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. 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.

  5. Orion Suit Loop Variable Pressure Regulator Development

    NASA Technical Reports Server (NTRS)

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

    2014-01-01

    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 multipule 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 and integrated testing 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 algebraic reduction of one-loop tensor Feynman integrals

    SciTech Connect

    Fleischer, J.; Riemann, T.

    2011-04-01

    We set up a new, flexible approach for the tensor reduction of one-loop Feynman integrals. The 5-point tensor integrals up to rank R=5 are expressed by 4-point tensor integrals of rank R-1, such that the appearance of the inverse 5-point Gram determinant is avoided. The 4-point tensor coefficients are represented in terms of 4-point integrals, defined in d dimensions, 4-2{epsilon}{<=}d{<=}4-2{epsilon}+2(R-1), with higher powers of the propagators. They can be further reduced to expressions which stay free of the inverse 4-point Gram determinants but contain higher-dimensional 4-point integrals with only the first power of scalar propagators, plus 3-point tensor coefficients. A direct evaluation of the higher-dimensional 4-point functions would avoid the appearance of inverse powers of the Gram determinants completely. The simplest approach, however, is to apply here dimensional recurrence relations in order to reduce them to the familiar 2- to 4-point functions in generic dimension d=4-2{epsilon}, introducing thereby coefficients with inverse 4-point Gram determinants up to power R for tensors of rank R. For small or vanishing Gram determinants--where this reduction is not applicable--we use analytic expansions in positive powers of the Gram determinants. Improving the convergence of the expansions substantially with Pade approximants we close up to the evaluation of the 4-point tensor coefficients for larger Gram determinants. Finally, some relations are discussed which may be useful for analytic simplifications of Feynman diagrams.

  12. Loop quantum cosmology with complex Ashtekar variables

    NASA Astrophysics Data System (ADS)

    Ben Achour, Jibril; Grain, Julien; Noui, Karim

    2015-01-01

    We construct and study loop quantum cosmology (LQC) when the Barbero-Immirzi parameter takes the complex value γ =+/- i. We refer to this new approach to quantum cosmology as complex LQC. This formulation is obtained via an analytic continuation of the Hamiltonian constraint (with no inverse volume corrections) from real γ to γ =+/- i, in the simple case of a flat FLRW Universe coupled to a massless scalar field with no cosmological constant. For this, we first compute the non-local curvature operator (defined by the trace of the holonomy of the connection around a fundamental plaquette) evaluated in an arbitrary spin j representation, and find a new close formula for its expression. This allows us to define explicitly a one parameter family of regularizations of the Hamiltonian constraint in LQC, parametrized by the spin j. It is immediate to see that any spin j regularization leads to a bouncing scenario. Then, motivated in particular by previous results on black hole thermodynamics, we perform the analytic continuation of the Hamiltonian constraint to values of the Barbero-Immirzi parameter given by γ =+/- i and to spins j=\\frac{1}{2}(-1+is) where s is real. Even if the area spectrum then becomes continuous, we show that the complex LQC defined in this way does also replace the initial big-bang singularity by a big-bounce. In addition to this, the maximal density and the minimal volume of the Universe are obviously independent of γ . Furthermore, the dynamics before and after the bounce is not symmetrical anymore, which makes a clear distinction between these two phases of the evolution of the Universe.

  13. Outcomes of ACL Reconstruction With Fixed Versus Variable Loop Button Fixation.

    PubMed

    Wise, Brent T; Patel, Nick N; Wier, Garrison; Labib, Sameh A

    2017-03-01

    Suspensory femoral fixation of anterior cruciate ligament (ACL) grafts with fixed loop button and variable loop button devices has gained popularity for ACL reconstruction. This study examined these 2 methods of fixation to determine their effect on graft laxity and patient-reported outcome scores. A database search was performed to identify patients who had undergone ACL reconstruction with either a fixed loop or a variable loop button technique performed by the primary surgeon. Lysholm, Tegner, and 12-Item Short Form Health Survey scores were obtained, and KT-1000 knee ligament arthrometer (MEDmetric, San Diego, California) mechanical knee testing was performed. Results were compared with the uninjured knee. Of the 112 patients who were identified, 91 met the study criteria. Of these patients, 57 completed KT-1000 knee testing, 33 in the variable group and 24 in the fixed group. The average KT-1000 value for the variable group was 0.38 mm, and the average for the closed group was 0.92 mm (P=.19; 95% confidence interval, -0.28 to 1.35). Among the 19 patients in the variable group and the 13 in the closed group who completed the subjective outcomes questionnaires, no statistically significant difference was found. Clinically lax knees (KT-1000>3 mm) were found in 6.1% and 12.5% of patients in the variable group and the fixed group, respectively (P=.2). The variable group had a rerupture rate of 4.7%, whereas the fixed group had a rerupture rate of 8.7% (P=.21). The study found no statistical difference in ACL graft laxity or postoperative functional outcomes between grafts fixed with the variable loop or fixed loop button technique. [Orthopedics. 2017; 40(2):e275-e280.]. Copyright 2016, SLACK Incorporated.

  14. 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.

  15. 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.

  16. Completing the Loop: Linking Software Features to Failures

    NASA Technical Reports Server (NTRS)

    2004-01-01

    The PITS Modification Script has been under development. Testing, debugging, and optimization of the script are in progress. MSIS has begun population of ODC values from historic issue data. Design of the Linker Tool is also continuing. The quarterly review meeting held on December 17,2003, allowed for a venue to discuss installing the PITS Modification Script to the production version of PITS upon completion and incorporation of ODC into an IV&V project s issue tracking process. Feedback from NASA was positive although any global implementation will likely be timed to coordinate with other activities such as establishment of an IV&V Work Breakdown Structure.

  17. 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.

  18. 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.

  19. Closed-Loop Communication Improves Task Completion in Pediatric Trauma Resuscitation.

    PubMed

    El-Shafy, Ibrahim Abd; Delgado, Jennifer; Akerman, Meredith; Bullaro, Francesca; Christopherson, Nathan A M; Prince, Jose M

    2017-08-02

    Pediatric trauma care requires effective and clear communication in a time-sensitive manner amongst a variety of disciplines. Programs such as Crew Resource Management in aviation have been developed to systematically prevent errors. Similarly, teamSTEPPS has been promoted in healthcare with a strong focus on communication. We aim to evaluate the ability of closed-loop communication to improve time-to-task completion in pediatric trauma activations. All pediatric trauma activations from January to September, 2016 at an American College of Surgeons verified level I pediatric trauma center were video recorded and included in the study. Two independent reviewers identified and classified all verbal orders issued by the trauma team leader for order audibility, directed responsibility, check-back, and time-to-task-completion. The impact of pre-notification and level of activation on time-to-task-completion was also evaluated. All analyses were performed using SAS® version 9.4(SAS Institute Inc., Cary, NC). In total, 89 trauma activation videos were reviewed, with 387 verbal orders identified. Of those, 126(32.6%) were directed, 372(96.1%) audible, and 101(26.1%) closed-loop. On average each order required 3.85 minutes to be completed. There was a significant reduction in time-to-task-completion when closed-loop communication was utilized (p < 0.0001). Orders with closed-loop communication were completed 3.6 times sooner as compared to orders with an open-loop [HR = 3.6 (95% CI: 2.5, 5.3)]. There was not a significant difference in time-to-task-completion with respect to pre-notification by emergency service providers (p < 0.6100). [HR = 1.1 (95% CI: 0.9, 1.3)]. There was also not a significant difference in time-to-task-completion with respect to level of trauma team activation (p < 0.2229). [HR = 1.3 (95% CI: 0.8, 2.1)]. While closed-loop communication prevents medical errors, our study highlights the potential to increase the speed and efficiency with which tasks are

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. Completely packed O(n) loop models and their relation with exactly solved coloring models.

    PubMed

    Wang, Yougang; Guo, Wenan; Blöte, Henk W J

    2015-03-01

    We investigate the completely packed O(n) loop model on the square lattice, and its generalization to an Eulerian graph model, which follows by including cubic vertices which connect the four incoming loop segments. This model includes crossing bonds as well. Our study was inspired by existing exact solutions of the so-called coloring model due to Schultz and Perk [Phys. Rev. Lett. 46, 629 (1981)], which is shown to be equivalent with our generalized loop model. We explore the physical properties and the phase diagram of this model by means of transfer-matrix calculations and finite-size scaling. The exact results, which include seven one-dimensional branches in the parameter space of our generalized loop model, are compared to our numerical results. The results for the phase behavior also extend to parts of the parameter space beyond the exactly solved subspaces. One of the exactly solved branches describes the case of nonintersecting loops and was already known to correspond with the ordering transition of the Potts model. Another exactly solved branch, describing a model with nonintersecting loops and cubic vertices, corresponds with a first-order, Ising-like phase transition for n>2. For 12 this branch is the locus of a first-order phase boundary between a phase with a hard-square, lattice-gas-like ordering and a phase dominated by cubic vertices. A mean-field argument explains the first-order nature of this transition.

  6. 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.

  7. 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''.

  8. 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.

  9. Investigating Factorial Invariance of Latent Variables Across Populations When Manifest Variables Are Missing Completely

    PubMed Central

    Widaman, Keith F.; Grimm, Kevin J.; Early, Dawnté R.; Robins, Richard W.; Conger, Rand D.

    2013-01-01

    Difficulties arise in multiple-group evaluations of factorial invariance if particular manifest variables are missing completely in certain groups. Ad hoc analytic alternatives can be used in such situations (e.g., deleting manifest variables), but some common approaches, such as multiple imputation, are not viable. At least 3 solutions to this problem are viable: analyzing differing sets of variables across groups, using pattern mixture approaches, and a new method using random number generation. The latter solution, proposed in this article, is to generate pseudo-random normal deviates for all observations for manifest variables that are missing completely in a given sample and then to specify multiple-group models in a way that respects the random nature of these values. An empirical example is presented in detail comparing the 3 approaches. The proposed solution can enable quantitative comparisons at the latent variable level between groups using programs that require the same number of manifest variables in each group. PMID:24019738

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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. PMID:28405534

  16. Violent Death Reporting in Maryland: Demographic Variability in Data Completeness.

    PubMed

    Smith, Meghan L; Akinyemi, Adebola A; Stanley, Jennifer L; Mitchell, Clifford S

    2017-10-01

    To analyze the completeness of precipitating circumstance information recorded in the Maryland Violent Death Reporting System and identify limitations that could affect the system's utility. We reviewed all violent deaths among Maryland residents for the years 2003 through 2014 (n = 19 161). We assessed the presence of precipitating circumstance data (abstracted from medical examiner and police reports) by manner of death and demographic characteristics. We further evaluated homicide records with multivariable regression. Demographic variation in circumstance reporting was most pronounced for homicide. Circumstances were known for 53.2% of homicide cases, and this percentage was lower among non-Latino Blacks (48.2%), males (50.7%), those aged 18 to 25 years (47.9%), those residing in jurisdictions with higher-than-average homicide rates (46.1%), and those who died outside in a public place (43.4%) or in a correctional facility (48.9%). With the exception of male gender, these factors were significantly associated with circumstance reporting when we controlled for demographic and situational variables. Circumstance reporting was least likely among groups most at risk for homicide in Maryland. Collection of circumstance data for the most affected groups should be strengthened to help develop better prevention strategies.

  17. 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…

  18. 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.

  19. The complete one-loop dilatation operator of planar real β-deformed = 4 SYM theory

    NASA Astrophysics Data System (ADS)

    Fokken, Jan; Sieg, Christoph; Wilhelm, Matthias

    2014-07-01

    We determine the missing finite-size corrections to the asymptotic one-loop dilatation operator of the real β-deformed = 4 SYM theory for the gauge groups U( N) and SU( N) in the 't Hooft limit. In the SU( N) case, the absence of the U(1) field components leads to a new kind of finite-size effect, which we call prewrapping. We classify which states are potentially affected by prewrapping at generic loop orders and comment on the necessity to include it into the integrability-based description. As a further result, we identify classes of n-point correlation functions which at all loop orders in the planar theory are given by the values of their undeformed counterparts. Finally, we determine the superconformal multiplet structure and one-loop anomalous dimensions of all single-trace states with classical scaling dimension Δ0 ≤ 4.5.

  20. Testing of a Loop Heat Pipe Subjected to Variable Accelerating Forces

    NASA Technical Reports Server (NTRS)

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

    2000-01-01

    This paper presents viewgraphs of the functionality of a loop heat pipe that was subjected to variable accelerating forces. The topics include: 1) Summary of LHP (Loop Heat Pipe) Design Parameters; 2) Picture of the LHP; 3) Schematic of Test Setup; 4) Test Configurations; 5) Test Profiles; 6) Overview of Test Results; 7) Start-up; 8) Typical Start-up without Temperature Overshoot; 9) Start-up with a Large Temperature Overshoot; 10) LHP Operation Under Stationary Condition; 11) LHP Operation Under Continuous Acceleration; 12) LHP Operation Under Periodic Acceleration; 13) Effects of Acceleration on Temperature Oscillation and Hysteresis; 14) Temperature Oscillation/Hysteresis vs Spin Rate; and 15) Summary.

  1. 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.

  2. Closed-loop control of grasping with a myoelectric hand prosthesis: which are the relevant feedback variables for force control?

    PubMed

    Ninu, Andrei; Dosen, Strahinja; Muceli, Silvia; Rattay, Frank; Dietl, Hans; Farina, Dario

    2014-09-01

    In closed-loop control of grasping by hand prostheses, the feedback information sent to the user is usually the actual controlled variable, i.e., the grasp force. Although this choice is intuitive and logical, the force production is only the last step in the process of grasping. Therefore, this study evaluated the performance in controlling grasp strength using a hand prosthesis operated through a complete grasping sequence while varying the feedback variables (e.g., closing velocity, grasping force), which were provided to the user visually or through vibrotactile stimulation. The experiments were conducted on 13 volunteers who controlled the Otto Bock Sensor Hand Speed prosthesis. Results showed that vibrotactile patterns were able to replace the visual feedback. Interestingly, the experiments demonstrated that direct force feedback was not essential for the control of grasping force. The subjects were indeed able to control the grip strength, predictively, by estimating the grasping force from the prosthesis velocity of closing. Therefore, grasping without explicit force feedback is not completely blind, contrary to what is usually assumed. In our study we analyzed grasping with a specific prosthetic device, but the outcomes are also applicable for other devices, with one or more degrees-of-freedom. The necessary condition is that the electromyography (EMG) signal directly and proportionally controls the velocity/grasp force of the hand, which is a common approach among EMG controlled prosthetic devices. The results provide important indications on the design of closed-loop EMG controlled prosthetic systems.

  3. A complete mock circulation loop for the evaluation of left, right, and biventricular assist devices.

    PubMed

    Timms, Daniel; Hayne, Mark; McNeil, Keith; Galbraith, Andrew

    2005-07-01

    A new mock circulation loop was developed to replicate the necessary features of the systemic and pulmonic circulatory systems, including pulsatile left and right ventricles coupled with vascular compliances and resistances. A brief description of the mock loop construction is provided before results are presented confirming the recreation of perfusion rates and pressures found in the natural systemic and pulmonic vascular trees for a normal and failing heart at rest. This rig provides the ability to evaluate the hemodynamic effect of left, right, and biventricular assist devices in vitro. The small and compact mock circulation rig has the potential to reduce device evaluation costs by simulating the natural circulatory system, thus providing valuable device performance feedback prior to expensive in vivo animal trials.

  4. Structure and Variability of the Loop Current along the Yucatan Slope and Shelf Break.

    NASA Astrophysics Data System (ADS)

    Sheinbaum, J.; Athie, G.; Candela, J.; Ochoa, J.; Romero, A.

    2016-02-01

    Yucatan Current and Loop Current variability is investigated using data from an array of moorings that was deployed during 2006-2011 at the western Yucatan Channel and two other strategic cross-sections further north over the Campeche Bank, where the core and western edge of the currents are usually located. Measurements show the cores of the Yucatan Current and Loop Current have a more offshore (onshore) position in summer (winter-spring) suggesting seasonality and a relation to transport variations. Some eastward displacements of the currents are associated with periods of positive horizontal shear (cyclonic vorticity anomalies) propagating northward from the Caribbean coast of Mexico into the Gulf. Ten of the thirteen Loop Current eddies released between 2006 and 2011 were found to be clearly related to these propagating cyclonic anomalies that after crossing the Yucatan Channel produce intense pulses of eddy kinetic energy in the mooring sections downstream. Current structure and variability above and below 1000 m depth have very different characteristics. Diffferences are also found between western and eastern mooring measurements at similar depths. Wind forcing, coastally trapped waves and small scale frontal eddies appear to be the source of this east-west asymmetry.

  5. Complete two loop bosonic contributions to the muon lifetime in the standard model.

    PubMed

    Awramik, M; Czakon, M

    2002-12-09

    The last missing correction to the muon lifetime in the standard model at O(alpha(2)) coming from gauge and Higgs boson loops is presented. The associated contribution to the parameter Deltar in the on-shell scheme ranges from 6x10(-5) to -4x10(-5) for Higgs boson masses from 100 GeV to 1 TeV. This result translates into a shift of the W boson mass which does not exceed +/-1 MeV in the same range and amounts, in particular, to approximately -0.8 MeV for a 115 GeV Higgs boson.

  6. Complete one-loop calculation of electroweak supersymmetric effects in t-channel single top production at CERN LHC

    SciTech Connect

    Beccaria, M.; Calame, C. M. Carloni; Macorini, G.; Verzegnassi, C.; Mirabella, E.; Piccinini, F.; Renard, F. M.

    2008-06-01

    We have computed the complete one-loop electroweak effects in the minimal supersymmetric standard model for single top (and single antitop) production in the t channel at hadron colliders, generalizing a previous analysis performed for the dominant dt final state and fully including QED effects. The results are quite similar for all processes. The overall standard model one-loop effect is small, of the few percent size. This is due to a compensation of weak and QED contributions that are of opposite sign. The genuine supersymmetry contribution is generally quite modest in the minimal supergravity scenario. The experimental observables would therefore only practically depend, in this framework, on the Cabibbo-Kobayashi-Maskawa Wtb coupling.

  7. 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.

  8. 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. 

  9. 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.

  10. Characteristics of three-phase internal loop airlift bioreactors with complete gas recirculation for non-Newtonian fluids.

    PubMed

    Wen, Jianping; Jia, Xiaoqiang; Cheng, Xianrui; Yang, Peng

    2005-05-01

    Hydrodynamic and gas-liquid mass transfer characteristics, such as liquid velocity, gas holdup, solid holdup and gas-liquid volumetric mass transfer coefficient, in the riser and downcomer of the gas-liquid-solid three-phase internal loop airlift bioreactors with complete gas recirculation for non-Newtonian fluids, were investigated. A mathematical model for the description of flow behavior and gas-liquid mass transfer of these bioreactors was developed. The predicted results of this model agreed well with the experimental data.

  11. Replica variables, loop expansion, and spectral rigidity of random-matrix ensembles

    SciTech Connect

    Verbaarschot, J.J.M.; Zirnbauer, M.R.

    1984-11-01

    The replica trick of statistical mechanics is used to derive integral representations of n-point Green's functions both for the GOE and the EGOE. These integral representations are particularly suited for perturbative evaluation (loop expansion). Using the one-loop correction to the GOE one-point function, it is found that the density of states at the edge of the semi-circle scales is approx.N/sup -1/3/rho(N/sup 2/3/delta) where N is the dimension of the matrix ensemble. For the n-point functions with n> or =2, the existence of the microscopic limit to all orders in N/sup -1/ is proved by decomposing the integration variables into massive (i.e., macroscopic) and massless (microscopic) components. Evaluation of the EGOE two-point function to leading order in the inverse local distance variable yields the first analytic evidence that the long-range correlations of EGOE spectra are similar to the GOE but not-stationary.

  12. 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.

  13. Variability of Insulin Requirements Over 12 Weeks of Closed-Loop Insulin Delivery in Adults With Type 1 Diabetes.

    PubMed

    Ruan, Yue; Thabit, Hood; Leelarathna, Lalantha; Hartnell, Sara; Willinska, Malgorzata E; Dellweg, Sibylle; Benesch, Carsten; Mader, Julia K; Holzer, Manuel; Kojzar, Harald; Evans, Mark L; Pieber, Thomas R; Arnolds, Sabine; Hovorka, Roman

    2016-05-01

    To quantify variability of insulin requirements during closed-loop insulin delivery. We retrospectively analyzed overnight, daytime, and total daily insulin amounts delivered during a multicenter closed-loop trial involving 32 adults with type 1 diabetes. Participants applied hybrid day-and-night closed-loop insulin delivery under free-living home conditions over 12 weeks. The coefficient of variation was adopted to measure variability of insulin requirements in individual subjects. Data were analyzed from 1,918 nights, 1,883 daytime periods and 1,564 total days characterized by closed-loop use over 85% of time. Variability of overnight insulin requirements (mean [SD] coefficient of variation 31% [4]) was nearly twice as high as variability of total daily requirements (17% [3], P < 0.001) and was also higher than variability of daytime insulin requirements (22% [4], P < 0.001). Overnight insulin requirements were significantly more variable than daytime and total daily amounts. This may explain why some people with type 1 diabetes report frustrating variability in morning glycemia. © 2016 by the American Diabetes Association. Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and the work is not altered.

  14. 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.

  15. Universal Quantum Computing with Measurement-Induced Continuous-Variable Gate Sequence in a Loop-Based Architecture

    NASA Astrophysics Data System (ADS)

    Takeda, Shuntaro; Furusawa, Akira

    2017-09-01

    We propose a scalable scheme for optical quantum computing using measurement-induced continuous-variable quantum gates in a loop-based architecture. Here, time-bin-encoded quantum information in a single spatial mode is deterministically processed in a nested loop by an electrically programmable gate sequence. This architecture can process any input state and an arbitrary number of modes with almost minimum resources, and offers a universal gate set for both qubits and continuous variables. Furthermore, quantum computing can be performed fault tolerantly by a known scheme for encoding a qubit in an infinite-dimensional Hilbert space of a single light mode.

  16. 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…

  17. 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

  18. Patients' Evaluations of Complete Denture Therapy and Their Association with Related Variables: A Pilot Study.

    PubMed

    Santos, Beatriz Ferreira Oliveira; dos Santos, Mateus Bertolini Fernandes; Santos, Jarbas Francisco Fernandes; Marchini, Leonardo

    2015-07-01

    Patient satisfaction is an important goal in complete denture therapy, and many factors influence this parameter. This study aimed to evaluate expectations before and satisfaction after therapy with complete dentures. As a secondary objective, other variables that may interfere with patient satisfaction were also evaluated. A representative sample of 99 patients assigned visual analog scale (VAS) scores to their expectations before and satisfaction after therapy regarding chewing, esthetics, comfort, and phonetics. Demographic data and answers to a questionnaire concerning the dentists' conduct were recorded. Multiple linear regression was used to evaluate the association among studied variables and patients' expectation and satisfaction with their dentures. The average VAS scores were high for both expectations and satisfaction, and satisfaction exceeded expectations. Patients' expectations about esthetics and comfort were associated with age and self-reported time of using complete dentures. Patient satisfaction regarding chewing was associated with the number of postdelivery adjustments. Also, patient satisfaction regarding esthetics was associated with gender and esthetic expectations. In regard to phonetic satisfaction, associations were verified among self-reported time of using complete dentures, comfort and phonetics expectations, and dentists' explanations. Comfort satisfaction was associated only with educational level. Patient satisfaction regarding complete dentures exceeded expectations and an expressive majority of positive evaluations of the dentists was noticed. Many patient-related variables seemed to influence their evaluations of their dentures. © 2015 by the American College of Prosthodontists.

  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. Kink oscillations of cooling coronal loops with variable cross-section

    NASA Astrophysics Data System (ADS)

    Ruderman, M. S.; Shukhobodskiy, A. A.; Erdélyi, R.

    2017-06-01

    We study kink waves and oscillations in a thin expanding magnetic tube in the presence of flow. The tube consists of a core region and a thin transitional region at the tube boundary. In this region the plasma density monotonically decreases from its value in the core region to the value outside the tube. Both the plasma density and velocity of background flow vary along the tube and in time. Using the multiscale expansions we derive the system of two equations describing the kink oscillations. When there is no transitional layer the oscillations are described by the first of these two equations. We use this equation to study the effect of plasma density variation with time on kink oscillations of an expanding tube with a sharp boundary. We assume that the characteristic time of the density variation is much greater than the characteristic time of kink oscillations. Then we use the Wentzel-Kramer-Brillouin (WKB) method to derive the expression for the adiabatic invariant, which is the quantity that is conserved when the plasma density varies. The general theoretical results are applied to the kink oscillations of coronal magnetic loops. We consider an expanding loop with the half-circle shape and assume that the plasma temperature inside a loop decays exponentially with time. We numerically calculated the dependences of the fundamental mode frequency, the ratio of frequencies of the first overtone and fundamental mode, and the oscillation amplitude on time. We obtained that the oscillation frequency and amplitude increase and the frequency ratio decreases due to cooling. The amplitude increase is stronger for loops with a greater expansion factor. This effect is also more pronounced for higher loops. However, it is fairly moderate even for loops that are quite high.

  1. 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

  2. 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.

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

    NASA Astrophysics Data System (ADS)

    Niccoli, G.

    2013-05-01

    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.

  4. 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.

  5. Completing the audit cycle: the impact of an electronic reporting system on the feedback loop in surgical specialties.

    PubMed

    Mandavia, Rishi; Yassin, Gada; Dhar, Vikram; Jacob, Tony

    2013-01-01

    The feedback loop of incident reporting is essential in improving patient care. Few studies have followed the loop around its cycle and little data are available concerning the impact of interventions. We investigated the feedback loop before and after the implementation of an electronic reporting system. Data were collected before and after our intervention. Data were analyzed in terms of the percentage of incidents evaluated, the percentage of incidents resulting in action, whether correlations demonstrated an increased rate of action taken as incident risk score increased. Prior to our intervention, 43% and 40% of incidents reported were evaluated and acted upon, respectively. Postintervention, the number of incidents reported increased by 198%. All incidents were evaluated and 66% were acted upon. Both pre- and postintervention, no correlations demonstrated an increase in action taken as incident severity increased. Our intervention resulted in a considerable increase in the number of incidents reported, evaluated, and acted upon. Such an effect would be expected to improve patient safety, although further studies are needed to definitively confirm this. We therefore recommend the use of electronic systems and further studies to evaluate their impact on patient safety. © 2013 National Association for Healthcare Quality.

  6. 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.

  7. 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.

  8. Complete two-loop electroweak fermionic corrections to the effective leptonic weak mixing angle sin2theta(lept)eff and indirect determination of the Higgs Boson Mass.

    PubMed

    Awramik, M; Czakon, M; Freitas, A; Weiglein, G

    2004-11-12

    We present a complete calculation of the contributions to the effective leptonic weak mixing angle, sin((2)theta;(lept)(eff), generated by closed fermion loops at the two-loop level of the electroweak interactions. This quantity is the source of the most stringent bound on the mass M(H) of the standard model Higgs boson. The size of the corrections with respect to known partial results varies between -4 x 10(-5) and -8 x 10(-5) for a realistic range of M(H) from 100 to 300 GeV. This translates into a shift of the predicted (from sin((2)theta;(lept)(eff) alone) central value of M(H) by +19 GeV, to be compared with the shift induced by a recent change in the measured top quark mass which amounts to +36 GeV.

  9. 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.

  10. 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.

  11. 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.

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

    PubMed

    Gao, Yu-Shi; Jia, Xiao-Xu; 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.

  13. 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

  14. Looping: An Empirical Evaluation

    ERIC Educational Resources Information Center

    Cistone, Peter; Shneyderman, Aleksandr

    2004-01-01

    Looping is the practice in which a teacher instructs the same group of students for at least two school years, following them from one grade level to the next. Once a "loop" of two or more years is completed, the teacher may start a new loop teaching a new group of students. This evaluation study of the practice of looping in a large…

  15. Closed-loop control of a shape memory alloy actuation system for variable area fan nozzle

    NASA Astrophysics Data System (ADS)

    Barooah, Prabir; Rey, Nancy

    2002-07-01

    Shape Memory Alloys have been used in a wide variety of actuation applications. A bundled shape memory alloy cable actuator, capable of providing large force and displacement has been developed by United Technologies Corporation (patents pending) for actuating a Variable Area fan Nozzle (VAN). The ability to control fan nozzle exit area is an enabling technology for the next generation turbofan engines. Performance benefits for VAN engines are estimated to be up to 9% in Thrust Specific Fuel Consumption (TSFC) compared to traditional fixed geometry designs. The advantage of SMA actuated VAN design is light weight and low complexity compared to conventionally actuated designs. To achieve the maximum efficiency from a VAN engine, the nozzle exit area has to be continuously varied for a certain period of time during climb, since the optimum nozzle exit area is a function of several flight variables (flight Mach number, altitude etc). Hence, the actuator had to be controlled to provide the time varying desired nozzle area. A new control algorithm was developed for this purpose, which produced the desired flap area by metering the resistive heating of the SMA actuator. Since no active cooling was used, reducing overshoot was a significant challenge of the controller. A full scale, 2 flap model of the VAN system was built, which was capable of simulating a 20% nozzle area variation, and tested under full scale aerodynamic load in NASA Langley Jet Exit Test facility. The controller met all the requirements of the actuation system and was able to drive the flap position to the desired position with less than 2% overshoot in step input tests. The controller is based on a adaptive algorithm formulation with logical switches that reduces its overshoot error. Although the effectiveness of the controller was demonstrated in full scale model tests, no theoretical results as to its stability and robustness has been derived. Stability of the controller will have to be investigated

  16. 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…

  17. 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…

  18. 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.

  19. Unlike the quaternary structure transition, the tertiary structure change of the 240s loop in allosteric aspartate transcarbamylase requires active site saturation by substrate for completion.

    PubMed

    Fetler, L; Vachette, P; Hervé, G; Ladjimi, M M

    1995-12-05

    The quaternary structural change associated with the homotropic cooperative interactions in Escherichia coli aspartate transcarbamylase (ATCase) is accompanied by various tertiary structural modifications; the most notable one involves the 240s loop formed by residues 230--245 of the catalytic chain. In order to monitor local conformational changes in this region by fluorescence spectroscopy, Tyr-240 has been replaced by a Trp residue, in a mutant enzyme, in which both naturally occurring Trp residues in positions 209 and 284 of the catalytic chains had previously been substituted by Phe residues. This F209F284W240-ATCase still displays homotropic cooperativity for aspartate and undergoes the same T to R quaternary structure change as does the wild-type enzyme. Upon binding of the bisubstrate analogue N-(phosphonoacetyl)-L-aspartate, the fluorescence emission spectrum of this mutant shows a red shift directly proportional to the fraction of catalytic sites occupied by this compound, a maximum value of 4 nm being attained when all six active sites are ligated. An identical shift is observed with the catalytic subunits of this modified enzyme, when all three active sites are occupied. In contrast, the quaternary structural change of the F209F284W240-ATCase, monitored by small-angle X-ray scattering, is complete when only four out of six catalytic sites are occupied. Thus, the 240s loop adopts its final conformation only when the neighboring active site is bound.

  20. 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.

  1. 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.

  2. 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.

  3. 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 Central

    Nakane, Shuhei; Iwamoto, Aikichi; Matsuda, Zene

    2015-01-01

    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. PMID:25911103

  4. Design of Experiments with Multiple Independent Variables: A Resource Management Perspective on Complete and Reduced Factorial Designs

    ERIC Educational Resources Information Center

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

    2009-01-01

    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.…

  5. 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

  6. A model study of the vertically integrated transport variability through the Yucatan Channel: Role of Loop Current evolution and flow compensation around Cuba

    NASA Astrophysics Data System (ADS)

    Lin, Yuehua; Greatbatch, Richard J.; Sheng, Jinyu

    2009-08-01

    The relationship between Loop Current intrusion in the Gulf of Mexico and vertically integrated transport variations through the Yucatan Channel is examined using models and the available observations. Transport in the model is found to be a minimum when the Loop Current intrudes strongly into the Gulf of Mexico, typically just before a ring is shed, and to be a maximum during the next growth phase in association with the buildup of warm water off the northwest coast of Cuba. We argue that the transport variations are part of a "compensation effect" in which transport variations through the Yucatan Channel are at least partly compensated by flow around Cuba. Numerical experiments show that the transport variations result from the interaction between the density anomalies associated with Loop Current intrusion and the variable bottom topography. The compensation effect is also shown to operate at shorter time scales (less than 30 days) in association with wind forcing.

  7. 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

  8. The complete mitochondrial genome sequence of the Mormon cricket (Anabrus simplex: Tettigoniidae: Orthoptera) and an analysis of control region variability.

    PubMed

    Fenn, J D; Cameron, S L; Whiting, M F

    2007-04-01

    The Anabrus simplex is a swarming plague orthopteran found in western North America. The genome is 15 766 bp in length and genome organization follows the ancestral insect gene arrangement. atp6 lacked any readily identifiable stop codon. Examination of mRNA secondary structure for this gene suggested a stem/loop-mediated mRNA post-transcriptional processing to liberate a mature atp6 mRNA with a complete stop codon produced by polyadenylation. Comparison of similar protein with protein gene boundaries in other insect species reveal a general mechanism for mRNA excision and provide further supporting evidence for post-transcriptional mRNA processing in mitochondrial genomes. The A + T-rich region, or control region, was sequenced for 55 A. simplex individuals from 12 different populations. Variance studies between these individuals show that the A + T-rich region contains significant phylogenetic signal to be used in population studies.

  9. 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

  10. 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.

  11. 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

  12. 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.

  13. 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

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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

  1. 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…

  2. 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…

  3. The Relationship Between Deep Flows in the Yucatan Channel and the Variability of the Loop Current Extension

    NASA Astrophysics Data System (ADS)

    Bunge, L.; Ochoa, J.; Candela, J.; Badan, A.; Sheinbaum, J.

    2001-12-01

    The Gulf of Mexico and the Caribbean Sea exchange waters through the Yucatan Channel. The most conspicuous current in the area is the Yucatan Current, which once it enters the Gulf of Mexico, becomes the Loop Current. This warm surface current eventually exits the Gulf through the Florida Straits. The extension of the Loop Current varies considerably as the result of unequal transports in Yucatan and Florida. Since the changes in the Gulf of Mexico water volume are small, the volume occupied by these surface waters must be compensated by outflows or inflows in the deeper layers. Exchanges deeper than the Florida sill (about 730 m) may only occur in the Yucatan Channel. Eight moorings of ADCPs, current meters and thermometers were deployed across the Yucatan Channel from September 8th 1999 to June 17th 2000. The data from these arrays were used to compute time series of transports below the 6oC isotherm, the lowest temperature observed in the Florida Straits. The surface extension of the Loop Current was inferred from three-day AVHRR imagery. Weak temperature gradients during summer make the evaluation of Loop Current areas possible only from October 17th to May 10th. There are two ways to compare the deep transports and the extension of the Loop Current: the first way is to integrate transports and compare them with the surface warm water extension. The second is to relate the time derivate of the extension of the current with the transports. In the first case, which favors low frequencies, the correlation coefficient is 0.94 for the raw series, and 0.91 using a running average of 20 days and removing the trend from the series. In the second case the correlation coefficient is not significant for the raw series but reaches 0.62 when using a running average of 20 days, and up to 0.83 with a lag of 8.5 days. In both cases it is clear that these correlations are not only for the lowest frequency of the series, but also for periods of approximately 40 days.

  4. Unbiased, scalable sampling of protein loop conformations from probabilistic priors

    PubMed Central

    2013-01-01

    Background Protein loops are flexible structures that are intimately tied to function, but understanding loop motion and generating loop conformation ensembles remain significant computational challenges. Discrete search techniques scale poorly to large loops, optimization and molecular dynamics techniques are prone to local minima, and inverse kinematics techniques can only incorporate structural preferences in adhoc fashion. This paper presents Sub-Loop Inverse Kinematics Monte Carlo (SLIKMC), a new Markov chain Monte Carlo algorithm for generating conformations of closed loops according to experimentally available, heterogeneous structural preferences. Results Our simulation experiments demonstrate that the method computes high-scoring conformations of large loops (>10 residues) orders of magnitude faster than standard Monte Carlo and discrete search techniques. Two new developments contribute to the scalability of the new method. First, structural preferences are specified via a probabilistic graphical model (PGM) that links conformation variables, spatial variables (e.g., atom positions), constraints and prior information in a unified framework. The method uses a sparse PGM that exploits locality of interactions between atoms and residues. Second, a novel method for sampling sub-loops is developed to generate statistically unbiased samples of probability densities restricted by loop-closure constraints. Conclusion Numerical experiments confirm that SLIKMC generates conformation ensembles that are statistically consistent with specified structural preferences. Protein conformations with 100+ residues are sampled on standard PC hardware in seconds. Application to proteins involved in ion-binding demonstrate its potential as a tool for loop ensemble generation and missing structure completion. PMID:24565175

  5. 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.

  6. Design of Experiments with Multiple Independent Variables: A Resource Management Perspective on Complete and Reduced Factorial Designs

    PubMed Central

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

    2009-01-01

    An investigator who plans to conduct experiments 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 four design options are compared: complete factorial, individual experiments, single factor, and fractional factorial designs. 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. PMID:19719358

  7. 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.

  8. 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.

  9. 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

  10. Modeling Day-to-Day Variability of Glucose-Insulin Regulation Over 12-Week Home Use of Closed-Loop Insulin Delivery.

    PubMed

    Yue Ruan; Wilinska, Malgorzata E; Thabit, Hood; Hovorka, Roman

    2017-06-01

    Parameters of physiological models of glucose-insulin regulation in type 1 diabetes have previously been estimated using data collected over short periods of time and lack the quantification of day-to-day variability. We developed a new hierarchical model to relate subcutaneous insulin delivery and carbohydrate intake to continuous glucose monitoring over 12 weeks while describing day-to-day variability. Sensor glucose data sampled every 10-min, insulin aspart delivery and meal intake were analyzed from eight adults with type 1 diabetes (male/female 5/3, age 39.9 ± 9.5 years, BMI 25.4 ± 4.4kg/m(2), HbA1c 8.4 ± 0.6% ) who underwent a 12-week home study of closed-loop insulin delivery. A compartment model comprised of five linear differential equations; model parameters were estimated using the Markov chain Monte Carlo approach within a hierarchical Bayesian model framework. Physiologically, plausible a posteriori distributions of model parameters including insulin sensitivity, time-to-peak insulin action, time-to-peak gut absorption, and carbohydrate bioavailability, and good model fit were observed. Day-to-day variability of model parameters was estimated in the range of 38-79% for insulin sensitivity and 27-48% for time-to-peak of insulin action. In conclusion, a linear Bayesian hierarchical approach is feasible to describe a 12-week glucose-insulin relationship using conventional clinical data. The model may facilitate in silico testing to aid the development of closed-loop insulin delivery systems.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  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. Characterization of a complete immunoglobulin heavy-chain variable region germ-line gene of rainbow trout.

    PubMed

    Matsunaga, T; Chen, T; Törmänen, V

    1990-10-01

    A germ-line heavy-chain variable region (VH) gene (RTVH431) has been isolated from a rainbow trout (Salmo gairdneri) and characterized by complete nucleotide sequencing. It is characteristic of VH, as shown by the conserved octamer and TATA motif in the 5' region, the heptamernonamer recombination signal sequence in the 3' region, and the 18-amino-acid-long hydrophobic leader interrupted by an intron. The 98-amino-acid-long VH coding region has 50-70% nucleotide sequence homology and 40-60% amino acid sequence homology with VHS of various vertebrate species. We have also found unique or species-specific amino acid residues in the VHS of rainbow trout, amphibia (Xenopus), reptile (Caiman), and shark (Heterodontus) in our sequence analyses. The RTVH431 has an unusual amino acid in the conserved 34th position in complementarity-determining region 1 of VH. Southern hybridization results suggest the presence of a large gene family related to RTVH431 in the trout genome. The complex evolution of antibody V genes is discussed.

  17. Characterization of a complete immunoglobulin heavy-chain variable region germ-line gene of rainbow trout.

    PubMed Central

    Matsunaga, T; Chen, T; Törmänen, V

    1990-01-01

    A germ-line heavy-chain variable region (VH) gene (RTVH431) has been isolated from a rainbow trout (Salmo gairdneri) and characterized by complete nucleotide sequencing. It is characteristic of VH, as shown by the conserved octamer and TATA motif in the 5' region, the heptamernonamer recombination signal sequence in the 3' region, and the 18-amino-acid-long hydrophobic leader interrupted by an intron. The 98-amino-acid-long VH coding region has 50-70% nucleotide sequence homology and 40-60% amino acid sequence homology with VHS of various vertebrate species. We have also found unique or species-specific amino acid residues in the VHS of rainbow trout, amphibia (Xenopus), reptile (Caiman), and shark (Heterodontus) in our sequence analyses. The RTVH431 has an unusual amino acid in the conserved 34th position in complementarity-determining region 1 of VH. Southern hybridization results suggest the presence of a large gene family related to RTVH431 in the trout genome. The complex evolution of antibody V genes is discussed. Images PMID:2120708

  18. 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.

  19. Unique structure of the M loop region of β1-tubulin may contribute to size variability of platelets in the family Felidae.

    PubMed

    Boudreaux, Mary K; Osborne, Christina D; Herre, Adam C; Rivera, Elliot Ramos; Spangler, Elizabeth A

    2010-12-01

    Platelet size is relatively uniform in mammals except for domestic cats. Uniform platelet production by megakaryocytes can be disrupted if microtubule assembly or dynamics is impaired. Mutations in the gene encoding β1-tubulin have been documented in dogs and people, and the resulting microtubule effects have been associated with production of large platelets. The objectives of this study were to evaluate morphology of platelets on feline blood smears, determine the gene sequences encoding β1-tubulin in members of the family Felidae, and compare the findings with those in other mammalian species to determine whether predicted structural differences in β1-tubulin that might affect microtubule stability or assembly were present. At least 100 platelets/smear on blood smears from 15 domestic cats and 88 big cats were evaluated to assess platelet size variability. Platelet-derived cDNA obtained from a domestic cat and genomic DNA isolated from blood samples of domestic cats and other members of the family Felidae were analyzed by PCR using primers specific for β1-tubulin. Gene sequences obtained were compared with those of other common mammals. Two differences in gene sequence were found in a highly conserved region encoding the M loop of β1-tubulin in members of the family Felidae compared with sequences from other species. Platelet size variation was present in big cats and domestic cats. In addition, a rare amino acid change was documented in the C-terminal region encoding the H11 helix in domestic cats. Members of the family Felidae have an altered M loop region in β1-tubulin compared with other mammals. This variation may contribute to the observed platelet size variability. ©2010 American Society for Veterinary Clinical Pathology.

  20. 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.

  1. Tyrosine sulfation in the second variable loop (V2) of HIV-1 gp120 stabilizes V2-V3 interaction and modulates neutralization sensitivity.

    PubMed

    Cimbro, Raffaello; Gallant, Thomas R; Dolan, Michael A; Guzzo, Christina; Zhang, Peng; Lin, Yin; Miao, Huiyi; Van Ryk, Donald; Arthos, James; Gorshkova, Inna; Brown, Patrick H; Hurt, Darrell E; Lusso, Paolo

    2014-02-25

    Elicitation of broadly neutralizing antibodies is essential for the development of a protective vaccine against HIV-1. However, the native HIV-1 envelope adopts a protected conformation that conceals highly conserved sites of vulnerability from antibody recognition. Although high-definition structures of the monomeric core of the envelope glycoprotein subunit gp120 and, more recently, of a stabilized soluble gp140 trimer have been solved, fundamental aspects related to the conformation and function of the native envelope remain unresolved. Here, we show that the conserved central region of the second variable loop (V2) of gp120 contains sulfated tyrosines (Tys173 and Tys177) that in the CD4-unbound prefusion state mediate intramolecular interaction between V2 and the conserved base of the third variable loop (V3), functionally mimicking sulfated tyrosines in CCR5 and anti-coreceptor-binding-site antibodies such as 412d. Recombinant gp120 expressed in continuous cell lines displays low constitutive levels of V2 tyrosine sulfation, which can be enhanced markedly by overexpression of the tyrosyl sulfotransferase TPST2. In contrast, virion-associated gp120 produced by primary CD4(+) T cells is inherently highly sulfated. Consistent with a functional role of the V2 sulfotyrosines, enhancement of tyrosine sulfation decreased binding and neutralization of HIV-1 BaL by monomeric soluble CD4, 412d, and anti-V3 antibodies and increased recognition by the trimer-preferring antibodies PG9, PG16, CH01, and PGT145. Conversely, inhibition of tyrosine sulfation increased sensitivity to soluble CD4, 412d, and anti-V3 antibodies and diminished recognition by trimer-preferring antibodies. These results identify the sulfotyrosine-mediated V2-V3 interaction as a critical constraint that stabilizes the native HIV-1 envelope trimer and modulates its sensitivity to neutralization.

  2. Enhancing automatic closed-loop glucose control in type 1 diabetes with an adaptive meal bolus calculator - in silico evaluation under intra-day variability.

    PubMed

    Herrero, Pau; Bondia, Jorge; Adewuyi, Oloruntoba; Pesl, Peter; El-Sharkawy, Mohamed; Reddy, Monika; Toumazou, Chris; Oliver, Nick; Georgiou, Pantelis

    2017-07-01

    Current prototypes of closed-loop systems for glucose control in type 1 diabetes mellitus, also referred to as artificial pancreas systems, require a pre-meal insulin bolus to compensate for delays in subcutaneous insulin absorption in order to avoid initial post-prandial hyperglycemia. Computing such a meal bolus is a challenging task due to the high intra-subject variability of insulin requirements. Most closed-loop systems compute this pre-meal insulin dose by a standard bolus calculation, as is commonly found in insulin pumps. However, the performance of these calculators is limited due to a lack of adaptiveness in front of dynamic changes in insulin requirements. Despite some initial attempts to include adaptation within these calculators, challenges remain. In this paper we present a new technique to automatically adapt the meal-priming bolus within an artificial pancreas. The technique consists of using a novel adaptive bolus calculator based on Case-Based Reasoning and Run-To-Run control, within a closed-loop controller. Coordination between the adaptive bolus calculator and the controller was required to achieve the desired performance. For testing purposes, the clinically validated Imperial College Artificial Pancreas controller was employed. The proposed system was evaluated against itself but without bolus adaptation. The UVa-Padova T1DM v3.2 system was used to carry out a three-month in silico study on 11 adult and 11 adolescent virtual subjects taking into account inter-and intra-subject variability of insulin requirements and uncertainty on carbohydrate intake. Overall, the closed-loop controller enhanced by an adaptive bolus calculator improves glycemic control when compared to its non-adaptive counterpart. In particular, the following statistically significant improvements were found (non-adaptive vs. adaptive). Adults: mean glucose 142.2 ± 9.4vs. 131.8 ± 4.2mg/dl; percentage time in target [70, 180]mg/dl, 82.0 ± 7.0vs. 89.5 ± 4

  3. 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.

  4. 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.

  5. 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.

  6. Varietal Loops

    NASA Image and Video Library

    2016-09-15

    A series of active regions stretched along the right side of the sun exhibited a wide variety of loops cascading above them (Sept. 12-14, 2016). The active region near the center has tightly coiled loops, while the region rotating over the right edge has some elongated and some very stretched loops above it. The loops are actually charged particles spiraling along magnetic field lines, observed here in a wavelength of extreme ultraviolet light. Near the middle of the video the Earth quickly passes in front of a portion of the sun as viewed by SDO. http://photojournal.jpl.nasa.gov/catalog/PIA16997

  7. Complete multiwavelength evolution of galactic black hole transients during outburst decay. II. Compact jets and X-ray variability properties

    SciTech Connect

    Dinçer, T.; Kalemci, E.; Tomsick, J. A.; Buxton, M. M.; Bailyn, C. D.

    2014-11-01

    We investigated the relation between compact jet emission and X-ray variability properties of all black hole transients with multiwavelength coverage during their outburst decays. We studied the evolution of all power spectral components (including low-frequency quasi-periodic oscillations; QPOs), and related this evolution to changes in jet properties tracked by radio and infrared observations. We grouped sources according to their tracks in the radio/X-ray luminosity relation and show that the standards show stronger broadband X-ray variability than outliers at a given X-ray luminosity when the compact jet turns on. This trend is consistent with the internal shock model and can be important for the understanding of the presence of tracks in the radio/X-ray luminosity relation. We also observed that the total and the QPO rms amplitudes increase together during the earlier part of the outburst decay, but after the compact jet turns, either the QPO disappears or its rms amplitude decreases significantly while the total rms amplitudes remain high. We discuss these results with a scenario including a variable corona and a non-variable disk with a mechanism for the QPO separate from the mechanism that creates broad components. Finally, we evaluated the timing predictions of the magnetically dominated accretion flow model that can explain the presence of tracks in the radio/X-ray luminosity relation.

  8. Coding completeness and quality of relative survival-related variables in the National Program of Cancer Registries Cancer Surveillance System, 1995-2008.

    PubMed

    Wilson, Reda J; O'Neil, M E; Ntekop, E; Zhang, Kevin; Ren, Y

    2014-01-01

    Calculating accurate estimates of cancer survival is important for various analyses of cancer patient care and prognosis. Current US survival rates are estimated based on data from the National Cancer Institute's (NCI's) Surveillance, Epidemiology, and End RESULTS (SEER) program, covering approximately 28 percent of the US population. The National Program of Cancer Registries (NPCR) covers about 96 percent of the US population. Using a population-based database with greater US population coverage to calculate survival rates at the national, state, and regional levels can further enhance the effective monitoring of cancer patient care and prognosis in the United States. The first step is to establish the coding completeness and coding quality of the NPCR data needed for calculating survival rates and conducting related validation analyses. Using data from the NPCR-Cancer Surveillance System (CSS) from 1995 through 2008, we assessed coding completeness and quality on 26 data elements that are needed to calculate cancer relative survival estimates and conduct related analyses. Data elements evaluated consisted of demographic, follow-up, prognostic, and cancer identification variables. Analyses were performed showing trends of these variables by diagnostic year, state of residence at diagnosis, and cancer site. Mean overall percent coding completeness by each NPCR central cancer registry averaged across all data elements and diagnosis years ranged from 92.3 percent to 100 percent. RESULTS showing the mean percent coding completeness for the relative survival-related variables in NPCR data are presented. All data elements but 1 have a mean coding completeness greater than 90 percent as was the mean completeness by data item group type. Statistically significant differences in coding completeness were found in the ICD revision number, cause of death, vital status, and date of last contact variables when comparing diagnosis years. The majority of data items had a coding

  9. Rorschach variables and Big Five scales as predictors of military training completion: a replication study of the selection of candidates to the naval special forces in Norway.

    PubMed

    Hartmann, Ellen; Grønnerød, Cato

    2009-05-01

    We tested 140 male candidates at the Naval Special Forces (NFS) of Norway on the Rorschach (Exner, 2003; Rorschach, 1921/1942) and the Norwegian version of the Big Five personality dimensions (Engvik & Føllesdal, 2005). Rorschach variables significantly correlated with training completion (effect sizes of r(e) = .14-.25), whereas none of the Big Five factors or facets did. The combination of Rorschach and Big Five variables framed in the illusory mental health concept provided strong predictive ability. Testing under stress produced slightly higher predictive validity coefficients between the Rorschach variables and pass-fail than under calm testing. The findings support the results of Hartmann, Sunde, Kristensen, and Martinussen (2003), indicating that Rorschach variables and indications of good mental health may be valid predictors of NFS training.

  10. 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.

  11. The Complete Mitochondrial Genomes of Six Heterodont Bivalves (Tellinoidea and Solenoidea): Variable Gene Arrangements and Phylogenetic Implications

    PubMed Central

    Yuan, Yang; Li, Qi; Yu, Hong; Kong, Lingfeng

    2012-01-01

    Background Taxonomy and phylogeny of subclass Heterodonta including Tellinoidea are long-debated issues and a complete agreement has not been reached yet. Mitochondrial (mt) genomes have been proved to be a powerful tool in resolving phylogenetic relationship. However, to date, only ten complete mitochondrial genomes of Heterodonta, which is by far the most diverse major group of Bivalvia, have been determined. In this paper, we newly sequenced the complete mt genomes of six species belonging to Heterodonta in order to resolve some problematical relationships among this subclass. Principal Findings The complete mt genomes of six species vary in size from 16,352 bp to 18,182. Hairpin-like secondary structures are found in the largest non-coding regions of six freshly sequenced mt genomes, five of which contain tandem repeats. It is noteworthy that two species belonging to the same genus show different gene arrangements with three translocations. The phylogenetic analysis of Heterodonta indicates that Sinonovacula constricta, distant from the Solecurtidae belonging to Tellinoidea, is as a sister group with Solen grandis of family Solenidae. Besides, all five species of Tellinoidea cluster together, while Sanguinolaria diphos has closer relationship with Solecurtus divaricatus, Moerella iridescens and Semele scaba rather than with Sanguinolaria olivacea. Conclusions/Significance By comparative study of gene order rearrangements and phylogenetic relationships of the five species belonging to Tellinoidea, our results support that comparisons of mt gene order rearrangements, to some extent, are a useful tool for phylogenetic studies. Based on phylogenetic analyses of multiple protein-coding genes, we prefer classifying the genus Sinonovacula within the superfamily Solenoidea and not the superfamily Tellinoidea. Besides, both gene order and sequence data agree that Sanguinolaria (Psammobiidae) is not monophyletic. Nevertheless, more studies based on more mt genomes via

  12. 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.

  13. 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.

  14. 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

  15. Improving the Quality of Oral and Maxillofacial Surgical Notes in an Indian Public Sector Hospital in Accordance with the Royal College of Surgeons Guidelines: A Completed Audit Loop Study.

    PubMed

    Krishnan, B; Prasad, G Arun; Madhan, B

    2016-09-01

    Proper and adequate documentation in operation notes is a basic tool of clinical practice with medical and legal implications. An audit was done to ascertain if oral and maxillofacial surgery operative notes in an Indian public sector hospital adhered to the guidelines published by the Royal College of Surgeons England. Fifty randomly selected operative notes were evaluated against the guidelines by RCS England with regards to the essential generic components of an operation note. Additional criteria relevant to oral and Maxillofacial Surgery were also evaluated. Changes were introduced in the form of Oral and Maxillofacial Surgery specific consent forms, diagram sheets and a computerized operation note proforma containing all essential and additional criteria along with prefilled template of operative findings. Re-audit of 50 randomly selected operation notes was performed after a 6 month period. In the 1st audit cycle, excellent documentation ranging from 94 to 100 % was seen in 9 essential criteria. Unsatisfactory documentation was observed in criteria like assistant name, date of surgery. Most consent forms contained abbreviations and some did not provide all details. Additional criteria specific to Oral and Maxillofacial Surgery scored poorly. In the 2nd Audit for loop completion, excellent documentation was seen in almost all essential and additional criteria. Mean percentage of data point inclusion improved from 84.6 to 98.4 % (0.001< P value <0.005). The use of abbreviations was seen in only 6 notes. Regular audits are now considered a mandatory quality improvement process that seeks to improve patient care and outcomes. To the best of our knowledge, this is the first completed audit on operation notes documentation in Oral and Maxillofacial Surgery from India. The introduction of a computerized operation note proforma showed excellent improvement in operation note documentation. Surgeons can follow the RCS guidelines to ensure standardization of

  16. Stretched Loops

    NASA Image and Video Library

    2017-03-16

    When an active region rotated over to the edge of the sun, it presented us with a nice profile view of its elongated loops stretching and swaying above it (Mar. 8-9, 2017). These loops are actually charged particles (made visible in extreme ultraviolet light) swirling along the magnetic field lines of the active region. The video covers about 30 hours of activity. Also of note is a darker twisting mass of plasma to the left of the active region being pulled and spun about by magnetic forces. Video is available at http://photojournal.jpl.nasa.gov/catalog/PIA21562

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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

  4. 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.

  5. 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

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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

  11. Extensive size polymorphism of the human keratin 10 chain resides in the C-terminal V2 subdomain due to variable numbers and sizes of glycine loops

    SciTech Connect

    Korge, B.P.; Gan, Songqing; Steinert, P.M. ); McBride, O.W. ); Mischke, D. )

    1992-02-01

    Existing data suggest that the human keratin 10 intermediate filament protein is polymorphic in amino acid sequence and in size. To precisely define the nature of the polymorphism, the authors have used PCR amplification and sequence analyses on DNA from several individuals including five with documented size variations of the keratin 10 protein. They found no variation in the N-terminal or rod domain sequences. However, they observed many variations in the V2 subdomain near the C terminus in glycine-rich sequences with a variation of as much as 114 base pairs (38 amino acids), but all individuals had either one or two variants. The results show that (1) the keratin 10 system is far more polymorphic than previously realized, (2) the polymorphism is restricted to insertions and deletions of the glycine-rich quasipeptide repeats that form the glycine-loop motif in the C-terminal domain, (3) the polymorphism can be accounted for by simple allelic variations that segregate by normal Mendelian mechanisms, and (4) the differently sized PCR products most likely represent different alleles of a single-copy gene per haploid genome.

  12. Extensive size polymorphism of the human keratin 10 chain resides in the C-terminal V2 subdomain due to variable numbers and sizes of glycine loops.

    PubMed Central

    Korge, B P; Gan, S Q; McBride, O W; Mischke, D; Steinert, P M

    1992-01-01

    Existing data suggest that the human keratin 10 intermediate filament protein is polymorphic in amino acid sequence and in size. To precisely define the nature of the polymorphism, we have used PCR amplification and sequence analyses on DNA from several individuals including five with documented size variations of the keratin 10 protein. We found no variation in the N-terminal or rod domain sequences. However, we observed many variations in the V2 subdomain near the C terminus in glycine-rich sequences with a variation of as much as 114 base pairs (38 amino acids), but all individuals had either one or two variants. Our results show that (i) the keratin 10 system is far more polymorphic than previously realized, (ii) the polymorphism is restricted to insertions and deletions of the glycine-rich quasipeptide repeats that form the glycine-loop motif in the C-terminal domain, (iii) the polymorphism can be accounted for by simple allelic variations that segregate by normal Mendelian mechanisms, and (iv) the differently sized PCR products most likely represent different alleles of a single-copy gene per haploid genome. Images PMID:1371013

  13. 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.

  14. 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.

  15. 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)

  16. 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)

  17. A Novel Real-Time Path Servo Control of a Hardware-in-the-Loop for a Large-Stroke Asymmetric Rod-Less Pneumatic System under Variable Loads

    PubMed Central

    Lin, Hao-Ting

    2017-01-01

    This project aims to develop a novel large stroke asymmetric pneumatic servo system of a hardware-in-the-loop for path tracking control under variable loads based on the MATLAB Simulink real-time system. High pressure compressed air provided by the air compressor is utilized for the pneumatic proportional servo valve to drive the large stroke asymmetric rod-less pneumatic actuator. Due to the pressure differences between two chambers, the pneumatic actuator will operate. The highly nonlinear mathematical models of the large stroke asymmetric pneumatic system were analyzed and developed. The functional approximation technique based on the sliding mode controller (FASC) is developed as a controller to solve the uncertain time-varying nonlinear system. The MATLAB Simulink real-time system was a main control unit of a hardware-in-the-loop system proposed to establish driver blocks for analog and digital I/O, a linear encoder, a CPU and a large stroke asymmetric pneumatic rod-less system. By the position sensor, the position signals of the cylinder will be measured immediately. The measured signals will be viewed as the feedback signals of the pneumatic servo system for the study of real-time positioning control and path tracking control. Finally, real-time control of a large stroke asymmetric pneumatic servo system with measuring system, a large stroke asymmetric pneumatic servo system, data acquisition system and the control strategy software will be implemented. Thus, upgrading the high position precision and the trajectory tracking performance of the large stroke asymmetric pneumatic servo system will be realized to promote the high position precision and path tracking capability. Experimental results show that fifth order paths in various strokes and the sine wave path are successfully implemented in the test rig. Also, results of variable loads under the different angle were implemented experimentally. PMID:28587220

  18. A Novel Real-Time Path Servo Control of a Hardware-in-the-Loop for a Large-Stroke Asymmetric Rod-Less Pneumatic System under Variable Loads.

    PubMed

    Lin, Hao-Ting

    2017-06-04

    This project aims to develop a novel large stroke asymmetric pneumatic servo system of a hardware-in-the-loop for path tracking control under variable loads based on the MATLAB Simulink real-time system. High pressure compressed air provided by the air compressor is utilized for the pneumatic proportional servo valve to drive the large stroke asymmetric rod-less pneumatic actuator. Due to the pressure differences between two chambers, the pneumatic actuator will operate. The highly nonlinear mathematical models of the large stroke asymmetric pneumatic system were analyzed and developed. The functional approximation technique based on the sliding mode controller (FASC) is developed as a controller to solve the uncertain time-varying nonlinear system. The MATLAB Simulink real-time system was a main control unit of a hardware-in-the-loop system proposed to establish driver blocks for analog and digital I/O, a linear encoder, a CPU and a large stroke asymmetric pneumatic rod-less system. By the position sensor, the position signals of the cylinder will be measured immediately. The measured signals will be viewed as the feedback signals of the pneumatic servo system for the study of real-time positioning control and path tracking control. Finally, real-time control of a large stroke asymmetric pneumatic servo system with measuring system, a large stroke asymmetric pneumatic servo system, data acquisition system and the control strategy software will be implemented. Thus, upgrading the high position precision and the trajectory tracking performance of the large stroke asymmetric pneumatic servo system will be realized to promote the high position precision and path tracking capability. Experimental results show that fifth order paths in various strokes and the sine wave path are successfully implemented in the test rig. Also, results of variable loads under the different angle were implemented experimentally.

  19. 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.

  20. Polyakov loop modeling for hot QCD

    NASA Astrophysics Data System (ADS)

    Fukushima, Kenji; Skokov, Vladimir

    2017-09-01

    We review theoretical aspects of quantum chromodynamics (QCD) at finite temperature. The most important physical variable to characterize hot QCD is the Polyakov loop, which is an approximate order parameter for quark deconfinement in a hot gluonic medium. Additionally to its role as an order parameter, the Polyakov loop has rich physical contents in both perturbative and non-perturbative sectors. This review covers a wide range of subjects associated with the Polyakov loop from topological defects in hot QCD to model building with coupling to the Polyakov loop.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. Highly Efficient Modeling of Dynamic Coronal Loops

    NASA Astrophysics Data System (ADS)

    Klimchuk, J. A.; Patsourakos, S.; Cargill, P. J.

    2005-05-01

    It now seems clear that many coronal loops, especially those observed by TRACE and EIT, are inherently dynamic and composed of large numbers of impulsively-heated strands. Modeling these loops in full detail is extremely challenging, and modeling entire active regions or the whole Sun is completely out of the question unless approximate techniques are used. We have developed a simplified set of equations that is remarkably accurate at describing the evolution of the thermodynamic variables (T, P, n, v) averaged along the magnetic field of an individual strand. The equations can be solved ten thousand times more quickly than the full 1D hydro equations. This "0D" model relaxes two key assumptions of Cargill's (1994) nanoflare model: (1) the heating can have any time-dependent profile and need not be instantaneous; and (2) thermal conduction cooling and radiation cooling occur together at all times, in varying proportions. We here describe the essential features of the model and show examples of how well it works.

  7. 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

  8. 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.

  9. Blind Loop Syndrome

    MedlinePlus

    ... breeding ground for bacteria. The bacteria may produce toxins as well as block the absorption of nutrients. The greater the length of small bowel involved in the blind loop, the greater the chance of bacterial overgrowth. What triggers blind loop syndrome? Blind loop ...

  10. 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.

  11. 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.

  12. 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.

  13. Active Region Loop Models and Observations

    NASA Astrophysics Data System (ADS)

    Landi, E.; Landini, M.

    2004-01-01

    The analysis of broad band images from EIT and TRACE and spectra from SUMER and CDS have triggered a heated debate on 1) whether the loops are isothermal for most of their length 2) whether they are multithermal across their section and 3) what is the shape of their heating function. Our work describes a detailed comparison between SOHO-CDS observations of an active region loop with a standard RTV-like loop model developed assuming a temperature-independent heating function in the energy balance equation and a variable loop cross-section. Observations of an active region loop recorded by CDS have been analyzed. Additional data from EIT MDI and Yohkoh-SXT have been considered. Electron density temperature and pressure along the selected loop structure have been measured by means of line ratio techniques and an emission measure analysis. Comparison with CDS data has shown that 1) the RTV-like model is not able to reproduce the observations 2) the loop is isothermal along most of its length 3) the loop is isothermal across its section.

  14. 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.

  15. 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

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. Comparison of Physiological and Psychological Relaxation Using Measurements of Heart Rate Variability, Prefrontal Cortex Activity, and Subjective Indexes after Completing Tasks with and without Foliage Plants.

    PubMed

    Park, Sin-Ae; Song, Chorong; Oh, Yun-Ah; Miyazaki, Yoshifumi; Son, Ki-Cheol

    2017-09-20

    The objective of this study was to compare physiological and psychological relaxation by assessing heart rate variability (HRV), prefrontal cortex activity, and subjective indexes while subjects performed a task with and without foliage plants. In a crossover experimental design, 24 university students performed a task transferring pots with and without a foliage plant for 3 min. HRV and oxyhemoglobin (oxy-Hb) concentration in the prefrontal cortex were continuously measured. Immediately thereafter, subjective evaluation of emotions was performed using a modified semantic differential (SD) method and a profile of mood state questionnaire (POMS). Results showed that the natural logarithmic (ln) ratio of low frequency/high frequency, as an estimate of sympathetic nerve activity, was significantly lower while performing the task with foliage plants for the average 3 min measurement interval. Oxy-Hb concentration in the left prefrontal cortex showed a tendency to decrease in the 2-3 min interval in the task with foliage plants compared to the task without plants. Moreover, significant psychological relaxation according to POMS score and SD was demonstrated when the task involved foliage plants. In conclusion, the task involving foliage plants led to more physiological and psychological relaxation compared with the task without foliage plants.

  2. On vanishing two loop cosmological constants in nonsupersymmetric strings

    SciTech Connect

    Kachru, Shamit; Silverstein, Eva

    1998-10-16

    It has recently been suggested that in certain special nonsupersymmetric type II string compactifications, at least the first two perturbative contributions to the cosmological constant {Lambda} vanish. Support for perturbative vanishing beyond 1-loop (as well as evidence for the absence of some nonperturbative contributions) has come from duality arguments. There was also a direct 2-loop computation which was incomplete; in this note we explain the deficiency of the previous 2-loop calculation and discuss the complete 2-loop computation in two different models. The corrected analysis yields a vanishing 2-loop contribution to {Lambda} in these models.

  3. 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.

  4. Two-loop polygon Wilson loops in Script N = 4 SYM

    NASA Astrophysics Data System (ADS)

    Anastasiou, C.; Brandhuber, A.; Heslop, P.; Khoze, V. V.; Spence, B.; Travaglini, G.

    2009-05-01

    We compute for the first time the two-loop corrections to arbitrary n-gon lightlike Wilson loops in Script N = 4 supersymmetric Yang-Mills theory, using efficient numerical methods. The calculation is motivated by the remarkable agreement between the finite part of planar six-point MHV amplitudes and hexagon Wilson loops which has been observed at two loops. At n = 6 we confirm that the ABDK/BDS ansatz must be corrected by adding a remainder function, which depends only on conformally invariant ratios of kinematic variables. We numerically compute remainder functions for n = 7,8 and verify dual conformal invariance. Furthermore, we study simple and multiple collinear limits of the Wilson loop remainder functions and demonstrate that they have precisely the form required by the collinear factorisation of the corresponding two-loop n-point amplitudes. The number of distinct diagram topologies contributing to the n-gon Wilson loops does not increase with n, and there is a fixed number of ``master integrals", which we have computed. Thus we have essentially computed general polygon Wilson loops, and if the correspondence with amplitudes continues to hold, all planar n-point two-loop MHV amplitudes in the Script N = 4 theory.

  5. Fermions in hybrid loop quantum cosmology

    NASA Astrophysics Data System (ADS)

    Elizaga Navascués, Beatriz; Mena Marugán, Guillermo A.; Martín-Benito, Mercedes

    2017-08-01

    This work pioneers the quantization of primordial fermion perturbations in hybrid loop quantum cosmology (LQC). We consider a Dirac field coupled to a spatially flat, homogeneous, and isotropic cosmology, sourced by a scalar inflaton, and treat the Dirac field as a perturbation. We describe the inhomogeneities of this field in terms of creation and annihilation variables, chosen to admit a unitary evolution if the Dirac fermion were treated as a test field. Considering instead the full system, we truncate its action at quadratic perturbative order and construct a canonical formulation. In particular this implies that, in the global Hamiltonian constraint of the model, the contribution of the homogeneous sector is corrected with a quadratic perturbative term. We then adopt the hybrid LQC approach to quantize the full model, combining the loop representation of the homogeneous geometry with the Fock quantization of the inhomogeneities. We assume a Born-Oppenheimer ansatz for physical states and show how to obtain a Schrödinger equation for the quantum evolution of the perturbations, where the role of time is played by the homogeneous inflaton. We prove that the resulting quantum evolution of the Dirac field is indeed unitary, despite the fact that the underlying homogeneous geometry has been quantized as well. Remarkably, in such evolution, the fermion field couples to an infinite sequence of quantum moments of the homogeneous geometry. Moreover, the evolved Fock vacuum of our fermion perturbations is shown to be an exact solution of the Schrödinger equation. Finally, we discuss in detail the quantum backreaction that the fermion field introduces in the global Hamiltonian constraint. For completeness, our quantum study includes since the beginning (gauge-invariant) scalar and tensor perturbations, that were studied in previous works.

  6. Testing loop quantum cosmology

    NASA Astrophysics Data System (ADS)

    Wilson-Ewing, Edward

    2017-03-01

    Loop quantum cosmology predicts that quantum gravity effects resolve the big-bang singularity and replace it by a cosmic bounce. Furthermore, loop quantum cosmology can also modify the form of primordial cosmological perturbations, for example by reducing power at large scales in inflationary models or by suppressing the tensor-to-scalar ratio in the matter bounce scenario; these two effects are potential observational tests for loop quantum cosmology. In this article, I review these predictions and others, and also briefly discuss three open problems in loop quantum cosmology: its relation to loop quantum gravity, the trans-Planckian problem, and a possible transition from a Lorentzian to a Euclidean space-time around the bounce point.

  7. 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

  8. 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.

  9. 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.

  10. Thermal power loops

    NASA Technical Reports Server (NTRS)

    Gottschlich, Joseph M.; Richter, Robert

    1991-01-01

    The concept of a thermal power loop (TPL) to transport thermal power over relatively large distances is presented as an alternative to heat pipes and their derivatives. The TPL is compared to heat pipes, and capillary pumped loops with respect to size, weight, conservation of thermal potential, start-up, and 1-g testing capability. Test results from a proof of feasibility demonstrator at the NASA JPL are discussed. This analysis demonstrates that the development of specific thermal power loops will result in substantial weight and cost savings for many spacecraft.

  11. Large lithium loop experience

    SciTech Connect

    Kolowith, R.; Owen, T.J.; Berg, J.D.; Atwood, J.M.

    1981-10-01

    An engineering design and operating experience of a large, isothermal, lithium-coolant test loop are presented. This liquid metal coolant loop is called the Experimental Lithium System (ELS) and has operated safely and reliably for over 6500 hours through September 1981. The loop is used for full-scale testing of components for the Fusion Materials Irradiation Test (FMIT) Facility. Main system parameters include coolant temperatures to 430/sup 0/C and flow to 0.038 m/sup 3//s (600 gal/min). Performance of the main pump, vacuum system, and control system is discussed. Unique test capabilities of the ELS are also discussed.

  12. 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.

  13. 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.

  14. 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.

  15. Quark and Gluon Form Factors to Three Loops

    SciTech Connect

    Baikov, P. A.; Smirnov, V. A.; Chetyrkin, K. G.; Smirnov, A. V.; Steinhauser, M.

    2009-05-29

    We compute the form factors of the photon-quark-anti-quark vertex and the effective vertex of a Higgs-boson and two gluons to three-loop order within massless perturbative quantum chromodynamics. These results provide building blocks for many third-order cross sections. Furthermore, this is the first calculation of complete three-loop vertex corrections.

  16. Dynamic Loops in Profile

    NASA Image and Video Library

    2017-03-28

    As an active region rotated into view, NASA Solar Dynamics Observatory was able to observe well-defined magnetic loops gyrating above the sun between Mar, 23-24, 2017. These loops appear because charged particles spinning along the magnetic field lines above this active region are made visible in this wavelength of extreme ultraviolet light. The video clip covers about a day and a half of activity. Movies are available at https://photojournal.jpl.nasa.gov/catalog/PIA21583

  17. 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.

  18. 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.

  19. 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.

  20. Wald entropy formula and loop quantum gravity

    NASA Astrophysics Data System (ADS)

    Bodendorfer, N.; Neiman, Y.

    2014-10-01

    We outline how the Wald entropy formula naturally arises in loop quantum gravity based on recently introduced dimension-independent connection variables. The key observation is that in a loop quantization of a generalized gravity theory, the analog of the area operator turns out to measure, morally speaking, the Wald entropy rather than the area. We discuss the explicit example of (higher-dimensional) Lanczos-Lovelock gravity and comment on recent work on finding the correct numerical prefactor of the entropy by comparing it to a semiclassical effective action.

  1. 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.

  2. Classical Physics and Quantum Loops

    SciTech Connect

    Barry R. Holstein; John F. Donoghue

    2004-05-01

    The standard picture of the loop expansion associates a factor of h-bar with each loop, suggesting that the tree diagrams are to be associated with classical physics, while loop effects are quantum mechanical in nature. We discuss examples wherein classical effects arise from loop contributions and display the relationship between the classical terms and the long range effects of massless particles.

  3. Shape of Cosmic String Loops

    NASA Astrophysics Data System (ADS)

    Copi, Craig J.; Vachaspati, Tanmay

    2010-11-01

    Complicated cosmic string loops will fragment until they reach simple, non-intersecting ("stable") configurations. Through extensive numerical study we characterize these attractor loop shapes including their length, velocity, kink, and cusp distributions. We find that an initial loop containing M harmonic modes will, on average, split into 3M stable loops. These stable loops are approximately described by the degenerate kinky loop, which is planar and rectangular, independently of the number of modes on the initial loop. This is confirmed by an analytic construction of a stable family of perturbed degenerate kinky loops. The average stable loop is also found to have a 40% chance of containing a cusp. We examine the properties of stable loops of different lengths and find only slight variation. Finally we develop a new analytic scheme to explicitly solve the string constraint equations.

  4. Shape of cosmic string loops

    NASA Astrophysics Data System (ADS)

    Copi, Craig J.; Vachaspati, Tanmay

    2011-01-01

    Complicated cosmic string loops will fragment until they reach simple, nonintersecting (“stable”) configurations. Through extensive numerical study we characterize these attractor loop shapes including their length, velocity, kink, and cusp distributions. We find that an initial loop containing M harmonic modes will, on average, split into 3M stable loops. These stable loops are approximately described by the degenerate kinky loop, which is planar and rectangular, independently of the number of modes on the initial loop. This is confirmed by an analytic construction of a stable family of perturbed degenerate kinky loops. The average stable loop is also found to have a 40% chance of containing a cusp. We examine the properties of stable loops of different lengths and find only slight variation. Finally we develop a new analytic scheme to explicitly solve the string constraint equations.

  5. 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

  6. 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

  7. Control loop noise rejection using fuzzy logic.

    PubMed

    Hay, Glen; Svrcek, William; Ross, Timothy; Young, Brent

    2005-10-01

    This paper describes an application of fuzzy logic to noise rejection in a control loop. This new use of fuzzy logic solves the problem of sluggish control loop response when using a set-point range to stop constant valve chattering due to noise in the output signal being sent to a control valve. Multiple related variables and a general understanding of their inter-relationship must be available for this method to be successfully applied. An overview of the specific fuzzy logic method used for this application is presented along with guidelines for the practical application. In addition, this paper includes results from the successful implementation of fuzzy logic to a control loop on a pilot plant distillation column.

  8. Open Loop Active Control of Combustion Dynamics on a Gas Turbine Engine

    SciTech Connect

    Richards, G.A.; Thornton, J.D.; Robey, E.H.; Arellano, Leonel

    2007-01-01

    Combustion dynamics is a prominent problem in the design and operation of low-emission gas turbine engines. Even modest changes in fuel composition or operating conditions can lead to damaging vibrations in a combustor that was otherwise stable. For this reason, active control has been sought to stabilize combustors that must accommodate fuel variability, new operating conditions, etc. Active control of combustion dynamics has been demonstrated in a number of laboratories, single-nozzle test combustors, and even on a fielded engine. In most of these tests, active control was implemented with closed-loop feedback between the observed pressure signal and the phase and gain of imposed fuel perturbations. In contrast, a number of recent papers have shown that open-loop fuel perturbations can disrupt the feedback between acoustics and heat release that drives the oscillation. Compared to the closed-loop case, this approach has some advantages because it may not require high-fidelity fuel actuators, and could be easier to implement. This paper reports experimental tests of open-loop fuel perturbations to control combustion dynamics in a complete gas turbine engine. Results demonstrate the technique was very successful on the test engine and had minimal effect on pollutant emissions.

  9. 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

  10. Loop quantum gravity

    NASA Astrophysics Data System (ADS)

    Chiou, Dah-Wei

    2015-12-01

    This paper presents an "in-a-nutshell" yet self-contained introductory review on loop quantum gravity (LQG) — a background-independent, nonperturbative approach to a consistent quantum theory of gravity. Instead of rigorous and systematic derivations, it aims to provide a general picture of LQG, placing emphasis on the fundamental ideas and their significance. The canonical formulation of LQG, as the central topic of the paper, is presented in a logically orderly fashion with moderate details, while the spin foam theory, black hole thermodynamics, and loop quantum cosmology are covered briefly. Current directions and open issues are also summarized.

  11. 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.

  12. Observations and Modeling of Solar Coronal Loops

    NASA Astrophysics Data System (ADS)

    Klimchuk, J.

    Coronal loops are often described as the fundamental building blocks of solar and stellar coronae. Clearly, therefore, a comprehensive understanding of coronae requires an explanation of the nature and origin of these loops, including the mechanism of their heating. Certain general aspects of coronal loops are reasonably well understood. For example, we know that the plasma is structured by the magnetic field and that strongly heated flux tubes tend to be hotter and denser than weakly heated flux tubes. Some observations suggest that loops are in quasi-static equilibrium, and scaling laws have been used to describe the relationships among physical variables and to test competing theories of coronal heating. Other observations raise serious doubts about whether the quasi-static description is valid. At this point, we cannot say with any certainty whether loops are isothermal or multithermal (i.e., monolithic structures or collections of unresolved strands) or whether they are heated steadily or in a highly episodic fashion (e.g., by nanoflares). This talk will address what we can learn about these important questions from a combination of observations and theoretical modeling.

  13. 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

  14. 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.

  15. 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]).

  16. Assessing catchment connectivity using hysteretic loops

    NASA Astrophysics Data System (ADS)

    Davis, Jason; Masselink, Rens; Goni, Mikel; Gimenez, Rafael; Casali, Javier; Seeger, Manuel; Keesstra, Saskia

    2017-04-01

    texture topsoil), climate (humid sub Mediterranean) and land use (80-90% cultivated with winter grain crops). Ozkotz principal (ca.1,700 ha) is covered with forest and pasture (cattle-breeding); while Oskotz woodland (ca. 500 ha), a sub-watershed of the Oskotz principal, is almost completely covered with forest. The predominant climate in the Oskotz catchments sub-Atlantic. Furthermore, antecedent conditions and event characteristics were analysed. The loops were compared quantitatively and qualitatively between catchments for similar events and within the catchments for events with different characteristics. In this study, several measures to objectively classify hysteresis loops in an automated way were developed. These were consecutively used to classify several hundreds of loops from several agricultural catchments in Northern Spain. These loop characteristics were compared to event specific characteristics such as antecedent precipitation, time of year, and precipitation intensity, duration and total. The combination of hysteresis loops and variables influencing connectivity can then tell something about the sources of sediments for different events and catchments. References Baartman, J.E.M., Masselink, R.H., Keesstra, S.D., Temme, A.J.A.M., 2013. Linking landscape morphological complexity and sediment connectivity. Earth Surface Processes and Landforms 38: 1457-1471. Masselink RJH, Heckmann T, Temme AJAM, Anders NS, Gooren HPA, Keesstra SD. 2016. A network theory approach for a better understanding of overland flow connectivity. Hydrological Processes. DOI: 10.1002/hyp.10993 Masselink, R.J.H., Keesstra, S.D., Temme, A.J.A.M., Seeger, M., Giménez, R., Casalí, J., 2016. Modelling Discharge and Sediment Yield at Catchment Scale Using Connectivity Components. Land Degradation and Development 27: 933-945, DOI: 10.1002/ldr.2512 Mekonnen, M., Keesstra, S.D., Baartman, J.E.M., Stroosnijder, L., Maroulis, J., Reducing sediment connectivity through man-made and natural

  17. Mashup the OODA Loop

    DTIC Science & Technology

    2008-06-01

    MTR070365 MITRE TECHNICAL REPORT Mashup the OODA Loop June 2008 Jeffrey E. Heier-E305 C2C Center – MITRE New Jersey Sponsor: Sponsor Name...ES) The MITRE Corporation, C2C Center,260 Industrial Way West,Eatontown,NJ,07724 8. PERFORMING ORGANIZATION REPORT NUMBER 9. SPONSORING/MONITORING

  18. 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)…

  19. 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)…

  20. Reversible hysteresis loop tuning

    NASA Astrophysics Data System (ADS)

    Berger, A.; Binek, Ch.; Margulies, D. T.; Moser, A.; Fullerton, E. E.

    2006-02-01

    We utilize antiferromagnetically coupled bilayer structures to magnetically tune hysteresis loop properties. Key element of this approach is the non-overlapping switching field distribution of the two magnetic layers that make up the system: a hard magnetic CoPtCrB layer (HL) and a soft magnetic CoCr layer (SL). Both layers are coupled antiferromagnetically through an only 0.6-nm-thick Ru interlayer. The non-overlapping switching field distribution allows the measurement of magnetization reversal in the SL at low fields while keeping the magnetization state of the HL unperturbed. Applying an appropriate high field or high field sequence changes the magnetic state of the HL, which then influences the SL magnetization reversal due to the interlayer coupling. In this way, the position and shape of the SL hysteresis loop can be changed or tuned in a fully reversible and highly effective manner. Here, we study specifically how the SL hysteresis loop characteristics change as we move the HL through an entire high field hysteresis loop sequence.

  1. Closing the Assessment Loop

    ERIC Educational Resources Information Center

    Banta, Trudy W.; Blaich, Charles

    2011-01-01

    Accreditors, speakers at assessment conferences, and campus leaders all decry the fact that too few faculty are closing the loop--that is, studying assessment findings to see what improvements might be suggested and taking the appropriate steps to make them. This is difficult enough with locally developed measures; adding the need to interpret…

  2. 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.

  3. 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.

  4. A New Coronal Loop Identification Method Based on Phase Congruency

    NASA Astrophysics Data System (ADS)

    Li, Hong-bo; Zhao, Ming-yu; Liu, Yu

    2017-07-01

    We have tried to apply the enhanced image by a phase congruency method to the identification of coronal loop structures, and proposed a new coronal loop identification method (simply called the PCB method) based on the enhanced image by the phase congruency method. On account of the smooth morphological variation in the direction along a coronal loop, the propelling direction of coronal loop identification is restricted in a small range for improving the identified result. Beyond that, inspired by the structural characteristics of coronal loops, we firstly suggest that both the variation of propelling direction in the identification process and the magnitude of phase congruency at the identified point are simultaneously taken as the criterion to terminate the identification. Finally, several coronal images are used for testing our coronal loop identification method, and the result indicates that the enhanced image by the phase congruency method is really suitable for the coronal loop identification, and the coronal loop structures identified by the PCB method have simultaneously a good completeness and a high accuracy, hence, the PCB method is a set of practical and feasible method of automated coronal loop identification.

  5. 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.

  6. Classical physics and quantum loops.

    PubMed

    Holstein, Barry R; Donoghue, John F

    2004-11-12

    The standard picture of the loop expansion associates a factor of variant Planck's over 2pi with each loop, suggesting that the tree diagrams are to be associated with classical physics, while loop effects are quantum mechanical in nature. We discuss counterexamples wherein classical effects arise from loop diagrams and display the relationship between the classical terms and the long range effects of massless particles.

  7. 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.

  8. 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.

  9. Numerical studies of the energy balance in coronal loops

    NASA Technical Reports Server (NTRS)

    Underwood, J. H.; Antiochos, S. K.; Vesecky, J. F.

    1981-01-01

    A numerical method is applied to treat the energy balance of quasi-static solar coronal loops, which have been observed to persist for periods much greater than the radiative cooling time. The quasi-static loop model employed takes into account gravity, density-, temperature- or position-dependent energy input, an accurate form of the radiative losses and variable loop cross-sectional area, under assumptions of energy input by coronal heating balanced by radiative and conductive losses, an optically thin plasma, energy conduction along the field lines only and hydrostatic equilibrium. Computations of an emission measure function for various distributions of the energy input and loop geometries are then presented which show that little information on the location of the energy input may be gained from spectral line intensity measurements integrated over a single loop.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. Cosmic string loop microlensing

    NASA Astrophysics Data System (ADS)

    Bloomfield, Jolyon K.; Chernoff, David F.

    2014-06-01

    Cosmic superstring loops within the galaxy microlens background point sources lying close to the observer-string line of sight. For suitable alignments, multiple paths coexist and the (achromatic) flux enhancement is a factor of two. We explore this unique type of lensing by numerically solving for geodesics that extend from source to observer as they pass near an oscillating string. We characterize the duration of the flux doubling and the scale of the image splitting. We probe and confirm the existence of a variety of fundamental effects predicted from previous analyses of the static infinite straight string: the deficit angle, the Kaiser-Stebbins effect, and the scale of the impact parameter required to produce microlensing. Our quantitative results for dynamical loops vary by O(1) factors with respect to estimates based on infinite straight strings for a given impact parameter. A number of new features are identified in the computed microlensing solutions. Our results suggest that optical microlensing can offer a new and potentially powerful methodology for searches for superstring loop relics of the inflationary era.

  15. 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.

  16. 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.

  17. 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).

  18. Nonlinear model predictive control for chemical looping process

    DOEpatents

    Joshi, Abhinaya; Lei, Hao; Lou, Xinsheng

    2017-08-22

    A control system for optimizing a chemical looping ("CL") plant includes a reduced order mathematical model ("ROM") that is designed by eliminating mathematical terms that have minimal effect on the outcome. A non-linear optimizer provides various inputs to the ROM and monitors the outputs to determine the optimum inputs that are then provided to the CL plant. An estimator estimates the values of various internal state variables of the CL plant. The system has one structure adapted to control a CL plant that only provides pressure measurements in the CL loops A and B, a second structure adapted to a CL plant that provides pressure measurements and solid levels in both loops A, and B, and a third structure adapted to control a CL plant that provides full information on internal state variables. A final structure provides a neural network NMPC controller to control operation of loops A and B.

  19. Coronal Loops: Isothermal or Multithermal?

    NASA Astrophysics Data System (ADS)

    Kimble, Jason; Schmelz, J. T.; Nasraoui, K.; Cirtain, J. W.; Del Zanna, G.; DeLuca, E. E.; Mason, H. E.

    2007-05-01

    The coronal loop data used for this analysis were taken on 2003 January 17 at 14:24:45 UT by the Coronal Diagnostic Spectrometer (CDS) aboard the Solar and Heliospheric Observatory. We use the Chianti atomic physics data base and the hybrid coronal abundances to determine temperatures and densities for positions along several loops. The traditional method used to create our differential emission measure (DEM) curves has been forward folding, but we are now using both emission measure loci plots and DEM automatic inversion to support and confirm the original conclusions. In this poster, we will look specifically at the emission measure loci analysis of three loops visible in the CDS data set. We find different results for each of these loops. One of the loops seems to be composed of isothermal plasma with Log T = 5.8 MK. The temperature does not appear to change with position, from the footpoint to the loop leg. Unfortunately, the loop top is outside the CDS field of view. Each pixel examined in the second loop seems to require a multithermal DEM distribution. For the third loop, the temperature increases and the density appears to decrease with loop height, reminiscent of traditional hydrostatic loop models. Solar physics research at the University of Memphis is supported by NSF ATM-0402729 and NASA NNG05GE68G.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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

  7. Bright Loops at 171

    NASA Technical Reports Server (NTRS)

    2007-01-01

    STEREO was able to capture bright loops in exquisite detail as they were arcing above an active region (May 26, 2007) over an 18 hour period. What we are actually seeing are charged particles spinning along magnetic field lines that extend above the Sun's surface. Active regions are areas of intense magnetic activity and often the source of solar storms. In fact, the clip ends with a flourish in which a small coronal mass ejection (CME) blows out into space. This is from the STEREO Ahead spacecraft at the 171 Angstroms wavelength in extreme ultraviolet light.

  8. Bright Arcing Loops

    NASA Image and Video Library

    2016-06-27

    Several arcing loops rotated into view and swirled above an active region, which gave us a nice profile view of the action (June 26-27, 2016). The arcing plasma is tracing magnetic field lines extending out from the active region. Some darker matter also jiggled back and forth near the active region as well, pulled about by magnetic forces. At one point a lick of plasma pushed its way out from the region but quickly fell back into the sun. The images were taken in a wavelength of extreme ultraviolet light. Movies are also available at the Photojournal. http://photojournal.jpl.nasa.gov/catalog/PIA20882

  9. 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.

  10. Bright Loops at 171

    NASA Technical Reports Server (NTRS)

    2007-01-01

    STEREO was able to capture bright loops in exquisite detail as they were arcing above an active region (May 26, 2007) over an 18 hour period. What we are actually seeing are charged particles spinning along magnetic field lines that extend above the Sun's surface. Active regions are areas of intense magnetic activity and often the source of solar storms. In fact, the clip ends with a flourish in which a small coronal mass ejection (CME) blows out into space. This is from the STEREO Ahead spacecraft at the 171 Angstroms wavelength in extreme ultraviolet light.

  11. 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.

  12. 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

  13. 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

  14. 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.

  15. 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

  16. Accelerating the loop expansion

    SciTech Connect

    Ingermanson, R.

    1986-07-29

    This thesis introduces a new non-perturbative technique into quantum field theory. To illustrate the method, I analyze the much-studied phi/sup 4/ theory in two dimensions. As a prelude, I first show that the Hartree approximation is easy to obtain from the calculation of the one-loop effective potential by a simple modification of the propagator that does not affect the perturbative renormalization procedure. A further modification then susggests itself, which has the same nice property, and which automatically yields a convex effective potential. I then show that both of these modifications extend naturally to higher orders in the derivative expansion of the effective action and to higher orders in the loop-expansion. The net effect is to re-sum the perturbation series for the effective action as a systematic ''accelerated'' non-perturbative expansion. Each term in the accelerated expansion corresponds to an infinite number of terms in the original series. Each term can be computed explicitly, albeit numerically. Many numerical graphs of the various approximations to the first two terms in the derivative expansion are given. I discuss the reliability of the results and the problem of spontaneous symmetry-breaking, as well as some potential applications to more interesting field theories. 40 refs.

  17. 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.

  18. 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

  19. 2 π -flux loop semimetals

    NASA Astrophysics Data System (ADS)

    Li, Linhu; Chesi, Stefano; Yin, Chuanhao; Chen, Shu

    2017-08-01

    We introduce a model of 2 π -flux loop semimetals which holds nodal loops described by a winding number ν =2 . By adding some extra terms, this model can be transformed into a recently discovered Hopf-link semimetal, and the symmetries distinguishing these two types of semimetals are studied. We also propose a simpler physical implementation of 2 π -flux loops and of Hopf-link semimetals which only involves nearest-neighbor hoppings, although in the presence of spin-orbit interactions. Finally, we investigate the Floquet properties of the 2 π -flux loop, and find that such a loop may be driven into two separated π -flux loops or four Weyl points by light with circular polarization in certain directions.

  20. Robust closed-loop control of induction and maintenance of propofol anesthesia in children.

    PubMed

    West, Nicholas; Dumont, Guy A; van Heusden, Klaske; Petersen, Christian L; Khosravi, Sara; Soltesz, Kristian; Umedaly, Aryannah; Reimer, Eleanor; Ansermino, J Mark

    2013-08-01

    During closed-loop control, a drug infusion is continually adjusted according to a measure of clinical effect (e.g., an electroencephalographic depth of hypnosis (DoH) index). Inconsistency in population-derived pediatric pharmacokinetic/pharmacodynamic models and the large interpatient variability observed in children suggest a role for closed-loop control in optimizing the administration of intravenous anesthesia. To clinically evaluate a robustly tuned system for closed-loop control of the induction and maintenance of propofol anesthesia in children undergoing gastrointestinal endoscopy. One hundred and eight children, aged 6-17, ASA I-II, were enrolled. Prior to induction of anesthesia, NeuroSENSE™ sensors were applied to obtain the WAVCNS DoH index. An intravenous cannula was inserted and lidocaine (0.5 mg·kg(-1) ) administered. Remifentanil was administered as a bolus (0.5 μg·kg(-1) ), followed by continuous infusion (0.03 μg·kg(-1) ·min(-1) ). The propofol infusion was closed-loop controlled throughout induction and maintenance of anesthesia, using WAVCNS as feedback. Anesthesia was closed-loop controlled in 102 cases. The system achieved and maintained an adequate DoH without manual adjustment in 87/102 (85%) cases. Induction of anesthesia (to WAVCNS  ≤ 60) was completed in median 3.8 min (interquartile range (IQR) 3.1-5.0), culminating in a propofol effect-site concentration (Ce ) of median 3.5 μg·ml(-1) (IQR 2.7-4.5). During maintenance of anesthesia, WAVCNS was measured within 10 units of the target for median 89% (IQR 79-96) of the time. Spontaneous breathing required no manual intervention in 91/102 (89%) cases. A robust closed-loop system can provide effective propofol administration during induction and maintenance of anesthesia in children. Wide variation in the calculated Ce highlights the limitation of open-loop regimes based on pharmacokinetic/pharmacodynamic models. © 2013 John Wiley & Sons Ltd.

  1. 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

  2. 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

  3. Pathological complete response in patients with esophageal cancer after the trimodality approach: The association with baseline variables and survival-The University of Texas MD Anderson Cancer Center experience.

    PubMed

    Blum Murphy, Mariela; Xiao, Lianchum; Patel, Viren R; Maru, Dipen M; Correa, Arlene M; G Amlashi, Fatemeh; Liao, Zhongxing; Komaki, Ritsuko; Lin, Steven H; Skinner, Heath D; Vaporciyan, Ara; Walsh, Garrett L; Swisher, Stephen G; Sepesi, Boris; Lee, Jeffrey H; Bhutani, Manoop S; Weston, Brian; Hofstetter, Wayne L; Ajani, Jaffer A

    2017-09-08

    Reports are limited regarding clinical and pretreatment features that might predict a pathological complete response (pathCR) after treatment in patients with esophageal cancer (EC). This might allow patient selection for different strategies. This study examines the association of a pathCR with pretreatment variables, overall survival (OS), recurrence-free survival (RFS), and patterns of recurrence in a large cohort from a single institution. The baseline clinical features of 911 consecutive patients with EC who were treated with trimodality therapy from January 2000 to November 2013 were analyzed. A pathCR was defined as a surgical specimen with no residual carcinoma (primary or nodes). Logistic regressions were used to identify independent baseline features associated with a pathCR. We applied log-rank testing and Cox models to determine the association between a pathCR and the time-to-event outcomes (OS and RFS). Of 911 patients, 218 (23.9%) achieved a pathCR. The pathCR rate was 23.1% for adenocarcinoma and 32.2% for squamous cell carcinoma. A lower pathCR rate was observed for 1) older patients (>60 years), 2) patients with poorly differentiated tumors, 3) patients with signet ring cells (SRCs), and 4) patients with a higher T stage. Patients with a pathCR had longer OS and RFS than those without a pathCR (P = .0021 and P = .0011, respectively). Recurrences occurred more in non-pathCR patients. Distant metastases were the most common type of recurrence. PathCR patients developed brain metastases at a marginally higher rate than non-pathCR patients (P = .051). In this large cohort study, a pathCR is confirmed to be associated with better OS and RFS. The presence of a poorly differentiated tumor or SRCs reduces the likelihood of a pathCR. Future research should focus on molecular classifiers. Cancer 2017. © 2017 American Cancer Society. © 2017 American Cancer Society.

  4. 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.

  5. 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.

  6. 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.

  7. 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,…

  8. 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,…

  9. 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.

  10. 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.

  11. 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.

  12. 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

  13. Loop gravity string

    NASA Astrophysics Data System (ADS)

    Freidel, Laurent; Perez, Alejandro; Pranzetti, Daniele

    2017-05-01

    In this work we study canonical gravity in finite regions for which we introduce a generalization of the Gibbons-Hawking boundary term including the Immirzi parameter. We study the canonical formulation on a spacelike hypersurface with a boundary sphere and show how the presence of this term leads to an unprecedented type of degrees of freedom coming from the restoration of the gauge and diffeomorphism symmetry at the boundary. In the presence of a loop quantum gravity state, these boundary degrees of freedom localize along a set of punctures on the boundary sphere. We demonstrate that these degrees of freedom are effectively described by auxiliary strings with a three-dimensional internal target space attached to each puncture. We show that the string currents represent the local frame field, that the string angular momenta represent the area flux, and that the string stress tensor represents the two-dimensional metric on the boundary of the region of interest. Finally, we show that the commutators of these broken diffeomorphism charges of quantum geometry satisfy, at each puncture, a Virasoro algebra with central charge c =3 . This leads to a description of the boundary degrees of freedom in terms of a CFT structure with central charge proportional to the number of loop punctures. The boundary S U (2 ) gauge symmetry is recovered via the action of the U (1 )3 Kac-Moody generators (associated with the string current) in a way that is the exact analog of an infinite dimensional generalization of the Schwinger spin representation. We finally show that this symmetry is broken by the presence of background curvature.

  14. 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.

  15. ModLoop: automated modeling of loops in protein structures.

    PubMed

    Fiser, András; Sali, Andrej

    2003-12-12

    ModLoop is a web server for automated modeling of loops in protein structures. The input is the atomic coordinates of the protein structure in the Protein Data Bank format, and the specification of the starting and ending residues of one or more segments to be modeled, containing no more than 20 residues in total. The output is the coordinates of the non-hydrogen atoms in the modeled segments. A user provides the input to the server via a simple web interface, and receives the output by e-mail. The server relies on the loop modeling routine in MODELLER that predicts the loop conformations by satisfaction of spatial restraints, without relying on a database of known protein structures. For a rapid response, ModLoop runs on a cluster of Linux PC computers. The server is freely accessible to academic users at http://salilab.org/modloop

  16. The free-energy cost of interaction between DNA loops.

    PubMed

    Huang, Lifang; Liu, Peijiang; Yuan, Zhanjiang; Zhou, Tianshou; Yu, Jianshe

    2017-10-03

    From the viewpoint of thermodynamics, the formation of DNA loops and the interaction between them, which are all non-equilibrium processes, result in the change of free energy, affecting gene expression and further cell-to-cell variability as observed experimentally. However, how these processes dissipate free energy remains largely unclear. Here, by analyzing a mechanic model that maps three fundamental topologies of two interacting DNA loops into a 4-state model of gene transcription, we first show that a longer DNA loop needs more mean free energy consumption. Then, independent of the type of interacting two DNA loops (nested, side-by-side or alternating), the promotion between them always consumes less mean free energy whereas the suppression dissipates more mean free energy. More interestingly, we find that in contrast to the mechanism of direct looping between promoter and enhancer, the facilitated-tracking mechanism dissipates less mean free energy but enhances the mean mRNA expression, justifying the facilitated-tracking hypothesis, a long-standing debate in biology. Based on minimal energy principle, we thus speculate that organisms would utilize the mechanisms of loop-loop promotion and facilitated tracking to survive in complex environments. Our studies provide insights into the understanding of gene expression regulation mechanism from the view of energy consumption.

  17. A knowledge-driven approach for crystallographic protein model completion

    PubMed Central

    Joosten, Krista; Cohen, Serge X.; Emsley, Paul; Mooij, Wijnand; Lamzin, Victor S.; Perrakis, Anastassis

    2008-01-01

    One of the most cumbersome and time-demanding tasks in completing a protein model is building short missing regions or ‘loops’. A method is presented that uses structural and electron-density information to build the most likely conformations of such loops. Using the distribution of angles and dihedral angles in pentapeptides as the driving parameters, a set of possible conformations for the Cα backbone of loops was generated. The most likely candidate is then selected in a hierarchical manner: new and stronger restraints are added while the loop is built. The weight of the electron-density correlation relative to geometrical considerations is gradually increased until the most likely loop is selected on map correlation alone. To conclude, the loop is refined against the electron density in real space. This is started by using structural information to trace a set of models for the Cα backbone of the loop. Only in later steps of the algorithm is the electron-density correlation used as a criterion to select the loop(s). Thus, this method is more robust in low-density regions than an approach using density as a primary criterion. The algorithm is implemented in a loop-building program, Loopy, which can be used either alone or as part of an automatic building cycle. Loopy can build loops of up to 14 residues in length within a couple of minutes. The average root-mean-square deviation of the Cα atoms in the loops built during validation was less than 0.4 Å. When implemented in the context of automated model building in ARP/wARP, Loopy can increase the completeness of the built models. PMID:18391408

  18. 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.

  19. 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.

  20. RCD+: Fast loop modeling server.

    PubMed

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

    2016-07-08

    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. © The Author(s) 2016. Published by Oxford University Press on behalf of Nucleic Acids Research.

  1. 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

  2. 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.

  3. 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

  4. 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.

  5. 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.

  6. Dimensional assessment of continuous loop cortical suspension devices and clinical implications for intraoperative button flipping and intratunnel graft length.

    PubMed

    Turnbull, Travis Lee; LaPrade, Christopher M; Smith, Sean D; LaPrade, Robert F; Wijdicks, Coen A

    2015-09-01

    Continuous loop cortical suspension devices have been demonstrated to be more consistent and biomechanically superior compared to adjustable loop devices; however, continuous loop devices present unique challenges compared to adjustable loop devices, especially in short tunnel reconstruction applications. Specifically, adjustable loop devices have the advantage of a "one size fits all" approach, and the ability to tension these devices following button flipping allows for the intratunnel graft length to be maximized. Nevertheless, the reliability of continuous loop devices has sustained their widespread use. We hypothesized that continuous loop cortical suspension devices from different manufacturers would exhibit equivalent 15 mm loop lengths, as advertised. Loop length was measured using a tensile testing machine. Contrary to our hypothesis, continuous loop cortical suspension devices with equivalent advertised lengths exhibited different loop lengths (up to 27% discrepancy). Inconsistencies with regards to manufacturers' reported loop lengths for continuous loop devices could have serious clinical implications and additionally complicate technique transferal among devices. Consequently, the manufacturers' accurate and complete disclosure of the dimensions and specifications associated with each continuous loop device is critical. Furthermore, surgeon awareness of true loop length dimensions and inconsistencies among devices is needed to ensure optimal implantation and resultant clinical outcomes. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

  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. Stability of solar coronal loops

    NASA Astrophysics Data System (ADS)

    Goedbloed, J. P.

    1990-05-01

    The equations of magnetohydrodynamics do not contain an intrinsic length scale determining the size of phenomena. Hence, size only enters through the external geometrical properties of the configurations considered. This is one of the reasons why tokamaks and solar coronal loops may be considered as similar objects. The equations of MHD do not distinguish between the two. It is only the geometry and, hence, the boundary conditions that discriminate between them. Whereas for tokamaks toroidal periodicity and normal confinement provide the appropriate boundary conditions, for coronal loops line-tying at the photosphere and some prescription for the behavior across the ``edge'' of the loop determine the solutions. The latter is a more complicated problem and gives rise to even more complex dynamics than encountered in tokamaks. Here, we consider the influence of the two mentioned groups of boundary conditions for the problem of the stability and disruption of a solar coronal loop. We consider the stability properties of a single loop with twisted magnetic field lines under the simultaneous influence of photospheric line-tying and constraining by neighboring flux loops. The loops would be violently unstable without these two ingredients (i.e. for the corresponding tokamak problem). It is shown that line-tying alone in not sufficient for stability, but the neighboring flux tubes provide a normal boundary condition similar to a conducting shell in tokamaks. This stabilization gets lost on the time scale associated with reconnection of the tangetial magnetic field discontinuities present in the many-loop system. On this time scale the magnetic energy, which has been built up during the twisting of the field lines, gets released, resulting in a disruption of the loop. This process may be considered as the single loop variant of Parker's solar flare model.

  10. 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.

  11. 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.

  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. Loop heat pipe radiator

    SciTech Connect

    Sarraf, D.B.; Gernert, N.J.

    1996-03-01

    This paper describes the design and testing of a Loop Heat Pipe Radiator (LHPR) which was developed as an alternative to state-of-the-art axially-grooved heat pipes for space-based heat rejection which would be usable with tubing made of aluminum foil covered with a carbon-epoxy composite. The LHPR had an aluminum envelope and a polymer wick, and used ammonia as a working fluid. It was 4 meters long with a mass of 1.4 kg. The LHPR transported 500 watts at a 2.3 meter adverse inclination and 1500 watts when horizontal. This non-optimized LHPR had a 3000 watt-meter capability, which is four times greater than an axially-grooved heat pipe of similar power-handling capability and mass. In addition to a higher power handling capability, the LHPR has a much higher capillary margin than axially-grooved pipes. That high capillary margin simplifies ground testing in a 1-g environment by reducing the need for the careful levelling and vibration reduction required by axially-grooved pipes. {copyright} {ital 1996 American Institute of Physics.}

  14. Modeling Loop Entropy

    PubMed Central

    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. PMID:21187223

  15. 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.

  16. 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.

  17. Laparoscopy in Afferent Loop Obstruction Presenting as Acute Pancreatitis

    PubMed Central

    Pettinato, Giovanna; Romessis, Matheos; Ferrari Bravo, Andrea; Barozzi, Geraldine; Giovanetti, Maurizio

    2006-01-01

    Background: We describe an afferent loop obstruction caused by an adhesion band in a case of distal gastrectomy with Roux-en-Y end-to-side jejunal anastomosis for cancer. Methods: An initial clinical presentation of acute pancreatitis was ruled out by a computed tomography scan, which revealed intestinal obstruction; it was then confirmed on laparoscopy. Definitive treatment was laparoscopic adhesiolysis. A complete review of the literature concerning afferent loop obstructions is presented. Results: The treatment was successful, with minimal postoperative pain, and the 5-day hospital stay was uncomplicated. The patient remains asymptomatic at 1-year follow-up. Conclusions: The authors advocate minimally invasive surgery as a complete diagnostic and therapeutic alternative to emergency laparotomy in cases where afferent loop syndrome is suspected, and acknowledge that prompt surgery has a higher rate of success and reduces operative morbidity and mortality. PMID:16882437

  18. 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.

  19. 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.

  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. 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.

  2. 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.

  3. Capillary Pumped Loop 3 Flight Experiment Overview

    NASA Technical Reports Server (NTRS)

    Ottenstein, Laura

    1999-01-01

    The Capillary Pumped Loop 3 (CAPL 3) Experiment is a follow on to the CAPL 1 and CAPL 2 experiments which flew on STS-60 (2/94) and STS-69 (9/95), respectively. CAPL 3 is tentatively scheduled to fly on the Space Shuttle in late 2000 as part of the Hitchhiker Experiments Advancing Technology (HEAT) payload. The experiment is a joint Naval Research Laboratory (NRL)/Goddard Space Flight Center (GSFC) payload which will meet technology objectives for both the Department of Defense and NASA. The primary objective of CAPL 3 is to demonstrate in space a multiple evaporator capillary pumped loop system, capable of reliable start-up, reliable continuous operation, and at least 50% heat load sharing with hardware for a deployable radiator. CAPL 3 is a full scale CPL system with four parallel capillary evaporators. The loop also contains a capillary starter pump, 8 parallel direct condensation condensers with associated flow regulators, a back pressure regulator, a two-phase reservoir, and various headers and transport tubing. A variable conductance heat pipe is located between one of the evaporators and the experiment radiator to provide a cooling source for the demonstration of heat load sharing. The experiment has an operating power range of 100 W to approximately 1400 W. The experiment ammonia charge will cause it to transition to a fixed conductance mode of operation if the radiator usage reaches 85%. Ambient functional tests have been performed on the experiment. Tests performed included start-up, low power, power cycles, high power, heat load sharing, variable/fixed conductance transition, saturation temperature changes, and pressure primes while the system was operating. The majority of the testing was performed at an ammonia saturation temperature of 30C, but a few tests were done at temperatures above and below this. The testing was highly successful. Details of the tests performed and a discussion of the results will be given in the presentation.

  4. 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.

  5. 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.

  6. SDO Sees Brightening Magnetic Loops

    NASA Image and Video Library

    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. Automatic blocking of nested loops

    NASA Technical Reports Server (NTRS)

    Schreiber, Robert; Dongarra, Jack J.

    1990-01-01

    Blocked algorithms have much better properties of data locality and therefore can be much more efficient than ordinary algorithms when a memory hierarchy is involved. On the other hand, they are very difficult to write and to tune for particular machines. The reorganization is considered of nested loops through the use of known program transformations in order to create blocked algorithms automatically. The program transformations used are strip mining, loop interchange, and a variant of loop skewing in which invertible linear transformations (with integer coordinates) of the loop indices are allowed. Some problems are solved concerning the optimal application of these transformations. It is shown, in a very general setting, how to choose a nearly optimal set of transformed indices. It is then shown, in one particular but rather frequently occurring situation, how to choose an optimal set of block sizes.

  8. 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.

  9. SDO Sees Flourishing Magnetic Loops

    NASA Image and Video Library

    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...

  10. 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 ...

  11. 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 ...

  12. 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.

  13. 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

  14. 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.

  15. 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.

  16. 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

  17. 2F and 2H evaporator loop evaluation closure report

    SciTech Connect

    Bates, W.F.

    1994-01-28

    As a result of the Concentrate Transfer System (CTS) tank ventilation system contamination event, a task team was formed to evaluate instrument loops associated with waste reduction equipment. During the event a conductivity probe designed to provide an alarm and initiate an interlock failed to respond to the presence of liquid. An investigation revealed that the probe had become disconnected from the loop. The daily functional check of the conductivity probe circuit only tested the circuit continuity from the ventilation unit to the control room and did not actually test the probe. To test the continuity, a test switch was used to simulate the conducting probe. Because the functional check did not test each part of the loop, the test could be satisfactorily completed even though the probe itself was inoperable. The function of the task team was to develop a list of loops and interlocks prioritized by importance and likelihood of similar failure. The team evaluated the associated loop calibration and functional test procedures to verify that they are adequate to ensure loop performance on a periodic frequency. This report documents the evaluation findings and associated actions required prior to startup of the 2F and 2H evaporators.

  18. 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.

  19. 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.

  20. The Structure of Coronal Loops

    NASA Technical Reports Server (NTRS)

    Antiochos, Spiro K.

    2009-01-01

    It is widely believed that the simple coronal loops observed by XUV imagers, such as EIT, TRACE, or XRT, actually have a complex internal structure consisting of many (perhaps hundreds) of unresolved, interwoven "strands". According to the nanoflare model, photospheric motions tangle the strands, causing them to reconnect and release the energy required to produce the observed loop plasma. Although the strands, themselves, are unresolved by present-generation imagers, there is compelling evidence for their existence and for the nanoflare model from analysis of loop intensities and temporal evolution. A problem with this scenario is that, although reconnection can eliminate some of the strand tangles, it cannot destroy helicity, which should eventually build up to observable scales. we consider, therefore, the injection and evolution of helicity by the nanoflare process and its implications for the observed structure of loops and the large-scale corona. we argue that helicity does survive and build up to observable levels, but on spatial and temporal scales larger than those of coronal loops. we discuss the implications of these results for coronal loops and the corona, in general .

  1. 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.

  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. 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

  4. Structural families in loops of homologous proteins: automatic classification, modelling and application to antibodies.

    PubMed

    Martin, A C; Thornton, J M

    1996-11-15

    Loop regions of polypeptide in homologous proteins may be classified into structural families. A method is described by which this classification may be performed automatically and "key residue" templates, which may be responsible for the loop adopting a given conformation, are defined. The technique has been applied to the hypervariable loops of antibodies and the results are compared with the previous definition of canonical classes. We have extended these definitions and provide complete sets of structurally determining residues (SDRs) for the observed clusters including the first set of key residues for seven-residue CDR-H3 loops.

  5. Invariant measure of the one-loop quantum gravitational backreaction on inflation

    NASA Astrophysics Data System (ADS)

    Miao, S. P.; Tsamis, N. C.; Woodard, R. P.

    2017-06-01

    We use dimensional regularization in pure quantum gravity on a de Sitter background to evaluate the one-loop expectation value of an invariant operator which gives the local expansion rate. We show that the renormalization of this nonlocal composite operator can be accomplished using the counterterms of a simple local theory of gravity plus matter, at least at one-loop order. This renormalization completely absorbs the one-loop correction, which accords with the prediction that the lowest secular backreaction should be a two-loop effect.

  6. 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.

  7. 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.

  8. 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.

  9. 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

  10. 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.

  11. 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)

  12. 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.

  13. 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.

  14. Constraints on Nonuniform Expansion in Coronal Loops

    NASA Astrophysics Data System (ADS)

    Kucera, Therese A.; DeForest, Craig; Klimchuk, James A.; Young, Peter R.

    2017-08-01

    We use measurements of coronal loop properties to constrain the hypothesis that coronal loops expand differently in different directions. A long standing problem in understanding coronal loops is that although the magnetic field is expected to expand with altitude and does indeed seem to do so on scales of active regions, individual loops seem to have fairly uniform diameters along the length of the loop. Malanushenko & Schrijver (2013) have suggested that loops may be expanding, but with a non-circular cross section. In this scenario a loop might have a constant width in the plane of the sky, but expand along the line of sight. Furthermore, such loops might be easier to see from the point of view that does not show expansion. We use Hinode/EIS and SDO/AIA data to measure loop intensities, electron densities, temperatures and dimensions in order to determine the extent to which loops may be expanding along the line of sight.

  15. 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.

  16. 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.

  17. 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.

  18. Direct Demonstration That Loop1 of Scap Binds to Loop7

    PubMed Central

    Zhang, Yinxin; Lee, Kwang Min; Kinch, Lisa N.; Clark, Lindsay; Grishin, Nick V.; Rosenbaum, Daniel M.; Brown, Michael S.; Goldstein, Joseph L.; Radhakrishnan, Arun

    2016-01-01

    Cholesterol homeostasis is mediated by Scap, a polytopic endoplasmic reticulum (ER) protein that transports sterol regulatory element-binding proteins from the ER to Golgi, where they are processed to forms that activate cholesterol synthesis. Scap has eight transmembrane helices and two large luminal loops, designated Loop1 and Loop7. We earlier provided indirect evidence that Loop1 binds to Loop7, allowing Scap to bind COPII proteins for transport in coated vesicles. When ER cholesterol rises, it binds to Loop1. We hypothesized that this causes dissociation from Loop7, abrogating COPII binding. Here we demonstrate direct binding of the two loops when expressed as isolated fragments or as a fusion protein. Expressed alone, Loop1 remained intracellular and membrane-bound. When Loop7 was co-expressed, it bound to Loop1, and the soluble complex was secreted. A Loop1-Loop7 fusion protein was also secreted, and the two loops remained bound when the linker between them was cleaved by a protease. Point mutations that disrupt the Loop1-Loop7 interaction prevented secretion of the Loop1-Loop7 fusion protein. These data provide direct documentation of intramolecular Loop1-Loop7 binding, a central event in cholesterol homeostasis. PMID:27068746

  19. 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

  20. 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.

  1. 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.

  2. 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.

  3. QED representation for the net of causal loops

    NASA Astrophysics Data System (ADS)

    Ciolli, Fabio; Ruzzi, Giuseppe; Vasselli, Ezio

    2015-06-01

    The present work tackles the existence of local gauge symmetries in the setting of Algebraic Quantum Field Theory (AQFT). The net of causal loops, previously introduced by the authors, is a model independent construction of a covariant net of local C*-algebras on any 4-dimensional globally hyperbolic space-time, aimed to capture structural properties of any reasonable quantum gauge theory. Representations of this net can be described by causal and covariant connection systems, and local gauge transformations arise as maps between equivalent connection systems. The present paper completes these abstract results, realizing QED as a representation of the net of causal loops in Minkowski space-time. More precisely, we map the quantum electromagnetic field Fμν, not free in general, into a representation of the net of causal loops and show that the corresponding connection system and the local gauge transformations find a counterpart in terms of Fμν.

  4. 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…

  5. 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…

  6. 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.

  7. LISA Pathfinder: OPD loop characterisation

    NASA Astrophysics Data System (ADS)

    Born, Michael; LPF Collaboration

    2017-05-01

    The optical metrology system (OMS) of the LISA Pathfinder mission is measuring the distance between two free-floating test masses with unprecedented precision. One of the four OMS heterodyne interferometers reads out the phase difference between the reference and the measurement laser beam. This phase from the reference interferometer is common to all other longitudinal interferometer read outs and therefore subtracted. In addition, the phase is fed back via the digital optical pathlength difference (OPD) control loop to keep it close to zero. Here, we analyse the loop parameters and compare them to on-ground measurement results.

  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. Contraception with intrauterine plastic loops.

    PubMed

    Lippes, J

    1965-12-01

    Intrauterine plastic loops were inserted 2179 times into 1713 patients of the Planned Parenthood Center of Buffalo, New York and from the author's private practice between November 1, 1961 and June 30, 1964 to evaluate the acceptability, effectiveness, reversibility, and side effects of this contraceptive method. Median age of the patients was 26 and their median parity 3. At the Planned Parenthood Center, patients are offered a choice of oral contraception (OC), condoms, diaphragms, jellies, rhythm, and the loop. During 1962, 30% of the new patients chose the loop. In 1963, 48% of new patients chose intrauterine contraception, and this proportion continued through June 1964. It rose to 55% early in 1965. 41 pregnancies occurred giving an overall pregnancy rate of 2.2/100 woman years for all loops. Loop D had a rate of 1.0/100 woman years. The pregnancy rate was calculated according to Potter's life table procedure. These rates compared favorably with a diaphragm failure rate of 4/100 woman years reported in the Indianapolis study or the diaphragm failure rate of 14.4 reported by Westoff and Potter, as well as with the rate of 2.1 for OC reported by Cook, Gamble, and Satterthwaite. 23 patients became pregnant with a loop in situ. There were 20 loop failures where location of the device was undetermined. Before November 30, 1964, 32 patients had discontinued intrauterine contraception because they wanted a child. All but 3 became pregnant. There were no abortions. The devices are not tolerated by all patients. Side effects consisted primarily of expulsions and bleeding, but pain and the possibility of infection were sometimes present. The monthly expulsion rate decreased with continued use. Most expulsions occurred in the 1st 6 months of use, and the largest and heaviest device had the lowest expulsion rate. 90% of the patients exhibited some alteration of their menstrual pattern. Cramps or pain were only a minor reason for terminating intrauterine contraception

  10. 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

  11. Cascading Post-coronal Loops

    NASA Image and Video Library

    2017-04-24

    An active region that had just rotated into view blasted out a coronal mass ejection, which was immediately followed by a bright series of post-coronal loops seeking to reorganize that region's magnetic field (April 19, 2017). We have observed this phenomenon numerous times, but this one was one of the longest and clearest sequences we have seen in years. The bright loops are actually charged particles spinning along the magnetic field lines. The action was captured in a combination of two wavelengths of extreme ultraviolet light over a period of about 20 hours. Movies are available at https://photojournal.jpl.nasa.gov/catalog/PIA21598

  12. 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.

  13. 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

  14. 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.

  15. 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.

  16. 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

  17. Closed-Loop Prevention of Hypotension in the Heartbeating Brain-Dead Porcine Model.

    PubMed

    Soltesz, Kristian; Sturk, Christopher; Paskevicius, Audrius; Liao, Qiuming; Qin, Guangqi; Sjoberg, Trygve; Steen, Stig

    2017-06-01

     Objective: The purpose of this paper is to demonstrate feasibility of a novel closed-loop controlled therapy for prevention of hypertension in the heartbeating brain-dead porcine model. Dynamic modeling and system identification were based on in vivo data. A robust controller design was obtained for the identified models. Disturbance attenuation properties and reliability of operation of the resulting control system were evaluated in vivo. The control system responded both predictably and consistently to external disturbances. It was possible to prevent mean arterial pressure to fall below a user-specified reference throughout 24 h of completely autonomous operation. Parameter variability in the identified models confirmed the benefit of closed-loop controlled administration of the proposed therapy. The evaluated robust controller was able to mitigate both process uncertainty and external disturbances. Prevention of hypertension is critical to the care of heartbeating brain-dead organ donors. Its automation would likely increase the fraction of organs suitable for transplantation from this patient group.

  18. 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.

  19. 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.

  20. Open loop model for WDM links

    NASA Astrophysics Data System (ADS)

    D, Meena; Francis, Fredy; T, Sarath K.; E, Dipin; Srinivas, T.; K, Jayasree V.

    2014-10-01

    Wavelength Division Multiplexing (WDM) techniques overfibrelinks helps to exploit the high bandwidth capacity of single mode fibres. A typical WDM link consisting of laser source, multiplexer/demultiplexer, amplifier and detectoris considered for obtaining the open loop gain model of the link. The methodology used here is to obtain individual component models using mathematical and different curve fitting techniques. These individual models are then combined to obtain the WDM link model. The objective is to deduce a single variable model for the WDM link in terms of input current to system. Thus it provides a black box solution for a link. The Root Mean Square Error (RMSE) associated with each of the approximated models is given for comparison. This will help the designer to select the suitable WDM link model during a complex link design.

  1. 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

  2. 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

  3. 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

  4. Loop quantum cosmology and singularities.

    PubMed

    Struyve, Ward

    2017-08-15

    Loop quantum gravity is believed to eliminate singularities such as the big bang and big crunch singularity. This belief is based on studies of so-called loop quantum cosmology which concerns symmetry-reduced models of quantum gravity. In this paper, the problem of singularities is analysed in the context of the Bohmian formulation of loop quantum cosmology. In this formulation there is an actual metric in addition to the wave function, which evolves stochastically (rather than deterministically as the case of the particle evolution in non-relativistic Bohmian mechanics). Thus a singularity occurs whenever this actual metric is singular. It is shown that in the loop quantum cosmology for a homogeneous and isotropic Friedmann-Lemaître-Robertson-Walker space-time with arbitrary constant spatial curvature and cosmological constant, coupled to a massless homogeneous scalar field, a big bang or big crunch singularity is never obtained. This should be contrasted with the fact that in the Bohmian formulation of the Wheeler-DeWitt theory singularities may exist.

  5. 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

  6. 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.

  7. 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.

  8. Ponderomotive Acceleration in Coronal Loops

    NASA Astrophysics Data System (ADS)

    Dahlburg, Russell B.; Laming, J. Martin; Taylor, Brian; Obenschain, Keith

    2017-08-01

    Ponderomotive acceleration has been asserted to be a cause of the First Ionization Potential (FIP) effect, the by now 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 ``byproduct'' 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 a coronal loops with an axial magnetic field from 0.005 Teslas to 0.02 Teslas and lengths from 25000 km to 75000 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.

  9. 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

  10. 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.

  11. 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.

  12. Detection and characterization of R-loops at the murine immunoglobulin Sα region.

    PubMed

    Kao, Yu-Pu; Hsieh, Wen-Chuan; Hung, Shu-Ting; Huang, Chiun-Wei; Lieber, Michael R; Huang, Feng-Ting

    2013-06-01

    IgA is the most abundant antibody in mammals. However, the mechanism of its class switching is still not clear. The formation of the R-loops, as the target for AID, has been proposed to play a crucial role during mammalian class switch recombination. Here, we provide a systematic evaluation of R-loops at Sα (IgA) in CH12F3-2A cells, which is a unique cell model system for class switch recombination because of its consistent switching to IgA upon stimulation. The results of R-loop analysis demonstrate distinct features specific to Sα. Some R-loops may initiate from the end of Iα, but all terminate exclusively within Sα. Time-course analysis also indicates that the percentage of R-loops peaks prior to the occurrence of class switch recombination. This is the first demonstration that R-loops form at Sαin vitro and in situ, despite variable G density and relatively few GGGG clusters in Sα. The short distance from the promoter to Sα may compensate for the less robust R-loop-forming factors at Sα relative to other switch regions. In conclusion, R-loops at the Sα region further support R-loop formation as a general feature of all stimulated switch regions. Copyright © 2012 Elsevier Ltd. All rights reserved.

  13. 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.

  14. Evolution in a Braided Loop Ensemble

    NASA Image and Video Library

    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...

  15. Crystal packing effects on protein loops.

    PubMed

    Rapp, Chaya S; Pollack, Rena M

    2005-07-01

    The effects of crystal packing on protein loop structures are examined by (1) a comparison of loops in proteins that have been crystallized in alternate packing arrangements, and (2) theoretical prediction of loops both with and without the inclusion of the crystal environment. Results show that in a minority of cases, loop geometries are dependent on crystal packing effects. Explicit representation of the crystal environment in a loop prediction algorithm can be used to model these effects and to reconstruct the structures, and relative energies, of a loop in alternative packing environments. By comparing prediction results with and without the inclusion of the crystal environment, the loop prediction algorithm can further be used to identify cases in which a crystal structure does not represent the most stable state of a loop in solution. We anticipate that this capability has implications for structural biology.

  16. Latino College Completion: Michigan

    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: 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…

  18. Latino College Completion: Virginia

    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: Louisiana

    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: Missouri

    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: Georgia

    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: Utah

    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: Vermont

    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: Arizona

    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: Alaska

    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: Colorado

    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: Wisconsin

    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: Pennsylvania

    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: Delaware

    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. Latino College Completion: Alabama

    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…

  11. Latino College Completion: Illinois

    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…

  12. 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…

  13. Latino College Completion: Arkansas

    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…

  14. 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…

  15. Latino College Completion: Minnesota

    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: Nebraska

    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: Indiana

    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: Kansas

    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: Wyoming

    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: Washington

    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: Tennessee

    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: Idaho

    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: Kentucky

    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: Oklahoma

    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: 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…

  7. Latino College Completion: Texas

    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: Oregon

    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: 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…

  10. 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…

  11. 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…

  12. 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…

  13. 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…

  14. 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…

  15. 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…

  16. Summary of ALSEP Test Loop Solvent Irradiation Testing

    SciTech Connect

    Peterman, Dean Richard; Olson, Lonnie Gene

    2016-08-01

    Separating the minor actinide elements (americium and curium) from the fission product lanthanides is an important step in closing the nuclear fuel cycle. Isolating the minor actinides will allow transmuting them to short lived or stable isotopes in fast reactors, thereby reducing the long-term hazard associated with these elements. The Actinide Lanthanide Separation Process (ALSEP) is being developed by the DOE-NE Material Recovery and Waste Form Development Campaign to accomplish this separation with a single process. To develop a fundamental understanding of the solvent degradation mechanisms for the ALSEP Process, testing was performed in the INL Radiolysis/Hydrolysis Test Loop for the extraction section of the ALSEP flowsheet. This work culminated in the completion of the level two milestone (M2FT-16IN030102021) "Complete ALSEP test loop solvent irradiation test.” This report summarizes the testing performed and the impact of radiation on the ALSEP Process performance as a function of dose.

  17. 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.

  18. 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.

  19. 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.

  20. 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…

  1. Bootstrapping a five-loop amplitude using Steinmann relations

    DOE PAGES

    Caron-Huot, Simon; Dixon, Lance J.; McLeod, Andrew; ...

    2016-12-05

    Here, 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.

  2. 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.

  3. 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.

  4. 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

  5. The Statistical Loop Analyzer (SLA)

    NASA Technical Reports Server (NTRS)

    Lindsey, W. C.

    1985-01-01

    The statistical loop analyzer (SLA) is designed to automatically measure the acquisition, tracking and frequency stability performance characteristics of symbol synchronizers, code synchronizers, carrier tracking loops, and coherent transponders. Automated phase lock and system level tests can also be made using the SLA. Standard baseband, carrier and spread spectrum modulation techniques can be accomodated. Through the SLA's phase error jitter and cycle slip measurements the acquisition and tracking thresholds of the unit under test are determined; any false phase and frequency lock events are statistically analyzed and reported in the SLA output in probabilistic terms. Automated signal drop out tests can be performed in order to trouble shoot algorithms and evaluate the reacquisition statistics of the unit under test. Cycle slip rates and cycle slip probabilities can be measured using the SLA. These measurements, combined with bit error probability measurements, are all that are needed to fully characterize the acquisition and tracking performance of a digital communication system.

  6. 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.

  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. Double loop control strategy with different time steps based on human characteristics.

    PubMed

    Gu, Gwang Min; Lee, Jinoh; Kim, Jung

    2012-01-01

    This paper proposes a cooperative control strategy in consideration of the force sensitivity of human. The strategy consists of two loops: one is the intention estimation loop whose sampling time can be variable in order to investigate the effect of the sampling time; the other is the position control loop with fixed time step. A high sampling rate is not necessary for the intention estimation loop due to the bandwidth of the mechanoreceptors in humans. In addition, the force sensor implemented in the robot is sensitive to the noise induced from the sensor itself and tremor of the human. Multiple experiments were performed with the experimental protocol using various time steps of the intention estimation loop to find the suitable sampling times in physical human robot interaction. The task involves pull-and-push movement with a two-degree-of-freedom robot, and the norm of the interaction force was obtained for each experiment as the measure of the cooperative control performance.

  9. Loop versus end colostomy reversal: has anything changed?

    PubMed

    Bruns, B R; DuBose, J; Pasley, J; Kheirbek, T; Chouliaras, K; Riggle, A; Frank, M K; Phelan, H A; Holena, D; Inaba, K; Diaz, J; Scalea, T M

    2015-10-01

    Though primary repair of colon injuries is preferred, certain injury patterns require colostomy creation. Colostomy reversal is associated with significant morbidity and healthcare cost. Complication rates may be influenced by technique of diversion (loop vs. end colostomy), though this remains ill-defined. We hypothesized that reversal of loop colostomies is associated with fewer complications than end colostomies. This is a retrospective, multi-institutional study (four, level-1 trauma centers) of patients undergoing colostomy takedown for trauma during the time period 1/2006-12/2012. Data were collected from index trauma admission and subsequent admission for reversal and included demographics and complications of reversal. Student's t test was used to compare continuous variables against loop versus end colostomy. Discrete variables were compared against both groups using Chi-squared tests. Over the 6-year study period, 218 patients underwent colostomy takedown after trauma with a mean age of 30; 190 (87%) were male, 162 (74%) had penetrating injury as their indication for colostomy, and 98 (45%) experienced at least one complication. Patients in the end colostomy group (n = 160) were more likely to require midline laparotomy (145 vs. 18, p < 0.001), had greater intra-operative blood loss (260.7 vs. 99.4 mL, p < 0.001), had greater hospital length of stay (8.4 vs. 5.5 days, p < 0.001), and had more overall complications (81 vs. 17, p = 0.005) than patients managed with loop colostomy (n = 58). Local takedown of a loop colostomy is safe and leads to shorter hospital stays, less intra-operative blood loss, and fewer complications when compared to end colostomy.

  10. 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.

  11. Quantum reduced loop gravity and the foundation of loop quantum cosmology

    NASA Astrophysics Data System (ADS)

    Alesci, Emanuele; Cianfrani, Francesco

    2016-06-01

    Quantum reduced loop gravity is a promising framework for linking loop quantum gravity and the effective semiclassical dynamics of loop quantum cosmology. We review its basic achievements and its main perspectives, outlining how it provides a quantum description of the Universe in terms of a cuboidal graph which constitutes the proper framework for applying loop techniques in a cosmological setting.

  12. 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.

  13. Two-loop quantum gravity

    NASA Astrophysics Data System (ADS)

    van de Ven, Anton E. M.

    1992-07-01

    We prove the existence of a nonrenormalizable infinity in the two-loop effective action of perturbative quantum gravity by means of an explicit calculation. Our final result agrees with that obtained by earlier authors. We use the background-field method in coordinate space, combined with dimensional regularization and a heat kernel representation for the propagators. General covariance is manifestly preserved. Only vacuum graphs in the presence of an on-shell background metric need to be calculated. We extend the background covariant harmonic gauge to include terms nonlinear in the quantum gravitational fields and allow for general reparametrizations of those fields. For a particular gauge choice and field parametrization only two three-graviton and six four-graviton vertices are present in the action. Calculational labor is further reduced by restricting to backgrounds, which are not only Ricci-flat, but satisfy an additional constraint bilinear in the Weyl tensor. To handle the still formidable amount of algebra, we use the symbolic manipulation program FORM. We checked that the on-shell two-loop effective action is in fact independent of all gauge and field redefinition parameters. A two-loop analysis for Yang-Mills fields is included as well, since in that case we can give full details as well as simplify earlier analyses.

  14. 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.

  15. 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.

  16. 68. COMPLETED ASSEMBLY SHOWING BARGES, BRIDGE AND SUPPORT CARRIAGE AT ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    68. COMPLETED ASSEMBLY SHOWING BARGES, BRIDGE AND SUPPORT CARRIAGE AT THE BASE OF THE LAUNCHING SLAB LOOKING EAST, April 26, 1948. - Variable Angle Launcher Complex, Variable Angle Launcher, CA State Highway 39 at Morris Reservior, Azusa, Los Angeles County, CA

  17. 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.

  18. Complete-denture esthetics.

    PubMed

    Engelmeier, R L

    1996-01-01

    This review of complete denture esthetics addresses the process of tooth selection, tooth arrangement, and characterization of the denture bases. The guidelines discussed in this article are all gleaned from the classic prosthodontic literature. These principles, which were developed over the past century, coupled with state-of-the-art materials are artificial teeth enable contemporary dentists to fabricate complete dentures with a level of esthetics never before possible.

  19. 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.

  20. 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

  1. The Thai Phase III HIV Type 1 Vaccine Trial (RV144) Regimen Induces Antibodies That Target Conserved Regions Within the V2 Loop of gp120

    PubMed Central

    Billings, Erik; Rao, Mangala; Williams, Constance; Zolla-Pazner, Susan; Bailer, Robert T.; Koup, Richard A.; Madnote, Sirinan; Arworn, Duangnapa; Shen, Xiaoying; Tomaras, Georgia D.; Currier, Jeffrey R.; Jiang, Mike; Magaret, Craig; Andrews, Charla; Gottardo, Raphael; Gilbert, Peter; Cardozo, Timothy J.; Rerks-Ngarm, Supachai; Nitayaphan, Sorachai; Pitisuttithum, Punnee; Kaewkungwal, Jaranit; Paris, Robert; Greene, Kelli; Gao, Hongmei; Gurunathan, Sanjay; Tartaglia, Jim; Sinangil, Faruk; Korber, Bette T.; Montefiori, David C.; Mascola, John R.; Robb, Merlin L.; Haynes, Barton F.; Ngauy, Viseth; Michael, Nelson L.; Kim, Jerome H.; de Souza, Mark S.

    2012-01-01

    Abstract The Thai Phase III clinical trial (RV144) showed modest efficacy in preventing HIV-1 acquisition. Plasma collected from HIV-1-uninfected trial participants completing all injections with ALVAC-HIV (vCP1521) prime and AIDSVAX B/E boost were tested for antibody responses against HIV-1 gp120 envelope (Env). Peptide microarray analysis from six HIV-1 subtypes and group M consensus showed that vaccination induced antibody responses to the second variable (V2) loop of gp120 of multiple subtypes. We further evaluated V2 responses by ELISA and surface plasmon resonance using cyclic (Cyc) and linear V2 loop peptides. Thirty-one of 32 vaccine recipients tested (97%) had antibody responses against Cyc V2 at 2 weeks postimmunization with a reciprocal geometric mean titer (GMT) of 1100 (range: 200–3200). The frequency of detecting plasma V2 antibodies declined to 19% at 28 weeks post-last injection (GMT: 110, range: 100–200). Antibody responses targeted the mid-region of the V2 loop that contains conserved epitopes and has the amino acid sequence KQKVHALFYKLDIVPI (HXB2 Numbering sequence 169–184). Valine at position 172 was critical for antibody binding. The frequency of V3 responses at 2 weeks postimmunization was modest (18/32, 56%) with a GMT of 185 (range: 100–800). In contrast, naturally infected HIV-1 individuals had a lower frequency of antibody responses to V2 (10/20, 50%; p=0.003) and a higher frequency of responses to V3 (19/20, 95%), with GMTs of 400 (range: 100–3200) and 3570 (range: 200–12,800), respectively. RV144 vaccination induced antibodies that targeted a region of the V2 loop that contains conserved epitopes. Early HIV-1 transmission events involve V2 loop interactions, raising the possibility that anti-V2 antibodies in RV144 may have contributed to viral inhibition. PMID:23035746

  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. Magnetic Helicity Injection and Sigmoidal Coronal Loops

    NASA Astrophysics Data System (ADS)

    Yamamoto, Tetsuya T.; Kusano, K.; Maeshiro, T.; Yokoyama, T.; Sakurai, T.

    2005-05-01

    We studied the relationship between magnetic helicity injection and the formation of sigmoidal loops. We analyzed seven active regions: three regions showed coronal loops similar to the potential field, and four regions showed the sigmoidal loops. The magnetic helicity injection rate was evaluated using the method proposed by Kusano et al. In order to compare the helicity of regions of various sizes, we defined the normalized helicity injection rate as the magnetic helicity injection rate divided by the magnetic flux squared. We found that the sigmoidal regions and nonsigmoidal regions have comparable normalized helicity injection rates. Next, we calculated the magnetic helicity content of the sigmoidal loops by using the magnetic flux tube model (Longcope & Welsch) and compared it with the magnetic helicity injected from around the footpoints of three sigmoidal loops. For two sigmoidal loops, it is found that these values are comparable. Another loop showed significant disagreement between helicity injection rate and its magnetic helicity content. Excluding this region on the basis of its complexity (perhaps multiple loops forming a sigmoidal loop), we can conclude that geometric twist of the sigmoidal loops is consistent with the magnetic helicity injected from around the footpoints of the sigmoidal loops.

  5. Orientability of loop processes in relative locality

    NASA Astrophysics Data System (ADS)

    Chen, Lin-Qing

    2013-12-01

    Inspired by recent results of unusual properties of loop processes in relative locality, we introduce a way to classify loops in the case of κ-Poincaré momentum space. We show that the notion of orientability is deeply connected to a few essential properties of loop processes. Nonorientable loops have effective curvature, which explicitly breaks translation symmetry, and can lead to a breaking of causality and global momentum conservation. Orientable loops, on the other hand, are “flat.” Causality and global momentum conservation are all well preserved in these kinds of loops. We comment that the nontrivial classical loops in relative locality might be understood as dual effects from general relativity, and some physical implications are discussed.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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 .

  11. 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

  12. 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.

  13. Exploring the Dynamics of Propeller Loops in Human Telomeric DNA Quadruplexes Using Atomistic Simulations

    PubMed Central

    2017-01-01

    We have carried out a series of extended unbiased molecular dynamics (MD) simulations (up to 10 μs long, ∼162 μs in total) complemented by replica-exchange with the collective variable tempering (RECT) approach for several human telomeric DNA G-quadruplex (GQ) topologies with TTA propeller loops. We used different AMBER DNA force-field variants and also processed simulations by Markov State Model (MSM) analysis. The slow conformational transitions in the propeller loops took place on a scale of a few μs, emphasizing the need for long simulations in studies of GQ dynamics. The propeller loops sampled similar ensembles for all GQ topologies and for all force-field dihedral-potential variants. The outcomes of standard and RECT simulations were consistent and captured similar spectrum of loop conformations. However, the most common crystallographic loop conformation was very unstable with all force-field versions. Although the loss of canonical γ-trans state of the first propeller loop nucleotide could be related to the indispensable bsc0 α/γ dihedral potential, even supporting this particular dihedral by a bias was insufficient to populate the experimentally dominant loop conformation. In conclusion, while our simulations were capable of providing a reasonable albeit not converged sampling of the TTA propeller loop conformational space, the force-field description still remained far from satisfactory. PMID:28475322

  14. Hardware-in-the-loop grid simulator system and method

    DOEpatents

    Fox, John Curtiss; Collins, Edward Randolph; Rigas, Nikolaos

    2017-05-16

    A hardware-in-the-loop (HIL) electrical grid simulation system and method that combines a reactive divider with a variable frequency converter to better mimic and control expected and unexpected parameters in an electrical grid. The invention provides grid simulation in a manner to allow improved testing of variable power generators, such as wind turbines, and their operation once interconnected with an electrical grid in multiple countries. The system further comprises an improved variable fault reactance (reactive divider) capable of providing a variable fault reactance power output to control a voltage profile, therein creating an arbitrary recovery voltage. The system further comprises an improved isolation transformer designed to isolate zero-sequence current from either a primary or secondary winding in a transformer or pass the zero-sequence current from a primary to a secondary winding.

  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. [Operative hysteroscopy for myoma removal: Morcellation versus bipolar loop resection].

    PubMed

    Hamidouche, A; Vincienne, M; Thubert, T; Trichot, C; Demoulin, G; Nazac, A; Fernandez, H; Rivain, A-L; Deffieux, X

    2015-09-01

    To evaluate the results associated with hysteroscopic morcellation for submucous myomas removal, and to compare with those observed associated with bipolar loop resection. A retrospective comparative study was conducted in two universitary centers from January 2012 to December 2013. A total of 83 patients, who presented with submucous myomas type 0,1 and 2, were included. The number of myomas type 0,1 was 36 (71 %) and 15 (29 %) myomas type 2 in morcellation group versus 44 (59 %) myomas type 0,1 and 31 (41 %) type 2 in electrosurgical resection group (P=0.17). Hysteroscopic morcellation or electrosurgical resection with bipolar loop for removal submucous myomas were performed. Thirty-four patients underwent hysteroscopic morcellation using MyoSure(®), and 49 had hysteroscopic resection using Versapoint-24F(®) bipolar loop. The mean operative duration was 30minutes in morcellation group, compared to 31minutes in bipolar resection group (P=0.98). Complete myoma removal was achieved in 22 (64 %) patients in morcellation group, and in 34 (69 %) in bipolar resection group (P=0.65). There were no difference in the occuring of adverse events between the two. The prevalence of postoperative intra-uterine adherence was 10 % in morcellation group and 13.8 % in bipolar resection group (P=0.69). In the current short comparative series, hysteroscopic morcellation and bipolar loop resection were associated with comparable results for removal of submucous myomas. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

  17. 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.

  18. 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.

  19. 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.

  20. Face-Mask Removal: Movement and Time Associated With Cutting of the Loop Straps.

    PubMed

    Swartz, Erik E.; Norkus, Susan A.; Armstrong, Charles W.; Kleiner, Douglas M.

    2003-06-01

    OBJECTIVE: To quantify the amount of helmet movement, time for task completion, tool satisfaction, and overall efficiency for various face-mask removal tools during football helmet face-mask removal. DESIGN AND SETTING: Each subject performed one trial with the anvil pruner (AP), Face Mask Extractor (FME), PVC pipe cutter (PVC), and Trainer's Angel (TA). Each subject cut through 4 loop straps and removed the face mask while kneeling behind the athlete's head. SUBJECTS: Twenty-nine certified athletic trainers (age = 29.5 +/- 6.2 years, athletic training experience = 6.3 +/- 5.0 years). MEASUREMENTS: Time to complete the task was recorded. Total range of motion and total movement of the helmet were assessed using a 6-camera, 3-dimensional motion-capture system. Satisfaction scores were measured for each subject for each tool. Efficiency scores were calculated using time and total helmet-movement data. RESULTS: When using the FME, subjects were significantly faster than with all other tools (P <.05), and when using the AP and TA, they were significantly faster than with the PVC. No differences were noted between tools in either movement variable. Significant differences were noted for satisfaction (P <.05) for all comparisons except TA versus AP. Efficiency scores were FME, 11.6; AP, 14.3; TA, 14.5; and PVC, 22.9, with lower scores identifying increased efficiency. CONCLUSIONS: In general, subjects using the FME were superior in all variables except the movement variables. Future researchers should assess the removal task using specific protocols to determine whether the tools truly differ in terms of the movement created.

  1. Face-Mask Removal: Movement and Time Associated With Cutting of the Loop Straps

    PubMed Central

    Norkus, Susan A.; Armstrong, Charles W.; Kleiner, Douglas M.

    2003-01-01

    Objective: To quantify the amount of helmet movement, time for task completion, tool satisfaction, and overall efficiency for various face-mask removal tools during football helmet face-mask removal. Design and Setting: Each subject performed one trial with the anvil pruner (AP), Face Mask Extractor (FME), PVC pipe cutter (PVC), and Trainer's Angel (TA). Each subject cut through 4 loop straps and removed the face mask while kneeling behind the athlete's head. Subjects: Twenty-nine certified athletic trainers (age = 29.5 ± 6.2 years, athletic training experience = 6.3 ± 5.0 years). Measurements: Time to complete the task was recorded. Total range of motion and total movement of the helmet were assessed using a 6-camera, 3-dimensional motion-capture system. Satisfaction scores were measured for each subject for each tool. Efficiency scores were calculated using time and total helmet-movement data. Results: When using the FME, subjects were significantly faster than with all other tools (P < .05), and when using the AP and TA, they were significantly faster than with the PVC. No differences were noted between tools in either movement variable. Significant differences were noted for satisfaction (P < .05) for all comparisons except TA versus AP. Efficiency scores were FME, 11.6; AP, 14.3; TA, 14.5; and PVC, 22.9, with lower scores identifying increased efficiency. Conclusions: In general, subjects using the FME were superior in all variables except the movement variables. Future researchers should assess the removal task using specific protocols to determine whether the tools truly differ in terms of the movement created. PMID:12937522

  2. 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.

  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. Loop Virasoro Lie conformal algebra

    SciTech Connect

    Wu, Henan Chen, Qiufan; Yue, Xiaoqing

    2014-01-15

    The Lie conformal algebra of loop Virasoro algebra, denoted by CW, is introduced in this paper. Explicitly, CW is a Lie conformal algebra with C[∂]-basis (L{sub i} | i∈Z) and λ-brackets [L{sub i} {sub λ} L{sub j}] = (−∂−2λ)L{sub i+j}. Then conformal derivations of CW are determined. Finally, rank one conformal modules and Z-graded free intermediate series modules over CW are classified.

  5. Using the Meeting Graph Framework to Minimise Kernel Loop Unrolling for Scheduled Loops

    NASA Astrophysics Data System (ADS)

    Bachir, Mounira; Gregg, David; Touati, Sid-Ahmed-Ali

    This paper improves our previous research effort [1] by providing an efficient method for kernel loop unrolling minimisation in the case of already scheduled loops, where circular lifetime intervals are known. When loops are software pipelined, the number of values simultaneously alive becomes exactly known giving better opportunities for kernel loop unrolling. Furthermore, fixing circular lifetime intervals allows us to reduce the algorithmic complexity of our method compared to [1] by computing a new research space for minimal kernel loop unrolling. The meeting graph (MG) is one of the [3] frameworks proposed in the literature which models loop unrolling and register allocation together in a common formal framework for software pipelined loops. Although MG significantly improves loop register allocation, the computed loop unrolling may lead to unpractical code growth.

  6. Thermal Analysis of CDS Coronal Loops

    NASA Astrophysics Data System (ADS)

    Kimble, J. A.; Schmelz, J. T.; Nasraoui, K.; Rightmire, L. A.; Andrews, J. M.; Cirtain, J. W.

    2008-05-01

    The coronal loop data used for this analysis was obtained using the Coronal Diagnostic Spectrometer (CDS) aboard the Solar and Heliospheric Observatory on 2003 January 17 at 14:24:43 UT. We use the Chianti atomic physics database and the hybrid coronal abundances to determine temperatures and densities for positions along several loops. We chose six pixels along each loop as well as background pixels. The intensities of the background pixels are subtracted from each loop pixel to isolate the emission from the loop pixel, and then spectral lines with significant contributions to the loop intensities are selected. The loops were then analyzed with a forward folding process to produce differential emission measure (DEM) curves. Emission measure loci plots and DEM automatic inversions are then used to verify those conclusions. We find different results for each of these loops. One appears to be isothermal at each loop position, and the temperature does not change with height. The second appears to be multithermal at each position and the third seems to be consistent with two DEM spikes, which might indicate that there are two isothermal loops so close together, that they are not resolved by CDS. Solar physics research at the University of Memphis is supported by a Hinode subcontract from NASA/SAO as well as NSF ATM-0402729.

  7. 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.

  8. 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…

  9. 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.)…

  10. 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…

  11. 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…

  12. 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…

  13. 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.)…

  14. 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…

  15. 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

  16. 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

  17. 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.

  18. 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.

  19. 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

  20. 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.

  1. 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.

  2. Wilson Loops in Open String Theory

    NASA Astrophysics Data System (ADS)

    Shiraishi, Kiyoshi

    Wilson loop elements on torus are introduced into the partition function of open strings as Polyakov’s path integral at one-loop level. Mass spectra from compactification and expected symmetry breaking are illustrated by choosing the correct weight for the contributions from annulus and Möbius strip. We show that Jacobi’s imaginary transformation connects the mass spectra with the Wilson loops. The application to thermopartition function and cosmological implications are briefly discussed.

  3. Spectra of sparse regular graphs with loops.

    PubMed

    Metz, F L; Neri, I; Bollé, D

    2011-11-01

    We derive exact equations that determine the spectra of undirected and directed sparsely connected regular graphs containing loops of arbitrary lengths. The implications of our results for the structural and dynamical properties of network models are discussed by showing how loops influence the size of the spectral gap and the propensity for synchronization. Analytical formulas for the spectrum are obtained for specific lengths of the loops.

  4. 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

  5. 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.

  6. 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.

  7. 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.

  8. Teaching complete dentures.

    PubMed

    Lechner, S K

    1993-01-01

    Success in wearing complete denture depends, in order of importance, on motivation, neuromuscular control and technical considerations. To address the two aspects of motivation and neuromuscular control, fourth year students at Sydney University are taught a protocol which encompasses duplication of the patient's existing denture and modification of this duplicate to satisfy the patient's needs and wants. This modified duplicate denture acts as a diagnostic prototype which is used as a guide during construction of the new denture.

  9. Binary phase locked loops for Omega receivers

    NASA Technical Reports Server (NTRS)

    Chamberlin, K.

    1974-01-01

    An all-digital phase lock loop (PLL) is considered because of a number of problems inherent in an employment of analog PLL. The digital PLL design presented solves these problems. A single loop measures all eight Omega time slots. Memory-aiding leads to the name of this design, the memory-aided phase lock loop (MAPLL). Basic operating principles are discussed and the superiority of MAPLL over the conventional digital phase lock loop with regard to the operational efficiency for Omega applications is demonstrated.

  10. M-Brane Models and Loop Spaces

    NASA Astrophysics Data System (ADS)

    Sämann, Christian

    2012-06-01

    I review an extension of the ADHMN construction of monopoles to M-brane models. This extended construction gives a map from solutions to the Basu-Harvey equation to solutions to the self-dual string equation transgressed to loop space. Loop spaces appear in fact quite naturally in M-brane models. This is demonstrated by translating a recently proposed M5-brane model to loop space. Finally, I comment on some recent developments related to the loop space approach to M-brane models.

  11. Coronal Diagnostics Spectrometer Observations of Coronal Loops

    NASA Astrophysics Data System (ADS)

    Nasraoui, Kaouther; Schmelz, J. T.; Cirtain, J. W.; Del Zanna, G.; DeLuca, E. E.; Mason, H. E.

    2007-05-01

    Two side by side loops from the solar disk were analyzed. These two loops were observed with the Coronal Diagnostics Spectrometer on SOHO on 2003 January 17. The first loop was best seen in Mg IX at a wavelength of 368 angstroms and a peak formation temperature of Log T = 6.0. Seven pixels on the loop and one background pixel were chosen. The intensity of the background pixel was subtracted from each of the loop pixels. Only the lines that had a significant intensity after background subtraction were considered. A differential emission measure (DEM) curve was constructed for the background subtracted data using the forward folding technique. The DEM for most of these pixels had a spike shape at Log T equal to 5.85. This result shows that the loop is isothermal at most of these pixels. The second loop was best seen in Si XII at a wavelength of 520 angstroms and a peak formation temperature of Log T = 6.3. The same procedure was followed for the data analysis. After background subtraction only some hot lines had a significant intensity and a DEM curve was constructed for each loop pixel. This time the DEM is broader with a shape that shows that the loop plasma is multithermal with a log temperature range of 6.1 to 6.5. Solar physics research at the University of Memphis is supported by NSF ATM-0402729 and NASA NNG05GE68G.

  12. 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.

  13. 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.

  14. 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.

  15. 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

  16. The diversity of H3 loops determines the antigen‐binding tendencies of antibody CDR loops

    PubMed Central

    2016-01-01

    Abstract Of the complementarity‐determining regions (CDRs) of antibodies, H3 loops, with varying amino acid sequences and loop lengths, adopt particularly diverse loop conformations. The diversity of H3 conformations produces an array of antigen recognition patterns involving all the CDRs, in which the residue positions actually in contact with the antigen vary considerably. Therefore, for a deeper understanding of antigen recognition, it is necessary to relate the sequence and structural properties of each residue position in each CDR loop to its ability to bind antigens. In this study, we proposed a new method for characterizing the structural features of the CDR loops and obtained the antigen‐binding ability of each residue position in each CDR loop. This analysis led to a simple set of rules for identifying probable antigen‐binding residues. We also found that the diversity of H3 loop lengths and conformations affects the antigen‐binding tendencies of all the CDR loops. PMID:26749247

  17. 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.

  18. 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.

  19. 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

  20. 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.