The charge sectors of the axial-derivative model are mapped into the charge sectors of the massive Thirring model. The complete bosonized version of the model is presented. The bosonized composite operators of the quantum Hamiltonian are obtained as the leading operators in the Wilson short distance expansions.
A state interaction spin-orbit coupling density matrix renormalization group method.
Sayfutyarova, Elvira R; Chan, Garnet Kin-Lic
2016-06-21
We describe a state interaction spin-orbit (SISO) coupling method using density matrix renormalization group (DMRG) wavefunctions and the spin-orbit mean-field (SOMF) operator. We implement our DMRG-SISO scheme using a spin-adapted algorithm that computes transition density matrices between arbitrary matrix product states. To demonstrate the potential of the DMRG-SISO scheme we present accurate benchmark calculations for the zero-field splitting of the copper and gold atoms, comparing to earlier complete active space self-consistent-field and second-order complete active space perturbation theory results in the same basis. We also compute the effects of spin-orbit coupling on the spin-ladder of the iron-sulfur dimer complex [Fe2S2(SCH3)4](3-), determining the splitting of the lowest quartet and sextet states. We find that the magnitude of the zero-field splitting for the higher quartet and sextet states approaches a significant fraction of the Heisenberg exchange parameter. PMID:27334156
A state interaction spin-orbit coupling density matrix renormalization group method
NASA Astrophysics Data System (ADS)
Sayfutyarova, Elvira R.; Chan, Garnet Kin-Lic
2016-06-01
We describe a state interaction spin-orbit (SISO) coupling method using density matrix renormalization group (DMRG) wavefunctions and the spin-orbit mean-field (SOMF) operator. We implement our DMRG-SISO scheme using a spin-adapted algorithm that computes transition density matrices between arbitrary matrix product states. To demonstrate the potential of the DMRG-SISO scheme we present accurate benchmark calculations for the zero-field splitting of the copper and gold atoms, comparing to earlier complete active space self-consistent-field and second-order complete active space perturbation theory results in the same basis. We also compute the effects of spin-orbit coupling on the spin-ladder of the iron-sulfur dimer complex [Fe2S2(SCH3)4]3-, determining the splitting of the lowest quartet and sextet states. We find that the magnitude of the zero-field splitting for the higher quartet and sextet states approaches a significant fraction of the Heisenberg exchange parameter.
A state interaction spin-orbit coupling density matrix renormalization group method.
Sayfutyarova, Elvira R; Chan, Garnet Kin-Lic
2016-06-21
We describe a state interaction spin-orbit (SISO) coupling method using density matrix renormalization group (DMRG) wavefunctions and the spin-orbit mean-field (SOMF) operator. We implement our DMRG-SISO scheme using a spin-adapted algorithm that computes transition density matrices between arbitrary matrix product states. To demonstrate the potential of the DMRG-SISO scheme we present accurate benchmark calculations for the zero-field splitting of the copper and gold atoms, comparing to earlier complete active space self-consistent-field and second-order complete active space perturbation theory results in the same basis. We also compute the effects of spin-orbit coupling on the spin-ladder of the iron-sulfur dimer complex [Fe2S2(SCH3)4](3-), determining the splitting of the lowest quartet and sextet states. We find that the magnitude of the zero-field splitting for the higher quartet and sextet states approaches a significant fraction of the Heisenberg exchange parameter.
Quantum dissipative effect of one dimension coupled anharmonic oscillator
Sulaiman, A.; Zen, Freddy P.
2015-04-16
Quantum dissipative effect of one dimension coupled anharmonic oscillator is investigated. The systems are two coupled harmonic oscillator with the different masses. The dissipative effect is studied based on the quantum state diffusion formalism. The result show that the anharmonic effect increase the amplitude but the lifetime of the oscillation depend on the damping coefficient and do not depend on the temperature.
Response of different regional online coupled models to aerosol-radiation interactions
NASA Astrophysics Data System (ADS)
Forkel, Renate; Balzarini, Alessandra; Brunner, Dominik; Baró, Rocio; Curci, Gabriele; Hirtl, Marcus; Honzak, Luka; Jiménez-Guerrero, Pedro; Jorba, Oriol; Pérez, Juan L.; Pirovano, Guido; San José, Roberto; Schröder, Wolfram; Tuccella, Paolo; Werhahn, Johannes; Wolke, Ralf; Žabkar, Rahela
2016-04-01
The importance of aerosol-meteorology interactions and their representation in online coupled regional atmospheric chemistry-meteorology models was investigated in COST Action ES1004 (EuMetChem, http://eumetchem.info/). Case study results from different models (COSMO-Muscat, COSMO-ART, and different configurations of WRF-Chem), which were applied for Europe as a coordinated exercise for the year 2010, are analyzed with respect to inter-model variability and the response of the different models to direct and indirect aerosol-radiation interactions. The main focus was on two episodes - the Russian heat wave and wildfires episode in July/August 2010 and a period in October 2010 with enhanced cloud cover and rain and including an of Saharan dust transport to Europe. Looking at physical plausibility the decrease in downward solar radiation and daytime temperature due to the direct aerosol effect is robust for all model configurations. The same holds for the pronounced decrease in cloud water content and increase in solar radiation for cloudy conditions and very low aerosol concentrations that was found for WRF-Chem when aerosol cloud interactions were considered. However, when the differences were tested for statistical significance no significant differences in mean solar radiation and mean temperature between the baseline case and the simulations including the direct and indirect effect from simulated aerosol concentrations were found over Europe for the October episode. Also for the fire episode differences between mean temperature and radiation from the simulations with and without the direct aerosol effect were not significant for the major part of the modelling domain. Only for the region with high fire emissions in Russia, the differences in mean solar radiation and temperature due to the direct effect were found to be significant during the second half of the fire episode - however only for a significance level of 0.1. The few observational data indicate that
Spin-orbit coupled weakly interacting Bose-Einstein condensates in harmonic traps.
Hu, Hui; Ramachandhran, B; Pu, Han; Liu, Xia-Ji
2012-01-01
We investigate theoretically the phase diagram of a spin-orbit coupled Bose gas in two-dimensional harmonic traps. We show that at strong spin-orbit coupling the single-particle spectrum decomposes into different manifolds separated by ℏω{⊥}, where ω{⊥} is the trapping frequency. For a weakly interacting gas, quantum states with Skyrmion lattice patterns emerge spontaneously and preserve either parity symmetry or combined parity-time-reversal symmetry. These phases can be readily observed in a spin-orbit coupled gas of ^{87}Rb atoms in a highly oblate trap. PMID:22304247
Effective Student Learning of Fractions with an Interactive Simulation
ERIC Educational Resources Information Center
Hensberry, Karina K. R.; Moore, Emily B.; Perkins, Katherine K.
2015-01-01
Computer technology, when coupled with reform-based teaching practices, has been shown to be an effective way to support student learning of mathematics. The quality of the technology itself, as well as how it is used, impacts how much students learn. Interactive simulations are dynamic virtual environments similar to virtual manipulatives that…
Quasiconfigurations and the theory of effective interactions
NASA Astrophysics Data System (ADS)
Poves, A.; Zuker, A.
1981-05-01
Perturbation theory is reformulated. Schrödinger's equation is recast as a non linear integral equation which yields by Neumann expansion a linked cluster series for the degenerate, quasi degenerate or non degenerate problem. An effective interaction theory emerges that can be formulated in a biorthogonal basis leading to a non Hermitian secular problem. Hermiticity can be recovered in a clear and rigorous way. As the mathematical form of the theory is dictated by the request of physical clarity the latter is obtained naturally. When written in diagrammatic many body language, the integral equation produces a set of linked coupled equations for the degenerate case. The classic summations (Brueckner, Bethe-Faddeev and RPA) emerge naturally. Possible extensions of nuclear matter theory are suggested.
A facile way to realize exchange coupling interaction in hard/soft magnetic composites
NASA Astrophysics Data System (ADS)
Li, Dongyun; Wang, Fan; Xia, Ailin; Zhang, Lijiao; Li, Tingting; Jin, Chuangui; Liu, Xianguo
2016-11-01
SrFe12O19/CoFe2O4 and SrFe12O19/Fe-B hard/soft magnetic composites were obtained by using powders synthesized via a hydrothermal and a molten salt method, respectively. The exchange coupling interaction was found to exist in the composites after a facile grinding according to the results of magnetic hysteresis loops and irreversible sloping recoil loops. It can be found that different grinding time affects their magnetic properties slightly. Our study proves that the conditions of realizing exchange coupling interaction may not be so stringent.
Spatio-temporal coupling of random electromagnetic pulses interacting with reflecting gratings.
Yao, Min; Cai, Yangjian; Korotkova, Olga; Lin, Qiang; Wang, Zhaoying
2010-10-11
Matrix optics is applied to a class of random, in time and space, electromagnetic pulsed beam-like (REMPB) radiation interacting with linear optical elements. A 6×6 order matrix describing transformation of a six-dimensional state vector including four spatial and two temporal positions within the field is used to derive conditions for spatio-temporal coupling. An example is included which deals with a spatio-temporal coupling in a typical REMPB on reflection from a reflecting grating. Electromagnetic nature of such interaction is explored via considering dependence of the degree of polarization of the reflected REMPB on its source and on the structure of the grating.
1993-01-01
A contact interaction is proposed to exist between the voltage sensor of the transverse tubular membrane of skeletal muscle and the calcium release channel of the sarcoplasmic reticulum. This interaction is given a quantitative formulation inspired in the Monod, Wyman, and Changeux model of allosteric transitions in hemoglobin (Monod, J., J. Wyman, and J.-P. Changeux. 1965. Journal of Molecular Biology. 12:88- 118), and analogous to one proposed by Marks and Jones for voltage- dependent Ca channels (Marks, T. N., and S. W. Jones. 1992. Journal of General Physiology. 99:367-390). The allosteric protein is the calcium release channel, a homotetramer, with two accessible states, closed and open. The kinetics and equilibrium of this transition are modulated by voltage sensors (dihydropyridine receptors) pictured as four units per release channel, each undergoing independent voltage-driven transitions between two states (resting and activating). For each voltage sensor that moves to the activating state, the tendency of the channel to open increases by an equal (large) factor. The equilibrium and kinetic equations of the model are solved and shown to reproduce well a number of experimentally measured relationships including: charge movement (Q) vs. voltage, open probability of the release channel (Po) vs. voltage, the transfer function relationship Po vs. Q, and the kinetics of charge movement, release activation, and deactivation. The main consequence of the assumption of allosteric coupling is that primary effects on the release channel are transmitted backward to the voltage sensor and give secondary effects. Thus, the model reproduces well the effects of perchlorate, described in the two previous articles, under the assumption that the primary effect is to increase the intrinsic tendency of the release channel to open, with no direct effects on the voltage sensor. This modification of the open-closed equilibrium of the release channel causes a shift in the
Psychometric properties of the system for coding couples' interactions in therapy--alcohol.
Owens, Mandy D; McCrady, Barbara S; Borders, Adrienne Z; Brovko, Julie M; Pearson, Matthew R
2014-12-01
Few systems are available for coding in-session behaviors for couples in therapy. Alcohol Behavioral Couple Therapy (ABCT) is an empirically supported treatment, but little is known about its mechanisms of behavior change. In the current study, an adapted version of the Motivational Interviewing for Significant Others coding system was developed into the System for Coding Couples' Interactions in Therapy-Alcohol (SCCIT-A), which was used to code couples' interactions and behaviors during ABCT. Results showed good interrater reliability of the SCCIT-A and provided evidence that the SCCIT-A may be a promising measure for understanding couples in therapy. A 3-factor model of the SCCIT-A (Positive, Negative, and Change Talk/Counter-Change Talk) was examined using a confirmatory factor analysis, but model fit was poor. Because model fit was poor, ratios were computed for Positive/Negative ratings and for Change Talk/Counter-Change Talk codes based on previous research in the couples and Motivational Interviewing literature. Post hoc analyses examined correlations between specific SCCIT-A codes and baseline characteristics, and indicated some concurrent validity. Correlations were run between ratios and baseline characteristics; ratios may be an alternative to using the factors from the SCCIT-A. Reliability and validity analyses suggest that the SCCIT-A has the potential to be a useful measure for coding in-session behaviors of both partners in couples therapy and could be used to identify mechanisms of behavior change for ABCT. Additional research is needed to improve the reliability of some codes and to further develop the SCCIT-A and other measures of couples' interactions in therapy.
NASA Astrophysics Data System (ADS)
Cerroni, D.; Fancellu, L.; Manservisi, S.; Menghini, F.
2016-06-01
In this work we propose to study the behavior of a solid elastic object that interacts with a multiphase flow. Fluid structure interaction and multiphase problems are of great interest in engineering and science because of many potential applications. The study of this interaction by coupling a fluid structure interaction (FSI) solver with a multiphase problem could open a large range of possibilities in the investigation of realistic problems. We use a FSI solver based on a monolithic approach, while the two-phase interface advection and reconstruction is computed in the framework of a Volume of Fluid method which is one of the more popular algorithms for two-phase flow problems. The coupling between the FSI and VOF algorithm is efficiently handled with the use of MEDMEM libraries implemented in the computational platform Salome. The numerical results of a dam break problem over a deformable solid are reported in order to show the robustness and stability of this numerical approach.
Spin effects in the weak interaction
Freedman, S.J. Chicago Univ., IL . Dept. of Physics Chicago Univ., IL . Enrico Fermi Inst.)
1990-01-01
Modern experiments investigating the beta decay of the neutron and light nuclei are still providing important constraints on the theory of the weak interaction. Beta decay experiments are yielding more precise values for allowed and induced weak coupling constants and putting constraints on possible extensions to the standard electroweak model. Here we emphasize the implications of recent experiments to pin down the strengths of the weak vector and axial vector couplings of the nucleon.
Effect of charge delocalization on radical ion pair electronic coupling
NASA Astrophysics Data System (ADS)
Sinks, Louise E.; Weiss, Emily A.; Giaimo, Jovan M.; Wasielewski, Michael R.
2005-03-01
Photoinduced charge separation and recombination were studied in a series of covalent donor-acceptor triads consisting of aniline, 1-aminonaphthalene, or 9-aminoanthracene donors (D) attached to a 4-aminonaphthalene-1,8-dicarboximide chromophore (ANI), which in turn is attached to a naphthalene-1,4:5,8-bis(dicarboximide) acceptor (NI) to give D-ANI-NI. The relationship between the molecular structure of D + rad and the magnitude of the electronic coupling between the radicals within D + rad -ANI-NI - rad was probed by direct measurements of the spin-spin exchange interaction, 2J, using magnetic field effects on the yield of the neutral triplet state resulting from charge recombination and by density functional theory calculations.
Effective KN interaction based on chiral SU(3) dynamics
Hyodo, Tetsuo; Weise, Wolfram
2008-03-15
The effective KN interaction based on chiral SU(3) coupled-channel dynamics is derived and its extrapolation below the KN threshold is studied in detail. Starting from the coupled-channel scattering equations, we eliminate the channels other than KN and obtain an effective interaction in the single KN channel. An equivalent local potential in coordinate space is constructed such as to reproduce the full scattering amplitude of the chiral SU(3) coupled-channel framework. We discuss several realistic chiral SU(3)-based models in comparison to reach conclusions about the uncertainties involved. It turns out that, in the region relevant to the discussion of deeply bound K-nuclear few-body systems, the resulting energy-dependent, equivalent local potential is substantially less attractive than the one suggested in previous purely phenomenological treatments.
Evolution of a G protein-coupled receptor response by mutations in regulatory network interactions.
Di Roberto, Raphaël B; Chang, Belinda; Trusina, Ala; Peisajovich, Sergio G
2016-01-01
All cellular functions depend on the concerted action of multiple proteins organized in complex networks. To understand how selection acts on protein networks, we used the yeast mating receptor Ste2, a pheromone-activated G protein-coupled receptor, as a model system. In Saccharomyces cerevisiae, Ste2 is a hub in a network of interactions controlling both signal transduction and signal suppression. Through laboratory evolution, we obtained 21 mutant receptors sensitive to the pheromone of a related yeast species and investigated the molecular mechanisms behind this newfound sensitivity. While some mutants show enhanced binding affinity to the foreign pheromone, others only display weakened interactions with the network's negative regulators. Importantly, the latter changes have a limited impact on overall pathway regulation, despite their considerable effect on sensitivity. Our results demonstrate that a new receptor-ligand pair can evolve through network-altering mutations independently of receptor-ligand binding, and suggest a potential role for such mutations in disease. PMID:27487915
Evolution of a G protein-coupled receptor response by mutations in regulatory network interactions
Di Roberto, Raphaël B.; Chang, Belinda; Trusina, Ala; Peisajovich, Sergio G.
2016-01-01
All cellular functions depend on the concerted action of multiple proteins organized in complex networks. To understand how selection acts on protein networks, we used the yeast mating receptor Ste2, a pheromone-activated G protein-coupled receptor, as a model system. In Saccharomyces cerevisiae, Ste2 is a hub in a network of interactions controlling both signal transduction and signal suppression. Through laboratory evolution, we obtained 21 mutant receptors sensitive to the pheromone of a related yeast species and investigated the molecular mechanisms behind this newfound sensitivity. While some mutants show enhanced binding affinity to the foreign pheromone, others only display weakened interactions with the network's negative regulators. Importantly, the latter changes have a limited impact on overall pathway regulation, despite their considerable effect on sensitivity. Our results demonstrate that a new receptor–ligand pair can evolve through network-altering mutations independently of receptor–ligand binding, and suggest a potential role for such mutations in disease. PMID:27487915
Global constraints on vector-like WIMP effective interactions
Blennow, Mattias; Coloma, Pilar; Fernandez-Martinez, Enrique; Machado, Pedro A. N.; Zaldivar, Bryan
2016-04-07
In this work we combine information from relic abundance, direct detection, cosmic microwave background, positron fraction, gamma rays, and colliders to explore the existing constraints on couplings between Dark Matter and Standard Model constituents when no underlying model or correlation is assumed. For definiteness, we include independent vector-like effective interactions for each Standard Model fermion. Our results show that low Dark Matter masses below 20 GeV are disfavoured at the 3 σ level with respect to higher masses, due to the tension between the relic abundance requirement and upper constraints on the Dark Matter couplings. Lastly, large couplings are typically onlymore » allowed in combinations which avoid effective couplings to the nuclei used in direct detection experiments.« less
Deep-subwavelength magnetic-coupling-dominant interaction among magnetic localized surface plasmons
NASA Astrophysics Data System (ADS)
Gao, Zhen; Gao, Fei; Zhang, Youming; Zhang, Baile
2016-05-01
Magnetic coupling is generally much weaker than electric Coulomb interaction. This also applies to the well-known magnetic "meta-atoms," or split-ring resonators (SRRs) as originally proposed by Pendry et al. [IEEE Trans. Microwave Theory Tech. 47, 2075 (1999), 10.1109/22.798002], in which the associated electric dipole moments usually dictate their interaction. As a result, stereometamaterials, a stack of identical SRRs, were found with electric coupling so strong that the dispersion from merely magnetic coupling was overturned. Recently, other workers have proposed a new concept of magnetic localized surface plasmons, supported on metallic spiral structures (MSSs) at a deep-subwavelength scale. Here, we experimentally demonstrate that a stack of these magnetic "meta-atoms" can have dominant magnetic coupling in both of its two configurations. This allows magnetic-coupling-dominant energy transport along a one-dimensional stack of MSSs, as demonstrated with near-field transmission measurement. Our work not only applies this type of magnetic "meta-atom" into metamaterial construction, but also provides possibilities of magnetic metamaterial design in which the electric interaction no longer takes precedence.
Coupled effects of chemotaxis and growth on traveling bacterial waves.
Yan, Zhifeng; Bouwer, Edward J; Hilpert, Markus
2014-08-01
Traveling bacterial waves are capable of improving contaminant remediation in the subsurface. It is fairly well understood how bacterial chemotaxis and growth separately affect the formation and propagation of such waves. However, their interaction is not well understood. We therefore perform a modeling study to investigate the coupled effects of chemotaxis and growth on bacterial migration, and examine their effects on contaminant remediation. We study the waves by using different initial electron acceptor concentrations for different bacteria and substrate systems. Three types of traveling waves can occur: a chemotactic wave due to the biased movement of chemotactic bacteria resulting from metabolism-generated substrate concentration gradients; a growth/decay/motility wave due to a dynamic equilibrium between bacterial growth, decay and random motility; and an integrated wave due to the interaction between bacterial chemotaxis and growth. Chemotaxis hardly enhances the bacterial propagation if it is too weak to form a chemotactic wave or its wave speed is less than half of the growth/decay/motility wave speed. However, chemotaxis significantly accelerates bacterial propagation once its wave speed exceeds the growth/decay/motility wave speed. When convection occurs, it speeds up the growth/decay/motility wave but slows down or even eliminates the chemotactic wave due to the dispersion. Bacterial survival proves particularly important for bacterial propagation. Therefore we develop a conceptual model to estimate the speed of growth/decay/motility waves.
NASA Astrophysics Data System (ADS)
Leitner, Daniel; Bodner, Gernot; Raoof, Amir
2013-04-01
, but also improve the description of the rooting environment. Until now there have been no attempts to couple root architecture and pore network models. In our work we present a first attempt to join both types of models using the root architecture model of Leitner et al., (2010) and a pore network model presented by Raoof et al. (2010). The two main objectives of coupling both models are: (i) Representing the effect of root induced biopores on flow and transport processes: For this purpose a fixed root architecture created by the root model is superimposed as a secondary root induced pore network to the primary soil network, thus influencing the final pore topology in the network generation. (ii) Representing the influence of pre-existing pores on root branching: Using a given network of (rigid) pores, the root architecture model allocates its root axes into these preexisting pores as preferential growth paths with thereby shape the final root architecture. The main objective of our study is to reveal the potential of using a pore scale description of the plant growth medium for an improved representation of interaction processes at the interface of root and soil. References Raoof, A., Hassanizadeh, S.M. 2010. A New Method for Generating Pore-Network Models. Transp. Porous Med. 81, 391-407. Leitner, D, Klepsch, S., Bodner, G., Schnepf, S. 2010. A dynamic root system growth model based on L-Systems. Tropisms and coupling to nutrient uptake from soil. Plant Soil 332, 177-192.
Enhanced interaction between a mechanical oscillator and two coupled resonant electrical circuits
Dmitriev, A. V.; Mitrofanov, V. P.
2014-01-01
This paper reports result of calculation and experimental realization of an electromechanical system that consists of a high-Q mechanical oscillator parametrically coupled in the manner of a capacitive transducer with a radio frequency (RF) circuit, which is in turn inductively coupled with another RF circuit. The system operates in the resolved sideband regime when the mechanical oscillator's frequency is larger than the electrical circuits' bandwidths. Using two coupled RF circuits allowed one to enhance the interaction between them and the mechanical oscillator which is one of flexural vibrational modes of a free-edge circular silicon wafer. Such a coupled electromechanical system can be used as a high-sensitive capacitive vibration sensor. PMID:25173304
Re-visit local coupling correction in the interaction regions of RHIC
Luo, Y.; Fischer, W.; Liu, C.; Marusic, A.; Minty, M.; Ptitsyn, V.; Schoefer, V.; Tepikian, S.; Trbojevic, D.; Zimmer, C.
2011-11-01
In this article we will re-visit the local coupling correction in the interaction regions (IRs) of the Relativistic Heavy Ion Collider (RHIC). We will review the measurement data of triplet quadrupole rolls, the local coupling correction strengths in the RHIC control system, and the methods for the local coupling correction with local skew quadrupole correctors. Based on the in-turnnel measurement data of triplet roll errors in 2011, we will analytically calculate and simulate IR-bump method to find out the local skew correction strengths and compare them at store and at injection with the Blue and Yellow ring lattices in the 2011 polarized proton (p-p) and Au-Au runs. The vertical dispersion from the triplet roll errors, local and global coupling correction skew quadrupoles, and the vertical dipole correctors are calculated and discussed.
Final State Interactions Effects in Neutrino-Nucleus Interactions
Golan, Tomasz; Juszczak, Cezary; Sobczyk, Jan T.
2012-07-01
Final State Interactions effects are discussed in the context of Monte Carlo simulations of neutrino-nucleus interactions. A role of Formation Time is explained and several models describing this effect are compared. Various observables which are sensitive to FSI effects are reviewed including pion-nucleus interaction and hadron yields in backward hemisphere. NuWro Monte Carlo neutrino event generator is described and its ability to understand neutral current $\\pi^0$ production data in $\\sim 1$ GeV neutrino flux experiments is demonstrated.
Enhancement of Kondo effect through Rashba spin-orbit interactions
NASA Astrophysics Data System (ADS)
Sandler, Nancy; Zarea, Mehdi; Ulloa, Sergio
2011-03-01
The role of Rashba spin-orbit (RSO) interactions on the Kondo regime has been a topic of debate since resistivity measurements on Pt doped Cu:Mn compounds were interpreted as evidence for suppression of the Kondo effect by SO scattering. Subsequent theoretical and experimental activity has yielded conflicting results. Thus, the question: what is the role of SO interactions in the Kondo regime? remains open. To provide a definite answer we obtain an exact solution of an Anderson magnetic impurity model in a two-dimensional metallic host with RSO interactions. We show that the Hamiltonian reduces to an effective two-band Anderson model coupled to a S=1/2 impurity. An appropriate Schrieffer-Wolff transformation produces an effective 2-channel Kondo model plus a Dzyaloshiinski-Moriya (DM) interaction term. The exact solution reveals that the impurity couples to the bath with ferro- and antiferromagnetic couplings. DM interactions, that vanish at half-filling and at the Hubbard U-infinity limits, introduce an exponential increase in the value of the Kondo temperature. Supported by NSF-PIRE and MWN/CIAM.
NASA Astrophysics Data System (ADS)
Fuller-Rowell, T. J.
2011-12-01
Coupled thermosphere ionosphere physics-based models have about a 25 year heritage. This paper reviews the physical processes pertaining to the interaction between the neutral and plasma domains, and what we have learnt from the coupling physics embedded in the models. The interactions range from the chemical to the dynamic, from the linear to the non-linear, and from the intuitive to the non-intuitive. For example, coupled thermosphere-ionosphere models have been able to unravel some of the complexities of the storm-time response, in particular the observed seasonal/local-time characteristics of the ionospheric negative phase and its connection to the transport of thermospheric major species. Another example is the unexpected asymmetry in the neutral wind response to magnetospheric forcing, which is a good example of a non-linear response. Both these cases illustrate how, physical modeling, firstly, can be used as a tool to simulate the phenomena, and secondly, can be used to elucidate the underlying physical processes at work. This second step, is the most difficult and time-consuming, and is often neglected. Still many outstanding issues remain, which will likely be address by coupling to the neighboring domains. For instance, the challenge of the semi-annual variation in several neutral and plasma parameters has yet to be modeled successfully. The hope is that coupling with the lower atmosphere will shed light on the physical processes. Another example is the huge increases in plasma density at mid-latitudes, which likely requires careful coupling of thermosphere-ionosphere with both inner and outer magnetosphere codes. Both these directions, coupling with the lower atmosphere and with the magnetosphere, are active and fruitful lines of research that will provide the momentum for future advances in understanding of the coupled geospace physical system.
Brogi, Bharat Bhushan Ahluwalia, P. K.; Chand, Shyam
2015-06-24
Theoretical study of the Coulomb blockade effect on transport properties (Transmission Probability and I-V characteristics) for varied configuration of coupled quantum dot system has been studied by using Non Equilibrium Green Function(NEGF) formalism and Equation of Motion(EOM) method in the presence of magnetic flux. The self consistent approach and intra-dot Coulomb interaction is being taken into account. As the key parameters of the coupled quantum dot system such as dot-lead coupling, inter-dot tunneling and magnetic flux threading through the system can be tuned, the effect of asymmetry parameter and magnetic flux on this tuning is being explored in Coulomb blockade regime. The presence of the Coulomb blockade due to on-dot Coulomb interaction decreases the width of transmission peak at energy level ε + U and by adjusting the magnetic flux the swapping effect in the Fano peaks in asymmetric and symmetric parallel configuration sustains despite strong Coulomb blockade effect.
Interaction-induced hopping phase in driven-dissipative coupled photonic microcavities.
Rodriguez, S R K; Amo, A; Sagnes, I; Le Gratiet, L; Galopin, E; Lemaître, A; Bloch, J
2016-01-01
The Bose-Hubbard model (BHM) describes bosons hopping across sites and interacting on-site. Inspired by the success of BHM simulators with atoms in optical lattices, proposals for implementing the BHM with photons in coupled nonlinear cavities have recently emerged. Two coupled semiconductor microcavities constitute a model system where the hopping, interaction and decay of exciton polaritons-mixed light-matter quasiparticles-can be engineered in combination with site-selective coherent driving to implement the driven-dissipative two-site optical BHM. Here we explore the interplay of interference and nonlinearity in this system, in a regime where three distinct density profiles can be observed under identical driving conditions. We demonstrate how the phase acquired by polaritons hopping between cavities can be controlled through polariton-polariton interactions. Our results open new perspectives for synthesizing density-dependent gauge fields using polaritons in two-dimensional multicavity systems. PMID:27307038
Interaction-induced hopping phase in driven-dissipative coupled photonic microcavities
Rodriguez, S. R. K.; Amo, A.; Sagnes, I.; Le Gratiet, L.; Galopin, E.; Lemaître, A.; Bloch, J.
2016-01-01
The Bose-Hubbard model (BHM) describes bosons hopping across sites and interacting on-site. Inspired by the success of BHM simulators with atoms in optical lattices, proposals for implementing the BHM with photons in coupled nonlinear cavities have recently emerged. Two coupled semiconductor microcavities constitute a model system where the hopping, interaction and decay of exciton polaritons—mixed light-matter quasiparticles—can be engineered in combination with site-selective coherent driving to implement the driven-dissipative two-site optical BHM. Here we explore the interplay of interference and nonlinearity in this system, in a regime where three distinct density profiles can be observed under identical driving conditions. We demonstrate how the phase acquired by polaritons hopping between cavities can be controlled through polariton-polariton interactions. Our results open new perspectives for synthesizing density-dependent gauge fields using polaritons in two-dimensional multicavity systems. PMID:27307038
Interaction-induced hopping phase in driven-dissipative coupled photonic microcavities.
Rodriguez, S R K; Amo, A; Sagnes, I; Le Gratiet, L; Galopin, E; Lemaître, A; Bloch, J
2016-06-16
The Bose-Hubbard model (BHM) describes bosons hopping across sites and interacting on-site. Inspired by the success of BHM simulators with atoms in optical lattices, proposals for implementing the BHM with photons in coupled nonlinear cavities have recently emerged. Two coupled semiconductor microcavities constitute a model system where the hopping, interaction and decay of exciton polaritons-mixed light-matter quasiparticles-can be engineered in combination with site-selective coherent driving to implement the driven-dissipative two-site optical BHM. Here we explore the interplay of interference and nonlinearity in this system, in a regime where three distinct density profiles can be observed under identical driving conditions. We demonstrate how the phase acquired by polaritons hopping between cavities can be controlled through polariton-polariton interactions. Our results open new perspectives for synthesizing density-dependent gauge fields using polaritons in two-dimensional multicavity systems.
NASA Astrophysics Data System (ADS)
De Lucia, Marco; Kühn, Michael
2013-04-01
manipulations and visualization in a powerful high level language, and benefiting from an enormous amount of third-party open source R extensions. The possibility to rapidly prototype complex algorithms involving geochemical modelling is in our opinion a huge advantage. A demonstration is given by the successful evaluation of a strategy to reduce the CPU-time needed to perform reactive transport simulations in a sequential coupling scheme. The idea is the "reduction" of the number of actual chemical simulations to perform at every time step, by searching for "duplicates" of each chemical simulations in the grid: such comparison involves typically a huge number of elements (one chemical simulation for grid element for time step) and a quite large number of variables (concentrations and mineral abundances). However, through the straightforward implementation of the prototype algorithm through the R/PHREEQC interface, we found out that the scan is extremely cost-effective in terms of CPU-time and typically allows a relevant speedup for simulations starting from a homogeneous or zone-homogeneous state. This speedup can even greatily exceed that of parallelization in some favorable but not unfrequent case. This feature should therefore be implemented in reactive transport simulators. References [1] Parkhurst D, Appelo C (1999) Users guide to PHREEQC (version 2). Tech. rep, U.S. Geological Survey. [2] Beyer C, Li D, De Lucia M, Kühn M, Bauer S (2012): Modelling CO2-induced fluid-rock interactions in the Altensalzwedel gas reservoir. Part II: coupled reactive transport simulation. Environ. Earth Sci., 67, 2, 573-588. [3] R Core Team (2012) R: A language and environment for statistical computing. R Foundation for Statistical Computing, Vienna, Austria. ISBN 3-900051-07-0, URL http://www.R-project.org/. [4] Kühn M, Münch U (2012) CLEAN: CO2 Large-Scale Enhanced Gas Recovery. GEOTECHNOLOGIEN Science Report No. 19. Series: Advanced. Technologies in Earth Sciences, 199 p, ISBN 978-3-642-31676-0.
NASA Technical Reports Server (NTRS)
Edwards, John W.
1996-01-01
A viscous-inviscid interactive coupling method is used for the computation of unsteady transonic flows involving separation and reattachment. A lag-entrainment integral boundary layer method is used with the transonic small disturbance potential equation in the CAP-TSDV (Computational Aeroelasticity Program - Transonic Small Disturbance) code. Efficient and robust computations of steady and unsteady separated flows, including steady separation bubbles and self-excited shock-induced oscillations are presented. The buffet onset boundary for the NACA 0012 airfoil is accurately predicted and shown computationally to be a Hopf bifurcation. Shock-induced oscillations are also presented for the 18 percent circular arc airfoil. The oscillation onset boundaries and frequencies are accurately predicted, as is the experimentally observed hysteresis of the oscillations with Mach number. This latter stability boundary is identified as a jump phenomenon. Transonic wing flutter boundaries are also shown for a thin swept wing and for a typical business jet wing, illustrating viscous effects on flutter and the effect of separation onset on the wing response at flutter. Calculations for both wings show limit cycle oscillations at transonic speeds in the vicinity of minimum flutter speed indices.
Effect of random charge fluctuation on strongly coupled dusty Plasma
Issaad, M.; Rouiguia, L.; Djebli, M.
2008-09-07
Modeling the interaction between particles is an open issue in dusty plasma. We dealt with strongly coupled dust particles in two dimensional confined system. For small number of clusters, we investigate the effect of random charge fluctuation on background configuration. The study is conducted for a short rang as well as a long rang potential interaction. Numerical simulation is performed using Monte-Carlo simulation in the presence of parabolic confinement and at low temperature. We have studied the background configurations for a dust particles with constant charge and in the presence of random charge fluctuation due to the discrete nature of charge carriers. The latter is studied for a positively charged dust when the dominant charging process is due to photo-emission from the dust surface. It is found, for small classical cluster consisting of small number of particles, short rang potential gives the same result as long rang one. It is also found that the random charge fluctuation affect the background configurations.
Scale Interactions by physics in a Simplified Multiscale Coupled Atmosphere-Ocean nonlinear model
NASA Astrophysics Data System (ADS)
Ramirez, E.; Dias, P. L. D. S.; Raupp, C. F. M.; Ramirez Gutierrez, E. M. A.
2015-12-01
A simplified multiscale model of the interactions between the atmosphere and ocean is developed. Two coupled nonlinear equatorial β-plane shallow water equations are used. The nonlinearities are of two types: advective and atmosphere-ocean coupling related. To mimic the main differences between the fast-atmosphere and the slow-ocean, multi-space and multi-time scalings are adopted. Three possible regimes have been discussed: intradiurnal/synoptic/intraseasonal (ISIn), synoptic/intraseasonal/interannual-El Niño (SInEN) and intraseasonal/El Niño/decadal (InEND) regimes. Special attention is given to the SInEN regime, where simplified physical parameterizations for the atmosphere-ocean coupling are developed. In this regime, the synoptic scale is the fastest atmospheric scale, the intraseasonal is the intermediate atmosphere-ocean coupling scale and the El Niño refers to the slowest inter-annual ocean scale. Analytical solutions of the SInEN equations reveal that the slow wave amplitude evolution depends on both types of nonlinearities. Nonlinear interactions of synoptic scale atmospheric waves force intraseasonal variability not only in the atmosphere but also in the ocean through wind stress. Intraseasonal ocean temperature perturbations coupled with the atmosphere through evaporation force higher order atmospheric variability and the wave-convection coupling provides another source of higher order atmospheric variability. In the ocean, nonlinear interactions of intraseasonal ocean perturbations force interannual oceanic variability. The slowest inter-annual variability in the SInEN regime is associated with either nonlinear wind stress and advective nonlinearity.
The consistent Riccati expansion and new interaction solution for a Boussinesq-type coupled system
NASA Astrophysics Data System (ADS)
Ruan, Shao-Qing; Yu, Wei-Feng; Yu, Jun; Yu, Guo-Xiang
2015-06-01
Starting from the Davey-Stewartson equation, a Boussinesq-type coupled equation system is obtained by using a variable separation approach. For the Boussinesq-type coupled equation system, its consistent Riccati expansion (CRE) solvability is studied with the help of a Riccati equation. It is significant that the soliton-cnoidal wave interaction solution, expressed explicitly by Jacobi elliptic functions and the third type of incomplete elliptic integral, of the system is also given. Project supported by the National Natural Science Foundation of China (Grant No. 11275129).
Experimental determination of the effective strong coupling constant
Alexandre Deur; Volker Burkert; Jian-Ping Chen; Wolfgang Korsch
2007-07-01
We extract an effective strong coupling constant from low Q{sup 2} data on the Bjorken sum. Using sum rules, we establish its Q{sup 2}-behavior over the complete Q{sup 2}-range. The result is compared to effective coupling constants extracted from different processes and to calculations based on Schwinger-Dyson equations, hadron spectroscopy or lattice QCD. Although the connection between the experimentally extracted effective coupling constant and the calculations is not clear, the results agree surprisingly well.
Cost-Effectiveness of Interactive Courseware.
ERIC Educational Resources Information Center
Fletcher, J. D.
What is known about the cost effectiveness of interactive courseware (ICW) is reviewed, and issues that remain are summarized. Effect size is used for reporting the effectiveness of ICW programs. Two ICW media are considered: computer-based instruction and interactive videodisc instruction. Effect sizes for computer-based instruction have been…
NASA Astrophysics Data System (ADS)
Chen, X.; Johnson, T. C.; Hammond, G. E.; Zachara, J. M.
2014-12-01
The hydrological and biogeochemical processes at the groundwater and river water interface are largely controlled by the exchange dynamics between the two water bodies. Accurate characterization of the heterogeneous permeability field at such interface is critical for modeling the bulk flow as well as the biogeochemical processes that are coupled with the flow. Taking advantage of the distinct conductivities in groundwater and rive water, time lapse electrical resistivity tomography (ERT) can provide rich spatial and temporal data for characterizing the permeability field, by imaging the change in subsurface electric conductivity driven by river water intrusion and retreat. We installed a large-scale (300 m by 300 m) 3-dimensional ERT array to monitor river water intrusion and retreat through time at a major river corridor, and the 4-dimensional electrical geophysical data is assimilated to invert for the underlying permeability field using ensemble-based algorithms (e.g., ensemble Kalman filter and ensemble smoother). We developed a new high-performance hydrogeophysical code by coupling an ERT imaging code E4D (Johnson et al., 2010) with a site-scale flow and transport code, PFLOTRAN (Hammond et al., 2012). The coupled code provides the key modeling capability of multi-physics processes, parallel efficiency, and multi-realization simulation capability for hydrogeophysical inversion. We assimilated both well-based point measurements of water table and specific conductance and spatially continuous ERT images in a sequential Bayesian way. Our study demonstrates the effectiveness of joint hydrogeophysical inversion for large-scale characterization of subsurface properties in the groundwater and river water interaction zone. Our investigation of spatial versus temporal data assimilation strategies have inspired systematic data worth analyses to identify the most valuable data sets for hydrogeophysical inversion. The high performance computing is performed on the Hopper
Holguín-Gallego, Fernando José; Chávez-Calvillo, Rodrigo; García-Revilla, Marco; Francisco, Evelio; Pendás, Ángel Martín; Rocha-Rinza, Tomás
2016-07-15
The electronic energy partition established by the Interacting Quantum Atoms (IQA) approach is an important method of wavefunction analyses which has yielded valuable insights about different phenomena in physical chemistry. Most of the IQA applications have relied upon approximations, which do not include either dynamical correlation (DC) such as Hartree-Fock (HF) or external DC like CASSCF theory. Recently, DC was included in the IQA method by means of HF/Coupled-Cluster (CC) transition densities (Chávez-Calvillo et al., Comput. Theory Chem. 2015, 1053, 90). Despite the potential utility of this approach, it has a few drawbacks, for example, it is not consistent with the calculation of CC properties different from the total electronic energy. To improve this situation, we have implemented the IQA energy partition based on CC Lagrangian one- and two-electron orbital density matrices. The development presented in this article is tested and illustrated with the H2 , LiH, H2 O, H2 S, N2 , and CO molecules for which the IQA results obtained under the consideration of (i) the CC Lagrangian, (ii) HF/CC transition densities, and (iii) HF are critically analyzed and compared. Additionally, the effect of the DC in the different components of the electronic energy in the formation of the T-shaped (H2 )2 van der Waals cluster and the bimolecular nucleophilic substitution between F(-) and CH3 F is examined. We anticipate that the approach put forward in this article will provide new understandings on subjects in physical chemistry wherein DC plays a crucial role like molecular interactions along with chemical bonding and reactivity. © 2016 Wiley Periodicals, Inc. PMID:27237084
Holguín-Gallego, Fernando José; Chávez-Calvillo, Rodrigo; García-Revilla, Marco; Francisco, Evelio; Pendás, Ángel Martín; Rocha-Rinza, Tomás
2016-07-15
The electronic energy partition established by the Interacting Quantum Atoms (IQA) approach is an important method of wavefunction analyses which has yielded valuable insights about different phenomena in physical chemistry. Most of the IQA applications have relied upon approximations, which do not include either dynamical correlation (DC) such as Hartree-Fock (HF) or external DC like CASSCF theory. Recently, DC was included in the IQA method by means of HF/Coupled-Cluster (CC) transition densities (Chávez-Calvillo et al., Comput. Theory Chem. 2015, 1053, 90). Despite the potential utility of this approach, it has a few drawbacks, for example, it is not consistent with the calculation of CC properties different from the total electronic energy. To improve this situation, we have implemented the IQA energy partition based on CC Lagrangian one- and two-electron orbital density matrices. The development presented in this article is tested and illustrated with the H2 , LiH, H2 O, H2 S, N2 , and CO molecules for which the IQA results obtained under the consideration of (i) the CC Lagrangian, (ii) HF/CC transition densities, and (iii) HF are critically analyzed and compared. Additionally, the effect of the DC in the different components of the electronic energy in the formation of the T-shaped (H2 )2 van der Waals cluster and the bimolecular nucleophilic substitution between F(-) and CH3 F is examined. We anticipate that the approach put forward in this article will provide new understandings on subjects in physical chemistry wherein DC plays a crucial role like molecular interactions along with chemical bonding and reactivity. © 2016 Wiley Periodicals, Inc.
NASA Astrophysics Data System (ADS)
Tu, Zhe-Yan; Wang, Wen-Liang; Li, Ren-Zhong; Xia, Cai-Juan; Li, Lian-Bi
2016-07-01
The CCSD(T) approach based on two-component relativistic effective core potential with spin-orbit interaction just included in coupled cluster iteration is adopted to study the spectroscopic constants of ground states of Kr2, Xe2 and Rn2 dimers. The spectroscopic constants have significant basis set dependence. Extrapolation to the complete basis set limit provides the most accurate values. The spin-orbit interaction hardly affects the spectroscopic constants of Kr2 and Xe2. However, the equilibrium bond length is shortened about 0.013 Å and the dissociation energy is augmented about 18 cm-1 by the spin-orbit interaction for Rn2 in the complete basis set limit.
Synchronization and plateau splitting of coupled oscillators with long-range power-law interactions.
Kuo, Huan-Yu; Wu, Kuo-An
2015-12-01
We investigate synchronization and plateau splitting of coupled oscillators on a one-dimensional lattice with long-range interactions that decay over distance as a power law. We show that in the thermodynamic limit the dynamics of systems of coupled oscillators with power-law exponent α≤1 is identical to that of the all-to-all coupling case. For α>1, oscillatory behavior of the phase coherence appears as a result of single plateau splitting into multiple plateaus. A coarse-graining method is used to investigate the onset of plateau splitting. We analyze a simple oscillatory state formed by two plateaus in detail and propose a systematic approach to predict the onset of plateau splitting. The prediction of breaking points of plateau splitting is in quantitatively good agreement with numerical simulations. PMID:26764785
Floyd, Frank J.; Daugherty, Michelle Klotz; Fitzgerald, Hiram H.; Cranford, James A.; Zucker, Robert A.
2008-01-01
The authors examined problem-solving marital interactions of alcoholic and nonalcoholic couples (N = 132). Four alcoholic groups (husband alcoholic with antisocial personality disorder or not, paired with alcoholic or nonalcoholic wives) were compared with each other and with a both-spouses-nonalcoholic group. Consistent with the alcoholic subtypes hypothesis, couples with an antisocial alcoholic husband had higher levels of hostile behavior regardless of wives’ alcoholism status. In contrast, rates of positive behaviors and the ratio of positive to negative behaviors were greatest among couples in which either both or neither of the spouses had alcoholic diagnoses and were lowest among alcoholic husbands with nonalcoholic wives. Discussion focuses on possible mechanisms linking antisocial alcoholism and discrepant alcoholic diagnoses to poorer marital outcomes. PMID:16492103
Synchronization and plateau splitting of coupled oscillators with long-range power-law interactions.
Kuo, Huan-Yu; Wu, Kuo-An
2015-12-01
We investigate synchronization and plateau splitting of coupled oscillators on a one-dimensional lattice with long-range interactions that decay over distance as a power law. We show that in the thermodynamic limit the dynamics of systems of coupled oscillators with power-law exponent α≤1 is identical to that of the all-to-all coupling case. For α>1, oscillatory behavior of the phase coherence appears as a result of single plateau splitting into multiple plateaus. A coarse-graining method is used to investigate the onset of plateau splitting. We analyze a simple oscillatory state formed by two plateaus in detail and propose a systematic approach to predict the onset of plateau splitting. The prediction of breaking points of plateau splitting is in quantitatively good agreement with numerical simulations.
Coupled hydrodynamic model for laser-plasma interaction and hot electron generation
NASA Astrophysics Data System (ADS)
Colaïtis, A.; Duchateau, G.; Ribeyre, X.; Maheut, Y.; Boutoux, G.; Antonelli, L.; Nicolaï, Ph.; Batani, D.; Tikhonchuk, V.
2015-10-01
We present a formulation of the model of laser-plasma interaction (LPI) at hydrodynamical scales that couples the plasma dynamics with linear and nonlinear LPI processes, including the creation and propagation of high-energy electrons excited by parametric instabilities and collective effects. This formulation accounts for laser beam refraction and diffraction, energy absorption due to collisional and resonant processes, and hot electron generation due to the stimulated Raman scattering, two-plasmon decay, and resonant absorption processes. Hot electron (HE) transport and absorption are described within the multigroup angular scattering approximation, adapted for transversally Gaussian electron beams. This multiscale inline LPI-HE model is used to interpret several shock ignition experiments, highlighting the importance of target preheating by HEs and the shortcomings of standard geometrical optics when modeling the propagation and absorption of intense laser pulses. It is found that HEs from parametric instabilities significantly increase the shock pressure and velocity in the target, while decreasing its strength and the overall ablation pressure.
Coupled hydrodynamic model for laser-plasma interaction and hot electron generation.
Colaïtis, A; Duchateau, G; Ribeyre, X; Maheut, Y; Boutoux, G; Antonelli, L; Nicolaï, Ph; Batani, D; Tikhonchuk, V
2015-10-01
We present a formulation of the model of laser-plasma interaction (LPI) at hydrodynamical scales that couples the plasma dynamics with linear and nonlinear LPI processes, including the creation and propagation of high-energy electrons excited by parametric instabilities and collective effects. This formulation accounts for laser beam refraction and diffraction, energy absorption due to collisional and resonant processes, and hot electron generation due to the stimulated Raman scattering, two-plasmon decay, and resonant absorption processes. Hot electron (HE) transport and absorption are described within the multigroup angular scattering approximation, adapted for transversally Gaussian electron beams. This multiscale inline LPI-HE model is used to interpret several shock ignition experiments, highlighting the importance of target preheating by HEs and the shortcomings of standard geometrical optics when modeling the propagation and absorption of intense laser pulses. It is found that HEs from parametric instabilities significantly increase the shock pressure and velocity in the target, while decreasing its strength and the overall ablation pressure.
Coupled hydrodynamic model for laser-plasma interaction and hot electron generation.
Colaïtis, A; Duchateau, G; Ribeyre, X; Maheut, Y; Boutoux, G; Antonelli, L; Nicolaï, Ph; Batani, D; Tikhonchuk, V
2015-10-01
We present a formulation of the model of laser-plasma interaction (LPI) at hydrodynamical scales that couples the plasma dynamics with linear and nonlinear LPI processes, including the creation and propagation of high-energy electrons excited by parametric instabilities and collective effects. This formulation accounts for laser beam refraction and diffraction, energy absorption due to collisional and resonant processes, and hot electron generation due to the stimulated Raman scattering, two-plasmon decay, and resonant absorption processes. Hot electron (HE) transport and absorption are described within the multigroup angular scattering approximation, adapted for transversally Gaussian electron beams. This multiscale inline LPI-HE model is used to interpret several shock ignition experiments, highlighting the importance of target preheating by HEs and the shortcomings of standard geometrical optics when modeling the propagation and absorption of intense laser pulses. It is found that HEs from parametric instabilities significantly increase the shock pressure and velocity in the target, while decreasing its strength and the overall ablation pressure. PMID:26565161
Evidence for acoustic-wave coupling in the magnetostatic-wave-optical interaction
NASA Astrophysics Data System (ADS)
Bilaniuk, Nykolai; Stancil, Daniel D.
1990-05-01
We have observed the collinear interaction between optical guided modes and magnetostatic forward-volume waves in a film of yttrium iron garnet (YIG) with microwave frequencies between 500 MHz and 12 GHz. The interaction occurred in one of two 5.3-μm films of YIG on either side of a 470-μm substrate of gadolinium gallium garnet (GGG). The intensity of the diffracted optical beam was measured as the microwave frequency was swept about the center frequency, with magnetic bias field held constant. We refer to this measurement as the interaction passband. Below 1 GHz, we observed absorption notches in the interaction passband with a regular period of 3.7 MHz. These are interpreted as evidence of coupling to transverse acoustic resonances through the sample thickness. This spacing agrees with a simple calculation based on transverse acoustic velocities in YIG of 3843 m/s and GGG of 3568 m/s.
Final Report. Coupled simulations of Antarctic Ice-sheet/ocean interactions using POP and CISM
Asay-Davis, Xylar Storm
2015-12-30
The project performed under this award, referred to from here on as CLARION (CoupLed simulations of Antarctic Ice-sheet/Ocean iNteractions), included important advances in two models of ice sheet and ocean interactions. Despite its short duration (one year), the project made significant progress on its three major foci. First, together with collaborator Daniel Martin at Lawrence Berkeley National Laboratory (LBNL), I developed the POPSICLES coupled ice sheet-ocean model to the point where it could perform a number of pan-Antarctic simulations under various forcing conditions. The results were presented at a number of major conferences and workshops worldwide, and are currently being incorporated into two manuscripts in preparation.
Synchronization in interacting populations of heterogeneous oscillators with time-varying coupling.
So, Paul; Cotton, Bernard C; Barreto, Ernest
2008-09-01
In many networks of interest (including technological, biological, and social networks), the connectivity between the interacting elements is not static, but changes in time. Furthermore, the elements themselves are often not identical, but rather display a variety of behaviors, and may come in different classes. Here, we investigate the dynamics of such systems. Specifically, we study a network of two large interacting heterogeneous populations of limit-cycle oscillators whose connectivity switches between two fixed arrangements at a particular frequency. We show that for sufficiently high switching frequency, this system behaves as if the connectivity were static and equal to the time average of the switching connectivity. We also examine the mechanisms by which this fast-switching limit is approached in several nonintuitive cases. The results illuminate novel mechanisms by which synchronization can arise or be thwarted in large populations of coupled oscillators with nonstatic coupling.
Transport properties of coupled one-dimensional interacting electron systems with impurities
NASA Astrophysics Data System (ADS)
Kimura, Takashi; Kuroki, Kazuhiko; Aoki, Hideo
1995-05-01
We consider two one-dimensional interacting electron systems that are coupled via interchain tunneling to calculate transport properties in the presence of impurities or a single barrier by using the bosonization formalisms for the non-Luttinger-liquid phases on the phase diagram obtained by Fabrizio [Phys. Rev. B 48, 15 838 (1993)]. We find for the weak- and strong-interaction phases, where the superconducting correlation dominates in the ground state, that the interchain transfer enhances the conductivity and the Anderson localization is suppressed. This shows that multichain systems can have unique transport properties.
Wang, Shu-Wen; Repetti, Rena L
2016-06-01
We examined sex differences in explicitly supportive behavior exchanges between husbands and wives using naturalistic video-recordings of everyday couple interactions inside the home. Thirty dual-earner, middle class, heterosexual couples with school-age children were recorded in their homes over 4 days. Specific instances of face-to-face explicit couple support in the video-recordings were identified, and the support role assumed by each partner (recipient vs. provider), the method of support initiation (solicitations vs. offers), and the type of support (instrumental vs. emotional) in each interaction were coded. Paired samples t tests examined sex differences in husbands' and wives' supportive behavior, and bivariate correlations tested the associations among spouses' support initiation behaviors. Findings counter prior research that has largely found a "support gap" favoring husbands as support recipients. Instead, results indicate that wives received significantly more support of an instrumental nature from husbands (than husbands did from wives), a finding driven by wives' active support-soliciting behavior. Among husbands, a tendency to be the solicitor of support was positively correlated with a tendency to offer support. Within couples, rates of offers of support by 1 spouse were correlated with offers by the partner. Naturalistic observations highlight processes that may not be detected by self-reports or laboratory data, in an ecologically valid context in which social behavior reflects the natural rhythms and pulls of everyday life. (PsycINFO Database Record PMID:27010600
Knobloch-Fedders, Lynne M; Critchfield, Kenneth L; Boisson, Tania; Woods, Naomi; Bitman, Rachel; Durbin, C Emily
2014-04-01
This study investigated the associations among depression, relationship quality, and demand/withdraw and demand/submit behavior in couples' conflict interactions. Two 10-min conflict interactions were coded for each couple (N = 97) using Structural Analysis of Social Behavior (SASB; Benjamin, 1979a, 1987, 2000a). Depression was assessed categorically (via the presence of depressive disorders) and dimensionally (via symptom reports). Results revealed that relationship quality was negatively associated with demanding behavior, as well as receiving submissive or withdrawing behavior from one's partner. Relationship quality was positively associated with withdrawal. Demanding behavior was positively associated with women's depression symptoms but negatively associated with men's depression symptoms. Sequential analysis revealed couples' behavior was highly stable across time. Initiation of demand/withdraw and demand/submit sequences were negatively associated with partners' relationship adjustment. Female demand/male withdraw was positively associated with men's depression diagnosis. Results underscore the importance of sequential analysis when investigating associations among depression, relationship quality, and couples' interpersonal behavior. PMID:24749515
Frisch, E.; Johnson, C.G.
1962-05-15
A detachable coupling arrangement is described which provides for varying the length of the handle of a tool used in relatively narrow channels. The arrangement consists of mating the key and keyhole formations in the cooperating handle sections. (AEC)
Coriolis cross-coupling effects: disorienting and nauseogenic or not?
Guedry, F E; Benson, A J
1978-01-01
Nausea and disorientation are sometimes produced by head movements during turning maneuvers in aircraft. These responses are usually attributed to Coriolis cross-coupling stimulation of the vestibular system, although it has been indicated recently that many turning maneuvers of aircraft have insufficient angular velocity to generate such effects. The purpose of the present study was to further distinguish conditions in which Coriolis cross-coupling effects are disorienting and nauseogenic from conditions in which they are neither.
Filadi, Riccardo; Greotti, Elisa; Turacchio, Gabriele; Luini, Alberto; Pozzan, Tullio; Pizzo, Paola
2016-06-01
Communication between organelles plays key roles in cell biology. In particular, physical and functional coupling of the endoplasmic reticulum (ER) and mitochondria is crucial for regulation of various physiological and pathophysiological processes. Here, we demonstrate that Presenilin 2 (PS2), mutations in which underlie familial Alzheimer's disease (FAD), promotes ER-mitochondria coupling only in the presence of mitofusin 2 (Mfn2). PS2 is not necessary for the antagonistic effect of Mfn2 on organelle coupling, although its abundance can tune it. The two proteins physically interact, whereas their homologues Mfn1 and PS1 are dispensable for this interplay. Moreover, PS2 mutants associated with FAD are more effective than the wild-type form in modulating ER-mitochondria tethering because their binding to Mfn2 in mitochondria-associated membranes is favored. We propose a revised model for ER-mitochondria interaction to account for these findings and discuss possible implications for FAD pathogenesis. PMID:27239030
NASA Astrophysics Data System (ADS)
Joshi, C.; Mohanty, B. P.
2006-12-01
Subsurface water exists primarily as groundwater and also in small quantity as soil water in the unsaturated zone. This soil water plays a vital role in the hydrologic cycle by supporting plant growth, regulating the amount of water lost to evapo-transpiration and affecting the surface water groundwater interaction to a certain extent. As such, the interaction between surface water and groundwater is complex and little understood. This study aims at investigating the surface water groundwater interaction in the Arkansas-Red river basin, using a coupled modeling platform. For this purpose, an ecohydrological model (SWAP) has been coupled with the groundwater model (MODFLOW). Inputs to this coupled model are collected from NEXRAD precipitation data at a resolution of ~4 km, meteorological forcings from Oklahoma mesonet and NCDC sites, STATSGO soil property data, LAI (Leaf Area Index) data from MODIS at a resolution of ~1 km, and DEM (Digital Elevation Model). For numerical modeling, a spatial resolution of ~1 km and a temporal resolution of one day is used. The modeled base flow and total groundwater storage change would be tested using ground water table observation data. The modeled ground water storage is further improved using GRACE (Gravity Recovery and Climate Experiment) satellite data at a resolution of ~400 km, with the help of appropriate data assimilation technique.
Vidmar, Janja; Martinčič, Anže; Milačič, Radmila; Ščančar, Janez
2015-06-01
Cisplatin is still widely used for treatment of numerous types of tumours. Different speciation methods have been applied to study behaviour of the intact drug and its individual biotransformation species in various clinical samples. These methods are mainly based on electrophoresis, size exclusion (SEC) or ion chromatography (IC) techniques coupled to inductively coupled plasma mass spectrometry (ICP-MS). Hydrophilic interaction liquid chromatography (HILIC), which is a common technique for separation of polar substances, was rarely applied for separation of cisplatin and its hydrolysed metabolites. There is also a lack of information available on the occurrence of cisplatin and its hydrolysed complexes in the environmental waters. In the present study the concentrations of Pt were determined in hospital wastewaters by ICP-MS. A procedure for separation of cisplatin and its aqueous hydrolysed complexes by the use of HILIC column was optimized. Quantification of separated Pt species was performed by isotope dilution (ID)-ICP-MS procedure. Low limits of detection (LODs) and quantification (LOQs) were obtained for cisplatin and its hydrolysed complexes ranging from 0.0273 to 0.1726 ng Pt/mL and from 0.0909 to 0.5753 ng Pt/mL, respectively. Good repeatability of the procedure with relative standard deviation (RSD) lower than ±2.3% was obtained. The column recoveries, which ranged from 95 to 101%, indicated that the procedure developed enabled quantitative speciation analysis of aqueous cisplatin complexes. The ZIC-HILIC-ID-ICP-MS procedure was successfully applied in speciation of cisplatin in spiked hospital wastewater samples.
A Coupled Fluid-Structure Interaction Analysis of Solid Rocket Motor with Flexible Inhibitors
NASA Technical Reports Server (NTRS)
Yang, H. Q.; West, Jeff
2014-01-01
A capability to couple NASA production CFD code, Loci/CHEM, with CFDRC's structural finite element code, CoBi, has been developed. This paper summarizes the efforts in applying the installed coupling software to demonstrate/investigate fluid-structure interaction (FSI) between pressure wave and flexible inhibitor inside reusable solid rocket motor (RSRM). First a unified governing equation for both fluid and structure is presented, then an Eulerian-Lagrangian framework is described to satisfy the interfacial continuity requirements. The features of fluid solver, Loci/CHEM and structural solver, CoBi, are discussed before the coupling methodology of the solvers is described. The simulation uses production level CFD LES turbulence model with a grid resolution of 80 million cells. The flexible inhibitor is modeled with full 3D shell elements. Verifications against analytical solutions of structural model under steady uniform pressure condition and under dynamic condition of modal analysis show excellent agreements in terms of displacement distribution and eigen modal frequencies. The preliminary coupled result shows that due to acoustic coupling, the dynamics of one of the more flexible inhibitors shift from its first modal frequency to the first acoustic frequency of the solid rocket motor.
Effect of interfacial coupling on rectification in organic spin rectifiers
NASA Astrophysics Data System (ADS)
Hu, Gui-Chao; Zuo, Meng-Ying; Li, Ying; Zhang, Zhao; Ren, Jun-Feng; Wang, Chuan-Kui
2015-07-01
The effect of interfacial coupling on rectification in an organic co-oligomer spin diode is investigated theoretically by considering spin-independent and spin-resolved couplings respectively. In the case of spin-independent coupling, an optimal interfacial coupling strength with a significant enhanced rectification ratio is found, whose value depends on the structural asymmetry of the molecule. In the case of spin-resolved coupling, we found that only the variation of the interfacial coupling with specific spin is effective to modulate the rectification, which is due to the spin-filtering property of the central asymmetric magnetic molecule. A transition of the spin-current rectification between parallel spin-current rectification and antiparallel spin-current rectification may be observed with the variation of the spin-resolved interfacial coupling. The interfacial effect on rectification is further analyzed from the spin-dependent transmission spectrum at different biases. Project supported by the National Natural Science Foundation of China (Grant No. 1374195), the Natural Science Foundation of Shandong Province, China (Grant No. ZR2014AM017), and the Excellent Young Scholars Research Fund of Shandong Normal University, China.
Interchannel coupling effects in the valence photoionization of SF6
NASA Astrophysics Data System (ADS)
Jose, Jobin; Lucchese, Robert; Rescigno, Tom
2014-05-01
The complex Kohn and polyatomic Schwinger variational techniques have been employed to illustrate the interchannel coupling correlation effects in the valence photoionization dynamics of SF6. Partial photoionization cross sections and asymmetry parameters of six valence subshells (1t1 g, 5t1 u, 1t2 u, 3eg, 1t2 g, 4t1 u) are discussed in the framework of several theoretical and experimental studies. The complex Kohn results are in rather good agreement with experimental results, indicative of the fact that the interchannel coupling effects alter the photoionization dynamics significantly. We find that the dominant effect of interchannel coupling is to reduce the magnitude of shape resonant cross sections near threshold and to induce resonant features in other channels to which resonances are coupled.
Tagliazucchi, Mario; de la Cruz, Mónica Olvera; Szleifer, Igal
2010-03-23
The competition between chemical equilibrium, for example protonation, and physical interactions determines the molecular organization and functionality of biological and synthetic systems. Charge regulation by displacement of acid-base equilibrium induced by changes in the local environment provides a feedback mechanism that controls the balance between electrostatic, van der Waals, steric interactions and molecular organization. Which strategies do responsive systems follow to globally optimize chemical equilibrium and physical interactions? We address this question by theoretically studying model layers of end-grafted polyacids. These layers spontaneously form self-assembled aggregates, presenting domains of controlled local pH and whose morphologies can be manipulated by the composition of the solution in contact with the film. Charge regulation stabilizes micellar domains over a wide range of pH by reducing the local charge in the aggregate at the cost of chemical free energy and gaining in hydrophobic interactions. This balance determines the boundaries between different aggregate morphologies. We show that a qualitatively new form of organization arises from the coupling between physical interactions and protonation equilibrium. This optimization strategy presents itself with polyelectrolytes coexisting in two different and well-defined protonation states. Our results underline the need of considering the coupling between chemical equilibrium and physical interactions due to their highly nonadditive behavior. The predictions provide guidelines for the creation of responsive polymer layers presenting self-organized patterns with functional properties and they give insights for the understanding of competing interactions in highly inhomogeneous and constrained environments such as those relevant in nanotechnology and those responsible for biological cells function.
Quantum phase transitions for two coupled cavities with dipole-interaction atoms
Tan Lei; Zhang Yuqing; Liu Wuming
2011-12-15
We investigate the quantum phase transitions for two weakly coupled atom-cavity sites. The interatomic dipole-dipole interaction is considered. Our numerical results show that the dipole-dipole interaction is a crucial parameter for the quantum phase transition. For small atom-cavity detuning, the ''superfluid'' becomes more and more obvious with the increase of the dipole-dipole interaction. In addition, the strong dipole-dipole interaction can lead the atomic excitation to be suppressed completely, and only the photonic excitation exists for the ground states. When the atom-cavity detuning is comparable with the dipole-dipole interaction, the dipole-dipole interaction enlarges the positive detunings, which is in favor of exhibiting superfluid photonic states. While for the negative detuning, the dipole-dipole interaction will reduce it, and contribute to the formation of the polaritonic insulator states. The cases for extended models have also been briefly analyzed. We also discuss how to find these novel phenomena in future experiments.
Climate-aerosol interactions over the Mediterranean region: a regional coupled modelling approach
NASA Astrophysics Data System (ADS)
Nabat, Pierre; Somot, Samuel; Mallet, Marc
2015-04-01
The Mediterranean basin is affected by numerous and various aerosols which have a high spatio-temporal variability. These aerosols directly interact with solar and thermal radiation, and indirectly with clouds and atmospheric dynamics. Therefore they can have an important impact on the regional climate. This work, located at the boundary between the ChArMEx and HyMeX programs, considers a coupled regional modeling approach in order to address the questions of the aerosol-radiation-cloud interactions with regards to the climate variability over the Mediterranean. In order to improve the characterization of Mediterranean aerosols, a new interannual monthly climatology of aerosol optical depth has been developed from a blended product based on both satellite-derived and model-simulated datasets. This dataset, available for every regional climate model over the Mediterranean for the 1979-2012 period, has been built to obtain the best possible estimate of the atmospheric aerosol content for the five species at stake (sulfate, black carbon, organic matter, desert dust and sea salt particles). Simulation ensembles, which have been carried out over the 2003-2009 period with and without aerosols, show a major impact on the regional climate. The seasonal cycle and the spatial patterns of the Mediterranean climate are significantly modified, as well as some specific situations such as the heat wave in July 2006 strengthened by the presence of desert dust particles. The essential role of the Mediterranean sea surface temperature is highlighted, and enables to understand the induced changes on air-sea fluxes and the consequences on regional climate. Oceanic convection is also strengthened by aerosols. In addition, the decrease in anthropogenic aerosols observed for more than thirty years is shown to significantly contribute to the observed Euro-Mediterranean climatic trends in terms of surface radiation and temperature. Besides, an interactive aerosol scheme has been developed
Cost effective optical coupling for polymer optical fiber communication
NASA Astrophysics Data System (ADS)
Chandrappan, Jayakrishnan; Zhang, Jing; Mohan, Ramkumar V.; Gomez, Philbert Oliver; Aung, Than Aye; Xiao, Yongfei; Ramana, Pamidighantam V.; Lau, John Hon Shing; Kwong, Dim Lee
2008-02-01
Polymer Optical Fiber (POF) optical modules are gaining momentum due to their applications in short distance communications. POFs offer more flexibility for plug and play applications and provide cost advantages. They also offer significant weight advantage in automotive and avionic networks. One of the most interesting field of application is home networking. Low cost optical components are required, since cost is a major concern in local and home networks. In this publication, a fast and easy to install, low cost solution for efficient light coupling in and out of Step Index- POF is explored. The efficient coupling of light from a large core POF to a small area detector is the major challenge faced. We simulated direct coupling, lens coupling and bend losses for step index POF using ZEMAX R optical simulation software. Simulations show that a lensed fiber tip particularly at the receiver side improves the coupling efficiency. The design is optimized for 85% coupling efficiency and explored the low cost fabrication method to implement it in the system level. The two methods followed for lens fabrication is described here in detail. The fabricated fiber lenses are characterized using a beam analyzer. The fabrication process was reiterated to optimize the lens performance. It is observed that, the fabricated lenses converge the POF output spot size by one fourth, there by enabling a higher coupling efficiency. This low cost method proves to be highly efficient and effective optical coupling scheme in POF communications.
Sakuma, Noritsugu; Ohshima, Tsubasa; Shoji, Tetsuya; Suzuki, Yoshihito; Sato, Ryota; Wachi, Ayako; Kato, Akira; Kawai, Yoichiro; Manabe, Akira; Teranishi, Toshiharu
2011-04-26
Nanocomposite magnets (NCMs) consisting of hard and soft magnetic phases are expected to be instrumental in overcoming the current theoretical limit of magnet performance. In this study, structural analyses were performed on L1(0)-FePd/α-Fe NCMs with various hard/soft volume fractions, which were formed by annealing Pd/γ-Fe(2)O(3) heterostructured nanoparticles and pure Pd nanoparticles. The sample with a hard/soft volume ratio of 82/18 formed by annealing at 773 K had the largest maximum energy product (BH(max) = 10.3 MGOe). In such a sample, the interface between the hard and soft phases was coherent and the phase sizes were optimized, both of which effectively induced exchange coupling. This exchange coupling was directly observed by visualizing the magnetic interaction between the hard and soft phases using a first-order reversal curve diagram, which is a valuable tool to improve the magnetic properties of NCMs.
Self-organized network of phase oscillators coupled by activity-dependent interactions.
Aoki, Takaaki; Aoyagi, Toshio
2011-12-01
We investigate a network of coupled phase oscillators whose interactions evolve dynamically depending on the relative phases between the oscillators. We found that this coevolving dynamical system robustly yields three basic states of collective behavior with their self-organized interactions. The first is the two-cluster state, in which the oscillators are organized into two synchronized groups. The second is the coherent state, in which the oscillators are arranged sequentially in time. The third is the chaotic state, in which the relative phases between oscillators and their coupling weights are chaotically shuffled. Furthermore, we demonstrate that self-assembled multiclusters can be designed by controlling the weight dynamics. Note that the phase patterns of the oscillators and the weighted network of interactions between them are simultaneously organized through this coevolving dynamics. We expect that these results will provide new insight into self-assembly mechanisms by which the collective behavior of a rhythmic system emerges as a result of the dynamics of adaptive interactions.
NASA Astrophysics Data System (ADS)
Larsen, Helena; Olsen, Jeppe; Hättig, Christof; Jørgensen, Poul; Christiansen, Ove; Gauss, Jürgen
1999-08-01
Static and frequency-dependent polarizabilities and first hyperpolarizabilities have been calculated for HF and Ne using full configuration interaction (FCI) and a hierarchy of coupled cluster models: coupled cluster singles (CCS), an approximate coupled cluster singles and doubles model (CC2), coupled cluster singles and doubles (CCSD), an approximate coupled cluster singles, doubles, and triples model (CC3), and coupled cluster singles, doubles, and triples (CCSDT). A previous study of BH concerning FCI benchmarking has been extended to include CC3 and static CCSDT values. Systematic improvements of the polarizabilities and the hyperpolarizabilities are found going from CCS to CCSD and from CCSD to CC3 or CCSDT. Little or no improvement of the polarizabilities and no improvement of the hyperpolarizabilities are seen when going from CCS to CC2. The CCSD results represent a significant improvement over CCS and CC2 but are again surpassed by the CC3 results which agree very well with the FCI values. The relative error for the static polarizability at the CC3 level is 0.11% for Ne and, respectively, 0.16% and 0.20% for αxx and αzz of HF. For βzzz and βzxx the errors are 0.50% and 1.7%, respectively. Only in the challenging case of BH does CCSDT improve the CC3 values. The dispersion for the polarizabilities and hyperpolarizabilities is predicted with increasing accuracy in the CCS-CC2-CCSD-CC3 sequence as expected from the increasing accuracy of the electronic excitation energies. For all molecules the effect of orbital relaxation has been investigated for the static properties. The inclusion of orbital relaxation gives results that are somewhat different from the unrelaxed results but are in general no improvement.
Effect of spin rotation coupling on spin transport
Chowdhury, Debashree Basu, B.
2013-12-15
We have studied the spin rotation coupling (SRC) as an ingredient to explain different spin-related issues. This special kind of coupling can play the role of a Dresselhaus like coupling in certain conditions. Consequently, one can control the spin splitting, induced by the Dresselhaus like term, which is unusual in a semiconductor heterostructure. Within this framework, we also study the renormalization of the spin-dependent electric field and spin current due to the k{sup →}⋅p{sup →} perturbation, by taking into account the interband mixing in the rotating system. In this paper we predict the enhancement of the spin-dependent electric field resulting from the renormalized spin rotation coupling. The renormalization factor of the spin electric field is different from that of the SRC or Zeeman coupling. The effect of renormalized SRC on spin current and Berry curvature is also studied. Interestingly, in the presence of this SRC-induced SOC it is possible to describe spin splitting as well as spin galvanic effect in semiconductors. -- Highlights: •Studied effect of spin rotation coupling on the spin electric field, spin current and Berry curvature. •In the k{sup →}⋅p{sup →} framework we study the renormalization of spin electric field and spin current. •For an inertial system we have discussed the spin splitting. •Expression for the Berry phase in the inertial system is discussed. •The inertial spin galvanic effect is studied.
Kim Halford, W; Pepping, Christopher A; Hilpert, Peter; Bodenmann, Guy; Wilson, Keithia L; Busby, Dean; Larson, Jeffry; Holman, Thomas
2015-05-01
Couple relationship education (RE) usually is conceived of as relationship enhancement for currently satisfied couples, with a goal of helping couples sustain satisfaction. However, RE also might be useful as a brief, accessible intervention for couples with low satisfaction. Two studies were conducted that tested whether couples with low relationship satisfaction show meaningful gains after RE. Study 1 was a three-condition randomized controlled trial in which 182 couples were randomly assigned to RELATE with Couple CARE (RCC), a flexible delivery education program for couples, or one of two control conditions. Couples with initially low satisfaction receiving RCC showed a moderate increase in relationship satisfaction (d=0.50) relative to the control. In contrast, couples initially high in satisfaction showed little change and there was no difference between RCC and the control conditions. Study 2 was an uncontrolled trial of the Couple Coping Enhancement Training (CCET) administered to 119 couples. Couples receiving CCET that had initially low satisfaction showed a moderate increase in satisfaction (g=.44), whereas initially highly satisfied couples showed no change. Brief relationship education can assist somewhat distressed couples to enhance satisfaction, and has potential as a cost-effective way of enhancing the reach of couple interventions.
Kim Halford, W; Pepping, Christopher A; Hilpert, Peter; Bodenmann, Guy; Wilson, Keithia L; Busby, Dean; Larson, Jeffry; Holman, Thomas
2015-05-01
Couple relationship education (RE) usually is conceived of as relationship enhancement for currently satisfied couples, with a goal of helping couples sustain satisfaction. However, RE also might be useful as a brief, accessible intervention for couples with low satisfaction. Two studies were conducted that tested whether couples with low relationship satisfaction show meaningful gains after RE. Study 1 was a three-condition randomized controlled trial in which 182 couples were randomly assigned to RELATE with Couple CARE (RCC), a flexible delivery education program for couples, or one of two control conditions. Couples with initially low satisfaction receiving RCC showed a moderate increase in relationship satisfaction (d=0.50) relative to the control. In contrast, couples initially high in satisfaction showed little change and there was no difference between RCC and the control conditions. Study 2 was an uncontrolled trial of the Couple Coping Enhancement Training (CCET) administered to 119 couples. Couples receiving CCET that had initially low satisfaction showed a moderate increase in satisfaction (g=.44), whereas initially highly satisfied couples showed no change. Brief relationship education can assist somewhat distressed couples to enhance satisfaction, and has potential as a cost-effective way of enhancing the reach of couple interventions. PMID:25892175
Gate-tunable indirect exchange interaction in spin-orbit-coupled mesoscopic rings
NASA Astrophysics Data System (ADS)
Nikoofard, H.; Heidari Semiromi, E.
2015-05-01
We study the carrier-mediated exchange interaction, the so-called Ruderman-Kittel-Kasuya-Yosida (RKKY) coupling, between two magnetic impurity moments embedded in a semiconductor mesoscopic ring. We treat the ring in the presence of an Aharonov-Bohm-type magnetic flux and the Rashba and Dresselhaus spin-orbit interactions (RSOI and DSOI). Energy eigenvalues of the system are obtained within a tight-binding framework and the strength of the indirect exchange interaction vs. RSOI strengths are plotted for different values of DSOI strength. The results show that the type of the impurity magnetic order, ferromagnetic (F) or antiferromagnetic (AF), depends on the RSOI and DSOI strengths. This leads to a full electrical control on the magnetic alignment of the system through, e.g., an external gate voltage.
Indirect exchange interaction in Rashba-spin-orbit-coupled graphene nanoflakes
NASA Astrophysics Data System (ADS)
Nikoofard, Hossein; Semiromi, Ebrahim Heidari
2016-10-01
We study the indirect exchange interaction, named Ruderman-Kittel-Kasuya-Yosida (RKKY) coupling, between localized magnetic impurities in graphene nanoflakes with zig-zag edges in the presence of the Rashba spin-orbit interaction (RSOI). We calculate the isotropic and anisotropic RKKY amplitudes by utilizing the tight-binding (TB) model. The RSOI, as a gate tunable variable, is responsible for changes of the RKKY amplitude. We conclude that there is not any switching of the magnetic order (from ferro- to antiferro-magnetic and vice versa) in such a system through the RSOI. The dependence of the RKKY amplitude on the positions of the magnetic impurities and the size of the system is studied. The symmetry breaking, which can occur due to the Rashba interaction, leads to spatial anisotropy in the RKKY amplitude and manifests as collinear and noncollinear terms. Our results show the possibility of control and manipulation of spin correlations in carbon spin-based nanodevices.
Climate-chemical interactions and greenhouse effects of trace gases
NASA Technical Reports Server (NTRS)
Shi, Guang-Yu; Fan, Xiao-Biao
1994-01-01
A completely coupled one-dimensional radiative-convective (RC) and photochemical-diffusion (PC) model has been developed recently and used to study the climate-chemical interactions. The importance of radiative-chemical interactions within the troposphere and stratosphere has been examined in some detail. We find that increases of radiatively and/or chemically active trace gases such as CO2, CH4 and N2O have both the direct effects and the indirect effects on climate change by changing the atmospheric O3 profile through their interaction with chemical processes in the atmosphere. It is also found that the climatic effect of ozone depends strongly on its vertical distribution throughout the troposphere and stratosphere, as well on its column amount in the atmosphere.
Rashba spin-orbit coupling effects in armchair graphene nanoribbons
Prabhakar, S.; Melnik, R.; Sebetci, A.
2015-03-30
We study the influence of the Rashba spin-orbit coupling effects on the electronic properties of armchair graphene nanoribbons (GNRs). By utilizing both analytical and numerical schemes, we show that the finite width of the graphene nanoribbon breaks its energy spectrum into an infinite number of bands. By considering the Rashba spin-orbit coupling term as a perturbation, we show that zero energy bands between electron and hole states at Dirac points are lifted into a finite bandgap.
Coupled Fluid-Structure Interaction Analysis of Solid Rocket Motor with Flexible Inhibitors
NASA Technical Reports Server (NTRS)
Yang, H. Q.; West, Jeff; Harris, Robert E.
2014-01-01
Flexible inhibitors are generally used in solid rocket motors (SRMs) as a means to control the burning of propellant. Vortices generated by the flow of propellant around the flexible inhibitors have been identified as a driving source of instabilities that can lead to thrust oscillations in launch vehicles. Potential coupling between the SRM thrust oscillations and structural vibration modes is an important risk factor in launch vehicle design. As a means to predict and better understand these phenomena, a multidisciplinary simulation capability that couples the NASA production CFD code, Loci/CHEM, with CFDRC's structural finite element code, CoBi, has been developed. This capability is crucial to the development of NASA's new space launch system (SLS). This paper summarizes the efforts in applying the coupled software to demonstrate and investigate fluid-structure interaction (FSI) phenomena between pressure waves and flexible inhibitors inside reusable solid rocket motors (RSRMs). The features of the fluid and structural solvers are described in detail, and the coupling methodology and interfacial continuity requirements are then presented in a general Eulerian-Lagrangian framework. The simulations presented herein utilize production level CFD with hybrid RANS/LES turbulence modeling and grid resolution in excess of 80 million cells. The fluid domain in the SRM is discretized using a general mixed polyhedral unstructured mesh, while full 3D shell elements are utilized in the structural domain for the flexible inhibitors. Verifications against analytical solutions for a structural model under a steady uniform pressure condition and under dynamic modal analysis show excellent agreement in terms of displacement distribution and eigenmode frequencies. The preliminary coupled results indicate that due to acoustic coupling, the dynamics of one of the more flexible inhibitors shift from its first modal frequency to the first acoustic frequency of the solid rocket motor
Dynamics of interacting Dicke model in a coupled-cavity array
NASA Astrophysics Data System (ADS)
Badshah, Fazal; Qamar, Shahid; Paternostro, Mauro
2014-09-01
We consider the dynamics of an array of mutually interacting cavities, each containing an ensemble of N two-level atoms. By exploring the possibilities offered by ensembles of various dimensions and a range of atom-light and photon-hopping values, we investigate the generation of multisite entanglement, as well as the performance of excitation transfer across the array, resulting from the competition between on-site nonlinearities of the matter-light interaction and intersite photon hopping. In particular, for a three-cavity interacting system it is observed that the initial excitation in the first cavity completely transfers to the ensemble in the third cavity through the hopping of photons between the adjacent cavities. Probabilities of the transfer of excitation of the cavity modes and ensembles exhibit characteristics of fast and slow oscillations governed by coupling and hopping parameters, respectively. In the large-hopping case, by seeding an initial excitation in the cavity at the center of the array, a tripartite W state, as well as a bipartite maximally entangled state, is obtained, depending on the interaction time. Population of the ensemble in a cavity has a positive impact on the rate of excitation transfer between the ensembles and their local cavity modes. In particular, for ensembles of five to seven atoms, tripartite W states can be produced even when the hopping rate is comparable to the cavity-atom coupling rate. A similar behavior of the transfer of excitation is observed for a four-coupled-cavity system with two initial excitations.
A numerical coupled model for studying air-sea-wave interaction
NASA Astrophysics Data System (ADS)
Ly, Le Ngoc
1995-10-01
A numerical coupled model of air-sea-wave interaction is developed to study the influence of ocean wind waves on dynamical, turbulent structures of the air-sea system and their impact on coupled modeling. The model equations for both atmospheric and oceanic boundary layers include equations for: (1) momentum, (2) a k-ɛ turbulence scheme, and (3) stratification in the atmospheric and oceanic boundary layers. The model equations are written in the same form for both the atmosphere and ocean. In this model, wind waves are considered as another source of turbulent energy in the upper layer of the ocean besides turbulent energy from shear production. The dissipation ɛ at the ocean surface is written as a linear combination of terms representing dissipation from mean flow and breaking waves. The ɛ from breaking waves is estimated by using similarity theory and observed data. It is written in terms of wave parameters such as wave phase speed, height, and length, which are then expressed in terms of friction velocity. Numerical experiments are designed for various geostrophic winds, wave heights, and wave ages, to study the influence of waves on the air-sea system. The numerical simulations show that the vertical profiles of ɛ in the atmospheric and oceanic boundary layers (AOBL) are similar. The magnitudes of ɛ in the oceanic surface zone are much larger than those in the atmospheric surface zone and in the interior of the oceanic boundary layer (OBL). The model predicts ɛ distributions with a surface zone of large dissipation which was not expected from similarity scaling based on observed wind stress and surface buoyancy. The simulations also show that waves have a strong influence on eddy viscosity coefficients (EVC) and momentum fluxes, and have a dominated effect on the component of fluxes in the direction of the wind. The depth of large changes in flux magnitudes and EVC in the ocean can reach to 10-20 m. The simulations of surface drift currents confirm that
Coupled-oscillator theory of dispersion and Casimir-Polder interactions.
Berman, P R; Ford, G W; Milonni, P W
2014-10-28
We address the question of the applicability of the argument theorem (of complex variable theory) to the calculation of two distinct energies: (i) the first-order dispersion interaction energy of two separated oscillators, when one of the oscillators is excited initially and (ii) the Casimir-Polder interaction of a ground-state quantum oscillator near a perfectly conducting plane. We show that the argument theorem can be used to obtain the generally accepted equation for the first-order dispersion interaction energy, which is oscillatory and varies as the inverse power of the separation r of the oscillators for separations much greater than an optical wavelength. However, for such separations, the interaction energy cannot be transformed into an integral over the positive imaginary axis. If the argument theorem is used incorrectly to relate the interaction energy to an integral over the positive imaginary axis, the interaction energy is non-oscillatory and varies as r(-4), a result found by several authors. Rather remarkably, this incorrect expression for the dispersion energy actually corresponds to the nonperturbative Casimir-Polder energy for a ground-state quantum oscillator near a perfectly conducting wall, as we show using the so-called "remarkable formula" for the free energy of an oscillator coupled to a heat bath [G. W. Ford, J. T. Lewis, and R. F. O'Connell, Phys. Rev. Lett. 55, 2273 (1985)]. A derivation of that formula from basic results of statistical mechanics and the independent oscillator model of a heat bath is presented.
Coupled-oscillator theory of dispersion and Casimir-Polder interactions
NASA Astrophysics Data System (ADS)
Berman, P. R.; Ford, G. W.; Milonni, P. W.
2014-10-01
We address the question of the applicability of the argument theorem (of complex variable theory) to the calculation of two distinct energies: (i) the first-order dispersion interaction energy of two separated oscillators, when one of the oscillators is excited initially and (ii) the Casimir-Polder interaction of a ground-state quantum oscillator near a perfectly conducting plane. We show that the argument theorem can be used to obtain the generally accepted equation for the first-order dispersion interaction energy, which is oscillatory and varies as the inverse power of the separation r of the oscillators for separations much greater than an optical wavelength. However, for such separations, the interaction energy cannot be transformed into an integral over the positive imaginary axis. If the argument theorem is used incorrectly to relate the interaction energy to an integral over the positive imaginary axis, the interaction energy is non-oscillatory and varies as r-4, a result found by several authors. Rather remarkably, this incorrect expression for the dispersion energy actually corresponds to the nonperturbative Casimir-Polder energy for a ground-state quantum oscillator near a perfectly conducting wall, as we show using the so-called "remarkable formula" for the free energy of an oscillator coupled to a heat bath [G. W. Ford, J. T. Lewis, and R. F. O'Connell, Phys. Rev. Lett. 55, 2273 (1985)]. A derivation of that formula from basic results of statistical mechanics and the independent oscillator model of a heat bath is presented.
Cao, Hongjian; Fang, Xiaoyi; Fine, Mark A; Ju, Xiaoyan; Lan, Jing; Liu, Xuanwen
2015-12-01
Employing a multicontext observational design, using a person-centered approach, and treating the marital dyad as the unit of analysis, this study examined the within-couple communication patterning of 144 Chinese newlywed couples and its association with relationship satisfaction. Latent profile analysis consistently revealed 3 profiles of spouses' interactive behaviors across contexts differing in both topic nature (i.e., problem-solving vs. social support) and initiator (i.e., husbands vs. wives): (a) traditionally undemonstrative profile, (b) emotionally quarrelling profile, and (c) warmly supportive profile. The prevalence of communication profiles changed markedly with the nature of the discussion topic and the topic initiator. Further, using latent class analysis, we classified couples into subgroups based on their identified profile memberships across contexts (i.e., consistency of interaction mode across contexts). Three classes were identified: (a) consistently quarrelling class, (b) consistently supportive class, and (c) modestly traditional class. Both the consistently supportive class and the modestly traditional class reported significantly higher levels of marital satisfaction than did the consistently quarrelling class.
Exploring the effects of sexual desire discrepancy among married couples.
Willoughby, Brian J; Farero, Adam M; Busby, Dean M
2014-04-01
Previous studies have found associations between the individual discrepancy of desired sexual frequency and actual sexual frequency and relational outcomes among premarital couples. The present study extended this research by using a sample of 1,054 married couples to explore how actor and partner individual sexual desire discrepancy (SDD) scores were associated with relationship satisfaction, stability, communication, and conflict during marriage. All participants took an online survey which assessed both couple sexual dynamics and relationship outcomes. Findings suggested that higher actor individual SDD was generally associated with negative relational outcomes, including lower reported relationship satisfaction, stability, and more reported couple conflict. These effects were found after controlling for background factors, baseline sexual frequency and desire, and couple desire discrepancies. Some partner effects were also found and were generally in the same direction. Marital length did not moderate the effects found although gender moderated associations between individual SDD and reported couple communication. Negative associations between individual SDD and communication were particularly strong when the husband reported high discrepancies between desired and actual sexual frequency. Results suggested that higher individual sexual desire discrepancies among married individuals may undermine relationship well-being. Applications of these findings to a clinical setting are also discussed. PMID:24045904
NASA Astrophysics Data System (ADS)
Chiolerio, Alessandro; Allia, Paolo; Graziano, Mariagrazia
2012-09-01
Physical limitations foreshadow the eventual end to traditional Complementary Metal Oxide Semiconductor (CMOS) scaling. Therefore, interest has turned to various materials and technologies aimed to succeed to traditional CMOS. Magnetic Quantum dot Cellular Automata (MQCA) are one of these technologies. Working MQCA arrays require very complex techniques and an excellent control on the geometry of the nanomagnets and on the quality of the magnetic thin film, thus limiting the possibility for MQCA of representing a definite solution to cost-effective, high density and low power consumption device demand. Counter-intuitively, moving towards bigger sizes and lighter technologies it is still possible to develop multi-state logic devices, as we demonstrated, whose main advantage is cost-effectiveness. Applications may be seen in low cost logic devices where integration and computational power are not the main issue, eventually using flexible substrates and taking advantage of the intrinsic mechanical toughness of systems where long range interactions do not need wirings. We realized cobalt micrometric MQCA arrays by means of Electron Beam Lithography, exploiting cost-effective processes such as lift-off and RF sputtering that usually are avoided due to their low control on array geometry and film roughness. Information relative to the magnetic configuration of MQCA elements including their eventual magnetic interactions was obtained from Magnetic Force Microscope (MFM) images, enhanced by means of a numerical procedure and presented in differential maps. We report the existence of bi-stable magnetic patterns, as detected by MFM while sampling the z-component of magnetic induction field, arising from dipolar inter-element magnetostatic coupling, able to store and propagate binary information. This is achieved despite the array quality and element magnetic state, which are low and multi-domain, respectively. We discuss in detail shape, inter-element spacing and dot profile
Magnetic domain wall creep in the presence of an effective interlayer coupling field
NASA Astrophysics Data System (ADS)
Metaxas, P. J.; Jamet, J. P.; Ferré, J.; Rodmacq, B.; Dieny, B.; Stamps, R. L.
We investigate thermally activated domain wall creep in a system consisting of two ultrathin Co layers with perpendicular anisotropy coupled antiferromagnetically through a 4 nm thick Pt spacer layer. The field driven dynamics of domain walls in the softer Co layer have been measured while keeping the harder Co layer negatively saturated. The effect of the interlayer interaction on the soft layer is interpreted in terms of an effective coupling field, HJ, which results in an asymmetry between the domain wall speeds measured under positive and negative driving fields. We show that creep theory remains valid to describe the observed wall motion when the effective coupling field is included in the creep velocity law as a component of the total field acting on the wall. Using the resultant modified creep expression, we determine a value for the effective coupling field which is consistent with that measured from the shift of the soft layer's minor hysteresis loop. The net antiferromagnetic coupling is attributed to a combination of RKKY and orange-peel coupling.
Thermodynamics of interacting cold atomic Fermi gases with spin-orbit coupling
NASA Astrophysics Data System (ADS)
Jensen, Scott; Alhassid, Yoram; Gilbreth, Christopher
New physics is suggested with the prediction of novel phases in cold atom systems when a synthetic spin-orbit coupling is introduced. In particular, recent studies show that a new type of Bose-Einstein condensate, termed Rashbon-BEC, is formed when a generalized Rashba spin-orbit term is present. The Rashbon-BEC phase can be obtained by tuning the spin-orbit coupling strength even in the case of finite negative scattering length. This stands in contrast to the BCS-BEC crossover in the absence of spin-orbit coupling where a negative scattering length is associated with BCS physics, and its divergence signals the crossover. In our work we apply finite-temperature quantum Monte Carlo methods to a spherical Rashba spin-orbit coupled two-species Fermi gas with contact s-wave interaction in three dimensions. We will discuss the phase diagram for this system, and its crossover behavior from BCS to Rashbon-BEC. This work was supported in part by the Department of Energy Grant No. DE-FG-0291-ER-40608.
Lewis, M.W.; Kashiwa, B.A.; Meier, R.W.; Bishop, S.
1994-08-01
Two- and three-dimensional fluid-structure interaction computer programs for the simulation of nonlinear dynamics were developed and applied to a number of problems. The programs were created by coupling Arbitrary Lagrangian-Eulerian finite volume fluid dynamics programs with strictly Lagrangian finite element structural dynamics programs. The resulting coupled programs can use either fully explicit or implicit time integration. The implicit time integration is accomplished by iterations of the fluid dynamics pressure solver and the structural dynamics system solver. The coupled programs have been used to solve problems involving incompressible fluids, membrane and shell elements, compressible multiphase flows, explosions in both air and water, and large displacements. In this paper, we present the approach used for the coupling and describe test problems that verify the two-dimensional programs against an experiment and an analytical linear problem. The experiment involves an explosion underwater near an instrumented thin steel plate. The analytical linear problem is the vibration of an infinite cylinder surrounded by an incompressible fluid to a given radius.
NASA Astrophysics Data System (ADS)
Lewis, M. W.; Kashiwa, B. A.; Meier, R. W.; Bishop, S.
1994-07-01
Two- and three-dimensional fluid-structure interaction computer programs for the simulation of nonlinear dynamics were developed and applied to a number of problems. The programs were created by coupling Arbitrary Lagrangian-Eulerian finite volume fluid dynamics programs with strictly Lagrangian finite element structural dynamics programs. The resulting coupled programs can use either fully explicit or implicit time integration. The implicit time integration is accomplished by iterations of the fluid dynamics pressure solver and the structural dynamics system solver. The coupled programs have been used to solve problems involving incompressible fluids, membrane and shell elements, compressible multiphase flows, explosions in both air and water, and large displacements. In this paper, we present the approach used for the coupling and describe test problems that verify the two-dimensional programs against an experiment and an analytical linear problem. The experiment involves an explosion underwater near an instrumented thin steel plate. The analytical linear problem is the vibration of an infinite cylinder surrounded by an incompressible fluid to a given radius.
NASA Astrophysics Data System (ADS)
Mehdipour, M.; Shokrollahi, H.; Bahadoran, A.
2014-09-01
Ferromagnetic SrFe12O19-ZnFe2O4 nanostructure composite particles were synthesized by co-precipitation of chloride salts, in different stoichiometric ratios, by addition of sodium hydroxide solution. The resulting precursors were heat treated at temperatures in the range 800-1200°C for 4 h. Exchange interactions of the nanostructure composite particles were studied by use of exchange-coupling theory and plots of magnetic hysteresis. On the basis of exchange-coupling theory, the exchange interaction can be improved by increasing the soft phase content within the hard matrix. As temperature and soft phase ratio increase, the exchange interaction increases because of exchange length enhancement. The modified Brown's equation was also used to analyze the effects of exchange coupling on coercivity.
Light-matter decoupling in the deep strong coupling regime: the breakdown of the Purcell effect.
De Liberato, Simone
2014-01-10
Improvements in both the photonic confinement and the emitter design have led to a steady increase in the strength of the light-matter coupling in cavity quantum electrodynamics experiments. This has allowed us to access interaction-dominated regimes in which the state of the system can only be described in terms of mixed light-matter excitations. Here we show that, when the coupling between light and matter becomes strong enough, this picture breaks down, and light and matter degrees of freedom totally decouple. A striking consequence of such a counterintuitive phenomenon is that the Purcell effect is reversed and the spontaneous emission rate, usually thought to increase with the light-matter coupling strength, plummets instead for large enough couplings.
Evidence for an interaction of neuronostatin with the orphan G protein-coupled receptor, GPR107.
Yosten, Gina L C; Redlinger, Lauren J; Samson, Willis K
2012-11-01
Neuronostatin, derived from the somatostatin preprohormone, is a recently described peptide that is produced by several tissues involved in cardiovascular regulation and metabolism, including the hypothalamus. Injection of neuronostatin into the lateral cerebroventricle led to a dose-related increase in mean arterial pressure (MAP) in rats. Any attempt to inhibit the production of neuronostatin would alter somatostatin production as well, making determination of the physiological relevance of the peptide's pharmacologic effects by compromise of production approaches impossible. Therefore, we employed an alternative approach to identify and compromise the production of the neuronostatin receptor. Because neuronostatin was shown to signal via a PKA-dependent mechanism, we hypothesized that the neuronostatin receptor was a G protein-coupled receptor (GPCR), in particular, one of the orphan GPCRs for which the ligand is unknown. Therefore, we screened neuronostatin-responsive tissues, including hypothalamus, heart, pancreatic α-cells, and the gastric tumor cell line KATOIII, for expression of orphan GPCRs. Four orphan GPCRs were expressed by all cell types, including GPR56 and GPR107. Knockdown of GPR107, but not GPR56 or GPR146, led to a loss of responsiveness to neuronostatin by KATOIII cells. Rats injected with siRNA directed against GPR107 (2 μg/day for 2 days) into the lateral cerebroventricle did not exhibit an increase in MAP in response to neuronostatin treatment. Rats with compromised GPR107 expression also displayed blunted reactivity in a baroreflex sensitivity test, indicating that GPR107 and neuronostatin may be important regulators of cardiovascular function. Thus, GPR107 is a promising candidate receptor for neuronostatin, and neuronostatin, interacting with GPR107, may play an important role in the central control of cardiovascular function. PMID:22933024
Wilkes, Daniel R; Duncan, Alec J
2015-04-01
This paper presents a numerical model for the acoustic coupled fluid-structure interaction (FSI) of a submerged finite elastic body using the fast multipole boundary element method (FMBEM). The Helmholtz and elastodynamic boundary integral equations (BIEs) are, respectively, employed to model the exterior fluid and interior solid domains, and the pressure and displacement unknowns are coupled between conforming meshes at the shared boundary interface to achieve the acoustic FSI. The low frequency FMBEM is applied to both BIEs to reduce the algorithmic complexity of the iterative solution from O(N(2)) to O(N(1.5)) operations per matrix-vector product for N boundary unknowns. Numerical examples are presented to demonstrate the algorithmic and memory complexity of the method, which are shown to be in good agreement with the theoretical estimates, while the solution accuracy is comparable to that achieved by a conventional finite element-boundary element FSI model.
NASA Astrophysics Data System (ADS)
Wang, Peng-Fei; Ruan, Xiao-Dong; Xu, Zhong-Bin; Fu, Xin
2015-11-01
The Hong-Strogatz (HS) model of globally coupled phase oscillators with attractive and repulsive interactions reflects the fact that each individual (oscillator) has its own attitude (attractive or repulsive) to the same environment (mean field). Previous studies on HS model focused mainly on the stable states on Ott-Antonsen (OA) manifold. In this paper, the eigenvalues of the Jacobi matrix of each fixed point in HS model are explicitly derived, with the aim to understand the local dynamics around each fixed point. Phase transitions are described according to relative population and coupling strength. Besides, the dynamics off OA manifold is studied. Supported by the National Basic Research Program of China under Grant No. 2015CB057301, the Applied Research Project of Public Welfare Technology of Zhejiang Province under Grant No. 201SC31109 and China Postdoctoral Science Foundation under Grant No. 2014M560483
Transonic shock oscillations calculated with a new interactive boundary layer coupling method
NASA Technical Reports Server (NTRS)
Edwards, John W.
1993-01-01
A new viscous-inviscid interactive coupling method is described with the aim of allowing time-accurate computation of unsteady transonic flows involving separation and reattachment. A lag-entrainment integral boundary layer method is used in conjunction with a transonic small disturbance potential code. The solutions are coupled with a novel variable gain, integral control method for the boundary layer displacement thickness. Efficient and robust computations of steady and unsteady separated flows, including steady separation bubbles and self-excited shock-induced oscillations, are presented. The buffet onset boundary for the NACA 0012 airfoil is accurately predicted and shown computationally to be a Hopf bifurcation. Shock-induced oscillations are also presented for the 18 percent thick circular arc airfoil. The oscillation onset boundaries and frequencies are accurately predicted, as is the experimentally observed hysteresis of the oscillations with Mach number; this latter stability boundary is identified as a jump phenomenon.
Standing wave plasmon modes interact in an antenna-coupled nanowire.
Day, Jared K; Large, Nicolas; Nordlander, Peter; Halas, Naomi J
2015-02-11
In a standing wave optical cavity, the coupling of cavity modes, for example, through a nonlinear medium, results in a rich variety of nonlinear dynamical phenomena, such as frequency pushing and pulling, mode-locking and pulsing, modal instabilities, even complex chaotic behavior. Metallic nanowires of finite length support a hierarchy of longitudinal surface plasmon modes with standing wave properties: the plasmonic analog of a Fabry-Pérot cavity. Here we show that positioning the nanowire within the gap of a plasmonic nanoantenna introduces a passive, hybridization-based coupling of the standing-wave nanowire plasmon modes with the antenna structure, mediating an interaction between the nanowire plasmon modes themselves. Frequency pushing and pulling, and the enhancement and suppression of specific plasmon modes, can be controlled and manipulated by nanoantenna position and shape.
Wilkes, Daniel R; Duncan, Alec J
2015-04-01
This paper presents a numerical model for the acoustic coupled fluid-structure interaction (FSI) of a submerged finite elastic body using the fast multipole boundary element method (FMBEM). The Helmholtz and elastodynamic boundary integral equations (BIEs) are, respectively, employed to model the exterior fluid and interior solid domains, and the pressure and displacement unknowns are coupled between conforming meshes at the shared boundary interface to achieve the acoustic FSI. The low frequency FMBEM is applied to both BIEs to reduce the algorithmic complexity of the iterative solution from O(N(2)) to O(N(1.5)) operations per matrix-vector product for N boundary unknowns. Numerical examples are presented to demonstrate the algorithmic and memory complexity of the method, which are shown to be in good agreement with the theoretical estimates, while the solution accuracy is comparable to that achieved by a conventional finite element-boundary element FSI model. PMID:25920865
Feller, David Peterson, Kirk A.; Davidson, Ernest R.
2014-09-14
A systematic sequence of configuration interaction and coupled cluster calculations were used to describe selected low-lying singlet and triplet vertically excited states of ethylene with the goal of approaching the all electron, full configuration interaction/complete basis set limit. Included among these is the notoriously difficult, mixed valence/Rydberg {sup 1}B{sub 1u} V state. Techniques included complete active space and iterative natural orbital configuration interaction with large reference spaces which led to variational spaces of 1.8 × 10{sup 9} parameters. Care was taken to avoid unintentionally biasing the results due to the widely recognized sensitivity of the V state to the details of the calculation. The lowest vertical and adiabatic ionization potentials to the {sup 2}B{sub 3u} and {sup 2}B{sub 3} states were also determined. In addition, the heat of formation of twisted ethylene {sup 3}A{sub 1} was obtained from large basis set coupled cluster theory calculations including corrections for core/valence, scalar relativistic and higher order correlation recovery.
NASA Astrophysics Data System (ADS)
Rury, Aaron S.
2016-06-01
This study reports experimental, computational, and theoretical evidence for a previously unobserved coherent phonon-phonon interaction in an organic solid that can be described by the application of Fano's analysis to a case without the presence of a continuum. Using Raman spectroscopy of the hydrogen-bonded charge-transfer material quinhydrone, two peaks appear near 700 cm-1 we assign as phonons whose position and line-shape asymmetry depend on the sample temperature and light scattering excitation energy. Density functional theory calculations find two nearly degenerate phonons possessing frequencies near the values found in experiment that share similar atomic motion out of the aromatic plane of electron donor and acceptor molecules of quinhydrone. Further analytical modeling of the steady-state light scattering process using the Peierls-Hubbard Hamiltonian and time-dependent perturbation theory motivates assignment of the physical origin of the asymmetric features of each peak's line shape to an interaction between two discrete phonons via nonlinear electron-phonon coupling. In the context of analytical model results, characteristics of the experimental spectra upon 2.33 eV excitation of the Raman scattering process are used to qualify the temperature dependence of the magnitude of this coupling in the valence band of quinhydrone. These results broaden the range of phonon-phonon interactions in materials in general while also highlighting the rich physics and fundamental attributes specific to organic solids that may determine their applicability in next generation electronics and photonics technologies.
Interaction of Galphaq and Kir3, G protein-coupled inwardly rectifying potassium channels.
Kawano, Takeharu; Zhao, Peng; Floreani, Christina V; Nakajima, Yasuko; Kozasa, Tohru; Nakajima, Shigehiro
2007-04-01
Activation of substance P receptors, which are coupled to Galpha(q), inhibits the Kir3.1/3.2 channels, resulting in neuronal excitation. We have shown previously that this channel inactivation is not caused by reduction of the phosphatidylinositol 4,5-bisphosphate level in membrane. Moreover, Galpha(q) immunoprecipitates with Kir3.2 (J Physiol 564:489-500, 2005), suggesting that Galpha(q) interacts with Kir3.2. Positive immunoprecipitation, however, does not necessarily indicate direct interaction between the two proteins. Here, the glutathione transferase pull-down assay was used to investigate interaction between Galpha(q) and the K(+) channels. We found that Galpha(q) interacted with N termini of Kir3.1, Kir3.2, and Kir3.4. However, Galpha(q) did not interact with the C terminus of any Kir3 or with the C or N terminus of Kir2.1. TRPC6 is regulated by the signal initiated by Galpha(q). Immunoprecipitation, however, showed that Galpha(q) did not interact with TRPC6. Thus, the interaction between Galpha(q) and the Kir3 N terminus is quite specific. This interaction occurred in the presence of GDP or GDP-AlF(-)(4). The Galpha(q) binding could take place somewhere between residues 51 to 90 of Kir3.2; perhaps the segment between 81 to 90 residues is crucial. Gbetagamma, which is known to bind to N terminus of Kir3, did not compete with Galpha(q) for the binding, suggesting that these two binding regions are different. These findings agree with the hypothesis (J Physiol 564:489-500, 2005) that the signal to inactivate the Kir3 channel could be mainly transmitted directly from Galpha(q) to Kir3. PMID:17296805
Azar, Richard Julian Head-Gordon, Martin
2015-05-28
Your correspondents develop and apply fully nonorthogonal, local-reference perturbation theories describing non-covalent interactions. Our formulations are based on a Löwdin partitioning of the similarity-transformed Hamiltonian into a zeroth-order intramonomer piece (taking local CCSD solutions as its zeroth-order eigenfunction) plus a first-order piece coupling the fragments. If considerations are limited to a single molecule, the proposed intermolecular similarity-transformed perturbation theory represents a frozen-orbital variant of the “(2)”-type theories shown to be competitive with CCSD(T) and of similar cost if all terms are retained. Different restrictions on the zeroth- and first-order amplitudes are explored in the context of large-computation tractability and elucidation of non-local effects in the space of singles and doubles. To accurately approximate CCSD intermolecular interaction energies, a quadratically growing number of variables must be included at zeroth-order.
Effects of interleaflet coupling on the morphologies of multicomponent lipid bilayer membranes
NASA Astrophysics Data System (ADS)
Funkhouser, Chloe M.; Mayer, Michael; Solis, Francisco J.; Thornton, K.
2013-01-01
We investigate dynamical and stationary compositional and surface morphologies in macroscopically phase-separating multicomponent lipid bilayer membranes using a computational model. We employ a phase-field method for the description of the coexisting phases and treat the two leaflets individually while including interleaflet interactions. The compositional evolution of the two leaflets is coupled to the shape evolution of the membrane via a Helfrich free energy with a composition-dependent spontaneous curvature. We investigate the effects of the interleaflet interaction on the dynamics and stationary states of a system favoring nonzero spontaneous curvatures. Morphological phase diagrams are mapped in composition space using three different interleaflet coupling strengths. We find that characteristics sensitive to the coupling strength include the time required to develop regions of fully separated phases, the prevalence of a stripe morphology, and the shifting of phase compositions to accommodate energetically favorable interactions across leaflets. Characteristics found to be robust with respect to coupling strength include (1) the stripe morphology is favored at nearly equal mixtures and (2) phase separation is prevented in systems where a pair of phases that preferentially interact across leaflets together occupy nearly all or none of the membrane.
Georgelin, E; Loeuille, N
2014-04-01
Understanding the interplay of antagonistic and mutualistic interactions is an important challenge for predicting the fate of ecological communities. So far, studies of propagation of disturbances have focused on a single interaction type (antagonistic or mutualistic), leaving out part of the natural diversity. We develop a model that describes the dynamics of a plant species interacting with one antagonistic (e.g. an herbivore) and one mutualistic (e.g. a pollinator) species confronted to a perturbation to assess how each interaction type will affect the other. We analyze the effect of additional mortality as a press perturbation acting on the plant's partners. We study how the intensity of the disturbance and the relative sensitivities of partner species determine community structure, as well as extinction orders. We show that due to indirect effects between the two types of interactions, additional mortality on both pollinators and herbivores can either decrease or increase their densities. The presence of pollinators can stabilize the antagonistic interaction by preventing cyclic dynamics in the plant-herbivore system. We propose explanatory mechanisms based on indirect effects and discuss the implications of our results for the conservation of interactions and communities. Our results suggest that, in agricultural landscapes, direct effects of insecticides on herbivore densities can be fully offset by indirect effects mediated through pollinators. The loss of pollinators, due to insecticide use, can also destabilize the dynamics of insect herbivores. PMID:24368126
NASA Astrophysics Data System (ADS)
Seo, H.; Miller, A. J.; Norris, J. R.
2015-12-01
The US West Coast coastal oceans feature energetic mesoscale eddies. The associated sea surface temperature (SST) and surface current modify the wind stress, leading to significant dynamic feedback on to the air-sea coupled system. Dynamics of the interaction and impacts on the regional coastal climate are however not well understood; this is an important research question for regional modeling studies for the coastal climate. A high-resolution (7km) SCOAR regional air-sea coupled climate model is used to investigate this question by implementing a novel model coupling technique that separates spatial scale of air-sea interaction. It allows the large-scale coupling effect to be preserved while suppressing the eddy-driven coupling via interactive spatial smoothing of SST and surface current. When the eddy-induced surface current is allowed to modify the wind stress, the eddy kinetic energy (EKE) is reduced by 42%, and this is primarily due to enhanced surface eddy drag. In contrast, the eddy-induced SST-wind coupling has little impact on the EKE. Eddies also modify the Ekman pumping; the resultant Ekman pumping velocity due to surface current attenuates the amplitude of eddies while the SST-induced Ekman pumping affects the propagation of eddies. Rectified change in time-mean SST is determined by the altered offshore temperature advection by the mean and eddy currents, but the magnitude of the mean SST change is greater with the eddy-induced current effect. The subsequent influence on the downstream winter rainfall variability on the US West Coast is stronger with the eddy-induced SST effect because of the proximity of SST anomalies to the coasts. The strong dynamical response in the coastal climate system to the eddy-driven air-sea interaction suggests that the fine-scale air-sea coupling should be better represented in the regional climate modeling studies for the coastal environments and the marine weather.
Baddour, Frederick G; Fiedler, Stephanie R; Shores, Matthew P; Golen, James A; Rheingold, Arnold L; Doerrer, Linda H
2013-05-01
A series of Pt-based heterobimetallic lantern complexes of the form [PtM(SAc)4(OH2)] (M = Co, 1; Ni, 2; Zn, 3) were prepared using a facile, single-step procedure. These hydrated species were reacted with 3-nitropyridine (3-NO2py) to prepare three additional lantern complexes, [PtM(SAc)4(3-NO2py)] (M = Co, 4; Ni, 5; Zn, 6), or alternatively dried in vacuo to the dehydrated species [PtM(SAc)4] (M = Co, 7; Ni, 8; Zn, 9). The Co- and Ni-containing species exhibit Pt-M bonding in solution and the solid state. In the structurally characterized compounds 1-6, the lantern units form dimers in the solid state via a short Pt···Pt metallophilic interaction. Antiferromagnetic coupling between 3d metal ions in the solid state through noncovalent metallophilic interactions was observed for all the paramagnetic lantern complexes prepared, with J-coupling values of -12.7 cm(-1) (1), -50.8 cm(-1) (2), -6.0 cm(-1) (4), and -12.6 cm(-1) (5). The Zn complexes 3 and 6 also form solid-state dimers, indicating that the formation of short Pt···Pt interactions in these complexes is not predicated on the presence of a paramagnetic 3d metal ion. These contacts and the resultant antiferromagnetic coupling are also not unique to heterobimetallic lantern complexes with axially coordinated H2O or the previously reported thiobenzoate supporting ligand.
Pacemaking through Ca2+ stores interacting as coupled oscillators via membrane depolarization.
Imtiaz, Mohammad S; Zhao, Jun; Hosaka, Kayoko; von der Weid, Pierre-Yves; Crowe, Melissa; van Helden, Dirk F
2007-06-01
This study presents an investigation of pacemaker mechanisms underlying lymphatic vasomotion. We tested the hypothesis that active inositol 1,4,5-trisphosphate receptor (IP(3)R)-operated Ca(2+) stores interact as coupled oscillators to produce near-synchronous Ca(2+) release events and associated pacemaker potentials, this driving action potentials and constrictions of lymphatic smooth muscle. Application of endothelin 1 (ET-1), an agonist known to enhance synthesis of IP(3), to quiescent lymphatic smooth muscle syncytia first enhanced spontaneous Ca(2+) transients and/or intracellular Ca(2+) waves. Larger near-synchronous Ca(2+) transients then occurred leading to global synchronous Ca(2+) transients associated with action potentials and resultant vasomotion. In contrast, blockade of L-type Ca(2+) channels with nifedipine prevented ET-1 from inducing near-synchronous Ca(2+) transients and resultant action potentials, leaving only asynchronous Ca(2+) transients and local Ca(2+) waves. These data were well simulated by a model of lymphatic smooth muscle with: 1), oscillatory Ca(2+) release from IP(3)R-operated Ca(2+) stores, which causes depolarization; 2), L-type Ca(2+) channels; and 3), gap junctions between cells. Stimulation of the stores caused global pacemaker activity through coupled oscillator-based entrainment of the stores. Membrane potential changes and positive feedback by L-type Ca(2+) channels to produce more store activity were fundamental to this process providing long-range electrochemical coupling between the Ca(2+) store oscillators. We conclude that lymphatic pacemaking is mediated by coupled oscillator-based interactions between active Ca(2+) stores. These are weakly coupled by inter- and intracellular diffusion of store activators and strongly coupled by membrane potential. Ca(2+) store-based pacemaking is predicted for cellular systems where: 1), oscillatory Ca(2+) release induces depolarization; 2), membrane depolarization provides positive
Effect of Coriolis coupling in chemical reaction dynamics.
Chu, Tian-Shu; Han, Ke-Li
2008-05-14
It is essential to evaluate the role of Coriolis coupling effect in molecular reaction dynamics. Here we consider Coriolis coupling effect in quantum reactive scattering calculations in the context of both adiabaticity and nonadiabaticity, with particular emphasis on examining the role of Coriolis coupling effect in reaction dynamics of triatomic molecular systems. We present the results of our own calculations by the time-dependent quantum wave packet approach for H + D2 and F(2P3/2,2P1/2) + H2 as well as for the ion-molecule collisions of He + H2 +, D(-) + H2, H(-) + D2, and D+ + H2, after reviewing in detail other related research efforts on this issue.
NASA Astrophysics Data System (ADS)
Zeb, M. Ahsan; Kee, Hae-Young
2012-08-01
There has been a rapidly growing interest in the interplay between spin-orbit coupling (SOC) and the Hubbard interaction U in correlated materials. A current consensus is that the stronger the SOC, the smaller is the critical interaction Uc required for a spin-orbit Mott insulator, because the atomic SOC splits a band into different total angular momentum bands, narrowing the effective bandwidth. It was further claimed that at large enough SOC, the stronger the SOC, the weaker the Uc, because in general the effective SOC is enhanced with increasing electron-electron interaction strength. Contrary to this expectation, we find that, in orthorhombic perovskite oxides (Pbnm), the stronger the SOC, the bigger the Uc. This originates from a line of Dirac nodes in Jeff=1/2 bands near the Fermi level, inherited from a combination of the lattice structure and a large SOC. Due to this protected line of nodes, there are small hole and electron pockets in SrIrO3, and such a small density of states makes the Hubbard interaction less efficient in building a magnetic insulator. The full phase diagram in U vs SOC is obtained, where nonmagnetic semimetal, magnetic metal, and magnetic insulator are found. Magnetic ordering patterns beyond Uc are also presented. We further discuss implications of our finding in relation to other perovskites such as SrRhO3 and SrRuO3.
NASA Astrophysics Data System (ADS)
Song, J.; Wang, Z.
2013-12-01
Studying urban land-atmospheric interactions by coupling an urban canopy model with a single column atmospheric models Jiyun Song and Zhi-Hua Wang School of Sustainable Engineering and the Built Environment, Arizona State University, PO Box 875306, Tempe, AZ 85287-5306 Landuse landcover changes in urban area will modify surface energy budgets, turbulent fluxes as well as dynamic and thermodynamic structures of the overlying atmospheric boundary layer (ABL). In order to study urban land-atmospheric interactions, we coupled a single column atmospheric model (SCM) to a cutting-edge single layer urban canopy model (SLUCM). Modification of surface parameters such as the fraction of vegetation and engineered pavements, thermal properties of building and pavement materials, and geometrical features of street canyon, etc. in SLUCM dictates the evolution of surface balance of energy, water and momentum. The land surface states then provide lower boundary conditions to the overlying atmosphere, which in turn modulates the modification of ABL structure as well as vertical profiles of temperature, humidity, wind speed and tracer gases. The coupled SLUCM-SCM model is tested against field measurements of surface layer fluxes as well as profiles of temperature and humidity in the mixed layer under convective conditions. After model test, SLUCM-SCM is used to simulate the effect of changing urban land surface conditions on the evolution of ABL structure and dynamics. Simulation results show that despite the prescribed atmospheric forcing, land surface states impose significant impact on the physics of the overlying vertical atmospheric layer. Overall, this numerical framework provides a useful standalone modeling tool to assess the impacts of urban land surface conditions on the local hydrometeorology through land-atmospheric interactions. It also has potentially far-reaching implications to urban ecohydrological services for cities under future expansion and climate challenges.
A Coupled Modeling Approach for Root-Soil Interaction Processes Using DuMuX
NASA Astrophysics Data System (ADS)
Schröder, N.; Helmig, R.; Flemisch, B.; Koch, T.
2015-12-01
The water and nutrient uptake of plant roots in soils have a crucial influence on soil physical processes. The interacting processes between plant roots and soil are important for several agricultural problems, for example water management or leaching of pesticides. However, the coupled mechanisms of local soil and root water flow, transport of dissolved substances, root growth, and root uptake are difficult to measure and thus experimental data are rare. Numerical models can be used to understand these complex soil-root systems and help to analyze and interpret experimental measurements. The model approach presented here couples a root system and a soil model. Crucial for this approach is the 1D-3D grid coupling which combines a 1D network grid (root system) with the 3D soil grid. Based on that grid coupling, local processes are defined, for instance the local water uptake of a single root segment. Here, the interface conditions between roots and soil play a major role and we use local grid refinement strategies to better resolve these interface processes. This grid refinement of the 3D soil grid is based on the root network (1D grid) and adapts if root growth occurs. It offers the possibility to describe processes in the soil-plant continuum in a more physical manner avoiding empirical descriptions of root water uptake as a function of bulk matric potential, osmotic potential, root length density, and transpiration rate. Our coupling approach is included into the framework of DuMux, an open-source simulator for flow and transport processes in porous media. This implementation combines biological, chemical and physical processes in soil, inside roots, and at root-soil interfaces, and is contained in a sustainable and consistent framework for the implementation. We will show example simulations describing water flow, solute transport and root growth in a soil-root system.
Effects of economic interactions on credit risk
NASA Astrophysics Data System (ADS)
Hatchett, J. P. L.; Kühn, R.
2006-03-01
We study a credit-risk model which captures effects of economic interactions on a firm's default probability. Economic interactions are represented as a functionally defined graph, and the existence of both cooperative and competitive business relations is taken into account. We provide an analytic solution of the model in a limit where the number of business relations of each company is large, but the overall fraction of the economy with which a given company interacts may be small. While the effects of economic interactions are relatively weak in typical (most probable) scenarios, they are pronounced in situations of economic stress, and thus lead to a substantial fattening of the tails of loss distributions in large loan portfolios. This manifests itself in a pronounced enhancement of the value at risk computed for interacting economies in comparison with their non-interacting counterparts.
Nater, Urs M.; Schaer, Marcel; La Marca, Roberto; Bodenmann, Guy; Ehlert, Ulrike; Heinrichs, Markus
2013-01-01
Unhappy couple relationships are associated with impaired individual health, an effect thought to be mediated through ongoing couple conflicts. Little is known, however, about the underlying mechanisms regulating psychobiological stress, and particularly autonomic nervous system (ANS) reactivity, during negative couple interaction. In this study, we tested the effects of the neuropeptide oxytocin on ANS reactivity during couple conflict in a standardized laboratory paradigm. In a double-blind, placebo-controlled design, 47 heterosexual couples (total n = 94) received oxytocin or placebo intranasally prior to instructed couple conflict. Participants’ behavior was videotaped and salivary alpha-amylase (sAA), a measure of sympathetic activity, and emotional arousal were repeatedly measured during the experiment. Oxytocin significantly reduced sAA during couple conflict in women, whereas men showed increases in sAA levels (sex × group interaction: B = −49.36, t = −2.68, P = 0.009). In men, these increases were related to augmented emotional arousal (r = 0.286, P = 0.028) and more positive behavior (r = 0.291, P = 0.026), whereas there was no such association in women. Our results imply sex-specific effects of oxytocin on sympathetic activity, to negative couple interaction, with the neuropeptide reducing sAA responses and emotional arousal in women while increasing them in men. PMID:22842905
Coupled-cluster theory of a gas of strongly-interacting electrons in the dilute limit
Mihaila, Bodgan; Cardenas, Andres L
2008-01-01
We study the ground-state properties of a dilute gas of strongly-interacting fermions in the framework of the coupled-cluster expansion (CCE). We demonstrate that properties such as universality, opening of a gap in the excitation spectrum and applicability of s-wave approximations appear naturally in the CCE approach. In the zero-density limit, we show that the ground-state energy density depends on only one parameter which in turn may depend at most on the spatial dimensionality of the system.
Higher Spin Interactions from Conformal Field Theory: The Complete Cubic Couplings.
Sleight, Charlotte; Taronna, Massimo
2016-05-01
In this Letter we provide a complete holographic reconstruction of the cubic couplings in the minimal bosonic higher spin theory in (d+1)-dimensional anti- de Sitter space. For this purpose, we also determine the operator-product expansion coefficients of all single-trace conserved currents in the d-dimensional free scalar O(N) vector model, and we compute the tree-level three-point Witten diagram amplitudes for a generic cubic interaction of higher spin gauge fields in the metriclike formulation. PMID:27203314
Higher Spin Interactions from Conformal Field Theory: The Complete Cubic Couplings
NASA Astrophysics Data System (ADS)
Sleight, Charlotte; Taronna, Massimo
2016-05-01
In this Letter we provide a complete holographic reconstruction of the cubic couplings in the minimal bosonic higher spin theory in (d +1 )-dimensional anti- de Sitter space. For this purpose, we also determine the operator-product expansion coefficients of all single-trace conserved currents in the d -dimensional free scalar O (N ) vector model, and we compute the tree-level three-point Witten diagram amplitudes for a generic cubic interaction of higher spin gauge fields in the metriclike formulation.
NASA Astrophysics Data System (ADS)
Momose, Takamasa; Yamaguchi, Makoto; Shida, Tadamasa
1990-11-01
Following the previous work on the isotropic hyperfine coupling constants (HFCCs) of polyatomic radicals the symmetry adapted cluster expansion-configuration interaction (SAC-CI) theory is applied to calculate anisotropic HFCCs also. The results are compared with available experimental data from diatomic to polyatomic radicals such as the vinoxy. For radicals consisting of only the first row atoms Dunning's double zeta (DZ) basis set is shown to be adequate, but for those containing the second row atoms inclusion of polarization functions is required. Compared with the isotropic HFCC the calculation of the anisotropic HFCC is less formidable. However, ignorance of electron correlation causes serious disagreements with experimental data.
Technology Transfer Automated Retrieval System (TEKTRAN)
A simple analytical method using hydrophilic interaction liquid chromatography coupled with mass spectrometry was developed to screen for low molecular weight compounds in enzyme treated and untreated Alaskan pollock (Theragra chalcogramma) stickwater (SW) generated from processing fish meal with po...
Beyond the rainbow: Effects from pion back-coupling
Fischer, Christian S.; Williams, Richard
2008-10-01
We investigate hadronic unquenching effects in light quarks and mesons. To this end, we take into account the back-coupling of the pion onto the quark propagator within the nonperturbative continuum framework of Schwinger-Dyson equations (SDE) and Bethe-Salpeter equations (BSE). We improve on a previous approach by explicitly solving both the coupled system of SDEs and BSEs in the complex plane and the normalization problem for Bethe-Salpeter kernels depending on the total momentum of the meson. As a result of our study, we find considerable unquenching effects in the spectrum of light pseudoscalar, vector and axial-vector mesons.
Astolfi, L; Toppi, J; Borghini, G; Vecchiato, G; He, E J; Roy, A; Cincotti, F; Salinari, S; Mattia, D; He, B; Babiloni, F
2012-01-01
Controlling an aircraft during a flight is a compelling condition, which requires a strict and well coded interaction between the crew. The interaction level between the Captain and the First Officer changes during the flight, ranging from a maximum (during takeoff and landing, as well as in case of a failure of the instrumentation or other emergency situations) to a minimum during quiet mid-flight. In this study, our aim is to investigate the neural correlates of different kinds and levels of interaction between couples of professional crew members by means of the innovative technique called brain hyperscanning, i.e. the simultaneous recording of the hemodynamic or neuroelectrical activity of different human subjects involved in interaction tasks. This approach allows the observation and modeling of the neural signature specifically dependent on the interaction between subjects, and, even more interestingly, of the functional links existing between the brain activities of the subjects interacting together. In this EEG hyperscanning study, different phases of a flight were reproduced in a professional flight simulator, which allowed, on one side, to reproduce the ecological setting of a real flight, and, on the other, to keep under control the different levels of interaction induced in the crew by means of systematic and simulated failures of the aircraft instrumentation. Results of the procedure of linear inverse estimation, together with functional hyperconnectivity estimated by means of Partial Directed Coherence, showed a dense network of connections between the activity in the two brains in the takeoff and landing phases, when the cooperation between the crew is maximal, while conversely no significant links were shown during the phases in which the activity of the two pilots was independent.
Disentangling running coupling and conformal effects in QCD
Brodsky, S. J.; Gardi, E.; Grunberg, G.; Rathsman, J.
2001-05-01
We investigate the relation between a postulated skeleton expansion and the conformal limit of QCD. We begin by developing some consequences of an Abelian-like skeleton expansion, which allows one to disentangle running-coupling effects from the remaining skeleton coefficients. The latter are by construction renormalon free, and hence hopefully better behaved. We consider a simple ansatz for the expansion, where an observable is written as a sum of integrals over the running coupling. We show that in this framework one can set a unique Brodsky-Lepage-Mackenzie (BLM) scale-setting procedure as an approximation to the running-coupling integrals, where the BLM coefficients coincide with the skeleton ones. Alternatively, the running-coupling integrals can be approximated using the effective charge method. We discuss the limitations in disentangling running coupling effects in the absence of a diagrammatic construction of the skeleton expansion. Independently of the assumed skeleton structure we show that BLM coefficients coincide with conformal coefficients defined in the small {beta}{sub 0} (Banks-Zaks) limit where a perturbative infrared fixed point is present. This interpretation of the BLM coefficients should explain their previously observed simplicity and smallness. Numerical examples are critically discussed.
Solares, Santiago D
2016-01-01
Significant progress has been accomplished in the development of experimental contact-mode and dynamic-mode atomic force microscopy (AFM) methods designed to measure surface material properties. However, current methods are based on one-dimensional (1D) descriptions of the tip-sample interaction forces, thus neglecting the intricacies involved in the material behavior of complex samples (such as soft viscoelastic materials) as well as the differences in material response between the surface and the bulk. In order to begin to address this gap, a computational study is presented where the sample is simulated using an enhanced version of a recently introduced model that treats the surface as a collection of standard-linear-solid viscoelastic elements. The enhanced model introduces in-plane surface elastic forces that can be approximately related to a two-dimensional (2D) Young's modulus. Relevant cases are discussed for single- and multifrequency intermittent-contact AFM imaging, with focus on the calculated surface indentation profiles and tip-sample interaction force curves, as well as their implications with regards to experimental interpretation. A variety of phenomena are examined in detail, which highlight the need for further development of more physically accurate sample models that are specifically designed for AFM simulation. A multifrequency AFM simulation tool based on the above sample model is provided as supporting information. PMID:27335746
Solares, Santiago D.
2016-04-15
Significant progress has been accomplished in the development of experimental contact-mode and dynamic-mode atomic force microscopy (AFM) methods designed to measure surface material properties. However, current methods are based on one-dimensional (1D) descriptions of the tip-sample interaction forces, thus neglecting the intricacies involved in the material behavior of complex samples (such as soft viscoelastic materials) as well as the differences in material response between the surface and the bulk. In order to begin to address this gap, a computational study is presented where the sample is simulated using an enhanced version of a recently introduced model that treats the surfacemore » as a collection of standard-linear-solid viscoelastic elements. The enhanced model introduces in-plane surface elastic forces that can be approximately related to a two-dimensional (2D) Young's modulus. Relevant cases are discussed for single-and multifrequency intermittent-contact AFM imaging, with focus on the calculated surface indentation profiles and tip-sample interaction force curves, as well as their implications with regards to experimental interpretation. A variety of phenomena are examined in detail, which highlight the need for further development of more physically accurate sample models that are specifically designed for AFM simulation. As a result, a multifrequency AFM simulation tool based on the above sample model is provided as supporting information.« less
Solares, Santiago D
2016-01-01
Significant progress has been accomplished in the development of experimental contact-mode and dynamic-mode atomic force microscopy (AFM) methods designed to measure surface material properties. However, current methods are based on one-dimensional (1D) descriptions of the tip-sample interaction forces, thus neglecting the intricacies involved in the material behavior of complex samples (such as soft viscoelastic materials) as well as the differences in material response between the surface and the bulk. In order to begin to address this gap, a computational study is presented where the sample is simulated using an enhanced version of a recently introduced model that treats the surface as a collection of standard-linear-solid viscoelastic elements. The enhanced model introduces in-plane surface elastic forces that can be approximately related to a two-dimensional (2D) Young's modulus. Relevant cases are discussed for single- and multifrequency intermittent-contact AFM imaging, with focus on the calculated surface indentation profiles and tip-sample interaction force curves, as well as their implications with regards to experimental interpretation. A variety of phenomena are examined in detail, which highlight the need for further development of more physically accurate sample models that are specifically designed for AFM simulation. A multifrequency AFM simulation tool based on the above sample model is provided as supporting information.
2016-01-01
Summary Significant progress has been accomplished in the development of experimental contact-mode and dynamic-mode atomic force microscopy (AFM) methods designed to measure surface material properties. However, current methods are based on one-dimensional (1D) descriptions of the tip–sample interaction forces, thus neglecting the intricacies involved in the material behavior of complex samples (such as soft viscoelastic materials) as well as the differences in material response between the surface and the bulk. In order to begin to address this gap, a computational study is presented where the sample is simulated using an enhanced version of a recently introduced model that treats the surface as a collection of standard-linear-solid viscoelastic elements. The enhanced model introduces in-plane surface elastic forces that can be approximately related to a two-dimensional (2D) Young’s modulus. Relevant cases are discussed for single- and multifrequency intermittent-contact AFM imaging, with focus on the calculated surface indentation profiles and tip–sample interaction force curves, as well as their implications with regards to experimental interpretation. A variety of phenomena are examined in detail, which highlight the need for further development of more physically accurate sample models that are specifically designed for AFM simulation. A multifrequency AFM simulation tool based on the above sample model is provided as supporting information. PMID:27335746
Tunable terahertz half-wave plate based on hybridization effect in coupled graphene nanodisks
NASA Astrophysics Data System (ADS)
Peng, Jialong; Zhu, Zhihong; Zhang, Jianfa; Yuan, Xiaodong; Qin, Shiqiao
2016-05-01
We demonstrate a tunable terahertz half-wave plate composed of a periodic array of graphene nanodisk dimers supported on a dielectric spacer backed by a planar gold layer. The polarization conversion phenomena are attributed to the hybridization effect caused by coupling interactions between plasmonic resonances in the graphene nanodisk dimers. By varying the distance between graphene nanodisks, the polarization conversion performance can be controlled. Further, the polarization conversion can be dynamically tuned at different frequencies via electrostatic doping of graphene. Other novel phenomena and applications could be developed from coupled graphene structures in the future.
Weakly interacting spinor Bose-Einstein condensates with three-dimensional spin-orbit coupling
NASA Astrophysics Data System (ADS)
Shu-Wei, Song; Rui, Sun; Hong, Zhao; Xuan, Wang; Bao-Zhong, Han
2016-04-01
Starting from the Hamiltonian of the second quantization form, the weakly interacting Bose-Einstein condensate with spin-orbit coupling of Weyl type is investigated. It is found that the SU(2) nonsymmetric term, i.e., the spin-dependent interaction, can lift the degeneracy of the ground states with respect to the z component of the total angular momentum J z , casting the ground condensate state into a configuration of zero J z . This ground state density profile can also be affirmed by minimizing the full Gross-Pitaevskii energy functional. The spin texture of the zero J z state indicates that it is a knot structure, whose fundamental group is π 3(M) ≅ π 3(S 2) = Z. Project supported by the National Natural Science Foundation of China (Grant No. 11447178).
NASA Astrophysics Data System (ADS)
Chang, Ying-Feng; Hsieh, Jo-Ping; Su, Li-Chen; Li, Ying-Chang; Lee, Cheng-Chung; Chou, Chien
2010-08-01
In this study, we describe a novel method for analyzing protein-protein binding kinetics at ultra-low concentration (1 pg/mL) using a localized surface plasmon coupled fluorescence fiber-optic biosensor (LSPCF-FOB). The association and dissociation rate constants, ka and kd, respectively, for the binding kinetics of the mouse IgG/ anti-mouse IgG interaction have been calculated to be ka = (5.9928+/-3.1540)x106 M-1s-1 and kd = (1.0587+/-0.5572)x10-3 s-1. The theoretical basis of this analytical approach is a rapid-mixing model integrated with a two-compartment model; has been experimentally verified in this study as well. The LSPCF-FOB provides a potentially alternative option for characterizing the interaction of biomolecules at ultra-low concentrations.
Effect of mixed coupling on relay-coupled Rössler and Lorenz oscillators.
Sharma, Amit; Shrimali, Manish Dev; Aihara, K
2014-12-01
The complete synchronization between the outermost oscillators using the mixed coupling in relay coupled systems is studied. Mixed coupling has two types of coupling functions: coupling between similar or dissimilar variables. We examine the complete synchronization in relay-coupled systems by the largest transverse Lyapunov exponent and synchronization error. We show numerically for Rössler and Lorenz oscillators that the combination of these two types of coupling functions is able to decrease the critical coupling strength for complete synchronization as well as it also suppress oscillations for larger coupling strength.
Köhn, Andreas; Olsen, Jeppe
2005-02-22
It is shown that due to the mixing of the usual projection approach of coupled cluster with variational orbital optimization, orbital-optimized coupled cluster (OCC) fails to reproduce the full configuration-interaction (full CI) limit when the cluster operator becomes complete. It is pointed out that the fulfillment of the projected singles equations, which define the orbital gradient in Brueckner coupled cluster (BCC), is mandatory for a correct behavior. As numerical examples we present general OCC and BCC calculations up to the full CI limit on CH(2) and an active-space model of ozone. The observed deviations of OCC from full CI are of the order of the correlation error obtained in calculations with up to quadruples excitations. Thus the failure of OCC may be considered tolerable in more approximate calculations but clearly prohibitive for any benchmark application. For applications to active-space models a hybrid approach for OCC is suggested in which for active particle-hole rotations the Brueckner orbital gradient is employed, whereas for the remaining orbital rotations the variational orbital gradient is retained. PMID:15836029
Standing wave plasmon modes interact in an antenna-coupled nanowire
NASA Astrophysics Data System (ADS)
Day, Jared; Large, Nicolas; Nordlander, Peter; Halas, Naomi
2015-03-01
In a standing wave optical cavity, the coupling of cavity modes, e.g. through a nonlinear medium, results in a rich variety of nonlinear dynamical phenomena, such as frequency pushing and pulling, mode-locking and pulsing, and modal instabilities. Metallic nanowires of finite length support a hierarchy of longitudinal surface plasmon modes with standing wave properties: the plasmonic analog of a Fabry-Pérot cavity. Here we show that positioning the nanowire within the gap of a plasmonic nanoantenna introduces a passive, hybridization-based coupling of the standing-wave nanowire plasmon modes with the antenna structure, mediating an interaction between the nanowire plasmon modes themselves. Frequency pushing and pulling, and the enhancement and suppression of specific plasmon modes, can be controlled and manipulated by nanoantenna position and shape. Dark-field spectroscopy, CL spectroscopy and imaging, and finite-difference time-domain calculations are performed to investigate these surface plasmon ``drift.'' Near-field coupling of nanoantennas to nanowire optical cavities shows that plasmon hybridization is a powerful strategy for controlling the radiative LDOS of nanowires, and could ultimately enable strategies for active control of emission properties in nanowire-based devices. Work funded by the Welch Foundation (C-1220, C-1222), the NSSEFF (N00244-09-1-0067), the ONR (N00014-10-1-0989), and the NSF (ECCS-1040478, CNS-0821727).
GGA3 Interacts with a G Protein-Coupled Receptor and Modulates Its Cell Surface Export
Zhang, Maoxiang; Davis, Jason E.; Li, Chunman; Gao, Jie; Huang, Wei; Lambert, Nevin A.; Terry, Alvin V.
2016-01-01
Molecular mechanisms governing the anterograde trafficking of nascent G protein-coupled receptors (GPCRs) are poorly understood. Here, we have studied the regulation of cell surface transport of α2-adrenergic receptors (α2-ARs) by GGA3 (Golgi-localized, γ-adaptin ear domain homology, ADP ribosylation factor-binding protein 3), a multidomain clathrin adaptor protein that sorts cargo proteins at the trans-Golgi network (TGN) to the endosome/lysosome pathway. By using an inducible system, we demonstrated that GGA3 knockdown significantly inhibited the cell surface expression of newly synthesized α2B-AR without altering overall receptor synthesis and internalization. The receptors were arrested in the TGN. Furthermore, GGA3 knockdown attenuated α2B-AR-mediated signaling, including extracellular signal-regulated kinase 1/2 (ERK1/2) activation and cyclic AMP (cAMP) inhibition. More interestingly, GGA3 physically interacted with α2B-AR, and the interaction sites were identified as the triple Arg motif in the third intracellular loop of the receptor and the acidic motif EDWE in the VHS domain of GGA3. In contrast, α2A-AR did not interact with GGA3 and its cell surface export and signaling were not affected by GGA3 knockdown. These data reveal a novel function of GGA3 in export trafficking of a GPCR that is mediated via a specific interaction with the receptor. PMID:26811329
Mekler, Vladimir; Minakhin, Leonid; Borukhov, Sergei; Mustaev, Arkady; Severinov, Konstantin
2014-01-01
Bacterial RNA polymerase (RNAP) makes extensive contacts with duplex DNA downstream of the transcription bubble in initiation and elongation complexes. We investigated the role of downstream interactions in formation of catalytically competent transcription initiation complex by measuring initiation activity of stable RNAP complexes with model promoter DNA fragments whose downstream ends extend from +3 to +21 relative to the transcription start site at +1. We found that DNA downstream of position +6 does not play a significant role in transcription initiation when RNAP-promoter interactions upstream of the transcription start site are strong and promoter melting region is AT-rich. Further shortening of downstream DNA dramatically reduces efficiency of transcription initiation. The boundary of minimal downstream DNA duplex needed for efficient transcription initiation shifted further away from the catalytic center upon increasing the GC content of promoter melting region or in the presence of bacterial stringent response regulators DksA and ppGpp. These results indicate that the strength of RNAP-downstream DNA interactions has to reach a certain threshold to retain the catalytically competent conformation of the initiation complex and that establishment of contacts between RNAP and downstream DNA can be coupled with promoter melting. The data further suggest that RNAP interactions with DNA immediately downstream of the transcription bubble are particularly important for initiation of transcription. We hypothesize that these active center-proximal contacts stabilize the DNA template strand in the active center cleft and/or position the RNAP clamp domain to allow RNA synthesis. PMID:25311862
NASA Astrophysics Data System (ADS)
Zhong, Xiao; Sun, Peide; Song, Yingqi; Wang, Ruyi; Fang, Zhiguo
2010-11-01
Based on the fully coupled activated sludge model (FCASM), the novel model Tubificidae -Fully Coupled Activated Sludge Model-hydraulic (T-FCASM-Hydro), has been developed in our previous work. T-FCASM-Hydro not only describe the interactive system between Tubificidae and functional microorganisms for the sludge reduction and nutrient removal simultaneously, but also considere the interaction between biological and hydraulic field, After calibration and validation of T-FCASM-Hydro at Zhuji Feida-hongyu Wastewater treatment plant (WWTP) in Zhejiang province, T-FCASM-Hydro was applied for determining optimal operating condition in the WWTP. Simulation results showed that nitrogen and phosphorus could be removed efficiently, and the efficiency of NH4+-N removal enhanced with increase of DO concentration. At a certain low level of DO concentration in the aerobic stage, shortcut nitrification-denitrification dominated in the process of denitrification in the novel system. However, overhigh agitation (>6 mgṡL-1) could result in the unfavorable feeding behavior of Tubificidae because of the strong flow disturbance, which might lead to low rate of sludge reduction. High sludge reduction rate and high removal rate of nitrogen and phosphorus could be obtained in the new-style oxidation ditch when DO concentration at the aerobic stage with Tubificidae was maintained at 3.6 gṡm-3.
Extracting Effective Higgs Couplings in the Golden Channel
Chen, Yi; Vega-Morales, Roberto
2014-04-08
Kinematic distributions in Higgs decays to four charged leptons, the so called ‘golden channel, are a powerful probe of the tensor structure of its couplings to neutral electroweak gauge bosons. In this study we construct the first part of a comprehensive analysis framework designed to maximize the information contained in this channel in order to perform direct extraction of the various possible Higgs couplings. We first complete an earlier analytic calculation of the leading order fully differential cross sections for the golden channel signal and background to include the 4e and 4μ final states with interference between identical final states. We also examine the relative fractions of the different possible combinations of scalar-tensor couplings by integrating the fully differential cross section over all kinematic variables as well as show various doubly differential spectra for both the signal and background. From these analytic expressions we then construct a ‘generator level’ analysis framework based on the maximum likelihood method. Then, we demonstrate the ability of our framework to perform multi-parameter extractions of all the possible effective couplings of a spin-0 scalar to pairs of neutral electroweak gauge bosons including any correlations. Furthermore, this framework provides a powerful method for study of these couplings and can be readily adapted to include the relevant detector and systematic effects which we demonstrate in an accompanying study to follow.
Trilinear neutral gauge boson couplings in effective theories
NASA Astrophysics Data System (ADS)
Larios, F.; Pérez, M. A.; Tavares-Velasco, G.; Toscano, J. J.
2001-06-01
We list all the lowest dimension effective operators inducing off-shell trilinear neutral gauge boson couplings ZZγ, Zγγ, and ZZZ within the effective Lagrangian approach, both in the linear and nonlinear realizations of SU(2)L × U(1)Y gauge symmetry. In the linear scenario we find that these couplings can be generated only by dimension-8 operators necessarily including the Higgs boson field, whereas in the nonlinear case they are induced by dimension-6 operators. We consider the impact of these couplings on some precision measurements such as the magnetic and electric dipole moments of fermions, as well as the Z boson rare decay Z-->νν¯γ. If the underlying new physics is of a decoupling nature, it is not expected that trilinear neutral gauge boson couplings may affect considerably any of these observables. On the contrary, it is just in the nonlinear scenario where these couplings have the more promising prospects of being perceptible through high precision experiments.
Extracting Effective Higgs Couplings in the Golden Channel
Chen, Yi; Vega-Morales, Roberto
2014-04-08
Kinematic distributions in Higgs decays to four charged leptons, the so called ‘golden channel, are a powerful probe of the tensor structure of its couplings to neutral electroweak gauge bosons. In this study we construct the first part of a comprehensive analysis framework designed to maximize the information contained in this channel in order to perform direct extraction of the various possible Higgs couplings. We first complete an earlier analytic calculation of the leading order fully differential cross sections for the golden channel signal and background to include the 4e and 4μ final states with interference between identical final states.more » We also examine the relative fractions of the different possible combinations of scalar-tensor couplings by integrating the fully differential cross section over all kinematic variables as well as show various doubly differential spectra for both the signal and background. From these analytic expressions we then construct a ‘generator level’ analysis framework based on the maximum likelihood method. Then, we demonstrate the ability of our framework to perform multi-parameter extractions of all the possible effective couplings of a spin-0 scalar to pairs of neutral electroweak gauge bosons including any correlations. Furthermore, this framework provides a powerful method for study of these couplings and can be readily adapted to include the relevant detector and systematic effects which we demonstrate in an accompanying study to follow.« less
Coupled-oscillator theory of dispersion and Casimir-Polder interactions
Berman, P. R.; Ford, G. W.; Milonni, P. W.
2014-10-28
We address the question of the applicability of the argument theorem (of complex variable theory) to the calculation of two distinct energies: (i) the first-order dispersion interaction energy of two separated oscillators, when one of the oscillators is excited initially and (ii) the Casimir-Polder interaction of a ground-state quantum oscillator near a perfectly conducting plane. We show that the argument theorem can be used to obtain the generally accepted equation for the first-order dispersion interaction energy, which is oscillatory and varies as the inverse power of the separation r of the oscillators for separations much greater than an optical wavelength. However, for such separations, the interaction energy cannot be transformed into an integral over the positive imaginary axis. If the argument theorem is used incorrectly to relate the interaction energy to an integral over the positive imaginary axis, the interaction energy is non-oscillatory and varies as r{sup −4}, a result found by several authors. Rather remarkably, this incorrect expression for the dispersion energy actually corresponds to the nonperturbative Casimir-Polder energy for a ground-state quantum oscillator near a perfectly conducting wall, as we show using the so-called “remarkable formula” for the free energy of an oscillator coupled to a heat bath [G. W. Ford, J. T. Lewis, and R. F. O’Connell, Phys. Rev. Lett. 55, 2273 (1985)]. A derivation of that formula from basic results of statistical mechanics and the independent oscillator model of a heat bath is presented.
PIP2-dependent coupling is prominent in Kv7.1 due to weakened interactions between S4-S5 and S6
NASA Astrophysics Data System (ADS)
Kasimova, Marina A.; Zaydman, Mark A.; Cui, Jianmin; Tarek, Mounir
2015-01-01
Among critical aspects of voltage-gated potassium (Kv) channels' functioning is the effective communication between their two composing domains, the voltage sensor (VSD) and the pore. This communication, called coupling, might be transmitted directly through interactions between these domains and, as recently proposed, indirectly through interactions with phosphatidylinositol-4,5-bisphosphate (PIP2), a minor lipid of the inner plasma membrane leaflet. Here, we show how the two components of coupling, mediated by protein-protein or protein-lipid interactions, both contribute in the Kv7.1 functioning. On the one hand, using molecular dynamics simulations, we identified a Kv7.1 PIP2 binding site that involves residues playing a key role in PIP2-dependent coupling. On the other hand, combined theoretical and experimental approaches have shown that the direct interaction between the segments of the VSD (S4-S5) and the pore (S6) is weakened by electrostatic repulsion. Finally, we conclude that due to weakened protein-protein interactions, the PIP2-dependent coupling is especially prominent in Kv7.1.
PIP₂-dependent coupling is prominent in Kv7.1 due to weakened interactions between S4-S5 and S6.
Kasimova, Marina A; Zaydman, Mark A; Cui, Jianmin; Tarek, Mounir
2015-01-06
Among critical aspects of voltage-gated potassium (Kv) channels' functioning is the effective communication between their two composing domains, the voltage sensor (VSD) and the pore. This communication, called coupling, might be transmitted directly through interactions between these domains and, as recently proposed, indirectly through interactions with phosphatidylinositol-4,5-bisphosphate (PIP₂), a minor lipid of the inner plasma membrane leaflet. Here, we show how the two components of coupling, mediated by protein-protein or protein-lipid interactions, both contribute in the Kv7.1 functioning. On the one hand, using molecular dynamics simulations, we identified a Kv7.1 PIP₂ binding site that involves residues playing a key role in PIP₂-dependent coupling. On the other hand, combined theoretical and experimental approaches have shown that the direct interaction between the segments of the VSD (S4-S5) and the pore (S6) is weakened by electrostatic repulsion. Finally, we conclude that due to weakened protein-protein interactions, the PIP2-dependent coupling is especially prominent in Kv7.1.
Effective gravitational couplings for cosmological perturbations in generalized Proca theories
NASA Astrophysics Data System (ADS)
De Felice, Antonio; Heisenberg, Lavinia; Kase, Ryotaro; Mukohyama, Shinji; Tsujikawa, Shinji; Zhang, Ying-li
2016-08-01
We consider the finite interactions of the generalized Proca theory including the sixth-order Lagrangian and derive the full linear perturbation equations of motion on the flat Friedmann-Lemaître-Robertson-Walker background in the presence of a matter perfect fluid. By construction, the propagating degrees of freedom (besides the matter perfect fluid) are two transverse vector perturbations, one longitudinal scalar, and two tensor polarizations. The Lagrangians associated with intrinsic vector modes neither affect the background equations of motion nor the second-order action of tensor perturbations, but they do give rise to nontrivial modifications to the no-ghost condition of vector perturbations and to the propagation speeds of vector and scalar perturbations. We derive the effective gravitational coupling Geff with matter density perturbations under a quasistatic approximation on scales deep inside the sound horizon. We find that the existence of intrinsic vector modes allows a possibility for reducing Geff. In fact, within the parameter space, Geff can be even smaller than the Newton gravitational constant G at the late cosmological epoch, with a peculiar phantom dark energy equation of state (without ghosts). The modifications to the slip parameter η and the evolution of the growth rate f σ8 are discussed as well. Thus, dark energy models in the framework of generalized Proca theories can be observationally distinguished from the Λ CDM model according to both cosmic growth and expansion history. Furthermore, we study the evolution of vector perturbations and show that outside the vector sound horizon the perturbations are nearly frozen and start to decay with oscillations after the horizon entry.
Tropical Cyclones-Ocean Interactions in a High Resolution GCM: the Role of the Coupling Frequency
NASA Astrophysics Data System (ADS)
Scoccimarro, E.; Fogli, P. G.; Masina, S.; Gualdi, S.; Navarra, A.
2015-12-01
The interaction between Tropical Cyclones (TCs) and ocean is a major mechanism responsible for energy exchange between the atmosphere and the ocean. TCs affect the thermal and dynamical structure of the ocean, but the magnitude of the impact is still uncertain. Very few CMIP5 models demonstrated ability in representing TCs, mainly due to their horizontal resolution. We aim to improve TCs representation in next CMIPs experiments through the new CMCC-CESM-NEMO General Circulation Model, having a horizontal resolution of ¼ degree in both atmospheric and ocean components. The model is capable to represent realistically TCs up to Cat-4 Typhoons. The wind structure associated with TCs is responsible for two important atmosphere-ocean feedbacks: the first feedback — positive — is driven by the latent heat associated with the enhanced evaporation rate and leads to an increase of the available energy for TC. The second feedback — negative — is due to the cold water upwelling induced by the increased wind stress at the ocean surface and by the shear-induced mixing at the base of the mixed layer. The second feedback is responsible for a significant cooling of the sea surface, leading to a weakening of the cyclone intensity due to the reduction of the total heat flux into the atmosphere. Furthermore TC intensification, intensity, and lifetime strongly depend on their transitional speed. A good representation of the TC-Ocean interaction strongly depends on the coupling frequency between the atmospheric and the ocean components, especially when simulating fast moving TCs. In this work, we investigate the role of the coupling frequency in representing the two mentioned feedbacks using the new fully coupled General Circulation Model developed at CMCC.
Plasma interactions and surface/material effects
NASA Technical Reports Server (NTRS)
Mandel, M.; Chutjian, A.; Hall, W.; Leung, P.; Robinson, P.; Stevens, N. J.
1986-01-01
A discussion on plasma interactions and surface/material effects is summarized. The key issues in this area were: (1) the lack of data on the material properties of common spacecraft surface materials; (2) lack of understanding of the contamination and decontamination processes; and (3) insufficient analytical tools to model synergistic phenomena related to plasma interactions. Without an adequate database of material properties, accurate system performance predictions cannot be made. The interdisciplinary nature of the surface-plasma interactions area makes it difficult to plan and maintain a coherent theoretical and experimental program. The shuttle glow phenomenon is an excellent example of an unanticipated, complex interaction involving synergism between surface and plasma effects. Building an adequate technology base for understanding and predicting surface-plasma interactions will require the coordinated efforts of engineers, chemists, and physicists. An interdisciplinary R and D program should be organized to deal with similar problems that the space systems of the 21st century may encounter.
Plasma interactions and surface/material effects
NASA Astrophysics Data System (ADS)
Mandel, M.; Chutjian, A.; Hall, W.; Leung, P.; Robinson, P.; Stevens, N. J.
1986-10-01
A discussion on plasma interactions and surface/material effects is summarized. The key issues in this area were: (1) the lack of data on the material properties of common spacecraft surface materials; (2) lack of understanding of the contamination and decontamination processes; and (3) insufficient analytical tools to model synergistic phenomena related to plasma interactions. Without an adequate database of material properties, accurate system performance predictions cannot be made. The interdisciplinary nature of the surface-plasma interactions area makes it difficult to plan and maintain a coherent theoretical and experimental program. The shuttle glow phenomenon is an excellent example of an unanticipated, complex interaction involving synergism between surface and plasma effects. Building an adequate technology base for understanding and predicting surface-plasma interactions will require the coordinated efforts of engineers, chemists, and physicists. An interdisciplinary R and D program should be organized to deal with similar problems that the space systems of the 21st century may encounter.
Constraining gravitational interactions in the M theory effective action
NASA Astrophysics Data System (ADS)
Basu, Anirban
2014-08-01
We consider purely gravitational interactions of the type {{D}^{6n}}{{{ R}}^{4}} in the effective action of M theory in 11 dimensional flat spacetime. The duality between M theory on S 1 and type IIA string theory relates them to the type IIA interactions of the form {{e}^{2n{{\\phi }_{A}}}}{{D}^{6n}}{{{ R}}^{4}} where {{\\phi }_{A}} is the type IIA dilaton. The coefficients of the M theory interactions are determined by the strongly coupled type IIA theory. Given the nature of the dilaton dependence, it is plausible that for low values of n, the coefficient has a similar structure as the genus (n+1) string amplitude of the type IIA {{D}^{6n}}{{{ R}}^{4}} interaction, namely the transcendental nature. Assuming this, and focussing on the even-even spin structure part of the type IIA string amplitude, this coefficient is given by the type IIB genus (n+1) amplitude, which we constrain using supersymmetry, S-duality and maximal supergravity. The source terms of the Poisson equations satisfied by the S-duality invariant IIB couplings play a central role in the analysis. This procedure yields partial contributions to several multi-loop type IIB string amplitudes, from which we extract the transcendental nature of the corresponding M theory couplings. For n\\leqslant 2, all possible source terms involve only BPS couplings. While the {{{ R}}^{4}} and {{D}^{6}}{{{ R}}^{4}} M theory couplings agree with known results, the coefficient of the {{D}^{12}}{{{ R}}^{4}} interaction takes the form \\zeta {{(2)}^{3}}({{\\Omega }_{1}}+{{\\Omega }_{2}}\\zeta (3)). We also analyze the {{D}^{18}}{{{ R}}^{4}} and {{D}^{24}}{{{ R}}^{4}} interactions, and show that their coefficients have at least the terms \\zeta {{(2)}^{4}}({{\\tilde{\\Omega }}_{1}}+{{\\tilde{\\Omega }}_{2}}\\zeta (3)+{{\\tilde{\\Omega }}_{3}}\\zeta (5)) and \\zeta {{(2)}^{5}}({{\\underline{\\Omega }}_{1}}+{{\\underline{\\Omega }}_{2}}\\zeta (3)+{{\\underline{\\Omega }}_{3}}\\zeta (5) +\\;{{\\underline{\\Omega }}_{4
Skin to skin interactions. Does the infant massage improve the couple functioning?
Gnazzo, Antonio; Guerriero, Viviana; Di Folco, Simona; Zavattini, Giulio C.; de Campora, Gaia
2015-01-01
Transition to parenthood is a critical stage of life due to several changes the couple has to handle. A large body of studies described how transition to parenthood can be linked to the onset of depressive symptoms, as well as the perception of a low social support, and an increased stress, representing a risk for the early mother–baby relationship. Infant massage (IM) emerged as a helpful tool to improve maternal skills in interacting with the baby, and leading toward a decreasing of post-partum symptoms. However, a growing body of literature highlights that men also may experience post-partum diseases, representing an additional risk for the development of the baby. To date, no study observed the impact of the IM on both partners. The aim of the current qualitative research is to observe the impact of the IM on a single couple of parents at childbirth. Pre (Time 1) and post-intervention (Time 3) procedure has been established to observe the changes occurring over the time in the couple. In particular, each member of the couple filled out the EPDS, the BDI-II, the MSPSS, and the PSI-SF both at Time 1 and at Time 3. The treatment (Time 2) was represented by the IM training, and lasted 4 weeks. Findings revealed a decrease in depressive symptoms in both partners, as well as an improvement of their perception of stress related to parental role. No changes has been detected with respect to the perception of social support. The IM seems to be a helpful approach to prevent the establishment of pathological conditions in new parents. Although no direct measures on the child were used, the current qualitative data seem to suggest that the IM may represent a valuable tool to prevent the onset of early negative outcomes of the baby. Further investigations and empirical data are needed to improve the knowledge in this field. PMID:26441813
The Casual Effects of Emotion on Couples' Cognition and Behavior
ERIC Educational Resources Information Center
Tashiro, Ty; Frazier, Patricia
2007-01-01
The authors conducted 2 translational studies that assessed the causal effects of emotion on maladaptive cognitions and behaviors in couples. Specifically, the authors examined whether negative emotions increased and positive emotions decreased partner attributions and demand-withdraw behaviors. Study 1 (N=164) used video clips to assess the…
Effects of ionizing radiation on charge-coupled imagers
NASA Technical Reports Server (NTRS)
Killiany, J. M.; Baker, W. D.; Saks, N. S.; Barbe, D. F.
1975-01-01
The effects of ionizing radiation on three different charge coupled imagers have been investigated. Device performance was evaluated as a function of total gamma ray dose. The principal failure mechanisms have been identified for each particular device structure. The clock and bias voltages required for high total dose operation of the devices are presented.
Visco-elastic effects in strongly coupled dusty plasmas
Bandyopadhyay, P.; Prasad, G.; Sen, A.; Kaw, P. K.
2008-09-07
We report on experimental evidence of visco-elastic effects in a strongly coupled dusty plasma through investigations of the propagation characteristics of low frequency dust acoustic waves and by excitations of transverse shear waves in a DC discharge Argon plasma.
Impurity effects on coupled quantum dot spin qubits in semiconductors
NASA Astrophysics Data System (ADS)
Nguyen, Nga; Das Sarma, Sankar
2011-03-01
Localized electron spins confined in semiconductor quantum dots are being studied by many groups as possible elementary qubits for solid-state quantum computation. We theoretically consider the effects of having unintentional charged impurities in laterally coupled two-dimensional double (GaAs) quantum dot systems, where each dot contains one or two electrons and a single charged impurity in the presence of an external magnetic field. We calculate the effect of the impurity on the 2-electron energy spectrum of each individual dot as well as on the spectrum of the coupled-double-dot 2-electron system. We find that the singlet-triplet exchange splitting between the two lowest energy states, both for the individual dots and the coupled dot system, depends sensitively on the location of the impurity and its coupling strength (i.e. the effective charge). We comment on the impurity effect in spin qubit operations in the double dot system based on our numerical results. This work is supported by LPS-CMTC and CNAM.
NASA Astrophysics Data System (ADS)
Cotner, Eric
2016-09-01
Scalar particles are a common prediction of many beyond the Standard Model theories. If they are light and cold enough, there is a possibility they may form Bose-Einstein condensates, which will then become gravitationally bound. These boson stars are solitonic solutions to the Einstein-Klein-Gordon equations but may be approximated in the nonrelativistic regime with a coupled Schrödinger-Poisson system. General properties of single soliton states are derived, including the possibility of quartic self-interactions. Binary collisions between two solitons are then studied, and the effects of different mass ratios, relative phases, self-couplings, and separation distances are characterized, leading to an easy conceptual understanding of how these parameters affect the collision outcome in terms of conservation of energy. Applications to dark matter are discussed.
NASA Astrophysics Data System (ADS)
Bezerra, V. B.; Klimchitskaya, G. L.; Mostepanenko, V. M.; Romero, C.
2016-08-01
We propose an experiment for measuring the effective Casimir pressure between two parallel silicon carbide (SiC) plates with aligned nuclear spins. The prospective constraints on an axion-neutron coupling constant for both hadronic and grand unified theory (GUT) axions are calculated using the process of one-axion exchange. For this purpose, a general expression for the additional pressure arising between two polarized plates due to the exchange of one axion between their constituent fermions is derived. We demonstrate that only the polarization component perpendicular to the plates contributes to the pressure. The obtained pressure can be both repulsive and attractive depending on whether the polarizations of both plates are unidirectional or directed in opposite directions. It is shown that although the constraints on an axion-electron coupling obtained in the case of magnetized plates are not competitive, the constraints on an axion-neutron coupling found for plates with polarized nuclear spins are of the same order of magnitude as those obtained previously for the GUT axions alone using the process of two-axion exchange. The proposed experiment allows us also to strengthen the presently known constraints on the axion-neutron coupling constants of GUT axions by using both processes of one- and two-axion exchange.
Zhu, Bangjie; Liu, Feng; Li, Xituo; Wang, Yan; Gu, Xue; Dai, Jieyu; Wang, Guiming; Cheng, Yu; Yan, Chao
2015-01-01
Endogenous carbohydrates in biosamples are frequently highlighted as the most differential metabolites in many metabolomics studies. A simple, fast, simultaneous quantitative method for 16 endogenous carbohydrates in plasma has been developed using hydrophilic interaction liquid chromatography coupled with tandem mass spectrometry. In order to quantify 16 endogenous carbohydrates in plasma, various conditions, including columns, chromatographic conditions, mass spectrometry conditions, and plasma preparation methods, were investigated. Different conditions in this quantified analysis were performed and optimized. The reproducibility, precision, recovery, matrix effect, and stability of the method were verified. The results indicated that a methanol/acetonitrile (50:50, v/v) mixture could effectively and reproducibly precipitate rat plasma proteins. Cold organic solvents coupled with vortex for 1 min and incubated at -20°C for 20 min were the most optimal conditions for protein precipitation and extraction. The results, according to the linearity, recovery, precision, matrix effect, and stability, showed that the method was satisfactory in the quantification of endogenous carbohydrates in rat plasma. The quantified analysis of endogenous carbohydrates in rat plasma performed excellently in terms of sensitivity, high throughput, and simple sample preparation, which met the requirement of quantification in specific expanded metabolomic studies after the global metabolic profiling research.
NASA Astrophysics Data System (ADS)
Gong, W.; Makar, P. A.; Zhang, J.; Milbrandt, J.; Gravel, S.; Hayden, K. L.; Macdonald, A. M.; Leaitch, W. R.
2015-08-01
A fully coupled on-line air quality forecast model, GEM-MACH, was used to study aerosol-cloud interactions for a case of an urban-industrial plume impacting stratocumulus. The aerosol effect on the cloud microphysics was achieved by the use of parameterization of cloud droplet nucleation predicted from the on-line size- and composition-resolved aerosols and coupled with a double-moment cloud microphysics parameterization. The model simulations with and without the on-line aerosol effect on cloud microphysics were compared and evaluated against in-situ aerosol and cloud observations from ICARTT 2004. Inclusion of the on-line aerosol interaction with cloud resulted in an increase in modelled cloud amount and cloud liquid water content (LWC) due to increased cloud droplet number concentration (Nd), a decrease in cloud droplet size and a reduction in warm precipitation. The modelled LWC and Nd agreed more closely with the observations when the on-line aerosol was allowed to affect the cloud than when aerosol effects on cloud were not explicitly simulated. The increased cloud amount due to the aerosol effects reduced the modelled downward shortwave radiative flux and air temperature at the surface, contributing to a decrease in ozone over the region of enhanced cloud and an increase in particle sulphate from an increased capacity for aqueous-phase production. Aerosol activation is shown to have a significant influence on the cloud microphysics and cloud processing of trace gases and aerosols. The importance of reasonable parameterization of cloud updraft speed is demonstrated.
Interchannel coupling effects in the valence photoionization of SF6
NASA Astrophysics Data System (ADS)
Jose, J.; Lucchese, R. R.; Rescigno, T. N.
2014-05-01
The complex Kohn and polyatomic Schwinger variational techniques have been employed to illustrate the interchannel coupling correlation effects in the valence photoionization dynamics of SF6. Partial photoionization cross sections and asymmetry parameters of six valence subshells (1t1g, 5t1u, 1t2u, 3eg, 1t2g, 4t1u) are discussed in the framework of several theoretical and experimental studies. The complex Kohn results are in rather good agreement with experimental results, indicative of the fact that the interchannel coupling effects alter the photoionization dynamics significantly. We find that the dominant effect of interchannel coupling is to reduce the magnitude of shape resonant cross sections near the threshold and to induce resonant features in other channels to which resonances are coupled. The long-standing issue concerning ordering of the valence orbitals is addressed and confirmed 4t1u61t2g63eg4(5t1u6+1t2u6) 1t1g6 as the most likely ordering.
Dynamical Coupled-channels Effects on Pion Photoproduction
Julia-Diaz, B; Lee, T -S. H.; Matsuyama, A; Sato, T; Smith, L C
2007-12-18
The electromagnetic pion production reactions are investigated within the dynamical coupled-channels model developed in {\\bf Physics Reports, 439, 193 (2007)}. The meson-baryon channels included in this study are $\\gamma N$, $\\pi N$, $\\eta N$, and the $\\pi\\Delta$, $\\rho N$ and $\\sigma N$ resonant components of the $\\pi\\pi N$ channel. With the hadronic parameters of the model determined in a recent study of $\\pi N$ scattering, we show that the pion photoproduction data up to the second resonance region can be described to a very large extent by only adjusting the bare $\\gamma N \\rightarrow N^*$ helicity amplitudes, while the non-resonant electromagnetic couplings are taken from previous works. It is found that the coupled-channels effects can contribute about 10 - 20 $\\%$ of the production cross sections in the $\\Delta$ (1232) resonance region, and can drastically change the magnitude and shape of the cross sections in the second resonance region. The importance of the off-shell effects in a dynamical approach is also demonstrated. The meson cloud effects as well as the coupled-channels contributions to the $\\gamma N \\rightarrow N^*$ form factors are found to be mainly in the low $Q^2$ region. For the magnetic M1 $\\gamma N \\rightarrow \\Delta$ (1232) form factor, the results are close to that of the Sato-Lee Model. Necessary improvements to the model and future developments are discussed.
Inertial effect on spin–orbit coupling and spin transport
Basu, B. Chowdhury, Debashree
2013-08-15
We theoretically study the renormalization of inertial effects on the spin dependent transport of conduction electrons in a semiconductor by taking into account the interband mixing on the basis of k{sup →}⋅p{sup →} perturbation theory. In our analysis, for the generation of spin current we have used the extended Drude model where the spin–orbit coupling plays an important role. We predict enhancement of the spin current resulting from the renormalized spin–orbit coupling effective in our model in cubic and non-cubic crystals. Attention has been paid to clarify the importance of gauge fields in the spin transport of this inertial system. A theoretical proposition of a perfect spin filter has been done through the Aharonov–Casher like phase corresponding to this inertial system. For a time dependent acceleration, effect of k{sup →}⋅p{sup →} perturbation on the spin current and spin polarization has also been addressed. Furthermore, achievement of a tunable source of polarized spin current through the non uniformity of the inertial spin–orbit coupling strength has also been discussed. -- Highlights: •Study of the renormalization of inertial spin dependent transport of electrons. •Enhancement of the spin current due to the renormalized spin–orbit coupling. •A theoretical proposition of a perfect spin filter. •For a time dependent acceleration, spin current, spin polarization is addressed.
Shahmansouri, M.; Alinejad, H.
2015-04-15
We give a theoretical investigation on the dynamics of nonlinear electrostatic waves in a strongly coupled dusty plasma with strong electrostatic interaction between dust grains in the presence of the polarization force (i.e., the force due to the polarized Debye sheath). Adopting a reductive perturbation method, we derived a three-dimensional Kadomtsev-Petviashvili equation that describes the evolution of weakly nonlinear electrostatic localized waves. The energy integral equation is used to study the existence domains of the localized structures. The analysis provides the localized structure existence region, in terms of the effects of strong interaction between the dust particles and polarization force.
Qiu, Yongjian; Li, Meina; Pasoreck, Elise K.; Long, Lingyun; Shi, Yiting; Galvão, Rafaelo M.; Chou, Conrad L.; Wang, He; Sun, Amanda Y.; Zhang, Yiyin C.; Jiang, Anna; Chen, Meng
2015-01-01
Phytochromes (phys) are red and far-red photoreceptors that control plant development and growth by promoting the proteolysis of a family of antagonistically acting basic helix-loop-helix transcription factors, the PHYTOCHROME-INTERACTING FACTORs (PIFs). We have previously shown that the degradation of PIF1 and PIF3 requires HEMERA (HMR). However, the biochemical function of HMR and the mechanism by which it mediates PIF degradation remain unclear. Here, we provide genetic evidence that HMR acts upstream of PIFs in regulating hypocotyl growth. Surprisingly, genome-wide analysis of HMR- and PIF-dependent genes reveals that HMR is also required for the transactivation of a subset of PIF direct-target genes. We show that HMR interacts with all PIFs. The HMR-PIF interaction is mediated mainly by HMR’s N-terminal half and PIFs’ conserved active-phytochrome B binding motif. In addition, HMR possesses an acidic nine-amino-acid transcriptional activation domain (9aaTAD) and a loss-of-function mutation in this 9aaTAD impairs the expression of PIF target genes and the destruction of PIF1 and PIF3. Together, these in vivo results support a regulatory mechanism for PIFs in which HMR is a transcriptional coactivator binding directly to PIFs and the 9aaTAD of HMR couples the degradation of PIF1 and PIF3 with the transactivation of PIF target genes. PMID:25944101
A Dyadic Analysis of Relationships and Health: Does Couple-Level Context Condition Partner Effects?
Barr, Ashley B.; Simons, Ronald L.
2014-01-01
Adding to the growing literature explicating the links between romantic relationships and health, this study examined how both couple-level characteristics, particularly union type (e.g. dating, cohabiting, or marriage) and interracial pairing, and interpersonal characteristics (e.g. partner strain and support) predicted young adults’ physical and mental health. Using dyadic data from a sample of 249 young, primarily African American couples, we hypothesized and found support for the importance of couple-level context, partner behavior, and their interaction in predicting health. Interracial couples (all Black/non-Black pairings) reported worse health than monoracial Black couples. Union type, however, did not directly predict health but was a significant moderator of partner strain. That is, the negative association between partner strain and self-reported health was stronger for cohabiting and married couples versus their dating counterparts, suggesting that coresidence more so than marital status may be important for understanding partner effects on physical health. For psychological distress, however, partner support proved equally beneficial across union types. PMID:25090254
A dyadic analysis of relationships and health: does couple-level context condition partner effects?
Barr, Ashley B; Simons, Ronald L
2014-08-01
Adding to the growing literature explicating the links between romantic relationships and health, this study examined how both couple-level characteristics, particularly union type (e.g., dating, cohabiting, or marriage) and interracial pairing, and interpersonal characteristics (e.g., partner strain and support), predicted young adults' physical and mental health. Using dyadic data from a sample of 249 young, primarily Black couples, we hypothesized and found support for the importance of couple-level context, partner behavior, and their interaction in predicting health. Interracial couples (all Black/non-Black pairings) reported worse health than monoracial Black couples. Union type, however, did not directly predict health but was a significant moderator of partner strain. That is, the negative association between partner strain and self-reported health was stronger for cohabiting and married couples versus their dating counterparts, suggesting that coresidence, more so than marital status, may be important for understanding partner effects on physical health. For psychological distress, however, partner support proved equally beneficial across union types.
Adhesion effects in contact interaction of solids
NASA Astrophysics Data System (ADS)
Goryacheva, Irina; Makhovskaya, Yulya
2008-01-01
An approach to solving problems of the interaction of axisymmetric elastic bodies in the presence of adhesion is developed. The different natures of adhesion, i.e. capillary adhesion, or molecular adhesion described by the Lennard-Jones potential are examined. The effect of additional loading of the interacting bodies outside the contact zone is also investigated. The approach is based on the representation of the pressure outside the contact zone arising from adhesion by a step function. The analytical solution is obtained and is used to analyze the influence of the form of the adhesion interaction potential, of the surface energy of interacting bodies or the films covering the bodies, their shapes (parabolic, higher power exponential function), volume of liquid in the meniscus, density of contact spots, of elastic modulus and the Poisson ratio on the characteristics of the interaction of the bodies in the presence of adhesion. To cite this article: I. Goryacheva, Y. Makhovskaya, C. R. Mecanique 336 (2008).
Kondo effect in a quantum dot side-coupled to a topological superconductor
NASA Astrophysics Data System (ADS)
Lee, Minchul; Lim, Jong Soo; López, Rosa
2013-06-01
We investigate the dynamical and transport features of a Kondo dot side coupled to a topological superconductor (TS). The Majorana fermion states (MFSs) formed at the ends of the TS are found to be able to alter the Kondo physics profoundly: For an infinitely long wire where the MFSs do not overlap (ɛm=0) a finite dot-MFS coupling (Γm) reduces the unitary-limit value of the linear conductance by exactly a factor 3/4 in the weak-coupling regime (Γm
Effect of temperature coupling on ozone depletion prediction
NASA Technical Reports Server (NTRS)
Chandra, S.; Butler, D. M.; Stolarski, R. S.
1978-01-01
The effects of chlorine perturbations on both the temperature and the ozone distribution in the stratosphere have been studied using a simplified radiative-photochemical model. The model solves the hydrostatic equation for total density in a self-consistent manner as the temperature is changed. Radiative coupling is found to have a significant effect on both the thermal structure and the ozone distribution, particularly in the 35-50-km region. By increasing the ClX mixing ratio by 5.0 ppbv, the temperature in this region is decreased by 5 to 10 K with a slight increase below 30 km. The local ozone depletion around 40 km due to added ClX is smaller compared with the estimate made by keeping the temperature fixed to the ambient condition. However, the integrated effect of radiative coupling is to increase the calculated column ozone depletion by 15% to 25% in this model.
Effective dipole moment for the mode coupling instability: Mapping of self-consistent wake models
Roecker, T. B.; Zhdanov, S. K.; Ivlev, A. V.; Morfill, G. E.; Lampe, M.; Joyce, G.
2012-07-15
The theory of the mode coupling instability operating in two-dimensional plasma crystals is generalized, by employing the linear plasma response formalism to describe the interparticle interactions self-consistently. In this approach, the underlying ion distribution function is calculated from first principles. Subthermal and suprathermal regimes of the ion flow are considered. A mapping procedure is proposed, which relates the self-consistent coupling coefficients to the effective dipole moment of the wake-the parameter which characterizes the mode coupling in the framework of the conventionally used Yukawa/point-wake model. The importance of the self-consistent approach is demonstrated by comparing the theoretically obtained dipole moments with the values deduced from experiments.
Interaction of beef-heart mitochondrial ATPase, coupling factor F1, with aurovertin.
Yeates, R A
1974-02-22
The antibiotic aurovertin binds to beef-heart mitochondrial ATPase, coupling Factor F1, with biphasic fluorescence enhancement. Specific binding effects, polarity and viscosity changes may all contribute to the enhancement. Evidence is presented that it stems from aurovertin binding followed by a slow conformational change in F1. This occurs more rapidly in dissociated F1. The effect of substrates of the enzyme on the fluorescence enhancement is examined. Evidence is presented that in the absence of added magnesium, F1 can hydrolyse low concentrations of added ATP.
Soleimani, Ali Akbar; Najafi, Maryam; Ahmadi, Khodabakhsh; Javidi, Nasirudin; Hoseini Kamkar, Elnaz; Mahboubi, Mohamad
2015-01-01
Background The purpose of this investigation is to determine the efficacy of emotionally focused couples therapy (EFT-C) on enhancement of marital adjustment in infertile couples. Materials and Methods This was a semi-experimental study with a pre- and post-test design. We selected 30 infertile couples (60 subjects) by purposive sampling. Couples were randomly assigned to two groups, sample and control. Each group consisted of 15 couples who had marital maladjustment and low sexual satisfaction. Couples answered the marital adjustment and sexual satisfaction questionnaires at baseline after which the sample group received 10 sessions of EFT-C. Results Results of pre-test and post-test showed that EFT-C significantly impacted marital adjustment and sexual satisfaction. Conclusion EFT-C had a significant effect on enhancement of satisfaction, cohesion and affectional expression. This approach impacted physical and emotional sexual satisfaction of infertile couples. PMID:26644864
Effect of proton transfer on the electronic coupling in DNA
NASA Astrophysics Data System (ADS)
Rak, Janusz; Makowska, Joanna; Voityuk, Alexander A.
2006-06-01
The effects of single and double proton transfer within Watson-Crick base pairs on donor-acceptor electronic couplings, Vda, in DNA are studied on the bases of quantum chemical calculations. Four dimers [AT,AT], [GC,GC], [GC,AT] and [GC,TA)] are considered. Three techniques - the generalized Mulliken-Hush scheme, the fragment charge method and the diabatic states method - are employed to estimate Vda for hole transfer between base pairs. We show that both single- and double proton transfer (PT) reactions may substantially affect the electronic coupling in DNA. The electronic coupling in [AT,AT] is predicted to be most sensitive to PT. Single PT within the first base pair in the dimer leads to increase in the hole transfer efficiency by a factor of 4, while proton transfer within the second pair should substantially, by 2.7 times, decrease the rate of charge transfer. Thus, directional asymmetry of the PT effects on the electronic coupling is predicted. The changes in the Vda matrix elements correlate with the topological properties of orbitals of donor and acceptor and can be qualitatively rationalized in terms of resonance structures of donor and acceptor. Atomic pair contributions to the Vda matrix elements are also analyzed.
Effect of strong coupling on dust acoustic waves and instabilities
Rosenberg, M.; Kalman, G.
1998-10-21
The presence of charged dust in a plasma can lead to very low frequency dust acoustic waves and instabilities. In certain laboratory plasmas the dust is strongly coupled, as characterized by the condition {gamma}{sub d}=Q{sub d}{sup 2} exp(-d/{lambda}{sub D})/dT{sub d}{>=}1, where Q{sub d} is the dust charge, d is the intergrain spacing, T{sub d} is the dust thermal energy, and {lambda}{sub D} is the plasma screening length. When the dust is strongly coupled, the spatial correlation of the grains can affect the dispersion relation of these waves. We review our recent work [1] on the dispersion properties of dust acoustic waves in the strongly coupled (liquid) phase in a dusty plasma, including also the effects of dust-neutral collisions. We then discuss a preliminary analysis of the effect of strong dust coupling on an ion dust two-stream instability in a collisional dusty plasma. Applications to laboratory dusty plasmas are discussed.
Effect of strong coupling on dust acoustic waves and instabilities
Rosenberg, M. Kalman, G.
1998-10-01
The presence of charged dust in a plasma can lead to very low frequency dust acoustic waves and instabilities. In certain laboratory plasmas the dust is strongly coupled, as characterized by the condition {Gamma}{sub d}=Q{sub d}{sup 2} exp({minus}d/{lambda}{sub D})/dT{sub d}{ge}1, where Q{sub d} is the dust charge, {ital d} is the intergrain spacing, T{sub d} is the dust thermal energy, and {lambda}{sub D} is the plasma screening length. When the dust is strongly coupled, the spatial correlation of the grains can affect the dispersion relation of these waves. We review our recent work [1] on the dispersion properties of dust acoustic waves in the strongly coupled (liquid) phase in a dusty plasma, including also the effects of dust-neutral collisions. We then discuss a preliminary analysis of the effect of strong dust coupling on an ion dust two-stream instability in a collisional dusty plasma. Applications to laboratory dusty plasmas are discussed. {copyright} {ital 1998 American Institute of Physics.}
Dynamical coupled-channels effects on pion photoproduction
Julia-Diaz, B.; Lee, T.-S. H.; Matsuyama, A.; Sato, T.; Smith, L. C.
2008-04-15
The electromagnetic pion production reactions are investigated within the dynamical coupled-channels model developed by Matsuyama, Sato, and Lee [Phys. Rep. 439, 193 (2007)]. The meson-baryon channels included in this study are {gamma}N,{pi}N,{eta}N, and the {pi}{delta},{rho}N, and {sigma}N resonant components of the {pi}{pi}N channel. With the hadronic parameters of the model determined in a recent study of {pi}N scattering, we show that the pion photoproduction data up to the second resonance region can be described to a very large extent by only adjusting the bare {gamma}N{yields}N* helicity amplitudes, while the nonresonant electromagnetic couplings are taken from previous works. It is found that the coupled-channels effects can contribute about 30-40 % of the production cross sections in the {delta} (1232) resonance region, and can drastically change the magnitude and shape of the cross sections in the second resonance region. The importance of the loop-integrations in a dynamical approach is also demonstrated. The meson cloud effects as well as the coupled-channels contributions to the {gamma}N{yields}N* form factors are found to be mainly in the low Q{sup 2} region. Necessary improvements to the model and future developments are discussed.
Closed system of coupling effects in generalized thermo-elastoplasticity
NASA Astrophysics Data System (ADS)
Śloderbach, Z.
2016-05-01
In this paper, the field equations of the generalized coupled thermoplasticity theory are derived using the postulates of classical thermodynamics of irreversible processses. Using the Legendre transformations two new thermodynamics potentials P and S depending upon internal thermodynamic forces Π are introduced. The most general form for all the thermodynamics potentials are assumed instead of the usually used additive form. Due to this assumption, it is possible to describe all the effects of thermomechanical couples and also the elastic-plastic coupling effects observed in such materials as rocks, soils, concretes and in some metalic materials. In this paper not only the usual postulate of existence of a dissipation qupotential (the Gyarmati postulate) is used to derive the velocity equation. The plastic flow constitutive equations have the character of non-associated flow laws even when the Gyarmati postulate is assumed. In general formulation, the plastic strain rate tensor is normal to the surface of the generalized function of plastic flow defined in the the space of internal thermodynamic forces Π but is not normal to the yield surface. However, in general formulation and after the use the Gyarmati postulate, the direction of the sum of the plastic strain rate tensor and the coupled elastic strain rate tensor is normal to the yield surface.
Navarrete, Sergio A.; Wieters, Evie A.; Broitman, Bernardo R.; Castilla, Juan Carlos
2005-01-01
Large and usually unpredictable variation in species interaction strength has been a major roadblock to applying local experimental results to large-scale management and conservation issues. Recent studies explicitly considering benthic-pelagic coupling are starting to shed light on, and find regularities in, the causes of such large-scale variation in coastal ecosystems. Here, we evaluate the effects of variation in wind-driven upwelling on community regulation along 900 km of coastline of the southeastern Pacific, between 29°S and 35°S during 72 months. Variability in the intensity of upwelling occurring over tens of km produced predictable variation in recruitment of intertidal mussels, but not barnacles, and did not affect patterns of community structure. In contrast, sharp discontinuities in upwelling regimes produced abrupt and persistent breaks in the dynamics of benthic and pelagic communities over hundreds of km (regional) scales. Rates of mussel and barnacle recruitment changed sharply at ≈32°-33°S, determining a geographic break in adult abundance of these competitively dominant species. Analysis of satellite images demonstrates that regional-scale discontinuities in oceanographic regimes can couple benthic and pelagic systems, as evidenced by coincident breaks in dynamics and concentration of offshore surface chlorophyll-a. Field experiments showed that the paradigm of top-down control of intertidal benthic communities holds only south of the discontinuity. To the north, populations seem recruitment-limited, and predators have negligible effects, despite attaining similarly high abundances and potential predation effects across the region. Thus, geographically discontinuous oceanographic regimes set bounds to the strength of species interactions and define distinct regions for the design and implementation of sustainable management and conservation policies. PMID:16332959
Competition between spin-orbit interaction and exchange coupling within a honeycomb lattice ribbon
NASA Astrophysics Data System (ADS)
Su, Yu-Hsin; Chen, Son-Hsien; Hu, C. D.; Chang, Ching-Ray
2016-01-01
Spin density patterns of a pinned magnetic impurity that is embedded in a honeycomb lattice with zigzag edges are investigated by employing a mean-field assisted Landauer-Keldysh formalism. Both the intrinsic spin-orbit coupling and the extrinsic localized magnetic moments are considered, and the effects of the pinning directions and the species of the sublattice on the electron spins are analyzed. A local time-reversal symmetry breaking cannot destroy the equilibrium edge-state spin accumulation that is induced by intrinsic spin-orbit coupling when the pinning field lies in the plane of the ribbon and the embedding position is the A-site at the edge. The induced local spin can be either parallel or antiparallel to the localized impurity moment, depending on the location of the pinned impurity, because itinerant electrons are found only at the B-site of the edge, but not at the A-site.
NASA Astrophysics Data System (ADS)
de la Cita, V. M.; Bosch-Ramon, V.; Paredes-Fortuny, X.; Khangulyan, D.; Perucho, M.
2016-06-01
Context. Stars and their winds can contribute to the non-thermal emission in extragalactic jets. Because of the complexity of jet-star interactions, the properties of the resulting emission are closely linked to those of the emitting flows. Aims: We simulate the interaction between a stellar wind and a relativistic extragalactic jet and use the hydrodynamic results to compute the non-thermal emission under different conditions. Methods: We performed relativistic axisymmetric hydrodynamical simulations of a relativistic jet interacting with a supersonic, non-relativistic stellar wind. We computed the corresponding streamlines out of the simulation results and calculated the injection, evolution, and emission of non-thermal particles accelerated in the jet shock, focusing on electrons or e±-pairs. Several cases were explored, considering different jet-star interaction locations, magnetic fields, and observer lines of sight. The jet luminosity and star properties were fixed, but the results are easily scalable when these parameters are changed. Results: Individual jet-star interactions produce synchrotron and inverse Compton emission that peaks from X-rays to MeV energies (depending on the magnetic field), and at ~100-1000 GeV (depending on the stellar type), respectively. The radiation spectrum is hard in the scenarios explored here as a result of non-radiative cooling dominance, as low-energy electrons are efficiently advected even under relatively high magnetic fields. Interactions of jets with cold stars lead to an even harder inverse Compton spectrum because of the Klein-Nishina effect in the cross section. Doppler boosting has a strong effect on the observer luminosity. Conclusions: The emission levels for individual interactions found here are in the line of previous, more approximate, estimates, strengthening the hypothesis that collective jet-star interactions could significantly contribute at high energies under efficient particle acceleration.
Effective Dynamics of Microorganisms That Interact with Their Own Trail.
Kranz, W Till; Gelimson, Anatolij; Zhao, Kun; Wong, Gerard C L; Golestanian, Ramin
2016-07-15
Like ants, some microorganisms are known to leave trails on surfaces to communicate. We explore how trail-mediated self-interaction could affect the behavior of individual microorganisms when diffusive spreading of the trail is negligible on the time scale of the microorganism using a simple phenomenological model for an actively moving particle and a finite-width trail. The effective dynamics of each microorganism takes on the form of a stochastic integral equation with the trail interaction appearing in the form of short-term memory. For a moderate coupling strength below an emergent critical value, the dynamics exhibits effective diffusion in both orientation and position after a phase of superdiffusive reorientation. We report experimental verification of a seemingly counterintuitive perpendicular alignment mechanism that emerges from the model. PMID:27472143
Effective Dynamics of Microorganisms That Interact with Their Own Trail
NASA Astrophysics Data System (ADS)
Kranz, W. Till; Gelimson, Anatolij; Zhao, Kun; Wong, Gerard C. L.; Golestanian, Ramin
2016-07-01
Like ants, some microorganisms are known to leave trails on surfaces to communicate. We explore how trail-mediated self-interaction could affect the behavior of individual microorganisms when diffusive spreading of the trail is negligible on the time scale of the microorganism using a simple phenomenological model for an actively moving particle and a finite-width trail. The effective dynamics of each microorganism takes on the form of a stochastic integral equation with the trail interaction appearing in the form of short-term memory. For a moderate coupling strength below an emergent critical value, the dynamics exhibits effective diffusion in both orientation and position after a phase of superdiffusive reorientation. We report experimental verification of a seemingly counterintuitive perpendicular alignment mechanism that emerges from the model.
Propulsive effects of vortex coupling between parallel pulsed jets
NASA Astrophysics Data System (ADS)
Athanassiadis, Athanasios; Hart, Douglas
2015-11-01
For vehicles that use pulsed jet propulsion, nature provides inspiration for different ways to improve propulsive performance. Communities of marine invertebrates called salps improve the efficiency of cruising locomotion by aggregating into large multi-animal chains. In this process, the cylindrical animals physically connect to each other side-by-side to form an array of individual pulsed jets whose synchronous pulsing propels the entire chain forward. Some benefits of this chaining behavior can be described using existing models of pulsed jet propulsion for steady, cruising conditions. However, during unsteady conditions such as impulsive maneuvering at low speeds, it remains unclear how interactions between neighboring jets will affect the chain's propulsive performance. Using bench-top experiments, we investigate the unsteady interactions between two parallel pulsed jets. Under some conditions, the pulsed jets form vortex rings that coalesce before vortex formation is complete, coupling the hydrodynamics of the independent jets. We measure how different degrees of vortex coupling alter the energy and momentum transfer in the two-jet system. Finally, we explore the energy and momentum scalings that would guide the design of a vehicle using multi-jet maneuvering techniques. This work was supported by the Office of Naval Research.
Phase and frequency entrainment in locally coupled phase oscillators with repulsive interactions
NASA Astrophysics Data System (ADS)
Giver, Michael; Jabeen, Zahera; Chakraborty, Bulbul
2011-03-01
Recent experiments in one and two-dimensional microfluidic arrays of droplets containing Belousov - Zhabotinsky reactants show a rich variety of spatial patterns [J. Phys. Chem. Lett. 1, 1241-1246 (2010)]. These experiments provide the first steps towards creating easily reproducible model active emulsion systems. Motivated by this experimental system, we study repulsively coupled Kuramoto oscillators with nearest neighbor interactions on a linear chain as well as a ring in one dimension. We show using linear stability analysis as well as numerical study, that the stable phase patterns depend on the geometry of the lattice and that a transition to the ordered state does not exist in the thermodynamic limit. We will also present results comparing our Kuramoto model with finite element simulations of the Brusselator model in geometries similar to those of the experiment.
NASA Astrophysics Data System (ADS)
Kumar, Sanjay; Ajay
2015-01-01
Stacking dependent quasi-particle spectrum and density of states (DOS) in trilayer (ABC-, ABA- and AAA-stacked) graphene are analyzed using mean-field Green's function equations of motion method. Interlayer coupling (t1) is found to be responsible for the splitting of quasi-particle peaks in each stacking order. Coulomb interaction suppresses the trilayer splitting and generates a finite gap at Fermi level in ABC- while a tiny gap in ABA-stacked trilayer graphene. Influence of t⊥ is prominent for AAA-stacking as compared to ABC- and ABA-stacking orders. The theoretically obtained quasi-particle energies and DOS has been viewed in terms of recent angle resolved photoemission spectroscopic (ARPES) and scanning tunneling microscopic (STM) data available on these systems.
Static black hole solutions with a self-interacting conformally coupled scalar field
Dotti, Gustavo; Gleiser, Reinaldo J.; Martinez, Cristian
2008-05-15
We study static, spherically symmetric black hole solutions of the Einstein equations with a positive cosmological constant and a conformally coupled self-interacting scalar field. Exact solutions for this model found by Martinez, Troncoso, and Zanelli were subsequently shown to be unstable under linear gravitational perturbations, with modes that diverge arbitrarily fast. We find that the moduli space of static, spherically symmetric solutions that have a regular horizon--and satisfy the weak and dominant energy conditions outside the horizon--is a singular subset of a two-dimensional space parametrized by the horizon radius and the value of the scalar field at the horizon. The singularity of this space of solutions provides an explanation for the instability of the Martinez, Troncoso, and Zanelli spacetimes and leads to the conclusion that, if we include stability as a criterion, there are no physically acceptable black hole solutions for this system that contain a cosmological horizon in the exterior of its event horizon.
Strongly coupled partitioned approach for fluid structure interaction in free surface flows
NASA Astrophysics Data System (ADS)
Facci, Andrea Luigi; Ubertini, Stefano
2016-06-01
In this paper we describe and validate a methodology for the numerical simulation of the fluid structure interaction in free surface flows. Specifically, this study concentrates on the vertical impact of a rigid body on the water surface, (i.e. on the hull slamming problem). The fluid flow is modeled through the volume of fluid methodology, and the structure dynamics is described by the Newton's second law. An iterative algorithm guarantees the tight coupling between the fluid and solid solvers, allowing the simulations of lightweight (i.e. buoyant) structures. The methodology is validated comparing numerical results to experimental data on the free fall of different rigid wedges. The correspondence between numerical results and independent experimental findings from literature evidences the reliability and the accuracy of the proposed approach.
Mahowald, Natalie; Rothenberg, D.; Lindsay, Keith; Doney, Scott C.; Moore, Jefferson Keith; Randerson, James T.; Thornton, Peter E; Jones, C. D.
2011-02-01
Coupled-carbon-climate simulations are an essential tool for predicting the impact of human activity onto the climate and biogeochemistry. Here we incorporate prognostic desert dust and anthropogenic aerosols into the CCSM3.1 coupled carbon-climate model and explore the resulting interactions with climate and biogeochemical dynamics through a series of transient anthropogenic simulations (20th and 21st centuries) and sensitivity studies. The inclusion of prognostic aerosols into this model has a small net global cooling effect on climate but does not significantly impact the globally averaged carbon cycle; we argue that this is likely to be because the CCSM3.1 model has a small climate feedback onto the carbon cycle. We propose a mechanism for including desert dust and anthropogenic aerosols into a simple carbon-climate feedback analysis to explain the results of our and previous studies. Inclusion of aerosols has statistically significant impacts on regional climate and biogeochemistry, in particular through the effects on the ocean nitrogen cycle and primary productivity of altered iron inputs from desert dust deposition.
Écija, Patricia; Cocinero, Emilio J; Lesarri, Alberto; Millán, Judith; Basterretxea, Francisco; Fernández, José A; Castaño, Fernando
2011-04-28
The intrinsic conformational and structural properties of the bicycle exo-2-aminonorbornane have been probed in a supersonic jet expansion using Fourier-transform microwave (FT-MW) spectroscopy and quantum chemical calculations. The rotational spectrum revealed two different conformers arising from the internal rotation of the amino group, exhibiting small (MHz) hyperfine patterns originated by the (14)N nuclear quadrupole coupling interaction. Complementary ab initio (MP2) and DFT (B3LYP and M05-2X) calculations provided comparative predictions for the structural properties, rotational and centrifugal distortion data, hyperfine parameters, and isomerization barriers. Due to the similarity of the rotational constants, the structural assignment of the observed rotamers and the calculation of the torsion angles of the amino group were based on the conformational dependence of the (14)N nuclear quadrupole coupling hyperfine tensor. In the most stable conformation (ss), the two amino N-H bonds are staggered with respect to the adjacent C-H bond. In the second conformer (st), only one of the N-H bonds is staggered and the other is trans. A third predicted conformer (ts) was not detected, consistent with a predicted conformational relaxation to conformer ss through a low barrier of 5.2 kJ mol(-1).
NASA Astrophysics Data System (ADS)
McNamara, D. E.; Werner, B. T.
2008-03-01
As humans increasingly occupy and modify marginal landscapes, previously unobserved long timescale, emergent behaviors related to interactions between natural processes and human agency are possible. Barrier islands, which are low-lying strips of sand separated from a coast by lagoons, cut by inlets and topped by sand dunes, have been significantly modified through the development of tourist resorts. Resorts and barrier islands are dynamically coupled through storm damage and beach erosion, and measures taken to prevent or mitigate them. In response to rising sea level, a natural barrier island migrates steadily up the continental shelf. In contrast, we show that in a novel numerical model-coupling barrier island processes with resort development, storm damage, and hazard mitigation, policy decisions driven by market dynamics destabilize barrier island response to rising sea level, giving rise to emergent, episodic boom and bust cycles, which alternate in phase alongshore, and less frequent, regionally extensive resort destruction events. Developed barrier islands are precariously maintained at lower elevations and further offshore than their natural counterparts, a situation exacerbated by insurance, which can lead to island inundation. Our results suggest that coastal areas that have recently instituted protection measures eventually will experience a widespread upsurge in damage if these practices are sustained, even in the absence of climate-change-induced increased storminess.
Emergence of global scaling behaviour in the coupled Earth-atmosphere interaction
Fallah, Bijan; Saberi, Abbas Ali; Sodoudi, Sahar
2016-01-01
Scale invariance property in the global geometry of Earth may lead to a coupled interactive behaviour between various components of the climate system. One of the most interesting correlations exists between spatial statistics of the global topography and the temperature on Earth. Here we show that the power-law behaviour observed in the Earth topography via different approaches, resembles a scaling law in the global spatial distribution of independent atmospheric parameters. We report on observation of scaling behaviour of such variables characterized by distinct universal exponents. More specifically, we find that the spatial power-law behaviour in the fluctuations of the near surface temperature over the lands on Earth, shares the same universal exponent as of the global Earth topography, indicative of the global persistent role of the static geometry of Earth to control the steady state of a dynamical atmospheric field. Such a universal feature can pave the way to the theoretical understanding of the chaotic nature of the atmosphere coupled to the Earth’s global topography. PMID:27666675
Emergence of global scaling behaviour in the coupled Earth-atmosphere interaction
NASA Astrophysics Data System (ADS)
Fallah, Bijan; Saberi, Abbas Ali; Sodoudi, Sahar
2016-09-01
Scale invariance property in the global geometry of Earth may lead to a coupled interactive behaviour between various components of the climate system. One of the most interesting correlations exists between spatial statistics of the global topography and the temperature on Earth. Here we show that the power-law behaviour observed in the Earth topography via different approaches, resembles a scaling law in the global spatial distribution of independent atmospheric parameters. We report on observation of scaling behaviour of such variables characterized by distinct universal exponents. More specifically, we find that the spatial power-law behaviour in the fluctuations of the near surface temperature over the lands on Earth, shares the same universal exponent as of the global Earth topography, indicative of the global persistent role of the static geometry of Earth to control the steady state of a dynamical atmospheric field. Such a universal feature can pave the way to the theoretical understanding of the chaotic nature of the atmosphere coupled to the Earth’s global topography.
Anomalous coupling, top-mass and parton-shower effects in W + W - production
NASA Astrophysics Data System (ADS)
Bellm, J.; Gieseke, S.; Greiner, N.; Heinrich, G.; Plätzer, S.; Reuschle, C.; von Soden-Fraunhofen, J. F.
2016-05-01
We calculate the process ppto {W}+{W}-to {e}+{ν}_e{μ}-{overline{ν}}_{μ } at NLO QCD, including also effective field theory (EFT) operators mediating the ggW + W - interaction, which first occur at dimension eight. We further combine the NLO and EFT matrix elements produced by G oS am with the H erwig7/M atchbox framework, which offers the possibility to study the impact of a parton shower. We assess the effects of the anomalous couplings by comparing them to top-mass effects as well as uncertainties related to variations of the renormalisation, factorisation and hard shower scales.
Electromagnetic interactions in a chiral effective lagrangian for nuclei
Serot, Brian D.
2007-12-15
Electromagnetic (EM) interactions are incorporated in a recently proposed effective field theory of the nuclear many-body problem. Earlier work with this effective theory exhibited EM couplings that are correct only to lowest order in both the pion fields and the electric charge. The Lorentz-invariant effective field theory contains nucleons, pions, isoscalar scalar ({sigma}) and vector ({omega}) fields, and isovector vector ({rho}) fields. The theory exhibits a nonlinear realization of SU(2){sub L} x SU(2){sub R} chiral symmetry and has three desirable features: it uses the same degrees of freedom to describe the currents and the strong-interaction dynamics, it satisfies the symmetries of the underlying QCD, and its parameters can be calibrated using strong-interaction phenomena, like hadron scattering or the empirical properties of finite nuclei. It has been verified that for normal nuclear systems, the effective lagrangian can be expanded systematically in powers of the meson fields (and their derivatives) and can be truncated reliably after the first few orders. The complete EM lagrangian arising from minimal substitution is derived and shown to possess the residual chiral symmetry of massless, two-flavor QCD with EM interactions. The uniqueness of the minimal EM current is proved, and the properties of the isovector vector and axial-vector currents are discussed, generalizing earlier work. The residual chiral symmetry is maintained in additional (non-minimal) EM couplings expressed as a derivative expansion and in implementing vector meson dominance. The role of chiral anomalies in the EM lagrangian is briefly discussed.
Effective Theories Of The Strong Interaction
Dr. Ubirajara van Kolck
2004-07-31
This is the final report corresponding to the full funding period (08/01-07/04) in the Department of Energy Outstanding Junior Investigator Grant DE-FG03-01ER41196. The development of an understanding of the interplay between perturbative and non-perturbative effects in strong-interacting systems forms the broad context of this research. The main thrust is the application of effective theories to QCD. Topics included a new power counting in the pionful effective theory, low-energy Compton scattering, charge-symmetry breaking in pion production and in the two-nucleon potential, parity violation, coupled-channel scattering, shallow resonances and halo nuclei, chiral symmetry in the baryon spectrum, existence of a tetraquark state, and molecular meson states. DOE grant DE-FG03-01ER41196 was used to partially support in the period 08/01-07/04 the research activities of the Principal Investigator, Dr. Ubirajara van Kolck, one post-doctoral research associate, Dr. Boris A. Gelman, and one graduate student, Mr. Will Hockings. During the grant period the PI was first Assistant then Associate Professor of Physics at the University of Arizona (UA), and a RHIC Physics Fellow at the RIKEN-BNL Research Center (RBRC). The association with RBRC ended in the Summer of 2004. Since September of 2002 the PI has also been partially supported by a Sloan Research Fellowship. Dr. Boris Gelman was supported by the grant from September 2002 to May 2004. He joined the UA after receiving a Ph.D. from the University of Maryland in the Summer of 2002. He left to take a research associate position in the nuclear theory group of the State University of New York at Stony Brook. The support of a post-doctoral researcher on this grant for two years was only possible by carrying over first- and second-year funds to later years. In addition, Mr. William Hockings started doing research under the PI's guidance. Mr. Hockings took Independent Study courses with the PI, while working as a teaching
NASA Astrophysics Data System (ADS)
Ding, Mingnan; Liang, Yihao; Xing, Xiangjun
2016-10-01
In this work, we explore the statistical physics of colloidal particles that interact with electrolytes via ion-specific interactions. Firstly we study particles interacting weakly with electrolyte using linear response theory. We find that the mean potential around a particle is linearly determined by the effective charge distribution of the particle, which depends both on the bare charge distribution and on ion-specific interactions. We also discuss the effective interaction between two such particles and show that, in the far field regime, it is bilinear in the effective charge distributions of two particles. We subsequently generalize the above results to the more complicated case where particles interact strongly with the electrolyte. Our results indicate that in order to understand the statistical physics of non-dilute electrolytes, both ion-specific interactions and ionic correlations have to be addressed in a single unified and consistent framework. Project supported by the National Natural Science Foundation of China (Grant Nos. 11174196 and 91130012).
Fridlyand, Leonid E; Philipson, Louis H
2016-01-01
Insulin secretory in pancreatic beta-cells responses to nutrient stimuli and hormonal modulators include multiple messengers and signaling pathways with complex interdependencies. Here we present a computational model that incorporates recent data on glucose metabolism, plasma membrane potential, G-protein-coupled-receptors (GPCR), cytoplasmic and endoplasmic reticulum calcium dynamics, cAMP and phospholipase C pathways that regulate interactions between second messengers in pancreatic beta-cells. The values of key model parameters were inferred from published experimental data. The model gives a reasonable fit to important aspects of experimentally measured metabolic and second messenger concentrations and provides a framework for analyzing the role of metabolic, hormones and neurotransmitters changes on insulin secretion. Our analysis of the dynamic data provides support for the hypothesis that activation of Ca2+-dependent adenylyl cyclases play a critical role in modulating the effects of glucagon-like peptide 1 (GLP-1), glucose-dependent insulinotropic polypeptide (GIP) and catecholamines. The regulatory properties of adenylyl cyclase isoforms determine fluctuations in cytoplasmic cAMP concentration and reveal a synergistic action of glucose, GLP-1 and GIP on insulin secretion. On the other hand, the regulatory properties of phospholipase C isoforms determine the interaction of glucose, acetylcholine and free fatty acids (FFA) (that act through the FFA receptors) on insulin secretion. We found that a combination of GPCR agonists activating different messenger pathways can stimulate insulin secretion more effectively than a combination of GPCR agonists for a single pathway. This analysis also suggests that the activators of GLP-1, GIP and FFA receptors may have a relatively low risk of hypoglycemia in fasting conditions whereas an activator of muscarinic receptors can increase this risk. This computational analysis demonstrates that study of second messenger
Fridlyand, Leonid E.; Philipson, Louis H.
2016-01-01
Insulin secretory in pancreatic beta-cells responses to nutrient stimuli and hormonal modulators include multiple messengers and signaling pathways with complex interdependencies. Here we present a computational model that incorporates recent data on glucose metabolism, plasma membrane potential, G-protein-coupled-receptors (GPCR), cytoplasmic and endoplasmic reticulum calcium dynamics, cAMP and phospholipase C pathways that regulate interactions between second messengers in pancreatic beta-cells. The values of key model parameters were inferred from published experimental data. The model gives a reasonable fit to important aspects of experimentally measured metabolic and second messenger concentrations and provides a framework for analyzing the role of metabolic, hormones and neurotransmitters changes on insulin secretion. Our analysis of the dynamic data provides support for the hypothesis that activation of Ca2+-dependent adenylyl cyclases play a critical role in modulating the effects of glucagon-like peptide 1 (GLP-1), glucose-dependent insulinotropic polypeptide (GIP) and catecholamines. The regulatory properties of adenylyl cyclase isoforms determine fluctuations in cytoplasmic cAMP concentration and reveal a synergistic action of glucose, GLP-1 and GIP on insulin secretion. On the other hand, the regulatory properties of phospholipase C isoforms determine the interaction of glucose, acetylcholine and free fatty acids (FFA) (that act through the FFA receptors) on insulin secretion. We found that a combination of GPCR agonists activating different messenger pathways can stimulate insulin secretion more effectively than a combination of GPCR agonists for a single pathway. This analysis also suggests that the activators of GLP-1, GIP and FFA receptors may have a relatively low risk of hypoglycemia in fasting conditions whereas an activator of muscarinic receptors can increase this risk. This computational analysis demonstrates that study of second messenger
Effective Supergravity from the Weakly Coupled HeteroticString
Gaillard, Mary K.
2005-05-01
The motivation for Calabi-Yau-like compactifications of the weakly coupled E{sub 8} {circle_times} E{sub 8} heterotic string theory, its particle spectrum and the issue of dilaton stabilization are briefly reviewed. Modular invariant models for hidden sector condensation and supersymmetry breaking are described at the quantum level of the effective field theory. Their phenomenological and cosmological implications, including a possible origin for R-parity, are discussed.
Planning for effective interaction with FDA.
Spurgin, Elizabeth A
2004-12-01
Manufacturers of diabetes devices can facilitate the formal regulatory approval process through early interaction with the U.S. Food and Drug Administration (FDA). Effective planning can help manage commonly perceived risks of interaction with the Agency, introduce new technologies to regulatory reviewers, and inform the manufacturer's product development strategy. This article reviews key aspects of the FDA evaluation process and suggests strategies that may facilitate effective communication with the Agency. Integrating early communication with FDA into broader product commercialization planning can streamline regulatory review and lead to early product launch into reimbursed markets.
NASA Astrophysics Data System (ADS)
Klein, C.; Hoffmann, P.; Priesack, E.
2012-04-01
Climate change causes altering distributions of meteorological factors influencing plant growth and its interactions between the land surface and the atmosphere. Recent studies show, that uncertainties in regional and global climate simulations are also caused by lacking descriptions of the soil-plant-atmosphere system. Therefore, we couple a mechanistic soil-plant model to a regional climate and forecast model. The detailed simulation of the water and energy exchanges, especially the transpiration of grassland and forests stands, are the key features of the modelling framework. The Weather Research and Forecasting model (WRF) (Skamarock 2008) is an open source mesoscale numerical weather prediction model. The WRF model was modified in a way, to either choose its native, static land surface model NOAH or the mechanistic eco-system model Expert-N 5.0 individually for every single grid point within the simulation domain. The Expert-N 5.0 modelling framework provides a highly modular structure, enabling the development and use of a large variety of different plant and soil models, including heat transfer, nitrogen uptake/turnover/transport as well as water uptake/transport and crop management. To represent the key landuse types grassland and forest, we selected two mechanistic plant models: The Hurley Pasture model (Thornley 1998) and a modified TREEDYN3 forest simulation model (Bossel 1996). The models simulate plant growth, water, nitrogen and carbon flows for grassland and forest stands. A mosaic approach enables Expert-N to use high resolution land use data e.g. CORINE Land Cover data (CLC, 2006) for the simulation, making it possible to simulate different land use distributions within a single grid cell. The coupling results are analyzed for plausibility and compared with the results of the default land surface model NOAH (Fei Chen and Jimy Dudhia 2010). We show differences between the mechanistic and the static model coupling, with focus on the feedback effects
Spectral density of an interacting dot coupled indirectly to conducting leads
NASA Astrophysics Data System (ADS)
Vaugier, L.; Aligia, A. A.; Lobos, A. M.
2007-10-01
We study the spectral density of electrons ρdσ(ω) in an interacting quantum dot (QD) with a hybridization λ to a noninteracting QD, which, in turn, is coupled to a noninteracting conduction band. The system corresponds to an impurity Anderson model in which the conduction band has a Lorentzian density of states of width Δ2 . We solved the model using perturbation theory in the Coulomb repulsion U (PTU) up to second order and a slave-boson mean-field approximation (SBMFA). The PTU works surprisingly well near the exactly solvable limit Δ2→0 . For fixed U and large enough λ or small enough Δ2 , the Kondo peak in ρdσ(ω) splits into two peaks. This splitting can be understood in terms of weakly interacting quasiparticles. Before the splitting takes place, the universal properties of the model in the Kondo regime are lost. Using the SBMFA, simple analytical expressions for the occurrence of split peaks are obtained. For small or moderate Δ2 , the side bands of ρdσ(ω) have the form of narrow resonances that were missed in previous studies using the numerical renormalization group. This technique also has shortcomings for properly describing the split Kondo peaks. As the temperature is increased, the intensity of the split Kondo peaks decreases, but it is not completely suppressed at high temperatures.
NASA Astrophysics Data System (ADS)
Baranowski, D.
2015-12-01
Interactions between atmospheric convectively coupled Kelvin waves (CCKW), initiated over the Indian Ocean, and the diurnally varying convection over the Maritime Continent are primary interest of this presentation. Mutliscale interactions between local and propagating convection lead to substantial enhancement of the local diurnal cycle over that region. CCKW activity strongly modulates magnitude of the diurnal cycle of precipitation over the Maritime Continent, but not its temporal evolution, which maintains characteristics of a diurnal cycle. The impact is such that precipitation is highly increased during convective part of the CCKW and little suppressed during its non-convective part. Timing of the increase in diurnal cycle magnitude strongly depends on the time of the day of the CCKW approach to the Maritime Continent. It is shown that precipitation anomaly associated with CCKW is phase locked with local diurnal cycle of precipitation over the Maritime Continent and that has implications for CCKW ability to propagate across that region. The composite daily-zonal evolution of the precipitation anomaly associated with CCKW is such that it is "in-phase" with local diurnal cycle over Sumatra, Borneo and surrounding seas. This presentation is based on analysis of TRMM precipitation data and newly developed CCKW trajectories database.
Coupled calculation of the airflow interaction with elastic rod of square cross section
NASA Astrophysics Data System (ADS)
Pogudalina, S. V.; Fedorova, N. N.; Valger, S. A.
2016-10-01
The paper presents the results of numerical modeling of vibration of an elastic rod mounted normal to external flow and fixed rigidly to a substrate. The simulation is performed with ANSYS software using the technology of bidirectional coupling (2FSI). The hydrodynamic, conjugate and modal analysis have been performed. The structure of the air flow in the vicinity of the model was analyzed. The oscillations of the elastic model were revealed and the stress - strain state was obtained. The natural frequencies of the rod and corresponding vibration shapes are found. To prevent undesired vibrations of elastic structures which can lead to their destruction, the interaction of structures with external air flow must the considered. Related physical processes in which movement of the air has an impact on the behavior of deformable objects (Fluid Structure Interaction, FSI) are a key element in many engineering problems of aviation and civil engineering. Aeroelasticity phenomenon must be considered when creating modern aircraft, designing high-rise and extended buildings.
Effect of strongly coupled plasma on photoionization cross section
NASA Astrophysics Data System (ADS)
Das, Madhusmita
2014-01-01
The effect of strongly coupled plasma on the ground state photoionization cross section is studied. In the non relativistic dipole approximation, cross section is evaluated from bound-free transition matrix element. The bound and free state wave functions are obtained by solving the radial Schrodinger equation with appropriate plasma potential. We have used ion sphere potential (ISP) to incorporate the plasma effects in atomic structure calculation. This potential includes the effect of static plasma screening on nuclear charge as well as the effect of confinement due to the neighbouring ions. With ISP, the radial equation is solved using Shooting method approach for hydrogen like ions (Li+2, C+5, Al+12) and lithium like ions (C+3, O+5). The effect of strong screening and confinement is manifested as confinement resonances near the ionization threshold for both kinds of ions. The confinement resonances are very much dependent on the edge of the confining potential and die out as the plasma density is increased. Plasma effect also results in appearance of Cooper minimum in lithium like ions, which was not present in case of free lithium like ions. With increasing density the position of Cooper minimum shifts towards higher photoelectron energy. The same behaviour is also true for weakly coupled plasma where plasma effect is modelled by Debye-Huckel potential.
Effect of strongly coupled plasma on photoionization cross section
Das, Madhusmita
2014-01-15
The effect of strongly coupled plasma on the ground state photoionization cross section is studied. In the non relativistic dipole approximation, cross section is evaluated from bound-free transition matrix element. The bound and free state wave functions are obtained by solving the radial Schrodinger equation with appropriate plasma potential. We have used ion sphere potential (ISP) to incorporate the plasma effects in atomic structure calculation. This potential includes the effect of static plasma screening on nuclear charge as well as the effect of confinement due to the neighbouring ions. With ISP, the radial equation is solved using Shooting method approach for hydrogen like ions (Li{sup +2}, C{sup +5}, Al{sup +12}) and lithium like ions (C{sup +3}, O{sup +5}). The effect of strong screening and confinement is manifested as confinement resonances near the ionization threshold for both kinds of ions. The confinement resonances are very much dependent on the edge of the confining potential and die out as the plasma density is increased. Plasma effect also results in appearance of Cooper minimum in lithium like ions, which was not present in case of free lithium like ions. With increasing density the position of Cooper minimum shifts towards higher photoelectron energy. The same behaviour is also true for weakly coupled plasma where plasma effect is modelled by Debye-Huckel potential.
El Nino-southern oscillation: A coupled response to the greenhouse effect?
Sun, De-Zheng
1997-11-01
The purpose of this article to elucidate the link between the El Nino-Southern Oscillation (ENSO) and radiative forcing (of which the greenhouse effect is a major part). A unified theory for the tropical Pacific climate is developed by considering the response of the coupled ocean-atmosphere to a changing radiative forcing. The hypothesis is that both the zonal surface sea temperature (SST) gradients and ENSO are a coupled response to the strong radiative heating or the tropical warmth. Owing to ocean-atmosphere interaction, the stronger the radiative heating, the larger the zonal SST gradients. When the SST gradients exceed a critical value, however, the ocean-atmosphere interaction in the cold-tongue region is too strong for the coupled system to hold steady. Consequently, the coupled system enters an oscillatory state. These coupled dynamics are examined in a simple mathematical model whose behavior is consistent with the hypothesis. With a linear temperature profile throughout the depth of subsurface ocean, the model predicts that both the magnitude and period of the oscillation increase with increases in radiative forcing or the greenhouse effect. The increase in the magnitude of the oscillation largely comes from an enhancement of the magnitude of the cold anomalies, while the increase in the period mostly comes from a prolonged duration of the warm events. With a profile in which the lapse rate decreases with depth, the sensitivity is more moderate. The simplicity of the model prevents a quantitative simulation of the sensitivity of ENSO to increases in the greenhouse effect, but qualitatively the model results support the empirical interpretation of the prolonged duration of the 1990-1995 ENSO event. 5 refs., 7 figs.
Lefrançois, Philippe; Rockmill, Beth; Xie, Pingxing; Roeder, G. Shirleen; Snyder, Michael
2016-01-01
During meiosis, chromosomes undergo a homology search in order to locate their homolog to form stable pairs and exchange genetic material. Early in prophase, chromosomes associate in mostly non-homologous pairs, tethered only at their centromeres. This phenomenon, conserved through higher eukaryotes, is termed centromere coupling in budding yeast. Both initiation of recombination and the presence of homologs are dispensable for centromere coupling (occurring in spo11 mutants and haploids induced to undergo meiosis) but the presence of the synaptonemal complex (SC) protein Zip1 is required. The nature and mechanism of coupling have yet to be elucidated. Here we present the first pairwise analysis of centromere coupling in an effort to uncover underlying rules that may exist within these non-homologous interactions. We designed a novel chromosome conformation capture (3C)-based assay to detect all possible interactions between non-homologous yeast centromeres during early meiosis. Using this variant of 3C-qPCR, we found a size-dependent interaction pattern, in which chromosomes assort preferentially with chromosomes of similar sizes, in haploid and diploid spo11 cells, but not in a coupling-defective mutant (spo11 zip1 haploid and diploid yeast). This pattern is also observed in wild-type diploids early in meiosis but disappears as meiosis progresses and homologous chromosomes pair. We found no evidence to support the notion that ancestral centromere homology plays a role in pattern establishment in S. cerevisiae post-genome duplication. Moreover, we found a role for the meiotic bouquet in establishing the size dependence of centromere coupling, as abolishing bouquet (using the bouquet-defective spo11 ndj1 mutant) reduces it. Coupling in spo11 ndj1 rather follows telomere clustering preferences. We propose that a chromosome size preference for centromere coupling helps establish efficient homolog recognition. PMID:27768699
Loss and Periodic Coupling Effects in Dielectric Directional Couplers.
NASA Astrophysics Data System (ADS)
Youngquist, Robert Carl
1984-12-01
This dissertation is concerned with understanding the causes and effects of a new loss mechanism in dielectric directional couplers, namely dissimilar normal mode loss, as well as introducing a new class of all-fiber devices based on the periodic coupling of fiber modes. A formal introduction to coupled mode theory is developed from which directional couplers can be described by using linear propagation operators. Comparisons to the standard coupling matrix approach are made and examples are given. Theoretical arguments and experimental evidence are presented to demonstrate that the coupler modes usually have different losses. Dissimilar mode loss causes the relative phase between the light in the guides to be modified and prevents complete power transfer from occurring. Interferometers using such couplers will exhibit phase errors in their outputs and all-fiber resonators will display an asymmetry in their resonance peaks. In integrated optics lower limits are set on switching extinction ratios. It is shown that much of the analysis presented in the literature on three waveguide couplers is based on approximations that may not be valid in the regimes where the couplers are to be used. A three-waveguide coupler interferometer with dissimilar mode loss is studied and shown to have two independent outputs whose phases are environmentally insensitive to changes in coupler loss and power transfer. Uniform and periodic coupling functions are analyzed and it is shown that complete power transfer can occur when the period of the sinusoidal coupling matches the beat length between the coupled propagating waves. A birefringent fiber polarization coupler and a two-mode fiber modal coupler are demonstrated and evaluated. These compact and simple devices are used to fabricate all-fiber amplitude modulators, notch filters, in-line Mach Zehnder interferometers, and polarizers. Further applications include polarization controllers, signal processing operations such as fast word
Interacting residues in an activated state of a G protein-coupled receptor.
Lee, Yong-Hun; Naider, Fred; Becker, Jeffrey M
2006-01-27
Ste2p, the G protein-coupled receptor (GPCR) for the tridecapeptide pheromone alpha-factor of Saccharomyces cerevisiae, was used as a model GPCR to investigate the role of specific residues in the resting and activated states of the receptor. Using a series of biological and biochemical analyses of wild-type and site-directed mutant receptors, we identified Asn(205) as a potential interacting partner with the Tyr(266) residue. An N205H/Y266H double mutant showed pH-dependent functional activity, whereas the N205H receptor was non-functional and the Y266H receptor was partially active indicating that the histidine 205 and 266 residues interact in an activated state of the receptor. The introduction of N205K or Y266D mutations into the P258L/S259L constitutively active receptor suppressed the constitutive activity; in contrast, the N205K/Y266D/P258L/S259L quadruple mutant was fully constitutively active, again indicating an interaction between residues at the 205 and 206 positions in the receptor-active state. To further test this interaction, we introduced the N205C/Y266C, F204C/Y266C, and N205C/A265C double mutations into wild-type and P258L/S259L constitutively active receptors. After trypsin digestion, we found that a disulfide-cross-linked product, with the molecular weight expected for a receptor fragment with a cross-link between N205C and Y266C, formed only in the N205C/Y266C constitutively activated receptor. This study represents the first experimental demonstration of an interaction between specific residues in an active state, but not the resting state, of Ste2p. The information gained from this study should contribute to an understanding of the conformational differences between resting and active states in GPCRs. PMID:16314417
Effects of hydrodynamic interactions in bacterial swimming.
NASA Astrophysics Data System (ADS)
Chattopadhyay, Suddhashil; Lun Wu, Xiao
2008-03-01
The lack of precise experimental data has prevented the investigation of the effects of long range hydrodynamic interactions in bacterial swimming. We perform measurements on various strains of bacteria with the aid of optical tweezers to shed light on this aspect of bacterial motility. Geometrical parameters recorded by fluorescence microscopy are used with theories which model flagella propulsion (Resistive force theory & Lighthill's formulation which includes long range interactions). Comparison of the predictions of these theories with experimental data, observed directly from swimming bacterium, led to the conclusion that while long range inetractions were important for single polar flagellated strains (Vibrio Alginolyticus & Caulobacter Crescentus), local force theory was adequate to describe the swimming of multi-flagellated Esherichia Coli. We performed additional measurements on E. Coli minicells (miniature cells with single polar flagellum) to try and determine the cause of this apparent effect of shielding of long range interactions in multiple flagellated bacteria.
NASA Astrophysics Data System (ADS)
Xin, Xiaoge; Xue, Wei; Zhang, Minghua; Li, Huimin; Zhang, Tao; Zhang, Jie
2015-02-01
The chaotic atmospheric circulations and the ocean-atmosphere coupling may both cause variations in the North Atlantic Oscillation (NAO). This study uses an interactive ensemble (IE) coupled model to study the contribution of the atmospheric noise and coupling to the monthly variability of the NAO. In the IE model, seven atmospheric general circulation model (AGCM) realizations with different initial states are coupled with a single realization of the land, ocean and ice component models. The chaotic noise from the atmosphere at the air-sea interface is therefore reduced. The time variances of monthly NAO index in the ensemble AGCM mean of the IE model is found to be about 20.1 % of that in the SC model. Therefore, more than 79.9 % of the simulated monthly variability of NAO is caused by atmospheric noise. The coupling between sea surface temperature (SST) and NAO is only found in regions south of about 40°N in the North Atlantic Ocean. The IE strategy highlighted the interaction between the NAO and the SST in the region (28°-38°N, 20°W-50°W) to the southeast of the Gulf Stream extension. While the ocean-atmosphere coupling explains <1/5th of the NAO variability in the IE model, it shows slightly larger persistence than the SC model, consistent with the hypothesis of a slower mode of variability from ocean-atmosphere coupling that has larger predictability than the variability driven by the atmosphere.
Hey Mr. Sandman: dyadic effects of anxiety, depressive symptoms and sleep among married couples.
Revenson, Tracey A; Marín-Chollom, Amanda M; Rundle, Andrew G; Wisnivesky, Juan; Neugut, Alfred I
2016-04-01
This study examined associations among anxiety, depressive symptoms, and sleep duration in a sample of middle-aged couples using the actor-partner interaction model with dyadic data. Self-report measures were completed independently by both partners as part of the health histories obtained during their annual preventive medical examinations in 2011 and 2012. Results showed that husbands' anxiety and depressive symptoms had a stronger effect on their wives' anxiety and depression than the other way around, but this was not moderated by one's own sleep duration. For both wives and husbands, higher levels of depressive symptoms and anxiety predicted shorter sleep duration for their partner 1 year later, although the effect of husbands' mental health on their wives' was again stronger. The findings suggest that sleep problems might better be treated as a couple-level phenomenon than an individual one, particularly for women. PMID:26546242
Spinning boson stars and Kerr black holes with scalar hair: The effect of self-interactions
NASA Astrophysics Data System (ADS)
Herdeiro, Carlos A. R.; Radu, Eugen; Rúnarsson, Helgi F.
2016-05-01
Self-interacting boson stars (BSs) have been shown to alleviate the astrophysically low maximal mass of their nonself-interacting counterparts. We report some physical features of spinning self-interacting BSs, namely their compactness, the occurrence of ergo-regions and the scalar field profiles, for a sample of values of the coupling parameter. The results agree with the general picture that these BSs are comparatively less compact than the nonself-interacting ones. We also briefly discuss the effect of scalar self-interactions on the properties of Kerr black holes with scalar hair.
Chen, Hung-Cheng; Hsu, Chao-Ping
2005-12-29
To calculate electronic couplings for photoinduced electron transfer (ET) reactions, we propose and test the use of ab initio quantum chemistry calculation for excited states with the generalized Mulliken-Hush (GMH) method. Configuration-interaction singles (CIS) is proposed to model the locally excited (LE) and charge-transfer (CT) states. When the CT state couples with other high lying LE states, affecting coupling values, the image charge approximation (ICA), as a simple solvent model, can lower the energy of the CT state and decouple the undesired high-lying local excitations. We found that coupling strength is weakly dependent on many details of the solvent model, indicating the validity of the Condon approximation. Therefore, a trustworthy value can be obtained via this CIS-GMH scheme, with ICA used as a tool to improve and monitor the quality of the results. Systems we tested included a series of rigid, sigma-linked donor-bridge-acceptor compounds where "through-bond" coupling has been previously investigated, and a pair of molecules where "through-space" coupling was experimentally demonstrated. The calculated results agree well with experimentally inferred values in the coupling magnitudes (for both systems studied) and in the exponential distance dependence (for the through-bond series). Our results indicate that this new scheme can properly account for ET coupling arising from both through-bond and through-space mechanisms.
Reduction of FCCI effects in lanthanide-iron diffusion couples by doping with palladium
NASA Astrophysics Data System (ADS)
Egeland, G. W.; Mariani, R. D.; Hartmann, T.; Porter, D. L.; Hayes, S. L.; Kennedy, J. R.
2013-09-01
Fast-reactor metallic fuels produce lanthanide fission products which have been shown to diffuse to the fuel periphery. Lanthanides interacting with the cladding is one cause of fuel-cladding chemical interaction. To test the viability of reducing the interaction by pinning these lanthanides, palladium was chosen as a fuel dopant based on the lanthanide-palladium intermetallic thermodynamic stability and fuel compatibility. Three lanthanides were tested, neodymium, cerium, and praseodymium, along with their 1:1 palladium compounds, against iron using diffusion couples. These experiments show the direct contact effect on iron of each lanthanide and its respective palladium compound at temperatures from 580 °C to 700 °C for 100 h.
Simple Coupling of Reactor Physics Effects and Uncertain Nuances
2012-08-27
The "Simple Coupling of Reactor Physics Effects and Uncertain Nuances" (SCORPEUN) code is a simple r-z 1-group neutron diffusion code where each r-mesh is coupled to a single-flow-channel model that represents all flow-channels in that r-mesh. This 1-D model assesses q=m*Cp*deletaT for each z-mesh in that channel. This flow channel model is then coupled to a simple 1-D heat conduction model for ascertaining the peak center-line fuel temperature in a hypothetical pin assigned to thatmore » flow channel. The code has property lookup capability for water, Na, Zirc, HT9, metalic fuel, oxide fuel, etc. It has linear interpolation features for micro-scopic cross-sections with respect to coolant density and fuel temperature. ***This last feature has not been fully tested and may need development***. The interpolated microscopic cross-sections are then combined (using the water density from the T/H calculation) to generate macroscopic diffusion coefficient, removal cross-section and nu-sigmaF for each r-z mesh of the neutron diffusion code.« less
NASA Astrophysics Data System (ADS)
Cerpa, Nestor; Hassani, Riad; Gerbault, Muriel
2014-05-01
A large variety of geodynamical problems can be viewed as a solid/fluid interaction problem coupling two bodies with different physics. In particular the lithosphere/asthenosphere mechanical interaction in subduction zones belongs to this kind of problem, where the solid lithosphere is embedded in the asthenospheric viscous fluid. In many fields (Industry, Civil Engineering,etc.), in which deformations of solid and fluid are "small", numerical modelers consider the exact discretization of both domains and fit as well as possible the shape of the interface between the two domains, solving the discretized physic problems by the Finite Element Method (FEM). Although, in a context of subduction, the lithosphere is submitted to large deformation, and can evolve into a complex geometry, thus leading to important deformation of the surrounding asthenosphere. To alleviate the precise meshing of complex geometries, numerical modelers have developed non-matching interface methods called Fictitious Domain Methods (FDM). The main idea of these methods is to extend the initial problem to a bigger (and simpler) domain. In our version of FDM, we determine the forces at the immersed solid boundary required to minimize (at the least square sense) the difference between fluid and solid velocities at this interface. This method is first-order accurate and the stability depends on the ratio between the fluid background mesh size and the interface discretization. We present the formulation and provide benchmarks and examples showing the potential of the method : 1) A comparison with an analytical solution of a viscous flow around a rigid body. 2) An experiment of a rigid sphere sinking in a viscous fluid (in two and three dimensional cases). 3) A comparison with an analog subduction experiment. Another presentation aims at describing the geodynamical application of this method to Andean subduction dynamics, studying cyclic slab folding on the 660 km discontinuity, and its relationship
A coupled general circulation model for the Late Jurassic including fully interactive carbon cycling
NASA Astrophysics Data System (ADS)
Williams, J.; Valdes, P. J.; Leith, T. L.; Sagoo, N.
2011-12-01
The climatology of a coupled atmosphere - ocean (including sea ice) general circulation model for the Late Jurassic epoch (Kimmeridgian stage) is presented. The simulation framework used is the FAMOUS climate model [Jones et al, Climate Dynamics 25, 189-204 (2005)], which is a reduced resolution configuration of the UK Met Office model HadCM3 [Pope et al, Climate Dynamics 16, 123-46 (2000)]. In order to enable computation of carbon fluxes through the Earth System, fully interactive terrestrial and oceanic carbon cycle modules are added to FAMOUS. These include temporally evolving vegetation on land and populations of zooplankton, phytoplankton and nitrogenous nutrients in the ocean. The Kimmeridgian was a time of significantly enhanced carbon dioxide concentrations in the atmosphere (roughly four times preindustrial) and as such is a useful test bed for "paleocalibration" of a future climate perturbed by anthropogenic emissions of greenhouse gases [Barron et al, Paleoceanography 10 (5) 953-962 (1995) for example]. From a geological perspective, the Kimmeridgian was also a time of significant laying down of hydrocarbon reserves (particularly in the North Sea) and thus the inclusion of a fully interactive carbon cycle in FAMOUS enables the study of the dysoxic (low oxygen) and circulatory conditions relevant to their formation and preservation. The parameter space of both the terrestrial and oceanic carbon cycles was explored using the Latin Hypercube method [Mckay, Proceedings of the 24th conference on winter simulation, ACM Press, Arlington, Virginia, 57-564 (1992)], which enables efficient yet rigorous sampling of multiple covarying parameters. These parameters were validated using present day observations of meteorological, vegetative and biological parameters since the data available for the Jurassic itself is relatively scarce. To remove subjective bias in the validation process, the "Arcsine Mielke" skill score was used [Watterson, Int. J. Climatology, 16, 379
Hansen, M; Bentz, J; Baucom, A; Gregoret, L
1998-01-01
Gaining functional information about a novel protein is a universal problem in biomedical research. With the explosive growth of the protein sequence and structural databases, it is becoming increasingly common for researchers to attempt to build a three-dimensional model of their protein of interest in order to gain information about its structure and interactions with other molecules. The two most reliable methods for predicting the structure of a protein are homology modeling, in which the novel sequence is modeled on the known three-dimensional structure of a related protein, and fold recognition (threading), where the sequence is scored against a library of fold models, and the highest scoring model is selected. The sequence alignment to a known structure can be ambiguous, and human intervention is often required to optimize the model. We describe an interactive model building and assessment tool in which a sequence alignment editor is dynamically coupled to a molecular graphics display. By means of a set of assessment tools, the user may optimize his or her alignment to satisfy the known heuristics of protein structure. Adjustments to the sequence alignment made by the user are reflected in the displayed model by color and other visual cues. For instance, residues are colored by hydrophobicity in both the three-dimensional model and in the sequence alignment. This aids the user in identifying undesirable buried polar residues. Several different evaluation metrics may be selected including residue conservation, residue properties, and visualization of predicted secondary structure. These characteristics may be mapped to the model both singly and in combination. DINAMO is a Java-based tool that may be run either over the web or installed locally. Its modular architecture also allows Java-literate users to add plug-ins of their own design.
Effective Interactions from No Core Shell Model
Dikmen, E.; Lisetskiy, A. F.; Barrett, B. R.; Navratil, P.; Vary, J. P.
2008-11-11
We construct the many-body effective Hamiltonian for pf-shell by carrying out 2({Dirac_h}/2{pi}){omega}. NCSM calculations at the 2-body cluster level. We demonstrate how the effective Hamiltonian derived from realistic nucleon-nucleon (NN) potentials for the 2({Dirac_h}/2{pi}){omega} NCSM space should be modified to properly account for the many-body correlations produced by truncating to the major pf-shell. We obtain two-body effective interactions for the pf-shell by using direct projection and use them to reproduce the results of large scale NCSM for other light Ca isotopes.
Noisy contact interactions of multi-layer mechanical structures coupled by boundary conditions
NASA Astrophysics Data System (ADS)
Awrejcewicz, J.; Krysko, V. A., Jr.; Yakovleva, T. V.; Krysko, V. A.
2016-05-01
In this work mathematical models of temporal part of chaos at chosen spatial locations of a plate locally reinforced by ribs taking into account an interplay of their interactions are derived and studied numerically for the most relevant dynamical parameters. In addition, an influence of the additive external noise on chaotic vibrations of multi-layer beam-plate structures coupled only by boundary conditions is investigated. We illustrate and discuss novel nonlinear phenomena of the temporal regular and chaotic contact/no-contact dynamics with the help of Morlet wavelets and Fourier analysis. We show how the additive white noise cancels deterministic chaos close to the boundary of chaotic region in the space of parameters, and we present windows of on/off switching of the frequencies during the contact dynamics between structural members. In order to solve the mentioned design type nonlinear problem we apply methods of qualitative theory of differential equations, the Bubnov-Galerkin method in higher approximations, the Runge-Kutta methods of 4th, 6th and 8th order, as well as the computation and analysis of the largest Lyapunov exponent (Benettin's and Wolf's algorithms are used). The agreement of outcomes of all applied qualitatively different numerical approaches validate our simulation results. In particular, we have illustrated that the Fourier analysis of the studied mechanical structures may yield erroneous results, and hence the wavelet-based analysis is used to investigate chaotic dynamics in the system parameter space.
Sala, Pia; Pötz, Sandra; Brunner, Martina; Trötzmüller, Martin; Fauland, Alexander; Triebl, Alexander; Hartler, Jürgen; Lankmayr, Ernst; Köfeler, Harald C
2015-04-14
A novel liquid chromatography-mass spectrometry (LC-MS) approach for analysis of oxidized phosphatidylcholines by an Orbitrap Fourier Transform mass spectrometer in positive electrospray ionization (ESI) coupled to hydrophilic interaction liquid chromatography (HILIC) was developed. This method depends on three selectivity criteria for separation and identification: retention time, exact mass at a resolution of 100,000 and collision induced dissociation (CID) fragment spectra in a linear ion trap. The process of chromatography development showed the best separation properties with a silica-based Kinetex column. This type of chromatography was able to separate all major lipid classes expected in mammalian samples, yielding increased sensitivity of oxidized phosphatidylcholines over reversed phase chromatography. Identification of molecular species was achieved by exact mass on intact molecular ions and CID tandem mass spectra containing characteristic fragments. Due to a lack of commercially available standards, method development was performed with copper induced oxidation products of palmitoyl-arachidonoyl-phosphatidylcholine, which resulted in a plethora of lipid species oxidized at the arachidonoyl moiety. Validation of the method was done with copper oxidized human low-density lipoprotein (LDL) prepared by ultracentrifugation. In these LDL samples we could identify 46 oxidized molecular phosphatidylcholine species out of 99 possible candidates.
Flow Coupling Effects in Jet-in-Crossflow Flowfields
NASA Technical Reports Server (NTRS)
Bain, D. B.; Smith, C. E.; Liscinsky, D. S.; Holdeman, J. D.
1996-01-01
The combustor designer is typically required to design liner orifices that effectively mix air jets with crossflow effluent. CFD combustor analysis is typically used in the design process; however the jets are usually assumed to enter the combustor with a uniform velocity and turbulence profile. The jet-mainstream flow coupling is usually neglected because of the computational expense. This CFD study was performed to understand the effect of jet-mainstream flow coupling, and to assess the accuracy of jet boundary conditions that are commonly used in combustor internal calculations. A case representative of a plenum-fed quick-mix section of a Rich Burn/Quick Mix/Lean Burn combustor (i.e. a jet-mainstream mass-flow ratio of about 3 and a jet-mainstream momentum-flux ratio of about 30) was investigated. This case showed that the jet velocity entering the combustor was very non-uniform, with a low normal velocity at the leading edge of the orifice and a high normal velocity at the trailing edge of the orifice. Three different combustor-only cases were analyzed with uniform inlet jet profile. None of the cases matched the plenum-fed calculations. To assess liner thickness effects, a thin-walled case was also analyzed. The CFD analysis showed the thin-walled jets had more penetration than the thick-walled jets.
The effect of rock-water interaction on permeability
Lin, Wunan; Roberts, J.J.; Glassley, W.; Ruddle, D.
1995-06-01
Current investigations for managing high-level nuclear wastes focus on studying deep geologic repositories. The Yucca Mountain Site Characterization Project of the US Department of Energy conducts studies on Yucca Mountain, Nevada, to determine its suitability as a potential high-level nuclear waste repository. The potential host rock in Yucca Mountain is a layer of devitrified Topopah Spring tuff that is densely welded, fractured, and lithophysae-poor. The suitability of a potential nuclear waste repository site depends on, among other factors, how the near-field environment affects the integrity of waste package materials and the transport of radioactive nuclides away from waste packages. Model calculations are needed to predict the near-field environment for the entire life-span of a repository. Radioactive decay heat from nuclear waste packages is likely to create coupled thermal-mechanical-hydrological-chemical (TMHC) processes in the near field of a repository. The coupled TMHC processes must be understood so they can be incorporated in the model calculations. One of the coupled TMHC processes is the effect of the rock-water interaction (a chemical-mineralogical process) on the fluid flow in the rock mass (a hydrological process).
Zheng, Jieru; Kang, Youn K; Therien, Michael J; Beratan, David N
2005-08-17
Donor-acceptor interactions were investigated in a series of unusually rigid, cofacially compressed pi-stacked porphyrin-bridge-quinone systems. The two-state generalized Mulliken-Hush (GMH) approach was used to compute the coupling matrix elements. The theoretical coupling values evaluated with the GMH method were obtained from configuration interaction calculations using the INDO/S method. The results of this analysis are consistent with the comparatively soft distance dependences observed for both the charge separation and charge recombination reactions. Theoretical studies of model structures indicate that the phenyl units dominate the mediation of the donor-acceptor coupling and that the relatively weak exponential decay of rate with distance arises from the compression of this pi-electron stack.
Effect of particle interactions on thermoremanent magnetization
NASA Astrophysics Data System (ADS)
Newell, A. J.; Niemerg, M.; Bates, D.
2013-12-01
Paleomagnetism has a dizzying array of protocols for determining the strength of the Earth's magnetic field in the past from measurements of the magnetic memory in rocks. Some, such as variants of the Thellier-Thellier method, try to isolate the signal from an "ideal" fraction of magnetic minerals, discarding the contribution of "non-ideal" minerals; others, like the multi-specimen method, try to glean useful information from all of the minerals. The "ideal" remanence carriers behave like single-domain (SD) magnets with uniaxial anisotropy, and their behavior is predicted by Louis Néel's theory of thermoremanent magnetization (TRM). Non-ideal carriers are not at all well understood, but every paleointensity method relies on assumptions about their nature to either remove their signal or make use of it. One way to explore the boundary between ideal and non-ideal is to look at the behavior of SD magnets as they are brought increasingly close together, thus increasing the strength of the magnetostatic coupling between them. Magnetostatic coupling greatly increases the complexity of such a system. Instead of just two stable states, many must be found. Instead of one energy barrier, there is a network of connections between stable states over energy barriers. Instead of one rate for the relaxation of a system towards equilibrium, there are several. It is particularly difficult to find the transition states at the top of the energy barriers. We have developed software that does all of the above. A method from algebraic geometry called homotopy continuation is used to find all stable states and transition states. The software can track changes in these states with magnetic field, temperature, or other external variables. We use it to model TRM acquisition in small systems of interacting particles, and examine its behavior under various paleointensity tests.
Baig, M. H.; Ahmad, K.; Hasan, Q.; Khan, M. K. A.; Rao, N. S.; Kamal, M. A.; Choi, I.
2015-01-01
Glucagon receptor (GCGR) is a secretin-like (class B) family of G-protein coupled receptors (GPCRs) in humans that plays an important role in elevating the glucose concentration in blood and has thus become one of the promising therapeutic targets for treatment of type 2 diabetes mellitus. GCGR based inhibitors for the treatment of type 2 diabetes are either glucagon neutralizers or small molecular antagonists. Management of diabetes without any side effects is still a challenge to the medical system, and the search for a new and effective natural GCGR antagonist is an important area for the treatment of type 2 diabetes. In the present study, a number of natural compounds containing antidiabetic properties were selected from the literature and their binding potential against GCGR was determined using molecular docking and other in silico approaches. Among all selected natural compounds, curcumin was found to be the most effective compound against GCGR followed by amorfrutin 1 and 4-hydroxyderricin. These compounds were rescored to confirm the accuracy of binding using another scoring function (x-score). The final conclusions were drawn based on the results obtained from the GOLD and x-score. Further experiments were conducted to identify the atomic level interactions of selected compounds with GCGR. PMID:26236379
Spin-orbital and spin Kondo effects in parallel coupled quantum dots
NASA Astrophysics Data System (ADS)
Krychowski, D.; Lipiński, S.
2016-02-01
Strong electron correlations and interference effects are discussed in parallel-coupled single-level or orbitally doubly degenerate quantum dots. The finite-U mean-field slave boson approach is used to study many-body effects. The analysis is carried out in a wide range of parameter space including both atomic-like and molecular-like Kondo regimes and taking into account various perturbations, like interdot tunneling, interdot interaction, mixing of the electrode channels, and exchange interaction. We also discuss the influence of singularities of electronic structure and the impact of polarization of electrodes. Special attention is paid to potential spintronic applications of these systems showing how current polarization can be controlled by adjusting interference conditions and correlations by gate voltage. Simple proposals of double dot spin valve and bipolar electrically tunable spin filter are presented.
Long-range magnetic interactions and proximity effects in an amorphous exchange-spring magnet.
Magnus, F; Brooks-Bartlett, M E; Moubah, R; Procter, R A; Andersson, G; Hase, T P A; Banks, S T; Hjörvarsson, B
2016-01-01
Low-dimensional magnetic heterostructures are a key element of spintronics, where magnetic interactions between different materials often define the functionality of devices. Although some interlayer exchange coupling mechanisms are by now well established, the possibility of direct exchange coupling via proximity-induced magnetization through non-magnetic layers is typically ignored due to the presumed short range of such proximity effects. Here we show that magnetic order can be induced throughout a 40-nm-thick amorphous paramagnetic layer through proximity to ferromagnets, mediating both exchange-spring magnet behaviour and exchange bias. Furthermore, Monte Carlo simulations show that nearest-neighbour magnetic interactions fall short in describing the observed effects and long-range magnetic interactions are needed to capture the extent of the induced magnetization. The results highlight the importance of considering the range of interactions in low-dimensional heterostructures and how magnetic proximity effects can be used to obtain new functionality. PMID:27291298
Long-range magnetic interactions and proximity effects in an amorphous exchange-spring magnet
Magnus, F.; Brooks-Bartlett, M. E.; Moubah, R.; Procter, R. A.; Andersson, G.; Hase, T. P. A.; Banks, S. T.; Hjörvarsson, B.
2016-01-01
Low-dimensional magnetic heterostructures are a key element of spintronics, where magnetic interactions between different materials often define the functionality of devices. Although some interlayer exchange coupling mechanisms are by now well established, the possibility of direct exchange coupling via proximity-induced magnetization through non-magnetic layers is typically ignored due to the presumed short range of such proximity effects. Here we show that magnetic order can be induced throughout a 40-nm-thick amorphous paramagnetic layer through proximity to ferromagnets, mediating both exchange-spring magnet behaviour and exchange bias. Furthermore, Monte Carlo simulations show that nearest-neighbour magnetic interactions fall short in describing the observed effects and long-range magnetic interactions are needed to capture the extent of the induced magnetization. The results highlight the importance of considering the range of interactions in low-dimensional heterostructures and how magnetic proximity effects can be used to obtain new functionality. PMID:27291298
[Coupling effects of water and fertilizer on the biomass of Populus tomentosa seedlings].
Dong, Wen-yi; Zhao, Yan; Zhang, Zhi-yi; Li, Ji-yue; Nie, Li-shui
2010-09-01
Water and fertilizer are the two main factors promoting the fast growth and high-yielding of Populus tomentosa, and thus, to study their coupling effects on the biomass of P. tomentosa seedlings has important practical significance. Taking the P. tomentosa clone 87 seedlings as test materials, a pot experiment with rotary combination design of square regression of three factors with five levels was conducted in the nursery of Beijing Forestry University from March to October 2008 to study the coupling effects of water, fertilizer N, and fertilizer P on the biomass of the seedlings, and a related regressive mathematical model was established. The results showed that water was the main factor affecting the biomass of P. tomentosa seedlings, followed by fertilizer N, and fertilizer P. With the increasing input of the three factors, the biomass of the seedlings increased, but when the input was beyond a certain level, the biomass began to decrease. There was a significant positive interactive effect between water and fertilizer N, but a less interactive effect between fertilizer N and fertilizer P and between water and fertilizer P. In our case, the optimal combination of water and fertilizer was 73.37% of field capacity + 4.14 g x plant(-1) of N fertilization + 1.41 g x plant(-1) of P fertilization, under which, the biomass of P. tomentosa seedlings achieved 68.30 g x plant(-1).
Chang Yue; Sun, C. P.
2011-05-15
We study a hybrid nanomechanical system coupled to a spin ensemble as a quantum simulator to favor a quantum interference effect, electromagnetically induced transparency (EIT). This system consists of two nanomechanical resonators (NAMRs), each of which is coupled to a nuclear spin ensemble, and can be regarded as a crucial element in the quantum network of NAMR arrays coupled to spin ensembles. Here, the nuclear spin ensembles behave as a long-lived transducer to store and transfer the NAMRs' quantum information. This system shows the analog of the EIT effect under the driving of a probe microwave field. The double EIT phenomenon emerges in the large-N (the number of nuclei) limit within the low excitation approximation, because the interactions between the spin ensemble and the two NAMRs are reduced to the coupling of three harmonic oscillators. Furthermore, the group velocity is reduced in the two absorption windows.
Collider effects of unparticle interactions in multiphoton signals
Aliev, T. M.; Frank, Mariana; Turan, Ismail
2009-12-01
A new model of physics, with a hidden conformal sector which manifests itself as an unparticle coupling to standard model particles effectively through higher dimensional operators, predicts strong collider signals due to unparticle self-interactions. We perform a complete analysis of the most spectacular of these signals at the hadron collider, pp(p){yields}{gamma}{gamma}{gamma}{gamma} and {gamma}{gamma}gg. These processes can go through the three-point unparticle self-interactions as well as through some s and t channel diagrams with one and/or two unparticle exchanges. We study the contributions of individual diagrams classified with respect to the number of unparticle exchanges and discuss their effect on the cross sections at the Tevatron and the LHC. We also restrict the Tevatron bound on the unknown coefficient of the three-point unparticle correlator. With the availability of data from the Tevatron, and the advent of the data emerging from the LHC, these interactions can provide a clear and strong indication of unparticle physics and distinguish this model from other beyond the standard model scenarios.
NASA Astrophysics Data System (ADS)
Markun, B.; Žumer, S.
2006-03-01
A theoretical study of the Casimir interaction in smectic-A systems, considering fluctuations of both types of smectic ordering—positional and orientational—including the coupling between them, is presented. Two model systems with plan-parallel geometry are studied: homeotropic cell and free-standing film. At large thicknesses of the system the behavior of the Casimir force is found to be primarily determined by positional fluctuations, whereas at small thicknesses also the orientational degrees of freedom greatly contribute to the interaction. The influence of different coupling strengths between orientational and positional order is presented. The dependence of the Casimir force on the director anchoring and surface-tension parameters is studied. The possibilities of experimental detection of the interaction are discussed.
Alcohol effects on drug-nutrient interactions.
Seitz, H K
1985-01-01
The interaction of ethanol with drugs and xenobiotics is complex because ethanol can affect any of the following steps; absorption, plasma protein binding, hepatic blood flow, distribution, hepatic uptake of drugs, and phase I and II hepatic metabolism. The ingestion of ethanol can lead to malabsorption of a variety of nutrients and can modify the absorption of various drugs. High concentrations of ethanol in conjunction with aspirin causes gastric mucosal damage. The principal effect of acute ethanol ingestion on drug metabolism is inhibition of microsomal drug metabolism. The synergistic effects of ethanol on central nervous system depressants can be explained by this mechanism. In contrast, chronic ethanol consumption increases mixed function oxidation and drug metabolism. The cross tolerance between ethanol and sedatives in chronic alcoholics may be due to this effect of alcohol. In addition, enhanced production of hepatotoxic products from certain drugs and xenobiotics and an increased activation of procarcinogens to carcinogens can result from this microsomal induction. The increased susceptibility to hepatotoxins and the enhanced carcinogenesis in the alcoholic may be explained by this fact. Other effects of the interaction between drugs and ethanol are the result of changes in organ susceptibility, best demonstrated for the central nervous system. Subsequently, the presence of liver disease has a great effect on drug metabolism in alcoholics.
Exchange bias training effect in coupled all ferromagnetic bilayer structures.
Binek, Ch; Polisetty, S; He, Xi; Berger, A
2006-02-17
Exchange coupled bilayers of soft and hard ferromagnetic thin films show remarkable analogies to conventional antiferromagnetic/ferromagnetic exchange bias heterostructures. Not only do all these ferromagnetic bilayers exhibit a tunable exchange bias effect, they also show a distinct training behavior upon cycling the soft layer through consecutive hysteresis loops. In contrast with conventional exchange bias systems, such all ferromagnetic bilayer structures allow the observation of training induced changes in the bias-setting hardmagnetic layer by means of simple magnetometry. Our experiments show unambiguously that the exchange bias training effect is driven by deviations from equilibrium in the pinning layer. A comparison of our experimental data with predictions from a theory based upon triggered relaxation phenomena shows excellent agreement.
Numerical Modeling of Coupled Groundwater and Surface Water Interactions in an Urban Setting
Rihani, J F; Maxwell, R M
2007-09-26
The Dominguez Channel Watershed (DCW), located in the southern portion of Los Angeles County (Figure A.1), drains about 345 square miles into the Los Angeles Harbor. The cities and jurisdictions in DCW are shown in Figure A.2. The largest of these include the cities of Los Angeles, Carson, and Torrance. This watershed is unique in that 93% of its land area is highly developed (i.e. urbanized). The watershed boundaries are defined by a complex network of storm drains and flood control channels, rather than being defined by natural topography. Table (1) shows a summary of different land uses in the Dominguez Channel Watershed (MEC, 2004). The Dominguez Watershed has the highest impervious area of all watersheds in the Los Angeles region. The more impervious the surface, the more runoff is generated during a storm. Storm water runoff can carry previously accumulated contaminants and transport them into receiving water systems. Point sources such as industrial wastewater and municipal sewage as well as urban runoff from commercial, residential, and industrial areas are all recognized as contributors to water quality degradation at DWC. Section 303(d) of the 1972 Federal Clean Water Act (CWA) requires states to identify and report all waters not meeting water quality standards and to develop action plans to pursue the water quality objectives. These plans specify the maximum amount of a given pollutant that the water body of concern can receive and still meet water quality standards. Such plans are called Total Maximum Daily Loads (TMDLs). TMDLs also specify allocations of pollutant loadings to point and non-point sources taking into account natural background pollutant levels. This demonstrates the importance of utilizing scientific tools, such as flow and transport models, to identify contaminant sources, understand integrated flow paths, and assess the effectiveness of water quality management strategies. Since overland flow is a very important component of the water
Anisotropic Paramagnetic Meissner Effect by Spin-Orbit Coupling
NASA Astrophysics Data System (ADS)
Espedal, Camilla; Yokoyama, Takehito; Linder, Jacob
2016-03-01
Conventional s -wave superconductors repel an external magnetic field. However, a recent experiment [A. Di Bernardo et al., Phys. Rev. X 5, 041021 (2015)] has tailored the electromagnetic response of superconducting correlations via adjacent magnetic materials. We consider another route of altering the Meissner effect where spin-orbit interactions induce an anisotropic Meissner response that changes sign depending on the field orientation. The tunable electromagnetic response opens new paths in the utilization of hybrid systems comprising magnets and superconductors.
Stress Effects on Multiple Memory System Interactions
Ness, Deborah; Calabrese, Pasquale
2016-01-01
Extensive behavioural, pharmacological, and neurological research reports stress effects on mammalian memory processes. While stress effects on memory quantity have been known for decades, the influence of stress on multiple memory systems and their distinct contributions to the learning process have only recently been described. In this paper, after summarizing the fundamental biological aspects of stress/emotional arousal and recapitulating functionally and anatomically distinct memory systems, we review recent animal and human studies exploring the effects of stress on multiple memory systems. Apart from discussing the interaction between distinct memory systems in stressful situations, we will also outline the fundamental role of the amygdala in mediating such stress effects. Additionally, based on the methods applied in the herein discussed studies, we will discuss how memory translates into behaviour. PMID:27034845
Contamination Effects Due to Space Environmental Interactions
NASA Technical Reports Server (NTRS)
Chen, Philip T.; Paquin, Krista C. (Technical Monitor)
2001-01-01
Molecular and particulate contaminants are commonly generated from the orbital spacecraft operations that are under the influence of the space environment. Once generated, these contaminants may attach to the surfaces of the spacecraft or may remain in the vicinity of the spacecraft. In the event these contaminants come to rest on the surfaces of the spacecraft or situated in the line-of-sight of the observation path, they will create various degrees of contamination effect which may cause undesirable effects for normal spacecraft operations, There will be circumstances in which the spacecraft may be subjected to special space environment due to operational conditions. Interactions between contaminants and special space environment may alter or greatly increase the contamination effect due to the synergistic effect. This paper will address the various types of contamination generation on orbit, the general effects of the contamination on spacecraft systems, and the typical impacts on the spacecraft operations due to the contamination effect. In addition, this paper will explain the contamination effect induced by the space environment and will discuss the intensified contamination effect resulting from the synergistic effect with the special space environment.
Xiang Wenchang
2009-01-01
The analytic form of the asymptotic behavior of the S matrix in the saturation regime including the running coupling is obtained. To get this result, we solve the Balitsky and Kovchegov-Weigert evolution equations in the saturation regime, which include running coupling corrections. We study also the effect of rare fluctuations on top of the running coupling. We find that the rare fluctuations are less important in the running coupling case as compared to the fixed coupling case.
Pipeline coating impedance effects on powerline fault current coupling
Dabkowski, J.
1989-12-01
Prior research leading to the development of predictive electromagnetic coupling computer codes has shown that the coating conductance is the principal factor in determining the response of a pipeline to magnetic induction from an overhead power transmission line. Under power line fault conditions, a high voltage may stress the coating causing a significant change in its conductance, and hence, the coupling response. Based upon laboratory experimentation and analysis, a model has been developed which allows prediction of the modified coating characteristics when subjected to high voltage during fault situations. Another program objective was the investigation of a method to determine the high voltage behavior of an existing coating from low voltage in situ field measurements. Such a method appeared conceptually feasible for non-porous coatings whose conductance is primarily a result of current leakage through existing holidays. However, limited testing has shown that difficulties in determining the steel-electrolyte capacitance limit the application of the method Methods for field measurement of the pipeline coating conductance were also studied for both dc ad ac signal excitation. Ac techniques offer the advantage that cathodic protection current interruption is not required, thus eliminating depolarization effects. However, ac field measurement techniques need additional refinement before these methods can be generally applied. 53 figs.
Matrix effects in inductively coupled plasma mass spectrometry
Chen, Xiaoshan
1995-07-07
The inductively coupled plasma is an electrodeless discharge in a gas (usually Ar) at atmospheric pressure. Radio frequency energy generated by a RF power source is inductively coupled to the plasma gas through a water cooled load coil. In ICP-MS the {open_quotes}Fassel{close_quotes} TAX quartz torch commonly used in emission is mounted horizontally. The sample aerosol is introduced into the central flow, where the gas kinetic temperature is about 5000 K. The aerosol is vaporized, atomized, excited and ionized in the plasma, and the ions are subsequently extracted through two metal apertures (sampler and skimmer) into the mass spectrometer. In ICP-MS, the matrix effects, or non-spectroscopic interferences, can be defined as the type of interferences caused by dissolved concomitant salt ions in the solution. Matrix effects can be divided into two categories: (1) signal drift due to the deposition of solids on the sampling apertures; and/or (2) signal suppression or enhancement by the presence of the dissolved salts. The first category is now reasonably understood. The dissolved salts, especially refractory oxides, tend to deposit on the cool tip of the sampling cone. The clogging of the orifices reduces the ion flow into the ICP-MS, lowers the pressure in the first stage of ICP-MS, and enhances the level of metal oxide ions. Because the extent of the clogging increases with the time, the signal drifts down. Even at the very early stage of the development of ICP-MS, matrix effects had been observed. Houk et al. found out that the ICP-MS was not tolerant to solutions containing significant amounts of dissolved solids.
RCS jet-flow field interaction effects on the aerodynamics of the space shuttle orbiter
NASA Technical Reports Server (NTRS)
Rausch, J. R.; Roberge, A. M.
1973-01-01
A study was conducted to determine the external effects caused by operation of the reaction control system during entry of the space shuttle orbiter. The effects of jet plume-external flow interactions were emphasized. Force data were obtained for the basic airframe characteristics plus induced effects when the reaction control system is operating. Resulting control amplification and/or coupling were derived and their effects on the aerodynamic stability and control of the orbiter and the reaction control system thrust were determined.
Interdot Coulomb correlation effects and spin-orbit coupling in two carbon nanotube quantum dots
Wang, Zhen-Hua; Kuang, Xiao-Yu Zhong, Ming-Min; Shao, Peng; Li, Hui
2014-01-28
Transport properties of the two-level Kondo effect involving spin, orbital, and pseudospin degrees of freedom are examined in a parallel carbon nanotube double quantum dot with a sufficient interdot Coulomb interaction and small interdot tunneling. The interdot Coulomb correlation effects are taken into account, and it plays an important role in forming bonding and antibonding states. Attached to ferromagnetic leads, the Kondo effect is observed at the interdot Coulomb blockade region with degeneracy of spin, orbital, and pseudospin degrees of freedom. A crossover from a two-level Kondo state involving the fivefold degeneracy of the double quantum dots to an SU(4) spin-orbit Kondo state and to an SU(2) spin-Kondo effect is demonstrated. At finite magnetic field, the splitting of the spin, orbital, and pseudospin Kondo resonance can be restored. For finite intradot Coulomb interaction U, there is a competition between the single-dot Kondo effect and the antiferromagnetic exchange coupling J{sub AFM}, resulting in the suppression of the Kondo resonance. Moreover, both the J{sub AFM} and the Zeeman interactions compete, leading to need a much higher value of the magnetic field to compensate for the Kondo splitting.
Effective Interactions for Nuclear Structure Calculations
NASA Astrophysics Data System (ADS)
Signoracci, Angelo
Experimental interest in nuclei far from stability, especially due to proposed advancements in rare isotope facilities, has stimulated improvements in theoretical predictions of exotic isotopes. However, standard techniques developed for nuclear structure calculations, Configuration Interaction theory and Energy Density Functional methods, lack either the generality or the accuracy necessary for reliable calculations away from stability. Hybrid methods, which combine Configuration Interaction theory and Energy Density Functional methods in order to exploit their beneficial properties, are currently under investigation for improved theoretical capabilities. A new technique to produce nuclear Hamiltonians has been developed, implementing renormalization group methods, many-body perturbative techniques, and Energy Density Functional methods. Connection to the underlying physics is a primary focus, limiting the number of free parameters necessary in the procedure. The main benefit of this approach is the improvement in the quality of effective interactions outside of standard model spaces. In the Hybrid Renormalization Procedure developed in this dissertation, Skyrme energy density functionals provide a realistic single particle basis that accounts for the long tail of loosely bound orbits, especially significant for valence orbits of exotic isotopes. A microscopic nucleon-nucleon potential is softened with renormalization group techniques to eliminate the hard core of the nuclear interaction. Many-body perturbative techniques, in the form of Rayleigh-Schrodinger theory, implement the realistic basis to convert the low-momentum interaction into a model space of interest. The basis is an important ingredient in the renormalization and greatly affects the results obtained with the Hybrid Renormalization Procedure, specifically through the single particle energies derived from Skyrme functionals. A comparison of the standard harmonic oscillator basis and the realistic
Weak Te,Te interactions through the looking glass of NMR spin-spin coupling.
Bühl, Michael; Knight, Fergus R; Křístková, Anezka; Malkin Ondík, Irina; Malkina, Olga L; Randall, Rebecca A M; Slawin, Alexandra M Z; Woollins, J Derek
2013-02-25
Across the bay: J((125)Te, (125)Te) spin-spin coupling is a highly sensitive probe into the electronic and geometric structure of 1,8-peri-substituted naphthalene tellurium derivatives. The coupling is related to the onset of multicenter bonding in these systems.
Global nuclear structure effects of the tensor interaction
Zalewski, M.; Olbratowski, P.; Rafalski, M.; Werner, T. R.; Satula, W.; Wyss, R. A.
2009-12-15
A direct fit of the isoscalar spin-orbit (SO) and both isoscalar and isovector tensor coupling constants to the f{sub 5/2}-f{sub 7/2} SO splittings in {sup 40}Ca, {sup 56}Ni, and {sup 48}Ca nuclei requires a drastic reduction of the isoscalar SO strength and strong attractive tensor coupling constants. The aim of this work is to address further consequences of these strong attractive tensor and weak SO fields on binding energies, nuclear deformability, and high-spin states. In particular, the contribution to the nuclear binding energy from the tensor field shows a generic magic structure with tensorial magic numbers N(Z)=14,32,56, or 90, corresponding to the maximum spin asymmetries in 1d{sub 5/2}, 1f{sub 7/2}+2p{sub 3/2}, 1g{sub 9/2}+2d{sub 5/2}, and 1h{sub 11/2}+2f{sub 7/2} single-particle configurations, respectively, and that these numbers are smeared out by pairing correlations and deformation effects. The consequences of strong attractive tensor fields and weak SO interaction for nuclear stability at the drip lines are also examined, particularly those close to the tensorial doubly magic nuclei. The possibility of an entirely new tensor-force-driven deformation effect is discussed.
Virués-Ortega, Javier; Buela-Casal, Gualberto
2006-01-01
This paper reviews literature published on the psychophysiological effects of long-term human-animal interaction (i.e., pet ownership, pet adoption). A literature search was conducted using PsycInfo and Medline databases. Although the available evidence is far from being consistent, it can be concluded that, in some cases, long-term relationships with animals may moderate baseline physiological variables, particularly blood pressure. Results proved more coherent in studies where animals were adopted by owners as part of the procedure. This paper examines existing hypotheses seeking to account for these effects and the supporting evidence. Two major hypotheses have been suggested to explain the psychophysiological effects of long-term interaction, namely (1) stress-buffering effects of noncritical social support provided by pets; and (2) classical conditioning of relaxation. These mechanisms may partially account for the long-term health outcomes observed in a number of human-animal interaction studies. PMID:16462556
Spin-Josephson effects in exchange coupled antiferromagnetic insulators
NASA Astrophysics Data System (ADS)
Liu, Yizhou; Yin, Gen; Zang, Jiadong; Lake, Roger K.; Barlas, Yafis
2016-09-01
The spin superfluid analogy can be extended to include Josephson-like oscillations of the spin current. In a system of two antiferromagnetic insulators (AFMIs) separated by a thin metallic spacer, a threshold spin chemical potential established perpendicular to the direction of the Néel vector field drives terahertz oscillations of the spin current. This spin current also has a nonlinear, time-averaged component which provides a "smoking gun" signature of spin superfluidity. The time-averaged spin current can be detected via the inverse spin Hall effect in a metallic spacer with large spin-orbit coupling. The physics illustrated here with AFMIs also applies to easy-plane ferromagnetic insulators. These findings may provide a new approach for experimental verification of spin superfluidity and realization of a terahertz spin oscillator.
Solar electric propulsion thrust beam interactive effects
NASA Technical Reports Server (NTRS)
Sellen, J. M., Jr.; Fitzgerald, D. J.
1975-01-01
Interactive effects between ion engine thrust beams and an SEP spacecraft and its science payload have been examined. AC electric contamination from thrust beam potential fluctuations of both 'common mode' and 'point-to-point' forms has been evaluated. Quenching of point-to-point E-fields by both thrust ion and charge exchange ion plasmas is expected. Reduction methods for AC electric contamination from common mode thrust beam potential fluctuations have been developed. Charged particle contamination of ambient space and plasma wave contamination may result from density magnitude and spatial extent of charge exchange plasma plumes. Reduction methods for cone of directions of high angle charge exchange ions have been examined.
Simple effective interaction for dimensional crossover
NASA Astrophysics Data System (ADS)
Constantin, Lucian A.
2016-03-01
We show that the effective electron-electron interaction veff[n ] (r ,r') =erf [|r - r'|b (n ) ]/|r -r'| , with n being the electronic density and b (n ) fixed from the compressibility sum rule, is remarkably accurate in both three and two dimensions, competing with the actual state-of-the-art exchange-correlation static kernels. Using this result, we propose a simple isotropic approximation for the quasi-two-dimensional regime, which gives a realistic wave vector analysis of the correlation energy, in the context of the linear response time-dependent density functional theory.
NASA Astrophysics Data System (ADS)
Powell, Philip; Baym, Gordon; Sa de Melo, Carlos
We develop a finite temperature theory of ultracold three-dimensional Fermi gases in the presence of artificial spin-orbit coupling, Zeeman fields, and tunable s-wave interactions. With the inclusion of quadratic fluctuations, we compute both the critical temperature for superfluidity and the population of bound and unbound fermions throughout the evolution from the Bardeen-Cooper-Schrieffer (BCS) to Bose-Einstein condensate (BEC) regimes. In particular, we show that in the BEC regime, spin-orbit coupling is capable of increasing the critical temperature relative to the no-field case, by inducing a triplet component to the superfluid order parameter, while decreasing the many-body effective mass. We also derive the time-dependent Ginzburg-Landau equation to sixth-order in the superfluid order parameter, and obtain explicit expressions for the coefficients of the effective theory valid across the entire evolution from BCS to BEC superfluidity.
Effects of nicardipine on ventriculo-arterial coupling in humans.
Tanaka, K; Oshita, S; Kitahata, H; Kimura, H; Kawahito, S; Park, Y C; Sakabe, T
1998-08-01
The ratio of effective arterial elastance (Ea) to left ventricular elastance (Ees) is an indicator of the coupling between ventricular properties and arterial load properties. Another criterion for the coupling between an energy source and its load is the principle of economical fuel consumption, or mechanical efficiency, which is defined as the ratio of stroke work (SW) to myocardial oxygen consumption per beat (MVO2). It has been revealed that SW of ventricular contraction is maximized when Ea/Ees = 1, while mechanical efficiency is maximized when Ea/Ees = 0.5. The purpose of the present study was to investigate the ventriculo-arterial coupling during hypertension, and the effects of nicardipine on this relationship in surgical patients using Ea/Ees and SW/MVO2 as indicators. Anaesthesia was maintained with isoflurane, nitrous oxide, and fentanyl. Radial artery pressure was displayed on a polygraph, and left ventricular end-systolic and end-diastolic volumes were determined by use of transoesophageal echocardiography. Ees was calculated as MAP/(ESVI-4), where MAP is mean arterial pressure and ESVI is end-systolic volume index. Ea was calculated as the ratio of MAP to stroke volume index (SVI). Stroke work index (SWI) was calculated as the product of MAP and SVI. MVO2 was assessed by estimating the ventricular pressure-volume area index (PVAI), which is expressed as the sum of SWI and the end-systolic potential energy index. Before (baseline), and 3, 10, 20, and 30 min after i.v. nicardipine (30 micrograms kg-1), Ea/Ees and SWI/PVAI were determined in 14 surgical patients with intraoperative hypertension. Before nicardipine (during hypertension), Ea was almost equal to Ees, whereas Ea/Ees was significantly reduced to about 0.5-0.6 at 3, 10, and 20 min after nicardipine. SWI/PVAI was maximized and significantly greater than the baseline value at 3 min after nicardipine. These results suggest that, during hypertension, ventricular and arterial properties were so
NASA Astrophysics Data System (ADS)
Ayabe, Kazuki; Sato, Kazunobu; Nakazawa, Shigeaki; Nishida, Shinsuke; Sugisaki, Kenji; Ise, Tomoaki; Morita, Yasushi; Toyota, Kazuo; Shiomi, Daisuke; Kitagawa, Masahiro; Suzuki, Shuichi; Okada, Keiji; Takui, Takeji
2013-10-01
Weakly exchange-coupled biradicals have attracted much attention in terms of their dynamic nuclear polarisation application in NMR spectroscopy for biological systems or the use of synthetic electron-spin qubits in quantum information processing/quantum-computing technology. Analogues multi-partite molecular systems are important in entering a new phase of the relevant fields. Many stable organic biradicals known so far have nitrogen nuclei at their electron spin sites, where singly occupied molecular orbitals are dominating and large hyperfine couplings occur. A salient feature of such weakly exchange-coupled molecular systems in terms of electronic spin structures is underlain by small zero-field splitting (ZFS) parameters comparable with nuclear hyperfine and/or exchange interactions. Pulse-based electron spin nutation (ESN) spectroscopy of weakly exchange-coupled biradicals, applicable to oriented or non-oriented media, has proven to be a useful and facile approach to the determination of ZFS parameters, which reflect relatively short distances between unpaired electron spins. In the present study, we first treat two-dimensional single-crystal ESN spectroscopy (Q-band) of a 15N-labelled weakly exchange-coupled biradical, showing the nuclear hyperfine effects on the ESN phenomena from both the experimental and theoretical side. ESN spectroscopy is transition moment spectroscopy, in which the nutation frequency as a function of the microwave irradiation strength ω1 (angular frequency) for any cases of weakly exchange-coupled systems can be treated. The results provide a testing ground for the simplified but general approach to the ESN analysis. In this study, we have invoked single-crystal electron-electron double resonance measurements on a typical biradical well incorporated in a diamagnetic host lattice and checked the accuracy of our ESN analysis for the spin dipolar tensor and exchange interaction. Next, we extend the general approach to analogues multi
Effects of Marital Conflict on Subsequent Triadic Family Interactions and Parenting.
ERIC Educational Resources Information Center
Kitzmann, Katherine M.
2000-01-01
Observed 40 married couples interacting with their 6- to 8-year-old sons after pleasant and conflictual discussions to examine indirect effects of marital conflict on children through their disruptions in family alliances and parenting. Found stronger evidence than previously available of a causal link between conflict and disrupted parenting.…
High frequency chest compression effects on cardio-respiratory interaction.
Lee, Jongwon; Lee, Yong Wan; Warwick, Warren J
2008-01-01
In this study, we present a quantitative approach to the analysis of the HFCC effect on heart rate changes in the respiratory stage according to different pulsation conditions with HFCC pulsation and without HFCC pulsation. We have shown that the heart rate increases with higher pressure settings revealing different patterns depending on the respiration stages. For our interaction study of how the heart and lungs were affected by HFCC, phase synchronization was considered and compared under different conditions which determine the real biological phenomenon for nonlinear or linear oscillatory coupling. The subject for this study was young and healthy, so these preliminary results should be verified with more detailed studies from abundant subjects to increase HFCC efficacy for lung disease patients. Interestingly, the indication or tracking of heart rate changes, respiration rate changes, or synchronization epoch can be the standard index for how much the cardiac and respiratory system improve using HFCC during therapy time or after therapy time.
Cosmological effects of scalar-photon couplings: dark energy and varying-α Models
Avgoustidis, A.; Martins, C.J.A.P.; Monteiro, A.M.R.V.L.; Vielzeuf, P.E.; Luzzi, G. E-mail: Carlos.Martins@astro.up.pt E-mail: up110370652@alunos.fc.up.pt
2014-06-01
We study cosmological models involving scalar fields coupled to radiation and discuss their effect on the redshift evolution of the cosmic microwave background temperature, focusing on links with varying fundamental constants and dynamical dark energy. We quantify how allowing for the coupling of scalar fields to photons, and its important effect on luminosity distances, weakens current and future constraints on cosmological parameters. In particular, for evolving dark energy models, joint constraints on the dark energy equation of state combining BAO radial distance and SN luminosity distance determinations, will be strongly dominated by BAO. Thus, to fully exploit future SN data one must also independently constrain photon number non-conservation arising from the possible coupling of SN photons to the dark energy scalar field. We discuss how observational determinations of the background temperature at different redshifts can, in combination with distance measures data, set tight constraints on interactions between scalar fields and photons, thus breaking this degeneracy. We also discuss prospects for future improvements, particularly in the context of Euclid and the E-ELT and show that Euclid can, even on its own, provide useful dark energy constraints while allowing for photon number non-conservation.
Effect of vertical and lateral coupling between tyre and road on vehicle rollover
NASA Astrophysics Data System (ADS)
Li, Yinong; Sun, Wei; Huang, Jingying; Zheng, Ling; Wang, Yanyang
2013-08-01
The vehicle stability involves many aspects, such as the anti-rollover stability in extreme steering operations and the vehicle lateral stability in normal steering operations. The relationships between vehicle stabilities in extreme and normal circumstances obtain less attention according to the present research works. In this paper, the coupling interactions between vehicle anti-rollover and lateral stability, as well as the effect of road excitation, are taken into account on the vehicle rollover analysis. The results in this paper indicate that some parameters influence the different vehicle stabilities diversely or even contradictorily. And it has been found that there are contradictions between the vehicle rollover mitigation performance and the lateral stability. The direct cause for the contradiction is the lateral coupling between tyres and road. Tyres with high adhesion capacity imply that the vehicle possesses a high performance ability to keep driving direction, whereas the rollover risk of this vehicle increases due to the greater lateral force that tyres can provide. Furthermore, these contradictions are intensified indirectly by the vertical coupling between tyres and road. The excitation from road not only deteriorates the tyres' adhesive condition, but also has a considerable effect on the rollover in some cases.
Tütem, E; Apak, R; Sözgen, K
1996-02-01
Studying the interaction of antitumor-active anthraquinones with biologically important redox couples is important in understanding the possible reductive or oxidative mode of metabolism of these antineoplastic agents coupled with the formation of free radicals. The interactions of such anthraquinones, i.e., carminic acid (CA) and mitoxantrone (Mx) with iron(II, III) and copper(I, II) redox couples in oxygenated and deaerated solutions, were investigated by UV-Visible and IR-spectroscopy. The superoxide radical reagent, nitroblue tetrazolium (NBT), was added to the metal and anthraquinone solutions and their binary mixtures at varying pH. Formazan, the reduction product of NBT, was produced mainly as a result of Fe(II)-NBT and Fe(II)-Mx-NBT interactions. The ternary mixtures of the lower valencies of iron and copper with CA and NBT exhibited intensive charge-transfer bands in the visible region, while metal-Mx-NBT combinations did not produce such bands, possibly due to the blockage of the redox-active aminoethanolamine side-chains of Mx through coordination with the metals. Copper-Mx combinations showed an oxygen sensitivity as spectral evidence was obtained for the oxidative transformation of Mx to the cyclic primary metabolite. The results were evaluated in regard to the possible oxidative activation of the studied anthracenediones with iron and copper systems. PMID:8576709
Komendantov, Alexander O; Canavier, Carmen C
2002-03-01
The role of gap junctions between midbrain dopamine (DA) neurons in mechanisms of firing pattern generation and synchronization has not been well characterized experimentally. We modified a multi-compartment model of DA neuron by adding a spike-generating mechanism and electrically coupling the dendrites of two such neurons through gap junctions. The burst-generating mechanism in the model neuron results from the interaction of a N-methyl-D-aspartate (NMDA)-induced current and the sodium pump. The firing patterns exhibited by the two model neurons included low frequency (2-7 Hz) spiking, high-frequency (13-20 Hz) spiking, irregular spiking, regular bursting, irregular bursting, and leader/follower bursting, depending on the parameter values used for the permeability for NMDA-induced current and the conductance for electrical coupling. All of these firing patterns have been observed in physiological neurons, but a systematic dependence of the firing pattern on the covariation of these two parameters has not been established experimentally. Our simulations indicate that electrical coupling facilitates NMDA-induced burst firing via two mechanisms. The first can be observed in a pair of identical cells. At low frequencies (low NMDA), as coupling strength was increased, only a transition from asynchronous to synchronous single-spike firing was observed. At high frequencies (high NMDA), increasing the strength of the electrical coupling in an identical pair resulted in a transition from high-frequency single-spike firing to burst firing, and further increases led to synchronous high-frequency spiking. Weak electrical coupling destabilizes the synchronous solution of the fast spiking subsystems, and in the presence of a slowly varying sodium concentration, the desynchronized spiking solution leads to bursts that are approximately in phase with spikes that are not in phase. Thus this transitional mechanism depends critically on action potential dynamics. The second
NASA Astrophysics Data System (ADS)
Ogata, Tomomichi; Mizuta, Ryo; Adachi, Yukimasa; Murakami, Hiroyuki; Ose, Tomomaki
2016-04-01
Effect of air-sea coupling on the frequency distribution of intense tropical cyclones (TCs) over the northwestern Pacific (NWP) region is investigated using an atmosphere and ocean coupled general circulation model (AOGCM). Monthly varying flux adjustment enables AOGCM to simulate both subseasonal air-sea interaction and realistic seasonal to interannual SST variability. The maximum of intense TC distribution around 20-30°N in the AGCM shifts equatorward in the AOGCM due to the air-sea coupling. Hence AOGCM reduces northward intense TC distribution bias seen in AGCM. Over the NWP, AOGCM-simulated SST variability is large around 20-30°N where the warm mixed layer becomes shallower rapidly. Active entrainment from subsurface water over this region causes stronger SST cooling and hence TC intensity decreases. These results suggest that air-sea coupling characterized by subsurface oceanic condition causes more realistic distribution of intense TCs over the NWP.
NASA Astrophysics Data System (ADS)
Ogata, Tomomichi; Mizuta, Ryo; Adachi, Yukimasa; Murakami, Hiroyuki; Ose, Tomoaki
2015-12-01
Effect of air-sea coupling on the frequency distribution of intense tropical cyclones (TCs) over the northwestern Pacific (NWP) region is investigated using an atmosphere and ocean coupled general circulation model (AOGCM). Monthly varying flux adjustment enables AOGCM to simulate both subseasonal air-sea interaction and realistic seasonal to interannual sea surface temperature (SST) variability. The maximum of intense TC distribution around 20-30°N in the AGCM shifts equatorward in the AOGCM due to the air-sea coupling. Hence, AOGCM reduces northward intense TC distribution bias seen in AGCM. Over the NWP, AOGCM-simulated SST variability is large around 20-30°N where the warm mixed layer becomes shallower rapidly. Active entrainment from subsurface water over this region causes stronger SST cooling, and hence, TC intensity decreases. These results suggest that air-sea coupling characterized by subsurface oceanic condition causes more realistic distribution of intense TCs over the NWP.
Non-monotonic size dependence of diffusion and levitation effect: A mode-coupling theory analysis
NASA Astrophysics Data System (ADS)
Nandi, Manoj Kumar; Banerjee, Atreyee; Bhattacharyya, Sarika Maitra
2013-03-01
We present a study of diffusion of small tagged particles in a solvent, using mode coupling theory (MCT) analysis and computer simulations. The study is carried out for various interaction potentials. For the first time, using MCT, it is shown that only for strongly attractive interaction potential with allowing interpenetration between the solute-solvent pair the diffusion exhibits a non-monotonic solute size dependence which has earlier been reported in simulation studies [P. K. Ghorai and S. Yashonath, J. Phys. Chem. B 109, 5824-5835 (2005), 10.1021/jp046312w]. For weak attractive and repulsive potential the solute size dependence of diffusion shows monotonic behaviour. It is also found that for systems where the interaction potential does not allow solute-solvent interpenetration, the solute cannot explore the neck of the solvent cage. Thus these systems even with strong attractive interaction will never show any non-monotonic size dependence of diffusion. This non-monotonic size dependence of diffusion has earlier been connected to levitation effect [S. Yashonath and P. Santikary, J. Phys. Chem. 98, 6368 (1994), 10.1021/j100076a022]. We also show that although levitation is a dynamic phenomena, the effect of levitation can be obtained in the static radial distribution function.
Heller, Michal P; Janik, Romuald A; Spaliński, Michał; Witaszczyk, Przemysław
2014-12-31
Relativistic hydrodynamics simulations of quark-gluon plasma play a pivotal role in our understanding of heavy ion collisions at RHIC and LHC. They are based on a phenomenological description due to Müller, Israel, Stewart (MIS) and others, which incorporates viscous effects and ensures a well-posed initial value problem. Focusing on the case of conformal plasma we propose a generalization which includes, in addition, the dynamics of the least damped far-from-equilibrium degree of freedom found in strongly coupled plasmas through the AdS/CFT correspondence. We formulate new evolution equations for general flows and then test them in the case of N=4 super Yang-Mills plasma by comparing their solutions alongside solutions of MIS theory with numerical computations of isotropization and boost-invariant flow based on holography. In these tests the new equations reproduce the results of MIS theory when initialized close to the hydrodynamic stage of evolution, but give a more accurate description of the dynamics when initial conditions are set in the preequilibrium regime.
NASA Astrophysics Data System (ADS)
Heller, Michal P.; Janik, Romuald A.; Spaliński, Michał; Witaszczyk, Przemysław
2014-12-01
Relativistic hydrodynamics simulations of quark-gluon plasma play a pivotal role in our understanding of heavy ion collisions at RHIC and LHC. They are based on a phenomenological description due to Müller, Israel, Stewart (MIS) and others, which incorporates viscous effects and ensures a well-posed initial value problem. Focusing on the case of conformal plasma we propose a generalization which includes, in addition, the dynamics of the least damped far-from-equilibrium degree of freedom found in strongly coupled plasmas through the AdS/CFT correspondence. We formulate new evolution equations for general flows and then test them in the case of N =4 super Yang-Mills plasma by comparing their solutions alongside solutions of MIS theory with numerical computations of isotropization and boost-invariant flow based on holography. In these tests the new equations reproduce the results of MIS theory when initialized close to the hydrodynamic stage of evolution, but give a more accurate description of the dynamics when initial conditions are set in the preequilibrium regime.
NASA Astrophysics Data System (ADS)
Lindner, Helmut; Loper, Kristofer H.; Hahn, David W.; Niemax, Kay
2011-02-01
Particles produced by previous laser shots may have significant influence on the analytical signal in laser-induced breakdown spectroscopy (LIBS) and laser ablation inductively coupled plasma (LA-ICP) spectrometry if they remain close to the position of laser sampling. The effects of these particles on the laser-induced breakdown event are demonstrated in several ways. LIBS-experiments were conducted in an ablation cell at atmospheric conditions in argon or air applying a dual-pulse arrangement with orthogonal pre-pulse, i.e., plasma breakdown in a gas generated by a focussed laser beam parallel and close to the sample surface followed by a delayed crossing laser pulse in orthogonal direction which actually ablates material from the sample and produces the LIBS plasma. The optical emission of the LIBS plasma as well as the absorption of the pre-pulse laser was measured. In the presence of particles in the focus of the pre-pulse laser, the plasma breakdown is affected and more energy of the pre-pulse laser is absorbed than without particles. As a result, the analyte line emission from the LIBS plasma of the second laser is enhanced. It is assumed that the enhancement is not only due to an increase of mass ablated by the second laser but also to better atomization and excitation conditions favored by a reduced gas density in the pre-pulse plasma. Higher laser pulse frequencies increase the probability of particle-laser interaction and, therefore, reduce the shot-to-shot line intensity variation as compared to lower particle loadings in the cell. Additional experiments using an aerosol chamber were performed to further quantify the laser absorption by the plasma in dependence on time both with and without the presence of particles. The overall implication of laser-particle interactions for LIBS and LA-ICP-MS/OES are discussed.
Warner, James E.; Diaz, Manuel I.; Aquino, Wilkins; Bonnet, Marc
2014-01-01
This work focuses on the identification of heterogeneous linear elastic moduli in the context of frequency-domain, coupled acoustic-structure interaction (ASI), using either solid displacement or fluid pressure measurement data. The approach postulates the inverse problem as an optimization problem where the solution is obtained by minimizing a modified error in constitutive equation (MECE) functional. The latter measures the discrepancy in the constitutive equations that connect kinematically admissible strains and dynamically admissible stresses, while incorporating the measurement data as additional quadratic error terms. We demonstrate two strategies for selecting the MECE weighting coefficient to produce regularized solutions to the ill-posed identification problem: 1) the discrepancy principle of Morozov, and 2) an error-balance approach that selects the weight parameter as the minimizer of another functional involving the ECE and the data misfit. Numerical results demonstrate that the proposed methodology can successfully recover elastic parameters in 2D and 3D ASI systems from response measurements taken in either the solid or fluid subdomains. Furthermore, both regularization strategies are shown to produce accurate reconstructions when the measurement data is polluted with noise. The discrepancy principle is shown to produce nearly optimal solutions, while the error-balance approach, although not optimal, remains effective and does not need a priori information on the noise level. PMID:25339790
NASA Astrophysics Data System (ADS)
Munoz-Esparza, D.; Sauer, J.; Linn, R.
2015-12-01
Anomalous and unexpected fire behavior in complex terrain continues to result in substantial loss of property and extremely dangerous conditions for firefighting field personnel. We briefly discuss proposed hypotheses of fire interactions with atmospheric flows over complex terrain that can lead to poorly-understood and potentially catastrophic scenarios. Then, our recent results of numerical investigations via large-eddy simulation of coupled atmosphere-topography-fire phenomenology with the Los Alamos National Laboratory, HiGrad-Firetec model are presented as an example of the potential for increased understanding of these complex processes. This investigation focuses on the influence of downslope surface wind enhancement through stably stratified flow over an isolated hill, and the resulting dramatic changes in fire behavior including spread rate, and intensity. Implications with respect to counter-intuitive fire behavior and extreme fire events are discussed. This work demonstrates a tremendous opportunity to immediately create safer and more effective policy for field personnel through improved predictability of atmospheric conditions over complex terrain
NASA Astrophysics Data System (ADS)
Kim, Nam-Hui; Jung, Jinyong; Cho, Jaehun; Han, Dong-Soo; Yin, Yuxiang; Kim, June-Seo; Swagten, Henk J. M.; You, Chun-Yeol
2016-04-01
The interfacial Dzyaloshinskii-Moriya interaction (iDMI), surface anisotropy energy, and spin pumping at the Ir/Co interface are experimentally investigated by performing Brillouin light scattering. Contrary to previous reports, we suggest that the sign of the iDMI at the Ir/Co interface is the same as in the case of the Pt/Co interface. We also find that the magnitude of the iDMI energy density is relatively smaller than in the case of the Pt/Co interface, despite the large strong spin-orbit coupling (SOC) of Ir. The saturation magnetization and the perpendicular magnetic anisotropy (PMA) energy are significantly improved due to a strong SOC. Our findings suggest that an SOC in an Ir/Co system behaves in different ways for iDMI and PMA. Finally, we determine the spin pumping effect at the Ir/Co interface, and it increases the Gilbert damping constant from 0.012 to 0.024 for 1.5 nm-thick Co.
Felippa, Carlos A.; Sprague, Michael A.; Ross, Michael R.; Park, K. C.
2008-11-01
This paper is a sequel on the topic of localized Lagrange multipliers (LLM) for applications of fluid-structure interaction (FSI) between finite-element models of an acoustic fluid and an elastic structure. The prequel paper formulated the spatial-discretization methods, the LLM interface treatment, the time-marching partitioned analysis procedures, and the application to 1D benchmark problems. Here, we expand on formulation aspects required for successful application to more realistic 2D and 3D problems. Additional topics include duality relations at the fluid-structure interface, partitioned vibration analysis, reduced-order modeling, handling of curved interface surfaces, and comparison of LLM with other coupling methods. Emphasis is given to non-matching fluid-structure meshes. We present benchmark examples that illustrate the benefits and drawbacks of competing interface treatments. Realistic application problems involving the seismic response of two existing dams are considered. These include 2D modal analyses of the Koyna gravity dam, transient-response analyses of that dam with and without reduced-order modeling, incorporation of nonlinear cavitation effects, and the 3D transient-response analysis of the Morrow Point arch dam.
NASA Astrophysics Data System (ADS)
Warner, James E.; Diaz, Manuel I.; Aquino, Wilkins; Bonnet, Marc
2014-09-01
This work focuses on the identification of heterogeneous linear elastic moduli in the context of frequency-domain, coupled acoustic-structure interaction (ASI), using either solid displacement or fluid pressure measurement data. The approach postulates the inverse problem as an optimization problem where the solution is obtained by minimizing a modified error in constitutive equation (MECE) functional. The latter measures the discrepancy in the constitutive equations that connect kinematically admissible strains and dynamically admissible stresses, while incorporating the measurement data as additional quadratic error terms. We demonstrate two strategies for selecting the MECE weighting coefficient to produce regularized solutions to the ill-posed identification problem: 1) the discrepancy principle of Morozov, and 2) an error-balance approach that selects the weight parameter as the minimizer of another functional involving the ECE and the data misfit. Numerical results demonstrate that the proposed methodology can successfully recover elastic parameters in 2D and 3D ASI systems from response measurements taken in either the solid or fluid subdomains. Furthermore, both regularization strategies are shown to produce accurate reconstructions when the measurement data is polluted with noise. The discrepancy principle is shown to produce nearly optimal solutions, while the error-balance approach, although not optimal, remains effective and does not need a priori information on the noise level.
NASA Technical Reports Server (NTRS)
Miller, Arthur J.
1992-01-01
Midlatitude ocean-atmosphere interactions are studied in simulations from a simplified coupled model that includes synoptic-scale atmospheric variability, ocean current advection of SST, and air-sea heat exchange. Although theoretical dynamical ('identical twin') predictions using this model have shown that the SST anomalies in this model indeed influence the atmosphere, it is found here that standard cross correlation and empirical orthogonal function analyses of monthly mean model output yield the standard result, familiar from observational studies, that the atmosphere forces the ocean with little or no feedback. Therefore, these analyses are inconclusive and leave open the question of whether anomalous SST is influencing the atmosphere. In contrast, it is found that compositing strong warm events of model SST is a useful indicator of ocean forcing the atmosphere. Additional evidence is presented for oceanic influence on the atmosphere, namely, that ocean current advection appears to enhance the persistence of model SST anomalies through a feedback effect that is absent when only heat flux is allowed to influence SST anomaly evolution.
Bradley, Aaron J; Ugeda, Miguel M; da Jornada, Felipe H; Qiu, Diana Y; Ruan, Wei; Zhang, Yi; Wickenburg, Sebastian; Riss, Alexander; Lu, Jiong; Mo, Sung-Kwan; Hussain, Zahid; Shen, Zhi-Xun; Louie, Steven G; Crommie, Michael F
2015-04-01
Despite the weak nature of interlayer forces in transition metal dichalcogenide (TMD) materials, their properties are highly dependent on the number of layers in the few-layer two-dimensional (2D) limit. Here, we present a combined scanning tunneling microscopy/spectroscopy and GW theoretical study of the electronic structure of high quality single- and few-layer MoSe2 grown on bilayer graphene. We find that the electronic (quasiparticle) bandgap, a fundamental parameter for transport and optical phenomena, decreases by nearly one electronvolt when going from one layer to three due to interlayer coupling and screening effects. Our results paint a clear picture of the evolution of the electronic wave function hybridization in the valleys of both the valence and conduction bands as the number of layers is changed. This demonstrates the importance of layer number and electron-electron interactions on van der Waals heterostructures and helps to clarify how their electronic properties might be tuned in future 2D nanodevices.
Sto Domingo, N D; Refsgaard, A; Mark, O; Paludan, B
2010-01-01
The potential devastating effects of urban flooding have given high importance to thorough understanding and management of water movement within catchments, and computer modelling tools have found widespread use for this purpose. The state-of-the-art in urban flood modelling is the use of a coupled 1D pipe and 2D overland flow model to simultaneously represent pipe and surface flows. This method has been found to be accurate for highly paved areas, but inappropriate when land hydrology is important. The objectives of this study are to introduce a new urban flood modelling procedure that is able to reflect system interactions with hydrology, verify that the new procedure operates well, and underline the importance of considering the complete water cycle in urban flood analysis. A physically-based and distributed hydrological model was linked to a drainage network model for urban flood analysis, and the essential components and concepts used were described in this study. The procedure was then applied to a catchment previously modelled with the traditional 1D-2D procedure to determine if the new method performs similarly well. Then, results from applying the new method in a mixed-urban area were analyzed to determine how important hydrologic contributions are to flooding in the area.
Assessing Spurious Interaction Effects in Structural Equation Modeling
ERIC Educational Resources Information Center
Harring, Jeffrey R.; Weiss, Brandi A.; Li, Ming
2015-01-01
Several studies have stressed the importance of simultaneously estimating interaction and quadratic effects in multiple regression analyses, even if theory only suggests an interaction effect should be present. Specifically, past studies suggested that failing to simultaneously include quadratic effects when testing for interaction effects could…
Tamm State-Coupled Emission: Effect of Probe Location and Emission Wavelength
2015-01-01
We report the effect of the probe location and wavelength on the emission spatial distribution and spectral properties of fluorophores located on structures which display Tamm states. Our structure consists of a one-dimensional photonic crystal (1DPC)—that is, a multilayer structure of alternate high and low refractive index dielectrics—and a thin top silver film. Simulations show the presence of Tamm and surface plasmon modes in the structure. The electric field intensities for the Tamm modes are located mostly in the dielectric layer below the metal film. The corresponding field intensities for the surface plamon modes are located above the metal film in the distal side. Tamm states can be in resonance with the incident light normal or near normal to the surface, within the light line, and can be accessed without the use of a coupling prism or gratings. We investigated the emission spectra and angular distribution of the emission for probes located above and below the metal film to explore the interaction of fluorophores with Tamm plasmons and surface plasmons modes. Three probes were chosen with different overlap of the emission spectra with the Tamm modes. The fluorophores below the metal film coupled predominantly with the Tamm state and displayed more intense and only Tamm state-coupled emission (TSCE). Probes above the metal film display both surface plasmon-coupled emission (SPCE) and Tamm state-coupled emission. In contrast to SPCE, which shows only KR, P-polarized emission, the Tamm states can display both S- and P-polarized emission and can be populated using both RK and KR illuminations. The TSCE angle is highly sensitive to wavelength, which suggests the use of Tamm structures to provide both directional emission and wavelength dispersion. The combination of plasmonic and photonic structures with directional emission close to surface normal offers the opportunities for new design formats for clinical testing, portable devices, and other
Rau, Stefan; Main, Joerg; Wunner, Guenter
2010-08-15
The variational method of coupled Gaussian functions is applied to Bose-Einstein condensates with long-range interactions. The time dependence of the condensate is described by dynamical equations for the variational parameters. We present the method and analytically derive the dynamical equations from the time-dependent Gross-Pitaevskii equation. The stability of the solutions is investigated using methods of nonlinear dynamics. The concept presented in this article will be applied to Bose-Einstein condensates with monopolar 1/r and dipolar 1/r{sup 3} interaction in the subsequent article [S. Rau et al., Phys. Rev. A 82, 023611 (2010)], where we will present a wealth of phenomena obtained using the ansatz with coupled Gaussian functions.
Pedetta, Andrea; Parkinson, John S; Studdert, Claudia A
2014-09-01
Chemical signals sensed on the periplasmic side of bacterial cells by transmembrane chemoreceptors are transmitted to the flagellar motors via the histidine kinase CheA, which controls the phosphorylation level of the effector protein CheY. Chemoreceptor arrays comprise remarkably stable supramolecular structures in which thousands of chemoreceptors are networked through interactions between their cytoplasmic tips, CheA, and the small coupling protein CheW. To explore the conformational changes that occur within this protein assembly during signalling, we used in vivo cross-linking methods to detect close interactions between the coupling protein CheW and the serine receptor Tsr in intact Escherichia coli cells. We identified two signal-sensitive contacts between CheW and the cytoplasmic tip of Tsr. Our results suggest that ligand binding triggers changes in the receptor that alter its signalling contacts with CheW (and/or CheA).
Transverse effects of microbunch radiative interaction
Derbenev, Ya.S.; Shiltsev, V.D.
1996-06-03
In this article the authors study effects of microbunch cooperative electromagnetic radiation in a bend on transverse beam dynamics. An overtaking radiative interaction between different parts of the bunch results in three major forces variable along the bunch. Longitudinal force leads to energy loss and causes the bunch emittance growth in the bend due to the dispersion effect. Radial force consists of logarithmically large ``Talman`` centrifugal force and smaller centripetal force. Due to general radius-energy dependence in the bend, the ``Talman`` force does not affect beam dynamics while the centripetal force leads to projected emittance growth. Finally, radial and vertical focusing forces lead to trajectory distortions which vary along the bunch. These cooperative forces significantly affect the dynamics of short high-populated bunch in bends.
Quantum effects and nonlocality in strongly coupled plasmonic nanowire dimers.
Teperik, Tatiana V; Nordlander, Peter; Aizpurua, Javier; Borisov, Andrei G
2013-11-01
Using a fully quantum mechanical approach we study the optical response of a strongly coupled metallic nanowire dimer for variable separation widths of the junction between the nanowires. The translational invariance of the system allows to apply the time-dependent density functional theory (TDDFT) for nanowires of diameters up to 10 nm which is the largest size considered so far in quantum modeling of plasmonic dimers. By performing a detailed analysis of the optical extinction, induced charge densities, and near fields, we reveal the major nonlocal quantum effects determining the plasmonic modes and field enhancement in the system. These effects consist mainly of electron tunneling between the nanowires at small junction widths and dynamical screening. The TDDFT results are compared with results from classical electromagnetic calculations based on the local Drude and non-local hydrodynamic descriptions of the nanowire permittivity, as well as with results from a recently developed quantum corrected model. The latter provides a way to include quantum mechanical effects such as electron tunneling in standard classical electromagnetic simulations. We show that the TDDFT results can be thus retrieved semi-quantitatively within a classical framework. We also discuss the shortcomings of classical non-local hydrodynamic approaches. Finally, the implications of the actual position of the screening charge density at the gap interfaces are discussed in connection with plasmon ruler applications at subnanometric distances.
Anisotropic Paramagnetic Meissner Effect by Spin-Orbit Coupling.
Espedal, Camilla; Yokoyama, Takehito; Linder, Jacob
2016-03-25
Conventional s-wave superconductors repel an external magnetic field. However, a recent experiment [A. Di Bernardo et al., Phys. Rev. X 5, 041021 (2015)] has tailored the electromagnetic response of superconducting correlations via adjacent magnetic materials. We consider another route of altering the Meissner effect where spin-orbit interactions induce an anisotropic Meissner response that changes sign depending on the field orientation. The tunable electromagnetic response opens new paths in the utilization of hybrid systems comprising magnets and superconductors. PMID:27058095
Coupled interactions between volatile activity and Fe oxidation state during arc crustal processes
Humphreys, Madeleine C.S.; Brooker, R; Fraser, D.C.; Burgisser, A; Mangan, Margaret T.; McCammon, C
2015-01-01
Arc magmas erupted at the Earth’s surface are commonly more oxidized than those produced at mid-ocean ridges. Possible explanations for this high oxidation state are that the transfer of fluids during the subduction process results in direct oxidation of the sub-arc mantle wedge, or that oxidation is caused by the effect of later crustal processes, including protracted fractionation and degassing of volatile-rich magmas. This study sets out to investigate the effect of disequilibrium crustal processes that may involve coupled changes in H2O content and Fe oxidation state, by examining the degassing and hydration of sulphur-free rhyolites. We show that experimentally hydrated melts record strong increases in Fe3+/∑Fe with increasing H2O concentration as a result of changes in water activity. This is relevant for the passage of H2O-undersaturated melts from the deep crust towards shallow crustal storage regions, and raises the possibility that vertical variations in fO2 might develop within arc crust. Conversely, degassing experiments produce an increase in Fe3+/∑Fe with decreasing H2O concentration. In this case the oxidation is explained by loss of H2 as well as H2O into bubbles during decompression, consistent with thermodynamic modelling, and is relevant for magmas undergoing shallow degassing en route to the surface. We discuss these results in the context of the possible controls on fO2 during the generation, storage and ascent of magmas in arc settings, in particular considering the timescales of equilibration relative to observation as this affects the quality of the petrological record of magmatic fO2.
Sterile neutrino dark matter: Weak interactions in the strong coupling epoch
NASA Astrophysics Data System (ADS)
Venumadhav, Tejaswi; Cyr-Racine, Francis-Yan; Abazajian, Kevork N.; Hirata, Christopher M.
2016-08-01
We perform a detailed study of the weak interactions of standard model neutrinos with the primordial plasma and their effect on the resonant production of sterile neutrino dark matter. Motivated by issues in cosmological structure formation on small scales, and reported x-ray signals that could be due to sterile neutrino decay, we consider 7 keV-scale sterile neutrinos. Oscillation-driven production of such sterile neutrinos occurs at temperatures T ≳100 MeV , where we study two significant effects of weakly charged species in the primordial plasma: (1) the redistribution of an input lepton asymmetry; (2) the opacity for active neutrinos. We calculate the redistribution analytically above and below the quark-hadron transition, and match with lattice QCD calculations through the transition. We estimate opacities due to tree-level processes involving leptons and quarks above the quark-hadron transition, and the most important mesons below the transition. We report final sterile neutrino dark matter phase space densities that are significantly influenced by these effects, and yet relatively robust to remaining uncertainties in the nature of the quark-hadron transition. We also provide transfer functions for cosmological density fluctuations with cutoffs at k ≃10 h Mpc-1 , that are relevant to galactic structure formation.
NASA Astrophysics Data System (ADS)
Chiaramello, M.; Riconda, C.; Amiranoff, F.; Fuchs, J.; Grech, M.; Lancia, L.; Marquès, J.-R.; Vinci, T.; Weber, S.
2016-07-01
Plasma amplification of low energy, a short (˜100-500 fs) laser pulse by an energetic long (˜10 ps) pulse via strong coupling Stimulated Brillouin Backscattering is investigated with an extensive analysis of one-dimensional particle-in-cell simulations. Parameters relevant to nowadays experimental conditions are investigated. The obtained seed pulse spectra are analyzed as a function of the interaction conditions such as plasma profile, pulses delay, and seed or pulse duration. The factors affecting the amount of energy transferred are determined, and the competition between Brillouin-based amplification and parasitic Raman backscattering is analyzed, leading to the optimization of the interaction conditions.
Lenhart, Patricia M; Broselid, Stefan; Barrick, Cordelia J; Leeb-Lundberg, L M Fredrik; Caron, Kathleen M
2013-01-01
Receptor activity-modifying protein 3 (RAMP3) is a single-pass transmembrane protein known to interact with and affect the trafficking of several G-protein-coupled receptors (GPCRs). We sought to determine whether RAMP3 interacts with GPR30, also known as G-protein-coupled estrogen receptor 1. GPR30 is a GPCR that binds estradiol and has important roles in cardiovascular and endocrine physiology. Using bioluminescence resonance energy transfer titration studies, co-immunoprecipitation, and confocal microscopy, we show that GPR30 and RAMP3 interact. Furthermore, the presence of GPR30 leads to increased expression of RAMP3 at the plasma membrane in HEK293 cells. In vivo, there are marked sex differences in the subcellular localization of GPR30 in cardiac cells, and the hearts of Ramp3(-/-) mice also show signs of GPR30 mislocalization. To determine whether this interaction might play a role in cardiovascular disease, we treated Ramp3(+)(/)(+) and Ramp3(-/-) mice on a heart disease-prone genetic background with G-1, a specific agonist for GPR30. Importantly, this in vivo activation of GPR30 resulted in a significant reduction in cardiac hypertrophy and perivascular fibrosis that is both RAMP3 and sex dependent. Our results demonstrate that GPR30-RAMP3 interaction has functional consequences on the localization of these proteins both in vitro and in vivo and that RAMP3 is required for GPR30-mediated cardioprotection. PMID:23674134
Lenhart, Patricia M.; Broselid, Stefan; Barrick, Cordelia J.; Leeb-Lundberg, L.M. Fredrik; Caron, Kathleen M.
2013-01-01
Receptor activity modifying protein 3 (RAMP3) is a single pass transmembrane protein known to interact with and affect the trafficking of several G-protein coupled receptors (GPCRs). We sought to determine whether RAMP3 interacts with G-protein coupled receptor 30 (GPR30), also known as G-protein estrogen receptor 1 (GPER1). GPR30 is a GPCR that binds estradiol and has important roles in cardiovascular and endocrine physiology. Utilizing bioluminescence resonance energy transfer titration studies, co-immunoprecipitation, and confocal microscopy, we show that GPR30 and RAMP3 interact. Furthermore, the presence of GPR30 leads to increased expression of RAMP3 at the plasma membrane in HEK293 cells. In vivo, there are marked sex differences in the subcellular localization of GPR30 in cardiac cells, and the hearts of Ramp3−/− mice also show signs of GPR30 mislocalization. To determine whether this interaction might play a role in cardiovascular disease, we treated Ramp3+/+ and Ramp3−/− mice on a heart disease-prone genetic background with G-1, a specific agonist for GPR30. Importantly, this in vivo activation of GPR30 resulted in a significant reduction in cardiac hypertrophy and perivascular fibrosis that is both RAMP3- and sex-dependent. Our results demonstrate that GPR30-RAMP3 interaction has functional consequences on the localization of these proteins both in vitro and in vivo, and that RAMP3 is required for GPR30-mediated cardioprotection. PMID:23674134
NASA Astrophysics Data System (ADS)
Pujari, Sumiran; Lang, Thomas C.; Kaul, Ribhu K.
Bernal-stacked bilayer graphene hosts an interesting 'non-relativistic' semi-metallic dispersion different from monolayer graphene. At this quadratic band touching, short-range interactions are marginal and hence cause instabilities to a variety of ground states. In this work we consider the instabilities of even N species of fermions on the Bernal bilayer with an SU (N) -symmetric contact interaction. For SU (2) fermions with an on-site Hubbard interaction the ground state has been found to be to a magnetic Néel state for all strengths of the interaction. In contrast, the leading weak coupling instability for N > 2 is a non-magnetic ground state, which is gapped and odd under time reversal. On the other hand, at strong coupling we expect Néel or VBS ground states of the effective self-conjugate SU (N) spin models. Motivated by this observation, we investigate the phase diagram for even N > 2 using determinantal quantum Monte Carlo computations. Support from NSF Grant DMR-1056536 and XSEDE Grant DMR-150037.
NASA Astrophysics Data System (ADS)
Jiang, J.; Shimada, K.; Hayashi, H.; Iwasawa, H.; Aiura, Y.; Namatame, H.; Taniguchi, M.
2011-10-01
We examined the dimensionless coupling parameters of many-body interactions for a free-electron-like surface-derived state in Al(100) by means of high-resolution angle-resolved photoemission spectroscopy. A kink structure was found to exist in the energy-band dispersion near the Fermi level (EF), which was attributed to the electron-phonon interaction. At 50 K, the coupling parameters of the electron-phonon and electron-electron interactions were estimated as λep=0.67±0.05 and λee˜0.003, respectively, indicating that the effective mass enhancement was mainly derived from the electron-phonon interaction. The temperature dependence of the kink structure, as measured by λep(T), was consistent with a theoretical calculation based on the Eliashberg function. A quasiparticle peak with a width of 15-20 meV was found near EF, which was explained well by the simulated spectral function incorporating the self-energy evaluated in this study. We found that the electrons at the surface were strongly scattered by the defects at the surface and that the linewidth was significantly broadened (Γ0=0.238±0.006 eV).
Nishikawa, Isao; Tanaka, Gouhei; Horita, Takehiko; Aihara, Kazuyuki
2012-03-01
We investigate the diffusion coefficient of the time integral of the Kuramoto order parameter in globally coupled nonidentical phase oscillators. This coefficient represents the deviation of the time integral of the order parameter from its mean value on the sample average. In other words, this coefficient characterizes long-term fluctuations of the order parameter. For a system of N coupled oscillators, we introduce a statistical quantity D, which denotes the product of N and the diffusion coefficient. We study the scaling law of D with respect to the system size N. In other well-known models such as the Ising model, the scaling property of D is D∼O(1) for both coherent and incoherent regimes except for the transition point. In contrast, in the globally coupled phase oscillators, the scaling law of D is different for the coherent and incoherent regimes: D∼O(1/N(a)) with a certain constant a>0 in the coherent regime and D∼O(1) in the incoherent regime. We demonstrate that these scaling laws hold for several representative coupling schemes.
NASA Astrophysics Data System (ADS)
Ledbetter, M. P.; Romalis, M. V.; Kimball, D. F. Jackson
2013-01-01
A comparison between existing nuclear magnetic resonance measurements and calculations of the scalar spin-spin interaction (J coupling) in deuterated molecular hydrogen yields stringent constraints on anomalous spin-dependent potentials between nucleons at the atomic scale (˜1Å). The dimensionless coupling constant gPpgPN/4π associated with the exchange of pseudoscalar (axionlike) bosons between nucleons is constrained to be less than 3.6×10-7 for boson masses in the range of 5 keV, representing improvement by a factor of 100 over previous constraints. The dimensionless coupling constant gApgAN/4π associated with the exchange of an axial-vector boson between nucleons is constrained to be gApgAN/4π<1.3×10-19 for bosons of mass ≲1000eV, improving constraints at this distance scale by a factor of 100 for proton-proton couplings and more than 8 orders of magnitude for neutron-proton couplings.
Zhang, Xing; Herbert, John M.
2014-08-14
We revisit the calculation of analytic derivative couplings for configuration interaction singles (CIS), and derive and implement these couplings for its spin-flip variant for the first time. Our algorithm is closely related to the CIS analytic energy gradient algorithm and should be straightforward to implement in any quantum chemistry code that has CIS analytic energy gradients. The additional cost of evaluating the derivative couplings is small in comparison to the cost of evaluating the gradients for the two electronic states in question. Incorporation of an exchange-correlation term provides an ad hoc extension of this formalism to time-dependent density functional theory within the Tamm-Dancoff approximation, without the need to invoke quadratic response theory or evaluate third derivatives of the exchange-correlation functional. Application to several different conical intersections in ethylene demonstrates that minimum-energy crossing points along conical seams can be located at substantially reduced cost when analytic derivative couplings are employed, as compared to use of a branching-plane updating algorithm that does not require these couplings. Application to H{sub 3} near its D{sub 3h} geometry demonstrates that correct topology is obtained in the vicinity of a conical intersection involving a degenerate ground state.
NASA Astrophysics Data System (ADS)
Shepherd, James J.; Henderson, Thomas M.; Scuseria, Gustavo E.
2016-03-01
Over the past few years, pair coupled cluster doubles (pCCD) has shown promise for the description of strong correlation. This promise is related to its apparent ability to match results from doubly occupied configuration interaction (DOCI), even though the latter method has exponential computational cost. Here, by modifying the full configuration interaction quantum Monte Carlo algorithm to sample only the seniority zero sector of Hilbert space, we show that the DOCI and pCCD energies are in agreement for a variety of 2D Hubbard models, including for systems well out of reach for conventional configuration interaction algorithms. Our calculations are aided by the sign problem being much reduced in the seniority zero space compared with the full space. We present evidence for this and then discuss the sign problem in terms of the wave function of the system which appears to have a simplified sign structure.
Coupled Radiation Effects in Thermochemical Nonequilibrium Shock-Capturing Flowfield Calculations
NASA Technical Reports Server (NTRS)
Hartung, Lin C.; Mitcheltree, Robert A.; Gnoffo, Peter A.
1993-01-01
Lunar and Mars return conditions are examined using the LAURA flow field code and the LORAN radiation code to assess the effect of radiative coupling on axisymmetric thermochemical nonequilibrium flows. Coupling of the two codes is achieved iteratively. Special treatment required to couple radiation in a shock-capturing method is discussed. Results indicate that while coupling effects are generally the same as occur in equilibrium flows, under certain conditions radiation can modify the chemical kinetics of a nonequilibrium flow and thus alter relaxation processes. Coupling effects are found to be small for all cases considered, except for a five meter diameter aerobrake returning from Mars at 13.6 kilometers per second.
Salt Effects on the Conformational Stability of the Visual G-Protein-Coupled Receptor Rhodopsin
Reyes-Alcaraz, Arfaxad; Martínez-Archundia, Marlet; Ramon, Eva; Garriga, Pere
2011-01-01
Membrane protein stability is a key parameter with important physiological and practical implications. Inorganic salts affect protein stability, but the mechanisms of their interactions with membrane proteins are not completely understood. We have undertaken the study of a prototypical G-protein-coupled receptor, the α-helical membrane protein rhodopsin from vertebrate retina, and explored the effects of inorganic salts on the thermal decay properties of both its inactive and photoactivated states. Under high salt concentrations, rhodopsin significantly increased its activation enthalpy change for thermal bleaching, whereas acid denaturation affected the formation of a denatured loose-bundle state for both the active and inactive conformations. This behavior seems to correlate with changes in protonated Schiff-base hydrolysis. However, chromophore regeneration with the 11-cis-retinal chromophore and MetarhodopsinII decay kinetics were slower only in the presence of sodium chloride, suggesting that in this case, the underlying phenomenon may be linked to the activation of rhodopsin and the retinal release processes. Furthermore, the melting temperature, determined by means of circular dichroism and differential scanning calorimetry measurements, was increased in the presence of high salt concentrations. The observed effects on rhodopsin could indicate that salts favor electrostatic interactions in the retinal binding pocket and indirectly favor hydrophobic interactions at the membrane protein receptor core. These effects can be exploited in applications where the stability of membrane proteins in solution is highly desirable. PMID:22261069
NASA Astrophysics Data System (ADS)
Church, N. S.; Kasama, T.; Dunin-Borkowski, R.; Harrison, R. J.
2011-12-01
While single-domain and multidomain remanence are mature theories and are well supported by experiment, natural mineral samples may be influenced by processes that are not incorporated in these models. Particles exhibiting pseudo-single domain (PSD) behavior are frequently inferred using measurements such as Day et al. plots and first-order reversal curve diagrams of igneous and sedimentary rocks containing magnetite or greigite, yet an analogous model for PSD remanence is lacking, limiting the use of such samples as paleomagnetic recorders as well as quantitative characterisation of the magnetic grains. The role of interactions-magnetostatic or exchange-is similarly poorly understood in all but the simplest systems. This study presents direct observations of remanence states in mineral intergrowths which will be used to discuss the nature of the PSD state and systems with interacting particles and phases: questions of relevance both to paleomagnetists and the wider physics community. This study applies electron holography to synthetic titanomagnetite samples that reproduce grains that have undergone high-temperature oxidation, commonly observed in igneous rocks. The oxy-exsolved samples are dominated by submicron titanomagnetite grains intergrown with lamellae of titanohematite, which may be either paramagnetic, permitting the study of PSD behavior and magnetostatic interactions, or antiferromagnetic or ferrimagnetic, where exchange coupling can be a significant influence. Holography of magnetite and paramagnetic titanohematite shows that the PSD state can vary widely as a function of the applied field and the geometry of phases, including uniform magnetization and vortex states predicted by micromagnetic simulations. Particles that are uniformly magnetized may show strong magnetostatic interactions and can show a variety of switching mechanisms, including non-uniform rotation and domain walls spanning large regions of interacting particles. These observations
Song Fuzhan; Shen Xiangqian; Liu Mingquan; Xiang Jun
2012-01-15
SrFe{sub 12}O{sub 19} (SFO)/Ni{sub 0.5}Zn{sub 0.5}Fe{sub 2}O{sub 4} (NZFO) composite ferrite nanofibers with diameters about 120 nm have been prepared by the electrospinning and calcination process. The SFO/NZFO composite ferrites are formed after calcined at 700 Degree-Sign C for 2 h and the composite nanofibers with various mass ratios obtained at 900 Degree-Sign C are fabricated from NZFO grains about 16-40 nm and SFO grains of 19-45 nm with a uniform phase distribution. With the SFO ferrite content increasing, the coercivity (H{sub c}) and remanence (M{sub r}) for the composite ferrite nanofibers initially increase, reaching maximum values of 379.8 kA/m (297 K) and 242.2 kA/m (77 K), 39.1 Am{sup 2}/kg (297 K) and 53.5 Am{sup 2}/kg (77 K), respectively, at a mass ratio (SFO:NZFO) of 4, and then show a reduction tendency with a further increase of the mass ratio. This enhancement in magnetic properties is attributed to the competition of the exchange-coupling interaction and the dipolar interaction in the composite nanofibers. - Graphical abstract: SrFe{sub 12}O{sub 19} (SFO)/Ni{sub 0.5}Zn{sub 0.5}Fe{sub 2}O{sub 4} (NZFO) composite ferrite nanofibers with a uniform phase distribution show competition of the exchange-coupling interaction and the dipolar interaction in the composite nanofibers. Highlights: Black-Right-Pointing-Pointer Composite ferrite nanofibers have been prepared by the electrospinning. Black-Right-Pointing-Pointer Magnetic exchange-coupling interaction for these nanofibers were analyzed. Black-Right-Pointing-Pointer Nanofibers magnetic properties measured at 297 K and 77 K were discussed.
Effects of a Psychosocial Couple-Based Prevention Program on Adverse Birth Outcomes
Roettger, Michael E.; Jones, Damon E.; Paul, Ian M.; Kan, Marni L.
2015-01-01
Although maternal stress and depression have been linked to adverse birth outcomes (ABOs), few studies have investigated preventive interventions targeting maternal mental health as a means of reducing ABOs. This randomized controlled study examines the impact of Family Foundations (FF)—a transition to parenthood program for couples focused on promoting coparenting quality, with previously documented impact on maternal stress and depression—on ABOs. We also examine whether intervention buffers birth outcomes from the negative effect of elevated salivary cortisol levels. We use intent-to-treat analyses to assess the main effects of the FF intervention on ABOs (prematurity, birth weight, pregnancy complications, Cesarean section, and days in hospital for mothers and infants) among 148 expectant mothers. We also test the interaction of cortisol with intervention condition status in predicting ABOs. FF participation was associated with reduced risk of C-section (OR .357, p < 0.05, 95 % CI 0.149, 0.862), but did not have main effects on other ABOs. FF significantly buffered (p < 0.05) the negative impact of maternal cortisol on birth weight, gestational age, and days in hospital for infants; that is, among women with relatively higher levels of prenatal cortisol, the intervention reduced ABOs. These results demonstrate that a psycho-educational program for couples reduces incidence of ABOs among higher risk women. Future work should test whether reduced maternal stress and depression mediate these intervention effects. PMID:24969352
Effects of a psychosocial couple-based prevention program on adverse birth outcomes.
Feinberg, Mark E; Roettger, Michael E; Jones, Damon E; Paul, Ian M; Kan, Marni L
2015-01-01
Although maternal stress and depression have been linked to adverse birth outcomes (ABOs), few studies have investigated preventive interventions targeting maternal mental health as a means of reducing ABOs. This randomized controlled study examines the impact of Family Foundations (FF)-a transition to parenthood program for couples focused on promoting coparenting quality, with previously documented impact on maternal stress and depression-on ABOs. We also examine whether intervention buffers birth outcomes from the negative effect of elevated salivary cortisol levels. We use intent-to-treat analyses to assess the main effects of the FF intervention on ABOs (prematurity, birth weight, pregnancy complications, Cesarean section, and days in hospital for mothers and infants) among 148 expectant mothers. We also test the interaction of cortisol with intervention condition status in predicting ABOs. FF participation was associated with reduced risk of C-section (OR .357, p < 0.05, 95 % CI 0.149, 0.862), but did not have main effects on other ABOs. FF significantly buffered (p < 0.05) the negative impact of maternal cortisol on birth weight, gestational age, and days in hospital for infants; that is, among women with relatively higher levels of prenatal cortisol, the intervention reduced ABOs. These results demonstrate that a psycho-educational program for couples reduces incidence of ABOs among higher risk women. Future work should test whether reduced maternal stress and depression mediate these intervention effects.
NASA Technical Reports Server (NTRS)
Miller, Ron; Jiang, Xing-Jian; Travis, Larry (Technical Monitor)
2001-01-01
Tropical Atlantic SST shows a (statistically well-defined) decadal time scale in a 104-year simulation of unforced variability by a coupled general circulation model (CGCM). The SST anomalies superficially resemble observed Tropical Atlantic variability (TAV), and are associated with changes in the atmospheric circulation. Brazilian rainfall is modulated with a decadal time scale, along with the strength of the Atlantic trade winds, which are associated with variations in evaporation and the net surface heat flux. However, in contrast to observed tropical Atlantic variability, the trade winds damp the associated anomalies in ocean temperature, indicating a negative feedback. Tropical SST anomalies in the CGCM, though opposed by the surface heat flux, are advected in from the Southern Hemisphere mid-latitudes. These variations modulate the strength of the thermohaline circulation (THC): warm, salty anomalies at the equator sink drawing cold, fresh mid-latitude water. Upon reaching the equator, the latter inhibit vertical overturning and advection from higher latitudes, which allows warm, salty anomalies to reform, returning the cycle to its original state. Thus, the cycle results from advection of density anomalies and the effect of these anomalies upon the rate of vertical overturning and surface advection. This decadal modulation of Tropical Atlantic SST and the thermohaline circulation is correlated with ocean heat transport to the Northern Hemisphere high latitudes and Norwegian Sea SST. Because of the central role of equatorial convection, we question whether this mechanism is present in the current climate, although we speculate that it may have operated in palaeo times, depending upon the stability of the tropical water column.
Pluto's solar wind interaction: Collisional effects
NASA Astrophysics Data System (ADS)
Cravens, T. E.; Strobel, D. F.
2015-01-01
Exospheric neutral atoms and molecules (primarily N2, with trace amounts of CH4 and CO according to our current understanding of Pluto's atmosphere) escape from Pluto and travel into interplanetary space for millions of kilometers. Eventually, the neutrals are ionized by solar EUV photons and/or by collisions with solar wind electrons. The mass-loading associated with this ion pick-up is thought to produce a comet-like interaction of the solar wind with Pluto. Within a few thousand kilometers of Pluto the solar wind interaction should lead to a magnetic field pile-up and draping, as it does around other "non-magnetic" bodies such as Venus and comets. The structure of plasma regions and boundaries will be greatly affected by large gyroradii effects and the extensive exosphere. Energetic plasma should disappear from the flow within radial distances of a few thousand kilometers due to charge exchange collisions. An ionosphere should be present close to Pluto with a composition that is determined both by the primary ion production and ion-neutral chemistry. One question discussed in the paper is whether or not the ionosphere has a Venus-like sharply defined ionopause boundary or a diamagnetic cavity such as that found around comet Halley. Simple physical estimates of plasma processes and structures in the collision-dominated region are made in this paper and predictions are made for the New Horizons mission.
Predicting the phonon spectra of coupled nonlinear chains using effective phonon theory
NASA Astrophysics Data System (ADS)
Su, Ruixia; Yuan, Zongqiang; Wang, Jun; Zheng, Zhigang
2016-06-01
In general one-dimensional nonlinear lattices, extensive studies have discovered the existence of renormalized phonons due to nonlinear interactions and found these renormalized phonons, as the energy carriers, are responsible for heat transport. Within the framework of renormalized phonons, a generic form of renormalized phonon spectrum has been derived and effective phonon theory (EPT) has been developed to explain the heat transport in general 1D nonlinear lattices. Our attention is dedicated to generalizing the EPT for two-layer nonlinear lattices and deriving the analytic expression of phonon spectra. By calculating the phonon spectra of different coupled models with EPT, it is found that the phonon dispersion relation is in good agreement with the result obtained from the spectral energy density method. It is demonstrated that the EPT of a coupled system can predict the phonon spectra of two-layer nonlinear lattices well. Thus, this finding may shed light on the prediction of heat conduction behavior in a coupled system, qualitatively, and provide a useful guide for designing thermal devices.
NASA Astrophysics Data System (ADS)
Meetei, Oinam Nganba
Strong interactions in transition metal oxides can lead to spectacular phenomena like high Tc superconductivity and colossal magnetoresistance which have dominated materials research in the past decades. The goal of this thesis is to examine the interplay of strong correlations with additional degrees of freedom, like spin orbit coupling (SOC), multiple transition metal ions and disorder. We start with a discussion of Mott insulators, with the transition metal in the d4 configuration, where the competition between superexchange interaction and SOC leads to a novel ferromagnetic insulator. In recent years SOC has been at the center stage of condensed matter research because it can produce band insulators in uncorrelated materials with non-trivial topological properties. Here, we focus on the dual role of SOC and strong interactions, naturally realized in 4d/5dd transition metal oxides. We show that in d4 Mott insulators, the local moment can be altered by varying the relative strength of SOC and superexchange, both of which are small parameters compared to the interaction energy scale. In fact, a phase transition from a non-magnetic insulator with J=0 singlets at every site to an orbitally entangled ferromagnetic insulator occurs with decreasing SOC. Our results challenge the commonly held notion that local moments are robust in a Mott insulator. We identify candidate materials and present predictions for Resonant X-ray Scattering (RXS) signatures of the unusual magnetism in d4 Mott insulators. Next we focus on the double perovskite material Sr2 CrOsO6 which is an insulator and has the highest ferromagnetic Tc among all perovskites with a net moment. It presents several puzzles which we address systematically. Its insulating behavior cannot be explained from a band theory point of view or from a naive consideration of Mott physics. Additionally, the net moment at low temperature, M(0)=0.75 μΒ ,is unusual for half-filled bands where anti-ferromagnetism is expected
Azar, R. Julian; Head-Gordon, Martin
2012-01-14
We propose a wave function-based method for the decomposition of intermolecular interaction energies into chemically-intuitive components, isolating both mean-field- and explicit correlation-level contributions. We begin by solving the locally-projected self-consistent field for molecular interactions equations for a molecular complex, obtaining an intramolecularly polarized reference of self-consistently optimized, absolutely-localized molecular orbitals (ALMOs), determined with the constraint that each fragment MO be composed only of atomic basis functions belonging to its own fragment. As explicit inter-electronic correlation is integral to an accurate description of weak forces underlying intermolecular interaction potentials, namely, coordinated fluctuations in weakly interacting electronic densities, we add dynamical correlation to the ALMO polarized reference at the coupled-cluster singles and doubles level, accounting for explicit dispersion and charge-transfer effects, which map naturally onto the cluster operator. We demonstrate the stability of energy components with basis set extension, follow the hydrogen bond-breaking coordinate in the C{sub s}-symmetry water dimer, decompose the interaction energies of dispersion-bound rare gas dimers and other van der Waals complexes, and examine charge transfer-dominated donor-acceptor interactions in borane adducts. We compare our results with high-level calculations and experiment when possible.
Azar, R Julian; Head-Gordon, Martin
2012-01-14
We propose a wave function-based method for the decomposition of intermolecular interaction energies into chemically-intuitive components, isolating both mean-field- and explicit correlation-level contributions. We begin by solving the locally-projected self-consistent field for molecular interactions equations for a molecular complex, obtaining an intramolecularly polarized reference of self-consistently optimized, absolutely-localized molecular orbitals (ALMOs), determined with the constraint that each fragment MO be composed only of atomic basis functions belonging to its own fragment. As explicit inter-electronic correlation is integral to an accurate description of weak forces underlying intermolecular interaction potentials, namely, coordinated fluctuations in weakly interacting electronic densities, we add dynamical correlation to the ALMO polarized reference at the coupled-cluster singles and doubles level, accounting for explicit dispersion and charge-transfer effects, which map naturally onto the cluster operator. We demonstrate the stability of energy components with basis set extension, follow the hydrogen bond-breaking coordinate in the C(s)-symmetry water dimer, decompose the interaction energies of dispersion-bound rare gas dimers and other van der Waals complexes, and examine charge transfer-dominated donor-acceptor interactions in borane adducts. We compare our results with high-level calculations and experiment when possible.
Effect of chemical synapse on vibrational resonance in coupled neurons
NASA Astrophysics Data System (ADS)
Deng, Bin; Wang, Jiang; Wei, Xile
2009-03-01
The response of three coupled FitzHugh-Nagumo neurons, under high-frequency driving, to a subthreshold low-frequency signal is investigated. We show that an optimal amplitude of the high-frequency driving enhances the response of coupled excited neurons to a subthreshold low-frequency input, and the chemical synaptic coupling is more efficient than the well-known electrical coupling (gap junction), especially when the coupled neurons are near the canard regime, for local signal input, i.e., only one of the three neurons is subject to a low-frequency signal. The influence of additive noise and the interplay between vibrational and stochastic resonance are also analyzed.
Effective theory of interacting dark energy
Gleyzes, Jérôme; Mancarella, Michele; Vernizzi, Filippo; Langlois, David E-mail: langlois@apc.univ-paris7.fr E-mail: filippo.vernizzi@cea.fr
2015-08-01
We present a unifying treatment of dark energy and modified gravity that allows distinct conformal-disformal couplings of matter species to the gravitational sector. In this very general approach, we derive the conditions to avoid ghost and gradient instabilities. We compute the equations of motion for background quantities and linear perturbations. We illustrate our formalism with two simple scenarios, where either cold dark matter or a relativistic fluid is nonminimally coupled. This extends previous studies of coupled dark energy to a much broader spectrum of gravitational theories.
Álvarez, Yanina D.; Belingheri, Ana Verónica; Perez Bay, Andrés E.; Javis, Scott E.; Tedford, H. William; Zamponi, Gerald; Marengo, Fernando D.
2013-01-01
It is generally accepted that the immediately releasable pool is a group of readily releasable vesicles that are closely associated with voltage dependent Ca2+ channels. We have previously shown that exocytosis of this pool is specifically coupled to P/Q Ca2+ current. Accordingly, in the present work we found that the Ca2+ current flowing through P/Q-type Ca2+ channels is 8 times more effective at inducing exocytosis in response to short stimuli than the current carried by L-type channels. To investigate the mechanism that underlies the coupling between the immediately releasable pool and P/Q-type channels we transiently expressed in mouse chromaffin cells peptides corresponding to the synaptic protein interaction site of Cav2.2 to competitively uncouple P/Q-type channels from the secretory vesicle release complex. This treatment reduced the efficiency of Ca2+ current to induce exocytosis to similar values as direct inhibition of P/Q-type channels via ω-agatoxin-IVA. In addition, the same treatment markedly reduced immediately releasable pool exocytosis, but did not affect the exocytosis provoked by sustained electric or high K+ stimulation. Together, our results indicate that the synaptic protein interaction site is a crucial factor for the establishment of the functional coupling between immediately releasable pool vesicles and P/Q-type Ca2+ channels. PMID:23382986
Effect of spin-orbit couplings in graphene with and without potential modulation
NASA Astrophysics Data System (ADS)
Shakouri, Kh.; Masir, M. Ramezani; Jellal, A.; Choubabi, E. B.; Peeters, F. M.
2013-09-01
We investigate the effect of Rashba and intrinsic spin-orbit couplings on the electronic properties and spin configurations of Dirac fermions confined in: (i) a flat graphene sheet, (ii) a graphene wire with p-n-p structure, and (iii) a superlattice of graphene wires. The interplay between the spin-orbit interaction mechanisms breaks the electron-hole symmetry and the spin configuration induced by Rashba spin-orbit coupling lacks inversion symmetry in k space. We show that the Rashba spin-orbit interaction doubles the Fabry-Pérot resonant modes in the transmission spectrum of a graphene wire and opens new channels for the electron transmission. Moreover, it leads to the appearance of spin split extra Dirac cones in the energy spectrum of a graphene superlattice. It is shown that the spin of the electrons and holes confined in a flat graphene sheet is always perpendicular to their motion while this is not the case for the other nanostructures.
Xie, Ruimin; Johnson, Willie; Rodriguez, Lorna; Gounder, Murugesan; Hall, Gene S; Buckley, Brian
2007-04-01
To study the carboplatin-protein interaction, a sensitive method using size exclusion chromatography coupled to inductively coupled plasma mass spectrometry (SEC-ICP-MS) was developed. The complexes formed between plasma proteins and carboplatin were monitored and identified with this method. Composite blood plasma samples from patients who were undergoing chemotherapy were analyzed, and carboplatin was found to bind plasma proteins. In addition, blank plasma samples were spiked with carboplatin and were analyzed as a time course study, and the results confirmed that carboplatin formed complexes with plasma proteins, primarily albumin and gamma-globulin. To further substantiate the study, these two proteins were incubated with carboplatin. The binding between carboplatin and these proteins was then characterized qualitatively and quantitatively. In addition to a one-to-one binding of Pt to protein, protein aggregation was observed. The kinetics of the binding process of carboplatin to albumin and gamma-globulin was also studied. The initial reaction rate constant of carboplatin binding to albumin was determined to be 0.74 M(-1) min(-1), while that for gamma-globulin was 1.01 M(-1) min(-1), which are both lower than the rate constant of the cisplatin-albumin reaction previously reported.
NASA Astrophysics Data System (ADS)
Thomas, M. A.; Kahnert, M.; Andersson, C.; Kokkola, H.; Hansson, U.; Jones, C.; Langner, J.; Devasthale, A.
2015-06-01
To reduce uncertainties and hence to obtain a better estimate of aerosol (direct and indirect) radiative forcing, next generation climate models aim for a tighter coupling between chemistry transport models and regional climate models and a better representation of aerosol-cloud interactions. In this study, this coupling is done by first forcing the Rossby Center regional climate model (RCA4) with ERA-Interim lateral boundaries and sea surface temperature (SST) using the standard cloud droplet number concentration (CDNC) formulation (hereafter, referred to as the "stand-alone RCA4 version" or "CTRL" simulation). In the stand-alone RCA4 version, CDNCs are constants distinguishing only between land and ocean surface. The meteorology from this simulation is then used to drive the chemistry transport model, Multiple-scale Atmospheric Transport and Chemistry (MATCH), which is coupled online with the aerosol dynamics model, Sectional Aerosol module for Large Scale Applications (SALSA). CDNC fields obtained from MATCH-SALSA are then fed back into a new RCA4 simulation. In this new simulation (referred to as "MOD" simulation), all parameters remain the same as in the first run except for the CDNCs provided by MATCH-SALSA. Simulations are carried out with this model setup for the period 2005-2012 over Europe, and the differences in cloud microphysical properties and radiative fluxes as a result of local CDNC changes and possible model responses are analysed. Our study shows substantial improvements in cloud microphysical properties with the input of the MATCH-SALSA derived 3-D CDNCs compared to the stand-alone RCA4 version. This model setup improves the spatial, seasonal and vertical distribution of CDNCs with a higher concentration observed over central Europe during boreal summer (JJA) and over eastern Europe and Russia during winter (DJF). Realistic cloud droplet radii (CD radii) values have been simulated with the maxima reaching 13 μm, whereas in the stand
NASA Astrophysics Data System (ADS)
Fanaei, M.; Foerster, A.; Leymann, H. A. M.; Wiersig, J.
2016-10-01
We investigate two-mode photon correlations in a quantum-dot-microcavity laser with special emphasis on the effects induced by a direct coupling of two competing modes due to the dissipative character of the laser resonator. Numerical results based on a microscopic semiconductor theory reveal an enhanced autocorrelation of both modes and an enhanced anticorrelation between the modes. A detailed analysis is given in terms of dark and bright modes. It is shown that above the lasing threshold the original modes build up a bright mode coupled to the quantum dots and a dark mode, which interacts only indirectly with the quantum dots. We demonstrate that a populated dark mode can enable an efficient transfer of photons between the two original cavity modes, mediating an effective coupling between them.
NASA Astrophysics Data System (ADS)
Sommer, David; Peterson, Sean D.
2012-11-01
Voiced speech is a complex process that involves coupled interactions between expelled air and the vocal fold structure. Numerical simulations of this process are difficult due to the unsteady nature of the flow and boundary conditions, while experimental investigations are generally limited in the structural modeling. To bridge this gap, an experimental platform is investigated that couples a mechanical flow facility featuring instrumented and actuated walls, with a numerical structure solver. Specifically, a proof-of-concept experimental apparatus consisting of a flat plate oriented normal to a uniform jet is developed. The plate is instrumented with pressure sensors, which record the pressure distribution caused by the impinging jet. A real-time controller reads the pressure distribution and computes the integrated force on the plate. The resulting force is applied to a numerical structure model comprising a spring-mass-damper system, in which the dynamical parameters can be adjusted in software. The axial position and velocity of the plate are updated in real time based upon the numerical dynamics solution. In the future, this experimental facility will be extended to model two degrees of freedom asymmetric vocal fold motion with full fluid coupling. Pressure sensors distributed across the solid interface, as opposed to direct force sensors, will help explicate the effect of fluid-structure coupling on tissue loading and flow properties, thus allowing for more detailed validation and improvement of computational models.
More than bystanders: the effect of olefins on transition-metal-catalyzed cross-coupling reactions.
Johnson, Jeffrey B; Rovis, Tomislav
2008-01-01
Olefins and alkynes are ubiquitous in transition-metal catalysis, whether introduced by the substrate, the catalyst, or as an additive. Whereas the impact of metals and ligands is relatively well understood, the effects of olefins in these reactions are generally underappreciated, even though numerous examples of olefins influencing the outcome of a reaction, through increased activity, stability, or selectivity, have been reported. This Review provides an overview of the interaction of olefins with transition metals and documents examples of olefins influencing the outcome of catalytic reactions, in particular cross-coupling reactions. It should thus provide a basis for the improved understanding and further utilization of olefin and alkyne effects in transition-metal-catalyzed reactions.
Including the Effects of Electronic Excitations and Electron-Phonon Coupling in Cascade Simulations
Duffy, Dorothy |
2008-07-01
Radiation damage has traditionally been modeled using cascade simulations however such simulations generally neglect the effects of electron-ion interactions, which may be significant in high energy cascades. A model has been developed which includes the effects of electronic stopping and electron-phonon coupling in Molecular Dynamics simulations by means of an inhomogeneous Langevin thermostat. The energy lost by the atoms to electronic excitations is gained by the electronic system and the energy evolution of the electronic system is modeled by the heat diffusion equation. Energy is exchanged between the electronic system and the atoms in the Molecular Dynamics simulation by means of a Langevin thermostat, the temperature of which is the local electronic temperature. The model is applied to a 10 keV cascade simulation for Fe. (authors)
Effective Social Interaction Strategies for Inclusive Settings
ERIC Educational Resources Information Center
Terpstra, Judith E.; Tamura, Ronald
2008-01-01
Many strategies and interventions exist in the education of young children with disabilities. One area of intervention is that of social interaction, including social skills instruction, peer interaction strategies, and play skills. Interaction and social skill strategies for use with children with and without disabilities for the purpose of…
Next-to-leading order gravitational spin-orbit coupling in an effective field theory approach
Levi, Michele
2010-11-15
We use an effective field theory (EFT) approach to calculate the next-to-leading order (NLO) gravitational spin-orbit interaction between two spinning compact objects. The NLO spin-orbit interaction provides the most computationally complex sector of the NLO spin effects, previously derived within the EFT approach. In particular, it requires the inclusion of nonstationary cubic self-gravitational interaction, as well as the implementation of a spin supplementary condition (SSC) at higher orders. The EFT calculation is carried out in terms of the nonrelativistic gravitational field parametrization, making the calculation more efficient with no need to rely on automated computations, and illustrating the coupling hierarchy of the different gravitational field components to the spin and mass sources. Finally, we show explicitly how to relate the EFT derived spin results to the canonical results obtained with the Arnowitt-Deser-Misner (ADM) Hamiltonian formalism. This is done using noncanonical transformations, required due to the implementation of covariant SSC, as well as canonical transformations at the level of the Hamiltonian, with no need to resort to the equations of motion or the Dirac brackets.
Magneto-optical effects in interacting localized and propagating surface plasmon modes.
Torrado, Jorge F; González-Díaz, Juan B; González, María U; García-Martín, Antonio; Armelles, Gaspar
2010-07-19
We report that the effect of an external magnetic field on the propagation of surface plasmons can be effectively modified through the coupling between localized (LSP) and propagating (SPP) surface plasmons. When these plasmon modes do not interact, the main effect of the magnetic field is a modification of the wavevector of the SPP mode, leaving the LSP virtually unaffected. Once both modes start to interact, there is a strong variation of the magnetic field induced modification of the SPP dispersion curve and, simultaneously, the LSP mode becomes sensitive to the magnetic field.
Magnetocaloric effect at the exchange-inversion with magnetoelastic coupling
NASA Astrophysics Data System (ADS)
Piazzi, Marco; Basso, Vittorio
2015-09-01
We develop a thermodynamic model to describe antiferro- (AFM) to ferromagnetic (FM) phase transitions through magnetoelastic coupling in the framework of Kittel's exchange-inversion mechanism. By including both magnetic and structural contributions to the free energy, we derive the conditions to have a direct AFM-FM transition. These are represented either by the presence of a non-zero intra-sublattice coupling constant or by a sufficiently high value of the magnetoelastic coupling parameter. In the paper we establish these conditions by analytical means and we discuss the physical meaning of the model in relation to possible applications to magnetocaloric materials with AFM-FM transitions.
Effects of mounting and exciter coupling on vibrothermographic NDE
NASA Astrophysics Data System (ADS)
Vaddi, Jyani S.; Murray, Gabriel; Holland, Stephen D.
2015-03-01
Vibrothermography, also known as Sonic IR and Thermosonics, is notoriously sensitive to extrinsic parameters such as specimen mounting and transducer coupling. This is a result of the complicated resonances which deliver vibrational energy and allow the crack to heat up. We present an approximate theory which explains how the mechanical mounting and transducer coupling affect the resonances of the specimen, and compare this theory with simulation and experiment. Based on these explanations we suggest guidelines to assist practitioners in minimizing the sensitivity of their vibrothermography tests to specimen mounting and transducer coupling.
Cross-Cultural Consistency of the Demand/Withdraw Interaction Pattern in Couples
ERIC Educational Resources Information Center
Christensen, Andrew; Eldridge, Kathleen; Catta-Preta, Adriana Bokel; Lim, Veronica R.; Santagata, Rossella
2006-01-01
In order to examine the cross-cultural consistency of several patterns of couple communication, 363 participants from four different countries (Brazil, Italy, Taiwan, and the United States) completed self-report measures about communication and satisfaction in their romantic relationships. Across countries, constructive communication was…
NASA Technical Reports Server (NTRS)
Rockwell, Donald
1999-01-01
This program has involved, first of all, a critical state-of-the-art assessment of vortex-body interactions. Then, efforts were focused on experimental investigation on coupled-wake instabilities and turbulence occurring in a two-cylinder system. An extensive review was undertaken on the effect of incident vortices on various types of bodies. These incident vortices have a length scale of the same order of magnitude as the scale of the body. The body can take on various forms, including, for example, a circular cylinder, a blade or a wing. The classes of vortex-body interaction that were critically assessed include: (1) Periodic distortion of the incident (primary) vortex and shedding of secondary vorticity from the surface of the body. (2) Modulated vortex distortion and shedding at a leading-edge or surface due to incidence of a complex system of vortices. (3) Vortex distortion and shedding in presence of body oscillation. (4) Three-dimensional vortex interaction and shedding. For all of these classes of vortex-body interaction, quantitative topologies of the vorticity distributions and streamline patterns were found to be central to a unified description of mechanisms of vortex distortion and shedding. In most cases, it was possible to define relationships between vortex interactions and unsteady loading at the body surface. This phase of the program was an experimental investigation of a two-cylinder system, which simulated a central aspect of a four-wheel bogie on a large-scale commercial aircraft. The overall aim of this experimental research program was to determine the crucial elements of the unsteadiness in the gap and near-wake regions as a function of time using cinema-based techniques. During the research program, various image evaluation techniques were employed. They involved assessment of instantaneous velocity fields, streamline topology and patterns of vorticity. Experiments were performed in a large-scale water channel using a high
Chung, Stephen; Vafai, Kambiz
2014-01-01
The effects of hyperthermia, coupling attributes and property variations on Low-density lipoprotein (LDL) transport within a multi-layered wall while accounting for the fluid structure interaction (FSI) is analyzed in this work. To understand the potential impact of the hyperthermia process, thermo-induced attributes are incorporated, accounting for the plasma flow, mass transfer, as well as the elastic wall structure. The coupling effect of osmotic pressure, Soret and Dufour diffusion is discussed and their influence on LDL transport is examined, demonstrating that only the Soret effect needs to be accounted for. The effect of thermal expansion on changing the behavior of flow, mass transport, and elastic structure is illustrated and analyzed while incorporating the variations in the effective LDL diffusivity and consumption rate, as well as other dominating parameters. It is shown that hyperthermia results in an enhancement in LDL transport by increasing the concentration levels within the arterial wall. PMID:24183548
Rehman, Uzma S; Holtzworth-Munroe, Amy
2006-08-01
The authors used cross-cultural methodology to examine the demand-withdraw pattern of marital communication. In Western countries, women usually make more demands, whereas men are more likely to withdraw. But the recently advanced marital structure hypothesis suggests that this pattern can be altered by gender roles and beliefs, particularly in traditional marriages. To test such hypotheses, the authors conducted an observational study of marital communication across very different cultures, with varying levels of patriarchy (i.e., 50 White American couples, 52 Pakistani couples in Pakistan, and 48 immigrant Pakistani couples in America). Across cultures, demand-withdraw communication was related to marital distress, extending previous findings to new groups. However, the findings challenge the notion that demanding and withdrawing behaviors are inherently male or female; rather, the results point to the relevance of contextual factors, specifically gender power differences and acculturation, in understanding the demand-withdraw marital interaction pattern. Therapists working with foreign or immigrant couples must consider the cross-cultural generalizability of existing theories of marital communication. PMID:16881783
An investigation of the effects of pitch-roll (de)-coupling on helicopter handling qualities
NASA Technical Reports Server (NTRS)
Ockier, C. J.; Pausder, H. J.; Blanken, C. L.
1995-01-01
An investigation of the effects of pitch-roll coupling on helicopter handling qualities was performed by the US Army and DLR, using a NASA ground-based and a DLR inflight simulator. Over 90 different coupling configurations were evaluated using a roll-axis tracking task. The results show that although the current ADS-33C coupling criterion discriminates against those types of coupling typical of conventionally controlled helicopters, it not always suited for the prediction of handling qualities of helicopters with modern control systems. Based on the observation that high frequency inputs during tracking are used to alleviate coupling, a frequency domain pitch-roll coupling criterion that uses the average coupling ratio between the bandwidth and neutral stability frequency is formulated. This criterion provides a more comprehensive coverage with respect to the different types of coupling and shows excellent consistency.
NASA Astrophysics Data System (ADS)
Kemp, B. A.; Nikolayev, I.; Sheppard, C. J.
2016-04-01
Like-charges repel, and opposite charges attract. This fundamental tenet is a result of Coulomb's law. However, the electrostatic interactions between dielectric particles remain topical due to observations of like-charged particle attraction and the self-assembly of colloidal systems. Here, we show, using both an approximate description and an exact solution of Maxwell's equations, that nonlinear charged particle forces result even for linear material systems and can be responsible for anomalous electrostatic interactions such as like-charged particle attraction and oppositely charged particle repulsion. Furthermore, these electrostatic interactions and the deformation of such particles have fundamental implications for our understanding of macroscopic electrodynamics.
Optimal Scaling of Interaction Effects in Generalized Linear Models
ERIC Educational Resources Information Center
van Rosmalen, Joost; Koning, Alex J.; Groenen, Patrick J. F.
2009-01-01
Multiplicative interaction models, such as Goodman's (1981) RC(M) association models, can be a useful tool for analyzing the content of interaction effects. However, most models for interaction effects are suitable only for data sets with two or three predictor variables. Here, we discuss an optimal scaling model for analyzing the content of…
Zhao Xinyu; Jing Jun; Corn, Brittany; Yu Ting
2011-09-15
Non-Markovian dynamics is studied for two interacting qubits strongly coupled to a dissipative bosonic environment. We derive a non-Markovian quantum-state-diffusion (QSD) equation for the coupled two-qubit system without any approximations, and in particular, without the Markov approximation. As an application and illustration of our derived time-local QSD equation, we investigate the temporal behavior of quantum coherence dynamics. In particular, we find a strongly non-Markovian regime where entanglement generation is significantly modulated by the environmental memory. Additionally, we study residual entanglement in the steady state by analyzing the steady-state solution of the QSD equation. Finally, we discuss an approximate QSD equation.
NASA Astrophysics Data System (ADS)
Jing, Yumei; Huang, Shaoyun; Zhang, Kai; Wu, Jinxiong; Guo, Yunfan; Peng, Hailin; Liu, Zhongfan; Xu, H. Q.
2016-01-01
The electron transport properties of a topological insulator Bi2Se3 thin film are studied in Hall-bar geometry. The film with a thickness of 10 nm is grown by van der Waals epitaxy on fluorophlogopite mica and Hall-bar devices are fabricated from the as-grown film directly on the mica substrate. Weak antilocalization and electron-electron interaction effects are observed and analyzed at low temperatures. The phase-coherence length extracted from the measured weak antilocalization characteristics shows a strong power-law increase with decreasing temperature and the transport in the film is shown to occur via coupled multiple (topological surface and bulk states) channels. The conductivity of the film shows a logarithmical decrease with decreasing temperature and thus the electron-electron interaction plays a dominant role in quantum corrections to the conductivity of the film at low temperatures.
Jing, Yumei; Huang, Shaoyun; Zhang, Kai; Wu, Jinxiong; Guo, Yunfan; Peng, Hailin; Liu, Zhongfan; Xu, H Q
2016-01-28
The electron transport properties of a topological insulator Bi2Se3 thin film are studied in Hall-bar geometry. The film with a thickness of 10 nm is grown by van der Waals epitaxy on fluorophlogopite mica and Hall-bar devices are fabricated from the as-grown film directly on the mica substrate. Weak antilocalization and electron-electron interaction effects are observed and analyzed at low temperatures. The phase-coherence length extracted from the measured weak antilocalization characteristics shows a strong power-law increase with decreasing temperature and the transport in the film is shown to occur via coupled multiple (topological surface and bulk states) channels. The conductivity of the film shows a logarithmical decrease with decreasing temperature and thus the electron-electron interaction plays a dominant role in quantum corrections to the conductivity of the film at low temperatures.
On strongly interacting internal waves in a rotating ocean and coupled Ostrovsky equations.
Alias, A; Grimshaw, R H J; Khusnutdinova, K R
2013-06-01
In the weakly nonlinear limit, oceanic internal solitary waves for a single linear long wave mode are described by the KdV equation, extended to the Ostrovsky equation in the presence of background rotation. In this paper we consider the scenario when two different linear long wave modes have nearly coincident phase speeds and show that the appropriate model is a system of two coupled Ostrovsky equations. These are systematically derived for a density-stratified ocean. Some preliminary numerical simulations are reported which show that, in the generic case, initial solitary-like waves are destroyed and replaced by two coupled nonlinear wave packets, being the counterpart of the same phenomenon in the single Ostrovsky equation. PMID:23822486
Korona, Tatiana
2008-06-14
A new method for the calculation of the first-order intermolecular exchange energy is proposed. It is based on the partition of two-particle density matrices of monomers into the antisymmetrized product of one-particle density matrices and the remaining cumulant part. This partition is used to modify the formula for the first-order exchange energy developed by Moszynski et al. [J. Chem. Phys. 100, 5080 (1994)]. The new expression has been applied for the case of monomer density matrices derived from the expectation value expression for the coupled cluster singles and doubles wave function. In this way an accurate method of calculation of the first-order exchange energy for many-electron systems has been obtained, where both monomers are described on the coupled cluster level. Numerical results are presented for several benchmark van der Waals systems to illustrate the performance of the new approach.
On strongly interacting internal waves in a rotating ocean and coupled Ostrovsky equations.
Alias, A; Grimshaw, R H J; Khusnutdinova, K R
2013-06-01
In the weakly nonlinear limit, oceanic internal solitary waves for a single linear long wave mode are described by the KdV equation, extended to the Ostrovsky equation in the presence of background rotation. In this paper we consider the scenario when two different linear long wave modes have nearly coincident phase speeds and show that the appropriate model is a system of two coupled Ostrovsky equations. These are systematically derived for a density-stratified ocean. Some preliminary numerical simulations are reported which show that, in the generic case, initial solitary-like waves are destroyed and replaced by two coupled nonlinear wave packets, being the counterpart of the same phenomenon in the single Ostrovsky equation.
Photon-photon interaction in strong-coupling cavity-atom system
Yang, Jian; Kwiat, Paul G.
2014-12-04
We study photon-photon interactions mediated by a cavity-atom system in the strongcoupling regime of cavity quantum electrodynamics (QED). Different temporal shapes of the incident photons have been explored via numerical calculations. Especially, time-reversed photons can be in the cavity simultaneously and potentially acquire strong interaction with each other, advancing quantum information applications, e.g., quantum non-demolition (QND) measurement.
NASA Technical Reports Server (NTRS)
Tu, Eugene L.
1992-01-01
The thin-layer Navier-Stokes equations are solved numerically to investigate the effects of canard vertical position on a close-coupled canard-wing-body configuration at a transonic Mach number of 0.90 and angles of attack ranging from -2 to 12 degrees. Canard-wing interactions are investigated for high-, mid- and low-canard positions. The computational results show favorable canard-wing interactions for the high- and mid-canard configurations. The unfavorable lift and drag characteristics for the low-canard configuration are examined by analyses of the low-canard flowfield structure.
ERIC Educational Resources Information Center
Hoffman, Daniel L.
2013-01-01
The purpose of the study is to better understand the role of physicality, interactivity, and interface effects in learning with digital content. Drawing on work in cognitive science, human-computer interaction, and multimedia learning, the study argues that interfaces that promote physical interaction can provide "conceptual leverage"…
Influence of Rashba spin-orbit coupling on the Kondo effect
NASA Astrophysics Data System (ADS)
Wong, Arturo; Ulloa, Sergio E.; Sandler, Nancy; Ingersent, Kevin
2016-02-01
An Anderson model for a magnetic impurity in a two-dimensional electron gas with bulk Rashba spin-orbit interaction is solved using the numerical renormalization group under two different experimental scenarios. For a fixed Fermi energy, the Kondo temperature TK varies weakly with Rashba coupling λR, as reported previously. If instead the band filling is low and held constant, increasing λR can drive the system into a helical regime with exponential enhancement of TK. Under either scenario, thermodynamic properties at low temperatures T exhibit the same dependencies on T /TK as are found for λR=0 . Unlike the conventional Kondo effect, however, the impurity exhibits static spin correlations with conduction electrons of nonzero orbital angular momentum about the impurity site. We also consider a magnetic field that Zeeman splits the conduction band but not the impurity level, an effective picture that arises under a proposed route to access the helical regime in a driven system. The impurity contribution to the system's ground-state angular momentum is found to be a universal function of the ratio of the Zeeman energy to a temperature scale that is not TK (as would be the case in a magnetic field that couples directly to the impurity spin), but rather is proportional to TK divided by the impurity hybridization width. This universal scaling is explained via a perturbative treatment of field-induced changes in the electronic density of states.
The effect of driven electron-phonon coupling on the electronic conductance of a polar nanowire
Mardaani, Mohammad Rabani, Hassan; Esmaili, Esmat; Shariati, Ashrafalsadat
2015-08-07
A semi-classical model is proposed to explore the effect of electron-phonon coupling on the coherent electronic transport of a polar chain which is confined between two rigid leads in the presence of an external electric field. To this end, we construct the model by means of Green's function technique within the nearest neighbor tight-binding and harmonic approximations. For a time-periodic electric field, the atomic displacements from the equilibrium positions are obtained precisely. The result is then used to compute the electronic transport properties of the chain within the Peierls-type model. The numerical results indicate that the conductance of the system shows interesting behavior in some special frequencies. For each special frequency, there is an electronic quasi-state in which the scattering of electrons by vibrating atoms reaches maximum. The system electronic conductance decreases dramatically at the strong electron-phonon couplings and low electron energies. In the presence of damping forces, the electron-phonon interaction has a less significant effect on the conductance.
Egorov, V.S.; Lebedev, V.N.; Mekhov, I.B.; Moroshkin, P.V.; Chekhonin, I.A.; Bagayev, S.N.
2004-03-01
The nonstationary pump-probe interaction between short laser pulses propagating in a resonant optically dense coherent medium is considered. Special attention is paid to the case where the density of two-level particles is high enough that a considerable part of the energy of relatively weak external laser fields can be coherently absorbed and reemitted by the medium. Thus, the field of the medium reaction plays a key role in the interaction processes, which leads to collective behavior of an atomic ensemble in the strongly coupled light-matter system. Such behavior results in fast excitation interchanges between the field and a medium in the form of optical ringing, which is analogous to polariton beating in solid-state optics. This collective oscillating response, which can be treated as successive beats between light wave packets of different group velocities, is shown to significantly affect the propagation and amplification of the probe field under its nonlinear interaction with a nearly copropagating pump pulse. Depending on the probe-pump time delay, the probe transmission spectra show the appearance of either a specific doublet or coherent dip. The widths of these features are determined by the density-dependent field-matter coupling coefficient and increase during the propagation. Besides that, the widths of the coherent features, which appear close to resonance in the broadband probe spectrum, exceed the absorption-line width, since under the strong-coupling regime, the frequency of optical ringing exceeds the rate of incoherent relaxation. Contrary to stationary strong-field effects, the density- and coordinate-dependent transmission spectra of the probe manifest the importance of collective oscillations and cannot be obtained in the framework of a single-atom model.
NASA Technical Reports Server (NTRS)
Santanello, Joseph A., Jr.; Peters-Lidard, Christa D.; Kumar, Sujay V.
2011-01-01
The inherent coupled nature of earth s energy and water cycles places significant importance on the proper representation and diagnosis of land atmosphere (LA) interactions in hydrometeorological prediction models. However, the precise nature of the soil moisture precipitation relationship at the local scale is largely determined by a series of nonlinear processes and feedbacks that are difficult to quantify. To quantify the strength of the local LA coupling (LoCo), this process chain must be considered both in full and as individual components through their relationships and sensitivities. To address this, recent modeling and diagnostic studies have been extended to 1) quantify the processes governing LoCo utilizing the thermodynamic properties of mixing diagrams, and 2) diagnose the sensitivity of coupled systems, including clouds and moist processes, to perturbations in soil moisture. This work employs NASA s Land Information System (LIS) coupled to the Weather Research and Forecasting (WRF) mesoscale model and simulations performed over the U.S. Southern Great Plains. The behavior of different planetary boundary layers (PBL) and land surface scheme couplings in LIS WRF are examined in the context of the evolution of thermodynamic quantities that link the surface soil moisture condition to the PBL regime, clouds, and precipitation. Specifically, the tendency toward saturation in the PBL is quantified by the lifting condensation level (LCL) deficit and addressed as a function of time and space. The sensitivity of the LCL deficit to the soil moisture condition is indicative of the strength of LoCo, where both positive and negative feedbacks can be identified. Overall, this methodology can be applied to any model or observations and is a crucial step toward improved evaluation and quantification of LoCo within models, particularly given the advent of next-generation satellite measurements of PBL and land surface properties along with advances in data assimilation
Effects of multijet coupling on propulsive performance in underwater pulsed jets
NASA Astrophysics Data System (ADS)
Athanassiadis, Athanasios G.; Hart, Douglas P.
2016-07-01
Despite the importance of pulsed jets for underwater propulsion, the effect of multiple-jet interactions remains poorly understood. We experimentally investigate how interactions between parallel jets in a pulsed-jet thruster affect the thruster's propulsive performance. Using high-speed fluorescence imaging, we investigate the mutual influence of two pulsed jets under conditions relevant to low-speed maneuvering in a vehicle (Re ≈350 , L /D ≤2 ). Thrust production and propulsive efficiency are evaluated for different nozzle spacings using a new force estimation technique based on the fluorescence data. This analysis reveals that compared to noninteracting jets, the efficiency and thrust generated by the pair of interacting jets can fall by as much as 10% when the jets are brought into close proximity. Empirically, the thrust T falls off with the nondimensional jet spacing Δ ˜ as T =T∞(1 -C o Δ˜-6) for a thrust coupling coefficient C o =2.04 ±0.11 . Finally, we predict this dependence of thrust on spacing using a model that relates the thrust and efficiency drop to streamline curvature and vortex induction at the nozzles.
NASA Astrophysics Data System (ADS)
Campo, L.; Castelli, F.; Entekhabi, D.; Caparrini, F.
2009-09-01
A valid tool for the retrieving of the turbulent fluxes that characterize the surface energy budget is constituted by the remote sensing of land surface states. In this study sequences of satellite-derived observations (from SEVIRI sensors aboard the Meteosat Second Generation) of Land Surface Temperature have been used as input in a data assimilation scheme in order to retrieve parameters that describe energy balance at the ground surface in the Tuscany region, in central Italy, during summer 2005. A parsimonious 1-D multiscale variational assimilation procedure has been followed, that requires also near surface meteorological observations. A simplified model of the surface energy balance that includes such assimilation scheme has been coupled with the limited area atmospheric model RAMS, in order to improve in the latter the accuracy of the energy budget at the surface. The coupling has been realized replacing the assimilation scheme products, in terms of surface turbulent fluxes and temperature and humidity states during the meteorological simulation. Comparisons between meteorological model results with and without coupling with the assimilation scheme are discussed, both in terms of reconstruction of surface variables and of vertical characterization of the lower atmosphere. In particular, the effects of the coupling on the moisture feedback between surface and atmosphere are considered and estimates of the precipitation recycling ratio are provided. The results of the coupling experiment showed improvements in the reconstruction of the surface states by the atmospheric model and considerable influence on the atmospheric dynamics.
Numerical Simulation of CO2 Flooding of Coalbed Methane Considering the Fluid-Solid Coupling Effect.
Liu, Jianjun; Li, Guang; Zhang, Yue
2016-01-01
CO2 flooding of coalbed methane (CO2-ECBM) not only stores CO2 underground and reduces greenhouse gas emissions but also enhances the gas production ratio. This coupled process involves multi-phase fluid flow and coal-rock deformation, as well as processes such as competitive gas adsorption and diffusion from the coal matrix into fractures. A dual-porosity medium that consists of a matrix and fractures was built to simulate the flooding process, and a mathematical model was used to consider the competitive adsorption, diffusion and seepage processes and the interaction between flow and deformation. Due to the effects of the initial pressure and the differences in pressure variation during the production process, permeability changes caused by matrix shrinkage were spatially variable in the reservoir. The maximum value of permeability appeared near the production well, and the degree of rebound decreased with increasing distance from the production well.
Numerical Simulation of CO2 Flooding of Coalbed Methane Considering the Fluid-Solid Coupling Effect
Liu, Jianjun; Li, Guang; Zhang, Yue
2016-01-01
CO2 flooding of coalbed methane (CO2-ECBM) not only stores CO2 underground and reduces greenhouse gas emissions but also enhances the gas production ratio. This coupled process involves multi-phase fluid flow and coal-rock deformation, as well as processes such as competitive gas adsorption and diffusion from the coal matrix into fractures. A dual-porosity medium that consists of a matrix and fractures was built to simulate the flooding process, and a mathematical model was used to consider the competitive adsorption, diffusion and seepage processes and the interaction between flow and deformation. Due to the effects of the initial pressure and the differences in pressure variation during the production process, permeability changes caused by matrix shrinkage were spatially variable in the reservoir. The maximum value of permeability appeared near the production well, and the degree of rebound decreased with increasing distance from the production well. PMID:27031096
Numerical Simulation of CO2 Flooding of Coalbed Methane Considering the Fluid-Solid Coupling Effect.
Liu, Jianjun; Li, Guang; Zhang, Yue
2016-01-01
CO2 flooding of coalbed methane (CO2-ECBM) not only stores CO2 underground and reduces greenhouse gas emissions but also enhances the gas production ratio. This coupled process involves multi-phase fluid flow and coal-rock deformation, as well as processes such as competitive gas adsorption and diffusion from the coal matrix into fractures. A dual-porosity medium that consists of a matrix and fractures was built to simulate the flooding process, and a mathematical model was used to consider the competitive adsorption, diffusion and seepage processes and the interaction between flow and deformation. Due to the effects of the initial pressure and the differences in pressure variation during the production process, permeability changes caused by matrix shrinkage were spatially variable in the reservoir. The maximum value of permeability appeared near the production well, and the degree of rebound decreased with increasing distance from the production well. PMID:27031096
Further understanding of Huygens’ coupled clocks: The effect of stiffness
NASA Astrophysics Data System (ADS)
Peña Ramirez, J.; Aihara, K.; Fey, R. H. B.; Nijmeijer, H.
2014-03-01
A simplified model of the classical Huygens’ experiment on synchronization of pendulum clocks is examined. The model consists of two pendula coupled by an elastically supported rigid bar. The synchronized limit behaviour of the system, i.e. in-phase and anti-phase synchronization of the pendula, is studied as a function of the stiffness of the spring that supports the coupling bar. It is demonstrated that the stiffness has a large influence on the existence, stability, and oscillation frequency of the in-phase solution. The relationship between the obtained results and experimental results that have been reported in the literature, including Huygens’ original observations, is stressed.
Nuclear-Coupled Flow Instabilities and Their Effects on Dryout
M. Ishii; X. Sunn; S. Kuran
2004-09-27
Nuclear-coupled flow/power oscillations in boiling water reactors (BWRs) are investigated experimentally and analytically. A detailed literature survey is performed to identify and classify instabilities in two-phase flow systems. The classification and the identification of the leading physical mechanisms of the two-phase flow instabilities are important to propose appropriate analytical models and scaling criteria for simulation. For the purpose of scaling and the analysis of the nonlinear aspects of the coupled flow/power oscillations, an extensive analytical modeling strategy is developed and used to derive both frequency and time domain analysis tools.
Weber, Daniel; Albella, Pablo; Alonso-González, Pablo; Neubrech, Frank; Gui, Han; Nagao, Tadaaki; Hillenbrand, Rainer; Aizpurua, Javier; Pucci, Annemarie
2011-08-01
Interaction between micrometer-long nanoantennas within an array considerably modifies the plasmonic resonant behaviour; for fundamental resonances in the infrared already at micrometer distances. In order to get systematic knowledge on the relationship between infrared plasmonic resonances and separation distances dx and dy in longitudinal and transverse direction, respectively, we experimentally studied the optical extinction spectra for rectangularly ordered lithographic gold nanorod arrays on silicon wafers. For small dy, strong broadening of resonances and strongly decreased values of far-field extinction are detected which come along with a decreased near-field intensity, as indicated by near-field amplitude maps of the interacting nanoantennas. In contrast, near-field interaction over small dx does only marginally broaden the resonance. Our findings set a path for optimum design of rectangular nanorod lattices for surface enhanced infrared spectroscopy. PMID:21934866
Carbonari, S.; Dezi, F.; Leoni, G.
2008-07-08
This paper presents a study on the seismic response of coupled wall-frame structures founded on piles. A complete soil-structure interaction analysis is carried out with reference to a case study. Three different soils and seven real accelerograms are considered. Local site response analyses are performed in order to evaluate the incoming free-field motion at different depths and the ground motion amplifications. A numerical model, accounting for the pile-soil-pile interaction and for material and radiation damping, is used to evaluate the impedance matrix and the foundation input motion. The domain decomposition technique is adopted to perform time-domain seismic analyses introducing Lumped Parameter Models to take into account the impedance of the soil-structure system. Applications show that the rocking phenomena affect the behaviour of the structure by changing the base shear distribution within the wall and the frame and by increasing the structural displacements.
Manipulating effective spin orbit coupling based on proximity effect in magnetic bilayers
Zhang, Y. Q.; Sun, N. Y.; Che, W. R.; Zhang, J. W.; Shan, R.; Li, X. L.; Zhu, Z. G. Su, G.
2015-08-24
A proximity effect of spin orbit coupling (SOC) is proposed in nonmagnetic metal/ferromagnet (NM/FM) bilayers by extending the Crépieux-Bruno (CB) theory. We demonstrate that over 1000% enhancement of the SOC strength can be realized based on this effect (Pt/FM bilayers) and it brings greatly enhanced anomalous Hall effect and anomalous Nernst effect. This work could help maximize the performance of magnetic transport property for the spintronics device using NM/FM as the key structure.
Dendritic and synaptic effects in systems of coupled cortical oscillators.
Crook, S M; Ermentrout, G B; Bower, J M
1998-07-01
We explore the influence of synaptic location and form on the behavior of networks of coupled cortical oscillators. First, we develop a model of two coupled somatic oscillators that includes passive dendritic cables. Using a phase model approach, we show that the synchronous solution can change from a stable solution to an unstable one as the cable lengthens and the synaptic position moves further from the soma. We confirm this prediction using a system of coupled compartmental models. We also demonstrate that when the synchronous solution becomes unstable, a bifurcation occurs and a pair of asynchronous stable solutions appear, causing a phase lag between the cells in the system. Then using a variety of coupling functions and different synaptic positions, we show that distal connections and broad synaptic time courses encourage phase lags that can be reduced, eliminated, or enhanced by the presence of active currents in the dendrite. This mechanism may appear in neural systems where proximal connections could be used to encourage synchrony, and distal connections and broad synaptic time courses could be used to produce phase lags that can be modulated by active currents.
Tal, Ofir; Trabelcy, Beny; Gerchman, Yoram; Adir, Noam
2014-01-01
The phycobilisome (PBS) is an extremely large light-harvesting complex, common in cyanobacteria and red algae, composed of rods and core substructures. These substructures are assembled from chromophore-bearing phycocyanin and allophycocyanin subunits, nonpigmented linker proteins and in some cases additional subunits. To date, despite the determination of crystal structures of isolated PBS components, critical questions regarding the interaction and energy flow between rods and core are still unresolved. Additionally, the arrangement of minor PBS components located inside the core cylinders is unknown. Different models of the general architecture of the PBS have been proposed, based on low resolution images from electron microscopy or high resolution crystal structures of isolated components. This work presents a model of the assembly of the rods onto the core arrangement and for the positions of inner core components, based on cross-linking and mass spectrometry analysis of isolated, functional intact Thermosynechococcus vulcanus PBS, as well as functional cross-linked adducts. The experimental results were utilized to predict potential docking interactions of different protein pairs. Combining modeling and cross-linking results, we identify specific interactions within the PBS subcomponents that enable us to suggest possible functional interactions between the chromophores of the rods and the core and improve our understanding of the assembly, structure, and function of PBS. PMID:25296757
ERIC Educational Resources Information Center
Taht, Kadri; Mills, Melinda
2012-01-01
Many children live in households where either one or both parents work nonstandard schedules in the evening, night, or weekend. This study tests two competing hypotheses of whether nonstandard schedules result in lower levels of parent-child interaction or in more time with children. Using the first wave of the Netherlands Kinship Panel Study of…
Mesoscale dynamic coupling of finite- and discrete-element methods for fluid-particle interactions.
Srivastava, S; Yazdchi, K; Luding, S
2014-08-01
A new method for two-way fluid-particle coupling on an unstructured mesoscopically coarse mesh is presented. In this approach, we combine a (higher order) finite-element method (FEM) on the moving mesh for the fluid with a soft sphere discrete-element method for the particles. The novel feature of the proposed scheme is that the FEM mesh is a dynamic Delaunay triangulation based on the positions of the moving particles. Thus, the mesh can be multi-purpose: it provides (i) a framework for the discretization of the Navier-Stokes equations, (ii) a simple tool for detecting contacts between moving particles, (iii) a basis for coarse-graining or upscaling, and (iv) coupling with other physical fields (temperature, electromagnetic, etc.). This approach is suitable for a wide range of dilute and dense particulate flows, because the mesh resolution adapts with particle density in a given region. Two-way momentum exchange is implemented using semi-empirical drag laws akin to other popular approaches; for example, the discrete particle method, where a finite-volume solver on a coarser, fixed grid is used. We validate the methodology with several basic test cases, including single- and double-particle settling with analytical and empirical expectations, and flow through ordered and random porous media, when compared against finely resolved FEM simulations of flow through fixed arrays of particles. PMID:24982251
Coupled interactions of organized deep convection over the tropical western pacific
Hong, X.; Raman, S.
1996-04-01
The relationship between sea surface temperature (SST) and deep convection is complex. In general, deep convection occurs more frequently and with more intensity as SSTs become higher. This theory assumes that the atmospheric stability is sufficiently reduced to allow the onset of moist convection. However, the amount and intensity of convection observed tends to decrease with increasing SST because very warm SSTs. A reason for such decrease is the enhancements to surface fluxes of heat and moisture out of the ocean surface because of the vertical overturning associated with deep convection. Early studies used the radiative-convective models of the atmosphere to examine the role of the convective exchange of heat and moisture in maintaining the vertical temperature profile. In this paper we use a Coupled Ocean/Atmosphere Mesoscale Prediction System (COAMPS) to simulate a squall line over a tropical ocean global atmosphere/coupled ocean atmosphere response experiment (TOGA/COARE) area and to investigate how the ocean cooling mechanisms associated with organized deep convection act to limit tropical SSTs.
NASA Astrophysics Data System (ADS)
Walters, David; Moore, Laura J.; Duran Vinent, Orencio; Fagherazzi, Sergio; Mariotti, Giulio
2014-09-01
Interactions between backbarrier marshes and barrier islands will likely play an important role in determining how low-lying coastal systems respond to sea level rise and changes in storminess in the future. To assess the role of couplings between marshes and barrier islands under changing conditions, we develop and apply a coupled barrier island-marsh model (GEOMBEST+) to assess the impact of overwash deposition on backbarrier marsh morphology and of marsh morphology on rates of island migration. Our model results suggest that backbarrier marsh width is in a constant state of change until either the backbarrier basin becomes completely filled or backbarrier marsh deposits have completely eroded away. Results also suggest that overwash deposition is an important source of sediment, which allows existing narrow marshes to be maintained in a long-lasting alternate state (~500 m wide in the Virginia Barrier Islands) within a range of conditions under which they would otherwise disappear. The existence of a narrow marsh state is supported by observations of backbarrier marshes along the eastern shore of Virginia. Additional results suggest that marshes reduce accommodation in the backbarrier bay, which, in turn, decreases island migration rate. As climate change results in sea level rise, and the increased potential for intense hurricanes resulting in overwash, it is likely that these couplings will become increasingly important in determining future system behavior.
Global effects of interactions on galaxy evolution
NASA Technical Reports Server (NTRS)
Kennicutt, Robert C., Jr.
1990-01-01
Recent observations of the evolutionary properties of paired and interacting galaxies are reviewed, with special emphasis on their global emission properties and star formation rates. Data at several wavelengths provide strong confirmation of the hypothesis, proposed originally by Larson and Tinsley, that interactions trigger global bursts of star formation in galaxies. The nature and properties of the starbursts, and their overall role in galactic evolution are also discussed.
Ayabe, Kazuki; Sato, Kazunobu; Nishida, Shinsuke; Ise, Tomoaki; Nakazawa, Shigeaki; Sugisaki, Kenji; Morita, Yasushi; Toyota, Kazuo; Shiomi, Daisuke; Kitagawa, Masahiro; Takui, Takeji
2012-07-01
Weakly exchange-coupled biradicals have attracted much attention in terms of their DNP application in NMR spectroscopy for biological systems or the use of synthetic electron-spin qubits. Pulse-ESR based electron spin nutation (ESN) spectroscopy applied to biradicals is generally treated as transition moment spectroscopy from the theoretical side, illustrating that it is a powerful and facile tool to determine relatively short distances between weakly exchange-coupled electron spins. The nutation frequency as a function of the microwave irradiation strength ω(1) (angular frequency) for any cases of weakly exchange-coupled systems can be classified into three categories; D(12) (spin dipolar interaction)-driven, Δg-driven and ω(1)-driven nutation behaviour with the increasing strength of ω(1). For hetero-spin biradicals, Δg effects can be a dominating characteristic in the biradical nutation spectroscopy. Two-dimensional pulse-based electron spin nutation (2D-ESN) spectroscopy operating at the X-band can afford to determine small values of D(12) in weakly exchange-coupled biradicals in rigid glasses. The analytical expressions derived here for ω(1)-dependent nutation frequencies are based on only four electronic spin states relevant to the biradicals, while real biradical systems often have sizable hyperfine interactions. Thus, we have evaluated nuclear hyperfine effects on the nutation frequencies to check the validity of the present theoretical treatment. The experimental spin dipolar coupling of a typical TEMPO-based biradical 1, (2,2,6,6-tetra[((2)H(3))methyl]-[3,3-(2)H(2),4-(2)H(1),5,5-(2)H(2)]piperidin-N-oxyl-4-yl)(2,2,6,6-tetra[((2)H(3))methyl]-[3,3-(2)H(2),4-(2)H(1),5,5-(2)H(2),(15)N]piperidin-(15)N-oxyl-4-yl) terephthalate in a toluene glass, with a distance of 1.69 nm between the two spin sites is D(12) = -32 MHz (the effect of the exchange coupling J(12) is vanishing due to the homo-spin sites of 1, i.e.Δg = 0), while 0 < |J(12)|≦ 1.0 MHz as
NASA Astrophysics Data System (ADS)
Chen, Chen; Lu, Dan-Feng; Gao, Ran; Cheng, Jin; Qi, Zhi-Mei
2016-06-01
Evanescent-wave-coupled emission has been used for reverse Kretschmann fluorescence and Raman spectroscopies with high collection efficiency. However, it has a negative effect on the common surface-enhanced Raman spectroscopy and tip-enhanced Raman spectroscopy without the reverse Kretschmann configuration because the coupling of a large fraction of light power into the substrate impairs the Raman signal backscattered in air. A rough core layer can significantly weaken evanescent-wave-coupled emission, which is conducive to enhancing the backscattered Raman signal. In this work, we theoretically investigate the surface-plasmon-coupled emission and its effects on surface Raman spectroscopy.
Extrinsic spin Hall effect from anisotropic Rashba spin-orbit coupling in graphene
NASA Astrophysics Data System (ADS)
Yang, H.-Y.; Huang, Chunli; Ochoa, H.; Cazalilla, M. A.
2016-02-01
We study the effect of anisotropy of the Rashba coupling on the extrinsic spin Hall effect due to spin-orbit active adatoms on graphene. In addition to the intrinsic spin-orbit coupling, a generalized anisotropic Rashba coupling arising from the breakdown of both mirror and hexagonal symmetries of pristine graphene is considered. We find that Rashba anisotropy can strongly modify the dependence of the spin Hall angle on carrier concentration. Our model provides a simple and general description of the skew scattering mechanism due to the spin-orbit coupling that is induced by proximity to large adatom clusters.
Effects of Soft Electron Precipitation on the Coupled Magnetosphere-Ionosphere-Thermosphere
NASA Astrophysics Data System (ADS)
Zhang, B.; Lotko, W.; Brambles, O.; Wiltberger, M. J.; Wang, W.; Schmitt, P. J.; Lyon, J.
2011-12-01
Global simulations play an important role in understanding the coupled magnetosphere-ionosphere-thermosphere (MIT) system. The MIT interaction involves both electrodynamic and plasma transport processes, and it is influenced by precipitating particles that deposit both thermal and kinetic energy from the magnetosphere in the ionosphere-thermosphere. Currently, global simulation codes do not include soft electron precipitation, which can significantly influence the thermospheric and ionospheric structure. In this study, two types of causally specified soft electron precipitation, direct-entry cusp and broadband electron precipitation, are implemented in the Coupled Magnetosphere-Ionosphere-Thermosphere (CMIT) model. The direct entry cusp electron precipitation is modeled by specifying the electron thermal flux and temperature in a dynamically determined cusp area. The broadband electron precipitation is regulated by the downward Alfvenic Poynting flux based on empirical relations from Polar and FAST satellite data. Simulation results show that while both types of soft electron precipitation have only minor effects on the ionospheric conductance, they can significantly modify the plasma distribution in the F-region ionosphere and the neutral density in the thermosphere.
Probing top quark neutral couplings in the Standard Model Effective Field Theory at NLO in QCD
NASA Astrophysics Data System (ADS)
Bylund, Olga Bessidskaia; Maltoni, Fabio; Tsinikos, Ioannis; Vryonidou, Eleni; Zhang, Cen
2016-05-01
Top quark pair production in association with a Z-boson or a photon at the LHC directly probes neutral top-quark couplings. We present predictions for these two processes in the Standard Model (SM) Effective Field Theory (EFT) at next-to-leading order (NLO) in QCD. We include the full set of CP-even dimension-six operators that enter the top-quark interactions with the SM gauge bosons. For comparison, we also present predictions in the SMEFT for top loop-induced HZ production at the LHC and for toverline{t} production at the ILC at NLO in QCD. Results for total cross sections and differential distributions are obtained and uncertainties coming from missing higher orders in the strong coupling and in the EFT expansions are discussed. NLO results matched to the parton shower are available, allowing for event generation to be directly employed in an experimental analyses. Our framework provides a solid basis for the interpretation of current and future measurements in the SMEFT, with improved accuracy and precision.
NASA Technical Reports Server (NTRS)
Rosenfield, J. E.; Douglass, A. R.
1999-01-01
The GSFC 2D interactive chemistry-radiation-dynamics model has been used to study the effects on stratospheric trace gases of past and future CO2 increases coupled with changes in CFC'S, methane, and nitrous oxide. Previous simulations with the GSFC model showed that the stratospheric cooling calculated to result from doubling atmospheric CO2 would lead, in the absence of a growth of other anthropogenic gases, to a decrease in upper stratospheric NO(y) of roughly 15%. This work has been extended to simulate changes in stratospheric chemistry and dynamics occurring between the years 1960 and 2050. The simulations have been carried out with and without changes in CO2. In the low latitude upper stratosphere ozone is predicted to be 10% greater in 2050 than in 1990 when increased CO2 is included, compared with an increase of only 2% without the inclusion of CO2. In the low latitude lower stratosphere, ozone is predicted to decrease by about 1% between 1990 and 2050 when CO2 changes are taken into account, in contrast to an approximate 3% increase when they are not. The simulated behavior of water vapor is another example of the coupled responses. Between 1990 and 2050 low latitude water vapor is predicted to increase by 4% and 2% in the upper and lower stratosphere, respectively, without the inclusion of CO2 increases. with the inclusion of CO2 changes, the water vapor increases are predicted to be roughly 12% and 8%, for the upper and lower stratosphere, respectively.
The Effects of Ecological Variables on Parent-Infant Interaction.
ERIC Educational Resources Information Center
Lamb, Michael E.
This paper summarizes the findings of a series of studies on the effects of "ecological variables" on mother-father-sibling-infant interactions. Under consideration were: (1) the effects of stress on the parental preferences of young infants; (2) the effects of the presence of one parent on the interactions within the other parent-infant dyad; (3)…
Curvature-enhanced Spin-orbit Coupling and Spinterface Effect in Fullerene-based Spin Valves
Liang, Shiheng; Geng, Rugang; Yang, Baishun; Zhao, Wenbo; Chandra Subedi, Ram; Li, Xiaoguang; Han, Xiufeng; Nguyen, Tho Duc
2016-01-01
We investigated curvature-enhanced spin-orbit coupling (SOC) and spinterface effect in carbon-based organic spin valves (OSVs) using buckyball C60 and C70 molecules. Since the naturally abundant 12C has spinless nuclear, the materials have negligible hyperfine interaction (HFI) and the same intrinsic SOC, but different curvature SOC due to their distinct curvatures. We fitted the thickness dependence of magnetoresistance (MR) in OSVs at various temperatures using the modified Jullière equation. We found that the spin diffusion length in the C70 film is above 120 nm, clearly longer than that in C60 film at all temperatures. The effective SOC ratio of the C70 film to the C60 film was estimated to be about 0.8. This was confirmed by the magneto-electroluminescence (MEL) measurement in fullerene-based light emitting diodes (LED). Next, the effective spin polarization in C70-based OSVs is smaller than that in C60-based OSVs implying that they have different spinterface effect. First principle calculation study shows that the spin polarization of the dz2 orbital electrons of Co atoms contacted with C60 is larger causing better effective spin polarization at the interface. PMID:26786047