Science.gov

Sample records for complete variable loop

  1. Complete renormalization of QCD at five loops

    NASA Astrophysics Data System (ADS)

    Luthe, Thomas; Maier, Andreas; Marquard, Peter; Schröder, York

    2017-03-01

    We present new analytical five-loop Feynman-gauge results for the anomalous dimensions of ghost field and -vertex, generalizing the known values for SU(3) to a general gauge group. Together with previously published results on the quark mass and -field anomalous dimensions and the Beta function, this completes the 5-loop renormalization program of gauge theories in that gauge.

  2. Effect of partial and complete variable loop deletions of the human immunodeficiency virus type 1 envelope glycoprotein on the breadth of gp160-specific immune responses.

    PubMed

    Gzyl, Jaroslaw; Bolesta, Elizabeth; Wierzbicki, Andrew; Kmieciak, Dariusz; Naito, Toshio; Honda, Mitsuo; Komuro, Katsutoshi; Kaneko, Yutaro; Kozbor, Danuta

    2004-01-20

    Induction of cross-reactive cellular and humoral responses to the HIV-1 envelope (env) glycoprotein was examined after DNA immunization of BALB/c mice with gp140(89.6)-derived constructs exhibiting partial or complete deletions of the V1, V2, and V3 domains. It was demonstrated that specific modification of the V3 loop (mV3) in combination with the V2-modified (mV2) or V1/V2-deleted (DeltaV1/V2) region elicited increased levels of cross-reactive CD8(+) T cell responses. Mice immunized with the mV2/mV3 or DeltaV1/V2/mV3 gp140(89.6) plasmid DNA were greater than 50-fold more resistant to challenge with recombinant vaccinia virus (rVV) expressing heterologous env gene products than animals immunized with the wild-type (WT) counterpart. Sera from mV2/mV3- and DeltaV1/V2/mV3-immunized mice exhibited the highest cross-neutralizing activity and displayed intermediate antibody avidity values which were further enhanced by challenge with rVV expressing the homologous gp160 glycoprotein. In contrast, complete deletion of the variable regions had little or no effect on the cross-reactive antibody responses. The results of these experiments indicate that the breadth of antibody responses to the HIV-1 env glycoprotein may not be increased by removal of the variable domains. Instead, partial deletions within these regions may redirect specific responses toward conserved epitopes and facilitate approaches for boosting cross-reactive cellular and antibody responses to the env glycoprotein.

  3. Loop Variables in String Theory

    NASA Astrophysics Data System (ADS)

    Sathiapalan, B.

    The loop variable approach is a proposal for a gauge-invariant generalization of the sigma-model renormalization group method of obtaining equations of motion in string theory. The basic guiding principle is space-time gauge invariance rather than world sheet properties. In essence it is a version of Wilson's exact renormalization group equation for the world sheet theory. It involves all the massive modes and is defined with a finite world sheet cutoff, which allows one to go off the mass-shell. On shell the tree amplitudes of string theory are reproduced. The equations are gauge-invariant off shell also. This paper is a self-contained discussion of the loop variable approach as well as its connection with the Wilsonian RG.

  4. Active region coronal loops - Structural and variability

    NASA Technical Reports Server (NTRS)

    Haisch, Bernhard M.; Strong, Keith T.; Harrison, Richard A.; Gary, G. A.

    1988-01-01

    X-ray images of a pair of active region loops are studied which show significant, short time-scale variability in the line fluxes of O VIII, Ne IX, and Mg XI and in the 3.5-11.5 keV soft X-ray bands. Vector magnetograms and high-resolution UV images were used to model the three-dimensional characteristics of the loops. X-ray light curves were generated spanning four consecutive orbits for both loops individually, and light curves of the loop tops and brightest points were also generated. The largest variations involve flux changes of up to several hundred percent on time scales of 10 minutes. No significant H-alpha flare activity is reported, and loop temperatures remain in the four to six million K range. The decay phases of the light curves indicate radiative cooling, inhibition of conduction, and some type of 'continued heating' due to ongoing, underlying activity at the microflare level.

  5. Orion Suit Loop Variable Pressure Regulator Development

    NASA Technical Reports Server (NTRS)

    Mosher, Michael; Lewis, John F.; Campbell, Melissa

    2012-01-01

    The Orion Multi Purpose Crew Vehicle (MPCV) integrates the cabin and pressure suits with the core life support systems to provide life support during contingency depressurized cabin operations. To provide the multiple suit pressures between nominal pressurized cabin suited operations, suit leak checks, depressurized cabin suited operations, and elevated suit pressure for denitrification, a variable pressure regulator is needed. This paper documents the development of the suit loop regulator for Orion.

  6. Complete maps of molecular-loop conformational spaces.

    PubMed

    Porta, Josep M; Ros, Lluís; Thomas, Federico; Corcho, Francesc; Cantó, Josep; Pérez, Juan Jesús

    2007-10-01

    This paper presents a numerical method to compute all possible conformations of distance-constrained molecular loops, i.e., loops where some interatomic distances are held fixed, while others can vary. The method is general (it can be applied to single or multiple intermingled loops of arbitrary topology) and complete (it isolates all solutions, even if they form positive-dimensional sets). Generality is achieved by reducing the problem to finding all embeddings of a set of points constrained by pairwise distances, which can be formulated as computing the roots of a system of Cayley-Menger determinants. Completeness is achieved by expressing these determinants in Bernstein form and using a numerical algorithm that exploits such form to bound all root locations at any desired precision. The method is readily parallelizable, and the current implementation can be run on single- or multiprocessor machines. Experiments are included that show the method's performance on rigid loops, mobile loops, and multiloop molecules. In all cases, complete maps including all possible conformations are obtained, thus allowing an exhaustive analysis and visualization of all pseudo-rotation paths between different conformations satisfying loop closure.

  7. Completely inverted hysteresis loops: Inhomogeneity effects or experimental artifacts

    SciTech Connect

    Song, C. Cui, B.; Pan, F.; Yu, H. Y.

    2013-11-14

    Completely inverted hysteresis loops (IHL) are obtained by the superconducting quantum interference device with large cooling fields (>10 kOe) in (La,Sr)MnO{sub 3} films with self-assembled LaSrMnO{sub 4}, an antiferromagnetic interface. Although the behaviours of measured loops show many features characteristic to the IHL, its origin, however, is not due to the exchange coupling between (La,Sr)MnO{sub 3}/LaSrMnO{sub 4}, an often accepted view on IHL. Instead, we demonstrate that the negative remanence arises from the hysteresis of superconducting coils, which drops abruptly when lower cooling fields are utilized. Hence the completely inverted hysteresis loops are experimental artifacts rather than previously proposed inhomogeneity effects in complicated materials.

  8. Variables Associated with Successful Probation Completion.

    ERIC Educational Resources Information Center

    Morgan, Kathryn D.

    1995-01-01

    Examines variables related to successful probation completion among 266 Tennessee felony probationers whose cases had been closed due to completion, revocation, absconsion, or sentence for a new offense. The variables of marital status, employment, educational attainment, gender, prior criminal record, level of supervision, and length of…

  9. Complete 1-loop test of AdS/CFT

    NASA Astrophysics Data System (ADS)

    Gromov, Nikolay; Vieira, Pedro

    2008-04-01

    We analyze nested Bethe ansatz (NBA) and the corresponding finite size corrections. We find an integral equation which describes these corrections in a closed form. As an application we considered the conjectured Beisert-Staudacher (BS) equations with the Hernandez-Lopez dressing factor where the finite size corrections should reproduce generic one (worldsheet) loop computations around any classical superstring motion in the AdS5 × S5 background with exponential precision in the large angular momentum of the string states. Indeed, we show that our integral equation can be interpreted as a sum over all physical fluctuations and thus prove the complete 1-loop consistency of the BS equations. In other words we demonstrate that any local conserved charge (including the AdS Energy) computed from the BS equations is indeed given at 1-loop by the sum of charges of fluctuations up to exponentially suppressed contributions in the large angular momentum os the string states. We also point out where precisely we loose the exponential terms in our ab initio analysis. Contrary to all previous studies of finite size corrections, which were limited to simple configurations inside rank 1 subsectors, our treatment is completely general.

  10. Gulf of Mexico Loop Current path variability

    NASA Astrophysics Data System (ADS)

    Donohue, K. A.; Watts, D. R.; Hamilton, P.; Leben, R.; Kennelly, M.; Lugo-Fernández, A.

    2016-12-01

    Loop Current, LC, path variability exhibits a continuum of spatial and temporal scales, all are called meanders in this work. They arise from a variety of processes, including short and long waves, frontal eddies with or without closed cores and developing baroclinic instability. They have been extensively studied with satellite sea surface temperature SST, and height, SSH. Yet, these systems provide an incomplete view into LC meandering: SST measurements are hampered by cloud coverage and low thermal contrast in summer months and SSH measurements by altimeter temporal and spatial resolution. In an effort to resolve LC meander temporal and spatial scales, they are investigated using a mesoscale resolving in situ array deployed in the Gulf of Mexico. The array, which consisted of twenty-five inverted echo sounders with pressure gauges, PIES, and current meter moorings, was deployed April 2009 and recovered in October-November 2011. The broad extent of the array, nominally 89° W to 85° W, 25° N to 27° N, enabled quantitative mapping of the regional circulation. LC meander properties are characterized as a function of spatial distribution of energy, frequency, wavenumber, and phase speed. Dispersion characteristics and meander scales are comparable to those found in the Gulf Stream. Phase speeds increase with frequency and range from 8 to 50 km d-1. Wavelengths associated with each band are as follows: 460 km for the 100 to 40 d band, 350 km for the 40 to 20 d band, 270 km for the 20 to 10 d band and 230 km for the 10 to 3 d band. The strongest variability is in the 100 to 40 d band. Spatially the 100 to 40 d variability is concentrated to east of the Mississippi Fan, growing and propagating downstream along the eastern portion of the LC. Meanders between 40 and 20 d propagate along the full encompassed length of the LC. Their temporal amplitudes peak at the time of LC eddy detachment and separation. Meanders with shorter periods than 20 d do not always propagate

  11. Complete two-loop binding correction to the Lamb shift

    SciTech Connect

    Pachucki, K. )

    1994-05-16

    The binding correction of the two-loop contribution to the Lamb shift in hydrogenlike atoms is calculated by a combined analytical and numerical method. A new theoretical value for the Lamb shift is given and the proton radius puzzle is solved in favor of the value obtained by the Mainz group.

  12. Loop quantum cosmology with self-dual variables

    NASA Astrophysics Data System (ADS)

    Wilson-Ewing, Edward

    2015-12-01

    Using the complex-valued self-dual connection variables, the loop quantum cosmology of a closed Friedmann space-time coupled to a massless scalar field is studied. It is shown how the reality conditions can be imposed in the quantum theory by choosing a particular inner product for the kinematical Hilbert space. While holonomies of the self-dual Ashtekar connection are not well defined in the kinematical Hilbert space, it is possible to introduce a family of generalized holonomylike operators of which some are well defined; these operators in turn are used in the definition of the Hamiltonian constraint operator where the scalar field can be used as a relational clock. The resulting quantum theory is closely related, although not identical, to standard loop quantum cosmology constructed from the Ashtekar-Barbero variables with a real Immirzi parameter. Effective Friedmann equations are derived which provide a good approximation to the full quantum dynamics for sharply peaked states whose volume remains much larger than the Planck volume, and they show that for these states quantum gravity effects resolve the big-bang and big-crunch singularities and replace them by a nonsingular bounce. Finally, the loop quantization in self-dual variables of a flat Friedmann space-time is recovered in the limit of zero spatial curvature and is identical to the standard loop quantization in terms of the real-valued Ashtekar-Barbero variables.

  13. Observation of complete inversion of the hysteresis loop in a bimodal magnetic thin film

    NASA Astrophysics Data System (ADS)

    Maity, Tuhin; Kepaptsoglou, Demie; Schmidt, Michael; Ramasse, Quentin; Roy, Saibal

    2017-03-01

    The existence of inverted hysteresis loops (IHLs) in magnetic materials is still in debate due to the lack of direct evidence and convincing theoretical explanations. Here we report the direct observation and physical interpretation of complete IHL in N i45F e55 films with 1 to 2 nm thin N i3Fe secondary phases at the grain boundaries. The origin of the inverted loop, however, is shown to be due to the exchange bias coupling between N i45F e55 and N i3Fe , which can be broken by the application of a high magnetic field. A large positive exchange bias (HE B=14 ×HC) is observed in the NiFe composite material giving novel insight into the formation of a noninverted hysteresis loop (non-IHL) and IHL, which depend on the loop tracing field range (HR). The crossover from non-IHL to IHL is found to be at 688 Oe.

  14. Anisotropic loop quantum cosmology with self-dual variables

    NASA Astrophysics Data System (ADS)

    Wilson-Ewing, Edward

    2016-04-01

    A loop quantization of the diagonal class A Bianchi models starting from the complex-valued self-dual connection variables is presented in this paper. The basic operators in the quantum theory correspond to areas and generalized holonomies of the Ashtekar connection, and the reality conditions are implemented via the choice of the inner product on the kinematical Hilbert space. The action of the Hamiltonian constraint operator is given explicitly for the case when the matter content is a massless scalar field (in which case the scalar field can be used as a relational clock), and it is shown that the big bang and big crunch singularities are resolved in the sense that singular and nonsingular states decouple under the action of the Hamiltonian constraint operator.

  15. Long-term variability of a complete sample of quasars

    SciTech Connect

    Cristiani, S.; Vio, R.; Andreani, P. )

    1990-07-01

    The long-term variability of a complete sample of quasars selected in the field of the SA 94 has been investigated. Using Schmidt plates covering a time baseline of seven years, about one-third of the quasars are found to be variable. It is suggested that all the quasi-stellar objects are variable with amplitudes of a few tenths of a magnitude on timescales of the order of some years in their restframes. The application of the variability technique to the selection of complete samples of quasars is discussed. The timescales estimated can be easily accounted for in the accreting black hole with thermal and viscous timescales. The variability is found to be correlated with the absolute magnitude and/or the redshift. 21 refs.

  16. The Complete Four-Loop Four-Point Amplitude in N

    SciTech Connect

    Bern, Z.; Carrasco, J.J.M.; Dixon, Lance J.; Johansson, H.; Roiban, R.; /Penn State U.

    2010-08-25

    We present the complete four-loop four-point amplitude in N = 4 super-Yang-Mills theory, for a general gauge group and general D-dimensional covariant kinematics, and including all non-planar contributions. We use the method of maximal cuts - an efficient application of the unitarity method - to construct the result in terms of 50 four-loop integrals. We give graphical rules, valid in D-dimensions, for obtaining various non-planar contributions from previously-determined terms. We examine the ultraviolet behavior of the amplitude near D = 11/2. The non-planar terms are as well-behaved in the ultraviolet as the planar terms. However, in the color decomposition of the three- and four-loop amplitude for an SU(N{sub c}) gauge group, the coefficients of the double-trace terms are better behaved in the ultraviolet than are the single-trace terms. The results from this paper were an important step toward obtaining the corresponding amplitude in N = 8 supergravity, which confirmed the existence of cancellations beyond those needed for ultraviolet finiteness at four loops in four dimensions. Evaluation of the loop integrals near D = 4 would permit tests of recent conjectures and results concerning the infrared behavior of four-dimensional massless gauge theory.

  17. The complete two-loop integrated jet thrust distribution in soft-collinear effective theory

    SciTech Connect

    von Manteuffel, Andreas; Schabinger, Robert M.; Zhu, Hua Xing

    2014-03-01

    In this work, we complete the calculation of the soft part of the two-loop integrated jet thrust distribution in e+e- annihilation. This jet mass observable is based on the thrust cone jet algorithm, which involves a veto scale for out-of-jet radiation. The previously uncomputed part of our result depends in a complicated way on the jet cone size, r, and at intermediate stages of the calculation we actually encounter a new class of multiple polylogarithms. We employ an extension of the coproduct calculus to systematically exploit functional relations and represent our results concisely. In contrast to the individual contributions, the sum of all global terms can be expressed in terms of classical polylogarithms. Our explicit two-loop calculation enables us to clarify the small r picture discussed in earlier work. In particular, we show that the resummation of the logarithms of r that appear in the previously uncomputed part of the two-loop integrated jet thrust distribution is inextricably linked to the resummation of the non-global logarithms. Furthermore, we find that the logarithms of r which cannot be absorbed into the non-global logarithms in the way advocated in earlier work have coefficients fixed by the two-loop cusp anomalous dimension. We also show that in many cases one can straightforwardly predict potentially large logarithmic contributions to the integrated jet thrust distribution at L loops by making use of analogous contributions to the simpler integrated hemisphere soft function.

  18. The muon magnetic moment in the 2HDM: complete two-loop result

    NASA Astrophysics Data System (ADS)

    Cherchiglia, Adriano; Kneschke, Patrick; Stöckinger, Dominik; Stöckinger-Kim, Hyejung

    2017-01-01

    We study the 2HDM contribution to the muon anomalous magnetic moment a μ and present the complete two-loop result, particularly for the bosonic contribution. We focus on the Aligned 2HDM, which has general Yukawa couplings and contains the type I, II, X, Y models as special cases. The result is expressed with physical parameters: three Higgs boson masses, Yukawa couplings, two mixing angles, and one quartic potential parameter. We show that the result can be split into several parts, each of which has a simple parameter dependence, and we document their general behavior. Taking into account constraints on parameters, we find that the full 2HDM contribution to a μ can accommodate the current experimental value, and the complete two-loop bosonic contribution can amount to (2⋯4) × 10-10, more than the future experimental uncertainty.

  19. Black holes in loop quantum gravity: the complete space-time.

    PubMed

    Gambini, Rodolfo; Pullin, Jorge

    2008-10-17

    We consider the quantization of the complete extension of the Schwarzschild space-time using spherically symmetric loop quantum gravity. We find an exact solution corresponding to the semiclassical theory. The singularity is eliminated but the space-time still contains a horizon. Although the solution is known partially numerically and therefore a proper global analysis is not possible, a global structure akin to a singularity-free Reissner-Nordström space-time including a Cauchy horizon is suggested.

  20. 318-MHz variability of complete samples of extragalactic radio sources

    NASA Technical Reports Server (NTRS)

    Dennison, B.; Broderick, J. J.; Ledden, J. E.; Odell, S. L.; Condon, J. J.

    1981-01-01

    It is found by a low-frequency variability survey, involving two- and three-epoch, 318-MHz observations of extragalactic sources in samples complete to 3 Jy at 1400 MHz and 1 Jy at 5000 MHz, that steep-spectrum sources do not seem to vary while all flat-spectrum sources exhibit low-frequency variability greater than 8% over about 5 yr. It is also found that the flat-spectrum sources with inverted spectra show the largest fractional variations, and that there is a correlation between the incidence of low-frequency variability and the determination that a source is an optically violent variable. These statistical properties are consistent with models which invoke radio and optical emission relativistic beaming.

  1. Advanced Photovoltaic Inverter Functionality using 500 kW Power Hardware-in-Loop Complete System Laboratory Testing: Preprint

    SciTech Connect

    Mather, B. A.; Kromer, M. A.; Casey, L.

    2013-01-01

    With the increasing penetration of distribution connected photovoltaic (PV) systems, more and more PV developers and utilities are interested in easing future PV interconnection concerns by mitigating some of the impacts of PV integration using advanced PV inverter controls and functions. This paper describes the testing of a 500 kW PV inverter using Power Hardware-in-Loop (PHIL) testing techniques. The test setup is described and the results from testing the inverter in advanced functionality modes, not commonly used in currently interconnected PV systems, are presented. PV inverter operation under PHIL evaluation that emulated both the DC PV array connection and the AC distribution level grid connection are shown for constant power factor (PF) and constant reactive power (VAr) control modes. The evaluation of these modes was completed under varying degrees of modeled PV variability.

  2. Complete spectrum of long operators in Script N = 4 SYM at one loop

    NASA Astrophysics Data System (ADS)

    Beisert, Niklas; Kazakov, Vladimir A.; Sakai, Kazuhiro; Zarembo, Konstantin

    2005-07-01

    We construct the complete spectral curve for an arbitrary local operator, including fermions and covariant derivatives, of one-loop Script N = 4 gauge theory in the thermodynamic limit. This curve perfectly reproduces the Frolov-Tseytlin limit of the full spectral curve of classical strings on AdS5 × S5 derived in [64]. To complete the comparison we introduce stacks, novel bound states of roots of different flavors which arise in the thermodynamic limit of the corresponding Bethe ansatz equations. We furthermore show the equivalence of various types of Bethe equations for the underlying fraktur sfraktur u(2,2|4) superalgebra, in particular of the type ``Beauty'' and ``Beast''.

  3. An embedding of loop quantum cosmology in (b,v) variables into a full theory context

    NASA Astrophysics Data System (ADS)

    Bodendorfer, N.

    2016-06-01

    Loop quantum cosmology in (b, v) variables, which is governed by a unit step size difference equation, is embedded into a full theory context based on similar variables. A full theory context here means a theory of quantum gravity arrived at using the quantisation techniques used in loop quantum gravity, however based on a different choice of elementary variables and classical gauge fixing suggested by loop quantum cosmology. From the full theory perspective, the symmetry reduction is characterised by the vanishing of certain phase space functions which are implemented as operator equations in the quantum theory. The loop quantum cosmology dynamics arise as the action of the full theory Hamiltonian on maximally coarse states in the kernel of the reduction constraints. An application of this reduction procedure to spherical symmetry is also sketched, with similar results, but only one canonical pair in (b, v) form.

  4. Loop Heat Pipe with Thermal Control Valve as a Variable Thermal Link

    NASA Technical Reports Server (NTRS)

    Hartenstine, John; Anderson, William G.; Walker, Kara; Dussinger, Pete

    2012-01-01

    Future lunar landers and rovers will require variable thermal links that allow for heat rejection during the lunar daytime and passively prevent heat rejection during the lunar night. During the lunar day, the thermal management system must reject the waste heat from the electronics and batteries to maintain them below the maximum acceptable temperature. During the lunar night, the heat rejection system must either be shut down or significant amounts of guard heat must be added to keep the electronics and batteries above the minimum acceptable temperature. Since guard heater power is unfavorable because it adds to system size and complexity, a variable thermal link is preferred to limit heat removal from the electronics and batteries during the long lunar night. Conventional loop heat pipes (LHPs) can provide the required variable thermal conductance, but they still consume electrical power to shut down the heat transfer. This innovation adds a thermal control valve (TCV) and a bypass line to a conventional LHP that proportionally allows vapor to flow back into the compensation chamber of the LHP. The addition of this valve can achieve completely passive thermal control of the LHP, eliminating the need for guard heaters and complex controls.

  5. Geodesic completeness and the lack of strong singularities in effective loop quantum Kantowski-Sachs spacetime

    NASA Astrophysics Data System (ADS)

    Saini, Sahil; Singh, Parampreet

    2016-12-01

    Resolution of singularities in the Kantowski-Sachs model due to non-perturbative quantum gravity effects is investigated. Using the effective spacetime description for the improved dynamics version of loop quantum Kantowski-Sachs spacetimes, we show that even though expansion and shear scalars are universally bounded, there can exist events where curvature invariants can diverge. However, such events can occur only for very exotic equations of state when pressure or derivatives of energy density with respect to triads become infinite at a finite energy density. In all other cases curvature invariants are proved to remain finite for any evolution in finite proper time. We find the novel result that all strong singularities are resolved for arbitrary matter. Weak singularities pertaining to above potential curvature divergence events can exist. The effective spacetime is found to be geodesically complete for particle and null geodesics in finite time evolution. Our results add to a growing evidence for generic resolution of strong singularities using effective dynamics in loop quantum cosmology by generalizing earlier results on isotropic and Bianchi-I spacetimes.

  6. Improving the Standard of Orthopaedic Operation Documentation Using Typed Proforma Operation Notes: A Completed Audit Loop

    PubMed Central

    Ellanti, Prasad; Moriarty, Andrew; McAuley, Nuala; Hogan, Niall

    2017-01-01

    Introduction The Royal College of Surgeons (RCS) published Good Surgical Practice guidelines in 2008 and revised them in 2014. They outline the basic standard that all surgical operation notes should meet. Objectives To retrospectively audit 57 typed orthopaedic operation notes from St. James’s Hospital in Dublin (from August to November 2015) against the RCS Good Surgical Practice guidelines published in 2014. They were then compared with the department’s previous audit of handwritten notes to complete the audit loop. Materials and methods A total of 57 orthopaedic operation notes were audited by a single reviewer. They were prospectively collected between August and November 2015. All notes were typed on the standard St. James’s Hospital operation note proforma. Results Of the surgeries, 89.5% were emergencies with 77.2% of them being performed by trainees. All of the operation notes were typed and signed by trainees. The procedure name, incision and closure details, tourniquet time (when relevant), and postoperative instructions were documented in 100% of the notes. In total, 80.7% had an operative diagnosis included while only 26.9% of the documentation had prosthesis serial numbers. All of the typed notes were deemed to be legible. Conclusion The use of printed operation notes allows for improved legibility when compared to typed notes. Documentation standards remained very high in the same areas as the handwritten notes and a marked improvement was seen in areas that had been poorly documented.

  7. Effect of Variable Emittance Coatings on the Operation of a Miniature Loop Heat Pipe

    NASA Technical Reports Server (NTRS)

    Douglas, Donya M.; Ku, Jentung; Ottenstein, Laura; Swanson, Theodore; Hess, Steve; Darrin, Ann

    2005-01-01

    Abstract. As the size of spacecraft shrink to accommodate small and more efficient instruments, smaller launch vehicles, and constellation missions, all subsystems must also be made smaller. Under NASA NFL4 03-OSS-02, Space Technology-8 (ST 8), NASA Goddard Space Flight Center and Jet Propulsion Laboratory jointly conducted a Concept Definition study to develop a miniature loop heat pipe (MLHP) thermal management system design suitable for future small spacecraft. The proposed MLHP thermal management system consists of a miniature loop heat pipe (LHP) and deployable radiators that are coated with variable emittance coatings (VECs). As part of the Phase A study and proof of the design concept, variable emittance coatings were integrated with a breadboard miniature loop heat pipe. The miniature loop heat pipe was supplied by the Jet Propulsion Laboratory (PL), while the variable emittance technology were supplied by Johns Hopkins University Applied Physics Laboratory and Sensortex, Inc. The entire system was tested under vacuum at various temperature extremes and power loads. This paper summarizes the results of this testing and shows the effect of the VEC on the operation of a miniature loop heat pipe.

  8. Complete mitochondrial genome of Ptychobarbus kaznakovi (Teleostei: Cypriniformes: Cyprinidae), and repetitive sequences in the D-loop.

    PubMed

    Ma, Qingzhan; Wu, Bo; Li, Jiuxuan; Song, Zhaobin

    2016-05-01

    The complete mitochondrial DNA genome of Ptychobarbus kaznakovi was sequenced and characterized. The genome is 16,842 bp in length. Similar with most teleosts, it has two ribosomal RNA (rRNA) genes, 13 protein-coding genes, 22 transfer RNA (tRNA) genes, and one displacement loop (D-loop) region. Conserved sequence blocks, including ETAS, CSB-B, D, E, F, and CSB1-3, were identified in the D-loop, which is similar to other species in Cypriniformes. Nevertheless, a 55 bp tandem repeat array was also identified at 3' end of the D-loop, which is the first finding in Schizothoracinae. Phylogenetic analysis showed that the species of Ptychobarbus (P. dipogon and P. kaznakovi) formed a monophyletic group and represented close relationship to the species without scales in Schizothoracinae.

  9. Variable-Length Message Transmission for Distributed Loop Computer Networks (Part I).

    ERIC Educational Resources Information Center

    Reames, C. C.; Liu, M. T.

    An introduction to the problems of variable-length message transmission in distributed loop computer networks, with a summary of previous accomplishments in the area, begins this technically-oriented document. An improved technique, overcoming some of the inadequacies in presently used techniques, is proposed together with a conceptual model of…

  10. Evaluation of left ventricular assist device performance and hydraulic force in a complete mock circulation loop.

    PubMed

    Timms, Daniel; Hayne, Mark; Tan, Andy; Pearcy, Mark

    2005-07-01

    Centrifugal pump performance characteristics are vital in determining the ability of a prototype left ventricular assist device (LVAD) to meet the physiological circulation requirements of the cardiovascular system. These characteristics influence the static hydraulic forces encountered by the pump impeller, which determine the required load stiffness of suspension type bearings to minimize impeller touchdown. Performance investigations were conducted on an LVAD design while characterizing the impeller static hydraulic forces of various impeller/volute configurations. The pumps were inserted into a complete systemic and pulmonary mock circulation rig configured to provide suitable nonpulsatile or simulated pulsatile left heart failure environments. The single volute and closed shroud impeller configuration exhibited lowest radial (0.01 N) and axial (3 N) force at nonpulsatile design flow conditions, respectively. Normal hemodynamic conditions of 5.1 L/min at 94 mm Hg were re-established upon inserting the device into the left heart failure environment, where the pump operated along the nonpulsatile characteristic curve for 2200 rpm. The operational limits on this curve were dictated by the required pressure differential across the pump during systolic and diastolic periods. The reduction of left atrial pressure (25 to 8 mm Hg) indicated the alleviation of pulmonary congestion. The ability for the LVAD to support circulation in a left heart failure environment was successfully demonstrated in the mock circulation loop. The impeller hydraulic force characteristics attained will aid the bearing designer to select the best volute and impeller configuration to minimize impeller touchdown in magnetic, hydrodynamic or mechanical type bearing applications.

  11. Electrical engineering and nontechnical design variables of multiple inductive loop systems for auditoriums.

    PubMed

    Alterovitz, Gil

    2004-01-01

    This research analyzed both engineering and nontechnical issues involved in the use of Induction Loop Amplification (ILA) devices in auditoriums or large gathering places for hard-of-hearing individuals. A variety of parameters need to be taken into account to determine an optimal shape/configuration for the ILA device. In many cases, an optimal configuration is different from those proposed for classroom use (Ross, 1969; Hodgson, 1986; Clevenger, 1992). Experimental results were obtained for a double-loop configuration in such a setting (a university gymnasium/auditorium in this case). The results demonstrate that a double-loop configuration is a viable possibility for auditorium use. Several variables using this configuration were examined, and experimentation was done. Various implications, including consequent nontechnical issues specific to this application, are discussed as well. Technical and nontechnical aspects of the ILA configuration need to be examined together when designing an optimal system.

  12. Using principal component analysis to find correlations between loop-related and thermodynamic variables for G-quadruplex-forming sequences.

    PubMed

    Jaumot, Joaquim; Gargallo, Raimundo

    2010-08-01

    The application of Principal Component Analysis (PCA) is proposed here as a simple means of revealing correlations between thermodynamic variables corresponding to folding equilibria of intramolecular G-quadruplexes and Watson-Crick duplexes, and the length of loops in the corresponding guanine-rich DNA sequences. To this end, two previously studied data sets were analyzed (Arora and Maiti, J. Phys. Chem. B. 2009 and Kumar and Maiti, Nucleic Acids. Res. 2008). All of the sequences considered shared the common structure 5'- GGG - loop1 - GGG - loop2 - GGG - loop3 - GGG -3'. PCA of these data sets supported a series of correlations between the variables studied. First, the association of loop length with thermodynamic stability and quadruplex structure was corroborated. Secondly, it is proposed that the addition of ethylene glycol produces a stronger stabilization on those sequences showing long loop1 and/or loop3. Thirdly, it is proposed that a low content of adenine in loop1 and/or loop3 will produce an increase in the stability of G-quadruplex and its related Watson-Crick duplex.

  13. Visitor survey results for the Souris River Loop National Wildlife Refuges: Completion report

    USGS Publications Warehouse

    Sexton, Natalie R.; Koontz, Lynne; Stewart, Susan C.

    2005-01-01

    In support of the CCP planning effort for the Souris River Loop Refuges, the Policy Analysis and Science Assistance Branch/Fort Collins Science Center (PASA) of the U.S. Geological Survey conducted visitor surveys at three refuges in North Dakota: Des Lacs, J. Clark Salyer, and Upper Souris National Wildlife Refuges. This research was conducted in order to assess visitor experience, perceptions, and preferences and visitor spending related to recreation on these public lands. This baseline information and input is needed by the refuges to inform their CCP process. Specifically, this survey research assesses the characteristics of visitors and their trips, the activities in which visitors engage while on the refuge, details regarding their trip experience, as well as their preferences and attitudes about various management features, including existing and future conditions. 

  14. Exploring the Structure-Function Loop Adaptability of a (β/α)(8)-Barrel Enzyme through Loop Swapping and Hinge Variability.

    PubMed

    Ochoa-Leyva, Adrián; Barona-Gómez, Francisco; Saab-Rincón, Gloria; Verdel-Aranda, Karina; Sánchez, Filiberto; Soberón, Xavier

    2011-08-05

    Evolution of proteins involves sequence changes that are frequently localized at loop regions, revealing their important role in natural evolution. However, the development of strategies to understand and imitate such events constitutes a challenge to design novel enzymes in the laboratory. In this study, we show how to adapt loop swapping as semiautonomous units of functional groups in an enzyme with the (β/α)(8)-barrel and how this functional adaptation can be measured in vivo. To mimic the natural mechanism providing loop variability in antibodies, we developed an overlap PCR strategy. This includes introduction of sequence diversity at two hinge residues, which connect the new loops with the rest of the protein scaffold, and we demonstrate that this is necessary for a successful exploration of functional sequence space. This design allowed us to explore the sequence requirements to functional adaptation of each loop replacement that may not be sampled otherwise. Libraries generated following this strategy were evaluated in terms of their folding competence and their functional proficiency, an observation that was formalized as a Structure-Function Loop Adaptability value. Molecular details about the function and structure of some variants were obtained by enzyme kinetics and circular dichroism. This strategy yields functional variants that retain the original activity at higher frequencies, suggesting a new strategy for protein engineering that incorporates a more divergent sequence exploration beyond that limited to point mutations. We discuss how this approach may provide insights into the mechanism of enzyme evolution and function.

  15. Completion Rates and Accuracy of Performance Under Fixed and Variable Token Exchange Periods.

    ERIC Educational Resources Information Center

    McLaughlin, T. F.; Malaby, J. E.

    This research investigated the effects of employing fixed, variable, and extended token exchange periods for back-ups on the completion and accuracy of daily assignments for a total fifth and sixth-grade class. The results indicated that, in general, a higher percentage of assignments was completed when the number of days between point exchanges…

  16. Testing of a Loop Heat Pipe Subjective to Variable Accelerations. Part 1; Start-up

    NASA Technical Reports Server (NTRS)

    Ku, Jentung; Rogers, Paul; Hoff, Craig

    2000-01-01

    The effect of accelerating forces on the performance of loop heat pipes (LHP) is of interest and importance to terrestrial and space applications. They are being considered for cooling of military combat vehicles and for spinning spacecraft. In order to investigate the effect of an accelerating force on LHP operation, a miniature LHP was installed on a spin table. Variable accelerating forces were imposed on the LHP by spinning the table at different angular speeds. Several patterns of accelerating forces were applied, i.e. continuous spin at different speeds and periodic spin at different speeds and frequencies. The resulting accelerations ranged from 1.17 g's to 4.7 g's. This paper presents the first part of the experimental study, i.e. the effects of a centrifugal force on the LHP start-up. Tests were conducted by varying the heat load to the evaporator, sink temperature, magnitude and frequency of centrifugal force, and LHP orientation relative to the direction of the accelerating force. The accelerating force seems to have little effect on the loop start-up in terms of temperature overshoot and superheat at boiling incipience. Changes in these parameters seem to be stochastic with or without centrifugal accelerating forces. The LHP started successfully in all tests.

  17. TEMPORAL VARIABILITY OF INTERSTELLAR Na I ABSORPTION TOWARD THE MONOCEROS LOOP

    SciTech Connect

    Dirks, Cody; Meyer, David M. E-mail: davemeyer@northwestern.edu

    2016-03-01

    We report the first evidence of temporal variability in the interstellar Na i absorption toward HD 47240, which lies behind the Monoceros Loop supernova remnant (SNR). Analysis of multi-epoch Kitt Peak coudé feed spectra from this sight line taken over an eight-year period reveals significant variation in both the observed column density and the central velocities of the high-velocity gas components in these spectra. Given the ∼1.3 mas yr{sup −1} proper motion of HD 47240 and an SNR distance of 1.6 kpc, this variation would imply ∼10 au fluctuations within the SNR shell. Similar variations have been previously reported in the Vela SNR, suggesting a connection between the expanding SNR gas and the observed variations. We speculate on the potential nature of the observed variations toward HD 47240 in the context of the expanding remnant gas interacting with the ambient interstellar medium.

  18. Loop Current variability due to wind stress and reduced sea level during the Last Glacial Maximum

    NASA Astrophysics Data System (ADS)

    Mildner, T. C.; Eden, C.; Nuernberg, D.; Schoenfeld, J.

    2011-12-01

    One of the most prominent features of the circulation in the Gulf of Mexico is the Loop Current (LC). It is of special interest as it influences not only the climate in the Gulf of Mexico. Although causation is not well understood yet, dynamical relationships between LC retraction and extension, seasonal migrations of the Intertropical Convergence Zone (ITCZ) and the related wind stress curl over the subtropical North Atlantic, and changes in the thermohaline circulation are indicated by model simulations. A characteristic feature of the LC is the shedding of anticyclonic eddies. These eddies can have depth signatures of up to 1000 m and are of special interest as they supply heat and moisture into the western and northern Gulf. The eddies are generated aperiodically every 3 to 21 months, with an average shedding time of 9.5 months. Eddy shedding appears to be related to a suite of oceanographic forcing fields such as the Yucatan Channel throughflow, the Florida Current and North Brazil Current variability, as well as synoptic meteorological forcing variability. By combining state-of-the-art paleoceanographic and meso-scale eddy-resolving numerical modeling techniques, we examined the Loop Current dynamics and hydrographic changes in the Gulf going back in time up to ~21,000 years. To assess the impact of Last Glacial Maximum (LGM) wind stress and reduced sea level we have re-configured an existing hierarchy of models of the North Atlantic Ocean (FLAME) with a horizontal grid resolution of ca. 30 km (wind stress was taken from the PMIP-II database). The sea level was lowered compared to the CONTROL run by 110 m and 67 m. These sea level changes have been chosen according to the cold-deglacial periods Heinrich I and Younger Dryas. The result of our model simulations is a continuous increase in eddy shedding from the LGM to the Holocene. This increase is predominantly controlled by the continuous deglacial sea level rise. Changes in wind stress curl related to the

  19. Testing of a Loop Heat Pipe Subjective to Variable Accelerations. Part 2; Temperature Stability

    NASA Technical Reports Server (NTRS)

    Ku, Jentung; Ottenstein, Laura; Kaya, Taril; Rogers, Paul; Hoff, Craig

    2000-01-01

    The effect of accelerating forces on the performance of loop heat pipes (LHP) is of interest and importance to terrestrial and space applications. LHP's are being considered for cooling of military combat vehicles and for spinning spacecraft. In order to investigate the effect of an accelerating force on LHP operation, a miniature LHP was installed on a spin table. Variable accelerating forces were imposed on the LHP by spinning the table at different angular speeds. Several patterns of accelerating forces were applied, i.e. continuous spin at different speeds and periodic spin at different speeds and frequencies. The resulting accelerations ranged from 1.17 g's to 4.7 g's. This paper presents the second part of the experimental study, i.e. the effect of an accelerating force on the LHP operating temperature. It has been known that in stationary tests the LHP operating temperature is a function of the evaporator power and the condenser sink temperature when the compensation temperature is not actively controlled. Results of this test program indicate that any change in the accelerating force will result in a chance in the LHP operating temperature through its influence on the fluid distribution in the evaporator, condenser and compensation chamber. However, the effect is not universal, rather it is a function of other test conditions. A steady, constant acceleration may result in an increase or decrease of the operating temperature, while a periodic spin will lead to a quasi-steady operating temperature over a sufficient time interval. In addition, an accelerating force may lead to temperature hysteresis and changes in the temperature oscillation. In spite of all these effects, the LHP continued to operate without any problems in all tests.

  20. 4D Hybrid Ensemble-Variational Data Assimilation for the NCEP GFS: Outer Loops and Variable Transforms

    NASA Astrophysics Data System (ADS)

    Kleist, D. T.; Ide, K.; Mahajan, R.; Thomas, C.

    2014-12-01

    The use of hybrid error covariance models has become quite popular for numerical weather prediction (NWP). One such method for incorporating localized covariances from an ensemble within the variational framework utilizes an augmented control variable (EnVar), and has been implemented in the operational NCEP data assimilation system (GSI). By taking the existing 3D EnVar algorithm in GSI and allowing for four-dimensional ensemble perturbations, coupled with the 4DVAR infrastructure already in place, a 4D EnVar capability has been developed. The 4D EnVar algorithm has a few attractive qualities relative to 4DVAR, including the lack of need for tangent-linear and adjoint model as well as reduced computational cost. Preliminary results using real observations have been encouraging, showing forecast improvements nearly as large as were found in moving from 3DVAR to hybrid 3D EnVar. 4D EnVar is the method of choice for the next generation assimilation system for use with the operational NCEP global model, the global forecast system (GFS). The use of an outer-loop has long been the method of choice for 4DVar data assimilation to help address nonlinearity. An outer loop involves the re-running of the (deterministic) background forecast from the updated initial condition at the beginning of the assimilation window, and proceeding with another inner loop minimization. Within 4D EnVar, a similar procedure can be adopted since the solver evaluates a 4D analysis increment throughout the window, consistent with the valid times of the 4D ensemble perturbations. In this procedure, the ensemble perturbations are kept fixed and centered about the updated background state. This is analogous to the quasi-outer loop idea developed for the EnKF. Here, we present results for both toy model and real NWP systems demonstrating the impact from incorporating outer loops to address nonlinearity within the 4D EnVar context. The appropriate amplitudes for observation and background error

  1. The complete one-loop BMN S-matrix in AdS 3 × S 3 × T 4

    NASA Astrophysics Data System (ADS)

    Sundin, Per; Wulff, Linus

    2016-06-01

    We compute the full one-loop 2-particle S-matrix for excitations of the type IIB AdS 3 × S 3 × T 4 BMN string. The S-matrix is found to respect the expected symmetries and the phases are consistent with the crossing equations. By analyzing how the relevant integrals scale with the IR regulator we show that scattering of massless bosons is trivial at two loops. Based on our results we argue that the additional su(2) S-matrix appearing in the massless sector in the exact solution should trivialize.

  2. Form factors and complete spectrum of XXX antiperiodic higher spin chains by quantum separation of variables

    SciTech Connect

    Niccoli, G.

    2013-05-15

    The antiperiodic transfer matrices associated to higher spin representations of the rational 6-vertex Yang-Baxter algebra are analyzed by generalizing the approach introduced recently in the framework of Sklyanin's quantum separation of variables (SOV) for cyclic representations, spin-1/2 highest weight representations, and also for spin-1/2 representations of the 6-vertex reflection algebra. Such SOV approach allow us to derive exactly results which represent complicate tasks for more traditional methods based on Bethe ansatz and Baxter Q-operator. In particular, we both prove the completeness of the SOV characterization of the transfer matrix spectrum and its simplicity. Then, the derived characterization of local operators by Sklyanin's quantum separate variables and the expression of the scalar products of separate states by determinant formulae allow us to compute the form factors of the local spin operators by one determinant formulae similar to those of the scalar products.

  3. Completeness properties of R × R and real valued functions of two variables under lexicographic order

    NASA Astrophysics Data System (ADS)

    Endang Cahya M., A.

    2016-02-01

    The order in R × R which is commonly used is a partial order. In this article is discussed a different concept of order which gives a total order/lexicographic order for R × R. With respect to this order, we define a new concept of inequalities, Archimedean property and completeness in R × R. We also define a concept of monotonicity of real function of several variables and a number of its basic properties. The results will give fundamental aspects to define different concepts of multivariable calculus.

  4. Note: Phase-locked loop with a voltage controlled oscillator based on a liquid crystal cell as variable capacitance.

    PubMed

    Marcos, Carlos; Sánchez-Pena, José M; Torres, Juan C; Pérez, Isabel; Urruchi, Virginia

    2011-12-01

    A phase-locked loop is demonstrated using a twisted-nematic liquid crystal cell as a capacitance that can be varied as a function of applied voltage. The system is formed by a phase detector, a low-pass filter, as well as a voltage controlled oscillator including such variable capacitance. A theoretical study is proposed and experimentally validated. Capture and locked ranges of hundreds of kHz have been obtained for the configuration used in this circuit. An application as frequency demodulator using a practical implementation of this circuit has been demonstrated.

  5. Variable frequency pulsed phase-locked loop method for measuring material nonlinearity

    NASA Technical Reports Server (NTRS)

    Yost, William T.; Cantrell, John H.

    1992-01-01

    The design of a pressure vessel with an isothermal volume to measure changes in the natural velocities of material continuously over a wide temperature range is reported. Highly sensitive pulsed phase-locked loop technology is used to measure the natural velocity of fatigued aluminum 2024-T4 as a function of pressure at different temperatures. Second derivative variations with respect to pressure and temperature are found to exhibit order-of-magnitude changes at a gauge pressure near 950 kPa at room temperature. This indicates a significant change in certain combinations of second-order and higher-order elastic constants at relatively low pressures. Fractional frequency change as a function of applied pressure for aluminum 2024-T4 with fatigue damage is illustrated.

  6. Vaccine focusing to cross-subtype HIV-1 gp120 variable loop epitopes.

    PubMed

    Cardozo, Timothy; Wang, Shixia; Jiang, Xunqing; Kong, Xiang-Peng; Hioe, Catarina; Krachmarov, Chavdar

    2014-09-03

    We designed synthetic, epitope-focused immunogens that preferentially display individual neutralization epitopes targeted by cross-subtype anti-HIV V3 loop neutralizing monoclonal antibodies (mAbs). Vaccination of rabbits with these immunogens resulted in the elicitation of distinct polyclonal serum Abs that exhibit cross-subtype neutralization specificities mimicking the mAbs that guided the design. Our results prove the principle that a predictable range of epitope-specific polyclonal cross-subtype HIV-1 neutralizing Abs can be intentionally elicited in mammals by vaccination. The precise boundaries of the epitopes and conformational flexibility in the presentation of the epitopes in the immunogen appeared to be important for successful elicitation. This work may serve as a starting point for translating the activities of human broadly neutralizing anti-HIV-1 monoclonal antibodies (bNAbs) into matched immunogens that can contribute to an efficacious HIV-1 vaccine.

  7. Complete vertical M-H loop shift in La0.7Sr0.3MnO3/SrRuO3 thin film heterostructures

    NASA Astrophysics Data System (ADS)

    Singamaneni, Srinivasa Rao; Fan, Wu; Prater, J. T.; Narayan, J.

    2015-05-01

    In the current work, we have epitaxially integrated La0.7Sr0.3MnO3/SrRuO3 (LSMO/SRO) BLs with the technologically important substrate Si (100) using pulsed laser deposition. Interestingly, at 4 K, under the magnetic field sweep of ±1500 Oe, a complete vertical M-H loop shift is observed in the sample prepared with 180 nm SRO thickness, which is unusual. This vertical shift persists even up to a field sweep range of ±6000 Oe, at which point the shift disappears and a symmetrical hysteresis loop centered at the origin is observed. In contrast, at the same temperature, under the same field sweep range, we observe a normal M-H loop (no or little vertical shift) from the sample with 45 nm SRO thickness. In both the cases, the LSMO thickness was held constant at ˜100 nm. It appears that SRO moment is frozen in place in the latter case, providing a clear demonstration of the effect that biasing layer (SRO) thickness can have on the magnetic characteristics of bilayer films. We attribute this vertical shift to the strong interplay between the uniaxial magnetocrystalline anisotropy and microscopic interface domain structure.

  8. The genetic diversity of chicken breeds from Jiangxi, assessed with BCDO2 and the complete mitochondrial DNA D-loop region

    PubMed Central

    Tang, Xiu-jun; Fan, Yan-feng; Lu, Jun-xian; Huang, Sheng-hai; Tang, Meng-jun

    2017-01-01

    The Jiangxi Province of China has numerous native domestic chicken breeds, including some black skin breeds. The genetic diversity of Jiangxi native chickens is largely unknown, and specifically, the genetic contribution of the grey junglefowl to black skin chickens is not well understood. To address these questions, the complete D-loop region of the mitochondrial DNA (mtDNA) and beta-carotene dioxygenase 2(BCDO2)gene was sequenced in a total of 209 chickens representing seven Jiangxi native breeds. Thirty-one polymorphic sites were identified across the complete mtDNA D-loop region sequence. Twenty-three haplotypes were observed in the seven breeds, which belonged to four distinct mitochondrial clades (A, B, C and E). Clade A and B were dominant in the chickens with a frequency of approximately 67.9%. There were five SNPs that defined two haplotypes, W and Y in BCDO2. Four breeds had one haplotype and three breeds had two. We conclude that Jiangxi native chicken breeds have relatively low genetic diversity and likely share four common maternal lineages from two different maternal ancestors of junglefowl. Furthermore, some Jiangxi chicken populations may have been mixed with chickens with exotic lineage. Further research should be established to protect these domestic chicken resources. PMID:28257510

  9. Complete amino acid sequence of an acidic, cardiotoxic phospholipase A2 from the venom of Ophiophagus hannah (King Cobra): a novel cobra venom enzyme with "pancreatic loop".

    PubMed

    Huang, M Z; Gopalakrishnakone, P; Chung, M C; Kini, R M

    1997-02-15

    A phospholipase A2 (OHV A-PLA2) from the venom of Ophiophagus hannah (King cobra) is an acidic protein exhibiting cardiotoxicity, myotoxicity, and antiplatelet activity. The complete amino acid sequence of OHV A-PLA2 has been determined using a combination of Edman degradation and mass spectrometric techniques. OHV A-PLA2 is composed of a single chain of 124 amino acid residues with 14 cysteines and a calculated molecular weight of 13719 Da. It contains the loop of residues (62-66) found in pancreatic PLA2s and hence belongs to class IB enzymes. This pancreatic loop is between two proline residues (Pro 59 and Pro 68) and contains several hydrophilic amino acids (Ser and Asp). This region has high degree of conformational flexibility and is on the surface of the molecule, and hence it may be a potential protein-protein interaction site. A relatively low sequence homology is found between OHV A-PLA2 and other known cardiotoxic PLA2s, and hence a contiguous segment could not be identified as a site responsible for the cardiotoxic activity.

  10. Examining the Relationship between Immediate Serial Recall and Immediate Free Recall: Common Effects of Phonological Loop Variables but Only Limited Evidence for the Phonological Loop

    ERIC Educational Resources Information Center

    Spurgeon, Jessica; Ward, Geoff; Matthews, William J.

    2014-01-01

    We examined the contribution of the phonological loop to immediate free recall (IFR) and immediate serial recall (ISR) of lists of between one and 15 words. Following Baddeley (1986, 2000, 2007, 2012), we assumed that visual words could be recoded into the phonological store when presented silently but that recoding would be prevented by…

  11. The mitochondrial genome of Pocillopora (Cnidaria: Scleractinia) contains two variable regions: the putative D-loop and a novel ORF of unknown function.

    PubMed

    Flot, Jean-François; Tillier, Simon

    2007-10-15

    The complete mitochondrial genomes of two individuals attributed to different morphospecies of the scleractinian coral genus Pocillopora have been sequenced. Both genomes, respectively 17,415 and 17,422 nt long, share the presence of a previously undescribed ORF encoding a putative protein made up of 302 amino acids and of unknown function. Surprisingly, this ORF turns out to be the second most variable region of the mitochondrial genome (1% nucleotide sequence difference between the two individuals) after the putative control region (1.5% sequence difference). Except for the presence of this ORF and for the location of the putative control region, the mitochondrial genome of Pocillopora is organized in a fashion similar to the other scleractinian coral genomes published to date. For the first time in a cnidarian, a putative second origin of replication is described based on its secondary structure similar to the stem-loop structure of O(L), the origin of L-strand replication in vertebrates.

  12. Examining the relationship between immediate serial recall and immediate free recall: common effects of phonological loop variables but only limited evidence for the phonological loop.

    PubMed

    Spurgeon, Jessica; Ward, Geoff; Matthews, William J

    2014-07-01

    We examined the contribution of the phonological loop to immediate free recall (IFR) and immediate serial recall (ISR) of lists of between one and 15 words. Following Baddeley (1986, 2000, 2007, 2012), we assumed that visual words could be recoded into the phonological store when presented silently but that recoding would be prevented by concurrent articulation (CA; Experiment 1). We further assumed that the use of the phonological loop would be evidenced by greater serial recall for lists of phonologically dissimilar words relative to lists of phonologically similar words (Experiments 2A and 2B). We found that in both tasks, (a) CA reduced recall; (b) participants recalled short lists from the start of the list, leading to enhanced forward-ordered recall; (c) participants were increasingly likely to recall longer lists from the end of the list, leading to extended recency effects; (d) there were significant phonological similarity effects in ISR and IFR when both were analyzed using serial recall scoring; (e) these were reduced by free recall scoring and eliminated by CA; and (f) CA but not phonological similarity affected the tendency to initiate recall with the first list item. We conclude that similar mechanisms underpin ISR and IFR. Critically, the phonological loop is not strictly necessary for the forward-ordered recall of short lists on both tasks but may augment recall by increasing the accessibility of the list items (relative to CA), and in so doing, the order of later items is preserved better in phonologically dissimilar than in phonologically similar lists.

  13. The V4 and V5 Variable Loops of HIV-1 Envelope Glycoprotein Are Tolerant to Insertion of Green Fluorescent Protein and Are Useful Targets for Labeling.

    PubMed

    Nakane, Shuhei; Iwamoto, Aikichi; Matsuda, Zene

    2015-06-12

    The mature human immunodeficiency virus type 1 (HIV-1) envelope glycoprotein (Env) comprises the non-covalently associated gp120 and gp41 subunits generated from the gp160 precursor. Recent structural analyses have provided quaternary structural models for gp120/gp41 trimers, including the variable loops (V1-V5) of gp120. In these models, the V3 loop is located under V1/V2 at the apical center of the Env trimer, and the V4 and V5 loops project outward from the trimeric protomers. In addition, the V4 and V5 loops are predicted to have less movement upon receptor binding during membrane fusion events. We performed insertional mutagenesis using a GFP variant, GFPOPT, placed into the variable loops of HXB2 gp120. This allowed us to evaluate the current structural models and to simultaneously generate a GFP-tagged HIV-1 Env, which was useful for image analyses. All GFP-inserted mutants showed similar levels of whole-cell expression, although certain mutants, particularly V3 mutants, showed lower levels of cell surface expression. Functional evaluation of their fusogenicities in cell-cell and virus-like particle-cell fusion assays revealed that V3 was the most sensitive to the insertion and that the V1/V2 loops were less sensitive than V3. The V4 and V5 loops were the most tolerant to insertion, and certain tag proteins other than GFPOPT could also be inserted without functional consequences. Our results support the current structural models and provide a GFPOPT-tagged Env construct for imaging studies.

  14. Genetic variability between complete mitochondrion genomes of the sablefish, Anoplopoma fimbria (Pallas, 1814).

    PubMed

    Galván-Tirado, Carolina; Del Río-Portilla, Miguel Angel; Delgado-Vega, Rigoberto; García-De León, Francisco J

    2016-07-01

    The complete mitochondrial genome of the sablefish, Anoplopoma fimbria (Genbank accession KP777542) is 16,507 bp in size and contains the typical 37 genes (13 protein-coding, 2 ribosomal RNA, and 22 transfer RNA) found in teleosts mitogenomes. The genome varies in 118 positions with respect to another mitogenome sablefish specimen.

  15. Replication and neutralization of human immunodeficiency virus type 1 lacking the V1 and V2 variable loops of the gp120 envelope glycoprotein.

    PubMed Central

    Cao, J; Sullivan, N; Desjardin, E; Parolin, C; Robinson, J; Wyatt, R; Sodroski, J

    1997-01-01

    A human immunodeficiency virus type 1 (HIV-1) mutant lacking the V1 and V2 variable loops in the gp120 exterior envelope glycoprotein replicated in Jurkat lymphocytes with only modest delays compared with the wild-type virus. Revertants that replicated with wild-type efficiency rapidly emerged and contained only a few amino acid changes in the envelope glycoproteins compared with the parent virus. Both the parent and revertant viruses exhibited increased sensitivity to neutralization by antibodies directed against the V3 loop or a CD4-induced epitope on gp120 but not by soluble CD4 or an antibody against the CD4 binding site. This result demonstrates the role of the gp120 V1 and V2 loops in protecting HIV-1 from some subsets of neutralizing antibodies. PMID:9371651

  16. Variable Temperature, Intensity Calibrated, Complete Submillimeter Spectra and Analysis for Astrophysical Assignment

    NASA Astrophysics Data System (ADS)

    Fortman, Sarah M.

    Traditional spectroscopic approaches which relied on quantum mechanical assignment have left astrophysical catalogs incomplete with regards to the perturbed excited vibrational/torsional states of several astrophysically common molecular species. The result is that many of the unidentified features in astrophysical spectra are due to already identified species in an excited state. The confusion of lines due to target species and lines due to molecular 'weeds', hinders the astronomers' ability to identify new molecules in astrophysical spectra. With the advent of powerful new telescopes this problem has been further exacerbated. This thesis describes a new approach for analyzing intensity calibrated laboratory spectra taken at many different temperatures. By analyzing these spectra together, it is possible to derive the lower state energy and transition strength for every spectral line without quantum mechanical assignment. These derived parameters can then be used to predict a complete spectrum, including the difficult to assign excited states, at astrophysically relevant temperatures. Unlike the astrophysical catalogs this approach is not limited to spectral lines. By using fitting parameters, every frequency point of laboratory data can be modeled and the entire spectral range can be predicted at an arbitrary temperature. This approach was developed, tested and refined while studying eight astrophysical 'weeds' in two frequency regions. In ethyl cyanide, vinyl cyanide and methanol, the three molecules for which rigorous analysis was completed, the lower state energies and transition strengths were determined for over 8200 currently uncataloged lines. An additional five molecules in the 210-270 GHz region have had preliminary analyses completed. Astrophysical data was obtained and compared to the complete spectra predicted from this analysis. The results yielded excellent matches for methyl cyanide, ethyl cyanide and vinyl cyanide including isotopologues and

  17. Structure and variability of the Yucatan and loop currents along the slope and shelf break of the Yucatan channel and Campeche bank

    NASA Astrophysics Data System (ADS)

    Sheinbaum, Julio; Athié, Gabriela; Candela, Julio; Ochoa, José; Romero-Arteaga, Angélica

    2016-12-01

    Three years (2008-2011) of direct current measurements from a mooring array deployed at the western Yucatan Channel (defined west of 85.6°W) and along the eastern Campeche Bank captured the main characteristics of the Yucatan and Loop Currents and the eddies associated with them. The array was deployed to provide upstream conditions in support of the Loop Current Dynamics Experiment. A substantial portion (60-80%) of the variance at the mooring sections is related to horizontal shifts of the currents due to meanders and eddies. Time-frequency analysis indicates that the velocity time-series are "event dominated", with higher variability at low-frequencies (40-100 days or longer periods) but with a substantial contribution at higher frequencies (5-25 days periods) particularly strong from October to March. The vertical structure and time evolution of the eddy kinetic energy in a developing Campeche Bank cyclone suggest baroclinic instability dynamics are relevant for its development. Four Loop Current eddies (Cameron, Darwin, Ekman and Franklin) separated during 2008-2011. Ekman and Franklin were particularly dominated by a cyclone associated with a meander trough of the southward flowing branch of the Loop Current (Donohue et al., 2016a,b) and weaker Campeche Bank cyclones. For Cameron and Darwin, Campeche Bank cyclonic anomalies appear to be nearly as strong as the ones coming from the eastern side of the Loop Current. Eastward shifts of the Yucatan and Loop Currents observed over the sections appear to be linked to vorticity perturbations propagating from the Caribbean and precede several eddy detachments; their significance for the generation of Campeche Bank cyclones and eddy shedding remains to be determined. Time-series of Yucatan Current transport, vorticity fluctuations and Loop Current northward extension during the 3 deployment periods only depict positive correlation in two of them. Given the wide spectrum of variability, much more data are required to

  18. Numerical scheme to complete a compressible gas flow in variable porosity media

    NASA Astrophysics Data System (ADS)

    Rochette, D.; Clain, S.; Buffard, T.

    2005-05-01

    We present an approximate Riemann solver coupled with a finite volume method to compute non conservative Euler equations in variable porosity media using ideal gas state law. The non conservative term is numerically taken into account from an original idea of LeRoux (1998) but here Riemann problems at each interface of the mesh are linearized using a VFRoe approach. The main goal is the resolution of the non conservative system even if the porosity is discontinuous. Stationary solutions are determined with continuous and discontinuous porosity in order to test the numerical scheme and computations of gas shock subsonic wave moving in a non continuous porosity medium are presented.

  19. Involvement of the V1/V2 variable loop structure in the exposure of human immunodeficiency virus type 1 gp120 epitopes induced by receptor binding.

    PubMed Central

    Wyatt, R; Moore, J; Accola, M; Desjardin, E; Robinson, J; Sodroski, J

    1995-01-01

    The binding of human immunodeficiency virus type 1 (HIV-1) to the cellular receptor CD4 has been suggested to induce conformational changes in the viral envelope glycoproteins that promote virus entry. Conserved, discontinuous epitopes on the HIV-1 gp120 glycoprotein recognized by the 17b, 48d, and A32 antibodies are preferentially exposed upon the binding of soluble CD4 (sCD4). The binding of the 17b and 48d antibodies to the gp120 glycoprotein can also be enhanced by the binding of the A32 antibody. Here we constructed HIV-1 gp120 mutants in which the variable segments of the V1/V2 and V3 structures were deleted, individually or in combination, while the 17b, 48d, and A32 epitopes were retained. The effects of the variable loop deletions on the function of the HIV-1 envelope glycoproteins and on the exposure of epitopes induced by sCD4 or A32 binding to the monomeric gp120 glycoprotein were examined. The variable-loop-deleted envelope glycoproteins were able to mediate virus entry, albeit at lower efficiencies than those of the wild-type glycoproteins. Thus, the V1/V2 and V3 variable sequences contribute to the efficiency of HIV-1 entry but are not absolutely required for the process. Neither the V1/V2 nor V3 loops were necessary for the increase in exposure of the 17b/48d epitopes induced by binding of the A32 monoclonal antibody. By contrast, induction of the 17b, 48d, and A32 epitopes by sCD4 binding apparently involves a movement of the V1/V2 loops, which in the absence of CD4 partially mask these epitopes on the native gp120 monomer. The results obtained with a mutant glycoprotein containing a deletion of the V1 loop alone indicated that the contribution of the V2 loop to these phenomena was more significant than that of the V1 sequences. These results suggest that the V1/V2 loops, which have been previously implicated in CD4-modulated, postattachment steps in HIV-1 entry, contribute to CD4-induced gp120 conformational changes detected by the 17b, 48d, and A

  20. Adenoviral vectors elicit humoral immunity against variable loop 2 of clade C HIV-1 gp120 via “Antigen Capsid-Incorporation” strategy

    PubMed Central

    Gu, Linlin; Krendelchtchikova, Valentina; Krendelchtchikov, Alexandre; Farrow, Anitra L.; Derdeyn, Cynthia A.; Matthews, Qiana L.

    2016-01-01

    Adenoviral (Ad) vectors in combination with the “Antigen Capsid-Incorporation” strategy have been applied in developing HIV-1 vaccines, due to the vectors’ abilities in incorporating and inducing immunity of capsid-incorporated antigens. Variable loop 2 (V2)-specific antibodies were suggested in the RV144 trial to correlate with reduced HIV-1 acquisition, which highlights the importance of developing novel HIV-1 vaccines by targeting the V2 loop. Therefore, the V2 loop of HIV-1 has been incorporated into the Ad capsid protein. We generated adenovirus serotype 5 (Ad5) vectors displaying variable loop 2 (V2) of HIV-1 gp120, with the “Antigen Capsid-Incorporation” strategy. To assess the incorporation capabilities on hexon hypervariable region1 (HVR1) and protein IX (pIX), 20aa or full length (43aa) of V2 and V1V2 (67aa) were incorporated, respectively. Immunizations with the recombinant vectors significantly generated antibodies against both linear and discontinuous V2 epitopes. The immunizations generated durable humoral immunity against V2. This study will lead to more stringent development of various serotypes of adenovirus-vectored V2 vaccine candidates, based on breakthroughs regarding the immunogenicity of V2. PMID:26499044

  1. Complete one-loop MSSM predictions for B{sup 0}{yields}l{sup +}l{sup '-} at the Tevatron and LHC

    SciTech Connect

    Dedes, Athanasios; Rosiek, Janusz; Tanedo, Philip

    2009-03-01

    During the last few years the Tevatron has dramatically improved the bounds on rare B-meson decays into two leptons. In the case of B{sub s}{sup 0}{yields}{mu}{sup +}{mu}{sup -}, the current bound is only 10 times greater than the standard model expectation. Sensitivity to this decay is one of the benchmark goals for LHCb performance and physics. The Higgs penguin dominates this rate in the region of large tan{beta} of the minimal supersymmetric standard model. This is not necessarily the case in the region of low tan{beta}, since box and Z-penguin diagrams may contribute at a comparable rate. In this article, we compute the complete one-loop minimal supersymmetric standard model contribution to B{sub s,d}{sup 0}{yields}l{sup +}l{sup '-} for l, l{sup '}=e, {mu}. We study the predictions for general values of tan{beta} with arbitrary flavor mixing parameters. We discuss the possibility of both enhancing and suppressing the branching ratios relative to their standard model expectations. In particular, we find that there are 'cancellation regions' in parameter space where the branching ratio is suppressed well below the standard model expectation, making it effectively invisible to the LHC.

  2. Complete sequence and variability of a new subgroup B nepovirus infecting potato in central Peru.

    PubMed

    De Souza, Joao; Müller, Giovanna; Perez, Wilmer; Cuellar, Wilmer; Kreuze, Jan

    2017-03-01

    The complete bipartite genome (RNA1 and RNA2) of a new nepovirus infecting potato was obtained using small RNA sequencing and assembly complemented by Sanger sequencing. Each RNA encodes a single polyprotein, flanked by 5' and 3' untranslate regions (UTR) and followed by a poly (A) tail. The putative polyproteins encoded by RNA1 and RNA2 had sets of motifs which are characteristic of viruses in the genus Nepovirus. Sequence comparisons using the Pro-Pol region and the coat protein, including phylogenetic analysis of these regions, showed closest relationships with nepoviruses. The data obtained support the taxonomical status of this new virus (putative named Potato virus B, PVB) as a member of the genus Nepovirus, subgroup B.

  3. A complete record of Holocene glacier variability at Austre Okstindbreen, northern Norway: an integrated approach

    NASA Astrophysics Data System (ADS)

    Bakke, Jostein; Dahl, Svein Olaf; Paasche, Øyvind; Riis Simonsen, Joachim; Kvisvik, Bjørn; Bakke, Kristina; Nesje, Atle

    2010-05-01

    Arctic glaciers are currently undergoing major changes, but accurate knowledge about how they varied during the entire Holocene is still scarce. Here we present a new complete glacier record from Austre Okstindbreen in Nordland, northern Norway. This reconstruction is based on a number of short and long cores retrieved from several downstream basins, which have been analyzed by a suite of methods including geochemical elements (XRF), rock magnetic properties, dry bulk density (DBD) and Loss-on-ignition (LOI). Lake sediment distribution was surveyed and mapped prior to coring by the use of ground penetrating radar (GPR). Independently lichen-dated marginal moraines and historical information about the glacier frontal positions from old photographs and maps have made it possible to link the moraine sequence to the 210Pb dated lake sediment chronology. This integrated approach reveals that Austre Okstindbreen is the first known glacier in Scandinavia to possibly have survived the "Holocene Thermal Optimum". It also brackets the four largest glacier advances to c 7400-7000, 1400-1200, 900-700 and 300-150 years before AD 2000 (b2k). In contrast to most reconstructed glaciers in Scandinavia, the largest glacier advance was not associated with the "Little Ice Age", but rather to an earlier period centred at 1300 b2k. Both the moraine chronology and the lacustrine records document this Neoglacial advance. Compared to other glacier reconstructions from the Northern Hemisphere, we identify near-synchronous glacier advances occurring roughly at 4000 b2k; 2700 b2k; 1300 b2k and during the "Little Ice Age". These correlative advances across the Northern Hemisphere suggest that these observed centennial-scale events are a shared feature regardless of the large geographical distances separating them. Some minor discrepancies between different geographical areas may be caused by lack of precise dating, but local climatic conditions may play a role as well.

  4. The Complete Nucleotide Sequence and Biotype Variability of Papaya leaf distortion mosaic virus.

    PubMed

    Maoka, Tetsuo; Hataya, Tatsuji

    2005-02-01

    ABSTRACT The complete nucleotide sequence of the genome of Papaya leaf distortion mosaic virus (PLDMV) was determined. The viral RNA genome of strain LDM (leaf distortion mosaic) comprised 10,153 nucleotides, excluding the poly(A) tail, and contained one long open reading frame encoding a polyprotein of 3,269 amino acids (molecular weight 373,347). The polyprotein contained nine putative proteolytic cleavage sites and some motifs conserved in other potyviral polyproteins with 44 to 50% identities, indicating that PLDMV is a distinct species in the genus Potyvirus. Like the W biotype of Papaya ringspot virus (PRSV), the non-papaya-infecting biotype of PLDMV (PLDMV-C) was found in plants of the family Cucurbitaceae. The coat protein (CP) sequence of PLDMV-C in naturally infected-Trichosanthes bracteata was compared with those of three strains of the P biotype (PLDMV-P), LDM and two additional strains M (mosaic) and YM (yellow mosaic), which are biologically different from each other. The CP sequences of three strains of PLDMV-P share high identities of 95 to 97%, while they share lower identities of 88 to 89% with that of PLDMV-C. Significant changes in hydrophobicity and a deletion of two amino acids at the N-terminal region of the CP of PLDMV-C were observed. The finding of two biotypes of PLDMV implies the possibility that the papaya-infecting biotype evolved from the cucurbitaceae-infecting potyvirus, as has been previously suggested for PRSV. In addition, a similar evolutionary event acquiring infectivity to papaya may arise frequently in viruses in the family Cucurbitaceae.

  5. Open spin chains with generic integrable boundaries: Baxter equation and Bethe ansatz completeness from separation of variables

    NASA Astrophysics Data System (ADS)

    Kitanine, N.; Maillet, J. M.; Niccoli, G.

    2014-05-01

    We solve the longstanding problem of defining a functional characterization of the spectrum of the transfer matrix associated with the most general spin-1/2 representations of the six-vertex reflection algebra for general inhomogeneous chains. The corresponding homogeneous limit reproduces the spectrum of the Hamiltonian of the spin-1/2 open XXZ and XXX quantum chains with the most general integrable boundaries. The spectrum is characterized by a second order finite difference functional equation of Baxter type with an inhomogeneous term which vanishes only for some special but yet interesting non-diagonal boundary conditions. This functional equation is shown to be equivalent to the known separation of variables (SOV) representation, hence proving that it defines a complete characterization of the transfer matrix spectrum. The polynomial form of the Q-function allows us to show that a finite system of generalized Bethe equations can also be used to describe the complete transfer matrix spectrum.

  6. Coupled dual loop absorption heat pump

    DOEpatents

    Sarkisian, Paul H.; Reimann, Robert C.; Biermann, Wendell J.

    1985-01-01

    A coupled dual loop absorption system which utilizes two separate complete loops. Each individual loop operates at three temperatures and two pressures. This low temperature loop absorber and condenser are thermally coupled to the high temperature loop evaporator, and the high temperature loop condenser and absorber are thermally coupled to the low temperature generator.

  7. Design of experiments with multiple independent variables: a resource management perspective on complete and reduced factorial designs.

    PubMed

    Collins, Linda M; Dziak, John J; Li, Runze

    2009-09-01

    An investigator who plans to conduct an experiment with multiple independent variables must decide whether to use a complete or reduced factorial design. This article advocates a resource management perspective on making this decision, in which the investigator seeks a strategic balance between service to scientific objectives and economy. Considerations in making design decisions include whether research questions are framed as main effects or simple effects; whether and which effects are aliased (confounded) in a particular design; the number of experimental conditions that must be implemented in a particular design and the number of experimental subjects the design requires to maintain the desired level of statistical power; and the costs associated with implementing experimental conditions and obtaining experimental subjects. In this article 4 design options are compared: complete factorial, individual experiments, single factor, and fractional factorial. Complete and fractional factorial designs and single-factor designs are generally more economical than conducting individual experiments on each factor. Although relatively unfamiliar to behavioral scientists, fractional factorial designs merit serious consideration because of their economy and versatility.

  8. Affirming Proposed Variable Relationship Patterns in a Conceptual Nursing Model by Converting Qualitative Data to Causal Loop Diagrams

    PubMed Central

    Browne, Jennifer A.

    2016-01-01

    Even with decades of use, there is minimal understanding about the impact that the use of Health Information Technology has on nursing work and workarounds. Reliance on quantitative methods has to some degree constrained our understanding by viewing phenomena from only one perspective. This multimethods research used qualitative data to develop causal loop diagrams and inform a Health Information Technology Workaround model. This approach can play an important role in generating an improved understanding of nursing clinical workflow and workarounds. This research strategy has not been identified in nursing literature to date, but perhaps will encourage future exploration and paradigm crossing. Investigating the use of causal loop diagrams and systems modelling in nursing can create an opportunity to enrich our insights and encourage scientific dialogue about the complexity of clinical workflow and the integration of Health Information Technology. PMID:28269931

  9. Regulative Loops, Step Loops and Task Loops

    ERIC Educational Resources Information Center

    VanLehn, Kurt

    2016-01-01

    This commentary suggests a generalization of the conception of the behavior of tutoring systems, which the target article characterized as having an outer loop that was executed once per task and an inner loop that was executed once per step of the task. A more general conception sees these two loops as instances of regulative loops, which…

  10. Multi-variable control of the GE T700 engine using the LQG/LTR design methodology. [Linear Quadratic Gaussian/Loop Transfer Recovery method

    NASA Technical Reports Server (NTRS)

    Pfeil, W. H.; Athans, M.; Spang, H. A., III

    1986-01-01

    The design of scalar and multi-variable feedback control systems for the GE T700 turboshaft engine coupled to a helicopter rotor system is examined. A series of linearized models are presented and analyzed. Robustness and performance specifications are posed in the frequency domain. The linear-quadratic-Gaussian with loop-transfer-recovery (LQG/LTR) methodology is used to obtain a sequence of three feedback designs. Even in the single-input/single-output case, comparison of the current control system with that derived from the LQG/LTR approach shows significant performance improvement. The multi-variable designs, evaluated using linear and nonlinear simulations, show even more potential for performance improvement.

  11. The Shark Strikes Twice: Hypervariable Loop 2 of Shark IgNAR Antibody Variable Domains and Its Potential to Function as an Autonomous Paratope.

    PubMed

    Zielonka, Stefan; Empting, Martin; Könning, Doreen; Grzeschik, Julius; Krah, Simon; Becker, Stefan; Dickgießer, Stephan; Kolmar, Harald

    2015-08-01

    In this present study, we engineered hypervariable loop 2 (HV2) of the IgNAR variable domain in a way that it solely facilitates antigen binding, potentially functioning as an autonomous paratope. For this, the surface-exposed loop corresponding to HV2 was diversified and antigen-specific variable domain of IgNAR antibody (vNAR) molecules were isolated by library screening using yeast surface display (YSD) as platform technology. An epithelial cell adhesion molecule (EpCAM)-specific vNAR was used as starting material, and nine residues in HV2 were randomized. Target-specific clones comprising a new HV2-mediated paratope were isolated against cluster of differentiation 3ε (CD3ε) and human Fcγ while retaining high affinity for EpCAM. Essentially, we demonstrate that a new paratope comprising moderate affinities against a given target molecule can be engineered into the vNAR scaffold that acts independent of the original antigen-binding site, composed of complementarity-determining region 3 (CDR3) and CDR1.

  12. Identification of New Regions in HIV-1 gp120 Variable 2 and 3 Loops that Bind to α4β7 Integrin Receptor

    PubMed Central

    Peachman, Kristina K.; Karasavvas, Nicos; Chenine, Agnes-Laurence; McLinden, Robert; Rerks-Ngarm, Supachai; Jaranit, Kaewkungwal; Nitayaphan, Sorachai; Pitisuttithum, Punnee; Tovanabutra, Sodsai; Zolla-Pazner, Susan; Michael, Nelson L.; Kim, Jerome H.; Alving, Carl R.; Rao, Mangala

    2015-01-01

    Background The gut mucosal homing integrin receptor α4β7 present on activated CD4+ T cells interacts with the HIV-1 gp120 second variable loop (V2). Case control analysis of the RV144 phase III vaccine trial demonstrated that plasma IgG binding antibodies specific to scaffolded proteins expressing the first and second variable regions (V1V2) of HIV envelope protein gp120 containing the α4β7 binding motif correlated inversely with risk of infection. Subsequently antibodies to the V3 region were also shown to correlate with protection. The integrin receptor α4β7 was shown to interact with the LDI/V motif on V2 loop but recent studies suggest that additional regions of V2 loop could interact with the α4β7. Thus, there may be several regions on the V2 and possibly V3 loops that may be involved in this binding. Using a cell line, that constitutively expressed α4β7 receptors but lacked CD4, we examined the contribution of V2 and V3 loops and the ability of V2 peptide-, V2 integrin-, V3-specific monoclonal antibodies (mAbs), and purified IgG from RV144 vaccinees to block the V2/V3-α4β7 interaction. Results We demonstrate that α4β7 on RPMI8866 cells bound specifically to its natural ligand mucosal addressin cell adhesion molecule-1 (MAdCAM-1) as well as to cyclic-V2 and cyclic-V3 peptides. This binding was inhibited by anti-α4β7-specific monoclonal antibody (mAb) ACT-1, mAbs specific to either V2 or V3 loops, and by purified primary virions or infectious molecular clones expressing envelopes from acute or chronic subtypes A, C, and CRF01_AE viruses. Plasma from HIV-1 infected Thai individuals as well as purified IgG from uninfected RV144 vaccinees inhibited (0–50%) the binding of V2 and V3 peptides to α4β7. Conclusion Our results indicate that in addition to the tripeptide LDI/V motif, other regions of the V2 and V3 loops of gp120 were involved in binding to α4β7 receptors and this interaction was blocked by anti-V2 peptide, anti-V2 integrin, and anti

  13. iHeartLift: a closed loop system with bio-feedback that uses music tempo variability to improve heart rate variability.

    PubMed

    Ho, Thomas C T; Chen, Xiang

    2011-01-01

    "Musica delenit bestiam feram" translates into "Music soothes the savage beast". There is a hidden truth in this ancient quip passed down from generations. Besides soothing the heart, it also incites the heart to a healthier level of heart rate variability (HRV). In this paper, an approach to use and test music and biofeedback to increase the heart rate variability for people facing daily stress is discussed. By determining the music tempo variability (MTV) of a piece of music and current heart rate variability, iHeartLift is able to compare the 2 trends and locate a musical piece that is suited to increase the user's heart rate variability to a healthier level. With biofeedback, the 2 trends are continuously compared in real-time and the musical piece is changed in accordance with the current comparisons. A study was conducted and it was generally found that HRV can be uplifted by music regardless of language and meaning of musical lyrics but with limitations to musical genre.

  14. The complete genome sequence of the Alphaentomopoxvirus Anomala cuprea entomopoxvirus, including its terminal hairpin loop sequences, suggests a potentially unique mode of apoptosis inhibition and mode of DNA replication.

    PubMed

    Mitsuhashi, Wataru; Miyamoto, Kazuhisa; Wada, Sanae

    2014-03-01

    Complete genome sequence of Anomala cuprea entomopoxvirus, which belongs to the genus Alphaentomopoxvirus, including its terminal hairpin loop sequences, is reported. This is the first genome sequence of Alphaentomopoxvirus reported, and hairpin loops in entomopoxviruses have not previously been sequenced. The genome is 245,717 bp, which is smaller than had previously been estimated for Alphaentomopoxvirus. The inverted terminal repeats are quite long, and experimental results suggest that one genome molecule has one type of hairpin at one end and another type at the other end. The genome contains unexpected ORFs, e.g., that for the ubiquitin-conjugating enzyme E2 of eukaryotes. The BIR and RING domains found in a single ORF for an inhibitor of apoptosis in baculoviruses and entomopoxviruses occurred in two different, widely separated ORFs. Furthermore, an ORF in the genome contains a serpin domain that was previously found in vertebrate poxviruses for apoptosis inhibition but not in insect viruses.

  15. Quantum theory of optical temporal phase and instantaneous frequency. II. Continuous-time limit and state-variable approach to phase-locked loop design

    SciTech Connect

    Tsang, Mankei; Shapiro, Jeffrey H.; Lloyd, Seth

    2009-05-15

    We consider the continuous-time version of our recently proposed quantum theory of optical temporal phase and instantaneous frequency [M. Tsang et al., Phys. Rev. A 78, 053820 (2008)]. Using a state-variable approach to estimation, we design homodyne phase-locked loops that can measure the temporal phase with quantum-limited accuracy. We show that postprocessing can further improve the estimation performance if delay is allowed in the estimation. We also investigate the fundamental uncertainties in the simultaneous estimation of harmonic-oscillator position and momentum via continuous optical phase measurements from the classical estimation theory perspective. In the case of delayed estimation, we find that the inferred uncertainty product can drop below that allowed by the Heisenberg uncertainty relation. Although this result seems counterintuitive, we argue that it does not violate any basic principle of quantum mechanics.

  16. Loop quantization

    SciTech Connect

    Nicolau, A.

    1988-10-01

    Loop unwinding is a known technique for reducing loop overhead, exposing parallelism, and increasing the efficiency of pipelining. Traditional loop unwinding is limited to the innermost loop in a group of nested loops and the amount of unwinding either is fixed or must be specified by the user, on a case by case basis. In this paper the authors present a general technique for automatically unwinding multiply nested loops, explain its advantages over other transformation techniques, and illustrate its practical effectiveness. Lopp Quantization could be beneficial by itself or coupled with other loop transformations.

  17. Bimodal loop-gap resonator

    NASA Astrophysics Data System (ADS)

    Piasecki, W.; Froncisz, W.; Hyde, James S.

    1996-05-01

    A bimodal loop-gap resonator for use in electron paramagnetic resonance (EPR) spectroscopy at S band is described. It consists of two identical one-loop-one-gap resonators in coaxial juxtaposition. In one mode, the currents in the two loops are parallel and in the other antiparallel. By introducing additional capacitors between the loops, the frequencies of the two modes can be made to coincide. Details are given concerning variable coupling to each mode, tuning of the resonant frequency of one mode to that of the other, and adjustment of the isolation between modes. An equivalent circuit is given and network analysis carried out both experimentally and theoretically. EPR applications are described including (a) probing of the field distributions with DPPH, (b) continuous wave (cw) EPR with a spin-label line sample, (c) cw electron-electron double resonance (ELDOR), (d) modulation of saturation, and (e) saturation-recovery (SR) EPR. Bloch induction experiments can be performed when the sample extends half way through the structure, but microwave signals induced by Mx and My components of magnetization cancel when it extends completely through. This latter situation is particularly favorable for SR, modulation of saturation, and ELDOR experiments, which depend on observing Mz indirectly using a second weak observing microwave source.

  18. Unliganded HIV-1 gp120 core structures assume the CD4-bound conformation with regulation by quaternary interactions and variable loops

    SciTech Connect

    Kwon, Young Do; Finzi, Andrés; Wu, Xueling; Dogo-Isonagie, Cajetan; Lee, Lawrence K.; Moore, Lucas R.; Schmidt, Stephen D.; Stuckey, Jonathan; Yang, Yongping; Zhou, Tongqing; Zhu, Jiang; Vicic, David A.; Debnath, Asim K.; Shapiro, Lawrence; Bewley, Carole A.; Mascola, John R.; Sodroski, Joseph G.; Kwong, Peter D.

    2013-03-04

    The HIV-1 envelope (Env) spike (gp120{sub 3}/gp41{sub 3}) undergoes considerable structural rearrangements to mediate virus entry into cells and to evade the host immune response. Engagement of CD4, the primary human receptor, fixes a particular conformation and primes Env for entry. The CD4-bound state, however, is prone to spontaneous inactivation and susceptible to antibody neutralization. How does unliganded HIV-1 maintain CD4-binding capacity and regulate transitions to the CD4-bound state? To define this mechanistically, we determined crystal structures of unliganded core gp120 from HIV-1 clades B, C, and E. Notably, all of these unliganded HIV-1 structures resembled the CD4-bound state. Conformational fixation with ligand selection and thermodynamic analysis of full-length and core gp120 interactions revealed that the tendency of HIV-1 gp120 to adopt the CD4-bound conformation was restrained by the V1/V2- and V3-variable loops. In parallel, we determined the structure of core gp120 in complex with the small molecule, NBD-556, which specifically recognizes the CD4-bound conformation of gp120. Neutralization by NBD-556 indicated that Env spikes on primary isolates rarely assume the CD4-bound conformation spontaneously, although they could do so when quaternary restraints were loosened. Together, the results suggest that the CD4-bound conformation represents a 'ground state' for the gp120 core, with variable loop and quaternary interactions restraining unliganded gp120 from 'snapping' into this conformation. A mechanism of control involving deformations in unliganded structure from a functionally critical state (e.g., the CD4-bound state) provides advantages in terms of HIV-1 Env structural diversity and resistance to antibodies and inhibitors, while maintaining elements essential for entry.

  19. Investigation of coal fueled chemical looping combustion using Fe3O4 as oxygen carrier: Influence of variables

    NASA Astrophysics Data System (ADS)

    Sun, Xiaoyan; Xiang, Wenguo; Wang, Sha; Tian, Wendong; Xu, Xiang; Xu, Yanji; Xiao, Yunhan

    2010-06-01

    Chemical-looping combustion (CLC) is a novel combustion technique with inherent CO2 separation. Magnetite (Fe3O4) was selected as the oxygen carrier. Shenhua coal (Inner Mongolia, China), straw coke and natural coke were used as fuels for this study. Influences of operation temperatures, coal to Fe3O4 mass ratios, and different kinds of fuels on the reduction characteristics of the oxygen carrier were investigated using an atmosphere thermogravimetric analyzer (TGA). Scanning electron microscopy (SEM) was used to analyse the characteristic of the solid residues. Experimental results shown that the reaction between the coal and the oxygen carrier become strong at a temperature of higher than 800°C. As the operation temperature rises, the reduction conversion rate increases. At the temperatures of 850°C, 900°C, and 950°C, the reduction conversion rates were 37.1%, 46.5%, and 54.1% respectively. However, SEM images show that at the temperature of higher than 950°C, the iron oxides become melted and sintered. The possible operation temperature should be kept around 900°C. When the mass ratios of coal to Fe3O4 were 5/95, 10/90, 15/85, and 20/80, the reduction conversion rates were 29.5%, 40.8%, 46.5%, and 46.6% respectively. With the increase of coal, the conversion rate goes up. But there exist an optimal ratio around 15/85. Comparisons based on different kinds of fuels show that the solid fuel with a higher volatile and a more developed pore structure is conducive to the reduction reactivity of the oxygen carrier.

  20. Linear versus non-linear measures of temporal variability in finger tapping and their relation to performance on open- versus closed-loop motor tasks: comparing standard deviations to Lyapunov exponents.

    PubMed

    Christman, Stephen D; Weaver, Ryan

    2008-05-01

    The nature of temporal variability during speeded finger tapping was examined using linear (standard deviation) and non-linear (Lyapunov exponent) measures. Experiment 1 found that right hand tapping was characterised by lower amounts of both linear and non-linear measures of variability than left hand tapping, and that linear and non-linear measures of variability were often negatively correlated with one another. Experiment 2 found that increased non-linear variability was associated with relatively enhanced performance on a closed-loop motor task (mirror tracing) and relatively impaired performance on an open-loop motor task (pointing in a dark room), especially for left hand performance. The potential uses and significance of measures of non-linear variability are discussed.

  1. Automatic Coupling Control of a Loop-Gap Resonator by a Variable Capacitor Attached Coupling Coil for EPR Measurements at 650 MHz

    NASA Astrophysics Data System (ADS)

    Yokoyama, Hidekastu; Sato, Toshiyuki; Ogata, Tateaki; Ohya, Hiroaki; Kamada, Hitoshi

    2001-03-01

    A coupling coil was fabricated that can electrically change the magnetic coupling with a loop-gap resonator (LGR) for EPR studies at 650 MHz. It is composed of a single-turn coil and a coupling control circuit that includes a varactor diode. The coarse control of the magnetic coupling is made by mechanically changing the distance between the LGR and single-turn coil. The fine control is obtained by changing the capacitance of the varactor diode that is connected in parallel with the single-turn coil. This capacitance is controlled by changing reverse voltage from a variable bias voltage source. Because this can be located far from the resonator, remote control of coupling of the LGR is possible. Automatic coupling control (ACC) was accomplished by negative feedback of the DC component in the radiowaves reflected from the LGR to the coupling control circuit when the LGR was irradiated precisely at its resonant frequency. To accomplish this, automatic frequency control (AFC) is used. In EPR measurements of a phantom that included a physiological saline solution containing a nitroxide radical, it was confirmed that the drifts in the coupling and resonant frequency caused by the perturbation of the resonant nature could be sufficiently compensated by the ACC and AFC systems. In the in vivo EPR studies, it was found that the deviation of coupling at the chest of a mouse is greater than that at the head of a rat, but the ACC system could compensate for the respiratory motions of a living animal.

  2. Patterns of the loop current system and regions of sea surface height variability in the eastern Gulf of Mexico revealed by the self-organizing maps

    NASA Astrophysics Data System (ADS)

    Liu, Yonggang; Weisberg, Robert H.; Vignudelli, Stefano; Mitchum, Gary T.

    2016-04-01

    The Self-Organizing Map (SOM), an unsupervised learning neural network, is employed to extract patterns evinced by the Loop Current (LC) system and to identify regions of sea surface height (SSH) variability in the eastern Gulf of Mexico (GoM) from 23 years (1993-2015) of altimetry data. Spatial patterns are characterized as different LC extensions and different stages in the process of LC eddy shedding. The temporal evolutions and the frequency of occurrences of these patterns are obtained, and the typical trajectories of the LC system progression on the SOM grid are investigated. For an elongated, northwest-extended, or west-positioned LC, it is common for the LC anticyclonic eddy (LCE) to separate and propagate into the western GoM, while an initially separated LCE in close proximity to the west Florida continental slope often reattaches to the LC and develops into an elongated LC, or reduces intensity locally before moving westward as a smaller eddy. Regions of differing SSH variations are also identified using the joint SOM-wavelet analysis. Along the general axis of the LC, SSH exhibits strong variability on time scales of 3 months to 2 years, also with energetic intraseasonal variations, which is consistent with the joint Empirical Orthogonal Function (EOF)-wavelet analysis. In the more peripheral regions, the SSH has a dominant seasonal variation that also projects across the coastal ocean. The SOM, when applied to both space and time domains of the same data, provides a powerful tool for diagnosing ocean processes from such different perspectives.

  3. Water maser variability over 20 years in a large sample of star-forming regions: the complete database

    NASA Astrophysics Data System (ADS)

    Felli, M.; Brand, J.; Cesaroni, R.; Codella, C.; Comoretto, G.; Di Franco, S.; Massi, F.; Moscadelli, L.; Nesti, R.; Olmi, L.; Palagi, F.; Panella, D.; Valdettaro, R.

    2007-12-01

    Context: Water vapor emission at 22 GHz from masers associated with star-forming regions is highly variable. Aims: We present a database of up to 20 years of monitoring of a sample of 43 masers within star-forming regions. The sample covers a large range of luminosities of the associated IRAS source and is representative of the entire population of H2O masers of this type. The database forms a good starting point for any further study of H2O maser variability. Methods: The observations were obtained with the Medicina 32-m radiotelescope, at a rate of 4-5 observations per year. Results: To provide a database that can be easily accessed through the web, we give for each source: plots of the calibrated spectra, the velocity-time-flux density plot, the light curve of the integrated flux, the lower and upper envelopes of the maser emission, the mean spectrum, and the rate of the maser occurrence as a function of velocity. Figures for just one source are given in the text for representative purposes. Figures for all the sources are given in electronic form the appendix. A discussion of the main properties of the H2O variability in our sample will be presented in a forthcoming paper. Based on observations with the Medicina radiotelescope operated by INAF - Istituto di Radioastronomia.

  4. Molecular variability in the Celleporella hyalina (Bryozoa; Cheilostomata) species complex: evidence for cryptic speciation from complete mitochondrial genomes.

    PubMed

    Waeschenbach, Andrea; Porter, Joanne S; Hughes, Roger N

    2012-09-01

    The bryozoan Celleporella has been shown to be composed of multiple, often cryptic, lineages. We sequenced two complete mitochondrial (mt) genomes of the Celleporella hyalina species complex from Wales, UK and Norway (i) to determine genetic divergence at the complete mt genome level, and (ii) to design new molecular markers for examining the interrelationships amongst the major lineages. In addressing (i), we estimated genetic divergence at three levels: (a) nucleotide diversity (π), (b) genome size, and (c) gene order. Genes nad4L, nad6, and atp8 showed the highest levels of divergence, and rrnL, rrnS, and cox1 showed the lowest levels. Inter-genome nucleotide divergence of protein-coding and ribosomal RNA genes, measured as π, was 0.21. The two genomes differed substantially in size, with the Norwegian genome being 2,573 base pairs (bp) longer than the Welsh genome, 17,265 and 14,692 bp, respectively. This difference in size is attributable to long non-coding regions present in the Norwegian genome. Both genomes exhibit similar gene orders, except for the translocation of one transfer RNA (trnA). Considering the high nucleotide diversity, genome size difference and change in gene order, these mt genomes are considered sufficiently divergent to have originated from two distinct species. In addressing (ii) we designed PCR primers that flank the most conserved regions of the genome: 1,300 bp of cox1 and a contiguous 2,000 bp fragment of rrnL + rrnS. The primers have yielded products for tissue from Wales, Norway, New Zealand, Alaska and Chile and should provide useful tools in establishing species- and population-level diversity within the Celleporella complex.

  5. Phylogenetic utility, and variability in structure and content, of complete mitochondrial genomes among genetic lineages of the Hawaiian anchialine shrimp Halocaridina rubra Holthuis 1963 (Atyidae:Decapoda).

    PubMed

    Justice, Joshua L; Weese, David A; Santos, Scott Ross

    2016-07-01

    The Atyidae are caridean shrimp possessing hair-like setae on their claws and are important contributors to ecological services in tropical and temperate fresh and brackish water ecosystems. Complete mitochondrial genomes have only been reported from five of the 449 species in the family, thus limiting understanding of mitochondrial genome evolution and the phylogenetic utility of complete mitochondrial sequences in the Atyidae. Here, comparative analyses of complete mitochondrial genomes from eight genetic lineages of Halocaridina rubra, an atyid endemic to the anchialine ecosystem of the Hawaiian Archipelago, are presented. Although gene number, order, and orientation were syntenic among genomes, three regions were identified and further quantified where conservation was substantially lower: (1) high length and sequence variability in the tRNA-Lys and tRNA-Asp intergenic region; (2) a 317-bp insertion between the NAD6 and CytB genes confined to a single lineage and representing a partial duplication of CytB; and (3) the putative control region. Phylogenetic analyses utilizing complete mitochondrial sequences provided new insights into relationships among the H. rubra genetic lineages, with the topology of one clade correlating to the geologic sequence of the islands. However, deeper nodes in the phylogeny lacked bootstrap support. Overall, our results from H. rubra suggest intra-specific mitochondrial genomic diversity could be underestimated across the Metazoa since the vast majority of complete genomes are from just a single individual of a species.

  6. Testing the Pairs-Reflection Model with X-Ray Spectral Variability and X-Ray Properties of Complete Samples of Radio-Selected BL Lacertae Objects

    NASA Technical Reports Server (NTRS)

    Urry, C. Megan

    1997-01-01

    This grant was awarded to Dr. C. Megan Urry of the Space Telescope Science Institute in response to two successful ADP proposals to use archival Ginga and Rosat X-ray data for 'Testing the Pairs-Reflection model with X-Ray Spectral Variability' (in collaboration with Paola Grandi, now at the University of Rome) and 'X-Ray Properties of Complete Samples of Radio-Selected BL Lacertae Objects' (in collaboration with then-graduate student Rita Sambruna, now a post-doc at Goddard Space Flight Center). In addition, post-docs Joseph Pesce and Elena Pian, and graduate student Matthew O'Dowd, have worked on several aspects of these projects. The grant was originally awarded on 3/01/94; this report covers the full period, through May 1997. We have completed our project on the X-ray properties of radio-selected BL Lacs.

  7. Genomic cartography of varicella-zoster virus: a complete genome-based analysis of strain variability with implications for attenuation and phenotypic differences.

    PubMed

    Tyler, S D; Peters, G A; Grose, C; Severini, A; Gray, M J; Upton, C; Tipples, G A

    2007-03-15

    In order to gain a better perspective on the true variability of varicella-zoster virus (VZV) and to catalogue the location and number of differences, 11 new complete genome sequences were compared with those previously in the public domain (18 complete genomes in total). Three of the newly sequenced genomes were derived from a single strain in order to assess variations that can occur during serial passage in cell culture. The analysis revealed that while VZV is relatively stable genetically it does posses a certain degree of variability. The reiteration regions, origins of replication and intergenic homopolymer regions were all found to be variable between strains as well as within a given strain. In addition, the terminal viral sequences were found to vary within and between strains specifically at the 3' end of the genome. Analysis of single nucleotide polymorphisms (SNPs) identified a total of 557 variable sites, 451 of which were found in coding regions and resulted in 187 different in amino acid substitutions. A comparison of the SNPs present in the two gE mutant strains, VZV-MSP and VZV-BC, suggested that the missense mutation in gE was primarily responsible for the accelerated cell spread phenotype. Some of the variations noted with high passage in cell culture are consistent with variations seen in the IE62 gene of the vaccine strains (S628G, R958G and I1260V) that may help in pinpointing variations essential for attenuation. Although VZV has been considered to be one of the most genetically stable human herpesviruses, this initial assessment of genomic VZV cartography provides insight into ORFs with previously unreported variations.

  8. Mining protein loops using a structural alphabet and statistical exceptionality

    PubMed Central

    2010-01-01

    Background Protein loops encompass 50% of protein residues in available three-dimensional structures. These regions are often involved in protein functions, e.g. binding site, catalytic pocket... However, the description of protein loops with conventional tools is an uneasy task. Regular secondary structures, helices and strands, have been widely studied whereas loops, because they are highly variable in terms of sequence and structure, are difficult to analyze. Due to data sparsity, long loops have rarely been systematically studied. Results We developed a simple and accurate method that allows the description and analysis of the structures of short and long loops using structural motifs without restriction on loop length. This method is based on the structural alphabet HMM-SA. HMM-SA allows the simplification of a three-dimensional protein structure into a one-dimensional string of states, where each state is a four-residue prototype fragment, called structural letter. The difficult task of the structural grouping of huge data sets is thus easily accomplished by handling structural letter strings as in conventional protein sequence analysis. We systematically extracted all seven-residue fragments in a bank of 93000 protein loops and grouped them according to the structural-letter sequence, named structural word. This approach permits a systematic analysis of loops of all sizes since we consider the structural motifs of seven residues rather than complete loops. We focused the analysis on highly recurrent words of loops (observed more than 30 times). Our study reveals that 73% of loop-lengths are covered by only 3310 highly recurrent structural words out of 28274 observed words). These structural words have low structural variability (mean RMSd of 0.85 Å). As expected, half of these motifs display a flanking-region preference but interestingly, two thirds are shared by short (less than 12 residues) and long loops. Moreover, half of recurrent motifs exhibit a

  9. Loop-to-loop coupling.

    SciTech Connect

    Warne, Larry Kevin; Lucero, Larry Martin; Langston, William L.; Salazar, Robert Austin; Coleman, Phillip Dale; Basilio, Lorena I.; Bacon, Larry Donald

    2012-05-01

    This report estimates inductively-coupled energy to a low-impedance load in a loop-to-loop arrangement. Both analytical models and full-wave numerical simulations are used and the resulting fields, coupled powers and energies are compared. The energies are simply estimated from the coupled powers through approximations to the energy theorem. The transmitter loop is taken to be either a circular geometry or a rectangular-loop (stripline-type) geometry that was used in an experimental setup. Simple magnetic field models are constructed and used to estimate the mutual inductance to the receiving loop, which is taken to be circular with one or several turns. Circuit elements are estimated and used to determine the coupled current and power (an equivalent antenna picture is also given). These results are compared to an electromagnetic simulation of the transmitter geometry. Simple approximate relations are also given to estimate coupled energy from the power. The effect of additional loads in the form of attached leads, forming transmission lines, are considered. The results are summarized in a set of susceptibility-type curves. Finally, we also consider drives to the cables themselves and the resulting common-to-differential mode currents in the load.

  10. Flight Testing of the Capillary Pumped Loop 3 Experiment

    NASA Technical Reports Server (NTRS)

    Ottenstein, Laura; Butler, Dan; Ku, Jentung; Cheung, Kwok; Baldauff, Robert; Hoang, Triem

    2002-01-01

    The Capillary Pumped Loop 3 (CAPL 3) experiment was a multiple evaporator capillary pumped loop experiment that flew in the Space Shuttle payload bay in December 2001 (STS-108). The main objective of CAPL 3 was to demonstrate in micro-gravity a multiple evaporator capillary pumped loop system, capable of reliable start-up, reliable continuous operation, and heat load sharing, with hardware for a deployable radiator. Tests performed on orbit included start-ups, power cycles, low power tests (100 W total), high power tests (up to 1447 W total), heat load sharing, variable/fixed conductance transition tests, and saturation temperature change tests. The majority of the tests were completed successfully, although the experiment did exhibit an unexpected sensitivity to shuttle maneuvers. This paper describes the experiment, the tests performed during the mission, and the test results.

  11. Wilson Loop Diagrams and Positroids

    NASA Astrophysics Data System (ADS)

    Agarwala, Susama; Marin-Amat, Eloi

    2017-03-01

    In this paper, we study a new application of the positive Grassmannian to Wilson loop diagrams (or MHV diagrams) for scattering amplitudes in N= 4 Super Yang-Mill theory ( N = 4 SYM). There has been much interest in studying this theory via the positive Grassmannians using BCFW recursion. This is the first attempt to study MHV diagrams for planar Wilson loop calculations (or planar amplitudes) in terms of positive Grassmannians. We codify Wilson loop diagrams completely in terms of matroids. This allows us to apply the combinatorial tools in matroid theory used to identify positroids (non-negative Grassmannians) to Wilson loop diagrams. In doing so, we find that certain non-planar Wilson loop diagrams define positive Grassmannians. While non-planar diagrams do not have physical meaning, this finding suggests that they may have value as an algebraic tool, and deserve further investigation.

  12. Loop-bed combustion apparatus

    DOEpatents

    Shang, Jer-Yu; Mei, Joseph S.; Slagle, Frank D.; Notestein, John E.

    1984-01-01

    The present invention is directed to a combustion apparatus in the configuration of a oblong annulus defining a closed loop. Particulate coal together with a sulfur sorbent such as sulfur or dolomite is introduced into the closed loop, ignited, and propelled at a high rate of speed around the loop. Flue gas is withdrawn from a location in the closed loop in close proximity to an area in the loop where centrifugal force imposed upon the larger particulate material maintains these particulates at a location spaced from the flue gas outlet. Only flue gas and smaller particulates resulting from the combustion and innerparticle grinding are discharged from the combustor. This structural arrangement provides increased combustion efficiency due to the essentially complete combustion of the coal particulates as well as increased sulfur absorption due to the innerparticle grinding of the sorbent which provides greater particle surface area.

  13. High levels of genetic variability and differentiation in hilsa shad, Tenualosa ilisha (Clupeidae, Clupeiformes) populations revealed by PCR-RFLP analysis of the mitochondrial DNA D-loop region

    PubMed Central

    2009-01-01

    The hilsa shad, Tenualosa ilisha (Clupeidae, Clupeiformes) is an important anadromous clupeid species from the Western division of the Indo-Pacific region. It constitutes the largest single fishable species in Bangladesh. Information on genetic variability and population structure is very important for both management and conservation purposes. Past reports on the population structure of T. ilisha involving morphometric, allozyme and RAPD analyses are contradictory. We examined genetic variability and divergence in two riverine (the Jamuna and the Meghna), two estuarine (Kuakata and Sundarbans) and one marine (Cox's Bazar) populations of T. ilisha by applying PCR-RFLP analysis of the mtDNA D-loop region. The amplified PCR products were restricted with four restriction enzymes namely, XbaI, EcoRI, EcoRV, and HaeIII. High levels of haplotype and gene diversity within and significant differentiations among, populations of T. ilisha were observed in this study. Significant FST values indicated differentiation among the river, estuary and marine populations. The UPGMA dendrogram based on genetic distance resulted in two major clusters, although, these were subsequently divided into three, corresponding to the riverine, estuarine and marine populations. The study underlines the usefulness of RFLP of mtDNA D-loop region as molecular markers, and detected at least two differentiated populations of T. ilisha in Bangladesh waters. PMID:21637667

  14. Ashtekar variables

    NASA Astrophysics Data System (ADS)

    Ashtekar, Abhay

    2015-05-01

    In the spirit of Scholarpedia, this invited article is addressed to students and younger researchers. It provides the motivation and background material, a summary of the main physical ideas, mathematical structures and results, and an outline of applications of the connection variables for general relativity. These variables underlie both the canonical/Hamiltonian and the spinfoam/path integral approaches in loop quantum gravity.

  15. All orders results for self-crossing Wilson loops mimicking double parton scattering

    DOE PAGES

    Dixon, Lance J.; Esterlis, Ilya

    2016-07-21

    Loop-level scattering amplitudes for massless particles have singularities in regions where tree amplitudes are perfectly smooth. For example, a 2 → 4 gluon scattering process has a singularity in which each incoming gluon splits into a pair of gluons, followed by a pair of 2 → 2 collisions between the gluon pairs. This singularity mimics double parton scattering because it occurs when the transverse momentum of a pair of outgoing gluons vanishes. The singularity is logarithmic at fixed order in perturbation theory. We exploit the duality between scattering amplitudes and polygonal Wilson loops to study six-point amplitudes in this limitmore » to high loop order in planar N = 4 super-Yang-Mills theory. The singular configuration corresponds to the limit in which a hexagonal Wilson loop develops a self-crossing. The singular terms are governed by an evolution equation, in which the hexagon mixes into a pair of boxes; the mixing back is suppressed in the planar (large N c) limit. Because the kinematic dependence of the box Wilson loops is dictated by (dual) conformal invariance, the complete kinematic dependence of the singular terms for the self-crossing hexagon on the one nonsingular variable is determined to all loop orders. The complete logarithmic dependence on the singular variable can be obtained through nine loops, up to a couple of constants, using a correspondence with the multi-Regge limit. As a byproduct, we obtain a simple formula for the leading logs to all loop orders. Furthermore, we also show that, although the MHV six-gluon amplitude is singular, remarkably, the transcendental functions entering the non-MHV amplitude are finite in the same limit, at least through four loops.« less

  16. All orders results for self-crossing Wilson loops mimicking double parton scattering

    SciTech Connect

    Dixon, Lance J.; Esterlis, Ilya

    2016-07-21

    Loop-level scattering amplitudes for massless particles have singularities in regions where tree amplitudes are perfectly smooth. For example, a 2 → 4 gluon scattering process has a singularity in which each incoming gluon splits into a pair of gluons, followed by a pair of 2 → 2 collisions between the gluon pairs. This singularity mimics double parton scattering because it occurs when the transverse momentum of a pair of outgoing gluons vanishes. The singularity is logarithmic at fixed order in perturbation theory. We exploit the duality between scattering amplitudes and polygonal Wilson loops to study six-point amplitudes in this limit to high loop order in planar N = 4 super-Yang-Mills theory. The singular configuration corresponds to the limit in which a hexagonal Wilson loop develops a self-crossing. The singular terms are governed by an evolution equation, in which the hexagon mixes into a pair of boxes; the mixing back is suppressed in the planar (large N c) limit. Because the kinematic dependence of the box Wilson loops is dictated by (dual) conformal invariance, the complete kinematic dependence of the singular terms for the self-crossing hexagon on the one nonsingular variable is determined to all loop orders. The complete logarithmic dependence on the singular variable can be obtained through nine loops, up to a couple of constants, using a correspondence with the multi-Regge limit. As a byproduct, we obtain a simple formula for the leading logs to all loop orders. Furthermore, we also show that, although the MHV six-gluon amplitude is singular, remarkably, the transcendental functions entering the non-MHV amplitude are finite in the same limit, at least through four loops.

  17. All orders results for self-crossing Wilson loops mimicking double parton scattering

    NASA Astrophysics Data System (ADS)

    Dixon, Lance J.; Esterlis, Ilya

    2016-07-01

    Loop-level scattering amplitudes for massless particles have singularities in regions where tree amplitudes are perfectly smooth. For example, a 2 → 4 gluon scattering process has a singularity in which each incoming gluon splits into a pair of gluons, followed by a pair of 2 → 2 collisions between the gluon pairs. This singularity mimics double parton scattering because it occurs when the transverse momentum of a pair of outgoing gluons vanishes. The singularity is logarithmic at fixed order in perturbation theory. We exploit the duality between scattering amplitudes and polygonal Wilson loops to study six-point amplitudes in this limit to high loop order in planar {N} = 4 super-Yang-Mills theory. The singular configuration corresponds to the limit in which a hexagonal Wilson loop develops a self-crossing. The singular terms are governed by an evolution equation, in which the hexagon mixes into a pair of boxes; the mixing back is suppressed in the planar (large N c) limit. Because the kinematic dependence of the box Wilson loops is dictated by (dual) conformal invariance, the complete kinematic dependence of the singular terms for the self-crossing hexagon on the one nonsingular variable is determined to all loop orders. The complete logarithmic dependence on the singular variable can be obtained through nine loops, up to a couple of constants, using a correspondence with the multi-Regge limit. As a byproduct, we obtain a simple formula for the leading logs to all loop orders. We also show that, although the MHV six-gluon amplitude is singular, remarkably, the transcendental functions entering the non-MHV amplitude are finite in the same limit, at least through four loops.

  18. Phylogenetic relationships of intraspecific forms of the house mouse Mus musculus: Analysis of variability of the control region (D-loop) of mitochondrial DNA.

    PubMed

    Maltsev, A N; Stakheev, V V; Bogdanov, A S; Fomina, E S; Kotenkova, E V

    2015-11-01

    Analysis of the control region of mitochondrial DNA (mtDNA) or D-loop of 96 house mice (Mus musculus) from Russia, Moldova, Armenia, Azerbaijan, Kazakhstan, and Turkmenistan has been used to reconstruct the phylogenetic relationships and phylogeographic patterns of intraspecific forms. New data on the phylogenetic structure of the house mouse are presented. Three phylogroups can be reliably distinguished in the eastern part of the M. musculus species range, the first one mainly comprising the haplotypes of mice from Transcaucasia (Armenia); the second one, the haplotypes of mice from Kazakhstan; and the third one, the haplotypes of mice from Siberia and some other regions. The morphological subspecies M. m. wagneri and M. m. gansuensis have proved to be genetically heterogeneous and did not form discrete phylogroups in the phylogenetic tree.

  19. Selection of aminoacyl-tRNAs at sense codons: the size of the tRNA variable loop determines whether the immediate 3' nucleotide to the codon has a context effect.

    PubMed Central

    Curran, J F; Poole, E S; Tate, W P; Gross, B L

    1995-01-01

    Codon context can affect translational efficiency by several molecular mechanisms. The base stacking interactions between a codon-anticodon complex and the neighboring nucleotide immediately 3' can facilitate translation by amber suppressors and the tRNA structure is also known to modulate the sensitivity to context. In this study the relative rates of aminoacyl-tRNA selection were measured at four sense codons (UGG, CUC, UUC and UCA), in all four 3' nucleotide contexts, through direct competition with a programmed frameshift at a site derived from the release factor 2 gene. Two codons (UGG and UUC) are read by tRNAs with small variable regions and their rates of aminoacyl-tRNA selection correlated with the potential base stacking strength of the 3' neighboring nucleotide. The other two codons (CUC and UCA) are read by tRNAs with large variable regions and the rate of selection of the aminoacyl-tRNAs in these cases varied little among the four contexts. Re-examination of published data on amber suppression also revealed an inverse correlation between context sensitivity and the size of the variable region. Collectively the data suggest that a large variable loop in a tRNA decreases the influence of the 3' context on tRNA selection, probably by strengthening tRNA-ribosomal interactions. PMID:7479072

  20. Phylogenetic analysis and comparison between cow and buffalo (including Egyptian buffaloes) mitochondrial displacement-loop regions.

    PubMed

    Ramadan, Hassan A I; El-Hefnawi, Mahmoud M

    2008-08-01

    Mitochondrial DNA (mtDNA) analysis has been used extensively for phylogenetic analysis studies and systematics. The displacement loop (D-loop) region inside the mtDNA is a non-coding part whose analysis can indicate variations between closely related populations. This paper reports for the first time the characterization and analysis of the complete sequence of the D-loop region from Egyptian buffaloes and analysis in conjunction with previously published Indian and European Bubalus bubalis and Bos sub-tribe sequences. In the entire D-loop of the Egyptian buffaloes, we identified four haplotypes and nine polymorphic sites from the nine sequenced D-loop regions--while in the studied set of buffaloes we identified 28 polymorphic sites in the entire D-loop, and 49 polymorphic sites in the case of cows. Alignment between buffaloes and cows to evaluate the characteristics of the D-loop region showed that the second region of the conserved sequence block (CSB2) is apparently the most variable region in the D-loop between cows and buffaloes, with four insertions in all buffaloes and two substitutions, followed by the second region of the extended termination associated sequence (ETAS2) with a substitution rate of 1/10. The Egyptian buffaloes were shown to be closest to the Italian counterparts, exemplifying the closeness of ethnicity and the history of civilization of that region.

  1. Suppressing Transients In Digital Phase-Locked Loops

    NASA Technical Reports Server (NTRS)

    Thomas, J. B.

    1993-01-01

    Loop of arbitrary order starts in steady-state lock. Method for initializing variables of digital phase-locked loop reduces or eliminates transients in phase and frequency typically occurring during acquisition of lock on signal or when changes made in values of loop-filter parameters called "loop constants". Enables direct acquisition by third-order loop without prior acquisition by second-order loop of greater bandwidth, and eliminates those perturbations in phase and frequency lock occurring when loop constants changed by arbitrarily large amounts.

  2. Water Stream "Loop-the-Loop"

    ERIC Educational Resources Information Center

    Jefimenko, Oleg

    1974-01-01

    Discusses the design of a modified loop-the-loop apparatus in which a water stream is used to illustrate centripetal forces and phenomena of high-velocity hydrodynamics. Included are some procedures of carrying out lecture demonstrations. (CC)

  3. High temperature loop heat pipes

    SciTech Connect

    Anderson, W.G.; Bland, J.J.; Fershtater, Y.; Goncharov, K.A.; Nikitkin, M.; Juhasz, A.

    1995-12-31

    Advantages of loop heat pipes over conventional heat pipes include self-priming during start-up, improved tolerance for noncondensible gas, and ability for ground testing in any orientation. The applications for high temperature, alkali-metal working fluid loop heat pipes include space radiators, and bimodal systems. A high temperature loop heat pipe was fabricated and tested at 850 K, using cesium as the working fluid. Previous loop heat pipes were tested with ambient temperature working fluids at temperatures below about 450 K. The loop heat pipe had a titanium envelope, and a titanium aluminide wick. The maximum cesium loop heat pipe power was only about 600 watts, which was lower the predicted 1,000 W power. The power limitation may be due to a wettability problem with the cesium not completely wetting the titanium aluminide wick. This would reduce the pumping capability of the wick, and the maximum power that the heat pipe could carry. This problem could be solved by using a refractory metal powder wick, since the alkali metals are known to wet refractory metal wicks.

  4. High AN1 variability and interaction with basic helix-loop-helix co-factors related to anthocyanin biosynthesis in potato leaves.

    PubMed

    D'Amelia, Vincenzo; Aversano, Riccardo; Batelli, Giorgia; Caruso, Immacolata; Castellano Moreno, Mar; Castro-Sanz, Ana Beatriz; Chiaiese, Pasquale; Fasano, Carlo; Palomba, Francesca; Carputo, Domenico

    2014-11-01

    AN1 is a regulatory gene that promotes anthocyanin biosynthesis in potato tubers and encodes a R2R3 MYB transcription factor. However, no clear evidence implicates AN1 in anthocyanin production in leaves, where these pigments might enhance environmental stress tolerance. In our study we found that AN1 displays intraspecific sequence variability in both coding/non-coding regions and in the promoter, and that its expression is associated with high anthocyanin content in leaves of commercial potatoes. Expression analysis provided evidence that leaf pigmentation is associated to AN1 expression and that StJAF13 acts as putative AN1 co-regulator for anthocyanin gene expression in leaves of the red leaf variety 'Magenta Love,' while a concomitant expression of StbHLH1 may contribute to anthocyanin accumulation in leaves of 'Double Fun.' Yeast two-hybrid experiments confirmed that AN1 interacts with StbHLH1 and StJAF13 and the latter interaction was verified and localized in the cell nucleus by bimolecular fluorescence complementation assays. In addition, transgenic tobacco (Nicotiana tabacum) overexpressing a combination of either AN1 with StJAF13 or AN1 with StbHLH1 showed deeper purple pigmentation with respect to AN1 alone. This further confirmed AN1/StJAF13 and AN1/StbHLH1 interactions. Our findings demonstrate that the classical loci identified for potato leaf anthocyanin accumulation correspond to AN1 and may represent an important step to expand our knowledge on the molecular mechanisms underlying anthocyanin biosynthesis in different plant tissues.

  5. Study of the Open Loop and Closed Loop Oscillator Techniques

    SciTech Connect

    Imel, George R.; Baker, Benjamin; Riley, Tony; Langbehn, Adam; Aryal, Harishchandra; Benzerga, M. Lamine

    2015-04-11

    This report presents the progress and completion of a five-year study undertaken at Idaho State University of the measurement of very small worth reactivity samples comparing open and closed loop oscillator techniques.The study conclusively demonstrated the equivalency of the two techniques with regard to uncertainties in reactivity values, i.e., limited by reactor noise. As those results are thoroughly documented in recent publications, in this report we will concentrate on the support work that was necessary. For example, we describe in some detail the construction and calibration of a pilot rod for the closed loop system. We discuss the campaign to measure the required reactor parameters necessary for inverse-kinetics. Finally, we briefly discuss the transfer of the open loop technique to other reactor systems.

  6. Fast flux locked loop

    DOEpatents

    Ganther, Jr., Kenneth R.; Snapp, Lowell D.

    2002-09-10

    A flux locked loop for providing an electrical feedback signal, the flux locked loop employing radio-frequency components and technology to extend the flux modulation frequency and tracking loop bandwidth. The flux locked loop of the present invention has particularly useful application in read-out electronics for DC SQUID magnetic measurement systems, in which case the electrical signal output by the flux locked loop represents an unknown magnetic flux applied to the DC SQUID.

  7. The preprocessed doacross loop

    NASA Technical Reports Server (NTRS)

    Saltz, Joel H.; Mirchandaney, Ravi

    1990-01-01

    Dependencies between loop iterations cannot always be characterized during program compilation. Doacross loops typically make use of a-priori knowledge of inter-iteration dependencies to carry out required synchronizations. A type of doacross loop is proposed that allows the scheduling of iterations of a loop among processors without advance knowledge of inter-iteration dependencies. The method proposed for loop iterations requires that parallelizable preprocessing and postprocessing steps be carried out during program execution.

  8. OPE for super loops

    NASA Astrophysics Data System (ADS)

    Sever, Amit; Vieira, Pedro; Wang, Tianheng

    2011-11-01

    We extend the Operator Product Expansion for Null Polygon Wilson loops to the Mason-Skinner-Caron-Huot super loop dual to non MHV gluon amplitudes. We explain how the known tree level amplitudes can be promoted into an infinite amount of data at any loop order in the OPE picture. As an application, we re-derive all one loop NMHV six gluon amplitudes by promoting their tree level expressions. We also present some new all loops predictions for these amplitudes.

  9. Task completion report for investigating why output signal-variable values differ from their output component-parameter values in test problem MST2

    SciTech Connect

    Steinke, R.G.

    1997-09-10

    Signal-variable values and their component-parameter values differ in an end-of-timestep edit to the TRCOUT and TRCGRF files because signal variables have beginning-of-timestep values, and component parameters have end-of-timestep values. Oscillatory divergence in the MST2 standard test problem after 9000 s occurs because of TRAC-P`s numerical evaluation at a 1000 material Courant number. The magnitude of that divergence has diminished by a factor of 3.5 from Version 5.3.01 to 5.4.15 and by a factor of 25 from Version 5.4.15 to 5.4.28. That divergence can be eliminated by evaluating MST2 with a maximum material Courant number of 500.

  10. Variability in Risk Assessment and Management Plan (RAMP) scores completed as part of the Ontario Johne's Education and Management Assistance Program(2010-2013).

    PubMed

    Pieper, Laura; DeVries, Trevor J; Sorge, Ulrike S; Godkin, Ann; Hand, Karen J; Perkins, Nicole R; Imada, Jamie; Kelton, David F

    2015-04-01

    As a proactive measure toward controlling the nontreatable and contagious Johne's disease in cattle, the Ontario dairy industry launched the voluntary Ontario Johne's Education and Management Assistance Program in 2010. The objective of this study was to describe the results of the first 4 yr of the program and to investigate the variability in Risk Assessment and Management Plan (RAMP) scores associated with the county, veterinary clinic, and veterinarian. Of 4,158 Ontario dairy farms, 2,153 (51.8%) participated in the program between January 2010 and August 2013. For this study, RAMP scores and whole-herd milk or serum ELISA results were available from 2,103 farms. Herd-level ELISA-positive prevalence (herds with one or more test-positive cows were considered positive) was 27.2%. Linear mixed model analysis revealed that the greatest RAMP score variability was at the veterinarian level (24.2%), with relatively little variability at the county and veterinary clinic levels. Consequently, the annual RAMP should be done by the same veterinarian to avoid misleading or discouraging results.

  11. SWUSV: a microsatellite mission for space weather early forecasting of major flares and CMEs and the complete monitoring of the ultraviolet solar variability influence on climate

    NASA Astrophysics Data System (ADS)

    Damé, Luc

    The SWUSV (Space Weather & Ultraviolet Solar Variability) proposed microsatellite mission encompasses three major scientific objectives: (1) Space Weather including the prediction and detection of major eruptions and coronal mass ejections (using Lyman-Alpha and Herzberg continuum imaging and H-Alpha ground support); (2) solar forcing on the climate through radiation and their interactions with the local stratosphere (UV spectral irradiance from 180 to 400 nm by bands of 10 to 20 nm, including ozone, plus Lyman-Alpha and the CN bandhead); (3) simultaneous local radiative budget of the Earth, UV to IR, with an accuracy better than 1% in differential. The mission is on a sun-synchronous polar orbit and proposes 5 instruments to the model payload: SUAVE (Solar Ultraviolet Advanced Variability Experiment), an optimized telescope for FUV (Lyman-Alpha) and MUV (200-220 nm Herzberg continuum) imaging (sources of variability); UPR (Ultraviolet Passband Radiometers), with 64 UV filter radiometers; a vector magnetometer; thermal plasma measurements and Langmuir probes; and a total and spectral solar irradiance and Earth radiative budget ensemble (SERB, Solar irradiance & Earth Radiative Budget). SWUSV is proposed as a small mission to CNES and to ESA for a possible flight as early as 2020-2021. With opening to Chinese collaboration (ESA-CAS Small Mission) a further instrument could be added (HEBS, High Energy Burst Spectrometers) to reinforced Space Weather flares prediction objectives.

  12. COLD TEST LOOP INTEGRATED TEST LOOP RESULTS

    SciTech Connect

    Abraham, TJ

    2003-10-22

    A testing facility (Cold Test Loop) was constructed and operated to demonstrate the efficacy of the Accelerated Waste Retrieval (AWR) Project's planned sluicing approach to the remediation of Silos 1 and 2 at the Fernald Environmental Management Project near Cincinnati, Ohio. The two silos contain almost 10,000 tons of radium-bearing low-level waste, which consists primarily of solids of raffinates from processing performed on ores from the Democratic Republic of Congo (commonly referred to as ''Belgium Congo ores'') for the recovery of uranium. These silos are 80 ft in diameter, 36 ft high to the center of the dome, and 26.75 ft to the top of the vertical side walls. The test facility contained two test systems, each designed for a specific purpose. The first system, the Integrated Test Loop (ITL), a near-full-scale plant including the actual equipment to be installed at the Fernald Site, was designed to demonstrate the sluicing operation and confirm the selection of a slurry pump, the optimal sluicing nozzle operation, and the preliminary design material balance. The second system, the Component Test Loop (CTL), was designed to evaluate many of the key individual components of the waste retrieval system over an extended run. The major results of the initial testing performed during July and August 2002 confirmed that the AWR approach to sluicing was feasible. The ITL testing confirmed the following: (1) The selected slurry pump (Hazleton 3-20 type SHW) performed well and is suitable for AWR application. However, the pump's motor should be upgraded to a 200-hp model and be driven by a 150-hp variable-frequency drive (VFD). A 200-hp VFD is not much more expensive and would allow the pump to operate at full speed. (2) The best nozzle performance was achieved by using 15/16-in. nozzles operated alternately. This configuration appeared to most effectively mine the surrogate. (3) The Solartron densitometer, which was tested as an alternative mass flow measurement

  13. Complete deficiency of methylenetetrahydrofolate reductase in mice is associated with impaired retinal function and variable mortality, hematological profiles, and reproductive outcomes.

    PubMed

    Lawrance, Andrea K; Racine, Julie; Deng, Liyuan; Wang, Xiaoling; Lachapelle, Pierre; Rozen, Rima

    2011-02-01

    Severe deficiency of methylenetetrahydrofolate reductase (MTHFR) with homocystinuria can result in early demise or later-onset neurological impairment, including developmental delay, motor dysfunction, and seizures. We previously characterized BALB/c Mthfr (-/-)mice as a model for this disorder and have recently backcrossed the disrupted allele onto the C57Bl/6 background to examine the variable phenotypes in MTHFR deficiency. Compared with BALB/c Mthfr (-/-)mice, C57Bl/6 Mthfr (-/-)mice have enhanced survival rates (81% vs 26.5%). Four-day-old BALB/c mutant pups had lower body, brain, and spleen weights relative to their wild-type counterparts compared with C57Bl/6 mutants. Pregnant BALB/c Mthfr (+/-)mice had increased resorptions and embryonic delays compared with wild-type littermates, whereas these outcomes in C57Bl/6 c Mthfr (+/-)mice were similar to those of wild-type C57Bl/6 mice. BALB/c-mutant pups had altered hematological profiles (higher hematocrit, hemoglobin, and white blood cell counts, with lower platelet counts) compared with C57Bl/6 mutants. Mutants of both strains had similar degrees of hepatic steatosis, hepatic activity of betaine:homocysteine methyltransferase, and altered cerebellar histology. Electroretinograms (ERG) in C57Bl/6 Mthfr (-/-)mice revealed decreased amplitude of scotopic and photopic waves in 6-week-old mice, with normalized ERGs at 13 weeks. Plasma homocysteine was modestly higher in C57Bl/6 compared with BALB/c mice. Our results emphasize the variable presentation of MTHFR deficiency in different genetic backgrounds and suggest that plasma homocysteine is not a predictor of severity. In addition, our novel findings of decreased spleen weights, thrombocytopenia, and impaired retinal function warrant investigation in patients with severe MTHFR deficiency or other forms of homocystinuria.

  14. The complete sequence of a Spanish isolate of Broad bean wilt virus 1 (BBWV-1) reveals a high variability and conserved motifs in the genus Fabavirus.

    PubMed

    Ferrer, R M; Guerri, J; Luis-Arteaga, M S; Moreno, P; Rubio, L

    2005-10-01

    The genome of a Spanish isolate of Broad bean wilt virus-1 (BBWV-1) was completely sequenced and compared with available sequences of other isolates of the genus Fabavirus (BBWV-1 and BBWV-2). This consisted of two RNAs of 5814 and 3431 nucleotides, respectively, and their organization was similar to that of other members of the family Comoviridae. Its mean nucleotide identity with a BBWV-1 American isolate was 81.5%, and between 59.8 and 63.5% with seven BBWV-2 isolates. Our analysis showed sequence stretches in the 5' non-coding regions which are conserved in both genomic RNAs and in BBWV-1 and BBWV-2 isolates.

  15. Pseudonoise code tracking loop

    NASA Technical Reports Server (NTRS)

    Laflame, D. T. (Inventor)

    1980-01-01

    A delay-locked loop is presented for tracking a pseudonoise (PN) reference code in an incoming communication signal. The loop is less sensitive to gain imbalances, which can otherwise introduce timing errors in the PN reference code formed by the loop.

  16. Genetic characteristics of the complete feline kobuvirus genome.

    PubMed

    Choi, Jeong-Won; Lee, Myoung-Heon; Lee, Kyoung-Ki; Oem, Jae-Ku

    2015-02-01

    We sequenced the complete genome of a feline kobuvirus and determined relationships with other kobuviruses. This kobuvirus has an 8,269-nucleotide-long RNA genome, excluding the poly(A) tail. The genome contains a 7,311-bp open reading frame (ORF) encoding a putative polyprotein precursor of 2,437 amino acids, a 717-bp 5'-untranslated region (UTR), and a 241-bp 3'-UTR. The L protein sequence was found to be the most variable region in the feline kobuvirus genome. Interestingly, the 5'-UTR B and C stem-loops were conserved as observed with other kobuviruses; however, a secondary structure corresponding to stem-loop A was not found in the full length 5'-UTR sequence. Phylogenetic tree analysis showed that kobuviruses can be divided into 3 main groups. The feline kobuvirus belongs to the Aichivirus A species containing Aichivirus, mouse kobuvirus, and canine kobuvirus.

  17. Assisted closed-loop optimization of SSVEP-BCI efficiency

    PubMed Central

    Fernandez-Vargas, Jacobo; Pfaff, Hanns U.; Rodríguez, Francisco B.; Varona, Pablo

    2012-01-01

    We designed a novel assisted closed-loop optimization protocol to improve the efficiency of brain-computer interfaces (BCI) based on steady state visually evoked potentials (SSVEP). In traditional paradigms, the control over the BCI-performance completely depends on the subjects' ability to learn from the given feedback cues. By contrast, in the proposed protocol both the subject and the machine share information and control over the BCI goal. Generally, the innovative assistance consists in the delivery of online information together with the online adaptation of BCI stimuli properties. In our case, this adaptive optimization process is realized by (1) a closed-loop search for the best set of SSVEP flicker frequencies and (2) feedback of actual SSVEP magnitudes to both the subject and the machine. These closed-loop interactions between subject and machine are evaluated in real-time by continuous measurement of their efficiencies, which are used as online criteria to adapt the BCI control parameters. The proposed protocol aims to compensate for variability in possibly unknown subjects' state and trait dimensions. In a study with N = 18 subjects, we found significant evidence that our protocol outperformed classic SSVEP-BCI control paradigms. Evidence is presented that it takes indeed into account interindividual variabilities: e.g., under the new protocol, baseline resting state EEG measures predict subjects' BCI performances. This paper illustrates the promising potential of assisted closed-loop protocols in BCI systems. Probably their applicability might be expanded to innovative uses, e.g., as possible new diagnostic/therapeutic tools for clinical contexts and as new paradigms for basic research. PMID:23443214

  18. Improved determination of dynamic balance using the centre of mass and centre of pressure inclination variables in a complete golf swing cycle.

    PubMed

    Choi, Ahnryul; Sim, Taeyong; Mun, Joung Hwan

    2016-01-01

    Golf requires proper dynamic balance to accurately control the club head through a harmonious coordination of each human segment and joint. In this study, we evaluated the ability for dynamic balance during a golf swing by using the centre of mass (COM)-centre of pressure (COP) inclination variables. Twelve professional, 13 amateur and 10 novice golfers participated in this study. Six infrared cameras, two force platforms and SB-Clinic software were used to measure the net COM and COP trajectories. In order to evaluate dynamic balance ability, the COM-COP inclination angle, COM-COP inclination angular velocity and normalised COM-COP inclination angular jerk were used. Professional golfer group revealed a smaller COM-COP inclination angle and angular velocity than novice golfer group in the lead/trail direction (P < 0.01). In the normalised COM-COP inclination angular jerk, the professional golfer group showed a lower value than the other two groups in all directions. Professional golfers tend to exhibit improved dynamic balance, and this can be attributed to the neuromusculoskeletal system that maintains balance with proper postural control. This study has the potential to allow for an evaluation of the dynamic balance mechanism and will provide useful basic information for swing training and prevention of golf injuries.

  19. Comparison of the complete sequences of three different isolates of Pepino mosaic virus: size variability of the TGBp3 protein between tomato and L. peruvianum isolates.

    PubMed

    López, C; Soler, S; Nuez, F

    2005-03-01

    The complete nucleotide sequence of the genomes of two Spanish isolates (LE-2000 and LE-2002) from tomato and one Peruvian isolate (LP-2001) from Lycopersicon peruvianum of the Pepino mosaic virus (PepMV) were determined. The tomato isolates share identities higher than 99%, while the genome of LP-2001 had mean nucleotide identities of 95.6% to 96.0% with tomato isolates. The predicted amino acid sequences showed similarities ranging between 95.2% and 100% with TGBp3 and TGBp2 and CP proteins, respectively. In LP-2001 two main differences were found with respect to the tomato isolates; (i) the 5' untranslated region (UTR) was 2 nt shorter by deletion at position 12-13 and it had some polymorphims at the putative promoter sequence reported for PepMV tomato isolates and other potexviruses, which could be functionally significant for RNA replication, and (ii) the TGBp3 protein had two extra amino acids in the C-terminal region.

  20. Loop quantum cosmology gravitational baryogenesis

    NASA Astrophysics Data System (ADS)

    Odintsov, S. D.; Oikonomou, V. K.

    2016-11-01

    Loop quantum cosmology is an appealing quantum completion of classical cosmology, which brings along various theoretical features which in many cases offer a remedy for or modify various classical cosmology aspects. In this paper we address the gravitational baryogenesis mechanism in the context of loop quantum cosmology. As we demonstrate, when loop quantum cosmology effects are taken into account in the resulting Friedmann equations for a flat Friedmann-Robertson-Walker Universe, then even for a radiation-dominated Universe, the predicted baryon-to-entropy ratio from the gravitational baryogenesis mechanism is non-zero, in contrast to the Einstein-Hilbert case, in which case the baryon-to-entropy ratio is zero. We also discuss various other cases apart from the radiation domination case, and we discuss how the baryon-to-entropy ratio is affected from the parameters of the quantum theory. In addition, we use illustrative exact solutions of loop quantum cosmology and we investigate under which circumstances the baryon-to-entropy ratio can be compatible with the observational constraints.

  1. Higgs boson mass in the standard model at two-loop order and beyond

    SciTech Connect

    Martin, Stephen P.; Robertson, David G.

    2014-10-01

    We calculate the mass of the Higgs boson in the standard model in terms of the underlying Lagrangian parameters at complete 2-loop order with leading 3-loop corrections. A computer program implementing the results is provided. The program also computes and minimizes the standard model effective potential in Landau gauge at 2-loop order with leading 3-loop corrections.

  2. Complete prewetting

    NASA Astrophysics Data System (ADS)

    Yatsyshin, P.; Parry, A. O.; Kalliadasis, S.

    2016-07-01

    We study continuous interfacial transitions, analagous to two-dimensional complete wetting, associated with the first-order prewetting line, which can occur on steps, patterned walls, grooves and wedges, and which are sensitive to both the range of the intermolecular forces and interfacial fluctuation effects. These transitions compete with wetting, filling and condensation producing very rich phase diagrams even for relatively simple prototypical geometries. Using microscopic classical density functional theory to model systems with realistic Lennard-Jones fluid-fluid and fluid-substrate intermolecular potentials, we compute mean-field fluid density profiles, adsorption isotherms and phase diagrams for a variety of confining geometries.

  3. Loop-Extended Symbolic Execution on Binary Programs

    DTIC Science & Technology

    2009-03-02

    various program values in terms of four trip count sym- bolic variables TCi , one for each loop i in the program. For instance, the value of the...introduce a symbolic trip count variable TCi , which represents the number of times the loop (specifically, its back edge) has executed. The core of an...loop i, the domains for all the TCi variables in the abstract store are incremented from 0 to 1 and from ∗ to ∗ + 1. Such back edge values are then

  4. Completely bootstrapped tokamak

    SciTech Connect

    Weening, R.H. ); Boozer, A.H. )

    1992-01-01

    Numerical simulations of the evolution of large-scale magnetic fields have been developed using a mean-field Ohm's law. The Ohm's law is coupled to a {Delta}{prime} stabilty analysis and a magnetic island growth equation in order to simulate the behavior of tokamak plasmas that are subject to tearing modes. In one set of calculations, the magnetohydrodynamic (MHD)-stable regime of the tokamak is examined via the construction of an {ital l}{sub {ital i}} -{ital q}{sub {ital a}} diagram. The results confirm previous calculations that show that tearing modes introduce a stability boundary into the {ital l}{sub {ital i}} -{ital q}{sub {ital a}} space. In another series of simulations, the interaction between tearing modes and the bootstrap current is investigated. The results indicate that a completely bootstrapped tokamak may be possible, even in the absence of any externally applied loop voltage or current drive.

  5. Continuous control of phase-locked-loop bandwidth

    NASA Technical Reports Server (NTRS)

    Motal, G. W.; Vanelli, J. C.

    1980-01-01

    Tracking loop filter with continuous bandwidth control smooths transition from wide to narrow band. Circuit was designed for Space Shuttle where bandwidth varied between 320 Hz for acquisition and 20 Hz for tracking. Field-effect transitor (FET) acts as voltage controlled variable resistance, changing time constant of filter between phase detector and voltage-controlled oscillator in phase-locked loop.

  6. Multiprotein DNA Looping

    NASA Astrophysics Data System (ADS)

    Vilar, Jose M. G.; Saiz, Leonor

    2006-06-01

    DNA looping plays a fundamental role in a wide variety of biological processes, providing the backbone for long range interactions on DNA. Here we develop the first model for DNA looping by an arbitrarily large number of proteins and solve it analytically in the case of identical binding. We uncover a switchlike transition between looped and unlooped phases and identify the key parameters that control this transition. Our results establish the basis for the quantitative understanding of fundamental cellular processes like DNA recombination, gene silencing, and telomere maintenance.

  7. Introduction to Loop Heat Pipes

    NASA Technical Reports Server (NTRS)

    Ku, Jentung

    2015-01-01

    This is the presentation file for the short course Introduction to Loop Heat Pipes, to be conducted at the 2015 Thermal Fluids and Analysis Workshop, August 3-7, 2015, Silver Spring, Maryland. This course will discuss operating principles and performance characteristics of a loop heat pipe. Topics include: 1) pressure profiles in the loop; 2) loop operating temperature; 3) operating temperature control; 4) loop startup; 4) loop shutdown; 5) loop transient behaviors; 6) sizing of loop components and determination of fluid inventory; 7) analytical modeling; 8) examples of flight applications; and 9) recent LHP developments.

  8. Complete Makeover

    NASA Technical Reports Server (NTRS)

    2004-01-01

    [figure removed for brevity, see original site]

    Released July 23, 2004 The atmosphere of Mars is a dynamic system. Water-ice clouds, fog, and hazes can make imaging the surface from space difficult. Dust storms can grow from local disturbances to global sizes, through which imaging is impossible. Seasonal temperature changes are the usual drivers in cloud and dust storm development and growth.

    Eons of atmospheric dust storm activity has left its mark on the surface of Mars. Dust carried aloft by the wind has settled out on every available surface; sand dunes have been created and moved by centuries of wind; and the effect of continual sand-blasting has modified many regions of Mars, creating yardangs and other unusual surface forms.

    We finish our look at Mars's dynamic atmosphere with an image of the surface that has been completely modified by the wind. Even the small ridges that remain have been ground down to a cliff-face with a 'tail' of eroded material. The crosshatching shows that the wind regime has remained mainly E/W to ENE/WSW.

    Image information: VIS instrument. Latitude 8.9, Longitude 221 East (139 West). 19 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip

  9. A single-loop optimization method for reliability analysis with second order uncertainty

    NASA Astrophysics Data System (ADS)

    Xie, Shaojun; Pan, Baisong; Du, Xiaoping

    2015-08-01

    Reliability analysis may involve random variables and interval variables. In addition, some of the random variables may have interval distribution parameters owing to limited information. This kind of uncertainty is called second order uncertainty. This article develops an efficient reliability method for problems involving the three aforementioned types of uncertain input variables. The analysis produces the maximum and minimum reliability and is computationally demanding because two loops are needed: a reliability analysis loop with respect to random variables and an interval analysis loop for extreme responses with respect to interval variables. The first order reliability method and nonlinear optimization are used for the two loops, respectively. For computational efficiency, the two loops are combined into a single loop by treating the Karush-Kuhn-Tucker (KKT) optimal conditions of the interval analysis as constraints. Three examples are presented to demonstrate the proposed method.

  10. Explaining Warm Coronal Loops

    NASA Technical Reports Server (NTRS)

    Klimchuk, James A.; Karpen, Judy T.; Patsourakos, Spiros

    2008-01-01

    One of the great mysteries of coronal physics that has come to light in the last few years is the discovery that warn (- 1 INK) coronal loops are much denser than expected for quasi-static equilibrium. Both the excess densities and relatively long lifetimes of the loops can be explained with bundles of unresolved strands that are heated impulsively to very high temperatures. Since neighboring strands are at different stages of cooling, the composite loop bundle is multi-thermal, with the distribution of temperatures depending on the details of the "nanoflare storm." Emission hotter than 2 MK is predicted, but it is not clear that such emission is always observed. We consider two possible explanations for the existence of over-dense warm loops without corresponding hot emission: (1) loops are bundles of nanoflare heated strands, but a significant fraction of the nanoflare energy takes the form of a nonthermal electron beam rather then direct plasma heating; (2) loops are bundles of strands that undergo thermal nonequilibrium that results when steady heating is sufficiently concentrated near the footpoints. We present numerical hydro simulations of both of these possibilities and explore the observational consequences, including the production of hard X-ray emission and absorption by cool material in the corona.

  11. Toward loop quantization of plane gravitational waves

    NASA Astrophysics Data System (ADS)

    Hinterleitner, Franz; Major, Seth

    2012-03-01

    The polarized Gowdy model in terms of Ashtekar-Barbero variables is reduced with an additional constraint derived from the Killing equations for plane gravitational waves with parallel rays. The new constraint is formulated in a diffeomorphism invariant manner and, when it is included in the model, the resulting constraint algebra is first class, in contrast to the prior work done in special coordinates. Using an earlier work by Banerjee and Date, the constraints are expressed in terms of classical quantities that have an operator equivalent in loop quantum gravity, making these plane gravitational wave spacetimes accessible to loop quantization techniques.

  12. Giant Magnetic Loop Sweeps Through Space Between Stellar Pair

    NASA Astrophysics Data System (ADS)

    2010-01-01

    Astronomers have found a giant magnetic loop stretched outward from one of the stars making up the famous double-star system Algol. The scientists used an international collection of radio telescopes to discover the feature, which may help explain details of previous observations of the stellar system. "This is the first time we've seen a feature like this in the magnetic field of any star other than the Sun," said William Peterson, of the University of Iowa. The pair, 93 light-years from Earth, includes a star about 3 times more massive than the Sun and a less-massive companion, orbiting it at a distance of 5.8 million miles, only about six percent of the distance between Earth and the Sun. The newly-discovered magnetic loop emerges from the poles of the less-massive star and stretches outward in the direction of the primary star. As the secondary star orbits its companion, one side -- the side with the magnetic loop -- constantly faces the more-massive star, just as the same side of our Moon always faces the Earth. The scientists detected the magnetic loop by making extremely detailed images of the system using an intercontinental set of radio telescopes, including the National Science Foundation's Very Long Baseline Array, Very Large Array, and Robert C. Byrd Green Bank Telescope, along with the Effelsberg radio telescope in Germany. These radio telescopes were used as a single observing system that offered both great detail, or resolving power, and high sensitivity to detect very faint radio waves. When working together, these telescopes are known as the High Sensitivity Array. Algol, in the constellation Perseus, is visible to the naked eye and well-known to amateur astronomers. As seen from Earth, the two stars regularly pass in front of each other, causing a notable change in brightness. The pair completes a cycle of such eclipses in less than three days, making it a popular object for amateur observers. The variability in brightness was discovered by an

  13. Smart feedback loops

    NASA Astrophysics Data System (ADS)

    Chepurnov, A. S.; Gribov, I. V.; Gudkov, K. A.; Shumakov, A. V.; Shvedunov, V. I.

    1994-12-01

    It is necessary to find the golden mean in allocating the processing resources of a computer control system. Traditionally, feedback loops operate at the lower levels to ensure safe and stable operation of the accelerator. At present we use analogue and digital feedback loops. Some systems, such as the RF, require more complex algorithms. A possible way of providing these, using digital signal processors is described. The results of tests with the Race-Track Microtron Linac are given and the sources of the main internal and external disturbances have been analysed.

  14. Concentric Loop Surface Coil

    NASA Astrophysics Data System (ADS)

    Hernández-Flores, R.; Rodríguez-González, A. O.; Salgado-Lujambio, P.; Barrios-Alvarez, F. A.

    2002-08-01

    A surface coil for MRI consisted of two concentric loops was developed for brain imaging. Prior to build the coil prototype, the magnetic field (B1) generated by the coil was numerically simulated. This field simulation is based on the Biot-Savart law for the circular- and square-shaped loops. From these theoretical results, we can appreciate an improvement on the B1 homogeneity. Brain images obtained at 1.5 Tesla show a good sensitivity in a particular region of interest. Also, these images compared well against images obtained with a circular-shaped coil. This receiver coil can generate high quality brain images.

  15. Wilson-loop instantons

    NASA Technical Reports Server (NTRS)

    Lee, Kimyeong; Holman, Richard; Kolb, Edward W.

    1987-01-01

    Wilson-loop symmetry breaking is considered on a space-time of the form M4 x K, where M4 is a four-dimensional space-time and K is an internal space with nontrivial and finite fundamental group. It is shown in a simple model that the different vacua obtained by breaking a non-Abelian gauge group by Wilson loops are separated in the space of gauge potentials by a finite energy barrier. An interpolating gauge configuration is then constructed between these vacua and shown to have minimum energy. Finally some implications of this construction are discussed.

  16. Hybrid Combustion-Gasification Chemical Looping

    SciTech Connect

    Herbert Andrus; Gregory Burns; John Chiu; Gregory Lijedahl; Peter Stromberg; Paul Thibeault

    2009-01-07

    For the past several years Alstom Power Inc. (Alstom), a leading world-wide power system manufacturer and supplier, has been in the initial stages of developing an entirely new, ultra-clean, low cost, high efficiency power plant for the global power market. This new power plant concept is based on a hybrid combustion-gasification process utilizing high temperature chemical and thermal looping technology The process consists of the oxidation, reduction, carbonation, and calcination of calcium-based compounds, which chemically react with coal, biomass, or opportunity fuels in two chemical loops and one thermal loop. The chemical and thermal looping technology can be alternatively configured as (i) a combustion-based steam power plant with CO{sub 2} capture, (ii) a hybrid combustion-gasification process producing a syngas for gas turbines or fuel cells, or (iii) an integrated hybrid combustion-gasification process producing hydrogen for gas turbines, fuel cells or other hydrogen based applications while also producing a separate stream of CO{sub 2} for use or sequestration. In its most advanced configuration, this new concept offers the promise to become the technology link from today's Rankine cycle steam power plants to tomorrow's advanced energy plants. The objective of this work is to develop and verify the high temperature chemical and thermal looping process concept at a small-scale pilot facility in order to enable AL to design, construct and demonstrate a pre-commercial, prototype version of this advanced system. In support of this objective, Alstom and DOE started a multi-year program, under this contract. Before the contract started, in a preliminary phase (Phase 0) Alstom funded and built the required small-scale pilot facility (Process Development Unit, PDU) at its Power Plant Laboratories in Windsor, Connecticut. Construction was completed in calendar year 2003. The objective for Phase I was to develop the indirect combustion loop with CO{sub 2

  17. ABJ Wilson loops and Seiberg duality

    NASA Astrophysics Data System (ADS)

    Shinji, Hirano; Keita, Nii; Masaki, Shigemori

    2014-11-01

    We study supersymmetric Wilson loops in the {N} = 6 supersymmetric U(N_1)_k × U(N_2)_{-k} Chern-Simons-matter (CSM) theory, the ABJ theory, at finite N_1, N_2, and k. This generalizes our previous study on the ABJ partition function. First computing the Wilson loops in the U(N_1) × U(N_2) lens space matrix model exactly, we perform an analytic continuation, N_2 to -N_2, to obtain the Wilson loops in the ABJ theory that is given in terms of a formal series and is only valid in perturbation theory. Via a Sommerfeld-Watson-type transform, we provide a nonperturbative completion that renders the formal series well defined at all couplings. This is given by min (N_1,N_2)-dimensional integrals that generalize the “mirror description” of the partition function of the ABJM theory. Using our results, we find the maps between the Wilson loops in the original and Seiberg dual theories and prove the duality. In our approach we can explicitly see how the perturbative and nonperturbative contributions to the Wilson loops are exchanged under the duality. The duality maps are further supported by a heuristic yet very useful argument based on the brane configuration as well as an alternative derivation based on that of Kapustin and Willett (arXiv:1302.2164 [hep-th]).

  18. Livermore Compiler Analysis Loop Suite

    SciTech Connect

    Hornung, R. D.

    2013-03-01

    LCALS is designed to evaluate compiler optimizations and performance of a variety of loop kernels and loop traversal software constructs. Some of the loop kernels are pulled directly from "Livermore Loops Coded in C", developed at LLNL (see item 11 below for details of earlier code versions). The older suites were used to evaluate floating-point performances of hardware platforms prior to porting larger application codes. The LCALS suite is geared toward assissing C++ compiler optimizations and platform performance related to SIMD vectorization, OpenMP threading, and advanced C++ language features. LCALS contains 20 of 24 loop kernels from the older Livermore Loop suites, plus various others representative of loops found in current production appkication codes at LLNL. The latter loops emphasize more diverse loop constructs and data access patterns than the others, such as multi-dimensional difference stencils. The loops are included in a configurable framework, which allows control of compilation, loop sampling for execution timing, which loops are run and their lengths. It generates timing statistics for analysis and comparing variants of individual loops. Also, it is easy to add loops to the suite as desired.

  19. NETL - Chemical Looping Reactor

    SciTech Connect

    2013-07-24

    NETL's Chemical Looping Reactor unit is a high-temperature integrated CLC process with extensive instrumentation to improve computational simulations. A non-reacting test unit is also used to study solids flow at ambient temperature. The CLR unit circulates approximately 1,000 pounds per hour at temperatures around 1,800 degrees Fahrenheit.

  20. Closing the Loop Sampler.

    ERIC Educational Resources Information Center

    California Integrated Waste Management Board, Sacramento.

    Closing the Loop (CTL) is a science curriculum designed to introduce students to integrated waste management through awareness. This document presents five lesson plans focusing on developing an understanding of natural resources, solid wastes, conservation, and the life of landfills. Contents include: (1) "What Are Natural Resources?"; (2)…

  1. NETL - Chemical Looping Reactor

    ScienceCinema

    None

    2016-07-12

    NETL's Chemical Looping Reactor unit is a high-temperature integrated CLC process with extensive instrumentation to improve computational simulations. A non-reacting test unit is also used to study solids flow at ambient temperature. The CLR unit circulates approximately 1,000 pounds per hour at temperatures around 1,800 degrees Fahrenheit.

  2. The Energy Landscape of Hyperstable LacI-DNA Loops

    NASA Astrophysics Data System (ADS)

    Kahn, Jason

    2009-03-01

    The Escherichia coli LacI protein represses transcription of the lac operon by blocking access to the promoter through binding at a promoter-proximal DNA operator. The affinity of tetrameric LacI (and therefore the repression efficiency) is enhanced by simultaneous binding to an auxiliary operator, forming a DNA loop. Hyperstable LacI-DNA loops were previously shown to be formed on DNA constructs that include a sequence-directed bend flanked by operators. Biochemical experiments showed that two such constructs (9C14 and 11C12) with different helical phasing between the operators and the DNA bend form different DNA loop shapes. The geometry and topology of the loops and the relevance of alternative conformations suggested by probable flexible linkers in LacI remain unclear. Bulk and single molecule fluorescence resonance energy transfer (SM-FRET, with D. English) experiments on a dual fluorophore-labeled 9C14-LacI loop demonstrate that it adopts a single, stable, rigid closed-form loop conformation. Here, we characterize the LacI-9C14 loop by SM-FRET as a function of inducer isopropyl-β,D-thiogalactoside (IPTG) concentration. Energy transfer measurements reveal partial but incomplete destabilization of loop formation by IPTG. Surprisingly, there is no change in the energy transfer efficiency of the remaining looped population. Models for the regulation of the lac operon often assume complete disruption of LacI-operator complexes upon inducer binding to LacI. Our work shows that even at saturating IPTG there is still a significant population of LacI-DNA complexes in a looped state, in accord with previous in vivo experiments that show incomplete induction (with J. Maher). Finally, we will report progress on characterizing the ``energy landscape'' for DNA looping upon systematic variation of the DNA linkers between the operators and the bending locus. Rod mechanics simulations (with N. Perkins) provide testable predictions on loop stability, topology, and FRET.

  3. Closed-Loop Endoatmospheric Ascent Guidance

    NASA Technical Reports Server (NTRS)

    Lu, Ping; Sun, Hongsheng; Jackson, Scott (Technical Monitor)

    2002-01-01

    This paper will present a complete formulation of the optimal control problem for atmospheric ascent of rocket powered launch vehicles subject to usual load constraints and final condition constraints. We shall demonstrate that the classical finite difference method for two-point-boundary-value-problems (TPBVP) is suited for solving the ascent trajectory optimization problem in real time, therefore closed-loop optimal endoatmospheric ascent guidance becomes feasible. Numerical simulations with a the vehicle data of a reusable launch vehicle will be provided.

  4. Loop Heat Pipes and Capillary Pumped Loops: An Applications Perspective

    NASA Technical Reports Server (NTRS)

    Butler, Dan; Ku, Jentung; Swanson, Theodore; Obenschain, Arthur F. (Technical Monitor)

    2001-01-01

    Capillary pumped loops (CPLS) and loop heat pipes (LHPS) are versatile two-phase heat transfer devices which have recently gained increasing acceptance in space applications. Both systems work based on the same principles and have very similar designs. Nevertheless, some differences exist in the construction of the evaporator and the hydro-accumulator, and these differences lead to very distinct operating characteristics for each loop. This paper presents comparisons of the two loops from an applications perspective, and addresses their impact on spacecraft design, integration, and test. Some technical challenges and issues for both loops are also addressed.

  5. Coronal Loops: Evolving Beyond the Isothermal Approximation

    NASA Astrophysics Data System (ADS)

    Schmelz, J. T.; Cirtain, J. W.; Allen, J. D.

    2002-05-01

    Are coronal loops isothermal? A controversy over this question has arisen recently because different investigators using different techniques have obtained very different answers. Analysis of SOHO-EIT and TRACE data using narrowband filter ratios to obtain temperature maps has produced several key publications that suggest that coronal loops may be isothermal. We have constructed a multi-thermal distribution for several pixels along a relatively isolated coronal loop on the southwest limb of the solar disk using spectral line data from SOHO-CDS taken on 1998 Apr 20. These distributions are clearly inconsistent with isothermal plasma along either the line of sight or the length of the loop, and suggested rather that the temperature increases from the footpoints to the loop top. We speculated originally that these differences could be attributed to pixel size -- CDS pixels are larger, and more `contaminating' material would be expected along the line of sight. To test this idea, we used CDS iron line ratios from our data set to mimic the isothermal results from the narrowband filter instruments. These ratios indicated that the temperature gradient along the loop was flat, despite the fact that a more complete analysis of the same data showed this result to be false! The CDS pixel size was not the cause of the discrepancy; rather, the problem lies with the isothermal approximation used in EIT and TRACE analysis. These results should serve as a strong warning to anyone using this simplistic method to obtain temperature. This warning is echoed on the EIT web page: ``Danger! Enter at your own risk!'' In other words, values for temperature may be found, but they may have nothing to do with physical reality. Solar physics research at the University of Memphis is supported by NASA grant NAG5-9783. This research was funded in part by the NASA/TRACE MODA grant for Montana State University.

  6. Aurora Australis, Sinuous Loop

    NASA Technical Reports Server (NTRS)

    1991-01-01

    This view of the Aurora Australis or Southern Lights (location unknown) shows a sinuous looping band of airglow above the Earth Limb. Calculated to be in the 80 - 120 km altitude region, auroral activity is due to exitation of atomic oxygen in the upper atmosphere by radiation from the van Allen Radiation Belts and is most common above the 65 degree north and south latitude range during the spring and fall of the year.

  7. Loop Quantum Cosmology.

    PubMed

    Bojowald, Martin

    2005-01-01

    Quantum gravity is expected to be necessary in order to understand situations where classical general relativity breaks down. In particular in cosmology one has to deal with initial singularities, i.e., the fact that the backward evolution of a classical space-time inevitably comes to an end after a finite amount of proper time. This presents a breakdown of the classical picture and requires an extended theory for a meaningful description. Since small length scales and high curvatures are involved, quantum effects must play a role. Not only the singularity itself but also the surrounding space-time is then modified. One particular realization is loop quantum cosmology, an application of loop quantum gravity to homogeneous systems, which removes classical singularities. Its implications can be studied at different levels. Main effects are introduced into effective classical equations which allow to avoid interpretational problems of quantum theory. They give rise to new kinds of early universe phenomenology with applications to inflation and cyclic models. To resolve classical singularities and to understand the structure of geometry around them, the quantum description is necessary. Classical evolution is then replaced by a difference equation for a wave function which allows to extend space-time beyond classical singularities. One main question is how these homogeneous scenarios are related to full loop quantum gravity, which can be dealt with at the level of distributional symmetric states. Finally, the new structure of space-time arising in loop quantum gravity and its application to cosmology sheds new light on more general issues such as time.

  8. Loop Quantum Cosmology.

    PubMed

    Bojowald, Martin

    2008-01-01

    Quantum gravity is expected to be necessary in order to understand situations in which classical general relativity breaks down. In particular in cosmology one has to deal with initial singularities, i.e., the fact that the backward evolution of a classical spacetime inevitably comes to an end after a finite amount of proper time. This presents a breakdown of the classical picture and requires an extended theory for a meaningful description. Since small length scales and high curvatures are involved, quantum effects must play a role. Not only the singularity itself but also the surrounding spacetime is then modified. One particular theory is loop quantum cosmology, an application of loop quantum gravity to homogeneous systems, which removes classical singularities. Its implications can be studied at different levels. The main effects are introduced into effective classical equations, which allow one to avoid the interpretational problems of quantum theory. They give rise to new kinds of early-universe phenomenology with applications to inflation and cyclic models. To resolve classical singularities and to understand the structure of geometry around them, the quantum description is necessary. Classical evolution is then replaced by a difference equation for a wave function, which allows an extension of quantum spacetime beyond classical singularities. One main question is how these homogeneous scenarios are related to full loop quantum gravity, which can be dealt with at the level of distributional symmetric states. Finally, the new structure of spacetime arising in loop quantum gravity and its application to cosmology sheds light on more general issues, such as the nature of time.

  9. Loops of Jupiter

    NASA Astrophysics Data System (ADS)

    Opolski, Antoni

    2014-12-01

    Professor Antoni Opolski was actively interested in astronomy after his retirement in 1983. He especially liked to study the works of the famous astronomer Copernicus getting inspiration for his own work. Opolski started his work on planetary loops in 2011 continuing it to the end of 2012 . During this period calculations, drawings, tables, and basic descriptions of all the planets of the Solar System were created with the use of a piece of paper and a pencil only. In 2011 Antoni Opolski asked us to help him in editing the manuscript and preparing it for publication. We have been honored having the opportunity to work on articles on planetary loops with Antoni Opolski in his house for several months. In the middle of 2012 the detailed material on Jupiter was ready. However, professor Opolski improved the article by smoothing the text and preparing new, better drawings. Finally the article ''Loops of Jupiter'', written by the 99- year old astronomer, was published in the year of his 100th birthday.

  10. Verification of Loop Diagnostics

    NASA Technical Reports Server (NTRS)

    Winebarger, A.; Lionello, R.; Mok, Y.; Linker, J.; Mikic, Z.

    2014-01-01

    Many different techniques have been used to characterize the plasma in the solar corona: density-sensitive spectral line ratios are used to infer the density, the evolution of coronal structures in different passbands is used to infer the temperature evolution, and the simultaneous intensities measured in multiple passbands are used to determine the emission measure. All these analysis techniques assume that the intensity of the structures can be isolated through background subtraction. In this paper, we use simulated observations from a 3D hydrodynamic simulation of a coronal active region to verify these diagnostics. The density and temperature from the simulation are used to generate images in several passbands and spectral lines. We identify loop structures in the simulated images and calculate the loop background. We then determine the density, temperature and emission measure distribution as a function of time from the observations and compare with the true temperature and density of the loop. We find that the overall characteristics of the temperature, density, and emission measure are recovered by the analysis methods, but the details of the true temperature and density are not. For instance, the emission measure curves calculated from the simulated observations are much broader than the true emission measure distribution, though the average temperature evolution is similar. These differences are due, in part, to inadequate background subtraction, but also indicate a limitation of the analysis methods.

  11. Chemical Looping Combustion Kinetics

    SciTech Connect

    Edward Eyring; Gabor Konya

    2009-03-31

    One of the most promising methods of capturing CO{sub 2} emitted by coal-fired power plants for subsequent sequestration is chemical looping combustion (CLC). A powdered metal oxide such as NiO transfers oxygen directly to a fuel in a fuel reactor at high temperatures with no air present. Heat, water, and CO{sub 2} are released, and after H{sub 2}O condensation the CO{sub 2} (undiluted by N{sub 2}) is ready for sequestration, whereas the nickel metal is ready for reoxidation in the air reactor. In principle, these processes can be repeated endlessly with the original nickel metal/nickel oxide participating in a loop that admits fuel and rejects ash, heat, and water. Our project accumulated kinetic rate data at high temperatures and elevated pressures for the metal oxide reduction step and for the metal reoxidation step. These data will be used in computational modeling of CLC on the laboratory scale and presumably later on the plant scale. The oxygen carrier on which the research at Utah is focused is CuO/Cu{sub 2}O rather than nickel oxide because the copper system lends itself to use with solid fuels in an alternative to CLC called 'chemical looping with oxygen uncoupling' (CLOU).

  12. ac power control in the Core Flow Test Loop

    SciTech Connect

    McDonald, D.W.

    1980-01-01

    This work represents a status report on a development effort to design an ac power controller for the Core Flow Test Loop. The Core Flow Test Loop will be an engineering test facility which will simulate the thermal environment of a gas-cooled fast-breeder reactor. The problems and limitations of using sinusoidal ac power to simulate the power generated within a nuclear reactor are addressed. The transformer-thyristor configuration chosen for the Core Flow Test Loop power supply is presented. The initial considerations, design, and analysis of a closed-loop controller prototype are detailed. The design is then analyzed for improved performance possibilities and failure modes are investigated at length. A summary of the work completed to date and a proposed outline for continued development completes the report.

  13. The Evolution of Transition Region Loops Using IRIS and AIA

    NASA Technical Reports Server (NTRS)

    Winebarger, Amy R.; DePontieu, Bart

    2014-01-01

    Over the past 50 years, the model for the structure of the solar transition region has evolved from a simple transition layer between the cooler chromosphere to the hotter corona to a complex and diverse region that is dominated by complete loops that never reach coronal temperatures. The IRIS slitjaw images show many complete transition region loops. Several of the "coronal" channels in the SDO AIA instrument include contributions from weak transition region lines. In this work, we combine slitjaw images from IRIS with these channels to determine the evolution of the loops. We develop a simple model for the temperature and density evolution of the loops that can explain the simultaneous observations. Finally, we estimate the percentage of AIA emission that originates in the transition region.

  14. Extension of Loop Quantum Gravity to f(R) Theories

    NASA Astrophysics Data System (ADS)

    Zhang, Xiangdong; Ma, Yongge

    2011-04-01

    The four-dimensional metric f(R) theories of gravity are cast into connection-dynamical formalism with real su(2) connections as configuration variables. Through this formalism, the classical metric f(R) theories are quantized by extending the loop quantization scheme of general relativity. Our results imply that the nonperturbative quantization procedure of loop quantum gravity is valid not only for general relativity but also for a rather general class of four-dimensional metric theories of gravity.

  15. Extension of loop quantum gravity to f(R) theories.

    PubMed

    Zhang, Xiangdong; Ma, Yongge

    2011-04-29

    The four-dimensional metric f(R) theories of gravity are cast into connection-dynamical formalism with real su(2) connections as configuration variables. Through this formalism, the classical metric f(R) theories are quantized by extending the loop quantization scheme of general relativity. Our results imply that the nonperturbative quantization procedure of loop quantum gravity is valid not only for general relativity but also for a rather general class of four-dimensional metric theories of gravity.

  16. Recent progress in one-loop multi-parton calculations

    SciTech Connect

    Bern, Z.; Dixon, L.; Dunbar, D.C.; Kosower, D.A.

    1994-09-01

    The authors describe techniques that simplify the calculation of one-loop QCD amplitudes with many external legs, which are needed for next-to-leading-order (NLO) corrections to multi-jet processes. The constraints imposed by perturbative unitarity, collinear singularities and a supersymmetry-inspired organization of helicity amplitudes are particularly useful. Certain sequences of one-loop helicity amplitudes may be obtained for an arbitrary number of external gluons using these techniques. They also report on progress in completing the set of one-loop helicity amplitudes required for NLO three-jet production at hadron colliders, namely the amplitudes with two external quarks and three gluons.

  17. Transverse Oscillations in a Coronal Loop Triggered by a Jet

    NASA Astrophysics Data System (ADS)

    Sarkar, S.; Pant, V.; Srivastava, A. K.; Banerjee, D.

    2016-11-01

    We detect and analyse transverse oscillations in a coronal loop, lying at the south-east limb of the Sun as seen from the Atmospheric Imaging Assembly (AIA) onboard the Solar Dynamics Observatory (SDO). The jet is believed to trigger transverse oscillations in the coronal loop. The jet originates from a region close to the coronal loop on 19 September 2014 at 02:01:35 UT. The length of the loop is estimated to be between 377 - 539 Mm. Only one complete oscillation is detected with an average period of about 32±5 min. Using magnetohydrodynamic (MHD) seismologic inversion techniques, we estimate the magnetic field inside the coronal loop to be between 2.68 - 4.5 G. The velocity of the hot and cool components of the jet is estimated to be 168 km s^{-1} and 43 km s^{-1}, respectively. The energy density of the jet is found to be greater than the energy density of the oscillating coronal loop. We therefore conclude that the jet triggered transverse oscillations in the coronal loop. To our knowledge, this is the first coronal loop seismology study using the properties of a jet propagation to trigger oscillations.

  18. Optical parametric loop mirror

    NASA Astrophysics Data System (ADS)

    Mori, K.; Morioka, T.; Saruwatari, M.

    1995-06-01

    A novel configuration for four-wave mixing (FWM) is proposed that offers the remarkable feature of inherently separating the FWM wave from the input pump and signal waves and suppressing their background amplified stimulated emission without optical filtering. In the proposed configuration, an optical parametric loop mirror, two counterpropagating FWM waves generated in a Sagnac interferometer interfere with a relative phase difference that is introduced deliberately. FWM frequency-conversion experiments in a polarization-maintaining fiber achieved more than 35 dB of input-wave suppression against the FWM wave.

  19. Closing the loop.

    PubMed

    Dassau, E; Atlas, E; Phillip, M

    2011-02-01

    Closed-loop algorithms can be found in every aspect of everyday modern life. Automation and control are used constantly to provide safety and to improve quality of life. Closed-loop systems and algorithms can be found in home appliances, automobiles, aviation and more. Can one imagine nowadays driving a car without ABS, cruise control or even anti-sliding control? Similar principles of automation and control can be used in the management of diabetes mellitus (DM). The idea of an algorithmic/technological way to control glycaemia is not new and has been researched for more than four decades. However, recent improvements in both glucose-sensing technology and insulin delivery together with advanced control and systems engineering made this dream of an artificial pancreas possible. The artificial pancreas may be the next big step in the treatment of DM since the use of insulin analogues. An artificial pancreas can be described as internal or external devices that use continuous glucose measurements to automatically manage exogenous insulin delivery with or without other hormones in an attempt to restore glucose regulation in individuals with DM using a control algorithm. This device as described can be internal or external; can use different types of control algorithms with bi-hormonal or uni-hormonal design; and can utilise different ways to administer them. The different designs and implementations have transitioned recently from in silico simulations to clinical evaluation stage with practical applications in mind. This may mark the beginning of a new era in diabetes management with the introduction of semi-closed-loop systems that can prevent or minimise nocturnal hypoglycaemia, to hybrid systems that will manage blood glucose (BG) levels with minimal user intervention to finally fully automated systems that will take the user out of the loop. More and more clinical trials will be needed for the artificial pancreas to become a reality but initial encouraging

  20. Genetic variability and discrimination of low doses of Toxocara spp. from public areas soil inferred by loop-mediated isothermal amplification assay as a field-friendly molecular tool

    PubMed Central

    Ozlati, Maryam; Spotin, Adel; Shahbazi, Abbas; Mahami-Oskouei, Mahmoud; Hazratian, Teimour; Adibpor, Mohammad; Ahmadpour, Ehsan; Dolatkhah, Afsaneh; Khoshakhlagh, Paria

    2016-01-01

    Abstract: Aim: One of the main diagnostic problems of conventional polymerase chain reaction (PCR) is indiscrimination of low parasitic loads in soil samples. The aim of this study is to determine the genetic diversity and identification of Toxocara spp. from public areas soil inferred by loop-mediated isothermal amplification (LAMP) assay. Materials and Methods: A total of 180 soil samples were collected from various streets and public parks of northwest Iran. The DNA of recovered Toxocara eggs were extracted and amplified by PCR and LAMP following ZnSO4 flotation technique. The amplicons of internal transcribed spacer-2 gene were sequenced to reveal the heterogeneity traits of Toxocara spp. In addition, Toxocara canis sequences of southwest Iran were directly retrieved to compare gene flow between two distinct populations. Results: Toxocara spp. eggs were found in 57, 14 and 77 of soil samples using the microscopy, PCR and LAMP (detection limit 1-3 eggs/200 g soil), respectively. 7.7% of isolates were identified as T. canis by PCR method, while LAMP was able to detect 27.2%, 15.5% and 12.2% as Toxocara cati, T. canis and mixed infections, respectively. The kappa coefficient between LAMP and microscopy indicated a strong agreement (0.765) but indicated a faint agreement among LAMP-PCR (0.203) and PCR-microscopy (0.308) methods. A pairwise fixation index (Fst) as a degree of gene flow was generally low (0.02156) among Toxocara populations of northwest and southwest Iran. Conclusions: The statistically significant Fst value indicates that the T. canis populations are not genetically well differentiated between northwest and southwest Iran. This shows that here is possibly an epidemiological drift due to the transfer of alleles. The LAMP assay because of its shorter reaction time, more sensitivity, and simultaneous detection of environmental contamination to be appears as valuable field diagnosis compared to PCR. Therefore, the detection of low Toxocara spp. loads

  1. Constructing QCD one-loop amplitudes

    SciTech Connect

    Forde, Darren; /SLAC /UCLA

    2008-02-22

    In the context of constructing one-loop amplitudes using a unitarity bootstrap approach we discuss a general systematic procedure for obtaining the coefficients of the scalar bubble and triangle integral functions of one-loop amplitudes. Coefficients are extracted after examining the behavior of the cut integrand as the unconstrained parameters of a specifically chosen parameterization of the cut loop momentum approach infinity. Measurements of new physics at the forthcoming experimental program at CERN's Large Hadron Collider (LHC) will require a precise understanding of processes at next-to-leading order (NLO). This places increased demands for the computation of new one-loop amplitudes. This in turn has spurred recent developments towards improved calculational techniques. Direct calculations using Feynman diagrams are in general inefficient. Developments of more efficient techniques have usually centered around unitarity techniques [1], where tree amplitudes are effectively 'glued' together to form loops. The most straightforward application of this method, in which the cut loop momentum is in D = 4, allows for the computation of 'cut-constructible' terms only, i.e. (poly)logarithmic containing terms and any related constants. QCD amplitudes contain, in addition to such terms, rational pieces which cannot be derived using such cuts. These 'missing' rational parts can be extracted using cut loop momenta in D = 4-2 {var_epsilon}. The greater difficulty of such calculations has restricted the application of this approach, although recent developments [3, 4] have provided new promise for this technique. Recently the application of on-shell recursion relations [5] to obtaining the 'missing' rational parts of one-loop processes [6] has provided an alternative very promising solution to this problem. In combination with unitarity methods an 'on-shell bootstrap' approach provides an efficient technique for computing complete one-loop QCD amplitudes [7]. Additionally

  2. Closing the loop with blur

    NASA Astrophysics Data System (ADS)

    Tani, Jacopo

    A great variety of systems use image sensors to provide measurements for closed loop operation. A drawback of using image sensors in real-time feedback is that they provide measurements at slower sampling rates as compared to the actuators, typically around 30 Hz for CCD cameras, hence acting as the bottleneck for closed loop control bandwidths. While high speed cameras exist, higher frame rates imply an upper bound on exposures which lowers the signal-to-noise-ratio (SNR), reducing measurements accuracy. The integrative nature of image sensors though offers the opportunity to prolong the exposure window and collect motion blurred measurements. This research describes how to exploit the dynamic information of observed system outputs, encoded in motion blur, to control fast systems at the fast rate through slow rate image sensors. In order to achieve this objective it is necessary to (a) design a controller providing fast rate input to the system based on the slow image measurements. Ideally such a controller would require a fast rate estimate of the system's state variables in order to provide the necessary control action, therefore an (b) image blur based estimator is to be developed. State estimators typically need a model of the system in order to provide their estimates, so (c) a system identification problem has to be addressed, where a reliable model describing the frequency content of the system, up to frequencies corresponding to the fast rate, has to be determined through slow rate image sensor measurements. Alternatively when such a procedure is not possible for lack, e.g., of knowledge of the input to the system, then (d) a method to reconstruct the output signal frequency content up to frequencies above those set by the limitations of the sampling theorem is to be devised. Therefore in order to "close the loop with blur", this work describes how to pose and solve the problems of, namely: system identification , state estimation, closed loop control and

  3. Loop quantum f(R) theories

    NASA Astrophysics Data System (ADS)

    Zhang, Xiangdong; Ma, Yongge

    2011-09-01

    As modified gravity theories, the four-dimensional metric f(R) theories are cast into connection-dynamical formalism with real su(2) connections as configuration variables. This formalism enables us to extend the nonperturbative loop quantization scheme of general relativity to any metric f(R) theories. The quantum kinematical framework of f(R) gravity is rigorously constructed, where the quantum dynamics can be launched. Both Hamiltonian constraint operator and master constraint operator for f(R) theories are well defined. Our results show that the nonperturbative quantization procedure of loop quantum gravity are valid not only for general relativity but also for a rather general class of four-dimensional metric theories of gravity.

  4. Loop expansion and the bosonic representation of loop quantum gravity

    NASA Astrophysics Data System (ADS)

    Bianchi, E.; Guglielmon, J.; Hackl, L.; Yokomizo, N.

    2016-10-01

    We introduce a new loop expansion that provides a resolution of the identity in the Hilbert space of loop quantum gravity on a fixed graph. We work in the bosonic representation obtained by the canonical quantization of the spinorial formalism. The resolution of the identity gives a tool for implementing the projection of states in the full bosonic representation onto the space of solutions to the Gauss and area matching constraints of loop quantum gravity. This procedure is particularly efficient in the semiclassical regime, leading to explicit expressions for the loop expansions of coherent, heat kernel and squeezed states.

  5. High temperature storage loop :

    SciTech Connect

    Gill, David Dennis; Kolb, William J.

    2013-07-01

    A three year plan for thermal energy storage (TES) research was created at Sandia National Laboratories in the spring of 2012. This plan included a strategic goal of providing test capability for Sandia and for the nation in which to evaluate high temperature storage (>650ÀC) technology. The plan was to scope, design, and build a flow loop that would be compatible with a multitude of high temperature heat transfer/storage fluids. The High Temperature Storage Loop (HTSL) would be reconfigurable so that it was useful for not only storage testing, but also for high temperature receiver testing and high efficiency power cycle testing as well. In that way, HTSL was part of a much larger strategy for Sandia to provide a research and testing platform that would be integral for the evaluation of individual technologies funded under the SunShot program. DOEs SunShot program seeks to reduce the price of solar technologies to 6/kWhr to be cost competitive with carbon-based fuels. The HTSL project sought to provide evaluation capability for these SunShot supported technologies. This report includes the scoping, design, and budgetary costing aspects of this effort

  6. Ekpyrotic loop quantum cosmology

    SciTech Connect

    Wilson-Ewing, Edward

    2013-08-01

    We consider the ekpyrotic paradigm in the context of loop quantum cosmology. In loop quantum cosmology the classical big-bang singularity is resolved due to quantum gravity effects, and so the contracting ekpyrotic branch of the universe and its later expanding phase are connected by a smooth bounce. Thus, it is possible to explicitly determine the evolution of scalar perturbations, from the contracting ekpyrotic phase through the bounce and to the post-bounce expanding epoch. The possibilities of having either one or two scalar fields have been suggested for the ekpyrotic universe, and both cases will be considered here. In the case of a single scalar field, the constant mode of the curvature perturbations after the bounce is found to have a blue spectrum. On the other hand, for the two scalar field ekpyrotic model where scale-invariant entropy perturbations source additional terms in the curvature perturbations, the power spectrum in the post-bounce expanding cosmology is shown to be nearly scale-invariant and so agrees with observations.

  7. Temporary umbilical loop colostomy for anorectal malformations.

    PubMed

    Hamada, Yoshinori; Takada, Kohei; Nakamura, Yusuke; Sato, Masahito; Kwon, A-Hon

    2012-11-01

    Transumbilical surgical procedures have been reported to be a feasible, safe, and cosmetically excellent procedure for various pediatric surgical diseases. Umbilical loop colostomies have previously been created in patients with Hirschsprung's disease, but not in patients with anorectal malformations (ARMs). We assessed the feasibility and cosmetic results of temporal umbilical loop colostomy (TULC) in patients with ARMs. A circumferential skin incision was made at the base of the umbilical cord under general anesthesia. The skin, subcutaneous tissue, and fascia were cored out vertically, and the umbilical vessels and urachal remnant were individually ligated apart from the opening in the fascia. A loop colostomy was created in double-barreled fashion with a high chimney more than 2 cm above the level of the skin. The final size of the opening in the skin and fascia was modified according to the size of the bowel. The bowel wall was fixed separately to the peritoneum and fascia with interrupted 5-0 absorbable sutures. The bowel was opened longitudinally and everted without suturing to the skin. The loop was divided 7 days postoperatively, and diversion of the oral bowel was completed. The colostomy was closed 2-3 months after posterior saggital anorectoplasty through a peristomal skin incision followed by end-to-end anastomosis. Final wound closure was performed in a semi-opened fashion to create a deep umbilicus. TULCs were successfully created in seven infants with rectourethral bulbar fistula or rectovestibular fistula. Postoperative complications included mucosal prolapse in one case. No wound infection or spontaneous umbilical ring narrowing was observed. Skin problems were minimal, and stoma care could easily be performed by attaching stoma bag. Healing of umbilical wounds after TULC closure was excellent. The umbilicus may be an alternative stoma site for temporary loop colostomy in infants with intermediate-type anorectal malformations, who undergo radical

  8. The double loop mattress suture

    PubMed Central

    Biddlestone, John; Samuel, Madan; Creagh, Terry; Ahmad, Tariq

    2014-01-01

    An interrupted stitch type with favorable tissue characteristics will reduce local wound complications. We describe a novel high-strength, low-tension repair for the interrupted closure of skin, cartilage, and muscle, the double loop mattress stitch, and compare it experimentally with other interrupted closure methods. The performance of the double loop mattress technique in porcine cartilage and skeletal muscle is compared with the simple, mattress, and loop mattress interrupted sutures in both a novel porcine loading chamber and mechanical model. Wound apposition is assessed by electron microscopy. The performance of the double loop mattress in vivo was confirmed using a series of 805 pediatric laparotomies/laparoscopies. The double loop mattress suture is 3.5 times stronger than the loop mattress in muscle and 1.6 times stronger in cartilage (p ≤ 0.001). Additionally, the double loop mattress reduces tissue tension by 66% compared with just 53% for the loop mattress (p ≤ 0.001). Wound gapping is equal, and wound eversion appears significantly improved (p ≤ 0.001) compared with the loop mattress in vitro. In vivo, the double loop mattress performs as well as the loop mattress and significantly better than the mattress stitch in assessments of wound eversion and dehiscence. There were no episodes of stitch extrusion in our series of patients. The mechanical advantage of its intrinsic pulley arrangement gives the double loop mattress its favorable properties. Wound dehiscence is reduced because this stitch type is stronger and exerts less tension on the tissue than the mattress stitch. We advocate the use of this novel stitch wherever a high-strength, low-tension repair is required. These properties will enhance wound repair, and its application will be useful to surgeons of all disciplines. PMID:24698436

  9. Enhancement of surface nonwettability by grafting loops.

    PubMed

    Pei, Han-Wen; Liu, Xiao-Li; Liu, Hong; Zhu, You-Liang; Lu, Zhong-Yuan

    2017-02-08

    We present a computer simulation study on the nonwettability of a flat surface tethered with deformable looped polymer chains. Two kinds of loops are studied: monodispersed loops (loops with the same length) and polydispersed loops (loops with different lengths). Both kinds of loops include two arrangements: with regularly tethered sites and with randomly tethered sites. Regularly grafted loops form typical grooves on the surface, while randomly grafted loops form a more rugged surface. For monodispersed loops, we analyze the factors that influence the nonwettability when varying the rigidity of the loops. The loops are divided into two categories based on their rigidity according to our previous analysis procedure (Phys. Chem. Chem. Phys., 2016, 18, 18767-18775): rigid loops and flexible loops. It is found that the loop can partially form a re-entrant-like structure, which is helpful to increase the nonwettability of the surface. The surfaces with grafted loops have increased nonwettability, especially those grafted with flexible chains. However, the contact angle on the loop structure cannot further increase for the rigid chains due to a large top layer density (Phys. Chem. Chem. Phys., 2016, 18, 18767-18775). For polydispersed loops, the contact angle is highly related to the rigidity of the long loops that contact the droplet. Different from monodispersed loops, the mechanism of the nonwettability of polydispersed loops is attributed to the supporting ability (rigidity) of long loops.

  10. Unstable anisotropic loop quantum cosmology

    SciTech Connect

    Nelson, William; Sakellariadou, Mairi

    2009-09-15

    We study stability conditions of the full Hamiltonian constraint equation describing the quantum dynamics of the diagonal Bianchi I model in the context of loop quantum cosmology. Our analysis has shown robust evidence of an instability in the explicit implementation of the difference equation, implying important consequences for the correspondence between the full loop quantum gravity theory and loop quantum cosmology. As a result, one may question the choice of the quantization approach, the model of lattice refinement, and/or the role of the ambiguity parameters; all these should, in principle, be dictated by the full loop quantum gravity theory.

  11. Loop Heat Pipe Startup Behaviors

    NASA Technical Reports Server (NTRS)

    Ku, Jentung

    2016-01-01

    A loop heat pipe must start successfully before it can commence its service. The startup transient represents one of the most complex phenomena in the loop heat pipe operation. This paper discusses various aspects of loop heat pipe startup behaviors. Topics include the four startup scenarios, the initial fluid distribution between the evaporator and reservoir that determines the startup scenario, factors that affect the fluid distribution between the evaporator and reservoir, difficulties encountered during the low power startup, and methods to enhance the startup success. Also addressed are the pressure spike and pressure surge during the startup transient, and repeated cycles of loop startup and shutdown under certain conditions.

  12. Loop-the-Loop: Bringing Theory into Practice

    ERIC Educational Resources Information Center

    Suwonjandee, N.; Asavapibhop, B.

    2012-01-01

    During the Thai high-school physics teacher training programme, we used an aluminum loop-the-loop system built by the Institute for the Promotion of Teaching Science and Technology (IPST) to demonstrate a circular motion and investigate the concept of the conservation of mechanical energy. There were 27 high-school teachers from three provinces,…

  13. Jejunal access loop cholangiogram and intervention using image guided access.

    PubMed

    Amitha Vikrama, K S; Keshava, S N; Surendrababu, N R S; Moses, V; Joseph, P; Vyas, F; Sitaram, V

    2010-02-01

    Jejunal access loop is fashioned in patients who undergo Roux en Y hepaticojejunostomy and biliary intervention is anticipated on follow up. Post-operative study of the biliary tree through the access loop is usually done under fluoroscopic guidance. We present a series of 20 access loop cholangiograms performed in our institution between August 2004 and November 2008. We aimed to evaluate the safety and efficacy of the procedure and to highlight the role of CT guidance in procuring access. Access loop was accessed using CT (n = 13), ultrasound (n = 3) or fluoroscopic guidance (n = 4). Fluoroscopy was used for performing cholangiograms and interventions. Twelve studies had balloon plasty of the stricture at anastomotic site or high up in the hepatic ducts. Seven studies showed normal cholangiogram. Plasty was unsuccessful in one study. Technical success in accessing the jejunal access loop was 100%; in cannulation of anastomotic site and balloon plasty it was 95%. One case required two attempts. Procedure-related complications were not seen. All patients who underwent balloon plasty of the stricture were doing well for variable lengths of time. Access loop cholangiogram and interventions are safe and effective. CT guidance in locating/procuring the access loop is a good technique.

  14. Dynamic PID loop control

    SciTech Connect

    Pei, L.; Klebaner, A.; Theilacker, J.; Soyars, W.; Martinez, A.; Bossert, R.; DeGraff, B.; Darve, C.; /Fermilab

    2011-06-01

    The Horizontal Test Stand (HTS) SRF Cavity and Cryomodule 1 (CM1) of eight 9-cell, 1.3GHz SRF cavities are operating at Fermilab. For the cryogenic control system, how to hold liquid level constant in the cryostat by regulation of its Joule-Thompson JT-valve is very important after cryostat cool down to 2.0 K. The 72-cell cryostat liquid level response generally takes a long time delay after regulating its JT-valve; therefore, typical PID control loop should result in some cryostat parameter oscillations. This paper presents a type of PID parameter self-optimal and Time-Delay control method used to reduce cryogenic system parameters oscillation.

  15. Pulse thermal loop

    NASA Technical Reports Server (NTRS)

    Weislogel, Mark M. (Inventor)

    2002-01-01

    A pulse thermal loop heat transfer system includes a means to use pressure rises in a pair of evaporators to circulate a heat transfer fluid. The system includes one or more valves that iteratively, alternately couple the outlets the evaporators to the condenser. While flow proceeds from one of the evaporators to the condenser, heating creates a pressure rise in the other evaporator, which has its outlet blocked to prevent fluid from exiting the other evaporator. When the flow path is reconfigured to allow flow from the other evaporator to the condenser, the pressure in the other evaporator is used to circulate a pulse of fluid through the system. The reconfiguring of the flow path, by actuating or otherwise changing the configuration of the one or more valves, may be triggered when a predetermined pressure difference between the evaporators is reached.

  16. Vortex loops and Majoranas

    SciTech Connect

    Chesi, Stefano; Jaffe, Arthur; Loss, Daniel; Pedrocchi, Fabio L.

    2013-11-15

    We investigate the role that vortex loops play in characterizing eigenstates of interacting Majoranas. We give some general results and then focus on ladder Hamiltonian examples as a test of further ideas. Two methods yield exact results: (i) A mapping of certain spin Hamiltonians to quartic interactions of Majoranas shows that the spectra of these two examples coincide. (ii) In cases with reflection-symmetric Hamiltonians, we use reflection positivity for Majoranas to characterize vortices in the ground states. Two additional methods suggest wider applicability of these results: (iii) Numerical evidence suggests similar behavior for certain systems without reflection symmetry. (iv) A perturbative analysis also suggests similar behavior without the assumption of reflection symmetry.

  17. Loop Quantum Gravity.

    PubMed

    Rovelli, Carlo

    2008-01-01

    The problem of describing the quantum behavior of gravity, and thus understanding quantum spacetime, is still open. Loop quantum gravity is a well-developed approach to this problem. It is a mathematically well-defined background-independent quantization of general relativity, with its conventional matter couplings. Today research in loop quantum gravity forms a vast area, ranging from mathematical foundations to physical applications. Among the most significant results obtained so far are: (i) The computation of the spectra of geometrical quantities such as area and volume, which yield tentative quantitative predictions for Planck-scale physics. (ii) A physical picture of the microstructure of quantum spacetime, characterized by Planck-scale discreteness. Discreteness emerges as a standard quantum effect from the discrete spectra, and provides a mathematical realization of Wheeler's "spacetime foam" intuition. (iii) Control of spacetime singularities, such as those in the interior of black holes and the cosmological one. This, in particular, has opened up the possibility of a theoretical investigation into the very early universe and the spacetime regions beyond the Big Bang. (iv) A derivation of the Bekenstein-Hawking black-hole entropy. (v) Low-energy calculations, yielding n-point functions well defined in a background-independent context. The theory is at the roots of, or strictly related to, a number of formalisms that have been developed for describing background-independent quantum field theory, such as spin foams, group field theory, causal spin networks, and others. I give here a general overview of ideas, techniques, results and open problems of this candidate theory of quantum gravity, and a guide to the relevant literature.

  18. Uranyl Nitrate Flow Loop

    SciTech Connect

    Ladd-Lively, Jennifer L

    2008-10-01

    The objectives of the work discussed in this report were to: (1) develop a flow loop that would simulate the purified uranium-bearing aqueous stream exiting the solvent extraction process in a natural uranium conversion plant (NUCP); (2) develop a test plan that would simulate normal operation and disturbances that could be anticipated in an NUCP; (3) use the flow loop to test commercially available flowmeters for use as safeguards monitors; and (4) recommend a flowmeter for production-scale testing at an NUCP. There has been interest in safeguarding conversion plants because the intermediate products [uranium dioxide (UO{sub 2}), uranium tetrafluoride (UF{sub 4}), and uranium hexafluoride (UF{sub 6})] are all suitable uranium feedstocks for producing special nuclear materials. Furthermore, if safeguards are not applied virtually any nuclear weapons program can obtain these feedstocks without detection by the International Atomic Energy Agency (IAEA). Historically, IAEA had not implemented safeguards until the purified UF{sub 6} product was declared as feedstock for enrichment plants. H. A. Elayat et al. provide a basic definition of a safeguards system: 'The function of a safeguards system on a chemical conversion plant is in general terms to verify that no useful nuclear material is being diverted to use in a nuclear weapons program'. The IAEA now considers all highly purified uranium compounds as candidates for safeguarding. DOE is currently interested in 'developing instruments, tools, strategies, and methods that could be of use to the IAEA in the application of safeguards' for materials found in the front end of the nuclear fuel cycle-prior to the production of the uranium hexafluoride or oxides that have been the traditional starting point for IAEA safeguards. Several national laboratories, including Oak Ridge, Los Alamos, Lawrence Livermore, and Brookhaven, have been involved in developing tools or techniques for safeguarding conversion plants. This study

  19. Protein Loop Closure Using Orientational Restraints from NMR Data

    NASA Astrophysics Data System (ADS)

    Tripathy, Chittaranjan; Zeng, Jianyang; Zhou, Pei; Donald, Bruce Randall

    Protein loops often play important roles in biological functions such as binding, recognition, catalytic activities and allosteric regulation. Modeling loops that are biophysically sensible is crucial to determining the functional specificity of a protein. A variety of algorithms ranging from robotics-inspired inverse kinematics methods to fragmentbased homology modeling techniques have been developed to predict protein loops. However, determining the 3D structures of loops using global orientational restraints on internuclear vectors, such as those obtained from residual dipolar coupling (RDC) data in solution Nuclear Magnetic Resonance (NMR) spectroscopy, has not been well studied. In this paper, we present a novel algorithm that determines the protein loop conformations using a minimal amount of RDC data. Our algorithm exploits the interplay between the sphero-conics derived from RDCs and the protein kinematics, and formulates the loop structure determination problem as a system of low-degree polynomial equations that can be solved exactly and in closed form. The roots of these polynomial equations, which encode the candidate conformations, are searched systematically, using efficient and provable pruning strategies that triage the vast majority of conformations, to enumerate or prune all possible loop conformations consistent with the data. Our algorithm guarantees completeness by ensuring that a possible loop conformation consistent with the data is never missed. This data-driven algorithm provides a way to assess the structural quality from experimental data with minimal modeling assumptions. We applied our algorithm to compute the loops of human ubiquitin, the FF Domain 2 of human transcription elongation factor CA150 (FF2), the DNA damage inducible protein I (DinI) and the third IgG-binding domain of Protein G (GB3) from experimental RDC data. A comparison of our results versus those obtained by using traditional structure determination protocols on the

  20. Complete normal ordering 1: Foundations

    NASA Astrophysics Data System (ADS)

    Ellis, John; Mavromatos, Nick E.; Skliros, Dimitri P.

    2016-08-01

    We introduce a new prescription for quantising scalar field theories (in generic spacetime dimension and background) perturbatively around a true minimum of the full quantum effective action, which is to 'complete normal order' the bare action of interest. When the true vacuum of the theory is located at zero field value, the key property of this prescription is the automatic cancellation, to any finite order in perturbation theory, of all tadpole and, more generally, all 'cephalopod' Feynman diagrams. The latter are connected diagrams that can be disconnected into two pieces by cutting one internal vertex, with either one or both pieces free from external lines. In addition, this procedure of 'complete normal ordering' (which is an extension of the standard field theory definition of normal ordering) reduces by a substantial factor the number of Feynman diagrams to be calculated at any given loop order. We illustrate explicitly the complete normal ordering procedure and the cancellation of cephalopod diagrams in scalar field theories with non-derivative interactions, and by using a point splitting 'trick' we extend this result to theories with derivative interactions, such as those appearing as non-linear σ-models in the world-sheet formulation of string theory. We focus here on theories with trivial vacua, generalising the discussion to non-trivial vacua in a follow-up paper.

  1. Three-loop calculations in non-abelian gauge theories

    NASA Astrophysics Data System (ADS)

    Tarasov, O. V.; Vladimirov, A. A.

    2013-09-01

    A detailed description of the method for analytical evaluation of the three-loop contributions to renormalization group functions is presented. This method is employed to calculate the charge renormalization function and anomalous dimensions for non-Abelian gauge theories with fermions in the three-loop approximation. A three-loop expression for the effective charge of QCD is given. Charge renormalization effects in the SU(4)-supersymmetric gauge model is shown to vanish at this level. A complete list of required formulas is given in Appendix. The above-mentioned results of three-loop calculations were published by the present authors (with A.Yu. Zharkov and L.V. Avdeev) in 1980 in Physics Letters B. The present text, which treats the subject in more details and contains a lot of calculational techniques, was also published in 1980 as the JINR Communication E2-80-483.

  2. Two-loop SL(2) form factors and maximal transcendentality

    NASA Astrophysics Data System (ADS)

    Loebbert, Florian; Sieg, Christoph; Wilhelm, Matthias; Yang, Gang

    2016-12-01

    Form factors of composite operators in the SL(2) sector of N = 4 SYM theory are studied up to two loops via the on-shell unitarity method. The non-compactness of this subsector implies the novel feature and technical challenge of an unlimited number of loop momenta in the integrand's numerator. At one loop, we derive the full minimal form factor to all orders in the dimensional regularisation parameter. At two loops, we construct the complete integrand for composite operators with an arbitrary number of covariant derivatives, and we obtain the remainder functions as well as the dilatation operator for composite operators with up to three covariant derivatives. The remainder functions reveal curious patterns suggesting a hidden maximal uniform transcendentality for the full form factor. Finally, we speculate about an extension of these patterns to QCD.

  3. The Projectile Inside the Loop

    ERIC Educational Resources Information Center

    Varieschi, Gabriele U.

    2006-01-01

    The loop-the-loop demonstration can be easily adapted to study the kinematics of projectile motion, when the moving body falls inside the apparatus. Video capturing software can be used to reveal peculiar geometrical effects of this simple but educational experiment.

  4. RCD+: Fast loop modeling server

    PubMed Central

    López-Blanco, José Ramón; Canosa-Valls, Alejandro Jesús; Li, Yaohang; Chacón, Pablo

    2016-01-01

    Modeling loops is a critical and challenging step in protein modeling and prediction. We have developed a quick online service (http://rcd.chaconlab.org) for ab initio loop modeling combining a coarse-grained conformational search with a full-atom refinement. Our original Random Coordinate Descent (RCD) loop closure algorithm has been greatly improved to enrich the sampling distribution towards near-native conformations. These improvements include a new workflow optimization, MPI-parallelization and fast backbone angle sampling based on neighbor-dependent Ramachandran probability distributions. The server starts by efficiently searching the vast conformational space from only the loop sequence information and the environment atomic coordinates. The generated closed loop models are subsequently ranked using a fast distance-orientation dependent energy filter. Top ranked loops are refined with the Rosetta energy function to obtain accurate all-atom predictions that can be interactively inspected in an user-friendly web interface. Using standard benchmarks, the average root mean squared deviation (RMSD) is 0.8 and 1.4 Å for 8 and 12 residues loops, respectively, in the challenging modeling scenario in where the side chains of the loop environment are fully remodeled. These results are not only very competitive compared to those obtained with public state of the art methods, but also they are obtained ∼10-fold faster. PMID:27151199

  5. Improved code-tracking loop

    NASA Technical Reports Server (NTRS)

    Laflame, D. T.

    1980-01-01

    Delay-locked loop tracks pseudonoise codes without introducing dc timing errors, because it is not sensitive to gain imbalance between signal processing arms. "Early" and "late" reference codes pass in combined form through both arms, and each arm acts on both codes. Circuit accomodates 1 dB weaker input signals with tracking ability equal to that of tau-dither loops.

  6. Callan-Giddings-Harvey-Strominger vacuum in loop quantum gravity and singularity resolution

    NASA Astrophysics Data System (ADS)

    Corichi, Alejandro; Olmedo, Javier; Rastgoo, Saeed

    2016-10-01

    We study here a complete quantization of a Callan-Giddings-Harvey-Strominger vacuum model following loop quantum gravity techniques. Concretely, we adopt a formulation of the model in terms of a set of new variables that resemble the ones commonly employed in spherically symmetric loop quantum gravity. The classical theory consists of two pairs of canonical variables plus a scalar and diffeomorphism (first class) constraints. We consider a suitable redefinition of the Hamiltonian constraint such that the new constraint algebra (with structure constants) is well adapted to the Dirac quantization approach. For it, we adopt a polymeric representation for both the geometry and the dilaton field. On the one hand, we find a suitable invariant domain of the scalar constraint operator, and we construct explicitly its solution space. There, the eigenvalues of the dilaton and the metric operators cannot vanish locally, allowing us to conclude that singular geometries are ruled out in the quantum theory. On the other hand, the physical Hilbert space is constructed out of them, after group averaging the previous states with the diffeomorphism constraint. In turn, we identify the standard observable corresponding to the mass of the black hole at the boundary, in agreement with the classical theory. We also construct an additional observable on the bulk associated with the square of the dilaton field, with no direct classical analog.

  7. Loop Heat Pipe Startup Behaviors

    NASA Technical Reports Server (NTRS)

    Ku, Jentung

    2014-01-01

    A loop heat pipe must start successfully before it can commence its service. The start-up transient represents one of the most complex phenomena in the loop heat pipe operation. This paper discusses various aspects of loop heat pipe start-up behaviors. Topics include the four start-up scenarios, the initial fluid distribution between the evaporator and reservoir that determines the start-up scenario, factors that affect the fluid distribution between the evaporator and reservoir, difficulties encountered during the low power start-up, and methods to enhance the start-up success. Also addressed are the thermodynamic constraint between the evaporator and reservoir in the loop heat pipe operation, the superheat requirement for nucleate boiling, pressure spike and pressure surge during the start-up transient, and repeated cycles of loop start-up andshutdown under certain conditions.

  8. Higher dimensional loop quantum cosmology

    NASA Astrophysics Data System (ADS)

    Zhang, Xiangdong

    2016-07-01

    Loop quantum cosmology (LQC) is the symmetric sector of loop quantum gravity. In this paper, we generalize the structure of loop quantum cosmology to the theories with arbitrary spacetime dimensions. The isotropic and homogeneous cosmological model in n+1 dimensions is quantized by the loop quantization method. Interestingly, we find that the underlying quantum theories are divided into two qualitatively different sectors according to spacetime dimensions. The effective Hamiltonian and modified dynamical equations of n+1 dimensional LQC are obtained. Moreover, our results indicate that the classical big bang singularity is resolved in arbitrary spacetime dimensions by a quantum bounce. We also briefly discuss the similarities and differences between the n+1 dimensional model and the 3+1 dimensional one. Our model serves as a first example of higher dimensional loop quantum cosmology and offers the possibility to investigate quantum gravity effects in higher dimensional cosmology.

  9. Quantum Einstein-Maxwell fields: A unified viewpoint from the loop representation

    NASA Astrophysics Data System (ADS)

    Gambini, Rodolfo; Pullin, Jorge

    1993-06-01

    We propose a naive unification of electromagnetism and general relativity based on enlarging the gauge group of Ashtekar's variables. We construct the connection and loop representations and analyze the space of states. In the loop representation, the wave functions depend on two loops, each of them carrying information about both gravitation and electromagnetism. We find that the Chern-Simons form and the Jones polynomial play a role in the model.

  10. Lorentz covariance of loop quantum gravity

    NASA Astrophysics Data System (ADS)

    Rovelli, Carlo; Speziale, Simone

    2011-05-01

    The kinematics of loop gravity can be given a manifestly Lorentz-covariant formulation: the conventional SU(2)-spin-network Hilbert space can be mapped to a space K of SL(2,C) functions, where Lorentz covariance is manifest. K can be described in terms of a certain subset of the projected spin networks studied by Livine, Alexandrov and Dupuis. It is formed by SL(2,C) functions completely determined by their restriction on SU(2). These are square-integrable in the SU(2) scalar product, but not in the SL(2,C) one. Thus, SU(2)-spin-network states can be represented by Lorentz-covariant SL(2,C) functions, as two-component photons can be described in the Lorentz-covariant Gupta-Bleuler formalism. As shown by Wolfgang Wieland in a related paper, this manifestly Lorentz-covariant formulation can also be directly obtained from canonical quantization. We show that the spinfoam dynamics of loop quantum gravity is locally SL(2,C)-invariant in the bulk, and yields states that are precisely in K on the boundary. This clarifies how the SL(2,C) spinfoam formalism yields an SU(2) theory on the boundary. These structures define a tidy Lorentz-covariant formalism for loop gravity.

  11. Complete data listings for CSEM soundings on Kilauea Volcano, Hawaii

    SciTech Connect

    Kauahikaua, J.; Jackson, D.B.; Zablocki, C.J.

    1983-01-01

    This document contains complete data from a controlled-source electromagnetic (CSEM) sounding/mapping project at Kilauea volcano, Hawaii. The data were obtained at 46 locations about a fixed-location, horizontal, polygonal loop source in the summit area of the volcano. The data consist of magnetic field amplitudes and phases at excitation frequencies between 0.04 and 8 Hz. The vector components were measured in a cylindrical coordinate system centered on the loop source. 5 references.

  12. Modeling loop entropy.

    PubMed

    Chirikjian, Gregory S

    2011-01-01

    Proteins fold from a highly disordered state into a highly ordered one. Traditionally, the folding problem has been stated as one of predicting "the" tertiary structure from sequential information. However, new evidence suggests that the ensemble of unfolded forms may not be as disordered as once believed, and that the native form of many proteins may not be described by a single conformation, but rather an ensemble of its own. Quantifying the relative disorder in the folded and unfolded ensembles as an entropy difference may therefore shed light on the folding process. One issue that clouds discussions of "entropy" is that many different kinds of entropy can be defined: entropy associated with overall translational and rotational Brownian motion, configurational entropy, vibrational entropy, conformational entropy computed in internal or Cartesian coordinates (which can even be different from each other), conformational entropy computed on a lattice, each of the above with different solvation and solvent models, thermodynamic entropy measured experimentally, etc. The focus of this work is the conformational entropy of coil/loop regions in proteins. New mathematical modeling tools for the approximation of changes in conformational entropy during transition from unfolded to folded ensembles are introduced. In particular, models for computing lower and upper bounds on entropy for polymer models of polypeptide coils both with and without end constraints are presented. The methods reviewed here include kinematics (the mathematics of rigid-body motions), classical statistical mechanics, and information theory.

  13. Wilson loops in minimal surfaces

    SciTech Connect

    Drukker, Nadav; Gross, David J.; Ooguri, Hirosi

    1999-04-27

    The AdS/CFT correspondence suggests that the Wilson loop of the large N gauge theory with N = 4 supersymmetry in 4 dimensions is described by a minimal surface in AdS{sub 5} x S{sup 5}. The authors examine various aspects of this proposal, comparing gauge theory expectations with computations of minimal surfaces. There is a distinguished class of loops, which the authors call BPS loops, whose expectation values are free from ultra-violet divergence. They formulate the loop equation for such loops. To the extent that they have checked, the minimal surface in AdS{sub 5} x S{sup 5} gives a solution of the equation. The authors also discuss the zig-zag symmetry of the loop operator. In the N = 4 gauge theory, they expect the zig-zag symmetry to hold when the loop does not couple the scalar fields in the supermultiplet. They will show how this is realized for the minimal surface.

  14. Self-sustained hydrodynamic oscillations in a natural-circulation two-phase-flow boiling loop

    NASA Technical Reports Server (NTRS)

    Jain, K. C.

    1969-01-01

    Results of an experimental and theoretical study of factors affecting self-sustaining hydrodynamic oscillations in boiling-water loops are reported. Data on flow variables, and the effects of geometry, subcooling and pressure on the development of oscillatory behavior in a natural-circulation two-phase-flow boiling loop are included.

  15. Digital phase-locked loop

    NASA Technical Reports Server (NTRS)

    Cliff, R. A. (Inventor)

    1975-01-01

    An digital phase-locked loop is provided for deriving a loop output signal from an accumulator output terminal. A phase detecting exclusive OR gate is fed by the loop digital input and output signals. The output of the phase detector is a bi-level digital signal having a duty cycle indicative of the relative phase of the input and output signals. The accumulator is incremented at a first rate in response to a first output level of the phase detector and at a second rate in response to a second output level of the phase detector.

  16. Open loop distribution system design

    SciTech Connect

    Glamocanin, V. ); Filipovic, V. . Elektrotechnicki fakulet)

    1993-10-01

    The ability to supply consumers of an urban area, with minimum interruption during a feeder segment or substation transformer outage, is assured by a uniform cable size of the feeder segments along the entire loop. Based on the criterion of the uniform cable size, a loop configuration is obtained first by minimizing the installation costs, and then an open loop solution is found by minimizing the power losses. Heuristic rules are proposed and used to obtain an initial solution, as well as to improve current solutions.

  17. Phase-locked tracking loops for LORAN-C

    NASA Technical Reports Server (NTRS)

    Burhans, R. W.

    1978-01-01

    Portable battery operated LORAN-C receivers were fabricated to evaluate simple envelope detector methods with hybrid analog to digital phase locked loop sensor processors. The receivers are used to evaluate LORAN-C in general aviation applications. Complete circuit details are given for the experimental sensor and readout system.

  18. Ultraviolet behavior of N = 8 supergravity at four loops.

    PubMed

    Bern, Z; Carrasco, J J M; Dixon, L J; Johansson, H; Roiban, R

    2009-08-21

    We describe the construction of the complete four-loop four-particle amplitude of N=8 supergravity. The amplitude is ultraviolet finite, not only in four dimensions, but in five dimensions as well. The observed extra cancellations provide additional nontrivial evidence that N=8 supergravity in four dimensions may be ultraviolet finite to all orders of perturbation theory.

  19. Muon loop light-by-light contribution to hyperfine splitting in muonium.

    PubMed

    Eides, Michael I; Shelyuto, Valery A

    2014-05-02

    Three-loop corrections to hyperfine splitting in muonium, generated by the gauge-invariant sets of diagrams with muon and tauon loop light-by-light scattering blocks, are calculated. These results complete calculations of all light-by-light scattering contributions to hyperfine splitting in muonium.

  20. Optical loop framing

    SciTech Connect

    Kalibjian, R.; Chong, Y.P.; Prono, D.S.; Cavagnolo, H.R.

    1984-06-01

    The ATA provides an electron beam pulse of 70-ns duration at a 1-Hz rate. Our present optical diagnostics technique involve the imaging of the visible light generated by the beam incident onto the plant of a thin sheet of material. It has already been demonstrated that the light generated has a sufficiently fast temporal reponse in performing beam diagnostics. Notwithstanding possible beam emittance degradation due to scattering in the thin sheet, the observation of beam spatial profiles with relatively high efficiencies has provided data complementary to that obtained from beam wall current monitors and from various x-ray probes and other electrical probes. The optical image sensor consists of a gated, intensified television system. The gate pulse of the image intensifier can be appropriately delayed to give frames that are time-positioned from the head to the tail of the beam with a minimum gate time of 5-ns. The spatial correlation of the time frames from pulse to pulse is very good for a stable electron beam; however, when instabilities do occur, it is difficult to properly assess the spatial composition of the head and the tail of the beam on a pulse-to-pulse basis. Multiple gating within a pulse duration becomes desirable but cannot be performed because the recycle time (20-ms) of the TV system is much longer than the beam pulse. For this reason we have developed an optical-loop framing technique that will allow the recording of two frames within one pulse duration with our present gated/intensified TV system.

  1. Dark matter elastic scattering through Higgs loops

    NASA Astrophysics Data System (ADS)

    Berlin, Asher; Hooper, Dan; McDermott, Samuel D.

    2015-12-01

    We consider a complete list of simplified models in which Majorana dark matter particles annihilate at tree level to h h or h Z final states and calculate the loop-induced elastic scattering cross section with nuclei in each case. Expressions for these annihilation and elastic scattering cross sections are provided and can be easily applied to a variety of UV-complete models. We identify several phenomenologically viable scenarios, including dark matter that annihilates through the s -channel exchange of a spin-zero mediator or through the t -channel exchange of a fermion. Although the elastic scattering cross sections predicted in this class of models are generally quite small, XENON1T and LZ should be sensitive to significant regions of this parameter space. Models in which the dark matter annihilates to h h or h Z can also generate a gamma-ray signal that is compatible with the excess observed from the Galactic center.

  2. Three-Loop Radiative-Recoil Corrections to Hyperfine Splitting in Muonium: Diagrams with Polarization Loops

    SciTech Connect

    Eides, Michael I.; Shelyuto, Valery A.

    2009-09-25

    We consider three-loop radiative-recoil corrections to hyperfine splitting in muonium generated by the diagrams with electron and muon vacuum polarizations. We calculate single-logarithmic and nonlogarithmic contributions of order alpha{sup 3}(m/M)E{sub F} generated by gauge invariant sets of diagrams with electron and muon polarization insertions in the electron and muon factors. Combining these corrections with the older results, we obtain total contribution to hyperfine splitting generated by all diagrams with electron and muon polarization loops. The calculation of this contribution completes an important stage in the implementation of the program of reduction of the theoretical uncertainty of hyperfine splitting below 10 Hz. The new results improve the theory of hyperfine splitting and affect the value of the electron-muon mass ratio extracted from experimental data on muonium hyperfine splitting.

  3. Loop Electrosurgical Excision Procedure (LEEP)

    MedlinePlus

    ... that acts like a scalpel (surgical knife). An electric current is passed through the loop, which cuts away ... A procedure in which an instrument works with electric current to destroy tissue. Local Anesthesia: The use of ...

  4. Integrated optical phase locked loop.

    SciTech Connect

    Lentine, Anthony L.; Kim, Jungwon; Trotter, Douglas Chandler; DeRose, Christopher T.; Kartner, Franz X.; Byun, Hyunil; Nejadmalayeri, Amir H.; Watts, Michael R.; Zortman, William A.

    2010-12-01

    A silicon photonics based integrated optical phase locked loop is utilized to synchronize a 10.2 GHz voltage controlled oscillator with a 509 MHz mode locked laser, achieving 32 fs integrated jitter over 300 kHz bandwidth.

  5. SDO Sees Flourishing Magnetic Loops

    NASA Video Gallery

    A bright set of loops near the edge of the sun’s face grew and shifted quickly after the magnetic field was disrupted by a small eruption on Nov. 25, 2015. Charged particles emitting light in extre...

  6. SDO Sees Brightening Magnetic Loops

    NASA Video Gallery

    Two active regions sprouted arches of bundled magnetic loops in this video from NASA’s Solar Dynamics Observatory taken on Nov. 11-12, 2015. Charged particles spin along the magnetic field, tracing...

  7. Observations of loops and prominences

    NASA Technical Reports Server (NTRS)

    Strong, Keith T.

    1994-01-01

    We review recent observations by the Yohkoh-SXT (Soft X-ray Telescope) in collaboration with other spacecraft and ground-based observatories of coronal loops and prominences. These new results point to problems that SoHO will be able to address. With a unique combination of rapid-cadence digital imaging (greater than or equal to 32 s full-disk and greater than or equal to 2 s partial-frame images), high spatial resolution (greater than or equal to 2.5 arcsec pixels), high sensitivity (EM less than or equal to 10(exp 42) cm(exp -3)), a low-scatter mirror, and large dynamic range, SXT can observe a vast range of targets on the Sun. Over the first 21 months of Yohkoh operations SXT has taken over one million images of the corona and so is building up an invaluable long-term database on the large-scale corona and loop geometry. The most striking thing about the SXT images is the range of loop sizes and shapes. The active regions are a bright tangle of magnetic field lines, surrounded by a network of large-scale quiet-Sun loops stretching over distances in excess of 105 km. The cross-section of most loops seems to be constant. Loops displaying significant Gamma's are the exception, not the rule, implying the presence of widespread currents in the corona. All magnetic structures show changes. Time scales range from seconds to months. The question of how these structures are formed, become filled with hot plasma, and are maintained is still open. While we see the propagation of brightenings along the length of active-region loops and in X-ray jets with velocities of several hundred km/s, much higher velocities are seen in the quiet Sun. In XBP flares, for example, velocities of over 1000 km/s are common. Active-region loops seem to be in constant motion, moving slowly outward, carrying plasma with them. During flares, loops often produce localized brightenings at the base and later at the apex of the loop. Quiescent filaments and prominences have been observed regularly

  8. LETS: An Expressional Loop Notation.

    DTIC Science & Technology

    1982-10-01

    r - ..’ -rI- x- - r ,11 V~ The Expressional Metaphor 2- Waters i "The Expressional Metaphor ’lhe key property of expressions which makes them...development of a notation which has the property of decomposability. Viewing Loops as Expressions Involving Sequences In order to represent loops as...a DEFUNS or LETS. For example, the function EPLIST takes in a discnbodied plist and returns two values: a sequence of the property names. and a

  9. Closed loop spray cooling apparatus

    NASA Technical Reports Server (NTRS)

    Alger, D. L.; Schwab, W. B.; Furman, E. R. (Inventor)

    1979-01-01

    A closed loop apparatus for jet spraying coolant against the back of a radiation target is described. The coolant is circulated through a closed loop with a bubble of inert gas being maintained around the spray. Mesh material is disposed between the bubble and the surface of the liquid coolant which is below the bubble at a predetermined level. In a second arrangement no inert gas is used, the bubble consists of vapor produced when the coolant is sprayed against the target.

  10. BOOK REVIEW: A First Course in Loop Quantum Gravity A First Course in Loop Quantum Gravity

    NASA Astrophysics Data System (ADS)

    Dittrich, Bianca

    2012-12-01

    Students who are interested in quantum gravity usually face the difficulty of working through a large amount of prerequisite material before being able to deal with actual quantum gravity. A First Course in Loop Quantum Gravity by Rodolfo Gambini and Jorge Pullin, aimed at undergraduate students, marvellously succeeds in starting from the basics of special relativity and covering basic topics in Hamiltonian dynamics, Yang Mills theory, general relativity and quantum field theory, ending with a tour on current (loop) quantum gravity research. This is all done in a short 173 pages! As such the authors cannot cover any of the subjects in depth and indeed this book should be seen more as a motivation and orientation guide so that students can go on to follow the hints for further reading. Also, as there are many subjects to cover beforehand, slightly more than half of the book is concerned with more general subjects (special and general relativity, Hamiltonian dynamics, constrained systems, quantization) before the starting point for loop quantum gravity, the Ashtekar variables, are introduced. The approach taken by the authors is heuristic and uses simplifying examples in many places. However they take care in motivating all the main steps and succeed in presenting the material pedagogically. Problem sets are provided throughout and references for further reading are given. Despite the shortness of space, alternative viewpoints are mentioned and the reader is also referred to experimental results and bounds. In the second half of the book the reader gets a ride through loop quantum gravity; the material covers geometric operators and their spectra, the Hamiltonian constraints, loop quantum cosmology and, more broadly, black hole thermodynamics. A glimpse of recent developments and open problems is given, for instance a discussion on experimental predictions, where the authors carefully point out the very preliminary nature of the results. The authors close with an

  11. THE CORONAL LOOP INVENTORY PROJECT

    SciTech Connect

    Schmelz, J. T.; Pathak, S.; Christian, G. M.; Dhaliwal, R. S. S.; Paul, K. S.

    2015-11-01

    Most coronal physicists now seem to agree that loops are composed of tangled magnetic strands and have both isothermal and multithermal cross-field temperature distributions. As yet, however, there is no information on the relative importance of each of these categories, and we do not know how common one is with respect to the other. In this paper, we investigate these temperature properties for all loop segments visible in the 171-Å image of AR 11294, which was observed by the Atmospheric Imaging Assembly (AIA) on 2011 September 15. Our analysis revealed 19 loop segments, but only 2 of these were clearly isothermal. Six additional segments were effectively isothermal, that is, the plasma emission to which AIA is sensitive could not be distinguished from isothermal emission, within measurement uncertainties. One loop had both isothermal transition region and multithermal coronal solutions. Another five loop segments require multithermal plasma to reproduce the AIA observations. The five remaining loop segments could not be separated reliably from the background in the crucial non-171-Å AIA images required for temperature analysis. We hope that the direction of coronal heating models and the efforts modelers spend on various heating scenarios will be influenced by these results.

  12. Loop Models from SOHO Observations

    NASA Astrophysics Data System (ADS)

    Landini, M.; Brković , A.; Landi, E.; Rüedi, I.; Solanki, S.

    1999-01-01

    The Coronal Diagnostic Spectrometer (CDS) on SOHO is a grazing/normal incidence spectrograph, aimed to produce stigmatic spectra of selected regions of the solar surface in six spectral windows of the extreme ultraviolet from 150 Å to 785 Å (Harrison et al. 1995). In the present work, CDS, EIT, MDI and Yohkoh observations of active region lops have been analyzed. These observations are part of JOP 54. CDS monochromatic images from lines at different temperatures have been co-aligned with EIT and MDI images, and loop structures have been clearly identified using Fe XVI emission lines. Density sensitive lines and lines from adjacent stages of ionization of Fe ions have been used to measure electron density and temperature along the loop length; these measurements have been used to determine the electron pressure along the loop and test the constant pressure assumption commonly used in loop modeling. The observations have been compared with a static, isobaric loop model (Landini and Monsignori Fossi 1975) assuming a temperature-constant heating function in the energy balance equation. Good agreement is found for the temperature distribution along the loop at the coronal level. The model pressure is somewhat higher than obtained from density sensitive line ratios.

  13. Amodal Completion in Bonobos

    ERIC Educational Resources Information Center

    Nagasaka, Yasuo; Brooks, Daniel I.; Wasserman, Edward A.

    2010-01-01

    We trained two bonobos to discriminate among occluded, complete, and incomplete stimuli. The occluded stimulus comprised a pair of colored shapes, one of which appeared to occlude the other. The complete and incomplete stimuli involved the single shape that appeared to have been partially covered in the occluded stimulus; the complete stimulus…

  14. LOOPREF: A Fluid Code for the Simulation of Coronal Loops

    NASA Technical Reports Server (NTRS)

    deFainchtein, Rosalinda; Antiochos, Spiro; Spicer, Daniel

    1998-01-01

    This report documents the code LOOPREF. LOOPREF is a semi-one dimensional finite element code that is especially well suited to simulate coronal-loop phenomena. It has a full implementation of adaptive mesh refinement (AMR), which is crucial for this type of simulation. The AMR routines are an improved version of AMR1D. LOOPREF's versatility makes is suitable to simulate a wide variety of problems. In addition to efficiently providing very high resolution in rapidly changing regions of the domain, it is equipped to treat loops of variable cross section, any non-linear form of heat conduction, shocks, gravitational effects, and radiative loss.

  15. Congenital complete heart block.

    PubMed Central

    Agarwala, B.; Sheikh, Z.; Cibils, L. A.

    1996-01-01

    Congenital complete heart block in utero has become diagnosed more frequently with the clinical use of fetal echocardiography. The fetus with complete heart block may remain asymptomatic or may develop congestive heart failure. Congenital complete heart block is more frequently seen in infants of mothers with systemic lupus erythematosus, both clinically manifested and subclinical systemic lupus erythematosus with positive antibodies (SS-A and SS-B antibodies). At birth, the neonate with complete heart block may remain asymptomatic and may not require a pacemaker to increase the heart rate. The indications for a pacemaker in neonates with complete heart block have been discussed. Both in-utero and neonatal management of congenital complete heart block are discussed to manage congestive heart failure in a fetus. Four patients with congenital complete heart block are presented covering a broad spectrum of clinical presentation, diagnosis, and management both in the fetal and neonatal period. Images Figure 1 PMID:8961692

  16. Gravity quantized: Loop quantum gravity with a scalar field

    SciTech Connect

    Domagala, Marcin; Kaminski, Wojciech; Giesel, Kristina; Lewandowski, Jerzy

    2010-11-15

    ...''but we do not have quantum gravity.'' This phrase is often used when analysis of a physical problem enters the regime in which quantum gravity effects should be taken into account. In fact, there are several models of the gravitational field coupled to (scalar) fields for which the quantization procedure can be completed using loop quantum gravity techniques. The model we present in this paper consists of the gravitational field coupled to a scalar field. The result has similar structure to the loop quantum cosmology models, except that it involves all the local degrees of freedom of the gravitational field because no symmetry reduction has been performed at the classical level.

  17. Estimating two-loop radiative effects in the MOLLER experiment

    SciTech Connect

    Aleksejevs, A. G.; Barkanova, S. G.; Zykunov, V. A.; Kuraev, E. A.

    2013-07-15

    Within the on-shell renormalization scheme, two-loop electroweak corrections to the parityviolating polarization asymmetry in the reaction e{sup -}e{sup -} {yields} e{sup -}e{sup -}({gamma}, {gamma}{gamma}) were estimated for the MOLLER experiment at JLab. The infrared divergence and the imaginary part of the amplitude were taken completely under control. Relevant compact expressions obtained by using asymptotic methods are free from unphysical parameters and are convenient for analysis and for numerical estimations. A numerical analysis revealed a significant scale of two-loop effects and the need for taking them into account in the MOLLER experiment.

  18. Quantifying a Systems Map: Network Analysis of a Childhood Obesity Causal Loop Diagram

    PubMed Central

    Johnstone, Michael; Creighton, Doug; de la Haye, Kayla; Allender, Steven

    2016-01-01

    Causal loop diagrams developed by groups capture a shared understanding of complex problems and provide a visual tool to guide interventions. This paper explores the application of network analytic methods as a new way to gain quantitative insight into the structure of an obesity causal loop diagram to inform intervention design. Identification of the structural features of causal loop diagrams is likely to provide new insights into the emergent properties of complex systems and analysing central drivers has the potential to identify leverage points. The results found the structure of the obesity causal loop diagram to resemble commonly observed empirical networks known for efficient spread of information. Known drivers of obesity were found to be the most central variables along with others unique to obesity prevention in the community. While causal loop diagrams are often specific to single communities, the analytic methods provide means to contrast and compare multiple causal loop diagrams for complex problems. PMID:27788224

  19. Filter for third order phase locked loops

    NASA Technical Reports Server (NTRS)

    Crow, R. B.; Tausworthe, R. C. (Inventor)

    1973-01-01

    Filters for third-order phase-locked loops are used in receivers to acquire and track carrier signals, particularly signals subject to high doppler-rate changes in frequency. A loop filter with an open-loop transfer function and set of loop constants, setting the damping factor equal to unity are provided.

  20. Kalman Orbit Optimized Loop Tracking

    NASA Technical Reports Server (NTRS)

    Young, Lawrence E.; Meehan, Thomas K.

    2011-01-01

    Under certain conditions of low signal power and/or high noise, there is insufficient signal to noise ratio (SNR) to close tracking loops with individual signals on orbiting Global Navigation Satellite System (GNSS) receivers. In addition, the processing power available from flight computers is not great enough to implement a conventional ultra-tight coupling tracking loop. This work provides a method to track GNSS signals at very low SNR without the penalty of requiring very high processor throughput to calculate the loop parameters. The Kalman Orbit-Optimized Loop (KOOL) tracking approach constitutes a filter with a dynamic model and using the aggregate of information from all tracked GNSS signals to close the tracking loop for each signal. For applications where there is not a good dynamic model, such as very low orbits where atmospheric drag models may not be adequate to achieve the required accuracy, aiding from an IMU (inertial measurement unit) or other sensor will be added. The KOOL approach is based on research JPL has done to allow signal recovery from weak and scintillating signals observed during the use of GPS signals for limb sounding of the Earth s atmosphere. That approach uses the onboard PVT (position, velocity, time) solution to generate predictions for the range, range rate, and acceleration of the low-SNR signal. The low- SNR signal data are captured by a directed open loop. KOOL builds on the previous open loop tracking by including feedback and observable generation from the weak-signal channels so that the MSR receiver will continue to track and provide PVT, range, and Doppler data, even when all channels have low SNR.

  1. Functional importance of GGXG sequence motifs in putative reentrant loops of 2HCT and ESS transport proteins.

    PubMed

    Dobrowolski, Adam; Lolkema, Juke S

    2009-08-11

    The 2HCT and ESS families are two families of secondary transporters. Members of the two families are unrelated in amino acid sequence but share similar hydropathy profiles, which suggest a similar folding of the proteins in membranes. Structural models show two homologous domains containing five transmembrane segments (TMSs) each, with a reentrant or pore loop between the fourth and fifth TMSs in each domain. Here we show that GGXG sequence motifs present in the putative reentrant loops are important for the activity of the transporters. Mutation of the conserved Gly residues to Cys in the motifs of the Na(+)-citrate transporter CitS in the 2HCT family and the Na(+)-glutamate transporter GltS in the ESS family resulted in strongly reduced transport activity. Similarly, mutation of the variable residue "X" to Cys in the N-terminal half of GltS essentially inactivated the transporter. The corresponding mutations in the N- and C-terminal halves of CitS reduced transport activity to 60 and 25% of that of the wild type, respectively. Residual activity of any of the mutants could be further reduced by treatment with the membrane permeable thiol reagent N-ethylmaleimide (NEM). The X to Cys mutation (S405C) in the cytoplasmic loop in the C-terminal half of CitS rendered the protein sensitive to the bulky, membrane impermeable thiol reagent 4-acetamido-4'-maleimidylstilbene-2,2'-disulfonic acid (AmdiS) added at the periplasmic side of the membrane, providing further evidence that this part of the loop is positioned between the transmembrane segments. The putative reentrant loop in the C-terminal half of the ESS family does not contain the GGXG motif, but a conserved stretch rich in Gly residues. Cysteine-scanning mutagenesis of a stretch of 18 residues in the GltS protein revealed two residues important for function. Mutant N356C was completely inactivated by treatment with NEM, and mutant P351C appeared to be the counterpart of mutant S405C of CitS; the mutant was

  2. OBSERVATIONS OF PLASMA UPFLOW IN A WARM LOOP WITH HINODE/EIS

    SciTech Connect

    Tripathi, Durgesh; Mason, Helen E.; Del Zanna, Giulio; Bradshaw, Steven

    2012-07-20

    A complete understanding of Doppler shift in active region loops can help probe the basic physical mechanism involved into the heating of those loops. Here, we present observations of upflows in coronal loops detected in a range of temperatures (log T = 5.8-6.2). The loop was not discernible above these temperatures. The speed of upflow was strongest at the footpoint and decreased with height. The upflow speed at the footpoint was about 20 km s{sup -1} in Fe VIII, which decreased with temperature, being about 13 km s{sup -1} in Fe X, about 8 km s{sup -1} in Fe XII, and about 4 km s{sup -1} in Fe XIII. To the best of our knowledge, this is the first observation providing evidence of upflow of plasma in coronal loop structures at these temperatures. We interpret these observations as evidence of chromospheric evaporation in quasi-static coronal loops.

  3. Study of the open loop and closed loop oscillator techniques

    SciTech Connect

    Baker, Benjamin; Riley, Tony; Langbehn, Adam; Imel, George R.; Benzerga, M. Lamine; Aryal, Harishchandra

    2015-07-01

    This paper presents some aspects of a five year study undertaken at Idaho State University of the measurement of very small worth reactivity samples comparing open and closed loop oscillator techniques. The study conclusively demonstrated the equivalency of the two techniques with regard to uncertainties in reactivity values, i.e., limited by reactor noise. As those results are thoroughly documented in recent publications, in this paper we will concentrate on the support work that was necessary. For example, we describe in some detail the construction and calibration of a pilot rod for the closed loop system. We discuss the campaign to measure the required reactor parameters necessary for inverse-kinetics. Finally, we briefly discuss the transfer of the open loop technique to other reactor systems. (authors)

  4. Lattice calculation of the Polyakov loop and Polyakov loop correlators

    NASA Astrophysics Data System (ADS)

    Weber, Johannes Heinrich

    2017-03-01

    We discuss calculations of the Polyakov loop and of Polyakov loop correlators using lattice gauge theory. We simulate QCD with 2+1 flavors and almost physical quark masses using the highly improved staggered quark action (HISQ).We demonstrate that the entropy derived from the Polyakov loop is a good probe of color screening. In particular, it allows for scheme independent and quantitative conclusions about the deconfinement aspects of the crossover and for a rigorous study of the onset of weak-coupling behavior at high temperatures. We examine the correlators for small and large separations and identify vacuum-like and screening regimes in the thermal medium. We demonstrate that gauge-independent screening properties can be obtained even from gauge-fixed singlet correlators and that we can pin down the asymptotic regime.

  5. Complete amino acid sequence of heavy chain variable regions derived from two monoclonal anti-p-azophenylarsonate antibodies of BALB/c mice expressing the major cross-reactive idiotype of the A/J strain

    PubMed Central

    1984-01-01

    The primary structure of A/J anti-p-azophenylarsonate (anti-Ars) antibodies expressing the major A-strain cross-reactive idiotype (CRIA) has provided important insights into issues of antibody diversity and the molecular basis of idiotypy in this important model system. Until recently, this idiotype was thought to be rarely, if ever, expressed in BALB/c mice. Indeed, it has been reported that BALB/c mice lack the heavy chain variable segment (VH) gene that is utilized by the entire family of anti-Ars antibodies expressing the A/J CRI. Recently, however, it has been possible to elicit CRIA+, Ars binding antibodies in the BALB/c strain by immunizing first with anti-CRI and then with antigen. Such BALB/c, CRIA+ anti-Ars antibodies can be induced occasionally with antigen alone. VH region amino acid sequences are described for two CRIA+ hybridoma products derived from BALB/c mice. While remarkably similar to each other, their VH segments (1-98) differ from the VH segments of A/J CRIA+, anti-Ars antibodies in over 40 positions. Rather than the usual JH2 gene segment used by most A/J CRIA+ anti-Ars antibodies, one BALB/c CRIA+ hybridoma utilizes a JH1 gene segment, while the other uses a JH4. However, the D segments of both of the BALB/c antibodies are remarkably homologous to the D segments of several A/J CRIA+ antibodies sequenced previously, as are the amino terminal amino acid sequences of their light chains. These data imply that BALB/c mice express the A/J CRIA by producing antibodies with very similar, if not identical, light chain and heavy chain D segments, but in the context of different VH and JH gene segments than their A/J counterparts. The results document that molecules that share serologic specificities can have vastly different primary structures. PMID:6207261

  6. Design and Modeling of a Variable Heat Rejection Radiator

    NASA Technical Reports Server (NTRS)

    Miller, Jennifer R.; Birur, Gajanana C.; Ganapathi, Gani B.; Sunada, Eric T.; Berisford, Daniel F.; Stephan, Ryan

    2011-01-01

    Variable Heat Rejection Radiator technology needed for future NASA human rated & robotic missions Primary objective is to enable a single loop architecture for human-rated missions (1) Radiators are typically sized for maximum heat load in the warmest continuous environment resulting in a large panel area (2) Large radiator area results in fluid being susceptible to freezing at low load in cold environment and typically results in a two-loop system (3) Dual loop architecture is approximately 18% heavier than single loop architecture (based on Orion thermal control system mass) (4) Single loop architecture requires adaptability to varying environments and heat loads

  7. Loop coupled resonator optical waveguides.

    PubMed

    Song, Junfeng; Luo, Lian-Wee; Luo, Xianshu; Zhou, Haifeng; Tu, Xiaoguang; Jia, Lianxi; Fang, Qing; Lo, Guo-Qiang

    2014-10-06

    We propose a novel coupled resonator optical waveguide (CROW) structure that is made up of a waveguide loop. We theoretically investigate the forbidden band and conduction band conditions in an infinite periodic lattice. We also discuss the reflection- and transmission- spectra, group delay in finite periodic structures. Light has a larger group delay at the band edge in a periodic structure. The flat band pass filter and flat-top group delay can be realized in a non-periodic structure. Scattering matrix method is used to calculate the effects of waveguide loss on the optical characteristics of these structures. We also introduce a tunable coupling loop waveguide to compensate for the fabrication variations since the coupling coefficient of the directional coupler in the loop waveguide is a critical factor in determining the characteristics of a loop CROW. The loop CROW structure is suitable for a wide range of applications such as band pass filters, high Q microcavity, and optical buffers and so on.

  8. Bandwidth controller for phase-locked-loop

    NASA Technical Reports Server (NTRS)

    Brockman, Milton H. (Inventor)

    1992-01-01

    A phase locked loop utilizing digital techniques to control the closed loop bandwidth of the RF carrier phase locked loop in a receiver provides high sensitivity and a wide dynamic range for signal reception. After analog to digital conversion, a digital phase locked loop bandwidth controller provides phase error detection with automatic RF carrier closed loop tracking bandwidth control to accommodate several modes of transmission.

  9. Entanglement entropy of Wilson loops: Holography and matrix models

    NASA Astrophysics Data System (ADS)

    Gentle, Simon A.; Gutperle, Michael

    2014-09-01

    A half-Bogomol'nyi-Prasad-Sommerfeld circular Wilson loop in N=4 SU(N) supersymmetric Yang-Mills theory in an arbitrary representation is described by a Gaussian matrix model with a particular insertion. The additional entanglement entropy of a spherical region in the presence of such a loop was recently computed by Lewkowycz and Maldacena using exact matrix model results. In this paper we utilize the supergravity solutions that are dual to such Wilson loops in a representation with order N2 boxes to calculate this entropy holographically. Employing the matrix model results of Gomis, Matsuura, Okuda and Trancanelli we express this holographic entanglement entropy in a form that can be compared with the calculation of Lewkowycz and Maldacena. We find complete agreement between the matrix model and holographic calculations.

  10. On the Convergence in Effective Loop Quantum Cosmology

    SciTech Connect

    Corichi, Alejandro; Vukasinac, Tatjana; Zapata, Jose Antonio

    2010-07-12

    In Loop Quantum Cosmology (LQC) there is a discreteness parameter {lambda}, that has been heuristically associated to a fundamental granularity of quantum geometry. It is also possible to consider {lambda} as a regulator in the same spirit as that used in lattice field theory, where it specifies a regular lattice in the real line. A particular quantization of the k = 0 FLRW loop cosmological model yields a completely solvable model, known as solvable loop quantum cosmology(sLQC). In this contribution, we consider effective classical theories motivated by sLQC and study their {lambda}-dependence, with a special interest on the limit {lambda}{yields}0 and the role of the evolution parameter in the convergence of such limit.

  11. Digital phase-lock loop

    NASA Technical Reports Server (NTRS)

    Thomas, Jr., Jess B. (Inventor)

    1991-01-01

    An improved digital phase lock loop incorporates several distinctive features that attain better performance at high loop gain and better phase accuracy. These features include: phase feedback to a number-controlled oscillator in addition to phase rate; analytical tracking of phase (both integer and fractional cycles); an amplitude-insensitive phase extractor; a more accurate method for extracting measured phase; a method for changing loop gain during a track without loss of lock; and a method for avoiding loss of sampled data during computation delay, while maintaining excellent tracking performance. The advantages of using phase and phase-rate feedback are demonstrated by comparing performance with that of rate-only feedback. Extraction of phase by the method of modeling provides accurate phase measurements even when the number-controlled oscillator phase is discontinuously updated.

  12. Fast loop modeling for protein structures

    NASA Astrophysics Data System (ADS)

    Zhang, Jiong; Nguyen, Son; Shang, Yi; Xu, Dong; Kosztin, Ioan

    2015-03-01

    X-ray crystallography is the main method for determining 3D protein structures. In many cases, however, flexible loop regions of proteins cannot be resolved by this approach. This leads to incomplete structures in the protein data bank, preventing further computational study and analysis of these proteins. For instance, all-atom molecular dynamics (MD) simulation studies of structure-function relationship require complete protein structures. To address this shortcoming, we have developed and implemented an efficient computational method for building missing protein loops. The method is database driven and uses deep learning and multi-dimensional scaling algorithms. We have implemented the method as a simple stand-alone program, which can also be used as a plugin in existing molecular modeling software, e.g., VMD. The quality and stability of the generated structures are assessed and tested via energy scoring functions and by equilibrium MD simulations. The proposed method can also be used in template-based protein structure prediction. Work supported by the National Institutes of Health [R01 GM100701]. Computer time was provided by the University of Missouri Bioinformatics Consortium.

  13. Wilson loops and QCD/string scattering amplitudes

    SciTech Connect

    Makeenko, Yuri; Olesen, Poul

    2009-07-15

    We generalize modern ideas about the duality between Wilson loops and scattering amplitudes in N=4 super Yang-Mills theory to large N QCD by deriving a general relation between QCD meson scattering amplitudes and Wilson loops. We then investigate properties of the open-string disk amplitude integrated over reparametrizations. When the Wilson-loop is approximated by the area behavior, we find that the QCD scattering amplitude is a convolution of the standard Koba-Nielsen integrand and a kernel. As usual poles originate from the first factor, whereas no (momentum-dependent) poles can arise from the kernel. We show that the kernel becomes a constant when the number of external particles becomes large. The usual Veneziano amplitude then emerges in the kinematical regime, where the Wilson loop can be reliably approximated by the area behavior. In this case, we obtain a direct duality between Wilson loops and scattering amplitudes when spatial variables and momenta are interchanged, in analogy with the N=4 super Yang-Mills theory case.

  14. Latino College Completion: Maine

    ERIC Educational Resources Information Center

    Excelencia in Education (NJ1), 2012

    2012-01-01

    In 2009, Excelencia in Education launched the Ensuring America's Future initiative to inform, organize, and engage leaders in a tactical plan to increase Latino college completion. An executive summary of Latino College Completion in 50 states synthesizes information on 50 state factsheets and builds on the national benchmarking guide. Each…

  15. Latino College Completion: Connecticut

    ERIC Educational Resources Information Center

    Excelencia in Education (NJ1), 2012

    2012-01-01

    In 2009, Excelencia in Education launched the Ensuring America's Future initiative to inform, organize, and engage leaders in a tactical plan to increase Latino college completion. An executive summary of Latino College Completion in 50 states synthesizes information on 50 state factsheets and builds on the national benchmarking guide. Each…

  16. Latino College Completion: California

    ERIC Educational Resources Information Center

    Excelencia in Education (NJ1), 2012

    2012-01-01

    In 2009, Excelencia in Education launched the Ensuring America's Future initiative to inform, organize, and engage leaders in a tactical plan to increase Latino college completion. An executive summary of Latino College Completion in 50 states synthesizes information on 50 state factsheets and builds on the national benchmarking guide. Each…

  17. Latino College Completion: Ohio

    ERIC Educational Resources Information Center

    Excelencia in Education (NJ1), 2012

    2012-01-01

    In 2009, Excelencia in Education launched the Ensuring America's Future initiative to inform, organize, and engage leaders in a tactical plan to increase Latino college completion. An executive summary of Latino College Completion in 50 states synthesizes information on 50 state factsheets and builds on the national benchmarking guide. Each…

  18. Latino College Completion: Massachusetts

    ERIC Educational Resources Information Center

    Excelencia in Education (NJ1), 2012

    2012-01-01

    In 2009, Excelencia in Education launched the Ensuring America's Future initiative to inform, organize, and engage leaders in a tactical plan to increase Latino college completion. An executive summary of Latino College Completion in 50 states synthesizes information on 50 state factsheets and builds on the national benchmarking guide. Each…

  19. Latino College Completion: Florida

    ERIC Educational Resources Information Center

    Excelencia in Education (NJ1), 2012

    2012-01-01

    In 2009, Excelencia in Education launched the Ensuring America's Future initiative to inform, organize, and engage leaders in a tactical plan to increase Latino college completion. An executive summary of Latino College Completion in 50 states synthesizes information on 50 state factsheets and builds on the national benchmarking guide. Each…

  20. Latino College Completion: Iowa

    ERIC Educational Resources Information Center

    Excelencia in Education (NJ1), 2012

    2012-01-01

    In 2009, Excelencia in Education launched the Ensuring America's Future initiative to inform, organize, and engage leaders in a tactical plan to increase Latino college completion. An executive summary of Latino College Completion in 50 states synthesizes information on 50 state factsheets and builds on the national benchmarking guide. Each…

  1. Latino College Completion: Hawaii

    ERIC Educational Resources Information Center

    Excelencia in Education (NJ1), 2012

    2012-01-01

    In 2009, Excelencia in Education launched the Ensuring America's Future initiative to inform, organize, and engage leaders in a tactical plan to increase Latino college completion. An executive summary of Latino College Completion in 50 states synthesizes information on 50 state factsheets and builds on the national benchmarking guide. Each…

  2. Latino College Completion: Mississippi

    ERIC Educational Resources Information Center

    Excelencia in Education (NJ1), 2012

    2012-01-01

    In 2009, Excelencia in Education launched the Ensuring America's Future initiative to inform, organize, and engage leaders in a tactical plan to increase Latino college completion. An executive summary of Latino College Completion in 50 states synthesizes information on 50 state factsheets and builds on the national benchmarking guide. Each…

  3. Latino College Completion: Maryland

    ERIC Educational Resources Information Center

    Excelencia in Education (NJ1), 2012

    2012-01-01

    In 2009, Excelencia in Education launched the Ensuring America's Future initiative to inform, organize, and engage leaders in a tactical plan to increase Latino college completion. An executive summary of Latino College Completion in 50 states synthesizes information on 50 state factsheets and builds on the national benchmarking guide. Each…

  4. Latino College Completion: Montana

    ERIC Educational Resources Information Center

    Excelencia in Education (NJ1), 2012

    2012-01-01

    In 2009, Excelencia in Education launched the Ensuring America's Future initiative to inform, organize, and engage leaders in a tactical plan to increase Latino college completion. An executive summary of Latino College Completion in 50 states synthesizes information on 50 state factsheets and builds on the national benchmarking guide. Each…

  5. Latino College Completion: Nevada

    ERIC Educational Resources Information Center

    Excelencia in Education (NJ1), 2012

    2012-01-01

    In 2009, Excelencia in Education launched the Ensuring America's Future initiative to inform, organize, and engage leaders in a tactical plan to increase Latino college completion. An executive summary of Latino College Completion in 50 states synthesizes information on 50 state factsheets and builds on the national benchmarking guide. Each…

  6. Many Ways to Loop DNA

    PubMed Central

    Griffith, Jack D.

    2013-01-01

    In the 1960s, I developed methods for directly visualizing DNA and DNA-protein complexes using an electron microscope. This made it possible to examine the shape of DNA and to visualize proteins as they fold and loop DNA. Early applications included the first visualization of true nucleosomes and linkers and the demonstration that repeating tracts of adenines can cause a curvature in DNA. The binding of DNA repair proteins, including p53 and BRCA2, has been visualized at three- and four-way junctions in DNA. The trombone model of DNA replication was directly verified, and the looping of DNA at telomeres was discovered. PMID:24005675

  7. All digital pulsewidth control loop

    NASA Astrophysics Data System (ADS)

    Huang, Hong-Yi; Jan, Shiun-Dian; Pu, Ruei-Iun

    2013-03-01

    This work presents an all-digital pulsewidth control loop (ADPWCL). The proposed system accepts a wide range of input duty cycles and performs a fast correction to the target output pulsewidth. An all-digital delay-locked loop (DLL) with fast locking time using a simplified time to digital converter and a new differential two-step delay element is proposed. The area of the delay element is much smaller than that in conventional designs, while having the same delay range. A test chip is verified in a 0.18-µm CMOS process. The measured duty cycle ranges from 4% to 98% with 7-bit resolution.

  8. Reionization from cosmic string loops

    SciTech Connect

    Olum, Ken D.; Vilenkin, Alexander

    2006-09-15

    Loops formed from a cosmic string network at early times would act as seeds for early formation of halos, which would form galaxies and lead to early reionization. With reasonable guesses about astrophysical and string parameters, the cosmic string scale G{mu} must be no more than about 3x10{sup -8} to avoid conflict with the reionization redshift found by WMAP. The bound is much stronger for superstring models with a small string reconnection probability. For values near the bound, cosmic string loops may explain the discrepancy between the WMAP value and theoretical expectations.

  9. Calculation of multi-loop superstring amplitudes

    NASA Astrophysics Data System (ADS)

    Danilov, G. S.

    2016-12-01

    The multi-loop interaction amplitudes in the closed, oriented superstring theory are obtained by the integration of local amplitudes. The local amplitude is represented by a sum over the spinning string local amplitudes. The spinning string local amplitudes are given explicitly through super-Schottky group parameters and through interaction vertex coordinates on the (1| 1) complex, non-split supermanifold. The obtained amplitudes are free from divergences. They are consistent with the world-sheet spinning string symmetries. The vacuum amplitude vanishes along with 1-, 2- and 3-point amplitudes of massless states. The vanishing of the above-mentioned amplitude occurs after the integration of the corresponding local amplitude has been performed over the super-Schottky group limiting points and over interaction vertex coordinate, except for those (3| 2) variables which are fixed due to SL(2)-symmetry.

  10. A comprehensive sensitivity analysis of central-loop MRS data

    NASA Astrophysics Data System (ADS)

    Behroozmand, Ahmad; Auken, Esben; Dalgaard, Esben; Rejkjaer, Simon

    2014-05-01

    sensitivity kernels of different separated-loop MRS soundings are studied and compared with that of the conventional coincident-loop sounding. As a result, an optimal S/N is achieved using central-loop configuration. 2) The posterior parameter determination of central-loop MRS data (both synthetic and field examples) is studied in a joint MRS and TEM data analysis scheme. In the typical 1D earth parametrization, a complete MRS measurement forms the 1D MRS sensitivity kernels as a function of depth and pulse moment Q; here referred to as a 1D kernel structure. For the conventional coincident-loop configuration, the 1D kernel structure covers the excited earth's volume throughout the applied Qs. As a result, the shallower parts of the subsurface are mainly sampled using smaller Qs and the deeper parts are mainly sampled using higher Qs. For central-loop configuration, however, the 1D kernel structure represents a superior behavior compared to coincident loop configuration. The results of this study highlight advantages of central-loop MRS data and suggest that it can be beneficial to develop MRS instrumentation where the receiver system is separated from the transmitter system.

  11. Smooth Wilson loops in N=4 non-chiral superspace

    NASA Astrophysics Data System (ADS)

    Beisert, Niklas; Müller, Dennis; Plefka, Jan; Vergu, Cristian

    2015-12-01

    We consider a supersymmetric Wilson loop operator for 4d N = 4 super Yang-Mills theory which is the natural object dual to the AdS 5 × S 5 superstring in the AdS/CFT correspondence. It generalizes the traditional bosonic 1 /2 BPS Maldacena-Wilson loop operator and completes recent constructions in the literature to smooth (non-light-like) loops in the full N=4 non-chiral superspace. This Wilson loop operator enjoys global super-conformal and local kappa-symmetry of which a detailed discussion is given. Moreover, the finiteness of its vacuum expectation value is proven at leading order in perturbation theory. We determine the leading vacuum expectation value for general paths both at the component field level up to quartic order in anti-commuting coordinates and in the full non-chiral superspace in suitable gauges. Finally, we discuss loops built from quadric splines joined in such a way that the path derivatives are continuous at the intersection.

  12. Regularization ambiguities in loop quantum gravity

    SciTech Connect

    Perez, Alejandro

    2006-02-15

    One of the main achievements of loop quantum gravity is the consistent quantization of the analog of the Wheeler-DeWitt equation which is free of ultraviolet divergences. However, ambiguities associated to the intermediate regularization procedure lead to an apparently infinite set of possible theories. The absence of an UV problem--the existence of well-behaved regularization of the constraints--is intimately linked with the ambiguities arising in the quantum theory. Among these ambiguities is the one associated to the SU(2) unitary representation used in the diffeomorphism covariant 'point-splitting' regularization of the nonlinear functionals of the connection. This ambiguity is labeled by a half-integer m and, here, it is referred to as the m ambiguity. The aim of this paper is to investigate the important implications of this ambiguity. We first study 2+1 gravity (and more generally BF theory) quantized in the canonical formulation of loop quantum gravity. Only when the regularization of the quantum constraints is performed in terms of the fundamental representation of the gauge group does one obtain the usual topological quantum field theory as a result. In all other cases unphysical local degrees of freedom arise at the level of the regulated theory that conspire against the existence of the continuum limit. This shows that there is a clear-cut choice in the quantization of the constraints in 2+1 loop quantum gravity. We then analyze the effects of the ambiguity in 3+1 gravity exhibiting the existence of spurious solutions for higher representation quantizations of the Hamiltonian constraint. Although the analysis is not complete in 3+1 dimensions - due to the difficulties associated to the definition of the physical inner product - it provides evidence supporting the definitions quantum dynamics of loop quantum gravity in terms of the fundamental representation of the gauge group as the only consistent possibilities. If the gauge group is SO(3) we find

  13. Regularization ambiguities in loop quantum gravity

    NASA Astrophysics Data System (ADS)

    Perez, Alejandro

    2006-02-01

    One of the main achievements of loop quantum gravity is the consistent quantization of the analog of the Wheeler-DeWitt equation which is free of ultraviolet divergences. However, ambiguities associated to the intermediate regularization procedure lead to an apparently infinite set of possible theories. The absence of an UV problem—the existence of well-behaved regularization of the constraints—is intimately linked with the ambiguities arising in the quantum theory. Among these ambiguities is the one associated to the SU(2) unitary representation used in the diffeomorphism covariant “point-splitting” regularization of the nonlinear functionals of the connection. This ambiguity is labeled by a half-integer m and, here, it is referred to as the m ambiguity. The aim of this paper is to investigate the important implications of this ambiguity. We first study 2+1 gravity (and more generally BF theory) quantized in the canonical formulation of loop quantum gravity. Only when the regularization of the quantum constraints is performed in terms of the fundamental representation of the gauge group does one obtain the usual topological quantum field theory as a result. In all other cases unphysical local degrees of freedom arise at the level of the regulated theory that conspire against the existence of the continuum limit. This shows that there is a clear-cut choice in the quantization of the constraints in 2+1 loop quantum gravity. We then analyze the effects of the ambiguity in 3+1 gravity exhibiting the existence of spurious solutions for higher representation quantizations of the Hamiltonian constraint. Although the analysis is not complete in 3+1 dimensions—due to the difficulties associated to the definition of the physical inner product—it provides evidence supporting the definitions quantum dynamics of loop quantum gravity in terms of the fundamental representation of the gauge group as the only consistent possibilities. If the gauge group is SO(3) we

  14. Loop Group Parakeet Virtual Cable Concept Demonstrator

    NASA Astrophysics Data System (ADS)

    Dowsett, T.; McNeill, T. C.; Reynolds, A. B.; Blair, W. D.

    2002-07-01

    The Parakeet Virtual Cable (PVC) concept demonstrator uses the Ethernet Local Area Network (LAN) laid for the Battle Command Support System (BCSS) to connect the Parakeet DVT(DA) (voice terminal) to the Parakeet multiplexer. This currently requires pairs of PVC interface units to be installed for each DVT(DA) . To reduce the cost of a PVC installation, the concept of a Loop Group Parakeet Virtual Cable (LGPVC) was proposed. This device was designed to replace the up to 30 PVC boxes and the multiplexer at the multiplexer side of a PVC installation. While the demonstrator is largely complete, testing has revealed an incomplete understanding of how to emulate the proprietary handshaking occurring between the circuit switch and the multiplexer. The LGPVC concept cannot yet be demonstrated.

  15. Geothermal Loop Experimental Facility. Final report

    SciTech Connect

    Not Available

    1980-04-01

    Research at the Geothermal Loop Experimental Facility was successfully concluded in September 1979. In 13,000 hours of operation over a three and one half year period, the nominal 10 megawatt electrical equivalent GLEF provided the opportunity to identify problems in working with highly saline geothermal fluids and to develop solutions that could be applied to a commercial geothermal power plant producing electricity. A seven and one half year period beginning in April 1972, with early well flow testing and ending in September 1979, with the completion of extensive facility and reservoir operations is covered. During this period, the facility was designed, constructed and operated in several configurations. A comprehensive reference document, addressing or referencing documentation of all the key areas investigated is presented.

  16. Adjustment of Open-Loop Settings to Improve Closed-Loop Results in Type 1 Diabetes: A Multicenter Randomized Trial

    PubMed Central

    Dassau, Eyal; Brown, Sue A.; Basu, Ananda; Pinsker, Jordan E.; Kudva, Yogish C.; Gondhalekar, Ravi; Patek, Steve; Lv, Dayu; Schiavon, Michele; Lee, Joon Bok; Dalla Man, Chiara; Hinshaw, Ling; Castorino, Kristin; Mallad, Ashwini; Dadlani, Vikash; McCrady-Spitzer, Shelly K.; McElwee-Malloy, Molly; Wakeman, Christian A.; Bevier, Wendy C.; Bradley, Paige K.; Kovatchev, Boris; Cobelli, Claudio; Zisser, Howard C.

    2015-01-01

    Context: Closed-loop control (CLC) relies on an individual's open-loop insulin pump settings to initialize the system. Optimizing open-loop settings before using CLC usually requires significant time and effort. Objective: The objective was to investigate the effects of a one-time algorithmic adjustment of basal rate and insulin to carbohydrate ratio open-loop settings on the performance of CLC. Design: This study reports a multicenter, outpatient, randomized, crossover clinical trial. Patients: Thirty-seven adults with type 1 diabetes were enrolled at three clinical sites. Interventions: Each subject's insulin pump settings were subject to a one-time algorithmic adjustment based on 1 week of open-loop (i.e., home care) data collection. Subjects then underwent two 27-hour periods of CLC in random order with either unchanged (control) or algorithmic adjusted basal rate and carbohydrate ratio settings (adjusted) used to initialize the zone-model predictive control artificial pancreas controller. Subject's followed their usual meal-plan and had an unannounced exercise session. Main Outcomes and Measures: Time in the glucose range was 80–140 mg/dL, compared between both arms. Results: Thirty-two subjects completed the protocol. Median time in CLC was 25.3 hours. The median time in the 80–140 mg/dl range was similar in both groups (39.7% control, 44.2% adjusted). Subjects in both arms of CLC showed minimal time spent less than 70 mg/dl (median 1.34% and 1.37%, respectively). There were no significant differences more than 140 mg/dL. Conclusions: A one-time algorithmic adjustment of open-loop settings did not alter glucose control in a relatively short duration outpatient closed-loop study. The CLC system proved very robust and adaptable, with minimal (<2%) time spent in the hypoglycemic range in either arm. PMID:26204135

  17. Closed-Loop Neuromorphic Benchmarks

    PubMed Central

    Stewart, Terrence C.; DeWolf, Travis; Kleinhans, Ashley; Eliasmith, Chris

    2015-01-01

    Evaluating the effectiveness and performance of neuromorphic hardware is difficult. It is even more difficult when the task of interest is a closed-loop task; that is, a task where the output from the neuromorphic hardware affects some environment, which then in turn affects the hardware's future input. However, closed-loop situations are one of the primary potential uses of neuromorphic hardware. To address this, we present a methodology for generating closed-loop benchmarks that makes use of a hybrid of real physical embodiment and a type of “minimal” simulation. Minimal simulation has been shown to lead to robust real-world performance, while still maintaining the practical advantages of simulation, such as making it easy for the same benchmark to be used by many researchers. This method is flexible enough to allow researchers to explicitly modify the benchmarks to identify specific task domains where particular hardware excels. To demonstrate the method, we present a set of novel benchmarks that focus on motor control for an arbitrary system with unknown external forces. Using these benchmarks, we show that an error-driven learning rule can consistently improve motor control performance across a randomly generated family of closed-loop simulations, even when there are up to 15 interacting joints to be controlled. PMID:26696820

  18. Telomeres thrown for a loop.

    PubMed

    Haber, James E

    2004-11-19

    A remarkable paper from the de Lange lab (Wang et al., 2004) in a recent issue of Cell reveals that homologous recombination can result in the abrupt shortening of telomeres in a process that appears to involve reciprocal crossing over within the t-loop structure that protects chromosome ends.

  19. Ponderomotive Acceleration in Coronal Loops

    NASA Astrophysics Data System (ADS)

    Dahlburg, R. B.; Laming, J. M.; Taylor, B. D.; Obenschain, K.

    2016-11-01

    Ponderomotive acceleration has been asserted to be a cause of the first ionization potential (FIP) effect, the well-known enhancement in abundance by a factor of 3-4 over photospheric values of elements in the solar corona with FIP less than about 10 eV. It is shown here by means of numerical simulations that ponderomotive acceleration occurs in solar coronal loops, with the appropriate magnitude and direction, as a “by-product” of coronal heating. The numerical simulations are performed with the HYPERION code, which solves the fully compressible three-dimensional magnetohydrodynamic equations including nonlinear thermal conduction and optically thin radiation. Numerical simulations of coronal loops with an axial magnetic field from 0.005 to 0.02 T and lengths from 25,000 to 75,000 km are presented. In the simulations the footpoints of the axial loop magnetic field are convected by random, large-scale motions. There is a continuous formation and dissipation of field-aligned current sheets, which act to heat the loop. As a consequence of coronal magnetic reconnection, small-scale, high-speed jets form. The familiar vortex quadrupoles form at reconnection sites. Between the magnetic footpoints and the corona the reconnection flow merges with the boundary flow. It is in this region that the ponderomotive acceleration occurs. Mirroring the character of the coronal reconnection, the ponderomotive acceleration is also found to be intermittent.

  20. The complete mitochondrial genome of the Yorkshire pig (Sus scrofa).

    PubMed

    Xu, Dong; Yang, Hu; Ma, Haiming

    2016-01-01

    This study aims to identify the complete nucleotide sequence of mitochondrial genome in the Yorkshire pig. Sequence analysis indicates that the genome structure is in accordance with other pig breeds, and it contains 22 tRNA genes, 2 ribosomal RNA genes, 13 protein-coding genes and 1 control region (D-loop region). The complete mitochondrial genome sequence of the Yorkshire pig provides an important record set for further study on genetic mechanism.

  1. On the sensitivity analysis of separated-loop MRS data

    NASA Astrophysics Data System (ADS)

    Behroozmand, A.; Auken, E.; Fiandaca, G.

    2013-12-01

    that of the conventional coincident-loop sounding. 2) The posterior parameter determination of central-loop MRS data is studied in a joint MRS and TEM data analysis scheme. The MRS kernel is the function that describes the spatial distribution of the sensitivity of the MRS measurement and, for given site specifications, depends on Q. In the typical 1D earth parametrization, a complete MRS measurement forms the 1D MRS kernel as a function of depth and Q; here referred to as a 1D kernel structure. For the conventional coincident-loop configuration, the 1D kernel structure covers the excited earth's volume throughout the applied Qs. As a result, the shallower parts of the subsurface are mainly sampled using smaller Qs and the deeper parts are mainly sampled using higher Qs. Here we also study the sensitivity kernel of the separated-loop MRS configuration, i.e. when different loops are used for transmitting the current and receiving the signal, and highlight the cases where an increased excited earth's volume is sampled throughout the Qs. We examined the optimal geometry of the receiver loop and the conditions under which a separate receiver system can be used are addressed. The results of this study suggest that it can be beneficial to develop MRS instrumentation where the receiver system is separated from the transmitter system.

  2. Performance analyses for fast variable optical attenuator-based optical current transformer

    NASA Astrophysics Data System (ADS)

    Wei, Pu; Chen, Chen; Wang, Xuefeng; Shan, Xuekang; Sun, Xiaohan

    2014-06-01

    In this paper, we analyze the performance of the electro-optic hybrid optical current transformer (HOCT) proposed by ourselves for high-voltage metering and protective relaying application. The transformer makes use of a fast variable optical attenuator (FVOA) to modulate the lightwave according to the voltage from the primary current sensor, such as low-power current transformer (LPCT). In order to improve the performance of the transformer, we use an optic-electro feedback loop with the PID control algorithm to compensate the nonlinearity of the FVOA. The linearity and accuracy of the transformer were analyzed and tested. The results indicate that the nonlinearity of the FVOA is completely compensated by the loop and the ratio and phase errors are under 0.07% and 5 minutes respectively, under the working power of less than 1 mW power. The transformer can be immune to the polarization and wavelength drift, and also robust against the environmental interference.

  3. Evolution in a Braided Loop Ensemble

    NASA Video Gallery

    This braided loop has several loops near the 'base' that appear to be unwinding with significant apparent outflow. This is evidence of untwisting, and the braided structure also seeming to unwind w...

  4. Bootstrapping a Five-Loop Amplitude Using Steinmann Relations.

    PubMed

    Caron-Huot, Simon; Dixon, Lance J; McLeod, Andrew; von Hippel, Matt

    2016-12-09

    The analytic structure of scattering amplitudes is restricted by Steinmann relations, which enforce the vanishing of certain discontinuities of discontinuities. We show that these relations dramatically simplify the function space for the hexagon function bootstrap in planar maximally supersymmetric Yang-Mills theory. Armed with this simplification, along with the constraints of dual conformal symmetry and Regge exponentiation, we obtain the complete five-loop six-particle amplitude.

  5. Optimum design of hybrid phase locked loops

    NASA Technical Reports Server (NTRS)

    Lee, P.; Yan, T.

    1981-01-01

    The design procedure of phase locked loops is described in which the analog loop filter is replaced by a digital computer. Specific design curves are given for the step and ramp input changes in phase. It is shown that the designed digital filter depends explicitly on the product of the sampling time and the noise bandwidth of the phase locked loop. This technique of optimization can be applied to the design of digital analog loops for other applications.

  6. Fragmentation of cosmic-string loops

    NASA Technical Reports Server (NTRS)

    York, Thomas

    1989-01-01

    The fragmentation of cosmic string loops is discussed, and the results of a simulation of this process are presented. The simulation can evolve any of a large class of loops essentially exactly, including allowing fragments that collide to join together. Such reconnection enhances the production of small fragments, but not drastically. With or without reconnections, the fragmentation process produces a collection of nonself-intersecting loops whose typical length is on the order of the persistence length of the initial loop.

  7. CURRENT STATUS OF INSTRUMENTATION FOR A FLUORIDE SALT HEAT TRANSPORT DEMONSTRATION LOOP

    SciTech Connect

    Kisner, Roger A; Holcomb, David Eugene

    2010-01-01

    A small forced convection liquid fluoride salt loop is under construction at Oak Ridge National Laboratory (ORNL) to examine the heat transfer behavior of FLiNaK in a heated pebble bed. Loop operation serves several purposes: (1) reestablishing the infrastructure necessary for fluoride salt loop testing, (2) demonstrating a wireless heating technique for simulating pebble type fuel, (3) demonstration of the integration of silicon carbide (SiC) and metallic components into a liquid salt loop, and (4) demonstration of the functionality of distinctive instrumentation required for liquid fluoride salts. Loop operation requires measurement of a broad set of process variables including temperature, flow, pressure, and level. Coolant chemistry measurements (as a corrosion indicator) and component health monitoring are also important for longer-term operation. Two dominating factors in sensor and instrument selection are the high operating temperature of the salt and its chemical environment.

  8. Teachers' Perception of Looping in Secondary Schools

    ERIC Educational Resources Information Center

    Chakey, Dennis J.

    2014-01-01

    The purpose of this qualitative study was to gain an understanding of secondary teachers' perception of the looping process. The research questions revealed teachers' opinions of the looping process and its impact on the overall educational experience. Participants within this study had experiences teaching within the looping process and within a…

  9. Data-aided carrier tracking loops

    NASA Technical Reports Server (NTRS)

    Lindsey, W. C.; Simon, M. K.

    1973-01-01

    Power in composite signal sidebands is used to enhance signal-to-noise ratio in carrier tracking loop, thereby reducing radio loss and decreasing probability of receiver error. By adding quadrature channel to phase-lock-loop detector circuit of receiver, dc component can be fed back into carrier tracking loop.

  10. A Novel Controller for Model with Combined LFC and AVR Loops of Single Area Power System

    NASA Astrophysics Data System (ADS)

    Gupta, Monika; Srivastava, Smriti; Gupta, J. R. P.

    2016-03-01

    In this study, a novel controller is designed to study low frequency oscillations for load frequency control (LFC) and voltage control of a single area power system. For more accuracy in dynamic and steady state responses, mutual effects between LFC and automatic voltage regulation (AVR) loops are investigated in a combined simulink model of LFC and AVR loops. The effectiveness of the proposed controller is first simulated on model with LFC loop alone. The proposed controller is a hybrid of neural network and fast traversal filters. The proposed hybrid controller requires less number of samples for training of weights, thus making the system fast. To study the coupling effects of AVR and LFC loops, dynamic performance of a complete system model for low frequency oscillation studies comprising of mechanical and electrical loops is done with the proposed controller.

  11. Loop connectors in dentogenic diastema

    PubMed Central

    Nayar, Sanjna; Jayesh, Raghevendra; Venkateshwaran; Dinakarsamy, V.

    2015-01-01

    Patients with a missing tooth along with diastema have limited treatment options to restore the edentulous space. The use of a conventional fixed partial denture (FPD) to replace the missing tooth may result in too wide anterior teeth leading to poor esthetics. Loss of anterior teeth with existing diastema may result in excess space available for pontic. This condition presents great esthetic challenge for prosthodontist. If implant supported prosthesis is not possible because of inadequate bone support, FPD along with loop connector may be a treatment option to maintain the diastema and provide optimal esthetic restoration. Here, we report a clinical case where FPD along with loop connector was used to achieve esthetic rehabilitation in maxillary anterior region in which midline diastema has been maintained. PMID:26015732

  12. Microgyroscope with closed loop output

    NASA Technical Reports Server (NTRS)

    Challoner, A. Dorian (Inventor); Gutierrez, Roman C. (Inventor); Tang, Tony K. (Inventor); Cargille, Donald R. (Inventor)

    2002-01-01

    A micro-gyroscope (10) having closed loop operation by a control voltage (V.sub.TY), that is demodulated by an output signal of the sense electrodes (S1, S2), providing Coriolis torque rebalance to prevent displacement of the micro-gyroscope (10) on the output axis (y-axis). The present invention provides wide-band, closed-loop operation for a micro-gyroscope (10) and allows the drive frequency to be closely tuned to a high Q sense axis resonance. A differential sense signal (S1-S2) is compensated and fed back by differentially changing the voltage on the drive electrodes to rebalance Coriolis torque. The feedback signal is demodulated in phase with the drive axis signal (K.sub..omega..crclbar..sub.x) to produce a measure of the Coriolis force.

  13. Grain boundary loops in graphene

    NASA Astrophysics Data System (ADS)

    Cockayne, Eric; Rutter, Gregory M.; Guisinger, Nathan P.; Crain, Jason N.; First, Phillip N.; Stroscio, Joseph A.

    2011-05-01

    Topological defects can affect the physical properties of graphene in unexpected ways. Harnessing their influence may lead to enhanced control of both material strength and electrical properties. Here we present a class of topological defects in graphene composed of a rotating sequence of dislocations that close on themselves, forming grain boundary loops that either conserve the number of atoms in the hexagonal lattice or accommodate vacancy or interstitial reconstruction, while leaving no unsatisfied bonds. One grain boundary loop is observed as a “flower” pattern in scanning tunneling microscopy studies of epitaxial graphene grown on SiC(0001). We show that the flower defect has the lowest energy per dislocation core of any known topological defect in graphene, providing a natural explanation for its growth via the coalescence of mobile dislocations.

  14. DNA Looping, Supercoiling and Tension

    NASA Astrophysics Data System (ADS)

    Finzi, Laura

    2007-11-01

    In complex organisms, activation or repression of gene expression by proteins bound to enhancer or silencer elements located several kilobases away from the promoter is a well recognized phenomenon. However, a mechanistic understanding of any of these multiprotein interactions is still incomplete. Part of the difficulty in characterizing long-range interactions is the complexity of the regulatory systems and also an underestimation of the effect of DNA supercoiling and tension. Supercoiling is expected to promote interactions between DNA sites because it winds the DNA into compact plectonemes in which distant DNA segments more frequently draw close. The idea that DNA is also under various levels of tension is becoming more widely accepted. Forces that stretch the double helix in vivo are the electrostatic repulsion among the negatively charged phosphate groups along the DNA backbone, the action of motor enzymes perhaps acting upon a topologically constrained sequence of DNA or chromosome segregation during cell mitosis following DNA replication. Presently, little is known about the tension acting on DNA in vivo, but characterization of how physiological regulatory processes, such as loop formation, depend on DNA tension in vitro will indicate the stretching force regimes likely to exist in vivo. In this light, the well studied CI protein of bacteriophage l, which was recently found to cause a of 3.8 kbp loop in DNA, is an ideal system in which to characterize long-range gene regulation. The large size of the loop lends itself to single-molecule techniques, which allow characterization of the dynamics of CI-mediated l DNA looping under controlled levels of supercoiling and tension. Such experiments are being used to discover the principles of long-range interactions in l and in more complex systems.

  15. Loops in inflationary correlation functions

    NASA Astrophysics Data System (ADS)

    Tanaka, Takahiro; Urakawa, Yuko

    2013-12-01

    We review the recent progress regarding the loop corrections to the correlation functions in the inflationary universe. A naive perturbation theory predicts that the loop corrections generated during inflation suffer from various infrared (IR) pathologies. Introducing an IR cutoff by hand is neither satisfactory nor enough to fix the problem of a secular growth, which may ruin the predictive power of inflation models if the inflation lasts sufficiently long. We discuss the origin of the IR divergences and explore the regularity conditions of the loop corrections for the adiabatic perturbation, the iso-curvature perturbation, and the tensor perturbation, in turn. These three kinds of perturbations have qualitative differences, but in discussing the IR regularity there is a feature common to all cases, which is the importance of the proper identification of observable quantities. Genuinely, observable quantities should respect the gauge invariance from the view point of a local observer. Interestingly, we find that the requirement of the IR regularity restricts the allowed quantum states.

  16. Beyond FASFA Completion

    ERIC Educational Resources Information Center

    Castleman, Ben; Page, Lindsay

    2015-01-01

    The Free Application for Federal Student Aid (FAFSA)--which students must complete to qualify for most federal, state, and institutional financial aid--is a gateway to college through which many students must pass, particularly those from low- to moderate-income households (King, 2004; Kofoed, 2013). Yet given the complexity of the…

  17. Making College Completion Personal

    ERIC Educational Resources Information Center

    Thomas, Heather

    2011-01-01

    There are countless justifications for why young adults, faced with so many distractions, do not complete their educations. Many students fail to finish college because of a lack of information and understanding about healthy relationships and sex education. The author's own struggles and eventual successes as a student and mother compelled her to…

  18. College Completion Tool Kit

    ERIC Educational Resources Information Center

    US Department of Education, 2011

    2011-01-01

    In March, 2009, President Obama proposed the American Graduation Initiative, which established the goal that by 2020 the United States will regain its position as the nation with the highest percentage of its population holding post-secondary degrees and credentials. The College Completion Toolkit provides information that governors and other…

  19. Completing a Simple Circuit.

    ERIC Educational Resources Information Center

    Slater, Timothy F.; Adams, Jeffrey P.; Brown, Thomas R.

    2000-01-01

    Students have problems successfully arranging an electric circuit to make the bulb produce light. Investigates the percentage of students able to complete a circuit with a given apparatus, and the effects of prior experience on student success. Recommends hands-on activities at the elementary and secondary school levels. (Contains 14 references.)…

  20. Direct numerical approach to one-loop amplitudes

    NASA Astrophysics Data System (ADS)

    Duplančić, G.; Klajn, B.

    2017-01-01

    We present a completely numerical method of calculating one-loop amplitudes. Our approach is built upon two different existing methods: the contour deformation and the extrapolation methods. Taking the best features of each of them, we devise an intuitive, stable and robust procedure which circumvents the problem of large cancellations and related numerical instabilities by calculating the complete amplitude at once. As a proof of concept, we use our method to calculate the 2 γ →(N -2 )γ benchmark process, as well as the Higgs decay amplitude H →γ γ .

  1. Exotic Twisted Equivariant Cohomology of Loop Spaces, Twisted Bismut-Chern Character and T-Duality

    NASA Astrophysics Data System (ADS)

    Han, Fei; Mathai, Varghese

    2015-07-01

    We define exotic twisted - equivariant cohomology for the loop space LZ of a smooth manifold Z via the invariant differential forms on LZ with coefficients in the (typically non-flat) holonomy line bundle of a gerbe, with differential an equivariantly flat superconnection. We introduce the twisted Bismut-Chern character form, a loop space refinement of the twisted Chern character form in Bouwknegt et al. (Commun Math Phys 228:17-49, 2002) and Mathai and Stevenson (Commun Math Phys 236:161-186, 2003), which represents classes in the completed periodic exotic twisted -equivariant cohomology of LZ.We establish a localisation theorem for the completed periodic exotic twisted -equivariant cohomology for loop spaces and apply it to establish T-duality in a background flux in type II String Theory from a loop space perspective.

  2. Automatic loop steering for directional drilling

    SciTech Connect

    Patten, W.N.; Kuehn, J.L.; Ziaja, M.B.

    1994-12-31

    A closed loop controller design for the steering of directed drilling is proposed in the paper. The paper first describes the development of a causal model of the directed drilling process that consists of two critical components. First a closed form bottom hole assembly (BHA) model is described. The BHA model makes it possible to solve the `inverse` problem on-line in real time. That is, having measured the `shape` of the compliant BHA at any instant, the real time BHA model will be used to determine both the exact location and orientation of the bit in a global reference frame and boundary conditions of the BHA at the rock/bit interface. Those boundary conditions include the instantaneous values of the net forces and moments at the rock/bit interface. Secondly, the paper describes a proposed input-output rock/bit interaction (RBI) model that can be shown to accurately determine the directional tendency of the bit on-line. The model structure is consistent with the models proposed by Ho (1987) and Rafie (1988) in the case when a constant build/drop rate is achieved. The model is shown to mimic field data which was published by Jogi et al (1988). The BHA and RBI models are then combined to yield a continuous differential model of the drilling process. It is assumed that force inputs to the BHA are obtained from continuously variable eccentric stabilizers in the BHA near the bit. A closed loop steering control algorithm is designed around the proposed drilling process model (DPM). Finally, simulations of the controlled DPM and an uncontrolled building BHA are compared to demonstrate the feasibility of the automatic steering controller.

  3. Effective loop quantum geometry of Schwarzschild interior

    NASA Astrophysics Data System (ADS)

    Cortez, Jerónimo; Cuervo, William; Morales-Técotl, Hugo A.; Ruelas, Juan C.

    2017-03-01

    The success of loop quantum cosmology to resolve classical singularities of homogeneous models has led to its application to the classical Schwarszchild black hole interior, which takes the form of a homogeneous Kantowski-Sachs model. The first steps of this were done in pure quantum mechanical terms, hinting at the traversable character of the would-be classical singularity, and then others were performed using effective heuristic models capturing quantum effects that allowed a geometrical description closer to the classical one but avoided its singularity. However, the problem of establishing the link between the quantum and effective descriptions was left open. In this work, we propose to fill in this gap by considering the path-integral approach to the loop quantization of the Kantowski-Sachs model corresponding to the Schwarzschild black hole interior. We show that the transition amplitude can be expressed as a path integration over the imaginary exponential of an effective action which just coincides, under some simplifying assumptions, with the heuristic one. Additionally, we further explore the consequences of the effective dynamics. We prove first that such dynamics imply some rather simple bounds for phase-space variables, and in turn—remarkably, in an analytical way—they imply that various phase-space functions that were singular in the classical model are now well behaved. In particular, the expansion rate, its time derivative, and the shear become bounded, and hence the Raychaudhuri equation is finite term by term, thus resolving the singularities of classical geodesic congruences. Moreover, all effective scalar polynomial invariants turn out to be bounded.

  4. Monitoring Digital Closed-Loop Feedback Systems

    NASA Technical Reports Server (NTRS)

    Katz, Richard; Kleyner, Igor

    2011-01-01

    A technique of monitoring digital closed-loop feedback systems has been conceived. The basic idea is to obtain information on the performances of closed-loop feedback circuits in such systems to aid in the determination of the functionality and integrity of the circuits and of performance margins. The need for this technique arises as follows: Some modern digital systems include feedback circuits that enable other circuits to perform with precision and are tolerant of changes in environment and the device s parameters. For example, in a precision timing circuit, it is desirable to make the circuit insensitive to variability as a result of the manufacture of circuit components and to the effects of temperature, voltage, radiation, and aging. However, such a design can also result in masking the indications of damaged and/or deteriorating components. The present technique incorporates test circuitry and associated engineering-telemetry circuitry into an embedded system to monitor the closed-loop feedback circuits, using spare gates that are often available in field programmable gate arrays (FPGAs). This technique enables a test engineer to determine the amount of performance margin in the system, detect out of family circuit performance, and determine one or more trend(s) in the performance of the system. In one system to which the technique has been applied, an ultra-stable oscillator is used as a reference for internal adjustment of 12 time-to-digital converters (TDCs). The feedback circuit produces a pulse-width-modulated signal that is fed as a control input into an amplifier, which controls the circuit s operating voltage. If the circuit s gates are determined to be operating too slowly or rapidly when their timing is compared with that of the reference signal, then the pulse width increases or decreases, respectively, thereby commanding the amplifier to increase or reduce, respectively, its output level, and "adjust" the speed of the circuits. The nominal

  5. Multi-loop decentralized PID control based on covariance control criteria: an LMI approach.

    PubMed

    Huang, Xin; Huang, Biao

    2004-01-01

    PID control is well known and widely applied in industry and many design algorithms are readily available in the literature. However, systematic design of multi-loop or decentralized PID control for multivariable processes to meet certain objectives simultaneously is still a challenging task. Designing multi-loop PID controllers such that the process variables satisfy the generalized covariance constraints is studied in this paper. A convergent computational algorithm is proposed to calculate the multi-loop PID controller for a process with stable disturbances. This algorithm is then extended to a process with random-walk disturbances. The feasibility of the proposed algorithm is verified by applying it to several simulation examples.

  6. Dynamic Aperture-based Solar Loop Segmentation

    NASA Technical Reports Server (NTRS)

    Lee, Jon Kwan; Newman, Timothy S.; Gary, G. Allen

    2006-01-01

    A new method to automatically segment arc-like loop structures from intensity images of the Sun's corona is introduced. The method constructively segments credible loop structures by exploiting the Gaussian-like shape of loop cross-sectional intensity profiles. The experimental results show that the method reasonably segments most of the well-defined loops in coronal images. The method is only the second published automated solar loop segmentation method. Its advantage over the other published method is that it operates independently of supplemental time specific data.

  7. Modeling Phase-Locked Loops Using Verilog

    DTIC Science & Technology

    2007-11-01

    a charge pump, the phase detector has a tri-state output that can drive a opamp loop filter directly. This signal is conditioned by the charge pump...then it can directly drive an opamp based loop filter. Most loop filters are based upon an integrator loop. The integrator loop filter is advantageous...replaced with an accumulator. The opamp circuit can be replaced by a digital filter using Z-transform theory z=exp(jwT), where T is the sampling

  8. Revisiting antibody modeling assessment for CDR-H3 loop

    PubMed Central

    Nishigami, Hiroshi; Kamiya, Narutoshi; Nakamura, Haruki

    2016-01-01

    The antigen-binding site of antibodies, also known as complementarity-determining region (CDR), has hypervariable sequence properties. In particular, the third CDR loop of the heavy chain, CDR-H3, has such variability in its sequence, length, and conformation that ordinary modeling techniques cannot build a high-quality structure. At Stage 2 of the Second Antibody Modeling Assessment (AMA-II) held in 2013, the model structures of the CDR-H3 loops were submitted by the seven modelers and were critically assessed. After our participation in AMA-II, we rebuilt one of the long CDR-H3 loops with 13 residues (A52 antibody) by a more precise method, using enhanced conformational sampling with the explicit water model, as compared to our previous method employed at AMA-II. The current stable models obtained from the free energy landscape at 300 K include structures similar to the X-ray crystal structures. Those models were not built in our previous work at AMA-II. The current free energy landscape suggested that the CDR-H3 loop structures in the crystal are not stable in solution, but they are stabilized by the crystal packing effect. PMID:27515703

  9. Completeness of CPSA

    DTIC Science & Technology

    2011-10-01

    is weakly solved in F ′ by σ, if and only if p is solved in F ′ by σ, or if • Sol5. There is an element of Targ (Esc(F ′, e′p), e′p)) not in σ( Targ (E...of pp is a variable not of sort mesg and tt = ep or (ii) the endpoint of pp is a variable of sort mesg and tt ∈ Targ (Esc(F , ep), ep). • S0 is a set... Targ (Esc(F1, ep)). 9.4 The Cohort and the CPSA Set Reduction First, we define the cohort, the top-level suite used in the cpsa algorithm. Definition 9.16

  10. Hyperstaticity and loops in frictional granular packings

    NASA Astrophysics Data System (ADS)

    Tordesillas, Antoinette; Lam, Edward; Metzger, Philip T.

    2009-06-01

    The hyperstatic nature of granular packings of perfectly rigid disks is analyzed algebraically and through numerical simulation. The elementary loops of grains emerge as a fundamental element in addressing hyperstaticity. Loops consisting of an odd number of grains behave differently than those with an even number. For odd loops, the latent stresses are exterior and are characterized by the sum of frictional forces around each loop. For even loops, the latent stresses are interior and are characterized by the alternating sum of frictional forces around each loop. The statistics of these two types of loop sums are found to be Gibbsian with a "temperature" that is linear with the friction coefficient μ when μ<1.

  11. High-temperature helium-loop facility

    SciTech Connect

    Tokarz, R.D.

    1981-09-01

    The high-temperature helium loop is a facility for materials testing in ultrapure helium gas at high temperatures. The closed loop system is capable of recirculating high-purity helium or helium with controlled impurities. The gas loop maximum operating conditions are as follows: 300 psi pressure, 500 lb/h flow rate, and 2100/sup 0/F temperature. The two test sections can accept samples up to 3.5 in. diameter and 5 ft long. The gas loop is fully instrumented to continuously monitor all parameters of loop operation as well as helium impurities. The loop is fully automated to operate continuously and requires only a daily servicing by a qualified operator to replenish recorder charts and helium makeup gas. Because of its versatility and high degree of parameter control, the helium loop is applicable to many types of materials research. This report describes the test apparatus, operating parameters, peripheral systems, and instrumentation system.

  12. Chemical Looping Technology: Oxygen Carrier Characteristics.

    PubMed

    Luo, Siwei; Zeng, Liang; Fan, Liang-Shih

    2015-01-01

    Chemical looping processes are characterized as promising carbonaceous fuel conversion technologies with the advantages of manageable CO2 capture and high energy conversion efficiency. Depending on the chemical looping reaction products generated, chemical looping technologies generally can be grouped into two types: chemical looping full oxidation (CLFO) and chemical looping partial oxidation (CLPO). In CLFO, carbonaceous fuels are fully oxidized to CO2 and H2O, as typically represented by chemical looping combustion with electricity as the primary product. In CLPO, however, carbonaceous fuels are partially oxidized, as typically represented by chemical looping gasification with syngas or hydrogen as the primary product. Both CLFO and CLPO share similar operational features; however, the optimum process configurations and the specific oxygen carriers used between them can vary significantly. Progress in both CLFO and CLPO is reviewed and analyzed with specific focus on oxygen carrier developments that characterize these technologies.

  13. Systematic U(1 ) B - L extensions of loop-induced neutrino mass models with dark matter

    NASA Astrophysics Data System (ADS)

    Ho, Shu-Yu; Toma, Takashi; Tsumura, Koji

    2016-08-01

    We study the gauged U(1 ) B - L extensions of the models for neutrino masses and dark matter. In this class of models, tiny neutrino masses are radiatively induced through the loop diagrams, while the origin of the dark matter stability is guaranteed by the remnant of the gauge symmetry. Depending on how the lepton number conservation is violated, these models are systematically classified. We present complete lists for the one-loop Z2 and the two-loop Z3 radiative seesaw models as examples of the classification. The anomaly cancellation conditions in these models are also discussed.

  14. Master integrals for the four-loop Sudakov form factor

    NASA Astrophysics Data System (ADS)

    Boels, Rutger H.; Kniehl, Bernd A.; Yang, Gang

    2016-01-01

    The light-like cusp anomalous dimension is a universal function in the analysis of infrared divergences. In maximally (N = 4) supersymmetric Yang-Mills theory (SYM) in the planar limit, it is known, in principle, to all loop orders. The non-planar corrections are not known in any theory, with the first appearing at the four-loop order. The simplest quantity which contains this correction is the four-loop two-point form factor of the stress tensor multiplet. This form factor was largely obtained in integrand form in a previous work for N = 4 SYM, up to a free parameter. In this work, a reduction of the appearing integrals obtained by solving integration-by-parts (IBP) identities using a modified version of Reduze is reported. The form factor is shown to be independent of the remaining parameter at integrand level due to an intricate pattern of cancellations after IBP reduction. Moreover, two of the integral topologies vanish after reduction. The appearing master integrals are cross-checked using independent algebraic-geometry techniques explored in the Mint package. The latter results provide the basis of master integrals applicable to generic form factors, including those in Quantum Chromodynamics. Discrepancies between explicitly solving the IBP relations and the MINT approach are highlighted. Remaining bottlenecks to completing the computation of the four-loop non-planar cusp anomalous dimension in N = 4 SYM and beyond are identified.

  15. Bootstrapping Multi-Parton Loop Amplitudes in QCD

    SciTech Connect

    Bern, Zvi; Dixon, Lance J.; Kosower, David A.; /Saclay, SPhT

    2005-07-06

    The authors present a new method for computing complete one-loop amplitudes, including their rational parts, in non-supersymmetric gauge theory. This method merges the unitarity method with on-shell recursion relations. It systematizes a unitarity-factorization bootstrap approach previously applied by the authors to the one-loop amplitudes required for next-to-leading order QCD corrections to the processes e{sup +}e{sup -} {yields} Z, {gamma}* {yields} 4 jets and pp {yields} W + 2 jets. We illustrate the method by reproducing the one-loop color-ordered five-gluon helicity amplitudes in QCD that interfere with the tree amplitude, namely A{sub 5;1}(1{sup -}, 2{sup -}, 3{sup +}, 4{sup +}, 5{sup +}) and A{sub 5;1}(1{sup -}, 2{sup +}, 3{sup -}, 4{sup +}, 5{sup +}). Then we describe the construction of the six- and seven-gluon amplitudes with two adjacent negative-helicity gluons, A{sub 6;1}(1{sup -}, 2{sup -}, 3{sup +}, 4{sup +}, 5{sup +}, 6{sup +}) and A{sub 7;1}(1{sup -}, 2{sup -}, 3{sup +}, 4{sup +}, 5{sup +}, 6{sup +}, 7{sup +}), which uses the previously-computed logarithmic parts of the amplitudes as input. They present a compact expression for the six-gluon amplitude. No loop integrals are required to obtain the rational parts.

  16. A cut-off tubular geometry of loop space

    NASA Astrophysics Data System (ADS)

    Mukhopadhyay, Partha

    Motivated by the computation of loop space quantum mechanics as indicated in [14], here we seek a better understanding of the tubular geometry of loop space ℒℳ corresponding to a Riemannian manifold ℳ around the submanifold of vanishing loops. Our approach is to first compute the tubular metric of (ℳ2N+1) C around the diagonal submanifold, where (ℳN) C is the Cartesian product of N copies of ℳ with a cyclic ordering. This gives an infinite sequence of tubular metrics such that the one relevant to ℒℳ can be obtained by taking the limit N →∞. Such metrics are computed by adopting an indirect method where the general tubular expansion theorem of [21] is crucially used. We discuss how the complete reparametrization isometry of loop space arises in the large-N limit and verify that the corresponding Killing equation is satisfied to all orders in tubular expansion. These tubular metrics can alternatively be interpreted as some natural Riemannian metrics on certain bundles of tangent spaces of ℳ which, for ℳ×ℳ, is the tangent bundle Tℳ.

  17. Complete atrioventricular block in Duchenne muscular dystrophy.

    PubMed

    Fayssoil, A; Orlikowski, D; Nardi, O; Annane, D

    2008-11-01

    Duchenne muscular dystrophy (DMD) is an inherited myogenic disorder due to mutations in the dystrophin gene on chromosome Xp21.1. It is characterized by progressive muscle wasting and weakness of variable distribution and severity. Heart is involved leading to heart failure. Conduction abnormalities are unusual. We report a case of complete atrio-ventricular block in a DMD patient.

  18. Image Zoom Completion.

    PubMed

    Hidane, Moncef; El Gheche, Mireille; Aujol, Jean-Francois; Berthoumieu, Yannick; Deledalle, Charles-Alban

    2016-08-01

    We consider the problem of recovering a high-resolution image from a pair consisting of a complete low-resolution image and a high-resolution but incomplete one. We refer to this task as the image zoom completion problem. After discussing possible contexts in which this setting may arise, we introduce a nonlocal regularization strategy, giving full details concerning the numerical optimization of the corresponding energy and discussing its benefits and shortcomings. We also derive two total variation-based algorithms and evaluate the performance of the proposed methods on a set of natural and textured images. We compare the results and get with those obtained with two recent state-of-the-art single-image super-resolution algorithms.

  19. SRS SWPF Construction Completion

    SciTech Connect

    Craig, Jack; Sheppard, Frank; Marks, Pam

    2016-08-04

    Now that construction is complete, DOE and construction contractor Parsons, are focusing on testing the Savannah River Site’s Salt Waste Processing Facility (SWPF) systems and training the workforce to operate the plant in preparation for the start of operations. Once in operation, the SWPF will significantly increase processing rates at SRS tank farms in an effort to empty the site’s high-level radioactive waste tanks.

  20. SRS SWPF Construction Completion

    ScienceCinema

    Craig, Jack; Sheppard, Frank; Marks, Pam

    2016-08-17

    Now that construction is complete, DOE and construction contractor Parsons, are focusing on testing the Savannah River Site’s Salt Waste Processing Facility (SWPF) systems and training the workforce to operate the plant in preparation for the start of operations. Once in operation, the SWPF will significantly increase processing rates at SRS tank farms in an effort to empty the site’s high-level radioactive waste tanks.

  1. Development of variable-width ribbon heating elements for liquid-metal and gas-cooled fast breeder reactor fuel-pin simulators

    SciTech Connect

    McCulloch, R.W.; Post, D.W.; Lovell, R.T.; Snyder, S.D.

    1981-04-01

    Variable-width ribbon heating elements that provide a chopped-cosine variable heat flux profile have been fabricated for fuel pin simulators used in test loops by the Breeder Reactor Program Thermal-Hydraulic Out-of-Reactor Safety test facility and the Gas-Cooled Fast Breeder Reactor-Core Flow Test Loop. Thermal, mechanical, and electrical design considerations are used to derive an analytical expression that precisely describes ribbon contour in terms of the major fabrication parameters. These parameters are used to generate numerical control tapes that control ribbon cutting and winding machines. Infrared scanning techniques are developed to determine the optimum transient thermal profile of the coils and relate this profile to that generated by the coils in completed fuel pin simulators.

  2. An Insight to the Modeling of 1 × 1 Rib Loop Formation Process on Circular Weft Knitting Machine using Computer

    NASA Astrophysics Data System (ADS)

    Ray, Sadhan Chandra

    2015-10-01

    The mechanics of single jersey loop formation is well-reported is literature. However, as the concept of any model of double jersey loop formation process is not available in accessible international literature. Therefore, it was planned to develop a model of 1 × 1 rib loop formation process on dial and cylinder machine using computer so that the influence of various input variables on the final loop length as well on the profile of tension on the yarn inside Knitting Zone (KZ) can be understood. The model provides an insight into the mechanics of 1 × 1 rib loop formation system on dial and cylinder machine. Besides, the degree of agreement between predicted and measured values of loop length and cam forces as well as theoretical analysis of the model have justified the acceptability of the model.

  3. Dirac Loops in Carbon Allotropes

    NASA Astrophysics Data System (ADS)

    Mullen, Kieran; Uchoa, Bruno; Glatzhofer, D.

    2015-03-01

    We propose a family of structures that have ``Dirac loops'': closed lines in momentum space with Dirac-like quasiparticles, on which the density of states vanishes linearly with energy. The structures all possess the planar trigonal connectivity present in graphene, but are three dimensional. We discuss the consequences of their multiply-connected Fermi surface for transport, including the presence of three dimensional Integer Quantum Hall effect. In the presence of spin-orbit coupling, we show that those structures may have topological surface states. We discuss the feasibility of realizing the structures as an allotrope of carbon. Work supported by NSF Grants DMR-1310407 and DMR-1352604.

  4. Singularities in loop quantum cosmology.

    PubMed

    Cailleteau, Thomas; Cardoso, Antonio; Vandersloot, Kevin; Wands, David

    2008-12-19

    We show that simple scalar field models can give rise to curvature singularities in the effective Friedmann dynamics of loop quantum cosmology (LQC). We find singular solutions for spatially flat Friedmann-Robertson-Walker cosmologies with a canonical scalar field and a negative exponential potential, or with a phantom scalar field and a positive potential. While LQC avoids big bang or big rip type singularities, we find sudden singularities where the Hubble rate is bounded, but the Ricci curvature scalar diverges. We conclude that the effective equations of LQC are not in themselves sufficient to avoid the occurrence of curvature singularities.

  5. Transcranial brain stimulation: closing the loop between brain and stimulation

    PubMed Central

    Karabanov, Anke; Thielscher, Axel; Siebner, Hartwig Roman

    2016-01-01

    Purpose of review To discuss recent strategies for boosting the efficacy of noninvasive transcranial brain stimulation to improve human brain function. Recent findings Recent research exposed substantial intra- and inter-individual variability in response to plasticity-inducing transcranial brain stimulation. Trait-related and state-related determinants contribute to this variability, challenging the standard approach to apply stimulation in a rigid, one-size-fits-all fashion. Several strategies have been identified to reduce variability and maximize the plasticity-inducing effects of noninvasive transcranial brain stimulation. Priming interventions or paired associative stimulation can be used to ‘standardize’ the brain-state and hereby, homogenize the group response to stimulation. Neuroanatomical and neurochemical profiling based on magnetic resonance imaging and spectroscopy can capture trait-related and state-related variability. Fluctuations in brain-states can be traced online with functional brain imaging and inform the timing or other settings of transcranial brain stimulation. State-informed open-loop stimulation is aligned to the expression of a predefined brain state, according to prespecified rules. In contrast, adaptive closed-loop stimulation dynamically adjusts stimulation settings based on the occurrence of stimulation-induced state changes. Summary Approaches that take into account trait-related and state-related determinants of stimulation-induced plasticity bear considerable potential to establish noninvasive transcranial brain stimulation as interventional therapeutic tool. PMID:27224087

  6. Complete thoracic ectopia cordis.

    PubMed

    Alphonso, N; Venugopal, P S; Deshpande, R; Anderson, D

    2003-03-01

    Thoracic ectopia cordis is a rare congenital defect with very few reported survivors after surgical correction. We report a case of complete thoracic ectopia cordis with double outlet right ventricle. The diagnosis was established antenatally and a repair was undertaken soon after birth. The child remained stable and was extubated on the fifth post-operative day. Forty-eight hours later the child succumbed to an unexplained respiratory arrest. Also presented is a review of the different surgical strategies for this unusual condition.

  7. Complete Androgen Insensitivity Syndrome.

    PubMed

    Hashmi, Asra; Hanif, Farha; Hanif, Shumaila Muhammad; Abdullah, Farhan Essa; Shamim, Muhammad Shahid

    2008-07-01

    The incidence of Complete Androgen Insensitivity Syndrome (CAIS) is about 1 in 20,000. People with CAIS are normal appearing females, despite the presence of testes and a 46, XY chromosome constitution. We came across a case in which a 17 years old girl presented with the complaint of inguinal hernia and amenorrhea. Subsequent investigations were done revealing absence of female internal genitalia and the presence of abdominal mass, possibly testes. Syndrome has been linked to mutations in AR, the gene for the human Androgen Receptor, located at Xq11-12 leading to the insensitivity of the receptor to testosterone. Gonadectomy was performed and life long Hormone replacement therapy was advised.

  8. Fabricating niobium test loops for the SP-100 space reactor

    NASA Technical Reports Server (NTRS)

    Bryhan, Anthony J.; Chan, Ricky C.

    1993-01-01

    This article describes the successful fabrication, operation, and evaluation of a series of niobium-alloy (Nb-1 Zr and PWC-11) thermal convection loops designed to contain and circulate molten lithium at 1,350 K. These loops were used to establish the fabrication variables of significance for a nuclear power supply for space. Approximately 200 weldments were evaluated for their tendency to be attacked by lithium as a function of varying atmospheric contamination. No attack occurred for any weldment free of contamination, with or without heat treatment, and no welds accidentally deviated from purity. The threshold oxygen content for weldment attack was determined to be 170-200 ppm. Attack varied directly with weldment oxygen and nitrogen contents.

  9. Functional Characterization of Antibodies against Neisseria gonorrhoeae Opacity Protein Loops

    PubMed Central

    Cole, Jessica G.; Jerse, Ann E.

    2009-01-01

    Background The development of a gonorrhea vaccine is challenged by the lack of correlates of protection. The antigenically variable neisserial opacity (Opa) proteins are expressed during infection and have a semivariable (SV) and highly conserved (4L) loop that could be targeted in a vaccine. Here we compared antibodies to linear (Ablinear) and cyclic (Abcyclic) peptides that correspond to the SV and 4L loops and selected hypervariable (HV2) loops for surface-binding and protective activity in vitro and in vivo. Methods/Findings AbSV cyclic bound a greater number of different Opa variants than AbSV linear, including variants that differed by seven amino acids. Antibodies to the 4L peptide did not bind Opa-expressing bacteria. AbSV cyclic and AbHV2 cyclic, but not AbSV linear or AbHV2 linear agglutinated homologous Opa variants, and AbHV2BD cyclic but not AbHV2BD linear blocked the association of OpaB variants with human endocervical cells. Only AbHV2BD linear were bactericidal against the serum resistant parent strain. Consistent with host restrictions in the complement cascade, the bactericidal activity of AbHV2BD linear was increased 8-fold when rabbit complement was used. None of the antibodies was protective when administered vaginally to mice. Antibody duration in the vagina was short-lived, however, with <50% of the antibodies recovered 3 hrs post-administration. Conclusions We conclude that an SV loop-specific cyclic peptide can be used to induce antibodies that recognize a broad spectrum of antigenically distinct Opa variants and have agglutination abilities. HV2 loop-specific cyclic peptides elicited antibodies with agglutination and adherence blocking abilities. The use of human complement when testing the bactericidal activity of vaccine-induced antibodies against serum resistant gonococci is also important. PMID:19956622

  10. Cardiovascular simulator improvement: pressure versus volume loop assessment.

    PubMed

    Fonseca, Jeison; Andrade, Aron; Nicolosi, Denys E C; Biscegli, José F; Leme, Juliana; Legendre, Daniel; Bock, Eduardo; Lucchi, Julio Cesar

    2011-05-01

    This article presents improvement on a physical cardiovascular simulator (PCS) system. Intraventricular pressure versus intraventricular volume (PxV) loop was obtained to evaluate performance of a pulsatile chamber mimicking the human left ventricle. PxV loop shows heart contractility and is normally used to evaluate heart performance. In many heart diseases, the stroke volume decreases because of low heart contractility. This pathological situation must be simulated by the PCS in order to evaluate the assistance provided by a ventricular assist device (VAD). The PCS system is automatically controlled by a computer and is an auxiliary tool for VAD control strategies development. This PCS system is according to a Windkessel model where lumped parameters are used for cardiovascular system analysis. Peripheral resistance, arteries compliance, and fluid inertance are simulated. The simulator has an actuator with a roller screw and brushless direct current motor, and the stroke volume is regulated by the actuator displacement. Internal pressure and volume measurements are monitored to obtain the PxV loop. Left chamber internal pressure is directly obtained by pressure transducer; however, internal volume has been obtained indirectly by using a linear variable differential transformer, which senses the diaphragm displacement. Correlations between the internal volume and diaphragm position are made. LabVIEW integrates these signals and shows the pressure versus internal volume loop. The results that have been obtained from the PCS system show PxV loops at different ventricle elastances, making possible the simulation of pathological situations. A preliminary test with a pulsatile VAD attached to PCS system was made.

  11. Insert tree completion system

    SciTech Connect

    Brands, K.W.; Ball, I.G.; Cegielski, E.J.; Gresham, J.S.; Saunders, D.N.

    1982-09-01

    This paper outlines the overall project for development and installation of a low-profile, caisson-installed subsea Christmas tree. After various design studies and laboratory and field tests of key components, a system for installation inside a 30-in. conductor was ordered in July 1978 from Cameron Iron Works Inc. The system is designed to have all critical-pressure-containing components below the mudline and, with the reduced profile (height) above seabed, provides for improved safety of satellite underwater wells from damage by anchors, trawl boards, and even icebergs. In addition to the innovative nature of the tree design, the completion includes improved 3 1/2-in. through flowline (TFL) pumpdown completion equipment with deep set safety valves and a dual detachable packer head for simplified workover capability. The all-hydraulic control system incorporates a new design of sequencing valve for both Christmas tree control and remote flowline connection. A semisubmersible drilling rig was used to initiate the first end flowline connection at the wellhead for subsequent tie-in to the prelaid, surface-towed, all-welded subsea pipeline bundle.

  12. The Intracellular Loop of the Glycine Receptor: It’s not all about the Size

    PubMed Central

    Langlhofer, Georg; Villmann, Carmen

    2016-01-01

    The family of Cys-loop receptors (CLRs) shares a high degree of homology and sequence identity. The overall structural elements are highly conserved with a large extracellular domain (ECD) harboring an α-helix and 10 β-sheets. Following the ECD, four transmembrane domains (TMD) are connected by intracellular and extracellular loop structures. Except the TM3–4 loop, their length comprises 7–14 residues. The TM3–4 loop forms the largest part of the intracellular domain (ICD) and exhibits the most variable region between all CLRs. The ICD is defined by the TM3–4 loop together with the TM1–2 loop preceding the ion channel pore. During the last decade, crystallization approaches were successful for some members of the CLR family. To allow crystallization, the intracellular loop was in most structures replaced by a short linker present in prokaryotic CLRs. Therefore, no structural information about the large TM3–4 loop of CLRs including the glycine receptors (GlyRs) is available except for some basic stretches close to TM3 and TM4. The intracellular loop has been intensively studied with regard to functional aspects including desensitization, modulation of channel physiology by pharmacological substances, posttranslational modifications, and motifs important for trafficking. Furthermore, the ICD interacts with scaffold proteins enabling inhibitory synapse formation. This review focuses on attempts to define structural and functional elements within the ICD of GlyRs discussed with the background of protein-protein interactions and functional channel formation in the absence of the TM3–4 loop. PMID:27330534

  13. External bulb variable volume maser

    NASA Technical Reports Server (NTRS)

    Reinhardt, V. S.; Cervenka, P. O. (Inventor)

    1978-01-01

    A maser functioning as a frequency standard stable to one part in 10 to the 14th power includes a variable volume, constant surface area storage bulb having a fixed volume portion located in a resonant cavity from which the frequency standard is derived. A variable volume portion of the bulb, exterior to the resonant cavity, has a maximum volume on the same order of magnitude as the fixed volume bulb portion. The cavity has a length to radius ratio of at least 3:1 so that the operation is attained without the need for a feedback loop. A baffle plate, between the fixed and variable volume bulb portions, includes apertures for enabling hydrogen atoms to pass between the two bulb portions and is an electromagnetic shield that prevents coupling of the electromagnetic field of the cavity into the variable volume bulb portion.

  14. Beyond complete positivity

    NASA Astrophysics Data System (ADS)

    Dominy, Jason M.; Lidar, Daniel A.

    2016-04-01

    We provide a general and consistent formulation for linear subsystem quantum dynamical maps, developed from a minimal set of postulates, primary among which is a relaxation of the usual, restrictive assumption of uncorrelated initial system-bath states. We describe the space of possibilities admitted by this formulation, namely that, far from being limited to only completely positive (CP) maps, essentially any C-linear, Hermiticity-preserving, trace-preserving map can arise as a legitimate subsystem dynamical map from a joint unitary evolution of a system coupled to a bath. The price paid for this added generality is a trade-off between the set of admissible initial states and the allowed set of joint system-bath unitary evolutions. As an application, we present a simple example of a non-CP map constructed as a subsystem dynamical map that violates some fundamental inequalities in quantum information theory, such as the quantum data processing inequality.

  15. Magnetic monopole in the loop representation

    SciTech Connect

    Leal, Lorenzo; Lopez, Alexander

    2006-01-15

    We quantize, within the Loop Representation formalism, the electromagnetic field in the presence of a static magnetic pole. It is found that the loop-dependent physical wave functionals of the quantum Maxwell theory become multivalued, through a topological phase factor depending on the solid angle subtended at the monopole by a surface bounded by the loop. It is discussed how this fact generalizes what occurs in ordinary quantum mechanics in multiply connected spaces.

  16. LMFBR with booster pump in pumping loop

    DOEpatents

    Rubinstein, H.J.

    1975-10-14

    A loop coolant circulation system is described for a liquid metal fast breeder reactor (LMFBR) utilizing a low head, high specific speed booster pump in the hot leg of the coolant loop with the main pump located in the cold leg of the loop, thereby providing the advantages of operating the main pump in the hot leg with the reliability of cold leg pump operation.

  17. Catheterization of Intestinal Loops in Ruminants Does Not Adversely Affect Loop Function

    PubMed Central

    Inglis, G Douglas; Kastelic, John P; Uwiera, Richard R E

    2010-01-01

    Catheterized intestinal loops may be a valuable model to elucidate key components of the host response to various treatments within the small intestine of ruminants. We examined whether catheterizing ileal loops in sheep affected the overall health of animals and intestinal function, whether a bacterial treatment could be introduced into the loops through the catheters, and whether broad-spectrum antibiotics could sterilize the loops. Escherichia coli cells transformed to express the GFP gene were introduced readily into the loops through the catheters, and GFP E. coli cells were localized within the injected loops. Catheterized loops, interspaces, and intact ileum exhibited no abnormalities in tissue appearance or electrical resistance. Expression of the IFNγ, IL1α, IL4, IL6, IL12p40, IL18, TGFβ1, and TNFα cytokine genes did not differ significantly among the intact ileum, catheterized loops, and interspaces, nor did the expression of the gene for inducible nitric oxide synthase. Broad-spectrum antibiotics administered during surgery did not sterilize the loops or interspaces and did not substantively change the composition of the microbiota. However, antibiotics reduced the overall number of bacterial cells within the loop and the relative abundance of community constituents. We concluded that catheterization of intestinal loops did not adversely affect health or loop function in sheep. Furthermore, allowing animals to recover fully from surgery and to clear pharmaceuticals will remove any confounding effects due to these factors, making catheterized intestinal loops a feasible model for studying host responses in ruminants. PMID:21262134

  18. Multi-instrument observations of coronal loops

    NASA Astrophysics Data System (ADS)

    Scott, Jason Terrence

    This document exhibits results of analysis from data collected with multiple EUV satellites (SOHO, TRACE, STEREO, Hinode, and SDO). The focus is the detailed observation of coronal loops using multiple instruments, i.e. filter imagers and spectrometers. Techniques for comparing the different instruments and deriving loop parameters are demonstrated. Attention is given to the effects the different instruments may introduce into the data and their interpretation. The assembled loop parameters are compared to basic energy balance equations and scaling laws. Discussion of the blue-shifted, asymmetric, and line broadened spectral line profiles near the footpoints of coronal loops is made. The first quantitative analysis of the anti-correlation between intensity and spectral line broadening for isolated regions along loops and their footpoints is presented. A magnetic model of an active region shows where the separatrices meet the photospheric boundary. At the boundary, the spectral data reveal concentrated regions of increased blue-shifted outflows, blue wing asymmetry, and line broadening. This is found just outside the footpoints of bright loops. The intensity and line broadening in this region are anti-correlated. A comparison of the similarities in the spectroscopic structure near the footpoints of the arcade loops and more isolated loops suggests the notion of consistent structuring for the bright loops forming an apparent edge of an active region core.

  19. Conservation law for linked cosmic string loops

    NASA Astrophysics Data System (ADS)

    Bekenstein, Jacob D.

    1992-05-01

    Taking a cue from the connection between fluid helicity and the linkage between closed vortices in ordinary turbulent flow, we examine topological restrictions on the linkage of cosmic string loops (or superfluid quantum vortex rings). The analog of helicity in these cases vanishes, but loops (and vortex rings) can link together, the extent of linkage (knotting included) being related to the contorsion of the loops or rings by a topological conservation law. This law is respected by intercommunication. One consequence is that total loop contorsion is quantized in integers.

  20. Unified framework for systematic loop transformations

    SciTech Connect

    Lu, L.C.; Chen, M.

    1990-10-01

    This paper presents a formal mathematical framework which unifies the existing loop transformations. This framework also includes more general classes of loop transformations, which can extract more parallelism from a class of programs than the existing techniques. We classify schedules into three classes: uniform, subdomain-variant, and statement-variant. Viewing from the degree of parallelism to be gained by loop transformation, the schedules can also be classified as single-sequential level, multiple-sequential level, and mixed schedules. We also illustrate the usefulness of the more general loop transformation with an example program.

  1. The complete mitochondrial genome of the Rana huanrensis (Anura: Ranidae).

    PubMed

    Dong, Bingjun; Zhou, Yu; Yang, Baotian

    2016-11-01

    We first determined complete mitochondrial genomes of R. huanrensis (Anura: Ranidae). The complete mtDNA sequence is 19 253 bp in length, including 13 protein-coding genes, 2 rRNA genes, 22 tRNA genes, and one displacement loop. The start/stop codons of protein-coding genes are similar to which of R. chensinensis. D-loop region of R. huanrensis is 3448 bp in size, contains many tandem repeat units. The phylogenetic trees of 18 species from Ranidae were reconstructed by BI and ML analyses. The result indicated that R. huanrensis is the most closely related species with other Rana species. The molecular data are expected to provide a useful tool for population genetics studies of this species and further phylogenetic analyses of Ranidae.

  2. Coherent semiclassical states for loop quantum cosmology

    NASA Astrophysics Data System (ADS)

    Corichi, Alejandro; Montoya, Edison

    2011-08-01

    The spatially flat Friedmann-Robertson-Walker cosmological model with a massless scalar field in loop quantum cosmology admits a description in terms of a completely solvable model. This has been used to prove that: (i) the quantum bounce that replaces the big bang singularity is generic; (ii) there is an upper bound on the energy density for all states, and (iii) semiclassical states at late times had to be semiclassical before the bounce. Here we consider a family of exact solutions to the theory, corresponding to generalized coherent Gaussian and squeezed states. We analyze the behavior of basic physical observables and impose restrictions on the states based on physical considerations. These turn out to be enough to select, from all the generalized coherent states, those that behave semiclassical at late times. We study then the properties of such states near the bounce where the most “quantum behavior” is expected. As it turns out, the states remain sharply peaked and semiclassical at the bounce and the dynamics is very well approximated by the “effective theory” throughout the time evolution. We compare the semiclassicality properties of squeezed states to those of the Gaussian semiclassical states and conclude that the Gaussians are better behaved. In particular, the asymmetry in the relative fluctuations before and after the bounce are negligible, thus ruling out claims of so-called “cosmic forgetfulness.”

  3. Invariant Connections in Loop Quantum Gravity

    NASA Astrophysics Data System (ADS)

    Hanusch, Maximilian

    2016-04-01

    Given a group {G}, and an abelian {C^*}-algebra {A}, the antihomomorphisms {Θ\\colon G→ {Aut}(A)} are in one-to-one with those left actions {Φ\\colon G× {Spec}(A)→ {Spec}(A)} whose translation maps {Φ_g} are continuous; whereby continuities of {Θ} and {Φ} turn out to be equivalent if {A} is unital. In particular, a left action {φ\\colon G × X→ X} can be uniquely extended to the spectrum of a {C^*}-subalgebra {A} of the bounded functions on {X} if {φ_g^*(A)subseteq A} holds for each {gin G}. In the present paper, we apply this to the framework of loop quantum gravity. We show that, on the level of the configuration spaces, quantization and reduction in general do not commute, i.e., that the symmetry-reduced quantum configuration space is (strictly) larger than the quantized configuration space of the reduced classical theory. Here, the quantum-reduced space has the advantage to be completely characterized by a simple algebraic relation, whereby the quantized reduced classical space is usually hard to compute.

  4. Highly conserved d-loop sequences in woolly mouse opossums Marmosa (Micoureus).

    PubMed

    Rocha, Rita Gomes; Leite, Yuri Luiz Reis; Ferreira, Eduardo; Justino, Juliana; Costa, Leonora Pires

    2012-04-01

    This study reports the occurrence of highly conserved d-loop sequences in the mitochondrial genome of the woolly mouse opossum genus Marmosa subgenus Micoureus (Mammalia, Didelphimorphia, Didelphidae). Sixty-six sequences of Marmosa (Micoureus) demerarae, Marmosa (Micoureus) constantiae, and Marmosa (Micoureus) paraguayanus were amplified using universal d-loop primers and virtually no genetic differences were detected within and among species. These sequences matched the control region of the mitochondrial marsupial genome. Analyses of qualitative aspects of these sequences revealed that their structural composition is very similar to the d-loop region of other didelphid species. However, the total lack of variability has not been reported from other closely related species. The data analyzed here support the occurrence of highly conserved d-loop sequences, and we found no support for the hypothesis that these sequences are d-loop-like nuclear pseudogenes. Furthermore, the control and flanking regions obtained with different primers corroborate the lack of variability of the d-loop sequences in the mitochondrial genome of Marmosa (Micoureus).

  5. Priming in word stem completion tasks: comparison with previous results in word fragment completion tasks

    PubMed Central

    Soler, María J.; Dasí, Carmen; Ruiz, Juan C.

    2015-01-01

    This study investigates priming in an implicit word stem completion (WSC) task by analyzing the effect of linguistic stimuli characteristics on said task. A total of 305 participants performed a WSC task in two phases (study and test). The test phase included 63 unique-solution stems and 63 multiple-solution stems. Analysis revealed that priming (mean = 0.22) was stronger in the case of multiple-solution stems, indicating that they were not a homogeneous group of stimuli. Thus, further analyses were performed only for the data of the unique-solution stems. Correlations between priming and familiarity, frequency of use, and baseline completion were significant. The less familiar words, which were less frequent, had higher priming values. At the same time, the stems with lower baseline completion generated more priming. A regression analysis showed that baseline completion was the only significant predictor of priming, suggesting that the previous processing of the stimuli had a greater impact on the stimuli with low baseline performance. At the same time, baseline completion showed significant positive correlations with familiarity and frequency of use, and a negative correlation with length. When baseline completion was the dependent variable in the regression analysis, the significant variables in the regression were familiarity and length. These results were compared with those obtained in a study using word fragment completion (WFC) by Soler et al. (2009), in which the same words and procedure were employed. Analysis showed that the variables that correlated with priming were the same as in the WSC task, and that completion baseline was the variable that showed the greatest predictive power of priming. This coincidence of results obtained with WFC and WSC tasks highlights the importance of controlling the characteristics of the stimuli used when exploring the nature of priming. PMID:26321987

  6. Priming in word stem completion tasks: comparison with previous results in word fragment completion tasks.

    PubMed

    Soler, María J; Dasí, Carmen; Ruiz, Juan C

    2015-01-01

    This study investigates priming in an implicit word stem completion (WSC) task by analyzing the effect of linguistic stimuli characteristics on said task. A total of 305 participants performed a WSC task in two phases (study and test). The test phase included 63 unique-solution stems and 63 multiple-solution stems. Analysis revealed that priming (mean = 0.22) was stronger in the case of multiple-solution stems, indicating that they were not a homogeneous group of stimuli. Thus, further analyses were performed only for the data of the unique-solution stems. Correlations between priming and familiarity, frequency of use, and baseline completion were significant. The less familiar words, which were less frequent, had higher priming values. At the same time, the stems with lower baseline completion generated more priming. A regression analysis showed that baseline completion was the only significant predictor of priming, suggesting that the previous processing of the stimuli had a greater impact on the stimuli with low baseline performance. At the same time, baseline completion showed significant positive correlations with familiarity and frequency of use, and a negative correlation with length. When baseline completion was the dependent variable in the regression analysis, the significant variables in the regression were familiarity and length. These results were compared with those obtained in a study using word fragment completion (WFC) by Soler et al. (2009), in which the same words and procedure were employed. Analysis showed that the variables that correlated with priming were the same as in the WSC task, and that completion baseline was the variable that showed the greatest predictive power of priming. This coincidence of results obtained with WFC and WSC tasks highlights the importance of controlling the characteristics of the stimuli used when exploring the nature of priming.

  7. Closed-Loop Neuroscience and Non-Invasive Brain Stimulation: A Tale of Two Loops

    PubMed Central

    Zrenner, Christoph; Belardinelli, Paolo; Müller-Dahlhaus, Florian; Ziemann, Ulf

    2016-01-01

    Closed-loop neuroscience is receiving increasing attention with recent technological advances that enable complex feedback loops to be implemented with millisecond resolution on commodity hardware. We summarize emerging conceptual and methodological frameworks that are available to experimenters investigating a “brain in the loop” using non-invasive brain stimulation and briefly review the experimental and therapeutic implications. We take the view that closed-loop neuroscience in fact deals with two conceptually quite different loops: a “brain-state dynamics” loop, used to couple with and modulate the trajectory of neuronal activity patterns, and a “task dynamics” loop, that is the bidirectional motor-sensory interaction between brain and (simulated) environment, and which enables goal-directed behavioral tasks to be incorporated. Both loops need to be considered and combined to realize the full experimental and therapeutic potential of closed-loop neuroscience. PMID:27092055

  8. Complete low power controller for high voltage power systems

    SciTech Connect

    Sumner, R.; Blanar, G.

    1997-12-31

    The MHV100 is a custom CMOS integrated circuit, developed for the AMS experiment. It provides complete control for a single channel high voltage (HV) generator and integrates all the required digital communications, D to A and A to D converters, the analog feedback loop and output drivers. This chip has been designed for use in both distributed high voltage systems or for low cost single channel high voltage systems. The output voltage and current range is determined by the external components.

  9. Delay locked loop integrated circuit.

    SciTech Connect

    Brocato, Robert Wesley

    2007-10-01

    This report gives a description of the development of a Delay Locked Loop (DLL) integrated circuit (IC). The DLL was developed and tested as a stand-alone IC test chip to be integrated into a larger application specific integrated circuit (ASIC), the Quadrature Digital Waveform Synthesizer (QDWS). The purpose of the DLL is to provide a digitally programmable delay to enable synchronization between an internal system clock and external peripherals with unknown clock skew. The DLL was designed and fabricated in the IBM 8RF process, a 0.13 {micro}m CMOS process. It was designed to operate with a 300MHz clock and has been tested up to 500MHz.

  10. DNA looping mediates nucleosome transfer

    PubMed Central

    Brennan, Lucy D.; Forties, Robert A.; Patel, Smita S.; Wang, Michelle D.

    2016-01-01

    Proper cell function requires preservation of the spatial organization of chromatin modifications. Maintenance of this epigenetic landscape necessitates the transfer of parental nucleosomes to newly replicated DNA, a process that is stringently regulated and intrinsically linked to replication fork dynamics. This creates a formidable setting from which to isolate the central mechanism of transfer. Here we utilized a minimal experimental system to track the fate of a single nucleosome following its displacement, and examined whether DNA mechanics itself, in the absence of any chaperones or assembly factors, may serve as a platform for the transfer process. We found that the nucleosome is passively transferred to available dsDNA as predicted by a simple physical model of DNA loop formation. These results demonstrate a fundamental role for DNA mechanics in mediating nucleosome transfer and preserving epigenetic integrity during replication. PMID:27808093

  11. Closed loop steam cooled airfoil

    DOEpatents

    Widrig, Scott M.; Rudolph, Ronald J.; Wagner, Gregg P.

    2006-04-18

    An airfoil, a method of manufacturing an airfoil, and a system for cooling an airfoil is provided. The cooling system can be used with an airfoil located in the first stages of a combustion turbine within a combined cycle power generation plant and involves flowing closed loop steam through a pin array set within an airfoil. The airfoil can comprise a cavity having a cooling chamber bounded by an interior wall and an exterior wall so that steam can enter the cavity, pass through the pin array, and then return to the cavity to thereby cool the airfoil. The method of manufacturing an airfoil can include a type of lost wax investment casting process in which a pin array is cast into an airfoil to form a cooling chamber.

  12. UWB communication receiver feedback loop

    DOEpatents

    Spiridon, Alex; Benzel, Dave; Dowla, Farid U.; Nekoogar, Faranak; Rosenbury, Erwin T.

    2007-12-04

    A novel technique and structure that maximizes the extraction of information from reference pulses for UWB-TR receivers is introduced. The scheme efficiently processes an incoming signal to suppress different types of UWB as well as non-UWB interference prior to signal detection. Such a method and system adds a feedback loop mechanism to enhance the signal-to-noise ratio of reference pulses in a conventional TR receiver. Moreover, sampling the second order statistical function such as, for example, the autocorrelation function (ACF) of the received signal and matching it to the ACF samples of the original pulses for each transmitted bit provides a more robust UWB communications method and system in the presence of channel distortions.

  13. R-loopDB: a database for R-loop forming sequences (RLFS) and R-loops

    PubMed Central

    Jenjaroenpun, Piroon; Wongsurawat, Thidathip; Sutheeworapong, Sawannee; Kuznetsov, Vladimir A.

    2017-01-01

    R-loopDB (http://rloop.bii.a-star.edu.sg) was originally constructed as a collection of computationally predicted R-loop forming sequences (RLFSs) in the human genic regions. The renewed R-loopDB provides updates, improvements and new options, including access to recent experimental data. It includes genome-scale prediction of RLFSs for humans, six other animals and yeast. Using the extended quantitative model of RLFSs (QmRLFS), we significantly increased the number of RLFSs predicted in the human genes and identified RLFSs in other organism genomes. R-loopDB allows searching of RLFSs in the genes and in the 2 kb upstream and downstream flanking sequences of any gene. R-loopDB exploits the Ensembl gene annotation system, providing users with chromosome coordinates, sequences, gene and genomic data of the 1 565 795 RLFSs distributed in 121 056 genic or proximal gene regions of the covered organisms. It provides a comprehensive annotation of Ensembl RLFS-positive genes including 93 454 protein coding genes, 12 480 long non-coding RNA and 7 568 small non-coding RNA genes and 7 554 pseudogenes. Using new interface and genome viewers of R-loopDB, users can search the gene(s) in multiple species with keywords in a single query. R-loopDB provides tools to carry out comparative evolution and genome-scale analyses in R-loop biology. PMID:27899586

  14. Three-loop cusp anomalous dimension and a conjecture for n loops

    NASA Astrophysics Data System (ADS)

    Kidonakis, Nikolaos

    2016-05-01

    I present analytical expressions for the massive cusp anomalous dimension in QCD through three loops, first calculated in 2014, in terms of elementary functions and ordinary polylogarithms. I observe interesting relations between the results at different loops and provide a conjecture for the n-loop cusp anomalous dimension in terms of the lower-loop results. I also present numerical results and simple approximate formulas for the cusp anomalous dimension relevant to top-quark production.

  15. Phenylnaphthalene Derivatives as Heat Transfer Fluids for Concentrating Solar Power: Loop Experiments and Final Report

    SciTech Connect

    McFarlane, Joanna; Bell, Jason R; Felde, David K; Joseph III, Robert Anthony; Qualls, A L; Weaver, Samuel P

    2013-02-01

    ORNL and subcontractor Cool Energy completed an investigation of higher-temperature, organic thermal fluids for solar thermal applications. Although static thermal tests showed promising results for 1-phenylnaphthalene, loop testing at temperatures to 450 C showed that the material isomerized at a slow rate. In a loop with a temperature high enough to drive the isomerization, the higher melting point byproducts tended to condense onto cooler surfaces. So, as experienced in loop operation, eventually the internal channels of cooler components such as the waste heat rejection exchanger may become coated or clogged and loop performance will decrease. Thus, pure 1-phenylnaphthalene does not appear to be a fluid that would have a sufficiently long lifetime (years to decades) to be used in a loop at the increased temperatures of interest. Hence a decision was made not to test the ORNL fluid in the loop at Cool Energy Inc. Instead, Cool Energy tested and modeled power conversion from a moderate-temperature solar loop using coupled Stirling engines. Cool Energy analyzed data collected on third and fourth generation SolarHeart Stirling engines operating on a rooftop solar field with a lower temperature (Marlotherm) heat transfer fluid. The operating efficiencies of the Stirling engines were determined at multiple, typical solar conditions, based on data from actual cycle operation. Results highlighted the advantages of inherent thermal energy storage in the power conversion system.

  16. Approximate inference on planar graphs using loop calculus and belief progagation

    SciTech Connect

    Chertkov, Michael; Gomez, Vicenc; Kappen, Hilbert

    2009-01-01

    We introduce novel results for approximate inference on planar graphical models using the loop calculus framework. The loop calculus (Chertkov and Chernyak, 2006b) allows to express the exact partition function Z of a graphical model as a finite sum of terms that can be evaluated once the belief propagation (BP) solution is known. In general, full summation over all correction terms is intractable. We develop an algorithm for the approach presented in Chertkov et al. (2008) which represents an efficient truncation scheme on planar graphs and a new representation of the series in terms of Pfaffians of matrices. We analyze in detail both the loop series and the Pfaffian series for models with binary variables and pairwise interactions, and show that the first term of the Pfaffian series can provide very accurate approximations. The algorithm outperforms previous truncation schemes of the loop series and is competitive with other state-of-the-art methods for approximate inference.

  17. Non-Gaussian features from the inverse volume corrections in loop quantum cosmology

    NASA Astrophysics Data System (ADS)

    Li, Li-Fang; Cai, Rong-Gen; Guo, Zong-Kuan; Hu, Bin

    2012-08-01

    In this paper we study the non-Gaussian features of the primordial fluctuations in loop quantum cosmology with the inverse volume corrections. The detailed analysis is performed in the single field slow-roll inflationary models. However, our results reflect the universal characteristics of bispectrum in loop quantum cosmology. The main corrections to the scalar bispectrum come from two aspects: one is the modifications to the standard Bunch-Davies vacuum, and the other is the corrections to the background dependent variables, such as slow-roll parameters. Our calculations show that the loop quantum corrections make fNL of the inflationary models increase 0.1%. Moreover, we find that two new shapes of non-Gaussian signal arise, which we name F1 and F2. The former gives a unique loop quantum feature, which is less correlated with the local, equilateral, and single types, while the latter is highly correlated with the local one.

  18. Gravitational steady states of solar coronal loops

    NASA Astrophysics Data System (ADS)

    Sugiyama, Linda E.; Asgari-Targhi, M.

    2017-02-01

    Coronal loops on the surface of the sun appear to consist of curved, plasma-confining magnetic flux tubes or "ropes," anchored at both ends in the photosphere. Toroidal loops carrying current are inherently unstable to expansion in the major radius due to toroidal-curvature-induced imbalances in the magnetic and plasma pressures. An ideal MHD analysis of a simple isolated loop with density and pressure higher than the surrounding corona, based on the theory of magnetically confined toroidal plasmas, shows that the radial force balance depends on the loop internal structure and varies over parameter space. It provides a unified picture of simple loop steady states in terms of the plasma beta βo, the inverse aspect ratio ɛ =a /Ro , and the MHD gravitational parameter G ̂≡g a /vA2 , all at the top of the loop, where g is the acceleration due to gravity, a the average minor radius, and vA the shear Alfvén velocity. In the high and low beta tokamak orderings, βo=2 noT /(Bo2/2 μo)˜ɛ1 and ɛ2 , that fit many loops, the solar gravity can sustain nonaxisymmetric steady states at G ̂˜ɛ βo that represent the maximum stable height. At smaller G ̂≤ɛ2βo , the loop is axisymmetric to leading order and stabilized primarily by the two fixed loop ends. Very low beta, nearly force-free, steady states with βo˜ɛ3 may also exist, with or without gravity, depending on higher order effects. The thin coronal loops commonly observed in solar active regions have ɛ ≃0.02 and fit the high beta steady states. G ̂ increases with loop height. Fatter loops in active regions that form along magnetic neutral lines and may lead to solar flares and Coronal Mass Ejections have ɛ ≃0.1 -0.2 and may fit the low beta ordering. Larger loops tend to have G ̂>ɛ βo and be unstable to radial expansion because the exponential hydrostatic reduction in the density at the loop-top reduces the gravitational force -ρG ̂ R ̂ below the level that balances expansion, in agreement with

  19. Dihedral-like constructions of automorphic loops

    NASA Astrophysics Data System (ADS)

    Aboras, Mouna

    In this dissertation we study dihedral-like constructions of automorphic loops. Automorphic loops are loops in which all inner mappings are automorphisms. We start by describing a generalization of the dihedral construction for groups. Namely, if (G, +) is an abelian group, m > 1 and alpha ∈2 Aut(G), let Dih(m, G, alpha) on Zm x G be defined by. (i, u)(j, v) = (i + j, ((--1)ju + v)alpha ij). We prove that the resulting loop is automorphic if and only if m = 2 or (alpha2 = 1 and m is even) or (m is odd, alpha = 1 and exp(G) ≤ 2). In the last case, the loop is a group. The case m = 2 was introduced by Kinyon, Kunen, Phillips, and Vojtechovsky. We study basic structural properties of dihedral-like automorphic loops. We describe certain subloops, including: nucleus, commutant, center, associator subloop and derived subloop. We prove theorems for dihedral-like automorphic loops analogous to the Cauchy and Lagrange theorems for groups, and further we discuss the coset decomposition in dihedral-like automorphic loops. We show that two finite dihedral-like automorphic loops Dih( m, G, alpha) and Dih(m¯, G¯, [special character omitted]) are isomorphic if and only if m = m¯, G ≅ G¯ and alpha is conjugate to [special character omitted] in Aut(G). We describe the automorphism group of Q and its subgroup consisting of inner mappings of Q. Finally, due to the solution to the isomorphism problem, we are interested in studying conjugacy classes of automorphism groups of finite abelian groups. Then we describe all dihedral-like automorphic loops of order < 128 up to isomorphism. We conclude with a description of all dihedral-like automorphic loops of order < 64 up to isotopism.

  20. Glycoprotein Degradation in the Blind Loop Syndrome

    PubMed Central

    Prizont, Roberto

    1981-01-01

    Contents obtained from jejunum of normal controls, self-emptying and self-filling blind loop rats were analyzed for the presence of glycoprotein-degrading glycosidases. The blind loop syndrome was documented by the increased fat excretion and slower growth rate of self-filling blind loop rats 6 wk after surgery. With p-nitrophenylglycosides as substrate, the specific activity of α-N-acetylgalactosaminidase, a potential blood group A destroying glycosidase, was 0.90±0.40 mU/mg of protein. This level was 23-fold higher than the specific activity of normal controls. In partially purified self-filling blind loop contents, the activity of α-N-acetylgalactosaminidase was 9- to 70-fold higher than activities of self-emptying and normal controls. Antibiotic treatment with chloromycetin and polymyxin decreased 24-fold the glycosidase levels in self-filling blind loops. In experiments with natural substrate, the blood group A titer of a20,000g supernate from normal jejunal homogenates decreased 128-fold after 24-h incubation with blind loop contents. Normal contents failed to diminish the blood group reactivity of the natural substrate. Furthermore, blind loop contents markedly decreased the blood group A titer of isolated brush borders. Incubation between blind loop bacteria and mucosal homogenates or isolated brush borders labeled with d-[U-14C]glucosamine revealed increased production of labeled ether extractable organic acids. Likewise, intraperitoneal injection of d-[U-14C]glucosamine into self-filling blind loop rats resulted in incorporation of the label into luminal short chain fatty acids. These results suggest that glycosidases may provide a mechanism by which blind loop bacteria obtain sugars from intestinal glycoproteins. The released sugars are used and converted by bacteria into energy and organic acids. This use of the host's glycoproteins would allow blind loop bacteria to grow and survive within the lumen independent of exogenous sources. PMID:6257760

  1. Completing the Feedback Loop: The Impact of Chlorophyll Data Assimilation on the Ocean State

    NASA Technical Reports Server (NTRS)

    Borovikov, Anna; Keppenne, Christian; Kovach, Robin

    2015-01-01

    In anticipation of the integration of a full biochemical model into the next generation GMAO coupled system, an intermediate solution has been implemented to estimate the penetration depth (1Kd_PAR) of ocean radiation based on the chlorophyll concentration. The chlorophyll is modeled as a tracer with sources-sinks coming from the assimilation of MODIS chlorophyll data. Two experiments were conducted with the coupled ocean-atmosphere model. In the first, climatological values of Kpar were used. In the second, retrieved daily chlorophyll concentrations were assimilated and Kd_PAR was derived according to Morel et al (2007). No other data was assimilated to isolate the effects of the time-evolving chlorophyll field. The daily MODIS Kd_PAR product was used to validate the skill of the penetration depth estimation and the MERRA-OCEAN re-analysis was used as a benchmark to study the sensitivity of the upper ocean heat content and vertical temperature distribution to the chlorophyll input. In the experiment with daily chlorophyll data assimilation, the penetration depth was estimated more accurately, especially in the tropics. As a result, the temperature bias of the model was reduced. A notably robust albeit small (2-5 percent) improvement was found across the equatorial Pacific ocean, which is a critical region for seasonal to inter-annual prediction.

  2. The Polyakov loop correlator at NNLO and singlet and octet correlators

    SciTech Connect

    Ghiglieri, Jacopo

    2011-05-23

    We present the complete next-to-next-to-leading-order calculation of the correlation function of two Polyakov loops for temperatures smaller than the inverse distance between the loops and larger than the Coulomb potential. We discuss the relationship of this correlator with the singlet and octet potentials which we obtain in an Effective Field Theory framework based on finite-temperature potential Non-Relativistic QCD, showing that the Polyakov loop correlator can be re-expressed, at the leading order in a multipole expansion, as a sum of singlet and octet contributions. We also revisit the calculation of the expectation value of the Polyakov loop at next-to-next-to-leading order.

  3. Study of the fast photoswitching of spin crossover nanoparticles outside and inside their thermal hysteresis loop

    SciTech Connect

    Galle, G.; Degert, J.; Freysz, E.; Etrillard, C.; Letard, J.-F.; Guillaume, F.

    2013-02-11

    We have studied the low spin to high spin phase transition induced by nanosecond laser pulses outside and within the thermal hysteresis loop of the [Fe(Htrz){sub 2} trz](BF{sub 4}){sub 2}-H{sub 2}O spin crossover nanoparticles. We demonstrate that, whatever the temperature of the compound, the photo-switching is achieved in less than 12.5 ns. Outside the hysteresis loop, the photo-induced high spin state remains up to 100 {mu}s and then relaxes. Within the thermal hysteresis loop, the photo-induced high spin state remains as long as the temperature of the sample is kept within the thermal loop. A Raman study indicates that the photo-switching can be completed using single laser pulse excitation.

  4. Automatic calculation of supersymmetric renormalization group equations and loop corrections

    NASA Astrophysics Data System (ADS)

    Staub, Florian

    2011-03-01

    SARAH is a Mathematica package for studying supersymmetric models. It calculates for a given model the masses, tadpole equations and all vertices at tree-level. This information can be used by SARAH to write model files for CalcHep/ CompHep or FeynArts/ FormCalc. In addition, the second version of SARAH can derive the renormalization group equations for the gauge couplings, parameters of the superpotential and soft-breaking parameters at one- and two-loop level. Furthermore, it calculates the one-loop self-energies and the one-loop corrections to the tadpoles. SARAH can handle all N=1 SUSY models whose gauge sector is a direct product of SU(N) and U(1) gauge groups. The particle content of the model can be an arbitrary number of chiral superfields transforming as any irreducible representation with respect to the gauge groups. To implement a new model, the user has just to define the gauge sector, the particle, the superpotential and the field rotations to mass eigenstates. Program summaryProgram title: SARAH Catalogue identifier: AEIB_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEIB_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 97 577 No. of bytes in distributed program, including test data, etc.: 2 009 769 Distribution format: tar.gz Programming language: Mathematica Computer: All systems that Mathematica is available for Operating system: All systems that Mathematica is available for Classification: 11.1, 11.6 Nature of problem: A supersymmetric model is usually characterized by the particle content, the gauge sector and the superpotential. It is a time consuming process to obtain all necessary information for phenomenological studies from these basic ingredients. Solution method: SARAH calculates the complete Lagrangian for a given model whose

  5. The Cygnus Loop: An Older Supernova Remnant.

    ERIC Educational Resources Information Center

    Straka, William

    1987-01-01

    Describes the Cygnus Loop, one of brightest and most easily studied of the older "remnant nebulae" of supernova outbursts. Discusses some of the historical events surrounding the discovery and measurement of the Cygnus Loop and makes some projections on its future. (TW)

  6. Formation of Chromosomal Domains by Loop Extrusion.

    PubMed

    Fudenberg, Geoffrey; Imakaev, Maxim; Lu, Carolyn; Goloborodko, Anton; Abdennur, Nezar; Mirny, Leonid A

    2016-05-31

    Topologically associating domains (TADs) are fundamental structural and functional building blocks of human interphase chromosomes, yet the mechanisms of TAD formation remain unclear. Here, we propose that loop extrusion underlies TAD formation. In this process, cis-acting loop-extruding factors, likely cohesins, form progressively larger loops but stall at TAD boundaries due to interactions with boundary proteins, including CTCF. Using polymer simulations, we show that this model produces TADs and finer-scale features of Hi-C data. Each TAD emerges from multiple loops dynamically formed through extrusion, contrary to typical illustrations of single static loops. Loop extrusion both explains diverse experimental observations-including the preferential orientation of CTCF motifs, enrichments of architectural proteins at TAD boundaries, and boundary deletion experiments-and makes specific predictions for the depletion of CTCF versus cohesin. Finally, loop extrusion has potentially far-ranging consequences for processes such as enhancer-promoter interactions, orientation-specific chromosomal looping, and compaction of mitotic chromosomes.

  7. External Tank CIL Closed Loop Verification System

    NASA Technical Reports Server (NTRS)

    Hartley, Eugene A., Jr.

    2005-01-01

    Lockheed Martin was requested to develop a closed loop CIL system following the Challenger accident. The system that was developed has proven to be very robust with minimal problems since implementation, having zero escapes in the last 7 years (27 External Tanks). We are currently investigating expansion of the CIL Closed Loop system to include "MI" CILs.

  8. Loop calculus for lattice gauge theories

    SciTech Connect

    Gambini, R.; Leal, L.; Trias, A.

    1989-05-15

    Hamiltonian calculations are performed using a loop-labeled basis where the full set of identities for the SU(/ital N/) gauge models has been incorporated. The loops are classified as clusterlike structures and the eigenvalue problem leads to a linear set of finite-difference equations easily amenable to numerical treatment. Encouraging results are reported for SU(2) at spatial dimension 2.

  9. On Novice Loop Boundaries and Range Conceptions

    ERIC Educational Resources Information Center

    Ginat, David

    2004-01-01

    The paper presents a study of novice difficulties with range conceptions in loop design. CS2 students were asked to solve four related enumeration tasks, which required various loop boundary specifications. The student solutions varied considerably in conciseness and efficiency. The solution diversity reveals significant differences in range…

  10. Vacuum Energy Sequestering and Graviton Loops.

    PubMed

    Kaloper, Nemanja; Padilla, Antonio

    2017-02-10

    We recently formulated a local mechanism of vacuum energy sequester. This mechanism automatically removes all matter loop contributions to vacuum energy from the stress energy tensor which sources the curvature. Here we adapt the local vacuum energy sequestering mechanism to also cancel all the vacuum energy loops involving virtual gravitons, in addition to the vacuum energy generated by matter fields alone.

  11. Vacuum Energy Sequestering and Graviton Loops

    NASA Astrophysics Data System (ADS)

    Kaloper, Nemanja; Padilla, Antonio

    2017-02-01

    We recently formulated a local mechanism of vacuum energy sequester. This mechanism automatically removes all matter loop contributions to vacuum energy from the stress energy tensor which sources the curvature. Here we adapt the local vacuum energy sequestering mechanism to also cancel all the vacuum energy loops involving virtual gravitons, in addition to the vacuum energy generated by matter fields alone.

  12. Spring control of wire harness loops

    NASA Technical Reports Server (NTRS)

    Curcio, P. J.

    1979-01-01

    Negator spring control guides wire harness between movable and fixed structure. It prevents electrical wire harness loop from jamming or being severed as wire moves in response to changes in position of aircraft rudder. Spring-loaded coiled cable controls wire loop regardless of rudder movement.

  13. Acquisition performance of various QPSK carrier tracking loops

    NASA Technical Reports Server (NTRS)

    Hinedi, S.; Shah, B.

    1992-01-01

    The frequency and phase acquisition performance of three quadrature phase shift keying (QPSK) carrier tracking loops, the MAP estimation loop, the Costas crossover loop, and the generalized Costas loop, is described. Acquisition time and probability of acquisition as a function of both loop signal-to-noise ratio and frequency offset to loop bandwidth ratio are obtained via computer simulations for type II and III loops. It is shown that the MAP loop, which results in the smallest squaring loss for all signal-to-noise ratios, is sometimes outperformed by the other two loops in terms of acquisition time and acquisition probability.

  14. Contrasting HIV phylogenetic relationships and V3 loop protein similarities

    SciTech Connect

    Korber, B. Santa Fe Inst., NM ); Myers, G. )

    1992-01-01

    At least five distinct sequence subtypes of HIV-I can be identified from the major centers of the AMS pandemic. While it is too early to tell whether these subtypes are serologically or phenotypically similar or distinct in terms of properties such as pathogenicity and transmissibility, we can begin to investigate their potential for phenotypic divergence at the protein sequence level. Phylogenetic analysis of HIV DNA sequences is being widely used to examine lineages of different viral strains as they evolve and spread throughout the globe. We have identified five distinct HIV-1 subtypes (designated A-E), or clades, based on phylogenetic clustering patterns generated from genetic information from both the gag and envelope (env) genes from a spectrum of international isolates. Our initial observations concerning both HIV-1 and HIV-2 sequences indicate that conserved patterns in protein chemistry may indeed exist across distant lineages. Such patterns in V3 loop amino acid chemistry may be indicative of stable lineages or convergence within this highly variable, though functionally and immunologically critical, region. We think that there may be parallels between the apparently stable HIV-2 V3 lineage and the previously mentioned HIV-1 V3 loops which are very similar at the protein level despite being distant by cladistic analysis, and which do not possess the distinctive positively charged residues. Highly conserved V3 loop protein sequences are also encountered in SIVAGMs and CIVs (chimpanzee viral strains), which do not appear to be pathogenic in their wild-caught natural hosts.

  15. Contrasting HIV phylogenetic relationships and V3 loop protein similarities

    SciTech Connect

    Korber, B. |; Myers, G.

    1992-12-31

    At least five distinct sequence subtypes of HIV-I can be identified from the major centers of the AMS pandemic. While it is too early to tell whether these subtypes are serologically or phenotypically similar or distinct in terms of properties such as pathogenicity and transmissibility, we can begin to investigate their potential for phenotypic divergence at the protein sequence level. Phylogenetic analysis of HIV DNA sequences is being widely used to examine lineages of different viral strains as they evolve and spread throughout the globe. We have identified five distinct HIV-1 subtypes (designated A-E), or clades, based on phylogenetic clustering patterns generated from genetic information from both the gag and envelope (env) genes from a spectrum of international isolates. Our initial observations concerning both HIV-1 and HIV-2 sequences indicate that conserved patterns in protein chemistry may indeed exist across distant lineages. Such patterns in V3 loop amino acid chemistry may be indicative of stable lineages or convergence within this highly variable, though functionally and immunologically critical, region. We think that there may be parallels between the apparently stable HIV-2 V3 lineage and the previously mentioned HIV-1 V3 loops which are very similar at the protein level despite being distant by cladistic analysis, and which do not possess the distinctive positively charged residues. Highly conserved V3 loop protein sequences are also encountered in SIVAGMs and CIVs (chimpanzee viral strains), which do not appear to be pathogenic in their wild-caught natural hosts.

  16. REVIEWS OF TOPICAL PROBLEMS: Coronal magnetic loops

    NASA Astrophysics Data System (ADS)

    Zaitsev, Valerii V.; Stepanov, Alexander V.

    2008-11-01

    The goal of this review is to outline some new ideas in the physics of coronal magnetic loops, the fundamental structural elements of the atmospheres of the Sun and flaring stars, which are involved in phenomena such as stellar coronal heating, flare energy release, charged particle acceleration, and the modulation of optical, radio, and X-ray emissions. The Alfvén-Carlqvist view of a coronal loop as an equivalent electric circuit allows a good physical understanding of loop processes. Describing coronal loops as MHD-resonators explains various ways in which flaring emissions from the Sun and stars are modulated, whereas modeling them by magnetic mirror traps allows one to describe the dynamics and emission of high-energy particles. Based on these approaches, loop plasma and fast particle parameters are obtained and models for flare energy release and stellar corona heating are developed.

  17. Damped transverse oscillations of interacting coronal loops

    NASA Astrophysics Data System (ADS)

    Soler, Roberto; Luna, Manuel

    2015-10-01

    Damped transverse oscillations of magnetic loops are routinely observed in the solar corona. This phenomenon is interpreted as standing kink magnetohydrodynamic waves, which are damped by resonant absorption owing to plasma inhomogeneity across the magnetic field. The periods and damping times of these oscillations can be used to probe the physical conditions of the coronal medium. Some observations suggest that interaction between neighboring oscillating loops in an active region may be important and can modify the properties of the oscillations. Here we theoretically investigate resonantly damped transverse oscillations of interacting nonuniform coronal loops. We provide a semi-analytic method, based on the T-matrix theory of scattering, to compute the frequencies and damping rates of collective oscillations of an arbitrary configuration of parallel cylindrical loops. The effect of resonant damping is included in the T-matrix scheme in the thin boundary approximation. Analytic and numerical results in the specific case of two interacting loops are given as an application.

  18. Elliptic multiple zeta values and one-loop superstring amplitudes

    NASA Astrophysics Data System (ADS)

    Broedel, Johannes; Mafra, Carlos R.; Matthes, Nils; Schlotterer, Oliver

    2015-07-01

    We investigate iterated integrals on an elliptic curve, which are a natural genus-one generalization of multiple polylogarithms. These iterated integrals coincide with the multiple elliptic polylogarithms introduced by Brown and Levin when constrained to the real line. At unit argument they reduce to an elliptic analogue of multiple zeta values, whose network of relations we start to explore. A simple and natural application of this framework are one-loop scattering amplitudes in open superstring theory. In particular, elliptic multiple zeta values are a suitable language to express their low energy limit. Similar to the techniques available at tree-level, our formalism allows to completely automatize the calculation.

  19. A communication scheme for the distrubted execution of loop nests with while loops

    SciTech Connect

    Griebl, M.; Lengauer, C.

    1995-10-01

    The mathematical model for the parallelization, or {open_quotes}space-time mapping,{close_quotes} of loop nests is the polyhedron model. The presence of while loops in the nest complicates matters for two reasons: (1) the parallelized loop nest does not correspond to a polyhedron but instead to a subset that resembles a (multi-dimensional) comb and (2) it is not clear when the entire loop nest has terminated. We describe a communication scheme which can deal with both problems and which can be added to the parallel target loop nest by a compiler.

  20. An Experimental Study of the Operating Temperature in a Loop Heat Pipe with Two Evaporators and Two Condensers

    NASA Technical Reports Server (NTRS)

    Ku, Jentung; Birur, Gaj; Powers, Edward I. (Technical Monitor)

    2001-01-01

    This paper presents a comprehensive experimental study of the loop operating temperature in a loop heat pipe (LHP) which has two parallel evaporators and two parallel condensers. In a single evaporator LHP, it is well known that the loop operating temperature is a function of the heat load, the sink temperature and the ambient temperature. The objective of the present study emphasizes on the stability of the loop operating temperature and parameters that affects the loop operation. Tests results show that the loop operating temperature is a function of the total system heat load, sink temperature, ambient temperature, and beat load distribution between the two evaporators. Under most conditions, only one compensation chamber (CC) contains two-phase fluid and controls the loop operating temperature, and the other CC is completely filled with liquid. Moreover, as the test condition changes, control of the loop operating temperature often shifted from one CC to another. In spite of complex interactions between various components, the test loop has demonstrated very robust operation even during fast transients.

  1. Simulated Time Lags of Hinode/XRT and SDO/AIA Lightcurves as an Indication of Loop Heating Scenario

    NASA Technical Reports Server (NTRS)

    Alexander, C. E.; Lionello, R.; Winebarger, A. R.

    2014-01-01

    The precise nature of the heating mechanism (location, duration) in coronal loops is still a matter of enormous research. We present results from a one-dimensional (1D) hydrodynamic loop simulation of a coronal loop which was run using different parameters such as loops length (50, 200 and 500 light-seconds), maximum temperature reached (3 million degrees Kelvin and 10 million degrees Kelvin), and abundances. For each scenario the model outputs were used to calculate the corresponding lightcurves as seen by X-ray telescope/Be-thin filter and various Extreme Ultra Violet Atmospheric Imaging Assembly channels. The lag time between the peak of these lightcurves was computed using cross-correlation and plotted as a function of loop length. Additional results were computed using the zero-dimensional Enthalpy-Based Thermal Evolution of Loops (EBTEL) code in order to test the compatibility of the two codes and to investigate additional loop lengths. Initial results indicate that the long (greater than 5000 seconds) lags observed in the approximately 100 light-seconds loops of active regions can only be reproduced using photospheric abundances and much longer loop lengths. This result suggests that the observed time lags cannot be completely explained by impulsive heating.

  2. Ultra-high-frequency piecewise-linear chaos using delayed feedback loops

    NASA Astrophysics Data System (ADS)

    Cohen, Seth D.; Rontani, Damien; Gauthier, Daniel J.

    2012-12-01

    We report on an ultra-high-frequency (>1 GHz), piecewise-linear chaotic system designed from low-cost, commercially available electronic components. The system is composed of two electronic time-delayed feedback loops: A primary analog loop with a variable gain that produces multi-mode oscillations centered around 2 GHz and a secondary loop that switches the variable gain between two different values by means of a digital-like signal. We demonstrate experimentally and numerically that such an approach allows for the simultaneous generation of analog and digital chaos, where the digital chaos can be used to partition the system's attractor, forming the foundation for a symbolic dynamics with potential applications in noise-resilient communications and radar.

  3. High resolution interface circuit for closed-loop accelerometer

    NASA Astrophysics Data System (ADS)

    Liang, Yin; Xiaowei, Liu; Weiping, Chen; Zhiping, Zhou

    2011-04-01

    This paper reports a low noise switched-capacitor CMOS interface circuit for the closed-loop operation of a capacitive accelerometer. The time division multiplexing of the same electrode is adopted to avoid the strong feedthrough between capacitance sensing and electrostatic force feedback. A PID controller is designed to ensure the stability and dynamic response of a high Q closed-loop accelerometer with a vacuum package. The architecture only requires single ended operational amplifiers, transmission gates and capacitors. Test results show that a full scale acceleration of ±3 g, non-linearity of 0.05% and signal bandwidth of 1000 Hz are achieved. The complete module operates from a ±5 V supply and has a measured sensitivity of 1.2 V/g with a noise of floor of in closed-loop. The chip is fabricated in the 2 μm two-metal and two-poly n-well CMOS process with an area of 15.2 mm2. These results prove that this circuit is suitable for high performance micro-accelerometer applications like seismic detection and oil exploration.

  4. Spin-2 form factors at three loop in QCD

    NASA Astrophysics Data System (ADS)

    Ahmed, Taushif; Das, Goutam; Mathews, Prakash; Rana, Narayan; Ravindran, V.

    2015-12-01

    Spin-2 fields are often candidates in physics beyond the Standard Model namely the models with extra-dimensions where spin-2 Kaluza-Klein gravitons couple to the fields of the Standard Model. Also, in the context of Higgs searches, spin-2 fields have been studied as an alternative to the scalar Higgs boson. In this article, we present the complete three loop QCD radiative corrections to the spin-2 quark-antiquark and spin-2 gluon-gluon form factors in SU(N) gauge theory with n f light flavors. These form factors contribute to both quark-antiquark and gluon-gluon initiated processes involving spin-2 particle in the hadronic reactions at the LHC. We have studied the structure of infrared singularities in these form factors up to three loop level using Sudakov integro-differential equation and found that the anomalous dimensions originating from soft and collinear regions of the loop integrals coincide with those of the electroweak vector boson and Higgs form factors confirming the universality of the infrared singularities in QCD amplitudes.

  5. Experiment to Study Alfven Wave Propagation in Plasma Loops

    NASA Astrophysics Data System (ADS)

    Kendall, Mark; Bellan, Paul

    2010-11-01

    Arched plasma-filled twisted magnetic flux tubes are generated in the laboratory using pulsed power techniques (J.F. Hansen, S.K.P. Tripathi, P.M. Bellan, 2004). Their structure and time evolution exhibit similarities with both solar coronal loops and spheromaks. We are now developing a method to excite propagating torsional Alfven wave modes in such plasma loops by superposing a ˜10kA, ˜100ns current pulse upon the ˜50kA, 10μs main discharge current that flows along the ˜20cm long, 2cm diameter arched flux tube. To achieve this high power 100ns pulse, a magnetic pulse compression technique based on saturable reactors is employed. A low power prototype has been successfully tested, and design and construction of a full-power device is nearing completion. The full-power device will compress an initial 2μs pulse by a factor of nearly 20; the final stage utilizes a water-filled transmission line with ultra-low inductance to attain the final timescale. This new pulse device will subsequently be used to investigate interactions between Alfven waves and the larger-scale loop evolution; one goal will be to directly image the wave using high-speed photography. Attention will be paid to wave propagation including dispersion and reflection, as well as dissipation mechanisms and possible energetic particle generation.

  6. Investigation of Capillary Limit in a Loop Heat Pipe

    NASA Technical Reports Server (NTRS)

    Ku, Jentung; Ottenstein, Laura; Rogers, Paul; Cheung, Kwok; Obenschain, Arthur F. (Technical Monitor)

    2001-01-01

    This paper presets an experimental study on the capillary limit of a loop heat pipe (LHP) at low powers. The slow thermal response of the loop at low powers made it possible to observe interactions among various components after the capillary limit was exceeded. The capillary limit at low powers was achieved by imposing additional pressure drops on the vapor line through the use of a metering valve. A differential pressure transducer was also used to measure the pressure drop across the evaporator and the compensation chamber (CC). Test results show that when the capillary limit is exceeded, vapor will penetrate the primary wick, resulting in a partial dry-out of the evaporator and a rapid increase of the CC temperature. Because the evaporator can tolerate vapor bubbles, the LHP will continue to function and may reach a new steady state at the higher temperature. Thus, the LHP will exhibit a graceful degradation in performance rather than a complete failure. Moreover, the loop can recover from a partial dry-out by reducing the heat load without a re-start.

  7. Cygnus Loop Supernova Blast Wave

    NASA Technical Reports Server (NTRS)

    1993-01-01

    This is an image of a small portion of the Cygnus Loop supernova remnant, which marks the edge of a bubble-like, expanding blast wave from a colossal stellar explosion, occurring about 15,000 years ago. The HST image shows the structure behind the shock waves, allowing astronomers for the first time to directly compare the actual structure of the shock with theoretical model calculations. Besides supernova remnants, these shock models are important in understanding a wide range of astrophysical phenomena, from winds in newly-formed stars to cataclysmic stellar outbursts. The supernova blast is slamming into tenuous clouds of insterstellar gas. This collision heats and compresses the gas, causing it to glow. The shock thus acts as a searchlight revealing the structure of the interstellar medium. The detailed HST image shows the blast wave overrunning dense clumps of gas, which despite HST's high resolution, cannot be resolved. This means that the clumps of gas must be small enough to fit inside our solar system, making them relatively small structures by interstellar standards. A bluish ribbon of light stretching left to right across the picture might be a knot of gas ejected by the supernova; this interstellar 'bullet' traveling over three million miles per hour (5 million kilometres) is just catching up with the shock front, which has slowed down by ploughing into interstellar material. The Cygnus Loop appears as a faint ring of glowing gases about three degrees across (six times the diameter of the full Moon), located in the northern constellation, Cygnus the Swan. The supernova remnant is within the plane of our Milky Way galaxy and is 2,600 light-years away. The photo is a combination of separate images taken in three colors, oxygen atoms (blue) emit light at temperatures of 30,000 to 60,000 degrees Celsius (50,000 to 100,000 degrees Farenheit). Hydrogen atoms (green) arise throughout the region of shocked gas. Sulfur atoms (red) form when the gas cools to

  8. Quantitation of interactions between two DNA loops demonstrates loop domain insulation in E. coli cells

    PubMed Central

    Priest, David G.; Kumar, Sandip; Yan, Yan; Dunlap, David D.; Dodd, Ian B.; Shearwin, Keith E.

    2014-01-01

    Eukaryotic gene regulation involves complex patterns of long-range DNA-looping interactions between enhancers and promoters, but how these specific interactions are achieved is poorly understood. Models that posit other DNA loops—that aid or inhibit enhancer–promoter contact—are difficult to test or quantitate rigorously in eukaryotic cells. Here, we use the well-characterized DNA-looping proteins Lac repressor and phage λ CI to measure interactions between pairs of long DNA loops in E. coli cells in the three possible topological arrangements. We find that side-by-side loops do not affect each other. Nested loops assist each other’s formation consistent with their distance-shortening effect. In contrast, alternating loops, where one looping element is placed within the other DNA loop, inhibit each other’s formation, thus providing clear support for the loop domain model for insulation. Modeling shows that combining loop assistance and loop interference can provide strong specificity in long-range interactions. PMID:25288735

  9. Sequence–structure relationships in RNA loops: establishing the basis for loop homology modeling

    PubMed Central

    Schudoma, Christian; May, Patrick; Nikiforova, Viktoria; Walther, Dirk

    2010-01-01

    The specific function of RNA molecules frequently resides in their seemingly unstructured loop regions. We performed a systematic analysis of RNA loops extracted from experimentally determined three-dimensional structures of RNA molecules. A comprehensive loop-structure data set was created and organized into distinct clusters based on structural and sequence similarity. We detected clear evidence of the hallmark of homology present in the sequence–structure relationships in loops. Loops differing by <25% in sequence identity fold into very similar structures. Thus, our results support the application of homology modeling for RNA loop model building. We established a threshold that may guide the sequence divergence-based selection of template structures for RNA loop homology modeling. Of all possible sequences that are, under the assumption of isosteric relationships, theoretically compatible with actual sequences observed in RNA structures, only a small fraction is contained in the Rfam database of RNA sequences and classes implying that the actual RNA loop space may consist of a limited number of unique loop structures and conserved sequences. The loop-structure data sets are made available via an online database, RLooM. RLooM also offers functionalities for the modeling of RNA loop structures in support of RNA engineering and design efforts. PMID:19923230

  10. Looping charged elastic rods: applications to protein-induced DNA loop formation.

    PubMed

    Cherstvy, A G

    2011-01-01

    We analyze looping of thin charged elastic filaments under applied torques and end forces, using the solution of linear elasticity theory equations. In application to DNA, we account for its polyelectrolyte character and charge renormalization, calculating electrostatic energies stored in the loops. We argue that the standard theory of electrostatic persistence is only valid when the loop's radius of curvature and close-contact distance are much larger than the Debye screening length. We predict that larger twist rates are required to trigger looping of charged rods as compared with neutral ones. We then analyze loop shapes formed on charged filaments of finite length, mimicking DNA looping by proteins with two DNA-binding domains. We find optimal loop shapes at different salt amounts, minimizing the sum of DNA elastic, DNA electrostatic, and protein elastic energies. We implement a simple model where intercharge repulsions do not affect the loop shape directly but can choose the energy-optimized shape from the allowed loop types. At low salt concentrations more open loops are favored due to enhanced repulsion of DNA charges, consistent with the results of computer simulations on formation of DNA loops by lac repressor. Then, we model the precise geometry of DNA binding by the lac tetramer and explore loop shapes, varying the confined DNA length and protein opening angle. The characteristics of complexes obtained, such as the total loop energy, stretching forces required to maintain its shape, and the reduction of electrostatic energy with increment of salt, are in good agreement with the outcomes of more elaborate numerical calculations for lac-repressor-induced DNA looping.

  11. Simulation methods for looping transitions.

    PubMed

    Gaffney, B J; Silverstone, H J

    1998-09-01

    Looping transitions occur in field-swept electron magnetic resonance spectra near avoided crossings and involve a single pair of energy levels that are in resonance at two magnetic field strengths, before and after the avoided crossing. When the distance between the two resonances approaches a linewidth, the usual simulation of the spectra, which results from a linear approximation of the dependence of the transition frequency on magnetic field, breaks down. A cubic approximation to the transition frequency, which can be obtained from the two resonance fields and the field-derivatives of the transition frequencies, along with linear (or better) interpolation of the transition-probability factor, restores accurate simulation. The difference is crucial for accurate line shapes at fixed angles, as in an oriented single crystal, but the difference turns out to be a smaller change in relative intensity for a powder spectrum. Spin-3/2 Cr3+ in ruby and spin-5/2 Fe3+ in transferrin oxalate are treated as examples.

  12. BOOK REVIEW: Complete Physics

    NASA Astrophysics Data System (ADS)

    Carson, Simon

    2000-03-01

    ', begins with an emphasis on the correct use of units in calculations that is very good (although again only really appropriate for more able students) and considers scientific notation and SI units. The use of triangles for rearranging three variable equations is introduced without any discussion of how to do the algebra properly. I found this rather out of place in a book of this level; I should personally hope to see those intending to pursue the subject beyond GCSE capable of rearranging equations without recourse to methods which convey no understanding of the physical relationship. The section on the `History of Key Ideas' has a double page spread on `Forces, Motion and Energy', `Rays, Waves and Particles' and `The Earth and Beyond', followed by a chronology of physics from 400 BC to 1990. These sections are necessarily very brief. The final section, `Experimental Physics', has some useful reminders for students about investigative work and a photocopiable checklist. The book has some very attractive features. Most pages include a boxed list of `essentials' that are useful either in skimming the text to find useful information or in revision. Each double page spread into which the material is arranged includes some fairly straightforward questions to test the basic ideas. Each section ends with a set of examination questions and with a checklist of ideas that can be photocopied for students to tick off what has been covered. The contents pages of the book may also be photocopied for students to check their progress. Given that this is a brand new book, I found the inclusion of a spread on ticker-tape rather old-fashioned: video is a much better way of analysing motion. The language of the text, too, can be rather dry and academic, and the organization reflects a traditional approach to the physics curriculum. The book would be most useful, I think, to able students studying single-subject physics courses at GCSE or to those beginning A-level. At £14.00 a copy, it

  13. Point particles in 2+1 dimensions: general relativity and loop gravity descriptions

    NASA Astrophysics Data System (ADS)

    Ziprick, Jonathan

    2015-02-01

    We develop a Hamiltonian description of point particles in (2+1)-dimensions using connection and frame-field variables for general relativity. The topology of each spatial hypersurface is that of a punctured two-sphere with particles residing at the punctures. We describe this topology with a CW complex (a collection of two cells glued together along the edges), and use this to fix a gauge and reduce the Hamiltonian. The equations of motion for the fields describe a dynamical triangulation where each vertex moves according to the equation of motion for a free relativistic particle. The evolution is continuous except for when triangles collapse (i.e. the edges become parallel) causing discrete, topological changes in the underlying CW complex. We then introduce the loop gravity phase space parameterized by holonomy-flux variables on a graph (a network of one-dimensional links). By embedding a graph within the CW complex, we find a description of this system in terms of loop variables. The resulting equations of motion describe the same dynamical triangulation as the connection and frame-field variables. In this framework, the collapse of a triangle causes a discrete change in the underlying graph, giving a concrete realization of the graph-changing moves that many expect to feature in full loop quantum gravity. The main result is a dynamical model of loop gravity that agrees with general relativity and is well-suited for quantization using existing methods.

  14. Material Balance Based Modeling of BLSS with Matlab/Simulink. The MEliSSA Loop Case in Steady-State Conditions

    NASA Astrophysics Data System (ADS)

    Poughon, L.; Farges-Haddani, B.; Gros, J. B.; Du, C. G.

    Solving material balances in Biological Life Support Systems BLSS affords mass flow rates and chemical elements C H O N S P etc in all parts of these very intricate and complex systems this helps defining and optimizing the performance of the entire recycling loop in terms of closedness and necessary flow inputs The complete MELiSSA loop was modeled using MatLab Simulink and a mass balance simulator for the loop was released In order to build the complete MELiSSA loop material balance simulator with Matlab Simulink it was necessary 1- To establish steady-state models on the basis of mass-balances and elements-balances for each compartment and each subsystem of the loop for biological processes in the MELiSSA compartments within the loop stoichiometric equations including biomass were derived 2- To develop for each compartments and subsystems the associated Matlab Simulink S-blocks in which models are included 3- To assemble the different S-blocks of the loop flowchart giving as a result the flow rates in the entire recycling loop The simulation parameters are easily managed using the graphical dialog boxes The simulator is used to test the behavior of the loop in different operating conditions typically by varying the composition of the food produced in the loop

  15. Closed-loop neurostimulation: the clinical experience.

    PubMed

    Sun, Felice T; Morrell, Martha J

    2014-07-01

    Neurostimulation is now an established therapy for the treatment of movement disorders, pain, and epilepsy. While most neurostimulation systems available today provide stimulation in an open-loop manner (i.e., therapy is delivered according to preprogrammed settings and is unaffected by changes in the patient's clinical symptoms or in the underlying disease), closed-loop neurostimulation systems, which modulate or adapt therapy in response to physiological changes, may provide more effective and efficient therapy. At present, few such systems exist owing to the complexities of designing and implementing implantable closed-loop systems. This review focuses on the clinical experience of four implantable closed-loop neurostimulation systems: positional-adaptive spinal cord stimulation for treatment of pain, responsive cortical stimulation for treatment of epilepsy, closed-loop vagus nerve stimulation for treatment of epilepsy, and concurrent sensing and stimulation for treatment of Parkinson disease. The history that led to the development of the closed-loop systems, the sensing, detection, and stimulation technology that closes the loop, and the clinical experiences are presented.

  16. Mitotic chromosome compaction via active loop extrusion

    NASA Astrophysics Data System (ADS)

    Goloborodko, Anton; Imakaev, Maxim; Marko, John; Mirny, Leonid; MIT-Northwestern Team

    During cell division, two copies of each chromosome are segregated from each other and compacted more than hundred-fold into the canonical X-shaped structures. According to earlier microscopic observations and the recent Hi-C study, chromosomes are compacted into arrays of consecutive loops of ~100 kilobases. Mechanisms that lead to formation of such loop arrays are largely unknown. Here we propose that, during cell division, chromosomes can be compacted by enzymes that extrude loops on chromatin fibers. First, we use computer simulations and analytical modeling to show that a system of loop-extruding enzymes on a chromatin fiber self-organizes into an array of consecutive dynamic loops. Second, we model the process of loop extrusion in 3D and show that, coupled with the topo II strand-passing activity, it leads to robust compaction and segregation of sister chromatids. This mechanism of chromosomal condensation and segregation does not require additional proteins or specific DNA markup and is robust against variations in the number and properties of such loop extruding enzymes. Work at NU was supported by the NSF through Grants DMR-1206868 and MCB-1022117, and by the NIH through Grants GM105847 and CA193419. Work at MIT was supported by the NIH through Grants GM114190 R01HG003143.

  17. Bootstrapping an NMHV amplitude through three loops

    NASA Astrophysics Data System (ADS)

    Dixon, Lance J.; von Hippel, Matt

    2014-10-01

    We extend the hexagon function bootstrap to the next-to-maximally-helicity-violating (NMHV) configuration for six-point scattering in planar = 4 super-Yang-Mills theory at three loops. Constraints from the differential equation, from the operator product expansion (OPE) for Wilson loops with operator insertions, and from multi-Regge factorization, lead to a unique answer for the three-loop ratio function. The three-loop result also predicts additional terms in the OPE expansion, as well as the behavior of NMHV amplitudes in the multi-Regge limit at one higher logarithmic accuracy (NNLL) than was used as input. Both predictions are in agreement with recent results from the flux-tube approach. We also study the multi-particle factorization of multi-loop amplitudes for the first time. We find that the function controlling this factorization is purely logarithmic through three loops. We show that a function U , which is closely related to the parity-even part of the ratio function V , is remarkably simple; only five of the nine possible final entries in its symbol are non-vanishing. We study the analytic and numerical behavior of both the parity-even and parity-odd parts of the ratio function on simple lines traversing the space of cross ratios ( u, v, w), as well as on a few two-dimensional planes. Finally, we present an empirical formula for V in terms of elements of the coproduct of the six-gluon MHV remainder function R 6 at one higher loop, which works through three loops for V (four loops for R 6).

  18. Application of loop analysis for evaluation of malaria control interventions

    PubMed Central

    2014-01-01

    Background Despite continuous efforts and recent rapid expansion in the financing and implementation of malaria control interventions, malaria still remains one of the most devastating global health issues. Even in countries that have been successful in reducing the incidence of malaria, malaria control is becoming more challenging because of the changing epidemiology of malaria and waning community participation in control interventions. In order to improve the effectiveness of interventions and to promote community understanding of the necessity of continued control efforts, there is an urgent need to develop new methodologies that examine the mechanisms by which community-based malaria interventions could reduce local malaria incidence. Methods This study demonstrated how the impact of community-based malaria control interventions on malaria incidence can be examined in complex systems by qualitative analysis combined with an extensive review of literature. First, sign digraphs were developed through loop analysis to analyse seven interventions: source reduction, insecticide/larvicide use, biological control, treatment with anti-malarials, insecticide-treated mosquito net/long-lasting insecticidal net, non-chemical personal protection measures, and educational intervention. Then, for each intervention, the sign digraphs and literature review were combined to analyse a variety of pathways through which the intervention can influence local malaria incidence as well as interactions between variables involved in the system. Through loop analysis it is possible to see whether increases in one variable qualitatively increases or decreases other variables or leaves them unchanged and the net effect of multiple, interacting variables. Results Qualitative analysis, specifically loop analysis, can be a useful tool to examine the impact of community-based malaria control interventions. Without relying on numerical data, the analysis was able to describe pathways through

  19. The complete mitochondrial genome of the pink stem borer, Sesamia inferens, in comparison with four other Noctuid moths.

    PubMed

    Chai, Huan-Na; Du, Yu-Zhou

    2012-01-01

    The complete 15,413-bp mitochondrial genome (mitogenome) of Sesamia inferens (Walker) (Lepidoptera: Noctuidae) was sequenced and compared with those of four other noctuid moths. All of the mitogenomes analyzed displayed similar characteristics with respect to gene content, genome organization, nucleotide comparison, and codon usages. Twelve-one protein-coding genes (PCGs) utilized the standard ATN, but the cox1 gene used CGA as the initiation codon; cox1, cox2, and nad4 genes had the truncated termination codon T in the S. inferens mitogenome. All of the tRNA genes had typical cloverleaf secondary structures except for trnS1(AGN), in which the dihydrouridine (DHU) arm did not form a stable stem-loop structure. Both the secondary structures of rrnL and rrnS genes inferred from the S. inferens mitogenome closely resembled those of other noctuid moths. In the A+T-rich region, the conserved motif "ATAGA" followed by a long T-stretch was observed in all noctuid moths, but other specific tandem-repeat elements were more variable. Additionally, the S. inferens mitogenome contained a potential stem-loop structure, a duplicated 17-bp repeat element, a decuplicated segment, and a microsatellite "(AT)(7)", without a poly-A element upstream of the trnM in the A+T-rich region. Finally, the phylogenetic relationships were reconstructed based on amino acid sequences of mitochondrial 13 PCGs, which support the traditional morphologically based view of relationships within the Noctuidae.

  20. Frequency multiplexed flux locked loop architecture providing an array of DC SQUIDS having both shared and unshared components

    DOEpatents

    Ganther, Jr., Kenneth R.; Snapp, Lowell D.

    2002-01-01

    Architecture for frequency multiplexing multiple flux locked loops in a system comprising an array of DC SQUID sensors. The architecture involves dividing the traditional flux locked loop into multiple unshared components and a single shared component which, in operation, form a complete flux locked loop relative to each DC SQUID sensor. Each unshared flux locked loop component operates on a different flux modulation frequency. The architecture of the present invention allows a reduction from 2N to N+1 in the number of connections between the cryogenic DC SQUID sensors and their associated room temperature flux locked loops. Furthermore, the 1.times.N architecture of the present invention can be paralleled to form an M.times.N array architecture without increasing the required number of flux modulation frequencies.

  1. Detecting neutrino magnetic moments with conducting loops

    NASA Astrophysics Data System (ADS)

    Apyan, Aram; Apyan, Armen; Schmitt, Michael

    2008-02-01

    It is well established that neutrinos have mass, yet it is very difficult to measure those masses directly. Within the standard model of particle physics, neutrinos will have an intrinsic magnetic moment proportional to their mass. We examine the possibility of detecting the magnetic moment using a conducting loop. According to Faraday’s law of induction, a magnetic dipole passing through a conducting loop induces an electromotive force in the loop. We compute this electromotive force for neutrinos in several cases, based on a fully covariant formulation of the problem. We discuss prospects for a real experiment, as well as the possibility to test the relativistic formulation of intrinsic magnetic moments.

  2. Loop-quantum-gravity vertex amplitude.

    PubMed

    Engle, Jonathan; Pereira, Roberto; Rovelli, Carlo

    2007-10-19

    Spin foam models are hoped to provide the dynamics of loop-quantum gravity. However, the most popular of these, the Barrett-Crane model, does not have the good boundary state space and there are indications that it fails to yield good low-energy n-point functions. We present an alternative dynamics that can be derived as a quantization of a Regge discretization of Euclidean general relativity, where second class constraints are imposed weakly. Its state space matches the SO(3) loop gravity one and it yields an SO(4)-covariant vertex amplitude for Euclidean loop gravity.

  3. Parallel Digital Phase-Locked Loops

    NASA Technical Reports Server (NTRS)

    Sadr, Ramin; Shah, Biren N.; Hinedi, Sami M.

    1995-01-01

    Wide-band microwave receivers of proposed type include digital phase-locked loops in which band-pass filtering and down-conversion of input signals implemented by banks of multirate digital filters operating in parallel. Called "parallel digital phase-locked loops" to distinguish them from other digital phase-locked loops. Systems conceived as cost-effective solution to problem of filtering signals at high sampling rates needed to accommodate wide input frequency bands. Each of M filters process 1/M of spectrum of signal.

  4. Elimination of Thermodynamically Infeasible Loops in Steady-State Metabolic Models

    PubMed Central

    Schellenberger, Jan; Lewis, Nathan E.; Palsson, Bernhard Ø.

    2011-01-01

    The constraint-based reconstruction and analysis (COBRA) framework has been widely used to study steady-state flux solutions in genome-scale metabolic networks. One shortcoming of current COBRA methods is the possible violation of the loop law in the computed steady-state flux solutions. The loop law is analogous to Kirchhoff's second law for electric circuits, and states that at steady state there can be no net flux around a closed network cycle. Although the consequences of the loop law have been known for years, it has been computationally difficult to work with. Therefore, the resulting loop-law constraints have been overlooked. Here, we present a general mixed integer programming approach called loopless COBRA (ll-COBRA), which can be used to eliminate all steady-state flux solutions that are incompatible with the loop law. We apply this approach to improve flux predictions on three common COBRA methods: flux balance analysis, flux variability analysis, and Monte Carlo sampling of the flux space. Moreover, we demonstrate that the imposition of loop-law constraints with ll-COBRA improves the consistency of simulation results with experimental data. This method provides an additional constraint for many COBRA methods, enabling the acquisition of more realistic simulation results. PMID:21281568

  5. The behavior of transverse waves in nonuniform solar flux tubes. II. Implications for coronal loop seismology

    SciTech Connect

    Soler, Roberto; Terradas, Jaume; Oliver, Ramón; Goossens, Marcel

    2014-02-01

    The seismology of coronal loops using observations of damped transverse oscillations in combination with results from theoretical models is a tool to indirectly infer physical parameters in the solar atmospheric plasma. Existing seismology schemes based on approximations of the period and damping time of kink oscillations are often used beyond their theoretical range of applicability. These approximations assume that the variation of density across the loop is confined to a nonuniform layer much thinner than the radius of the loop, but the results of the inversion problem often do not satisfy this preliminary hypothesis. Here, we determine the accuracy of the analytic approximations of the period and damping time, and the impact on seismology estimates when largely nonuniform loops are considered. We find that the accuracy of the approximations when used beyond their range of applicability is strongly affected by the form of the density profile across the loop, that is observationally unknown and so must be arbitrarily imposed as part of the theoretical model. The error associated with the analytic approximations can be larger than 50% even for relatively thin nonuniform layers. This error directly affects the accuracy of approximate seismology estimates compared to actual numerical inversions. In addition, assuming different density profiles can produce noncoincident intervals of the seismic variables in inversions of the same event. The ignorance about the true shape of density variation across the loop is an important source of error that may dispute the reliability of parameters seismically inferred assuming an ad hoc density profile.

  6. Homework Completion at the Secondary School Level: A Multilevel Analysis

    ERIC Educational Resources Information Center

    Xu, Jianzhong

    2011-01-01

    The author aimed to test empirical models of variables posited to predict homework completion at the secondary school level. Student- and class-level predictors of homework completion were analyzed in a survey of 1,046 8th-grade students from 63 classes and of 849 11th-grade students from 48 classes. Most of the variance in homework completion…

  7. DNA looping increases the range of bistability in a stochastic model of the lac genetic switch

    NASA Astrophysics Data System (ADS)

    Earnest, Tyler M.; Roberts, Elijah; Assaf, Michael; Dahmen, Karin; Luthey-Schulten, Zaida

    2013-04-01

    Conditions and parameters affecting the range of bistability of the lac genetic switch in Escherichia coli are examined for a model which includes DNA looping interactions with the lac repressor and a lactose analogue. This stochastic gene-mRNA-protein model of the lac switch describes DNA looping using a third transcriptional state. We exploit the fast bursting dynamics of mRNA by combining a novel geometric burst extension with the finite state projection method. This limits the number of protein/mRNA states, allowing for an accelerated search of the model's parameter space. We evaluate how the addition of the third state changes the bistability properties of the model and find a critical region of parameter space where the phenotypic switching occurs in a range seen in single molecule fluorescence studies. Stochastic simulations show induction in the looping model is preceded by a rare complete dissociation of the loop followed by an immediate burst of mRNA rather than a slower build up of mRNA as in the two-state model. The overall effect of the looped state is to allow for faster switching times while at the same time further differentiating the uninduced and induced phenotypes. Furthermore, the kinetic parameters are consistent with free energies derived from thermodynamic studies suggesting that this minimal model of DNA looping could have a broader range of application.

  8. Ground Source Heat Pump Sub-Slab Heat Exchange Loop Performance in a Cold Climate

    SciTech Connect

    Mittereder, N.; Poerschke, A.

    2013-11-01

    This report presents a cold-climate project that examines an alternative approach to ground source heat pump (GSHP) ground loop design. The innovative ground loop design is an attempt to reduce the installed cost of the ground loop heat exchange portion of the system by containing the entire ground loop within the excavated location beneath the basement slab. Prior to the installation and operation of the sub-slab heat exchanger, energy modeling using TRNSYS software and concurrent design efforts were performed to determine the size and orientation of the system. One key parameter in the design is the installation of the GSHP in a low-load home, which considerably reduces the needed capacity of the ground loop heat exchanger. This report analyzes data from two cooling seasons and one heating season. Upon completion of the monitoring phase, measurements revealed that the initial TRNSYS simulated horizontal sub-slab ground loop heat exchanger fluid temperatures and heat transfer rates differed from the measured values. To determine the cause of this discrepancy, an updated model was developed utilizing a new TRNSYS subroutine for simulating sub-slab heat exchangers. Measurements of fluid temperature, soil temperature, and heat transfer were used to validate the updated model.

  9. DNA looping increases the range of bistability in a stochastic model of the lac genetic switch.

    PubMed

    Earnest, Tyler M; Roberts, Elijah; Assaf, Michael; Dahmen, Karin; Luthey-Schulten, Zaida

    2013-04-01

    Conditions and parameters affecting the range of bistability of the lac genetic switch in Escherichia coli are examined for a model which includes DNA looping interactions with the lac repressor and a lactose analogue. This stochastic gene-mRNA-protein model of the lac switch describes DNA looping using a third transcriptional state. We exploit the fast bursting dynamics of mRNA by combining a novel geometric burst extension with the finite state projection method. This limits the number of protein/mRNA states, allowing for an accelerated search of the model's parameter space. We evaluate how the addition of the third state changes the bistability properties of the model and find a critical region of parameter space where the phenotypic switching occurs in a range seen in single molecule fluorescence studies. Stochastic simulations show induction in the looping model is preceded by a rare complete dissociation of the loop followed by an immediate burst of mRNA rather than a slower build up of mRNA as in the two-state model. The overall effect of the looped state is to allow for faster switching times while at the same time further differentiating the uninduced and induced phenotypes. Furthermore, the kinetic parameters are consistent with free energies derived from thermodynamic studies suggesting that this minimal model of DNA looping could have a broader range of application.

  10. Predictors of completed childhood vaccination in Bolivia

    PubMed Central

    Osetinsky, Brianna; Gaydos, Laura M; Leon, Juan S

    2015-01-01

    This project examines how access issues, ethnicity, and geographic region affect vaccination of children by two years of age in Bolivia. Bolivia’s rich variation in culture and geography results in unequal healthcare utilization even for basic interventions such as childhood vaccination. This study utilizes secondary data from the 2008 Demographic and Health Survey for Bolivia to examine predictors of vaccination completion in children by two years of age. Using logistic regression methods, we control for health system variables (difficulty getting to a health center and type of health center as well as demographic and socio-economic covariates). The results indicated that children whose parents reported distance as a problem in obtaining health care were less likely to have completed all vaccinations. Ethnicity was not independently statistically significant, however, in a sub-analysis, people from the Quechua ethnic group were more likely to report ‘distance as a problem in obtaining healthcare.’ Surprisingly, living in a rural environment has a protective effect on completed vaccinations. However, geographic region did predict significant differences in the probability that children would be fully vaccinated; children in the region with the lowest vaccination completion coverage were 80% less likely to have completed vaccination compared to children in the best performing region, which may indicate unequal access and utilization of health services nationally. Further study of regional differences, urbanicity, and distance as a healthcare access problem will help refine implications for the Bolivian health system. PMID:26609338

  11. Hierarchical loop detection for mobile outdoor robots

    NASA Astrophysics Data System (ADS)

    Lang, Dagmar; Winkens, Christian; Häselich, Marcel; Paulus, Dietrich

    2012-01-01

    Loop closing is a fundamental part of 3D simultaneous localization and mapping (SLAM) that can greatly enhance the quality of long-term mapping. It is essential for the creation of globally consistent maps. Conceptually, loop closing is divided into detection and optimization. Recent approaches depend on a single sensor to recognize previously visited places in the loop detection stage. In this study, we combine data of multiple sensors such as GPS, vision, and laser range data to enhance detection results in repetitively changing environments that are not sufficiently explained by a single sensor. We present a fast and robust hierarchical loop detection algorithm for outdoor robots to achieve a reliable environment representation even if one or more sensors fail.

  12. A magnetohydrodynamic theory of coronal loop transients

    NASA Technical Reports Server (NTRS)

    Yeh, T.

    1982-01-01

    The physical and geometrical characteristics of solar coronal loop transients are described in an MHD model based on Archimedes' MHD buoyancy force. The theory was developed from interpretation of coronagraphic data, particularly from Skylab. The brightness of a loop is taken to indicate the electron density, and successive pictures reveal the electron enhancement in different columns. The forces which lift the loop off the sun surface are analyzed as an MHD buoyancy force affecting every mass element by imparting an inertial force necessary for heliocentrifugal motion. Thermal forces are responsible for transferring the ambient stress to the interior of the loop to begin the process. The kinematic and hydrostatic buoyancy overcome the gravitational force, and a flux rope can then curve upward, spiralling like a corkscrew with varying cross section around the unwinding solar magnetic field lines.

  13. Mathematical Modeling of Loop Heat Pipes

    NASA Technical Reports Server (NTRS)

    Kaya, Tarik; Ku, Jentung; Hoang, Triem T.; Cheung, Mark L.

    1998-01-01

    The primary focus of this study is to model steady-state performance of a Loop Heat Pipe (LHP). The mathematical model is based on the steady-state energy balance equations at each component of the LHP. The heat exchange between each LHP component and the surrounding is taken into account. Both convection and radiation environments are modeled. The loop operating temperature is calculated as a function of the applied power at a given loop condition. Experimental validation of the model is attempted by using two different LHP designs. The mathematical model is tested at different sink temperatures and at different elevations of the loop. Tbc comparison of the calculations and experimental results showed very good agreement (within 3%). This method proved to be a useful tool in studying steady-state LHP performance characteristics.

  14. Four-loop screened perturbation theory

    NASA Astrophysics Data System (ADS)

    Andersen, Jens O.; Kyllingstad, Lars

    2008-10-01

    We study the thermodynamics of massless ϕ4-theory using screened perturbation theory. In this method, the perturbative expansion is reorganized by adding and subtracting a thermal mass term in the Lagrangian. We calculate the free energy through four loops expanding in a double power expansion in m/T and g2, where m is the thermal mass and g is the coupling constant. The expansion is truncated at order g7 and the loop expansion is shown to have better convergence properties than the weak-coupling expansion. The free energy at order g6 involves the four-loop triangle sum-integral evaluated by Gynther, Laine, Schröder, Torrero, and Vuorinen using the methods developed by Arnold and Zhai. The evaluation of the free energy at order g7 requires the evaluation of a nontrivial three-loop sum-integral, which we calculate by the same methods.

  15. Open-loop digital frequency multiplier

    NASA Technical Reports Server (NTRS)

    Moore, R. C.

    1977-01-01

    Monostable multivibrator is implemented by using digital integrated circuits where multiplier constant is too large for conventional phase-locked-loop integrated circuit. A 400 Hz clock is generated by divide-by-N counter from 1 Hz timing reference.

  16. CHY loop integrands from holomorphic forms

    NASA Astrophysics Data System (ADS)

    Gomez, Humberto; Mizera, Sebastian; Zhang, Guojun

    2017-03-01

    Recently, the Cachazo-He-Yuan (CHY) approach for calculating scattering amplitudes has been extended beyond tree level. In this paper, we introduce a way of constructing CHY integrands for Φ3 theory up to two loops from holomorphic forms on Riemann surfaces. We give simple rules for translating Feynman diagrams into the corresponding CHY integrands. As a complementary result, we extend the Λ-algorithm, originally introduced in arXiv:1604.05373, to two loops. Using this approach, we are able to analytically verify our prescription for the CHY integrands up to seven external particles at two loops. In addition, it gives a natural way of extending to higher-loop orders.

  17. Complete mitochondrial genome of Cygnus olor (Aves, Anseriformes, Anatidae).

    PubMed

    Park, Chang Eon; Park, Gun-Seok; Kwak, Yunyoung; Hong, Sung-Jun; Khan, Abdur Rahim; Jung, Byung Kwon; Park, Yeong-Jun; Kim, Jong-Guk; Park, Hee Cheon; Shin, Jae-Ho

    2016-09-01

    The complete mitochondrial genome of Cygnus olor (Aves, Anseriformes, Anatidae) was revealed in this study. Total 16 739 base pairs (bp) of this mitogenome encoded genes for 13 protein coding genes (PCGs), two ribosomal RNAs (rRNAs), 22 transfer RNAs (tRNAs) and a D-loop (control region). The 12S rRNA and 16S rRNA genes are located between tRNA-Phe and tRNA-Leu (UUR) and segmentalized by the tRNA-Val. D-loop is located between tRNA-Glu and tRNA-Phe. The overall base composition of C. olor is G + C: 47.8%, A + T: 52.2%, apparently with a slight AT bias. Following the phylogenetic analysis, the C. olor was closed to Anser cygnoides.

  18. A multiple-pass ring oscillator based dual-loop phase-locked loop

    NASA Astrophysics Data System (ADS)

    Danfeng, Chen; Junyan, Ren; Jingjing, Deng; Wei, Li; Ning, Li

    2009-10-01

    A dual-loop phase-locked loop (PLL) for wideband operation is proposed. The dual-loop architecture combines a coarse-tuning loop with a fine-tuning one, enabling a wide tuning range and low voltage-controlled oscillator (VCO) gain without poisoning phase noise and reference spur suppression performance. An analysis of the phase noise and reference spur of the dual-loop PLL is emphasized. A novel multiple-pass ring VCO is designed for the dual-loop application. It utilizes both voltage-control and current-control simultaneously in the delay cell. The PLL is fabricated in Jazz 0.18-μm RF CMOS technology. The measured tuning range is from 4.2 to 5.9 GHz. It achieves a low phase noise of -99 dBc/Hz @ 1 MHz offset from a 5.5 GHz carrier.

  19. Deployable radiator with flexible line loop

    NASA Technical Reports Server (NTRS)

    Keeler, Bryan V. (Inventor); Lehtinen, Arthur Mathias (Inventor); McGee, Billy W. (Inventor)

    2003-01-01

    Radiator assembly (10) for use on a spacecraft (12) is provided including at least one radiator panel assembly (26) repeatably movable between a panel stowed position (28) and a panel deployed position (36), at least two flexible lines (40) in fluid communication with the at least one radiator panel assembly (26) and repeatably movable between a stowage loop (42) and a flattened deployed loop (44).

  20. Miniature loops in the solar corona

    NASA Astrophysics Data System (ADS)

    Barczynski, K.; Peter, H.; Savage, S. L.

    2017-03-01

    Context. Magnetic loops filled with hot plasma are the main building blocks of the solar corona. Usually they have lengths of the order of the barometric scale height in the corona that is 50 Mm. Aims: Previously it has been suggested that miniature versions of hot loops exist. These would have lengths of only 1 Mm barely protruding from the chromosphere and spanning across just one granule in the photosphere. Such short loops are well established at transition region temperatures (0.1 MK), and we investigate if such miniature loops also exist at coronal temperatures (>1 MK). Methods: We used extreme UV (EUV) imaging observations from the High-resolution Coronal Imager (Hi-C) at an unprecedented spatial resolution of 0.3'' to 0.4''. Together with EUV imaging and magnetogram data from the Solar Dynamics Observatory (SDO) and X-Ray Telescope (XRT) data from Hinode we investigated the spatial, temporal and thermal evolution of small loop-like structures in the solar corona above a plage region close to an active region and compared this to a moss area within the active region. Results: We find that the size, motion and temporal evolution of the loop-like features are consistent with photospheric motions, suggesting a close connection to the photospheric magnetic field. Aligned magnetograms show that one of their endpoints is rooted at a magnetic concentration. Their thermal structure, as revealed together with the X-ray observations, shows significant differences to moss-like features. Conclusions: Considering different scenarios, these features are most probably miniature versions of hot loops rooted at magnetic concentrations at opposite sides of a granule in small emerging magnetic loops (or flux tubes).

  1. Simple system for locating ground loops.

    PubMed

    Bellan, P M

    2007-06-01

    A simple low-cost system for rapid identification of the cables causing ground loops in complex instrumentation configurations is described. The system consists of an exciter module that generates a 100 kHz ground loop current and a detector module that determines which cable conducts this test current. Both the exciter and detector are magnetically coupled to the ground circuit so there is no physical contact to the instrumentation system under test.

  2. Can Chemical Looping Combustion Use CFB Technology?

    SciTech Connect

    Gamwo, I.K.

    2006-11-01

    Circulating Fluidized Bed (CFB) technology has demonstrated an unparalleled ability to achieve low SO2 and NOx emissions for coal-fired power plants without CO2 capture. Chemical Looping combustion (CLC) is a novel fuel combustion technology which appears as a leading candidate in terms of competitiveness for CO2 removal from flue gas. This presentaion deals with the adaptation of circulating fluidized bed technology to Chemical looping combustion

  3. Onset of inflation in loop quantum cosmology

    SciTech Connect

    Germani, Cristiano; Nelson, William; Sakellariadou, Mairi

    2007-08-15

    Using a Liouville measure, similar to the one proposed recently by Gibbons and Turok, we investigate the probability that single-field inflation with a polynomial potential can last long enough to solve the shortcomings of the standard hot big bang model, within the semiclassical regime of loop quantum cosmology. We conclude that, for such a class of inflationary models and for natural values of the loop quantum cosmology parameters, a successful inflationary scenario is highly improbable.

  4. Multiple Flow Loop SCADA System Implemented on the Production Prototype Loop

    SciTech Connect

    Baily, Scott A.; Dalmas, Dale Allen; Wheat, Robert Mitchell; Woloshun, Keith Albert; Dale, Gregory E.

    2015-11-16

    The following report covers FY 15 activities to develop supervisory control and data acquisition (SCADA) system for the Northstar Moly99 production prototype gas flow loop. The goal of this effort is to expand the existing system to include a second flow loop with a larger production-sized blower. Besides testing the larger blower, this system will demonstrate the scalability of our solution to multiple flow loops.

  5. Space Station evolution study oxygen loop closure

    NASA Technical Reports Server (NTRS)

    Wood, M. G.; Delong, D.

    1993-01-01

    In the current Space Station Freedom (SSF) Permanently Manned Configuration (PMC), physical scars for closing the oxygen loop by the addition of oxygen generation and carbon dioxide reduction hardware are not included. During station restructuring, the capability for oxygen loop closure was deferred to the B-modules. As such, the ability to close the oxygen loop in the U.S. Laboratory module (LAB A) and the Habitation A module (HAB A) is contingent on the presence of the B modules. To base oxygen loop closure of SSF on the funding of the B-modules may not be desirable. Therefore, this study was requested to evaluate the necessary hooks and scars in the A-modules to facilitate closure of the oxygen loop at or subsequent to PMC. The study defines the scars for oxygen loop closure with impacts to cost, weight and volume and assesses the effects of byproduct venting. In addition, the recommended scenarios for closure with regard to topology and packaging are presented.

  6. Integration of calcium and chemical looping combustion using composite CaO/CuO-based materials.

    PubMed

    Manovic, Vasilije; Anthony, Edward J

    2011-12-15

    Calcium looping cycles (CaL) and chemical looping combustion (CLC) are two new, developing technologies for reduction of CO(2) emissions from plants using fossil fuels for energy production, which are being intensively examined. Calcium looping is a two-stage process, which includes oxy-fuel combustion for sorbent regeneration, i.e., generation of a concentrated CO(2) stream. This paper discuss the development of composite materials which can use copper(II)-oxide (CuO) as an oxygen carrier to provide oxygen for the sorbent regeneration stage of calcium looping. In other words, the work presented here involves integration of calcium looping and chemical looping into a new class of postcombustion CO(2) capture processes designated as integrated CaL and CLC (CaL-CLC or Ca-Cu looping cycles) using composite pellets containing lime (CaO) and CuO together with the addition of calcium aluminate cement as a binder. Their activity was tested in a thermogravimetric analyzer (TGA) during calcination/reduction/oxidation/carbonation cycles. The calcination/reduction typically was performed in methane (CH(4)), and the oxidation/carbonation stage was carried out using a gas mixture containing both CO(2) and O(2). It was confirmed that the material synthesized is suitable for the proposed cycles; with the very favorable finding that reduction/oxidation of the oxygen carrier is complete. Various schemes for the Ca-Cu looping process have been explored here that would be compatible with these new composite materials, along with some different possibilities for flow directions among carbonator, calciner, and air reactor.

  7. Numerical Simulations of Power Law Heating Functions for Quiescent Loops: Stability and Observables

    NASA Astrophysics Data System (ADS)

    Martens, P. C.; Winter, H. D.; Munetsi-Mugomba, K.

    2007-12-01

    We present the numerical simulations of quiescent coronal loops with heating functions that are power law functions of pressure and temperature. These simulations are made using a time-dependent, 1D hydrodynamics code with heating functions that are treated as dynamic variables which are constantly re- evaluated during the loops' lifetimes. These numerical simulations provide a stability test for the analytical solutions formulated by Martens (2007, submitted) for the same heating functions. TRACE and XRT datasets are simulated to determine if present observables can provide adequate information to discriminate between power law heating functions.

  8. Structure of a cardiotoxic phospholipase A(2) from Ophiophagus hannah with the "pancreatic loop".

    PubMed

    Zhang, Hai-Long; Xu, Su-Juan; Wang, Qiu-Yan; Song, Shi-Ying; Shu, Yu-Yan; Lin, Zheng-Jiong

    2002-06-01

    The crystal structure of an acidic phospholipase A(2) from Ophiophagus hannah (king cobra) has been determined by molecular replacement at 2.6-A resolution to a crystallographic R factor of 20.5% (R(free)=23.3%) with reasonable stereochemistry. The venom enzyme contains an unusual "pancreatic loop." The conformation of the loop is well defined and different from those in pancreas PLA(2), showing its structural variability. This analysis provides the first structure of a PLA(2)-type cardiotoxin. The sites related to the cardiotoxic and myotoxic activities are explored and the oligomer observed in the crystalline state is described.

  9. Beat to beat variability in cardiovascular variables: noise or music?

    NASA Technical Reports Server (NTRS)

    Appel, M. L.; Berger, R. D.; Saul, J. P.; Smith, J. M.; Cohen, R. J.

    1989-01-01

    Cardiovascular variables such as heart rate, arterial blood pressure, stroke volume and the shape of electrocardiographic complexes all fluctuate on a beat to beat basis. These fluctuations have traditionally been ignored or, at best, treated as noise to be averaged out. The variability in cardiovascular signals reflects the homeodynamic interplay between perturbations to cardiovascular function and the dynamic response of the cardiovascular regulatory systems. Modern signal processing techniques provide a means of analyzing beat to beat fluctuations in cardiovascular signals, so as to permit a quantitative, noninvasive or minimally invasive method of assessing closed loop hemodynamic regulation and cardiac electrical stability. This method promises to provide a new approach to the clinical diagnosis and management of alterations in cardiovascular regulation and stability.

  10. The constant current loop - A new paradigm for resistance signal conditioning

    NASA Technical Reports Server (NTRS)

    Anderson, Karl F.

    1993-01-01

    A practical single constant current loop circuit for the signal conditioning of variable-resistance transducers has been synthesized, analyzed, and demonstrated. The strain gage and the resistance temperature device are examples of variable-resistance sensors. Lead wires connect variable-resistance sensors to remotely located signal-conditioning hardware. The presence of lead wires in the conventional Wheatstone bridge signal-conditioning circuit introduces undesired effects that reduce the quality of the data from the remote sensors. A practical approach is presented for suppressing essentially all lead wire resistance effects while indicating only the change in resistance value. An adaptation of the current loop circuit is presented that simultaneously provides an output signal voltage directly proportional to transducer resistance change and provides temperature information that is unaffected by transducer and lead wire resistance variations.

  11. Glucose Variability

    PubMed Central

    Le Floch, Jean-Pierre; Kessler, Laurence

    2016-01-01

    Background: Glucose variability has been suspected to be a major factor of diabetic complications. Several indices have been proposed for measuring glucose variability, but their interest remains discussed. Our aim was to compare different indices. Methods: Glucose variability was studied in 150 insulin-treated diabetic patients (46% men, 42% type 1 diabetes, age 52 ± 11 years) using a continuous glucose monitoring system (668 ± 564 glucose values; mean glucose value 173 ± 38 mg/dL). Results from the mean, the median, different indices (SD, MAGE, MAG, glucose fluctuation index (GFI), and percentages of low [<60 mg/dL] and high [>180 mg/dL] glucose values), and ratios (CV = SD/m, MAGE/m, MAG/m, and GCF = GFI/m) were compared using Pearson linear correlations and a multivariate principal component analysis (PCA). Results: CV, MAGE/m (ns), GCF and GFI (P < .05), MAG and MAG/m (P < .01) were not strongly correlated with the mean. The percentage of high glucose values was mainly correlated with indices. The percentage of low glucose values was mainly correlated with ratios. PCA showed 3 main axes; the first was associated with descriptive data (mean, SD, CV, MAGE, MAGE/m, and percentage of high glucose values); the second with ratios MAG/m and GCF and with the percentage of low glucose values; and the third with MAG, GFI, and the percentage of high glucose values. Conclusions: Indices and ratios provide complementary pieces of information associated with high and low glucose values, respectively. The pairs MAG+MAG/m and GFI+GCF appear to be the most reliable markers of glucose variability in diabetic patients. PMID:26880391

  12. QT variability.

    PubMed

    Berger, Ronald D

    2003-01-01

    We hypothesized that temporal lability in ventricular repolarization is a marker for, and is mechanistically related to, increased risk of malignant ventricular arrhythmias. To assess repolarization lability in the surface electrocardiogram, we developed an automated algorithm, based on template matching, to measure beat-to-beat changes in QT interval. We calculate a QT variability index (QTVI) to quantify the relative magnitude of QT interval changes compared to heart rate variability. We found that QTVI is a reproducible measure. It is elevated in patients with ischemic and nonischemic dilated cardiomyopathy compared with age-matched controls (P<.00001). We have also shown that QTVI is elevated in patients with malignant beta-myosin heavy-chain mutations associated with hypertrophic cardiomyopathy. In a study of patients undergoing electrophysiologic testing, QTVI identified patients with cardiac arrest better than electrophysiologic test result and better than other risk stratifiers included in the analysis. QT variability is a marker of electrical disease in the ventricle and may be associated with enhanced risk of life-threatening arrhythmias.

  13. Complete to Compete: Common College Completion Metrics. Technical Guide

    ERIC Educational Resources Information Center

    Reyna, Ryan; Reindl, Travis; Witham, Keith; Stanley, Jeff

    2010-01-01

    Improved college completion rates are critical to the future of the United States, and states must have better data to understand the nature of the challenges they confront or target areas for policy change. The 2010-2011 National Governors Association (NGA) Chair's initiative, "Complete to Compete", recommends that all states collect data from…

  14. Sequence analysis of the complete mitochondrial genome of Youxian sheldrake.

    PubMed

    He, Shao-Ping; Liu, Li-Li; Yu, Qi-Fang; Li, Si; He, Jian-Hua

    2016-01-01

    Youxian sheldrake is excellent native breeds in Hunan province in China. The complete mitochondrial (mt) genome sequence plays an important role in the accurate determination of phylogenetic relationships among metazoans. This is the first study to determine the complete mitochondrial genome sequence of Youxian sheldrake using PCR-based amplification and Sanger sequencing. The characteristic of the entire mitochondrial genome was analyzed in detail, the total length of the mitogenome is 16,605 bp, with the base composition of 29.21% A, 22.18% T, 32.84% C, 15.77% G in the Youxian sheldrake. It contained 2 ribosomal RNA genes, 13 protein-coding genes, 22 transfer RNA genes and a major non-coding control region (D-loop region). The complete mitochondrial genome sequence of Youxian sheldrake provided an important data for further study of the phylogenetics of poultry, and available data for the genetics and breeding.

  15. Simple excision and closure of a distal limb of loop colostomy prolapse by stapler device.

    PubMed

    Masumori, K; Maeda, K; Koide, Y; Hanai, T; Sato, H; Matsuoka, H; Katsuno, H; Noro, T

    2012-04-01

    Stomal prolapse is one of the common complications in transverse colostomy and can be managed conservatively in most cases; however, laparotomy and reconstruction of the stoma may sometimes be required, especially in case of irreducible colostomy prolapse. We have reported a simple local repair with reconstruction of the loop colostomy. We herein report a new more simple technique to avoid laparotomy and allow excision of the irreducible colostomy prolapse and complete closure of the distal limb of loop colostomy when no decompression is required in the distal limb of the stoma. In this procedure, the number of stapler and the time with blood loss for the operation can be saved.

  16. Hanford Tank Farms Waste Feed Flow Loop Phase VI: PulseEcho System Performance Evaluation

    SciTech Connect

    Denslow, Kayte M.; Bontha, Jagannadha R.; Adkins, Harold E.; Jenks, Jeromy WJ; Hopkins, Derek F.

    2012-11-21

    This document presents the visual and ultrasonic PulseEcho critical velocity test results obtained from the System Performance test campaign that was completed in September 2012 with the Remote Sampler Demonstration (RSD)/Waste Feed Flow Loop cold-test platform located at the Monarch test facility in Pasco, Washington. This report is intended to complement and accompany the report that will be developed by WRPS on the design of the System Performance simulant matrix, the analysis of the slurry test sample concentration and particle size distribution (PSD) data, and the design and construction of the RSD/Waste Feed Flow Loop cold-test platform.

  17. Gauge theories in anti-selfdual variables

    NASA Astrophysics Data System (ADS)

    Bochicchio, Marco; Pilloni, Alessandro

    2013-09-01

    Some years ago the Nicolai map, viewed as a change of variables from the gauge connection in a fixed gauge to the anti-selfdual part of the curvature, has been extended by the first named author to pure Yang-Mills from its original definition in = 1 supersymmetric Yang-Mills. We study here the perturbative one-particle irreducible effective action in the anti-selfdual variables of any gauge theory, in particular pure Yang-Mills, QCD and = 1 supersymmetric Yang-Mills. We prove that the one-loop one-particle irreducible effective action of a gauge theory mapped to the anti-selfdual variables in any gauge is identical to the one of the original theory. This is due to the conspiracy between the Jacobian of the change to the anti-selfdual variables and an extra functional determinant that arises from the non-linearity of the coupling of the anti-selfdual curvature to an external source in the Legendre transform that defines the one-particle irreducible effective action. Hence we establish the one-loop perturbative equivalence of the mapped and original theories on the basis of the identity of the one-loop one-particle irreducible effective actions. Besides, we argue that the identity of the perturbative one-particle irreducible effective actions extends order by order in perturbation theory.

  18. LOOP CALCULUS AND BELIEF PROPAGATION FOR Q-ARY ALPHABET: LOOP TOWER

    SciTech Connect

    CHERTKOV, MICHAEL; CHERNYAK, VLADIMIR

    2007-01-10

    Loop calculus introduced in [1], [2] constitutes a new theoretical tool that explicitly expresses symbol Maximum-A-Posteriori (MAP) solution of a general statistical inference problem via a solution of the Belief Propagation (BP) equations. This finding brought a new significance to the BP concept, which in the past was thought of as just a loop-free approximation. In this paper they continue a discussion of the Loop Calculus, partitioning the results into three Sections. In Section 1 they introduce a new formulation of the Loop Calculus in terms of a set of transformations (gauges) that keeping the partition function of the problem invariant. The full expression contains two terms referred to as the 'ground state' and 'excited states' contributions. The BP equations are interpreted as a special (BP) gauge fixing condition that emerges as a special orthogonality constraint between the ground state and excited states, which also selects loop contributions as the only surviving ones among the excited states. In Section 2 they demonstrate how the invariant interpretation of the Loop Calculus, introduced in Section 1, allows a natural extension to the case of a general q-ary alphabet, this is achieved via a loop tower sequential construction. The ground level in the tower is exactly equivalent to assigning one color (out of q available) to the 'ground state' and considering all 'excited' states colored in the remaining (q-1) colors, according to the loop calculus rule. Sequentially, the second level in the tower corresponds to selecting a loop from the previous step, colored in (q-1) colors, and repeating the same ground vs excited states splitting procedure into one and (q-2) colors respectively. The construction proceeds till the full (q-1)-levels deep loop tower (and the corresponding contributions to the partition function) are established. In Section 3 they discuss an ultimate relation between the loop calculus and the Bethe-Free energy variational approach of [3].

  19. An Antibody Loop Replacement Design Feasibility Study and a Loop-Swapped Dimer Structure

    SciTech Connect

    Clark, L.; Boriack-Sjodin, P; Day, E; Eldredge, J; Fitch, C; Jarpe, M; Miller, S; Li, Y; Simon, K; van Vlijmen, H

    2009-01-01

    A design approach was taken to investigate the feasibility of replacing single complementarity determining region (CDR) antibody loops. This approach may complement simpler mutation-based strategies for rational antibody design by expanding conformation space. Enormous crystal structure diversity is available, making CDR loops logical targets for structure-based design. A detailed analysis for the L1 loop shows that each loop length takes a distinct conformation, thereby allowing control on a length scale beyond that accessible to simple mutations. The L1 loop in the anti-VLA1 antibody was replaced with the L2 loop residues longer in an attempt to add an additional hydrogen bond and fill space on the antibody-antigen interface. The designs expressed well, but failed to improve affinity. In an effort to learn more, one design was crystallized and data were collected at 1.9 {angstrom} resolution. The designed L1 loop takes the qualitatively desired conformation; confirming that loop replacement by design is feasible. The crystal structure also shows that the outermost loop (residues Leu51-Ser68) is domain swapped with another monomer. Tryptophan fluorescence measurements were used to monitor unfolding as a function of temperature and indicate that the loop involved in domain swapping does not unfold below 60C. The domain-swapping is not directly responsible for the affinity loss, but is likely a side-effect of the structural instability which may contribute to affinity loss. A second round of design was successful in eliminating the dimerization through mutation of a residue (Leu51Ser) at the joint of the domain-swapped loop.

  20. Detection and Characterization of R Loop Structures.

    PubMed

    Boque-Sastre, Raquel; Soler, Marta; Guil, Sonia

    2017-01-01

    R loops are special three stranded nucleic acid structures that comprise a nascent RNA hybridized with the DNA template strand, leaving a non-template DNA single-stranded. More specifically, R loops form in vivo as G-rich RNA transcripts invade the DNA duplex and anneal to the template strand to generate an RNA:DNA hybrid, leaving the non-template, G-rich DNA strand in a largely single-stranded conformation (Aguilera and Garcia-Muse, Mol Cell 46:115-124, 2012).DNA-RNA hybrids are a natural occurrence within eukaryotic cells, with levels of these hybrids increasing at sites with high transcriptional activity, such as during transcription initiation, repression, and elongation. RNA-DNA hybrids influence genomic instability, and growing evidence points to an important role for R loops in active gene expression regulation (Ginno et al., Mol Cell 45, 814-825, 2012; Sun et al., Science 340: 619-621, 2013; Bhatia et al., Nature 511, 362-365, 2014). Analysis of the occurrence of such structures is therefore of increasing relevance and herein we describe methods for the in vivo and in vitro identification and characterization of R loops in mammalian systems.R loops (DNA:RNA hybrids and the associated single-stranded DNA) have been traditionally associated with threats to genome integrity, making some regions of the genome more prone to DNA-damaging and mutagenic agents. Initially considered to be rare byproducts of transcription, over the last decade accumulating evidence has pointed to a new view in which R loops form more frequently than previously thought. The R loop field has become an increasingly expanded area of research, placing these structures as a major threat to genome stability but also as potential regulators of gene expression. Special interest has arisen as they have also been linked to a variety of diseases, including neurological disorders and cancer, positioning them as potential therapeutic targets [5].

  1. Acquisition Performances Of QPSK Carrier-Tracking Loops

    NASA Technical Reports Server (NTRS)

    Hinedi, Sami M.; Shah, Biren N.

    1992-01-01

    Report presents comparative study of acquisition performances of several types of carrier-signal-tracking loops for reception of quadrature phase-shift keying (QPSK) signals. Loops classified into three types: maximum a-posteriori, (MAP) estimation loop, Costas cross-over loop, and generalized Costas loop. Mathematical models developed. In-phase and quadrature signals generated numerically and processed according to loop algorithms. Results show though MAP loop produces smallest squaring loss at all signal-to-noise ratios, others sometimes exhibit shorter acquisition time and greater probability of acquisition.

  2. The Complete Mitochondrial Genomes of Six Species of Tetranychus Provide Insights into the Phylogeny and Evolution of Spider Mites

    PubMed Central

    Chen, Da-Song; Jin, Peng-Yu; Zhang, Kai-Jun; Ding, Xiu-Lei; Yang, Si-Xia; Ju, Jia-Fei; Zhao, Jing-Yu; Hong, Xiao-Yue

    2014-01-01

    Many spider mites belonging to the genus Tetranychus are of agronomical importance. With limited morphological characters, Tetranychus mites are usually identified by a combination of morphological characteristics and molecular diagnostics. To clarify their molecular evolution and phylogeny, the mitochondrial genomes of the green and red forms of Tetranychus urticae as well as T. kanzawai, T. ludeni, T. malaysiensis, T. phaselus, T. pueraricola were sequenced and compared. The seven mitochondrial genomes are typical circular molecules of about 13,000 bp encoding and they are composed of the complete set of 37 genes that are usually found in metazoans. The order of the mitochondrial (mt) genes is the same as that in the mt genomes of Panonychus citri and P. ulmi, but very different from that in other Acari. The J-strands of the mitochondrial genomes have high (∼84%) A+T contents, negative GC-skews and positive AT-skews. The nucleotide sequence of the cox1 gene, which is commonly used as a taxon barcode and molecular marker, is more highly conserved than the nucleotide sequences of other mitochondrial genes in these seven species. Most tRNA genes in the seven genomes lose the D-arm and/or the T-arm. The functions of these tRNAs need to be evaluated. The mitochondrial genome of T. malaysiensis differs from the other six genomes in having a slightly smaller genome size, a slight difference in codon usage, and a variable loop in place of the T-arm of some tRNAs by a variable loop. A phylogenic analysis shows that T. malaysiensis first split from other Tetranychus species and that the clade of the family Tetranychoidea occupies a basal position in the Trombidiformes. The mt genomes of the green and red forms of T. urticae have limited divergence and short evolutionary distance. PMID:25329165

  3. Open-loop versus closed-loop control of MEMS devices: choices and issues

    NASA Astrophysics Data System (ADS)

    Borovic, B.; Liu, A. Q.; Popa, D.; Cai, H.; Lewis, F. L.

    2005-10-01

    From a controls point of view, micro electromechanical systems (MEMS) can be driven in an open-loop and closed-loop fashion. Commonly, these devices are driven open-loop by applying simple input signals. If these input signals become more complex by being derived from the system dynamics, we call such control techniques pre-shaped open-loop driving. The ultimate step for improving precision and speed of response is the introduction of feedback, e.g. closed-loop control. Unlike macro mechanical systems, where the implementation of the feedback is relatively simple, in the MEMS case the feedback design is quite problematic, due to the limited availability of sensor data, the presence of sensor dynamics and noise, and the typically fast actuator dynamics. Furthermore, a performance comparison between open-loop and closed-loop control strategies has not been properly explored for MEMS devices. The purpose of this paper is to present experimental results obtained using both open- and closed-loop strategies and to address the comparative issues of driving and control for MEMS devices. An optical MEMS switching device is used for this study. Based on these experimental results, as well as computer simulations, we point out advantages and disadvantages of the different control strategies, address the problems that distinguish MEMS driving systems from their macro counterparts, and discuss criteria to choose a suitable control driving strategy.

  4. Students' Understanding of Loops and Nested Loops in Computer Programming: An APOS Theory Perspective

    ERIC Educational Resources Information Center

    Cetin, Ibrahim

    2015-01-01

    The purpose of this study is to explore students' understanding of loops and nested loops concepts. Sixty-three mechanical engineering students attending an introductory programming course participated in the study. APOS (Action, Process, Object, Schema) is a constructivist theory developed originally for mathematics education. This study is the…

  5. Latino College Completion: North Dakota

    ERIC Educational Resources Information Center

    Excelencia in Education (NJ1), 2012

    2012-01-01

    In 2009, Excelencia in Education launched the Ensuring America's Future initiative to inform, organize, and engage leaders in a tactical plan to increase Latino college completion. An executive summary of Latino College Completion in 50 states synthesizes information on 50 state factsheets and builds on the national benchmarking guide. Each…

  6. Latino College Completion: South Dakota

    ERIC Educational Resources Information Center

    Excelencia in Education (NJ1), 2012

    2012-01-01

    In 2009, Excelencia in Education launched the Ensuring America's Future initiative to inform, organize, and engage leaders in a tactical plan to increase Latino college completion. An executive summary of Latino College Completion in 50 states synthesizes information on 50 state factsheets and builds on the national benchmarking guide. Each…

  7. Latino College Completion: New Jersey

    ERIC Educational Resources Information Center

    Excelencia in Education (NJ1), 2012

    2012-01-01

    In 2009, Excelencia in Education launched the Ensuring America's Future initiative to inform, organize, and engage leaders in a tactical plan to increase Latino college completion. An executive summary of Latino College Completion in 50 states synthesizes information on 50 state factsheets and builds on the national benchmarking guide. Each…

  8. Latino College Completion: New Mexico

    ERIC Educational Resources Information Center

    Excelencia in Education (NJ1), 2012

    2012-01-01

    In 2009, Excelencia in Education launched the Ensuring America's Future initiative to inform, organize, and engage leaders in a tactical plan to increase Latino college completion. An executive summary of Latino College Completion in 50 states synthesizes information on 50 state factsheets and builds on the national benchmarking guide. Each…

  9. Latino College Completion: Rhode Island

    ERIC Educational Resources Information Center

    Excelencia in Education (NJ1), 2012

    2012-01-01

    In 2009, Excelencia in Education launched the Ensuring America's Future initiative to inform, organize, and engage leaders in a tactical plan to increase Latino college completion. An executive summary of Latino College Completion in 50 states synthesizes information on 50 state factsheets and builds on the national benchmarking guide. Each…

  10. High School Completion Longitudinal Study

    ERIC Educational Resources Information Center

    Alberta Education, 2009

    2009-01-01

    While Alberta enjoys proven high, world-class results in student achievement, raising high school completion rates is one of the top priorities in improving the provincial education system. The 2011-12 targeted high school completion rate is 82% five years after entering Grade 10--a 2.5% increase from the current average rate of 79.5%. The purpose…

  11. Parameterizing loop fusion for automated empirical tuning

    SciTech Connect

    Zhao, Y; Yi, Q; Kennedy, K; Quinlan, D; Vuduc, R

    2005-12-15

    Traditional compilers are limited in their ability to optimize applications for different architectures because statically modeling the effect of specific optimizations on different hardware implementations is difficult. Recent research has been addressing this issue through the use of empirical tuning, which uses trial executions to determine the optimization parameters that are most effective on a particular hardware platform. In this paper, we investigate empirical tuning of loop fusion, an important transformation for optimizing a significant class of real-world applications. In spite of its usefulness, fusion has attracted little attention from previous empirical tuning research, partially because it is much harder to configure than transformations like loop blocking and unrolling. This paper presents novel compiler techniques that extend conventional fusion algorithms to parameterize their output when optimizing a computation, thus allowing the compiler to formulate the entire configuration space for loop fusion using a sequence of integer parameters. The compiler can then employ an external empirical search engine to find the optimal operating point within the space of legal fusion configurations and generate the final optimized code using a simple code transformation system. We have implemented our approach within our compiler infrastructure and conducted preliminary experiments using a simple empirical search strategy. Our results convey new insights on the interaction of loop fusion with limited hardware resources, such as available registers, while confirming conventional wisdom about the effectiveness of loop fusion in improving application performance.

  12. Bootstrapping the Three-Loop Hexagon

    SciTech Connect

    Dixon, Lance J.; Drummond, James M.; Henn, Johannes M.; /Humboldt U., Berlin /Santa Barbara, KITP

    2011-11-08

    We consider the hexagonal Wilson loop dual to the six-point MHV amplitude in planar N = 4 super Yang-Mills theory. We apply constraints from the operator product expansion in the near-collinear limit to the symbol of the remainder function at three loops. Using these constraints, and assuming a natural ansatz for the symbol's entries, we determine the symbol up to just two undetermined constants. In the multi-Regge limit, both constants drop out from the symbol, enabling us to make a non-trivial confirmation of the BFKL prediction for the leading-log approximation. This result provides a strong consistency check of both our ansatz for the symbol and the duality between Wilson loops and MHV amplitudes. Furthermore, we predict the form of the full three-loop remainder function in the multi-Regge limit, beyond the leading-log approximation, up to a few constants representing terms not detected by the symbol. Our results confirm an all-loop prediction for the real part of the remainder function in multi-Regge 3 {yields} 3 scattering. In the multi-Regge limit, our result for the remainder function can be expressed entirely in terms of classical polylogarithms. For generic six-point kinematics other functions are required.

  13. Congenital preretinal arterial loop: Is it a misnomer?

    PubMed Central

    Raman, Rajiv; Gella, Laxmi; Kazi, M. S.

    2017-01-01

    We describe a case of recurrent spontaneous vitreous haemorrhage due to congenital retinal arterial loop. The pre-optical coherence tomography showed the loop to be intraretinal rather than pre retinal. Thus the term pre retinal arterial loop is a misnomer. The arterial loop is in the superficial layer of retinal nerve fiber layer. We also demonstrated preretinal posterior hyaloid tissue attached on the retinal arterial loop, which may be the cause of traction and spontaneous recurrent VH. PMID:28298870

  14. Linear phase demodulator including a phase locked loop with auxiliary feedback loop

    NASA Technical Reports Server (NTRS)

    Rippy, R. R. (Inventor)

    1976-01-01

    A phase modulated wave that may have no carrier power is demodulated by a phase locked loop including a phase detector for deriving an A.C. data output signal having a magnitude and a phase indicative of the phase of the modulated wave. A feedback loop responsive to the data output signal restores power to the carrier frequency component to the loop. In one embodiment, the feedback loop includes a phase modulator responsive to the phase modulated wave and the data output signal. In a second embodiment, carrier frequency power is restored by differentiating the data output signal and supplying the differentiated signal to an input of a voltage controlled oscillator included in the phase locked loop.

  15. A digital optical phase-locked loop for diode lasers based on field programmable gate array.

    PubMed

    Xu, Zhouxiang; Zhang, Xian; Huang, Kaikai; Lu, Xuanhui

    2012-09-01

    We have designed and implemented a highly digital optical phase-locked loop (OPLL) for diode lasers in atom interferometry. The three parts of controlling circuit in this OPLL, including phase and frequency detector (PFD), loop filter and proportional integral derivative (PID) controller, are implemented in a single field programmable gate array chip. A structure type compatible with the model MAX9382∕MCH12140 is chosen for PFD and pipeline and parallelism technology have been adapted in PID controller. Especially, high speed clock and twisted ring counter have been integrated in the most crucial part, the loop filter. This OPLL has the narrow beat note line width below 1 Hz, residual mean-square phase error of 0.14 rad(2) and transition time of 100 μs under 10 MHz frequency step. A main innovation of this design is the completely digitalization of the whole controlling circuit in OPLL for diode lasers.

  16. A digital optical phase-locked loop for diode lasers based on field programmable gate array

    NASA Astrophysics Data System (ADS)

    Xu, Zhouxiang; Zhang, Xian; Huang, Kaikai; Lu, Xuanhui

    2012-09-01

    We have designed and implemented a highly digital optical phase-locked loop (OPLL) for diode lasers in atom interferometry. The three parts of controlling circuit in this OPLL, including phase and frequency detector (PFD), loop filter and proportional integral derivative (PID) controller, are implemented in a single field programmable gate array chip. A structure type compatible with the model MAX9382/MCH12140 is chosen for PFD and pipeline and parallelism technology have been adapted in PID controller. Especially, high speed clock and twisted ring counter have been integrated in the most crucial part, the loop filter. This OPLL has the narrow beat note line width below 1 Hz, residual mean-square phase error of 0.14 rad2 and transition time of 100 μs under 10 MHz frequency step. A main innovation of this design is the completely digitalization of the whole controlling circuit in OPLL for diode lasers.

  17. Third generation sfermion decays into Z and W gauge bosons: Full one-loop analysis

    SciTech Connect

    Arhrib, Abdesslam; Benbrik, Rachid

    2005-05-01

    The complete one-loop radiative corrections to third-generation scalar fermions into gauge bosons Z and W{sup {+-}} is considered. We focus on f-tilde{sub 2}{yields}Zf-tilde{sub 1} and f-tilde{sub i}{yields}W{sup {+-}}f-tilde{sub j}{sup '}, f,f{sup '}=t,b. We include SUSY-QCD, QED, and full electroweak corrections. It is found that the electroweak corrections can be of the same order as the SUSY-QCD corrections. The two sets of corrections interfere destructively in some region of parameter space. The full one-loop correction can reach 10% in some supergravity scenario, while in model independent analysis like general the minimal supersymmetric standard model, the one-loop correction can reach 20% for large tan{beta} and large trilinear soft breaking terms A{sub b}.

  18. A digital optical phase-locked loop for diode lasers based on field programmable gate array

    SciTech Connect

    Xu Zhouxiang; Zhang Xian; Huang Kaikai; Lu Xuanhui

    2012-09-15

    We have designed and implemented a highly digital optical phase-locked loop (OPLL) for diode lasers in atom interferometry. The three parts of controlling circuit in this OPLL, including phase and frequency detector (PFD), loop filter and proportional integral derivative (PID) controller, are implemented in a single field programmable gate array chip. A structure type compatible with the model MAX9382/MCH12140 is chosen for PFD and pipeline and parallelism technology have been adapted in PID controller. Especially, high speed clock and twisted ring counter have been integrated in the most crucial part, the loop filter. This OPLL has the narrow beat note line width below 1 Hz, residual mean-square phase error of 0.14 rad{sup 2} and transition time of 100 {mu}s under 10 MHz frequency step. A main innovation of this design is the completely digitalization of the whole controlling circuit in OPLL for diode lasers.

  19. Loop Quantum Gravity and Asymptotically Flat Spaces

    NASA Astrophysics Data System (ADS)

    Arnsdorf, Matthias

    2002-12-01

    Remarkable progress has been made in the field of non-perturbative (loop) quantum gravity in the last decade or so and it is now a rigorously defined kinematical theory (c.f. [5] for a review and references). We are now at the stage where physical applications of loop quantum gravity can be studied and used to provide checks for the consistency of the quantisation programme. Equally, old fundamental problems of canonical quantum gravity such as the problem of time or the interpretation of quantum cosmology need to be reevaluated seriously. These issues can be addressed most profitably in the asymptotically flat sector of quantum gravity. Indeed, it is likely that we should obtain a quantum theory for this special case even if it is not possible to quantise full general relativity. The purpose of this summary is to advertise the extension of loop quantum gravity to this sector that was developed in [1]...

  20. Double reference pulsed phase locked loop

    NASA Technical Reports Server (NTRS)

    Heyman, J. S. (Inventor)

    1986-01-01

    A double reference pulse phase locked loop is described which measures the phase shift between tone burst signals initially derived from the same periodic signal source (voltage controlled oscillator) and delayed by different amounts because of two different paths. A first path is from the transducer to the surface of a sample and back. A second path is from the transducer to the opposite surface and back. A first pulse phase locked loop including a phase detector and a phase shifter forces the tone burst signal delayed by the second path in phase quadrature with the periodic signal source. A second pulse phase locked loop including a second phase detector forces the tone burst signals delayed by the first path into phase quadrature with the phase shifted periodic signal source.

  1. Mass flow in loop type coronal transients

    NASA Technical Reports Server (NTRS)

    Anzer, U.; Poland, A. I.

    1979-01-01

    Coronal transients having characteristics of a well-defined loop structure are examined, particularly with respect to temporal changes in the density and mass per unit length along the loop over periods of several days after the initial eruption. Measurements of mass distributions as a function of time are presented for eight transients, and one particular transient with a fairly simple configuration is investigated in more detail. Theoretical calculations are combined with the masses and densities derived from the observations to obtain estimates of the material flow in the transients; this flow is modeled on the assumption that magnetic forces drive and confine the loop. The flow field is found to be diverging everywhere, indicating that the density decreases in time. It is inferred that the transient legs are approximately in hydrostatic equilibrium and that most of the mass of the transient is lost from the sun during the initial phase.

  2. Closed-loop approach to thermodynamics

    NASA Astrophysics Data System (ADS)

    Goupil, C.; Ouerdane, H.; Herbert, E.; Benenti, G.; D'Angelo, Y.; Lecoeur, Ph.

    2016-09-01

    We present the closed-loop approach to linear nonequilibrium thermodynamics considering a generic heat engine dissipatively connected to two temperature baths. The system is usually quite generally characterized by two parameters: the output power P and the conversion efficiency η , to which we add a third one, the working frequency ω . We establish that a detailed understanding of the effects of the dissipative coupling on the energy conversion process requires only knowing two quantities: the system's feedback factor β and its open-loop gain A0, which product A0β characterizes the interplay between the efficiency, the output power, and the operating rate of the system. By raising the abstract hermodynamic analysis to a higher level, the feedback loop approach provides a versatile and economical, hence fairly efficient, tool for the study of any conversion engine operation for which a feedback factor can be defined.

  3. Counting primary loops in polymer gels

    PubMed Central

    Zhou, Huaxing; Woo, Jiyeon; Cok, Alexandra M.; Wang, Muzhou; Olsen, Bradley D.; Johnson, Jeremiah A.

    2012-01-01

    Much of our fundamental knowledge related to polymer networks is built on an assumption of ideal end-linked network structure. Real networks invariably possess topological imperfections that negatively affect mechanical properties; modifications of classical network theories have been developed to account for these defects. Despite decades of effort, there are no known experimental protocols for precise quantification of even the simplest topological network imperfections: primary loops. Here we present a simple conceptual framework that enables primary loop quantification in polymeric materials. We apply this framework to measure the fraction of primary loop junctions in trifunctional PEG-based hydrogels. We anticipate that the concepts described here will open new avenues of theoretical and experimental research related to polymer network structure. PMID:23132947

  4. Digital tanlock loop architecture with no delay

    NASA Astrophysics Data System (ADS)

    Al-Kharji AL-Ali, Omar; Anani, Nader; Al-Araji, Saleh; Al-Qutayri, Mahmoud; Ponnapalli, Prasad

    2012-02-01

    This article proposes a new architecture for a digital tanlock loop which eliminates the time-delay block. The ? (rad) phase shift relationship between the two channels, which is generated by the delay block in the conventional time-delay digital tanlock loop (TDTL), is preserved using two quadrature sampling signals for the loop channels. The proposed system outperformed the original TDTL architecture, when both systems were tested with frequency shift keying input signal. The new system demonstrated better linearity and acquisition speed as well as improved noise performance compared with the original TDTL architecture. Furthermore, the removal of the time-delay block enables all processing to be digitally performed, which reduces the implementation complexity. Both the original TDTL and the new architecture without the delay block were modelled and simulated using MATLAB/Simulink. Implementation issues, including complexity and relation to simulation of both architectures, are also addressed.

  5. Current loop signal conditioning: Practical applications

    NASA Technical Reports Server (NTRS)

    Anderson, Karl F.

    1995-01-01

    This paper describes a variety of practical application circuits based on the current loop signal conditioning paradigm. Equations defining the circuit response are also provided. The constant current loop is a fundamental signal conditioning circuit concept that can be implemented in a variety of configurations for resistance-based transducers, such as strain gages and resistance temperature detectors. The circuit features signal conditioning outputs which are unaffected by extremely large variations in lead wire resistance, direct current frequency response, and inherent linearity with respect to resistance change. Sensitivity of this circuit is double that of a Wheatstone bridge circuit. Electrical output is zero for resistance change equals zero. The same excitation and output sense wires can serve multiple transducers. More application arrangements are possible with constant current loop signal conditioning than with the Wheatstone bridge.

  6. Examination of the role of the microbial loop in regulating lake nutrient stoichiometry and phytoplankton dynamics

    NASA Astrophysics Data System (ADS)

    Li, Y.; Gal, G.; Makler-Pick, V.; Waite, A. M.; Bruce, L. C.; Hipsey, M. R.

    2014-06-01

    The recycling of organic material through bacteria and microzooplankton to higher trophic levels, known as the "microbial loop", is an important process in aquatic ecosystems. Here the significance of the microbial loop in influencing nutrient supply to phytoplankton has been investigated in Lake Kinneret (Israel) using a coupled hydrodynamic-ecosystem model. The model was designed to simulate the dynamic cycling of carbon, nitrogen and phosphorus through bacteria, phytoplankton and zooplankton functional groups, with each pool having unique C : N : P dynamics. Three microbial loop sub-model configurations were used to isolate mechanisms by which the microbial loop could influence phytoplankton biomass, considering (i) the role of bacterial mineralisation, (ii) the effect of micrograzer excretion, and (iii) bacterial ability to compete for dissolved inorganic nutrients. The nutrient flux pathways between the abiotic pools and biotic groups and the patterns of biomass and nutrient limitation of the different phytoplankton groups were quantified for the different model configurations. Considerable variation in phytoplankton biomass and dissolved organic matter demonstrated the sensitivity of predictions to assumptions about microbial loop operation and the specific mechanisms by which phytoplankton growth was affected. Comparison of the simulations identified that the microbial loop most significantly altered phytoplankton growth by periodically amplifying internal phosphorus limitation due to bacterial competition for phosphate to satisfy their own stoichiometric requirements. Importantly, each configuration led to a unique prediction of the overall community composition, and we conclude that the microbial loop plays an important role in nutrient recycling by regulating not only the quantity, but also the stoichiometry of available N and P that is available to primary producers. The results demonstrate how commonly employed simplifying assumptions about model

  7. [Biological review of completed suicide].

    PubMed

    Otsuka, Ikuo; Sora, Ichiro; Hishimoto, Akitoyo

    2016-06-01

    Family, twin and adoption studies have revealed genetic factors involved in suicide, while the accumulation of stress and mental illnesses are major contributing factors of suicide. Since higher lethality of suicidal behavior is considered to increase familial liability to suicidal behavior, we believe biological research of completed suicide is most important for a better understanding of the pathophysiology in suicide. Dysregulated hypothalamic-pituitary-adrenal axis has gained a special interest in the neurobiology of suicide, mostly because of the findings using a dexamethasone suppression test (DST), in which DST non-suppressors show a nearly 10-fold higher risk of completed suicide than DST suppressors in a depressed cohort. Other data mainly from postmortem brain studies indicate abnormalities of the noradrenergic-locus coeruleus system, serotonergic system, endogenous opioid system, brain-derived neurotrophic factor, inflammatory cytokines and omega-3 fatty acid in completed suicide. However, genetic research of complete suicide is behind other mental problems because it is extremely difficult to obtain tissue samples of completed suicide. Under the difficult situation, we now retain over 800 blood samples of suicide completers thanks to bereaved families' cooperation. We are actively working on the research of suicide, for instance, by performing a GWAS using 500 samples of suicide completers.

  8. Quantum Monte Carlo with directed loops.

    PubMed

    Syljuåsen, Olav F; Sandvik, Anders W

    2002-10-01

    We introduce the concept of directed loops in stochastic series expansion and path-integral quantum Monte Carlo methods. Using the detailed balance rules for directed loops, we show that it is possible to smoothly connect generally applicable simulation schemes (in which it is necessary to include backtracking processes in the loop construction) to more restricted loop algorithms that can be constructed only for a limited range of Hamiltonians (where backtracking can be avoided). The "algorithmic discontinuities" between general and special points (or regions) in parameter space can hence be eliminated. As a specific example, we consider the anisotropic S=1/2 Heisenberg antiferromagnet in an external magnetic field. We show that directed-loop simulations are very efficient for the full range of magnetic fields (zero to the saturation point) and anisotropies. In particular, for weak fields and anisotropies, the autocorrelations are significantly reduced relative to those of previous approaches. The back-tracking probability vanishes continuously as the isotropic Heisenberg point is approached. For the XY model, we show that back tracking can be avoided for all fields extending up to the saturation field. The method is hence particularly efficient in this case. We use directed-loop simulations to study the magnetization process in the two-dimensional Heisenberg model at very low temperatures. For LxL lattices with L up to 64, we utilize the step structure in the magnetization curve to extract gaps between different spin sectors. Finite-size scaling of the gaps gives an accurate estimate of the transverse susceptibility in the thermodynamic limit: chi( perpendicular )=0.0659+/-0.0002.

  9. PREFACE: Loops 11: Non-Perturbative / Background Independent Quantum Gravity

    NASA Astrophysics Data System (ADS)

    Mena Marugán, Guillermo A.; Barbero G, J. Fernando; Garay, Luis J.; Villaseñor, Eduardo J. S.; Olmedo, Javier

    2012-05-01

    Loops 11 The international conference LOOPS'11 took place in Madrid from the 23-28 May 2011. It was hosted by the Instituto de Estructura de la Materia (IEM), which belongs to the Consejo Superior de Investigaciones Cientĺficas (CSIC). Like previous editions of the LOOPS meetings, it dealt with a wealth of state-of-the-art topics on Quantum Gravity, with special emphasis on non-perturbative background-independent approaches to spacetime quantization. The main topics addressed at the conference ranged from the foundations of Quantum Gravity to its phenomenological aspects. They encompassed different approaches to Loop Quantum Gravity and Cosmology, Polymer Quantization, Quantum Field Theory, Black Holes, and discrete approaches such as Dynamical Triangulations, amongst others. In addition, this edition celebrated the 25th anniversary of the introduction of the now well-known Ashtekar variables and the Wednesday morning session was devoted to this silver jubilee. The structure of the conference was designed to reflect the current state and future prospects of research on the different topics mentioned above. Plenary lectures that provided general background and the 'big picture' took place during the mornings, and the more specialised talks were distributed in parallel sessions during the evenings. To be more specific, Monday evening was devoted to Shape Dynamics and Phenomenology Derived from Quantum Gravity in Parallel Session A, and to Covariant Loop Quantum Gravity and Spin foams in Parallel Session B. Tuesday's three Parallel Sessions dealt with Black Hole Physics and Dynamical Triangulations (Session A), the continuation of Monday's session on Covariant Loop Quantum Gravity and Spin foams (Session B) and Foundations of Quantum Gravity (Session C). Finally, Thursday and Friday evenings were devoted to Loop Quantum Cosmology (Session A) and to Hamiltonian Loop Quantum Gravity (Session B). The result of the conference was very satisfactory and enlightening. Not

  10. Coronal Loops: Observations and Modeling of Confined Plasma.

    PubMed

    Reale, Fabio

    Coronal loops are the building blocks of the X-ray bright solar corona. They owe their brightness to the dense confined plasma, and this review focuses on loops mostly as structures confining plasma. After a brief historical overview, the review is divided into two separate but not independent parts: the first illustrates the observational framework, the second reviews the theoretical knowledge. Quiescent loops and their confined plasma are considered and, therefore, topics such as loop oscillations and flaring loops (except for non-solar ones, which provide information on stellar loops) are not specifically addressed here. The observational section discusses the classification, populations, and the morphology of coronal loops, its relationship with the magnetic field, and the loop stranded structure. The section continues with the thermal properties and diagnostics of the loop plasma, according to the classification into hot, warm, and cool loops. Then, temporal analyses of loops and the observations of plasma dynamics, hot and cool flows, and waves are illustrated. In the modeling section, some basics of loop physics are provided, supplying fundamental scaling laws and timescales, a useful tool for consultation. The concept of loop modeling is introduced and models are divided into those treating loops as monolithic and static, and those resolving loops into thin and dynamic strands. More specific discussions address modeling the loop fine structure and the plasma flowing along the loops. Special attention is devoted to the question of loop heating, with separate discussion of wave (AC) and impulsive (DC) heating. Large-scale models including atmosphere boxes and the magnetic field are also discussed. Finally, a brief discussion about stellar coronal loops is followed by highlights and open questions.

  11. An essay on Bergman completeness

    NASA Astrophysics Data System (ADS)

    Chen, Bo-Yong

    2013-10-01

    We give first of all a new criterion for Bergman completeness in terms of the pluricomplex Green function. Among several applications, we prove in particular that every Stein subvariety in a complex manifold admits a Bergman complete Stein neighborhood basis, which improves a theorem of Siu. Secondly, we give for hyperbolic Riemann surfaces a sufficient condition for when the Bergman and Poincaré metrics are quasi-isometric. A consequence is an equivalent characterization of uniformly perfect planar domains in terms of growth rates of the Bergman kernel and metric. Finally, we provide a noncompact Bergman complete pseudoconvex manifold without nonconstant negative plurisubharmonic functions.

  12. Genotype imputation via matrix completion

    PubMed Central

    Chi, Eric C.; Zhou, Hua; Chen, Gary K.; Del Vecchyo, Diego Ortega; Lange, Kenneth

    2013-01-01

    Most current genotype imputation methods are model-based and computationally intensive, taking days to impute one chromosome pair on 1000 people. We describe an efficient genotype imputation method based on matrix completion. Our matrix completion method is implemented in MATLAB and tested on real data from HapMap 3, simulated pedigree data, and simulated low-coverage sequencing data derived from the 1000 Genomes Project. Compared with leading imputation programs, the matrix completion algorithm embodied in our program MENDEL-IMPUTE achieves comparable imputation accuracy while reducing run times significantly. Implementation in a lower-level language such as Fortran or C is apt to further improve computational efficiency. PMID:23233546

  13. Supervisory control of a pilot-scale cooling loop

    SciTech Connect

    Kris Villez; Venkat Venkatasubramanian; Humberto Garcia

    2011-08-01

    We combine a previously developed strategy for Fault Detection and Identification (FDI) with a supervisory controller in closed loop. The combined method is applied to a model of a pilot-scale cooling loop of a nuclear plant, which includes Kalman filters and a model-based predictive controller as part of normal operation. The system has two valves available for flow control meaning that some redundancy is available. The FDI method is based on likelihood ratios for different fault scenarios which in turn are derived from the application of the Kalman filter. A previously introduced extension of the FDI method is used here to enable detection and identification of non-linear faults like stuck valve problems and proper accounting of the time of fault introduction. The supervisory control system is designed so to take different kinds of actions depending on the status of the fault diagnosis task and on the type of identified fault once diagnosis is complete. Some faults, like sensor bias and drift, are parametric in nature and can be adjusted without need for reconfiguration of the regulatory control system. Other faults, like a stuck valve problem, require reconfiguration of the regulatory control system. The whole strategy is demonstrated for several scenarios.

  14. Pure cutting current for loop excision of squamous intraepithelial lesions.

    PubMed

    McLucas, B; McGill, J

    1994-05-01

    Clear margins are critical to the identification of complete excision of premalignant lesions on the cervix. Large loop excision of the transformation zone aids the pathologic evaluation of the excised specimen while it causes minimal thermal damage. Prior studies of loop excision were performed with a cutting current blended with a coagulating waveform to aid hemostasis. Blended current has higher voltage, which may cause tissue to stick to the electrode and produce thermal damage to the cervix. In this series, pure cutting current was used to excise the cervical transformation zone in 20 patients. The depth of thermal damage was studied in 6 patients; the average endocervical zone of damage was 0.47 mm and that of the exocervical zone, 0.43 mm. The base of the cervix could be examined with the colposcope for the presence of glands. None of our procedures was complicated by intraoperative or delayed bleeding. The preoperative injection of a vasoconstrictor into the cervical stroma is thought to aid the surgery by its hemostatic properties.

  15. Quasi-periodic processes in the flare loop generated by sudden temperature enhancements at loop footpoints

    NASA Astrophysics Data System (ADS)

    Karlický, M.; Jelínek, P.

    2016-05-01

    Aims: During the impulsive flare phase, the plasma at the flare loop footpoints is rapidly heated by particle beams. In the present paper, we study processes that occur after this sudden heating in a two-dimensional magnetic loop. Methods: We adopt a 2D magnetohydrodynamic (MHD) model, in which we solve a full set of the ideal time-dependent MHD equations by means of the FLASH code, using the adaptive mesh refinement (AMR) method. Periods in the processes are estimated by the wavelet analysis technique. Results: We consider a model of the solar atmosphere with a symmetric magnetic loop. The length of this loop in the corona is approximately 21.5 Mm. At both loop footpoints, at the transition region, we initiate the Gaussian temperature (pressure) perturbation with the maximum temperature 14, 7, or 3.5 times higher than the unperturbed temperature. In the corona, the perturbations produce supersonic blast shocks with the Mach number of about 1.1, but well below Alfvén velocities. We consider cases with the same perturbations at both footpoints (symmetric case) and one with different perturbations (asymmetric case). In the symmetric case, the shocks move along both loop legs upwards to the top of the loop, where they interact and form a transient compressed region. Then they continue in their motion to the transition region at the opposite side of the loop, where they are reflected upwards, and so on. At the top of the loop, the shock appears periodically with the period of about 170 s. In the loop legs during this period, a double peak of the plasma parameters, which is connected with two arrivals of shocks, is detected: firstly, when the shock moves up and then when the shock, propagating from the opposite loop leg, moves down. Increasing the distance of the detection point in the loop leg from the top of the loop, the time interval between these shock arrivals increases. Thus, at these detection points, the processes with shorter periods can be detected. After

  16. MHD Modelling of Coronal Loops: Injection of High-Speed Chromospheric Flows

    NASA Technical Reports Server (NTRS)

    Petralia, A.; Reale, F.; Orlando, S.; Klimchuk, J. A.

    2014-01-01

    Context. Observations reveal a correspondence between chromospheric type II spicules and bright upward-moving fronts in the corona observed in the extreme-ultraviolet (EUV) band. However, theoretical considerations suggest that these flows are probably not the main source of heating in coronal magnetic loops. Aims. We investigate the propagation of high-speed chromospheric flows into coronal magnetic flux tubes and the possible production of emission in the EUV band. Methods. We simulated the propagation of a dense 104 K chromospheric jet upward along a coronal loop by means of a 2D cylindrical MHD model that includes gravity, radiative losses, thermal conduction, and magnetic induction. The jet propagates in a complete atmosphere including the chromosphere and a tenuous cool (approximately 0.8 MK) corona, linked through a steep transition region. In our reference model, the jet initial speed is 70 km per second, its initial density is 10(exp 11) per cubic centimeter, and the ambient uniform magnetic field is 10 G. We also explored other values of jet speed and density in 1D and different magnetic field values in 2D, as well as the jet propagation in a hotter (approximately 1.5 MK) background loop. Results. While the initial speed of the jet does not allow it to reach the loop apex, a hot shock-front develops ahead of it and travels to the other extreme of the loop. The shock front compresses the coronal plasma and heats it to about 10(exp 6) K. As a result, a bright moving front becomes visible in the 171 Angstrom channel of the SDO/AIA mission. This result generally applies to all the other explored cases, except for the propagation in the hotter loop. Conclusions. For a cool, low-density initial coronal loop, the post-shock plasma ahead of upward chromospheric flows might explain at least part of the observed correspondence between type II spicules and EUV emission excess.

  17. Identification of residues in a hydrophilic loop of the Papaver rhoeas S protein that play a crucial role in recognition of incompatible pollen.

    PubMed Central

    Kakeda, K; Jordan, N D; Conner, A; Ride, J P; Franklin-Tong, V E; Franklin, F C

    1998-01-01

    The self-incompatibility response involves S allele-specific recognition between stigmatic S proteins and incompatible pollen. This response results in pollen inhibition. Defining the amino acid residues within the stigmatic S proteins that participate in S allele-specific inhibition of incompatible pollen is essential for the elucidation of the molecular basis of the self-incompatibility response. We have constructed mutant derivatives of the S1 protein from Papaver rhoeas by using site-directed mutagenesis and have tested their biological activity. This has enabled us to identify amino acid residues in the stigmatic S proteins of P. rhoeas that are required for S-specific inhibition of incompatible pollen. We report here the identification of several amino acid residues in the predicted hydrophilic loop 6 of the P. rhoeas stigmatic S1 protein that are involved in the inhibition of S1 pollen. Mutation of the only hypervariable amino acid, which is situated in this loop, resulted in the complete loss of ability of the S protein to inhibit S1 pollen. This clearly demonstrates that this residue plays a crucial role in pollen recognition and may also participate in defining allelic specificity. We have also established the importance of highly conserved amino acids adjacent to this hypervariable site. Our studies demonstrate that both variable and conserved amino acids in the region of the S protein corresponding to surface loop 6 are key elements that play a role in the recognition and inhibition of incompatible pollen in the pollen-pistil self-incompatibility reaction. PMID:9761798

  18. Loop Optimization for Tensor Network Renormalization

    NASA Astrophysics Data System (ADS)

    Yang, Shuo; Gu, Zheng-Cheng; Wen, Xiao-Gang

    2017-03-01

    We introduce a tensor renormalization group scheme for coarse graining a two-dimensional tensor network that can be successfully applied to both classical and quantum systems on and off criticality. The key innovation in our scheme is to deform a 2D tensor network into small loops and then optimize the tensors on each loop. In this way, we remove short-range entanglement at each iteration step and significantly improve the accuracy and stability of the renormalization flow. We demonstrate our algorithm in the classical Ising model and a frustrated 2D quantum model.

  19. Temperature Oscillations in Loop Heat Pipe Operation

    NASA Technical Reports Server (NTRS)

    Ku, Jentung; Ottenstein, Laura; Kobel, Mark; Rogers, Paul; Kaya, Tarik; Paquin, Krista C. (Technical Monitor)

    2000-01-01

    Loop heat pipes (LHPs) are versatile two-phase heat transfer devices that have gained increasing acceptance for space and terrestrial applications. The operating temperature of an LHP is a function of its operating conditions. The LHP usually reaches a steady operating temperature for a given heat load and sink temperature. The operating temperature will change when the heat load and/or the sink temperature changes, but eventually reaches another steady state in most cases. Under certain conditions, however, the loop operating temperature never really reaches a true steady state, but instead becomes oscillatory. This paper discusses the temperature oscillation phenomenon using test data from a miniature LHP.

  20. Anomaly freedom in perturbative loop quantum gravity

    SciTech Connect

    Bojowald, Martin; Hossain, Golam Mortuza; Kagan, Mikhail; Shankaranarayanan, S.

    2008-09-15

    A fully consistent linear perturbation theory for cosmology is derived in the presence of quantum corrections as they are suggested by properties of inverse volume operators in loop quantum gravity. The underlying constraints present a consistent deformation of the classical system, which shows that the discreteness in loop quantum gravity can be implemented in effective equations without spoiling space-time covariance. Nevertheless, nontrivial quantum corrections do arise in the constraint algebra. Since correction terms must appear in tightly controlled forms to avoid anomalies, detailed insights for the correct implementation of constraint operators can be gained. The procedures of this article thus provide a clear link between fundamental quantum gravity and phenomenology.

  1. Three loop cusp anomalous dimension in QCD.

    PubMed

    Grozin, Andrey; Henn, Johannes M; Korchemsky, Gregory P; Marquard, Peter

    2015-02-13

    We present the full analytic result for the three loop angle-dependent cusp anomalous dimension in QCD. With this result, infrared divergences of planar scattering processes with massive particles can be predicted to that order. Moreover, we define a closely related quantity in terms of an effective coupling defined by the lightlike cusp anomalous dimension. We find evidence that this quantity is universal for any gauge theory and use this observation to predict the nonplanar n(f)-dependent terms of the four loop cusp anomalous dimension.

  2. LCL Current Control Loop Stability Design

    NASA Astrophysics Data System (ADS)

    Delepaut, Christophe; Kuremyr, Tobias; Martin, Manuel; Tonicello, Ferdinando

    2014-08-01

    Latching Current Limiters include a control loop meant at limiting the current in case of downstream failure. Such current control loop consists typically of a simple proportional feedback gain from a current measurement shunt resistance and may result in very limited phase margin for specified operating conditions. The present paper investigates the combination of a proportional and derivative feedback to mitigate the lack of stability margin, providing a comprehensive overview on designing Latching Current Limiters for stability. For illustration purpose, a LCL based on radiation hardened ITAR free components is considered. A breadboard has been manufactured and the reported phase margin measurements demonstrate performances in line with the analytic results.

  3. Similarity Metrics for Closed Loop Dynamic Systems

    NASA Technical Reports Server (NTRS)

    Whorton, Mark S.; Yang, Lee C.; Bedrossian, Naz; Hall, Robert A.

    2008-01-01

    To what extent and in what ways can two closed-loop dynamic systems be said to be "similar?" This question arises in a wide range of dynamic systems modeling and control system design applications. For example, bounds on error models are fundamental to the controller optimization with modern control design methods. Metrics such as the structured singular value are direct measures of the degree to which properties such as stability or performance are maintained in the presence of specified uncertainties or variations in the plant model. Similarly, controls-related areas such as system identification, model reduction, and experimental model validation employ measures of similarity between multiple realizations of a dynamic system. Each area has its tools and approaches, with each tool more or less suited for one application or the other. Similarity in the context of closed-loop model validation via flight test is subtly different from error measures in the typical controls oriented application. Whereas similarity in a robust control context relates to plant variation and the attendant affect on stability and performance, in this context similarity metrics are sought that assess the relevance of a dynamic system test for the purpose of validating the stability and performance of a "similar" dynamic system. Similarity in the context of system identification is much more relevant than are robust control analogies in that errors between one dynamic system (the test article) and another (the nominal "design" model) are sought for the purpose of bounding the validity of a model for control design and analysis. Yet system identification typically involves open-loop plant models which are independent of the control system (with the exception of limited developments in closed-loop system identification which is nonetheless focused on obtaining open-loop plant models from closed-loop data). Moreover the objectives of system identification are not the same as a flight test and

  4. A double-loop tracking system.

    NASA Technical Reports Server (NTRS)

    Yuen, J. H.

    1972-01-01

    A nonlinear analysis which can be used to assess certain statistical characteristics of double-loop tracking systems is presented. It takes into account the mutual coupling effects of the loops in the system. Two approaches are taken to obtain steady-state probability density functions (pdf's) of the system phase errors. From these pdf's, important system performance statistics, e.g., the phase-error variances, can be calculated, thus illustrating the application and usefulness of the analysis. The analysis is applied to a satellite transponder as an example.

  5. Silicon photonic dynamic optical channel leveler with external feedback loop.

    PubMed

    Doylend, J K; Jessop, P E; Knights, A P

    2010-06-21

    We demonstrate a dynamic optical channel leveler composed of a variable optical attenuator (VOA) integrated monolithically with a defect-mediated photodiode in a silicon photonic waveguide device. An external feedback loop mimics an analog circuit such that the photodiode directly controls the VOA to provide blind channel leveling within +/-1 dB across a 7-10 dB dynamic range for wavelengths from 1530 nm to 1570 nm. The device consumes approximately 50 mW electrical power and occupies a 6 mm x 0.1 mm footprint per channel. Dynamic leveling is accomplished without tapping optical power from the output path to the photodiode and thus the loss penalty is minimized.

  6. SWI/SNF- and RSC-catalyzed nucleosome mobilization requires internal DNA loop translocation within nucleosomes.

    PubMed

    Liu, Ning; Peterson, Craig L; Hayes, Jeffrey J

    2011-10-01

    The multisubunit SWI/SNF and RSC complexes utilize energy derived from ATP hydrolysis to mobilize nucleosomes and render the DNA accessible for various nuclear processes. Here we test the idea that remodeling involves intermediates with mobile DNA bulges or loops within the nucleosome by cross-linking the H2A N- or C-terminal tails together to generate protein "loops" that constrict separation of the DNA from the histone surface. Analyses indicate that this intranucleosomal cross-linking causes little or no change in remodeling-dependent exposure of DNA sequences within the nucleosome to restriction enzymes. However, cross-linking inhibits nucleosome mobilization and blocks complete movement of nucleosomes to extreme end positions on the DNA fragments. These results are consistent with evidence that nucleosome remodeling involves intermediates with DNA loops on the nucleosome surface but indicate that such loops do not freely diffuse about the surface of the histone octamer. We propose a threading model for movement of DNA loops around the perimeter of the nucleosome core.

  7. JWST Primary Mirror Installation Complete

    NASA Video Gallery

    Completing the assembly of the primary mirror, which took place at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, is a significant milestone and the culmination of over a decade of desi...

  8. Is complete seizure control imperative?

    PubMed

    Andermann, Frederick

    2002-01-01

    Is complete control imperative? The answer depends on whether complete control is indeed possible, on the possibility of achieving modifications of lifestyle, and on the type of epilepsy, with particular reference to the presence of progressive dysfunction. This may be seen in patients with temporal lobe or other forms of focal epilepsy, in the epileptic encephalopathies such as West and Lennox Gastaut Syndromes and even in some patients with idiopathic generalized epilepsy. Progressive memory changes and global cognitive problems are examples. Progressive language deterioration, secondary epileptogenesis and phenomena analogous to kindling are also important issues. How long treatment should be continued depends on many factors, not least the preference of the patient and of the family. Weighing the benefits of complete control versus the side effects and risks of medication or surgery is crucial. There are obvious benefits to complete control; it is imperative if these benefits are greater than the cost.

  9. Looping probabilities of elastic chains: a path integral approach.

    PubMed

    Cotta-Ramusino, Ludovica; Maddocks, John H

    2010-11-01

    We consider an elastic chain at thermodynamic equilibrium with a heat bath, and derive an approximation to the probability density function, or pdf, governing the relative location and orientation of the two ends of the chain. Our motivation is to exploit continuum mechanics models for the computation of DNA looping probabilities, but here we focus on explaining the novel analytical aspects in the derivation of our approximation formula. Accordingly, and for simplicity, the current presentation is limited to the illustrative case of planar configurations. A path integral formalism is adopted, and, in the standard way, the first approximation to the looping pdf is obtained from a minimal energy configuration satisfying prescribed end conditions. Then we compute an additional factor in the pdf which encompasses the contributions of quadratic fluctuations about the minimum energy configuration along with a simultaneous evaluation of the partition function. The original aspects of our analysis are twofold. First, the quadratic Lagrangian describing the fluctuations has cross-terms that are linear in first derivatives. This, seemingly small, deviation from the structure of standard path integral examples complicates the necessary analysis significantly. Nevertheless, after a nonlinear change of variable of Riccati type, we show that the correction factor to the pdf can still be evaluated in terms of the solution to an initial value problem for the linear system of Jacobi ordinary differential equations associated with the second variation. The second novel aspect of our analysis is that we show that the Hamiltonian form of these linear Jacobi equations still provides the appropriate correction term in the inextensible, unshearable limit that is commonly adopted in polymer physics models of, e.g. DNA. Prior analyses of the inextensible case have had to introduce nonlinear and nonlocal integral constraints to express conditions on the relative displacement of the end

  10. Closed loop supply chain network design with fuzzy tactical decisions

    NASA Astrophysics Data System (ADS)

    Sherafati, Mahtab; Bashiri, Mahdi

    2016-01-01

    One of the most strategic and the most significant decisions in supply chain management is reconfiguration of the structure and design of the supply chain network. In this paper, a closed loop supply chain network design model is presented to select the best tactical and strategic decision levels simultaneously considering the appropriate transportation mode in activated links. The strategic decisions are made for a long term; thus, it is more satisfactory and more appropriate when the decision variables are considered uncertain and fuzzy, because it is more flexible and near to the real world. This paper is the first research which considers fuzzy decision variables in the supply chain network design model. Moreover, in this study a new fuzzy optimization approach is proposed to solve a supply chain network design problem with fuzzy tactical decision variables. Finally, the proposed approach and model are verified using several numerical examples. The comparison of the results with other existing approaches confirms efficiency of the proposed approach. Moreover the results confirms that by considering the vagueness of tactical decisions some properties of the supply chain network will be improved.

  11. Modulation of DNA loop lifetimes by the free energy of loop formation

    PubMed Central

    Chen, Yi-Ju; Johnson, Stephanie; Mulligan, Peter; Spakowitz, Andrew J.; Phillips, Rob

    2014-01-01

    Storage and retrieval of the genetic information in cells is a dynamic process that requires the DNA to undergo dramatic structural rearrangements. DNA looping is a prominent example of such a structural rearrangement that is essential for transcriptional regulation in both prokaryotes and eukaryotes, and the speed of such regulations affects the fitness of individuals. Here, we examine the in vitro looping dynamics of the classic Lac repressor gene-regulatory motif. We show that both loop association and loop dissociation at the DNA-repressor junctions depend on the elastic deformation of the DNA and protein, and that both looping and unlooping rates approximately scale with the looping J factor, which reflects the system’s deformation free energy. We explain this observation by transition state theory and model the DNA–protein complex as an effective worm-like chain with twist. We introduce a finite protein–DNA binding interaction length, in competition with the characteristic DNA deformation length scale, as the physical origin of the previously unidentified loop dissociation dynamics observed here, and discuss the robustness of this behavior to perturbations in several polymer parameters. PMID:25411314

  12. Radiation Enhanced Absorption of Frank Loops by Nanovoids in Cu

    NASA Astrophysics Data System (ADS)

    Chen, Y.; Zhang, X.; Wang, J.

    2016-01-01

    Neutron and heavy ion irradiations generally induce voids in metallic materials, and continuous radiations typically result in void swelling and mechanical failure of the irradiated materials. Recent experiments showed that nanovoids in nanotwinned copper could act as sinks for radiation-induced Frank loops, significantly mitigating radiation damage. In this paper, we report on structural evolution of Frank loops under cascades and address the role of nanovoids in absorbing Frank loops in detail by using molecular dynamics simulations. Results show that a stand-alone Frank loop is stable under cascades. When Frank loops are adjacent to nanovoids, the diffusion of a group of atoms from the loop into nanovoids is accomplished via the formation and propagation of dislocation loops. The loop-nanovoid interactions result in the shrinkage of the nanovoids and the Frank loops.

  13. Radiation Enhanced Absorption of Frank Loops by Nanovoids in Cu

    SciTech Connect

    Chen, Youxing; Zhang, Xinghang; Wang, Jian

    2016-11-01

    Neutron and heavy ion irradiation generally induces voids in metallic materials, and continuous radiations typically result in void swelling and mechanical failure of the irradiated materials. Recent experiments showed that nanovoids in nanotwinned copper could act as sinks for radiation-induced Frank loops, significantly mitigating radiation damage [Y. Chen et al., Nat. Commun. 6:7036 (2015)]. In this paper, we report on structural evolution of Frank loops under cascades and address the role of nanovoids in absorbing Frank loops in detail by using molecular dynamics simulations. Results show that a stand-alone Frank loop is stable under cascades. When Frank loops are adjacent to nanovoids, the diffusion of a group of atoms from the loop into nanovoids is accomplished via the formation and propagation of dislocation loops. The loop-nanovoid interactions result in the shrinkage of the nanovoids and the Frank loops.

  14. Radiation Enhanced Absorption of Frank Loops by Nanovoids in Cu

    DOE PAGES

    Chen, Youxing; Zhang, Xinghang; Wang, Jian

    2016-11-01

    Neutron and heavy ion irradiation generally induces voids in metallic materials, and continuous radiations typically result in void swelling and mechanical failure of the irradiated materials. Recent experiments showed that nanovoids in nanotwinned copper could act as sinks for radiation-induced Frank loops, significantly mitigating radiation damage [Y. Chen et al., Nat. Commun. 6:7036 (2015)]. In this paper, we report on structural evolution of Frank loops under cascades and address the role of nanovoids in absorbing Frank loops in detail by using molecular dynamics simulations. Results show that a stand-alone Frank loop is stable under cascades. When Frank loops are adjacentmore » to nanovoids, the diffusion of a group of atoms from the loop into nanovoids is accomplished via the formation and propagation of dislocation loops. The loop-nanovoid interactions result in the shrinkage of the nanovoids and the Frank loops.« less

  15. Fast half-loop maneuvers for a high alpha fighter aircraft using a singular perturbation feedback control law

    NASA Technical Reports Server (NTRS)

    Garrett, Frederick E., Jr.; Stalford, Harold L.

    1989-01-01

    Singular perturbation analysis is used to derive an outer layer feedback control law for a high alpha fighter aircraft to perform the half-loop maneuver. Pitch rate and angle of attack are treated as fast variables in the derivation. Bang-bang controls are derived to transfer the aircraft state from trim to the outer layer and from the outer layer to specified final half-loop values. The pitch rate is treated as a varibale faster than the angle of attack in the transfer of the state to and from the outer layer. A simulation of the derived control law is conducted at Mach 0.6 and 15,000 feet altitude. The half-loop was performed in 13.12 seconds. It is compared with a NASA pilot simulated half-loop maneuver which took 22.42 seconds for the same initial conditions.

  16. Deconfined Quantum Criticality, Scaling Violations, and Classical Loop Models

    NASA Astrophysics Data System (ADS)

    Nahum, Adam; Chalker, J. T.; Serna, P.; Ortuño, M.; Somoza, A. M.

    2015-10-01

    Numerical studies of the transition between Néel and valence bond solid phases in two-dimensional quantum antiferromagnets give strong evidence for the remarkable scenario of deconfined criticality, but display strong violations of finite-size scaling that are not yet understood. We show how to realize the universal physics of the Néel-valence-bond-solid (VBS) transition in a three-dimensional classical loop model (this model includes the subtle interference effect that suppresses hedgehog defects in the Néel order parameter). We use the loop model for simulations of unprecedentedly large systems (up to linear size L =512 ). Our results are compatible with a continuous transition at which both Néel and VBS order parameters are critical, and we do not see conventional signs of first-order behavior. However, we show that the scaling violations are stronger than previously realized and are incompatible with conventional finite-size scaling, even if allowance is made for a weakly or marginally irrelevant scaling variable. In particular, different approaches to determining the anomalous dimensions ηVBS and ηN é el yield very different results. The assumption of conventional finite-size scaling leads to estimates that drift to negative values at large sizes, in violation of the unitarity bounds. In contrast, the decay with distance of critical correlators on scales much smaller than system size is consistent with large positive anomalous dimensions. Barring an unexpected reversal in behavior at still larger sizes, this implies that the transition, if continuous, must show unconventional finite-size scaling, for example, from an additional dangerously irrelevant scaling variable. Another possibility is an anomalously weak first-order transition. By analyzing the renormalization group flows for the noncompact CP n -1 field theory (the n -component Abelian Higgs model) between two and four dimensions, we give the simplest scenario by which an anomalously weak first

  17. Closed loop computer control for an automatic transmission

    DOEpatents

    Patil, Prabhakar B.

    1989-01-01

    In an automotive vehicle having an automatic transmission that driveably connects a power source to the driving wheels, a method to control the application of hydraulic pressure to a clutch, whose engagement produces an upshift and whose disengagement produces a downshift, the speed of the power source, and the output torque of the transmission. The transmission output shaft torque and the power source speed are the controlled variables. The commanded power source torque and commanded hydraulic pressure supplied to the clutch are the control variables. A mathematical model is formulated that describes the kinematics and dynamics of the powertrain before, during and after a gear shift. The model represents the operating characteristics of each component and the structural arrangement of the components within the transmission being controlled. Next, a close loop feedback control is developed to determine the proper control law or compensation strategy to achieve an acceptably smooth gear ratio change, one in which the output torque disturbance is kept to a minimum and the duration of the shift is minimized. Then a computer algorithm simulating the shift dynamics employing the mathematical model is used to study the effects of changes in the values of the parameters established from a closed loop control of the clutch hydraulic and the power source torque on the shift quality. This computer simulation is used also to establish possible shift control strategies. The shift strategies determined from the prior step are reduced to an algorithm executed by a computer to control the operation of the power source and the transmission.

  18. Closing the loop of the soil water retention curve

    USGS Publications Warehouse

    Lu, Ning; Alsherif, N; Wayllace, Alexandra; Godt, Jonathan W.

    2015-01-01

    The authors, to their knowledge for the first time, produced two complete principal soil water retention curves (SWRCs) under both positive and negative matric suction regimes. An innovative testing technique combining the transient water release and imbibition method (TRIM) and constant flow method (CFM) was used to identify the principal paths of SWRC in the positive pore-water pressure regime under unsaturated conditions. A negative matric suction of 9.8 kPa is needed to reach full saturation or close the loop of the SWRC for a silty soil. This work pushes the understanding of the interaction of soil and water into new territory by quantifying the boundaries of the SWRC over the entire suction domain, including both wetting and drying conditions that are relevant to field conditions such as slope wetting under heavy rainfall or rapid groundwater table rise in earthen dams or levees.

  19. Research on starlight hardware-in-the-loop simulator

    NASA Astrophysics Data System (ADS)

    Zhang, Ying; Gao, Yang; Qu, Huiyang; Liu, Dongfang; Du, Huijie; Lei, Jie

    2016-10-01

    The starlight navigation is considered to be one of the most important methods for spacecraft navigation. Starlight simulation system is a high-precision system with large fields of view, designed to test the starlight navigation sensor performance on the ground. A complete hardware-in-the-loop simulation of the system has been built. The starlight simulator is made up of light source, light source controller, light filter, LCD, collimator and control computer. LCD is the key display component of the system, and is installed at the focal point of the collimator. For the LCD cannot emit light itself, so light source and light source power controller is specially designed for the brightness demanded by the LCD. Light filter is designed for the dark background which is also needed in the simulation.

  20. When matching matters: Loop effects in Higgs effective theory

    NASA Astrophysics Data System (ADS)

    Freitas, Ayres; López-Val, David; Plehn, Tilman

    2016-11-01

    Effective Lagrangians are a useful tool for a data-driven approach to physics beyond the Standard Model at the LHC. However, for the new physics scales accessible at the LHC, the effective operator expansion is only relatively slowly converging at best. For tree-level processes, it has been found that the agreement between the effective Lagrangian and a range of UV-complete models depends sensitively on the appropriate definition of the matching. We extend this analysis to the one-loop level, which is relevant for electroweak precision data and Higgs decay to photons. We show that near the scale of electroweak symmetry breaking the validity of the effective theory description can be systematically improved through an appropriate matching procedure. In particular, we find a significant increase in accuracy when including suitable terms suppressed by the Higgs vacuum expectation value in the matching.

  1. Advanced Hybrid Spacesuit Concept Featuring Integrated Open Loop and Closed Loop Ventilation Systems

    NASA Technical Reports Server (NTRS)

    Daniel, Brian A.; Fitzpatrick, Garret R.; Gohmert, Dustin M.; Ybarra, Rick M.; Dub, Mark O.

    2013-01-01

    A document discusses the design and prototype of an advanced spacesuit concept that integrates the capability to function seamlessly with multiple ventilation system approaches. Traditionally, spacesuits are designed to operate both dependently and independently of a host vehicle environment control and life support system (ECLSS). Spacesuits that operate independent of vehicle-provided ECLSS services must do so with equipment selfcontained within or on the spacesuit. Suits that are dependent on vehicle-provided consumables must remain physically connected to and integrated with the vehicle to operate properly. This innovation is the design and prototype of a hybrid spacesuit approach that configures the spacesuit to seamlessly interface and integrate with either type of vehicular systems, while still maintaining the ability to function completely independent of the vehicle. An existing Advanced Crew Escape Suit (ACES) was utilized as the platform from which to develop the innovation. The ACES was retrofitted with selected components and one-off items to achieve the objective. The ventilation system concept was developed and prototyped/retrofitted to an existing ACES. Components were selected to provide suit connectors, hoses/umbilicals, internal breathing system ducting/ conduits, etc. The concept utilizes a lowpressure- drop, high-flow ventilation system that serves as a conduit from the vehicle supply into the suit, up through a neck seal, into the breathing helmet cavity, back down through the neck seal, out of the suit, and returned to the vehicle. The concept also utilizes a modified demand-based breathing system configured to function seamlessly with the low-pressure-drop closed-loop ventilation system.

  2. Extrasensitive phase-locked-loop circuit

    NASA Technical Reports Server (NTRS)

    Nyiri, E. J.

    1977-01-01

    Modified phase-locked loop (PLL) generates clock from incoming data signal. To minimize effects of threshold phase-detector gain variations, the PLL uses a dither oscillator, a dither band-pass filter, and correlator instead of coherent amplitude detector.

  3. BIOREACTOR DESIGN - OUTER LOOP LANDFILL, LOUISVILLE, KY

    EPA Science Inventory

    Bioreactor field demonstration projects are underway at the Outer Loop Landfill in Louisville, KY, USA. The research effort is a cooperative research effort between US EPA and Waste Management Inc. Two primary kinds of municipal waste bioreactors are under study at this site. ...

  4. Parachute Line Hook Includes Integral Loop Expander

    NASA Technical Reports Server (NTRS)

    Bayless, G. B.

    1983-01-01

    Parachute packing simplified with modified line hook. One person packs parachutes for test recovery vehicles faster than previously two-person team. New line hook includes expander that opens up two locking loops so parachute lines are pulled through them. Parachutes are packed at high pressure to be compressed into limited space available in test vehicles.

  5. Looping for Long-Term Success

    ERIC Educational Resources Information Center

    Coash, Vicki; Watkins, Karen

    2005-01-01

    At Santa Maria Middle School in southwest Phoenix, Arizona, teachers have decided to maintain their relationships with their students by looping through sixth, seventh, and eighth grades. Here, they describe the results of the first three years of the program, discussing the development of their team's priorities and the strategies they embraced…

  6. Can Thermal Nonequilibrium Explain Coronal Loops?

    NASA Technical Reports Server (NTRS)

    Klimchuk, James A.; Karpen, Judy T.; Antiochos, Spiro K.

    2010-01-01

    Any successful model of coronal loops must explain a number of observed properties. For warm (approx. 1 MK) loops, these include: 1. excess density, 2. flat temperature profile, 3. super-hydrostatic scale height, 4. unstructured intensity profile, and 5. 1000-5000 s lifetime. We examine whether thermal nonequilibrium can reproduce the observations by performing hydrodynamic simulations based on steady coronal heating that decreases exponentially with height. We consider both monolithic and multi-stranded loops. The simulations successfully reproduce certain aspects of the observations, including the excess density, but each of them fails in at least one critical way. -Xonolithic models have far too much intensity structure, while multi-strand models are either too structured or too long-lived. Storms of nanoflares remain the only viable explanation for warm loops that has been proposed so far. Our results appear to rule out the widespread existence of heating that is both highly concentrated low in the corona and steady or quasi-steady (slowly varying or impulsive with a rapid cadence). Active regions would have a very different appearance if the dominant heating mechanism had these properties. Thermal nonequilibrium may nonetheless play an important role in prominences and catastrophic cooling e(veen.gts..,coronal rain) that occupy a small fraction of the coronal volume. However, apparent inconsistencies between the models and observations of cooling events have yet to be understood.

  7. Energy Release in Driven Twisted Coronal Loops

    NASA Astrophysics Data System (ADS)

    Bareford, M. R.; Gordovskyy, M.; Browning, P. K.; Hood, A. W.

    2016-01-01

    We investigate magnetic reconnection in twisted magnetic fluxtubes, representing coronal loops. The main goal is to establish the influence of the field geometry and various thermodynamic effects on the stability of twisted fluxtubes and on the size and distribution of heated regions. In particular, we aim to investigate to what extent the earlier idealised models, based on the initially cylindrically symmetric fluxtubes, are different from more realistic models, including the large-scale curvature, atmospheric stratification, thermal conduction and other effects. In addition, we compare the roles of Ohmic heating and shock heating in energy conversion during magnetic reconnection in twisted loops. The models with straight fluxtubes show similar distribution of heated plasma during the reconnection: it initially forms a helical shape, which subsequently becomes very fragmented. The heating in these models is rather uniformly distributed along fluxtubes. At the same time, the hot plasma regions in curved loops are asymmetric and concentrated close to the loop tops. Large-scale curvature has a destabilising influence: less twist is needed for instability. Footpoint convergence normally delays the instability slightly, although in some cases, converging fluxtubes can be less stable. Finally, introducing a stratified atmosphere gives rise to decaying wave propagation, which has a destabilising effect.

  8. Warm inflationary model in loop quantum cosmology

    SciTech Connect

    Herrera, Ramon

    2010-06-15

    A warm inflationary universe model in loop quantum cosmology is studied. In general we discuss the condition of inflation in this framework. By using a chaotic potential, V({phi}){proportional_to}{phi}{sup 2}, we develop a model where the dissipation coefficient {Gamma}={Gamma}{sub 0}=constant. We use recent astronomical observations for constraining the parameters appearing in our model.

  9. Interstitial loop transformations in FeCr

    SciTech Connect

    Béland, Laurent Karim; Osetsky, Yuri N.; Stoller, Roger E.; Xu, Haixuan

    2015-03-27

    Here, we improve the Self-Evolving Atomistic Kinetic Monte Carlo (SEAKMC) algorithm by integrating the Activation Relaxation Technique nouveau (ARTn), a powerful open-ended saddle-point search method, into the algorithm. We use it to investigate the reaction of 37-interstitial 1/2[1 1 1] and 1/2[View the MathML source] loops in FeCr at 10 at.% Cr. They transform into 1/2[1 1 1], 1/2[View the MathML source], [1 0 0] and [0 1 0] 74-interstitial clusters with an overall barrier of 0.85 eV. We find that Cr decoration locally inhibits the rotation of crowdions, which dictates the final loop orientation. Moreover, the final loop orientation depends on the details of the Cr decoration. Generally, a region of a given orientation is favored if Cr near its interface with a region of another orientation is able to inhibit reorientation at this interface more than the Cr present at the other interfaces. Also, we find that substitutional Cr atoms can diffuse from energetically unfavorable to energetically favorable sites within the interlocked 37-interstitial loops conformation with barriers of less than 0.35 eV.

  10. Interstitial loop transformations in FeCr

    DOE PAGES

    Béland, Laurent Karim; Osetsky, Yuri N.; Stoller, Roger E.; ...

    2015-03-27

    Here, we improve the Self-Evolving Atomistic Kinetic Monte Carlo (SEAKMC) algorithm by integrating the Activation Relaxation Technique nouveau (ARTn), a powerful open-ended saddle-point search method, into the algorithm. We use it to investigate the reaction of 37-interstitial 1/2[1 1 1] and 1/2[View the MathML source] loops in FeCr at 10 at.% Cr. They transform into 1/2[1 1 1], 1/2[View the MathML source], [1 0 0] and [0 1 0] 74-interstitial clusters with an overall barrier of 0.85 eV. We find that Cr decoration locally inhibits the rotation of crowdions, which dictates the final loop orientation. Moreover, the final loop orientationmore » depends on the details of the Cr decoration. Generally, a region of a given orientation is favored if Cr near its interface with a region of another orientation is able to inhibit reorientation at this interface more than the Cr present at the other interfaces. Also, we find that substitutional Cr atoms can diffuse from energetically unfavorable to energetically favorable sites within the interlocked 37-interstitial loops conformation with barriers of less than 0.35 eV.« less

  11. Fun with higher-loop Feynman diagrams

    NASA Astrophysics Data System (ADS)

    Luthe, Thomas; Schröder, York

    2016-10-01

    We review recent progress that we have achieved in evaluating the class of fully massive vacuum integrals at five loops. After discussing topics that arise in classification, evaluation and algorithmic codification of this specific set of Feynman integrals, we present some selected new results for their expansions around 4 — 2ε dimensions.

  12. Particle scattering in loop quantum gravity.

    PubMed

    Modesto, Leonardo; Rovelli, Carlo

    2005-11-04

    We devise a technique for defining and computing -point functions in the context of a background-independent gravitational quantum field theory. We construct a tentative implementation of this technique in a perturbatively finite model defined using spin foam techniques in the context of loop quantum gravity.

  13. Selective purge for hydrogenation reactor recycle loop

    DOEpatents

    Baker, Richard W.; Lokhandwala, Kaaeid A.

    2001-01-01

    Processes and apparatus for providing improved contaminant removal and hydrogen recovery in hydrogenation reactors, particularly in refineries and petrochemical plants. The improved contaminant removal is achieved by selective purging, by passing gases in the hydrogenation reactor recycle loop or purge stream across membranes selective in favor of the contaminant over hydrogen.

  14. Wilson-loop symmetry breaking reexamined

    NASA Astrophysics Data System (ADS)

    Nakamura, A.; Shiraishi, K.

    1988-12-01

    The splitting in energy of gauge field vacua on the non-simply connected space S 3/Z 2 is reconsidered. We show the calculation to the one-loop level for a Yang-Mills vector with a ghost field. We confirm our previous result and give a solution to the question posed by Freire, Romão and Barroso.

  15. Closed Loop System Identification with Genetic Algorithms

    NASA Technical Reports Server (NTRS)

    Whorton, Mark S.

    2004-01-01

    High performance control design for a flexible space structure is challenging since high fidelity plant models are di.cult to obtain a priori. Uncertainty in the control design models typically require a very robust, low performance control design which must be tuned on-orbit to achieve the required performance. Closed loop system identi.cation is often required to obtain a multivariable open loop plant model based on closed-loop response data. In order to provide an accurate initial plant model to guarantee convergence for standard local optimization methods, this paper presents a global parameter optimization method using genetic algorithms. A minimal representation of the state space dynamics is employed to mitigate the non-uniqueness and over-parameterization of general state space realizations. This control-relevant system identi.cation procedure stresses the joint nature of the system identi.cation and control design problem by seeking to obtain a model that minimizes the di.erence between the predicted and actual closed-loop performance.

  16. Loop Current Eddy formation and baroclinic instability

    NASA Astrophysics Data System (ADS)

    Donohue, K. A.; Watts, D. R.; Hamilton, P.; Leben, R.; Kennelly, M.

    2016-12-01

    The formation of three Loop Current Eddies, Ekman, Franklin, and Hadal, during the period April 2009 through November 2011 was observed by an array of moored current meters and bottom mounted pressure equipped inverted echo sounders. The array design, areal extent nominally 89° W to 85° W, 25° N to 27° N with 30-50 km mesoscale resolution, permits quantitative mapping of the regional circulation at all depths. During Loop Current Eddy detachment and formation events, a marked increase in deep eddy kinetic energy occurs coincident with the growth of a large-scale meander along the northern and eastern parts of the Loop Current. Deep eddies develop in a pattern where the deep fields were offset and leading upper meanders consistent with developing baroclinic instability. The interaction between the upper and deep fields is quantified by evaluating the mean eddy potential energy budget. Largest down-gradient heat fluxes are found along the eastern side of the Loop Current. Where strong, the horizontal down-gradient eddy heat flux (baroclinic conversion rate) nearly balances the vertical down-gradient eddy heat flux indicating that eddies extract available potential energy from the mean field and convert eddy potential energy to eddy kinetic energy.

  17. Aesthetic rehabilitation with multiple loop connectors

    PubMed Central

    Kalra, Ashish; Gowda, Mahesh E.; Verma, Kamal

    2013-01-01

    Patients with a missing tooth along with diastema have limited treatment options to restore the edentulous space. The use of a conventional fixed partial denture (FPD) to replace the missing tooth may result in too wide anterior teeth leading to poor esthetics. The diastema resulting from the missing central incisors can be managed with implant-supported prosthesis or FPD with loop connectors. An old lady reported with chief complaints of missing upper anterior teeth due to trauma. Her past dental history revealed that she was having generalized spacing between her upper anterior teeth. Considering her esthetic requirement of maintaining the diastema between 12, 11, 22, and 21, the treatment option of 06 units porcelain fused to metal FPD from canine to canine with intermittent loop connectors between 21, 22, 11, 12 was planned. Connectors basically link different parts of FPDs. The modified FPD with loop connectors enhanced the natural appearance of the restoration, maintained the diastemas and the proper emergence profile, and preserve the remaining tooth structure of abutment teeth. This clinical report discussed a method for fabrication of a modified FPD with loop connectors to restore the wide span created by missing central incisors. PMID:23853468

  18. Recent Advances in Loop Quantum Cosmology

    NASA Astrophysics Data System (ADS)

    Singh, Parampreet

    2007-04-01

    Einstein's theory of classical general relativity explains the dynamics of our universe at low energies to an excellent precision. However, it breaks down at the Planck scale before the big bang singularity is reached. Relativity thus fails to tell us about the origin of our cosmos and leaves open various questions which are expected to be answered by a quantum theory of gravity. We will review recent developments in loop quantum cosmology which is a quantization of cosmological spacetimes based on loop quantum gravity -- a non-perturbative background independent quantization of gravity. Because, of fundamental discreteness of quantum geometry underlying loop quantum gravity, novel features arise. In particular, for quantum states representing a large classical universe at late times there is an upper bound on the gravitational curvature, of the order of 1/(Planck length)^2. Thus, non-perturbative quantum gravity effects forbid the cosmological dynamics from entering a regime where curvature or energy density blow up. Evolution in loop quantum cosmology is non-singular. In models studied so far, the backward evolution of our expanding universe does not lead to a big bang but a big bounce to a contracting branch when the gravitational curvature reaches Planck scale. These results which have now been established for various homogeneous spacetimes provide a new paradigm of the genesis of our universe and lead to useful insights on the generic resolution of space-like singularities through quantum gravity effects.

  19. A simple second-order digital phase-locked loop.

    NASA Technical Reports Server (NTRS)

    Tegnelia, C. R.

    1972-01-01

    A simple second-order digital phase-locked loop has been designed for the Viking Orbiter 1975 command system. Excluding analog-to-digital conversion, implementation of the loop requires only an adder/subtractor, two registers, and a correctable counter with control logic. The loop considers only the polarity of phase error and corrects system clocks according to a filtered sequence of this polarity. The loop is insensitive to input gain variation, and therefore offers the advantage of stable performance over long life. Predictable performance is guaranteed by extreme reliability of acquisition, yet in the steady state the loop produces only a slight degradation with respect to analog loop performance.

  20. Loop Evolution Observed with AIA and Hi-C

    NASA Technical Reports Server (NTRS)

    Mulu-Moore, Fana; Winebarger, Amy R.; Cirtain, Jonathan W.; Kobayashi, Ken; Korreck, Kelly E.; Golub, Leon; Kuzin, Sergei; Walsh, Robert William; DeForest, Craig E.; De Pontieu, Bart; Title, Alan M.; Weber, Mark

    2012-01-01

    In the past decade, the evolution of EUV loops has been used to infer the loop substructure. With the recent launch of High Resolution Coronal Imager (Hi-C), this inference can be validated. In this presentation we discuss the first results of loop analysis comparing AIA and Hi-C data. In the past decade, the evolution of EUV loops has been used to infer the loop substructure. With the recent launch of High Resolution Coronal Imager (Hi-C), this inference can be validated. In this presentation we discuss the first results of loop analysis comparing AIA and Hi-C data.