Directional abnormalities of vestibular and optokinetic responses in cerebellar disease

NASA Technical Reports Server (NTRS)

Walker, M. F.; Zee, D. S.; Shelhamer, M. J. (Principal Investigator)

1999-01-01

Directional abnormalities of vestibular and optokinetic responses in patients with cerebellar degeneration are reported. Three-axis magnetic search-coil recordings of the eye and head were performed in eight cerebellar patients. Among these patients, examples of directional cross-coupling were found during (1) high-frequency, high-acceleration head thrusts; (2) constant-velocity chair rotations with the head fixed; (3) constant-velocity optokinetic stimulation; and (4) following repetitive head shaking. Cross-coupling during horizontal head thrusts consisted of an inappropriate upward eye-velocity component. In some patients, sustained constant-velocity yaw-axis chair rotations produced a mixed horizontal-torsional nystagmus and/or an increase in the baseline vertical slow-phase velocity. Following horizontal head shaking, some patients showed an increase in the slow-phase velocity of their downbeat nystagmus. These various forms of cross-coupling did not necessarily occur to the same degree in a given patient; this suggests that different mechanisms may be responsible. It is suggested that cross-coupling during head thrusts may reflect a loss of calibration of brainstem connections involved in the direct vestibular pathways, perhaps due to dysfunction of the flocculus. Cross-coupling during constant-velocity rotations and following head shaking may result from a misorientation of the angular eye-velocity vector in the velocity-storage system. Finally, responses to horizontal optokinetic stimulation included an inappropriate torsional component in some patients. This suggests that the underlying organization of horizontal optokinetic tracking is in labyrinthine coordinates. The findings are also consistent with prior animal-lesion studies that have shown a role for the vestibulocerebellum in the control of the direction of the VOR.

Collaborative simulation method with spatiotemporal synchronization process control

NASA Astrophysics Data System (ADS)

Zou, Yisheng; Ding, Guofu; Zhang, Weihua; Zhang, Jian; Qin, Shengfeng; Tan, John Kian

2016-10-01

When designing a complex mechatronics system, such as high speed trains, it is relatively difficult to effectively simulate the entire system's dynamic behaviors because it involves multi-disciplinary subsystems. Currently,a most practical approach for multi-disciplinary simulation is interface based coupling simulation method, but it faces a twofold challenge: spatial and time unsynchronizations among multi-directional coupling simulation of subsystems. A new collaborative simulation method with spatiotemporal synchronization process control is proposed for coupling simulating a given complex mechatronics system across multiple subsystems on different platforms. The method consists of 1) a coupler-based coupling mechanisms to define the interfacing and interaction mechanisms among subsystems, and 2) a simulation process control algorithm to realize the coupling simulation in a spatiotemporal synchronized manner. The test results from a case study show that the proposed method 1) can certainly be used to simulate the sub-systems interactions under different simulation conditions in an engineering system, and 2) effectively supports multi-directional coupling simulation among multi-disciplinary subsystems. This method has been successfully applied in China high speed train design and development processes, demonstrating that it can be applied in a wide range of engineering systems design and simulation with improved efficiency and effectiveness.

Fathers’ Involvement in Child Health Care: Associations with Prenatal Involvement, Parents’ Beliefs, and Maternal Gatekeeping

PubMed Central

Zvara, B.J.; Schoppe-Sullivan, Sarah J.; Dush, Claire M. Kamp

2015-01-01

Using data from 182 dual-earner couples experiencing the transition to parenthood, this study examined associations between prenatal involvement, gender role beliefs, and maternal gatekeeping and new fathers’ involvement in child health care. Results indicated that prenatal father involvement was associated with both fathers’ direct engagement in child health care and fathers’ perceived influence in child health-related decision-making. Fathers also demonstrated greater direct engagement in child health care when mothers held more nontraditional beliefs about gender roles. Moreover, when mothers were more encouraging of fathers’ involvement in childrearing, fathers felt more influential in child health-related decision-making, whereas when mothers engaged in greater gate closing behavior, fathers with more traditional gender role beliefs felt less influential in child health-related decision-making. This study suggests that fathers’ prenatal involvement, mothers’ beliefs, and maternal gatekeeping may play a role in the development of new fathers’ involvement in child health care at the transition to parenthood. PMID:26405366

System-wide hybrid MPC-PID control of a continuous pharmaceutical tablet manufacturing process via direct compaction.

PubMed

Singh, Ravendra; Ierapetritou, Marianthi; Ramachandran, Rohit

2013-11-01

The next generation of QbD based pharmaceutical products will be manufactured through continuous processing. This will allow the integration of online/inline monitoring tools, coupled with an efficient advanced model-based feedback control systems, to achieve precise control of process variables, so that the predefined product quality can be achieved consistently. The direct compaction process considered in this study is highly interactive and involves time delays for a number of process variables due to sensor placements, process equipment dimensions, and the flow characteristics of the solid material. A simple feedback regulatory control system (e.g., PI(D)) by itself may not be sufficient to achieve the tight process control that is mandated by regulatory authorities. The process presented herein comprises of coupled dynamics involving slow and fast responses, indicating the requirement of a hybrid control scheme such as a combined MPC-PID control scheme. In this manuscript, an efficient system-wide hybrid control strategy for an integrated continuous pharmaceutical tablet manufacturing process via direct compaction has been designed. The designed control system is a hybrid scheme of MPC-PID control. An effective controller parameter tuning strategy involving an ITAE method coupled with an optimization strategy has been used for tuning of both MPC and PID parameters. The designed hybrid control system has been implemented in a first-principles model-based flowsheet that was simulated in gPROMS (Process System Enterprise). Results demonstrate enhanced performance of critical quality attributes (CQAs) under the hybrid control scheme compared to only PID or MPC control schemes, illustrating the potential of a hybrid control scheme in improving pharmaceutical manufacturing operations. Copyright © 2013 Elsevier B.V. All rights reserved.

A fast direct solver for a class of two-dimensional separable elliptic equations on the sphere

NASA Technical Reports Server (NTRS)

Moorthi, Shrinivas; Higgins, R. Wayne

1992-01-01

An efficient, direct, second-order solver for the discrete solution of two-dimensional separable elliptic equations on the sphere is presented. The method involves a Fourier transformation in longitude and a direct solution of the resulting coupled second-order finite difference equations in latitude. The solver is made efficient by vectorizing over longitudinal wavenumber and by using a vectorized fast Fourier transform routine. It is evaluated using a prescribed solution method and compared with a multigrid solver and the standard direct solver from FISHPAK.

Non-invasive determination of glucose directly in raw fruits using a continuous flow system based on microdialysis sampling and amperometric detection at an integrated enzymatic biosensor.

PubMed

Vargas, E; Ruiz, M A; Campuzano, S; Reviejo, A J; Pingarrón, J M

2016-03-31

A non-destructive, rapid and simple to use sensing method for direct determination of glucose in non-processed fruits is described. The strategy involved on-line microdialysis sampling coupled with a continuous flow system with amperometric detection at an enzymatic biosensor. Apart from direct determination of glucose in fruit juices and blended fruits, this work describes for the first time the successful application of an enzymatic biosensor-based electrochemical approach to the non-invasive determination of glucose in raw fruits. The methodology correlates, through previous calibration set-up, the amperometric signal generated from glucose in non-processed fruits with its content in % (w/w). The comparison of the obtained results using the proposed approach in different fruits with those provided by other method involving the same commercial biosensor as amperometric detector in stirred solutions pointed out that there were no significant differences. Moreover, in comparison with other available methodologies, this microdialysis-coupled continuous flow system amperometric biosensor-based procedure features straightforward sample preparation, low cost, reduced assay time (sampling rate of 7 h(-1)) and ease of automation. Copyright © 2016 Elsevier B.V. All rights reserved.

On a stochastic control method for weakly coupled linear systems. M.S. Thesis

NASA Technical Reports Server (NTRS)

Kwong, R. H.

1972-01-01

The stochastic control of two weakly coupled linear systems with different controllers is considered. Each controller only makes measurements about his own system; no information about the other system is assumed to be available. Based on the noisy measurements, the controllers are to generate independently suitable control policies which minimize a quadratic cost functional. To account for the effects of weak coupling directly, an approximate model, which involves replacing the influence of one system on the other by a white noise process is proposed. Simple suboptimal control problem for calculating the covariances of these noises is solved using the matrix minimum principle. The overall system performance based on this scheme is analyzed as a function of the degree of intersystem coupling.

Room-temperature coupling between electrical current and nuclear spins in OLEDs

NASA Astrophysics Data System (ADS)

Malissa, H.; Kavand, M.; Waters, D. P.; van Schooten, K. J.; Burn, P. L.; Vardeny, Z. V.; Saam, B.; Lupton, J. M.; Boehme, C.

2014-09-01

The effects of external magnetic fields on the electrical conductivity of organic semiconductors have been attributed to hyperfine coupling of the spins of the charge carriers and hydrogen nuclei. We studied this coupling directly by implementation of pulsed electrically detected nuclear magnetic resonance spectroscopy in organic light-emitting diodes (OLEDs). The data revealed a fingerprint of the isotope (protium or deuterium) involved in the coherent spin precession observed in spin-echo envelope modulation. Furthermore, resonant control of the electric current by nuclear spin orientation was achieved with radiofrequency pulses in a double-resonance scheme, implying current control on energy scales one-millionth the magnitude of the thermal energy.

Universal Stabilization of a Parametrically Coupled Qubit

NASA Astrophysics Data System (ADS)

Lu, Yao; Chakram, S.; Leung, N.; Earnest, N.; Naik, R. K.; Huang, Ziwen; Groszkowski, Peter; Kapit, Eliot; Koch, Jens; Schuster, David I.

2017-10-01

We autonomously stabilize arbitrary states of a qubit through parametric modulation of the coupling between a fixed frequency qubit and resonator. The coupling modulation is achieved with a tunable coupling design, in which the qubit and the resonator are connected in parallel to a superconducting quantum interference device. This allows for quasistatic tuning of the qubit-cavity coupling strength from 12 MHz to more than 300 MHz. Additionally, the coupling can be dynamically modulated, allowing for single-photon exchange in 6 ns. Qubit coherence times exceeding 20 μ s are maintained over the majority of the range of tuning, limited primarily by the Purcell effect. The parametric stabilization technique realized using the tunable coupler involves engineering the qubit bath through a combination of photon nonconserving sideband interactions realized by flux modulation, and direct qubit Rabi driving. We demonstrate that the qubit can be stabilized to arbitrary states on the Bloch sphere with a worst-case fidelity exceeding 80%.

Direct quantitative detection of Doc2b-induced hemifusion in optically trapped membranes

NASA Astrophysics Data System (ADS)

Brouwer, Ineke; Giniatullina, Asiya; Laurens, Niels; van Weering, Jan R. T.; Bald, Dirk; Wuite, Gijs J. L.; Groffen, Alexander J.

2015-09-01

Ca2+-sensor proteins control the secretion of many neuroendocrine substances. Calcium-secretion coupling may involve several mechanisms. First, Ca2+-dependent association of their tandem C2 domains with phosphatidylserine may induce membrane curvature and thereby enhance fusion. Second, their association with SNARE complexes may inhibit membrane fusion in the absence of a Ca2+ trigger. Here we present a method using two optically trapped beads coated with SNARE-free synthetic membranes to elucidate the direct role of the C2AB domain of the soluble Ca2+-sensor Doc2b. Contacting membranes are often coupled by a Doc2b-coated membrane stalk that resists forces up to 600 pN upon bead separation. Stalk formation depends strictly on Ca2+ and phosphatidylserine. Real-time fluorescence imaging shows phospholipid but not content mixing, indicating membrane hemifusion. Thus, Doc2b acts directly on membranes and stabilizes the hemifusion intermediate in this cell-free system. In living cells, this mechanism may co-occur with progressive SNARE complex assembly, together defining Ca2+-secretion coupling.

G protein-coupled receptor kinase 2 positively regulates epithelial cell migration

PubMed Central

Penela, Petronila; Ribas, Catalina; Aymerich, Ivette; Eijkelkamp, Niels; Barreiro, Olga; Heijnen, Cobi J; Kavelaars, Annemieke; Sánchez-Madrid, Francisco; Mayor, Federico

2008-01-01

Cell migration requires integration of signals arising from both the extracellular matrix and messengers acting through G protein-coupled receptors (GPCRs). We find that increased levels of G protein-coupled receptor kinase 2 (GRK2), a key player in GPCR regulation, potentiate migration of epithelial cells towards fibronectin, whereas such process is decreased in embryonic fibroblasts from hemizygous GRK2 mice or upon knockdown of GRK2 expression. Interestingly, the GRK2 effect on fibronectin-mediated cell migration involves the paracrine/autocrine activation of a sphingosine-1-phosphate (S1P) Gi-coupled GPCR. GRK2 positively modulates the activity of the Rac/PAK/MEK/ERK pathway in response to adhesion and S1P by a mechanism involving the phosphorylation-dependent, dynamic interaction of GRK2 with GIT1, a key scaffolding protein in cell migration processes. Furthermore, decreased GRK2 levels in hemizygous mice result in delayed wound healing rate in vivo, consistent with a physiological role of GRK2 as a regulator of coordinated integrin and GPCR-directed epithelial cell migration. PMID:18369319

Directional emission from dye-functionalized plasmonic DNA superlattice microcavities

PubMed Central

Park, Daniel J.; Ku, Jessie C.; Sun, Lin; Lethiec, Clotilde M.; Stern, Nathaniel P.; Schatz, George C.; Mirkin, Chad A.

2017-01-01

Three-dimensional plasmonic superlattice microcavities, made from programmable atom equivalents comprising gold nanoparticles functionalized with DNA, are used as a testbed to study directional light emission. DNA-guided nanoparticle colloidal crystallization allows for the formation of micrometer-scale single-crystal body-centered cubic gold nanoparticle superlattices, with dye molecules coupled to the DNA strands that link the particles together, in the form of a rhombic dodecahedron. Encapsulation in silica allows one to create robust architectures with the plasmonically active particles and dye molecules fixed in space. At the micrometer scale, the anisotropic rhombic dodecahedron crystal habit couples with photonic modes to give directional light emission. At the nanoscale, the interaction between the dye dipoles and surface plasmons can be finely tuned by coupling the dye molecules to specific sites of the DNA particle-linker strands, thereby modulating dye–nanoparticle distance (three different positions are studied). The ability to control dye position with subnanometer precision allows one to systematically tune plasmon–excition interaction strength and decay lifetime, the results of which have been supported by electrodynamics calculations that span length scales from nanometers to micrometers. The unique ability to control surface plasmon/exciton interactions within such superlattice microcavities will catalyze studies involving quantum optics, plasmon laser physics, strong coupling, and nonlinear phenomena. PMID:28053232

Direct current superconducting quantum interference device spectrometer for pulsed nuclear magnetic resonance and nuclear quadrupole resonance at frequencies up to 5 MHz

DOE Office of Scientific and Technical Information (OSTI.GOV)

TonThat, D.M.; Clarke, J.

1996-08-01

A spectrometer based on a dc superconducting quantum interference device (SQUID) has been developed for the direct detection of nuclear magnetic resonance (NMR) or nuclear quadrupole resonance (NQR) at frequencies up to 5 MHz. The sample is coupled to the input coil of the niobium-based SQUID via a nonresonant superconducting circuit. The flux locked loop involves the direct offset integration technique with additional positive feedback in which the output of the SQUID is coupled directly to a low-noise preamplifier. Precession of the nuclear quadrupole spins is induced by a magnetic field pulse with the feedback circuit disabled; subsequently, flux lockedmore » operation is restored and the SQUID amplifies the signal produced by the nuclear free induction signal. The spectrometer has been used to detect {sup 27}Al NQR signals in ruby (Al{sub 2}O{sub 3}[Cr{sup 3+}]) at 359 and 714 kHz. {copyright} {ital 1996 American Institute of Physics.}« less

System Simulation by Recursive Feedback: Coupling a Set of Stand-Alone Subsystem Simulations

NASA Technical Reports Server (NTRS)

Nixon, D. D.

2001-01-01

Conventional construction of digital dynamic system simulations often involves collecting differential equations that model each subsystem, arran g them to a standard form, and obtaining their numerical gin solution as a single coupled, total-system simultaneous set. Simulation by numerical coupling of independent stand-alone subsimulations is a fundamentally different approach that is attractive because, among other things, the architecture naturally facilitates high fidelity, broad scope, and discipline independence. Recursive feedback is defined and discussed as a candidate approach to multidiscipline dynamic system simulation by numerical coupling of self-contained, single-discipline subsystem simulations. A satellite motion example containing three subsystems (orbit dynamics, attitude dynamics, and aerodynamics) has been defined and constructed using this approach. Conventional solution methods are used in the subsystem simulations. Distributed and centralized implementations of coupling have been considered. Numerical results are evaluated by direct comparison with a standard total-system, simultaneous-solution approach.

RPA binds histone H3-H4 and functions in DNA replication-coupled nucleosome assembly.

PubMed

Liu, Shaofeng; Xu, Zhiyun; Leng, He; Zheng, Pu; Yang, Jiayi; Chen, Kaifu; Feng, Jianxun; Li, Qing

2017-01-27

DNA replication-coupled nucleosome assembly is essential to maintain genome integrity and retain epigenetic information. Multiple involved histone chaperones have been identified, but how nucleosome assembly is coupled to DNA replication remains elusive. Here we show that replication protein A (RPA), an essential replisome component that binds single-stranded DNA, has a role in replication-coupled nucleosome assembly. RPA directly binds free H3-H4. Assays using a synthetic sequence that mimics freshly unwound single-stranded DNA at replication fork showed that RPA promotes DNA-(H3-H4) complex formation immediately adjacent to double-stranded DNA. Further, an RPA mutant defective in H3-H4 binding exhibited attenuated nucleosome assembly on nascent chromatin. Thus, we propose that RPA functions as a platform for targeting histone deposition to replication fork, through which RPA couples nucleosome assembly with ongoing DNA replication. Copyright © 2017, American Association for the Advancement of Science.

Trend‐Analysis of Solid‐State Structures: Low‐Energy Conformational ‘Reactions’ Involving Directed and Coupled Movements in Half‐Sandwich Compounds [CpFe(CO){C(=O)R}PPh3

PubMed Central

2018-01-01

Abstract Trends in solid‐state structures were used to identify preferred intramolecular movements in half‐sandwich compounds [CpFe(CO){C(=O)R}PPh3]. Three weak interactions were analyzed: 1) the CH/π donor–acceptor interaction of phenyl rings in the PPh3 ligand, 2) the PhPPh3 face‐on Cp stabilization, and 3) the hydrogen bond between the oxygen atom of the acyl group and an ortho‐C−H bond of one of the PPh3 phenyl rings. Clockwise and counter‐clockwise rotations established directed and coupled movements of the PPh3 ligand, the acyl group, and the phenyl rings within the PPh3 ligand. PMID:29744282

Application of fast Fourier transforms to the direct solution of a class of two-dimensional separable elliptic equations on the sphere

NASA Technical Reports Server (NTRS)

Moorthi, Shrinivas; Higgins, R. W.

1993-01-01

An efficient, direct, second-order solver for the discrete solution of a class of two-dimensional separable elliptic equations on the sphere (which generally arise in implicit and semi-implicit atmospheric models) is presented. The method involves a Fourier transformation in longitude and a direct solution of the resulting coupled second-order finite-difference equations in latitude. The solver is made efficient by vectorizing over longitudinal wave-number and by using a vectorized fast Fourier transform routine. It is evaluated using a prescribed solution method and compared with a multigrid solver and the standard direct solver from FISHPAK.

Murai Reaction on Furfural Derivatives Enabled by Removable N,N'-Bidentate Directing Groups.

PubMed

Pezzetta, Cristofer; Veiros, Luis F; Oble, Julie; Poli, Giovanni

2017-06-22

Furfural and related compounds are industrially relevant building blocks obtained from lignocellulosic biomass. To enhance the added value of these renewable resources, a Ru-catalyzed hydrofurylation of alkenes, involving a directed C-H activation at C3 of the furan ring, was developed. A thorough experimental study revealed that a bidentate amino-imine directing group enabled the desired coupling. Removal of the directing group occurred during the purification step, directly releasing the C3-functionalized furfurals. Development of the reaction as well as optimization and scope of the method were described. A mechanism was proposed on the basis of DFT calculations. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Transport properties of elastically coupled fractional Brownian motors

NASA Astrophysics Data System (ADS)

Lv, Wangyong; Wang, Huiqi; Lin, Lifeng; Wang, Fei; Zhong, Suchuan

2015-11-01

Under the background of anomalous diffusion, which is characterized by the sub-linear or super-linear mean-square displacement in time, we proposed the coupled fractional Brownian motors, in which the asymmetrical periodic potential as ratchet is coupled mutually with elastic springs, and the driving source is the external harmonic force and internal thermal fluctuations. The transport mechanism of coupled particles in the overdamped limit is investigated as the function of the temperature of baths, coupling constant and natural length of the spring, the amplitude and frequency of driving force, and the asymmetry of ratchet potential by numerical stimulations. The results indicate that the damping force involving the information of historical velocity leads to the nonlocal memory property and blocks the traditional dissipative motion behaviors, and it even plays a cooperative role of driving force in drift motion of the coupled particles. Thus, we observe various non-monotonic resonance-like behaviors of collective directed transport in the mediums with different diffusion exponents.

The construction of a model of the process of couples' forgiveness in emotion-focused therapy for couples.

PubMed

Meneses, Catalina Woldarsky; Greenberg, Leslie S

2011-10-01

This study explored how forgiveness unfolds in the context of emotion-focused couples therapy (EFT-C) in eight cases of women betrayed by their partners. Forgiveness was defined as a process involving the reduction in negative feelings and the giving out of undeserved compassion. This was measured by changes in the pre- and posttreatment scores on the Enright Forgiveness Inventory, the Unfinished Business Resolution Scale, and a single item directly asking respondents to indicate their degree of forgiveness. A task analysis was performed to rigorously track the steps leading to forgiveness using videotapes of therapy sessions for eight couples. The performance of the four couples who forgave were compared with each other and then contrasted with the performance of another four couples who did not reach forgiveness at the end of therapy. Based on these observations, a model of the process of forgiveness in EFT-C and a process rating system were developed. © 2011 American Association for Marriage and Family Therapy.

Direct coupling between stress, strain and adsorption reactions - A study on coal-CO2 systems

NASA Astrophysics Data System (ADS)

Hol, S.; Peach, C. J.; Spiers, C. J.

2012-12-01

Though it is well-known that adsorption reactions frequently assist deformation of porous rocks, very little understanding exists on the direct coupling with stress state and strain. One of the materials in which adsorption plays a large role is coal, as is observed in the particular case of Enhanced Coalbed Methane Production (ECBM), which involves the geological storage of CO2 and the recovery of CH4. In this case, adsorption and the associated swelling cause significant injectivity problems, which is experienced in almost all pilot field projects to date. This suggests that indeed a strong fundamental coupling exists between CO2 sorption, changes in the mechanical state of the coal matrix and changes in the transport properties of the system, and illustrates the need to understand coupled stress-strain-sorption behaviour. In this contribution, we describe several important observations made on coal-CO2 systems that can learn us about many other natural, stressed adsorbate-adsorbent systems. In our experiments, first of all, the adsorption of CO2 in the coal matrix gave rise to swelling. Although this is well-known, we found that the total volumetric strain occurring under unconfined conditions can be realistically modelled (up to at least 100 MPa) as the sum of an adsorption-related expansion term and an elastic compression term. Second, effective in situ stresses will directly reduce the sorption capacity, and associated swelling of the coal matrix significantly. Our general thermodynamic model for the effect of a 3D stress state on adsorbed CO2 concentration supports this observation, and also shows that "self-stressing", as a result of CO2 adsorption occurring under conditions of restricted or zero strain (i.e. fully constrained conditions), will more than double the expected in situ stresses. A constitutive equation was developed to describe the full coupling between stress state, total strain (i.e. combined strain of adsorption processes and poroelasticity) and sorption, and was found to be consistent with experimental data. Third, it was observed that microfractures form in coal due to exposure to CO2 under unconfined conditions, which illustrates the potentially high forces and the large thermodynamic work term involved in adsorption reactions. The findings of this study all lead to the conclusion that direct effects of stress can have a considerable impact on adsorption processes. If this is the case for coal, also other adsorbate-rock interactions (e.g. clay-fluids in shale formations and deep fault rocks) may be subject to such a coupling. We believe that this topic deserved attention in future research.

The Fitness Effects of Men's Family Investments : A Test of Three Pathways in a Single Population.

PubMed

Winking, Jeffrey; Koster, Jeremy

2015-09-01

Men's investments in parenting and long-term reproductive relationships are a hallmark feature of human reproduction and life history. The uniqueness of such male involvement among catarrhines has driven an extensive debate surrounding the selective pressures that led to and maintain such capacities in men. Three major pathways have been proposed through which men's involvement might confer fitness benefits: enhancing child well-being, increasing couple fertility, and decreasing likelihood of partner desertion. Previous research has explored the impact of father involvement on these factors individually, but here we present novel research that explores all three pathways within the same population, the Mayangna/Miskito horticulturalists of Nicaragua. Furthermore, we expand the traditional dichotomous measure of father presence/absence by using a continuous measure of overall male investment, as well as two continuous measures of its subcomponents: direct care and wealth. We find that men's investments are associated with children's growth and possibly with wife's marital satisfaction; however, they are not associated with couple fertility.

Microbiologically Influenced Corrosion

DTIC Science & Technology

2009-01-01

related directly to the biomineralized deposits on the surface. Ennoble- ment in marine waters has been attributed to depolarization of the oxygen... abiotic ally oxi- dized metal precipitates, and still others that derive energy by oxidizing metals. Manganese. Manganese oxidation is coupled to cell...circumstances, pitting involves the conventional features of differential aeration, a large cathode: anode surface area, and the development of

Magnitude of finite-nucleus-size effects in relativistic density functional computations of indirect NMR nuclear spin-spin coupling constants.

PubMed

Autschbach, Jochen

2009-09-14

A spherical Gaussian nuclear charge distribution model has been implemented for spin-free (scalar) and two-component (spin-orbit) relativistic density functional calculations of indirect NMR nuclear spin-spin coupling (J-coupling) constants. The finite nuclear volume effects on the hyperfine integrals are quite pronounced and as a consequence they noticeably alter coupling constants involving heavy NMR nuclei such as W, Pt, Hg, Tl, and Pb. Typically, the isotropic J-couplings are reduced in magnitude by about 10 to 15 % for couplings between one of the heaviest NMR nuclei and a light atomic ligand, and even more so for couplings between two heavy atoms. For a subset of the systems studied, viz. the Hg atom, Hg(2) (2+), and Tl--X where X=Br, I, the basis set convergence of the hyperfine integrals and the coupling constants was monitored. For the Hg atom, numerical and basis set calculations of the electron density and the 1s and 6s orbital hyperfine integrals are directly compared. The coupling anisotropies of TlBr and TlI increase by about 2 % due to finite-nucleus effects.

Blood Stage Plasmodium falciparum Exhibits Biological Responses to Direct Current Electric Fields

PubMed Central

Coronado, Lorena M.; Montealegre, Stephania; Chaverra, Zumara; Mojica, Luis; Espinosa, Carlos; Almanza, Alejandro; Correa, Ricardo; Stoute, José A.; Gittens, Rolando A.

2016-01-01

The development of resistance to insecticides by the vector of malaria and the increasingly faster appearance of resistance to antimalarial drugs by the parasite can dangerously hamper efforts to control and eradicate the disease. Alternative ways to treat this disease are urgently needed. Here we evaluate the in vitro effect of direct current (DC) capacitive coupling electrical stimulation on the biology and viability of Plasmodium falciparum. We designed a system that exposes infected erythrocytes to different capacitively coupled electric fields in order to evaluate their effect on P. falciparum. The effect on growth of the parasite, replication of DNA, mitochondrial membrane potential and level of reactive oxygen species after exposure to electric fields demonstrate that the parasite is biologically able to respond to stimuli from DC electric fields involving calcium signaling pathways. PMID:27537497

Blood Stage Plasmodium falciparum Exhibits Biological Responses to Direct Current Electric Fields.

PubMed

Coronado, Lorena M; Montealegre, Stephania; Chaverra, Zumara; Mojica, Luis; Espinosa, Carlos; Almanza, Alejandro; Correa, Ricardo; Stoute, José A; Gittens, Rolando A; Spadafora, Carmenza

2016-01-01

The development of resistance to insecticides by the vector of malaria and the increasingly faster appearance of resistance to antimalarial drugs by the parasite can dangerously hamper efforts to control and eradicate the disease. Alternative ways to treat this disease are urgently needed. Here we evaluate the in vitro effect of direct current (DC) capacitive coupling electrical stimulation on the biology and viability of Plasmodium falciparum. We designed a system that exposes infected erythrocytes to different capacitively coupled electric fields in order to evaluate their effect on P. falciparum. The effect on growth of the parasite, replication of DNA, mitochondrial membrane potential and level of reactive oxygen species after exposure to electric fields demonstrate that the parasite is biologically able to respond to stimuli from DC electric fields involving calcium signaling pathways.

Detailed Characterization of Nearshore Processes During NCEX

NASA Astrophysics Data System (ADS)

Holland, K.; Kaihatu, J. M.; Plant, N.

2004-12-01

Recent technology advances have allowed the coupling of remote sensing methods with advanced wave and circulation models to yield detailed characterizations of nearshore processes. This methodology was demonstrated as part of the Nearshore Canyon EXperiment (NCEX) in La Jolla, CA during Fall 2003. An array of high-resolution, color digital cameras was installed to monitor an alongshore distance of nearly 2 km out to depths of 25 m. This digital imagery was analyzed over the three-month period through an automated process to produce hourly estimates of wave period, wave direction, breaker height, shoreline position, sandbar location, and bathymetry at numerous locations during daylight hours. Interesting wave propagation patterns in the vicinity of the canyons were observed. In addition, directional wave spectra and swash / surf flow velocities were estimated using more computationally intensive methods. These measurements were used to provide forcing and boundary conditions for the Delft3D wave and circulation model, giving additional estimates of nearshore processes such as dissipation and rip currents. An optimal approach for coupling these remotely sensed observations to the numerical model was selected to yield accurate, but also timely characterizations. This involved assimilation of directional spectral estimates near the offshore boundary to mimic forcing conditions achieved under traditional approaches involving nested domains. Measurements of breaker heights and flow speeds were also used to adaptively tune model parameters to provide enhanced accuracy. Comparisons of model predictions and video observations show significant correlation. As compared to nesting within larger-scale and coarser resolution models, the advantages of providing boundary conditions data using remote sensing is much improved resolution and fidelity. For example, rip current development was both modeled and observed. These results indicate that this approach to data-model coupling is tenable and may be useful in near-real-time characterizations required by many applied scenarios.

Observation of CH⋅⋅⋅π Interactions between Methyl and Carbonyl Groups in Proteins.

PubMed

Perras, Frédéric A; Marion, Dominique; Boisbouvier, Jérôme; Bryce, David L; Plevin, Michael J

2017-06-19

Protein structure and function is dependent on myriad noncovalent interactions. Direct detection and characterization of these weak interactions in large biomolecules, such as proteins, is experimentally challenging. Herein, we report the first observation and measurement of long-range "through-space" scalar couplings between methyl and backbone carbonyl groups in proteins. These J couplings are indicative of the presence of noncovalent C-H⋅⋅⋅π hydrogen-bond-like interactions involving the amide π network. Experimentally detected scalar couplings were corroborated by a natural bond orbital analysis, which revealed the orbital nature of the interaction and the origins of the through-space J couplings. The experimental observation of this type of CH⋅⋅⋅π interaction adds a new dimension to the study of protein structure, function, and dynamics by NMR spectroscopy. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Initialization and Predictability of a Coupled ENSO Forecast Model

NASA Technical Reports Server (NTRS)

Chen, Dake; Zebiak, Stephen E.; Cane, Mark A.; Busalacchi, Antonio J.

1997-01-01

The skill of a coupled ocean-atmosphere model in predicting ENSO has recently been improved using a new initialization procedure in which initial conditions are obtained from the coupled model, nudged toward observations of wind stress. The previous procedure involved direct insertion of wind stress observations, ignoring model feedback from ocean to atmosphere. The success of the new scheme is attributed to its explicit consideration of ocean-atmosphere coupling and the associated reduction of "initialization shock" and random noise. The so-called spring predictability barrier is eliminated, suggesting that such a barrier is not intrinsic to the real climate system. Initial attempts to generalize the nudging procedure to include SST were not successful; possible explanations are offered. In all experiments forecast skill is found to be much higher for the 1980s than for the 1970s and 1990s, suggesting decadal variations in predictability.

Radiant flux density, energy density, and fuel consumption in mixed-oak forest surface fires

Treesearch

R.L. Kremens; M.B. Dickinson; A.S. Bova

2012-01-01

Closing the wildland fire heat budget involves characterising the heat source and energy dissipation across the range of variability in fuels and fire behaviour. Meeting this challenge will lay the foundation for predicting direct ecological effects of fires and fire-atmosphere coupling. In this paper, we focus on the relationships between the fire radiation field, as...

The role of the global phase in the spatio-temporal evolution of strong-coupling Brillouin scattering

NASA Astrophysics Data System (ADS)

Amiranoff, F.; Riconda, C.; Chiaramello, M.; Lancia, L.; Marquès, J. R.; Weber, S.

2018-01-01

The role of the global phase in the spatio-temporal evolution of the 3-wave coupled equations for backscattering is analyzed in the strong-coupling regime of Brillouin scattering. This is of particular interest for controlled backscattering in the case of plasma-based amplification to produce short and intense laser pulses. It is shown that the analysis of the envelope equations of the three waves involved, pump, seed, and ion wave, in terms of phase and amplitude fully describes the coupling dynamics. In particular, it helps understanding the role of the chirp of the laser beams and of the plasma density profile. The results can be used to optimize or quench the coupling mechanism. It is found that the directionality of the energy transfer is imposed by the phase relation at the leading edge of the pulse. This actually ensures continued energy transfer even if the intensity of the seed pulse is already higher than the pump pulse intensity.

Interplay between the b →s l l anomalies and dark matter physics

NASA Astrophysics Data System (ADS)

Kawamura, Junichiro; Okawa, Shohei; Omura, Yuji

2017-10-01

Recently, the LHCb Collaboration has reported the excesses in the b →s l l processes. One of the promising candidates for new physics to explain the anomalies is the extended Standard Model (SM) with vectorlike quarks and leptons. In that model, Yukawa couplings between the extra fermions and SM fermions are introduced, adding extra scalars. Then, the box diagrams involving the extra fields achieve the b →s l l anomalies. It has been known that the excesses require the large Yukawa couplings of leptons, so that this kind of model can be tested by studying correlations with other observables. In this paper, we consider the extra scalar to be a dark matter (DM) candidate, and investigate DM physics as well as the flavor physics and the LHC physics. The DM relic density and the direct-detection cross section are also dominantly given by the Yukawa couplings, so that we find some explicit correlations between DM physics and the flavor physics. In particular, we find the predictions of the b →s l l anomalies against the direct detection of DM.

Coding "We-ness" in couple's relationship stories: A method for assessing mutuality in couple therapy.

PubMed

Gildersleeve, Sara; Singer, Jefferson A; Skerrett, Karen; Wein, Shelter

2017-05-01

"We-ness," a couple's mutual investment in their relationship and in each other, has been found to be a potent dimension of couple resilience. This study examined the development of a method to capture We-ness in psychotherapy through the coding of relationship narratives co-constructed by couples ("We-Stories"). It used a coding system to identify the core thematic elements that make up these narratives. Couples that self-identified as "happy" (N = 53) generated We-Stories and completed measures of relationship satisfaction and mutuality. These stories were then coded using the We-Stories coding manual. Findings indicated that security, an element that involves aspects of safety, support, and commitment, was most common, appearing in 58.5% of all narratives. This element was followed by the elements of pleasure (49.1%) and shared meaning/vision (37.7%). The number of "We-ness" elements was also correlated with and predictive of discrepancy scores on measures of relationship mutuality, indicating the validity of the We-Stories coding manual. Limitations and future directions are discussed.

The changing world of G protein-coupled receptors: from monomers to dimers and receptor mosaics with allosteric receptor-receptor interactions.

PubMed

Fuxe, Kjell; Marcellino, Daniel; Borroto-Escuela, Dasiel Oscar; Frankowska, Malgorzata; Ferraro, Luca; Guidolin, Diego; Ciruela, Francisco; Agnati, Luigi F

2010-10-01

Based on indications of direct physical interactions between neuropeptide and monoamine receptors in the early 1980s, the term receptor-receptor interactions was introduced and later on the term receptor heteromerization in the early 1990s. Allosteric mechanisms allow an integrative activity to emerge either intramolecularly in G protein-coupled receptor (GPCR) monomers or intermolecularly via receptor-receptor interactions in GPCR homodimers, heterodimers, and receptor mosaics. Stable heteromers of Class A receptors may be formed that involve strong high energy arginine-phosphate electrostatic interactions. These receptor-receptor interactions markedly increase the repertoire of GPCR recognition, signaling and trafficking in which the minimal signaling unit in the GPCR homomers appears to be one receptor and one G protein. GPCR homomers and GPCR assemblies are not isolated but also directly interact with other proteins to form horizontal molecular networks at the plasma membrane.

G protein-coupled odorant receptors: From sequence to structure.

PubMed

de March, Claire A; Kim, Soo-Kyung; Antonczak, Serge; Goddard, William A; Golebiowski, Jérôme

2015-09-01

Odorant receptors (ORs) are the largest subfamily within class A G protein-coupled receptors (GPCRs). No experimental structural data of any OR is available to date and atomic-level insights are likely to be obtained by means of molecular modeling. In this article, we critically align sequences of ORs with those GPCRs for which a structure is available. Here, an alignment consistent with available site-directed mutagenesis data on various ORs is proposed. Using this alignment, the choice of the template is deemed rather minor for identifying residues that constitute the wall of the binding cavity or those involved in G protein recognition. © 2015 The Protein Society.

RG flows for λ-deformed CFTs

NASA Astrophysics Data System (ADS)

Sagkrioti, E.; Sfetsos, K.; Siampos, K.

2018-05-01

We study the renormalization group equations of the fully anisotropic λ-deformed CFTs involving the direct product of two current algebras at different levels k1,2 for general semi-simple groups. The exact, in the deformation parameters, β-function is found via the effective action of the quantum fluctuations around a classical background as well as from gravitational techniques. Furthermore, agreement with known results for symmetric couplings and/or for equal levels, is demonstrated. We study in detail the two coupling case arising by splitting the group into a subgroup and the corresponding coset manifold which consistency requires to be either a symmetric-space one or a non-symmetric Einstein-space.

Collider study on the loop-induced dark matter mediation

NASA Astrophysics Data System (ADS)

Tsai, Yuhsin

2016-06-01

Collider experiments are one of the most promising ways to constrain Dark Matter (DM) interactions. For DM couplings involving light mediators, especially for the loop-mediated interactions, a meaningful interpretation of the results requires to go beyond effective field theory. In this note we discuss the study of the magnetic dipole interacting DM, focusing on a model with anarchic dark flavor structure. By including the momentum-dependent form factors that mediate the coupling - given by the Dark Penguin - in collider processes, we study bounds from monophoton, diphoton, and non-pointing photon searches at the LHC. We also compare our results to constraints from the direct detection experiments.

G protein-coupled odorant receptors: From sequence to structure

PubMed Central

de March, Claire A; Kim, Soo-Kyung; Antonczak, Serge; Goddard, William A; Golebiowski, Jérôme

2015-01-01

Odorant receptors (ORs) are the largest subfamily within class A G protein-coupled receptors (GPCRs). No experimental structural data of any OR is available to date and atomic-level insights are likely to be obtained by means of molecular modeling. In this article, we critically align sequences of ORs with those GPCRs for which a structure is available. Here, an alignment consistent with available site-directed mutagenesis data on various ORs is proposed. Using this alignment, the choice of the template is deemed rather minor for identifying residues that constitute the wall of the binding cavity or those involved in G protein recognition. PMID:26044705

A Conserved Asparagine Residue in Transmembrane Segment 1 (TM1) of Serotonin Transporter Dictates Chloride-coupled Neurotransmitter Transport*

PubMed Central

Henry, L. Keith; Iwamoto, Hideki; Field, Julie R.; Kaufmann, Kristian; Dawson, Eric S.; Jacobs, Miriam T.; Adams, Chelsea; Felts, Bruce; Zdravkovic, Igor; Armstrong, Vanessa; Combs, Steven; Solis, Ernesto; Rudnick, Gary; Noskov, Sergei Y.; DeFelice, Louis J.; Meiler, Jens; Blakely, Randy D.

2011-01-01

Na+- and Cl−-dependent uptake of neurotransmitters via transporters of the SLC6 family, including the human serotonin transporter (SLC6A4), is critical for efficient synaptic transmission. Although residues in the human serotonin transporter involved in direct Cl− coordination of human serotonin transport have been identified, the role of Cl− in the transport mechanism remains unclear. Through a combination of mutagenesis, chemical modification, substrate and charge flux measurements, and molecular modeling studies, we reveal an unexpected role for the highly conserved transmembrane segment 1 residue Asn-101 in coupling Cl− binding to concentrative neurotransmitter uptake. PMID:21730057

Time-Resolved Neutron Interferometry and the Mechanism of Electromechanical Coupling in Voltage-Gated Ion Channels.

PubMed

Blasie, J Kent

2018-01-01

The mechanism of electromechanical coupling for voltage-gated ion channels (VGICs) involved in neurological signal transmission, primarily Nav- and Kv-channels, remains unresolved. Anesthetics have been shown to directly impact this mechanism, at least for Kv-channels. Molecular dynamics computer simulations can now predict the structures of VGICs embedded within a hydrated phospholipid bilayer membrane as a function of the applied transmembrane voltage, but significant assumptions are still necessary. Nevertheless, these simulations are providing new insights into the mechanism of electromechanical coupling at the atomic level in 3-D. We show that time-resolved neutron interferometry can be used to investigate directly the profile structure of a VGIC, vectorially oriented within a single hydrated phospholipid bilayer membrane at the solid-liquid interface, as a function of the applied transmembrane voltage in the absence of any assumptions or potentially perturbing modifications of the VGIC protein and/or the host membrane. The profile structure is a projection of the membrane's 3-D structure onto the membrane normal and, in the absence of site-directed deuterium labeling, is provided at substantially lower spatial resolution than the atomic level. Nevertheless, this novel approach can be used to directly test the validity of the predictions from molecular dynamics simulations. We describe the key elements of our novel experimental approach, including why each is necessary and important to providing the essential information required for this critical comparison of "simulation" vs "experiment." In principle, the approach could be extended to higher spatial resolution and to include the effects of anesthetics on the electromechanical coupling mechanism in VGICs. © 2018 Elsevier Inc. All rights reserved.

Marital Quality and Conjugal Labor Involvement of Rural Couples.

ERIC Educational Resources Information Center

Bokemeier, Janet; Maurer, Richard

1987-01-01

Examined data from survey of nonmetropolitan households (N=770 couples) to describe conjugal labor involvement of rural couples and to assess relationship between labor involvement and marital quality. Found that, when work situations of both spouses were considered, many couples either had no jobs or more than two jobs. (Author/NB)

Function of Matrix IGF-1 in Coupling Bone Resorption and Formation

PubMed Central

Crane, Janet L.; Cao, Xu

2013-01-01

Balancing bone resorption and formation is the quintessential component for the prevention of osteoporosis. Signals that determine the recruitment, replication, differentiation, function, and apoptosis of osteoblasts and osteoclasts direct bone remodeling and determine whether bone tissue is gained, lost, or balanced. Therefore understanding the signaling pathways involved in the coupling process will help develop further targets for osteoporosis therapy, by blocking bone resorption or enhancing bone formation in a space and time dependent manner. Insulin-like growth factor type 1 (IGF-1) has long been known to play a role in bone strength. It is one of the most abundant substances in the bone matrix, circulates systemically and is secreted locally, and has a direct relationship with bone mineral density. Recent data has helped further our understanding of the direct role of IGF-1 signaling in coupling bone remodeling which will be discussed in this review. The bone marrow microenvironment plays a critical role in the fate of MSCs and HSCs and thus how IGF-1 interacts with other factors in the microenvironment are equally important. While previous clinical trials with IGF-1 administration have been unsuccessful at enhancing bone formation, advances in basic science studies have provided insight into further mechanisms that should be considered for future trials. Additional basic science studies dissecting the regulation and the function of matrix IGF-1 in modeling and remodeling will continue to provide further insight for future directions for anabolic therapies for osteoporosis. PMID:24068256

Function of matrix IGF-1 in coupling bone resorption and formation.

PubMed

Crane, Janet L; Cao, Xu

2014-02-01

Balancing bone resorption and formation is the quintessential component for the prevention of osteoporosis. Signals that determine the recruitment, replication, differentiation, function, and apoptosis of osteoblasts and osteoclasts direct bone remodeling and determine whether bone tissue is gained, lost, or balanced. Therefore, understanding the signaling pathways involved in the coupling process will help develop further targets for osteoporosis therapy, by blocking bone resorption or enhancing bone formation in a space- and time-dependent manner. Insulin-like growth factor type 1 (IGF-1) has long been known to play a role in bone strength. It is one of the most abundant substances in the bone matrix, circulates systemically and is secreted locally, and has a direct relationship with bone mineral density. Recent data has helped further our understanding of the direct role of IGF-1 signaling in coupling bone remodeling which will be discussed in this review. The bone marrow microenvironment plays a critical role in the fate of mesenchymal stem cells and hematopoietic stem cells and thus how IGF-1 interacts with other factors in the microenvironment are equally important. While previous clinical trials with IGF-1 administration have been unsuccessful at enhancing bone formation, advances in basic science studies have provided insight into further mechanisms that should be considered for future trials. Additional basic science studies dissecting the regulation and the function of matrix IGF-1 in modeling and remodeling will continue to provide further insight for future directions for anabolic therapies for osteoporosis.

The direct field boundary impedance of two-dimensional periodic structures with application to high frequency vibration prediction.

PubMed

Langley, Robin S; Cotoni, Vincent

2010-04-01

Large sections of many types of engineering construction can be considered to constitute a two-dimensional periodic structure, with examples ranging from an orthogonally stiffened shell to a honeycomb sandwich panel. In this paper, a method is presented for computing the boundary (or edge) impedance of a semi-infinite two-dimensional periodic structure, a quantity which is referred to as the direct field boundary impedance matrix. This terminology arises from the fact that none of the waves generated at the boundary (the direct field) are reflected back to the boundary in a semi-infinite system. The direct field impedance matrix can be used to calculate elastic wave transmission coefficients, and also to calculate the coupling loss factors (CLFs), which are required by the statistical energy analysis (SEA) approach to predicting high frequency vibration levels in built-up systems. The calculation of the relevant CLFs enables a two-dimensional periodic region of a structure to be modeled very efficiently as a single subsystem within SEA, and also within related methods, such as a recently developed hybrid approach, which couples the finite element method with SEA. The analysis is illustrated by various numerical examples involving stiffened plate structures.

Cross-dehydrogenative coupling for the intermolecular C–O bond formation

PubMed Central

Krylov, Igor B; Vil’, Vera A

2015-01-01

Summary The present review summarizes primary publications on the cross-dehydrogenative C–O coupling, with special emphasis on the studies published after 2000. The starting compound, which donates a carbon atom for the formation of a new C–O bond, is called the CH-reagent or the C-reagent, and the compound, an oxygen atom of which is involved in the new bond, is called the OH-reagent or the O-reagent. Alcohols and carboxylic acids are most commonly used as O-reagents; hydroxylamine derivatives, hydroperoxides, and sulfonic acids are employed less often. The cross-dehydrogenative C–O coupling reactions are carried out using different C-reagents, such as compounds containing directing functional groups (amide, heteroaromatic, oxime, and so on) and compounds with activated C–H bonds (aldehydes, alcohols, ketones, ethers, amines, amides, compounds containing the benzyl, allyl, or propargyl moiety). An analysis of the published data showed that the principles at the basis of a particular cross-dehydrogenative C–O coupling reaction are dictated mainly by the nature of the C-reagent. Hence, in the present review the data are classified according to the structures of C-reagents, and, in the second place, according to the type of oxidative systems. Besides the typical cross-dehydrogenative coupling reactions of CH- and OH-reagents, closely related C–H activation processes involving intermolecular C–O bond formation are discussed: acyloxylation reactions with ArI(O2CR)2 reagents and generation of O-reagents in situ from C-reagents (methylarenes, aldehydes, etc.). PMID:25670997

AGN outflows and feedback twenty years on

NASA Astrophysics Data System (ADS)

Harrison, C. M.; Costa, T.; Tadhunter, C. N.; Flütsch, A.; Kakkad, D.; Perna, M.; Vietri, G.

2018-03-01

It is twenty years since the seminal works by Magorrian and co-authors and by Silk and Rees, which, along with other related work, ignited an explosion of publications connecting active galactic nucleus (AGN)-driven outflows to galaxy evolution. With a surge in observations of AGN outflows, studies are attempting to test AGN feedback models directly using the outflow properties. With a focus on outflows traced by optical and CO emission lines, we discuss significant challenges that greatly complicate this task, from both an observational and theoretical perspective. We highlight the observational uncertainties involved and the assumptions required when deriving kinetic coupling efficiencies (that is, outflow kinetic power as a fraction of AGN luminosity) from typical observations. Based on recent models we demonstrate that extreme caution should be taken when comparing observationally derived kinetic coupling efficiencies to coupling efficiencies from fiducial feedback models.

Coupled skinny baker's maps and the Kaplan-Yorke conjecture

NASA Astrophysics Data System (ADS)

Gröger, Maik; Hunt, Brian R.

2013-09-01

The Kaplan-Yorke conjecture states that for ‘typical’ dynamical systems with a physical measure, the information dimension and the Lyapunov dimension coincide. We explore this conjecture in a neighborhood of a system for which the two dimensions do not coincide because the system consists of two uncoupled subsystems. We are interested in whether coupling ‘typically’ restores the equality of the dimensions. The particular subsystems we consider are skinny baker's maps, and we consider uni-directional coupling. For coupling in one of the possible directions, we prove that the dimensions coincide for a prevalent set of coupling functions, but for coupling in the other direction we show that the dimensions remain unequal for all coupling functions. We conjecture that the dimensions prevalently coincide for bi-directional coupling. On the other hand, we conjecture that the phenomenon we observe for a particular class of systems with uni-directional coupling, where the information and Lyapunov dimensions differ robustly, occurs more generally for many classes of uni-directionally coupled systems (also called skew-product systems) in higher dimensions.

Carrier-envelope phase dependence of the directional fragmentation and hydrogen migration in toluene in few-cycle laser fields.

PubMed

Li, Hui; Kling, Nora G; Förg, Benjamin; Stierle, Johannes; Kessel, Alexander; Trushin, Sergei A; Kling, Matthias F; Kaziannis, Spyros

2016-07-01

The dissociative ionization of toluene initiated by a few-cycle laser pulse as a function of the carrier envelope phase (CEP) is investigated using single-shot velocity map imaging. Several ionic fragments, CH3 (+), H2 (+), and H3 (+), originating from multiply charged toluene ions present a CEP-dependent directional emission. The formation of H2 (+) and H3 (+) involves breaking C-H bonds and forming new bonds between the hydrogen atoms within the transient structure of the multiply charged precursor. We observe appreciable intensity-dependent CEP-offsets. The experimental data are interpreted with a mechanism that involves laser-induced coupling of vibrational states, which has been found to play a role in the CEP-control of molecular processes in hydrocarbon molecules, and appears to be of general importance for such complex molecules.

Distributed coupling high efficiency linear accelerator

DOEpatents

Tantawi, Sami G.; Neilson, Jeffrey

2016-07-19

A microwave circuit for a linear accelerator includes multiple monolithic metallic cell plates stacked upon each other so that the beam axis passes vertically through a central acceleration cavity of each plate. Each plate has a directional coupler with coupling arms. A first coupling slot couples the directional coupler to an adjacent directional coupler of an adjacent cell plate, and a second coupling slot couples the directional coupler to the central acceleration cavity. Each directional coupler also has an iris protrusion spaced from corners joining the arms, a convex rounded corner at a first corner joining the arms, and a corner protrusion at a second corner joining the arms.

Adenosine receptor desensitization and trafficking.

PubMed

Mundell, Stuart; Kelly, Eamonn

2011-05-01

As with the majority of G-protein-coupled receptors, all four of the adenosine receptor subtypes are known to undergo agonist-induced regulation in the form of desensitization and trafficking. These processes can limit the ability of adenosine receptors to couple to intracellular signalling pathways and thus reduce the ability of adenosine receptor agonists as well as endogenous adenosine to produce cellular responses. In addition, since adenosine receptors couple to multiple signalling pathways, these pathways may desensitize differentially, while the desensitization of one pathway could even trigger signalling via another. Thus, the overall picture of adenosine receptor regulation can be complex. For all adenosine receptor subtypes, there is evidence to implicate arrestins in agonist-induced desensitization and trafficking, but there is also evidence for other possible forms of regulation, including second messenger-dependent kinase regulation, heterologous effects involving G proteins, and the involvement of non-clathrin trafficking pathways such as caveolae. In this review, the evidence implicating these mechanisms is summarized for each adenosine receptor subtype, and we also discuss those issues of adenosine receptor regulation that remain to be resolved as well as likely directions for future research in this field. Copyright © 2010 Elsevier B.V. All rights reserved.

An Overview of A Perturbation Analysis for Uni-directionally Coupled Vibratory Gyroscopes

NASA Astrophysics Data System (ADS)

Vu, Huy; Palacios, Antonio; In, Visarath; Longhini, Patrick; Neff, Joseph

2011-04-01

The complex behaviours of gyroscope systems have been scientifically researched and thoroughly studied for decades. Most of scientific research involving gyroscopes specifically concentrates on studying the designs and fabrications at the circuitry level. Although gaining a recent popularity with the low cost of MEMS device that offers an attractive approach for gyroscope fabrications, its performance is far from meeting the requirements for an inertial grade guidance system. To improve the performance, our current research is theoretically focusing upon investigating the dynamics of vibratory gyroscopes coupled in a ring configuration. Particularly, a certain topology of arrangements among coupled gyroscopes can be designed and studied to enhance robustness. The main operation depends mostly on an external source for a stable oscillation in the drive axis, while an oscillatory motion in the sense axis, which is used to detect an angular rate of rotation, is enabled through the transfers of energy from the drive via the Coriolis force. With the mathematical model depicted as Duffing oscillators, however, by adding a certain coupling among gyroscopes, a similar behavior to a Duffing oscillator is expected, only with more complicated dynamics at a higher dimension. A number of Perturbation methods have popularly been carried out, to seek for a general asymptotic solution of typical Duffing oscillators. In this work as an overview, the two-time scale Perturbation expansion is asymptotically applied on the uni-directionally coupled vibratory gyroscopes to find an analytical solution which is then compared to the numerical one.

Fan Noise Prediction System Development: Source/Radiation Field Coupling and Workstation Conversion for the Acoustic Radiation Code

NASA Technical Reports Server (NTRS)

Meyer, H. D.

1993-01-01

The Acoustic Radiation Code (ARC) is a finite element program used on the IBM mainframe to predict far-field acoustic radiation from a turbofan engine inlet. In this report, requirements for developers of internal aerodynamic codes regarding use of their program output an input for the ARC are discussed. More specifically, the particular input needed from the Bolt, Beranek and Newman/Pratt and Whitney (turbofan source noise generation) Code (BBN/PWC) is described. In a separate analysis, a method of coupling the source and radiation models, that recognizes waves crossing the interface in both directions, has been derived. A preliminary version of the coupled code has been developed and used for initial evaluation of coupling issues. Results thus far have shown that reflection from the inlet is sufficient to indicate that full coupling of the source and radiation fields is needed for accurate noise predictions ' Also, for this contract, the ARC has been modified for use on the Sun and Silicon Graphics Iris UNIX workstations. Changes and additions involved in this effort are described in an appendix.

Scattering of fermions in the Yukawa theory coupled to unimodular gravity

NASA Astrophysics Data System (ADS)

Gonzalez-Martin, S.; Martin, C. P.

2018-03-01

We compute the lowest order gravitational UV divergent radiative corrections to the S matrix element of the fermion + fermion→ fermion + fermion scattering process in the massive Yukawa theory, coupled either to Unimodular Gravity or to General Relativity. We show that both Unimodular Gravity and General Relativity give rise to the same UV divergent contribution in Dimensional Regularization. This is a nontrivial result, since in the classical action of Unimodular Gravity coupled to the Yukawa theory, the graviton field does not couple neither to the mass operator nor to the Yukawa operator. This is unlike the General Relativity case. The agreement found points in the direction that Unimodular Gravity and General Relativity give rise to the same quantum theory when coupled to matter, as long as the Cosmological Constant vanishes. Along the way we have come across another unexpected cancellation of UV divergences for both Unimodular Gravity and General Relativity, resulting in the UV finiteness of the one-loop and κ y^2 order of the vertex involving two fermions and one graviton only.

Transition-edge superconducting antenna-coupled bolometer

NASA Astrophysics Data System (ADS)

Hunt, Cynthia L.; Bock, James J.; Day, Peter K.; Goldin, Alexey; Lange, Andrew E.; LeDuc, Henry G.; Vayonakis, Anastasios; Zmuidzinas, Jonas

2003-02-01

We report test results for a single pixel antenna-coupled bolometric detector. Our device consists of a dual slot microstrip antenna coupled to an Al/Ti/Au voltage-biased transition edge superconducting bolometer (TES). The coupling architecture involves propagating the signal along superconducting microstrip lines and terminating the lines at a normal metal resistor colocated with a TES on a thermally isolated island. The device, which is inherently polarization sensitive, is optimized for 140 GHz band measurements. In the thermal bandwidth of the TES, we measure a noise equivalent power of 2.0 × 10-17 W/√Hz in dark tests that agrees with calculated NEP including only contributions from thermal, Johnson and amplifier noise. We do not measure any excess noise at frequencies between 1 and 200 Hz. We measure a thermal conductance G ~5.5 × 10-11 W/K. We measure a thermal time constant as low as 437μs at 3μV bias when stimulating the TES directly using an LED.

Stabilization of domain walls between traveling waves by nonlinear mode coupling in Taylor-Couette flow.

PubMed

Heise, M; Hoffmann, Ch; Abshagen, J; Pinter, A; Pfister, G; Lücke, M

2008-02-15

We present a new mechanism that allows the stable existence of domain walls between oppositely traveling waves in pattern-forming systems far from onset. It involves a nonlinear mode coupling that results directly from the nonlinearities in the underlying momentum balance. Our work provides the first observation and explanation of such strongly nonlinearly driven domain walls that separate structured states by a phase generating or annihilating defect. Furthermore, the influence of a symmetry breaking externally imposed flow on the wave domains and the domain walls is studied. The results are obtained for vortex waves in the Taylor-Couette system by combining numerical simulations of the full Navier-Stokes equations and experimental measurements.

A new detection scheme for ultrafast 2D J-resolved spectroscopy

NASA Astrophysics Data System (ADS)

Giraudeau, Patrick; Akoka, Serge

2007-06-01

Recent ultrafast techniques enable 2D NMR spectra to be obtained in a single scan. A modification of the detection scheme involved in this technique is proposed, permitting the achievement of 2D 1H J-resolved spectra in 500 ms. The detection gradient echoes are substituted by spin echoes to obtain spectra where the coupling constants are encoded along the direct ν2 domain. The use of this new J-resolved detection block after continuous phase-encoding excitation schemes is discussed in terms of resolution and sensitivity. J-resolved spectra obtained on cinnamic acid and 3-ethyl bromopropionate are presented, revealing the expected 2D J-patterns with coupling constants as small as 2 Hz.

Collider study on the loop-induced dark matter mediation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tsai, Yuhsin, E-mail: yhtsai@umd.edu

2016-06-21

Collider experiments are one of the most promising ways to constrain Dark Matter (DM) interactions. For DM couplings involving light mediators, especially for the loop-mediated interactions, a meaningful interpretation of the results requires to go beyond effective field theory. In this note we discuss the study of the magnetic dipole interacting DM, focusing on a model with anarchic dark flavor structure. By including the momentum-dependent form factors that mediate the coupling – given by the Dark Penguin – in collider processes, we study bounds from monophoton, diphoton, and non-pointing photon searches at the LHC. We also compare our results tomore » constraints from the direct detection experiments.« less

Monitoring nonadiabatic avoided crossing dynamics in molecules by ultrafast X-ray diffraction

DOE PAGES

Kowalewski, Markus; Bennett, Kochise; Mukamel, Shaul

2017-05-26

We examine time-resolved X-ray diffraction from molecules in the gas phase which undergo nonadiabatic avoided-crossing dynamics involving strongly coupled electrons and nuclei. Several contributions to the signal are identified, representing (in decreasing strength) elastic scattering, contributions of the electronic coherences created by nonadiabatic couplings in the avoided crossing regime, and inelastic scattering. The former probes the charge density and delivers direct information on the evolving molecular geometry. The latter two contributions are weaker and carry spatial information through the transition charge densities (off-diagonal elements of the charge-density operator). Furthermore, simulations are presented for the nonadiabatic harpooning process in the excitedmore » state of sodium fluoride.« less

Systematic expansion in the order parameter for replica theory of the dynamical glass transition.

PubMed

Jacquin, Hugo; Zamponi, Francesco

2013-03-28

It has been shown recently that predictions from mode-coupling theory for the glass transition of hard-spheres become increasingly bad when dimensionality increases, whereas replica theory predicts a correct scaling. Nevertheless if one focuses on the regime around the dynamical transition in three dimensions, mode-coupling results are far more convincing than replica theory predictions. It seems thus necessary to reconcile the two theoretic approaches in order to obtain a theory that interpolates between low-dimensional, mode-coupling results, and "mean-field" results from replica theory. Even though quantitative results for the dynamical transition issued from replica theory are not accurate in low dimensions, two different approximation schemes--small cage expansion and replicated hyper-netted-chain (RHNC)--provide the correct qualitative picture for the transition, namely, a discontinuous jump of a static order parameter from zero to a finite value. The purpose of this work is to develop a systematic expansion around the RHNC result in powers of the static order parameter, and to calculate the first correction in this expansion. Interestingly, this correction involves the static three-body correlations of the liquid. More importantly, we separately demonstrate that higher order terms in the expansion are quantitatively relevant at the transition, and that the usual mode-coupling kernel, involving two-body direct correlation functions of the liquid, cannot be recovered from static computations.

Direct heuristic dynamic programming for damping oscillations in a large power system.

PubMed

Lu, Chao; Si, Jennie; Xie, Xiaorong

2008-08-01

This paper applies a neural-network-based approximate dynamic programming method, namely, the direct heuristic dynamic programming (direct HDP), to a large power system stability control problem. The direct HDP is a learning- and approximation-based approach to addressing nonlinear coordinated control under uncertainty. One of the major design parameters, the controller learning objective function, is formulated to directly account for network-wide low-frequency oscillation with the presence of nonlinearity, uncertainty, and coupling effect among system components. Results include a novel learning control structure based on the direct HDP with applications to two power system problems. The first case involves static var compensator supplementary damping control, which is used to provide a comprehensive evaluation of the learning control performance. The second case aims at addressing a difficult complex system challenge by providing a new solution to a large interconnected power network oscillation damping control problem that frequently occurs in the China Southern Power Grid.

Direct evidence that an extended hydrogen-bonding network influences activation of pyridoxal 5'-phosphate in aspartate aminotransferase

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dajnowicz, Steven; Parks, Jerry M.; Hu, Xiche

We used pyridoxal 5'-phosphate (PLP) is a fundamental, multifunctional enzyme cofactor to catalyze a wide variety of chemical reactions involved in amino acid metabolism. PLP-dependent enzymes optimize specific chemical reactions by modulating the electronic states of PLP through distinct active site environments. In aspartate aminotransferase (AAT), an extended hydrogen bond network is coupled to the pyridinyl nitrogen of the PLP, influencing the electrophilicity of the cofactor. This network, which involves residues Asp-222, His-143, Thr-139, His-189, and structural waters, is located at the edge of PLP opposite the reactive Schiff base. We demonstrate that this hydrogen bond network directly influences themore » protonation state of the pyridine nitrogen of PLP, which affects the rates of catalysis. We analyzed perturbations caused by single- and double-mutant variants using steady-state kinetics, high resolution X-ray crystallography, and quantum chemical calculations. Protonation of the pyridinyl nitrogen to form a pyridinium cation induces electronic delocalization in the PLP, which correlates with the enhancement in catalytic rate in AAT. Therefore, PLP activation is controlled by the proximity of the pyridinyl nitrogen to the hydrogen bond microenvironment. Quantum chemical calculations indicate that Asp-222, which is directly coupled to the pyridinyl nitrogen, increases the pKa of the pyridine nitrogen and stabilizes the pyridinium cation. His-143 and His-189 also increase the pKa of the pyridine nitrogen but, more significantly, influence the position of the proton that resides between Asp-222 and the pyridinyl nitrogen. Our findings indicate that the second shell residues directly enhance the rate of catalysis in AAT.« less

Direct evidence that an extended hydrogen-bonding network influences activation of pyridoxal 5'-phosphate in aspartate aminotransferase

DOE PAGES

Dajnowicz, Steven; Parks, Jerry M.; Hu, Xiche; ...

2017-02-23

We used pyridoxal 5'-phosphate (PLP) is a fundamental, multifunctional enzyme cofactor to catalyze a wide variety of chemical reactions involved in amino acid metabolism. PLP-dependent enzymes optimize specific chemical reactions by modulating the electronic states of PLP through distinct active site environments. In aspartate aminotransferase (AAT), an extended hydrogen bond network is coupled to the pyridinyl nitrogen of the PLP, influencing the electrophilicity of the cofactor. This network, which involves residues Asp-222, His-143, Thr-139, His-189, and structural waters, is located at the edge of PLP opposite the reactive Schiff base. We demonstrate that this hydrogen bond network directly influences themore » protonation state of the pyridine nitrogen of PLP, which affects the rates of catalysis. We analyzed perturbations caused by single- and double-mutant variants using steady-state kinetics, high resolution X-ray crystallography, and quantum chemical calculations. Protonation of the pyridinyl nitrogen to form a pyridinium cation induces electronic delocalization in the PLP, which correlates with the enhancement in catalytic rate in AAT. Therefore, PLP activation is controlled by the proximity of the pyridinyl nitrogen to the hydrogen bond microenvironment. Quantum chemical calculations indicate that Asp-222, which is directly coupled to the pyridinyl nitrogen, increases the pKa of the pyridine nitrogen and stabilizes the pyridinium cation. His-143 and His-189 also increase the pKa of the pyridine nitrogen but, more significantly, influence the position of the proton that resides between Asp-222 and the pyridinyl nitrogen. Our findings indicate that the second shell residues directly enhance the rate of catalysis in AAT.« less

Resting-state EEG coupling analysis of amnestic mild cognitive impairment with type 2 diabetes mellitus by using permutation conditional mutual information.

PubMed

Wen, Dong; Bian, Zhijie; Li, Qiuli; Wang, Lei; Lu, Chengbiao; Li, Xiaoli

2016-01-01

This study was meant to explore whether the coupling strength and direction of resting-state electroencephalogram (rsEEG) could be used as an indicator to distinguish the patients of type 2 diabetes mellitus (T2DM) with or without amnestic mild cognitive impairment (aMCI). Permutation conditional mutual information (PCMI) was used to calculate the coupling strength and direction of rsEEG signals between different brain areas of 19 aMCI and 20 normal control (NC) with T2DM on 7 frequency bands: Delta, Theta, Alpha1, Alpha2, Beta1, Beta2 and Gamma. The difference in coupling strength or direction of rsEEG between two groups was calculated. The correlation between coupling strength or direction of rsEEG and score of different neuropsychology scales were also calculated. We have demonstrated that PCMI can calculate effectively the coupling strength and directionality of EEG signals between different brain regions. The significant difference in coupling strength and directionality of EEG signals was found between the patients of aMCI and NC with T2DM on different brain regions. There also existed significant correlation between sex or age and coupling strength or coupling directionality of EEG signals between a few different brain regions from all subjects. The coupling strength or directionality of EEG signals calculated by PCMI are significantly different between aMCI and NC with T2DM. These results showed that the coupling strength or directionality of EEG signals calculated by PCMI might be used as a biomarker in distinguishing the aMCI from NC with T2DM. Copyright © 2015 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

A multi-state fragment charge difference approach for diabatic states in electron transfer: Extension and automation

NASA Astrophysics Data System (ADS)

Yang, Chou-Hsun; Hsu, Chao-Ping

2013-10-01

The electron transfer (ET) rate prediction requires the electronic coupling values. The Generalized Mulliken-Hush (GMH) and Fragment Charge Difference (FCD) schemes have been useful approaches to calculate ET coupling from an excited state calculation. In their typical form, both methods use two eigenstates in forming the target charge-localized diabatic states. For problems involve three or four states, a direct generalization is possible, but it is necessary to pick and assign the locally excited or charge-transfer states involved. In this work, we generalize the 3-state scheme for a multi-state FCD without the need of manual pick or assignment for the states. In this scheme, the diabatic states are obtained separately in the charge-transfer or neutral excited subspaces, defined by their eigenvalues in the fragment charge-difference matrix. In each subspace, the Hamiltonians are diagonalized, and there exist off-diagonal Hamiltonian matrix elements between different subspaces, particularly the charge-transfer and neutral excited diabatic states. The ET coupling values are obtained as the corresponding off-diagonal Hamiltonian matrix elements. A similar multi-state GMH scheme can also be developed. We test the new multi-state schemes for the performance in systems that have been studied using more than two states with FCD or GMH. We found that the multi-state approach yields much better charge-localized states in these systems. We further test for the dependence on the number of state included in the calculation of ET couplings. The final coupling values are converged when the number of state included is increased. In one system where experimental value is available, the multi-state FCD coupling value agrees better with the previous experimental result. We found that the multi-state GMH and FCD are useful when the original two-state approach fails.

Regulation of CaV2 calcium channels by G protein coupled receptors

PubMed Central

Zamponi, Gerald W.; Currie, Kevin P.M.

2012-01-01

Voltage gated calcium channels (Ca2+ channels) are key mediators of depolarization induced calcium influx into excitable cells, and thereby play pivotal roles in a wide array of physiological responses. This review focuses on the inhibition of CaV2 (N- and P/Q-type) Ca2+-channels by G protein coupled receptors (GPCRs), which exerts important autocrine/paracrine control over synaptic transmission and neuroendocrine secretion. Voltage-dependent inhibition is the most widespread mechanism, and involves direct binding of the G protein βγ dimer (Gβγ) to the α1 subunit of CaV2 channels. GPCRs can also recruit several other distinct mechanisms including phosphorylation, lipid signaling pathways, and channel trafficking that result in voltage-independent inhibition. Current knowledge of Gβγ-mediated inhibition is reviewed, including the molecular interactions involved, determinants of voltage-dependence, and crosstalk with other cell signaling pathways. A summary of recent developments in understanding the voltage-independent mechanisms prominent in sympathetic and sensory neurons is also included. PMID:23063655

Small slot waveguide rings for on-chip quantum optical circuits.

PubMed

Rotenberg, Nir; Türschmann, Pierre; Haakh, Harald R; Martin-Cano, Diego; Götzinger, Stephan; Sandoghdar, Vahid

2017-03-06

Nanophotonic interfaces between single emitters and light promise to enable new quantum optical technologies. Here, we use a combination of finite element simulations and analytic quantum theory to investigate the interaction of various quantum emitters with slot-waveguide rings. We predict that for rings with radii as small as 1.44 μm, with a Q-factor of 27,900, near-unity emitter-waveguide coupling efficiencies and emission enhancements on the order of 1300 can be achieved. By tuning the ring geometry or introducing losses, we show that realistic emitter-ring systems can be made to be either weakly or strongly coupled, so that we can observe Rabi oscillations in the decay dynamics even for micron-sized rings. Moreover, we demonstrate that slot waveguide rings can be used to directionally couple emission, again with near-unity efficiency. Our results pave the way for integrated solid-state quantum circuits involving various emitters.

A Simplified Theory of Coupled Oscillator Array Phase Control

NASA Technical Reports Server (NTRS)

Pogorzelski, R. J.; York, R. A.

1997-01-01

Linear and planar arrays of coupled oscillators have been proposed as means of achieving high power rf sources through coherent spatial power combining. In such - applications, a uniform phase distribution over the aperture is desired. However, it has been shown that by detuning some of the oscillators away from the oscillation frequency of the ensemble of oscillators, one may achieve other useful aperture phase distributions. Notable among these are linear phase distributions resulting in steering of the output rf beam away from the broadside direction. The theory describing the operation of such arrays of coupled oscillators is quite complicated since the phenomena involved are inherently nonlinear. This has made it difficult to develop an intuitive understanding of the impact of oscillator tuning on phase control and has thus impeded practical application. In this work a simpl!fied theory is developed which facilitates intuitive understanding by establishing an analog of the phase control problem in terms of electrostatics.

Absence of a direct role of phospholipid methylation in stimulus-secretion coupling and control of adenylate cyclase in guinea-pig and rat parotid gland.

PubMed Central

Padel, U; Unger, C; Söling, H D

1982-01-01

The present study was undertaken to investigate a possible involvement of phospholipid methyltransferases in the coupling of receptor-mediated stimulation to secretion. Phospholipid methyltransferases were assayed in isolated parotid acini in the presence of carbamoylcholine or isoprenaline. Carbamoylcholine reduced the incorporation of methyl groups into phospholipids, whereas isoprenaline showed no effect. Amylase secretion stimulated either by carbamoylcholine or by isoprenaline could not be affected by inhibitors of methyltransferases (3-deaza-adenosine alone or plus homocysteine thiolactone) under conditions where phospholipid methylation was strongly inhibited. The activity of adenylate cyclase in isolated parotid microsomal membranes was not inhibited or stimulated by S-adenosyl-homocysteine or -methionine respectively. These results indicate that phospholipid methylation does not play an essential role in stimulus-secretion coupling in the parotid gland. PMID:6186246

Distinguishing between direct and indirect directional couplings in large oscillator networks: Partial or non-partial phase analyses?

NASA Astrophysics Data System (ADS)

Rings, Thorsten; Lehnertz, Klaus

2016-09-01

We investigate the relative merit of phase-based methods for inferring directional couplings in complex networks of weakly interacting dynamical systems from multivariate time-series data. We compare the evolution map approach and its partialized extension to each other with respect to their ability to correctly infer the network topology in the presence of indirect directional couplings for various simulated experimental situations using coupled model systems. In addition, we investigate whether the partialized approach allows for additional or complementary indications of directional interactions in evolving epileptic brain networks using intracranial electroencephalographic recordings from an epilepsy patient. For such networks, both direct and indirect directional couplings can be expected, given the brain's connection structure and effects that may arise from limitations inherent to the recording technique. Our findings indicate that particularly in larger networks (number of nodes ≫10 ), the partialized approach does not provide information about directional couplings extending the information gained with the evolution map approach.

Coordination of locomotor and cardiorespiratory networks of Lymnaea stagnalis by a pair of identified interneurones.

PubMed

Syed, N I; Winlow, W

1991-07-01

1. The morphology and electrophysiology of a newly identified bilateral pair of interneurones in the central nervous system of the pulmonate pond snail Lymnaea stagnalis is described. 2. These interneurones, identified as left and right pedal dorsal 11 (L/RPeD11), are electrically coupled to each other as well as to a large number of foot and body wall motoneurones, forming a fast-acting neural network which coordinates the activities of foot and body wall muscles. 3. The left and right sides of the body wall of Lymnaea are innervated by left and right cerebral A cluster neurones. Although these motoneurones have only ipsilateral projections, they are indirectly electrically coupled to their contralateral homologues via their connections with L/RPeD11. Similarly, the activities of left and right pedal G cluster neurones, which are known to be involved in locomotion, are also coordinated by L/RPeD11. 4. Selective ablation of both neurones PeD11 results in the loss of coordination between the bilateral cerebral A clusters. 5. Interneurones L/RPeD11 are multifunctional. In addition to coordinating motoneuronal activity, they make chemical excitatory connections with heart motoneurones. They also synapse upon respiratory motoneurones, hyperpolarizing those involved in pneumostome opening (expiration) and depolarizing those involved in pneumostome closure (inspiration). 6. An identified respiratory interneurone involved in pneumostome closure (visceral dorsal 4) inhibits L/RPeD11 together with all their electrically coupled follower cells. 7. Both L/RPeD11 have strong excitatory effects on another pair of electrically coupled neurones, visceral dorsal 1 and right parietal dorsal 2, which have previously been shown to be sensitive to changes in the partial pressure of environmental oxygen (PO2). 8. Although L/RPeD11 participate in whole-body withdrawal responses, electrical stimulation applied directly to these neurones was not sufficient to induce this behaviour.

Simulation of electron-proton coupling with a Monte Carlo method: application to cytochrome c3 using continuum electrostatics.

PubMed Central

Baptista, A M; Martel, P J; Soares, C M

1999-01-01

A new method is presented for simulating the simultaneous binding equilibrium of electrons and protons on protein molecules, which makes it possible to study the full equilibrium thermodynamics of redox and protonation processes, including electron-proton coupling. The simulations using this method reflect directly the pH and electrostatic potential of the environment, thus providing a much closer and realistic connection with experimental parameters than do usual methods. By ignoring the full binding equilibrium, calculations usually overlook the twofold effect that binding fluctuations have on the behavior of redox proteins: first, they affect the energy of the system by creating partially occupied sites; second, they affect its entropy by introducing an additional empty/occupied site disorder (here named occupational entropy). The proposed method is applied to cytochrome c3 of Desulfovibrio vulgaris Hildenborough to study its redox properties and electron-proton coupling (redox-Bohr effect), using a continuum electrostatic method based on the linear Poisson-Boltzmann equation. Unlike previous studies using other methods, the full reduction order of the four hemes at physiological pH is successfully predicted. The sites more strongly involved in the redox-Bohr effect are identified by analysis of their titration curves/surfaces and the shifts of their midpoint redox potentials and pKa values. Site-site couplings are analyzed using statistical correlations, a method much more realistic than the usual analysis based on direct interactions. The site found to be more strongly involved in the redox-Bohr effect is propionate D of heme I, in agreement with previous studies; other likely candidates are His67, the N-terminus, and propionate D of heme IV. Even though the present study is limited to equilibrium conditions, the possible role of binding fluctuations in the concerted transfer of protons and electrons under nonequilibrium conditions is also discussed. The occupational entropy contributions to midpoint redox potentials and pKa values are computed and shown to be significant. PMID:10354425

Changes in corticocortical and corticohippocampal network during absence seizures in WAG/Rij rats revealed with time varying Granger causality.

PubMed

Sysoeva, Marina V; Vinogradova, Lyudmila V; Kuznetsova, Galina D; Sysoev, Ilya V; van Rijn, Clementina M

2016-11-01

Spike-and-wave discharges (SWDs) recorded in the cortical EEGs of WAG/Rij rats are the hallmark for absence epilepsy in this model. Although this type of epilepsy was long regarded as a form of primary generalized epilepsy, it is now recognized that there is an initiation zone - the perioral region of the somatosensory cortex. However, networks involved in spreading the seizure are not yet fully known. Previously, the dynamics of coupling between different layers of the perioral cortical region and between these zones and different thalamic nuclei was studied in time windows around the SWDs, using nonlinear Granger causality. The aim of the present study was to investigate, using the same method, the coupling dynamics between different regions of the cortex and between these regions and the hippocampus. Local field potentials were recorded in the frontal, parietal, and occipital cortices and in the hippocampus of 19 WAG/Rij rats. To detect changes in coupling reliably in a short time window, in order to provide a good temporal resolution, the innovative adapted time varying nonlinear Granger causality method was used. Mutual information function was calculated in addition to validate outcomes. Results of both approaches were tested for significance. The SWD initiation process was revealed as an increase in intracortical interactions starting from 3.5s before the onset of electrographic seizure. The earliest preictal increase in coupling was directed from the frontal cortex to the parietal cortex. Then, the coupling became bidirectional, followed by the involvement of the occipital cortex (1.5s before SWD onset). There was no driving from any cortical region to hippocampus, but a slight increase in coupling from hippocampus to the frontoparietal cortex was observed just before SWD onset. After SWD onset, an abrupt drop in coupling in all studied pairs was observed. In most of the pairs, the decoupling rapidly disappeared, but driving force from hippocampus and occipital cortex to the frontoparietal cortex was reduced until the SWD termination. Involvement of multiple cortical regions in SWD initiation shows the fundamental role of corticocortical feedback loops, forming coupling architecture and triggering the generalized seizure. The results add to the ultimate aim to construct a complete picture of brain interactions preceding and accompanying absence seizures in rats. Copyright © 2016 Elsevier Inc. All rights reserved.

Dynamic analysis for shuttle design verification

NASA Technical Reports Server (NTRS)

Fralich, R. W.; Green, C. E.; Rheinfurth, M. H.

1972-01-01

Two approaches that are used for determining the modes and frequencies of space shuttle structures are discussed. The first method, direct numerical analysis, involves finite element mathematical modeling of the space shuttle structure in order to use computer programs for dynamic structural analysis. The second method utilizes modal-coupling techniques of experimental verification made by vibrating only spacecraft components and by deducing modes and frequencies of the complete vehicle from results obtained in the component tests.

Putting out the fire: what terminates calcium-induced calcium release in cardiac muscle?

PubMed

Stern, Michael D; Cheng, Heping

2004-06-01

The majority of contractile calcium in cardiac muscle is released from stores in the sarcoplasmic reticulum (SR), by a process of calcium-induced calcium release (CICR) through ryanodine receptors. Because CICR is intrinsically self-reinforcing, the stability of and graded regulation of cardiac EC coupling appear paradoxical. It is now well established that this gradation results from the stochastic recruitment of varying numbers of elementary local release events, which may themselves be regenerative, and which can be directly observed as calcium sparks. Ryanodine receptors (RyRs) are clustered in dense lattices, and most calcium sparks are now believed to involve activation of multiple RyRs. This implies that local CICR is regenerative, requiring a mechanism to terminate it. It was initially assumed that this mechanism was inactivation of the RyR, but during the decade since the discovery of sparks, no sufficiently strong inactivation mechanism has been demonstrated in vitro and all empirically determined gating schemes for the RyR give unstable EC coupling in Monte Carlo simulations. We consider here possible release termination mechanisms. Stochastic attrition is the spontaneous decay of active clusters due to random channel closure; calculations show that it is much too slow unless assisted by another process. Calcium-dependent RyR inactivation involving third-party proteins remains a viable but speculative mechanism; current candidates include calmodulin and sorcin. Local depletion of SR release terminal calcium could terminate release, however calculations and measurements leave it uncertain whether a sufficient diffusion resistance exists within the SR to sustain such depletion. Depletion could be assisted by dependence of RyR activity on SR lumenal [Ca(2+)]. There is substantial evidence for such lumenal activation, but it is not clear if it is a strong enough effect to account for the robust termination of sparks. The existence of direct interactions among clustered RyRs might account for the discrepancy between the inactivation properties of isolated RyRs and intact clusters. Such coupled gating remains controversial. Determining the mechanism of release termination is the outstanding unsolved problem of cardiac EC coupling, and will probably require extensive genetic manipulation of the EC coupling apparatus in its native environment to unravel the solution.

Little composite dark matter.

PubMed

Balkin, Reuven; Perez, Gilad; Weiler, Andreas

2018-01-01

We examine the dark matter phenomenology of a composite electroweak singlet state. This singlet belongs to the Goldstone sector of a well-motivated extension of the Littlest Higgs with T -parity. A viable parameter space, consistent with the observed dark matter relic abundance as well as with the various collider, electroweak precision and dark matter direct detection experimental constraints is found for this scenario. T -parity implies a rich LHC phenomenology, which forms an interesting interplay between conventional natural SUSY type of signals involving third generation quarks and missing energy, from stop-like particle production and decay, and composite Higgs type of signals involving third generation quarks associated with Higgs and electroweak gauge boson, from vector-like top-partners production and decay. The composite features of the dark matter phenomenology allows the composite singlet to produce the correct relic abundance while interacting weakly with the Higgs via the usual Higgs portal coupling [Formula: see text], thus evading direct detection.

Little composite dark matter

NASA Astrophysics Data System (ADS)

Balkin, Reuven; Perez, Gilad; Weiler, Andreas

2018-02-01

We examine the dark matter phenomenology of a composite electroweak singlet state. This singlet belongs to the Goldstone sector of a well-motivated extension of the Littlest Higgs with T-parity. A viable parameter space, consistent with the observed dark matter relic abundance as well as with the various collider, electroweak precision and dark matter direct detection experimental constraints is found for this scenario. T-parity implies a rich LHC phenomenology, which forms an interesting interplay between conventional natural SUSY type of signals involving third generation quarks and missing energy, from stop-like particle production and decay, and composite Higgs type of signals involving third generation quarks associated with Higgs and electroweak gauge boson, from vector-like top-partners production and decay. The composite features of the dark matter phenomenology allows the composite singlet to produce the correct relic abundance while interacting weakly with the Higgs via the usual Higgs portal coupling λ _{ {DM}}˜ O(1%), thus evading direct detection.

Carrier-envelope phase dependence of the directional fragmentation and hydrogen migration in toluene in few-cycle laser fields

PubMed Central

Li, Hui; Kling, Nora G.; Förg, Benjamin; Stierle, Johannes; Kessel, Alexander; Trushin, Sergei A.; Kling, Matthias F.; Kaziannis, Spyros

2016-01-01

The dissociative ionization of toluene initiated by a few-cycle laser pulse as a function of the carrier envelope phase (CEP) is investigated using single-shot velocity map imaging. Several ionic fragments, CH3+, H2+, and H3+, originating from multiply charged toluene ions present a CEP-dependent directional emission. The formation of H2+ and H3+ involves breaking C-H bonds and forming new bonds between the hydrogen atoms within the transient structure of the multiply charged precursor. We observe appreciable intensity-dependent CEP-offsets. The experimental data are interpreted with a mechanism that involves laser-induced coupling of vibrational states, which has been found to play a role in the CEP-control of molecular processes in hydrocarbon molecules, and appears to be of general importance for such complex molecules. PMID:26958589

Next-to-next-to-leading order gravitational spin-squared potential via the effective field theory for spinning objects in the post-Newtonian scheme

DOE Office of Scientific and Technical Information (OSTI.GOV)

Levi, Michele; Steinhoff, Jan, E-mail: michele.levi@upmc.fr, E-mail: jan.steinhoff@aei.mpg.de

2016-01-01

The next-to-next-to-leading order spin-squared interaction potential for generic compact binaries is derived for the first time via the effective field theory for gravitating spinning objects in the post-Newtonian scheme. The spin-squared sector is an intricate one, as it requires the consideration of the point particle action beyond minimal coupling, and mainly involves the spin-squared worldline couplings, which are quite complex, compared to the worldline couplings from the minimal coupling part of the action. This sector also involves the linear in spin couplings, as we go up in the nonlinearity of the interaction, and in the loop order. Hence, there ismore » an excessive increase in the number of Feynman diagrams, of which more are higher loop ones. We provide all the Feynman diagrams and their values. The beneficial ''nonrelativistic gravitational'' fields are employed in the computation. This spin-squared correction, which enters at the fourth post-Newtonian order for rapidly rotating compact objects, completes the conservative sector up to the fourth post-Newtonian accuracy. The robustness of the effective field theory for gravitating spinning objects is shown here once again, as demonstrated in a recent series of papers by the authors, which obtained all spin dependent sectors, required up to the fourth post-Newtonian accuracy. The effective field theory of spinning objects allows to directly obtain the equations of motion, and the Hamiltonians, and these will be derived for the potential obtained here in a forthcoming paper.« less

An energy-filtering device coupled to a quadrupole mass spectrometer for soft-landing molecular ions on surfaces with controlled energy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bodin, A.; Laloo, R.; Abeilhou, P.

2013-09-15

We have developed an energy-filtering device coupled to a quadrupole mass spectrometer to deposit ionized molecules on surfaces with controlled energy in ultra high vacuum environment. Extensive numerical simulations as well as direct measurements show that the ion beam flying out of a quadrupole exhibits a high-energy tail decreasing slowly up to several hundred eV. This energy distribution renders impossible any direct soft-landing deposition of molecular ions. To remove this high-energy tail by energy filtering, a 127° electrostatic sector and a specific triplet lenses were designed and added after the last quadrupole of a triple quadrupole mass spectrometer. The resultsmore » obtained with this energy-filtering device show clearly the elimination of the high-energy tail. The ion beam that impinges on the sample surface satisfies now the soft-landing criterion for molecular ions, opening new research opportunities in the numerous scientific domains involving charges adsorbed on insulating surfaces.« less

Microfluidic direct injection method for analysis of urinary 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) using molecularly imprinted polymers coupled on-line with LC-MS/MS.

PubMed

Shah, Kumar A; Peoples, Michael C; Halquist, Matthew S; Rutan, Sarah C; Karnes, H Thomas

2011-01-25

The work described in this paper involves development of a high-throughput on-line microfluidic sample extraction method using capillary micro-columns packed with MIP beads coupled with tandem mass spectrometry for the analysis of urinary NNAL. The method was optimized and matrix effects were evaluated and resolved. The method enabled low sample volume (200 μL) and rapid analysis of urinary NNAL by direct injection onto the microfluidic column packed with molecularly imprinted beads engineered to NNAL. The method was validated according to the FDA bioanalytical method validation guidance. The dynamic range extended from 20.0 to 2500.0 pg/mL with a percent relative error of ±5.9% and a run time of 7.00 min. The lower limit of quantitation was 20.0 pg/mL. The method was used for the analysis of NNAL and NNAL-Gluc concentrations in smokers' urine. Copyright © 2010 Elsevier B.V. All rights reserved.

A digital computer simulation and study of a direct-energy-transfer power-conditioning system

NASA Technical Reports Server (NTRS)

Burns, W. W., III; Owen, H. A., Jr.; Wilson, T. G.; Rodriguez, G. E.; Paulkovich, J.

1975-01-01

An investigation of the behavior of the power-conditioning system as a whole is a necessity to ensure the integrity of the aggregate system in the case of space applications. An approach for conducting such an investigation is considered. A description is given of the application of a general digital analog simulator program to the study of an aggregate power-conditioning system which is being developed for use on the International Ultraviolet Explorer spacecraft. The function of the direct energy transfer system studied involves a coupling of a solar array through a main distribution bus to the spacecraft electrical loads.

Study of Fuze Structure and Reliability Design Based on the Direct Search Method

NASA Astrophysics Data System (ADS)

Lin, Zhang; Ning, Wang

2017-03-01

Redundant design is one of the important methods to improve the reliability of the system, but mutual coupling of multiple factors is often involved in the design. In my study, Direct Search Method is introduced into the optimum redundancy configuration for design optimization, in which, the reliability, cost, structural weight and other factors can be taken into account simultaneously, and the redundant allocation and reliability design of aircraft critical system are computed. The results show that this method is convenient and workable, and applicable to the redundancy configurations and optimization of various designs upon appropriate modifications. And this method has a good practical value.

Expanding the Therapy Paradigm with Queer Couples: A Relational Intersectional Lens.

PubMed

Addison, Sheila M; Coolhart, Deborah

2015-09-01

North American and global cultures in general-and the field of Couple and Family Therapy in particular-have made significant strides toward recognizing and validating LGBTQ identities and relationships. However, clinical assessment and conceptualization of queer couples still lack the complexity needed to encompass the issues involved in treatment. Existing literature provides clinicians a basic understanding of queer couples and the dynamics that make them unique from nonqueer couples. However, much of this knowledge has been normed on White middle-class couples and has rarely included couples with transgender or bisexual members. This article invites clinicians and researchers to apply a feminist model of intersectionality to understand queer couples. Our proposed intersectional lens considers multiple axes of identity and power and their interrelationships (Crenshaw, 1989, 1991). We argue that intersectionality is important for understanding all identities, whether privileged or marginalized (Falicov, 2003). This application of the concept of intersectionality is unique in its relational focus, emphasizing how partners' complex individual identities overlap with and intersect with one another. Additionally, this lens considers how the therapists' and clients' multidimensional identities intersect. Three case studies are presented to illustrate application of the intersectional lens. In each case, exploring the partners' multiple social locations, their influences on one another, and the therapist's intersections of identity all proved critical to the direction of therapy. © 2015 Family Process Institute.

Stabilization of Two Radicals with One Metal: A Stepwise Coupling Model for Copper-Catalyzed Radical–Radical Cross-Coupling

PubMed Central

Qi, Xiaotian; Zhu, Lei; Bai, Ruopeng; Lan, Yu

2017-01-01

Transition metal-catalyzed radical–radical cross-coupling reactions provide innovative methods for C–C and C–heteroatom bond construction. A theoretical study was performed to reveal the mechanism and selectivity of the copper-catalyzed C–N radical–radical cross-coupling reaction. The concerted coupling pathway, in which a C–N bond is formed through the direct nucleophilic addition of a carbon radical to the nitrogen atom of the Cu(II)–N species, is demonstrated to be kinetically unfavorable. The stepwise coupling pathway, which involves the combination of a carbon radical with a Cu(II)–N species before C–N bond formation, is shown to be probable. Both the Mulliken atomic spin density distribution and frontier molecular orbital analysis on the Cu(II)–N intermediate show that the Cu site is more reactive than that of N; thus, the carbon radical preferentially react with the metal center. The chemoselectivity of the cross-coupling is also explained by the differences in electron compatibility of the carbon radical, the nitrogen radical and the Cu(II)–N intermediate. The higher activation free energy for N–N radical–radical homo-coupling is attributed to the mismatch of Cu(II)–N species with the nitrogen radical because the electrophilicity for both is strong. PMID:28272407

Multivariate information-theoretic measures reveal directed information structure and task relevant changes in fMRI connectivity.

PubMed

Lizier, Joseph T; Heinzle, Jakob; Horstmann, Annette; Haynes, John-Dylan; Prokopenko, Mikhail

2011-02-01

The human brain undertakes highly sophisticated information processing facilitated by the interaction between its sub-regions. We present a novel method for interregional connectivity analysis, using multivariate extensions to the mutual information and transfer entropy. The method allows us to identify the underlying directed information structure between brain regions, and how that structure changes according to behavioral conditions. This method is distinguished in using asymmetric, multivariate, information-theoretical analysis, which captures not only directional and non-linear relationships, but also collective interactions. Importantly, the method is able to estimate multivariate information measures with only relatively little data. We demonstrate the method to analyze functional magnetic resonance imaging time series to establish the directed information structure between brain regions involved in a visuo-motor tracking task. Importantly, this results in a tiered structure, with known movement planning regions driving visual and motor control regions. Also, we examine the changes in this structure as the difficulty of the tracking task is increased. We find that task difficulty modulates the coupling strength between regions of a cortical network involved in movement planning and between motor cortex and the cerebellum which is involved in the fine-tuning of motor control. It is likely these methods will find utility in identifying interregional structure (and experimentally induced changes in this structure) in other cognitive tasks and data modalities.

New Techniques for Ancient Proteins: Direct Coupling Analysis Applied on Proteins Involved in Iron Sulfur Cluster Biogenesis

PubMed Central

Fantini, Marco; Malinverni, Duccio; De Los Rios, Paolo; Pastore, Annalisa

2017-01-01

Direct coupling analysis (DCA) is a powerful statistical inference tool used to study protein evolution. It was introduced to predict protein folds and protein-protein interactions, and has also been applied to the prediction of entire interactomes. Here, we have used it to analyze three proteins of the iron-sulfur biogenesis machine, an essential metabolic pathway conserved in all organisms. We show that DCA can correctly reproduce structural features of the CyaY/frataxin family (a protein involved in the human disease Friedreich's ataxia) despite being based on the relatively small number of sequences allowed by its genomic distribution. This result gives us confidence in the method. Its application to the iron-sulfur cluster scaffold protein IscU, which has been suggested to function both as an ordered and a disordered form, allows us to distinguish evolutionary traces of the structured species, suggesting that, if present in the cell, the disordered form has not left evolutionary imprinting. We observe instead, for the first time, direct indications of how the protein can dimerize head-to-head and bind 4Fe4S clusters. Analysis of the alternative scaffold protein IscA provides strong support to a coordination of the cluster by a dimeric form rather than a tetramer, as previously suggested. Our analysis also suggests the presence in solution of a mixture of monomeric and dimeric species, and guides us to the prevalent one. Finally, we used DCA to analyze interactions between some of these proteins, and discuss the potentials and limitations of the method. PMID:28664160

Trace analysis of energetic materials via direct analyte-probed nanoextraction coupled to direct analysis in real time mass spectrometry.

PubMed

Clemons, Kristina; Dake, Jeffrey; Sisco, Edward; Verbeck, Guido F

2013-09-10

Direct analysis in real time mass spectrometry (DART-MS) has proven to be a useful forensic tool for the trace analysis of energetic materials. While other techniques for detecting trace amounts of explosives involve extraction, derivatization, solvent exchange, or sample clean-up, DART-MS requires none of these. Typical DART-MS analyses directly from a solid sample or from a swab have been quite successful; however, these methods may not always be an optimal sampling technique in a forensic setting. For example, if the sample were only located in an area which included a latent fingerprint of interest, direct DART-MS analysis or the use of a swab would almost certainly destroy the print. To avoid ruining such potentially invaluable evidence, another method has been developed which will leave the fingerprint virtually untouched. Direct analyte-probed nanoextraction coupled to nanospray ionization-mass spectrometry (DAPNe-NSI-MS) has demonstrated excellent sensitivity and repeatability in forensic analyses of trace amounts of illicit drugs from various types of surfaces. This technique employs a nanomanipulator in conjunction with bright-field microscopy to extract single particles from a surface of interest and has provided a limit of detection of 300 attograms for caffeine. Combining DAPNe with DART-MS provides another level of flexibility in forensic analysis, and has proven to be a sufficient detection method for trinitrotoluene (TNT), RDX, and 1-methylaminoanthraquinone (MAAQ). Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

The establishment and application of direct coupled electrostatic-structural field model in electrostatically controlled deployable membrane antenna

NASA Astrophysics Data System (ADS)

Gu, Yongzhen; Duan, Baoyan; Du, Jingli

2018-05-01

The electrostatically controlled deployable membrane antenna (ECDMA) is a promising space structure due to its low weight, large aperture and high precision characteristics. However, it is an extreme challenge to describe the coupled field between electrostatic and membrane structure accurately. A direct coupled method is applied to solve the coupled problem in this paper. Firstly, the membrane structure and electrostatic field are uniformly described by energy, considering the coupled problem is an energy conservation phenomenon. Then the direct coupled electrostatic-structural field governing equilibrium equations are obtained by energy variation approach. Numerical results show that the direct coupled method improves the computing efficiency by 36% compared with the traditional indirect coupled method with the same level accuracy. Finally, the prototype has been manufactured and tested and the ECDMA finite element simulations show good agreement with the experiment results as the maximum surface error difference is 6%.

Evaluation of aerodynamic characteristics of a coupled fluid-structure system using generalized Bernoulli’s principle: An application to vocal folds vibration

PubMed Central

Zhang, Lucy T.; Yang, Jubiao

2017-01-01

In this work we explore the aerodynamics flow characteristics of a coupled fluid-structure interaction system using a generalized Bernoulli equation derived directly from the Cauchy momentum equations. Unlike the conventional Bernoulli equation where incompressible, inviscid, and steady flow conditions are assumed, this generalized Bernoulli equation includes the contributions from compressibility, viscous, and unsteadiness, which could be essential in defining aerodynamic characteristics. The application of the derived Bernoulli’s principle is on a fully-coupled fluid-structure interaction simulation of the vocal folds vibration. The coupled system is simulated using the immersed finite element method where compressible Navier-Stokes equations are used to describe the air and an elastic pliable structure to describe the vocal fold. The vibration of the vocal fold works to open and close the glottal flow. The aerodynamics flow characteristics are evaluated using the derived Bernoulli’s principles for a vibration cycle in a carefully partitioned control volume based on the moving structure. The results agree very well to experimental observations, which validate the strategy and its use in other types of flow characteristics that involve coupled fluid-structure interactions. PMID:29527541

CFD-CAA Coupled Calculations of a Tandem Cylinder Configuration to Assess Facility Installation Effects

NASA Technical Reports Server (NTRS)

Redonnet, Stephane; Lockard, David P.; Khorrami, Mehdi R.; Choudhari, Meelan M.

2011-01-01

This paper presents a numerical assessment of acoustic installation effects in the tandem cylinder (TC) experiments conducted in the NASA Langley Quiet Flow Facility (QFF), an open-jet, anechoic wind tunnel. Calculations that couple the Computational Fluid Dynamics (CFD) and Computational Aeroacoustics (CAA) of the TC configuration within the QFF are conducted using the CFD simulation results previously obtained at NASA LaRC. The coupled simulations enable the assessment of installation effects associated with several specific features in the QFF facility that may have impacted the measured acoustic signature during the experiment. The CFD-CAA coupling is based on CFD data along a suitably chosen surface, and employs a technique that was recently improved to account for installed configurations involving acoustic backscatter into the CFD domain. First, a CFD-CAA calculation is conducted for an isolated TC configuration to assess the coupling approach, as well as to generate a reference solution for subsequent assessments of QFF installation effects. Direct comparisons between the CFD-CAA calculations associated with the various installed configurations allow the assessment of the effects of each component (nozzle, collector, etc.) or feature (confined vs. free jet flow, etc.) characterizing the NASA LaRC QFF facility.

Evaluation of aerodynamic characteristics of a coupled fluid-structure system using generalized Bernoulli's principle: An application to vocal folds vibration.

PubMed

Zhang, Lucy T; Yang, Jubiao

2016-12-01

In this work we explore the aerodynamics flow characteristics of a coupled fluid-structure interaction system using a generalized Bernoulli equation derived directly from the Cauchy momentum equations. Unlike the conventional Bernoulli equation where incompressible, inviscid, and steady flow conditions are assumed, this generalized Bernoulli equation includes the contributions from compressibility, viscous, and unsteadiness, which could be essential in defining aerodynamic characteristics. The application of the derived Bernoulli's principle is on a fully-coupled fluid-structure interaction simulation of the vocal folds vibration. The coupled system is simulated using the immersed finite element method where compressible Navier-Stokes equations are used to describe the air and an elastic pliable structure to describe the vocal fold. The vibration of the vocal fold works to open and close the glottal flow. The aerodynamics flow characteristics are evaluated using the derived Bernoulli's principles for a vibration cycle in a carefully partitioned control volume based on the moving structure. The results agree very well to experimental observations, which validate the strategy and its use in other types of flow characteristics that involve coupled fluid-structure interactions.

Factors Associated with Involvement in Marriage Preparation Programs

ERIC Educational Resources Information Center

Duncan, Stephen F.; Holman, Thomas B.; Yang, Chongming

2007-01-01

Little is known empirically about the characteristics of couples who do and do not participate in marriage preparation. This study assessed the individual, couple, family, and sociocultural context variables that distinguish couples who become involved in marriage preparation from those who do not, using a sample of 7,331 couples. The results…

Sensorimotor integration: basic concepts, abnormalities related to movement disorders and sensorimotor training-induced cortical reorganization.

PubMed

Machado, Sergio; Cunha, Marlo; Velasques, Bruna; Minc, Daniel; Teixeira, Silmar; Domingues, Clayton A; Silva, Julio G; Bastos, Victor H; Budde, Henning; Cagy, Mauricio; Basile, Luis; Piedade, Roberto; Ribeiro, Pedro

2010-10-01

Sensorimotor integration is defined as the capability of the central nervous system to integrate different sources of stimuli, and parallelly, to transform such inputs in motor actions. To review the basic principles of sensorimotor integration, such as, its neural bases and its elementary mechanisms involved in specific goal-directed tasks performed by healthy subjects, and the abnormalities reported in the most common movement disorders, such as, Parkinson' disease, dystonia and stroke, like the cortical reorganization-related mechanisms. Whether these disorders are associated with an abnormal peripheral sensory input or defective central processing is still unclear, but most of the data support a central mechanism. We found that the sensorimotor integration process plays a potential role in elementary mechanisms involved in specific goal-directed tasks performed by healthy subjects and in occurrence of abnormalities in most common movement disorders and, moreover, play a potential role on the acquisition of abilities that have as critical factor the coupling of different sensory data which will constitute the basis of elaboration of motor outputs consciously goal-directed.

Electric vehicle drive train with direct coupling transmission

DOEpatents

Tankersley, J.B.; Boothe, R.W.; Konrad, C.E.

1995-04-04

An electric vehicle drive train includes an electric motor and an associated speed sensor, a transmission operable in a speed reduction mode or a direct coupled mode, and a controller responsive to the speed sensor for operating the transmission in the speed reduction mode when the motor is below a predetermined value, and for operating the motor in the direct coupled mode when the motor speed is above a predetermined value. The controller reduces the speed of the motor, such as by regeneratively braking the motor, when changing from the speed reduction mode to the direct coupled mode. The motor speed may be increased when changing from the direct coupled mode to the speed reduction mode. The transmission is preferably a single stage planetary gearbox. 6 figures.

Electric vehicle drive train with direct coupling transmission

DOEpatents

Tankersley, Jerome B.; Boothe, Richard W.; Konrad, Charles E.

1995-01-01

An electric vehicle drive train includes an electric motor and an associated speed sensor, a transmission operable in a speed reduction mode or a direct coupled mode, and a controller responsive to the speed sensor for operating the transmission in the speed reduction mode when the motor is below a predetermined value, and for operating the motor in the direct coupled mode when the motor speed is above a predetermined value. The controller reduces the speed of the motor, such as by regeneratively braking the motor, when changing from the speed reduction mode to the direct coupled mode. The motor speed may be increased when changing from the direct coupled mode to the speed reduction mode. The transmission is preferably a single stage planetary gearbox.

The actin cytoskeleton in store-mediated calcium entry

PubMed Central

Rosado, Juan A; Sage, Stewart O

2000-01-01

Store-mediated Ca2+ entry is the main pathway for Ca2+ influx in platelets and many other cells. Several hypotheses have considered both direct and indirect coupling mechanisms between the endoplasmic reticulum and the plasma membrane. Here we pay particular attention to new insights into the regulation of store-mediated Ca2+ entry: the role of the cytoskeleton in a secretion-like coupling model. In this model, Ca2+ entry may be mediated by a reversible trafficking and coupling of the endoplasmic reticulum with the plasma membrane, that shows close parallels to the events mediating secretion. As with secretion, the actin cytoskeleton plays an inhibitory role in the activation of Ca2+ entry by preventing the approach and coupling of the endoplasmic reticulum with the plasma membrane, making cytoskeletal remodelling a key event in the activation of Ca2+ entry. We also review recent advances investigating the regulation of store-mediated Ca2+ entry by small GTPases and phosphoinositides, which might be involved in the store-mediated Ca2+ entry pathway through roles in the remodelling of the cytoskeleton. PMID:10896713

Integrated modeling and analysis of the multiple electromechanical couplings for the direct driven feed system in machine tools

NASA Astrophysics Data System (ADS)

Yang, Xiaojun; Lu, Dun; Liu, Hui; Zhao, Wanhua

2018-06-01

The complicated electromechanical coupling phenomena due to different kinds of causes have significant influences on the dynamic precision of the direct driven feed system in machine tools. In this paper, a novel integrated modeling and analysis method of the multiple electromechanical couplings for the direct driven feed system in machine tools is presented. At first, four different kinds of electromechanical coupling phenomena in the direct driven feed system are analyzed systematically. Then a novel integrated modeling and analysis method of the electromechanical coupling which is influenced by multiple factors is put forward. In addition, the effects of multiple electromechanical couplings on the dynamic precision of the feed system and their main influencing factors are compared and discussed, respectively. Finally, the results of modeling and analysis are verified by the experiments. It finds out that multiple electromechanical coupling loops, which are overlapped and influenced by each other, are the main reasons of the displacement fluctuations in the direct driven feed system.

Reversible and dissipative macroscopic contributions to the stress tensor: active or passive?

PubMed

Brand, H R; Pleiner, H; Svenšek, D

2014-09-01

The issue of dynamic contributions to the macroscopic stress tensor has been of high interest in the field of bio-inspired active systems over the last few years. Of particular interest is a direct coupling ("active term") of the stress tensor with the order parameter, the latter describing orientational order induced by active processes. Here we analyze more generally possible reversible and irreversible dynamic contributions to the stress tensor for various passive and active macroscopic systems. This includes systems with tetrahedral/octupolar order, polar and non-polar (chiral) nematic and smectic liquid crystals, as well as active fluids with a dynamic preferred (polar or non-polar) direction. We show that it cannot a priori be seen, neither from the symmetry properties of the macroscopic variables involved, nor from the structure of the cross-coupling contributions to the stress tensor, whether the system studied is active or passive. Rather, that depends on whether the variables that give rise to those cross-couplings in the stress tensor are driven or not. We demonstrate that several simplified descriptions of active systems in the literature that neglect the necessary counter term to the active term violate linear irreversible thermodynamics and lead to an unphysical contribution to the entropy production.

Self-assembly of multiferroic core-shell particulate nanocomposites through DNA-DNA hybridization and magnetic field directed assembly of superstructures

NASA Astrophysics Data System (ADS)

Sreenivasulu, Gollapudi; Lochbiler, Thomas A.; Panda, Manashi; Srinivasan, Gopalan; Chavez, Ferman A.

2016-04-01

Multiferroic composites of ferromagnetic and ferroelectric phases are of importance for studies on mechanical strain mediated coupling between the magnetic and electric subsystems. This work is on DNA-assisted self-assembly of superstructures of such composites with nanometer periodicity. The synthesis involved oligomeric DNA-functionalized ferroelectric and ferromagnetic nanoparticles, 600 nm BaTiO3 (BTO) and 200 nm NiFe2O4 (NFO), respectively. Mixing BTO and NFO particles, possessing complementary DNA sequences, resulted in the formation of ordered core-shell heteronanocomposites held together by DNA hybridization. The composites were imaged by scanning electron microscopy and scanning microwave microscopy. The presence of heteroassemblies along with core-shell architecture is clearly observed. The reversible nature of the DNA hybridization allows for restructuring the composites into mm-long linear chains and 2D-arrays in the presence of a static magnetic field and ring-like structures in a rotating-magnetic field. Strong magneto-electric (ME) coupling in as-assembled composites is evident from static magnetic field H induced polarization and low-frequency magnetoelectric voltage coefficient measurements. Upon annealing the nanocomposites at high temperatures, evidence for the formation of bulk composites with excellent cross-coupling between the electric and magnetic subsystems is obtained by H-induced polarization and low-frequency ME voltage coefficient. The ME coupling strength in the self-assembled composites is measured to be much stronger than in bulk composites with randomly distributed NFO and BTO prepared by direct mixing and sintering.

The direct arylation of allylic sp3 C-H bonds via organic and photoredox catalysis

NASA Astrophysics Data System (ADS)

Cuthbertson, James D.; MacMillan, David W. C.

2015-03-01

The direct functionalization of unactivated sp3 C-H bonds is still one of the most challenging problems facing synthetic organic chemists. The appeal of such transformations derives from their capacity to facilitate the construction of complex organic molecules via the coupling of simple and otherwise inert building blocks, without introducing extraneous functional groups. Despite notable recent efforts, the establishment of general and mild strategies for the engagement of sp3 C-H bonds in C-C bond forming reactions has proved difficult. Within this context, the discovery of chemical transformations that are able to directly functionalize allylic methyl, methylene and methine carbons in a catalytic manner is a priority. Although protocols for direct oxidation and amination of allylic C-H bonds (that is, C-H bonds where an adjacent carbon is involved in a C = C bond) have become widely established, the engagement of allylic substrates in C-C bond forming reactions has thus far required the use of pre-functionalized coupling partners. In particular, the direct arylation of non-functionalized allylic systems would enable access to a series of known pharmacophores (molecular features responsible for a drug's action), though a general solution to this long-standing challenge remains elusive. Here we report the use of both photoredox and organic catalysis to accomplish a mild, broadly effective direct allylic C-H arylation. This C-C bond forming reaction readily accommodates a broad range of alkene and electron-deficient arene reactants, and has been used in the direct arylation of benzylic C-H bonds.

The direct arylation of allylic sp(3) C-H bonds via organic and photoredox catalysis.

PubMed

Cuthbertson, James D; MacMillan, David W C

2015-03-05

The direct functionalization of unactivated sp(3) C-H bonds is still one of the most challenging problems facing synthetic organic chemists. The appeal of such transformations derives from their capacity to facilitate the construction of complex organic molecules via the coupling of simple and otherwise inert building blocks, without introducing extraneous functional groups. Despite notable recent efforts, the establishment of general and mild strategies for the engagement of sp(3) C-H bonds in C-C bond forming reactions has proved difficult. Within this context, the discovery of chemical transformations that are able to directly functionalize allylic methyl, methylene and methine carbons in a catalytic manner is a priority. Although protocols for direct oxidation and amination of allylic C-H bonds (that is, C-H bonds where an adjacent carbon is involved in a C = C bond) have become widely established, the engagement of allylic substrates in C-C bond forming reactions has thus far required the use of pre-functionalized coupling partners. In particular, the direct arylation of non-functionalized allylic systems would enable access to a series of known pharmacophores (molecular features responsible for a drug's action), though a general solution to this long-standing challenge remains elusive. Here we report the use of both photoredox and organic catalysis to accomplish a mild, broadly effective direct allylic C-H arylation. This C-C bond forming reaction readily accommodates a broad range of alkene and electron-deficient arene reactants, and has been used in the direct arylation of benzylic C-H bonds.

Identification of coupling direction: Application to cardiorespiratory interaction

NASA Astrophysics Data System (ADS)

Rosenblum, Michael G.; Cimponeriu, Laura; Bezerianos, Anastasios; Patzak, Andreas; Mrowka, Ralf

2002-04-01

We consider the problem of experimental detection of directionality of weak coupling between two self-sustained oscillators from bivariate data. We further develop the method introduced by Rosenblum and Pikovsky [Phys. Rev. E 64, 045202 (2001)], suggesting an alternative approach. Next, we consider another framework for identification of directionality, based on the idea of mutual predictability. Our algorithms provide directionality index that shows whether the coupling between the oscillators is unidirectional or bidirectional, and quantifies the asymmetry of bidirectional coupling. We demonstrate the efficiency of three different algorithms in determination of directionality index from short and noisy data. These techniques are then applied to analysis of cardiorespiratory interaction in healthy infants. The results reveal that the direction of coupling between cardiovascular and respiratory systems varies with the age within the first 6 months of life. We find a tendency to change from nearly symmetric bidirectional interaction to nearly unidirectional one (from respiration to the cardiovascular system).

Design optimization for a wearable, gamma-ray and neutron sensitive, detector array with directionality estimation

NASA Astrophysics Data System (ADS)

Ayaz-Maierhafer, Birsen; Britt, Carl G.; August, Andrew J.; Qi, Hairong; Seifert, Carolyn E.; Hayward, Jason P.

2017-10-01

In this study, we report on a constrained optimization and tradeoff study of a hybrid, wearable detector array having directional sensing based upon gamma-ray occlusion. One resulting design uses CLYC detectors while the second feasibility design involves the coupling of gamma-ray-sensitive CsI scintillators and a rubber LiCaAlF6 (LiCAF) neutron detector. The detector systems' responses were investigated through simulation as a function of angle in a two-dimensional plane. The expected total counts, peak-to-total ratio, directionality performance, and detection of 40 K for accurate gain stabilization were considered in the optimization. Source directionality estimation was investigated using Bayesian algorithms. Gamma-ray energies of 122 keV, 662 keV, and 1332 keV were considered. The equivalent neutron capture response compared with 3 He was also investigated for both designs.

Joint Services Electronics Program: Electronics Research at the University of Texas at Austin

DTIC Science & Technology

1990-12-31

large area 2-dimensional phased arrays , and improved beam qualities . This device structure is expected to impact laser technology over a wide range...energy. In the following pages we report on two significant accomplishments. The first involves the influence oi mirror-quantum well optical coupling on... intensity enhancements in the normal direction to the mirror of a 24 (Research Unit SSE89-1, "Growth of Ill-V Compounds by Molecular Beam Epitaxy") factor of

Large eddy simulations and direct numerical simulations of high speed turbulent reacting flows

NASA Technical Reports Server (NTRS)

Givi, Peyman; Madnia, Cyrus K.; Steinberger, Craig J.

1990-01-01

This research is involved with the implementation of advanced computational schemes based on large eddy simulations (LES) and direct numerical simulations (DNS) to study the phenomenon of mixing and its coupling with chemical reactions in compressible turbulent flows. In the efforts related to LES, a research program to extend the present capabilities of this method was initiated for the treatment of chemically reacting flows. In the DNS efforts, the focus is on detailed investigations of the effects of compressibility, heat release, and non-equilibrium kinetics modelings in high speed reacting flows. Emphasis was on the simulations of simple flows, namely homogeneous compressible flows, and temporally developing high speed mixing layers.

Revealing Nanostructures through Plasmon Polarimetry.

PubMed

Kleemann, Marie-Elena; Mertens, Jan; Zheng, Xuezhi; Cormier, Sean; Turek, Vladimir; Benz, Felix; Chikkaraddy, Rohit; Deacon, William; Lombardi, Anna; Moshchalkov, Victor V; Vandenbosch, Guy A E; Baumberg, Jeremy J

2017-01-24

Polarized optical dark-field spectroscopy is shown to be a versatile noninvasive probe of plasmonic structures that trap light to the nanoscale. Clear spectral polarization splittings are found to be directly related to the asymmetric morphology of nanocavities formed between faceted gold nanoparticles and an underlying gold substrate. Both experiment and simulation show the influence of geometry on the coupled system, with spectral shifts Δλ = 3 nm from single atoms. Analytical models allow us to identify the split resonances as transverse cavity modes, tightly confined to the nanogap. The direct correlation of resonance splitting with atomistic morphology allows mapping of subnanometre structures, which is crucial for progress in extreme nano-optics involving chemistry, nanophotonics, and quantum devices.

Wave steering effects in anisotropic composite structures: Direct calculation of the energy skew angle through a finite element scheme.

PubMed

Chronopoulos, D

2017-01-01

A systematic expression quantifying the wave energy skewing phenomenon as a function of the mechanical characteristics of a non-isotropic structure is derived in this study. A structure of arbitrary anisotropy, layering and geometric complexity is modelled through Finite Elements (FEs) coupled to a periodic structure wave scheme. A generic approach for efficiently computing the angular sensitivity of the wave slowness for each wave type, direction and frequency is presented. The approach does not involve any finite differentiation scheme and is therefore computationally efficient and not prone to the associated numerical errors. Copyright © 2016 Elsevier B.V. All rights reserved.

The novel fluorescent CDP-analogue (Pbeta)MABA-CDP is a specific probe for the NMP binding site of UMP/CMP kinase.

PubMed

Rudolph, M G; Veit, T J; Reinstein, J

1999-12-01

Direct thermodynamic and kinetic investigations of the binding of nucleotides to the nucleoside monophosphate (NMP) site of NMP kinases have not been possible so far because a spectroscopic probe was not available. By coupling a fluorescent N-methylanthraniloyl- (mant) group to the beta-phosphate of CDP via a butyl linker, a CDP analogue [(Pbeta)MABA-CDP] was obtained that still binds specifically to the NMP site of UmpKdicty, because the base and the ribose moieties, which are involved in specific interactions, are not modified. This allows the direct determination of binding constants for its substrates in competition experiments.

The novel fluorescent CDP-analogue (Pbeta)MABA-CDP is a specific probe for the NMP binding site of UMP/CMP kinase.

PubMed Central

Rudolph, M. G.; Veit, T. J.; Reinstein, J.

1999-01-01

Direct thermodynamic and kinetic investigations of the binding of nucleotides to the nucleoside monophosphate (NMP) site of NMP kinases have not been possible so far because a spectroscopic probe was not available. By coupling a fluorescent N-methylanthraniloyl- (mant) group to the beta-phosphate of CDP via a butyl linker, a CDP analogue [(Pbeta)MABA-CDP] was obtained that still binds specifically to the NMP site of UmpKdicty, because the base and the ribose moieties, which are involved in specific interactions, are not modified. This allows the direct determination of binding constants for its substrates in competition experiments. PMID:10631985

Vibrational Mode-Specific Autodetachment and Coupling of CH2CN-

NASA Astrophysics Data System (ADS)

Lyle, Justin; Mabbs, Richard

2017-06-01

The Cyanomethyl Anion, CH_{2}CN-, and neutral radical have been studied extensively, with several findings of autodetachment about the totally symmetric transition, as well as high resolution experiments revealing symmetrically forbidden and weak vibrational features. We report photoelectron spectra using the Velocity-Mapped Imaging Technique in 1-2 \\wn increments over a range of 13460 to 15384 \\wn that has not been previously examined. These spectra include excitation of the ground state cyanomethyl anion into the direct detachment thresholds of previously reported vibrational modes for the neutral radical. Significant variations from Franck-Condon behavior were observed in the branching ratios for resolved vibrational features for excitation in the vicinity of the thresholds involving the νb{3} and νb{5} modes. These are consistent with autodetachment from rovibrational levels of a dipole bound state acting as a resonance in the detachment continuum. The autodetachment channels involve single changes in vibrational quantum number, consistent with the vibrational propensity rule but in some cases reveal relaxation to a different vibrational mode indicating coupling between the modes and/or a breakdown of the normal mode approximation.

Automatic Associations Between One's Partner and One's Affect as the Proximal Mechanism of Change in Relationship Satisfaction: Evidence From Evaluative Conditioning.

PubMed

McNulty, James K; Olson, Michael A; Jones, Rachael E; Acosta, Laura M

2017-08-01

The current study examined whether directly altering affective associations involving a relationship partner through evaluative conditioning can lead to changes in relationship satisfaction. Married couples ( N = 144) were asked to view a brief stream of images once every 3 days for 6 weeks. Embedded in this stream were pictures of the partner, which, according to random assignment of couples to experimental group, were paired with either positive or neutral stimuli. Couples also completed measures of automatic partner attitudes and explicit marital satisfaction at baseline and once every 2 weeks for 8 weeks. Spouses who viewed their partners paired with positive stimuli demonstrated more-positive automatic partner attitudes than did control spouses, and these attitudes predicted increased self-reported marital satisfaction over time. These results provide novel evidence for a mechanism of change in relationship satisfaction, represent a step toward documenting how strong attitudes can evolve through passive exposure to information, and suggest novel avenues for relationship interventions.

Dyadic Dynamics in Young Couples Reporting Dating Violence: An Actor-Partner interdependence model

PubMed Central

Paradis, Alison; Hébert, Martine; Fernet, Mylène

2016-01-01

This study uses a combination of observational methods and dyadic data analysis to understand how boyfriends’ and girlfriends’ perpetration of dating violence may shape their own and their partners’ problem-solving communication behaviors. A sample of 39 young heterosexual couples aged between 15 and 20 years (mean age 17.8 years) completed a set of questionnaires and were observed during a 45 minute dyadic interaction, which was coded using the Interactional Dimension Coding System (IDCS). Results suggest that, neither boyfriends nor girlfriends own perpetration of dating violence was related to their display of positive and negative communication behaviors. However, estimates revealed significant partner effects, suggesting that negative communication behaviors displayed by girls and boys and positive communication behavior displayed by girls were associated to their partner’s dating violence but not to their own. Such results confirm the need to shift our focus from an individual perspective to examining dyadic influences and processes involved in the couple system and the bi-directionality of violent relationships. PMID:25969443

Spectral methods for study of the G-protein-coupled receptor rhodopsin. II. Magnetic resonance methods

NASA Astrophysics Data System (ADS)

Struts, A. V.; Barmasov, A. V.; Brown, M. F.

2016-02-01

This article continues our review of spectroscopic studies of G-protein-coupled receptors. Magnetic resonance methods including electron paramagnetic resonance (EPR) and nuclear magnetic resonance (NMR) provide specific structural and dynamical data for the protein in conjunction with optical methods (vibrational, electronic spectroscopy) as discussed in the accompanying article. An additional advantage is the opportunity to explore the receptor proteins in the natural membrane lipid environment. Solid-state 2H and 13C NMR methods yield information about both the local structure and dynamics of the cofactor bound to the protein and its light-induced changes. Complementary site-directed spin-labeling studies monitor the structural alterations over larger distances and correspondingly longer time scales. A multiscale reaction mechanism describes how local changes of the retinal cofactor unlock the receptor to initiate large-scale conformational changes of rhodopsin. Activation of the G-protein-coupled receptor involves an ensemble of conformational substates within the rhodopsin manifold that characterize the dynamically active receptor.

Coupling between Buoyancy Forces and Electroconvective Instability near Ion-Selective Surfaces.

PubMed

Karatay, Elif; Andersen, Mathias Bækbo; Wessling, Matthias; Mani, Ali

2016-05-13

Recent investigations have revealed that ion transport from aqueous electrolytes to ion-selective surfaces is subject to electroconvective instability that stems from coupling of hydrodynamics with electrostatic forces. These systems inherently involve fluid density variation set by salinity gradients. However, the coupling between the buoyancy effects and electroconvective instability has not yet been investigated although a wide range of electrochemical systems are naturally prone to these interplaying effects. In this study we thoroughly examine the interplay of gravitational convection and chaotic electroconvection. Our results reveal that buoyant forces can significantly influence the transport rates, otherwise set by electroconvection, when the Rayleigh number Ra of the system exceeds a value Ra∼1000. We show that buoyancy forces can significantly alter the flow patterns in these systems. When the buoyancy acts in the stabilizing direction, it limits the extent of penetration of electroconvection, but without eliminating it. When the buoyancy destabilizes the flow, it alters the electroconvective patterns by introducing upward and downward fingers of respectively light and heavy fluids.

Alcohol-Focused Behavioral Couple Therapy

PubMed Central

McCrady, Barbara; Wilson, Adam; Muñoz, Rosa; Fink, Brandi; Fokas, Kathryn; Borders, Adrienne

2016-01-01

Alcohol Behavioral Couple Therapy (ABCT) has emerged over the last 30 years as a highly efficacious treatment for those with alcohol use disorders. This review highlights the historical and conceptual underpinnings of ABCT, as well as the specific treatment elements and structure. Proposed active ingredients, moderators, and mediators of treatment outcome are discussed. Efficacy is evaluated for reductions in identified patient drinking, improved relationship functioning, and reductions in intimate partner violence. Adaptations of ABCT for substances other than alcohol are described. Other adaptations, including brief interventions, interventions addressing PTSD and TBI along with alcohol use, and interventions deliverable via technology platforms are described. Additional cost-benefit and cost-effectiveness findings supporting the economic value of ABCT are noted. Future directions for research in this area include possible adaptations for female identified patients, non-traditional couples, LGBT partners and dyads involving non-intimate partner relationships. The development of more flexible models and enhanced dissemination strategies may improve clinical uptake and utility as well as increasing the feasibility of this treatment for integrated healthcare settings. PMID:27369809

Velocity Enhancement by Synchronization of Magnetic Domain Walls

NASA Astrophysics Data System (ADS)

Hrabec, Aleš; Křižáková, Viola; Pizzini, Stefania; Sampaio, João; Thiaville, André; Rohart, Stanislas; Vogel, Jan

2018-06-01

Magnetic domain walls are objects whose dynamics is inseparably connected to their structure. In this Letter, we investigate magnetic bilayers, which are engineered such that a coupled pair of domain walls, one in each layer, is stabilized by a cooperation of Dzyaloshinskii-Moriya interaction and flux-closing mechanism. The dipolar field mediating the interaction between the two domain walls links not only their position but also their structure. We show that this link has a direct impact on their magnetic-field-induced dynamics. We demonstrate that in such a system the coupling leads to an increased domain wall velocity with respect to single domain walls. Since the domain wall dynamics is observed in a precessional regime, the dynamics involves the synchronization between the two walls to preserve the flux closure during motion. Properties of these coupled oscillating walls can be tuned by an additional in-plane magnetic field enabling a rich variety of states, from perfect synchronization to complete detuning.

Alcohol-Focused Behavioral Couple Therapy.

PubMed

McCrady, Barbara S; Wilson, Adam D; Muñoz, Rosa E; Fink, Brandi C; Fokas, Kathryn; Borders, Adrienne

2016-09-01

Alcohol Behavioral Couple Therapy (ABCT) has emerged over the last 30 years as a highly efficacious treatment for those with alcohol use disorders. This review highlights the historical and conceptual underpinnings of ABCT, as well as the specific treatment elements and structure. Proposed active ingredients, moderators, and mediators of treatment outcome are discussed. Efficacy is evaluated for reductions in identified patient drinking, improved relationship functioning, and reductions in intimate partner violence. Adaptations of ABCT for substances other than alcohol are described. Other adaptations, including brief interventions, interventions addressing PTSD and TBI along with alcohol use, and interventions deliverable via technology platforms are described. Additional cost-benefit and cost-effectiveness findings supporting the economic value of ABCT are noted. Future directions for research in this area include possible adaptations for female identified patients, nontraditional couples, LGBT partners and dyads involving nonintimate partner relationships. The development of more flexible models and enhanced dissemination strategies may improve clinical uptake and utility as well as increasing the feasibility of this treatment for integrated healthcare settings. © 2016 Family Process Institute.

Understanding the Asian summer monsoon response to greenhouse warming: the relative roles of direct radiative forcing and sea surface temperature change

NASA Astrophysics Data System (ADS)

Li, Xiaoqiong; Ting, Mingfang

2017-10-01

Future hydroclimate projections from state-of-the-art climate models show large uncertainty and model spread, particularly in the tropics and over the monsoon regions. The precipitation and circulation responses to rising greenhouse gases involve a fast component associated with direct radiative forcing and a slow component associated with sea surface temperature (SST) warming; the relative importance of the two may contribute to model discrepancies. In this study, regional hydroclimate responses to greenhouse warming are assessed using output from coupled general circulation models in the Coupled Model Intercomparison Project-Phase 5 (CMIP5) and idealized atmospheric general circulation model experiments from the Atmosphere Model Intercomparison Project. The thermodynamic and dynamic mechanisms causing the rainfall changes are examined using moisture budget analysis. Results show that direct radiative forcing and SST change exert significantly different responses both over land and ocean. For most part of the Asian monsoon region, the summertime rainfall changes are dominated by the direct CO2 radiative effect through enhanced monsoon circulation. The response to SST warming shows a larger model spread compared to direct radiative forcing, possibly due to the cancellation between the thermodynamical and dynamical components. While the thermodynamical response of the Asian monsoon is robust across the models, there is a lack of consensus for the dynamical response among the models and weak multi-model mean responses in the CMIP5 ensemble, which may be related to the multiple physical processes evolving on different time scales.

Direct Involvement of the Master Nitrogen Metabolism Regulator GlnR in Antibiotic Biosynthesis in Streptomyces.

PubMed

He, Juan-Mei; Zhu, Hong; Zheng, Guo-Song; Liu, Pan-Pan; Wang, Jin; Zhao, Guo-Ping; Zhu, Guo-Qiang; Jiang, Wei-Hong; Lu, Yin-Hua

2016-12-16

GlnR, an OmpR-like orphan two-component system response regulator, is a master regulator of nitrogen metabolism in the genus Streptomyces In this work, evidence that GlnR is also directly involved in the regulation of antibiotic biosynthesis is provided. In the model strain Streptomyces coelicolor M145, an in-frame deletion of glnR resulted in markedly increased actinorhodin (ACT) production but reduced undecylprodigiosin (RED) biosynthesis when exposed to R2YE culture medium. Transcriptional analysis coupled with DNA binding studies revealed that GlnR represses ACT but activates RED production directly via the pathway-specific activator genes actII-ORF4 and redZ, respectively. The precise GlnR-binding sites upstream of these two target genes were defined. In addition, the direct involvement of GlnR in antibiotic biosynthesis was further identified in Streptomyces avermitilis, which produces the important anthelmintic agent avermectin. We found that S. avermitilis GlnR (GlnRsav) could stimulate avermectin but repress oligomycin production directly through the respective pathway-specific activator genes, aveR and olmRI/RII To the best of our knowledge, this report describes the first experimental evidence demonstrating that GlnR regulates antibiotic biosynthesis directly through pathway-specific regulators in Streptomyces Our results suggest that GlnR-mediated regulation of antibiotic biosynthesis is likely to be universal in streptomycetes. These findings also indicate that GlnR is not only a master nitrogen regulator but also an important controller of secondary metabolism, which may help to balance nitrogen metabolism and antibiotic biosynthesis in streptomycetes. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

Enhancement of coupling ratios in SOI based asymmetrical optical directional couplers

NASA Astrophysics Data System (ADS)

Pendam, Nagaraju; Vardhani, Chunduru Parvatha

2017-11-01

A novel design of slab structured asymmetrical optical directional coupler with S-bend waveguides on silicon-on-insulator (SOI) platform has been designed by using R-Soft CAD tool. Beam propagation method (BPM) is used for light propagation analysis. The simulation results of asymmetrical optical directional couplers are reported. We find that the asymmetrical directional coupler has lower coupling ratios and higher extinction ratios with waveguide parameters such as width, wavelength, waveguide spacing, and coupling length. Simulation results designate that the coupling efficiency for transverse electric (TE) and transverse magnetic (TM) modes can reach about more than 95% and extinction ratio about 6 dB when the coupling length is 6 mm for both the polarization modes and insertion loss is 17 dB with same coupling length 6 mm at central wavelength 1550 nm.

Couple Relationship Quality, Coparenting, and Fathering in Taiwan

ERIC Educational Resources Information Center

Chen, Hui-Hua

2013-01-01

This study examined connections among couple relationship quality, coparenting, and mother and father involvement in 100 families from urban Central Taiwan. Fathers and mothers with at least one school-age child completed questionnaires regarding their couple satisfaction and consensus, coparenting techniques and consistency, and involvement in…

Assimilating concentration observations for transport and dispersion modeling in a meandering wind field

NASA Astrophysics Data System (ADS)

Haupt, Sue Ellen; Beyer-Lout, Anke; Long, Kerrie J.; Young, George S.

Assimilating concentration data into an atmospheric transport and dispersion model can provide information to improve downwind concentration forecasts. The forecast model is typically a one-way coupled set of equations: the meteorological equations impact the concentration, but the concentration does not generally affect the meteorological field. Thus, indirect methods of using concentration data to influence the meteorological variables are required. The problem studied here involves a simple wind field forcing Gaussian dispersion. Two methods of assimilating concentration data to infer the wind direction are demonstrated. The first method is Lagrangian in nature and treats the puff as an entity using feature extraction coupled with nudging. The second method is an Eulerian field approach akin to traditional variational approaches, but minimizes the error by using a genetic algorithm (GA) to directly optimize the match between observations and predictions. Both methods show success at inferring the wind field. The GA-variational method, however, is more accurate but requires more computational time. Dynamic assimilation of a continuous release modeled by a Gaussian plume is also demonstrated using the genetic algorithm approach.

Self-consistent Dark Matter simplified models with an s-channel scalar mediator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bell, Nicole F.; Busoni, Giorgio; Sanderson, Isaac W., E-mail: n.bell@unimelb.edu.au, E-mail: giorgio.busoni@unimelb.edu.au, E-mail: isanderson@student.unimelb.edu.au

We examine Simplified Models in which fermionic DM interacts with Standard Model (SM) fermions via the exchange of an s -channel scalar mediator. The single-mediator version of this model is not gauge invariant, and instead we must consider models with two scalar mediators which mix and interfere. The minimal gauge invariant scenario involves the mixing of a new singlet scalar with the Standard Model Higgs boson, and is tightly constrained. We construct two Higgs doublet model (2HDM) extensions of this scenario, where the singlet mixes with the 2nd Higgs doublet. Compared with the one doublet model, this provides greater freedommore » for the masses and mixing angle of the scalar mediators, and their coupling to SM fermions. We outline constraints on these models, and discuss Yukawa structures that allow enhanced couplings, yet keep potentially dangerous flavour violating processes under control. We examine the direct detection phenomenology of these models, accounting for interference of the scalar mediators, and interference of different quarks in the nucleus. Regions of parameter space consistent with direct detection measurements are determined.« less

Development of a superconducting position sensor for the Satellite Test of the Equivalence Principle

NASA Astrophysics Data System (ADS)

Clavier, Odile Helene

The Satellite Test of the Equivalence Principle (STEP) is a joint NASA/ESA mission that proposes to measure the differential acceleration of two cylindrical test masses orbiting the earth in a drag-free satellite to a precision of 10-18 g. Such an experiment would conceptually reproduce Galileo's tower of Pisa experiment with a much longer time of fall and greatly reduced disturbances. The superconducting test masses are constrained in all degrees of freedom except their axial direction (the sensitive axis) using superconducting bearings. The STEP accelerometer measures the differential position of the masses in their sensitive direction using superconducting inductive pickup coils coupled to an extremely sensitive magnetometer called a DC-SQUID (Superconducting Quantum Interference Device). Position sensor development involves the design, manufacture and calibration of pickup coils that will meet the acceleration sensitivity requirement. Acceleration sensitivity depends on both the displacement sensitivity and stiffness of the position sensor. The stiffness must kept small while maintaining stability of the accelerometer. Using a model for the inductance of the pickup coils versus displacement of the test masses, a computer simulation calculates the sensitivity and stiffness of the accelerometer in its axial direction. This simulation produced a design of pickup coils for the four STEP accelerometers. Manufacture of the pickup coils involves standard photolithography techniques modified for superconducting thin-films. A single-turn pickup coil was manufactured and produced a successful superconducting coil using thin-film Niobium. A low-temperature apparatus was developed with a precision position sensor to measure the displacement of a superconducting plate (acting as a mock test mass) facing the coil. The position sensor was designed to detect five degrees of freedom so that coupling could be taken into account when measuring the translation of the plate relative to the coil. The inductance was measured using a DC-SQUID coupled to the pickup coil. The experimental results agree with the model used in the simulation thereby validating the concept used for the design. The STEP program now has the confidence necessary to design and manufacture a position sensor for the flight accelerometer.

Acetylcholine Release in Prefrontal Cortex Promotes Gamma Oscillations and Theta–Gamma Coupling during Cue Detection

PubMed Central

Hetrick, Vaughn L.; Berke, Joshua D.

2017-01-01

The capacity for using external cues to guide behavior (“cue detection”) constitutes an essential aspect of attention and goal-directed behavior. The cortical cholinergic input system, via phasic increases in prefrontal acetylcholine release, plays an essential role in attention by mediating such cue detection. However, the relationship between cholinergic signaling during cue detection and neural activity dynamics in prefrontal networks remains unclear. Here we combined subsecond measures of cholinergic signaling, neurophysiological recordings, and cholinergic receptor blockade to delineate the cholinergic contributions to prefrontal oscillations during cue detection in rats. We first confirmed that detected cues evoke phasic acetylcholine release. These cholinergic signals were coincident with increased neuronal synchrony across several frequency bands and the emergence of theta–gamma coupling. Muscarinic and nicotinic cholinergic receptors both contributed specifically to gamma synchrony evoked by detected cues, but the effects of blocking the two receptor subtypes were dissociable. Blocking nicotinic receptors primarily attenuated high-gamma oscillations occurring during the earliest phases of the cue detection process, while muscarinic (M1) receptor activity was preferentially involved in the transition from high to low gamma power that followed and corresponded to the mobilization of networks involved in cue-guided decision making. Detected cues also promoted coupling between gamma and theta oscillations, and both nicotinic and muscarinic receptor activity contributed to this process. These results indicate that acetylcholine release coordinates neural oscillations during the process of cue detection. SIGNIFICANCE STATEMENT The capacity of learned cues to direct attention and guide responding (“cue detection”) is a key component of goal-directed behavior. Rhythmic neural activity and increases in acetylcholine release in the prefrontal cortex contribute to this process; however, the relationship between these neuronal mechanisms is not well understood. Using a combination of in vivo neurochemistry, neurophysiology, and pharmacological methods, we demonstrate that cue-evoked acetylcholine release, through distinct actions at both nicotinic and muscarinic receptors, triggers a procession of neural oscillations that map onto the multiple stages of cue detection. Our data offer new insights into cholinergic function by revealing the temporally orchestrated changes in prefrontal network synchrony modulated by acetylcholine release during cue detection. PMID:28213446

Religiosity and Sexual Involvement Within Adolescent Romantic Couples

PubMed Central

LeJeune, Brenna C.; Zimet, Gregory D.; Azzouz, Faouzi; Fortenberry, J. Dennis

2011-01-01

The impact of religiosity in adolescent romantic partnerships on sexual behavior was assessed. Data were obtained from the National Longitudinal Study of Adolescent Health reciprocated couples database using religious- and relationship-oriented variables to predict sexual involvement in 374 couples (748 participants). We found that individual- and couple-based religiosity impacted sexual behavior. These findings provide evidence for dyad religiosity as a component involved in the expression of sexual behavior in romantic relationships. The current results highlight the importance of incorporating a broad social perspective in order to understand the expression of adolescent sexual behavior. PMID:21735321

Bile Acid Signaling Pathways from the Enterohepatic Circulation to the Central Nervous System

PubMed Central

Mertens, Kim L.; Kalsbeek, Andries; Soeters, Maarten R.; Eggink, Hannah M.

2017-01-01

Bile acids are best known as detergents involved in the digestion of lipids. In addition, new data in the last decade have shown that bile acids also function as gut hormones capable of influencing metabolic processes via receptors such as FXR (farnesoid X receptor) and TGR5 (Takeda G protein-coupled receptor 5). These effects of bile acids are not restricted to the gastrointestinal tract, but can affect different tissues throughout the organism. It is still unclear whether these effects also involve signaling of bile acids to the central nervous system (CNS). Bile acid signaling to the CNS encompasses both direct and indirect pathways. Bile acids can act directly in the brain via central FXR and TGR5 signaling. In addition, there are two indirect pathways that involve intermediate agents released upon interaction with bile acids receptors in the gut. Activation of intestinal FXR and TGR5 receptors can result in the release of fibroblast growth factor 19 (FGF19) and glucagon-like peptide 1 (GLP-1), both capable of signaling to the CNS. We conclude that when plasma bile acids levels are high all three pathways may contribute in signal transmission to the CNS. However, under normal physiological circumstances, the indirect pathway involving GLP-1 may evoke the most substantial effect in the brain. PMID:29163019

Elevated atmospheric CO2 negatively impacts photosynthesis through radiative forcing and physiology-mediated climate feedback

NASA Astrophysics Data System (ADS)

Zhu, Peng; Zhuang, Qianlai; Ciais, Philippe; Welp, Lisa; Li, Wenyu; Xin, Qinchuan

2017-02-01

Increasing atmospheric CO2 affects photosynthesis involving directly increasing leaf carboxylation rates, stomatal closure, and climatic effects. The direct effects are generally thought to be positive leading to increased photosynthesis, while its climatic effects can be regionally positive or negative. These effects are usually considered to be independent from each other, but they are in fact coupled through interactions between land surface exchanges of gases and heat and the physical climate system. In particular, stomatal closure reduces evapotranspiration and increases sensible heat emissions from ecosystems, leading to decreased atmospheric moisture and precipitation and local warming. We use a coupled earth system model to attribute the influence of the increase in CO2 on gross primary productivity (GPP) during the period of 1930-2011. In our model, CO2 radiative effects cause climate change that has only a negligible effect on global GPP (a reduction of 0.9 ± 2% during the last 80 years) because of opposite responses between tropical and northern biomes. On the other hand, CO2 physiological effects on GPP are both positive, by increased carboxylation rates and water use efficiency (7.1 ± 0.48% increase), and negative, by vegetation-climate feedback reducing precipitation, as a consequence of decreased transpiration and increased sensible heat in areas without water limitation (2.7 ± 1.76% reduction).When considering the coupled atmosphere-vegetation system, negative climate feedback on photosynthesis and plant growth due to the current level of CO2 opposes 29-38% of the gains from direct fertilization effects.

Insights from a Recent Meeting: Current Status and Future Directions in Magnesium Corrosion Research

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brady, Michael P.; Joost, William J.; David Warren, C.

The United States Department of Energy Vehicle Technologies Office held a Technical Review Meeting entitled “Current Status and Future Directions in Magnesium Corrosion Research” at Oak Ridge National Laboratory in April 2016. Here current funded Mg corrosion projects presented their latest results, along with invited presentations from academic and industrial researchers in the area of Mg corrosion. This paper overviews select topics from the meeting, with an emphasis on relaying meeting discussion points regarding future needs in understanding and mitigating Mg corrosion, particularly for automotive applications. Topics highlighted include the need for pretreatments and coatings suitable for mass vehicle productionmore » of Mg components, particularly for dissimilar metal joints involving Mg, Al, or steel, and corrosion evaluation methods more relevant to automotive components and operating conditions. Finally, from a scientific perspective, the need for better fundamental understanding of Mg dissolution, hydrogen evolution, and film formation behavior was a recurring theme, as was phenomena related to microgalvanic coupling involving second phases and impurities in Mg.« less

Insights from a Recent Meeting: Current Status and Future Directions in Magnesium Corrosion Research

DOE PAGES

Brady, Michael P.; Joost, William J.; David Warren, C.

2016-11-17

The United States Department of Energy Vehicle Technologies Office held a Technical Review Meeting entitled “Current Status and Future Directions in Magnesium Corrosion Research” at Oak Ridge National Laboratory in April 2016. Here current funded Mg corrosion projects presented their latest results, along with invited presentations from academic and industrial researchers in the area of Mg corrosion. This paper overviews select topics from the meeting, with an emphasis on relaying meeting discussion points regarding future needs in understanding and mitigating Mg corrosion, particularly for automotive applications. Topics highlighted include the need for pretreatments and coatings suitable for mass vehicle productionmore » of Mg components, particularly for dissimilar metal joints involving Mg, Al, or steel, and corrosion evaluation methods more relevant to automotive components and operating conditions. Finally, from a scientific perspective, the need for better fundamental understanding of Mg dissolution, hydrogen evolution, and film formation behavior was a recurring theme, as was phenomena related to microgalvanic coupling involving second phases and impurities in Mg.« less

Perceived Threat and Perceived Neglect: Couples' Underlying Concerns during Conflict

ERIC Educational Resources Information Center

Sanford, Keith

2010-01-01

The Couples Underlying Concern Inventory assesses 2 fundamental types of distress that couples experience during interpersonal conflict. "Perceived threat" involves a perception that one's partner is blaming and controlling the self. "Perceived neglect" involves a perception that one's partner is failing to make desired contributions or…

Directivity analysis of meander-line-coil EMATs with a wholly analytical method.

PubMed

Xie, Yuedong; Liu, Zenghua; Yin, Liyuan; Wu, Jiande; Deng, Peng; Yin, Wuliang

2017-01-01

This paper presents the simulation and experimental study of the radiation pattern of a meander-line-coil EMAT. A wholly analytical method, which involves the coupling of two models: an analytical EM model and an analytical UT model, has been developed to build EMAT models and analyse the Rayleigh waves' beam directivity. For a specific sensor configuration, Lorentz forces are calculated using the EM analytical method, which is adapted from the classic Deeds and Dodd solution. The calculated Lorentz force density are imported to an analytical ultrasonic model as driven point sources, which produce the Rayleigh waves within a layered medium. The effect of the length of the meander-line-coil on the Rayleigh waves' beam directivity is analysed quantitatively and verified experimentally. Copyright © 2016 Elsevier B.V. All rights reserved.

Bioelectrochemical systems-driven directional ion transport enables low-energy water desalination, pollutant removal, and resource recovery.

PubMed

Chen, Xi; Liang, Peng; Zhang, Xiaoyuan; Huang, Xia

2016-09-01

Bioelectrochemical systems (BESs) are integrated water treatment technologies that generate electricity using organic matter in wastewater. In situ use of bioelectricity can direct the migration of ionic substances in a BES, thereby enabling water desalination, resource recovery, and valuable substance production. Recently, much attention has been placed on the microbial desalination cells in BESs to drive water desalination, and various configurations have optimized electricity generation and desalination performance and also coupled hydrogen production, heavy metal reduction, and other reactions. In addition, directional transport of other types of charged ions can remediate polluted groundwater, recover nutrient, and produce valuable substances. To better promote the practical application, the use of BESs as directional drivers of ionic substances requires further optimization to improve energy use efficiency and treatment efficacy. This article reviews existing researches on BES-driven directional ion transport to treat wastewater and identifies a few key factors involved in efficiency optimization. Copyright © 2016 Elsevier Ltd. All rights reserved.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rybicki, E.F.; Luiskutty, C.T.; Sutrick, J.S.

This research is part of a larger program sponsored by the United States Department of Energy with the objective of developing better methods to produce gas from low permeability formations in western gas sands. This large research program involves several universities and research centers. Each group is involved in a different area of study to answer specific questions. The hydraulic fracturing computer model has three components---a model for fracture geometry, a model for proppant transport, and a computer program that couples the two models. The fracture geometry model was developed at Oral Roberts University and the proppant transport model wasmore » developed at The University of Tulsa prior to the start of the present work. The present work is directed at enhancing the capabilities of these two models and coupling them to obtain a single model for evaluating the final fracture geometry and proppant distribution within the fracture. The report is organized into four parts. Part 1 describes the fracture geometry modeling effort accomplished at Oral Roberts University, NIPER and recently at The University of Tulsa. The proppant transport model, developed for constant height fractures at the University of Tulsa, is contained in Part 2. The coupling of the Proppant Transport Model and the model for the variable height fracture geometry constitutes Part 3 of this report. Part 4 presents a summary of accomplishments and recommendations of this study. 112 refs., 147 figs., 70 tabs.« less

Photon scattering from a system of multilevel quantum emitters. II. Application to emitters coupled to a one-dimensional waveguide

NASA Astrophysics Data System (ADS)

Das, Sumanta; Elfving, Vincent E.; Reiter, Florentin; Sørensen, Anders S.

2018-04-01

In a preceding paper we introduced a formalism to study the scattering of low-intensity fields from a system of multilevel emitters embedded in a three-dimensional (3 D ) dielectric medium. Here we show how this photon-scattering relation can be used to analyze the scattering of single photons and weak coherent states from any generic multilevel quantum emitter coupled to a one-dimensional (1 D ) waveguide. The reduction of the photon-scattering relation to 1 D waveguides provides a direct solution of the scattering problem involving low-intensity fields in the waveguide QED regime. To show how our formalism works, we consider examples of multilevel emitters and evaluate the transmitted and reflected field amplitude. Furthermore, we extend our study to include the dynamical response of the emitters for scattering of a weak coherent photon pulse. As our photon-scattering relation is based on the Heisenberg picture, it is quite useful for problems involving photodetection in the waveguide architecture. We show this by considering a specific problem of state generation by photodetection in a multilevel emitter, where our formalism exhibits its full potential. Since the considered emitters are generic, the 1 D results apply to a plethora of physical systems such as atoms, ions, quantum dots, superconducting qubits, and nitrogen-vacancy centers coupled to a 1 D waveguide or transmission line.

Iron-Coupled Anaerobic Oxidation of Methane Performed by a Mixed Bacterial-Archaeal Community Based on Poorly Reactive Minerals.

PubMed

Bar-Or, Itay; Elvert, Marcus; Eckert, Werner; Kushmaro, Ariel; Vigderovich, Hanni; Zhu, Qingzeng; Ben-Dov, Eitan; Sivan, Orit

2017-11-07

Anaerobic oxidation of methane (AOM) was shown to reduce methane emissions by over 50% in freshwater systems, its main natural contributor to the atmosphere. In these environments iron oxides can become main agents for AOM, but the underlying mechanism for this process has remained enigmatic. By conducting anoxic slurry incubations with lake sediments amended with 13 C-labeled methane and naturally abundant iron oxides the process was evidenced by significant 13 C-enrichment of the dissolved inorganic carbon pool and most pronounced when poorly reactive iron minerals such as magnetite and hematite were applied. Methane incorporation into biomass was apparent by strong uptake of 13 C into fatty acids indicative of methanotrophic bacteria, associated with increasing copy numbers of the functional methane monooxygenase pmoA gene. Archaea were not directly involved in full methane oxidation, but their crucial participation, likely being mediators in electron transfer, was indicated by specific inhibition of their activity that fully stopped iron-coupled AOM. By contrast, inhibition of sulfur cycling increased 13 C-methane turnover, pointing to sulfur species involvement in a competing process. Our findings suggest that the mechanism of iron-coupled AOM is accomplished by a complex microbe-mineral reaction network, being likely representative of many similar but hidden interactions sustaining life under highly reducing low energy conditions.

Recent Progress in Understanding Subtype Specific Regulation of NMDA Receptors by G Protein Coupled Receptors (GPCRs)

PubMed Central

Yang, Kai; Jackson, Michael F.; MacDonald, John F.

2014-01-01

G Protein Coupled Receptors (GPCRs) are the largest family of receptors whose ligands constitute nearly a third of prescription drugs in the market. They are widely involved in diverse physiological functions including learning and memory. NMDA receptors (NMDARs), which belong to the ionotropic glutamate receptor family, are likewise ubiquitously expressed in the central nervous system (CNS) and play a pivotal role in learning and memory. Despite its critical contribution to physiological and pathophysiological processes, few pharmacological interventions aimed directly at regulating NMDAR function have been developed to date. However, it is well established that NMDAR function is precisely regulated by cellular signalling cascades recruited downstream of G protein coupled receptor (GPCR) stimulation. Accordingly, the downstream regulation of NMDARs likely represents an important determinant of outcome following treatment with neuropsychiatric agents that target selected GPCRs. Importantly, the functional consequence of such regulation on NMDAR function varies, based not only on the identity of the GPCR, but also on the cell type in which relevant receptors are expressed. Indeed, the mechanisms responsible for regulating NMDARs by GPCRs involve numerous intracellular signalling molecules and regulatory proteins that vary from one cell type to another. In the present article, we highlight recent findings from studies that have uncovered novel mechanisms by which selected GPCRs regulate NMDAR function and consequently NMDAR-dependent plasticity. PMID:24562329

Direct observation of methyl rotor and vib-rotor states of S0 toluene: a revised torsional barrier due to torsion-vibration coupling.

PubMed

Gascooke, Jason R; Virgo, Edwina A; Lawrance, Warren D

2015-01-14

We report a two dimensional, laser induced fluorescence study of the lowest 345 cm(-1) region of S0 toluene. Methyl rotor levels of 00 up to m = 6 and of 201 up to m = 4 are observed. The rotor levels of 00 and 201 have quite different energy spacings that are well fit by a model that includes strong torsion-vibration coupling between them. The model requires that the rotor barrier height be revised from -4.84 cm(-1) (methyl hydrogens in a staggered conformation) to +1.57 cm(-1) (eclipsed conformation). However, the 3a2″ state lies below the 3a1″ state as expected for a staggered conformation due to energy shifts associated with the torsion-vibration coupling. It is shown that the rotor wave-functions exhibit little localization at the torsional energy minima. The variation in the m = 0 wavefunction probability distribution with torsional angle is shown to be very similar for the previously accepted negative V6 value and the torsion-vibration coupling model as this coupling shifts the phase of the wavefunction by 30° compared with its phase for V6 alone. The presence of a strong Δυ = ± 1 torsion-vibration coupling involving the lowest frequency vibrational mode provides a potential pathway for rapid intramolecular vibrational energy redistribution at higher energies.

The Role of Dyadic Coping on the Marital and Emotional Adjustment of Couples With Infertility.

PubMed

Chaves, Catarina; Canavarro, Maria Cristina; Moura-Ramos, Mariana

2018-04-30

Infertility is a challenging experience, affecting individual and couples' adjustment. However, the way the members of the couple support each other may affect the experience of infertility and their adjustment. This study aimed to investigate the role of dyadic coping by oneself and by the partner in the association between the impact of infertility and dyadic and emotional adjustment (anxiety and depression) to infertility. In this cross-sectional study, a total of 134 participants (67 couples with infertility) completed self-report questionnaires assessing infertility-related stress, dyadic coping, dyadic adjustment, and depression and anxiety symptoms. A path analysis examined the direct and indirect effects between the impact of infertility in one's life and dyadic and emotional adjustment. There is an indirect effect of the impact of infertility in one's life on dyadic adjustment through men's perceived dyadic coping efforts employed by the self (dyadic coping by oneself) and women's perceived dyadic coping efforts of the partner (dyadic coping by the partner). Regarding the emotional adjustment of infertile couples, infertility stress impact had an indirect effect only on depressive symptoms through men's dyadic coping by oneself. The results highlight the importance of men's dyadic coping strategies for the marital adjustment of couples as well as for men's emotional adjustment. Findings emphasize the importance of involving men in the fertility treatment process, reinforcing the dyadic nature of infertility processes. © 2018 Family Process Institute.

Acoustic mode coupling induced by shallow water nonlinear internal waves: sensitivity to environmental conditions and space-time scales of internal waves.

PubMed

Colosi, John A

2008-09-01

While many results have been intuited from numerical simulation studies, the precise connections between shallow-water acoustic variability and the space-time scales of nonlinear internal waves (NLIWs) as well as the background environmental conditions have not been clearly established analytically. Two-dimensional coupled mode propagation through NLIWs is examined using a perturbation series solution in which each order n is associated with nth-order multiple scattering. Importantly, the perturbation solution gives resonance conditions that pick out specific NLIW scales that cause coupling, and seabed attenuation is demonstrated to broaden these resonances, fundamentally changing the coupling behavior at low frequency. Sound-speed inhomogeneities caused by internal solitary waves (ISWs) are primarily considered and the dependence of mode coupling on ISW amplitude, range width, depth structure, location relative to the source, and packet characteristics are delineated as a function of acoustic frequency. In addition, it is seen that significant energy transfer to modes with initially low or zero energy involves at least a second order scattering process. Under moderate scattering conditions, comparisons of first order, single scattering theoretical predictions to direct numerical simulation demonstrate the accuracy of the approach for acoustic frequencies upto 400 Hz and for single as well as multiple ISW wave packets.

"More Closeted Than Gayness Itself": The Depiction of Same-Sex Couple Violence in Newspaper Media.

PubMed

Estes, Michelle L; Webber, Gretchen R

2017-10-01

Same-sex intimate partner violence (IPV) lacks mainstream news media coverage. News media report on those stories that are most prominent, and these stories are often shaped and presented within a White, heterosexual, upper-class, male framework. This framework largely ignores or misrepresents those that do not fit these characteristics, resulting in a gap in research and coverage of same-sex IPV. This article explores whether U.S. newspapers cover same-sex IPV, how often, and how same-sex couple violence is portrayed in newspapers when covered. Twenty-five newspaper articles published from 2005 to 2015, 10 years prior to the U.S. Supreme Court decision that legalized same-sex marriage, were located and analyzed. Findings indicate sparse newspaper coverage of IPV in same-sex couples. Ten articles highlight the lack of coverage and knowledge related to same-sex couple IPV. Eighteen articles address same-sex IPV as a social issue and highlight resource concerns, police involvement, and heteronormativity and heterosexism. Sixteen articles depict specific instances of IPV in same-sex couples. The overall lack of coverage and how same-sex IPV is covered remains problematic and limited. More mainstream and accurate coverage is needed to effectively address this social issue. Limitations and directions for future research are also discussed.

Direct optical measurement of light coupling into planar waveguide by plasmonic nanoparticles.

PubMed

Pennanen, Antti M; Toppari, J Jussi

2013-01-14

Coupling of light into a thin layer of high refractive index material by plasmonic nanoparticles has been widely studied for application in photovoltaic devices, such as thin-film solar cells. In numerous studies this coupling has been investigated through measurement of e.g. quantum efficiency or photocurrent enhancement. Here we present a direct optical measurement of light coupling into a waveguide by plasmonic nanoparticles. We investigate the coupling efficiency into the guided modes within the waveguide by illuminating the surface of a sample, consisting of a glass slide coated with a high refractive index planar waveguide and plasmonic nanoparticles, while directly measuring the intensity of the light emitted out of the waveguide edge. These experiments were complemented by transmittance and reflectance measurements. We show that the light coupling is strongly affected by thin-film interference, localized surface plasmon resonances of the nanoparticles and the illumination direction (front or rear).

Mesure des couplages trilineaires anomaux des bosons de jauge avec le detecteur OPAL au LEP

NASA Astrophysics Data System (ADS)

Trigger, Isabel Marian

Since 1996, the Large Electron-Positron collider (LEP) at CERN has run at energies sufficiently high for the pair production of electroweak gauge bosons. This permits stringent new tests of the Standard Model of particle physics, which makes very precise predictions of the force and nature of the couplings between these bosons. Two of the possible production processes for W+W- pairs are e+e - --> Z0/γ --> W+W -, which involve W+W-Z 0 and W+W-γ couplings. A detailed study of W+W- events can be used to verify the non-Abelian nature of electroweak interactions, and also, eventually, to probe for phenomena arising from physics beyond the Standard Model. The existence of certain new heavy particles, for example, might result in anomalous couplings. We measure the W+W-Z0 and W+W-γ couplings directly, from the rate of W+W- production in the OPAL detector and from characteristics of the decay product distributions of these events. There are three possible final states for W+W - decays: (i) two oppositely charged leptons and missing energy (W+W- --> l - n l+ n ); (ii)one charged lepton, two jets and missing energy (W+W- --> qq¯l n ); or (iii)four hadronic jets (W+W - --> qq¯qq¯). This thesis principally describes the four-jet decays. This is a complicated final state to reconstruct, as the kinematics of the event must be used to determine which of three possible jet pairings corresponds to the true W+ and W- , and in order to increase the sensitivity to anomalous couplings, it is also necessary to use the charges and momenta of the hadrons in the jets to reconstruct the charge of each W. The angular distributions of the W+/- and of their decay products are directly related to the helicities of the Ws, and provide an insight into the nature of the gauge boson couplings.

Self-assembly of multiferroic core-shell particulate nanocomposites through DNA-DNA hybridization and magnetic field directed assembly of superstructures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sreenivasulu, Gollapudi; Srinivasan, Gopalan, E-mail: srinivas@oakland.edu, E-mail: chavez@oakland.edu; Lochbiler, Thomas A.

Multiferroic composites of ferromagnetic and ferroelectric phases are of importance for studies on mechanical strain mediated coupling between the magnetic and electric subsystems. This work is on DNA-assisted self-assembly of superstructures of such composites with nanometer periodicity. The synthesis involved oligomeric DNA-functionalized ferroelectric and ferromagnetic nanoparticles, 600 nm BaTiO{sub 3} (BTO) and 200 nm NiFe{sub 2}O{sub 4} (NFO), respectively. Mixing BTO and NFO particles, possessing complementary DNA sequences, resulted in the formation of ordered core-shell heteronanocomposites held together by DNA hybridization. The composites were imaged by scanning electron microscopy and scanning microwave microscopy. The presence of heteroassemblies along with core-shellmore » architecture is clearly observed. The reversible nature of the DNA hybridization allows for restructuring the composites into mm-long linear chains and 2D-arrays in the presence of a static magnetic field and ring-like structures in a rotating-magnetic field. Strong magneto-electric (ME) coupling in as-assembled composites is evident from static magnetic field H induced polarization and low-frequency magnetoelectric voltage coefficient measurements. Upon annealing the nanocomposites at high temperatures, evidence for the formation of bulk composites with excellent cross-coupling between the electric and magnetic subsystems is obtained by H-induced polarization and low-frequency ME voltage coefficient. The ME coupling strength in the self-assembled composites is measured to be much stronger than in bulk composites with randomly distributed NFO and BTO prepared by direct mixing and sintering.« less

Electron spin relaxation in a transition-metal dichalcogenide quantum dot

NASA Astrophysics Data System (ADS)

Pearce, Alexander J.; Burkard, Guido

2017-06-01

We study the relaxation of a single electron spin in a circular quantum dot in a transition-metal dichalcogenide monolayer defined by electrostatic gating. Transition-metal dichalcogenides provide an interesting and promising arena for quantum dot nano-structures due to the combination of a band gap, spin-valley physics and strong spin-orbit coupling. First we will discuss which bound state solutions in different B-field regimes can be used as the basis for qubits states. We find that at low B-fields combined spin-valley Kramers qubits to be suitable, while at large magnetic fields pure spin or valley qubits can be envisioned. Then we present a discussion of the relaxation of a single electron spin mediated by electron-phonon interaction via various different relaxation channels. In the low B-field regime we consider the spin-valley Kramers qubits and include impurity mediated valley mixing which will arise in disordered quantum dots. Rashba spin-orbit admixture mechanisms allow for relaxation by in-plane phonons either via the deformation potential or by piezoelectric coupling, additionally direct spin-phonon mechanisms involving out-of-plane phonons give rise to relaxation. We find that the relaxation rates scale as \\propto B 6 for both in-plane phonons coupling via deformation potential and the piezoelectric effect, while relaxation due to the direct spin-phonon coupling scales independant to B-field to lowest order but depends strongly on device mechanical tension. We will also discuss the relaxation mechanisms for pure spin or valley qubits formed in the large B-field regime.

Round window stimulation with the Vibrant Soundbridge: Comparison of direct and indirect coupling.

PubMed

Olszewski, Lukasz; Jedrzejczak, W Wiktor; Piotrowska, Anna; Skarzynski, Henryk

2017-12-01

The purpose of this study was to measure the degree of coupling between the floating mass transducer (FMT) and the round window membrane (RWM) in patients with conductive and mixed hearing loss implanted with the Vibrant Soundbridge (VSB) device. The efficiency of direct and indirect coupling of the FMT to the RWM was compared by measuring differences between the initial prescription targets and the final settings of the VSB audio processor after fine-tuning. Retrospective study. Investigation of a group of subjects with either conductive or mixed hearing loss implanted with the VSB, a device that uses a FMT coupled to the RWM. There were two subgroups: subjects in which coupling was direct (no interposed material) or indirect (interposed material). The functional gain, insertion gain, and compression characteristics of the device were measured to assess the efficiency of coupling and to investigate the proximity of the fitting to prescriptive targets. Coupling for the subgroup with indirect coupling of the RWM was higher (better) than for the subgroup with direct coupling. The gain deviation from prescriptive targets was smaller for the subgroup with indirect coupling. The coupling method can have an effect on the coupling efficiency and the final electroacoustic settings of the device. The prescription targets were not accurate for the majority of subjects from either subgroup. Indirect coupling appears to provide more effective stimulation of the cochlea. 4. Laryngoscope, 127:2843-2849, 2017. © 2017 The American Laryngological, Rhinological and Otological Society, Inc.

National direct-drive program on OMEGA and the National Ignition Facility

NASA Astrophysics Data System (ADS)

Goncharov, V. N.; Regan, S. P.; Campbell, E. M.; Sangster, T. C.; Radha, P. B.; Myatt, J. F.; Froula, D. H.; Betti, R.; Boehly, T. R.; Delettrez, J. A.; Edgell, D. H.; Epstein, R.; Forrest, C. J.; Glebov, V. Yu; Harding, D. R.; Hu, S. X.; Igumenshchev, I. V.; Marshall, F. J.; McCrory, R. L.; Michel, D. T.; Seka, W.; Shvydky, A.; Stoeckl, C.; Theobald, W.; Gatu-Johnson, M.

2017-01-01

A major advantage of the laser direct-drive (DD) approach to ignition is the increased fraction of laser drive energy coupled to the hot spot and relaxed hot-spot requirements for the peak pressure and convergence ratios relative to the indirect-drive approach at equivalent laser energy. With the goal of a successful ignition demonstration using DD, the recently established national strategy has several elements and involves multiple national and international institutions. These elements include the experimental demonstration on OMEGA cryogenic implosions of hot-spot conditions relevant for ignition at MJ-scale energies available at the National Ignition Facility (NIF) and developing an understanding of laser-plasma interactions and laser coupling using DD experiments on the NIF. DD designs require reaching central stagnation pressures in excess of 100 Gbar. The current experiments on OMEGA have achieved inferred peak pressures of 56 Gbar (Regan et al 2016 Phys. Rev. Lett. 117 025001). Extensive analysis of the cryogenic target experiments and two- and three-dimensional simulations suggest that power balance, target offset, and target quality are the main limiting factors in target performance. In addition, cross-beam energy transfer (CBET) has been identified as the main mechanism reducing laser coupling. Reaching the goal of demonstrating hydrodynamic equivalence on OMEGA includes improving laser power balance, target position, and target quality at shot time. CBET must also be significantly reduced and several strategies have been identified to address this issue.

Direct Structural Identification of Gas Induced Gate-Opening Coupled with Commensurate Adsorption in a Microporous Metal-Organic Framework.

PubMed

Banerjee, Debasis; Wang, Hao; Plonka, Anna M; Emge, Thomas J; Parise, John B; Li, Jing

2016-08-08

Gate-opening is a unique and interesting phenomenon commonly observed in flexible porous frameworks, where the pore characteristics and/or crystal structures change in response to external stimuli such as adding or removing guest molecules. For gate-opening that is induced by gas adsorption, the pore-opening pressure often varies for different adsorbate molecules and, thus, can be applied to selectively separate a gas mixture. The detailed understanding of this phenomenon is of fundamental importance to the design of industrially applicable gas-selective sorbents, which remains under investigated due to the lack of direct structural evidence for such systems. We report a mechanistic study of gas-induced gate-opening process of a microporous metal-organic framework, [Mn(ina)2 ] (ina=isonicotinate) associated with commensurate adsorption, by a combination of several analytical techniques including single crystal X-ray diffraction, in situ powder X-ray diffraction coupled with differential scanning calorimetry (XRD-DSC), and gas adsorption-desorption methods. Our study reveals that the pronounced and reversible gate opening/closing phenomena observed in [Mn(ina)2 ] are coupled with a structural transition that involves rotation of the organic linker molecules as a result of interaction of the framework with adsorbed gas molecules including carbon dioxide and propane. The onset pressure to open the gate correlates with the extent of such interaction. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Mothers' and Fathers' Couple and Family Contextual Influences, Parent Involvement, and School-Age Child Attachment

ERIC Educational Resources Information Center

Coyl-Shepherd, Diana D.; Newland, Lisa A.

2013-01-01

Increasingly couples in two-parent families share the dual responsibilities of parenting and providing for their children financially. Parenting is embedded within and shaped by specific family contexts. This study examined 92 mothers' and fathers' responses on indices of couple and family contexts, parent involvement, and child-reported…

A loop-gap resonator for chirality-sensitive nuclear magneto-electric resonance (NMER)

NASA Astrophysics Data System (ADS)

Garbacz, Piotr; Fischer, Peer; Krämer, Steffen

2016-09-01

Direct detection of molecular chirality is practically impossible by methods of standard nuclear magnetic resonance (NMR) that is based on interactions involving magnetic-dipole and magnetic-field operators. However, theoretical studies provide a possible direct probe of chirality by exploiting an enantiomer selective additional coupling involving magnetic-dipole, magnetic-field, and electric field operators. This offers a way for direct experimental detection of chirality by nuclear magneto-electric resonance (NMER). This method uses both resonant magnetic and electric radiofrequency (RF) fields. The weakness of the chiral interaction though requires a large electric RF field and a small transverse RF magnetic field over the sample volume, which is a non-trivial constraint. In this study, we present a detailed study of the NMER concept and a possible experimental realization based on a loop-gap resonator. For this original device, the basic principle and numerical studies as well as fabrication and measurements of the frequency dependence of the scattering parameter are reported. By simulating the NMER spin dynamics for our device and taking the 19F NMER signal of enantiomer-pure 1,1,1-trifluoropropan-2-ol, we predict a chirality induced NMER signal that accounts for 1%-5% of the standard achiral NMR signal.

Radiation characteristics of Leaky Surface Plasmon polaritons of graphene

NASA Astrophysics Data System (ADS)

Mohadesi, V.; Asgari, A.; Siahpoush, V.

2018-07-01

High efficient coupling of graphene surface plasmons to far field radiation is possible by some techniques and can be used in the radiating applications. Besides of the coupling efficiency, the angular distribution of the radiated power is an important parameter in the radiating devices performance. In this paper we investigate the gain of the far field radiation related to the coupling of graphene surface plasmons via a high permittivity medium located close to the graphene. Our results show that high directive radiation and high coupling efficiency can be obtained by this technique and gain and directivity of radiation can be modified by graphene characteristics such as chemical potential and also quality of the graphene. Raising the chemical potential of graphene leads to increase the gain of the radiation as the result of amplifying the directivity of the radiation. Furthermore, high values of relaxation time lead to high directive and strong coupling which raises the maximum value of gain in efficient coupling angle. Tunable characteristics of gain and directivity in this structure can be important designing reconfigurable THz radiating devices.

Large eddy simulations and direct numerical simulations of high speed turbulent reacting flows

NASA Technical Reports Server (NTRS)

Givi, Peyman; Madnia, C. K.; Steinberger, C. J.; Tsai, A.

1991-01-01

This research is involved with the implementations of advanced computational schemes based on large eddy simulations (LES) and direct numerical simulations (DNS) to study the phenomenon of mixing and its coupling with chemical reactions in compressible turbulent flows. In the efforts related to LES, a research program was initiated to extend the present capabilities of this method for the treatment of chemically reacting flows, whereas in the DNS efforts, focus was on detailed investigations of the effects of compressibility, heat release, and nonequilibrium kinetics modeling in high speed reacting flows. The efforts to date were primarily focussed on simulations of simple flows, namely, homogeneous compressible flows and temporally developing hign speed mixing layers. A summary of the accomplishments is provided.

Measurement of sin 2 θ ℓ eff and Z-light quark couplings using the forward-backward charge asymmetry in pp -> Z/gamma * -> e +e - events with L=5.0 fb -1 at √s=1.96 TeV

DOE PAGES

Abazov, V. M.

2011-07-26

We measure the mass dependence of the forward-backward charge asymmetry in 157,553 pp = Z/γ* = e +e - interactions, corresponding to 5.0 fb -1 of integrated luminosity collected by the D0 experiment at the Fermilab Tevatron Collider at √s = 1.96 TeV. The effective weak mixing angle (θ ℓ eff) from this process involving predominantly the first generation of quarks is extracted as sin 2 θ ℓ eff = 0.2309 ± 0.0008 (stat.) ± 0.0006 (syst.). We also present the most precise direct measurement of the vector and axial-vector couplings of u and d quarks to the Z boson.

Microscopic Lagrangian description of warm plasmas. I - Linear wave propagation. II - Nonlinear wave interactions

NASA Technical Reports Server (NTRS)

Kim, H.; Crawford, F. W.

1977-01-01

It is pointed out that the conventional iterative analysis of nonlinear plasma wave phenomena, which involves a direct use of Maxwell's equations and the equations describing the particle dynamics, leads to formidable theoretical and algebraic complexities, especially for warm plasmas. As an effective alternative, the Lagrangian method may be applied. It is shown how this method may be used in the microscopic description of small-signal wave propagation and in the study of nonlinear wave interactions. The linear theory is developed for an infinite, homogeneous, collisionless, warm magnetoplasma. A summary is presented of a perturbation expansion scheme described by Galloway and Kim (1971), and Lagrangians to third order in perturbation are considered. Attention is given to the averaged-Lagrangian density, the action-transfer and coupled-mode equations, and the general solution of the coupled-mode equations.

Direction of coupling from phases of interacting oscillators: An information-theoretic approach

NASA Astrophysics Data System (ADS)

Paluš, Milan; Stefanovska, Aneta

2003-05-01

A directionality index based on conditional mutual information is proposed for application to the instantaneous phases of weakly coupled oscillators. Its abilities to distinguish unidirectional from bidirectional coupling, as well as to reveal and quantify asymmetry in bidirectional coupling, are demonstrated using numerical examples of quasiperiodic, chaotic, and noisy oscillators, as well as real human cardiorespiratory data.

A Lever Coupling Mechanism in Dual-Mass Micro-Gyroscopes for Improving the Shock Resistance along the Driving Direction.

PubMed

Gao, Yang; Li, Hongsheng; Huang, Libin; Sun, Hui

2017-04-30

This paper presents the design and application of a lever coupling mechanism to improve the shock resistance of a dual-mass silicon micro-gyroscope with drive mode coupled along the driving direction without sacrificing the mechanical sensitivity. Firstly, the mechanical sensitivity and the shock response of the micro-gyroscope are theoretically analyzed. In the mechanical design, a novel lever coupling mechanism is proposed to change the modal order and to improve the frequency separation. The micro-gyroscope with the lever coupling mechanism optimizes the drive mode order, increasing the in-phase mode frequency to be much larger than the anti-phase one. Shock analysis results show that the micro-gyroscope structure with the designed lever coupling mechanism can notably reduce the magnitudes of the shock response and cut down the stress produced in the shock process compared with the traditional elastic coupled one. Simulations reveal that the shock resistance along the drive direction is greatly increased. Consequently, the lever coupling mechanism can change the gyroscope's modal order and improve the frequency separation by structurally offering a higher stiffness difference ratio. The shock resistance along the driving direction is tremendously enhanced without loss of the mechanical sensitivity.

Longitudinal spin dynamics in nickel fluorosilicate

NASA Astrophysics Data System (ADS)

Galkina, E. G.; Ivanov, B. A.; Butrim, V. I.

2014-07-01

The presence of single-ion anisotropy leads to the appearance of the effect of quantum spin reduction. As a consequence, purely longitudinal magnetization dynamics arises, which involves coupled oscillations of the mean spin modulus and the quadrupole mean values constructed on spin operators. In nickel fluorosilicate, the effect of quantum spin reduction may be controlled by changing pressure. The study of nonlinear longitudinal spin dynamics and the analysis of possible photomagnetic effects showed that this compound is a convenient model system to implement switching of the magnetization direction by femtosecond laser pulses.

Tropospheric Diagnostic Modeling Studies of PEM-Tropics B Field Data: Investigation of the HOx/NOx/O3 Photochemical System and its Coupling to Sulfur Chemistry

NASA Technical Reports Server (NTRS)

Davis, Douglas D.

2001-01-01

Over the time period of this NASA grant the PI has helped plan and execute the PEM-Tropics B field program. He has also helped organize and co-chair two data workshops which have focused on the detailed analysis of PEM-Tropics B data. His direct participation in these analyses has led to his involvement in 13 manuscripts, nine of which are in print, two in press, and two submitted. A complete list of papers is given.

Direct diode lasers with comparable beam quality to fiber, CO2, and solid state lasers

NASA Astrophysics Data System (ADS)

Huang, Robin K.; Chann, Bien; Burgess, James; Kaiman, Michael; Overman, Robert; Glenn, John D.; Tayebati, Parviz

2012-03-01

TeraDiode has produced kW-class ultra-high brightness fiber-coupled direct diode lasers. A fiber-coupled direct diode laser with a power level of 2,040 W from a 50 μm core diameter, 0.15 numerical aperture (NA) output fiber at a single center wavelength was demonstrated. This was achieved with a novel beam combining and shaping technique using COTS diode lasers. The fiber-coupled output corresponds to a Beam Parameter Product (BPP) of 3.75 mm-mrad and is the lowest BPP kW-class direct diode laser yet reported. This laser is suitable for industrial materials processing applications, including sheet metal cutting and welding. This 2-kW fiber-coupled direct diode laser has comparable brightness to that of industrial fiber lasers and CO2 lasers, and is over 10x brighter than state-of-the-art direct diode lasers.

Directional amplifier in an optomechanical system with optical gain

NASA Astrophysics Data System (ADS)

Jiang, Cheng; Song, L. N.; Li, Yong

2018-05-01

Directional amplifiers are crucial nonreciprocal devices in both classical and quantum information processing. Here we propose a scheme for realizing a directional amplifier between optical and microwave fields based on an optomechanical system with optical gain, where an active optical cavity and two passive microwave cavities are coupled to a common mechanical resonator via radiation pressure. The two passive cavities are coupled via hopping interaction to facilitate the directional amplification between the active and passive cavities. We obtain the condition of achieving optical directional amplification and find that the direction of amplification can be controlled by the phase differences between the effective optomechanical couplings. The effects of the gain rate of the active cavity and the effective coupling strengths on the maximum gain of the amplifier are discussed. We show that the noise added to this amplifier can be greatly suppressed in the large cooperativity limit.

G-protein-coupled receptor-2-interacting protein-1 is required for endothelial cell directional migration and tumor angiogenesis via cortactin-dependent lamellipodia formation.

PubMed

Majumder, Syamantak; Sowden, Mark P; Gerber, Scott A; Thomas, Tamlyn; Christie, Christine K; Mohan, Amy; Yin, Guoyong; Lord, Edith M; Berk, Bradford C; Pang, Jinjiang

2014-02-01

Recent evidence suggests G-protein-coupled receptor-2-interacting protein-1 (GIT1) overexpression in several human metastatic tumors, including breast, lung, and prostate. Tumor metastasis is associated with an increase in angiogenesis. We have showed previously that GIT1 is required for postnatal angiogenesis during lung development. However, the functional role of GIT1 in pathological angiogenesis during tumor growth is unknown. In the present study, we show inhibition of angiogenesis in matrigel implants as well as reduced tumor angiogenesis and melanoma tumor growth in GIT1-knockout mice. We demonstrate that this is a result of impaired directional migration of GIT1-depleted endothelial cells toward a vascular endothelial growth factor gradient. Cortactin-mediated lamellipodia formation in the leading edge is critical for directional migration. We observed a significant reduction in cortactin localization and lamellipodia formation in the leading edge of GIT1-depleted endothelial cells. We specifically identified that the Spa homology domain (aa 250-420) of GIT1 is required for GIT1-cortactin complex localization to the leading edge. The mechanisms involved extracellular signal-regulated kinases 1 and 2-mediated Cortactin-S405 phosphorylation and activation of Rac1/Cdc42. Finally, using gain of function studies, we show that a constitutively active mutant of cortactin restored directional migration of GIT1-depleted cells. Our data demonstrated that a GIT1-cortactin association through GIT1-Spa homology domain is required for cortactin localization to the leading edge and is essential for endothelial cell directional migration and tumor angiogenesis.

Dynamic acousto-optic control of a strongly coupled photonic molecule

PubMed Central

Kapfinger, Stephan; Reichert, Thorsten; Lichtmannecker, Stefan; Müller, Kai; Finley, Jonathan J.; Wixforth, Achim; Kaniber, Michael; Krenner, Hubert J.

2015-01-01

Strongly confined photonic modes can couple to quantum emitters and mechanical excitations. To harness the full potential in quantum photonic circuits, interactions between different constituents have to be precisely and dynamically controlled. Here, a prototypical coupled element, a photonic molecule defined in a photonic crystal membrane, is controlled by a radio frequency surface acoustic wave. The sound wave is tailored to deliberately switch on and off the bond of the photonic molecule on sub-nanosecond timescales. In time-resolved experiments, the acousto-optically controllable coupling is directly observed as clear anticrossings between the two nanophotonic modes. The coupling strength is determined directly from the experimental data. Both the time dependence of the tuning and the inter-cavity coupling strength are found to be in excellent agreement with numerical calculations. The demonstrated mechanical technique can be directly applied for dynamic quantum gate operations in state-of-the-art-coupled nanophotonic, quantum cavity electrodynamic and optomechanical systems. PMID:26436203

NACE-ESI-TOF MS to reveal phenolic compounds from olive oil: introducing enriched olive oil directly inside capillary.

PubMed

Gómez-Caravaca, Ana María; Carrasco-Pancorbo, Alegría; Segura-Carretero, Antonio; Fernández-Gutiérrez, Alberto

2009-09-01

Most CE methods for the analysis of phenols from olive oil use an aqueous electrolyte separation medium, although the importance of NACE is obvious, as this kind of CE seems to be more compatible with the hydrophobic olive oil matrix and could facilitate its direct injection. In the current work we develop a method involving SPE and NACE coupled to ESI-TOF MS. All the CE and ESI-TOF MS parameters were optimized in order to maximize the number of phenolic compounds detected and the sensitivity in their determination. Electrophoretic separation was carried out using a CE buffer system consisting of 25 mM NH(4)OAc/AcH in methanol/ACN (1/1 v/v) at an apparent pH value of 5.0. We studied in depth the effect of the nature and concentration of different electrolytes dissolved in different organic solvents and other experimental and instrumental CE variables. The results were compared with those obtained by CZE (with aqueous buffers) coupled to ESI-TOF MS; both methods offered to the analyst the chance to study phenolic compounds of different families (such as phenolic alcohols, lignans, complex phenols, flavonoids, etc.) from virgin olive oil by injecting methanolic extracts with efficient and fast CE separations. In the case of NACE method, we also studied the direct injection of the investigated matrix introducing a plug of olive oil directly into the capillary.

The impact of blended teaching on knowledge, satisfaction, and self-directed learning in nursing undergraduates: a randomized, controlled trial.

PubMed

Gagnon, Marie-Pierre; Gagnon, Johanne; Desmartis, Marie; Njoya, Merlin

2013-01-01

This study aimed to assess the effectiveness of a blended-teaching intervention using Internet-based tutorials coupled with traditional lectures in an introduction to research undergraduate nursing course. Effects of the intervention were compared with conventional, face-to-face classroom teaching on three outcomes: knowledge, satisfaction, and self-learning readiness. A two-group, randomized, controlled design was used, involving 112 participants. Descriptive statistics and analysis of covariance (ANCOVA) were performed. The teaching method was found to have no direct impact on knowledge acquisition, satisfaction, and self-learning readiness. However, motivation and teaching method had an interaction effect on knowledge acquisition by students. Among less motivated students, those in the intervention group performed better than those who received traditional training. These findings suggest that this blended-teaching method could better suit some students, depending on their degree of motivation and level of self-directed learning readiness.

Formation control of VTOL UAV vehicles under switching-directed interaction topologies with disturbance rejection

NASA Astrophysics Data System (ADS)

Kabiri, Meisam; Atrianfar, Hajar; Menhaj, Mohammad B.

2018-01-01

This paper addresses the adaptive formation control of a group of vertical take-off and landing (VTOL) unmanned aerial vehicles (UAV) with switching-directed interaction topologies. In addition, to tackle the adverse effect of disturbances, a couple of smooth bounded estimators are involved in the procedure design. Exploiting an extraction algorithm, we take advantage of the fully actuated rotational dynamics, to control the translational dynamics of each vehicle. We propose a distributed control scheme such that all vehicles track a desired reference velocity signal while keeping a desired prespecified formation. In this framework, the underlying topology of the agents may switch among several directed graphs, each having a spanning tree. The stability of the overall closed-loop system is proved through Lyapunov function. Finally, simulation results are given to better highlight the effectiveness of the proposed control scheme.

Depth-variant azimuthal anisotropy in Tibet revealed by surface wave tomography

NASA Astrophysics Data System (ADS)

Pandey, Shantanu; Yuan, Xiaohui; Debayle, Eric; Tilmann, Frederik; Priestley, Keith; Li, Xueqing

2015-06-01

Azimuthal anisotropy derived from multimode Rayleigh wave tomography in China exhibits depth-dependent variations in Tibet, which can be explained as induced by the Cenozoic India-Eurasian collision. In west Tibet, the E-W fast polarization direction at depths <100 km is consistent with the accumulated shear strain in the Tibetan lithosphere, whereas the N-S fast direction at greater depths is aligned with Indian Plate motion. In northeast Tibet, depth-consistent NW-SE directions imply coupled deformation throughout the whole lithosphere, possibly also involving the underlying asthenosphere. Significant anisotropy at depths of 225 km in southeast Tibet reflects sublithospheric deformation induced by northward and eastward lithospheric subduction beneath the Himalaya and Burma, respectively. The multilayer anisotropic surface wave model can explain some features of SKS splitting measurements in Tibet, with differences probably attributable to the limited back azimuthal coverage of most SKS studies in Tibet and the limited horizontal resolution of the surface wave results.

Coparenting and Father Involvement in Married and Unmarried Coresident Couples

ERIC Educational Resources Information Center

Hohmann-Marriott, Bryndl

2011-01-01

Children can benefit from involved fathers and cooperative parents, a benefit which may be particularly important to the growing population of children born to unmarried parents. This study observes father involvement and coparenting in 5,407 married and unmarried cohabiting couples with a 2-year-old child in the Early Childhood Longitudinal…

20 CFR 416.435 - Change in status involving a couple; ineligibility occurs.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 20 Employees' Benefits 2 2013-04-01 2013-04-01 false Change in status involving a couple; ineligibility occurs. 416.435 Section 416.435 Employees' Benefits SOCIAL SECURITY ADMINISTRATION SUPPLEMENTAL SECURITY INCOME FOR THE AGED, BLIND, AND DISABLED Amount of Benefits § 416.435 Change in status involving a...

20 CFR 416.432 - Change in status involving a couple; eligibility continues.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 20 Employees' Benefits 2 2011-04-01 2011-04-01 false Change in status involving a couple; eligibility continues. 416.432 Section 416.432 Employees' Benefits SOCIAL SECURITY ADMINISTRATION SUPPLEMENTAL SECURITY INCOME FOR THE AGED, BLIND, AND DISABLED Amount of Benefits § 416.432 Change in status involving a...

20 CFR 416.435 - Change in status involving a couple; ineligibility occurs.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 20 Employees' Benefits 2 2011-04-01 2011-04-01 false Change in status involving a couple; ineligibility occurs. 416.435 Section 416.435 Employees' Benefits SOCIAL SECURITY ADMINISTRATION SUPPLEMENTAL SECURITY INCOME FOR THE AGED, BLIND, AND DISABLED Amount of Benefits § 416.435 Change in status involving a...

20 CFR 416.432 - Change in status involving a couple; eligibility continues.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 20 Employees' Benefits 2 2013-04-01 2013-04-01 false Change in status involving a couple; eligibility continues. 416.432 Section 416.432 Employees' Benefits SOCIAL SECURITY ADMINISTRATION SUPPLEMENTAL SECURITY INCOME FOR THE AGED, BLIND, AND DISABLED Amount of Benefits § 416.432 Change in status involving a...

20 CFR 416.435 - Change in status involving a couple; ineligibility occurs.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 20 Employees' Benefits 2 2010-04-01 2010-04-01 false Change in status involving a couple; ineligibility occurs. 416.435 Section 416.435 Employees' Benefits SOCIAL SECURITY ADMINISTRATION SUPPLEMENTAL SECURITY INCOME FOR THE AGED, BLIND, AND DISABLED Amount of Benefits § 416.435 Change in status involving a...

20 CFR 416.432 - Change in status involving a couple; eligibility continues.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 20 Employees' Benefits 2 2010-04-01 2010-04-01 false Change in status involving a couple; eligibility continues. 416.432 Section 416.432 Employees' Benefits SOCIAL SECURITY ADMINISTRATION SUPPLEMENTAL SECURITY INCOME FOR THE AGED, BLIND, AND DISABLED Amount of Benefits § 416.432 Change in status involving a...

20 CFR 416.435 - Change in status involving a couple; ineligibility occurs.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 20 Employees' Benefits 2 2012-04-01 2012-04-01 false Change in status involving a couple; ineligibility occurs. 416.435 Section 416.435 Employees' Benefits SOCIAL SECURITY ADMINISTRATION SUPPLEMENTAL SECURITY INCOME FOR THE AGED, BLIND, AND DISABLED Amount of Benefits § 416.435 Change in status involving a...

Colorless top partners, a 125 GeV Higgs boson, and the limits on naturalness

DOE Office of Scientific and Technical Information (OSTI.GOV)

Burdman, Gustavo; Chacko, Zackaria; Harnik, Roni

2015-03-09

Theories of physics beyond the Standard Model that address the hierarchy problem generally involve top partners, new particles that cancel the quadratic divergences associated with the Yukawa coupling of the Higgs to the top quark. With extensions of the Standard Model that involve new colored particles coming under strain from collider searches, scenarios in which the top partners carry no charge under the strong interactions have become increasingly compelling. Although elusive for direct searches, these theories predict modified couplings of the Higgs boson to the Standard Model particles. This results in corrections to the Higgs production and decay rates that can be detected at the Large Hadron Collider (LHC) provided the top partners are sufficiently light, and the theory correspondingly natural. In this paper we consider three theories that address the little hierarchy problem and involve colorless top partners, specifically the Mirror Twin Higgs, Folded Supersymmetry, and the Quirky Little Higgs. For each model we investigate the current and future bounds on the top partners, and the corresponding limits on naturalness, that can be obtained from the Higgs program at the LHC. Here, we conclude that the LHC will not be able to strongly disfavor naturalness, with mild tuning at the level of about one part in ten remaining allowed even with 3000 fbmore » $$^{-1}$$ of data at 14 TeV.« less

Catalytic alkylation of remote C-H bonds enabled by proton-coupled electron transfer

NASA Astrophysics Data System (ADS)

Choi, Gilbert J.; Zhu, Qilei; Miller, David C.; Gu, Carol J.; Knowles, Robert R.

2016-11-01

Despite advances in hydrogen atom transfer (HAT) catalysis, there are currently no molecular HAT catalysts that are capable of homolysing the strong nitrogen-hydrogen (N-H) bonds of N-alkyl amides. The motivation to develop amide homolysis protocols stems from the utility of the resultant amidyl radicals, which are involved in various synthetically useful transformations, including olefin amination and directed carbon-hydrogen (C-H) bond functionalization. In the latter process—a subset of the classical Hofmann-Löffler-Freytag reaction—amidyl radicals remove hydrogen atoms from unactivated aliphatic C-H bonds. Although powerful, these transformations typically require oxidative N-prefunctionalization of the amide starting materials to achieve efficient amidyl generation. Moreover, because these N-activating groups are often incorporated into the final products, these methods are generally not amenable to the direct construction of carbon-carbon (C-C) bonds. Here we report an approach that overcomes these limitations by homolysing the N-H bonds of N-alkyl amides via proton-coupled electron transfer. In this protocol, an excited-state iridium photocatalyst and a weak phosphate base cooperatively serve to remove both a proton and an electron from an amide substrate in a concerted elementary step. The resultant amidyl radical intermediates are shown to promote subsequent C-H abstraction and radical alkylation steps. This C-H alkylation represents a catalytic variant of the Hofmann-Löffler-Freytag reaction, using simple, unfunctionalized amides to direct the formation of new C-C bonds. Given the prevalence of amides in pharmaceuticals and natural products, we anticipate that this method will simplify the synthesis and structural elaboration of amine-containing targets. Moreover, this study demonstrates that concerted proton-coupled electron transfer can enable homolytic activation of common organic functional groups that are energetically inaccessible using traditional HAT-based approaches.

Catalytic alkylation of remote C-H bonds enabled by proton-coupled electron transfer.

PubMed

Choi, Gilbert J; Zhu, Qilei; Miller, David C; Gu, Carol J; Knowles, Robert R

2016-11-10

Despite advances in hydrogen atom transfer (HAT) catalysis, there are currently no molecular HAT catalysts that are capable of homolysing the strong nitrogen-hydrogen (N-H) bonds of N-alkyl amides. The motivation to develop amide homolysis protocols stems from the utility of the resultant amidyl radicals, which are involved in various synthetically useful transformations, including olefin amination and directed carbon-hydrogen (C-H) bond functionalization. In the latter process-a subset of the classical Hofmann-Löffler-Freytag reaction-amidyl radicals remove hydrogen atoms from unactivated aliphatic C-H bonds. Although powerful, these transformations typically require oxidative N-prefunctionalization of the amide starting materials to achieve efficient amidyl generation. Moreover, because these N-activating groups are often incorporated into the final products, these methods are generally not amenable to the direct construction of carbon-carbon (C-C) bonds. Here we report an approach that overcomes these limitations by homolysing the N-H bonds of N-alkyl amides via proton-coupled electron transfer. In this protocol, an excited-state iridium photocatalyst and a weak phosphate base cooperatively serve to remove both a proton and an electron from an amide substrate in a concerted elementary step. The resultant amidyl radical intermediates are shown to promote subsequent C-H abstraction and radical alkylation steps. This C-H alkylation represents a catalytic variant of the Hofmann-Löffler-Freytag reaction, using simple, unfunctionalized amides to direct the formation of new C-C bonds. Given the prevalence of amides in pharmaceuticals and natural products, we anticipate that this method will simplify the synthesis and structural elaboration of amine-containing targets. Moreover, this study demonstrates that concerted proton-coupled electron transfer can enable homolytic activation of common organic functional groups that are energetically inaccessible using traditional HAT-based approaches.

A study of the vibrational energies of two coupled beams by finite element and green function (receptance) methods

NASA Astrophysics Data System (ADS)

Shankar, K.; Keane, A. J.

1995-04-01

The behaviour of two hinged-hinged beams, point coupled by springs (translational, rotary and a combination of both) with weak to strong coupling is studied from the point of view of vibrational energies, input power and power transferred through the coupling. Two configurations are studied: in the first case the beams are placed parallel to each other and only the transverse, Euler-Bernoulli modes are considered; the second configuration is more complicated with the beams placed perpendicular to each other, executing axial as well as transverse vibrations. These models are studied by using a finite element analysis (FEA) package and, alternatively, via the modally derived Green functions of the uncoupled subsystems. In both cases the beams are given proportional damping and one of the beams is driven by a point harmonic force. The effects of coupling stiffness and modal summation bandwidth are studied. It is shown that there is good agreement between the FEA and the Green function approach over a range of coupling strengths, but that at higher strengths the number of uncoupled modes used significantly affects the accuracy of the Green function method used here. The beams in the second configuration are then further studied from the point of view of SEA coupling loss factors. The frequency averaged coupling loss factors are calculated for weak and strong coupling, first by using a power injection method, where the power balance equations are formed on the assumption of only direct coupling loss factors. Then, the entire matrix of direct and indirect coupling loss factors is derived by using a deterministic modal approach. These are compared and the indirect coupling loss factors are found to be significant in magnitude in respect to the direct coupling loss factors. Several cases are studied in which the coupling powers and energy levels are predicted by using only the direct coupling loss factors and compared with the exact results obtained by using both direct and indirect factors. These agree only under certain conditions for weak coupling and show rather poorer agreement in the case of strong coupling. This behaviour demonstrates the importance of taking into account indirect coupling loss factors in SEA models having several subsystems.

The α Subunit of the G Protein G13 Regulates Activity of One or More Gli Transcription Factors Independently of Smoothened*

PubMed Central

Douglas, Andrew E.; Heim, Jennifer A.; Shen, Feng; Almada, Luciana L.; Riobo, Natalia A.; Fernández-Zapico, Martin E.; Manning, David R.

2011-01-01

Smoothened (Smo) is a seven-transmembrane (7-TM) receptor that is essential to most actions of the Hedgehog family of morphogens. We found previously that Smo couples to members of the Gi family of heterotrimeric G proteins, which in some cases are integral although alone insufficient in the activation of Gli transcription factors through Hedgehog signaling. In response to a report that the G12/13 family is relevant to Hedgehog signaling as well, we re-evaluated the coupling of Smo to one member of this family, G13, and investigated the capacity of this and other G proteins to activate one or more of forms of Gli. We found no evidence that Smo couples directly to G13. We found nonetheless that Gα13 and to some extent Gαq and Gα12 are able to effect activation of Gli(s). This capacity is realized in some cells, e.g. C3H10T1/2, MC3T3, and pancreatic cancer cells, but not all cells. The mechanism employed is distinct from that achieved through canonical Hedgehog signaling, as the activation does not involve autocrine signaling or in any other way require active Smo and does not necessarily involve enhanced transcription of Gli1. The activation by Gα13 can be replicated through a Gq/G12/13-coupled receptor, CCKA, and is attenuated by inhibitors of p38 mitogen-activated protein kinase and Tec tyrosine kinases. We posit that G proteins, and perhaps G13 in particular, provide access to Gli that is independent of Smo and that they thus establish a basis for control of at least some forms of Gli-mediated transcription apart from Hedgehogs. PMID:21757753

Role of estrogen receptors alpha, beta and GPER1/GPR30 in pancreatic beta-cells.

PubMed

Nadal, Angel; Alonso-Magdalena, Paloma; Soriano, Sergi; Ripoll, Cristina; Fuentes, Esther; Quesada, Ivan; Ropero, Ana Belen

2011-01-01

Estrogen receptors (ER) are emerging as important molecules involved in the adaptation of beta-cells to insulin resistance. The onset of type 2 diabetes is marked by insulin secretory dysfunction and decreased beta-cell mass. During pregnancy, puberty and obesity there is increased metabolic demand and insulin resistance is developed. This metabolic state increases the demand on beta-cells to augment insulin biosynthesis and release. In this respect, ERalpha is directly implicated in the E2-regulation of insulin content and secretion, while ERbeta is in the E2-potentiation of glucose-induced insulin release. Both receptors develop their actions within the physiological range of E2. In addition, the G protein-coupled estrogen receptor (GPER1/GPR30) seems to be implicated in the E2-regulation of stimulus-secretion coupling in the three cell types of the islet. The increased demand of insulin production for long time may lead to beta-cell stress and apoptosis. ERalpha, ERbeta and GPER1/GPR30 are involved in preventing beta-cell apoptosis, impeding the loss of critical beta-cell mass. Therefore, estrogen receptors may play an essential role in the adaptation of the pancreas to insulin resistant periods.

The use of selective adsorbents in capillary electrophoresis-mass spectrometry for analyte preconcentration and microreactions: a powerful three-dimensional tool for multiple chemical and biological applications.

PubMed

Guzman, N A; Stubbs, R J

2001-10-01

Much attention has recently been directed to the development and application of online sample preconcentration and microreactions in capillary electrophoresis using selective adsorbents based on chemical or biological specificity. The basic principle involves two interacting chemical or biological systems with high selectivity and affinity for each other. These molecular interactions in nature usually involve noncovalent and reversible chemical processes. Properly bound to a solid support, an "affinity ligand" can selectively adsorb a "target analyte" found in a simple or complex mixture at a wide range of concentrations. As a result, the isolated analyte is enriched and highly purified. When this affinity technique, allowing noncovalent chemical interactions and biochemical reactions to occur, is coupled on-line to high-resolution capillary electrophoresis and mass spectrometry, a powerful tool of chemical and biological information is created. This paper describes the concept of biological recognition and affinity interaction on-line with high-resolution separation, the fabrication of an "analyte concentrator-microreactor", optimization conditions of adsorption and desorption, the coupling to mass spectrometry, and various applications of clinical and pharmaceutical interest.

Mesh infrastructure for coupled multiprocess geophysical simulations

DOE PAGES

Garimella, Rao V.; Perkins, William A.; Buksas, Mike W.; ...

2014-01-01

We have developed a sophisticated mesh infrastructure capability to support large scale multiphysics simulations such as subsurface flow and reactive contaminant transport at storage sites as well as the analysis of the effects of a warming climate on the terrestrial arctic. These simulations involve a wide range of coupled processes including overland flow, subsurface flow, freezing and thawing of ice rich soil, accumulation, redistribution and melting of snow, biogeochemical processes involving plant matter and finally, microtopography evolution due to melting and degradation of ice wedges below the surface. In addition to supporting the usual topological and geometric queries about themore » mesh, the mesh infrastructure adds capabilities such as identifying columnar structures in the mesh, enabling deforming of the mesh subject to constraints and enabling the simultaneous use of meshes of different dimensionality for subsurface and surface processes. The generic mesh interface is capable of using three different open source mesh frameworks (MSTK, MOAB and STKmesh) under the hood allowing the developers to directly compare them and choose one that is best suited for the application's needs. We demonstrate the results of some simulations using these capabilities as well as present a comparison of the performance of the different mesh frameworks.« less

Analysis of protein prenylation and S-acylation using gas chromatography-coupled mass spectrometry.

PubMed

Sorek, Nadav; Akerman, Amir; Yalovsky, Shaul

2013-01-01

Lipid modifications play a key role in protein targeting and function. The two Arabidopsis Gγ subunits, AGG1 and AGG2, have been shown to undergo prenylation (AGG1) and S-acylation (AGG2). Prenylation involves covalent nonreversible attachment of either farnesyl (15 carbons) or geranylgeranyl (20 carbons) isoprenoids to conserved cysteine residues at or near the C-terminus of proteins. S-acylation, frequently referred to as palmitoylation, involves the attachment of acyl fatty acids to thiol groups of cysteine residues through a reversible thioester bond. The procedures described below allow direct analysis of the prenyl and acyl moieties using gas chromatography-coupled mass spectrometry (GC-MS). These methods are based on (1) cleavage of prenyl groups with the Raney nickel catalyst and (2) analysis of protein S-acylation following cleavage of the acyl fatty acids from proteins by hydrogenation with platinum (IV) oxide. The hydrogenation under these conditions causes an acid transesterification of the acyl moieties, adding an ethyl group to the carboxyl head of the fatty acid. The addition of the ethyl group reduces the polarity of the fatty acids, allowing their efficient separation by gas chromatography.

Double-temperature ratchet model and current reversal of coupled Brownian motors

NASA Astrophysics Data System (ADS)

Li, Chen-Pu; Chen, Hong-Bin; Zheng, Zhi-Gang

2017-12-01

On the basis of the transport features and experimental phenomena observed in studies of molecular motors, we propose a double-temperature ratchet model of coupled motors to reveal the dynamical mechanism of cooperative transport of motors with two heads, where the interactions and asynchrony between two motor heads are taken into account. We investigate the collective unidirectional transport of coupled system and find that the direction of motion can be reversed under certain conditions. Reverse motion can be achieved by modulating the coupling strength, coupling free length, and asymmetric coefficient of the periodic potential, which is understood in terms of the effective potential theory. The dependence of the directed current on various parameters is studied systematically. Directed transport of coupled Brownian motors can be manipulated and optimized by adjusting the pulsation period or the phase shift of the pulsation temperature.

Nanomanipulation-coupled nanospray mass spectrometry as an approach for single cell analysis

NASA Astrophysics Data System (ADS)

Phelps, Mandy; Hamilton, Jason; Verbeck, Guido F.

2014-12-01

Electrospray mass spectrometry is now a widely used technique for observing cell content of various biological tissues. However, electrospray techniques (liquid chromatography and direct infusion) often involve lysing a group of cells and extracting the biomolecules of interest, rather than a sensitive, individual cell method to observe local chemistry. Presented here is an approach of combining a nanomanipulator workstation with nanospray mass spectrometry, which allows for extraction of a single cell, followed by rapid mass analysis that can provide a detailed metabolic profile. Triacylglycerol content was profiled with this tool coupled to mass spectrometry to investigate heterogeneity between healthy and tumorous tissues as well as lipid droplet containing adipocytes in vitro as proof of concept. This selective approach provides cellular resolution and complements existing bioanalytical techniques with minimal invasion to samples. In addition, the coupling of nanomanipulation and mass spectrometry holds the potential to be used in a great number of applications for individual organelles, diseased tissues, and in vitro cell cultures for observing heterogeneity even amongst cells and organelles of the same tissue.

The Coupling of Macrosegregation with Grain Nucleation, Growth and Motion in DC Cast Aluminum Alloy Ingots

NASA Astrophysics Data System (ADS)

Založnik, Miha; Kumar, Arvind; Combeau, Hervé; Bedel, Marie; Jarry, Philippe; Waz, Emmanuel

The phenomena responsible for the formation of macrosegregations, and grain structures during solidification are closely intertwined. We present a model study of the formation of macrosegregation and grain structure in an industrial sized (350 mm thick) direct chill (DC) cast aluminum alloy slab. The modeling of these phenomena in DC casting is a challenging problem mainly due to the size of the products, the variety of the phenomena to be accounted for, and the non-linearities involved. We used a volume-averaged multiscale model that describes nucleation on grain refiner particles and grain growth, coupled with macroscopic transport: fluid flow driven by natural convection and shrinkage, transport of free-floating globular equiaxed grains, heat transfer, and solute transport. We analyze the heat and mass transfer in the slurry moving-grain zone that is a result of the coupling of the fluid flow and of the grain nucleation, growth and motion. We discuss the impact of the flow structure in the slurry zone and of the grain packing fraction on the macrosegregation.

Estimate the effective connectivity in multi-coupled neural mass model using particle swarm optimization

NASA Astrophysics Data System (ADS)

Shan, Bonan; Wang, Jiang; Deng, Bin; Zhang, Zhen; Wei, Xile

2017-03-01

Assessment of the effective connectivity among different brain regions during seizure is a crucial problem in neuroscience today. As a consequence, a new model inversion framework of brain function imaging is introduced in this manuscript. This framework is based on approximating brain networks using a multi-coupled neural mass model (NMM). NMM describes the excitatory and inhibitory neural interactions, capturing the mechanisms involved in seizure initiation, evolution and termination. Particle swarm optimization method is used to estimate the effective connectivity variation (the parameters of NMM) and the epileptiform dynamics (the states of NMM) that cannot be directly measured using electrophysiological measurement alone. The estimated effective connectivity includes both the local connectivity parameters within a single region NMM and the remote connectivity parameters between multi-coupled NMMs. When the epileptiform activities are estimated, a proportional-integral controller outputs control signal so that the epileptiform spikes can be inhibited immediately. Numerical simulations are carried out to illustrate the effectiveness of the proposed framework. The framework and the results have a profound impact on the way we detect and treat epilepsy.

Natural supersymmetry without light Higgsinos

DOE PAGES

Cohen, Timothy; Kearney, John; Luty, Markus A.

2015-04-08

In this study, we present a mechanism that allows a large Higgsino mass without large fine-tuning. The Higgs is a pseudo-Nambu-Goldstone boson (PNGB) of the global symmetry breaking pattern SO(5)→SO(4). Because of the PNGB nature of the light Higgs, the SO(5) invariant Higgsino mass does not directly contribute to the Higgs mass. Large couplings in the Higgs sector that spontaneously breaks SO(5) minimize the tuning, and are also motivated by the requirements of generating a sufficiently large Higgs quartic coupling and of maintaining a natural approximate global SO(5) symmetry. When these conditions are imposed, theories of this type predict heavymore » Higgsinos. This construction differs from composite Higgs models in that no new particles are introduced to form complete SO(5) multiplets involving the top quark—the stop is the only top partner. Compatibility with Higgs coupling measurements requires cancellations among contributions to the Higgs mass-squared parameter at the 10% level. An important implication of this construction is that the compressed region of stop and sbottom searches can still be natural.« less

A Lever Coupling Mechanism in Dual-Mass Micro-Gyroscopes for Improving the Shock Resistance along the Driving Direction

PubMed Central

Gao, Yang; Li, Hongsheng; Huang, Libin; Sun, Hui

2017-01-01

This paper presents the design and application of a lever coupling mechanism to improve the shock resistance of a dual-mass silicon micro-gyroscope with drive mode coupled along the driving direction without sacrificing the mechanical sensitivity. Firstly, the mechanical sensitivity and the shock response of the micro-gyroscope are theoretically analyzed. In the mechanical design, a novel lever coupling mechanism is proposed to change the modal order and to improve the frequency separation. The micro-gyroscope with the lever coupling mechanism optimizes the drive mode order, increasing the in-phase mode frequency to be much larger than the anti-phase one. Shock analysis results show that the micro-gyroscope structure with the designed lever coupling mechanism can notably reduce the magnitudes of the shock response and cut down the stress produced in the shock process compared with the traditional elastic coupled one. Simulations reveal that the shock resistance along the drive direction is greatly increased. Consequently, the lever coupling mechanism can change the gyroscope’s modal order and improve the frequency separation by structurally offering a higher stiffness difference ratio. The shock resistance along the driving direction is tremendously enhanced without loss of the mechanical sensitivity. PMID:28468288

Sls1p is a membrane-bound regulator of transcription-coupled processes involved in Saccharomyces cerevisiae mitochondrial gene expression.

PubMed Central

Bryan, Anthony C; Rodeheffer, Matthew S; Wearn, Christopher M; Shadel, Gerald S

2002-01-01

Mitochondrial translation is largely membrane-associated in S. cerevisiae. Recently, we discovered that the matrix protein Nam1p binds the amino-terminal domain of yeast mtRNA polymerase to couple translation and/or RNA-processing events to transcription. To gain additional insight into these transcription-coupled processes, we performed a genetic screen for genes that suppress the petite phenotype of a point mutation in mtRNA polymerase (rpo41-R129D) when overexpressed. One suppressor identified in this screen was SLS1, which encodes a mitochondrial membrane protein required for assembly of respiratory-chain enzyme complexes III and IV. The mtRNA-processing defects associated with the rpo41-R129D mutation were corrected in the suppressed strain, linking Sls1p to a pathway that includes mtRNA polymerase and Nam1p. This was supported by the observation that SLS1 overexpression rescued the petite phenotype of a NAM1 null mutation. In contrast, overexpression of Nam1p did not rescue the petite phenotype of a SLS1 null mutation, indicating that Nam1p and Sls1p are not functionally redundant but rather exist in an ordered pathway. On the basis of these data, a model in which Nam1p coordinates the delivery of newly synthesized transcripts to the membrane, where Sls1p directs or regulates their subsequent handling by membrane-bound factors involved in translation, is proposed. PMID:11805046

Importance of Hydrophobic Cavities in Allosteric Regulation of Formylglycinamide Synthetase: Insight from Xenon Trapping and Statistical Coupling Analysis

PubMed Central

Choudhary, Deepanshu; Panjikar, Santosh; Anand, Ruchi

2013-01-01

Formylglycinamide ribonucleotide amidotransferase (FGAR-AT) is a 140 kDa bi-functional enzyme involved in a coupled reaction, where the glutaminase active site produces ammonia that is subsequently utilized to convert FGAR to its corresponding amidine in an ATP assisted fashion. The structure of FGAR-AT has been previously determined in an inactive state and the mechanism of activation remains largely unknown. In the current study, hydrophobic cavities were used as markers to identify regions involved in domain movements that facilitate catalytic coupling and subsequent activation of the enzyme. Three internal hydrophobic cavities were located by xenon trapping experiments on FGAR-AT crystals and further, these cavities were perturbed via site-directed mutagenesis. Biophysical characterization of the mutants demonstrated that two of these three voids are crucial for stability and function of the protein, although being ∼20 Å from the active centers. Interestingly, correlation analysis corroborated the experimental findings, and revealed that amino acids lining the functionally important cavities form correlated sets (co-evolving residues) that connect these regions to the amidotransferase active center. It was further proposed that the first cavity is transient and allows for breathing motion to occur and thereby serves as an allosteric hotspot. In contrast, the third cavity which lacks correlated residues was found to be highly plastic and accommodated steric congestion by local adjustment of the structure without affecting either stability or activity. PMID:24223728

Proton-coupled organic cation antiporter-mediated uptake of apomorphine enantiomers in human brain capillary endothelial cell line hCMEC/D3.

PubMed

Okura, Takashi; Higuchi, Kei; Kitamura, Atsushi; Deguchi, Yoshiharu

2014-01-01

R(-)-Apomorphine is a dopamine agonist used for rescue management of motor function impairment associated with levodopa therapy in Parkinson's disease patients. The aim of this study was to examine the role of proton-coupled organic cation antiporter in uptake of R(-)-apomorphine and its S-enantiomer in human brain, using human endothelial cell line hCMEC/D3 as a model. Uptake of R(-)- or S(+)-apomorphine into hCMEC/D3 cells was measured under various conditions to evaluate its time-, concentration-, energy- and ion-dependency. Inhibition by selected organic cations was also examined. Uptakes of both R(-)- and S(+)-apomorphine increased with time. The initial uptake velocities of R(-)- and S(+)-apomorphine were concentration-dependent, with similar Km and Vmax values. The cell-to-medium (C/M) ratio of R(-)-apomorphine was significantly reduced by pretreatment with sodium azide, but was not affected by replacement of extracellular sodium ion with N-methylglucamine or potassium. Intracellular alkalization markedly reduced the uptake, while intracellular acidification increased it, suggesting that the uptake is driven by an oppositely directed proton gradient. The C/M ratio was significantly decreased by amantadine, verapamil, pyrilamine and diphenhydramine (substrates or inhibitors of proton-coupled organic cation antiporter), while tetraethylammonium (substrate of organic cation transporters (OCTs)) and carnitine (substrate of carnitine/organic cation transporter 2; (OCTN2)) had no effect. R(-)-Apomorphine uptake was competitively inhibited by diphenhydramine. Our results indicate that R(-)-apomorphine transport in human blood-brain barrier (BBB) model cells is similar to S(+)-apomorphine uptake. The transport was dependent on an oppositely directed proton gradient, but was sodium- or membrane potential-independent. The transport characteristics were consistent with involvement of the previously reported proton-coupled organic cation antiporter.

Voltage control of magnetism in NiZn ferrite/mica/PMNPT heterostructure with giant tunability and narrow linewidth

NASA Astrophysics Data System (ADS)

Wang, Xinjun; Chen, Yunpeng; Chen, Huaihao; Gao, Yuan; He, Yifan; Li, Menghui; Lin, Hwaider; Sun, Neville; Sun, Nian

2018-05-01

Recently, large magnetoelectric coupling of a spinel/piezoelectric heterostructure has been reported. However, the linewidth of the spinel is very large due to lattice mismatch when ferrite is directly deposited on piezoelectric substrates. This indicates a large magnetic loss, which impedes the spinel/piezoelectric heterostructure from useful device applications. Mica is a well-known 2D material, which can be split manually layer by layer without the substrate clamping effect. In this report, NiZn ferrite was deposited on a mica substrate by a spin-spray deposition technique. Spin-spray deposition is a wet chemical synthesis technique involving several chemical reactions for generating high-quality crystalline spinel ferrite films with various compositions directly from an aqueous solution. The thickness of ferrite is 2 μm, and the linewidth of the ferromagnetic resonance (FMR) is 115 Oe which is suitable for RF/microwave devices. The large FMR field tuning of 605 Oe was observed in NiZn ferrite/mica/PMN-PT heterostructures with minimal substrate clamping effect by reducing the thickness of the mica substrate. These multiferroic heterostructures exhibiting combined giant magnetoelectric coupling and narrow ferromagnetic resonance linewidth offer great opportunities for flexible RF magnetic devices.

Direct and sensitive determination of glyphosate and aminomethylphosphonic acid in environmental water samples by high performance liquid chromatography coupled to electrospray tandem mass spectrometry.

PubMed

Guo, Hongyue; Riter, Leah S; Wujcik, Chad E; Armstrong, Daniel W

2016-04-22

A novel method based on high performance liquid chromatography coupled to tandem mass spectrometry (HPLC-MS/MS) was developed for the sensitive determination of glyphosate and its major degradation product, AMPA in environmental water samples. The method involves the use of MS compatible mobile phases (0.1% formic acid in water and acetonitrile) for HPLC and direct analysis of water samples without sample derivatization. The method has been validated in different types of water matrices (drinking, surface and groundwater) by accuracy and precision studies with samples spiked at 0.1, 7.5 and 90 ppb. All mean accuracy values ranged from 85% to 112% for glyphosate and AMPA using both primary and secondary quantitative ion transitions (RSD ≤ 10%). Moreover, both primary and secondary ion transitions for glyphosate and AMPA can achieve the quantitation limits at 0.1 ppb. The linear dynamic range of the calibration curves were from 0.1 to 100 ppb for each analyte at each ion transitions with correlation coefficient higher than 0.997. Copyright © 2016 Elsevier B.V. All rights reserved.

Studies of fission fragment yields via high-resolution γ-ray spectroscopy

NASA Astrophysics Data System (ADS)

Wilson, J. N.; Lebois, M.; Qi, L.; Amador-Celdran, P.; Bleuel, D.; Briz, J. A.; Carroll, R.; Catford, W.; Witte, H. De; Doherty, D. T.; Eloirdi, R.; Georgiev, G.; Gottardo, A.; Goasduff, A.; Hadyñska-Klek, K.; Hauschild, K.; Hess, H.; Ingeberg, V.; Konstantinopoulos, T.; Ljungvall, J.; Lopez-Martens, A.; Lorusso, G.; Lozeva, R.; Lutter, R.; Marini, P.; Matea, I.; Materna, T.; Mathieu, L.; Oberstedt, A.; Oberstedt, S.; Panebianco, S.; Podolyak, Zs.; Porta, A.; Regan, P. H.; Reiter, P.; Rezynkina, K.; Rose, S. J.; Sahin, E.; Seidlitz, M.; Serot, O.; Shearman, R.; Siebeck, B.; Siem, S.; Smith, A. G.; Tveten, G. M.; Verney, D.; Warr, N.; Zeiser, F.; Zielinska, M.

2018-03-01

Precise spectroscopic information on the fast neutron induced fission of the 238U(n,f) reaction was recently gained using a new technique which involved coupling of the Miniball high resolution y-ray spectrometer and the LICORNE directional neutron source. The experiment allowed measurement of the isotopic fission yields for around 40 even-even nuclei at an incident neutron energy of around 2 MeV where yield data are very sparse. In addition spectroscopic information on very neutron-rich fission products was obtained. Results were compared to models, both the JEFF-3.1.1 data base and the GEF code, and large discrepancies for the S1 fission mode in the Sn/Mo isotope pair were discovered. This suggests that current models are overestimating the role played by spherical shell effects in fast neutron induced fission. In late 2017 and 2018 the nu-ball hybrid spectrometer will be constructed at the IPN Orsay to perform further experimental investigations with directional neutrons coupled to a powerful hybrid Ge/LaBr3 detector array. This will open up new possibilities for measurements of fission yields for fast-neutron-induced fission using the spectroscopic technique and will be complimentary to other methods being developed.

Robust Adaptive Synchronization of Ring Configured Uncertain Chaotic FitzHugh–Nagumo Neurons under Direction-Dependent Coupling

PubMed Central

Iqbal, Muhammad; Rehan, Muhammad; Hong, Keum-Shik

2018-01-01

This paper exploits the dynamical modeling, behavior analysis, and synchronization of a network of four different FitzHugh–Nagumo (FHN) neurons with unknown parameters linked in a ring configuration under direction-dependent coupling. The main purpose is to investigate a robust adaptive control law for the synchronization of uncertain and perturbed neurons, communicating in a medium of bidirectional coupling. The neurons are assumed to be different and interconnected in a ring structure. The strength of the gap junctions is taken to be different for each link in the network, owing to the inter-neuronal coupling medium properties. Robust adaptive control mechanism based on Lyapunov stability analysis is employed and theoretical criteria are derived to realize the synchronization of the network of four FHN neurons in a ring form with unknown parameters under direction-dependent coupling and disturbances. The proposed scheme for synchronization of dissimilar neurons, under external electrical stimuli, coupled in a ring communication topology, having all parameters unknown, and subject to directional coupling medium and perturbations, is addressed for the first time as per our knowledge. To demonstrate the efficacy of the proposed strategy, simulation results are provided. PMID:29535622

The heartbreak of depression: 'Psycho-cardiac' coupling in myocardial infarction.

PubMed

Headrick, John P; Peart, Jason N; Budiono, Boris P; Shum, David H K; Neumann, David L; Stapelberg, Nicolas J C

2017-05-01

Ample evidence identifies strong links between major depressive disorder (MDD) and both risk of ischemic or coronary heart disease (CHD) and resultant morbidity and mortality. The molecular mechanistic bases of these linkages are poorly defined. Systemic factors linked to MDD, including vascular dysfunction, atherosclerosis, obesity and diabetes, together with associated behavioral changes, all elevate CHD risk. Nonetheless, experimental evidence indicates the myocardium is also directly modified in depression, independently of these factors, impairing infarct tolerance and cardioprotection. It may be that MDD effectively breaks the heart's intrinsic defense mechanisms. Four extrinsic processes are implicated in this psycho-cardiac coupling, presenting potential targets for therapeutic intervention if causally involved: sympathetic over-activity vs. vagal under-activity, together with hypothalamic-pituitary-adrenal (HPA) axis and immuno-inflammatory dysfunctions. However, direct evidence of their involvement remains limited, and whether targeting these upstream mediators is effective (or practical) in limiting the cardiac consequences of MDD is unknown. Detailing myocardial phenotype in MDD can also inform approaches to cardioprotection, yet cardiac molecular changes are similarly ill defined. Studies support myocardial sensitization to ischemic insult in models of MDD, including worsened oxidative and nitrosative damage, apoptosis (with altered Bcl-2 family expression) and infarction. Moreover, depression may de-sensitize hearts to protective conditioning stimuli. The mechanistic underpinnings of these changes await delineation. Such information not only advances our fundamental understanding of psychological determinants of health, but also better informs management of the cardiac consequences of MDD and implementing cardioprotection in this cohort. Copyright © 2017 Elsevier Ltd. All rights reserved.

Tilt to horizontal global solar irradiance conversion: application to PV systems data

NASA Astrophysics Data System (ADS)

Housmans, Caroline; Leloux, Jonathan; Bertrand, Cédric

2017-04-01

Many transposition models have been proposed in the literature to convert solar irradiance on the horizontal plane to that on a tilted plane requiring that at least two of the three solar components (i.e. global, direct and diffuse) are known. When only global irradiance measurements are available, the conversion from horizontal to tilted planes is still possible but in this case transposition models have to be coupled with decomposition models (i.e. models that predict the direct and diffuse components from the global one). Here, two different approaches have been considered to solve the reverse process, i.e. the conversion from tilted to horizontal: (i) one-sensor approach and (ii) multi-sensors approach. Because only one tilted plane is involved in the one-sensor approach, a decomposition model need to be coupled with a transposition model to solve the problem. By contrast, at least two tilted planes being considered in the multi-sensors approach, only a transposition model is required to perform the conversion. First, global solar irradiance measurements recorded on the roof of the Royal Meteorological Institute of Belgium's radiation tower in Uccle were used to evaluate the performance of both approaches. Four pyranometers (one mounted in the horizontal plane and three on inclined surfaces with different tilts and orientations) were involved in the validation exercise. Second, the inverse transposition was applied to tilted global solar irradiance values retrieved from the energy production registered at residential PV systems located in the vicinity of Belgian radiometric stations operated by RMI (for validation purposes).

An Embedded Statistical Method for Coupling Molecular Dynamics and Finite Element Analyses

NASA Technical Reports Server (NTRS)

Saether, E.; Glaessgen, E.H.; Yamakov, V.

2008-01-01

The coupling of molecular dynamics (MD) simulations with finite element methods (FEM) yields computationally efficient models that link fundamental material processes at the atomistic level with continuum field responses at higher length scales. The theoretical challenge involves developing a seamless connection along an interface between two inherently different simulation frameworks. Various specialized methods have been developed to solve particular classes of problems. Many of these methods link the kinematics of individual MD atoms with FEM nodes at their common interface, necessarily requiring that the finite element mesh be refined to atomic resolution. Some of these coupling approaches also require simulations to be carried out at 0 K and restrict modeling to two-dimensional material domains due to difficulties in simulating full three-dimensional material processes. In the present work, a new approach to MD-FEM coupling is developed based on a restatement of the standard boundary value problem used to define a coupled domain. The method replaces a direct linkage of individual MD atoms and finite element (FE) nodes with a statistical averaging of atomistic displacements in local atomic volumes associated with each FE node in an interface region. The FEM and MD computational systems are effectively independent and communicate only through an iterative update of their boundary conditions. With the use of statistical averages of the atomistic quantities to couple the two computational schemes, the developed approach is referred to as an embedded statistical coupling method (ESCM). ESCM provides an enhanced coupling methodology that is inherently applicable to three-dimensional domains, avoids discretization of the continuum model to atomic scale resolution, and permits finite temperature states to be applied.

A New Concurrent Multiscale Methodology for Coupling Molecular Dynamics and Finite Element Analyses

NASA Technical Reports Server (NTRS)

Yamakov, Vesselin; Saether, Erik; Glaessgen, Edward H/.

2008-01-01

The coupling of molecular dynamics (MD) simulations with finite element methods (FEM) yields computationally efficient models that link fundamental material processes at the atomistic level with continuum field responses at higher length scales. The theoretical challenge involves developing a seamless connection along an interface between two inherently different simulation frameworks. Various specialized methods have been developed to solve particular classes of problems. Many of these methods link the kinematics of individual MD atoms with FEM nodes at their common interface, necessarily requiring that the finite element mesh be refined to atomic resolution. Some of these coupling approaches also require simulations to be carried out at 0 K and restrict modeling to two-dimensional material domains due to difficulties in simulating full three-dimensional material processes. In the present work, a new approach to MD-FEM coupling is developed based on a restatement of the standard boundary value problem used to define a coupled domain. The method replaces a direct linkage of individual MD atoms and finite element (FE) nodes with a statistical averaging of atomistic displacements in local atomic volumes associated with each FE node in an interface region. The FEM and MD computational systems are effectively independent and communicate only through an iterative update of their boundary conditions. With the use of statistical averages of the atomistic quantities to couple the two computational schemes, the developed approach is referred to as an embedded statistical coupling method (ESCM). ESCM provides an enhanced coupling methodology that is inherently applicable to three-dimensional domains, avoids discretization of the continuum model to atomic scale resolution, and permits finite temperature states to be applied.

Event-based cluster synchronization of coupled genetic regulatory networks

NASA Astrophysics Data System (ADS)

Yue, Dandan; Guan, Zhi-Hong; Li, Tao; Liao, Rui-Quan; Liu, Feng; Lai, Qiang

2017-09-01

In this paper, the cluster synchronization of coupled genetic regulatory networks with a directed topology is studied by using the event-based strategy and pinning control. An event-triggered condition with a threshold consisting of the neighbors' discrete states at their own event time instants and a state-independent exponential decay function is proposed. The intra-cluster states information and extra-cluster states information are involved in the threshold in different ways. By using the Lyapunov function approach and the theories of matrices and inequalities, we establish the cluster synchronization criterion. It is shown that both the avoidance of continuous transmission of information and the exclusion of the Zeno behavior are ensured under the presented triggering condition. Explicit conditions on the parameters in the threshold are obtained for synchronization. The stability criterion of a single GRN is also given under the reduced triggering condition. Numerical examples are provided to validate the theoretical results.

Mechanism and Kinetics of Ethanol Coupling to Butanol over Hydroxyapatite

DOE PAGES

Ho, Christopher R.; Shylesh, Sankaranarayanapillai; Bell, Alexis T.

2015-12-23

The mechanism and kinetics for ethanol coupling to n-butanol over hydroxyapatite (HAP) were investigated at 573-613 K. In situ titration experiments show that the active sites for acetaldehyde and butanol formation are different. In combination with FTIR studies, it was found that ethanol dehydrogenation is catalyzed by Ca-O sites, whereas condensation of acetaldehyde is catalyzed by CaO/PO 4 3- pairs. Measurements of the reaction kinetics at various ethanol (3.5-9.4 kPa) and acetaldehyde (0.055-0.12 kPa) partial pressures reveal that direct condensation involving two ethanol molecules does not play a significant role in butanol formation; instead, n-butanol is formed via a Guerbetmore » pathway. At a constant acetaldehyde pressure, enolate formation is rate-limiting, and ethanol inhibits acetaldehyde condensation rates by competitive adsorption. A model of the reaction kinetics consistent with all experimental observations is developed.« less

Haem-activated promiscuous targeting of artemisinin in Plasmodium falciparum.

PubMed

Wang, Jigang; Zhang, Chong-Jing; Chia, Wan Ni; Loh, Cheryl C Y; Li, Zhengjun; Lee, Yew Mun; He, Yingke; Yuan, Li-Xia; Lim, Teck Kwang; Liu, Min; Liew, Chin Xia; Lee, Yan Quan; Zhang, Jianbin; Lu, Nianci; Lim, Chwee Teck; Hua, Zi-Chun; Liu, Bin; Shen, Han-Ming; Tan, Kevin S W; Lin, Qingsong

2015-12-22

The mechanism of action of artemisinin and its derivatives, the most potent of the anti-malarial drugs, is not completely understood. Here we present an unbiased chemical proteomics analysis to directly explore this mechanism in Plasmodium falciparum. We use an alkyne-tagged artemisinin analogue coupled with biotin to identify 124 artemisinin covalent binding protein targets, many of which are involved in the essential biological processes of the parasite. Such a broad targeting spectrum disrupts the biochemical landscape of the parasite and causes its death. Furthermore, using alkyne-tagged artemisinin coupled with a fluorescent dye to monitor protein binding, we show that haem, rather than free ferrous iron, is predominantly responsible for artemisinin activation. The haem derives primarily from the parasite's haem biosynthesis pathway at the early ring stage and from haemoglobin digestion at the latter stages. Our results support a unifying model to explain the action and specificity of artemisinin in parasite killing.

Haem-activated promiscuous targeting of artemisinin in Plasmodium falciparum

PubMed Central

Wang, Jigang; Zhang, Chong-Jing; Chia, Wan Ni; Loh, Cheryl C. Y.; Li, Zhengjun; Lee, Yew Mun; He, Yingke; Yuan, Li-Xia; Lim, Teck Kwang; Liu, Min; Liew, Chin Xia; Lee, Yan Quan; Zhang, Jianbin; Lu, Nianci; Lim, Chwee Teck; Hua, Zi-Chun; Liu, Bin; Shen, Han-Ming; Tan, Kevin S. W.; Lin, Qingsong

2015-01-01

The mechanism of action of artemisinin and its derivatives, the most potent of the anti-malarial drugs, is not completely understood. Here we present an unbiased chemical proteomics analysis to directly explore this mechanism in Plasmodium falciparum. We use an alkyne-tagged artemisinin analogue coupled with biotin to identify 124 artemisinin covalent binding protein targets, many of which are involved in the essential biological processes of the parasite. Such a broad targeting spectrum disrupts the biochemical landscape of the parasite and causes its death. Furthermore, using alkyne-tagged artemisinin coupled with a fluorescent dye to monitor protein binding, we show that haem, rather than free ferrous iron, is predominantly responsible for artemisinin activation. The haem derives primarily from the parasite's haem biosynthesis pathway at the early ring stage and from haemoglobin digestion at the latter stages. Our results support a unifying model to explain the action and specificity of artemisinin in parasite killing. PMID:26694030

Feasibility study of a swept frequency electromagnetic probe (SWEEP) using inductive coupling for the determination of subsurface conductivity of the earth and water prospecting in arid regions

NASA Technical Reports Server (NTRS)

Latorraca, G. A.; Bannister, L. H.

1974-01-01

Techniques developed for electromagnetic probing of the lunar interior, and techniques developed for the generation of high power audio frequencies were combined to make practical a magnetic inductive coupling system for the rapid measurement of ground conductivity profiles which are helpful when prospecting for the presence and quality of subsurface water. A system which involves the measurement of the direction, intensity, and time phase of the magnetic field observed near the surface of the earth at a distance from a horizontal coil energized so as to create a field that penetrates the earth was designed and studied to deduce the conductivity and stratification of the subsurface. Theoretical studies and a rudimentary experiment in an arid region showed that the approach is conceptually valid and that this geophysical prospecting technique can be developed for the economical exploration of subterranean water resources.

Superconductor-insulator transition in a stripe-ordered cuprate

NASA Astrophysics Data System (ADS)

Tranquada, John; Homes, C.; Gu, G. D.; Li, Q.; Huecker, M.

We reconsider the case of La2-xBaxCuO4 with x = 1 / 8 , where spin-stripe order and 2D superconducting correlations develop simultaneously at 40 K. The thermal evolution of the in-plane optical reflectivity suggests the development of a Josephson plasma resonance (JPR) between charge stripes, by analogy with the JPR seen in c-axis reflectivity in the superconducting state of Josephson-coupled CuO2 planes. At low-temperature, when the superconductivity is suppressed by a magnetic field, the resistivity exhibits insulating character. We interpret this as suppression of the Josephson coupling between pair correlations in neighboring charge stripes, with single-particle transport suppressed by the surviving spin-stripe order. To obtain direct evidence that the high-field insulator involves hole pairs localized to 1D stripes will require further experiments. Work at BNL supported by Office of Basic Energy Sciences, US DOE, under Contract No. DE-SC0012704.

Single array of magnetic vortex disks uses in-plane anisotropy to create different logic gates

NASA Astrophysics Data System (ADS)

Vigo-Cotrina, H.; Guimarães, A. P.

2017-11-01

Using micromagnetic simulation, we show that in-plane uniaxial magnetic anisotropy (IPUA) can be used to obtain FAN-OUT, AND and OR gates in an array of coupled disks with magnetic vortex configuration. First, we studied the influence of the direction of application of the IPUA on the energy transfer time (τ) between two identical coupled nanodisks. We found that when the direction of the IPUA is along the x axis the magnetic interaction increases, allowing shorter values of τ , while the IPUA along the y direction has the opposite effect. The magnetic interactions between the nanodisks along x and y directions (the coupling integrals) as a function of the uniaxial anisotropy constant (Kσ) were obtained using a simple dipolar model. Next, we demonstrated that choosing a suitable direction of application of the IPUA, it is possible to create several different logic gates with a single array of coupled nanodisks.

Direct Observation of Insulin Association Dynamics with Time-Resolved X-ray Scattering

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rimmerman, Dolev; Leshchev, Denis; Hsu, Darren J.

Biological functions frequently require protein-protein interactions that involve secondary and tertiary structural perturbation. Here we study protein-protein dissociation and reassociation dynamics in insulin, a model system for protein oligomerization. Insulin dimer dissociation into monomers was induced by a nanosecond temperature-jump (T-jump) of ~8 °C in aqueous solution, and the resulting protein and solvent dynamics were tracked by time-resolved X-ray solution scattering (TRXSS) on time scales of 10 ns to 100 ms. The protein scattering signals revealed the formation of five distinguishable transient species during the association process that deviate from simple two state kinetics. Our results show that the combinationmore » of T-jump pump coupled to TRXSS probe allows for direct tracking of structural dynamics in nonphotoactive proteins.« less

Teradiode's high brightness semiconductor lasers

NASA Astrophysics Data System (ADS)

Huang, Robin K.; Chann, Bien; Burgess, James; Lochman, Bryan; Zhou, Wang; Cruz, Mike; Cook, Rob; Dugmore, Dan; Shattuck, Jeff; Tayebati, Parviz

2016-03-01

TeraDiode is manufacturing multi-kW-class ultra-high brightness fiber-coupled direct diode lasers for industrial applications. A fiber-coupled direct diode laser with a power level of 4,680 W from a 100 μm core diameter, <0.08 numerical aperture (NA) output fiber at a single center wavelength was demonstrated. Our TeraBlade industrial platform achieves world-record brightness levels for direct diode lasers. The fiber-coupled output corresponds to a Beam Parameter Product (BPP) of 3.5 mm-mrad and is the lowest BPP multi-kW-class direct diode laser yet reported. This laser is suitable for industrial materials processing applications, including sheet metal cutting and welding. This 4-kW fiber-coupled direct diode laser has comparable brightness to that of industrial fiber lasers and CO2 lasers, and is over 10x brighter than state-of-the-art direct diode lasers. We have also demonstrated novel high peak power lasers and high brightness Mid-Infrared Lasers.

Thermal transport across metal silicide-silicon interfaces: First-principles calculations and Green's function transport simulations

NASA Astrophysics Data System (ADS)

Sadasivam, Sridhar; Ye, Ning; Feser, Joseph P.; Charles, James; Miao, Kai; Kubis, Tillmann; Fisher, Timothy S.

2017-02-01

Heat transfer across metal-semiconductor interfaces involves multiple fundamental transport mechanisms such as elastic and inelastic phonon scattering, and electron-phonon coupling within the metal and across the interface. The relative contributions of these different transport mechanisms to the interface conductance remains unclear in the current literature. In this work, we use a combination of first-principles calculations under the density functional theory framework and heat transport simulations using the atomistic Green's function (AGF) method to quantitatively predict the contribution of the different scattering mechanisms to the thermal interface conductance of epitaxial CoSi2-Si interfaces. An important development in the present work is the direct computation of interfacial bonding from density functional perturbation theory (DFPT) and hence the avoidance of commonly used "mixing rules" to obtain the cross-interface force constants from bulk material force constants. Another important algorithmic development is the integration of the recursive Green's function (RGF) method with Büttiker probe scattering that enables computationally efficient simulations of inelastic phonon scattering and its contribution to the thermal interface conductance. First-principles calculations of electron-phonon coupling reveal that cross-interface energy transfer between metal electrons and atomic vibrations in the semiconductor is mediated by delocalized acoustic phonon modes that extend on both sides of the interface, and phonon modes that are localized inside the semiconductor region of the interface exhibit negligible coupling with electrons in the metal. We also provide a direct comparison between simulation predictions and experimental measurements of thermal interface conductance of epitaxial CoSi2-Si interfaces using the time-domain thermoreflectance technique. Importantly, the experimental results, performed across a wide temperature range, only agree well with predictions that include all transport processes: elastic and inelastic phonon scattering, electron-phonon coupling in the metal, and electron-phonon coupling across the interface.

The role of satellite directional wave spectra for the improvement of the ocean-waves coupling

NASA Astrophysics Data System (ADS)

Aouf, Lotfi; Hauser, Danièle; Chapron, Bertrand

2017-04-01

Swell waves are well captured by the Synthetic Aperture Radar (SAR) which provides the directional wave spectra for waves roughly larger than 200 m. Since the launch of sentinel-1A and 1B SAR directional wave spectra are available to improve the swell wave forecasting and the coupling processes at the air-sea interface. Moreover next year CFOSAT mission will provide directional wave spectra for waves with wavelengths comprised between 70 to 500 m. This study aims to evaluate the assimilation of SAR and synthetic CFOSAT wave spectra on the coupling between the wave model MFWAM and the ocean model NEMO. Three coupling processes as described in Breivik et al. (2014) of Stokes-Coriolis forcing, the ocean side stress and the turbulence injected by the wave breaking in the ocean mixed layer have been used. a coupling run is performed with and without assimilation of directional wave spectra. the impact of SAR wave data on key parameters such as surface sea temperature, currents and salinity is investigated. Particular attention is carried out for ocean areas with swell dominant wave climate.

Transepithelial transport of flavanone in intestinal Caco-2 cell monolayers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kobayashi, Shoko; Konishi, Yutaka

2008-03-28

Our recent study [S. Kobayashi, S. Tanabe, M. Sugiyama, Y. Konishi, Transepithelial transport of hesperetin and hesperidin in intestinal Caco-2 cell monolayers, Biochim. Biophys. Acta, 1778 (2008) 33-41] shows that the mechanism of absorption of hesperetin involves both proton-coupled active transport and transcellular passive diffusion. Here, as well as analyzing the cell permeability of hesperetin, we also study the transport of other flavanones, naringenin and eriodictyol, using Caco-2 cell monolayers. Similar to hesperetin mentioned, naringenin and eriodictyol showed proton-coupled polarized transport in apical-to-basolateral direction in non-saturable manner, constant permeation in the apical-to-basolateral direction (J{sub ap{yields}}{sub bl}) irrespective of the transepithelialmore » electrical resistance (TER), and preferable distribution into the basolateral side after apical loading in the presence of a proton gradient. Furthermore, the proton-coupled J{sub ap{yields}}{sub bl} of hesperetin, naringenin and eriodictyol, were inhibited by substrates of the monocarboxylic acid transporter (MCT), such as benzoic acid, but not by ferulic acid. In contrast, both benzoic and ferulic acids have no stimulatory effect on J{sub ap{yields}}{sub bl} of each flavanone by trans-stimulation analysis. These results indicates that proton-driven active transport is commonly participated in the absorption of flavanone in general, and that its transport is presumed to be unique other than MCT-mediated transport for absorption of phenolic acids (PAs), sodium-dependent MCT (SMCT) nor anion exchanger-mediated transport.« less

Extremely high-brightness kW-class fiber coupled diode lasers with wavelength stabilization

NASA Astrophysics Data System (ADS)

Huang, Robin K.; Chann, Bien; Glenn, John D.

2011-06-01

TeraDiode has produced ultra-high brightness fiber-coupled direct diode lasers. A fiber-coupled direct diode laser with a power level of 1,040 W from a 200 μm core diameter, 0.18 numerical aperture (NA) output fiber at a single center wavelength was demonstrated. This was achieved with a novel beam combining and shaping technique using COTS diode lasers. The fiber-coupled output corresponds to a Beam Parameter Product (BPP) of 18 mm-mrad and is the lowest BPP kW-class direct diode laser yet reported. The laser has been used to demonstrate laser cutting and welding of steel sheet metal up to 6.65 mm thick. Higher brightness fiber-coupled diode lasers, including a module with 418 W of power coupled to a 100 μm, 0.15 NA fiber, have also been demonstrated.

Methyl Radicals in Oxidative Coupling of Methane Directly Confirmed by Synchrotron VUV Photoionization Mass Spectroscopy

PubMed Central

Luo, Liangfeng; Tang, Xiaofeng; Wang, Wendong; Wang, Yu; Sun, Shaobo; Qi, Fei; Huang, Weixin

2013-01-01

Gas-phase methyl radicals have been long proposed as the key intermediate in catalytic oxidative coupling of methane, but the direct experimental evidence still lacks. Here, employing synchrotron VUV photoionization mass spectroscopy, we have directly observed the formation of gas-phase methyl radicals during oxidative coupling of methane catalyzed by Li/MgO catalysts. The concentration of gas-phase methyl radicals correlates well with the yield of ethylene and ethane products. These results lead to an enhanced fundamental understanding of oxidative coupling of methane that will facilitate the exploration of new catalysts with improved performance. PMID:23567985

Establishment and analysis of coupled dynamic model for dual-mass silicon micro-gyroscope

NASA Astrophysics Data System (ADS)

Wang, Zhanghui; Qiu, Anping; Shi, Qin; Zhang, Taoyuan

2017-12-01

This paper presents a coupled dynamic model for a dual-mass silicon micro-gyroscope (DMSG). It can quantitatively analyze the influence of left-right stiffness difference on the natural frequencies, modal matrix and modal coupling coefficient of the DMSG. The analytic results are verified by using the finite element method (FEM) simulation. The model shows that with the left-right stiffness difference of 1%, the modal coupling coefficient is 12% in the driving direction and 31% in the sensing direction. It also shows that in order to achieve good separation, the stiffness of base beam should be small enough in both the driving and sensing direction.

A coupled ice-ocean model of ice breakup and banding in the marginal ice zone

NASA Technical Reports Server (NTRS)

Smedstad, O. M.; Roed, L. P.

1985-01-01

A coupled ice-ocean numerical model for the marginal ice zone is considered. The model consists of a nonlinear sea ice model and a two-layer (reduced gravity) ocean model. The dependence of the upwelling response on wind stress direction is discussed. The results confirm earlier analytical work. It is shown that there exist directions for which there is no upwelling, while other directions give maximum upwelling in terms of the volume of uplifted water. The ice and ocean is coupled directly through the stress at the ice-ocean interface. An interesting consequence of the coupling is found in cases when the ice edge is almost stationary. In these cases the ice tends to break up a few tenths of kilometers inside of the ice edge.

Mechanochemical Modeling of Dynamic Microtubule Growth Involving Sheet-to-Tube Transition

PubMed Central

Ji, Xiang-Ying; Feng, Xi-Qiao

2011-01-01

Microtubule dynamics is largely influenced by nucleotide hydrolysis and the resultant tubulin configuration changes. The GTP cap model has been proposed to interpret the stabilizing mechanisms of microtubule growth from the view of hydrolysis effects. Besides, the growth of a microtubule involves the closure of a curved sheet at its growing end. The curvature conversion from the longitudinal direction to the circumferential direction also helps to stabilize the successive growth, and the curved sheet is referred to as the conformational cap. However, there still lacks theoretical investigation on the mechanical–chemical coupling growth process of microtubules. In this paper, we study the growth mechanisms of microtubules by using a coarse-grained molecular method. First, the closure process involving a sheet-to-tube transition is simulated. The results verify the stabilizing effect of the sheet structure and predict that the minimum conformational cap length that can stabilize the growth is two dimers. Then, we show that the conformational cap and the GTP cap can function independently and harmoniously, signifying the pivotal role of mechanical factors. Furthermore, based on our theoretical results, we describe a Tetris-like growth style of microtubules: the stochastic tubulin assembly is regulated by energy and harmonized with the seam zipping such that the sheet keeps a practically constant length during growth. PMID:22205994

Enterocyte-afferent nerve interactions in dietary fat sensing.

PubMed

Mansouri, A; Langhans, W

2014-09-01

The central nervous system (CNS) constantly monitors nutrient availability in the body and, in particular, in the gastrointestinal (GI) tract to regulate nutrient and energy homeostasis. Extrinsic parasympathetic and sympathetic nerves are crucial for CNS nutrient sensing in the GI tract. These extrinsic afferent nerves detect the nature and amount of nutrients present in the GI tract and relay the information to the brain, which controls energy intake and expenditure accordingly. Dietary fat and fatty acids are sensed through various direct and indirect mechanisms. These sensing processes involve the binding of fatty acids to specific G protein-coupled receptors expressed either on the afferent nerve fibres or on the surface of enteroendocrine cells that release gut peptides, which themselves can modulate afferent nerve activity through their cognate receptors or have endocrine effects directly on the brain. Further dietary fat sensing mechanisms that are related to enterocyte fat handling and metabolism involve the release of several possible chemical mediators such as fatty acid ethanolamides or apolipoprotein A-IV. We here present evidence for yet another mechanism that may be based on ketone bodies resulting from enterocyte oxidation of dietary fat-derived fatty acids. The presently available evidence suggests that sympathetic rather than vagal afferents are involved, but further experiments are necessary to critically examine this concept. © 2014 John Wiley & Sons Ltd.

Bimetallic catalysis for C–C and C–X coupling reactions

PubMed Central

Pye, Dominic R.

2017-01-01

Bimetallic catalysis represents an alternative paradigm for coupling chemistry that complements the more traditional single-site catalysis approach. In this perspective, recent advances in bimetallic systems for catalytic C–C and C–X coupling reactions are reviewed. Behavior which complements that of established single-site catalysts is highlighted. Two major reaction classes are covered. First, generation of catalytic amounts of organometallic species of e.g. Cu, Au, or Ni capable of transmetallation to a Pd co-catalyst (or other traditional cross-coupling catalyst) has allowed important new C–C coupling technologies to emerge. Second, catalytic transformations involving binuclear bond-breaking and/or bond-forming steps, in some cases involving metal–metal bonds, represent a frontier area for C–C and C–X coupling processes.

Acetylcholine Release in Prefrontal Cortex Promotes Gamma Oscillations and Theta-Gamma Coupling during Cue Detection.

PubMed

Howe, William M; Gritton, Howard J; Lusk, Nicholas A; Roberts, Erik A; Hetrick, Vaughn L; Berke, Joshua D; Sarter, Martin

2017-03-22

The capacity for using external cues to guide behavior ("cue detection") constitutes an essential aspect of attention and goal-directed behavior. The cortical cholinergic input system, via phasic increases in prefrontal acetylcholine release, plays an essential role in attention by mediating such cue detection. However, the relationship between cholinergic signaling during cue detection and neural activity dynamics in prefrontal networks remains unclear. Here we combined subsecond measures of cholinergic signaling, neurophysiological recordings, and cholinergic receptor blockade to delineate the cholinergic contributions to prefrontal oscillations during cue detection in rats. We first confirmed that detected cues evoke phasic acetylcholine release. These cholinergic signals were coincident with increased neuronal synchrony across several frequency bands and the emergence of theta-gamma coupling. Muscarinic and nicotinic cholinergic receptors both contributed specifically to gamma synchrony evoked by detected cues, but the effects of blocking the two receptor subtypes were dissociable. Blocking nicotinic receptors primarily attenuated high-gamma oscillations occurring during the earliest phases of the cue detection process, while muscarinic (M1) receptor activity was preferentially involved in the transition from high to low gamma power that followed and corresponded to the mobilization of networks involved in cue-guided decision making. Detected cues also promoted coupling between gamma and theta oscillations, and both nicotinic and muscarinic receptor activity contributed to this process. These results indicate that acetylcholine release coordinates neural oscillations during the process of cue detection. SIGNIFICANCE STATEMENT The capacity of learned cues to direct attention and guide responding ("cue detection") is a key component of goal-directed behavior. Rhythmic neural activity and increases in acetylcholine release in the prefrontal cortex contribute to this process; however, the relationship between these neuronal mechanisms is not well understood. Using a combination of in vivo neurochemistry, neurophysiology, and pharmacological methods, we demonstrate that cue-evoked acetylcholine release, through distinct actions at both nicotinic and muscarinic receptors, triggers a procession of neural oscillations that map onto the multiple stages of cue detection. Our data offer new insights into cholinergic function by revealing the temporally orchestrated changes in prefrontal network synchrony modulated by acetylcholine release during cue detection. Copyright © 2017 the authors 0270-6474/17/373215-16$15.00/0.

Gβ Regulates Coupling between Actin Oscillators for Cell Polarity and Directional Migration

PubMed Central

Cai, Huaqing; Sun, Yaohui; Huang, Chuan-Hsiang; Freyre, Mariel; Zhao, Min; Devreotes, Peter N.; Weiner, Orion D.

2016-01-01

For directional movement, eukaryotic cells depend on the proper organization of their actin cytoskeleton. This engine of motility is made up of highly dynamic nonequilibrium actin structures such as flashes, oscillations, and traveling waves. In Dictyostelium, oscillatory actin foci interact with signals such as Ras and phosphatidylinositol 3,4,5-trisphosphate (PIP3) to form protrusions. However, how signaling cues tame actin dynamics to produce a pseudopod and guide cellular motility is a critical open question in eukaryotic chemotaxis. Here, we demonstrate that the strength of coupling between individual actin oscillators controls cell polarization and directional movement. We implement an inducible sequestration system to inactivate the heterotrimeric G protein subunit Gβ and find that this acute perturbation triggers persistent, high-amplitude cortical oscillations of F-actin. Actin oscillators that are normally weakly coupled to one another in wild-type cells become strongly synchronized following acute inactivation of Gβ. This global coupling impairs sensing of internal cues during spontaneous polarization and sensing of external cues during directional motility. A simple mathematical model of coupled actin oscillators reveals the importance of appropriate coupling strength for chemotaxis: moderate coupling can increase sensitivity to noisy inputs. Taken together, our data suggest that Gβ regulates the strength of coupling between actin oscillators for efficient polarity and directional migration. As these observations are only possible following acute inhibition of Gβ and are masked by slow compensation in genetic knockouts, our work also shows that acute loss-of-function approaches can complement and extend the reach of classical genetics in Dictyostelium and likely other systems as well. PMID:26890004

Evidence by site-directed mutagenesis that arginine 203 of thermolysin and arginine 717 of neprilysin (neutral endopeptidase) play equivalent critical roles in substrate hydrolysis and inhibitor binding.

PubMed

Marie-Claire, C; Ruffet, E; Antonczak, S; Beaumont, A; O'Donohue, M; Roques, B P; Fournié-Zaluski, M C

1997-11-11

Neprilysin (neutral endopeptidase-24.11, EC 3.4.24.11) is a mammalian zinc-endopeptidase involved in the degradation of biologically active peptides. Although no atomic structure is available for this enzyme, site-directed mutagenesis studies have shown that its active site resembles closely that of the bacterial zinc-endopeptidase, thermolysin (EC 3.4.24.27). One active site residue of thermolysin, Arg-203, is involved in inhibitor binding by forming hydrogen bonds with the carbonyl group of a residue in the P1 position and also participates in a hydrogen bond network involving Asp-170. Sequence alignment data shows that Arg-717 of neprilysin could play a similar role to Arg-203 of thermolysin. This was investigated by site-directed mutagenesis with Arg-203 of thermolysin and Arg-717 of neprilysin being replaced by methionine residues. This led, in both cases, to decreases in kcat/Km values, of 122-fold for neprilysin and 2300-fold for thermolysin, essentially due to changes in kcat. The Ki values of several inhibitors were also increased for the mutated enzymes. In addition, the replacement of Asp-170 of thermolysin by Ala residue resulted in a decrease in kcat/Km of 220-fold. The results, coupled with a molecular modeling study, suggest that Arg-717 of neprilysin corresponds to Arg-203 of thermolysin and that in both enzymes a hydrogen bond network exists, involving His-142, Asp-170, and Arg-203 in thermolysin and His-583, Asp-650, and Arg-717 in neprilysin, which is crucial for hydrolytic activity.

Direction of Coupling from Phases of Interacting Oscillators: A Permutation Information Approach

NASA Astrophysics Data System (ADS)

Bahraminasab, A.; Ghasemi, F.; Stefanovska, A.; McClintock, P. V. E.; Kantz, H.

2008-02-01

We introduce a directionality index for a time series based on a comparison of neighboring values. It can distinguish unidirectional from bidirectional coupling, as well as reveal and quantify asymmetry in bidirectional coupling. It is tested on a numerical model of coupled van der Pol oscillators, and applied to cardiorespiratory data from healthy subjects. There is no need for preprocessing and fine-tuning the parameters, which makes the method very simple, computationally fast and robust.

Male circumcision for HIV prevention: female risk compensatory behaviour in South Africa.

PubMed

Greevy, Clare; King, Rebecca; Haffejee, Firoza

2018-05-20

South Africa promotes male circumcision (MC) as an HIV prevention method and implemented a national plan to scale-up MC in the country from 2012 to 2016. Literature has suggested that female risk compensatory behaviours (RCBs) are occurring in countries where these programmes have been implemented. Behaviours such as decreased condom use, concurrent sexual partners and sexual activity during the circumcision wound-healing period have the potential to jeopardise the campaigns' objectives. Literature has shown that directly providing women with MC information results in correct knowledge however, previous studies have not directly sought women's views and ideas on engagement with the information. This study aims to identify and explore female RCBs in relation to MC campaigns in South Africa, and to identify interventions that would result in greater female involvement in the campaigns. Snowball sampling was used to conduct twelve qualitative vignette-facilitated semi-structured interviews with women residing in a municipal housing estate in Durban, Kwa-Zulu Natal, South Africa. Interviews were audio-recorded, verbatim transcribed and analysed using framework analysis. MC knowledge and understanding varied, with some participants mistaking MC as direct HIV protection for females. Despite a lack in knowledge, the majority of women did not report signs of RCBs. Even with a lack of evidence of RCBs, misinterpretation of the MC protective effect has the potential to lead to RCBs; a concept acknowledged in the literature. Several women expressed that MC campaigns are directed to males only and expressed a keenness to be more involved. Suggested interventions include couple counselling and female information sessions in community clinics. Exploring women's attitude towards involvement in MC campaigns fills in a research knowledge gap that is important to international health, as women have a vital role to play in reducing the transmission of HIV.

Kinematic control of walking.

PubMed

Lacquaniti, F; Ivanenko, Y P; Zago, M

2002-10-01

The planar law of inter-segmental co-ordination we described may emerge from the coupling of neural oscillators between each other and with limb mechanical oscillators. Muscle contraction intervenes at variable times to re-excite the intrinsic oscillations of the system when energy is lost. The hypothesis that a law of coordinative control results from a minimal active tuning of the passive inertial and viscoelastic coupling among limb segments is congruent with the idea that movement has evolved according to minimum energy criteria (1, 8). It is known that multi-segment motion of mammals locomotion is controlled by a network of coupled oscillators (CPGs, see 18, 33, 37). Flexible combination of unit oscillators gives rise to different forms of locomotion. Inter-oscillator coupling can be modified by changing the synaptic strength (or polarity) of the relative spinal connections. As a result, unit oscillators can be coupled in phase, out of phase, or with a variable phase, giving rise to different behaviors, such as speed increments or reversal of gait direction (from forward to backward). Supra-spinal centers may drive or modulate functional sets of coordinating interneurons to generate different walking modes (or gaits). Although it is often assumed that CPGs control patterns of muscle activity, an equally plausible hypothesis is that they control patterns of limb segment motion instead (22). According to this kinematic view, each unit oscillator would directly control a limb segment, alternately generating forward and backward oscillations of the segment. Inter-segmental coordination would be achieved by coupling unit oscillators with a variable phase. Inter-segmental kinematic phase plays the role of global control variable previously postulated for the network of central oscillators. In fact, inter-segmental phase shifts systematically with increasing speed both in man (4) and cat (38). Because this phase-shift is correlated with the net mechanical power output over a gait cycle (3, 4), phase control could be used for limiting the overall energy expenditure with increasing speed (22). Adaptation to different walking conditions, such as changes in body posture, body weight unloading and backward walk, also involves inter-segmental phase tuning, as does the maturation of limb kinematics in toddlers.

New frontiers in couple-based interventions in cancer care: refining the prescription for spousal communication.

PubMed

Badr, Hoda

2017-02-01

The diagnosis and treatment of cancer is a life-altering experience that signals profound changes in a person's life. However, most people do not experience cancer in isolation or cope alone. Despite the fact that partners (i.e. spouses, significant others) provide emotional support and play a critical role in caregiving, cancer exacts a heavy toll on them and challenges their relationship with the patient by altering established communication patterns and roles. In recognition of this, a burgeoning literature involving couple-based interventions to improve patient and partner quality of life and adaptation has emerged. However, questions remain regarding how we can improve these interventions to exact greater impact on patient and partner outcomes. A narrative review of the literature on couples' communication processes in cancer was conducted in order to describe knowledge gaps and directions for future research. Most couple-based interventions have included a communication skills training component because communication is an important process through which couples make sense of cancer, engage in social support, negotiate role changes and coordinate coping responses. However, scholars still know very little about what they should instruct couples to talk about, how often they should talk and when talking (or not talking) is beneficial (and for whom - the patient, partner, or both). In order push this field forward, we need to develop a more nuanced view of couples' communication that acknowledges that there are multiple ways to talk, different aspects of the cancer experience to talk about, and preexisting communication patterns and preferences for different couples that may influence the utility of talk. Interventions that replace the unilateral and generic prescription to talk openly about cancer with targeted questions that prompt reflection on couples' unique strengths, preexisting communication patterns and support resources may thus help bolster the impact of couple-based interventions on patient and partner quality of life.

Indirect consequences of exciplex states on the phosphorescence lifetime of phenazine-based 1,2,3-triazole luminescent probes.

PubMed

Costa, Bárbara B A; Jardim, Guilherme A M; Santos, Paloma L; Calado, Hállen D R; Monkman, Andrew P; Dias, Fernando B; da Silva Júnior, Eufrânio N; Cury, Luiz A

2017-02-01

The optical properties of phenazine derivative probe solutions involving intersystem crossing from singlet to triplet states were investigated by time resolved spectroscopy. The room temperature phosphorescence emission presented different time responses when Cd 2+ ions were bound to the probe chemical structure. The complex exciplex formation observed to occur in this case was not directly responsible for the change in the phosphorescence lifetime. This was more influenced by the new molecular conformation and modified spin-orbit coupling imposed by the binding of the Cd 2+ ions to the phenazine molecules.

CuI/Pd0 cooperative dual catalysis: tunable stereoselective construction of tetra-substituted alkenes.

PubMed

Vercruysse, Sébastien; Cornelissen, Loïc; Nahra, Fady; Collard, Laurent; Riant, Olivier

2014-02-10

This paper describes a tunable and stereoselective dual catalytic system that uses copper and palladium reagents. This cooperative silylcupration and palladium-catalyzed allylation readily affords trisubstituted alkenylsilanes. Fine-tuning the reaction conditions allows selective access to one stereoisomer over the other. This new methodology tolerates different substituents on both coupling partners with high levels of stereoselectivity. The one-pot reaction involving a Cu(I)/Pd(0) cooperative dual catalyst directly addresses the need to develop more time-efficient and less-wasteful synthetic pathways. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Stem cells in retinal regeneration: past, present and future.

PubMed

Ramsden, Conor M; Powner, Michael B; Carr, Amanda-Jayne F; Smart, Matthew J K; da Cruz, Lyndon; Coffey, Peter J

2013-06-01

Stem cell therapy for retinal disease is under way, and several clinical trials are currently recruiting. These trials use human embryonic, foetal and umbilical cord tissue-derived stem cells and bone marrow-derived stem cells to treat visual disorders such as age-related macular degeneration, Stargardt's disease and retinitis pigmentosa. Over a decade of analysing the developmental cues involved in retinal generation and stem cell biology, coupled with extensive surgical research, have yielded differing cellular approaches to tackle these retinopathies. Here, we review these various stem cell-based approaches for treating retinal diseases and discuss future directions and challenges for the field.

Theory of agent-based market models with controlled levels of greed and anxiety

NASA Astrophysics Data System (ADS)

Papadopoulos, P.; Coolen, A. C. C.

2010-01-01

We use generating functional analysis to study minority-game-type market models with generalized strategy valuation updates that control the psychology of agents' actions. The agents' choice between trend-following and contrarian trading, and their vigor in each, depends on the overall state of the market. Even in 'fake history' models, the theory now involves an effective overall bid process (coupled to the effective agent process) which can exhibit profound remanence effects and new phase transitions. For some models the bid process can be solved directly, others require Maxwell-construction-type approximations.

Copper(II)-catalyzed amidations of alkynyl bromides as a general synthesis of ynamides and Z-enamides. An intramolecular amidation for the synthesis of macrocyclic ynamides.

PubMed

Zhang, Xuejun; Zhang, Yanshi; Huang, Jian; Hsung, Richard P; Kurtz, Kimberly C M; Oppenheimer, Jossian; Petersen, Matthew E; Sagamanova, Irina K; Shen, Lichun; Tracey, Michael R

2006-05-26

A general and efficient method for the coupling of a wide range of amides with alkynyl bromides is described here. This novel amidation reaction involves a catalytic protocol using copper(II) sulfate-pentahydrate and 1,10-phenanthroline to direct the sp-C-N bond formation, leading to a structurally diverse array of ynamides including macrocyclic ynamides via an intramolecular amidation. Given the surging interest in ynamide chemistry, this atom economical synthesis of ynamides should invoke further attention from the synthetic organic community.

Benefits of detailed models of muscle activation and mechanics

NASA Technical Reports Server (NTRS)

Lehman, S. L.; Stark, L.

1981-01-01

Recent biophysical and physiological studies identified some of the detailed mechanisms involved in excitation-contraction coupling, muscle contraction, and deactivation. Mathematical models incorporating these mechanisms allow independent estimates of key parameters, direct interplay between basic muscle research and the study of motor control, and realistic model behaviors, some of which are not accessible to previous, simpler, models. The existence of previously unmodeled behaviors has important implications for strategies of motor control and identification of neural signals. New developments in the analysis of differential equations make the more detailed models feasible for simulation in realistic experimental situations.

Inverse dynamic substructuring using the direct hybrid assembly in the frequency domain

NASA Astrophysics Data System (ADS)

D'Ambrogio, Walter; Fregolent, Annalisa

2014-04-01

The paper deals with the identification of the dynamic behaviour of a structural subsystem, starting from the known dynamic behaviour of both the coupled system and the remaining part of the structural system (residual subsystem). This topic is also known as decoupling problem, subsystem subtraction or inverse dynamic substructuring. Whenever it is necessary to combine numerical models (e.g. FEM) and test models (e.g. FRFs), one speaks of experimental dynamic substructuring. Substructure decoupling techniques can be classified as inverse coupling or direct decoupling techniques. In inverse coupling, the equations describing the coupling problem are rearranged to isolate the unknown substructure instead of the coupled structure. On the contrary, direct decoupling consists in adding to the coupled system a fictitious subsystem that is the negative of the residual subsystem. Starting from a reduced version of the 3-field formulation (dynamic equilibrium using FRFs, compatibility and equilibrium of interface forces), a direct hybrid assembly is developed by requiring that both compatibility and equilibrium conditions are satisfied exactly, either at coupling DoFs only, or at additional internal DoFs of the residual subsystem. Equilibrium and compatibility DoFs might not be the same: this generates the so-called non-collocated approach. The technique is applied using experimental data from an assembled system made by a plate and a rigid mass.

Direct handling of equality constraints in multilevel optimization

NASA Technical Reports Server (NTRS)

Renaud, John E.; Gabriele, Gary A.

1990-01-01

In recent years there have been several hierarchic multilevel optimization algorithms proposed and implemented in design studies. Equality constraints are often imposed between levels in these multilevel optimizations to maintain system and subsystem variable continuity. Equality constraints of this nature will be referred to as coupling equality constraints. In many implementation studies these coupling equality constraints have been handled indirectly. This indirect handling has been accomplished using the coupling equality constraints' explicit functional relations to eliminate design variables (generally at the subsystem level), with the resulting optimization taking place in a reduced design space. In one multilevel optimization study where the coupling equality constraints were handled directly, the researchers encountered numerical difficulties which prevented their multilevel optimization from reaching the same minimum found in conventional single level solutions. The researchers did not explain the exact nature of the numerical difficulties other than to associate them with the direct handling of the coupling equality constraints. The coupling equality constraints are handled directly, by employing the Generalized Reduced Gradient (GRG) method as the optimizer within a multilevel linear decomposition scheme based on the Sobieski hierarchic algorithm. Two engineering design examples are solved using this approach. The results show that the direct handling of coupling equality constraints in a multilevel optimization does not introduce any problems when the GRG method is employed as the internal optimizer. The optimums achieved are comparable to those achieved in single level solutions and in multilevel studies where the equality constraints have been handled indirectly.

Direction selective structural-acoustic coupled radiator

NASA Astrophysics Data System (ADS)

Seo, Hee-Seon; Kim, Yang-Hann

2005-04-01

This paper presents a method of designing a structural-acoustic coupled radiator that can emit sound in the desired direction. The structural-acoustic coupled system is consisted of acoustic spaces and wall. The wall composes two plates and an opening, and the wall separates one space that is highly reverberant and the other that is unbounded without any reflection. An equation is developed that predicts energy distribution and energy flow in the two spaces separated by the wall, and its computational examples are presented including near field acoustic characteristics. To design the directional coupled radiator, Pareto optimization method is adapted. An objective is selected to maximize radiation power on a main axis and minimize a side lobe level and a subjective is selected direction of the main axis and dimensions of the walls geometry. Pressure and intensity distribution of the designed radiator is also presented.

Parallel Plate System for Collecting Data Used to Determine Viscosity

NASA Technical Reports Server (NTRS)

Ethridge, Edwin C. (Inventor); Kaukler, William (Inventor)

2013-01-01

A parallel-plate system collects data used to determine viscosity. A first plate is coupled to a translator so that the first plate can be moved along a first direction. A second plate has a pendulum device coupled thereto such that the second plate is suspended above and parallel to the first plate. The pendulum device constrains movement of the second plate to a second direction that is aligned with the first direction and is substantially parallel thereto. A force measuring device is coupled to the second plate for measuring force along the second direction caused by movement of the second plate.

High-accuracy direct ZT and intrinsic properties measurement of thermoelectric couple devices.

PubMed

Kraemer, D; Chen, G

2014-04-01

Advances in thermoelectric materials in recent years have led to significant improvements in thermoelectric device performance and thus, give rise to many new potential applications. In order to optimize a thermoelectric device for specific applications and to accurately predict its performance ideally the material's figure of merit ZT as well as the individual intrinsic properties (Seebeck coefficient, electrical resistivity, and thermal conductivity) should be known with high accuracy. For that matter, we developed two experimental methods in which the first directly obtains the ZT and the second directly measures the individual intrinsic leg properties of the same p/n-type thermoelectric couple device. This has the advantage that all material properties are measured in the same sample direction after the thermoelectric legs have been mounted in the final device. Therefore, possible effects from crystal anisotropy and from the device fabrication process are accounted for. The Seebeck coefficients, electrical resistivities, and thermal conductivities are measured with differential methods to minimize measurement uncertainties to below 3%. The thermoelectric couple ZT is directly measured with a differential Harman method which is in excellent agreement with the calculated ZT from the individual leg properties. The errors in both the directly measured and calculated thermoelectric couple ZT are below 5% which is significantly lower than typical uncertainties using commercial methods. Thus, the developed technique is ideal for characterizing assembled couple devices and individual thermoelectric materials and enables accurate device optimization and performance predictions. We demonstrate the methods by measuring a p/n-type thermoelectric couple device assembled from commercial bulk thermoelectric Bi2Te3 elements in the temperature range of 30 °C-150 °C and discuss the performance of the couple thermoelectric generator in terms of its efficiency and materials' self-compatibility.

Enantioselective Desymmetrization via Carbonyl-Directed Catalytic Asymmetric Hydroboration and Suzuki-Miyaura Cross-Coupling

PubMed Central

Hoang, Gia L.; Yang, Zhao-Di; Smith, Sean M.; Pal, Rhitankar; Miska, Judy L.; Pérez, Damaris E.; Pelter, Libbie S. W.; Zeng, Xiao Cheng; Takacs, James M.

2015-01-01

The rhodium-catalyzed enantioselective desymmetrization of symmetric γ,δ–unsaturated amides via carbonyl-directed catalytic asymmetric hydroboration (directed CAHB) affords chiral secondary organoboronates with up to 98% ee. The chiral γ–borylated products undergo palladium-catalyzed Suzuki-Miyaura cross-coupling via the trifluoroborate salt with stereoretention. PMID:25642639

DRIFT COMPENSATED DIRECT COUPLED AMPLIFIER

DOEpatents

Windsor, A.A.

1959-05-01

An improved direct-coupled amplifier having zerolevel drift correction is described. The need for an auxiliary corrective-potential amplifier is eliminated thereby giving protection against overload saturation of the zero- level drift correcting circuit. (T.R.H.)

Directional coupler based on an elliptic cylindrical nanowire hybrid plasmonic waveguide.

PubMed

Zeng, Dezheng; Zhang, Li; Xiong, Qiulin; Ma, Junxian

2018-06-01

We present what we believe is a novel directional coupler based on an elliptic cylindrical nanowire hybrid plasmonic waveguide. Using the finite element method, the electric field distributions of y-polarized symmetric and antisymmetric modes of the coupler are compared, and the coupling and transmission characteristics are analyzed; then the optimized separation distance between the two parallel waveguides, 100 nm, is obtained. This optimized architecture fits in the weak coupling regime. Furthermore, the energy transfer is studied, and the performances of the directional coupler are evaluated, including excess loss, coupling degree, and directionality. The results show that when the separation distance is set to 100 nm, the coupling length reaches the shorter value of 1.646 μm, and the propagation loss is as low as 0.076 dB/μm, and the maximum energy transfer can reach 80%. The proposed directional coupler features good energy confinement, ultracompact and low propagation loss, which has potential application in dense photonic-integrated circuits and other photonic devices.

Phase dynamics of coupled oscillators reconstructed from data

NASA Astrophysics Data System (ADS)

Rosenblum, Michael; Kralemann, Bjoern; Pikovsky, Arkady

2013-03-01

We present a technique for invariant reconstruction of the phase dynamics equations for coupled oscillators from data. The invariant description is achieved by means of a transformation of phase estimates (protophases) obtained from general scalar observables to genuine phases. Staring from the bivariate data, we obtain the coupling functions in terms of these phases. We discuss the importance of the protophase-to-phase transformation for characterization of strength and directionality of interaction. To illustrate the technique we analyse the cardio-respiratory interaction on healthy humans. Our invariant approach is confirmed by high similarity of the coupling functions obtained from different observables of the cardiac system. Next, we generalize the technique to cover the case of small networks of coupled periodic units. We use the partial norms of the reconstructed coupling functions to quantify directed coupling between the oscillators. We illustrate the method by different network motifs for three coupled oscillators. We also discuss nonlinear effects in coupling.

α-Unsubstituted Pyrroles by NHC-Catalyzed Three-Component Coupling: Direct Synthesis of a Versatile Atorvastatin Derivative.

PubMed

Fleige, Mirco; Glorius, Frank

2017-08-10

A practical one-pot cascade reaction protocol provides direct access to valuable 1,2,4-trisubstituted pyrroles. The process involves an N-heterocyclic carbene (NHC)-catalyzed Stetter-type hydroformylation using glycolaldehyde dimer as a novel C1 building-block, followed by a Paal-Knorr condensation with primary amines. The reaction makes use of simple and commercially available starting-materials and catalyst, an important feature regarding applicability and utility. Low catalyst loading under mild reaction conditions afforded a variety of 1,2,4-substituted pyrroles in a transition-metal-free reaction with high step economy and good yields. This methodology is applied in the synthesis of a versatile Atorvastatin precursor, in which a variety of modifications at the pyrrole core structure are possible. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Data-driven reconstruction of directed networks

NASA Astrophysics Data System (ADS)

Hempel, Sabrina; Koseska, Aneta; Nikoloski, Zoran

2013-06-01

We investigate the properties of a recently introduced asymmetric association measure, called inner composition alignment (IOTA), aimed at inferring regulatory links (couplings). We show that the measure can be used to determine the direction of coupling, detect superfluous links, and to account for autoregulation. In addition, the measure can be extended to infer the type of regulation (positive or negative). The capabilities of IOTA to correctly infer couplings together with their directionality are compared against Kendall's rank correlation for time series of different lengths, particularly focussing on biological examples. We demonstrate that an extended version of the measure, bidirectional inner composition alignment (biIOTA), increases the accuracy of the network reconstruction for short time series. Finally, we discuss the applicability of the measure to infer couplings in chaotic systems.

Examination of the skin barrier repair/wound healing process using a living skin equivalent model and matrix-assisted laser desorption-ionization-mass spectrometry imaging.

PubMed

Lewis, E E L; Barrett, M R T; Freeman-Parry, L; Bojar, R A; Clench, M R

2018-04-01

Examination of the skin barrier repair/wound healing process using a living skin equivalent (LSE) model and matrix-assisted laser desorption/ionization-mass spectrometry imaging (MALDI-MSI) to identify lipids directly involved as potential biomarkers. These biomarkers may be used to determine whether an in vivo wound is going to heal for example if infected. An in vitro LSE model was wounded with a scalpel blade and assessed at day 4 post-wounding by histology and MALDI-MSI. Samples were sectioned at wound site and were either formalin-fixed paraffin-embedded (FFPE) for histology or snapped frozen (FF) for MSI analysis. The combination of using an in vitro wounded skin model with MSI allowed the identification of lipids involved in the skin barrier repair/wound healing process. The technique was able to highlight lipids directly in the wound site and distinguish differences in lipid distribution between the epidermis and wound site. This novel method of coupling an in vitro LSE with MSI allowed in-depth molecular analysis of the skin barrier repair/wound healing process. The technique allowed the identification of lipids directly involved in the skin barrier repair/wound healing process, indicating these biomarkers may be potentially be used within the clinic. These biomarkers will help to determine, which stage of the skin barrier repair/wound healing process the wound is in to provide the best treatment. © 2018 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

Higher-Order Theory for Functionally Graded Materials

NASA Technical Reports Server (NTRS)

Aboudi, Jacob; Pindera, Marek-Jerzy; Arnold, Steven M.

1999-01-01

This paper presents the full generalization of the Cartesian coordinate-based higher-order theory for functionally graded materials developed by the authors during the past several years. This theory circumvents the problematic use of the standard micromechanical approach, based on the concept of a representative volume element, commonly employed in the analysis of functionally graded composites by explicitly coupling the local (microstructural) and global (macrostructural) responses. The theoretical framework is based on volumetric averaging of the various field quantities, together with imposition of boundary and interfacial conditions in an average sense between the subvolumes used to characterize the composite's functionally graded microstructure. The generalization outlined herein involves extension of the theoretical framework to enable the analysis of materials characterized by spatially variable microstructures in three directions. Specialization of the generalized theoretical framework to previously published versions of the higher-order theory for materials functionally graded in one and two directions is demonstrated. In the applications part of the paper we summarize the major findings obtained with the one-directional and two-directional versions of the higher-order theory. The results illustrate both the fundamental issues related to the influence of microstructure on microscopic and macroscopic quantities governing the response of composites and the technologically important applications. A major issue addressed herein is the applicability of the classical homogenization schemes in the analysis of functionally graded materials. The technologically important applications illustrate the utility of functionally graded microstructures in tailoring the response of structural components in a variety of applications involving uniform and gradient thermomechanical loading.

Investigating the Direct Meltwater Effect in Terrestrial Oxygen-Isotope Paleoclimate Records Using an Isotope-Enabled Earth System Model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhu, Jiang; Liu, Zhengyu; Brady, Esther C.

Variations in terrestrial oxygen-isotope reconstructions from ice cores and speleothems have been primarily attributed to climatic changes of surface air temperature, precipitation amount, or atmospheric circulation. In this work, we demonstrate with the fully coupled isotope-enabled Community Earth System Model an additional process contributing to the oxygen-isotope variations during glacial meltwater events. This process, termed “the direct meltwater effect,” involves propagating large amounts of isotopically depleted meltwater throughout the hydrological cycle and is independent of climatic changes. We find that the direct meltwater effect can make up 15–35% of the δ 18O signals in precipitation over Greenland and eastern Brazilmore » for large freshwater forcings (0.25–0.50 sverdrup (10 6 m 3/s)). Model simulations further demonstrate that the direct meltwater effect increases with the magnitude and duration of the freshwater forcing and is sensitive to both the location and shape of the meltwater. These new modeling results have important implications for past climate interpretations of δ 18O.« less

Investigating the Direct Meltwater Effect in Terrestrial Oxygen-Isotope Paleoclimate Records Using an Isotope-Enabled Earth System Model

DOE PAGES

Zhu, Jiang; Liu, Zhengyu; Brady, Esther C.; ...

2017-12-28

Variations in terrestrial oxygen-isotope reconstructions from ice cores and speleothems have been primarily attributed to climatic changes of surface air temperature, precipitation amount, or atmospheric circulation. In this work, we demonstrate with the fully coupled isotope-enabled Community Earth System Model an additional process contributing to the oxygen-isotope variations during glacial meltwater events. This process, termed “the direct meltwater effect,” involves propagating large amounts of isotopically depleted meltwater throughout the hydrological cycle and is independent of climatic changes. We find that the direct meltwater effect can make up 15–35% of the δ 18O signals in precipitation over Greenland and eastern Brazilmore » for large freshwater forcings (0.25–0.50 sverdrup (10 6 m 3/s)). Model simulations further demonstrate that the direct meltwater effect increases with the magnitude and duration of the freshwater forcing and is sensitive to both the location and shape of the meltwater. These new modeling results have important implications for past climate interpretations of δ 18O.« less

Simplified derivation of the gravitational wave stress tensor from the linearized Einstein field equations.

PubMed

Balbus, Steven A

2016-10-18

A conserved stress energy tensor for weak field gravitational waves propagating in vacuum is derived directly from the linearized general relativistic wave equation alone, for an arbitrary gauge. In any harmonic gauge, the form of the tensor leads directly to the classical expression for the outgoing wave energy. The method described here, however, is a much simpler, shorter, and more physically motivated approach than is the customary procedure, which involves a lengthy and cumbersome second-order (in wave-amplitude) calculation starting with the Einstein tensor. Our method has the added advantage of exhibiting the direct coupling between the outgoing wave energy flux and the work done by the gravitational field on the sources. For nonharmonic gauges, the directly derived wave stress tensor has an apparent index asymmetry. This coordinate artifact may be straightforwardly removed, and the symmetrized (still gauge-invariant) tensor then takes on its widely used form. Angular momentum conservation follows immediately. For any harmonic gauge, however, the stress tensor found is manifestly symmetric from the start, and its derivation depends, in its entirety, on the structure of the linearized wave equation.

From lignin to cycloparaffins and aromatics: directional synthesis of jet and diesel fuel range biofuels using biomass.

PubMed

Bi, Peiyan; Wang, Jicong; Zhang, Yajing; Jiang, Peiwen; Wu, Xiaoping; Liu, Junxu; Xue, He; Wang, Tiejun; Li, Quanxin

2015-05-01

The continual growth in commercial aviation fuels and more strict environmental legislations have led to immense interest in developing green aviation fuels from biomass. This paper demonstrated a controllable transformation of lignin into jet and diesel fuel range hydrocarbons, involving directional production of C8-C15 aromatics by the catalytic depolymerization of lignin into C6-C8 low carbon aromatic monomers coupled with the alkylation of aromatics, and the directional production of C8-C15 cycloparaffins by the hydrogenation of aromatics. The key step, the production of the desired C8-C15 aromatics with the selectivity up to 94.3%, was achieved by the low temperature alkylation reactions of the lignin-derived monomers using ionic liquid. The synthetic biofuels basically met the main technical requirements of conventional jet fuels. The transformation potentially provides a useful way for the development of cycloparaffinic and aromatic components in jet fuels using renewable lignocellulose biomass. Copyright © 2015. Published by Elsevier Ltd.

Sequence-dependent base pair stepping dynamics in XPD helicase unwinding

PubMed Central

Qi, Zhi; Pugh, Robert A; Spies, Maria; Chemla, Yann R

2013-01-01

Helicases couple the chemical energy of ATP hydrolysis to directional translocation along nucleic acids and transient duplex separation. Understanding helicase mechanism requires that the basic physicochemical process of base pair separation be understood. This necessitates monitoring helicase activity directly, at high spatio-temporal resolution. Using optical tweezers with single base pair (bp) resolution, we analyzed DNA unwinding by XPD helicase, a Superfamily 2 (SF2) DNA helicase involved in DNA repair and transcription initiation. We show that monomeric XPD unwinds duplex DNA in 1-bp steps, yet exhibits frequent backsteps and undergoes conformational transitions manifested in 5-bp backward and forward steps. Quantifying the sequence dependence of XPD stepping dynamics with near base pair resolution, we provide the strongest and most direct evidence thus far that forward, single-base pair stepping of a helicase utilizes the spontaneous opening of the duplex. The proposed unwinding mechanism may be a universal feature of DNA helicases that move along DNA phosphodiester backbones. DOI: http://dx.doi.org/10.7554/eLife.00334.001 PMID:23741615

Discriminating cascading processes in nonlinear optics: A QED analysis based on their molecular and geometric origin

NASA Astrophysics Data System (ADS)

Bennett, Kochise; Chernyak, Vladimir Y.; Mukamel, Shaul

2017-03-01

The nonlinear optical response of a system of molecules often contains contributions whereby the products of lower-order processes in two separate molecules give signals that appear on top of a genuine direct higher-order process with a single molecule. These many-body contributions are known as cascading and complicate the interpretation of multidimensional stimulated Raman and other nonlinear signals. In a quantum electrodynamic treatment, these cascading processes arise from second-order expansion in the molecular coupling to vacuum modes of the radiation field, i.e., single-photon exchange between molecules, which also gives rise to other collective effects. We predict the relative phase of the direct and cascading nonlinear signals and its dependence on the microscopic dynamics as well as the sample geometry. This phase may be used to identify experimental conditions for distinguishing the direct and cascading signals by their phase. Higher-order cascading processes involving the exchange of several photons between more than two molecules are discussed.

Directed and persistent movement arises from mechanochemistry of the ParA/ParB system.

PubMed

Hu, Longhua; Vecchiarelli, Anthony G; Mizuuchi, Kiyoshi; Neuman, Keir C; Liu, Jian

2015-12-22

The segregation of DNA before cell division is essential for faithful genetic inheritance. In many bacteria, segregation of low-copy number plasmids involves an active partition system composed of a nonspecific DNA-binding ATPase, ParA, and its stimulator protein ParB. The ParA/ParB system drives directed and persistent movement of DNA cargo both in vivo and in vitro. Filament-based models akin to actin/microtubule-driven motility were proposed for plasmid segregation mediated by ParA. Recent experiments challenge this view and suggest that ParA/ParB system motility is driven by a diffusion ratchet mechanism in which ParB-coated plasmid both creates and follows a ParA gradient on the nucleoid surface. However, the detailed mechanism of ParA/ParB-mediated directed and persistent movement remains unknown. Here, we develop a theoretical model describing ParA/ParB-mediated motility. We show that the ParA/ParB system can work as a Brownian ratchet, which effectively couples the ATPase-dependent cycling of ParA-nucleoid affinity to the motion of the ParB-bound cargo. Paradoxically, this resulting processive motion relies on quenching diffusive plasmid motion through a large number of transient ParA/ParB-mediated tethers to the nucleoid surface. Our work thus sheds light on an emergent phenomenon in which nonmotor proteins work collectively via mechanochemical coupling to propel cargos-an ingenious solution shaped by evolution to cope with the lack of processive motor proteins in bacteria.

Modern separation techniques coupled to high performance mass spectrometry for glycolipid analysis.

PubMed

Sarbu, Mirela; Zamfir, Alina Diana

2018-01-21

Glycolipids (GLs), involved in biological processes and pathologies, such as viral, neurodegenerative and oncogenic transformations are in the focus of research related to method development for structural analysis. This review highlights modern separation techniques coupled to mass spectrometry (MS) for the investigation of GLs from various biological matrices. First section is dedicated to methods, which, although provide the separation in a non-liquid phase, are able to supply important data on the composition of complex mixtures. While classical thin layer chromatography (TLC) is useful for MS analyses of the fractionated samples, ultramodern ion mobility (IMS) characterized by high reproducibility facilitates to discover minor species and to apply low sample amounts, in addition to providing conformational separation with isomer discrimination. Second section highlights the advantages, applications and limitations of liquid-based separation techniques such as high performance liquid chromatography (HPLC) and hydrophilic interaction liquid chromatography (HILIC) in direct or indirect coupling to MS for glycolipidomics surveys. The on- and off-line capillary electrophoresis (CE) MS, offering a remarkable separation efficiency of GLs is also presented and critically assessed from the technical and application perspective in the final part of the review. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

[The other side of the ART, or when the desire takes shape].

PubMed

Vacher Vitasse, C; Rouget, K; Hocké, C

2012-09-01

To study unconscious factors involved with the occurrence of spontaneous pregnancies in Assisted Reproductive Technologies process (ART). We wrote to 519 couples having received the benefit of an ART process in the years 2005-2007 in the center of ART of the CHU of Bordeaux. In the mail, they were asked whether a spontaneous pregnancy had occurred during the process and a psychoanalytical orientation talk was suggested to them. Among 214 answers, 28 couples have declared a spontaneous pregnancy (so 13.1%). Twenty-six couples have been interviewed, 19 resulting from the questionnaire and seven registered in 2008 and having announced by their own the occurrence of a spontaneous pregnancy. Subjective factors directing the occurrence of a spontaneous pregnancy are found up to a significant degree. They are classified and studied by headings. Each heading is confronted with the data of the psychoanalytical literature. We find a correlation between the elements collected in the talks and those of the literature. The conclusion is in favor of unconscious factors playing a predominant part in the occurrence of spontaneous pregnancies for the unfertile subjects. Copyright © 2011 Elsevier Masson SAS. All rights reserved.

Flavor from the electroweak scale

DOE PAGES

Bauer, Martin; Carena, Marcela; Gemmler, Katrin

2015-11-04

We discuss the possibility that flavor hierarchies arise from the electroweak scale in a two Higgs doublet model, in which the two Higgs doublets jointly act as the flavon. Quark masses and mixing angles are explained by effective Yukawa couplings, generated by higher dimensional operators involving quarks and Higgs doublets. Modified Higgs couplings yield important effects on the production cross sections and decay rates of the light Standard Model like Higgs. In addition, flavor changing neutral currents arise at tree-level and lead to strong constraints from meson-antimeson mixing. Remarkably, flavor constraints turn out to prefer a region in parameter spacemore » that is in excellent agreement with the one preferred by recent Higgs precision measurements at the Large Hadron Collider (LHC). Direct searches for extra scalars at the LHC lead to further constraints. Precise predictions for the production and decay modes of the additional Higgs bosons are derived, and we present benchmark scenarios for searches at the LHC Run II. As a result, flavor breaking at the electroweak scale as well as strong coupling effects demand a UV completion at the scale of a few TeV, possibly within the reach of the LHC.« less

A 1D-2D coupled SPH-SWE model applied to open channel flow simulations in complicated geometries

NASA Astrophysics Data System (ADS)

Chang, Kao-Hua; Sheu, Tony Wen-Hann; Chang, Tsang-Jung

2018-05-01

In this study, a one- and two-dimensional (1D-2D) coupled model is developed to solve the shallow water equations (SWEs). The solutions are obtained using a Lagrangian meshless method called smoothed particle hydrodynamics (SPH) to simulate shallow water flows in converging, diverging and curved channels. A buffer zone is introduced to exchange information between the 1D and 2D SPH-SWE models. Interpolated water discharge values and water surface levels at the internal boundaries are prescribed as the inflow/outflow boundary conditions in the two SPH-SWE models. In addition, instead of using the SPH summation operator, we directly solve the continuity equation by introducing a diffusive term to suppress oscillations in the predicted water depth. The performance of the two approaches in calculating the water depth is comprehensively compared through a case study of a straight channel. Additionally, three benchmark cases involving converging, diverging and curved channels are adopted to demonstrate the ability of the proposed 1D and 2D coupled SPH-SWE model through comparisons with measured data and predicted mesh-based numerical results. The proposed model provides satisfactory accuracy and guaranteed convergence.

Marriage and Fatherhood Programs

ERIC Educational Resources Information Center

Cowan, Phillip A.; Cowan, Carolyn Pape; Knox, Virginia

2010-01-01

To improve the quality and stability of couple and father-child relationships in fragile families, researchers are beginning to consider how to tailor existing couple-relationship and father-involvement interventions, which are now targeted on married couples, to the specific needs of unwed couples in fragile families. The goal, explain Philip…

Cooperation and competition between two symmetry breakings in a coupled ratchet

NASA Astrophysics Data System (ADS)

Li, Chen-Pu; Chen, Hong-Bin; Fan, Hong; Xie, Ge-Ying; Zheng, Zhi-Gang

2018-03-01

We investigate the collective mechanism of coupled Brownian motors in a flashing ratchet in the presence of coupling symmetry breaking and space symmetry breaking. The dependences of directed current on various parameters are extensively studied in terms of numerical simulations and theoretical analysis. Reversed motion can be achieved by modulating multiple parameters including the spatial asymmetry coefficient, the coupling asymmetry coefficient, the coupling free length and the coupling strength. The dynamical mechanism of these transport properties can be reasonably explained by the effective potential theory and the cooperation or competition between two symmetry breakings. Moreover, adjusting the Gaussian white noise intensity, which can induce weak reversed motion under certain condition, can optimize and manipulate the directed transport of the ratchet system.

On the intramolecular origin of the blue shift of A-H stretching frequencies: triatomic hydrides HAX.

PubMed

Karpfen, Alfred; Kryachko, Eugene S

2009-04-30

A series of intermolecular complexes formed between the triatomic hydrides HAX and various interaction partners are investigated computationally aiming (1) to demonstrate that either an appearance or nonappearance of a blue shift of the A-H stretching frequency is directly related to the sign of the intramolecular coupling that exists between the two degrees of freedom, the A-H and A-X bond lengths, and (2) to offer the following conjecture: the theoretical protonation of a triatomic neutral molecule HAX at the site X is a simple and rather efficient probe of a red or blue shift that the stretching frequency nu(A-H) undergoes upon complex formation regardless of whether this bond is directly involved in hydrogen bonding or not. In other words, to predict whether this A-H bond is capable to display a blue or red shift of nu(A-H), it suffices to compare the equilibrium structures and vibrational spectra of a given molecule with its protonated counterpart. The two above goals are achieved invoking a series of 11 triatomic molecules: HNO, HSN, HPO, and HPS characterized by a negative intramolecular coupling; HON and HNS as intermediate cases; and HOF, HOCl, HCN, HNC, and HCP with a positive intramolecular coupling. For these purposes, the latter molecules are investigated at the MP2/6-311++G(2p,2d) level in the neutral and protonated HAXH(+) forms as well as their complexes with H(2)O and with the fluoromethanes H(3)CF, H(2)CF(2), and HCF(3).

Brain-to-brain coupling during handholding is associated with pain reduction.

PubMed

Goldstein, Pavel; Weissman-Fogel, Irit; Dumas, Guillaume; Shamay-Tsoory, Simone G

2018-03-13

The mechanisms underlying analgesia related to social touch are not clear. While recent research highlights the role of the empathy of the observer to pain relief in the target, the contribution of social interaction to analgesia is unknown. The current study examines brain-to-brain coupling during pain with interpersonal touch and tests the involvement of interbrain synchrony in pain alleviation. Romantic partners were assigned the roles of target (pain receiver) and observer (pain observer) under pain-no-pain and touch-no-touch conditions concurrent with EEG recording. Brain-to-brain coupling in alpha-mu band (8-12 Hz) was estimated by a three-step multilevel analysis procedure based on running window circular correlation coefficient and post hoc power of the findings was calculated using simulations. Our findings indicate that hand-holding during pain administration increases brain-to-brain coupling in a network that mainly involves the central regions of the pain target and the right hemisphere of the pain observer. Moreover, brain-to-brain coupling in this network was found to correlate with analgesia magnitude and observer's empathic accuracy. These findings indicate that brain-to-brain coupling may be involved in touch-related analgesia.

Mutual influences between partners' hormones shape conflict dialog and relationship duration at the initiation of romantic love.

PubMed

Schneiderman, Inna; Kanat-Maymon, Yaniv; Zagoory-Sharon, Orna; Feldman, Ruth

2014-01-01

Early-stage romantic love involves reorganization of neurohormonal systems and behavioral patterns marked by mutual influences between the partners' physiology and behavior. Guided by the biobehavioral synchrony conceptual frame, we tested bidirectional influences between the partners' hormones and conflict behavior at the initiation of romantic love. Participants included 120 new lovers (60 couples) and 40 singles. Plasma levels of five affiliation and stress-related hormones were assessed: oxytocin (OT), prolactin (PRL), testosterone (T), cortisol (CT), and dehydroepiandrosterone sulfate (DHEAS). Couples were observed in conflict interaction coded for empathy and hostility. CT and DHEAS showed direct actor effects: higher CT and DHEAS predicted greater hostility. OT showed direct partner effects: individuals whose partners had higher OT showed greater empathy. T and CT showed combined actor-partner effects. High T predicted greater hostility only when partner also had high T, but lower hostility when partner had low T. Similarly, CT predicted low empathy only in the context of high partner's CT. Mediational analysis indicated that combined high CT in both partners was associated with relationship breakup as mediated by decrease in empathy. Findings demonstrate the mutual influences between hormones and behavior within an attachment bond and underscore the dynamic, co-regulated, and systemic nature of pair-bond formation in humans.

Electron-nuclear coherent spin oscillations probed by spin-dependent recombination

NASA Astrophysics Data System (ADS)

Azaizia, S.; Carrère, H.; Sandoval-Santana, J. C.; Ibarra-Sierra, V. G.; Kalevich, V. K.; Ivchenko, E. L.; Bakaleinikov, L. A.; Marie, X.; Amand, T.; Kunold, A.; Balocchi, A.

2018-04-01

We demonstrate the triggering and detection of coherent electron-nuclear spin oscillations related to the hyperfine interaction in Ga deep paramagnetic centers in GaAsN by band-to-band photoluminescence without an external magnetic field. In contrast to other point defects such as Cr4 + in SiC, Ce3 + in yttrium aluminum garnet crystals, nitrogen-vacancy centers in diamond, and P atoms in silicon, the bound-electron spin in Ga centers is not directly coupled to the electromagnetic field via the spin-orbit interaction. However, this apparent drawback can be turned into an advantage by exploiting the spin-selective capture of conduction band electrons to the Ga centers. On the basis of a pump-probe photoluminescence experiment we measure directly in the temporal domain the hyperfine constant of an electron coupled to a gallium defect in GaAsN by tracing the dynamical behavior of the conduction electron spin-dependent recombination to the defect site. The hyperfine constants and the relative abundance of the nuclei isotopes involved can be determined without the need of an electron spin resonance technique and in the absence of any magnetic field. Information on the nuclear and electron spin relaxation damping parameters can also be estimated from the oscillation amplitude decay and the long-time-delay behavior.

Dilation of epicardial coronary arteries by the G protein-coupled estrogen receptor agonists G-1 and ICI 182,780.

PubMed

Meyer, Matthias R; Baretella, Oliver; Prossnitz, Eric R; Barton, Matthias

2010-01-01

Endogenous estrogens protect from coronary artery disease in premenopausal women, but the mechanisms involved are only partly understood. This study investigated whether activation of the novel G protein-coupled estrogen receptor (GPER, formerly known as GPR30) affects coronary artery tone, and whether this is affected by concomitant blockade of estrogen receptors (ER) alpha and beta. Rings of epicardial porcine coronary arteries suspended in organ chambers were precontracted with prostaglandin F(2)alpha, and direct effects of G-1 (GPER agonist) and ICI 182,780 (GPER agonist and ERalpha/ERbeta antagonist) were determined. In addition, indirect effects on contractility to endothelin-1 and serotonin (a vasoconstrictor released from aggregating platelets during acute myocardial infarction) were assessed. ICI 182,780 and G-1 caused acute dilation of coronary arteries to a comparable degree (p < 0.05 vs. solvent control). Both GPER agonists attenuated contractions to endothelin-1 (p < 0.05 vs. ethanol), but not to serotonin (n.s.). In summary, these findings provide evidence for direct and indirect coronary artery dilator effects of GPER independent of ERalpha and ERbeta, and are the first demonstration of arterial vasodilation in response to ICI 182,780. Copyright 2010 S. Karger AG, Basel.

A measurement concept for hot-spot BRDFs from space

NASA Technical Reports Server (NTRS)

Gerstl, S.A.W.

1996-01-01

Several concepts for canopy hot-spot measurements from space have been investigated. The most promising involves active illumination and bistatic detection that would allow hot-spot angular distribution (BRDF) measurements from space in a search-light mode. The concept includes a pointable illumination source, such as a laser operating at an atmospheric window wavelength, coupled with a number of high spatial-resolution detectors that are clustered around the illumination source in space, receiving photons nearly coaxial with the reto-reflection direction. Microwave control and command among the satellite cluster would allow orienting the direction of the laser beam as well as the focusing detectors simultaneously so that the coupled system can function like a search light with almost unlimited pointing capabilities. The concept is called the Hot-Spot Search-Light (HSSL) satellite. A nominal satellite altitude of 600 km will allow hot-spot BRDF measurements out to about 18 degrees phase angle. The distributed are taking radiometric measurements of the intensity wings of the hot-spot angular distribution without the need for complex imaging detectors. The system can be operated at night for increased signal-to-noise ratio. This way the hot-spot angular signatures can be quantified and parameterized in sufficient detail to extract the biophysical information content of plant architectures.

Directed and persistent movement arises from mechanochemistry of the ParA/ParB system

NASA Astrophysics Data System (ADS)

Hu, Longhua; Vecchiarelli, Anthony G.; Mizuuchi, Kiyoshi; Neuman, Keir C.; Liu, Jian

The segregation of DNA prior to cell division is essential for faithful genetic inheritance. In many bacteria, segregation of the low-copy-number plasmids involves an active partition system composed of ParA ATPase and its stimulator protein ParB. Recent experiments suggest that ParA/ParB system motility is driven by a diffusion-ratchet mechanism in which ParB-coated plasmid both creates and follows a ParA gradient on the nucleoid surface. However, the detailed mechanism of ParA/ParB-mediated directed and persistent movement remains unknown. We develop a theoretical model describing ParA/ParB-mediated motility. We show that the ParA/ParB system can work as a Brownian ratchet, which effectively couples the ATPase-dependent cycling of ParA-nucleoid affinity to the motion of the ParB bound cargo. Paradoxically, the resulting processive motion relies on quenching diffusive plasmid motion through a large number of transient ParA/ParB-mediated tethers to the nucleoid surface. Our work sheds light on a new emergent phenomenon in which non-motor proteins work collectively via mechanochemical coupling to propel cargos -- an ingenious solution shaped by evolution to cope with the lack of processive motor proteins in bacteria.

Analysis of a gauged model with a spin-1/2 field directly coupled to a Rarita-Schwinger spin-3/2 field

NASA Astrophysics Data System (ADS)

Adler, Stephen L.

2018-02-01

We give a detailed analysis of an Abelianized gauge field model in which a Rarita-Schwinger spin-3/2 field is directly coupled to a spin-1/2 field. The model permits a perturbative expansion in powers of the gauge field coupling, and from the Feynman rules for the model we calculate the chiral anomaly.

Perceived Gaze Direction Modulates Neural Processing of Prosocial Decision Making

PubMed Central

Sun, Delin; Shao, Robin; Wang, Zhaoxin; Lee, Tatia M. C.

2018-01-01

Gaze direction is a common social cue implying potential interpersonal interaction. However, little is known about the neural processing of social decision making influenced by perceived gaze direction. Here, we employed functional magnetic resonance imaging (fMRI) method to investigate 27 females when they were engaging in an economic exchange game task during which photos of direct or averted eye gaze were shown. We found that, when averted but not direct gaze was presented, prosocial vs. selfish choices were associated with stronger activations in the right superior temporal gyrus (STG) as well as larger functional couplings between right STG and the posterior cingulate cortex (PCC). Moreover, stronger activations in right STG was associated with quicker actions for making prosocial choice accompanied with averted gaze. The findings suggest that, when the cue implying social contact is absent, the processing of understanding others’ intention and the relationship between self and others is more involved for making prosocial than selfish decisions. These findings could advance our understanding of the roles of subtle cues in influencing prosocial decision making, as well as shedding lights on deficient social cue processing and functioning among individuals with autism spectrum disorder (ASD). PMID:29487516

Exciton Recombination, Energy-, and Charge Transfer in Single- and Multilayer Quantum-Dot Films on Silver Plasmonic Resonators.

PubMed

Shin, Taeho; Cho, Kyung-Sang; Yun, Dong-Jin; Kim, Jinwoo; Li, Xiang-Shu; Moon, Eui-Seong; Baik, Chan-Wook; Il Kim, Sun; Kim, Miyoung; Choi, Jun Hee; Park, Gyeong-Su; Shin, Jai-Kwang; Hwang, Sungwoo; Jung, Tae-Sung

2016-05-17

We examine exciton recombination, energy-, and charge transfer in multilayer CdS/ZnS quantum dots (QDs) on silver plasmonic resonators using photoluminescence (PL) and excitation spectroscopy along with kinetic modeling and simulations. The exciton dynamics including all the processes are strongly affected by the separation distance between QDs and silver resonators, excitation wavelength, and QD film thickness. For a direct contact or very small distance, interfacial charge transfer and tunneling dominate over intrinsic radiative recombination and exciton energy transfer to surface plasmons (SPs), resulting in PL suppression. With increasing distance, however, tunneling diminishes dramatically, while long-range exciton-SP coupling takes place much faster (>6.5 ns) than intrinsic recombination (~200 ns) causing considerable PL enhancement. The exciton-SP coupling strength shows a strong dependence on excitation wavelengths, suggesting the state-specific dynamics of excitons and the down-conversion of surface plasmons involved. The overlayers as well as the bottom monolayer of QD multilayers exhibit significant PL enhancement mainly through long-range exciton-SP coupling. The overall emission behaviors from single- and multilayer QD films on silver resonators are described quantitatively by a photophysical kinetic model and simulations. The present experimental and simulation results provide important and useful design rules for QD-based light harvesting applications using the exciton-surface plasmon coupling.

Exciton Recombination, Energy-, and Charge Transfer in Single- and Multilayer Quantum-Dot Films on Silver Plasmonic Resonators

PubMed Central

Shin, Taeho; Cho, Kyung-Sang; Yun, Dong-Jin; Kim, Jinwoo; Li, Xiang-Shu; Moon, Eui-Seong; Baik, Chan-Wook; Il Kim, Sun; Kim, Miyoung; Choi, Jun Hee; Park, Gyeong-Su; Shin, Jai-Kwang; Hwang, Sungwoo; Jung, Tae-Sung

2016-01-01

We examine exciton recombination, energy-, and charge transfer in multilayer CdS/ZnS quantum dots (QDs) on silver plasmonic resonators using photoluminescence (PL) and excitation spectroscopy along with kinetic modeling and simulations. The exciton dynamics including all the processes are strongly affected by the separation distance between QDs and silver resonators, excitation wavelength, and QD film thickness. For a direct contact or very small distance, interfacial charge transfer and tunneling dominate over intrinsic radiative recombination and exciton energy transfer to surface plasmons (SPs), resulting in PL suppression. With increasing distance, however, tunneling diminishes dramatically, while long-range exciton-SP coupling takes place much faster (>6.5 ns) than intrinsic recombination (~200 ns) causing considerable PL enhancement. The exciton-SP coupling strength shows a strong dependence on excitation wavelengths, suggesting the state-specific dynamics of excitons and the down-conversion of surface plasmons involved. The overlayers as well as the bottom monolayer of QD multilayers exhibit significant PL enhancement mainly through long-range exciton-SP coupling. The overall emission behaviors from single- and multilayer QD films on silver resonators are described quantitatively by a photophysical kinetic model and simulations. The present experimental and simulation results provide important and useful design rules for QD-based light harvesting applications using the exciton-surface plasmon coupling. PMID:27184469

Post-transcriptional labeling by using Suzuki-Miyaura cross-coupling generates functional RNA probes.

PubMed

Walunj, Manisha B; Tanpure, Arun A; Srivatsan, Seergazhi G

2018-06-20

Pd-catalyzed C-C bond formation, an important vertebra in the spine of synthetic chemistry, is emerging as a valuable chemoselective transformation for post-synthetic functionalization of biomacromolecules. While methods are available for labeling protein and DNA, development of an analogous procedure to label RNA by cross-coupling reactions remains a major challenge. Herein, we describe a new Pd-mediated RNA oligonucleotide (ON) labeling method that involves post-transcriptional functionalization of iodouridine-labeled RNA transcripts by using Suzuki-Miyaura cross-coupling reaction. 5-Iodouridine triphosphate (IUTP) is efficiently incorporated into RNA ONs at one or more sites by T7 RNA polymerase. Further, using a catalytic system made of Pd(OAc)2 and 2-aminopyrimidine-4,6-diol (ADHP) or dimethylamino-substituted ADHP (DMADHP), we established a modular method to functionalize iodouridine-labeled RNA ONs in the presence of various boronic acid and ester substrates under very mild conditions (37°C and pH 8.5). This method is highly chemoselective, and offers direct access to RNA ONs labeled with commonly used fluorescent and affinity tags and new fluorogenic environment-sensitive nucleoside probes in a ligand-controlled stereoselective fashion. Taken together, this simple approach of generating functional RNA ON probes by Suzuki-Miyaura coupling will be a very important addition to the resources and tools available for analyzing RNA motifs.

InGaN directional coupler made with a one-step etching technique

NASA Astrophysics Data System (ADS)

Gao, Xumin; Yuan, Jialei; Yang, Yongchao; Zhang, Shuai; Shi, Zheng; Li, Xin; Wang, Yongjin

2017-06-01

We propose, fabricate and characterize an on-chip integration of light source, InGaN waveguide, directional coupler and photodiode, in which AlGaN layers are used as top and bottom optical claddings to form an InGaN waveguide for guiding the in-plane emitted light from the InGaN/GaN multiple-quantum-well light-emitting diode (MQW-LED). The difference in etch rate caused by different exposure windows leads to an etching depth discrepancy using the one-step etching technique, which forms the InGaN directional coupler with the overlapped underlying slab. Light propagation results directly confirm effective light coupling in the InGaN directional coupler, which is achieved through high-order guided modes. The InGaN waveguide couples the modulated light from the InGaN/GaN MQW-LED and transfers part of light to the coupled waveguide via the InGaN directional coupler. The in-plane InGaN/GaN MQW-photodiode absorbs the guided light by the coupled InGaN waveguide and induces the photocurrent. The on-chip InGaN photonic integration experimentally demonstrates an in-plane light communication with a data transmission of 50 Mbps.

Identification of a receptor-independent activator of G protein signaling (AGS8) in ischemic heart and its interaction with Gβγ

PubMed Central

Sato, Motohiko; Cismowski, Mary J.; Toyota, Eiji; Smrcka, Alan V.; Lucchesi, Pamela A.; Chilian, William M.; Lanier, Stephen M.

2006-01-01

As part of a broader effort to identify postreceptor signal regulators involved in specific diseases or organ adaptation, we used an expression cloning system in Saccharomyces cerevisiae to screen cDNA libraries from rat ischemic myocardium, human heart, and a prostate leiomyosarcoma for entities that activated G protein signaling in the absence of a G protein coupled receptor. We report the characterization of activator of G protein signaling (AGS) 8 (KIAA1866), isolated from a rat heart model of repetitive transient ischemia. AGS8 mRNA was induced in response to ventricular ischemia but not by tachycardia, hypertrophy, or failure. Hypoxia induced AGS8 mRNA in isolated adult ventricular cardiomyocytes but not in rat aortic smooth muscle cells, endothelial cells, or cardiac fibroblasts, suggesting a myocyte-specific adaptation mechanism involving remodeling of G protein signaling pathways. The bioactivity of AGS8 in the yeast-based assay was independent of guanine nucleotide exchange by Gα, suggesting an impact on subunit interactions. Subsequent studies indicated that AGS8 interacts directly with Gβγ and this occurs in a manner that apparently does not alter the regulation of the effector PLC-β2 by Gβγ. Mechanistically, AGS8 appears to promote G protein signaling by a previously unrecognized mechanism that involves direct interaction with Gβγ. PMID:16407149

Exciton coupling in molecular crystals

NASA Technical Reports Server (NTRS)

Ake, R. L.

1976-01-01

The implications of perfect exciton coupling and molecular vibrations were investigated, as well as the effect they have on the lifetime of singlet and triplet excitons coupled in a limiting geometry. Crystalline bibenzyl, Cl4Hl4, provided a situation in which these mechanisms involving exciton coupling can be studied in the limit of perfect coupling between units due to the crystal's geometry. This geometry leads to a coupling between the two halves of the molecule resulting in a splitting of the molecular excited states. The study reported involves an experimental spectroscopic approach and begins with the purification of the bibenzyl. The principal experimental apparatus was an emission spectrometer. A closed cycle cryogenic system was used to vary the temperature of the sample between 20 K and 300 K. The desired results are the temperature-dependent emission spectra of the bibenzyl; in addition, the lifetimes and quantum yields measured at each temperature reveal the effect of competing radiationless processes.

Structure of the transcriptional regulator LmrR and its mechanism of multidrug recognition.

PubMed

Madoori, Pramod Kumar; Agustiandari, Herfita; Driessen, Arnold J M; Thunnissen, Andy-Mark W H

2009-01-21

LmrR is a PadR-related transcriptional repressor that regulates the production of LmrCD, a major multidrug ABC transporter in Lactococcus lactis. Transcriptional regulation is presumed to follow a drug-sensitive induction mechanism involving the direct binding of transporter ligands to LmrR. Here, we present crystal structures of LmrR in an apo state and in two drug-bound states complexed with Hoechst 33342 and daunomycin. LmrR shows a common topology containing a typical beta-winged helix-turn-helix domain with an additional C-terminal helix involved in dimerization. Its dimeric organization is highly unusual with a flat-shaped hydrophobic pore at the dimer centre serving as a multidrug-binding site. The drugs bind in a similar manner with their aromatic rings sandwiched in between the indole groups of two dimer-related tryptophan residues. Multidrug recognition is facilitated by conformational plasticity and the absence of drug-specific hydrogen bonds. Combined analyses using site-directed mutagenesis, fluorescence-based drug binding and protein-DNA gel shift assays reveal an allosteric coupling between the multidrug- and DNA-binding sites of LmrR that most likely has a function in the induction mechanism.

On-chip spin-controlled orbital angular momentum directional coupling

NASA Astrophysics Data System (ADS)

Xie, Zhenwei; Lei, Ting; Si, Guangyuan; Du, Luping; Lin, Jiao; Min, Changjun; Yuan, Xiaocong

2018-01-01

Optical vortex beams have many potential applications in the particle trapping, quantum encoding, optical orbital angular momentum (OAM) communications and interconnects. However, the on-chip compact OAM detection is still a big challenge. Based on a holographic configuration and a spin-dependent structure design, we propose and demonstrate an on-chip spin-controlled OAM-mode directional coupler, which can couple the OAM signal to different directions due to its topological charge. While the directional coupling function can be switched on/off by altering the spin of incident beam. Both simulation and experimental measurements verify the validity of the proposed approach. This work would benefit the on-chip OAM devices for optical communications and high dimensional quantum coding/decoding in the future.

Cell adhesion controlled by adhesion G protein-coupled receptor GPR124/ADGRA2 is mediated by a protein complex comprising intersectins and Elmo-Dock.

PubMed

Hernández-Vásquez, Magda Nohemí; Adame-García, Sendi Rafael; Hamoud, Noumeira; Chidiac, Rony; Reyes-Cruz, Guadalupe; Gratton, Jean Philippe; Côté, Jean-François; Vázquez-Prado, José

2017-07-21

Developmental angiogenesis and the maintenance of the blood-brain barrier involve endothelial cell adhesion, which is linked to cytoskeletal dynamics. GPR124 (also known as TEM5/ADGRA2) is an adhesion G protein-coupled receptor family member that plays a pivotal role in brain angiogenesis and in ensuring a tight blood-brain barrier. However, the signaling properties of GPR124 remain poorly defined. Here, we show that ectopic expression of GPR124 promotes cell adhesion, additive to extracellular matrix-dependent effect, coupled with filopodia and lamellipodia formation and an enrichment of a pool of the G protein-coupled receptor at actin-rich cellular protrusions containing VASP, a filopodial marker. Accordingly, GPR124-expressing cells also displayed increased activation of both Rac and Cdc42 GTPases. Mechanistically, we uncover novel direct interactions between endogenous GPR124 and the Rho guanine nucleotide exchange factors Elmo/Dock and intersectin (ITSN). Small fragments of either Elmo or ITSN1 that bind GPR124 blocked GPR124-induced cell adhesion. In addition, Gβγ interacts with the C-terminal tail of GPR124 and promotes the formation of a GPR124-Elmo complex. Furthermore, GPR124 also promotes the activation of the Elmo-Dock complex, as measured by Elmo phosphorylation on a conserved C-terminal tyrosine residue. Interestingly, Elmo and ITSN1 also interact with each other independently of their GPR124-recognition regions. Moreover, endogenous phospho-Elmo and ITSN1 co-localize with GPR124 at lamellipodia of adhering endothelial cells, where GPR124 expression contributes to polarity acquisition during wound healing. Collectively, our results indicate that GPR124 promotes cell adhesion via Elmo-Dock and ITSN. This constitutes a previously unrecognized complex formed of atypical and conventional Rho guanine nucleotide exchange factors for Rac and Cdc42 that is putatively involved in GPR124-dependent angiogenic responses. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

Single-Molecule Imaging of RNA Splicing in Live Cells.

PubMed

Rino, José; Martin, Robert M; Carvalho, Célia; de Jesus, Ana C; Carmo-Fonseca, Maria

2015-01-01

Expression of genetic information in eukaryotes involves a series of interconnected processes that ultimately determine the quality and amount of proteins in the cell. Many individual steps in gene expression are kinetically coupled, but tools are lacking to determine how temporal relationships between chemical reactions contribute to the output of the final gene product. Here, we describe a strategy that permits direct measurements of intron dynamics in single pre-mRNA molecules in live cells. This approach reveals that splicing can occur much faster than previously proposed and opens new avenues for studying how kinetic mechanisms impact on RNA biogenesis. © 2015 Elsevier Inc. All rights reserved.

Entanglement distribution in star network based on spin chain in diamond

NASA Astrophysics Data System (ADS)

Zhu, Yuan-Ming; Ma, Lei

2018-06-01

After star network of spins was proposed, generating entanglement directly through spin interactions between distant parties became possible. We propose an architecture which involves coupled spin chains based on nitrogen-vacancy centers and nitrogen defect spins to expand star network. The numerical analysis shows that the maximally achievable entanglement Em exponentially decays with the length of spin chains M and spin noise. The entanglement capability of this configuration under the effect of disorder and spin loss is also studied. Moreover, it is shown that with this kind of architecture, star network of spins is feasible in measurement of magnetic-field gradient.

A complex systems approach to constructing better models for managing financial markets and the economy

NASA Astrophysics Data System (ADS)

Farmer, J. Doyne; Gallegati, M.; Hommes, C.; Kirman, A.; Ormerod, P.; Cincotti, S.; Sanchez, A.; Helbing, D.

2012-11-01

We outline a vision for an ambitious program to understand the economy and financial markets as a complex evolving system of coupled networks of interacting agents. This is a completely different vision from that currently used in most economic models. This view implies new challenges and opportunities for policy and managing economic crises. The dynamics of such models inherently involve sudden and sometimes dramatic changes of state. Further, the tools and approaches we use emphasize the analysis of crises rather than of calm periods. In this they respond directly to the calls of Governors Bernanke and Trichet for new approaches to macroeconomic modelling.

Direct-to-digital holography and holovision

DOEpatents

Thomas, Clarence E.; Baylor, Larry R.; Hanson, Gregory R.; Rasmussen, David A.; Voelkl, Edgar; Castracane, James; Simkulet, Michelle; Clow, Lawrence

2000-01-01

Systems and methods for direct-to-digital holography are described. An apparatus includes a laser; a beamsplitter optically coupled to the laser; a reference beam mirror optically coupled to the beamsplitter; an object optically coupled to the beamsplitter, a focusing lens optically coupled to both the reference beam mirror and the object; and a digital recorder optically coupled to the focusing lens. A reference beam is incident upon the reference beam mirror at a non-normal angle, and the reference beam and an object beam are focused by the focusing lens at a focal plane of the digital recorder to form an image. The systems and methods provide advantages in that computer assisted holographic measurements can be made.

Correlation-based regularization and gradient operators for (joint) inversion on unstructured meshes

NASA Astrophysics Data System (ADS)

Jordi, Claudio; Doetsch, Joseph; Günther, Thomas; Schmelzbach, Cedric; Robertsson, Johan

2017-04-01

When working with unstructured meshes for geophysical inversions, special attention should be paid to the design of the operators that are used for regularizing the inverse problem and coupling of different property models in joint inversions. Regularization constraints for inversions on unstructured meshes are often defined in a rather ad-hoc manner and usually only involve the cell to which the operator is applied and its direct neighbours. Similarly, most structural coupling operators for joint inversion, such as the popular cross-gradients operator, are only defined in the direct neighbourhood of a cell. As a result, the regularization and coupling length scales and strength of these operators depend on the discretization as well as cell sizes and shape. Especially for unstructured meshes, where the cell sizes vary throughout the model domain, the dependency of the operator on the discretization may lead to artefacts. Designing operators that are based on a spatial correlation model allows to define correlation length scales over which an operator acts (called footprint), reducing the dependency on the discretization and the effects of variable cell sizes. Moreover, correlation-based operators can accommodate for expected anisotropy by using different length scales in horizontal and vertical directions. Correlation-based regularization operators also known as stochastic regularization operators have already been successfully applied to inversions on regular grids. Here, we formulate stochastic operators for unstructured meshes and apply them in 2D surface and 3D cross-well electrical resistivity tomography data inversion examples of layered media. Especially for the synthetic cross-well example, improved inversion results are achieved when stochastic regularization is used instead of a classical smoothness constraint. For the case of cross-gradients operators for joint inversion, the correlation model is used to define the footprint of the operator and weigh the contributions of the property values that are used to calculate the cross-gradients. In a first series of synthetic-data tests, we examined the mesh dependency of the cross-gradients operators. Compared to operators that are only defined in the direct neighbourhood of a cell, the dependency on the cell size of the cross-gradients calculation is markedly reduced when using operators with larger footprints. A second test with synthetic models focussed on the effect of small-scale variabilities of the parameter value on the cross-gradients calculation. Small-scale variabilities that are superimposed on a global trend of the property value can potentially degrade the cross-gradients calculation and destabilize joint inversion. We observe that the cross-gradients from operators with footprints larger than the length scale of the variabilities are less affected compared to operators with a small footprint. In joint inversions on unstructured meshes, we thus expect the correlation-based coupling operators to ensure robust coupling on a physically meaningful scale.

MARRIAGE PROBLEMS—Dealing with Them in Private Practice

PubMed Central

Ruskin, Isidore W.

1959-01-01

Marriages and divorces in Los Angeles County almost equal each other. Marriage per se is not the cause of neurosis. When two neurotic persons marry, the resulting neurotic interaction too often ends in conflict, broken homes and a new generation of neurotic children. Psychotherapy must be related to the diagnosis of family psychopathology, should include all the involved members and should be directed toward the realistic goal of integrating them into family living. Of 100 cases taken from the author's experience, 64 involved married couples and the majority of these had serious interspouse conflicts. In 37 cases both spouses were treated and substantial psychotherapy was given to one or both of the partners. It included one or more modalities varying from electroshock therapy, tranquilizers, and such psychotherapy as supportive, dynamic interpretive, individual, spouses together, group and hypnotherapy. Thirteen achieved clinical recovery, nine improved, twelve were still in therapy. In three cases therapy failed. PMID:13629353

A graphic approach to include dissipative-like effects in reversible thermal cycles

NASA Astrophysics Data System (ADS)

Gonzalez-Ayala, Julian; Arias-Hernandez, Luis Antonio; Angulo-Brown, Fernando

2017-05-01

Since the decade of 1980's, a connection between a family of maximum-work reversible thermal cycles and maximum-power finite-time endoreversible cycles has been established. The endoreversible cycles produce entropy at their couplings with the external heat baths. Thus, this kind of cycles can be optimized under criteria of merit that involve entropy production terms. Meanwhile the relation between the concept of work and power is quite direct, apparently, the finite-time objective functions involving entropy production have not reversible counterparts. In the present paper we show that it is also possible to establish a connection between irreversible cycle models and reversible ones by means of the concept of "geometric dissipation", which has to do with the equivalent role of a deficit of areas between some reversible cycles and the Carnot cycle and actual dissipative terms in a Curzon-Ahlborn engine.

A-type potassium channels differentially tune afferent pathways from rat solitary tract nucleus to caudal ventrolateral medulla or paraventricular hypothalamus

PubMed Central

Bailey, T W; Hermes, S M; Whittier, K L; Aicher, S A; Andresen, M C

2007-01-01

The solitary tract nucleus (NTS) conveys visceral information to diverse central networks involved in homeostatic regulation. Although afferent information content arriving at various CNS sites varies substantially, little is known about the contribution of processing within the NTS to these differences. Using retrograde dyes to identify specific NTS projection neurons, we recently reported that solitary tract (ST) afferents directly contact NTS neurons projecting to caudal ventrolateral medulla (CVLM) but largely only indirectly contact neurons projecting to the hypothalamic paraventricular nucleus (PVN). Since intrinsic properties impact information transmission, here we evaluated potassium channel expression and somatodendritic morphology of projection neurons and their relation to afferent information output directed to PVN or CVLM pathways. In slices, tracer-identified projection neurons were classified as directly or indirectly (polysynaptically) coupled to ST afferents by EPSC latency characteristics (directly coupled, jitter < 200 μs). In each neuron, voltage-dependent potassium currents (IK) were evaluated and, in representative neurons, biocytin-filled structures were quantified. Both CVLM- and PVN-projecting neurons had similar, tetraethylammonium-sensitive IK. However, only PVN-projecting NTS neurons displayed large transient, 4aminopyridine-sensitive, A-type currents (IKA). PVN-projecting neurons had larger cell bodies with more elaborate dendritic morphology than CVLM-projecting neurons. ST shocks faithfully (> 75%) triggered action potentials in CVLM-projecting neurons but spike output was uniformly low (< 20%) in PVN-projecting neurons. Pre-conditioning hyperpolarization removed IKA inactivation and attenuated ST-evoked spike generation along PVN but not CVLM pathways. Thus, multiple differences in structure, organization, synaptic transmission and ion channel expression tune the overall fidelity of afferent signals that reach these destinations. PMID:17510187

DIRECTIONAL COUPLERS

DOEpatents

Nigg, D.J.

1961-12-01

A directional coupler of small size is designed. Stripline conductors of non-rectilinear configuration, and separated from each other by a thin dielectric spacer. cross each other at least at two locations at right angles, thus providing practically pure capacitive coupling which substantially eliminates undesirable inductive coupling. The conductors are sandwiched between a pair of ground planes. The coupling factor is dependent only on the thickness and dielectric constant of the dielectric spacer at the point of conductor crossover. (AEC)

Does alcohol involvement increase the severity of intimate partner violence?

PubMed

McKinney, Christy M; Caetano, Raul; Rodriguez, Lori A; Okoro, Ngozi

2010-04-01

Most studies that have examined alcohol use immediately prior to intimate partner violence (IPV) have been limited to male-to-female partner violence (MFPV) and are subject to a number of methodological limitations. We add new information concerning the relationship between alcohol involvement and severity of IPV, MFPV, and female-to-male partner violence (FMPV). We analyzed data from a 1995 U.S. national population-based survey of couples > or = 18 years old. We examined 436 couples who reported IPV and had information on alcohol involvement with IPV. We measured IPV using a revised Conflict Tactics Scale, Form R that asked respondents about 11 violent behaviors in the past year. Respondents were classified into mutually exclusive categories as having experienced mild only or mild + severe ("severe") IPV, MFPV or FMPV. Respondents were also asked if they or their partner were drinking at the time the violent behavior occurred and were classified as exposed to IPV with or without alcohol involvement. We estimated proportions, odds ratios, 95% confidence intervals, and p-values of the proposed associations, accounting for the complex survey design. Overall, 30.2% of couples who reported IPV reported alcohol involved IPV; 69.8% reported no alcohol involvement. In adjusted analyses, those reporting severe (vs. mild only) IPV were more than twice as likely to report alcohol involvement. In adjusted analyses, those reporting severe (vs. mild) MFPV or FMPV were more likely to report female but not male alcohol involvement. Though estimates were positive and strong, most confidence intervals were compatible with a wide range of estimates including no association. Our findings suggest alcohol involvement of either or both in the couple increases the risk of severe IPV. Our findings also suggest female alcohol use may play an important role in determining the severity of IPV, MFPV or FMPV.

Buckling analysis of orthotropic protein microtubules under axial and radial compression based on couple stress theory.

PubMed

Beni, Yaghoub Tadi; Zeverdejani, M Karimi; Mehralian, Fahimeh

2017-10-01

Protein microtubules (MTs) are one of the important intercellular components and have a vital role in the stability and strength of the cells. Due to applied external loads, protein microtubules may be involved buckling phenomenon. Due to impact of protein microtubules in cell reactions, it is important to determine their critical buckling load. Considering nature of protein microtubules, various parameters are effective on microtubules buckling. The small size of microtubules and also lack of uniformity of MTs properties in different directions caused the necessity of accuracy in the analysis of these bio-structure. In fact, microtubules must be considered as a size dependent cylinder, which behave as an orthotropic material. Hence, in the present work using first-order shear deformation model (FSDT), the buckling equations of anisotropic MTs are derived based on new modified couple stress theory (NMCST). After solving the stability equations, the influences of various parameters are measured on the MTs critical buckling load. Copyright © 2017 Elsevier Inc. All rights reserved.

Traveling waves in a coupled reaction-diffusion and difference model of hematopoiesis

NASA Astrophysics Data System (ADS)

Adimy, M.; Chekroun, A.; Kazmierczak, B.

2017-04-01

The formation and development of blood cells is a very complex process, called hematopoiesis. This process involves a small population of cells called hematopoietic stem cells (HSCs). The HSCs are undifferentiated cells, located in the bone marrow before they become mature blood cells and enter the blood stream. They have a unique ability to produce either similar cells (self-renewal), or cells engaged in one of different lineages of blood cells: red blood cells, white cells and platelets (differentiation). The HSCs can be either in a proliferating or in a quiescent phase. In this paper, we distinguish between dividing cells that enter directly to the quiescent phase and dividing cells that return to the proliferating phase to divide again. We propose a mathematical model describing the dynamics of HSC population, taking into account their spatial distribution. The resulting model is a coupled reaction-diffusion equation and difference equation with delay. We study the existence of monotone traveling wave fronts and the asymptotic speed of spread.

Pilot-in-the-Loop Analysis of Propulsive-Only Flight Control Systems

NASA Technical Reports Server (NTRS)

Chou, Hwei-Lan; Biezad, Daniel J.

1996-01-01

Longitudinal control system architectures are presented which directly couple flight stick motions to throttle commands for a multi-engine aircraft. This coupling enables positive attitude control with complete failure of the flight control system. The architectures chosen vary from simple feedback gains to classical lead-lag compensators with and without prefilters. Each architecture is reviewed for its appropriateness for piloted flight. The control systems are then analyzed with pilot-in-the-loop metrics related to bandwidth required for landing. Results indicate that current and proposed bandwidth requirements should be modified for throttles only flight control. Pilot ratings consistently showed better ratings than predicted by analysis. Recommendations are made for more robust design and implementation. The use of Quantitative Feedback Theory for compensator design is discussed. Although simple and effective augmented control can be achieved in a wide variety of failed configurations, a few configuration characteristics are dominant for pilot-in-the-loop control. These characteristics will be tested in a simulator study involving failed flight controls for a multi-engine aircraft.

Photo-induced oxidant-free oxidative C-H/N-H cross-coupling between arenes and azoles

NASA Astrophysics Data System (ADS)

Niu, Linbin; Yi, Hong; Wang, Shengchun; Liu, Tianyi; Liu, Jiamei; Lei, Aiwen

2017-02-01

Direct cross-coupling between simple arenes and heterocyclic amines under mild conditions is undoubtedly important for C-N bonds construction. Selective C(sp2)-H amination is more valuable. Herein we show a selective C(sp2)-H amination of arenes (alkyl-substituted benzenes, biphenyl and anisole derivatives) accompanied by hydrogen evolution by using heterocyclic azoles as nitrogen sources. The reaction is selective for C(sp2)-H bonds, providing a mild route to N-arylazoles. The KIE (kinetic isotope effect) experiment reveals the cleavage of C-H bond is not involved in the rate-determining step. Kinetic studies indicate the first-order behaviour with respect to the arene component. It is interesting that this system works without the need for any sacrificial oxidant and is highly selective for C(sp2)-H activation, whereas C(sp3)-H bonds are unaffected. This study may have significant implications for the functionalization of methylarenes which are sensitive to oxidative conditions.

Fully Synthetic Granulocyte Colony-Stimulating Factor Enabled by Isonitrile-Mediated Coupling of Large, Side-Chain-Unprotected Peptides

PubMed Central

Roberts, Andrew G.; Johnston, Eric V.; Shieh, Jae-Hung; Sondey, Joseph P.; Hendrickson, Ronald C.; Moore, Malcolm A. S.; Danishefsky, Samuel J.

2015-01-01

Human granulocyte colony-stimulating factor (G-CSF) is an endogenous glycoprotein involved in hematopoiesis. Natively glycosylated and nonglycosylated recombinant forms, lenograstim and filgrastim, respectively, are used clinically to manage neutropenia in patients undergoing chemotherapeutic treatment. Despite their comparable therapeutic potential, the purpose of O-linked glycosylation at Thr133 remains a subject of controversy. In light of this, we have developed a synthetic platform to prepare G-CSF aglycone with the goal of enabling access to native and designed glycoforms with site-selectivity and glycan homogeneity. To address the synthesis of a relatively large, aggregation-prone sequence, we advanced an isonitrile-mediated ligation method. The chemoselective activation and coupling of C-terminal peptidyl Gly thioacids with the N-terminus of an unprotected peptide provide ligated peptides directly in a manner complementary to that with conventional native chemical ligation–desulfurization strategies. Herein, we describe the details and application of this method as it enabled the convergent total synthesis of G-CSF aglycone. PMID:26401918

A locally conservative stabilized continuous Galerkin finite element method for two-phase flow in poroelastic subsurfaces

NASA Astrophysics Data System (ADS)

Deng, Q.; Ginting, V.; McCaskill, B.; Torsu, P.

2017-10-01

We study the application of a stabilized continuous Galerkin finite element method (CGFEM) in the simulation of multiphase flow in poroelastic subsurfaces. The system involves a nonlinear coupling between the fluid pressure, subsurface's deformation, and the fluid phase saturation, and as such, we represent this coupling through an iterative procedure. Spatial discretization of the poroelastic system employs the standard linear finite element in combination with a numerical diffusion term to maintain stability of the algebraic system. Furthermore, direct calculation of the normal velocities from pressure and deformation does not entail a locally conservative field. To alleviate this drawback, we propose an element based post-processing technique through which local conservation can be established. The performance of the method is validated through several examples illustrating the convergence of the method, the effectivity of the stabilization term, and the ability to achieve locally conservative normal velocities. Finally, the efficacy of the method is demonstrated through simulations of realistic multiphase flow in poroelastic subsurfaces.

Imaging of persistent cAMP signaling by internalized G protein-coupled receptors.

PubMed

Calebiro, Davide; Nikolaev, Viacheslav O; Lohse, Martin J

2010-07-01

G protein-coupled receptors (GPCRs) are the largest family of plasma membrane receptors. They mediate the effects of several endogenous cues and serve as important pharmacological targets. Although many biochemical events involved in GPCR signaling have been characterized in great detail, little is known about their spatiotemporal dynamics in living cells. The recent advent of optical methods based on fluorescent resonance energy transfer allows, for the first time, to directly monitor GPCR signaling in living cells. Utilizing these methods, it has been recently possible to show that the receptors for two protein/peptide hormones, the TSH and the parathyroid hormone, continue signaling to cAMP after their internalization into endosomes. This type of intracellular signaling is persistent and apparently triggers specific cellular outcomes. Here, we review these recent data and explain the optical methods used for such studies. Based on these findings, we propose a revision of the current model of the GPCR-cAMP signaling pathway to accommodate receptor signaling at endosomes.

"He's more typically female because he's not afraid to cry": connecting heterosexual gender relations and men's depression.

PubMed

Oliffe, John L; Kelly, Mary T; Bottorff, Joan L; Johnson, Joy L; Wong, Sabrina T

2011-09-01

Depression, a disorder often thought of as a women's health issue, is underreported in men, and little is known about how heterosexual couples respond when the male partner is depressed. Within the context of men's depression, couples may be challenged to make life adjustments that impact their gender relations. The findings detailed in this article are drawn from an innovative qualitative study of 26 Canadian heterosexual couples (26 men and their 26 women partners) in which the man had a formal diagnosis and/or self-identified as depressed. Participants completed individual, semi structured interviews that focused on exploring how masculinities and femininities intersect to forge particular heterosexual gender relations in the context of men's depression. A social constructionist gender analysis revealed three couple patterns: trading places, business as usual, and edgy tensions. Trading places refers to couples who embodied some atypical masculine and feminine roles to compensate for the men's depression-induced losses (e.g., men as homemakers and women as breadwinners). Women partners in these dyads broke with feminine ideals in how they provided partner support by employing tough love strategies for self-protection and a means of prompting the men's self-management of their depression. Couples involved in business as usual co-constructed men's alignment with masculine workman ideals and women's support of their partner to counter and conceal men's depression induced-deficits. Also described were edgy tensions, where a mismatch of gender expectations fueled resentment and dysfunction that threatened the viability of some relationships. Overall, the limits of women's resilience and care-giving were evident, yet the findings also reveal how men's management of their depression was directly influenced by their partner. Opportunities for couples to assess their relationship dynamics within a broad range of gender relations might support couples' connectedness and life quality amid the challenges that accompany men's depression. Crown Copyright © 2011. Published by Elsevier Ltd. All rights reserved.

Control of the neurovascular coupling by nitric oxide-dependent regulation of astrocytic Ca2+ signaling

PubMed Central

Muñoz, Manuel F.; Puebla, Mariela; Figueroa, Xavier F.

2015-01-01

Neuronal activity must be tightly coordinated with blood flow to keep proper brain function, which is achieved by a mechanism known as neurovascular coupling. Then, an increase in synaptic activity leads to a dilation of local parenchymal arterioles that matches the enhanced metabolic demand. Neurovascular coupling is orchestrated by astrocytes. These glial cells are located between neurons and the microvasculature, with the astrocytic endfeet ensheathing the vessels, which allows fine intercellular communication. The neurotransmitters released during neuronal activity reach astrocytic receptors and trigger a Ca2+ signaling that propagates to the endfeet, activating the release of vasoactive factors and arteriolar dilation. The astrocyte Ca2+ signaling is coordinated by gap junction channels and hemichannels formed by connexins (Cx43 and Cx30) and channels formed by pannexins (Panx-1). The neuronal activity-initiated Ca2+ waves are propagated among neighboring astrocytes directly via gap junctions or through ATP release via connexin hemichannels or pannexin channels. In addition, Ca2+ entry via connexin hemichannels or pannexin channels may participate in the regulation of the astrocyte signaling-mediated neurovascular coupling. Interestingly, nitric oxide (NO) can activate connexin hemichannel by S-nitrosylation and the Ca2+-dependent NO-synthesizing enzymes endothelial NO synthase (eNOS) and neuronal NOS (nNOS) are expressed in astrocytes. Therefore, the astrocytic Ca2+ signaling triggered in neurovascular coupling may activate NO production, which, in turn, may lead to Ca2+ influx through hemichannel activation. Furthermore, NO release from the hemichannels located at astrocytic endfeet may contribute to the vasodilation of parenchymal arterioles. In this review, we discuss the mechanisms involved in the regulation of the astrocytic Ca2+ signaling that mediates neurovascular coupling, with a special emphasis in the possible participation of NO in this process. PMID:25805969

Control of magnetic direction in multi-layer ferromagnetic devices by bias voltage

DOEpatents

You, Chun-Yeol; Bader, Samuel D.

2001-01-01

A system for controlling the direction of magnetization of materials comprising a ferromagnetic device with first and second ferromagnetic layers. The ferromagnetic layers are disposed such that they combine to form an interlayer with exchange coupling. An insulating layer and a spacer layer are located between the first and second ferromagnetic layers. A direct bias voltage is applied to the interlayer exchange coupling, causing the direction of magnetization of the second ferromagnetic layer to change. This change of magnetization direction occurs in the absence of any applied external magnetic field.

Coupled vibration of isotropic metal hollow cylinders with large geometrical dimensions

NASA Astrophysics Data System (ADS)

Lin, Shuyu

2007-08-01

In this paper, the coupled vibration of isotropic metal hollow cylinders with large geometrical dimensions is studied by using an approximate analytic method. According to this method, when the equivalent mechanical coupling coefficient that is defined as the stress ratio is introduced, the coupled vibration of a metal hollow cylinder is reduced to two equivalent one-dimensional vibrations, one is an equivalent longitudinal extensional vibration in the height direction of the cylinder, and the other is an equivalent plane radial vibration in the radius direction. These two equivalent vibrations are coupled to each other by the equivalent mechanical coupling coefficient. The resonance frequency equation of metal hollow cylinders in coupled vibration is derived and longitudinal and radial resonance frequencies are computed. For comparison, the resonance frequencies of the hollow cylinders are also computed by using numerical method. The analysis shows that the results from these two methods are in a good agreement with each other.

Black holes and stars in Horndeski theory

NASA Astrophysics Data System (ADS)

Babichev, Eugeny; Charmousis, Christos; Lehébel, Antoine

2016-08-01

We review black hole and star solutions for Horndeski theory. For non-shift symmetric theories, black holes involve a Kaluza-Klein reduction of higher dimensional Lovelock solutions. On the other hand, for shift symmetric theories of Horndeski and beyond Horndeski, black holes involve two classes of solutions: those that include, at the level of the action, a linear coupling to the Gauss-Bonnet term and those that involve time dependence in the galileon field. We analyze the latter class in detail for a specific subclass of Horndeski theory, discussing the general solution of a static and spherically symmetric spacetime. We then discuss stability issues, slowly rotating solutions as well as black holes coupled to matter. The latter case involves a conformally coupled scalar field as well as an electromagnetic field and the (primary) hair black holes thus obtained. We review and discuss the recent results on neutron stars in Horndeski theories.

Online coupled regional meteorology-chemistry models in Europe: current status and prospects

NASA Astrophysics Data System (ADS)

Baklanov, A.; Schluenzen, K. H.; Suppan, P.; Baldasano, J.; Brunner, D.; Aksoyoglu, S.; Carmichael, G.; Douros, J.; Flemming, J.; Forkel, R.; Galmarini, S.; Gauss, M.; Grell, G.; Hirtl, M.; Joffre, S.; Jorba, O.; Kaas, E.; Kaasik, M.; Kallos, G.; Kong, X.; Korsholm, U.; Kurganskiy, A.; Kushta, J.; Lohmann, U.; Mahura, A.; Manders-Groot, A.; Maurizi, A.; Moussiopoulos, N.; Rao, S. T.; Savage, N.; Seigneur, C.; Sokhi, R.; Solazzo, E.; Solomos, S.; Sørensen, B.; Tsegas, G.; Vignati, E.; Vogel, B.; Zhang, Y.

2013-05-01

The simulation of the coupled evolution of atmospheric dynamics, pollutant transport, chemical reactions and atmospheric composition is one of the most challenging tasks in environmental modelling, climate change studies, and weather forecasting for the next decades as they all involve strongly integrated processes. Weather strongly influences air quality (AQ) and atmospheric transport of hazardous materials, while atmospheric composition can influence both weather and climate by directly modifying the atmospheric radiation budget or indirectly affecting cloud formation. Until recently, however, due to the scientific complexities and lack of computational power, atmospheric chemistry and weather forecasting have developed as separate disciplines, leading to the development of separate modelling systems that are only loosely coupled. The continuous increase in computer power has now reached a stage that enables us to perform online coupling of regional meteorological models with atmospheric chemical transport models. The focus on integrated systems is timely, since recent research has shown that meteorology and chemistry feedbacks are important in the context of many research areas and applications, including numerical weather prediction (NWP), AQ forecasting as well as climate and Earth system modelling. However, the relative importance of online integration and its priorities, requirements and levels of detail necessary for representing different processes and feedbacks can greatly vary for these related communities: (i) NWP, (ii) AQ forecasting and assessments, (iii) climate and earth system modelling. Additional applications are likely to benefit from online modelling, e.g.: simulation of volcanic ash or forest fire plumes, pollen warnings, dust storms, oil/gas fires, geo-engineering tests involving changes in the radiation balance. The COST Action ES1004 - European framework for online integrated air quality and meteorology modelling (EuMetChem) - aims at paving the way towards a new generation of online integrated atmospheric chemical transport and meteorology modelling with two-way interactions between different atmospheric processes including dynamics, chemistry, clouds, radiation, boundary layer and emissions. As its first task, we summarise the current status of European modelling practices and experience with online coupled modelling of meteorology with atmospheric chemistry including feedback mechanisms and attempt reviewing the various issues connected to the different modules of such online coupled models but also providing recommendations for coping with them for the benefit of the modelling community at large.

Factors associated with father involvement in infant care.

PubMed

Falceto, Olga G; Fernandes, Carmen L; Baratojo, Claudia; Giugliani, Elsa R J

2008-12-01

To identify factors associated with the lack of active father involvement in infant care at four months of age. Cross-sectional study involving families of 153 infants at four months of age, interviewed in their homes by two family therapists. In addition to father involvement in infant care, sociodemographic, parental mental health (using the Self Report Questionnaire-20 scale and Diagnostic and Statistical Manual of Mental Disorders-IV criteria assessment) and quality of couple relationship characteristics (using the Assessment of Relational Functioning from Diagnostic and Statistical Manual of Mental Disorders-IV) were analyzed. Poisson regression was employed to assess the association between lack of father involvement in child care and the variables selected. Prevalence ratio was used to estimate the magnitude of associations. Fathers of 13% of infants had no contact with their children. Among families whose parents lived together (78% of all), 33% of the fathers reported not actively participating in their children's care. Problematic couple relationship and mother as a housewife were associated with lack of father involvement in infant care. High prevalence of families whose father is not actively involved with infant care, especially when couple relationship is problematic and the mother does not have a paid job.

Models for electromagnetic coupling of lightning onto multiconductor cables in underground cavities

NASA Astrophysics Data System (ADS)

Higgins, Matthew Benjamin

This dissertation documents the measurements, analytical modeling, and numerical modeling of electromagnetic transfer functions to quantify the ability of cloud-to-ground lightning strokes (including horizontal arc-channel components) to couple electromagnetic energy onto multiconductor cables in an underground cavity. Measurements were performed at the Sago coal mine located near Buckhannon, WV. These transfer functions, coupled with mathematical representations of lightning strokes, are then used to predict electric fields within the mine and induced voltages on a cable that was left abandoned in the sealed area of the Sago mine. If voltages reached high enough levels, electrical arcing could have occurred from the abandoned cable. Electrical arcing is known to be an effective ignition source for explosive gas mixtures. Two coupling mechanisms were measured: direct and indirect drive. Direct coupling results from the injection or induction of lightning current onto metallic conductors such as the conveyors, rails, trolley communications cable, and AC power shields that connect from the outside of the mine to locations deep within the mine. Indirect coupling results from electromagnetic field propagation through the earth as a result of a cloud-to-ground lightning stroke or a long, low-altitude horizontal current channel from a cloud-to-ground stroke. Unlike direct coupling, indirect coupling does not require metallic conductors in a continuous path from the surface to areas internal to the mine. Results from the indirect coupling measurements and analysis are of great concern. The field measurements, modeling, and analysis indicate that significant energy can be coupled directly into the sealed area of the mine. Due to the relatively low frequency content of lightning (< 100 kHz), electromagnetic energy can readily propagate through hundreds of feet of earth. Indirect transfer function measurements compare extremely well with analytical and computational models developed for the Sago site which take into account measured soil properties.

The Experience of Couples in the Process of Treatment of Pathological Gambling: Couple vs. Individual Therapy.

PubMed

Tremblay, Joël; Dufour, Magali; Bertrand, Karine; Blanchette-Martin, Nadine; Ferland, Francine; Savard, Annie-Claude; Saint-Jacques, Marianne; Côté, Mélissa

2017-01-01

Context: Couple treatment for pathological gambling is an innovative strategy. There are some results supporting its potential effectiveness, but little is known about the subjective experiences of the participants. Objective: The aim of this article is to document the experiences of gamblers and their partners participating in one of two treatments, namely individual or couple. Method: In a study aiming to evaluate the efficacy of the Integrative Couple Treatment for Pathological Gambling (ICT-PG), couples who were entering specialized treatment for the addiction of one member who was a pathological gambler were randomly assigned to individual or ICT-PG. Nine months after their admission to treatment, gamblers and partners ( n = 21 couples; n = 13 ICT-PG; n = 8 individual treatment) were interviewed in semi-structured interviews. A sequenced thematization method was used to extract the major themes. Results: This study highlighted five major themes in the therapeutic process noted by the gamblers and their partners mainly after the couple treatment but also partly through the individual therapy. These were: (1) the gamblers' anxiety about having to reveal their gambling problems in couple therapy; (2) the wish to develop a mutually beneficial understanding of gambling and its effects on the partners in the two types of treatments; (3) the transformation of negative attributions through a more effective intra-couple communication fostered by the couple therapy; (4) the partners' contribution to changes in gambling behavior and prevention of relapses, which were both better supported in couple therapy; and (5) the interpersonal nature of gambling and its connections with the couples' relationship. However, gamblers who were in individual treatment were more likely to mention that their partners' involvement was not necessary. Participants likewise made a few recommendations about the conditions underlying the choice of one treatment method or the other. Discussion: Participants reported satisfaction with both treatment models, but their experience was more positive in couple treatment. Complementary benefits emerged from each form of treatment, which points to future treatments involving both types. Future research should explore both the couple processes associated with attempts to stop pathological gambling and the various ways of involving partners in the gamblers' treatment.

The Experience of Couples in the Process of Treatment of Pathological Gambling: Couple vs. Individual Therapy

PubMed Central

Tremblay, Joël; Dufour, Magali; Bertrand, Karine; Blanchette-Martin, Nadine; Ferland, Francine; Savard, Annie-Claude; Saint-Jacques, Marianne; Côté, Mélissa

2018-01-01

Context: Couple treatment for pathological gambling is an innovative strategy. There are some results supporting its potential effectiveness, but little is known about the subjective experiences of the participants. Objective: The aim of this article is to document the experiences of gamblers and their partners participating in one of two treatments, namely individual or couple. Method: In a study aiming to evaluate the efficacy of the Integrative Couple Treatment for Pathological Gambling (ICT-PG), couples who were entering specialized treatment for the addiction of one member who was a pathological gambler were randomly assigned to individual or ICT-PG. Nine months after their admission to treatment, gamblers and partners (n = 21 couples; n = 13 ICT-PG; n = 8 individual treatment) were interviewed in semi-structured interviews. A sequenced thematization method was used to extract the major themes. Results: This study highlighted five major themes in the therapeutic process noted by the gamblers and their partners mainly after the couple treatment but also partly through the individual therapy. These were: (1) the gamblers' anxiety about having to reveal their gambling problems in couple therapy; (2) the wish to develop a mutually beneficial understanding of gambling and its effects on the partners in the two types of treatments; (3) the transformation of negative attributions through a more effective intra-couple communication fostered by the couple therapy; (4) the partners' contribution to changes in gambling behavior and prevention of relapses, which were both better supported in couple therapy; and (5) the interpersonal nature of gambling and its connections with the couples' relationship. However, gamblers who were in individual treatment were more likely to mention that their partners' involvement was not necessary. Participants likewise made a few recommendations about the conditions underlying the choice of one treatment method or the other. Discussion: Participants reported satisfaction with both treatment models, but their experience was more positive in couple treatment. Complementary benefits emerged from each form of treatment, which points to future treatments involving both types. Future research should explore both the couple processes associated with attempts to stop pathological gambling and the various ways of involving partners in the gamblers' treatment. PMID:29416520

A molecular propeller effect for chiral separation and analysis

PubMed Central

Clemens, Jonathon B.; Kibar, Osman; Chachisvilis, Mirianas

2015-01-01

Enantiomers share nearly identical physical properties but have different chiral geometries, making their identification and separation difficult. Here we show that when exposed to a rotating electric field, the left- and right-handed chiral molecules rotate with the field and act as microscopic propellers; moreover, owing to their opposite handedness, they propel along the axis of field rotation in opposite directions. We introduce a new molecular parameter called hydrodynamic chirality to characterize the coupling of rotational motion of a chiral molecule into its translational motion and quantify the direction and velocity of such motion. We demonstrate >80% enrichment level of counterpart enantiomers in solution without using chiral selectors or circularly polarized light. We expect our results to have an impact on multiple applications in drug discovery, analytical and chiral chemistry, including determination of absolute configuration, as well as in influencing the understanding of artificial and natural molecular systems where rotational motion of the molecules is involved. PMID:26216219

A simple, broad-scope nickel(0) precatalyst system for direct amination of allyl alcohols.

PubMed

Sweeney, Joseph B; Ball, Anthony; Lawrence, Philippa; Sinclair, Mackenzie; Smith, Luke

2018-06-25

The preparation of allylic amines is traditionally accomplished by reaction of amines with reactive electrophiles, such as allylic halides, sulfonates or oxyphosphonium species; such methods involve hazardous reagents, generate stoichiometric waste streams, and often suffer from side-reactions (such as over-alkylation). We report here the first nickel-catalysed direct amination of allyl alcohols which enables allylation of primary, secondary and electron-deficient amines, using an inexpensive Ni(II)-Zn couple, without need for glove-box techniques. Under mild conditions, primary and secondary aliphatic amines react smoothly with a range of allyl alcohols, giving secondary and tertiary amines efficiently. This 'totally catalytic' method can be also applied to electron-deficient nitrogen nucleophiles with effective results; the practicality of the process has been demonstrated in an efficient, gram-scale preparation of the calcium antagonist drug substance flunarizine (Sibelium®). © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A molecular propeller effect for chiral separation and analysis

NASA Astrophysics Data System (ADS)

Clemens, Jonathon B.; Kibar, Osman; Chachisvilis, Mirianas

2015-07-01

Enantiomers share nearly identical physical properties but have different chiral geometries, making their identification and separation difficult. Here we show that when exposed to a rotating electric field, the left- and right-handed chiral molecules rotate with the field and act as microscopic propellers; moreover, owing to their opposite handedness, they propel along the axis of field rotation in opposite directions. We introduce a new molecular parameter called hydrodynamic chirality to characterize the coupling of rotational motion of a chiral molecule into its translational motion and quantify the direction and velocity of such motion. We demonstrate >80% enrichment level of counterpart enantiomers in solution without using chiral selectors or circularly polarized light. We expect our results to have an impact on multiple applications in drug discovery, analytical and chiral chemistry, including determination of absolute configuration, as well as in influencing the understanding of artificial and natural molecular systems where rotational motion of the molecules is involved.

Time-varying coupling functions: Dynamical inference and cause of synchronization transitions

NASA Astrophysics Data System (ADS)

Stankovski, Tomislav

2017-02-01

Interactions in nature can be described by their coupling strength, direction of coupling, and coupling function. The coupling strength and directionality are relatively well understood and studied, at least for two interacting systems; however, there can be a complexity in the interactions uniquely dependent on the coupling functions. Such a special case is studied here: synchronization transition occurs only due to the time variability of the coupling functions, while the net coupling strength is constant throughout the observation time. To motivate the investigation, an example is used to present an analysis of cross-frequency coupling functions between delta and alpha brain waves extracted from the electroencephalography recording of a healthy human subject in a free-running resting state. The results indicate that time-varying coupling functions are a reality for biological interactions. A model of phase oscillators is used to demonstrate and detect the synchronization transition caused by the varying coupling functions during an invariant coupling strength. The ability to detect this phenomenon is discussed with the method of dynamical Bayesian inference, which was able to infer the time-varying coupling functions. The form of the coupling function acts as an additional dimension for the interactions, and it should be taken into account when detecting biological or other interactions from data.

IBM1, a JmjC domain-containing histone demethylase, is involved in the regulation of RNA-directed DNA methylation through the epigenetic control of RDR2 and DCL3 expression in Arabidopsis

PubMed Central

Fan, Di; Dai, Yan; Wang, Xuncheng; Wang, Zhenjie; He, Hang; Yang, Hongchun; Cao, Ying; Deng, Xing Wang; Ma, Ligeng

2012-01-01

Small RNA-directed DNA methylation (RdDM) is an important epigenetic pathway in Arabidopsis that controls the expression of multiple genes and several developmental processes. RNA-DEPENDENT RNA POLYMERASE 2 (RDR2) and DICER-LIKE 3 (DCL3) are necessary factors in 24-nt small interfering RNA (siRNA) biogenesis, which is part of the RdDM pathway. Here, we found that Increase in BONSAI Methylation 1 (IBM1), a conserved JmjC family histone demethylase, is directly associated with RDR2 and DCL3 chromatin. The mutation of IBM1 induced the hypermethylation of H3K9 and DNA non-CG sites within RDR2 and DCL3, which repressed their expression. A genome-wide analysis suggested that the reduction in RDR2 and DCL3 expression affected siRNA biogenesis in a locus-specific manner and disrupted RdDM-directed gene repression. Together, our results suggest that IBM1 regulates gene expression through two distinct pathways: direct association to protect genes from silencing by preventing the coupling of histone and DNA methylation, and indirect silencing of gene expression through RdDM-directed repression. PMID:22772985

Grating-assisted surface acoustic wave directional couplers

NASA Astrophysics Data System (ADS)

Golan, G.; Griffel, G.; Seidman, A.; Croitoru, N.

1991-07-01

Physical properties of novel grating-assisted Y directional couplers are examined using the coupled-mode theory. A general formalism for the analysis of the lateral perturbed directional coupler properties is presented. Explicit expressions for waveguide key parameters such as coupling length, grating period, and other structural characterizations, are obtained. The influence of other physical properties such as time and frequency response or cutoff conditions are also analyzed. A plane grating-assisted directional coupler is presented and examined as a basic component in the integrated acoustic technology.

First example of a high-level correlated calculation of the indirect spin-spin coupling constants involving tellurium: tellurophene and divinyl telluride.

PubMed

Rusakov, Yury Yu; Krivdin, Leonid B; Østerstrøm, Freja F; Sauer, Stephan P A; Potapov, Vladimir A; Amosova, Svetlana V

2013-08-21

This paper documents the very first example of a high-level correlated calculation of spin-spin coupling constants involving tellurium taking into account relativistic effects, vibrational corrections and solvent effects for medium sized organotellurium molecules. The (125)Te-(1)H spin-spin coupling constants of tellurophene and divinyl telluride were calculated at the SOPPA and DFT levels, in good agreement with experimental data. A new full-electron basis set, av3z-J, for tellurium derived from the "relativistic" Dyall's basis set, dyall.av3z, and specifically optimized for the correlated calculations of spin-spin coupling constants involving tellurium was developed. The SOPPA method shows a much better performance compared to DFT, if relativistic effects calculated within the ZORA scheme are taken into account. Vibrational and solvent corrections are next to negligible, while conformational averaging is of prime importance in the calculation of (125)Te-(1)H spin-spin couplings. Based on the performed calculations at the SOPPA(CCSD) level, a marked stereospecificity of geminal and vicinal (125)Te-(1)H spin-spin coupling constants originating in the orientational lone pair effect of tellurium has been established, which opens a new guideline in organotellurium stereochemistry.

Direct Detection and Imaging of Low-Energy Electrons with Delta-Doped Charge-Coupled Devices

NASA Technical Reports Server (NTRS)

Nikzad, S.; Yu, Q.; Smith, A. L.; Jones, T. J.; Tombrello, T. A.; Elliott, S. T.

1998-01-01

We report the use fo delta-doped charge-coupled devices (CCDs) for direct detection of electrons in the 50-1500 eV energy range. These are the first measurements with a solid state device to detect electrons in this energy range.

75 FR 43397 - Airworthiness Directives; Piper Aircraft, Inc. Models PA-32R-301T and PA-46-350P Airplanes

Federal Register 2010, 2011, 2012, 2013, 2014

2010-07-26

... requires replacing any spot-welded, V-band exhaust coupling with a riveted, V-band exhaust coupling instead... requires replacing any spot-welded, V- band exhaust coupling with a riveted, V-band exhaust coupling...

Feasibility of antenna-to-antenna isolation measurements at S-band in the Facility for Antenna and Radar-cross-section Measurements (FARM)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brock, Billy C.

2014-01-01

Frequency-domain antenna-coupling measurements performed in the compact-range room of the FARM, will actually be dominated by reflected components from the ceiling, floor, walls, etc., not the direct freespace coupling. Consequently, signal processing must be applied to the frequency-domain data to extract the direct free-space coupling. The analysis presented above demonstrates that it is possible to do so successfully.

High resolution biomedical imaging system with direct detection of x-rays via a charge coupled device

DOEpatents

Atac, M.; McKay, T.A.

1998-04-21

An imaging system is provided for direct detection of x-rays from an irradiated biological tissue. The imaging system includes an energy source for emitting x-rays toward the biological tissue and a charge coupled device (CCD) located immediately adjacent the biological tissue and arranged transverse to the direction of irradiation along which the x-rays travel. The CCD directly receives and detects the x-rays after passing through the biological tissue. The CCD is divided into a matrix of cells, each of which individually stores a count of x-rays directly detected by the cell. The imaging system further includes a pattern generator electrically coupled to the CCD for reading a count from each cell. A display device is provided for displaying an image representative of the count read by the pattern generator from the cells of the CCD. 13 figs.

High resolution biomedical imaging system with direct detection of x-rays via a charge coupled device

DOEpatents

Atac, Muzaffer; McKay, Timothy A.

1998-01-01

An imaging system is provided for direct detection of x-rays from an irradiated biological tissue. The imaging system includes an energy source for emitting x-rays toward the biological tissue and a charge coupled device (CCD) located immediately adjacent the biological tissue and arranged transverse to the direction of irradiation along which the x-rays travel. The CCD directly receives and detects the x-rays after passing through the biological tissue. The CCD is divided into a matrix of cells, each of which individually stores a count of x-rays directly detected by the cell. The imaging system further includes a pattern generator electrically coupled to the CCD for reading a count from each cell. A display device is provided for displaying an image representative of the count read by the pattern generator from the cells of the CCD.

Direct catalytic cross-coupling of organolithium compounds

NASA Astrophysics Data System (ADS)

Giannerini, Massimo; Fañanás-Mastral, Martín; Feringa, Ben L.

2013-08-01

Catalytic carbon-carbon bond formation based on cross-coupling reactions plays a central role in the production of natural products, pharmaceuticals, agrochemicals and organic materials. Coupling reactions of a variety of organometallic reagents and organic halides have changed the face of modern synthetic chemistry. However, the high reactivity and poor selectivity of common organolithium reagents have largely prohibited their use as a viable partner in direct catalytic cross-coupling. Here we report that in the presence of a Pd-phosphine catalyst, a wide range of alkyl-, aryl- and heteroaryl-lithium reagents undergo selective cross-coupling with aryl- and alkenyl-bromides. The process proceeds quickly under mild conditions (room temperature) and avoids the notorious lithium halogen exchange and homocoupling. The preparation of key alkyl-, aryl- and heterobiaryl intermediates reported here highlights the potential of these cross-coupling reactions for medicinal chemistry and material science.

Development of a Post-Installed Deepwater Monitoring System

NASA Technical Reports Server (NTRS)

Seaman, C.; Brower, D. V.; Tang, H.; Le, S.

2015-01-01

A monitoring system that can be deployed on already existing deep water risers and flowlines has been developed. This paper describes the design concepts and testing that was performed in developing the monitoring system. A major challenge of a post-installed instrumentation system is to ensure adequate coupling is achieved between the instruments and the riser or flowline. This work investigates the sensor coupling for pipelines that are suspended in both the water column (from topside platform to the seabed) and for those that are located directly on the seabed. These different environments have resulted in two sensor attachment methods: (1) subsea adhesive sensor clamp design and (2) a friction surface sensor attachment method. This paper presents the adhesive attachment method. The monitoring elements consist of fiber optic sensors that are encased in a polyurethane clamp. With a subsea adhesive, the clamp can be installed by divers in shallow depths or by use of an ROV for deeper applications. The NASA Johnson Space Center was initially involved in the selection and testing of subsea adhesives. It was determined that up to 75 percent of the bonding strength could be achieved with the adhesive from optimal dry bonding versus bonding in submerged sea water environments. The next phase of the study involved the design, fabrication, and testing of several prototype clamps that contained the fiber optic sensors. A mold was produced by NASA using 3-D printing methods that allowed the fabrication of subscale test articles that would accommodate 4-inch and 8-inch diameter pipes. The clamps were installed with adhesive in a "wet" environment on the pipe test articles and tested in the NASA Structures Test Laboratory. The tension/compression and bending tests showed that the prototype sensor clamps achieved good coupling, and could provide high quality strain measurement for active monitoring.

20 CFR 416.432 - Change in status involving a couple; eligibility continues.

Code of Federal Regulations, 2012 CFR

2012-04-01

... dissolution of an eligible couple (for example, marriage, divorce), a redetermination of the benefit amount shall be made for the months subsequent to the month of such formation or dissolution of the couple in accordance with the following rules: (a) When there is a dissolution of an eligible couple and each member of...

20 CFR 416.432 - Change in status involving a couple; eligibility continues.

Code of Federal Regulations, 2014 CFR

2014-04-01

... dissolution of an eligible couple (for example, marriage, divorce), a redetermination of the benefit amount shall be made for the months subsequent to the month of such formation or dissolution of the couple in accordance with the following rules: (a) When there is a dissolution of an eligible couple and each member of...

HIV Risk and Protection among Gay Male Couples: The Role of Gay Community Integration

ERIC Educational Resources Information Center

Fergus, Stevenson; Lewis, Megan A.; Darbes, Lynae A.; Butterfield, Rita M.

2005-01-01

This study examined the association between different types of integration in the gay community and HIV risk among gay male couples. Previous research linking gay community integration and involvement among couples to HIV risk has been equivocal. Each partner in 59 gay couples completed a separate anonymous questionnaire that assessed two types of…

Quantifying interactions between real oscillators with information theory and phase models: application to cardiorespiratory coupling.

PubMed

Zhu, Yenan; Hsieh, Yee-Hsee; Dhingra, Rishi R; Dick, Thomas E; Jacono, Frank J; Galán, Roberto F

2013-02-01

Interactions between oscillators can be investigated with standard tools of time series analysis. However, these methods are insensitive to the directionality of the coupling, i.e., the asymmetry of the interactions. An elegant alternative was proposed by Rosenblum and collaborators [M. G. Rosenblum, L. Cimponeriu, A. Bezerianos, A. Patzak, and R. Mrowka, Phys. Rev. E 65, 041909 (2002); M. G. Rosenblum and A. S. Pikovsky, Phys. Rev. E 64, 045202 (2001)] which consists in fitting the empirical phases to a generic model of two weakly coupled phase oscillators. This allows one to obtain the interaction functions defining the coupling and its directionality. A limitation of this approach is that a solution always exists in the least-squares sense, even in the absence of coupling. To preclude spurious results, we propose a three-step protocol: (1) Determine if a statistical dependency exists in the data by evaluating the mutual information of the phases; (2) if so, compute the interaction functions of the oscillators; and (3) validate the empirical oscillator model by comparing the joint probability of the phases obtained from simulating the model with that of the empirical phases. We apply this protocol to a model of two coupled Stuart-Landau oscillators and show that it reliably detects genuine coupling. We also apply this protocol to investigate cardiorespiratory coupling in anesthetized rats. We observe reciprocal coupling between respiration and heartbeat and that the influence of respiration on the heartbeat is generally much stronger than vice versa. In addition, we find that the vagus nerve mediates coupling in both directions.

Optimal coupling to high-Q whispering gallery modes with a sub-wavelength metallic grating coupler

NASA Astrophysics Data System (ADS)

Zhou, Y.; Gu, B.; Yu, X.; Luan, F.

2015-03-01

Gold grating patterned on the end facet of an optical fiber is able to excite whispering gallery mode (WGM) in a silica microsphere. With a direct pathway of the metal reflection, the coupled WGM is able to superimpose and create an asymmetric Fano resonance. Since multiple resonances are present - the WGM, grating reflection, and a weak Fabry-Perot resonance along the diameter of the sphere - it is difficult to evaluate the power efficiency directly from the measured spectrum. Using temporal coupled-mode theory, a general model is constructed for the end-fire coupling from a grating to a WGM resonator.

Role of direct electron-phonon coupling across metal-semiconductor interfaces in thermal transport via molecular dynamics.

PubMed

Lin, Keng-Hua; Strachan, Alejandro

2015-07-21

Motivated by significant interest in metal-semiconductor and metal-insulator interfaces and superlattices for energy conversion applications, we developed a molecular dynamics-based model that captures the thermal transport role of conduction electrons in metals and heat transport across these types of interface. Key features of our model, denoted eleDID (electronic version of dynamics with implicit degrees of freedom), are the natural description of interfaces and free surfaces and the ability to control the spatial extent of electron-phonon (e-ph) coupling. Non-local e-ph coupling enables the energy of conduction electrons to be transferred directly to the semiconductor/insulator phonons (as opposed to having to first couple to the phonons in the metal). We characterize the effect of the spatial e-ph coupling range on interface resistance by simulating heat transport through a metal-semiconductor interface to mimic the conditions of ultrafast laser heating experiments. Direct energy transfer from the conduction electrons to the semiconductor phonons not only decreases interfacial resistance but also increases the ballistic transport behavior in the semiconductor layer. These results provide new insight for experiments designed to characterize e-ph coupling and thermal transport at the metal-semiconductor/insulator interfaces.

Unified model for the electromechanical coupling factor of orthorhombic piezoelectric rectangular bar with arbitrary aspect ratio

NASA Astrophysics Data System (ADS)

Rouffaud, R.; Levassort, F.; Hladky-Hennion, A.-C.

2017-02-01

Piezoelectric Single Crystals (PSC) are increasingly used in the manufacture of ultrasonic transducers and in particular for linear arrays or single element transducers. Among these PSCs, according to their microstructure and poled direction, some exhibit a mm2 symmetry. The analytical expression of the electromechanical coupling coefficient for a vibration mode along the poling direction for piezoelectric rectangular bar resonator is established. It is based on the mode coupling theory and fundamental energy ratio definition of electromechanical coupling coefficients. This unified formula for mm2 symmetry class material is obtained as a function of an aspect ratio (G) where the two extreme cases correspond to a thin plate (with a vibration mode characterized by the thickness coupling factor, kt) and a thin bar (characterized by k33'). To optimize the k33' value related to the thin bar design, a rotation of the crystallogaphic axis in the plane orthogonal to the poling direction is done to choose the highest value for PIN-PMN-PT single crystal. Finally, finite element calculations are performed to deduce resonance frequencies and coupling coefficients in a large range of G value to confirm developed analytical relations.

Vibration-Induced Errors in MEMS Tuning Fork Gyroscopes with Imbalance.

PubMed

Fang, Xiang; Dong, Linxi; Zhao, Wen-Sheng; Yan, Haixia; Teh, Kwok Siong; Wang, Gaofeng

2018-05-29

This paper discusses the vibration-induced error in non-ideal MEMS tuning fork gyroscopes (TFGs). Ideal TFGs which are thought to be immune to vibrations do not exist, and imbalance between two gyros of TFGs is an inevitable phenomenon. Three types of fabrication imperfections (i.e., stiffness imbalance, mass imbalance, and damping imbalance) are studied, considering different imbalance radios. We focus on the coupling types of two gyros of TFGs in both drive and sense directions, and the vibration sensitivities of four TFG designs with imbalance are simulated and compared. It is found that non-ideal TFGs with two gyros coupled both in drive and sense directions (type CC TFGs) are the most insensitive to vibrations with frequencies close to the TFG operating frequencies. However, sense-axis vibrations with in-phase resonant frequencies of a coupled gyros system result in severe error outputs to TFGs with two gyros coupled in the sense direction, which is mainly attributed to the sense capacitance nonlinearity. With increasing stiffness coupled ratio of the coupled gyros system, the sensitivity to vibrations with operating frequencies is cut down, yet sensitivity to vibrations with in-phase frequencies is amplified.

Directed and persistent movement arises from mechanochemistry of the ParA/ParB system

PubMed Central

Hu, Longhua; Vecchiarelli, Anthony G.; Mizuuchi, Kiyoshi; Neuman, Keir C.; Liu, Jian

2015-01-01

The segregation of DNA before cell division is essential for faithful genetic inheritance. In many bacteria, segregation of low-copy number plasmids involves an active partition system composed of a nonspecific DNA-binding ATPase, ParA, and its stimulator protein ParB. The ParA/ParB system drives directed and persistent movement of DNA cargo both in vivo and in vitro. Filament-based models akin to actin/microtubule-driven motility were proposed for plasmid segregation mediated by ParA. Recent experiments challenge this view and suggest that ParA/ParB system motility is driven by a diffusion ratchet mechanism in which ParB-coated plasmid both creates and follows a ParA gradient on the nucleoid surface. However, the detailed mechanism of ParA/ParB-mediated directed and persistent movement remains unknown. Here, we develop a theoretical model describing ParA/ParB-mediated motility. We show that the ParA/ParB system can work as a Brownian ratchet, which effectively couples the ATPase-dependent cycling of ParA–nucleoid affinity to the motion of the ParB-bound cargo. Paradoxically, this resulting processive motion relies on quenching diffusive plasmid motion through a large number of transient ParA/ParB-mediated tethers to the nucleoid surface. Our work thus sheds light on an emergent phenomenon in which nonmotor proteins work collectively via mechanochemical coupling to propel cargos—an ingenious solution shaped by evolution to cope with the lack of processive motor proteins in bacteria. PMID:26647183

Couples Counseling Directive Technique: A (Mis)communication Model to Promote Insight, Catharsis, Disclosure, and Problem Resolution

ERIC Educational Resources Information Center

Mahaffey, Barbara A.

2010-01-01

A psychoeducational model for improving couple communication is proposed. An important goal in couples counseling is to assist couples in resolving communication conflicts. The proposed communication model helps to establish a therapeutic environment that encourages insight, therapeutic alliance formation, catharsis, self-disclosure, symptom…

Search for pair production of third-generation scalar leptoquarks and top squarks in proton–proton collisions at $$\\sqrt{s}$$=8 TeV

DOE PAGES

Khachatryan, Vardan

2014-10-30

A search for pair production of third-generation scalar leptoquarks and supersymmetric top quark partners, top squarks, in final states involving tau leptons and bottom quarks is presented. The search uses events from a data sample of proton–proton collisions corresponding to an integrated luminosity of 19.7 fb -1, collected with the CMS detector at the LHC with . The number of observed events is found to be in agreement with the expected standard model background. Third-generation scalar leptoquarks with masses below 740 GeV are excluded at 95% confidence level, assuming a 100% branching fraction for the leptoquark decay to a taumore » lepton and a bottom quark. In addition, this mass limit applies directly to top squarks decaying via an R-parity violating coupling . The search also considers a similar signature from top squarks undergoing a chargino-mediated decay involving the R-parity violating coupling. Each top squark decays to a tau lepton, a bottom quark, and two light quarks. Top squarks in this model with masses below 580 GeV are excluded at 95% confidence level. The constraint on the leptoquark mass is the most stringent to date, and this is the first search for top squarks decaying via λ' 3jk .« less

Coevolving residues of (beta/alpha)(8)-barrel proteins play roles in stabilizing active site architecture and coordinating protein dynamics.

PubMed

Shen, Hongbo; Xu, Feng; Hu, Hairong; Wang, Feifei; Wu, Qi; Huang, Qiang; Wang, Honghai

2008-12-01

Indole-3-glycerol phosphate synthase (IGPS) is a representative of (beta/alpha)(8)-barrel proteins-the most common enzyme fold in nature. To better understand how the constituent amino-acids work together to define the structure and to facilitate the function, we investigated the evolutionary and dynamical coupling of IGPS residues by combining statistical coupling analysis (SCA) and molecular dynamics (MD) simulations. The coevolving residues identified by the SCA were found to form a network which encloses the active site completely. The MD simulations showed that these coevolving residues are involved in the correlated and anti-correlated motions. The correlated residues are within van der Waals contact and appear to maintain the active site architecture; the anti-correlated residues are mainly distributed on opposite sides of the catalytic cavity and coordinate the motions likely required for the substrate entry and product release. Our findings might have broad implications for proteins with the highly conserved (betaalpha)(8)-barrel in assessing the roles of amino-acids that are moderately conserved and not directly involved in the active site of the (beta/alpha)(8)-barrel. The results of this study could also provide useful information for further exploring the specific residue motions for the catalysis and protein design based on the (beta/alpha)(8)-barrel scaffold.

G protein-coupled receptor 30 contributes to improved remyelination after cuprizone-induced demyelination.

PubMed

Hirahara, Yukie; Matsuda, Ken Ichi; Yamada, Hisao; Saitou, Akira; Morisaki, Shinsuke; Takanami, Keiko; Boggs, Joan M; Kawata, Mitsuhiro

2013-03-01

Estrogen exerts neuroprotective and promyelinating actions. The therapeutic effect has been shown in animal models of multiple sclerosis, in which the myelin sheath is specifically destroyed in the central nervous system. However, it remains unproven whether estrogen is directly involved in remyelination via the myelin producing cells, oligodendrocytes, or which estrogen receptors are involved. In this study, we found that the membrane-associated estrogen receptor, the G protein-coupled receptor 30 (GPR30), also known as GPER, was expressed in oligodendrocytes in rat spinal cord and corpus callosum. Moreover, GPR30 was expressed throughout oligodendrocyte differentiation and promyelinating stages in primary oligodendrocyte cultures derived from rat spinal cords and brains. To evaluate the role of signaling via GPR30 in promyelination, a specific agonist for GPR30, G1, was administered to a rat model of demyelination induced by cuprizone treatment. Histological examination of the corpus callosum with oligodendrocyte differentiation stage-specific markers showed that G1 enhanced oligodendrocyte maturation in corpus callosum of cuprizone-treated animals. It also enhanced oligodendrocyte ensheathment of dorsal root ganglion (DRG) neurons in co-culture and myelination in cuprizone-treated animals. This study is the first evidence that GPR30 signaling promotes remyelination by oligodendrocytes after demyelination. GPR30 ligands may provide a novel therapy for the treatment of multiple sclerosis. Copyright © 2012 Wiley Periodicals, Inc.

Renal sympathetic nerve, blood flow, and epithelial transport responses to thermal stress.

PubMed

Wilson, Thad E

2017-05-01

Thermal stress is a profound sympathetic stress in humans; kidney responses involve altered renal sympathetic nerve activity (RSNA), renal blood flow, and renal epithelial transport. During mild cold stress, RSNA spectral power but not total activity is altered, renal blood flow is maintained or decreased, and epithelial transport is altered consistent with a sympathetic stress coupled with central volume loaded state. Hypothermia decreases RSNA, renal blood flow, and epithelial transport. During mild heat stress, RSNA is increased, renal blood flow is decreased, and epithelial transport is increased consistent with a sympathetic stress coupled with a central volume unloaded state. Hyperthermia extends these directional changes, until heat illness results. Because kidney responses are very difficult to study in humans in vivo, this review describes and qualitatively evaluates an in vivo human skin model of sympathetically regulated epithelial tissue compared to that of the nephron. This model utilizes skin responses to thermal stress, involving 1) increased skin sympathetic nerve activity (SSNA), decreased skin blood flow, and suppressed eccrine epithelial transport during cold stress; and 2) increased SSNA, skin blood flow, and eccrine epithelial transport during heat stress. This model appears to mimic aspects of the renal responses. Investigations of skin responses, which parallel certain renal responses, may aid understanding of epithelial-sympathetic nervous system interactions during cold and heat stress. Copyright © 2016 Elsevier B.V. All rights reserved.

Physiology and Evolution of Voltage-Gated Calcium Channels in Early Diverging Animal Phyla: Cnidaria, Placozoa, Porifera and Ctenophora

PubMed Central

Senatore, Adriano; Raiss, Hamad; Le, Phuong

2016-01-01

Voltage-gated calcium (Cav) channels serve dual roles in the cell, where they can both depolarize the membrane potential for electrical excitability, and activate transient cytoplasmic Ca2+ signals. In animals, Cav channels play crucial roles including driving muscle contraction (excitation-contraction coupling), gene expression (excitation-transcription coupling), pre-synaptic and neuroendocrine exocytosis (excitation-secretion coupling), regulation of flagellar/ciliary beating, and regulation of cellular excitability, either directly or through modulation of other Ca2+-sensitive ion channels. In recent years, genome sequencing has provided significant insights into the molecular evolution of Cav channels. Furthermore, expanded gene datasets have permitted improved inference of the species phylogeny at the base of Metazoa, providing clearer insights into the evolution of complex animal traits which involve Cav channels, including the nervous system. For the various types of metazoan Cav channels, key properties that determine their cellular contribution include: Ion selectivity, pore gating, and, importantly, cytoplasmic protein-protein interactions that direct sub-cellular localization and functional complexing. It is unclear when these defining features, many of which are essential for nervous system function, evolved. In this review, we highlight some experimental observations that implicate Cav channels in the physiology and behavior of the most early-diverging animals from the phyla Cnidaria, Placozoa, Porifera, and Ctenophora. Given our limited understanding of the molecular biology of Cav channels in these basal animal lineages, we infer insights from better-studied vertebrate and invertebrate animals. We also highlight some apparently conserved cellular functions of Cav channels, which might have emerged very early on during metazoan evolution, or perhaps predated it. PMID:27867359

[Excitation-contraction coupling in skeletal muscle: questions remaining after 50 years of research].

PubMed

Calderón-Vélez, Juan Camilo; Figueroa-Gordon, Lourdes Carolina

2009-03-01

The excitation-contraction coupling mechanism was defined as the entire sequence of reactions linking excitation of plasma membrane to activation of contraction in skeletal muscle. By using different techniques, their regulation and interactions have been studied during the last 50 years, defining until now the importance and origin of the calcium ion as a contractile activator and the main proteins involved in the whole mechanism. Furthermore, the study of the ultrastructural basis and pharmacological regulation of the excitation-contraction coupling phenomenon has begun. The excitation-contraction coupling is thought to be altered in situations as ageing, muscle fatigue and some muscle diseases. However, many questions remain to be answered. For example, (1) How excitation-contraction coupling develops and ages? (2) What role does it play in muscle fatigue and other diseases? (3) What is the nature of the interaction between the proteins believed to be involved? The present review describes excitation-contraction coupling in skeletal muscle and techniques used to better understand it as an introduction for discussing unanswered questions regarding excitation-contraction coupling.

Neuron-glia metabolic coupling and plasticity.

PubMed

Magistretti, Pierre J

2006-06-01

The coupling between synaptic activity and glucose utilization (neurometabolic coupling) is a central physiological principle of brain function that has provided the basis for 2-deoxyglucose-based functional imaging with positron emission tomography (PET). Astrocytes play a central role in neurometabolic coupling, and the basic mechanism involves glutamate-stimulated aerobic glycolysis; the sodium-coupled reuptake of glutamate by astrocytes and the ensuing activation of the Na-K-ATPase triggers glucose uptake and processing via glycolysis, resulting in the release of lactate from astrocytes. Lactate can then contribute to the activity-dependent fuelling of the neuronal energy demands associated with synaptic transmission. An operational model, the 'astrocyte-neuron lactate shuttle', is supported experimentally by a large body of evidence, which provides a molecular and cellular basis for interpreting data obtained from functional brain imaging studies. In addition, this neuron-glia metabolic coupling undergoes plastic adaptations in parallel with adaptive mechanisms that characterize synaptic plasticity. Thus, distinct subregions of the hippocampus are metabolically active at different time points during spatial learning tasks, suggesting that a type of metabolic plasticity, involving by definition neuron-glia coupling, occurs during learning. In addition, marked variations in the expression of genes involved in glial glycogen metabolism are observed during the sleep-wake cycle, with in particular a marked induction of expression of the gene encoding for protein targeting to glycogen (PTG) following sleep deprivation. These data suggest that glial metabolic plasticity is likely to be concomitant with synaptic plasticity.

Solid state rapid thermocycling

DOEpatents

Beer, Neil Reginald; Spadaccini, Christopher

2014-05-13

The rapid thermal cycling of a material is targeted. A solid state heat exchanger with a first well and second well is coupled to a power module. A thermoelectric element is coupled to the first well, the second well, and the power module, is configured to transfer thermal energy from the first well to the second well when current from the power module flows through the thermoelectric element in a first direction, and is configured to transfer thermal energy from the second well to the first well when current from the power module flows through the thermoelectric element in a second direction. A controller may be coupled to the thermoelectric elements, and may switch the direction of current flowing through the thermoelectric element in response to a determination by sensors coupled to the wells that the amount of thermal energy in the wells falls below or exceeds a pre-determined threshold.

Sliding mode control of direct coupled interleaved boost converter for fuel cell

NASA Astrophysics Data System (ADS)

Wang, W. Y.; Ding, Y. H.; Ke, X.; Ma, X.

2017-12-01

A three phase direct coupled interleaved boost converter (TP-DIBC) was recommended in this paper. This converter has a small unbalance current sharing among the branches of TP-DIBC. An adaptive control law sliding mode control (SMC) is designed for the TP-DIBC. The aim is to 1) reduce ripple output voltage, inductor current and regulate output voltage tightly 2) The total current carried by direct coupled interleaved boost converter (DIBC) must be equally shared between different parallel branches. The efficacy and robustness of the proposed TP-DIBC and adaptive SMC is confirmed via computer simulations using Matlab SimPower System Tools. The simulation result is in line with the expectation.

Dynamics of a minimal consumer network with bi-directional influence

NASA Astrophysics Data System (ADS)

Ekaterinchuk, Ekaterina; Jungeilges, Jochen; Ryazanova, Tatyana; Sushko, Iryna

2018-05-01

We study the dynamics of a model of interdependent consumer behavior defined by a family of two-dimensional noninvertible maps. This family belongs to a class of coupled logistic maps with different nonlinearity parameters and coupling terms that depend on one variable only. In our companion paper we considered the case of independent consumers as well as the case of uni-directionally connected consumers. The present paper aims at describing the dynamics in the case of a bi-directional connection. In particular, we investigate the bifurcation structure of the parameter plane associated with the strength of coupling between the consumers, focusing on the mechanisms of qualitative transformations of coexisting attractors and their basins of attraction.

Direct Determinations of the πNN Coupling Constants

NASA Astrophysics Data System (ADS)

Ericson, T. E. O.; Loiseau, B.

1998-11-01

A novel extrapolation method has been used to deduce directly the charged πN N coupling constant from backward np differential scattering cross sections. The extracted value, g2c = 14.52(0.26) is higher than the indirectly deduced values obtained in nucleon-nucleon energy-dependent partial-wave analyses. Our preliminary direct value from a reanalysis of the GMO sum-rule points to an intermediate value of g2c about 13.97(30).

Canadian mock juror attitudes and decisions in domestic violence cases involving asian and white interracial and intraracial couples.

PubMed

Maeder, Evelyn M; Mossière, Annik; Cheung, Liann

2013-03-01

This study manipulated the race of the defendant and the victim (White/White, White/Asian, Asian/Asian, and Asian/White) in a domestic violence case to examine the potential prejudicial impact of race on juror decision making. A total of 181 undergraduate students read a trial transcript involving an allegation of spousal abuse in which defendant and victim race were manipulated using photographs. They then provided a verdict and confidence rating, a sentence, and responsibility attributions, and completed various scales measuring attitudes toward wife abuse and women. Findings revealed that female jurors were harsher toward the defendant than were male jurors. When controlling for attitudes toward Asians, jurors found the defendant guilty more often in cases involving interracial couples, as compared to same-race couples. Path analyses revealed various factors and attitudes involved in domestic violence trial outcomes. Findings contribute to the scarce literature on legal proceedings involving Asians, particularly in domestic violence cases. Outcomes also provide a model for relevant factors and characteristics of jurors in domestic violence cases. Roadblocks inherent in jury research are also discussed.

Nickel-catalyzed cross-coupling of photoredox-generated radicals: uncovering a general manifold for stereoconvergence in nickel-catalyzed cross-couplings.

PubMed

Gutierrez, Osvaldo; Tellis, John C; Primer, David N; Molander, Gary A; Kozlowski, Marisa C

2015-04-22

The cross-coupling of sp(3)-hybridized organoboron reagents via photoredox/nickel dual catalysis represents a new paradigm of reactivity for engaging alkylmetallic reagents in transition-metal-catalyzed processes. Reported here is an investigation into the mechanistic details of this important transformation using density functional theory. Calculations bring to light a new reaction pathway involving an alkylnickel(I) complex generated by addition of an alkyl radical to Ni(0) that is likely to operate simultaneously with the previously proposed mechanism. Analysis of the enantioselective variant of the transformation reveals an unexpected manifold for stereoinduction involving dynamic kinetic resolution (DKR) of a Ni(III) intermediate wherein the stereodetermining step is reductive elimination. Furthermore, calculations suggest that the DKR-based stereoinduction manifold may be responsible for stereoselectivity observed in numerous other stereoconvergent Ni-catalyzed cross-couplings and reductive couplings.

Regioselective Cu(I)-catalyzed tandem A3-coupling/decarboxylative coupling to 3-amino-1,4-enynes.

PubMed

Feng, Huangdi; Ermolat'ev, Denis S; Song, Gonghua; Van der Eycken, Erik V

2012-04-06

An efficient and novel copper-mediated protocol for the synthesis of 3-amino-1,4-enynes from glyoxylic acid, an amine, and an alkyne was developed. This new reaction involving two sequential C-C bond formations is air and moisture tolerant and proceeds via a tandem A(3)-coupling and a selective decarboxylative coupling.

QUINONE METHIDES IN LIGNIFICATION

USDA-ARS?s Scientific Manuscript database

Quinone methides play an important role in lignification. They are produced directly, as intermediates, when lignin monomers, be they hydroxycinnamyl alcohols, hydroxycinnamaldehydes, or hydroxycinnamates, couple or cross-couple at their 8-positions. A variety of post-coupling quinone methide rearom...

The Sedimentation of Particles under Orthogonal Shear in Viscoelastic Fluids

NASA Astrophysics Data System (ADS)

Murch, William L.; Krishnan, Sreenath; Shaqfeh, Eric S. G.

2016-11-01

Many engineering applications, including oil and gas recovery, require the suspension of particles in viscoelastic fluids during fluid transport and processing. A topic of specific importance involves such particle suspensions experiencing an applied shear flow in a direction perpendicular to gravity (referred to as orthogonal shear). Previously, it has been shown that particle sedimentation coupled with an orthogonal shear flow can reduce the particle settling rate in elastic fluids. The underlying mechanism of this enhanced coupling drag is not fully understood, particularly at finite Weissenberg numbers. This talk examines the role of fluid elasticity on a single, non-Brownian, rigid sphere settling in orthogonal shear using experiments and numerical simulations. New experiments were performed in a Taylor-Couette flow cell using Boger fluids to study the coupling drag as a function of the shear and sedimentation Weissenberg numbers as well as particle confinement. The elastic effect was also studied with fully 3D simulations of flow past a rigid sphere, using the FENE-P constitutive model to describe the polymeric fluid rheology. These simulations show good agreement with the experiments and allow for further insight into the mechanism of elasticity-enhanced drag. This material is based upon work supported by the National Science Foundation Graduate Research Fellowship.

Accuracy and projection in perceptions of partners' recent emotional experiences: Both minds matter.

PubMed

Clark, Margaret S; Von Culin, Katherine R; Clark-Polner, Elizabeth; Lemay, Edward P

2017-03-01

In 2 studies involving 96 married couples (Study 1) and 118 romantic couples (Study 2), we investigated partners' perceptions of each others' recently experienced emotions. In both studies, both individuals within each couple independently provided reports of (a) their own recently experienced emotions, (b) their perceptions of their partners' recently experienced emotions, and (c) the extent to which they had expressed the emotions they had experienced to their partner. We then assessed the extent to which perceptions of partners' emotions were (a) accurate (i.e., in agreement with partners' independent reports of their own feelings) and (b) a function of the perceiver's own emotions (i.e., projected). Significant evidence for both accuracy in perceiving emotions (4 of 7 emotions in Study 1; 8 of 9 emotions in Study 2) and for projection of perceivers' own emotions onto partners was obtained (5 of 7 emotions in Study 1; 9 of 9 emotions in Study 2). Effects for all remaining emotions trended in the same directions. There was almost no moderation of these effects by targets' having knowingly expressed the emotions. Implications of the patterning of findings for different emotions for the social functions of accuracy and projection in perceiving emotions are discussed. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Engineering magnetism at functional oxides interfaces: manganites and beyond

NASA Astrophysics Data System (ADS)

Yi, Di; Lu, Nianpeng; Chen, Xuegang; Shen, Shengchun; Yu, Pu

2017-11-01

The family of transition metal oxides (TMOs) is a large class of magnetic materials that has been intensively studied due to the rich physics involved as well as the promising potential applications in next generation electronic devices. In TMOs, the spin, charge, orbital and lattice are strongly coupled, and significant advances have been achieved to engineer the magnetism by different routes that manipulate these degrees of freedom. The family of manganites is a model system of strongly correlated magnetic TMOs. In this review, using manganites thin films and the heterostructures in conjunction with other TMOs as model systems, we review the recent progress of engineering magnetism in TMOs. We first discuss the role of the lattice that includes the epitaxial strain and the interface structural coupling. Then we look into the role of charge, focusing on the interface charge modulation. Having demonstrated the static effects, we continue to review the research on dynamical control of magnetism by electric field. Next, we review recent advances in heterostructures comprised of high T c cuprate superconductors and manganites. Following that, we discuss the emergent magnetic phenomena at interfaces between 3d TMOs and 5d TMOs with strong spin-orbit coupling. Finally, we provide our outlook for prospective future directions.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Adam, J. C.; Stephens, J. C.; Chung, Serena

As managers of agricultural and natural resources are confronted with uncertainties in global change impacts, the complexities associated with the interconnected cycling of nitrogen, carbon, and water present daunting management challenges. Existing models provide detailed information on specific sub-systems (land, air, water, economics, etc). An increasing awareness of the unintended consequences of management decisions resulting from interconnectedness of these sub-systems, however, necessitates coupled regional earth system models (EaSMs). Decision makers’ needs and priorities can be integrated into the model design and development processes to enhance decision-making relevance and "usability" of EaSMs. BioEarth is a current research initiative with a focusmore » on the U.S. Pacific Northwest region that explores the coupling of multiple stand-alone EaSMs to generate usable information for resource decision-making. Direct engagement between model developers and non-academic stakeholders involved in resource and environmental management decisions throughout the model development process is a critical component of this effort. BioEarth utilizes a "bottom-up" approach, upscaling a catchment-scale model to basin and regional scales, as opposed to the "top-down" approach of downscaling global models utilized by most other EaSM efforts. This paper describes the BioEarth initiative and highlights opportunities and challenges associated with coupling multiple stand-alone models to generate usable information for agricultural and natural resource decision-making.« less

Gap junctions between CA3 pyramidal cells contribute to network synchronization in neonatal hippocampus.

PubMed

Molchanova, Svetlana M; Huupponen, Johanna; Lauri, Sari E; Taira, Tomi

2016-08-01

Direct electrical coupling between neurons through gap junctions is prominent during development, when synaptic connectivity is scarce, providing the additional intercellular connectivity. However, functional studies of gap junctions are hampered by the unspecificity of pharmacological tools available. Here we have investigated gap-junctional coupling between CA3 pyramidal cells in neonatal hippocampus and its contribution to early network activity. Four different gap junction inhibitors, including the general blocker carbenoxolone, decreased the frequency of network activity bursts in CA3 area of hippocampus of P3-6 rats, suggesting the involvement of electrical connections in the generation of spontaneous network activity. In CA3 pyramidal cells, spikelets evoked by local stimulation of stratum oriens, were inhibited by carbenoxolone, but not by inhibitors of glutamatergic and GABAergic synaptic transmission, signifying the presence of electrical connectivity through axo-axonic gap junctions. Carbenoxolone also decreased the success rate of firing antidromic action potentials in response to stimulation, and changed the pattern of spontaneous action potential firing of CA3 pyramidal cells. Altogether, these data suggest that electrical coupling of CA3 pyramidal cells contribute to the generation of the early network events in neonatal hippocampus by modulating their firing pattern and synchronization. Copyright © 2016 Elsevier Ltd. All rights reserved.

The rise and fall of civil unions: lessons from the Connecticut legislature's abandonment of gay and lesbian citizens.

PubMed

Thomas, Susan L

2011-01-01

On April 20, 2005, Connecticut Governor M. Jodi Rell signed into law "An Act Concerning Civil Unions" (Public Act No. 05-10, 2005). That Act did two things: First, it afforded to qualifying same-sex couples many of the rights and benefits that the state makes available to married heterosexual couples. Second, it "defended" heterosexual marriage by defining marriage as involving one man and one woman. Although it might seem that the legislature was moving in an obviously correct direction, its decision to establish a statutory scheme consigning same-sex couples to civil unions was integral to the ideological exclusion of gays and lesbians from marriage and, thereby, implied that they are unfit for family life. The Democrats' and Republicans' focus was on the formal equality guaranteed by the civil union legislation. But the heart of the legislation is disenfranchisement. Connecticut lawmakers placed the stamp of legitimacy on a policy that officially excluded lesbians and gays from full membership in civil society. To many gay and lesbian citizens in Connecticut, it was a slap in the face and awakened a realization that lawmakers' professed egalitarian ideals and the realities of defining who belonged to their communities may not coincide.

Vector magnetometer based on synchronous manipulation of nitrogen-vacancy centers in all crystal directions

NASA Astrophysics Data System (ADS)

Zhang, Chen; Yuan, Heng; Zhang, Ning; Xu, Lixia; Zhang, Jixing; Li, Bo; Fang, Jiancheng

2018-04-01

Negatively charged nitrogen vacancy (NV‑) centers in diamond have been extensively studied as high-sensitivity magnetometers, showcasing a wide range of applications. This study experimentally demonstrates a vector magnetometry scheme based on synchronous manipulation of NV‑ center ensembles in all crystal directions using double frequency microwaves (MWs) and multi-coupled-strip-lines (mCSL) waveguide. The application of the mCSL waveguide ensures a high degree of synchrony (99%) for manipulating NV‑ centers in multiple orientations in a large volume. Manipulation with double frequency MWs makes NV‑ centers of all four crystal directions involved, and additionally leads to an enhancement of the manipulation field. In this work, by monitoring the changes in the slope of the resonance line consisting of multi-axes NV‑ centers, measurement of the direction of the external field vector was demonstrated with a sensitivity of {{10}\\prime}/\\sqrt{Hz} . Based on the scheme, the fluorescence signal contrast was improved by four times higher and the sensitivity to the magnetic field strength was improved by two times. The method provides a more practical way of achieving vector sensors based on NV‑ center ensembles in diamond.

Neural Responses to Heartbeats in the Default Network Encode the Self in Spontaneous Thoughts.

PubMed

Babo-Rebelo, Mariana; Richter, Craig G; Tallon-Baudry, Catherine

2016-07-27

The default network (DN) has been consistently associated with self-related cognition, but also to bodily state monitoring and autonomic regulation. We hypothesized that these two seemingly disparate functional roles of the DN are functionally coupled, in line with theories proposing that selfhood is grounded in the neural monitoring of internal organs, such as the heart. We measured with magnetoencephalograhy neural responses evoked by heartbeats while human participants freely mind-wandered. When interrupted by a visual stimulus at random intervals, participants scored the self-relatedness of the interrupted thought. They evaluated their involvement as the first-person perspective subject or agent in the thought ("I"), and on another scale to what degree they were thinking about themselves ("Me"). During the interrupted thought, neural responses to heartbeats in two regions of the DN, the ventral precuneus and the ventromedial prefrontal cortex, covaried, respectively, with the "I" and the "Me" dimensions of the self, even at the single-trial level. No covariation between self-relatedness and peripheral autonomic measures (heart rate, heart rate variability, pupil diameter, electrodermal activity, respiration rate, and phase) or alpha power was observed. Our results reveal a direct link between selfhood and neural responses to heartbeats in the DN and thus directly support theories grounding selfhood in the neural monitoring of visceral inputs. More generally, the tight functional coupling between self-related processing and cardiac monitoring observed here implies that, even in the absence of measured changes in peripheral bodily measures, physiological and cognitive functions have to be considered jointly in the DN. The default network (DN) has been consistently associated with self-processing but also with autonomic regulation. We hypothesized that these two functions could be functionally coupled in the DN, inspired by theories according to which selfhood is grounded in the neural monitoring of internal organs. Using magnetoencephalography, we show that heartbeat-evoked responses (HERs) in the DN covary with the self-relatedness of ongoing spontaneous thoughts. HER amplitude in the ventral precuneus covaried with the "I" self-dimension, whereas HER amplitude in the ventromedial prefrontal cortex encoded the "Me" self-dimension. Our experimental results directly support theories rooting selfhood in the neural monitoring of internal organs. We propose a novel functional framework for the DN, where self-processing is coupled with physiological monitoring. Copyright © 2016 Babo-Rebelo et al.

Neural Responses to Heartbeats in the Default Network Encode the Self in Spontaneous Thoughts

PubMed Central

Babo-Rebelo, Mariana; Richter, Craig G.

2016-01-01

The default network (DN) has been consistently associated with self-related cognition, but also to bodily state monitoring and autonomic regulation. We hypothesized that these two seemingly disparate functional roles of the DN are functionally coupled, in line with theories proposing that selfhood is grounded in the neural monitoring of internal organs, such as the heart. We measured with magnetoencephalograhy neural responses evoked by heartbeats while human participants freely mind-wandered. When interrupted by a visual stimulus at random intervals, participants scored the self-relatedness of the interrupted thought. They evaluated their involvement as the first-person perspective subject or agent in the thought (“I”), and on another scale to what degree they were thinking about themselves (“Me”). During the interrupted thought, neural responses to heartbeats in two regions of the DN, the ventral precuneus and the ventromedial prefrontal cortex, covaried, respectively, with the “I” and the “Me” dimensions of the self, even at the single-trial level. No covariation between self-relatedness and peripheral autonomic measures (heart rate, heart rate variability, pupil diameter, electrodermal activity, respiration rate, and phase) or alpha power was observed. Our results reveal a direct link between selfhood and neural responses to heartbeats in the DN and thus directly support theories grounding selfhood in the neural monitoring of visceral inputs. More generally, the tight functional coupling between self-related processing and cardiac monitoring observed here implies that, even in the absence of measured changes in peripheral bodily measures, physiological and cognitive functions have to be considered jointly in the DN. SIGNIFICANCE STATEMENT The default network (DN) has been consistently associated with self-processing but also with autonomic regulation. We hypothesized that these two functions could be functionally coupled in the DN, inspired by theories according to which selfhood is grounded in the neural monitoring of internal organs. Using magnetoencephalography, we show that heartbeat-evoked responses (HERs) in the DN covary with the self-relatedness of ongoing spontaneous thoughts. HER amplitude in the ventral precuneus covaried with the “I” self-dimension, whereas HER amplitude in the ventromedial prefrontal cortex encoded the “Me” self-dimension. Our experimental results directly support theories rooting selfhood in the neural monitoring of internal organs. We propose a novel functional framework for the DN, where self-processing is coupled with physiological monitoring. PMID:27466329

Roughness measurements on coupling structures for optical interconnections integrated on a printed circuit board

NASA Astrophysics Data System (ADS)

Hendrickx, Nina; Van Erps, Jürgen; Suyal, Himanshu; Taghizadeh, Mohammad; Thienpont, Hugo; Van Daele, Peter

2006-04-01

In this paper, laser ablation (at UGent), deep proton writing (at VUB) and laser direct writing (at HWU) are presented as versatile technologies that can be used for the fabrication of coupling structures for optical interconnections integrated on a printed circuit board (PCB). The optical layer, a highly cross-linked acrylate based polymer, is applied on an FR4 substrate. Both laser ablation and laser direct writing are used for the definition of arrays of multimode optical waveguides, which guide the light in the plane of the optical layer. In order to couple light vertically in/out of the plane of the optical waveguides, coupling structures have to be integrated into the optical layer. Out-of-plane turning mirrors, that deflect the light beam over 90°, are used for this purpose. The surface roughness and angle of three mirror configurations are evaluated: a laser ablated one that is integrated into the optical waveguide, a laser direct written one that is also directly written onto the waveguide and a DPW insert that is plugged into a cavity into the waveguiding layer.

Apparatus for supplying conditioned air at a substantially constant temperature and humidity

NASA Technical Reports Server (NTRS)

Obler, H. D. (Inventor)

1980-01-01

The apparatus includes a supply duct coupled to a source of supply air for carrying the supply air therethrough. A return duct is coupled to the supply duct for carrying return conditioned air therethrough. A temperature reducing device is coupled to the supply duct for decreasing the temperature of the supply and return conditioned air. A by-pass duct is coupled to the supply duct for selectively directing portions of the supply and return conditioned air around the temperature reducing device. Another by-pass duct is coupled to the return duct for selectively directing portions of the return conditioned air around the supply duct and the temperature reduction device. Controller devices selectively control the flow and amount of mixing of the supply and return conditioned air.

Directional multimode coupler for planar magnonics: Side-coupled magnetic stripes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sadovnikov, A. V., E-mail: sadovnikovav@gmail.com; Nikitov, S. A.; Kotel'nikov Institute of Radioengineering and Electronics, Russian Academy of Sciences, Moscow 125009

We experimentally demonstrate spin waves coupling in two laterally adjacent magnetic stripes. By the means of Brillouin light scattering spectroscopy, we show that the coupling efficiency depends both on the magnonic waveguides' geometry and the characteristics of spin-wave modes. In particular, the lateral confinement of coupled yttrium-iron-garnet stripes enables the possibility of control over the spin-wave propagation characteristics. Numerical simulations (in time domain and frequency domain) reveal the nature of intermodal coupling between two magnonic stripes. The proposed topology of multimode magnonic coupler can be utilized as a building block for fabrication of integrated parallel functional and logic devices suchmore » as the frequency selective directional coupler or tunable splitter, enabling a number of potential applications for planar magnonics.« less

Ethical issues involved with in vitro fertilization.

PubMed

Shannon, T A

1990-09-01

There are three elements to consider with in vitro fertilization. First, the paramount concern needs to be the well-being and best interests of the child, even though he or she may be an embryo at the time. Second, some people think a child will solve their marital problems. Although couples seeking in vitro fertilization should not be subjected to more scrutiny than couples conceiving in the traditional way, the stresses and uncertainties of in vitro fertilization can further strain a marriage. Clinic staff members should be sensitive to this issue as a way of helping to avoid complications later. Third, how we resolve the status and fate of the frozen embryo and who has disposition over it surely will reflect how we consider abortion rights. For example, if the standards of Roe vs Wade were applied, one could argue that the woman should have total disposition over the frozen embryo. On the other hand, if the father receives a say in the matter, what impact would this have? Given the nature of our society and the tenuous state of marriage, the problem of disposing frozen embryos is a critical one that has no satisfactory solution. Finally, there is the stress factor. Although this is not an issue of direct ethical concern, it is related to the necessity of the couple receiving accurate information. If the couple receives an incorrect impression of a clinic's success rates, they may be exposed unnecessarily to further stress and frustration.(ABSTRACT TRUNCATED AT 250 WORDS)

Whose intentions predict? Power over condom use within heterosexual dyads.

PubMed

VanderDrift, Laura E; Agnew, Christopher R; Harvey, S Marie; Warren, Jocelyn T

2013-10-01

According to major theories of behavioral prediction, the most proximal psychological predictor of an individual's behavior is that individual's intention. With respect to interdependent behaviors such as condom use, however, relationship dynamics influence individuals' power to make decisions and to act. The current study examines how relationship dynamics impact 3 condom use relevant outcomes: (a) the individual forming his or her own intention to use condoms, (b) the couple forming their joint intention to use condoms, and (c) actual condom use behavior. We conducted a 2-wave longitudinal study of young heterosexual adult couples at high risk for HIV infection involving the collection of both individual- and couple-derived data. Results demonstrate the importance of both person (e.g., biological sex and dispositional dominance) and relational (e.g., relational power and amount of interest in the relationship, operationalized as commitment and perceived alternatives to the relationship) factors in predicting condom use intentions and behavior. Individuals who are lower in dispositional dominance are likely to incorporate their partner's intentions into their own individual intentions; the intentions of individuals who have less interest in the relationship are more highly predictive of the couple's joint intention; and the intentions of men and individuals higher in relationship power are more likely to exert a direct influence on condom use. These findings have implications for improving the health of high-risk individuals, including suggesting situations in which individuals are highly influenced by their partners' intentions. (PsycINFO Database Record (c) 2013 APA, all rights reserved).

Temperature-Dependent Function of the Glutamine Phosphoribosylpyrophosphate Amidotransferase Ammonia Channel and Coupling with Glycinamide Ribonucleotide Synthetase in a Hyperthermophile†

PubMed Central

Bera, Aloke Kumar; Chen, Sihong; Smith, Janet L.; Zalkin, Howard

2000-01-01

Genes encoding glutamine phosphoribosylpyrophosphate amidotransferase (GPAT) and glycinamide ribonucleotide synthetase (GARS) from Aquifex aeolicus were expressed in Escherichia coli, and the enzymes were purified to near homogeneity. Both enzymes were maximally active at a temperature of at least 90°C, with half-lives of 65 min for GPAT and 60 h for GARS at 80°C. GPAT activity is known to depend upon channeling of NH3 from a site in an N-terminal glutaminase domain to a distal phosphoribosylpyrophosphate site in a C-terminal domain where synthesis of phosphoribosylamine (PRA) takes place. The efficiency of channeling of NH3 for synthesis of PRA was found to increase from 34% at 37°C to a maximum of 84% at 80°C. The mechanism for transfer of PRA to GARS is not established, but diffusion between enzymes as a free intermediate appears unlikely based on a calculated PRA half-life of approximately 0.6 s at 90°C. Evidence was obtained for coupling between GPAT and GARS for PRA transfer. The coupling was temperature dependent, exhibiting a transition between 37 and 50°C, and remained relatively constant up to 90°C. The calculated PRA chemical half-life, however, decreased by a factor of 20 over this temperature range. These results provide evidence that coupling involves direct PRA transfer through GPAT-GARS interaction rather than free diffusion. PMID:10850988

Temperature-dependent function of the glutamine phosphoribosylpyrophosphate amidotransferase ammonia channel and coupling with glycinamide ribonucleotide synthetase in a hyperthermophile.

PubMed

Bera, A K; Chen, S; Smith, J L; Zalkin, H

2000-07-01

Genes encoding glutamine phosphoribosylpyrophosphate amidotransferase (GPAT) and glycinamide ribonucleotide synthetase (GARS) from Aquifex aeolicus were expressed in Escherichia coli, and the enzymes were purified to near homogeneity. Both enzymes were maximally active at a temperature of at least 90 degrees C, with half-lives of 65 min for GPAT and 60 h for GARS at 80 degrees C. GPAT activity is known to depend upon channeling of NH(3) from a site in an N-terminal glutaminase domain to a distal phosphoribosylpyrophosphate site in a C-terminal domain where synthesis of phosphoribosylamine (PRA) takes place. The efficiency of channeling of NH(3) for synthesis of PRA was found to increase from 34% at 37 degrees C to a maximum of 84% at 80 degrees C. The mechanism for transfer of PRA to GARS is not established, but diffusion between enzymes as a free intermediate appears unlikely based on a calculated PRA half-life of approximately 0.6 s at 90 degrees C. Evidence was obtained for coupling between GPAT and GARS for PRA transfer. The coupling was temperature dependent, exhibiting a transition between 37 and 50 degrees C, and remained relatively constant up to 90 degrees C. The calculated PRA chemical half-life, however, decreased by a factor of 20 over this temperature range. These results provide evidence that coupling involves direct PRA transfer through GPAT-GARS interaction rather than free diffusion.

Direct-Photon Spectra and Anisotropic Flow in Heavy Ion Collisions from Holography

NASA Astrophysics Data System (ADS)

Iatrakis, Ioannis; Kiritsis, Elias; Shen, Chun; Yang, Di-Lun

2017-03-01

The thermal-photon emission from strongly coupled gauge theories at finite temperature is calculated by using holographic models for QCD in the Veneziano limit (V-QCD). These emission rates are then embedded in hydrodynamic simulations combined with prompt photons from hard scattering and the thermal photons from hadron gas to analyze the spectra and anisotropic flow of direct photons at RHIC and LHC. The results from different sources responsible for the thermal photons in the quark gluon plasma (QGP) including the weakly coupled QGP (wQGP) from perturbative calculations, strongly coupled N = 4 super Yang-Mills (SYM) plasma (as a benchmark for reference), and Gubser's phenomenological model mimicking the strongly coupled QGP (sQGP) are then compared. It is found that the direct-photon spectra are enhanced in the strongly coupled scenario compared with the ones in the wQGP, especially at intermediate and high momenta, which improve the agreements with data. Moreover, by using IP-glassma initial states, both the elliptic flow and triangular flow of direct photons are amplified at high momenta (pT > 2.5 GeV) for V-QCD, while they are suppressed at low momenta compared to wQGP. The distinct results in holography stem from the blue-shift of emission rates in strong coupling. In addition, the spectra and flow in small collision systems were evaluated for future comparisons. It is found that thermal photons from the deconfined phase are substantial to reconcile the spectra and flow at high momenta.

Novel ultra-short and ultra-broadband polarization beam splitter based on a bent directional coupler.

PubMed

Dai, Daoxin; Bowers, John E

2011-09-12

A novel ultra-short polarization beam splitter (PBS) based on a bent directional coupler is proposed by utilizing the evanescent coupling between two bent optical waveguides with different core widths. For the bent directional coupler, there is a significant phase-mismatch for TE polarization while the phase-matching condition is satisfied for TM polarization. Therefore, the TM polarized light can be coupled from the narrow input waveguide to the adjacent wide waveguide while the TE polarization goes through the coupling region without significant coupling. An ultra-short (<10 μm-long) PBS is designed based on silicon-on-insulator nanowires and the length of the bent coupling region is as small as 4.5 μm while the gap width is chosen as 200 nm (large enough to simplify the fabrication). Numerical simulations show that the present PBS has a good fabrication tolerance for the variation of the waveguide width (more than ± 60 nm) and a very broad band (~200 nm) for an extinction ratio of >10 dB.

Comparison of advanced thermal and electrical storage for parabolic dish solar thermal power systems

NASA Astrophysics Data System (ADS)

Fujita, T.; Birur, G. C.; Schredder, J. M.; Bowyer, J. M.; Awaya, H. I.

Parabolic dish solar concentrator cluster concepts are explored, with attention given to thermal storage systems coupled to Stirling and Brayton cycle power conversion devices. Sensible heat storage involving molten salt (NaOH), liquid sodium, and solid cordierite bricks are considered for 1500 F thermal storage systems. Latent heat storage with NaF-MgF2 phase change materials are explored in terms of passive, active, and direct contact designs. Comparisons are made of the effectiveness of thermal storage relative to redox, Na-S, Zn-Cl, and Zn-Br battery storage systems. Molten lead trickling down through a phase change eutectic, the NaF-MgF2, formed the direct contact system. Heat transport in all systems is effected through Inconel pipes. Using a cost goal of 120-150 mills/kWh as the controlling parameter, sensible heat systems with molten salts transport with either Stirling or Brayton engines, or latent heat systems with Stirling engines, and latent heat-Brayton engine with direct contact were favored in the analyses. Battery storage systems, however, offered the most flexibility of applications.

Comparison of advanced thermal and electrical storage for parabolic dish solar thermal power systems

NASA Technical Reports Server (NTRS)

Fujita, T.; Birur, G. C.; Schredder, J. M.; Bowyer, J. M.; Awaya, H. I.

1982-01-01

Parabolic dish solar concentrator cluster concepts are explored, with attention given to thermal storage systems coupled to Stirling and Brayton cycle power conversion devices. Sensible heat storage involving molten salt (NaOH), liquid sodium, and solid cordierite bricks are considered for 1500 F thermal storage systems. Latent heat storage with NaF-MgF2 phase change materials are explored in terms of passive, active, and direct contact designs. Comparisons are made of the effectiveness of thermal storage relative to redox, Na-S, Zn-Cl, and Zn-Br battery storage systems. Molten lead trickling down through a phase change eutectic, the NaF-MgF2, formed the direct contact system. Heat transport in all systems is effected through Inconel pipes. Using a cost goal of 120-150 mills/kWh as the controlling parameter, sensible heat systems with molten salts transport with either Stirling or Brayton engines, or latent heat systems with Stirling engines, and latent heat-Brayton engine with direct contact were favored in the analyses. Battery storage systems, however, offered the most flexibility of applications.

Quantifying interactions between real oscillators with information theory and phase models: Application to cardiorespiratory coupling

NASA Astrophysics Data System (ADS)

Zhu, Yenan; Hsieh, Yee-Hsee; Dhingra, Rishi R.; Dick, Thomas E.; Jacono, Frank J.; Galán, Roberto F.

2013-02-01

Interactions between oscillators can be investigated with standard tools of time series analysis. However, these methods are insensitive to the directionality of the coupling, i.e., the asymmetry of the interactions. An elegant alternative was proposed by Rosenblum and collaborators [M. G. Rosenblum, L. Cimponeriu, A. Bezerianos, A. Patzak, and R. Mrowka, Phys. Rev. EPLEEE81063-651X10.1103/PhysRevE.65.041909 65, 041909 (2002); M. G. Rosenblum and A. S. Pikovsky, Phys. Rev. EPLEEE81063-651X10.1103/PhysRevE.64.045202 64, 045202 (2001)] which consists in fitting the empirical phases to a generic model of two weakly coupled phase oscillators. This allows one to obtain the interaction functions defining the coupling and its directionality. A limitation of this approach is that a solution always exists in the least-squares sense, even in the absence of coupling. To preclude spurious results, we propose a three-step protocol: (1) Determine if a statistical dependency exists in the data by evaluating the mutual information of the phases; (2) if so, compute the interaction functions of the oscillators; and (3) validate the empirical oscillator model by comparing the joint probability of the phases obtained from simulating the model with that of the empirical phases. We apply this protocol to a model of two coupled Stuart-Landau oscillators and show that it reliably detects genuine coupling. We also apply this protocol to investigate cardiorespiratory coupling in anesthetized rats. We observe reciprocal coupling between respiration and heartbeat and that the influence of respiration on the heartbeat is generally much stronger than vice versa. In addition, we find that the vagus nerve mediates coupling in both directions.

Directly Characterizing the Relative Strength and Momentum Dependence of Electron-Phonon Coupling Using Resonant Inelastic X-Ray Scattering

DOE Office of Scientific and Technical Information (OSTI.GOV)

Devereaux, T. P.; Shvaika, A. M.; Wu, K.

The coupling between lattice and charge degrees of freedom in condensed matter materials is ubiquitous and can often result in interesting properties and ordered phases, including conventional superconductivity, charge-density wave order, and metal-insulator transitions. Angle-resolved photoemission spectroscopy and both neutron and nonresonant x-ray scattering serve as effective probes for determining the behavior of appropriate, individual degrees of freedom—the electronic structure and lattice excitation, or phonon dispersion, respectively. However, each provides less direct information about the mutual coupling between the degrees of freedom, usually through self-energy effects, which tend to renormalize and broaden spectral features precisely where the coupling is strong,more » impacting one’s ability to quantitatively characterize the coupling. Here, we demonstrate that resonant inelastic x-ray scattering, or RIXS, can be an effective tool to directly determine the relative strength and momentum dependence of the electron-phonon coupling in condensed matter systems. Using a diagrammatic approach for an eight-band model of copper oxides, we study the contributions from the lowest-order diagrams to the full RIXS intensity for a realistic scattering geometry, accounting for matrix element effects in the scattering cross section, as well as the momentum dependence of the electron-phonon coupling vertex. A detailed examination of these maps offers a unique perspective into the characteristics of electron-phonon coupling, which complements both neutron and nonresonant x-ray scattering, as well as Raman and infrared conductivity.« less

Directly Characterizing the Relative Strength and Momentum Dependence of Electron-Phonon Coupling Using Resonant Inelastic X-Ray Scattering

DOE PAGES

Devereaux, T. P.; Shvaika, A. M.; Wu, K.; ...

2016-10-25

The coupling between lattice and charge degrees of freedom in condensed matter materials is ubiquitous and can often result in interesting properties and ordered phases, including conventional superconductivity, charge-density wave order, and metal-insulator transitions. Angle-resolved photoemission spectroscopy and both neutron and nonresonant x-ray scattering serve as effective probes for determining the behavior of appropriate, individual degrees of freedom—the electronic structure and lattice excitation, or phonon dispersion, respectively. However, each provides less direct information about the mutual coupling between the degrees of freedom, usually through self-energy effects, which tend to renormalize and broaden spectral features precisely where the coupling is strong,more » impacting one’s ability to quantitatively characterize the coupling. Here, we demonstrate that resonant inelastic x-ray scattering, or RIXS, can be an effective tool to directly determine the relative strength and momentum dependence of the electron-phonon coupling in condensed matter systems. Using a diagrammatic approach for an eight-band model of copper oxides, we study the contributions from the lowest-order diagrams to the full RIXS intensity for a realistic scattering geometry, accounting for matrix element effects in the scattering cross section, as well as the momentum dependence of the electron-phonon coupling vertex. A detailed examination of these maps offers a unique perspective into the characteristics of electron-phonon coupling, which complements both neutron and nonresonant x-ray scattering, as well as Raman and infrared conductivity.« less

The involvement of audio-motor coupling in the music-supported therapy applied to stroke patients.

PubMed

Rodriguez-Fornells, Antoni; Rojo, Nuria; Amengual, Julià L; Ripollés, Pablo; Altenmüller, Eckart; Münte, Thomas F

2012-04-01

Music-supported therapy (MST) has been developed recently to improve the use of the affected upper extremity after stroke. MST uses musical instruments, an electronic piano and an electronic drum set emitting piano sounds, to retrain fine and gross movements of the paretic upper extremity. In this paper, we first describe the rationale underlying MST, and we review the previous studies conducted on acute and chronic stroke patients using this new neurorehabilitation approach. Second, we address the neural mechanisms involved in the motor movement improvements observed in acute and chronic stroke patients. Third, we provide some recent studies on the involvement of auditory-motor coupling in the MST in chronic stroke patients using functional neuroimaging. Finally, these ideas are discussed and focused on understanding the dynamics involved in the neural circuit underlying audio-motor coupling and how functional connectivity could help to explain the neuroplastic changes observed after therapy in stroke patients. © 2012 New York Academy of Sciences.

Compact Vibration Damper

NASA Technical Reports Server (NTRS)

Ivanco, Thomas G. (Inventor)

2014-01-01

A vibration damper includes a rigid base with a mass coupled thereto for linear movement thereon. Springs coupled to the mass compress in response to the linear movement along either of two opposing directions. A converter coupled to the mass converts the linear movement to a corresponding rotational movement. A rotary damper coupled to the converter damps the rotational movement.

Recent research in snow hydrology

NASA Technical Reports Server (NTRS)

Dozier, Jeff

1987-01-01

Recent work on snow-pack energy exchange has involved detailed investigations on snow albedo and attempts to integrate energy-balance calculations over drainage basins. Along with a better understanding of the EM properties of snow, research in remote sensing has become more focused toward estimation of snow-pack properties. In snow metamorphism, analyses of the physical processes must now be coupled to better descriptions of the geometry of the snow microstructure. The dilution method now appears to be the best direct technique for measuring the liquid water content of snow; work on EM methods continues. Increasing attention to the chemistry of the snow pack has come with the general focus on acid precipitation in hydrology.

Directionality of coupling of physiological subsystems: age-related changes of cardiorespiratory interaction during different sleep stages in babies.

PubMed

Mrowka, Ralf; Cimponeriu, Laura; Patzak, Andreas; Rosenblum, Michael G

2003-12-01

Activity of many physiological subsystems has a well-expressed rhythmic character. Often, a dependency between physiological rhythms is established due to interaction between the corresponding subsystems. Traditional methods of data analysis allow one to quantify the strength of interaction but not the causal interrelation that is indispensable for understanding the mechanisms of interaction. Here we present a recently developed method for quantification of coupling direction and apply it to an important problem. Namely, we study the mutual influence of respiratory and cardiovascular rhythms in healthy newborns within the first 6 mo of life in quiet and active sleep. We find an age-related change of the coupling direction: the interaction is nearly symmetric during the first days and becomes practically unidirectional (from respiration to heart rhythm) at the age of 6 mo. Next, we show that the direction of interaction is mainly determined by respiratory frequency. If the latter is less than approximately 0.6 Hz, the interaction occurs dominantly from respiration to heart. With higher respiratory frequencies that only occur at very young ages, the dominating direction is less pronounced or even abolished. The observed dependencies are not related to sleep stage, suggesting that the coupling direction is determined by system-inherent dynamical processes, rather than by functional modulations. The directional analysis may be applied to other interacting narrow band oscillatory systems, e.g., in the central nervous system. Thus it is an important step forward in revealing and understanding causal mechanisms of interactions.

Evaluation of a Brief Marriage Intervention for Internal Behavioral Health Consultants in Primary Care

DTIC Science & Technology

2016-09-01

couples at risk for marital deterioration who would otherwise be unlikely to seek traditional couple counseling . The randomized trial is being...protocol to better assess (1) ability to involve couples who otherwise would not seek marriage counseling , and (2) whether participating in Marriage

Job-Sharing Couples in Academia: Career and Family Lifestyles.

ERIC Educational Resources Information Center

Mikitka, Kathleen F.; Koblinsky, Sally A.

1985-01-01

Investigates careers and family life-styles of 20 job-sharing couples in faculty positions at 12 colleges. Information was gathered about the couples' reasons for becoming involved in job sharing, conditions of their employment, their division of professional and household labor, their satisfaction with the job-sharing arrangement, and their…

Transfer entropy analysis of maternal and fetal heart rate coupling.

PubMed

Marzbanrad, Faezeh; Kimura, Yoshitaka; Endo, Miyuki; Palaniswami, Marimuthu; Khandoker, Ahsan H

2015-01-01

Although evidence of the short term relationship between maternal and fetal heart rates has been found in previous model-based studies, knowledge about the mechanism and patterns of the coupling during gestation is still limited. In this study, a model-free method based on Transfer Entropy (TE) was applied to quantify the maternal-fetal heart rate couplings in both directions. Furthermore, analysis of the lag at which TE was maximum and its changes throughout gestation, provided more information about the mechanism of coupling and its latency. Experimental results based on fetal electrocardiograms (fECGs) and maternal ECG showed the evidence of coupling for 62 out of 65 healthy mothers and fetuses in each direction, by statistically validating against the surrogate pairs. The fetuses were divided into three gestational age groups: early (16-25 weeks), mid (26-31 weeks) and late (32-41 weeks) gestation. The maximum TE from maternal to fetal heart rate significantly increased from early to mid gestation, while the coupling delay on both directions decreased significantly from mid to late gestation. These changes occur concomitant with the maturation of the fetal sensory and autonomic nervous systems with advancing gestational age. In conclusion, the application of TE with delays revealed detailed information about the changes in fetal-maternal heart rate coupling strength and latency throughout gestation, which could provide novel clinical markers of fetal development and well-being.

Swings and roundabouts: management of jealousy in heterosexual swinging couples.

PubMed

de Visser, Richard; McDonald, Dee

2007-06-01

Swinging involves consensual mutual involvement in extra-dyadic sex. Jealousy in swinging couples is an interesting topic for social psychological research, because it is a common and acceptable response to a romantic partner's real or imagined infidelity. This qualitative study examined the management of jealousy among four active heterosexual swinging couples living in southern England. Participants highlighted the importance of discussion and negotiation to develop a shared couple identity and shared rules and boundaries that allowed them to manage jealousy so that they could better enjoy swinging. Rather than seeking to eliminate jealousy, swingers may manage their feelings of jealousy in order to increase sexual excitement and arousal. This study adds to our understanding of jealousy among swingers and the broader issue of jealousy in intimate relationships.

Polarization-dependent coupling between a polarization-independent high-index-contrast subwavelength grating and waveguides

NASA Astrophysics Data System (ADS)

Katayama, Takeo; Ito, Jun; Kawaguchi, Hitoshi

2016-07-01

We investigated the optical coupling between a polarization-independent high-index-contrast subwavelength grating (HCG) and two orthogonal in-plane waveguides. We fabricated the HCG with waveguides on a silicon-on-insulator substrate and demonstrated that a waveguide with a strong output is switched by changing the polarization of light injected into the HCG. The light coupled more strongly to the waveguide in the direction perpendicular to the polarization of the incident light than to that in the parallel direction. If this waveguide-coupled HCG is incorporated into a polarization bistable vertical-cavity surface-emitting laser (VCSEL), the output waveguide can be switched by changing the lasing polarization of the VCSEL.

Palladium-catalyzed domino C,N-coupling/carbonylation/Suzuki coupling reaction: an efficient synthesis of 2-aroyl-/heteroaroylindoles.

PubMed

Arthuis, Martin; Pontikis, Renée; Florent, Jean-Claude

2009-10-15

A convenient one-pot synthesis of 2-aroylindoles using a domino palladium-catalyzed C,N-coupling/carbonylation/C,C-coupling sequence is described. The reaction involved easily prepared 2-gem-dibromovinylanilines and boronic acids under carbon monoxide. Optimized reaction conditions allowed the construction of a wide variety of highly functionalized 2-aroyl-/heteroaroylindoles in satisfactory yields.

Tet(L) and Tet(K) Tetracycline-Divalent Metal/H+ Antiporters: Characterization of Multiple Catalytic Modes and a Mutagenesis Approach to Differences in Their Efflux Substrate and Coupling Ion Preferences

PubMed Central

Jin, Jie; Guffanti, Arthur A.; Bechhofer, David H.; Krulwich, Terry A.

2002-01-01

The Tet(L) protein encoded in the Bacillus subtilis chromosome and the closely related Tet(K) protein from Staphylococcus aureus plasmids are multifunctional antiporters that have three cytoplasmic efflux substrates: a tetracycline-divalent metal (TC-Me2+) complex that bears a net single positive charge, Na+, and K+. Tet(L) and Tet(K) had been shown to couple efflux of each of these substrates to influx of H+ as the coupling ion. In this study, competitive cross-inhibition between K+ and other cytoplasmic efflux substrates was demonstrated. Tet(L) and Tet(K) had also been shown to use K+ as an alternate coupling ion in support of Na+ or K+ efflux. Here they were shown to couple TC-Me2+ efflux to K+ uptake as well, exhibiting greater use of K+ as a coupling ion as the external pH increased. The substrate and coupling ion preferences of the two Tet proteins differed, especially in the higher preference of Tet(K) than Tet(L) for K+, both as a cytoplasmic efflux substrate and as an external coupling ion. Site-directed mutagenesis was employed to test the hypothesis that some feature of the putative “antiporter motif,” motif C, of Tet proteins would be involved in these characteristic preferences. Mutation of the A157 in Tet(L) to a hydroxyamino acid resulted in a more Tet(K)-like K+ preference both as coupling ion and efflux substrate. A reciprocal S157A mutant of Tet(K) exhibited reduced K+ preference. Competitive inhibition among substrates and the parallel effects of the single mutation upon K+ preference, as both an efflux substrate and coupling ion, are compatible with a model in which a single translocation pathway through the Tet(L) and Tet(K) transporters is used both for the cytoplasmic efflux substrates and for the coupling ions, in an alternating fashion. However, the effects of the A157 and other mutations of Tet(L) indicate that even if there are a shared binding site and translocation pathway, some elements of that pathway are used by all substrates and others are important only for particular substrates. PMID:12169596

Wideband helicity dependent spoof surface plasmon polaritons coupling metasurface based on dispersion design.

PubMed

Dong, Guoxiang; Shi, Hongyu; He, Yuchen; Zhang, Anxue; Wei, Xiaoyong; Zhuang, Yongyong; Du, Bai; Xia, Song; Xu, Zhuo

2016-12-06

The surface plasmon polaritons (SPPs) have many potential application due to their local field enhancement and sub-wavelength characteristics. Recently, the gradient metasurface is introduced to couple the spoof SPPs in microwave frequency band. One of the most important issue which should be solved is the narrowband of spoof SPPs coupling on the gradient metasurface. Here, the metasurface is proposed to achieve the wideband helicity dependent directional spoof SPPs coupling for circular polarized light. Our research show that the coupling frequency of spoof SPPs on the gradient metasurface is determined by the dispersion of the metasurface, so the coupling frequency can be controlled by dispersion design. The careful design of each cell geometric parameters has provided many appropriate dispersion relations possessed by just one metasurface. The wave vector matching between the propagating wave and the spoof SPPs has been achieved at several frequencies for certain wave vector provided by the metasurface, which leads to wideband spoof SPPs coupling. This work has shown that wideband helicity dependent directional spoof SPPs coupling has been achieved with a high efficiency. Hence, the proposed wideband spoof SPPs coupling presents the improvement in practice applications.

Wideband helicity dependent spoof surface plasmon polaritons coupling metasurface based on dispersion design

PubMed Central

Dong, Guoxiang; Shi, Hongyu; He, Yuchen; Zhang, Anxue; Wei, Xiaoyong; Zhuang, Yongyong; Du, Bai; Xia, Song; Xu, Zhuo

2016-01-01

The surface plasmon polaritons (SPPs) have many potential application due to their local field enhancement and sub-wavelength characteristics. Recently, the gradient metasurface is introduced to couple the spoof SPPs in microwave frequency band. One of the most important issue which should be solved is the narrowband of spoof SPPs coupling on the gradient metasurface. Here, the metasurface is proposed to achieve the wideband helicity dependent directional spoof SPPs coupling for circular polarized light. Our research show that the coupling frequency of spoof SPPs on the gradient metasurface is determined by the dispersion of the metasurface, so the coupling frequency can be controlled by dispersion design. The careful design of each cell geometric parameters has provided many appropriate dispersion relations possessed by just one metasurface. The wave vector matching between the propagating wave and the spoof SPPs has been achieved at several frequencies for certain wave vector provided by the metasurface, which leads to wideband spoof SPPs coupling. This work has shown that wideband helicity dependent directional spoof SPPs coupling has been achieved with a high efficiency. Hence, the proposed wideband spoof SPPs coupling presents the improvement in practice applications. PMID:27922132

Determining triple gauge boson couplings from Higgs data.

PubMed

Corbett, Tyler; Éboli, O J P; Gonzalez-Fraile, J; Gonzalez-Garcia, M C

2013-07-05

In the framework of effective Lagrangians with the SU(2)(L)×U(1)(Y) symmetry linearly realized, modifications of the couplings of the Higgs field to the electroweak gauge bosons are related to anomalous triple gauge couplings (TGCs). Here, we show that the analysis of the latest Higgs boson production data at the LHC and Tevatron give rise to strong bounds on TGCs that are complementary to those from direct TGC analysis. We present the constraints on TGCs obtained by combining all available data on direct TGC studies and on Higgs production analysis.

Acoustically Induced Vibration of Structures: Reverberant Vs. Direct Acoustic Testing

NASA Technical Reports Server (NTRS)

Kolaini, Ali R.; O'Connell, Michael R.; Tsoi, Wan B.

2009-01-01

Large reverberant chambers have been used for several decades in the aerospace industry to test larger structures such as solar arrays and reflectors to qualify and to detect faults in the design and fabrication of spacecraft and satellites. In the past decade some companies have begun using direct near field acoustic testing, employing speakers, for qualifying larger structures. A limited test data set obtained from recent acoustic tests of the same hardware exposed to both direct and reverberant acoustic field testing has indicated some differences in the resulting structural responses. In reverberant acoustic testing, higher vibration responses were observed at lower frequencies when compared with the direct acoustic testing. In the case of direct near field acoustic testing higher vibration responses appeared to occur at higher frequencies as well. In reverberant chamber testing and direct acoustic testing, standing acoustic modes of the reverberant chamber or the speakers and spacecraft parallel surfaces can strongly couple with the fundamental structural modes of the test hardware. In this paper data from recent acoustic testing of flight hardware, that yielded evidence of acoustic standing wave coupling with structural responses, are discussed in some detail. Convincing evidence of the acoustic standing wave/structural coupling phenomenon will be discussed, citing observations from acoustic testing of a simple aluminum plate. The implications of such acoustic coupling to testing of sensitive flight hardware will be discussed. The results discussed in this paper reveal issues with over or under testing of flight hardware that could pose unanticipated structural and flight qualification issues. Therefore, it is of paramount importance to understand the structural modal coupling with standing acoustic waves that has been observed in both methods of acoustic testing. This study will assist the community to choose an appropriate testing method and test setup in the planning stages.

Extending Sexual Objectification Theory and Research to Minority Populations, Couples, and Men

ERIC Educational Resources Information Center

Heimerdinger-Edwards, Sarah R.; Vogel, David L.; Hammer, Joseph H.

2011-01-01

This reaction highlights several strengths of this major contribution and discusses some future directions in this line of research. The authors offer research ideas in the areas of cultural and cross-cultural issues, couples and relationships, as well as direct and indirect effects of sexual objectification on men. In terms of providing…

Ultrafast Directional Beam Switching in Coupled VCSELs

NASA Technical Reports Server (NTRS)

Ning, Cun-Zheng; Goorjian, Peter

2001-01-01

We propose a new approach to performing ultrafast directional beam switching using two coupled Vertical-Cavity Surface-Emitting Lasers (VCSELs). The proposed strategy is demonstrated for two VCSELs of 5.6 microns in diameter placed about 1 micron apart from the edges, showing a switching speed of 42 GHz with a maximum far-field angle span of about 10 degrees.

THE DEVELOPMENT OF IODINE BASED IMPINGER SOLUTIONS FOR THE EFFICIENT CAPTURE OF HG USING DIRECT INJECTION NEBULIZATION - INDUCTIVELY COUPLED PLASMA MASS SPECTROMETRY ANALYSIS

EPA Science Inventory

Inductively coupled plasma mass spectrometry (ICP/MS) with direct injection nebulization (DIN) was used to evaluate novel impinger solution compositions capable of capturing elemental mercury (Hgo) in EPA Method 5 type sampling. An iodine based impinger solutoin proved to be ver...

Transformer coupling for transmitting direct current through a barrier

DOEpatents

Brown, Ralph L.; Guilford, Richard P.; Stichman, John H.

1988-01-01

The transmission system for transmitting direct current from an energy source on one side of an electrical and mechanical barrier to a load on the other side of the barrier utilizes a transformer comprising a primary core on one side of the transformer and a secondary core on the other side of the transformer. The cores are magnetically coupled selectively by moving a magnetic ferrite coupler in and out of alignment with the poles of the cores. The direct current from the energy source is converted to a time varying current by an oscillating circuit, which oscillating circuit is optically coupled to a secondary winding on the secondary core to interrupt oscillations upon the voltage in the secondary winding exceeding a preselected level.

Transformer coupling for transmitting direct current through a barrier

DOEpatents

Brown, R.L.; Guilford, R.P.; Stichman, J.H.

1987-06-29

The transmission system for transmitting direct current from an energy source on one side of an electrical and mechanical barrier to a load on the other side of the barrier utilizes a transformer comprising a primary core on one side of the transformer and a secondary core on the other side of the transformer. The cores are magnetically coupled selectively by moving a magnetic ferrite coupler in and out of alignment with the poles of the cores. The direct current from the energy source is converted to a time varying current by an oscillating circuit, which oscillating circuit is optically coupled to a secondary winding on the secondary core to interrupt oscillations upon the voltage in the secondary winding exceeding a preselected level. 4 figs.

FLARE (Facility for Laboratory Reconnection Experiments): A Major Next-Step for Laboratory Studies of Magnetic Reconnection

NASA Astrophysics Data System (ADS)

Ji, H.; Bhattacharjee, A.; Prager, S.; Daughton, W. S.; Bale, S. D.; Carter, T. A.; Crocker, N.; Drake, J. F.; Egedal, J.; Sarff, J.; Wallace, J.; Belova, E.; Ellis, R.; Fox, W. R., II; Heitzenroeder, P.; Kalish, M.; Jara-Almonte, J.; Myers, C. E.; Que, W.; Ren, Y.; Titus, P.; Yamada, M.; Yoo, J.

2014-12-01

A new intermediate-scale plasma experiment, called the Facility for Laboratory Reconnection Experiments or FLARE, is under construction at Princeton as a joint project by five universities and two national labs to study magnetic reconnection in regimes directly relevant to space, solar and astrophysical plasmas. The currently existing small-scale experiments have been focusing on the single X-line reconnection process in plasmas either with small effective sizes or at low Lundquist numbers, both of which are typically very large in natural plasmas. These new regimes involve multiple X-lines as guided by a reconnection "phase diagram", in which different coupling mechanisms from the global system scale to the local dissipation scale are classified into different reconnection phases [H. Ji & W. Daughton, Phys. Plasmas 18, 111207 (2011)]. The design of the FLARE device is based on the existing Magnetic Reconnection Experiment (MRX) at Princeton (http://mrx.pppl.gov) and is to provide experimental access to the new phases involving multiple X-lines at large effective sizes and high Lundquist numbers, directly relevant to space and solar plasmas. The motivating major physics questions, the construction status, and the planned collaborative research especially with space and solar research communities will be discussed.

FLARE (Facility for Laboratory Reconnection Experiments): A Major Next-Step for Laboratory Studies of Magnetic Reconnection

NASA Astrophysics Data System (ADS)

Ji, Hantao; Bhattacharjee, A.; Prager, S.; Daughton, W.; Bale, Stuart D.; Carter, T.; Crocker, N.; Drake, J.; Egedal, J.; Sarff, J.; Fox, W.; Jara-Almonte, J.; Myers, C.; Ren, Y.; Yamada, M.; Yoo, J.

2015-04-01

A new intermediate-scale plasma experiment, called the Facility for Laboratory Reconnection Experiments or FLARE (flare.pppl.gov), is under construction at Princeton as a joint project by five universities and two national labs to study magnetic reconnection in regimes directly relevant to heliophysical and astrophysical plasmas. The currently existing small-scale experiments have been focusing on the single X-line reconnection process in plasmas either with small effective sizes or at low Lundquist numbers, both of which are typically very large in natural plasmas. These new regimes involve multiple X-lines as guided by a reconnection "phase diagram", in which different coupling mechanisms from the global system scale to the local dissipation scale are classified into different reconnection phases [H. Ji & W. Daughton, Phys. Plasmas 18, 111207 (2011)]. The design of the FLARE device is based on the existing Magnetic Reconnection Experiment (MRX) (mrx.pppl.gov) and is to provide experimental access to the new phases involving multiple X-lines at large effective sizes and high Lundquist numbers, directly relevant to magnetospheric, solar wind, and solar coronal plasmas. After a brief summary of recent laboratory results on the topic of magnetic reconnection, the motivating major physics questions, the construction status, and the planned collaborative research especially with heliophysics communities will be discussed.

Domain size and structure in exchange coupled [Co/Pt]/NiO/[Co/Pt] multilayers.

PubMed

Baruth, A; Adenwalla, S

2011-09-21

We investigate the competing effects of interlayer exchange coupling and magnetostatic coupling in the magnetic heterostructure ([Co/Pt]/NiO/[Co/Pt]) with perpendicular magnetic anisotropy (PMA). This particular heterostructure is unique among coupled materials with PMA in directly exhibiting both ferromagnetic and antiferromagnetic coupling, oscillating between the two as a function of spacer layer thickness. By systematically tuning the coupling interactions via a wedge-shaped NiO spacer layer, we explore the energetics that dictate magnetic domain formation using high resolution magnetic force microscopy coupled with the magneto-optical Kerr effect. This technique probes the microscopic and macroscopic magnetic behavior as a continuous function of thickness and the interlayer exchange coupling, including the regions where interlayer coupling goes through zero. We see significant changes in domain structure based on the sign of coupling, and also show that magnetic domain size is directly related to the magnitude of the interlayer exchange coupling energy, which generally dominates over the magnetostatic interactions. When magnetostatic interactions become comparable to the interlayer exchange coupling, a delicate interplay between the differing energy contributions is apparent and energy scales are extracted. The results are of intense interest to the magnetic recording industry and also illustrate a relatively new avenue of undiscovered physics, primarily dealing with the delicate balance of energies in the formation of magnetic domains for coupled systems with PMA, defining limits on domain size as well as the interplay between roughness, domains and magnetic coupling.

Elastic, inelastic, and 1-nucleon transfer channels in the 7Li+120Sn system

NASA Astrophysics Data System (ADS)

Kundu, A.; Santra, S.; Pal, A.; Chattopadhyay, D.; Tripathi, R.; Roy, B. J.; Nag, T. N.; Nayak, B. K.; Saxena, A.; Kailas, S.

2017-03-01

Background: Simultaneous description of major outgoing channels for a nuclear reaction by coupled-channels calculations using the same set of potential and coupling parameters is one of the difficult tasks to accomplish in nuclear reaction studies. Purpose: To measure the elastic, inelastic, and transfer cross sections for as many channels as possible in 7Li+120Sn system at different beam energies and simultaneously describe them by a single set of model calculations using fresco. Methods: Projectile-like fragments were detected using six sets of Si-detector telescopes to measure the cross sections for elastic, inelastic, and 1-nucleon transfer channels at two beam energies of 28 and 30 MeV. Optical model analysis of elastic data and coupled-reaction-channels (CRC) calculations that include around 30 reaction channels coupled directly to the entrance channel, with respective structural parameters, were performed to understand the measured cross sections. Results: Structure information available in the literature for some of the identified states did not reproduce the present data. Cross sections obtained from CRC calculations using a modified but single set of potential and coupling parameters were able to describe simultaneously the measured data for all the channels at both the measured energies as well as the existing data for elastic and inelastic cross sections at 44 MeV. Conclusions: Non-reproduction of some of the cross sections using the structure information available in the literature which are extracted from reactions involving different projectiles indicates that such measurements are probe dependent. New structural parameters were assigned for such states as well as for several new transfer states whose spectroscopic factors were not known.

Gating transitions in the selectivity filter region of a sodium channel are coupled to the domain IV voltage sensor.

PubMed

Capes, Deborah L; Arcisio-Miranda, Manoel; Jarecki, Brian W; French, Robert J; Chanda, Baron

2012-02-14

Voltage-dependent ion channels are crucial for generation and propagation of electrical activity in biological systems. The primary mechanism for voltage transduction in these proteins involves the movement of a voltage-sensing domain (D), which opens a gate located on the cytoplasmic side. A distinct conformational change in the selectivity filter near the extracellular side has been implicated in slow inactivation gating, which is important for spike frequency adaptation in neural circuits. However, it remains an open question whether gating transitions in the selectivity filter region are also actuated by voltage sensors. Here, we examine conformational coupling between each of the four voltage sensors and the outer pore of a eukaryotic voltage-dependent sodium channel. The voltage sensors of these sodium channels are not structurally symmetric and exhibit functional specialization. To track the conformational rearrangements of individual voltage-sensing domains, we recorded domain-specific gating pore currents. Our data show that, of the four voltage sensors, only the domain IV voltage sensor is coupled to the conformation of the selectivity filter region of the sodium channel. Trapping the outer pore in a particular conformation with a high-affinity toxin or disulphide crossbridge impedes the return of this voltage sensor to its resting conformation. Our findings directly establish that, in addition to the canonical electromechanical coupling between voltage sensor and inner pore gates of a sodium channel, gating transitions in the selectivity filter region are also coupled to the movement of a voltage sensor. Furthermore, our results also imply that the voltage sensor of domain IV is unique in this linkage and in the ability to initiate slow inactivation in sodium channels.

Evolution of cardiorespiratory interactions with age

PubMed Central

Iatsenko, D.; Bernjak, A.; Stankovski, T.; Shiogai, Y.; Owen-Lynch, P. J.; Clarkson, P. B. M.; McClintock, P. V. E.; Stefanovska, A.

2013-01-01

We describe an analysis of cardiac and respiratory time series recorded from 189 subjects of both genders aged 16–90. By application of the synchrosqueezed wavelet transform, we extract the respiratory and cardiac frequencies and phases with better time resolution than is possible with the marked events procedure. By treating the heart and respiration as coupled oscillators, we then apply a method based on Bayesian inference to find the underlying coupling parameters and their time dependence, deriving from them measures such as synchronization, coupling directionality and the relative contributions of different mechanisms. We report a detailed analysis of the reconstructed cardiorespiratory coupling function, its time evolution and age dependence. We show that the direct and indirect respiratory modulations of the heart rate both decrease with age, and that the cardiorespiratory coupling becomes less stable and more time-variable. PMID:23858485

Evolution of cardiorespiratory interactions with age.

PubMed

Iatsenko, D; Bernjak, A; Stankovski, T; Shiogai, Y; Owen-Lynch, P J; Clarkson, P B M; McClintock, P V E; Stefanovska, A

2013-08-28

We describe an analysis of cardiac and respiratory time series recorded from 189 subjects of both genders aged 16-90. By application of the synchrosqueezed wavelet transform, we extract the respiratory and cardiac frequencies and phases with better time resolution than is possible with the marked events procedure. By treating the heart and respiration as coupled oscillators, we then apply a method based on Bayesian inference to find the underlying coupling parameters and their time dependence, deriving from them measures such as synchronization, coupling directionality and the relative contributions of different mechanisms. We report a detailed analysis of the reconstructed cardiorespiratory coupling function, its time evolution and age dependence. We show that the direct and indirect respiratory modulations of the heart rate both decrease with age, and that the cardiorespiratory coupling becomes less stable and more time-variable.

Nonreciprocal Transverse Photonic Spin and Magnetization-Induced Electromagnetic Spin-Orbit Coupling

PubMed Central

Levy, Miguel; Karki, Dolendra

2017-01-01

We present a formulation of electromagnetic spin-orbit coupling in magneto-optic media, and propose an alternative source of spin-orbit coupling to non-paraxial optics vortices. Our treatment puts forth a formulation of nonreciprocal transverse-spin angular-momentum-density shifts for evanescent waves in magneto-optic waveguide media. It shows that magnetization-induced electromagnetic spin-orbit coupling is possible, and that it leads to unequal spin to orbital angular momentum conversion in magneto-optic media evanescent waves in opposite propagation-directions. Generation of free-space helicoidal beams based on this conversion is shown to be spin-helicity- and magnetization-dependent. We show that transverse-spin to orbital angular momentum coupling into magneto-optic waveguide media engenders spin-helicity-dependent unidirectional propagation. This unidirectional effect produces different orbital angular momenta in opposite directions upon excitation-spin-helicity reversals. PMID:28059120

Optimal estimation of the optomechanical coupling strength

NASA Astrophysics Data System (ADS)

Bernád, József Zsolt; Sanavio, Claudio; Xuereb, André

2018-06-01

We apply the formalism of quantum estimation theory to obtain information about the value of the nonlinear optomechanical coupling strength. In particular, we discuss the minimum mean-square error estimator and a quantum Cramér-Rao-type inequality for the estimation of the coupling strength. Our estimation strategy reveals some cases where quantum statistical inference is inconclusive and merely results in the reinforcement of prior expectations. We show that these situations also involve the highest expected information losses. We demonstrate that interaction times on the order of one time period of mechanical oscillations are the most suitable for our estimation scenario, and compare situations involving different photon and phonon excitations.

Abscisic Acid Acts as a Blocker of the Bitter Taste G Protein-Coupled Receptor T2R4.

PubMed

Pydi, Sai P; Jaggupilli, Appalaraju; Nelson, Ken M; Abrams, Suzanne R; Bhullar, Rajinder P; Loewen, Michele C; Chelikani, Prashen

2015-04-28

Bitter taste receptors (T2Rs) belong to the G protein-coupled receptor superfamily. In humans, 25 T2Rs mediate bitter taste sensation. In addition to the oral cavity, T2Rs are expressed in many extraoral tissues, including the central nervous system, respiratory system, and reproductive system. To understand the mechanistic roles of the T2Rs in oral and extraoral tissues, novel blockers or antagonists are urgently needed. Recently, we elucidated the binding pocket of T2R4 for its agonist quinine, and an antagonist and inhibitory neurotransmitter, γ-aminobutyric acid. This structure-function information about T2R4 led us to screen the plant hormone abscisic acid (ABA), its precursor (xanthoxin), and catabolite phaseic acid for their ability to bind and activate or inhibit T2R4. Molecular docking studies followed by functional assays involving calcium imaging confirmed that ABA is an antagonist with an IC50 value of 34.4 ± 1.1 μM. However, ABA precursor xanthoxin acts as an agonist on T2R4. Interestingly, molecular model-guided site-directed mutagenesis suggests that the T2R4 residues involved in quinine binding are also predominantly involved in binding to the novel antagonist, ABA. The antagonist ability of ABA was tested using another T2R4 agonist, yohimbine. Our results suggest that ABA does not inhibit yohimbine-induced T2R4 activity. The discovery of natural bitter blockers has immense nutraceutical and physiological significance and will help in dissecting the T2R molecular pathways in various tissues.

Potential sites for the perception of gravity in the acellular slime mold Physarum polycephalum.

PubMed

Block, I; Briegleb, W

1989-01-01

Recently a gravisensitivity of the acellular slime mold Physarum polycephalum, which possesses no specialized gravireceptor, could be established by conducting experiments under simulated and under real near weightlessness. In these experiments macroplasmodia showed a modulation of their contraction rhythm followed by regulation phenomena. Until now the perception mechanism for the gravistimulus is unknown, but several findings indicate the involvement of mitochondria: A) During the impediment of respiration the 0g-reaction is inhibited and the regulation is reduced. B) The response to a light stimulus and the following regulation phenomena strongly resemble the behavior during exposure to 0g, the only difference is that the two reactions are directed into opposite directions. In the blue-light reaction a flavin of the mitochondrial matrix seems to be involved in the light perception. C) The contraction rhythm as well as its modulations are coupled to rhythmic changes in the levels of ATP and calcium ions, involving the mitochondria as sites of energy production and of Ca(++)-storage. So the mitochondria could be the site of the regulation and they possibly are the receptor sites for the light and gravity stimuli. Also the observation of a morphologic polarity of the slime mold's plasmodial strands has to be considered: Cross-sections reveal that the ectoplasmic wall surrounding the streaming endoplasm is much thinner on the physically lower side than on the upper side of the strand--this applies to strands lying on or hanging on a horizontal surface. So, in addition to the mitochondria, also the morphologic polarity may be involved in the perception mechanism of the observed gravisensitivity and of the recently established geotaxis. The potential role of the nuclei and of the contractile elements in the perception of gravity is also discussed.

Multimode Directional Coupler

NASA Technical Reports Server (NTRS)

Simons, Rainee N. (Inventor); Wintucky, Edwin G. (Inventor)

2016-01-01

A multimode directional coupler is provided. In some embodiments, the multimode directional coupler is configured to receive a primary signal and a secondary signal at a first port of a primary waveguide. The primary signal is configured to propagate through the primary waveguide and be outputted at a second port of the primary waveguide. The multimode directional coupler also includes a secondary waveguide configured to couple the secondary signal from the primary waveguide with no coupling of the primary signal into the secondary waveguide. The secondary signal is configured to propagate through the secondary waveguide and be outputted from a port of the secondary waveguide.

Transition-metal-catalyzed direct arylation of (hetero)arenes by C-H bond cleavage.

PubMed

Ackermann, Lutz; Vicente, Rubén; Kapdi, Anant R

2009-01-01

The area of transition-metal-catalyzed direct arylation through cleavage of C-H bonds has undergone rapid development in recent years, and is becoming an increasingly viable alternative to traditional cross-coupling reactions with organometallic reagents. In particular, palladium and ruthenium catalysts have been described that enable the direct arylation of (hetero)arenes with challenging coupling partners--including electrophilic aryl chlorides and tosylates as well as simple arenes in cross-dehydrogenative arylations. Furthermore, less expensive copper, iron, and nickel complexes were recently shown to be effective for economically attractive direct arylations.

Lab-on-a-bubble: direct and indirect assays with portable Raman instrumentation

NASA Astrophysics Data System (ADS)

Carron, Keith; Schmit, Virginia; Scott, Brandon; Martoglio, Richard

2012-10-01

Lab-on-a-Bubble (LoB) is a new method for SERS (Surface Enhanced Raman Scattering) assays that combines separationand concentration of the assay results. A direct LoB assay is comprised of gold nanoparticles coupled directly to the ~30 μm diameter buoyant silica bubble. The direct LoB method was evaluated with cyanide and 5,5'-dithiobis(2-nitrobenzoic acid) (DTNB). An indirect assay uses the same ~ 30 μm diameter buoyant silica bubble and a silica coated SERS reporter. Both the bubble and SERS reporter are coated with a coupling agent for the analyte. The assay measures the amount of SERS reporter coupled to the bubble through a sandwich created by the analyte. The couling agent could consist of an immunological coupling agent (antibody) or a nucleic acid coupling agent (single strand DNA). The indirect LoB method was examined with Cholera toxin (CT) and antibodies against the β subunit. An LOD of ~ 170 pptrillion was measured for cyanide and a limit of detection of 1100 ng was found for CT. Instrumentation for the assay and a novel technique of dynamic SERS (DSERS) will also be discussed. The instrument is a small hand-held Raman device called the CBEx (Chemical Biological Explosive) with a novel raster system to detect heterogeneous or light sensitive materials. DSERS is a mathematical algorithm which eliminates background interference in SERS measurements with colloidal nanoparticles.

Nickel-Catalyzed Suzuki-Miyaura Cross-Coupling in a Green Alcohol Solvent for an Undergraduate Organic Chemistry Laboratory

ERIC Educational Resources Information Center

Hie, Liana; Chang, Jonah J.; Garg, Neil K.

2015-01-01

A modern undergraduate organic chemistry laboratory experiment involving the Suzuki-Miyaura coupling is reported. Although Suzuki-Miyaura couplings typically employ palladium catalysts in environmentally harmful solvents, this experiment features the use of inexpensive nickel catalysis, in addition to a "green" alcohol solvent. The…

An Evaluation of a Program to Help Dual-Earner Couples Share the Second Shift.

ERIC Educational Resources Information Center

Hawkins, Alan J.; And Others

1994-01-01

Used both traditional scientific and feminist methodologies to evaluate effectiveness of family life education program designed to help dual-earner couples (n=14 couples) share domestic labor. Both quantitative and qualitative data suggest that program produced small increases in husbands' involvement in both housework and child care and large…

Variable-Range Hopping through Marginally Localized Phonons

NASA Astrophysics Data System (ADS)

Banerjee, Sumilan; Altman, Ehud

2016-03-01

We investigate the effect of coupling Anderson localized particles in one dimension to a system of marginally localized phonons having a symmetry protected delocalized mode at zero frequency. This situation is naturally realized for electrons coupled to phonons in a disordered nanowire as well as for ultracold fermions coupled to phonons of a superfluid in a one-dimensional disordered trap. To determine if the coupled system can be many-body localized we analyze the phonon-mediated hopping transport for both the weak and strong coupling regimes. We show that the usual variable-range hopping mechanism involving a low-order phonon process is ineffective at low temperature due to discreteness of the bath at the required energy. Instead, the system thermalizes through a many-body process involving exchange of a diverging number n ∝-log T of phonons in the low temperature limit. This effect leads to a highly singular prefactor to Mott's well-known formula and strongly suppresses the variable range hopping rate. Finally, we comment on possible implications of this physics in higher dimensional electron-phonon coupled systems.

Integrated Coupling of Surface and Subsurface Flow with HYDRUS-2D

NASA Astrophysics Data System (ADS)

Hartmann, Anne; Šimůnek, Jirka; Wöhling, Thomas; Schütze, Niels

2016-04-01

Describing interactions between surface and subsurface flow processes is important to adequately define water flow in natural systems. Since overland flow generation is highly influenced by rainfall and infiltration, both highly spatially heterogeneous processes, overland flow is unsteady and varies spatially. The prediction of overland flow needs to include an appropriate description of the interactions between the surface and subsurface flow. Coupling surface and subsurface water flow is a challenging task. Different approaches have been developed during the last few years, each having its own advantages and disadvantages. A new approach by Weill et al. (2009) to couple overland flow and subsurface flow based on a generalized Richards equation was implemented into the well-known subsurface flow model HYDRUS-2D (Šimůnek et al., 2011). This approach utilizes the one-dimensional diffusion wave equation to model overland flow. The diffusion wave model is integrated in HYDRUS-2D by replacing the terms of the Richards equation in a pre-defined runoff layer by terms defining the diffusion wave equation. Using this approach, pressure and flux continuity along the interface between both flow domains is provided. This direct coupling approach provides a strong coupling of both systems based on the definition of a single global system matrix to numerically solve the coupled flow problem. The advantage of the direct coupling approach, compared to the loosely coupled approach, is supposed to be a higher robustness, when many convergence problems can be avoided (Takizawa et al., 2014). The HYDRUS-2D implementation was verified using a) different test cases, including a direct comparison with the results of Weill et al. (2009), b) an analytical solution of the kinematic wave equation, and c) the results of a benchmark test of Maxwell et al. (2014), that included several known coupled surface subsurface flow models. Additionally, a sensitivity analysis evaluating the effects of various model parameters on simulated overland flow (while considering or neglecting the effects of subsurface flow) was carried out to verify the applicability of the model to different problems. The model produced reasonable results in describing the diffusion wave approximation and its interactions with subsurface flow processes. The model could handle coupled surface-subsurface processes for conditions involving runoff generated by infiltration excess, saturation excess, or run-on, as well as a combination of these runoff generating processes. Several standard features of the HYDRUS 2D model, such as root water uptake and evaporation from the soil surface, as well as evaporation from runoff layer, can still be considered by the new model. The code required relatively small time steps when overland flow was active, resulting in long simulation times, and sometimes produced poor mass balance. The model nevertheless showed potential to be a useful tool for addressing various issues related to irrigation research and to natural generation of overland flow at the hillslope scale. Maxwell, R., Putti, M., Meyerhoff, S., Delf, J., Ferguson, I., Ivanov, V., Kim, J., Kolditz, O., Kollet, S., Kumar, M., Lopez, S., Niu, J., Paniconi, C., Park, Y.-J., Phanikumar, M., Shen, C., Sudicky, E., and Sulis, M. (2014). Surface-subsurface model intercomparison: A first set of benchmark results to diagnose integrated hydrology and feedbacks. Water Resourc. Res., 50:1531-1549. Šimůnek, J., van Genuchten, M. T., and Šejna, M. (2011). The HYDRUS Software Package for Simulating Two- and Three-Dimensional Movement of Water, Heat, and Multiple Solutes in Variably-Saturated Media. Technical Manual, Version 2.0, PC Progress, Prague, Czech Republic. Takizawa, K., Bazilevs Y., Tezduyar, T. E., Long, C.C., Marsden, A. L. and Schjodt.K., Patient-Specific Cardiovascular Fluid Mechanics Analysis with the ST and ALE-VMS Method in Idelsohn, S. R. (2014). Numerical Simulations of Coupled Problems in Engineering. Springer. Weill, S., Mouche, E., and Patin, J. (2009). A generalized Richards equation for surface/subsurface flow modelling. Journal of Hydrology, 366:9-20.

Target of rapamycin complex 2 signals to downstream effector yeast protein kinase 2 (Ypk2) through adheres-voraciously-to-target-of-rapamycin-2 protein 1 (Avo1) in Saccharomyces cerevisiae.

PubMed

Liao, Hsien-Ching; Chen, Mei-Yu

2012-02-24

The conserved Ser/Thr kinase target of rapamycin (TOR) serves as a central regulator in controlling cell growth-related functions. There exist two distinct TOR complexes, TORC1 and TORC2, each coupling to specific downstream effectors and signaling pathways. In Saccharomyces cerevisiae, TORC2 is involved in regulating actin organization and maintaining cell wall integrity. Ypk2 (yeast protein kinase 2), a member of the cAMP-dependent, cGMP-dependent, and PKC (AGC) kinase family, is a TORC2 substrate known to participate in actin and cell wall regulation. Employing avo3(ts) mutants with defects in TORC2 functions that are suppressible by active Ypk2, we investigated the molecular interactions involved in mediating TORC2 signaling to Ypk2. GST pulldown assays in yeast lysates demonstrated physical interactions between Ypk2 and components of TORC2. In vitro binding assays revealed that Avo1 directly binds to Ypk2. In avo3(ts) mutants, the TORC2-Ypk2 interaction was reduced and could be restored by AVO1 overexpression, highlighting the important role of Avo1 in coupling TORC2 to Ypk2. The interaction was mapped to an internal region (amino acids 600-840) of Avo1 and a C-terminal region of Ypk2. Ypk2(334-677), a truncated form of Ypk2 containing the Avo1-interacting region, was able to interfere with Avo1-Ypk2 interaction in vitro. Overexpressing Ypk2(334-677) in yeast cells resulted in a perturbation of TORC2 functions, causing defective cell wall integrity, aberrant actin organization, and diminished TORC2-dependent Ypk2 phosphorylation evidenced by the loss of an electrophoretic mobility shift. Together, our data support the conclusion that the direct Avo1-Ypk2 interaction is crucial for TORC2 signaling to the downstream Ypk2 pathway.

A Direct Mechanism of Ultrafast Intramolecular Singlet Fission in Pentacene Dimers

DOE PAGES

Fuemmeler, Eric G.; Sanders, Samuel N.; Pun, Andrew B.; ...

2016-05-05

Interest in materials that undergo singlet fission (SF) has been catalyzed by the potential to exceed the Shockley–Queisser limit of solar power conversion efficiency. In conventional materials, the mechanism of SF is an intermolecular process (xSF), which is mediated by charge transfer (CT) states and depends sensitively on crystal packing or molecular collisions. In contrast, recently reported covalently coupled pentacenes yield ~2 triplets per photon absorbed in individual molecules: the hallmark of intramolecular singlet fission (iSF). But, the mechanism of iSF is unclear. Here, using multireference electronic structure calculations and transient absorption spectroscopy, we establish that iSF can occur viamore » a direct coupling mechanism that is independent of CT states. Moreover, we show that a near-degeneracy in electronic state energies induced by vibronic coupling to intramolecular modes of the covalent dimer allows for strong mixing between the correlated triplet pair state and the local excitonic state, despite weak direct coupling.« less

The VENUS/NWChem software package. Tight coupling between chemical dynamics simulations and electronic structure theory

NASA Astrophysics Data System (ADS)

Lourderaj, Upakarasamy; Sun, Rui; Kohale, Swapnil C.; Barnes, George L.; de Jong, Wibe A.; Windus, Theresa L.; Hase, William L.

2014-03-01

The interface for VENUS and NWChem, and the resulting software package for direct dynamics simulations are described. The coupling of the two codes is considered to be a tight coupling since the two codes are compiled and linked together and act as one executable with data being passed between the two codes through routine calls. The advantages of this type of coupling are discussed. The interface has been designed to have as little interference as possible with the core codes of both VENUS and NWChem. VENUS is the code that propagates the direct dynamics trajectories and, therefore, is the program that drives the overall execution of VENUS/NWChem. VENUS has remained an essentially sequential code, which uses the highly parallel structure of NWChem. Subroutines of the interface that accomplish the data transmission and communication between the two computer programs are described. Recent examples of the use of VENUS/NWChem for direct dynamics simulations are summarized.

Directed assembly of nanoparticles to isolated diatom valves using the non-wetting characteristics after pyrolysis

NASA Astrophysics Data System (ADS)

Jantschke, A.; Fischer, C.; Hensel, R.; Braun, H.-G.; Brunner, E.

2014-09-01

A novel strategy for a directed nanoparticle coupling to isolated Stephanopyxis turris valves is presented. After pyrolysis, the valves exhibit incomplete wetting due to their characteristic T-shaped profiles as a prerequisite for a regioselective coupling reaction. A micromanipulation system allows for precise handling and their immobilization onto an adhesive substrate and manipulation into arrays.A novel strategy for a directed nanoparticle coupling to isolated Stephanopyxis turris valves is presented. After pyrolysis, the valves exhibit incomplete wetting due to their characteristic T-shaped profiles as a prerequisite for a regioselective coupling reaction. A micromanipulation system allows for precise handling and their immobilization onto an adhesive substrate and manipulation into arrays. Electronic supplementary information (ESI) available: BET surface area, TG/DTA measurements, HIM images and a video of an array of six valves of S. turris in a wetting experiment as well as a 3D animation based on CLSM measurements. See DOI: 10.1039/c4nr02662d

Evaluation of Computational Fluid Dynamics and Coupled Fluid-Solid Modeling for a Direct Transfer Preswirl System.

PubMed

Javiya, Umesh; Chew, John; Hills, Nick; Dullenkopf, Klaus; Scanlon, Timothy

2013-05-01

The prediction of the preswirl cooling air delivery and disk metal temperature are important for the cooling system performance and the rotor disk thermal stresses and life assessment. In this paper, standalone 3D steady and unsteady computation fluid dynamics (CFD), and coupled FE-CFD calculations are presented for prediction of these temperatures. CFD results are compared with previous measurements from a direct transfer preswirl test rig. The predicted cooling air temperatures agree well with the measurement, but the nozzle discharge coefficients are under predicted. Results from the coupled FE-CFD analyses are compared directly with thermocouple temperature measurements and with heat transfer coefficients on the rotor disk previously obtained from a rotor disk heat conduction solution. Considering the modeling limitations, the coupled approach predicted the solid metal temperatures well. Heat transfer coefficients on the rotor disk from CFD show some effect of the temperature variations on the heat transfer coefficients. Reasonable agreement is obtained with values deduced from the previous heat conduction solution.

Holographic photon production in heavy ion collisions

NASA Astrophysics Data System (ADS)

Iatrakis, Ioannis; Kiritsis, Elias; Shen, Chun; Yang, Di-Lun

2017-04-01

The thermal-photon emission from strongly coupled gauge theories at finite temperature is calculated using holographic models for QCD in the Veneziano limit (V-QCD). The emission rates are then embedded in hydrodynamic simulations combined with prompt photons from hard scattering and the thermal photons from hadron gas to analyze the spectra and anisotropic flow of direct photons at RHIC and LHC. The results from different sources responsible for the thermal photons in QGP including the weakly coupled QGP (wQGP) from perturbative calculations, strongly coupled N = 4 super Yang-Mills (SYM) plasma (as a benchmark for reference), and Gubser's phenomenological holographic model are then compared. It is found that the direct-photon spectra are enhanced in the strongly coupled scenario compared with the ones in the wQGP, especially at high momenta. Moreover, both the elliptic flow and triangular flow of direct photons are amplified at high momenta for V-QCD and the SYM plasma. The results are further compared with experimental observations.

Structural insight into the activation of a class B G-protein-coupled receptor by peptide hormones in live human cells

PubMed Central

Seidel, Lisa; Zarzycka, Barbara; Zaidi, Saheem A; Katritch, Vsevolod; Coin, Irene

2017-01-01

The activation mechanism of class B G-protein-coupled receptors (GPCRs) remains largely unknown. To characterize conformational changes induced by peptide hormones, we investigated interactions of the class B corticotropin-releasing factor receptor type 1 (CRF1R) with two peptide agonists and three peptide antagonists obtained by N-truncation of the agonists. Surface mapping with genetically encoded photo-crosslinkers and pair-wise crosslinking revealed distinct footprints of agonists and antagonists on the transmembrane domain (TMD) of CRF1R and identified numerous ligand-receptor contact sites, directly from the intact receptor in live human cells. The data enabled generating atomistic models of CRF- and CRF(12-41)-bound CRF1R, further explored by molecular dynamics simulations. We show that bound agonist and antagonist adopt different folds and stabilize distinct TMD conformations, which involves bending of helices VI and VII around flexible glycine hinges. Conservation of these glycine hinges among all class B GPCRs suggests their general role in activation of these receptors. DOI: http://dx.doi.org/10.7554/eLife.27711.001 PMID:28771403

3D Visible-Light Invisibility Cloak.

PubMed

Zheng, Bin; Zhu, Rongrong; Jing, Liqiao; Yang, Yihao; Shen, Lian; Wang, Huaping; Wang, Zuojia; Zhang, Xianmin; Liu, Xu; Li, Erping; Chen, Hongsheng

2018-06-01

The concept of an invisibility cloak is a fixture of science fiction, fantasy, and the collective imagination. However, a real device that can hide an object from sight in visible light from absolutely any viewpoint would be extremely challenging to build. The main obstacle to creating such a cloak is the coupling of the electromagnetic components of light, which would necessitate the use of complex materials with specific permittivity and permeability tensors. Previous cloaking solutions have involved circumventing this obstacle by functioning either in static (or quasistatic) fields where these electromagnetic components are uncoupled or in diffusive light scattering media where complex materials are not required. In this paper, concealing a large-scale spherical object from human sight from three orthogonal directions is reported. This result is achieved by developing a 3D homogeneous polyhedral transformation and a spatially invariant refractive index discretization that considerably reduce the coupling of the electromagnetic components of visible light. This approach allows for a major simplification in the design of 3D invisibility cloaks, which can now be created at a large scale using homogeneous and isotropic materials.

The SPS interference problem-electronic system effects and mitigation techniques

NASA Technical Reports Server (NTRS)

Juroshek, J. R.

1980-01-01

The potential for interference between solar power satellites (SPS) and other Earth satellite operations was examined along with interference problems involving specific electronic devices. Conclusions indicate that interference is likely in the 2500 MHz to 2690 MHz direct broadcast satellite band adjacent to SPS. Estimates of the adjacent channel noise from SPS in this band are as high as -124 dBc/4 kHz and -100 dBc/MHz, where dBc represents decibels relative to the total power in the fundamental. A second potential problem is the 7350 MHz, 3d harmonic from SPS that falls within the 7300 MHz to 7450 MHz space to Earth, government, satellite assignment. Catastrophic failures can be produced in integrated circuits when the microwave power levels coupled into inputs and power leads reach 1 to 100 watts. The failures are typically due to bonding wire melting, metallization failures, and junction shorting. Nondestructive interaction or interference, however, generally occurs with coupled power levels of the order of 10 milliwatts. This integration is due to the rectification of microwave energy by the numerous pn junctions within these circuits.

A Review of Hydrogen Production by Photosynthetic Organisms Using Whole-Cell and Cell-Free Systems.

PubMed

Martin, Baker A; Frymier, Paul D

2017-10-01

Molecular hydrogen is a promising currency in the future energy economy due to the uncertain availability of finite fossil fuel resources and environmental effects from their combustion. It also has important uses in the production of fertilizers and platform chemicals as well as in upgrading conventional fuels. Conventional methods for producing molecular hydrogen from natural gas produce carbon dioxide and use a finite resource as feedstock. However, these issues can be overcome by using light energy from the Sun combined with microorganisms and their molecular machinery capable of photosynthesis. In the presence of light, the proteins involved in photosynthesis coupled with appropriate catalysts in higher plants, algae, and cyanobacteria can produce molecular hydrogen, and optimization via genetic modifications and biomolecular engineering further improves production rates. In this review, we will discuss techniques that have been utilized to improve rates of hydrogen production in biological systems based on the protein machinery of photosynthesis coupled with appropriate catalysts. We will also suggest areas for improvement and future directions for work in the field.

Structure and functional interaction of the extracellular domain of human GABA[subscript B] receptor GBR2

DOE Office of Scientific and Technical Information (OSTI.GOV)

Geng, Yong; Xiong, Dazhi; Mosyak, Lidia

2012-10-24

Inhibitory neurotransmission is mediated primarily by GABA. The metabotropic GABA{sub B} receptor is a G protein-coupled receptor central to mammalian brain function. Malfunction of GABA{sub B} receptor has been implicated in several neurological disorders. GABA{sub B} receptor functions as a heterodimeric assembly of GBR1 and GBR2 subunits, where GBR1 is responsible for ligand-binding and GBR2 is responsible for G protein coupling. Here we demonstrate that the GBR2 ectodomain directly interacts with the GBR1 ectodomain to increase agonist affinity by selectively stabilizing the agonist-bound conformation of GBR1. We present the crystal structure of the GBR2 ectodomain, which reveals a polar heterodimericmore » interface. We also identify specific heterodimer contacts from both subunits, and GBR1 residues involved in ligand recognition. Lastly, our structural and functional data indicate that the GBR2 ectodomain adopts a constitutively open conformation, suggesting a structural asymmetry in the active state of GABA{sub B} receptor that is unique to the GABAergic system.« less

Ultra-slow mechanical stimulation of olfactory epithelium modulates consciousness by slowing cerebral rhythms in humans.

PubMed

Piarulli, A; Zaccaro, A; Laurino, M; Menicucci, D; De Vito, A; Bruschini, L; Berrettini, S; Bergamasco, M; Laureys, S; Gemignani, A

2018-04-26

The coupling between respiration and neural activity within olfactory areas and hippocampus has recently been unambiguously demonstrated, its neurophysiological basis sustained by the well-assessed mechanical sensitivity of the olfactory epithelium. We herein hypothesize that this coupling reverberates to the whole brain, possibly modulating the subject's behavior and state of consciousness. The olfactory epithelium of 12 healthy subjects was stimulated with periodical odorless air-delivery (frequency 0.05 Hz, 8 s on, 12 off). Cortical electrical activity (High Density-EEG) and perceived state of consciousness have been studied. The stimulation induced i) an enhancement of delta-theta EEG activity over the whole cortex mainly involving the Limbic System and Default Mode Network structures, ii) a reversal of the overall information flow directionality from wake-like postero-anterior to NREM sleep-like antero-posterior, iii) the perception of having experienced an Altered State of Consciousness. These findings could shed further light via a neurophenomenological approach on the links between respiration, cerebral activity and subjective experience, suggesting a plausible neurophysiological basis for interpreting altered states of consciousness induced by respiration-based meditative practices.

Rethinking the two-body problem: the segregation of women into geographically dispersed occupations.

PubMed

Benson, Alan

2014-10-01

Empirical research on the family cites the tendency for couples to relocate for husbands' careers as evidence against the gender neutrality of household economic decisions. For these studies, occupational segregation is a concern because occupations are not random by sex and mobility is not random by occupation. I find that the tendency for households to relocate for husbands' careers is better explained by the segregation of women into geographically dispersed occupations rather than by the direct prioritization of men's careers. Among never-married workers, women relocate for work less often than men, and the gender effect disappears after occupational segregation is accounted for. Although most two-earner families feature husbands in geographically clustered jobs involving frequent relocation for work, families are no less likely to relocate for work when it belongs to the wife. I conclude that future research in household mobility should treat occupational segregation occurring prior to marriage rather than gender bias within married couples as the primary explanation for the prioritization of husbands' careers in household mobility decisions.

Gas network model allows full reservoir coupling

DOE Office of Scientific and Technical Information (OSTI.GOV)

Methnani, M.M.

The gas-network flow model (Gasnet) developed for and added to an existing Qatar General Petroleum Corp. (OGPC) in-house reservoir simulator, allows improved modeling of the interaction among the reservoir, wells, and pipeline networks. Gasnet is a three-phase model that is modified to handle gas-condensate systems. The numerical solution is based on a control volume scheme that uses the concept of cells and junctions, whereby pressure and phase densities are defined in cells, while phase flows are defined at junction links. The model features common numerical equations for the reservoir, the well, and the pipeline components and an efficient state-variable solutionmore » method in which all primary variables including phase flows are solved directly. Both steady-state and transient flow events can be simulated with the same tool. Three test cases show how the model runs. One case simulates flow redistribution in a simple two-branch gas network. The second simulates a horizontal gas well in a waterflooded gas reservoir. The third involves an export gas pipeline coupled to a producing reservoir.« less

Two-Dimensional Electronic Spectroscopy of Benzene, Phenol, and Their Dimer: An Efficient First-Principles Simulation Protocol.

PubMed

Nenov, Artur; Mukamel, Shaul; Garavelli, Marco; Rivalta, Ivan

2015-08-11

First-principles simulations of two-dimensional electronic spectroscopy in the ultraviolet region (2DUV) require computationally demanding multiconfigurational approaches that can resolve doubly excited and charge transfer states, the spectroscopic fingerprints of coupled UV-active chromophores. Here, we propose an efficient approach to reduce the computational cost of accurate simulations of 2DUV spectra of benzene, phenol, and their dimer (i.e., the minimal models for studying electronic coupling of UV-chromophores in proteins). We first establish the multiconfigurational recipe with the highest accuracy by comparison with experimental data, providing reference gas-phase transition energies and dipole moments that can be used to construct exciton Hamiltonians involving high-lying excited states. We show that by reducing the active spaces and the number of configuration state functions within restricted active space schemes, the computational cost can be significantly decreased without loss of accuracy in predicting 2DUV spectra. The proposed recipe has been successfully tested on a realistic model proteic system in water. Accounting for line broadening due to thermal and solvent-induced fluctuations allows for direct comparison with experiments.

Remote carboxylation of halogenated aliphatic hydrocarbons with carbon dioxide

NASA Astrophysics Data System (ADS)

Juliá-Hernández, Francisco; Moragas, Toni; Cornella, Josep; Martin, Ruben

2017-05-01

Catalytic carbon-carbon bond formation has enabled the streamlining of synthetic routes when assembling complex molecules. It is particularly important when incorporating saturated hydrocarbons, which are common motifs in petrochemicals and biologically relevant molecules. However, cross-coupling methods that involve alkyl electrophiles result in catalytic bond formation only at specific and previously functionalized sites. Here we describe a catalytic method that is capable of promoting carboxylation reactions at remote and unfunctionalized aliphatic sites with carbon dioxide at atmospheric pressure. The reaction occurs via selective migration of the catalyst along the hydrocarbon side-chain with excellent regio- and chemoselectivity, representing a remarkable reactivity relay when compared with classical cross-coupling reactions. Our results demonstrate that site-selectivity can be switched and controlled, enabling the functionalization of less-reactive positions in the presence of a priori more reactive ones. Furthermore, we show that raw materials obtained in bulk from petroleum processing, such as alkanes and unrefined mixtures of olefins, can be used as substrates. This offers an opportunity to integrate a catalytic platform en route to valuable fatty acids by transforming petroleum-derived feedstocks directly.

Re-Thinking the Two-Body Problem: The Segregation of Women into Geographically-Dispersed Occupations

PubMed Central

Benson, Alan

2014-01-01

Empirical research on the family cites the tendency for couples to relocate for husbands’ careers as evidence against the gender-neutrality of household economic decisions. For these studies, occupational segregation is a concern because occupations are not random by sex and mobility is not random by occupation. I find the tendency for households to relocate for husbands’ careers is better-explained by the segregation of women into geographically-dispersed occupations rather than by the direct prioritization of men’s careers. Among never-married workers, women relocate for work less-often than men and the gender effect disappears after accounting for occupational segregation. While most two-earner families feature husbands in geographically-clustered jobs involving frequent relocation for work, families are no-less-likely to relocate for work when it belongs to the wife. I conclude future research in household mobility should treat occupational segregation occurring prior to marriage rather than gender bias within married couples as the primary explanation for the prioritization of husbands’ careers in household mobility decisions. PMID:25189156

Multiple-Year Application & Evaluation of Two-Way Coupled WRF-CMAQ with Aerosol Direct & Indirect Effects over the Continental U.S.

EPA Science Inventory

In this study, we present a multiple-year (2008-2010) application and evaluation of the two-way coupled WRFv3.4-CMAQv5.0.2 with both aerosol direct and indirect effects over the continental U.S. (CONUS) driven by chemical initial/boundary conditions derived from an advanced Earth...

Ultrafast Laser Beam Switching and Pulse Train Generation by Using Coupled Vertical-Cavity, Surface-Emitting Lasers (VCSELS)

NASA Technical Reports Server (NTRS)

Goorjian, Peter M. (Inventor); Ning, Cun-Zheng (Inventor)

2005-01-01

Ultrafast directional beam switching is achieved using coupled VCSELs. This approach is demonstrated to achieve beam switching frequencies of 40 GHz and more and switching directions of about eight degrees. This switching scheme is likely to be useful for ultrafast optical networks at frequencies much higher than achievable with other approaches.

Nonclassical properties of coherent light in a pair of coupled anharmonic oscillators

NASA Astrophysics Data System (ADS)

Alam, Nasir; Mandal, Swapan

2016-01-01

The Hamiltonian and hence the equations of motion involving the field operators of two anharmonic oscillators coupled through a linear one is framed. It is found that these equations of motion involving the non-commuting field operators are nonlinear and are coupled to each other and hence pose a great problem for getting the solutions. In order to investigate the dynamics and hence the nonclassical properties of the radiation fields, we obtain approximate analytical solutions of these coupled nonlinear differential equations involving the non-commuting field operators up to the second orders in anharmonic and coupling constants. These solutions are found useful for investigating the squeezing of pure and mixed modes, amplitude squared squeezing, principal squeezing, and the photon antibunching of the input coherent radiation field. With the suitable choice of the parameters (photon number in various field modes, anharmonic, and coupling constants, etc.), we calculate the second order variances of field quadratures of various modes and hence the squeezing, amplitude squared, and mixed mode squeezing of the input coherent light. In the absence of anharmonicities, it is found that these nonlinear nonclassical phenomena (squeezing of pure and mixed modes, amplitude squared squeezing and photon antibunching) are completely absent. The percentage of squeezing, mixed mode squeezing, amplitude squared squeezing increase with the increase of photon number and the dimensionless interaction time. The collapse and revival phenomena in squeezing, mixed mode squeezing and amplitude squared squeezing are exhibited. With the increase of the interaction time, the monotonic increasing nature of the squeezing effects reveal the presence of unwanted secular terms. It is established that the mere coupling of two oscillators through a third one does not produces the squeezing effects of input coherent light. However, the pure nonclassical phenomena of antibunching of photons in vacuum field modes are obtained through the mere coupling and hence the transfers of photons from the remaining coupled mode.

Nanoscale Plasmonic V-Groove Waveguides for the Interrogation of Single Fluorescent Bacterial Cells.

PubMed

Lotan, Oren; Bar-David, Jonathan; Smith, Cameron L C; Yagur-Kroll, Sharon; Belkin, Shimshon; Kristensen, Anders; Levy, Uriel

2017-09-13

We experimentally demonstrate the interrogation of an individual Escherichia coli cell using a nanoscale plasmonic V-groove waveguide. Several different configurations were studied. The first involved the excitation of the cell in a liquid environment because it flows on top of the waveguide nanocoupler, while the obtained fluorescence is coupled into the waveguide and collected at the other nanocoupler. The other two configurations involved the positioning of the bacterium within the nanoscale waveguide and its excitation in a dry environment either directly from the top or through waveguide modes. This is achieved by taking advantage of the waveguide properties not only for light guiding but also as a mechanical tool for trapping the bacteria within the V-grooves. The obtained results are supported by a set of numerical simulations, shedding more light on the mechanism of excitation. This demonstration paves the way for the construction of an efficient bioplasmonic chip for diverse cell-based sensing applications.

Salt bridge dynamics control substrate-induced conformational change in the membrane transporter GlpT

PubMed Central

Law, Christopher J.; Almqvist, Jonas; Bernstein, Adam; Goetz, Regina M.; Huang, Yafei; Soudant, Celine; Laaksonen, Aatto; Hovmöller, Sven; Wang, Da-Neng

2008-01-01

Summary Active transport of substrates across cytoplasmic membranes is of great physiological, medical and pharmaceutical importance. The glycerol-3-phosphate (G3P) transporter (GlpT) of the E. coli inner membrane is a secondary active antiporter from the ubiquitous major facilitator superfamily that couples the import of G3P to the efflux of inorganic phosphate (Pi) down its concentration gradient. Integrating information from a novel combination of structural, molecular dynamics simulations and biochemical studies, we identify the residues involved directly in binding of substrate to the inward-facing conformation of GlpT, thus defining the structural basis for the substrate-specificity of this transporter. The substrate binding mechanism involves protonation of a histidine residue at the binding site. Furthermore, our data suggest that the formation and breaking of inter- and intradomain salt bridges control the conformational change of the transporter that accompanies substrate translocation across the membrane. The mechanism we propose may be a paradigm for organophosphate/phosphate antiporters. PMID:18395745

Chlorodifluoromethane-triggered formation of difluoromethylated arenes catalysed by palladium

NASA Astrophysics Data System (ADS)

Feng, Zhang; Min, Qiao-Qiao; Fu, Xia-Ping; An, Lun; Zhang, Xingang

2017-09-01

Difluoromethylated aromatic compounds are of increasing importance in pharmaceuticals, agrochemicals and materials. Chlorodifluoromethane (ClCF2H), an inexpensive, abundant and widely used industrial raw material, represents the ideal and most straightforward difluoromethylating reagent, but introduction of the difluoromethyl group (CF2H) from ClCF2H into aromatics has not been reported. Here, we describe a direct palladium-catalysed difluoromethylation method for coupling ClCF2H with arylboronic acids and esters to generate difluoromethylated arenes with high efficiency. The reaction exhibits a remarkably broad substrate scope, including heteroarylboronic acids, and was used for difluoromethylation of a range of pharmaceuticals and biologically active compounds. Preliminary mechanistic studies revealed that a palladium difluorocarbene intermediate is involved in the reaction. Although numerous metal-difluorocarbene complexes have been prepared, the catalytic synthesis of difluoromethylated or difluoromethylenated compounds involving metal-difluorocarbene complexes has not received much attention. This new reaction therefore also opens the door to understand metal-difluorocarbene complex catalysed reactions.

Ultrafast Surface-Enhanced Raman Probing of the Role of Hot Electrons in Plasmon-Driven Chemistry.

PubMed

Brandt, Nathaniel C; Keller, Emily L; Frontiera, Renee R

2016-08-18

Hot electrons generated through plasmonic excitations in metal nanostructures show great promise for efficiently driving chemical reactions with light. However, the lifetime, yield, and mechanism of action of plasmon-generated hot electrons involved in a given photocatalytic process are not well understood. Here, we develop ultrafast surface-enhanced Raman scattering (SERS) as a direct probe of plasmon-molecule interactions in the plasmon-catalyzed dimerization of 4-nitrobenzenethiol to p,p'-dimercaptoazobenzene. Ultrafast SERS probing of these molecular reporters in plasmonic hot spots reveals transient Fano resonances, which we attribute to near-field coupling of Stokes-shifted photons to hot electron-driven metal photoluminescence. Surprisingly, we find that hot spots that yield more photoluminescence are much more likely to drive the reaction, which indirectly proves that plasmon-generated hot electrons induce the photochemistry. These ultrafast SERS results provide insight into the relative reactivity of different plasmonic hot spot environments and quantify the ultrafast lifetime of hot electrons involved in plasmon-driven chemistry.

High-Q/V Monolithic Diamond Microdisks Fabricated with Quasi-isotropic Etching.

PubMed

Khanaliloo, Behzad; Mitchell, Matthew; Hryciw, Aaron C; Barclay, Paul E

2015-08-12

Optical microcavities enhance light-matter interactions and are essential for many experiments in solid state quantum optics, optomechanics, and nonlinear optics. Single crystal diamond microcavities are particularly sought after for applications involving diamond quantum emitters, such as nitrogen vacancy centers, and for experiments that benefit from diamond's excellent optical and mechanical properties. Light-matter coupling rates in experiments involving microcavities typically scale with Q/V, where Q and V are the microcavity quality-factor and mode-volume, respectively. Here we demonstrate that microdisk whispering gallery mode cavities with high Q/V can be fabricated directly from bulk single crystal diamond. By using a quasi-isotropic oxygen plasma to etch along diamond crystal planes and undercut passivated diamond structures, we create monolithic diamond microdisks. Fiber taper based measurements show that these devices support TE- and TM-like optical modes with Q > 1.1 × 10(5) and V < 11(λ/n) (3) at a wavelength of 1.5 μm.

Global constraints on vector-like WIMP effective interactions

DOE PAGES

Blennow, Mattias; Coloma, Pilar; Fernandez-Martinez, Enrique; ...

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

PARTNER INVOLVEMENT: NEGOTIATING THE PRESENCE OF PARTNERS IN PSYCHOSOCIAL ASSESSMENT AS CONDUCTED BY MIDWIVES AND CHILD AND FAMILY HEALTH NURSES.

PubMed

Rollans, Mellanie; Kohlhoff, Jane; Meade, Tanya; Kemp, Lynn; Schmied, Virginia

2016-05-01

Universal screening for maternal depression and assessment of psychosocial risks has been integrated into the routine perinatal care provided in many Australian hospitals, but to date, partners/fathers have been largely excluded from the process. This study explored the ways in which clinicians in health service settings include partners who attend antenatal and postnatal visits with women. Qualitative data were collected using observations (n = 54), interviews (n = 60), and discussion groups (n = 7) with midwives and child and family health nurses who conducted the appointments. Transcripts from observations, interviews, and discussion groups underwent qualitative analysis, and key themes were identified. Results showed partners to have little or no involvement in psychosocial assessment and depression screening. Thematic analysis revealed four key themes: negotiating partner exclusion, partial inclusion, women's business or a couple concern? and they know anyway. Partner involvement appeared to be challenged particularly by mandatory interpersonal violence screening, which, according to health service policy, is to be conducted confidentially. Overall, results highlighted partner involvement in perinatal depression screening and psychosocial assessment processes and identified some of the benefits such as partner disclosure, but also the challenges and complexities of inclusion of partners. Clinical implications and directions for further education and research are discussed. © 2016 Michigan Association for Infant Mental Health.

Approximate analytical solutions of a pair of coupled anharmonic oscillators

NASA Astrophysics Data System (ADS)

Alam, Nasir; Mandal, Swapan; Öhberg, Patrik

2015-02-01

The Hamiltonian and the corresponding equations of motion involving the field operators of two quartic anharmonic oscillators indirectly coupled via a linear oscillator are constructed. The approximate analytical solutions of the coupled differential equations involving the non-commuting field operators are solved up to the second order in the anharmonic coupling. In the absence of nonlinearity these solutions are used to calculate the second order variances and hence the squeezing in pure and in mixed modes. The higher order quadrature squeezing and the amplitude squared squeezing of various field modes are also investigated where the squeezing in pure and in mixed modes are found to be suppressed. Moreover, the absence of a nonlinearity prohibits the higher order quadrature and higher ordered amplitude squeezing of the input coherent states. It is established that the mere coupling of two oscillators through a third one is unable to produce any squeezing effects of input coherent light, but the presence of a nonlinear interaction may provide squeezed states and other nonclassical phenomena.

New Parents’ Psychological Adjustment and Trajectories of Early Parental Involvement

PubMed Central

Jia, Rongfang; Kotila, Letitia E.; Schoppe-Sullivan, Sarah J.; Kamp Dush, Claire M.

2016-01-01

Trajectories of parental involvement time (engagement and child care) across 3, 6, and 9 months postpartum and associations with parents’ own and their partners’ psychological adjustment (dysphoria, anxiety, and empathic personal distress) were examined using a sample of dual-earner couples experiencing first-time parenthood (N = 182 couples). Using time diary measures that captured intensive parenting moments, hierarchical linear modeling analyses revealed that patterns of associations between psychological adjustment and parental involvement time depended on the parenting domain, aspect of psychological adjustment, and parent gender. Psychological adjustment difficulties tended to bias the 2-parent system toward a gendered pattern of “mother step in” and “father step out,” as father involvement tended to decrease, and mother involvement either remained unchanged or increased, in response to their own and their partners’ psychological adjustment difficulties. In contrast, few significant effects were found in models using parental involvement to predict psychological adjustment. PMID:27397935

Neuromagnetic Cerebellar Activity Entrains to the Kinematics of Executed Finger Movements.

PubMed

Marty, Brice; Wens, V; Bourguignon, M; Naeije, G; Goldman, S; Jousmäki, V; De Tiège, X

2018-05-03

This magnetoencephalography (MEG) study aims at characterizing the coupling between cerebellar activity and the kinematics of repetitive self-paced finger movements. Neuromagnetic signals were recorded in 11 right-handed healthy adults while they performed repetitive flexion-extensions of right-hand fingers at three different movement rates: slow (~ 1 Hz), medium (~ 2 Hz), and fast (~ 3 Hz). Right index finger acceleration was monitored with an accelerometer. Coherence analysis was used to index the coupling between right index finger acceleration and neuromagnetic signals. Dynamic imaging of coherent sources was used to locate coherent sources. Coupling directionality between primary sensorimotor (SM1), cerebellar, and accelerometer signals was assessed with renormalized partial directed coherence. Permutation-based statistics coupled with maximum statistic over the entire brain volume or restricted to the cerebellum were used. At all movement rates, maximum coherence peaked at SM1 cortex contralateral to finger movements at movement frequency (F0) and its first harmonic (F1). Significant (statistics restricted to the cerebellum) coherence consistently peaked at the right posterior lobe of the cerebellum at F0 with no influence of movement rate. Coupling between Acc and cerebellar signals was significantly stronger in the afferent than in the efferent direction with no effective contribution of cortico-cerebellar or cerebello-cortical pathways. This study demonstrates the existence of significant coupling between finger movement kinematics and neuromagnetic activity at the posterior cerebellar lobe ipsilateral to finger movement at F0. This coupling is mainly driven by spinocerebellar, presumably proprioceptive, afferences.

Short-chain fatty acids and ketones directly regulate sympathetic nervous system via G protein-coupled receptor 41 (GPR41).

PubMed

Kimura, Ikuo; Inoue, Daisuke; Maeda, Takeshi; Hara, Takafumi; Ichimura, Atsuhiko; Miyauchi, Satoshi; Kobayashi, Makio; Hirasawa, Akira; Tsujimoto, Gozoh

2011-05-10

The maintenance of energy homeostasis is essential for life, and its dysregulation leads to a variety of metabolic disorders. Under a fed condition, mammals use glucose as the main metabolic fuel, and short-chain fatty acids (SCFAs) produced by the colonic bacterial fermentation of dietary fiber also contribute a significant proportion of daily energy requirement. Under ketogenic conditions such as starvation and diabetes, ketone bodies produced in the liver from fatty acids are used as the main energy sources. To balance energy intake, dietary excess and starvation trigger an increase or a decrease in energy expenditure, respectively, by regulating the activity of the sympathetic nervous system (SNS). The regulation of metabolic homeostasis by glucose is well recognized; however, the roles of SCFAs and ketone bodies in maintaining energy balance remain unclear. Here, we show that SCFAs and ketone bodies directly regulate SNS activity via GPR41, a Gi/o protein-coupled receptor for SCFAs, at the level of the sympathetic ganglion. GPR41 was most abundantly expressed in sympathetic ganglia in mouse and humans. SCFA propionate promoted sympathetic outflow via GPR41. On the other hand, a ketone body, β-hydroxybutyrate, produced during starvation or diabetes, suppressed SNS activity by antagonizing GPR41. Pharmacological and siRNA experiments indicated that GPR41-mediated activation of sympathetic neurons involves Gβγ-PLCβ-MAPK signaling. Sympathetic regulation by SCFAs and ketone bodies correlated well with their respective effects on energy consumption. These findings establish that SCFAs and ketone bodies directly regulate GPR41-mediated SNS activity and thereby control body energy expenditure in maintaining metabolic homeostasis.

Direct Acylation of C(sp(3))-H Bonds Enabled by Nickel and Photoredox Catalysis.

PubMed

Joe, Candice L; Doyle, Abigail G

2016-03-14

Using nickel and photoredox catalysis, the direct functionalization of C(sp(3))-H bonds of N-aryl amines by acyl electrophiles is described. The method affords a diverse range of α-amino ketones at room temperature and is amenable to late-stage coupling of complex and biologically relevant groups. C(sp(3))-H activation occurs by photoredox-mediated oxidation to generate α-amino radicals which are intercepted by nickel in catalytic C(sp(3))-C coupling. The merger of these two modes of catalysis leverages nickel's unique properties in alkyl cross-coupling while avoiding limitations commonly associated with transition-metal-mediated C(sp(3))-H activation, including requirements for chelating directing groups and high reaction temperatures. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Collisionless coupling of a high- β expansion to an ambient, magnetized plasma. II. Experimental fields and measured momentum coupling

NASA Astrophysics Data System (ADS)

Bonde, Jeffrey; Vincena, Stephen; Gekelman, Walter

2018-04-01

The momentum coupled to a magnetized, ambient argon plasma from a high- β, laser-produced carbon plasma is examined in a collisionless, weakly coupled limit. The total electric field was measured by separately examining the induced component associated with the rapidly changing magnetic field of the high- β (kinetic β˜106), expanding plasma and the electrostatic component due to polarization of the expansion. Their temporal and spatial structures are discussed and their effect on the ambient argon plasma (thermal β˜10-2) is confirmed with a laser-induced fluorescence diagnostic, which directly probed the argon ion velocity distribution function. For the given experimental conditions, the electrostatic field is shown to dominate the interaction between the high- β expansion and the ambient plasma. Specifically, the expanding plasma couples energy and momentum into the ambient plasma by pulling ions inward against the flow direction.

Correlated Coulomb Drag in Capacitively Coupled Quantum-Dot Structures.

PubMed

Kaasbjerg, Kristen; Jauho, Antti-Pekka

2016-05-13

We study theoretically Coulomb drag in capacitively coupled quantum dots (CQDs)-a bias-driven dot coupled to an unbiased dot where transport is due to Coulomb mediated energy transfer drag. To this end, we introduce a master-equation approach that accounts for higher-order tunneling (cotunneling) processes as well as energy-dependent lead couplings, and identify a mesoscopic Coulomb drag mechanism driven by nonlocal multielectron cotunneling processes. Our theory establishes the conditions for a nonzero drag as well as the direction of the drag current in terms of microscopic system parameters. Interestingly, the direction of the drag current is not determined by the drive current, but by an interplay between the energy-dependent lead couplings. Studying the drag mechanism in a graphene-based CQD heterostructure, we show that the predictions of our theory are consistent with recent experiments on Coulomb drag in CQD systems.

The impact of SciDAC on US climate change research and the IPCCAR4

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wehner, Michael

2005-07-08

SciDAC has invested heavily in climate change research. We offer a candid opinion as to the impact of the DOE laboratories' SciDAC projects on the upcoming Fourth Assessment Report of the Intergovernmental Panel on Climate Change. As a result of the direct importance of climate change to society, climate change research is highly coordinated at the international level. The Intergovernmental Panel on Climate Change (IPCC) is charged with providing regular reports on the state of climate change research to government policymakers. These reports are the product of thousands of scientists efforts. A series of reviews involving both scientists and policymakersmore » make them among the most reviewed documents produced in any scientific field. The high profile of these reports acts a driver to many researchers in the climate sciences. The Fourth Assessment Report (AR4) is scheduled to be released in 2007. SciDAC sponsored research has enabled the United States climate modeling community to make significant contributions to this report. Two large multi-Laboratory SciDAC projects are directly relevant to the activities of the IPCC. The first, entitled ''Collaborative Design and Development of the Community Climate System Model for Terascale Computers'', has made important software contributions to the recently released third version of the Community Climate System Model (CCSM3.0) developed at the National Center for Atmospheric Research. This is a multi-institutional project involving Los Alamos National Laboratory, Oak Ridge National Laboratory, Lawrence Berkeley National Laboratory, Pacific Northwest National Laboratory, Argonne National Laboratory, Lawrence Livermore National Laboratory and the National Center for Atmospheric Research. The original principal investigators were Robert Malone and John B. Drake. The current principal investigators are Phil Jones and John B. Drake. The second project, entitled ''Earth System Grid II: Turning Climate Datasets into Community Resources'' aims to facilitate the distribution of the copious amounts of data produced by coupled climate model integrations to the general scientific community. This is also a multi-institutional project involving Argonne National Laboratory, Oak Ridge National Laboratory, Lawrence Berkeley National Laboratory, Lawrence Livermore National Laboratory and the National Center for Atmospheric Research. The principal investigators are Ian Foster, Don Middleton and Dean Williams. Perhaps most significant among the activities of the ''Collaborative Design'', project was the development of an efficient multi-processor coupling package. CCSM3.0 is an extraordinarily complicated physics code. The fully coupled model consists of separate submodels of the atmosphere, ocean, sea ice and land. In addition, comprehensive biogeochemistry and atmospheric chemistry submodels are under intensive current development. Each of these submodels is a large and sophisticated program in its own right. Furthermore, in the coupled model, each of the submodels, including the coupler, is a separate multiprocessor executable program. The coupler package must efficiently coordinate the communication as well as interpolate or aggregate information between these programs. This regridding function is necessary because each major subsystem (air, water or surface) is allowed to have its own independent grid.« less

77 FR 54848 - Airworthiness Directives; The Boeing Company Airplanes

Federal Register 2010, 2011, 2012, 2013, 2014

2012-09-06

... damage to the operation of other critical airplane systems due to electromagnetic coupling and large... strike to the tail strobe light, electromagnetic coupling and large transient voltages can be transmitted... electromagnetic coupling, since the tail strobe light is located in a flammable leakage zone, electrical current...

Doing the Scut Work of Infant Care: Does Religiousness Encourage Father Involvement?

PubMed

Demaris, Alfred; Mahoney, Annette; Pargament, Kenneth I

2011-04-01

Considerable debate exists regarding whether religiousness promotes or impedes greater father involvement in parenting. Our study addresses this issue using a Midwestern longitudinal dataset that tracks the transition to first parenthood for 169 married couples. We focus on performance of the "messier" tasks of infant care. We find little evidence that religiousness enhances father involvement in this domain. Biblically conservative couples exhibit a greater gender gap in childcare than others, with mothers more involved than fathers. The gender gap is also greater the more fathers work outside the home, the greater mothers' knowledge of infant development, and the more unadaptable the infant. Average daily childcare is lower the greater spouses' work hours, but higher with difficult pregnancies or fussy babies.

Doing the Scut Work of Infant Care: Does Religiousness Encourage Father Involvement?

PubMed Central

DeMaris, Alfred; Mahoney, Annette; Pargament, Kenneth I.

2011-01-01

Considerable debate exists regarding whether religiousness promotes or impedes greater father involvement in parenting. Our study addresses this issue using a Midwestern longitudinal dataset that tracks the transition to first parenthood for 169 married couples. We focus on performance of the “messier” tasks of infant care. We find little evidence that religiousness enhances father involvement in this domain. Biblically conservative couples exhibit a greater gender gap in childcare than others, with mothers more involved than fathers. The gender gap is also greater the more fathers work outside the home, the greater mothers’ knowledge of infant development, and the more unadaptable the infant. Average daily childcare is lower the greater spouses’ work hours, but higher with difficult pregnancies or fussy babies. PMID:21966024

Couple based family planning education: changes in male involvement and contraceptive use among married couples in Jimma Zone, Ethiopia.

PubMed

Tilahun, Tizta; Coene, Gily; Temmerman, Marleen; Degomme, Olivier

2015-07-21

Family planning contributes substantially in achieving the Millennium Development Goals. Recently, male involvement has gained considerable attention in family planning programs but the implementation thereof remains a challenge. In that context, our study aimed at measuring the effect of a six-month-long family planning education program on male involvement in family planning, as well as on couples' contraceptive practice. We conducted a quasi-experimental research among 811 married couples in Jimma Zone, southwest Ethiopia. Our study consisted of an intervention and a control group for comparative purpose; and surveyed before and after the implementation of the intervention. The intervention consisted of family planning education, given to both men and women at the household level in the intervention arm, in addition to monthly community gatherings. During the intervention period, households in the control group were not subject to particular activities but had access to routine health care services. We obtained follow-up data from 760 out of 786 (96.7%) couples who were originally enrolled in the survey. Findings were compared within and between groups before and after intervention surveys. At the baseline, contraceptive use in both control and intervention households were similar. After the intervention, we observed among men in the intervention arm a significantly higher level of willingness to be actively involved in family planning compared to the men in the control arm (p < 0.001). In addition, the difference between spouses that discussed family planning issues was less reported within the control group, both in the case of men and women ((p = 0.031) and (p < 0.001)) respectively. In general, a significant, positive difference in male involvement was observed. Concerning contraceptive use, there was change observed among the intervention group who were not using contraception at baseline. This study showed that family planning educational intervention, which includes both spouses and promotes spousal communication, might be useful to foster contraceptive practice among couples. The results also offer practical information on the benefits of male involvement in family planning as a best means to increase contraceptive use. Thus, providing opportunities to reinforce family planning education may strengthen the existing family planning service delivery system.

Postural Coordination during Socio-motor Improvisation

PubMed Central

Gueugnon, Mathieu; Salesse, Robin N.; Coste, Alexandre; Zhao, Zhong; Bardy, Benoît G.; Marin, Ludovic

2016-01-01

Human interaction often relies on socio-motor improvisation. Creating unprepared movements during social interaction is not a random process but relies on rules of synchronization. These situations do not only involve people to be coordinated, but also require the adjustment of their posture in order to maintain balance and support movements. The present study investigated posture in such a context. More precisely, we first evaluated the impact of amplitude and complexity of arm movements on posture in solo situation. Then, we assessed the impact of interpersonal coordination on posture using the mirror game in which dyads performed improvised and synchronized movements (i.e., duo situation). Posture was measured through ankle-hip coordination in medio-lateral and antero-posterior directions (ML and AP respectively). Our results revealed the spontaneous emergence of in-phase pattern in ML direction and antiphase pattern in AP direction for solo and duo situations. These two patterns respectively refer to the simultaneous flexion/extension of the ankles and the hips in the same or opposite direction. It suggests different functional roles of postural coordination patterns in each direction, with in-phase supporting task performance in ML (dynamical stability) and antiphase supporting postural control in AP (mechanical stability). Although amplitude of movement did not influence posture, movement complexity disturbed postural stability in both directions. Conversely, interpersonal coordination promoted postural stability in ML but not in AP direction. These results are discussed in terms of the difference in coupling strength between ankle-hip coordination and interpersonal coordination. PMID:27547193

Postural Coordination during Socio-motor Improvisation.

PubMed

Gueugnon, Mathieu; Salesse, Robin N; Coste, Alexandre; Zhao, Zhong; Bardy, Benoît G; Marin, Ludovic

2016-01-01

Human interaction often relies on socio-motor improvisation. Creating unprepared movements during social interaction is not a random process but relies on rules of synchronization. These situations do not only involve people to be coordinated, but also require the adjustment of their posture in order to maintain balance and support movements. The present study investigated posture in such a context. More precisely, we first evaluated the impact of amplitude and complexity of arm movements on posture in solo situation. Then, we assessed the impact of interpersonal coordination on posture using the mirror game in which dyads performed improvised and synchronized movements (i.e., duo situation). Posture was measured through ankle-hip coordination in medio-lateral and antero-posterior directions (ML and AP respectively). Our results revealed the spontaneous emergence of in-phase pattern in ML direction and antiphase pattern in AP direction for solo and duo situations. These two patterns respectively refer to the simultaneous flexion/extension of the ankles and the hips in the same or opposite direction. It suggests different functional roles of postural coordination patterns in each direction, with in-phase supporting task performance in ML (dynamical stability) and antiphase supporting postural control in AP (mechanical stability). Although amplitude of movement did not influence posture, movement complexity disturbed postural stability in both directions. Conversely, interpersonal coordination promoted postural stability in ML but not in AP direction. These results are discussed in terms of the difference in coupling strength between ankle-hip coordination and interpersonal coordination.

Scope and Mechanistic Investigations on the Solvent-Controlled Regio- and Stereoselective Formation of Enol Esters from the Ruthenium-Catalyzed Coupling Reaction of Terminal Alkynes and Carboxylic Acids

PubMed Central

Yi, Chae S.; Gao, Ruili

2009-01-01

The ruthenium-hydride complex (PCy3)2(CO)RuHCl was found to be a highly effective catalyst for the alkyne-to-carboxylic acid coupling reaction to give synthetically useful enol ester products. Strong solvent effect was observed for the ruthenium catalyst in modulating the activity and selectivity; the coupling reaction in CH2Cl2 led to the regioselective formation of gem-enol ester products, while the stereoselective formation of (Z)-enol esters was obtained in THF. The coupling reaction was found to be strongly inhibited by PCy3. The coupling reaction of both PhCO2H/PhC≡CD and PhCO2D/PhC≡CH led to the extensive deuterium incorporation on the vinyl positions of the enol ester products. An opposite Hammett value was observed when the correlation of a series of para-substituted p-X-C6H4CO2H (X = OMe, CH3, H, CF3, CN) with phenylacetylene was examined in CDCl3 (ρ = +0.30) and THF (ρ = −0.68). Catalytically relevant Ru-carboxylate and –vinylidene-carboxylate complexes, (PCy3)2(CO)(Cl)Ru(κ2-O2CC6H4-p-OMe) and (PCy3)2(CO)(Cl)RuC(=CHPh)O2CC6H4-p-OMe, were isolated, and the structure of both complexes was completely established by X-ray crystallography. A detailed mechanism of the coupling reaction involving a rate-limiting C-O bond formation step was proposed on the basis of these kinetic and structural studies. The regioselective formation of the gem-enol ester products in CH2Cl2 was rationalized by a direct migratory insertion of the terminal alkyne via a Ru-carboxylate species, whereas the stereoselective formation of (Z)-enol ester products in THF was explained by invoking a Ru-vinylidene species. PMID:20161379

Reversible mechanosensitive ion pumping as a part of mechanoelectrical transduction.

PubMed Central

Markin, V. S.; Tsong, T. Y.

1991-01-01

To explain the ability of some mechanosensitive cells to reverse the process of mechanotransduction and to generate mechanical oscillations and emit sound, a piezo-conformational coupling model (PCC model) is proposed. The model includes a transport protein which changes either its volume (PV-coupling) or its area in the membrane (gamma A-coupling) when undergoing conformational transitions. Such a protein can interact with an oscillating pressure to pump ions and create a transmembrane gradient if the affinities of the protein for ions are different at the two sides of membrane. The frequency and concentration windows for mechanical energy transduction were determined. Under optimal conditions, the efficiency of energy transduction can approach the theoretical maximum of 100%. If the concentration gradient exceeds the static head value (quasi-equilibrium which can be built up and maintained by this transport system), the energy transduction reverses and the transporter becomes a generator of mechanical oscillations at the expense of a concentration gradient. Estimation of thermodynamic parameters of the pump shows that the PV-coupling model would require large pressure oscillations to work while the gamma A-coupling model could work in physiological conditions. The gamma A-coupling mechanism may be used by cells for two purposes. In the reverse mode, it can be a force generator for various applications. In the direct mode, it may serve bioenergetic purposes by harvesting the energy of mechanical oscillations and storing it in the form of a concentration gradient. This pump has an unusual thermodynamic feature: it can distinguish the two components of the electrochemical potential gradient,i.e., the concentration gradient and the electrical potential, the latter serving as a permissive switch to open, or close, the pump when the potential reaches the threshold value.Predictions of the PCC model and its probable involvement in biological mechanotransduction are dicussed. PMID:1873468

Coupled Pendulums: A Physical System for Laboratory Investigations at Upper Secondary School

ERIC Educational Resources Information Center

Picciarelli, Vittorio; Stella, Rosa

2010-01-01

The topic of coupled oscillations is rich in physical content which is both interesting and complex. The study of the time evolution of coupled oscillator systems involves a mathematical formalization beyond the level of the upper secondary school student's competence. Here, we present an original approach, suitable even for secondary students, to…

Direct Visualization of Neurotransmitters in Rat Brain Slices by Desorption Electrospray Ionization Mass Spectrometry Imaging (DESI - MS)

NASA Astrophysics Data System (ADS)

Fernandes, Anna Maria A. P.; Vendramini, Pedro H.; Galaverna, Renan; Schwab, Nicolas V.; Alberici, Luciane C.; Augusti, Rodinei; Castilho, Roger F.; Eberlin, Marcos N.

2016-12-01

Mass spectrometry imaging (MSI) of neurotransmitters has so far been mainly performed by matrix-assisted laser desorption/ionization (MALDI) where derivatization reagents, deuterated matrix and/or high resolution, or tandem MS have been applied to circumvent problems with interfering ion peaks from matrix and from isobaric species. We herein describe the application of desorption electrospray ionization mass spectrometry imaging (DESI)-MSI in rat brain coronal and sagittal slices for direct spatial monitoring of neurotransmitters and choline with no need of derivatization reagents and/or deuterated materials. The amino acids γ-aminobutyric (GABA), glutamate, aspartate, serine, as well as acetylcholine, dopamine, and choline were successfully imaged using a commercial DESI source coupled to a hybrid quadrupole-Orbitrap mass spectrometer. The spatial distribution of the analyzed compounds in different brain regions was determined. We conclude that the ambient matrix-free DESI-MSI is suitable for neurotransmitter imaging and could be applied in studies that involve evaluation of imbalances in neurotransmitters levels.

Higher-order looping and nuclear organization of antigen receptor loci facilitate targeted RAG cleavage and regulated rearrangement in recombination centers

PubMed Central

Chaumeil, Julie; Micsinai, Mariann; Ntziachristos, Panagiotis; Deriano, Ludovic; Wang, Joy M-H; Ji, Yanhong; Nora, Elphege P.; Rodesch, Matthew J.; Jeddeloh, Jeffrey A.; Aifantis, Iannis; Kluger, Yuval; Schatz, David G.; Skok, Jane A.

2013-01-01

SUMMARY V(D)J recombination is essential for generating a diverse array of B and T cell receptors that can recognize and combat foreign antigen. As with any recombination event, tight control is essential to prevent the occurrence of genetic anomalies that drive cellular transformation. One important aspect of regulation is directed targeting of the RAG recombinase. Indeed, RAG accumulates at the 3’ end of individual antigen receptor loci poised for rearrangement, however, it is not known whether focal binding is involved in regulating cleavage, and what mechanisms lead to enrichment of RAG in this region. Here we show that mono-allelic looping out of the 3’ end of Tcra, coupled with transcription and increased chromatin/nuclear accessibility, are linked to focal RAG binding and ATM-mediated regulated mono-allelic cleavage on looped out 3’ regions. Our data identify higher order loop formation as a key determinant of directed RAG targeting and the maintenance of genome stability. PMID:23416051

Oxime-based linker libraries as a general approach for the rapid generation and screening of multidentate inhibitors

PubMed Central

Bahta, Medhanit; Liu, Fa; Kim, Sung-Eun; Stephen, Andrew G.; Fisher, Robert J.; Burke, Terrence R.

2013-01-01

The described oxime-based library protocol provides detailed procedures for the linkage of aminooxy functionality with aldehyde building blocks that result in the generation of libraries of multidentate inhibitors. Synthesis of inhibitors for protein tyrosine phosphatases (PTPs) and antagonists directed against the human tumor susceptibility gene 101 (Tsg101) are shown as examples. Three steps are involved: a) the design and synthesis of aminooxy platforms; b) tethering with aldehydes to form oxime-based linkages with sufficient purity; and c) direct in vitro biological evaluation of oxime products without purification. Each coupling reaction is a) performed in capped microtubes at room temperature; b) diluted for inhibitory evaluation and c) screened with targets in microplates to provide IC50 or Kd values. The synthesis of the aminooxy platforms takes 3–5 days; tethering with the aldehydes takes 24 h; and inhibition assay of enzymes and protein-protein interactions (PPIs) takes 30 min and 2 h respectively. PMID:22422315

Analysis of solid propellant combustion in a closed vessel including secondary reaction

NASA Technical Reports Server (NTRS)

Benreuven, M.; Summerfield, M.

1980-01-01

A theory for combustion of solid propellants in a closed vessel is presented allowing for residual exothermic chemical reaction in the bulk of the gas in the vessel. Particular attention is given to propellants exhibiting thick gaseous flame zones such as nitrocellulose, double-base and nitramine propellants. For these, the reaction at high pressures is assumed to involve mainly the oxidation of residual hydrocarbons by NO. It is shown that the direct dynamic coupling between the exothermicity, the molecular weight reduction and the changing pressure can influence the dp/dt-p traces obtained, in a manner not directly related to mass burning rate of the solid. Energy and species conservation equations are derived for the bulk of the vessel in differential form; the system is solved numerically. The results show the effect of extended chemical reaction upon measurable combustion characteristics such as dp/dt-p and burn rate pressure exponent, demonstrating its potential importance in interpretation of closed vessel firing data, depending on the pace of the residual gas phase reactions.

Grassmann phase space theory and the Jaynes-Cummings model

NASA Astrophysics Data System (ADS)

Dalton, B. J.; Garraway, B. M.; Jeffers, J.; Barnett, S. M.

2013-07-01

The Jaynes-Cummings model of a two-level atom in a single mode cavity is of fundamental importance both in quantum optics and in quantum physics generally, involving the interaction of two simple quantum systems—one fermionic system (the TLA), the other bosonic (the cavity mode). Depending on the initial conditions a variety of interesting effects occur, ranging from ongoing oscillations of the atomic population difference at the Rabi frequency when the atom is excited and the cavity is in an n-photon Fock state, to collapses and revivals of these oscillations starting with the atom unexcited and the cavity mode in a coherent state. The observation of revivals for Rydberg atoms in a high-Q microwave cavity is key experimental evidence for quantisation of the EM field. Theoretical treatments of the Jaynes-Cummings model based on expanding the state vector in terms of products of atomic and n-photon states and deriving coupled equations for the amplitudes are a well-known and simple method for determining the effects. In quantum optics however, the behaviour of the bosonic quantum EM field is often treated using phase space methods, where the bosonic mode annihilation and creation operators are represented by c-number phase space variables, with the density operator represented by a distribution function of these variables. Fokker-Planck equations for the distribution function are obtained, and either used directly to determine quantities of experimental interest or used to develop c-number Langevin equations for stochastic versions of the phase space variables from which experimental quantities are obtained as stochastic averages. Phase space methods have also been developed to include atomic systems, with the atomic spin operators being represented by c-number phase space variables, and distribution functions involving these variables and those for any bosonic modes being shown to satisfy Fokker-Planck equations from which c-number Langevin equations are often developed. However, atomic spin operators satisfy the standard angular momentum commutation rules rather than the commutation rules for bosonic annihilation and creation operators, and are in fact second order combinations of fermionic annihilation and creation operators. Though phase space methods in which the fermionic operators are represented directly by c-number phase space variables have not been successful, the anti-commutation rules for these operators suggest the possibility of using Grassmann variables—which have similar anti-commutation properties. However, in spite of the seminal work by Cahill and Glauber and a few applications, the use of phase space methods in quantum optics to treat fermionic systems by representing fermionic annihilation and creation operators directly by Grassmann phase space variables is rather rare. This paper shows that phase space methods using a positive P type distribution function involving both c-number variables (for the cavity mode) and Grassmann variables (for the TLA) can be used to treat the Jaynes-Cummings model. Although it is a Grassmann function, the distribution function is equivalent to six c-number functions of the two bosonic variables. Experimental quantities are given as bosonic phase space integrals involving the six functions. A Fokker-Planck equation involving both left and right Grassmann differentiations can be obtained for the distribution function, and is equivalent to six coupled equations for the six c-number functions. The approach used involves choosing the canonical form of the (non-unique) positive P distribution function, in which the correspondence rules for the bosonic operators are non-standard and hence the Fokker-Planck equation is also unusual. Initial conditions, such as those above for initially uncorrelated states, are discussed and used to determine the initial distribution function. Transformations to new bosonic variables rotating at the cavity frequency enable the six coupled equations for the new c-number functions-that are also equivalent to the canonical Grassmann distribution function-to be solved analytically, based on an ansatz from an earlier paper by Stenholm. It is then shown that the distribution function is exactly the same as that determined from the well-known solution based on coupled amplitude equations. In quantum-atom optics theories for many atom bosonic and fermionic systems are needed. With large atom numbers, treatments must often take into account many quantum modes—especially for fermions. Generalisations of phase space distribution functions of phase space variables for a few modes to phase space distribution functionals of field functions (which represent the field operators, c-number fields for bosons, Grassmann fields for fermions) are now being developed for large systems. For the fermionic case, the treatment of the simple two mode problem represented by the Jaynes-Cummings model is a useful test case for the future development of phase space Grassmann distribution functional methods for fermionic applications in quantum-atom optics.

Laser-direct-drive program: Promise, challenge, and path forward

DOE Office of Scientific and Technical Information (OSTI.GOV)

Campbell, E. M.; Goncharov, V. N.; Sangster, T. C.

Along with laser-indirect (x-ray)-drive and magnetic-drive target concepts, laser direct drive is a viable approach to achieving ignition and gain with inertial confinement fusion. In the United States, a national program has been established to demonstrate and understand the physics of laser direct drive. The program utilizes the Omega Laser Facility to conduct implosion and coupling physics at the nominally 30-kJ scale and laser–plasma interaction and coupling physics at the MJ scale at the National Ignition Facility. This paper will discuss the motivation and challenges for laser direct drive and the broad-based program presently underway in the United States.

Laser-direct-drive program: Promise, challenge, and path forward

DOE PAGES

Campbell, E. M.; Goncharov, V. N.; Sangster, T. C.; ...

2017-03-19

Along with laser-indirect (x-ray)-drive and magnetic-drive target concepts, laser direct drive is a viable approach to achieving ignition and gain with inertial confinement fusion. In the United States, a national program has been established to demonstrate and understand the physics of laser direct drive. The program utilizes the Omega Laser Facility to conduct implosion and coupling physics at the nominally 30-kJ scale and laser–plasma interaction and coupling physics at the MJ scale at the National Ignition Facility. This paper will discuss the motivation and challenges for laser direct drive and the broad-based program presently underway in the United States.

Hippocampal memory consolidation during sleep: a comparison of mammals and birds

PubMed Central

Rattenborg, Niels C.; Martinez-Gonzalez, Dolores; Roth, Timothy C.; Pravosudov, Vladimir V.

2010-01-01

The transition from wakefulness to sleep is marked by pronounced changes in brain activity. The brain rhythms that characterize the two main types of mammalian sleep, slow-wave sleep (SWS) and rapid eye movement (REM) sleep, are thought to be involved in the functions of sleep. In particular, recent theories suggest that the synchronous slow-oscillation of neocortical neuronal membrane potentials, the defining feature of SWS, is involved in processing information acquired during wakefulness. According to the Standard Model of memory consolidation, during wakefulness the hippocampus receives input from neocortical regions involved in the initial encoding of an experience and binds this information into a coherent memory trace that is then transferred to the neocortex during SWS where it is stored and integrated within preexisting memory traces. Evidence suggests that this process selectively involves direct connections from the hippocampus to the prefrontal cortex (PFC), a multimodal, high-order association region implicated in coordinating the storage and recall of remote memories in the neocortex. The slow-oscillation is thought to orchestrate the transfer of information from the hippocampus by temporally coupling hippocampal sharp-wave/ripples (SWRs) and thalamocortical spindles. SWRs are synchronous bursts of hippocampal activity, during which waking neuronal firing patterns are reactivated in the hippocampus and neocortex in a coordinated manner. Thalamocortical spindles are brief 7–14 Hz oscillations that may facilitate the encoding of information reactivated during SWRs. By temporally coupling the readout of information from the hippocampus with conditions conducive to encoding in the neocortex, the slow-oscillation is thought to mediate the transfer of information from the hippocampus to the neocortex. Although several lines of evidence are consistent with this function for mammalian SWS, it is unclear whether SWS serves a similar function in birds, the only taxonomic group other than mammals to exhibit SWS and REM sleep. Based on our review of research on avian sleep, neuroanatomy, and memory, although involved in some forms of memory consolidation, avian sleep does not appear to be involved in transferring hippocampal memories to other brain regions. Despite exhibiting the slow-oscillation, SWRs and spindles have not been found in birds. Moreover, although birds independently evolved a brain region – the caudolateral nidopallium (NCL) – involved in performing high-order cognitive functions similar to those performed by the PFC, direct connections between the NCL and hippocampus have not been found in birds, and evidence for the transfer of information from the hippocampus to the NCL or other extra-hippocampal regions is lacking. Although based on the absence of evidence for various traits, collectively, these findings suggest that unlike mammalian SWS, avian SWS may not be involved in transferring memories from the hippocampus. Furthermore, it suggests that the slow-oscillation, the defining feature of mammalian and avian SWS, may serve a more general function independent of that related to coordinating the transfer of information from the hippocampus to the PFC in mammals. Given that SWS is homeostatically regulated (a process intimately related to the slow-oscillation) in mammals and birds, functional hypotheses linked to this process may apply to both taxonomic groups. PMID:21070585

Hippocampal memory consolidation during sleep: a comparison of mammals and birds.

PubMed

Rattenborg, Niels C; Martinez-Gonzalez, Dolores; Roth, Timothy C; Pravosudov, Vladimir V

2011-08-01

The transition from wakefulness to sleep is marked by pronounced changes in brain activity. The brain rhythms that characterize the two main types of mammalian sleep, slow-wave sleep (SWS) and rapid eye movement (REM) sleep, are thought to be involved in the functions of sleep. In particular, recent theories suggest that the synchronous slow-oscillation of neocortical neuronal membrane potentials, the defining feature of SWS, is involved in processing information acquired during wakefulness. According to the Standard Model of memory consolidation, during wakefulness the hippocampus receives input from neocortical regions involved in the initial encoding of an experience and binds this information into a coherent memory trace that is then transferred to the neocortex during SWS where it is stored and integrated within preexisting memory traces. Evidence suggests that this process selectively involves direct connections from the hippocampus to the prefrontal cortex (PFC), a multimodal, high-order association region implicated in coordinating the storage and recall of remote memories in the neocortex. The slow-oscillation is thought to orchestrate the transfer of information from the hippocampus by temporally coupling hippocampal sharp-wave/ripples (SWRs) and thalamocortical spindles. SWRs are synchronous bursts of hippocampal activity, during which waking neuronal firing patterns are reactivated in the hippocampus and neocortex in a coordinated manner. Thalamocortical spindles are brief 7-14 Hz oscillations that may facilitate the encoding of information reactivated during SWRs. By temporally coupling the readout of information from the hippocampus with conditions conducive to encoding in the neocortex, the slow-oscillation is thought to mediate the transfer of information from the hippocampus to the neocortex. Although several lines of evidence are consistent with this function for mammalian SWS, it is unclear whether SWS serves a similar function in birds, the only taxonomic group other than mammals to exhibit SWS and REM sleep. Based on our review of research on avian sleep, neuroanatomy, and memory, although involved in some forms of memory consolidation, avian sleep does not appear to be involved in transferring hippocampal memories to other brain regions. Despite exhibiting the slow-oscillation, SWRs and spindles have not been found in birds. Moreover, although birds independently evolved a brain region--the caudolateral nidopallium (NCL)--involved in performing high-order cognitive functions similar to those performed by the PFC, direct connections between the NCL and hippocampus have not been found in birds, and evidence for the transfer of information from the hippocampus to the NCL or other extra-hippocampal regions is lacking. Although based on the absence of evidence for various traits, collectively, these findings suggest that unlike mammalian SWS, avian SWS may not be involved in transferring memories from the hippocampus. Furthermore, it suggests that the slow-oscillation, the defining feature of mammalian and avian SWS, may serve a more general function independent of that related to coordinating the transfer of information from the hippocampus to the PFC in mammals. Given that SWS is homeostatically regulated (a process intimately related to the slow-oscillation) in mammals and birds, functional hypotheses linked to this process may apply to both taxonomic groups. © 2010 The Authors. Biological Reviews © 2010 Cambridge Philosophical Society.

Electric power generating plant having direct-coupled steam and compressed-air cycles

DOEpatents

Drost, M.K.

1981-01-07

An electric power generating plant is provided with a Compressed Air Energy Storage (CAES) system which is directly coupled to the steam cycle of the generating plant. The CAES system is charged by the steam boiler during off peak hours, and drives a separate generator during peak load hours. The steam boiler load is thereby levelized throughout an operating day.

Electric power generating plant having direct coupled steam and compressed air cycles

DOEpatents

Drost, Monte K.

1982-01-01

An electric power generating plant is provided with a Compressed Air Energy Storage (CAES) system which is directly coupled to the steam cycle of the generating plant. The CAES system is charged by the steam boiler during off peak hours, and drives a separate generator during peak load hours. The steam boiler load is thereby levelized throughout an operating day.

Amygdala-prefrontal connectivity during appraisal of symptom-related stimuli in obsessive-compulsive disorder.

PubMed

Paul, Sandra; Beucke, Jan C; Kaufmann, Christian; Mersov, Anna; Heinzel, Stephan; Kathmann, Norbert; Simon, Daniela

2018-04-06

Cognitive models of obsessive-compulsive disorder (OCD) posit dysfunctional appraisal of disorder-relevant stimuli in patients, suggesting disturbances in the processes relying on amygdala-prefrontal connectivity. Recent neuroanatomical models add to the traditional view of dysfunction in corticostriatal circuits by proposing alterations in an affective circuit including amygdala-prefrontal connections. However, abnormalities in amygdala-prefrontal coupling during symptom provocation, and particularly during conditions that require stimulus appraisal, remain to be demonstrated directly. Amygdala-prefrontal connectivity was examined in unmedicated OCD patients during appraisal (v. distraction) of symptom-provoking stimuli compared with an emotional control condition. Subsequent analyses tested whether hypothesized connectivity alterations could be also identified during passive viewing and the resting state in two independent samples. During symptom provocation, reductions in positive coupling between amygdala and orbitofrontal cortex were observed in OCD patients relative to healthy control participants during appraisal and passive viewing of OCD-relevant stimuli, whereas abnormally high amygdala-ventromedial prefrontal cortex coupling was found when appraisal was distracted by a secondary task. In contrast, there were no group differences in amygdala connectivity at rest. Our finding of abnormal amygdala-prefrontal connectivity during appraisal of symptom-related (relative to generally aversive) stimuli is consistent with the involvement of affective circuits in the functional neuroanatomy of OCD. Aberrant connectivity can be assumed to impact stimulus appraisal and emotion regulation, but might also relate to fear extinction deficits, which have recently been described in OCD. Taken together, we propose to integrate abnormalities in amygdala-prefrontal coupling in affective models of OCD.

Development of the T+M coupled flow–geomechanical simulator to describe fracture propagation and coupled flow–thermal–geomechanical processes in tight/shale gas systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, Jihoon; Moridis, George J.

2013-10-01

We developed a hydraulic fracturing simulator by coupling a flow simulator to a geomechanics code, namely T+M simulator. Modeling of the vertical fracture development involves continuous updating of the boundary conditions and of the data connectivity, based on the finite element method for geomechanics. The T+M simulator can model the initial fracture development during the hydraulic fracturing operations, after which the domain description changes from single continuum to double or multiple continua in order to rigorously model both flow and geomechanics for fracture-rock matrix systems. The T+H simulator provides two-way coupling between fluid-heat flow and geomechanics, accounting for thermoporomechanics, treatsmore » nonlinear permeability and geomechanical moduli explicitly, and dynamically tracks changes in the fracture(s) and in the pore volume. We also fully accounts for leak-off in all directions during hydraulic fracturing. We first validate the T+M simulator, matching numerical solutions with the analytical solutions for poromechanical effects, static fractures, and fracture propagations. Then, from numerical simulation of various cases of the planar fracture propagation, shear failure can limit the vertical fracture propagation of tensile failure, because of leak-off into the reservoirs. Slow injection causes more leak-off, compared with fast injection, when the same amount of fluid is injected. Changes in initial total stress and contributions of shear effective stress to tensile failure can also affect formation of the fractured areas, and the geomechanical responses are still well-posed.« less

Transmutation of a heme protein.

PubMed Central

Barker, P D; Ferrer, J C; Mylrajan, M; Loehr, T M; Feng, R; Konishi, Y; Funk, W D; MacGillivray, R T; Mauk, A G

1993-01-01

Residue Asn57 of bovine liver cytochrome b5 has been replaced with a cysteine residue, and the resulting variant has been isolated from recombinant Escherichia coli as a mixture of four major species: A, BI, BII, and C. A combination of electronic spectroscopy, 1H NMR spectroscopy, resonance Raman spectroscopy, electrospray mass spectrometry, and direct electrochemistry has been used to characterize these four major cytochrome derivatives. The red form A (E(m) = -19 mV) is found to possess a heme group bound covalently through a thioether linkage involving Cys57 and the alpha carbon of the heme 4-vinyl group. Form BI has a covalently bound heme group coupled through a thioether linkage involving the beta carbon of the heme 4-vinyl group. Form BII is similar to BI except that the sulfur involved in the thioether linkage is oxidized to a sulfoxide. The green form C (E(m) = 175 mV) possesses a noncovalently bound prosthetic group with spectroscopic properties characteristic of a chlorin. A mechanism is proposed for the generation of these derivatives, and the implications of these observations for the biosynthesis of cytochrome c and naturally occurring chlorin prosthetic groups are discussed. PMID:8341666

Expression, stabilization and purification of membrane proteins via diverse protein synthesis systems and detergents involving cell-free associated with self-assembly peptide surfactants.

PubMed

Zheng, Xuan; Dong, Shuangshuang; Zheng, Jie; Li, Duanhua; Li, Feng; Luo, Zhongli

2014-01-01

G-protein coupled receptors (GPCRs) are involved in regulating most of physiological actions and metabolism in the bodies, which have become most frequently addressed therapeutic targets for various disorders and diseases. Purified GPCR-based drug discoveries have become routine that approaches to structural study, novel biophysical and biochemical function analyses. However, several bottlenecks that GPCR-directed drugs need to conquer the problems including overexpression, solubilization, and purification as well as stabilization. The breakthroughs are to obtain efficient protein yield and stabilize their functional conformation which are both urgently requiring of effective protein synthesis system methods and optimal surfactants. Cell-free protein synthesis system is superior to the high yields and post-translation modifications, and early signs of self-assembly peptide detergents also emerged to superiority in purification of membrane proteins. We herein focus several predominant protein synthesis systems and surfactants involving the novel peptide detergents, and uncover the advantages of cell-free protein synthesis system with self-assembling peptide detergents in purification of functional GPCRs. This review is useful to further study in membrane proteins as well as the new drug exploration. Copyright © 2014 Elsevier Inc. All rights reserved.

CAPILLARY ELECTROPHORESIS COUPLED ON-LINE WITH INDUCTIVELY COUPLED PLASMA MASS SPECTROMETRY FOR ELEMENTAL SPECIATION

EPA Science Inventory

A novel interface to connect a capillary electrophoresis (CE) system with an inductively coupled plasma mass spectrometric (ICPMS) detector is reported here. The interface was built using a direct injection nebulizer (DIN) system. In this interface, the CE capillary was placed co...

Wavelength-insensitive radiation coupling for multi-quantum well sensor based on intersubband absorption

NASA Technical Reports Server (NTRS)

Gunapala, Sarath D. (Inventor); Bandara, Sumith V. (Inventor); Liu, John K. (Inventor)

2006-01-01

Devices and techniques for coupling radiation to intraband quantum-well semiconductor sensors that are insensitive to the wavelength of the coupled radiation. At least one reflective surface is implemented in the quantum-well region to direct incident radiation towards the quantum-well layers.

Waveguide coupling in the few-cycle regime

NASA Astrophysics Data System (ADS)

Leblond, Hervé; Terniche, Said

2016-04-01

We consider the coupling of two optical waveguides in the few-cycle regime. The analysis is performed in the frame of a generalized Kadomtsev-Petviashvili model. A set of two coupled modified Korteweg-de Vries equations is derived, and it is shown that three types of coupling can occur, involving the linear index, the dispersion, or the nonlinearity. The linear nondispersive coupling is investigated numerically, showing the formation of vector solitons. Separate pulses may be trapped together if they have not initially the same location, size, or phase, and even if their initial frequencies differ.

Relationship satisfaction in lesbian couples: Review, methodological critique, and research agenda.

PubMed

Lavner, Justin A

2017-01-02

There has been increased interest in and attention to understanding the characteristics associated with relationship satisfaction among same-sex couples. This review examines the individual, couple, and external factors associated with relationship satisfaction among contemporary lesbian couples, highlighting domains such as internalized homophobia, personality, communication, conflict, sex, stress, and social support. I discuss methodological concerns and future directions to advance research in this area.

Synchronization between two coupled direct current glow discharge plasma sources

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chaubey, Neeraj; Mukherjee, S.; Sen, A.

2015-02-15

Experimental results on the nonlinear dynamics of two coupled glow discharge plasma sources are presented. A variety of nonlinear phenomena including frequency synchronization and frequency pulling are observed as the coupling strength is varied. Numerical solutions of a model representation of the experiment consisting of two coupled asymmetric Van der Pol type equations are found to be in good agreement with the observed results.

Artificial reproductive technologies (ART) applications in Turkey as viewed by feminists.

PubMed

Sahinoglu-Pelin, S

2002-01-01

Since 1979, a lot of couples have benefited, in terms of having babies, from Artificial Reproductive Technologies (ART). In Turkey, there are presently about 20 centres in existence for this purpose where two approved sets of regulations are in operation; the second being an improved form of the former. In this paper, ART applications in Turkey, as viewed by feminists, will be discussed. During ART, the body of the woman concerned is directly involved. And after every application, the possibility of not having a living baby can adversely affect the physical and psychological state of the woman in question with the trauma being sometimes beyond endurance. In the two sets of approved regulations mentioned above, this application has been questioned in terms of ethics.

Finite difference time domain calculation of transients in antennas with nonlinear loads

NASA Technical Reports Server (NTRS)

Luebbers, Raymond J.; Beggs, John H.; Kunz, Karl S.; Chamberlin, Kent

1991-01-01

In this paper transient fields for antennas with more general geometries are calculated directly using Finite Difference Time Domain methods. In each FDTD cell which contains a nonlinear load, a nonlinear equation is solved at each time step. As a test case the transient current in a long dipole antenna with a nonlinear load excited by a pulsed plane wave is computed using this approach. The results agree well with both calculated and measured results previously published. The approach given here extends the applicability of the FDTD method to problems involving scattering from targets including nonlinear loads and materials, and to coupling between antennas containing nonlinear loads. It may also be extended to propagation through nonlinear materials.

An improved dual-frequency technique for the remote sensing of ocean currents and wave spectra

NASA Technical Reports Server (NTRS)

Schuler, D. L.; Eng, W. P.

1984-01-01

A two frequency microwave radar technique for the remote sensing of directional ocean wave spectra and surface currents is investigated. This technique is conceptually attractive because its operational physical principle involves a spatial electromagnetic scattering resonance with a single, but selectable, long gravity wave. Multiplexing of signals having different spacing of the two transmitted frequencies allows measurements of the entire long wave ocean spectrum to be carried out. A new scatterometer is developed and experimentally tested which is capable of making measurements having much larger signal/background values than previously possible. This instrument couples the resonance technique with coherent, frequency agility radar capabilities. This scatterometer is presently configured for supporting a program of surface current measurements.

Exact nonlinear command generation and tracking for robot manipulators and spacecraft slewing maneuvers

NASA Technical Reports Server (NTRS)

Dywer, T. A. W., III; Lee, G. K. F.

1984-01-01

In connection with the current interest in agile spacecraft maneuvers, it has become necessary to consider the nonlinear coupling effects of multiaxial rotation in the treatment of command generation and tracking problems. Multiaxial maneuvers will be required in military missions involving a fast acquisition of moving targets in space. In addition, such maneuvers are also needed for the efficient operation of robot manipulators. Attention is given to details regarding the direct nonlinear command generation and tracking, an approach which has been successfully applied to the design of control systems for V/STOL aircraft, linearizing transformations for spacecraft controlled with external thrusters, the case of flexible spacecraft dynamics, examples from robot dynamics, and problems of implementation and testing.

Resonant tunneling spectroscopy of valley eigenstates on a donor-quantum dot coupled system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kobayashi, T., E-mail: t.kobayashi@unsw.edu.au; Heijden, J. van der; House, M. G.

We report on electronic transport measurements through a silicon double quantum dot consisting of a donor and a quantum dot. Transport spectra show resonant tunneling peaks involving different valley states, which illustrate the valley splitting in a quantum dot on a Si/SiO{sub 2} interface. The detailed gate bias dependence of double dot transport allows a first direct observation of the valley splitting in the quantum dot, which is controllable between 160 and 240 μeV with an electric field dependence 1.2 ± 0.2 meV/(MV/m). A large valley splitting is an essential requirement for implementing a physical electron spin qubit in a silicon quantum dot.

Precision diamond grinding of ceramics and glass

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smith, S.; Paul, H.; Scattergood, R.O.

A new research initiative will be undertaken to investigate the effect of machine parameters and material properties on precision diamond grinding of ceramics and glass. The critical grinding depth to initiate the plastic flow-to-brittle fracture regime will be directly measured using plunge-grind tests. This information will be correlated with machine parameters such as wheel bonding and diamond grain size. Multiaxis grinding tests will then be made to provide data more closely coupled with production technology. One important aspect of the material property studies involves measuring fracture toughness at the very short crack sizes commensurate with grinding damage. Short crack toughnessmore » value`s can be much less than the long-crack toughness values measured in conventional fracture tests.« less

Radiation Losses Due to Tapering of a Double-Core Optical Waveguide

NASA Technical Reports Server (NTRS)

Lyons, Donald R.; Khet, Myat; Pencil, Eric (Technical Monitor)

2001-01-01

The theoretical model we designed parameterizes the power losses as a function of .the profile shape for a tapered, single mode, optical dielectric coupler. The focus of this project is to produce a working model that determines the power losses experienced by the fibers when light crosses a taper region. This phenomenon can be examined using coupled mode theory. The optical directional coupler consists of a parallel, dual-channel, waveguide with minimal spacing between the channels to permit energy exchange. Thus, power transfer is essentially a function of the taper profile. To find the fields in the fibers, the approach used was that of solving the Helmholtz equation in cylindrical coordinates involving Bessel and modified Bessel functions depending on the location.

Computer quantitation of coronary angiograms

NASA Technical Reports Server (NTRS)

Ledbetter, D. C.; Selzer, R. H.; Gordon, R. M.; Blankenhorn, D. H.; Sanmarco, M. E.

1978-01-01

A computer technique is being developed at the Jet Propulsion Laboratory to automate the measurement of coronary stenosis. A Vanguard 35mm film transport is optically coupled to a Spatial Data System vidicon/digitizer which in turn is controlled by a DEC PDP 11/55 computer. Programs have been developed to track the edges of the arterial shadow, to locate normal and atherosclerotic vessel sections and to measure percent stenosis. Multiple frame analysis techniques are being investigated that involve on the one hand, averaging stenosis measurements from adjacent frames, and on the other hand, averaging adjacent frame images directly and then measuring stenosis from the averaged image. For the latter case, geometric transformations are used to force registration of vessel images whose spatial orientation changes.

Time-reversing light pulses by adiabatic coupling modulation in coupled-resonator optical waveguides

NASA Astrophysics Data System (ADS)

Wang, Chao; Martini, Rainer; Search, Christopher P.

2012-12-01

We introduce a mechanism to time reverse short optical pulses in coupled resonator optical waveguides (CROWs) by direct modulation of the coupling coefficients between microresonators. The coupling modulation is achieved using phase modulation of a Mach-Zehnder interferometer coupler. We demonstrate that by adiabatic modulation of the coupling between resonators we can time reverse or store light pulses with bandwidths up to a few hundred GHz. The large pulse bandwidths, small device footprint, robustness with respect to resonator losses, and easy tuning process of the coupling coefficients make this method more practical than previous proposals.

The origin of unequal bond lengths in the C 1B 2 state of SO 2: Signatures of high-lying potential energy surface crossings in the low-lying vibrational structure

DOE Office of Scientific and Technical Information (OSTI.GOV)

Park, G. Barratt; Jiang, Jun; Field, Robert W.

Here the C 1B 2 state of SO 2 has a double-minimum potential in the antisymmetric stretch coordinate, such that the minimum energy geometry has nonequivalent SO bond lengths. The asymmetry in the potential energy surface is expressed as a staggering in the energy levels of the v' 3 progression. We have recently made the first observation of low-lying levels with odd quanta of v' 3, which allows us--in the current work--to characterize the origins of the level staggering. Our work demonstrates the usefulness of low-lying vibrational level structure, where the character of the wavefunctions can be relatively easily understood,more » to extract information about dynamically important potential energy surface crossings that occur at much higher energy. The measured staggering pattern is consistent with a vibronic coupling model for the double-minimum, which involves direct coupling to the bound 2 1A 1 state and indirect coupling with the repulsive 3 1A 1 state. The degree of staggering in the v' 3 levels increases with quanta of bending excitation, which is consistent with the approach along the C state potential energy surface to a conical intersection with the 2 1A 1 surface at a bond angle of ~145°.« less

Dynamics modeling and vibration analysis of a piezoelectric diaphragm applied in valveless micropump

NASA Astrophysics Data System (ADS)

He, Xiuhua; Xu, Wei; Lin, Nan; Uzoejinwa, B. B.; Deng, Zhidan

2017-09-01

This paper presents the dynamical model involved with load of fluid pressure, electric-solid coupling simulation and experimental performance of the piezoelectric diaphragm fabricated and applied in valveless micropump. The model is based on the theory of plate-shell with small deflection, considering the two-layer structure of piezoelectric ceramic and elastic substrate. The high-order non-homogeneous vibration equation of the piezoelectric diaphragm, derived in the course of the study, was solved by being divided into a homogeneous Bessel equation and a non-homogeneous static equation according to the superposition principle. The amplitude of the piezoelectric diaphragm driven by sinusoidal voltage against the load of fluid pressure was obtained from the solution of the vibration equation. Also, finite element simulation of electric-solid coupling between displacement of piezoelectric diaphragm due to an applied voltage and resulting deformation of membrane was considered. The simulation result showed that the maximum deflection of diaphragm is 9.51 μm at a quarter cycle time when applied a peak-to-peak voltage of 150VP-P with a frequency of 90 Hz, and the displacement distribution according to the direction of the radius was demonstrated. Experiments were performed to verify the prediction of the dynamic modeling and the coupling simulation, the experimental data showed a good agreement with the dynamical model and simulation.

Enzymes as modular catalysts for redox half-reactions in H2-powered chemical synthesis: from biology to technology.

PubMed

Reeve, Holly A; Ash, Philip A; Park, HyunSeo; Huang, Ailun; Posidias, Michalis; Tomlinson, Chloe; Lenz, Oliver; Vincent, Kylie A

2017-01-15

The present study considers the ways in which redox enzyme modules are coupled in living cells for linking reductive and oxidative half-reactions, and then reviews examples in which this concept can be exploited technologically in applications of coupled enzyme pairs. We discuss many examples in which enzymes are interfaced with electronically conductive particles to build up heterogeneous catalytic systems in an approach which could be termed synthetic biochemistry We focus on reactions involving the H + /H 2 redox couple catalysed by NiFe hydrogenase moieties in conjunction with other biocatalysed reactions to assemble systems directed towards synthesis of specialised chemicals, chemical building blocks or bio-derived fuel molecules. We review our work in which this approach is applied in designing enzyme-modified particles for H 2 -driven recycling of the nicotinamide cofactor NADH to provide a clean cofactor source for applications of NADH-dependent enzymes in chemical synthesis, presenting a combination of published and new work on these systems. We also consider related photobiocatalytic approaches for light-driven production of chemicals or H 2 as a fuel. We emphasise the techniques available for understanding detailed catalytic properties of the enzymes responsible for individual redox half-reactions, and the importance of a fundamental understanding of the enzyme characteristics in enabling effective applications of redox biocatalysis. © 2017 The Author(s).

Realistic anomaly-mediated supersymmetry breaking

NASA Astrophysics Data System (ADS)

Chacko, Zacharia; Luty, Markus A.; Maksymyk, Ivan; Pontón, Eduardo

2000-03-01

We consider supersymmetry breaking communicated entirely by the superconformal anomaly in supergravity. This scenario is naturally realized if supersymmetry is broken in a hidden sector whose couplings to the observable sector are suppressed by more than powers of the Planck scale, as occurs if supersymmetry is broken in a parallel universe living in extra dimensions. This scenario is extremely predictive: soft supersymmetry breaking couplings are completely determined by anomalous dimensions in the effective theory at the weak scale. Gaugino and scalar masses are naturally of the same order, and flavor-changing neutral currents are automatically suppressed. The most glaring problem with this scenario is that slepton masses are negative in the minimal supersymmetric standard model. We point out that this problem can be simply solved by coupling extra Higgs doublets to the leptons. Lepton flavor-changing neutral currents can be naturally avoided by approximate symmetries. We also describe more speculative solutions involving compositeness near the weak scale. We then turn to electroweak symmetry breaking. Adding an explicit μ term gives a value for Bμ that is too large by a factor of ~ 100. We construct a realistic model in which the μ term arises from the vacuum expectation value of a singlet field, so all weak-scale masses are directly related to m3/2. We show that fully realistic electroweak symmetry breaking can occur in this model with moderate fine-tuning.