NASA Astrophysics Data System (ADS)
Milić, Ivan; Atanacković, Olga
2014-10-01
State-of-the-art methods in multidimensional NLTE radiative transfer are based on the use of local approximate lambda operator within either Jacobi or Gauss-Seidel iterative schemes. Here we propose another approach to the solution of 2D NLTE RT problems, Forth-and-Back Implicit Lambda Iteration (FBILI), developed earlier for 1D geometry. In order to present the method and examine its convergence properties we use the well-known instance of the two-level atom line formation with complete frequency redistribution. In the formal solution of the RT equation we employ short characteristics with two-point algorithm. Using an implicit representation of the source function in the computation of the specific intensities, we compute and store the coefficients of the linear relations J=a+bS between the mean intensity J and the corresponding source function S. The use of iteration factors in the ‘local’ coefficients of these implicit relations in two ‘inward’ sweeps of 2D grid, along with the update of the source function in other two ‘outward’ sweeps leads to four times faster solution than the Jacobi’s one. Moreover, the update made in all four consecutive sweeps of the grid leads to an acceleration by a factor of 6-7 compared to the Jacobi iterative scheme.
NASA Astrophysics Data System (ADS)
Pauldrach, A. W. A.; Hoffmann, T. L.; Hultzsch, P. J. N.
2014-09-01
Context. In type Ia supernova (SN Ia) envelopes a huge number of lines of different elements overlap within their thermal Doppler widths, and this problem is exacerbated by the circumstance that up to 20% of these lines can have a line optical depth higher than 1. The stagnation of the lambda iteration in such optically thick cases is one of the fundamental physical problems inherent in the iterative solution of the non-LTE problem, and the failure of a lambda iteration to converge is a point of crucial importance whose physical significance must be understood completely. Aims: We discuss a general problem related to radiative transfer under the physical conditions of supernova ejecta that involves a failure of the usual non-LTE iteration scheme to converge when multiple strong opacities belonging to different physical transitions come together, similar to the well-known situation where convergence is impaired even when only a single process attains high optical depths. The convergence problem is independent of the chosen frequency and depth grid spacing, independent of whether the radiative transfer is solved in the comoving or observer's frame, and independent of whether a common complete-linearization scheme or a conventional accelerated lambda iteration (ALI) is used. The problem appears when all millions of line transitions required for a realistic description of SN Ia envelopes are treated in the frame of a comprehensive non-LTE model. The only solution to this problem is a complete-linearization approach that considers all ions of all elements simultaneously, or an adequate generalization of the established ALI technique that accounts for the mutual interaction of the strong spectral lines of different elements and which thereby unfreezes the "stuck" state of the iteration. Methods: The physics of the atmospheres of SN Ia are strongly affected by the high-velocity expansion of the ejecta, which dominates the formation of the spectra at all wavelength ranges
An accelerated subspace iteration for eigenvector derivatives
NASA Technical Reports Server (NTRS)
Ting, Tienko
1991-01-01
An accelerated subspace iteration method for calculating eigenvector derivatives has been developed. Factors affecting the effectiveness and the reliability of the subspace iteration are identified, and effective strategies concerning these factors are presented. The method has been implemented, and the results of a demonstration problem are presented.
Anderson Acceleration for Fixed-Point Iterations
Walker, Homer F.
2015-08-31
The purpose of this grant was to support research on acceleration methods for fixed-point iterations, with applications to computational frameworks and simulation problems that are of interest to DOE.
On the safety of ITER accelerators.
Li, Ge
2013-01-01
Three 1 MV/40A accelerators in heating neutral beams (HNB) are on track to be implemented in the International Thermonuclear Experimental Reactor (ITER). ITER may produce 500 MWt of power by 2026 and may serve as a green energy roadmap for the world. They will generate -1 MV 1 h long-pulse ion beams to be neutralised for plasma heating. Due to frequently occurring vacuum sparking in the accelerators, the snubbers are used to limit the fault arc current to improve ITER safety. However, recent analyses of its reference design have raised concerns. General nonlinear transformer theory is developed for the snubber to unify the former snubbers' different design models with a clear mechanism. Satisfactory agreement between theory and tests indicates that scaling up to a 1 MV voltage may be possible. These results confirm the nonlinear process behind transformer theory and map out a reliable snubber design for a safer ITER.
Accelerating an iterative process by explicit annihilation
NASA Technical Reports Server (NTRS)
Jespersen, D. C.; Buning, P. G.
1985-01-01
A slowly convergent stationary iterative process can be accelerated by explicitly annihilating (i.e., eliminating) the dominant eigenvector component of the error. The dominant eigenvalue or complex pair of eigenvalues can be estimated from the solution during the iteration. The corresponding eigenvector or complex pair of eigenvectors can then be annihilated by applying an explicit Richardson process over the basic iterative method. This can be done entirely in real arithmetic by analytically combining the complex conjugate annihilation steps. The technique is applied to an implicit algorithm for the calculation of two dimensional steady transonic flow over a circular cylinder using the equations of compressible inviscid gas dynamics. This demonstrates the use of explicit annihilation on a nonlinear problem.
Accelerating an iterative process by explicit annihilation
NASA Technical Reports Server (NTRS)
Jespersen, D. C.; Buning, P. G.
1983-01-01
A slowly convergent stationary iterative process can be accelerated by explicitly annihilating (i.e., eliminating) the dominant eigenvector component of the error. The dominant eigenvalue or complex pair of eigenvalues can be estimated from the solution during the iteration. The corresponding eigenvector or complex pair of eigenvectors can then be annihilated by applying an explicit Richardson process over the basic iterative method. This can be done entirely in real arithmetic by analytically combining the complex conjugate annihilation steps. The technique is applied to an implicit algorithm for the calculation of two dimensional steady transonic flow over a circular cylinder using the equations of compressible inviscid gas dynamics. This demonstrates the use of explicit annihilation on a nonlinear problem.
On the safety of ITER accelerators
Li, Ge
2013-01-01
Three 1 MV/40A accelerators in heating neutral beams (HNB) are on track to be implemented in the International Thermonuclear Experimental Reactor (ITER). ITER may produce 500 MWt of power by 2026 and may serve as a green energy roadmap for the world. They will generate −1 MV 1 h long-pulse ion beams to be neutralised for plasma heating. Due to frequently occurring vacuum sparking in the accelerators, the snubbers are used to limit the fault arc current to improve ITER safety. However, recent analyses of its reference design have raised concerns. General nonlinear transformer theory is developed for the snubber to unify the former snubbers' different design models with a clear mechanism. Satisfactory agreement between theory and tests indicates that scaling up to a 1 MV voltage may be possible. These results confirm the nonlinear process behind transformer theory and map out a reliable snubber design for a safer ITER. PMID:24008267
Status of the Development of the SINGAP Accelerator for ITER
Hemsworth, R. S.; Esch, H. P. L. de; Svensson, L.; Villecroze, F.
2007-08-10
The development of the Single Aperture, Single Gap 1 MV accelerator (SINGAP) is being carried out on the 1 MV test bed at the DRFC, CEA Cadarache, France. This paper reports on the latest performance achieved with the prototype, 'ITER-like' accelerator, 730 keV, 120 A/m2 D-, and of on-going measurements of the beam 'halo' fraction, {approx_equal}10%. It reviews the status and plans for future studies on D- production, and the observed 'dark current', and presents the basic physics design of a system that should cope with the {approx_equal}3 MW of electrons that would be co-accelerated out of the 1 MeV, 40 A, D- SINGAP accelerator proposed for the ITER neutral beam injectors.
Linear multifrequency-grey acceleration recast for preconditioned Krylov iterations
Morel, Jim E. Brian Yang, T.-Y.; Warsa, James S.
2007-11-10
The linear multifrequency-grey acceleration (LMFGA) technique is used to accelerate the iterative convergence of multigroup thermal radiation diffusion calculations in high energy density simulations. Although it is effective and efficient in one-dimensional calculations, the LMFGA method has recently been observed to significantly degrade under certain conditions in multidimensional calculations with large discontinuities in material properties. To address this deficiency, we recast the LMFGA method in terms of a preconditioned system that is solved with a Krylov method (LMFGK). Results are presented demonstrating that the new LMFGK method always requires fewer iterations than the original LMFGA method. The reduction in iteration count increases with both the size of the time step and the inhomogeneity of the problem. However, for reasons later explained, the LMFGK method can cost more per iteration than the LMFGA method, resulting in lower but comparable efficiency in problems with small time steps and weak inhomogeneities. In problems with large time steps and strong inhomogeneities, the LMFGK method is significantly more efficient than the LMFGA method.
Krylov iterative methods and synthetic acceleration for transport in binary statistical media
Fichtl, Erin D; Warsa, James S; Prinja, Anil K
2008-01-01
In particle transport applications there are numerous physical constructs in which heterogeneities are randomly distributed. The quantity of interest in these problems is the ensemble average of the flux, or the average of the flux over all possible material 'realizations.' The Levermore-Pomraning closure assumes Markovian mixing statistics and allows a closed, coupled system of equations to be written for the ensemble averages of the flux in each material. Generally, binary statistical mixtures are considered in which there are two (homogeneous) materials and corresponding coupled equations. The solution process is iterative, but convergence may be slow as either or both materials approach the diffusion and/or atomic mix limits. A three-part acceleration scheme is devised to expedite convergence, particularly in the atomic mix-diffusion limit where computation is extremely slow. The iteration is first divided into a series of 'inner' material and source iterations to attenuate the diffusion and atomic mix error modes separately. Secondly, atomic mix synthetic acceleration is applied to the inner material iteration and S{sup 2} synthetic acceleration to the inner source iterations to offset the cost of doing several inner iterations per outer iteration. Finally, a Krylov iterative solver is wrapped around each iteration, inner and outer, to further expedite convergence. A spectral analysis is conducted and iteration counts and computing cost for the new two-step scheme are compared against those for a simple one-step iteration, to which a Krylov iterative method can also be applied.
An accelerated iterative method for the dynamics of constrained multibody systems
NASA Astrophysics Data System (ADS)
Lee, Kisu
1993-01-01
An accelerated iterative method is suggested for the dynamic analysis of multibody systems consisting of interconnected rigid bodies. The Lagrange multipliers associated with the kinematic constraints are iteratively computed by the monotone reduction of the constraint error vector, and the resulting equations of motion are easily time-integrated by a well established ODE technique. The velocity and acceleration constraints as well as the position constraints are made to be satisfied at the joints at each time step. Exact solution is obtained without the time demanding procedures such as selection of the independent coordinates, decomposition of the constraint Jacobian matrix, and Newton Raphson iterations. An acceleration technique is employed for the faster convergence of the iterative scheme and the convergence analysis of the proposed iterative method is presented. Numerical solutions for the verification problems are presented to demonstrate the efficiency and accuracy of the suggested technique.
Accelerate OPC convergence with new iteration control methodology
NASA Astrophysics Data System (ADS)
Wang, Ching-Heng; Liu, Qingwei; Zhang, Liguo
2008-10-01
A dilemmatic trade-off that all OPC engineers are facing everyday is the convergence of the OPC result and the control of the OPC iteration times. Theoretically, infinite times of OPC iterations are needed to achieve a convergent and stable correction result. But actually there should always be a cut-off for the iteration time, for turnaround- time is always an important criteria for IC fabs. But considering the design layout becomes more complicated and pattern density becomes higher with the shrinkage of the critical dimension, fragmentation control during the OPC procedure is also becoming more and more sophisticated. Thus, to achieve a convergent correction result for all OPC fragments within limited correction iteration times now becomes a big challenge to OPC engineers. This work presents our study in a new OPC iteration control methodology. It can help to find an algorithm that always converges, and reduce the excessive use of parameter setting, commands and other involvement by the user. With this, we can reduce the run time required to obtain a convergent OPC solution.
Willert, Jeffrey; Taitano, William T.; Knoll, Dana
2014-09-15
In this note we demonstrate that using Anderson Acceleration (AA) in place of a standard Picard iteration can not only increase the convergence rate but also make the iteration more robust for two transport applications. We also compare the convergence acceleration provided by AA to that provided by moment-based acceleration methods. Additionally, we demonstrate that those two acceleration methods can be used together in a nested fashion. We begin by describing the AA algorithm. At this point, we will describe two application problems, one from neutronics and one from plasma physics, on which we will apply AA. We provide computational results which highlight the benefits of using AA, namely that we can compute solutions using fewer function evaluations, larger time-steps, and achieve a more robust iteration.
Iterative acceleration methods for Monte Carlo and deterministic criticality calculations
Urbatsch, T.J.
1995-11-01
If you have ever given up on a nuclear criticality calculation and terminated it because it took so long to converge, you might find this thesis of interest. The author develops three methods for improving the fission source convergence in nuclear criticality calculations for physical systems with high dominance ratios for which convergence is slow. The Fission Matrix Acceleration Method and the Fission Diffusion Synthetic Acceleration (FDSA) Method are acceleration methods that speed fission source convergence for both Monte Carlo and deterministic methods. The third method is a hybrid Monte Carlo method that also converges for difficult problems where the unaccelerated Monte Carlo method fails. The author tested the feasibility of all three methods in a test bed consisting of idealized problems. He has successfully accelerated fission source convergence in both deterministic and Monte Carlo criticality calculations. By filtering statistical noise, he has incorporated deterministic attributes into the Monte Carlo calculations in order to speed their source convergence. He has used both the fission matrix and a diffusion approximation to perform unbiased accelerations. The Fission Matrix Acceleration method has been implemented in the production code MCNP and successfully applied to a real problem. When the unaccelerated calculations are unable to converge to the correct solution, they cannot be accelerated in an unbiased fashion. A Hybrid Monte Carlo method weds Monte Carlo and a modified diffusion calculation to overcome these deficiencies. The Hybrid method additionally possesses reduced statistical errors.
Acceleration of iterative tomographic image reconstruction by reference-based back projection
NASA Astrophysics Data System (ADS)
Cheng, Chang-Chieh; Li, Ping-Hui; Ching, Yu-Tai
2016-03-01
The purpose of this paper is to design and implement an efficient iterative reconstruction algorithm for computational tomography. We accelerate the reconstruction speed of algebraic reconstruction technique (ART), an iterative reconstruction method, by using the result of filtered backprojection (FBP), a wide used algorithm of analytical reconstruction, to be an initial guess and the reference for the first iteration and each back projection stage respectively. Both two improvements can reduce the error between the forward projection of each iteration and the measurements. We use three methods of quantitative analysis, root-mean-square error (RMSE), peak signal to noise ratio (PSNR), and structural content (SC), to show that our method can reduce the number of iterations by more than half and the quality of the result is better than the original ART.
ACCELERATED MRI USING ITERATIVE NON-LOCAL SHRINKAGE
Mohsin, Yasir Q.; Ongie, Gregory; Jacob, Mathews
2015-01-01
We introduce a fast iterative non-local shrinkage algorithm to recover MRI data from undersampled Fourier measurements. This approach is enabled by the reformulation of current non-local schemes as an alternating algorithm to minimize a global criterion. The proposed algorithm alternates between a non-local shrinkage step and a quadratic subproblem. The resulting algorithm is observed to be considerably faster than current alternating non-local algorithms. We use efficient continuation strategies to minimize local minima issues. The comparisons of the proposed scheme with state-of-the-art regularization schemes show a considerable reduction in alias artifacts and preservation of edges. PMID:25570265
An accelerated and convergent iterative algorithm in image reconstruction
NASA Astrophysics Data System (ADS)
Yan, Jianhua; Yu, Jun
2007-05-01
Positron emission tomography (PET) is becoming increasingly important in the field of medicine and biology. The maximum-likelihood expectation-maximization (ML-EM) algorithm is becoming more important than filtered back-projection (FBP) algorithm which can incorporate various physical models into image reconstruction scheme. However, ML-EM converges slowly. In this paper, we propose a new algorithm named AC-ML-EM (accelerated and convergent maximum likelihood expectation maximization) by introducing gradually decreasing correction factor into ML-EM. AC-ML-EM has a higher speed of convergence. Through the experiments of computer simulated phantom data and real phantom data, AC-ML-EM is shown faster and better quantitatively than conventional ML-EM algorithm.
Detailed design optimization of the MITICA negative ion accelerator in view of the ITER NBI
NASA Astrophysics Data System (ADS)
Agostinetti, P.; Aprile, D.; Antoni, V.; Cavenago, M.; Chitarin, G.; de Esch, H. P. L.; De Lorenzi, A.; Fonnesu, N.; Gambetta, G.; Hemsworth, R. S.; Kashiwagi, M.; Marconato, N.; Marcuzzi, D.; Pilan, N.; Sartori, E.; Serianni, G.; Singh, M.; Sonato, P.; Spada, E.; Toigo, V.; Veltri, P.; Zaccaria, P.
2016-01-01
The ITER Neutral Beam Test Facility (PRIMA) is presently under construction at Consorzio RFX (Padova, Italy). PRIMA includes two experimental devices: an ITER-size ion source with low voltage extraction, called SPIDER, and the full prototype of the whole ITER Heating Neutral Beams (HNBs), called MITICA. The purpose of MITICA is to demonstrate that all operational parameters of the ITER HNB accelerator can be experimentally achieved, thus establishing a large step forward in the performances of neutral beam injectors in comparison with the present experimental devices. The design of the MITICA extractor and accelerator grids, here described in detail, was developed using an integrated approach, taking into consideration at the same time all the relevant physics and engineering aspects. Particular care was taken also to support and validate the design on the basis of the expertise and experimental data made available by the collaborating neutral beam laboratories of CEA, IPP, CCFE, NIFS and JAEA. Considering the operational requirements and the other physics constraints of the ITER HNBs, the whole design has been thoroughly optimized and improved. Furthermore, specific innovative concepts have been introduced.
Status of the 1 MeV Accelerator Design for ITER NBI
Kuriyama, M.; Boilson, D.; Hemsworth, R.; Svensson, L.; Graceffa, J.; Schunke, B.; Decamps, H.; Tanaka, M.; Bonicelli, T.; Masiello, A.
2011-09-26
The beam source of neutral beam heating/current drive system for ITER is needed to accelerate the negative ion beam of 40A with D{sup -} at 1 MeV for 3600 sec. In order to realize the beam source, design and R and D works are being developed in many institutions under the coordination of ITER organization. The development of the key issues of the ion source including source plasma uniformity, suppression of co-extracted electron in D beam operation and also after the long beam duration time of over a few 100 sec, is progressed mainly in IPP with the facilities of BATMAN, MANITU and RADI. In the near future, ELISE, that will be tested the half size of the ITER ion source, will start the operation in 2011, and then SPIDER, which demonstrates negative ion production and extraction with the same size and same structure as the ITER ion source, will start the operation in 2014 as part of the NBTF. The development of the accelerator is progressed mainly in JAEA with the MeV test facility, and also the computer simulation of beam optics also developed in JAEA, CEA and RFX. The full ITER heating and current drive beam performance will be demonstrated in MITICA, which will start operation in 2016 as part of the NBTF.
Status of the 1 MeV Accelerator Design for ITER NBI
NASA Astrophysics Data System (ADS)
Kuriyama, M.; Boilson, D.; Hemsworth, R.; Svensson, L.; Graceffa, J.; Schunke, B.; Decamps, H.; Tanaka, M.; Bonicelli, T.; Masiello, A.; Bigi, M.; Chitarin, G.; Luchetta, A.; Marcuzzi, D.; Pasqualotto, R.; Pomaro, N.; Serianni, G.; Sonato, P.; Toigo, V.; Zaccaria, P.; Kraus, W.; Franzen, P.; Heinemann, B.; Inoue, T.; Watanabe, K.; Kashiwagi, M.; Taniguchi, M.; Tobari, H.; De Esch, H.
2011-09-01
The beam source of neutral beam heating/current drive system for ITER is needed to accelerate the negative ion beam of 40A with D- at 1 MeV for 3600 sec. In order to realize the beam source, design and R&D works are being developed in many institutions under the coordination of ITER organization. The development of the key issues of the ion source including source plasma uniformity, suppression of co-extracted electron in D beam operation and also after the long beam duration time of over a few 100 sec, is progressed mainly in IPP with the facilities of BATMAN, MANITU and RADI. In the near future, ELISE, that will be tested the half size of the ITER ion source, will start the operation in 2011, and then SPIDER, which demonstrates negative ion production and extraction with the same size and same structure as the ITER ion source, will start the operation in 2014 as part of the NBTF. The development of the accelerator is progressed mainly in JAEA with the MeV test facility, and also the computer simulation of beam optics also developed in JAEA, CEA and RFX. The full ITER heating and current drive beam performance will be demonstrated in MITICA, which will start operation in 2016 as part of the NBTF.
lambda lambda. hypernuclei and the. lambda lambda. interaction
Bodmer, A.R.; Usmani, Q.N.
1986-01-01
Variational calculations of ..cap alpha..-cluster models for /sup 6//sub ..lambda lambda../He, /sup 9//sub ..lambda lambda../Be have been made. These calculations require a knowledge of the ..cap alpha lambda.. potential which is obtained in several ways including the use of five-body Monte Carlo (MC) calculations of /sup 5//sub ..lambda../He. We discuss the ..lambda lambda.. interaction strengths and the relation between the /sup 6//sub ..lambda lambda../He and /sup 10//sub ..lambda lambda../Be binding energies and, in particular, the dependence of these on the ..cap alpha lambda.. potential. For all our ..cap alpha lambda.. potentials the binding energy of /sup 6//sub ..lambda lambda../He predicted from /sup 10//sub ..lambda lambda../Be is 1 MeV or more below the experimental value. A brief discussion is given of the implication of the phenomenological strength of ..lambda lambda.. interaction we obtain and also the implication of ..lambda lambda.. hypernuclei for the H-dibaryon. 19 refs., 2 figs., 1 tab.
NASA Astrophysics Data System (ADS)
Iotti, Robert
2015-04-01
ITER is an international experimental facility being built by seven Parties to demonstrate the long term potential of fusion energy. The ITER Joint Implementation Agreement (JIA) defines the structure and governance model of such cooperation. There are a number of necessary conditions for such international projects to be successful: a complete design, strong systems engineering working with an agreed set of requirements, an experienced organization with systems and plans in place to manage the project, a cost estimate backed by industry, and someone in charge. Unfortunately for ITER many of these conditions were not present. The paper discusses the priorities in the JIA which led to setting up the project with a Central Integrating Organization (IO) in Cadarache, France as the ITER HQ, and seven Domestic Agencies (DAs) located in the countries of the Parties, responsible for delivering 90%+ of the project hardware as Contributions-in-Kind and also financial contributions to the IO, as ``Contributions-in-Cash.'' Theoretically the Director General (DG) is responsible for everything. In practice the DG does not have the power to control the work of the DAs, and there is not an effective management structure enabling the IO and the DAs to arbitrate disputes, so the project is not really managed, but is a loose collaboration of competing interests. Any DA can effectively block a decision reached by the DG. Inefficiencies in completing design while setting up a competent organization from scratch contributed to the delays and cost increases during the initial few years. So did the fact that the original estimate was not developed from industry input. Unforeseen inflation and market demand on certain commodities/materials further exacerbated the cost increases. Since then, improvements are debatable. Does this mean that the governance model of ITER is a wrong model for international scientific cooperation? I do not believe so. Had the necessary conditions for success
Voltage holding study of 1 MeV accelerator for ITER neutral beam injector.
Taniguchi, M; Kashiwagi, M; Umeda, N; Dairaku, M; Takemoto, J; Tobari, H; Tsuchida, K; Yamanaka, H; Watanabe, K; Kojima, A; Hanada, M; Sakamoto, K; Inoue, T
2012-02-01
Voltage holding test on MeV accelerator indicated that sustainable voltage was a half of that of ideal quasi-Rogowski electrode. It was suggested that the emission of the clumps is enhanced by a local electric field concentration, which leads to discharge initiation at lower voltage. To reduce the electric field concentration in the MeV accelerator, gaps between the grid supports were expanded and curvature radii at the support corners were increased. After the modifications, the accelerator succeeded in sustaining -1 MV in vacuum without beam acceleration. However, the beam energy was still limited at a level of 900 keV with a beam current density of 150 A∕m(2) (346 mA) where the 3 × 5 apertures were used. Measurement of the beam profile revealed that deflection of the H(-) ions was large and a part of the H(-) ions was intercepted at the acceleration grid. This causes high heat load on the grids and the breakdowns during beam acceleration. To suppress the direct interception, new grid system was designed with proper aperture displacement based on a 3D beam trajectory analysis. As the result, the beam deflection was compensated and the voltage holding during the beam acceleration was improved. Beam parameter of the MeV accelerator was increased to 980 keV, 185 A∕m(2) (427 mA), which is close to the requirement of ITER accelerator (1 MeV, 200 A∕m(2)).
Lorber, A.A.; Carey, G.F.; Bova, S.W.; Harle, C.H.
1996-12-31
The connection between the solution of linear systems of equations by iterative methods and explicit time stepping techniques is used to accelerate to steady state the solution of ODE systems arising from discretized PDEs which may involve either physical or artificial transient terms. Specifically, a class of Runge-Kutta (RK) time integration schemes with extended stability domains has been used to develop recursion formulas which lead to accelerated iterative performance. The coefficients for the RK schemes are chosen based on the theory of Chebyshev iteration polynomials in conjunction with a local linear stability analysis. We refer to these schemes as Chebyshev Parameterized Runge Kutta (CPRK) methods. CPRK methods of one to four stages are derived as functions of the parameters which describe an ellipse {Epsilon} which the stability domain of the methods is known to contain. Of particular interest are two-stage, first-order CPRK and four-stage, first-order methods. It is found that the former method can be identified with any two-stage RK method through the correct choice of parameters. The latter method is found to have a wide range of stability domains, with a maximum extension of 32 along the real axis. Recursion performance results are presented below for a model linear convection-diffusion problem as well as non-linear fluid flow problems discretized by both finite-difference and finite-element methods.
Voltage holding study of 1 MeV accelerator for ITER neutral beam injector
Taniguchi, M.; Kashiwagi, M.; Umeda, N.; Dairaku, M.; Takemoto, J.; Tobari, H.; Tsuchida, K.; Yamanaka, H.; Watanabe, K.; Kojima, A.; Hanada, M.; Sakamoto, K.; Inoue, T.
2012-02-15
Voltage holding test on MeV accelerator indicated that sustainable voltage was a half of that of ideal quasi-Rogowski electrode. It was suggested that the emission of the clumps is enhanced by a local electric field concentration, which leads to discharge initiation at lower voltage. To reduce the electric field concentration in the MeV accelerator, gaps between the grid supports were expanded and curvature radii at the support corners were increased. After the modifications, the accelerator succeeded in sustaining -1 MV in vacuum without beam acceleration. However, the beam energy was still limited at a level of 900 keV with a beam current density of 150 A/m{sup 2} (346 mA) where the 3 x 5 apertures were used. Measurement of the beam profile revealed that deflection of the H{sup -} ions was large and a part of the H{sup -} ions was intercepted at the acceleration grid. This causes high heat load on the grids and the breakdowns during beam acceleration. To suppress the direct interception, new grid system was designed with proper aperture displacement based on a 3D beam trajectory analysis. As the result, the beam deflection was compensated and the voltage holding during the beam acceleration was improved. Beam parameter of the MeV accelerator was increased to 980 keV, 185 A/m{sup 2} (427 mA), which is close to the requirement of ITER accelerator (1 MeV, 200 A/m{sup 2}).
NASA Astrophysics Data System (ADS)
Azmy, Y. Y.
1999-06-01
We propose preconditioning as a viable acceleration scheme for the inner iterations of transport calculations in slab geometry. In particular we develop Adjacent-Cell Preconditioners (AP) that have the same coupling stencil as cell-centered diffusion schemes. For lowest order methods, e.g., Diamond Difference, Step, and 0-order Nodal Integral Method (0NIM), cast in a Weighted Diamond Difference (WDD) form, we derive AP for thick (KAP) and thin (NAP) cells that for model problems are unconditionally stable and efficient. For the First-Order Nodal Integral Method (1NIM) we derive a NAP that possesses similarly excellent spectral properties for model problems. [Note that the order of NIM refers to the truncated order of the local expansion of the cell and edge fluxes in Legendre series.] The two most attractive features of our new technique are: (1) its cell-centered coupling stencil, which makes it more adequate for extension to multidimensional, higher order situations than the standard edge-centered or point-centered Diffusion Synthetic Acceleration (DSA) methods; and (2) its decreasing spectral radius with increasing cell thickness to the extent that immediate pointwise convergence, i.e., in one iteration, can be achieved for problems with sufficiently thick cells. We implemented these methods, augmented with appropriate boundary conditions and mixing formulas for material heterogeneities, in the test code AP1D that we use to successfully verify the analytical spectral properties for homogeneous problems. Furthermore, we conduct numerical tests to demonstrate the robustness of the KAP and NAP in the presence of sharp mesh or material discontinuities. We show that the AP for WDD is highly resilient to such discontinuities, but for 1NIM a few cases occur in which the scheme does not converge; however, when it converges, AP greatly reduces the number of iterations required to achieve convergence.
Azmy, Y.Y.
1999-06-10
The author proposes preconditioning as a viable acceleration scheme for the inner iterations of transport calculations in slab geometry. In particular he develops Adjacent-Cell Preconditioners (AP) that have the same coupling stencil as cell-centered diffusion schemes. For lowest order methods, e.g., Diamond Difference, Step, and 0-order Nodal Integral Method (ONIM), cast in a Weighted Diamond Difference (WDD) form, he derives AP for thick (KAP) and thin (NAP) cells that for model problems are unconditionally stable and efficient. For the First-Order Nodal Integral Method (INIM) he derives a NAP that possesses similarly excellent spectral properties for model problems. The two most attractive features of the new technique are:(1) its cell-centered coupling stencil, which makes it more adequate for extension to multidimensional, higher order situations than the standard edge-centered or point-centered Diffusion Synthetic Acceleration (DSA) methods; and (2) its decreasing spectral radius with increasing cell thickness to the extent that immediate pointwise convergence, i.e., in one iteration, can be achieved for problems with sufficiently thick cells. He implemented these methods, augmented with appropriate boundary conditions and mixing formulas for material heterogeneities, in the test code APID that he uses to successfully verify the analytical spectral properties for homogeneous problems. Furthermore, he conducts numerical tests to demonstrate the robustness of the KAP and NAP in the presence of sharp mesh or material discontinuities. He shows that the AP for WDD is highly resilient to such discontinuities, but for INIM a few cases occur in which the scheme does not converge; however, when it converges, AP greatly reduces the number of iterations required to achieve convergence.
Lin, Lin; Yang, Chao
2013-10-28
We discuss techniques for accelerating the self consistent field (SCF) iteration for solving the Kohn-Sham equations. These techniques are all based on constructing approximations to the inverse of the Jacobian associated with a fixed point map satisfied by the total potential. They can be viewed as preconditioners for a fixed point iteration. We point out different requirements for constructing preconditioners for insulating and metallic systems respectively, and discuss how to construct preconditioners to keep the convergence rate of the fixed point iteration independent of the size of the atomistic system. We propose a new preconditioner that can treat insulating and metallic system in a unified way. The new preconditioner, which we call an elliptic preconditioner, is constructed by solving an elliptic partial differential equation. The elliptic preconditioner is shown to be more effective in accelerating the convergence of a fixed point iteration than the existing approaches for large inhomogeneous systems at low temperature.
Highly accelerated cardiac MRI using iterative SENSE reconstruction: initial clinical experience.
Allen, Bradley D; Carr, Maria; Botelho, Marcos P F; Rahsepar, Amir Ali; Markl, Michael; Zenge, Michael O; Schmidt, Michaela; Nadar, Mariappan S; Spottiswoode, Bruce; Collins, Jeremy D; Carr, James C
2016-06-01
To evaluate the qualitative and quantitative performance of an accelerated cardiovascular MRI (CMR) protocol that features iterative SENSE reconstruction and spatio-temporal L1-regularization (IS SENSE). Twenty consecutively recruited patients and 9 healthy volunteers were included. 2D steady state free precession cine images including 3-chamber, 4-chamber, and short axis slices were acquired using standard parallel imaging (GRAPPA, acceleration factor = 2), spatio-temporal undersampled TSENSE (acceleration factor = 4), and IS SENSE techniques (acceleration factor = 4). Acquisition times, quantitative cardiac functional parameters, wall motion abnormalities (WMA), and qualitative performance (scale: 1-poor to 5-excellent for overall image quality, noise, and artifact) were compared. Breath-hold times for IS SENSE (3.0 ± 0.6 s) and TSENSE (3.3 ± 0.6) were both reduced relative to GRAPPA (8.4 ± 1.7 s, p < 0.001). No difference in quantitative cardiac function was present between the three techniques (p = 0.89 for ejection fraction). GRAPPA and IS SENSE had similar image quality (4.7 ± 0.4 vs. 4.5 ± 0.6, p = 0.09) while, both techniques were superior to TSENSE (quality: 4.1 ± 0.7, p < 0.001). GRAPPA WMA agreement with IS SENSE was good (κ > 0.60, p < 0.001), while agreement with TSENSE was poor (κ < 0.40, p < 0.001). IS SENSE is a viable clinical CMR acceleration approach to reduce acquisition times while maintaining satisfactory qualitative and quantitative performance. PMID:26894256
GPU-accelerated regularized iterative reconstruction for few-view cone beam CT
Matenine, Dmitri; Goussard, Yves
2015-04-15
Purpose: The present work proposes an iterative reconstruction technique designed for x-ray transmission computed tomography (CT). The main objective is to provide a model-based solution to the cone-beam CT reconstruction problem, yielding accurate low-dose images via few-views acquisitions in clinically acceptable time frames. Methods: The proposed technique combines a modified ordered subsets convex (OSC) algorithm and the total variation minimization (TV) regularization technique and is called OSC-TV. The number of subsets of each OSC iteration follows a reduction pattern in order to ensure the best performance of the regularization method. Considering the high computational cost of the algorithm, it is implemented on a graphics processing unit, using parallelization to accelerate computations. Results: The reconstructions were performed on computer-simulated as well as human pelvic cone-beam CT projection data and image quality was assessed. In terms of convergence and image quality, OSC-TV performs well in reconstruction of low-dose cone-beam CT data obtained via a few-view acquisition protocol. It compares favorably to the few-view TV-regularized projections onto convex sets (POCS-TV) algorithm. It also appears to be a viable alternative to full-dataset filtered backprojection. Execution times are of 1–2 min and are compatible with the typical clinical workflow for nonreal-time applications. Conclusions: Considering the image quality and execution times, this method may be useful for reconstruction of low-dose clinical acquisitions. It may be of particular benefit to patients who undergo multiple acquisitions by reducing the overall imaging radiation dose and associated risks.
Long pulse acceleration of MeV class high power density negative H{sup −} ion beam for ITER
Umeda, N. Kojima, A.; Kashiwagi, M.; Tobari, H.; Hiratsuka, J.; Watanabe, K.; Dairaku, M.; Yamanaka, H.; Hanada, M.
2015-04-08
R and D of high power density negative ion beam acceleration has been carried out at MeV test facility in JAEA to realize ITER neutral beam accelerator. The main target is H{sup −} ion beam acceleration up to 1 MeV with 200 A/m{sup 2} for 60 s whose pulse length is the present facility limit. For long pulse acceleration at high power density, new extraction grid (EXG) has been developed with high cooling capability, which electron suppression magnet is placed under cooling channel similar to ITER. In addition, aperture size of electron suppression grid (ESG) is enlarged from 14 mm to 16 mm to reduce direct interception on the ESG and emission of secondary electron which leads to high heat load on the upstream acceleration grid. By enlarging ESG aperture, beam current increased 10 % at high current beam and total acceleration grid heat load reduced from 13 % to 10 % of input power at long pulse beam. In addition, heat load by back stream positive ion into the EXG is measured for the first time and is estimated as 0.3 % of beam power, while heat load by back stream ion into the source chamber is estimated as 3.5 ~ 4.0 % of beam power. Beam acceleration up to 60 s which is the facility limit, has achieved at 683 keV, 100 A/m{sup 2} of negative ion beam, whose energy density increases two orders of magnitude since 2011.
Dana A. Knoll; H. Park; Kord Smith
2011-02-01
The use of the Jacobian-free Newton-Krylov (JFNK) method within the context of nonlinear diffusion acceleration (NDA) of source iteration is explored. The JFNK method is a synergistic combination of Newton's method as the nonlinear solver and Krylov methods as the linear solver. JFNK methods do not form or store the Jacobian matrix, and Newton's method is executed via probing the nonlinear discrete function to approximate the required matrix-vector products. Current application of NDA relies upon a fixed-point, or Picard, iteration to resolve the nonlinearity. We show that the JFNK method can be used to replace this Picard iteration with a Newton iteration. The Picard linearization is retained as a preconditioner. We show that the resulting JFNK-NDA capability provides benefit in some regimes. Furthermore, we study the effects of a two-grid approach, and the required intergrid transfers when the higher-order transport method is solved on a fine mesh compared to the low-order acceleration problem.
NASA Astrophysics Data System (ADS)
Rosa, Massimiliano
We have derived expressions for the elements of the matrix representing a certain angular (SN) and spatial discretized form of the neutron integral transport operator. This is the transport operator that if directly inverted on the once-collided fixed particle source produces, without the need for an iterative procedure, the converged limit of the scalar fluxes for the iterative procedure. The asymptotic properties of this operator's elements have then been investigated in homogeneous and periodically heterogeneous limits in one-dimensional and two-dimensional geometries. The thesis covers the results obtained from this asymptotic study of the matrix structure of the discrete integral transport operator and illustrates how they relate to the iterative acceleration of neutral particle transport methods. Specifically, it will be shown that in one-dimensional problems (both homogeneous and periodically heterogeneous) and homogeneous two-dimensional problems, containing optically thick cells, the discrete integral transport operator acquires a sparse matrix structure, implying a strong local coupling of a cell-averaged scalar flux only with its nearest Cartesian neighbors. These results provide further insight into the excellent convergence properties of diffusion-based acceleration schemes for this broad class of transport problems. In contrast, the results of the asymptotic analysis for two-dimensional periodically heterogeneous problems point to a sparse but non-local matrix structure due to long-range coupling of a cell's average flux with its neighboring cells, independent of the distance between the cells in the spatial mesh. The latter results indicate that cross-derivative coupling, namely coupling of a cell's average flux to its diagonal neighbors, is of the same order as self-coupling and coupling with its first Cartesian neighbors. Hence they substantiate the conjecture that the loss of robustness of diffusion-based acceleration schemes, in particular of the
Pratapa, Phanisri P.; Suryanarayana, Phanish; Pask, John E.
2015-12-01
We employ Anderson extrapolation to accelerate the classical Jacobi iterative method for large, sparse linear systems. Specifically, we utilize extrapolation at periodic intervals within the Jacobi iteration to develop the Alternating Anderson–Jacobi (AAJ) method. We verify the accuracy and efficacy of AAJ in a range of test cases, including nonsymmetric systems of equations. We demonstrate that AAJ possesses a favorable scaling with system size that is accompanied by a small prefactor, even in the absence of a preconditioner. In particular, we show that AAJ is able to accelerate the classical Jacobi iteration by over four orders of magnitude, with speed-upsmore » that increase as the system gets larger. Moreover, we find that AAJ significantly outperforms the Generalized Minimal Residual (GMRES) method in the range of problems considered here, with the relative performance again improving with size of the system. As a result, the proposed method represents a simple yet efficient technique that is particularly attractive for large-scale parallel solutions of linear systems of equations.« less
Pratapa, Phanisri P.; Suryanarayana, Phanish; Pask, John E.
2015-12-01
We employ Anderson extrapolation to accelerate the classical Jacobi iterative method for large, sparse linear systems. Specifically, we utilize extrapolation at periodic intervals within the Jacobi iteration to develop the Alternating Anderson–Jacobi (AAJ) method. We verify the accuracy and efficacy of AAJ in a range of test cases, including nonsymmetric systems of equations. We demonstrate that AAJ possesses a favorable scaling with system size that is accompanied by a small prefactor, even in the absence of a preconditioner. In particular, we show that AAJ is able to accelerate the classical Jacobi iteration by over four orders of magnitude, with speed-ups that increase as the system gets larger. Moreover, we find that AAJ significantly outperforms the Generalized Minimal Residual (GMRES) method in the range of problems considered here, with the relative performance again improving with size of the system. As a result, the proposed method represents a simple yet efficient technique that is particularly attractive for large-scale parallel solutions of linear systems of equations.
Mizuno, T; Taniguchi, M; Kashiwagi, M; Umeda, N; Tobari, H; Watanabe, K; Dairaku, M; Sakamoto, K; Inoue, T
2010-02-01
Heat load on acceleration grids by secondary particles such as electrons, neutrals, and positive ions, is a key issue for long pulse acceleration of negative ion beams. Complicated behaviors of the secondary particles in multiaperture, multigrid (MAMuG) accelerator have been analyzed using electrostatic accelerator Monte Carlo code. The analytical result is compared to experimental one obtained in a long pulse operation of a MeV accelerator, of which second acceleration grid (A2G) was removed for simplification of structure. The analytical results show that relatively high heat load on the third acceleration grid (A3G) since stripped electrons were deposited mainly on A3G. This heat load on the A3G can be suppressed by installing the A2G. Thus, capability of MAMuG accelerator is demonstrated for suppression of heat load due to secondary particles by the intermediate grids.
Accelerating the weighted histogram analysis method by direct inversion in the iterative subspace
Zhang, Cheng; Lai, Chun-Liang; Pettitt, B. Montgomery
2016-01-01
The weighted histogram analysis method (WHAM) for free energy calculations is a valuable tool to produce free energy differences with the minimal errors. Given multiple simulations, WHAM obtains from the distribution overlaps the optimal statistical estimator of the density of states, from which the free energy differences can be computed. The WHAM equations are often solved by an iterative procedure. In this work, we use a well-known linear algebra algorithm which allows for more rapid convergence to the solution. We find that the computational complexity of the iterative solution to WHAM and the closely-related multiple Bennett acceptance ratio (MBAR) method can be improved by using the method of direct inversion in the iterative subspace. We give examples from a lattice model, a simple liquid and an aqueous protein solution. PMID:27453632
Long-pulse beam acceleration of MeV-class H(-) ion beams for ITER NB accelerator.
Umeda, N; Kashiwagi, M; Taniguchi, M; Tobari, H; Watanabe, K; Dairaku, M; Yamanaka, H; Inoue, T; Kojima, A; Hanada, M
2014-02-01
In order to realize neutral beam systems in International Thermonuclear Experimental Reactor whose target is to produce a 1 MeV, 200 A/m(2) during 3600 s D(-) ion beam, the electrostatic five-stages negative ion accelerator so-called "MeV accelerator" has been developed at Japan Atomic Energy Agency. To extend pulse length, heat load of the acceleration grids was reduced by controlling the ion beam trajectory. Namely, the beam deflection due to the residual magnetic field of filter magnet was suppressed with the newly developed extractor with a 0.5 mm off-set aperture displacement. The new extractor improved the deflection angle from 6 mrad to 1 mrad, resulting in the reduction of direct interception of negative ions from 23% to 15% of the total acceleration power, respectively. As a result, the pulse length of 130 A/m(2), 881 keV H(-) ion beam has been successfully extended from a previous value of 0.4 s to 8.7 s. This is the first long pulse negative ion beam acceleration over 100 MW/m(2).
Fast iterative image reconstruction using sparse matrix factorization with GPU acceleration
NASA Astrophysics Data System (ADS)
Zhou, Jian; Qi, Jinyi
2011-03-01
Statistically based iterative approaches for image reconstruction have gained much attention in medical imaging. An accurate system matrix that defines the mapping from the image space to the data space is the key to high-resolution image reconstruction. However, an accurate system matrix is often associated with high computational cost and huge storage requirement. Here we present a method to address this problem by using sparse matrix factorization and parallel computing on a graphic processing unit (GPU).We factor the accurate system matrix into three sparse matrices: a sinogram blurring matrix, a geometric projection matrix, and an image blurring matrix. The sinogram blurring matrix models the detector response. The geometric projection matrix is based on a simple line integral model. The image blurring matrix is to compensate for the line-of-response (LOR) degradation due to the simplified geometric projection matrix. The geometric projection matrix is precomputed, while the sinogram and image blurring matrices are estimated by minimizing the difference between the factored system matrix and the original system matrix. The resulting factored system matrix has much less number of nonzero elements than the original system matrix and thus substantially reduces the storage and computation cost. The smaller size also allows an efficient implement of the forward and back projectors on GPUs, which have limited amount of memory. Our simulation studies show that the proposed method can dramatically reduce the computation cost of high-resolution iterative image reconstruction. The proposed technique is applicable to image reconstruction for different imaging modalities, including x-ray CT, PET, and SPECT.
NASA Astrophysics Data System (ADS)
Czajkowski, Michael
2014-06-01
There is an explosion in the quantity and quality of IMINT data being captured in Intelligence Surveillance and Reconnaissance (ISR) today. While automated exploitation techniques involving computer vision are arriving, only a few architectures can manage both the storage and bandwidth of large volumes of IMINT data and also present results to analysts quickly. Lockheed Martin Advanced Technology Laboratories (ATL) has been actively researching in the area of applying Big Data cloud computing techniques to computer vision applications. This paper presents the results of this work in adopting a Lambda Architecture to process and disseminate IMINT data using computer vision algorithms. The approach embodies an end-to-end solution by processing IMINT data from sensors to serving information products quickly to analysts, independent of the size of the data. The solution lies in dividing up the architecture into a speed layer for low-latent processing and a batch layer for higher quality answers at the expense of time, but in a robust and fault-tolerant way. This approach was evaluated using a large corpus of IMINT data collected by a C-130 Shadow Harvest sensor over Afghanistan from 2010 through 2012. The evaluation data corpus included full motion video from both narrow and wide area field-of-views. The evaluation was done on a scaled-out cloud infrastructure that is similar in composition to those found in the Intelligence Community. The paper shows experimental results to prove the scalability of the architecture and precision of its results using a computer vision algorithm designed to identify man-made objects in sparse data terrain.
Acceleration of iterative Navier-Stokes solvers on graphics processing units
NASA Astrophysics Data System (ADS)
Tomczak, Tadeusz; Zadarnowska, Katarzyna; Koza, Zbigniew; Matyka, Maciej; Mirosław, Łukasz
2013-04-01
While new power-efficient computer architectures exhibit spectacular theoretical peak performance, they require specific conditions to operate efficiently, which makes porting complex algorithms a challenge. Here, we report results of the semi-implicit method for pressure linked equations (SIMPLE) and the pressure implicit with operator splitting (PISO) methods implemented on the graphics processing unit (GPU). We examine the advantages and disadvantages of the full porting over a partial acceleration of these algorithms run on unstructured meshes. We found that the full-port strategy requires adjusting the internal data structures to the new hardware and proposed a convenient format for storing internal data structures on GPUs. Our implementation is validated on standard steady and unsteady problems and its computational efficiency is checked by comparing its results and run times with those of some standard software (OpenFOAM) run on central processing unit (CPU). The results show that a server-class GPU outperforms a server-class dual-socket multi-core CPU system running essentially the same algorithm by up to a factor of 4.
Beam optics in a MeV-class multi-aperture multi-grid accelerator for the ITER neutral beam injector.
Kashiwagi, M; Taniguchi, M; Umeda, N; de Esch, H P L; Grisham, L R; Boilson, D; Hemsworth, R S; Tanaka, M; Tobari, H; Watanabe, K; Inoue, T
2012-02-01
In a multi-aperture multi-grid accelerator of the ITER neutral beam injector, the beamlets are deflected due to space charge repulsion between beamlets and beam groups, and also due to magnetic field. Moreover, the beamlet deflection is influenced by electric field distortion generated by grid support structure. Such complicated beamlet deflections and the compensations have been examined utilizing a three-dimensional beam analysis. The space charge repulsion and the influence by the grid support structure were studied in a 1∕4 model of the accelerator including 320 beamlets. Beamlet deflection due to the magnetic field was studied by a single beamlet model. As the results, compensation methods of the beamlet deflection were designed, so as to utilize a metal bar (so-called field shaping plate) of 1 mm thick beneath the electron suppression grid (ESG), and an aperture offset of 1 mm in the ESG.
{lambda}(1520) {yields} {lambda}{gamma} Radiative-Decay Width
Vavilov, D.V.; Antipov, Yu.M.; Artamonov, A.V.; Batarin, V.A.; Victorov, V.A.; Golovkin, S.V.; Gorin, Yu.P.; Eroshin, O.V.; Kozhevnikov, A.P.; Konstantinov, A.S.; Kubarovsky, V.P.; Kurshetsov, V.F.; Landsberg, L.G.; Leontiev, V.M.; Molchanov, V.V.; Mukhin, V.A.; Patalakha, D.I.; Petrenko, S.V.; Petrukhin, A.I.; Kolganov, V.Z.
2005-03-01
The radiative decay {lambda}(1520) {yields} {lambda}{gamma} was recorded in the exclusive reaction p + N {yields} {lambda}(1520)K{sup +} + N at the SPHINX facility. The branching ratio for this decay and the corresponding partial width were found to be, respectively, Br[{lambda}(1520) {yields} {lambda}{gamma}] = (1.02 {+-} 0.21) x 10{sup -2} and {gamma}[{lambda}(1520) {yields} {lambda}{gamma}] = 159 {+-} 35 keV (the quoted errors are purely statistical, the systematic errors being within 15%)
Olivas, Alexander Raymond, Jr.; /Colorado U.
2005-11-16
The decays of B{sup 0} mesons to hadronic final states remains a rich area of physics on BaBar. Not only do the c{bar c}-K final states (e.g. B{sup 0} {yields} {psi}(2S)K{sup 0}) allow for the measurement of CP Violation, but the branching fractions provide a sensitive test of the theoretical methods used to account for low energy non-perturbative QCD effects. They present the measurement of the branching fraction for the decay B{sup 0} {yields} {psi}(2S)K{sub s}. The data set consists of 88.8 {+-} 1.0 x 10{sup 6} B{bar b} pairs collected on the e{sup +}e{sup -} {yields} {Upsilon}(4S) resonance on BaBar/PEP-II at the Stanford Linear Accelerator Center (SLAC). This analysis features a modification of present cuts, with respect to those published so far on BaBar, on the K{sub S} {yields} {pi}{sup +}{pi}{sup -} and {psi}(2S) {yields} J/{psi}{pi}{sup +}{pi}{sup -} which aim at reducing the background while keeping the signal intact. Various data selection criteria are studied for the lepton modes (e{sup +}e{sup -} and {mu}{sup +}{mu}{sup -}) of the J/{psi} and {psi}(2S) to improve signal purity as well as study the stability of the resultant branching fractions.
NASA Technical Reports Server (NTRS)
Wagner, C. A.
1971-01-01
An attempt has been made to find a secular drift in lambda sub 2,2, or the phase of the low order and degree portion of the geogravity field. This portion may be associated with mass anomalies near the core-mantle boundary. From the geomagnetic evidence, such anomalies might have westward drifts on the order of 0.5 degrees/year. Tracking data on 8 synchronous satellite over a period of 6 years were examined for residual accelerations which might be explained by a drift of the lambda sub 2,2 gravity phase angle. No conclusive movement of lambda sub 2,2 was detected. But a measured upper bound on the drift of less than 0.05 degrees/year is still compatible with possible slow moving irregularities in the region of the core-mantle boundary.
Measurement of the Lambda b lifetime in the exclusive decay Lambda b --> J/psi Lambda.
Abazov, V M; Abbott, B; Abolins, M; Acharya, B S; Adams, M; Adams, T; Aguilo, E; Ahn, S H; Ahsan, M; Alexeev, G D; Alkhazov, G; Alton, A; Alverson, G; Alves, G A; Anastasoaie, M; Ancu, L S; Andeen, T; Anderson, S; Andrieu, B; Anzelc, M S; Arnoud, Y; Arov, M; Arthaud, M; Askew, A; Asman, B; Jesus, A C S Assis; Atramentov, O; Autermann, C; Avila, C; Ay, C; Badaud, F; Baden, A; Bagby, L; Baldin, B; Bandurin, D V; Banerjee, P; Banerjee, S; Barberis, E; Barfuss, A-F; Bargassa, P; Baringer, P; Barreto, J; Bartlett, J F; Bassler, U; Bauer, D; Beale, S; Bean, A; Begalli, M; Begel, M; Belanger-Champagne, C; Bellantoni, L; Bellavance, A; Benitez, J A; Beri, S B; Bernardi, G; Bernhard, R; Berntzon, L; Bertram, I; Besançon, M; Beuselinck, R; Bezzubov, V A; Bhat, P C; Bhatnagar, V; Biscarat, C; Blazey, G; Blekman, F; Blessing, S; Bloch, D; Bloom, K; Boehnlein, A; Boline, D; Bolton, T A; Borissov, G; Bos, K; Bose, T; Brandt, A; Brock, R; Brooijmans, G; Bross, A; Brown, D; Buchanan, N J; Buchholz, D; Buehler, M; Buescher, V; Burdin, S; Burke, S; Burnett, T H; Buszello, C P; Butler, J M; Calfayan, P; Calvet, S; Cammin, J; Caron, S; Carvalho, W; Casey, B C K; Cason, N M; Castilla-Valdez, H; Chakrabarti, S; Chakraborty, D; Chan, K; Chan, K M; Chandra, A; Charles, F; Cheu, E; Chevallier, F; Cho, D K; Choi, S; Choudhary, B; Christofek, L; Christoudias, T; Cihangir, S; Claes, D; Clément, B; Clément, C; Coadou, Y; Cooke, M; Cooper, W E; Corcoran, M; Couderc, F; Cousinou, M-C; Crépé-Renaudin, S; Cutts, D; Cwiok, M; da Motta, H; Das, A; Davies, G; De, K; de Jong, P; de Jong, S J; De La Cruz-Burelo, E; De Oliveira Martins, C; Degenhardt, J D; Déliot, F; Demarteau, M; Demina, R; Denisov, D; Denisov, S P; Desai, S; Diehl, H T; Diesburg, M; Dominguez, A; Dong, H; Dudko, L V; Duflot, L; Dugad, S R; Duggan, D; Duperrin, A; Dyer, J; Dyshkant, A; Eads, M; Edmunds, D; Ellison, J; Elvira, V D; Enari, Y; Eno, S; Ermolov, P; Evans, H; Evdokimov, A; Evdokimov, V N; Ferapontov, A V; Ferbel, T; Fiedler, F; Filthaut, F; Fisher, W; Fisk, H E; Ford, M; Fortner, M; Fox, H; Fu, S; Fuess, S; Gadfort, T; Galea, C F; Gallas, E; Galyaev, E; Garcia, C; Garcia-Bellido, A; Gavrilov, V; Gay, P; Geist, W; Gelé, D; Gerber, C E; Gershtein, Y; Gillberg, D; Ginther, G; Gollub, N; Gómez, B; Goussiou, A; Grannis, P D; Greenlee, H; Greenwood, Z D; Gregores, E M; Grenier, G; Gris, Ph; Grivaz, J-F; Grohsjean, A; Grünendahl, S; Grünewald, M W; Guo, F; Guo, J; Gutierrez, G; Gutierrez, P; Haas, A; Hadley, N J; Haefner, P; Hagopian, S; Haley, J; Hall, I; Hall, R E; Han, L; Hanagaki, K; Hansson, P; Harder, K; Harel, A; Harrington, R; Hauptman, J M; Hauser, R; Hays, J; Hebbeker, T; Hedin, D; Hegeman, J G; Heinmiller, J M; Heinson, A P; Heintz, U; Hensel, C; Herner, K; Hesketh, G; Hildreth, M D; Hirosky, R; Hobbs, J D; Hoeneisen, B; Hoeth, H; Hohlfeld, M; Hong, S J; Hooper, R; Hossain, S; Houben, P; Hu, Y; Hubacek, Z; Hynek, V; Iashvili, I; Illingworth, R; Ito, A S; Jabeen, S; Jaffré, M; Jain, S; Jakobs, K; Jarvis, C; Jesik, R; Johns, K; Johnson, C; Johnson, M; Jonckheere, A; Jonsson, P; Juste, A; Käfer, D; Kahn, S; Kajfasz, E; Kalinin, A M; Kalk, J M; Kalk, J R; Kappler, S; Karmanov, D; Kasper, J; Kasper, P; Katsanos, I; Kau, D; Kaur, R; Kaushik, V; Kehoe, R; Kermiche, S; Khalatyan, N; Khanov, A; Kharchilava, A; Kharzheev, Y M; Khatidze, D; Kim, H; Kim, T J; Kirby, M H; Kirsch, M; Klima, B; Kohli, J M; Konrath, J-P; Kopal, M; Korablev, V M; Kothari, B; Kozelov, A V; Krop, D; Kryemadhi, A; Kuhl, T; Kumar, A; Kunori, S; Kupco, A; Kurca, T; Kvita, J; Lam, D; Lammers, S; Landsberg, G; Lazoflores, J; Lebrun, P; Lee, W M; Leflat, A; Lehner, F; Lellouch, J; Lesne, V; Leveque, J; Lewis, P; Li, J; Li, L; Li, Q Z; Lietti, S M; Lima, J G R; Lincoln, D; Linnemann, J; Lipaev, V V; Lipton, R; Liu, Y; Liu, Z; Lobo, L; Lobodenko, A; Lokajicek, M; Lounis, A; Love, P; Lubatti, H J; Lyon, A L; Maciel, A K A; Mackin, D; Madaras, R J; Mättig, P; Magass, C; Magerkurth, A; Makovec, N; Mal, P K; Malbouisson, H B; Malik, S; Malyshev, V L; Mao, H S; Maravin, Y; Martin, B; McCarthy, R; Melnitchouk, A; Mendes, A; Mendoza, L; Mercadante, P G; Merkin, M; Merritt, K W; Meyer, A; Meyer, J; Michaut, M; Millet, T; Mitrevski, J; Molina, J; Mommsen, R K; Mondal, N K; Moore, R W; Moulik, T; Muanza, G S; Mulders, M; Mulhearn, M; Mundal, O; Mundim, L; Nagy, E; Naimuddin, M; Narain, M; Naumann, N A; Neal, H A; Negret, J P; Neustroev, P; Nilsen, H; Noeding, C; Nomerotski, A; Novaes, S F; Nunnemann, T; O'dell, V; O'neil, D C; Obrant, G; Ochando, C; Onoprienko, D; Oshima, N; Osta, J; Otec, R; Otero Y Garzón, G J; Owen, M; Padley, P; Pangilinan, M; Panikashvili, N; Parashar, N; Park, S-J; Park, S K; Parsons, J; Partridge, R; Parua, N; Patwa, A; Pawloski, G; Perea, P M; Peters, K; Peters, Y; Pétroff, P; Petteni, M; Piegaia, R; Piper, J; Pleier, M-A; Podesta-Lerma, P L M; Podstavkov, V M; Pogorelov, Y; Pol, M-E; Pompos, A; Pope, B G; Popov, A V; Potter, C; Prado da Silva, W L; Prosper, H B; Protopopescu, S; Qian, J; Quadt, A; Quinn, B; Rakitine, A; Rangel, M S; Rani, K J; Ranjan, K; Ratoff, P N; Renkel, P; Reucroft, S; Rich, P; Rijssenbeek, M; Ripp-Baudot, I; Rizatdinova, F; Robinson, S; Rodrigues, R F; Royon, C; Rubinov, P; Ruchti, R; Safronov, G; Sajot, G; Sánchez-Hernández, A; Sanders, M P; Santoro, A; Savage, G; Sawyer, L; Scanlon, T; Schaile, D; Schamberger, R D; Scheglov, Y; Schellman, H; Schieferdecker, P; Schliephake, T; Schmitt, C; Schwanenberger, C; Schwartzman, A; Schwienhorst, R; Sekaric, J; Sengupta, S; Severini, H; Shabalina, E; Shamim, M; Shary, V; Shchukin, A A; Shivpuri, R K; Shpakov, D; Siccardi, V; Simak, V; Sirotenko, V; Skubic, P; Slattery, P; Smirnov, D; Smith, R P; Snow, G R; Snow, J; Snyder, S; Söldner-Rembold, S; Sonnenschein, L; Sopczak, A; Sosebee, M; Soustruznik, K; Souza, M; Spurlock, B; Stark, J; Steele, J; Stolin, V; Stone, A; Stoyanova, D A; Strandberg, J; Strandberg, S; Strang, M A; Strauss, M; Ströhmer, R; Strom, D; Strovink, M; Stutte, L; Sumowidagdo, S; Svoisky, P; Sznajder, A; Talby, M; Tamburello, P; Tanasijczuk, A; Taylor, W; Telford, P; Temple, J; Tiller, B; Tissandier, F; Titov, M; Tokmenin, V V; Tomoto, M; Toole, T; Torchiani, I; Trefzger, T; Tsybychev, D; Tuchming, B; Tully, C; Tuts, P M; Unalan, R; Uvarov, L; Uvarov, S; Uzunyan, S; Vachon, B; van den Berg, P J; van Eijk, B; Van Kooten, R; van Leeuwen, W M; Varelas, N; Varnes, E W; Vartapetian, A; Vasilyev, I A; Vaupel, M; Verdier, P; Vertogradov, L S; Verzocchi, M; Villeneuve-Seguier, F; Vint, P; Von Toerne, E; Voutilainen, M; Vreeswijk, M; Wagner, R; Wahl, H D; Wang, L; Wang, M H L S; Warchol, J; Watts, G; Wayne, M; Weber, G; Weber, M; Weerts, H; Wenger, A; Wermes, N; Wetstein, M; White, A; Wicke, D; Wilson, G W; Wimpenny, S J; Wobisch, M; Wood, D R; Wyatt, T R; Xie, Y; Yacoob, S; Yamada, R; Yan, M; Yasuda, T; Yatsunenko, Y A; Yip, K; Yoo, H D; Youn, S W; Yu, C; Yu, J; Yurkewicz, A; Zatserklyaniy, A; Zeitnitz, C; Zhang, D; Zhao, T; Zhou, B; Zhu, J; Zielinski, M; Zieminska, D; Zieminski, A; Zivkovic, L; Zutshi, V; Zverev, E G
2007-10-01
We have measured the Lambda b lifetime using the exclusive decay Lambda b --> J/psi Lambda, based on 1.2 fb(-1) of data collected with the D0 detector during 2002-2006. From 171 reconstructed Lambda b decays, where the J/psi and Lambda are identified via the decays J/psi --> mu+ mu- and Lambda --> ppi, we measured the Lambda b lifetime to be tau(Lambda b)=1.218 (+0.130)/(-0.115) (stat) +/- 0.042(syst) ps. We also measured the B0 lifetime in the decay B0 --> J/psi(mu+ mu-)K(0)/(S)(pi+ pi-) to be tau(B0)=1.501 (+0.078)/(-0.074) (stat) +/- 0.050(syst) ps, yielding a lifetime ratio of tau(Lambda b)/tau(B0)=0.811 (+0.096)/(-0.087) (stat) +/- 0.034(syst). PMID:17930660
ERIC Educational Resources Information Center
Futhey, Tracy
2005-01-01
In this column, the author discusses the four key questions related to the National LambdaRail (NLR) networking technology. NLR uses Dense Wave Division Multiplexing (DWDM) to enable multiple networks to coexist on a national fiber footprint, and is owned and operated not by carriers, but by the research and education community. The NLR Board…
Existence of {sub {lambda}}{sub {lambda}}{sup 4}H: A variational Monte Carlo search
Shoeb, Mohammad
2005-02-01
A variational Monte Carlo (VMC) calculation for the binding energy B{sub {lambda}}{sub {lambda}} of the lightest hypernucleus {sub {lambda}}{sub {lambda}}{sup 4}H has been performed in the four-body {lambda}{lambda}pn model. A range of input {lambda}{lambda} potentials of moderate strength produce a particle-stable {sub {lambda}}{sub {lambda}}{sup 4}H for the simulated NSC97e and f {lambda}N potentials, whereas the phenomenological Minnesota {lambda}N potential needs a much stronger {lambda}{lambda} potential to bind. The VMC results for B{sub {lambda}}{sub {lambda}} agree with the prediction of the stochastic variational model but contradict the recent Faddeev-Yakubovsky calculation. As reported earlier, B{sub {lambda}}{sub {lambda}} is sensitive to the triplet {lambda}N channel for a given {lambda}{lambda} potential. The B{sub {lambda}}{sub {lambda}} of {sub {lambda}}{sub {lambda}}{sup 4}H in the three-body {lambda}{lambda}d cluster model is consistent with but slightly lower than the Faddeev calculation. The VMC method predicts a stable {sub {lambda}}{sub {lambda}}{sup 4}H system in both models and thus offers the possibility of identifying {sub {lambda}}{sub {lambda}}{sup 4}H in a future extension of E906 or of a related experiment at KEK, provided the simulated potentials are true representations of realistic Nijmegen potentials.
Observation of B+ --> Lambda c+ Lambda c- K+ and B0 --> Lambda c+ Lambda c- K0 decays.
Gabyshev, N; Abe, K; Abe, K; Adachi, I; Aihara, H; Asano, Y; Aulchenko, V; Aushev, T; Bahinipati, S; Bakich, A M; Balagura, V; Barberio, E; Bartel, W; Bay, A; Bedny, I; Bitenc, U; Bizjak, I; Bondar, A; Bozek, A; Bracko, M; Browder, T E; Chen, A; Chen, W T; Cheon, B G; Chistov, R; Choi, Y; Chuvikov, A; Cole, S; Dalseno, J; Danilov, M; Dash, M; Drutskoy, A; Eidelman, S; Garmash, A; Gershon, T; Gokhroo, G; Golob, B; Haba, J; Hayasaka, K; Hayashii, H; Hazumi, M; Hokuue, T; Hoshi, Y; Hou, S; Hou, W-S; Hsiung, Y B; Ikado, K; Imoto, A; Inami, K; Itoh, R; Iwasaki, M; Iwasaki, Y; Kang, J H; Kawasaki, T; Khan, H R; Kichimi, H; Kim, S M; Korpar, S; Krokovny, P; Kulasiri, R; Kuo, C C; Kuzmin, A; Kwon, Y-J; Leder, G; Lesiak, T; Lin, S-W; Liventsev, D; Majumder, G; Matsumoto, T; Mitaroff, W; Miyabayashi, K; Miyata, H; Miyazaki, Y; Mizuk, R; Nakano, E; Nakao, M; Natkaniec, Z; Nishida, S; Ogawa, S; Ohshima, T; Okabe, T; Okuno, S; Olsen, S L; Ozaki, H; Palka, H; Park, C W; Park, K S; Pestotnik, R; Piilonen, L E; Sakai, Y; Sato, N; Satoyama, N; Schietinger, T; Schneider, O; Schwanda, C; Seidl, R; Senyo, K; Sevior, M E; Shapkin, M; Shibuya, H; Somov, A; Soni, N; Stamen, R; Stanic, S; Staric, M; Sumiyoshi, T; Tamai, K; Tamura, N; Tanaka, M; Taylor, G N; Teramoto, Y; Tian, X C; Tsukamoto, T; Uehara, S; Uglov, T; Ueno, K; Uno, S; Urquijo, P; Varner, G; Varvell, K E; Villa, S; Wang, C C; Wang, C H; Watanabe, Y; Won, E; Xie, Q L; Yamaguchi, A; Yamauchi, M; Ying, J; Zhang, Z P
2006-11-17
We report the first measurements of the doubly charmed baryonic B decays B --> Lambda c+ Lambda c- K. The B+ --> Lambda c+ Lambda c- K+ decay is observed with a branching fraction of (6.5(-0.9)(+1.0)+/-1.1+/-3.4)x10(-4) and a statistical significance of 15.4sigma. The B0 --> Lambda c+ Lambda c- K0 decay is observed with a branching fraction of (7.9(-2.3)(+2.9)+/-1.2+/-4.1)x10(-4) and a statistical significance of 6.6sigma. The branching fraction errors are statistical, systematic, and the error resulting from the uncertainty of the Lambda c+ --> pK- pi+ decay branching fraction. The analysis is based on 357 fb(-1) of data accumulated at the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+ e- collider. PMID:17155677
NASA Astrophysics Data System (ADS)
Shimomura, Yasuo
The ITER Project has been significantly developed in the past years in preparation for its construction. The ITER Negotiators have developed a draft Joint Implementation Agreement (JIA), ready for completion following the nomination of the Project’s Director General (DG). The ITER International Team and Participant Teams have continued technical and organizational preparations. The actual construction will be able to start immediately after the international ITER organization will be established, following signature of the JIA. The Project is now strongly supported by all the participants as well as by the scientific community with the final high-level negotiations, focused on siting and the concluding details of cost sharing, started in December 2003. The EU, with Cadarache, and Japan, with Rokkasho, have both promised large contributions to the project to strongly support their construction site proposals. The extent to which they both wish to host the ITER facility is such that large contributions to a broader collaboration among the Parties are also proposed by them. This covers complementary activities to help accelerate fusion development towards a viable power source, as well as may allow the Participants to reach a conclusion on ITER siting.
{Lambda} single-particle energies
Bodmer, A.R.; Usmani, Q.N.; Sami, M.
1995-08-01
We are continuing our work on the {Lambda} hyperon single-particle (s.p.) energies and their interpretation in terms of the basic {Lambda}-nuclear interactions. In particular we are interpreting the results obtained by S.C. Pieper, A. Usmani and Q.N. Usmani. We obtain about 30 MeV for the repulsive contribution of the three-body {Lambda}NN forces in nuclear matter. We are able to exclude purely {open_quotes}dispersive{close_quotes} {Lambda}NN forces. We are investigating the mix of dispersive and two-pion-exchange {Lambda}NN forces which provide a fit to the s.p. data. For interactions, which provide a fit to the s.p. data, the {Lambda} binding energy as a function of the nuclear matter density shows characteristic saturation features with a maximum at a density not very different from that of normal nuclear matter. We obtain a more precise measure of the space-exchange part of the {Lambda}-nuclear force than was previously available, corresponding to an exchange parameter {approx_equal} 0.32. The space-exchange force is rather directly related to the effective mass of a {Lambda} in the nuclear medium and turns out to be about 70% of its free mass. As a result, we also obtain a much better value for the p-state {Lambda}-nucleus potential which is about 40% of the s-state potential. The A binding to nuclear matter is determined to be {approx_equal} 28 MeV.
Solution of the symmetric eigenproblem AX=lambda BX by delayed division
NASA Technical Reports Server (NTRS)
Thurston, G. A.; Bains, N. J. C.
1986-01-01
Delayed division is an iterative method for solving the linear eigenvalue problem AX = lambda BX for a limited number of small eigenvalues and their corresponding eigenvectors. The distinctive feature of the method is the reduction of the problem to an approximate triangular form by systematically dropping quadratic terms in the eigenvalue lambda. The report describes the pivoting strategy in the reduction and the method for preserving symmetry in submatrices at each reduction step. Along with the approximate triangular reduction, the report extends some techniques used in the method of inverse subspace iteration. Examples are included for problems of varying complexity.
Radiative decays of the Sigma0(1385) and Lambda(1520) hyperons
Simon Taylor; Gordon Mutchler; CLAS Collaboration
2005-03-01
The electromagnetic decays of the {Sigma}{sup 0}(1385) and {Lambda}(1520) hyperons were studied in photon-induced reactions {gamma} p {yields} K{sup +} {Lambda}(1116){gamma} in the CLAS detector at the Thomas Jefferson National Accelerator Facility. We report the first observation of the radiative decay of the {Sigma}{sup 0}(1385) and a measurement of the {Lambda}(1520) radiative decay width. For the {Sigma}{sup 0}(1385) {yields} {Lambda}(1116){gamma} transition, we measured a partial width of 479 {+-} 120(stat){sub -100}{sup +81}(sys) keV, larger than all of the existing model predictions. For the {Lambda}(1520) {yields} {Lambda}(1116){gamma} transition, we obtained a partial width of 167 {+-} 43(stat){sub -12}{sup +26}(sys) keV.
Novel bacteriophage lambda mutation affecting lambda head assembly.
Georgopoulos, C P; Bisig, R; Magazin, M; Eisen, H; Court, D
1979-01-01
A novel phage lambda mutation, called dc10, which interferes with proper lambda head assembly has been isolated and characterized. Phage lambda carrying this mutation is (i) unable to form plaques at 30 or 37 degrees C but does so at 42 degrees C and (ii) unable to form plaques at 42 degrees C on pN-constitutive hosts. Both properties are due to dc10 since all phage revertants for one phenotype simultaneously lose the other phenotype and vice versa. The dc10 mutation has been mapped in the B gene and has been shown to be dominant over the corresponding wild-type product. At 30 degrees C the dc10 mutation results in the formation of abnormal petit lambda heads made up of pE, pB, pC, and pNu3. Under pN-constitutive conditions, the dc10 mutation results in the formation of abnormal petit lambda heads made of pE, X1, and X2 only. A model to explain the data is presented. Images PMID:430610
Spectroscopic Research of Lambda Hypdernuclei at JLab Hall C
Gogami, Toshiyuki; et. al.,
2014-03-01
A Lambda hyperon which has a strangeness can be bound in deep inside of a nucleus since a Λ does not suffer from the Pauli exclusion principle from nucleons. Thus, a Λ could be a useful tool to investigate inside of a nucleus. Since 2000, Lambda hypernuclear spectroscopic experiments by the (e,e'k) reaction have been performed at the experimental hall C in Thomas Jefferson National Accelerator Facility (JLab Hall C). An experiment, JLab E05-115 was carried out to investigate Lambda hypernuclei with a wide mass range (the mass number, A = 7, 9, 10, 12, 52). The latest analysis status of JLab E05-115 experiment is discussed in the present article.
A new three-baryon-force in {lambda}{lambda} hypernuclei
Nemura, Hidekatsu
2008-04-29
We describe a few-body calculation of {sub {lambda}}{sub {lambda}}{sup 5}H as well as {sub {lambda}}{sub {lambda}}{sup 4}H and {sub {lambda}}{sub {lambda}}{sup 6}He taking account fully coupled-channel two-baryon potentials acting among the octet of baryons. The wave function includes not only pnn{lambda}{lambda} and ppnn{xi}{sup -} components but also pnn{lambda}{sigma}{sup 0}, ppn{lambda}{sigma}{sup -}, pnn{sigma}{sup 0}{sigma}{sup 0} and ppn{sigma}{sup 0}{sigma}{sup -}. An effective YY potential based on Nijmegen model D is used. We find that the pnn{lambda}{sigma}{sup 0} and ppn{lambda}{sigma}{sup -} components play an important role in producing the {sub {lambda}}{sub {lambda}}{sup 5}H bound state. The present result requires the introduction of a new coupled-channel three-body-force, N{lambda}{lambda}--NN{xi}, if the intermediate pnn{lambda}{sigma}{sup 0} and ppn{lambda}{sigma}{sup -} states are eliminated from the model space.
New concurrent iterative methods with monotonic convergence
Yao, Qingchuan
1996-12-31
This paper proposes the new concurrent iterative methods without using any derivatives for finding all zeros of polynomials simultaneously. The new methods are of monotonic convergence for both simple and multiple real-zeros of polynomials and are quadratically convergent. The corresponding accelerated concurrent iterative methods are obtained too. The new methods are good candidates for the application in solving symmetric eigenproblems.
Sapozhnikov, M. G.
2007-06-13
The longitudinal polarization of {lambda} and {lambda}-bar hyperons produced in deep-inelastic scattering of 160 GeV/c polarized positive muons is studied in the COMPASS (CERN NA58) experiment. Preliminary results on the longitudinal polarization of {lambda} and {lambda}-bar from data collected during the 2003 run are presented.
Telluric lines in the region lambda lambda 6327.5-6330.0 angstrom angstrom
NASA Technical Reports Server (NTRS)
Alikayeva, K. V.
1973-01-01
The solar spectrum region lambda lambda 6327.5 to 6330.0 AA was investigated. Six new telluric lines were found. The behavior of two of them (lambda 6328.51 and lambda 6328.71 A) is the same as identified molecular oxygen lines in the region. The lines lambda 6328.27, 6329.12, and 6329.29 A are more intensive when there are days with high humidity.
Photoproduction of the Lambda*(1520) Hyperon
Z. W. Zhao, H. Y. Lu, L. Graham, K. Park, R. W. Gothe
2010-08-01
The photoproduction of the Lambda*(1520) on both the proton and neutron have been studied by using the CLAS eg3 run data set. The reactions are gammad-->K+Lambda*(n) and gammad-->K0Lambda*(p) with Lambda*-->pK-. Preliminary total and differential cross sections have been extracted in the photon energy region 1.75 GeV
The ITER project construction status
NASA Astrophysics Data System (ADS)
Motojima, O.
2015-10-01
The pace of the ITER project in St Paul-lez-Durance, France is accelerating rapidly into its peak construction phase. With the completion of the B2 slab in August 2014, which will support about 400 000 metric tons of the tokamak complex structures and components, the construction is advancing on a daily basis. Magnet, vacuum vessel, cryostat, thermal shield, first wall and divertor structures are under construction or in prototype phase in the ITER member states of China, Europe, India, Japan, Korea, Russia, and the United States. Each of these member states has its own domestic agency (DA) to manage their procurements of components for ITER. Plant systems engineering is being transformed to fully integrate the tokamak and its auxiliary systems in preparation for the assembly and operations phase. CODAC, diagnostics, and the three main heating and current drive systems are also progressing, including the construction of the neutral beam test facility building in Padua, Italy. The conceptual design of the Chinese test blanket module system for ITER has been completed and those of the EU are well under way. Significant progress has been made addressing several outstanding physics issues including disruption load characterization, prediction, avoidance, and mitigation, first wall and divertor shaping, edge pedestal and SOL plasma stability, fuelling and plasma behaviour during confinement transients and W impurity transport. Further development of the ITER Research Plan has included a definition of the required plant configuration for 1st plasma and subsequent phases of ITER operation as well as the major plasma commissioning activities and the needs of the accompanying R&D program to ITER construction by the ITER parties.
Wu, C-H; Wang, M-Z; Abe, K; Adachi, I; Aihara, H; Aulchenko, V; Aushev, T; Bahinipati, S; Bakich, A M; Balagura, V; Bay, A; Belous, K; Bitenc, U; Bizjak, I; Blyth, S; Bondar, A; Bozek, A; Browder, T E; Chao, Y; Chen, A; Chen, W T; Cheon, B G; Choi, Y; Choi, Y K; Chuvikov, A; Cole, S; Dalseno, J; Danilov, M; Dash, M; Eidelman, S; Gabyshev, N; Gershon, T; Go, A; Gokhroo, G; Gorisek, A; Ha, H; Haba, J; Hayasaka, K; Hayashii, H; Hazumi, M; Heffernan, D; Hokuue, T; Hou, S; Hou, W-S; Hsiung, Y B; Iijima, T; Inami, K; Ishikawa, A; Itoh, R; Iwasaki, M; Iwasaki, Y; Kang, J H; Kataoka, S U; Katayama, N; Kawai, H; Kawasaki, T; Khan, H R; Kichimi, H; Kim, H J; Kim, H O; Kim, Y J; Krizan, P; Krokovny, P; Kulasiri, R; Kumar, R; Kuo, C C; Kuzmin, A; Kwon, Y-J; Leder, G; Lee, J; Lee, Y-J; Lesiak, T; Lin, S-W; Liventsev, D; Majumder, G; Mandl, F; Matsumoto, T; Matyja, A; McOnie, S; Mitaroff, W; Miyabayashi, K; Miyake, H; Miyata, H; Miyazaki, Y; Mizuk, R; Mori, T; Nakano, E; Nakao, M; Natkaniec, Z; Nishida, S; Nitoh, O; Ogawa, S; Ohshima, T; Okabe, T; Okuno, S; Olsen, S L; Onuki, Y; Ozaki, H; Pakhlov, P; Palka, H; Park, H; Park, K S; Pestotnik, R; Piilonen, L E; Sakai, Y; Schietinger, T; Schneider, O; Schwartz, A J; Seidl, R; Sevior, M E; Shapkin, M; Shibuya, H; Sidorov, V; Sokolov, A; Somov, A; Soni, N; Stanic, S; Staric, M; Stoeck, H; Sumiyoshi, T; Takasaki, F; Tanaka, M; Taylor, G N; Teramoto, Y; Tian, X C; Tsuboyama, T; Tsukamoto, T; Uehara, S; Uglov, T; Ueno, K; Uno, S; Urquijo, P; Usov, Y; Varner, G; Wang, C C; Wang, C H; Watanabe, Y; Won, E; Yabsley, B D; Yamaguchi, A; Yamashita, Y; Zhang, L M; Zhang, Z P
2006-10-20
We study the baryonic charmonium decays of B mesons B+-->etacK+ and B+-->J/psiK+, where the etac and J/psi subsequently decay into a pp[over] or LambdaLambda[over] pair. We measure the J/psi-->pp[over] and LambdaLambda[over] anisotropy parameters alphaB=-0.60+/-0.13+/-0.14 (pp[over]), -0.44+/-0.51+/-0.31 (LambdaLambda[over ]) and compare to results from e;{+}e;{-}-->J/psi formation experiments. We also report the first observation of etac-->LambdaLambda[over]. The measured branching fraction is B(etac-->LambdaLambda[over ])=(0.87(+0.24)/(-0.21)(stat)(+0.09/-0.14) (syst)+/-0.27(PDG))x10-3. This study is based on a 357 fb-1 data sample recorded on the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+ e- collider. PMID:17155387
Measurement of the Lambda(b) lifetime in the exclusive decay Lambda(b) ---> J / psi Lambda
Abazov, V.M.; Abbott, B.; Abolins, M.; Acharya, B.S.; Adams, M.; Adams, T.; Aguilo, E.; Ahn, S.H.; Ahsan, M.; Alexeev, G.D.; Alkhazov, G.; /Buenos Aires U. /Rio de Janeiro, CBPF /Rio de Janeiro State U. /Sao Paulo, IFT /Alberta U. /Simon Fraser U. /York U., Canada /McGill U. /Hefei, CUST /Andes U., Bogota /Charles U.
2007-04-01
We have measured the {lambda}{sub b} lifetime using the exclusive decay {lambda}{sub b}{yields}J/{psi}{lambda}, based on 1.2 fb{sup -1} of data collected with the D0 detector during 2002-2006. From 171 reconstructed {lambda}{sub b} decays, where the J/{psi} and {lambda} are identified via the decays J/{psi}{yields}{mu}{sup +}{mu}{sup -} and {lambda}{yields}p{pi}, we measured the {lambda}{sub b} lifetime to be {tau}({lambda}{sub b})=1.218{sub -0.115}{sup +0.130}(stat){+-}0.042(syst) ps. We also measured the B{sup 0} lifetime in the decay B{sup 0}{yields}J/{psi}({mu}{sup +}{mu}{sup -})K{sub S}{sup 0}({pi}{sup +}{pi}{sup -}) to be {tau}(B{sup 0})=1.501{sub -0.074}{sup +0.078}(stat){+-}0.050(syst) ps, yielding a lifetime ratio of {tau}({lambda}{sub b})/{tau}(B{sup 0})=0.811{sub -0.087}{sup +0.096}(stat){+-}0.034(syst = )
Serologically defined V region subgroups of human lambda light chains.
Solomon, A; Weiss, D T
1987-08-01
The availability of numerous antisera prepared against lambda-type Bence Jones proteins and lambda chains of known amino acid sequence has led to the differentiation and classification of human lambda light chains into one of five V lambda subgroups. The five serologically defined subgroups, V lambda I, V lambda II, V lambda III, V lambda IV, and V lambda VI, correspond to the chemical classification that is based on sequence homologies in the first framework region (FR1). Proteins designated by sequence as lambda V react with specific anti-lambda II antisera and are thus included in the V lambda II subgroup classification. The isotypic nature of the five V lambda subgroups was evidenced through analyses of lambda-type light chains that were isolated from the IgG of normal individuals. Based on analyses of 116 Bence Jones proteins, the frequency of distribution of the lambda I, lambda II/V, lambda III, lambda IV, and lambda VI proteins in the normal lambda chain population is estimated to be 27%, 37%, 23%, 3%, and 10%, respectively. This distribution of V lambda subgroups was comparable to that found among 82 monoclonal Ig lambda proteins. Considerable V lambda intragroup antigenic heterogeneity was also apparent. At least two sub-subgroups were identified among each of the five major V lambda subgroups, implying the existence of multiple genes in the human V lambda genome. The V lambda classification of 54 Ig lambda proteins obtained from patients with primary or multiple myeloma-associated amyloidosis substantiated the preferential association of lambda VI light chains with amyloidosis AL and the predominance of the normally rare V lambda VI subgroup in this disease. PMID:3110284
Measurement of the Lambda 0(b) -> Lambda +(c) pi- branching ratio
Le, Yi; /Johns Hopkins U.
2003-01-01
The authors present a measurement of the {Lambda}{sub b}{sup 0} {yields} {Lambda}{sub c}{sup +} {pi}{sup -} branching ratio in p{bar p} collisions at {radical}s = 1.96 TeV using 65 pb{sup -1} data collected by the Collider Detector at Fermilab (CDF). The measurement starts from reconstructing two decay modes: {Lambda}{sub b}{sup 0} {yields} {Lambda}{sub c}{sup +}{pi}{sup -}, where {Lambda}{sub c}{sup +} {yields} p K{sup -} {pi}{sup +}; and {bar B}{sup 0} {yields} D{sup +}{pi}{sup -}, where D{sup +} {yields} {pi}{sup +} K{sup -} {pi}{sup +}. The authors obtained 96 {+-} 13 {Lambda}{sub b}{sup 0} and 321 {+-} 22 {bar B}{sup 0} candidates from the CDF Run II Two-Track Hadronic Trigger data sample. The relative branching ratio of the two decays is then measured based on the equation: f{sub {Lambda}{sub b}} BR({Lambda}{sub b} {yields} {Lambda}{sub c}{sup +} {pi}{sup -})/f{sub d} BR({bar B}{sup 0} {yields} D{sup +} {pi}{sup -}) = BR(D{sup +} {yields} K{pi}{pi}) N{sub {Lambda}{sub b}} {epsilon}{sub B{sup 0}}/BR({Lambda}{sub c}{sup +} {yields} pK{pi}) N{sub {bar B}{sup 0}} {epsilon}{sub {Lambda}{sub b}}. The measurement gives f{sub {Lambda}{sub b}} BR({Lambda}{sub b} {yields} {Lambda}{sub c}{sup +}{pi}{sup -})/f{sub d} BR({bar B}{sup 0} {yields} D{sup +}{pi}{sup -}) = 0.66 {+-} 0.11(stat) {+-} 0.09(syst) {+-} 0.18(BR). The {Lambda}{sub b}{sup 0} {yields} {Lambda}{sub c}{sup +}{pi}{sup -} branching ratio is then extracted, giving BR({Lambda}{sub b}{sup 0} {yields} {Lambda}{sub c}{sup +}{pi}{sup -}) = (6.6 {+-} 1.2(stat.) {+-} 0.9(syst.) {+-} 2.3(BR+FR)) x 10{sup -3}. The {Lambda}{sub b}{sup 0} sample they reconstructed in this analysis is the largest fully reconstructed {Lambda}{sub b}{sup 0} sample in existence. The result they report here on the {Lambda}{sub b}{sup 0} {yields} {Lambda}{sub c}{sup +}{pi}{sup -} branching ratio is the world's first such measurement.
Bacteriophage lambda-based expression vectors.
Christensen, A C
2001-03-01
Bacteriophage lambda has been in use as a cloning vector for over 25 years, and has been used extensively as an expression vector. The efficiency of packaging and infection, and the simplicity of plaque screening are advantages of lambda as a cloning vector. A number of ingenious modifications help overcome the disadvantages associated with its mode of growth and its size. Some lambda vectors have been designed to be readily converted into plasmids or phagemids, and there are a variety of promoters and fusions that can be used to drive expression of foreign genes. Screening lambda libraries with antibodies or ligands is a powerful way of identifying novel genes. PMID:11434310
Study of Lambda+(c) Cabibbo favored decays containing a Lambda baryon in the final state
Link, J.M.; Yager, P.M.; Anjos, J.C.; Bediaga, I.; Castromonte, C.; Machado, A.A.; Magnin, J.; Massafferri, A.; de Miranda, J.M.; Pepe, I.M.; Polycarpo, E.; dos Reis, A.C.; Carrillo, S.; Casimiro, E.; Cuautle, E.; Sanchez-Hernandez, A.; Uribe, C.; Vazquez, F.; Agostino, L.; Cinquini, L.; Cumalat, J.P.; /Colorado U. /Fermilab /Frascati /Guanajuato U. /Illinois U., Urbana /Indiana U. /Korea U. /Kyungpook Natl. U. /INFN, Milan /Milan U. /North Carolina U. /Pavia U. /INFN, Pavia /Rio de Janeiro, Pont. U. Catol. /Puerto Rico U., Mayaguez /South Carolina U. /Tennessee U. /Vanderbilt U. /Wisconsin U., Madison
2005-05-01
Using data from the FOCUS experiment (FNAL-E831), they study the decay of {Lambda}{sub c}{sup +} baryons into final states contain a {Lambda} hyperon. The branching fractions of {Lambda}{sub c}{sup +} into {Lambda}{pi}{sup +}, {Lambda}{pi}{sup +}{pi}{sup +}{pi}{sup -} and {Lambda}{bar K}{sup 0}K{sup +} relative to that into pK{sup -} {pi}{sup +} are measured to be 0.217 {+-} 0.013 {+-} 0.020, 0.508 {+-} 0.024 {+-} 0.024 and 0.142 {+-} 0.018 {+-} 0.022, respectively. New measurements are also reported. Further, an analysis of the subresonant structure for the {Lambda}{sub c}{sup +} {yields} {Lambda}{pi}{sup +}{pi}{sup +}{pi}{sup -} decay mode is presented.
Abazov, Victor Mukhamedovich
2016-02-09
Here, we studymore » $$\\Lambda$$ and $$\\bar{\\Lambda}$$ production asymmetries in $$p \\bar{p} \\rightarrow \\Lambda (\\bar{\\Lambda}) X$$, $$p \\bar{p} \\rightarrow J/\\psi \\Lambda (\\bar{\\Lambda}) X$$, and $$p \\bar{p} \\rightarrow \\mu^\\pm \\Lambda (\\bar{\\Lambda}) X$$ events recorded by the D0 detector at the Fermilab Tevatron collider at $$\\sqrt{s} = 1.96$$ TeV. We find an excess of $$\\Lambda$$'s ($$\\bar{\\Lambda}$$'s) produced in the proton (antiproton) direction. This forward-backward asymmetry is measured as a function of rapidity. We confirm that the $$\\bar{\\Lambda}/\\Lambda$$ production ratio, measured by several experiments with various targets and a wide range of energies, is a universal function of "rapidity loss", i.e., the rapidity difference of the beam proton and the lambda.« less
Electromagnetic Decay of the $\\Sigma^{0}(1385)$ to $\\Lambda\\gamma$
Keller, Dustin; Adhikari, Krishna; Adikaram-Mudiyanselage, Dasuni; Aghasyan, Mher; Amaryan, Moscov; Baghdasaryan, Hovhannes; Ball, J P; Ball, Jacques; Battaglieri, Marco; Batourine, V; Bedlinskiy, Ivan; Bennett, Robert; Biselli, Angela; Branford, Derek; Briscoe, Wilbert; Brooks, William; Burkert, Volker; Careccia, Sharon; Carman, Daniel; Casey, Liam; Cole, Philip; Contalbrigo, Marco; Crede, Volker; D'Angelo, Annalisa; Daniel, AJI; Dashyan, Natalya; De Vita, Raffaella; De Sanctis, Enzo; Deur, Alexandre; Dey, Biplap; Dickson, Richard; Djalali, Chaden; Doughty, David; Dupre, Raphael; Egiyan, Hovanes; El Alaoui, Ahmed; Elfassi, Lamiaa; Eugenio, Paul; Fedotov, Gleb; Fegan, Stuart; Forest, Tony; Gabrielyan, Marianna; Gavalian, Gagik; Gevorgyan, Nerses; Giovanetti, Kevin; Girod, Francois-Xavier; Gohn, Wesley; Golovach, Evgeny; Gothe, Ralf; Graham, Lewis; Guidal, Michel; Guegan, Baptiste; Hafidi, Kawtar; Hakobyan, Hayk; Hanretty, Charles; Holtrop, Maurik; Ilieva, Yordanka; Ireland, David; Isupov, Evgeny; Jawalkar, Sucheta; Jenkins, David; Jo, Hyon-Suk; Joo, Kyungseon; Khandaker, Mahbubul; Khetarpal, Puneet; Kim, Andrey; Kim, Wooyoung; Klein, Andreas; Klein, Franz; Konczykowski, Piotr; Kubarovsky, Valery; Kuleshov, Sergey; Kuznetsov, Viacheslav; Lu, Haiyun; MacGregor, Ian; Markov, Nikolai; McAndrew, Josephine; KcKinnon, Bryan; Meyer, Curtis; Micherdzinska, Anna; Mirazita, Marco; Mokeev, Viktor; Moreno, Brahim; Moriya, Kei; Morrison, Brian; Moutarde, Herve; Munevar Espitia, Edwin; Nadel-Turonski, Pawel; Ni, Andrey; Niccolai, Silvia; Niculescu, Gabriel; Niculescu, Maria-Ioana; Osipenko, Mikhail; Ostrovidov, Alexander; Paremuzyan, Rafayel; Park, Kijun; Park, Sungkyun; Pasyuk, Eugene; Pasyuk, Evgueni; Pereira, Sergio; Pappalardo, Luciano; Pisano, Silvia; Pogorelko, Oleg; Pozdnyakov, Sergey; Price, John; Procureur, Sebastien; Protopopescu, Dan; Raue, Brian; Ripani, Marco; Ritchie, Barry; Rosner, Guenther; Rossi, Patrizia; Sabatie, Franck; Saini, Mukesh; Salgado, Carlos; Schott, Diane; Schumacher, Reinhard; Seder, Erin; Seraydaryan, Heghine; Sharabian, Youri; Smith, Elton; Smith, Gregory; Sober, Daniel; Stepanyan, Stepan; Stoler, Paul; Strakovski, Igor; Strauch, Steffen; Taiuti, Mauro; Tang, Wei; Taylor, Charles; Vernarsky, Brian; Vineyard, Michael; Voutier, Eric; Weinstein, Lawrence; Watts, Daniel; Wood, Michael; Zachariou, Nicholas; Zana, Lorenzo; Zhao, Bo; Zhao, Zhiwen
2011-04-01
The electromagnetic decay $\\Sigma^0(1385) \\to \\Lambda \\gamma$ was studied using the CLAS detector at the Thomas Jefferson National Accelerator Facility. A real photon beam with a maximum energy of 3.8 GeV was incident on a proton target, producing an exclusive final state of $K^+\\Sigma^{*0}$. We report the decay widths ratio $\\Sigma^0(1385) \\to \\Lambda\\gamma$/ $\\Sigma^0(1385) \\to \\Lambda\\pi^0$ = $1.42 \\pm 0.12(\\text{stat})_{-0.07}^{+0.11}(\\text{sys})$%. This ratio is larger than most theoretical predictions by factors ranging from 1.5-3, but is consistent with the only other experimental measurement. From the reported ratio we calculate the partial width and electromagnetic transition magnetic moment for $\\Sigma^0(1385) \\to \\Lambda\\gamma$.
Bacteriophage lambda as a cloning vector.
Chauthaiwale, V M; Therwath, A; Deshpande, V V
1992-12-01
Extensive research has been directed toward the development of multipurpose lambda vectors for cloning ever since the potential of using coliphage lambda as a cloning vector was recognized in the late 1970s. An understanding of the intrinsic molecular organization and of the genetic events which determine lysis or lysogeny in lambda has allowed investigators to modify it to suit the specific requirements of gene manipulations. Unwanted restriction sites have been altered and arranged together into suitable polylinkers. The development of a highly efficient in vitro packaging system has permitted the introduction of chimeric molecules into hosts. Biological containment of recombinants has been achieved by introducing amber mutations into the lambda genome and by using specific amber suppressor hosts. Taking advantage of the limited range of genome size (78 to 105% of the wild-type size) for its efficient packaging, an array of vectors has been devised to accommodate inserts of a wide size range, the limit being 24 kbp in Charon 40. The central dispensable fragment of the lambda genome can be replaced by a fragment of heterologous DNA, leading to the construction of replacement vectors such as Charon and EMBL. Alternatively, small DNA fragments can be inserted without removing the dispensable region of the lambda genome, as in lambda gt10 and lambda gt11 vectors. In addition, the introduction of many other desirable properties, such as NotI and SfiI sites in polylinkers (e.g., lambda gt22), T7 and T3 promoters for the in vitro transcription (e.g., lambda DASH), and the mechanism for in vivo excision of the intact insert (e.g., lambda ZAP), has facilitated both cloning and subsequent analysis. In most cases, the recombinants can be differentiated from the parental phages by their altered phenotype. Libraries constructed in lambda vectors are screened easily with antibody or nucleic acid probes since several thousand clones can be plated on a single petri dish. Besides
Typed Lambda Calculi and Applications
NASA Astrophysics Data System (ADS)
Curien, Pierre-Louis
Finiteness spaces constitute a categorical model of Linear Logic (LL) whose objects can be seen as linearly topologised spaces, (a class of topological vector spaces introduced by Lefschetz in 1942) and morphisms as continuous linear maps. First, we recall definitions of finiteness spaces and describe their basic properties deduced from the general theory of linearly topologised spaces. Then we give an interpretation of LL based on linear algebra. Second, thanks to separation properties, we can introduce an algebraic notion of totality candidate in the framework of linearly topologised spaces: a totality candidate is a closed affine subspace which does not contain 0. We show that finiteness spaces with totality candidates constitute a model of classical LL. Finally, we give a barycentric simply typed lambda-calculus, with booleans ${\\mathcal{B}}$ and a conditional operator, which can be interpreted in this model. We prove completeness at type ${\\mathcal{B}}^n\\to{\\mathcal{B}}$ for every n by an algebraic method.
Double Lambda and Xi hypernuclei
NASA Astrophysics Data System (ADS)
Nakazawa, Kazuma
2014-09-01
Nuclei with double strangeness (S = -2) provide the key information to understand Baryon-Baryon interaction under the SU(3)f symmetry. Therefore we have carried out the experiments at KEK for quarter a century. Recently, the interaction in S = -2 sector is noted to derive the information of the EOS of neutron star. The Lambda-Lambda interaction has been presented to be weak attractive by NAGARA event which showed the production and decay of 6He double-hypernucleus. The event also presented the lower mass limit of H dibaryon. In other five events, we obtained the knowledge about an excitation level of 10Be double-hypernucleus under the consistency with NAGARA event. Moreover, very recently, we have discovered a Xi-14N system which was deeply bound far from the atomic 3D level (0.17 MeV) for a captured Xi hyperon. Since a 8Li nucleus was associated with the decay of one of twin-hypernuclei, the event was uniquely identified as Xi- + 14N ==> 10BeL + 5HeL. The system was selected from 8 million pictures on the test running for development of ``Overall Scanning'' to be used in the coming experiment. This is the first evidence of Xi hypernucleus to be bound and it is impacting for the study of Xi-N interaction. At J-PARC facility, for the further study of hyperon-hyperon interaction, we plan to perform the E07 experiment at J-PARC. In the workshop, we will review the above knowledge obtained by the experiments at KEK-PS, and discuss developed technologies to detected 102 or more double-hypernuclei in the E07 experiment at J-PARC. Nuclei with double strangeness (S = -2) provide the key information to understand Baryon-Baryon interaction under the SU(3)f symmetry. Therefore we have carried out the experiments at KEK for quarter a century. Recently, the interaction in S = -2 sector is noted to derive the information of the EOS of neutron star. The Lambda-Lambda interaction has been presented to be weak attractive by NAGARA event which showed the production and decay of 6He
Recent developments in Lambda networking
NASA Astrophysics Data System (ADS)
de Laat, C.; Grosso, P.
About 6 years ago the first baby-steps were made on opening up dark fiber and DWDM infrastructure for direct use by ISP's after the transformation of the old style Telecom sector into a market driven business. Since then Lambda workshops, community groups like GLIF and a number of experiments have led to many implementations of hybrid national research and education networks and lightpath-based circuit exchanges as pioneered by SURFnet in GigaPort and NetherLight in collaboration with StarLight in Chicago and Canarie in Canada. This article looks back on those developments, describes some current open issues and research developments and proposes a concept of terabit networking.
Bacteriophage Lambda: a Paradigm Revisited ▿
Fogg, Paul C. M.; Allison, Heather E.; Saunders, Jon R.; McCarthy, Alan J.
2010-01-01
Bacteriophage lambda has an archetypal immunity system, which prevents the superinfection of its Escherichia coli lysogens. It is now known that superinfection can occur with toxigenic lambda-like phages at a high frequency, and here we demonstrate that the superinfection of a lambda lysogen can lead to the acquisition of additional lambda genomes, which was confirmed by Southern hybridization and quantitative PCR. As many as eight integration events were observed but at a very low frequency (6.4 × 10−4) and always as multiple insertions at the established primary integration site in E. coli. Sequence analysis of the complete immunity region demonstrated that these multiply infected lysogens were not immunity mutants. In conclusion, although lambda superinfection immunity can be confounded, it is a rare event. PMID:20375161
US ITER / ORNL
2016-07-12
US ITER Project Manager Ned Sauthoff, joined by Wayne Reiersen, Team Leader Magnet Systems, and Jan Berry, Team Leader Tokamak Cooling System, discuss the U.S.'s role in the ITER international collaboration.
Bacteriophage lambda: early pioneer and still relevant
Casjens, Sherwood R.; Hendrix, Roger W.
2015-01-01
Molecular genetic research on bacteriophage lambda carried out during its golden age from the mid 1950's to mid 1980's was critically important in the attainment of our current understanding of the sophisticated and complex mechanisms by which the expression of genes is controlled, of DNA virus assembly and of the molecular nature of lysogeny. The development of molecular cloning techniques, ironically instigated largely by phage lambda researchers, allowed many phage workers to switch their efforts to other biological systems. Nonetheless, since that time the ongoing study of lambda and its relatives have continued to give important new insights. In this review we give some relevant early history and describe recent developments in understanding the molecular biology of lambda's life cycle. PMID:25742714
Variable cosmological term \\varLambda(t)
NASA Astrophysics Data System (ADS)
Socorro, J.; D'oleire, M.; Pimentel, Luis O.
2015-11-01
We present the case of time-varying cosmological term \\varLambda(t). The main idea arises by proposing that as in the cosmological constant case, the scalar potential is identified as V(φ)=2\\varLambda, with \\varLambda a constant, this identification should be kept even when the cosmological term has a temporal dependence, i.e., V(φ(t))=2\\varLambda(t). We use the Lagrangian formalism for a scalar field φ with standard kinetic energy and arbitrary potential V(φ) and apply this model to the Friedmann-Robertson-Walker (FRW) cosmology. Exact solutions of the field equations are obtained by a special ansatz to solve the Einstein-Klein-Gordon equation and a particular potential for the scalar field and barotropic perfect fluid. We present the evolution on this cosmological term with different scenarios.
The protein interaction map of bacteriophage lambda
2011-01-01
Background Bacteriophage lambda is a model phage for most other dsDNA phages and has been studied for over 60 years. Although it is probably the best-characterized phage there are still about 20 poorly understood open reading frames in its 48-kb genome. For a complete understanding we need to know all interactions among its proteins. We have manually curated the lambda literature and compiled a total of 33 interactions that have been found among lambda proteins. We set out to find out how many protein-protein interactions remain to be found in this phage. Results In order to map lambda's interactions, we have cloned 68 out of 73 lambda open reading frames (the "ORFeome") into Gateway vectors and systematically tested all proteins for interactions using exhaustive array-based yeast two-hybrid screens. These screens identified 97 interactions. We found 16 out of 30 previously published interactions (53%). We have also found at least 18 new plausible interactions among functionally related proteins. All previously found and new interactions are combined into structural and network models of phage lambda. Conclusions Phage lambda serves as a benchmark for future studies of protein interactions among phage, viruses in general, or large protein assemblies. We conclude that we could not find all the known interactions because they require chaperones, post-translational modifications, or multiple proteins for their interactions. The lambda protein network connects 12 proteins of unknown function with well characterized proteins, which should shed light on the functional associations of these uncharacterized proteins. PMID:21943085
Calculation of two-dimensional lambda modes
Belchior, A. Jr. ); Moreira, J.M.L. )
1991-01-01
A system for on-line monitoring of power distribution in small reactors (known as MAP) is under development at COPESP-IPEN. Signals of self-powered neutron detectors are input to a program that estimates the power distribution as an expansion of lambda modes. The modal coefficients are obtained from a least-mean-squares technique adequate for real-time analysis. Three-dimensional lambda modes are synthesized out of one- and two-dimensional lambda modes. As a part of this project, a modification of a computer code was carried out in order to obtain the lambda modes. The results of this effort are summarized. The lambda modes are the solutions of the time-independent multigroup neutron diffusion equation, an eigenvalue equation. Normally, the computer codes produce the fundamental mode corresponding to the largest eigenvalue; their respective interpretations are neutron flux distribution and effective multiplication factor. For calculating higher order lambda modes it is usually necessary to eliminate the contribution of the lower modes from the fission source.
CO{sub 2} laser technology for advanced particle accelerators
Pogorelsky, I.V.
1996-06-01
Short-pulse, high-power CO{sub 2} lasers open new prospects for development of ultra-high gradient laser-driven electron accelerators. The advantages of {lambda}=10 {mu}m CO{sub 2} laser radiation over the more widely exploited solid state lasers with {lambda}{approximately}1 {mu}m are based on a {lambda}{sup 2}-proportional ponderomotive potential, {lambda}-proportional phase slippage, and {lambda}-proportional scaling of the laser accelerator structures. We show how a picosecond terawatt CO{sub 2} laser that is under construction at the Brookhaven Accelerator Test Facility may benefit the ATF`s experimental program of testing far-field, near-field, and plasma accelerator schemes.
Aubert, B.
2007-09-14
We study the e+e- --> Lambda anti-Lambda gamma, Lambda anti-Sigma0 gamma, Sigma0 anti-Sigma0 gamma processes using 230 fb-1 of integrated luminosity collected by the BaBar detector at e+e- center-of-mass energy of 10.58 GeV. From the analysis of the baryon-antibaryon mass spectra the cross sections for e+e- --> Lambda anti-Lambda, Lambda anti-Sigma0, Sigma0 anti-Sigma0 are measured in the dibaryon mass range from threshold up to 3 GeV/c{sup 2}. The ratio of electric and magnetic form factors, |G{sub E}/G{sub M}|, is measured for e+e- --> Lambda anti-Lambda, and limits on the relative phase between Lambda form factors are obtained. We also measure the J/psi --> Lambda anti-Lambda, Sigma0 anti-Sigma0 and psi(2S) --> Lambda anti-Lambda branching fractions.
Spectrum of class-M supergiants in the region lambda lambda 7000-6000 angstrom
NASA Technical Reports Server (NTRS)
Orlov, M. Y.; Rodriguez, M. H.; Shavrina, A. V.
1973-01-01
A general description is given of the spectrum of four M-supergiants in the region lambda lambda 7000-6000 A from high-dispersion spectrograms (6 A/mm). The equivalent widths of several hundred lines and depths of some molecular band heads were measured.
The Heavy Mass Expansion lambda(sub)b -> lambda(sub)c Decays
Mannel, Thomas; Roberts, Winston
1992-11-01
We point out that in the decays of the lambda(sub)b to lambda(sub)c one can find predictions which - in the framework of the 1/m(sub)c expansion - do not receive corrections in any order of 1/m(sub)c. We discuss QCD corrections to these predictions and examine some of the consequences for nonleptonic decays.
Hashimoto, O; Honda, D; Kaneta, M; Kato, F; Kawama, D; Maruyama, N; Matsumura, A; Nakamura, S N; Nomura, H; Nonaka, K; Ohtani, A; Okayasu, Y; Osaka, M; Oyamada, M; Sumihama, M; Tamura, H; Baker, O K; Cole, L; Christy, M; Gueye, P; Keppel, C; Tang, L; Yuan, L; Acha, A; Baturin, P; Boeglin, W; Kramer, L; Markowitz, P; Pamela, P; Perez, N; Raue, B; Reinhold, J; Rivera, R; Kato, S; Sato, Y; Takahashi, T; Daniel, A; Hungerford, Ed V; Ispiryan, M; Kalantarians, N; Lan, K J; Li, Y; Miyoshi, T; Randeniya, S; Rodriguez, V M; Bosted, P; Carlini, R; Ent, R; Fenker, H; Gaskell, D; Jones, M; Mack, D; Roche, J; Smith, G; Tvaskis, V; Vulcan, W; Wood, S; Yan, C; Asaturyan, A; Asaturyan, R; Egiyan, K; Mkrtchyan, H; Margaryan, A; Navasardyan, T; Tadevosyan, V; Zamkochian, S; Hu, B; Song, Y; Luo, W; Androic, D; Furic, M; Petkovic, T; Seva, T; Ahmidouch, A; Danagoulian, S; Gasparian, A; Halkyard, R; Johnson, K; Simicevic, N; Wells, S; Niculescu, G; Niculescu, M I; Gan, L; Benmokhtar, F; Horn, T; Elassar, M; Gibson, E F
2011-09-01
The binding energy of 7LambdaHe has been obtained for the first time with reaction spectroscopy using the (e, e'K+) reaction at Jefferson Lab's Hall C. A comparison among the binding energies of the A = 7 T = l iso-triplet hypernuclei, 7LambdaHe, 7LambdaLi*and 7LambdaBe, is made and possible charge symmetry breaking (CSB) in the LambdaN potential is discussed. For 7LambdaHe and 7LambdaBe, the shifts in binding energies are opposite to those predicted by a recent cluster model calculation, which assumes that the unexplained part of the binding energy difference between 4LambdaH and 4LambdaHe, is due to the CSB of the LambdaN potential. Further examination of CSB in light hypernuclear systems is required both experimentally and theoretically.
LambdaSa1 and LambdaSa2 Prophage Lysins of Streptococcus agalactiae▿
Pritchard, David G.; Dong, Shengli; Kirk, Marion C.; Cartee, Robert T.; Baker, John R.
2007-01-01
Putative N-acetylmuramyl-l-alanine amidase genes from LambdaSa1 and LambdaSa2 prophages of Streptococcus agalactiae were cloned and expressed in Escherichia coli. The purified enzymes lysed the cell walls of Streptococcus agalactiae, Streptococcus pneumoniae, and Staphylococcus aureus. The peptidoglycan digestion products in the cell wall lysates were not consistent with amidase activity. Instead, the structure of the muropeptide digestion fragments indicated that both the LambdaSa1 and LambdaSa2 lysins exhibited γ-d-glutaminyl-l-lysine endopeptidase activity. The endopeptidase cleavage specificity of the lysins was confirmed using a synthetic peptide substrate corresponding to a portion of the stem peptide and cross bridge of Streptococcus agalactiae peptidoglycan. The LambdaSa2 lysin also displayed β-d-N-acetylglucosaminidase activity. PMID:17905888
A Spectral Atlas of lambda Bootis Stars
NASA Astrophysics Data System (ADS)
Paunzen, E.; Heiter, U.
2014-06-01
Since the discovery of lambda Bootes stars, a permanent confusion about their classification can be found in literature. This group of non-magnetic, Population I, metal-poor A to F-type stars, has often been used as some sort of trash can for "exotic" and spectroscopically dubious objects. Some attempts have been made to establish a homogeneous group of stars which share the same common properties. Unfortunately, the flood of "new" information (e.g. UV and IR data) led again to a whole zoo of objects classified as lambda Bootes stars, which, however, are apparent non-members. To overcome this unsatisfying situation, a spectral atlas of well established lambda Bootes stars for the classical optical domain was compiled. It includes intermediate dispersion (40 and 120 Å mm^{-1}) spectra of three lambda Bootes, as well as appropriate MK standard stars. Furthermore, "suspicious" objects, such as shell and Field Horizontal Branch stars, have been considered in order to provide to classifiers a homogeneous reference. As a further step, a high resolution (8 Å mm^{-1}) spectrum of one "classical" lambda Bootes star in the same wavelength region (3800-4600 Å) is presented. In total, 55 lines can be used for this particular star to derive detailed abundances for nine heavy elements (Mg, Ca, Sc, Ti, Cr, Mn, Fe, Sr and Ba).
Heredia-De La Cruz, I.; /CINVESTAV, IPN
2011-09-01
A new measurement of the b {yields} {Lambda}{sub b} production fraction multiplied by the {Lambda}{sub b} {yields} J/{psi}{Lambda} branching fraction was performed by the D0 experiment using 6.1 fb{sup -1} of p{bar p} collisions at {radical}s = 1.96 TeV. The result of this measurement, f(b {yields} {Lambda}{sub b}) {center_dot} {Beta}({Lambda}{sub b} {yields} J/{psi}{Lambda}) = [6.01 {+-} 0.60 (stat.) {+-} 0.58 (syst.) {+-} 0.28 (PDG)] x 10{sup -5}, represents an improvement in precision by about a factor of three with respect to the current world average. We give an estimate of {Beta}({Lambda}{sub b} {yields} J/{psi}{Lambda}), which takes into account correlations among the different b-hadron production fractions and other weakly decaying baryons.
NASA Astrophysics Data System (ADS)
Abdou, M.; Baker, C.; Casini, G.
1991-07-01
The International Thermonuclear Experimental Reactor (ITER) was designed to operate in two phases. The first phase, which lasts for 6 years, is devoted to machine checkout and physics testing. The second phase lasts for 8 years and is devoted primarily to technology testing. This report describes the technology test program development for ITER, the ancillary equipment outside the torus necessary to support the test modules, the international collaboration aspects of conducting the test program on ITER, the requirements on the machine major parameters and the R and D program required to develop the test modules for testing in ITER.
Preparation and assay of phage lambda.
Dale, J W; Greenaway, P J
1985-01-01
Lambda, a temperate bacteriophage of E. coli, has two alternative modes of replication in sensitive cells, known as the lytic and lysogenic cycles. In the lytic cycle, after the lambda DNA enters the cells, various phage functions are expressed that result in the production of a large number of mature phage particles and cell lysis. In the lysogenic mode, which normally occurs in only a small proportion of the infected cells, the phage forms a more or less stable relationship with the host bacterium; this stable state is known as lysogeny. In a lysogenic cell, phage DNA is normally incorporated into the chromosomal DNA via specific attachment sites on both the phage DNA and the host chromosome. Replication of lambda DNA then occurs only during replication of the host chromosome, and the phage genome is inherited by each daughter cell at cell division. The phage is maintained in this prophage state through the action of a repressor protein, coded for by the phage gene cl. This repressor protein turns off the expression of virtually the whole of the lambda genome. If the repressor is inactivated, the expression of phage genes is initiated. This leads to the excision of lambda DNA from the host chromosome and entry into the lytic cycle. The balance between the lytic and lysogenic modes of replication is a delicate and complex one in which a key factor is the concentration of the cl gene product. Some of the many sources of further information about the basic biology of lambda phage are listed in the references to this chapter.
ERIC Educational Resources Information Center
Dobbs, David E.
2009-01-01
The main purpose of this note is to present and justify proof via iteration as an intuitive, creative and empowering method that is often available and preferable as an alternative to proofs via either mathematical induction or the well-ordering principle. The method of iteration depends only on the fact that any strictly decreasing sequence of…
The Lambda Orionis association. [star cluster anomalies
NASA Technical Reports Server (NTRS)
Murdin, P.; Penston, M. V.
1977-01-01
The Lambda Orionis association has the photometric properties of a typical young cluster with an age of about 4 million yr. Its distance is 400 + or - 40 pc. Attention is drawn to the lack of a dense molecular cloud and associated infrared sources in this young grouping
Analysis of the (1, lambda)-ES on the parabolic ridge.
Oyman, A I; Beyer, H G; Schwefel, H P
2000-01-01
The progress rate of the (1,+ lambda)-ES (Evolution Strategy) is analyzed on the parabolic ridge test function. A different progress behavior is observed for the (1, lambda)-ES than for the sphere model test function. The characteristics of the progress rate picture for the plus strategy differs little from the one obtained for the sphere model, but this strategy has drastically worse progress rate values than those obtained for the comma strategy. The dynamics of the distance to the progress axis is also investigated. A theoretical formula is derived to estimate the change in this distance over generations. This formula is used to derive the expected value of the problem-specific distance to the ridge axis. The correctness of the formulae is supported by simulation results.
Shoeb, Mohammad
2006-12-15
The energies of the degenerate spin-flip doublet (3{sup +}/2,5{sup +}/2) of {sub {lambda}}{sup 9}Be and of the 2{sup +} state of {sub {lambda}}{sub {lambda}}{sup 10}Be are analyzed in the {alpha} cluster model using a phenomenological dispersive three-body {lambda}{alpha}{alpha} force that reproduces the ground state energy of {sub {lambda}}{sup 9}Be. Two types of phenomenological {lambda}{alpha} and {alpha}{alpha} potentials and a few s-state {lambda}{lambda} potentials are taken as input. The energies of the excited states of the hypernuclei, treated as three- and four-body systems, calculated using the Variational Monte Carlo method, are in good agreement with the experimental values. Our results demonstrate that the existing data are insensitive to whether one employs a dispersive {lambda}{alpha}{alpha} force along with potentials in the relative angular momentum state l=0 and 2 as in the present work or whether one uses nonlocal {lambda}{alpha} potential as in earlier analyses.
Measurement of the Branching Fraction and Lambda-bar Polarization in B0 -> Lambda-par p pi-
Aubert, B.; Karyotakis, Y.; Lees, J.P.; Poireau, V.; Prencipe, E.; Prudent, X.; Tisserand, V.; Garra Tico, J.; Grauges, E.; Martinelli, M.; Palano, A.; Pappagallo, M.; Eigen, G.; Stugu, B.; Sun, L.; Battaglia, M.; Brown, D.N.; Kerth, L.T.; Kolomensky, Yu.G.; Lynch, G.; Osipenkov, I.L.; /LBL, Berkeley /UC, Berkeley /Birmingham U. /Ruhr U., Bochum /British Columbia U. /Brunel U. /Novosibirsk, IYF /UC, Irvine /UC, Riverside /UC, San Diego /UC, Santa Barbara /UC, Santa Cruz /Caltech /Cincinnati U. /Colorado U. /Colorado State U. /Dortmund U. /Dresden, Tech. U. /Ecole Polytechnique /Edinburgh U. /INFN, Ferrara /Ferrara U. /INFN, Ferrara /INFN, Ferrara /Ferrara U. /INFN, Ferrara /INFN, Ferrara /Ferrara U. /Frascati /INFN, Genoa /Genoa U. /INFN, Genoa /INFN, Genoa /Genoa U. /INFN, Genoa /INFN, Genoa /Genoa U. /Harvard U. /Heidelberg U. /Humboldt U., Berlin /Imperial Coll., London /Iowa U. /Iowa State U. /Johns Hopkins U. /Orsay, LAL /LLNL, Livermore /Liverpool U. /Queen Mary, U. of London /Royal Holloway, U. of London /Louisville U. /Mainz U., Inst. Kernphys. /Manchester U. /Maryland U. /Massachusetts U., Amherst /MIT, LNS /McGill U. /INFN, Milan /Milan U. /INFN, Milan /INFN, Milan /Milan U. /Mississippi U. /Montreal U. /Mt. Holyoke Coll. /INFN, Naples /Naples U. /INFN, Naples /INFN, Naples /Naples U. /NIKHEF, Amsterdam /Notre Dame U. /Ohio State U. /Oregon U. /INFN, Padua /Padua U. /INFN, Padua /INFN, Padua /Padua U. /Paris U., VI-VII /Pennsylvania U. /INFN, Perugia /Perugia U. /INFN, Pisa /Pisa U. /INFN, Pisa /Pisa, Scuola Normale Superiore /INFN, Pisa /Pisa U. /INFN, Pisa /Princeton U. /INFN, Rome /INFN, Rome /Rome U. /INFN, Rome /INFN, Rome /Rome U. /INFN, Rome /INFN, Rome /Rome U. /INFN, Rome /INFN, Rome /Rome U. /INFN, Rome /Rostock U. /Rutherford /DAPNIA, Saclay /SLAC /South Carolina U. /Stanford U., Phys. Dept. /SUNY, Albany /Tel Aviv U. /Tennessee U. /Texas U. /Texas U., Dallas /INFN, Turin /Turin U. /INFN, Trieste /Trieste U. /Valencia U., IFIC /Victoria U. /Warwick U. /Wisconsin U., Madison
2009-08-03
We present a measurement of the B{sup 0} {yields} {bar {Lambda}}p{pi}{sup -} branching fraction performed using the BABAR detector at the PEP-II asymmetric e{sup +}e{sup -} collider. Based on a sample of 467 x 10{sup 6} B{bar B} pairs we measure {Beta}(B{sup 0} {yields} {bar {Lambda}}p{pi}{sup -}) [3.07 {+-} 0.31(stat.) {+-} 0.23(syst.)] x 10{sup -6}. The measured differential spectrum as a function of the dibaryon invariant mass m({bar {Lambda}}p) shows a near-threshold enhancement similar to that observed in other baryonic B decays. We study the {bar {Lambda}} polarization as a function of {bar {Lambda}} energy in the B{sup 0} rest frame (E*{sub {bar {Lambda}}}) and compare it with theoretical expectations of fully longitudinally right-polarized {bar {Lambda}} at large E*{sub {bar {Lambda}}}.
Link, J.M.; Yager, P.M.; Anjos, J.C.; Bediaga, I.; Castromonte, C.; Machado, A.A.; Magnin, J.; Massafferri, A.; de Miranda, J.M.; Pepe, I.M.; Polycarpo, E.; dos Reis, A.C.; Carrillo, S.; Casimiro, E.; Cuautle, E.; Sanchez-Hernandez, A.; Uribe, C.; Vazquez, F.; Agostino, L.; Cinquini, L.; Cumalat, J.P.; /Colorado U. /Fermilab /Frascati /Guanajuato U. /Illinois U., Urbana /Indiana U. /Korea U. /Kyungpook Natl. U. /INFN, Milan /Milan U. /North Carolina U. /Pavia U. /INFN, Pavia /Rio de Janeiro, Pont. U. Catol. /Puerto Rico U., Mayaguez /South Carolina U. /Tennessee U. /Vanderbilt U. /Wisconsin U., Madison
2005-09-01
Using data from the FOCUS (E831) experiment at Fermilab, we present a new measurement of the weak decay-asymmetry parameter a{sub {Lambda}{sub c}} in {Lambda}{sub c}{sup +} {yields} {Lambda}{pi}{sup +} decay. Comparing particle with antiparticle decays, we obtain the first measurement of the CP violation parameter {Alpha} {triple_bond} a{sub {Lambda}{sub c}} + a{sub {ovr {Lambda}{sub c}}}/a{sub {Lambda}{sub c}} - a{sub {ovr {Lambda}{sub c}}}. We obtain a{sub {Lambda}{sub c}} = -0.78 {+-} 0.16 {+-} 0.13 and {Alpha} = -0.07 {+-} 0.19 {+-} 0.12 where errors are statistical and systematic.
Perl Modules for Constructing Iterators
NASA Technical Reports Server (NTRS)
Tilmes, Curt
2009-01-01
The Iterator Perl Module provides a general-purpose framework for constructing iterator objects within Perl, and a standard API for interacting with those objects. Iterators are an object-oriented design pattern where a description of a series of values is used in a constructor. Subsequent queries can request values in that series. These Perl modules build on the standard Iterator framework and provide iterators for some other types of values. Iterator::DateTime constructs iterators from DateTime objects or Date::Parse descriptions and ICal/RFC 2445 style re-currence descriptions. It supports a variety of input parameters, including a start to the sequence, an end to the sequence, an Ical/RFC 2445 recurrence describing the frequency of the values in the series, and a format description that can refine the presentation manner of the DateTime. Iterator::String constructs iterators from string representations. This module is useful in contexts where the API consists of supplying a string and getting back an iterator where the specific iteration desired is opaque to the caller. It is of particular value to the Iterator::Hash module which provides nested iterations. Iterator::Hash constructs iterators from Perl hashes that can include multiple iterators. The constructed iterators will return all the permutations of the iterations of the hash by nested iteration of embedded iterators. A hash simply includes a set of keys mapped to values. It is a very common data structure used throughout Perl programming. The Iterator:: Hash module allows a hash to include strings defining iterators (parsed and dispatched with Iterator::String) that are used to construct an overall series of hash values.
CO{sub 2} laser technology for advanced particle accelerators
Pogorelsky, I.V.; Van Steenbergen, A.; Fernow, R.; Kimura, W.D.; Bulanov, S.V.
1996-10-01
Short-pulse, high-power C0{sub 2} lasers open new prospects for development of high-gradient laser-driven electron accelerators. The advantages of {lambda}=10 {mu}m CO{sub 2} laser radiation over the more widely exploited solid state lasers with {lambda}{approx}1 {mu}m are based on a {lambda}{sup 2}-proportional ponderomotive potential, {lambda}-proportional phase slippage distance, and %-proportional scaling of the laser accelerator structures. We show how a picosecond terawatt C0{sub 2} laser that is under construction at the Brookhaven Accelerator Test Facility may benefit the ATFs experimental program of testing far-field, near-field, and plasma accelerator schemes.
The lambda point experiment in microgravity
NASA Technical Reports Server (NTRS)
Lipa, J. A.
1988-01-01
The motivation and potential for performing very high resolution measurements of the heat capacity singularity at the lambda point of helium in microgravity conditions was briefly discussed. It is clear that tests extending deep into the asymptotic region can be performed, where the theoretical predictions take on their simplest form. This advantageous situation should lead to a major improvement in the understanding of the range of applicability of current theoretical ideas in this field. The lambda transition holds out the prospect of giving the maximum advance of any system, and with the application of cryogenic techniques, the potential of this system can be realized. The technology for the initial experiments is already developed, and results could be obtained in 1990.
The {Lambda}(1405) in Full QCD
Menadue, Benjamin J.; Kamleh, Waseem; Leinweber, Derek B.; Mahbub, M. Selim
2011-12-14
At 1405.1 MeV, the lowest-lying negative-parity state of the {Lambda} baryon lies surprising low. Indeed, this is lower than the lowest negative-parity state of the nucleon, even though the {Lambda}(1405) possesses a valence strange quark. However, previous Lattice QCD studies have been unable to identify such a low-lying state. Using the PACS-CS (2+1)-flavour full-QCD ensembles, available through the ILDG, we utilise a variational analysis with source and sink smearing to isolate this elusive state. We find three low-lying odd-parity states, and for the first time reproduce the correct level ordering with respect to the nearby scattering thresholds.
Donne, A. J. H.; Hellermann, M. G. von; Barnsley, R.
2008-10-22
After an introduction into the specific challenges in the field of diagnostics for ITER (specifically high level of nuclear radiation, long pulses, high fluxes of particles to plasma facing components, need for reliability and robustness), an overview will be given of the spectroscopic diagnostics foreseen for ITER. The paper will describe both active neutral-beam based diagnostics as well as passive spectroscopic diagnostics operating in the visible, ultra-violet and x-ray spectral regions.
ITER convertible blanket evaluation
Wong, C.P.C.; Cheng, E.
1995-09-01
Proposed International Thermonuclear Experimental Reactor (ITER) convertible blankets were reviewed. Key design difficulties were identified. A new particle filter concept is introduced and key performance parameters estimated. Results show that this particle filter concept can satisfy all of the convertible blanket design requirements except the generic issue of Be blanket lifetime. If the convertible blanket is an acceptable approach for ITER operation, this particle filter option should be a strong candidate.
AN EXPRESSION TEMPLATE AWARE LAMBDA FUNCTION
S. A. SMITH; J. STRIEGNITZ
2000-09-19
The authors show how the paradigms of lambda functions and expression templates fit together in order to provide a means to increase the expressiveness of existing STL algorithms. They demonstrate how the expression templates approach could be extended in order to work with built-in types. To be portable, their solution is based on the Portable Expression Template Engine (PETE), which is a framework that enables the development of expression template aware classes.
NASA Astrophysics Data System (ADS)
Stambaugh, R. D.
2006-04-01
Stars are powered by fusion, the energy released by fusing together light nuclei, using gravitational confinement of plasma. Fusion on earth will be done in a 100 million degree plasma made of deuterium and tritium and confined by magnetic fields or inertia. The worldwide fusion research community will construct ITER, the first experiment that will burn a DT plasma by copious fusion reactions. ITER's nominal goal is to create 500 MW of fusion power. An energy gain of 10 will mean the plasma is dominantly self-heated by the fusion-produced alpha particles. ITER's all superconducting magnet technology and steady-state heat removal technology will enable nominal 400 s pulses to allow the study of burning plasmas on the longest intrinsic timescale of the confined plasma - diffusive redistribution of the electrical currents in the plasma. The advances in magnetic confinement physics that have led to this opportunity will be described, as well as the research opportunities afforded by ITER. The physics of confining stable plasmas and heating them will produce the high gain state in ITER. Sustained burn will come from the physics of controlling currents in plasmas and how the hot plasma is interfaced to its room temperature surroundings. ITER will provide our first experience with how fusion plasma self-heating will profoundly affect the complex, interlinked physical processes that occur in confined plasmas.
Usmani, A. A.; Hasan, Z.
2006-09-15
We present a fully correlated study of the six-body {sub {lambda}}{sub {lambda}}{sup 6}He hypernucleus. The wave function involves all relevant dynamic correlations as well as the space-exchange correlation (SEC). Calculations for energy breakdown, {lambda}{lambda}-separation energy, nuclear core polarization, and point proton radius have been performed. The baryon density profiles have also been calculated. Effect of SEC on all these physical observables is found to be significant. The findings suggest that a study ignoring SEC would be deficient.
Bobyshev, A.; Crawford, M.; DeMar, P.; Grigaliunas, V.; Grigoriev, M.; Moibenko, A.; Petravick, D.; Rechenmacher, R.; Newman, H.; Bunn, J.; Van Lingen, F.; Nae, D.; Ravot, S.; Steenberg, C.; Su, X.; Thomas, M.; Xia, Y.; /Caltech
2006-08-01
Lambda Station is an ongoing project of Fermi National Accelerator Laboratory and the California Institute of Technology. The goal of this project is to design, develop and deploy network services for path selection, admission control and flow based forwarding of traffic among data-intensive Grid applications such as are used in High Energy Physics and other communities. Lambda Station deals with the last-mile problem in local area networks, connecting production clusters through a rich array of wide area networks. Selective forwarding of traffic is controlled dynamically at the demand of applications. This paper introduces the motivation of this project, design principles and current status. Integration of Lambda Station client API with the essential Grid middleware such as the dCache/SRM Storage Resource Manager is also described. Finally, the results of applying Lambda Station services to development and production clusters at Fermilab and Caltech over advanced networks such as DOE's UltraScience Net and NSF's UltraLight is covered.
Trivalent Iron Induced Gelation in Lambda-Carrageenan
Running, Cordelia A.; Falshaw, Ruth; Janaswamy, Srinivas
2012-01-01
This communication reports gelation of lambda-carrageenan, for the first time, in the presence of trivalent iron ions. Kappa-, iota- and lambda-carrageenans are sulfated polysaccharides used extensively in food, pharmaceutical and medical applications. Kappa- and iota-carrageenans show gelation in the presence of mono- and di-valent ions, but lambda-carrageenan yields only viscous solutions. Our results show that gelation in lambda-carrageenan indeed is possible, but with trivalent ions. X-ray fiber diffraction patterns of iron (III)-lambda-carrageenan are characteristic of highly oriented and polycrystalline fibers containing well resolved Bragg reflections. The elastic modulus (G') of the product is far greater than the loss modulus (G") indicating the thermal stability of lambda-carrageenan in the presence of iron (III) ions. This novel finding has potential to expand lambda-carrageenan’s current utility beyond a viscosifying agent. PMID:22408280
Trivalent iron induced gelation in lambda-carrageenan
Running, Cordelia A.; Falshaw, Ruth; Janaswamy, Srinivas
2012-05-24
This communication reports gelation of lambda-carrageenan, for the first time, in the presence of trivalent iron ions. Kappa-, iota- and lambda-carrageenans are sulfated polysaccharides used extensively in food, pharmaceutical and medical applications. Kappa- and iota-carrageenans show gelation in the presence of mono- and di-valent ions, but lambda-carrageenan yields only viscous solutions. Our results show that gelation in lambda-carrageenan indeed is possible, but with trivalent ions. X-ray fiber diffraction patterns of iron (III)-lambda-carrageenan are characteristic of highly oriented and polycrystalline fibers containing well resolved Bragg reflections. The elastic modulus (G*) of the product is far greater than the loss modulus (G*) indicating the thermal stability of lambda-carrageenan in the presence of iron (III) ions. This novel finding has potential to expand lambda-carrageenan's current utility beyond a viscosifying agent.
MASS FUNCTION PREDICTIONS BEYOND {Lambda}CDM
Bhattacharya, Suman; Lukic, Zarija; Habib, Salman; Heitmann, Katrin; White, Martin; Wagner, Christian
2011-05-10
The statistics of dark matter halos is an essential component of precision cosmology. The mass distribution of halos, as specified by the halo mass function, is a key input for several cosmological probes. The sizes of N-body simulations are now such that, for the most part, results need no longer be statistics-limited, but are still subject to various systematic uncertainties. Discrepancies in the results of simulation campaigns for the halo mass function remain in excess of statistical uncertainties and of roughly the same size as the error limits set by near-future observations; we investigate and discuss some of the reasons for these differences. Quantifying error sources and compensating for them as appropriate, we carry out a high-statistics study of dark matter halos from 67 N-body simulations to investigate the mass function and its evolution for a reference {Lambda}CDM cosmology and for a set of wCDM cosmologies. For the reference {Lambda}CDM cosmology (close to WMAP5), we quantify the breaking of universality in the form of the mass function as a function of redshift, finding an evolution of as much as 10% away from the universal form between redshifts z = 0 and z = 2. For cosmologies very close to this reference we provide a fitting formula to our results for the (evolving) {Lambda}CDM mass function over a mass range of 6 x 10{sup 11}-3 x 10{sup 15} M{sub sun} to an estimated accuracy of about 2%. The set of wCDM cosmologies is taken from the Coyote Universe simulation suite. The mass functions from this suite (which includes a {Lambda}CDM cosmology and others with w {approx_equal} -1) are described by the fitting formula for the reference {Lambda}CDM case at an accuracy level of 10%, but with clear systematic deviations. We argue that, as a consequence, fitting formulae based on a universal form for the mass function may have limited utility in high-precision cosmological applications.
Lanczos iterated time-reversal.
Oberai, Assad A; Feijóo, Gonzalo R; Barbone, Paul E
2009-02-01
A new iterative time-reversal algorithm capable of identifying and focusing on multiple scatterers in a relatively small number of iterations is developed. It is recognized that the traditional iterated time-reversal method is based on utilizing power iterations to determine the dominant eigenpairs of the time-reversal operator. The convergence properties of these iterations are known to be suboptimal. Motivated by this, a new method based on Lanczos iterations is developed. In several illustrative examples it is demonstrated that for the same number of transmitted and received signals, the Lanczos iterations based approach is substantially more accurate. PMID:19206835
Differential Photoproduction Cross Sections of the Sigma0(1385), Lambda(1405), and Lambda(1520)
Moriya, Kei; Schumacher, Reinhard A.
2013-10-01
We report the exclusive photoproduction cross sections for the Sigma(1385), Lambda(1405), and Lambda(1520) in the reactions gamma + p -> K+ + Y* using the CLAS detector for energies from near the respective production thresholds up to a center-of-mass energy W of 2.85 GeV. The differential cross sections are integrated to give the total exclusive cross sections for each hyperon. Comparisons are made to current theoretical models based on the effective Lagrangian approach and fitted to previous data. The accuracy of these models is seen to vary widely. The cross sections for the Lambda(1405) region are strikingly different for the Sigma+pi-, Sigma0 pi0, and Sigma- pi+ decay channels, indicating the effect of isospin interference, especially at W values close to the threshold.
T(sub lambda) Depression by a Heat Current Along the lambda-Line
NASA Technical Reports Server (NTRS)
Liu, Yuanming; Larson, Melora; Iraelsson, Ulf E.
1999-01-01
We report measurements of the depression of the superfluid transition temperature by a heat current (1 less than or = Q less than or = 100 microW/sq cm) along the lambda-line (SVP less than or = P less than or = 21.6 bar). At P = 21.6 bar, measurements were also performed in a reduced gravity (0.2g). Experimental results show that the pressure dependence of the depression and the gravity effect on the measurements are small, in qualitative agreement with theoretical predictions. Keywords: superfluid helium; Lambda transition; heat current
Measurement of transverse {lambda} and {lambda}-bar polarization at COMPASS
Ferrero, A.
2007-06-13
New data on hyperon polarization in semi-inclusive deep inelastic scattering have been collected by the COMPASS collaboration at CERN during the years 2002-2004, using a beam of longitudinally polarized muons of 160 GeV/c and a 6LiD target that can be polarized both longitudinally and transversely. The various combinations of beam and target polarizations allow for the study of a wide variety of hyperon polarization effects. Here we present preliminary results on the transverse polarization of {lambda} and {lambda}-bar produced both with unpolarized and transversely polarized deuteron targets.
CO{sub 2} laser technology for advanced particle accelerators. Revision
Pogorelsky, I.V.
1996-06-01
Short-pulse, high-power CO{sub 2} lasers open new prospects for development of ultra-high gradient laser-driven electron accelerators. The advantages of {lambda}=10 {mu}m CO{sub 2} laser radiation over the more widely exploited solid state lasers with {lambda}{approximately}1 {mu}m are based on a {lambda}{sup 2}-proportional ponderomotive potential, {lambda}-proportional phase slippage distance, and {lambda}-proportional scaling of the laser accelerator structures. We show how a picosecond terawatt CO{sub 2} laser that is under construction at the Brookhaven Accelerator Test Facility may benefit the ATF`s experimental program of testing far-field, near-field, and plasma accelerator schemes.
Saadd, Y.
1994-12-31
In spite of the tremendous progress achieved in recent years in the general area of iterative solution techniques, there are still a few obstacles to the acceptance of iterative methods in a number of applications. These applications give rise to very indefinite or highly ill-conditioned non Hermitian matrices. Trying to solve these systems with the simple-minded standard preconditioned Krylov subspace methods can be a frustrating experience. With the mathematical and physical models becoming more sophisticated, the typical linear systems which we encounter today are far more difficult to solve than those of just a few years ago. This trend is likely to accentuate. This workshop will discuss (1) these applications and the types of problems that they give rise to; and (2) recent progress in solving these problems with iterative methods. The workshop will end with a hopefully stimulating panel discussion with the speakers.
Fourier mode analysis of source iteration in spatially periodic media
Zika, M.R.; Larsen, E.W.
1998-12-31
The standard Fourier mode analysis is an indispensable tool when designing acceleration techniques for transport iterations; however, it requires the assumption of a homogeneous infinite medium. For problems of practical interest, material heterogeneities may significantly impact iterative performance. Recent work has applied a Fourier analysis to the discretized two-dimensional transport operator with heterogeneous material properties. The results of these analyses may be difficult to interpret because the heterogeneity effects are inherently coupled to the discretization effects. Here, the authors describe a Fourier analysis of source iteration (SI) that allows the calculation of the eigenvalue spectrum for the one-dimensional continuous transport operator with spatially periodic heterogeneous media.
Rescheduling with iterative repair
NASA Technical Reports Server (NTRS)
Zweben, Monte; Davis, Eugene; Daun, Brian; Deale, Michael
1992-01-01
This paper presents a new approach to rescheduling called constraint-based iterative repair. This approach gives our system the ability to satisfy domain constraints, address optimization concerns, minimize perturbation to the original schedule, produce modified schedules, quickly, and exhibits 'anytime' behavior. The system begins with an initial, flawed schedule and then iteratively repairs constraint violations until a conflict-free schedule is produced. In an empirical demonstration, we vary the importance of minimizing perturbation and report how fast the system is able to resolve conflicts in a given time bound. We also show the anytime characteristics of the system. These experiments were performed within the domain of Space Shuttle ground processing.
Rabi resonances in the {lambda} excitation scheme
Godone, Aldo; Micalizio, Salvatore; Levi, Filippo
2002-12-01
We consider the interaction of a three-level system with phase-modulated resonant fields in the {lambda} excitation scheme. We treat theoretically the case of a sinusoidal phase modulation, a phase step perturbation, and a stochastic phase modulation. The appearance of a Rabi resonance both in the spectrum of the optical transmitted signal (electromagnetically induced transparency) and in the spectrum of the microwave emission (coherent population trapping maser) is considered in detail. All the theoretical results are compared with the analogous ones reported for the two-level system and with our experimental observations obtained for the case of rubidium in a buffer gas.
{Lambda}(1520) photoproduction with Regge contribution
Nam, Seung-il; Yu, Byung-Geel; Kao, Chung-Wen
2011-10-21
In this talk, we report our recent progresses on the {Lambda}(1520) photoproduction using the effective Lagrangian approach. In addition to the tree-level Born diagrams, we take into account the Regge-trajectories for the possible strange-meson exchanges in the t channel. We compute the angular and energy dependences of the production process, including polarization observables, such as the photon-beam asymmetry and the polarization-transfer coefficients, resulting in good qualitative agreement with current experimental data. We also compute the K{sup -} angle distribution function in the Gottfried-Jackson frame, using the polarization-transfer coefficients in the z direction.
Dr. Norbert Holtkamp
2016-07-12
ITER (in Latin âthe wayâ) is designed to demonstrate the scientific and technological feasibility of fusion energy. Fusion is the process by which two light atomic nuclei combine to form a heavier over one and thus release energy. In the fusion process two isotopes of hydrogen â deuterium and tritium â fuse together to form a helium atom and a neutron. Thus fusion could provide large scale energy production without greenhouse effects; essentially limitless fuel would be available all over the world. The principal goals of ITER are to generate 500 megawatts of fusion power for periods of 300 to 500 seconds with a fusion power multiplication factor, Q, of at least 10. Q ? 10 (input power 50 MW / output power 500 MW). The ITER Organization was officially established in Cadarache, France, on 24 October 2007. The seven members engaged in the project â China, the European Union, India, Japan, Korea, Russia and the United States â represent more than half the worldâs population. The costs for ITER are shared by the seven members. The cost for the construction will be approximately 5.5 billion Euros, a similar amount is foreseen for the twenty-year phase of operation and the subsequent decommissioning.
ERIC Educational Resources Information Center
Muench, Donald L.
2007-01-01
The problem of angle trisection continues to fascinate people even though it has long been known that it can't be done with straightedge and compass alone. However, for practical purposes, a good iterative procedure can get you as close as you want. In this note, we present such a procedure. Using only straightedge and compass, our procedure…
Duff, I.
1994-12-31
This workshop focuses on kernels for iterative software packages. Specifically, the three speakers discuss various aspects of sparse BLAS kernels. Their topics are: `Current status of user lever sparse BLAS`; Current status of the sparse BLAS toolkit`; and `Adding matrix-matrix and matrix-matrix-matrix multiply to the sparse BLAS toolkit`.
Hogan, J.T.; Uckan, N.A.
1990-01-01
The MHD stability limits to the ITER operational space have been examined with the PEST ideal stability code. Constraints on ITER operation have been examined for the nominal operational scenarios and for possible design variants. Rather than rely on evaluation of a relatively small number of sample cases, the approach has been to construct an approximation to the overall operational space, and to compare this with the observed limits in high-{beta} tokamaks. An extensive database with {approximately}20,000 stability results has been compiled for use by the ITER design team. Results from these studies show that the design values of the Troyon factor (g {approximately} 2.5 for ignition studies, and g {approximately} 3 for the technology phase) which are based on present experiments, are also expected to be attainable for ITER conditions, for which the configuration and wall-stabilisation environment differ from those in present experiments. Strongly peaked pressure profiles lead to degraded high-{beta} performance. Values of g {approximately} 4 are found for higher safety factor (q {sub {Psi}} {le} 4) than that of the present design (q{sub {Psi}} {approximately} 3). Profiles with q(0) < 1 are shown to give g {approximately} 2.5, if the current density profile provides optimum shear. The overall operational spaces are presented for g-q{sub {Psi}}, q{sub {Psi}}-1{sub i}, q-{alpha}{sub p} and l{sub i}-q{sub {psi}}.
The fluxonium as a lambda system
NASA Astrophysics Data System (ADS)
Vool, U.; Kou, A.; Smith, W. C.; Serniak, K.; Shankar, S.; Girvin, S. M.; Devoret, M. H.
A lambda system is a 3-level system in which two low-energy states can transition to a third higher-energy state by a coherent drive but not to each other. Lambda systems are commonly implemented in systems relying on atomic transitions. In the field of superconducting quantum circuits, the fluxonium qubit, an artificial atom consisting of a Josephson junction shunted by a super-inductance, is a unique artificial atom with highly non-linear energy levels. At half-flux quantum it has two low-energy states with a long energy lifetime, but it is difficult to perform fast quantum gates in this manifold. Employing the higher 2nd excited state as an intermediate level would be much more efficient. However, selection rules in the fluxonium qubit prohibit transitions between low-energy states and higher-energy states of the same parity. In this talk, we will introduce a way to create formerly forbidden transitions between levels of the fluxonium qubit - thus creating a more interesting artificial atom and a useful tool for future superconducting quantum circuits. Work supported by ARO, ONR, AFOSR and YINQE.
Consistency check of {Lambda}CDM phenomenology
Lombriser, Lucas
2011-03-15
The standard model of cosmology {Lambda}CDM assumes general relativity, flat space, and the presence of a positive cosmological constant. We relax these assumptions allowing spatial curvature, a time-dependent effective dark energy equation of state, as well as modifications of the Poisson equation for the lensing potential, and modifications of the growth of linear matter density perturbations in alternate combinations. Using six parameters characterizing these relations, we check {Lambda}CDM for consistency utilizing cosmic microwave background anisotropies, cross correlations thereof with high-redshift galaxies through the integrated Sachs-Wolfe effect, the Hubble constant, supernovae, and baryon acoustic oscillation distances, as well as the relation between weak gravitational lensing and galaxy flows. In all scenarios, we find consistency of the concordance model at the 95% confidence level. However, we emphasize that constraining supplementary background parameters and parametrizations of the growth of large-scale structure separately may lead to a priori exclusion of viable departures from the concordance model.
Yu, Shin-shan
2005-01-01
In this dissertation, we measure the properties of the lowest-mass beauty baryon, {Lambda}{sub b}. Baryons are the bound states of three quarks. Protons and neutrons, constituents of atomic nuclei, are the most common baryons. Other types of baryons can be produced and studied in the high-energy collider environment. Three-body dynamics makes baryons composed of low mass quarks difficult to study. On the other hand, baryons with one heavy quark simplify the theoretical treatment of baryon structure, since the heavy quark can be treated the same way as the nucleus in the atom. The {Lambda}{sub b} is composed of u, d, and b quarks, where the b quark is much heavier than the other two. Although, it is accessible, little is known about {Lambda}{sub b}. In 1991, UA1 [1] reconstructed 9 {+-} 1 {Lambda}{sub b} {yields} J/{Psi}{Lambda} candidates. In 1996, ALEPH and DELPHI reconstructed the decay {Lambda}{sub b} {yields} {Lambda}{sub c}{sup +}{pi}{sup -} and found only 3-4 candidates [2, 3]. ALEPH measured a {Lambda}{sub b} mass of 5614 {+-} 21 MeV/c{sup 2}, while DELPHI measured 5668 {+-} 18 MeV/c{sup 2}, about 2 {sigma} higher. Subsequently, CDF-I observed 20 {Lambda}{sub b} {yields} J/{Psi}{Lambda} events [4], confirmed the existence of {Lambda}{sub b} unambiguously and made a more precise measurement of {Lambda}{sub b} mass, 5621 {+-} 5 MeV/c{sup 2}. A recent CDF-II measurement by Korn [5] yields 5619.7 {+-} 1.7 MeV/c{sup 2}, which will significantly improve the current world average, 5624 {+-} 9 MeV/c{sup 2}, and resolve the discrepancy of ALEPH and DELPHI.
Charge-symmetry breaking {Lambda}-nucleon interaction
Bodmer, A.R.; Murali, M.; Usmani, Q.N.
1995-08-01
Some time ago we showed that the charge-symmetry-breaking interaction, as obtained from the mass four hypernuclei ({sub {Lambda}}{sup 4}H, {sub {Lambda}}{sup 4}He), was spin-independent; a result which cannot be understood with the conventional meson-exchange models. The calculations of ({sub {Lambda}}{sup 4}H, {sub {Lambda}}{sup 4}He) are currently being extended to include noncentral nuclear and hypernuclear forces which could modify this result. At a more fundamental level we intend to study quark-structure contributions to the charge-symmetry-breaking interaction.
Rare {Lambda}{sub b} decays in a quark model
Mott, L.; Roberts, W.
2010-08-05
Hadronic form factors for the rare weak transitions {Lambda}{sub b{yields}{Lambda}}{sup (*)} are calculated using a nonrelativistic quark model. The form factors obtained in this way are found to satisfy the relationships expecetd from the heavy quark effective theory. Differential decay rates and branching ratios are calculated for the dileptonic decays {Lambda}{sub b{yields}{Lambda}}{sup (*)}l{sup +}l{sup -}, for both ground state and excited daughter baryons. Inclusion of the long distance contributions from charmonium resonances significantly enhances the decay rates. Future work is outlined.
Analysis of the {Lambda}{sub b{yields}{Lambda}}l{sup +}l{sup -} decay in QCD
Aliev, T. M.; Savci, M.; Azizi, K.
2010-03-01
Taking into account the {Lambda} baryon distribution amplitudes and the most general form of the interpolating current of the {Lambda}{sub b}, the semileptonic {Lambda}{sub b{yields}{Lambda}}l{sup +}l{sup -} transition is investigated in the framework of the light cone QCD sum rules. Sum rules for all 12 form factors responsible for the {Lambda}{sub b{yields}{Lambda}}l{sup +}l{sup -} decay are constructed. The obtained results for the form factors are used to compute the branching fraction. A comparison of the obtained results with the existing predictions of the heavy quark effective theory is presented. The results of the branching ratio shows the detectability of this channel at the Large Hadron Collider beauty in the near future is quite high.
{lambda}N space-exchange correlation effects in the {sub {lambda}}{sup 5}He hypernucleus
Usmani, A.A.
2006-01-15
A complete realistic study of the {sub {lambda}}{sup 5}He hypernucleus is presented using a realistic Hamiltonian and a fully correlated wave function that takes into account all relevant dynamical correlations and {lambda}N space-exchange correlation (SEC). Results are sensitive to SEC, which significantly affects energy breakdown, {lambda}-separation energy, nuclear core polarization, point proton radius, and density profiles.
QCD factorization for {Lambda}{sub b}{sup 0}{yields}{Lambda}{sub c}{sup +}{pi}{sup -}
Zhang Zhenhua; Guo Xinheng; Lue Gang
2011-02-01
We prove that in the limit m{sub b},m{sub c}{yields}{infinity}, with m{sub c}/m{sub b} fixed, factorization holds at order {alpha}{sub s} for the decay {Lambda}{sub b}{sup 0}{yields}{Lambda}{sub c}{sup +}{pi}{sup -}. This proof is done in the infinite-momentum frame in which the momenta of {pi}, {Lambda}{sub c}, and {Lambda}{sub b} go to infinity. Our result is renormalization-scale- and scheme-independent at O({alpha}{sub s}). This is the same as the QCD factorization for B{yields}D{pi}.
Environmental chemistry, ecotoxicity, and fate of lambda-cyhalothrin.
He, Li-Ming; Troiano, John; Wang, Albert; Goh, Kean
2008-01-01
Lambda-cyhalothrin is a pyrethroid insecticide used for controlling pest insects in agriculture, public health, and in construction and households. Lambda-cyhalothrin is characterized by low vapor pressure and a low Henry's law constant but by a high octanol-water partition coefficient (K(ow)) and high water-solid-organic carbon partition coefficient (K(oc)) values. Lambda-cyhalothrin is quite stable in water at pH < 8, whereas it hydrolyzes to form HCN and aldehyde under alkaline conditions. Although lambda-cyhalothrin is relatively photostable under natural irradiation, with a half-life > 3 wk, its photolysis process is fast under UV irradiation, with a half-life < 10 min. The fate of lambda-cyhalothrin in aquatic ecosystems depends on the nature of system components such as suspended solids (mineral and organic particulates) and aquatic organisms (algae, macrophytes, or aquatic animals). Lambda-cyhalothrin residues dissolved in water decrease rapidly if suspended solids and/or aquatic organisms are present because lambda-cyhalothrin molecules are strongly adsorbed by particulates and plants. Adsorbed lambda-cyhalothrin molecules show decreased degradation rates because they are less accessible to breakdown than free molecules in the water column. On the other hand, lambda-cyhalothrin adsorbed to suspended solids or bottom sediments may provide a mechanism to mitigate its acute toxicity to aquatic organisms by reducing their short-term bioavailability in the water column. The widespread use of lambda-cyhalothrin has resulted in residues in sediment, which have been found to be toxic to aquatic organisms including fish and amphipods. Mitigation measures have been used to reduce the adverse impact of lambda-cyhalothrin contributed from agricultural or urban runoff. Mitigation may be achieved by reducing the quantity of runoff and suspended solid content in runoff through wetlands, detention ponds, or vegetated ditches. PMID:18418954
Interferons lambda, new cytokines with antiviral activity.
Lopušná, K; Režuchová, I; Betáková, T; Skovranová, L; Tomašková, J; Lukáčiková, L; Kabát, P
2013-01-01
Interferons (IFNs) are key cytokines in the establishment of a multifaceted antiviral response. Three distinct types of IFNs are now recognized (type I, type II, and type III) based on their receptor usage, structural features and biological activities. Although all IFNs are important mediators of antiviral protection, their roles in antiviral defence vary. Interferon lambda (IFN-λ) is a recently discovered group of small helical cytokines capable of inducing an antiviral response both in vitro as well as in vivo. They were discovered independently in 2003 by the groups of Sheppard and Kotenko. This family consists of three structurally related IFN-λ subtypes called IFN-λ1 (IL-29), IFN-λ2 (IL-28A), and IFN-λ3 (IL-28B). In this study we investigate the antiviral activities of IFN-λ1, λ2, and λ3 on some medically important viruses, influenza viruses, herpes viruses and lymphocytic choriomeningitis virus. PMID:23600875
Image reconstruction via truncated lambda tomography
NASA Astrophysics Data System (ADS)
Yu, Hengyong; Ye, Yangbo; Wang, Ge
2006-08-01
This paper investigates the feasibility of reconstructing a Computed Tomography (CT) image from truncated Lambda Tomography (LT), a gradient-like image of it's original. An LT image can be regarded as a convolution of the object image and the point spread function (PSF) of the Calderon operator. The PSF's infinite support provides the LT image infinite support; even the original CT image is of compact support. When the support of a truncated LT image fully covers the compact support of the corresponding CT image, we develop an extrapolation method to recover the CT image more precisely. When the support of the CT image fully covers the support of the truncated LT image, we design a template-based scheme to compensate the cupping effects and reconstruct a satisfactory image. Our algorithms are evaluated in numerical simulations and the results demonstrate the feasibilities of our methods. Our approaches provide a new way to reconstruct high-quality CT images.
Barnes, C.W.; Loughlin, M.J.; Nishitani, Takeo
1996-04-29
There are three primary goals for the Neutron Activation system for ITER: maintain a robust relative measure of fusion power with stability and high dynamic range (7 orders of magnitude); allow an absolute calibration of fusion power (energy); and provide a flexible and reliable system for materials testing. The nature of the activation technique is such that stability and high dynamic range can be intrinsic properties of the system. It has also been the technique that demonstrated (on JET and TFTR) the highest accuracy neutron measurements in DT operation. Since the gamma-ray detectors are not located on the tokamak and are therefore amenable to accurate characterization, and if material foils are placed very close to the ITER plasma with minimum scattering or attenuation, high overall accuracy in the fusion energy production (7--10%) should be achievable on ITER. In the paper, a conceptual design is presented. A system is shown to be capable of meeting these three goals, also detailed design issues remain to be solved.
The production of generalized transducing phage by bacteriophage lambda.
Sternberg, N
1986-01-01
Generalized transduction has for about 30 years been a major tool in the genetic manipulation of bacterial chromosomes. However, throughout that time little progress has been made in understanding how generalized transducing particles are produced. The experiments presented in this paper use phage lambda to assess some of the factors that affect that process. The results of those experiments indicate: the production of generalized transducing particles by bacteriophage lambda is inhibited by the phage lambda exonuclease (Exo). Also inhibited by lambda Exo is the production of lambda docR particles, a class of particles whose packaging is initiated in bacterial DNA and terminated at the normal phage packaging site, cos. In contrast, the production of lambda docL particles, a class of particles whose packaging is initiated at cos and terminated in bacterial DNA, is unaffected by lambda Exo; lambda-generalized transducing particles are not detected in induced lysis-defective (S-) lambda lysogens until about 60-90 min after prophage induction. Since wild-type lambda would normally lyse cells by 60 min, the production of lambda-generalized transducing particles depends on the phage being lysis-defective; if transducing lysates are prepared by phage infection then the frequency of generalized transduction for different bacterial markers varies over a 10-20-fold range. In contrast, if transducing lysates are prepared by the induction of a lambda lysogen containing an excision-defective prophage, then the variation in transduction frequency is much greater, and markers adjacent to, and on both sides of, the prophage are transduced with much higher frequencies than are other markers; if the prophage is replication-defective then the increased transduction of prophage-proximal markers is eliminated; measurements of total DNA in induced lysogens indicate that part of the increase in transduction frequency following prophage induction can be accounted for by an increase in the
Lineshape of the Lambda(1405) measured at CLAS
Kei Moriya, Reinhard Schumacher, CLAS Collaboration
2012-04-01
The {Lambda}(1405) has been a subject of controversy for decades, and its nature as a hyperon resonance has yet to be established firmly. Its peculiar lineshape, i.e., its {Sigma}{pi} invariant mass spectrum has lead to various theoretical studies, and some of these show that it may possess strong dynamical components which are not seen in other well-known baryons. With the CLAS detector system in Hall B at Jefferson Lab, we have measured the photoproduction reaction {gamma} + p {yields} K{sup +} {Lambda}(1405) with high statistics over different {Sigma}{pi} decay channels. The reconstructed invariant mass distribution has been measured, as well as the differential cross sections for the nearby {Lambda}(1405), {Sigma}(1385), and {Lambda}(1520). Our analysis method is discussed and our near-final results for the {Lambda}(1405) lineshape is presented.
Properties of the Lambda(1405) Measured at CLAS
Kei Moriya, Reinhard Schumacher
2012-04-01
The nature of the {Lambda}(1405), and its place in the baryon spectrum has remained uncertain for decades. Theoretical studies have shown that it may possess strong dynamical components which are not seen in other well-known baryons. Using the CLAS detector system in Hall B at Jefferson Lab, we have measured the photoproduction reaction {gamma} + p {yields} K{sup +} {Lambda}(1405) with high statistics and over different {Sigma}{pi} decay channels. The reconstructed invariant mass distribution (lineshape) has been measured, as well as the differential cross sections for the {Lambda}(1405), {Sigma}(1385), and {Lambda}(1520). Our analysis method is discussed and our near-final results for the {Lambda}(1405) lineshape and differential cross section are presented.
Phillips' Lambda function: Data summary and physical model
NASA Astrophysics Data System (ADS)
Irisov, V.; Plant, W.
2016-03-01
Measurements of Phillips' Lambda function describing the average length of breakers on the ocean per unit area at speed cb are summarized. An expression is developed that fits these data within reasonable bounds. A physical model for the Lambda function is derived based on the assumption that breaking occurs when the surface steepness exceeds a threshold value. The energy contained in the breaking region is related to the fifth power of the breaker speed, as Phillips showed, and from this the probability of finding a breaker with a speed cb may be determined from a simulation of the long-wave surface based on a linear superposition of Fourier components. This probability is directly related to the Lambda function so that a form for this function can be determined. The Lambda function so determined agrees in both shape and intensity with the fit to the measured Lambda functions.
Simple model for lambda-doublet propensities in bimolecular reactions
NASA Technical Reports Server (NTRS)
Bronikowski, Michael J.; Zare, Richard N.
1990-01-01
A simple geometric model is presented to account for lambda-doublet propensities in bimolecular reactions A + BC - AB + C. It applies to reactions in which AB is formed in a pi state, and in which the unpaired molecular orbital responsible for lambda-doubling arises from breaking the B-C bond. The lambda-doublet population ratio is predicted to be 2:1 provided that: (1) the motion of A in the transition state determines the plane of rotation of AB; (2) the unpaired pi orbital lying initially along the B-C bond may be resolved into a projection onto the AB plane of rotation and a projection perpendicular to this plane; (3) there is no preferred geometry for dissociation of ABC. The 2:1 lambda-doublet ratio is the 'unconstrained dynamics prior' lambda-doublet distribution for such reactions.
High Resolution Spectroscopy of 16N_Lambda by Electroproduction
Cusanno, Francesco; Urciuoli, Guido; Acha Quimper, Armando; Ambrozewicz, Pawel; Aniol, Konrad; Baturin, Pavlo; Bertin, Pierre; Benaoum, Hachemi; Blomqvist, Ingvar; Boeglin, Werner; Breuer, Herbert; Brindza, Paul; Bydzovsky, Petr; Camsonne, Alexandre; Chang, C.; Chang, C.C.; Chang, C.; Chang, C.C.; Chang, C.; Chang, C.C.; Chang, C.; Chang, C.C.; Chen, Jian-Ping; Choi, Seonho; Chudakov, Eugene; Cisbani, Evaristo; Colilli, Stefano; Coman, Luminita; Craver, Brandon; de Cataldo, Giacinto; De Jager, Cornelis; De Leo, Raffaele; Deur, Alexandre; Ferdi, Catherine; Feuerbach, Robert; Folts, Edward; Frullani, Salvatore; Garibaldi, Franco; Gayou, Olivier; Giuliani, Fausto; Gomez, Javier; Gricia, Massimo; Hansen, Jens-Ole; Hayes, David; Higinbotham, Douglas; Holmstrom, Timothy; Hyde, Charles; Ibrahim, Hassan; Iodice, Mauro; Jiang, Xiaodong; Kaufman, Lisa; Kino, Kouichi; Kross, Brian; Lagamba, Luigi; LeRose, John; Lindgren, Richard; Lucentini, Maurizio; Margaziotis, Demetrius; Markowitz, Pete; Marrone, Stefano; Meziani, Zein-Eddine; McCormick, Kathy; Michaels, Robert; Millener, D.; Miyoshi, Toshinobu; Moffit, Bryan; Monaghan, Peter; Moteabbed, Maryam; Munoz Camacho, Carlos; Nanda, Sirish; Nappi, E.; Nelyubin, Vladimir; Norum, Blaine; Okasyasu, Y.; Paschke, Kent; Perdrisat, Charles; Piasetzky, Eliazer; Punjabi, Vina; Qiang, Yi; Raue, Brian; Reimer, Paul; Reinhold, Joerg; Reitz, Bodo; Roche, Rikki; Rodriguez, Victor; Saha, Arunava; Santavenere, Fabio; Sarty, Adam; Segal, John; Shahinyan, Albert; Singh, Jaideep; Sirca, Simon; Snyder, Ryan; Solvignon, Patricia; Sotona, M.; Sotona, Miloslav; Sotona, M.; Sotona, Miloslav; Sotona, M.; Sotona, Miloslav; Sotona, M.; Sotona, Miloslav; Subedi, Ramesh; Sulkosky, Vince; Sulkosky, Vincent; Sulkosky, Vince; Sulkosky, Vincent; Suzuki, Tomokazu; Ueno, Hiroaki; Ulmer, Paul; Veneroni, P.P.; Voutier, Eric; Wojtsekhowski, Bogdan; Zeng, X.; Zorn, Carl
2009-01-01
An experimental study of the 16O(e, e'K+)16N_Lambda reaction has been performed at Jefferson Lab. A thin film of falling water was used as a target. This permitted a simultaneous measurement of the p(e, e'K+)Lambda,Sigma_0 exclusive reactions and a precise calibration of the energy scale. A ground-state binding energy of 13.76 Â± 0.16 MeV was obtained for 16N_Lambda with better precision than previous measurements on the mirror hypernucleus 16O_Lambda. Precise energies have been determined for peaks arising from a Lambda in s and p orbits coupled to the p1/2 and p3/2 hole states of the 15N core nucleus.
Abazov, Victor Mukhamedovich; Abbott, Braden Keim; Acharya, Bannanje Sripath; Adams, Mark Raymond; Adams, Todd; Alexeev, Guennadi D.; Alkhazov, Georgiy D.; Alton, Andrew K.; Alverson, George O.; Alves, Gilvan Augusto; Ancu, Lucian Stefan; /Nijmegen U. /Fermilab
2011-05-01
The {Lambda}{sub b}(udb) baryon is observed in the decay {Lambda}{sub b} {yields} J/{psi}{Lambda} using 6.1 fb{sup -1} of p{bar p} collisions collected with the D0 detector at {radical}s = 1.96 TeV. The production fraction multiplied by the branching fraction for this decay relative to that for the decay B{sup 0} {yields} J/{psi}K{sub s}{sup 0} is measured to be 0.345 {+-} 0.034 (stat.) {+-} 0.033 (syst.) {+-} 0.003 (PDG). Using the world average value of f(b {yields} B{sup 0}) {center_dot} {Beta}(B{sup 0} {yields} J/{psi}K{sub s}{sup 0}) = (1.74 {+-} 0.08) x 10{sup -5}, they obtain f(b {yields} {Lambda}{sub b}) {center_dot} {Beta}({Lambda}{sub b} {yields} J/{psi}{Lambda}) = (6.01 {+-} 0.60 (stat.) {+-} 0.58 (syst.) {+-} 0.28 (PDG)) x 10{sup -5}. This measurement represents an improvement in precision by about a factor of three with respect to the current world average.
Wang, M.-Z.; Lee, Y.-J.; Chao, Y.; Chen, K.-F.; Hou, W.-S.; Hsiung, Y. B.; Lin, S.-W.; Ueno, K.; Abe, K.; Hoshi, Y.; Adachi, I.; Haba, J.; Hazumi, M.; Itoh, R.; Iwasaki, Y.; Katayama, N.; Kichimi, H.; Krokovny, P.; Nakao, M.; Nishida, S.
2007-09-01
We study the following charmless baryonic three-body decays of B mesons: B{sup +}{yields}p{lambda}{gamma}, B{sup +}{yields}p{lambda}{pi}{sup 0}, and B{sup 0}{yields}p{lambda}{pi}{sup -}. The partial branching fractions as a function of the baryon-antibaryon mass and the polar angle distributions of the proton in the baryon-antibaryon system are presented. This study includes the first observation of B{sup +}{yields}p{lambda}{pi}{sup 0}, which is measured to have a branching fraction of (3.00{sub -0.53}{sup +0.61}{+-}0.33)x10{sup -6}. We also set upper limits on branching fractions of the two-body decays B{sup 0}{yields}p{sigma}*{sup -}, B{sup 0}{yields}{delta}{sup 0}{lambda}, B{sup +}{yields}p{sigma}*{sup 0}, and B{sup +}{yields}{delta}{sup +}{lambda} at the 90% confidence level. These results are obtained from a 414 fb{sup -1} data sample collected near the {upsilon}(4S) resonance with the Belle detector at the KEKB asymmetric-energy e{sup +}e{sup -} collider.
Tertiary structure of human {Lambda}6 light chains.
Pokkuluri, P. R.; Solomon, A.; Weiss, D. T.; Stevens, F. J.; Schiffer, M.; Center for Mechanistic Biology and Biotechnology; Univ. of Tennessee Medical Center /Graduate School of Medicine
1999-01-01
AL amyloidosis is a disease process characterized by the pathologic deposition of monoclonal light chains in tissue. To date, only limited information has been obtained on the molecular features that render such light chains amyloidogenic. Although protein products of the major human V kappa and V lambda gene families have been identified in AL deposits, one particular subgroup--lambda 6--has been found to be preferentially associated with this disease. Notably, the variable region of lambda 6 proteins (V lambda 6) has distinctive primary structural features including the presence in the third framework region (FR3) of two additional amino acid residues that distinguish members of this subgroup from other types of light chains. However, the structural consequences of these alterations have not been elucidated. To determine if lambda 6 proteins possess unique tertiary structural features, as compared to light chains of other V lambda subgroups, we have obtained x-ray diffraction data on crystals prepared from two recombinant V lambda 6 molecules. These components, isolated from a bacterial expression system, were generated from lambda 6-related cDNAs cloned from bone marrow-derived plasma cells from a patient (Wil) who had documented AL amyloidosis and another (Jto) with multiple myeloma and tubular cast nephropathy, but no evident fibrillar deposits. The x-ray crystallographic analyses revealed that the two-residue insertion located between positions 68 and 69 (not between 66 and 67 as previously surmised) extended an existing loop region that effectively increased the surface area adjacent to the first complementarity determining region (CDR1). Further, an unusual interaction between the Arg 25 and Phe 2 residues commonly found in lambda 6 molecules was noted. However, the structures of V lambda 6 Wil and Jto also differed from each other, as evidenced by the presence in the latter of certain ionic and hydrophobic interactions that we posit increased protein
Accelerated expansion through interaction
Zimdahl, Winfried
2009-05-01
Interactions between dark matter and dark energy with a given equation of state are known to modify the cosmic dynamics. On the other hand, the strength of these interactions is subject to strong observational constraints. Here we discuss a model in which the transition from decelerated to accelerated expansion of the Universe arises as a pure interaction phenomenon. Various cosmological scenarios that describe a present stage of accelerated expansion, like the {lambda}CDM model or a (generalized) Chaplygin gas, follow as special cases for different interaction rates. This unifying view on the homogeneous and isotropic background level is accompanied by a non-adiabatic perturbation dynamics which can be seen as a consequence of a fluctuating interaction rate.
pp-bar->LAMBDA{sub c}LAMBDA-bar{sub c} within a Handbag Picture - Section and Spin Observables
Goritschnig, A. T.; Schweiger, W.; Kroll, P.
2009-08-04
We study the process pp-bar->LAMBDA{sub c}LAMBDA-bar{sub c} within the generalized parton picture. Our starting point is the double handbag diagram which factorizes into soft generalized parton distributions and a hard subprocess amplitude for uu-bar->cc-bar. Our cross-section predictions may become interesting in view of forthcoming experiments at FAIR in Darmstadt.
Computation of eigenpairs of Ax = lambda Bx for vibrations of spinning deformable bodies
NASA Technical Reports Server (NTRS)
Utku, S.; Clemente, J. L. M.
1984-01-01
It is shown that, when linear theory is used, the general eigenvalue problem related with the free vibrations of spinning deformable bodies is of the type AX = lambda Bx, where A is Hermitian, and B is real positive definite. Since the order n of the matrices may be large, and A and B are banded or block banded, due to the economics of the numerical solution, one is interested in obtaining only those eigenvalues which fall within the frequency band of interest of the problem. The paper extends the well known method of bisections and iteration of R to the n power to n dimensional complex spaces, i.e., to C to the n power, so that it can be applied to the present problem.
Aslam, M. Jamil; Wang Yuming; Lue Caidian
2008-12-01
The weak decays of {lambda}{sub b}{yields}{lambda}l{sup +}l{sup -} (l=e, {mu}) are investigated in the minimal supersymmetric standard model (MSSM) and also in supersymmetric (SUSY) SO(10) grand unified models. In the MSSM special attention is paid to the neutral Higgs bosons (NHBs) as they make quite a large contribution in exclusive B{yields}X{sub s}l{sup +}l{sup -} decays at large tan{beta} regions of parameter space of SUSY models, since part of SUSY contributions is proportional to tan{sup 3}{beta}. The analysis of decay rate, forward-backward asymmetries, lepton polarization asymmetries, and the polarization asymmetries of the {lambda} baryon in {lambda}{sub b}{yields}{lambda}l{sup +}l{sup -} show that the values of these physical observables are greatly modified by the effects of NHBs. In the SUSY SO(10) grand unified theory model, the new physics contribution comes from the operators which are induced by the NHBs' penguins and also from the operators having chirality opposite to that of the corresponding standard model (SM) operators. SUSY SO(10) effects show up only in the decay {lambda}{sub b}{yields}{lambda}+{tau}{sup +}{tau}{sup -} where the longitudinal and transverse lepton polarization asymmetries deviate significantly from the SM value while the effects in the decay rate, forward-backward asymmetries, and polarization asymmetries of final state {lambda} baryon are very mild. The transverse lepton polarization asymmetry in {lambda}{sub b}{yields}{lambda}+{tau}{sup +}{tau}{sup -} is almost zero in the SM and in the MSSM model. However, it can reach to -0.1 in the SUSY SO(10) grand unified theory model and could be seen at the future colliders; hence this asymmetry observable will provide us useful information to probe new physics and discriminate between different models.
Adaptive iterative reconstruction
NASA Astrophysics Data System (ADS)
Bruder, H.; Raupach, R.; Sunnegardh, J.; Sedlmair, M.; Stierstorfer, K.; Flohr, T.
2011-03-01
It is well known that, in CT reconstruction, Maximum A Posteriori (MAP) reconstruction based on a Poisson noise model can be well approximated by Penalized Weighted Least Square (PWLS) minimization based on a data dependent Gaussian noise model. We study minimization of the PWLS objective function using the Gradient Descent (GD) method, and show that if an exact inverse of the forward projector exists, the PWLS GD update equation can be translated into an update equation which entirely operates in the image domain. In case of non-linear regularization and arbitrary noise model this means that a non-linear image filter must exist which solves the optimization problem. In the general case of non-linear regularization and arbitrary noise model, the analytical computation is not trivial and might lead to image filters which are computationally very expensive. We introduce a new iteration scheme in image space, based on a regularization filter with an anisotropic noise model. Basically, this approximates the statistical data weighting and regularization in PWLS reconstruction. If needed, e.g. for compensation of the non-exactness of backprojector, the image-based regularization loop can be preceded by a raw data based loop without regularization and statistical data weighting. We call this combined iterative reconstruction scheme Adaptive Iterative Reconstruction (AIR). It will be shown that in terms of low-contrast visibility, sharpness-to-noise and contrast-to-noise ratio, PWLS and AIR reconstruction are similar to a high degree of accuracy. In clinical images the noise texture of AIR is also superior to the more artificial texture of PWLS.
Flame acceleration studies in the MINIFLAME facility
Tieszen, S.R.; Sherman, M.P.; Benedick, W.B.
1989-07-01
Flame acceleration and deflagration-to-detonation transition (DDT) studies have been conducted in a 19.4-cm high, 14.5-cm wide, and 2. 242-m long channel (MINIFLAME) that is a 1:12.6 scale model of the 136-m{sup 3} FLAME facility. Tests were conducted with two levels of hydrogen concentration -- 20% and 30%, with and without obstacles in the channel, and with three levels of transverse top venting -- 0%, 13%, and 50%. The flame acceleration results in MINIFLAME are qualitatively similar to those in FLAME; however, the small-scale results are more benign quantitatively. The results show that insufficient venting, 13% venting in this case, can promote flame acceleration due to turbulence produced by the flow through the vents in smooth channels. However, with obstacle-generated turbulence in the channel, 13% top venting was found to be beneficial. Flame acceleration resulting in DDT was shown to occur in as little as 35 liters of mixture. Comparison of the DDT data with obstacles in MINIFLAME and FLAME supports d/{lambda} scaling of DDT, where {lambda} is the detonation cell width of the mixture and d is the characteristic open diameter of the channel. In the MINIFLAME and FLAME tests, DDT occurred for d/{lambda} greater than approximately three. Comparison with other experiments shows that the value of d/{lambda} for DDT is not constant but depends on the obstacle type, spacing, and channel geometry. The comparison of MINIFLAME and FLAME experiments extends the use of d/{lambda} scaling to different geometries and larger scales than previous studies. Small-scale-model testing of flame acceleration and DDT with the same combustible mixture as the full-scale prototype underpredicts flame speeds, overpressures, and the possibility of DDT. 18 refs., 16 figs.
Quantum iterated function systems.
Łoziński, Artur; Zyczkowski, Karol; Słomczyński, Wojciech
2003-10-01
An iterated function system (IFS) is defined by specifying a set of functions in a classical phase space, which act randomly on an initial point. In an analogous way, we define a quantum IFS (QIFS), where functions act randomly with prescribed probabilities in the Hilbert space. In a more general setting, a QIFS consists of completely positive maps acting in the space of density operators. This formalism is designed to describe certain problems of nonunitary quantum dynamics. We present exemplary classical IFSs, the invariant measure of which exhibits fractal structure, and study properties of the corresponding QIFSs and their invariant states.
Iterative Magnetometer Calibration
NASA Technical Reports Server (NTRS)
Sedlak, Joseph
2006-01-01
This paper presents an iterative method for three-axis magnetometer (TAM) calibration that makes use of three existing utilities recently incorporated into the attitude ground support system used at NASA's Goddard Space Flight Center. The method combines attitude-independent and attitude-dependent calibration algorithms with a new spinning spacecraft Kalman filter to solve for biases, scale factors, nonorthogonal corrections to the alignment, and the orthogonal sensor alignment. The method is particularly well-suited to spin-stabilized spacecraft, but may also be useful for three-axis stabilized missions given sufficient data to provide observability.
MLP iterative construction algorithm
NASA Astrophysics Data System (ADS)
Rathbun, Thomas F.; Rogers, Steven K.; DeSimio, Martin P.; Oxley, Mark E.
1997-04-01
The MLP Iterative Construction Algorithm (MICA) designs a Multi-Layer Perceptron (MLP) neural network as it trains. MICA adds Hidden Layer Nodes one at a time, separating classes on a pair-wise basis, until the data is projected into a linear separable space by class. Then MICA trains the Output Layer Nodes, which results in an MLP that achieves 100% accuracy on the training data. MICA, like Backprop, produces an MLP that is a minimum mean squared error approximation of the Bayes optimal discriminant function. Moreover, MICA's training technique yields novel feature selection technique and hidden node pruning technique
[Extraction of lambda-cyhalothrin from aqueous dioxan solutions].
Shormanov, V K; Chigareva, E N; Belousova, O V
2011-01-01
The results of extraction of lambda-cigalotrin from dioxan aqueous solutions by hydrophobic organic solvents are presented. It is shown that the degree of extraction depends on the nature of the extractant, the water to dioxan ratio, and saturation of the water-dioxan layer with the electrolyte. The highest efficiency of lambda-cigalotrin extraction was achieved using chlorophorm as a solvent under desalination conditions. The extraction factor was calculated necessary to obtain the desired amount of lambda-cigalotrin from the water-dioxan solution (4:1) with the help of the extractants being used.
Acoustics of the Lambda Transition in Superfluid Helium
NASA Astrophysics Data System (ADS)
Megson, Peter; Meichle, David; Lathrop, Daniel
2014-11-01
Liquid Helium undergoes a phase transition and becomes a quantum superfluid when cooled below the Lambda transition temperature of 2.17 Kelvin. The superfluid, which is a partial Bose Einstein Condensate, exhibits unique macroscopic properties such as flow without viscosity and ballistic temperature propagation. We have recorded striking audio-frequency sounds using a micro electromechanical microphone (MEMS) present as the Helium goes through the Lambda transition. Characterization of this sound, as well as its relevance to theories of the Lambda transition will be presented.
Shoeb, Mohammad; Sonika
2009-08-15
The energies of the ground and excited 2{sup +} states of {sub {lambda}}{sub {lambda}}{sup 10}Be have been calculated variationally in the Monte Carlo framework. The hypernucleus is treated as a partial ten-body problem in the {lambda}{lambda}+{alpha}{alpha} model where nucleonic degrees of freedom of {alpha}'s are taken into consideration ignoring the antisymmetrization between two {alpha}'s. The central two-body {lambda}N and {lambda}{lambda} and the three-body dispersive and two-pion exchange {lambda}NN forces, constrained by the {lambda}p scattering data and the observed ground state energies of {sub {lambda}}{sup 5}He and {sub {lambda}}{sub {lambda}}{sup 6}He, are employed. The product-type trial wave function predicts binding energy for the ground state considerably less than for the event reported by Danysz et al.; however, it is consistent with the value deduced assuming a {gamma} ray of 3.04 MeV must have escaped undetected in the decay of the product {sub {lambda}}{sup 9}Be* {yields} {sub {lambda}}{sup 9}Be+{gamma} of the emulsion event {sub {lambda}}{sub {lambda}}{sup 10}Be{yields} {pi}{sup -}+p+{sub {lambda}}{sup 9}Be* and for the excited 2{sup +} state closer to the value measured in the Demachi-Yanagi event. The hypernucleus {sub {lambda}}{sub {lambda}}{sup 10}Be has an oblate shape in the excited state. These results are consistent with the earlier four-body {alpha} cluster model approach where {alpha}'s are assumed to be structureless entities.
Transverse equilibrium and stability of the primary beam in the plasma wake-field accelerator
Krall, J.; Joyce, G. )
1995-04-01
The primary electron beam in the plasma wake-field accelerator is studied, using multidimensional particle simulation, for cases in which a shaped electron beam is used, with length [ital L][gt][lambda][sub [ital p
Sidorin, Anatoly
2010-01-05
In linear accelerators the particles are accelerated by either electrostatic fields or oscillating Radio Frequency (RF) fields. Accordingly the linear accelerators are divided in three large groups: electrostatic, induction and RF accelerators. Overview of the different types of accelerators is given. Stability of longitudinal and transverse motion in the RF linear accelerators is briefly discussed. The methods of beam focusing in linacs are described.
Asymptotic iteration method for spheroidal harmonics of higher-dimensional Kerr-(A)dS black holes
Cho, H. T.; Cornell, A. S.; Doukas, Jason; Naylor, Wade
2009-09-15
In this work we calculate the angular eigenvalues of the (n+4)-dimensional simply rotating Kerr-(A)dS spheroidal harmonics using the asymptotic iteration method. We make some comparisons between this method and that of the continued fraction method and use the latter to check our results. We also present analytic expressions for the small rotation limit up to O(c{sup 3}) with the coefficient of each power up to O({alpha}{sup 2}), where c=a{omega} and {alpha}=a{sup 2}{lambda} (a is the angular velocity, {omega} the frequency, and {lambda} the cosmological constant)
Observation of the Baryonic B decay B0bar to Lambda_c^+ anti-Lambda K-
Lees, J.P.; Poireau, V.; Tisserand, V.; Garra Tico, J.; Grauges, E.; Martinelli, M.; Milanes, D.A.; Palano, A.; Pappagallo, M.; Eigen, G.; Stugu, B.; Sun, L.; Brown, D.N.; Kerth, L.T.; Kolomensky, Yu.G.; Lynch, G.; Koch, H.; Schroeder, T.; Asgeirsson, D.J.; Hearty, C.; Mattison, T.S.; /British Columbia U. /Brunel U. /Novosibirsk, IYF /UC, Irvine /UC, Riverside /UC, Santa Barbara /UC, Santa Cruz /Caltech /Cincinnati U. /Colorado U. /Colorado State U. /Dortmund U. /Dresden, Tech. U. /Ecole Polytechnique /Edinburgh U. /INFN, Ferrara /INFN, Ferrara /INFN, Ferrara /Ferrara U. /INFN, Ferrara /Ferrara U. /INFN, Ferrara /Ferrara U. /INFN, Ferrara /Ferrara U. /INFN, Ferrara /Ferrara U. /INFN, Ferrara /Ferrara U. /INFN, Ferrara /Ferrara U. /INFN, Ferrara /Frascati /INFN, Genoa /Genoa U. /INFN, Genoa /Genoa U. /INFN, Genoa /Genoa U. /INFN, Genoa /Genoa U. /INFN, Genoa /INFN, Genoa /Genoa U. /INFN, Genoa /Indian Inst. Tech., Guwahati /Harvard U. /Harvey Mudd Coll. /Heidelberg U. /Humboldt U., Berlin /Imperial Coll., London /Iowa State U. /Iowa State U. /Johns Hopkins U. /Orsay, LAL /LLNL, Livermore /Liverpool U. /Queen Mary, U. of London /Royal Holloway, U. of London /Louisville U. /Mainz U., Inst. Kernphys. /Manchester U., Comp. Sci. Dept. /Maryland U. /Massachusetts U., Amherst /MIT /McGill U. /INFN, Milan /Milan U. /INFN, Milan /Milan U. /INFN, Milan /INFN, Milan /Milan U. /INFN, Milan /Milan U. /INFN, Milan /Milan U. /Mississippi U. /Montreal U. /INFN, Naples /Naples U. /INFN, Naples /Naples U. /INFN, Naples /Naples U. /INFN, Naples /Naples U. /NIKHEF, Amsterdam /Notre Dame U. /Ohio State U. /Oregon U. /INFN, Padua /Padua U. /INFN, Padua /Padua U. /INFN, Padua /Padua U. /INFN, Padua /INFN, Padua /INFN, Padua /INFN, Padua /Padua U. /INFN, Padua /Padua U. /Paris U., VI-VII /INFN, Perugia /Perugia U. /INFN, Perugia /Perugia U. /INFN, Perugia /Perugia U. /INFN, Perugia /Perugia U. /INFN, Pisa /Pisa U. /INFN, Pisa /Pisa U. /INFN, Pisa /Pisa U. /INFN, Pisa /Pisa U. /Sassari U. /INFN, Pisa /Pisa U. /INFN, Pisa /Pisa U. /INFN, Pisa /Pisa U. /INFN, Pisa /Pisa U. /INFN, Pisa /Pisa, Scuola Normale Superiore /INFN, Pisa /Pisa U. /INFN, Pisa /Pisa U. /INFN, Pisa /INFN, Pisa /Pisa U. /INFN, Pisa /Princeton U. /INFN, Rome /INFN, Rome /INFN, Rome /Rome U. /INFN, Rome /INFN, Rome /Rome U. /INFN, Rome /Rome U. /INFN, Rome /INFN, Rome /INFN, Rome /Rostock U. /Rutherford /DAPNIA, Saclay /SLAC /South Carolina U. /Southern Methodist U. /Stanford U., Phys. Dept. /SUNY, Albany /Tel Aviv U. /Tennessee U. /Texas U. /Texas U., Dallas /INFN, Turin /Turin U. /INFN, Turin /Turin U. /INFN, Trieste /Trieste U. /INFN, Trieste /Trieste U. /Valencia U., IFIC /Victoria U. /Warwick U. /Wisconsin U., Madison
2011-11-08
The authors report the observation of the baryonic B decay {bar B}{sup 0} {yields} {Lambda}{sub c}{sup +} {bar {Lambda}}K{sup -} with a significance larger than 7 standard deviations based on 471 x 10{sup 6} B{bar B} pairs collected with the BABAR detector at the PEP-II storage ring at SLAC. They measure the branching fraction for the decay {bar B}{sup 0} {yields} {Lambda}{sub c}{sup +} {bar {Lambda}}K{sup -} to be (3.8 {+-} 0.8{sub stat} {+-} 0.2{sub sys} {+-} 1.0 {sub {Lambda}{sub c}{sup +}}) x 10{sup -5}. The uncertainties are statistical, systematic, and due to the uncertainty in the {Lambda}{sub c}{sup +} branching fraction. They find that the {Lambda}{sub c}{sup +} K{sup -} invariant mass distribution shows an enhancement above 3.5 GeV/c{sup 2}.
The First Generation of Stars in Lambda-CDM Cosmology
Gao, Liang; Abel, T.; Frenk, C.S.; Jenkins, A.; Springel, V.; Yoshida, N.; /Nagoya U.
2006-10-10
We have performed a large set of high-resolution cosmological simulations using smoothed particle hydrodynamics (SPH) to study the formation of the first luminous objects in the {Lambda}CDM cosmology. We follow the collapse of primordial gas clouds in eight early structures and document the scatter in the properties of the first star-forming clouds. Our first objects span formation redshifts from z {approx} 10 to z {approx} 50 and cover an order of magnitude in halo mass. We find that the physical properties of the central star-forming clouds are very similar in all of the simulated objects despite significant differences in formation redshift and environment. This suggests that the formation path of the first stars is largely independent of the collapse redshift; the physical properties of the clouds have little correlation with spin, mass, or assembly history of the host halo. The collapse of proto-stellar objects at higher redshifts progresses much more rapidly due to the higher densities, which accelerates the formation of molecular hydrogen, enhances initial cooling and shortens the dynamical timescales. The mass of the star-forming clouds cover a broad range, from a few hundred to a few thousand solar masses, and exhibit various morphologies: some have disk-like structures which are nearly rotational supported; others form flattened spheroids; still others form bars. All of them develop a single protostellar ''seed'' which does not fragment into multiple objects up to the moment that the central gas becomes optically thick to H{sub 2} cooling lines. At this time, the instantaneous mass accretion rate onto the centre varies significantly from object to object, with disk-like structures having the smallest mass accretion rates. The formation epoch and properties of the star-forming clouds are sensitive to the values of cosmological parameters.
Darbos, C.; Henderson, M.; Gandini, F.; Albajar, F.; Bomcelli, T.; Heidinger, R.; Saibene, G.; Chavan, R.; Goodman, T.; Hogge, J. P.; Sauter, O.; Denisov, G.; Farina, D.; Kajiwara, K.; Kasugai, A.; Kobayashi, N.; Oda, Y.; Ramponi, G.
2009-11-26
A 26 MW Electron Cyclotron Heating and Current Drive (EC H and CD) system is to be installed for ITER. The main objectives are to provide, start-up assist, central H and CD and control of MHD activity. These are achieved by a combination of two types of launchers, one located in an equatorial port and the second type in four upper ports. The physics applications are partitioned between the two launchers, based on the deposition location and driven current profiles. The equatorial launcher (EL) will access from the plasma axis to mid radius with a relatively broad profile useful for central heating and current drive applications, while the upper launchers (ULs) will access roughly the outer half of the plasma radius with a very narrow peaked profile for the control of the Neoclassical Tearing Modes (NTM) and sawtooth oscillations. The EC power can be switched between launchers on a time scale as needed by the immediate physics requirements. A revision of all injection angles of all launchers is under consideration for increased EC physics capabilities while relaxing the engineering constraints of both the EL and ULs. A series of design reviews are being planned with the five parties (EU, IN, JA, RF, US) procuring the EC system, the EC community and ITER Organization (IO). The review meetings qualify the design and provide an environment for enhancing performances while reducing costs, simplifying interfaces, predicting technology upgrades and commercial availability. In parallel, the test programs for critical components are being supported by IO and performed by the Domestic Agencies (DAs) for minimizing risks. The wide participation of the DAs provides a broad representation from the EC community, with the aim of collecting all expertise in guiding the EC system optimization. Still a strong relationship between IO and the DA is essential for optimizing the design of the EC system and for the installation and commissioning of all ex-vessel components when several
Suppression of the {Lambda}-{Sigma} coupling in nuclear matter
Bodmer, A.R.; Usmani, Q.N.
1995-08-01
We initiated a study of the modification of the coupling of the {Lambda}N to the {Sigma}N channel in nuclear matter with the Fermi hypernetted-chain variational approach. This modification of the {Lambda}N-{Sigma}N coupling is a central problem in hypernuclear physics and is related closely to the strongly repulsive three-body forces which are needed to account for hypernuclear binding energies. All earlier calculations have only considered this problem in the so-called G-matrix approximation which neglects important higher-order effects. An important result of this work will be a better understanding of the density dependence of {Lambda} binding in nuclear matter, which can then be tested in the calculation of the {Lambda} single-particle energies.
Iterated crowdsourcing dilemma game
NASA Astrophysics Data System (ADS)
Oishi, Koji; Cebrian, Manuel; Abeliuk, Andres; Masuda, Naoki
2014-02-01
The Internet has enabled the emergence of collective problem solving, also known as crowdsourcing, as a viable option for solving complex tasks. However, the openness of crowdsourcing presents a challenge because solutions obtained by it can be sabotaged, stolen, and manipulated at a low cost for the attacker. We extend a previously proposed crowdsourcing dilemma game to an iterated game to address this question. We enumerate pure evolutionarily stable strategies within the class of so-called reactive strategies, i.e., those depending on the last action of the opponent. Among the 4096 possible reactive strategies, we find 16 strategies each of which is stable in some parameter regions. Repeated encounters of the players can improve social welfare when the damage inflicted by an attack and the cost of attack are both small. Under the current framework, repeated interactions do not really ameliorate the crowdsourcing dilemma in a majority of the parameter space.
A high statistics measurement of the Lambda(+)(c) lifetime.
Link, J M; Reyes, M; Yager, P M; Anjos, J C; Bediaga, I; Göbel, C; Magnin, J; Massafferi, A; de Miranda, J M; Pepe, I M; dos Reis, A C; Carrillo, S; Casimiro, E; Cuautle, E; Sánchez-Hernández, A; Uribe, C; Vazquez, F; Agostino, L; Cinquini, L; Cumalat, J P; O'Reilly, B; Ramirez, J E; Segoni, I; Butler, J N; Cheung, H W K; Gaines, I; Garbincius, P H; Garren, L A; Gottschalk, E; Kasper, P H; Kreymer, A E; Kutschke, R; Bianco, S; Fabbri, F L; Zallo, A; Cawlfield, C; Kim, D Y; Rahimi, A; Wiss, J; Gardner, R; Kryemadhi, A; Chung, Y S; Kang, J S; Ko, B R; Kwak, J W; Lee, K B; Park, H; Alimonti, G; Boschini, M; D'Angelo, P; DiCorato, M; Dini, P; Giammarchi, M; Inzani, P; Leveraro, F; Malvezzi, S; Menasce, D; Mezzadri, M; Milazzo, L; Moroni, L; Pedrini, D; Pontoglio, C; Prelz, F; Rovere, M; Sala, S; Davenport, T F; Arena, V; Boca, G; Bonomi, G; Gianini, G; Liguori, G; Merlo, M M; Pantea, D; Ratti, S P; Riccardi, C; Vitulo, P; Hernandez, H; Lopez, A M; Luiggi, E; Mendez, H; Mendez, L; Mirles, A; Montiel, E; Olaya, D; Paris, A; Quinones, J; Rivera, C; Xiong, W; Zhang, Y; Wilson, J R; Cho, K; Handler, T; Mitchell, R; Engh, D; Hosack, M; Johns, W E; Nehring, M; Sheldon, P D; Stenson, K; Vaandering, E W; Webster, M; Sheaff, M
2002-04-22
A high statistics measurement of the Lambda(+)(c) lifetime from the Fermilab fixed-target FOCUS photoproduction experiment is presented. We describe the analysis technique with particular attention to the determination of the systematic uncertainty. The measured value of 204.6 +/- 3.4 (stat) +/- 2.5 (syst) fs from 8034 +/- 122 Lambda(+)(c)-->pK(-)pi(+) decays represents a significant improvement over the present world average. PMID:11955226
The chemical composition of three Lambda Bootis stars
Venn, K.A.; Lambert, D.L. )
1990-11-01
Abundance analyses are reported for three certain members (Lambda Boo, 29 Cyg, Pi1 Ori) of the class of rapidly rotating, metal-poor A-type stars known as Lambda Bootis stars. Model atmosphere analysis of high-resolution, high signal-to-noise spectra shows that the metal deficiencies are more severe than previously reported: Fe/H = -2.0, -1.8, -1.3 for Lambda Boo, 29 Cyg, and Pi1 Ori, respectively. Other metals (Mg, Ca, Ti, and Sr) are similarly underabundant, with Na often having a smaller underabundance. C, N, O, and S have near-solar abundances. Vega is shown to be a mild Lambda Boo star. The abundance anomalies of the Lambda Boo stars resemble those found for the interstellar gas in which the metals are depleted through formation of interstellar grains. It is suggested that the Lambda Boo stars are created when circumstellar (or interstellar) gas is separated from the grains and accreted by the star. The bulk of the interstellar grains comprises a circumstellar cloud or disk that is detectable by its infrared radiation. 67 refs.
Diagnostics of the ITER neutral beam test facility
Pasqualotto, R.; Serianni, G.; Agostini, M.; Brombin, M.; Dalla Palma, M.; Gazza, E.; Pomaro, N.; Rizzolo, A.; Spolaore, M.; Zaniol, B.; Sonato, P.; De Muri, M.; Croci, G.; Gorini, G.
2012-02-15
The ITER heating neutral beam (HNB) injector, based on negative ions accelerated at 1 MV, will be tested and optimized in the SPIDER source and MITICA full injector prototypes, using a set of diagnostics not available on the ITER HNB. The RF source, where the H{sup -}/D{sup -} production is enhanced by cesium evaporation, will be monitored with thermocouples, electrostatic probes, optical emission spectroscopy, cavity ring down, and laser absorption spectroscopy. The beam is analyzed by cooling water calorimetry, a short pulse instrumented calorimeter, beam emission spectroscopy, visible tomography, and neutron imaging. Design of the diagnostic systems is presented.
Diagnostics of the ITER neutral beam test facility.
Pasqualotto, R; Serianni, G; Sonato, P; Agostini, M; Brombin, M; Croci, G; Dalla Palma, M; De Muri, M; Gazza, E; Gorini, G; Pomaro, N; Rizzolo, A; Spolaore, M; Zaniol, B
2012-02-01
The ITER heating neutral beam (HNB) injector, based on negative ions accelerated at 1 MV, will be tested and optimized in the SPIDER source and MITICA full injector prototypes, using a set of diagnostics not available on the ITER HNB. The RF source, where the H(-)∕D(-) production is enhanced by cesium evaporation, will be monitored with thermocouples, electrostatic probes, optical emission spectroscopy, cavity ring down, and laser absorption spectroscopy. The beam is analyzed by cooling water calorimetry, a short pulse instrumented calorimeter, beam emission spectroscopy, visible tomography, and neutron imaging. Design of the diagnostic systems is presented.
Probing the Lambda-DGP Braneworld model
NASA Astrophysics Data System (ADS)
Ravanpak, Arvin; Farajollahi, Hossein; Fadakar, Golnaz
2016-09-01
We study cosmic dynamics in the context of the normal branch of the DGP braneworld model. Using current Planck data, we find the best fitting model and associated cosmological parameters in non-flat ΛDGP. With the transition redshift as a basic variable and statefinder parameters, our result shows that the Universe starts its accelerated expansion phase slightly earlier than expected in ΛCDM cosmology. The result also alleviates the coincidence problem of the ΛCDM model.
Alekseev, I. G.; Budkovsky, P. E.; Kanavets, V. P.; Kats, M. M.; Koroleva, L. I.; Kulikov, V. V.; Morozov, B. V.; Nesterov, V. M.; Ryltsov, V. V.; Sakharov, V. A.; Sulimov, A. D.; Svirida, D. N.; Filimonov, E. A.; Golubev, V. V.; Kovalev, A. I.; Kozlenko, N. G.; Kozlov, V. S.; Krivshich, A. G.; Novinsky, D. V.; Sumachev, V. V.
2007-06-13
The idea of 'EPECUR' was inspired by the recent splash of the activity around the pentaquark matters. The goal of the experiment is the search for narrow resonant states in the reactions {pi}-p {yields} {pi}-p and {pi}-p {yields} K0{lambda} based on the very precise cross section measurements in fine energy steps of 0.5 MeV in terms of the invariant mass. As a valuable byproduct of the second stage of the experiment, {lambda}-polarization in {pi}-p {yields} K0{lambda} can be measured, based on the well-known weak {lambda}-decay asymmetry. The expected statistical significance of the measurement overrides the best existing data from 'NIMROD' detector by an order of magnitude. The experimental setup is under construction at the ITEP proton synchrotron in collaboration with PNPI and ACU.
Can Accelerators Accelerate Learning?
NASA Astrophysics Data System (ADS)
Santos, A. C. F.; Fonseca, P.; Coelho, L. F. S.
2009-03-01
The 'Young Talented' education program developed by the Brazilian State Funding Agency (FAPERJ) [1] makes it possible for high-schools students from public high schools to perform activities in scientific laboratories. In the Atomic and Molecular Physics Laboratory at Federal University of Rio de Janeiro (UFRJ), the students are confronted with modern research tools like the 1.7 MV ion accelerator. Being a user-friendly machine, the accelerator is easily manageable by the students, who can perform simple hands-on activities, stimulating interest in physics, and getting the students close to modern laboratory techniques.
Can Accelerators Accelerate Learning?
Santos, A. C. F.; Fonseca, P.; Coelho, L. F. S.
2009-03-10
The 'Young Talented' education program developed by the Brazilian State Funding Agency (FAPERJ)[1] makes it possible for high-schools students from public high schools to perform activities in scientific laboratories. In the Atomic and Molecular Physics Laboratory at Federal University of Rio de Janeiro (UFRJ), the students are confronted with modern research tools like the 1.7 MV ion accelerator. Being a user-friendly machine, the accelerator is easily manageable by the students, who can perform simple hands-on activities, stimulating interest in physics, and getting the students close to modern laboratory techniques.
Expression of immunoglobulin kappa and lambda chains in mink.
Bovkun, L A; Peremislov, V V; Nayakshin, A M; Belousov, E S; Mechetina, L V; Aasted, B; Taranin, A V
1993-08-01
The ratio of kappa and lambda chains of immunoglobulins varies significantly from one species to another. It has previously been thought that lambda was only type expressed in mink. We tested mink immunoglobulin light chains using two monoclonal antibodies G80 and G88. It has been shown that G80 and G88 specifically recognize two antigenically different subpopulations of the light chains. Immunochemical analysis of these subpopulations separated by affinity chromatography suggested that they represent lambda and kappa types of light chains, respectively. Screening of a mink cDNA library with monoclonal antibody G88 resulted in the isolation of clone pIGK-1 containing kappa chain-encoding sequence. The cDNA insert of pIGK-1 included most of the V segment, as well as the J, C and 3' untranslated sequences. Mink V kappa sequence shown the highest homology with the human V kappa II subgroup genes (76-79%). Mink C kappa sequence was 53-63% homologous to C kappa of other species. The striking feature of mink C kappa chain is the presence of glutamine in the C-terminal position. Southern blot analysis suggested that mink haploid genome has one C kappa gene and multiple V kappa genes. The kappa:lambda chain ratio in the 12 minks studied was, on the average, 46:54. The same ratio was observed for the kappa- and lambda-producing cells in the mesenteric lymph nodes. The five previously identified mink light chain allotypes were assigned to the lambda chains, thereby confirming that lambda chains in this species are additionally subdivided into several subtypes.
Ultraviolet Synthetic Spectra for Three Lambda Bootis Stars
NASA Astrophysics Data System (ADS)
Cheng, Kwang-Ping; Neff, James E.; Gray, Richard O.; Corbally, Christopher J.; Johnson, Dustin; Tarbell, Erik
2015-01-01
Lambda Boo-type stars are a group of late B to early F-type Population I dwarfs that show mild to extreme deficiencies of iron-peak elements (up to 2 dex), but their C, N, O, and S abundances are near solar. We show that the International Ultraviolet Explorer (IUE) spectra (1280-3200 A) of Lambda Bootis, 29 Cygni (a "confirmed" Lambda Boo star), and Vega (a "mild" Lambda Boo star) can be fit remarkably well by single-temperature synthetic spectra. We computed the full resolution synthetic ultraviolet (UV) spectrum covering the IUE wavelength range using Gray's Stellar Spectral Synthesis Program SPECTRUM. To improve the synthetic spectra, we generated a grid of LTE atmosphere models with the appropriate stellar parameters using ATLAS9 and the existing Castelli and Kurucz 2004 models. One of the improvements of their opacity distribution functions (ODFs) is the addition to the line blanketing near 1400 A and 1600 A by the quasi-molecular absorptions of atomic hydrogen undergoing collisions with protons and other neutral hydrogen atoms. New-ODF fluxes reproduce the ultraviolet observations of Lambda Boo stars in a more realistic way than previous computations. We also constructed our own UV line list for the relevant set of absorption features. Modeling the UV line spectra of Lambda Boo stars allows us to confirm their published surface abundances, including CNO and the iron group elements. It also provides further insight into their photospheric conditions (e.g., Teff, log g, [M/H], micro turbulent velocity, etc.). About 40 percent of the published Lambda Boo candidates have existing IUE spectra. We plan to follow this pilot study and perform UV spectral synthesis for all of them.
Electron capture acceleration channel in a slit laser beam
Wang, P. X.; Scheid, W.; Ho, Y. K.
2007-03-12
Using numerical simulations, the authors find that the electrons can be captured and accelerated to high energies (GeV) in a slit laser beam with an intensity of I{lambda}{sup 2}{approx}10{sup 20} W/cm{sup 2} {mu}m{sup 2}, where {lambda} is the laser wavelength in units of {mu}m. The range of the optimum incident energy is very wide, even up to GeV. These results are of interest for experiments because the relatively low intensity can be achieved with present chirped pulse amplification technique and a wide range of incident energies means that a multistage acceleration is possible.
Xu Qinghua
2007-06-13
This contribution reports on a proof-of-principle measurement of the longitudinal spin transfer DLL in inclusive {lambda} and {lambda}-bar production in polarized proton-proton collisions at a center of mass energy {radical}(s) = 200 GeV. The data sample consists of about 3 x 106 minimum bias events collected in the year 2005 by the STAR experiment at RHIC with proton beam polarizations of up to 50%. The {lambda}({lambda}-bar) candidates are reconstructed at mid-rapidity (|{eta}| < 1) using the STAR Time Projection Chamber via the dominant decay channel {lambda} {yields} p{pi}- ({lambda}-bar {yields} p-bar{pi}+). Their mean transverse momentum pT is about 1.3 GeV/c and longitudinal momentum fraction xF = 7.5 x 10-3. The longitudinal {lambda}({lambda}-bar) polarization is determined using a method in which the detector acceptance mostly cancels.
G. Douglas Loesser, et. al.
2012-09-21
The ITER Diagnostic Division is responsible for designing and procuring the First Wall Blankets that are mounted on the vacuum vessel port plugs at both the upper and equatorial levels This paper will discuss the effects of the diagnostic aperture shape and configuration on the coolant circuit design. The DFW design is driven in large part by the need to conform the coolant arrangement to a wide variety of diagnostic apertures combined with the more severe heating conditions at the surface facing the plasma, the first wall. At the first wall, a radiant heat flux of 35W/cm2 combines with approximate peak volumetric heating rates of 8W/cm3 (equatorial ports) and 5W/cm3 (upper ports). Here at the FW, a fast thermal response is desirable and leads to a thin element between the heat flux and coolant. This requirement is opposed by the wish for a thicker FW element to accommodate surface erosion and other off-normal plasma events.
NASA Astrophysics Data System (ADS)
Jaeger, E. F.; Berry, L. A.; Myra, J. R.
2006-10-01
Fast magnetosonic waves in the ion cyclotron range of frequencies (ICRF) can convert to much shorter wavelength modes such as ion Bernstein waves (IBW) and ion cyclotron waves (ICW) [1]. These modes are potentially useful for plasma control through the generation of localized currents and sheared flows. As part of the SciDAC Center for Simulation of Wave-Plasma Interactions project, the AORSA global-wave solver [2] has been ported to the new, dual-core Cray XT-3 (Jaguar) at ORNL where it demonstrates excellent scaling with the number of processors. Preliminary calculations using 4096 processors have allowed the first full-wave simulations of mode conversion in ITER. Mode conversion from the fast wave to the ICW is observed in mixtures of deuterium, tritium and helium3 at 53 MHz. The resulting flow velocity and electric field shear will be calculated. [1] F.W. Perkins, Nucl. Fusion 17, 1197 (1977). [2] E.F. Jaeger, L.A. Berry, J.R. Myra, et al., Phys. Rev. Lett. 90, 195001-1 (2003).
Iterative retrieval of surface emissivity and temperature for a hyperspectral sensor
Borel, C.C.
1997-11-01
The central problem of temperature-emissivity separation is that we obtain N spectral measurements of radiance and need to find N + 1 unknowns (N emissivities and one temperature). To solve this problem in the presence of the atmosphere we need to find even more unknowns: N spectral transmissions {tau}{sub atmo}({lambda}) up-welling path radiances L{sub path}{up_arrow}({lambda}) and N down-welling path radiances L{sub path}{down_arrow}({lambda}). Fortunately there are radiative transfer codes such as MODTRAN 3 and FASCODE available to get good estimates of {tau}{sub atmo}({lambda}), L{sub path}{up_arrow}({lambda}) and L{sub path}{down_arrow}({lambda}) in the order of a few percent. With the growing use of hyperspectral imagers, e.g. AVIRIS in the visible and short-wave infrared there is hope of using such instruments in the mid-wave and thermal IR (TIR) some day. We believe that this will enable us to get around using the present temperature - emissivity separation (TES) algorithms using methods which take advantage of the many channels available in hyperspectral imagers. The first idea we had is to take advantage of the simple fact that a typical surface emissivity spectrum is rather smooth compared to spectral features introduced by the atmosphere. Thus iterative solution techniques can be devised which retrieve emissivity spectra {epsilon} based on spectral smoothness. To make the emissivities realistic, atmospheric parameters are varied using approximations, look-up tables derived from a radiative transfer code and spectral libraries. By varying the surface temperature over a small range a series of emissivity spectra are calculated. The one with the smoothest characteristic is chosen. The algorithm was tested on synthetic data using MODTRAN and the Salisbury emissivity database.
Aaltonen, T.; Alvarez Gonzalez, B.; Amerio, S.; Amidei, D.; Anastassov, A.; Annovi, A.; Antos, J.; Apollinari, G.; Appel, J.A.; Arisawa, T.; Artikov, A.; /Dubna, JINR /Texas A-M
2011-12-01
We report an analysis of the {Lambda}{sub b}{sup 0} {yields} {Lambda}{sub c}{sup +}{pi}{sup -}{pi}{sup +}{pi}{sup -} decay in a data sample collected by the CDF II detector at the Fermilab Tevatron corresponding to 2.4 fb{sup -1} of integrated luminosity. We reconstruct the currently largest samples of the decay modes {Lambda}{sub b}{sup 0} {yields} {Lambda}{sub c}(2595){sup +}{pi}{sup -} (with {Lambda}{sub c}(2595){sup +} {yields} {Lambda}{sub c}{sup +}{pi}{sup +}{pi}{sup -}), {Lambda}{sub b}{sup 0} {yields} {Lambda}{sub c}(2625){sup +}{pi}{sup -} (with {Lambda}{sub c}(2625){sup +} {yields} {Lambda}{sub c}{sup +}{pi}{sup +}{pi}{sup -}), {Lambda}{sub b}{sup 0} {yields} {Sigma}{sub c}(2455){sup ++}{pi}{sup -}{pi}{sup -} (with {Sigma}{sub c}(2455){sup ++} {yields} {Lambda}{sub c}{sup +}{pi}{sup +}), and {Lambda}{sub b}{sup 0} {yields} {Sigma}{sub c}(2455)0{pi}{sup +}{pi}{sup -} (with {Sigma}{sub c}(2455)0 {yields} {Lambda}{sub c}{sup +}{pi}{sup -}) and measure the branching fractions relative to the {Lambda}{sub b}{sup 0} {yields} {Lambda}{sub c}{sup +}{pi}{sup -} branching fraction. We measure the ratio {Beta}({Lambda}{sub b}{sup 0} {yields} {Lambda}{sub c}{sup +}{pi}{sup -}{pi}{sup +}{pi}{sup -})/ {Beta}({Lambda}{sub b}{sup 0} {yields} {Lambda}{sub c}{sup +}{pi}{sup -})=3.04 {+-} 0.33(stat){sub -0.55}{sup +0.70}(syst) which is used to derive {Beta}({Lambda}{sub b}{sup 0} {yields} {Lambda}{sub c}{sup +}{pi}{sup -}{pi}{sup +}{pi}{sup -})=(26.8{sub -11.2}{sup +11.9}) x 10{sup -3}.
Space Charge Neutralization in the ITER Negative Ion Beams
Surrey, Elizabeth
2007-08-10
A model of the space charge neutralization of negative ion beams, developed from the model due to Holmes, is applied to the ITER heating and diagnostic beams. The Holmes model assumed that the plasma electron temperature was derived from the stripped electrons. This is shown to be incorrect for the ITER beams and the plasma electron temperature is obtained from the average creation energy upon ionization. The model shows that both ITER beams will be fully space charge compensated in the drift distance between the accelerator and the neutralizer. Inside the neutralizer, the plasma over compensates the space charge to the extent that a significant focusing force is predicted. At a certain position in the neutraliser this force balances the defocusing force due to the ions' transverse energy. Under these conditions the beam distribution function can change from Gaussian to Bennett and evidence of such a distribution observed in a multi-aperture, neutralized negative ion beam is presented.
Gamma ray spectrometer for ITER
Gin, D.; Chugunov, I.; Shevelev, A.; Khilkevitch, E.; Doinikov, D.; Naidenov, V.; Pasternak, A.; Polunovsky, I.; Kiptily, V.
2014-08-21
Gamma diagnostics is considered to be primary for the confined α-particles and runaway electrons measurements on ITER. The gamma spectrometer will be embedded into a neutron dump of the ITER Neutral Particle Analyzer diagnostic complex. It will supplement NPA measurements on the fuel isotope ratio and confined alphas/fast ions. In this paper an update on ITER gamma spectrometer developments is given. A new geometry of the system is described and detailed analysis of expected signals for the spectrometer is presented.
Tang, Wei; Hicks, Kenneth. H.; Keller, Dustin M.; Kim, S.-H.; Kim, H.-C.
2013-06-01
The first high-statistics cross sections for the reactions $\\gamma p \\to K^{*+} \\Lambda$ and $\\gamma p \\to K^{*+} \\Sigma^0$ were measured using the CLAS detector at photon energies between threshold and 3.9 GeV at the Thomas Jefferson National Accelerator Facility. Differential cross sections are presented over the full range of the center-of-mass angles, $\\theta^{CM}_{K^{*+}}$, and then fitted to Legendre polynomials to extract the total cross section. Results for the $K^{*+}\\Lambda$ final state are compared with two different calculations in an isobar and a Regge model, respectively. Theoretical calculations significantly underestimate the $K^{*+} \\Lambda$ total cross sections between 2.1 and 2.6 GeV, but are in better agreement with present data at higher photon energies.
Azzurri, P.; Barria, P.; Ciocci, M.A.; Donati, S.; Vataga, E.
2009-12-01
The authors present the first observation of the {Lambda}{sub b}{sup 0} {yields} {Lambda}{sub c}{sup +}{pi}{sup -}{pi}{sup +}{pi}{sup -} decay using data from an integrated luminosity of approximately 2.4 fb{sup -1} of p{bar p} collisions at {radical}s = 1.96 TeV, collected with the CDF II detector at the Fermilab Tevatron. They also present the first observation of the resonant decays {Lambda}{sub b}{sup 0} {yields} {Sigma}{sub c}(2455){sup 0} {pi}{sup +}{pi}{sup -} {yields} {Lambda}{sub c}{sup +}{pi}{sup -}{pi}{sup +}{pi}{sup -}, {Lambda}{sub b}{sup 0} {yields} {Sigma}{sub c}(2455){sup ++}{pi}{sup -}{pi}{sup -} {yields} {Lambda}{sub c}{sup +}{pi}{sup -}{pi}{sup +}{pi}{sup -}, {Lambda}{sub b}{sup 0} {yields} {Lambda}{sub c}(2595){sup +}{pi}{sup -} {yields} {Lambda}{sub c}{sup +}{pi}{sup -}{pi}{sup +}{pi}{sup -} and {Lambda}{sub b}{sup 0} {yields} {Lambda}{sub c}(2625){sup +}{pi}{sup -} {yields} {Lambda}{sub c}{sup +}{pi}{sup -}{pi}{sup +}{pi}{sup -}, and measure their relative branching ratios.
Iterative methods for symmetric ill-conditioned Toeplitz matrices
Huckle, T.
1996-12-31
We consider ill-conditioned symmetric positive definite, Toeplitz systems T{sub n}x = b. If we want to solve such a system iteratively with the conjugate gradient method, we can use band-Toeplitz-preconditioners or Sine-Transform-peconditioners M = S{sub n}{Lambda}S{sub n}, S{sub n} the Sine-Transform-matrix and {Lambda} a diagonal matrix. A Toeplitz matrix T{sub n} = (t{sub i-j)}{sub i}{sup n},{sub j=1} is often related to an underlying function f defined by the coefficients t{sub j}, j = -{infinity},..,-1,0, 1,.., {infinity}. There are four cases, for which we want to determine a preconditioner M: - T{sub n} is related to an underlying function which is given explicitly; - T{sub n} is related to an underlying function that is given by its Fourier coefficients; - T{sub n} is related to an underlying function that is unknown; - T{sub n} is not related to an underlying function. Especially for the first three cases we show how positive definite and effective preconditioners based on the Sine-Transform can be defined for general nonnegative underlying function f. To define M, we evaluate or estimate the values of f at certain positions, and build a Sine-transform matrix with these values as eigenvalues. Then, the spectrum of the preconditioned system is bounded from above and away from zero.
A Measurement of the Recoil Polarization of Electroproduced {Lambda}(1116)
Simeon McAleer
2002-01-01
The CEBAF Large Acceptance Spectrometer at the Thomas Jefferson National Laboratory was used to study the reaction e + p {yields} e{prime} + K{sup +} + {Lambda}(1116) for events where {Lambda}(1116) subsequently decayed via the channel {Lambda}(1116) {yields} p + {pi}{sup -}. Data were taken at incident electron beam energies of 2.5, 4.0, and 4.2 GeV during the 1999 E1C run period. They hyperon production spectra span the Q{sup 2} range from 0.5 to 2.8 GeV{sup 2} and nearly the entire range in the center of mass angles. The proton angular distribution in the {Lambda}(1116) rest frame is used to deduce the recoil polarization of the hyperon, and the W and cos {theta}{sub cm}{sup K+} dependence of the recoil polarization will be presented. The data show sizeable negative polarizations for the {Lambda}(1116) as a function of both cos {theta}{sub cm}{sup K+} and W.
Channeled spectropolarimetry using iterative reconstruction
NASA Astrophysics Data System (ADS)
Lee, Dennis J.; LaCasse, Charles F.; Craven, Julia M.
2016-05-01
Channeled spectropolarimeters (CSP) measure the polarization state of light as a function of wavelength. Conventional Fourier reconstruction suffers from noise, assumes the channels are band-limited, and requires uniformly spaced samples. To address these problems, we propose an iterative reconstruction algorithm. We develop a mathematical model of CSP measurements and minimize a cost function based on this model. We simulate a measured spectrum using example Stokes parameters, from which we compare conventional Fourier reconstruction and iterative reconstruction. Importantly, our iterative approach can reconstruct signals that contain more bandwidth, an advancement over Fourier reconstruction. Our results also show that iterative reconstruction mitigates noise effects, processes non-uniformly spaced samples without interpolation, and more faithfully recovers the ground truth Stokes parameters. This work offers a significant improvement to Fourier reconstruction for channeled spectropolarimetry.
Prediction of narrow N* and {Lambda}* with hidden charm
Wu Jiajun; Molina, R.; Oset, E.; Zou, B. S.
2011-10-24
The interaction between various charmed mesons and charmed baryons, such as D-bar{Sigma}{sub c}-D-bar{Lambda}{sub c}, D-bar*{Sigma}{sub c}-D-bar*{Lambda}{sub c}, and related strangeness channels, are studied within the framework of the coupled channel unitary approach with the local hidden gauge formalism. Six narrow N* and {Lambda}* resonances are dynamically generated with mass above 4 GeV and width smaller than 100 MeV. These predicted new resonances definitely cannot be accommodated by quark models with three constituent quarks. We make estimates of production cross sections of these predicted resonances in p-barp collisions for PANDA at the forthcoming FAIR facility.
Characterization of a lymphoblastoid line deleted for lambda immunoglobulin genes
Hough, C.A., White, B.N., Holden, J.A.
1995-04-01
While characterizing the cat eye syndrome (CES) supernumerary chromosome for the presence of {lambda} immunoglobulin gene region sequences, a lymphoblastoid cell line from one CES patient was identified in which there was selection of cells deleted from some IGLC and IGLV genes. Two distinct deletions, one on each chromosome 22, were identified, presumably arising from independent somatic recombination events occurring during B-lymphocyte differentiation. The extent of the deleted regions was determined using probes from the various IGLV subgroups and they each covered at least 82 kilobases. The precise definition of the deletions was not possible because of conservation of some restriction sites in the IGLV region. The cell line was used to map putative IGLV genes within the recombinant phage {lambda}V{lambda}135 to the distal part of the IGLV gene region. 35 refs., 4 figs.
Observation of B{sup +}{yields}p{lambda}{gamma}
Lee, Y.-J.; Wang, M.-Z.; Chang, M.-C.; Chang, P.; Chao, Y.; Chen, K.-F.; Hou, W.-S.; Hsiung, Y. B.; Lin, S.-W.; Schuemann, J.; Ueno, K.; Wang, C.C.; Abe, K.; Gershon, T.; Haba, J.; Hazumi, M.; Ishikawa, A.; Itoh, R.; Iwasaki, Y.; Katayama, N.
2005-08-05
We report the first observation of the radiative hyperonic B decay B{sup +}{yields}p{lambda}{gamma}, using a 140 fb{sup -1} data sample recorded on the {upsilon}(4S) resonance with the Belle detector at the KEKB asymmetric energy e{sup +}e{sup -} collider. The measured branching fraction is B(B{sup +}{yields}p{lambda}{gamma})=(2.16{sub -0.53}{sup +0.58}{+-}0.20)x10{sup -6}. We examine its M{sub p{lambda}} distribution and observe a peak near threshold. This feature is expected by the short-distance b{yields}s{gamma} transition. A search for B{sup +}{yields}p{sigma}{sup 0}{gamma} yields no significant signal, and we set a 90% confidence-level upper limit on the branching fraction of B(B{sup +}{yields}p{sigma}{sup 0}{gamma})<4.6x10{sup -6}.
Majling, L. Gmuca, S.
2007-09-15
At the LHE JINR, an original approach to hypernuclear experiments was elaborated to produce relativistic hypernuclei. The production cross sections and lifetimes, {tau}, of {sub {lambda}}{sup 3}H and {sub {lambda}}{sup 4}H were measured successfully. The results of recent experiments on {sup 5}H and {sup 7}H nuclei suggest that the hypernucleus {sub {lambda}}{sup 6}H might be stable and that this may be the case even for {sub {lambda}}{sup 8}H. The unique quality of the spectrometer SPHERE may be used to identify unambiguously the isotopes of hyperhydrogen-through their pionic decay {sub {lambda}}{sup A}H {sup {yields}} {pi}{sup -} + {sup A}He-including the new hypernuclei {sub {lambda}}{sup 6}H and {sub {lambda}}{sup 8}H with extreme values of N/Z of 4 and 6, respectively. The confirmation of the very existence of these neutron-rich hypernuclei would be a strong motivation to search for their spectra in strangeness and double-charge-exchange reactions (K{sub stop}{sup -}, {pi}{sup +}) at FINUDA or ({pi}{sup -}, K{sup +}) at J-PARC. It is very probable that, similarly as in {sub {lambda}}{sup 4}H, there is a low-lying state 1{sup +} also in {sub {lambda}}{sup 6}H and {sub {lambda}}{sup 8}H. If their electromagnetic width (M1) is small enough, we could see two different values of {tau} for {sub {lambda}}{sup 6}H and/or {sub {lambda}}{sup 8}H. We investigate the spacings of the 1{sup +} and 0{sup +} states of {sub {lambda}}{sup 4}H, {sub {lambda}}{sup 6}H, and {sub {lambda}}{sup 8}H. The understanding of the structure of isospin asymmetric systems plays a key role in the description of systems as diverse as neutron-rich nuclei and neutron matter.
Adaptive self-calibrating iterative GRAPPA reconstruction.
Park, Suhyung; Park, Jaeseok
2012-06-01
Parallel magnetic resonance imaging in k-space such as generalized auto-calibrating partially parallel acquisition exploits spatial correlation among neighboring signals over multiple coils in calibration to estimate missing signals in reconstruction. It is often challenging to achieve accurate calibration information due to data corruption with noises and spatially varying correlation. The purpose of this work is to address these problems simultaneously by developing a new, adaptive iterative generalized auto-calibrating partially parallel acquisition with dynamic self-calibration. With increasing iterations, under a framework of the Kalman filter spatial correlation is estimated dynamically updating calibration signals in a measurement model and using fixed-point state transition in a process model while missing signals outside the step-varying calibration region are reconstructed, leading to adaptive self-calibration and reconstruction. Noise statistic is incorporated in the Kalman filter models, yielding coil-weighted de-noising in reconstruction. Numerical and in vivo studies are performed, demonstrating that the proposed method yields highly accurate calibration and thus reduces artifacts and noises even at high acceleration. PMID:21994010
Adaptive self-calibrating iterative GRAPPA reconstruction.
Park, Suhyung; Park, Jaeseok
2012-06-01
Parallel magnetic resonance imaging in k-space such as generalized auto-calibrating partially parallel acquisition exploits spatial correlation among neighboring signals over multiple coils in calibration to estimate missing signals in reconstruction. It is often challenging to achieve accurate calibration information due to data corruption with noises and spatially varying correlation. The purpose of this work is to address these problems simultaneously by developing a new, adaptive iterative generalized auto-calibrating partially parallel acquisition with dynamic self-calibration. With increasing iterations, under a framework of the Kalman filter spatial correlation is estimated dynamically updating calibration signals in a measurement model and using fixed-point state transition in a process model while missing signals outside the step-varying calibration region are reconstructed, leading to adaptive self-calibration and reconstruction. Noise statistic is incorporated in the Kalman filter models, yielding coil-weighted de-noising in reconstruction. Numerical and in vivo studies are performed, demonstrating that the proposed method yields highly accurate calibration and thus reduces artifacts and noises even at high acceleration.
A unified evaluation of iterative projection algorithms for phase retrieval
Marchesini, S
2006-03-08
Iterative projection algorithms are successfully being used as a substitute of lenses to recombine, numerically rather than optically, light scattered by illuminated objects. Images obtained computationally allow aberration-free diffraction-limited imaging and allow new types of imaging using radiation for which no lenses exist. The challenge of this imaging technique is transferred from the lenses to the algorithms. We evaluate these new computational ''instruments'' developed for the phase retrieval problem, and discuss acceleration strategies.
Adcox, K; Adler, S S; Ajitanand, N N; Akiba, Y; Alexander, J; Aphecetche, L; Arai, Y; Aronson, S H; Averbeck, R; Awes, T C; Barish, K N; Barnes, P D; Barrette, J; Bassalleck, B; Bathe, S; Baublis, V; Bazilevsky, A; Belikov, S; Bellaiche, F G; Belyaev, S T; Bennett, M J; Berdnikov, Y; Botelho, S; Brooks, M L; Brown, D S; Bruner, N; Bucher, D; Buesching, H; Bumazhnov, V; Bunce, G; Burward-Hoy, J; Butsyk, S; Carey, T A; Chand, P; Chang, J; Chang, W C; Chavez, L L; Chernichenko, S; Chi, C Y; Chiba, J; Chiu, M; Choudhury, R K; Christ, T; Chujo, T; Chung, M S; Chung, P; Cianciolo, V; Cole, B A; D'Enterria, D G; David, G; Delagrange, H; Denisov, A; Deshpande, A; Desmond, E J; Dietzsch, O; Dinesh, B V; Drees, A; Durum, A; Dutta, D; Ebisu, K; Efremenko, Y V; el-Chenawi, K; En'yo, H; Esumi, S; Ewell, L; Ferdousi, T; Fields, D E; Fokin, S L; Fraenkel, Z; Franz, A; Frawley, A D; Fung, S-Y; Garpman, S; Ghosh, T K; Glenn, A; Godoi, A L; Goto, Y; Greene, S V; Grosse Perdekamp, M; Gupta, S K; Guryn, W; Gustafsson, H-A; Haggerty, J S; Hamagaki, H; Hansen, A G; Hara, H; Hartouni, E P; Hayano, R; Hayashi, N; He, X; Hemmick, T K; Heuser, J M; Hibino, M; Hill, J C; Ho, D S; Homma, K; Hong, B; Hoover, A; Ichihara, T; Imai, K; Ippolitov, M S; Ishihara, M; Jacak, B V; Jang, W Y; Jia, J; Johnson, B M; Johnson, S C; Joo, K S; Kametani, S; Kang, J H; Kann, M; Kapoor, S S; Kelly, S; Khachaturov, B; Khanzadeev, A; Kikuchi, J; Kim, D J; Kim, H J; Kim, S Y; Kim, Y G; Kinnison, W W; Kistenev, E; Kiyomichi, A; Klein-Boesing, C; Klinksiek, S; Kochenda, L; Kochetkov, V; Koehler, D; Kohama, T; Kotchetkov, D; Kozlov, A; Kroon, P J; Kurita, K; Kweon, M J; Kwon, Y; Kyle, G S; Lacey, R; Lajoie, J G; Lauret, J; Lebedev, A; Lee, D M; Leitch, M J; Li, X H; Li, Z; Lim, D J; Liu, M X; Liu, X; Liu, Z; Maguire, C F; Mahon, J; Makdisi, Y I; Manko, V I; Mao, Y; Mark, S K; Markacs, S; Martinez, G; Marx, M D; Masaike, A; Matathias, F; Matsumoto, T; McGaughey, P L; Melnikov, E; Merschmeyer, M; Messer, F; Messer, M; Miake, Y; Miller, T E; Milov, A; Mioduszewski, S; Mischke, R E; Mishra, G C; Mitchell, J T; Mohanty, A K; Morrison, D P; Moss, J M; Mühlbacher, F; Mukhopadhyay, D; Muniruzzaman, M; Murata, J; Nagamiya, S; Nagasaka, Y; Nagle, J L; Nakada, Y; Nandi, B K; Newby, J; Nikkinen, L; Nilsson, P; Nishimura, S; Nyanin, A S; Nystrand, J; O'Brien, E; Ogilvie, C A; Ohnishi, H; Ojha, I D; Ono, M; Onuchin, V; Oskarsson, A; Osterman, L; Otterlund, I; Oyama, K; Paffrath, L; Pal, D; Palounek, A P T; Pantuev, V S; Papavassiliou, V; Pate, S F; Peitzmann, T; Petridis, A N; Pinkenburg, C; Pisani, R P; Pitukhin, P; Plasil, F; Pollack, M; Pope, K; Purschke, M L; Ravinovich, I; Read, K F; Reygers, K; Riabov, V; Riabov, Y; Rosati, M; Rose, A A; Ryu, S S; Saito, N; Sakaguchi, A; Sakaguchi, T; Sako, H; Sakuma, T; Samsonov, V; Sangster, T C; Santo, R; Sato, H D; Sato, S; Sawada, S; Schlei, B R; Schutz, Y; Semenov, V; Seto, R; Shea, T K; Shein, I; Shibata, T-A; Shigaki, K; Shiina, T; Shin, Y H; Sibiriak, I G; Silvermyr, D; Sim, K S; Simon-Gillo, J; Singh, C P; Singh, V; Sivertz, M; Soldatov, A; Soltz, R A; Sorensen, S; Stankus, P W; Starinsky, N; Steinberg, P; Stenlund, E; Ster, A; Stoll, S P; Sugioka, M; Sugitate, T; Sullivan, J P; Sumi, Y; Sun, Z; Suzuki, M; Takagui, E M; Taketani, A; Tamai, M; Tanaka, K H; Tanaka, Y; Taniguchi, E; Tannenbaum, M J; Thomas, J; Thomas, J H; Thomas, T L; Tian, W; Tojo, J; Torii, H; Towell, R S; Tserruya, I; Tsuruoka, H; Tsvetkov, A A; Tuli, S K; Tydesjö, H; Tyurin, N; Ushiroda, T; Van Hecke, H W; Velissaris, C; Velkovska, J; Velkovsky, M; Vinogradov, A A; Volkov, M A; Vorobyov, A; Vznuzdaev, E; Wang, H; Watanabe, Y; White, S N; Witzig, C; Wohn, F K; Woody, C L; Xie, W; Yagi, K; Yokkaichi, S; Young, G R; Yushmanov, I E; Zajc, W A; Zhang, Z; Zhou, S; Zhou, S
2002-08-26
We present results on the measurement of Lambda and Lambda(macro) production in Au+Au collisions at square root of (S (NN) = 130 GeV with the PHENIX detector at the Relativistic Heavy Ion Collider. The transverse momentum spectra were measured for minimum bias and for the 5% most central events. The Lambda;/Lambda ratios are constant as a function of p(T) and the number of participants. The measured net Lambda density is significantly larger than predicted by models based on hadronic strings (e.g., HIJING) but in approximate agreement with models which include the gluon-junction mechanism.
Adler, C; Ahammed, Z; Allgower, C; Amonett, J; Anderson, B D; Anderson, M; Averichev, G S; Balewski, J; Barannikova, O; Barnby, L S; Baudot, J; Bekele, S; Belaga, V V; Bellwied, R; Berger, J; Bichsel, H; Billmeier, A; Bland, L C; Blyth, C O; Bonner, B E; Boucham, A; Brandin, A; Bravar, A; Cadman, R V; Caines, H; Calderón de la Barca Sánchez, M; Cardenas, A; Carroll, J; Castillo, J; Castro, M; Cebra, D; Chaloupka, P; Chattopadhyay, S; Chen, Y; Chernenko, S P; Cherney, M; Chikanian, A; Choi, B; Christie, W; Coffin, J P; Cormier, T M; Cramer, J G; Crawford, H J; Deng, W S; Derevschikov, A A; Didenko, L; Dietel, T; Draper, J E; Dunin, V B; Dunlop, J C; Eckardt, V; Efimov, L G; Emelianov, V; Engelage, J; Eppley, G; Erazmus, B; Fachini, P; Faine, V; Faivre, J; Filimonov, K; Finch, E; Fisyak, Y; Flierl, D; Foley, K J; Fu, J; Gagliardi, C A; Gagunashvili, N; Gans, J; Gaudichet, L; Germain, M; Geurts, F; Ghazikhanian, V; Grachov, O; Grigoriev, V; Guedon, M; Gushin, E; Hallman, T J; Hardtke, D; Harris, J W; Henry, T W; Heppelmann, S; Herston, T; Hippolyte, B; Hirsch, A; Hjort, E; Hoffmann, G W; Horsley, M; Huang, H Z; Humanic, T J; Igo, G; Ishihara, A; Ivanshin, Yu I; Jacobs, P; Jacobs, W W; Janik, M; Johnson, I; Jones, P G; Judd, E G; Kaneta, M; Kaplan, M; Keane, D; Kiryluk, J; Kisiel, A; Klay, J; Klein, S R; Klyachko, A; Konstantinov, A S; Kopytine, M; Kotchenda, L; Kovalenko, A D; Kramer, M; Kravtsov, P; Krueger, K; Kuhn, C; Kulikov, A I; Kunde, G J; Kunz, C L; Kutuev, R Kh; Kuznetsov, A A; Lakehal-Ayat, L; Lamont, M A C; Landgraf, J M; Lange, S; Lansdell, C P; Lasiuk, B; Laue, F; Lauret, J; Lebedev, A; Lednický, R; Leontiev, V M; LeVine, M J; Li, Q; Lindenbaum, S J; Lisa, M A; Liu, F; Liu, L; Liu, Z; Liu, Q J; Ljubicic, T; Llope, W J; LoCurto, G; Long, H; Longacre, R S; Lopez-Noriega, M; Love, W A; Ludlam, T; Lynn, D; Ma, J; Majka, R; Margetis, S; Markert, C; Martin, L; Marx, J; Matis, H S; Matulenko, Yu A; McShane, T S; Meissner, F; Melnick, Yu; Meschanin, A; Messer, M; Miller, M L; Milosevich, Z; Minaev, N G; Mitchell, J; Moiseenko, V A; Moore, C F; Morozov, V; de Moura, M M; Munhoz, M G; Nelson, J M; Nevski, P; Nikitin, V A; Nogach, L V; Norman, B; Nurushev, S B; Odyniec, G; Ogawa, A; Okorokov, V; Oldenburg, M; Olson, D; Paic, G; Pandey, S U; Panebratsev, Y; Panitkin, S Y; Pavlinov, A I; Pawlak, T; Perevoztchikov, V; Peryt, W; Petrov, V A; Planinic, M; Pluta, J; Porile, N; Porter, J; Poskanzer, A M; Potrebenikova, E; Prindle, D; Pruneau, C; Putschke, J; Rai, G; Rakness, G; Ravel, O; Ray, R L; Razin, S V; Reichhold, D; Reid, J G; Renault, G; Retiere, F; Ridiger, A; Ritter, H G; Roberts, J B; Rogachevski, O V; Romero, J L; Rose, A; Roy, C; Rykov, V; Sakrejda, I; Salur, S; Sandweiss, J; Saulys, A C; Savin, I; Schambach, J; Scharenberg, R P; Schmitz, N; Schroeder, L S; Schüttauf, A; Schweda, K; Seger, J; Seliverstov, D; Seyboth, P; Shahaliev, E; Shestermanov, K E; Shimanskii, S S; Shvetcov, V S; Skoro, G; Smirnov, N; Snellings, R; Sorensen, P; Sowinski, J; Spinka, H M; Srivastava, B; Stephenson, E J; Stock, R; Stolpovsky, A; Strikhanov, M; Stringfellow, B; Struck, C; Suaide, A A P; Sugarbaker, E; Suire, C; Sumbera, M; Surrow, B; Symons, T J M; de Toledo, A Szanto; Szarwas, P; Tai, A; Takahashi, J; Tang, A H; Thomas, J H; Thompson, M; Tikhomirov, V; Tokarev, M; Tonjes, M B; Trainor, T A; Trentalange, S; Tribble, R E; Trofimov, V; Tsai, O; Ullrich, T; Underwood, D G; Van Buren, G; VanderMolen, A M; Vasilevski, I M; Vasiliev, A N; Vigdor, S E; Voloshin, S A; Wang, F; Ward, H; Watson, J W; Wells, R; Westfall, G D; Whitten, C; Wieman, H; Willson, R; Wissink, S W; Witt, R; Wood, J; Xu, N; Xu, Z; Yakutin, A E; Yamamoto, E; Yang, J; Yepes, P; Yurevich, V I; Zanevski, Y V; Zborovský, I; Zhang, H; Zhang, W M; Zoulkarneev, R; Zubarev, A N
2002-08-26
We report the first measurement of strange (Lambda) and antistrange (Lambda macro) baryon production from square root of [s(NN)]=130 GeV Au+Au collisions at the Relativistic Heavy Ion Collider (RHIC). Rapidity density and transverse mass distributions at midrapidity are presented as a function of centrality. The yield of Lambda and Lambda; hyperons is found to be approximately proportional to the number of negative hadrons. The production of Lambda; hyperons relative to negative hadrons increases very rapidly with transverse momentum. The magnitude of the increase cannot be described by existing hadronic string fragmentation models alone. PMID:12190390
Properties of the Lambda(1405) Measured at CLAS
Kei Moriya, Reinhard Schumacher
2010-08-01
The nature of the Lambda(1405) with its peculiar mass distribution is not well understood, and studies have shown that it may posess strong dynamical components. Using the CLAS detector system in Hall B at Jefferson Lab, we have performed a high statistics measurement of the photoproduction of K+Lambda(1405) using a proton target. The reconstructed invariant mass distribution seen in the various [summation]pi decay modes has been measured, as well as the differential cross section ((d sigma)/(dt)). Various aspects of our analysis are discussed, as well as future prospects to further enhance the precision of the results
Observation of parity violation in the Omega- ---> Lambda K- decay
Lu, L.C.; Burnstein, R.A.; Chakravorty, A.; Chen, Y.C.; Choong, W.-S.; Clark, K.; Dukes, E.C.; Durandet, C.; Felix, J.; Fu, Y.; Gidal, G.; Gustafson, H.R.; Holmstrom, T.; Huang, M.; James, C.; Jenkins, C.M.; Jones, T.D.; Kaplan, D.M.; Longo, M.J.; Luebke, W.; Luk, K.-B.; /Taiwan, Inst. Phys. /UC, Berkeley /Fermilab /Guanajuato U. /IIT, Chicago /Lausanne U. /LBL, Berkeley /Michigan U. /South Alabama U. /Virginia U.
2005-05-01
The {alpha} decay parameter in the process {Omega}{sup -} {yields} {Lambda}K{sup -} has been measured from a sample of 4.50 million unpolarized {Omega}{sup -} decays recorded by the HyperCP (E871) experiment at Fermilab and found to be [1.78 {+-} 0.19(stat) {+-} 0.16(syst)] x 10{sup -2}. This is the first unambiguous evidence for a nonzero {alpha} decay parameter, and hence parity violation, in the {Omega}{sup -} {Lambda}K{sup -} decay.
Approaching {lambda} without fine-tuning
Matarrese, Sabino; Baccigalupi, Carlo; Perrotta, Francesca
2004-09-15
We address the fine-tuning problem of dark energy cosmologies which arises when the dark energy density needs to initially lie in a narrow range in order for its present value to be consistent with observations. As recently noticed, this problem becomes particularly severe in canonical quintessence scenarios, when trying to reproduce the behavior of a cosmological constant, i.e., when the dark energy equation of state w{sub Q} approaches -1: these models may be reconciled with a large basin of attraction only by requiring a rapid evolution of w{sub Q} at low redshifts, which is in conflict with the most recent estimates from type Ia Supernovae discovered by Hubble space telescope. Next, we focus on scalar-tensor theories of gravity, discussing the implications of a coupling between the quintessence scalar field and the Ricci scalar ('extended quintessence'). We show that, even if the equation of state today is very close to -1, by virtue of the scalar-tensor coupling the quintessence trajectories still possess the attractive feature which allows to reach the present level of cosmic acceleration starting by a set of initial conditions which covers tens of orders of magnitude; this effect, entirely of gravitational origin, represents a new important consequence of the possible coupling between dark energy and gravity. We illustrate this effect in typical extended quintessence scenarios.
ITER safety challenges and opportunities
Piet, S.J.
1991-01-01
Results of the Conceptual Design Activity (CDA) for the International Thermonuclear Experimental Reactor (ITER) suggest challenges and opportunities. ITER is capable of meeting anticipated regulatory dose limits,'' but proof is difficult because of large radioactive inventories needing stringent radioactivity confinement. We need much research and development (R D) and design analysis to establish that ITER meets regulatory requirements. We have a further opportunity to do more to prove more of fusion's potential safety and environmental advantages and maximize the amount of ITER technology on the path toward fusion power plants. To fulfill these tasks, we need to overcome three programmatic challenges and three technical challenges. The first programmatic challenge is to fund a comprehensive safety and environmental ITER R D plan. Second is to strengthen safety and environment work and personnel in the international team. Third is to establish an external consultant group to advise the ITER Joint Team on designing ITER to meet safety requirements for siting by any of the Parties. The first of the three key technical challenges is plasma engineering -- burn control, plasma shutdown, disruptions, tritium burn fraction, and steady state operation. The second is the divertor, including tritium inventory, activation hazards, chemical reactions, and coolant disturbances. The third technical challenge is optimization of design requirements considering safety risk, technical risk, and cost. Some design requirements are now too strict; some are too lax. Fuel cycle design requirements are presently too strict, mandating inappropriate T separation from H and D. Heat sink requirements are presently too lax; they should be strengthened to ensure that maximum loss of coolant accident temperatures drop.
LAMBDA Polarization with a Transversely Polarized Proton Target at the COMPASS Experiment
Negrini, Teresa
2009-08-04
The transverse polarization of LAMBDA and LAMBDA-bar hyperons is investigated at the COMPASS experiment at CERN. In 2007 a 160 GeV/c longitudinally polarized muon beam and a transversely polarized NH{sub 3} target were employed to study events in semi-inclusive deep-inelastic scattering. Preliminary results for the LAMBDA and LAMBDA-bar polarizations extracted from this new data set are presented as a function of x{sub Bj} and z. The polarizations of LAMBDA and LAMBDA-bar are compatible with zero within their error bars and no dependence on x{sub Bj} or z is observed.
Analysis of the velocity law in the wind of the Be star Lambda Pavonis
NASA Technical Reports Server (NTRS)
Chen, Haiqi; Ringuelet, Adela; Sahade, Jorge; Kondo, Yoji
1989-01-01
This paper reanalyzes the IUE spectra of Lambda Pavonis secured in 1982 (Sahade et al.). It is found that the profiles of the broad UV lines are either rotationally broadened or nonrotationally broadened and that the rotationally broadened profiles can be sorted out in two groups characterized by rotational velocity values of 170 km/s and of 210 km/s, respectively. From the analysis of the rotational and of the radial velocities it is possible to distinguish two regions in the extended atmosphere of the star, namely, a region which is rotating and a region which is expanding. In the rotating region, the radial velocities are about zero, and the rotational velocity increases from 170 km/s to 250 km/s. In the expanding region, the rotational energy dissipates, the wind is accelerated to a maximum of -155 km/s, and farther out it decelerates.
New results for the lifetimes of the D(, F(, and. lambda. /sub c//sup +/ particles
Ushida, N.; Kondo, T.; Fujioka, G.; Fukushima, H.; Takahashi, Y.; Tatsumi, S.; Yokoyama, C.; Homma, Y.; Tsuzuki, Y.; Bahk, S.Y.
1983-12-26
In an experiment measuring charmed-particle lifetimes with use of a hybrid-emulsion spectrometer in the wide-band neutrino beam at the Fermi National Accelerator Laboratory, 1248 neutrino and antineutrino interactions have been located. Twenty-three charged charm decay candidates have been reconstructed, from which we determine the lifetime of the D/sup + -/ to be 11.5/sub -3.5//sup +7.5/ x 10/sup -13/ s, that of the F/sup + -/ to be 1.9/sub -0.7//sup +1.3/ x 10/sup -13/ s, and that of the ..lambda../sub c//sup +/ to be 2.3/sub -0.6//sup +1.0/ x 10/sup -13/ s.
Status of PRIMA, the test facility for ITER neutral beam injectors
NASA Astrophysics Data System (ADS)
Sonato, P.; Antoni, V.; Bigi, M.; Chitarin, G.; Luchetta, A.; Marcuzzi, D.; Pasqualotto, R.; Pomaro, N.; Serianni, G.; Toigo, V.; Zaccaria, P.; ITER International Team
2013-02-01
The ITER project requires additional heating by two neutral beam injectors, each accelerating to 1MV a 40A beam of negative deuterons, delivering to the plasma about 17MW up to one hour. As these requirements have never been experimentally met, it was decided to build a test facility, PRIMA (Padova Research on ITER Megavolt Accelerator), in Italy, including a full-size negative ion source, SPIDER, and a prototype of the whole ITER injector, MITICA, aiming to develop the heating injectors to be installed in ITER. The Japan and the India Domestic Agencies participate in the PRIMA enterprise; European laboratories, such as KIT-Karlsruhe, IPP-Garching, CCFE-Culham, CEA-Cadarache and others are also cooperating. In the paper the main requirements are discussed and the design of the main components and systems are described.
ITER Construction--Plant System Integration
Tada, E.; Matsuda, S.
2009-02-19
This brief paper introduces how the ITER will be built in the international collaboration. The ITER Organization plays a central role in constructing ITER and leading it into operation. Since most of the ITER components are to be provided in-kind from the member countries, integral project management should be scoped in advance of real work. Those include design, procurement, system assembly, testing, licensing and commissioning of ITER.
GRAVITATIONAL LENSING CORRECTIONS IN FLAT {Lambda}CDM COSMOLOGY
Kantowski, Ronald; Chen Bin; Dai Xinyu E-mail: Bin.Chen-1@ou.ed
2010-08-01
We compute the deflection angle to order (m/r {sub 0}){sup 2} and m/r{sub 0} x {Lambda}r {sup 2}{sub 0} for a light ray traveling in a flat {Lambda}CDM cosmology that encounters a completely condensed mass region. We use a Swiss cheese model for the inhomogeneities and find that the most significant correction to the Einstein angle occurs not because of the nonlinear terms but instead occurs because the condensed mass is embedded in a background cosmology. The Swiss cheese model predicts a decrease in the deflection angle of {approx}2% for weakly lensed galaxies behind the rich cluster A1689 and that the reduction can be as large as {approx}5% for similar rich clusters at z {approx} 1. Weak-lensing deflection angles caused by galaxies can likewise be reduced by as much as {approx}4%. We show that the lowest order correction in which {Lambda} appears is proportional to m/r{sub 0} x {radical}({Lambda}r{sub 0}{sup 2}) and could cause as much as a {approx}0.02% increase in the deflection angle for light that passes through a rich cluster. The lowest order nonlinear correction in the mass is proportional to m/r{sub 0}x{radical}(m/r{sub 0}) and can increase the deflection angle by {approx}0.005% for weak lensing by galaxies.
X-Ray Flare Characteristics in lambda Eridani
NASA Technical Reports Server (NTRS)
Smith, Myron A.
1997-01-01
This proposal was for a joint X-ray/ultraviolet/ground-based study of the abnormal Be star lambda Eri, which has previously shown evidence of X-ray flaring from ROSAT observations in 1991. The X-ray component consisted of observations from both the ASCA and ROSAT satellites.
X-Ray Flare Characteristics in Lambda Eridani
NASA Technical Reports Server (NTRS)
Smith, Myron A.
1997-01-01
This proposal was for a joint X-ray/ultraviolet/ground-based study of the abnormal Be star lambda Eri, which has previously shown evidence of X-ray flaring from ROSAT observations in 1991. The X-ray component consisted of observations from both the ASCA and ROSAT satellites.
First Observation of the {Lambda}(1405) Line Shape in Electroproduction
Lu, Haiyun; Schumacher, Reinhard A.
2013-10-01
We report the first observation of the line shape of the {Lambda}(1405) from electroproduction, and show that it is not a simple Breit-Wigner resonance. Electroproduction of K{sup +}{Lambda}(1405) off the proton was studied by using data from CLAS at Jefferson Lab in the range 1.0Lambda}(1405) and p{pi}{sup 0} of the {Sigma}{sup +}. Neither the standard Particle Data Group resonance parameters, nor free parameters fitting to a single Breit-Wigner resonance represent the line shape. In our fits, the line shape corresponds approximately to predictions of a two-pole meson-baryon picture of the {Lambda}(1405), with a lower mass pole near 1368 MeV/c{sup 2} and a higher mass pole near 1423 MeV/c{sup 2}. Furthermore, with increasing photon virtuality the mass distribution shifts toward the higher mass pole.
Extracting Low-Lying Lambda Resonances Using Correlation Matrix Techniques
Menadue, Benjamin J.; Kamleh, Waseem; Leinweber, Derek B.; Mahbub, M. S.
2011-05-24
The lowest-lying negative-parity state of the Lambda is investigated in (2+1)-flavour full-QCD on the PACS-CS configurations made available through the ILDG. We show that a variational analysis using multiple source and sink smearings can extract a state lying lower than that obtained by using a standard fixed smeared source and sink operator alone.
Healing length near the lambda point in liquid helium
Lea, M.J.; Spencer, D.S.; Fozooni, P.
1989-04-01
Viscous shear waves have been used to probe the spatial variation and healing of the viscosity and superfluid density near a solid wall in bulk He I, bulk He II, and in saturated superfluid films with thicknesses from 14 to 24 nm. The shear waves were generated at 20 and 34 MHz with an AT-cut quartz crystal resonator, and the transverse-acoustic impedance of the helium was measured at temperatures T close to the lambda point at T/sub lambda/. In bulk He II the results confirm a previous measurement of the healing length a(T) = (0.094 +- 0.002)epsilon/sup -2/3/ nm, where epsilon = chemically bond1-T/T/sub lambda/chemically bond. In bulk He I the measurements suggest that the viscosity exhibits healing above T/sub lambda/ near a solid wall with a similar healing length as in He II. Healing effects were observed below the superfluid transition temperature in the films and are also described by the same healing length as in the bulk liquid.
ITER project and fusion technology
NASA Astrophysics Data System (ADS)
Takatsu, H.
2011-09-01
In the sessions of ITR, FTP and SEE of the 23rd IAEA Fusion Energy Conference, 159 papers were presented in total, highlighted by the remarkable progress of the ITER project: ITER baseline has been established and procurement activities have been started as planned with a target of realizing the first plasma in 2019; ITER physics basis is sound and operation scenarios and operational issues have been extensively studied in close collaboration with the worldwide physics community; the test blanket module programme has been incorporated into the ITER programme and extensive R&D works are ongoing in the member countries with a view to delivering their own modules in a timely manner according to the ITER master schedule. Good progress was also reported in the areas of a variety of complementary activities to DEMO, including Broader Approach activities and long-term technology. This paper summarizes the highlights of the papers presented in the ITR, FTP and SEE sessions with a minimum set of background information.
John Womersley
2003-08-21
I describe the future accelerator facilities that are currently foreseen for electroweak scale physics, neutrino physics, and nuclear structure. I will explore the physics justification for these machines, and suggest how the case for future accelerators can be made.
Construction Safety Forecast for ITER
cadwallader, lee charles
2006-11-01
The International Thermonuclear Experimental Reactor (ITER) project is poised to begin its construction activity. This paper gives an estimate of construction safety as if the experiment was being built in the United States. This estimate of construction injuries and potential fatalities serves as a useful forecast of what can be expected for construction of such a major facility in any country. These data should be considered by the ITER International Team as it plans for safety during the construction phase. Based on average U.S. construction rates, ITER may expect a lost workday case rate of < 4.0 and a fatality count of 0.5 to 0.9 persons per year.
Error Field Correction in ITER
Park, Jong-kyu; Boozer, Allen H.; Menard, Jonathan E.; Schaffer, Michael J.
2008-05-22
A new method for correcting magnetic field errors in the ITER tokamak is developed using the Ideal Perturbed Equilibrium Code (IPEC). The dominant external magnetic field for driving islands is shown to be localized to the outboard midplane for three ITER equilibria that represent the projected range of operational scenarios. The coupling matrices between the poloidal harmonics of the external magnetic perturbations and the resonant fields on the rational surfaces that drive islands are combined for different equilibria and used to determine an ordered list of the dominant errors in the external magnetic field. It is found that efficient and robust error field correction is possible with a fixed setting of the correction currents relative to the currents in the main coils across the range of ITER operating scenarios that was considered.
Attaya, H.; Gohar, Y.; Smith, D.
1990-09-01
Activation analysis has been made for the US ITER design. The radioactivity and the decay heat have been calculated, during operation and after shutdown for the two ITER phases, the Physics Phase and the Technology Phase. The Physics Phase operates about 24 full power days (FPDs) at fusion power level of 1100 MW and the Technology Phase has 860 MW fusion power and operates for about 1360 FPDs. The point-wise gamma sources have been calculated everywhere in the reactor at several times after shutdown of the two phases and are then used to calculate the biological dose everywhere in the reactor. Activation calculations have been made also for ITER divertor. The results are presented for different continuous operation times and for only one pulse. The effect of the pulsed operation on the radioactivity is analyzed. 6 refs., 12 figs., 1 tab.
Convex accelerated maximum entropy reconstruction
NASA Astrophysics Data System (ADS)
Worley, Bradley
2016-04-01
Maximum entropy (MaxEnt) spectral reconstruction methods provide a powerful framework for spectral estimation of nonuniformly sampled datasets. Many methods exist within this framework, usually defined based on the magnitude of a Lagrange multiplier in the MaxEnt objective function. An algorithm is presented here that utilizes accelerated first-order convex optimization techniques to rapidly and reliably reconstruct nonuniformly sampled NMR datasets using the principle of maximum entropy. This algorithm - called CAMERA for Convex Accelerated Maximum Entropy Reconstruction Algorithm - is a new approach to spectral reconstruction that exhibits fast, tunable convergence in both constant-aim and constant-lambda modes. A high-performance, open source NMR data processing tool is described that implements CAMERA, and brief comparisons to existing reconstruction methods are made on several example spectra.
Nichols, J.D.; Hines, J.E.
2002-01-01
We first consider the estimation of the finite rate of population increase or population growth rate, lambda sub i, using capture-recapture data from open populations. We review estimation and modelling of lambda sub i under three main approaches to modelling open-population data: the classic approach of Jolly (1965) and Seber (1965), the superpopulation approach of Crosbie & Manly (1985) and Schwarz & Arnason (1996), and the temporal symmetry approach of Pradel (1996). Next, we consider the contributions of different demographic components to lambda sub i using a probabilistic approach based on the composition of the population at time i + 1 (Nichols et al., 2000b). The parameters of interest are identical to the seniority parameters, gamma sub i, of Pradel (1996). We review estimation of gamma sub i under the classic, superpopulation, and temporal symmetry approaches. We then compare these direct estimation approaches for lambda sub i and gamma sub i with analogues computed using projection matrix asymptotics. We also discuss various extensions of the estimation approaches to multistate applications and to joint likelihoods involving multiple data types.
Wurden, G A
2009-01-01
For future machines, the plasma stored energy is going up by factors of 20-40x, and plasma currents by 2-3x, while the surface to volume ratio is at the same time decreasing. Therefore the disruption forces, even for constant B, (which scale like IxB), and associated possible localized heating on machine components, are more severe. Notably, Tore Supra has demonstrated removal of more than 1 GJ of input energy, over nearly a 400 second period. However, the instantaneous stored energy in the Tore Supra system (which is most directly related to the potential for disruption damage) is quite small compared to other large tokamaks. The goal of ITER is routinely described as studying DT burning plasmas with a Q {approx} 10. In reality, ITER has a much more important first order mission. In fact, if it fails at this mission, the consequences are that ITER will never get to the eventual stated purpose of studying a burning plasma. The real mission of ITER is to study (and demonstrate successfully) plasma control with {approx}10-17 MA toroidal currents and {approx}100-400 MJ plasma stored energy levels in long-pulse scenarios. Before DT operation is ever given a go-ahead in ITER, the reality is that ITER must demonstrate routine and reliable control of high energy hydrogen (and deuterium) plasmas. The difficulty is that ITER must simultaneously deal with several technical problems: (1) heat removal at the plasma/wall interface, (2) protection of the wall components from off-normal events, and (3) generation of dust/redeposition of first wall materials. All previous tokamaks have encountered hundred's of major disruptions in the course of their operation. The consequences of a few MA of runaway electrons (at 20-50 MeV) being generated in ITER, and then being lost to the walls are simply catastrophic. They will not be deposited globally, but will drift out (up, down, whatever, depending on control system), and impact internal structures, unless 'ameliorated'. Basically, this
Iterated binomial sums and their associated iterated integrals
NASA Astrophysics Data System (ADS)
Ablinger, J.; Blümlein, J.; Raab, C. G.; Schneider, C.
2014-11-01
We consider finite iterated generalized harmonic sums weighted by the binomial binom{2k}{k} in numerators and denominators. A large class of these functions emerges in the calculation of massive Feynman diagrams with local operator insertions starting at 3-loop order in the coupling constant and extends the classes of the nested harmonic, generalized harmonic, and cyclotomic sums. The binomially weighted sums are associated by the Mellin transform to iterated integrals over square-root valued alphabets. The values of the sums for N → ∞ and the iterated integrals at x = 1 lead to new constants, extending the set of special numbers given by the multiple zeta values, the cyclotomic zeta values and special constants which emerge in the limit N → ∞ of generalized harmonic sums. We develop algorithms to obtain the Mellin representations of these sums in a systematic way. They are of importance for the derivation of the asymptotic expansion of these sums and their analytic continuation to N in {C}. The associated convolution relations are derived for real parameters and can therefore be used in a wider context, as, e.g., for multi-scale processes. We also derive algorithms to transform iterated integrals over root-valued alphabets into binomial sums. Using generating functions we study a few aspects of infinite (inverse) binomial sums.
About the scheme of the infrared FEL system for the accelerator based on HF wells
Kabanov, V.S.; Dzergach, A.I.
1995-12-31
Accelerators, based on localization of plasmoids in the HF wells (RF traps) of the axially-symmetric electromagnetic field E {sub omn} in an oversized (m,n>>1) resonant system, can give accelerating gradients {approximately}100 kV/{lambda}, e.g. 10 GV/m if {lambda}=10 {mu}m. One of possible variants of HF feeding for these accelerators is based on using the powerful infrared FEL System with 2 frequencies. The corresponding FEL`s may be similar to the Los Alamos compact Advanced FEL ({lambda}{sub 1,2}{approximately}10 pm, e-beam energy {approximately}15 MeV, e-beam current {approximately}100 A). Their power is defined mainly by the HF losses in the resonant system of the supposed accelerator.
Delayed Over-Relaxation for iterative methods
NASA Astrophysics Data System (ADS)
Antuono, M.; Colicchio, G.
2016-09-01
We propose a variant of the relaxation step used in the most widespread iterative methods (e.g. Jacobi Over-Relaxation, Successive Over-Relaxation) which combines the iteration at the predicted step, namely (n + 1), with the iteration at step (n - 1). We provide a theoretical analysis of the proposed algorithm by applying such a delayed relaxation step to a generic (convergent) iterative scheme. We prove that, under proper assumptions, this significantly improves the convergence rate of the initial iterative method. As a relevant example, we apply the proposed algorithm to the solution of the Poisson equation, highlighting the advantages in comparison with classical iterative models.
ODE System Solver W. Krylov Iteration & Rootfinding
1991-09-09
LSODKR is a new initial value ODE solver for stiff and nonstiff systems. It is a variant of the LSODPK and LSODE solvers, intended mainly for large stiff systems. The main differences between LSODKR and LSODE are the following: (a) for stiff systems, LSODKR uses a corrector iteration composed of Newton iteration and one of four preconditioned Krylov subspace iteration methods. The user must supply routines for the preconditioning operations, (b) Within the corrector iteration,more » LSODKR does automatic switching between functional (fixpoint) iteration and modified Newton iteration, (c) LSODKR includes the ability to find roots of given functions of the solution during the integration.« less
Continued Fractions and Iterative Processes.
ERIC Educational Resources Information Center
Bevis, Jean H.; Boal, Jan L.
1982-01-01
Continued fractions and associated sequences are viewed to constitute a rich area of study for mathematics students, by supporting instruction on algebraic and computational skills, mathematical induction, convergence of sequences, and interpretation of function graphs. An iterative method of approximating square roots opens suggestions for…
Energetic ions in ITER plasmas
NASA Astrophysics Data System (ADS)
Pinches, S. D.; Chapman, I. T.; Lauber, Ph. W.; Oliver, H. J. C.; Sharapov, S. E.; Shinohara, K.; Tani, K.
2015-02-01
This paper discusses the behaviour and consequences of the expected populations of energetic ions in ITER plasmas. It begins with a careful analytic and numerical consideration of the stability of Alfvén Eigenmodes in the ITER 15 MA baseline scenario. The stability threshold is determined by balancing the energetic ion drive against the dominant damping mechanisms and it is found that only in the outer half of the plasma ( r / a > 0.5 ) can the fast ions overcome the thermal ion Landau damping. This is in spite of the reduced numbers of alpha-particles and beam ions in this region but means that any Alfvén Eigenmode-induced redistribution is not expected to influence the fusion burn process. The influence of energetic ions upon the main global MHD phenomena expected in ITER's primary operating scenarios, including sawteeth, neoclassical tearing modes and Resistive Wall Modes, is also reviewed. Fast ion losses due to the non-axisymmetric fields arising from the finite number of toroidal field coils, the inclusion of ferromagnetic inserts, the presence of test blanket modules containing ferromagnetic material, and the fields created by the Edge Localised Mode (ELM) control coils in ITER are discussed. The greatest losses and associated heat loads onto the plasma facing components arise due to the use of the ELM control coils and come from neutral beam ions that are ionised in the plasma edge.
Networking Theories by Iterative Unpacking
ERIC Educational Resources Information Center
Koichu, Boris
2014-01-01
An iterative unpacking strategy consists of sequencing empirically-based theoretical developments so that at each step of theorizing one theory serves as an overarching conceptual framework, in which another theory, either existing or emerging, is embedded in order to elaborate on the chosen element(s) of the overarching theory. The strategy is…
Layout compliance for triple patterning lithography: an iterative approach
NASA Astrophysics Data System (ADS)
Yu, Bei; Garreton, Gilda; Pan, David Z.
2014-10-01
As the semiconductor process further scales down, the industry encounters many lithography-related issues. In the 14nm logic node and beyond, triple patterning lithography (TPL) is one of the most promising techniques for Metal1 layer and possibly Via0 layer. As one of the most challenging problems in TPL, recently layout decomposition efforts have received more attention from both industry and academia. Ideally the decomposer should point out locations in the layout that are not triple patterning decomposable and therefore manual intervention by designers is required. A traditional decomposition flow would be an iterative process, where each iteration consists of an automatic layout decomposition step and manual layout modification task. However, due to the NP-hardness of triple patterning layout decomposition, automatic full chip level layout decomposition requires long computational time and therefore design closure issues continue to linger around in the traditional flow. Challenged by this issue, we present a novel incremental layout decomposition framework to facilitate accelerated iterative decomposition. In the first iteration, our decomposer not only points out all conflicts, but also provides the suggestions to fix them. After the layout modification, instead of solving the full chip problem from scratch, our decomposer can provide a quick solution for a selected portion of layout. We believe this framework is efficient, in terms of performance and designer friendly.
Active beam spectroscopy for ITER
NASA Astrophysics Data System (ADS)
von Hellermann, M. G.; Barnsley, R.; Biel, W.; Delabie, E.; Hawkes, N.; Jaspers, R.; Johnson, D.; Klinkhamer, F.; Lischtschenko, O.; Marchuk, O.; Schunke, B.; Singh, M. J.; Snijders, B.; Summers, H. P.; Thomas, D.; Tugarinov, S.; Vasu, P.
2010-11-01
Since the first feasibility studies of active beam spectroscopy on ITER in 1995 the proposed diagnostic has developed into a well advanced and mature system. Substantial progress has been achieved on the physics side including comprehensive performance studies based on an advanced predictive code, which simulates active and passive features of the expected spectral ranges. The simulation has enabled detailed specifications for an optimized instrumentation and has helped to specify suitable diagnostic neutral beam parameters. Four ITER partners share presently the task of developing a suite of ITER active beam diagnostics, which make use of the two 0.5 MeV/amu 18 MW heating neutral beams and a dedicated 0.1 MeV/amu, 3.6 MW diagnostic neutral beam. The IN ITER team is responsible for the DNB development and also for beam physics related aspects of the diagnostic. The RF will be responsible for edge CXRS system covering the outer region of the plasma (1> r/ a>0.4) using an equatorial observation port, and the EU will develop the core CXRS system for the very core (0< r/ a<0.7) using a top observation port. Thus optimum radial resolution is ensured for each system with better than a/30 resolution. Finally, the US will develop a dedicated MSE system making use of the HNBs and two equatorial ports. With appropriate modification, these systems could also potentially provide information on alpha particle slowing-down features. . On the engineering side, comprehensive preparations were made involving the development of an observation periscope, a neutron labyrinth optical system and design studies for remote maintenance including the exchange of the first mirror assembly, a critical issue for the operation of the CXRS diagnostic in the harsh ITER environment. Additionally, an essential change of the orientation of the DNB injection angle and specification of suitable blanket aperture has been made to avoid trapped particle damage to the first wall.
Methods for identification of recombinants of phage lambda.
Sanzey, B; Mercereau, O; Ternynck, T; Kourilsky, P
1976-10-01
Two methods are described which allow the screening of a large number of phage plaques for a specific DNA sequence carried by the phage or a specific antigen produced within the phage plaque. These methods were set up with lambda and lambdalac phages. Phage plaques were transferred onto nitrocellulose filters by desiccation in 0.1 M NaOH, and the lac sequence was detected by hybridization to radioactive lac mRNA. Beta-Galactosidase was detected by reaction with anti-beta-galactosidase immune serum included in the soft agar of the titration plates; the precipitate thus formed was revealed by means of enzyme-coupled antibodies and in situ coloration. These methods are potentially useful for the identification of lambda transducers, including those which are generated by in vitro recombination with eukaryotic DNA.
A microscopic theory of the lambda transition, II
NASA Astrophysics Data System (ADS)
Toyoda, Tadashi
1983-08-01
The previously proposed finite temperature field theory of the lambda transition based on the Schwinger functional method is investigated further. A systematic method for calculating the higher-order loop terms is presented by introducing the one-loop Green's functions, which are found to be a natural finite temperature extension of the Beliaev-Hugenholtz-Pines-Gavoret-Nozières zero-temperature Green's functions. The application of the finite temperature loop expansion to the dynamical properties is presented by calculating the retarded density correlation functions at the one-loop level. The result gives a microscopic basis for the form of the dynamical structure factor recently proposed by Woods and Svensson. From a general point of view, without using any approximations or model interactions, Goldstone's theorem for the lambda transition at finite temperature is presented.
Fourth generation effect on {Lambda}{sub b} decays
Mohanta, R.; Giri, A. K.
2010-11-01
The rare decays of the {Lambda}{sub b} baryon governed by the quark level transitions b{yields}s are investigated in the fourth quark generation model popularly known as SM4. Recently it has been shown that SM4, which is a very simple extension of the standard model, can successfully explain several anomalies observed in the CP violation parameters of B and B{sub s} mesons. We find that in this model due to the additional contributions coming from the heavy t{sup '} quark in the loop, the branching ratios and other observables in rare {Lambda}{sub b} decays deviate significantly from their standard model values. Some of these modes are within the reach of the LHCb experiment and search for such channels is strongly argued.
Lambda modes of the neutron diffusion equation in hexagonal geometry
Barrachina, T.; Ginestar, D.; Verdu, G.
2006-07-01
A nodal collocation method is proposed to compute the dominant Lambda modes of nuclear reactor core with a hexagonal geometry. This method is based on a triangular mesh and assumes that the neutronic flux can be approximated as a finite expansion in terms of Dubiner's polynomials. The method transforms the initial differential eigenvalue problem into a generalized algebraic one, from which the dominant modes of the reactor can be computed. The performance of the method is tested with two benchmark problems. (authors)
Lambda-carrageenan: a novel chiral selector for capillary electrophoresis.
Beck, G M; Neau, S H
1996-01-01
Lambda-carrageenan, a linear high molecular weight sulfated polysaccharide, has been employed as a chiral selector in capillary electrophoresis for the separation of enantiomers of weakly basic pharmaceutical compounds. The racemic compounds that were enantioresolved included propranolol, pindolol, tryptophanol, laudanosine and laudanosoline. In addition, the diastereomeric pair of cinchonine and cinchonidine were also resolved. Method conditions such as buffer pH, electrolyte concentration, column temperature, and chiral selector concentration were found to be important for improvement of enantioselectivity.
Rubberlike Dynamics in Sulphur above the {lambda}-Transition Temperature
Monaco, G.; Crapanzano, L.; Crichton, W.; Mezouar, M.; Verbeni, R.; Bellissent, R.
2005-12-16
The high-frequency acoustic dynamics of sulfur across the liquid-liquid, {lambda} transition has been studied using inelastic x-ray scattering. The combination of these high-frequency data with lower frequency, literature data indicates that liquid sulfur develops, in the high-temperature, polymeric solution phase, some characteristic features of a rubber. In particular, entanglement coupling among polymeric chains plays a relevant role in the dynamics of this liquid phase.
Application of nonlinear Krylov acceleration to radiative transfer problems
Till, A. T.; Adams, M. L.; Morel, J. E.
2013-07-01
The iterative solution technique used for radiative transfer is normally nested, with outer thermal iterations and inner transport iterations. We implement a nonlinear Krylov acceleration (NKA) method in the PDT code for radiative transfer problems that breaks nesting, resulting in more thermal iterations but significantly fewer total inner transport iterations. Using the metric of total inner transport iterations, we investigate a crooked-pipe-like problem and a pseudo-shock-tube problem. Using only sweep preconditioning, we compare NKA against a typical inner / outer method employing GMRES / Newton and find NKA to be comparable or superior. Finally, we demonstrate the efficacy of applying diffusion-based preconditioning to grey problems in conjunction with NKA. (authors)
MacNeil, D; Howe, M M; Brill, W J
1980-01-01
Seve lambda dnif specialized transducing bacteriophages were isolated from Escherichia coli strains containing plasmids carrying the his-nif region of Klebsiella pneumoniae. These phages collectively carry deoxyribonucleic acid for all of the genes in the nif regulon and adjacent deoxyribonucleic acid of K. pneumoniae. The phages were isolated by using Mu insertions in the nif region to direct the integration of lambda pMu phages in nif via formation of lambda pMu-Mu dilysogens which, upon induction, yielded lambda dnif phages. This procedure should be generally applicable for isolating lambda specialized transducing phages carrying genes from E. coli or other bacteria. PMID:6245064
({lambda}, p) Spectrum Analysis in p+A Interactions at 10 GeV/c
Aslanyan, P. Zh.; Emelyanenko, V. N.
2007-06-13
Experimental data from the 2m propane bubble chamber have been analyzed for exotic baryon states search. A number of peculiarities were found in the effective mass spectra of: {lambda}{pi}+({sigma}*+(1382),PDG), {lambda}p and {lambda}pp subsystems. A few events detected on the photographs of the propane bubble chamber exposed to a 10 GeV/c proton beam, were interpreted as S=-2 H0 light(
Lambda-Nucleon Potential Calculated from Lattice QCD
Nemura, Hidekatsu
2011-10-21
We present our studies of Lambda-Nucleon ({Lambda}N) interaction by using lattice QCD. The equal-time Nambu-Bethe-Salpeter (NBS) amplitude of the lowest energy scattering state of a proton-{Lambda} system is calculated from lattice QCD. In this report, two different types of gauge configurations are employed: (i) Quenched QCD configurations at {beta} = 5.7 (a = 0.1416(9) fm) on a 32{sup 3}x48 lattice, whose spatial volume is (4.5 fm){sup 3}.(ii)2+1 flavor full QCD configurations generated by the PACS-CS collaboration at {beta} = 1.9 (a = 0.0907(13) fm) on a 32{sup 3}x64 lattice, whose spatial volume is (2.90 fm){sup 3}. The spin-singlet central potential is calculated from the NBS wave function for the spin J = 0 state, whereas the spin-triplet central potential as well as the tensor potential are deduced simultaneously from the NBS wave function for the spin J = 1 state by dividing it into the S-wave and the D-wave components.
Abulencia, A.; Adelman, J.; Affolder, T.; Akimoto, T.; Albrow, M.G.; Ambrose, D.; Amerio, S.; Amidei, D.; Anastassov, A.; Anikeev, K.; Annovi, A.; /Taiwan, Inst. Phys. /Argonne /Barcelona, IFAE /Baylor U. /INFN, Bologna /Bologna U. /Brandeis U. /UC, Davis /UCLA /UC, San Diego /UC, Santa Barbara
2006-09-01
The authors report a measurement of the {Lambda}{sub b}{sup 0} lifetime in the exclusive decay {Lambda}{sub b}{sup 0} {yields} J/{psi}{Lambda}{sup 0} in p{bar p} collisions at {radical}s = 1.96 TeV using an integrated luminosity of 1.0 fb{sup -1} of data collected by the CDF II detector at the Fermilab Tevatron. Using fully reconstructed decays, they measure {tau}({Lambda}{sub b}{sup 0}) = 1.593{sub -0.078}{sup +0.083}(stat.) {+-} 0.033(syst.) ps. This is the single most precise measurement of {tau}({Lambda}{sub b}{sup 0}) and is 3.2 {sigma} higher than the current world average.
Stable carbon isotope fractionation during the biodegradation of lambda-cyhalothrin.
Shen, Xiaoli; Xu, Zemin; Zhang, Xichang; Yang, Fangxing
2015-11-01
In this study, the microbial degradation of lambda-cyhalothrin in soil was investigated using compound-specific stable isotope analysis. The results revealed that lambda-cyhalothrin was biodegraded in soil under laboratory conditions. The half-lives of lambda-cyhalothrin were determined to be 49 and 161 days in non-sterile and sterile soils spiked with 2mg/kg lambda-cyhalothrin and 84 and 154 days in non-sterile and sterile soils spiked with 10mg/kg lambda-cyhalothrin, respectively. The biodegradation of lambda-cyhalothrin resulted in carbon isotope fractionation, which shifted from -29.0‰ to -26.5‰ in soil spiked with 2mg/kg lambda-cyhalothrin, and to -27.5‰ with 10mg/kg lambda-cyhalothrin. A relationship was established between the stable carbon isotope fraction and the residual concentrations of lambda-cyhalothrin by the Rayleigh equation in which the carbon isotope enrichment factor ε of the microbial degradation of lambda-cyhalothrin in the soil was calculated as -2.53‰. This study provides an approach to quantitatively evaluate the biodegradation of lambda-cyhalothrin in soil in field studies.
Study of the ^7_{Lambda}He hypernucleus in formalism of the Faddeev equations
Igor Filikhin; Vladimir M. Suslov; Branislav Vlahovic
2006-02-01
P-shell A = 7 hypernuclei are considered in the cluster {sub {Lambda}}{sup 5}He + N + N model. The folding procedure are applied to construct the {sub {Lambda}}{sup 5}He-N interaction. We use the OBE simulating NSC97f potential for {Lambda}N interaction and various phenomenological potentials for {alpha}{Lambda} interaction. Configuration space Faddeev calculations are performed for hyperon binding energy of the {sub {Lambda}}{sup 7}He(1/2{sup +}) and {sub {lambda}}{sup 7}Li(1/2{sup +} and 3/2{sup +}, T=0) nuclei. Predicted value for B{sub {Lambda}}({sub {Lambda}}{sup 7}He) is 5.35 MeV. This value is obtained when the {sup {Lambda}}{sup 6}He(2{sup -}) excitation energy is equal 0.26 MeV by the adjustment of pair {sub {Lambda}}{sup 5}He-N effective potential to reproduce the experimental value of the {sub {Lambda}}{sup 7}Li(3/2{sup +}) excitation energy. Our results are compared with those of E. Hiyama et al.
Three Dimensional Iterative Reconstruction Techniques in Positron Tomography.
NASA Astrophysics Data System (ADS)
Sloka, Scott
The acquisition of positron tomographic data in three dimensions is an improvement over the two dimensional acquisition of data because the greater the number of measurements taken of a stochastic process, the more accurately determined the desired parameter may be. This research pursues the goal of three dimensional image reconstruction in Positron Tomography using an iterative approach. This thesis has followed a systematic approach to the exploration of a system for three dimensional iterative reconstruction. System design parameters were discussed such as the advantages and disadvantages of iterative vs analytic methods, the implementation of two, three dimensional iterative algorithms, the selection of a ray passing method, and the choice of an analytic method for comparison to the iterative methods. Several qualitative and quantitative tests were used/developed and performed to analyse and compare the results. Three dimensional reconstruction in Positron Tomography using two iterative techniques (ART and ML-EM) was demonstrated. The ML-EM algorithm was adapted to satisfy the objective of equalizing the estimates with the measurements via division of the sampling density. A new multi-objective function methodology was developed for two dimensions and its extension to three dimensions discussed. A smoothly-varying Gaussian phantom was created for comparing artifacts from different ray passing methods. The analysis of voxel trends over many iterations was used. The use of the output from a two dimensional filtered backprojection algorithm as the seed for three dimensional algorithms to accelerate the reconstruction the was explored. The importance of the selection of a good ray ordering in ART and its effects on the total squared error were explored. For the phantoms studied in this thesis, the ML -EM algorithm tended to perform better under most conditions. This algorithm is slower than ART to achieve both a low total squared error and good contrast, but the
Iterative procedures for wave propagation in the frequency domain
Kim, Seongjai; Symes, W.W.
1996-12-31
A parallelizable two-grid iterative algorithm incorporating a domain decomposition (DD) method is considered for solving the Helmholtz problem. Since a numerical method requires choosing at least 6 to 8 grid points per wavelength, the coarse-grid problem itself is not an easy task for high frequency applications. We solve the coarse-grid problem using a nonoverlapping DD method. To accelerate the convergence of the iteration, an artificial damping technique and relaxation parameters are introduced. Automatic strategies for finding efficient parameters are discussed. Numerical results are presented to show the effectiveness of the method. It is numerically verified that the rate of convergence of the algorithm depends on the wave number sub-linearly and does not deteriorate as the mesh size decreases.
Search for CP violation in charged-Xi and Lambda hyperon decays
Holmstrom, T.; Leros, N.; Burnstein, R.A.; Chakravorty, A.; Chan, A.; Chen, Y.C.; Choong, W.S.; Clark, K.; Dukes, E.C.; Durandet, C.; Felix, J.; Fu, Y.; Gidal, G.; Gu, P.; Gustafson, H.R.; Ho, C.; Huang, M.; James, C.; Jenkins, C.M.; Jones, T.; Kaplan, D.M.; /Virginia U. /Lausanne U. /Taiwan, Inst. Phys. /UC, Berkeley /Fermilab /Guanajuato U. /IIT, Chicago /Lausanne U. /LBL, Berkeley /Michigan U. /South Alabama U. /Virginia U.
2004-12-01
The authors have compared the p and {bar p} angular distributions in 117 million {Xi}{sup -} {yields} {Lambda}{pi}{sup -} {yields} p{pi}{sup -}{pi}{sup -} and 41 million {Xi}{sup +} {yields} {bar {Lambda}}{pi}{sup +} {yields} {bar p}{pi}{sup +}{pi}{sup +} decays using a subset of the data from the HyperCP experiment (ES71) at Fermilab. They find no evidence of CP violation, with the direct-CP-violating parameter A{sub {Xi}{Lambda}} {triple_bond} (a{sub {Xi}}a{sub {Lambda}} - {bar a}{sub {Xi}}{bar a}{sub {Lambda}})/(a{sub {Xi}}a{sub {Lambda}} + {bar a}{sub {Xi}}{bar a}{sub {Lambda}}) = [0.0 {+-} 5.1(stat) {+-} 4.4(syst)] x 10{sup -4}.
[Bacteriophage lambda:lux: design and expression of bioluminescence in E. coli cells].
Duzhiĭ, D E; Zavil'gel'skiĭ, G B
1994-01-01
The bacteriophages lambda:lux and lambda:luxAB have been constructed by ligation of phage arms generated by BamHI or SalGI restriction endonucleases digestion of EMBL4 to BamHI digested plasmid pF1 lux+ or to SalGI digested plasmid pF2 lambda:luxA+B+. Cells of Escherichia coli prototrophic strain Cs were infected with lambda:lux or lambda:luxAB and intensity of bioluminiscence of the samples registered at different time intervals determined. The signal of bioluminiscence was first detected 15 min after infection and its level increased exponentially thereafter demonstrating replication of the lambda:lux bacteriophages. We have used the recombinant lambda:luxAB bacteriophage to detect the enteric indicator bacteria without enrichment in 15 min, provided that they are present at levels higher than 10(4).
A study of K{sub s} {Lambda} and {bar {Lambda}} production in hadronic Z{sup 0} decays
Baird, K.G.; SLD Collaboration
1994-08-01
We present a preliminary measurement of the inclusive production rates of K{sub s}, A and X hadrons produced in e{sup +}e{sup {minus}} annihilation at the Z{sup 0} pole. The analysis is based upon approximately 50K Z{sup 0} decays collected in the SLD experiment at SLAC in 1993. The observed rates of (K{sub s}) = 1.02 {plus_minus} 0.02 {plus_minus} 0.09 and ({Lambda}) + ({bar {Lambda}}) = 0.38 {plus_minus} 0.01 {plus_minus} 0.04 are consistent with previous measurements. Our differential cross section peak-position results are shown to be consistent with QCD predictions based on the modified leading logarithm approximation and local parton-hadron duality.
Boundary plasma modelling for ITER
Braams, B.J.
1993-01-01
Computer programs were developed to model the effect of nonaxisymmetric magnetic perturbations upon divertor heat load, and have explored what kind of externally applied perturbations are the most effective for heat load reduction without destroying core plasma confinement. We find that a carefully tuned set of coils located about 0.3 m outside the separatrix can be used to spread the heat load over about 0.1 m perpendicular to flux surfaces at the ITER divertor plate, even at a very low level of anomalous cross-field heat transport. As such a spreading would significantly extend the permissible regime of operation for ITER, we recommend that this study be pursued at the level of detail required for engineering design. In other work under this grant we are in the process of modifying the B2 code to handle correctly a non-orthogonal geometry.
Bioinspired Iterative Synthesis of Polyketides
NASA Astrophysics Data System (ADS)
Hong, Ran; Zheng, Kuan; Xie, Changmin
2015-05-01
Diverse array of biopolymers and second metabolites (particularly polyketide natural products) has been manufactured in nature through an enzymatic iterative assembly of simple building blocks. Inspired by this strategy, molecules with inherent modularity can be efficiently synthesized by repeated succession of similar reaction sequences. This privileged strategy has been widely adopted in synthetic supramolecular chemistry. Its value also has been reorganized in natural product synthesis. A brief overview of this approach is given with a particular emphasis on the total synthesis of polyol-embedded polyketides, a class of vastly diverse structures and biologically significant natural products. This viewpoint also illustrates the limits of known individual modules in terms of diastereoselectivity and enantioselectivity. More efficient and practical iterative strategies are anticipated to emerge in the future development.
Bioinspired iterative synthesis of polyketides
Zheng, Kuan; Xie, Changmin; Hong, Ran
2015-01-01
Diverse array of biopolymers and second metabolites (particularly polyketide natural products) has been manufactured in nature through an enzymatic iterative assembly of simple building blocks. Inspired by this strategy, molecules with inherent modularity can be efficiently synthesized by repeated succession of similar reaction sequences. This privileged strategy has been widely adopted in synthetic supramolecular chemistry. Its value also has been reorganized in natural product synthesis. A brief overview of this approach is given with a particular emphasis on the total synthesis of polyol-embedded polyketides, a class of vastly diverse structures and biologically significant natural products. This viewpoint also illustrates the limits of known individual modules in terms of diastereoselectivity and enantioselectivity. More efficient and practical iterative strategies are anticipated to emerge in the future development. PMID:26052510
Interaction of the intrinsically unstructured phage lambda N Protein with Escherichia coli NusA.
Prasch, Stefan; Schwarz, Sabine; Eisenmann, Anke; Wöhrl, Birgitta M; Schweimer, Kristian; Rösch, Paul
2006-04-11
N protein of the Escherichia coli phage lambda (lambdaN) is involved in antitermination, a transcription regulatory process that is essential for the expression of delayed early genes during phage lytic development. lambdaN is an intrinsically unstructured protein that possesses three distinct binding sites interacting with the carboxy terminus of the E. coli host factor protein NusA, the viral nutBoxB-RNA, and RNA polymerase, respectively. Heteronuclear NMR experiments with lambdaN(1-53) in complex with NusA(339-495) revealed that upon complex formation the lambdaN-binding interface, lambdaN(34-47), adopts a rigid structure. NMR data also indicate the induction of a weak helical structure in the nutboxB RNA-binding region lambdaN(1-22) upon binding to NusA(339-495) even in the absence of RNA. Titration experiments of the lambdaN(1-53)-nutBoxB RNA complex with NusA(339-495) revealed that the ternary complex can be described in terms of two structurally independent binary interactions. Furthermore, chemical-shift perturbation experiments with different NusA constructs and different lambdaN peptides showed that only NusA(353-416) is involved in lambdaN binding. We found that only one molecule of NusA(339-426) binds to one molecule of lambdaN(1-53). We also clarified the role of the lambdaN-binding region and could show that N41-R47 also binds to NusA(339-495). Furthermore, we observe that lambdaN(1-22) adopts a helical fold upon binding to NusA(339-495), in agreement with one of the theoretical models of lambdaN action.
Roles for lambda Orf and Escherichia coli RecO, RecR and RecF in lambda recombination.
Sawitzke, J A; Stahl, F W
1997-10-01
Bacteriophage lambda lacking its Red recombination functions requires either its own gene product, Orf, or the product of Escherichia coli's recO, recR and recF genes (RecORF) for efficient recombination in recBC sbcB sbcC mutant cells (the RecF pathway). Phage crosses under conditions of a partial block to DNA replication have revealed the following: (1) In the presence of Orf, RecF pathway recombination is similar to lambda Red recombination; (2) Orf is necessary for focusing recombination toward the right end of the chromosome as lambda is conventionally drawn; (3) RecORF-mediated RecF pathway recombination is not focused toward the right end of the chromosome, which may indicate that RecORF travels along the DNA; (4) both Orf- and RecORF-mediated RecF pathway recombination are stimulated by DNA replication; and (5) low level recombination in the simultaneous absence of Orf and RecORF may occur by a break-copy mechanism that is not initiated by a double strand break. Models for the roles of Orf and RecO, RecR and RecF in recombination are presented. PMID:9335578
Utilizing Synthetic Spectra to Refine Lambda Boo Stars' UV Classification Criteria
NASA Astrophysics Data System (ADS)
Cheng, Kwang-Ping; Neff, James E.; Johnson, Dustin; Tarbell, Erik; Romo, Christopher; Steele, Patricia; Gray, Richard O.; Corbally, Christopher J.
2016-01-01
Lambda Boo-type stars are a group of late B to early F-type Population I dwarfs that show deficiencies of iron-peak elements (up to 2 dex), but their C, N, O, and S abundances are near solar. This stellar class has recently regained the spotlight because of the directly-imaged planets around a confirmed Lambda Boo star, HR 8799, and a suggested Lambda Boo star Beta Pictoris. The discovery of a giant asteroid belt around Vega, another possible Lambda Boo star, also suggests hidden planets. This possible link between Lambda Boo stars and planet-bearing stars motivates us to study Lambda Boo stars systematically. Since the peculiar nature of the prototype Lambda Bootis was first noticed in 1943, Lambda Boo candidates published in the literature have been selected using widely different criteria. The Lambda Boo label has been applied to almost any peculiar A-type stars that do not fit elsewhere. In order to determine the origin of Lambda Boo stars' unique abundance pattern and to better discriminate between theories explaining the Lambda Boo phenomenon, a consistent working definition of Lambda Boo stars is needed. We have re-evaluated all published Lambda Boo candidates and their available ultraviolet and visible spectra. Using observed and synthetic spectra, we explored the classification of Lambda Boo stars and developed quantitative criteria that discriminate metal-poor stars from bona fide Lambda Boo stars. With model spectra, we demonstrated that the (C I 1657 Angstrom)/ (Al II 1671 Angstrom) line ratio is the best single criterion to distinguish between Lambda Boo stars and metal weak stars, and that one cannot use a single C I/Al II cut-off value as a Lambda Boo classification criterion. The C I/Al II cut-off value is a function of a star's effective temperature and metallicity. Using these stricter Lambda Boo classification criteria, we concluded that neither Beta Pictoris nor Vega should be classified as Lambda Boo stars.
ITER Plasma Control System Development
NASA Astrophysics Data System (ADS)
Snipes, Joseph; ITER PCS Design Team
2015-11-01
The development of the ITER Plasma Control System (PCS) continues with the preliminary design phase for 1st plasma and early plasma operation in H/He up to Ip = 15 MA in L-mode. The design is being developed through a contract between the ITER Organization and a consortium of plasma control experts from EU and US fusion laboratories, which is expected to be completed in time for a design review at the end of 2016. This design phase concentrates on breakdown including early ECH power and magnetic control of the poloidal field null, plasma current, shape, and position. Basic kinetic control of the heating (ECH, ICH, NBI) and fueling systems is also included. Disruption prediction, mitigation, and maintaining stable operation are also included because of the high magnetic and kinetic stored energy present already for early plasma operation. Support functions for error field topology and equilibrium reconstruction are also required. All of the control functions also must be integrated into an architecture that will be capable of the required complexity of all ITER scenarios. A database is also being developed to collect and manage PCS functional requirements from operational scenarios that were defined in the Conceptual Design with links to proposed event handling strategies and control algorithms for initial basic control functions. A brief status of the PCS development will be presented together with a proposed schedule for design phases up to DT operation.
Progress on US ITER Diagnostics
NASA Astrophysics Data System (ADS)
Johnson, David; Feder, Russ
2010-11-01
There have been significant advances in the design concepts for the 8 ITER diagnostic systems being provided by the US. Concepts for integration of the diagnostics into the port plugs have also evolved. A prerequisite for the signoff of the procurement arrangements for these each diagnostic is a Conceptual Design Review organized by the ITER Organization. US experts under contract with the USIPO have been assisting the IO to prepare for these Reviews. In addition, a design team at PPPL has been working with these experts and designers from other ITER parties to package diagnostic front-ends into the 5 US plugs. Modular diagnostic shield modules are now being considered in order to simplify the interfaces between the diagnostics within each plug. Diagnostic first wall elements are envisioned to be integral with these shield modules. This simplifies the remote handling of the diagnostics and provides flexibility for future removal of one diagnostic minimally affecting others. Front-end configurations will be presented, along with lists of issues needing resolution prior to the start of preliminary design.
ibr: Iterative bias reduction multivariate smoothing
Hengartner, Nicholas W; Cornillon, Pierre-andre; Matzner - Lober, Eric
2009-01-01
Regression is a fundamental data analysis tool for relating a univariate response variable Y to a multivariate predictor X {element_of} E R{sup d} from the observations (X{sub i}, Y{sub i}), i = 1,...,n. Traditional nonparametric regression use the assumption that the regression function varies smoothly in the independent variable x to locally estimate the conditional expectation m(x) = E[Y|X = x]. The resulting vector of predicted values {cflx Y}{sub i} at the observed covariates X{sub i} is called a regression smoother, or simply a smoother, because the predicted values {cflx Y}{sub i} are less variable than the original observations Y{sub i}. Linear smoothers are linear in the response variable Y and are operationally written as {cflx m} = X{sub {lambda}}Y, where S{sub {lambda}} is a n x n smoothing matrix. The smoothing matrix S{sub {lambda}} typically depends on a tuning parameter which we denote by {lambda}, and that governs the tradeoff between the smoothness of the estimate and the goodness-of-fit of the smoother to the data by controlling the effective size of the local neighborhood over which the responses are averaged. We parameterize the smoothing matrix such that large values of {lambda} are associated to smoothers that averages over larger neighborhood and produce very smooth curves, while small {lambda} are associated to smoothers that average over smaller neighborhood to produce a more wiggly curve that wants to interpolate the data. The parameter {lambda} is the bandwidth for kernel smoother, the span size for running-mean smoother, bin smoother, and the penalty factor {lambda} for spline smoother.
Xu, Qinghua; STAR Collaboration
2006-10-01
This contribution reports on a proof-of-principle measurement of the longitudinal spin transfer D{sub LL} in inclusive {Lambda} and {Lambda} production in polarized proton-proton collisions at a center of mass energy {radical}s = 200 GeV. The data sample consists of about 3 x 10{sup 6} minimum bias events collected in the year 2005 by the STAR experiment at RHIC with proton beam polarizations of up to 50%. The {Lambda}({bar {Lambda}}) candidates are reconstructed at mid-rapidity (|{eta}| < 1) using the STAR Time Projection Chamber via the dominant decay channel {Lambda} {yields} p{pi}{sup -} ({Lambda} {yields} {bar p}{pi}{sup +}). Their mean transverse momentum p{sub T} is about 1.3 GeV/c and longitudinal momentum fraction x{sub F} = 7.5 x 10{sup -3}. The longitudinal {Lambda}({bar {Lambda}}) polarization is determined using a method in which the detector acceptance mostly cancels.
NASA Astrophysics Data System (ADS)
Cheng, Kwang-Ping; Neff, James E.; Johnson, Dustin M.; Tarbell, Erik S.; Romo, Christopher A.; Prabhaker, Arvind; Steele, Patricia A.; Gray, Richard O.; Corbally, Christopher J.
2016-04-01
Lambda Boo-type stars are a group of late B to early F-type Population I dwarfs that show mild to extreme deficiencies of iron-peak elements (up to 2 dex), but their C, N, O, and S abundances are near solar. This intriguing stellar class has recently regained the spotlight because of the directly imaged planets around a confirmed Lambda Boo star, HR 8799, and a suggested Lambda Boo star, Beta Pictoris. The discovery of a giant asteroid belt around Vega, another possible Lambda Boo star, also suggests hidden planets. The possible link between Lambda Boo stars and planet-bearing stars motivates us to study Lambda Boo stars systematically. Since the peculiar nature of the prototype Lambda Boötis was first noticed in 1943, Lambda Boo candidates published in the literature have been selected using widely different criteria. In order to determine the origin of Lambda Boo stars’ unique abundance pattern and to better discriminate between theories explaining the Lambda Boo phenomenon, a consistent working definition of Lambda Boo stars is needed. We have re-evaluated all published Lambda Boo candidates and their available ultraviolet and visible spectra. In this paper, using observed and synthetic spectra, we explore the physical basis for the classification of Lambda Boo stars, and develop quantitative criteria that discriminate metal-poor stars from bona fide Lambda Boo stars. Based on these stricter Lambda Boo classification criteria, we conclude that neither Beta Pictoris nor Vega should be classified as Lambda Boo stars.
Transport synthetic acceleration with opposing reflecting boundary conditions
Zika, M.R.; Adams, M.L.
2000-02-01
The transport synthetic acceleration (TSA) scheme is extended to problems with opposing reflecting boundary conditions. This synthetic method employs a simplified transport operator as its low-order approximation. A procedure is developed that allows the use of the conjugate gradient (CG) method to solve the resulting low-order system of equations. Several well-known transport iteration algorithms are cast in a linear algebraic form to show their equivalence to standard iterative techniques. Source iteration in the presence of opposing reflecting boundary conditions is shown to be equivalent to a (poorly) preconditioned stationary Richardson iteration, with the preconditioner defined by the method of iterating on the incident fluxes on the reflecting boundaries. The TSA method (and any synthetic method) amounts to a further preconditioning of the Richardson iteration. The presence of opposing reflecting boundary conditions requires special consideration when developing a procedure to realize the CG method for the proposed system of equations. The CG iteration may be applied only to symmetric positive definite matrices; this condition requires the algebraic elimination of the boundary angular corrections from the low-order equations. As a consequence of this elimination, evaluating the action of the resulting matrix on an arbitrary vector involves two transport sweeps and a transmission iteration. Results of applying the acceleration scheme to a simple test problem are presented.
Radioactivity measurements of ITER materials using the TFTR D-T neutron field
Kumar, A.; Abdou, M.A.; Barnes, C.W.; Kugel, H.W.; Loughlin, M.J.
1994-08-01
The availability of high D-T fusion neutron yields at TFTR has provided a useful opportunity to directly measure D-T neutron-induced radioactivity in a realistic tokamak fusion reactor environment for materials of vital interest to ITER. These measurements are valuable for characterizing radioactivity in various ITER candidate materials. for validating complex neutron transport calculations, and for meeting fusion reactor licensing requirements. The radioactivity measurements at TFTR involve potential ITER materials including stainless steel 316, vanadium, titanium, chromium, silicon, iron, cobalt, nickel, molybdenum, aluminum, copper, zinc. zirconium, niobium, and tungsten. Small samples of these materials were irradiated close to the plasma and just outside the vacuum vessel wall of TFTR, locations of different neutron energy spectra. Saturation activities for both threshold and capture reactions were measured. Data from dosimetric reactions have been used to obtain preliminary neutron energy spectra. Spectra from the first wall were compared to calculations from ITER and to measurements from accelerator-based tests.
Inhibitory effect of tocotrienol on eukaryotic DNA polymerase {lambda} and angiogenesis
Mizushina, Yoshiyuki . E-mail: mizushin@nutr.kobegakuin.ac.jp; Nakagawa, Kiyotaka; Shibata, Akira; Awata, Yasutoshi; Kuriyama, Isoko; Shimazaki, Noriko; Koiwai, Osamu; Uchiyama, Yukinobu; Sakaguchi, Kengo; Miyazawa, Teruo; Yoshida, Hiromi
2006-01-20
Tocotrienols, vitamin E compounds that have an unsaturated side chain with three double bonds, selectively inhibited the activity of mammalian DNA polymerase {lambda} (pol {lambda}) in vitro. These compounds did not influence the activities of replicative pols such as {alpha}, {delta}, and {epsilon}, or even the activity of pol {beta} which is thought to have a very similar three-dimensional structure to the pol {beta}-like region of pol {lambda}. Since {delta}-tocotrienol had the strongest inhibitory effect among the four ({alpha}- to {delta}-) tocotrienols, the isomer's structure might be an important factor in the inhibition of pol {lambda}. The inhibitory effect of {delta}-tocotrienol on both intact pol {lambda} (residues 1-575) and a truncated pol {lambda} lacking the N-terminal BRCA1 C-terminus (BRCT) domain (residues 133-575, del-1 pol {lambda}) was dose-dependent, with 50% inhibition observed at a concentration of 18.4 and 90.1 {mu}M, respectively. However, del-2 pol {lambda} (residues 245-575) containing the C-terminal pol {beta}-like region was unaffected. Tocotrienols also inhibited the proliferation of and formation of tubes by bovine aortic endothelial cells, with {delta}-tocotrienol having the greatest effect. These results indicated that tocotrienols targeted both pol {lambda} and angiogenesis as anti-cancer agents. The relationship between the inhibition of pol {lambda} and anti-angiogenesis by {delta}-tocotrienol was discussed.
Fourier mode analysis of slab-geometry transport iterations in spatially periodic media
Larsen, E W; Zika, M R
1999-05-07
We describe a Fourier analysis of the diffusion-synthetic acceleration (DSA) and transport-synthetic acceleration (TSA) iteration schemes for a spatially periodic, but otherwise arbitrarily heterogeneous, medium. Both DSA and TSA converge more slowly in a heterogeneous medium than in a homogeneous medium composed of the volume-averaged scattering ratio. In the limit of a homogeneous medium, our heterogeneous analysis contains eigenvalues of multiplicity two at ''resonant'' wave numbers. In the presence of material heterogeneities, error modes corresponding to these resonant wave numbers are ''excited'' more than other error modes. For DSA and TSA, the iteration spectral radius may occur at these resonant wave numbers, in which case the material heterogeneities most strongly affect iterative performance.
Fourier mode analysis of slab-geometry transport iterations in spatially periodic media
Larsen, E; Zika, M
1999-04-01
We describe a Fourier analysis of the diffusion-synthetic acceleration (DSA) and transport-synthetic acceleration (TSA) iteration schemes for a spatially periodic, but otherwise arbitrarily heterogeneous, medium. Both DSA and TSA converge more slowly in a heterogeneous medium than in a homogeneous medium composed of the volume-averaged scattering ratio. In the limit of a homogeneous medium, our heterogeneous analysis contains eigenvalues of multiplicity two at ''resonant'' wave numbers. In the presence of material heterogeneities, error modes corresponding to these resonant wave numbers are ''excited'' more than other error modes. For DSA and TSA, the iteration spectral radius may occur at these resonant wave numbers, in which case the material heterogeneities most strongly affect iterative performance.
Simpson, J.D.
1990-01-01
The search for new methods to accelerate particle beams to high energy using high gradients has resulted in a number of candidate schemes. One of these, wakefield acceleration, has been the subject of considerable R D in recent years. This effort has resulted in successful proof of principle experiments and in increased understanding of many of the practical aspects of the technique. Some wakefield basics plus the status of existing and proposed experimental work is discussed, along with speculations on the future of wake field acceleration. 10 refs., 6 figs.
Colgate, S.A.
1958-05-27
An improvement is presented in linear accelerators for charged particles with respect to the stable focusing of the particle beam. The improvement consists of providing a radial electric field transverse to the accelerating electric fields and angularly introducing the beam of particles in the field. The results of the foregoing is to achieve a beam which spirals about the axis of the acceleration path. The combination of the electric fields and angular motion of the particles cooperate to provide a stable and focused particle beam.
[lambda][phi][sup 4] q-renormalization program
Rodriguez-Romo, S. )
1994-03-01
A regularization scheme for quantum field theories given in q-mutator algebra for the internal momentum space in a loop integration is constructed. The author shows Feynman integrals that are finite for q [ne] 1 but diverse as q [yields] 1. Using this regularization scheme, the author proposes a renormalization program in q-mutator space (q-renormalization program) for the [lambda][phi][sup 4] theory as an example, up to some one-loop diagrams. This work paves the way to obtaining physically measureable quantities from quantum field theories over spaces that neither commute nor anticommute.
{Lambda}CDM universe in f(R) gravity
Dunsby, Peter K. S.; Elizalde, Emilio; Saez-Gomez, Diego; Goswami, Rituparno; Odintsov, Sergei
2010-07-15
Several different explicit reconstructions of f(R) gravity are obtained from the background Friedmann-Laimatre-Robertson-Walker expansion history. It is shown that the only theory whose Lagrangian is a simple function of the Ricci scalar R, that admits an exact {Lambda}CDM expansion history, is standard general relativity with a positive cosmological constant and the only way to obtain this behavior of the scale factor for more general functions of R is to add additional degrees of freedom to the matter sector.
Origin of the {lambda} Transition in Liquid Sulfur
Scopigno, T.; Yannopoulos, S. N.; Andrikopoulos, K. S.; Fioretto, D.; Ruocco, G.
2007-07-13
Developing a novel experimental technique, we applied photon correlation spectroscopy using infrared radiation in liquid sulfur around T{sub {lambda}}, i.e., in the temperature range where an abrupt increase in viscosity by 4 orders of magnitude is observed upon heating within few degrees. This allowed us--overcoming photoinduced and absorption effects at visible wavelengths--to reveal a chain relaxation process with characteristic time in the millisecond range. These results do rehabilitate the validity of the Maxwell relation in sulfur from an apparent failure, allowing rationalizing of the mechanical and thermodynamic behavior of this system within a viscoelastic scenario.
GAS CLUMPING IN THE OUTSKIRTS OF {Lambda}CDM CLUSTERS
Nagai, Daisuke; Lau, Erwin T.
2011-04-10
Recent Suzaku X-ray observations revealed that the observed entropy profile of the intracluster medium (ICM) deviates significantly from the prediction of hydrodynamical simulations of galaxy clusters. In this work, we show that gas clumping introduces significant biases in X-ray measurements of the ICM profiles in the outskirts of galaxy clusters. Using hydrodynamical simulations of galaxy cluster formation in a concordance {Lambda}CDM model, we demonstrate that gas clumping leads to an overestimate of the observed gas density and causes flattening of the entropy profile. Our results suggest that gas clumping must be taken into account when interpreting X-ray measurements of cluster outskirts.
Bell, J.S.
1959-09-15
An arrangement for the drift tubes in a linear accelerator is described whereby each drift tube acts to shield the particles from the influence of the accelerating field and focuses the particles passing through the tube. In one embodiment the drift tube is splii longitudinally into quadrants supported along the axis of the accelerator by webs from a yoke, the quadrants. webs, and yoke being of magnetic material. A magnetic focusing action is produced by energizing a winding on each web to set up a magnetic field between adjacent quadrants. In the other embodiment the quadrants are electrically insulated from each other and have opposite polarity voltages on adjacent quadrants to provide an electric focusing fleld for the particles, with the quadrants spaced sufficienily close enough to shield the particles within the tube from the accelerating electric field.
Abbin, J.P. Jr.; Devaney, H.F.; Hake, L.W.
1979-08-29
The disclosure relates to an improved integrating acceleration switch of the type having a mass suspended within a fluid filled chamber, with the motion of the mass initially opposed by a spring and subsequently not so opposed.
Abbin, Jr., Joseph P.; Devaney, Howard F.; Hake, Lewis W.
1982-08-17
The disclosure relates to an improved integrating acceleration switch of the type having a mass suspended within a fluid filled chamber, with the motion of the mass initially opposed by a spring and subsequently not so opposed.
Rater variables associated with ITER ratings.
Paget, Michael; Wu, Caren; McIlwrick, Joann; Woloschuk, Wayne; Wright, Bruce; McLaughlin, Kevin
2013-10-01
Advocates of holistic assessment consider the ITER a more authentic way to assess performance. But this assessment format is subjective and, therefore, susceptible to rater bias. Here our objective was to study the association between rater variables and ITER ratings. In this observational study our participants were clerks at the University of Calgary and preceptors who completed online ITERs between February 2008 and July 2009. Our outcome variable was global rating on the ITER (rated 1-5), and we used a generalized estimating equation model to identify variables associated with this rating. Students were rated "above expected level" or "outstanding" on 66.4 % of 1050 online ITERs completed during the study period. Two rater variables attenuated ITER ratings: the log transformed time taken to complete the ITER [β = -0.06, 95 % confidence interval (-0.10, -0.02), p = 0.002], and the number of ITERs that a preceptor completed over the time period of the study [β = -0.008 (-0.02, -0.001), p = 0.02]. In this study we found evidence of leniency bias that resulted in two thirds of students being rated above expected level of performance. This leniency bias appeared to be attenuated by delay in ITER completion, and was also blunted in preceptors who rated more students. As all biases threaten the internal validity of the assessment process, further research is needed to confirm these and other sources of rater bias in ITER ratings, and to explore ways of limiting their impact.
Rutherford, P.H.
1997-04-01
Experimental research on the International Thermonuclear Experimental Reactor (ITER) will go far beyond what is possible on present-day tokamaks to address new and challenging issues in the physics of reactor-like plasmas. First and foremost, experiments in ITER will explore the physics issues of burning plasmas--plasmas that are dominantly self-heated by alpha-particles created by the fusion reactions themselves. Such issues will include (i) new plasma-physical effects introduced by the presence within the plasma of an intense population of energetic alpha particles; (ii) the physics of magnetic confinement for a burning plasma, which will involve a complex interplay of transport, stability and an internal self-generated heat source; and (iii) the physics of very-long-pulse/steady-state burning plasmas, in which much of the plasma current is also self-generated and which will require effective control of plasma purity and plasma-wall interactions. Achieving and sustaining burning plasma regimes in a tokamak necessarily requires plasmas that are larger than those in present experiments and have higher energy content and power flow, as well as much longer pulse length. Accordingly, the experimental program on ITER will embrace the study of issues of plasma physics and plasma-materials interactions that are specific to a reactor-scale fusion experiment. Such issues will include (i) confinement physics for a tokamak in which, for the first time, the core-plasma and the edge-plasma are simultaneously in a reactor-like regime; (ii) phenomena arising during plasma transients, including so-called disruptions, in regimes of high plasma current and thermal energy; and (iii) physics of a radiative divertor designed for handling high power flow for long pulses, including novel plasma and atomic-physics effects as well as materials science of surfaces subject to intense plasma interaction. Experiments on ITER will be conducted by researchers in control rooms situated at major
Iterates of maps with symmetry
NASA Technical Reports Server (NTRS)
Chossat, Pascal; Golubitsky, Martin
1988-01-01
Fixed-point bifurcation, period doubling, and Hopf bifurcation (HB) for iterates of equivariant mappings are investigated analytically, with a focus on HB in the presence of symmetry. An algebraic formulation for the hypotheses of the theorem of Ruelle (1973) is derived, and the case of standing waves in a system of ordinary differential equations with O(2) symmetry is considered in detail. In this case, it is shown that HB can lead directly to motion on an invariant 3-torus, with an unexpected third frequency due to drift of standing waves along the torus.
Christofilos, N.C.; Polk, I.J.
1959-02-17
Improvements in linear particle accelerators are described. A drift tube system for a linear ion accelerator reduces gap capacity between adjacent drift tube ends. This is accomplished by reducing the ratio of the diameter of the drift tube to the diameter of the resonant cavity. Concentration of magnetic field intensity at the longitudinal midpoint of the external sunface of each drift tube is reduced by increasing the external drift tube diameter at the longitudinal center region.
Is cosmic acceleration slowing down?
Shafieloo, Arman; Sahni, Varun; Starobinsky, Alexei A.
2009-11-15
We investigate the course of cosmic expansion in its recent past using the Constitution SN Ia sample, along with baryon acoustic oscillations (BAO) and cosmic microwave background (CMB) data. Allowing the equation of state of dark energy (DE) to vary, we find that a coasting model of the universe (q{sub 0}=0) fits the data about as well as Lambda cold dark matter. This effect, which is most clearly seen using the recently introduced Om diagnostic, corresponds to an increase of Om and q at redshifts z < or approx. 0.3. This suggests that cosmic acceleration may have already peaked and that we are currently witnessing its slowing down. The case for evolving DE strengthens if a subsample of the Constitution set consisting of SNLS+ESSENCE+CfA SN Ia data is analyzed in combination with BAO+CMB data. The effect we observe could correspond to DE decaying into dark matter (or something else)
ASTEROSEISMOLOGICAL MODELING OF THE MULTIPERIODIC {lambda} BOOTIS STAR 29 CYGNI
Casas, R.; Moya, A.; Martin-Ruiz, S.; Amado, P. J.; Garrido, R.; Suarez, J. C.; Rodriguez-Lopez, C
2009-05-20
The present work focuses on the discussion of the {lambda} Bootis nature of the multiperiodic {delta} Scuti star HD 192640 (29 Cyg), through a comprehensive asteroseismic modeling. Some of the most recent asteroseismic tools are used to check whether the observed low metallicity is internal, i.e., intrinsic, present throughout the star, or due to superficial processes as accretion, diffusive settling, radiative levitation, mass loss, etc. The modeling method uses some of the most recent tools, including: (1) effects of rotation on equilibrium models, on the adiabatic oscillation spectrum, and its influence in multicolor observables, (2) nonadiabatic stability of radial and nonradial modes, (3) inclusion of the atmosphere-pulsation interaction for a more accurate multicolor mode identification, and (4) ratio between radial modes n = 4 and n = 5 in the framework of Petersen diagrams. The analysis performed reveals that the models fulfilling all the constraints are those in the middle of the main sequence (MS), with subsolar metallicity, except some other unlikely possibilities. Therefore, this study does not support the idea of the {lambda} Bootis stars being zero-age MS or pre-MS stars interacting with their primordial cloud of gas and dust, but suggest the explanation of their nature as submetallic MS objects. Nevertheless, more accurate multicolor photometric observations are required for a more conclusive study using the procedure presented here, since the observational errors are too large for a definitive rejection of any of the possible explanations.
Detection of single lambda DNA fragments by flow cytometry
Johnson, M.E.; Goodwin, P.M.; Ambrose, W.P.; Martin, J.C.; Marrone, B.L.; Keller, R.A. )
1993-01-01
The authors have demonstrated flow cytometric detection and sizing of single pieces of fluorescently stained lambda DNA (48.5 kb) and individual Kpn I restriction fragments of lambda DNA at 17.05 kb and 29.95 kb. DNA fragments were stained stoichiometrically with an intercalating dye such that the fluorescence from each fragment was directly proportional to fragment length. Laser powers range from 10 to 100 mW and transit times through the focused laser beam were several milliseconds. Measurements were made using time-resolved single photon counting of the detected fluorescence emission from individual stained DNA fragments. Samples were analyzed at rates of about 50 fragments per second. The measured fluorescence intensities are linearly correlated with DNA fragment length over the range measured. Detection sensitivity and resolution needed for analysis of small pieces of DNA are discussed and a comparison of single photon counting measurements of DNA fragments to measurements using more conventional flow cytometers is made. Applications of this methodology to DNA sizing and DNA fingerprinting are discussed.
An Effective CUDA Parallelization of Projection in Iterative Tomography Reconstruction.
Xie, Lizhe; Hu, Yining; Yan, Bin; Wang, Lin; Yang, Benqiang; Liu, Wenyuan; Zhang, Libo; Luo, Limin; Shu, Huazhong; Chen, Yang
2015-01-01
Projection and back-projection are the most computationally intensive parts in Computed Tomography (CT) reconstruction, and are essential to acceleration of CT reconstruction algorithms. Compared to back-projection, parallelization efficiency in projection is highly limited by racing condition and thread unsynchronization. In this paper, a strategy of Fixed Sampling Number Projection (FSNP) is proposed to ensure the operation synchronization in the ray-driven projection with Graphical Processing Unit (GPU). Texture fetching is also used utilized to further accelerate the interpolations in both projection and back-projection. We validate the performance of this FSNP approach using both simulated and real cone-beam CT data. Experimental results show that compare to the conventional approach, the proposed FSNP method together with texture fetching is 10~16 times faster than the conventional approach based on global memory, and thus leads to more efficient iterative algorithm in CT reconstruction.
Spectroscopic study of the Lambda hypernuclei by the (e,e'K+) reaction
Toshinobu Miyoshi
2003-03-31
Hypernuclear spectroscopy study via the (e,e'K+) reaction has been carried out for the first time, establishing a new technique to study Lambda hypernuclei. The high quality electron beam at Jefferson Lab made it possible to measure Lambda hypernuclear spectra with an energy resolution better than 1 MeV (FWHM). The present experiment was designed to make full use of the virtual photon flux, which peaks at very forward angles, by detecting scattered electrons at 0 degrees. Scattered positive kaons were also detected near 0 degrees, where the cross section of the kaon photo-production is maximized. This unique kinematical configuration was realized with the HyperNuclear Spectrometer System (HNSS), which consisted of the Short-Orbit Spectrometer, the Enge Split-Pole Spectrometer, and the splitter magnet. The Lambda12B mass spectrum was measured in the 12C(e,e'K+)Lambda12B reaction with 0.9 MeV (FWHM) energy resolution. The averaged binding energy of the Lambda12B ground state doublet was obtained to be 11.7 ± 0.1 (statistical) ± 0.3 (systematic) MeV, which is consistent with emulsion data. The general spectral structure of the 12C(e,e'K+) Lambda12B reaction was found to be similar to that of the 12C(Lambda+,K+)Lambda12C reaction, showing characteristic peaks corresponding to sLambda and pLambda orbits, as well as a few core-excited states. The cross section of the Lambda12B ground state doublet was derived to be 117 ± 13 (statistical) ± 14 (systematic) nb/sr. The theoretical prediction of the cross section was consistent with the present result, validating DWIA calculation for hypernuclear yields. The present study proved the effectiveness of the (e,e'K+) reaction for future Lambda hypernuclear spectroscopy studies.
Deterministic photon-photon {radical}(SWAP)gate using a {Lambda} system
Koshino, Kazuki; Ishizaka, Satoshi; Nakamura, Yasunobu
2010-07-15
We theoretically present a method to realize a deterministic photon-photon {radical}(SWAP) gate using a three-level {Lambda} system interacting with single photons in reflection geometry. The {Lambda} system is used completely passively as a temporary memory for a photonic qubit; the initial state of the {Lambda} system may be arbitrary, and active control by auxiliary fields is unnecessary throughout the gate operations. These distinct merits make this entangling gate suitable for deterministic and scalable quantum computation.
ON THE COMPLETENESS AND QUASIPOWER BASIS PROPERTY OF SYSTEMS \\{z^nf(\\lambda_nz)\\}
NASA Astrophysics Data System (ADS)
Oskolkov, V. A.
1990-02-01
This paper discusses questions of completeness and the quasipower property in spaces A_R of systems of functions \\{z^nf(\\lambda_nz)\\} under some natural conditions on the Taylor coefficients of the function f(z), assumed regular in a disk \\vert z\\vert. The complex numbers \\lambda_n ( n=0,1,\\dots) are subject to the condition \\vert\\lambda_n\\vert\\leqslant1. Bibliography: 8 titles.
Characteristics of an electron-beam rocket pellet accelerator
Tsai, C.C.; Foster, C.A.; Schechter, D.E.
1989-01-01
An electron-beam rocket pellet accelerator has been designed, built, assembled, and tested as a proof-of-principle (POP) apparatus. The main goal of accelerators based on this concept is to use intense electron-beam heating and ablation of a hydrogen propellant stick to accelerate deuterium and/or tritium pellets to ultrahigh speeds (10 to 20 km/s) for plasma fueling of next-generation fusion devices such as the International Thermonuclear Engineering Reactor (ITER). The POP apparatus is described and initial results of pellet acceleration experiments are presented. Conceptual ultrahigh-speed pellet accelerators are discussed. 14 refs., 8 figs.
A Parallel Iterative Method for Computing Molecular Absorption Spectra.
Koval, Peter; Foerster, Dietrich; Coulaud, Olivier
2010-09-14
We describe a fast parallel iterative method for computing molecular absorption spectra within TDDFT linear response and using the LCAO method. We use a local basis of "dominant products" to parametrize the space of orbital products that occur in the LCAO approach. In this basis, the dynamic polarizability is computed iteratively within an appropriate Krylov subspace. The iterative procedure uses a matrix-free GMRES method to determine the (interacting) density response. The resulting code is about 1 order of magnitude faster than our previous full-matrix method. This acceleration makes the speed of our TDDFT code comparable with codes based on Casida's equation. The implementation of our method uses hybrid MPI and OpenMP parallelization in which load balancing and memory access are optimized. To validate our approach and to establish benchmarks, we compute spectra of large molecules on various types of parallel machines. The methods developed here are fairly general, and we believe they will find useful applications in molecular physics/chemistry, even for problems that are beyond TDDFT, such as organic semiconductors, particularly in photovoltaics.
Iterative Beam Hardening Correction for Multi-Material Objects.
Zhao, Yunsong; Li, Mengfei
2015-01-01
In this paper, we propose an iterative beam hardening correction method that is applicable for the case with multiple materials. By assuming that the materials composing scanned object are known and that they are distinguishable by their linear attenuation coefficients at some given energy, the beam hardening correction problem is converted into a nonlinear system problem, which is then solved iteratively. The reconstructed image is the distribution of linear attenuation coefficient of the scanned object at a given energy. So there are no beam hardening artifacts in the image theoretically. The proposed iterative scheme combines an accurate polychromatic forward projection with a linearized backprojection. Both forward projection and backprojection have high degree of parallelism, and are suitable for acceleration on parallel systems. Numerical experiments with both simulated data and real data verifies the validity of the proposed method. The beam hardening artifacts are alleviated effectively. In addition, the proposed method has a good tolerance on the error of the estimated x-ray spectrum.
Improved criticality convergence via a modified Monte Carlo iteration method
Booth, Thomas E; Gubernatis, James E
2009-01-01
Nuclear criticality calculations with Monte Carlo codes are normally done using a power iteration method to obtain the dominant eigenfunction and eigenvalue. In the last few years it has been shown that the power iteration method can be modified to obtain the first two eigenfunctions. This modified power iteration method directly subtracts out the second eigenfunction and thus only powers out the third and higher eigenfunctions. The result is a convergence rate to the dominant eigenfunction being |k{sub 3}|/k{sub 1} instead of |k{sub 2}|/k{sub 1}. One difficulty is that the second eigenfunction contains particles of both positive and negative weights that must sum somehow to maintain the second eigenfunction. Summing negative and positive weights can be done using point detector mechanics, but this sometimes can be quite slow. We show that an approximate cancellation scheme is sufficient to accelerate the convergence to the dominant eigenfunction. A second difficulty is that for some problems the Monte Carlo implementation of the modified power method has some stability problems. We also show that a simple method deals with this in an effective, but ad hoc manner.
Barr, W.L.; Bathke, C.G.; Brooks, J.N.; Bulmer, R.H.; Busigin, A.; DuBois, P.F.; Fenstermacher, M.E.; Fink, J.; Finn, P.A.; Galambos, J.D.; Gohar, Y.; Gorker, G.E.; Haines, J.R.; Hassanein, A.M.; Hicks, D.R.; Ho, S.K.; Kalsi, S.S.; Kalyanam, K.M.; Kerns, J.A.; Lee, J.D.; Miller, J.R.; Miller, R.L.; Myall, J.O.; Peng, Y-K.M.; Perkins, L.J.; Spampinato, P.T.; Strickler, D.J.; Thomson, S.L.; Wagner, C.E.; Willms, R.S.; Reid, R.L.
1988-04-01
A tokamak systems code capable of modeling experimental test reactors has been developed and is described in this document. The code, named TETRA (for Tokamak Engineering Test Reactor Analysis), consists of a series of modules, each describing a tokamak system or component, controlled by an optimizer/driver. This code development was a national effort in that the modules were contributed by members of the fusion community and integrated into a code by the Fusion Engineering Design Center. The code has been checked out on the Cray computers at the National Magnetic Fusion Energy Computing Center and has satisfactorily simulated the Tokamak Ignition/Burn Experimental Reactor II (TIBER) design. A feature of this code is the ability to perform optimization studies through the use of a numerical software package, which iterates prescribed variables to satisfy a set of prescribed equations or constraints. This code will be used to perform sensitivity studies for the proposed International Thermonuclear Experimental Reactor (ITER). 22 figs., 29 tabs.
ITER Port Interspace Pressure Calculations
Carbajo, Juan J; Van Hove, Walter A
2016-01-01
The ITER Vacuum Vessel (VV) is equipped with 54 access ports. Each of these ports has an opening in the bioshield that communicates with a dedicated port cell. During Tokamak operation, the bioshield opening must be closed with a concrete plug to shield the radiation coming from the plasma. This port plug separates the port cell into a Port Interspace (between VV closure lid and Port Plug) on the inner side and the Port Cell on the outer side. This paper presents calculations of pressures and temperatures in the ITER (Ref. 1) Port Interspace after a double-ended guillotine break (DEGB) of a pipe of the Tokamak Cooling Water System (TCWS) with high temperature water. It is assumed that this DEGB occurs during the worst possible conditions, which are during water baking operation, with water at a temperature of 523 K (250 C) and at a pressure of 4.4 MPa. These conditions are more severe than during normal Tokamak operation, with the water at 398 K (125 C) and 2 MPa. Two computer codes are employed in these calculations: RELAP5-3D Version 4.2.1 (Ref. 2) to calculate the blowdown releases from the pipe break, and MELCOR, Version 1.8.6 (Ref. 3) to calculate the pressures and temperatures in the Port Interspace. A sensitivity study has been performed to optimize some flow areas.
Iterated Stretching of Viscoelastic Jets
NASA Technical Reports Server (NTRS)
Chang, Hsueh-Chia; Demekhin, Evgeny A.; Kalaidin, Evgeny
1999-01-01
We examine, with asymptotic analysis and numerical simulation, the iterated stretching dynamics of FENE and Oldroyd-B jets of initial radius r(sub 0), shear viscosity nu, Weissenberg number We, retardation number S, and capillary number Ca. The usual Rayleigh instability stretches the local uniaxial extensional flow region near a minimum in jet radius into a primary filament of radius [Ca(1 - S)/ We](sup 1/2)r(sub 0) between two beads. The strain-rate within the filament remains constant while its radius (elastic stress) decreases (increases) exponentially in time with a long elastic relaxation time 3We(r(sup 2, sub 0)/nu). Instabilities convected from the bead relieve the tension at the necks during this slow elastic drainage and trigger a filament recoil. Secondary filaments then form at the necks from the resulting stretching. This iterated stretching is predicted to occur successively to generate high-generation filaments of radius r(sub n), (r(sub n)/r(sub 0)) = square root of 2[r(sub n-1)/r(sub 0)](sup 3/2) until finite-extensibility effects set in.
Experimental Evidence on Iterated Reasoning in Games
Grehl, Sascha; Tutić, Andreas
2015-01-01
We present experimental evidence on two forms of iterated reasoning in games, i.e. backward induction and interactive knowledge. Besides reliable estimates of the cognitive skills of the subjects, our design allows us to disentangle two possible explanations for the observed limits in performed iterated reasoning: Restrictions in subjects’ cognitive abilities and their beliefs concerning the rationality of co-players. In comparison to previous literature, our estimates regarding subjects’ skills in iterated reasoning are quite pessimistic. Also, we find that beliefs concerning the rationality of co-players are completely irrelevant in explaining the observed limited amount of iterated reasoning in the dirty faces game. In addition, it is demonstrated that skills in backward induction are a solid predictor for skills in iterated knowledge, which points to some generalized ability of the subjects in iterated reasoning. PMID:26312486
Experimental Constraints on the Spin and Parity of the {lambda}{sub c}(2880){sup +}
Mizuk, R.; Balagura, V.; Chistov, R.; Danilov, M.; Liventsev, D.; Pakhlov, P.; Pakhlova, G.; Tikhomirov, I.; Uglov, T.; Abe, K.; Adachi, I.; Gershon, T.; Haba, J.; Hazumi, M.; Itoh, R.; Iwasaki, Y.; Katayama, N.; Kichimi, H.; Krokovny, P.; Nakao, M.
2007-06-29
We report the results of several studies of the {lambda}{sub c}{sup +}{pi}{sup +}{pi}{sup -}X final state in continuum e{sup +}e{sup -} annihilation data collected by the Belle detector. An analysis of angular distributions in {lambda}{sub c}(2880){sup +}{yields}{sigma}{sub c}(2455){sup 0,++}{pi}{sup +,-} decays strongly favors a {lambda}{sub c}(2880){sup +} spin assignment of (5/2) over (3/2) or (1/2). We find evidence for {lambda}{sub c}(2880){sup +}{yields}{sigma}{sub c}(2520){sup 0,++}{pi}{sup +,-} decay and measure the ratio of {lambda}{sub c}(2880){sup +} partial widths {gamma}({sigma}{sub c}(2520){pi})/{gamma}({sigma}{sub c}(2455){pi})=0.225{+-}0.062{+-}0.= 025. This value favors the {lambda}{sub c}(2880){sup +} spin-parity assignment of (5/2){sup +} over (5/2){sup -}. We also report the first observation of {lambda}{sub c}(2940){sup +}{yields}{sigma}{sub c}(2455){sup 0,++}{pi}{sup +,-} decay and measure {lambda}{sub c}(2880){sup +} and {lambda}{sub c}(2940){sup +} mass and width parameters. These studies are based on a 553 fb{sup -1} data sample collected at or near the {upsilon}(4S) resonance at the KEKB collider.
Beta-sitosterol-3-O-beta-D-glucopyranoside: a eukaryotic DNA polymerase lambda inhibitor.
Mizushina, Yoshiyuki; Nakanishi, Rumi; Kuriyama, Isoko; Kamiya, Kohei; Satake, Toshiko; Shimazaki, Noriko; Koiwai, Osamu; Uchiyama, Yukinobu; Yonezawa, Yuko; Takemura, Masaharu; Sakaguchi, Kengo; Yoshida, Hiromi
2006-05-01
Beta-sitosterol-3-O-beta-D-glucopyranoside (compound 1), a steroidal glycoside isolated from onion (Allium cepa L.) selectively inhibited the activity of mammalian DNA polymerase lambda (pol lambda) in vitro. The compound did not influence the activities of replicative DNA polymerases such as alpha, delta and epsilon, but also showed no effect even on the activity of pol beta which is thought to have a very similar three-dimensional structure to the pol beta-like region of pol lambda. Since parts of compound 1 such as beta-sitosterol (compound 2) and D-glucose (compound 3) did not influence the activities of any enzymes tested, the converted structure of compounds 2 and 3 might be important for pol lambda inhibition. The inhibitory effect of compound 1 on both intact pol lambda (i.e. residues 1-575) and a truncated pol lambda lacking the N-terminal BRCA1 C-terminus (BRCT) domain (133-575, del-1 pol lambda) was dose-dependent, and 50% inhibition was observed at a concentration of 9.1 and 5.4 microM, respectively. The compound 1-induced inhibition of del-1 pol lambda activity was non-competitive with respect to both the DNA template-primer and the dNTP substrate. On the basis of these results, the pol lambda inhibitory mechanism of compound 1 is discussed. PMID:16621516
Preconditioned iterations to calculate extreme eigenvalues
Brand, C.W.; Petrova, S.
1994-12-31
Common iterative algorithms to calculate a few extreme eigenvalues of a large, sparse matrix are Lanczos methods or power iterations. They converge at a rate proportional to the separation of the extreme eigenvalues from the rest of the spectrum. Appropriate preconditioning improves the separation of the eigenvalues. Davidson`s method and its generalizations exploit this fact. The authors examine a preconditioned iteration that resembles a truncated version of Davidson`s method with a different preconditioning strategy.
Aaltonen, T.; Adelman, J.; Alvarez Gonzalez, B.; Amerio, S.; Amidei, D.; Anastassov, A.; Annovi, A.; Antos, J.; Apollinari, G.; Apresyan, A.; Arisawa, T.; /Waseda U. /Dubna, JINR
2009-12-01
We report a measurement of the lifetime of the {Lambda}{sub b}{sup 0} baryon in decays to the {Lambda}{sub c}{sup +} {pi}{sup -} final state in a sample corresponding to 1.1 fb{sup -1} collected in p{bar p} collisions at {radical}s = 1.96 TeV by the CDF II detector at the Tevatron collider. Using a sample of about 3000 fully reconstructed {Lambda}{sub b}{sup 0} events we measure {tau}({Lambda}{sub b}{sup 0}) = 1.401 {+-} 0.046 (stat) {+-} 0.035 (syst) ps (corresponding to c{tau}({Lambda}{sub b}{sup 0}) = 420.1 {+-} 13.7 (stat) {+-} 10.6 (syst) {micro}m, where c is the speed of light). The ratio of this result and the world average B{sup 0} lifetime yields {tau}({Lambda}{sub b}{sup 0})/{tau}(B{sup 0}) = 0.918 {+-} 0.038 (stat and syst), in good agreement with recent theoretical predictions.
New Kinematical Constraints on Cosmic Acceleration
Rapetti, David; Allen, Steve W.; Amin, Mustafa A.; Blandford, Roger; /-KIPAC, Menlo Park
2007-05-25
We present and employ a new kinematical approach to ''dark energy'' studies. We construct models in terms of the dimensionless second and third derivatives of the scale factor a(t) with respect to cosmic time t, namely the present-day value of the deceleration parameter q{sub 0} and the cosmic jerk parameter, j(t). An elegant feature of this parameterization is that all {Lambda}CDM models have j(t)=1 (constant), which facilitates simple tests for departures from the {Lambda}CDM paradigm. Applying our model to redshift-independent distance measurements, from type Ia supernovae and X-ray cluster gas mass fraction measurements, we obtain clear statistical evidence for a late time transition from a decelerating to an accelerating phase. For a flat model with constant jerk, j(t)=j, we measure q{sub 0}=-0.81 {+-} 0.14 and j=2.16 +0.81 -0.75, results that are consistent with {Lambda}CDM at about the 1{sigma} confidence level. In comparison to dynamical analyses, the kinematical approach uses a different model set and employs a minimum of prior information, being independent of any particular gravity theory. The results obtained with this new approach therefore provide important additional information and we argue that both kinematical and dynamical techniques should be employed in future dark energy studies, where possible.
Apparatus for neutralization of accelerated ions
Fink, Joel H.; Frank, Alan M.
1979-01-01
Apparatus for neutralization of a beam of accelerated ions, such as hydrogen negative ions (H.sup.-), using relatively efficient strip diode lasers which emit monochromatically at an appropriate wavelength (.lambda. = 8000 A for H.sup.- ions) to strip the excess electrons by photodetachment. A cavity, formed by two or more reflectors spaced apart, causes the laser beams to undergo multiple reflections within the cavity, thus increasing the efficiency and reducing the illumination required to obtain an acceptable percentage (.about. 85%) of neutralization.
Observation of new states decaying into Lambda(c)(+)Kappa(-)pi(+) and Lambda(c)(+)Kappa(0)/(s)pi(-).
Chistov, R; Abe, K; Abe, K; Adachi, I; Aihara, H; Anipko, D; Aulchenko, V; Aushev, T; Bakich, A M; Balagura, V; Barberio, E; Bay, A; Bedny, I; Belous, K; Bitenc, U; Bizjak, I; Blyth, S; Bondar, A; Bozek, A; Bracko, M; Brodzicka, J; Browder, T E; Chang, M-C; Chao, Y; Chen, A; Chen, K-F; Chen, W T; Cheon, B G; Choi, Y; Choi, Y K; Chuvikov, A; Cole, S; Dalseno, J; Danilov, M; Dash, M; Dragic, J; Drutskoy, A; Eidelman, S; Epifanov, D; Gabyshev, N; Garmash, A; Gershon, T; Go, A; Gokhroo, G; Golob, B; Gorisek, A; Ha, H; Haba, J; Hara, T; Hayasaka, K; Hayashii, H; Hazumi, M; Heffernan, D; Hokuue, T; Hoshi, Y; Hou, S; Hou, W-S; Hsiung, Y B; Iijima, T; Imoto, A; Inami, K; Ishikawa, A; Itoh, R; Iwasaki, M; Iwasaki, Y; Kang, J H; Katayama, N; Kawai, H; Kawasaki, T; Khan, H R; Kichimi, H; Kim, H J; Kim, H O; Kinoshita, K; Korpar, S; Krizan, P; Krokovny, P; Kumar, R; Kuo, C C; Kuzmin, A; Kwon, Y-J; Leder, G; Lee, J; Lesiak, T; Lin, S-W; Liventsev, D; Mandl, F; Marlow, D; Matsumoto, T; Matyja, A; McOnie, S; Mitaroff, W; Miyabayashi, K; Miyake, H; Miyata, H; Miyazaki, Y; Mizuk, R; Moloney, G R; Nagamine, T; Nakano, E; Nakao, M; Nishida, S; Nitoh, O; Nozaki, T; Ogawa, S; Ohshima, T; Okabe, T; Okuno, S; Olsen, S L; Onuki, Y; Ozaki, H; Pakhlov, P; Pakhlova, G; Palka, H; Park, H; Park, K S; Pestotnik, R; Piilonen, L E; Sakai, Y; Schietinger, T; Schneider, O; Schwartz, A J; Seidl, R; Sevior, M E; Shapkin, M; Shibuya, H; Shwartz, B; Sidorov, V; Singh, J B; Sokolov, A; Somov, A; Soni, N; Stanic, S; Staric, M; Stoeck, H; Sumiyoshi, T; Suzuki, S; Takasaki, F; Tamura, N; Tanaka, M; Taylor, G N; Teramoto, Y; Tian, X C; Tikhomirov, I; Tsuboyama, T; Tsukamoto, T; Uehara, S; Uglov, T; Ueno, K; Uno, S; Usov, Y; Varner, G; Villa, S; Wang, C C; Wang, C H; Wang, M-Z; Watanabe, Y; Won, E; Wu, C-H; Xie, Q L; Yabsley, B D; Yamaguchi, A; Yamashita, Y; Yamauchi, M; Zhang, L M; Zhang, Z P
2006-10-20
We report the first observation of two charmed strange baryons that decay into Lambda(c)(+)Kappa(-)pi(+). The broader of the two states is measured to have a mass of 2978.5+/-2.1+/-2.0 MeV/c2 and a width of 43.5+/-7.5+/-7.0 MeV/c2. The mass and width of the narrow state are measured to be 3076.7+/-0.9+/-0.5 MeV/c;{2} and 6.2+/-1.2+/-0.8 MeV/c2, respectively. We also perform a search for the isospin partner states that decay into Lambda(c)(+)Kappa(0)/(s)pi(-) and observe a significant signal at the mass of 3082.8+/-1.8+/-1.5 MeV/c2. The data used for this analysis were accumulated at or near the Upsilon(4S) resonance, using the Belle detector at the e+ e- asymmetric-energy collider KEKB. The integrated luminosity of the data sample used is 461.5 fb(-1). PMID:17155385
Pawel Ambrozewicz; Daniel Carman; Rob Feuerbach; Mac Mestayer; Brian Raue; Reinhard Schumacher; Avtandil Tkabladze
2006-11-19
We report measurements of the exclusive electroproduction of K{sup +}{Lambda} and K{sup +}{Sigma}{sup 0} final states from a proton target using the CLAS detector at the Thomas Jefferson National Accelerator Facility. The separated structure functions {sigma}{sub T}, {sigma}{sub L},{sigma}{sub TT}, and {sigma}{sub LT} were extracted from the {Phi}- and {epsilon}-dependent differential cross sections taken with electron beam energies of 2.567, 4.056, and 4.247 GeV. This analysis represents the first {sigma}{sub L}/{sigma}{sub T} separation with the CLAS detector, and the first measurement of the kaon electroproduction structure functions away from parallel kinematics. The data span a broad range of momentum transfers from 0.5 {le} Q{sup 2} {le} 2.8 GeV{sup 2} and invariant energy from 1.6 {le} W {le} 2.4 GeV, while spanning nearly the full center-of-mass angular range of the kaon. The separated structure functions reveal clear differences between the production dynamics for the {Lambda} and {Sigma}{sup 0} hyperons. These results provide an unprecedented data sample with which to constrain current and future models for the associated production of strangeness, which will allow for a better understanding of the underlying resonant and non-resonant contributions to hyperon production.
Research at ITER towards DEMO: Specific reactor diagnostic studies to be carried out on ITER
Krasilnikov, A. V.; Kaschuck, Y. A.; Vershkov, V. A.; Petrov, A. A.; Petrov, V. G.; Tugarinov, S. N.
2014-08-21
In ITER diagnostics will operate in the very hard radiation environment of fusion reactor. Extensive technology studies are carried out during development of the ITER diagnostics and procedures of their calibration and remote handling. Results of these studies and practical application of the developed diagnostics on ITER will provide the direct input to DEMO diagnostic development. The list of DEMO measurement requirements and diagnostics will be determined during ITER experiments on the bases of ITER plasma physics results and success of particular diagnostic application in reactor-like ITER plasma. Majority of ITER diagnostic already passed the conceptual design phase and represent the state of the art in fusion plasma diagnostic development. The number of related to DEMO results of ITER diagnostic studies such as design and prototype manufacture of: neutron and γ–ray diagnostics, neutral particle analyzers, optical spectroscopy including first mirror protection and cleaning technics, reflectometry, refractometry, tritium retention measurements etc. are discussed.
Research at ITER towards DEMO: Specific reactor diagnostic studies to be carried out on ITER
NASA Astrophysics Data System (ADS)
Krasilnikov, A. V.; Kaschuck, Y. A.; Vershkov, V. A.; Petrov, A. A.; Petrov, V. G.; Tugarinov, S. N.
2014-08-01
In ITER diagnostics will operate in the very hard radiation environment of fusion reactor. Extensive technology studies are carried out during development of the ITER diagnostics and procedures of their calibration and remote handling. Results of these studies and practical application of the developed diagnostics on ITER will provide the direct input to DEMO diagnostic development. The list of DEMO measurement requirements and diagnostics will be determined during ITER experiments on the bases of ITER plasma physics results and success of particular diagnostic application in reactor-like ITER plasma. Majority of ITER diagnostic already passed the conceptual design phase and represent the state of the art in fusion plasma diagnostic development. The number of related to DEMO results of ITER diagnostic studies such as design and prototype manufacture of: neutron and γ-ray diagnostics, neutral particle analyzers, optical spectroscopy including first mirror protection and cleaning technics, reflectometry, refractometry, tritium retention measurements etc. are discussed.
First Measurement of Transferred Polarization in the Exclusive e p --> e' K+ Lambda Reaction
Daniel S. Carman; Et. Al.
2003-04-04
The first measurements of the transferred polarization for the exclusive {rvec e}p {yields} e{prime}K{sup +}{rvec {Lambda}} reaction have been performed in Hall B at the Thomas Jefferson National Accelerator Facility using the CLAS spectrometer. A 2.567 GeV electron beam was used to measure the hyperon polarization over a range of Q{sup 2} from 0.3 to 1.5 (GeV/c){sup 2}, W from 1.6 to 2.15 GeV, and over the full center-of-mass angular range of the K{sup +} meson. Comparison with predictions of hadrodynamic models indicates strong sensitivity to the underlying resonance contributions. A non-relativistic quark model interpretation of our data suggests that the s{bar s} quark pair is produced with spins predominantly anti-aligned. Implications for the validity of the widely used {sup 3}P{sub o} quark-pair creation operator are discussed.
BULLET CLUSTER: A CHALLENGE TO {Lambda}CDM COSMOLOGY
Lee, Jounghun; Komatsu, Eiichiro
2010-07-20
To quantify how rare the bullet-cluster-like high-velocity merging systems are in the standard {Lambda} cold dark matter (CDM) cosmology, we use a large-volume (27 h {sup -3} Gpc{sup 3}) cosmological N-body MICE simulation to calculate the distribution of infall velocities of subclusters around massive main clusters. The infall velocity distribution is given at (1-3)R{sub 200} of the main cluster (where R{sub 200} is similar to the virial radius), and thus it gives the distribution of realistic initial velocities of subclusters just before collision. These velocities can be compared with the initial velocities used by the non-cosmological hydrodynamical simulations of 1E0657-56 in the literature. The latest parameter search carried out by Mastropietro and Burkert has shown that an initial velocity of 3000 km s{sup -1} at about 2R{sub 200} is required to explain the observed shock velocity, X-ray brightness ratio of the main and subcluster, X-ray morphology of the main cluster, and displacement of the X-ray peaks from the mass peaks. We show that such a high infall velocity at 2R{sub 200} is incompatible with the prediction of a {Lambda}CDM model: the probability of finding 3000 km s{sup -1} in (2-3)R{sub 200} is between 3.3 x 10{sup -11} and 3.6 x 10{sup -9}. A lower velocity, 2000 km s{sup -1} at 2R{sub 200}, is also rare, and moreover, Mastropietro and Burkert have shown that such a low initial velocity does not reproduce the X-ray brightness ratio of the main and subcluster or morphology of the main cluster. Therefore, we conclude that the existence of 1E0657-56 is incompatible with the prediction of a {Lambda}CDM model, unless a lower infall velocity solution for 1E0657-56 with {approx}<1800 km s{sup -1} at 2R{sub 200} is found.
Friedman, D; Tomich, P; Parsons, C; Olson, E; Deans, R; Flamm, E
1981-01-01
We report the isolation of lambda altSF, a variant of Escherichia coli phage lambda that substitutes sets of genes at high frequency. Two forms of the variant phage have been studied: lambda altSF lambda, which exhibits the immunity (repressor recognition) of phage lambda, and lambda altSF22, which exhibits the immunity of Salmonella phage P22. Lysates made from single plaques of lambda altSF lambda contain 10-30% phage of the P22 form. Similarly, lysates from single plaques of lambda altSF22 contain as much as 1% phage of the lambda form. Heteroduplex analyses reveal the following features of the lambda altSF chromosomes: (i) each form has the immunity genes appropriate to its immune phenotype, (ii) the substituted segments include genes involved in regulation and replication, and (iii) the alt phages have unusual additions and substitutions of DNA not normally found associated with either immunity region. In the case of lambda altSF lambda, there is a small insertion in the region of the cI gene. Because revertants that lose this inserted DNA concomitantly lose the ability to substitute, we conclude that the insertion plays a role in the substitution process. In the case of change from lambda altSF lambda to lambda altSF22, the substituting P22 genes are derived from the E. coli host. We have identified a set of Salmonella phage P22 genes in a standard nonlysogenic strain of E. coli K-12 that is apparently carried in a silent form. The reason for this lack of expression is not obvious, because this P22 material includes structural genes and associated promoters and is potentially active. When this set of genes substitutes for the analogous set of genetic material on the genome of lambda altSF lambda, the P22 genes are expressed in a normal manner. Images PMID:6454136
Planning as an Iterative Process
NASA Technical Reports Server (NTRS)
Smith, David E.
2012-01-01
Activity planning for missions such as the Mars Exploration Rover mission presents many technical challenges, including oversubscription, consideration of time, concurrency, resources, preferences, and uncertainty. These challenges have all been addressed by the research community to varying degrees, but significant technical hurdles still remain. In addition, the integration of these capabilities into a single planning engine remains largely unaddressed. However, I argue that there is a deeper set of issues that needs to be considered namely the integration of planning into an iterative process that begins before the goals, objectives, and preferences are fully defined. This introduces a number of technical challenges for planning, including the ability to more naturally specify and utilize constraints on the planning process, the ability to generate multiple qualitatively different plans, and the ability to provide deep explanation of plans.
Fully 3D iterative scatter-corrected OSEM for HRRT PET using a GPU
NASA Astrophysics Data System (ADS)
Kim, Kyung Sang; Ye, Jong Chul
2011-08-01
Accurate scatter correction is especially important for high-resolution 3D positron emission tomographies (PETs) such as high-resolution research tomograph (HRRT) due to large scatter fraction in the data. To address this problem, a fully 3D iterative scatter-corrected ordered subset expectation maximization (OSEM) in which a 3D single scatter simulation (SSS) is alternatively performed with a 3D OSEM reconstruction was recently proposed. However, due to the computational complexity of both SSS and OSEM algorithms for a high-resolution 3D PET, it has not been widely used in practice. The main objective of this paper is, therefore, to accelerate the fully 3D iterative scatter-corrected OSEM using a graphics processing unit (GPU) and verify its performance for an HRRT. We show that to exploit the massive thread structures of the GPU, several algorithmic modifications are necessary. For SSS implementation, a sinogram-driven approach is found to be more appropriate compared to a detector-driven approach, as fast linear interpolation can be performed in the sinogram domain through the use of texture memory. Furthermore, a pixel-driven backprojector and a ray-driven projector can be significantly accelerated by assigning threads to voxels and sinograms, respectively. Using Nvidia's GPU and compute unified device architecture (CUDA), the execution time of a SSS is less than 6 s, a single iteration of OSEM with 16 subsets takes 16 s, and a single iteration of the fully 3D scatter-corrected OSEM composed of a SSS and six iterations of OSEM takes under 105 s for the HRRT geometry, which corresponds to acceleration factors of 125× and 141× for OSEM and SSS, respectively. The fully 3D iterative scatter-corrected OSEM algorithm is validated in simulations using Geant4 application for tomographic emission and in actual experiments using an HRRT.
Fully 3D iterative scatter-corrected OSEM for HRRT PET using a GPU.
Kim, Kyung Sang; Ye, Jong Chul
2011-08-01
Accurate scatter correction is especially important for high-resolution 3D positron emission tomographies (PETs) such as high-resolution research tomograph (HRRT) due to large scatter fraction in the data. To address this problem, a fully 3D iterative scatter-corrected ordered subset expectation maximization (OSEM) in which a 3D single scatter simulation (SSS) is alternatively performed with a 3D OSEM reconstruction was recently proposed. However, due to the computational complexity of both SSS and OSEM algorithms for a high-resolution 3D PET, it has not been widely used in practice. The main objective of this paper is, therefore, to accelerate the fully 3D iterative scatter-corrected OSEM using a graphics processing unit (GPU) and verify its performance for an HRRT. We show that to exploit the massive thread structures of the GPU, several algorithmic modifications are necessary. For SSS implementation, a sinogram-driven approach is found to be more appropriate compared to a detector-driven approach, as fast linear interpolation can be performed in the sinogram domain through the use of texture memory. Furthermore, a pixel-driven backprojector and a ray-driven projector can be significantly accelerated by assigning threads to voxels and sinograms, respectively. Using Nvidia's GPU and compute unified device architecture (CUDA), the execution time of a SSS is less than 6 s, a single iteration of OSEM with 16 subsets takes 16 s, and a single iteration of the fully 3D scatter-corrected OSEM composed of a SSS and six iterations of OSEM takes under 105 s for the HRRT geometry, which corresponds to acceleration factors of 125× and 141× for OSEM and SSS, respectively. The fully 3D iterative scatter-corrected OSEM algorithm is validated in simulations using Geant4 application for tomographic emission and in actual experiments using an HRRT.
Nonlinear acceleration of SN transport calculations
Fichtl, Erin D; Warsa, James S; Calef, Matthew T
2010-12-20
The use of nonlinear iterative methods, Jacobian-Free Newton-Krylov (JFNK) in particular, for solving eigenvalue problems in transport applications has recently become an active subject of research. While JFNK has been shown to be effective for k-eigenvalue problems, there are a number of input parameters that impact computational efficiency, making it difficult to implement efficiently in a production code using a single set of default parameters. We show that different selections for the forcing parameter in particular can lead to large variations in the amount of computational work for a given problem. In contrast, we present a nonlinear subspace method that sits outside and effectively accelerates nonlinear iterations of a given form and requires only a single input parameter, the subspace size. It is shown to consistently and significantly reduce the amount of computational work when applied to fixed-point iteration, and this combination of methods is shown to be more efficient than JFNK for our application.
ITER Safety Analyses with ISAS
NASA Astrophysics Data System (ADS)
Gulden, W.; Nisan, S.; Porfiri, M.-T.; Toumi, I.; de Gramont, T. Boubée
1997-06-01
Detailed analyses of accident sequences for the International Thermonuclear Experimental Reactor (ITER), from an initiating event to the environmental release of activity, have involved in the past the use of different types of computer codes in a sequential manner. Since these codes were developed at different time scales in different countries, there is no common computing structure to enable automatic data transfer from one code to the other, and no possibility exists to model or to quantify the effect of coupled physical phenomena. To solve this problem, the Integrated Safety Analysis System of codes (ISAS) is being developed, which allows users to integrate existing computer codes in a coherent manner. This approach is based on the utilization of a command language (GIBIANE) acting as a “glue” to integrate the various codes as modules of a common environment. The present version of ISAS allows comprehensive (coupled) calculations of a chain of codes such as ATHENA (thermal-hydraulic analysis of transients and accidents), INTRA (analysis of in-vessel chemical reactions, pressure built-up, and distribution of reaction products inside the vacuum vessel and adjacent rooms), and NAUA (transport of radiological species within buildings and to the environment). In the near future, the integration of S AFALY (simultaneous analysis of plasma dynamics and thermal behavior of in-vessel components) is also foreseen. The paper briefly describes the essential features of ISAS development and the associated software architecture. It gives first results of a typical ITER accident sequence, a loss of coolant accident (LOCA) in the divertor cooling loop inside the vacuum vessel, amply demonstrating ISAS capabilities.
High resolution spectroscopic study of Be10Lambda;
NASA Astrophysics Data System (ADS)
Gogami, T.; Chen, C.; Kawama, D.; Achenbach, P.; Ahmidouch, A.; Albayrak, I.; Androic, D.; Asaturyan, A.; Asaturyan, R.; Ates, O.; Baturin, P.; Badui, R.; Boeglin, W.; Bono, J.; Brash, E.; Carter, P.; Chiba, A.; Christy, E.; Danagoulian, S.; de Leo, R.; Doi, D.; Elaasar, M.; Ent, R.; Fujii, Y.; Fujita, M.; Furic, M.; Gabrielyan, M.; Gan, L.; Garibaldi, F.; Gaskell, D.; Gasparian, A.; Han, Y.; Hashimoto, O.; Horn, T.; Hu, B.; Hungerford, Ed. V.; Jones, M.; Kanda, H.; Kaneta, M.; Kato, S.; Kawai, M.; Khanal, H.; Kohl, M.; Liyanage, A.; Luo, W.; Maeda, K.; Margaryan, A.; Markowitz, P.; Maruta, T.; Matsumura, A.; Maxwell, V.; Mkrtchyan, A.; Mkrtchyan, H.; Nagao, S.; Nakamura, S. N.; Narayan, A.; Neville, C.; Niculescu, G.; Niculescu, M. I.; Nunez, A.; Nuruzzaman, Okayasu, Y.; Petkovic, T.; Pochodzalla, J.; Qiu, X.; Reinhold, J.; Rodriguez, V. M.; Samanta, C.; Sawatzky, B.; Seva, T.; Shichijo, A.; Tadevosyan, V.; Tang, L.; Taniya, N.; Tsukada, K.; Veilleux, M.; Vulcan, W.; Wesselmann, F. R.; Wood, S. A.; Yamamoto, T.; Ya, L.; Ye, Z.; Yokota, K.; Yuan, L.; Zhamkochyan, S.; Zhu, L.; Hksjlab E05-115 Collaboration
2016-03-01
Spectroscopy of a Be10Lambda; hypernucleus was carried out at JLab Hall C using the (e ,e'K+) reaction. A new magnetic spectrometer system (SPL+HES+HKS), specifically designed for high resolution hypernuclear spectroscopy, was used to obtain an energy spectrum with a resolution of ˜0.78 MeV (FWHM). The well-calibrated spectrometer system of the present experiment using p (e ,e'K+)Λ ,Σ0 reactions allowed us to determine the energy levels; and the binding energy of the ground-state peak (mixture of 1- and 2- states) was found to be BΛ=8.55 ±0.07 (stat . ) ±0.11 (sys . ) MeV. The result indicates that the ground-state energy is shallower than that of an emulsion study by about 0.5 MeV which provides valuable experimental information on the charge symmetry breaking effect in the Λ N interaction.
Spectral diagnostics of high energy emission in lambda Eri
NASA Technical Reports Server (NTRS)
Smith, Myron
1995-01-01
Multi-line observations of the optical spectrum of lambda Eri demonstrates that rapidly varying, low-velocity emissions occur in several He I lines even when H alpha shows no emission. A peculiar aspect of the He I emissions is that the ratio 5876/6678 is = 1. A theory of helium line formation generally admits two common emission mechanisms. The first is recombination/cascades, which is well known to give a ratio of greater than or equal to 3. The second is a non-LTE effect that occurs in hot (O-type) photospheres when resonance He I 584 radiation becomes transparent and drives single lines along into the emission. To accommodate a ratio of 5876/6678 = 1 may require that both processes sometimes operate at the same time, presumably in separate localities near the surface of this star.
A General Formula for Fan-Beam Lambda Tomography
Wang, Ge
2006-01-01
Lambda tomography (LT) is to reconstruct a gradient-like image of an object only from local projection data. It is potentially an important technology for medical X-ray computed tomography (CT) at a reduced radiation dose. In this paper, we prove the first general formula for exact and efficient fan-beam LT from data collected along any smooth curve based on even and odd data extensions. As a result, an LT image can be reconstructed without involving any data extension. This implies that structures outside a scanning trajectory do not affect the exact reconstruction of points inside the trajectory even if the data may be measured through the outside features. The algorithm is simulated in a collinear coordinate system. The results support our theoretical analysis. PMID:23165013
NASA Technical Reports Server (NTRS)
Vlahos, L.; Machado, M. E.; Ramaty, R.; Murphy, R. J.; Alissandrakis, C.; Bai, T.; Batchelor, D.; Benz, A. O.; Chupp, E.; Ellison, D.
1986-01-01
Data is compiled from Solar Maximum Mission and Hinothori satellites, particle detectors in several satellites, ground based instruments, and balloon flights in order to answer fundamental questions relating to: (1) the requirements for the coronal magnetic field structure in the vicinity of the energization source; (2) the height (above the photosphere) of the energization source; (3) the time of energization; (4) transistion between coronal heating and flares; (5) evidence for purely thermal, purely nonthermal and hybrid type flares; (6) the time characteristics of the energization source; (7) whether every flare accelerates protons; (8) the location of the interaction site of the ions and relativistic electrons; (9) the energy spectra for ions and relativistic electrons; (10) the relationship between particles at the Sun and interplanetary space; (11) evidence for more than one acceleration mechanism; (12) whether there is single mechanism that will accelerate particles to all energies and also heat the plasma; and (13) how fast the existing mechanisms accelerate electrons up to several MeV and ions to 1 GeV.
ERIC Educational Resources Information Center
Ford, William J.
2010-01-01
This article focuses on the accelerated associate degree program at Ivy Tech Community College (Indiana) in which low-income students will receive an associate degree in one year. The three-year pilot program is funded by a $2.3 million grant from the Lumina Foundation for Education in Indianapolis and a $270,000 grant from the Indiana Commission…
Pope, K.E.
1958-01-01
This patent relates to an improved acceleration integrator and more particularly to apparatus of this nature which is gyrostabilized. The device may be used to sense the attainment by an airborne vehicle of a predetermined velocitv or distance along a given vector path. In its broad aspects, the acceleration integrator utilizes a magnetized element rotatable driven by a synchronous motor and having a cylin drical flux gap and a restrained eddy- current drag cap deposed to move into the gap. The angular velocity imparted to the rotatable cap shaft is transmitted in a positive manner to the magnetized element through a servo feedback loop. The resultant angular velocity of tae cap is proportional to the acceleration of the housing in this manner and means may be used to measure the velocity and operate switches at a pre-set magnitude. To make the above-described dcvice sensitive to acceleration in only one direction the magnetized element forms the spinning inertia element of a free gyroscope, and the outer housing functions as a gimbal of a gyroscope.
Wang, Zhehui; Barnes, Cris W.
2002-01-01
There has been invented an apparatus for acceleration of a plasma having coaxially positioned, constant diameter, cylindrical electrodes which are modified to converge (for a positive polarity inner electrode and a negatively charged outer electrode) at the plasma output end of the annulus between the electrodes to achieve improved particle flux per unit of power.
Numerical radiative transfer with state-of-the-art iterative methods made easy
NASA Astrophysics Data System (ADS)
Lambert, Julien; Paletou, Frédéric; Josselin, Eric; Glorian, Jean-Michel
2016-01-01
This article presents an on-line tool and its accompanying software resources for the numerical solution of basic radiation transfer out of local thermodynamic equilibrium (LTE). State-of-the-art stationary iterative methods such as Accelerated Λ-iteration and Gauss-Seidel schemes, using a short characteristics-based formal solver are used. We also comment on typical numerical experiments associated to the basic non-LTE radiation problem. These resources are intended for the largest use and benefit, in support to more classical radiation transfer lectures usually given at the Master level.
Iterative methods for weighted least-squares
Bobrovnikova, E.Y.; Vavasis, S.A.
1996-12-31
A weighted least-squares problem with a very ill-conditioned weight matrix arises in many applications. Because of round-off errors, the standard conjugate gradient method for solving this system does not give the correct answer even after n iterations. In this paper we propose an iterative algorithm based on a new type of reorthogonalization that converges to the solution.
Rater Variables Associated with ITER Ratings
ERIC Educational Resources Information Center
Paget, Michael; Wu, Caren; McIlwrick, Joann; Woloschuk, Wayne; Wright, Bruce; McLaughlin, Kevin
2013-01-01
Advocates of holistic assessment consider the ITER a more authentic way to assess performance. But this assessment format is subjective and, therefore, susceptible to rater bias. Here our objective was to study the association between rater variables and ITER ratings. In this observational study our participants were clerks at the University of…
Sanchez-Lopez, J.L.; Nelson, K.D.; Engelfried, J.; Akgun, U.; Alkhazov, G.; Amaro-Reyes, J.; Atamantchouk, A.G.; Ayan, A.S.; Balatz, M.Y.; Blanco-Covarrubias, A.; Bondar, N.F.; /Ball State U. /Bogazici U. /Carnegie Mellon U. /Rio de Janeiro, CBPF /Fermilab /Serpukhov, IHEP /Beijing, Inst. High Energy Phys. /Moscow, ITEP /Heidelberg, Max Planck Inst. /Moscow State U. /St. Petersburg, INP
2007-06-01
We have measured the polarization of {Lambda}{sup 0} and {bar {Lambda}{sup 0}} inclusively produced by 610 GeV/c {Sigma}{sup -} and 525 GeV/c proton beams in the experiment SELEX during the 1996/7 fixed target run at Fermilab. The polarization was measured as a function of the {Lambda} longitudinal momentum fraction x{sub F} and transverse momentum p{sub t}. For the {Lambda}{sup 0} produced by {Sigma}{sup -} the polarization is increasing with x{sub F} , from slightly negative at x{sub F} {approx} 0 to about 15% at large x{sub F} ; it shows a non-monotonic behavior as a function of p{sub t}. For the proton beam, the {Lambda}{sup 0} polarization is negative and decreasing as a function of x{sub F} and p{sub t}. The {bar {Lambda}{sup 0}} polarization is compatible with 0 for both beam particles over the full kinematic range. The target dependence was examined but no statistically significant difference was found.
LambdaStation: Exploiting Advance Networks In Data Intensive High Energy Physics Applications
Harvey B. Newman
2009-09-11
Lambda Station software implements selective, dynamic, secure path control between local storage & analysis facilities, and high bandwidth, wide-area networks (WANs). It is intended to facilitate use of desirable, alternate wide area network paths which may only be intermittently available, or subject to policies that restrict usage to specified traffic. Lambda Station clients gain awareness of potential alternate network paths via Clarens-based web services, including path characteristics such as bandwidth and availability. If alternate path setup is requested and granted, Lambda Station will configure the local network infrastructure to properly forward designated data flows via the alternate path. A fully functional implementation of Lambda Station, capable of dynamic alternate WAN path setup and teardown, has been successfully developed. A limited Lambda Station-awareness capability within the Storage Resource Manager (SRM) product has been developed. Lambda Station has been successfully tested in a number of venues, including Super Computing 2008. LambdaStation software, developed by the Fermilab team, enables dynamic allocation of alternate network paths for high impact traffic and to forward designated flows across LAN. It negotiates with reservation and provisioning systems of WAN control planes, be it based on SONET channels, demand tunnels, or dynamic circuit networks. It creates End-To-End circuit between single hosts, computer farms or networks with predictable performance characteristics, preserving QoS if supported in LAN and WAN and tied security policy allowing only specific traffic to be forwarded or received through created path. Lambda Station project also explores Network Awareness capabilities.
Coincidence Exclusive Measurement of the Nonmesonic Weak Decay of {sub {lambda}}{sup 12}C
Kim, M. J.; Ajimura, S.; Aoki, K.; Banu, A.; Bhang, H.; Fukuda, T.; Hashimoto, O.; Hwang, J. I.; Kameoka, S.; Kang, B. H.; Kim, E. H.; Kim, J. H.; Maruta, T.; Miura, Y.; Miyake, Y.; Nagae, T.; Nakamura, M.; Nakamura, S. N.; Noumi, H.; Okada, S.
2006-07-11
We have measured the angular correlation of the pair nucleons np and nn emitted from the nonmesonic weak decay (NMWD) of {sub {lambda}}{sup 12}C produced via the ({pi}+,K+) reaction in coincidence measurement. The {lambda}p {yields} np and {lambda}n {yields} nn modes were clearly identified by measuring the back-to-back correlation of the emitted nucleon pairs which is the characteristic of two-body kinematics. From the measured nucleon pair numbers Nnn and Nnp, the ratio {gamma}n/{gamma}p of the partial decay widths {gamma}n({lambda}n {yields} nn) and {gamma}p({lambda}p {yields} np) of {sub {lambda}}{sup 12}C was extracted to be 0.51 {+-} 0.13(stat){+-}0.04(syst); this result is almost free from the ambiguity due to the nuclear final state interaction and 3-body decay process, which were inherent in the previous results. The obtained {gamma}n/{gamma}p ratio of {sub {lambda}}{sup 12}C (p-shell) is close to that of {sub {lambda}}{sup 5}He (s-shell). The results are consistent with those of recent theoretical calculations.
Hattman, Stanley
1972-01-01
The N6-methyladenine (MeAde) and 5-methylcytosine (MeC) contents in deoxyribonucleic acid (DNA) of bacteriophage lambda has been analyzed as a function of host specificity. The following facts have emerged: (i) lambda grown on strains harboring the P1 prophage contain ca. 70 more MeAde residues/DNA molecule than lambda grown either in the P1-sensitive parent, or in a P1 immune-defective lysogen which does not confer P1 modification; (ii) lambda grown on strains harboring the N-3 drug-resistance factor contain ca. 60 more MeC residues/DNA molecule than lambda grown on the parental strain lacking the factor; (iii) lambda grown in Escherichia coli B strains is devoid of MeC, whereas lambda grown in a B (N-3) host contains a high level of MeC; (iv) the MeAde content in lambda DNA is not affected by the N-3 factor. These results suggest that P1 controls an adenine-specific DNA methylase, and that the N-3 plasmid controls a cytosine-specific DNA methylase. The N-3 factor has been observed previously to direct cytosine-specific methylation of phage P22 DNA and E. coli B DNA in vivo; in vitro studies presented here demonstrate this activity. PMID:4561202
NASA Astrophysics Data System (ADS)
Ahunov, Roman R.; Kuksenko, Sergey P.; Gazizov, Talgat R.
2016-06-01
A multiple solution of linear algebraic systems with dense matrix by iterative methods is considered. To accelerate the process, the recomputing of the preconditioning matrix is used. A priory condition of the recomputing based on change of the arithmetic mean of the current solution time during the multiple solution is proposed. To confirm the effectiveness of the proposed approach, the numerical experiments using iterative methods BiCGStab and CGS for four different sets of matrices on two examples of microstrip structures are carried out. For solution of 100 linear systems the acceleration up to 1.6 times, compared to the approach without recomputing, is obtained.
Measurement of the Branching Ratio Lambda_c+ -> p pi+ pi-
Lopez-Hinojosa, Guillermo; /San Luis Potosi U.
2008-03-01
The confirmation of the Cabibbo-suppressed charm baryon decay mode {Lambda}{sub c}{sup +} {yields} p{pi}{sup +}{pi}{sup -} is reported. All data analyzed are from SELEX, a fixed target experiment at Fermilab that took data during 1996 and 1997, mainly with a 600 GeV/c {Sigma}{sup -} beam. The branching ratio of the Cabibbo-suppressed decay mode {Lambda}{sub c}{sup +} {yields} p{pi}{sup +}{pi}{sup -} relative to the Cabibbo-favored mode {Lambda}{sub c}{sup +} {yields} pK{sup -}{pi}{sup +} is measured to be: {Gamma}({Lambda}{sub c}{sup +} {yields} p{pi}{sup +}{pi}{sup -})/{Gamma}({Lambda}{sub c}{sup +} {yields} pK{sup -}{pi}{sup +}) = 0.103 {+-} 0.022.
NASA Astrophysics Data System (ADS)
Walford, Natalie Kathleen
The search for undiscovered excited states of the nucleon continues to be a focus of experiments at the Thomas Jefferson National Accelerator Facility (JLab). A large effort has been launched using the CEBAF Large Acceptance Spectrometer (CLAS) detector to provide the database, which will allow nearly model-independent partial wave analyses (PWA) to be carried out in the search for such states. Polarization observables play a crucial role in the effort, as they are essential in disentangling the contributing resonant and non-resonant amplitudes. Recent coupled-channel analyses have found strong sensitivity of the K+ + Lambda channel to several higher mass nucleon resonances. In 2010, double-polarization data were taken at JLab using circularly and linearly polarized tagged photons incident on a transversely polarized frozen spin butanol target (FROST), operated at the temperature of 30 mK. The reaction products were detected in CLAS. This work is based on the analysis of FROST data and the extraction of the T, F, T x, and Tz asymmetries of the K+ Lambda and K+ Sigma 0 final states and their comparison to predictions of recent multipole analyses. There are very few published measurements of the T asymmetry and none for the F, Tx, and Tz asymmetries for the K+ Lambda final state. The K+ Sigma0 final state has no published measurements for these asymmetries. This work is the first of its kind and will significantly broaden the world database for these reactions.
TRANSP simulations of ITER plasmas
Budny, R.V.; McCune, D.C.; Redi, M.H.; Schivell, J.; Wieland, R.M.
1995-12-01
The TRANSP code is used to construct comprehensive, self-consistent models for ITER discharges. Plasma parameters are studied for two discharges from the ITER ``Interim Design`` database producing 1.5 GW fusion power with a plasma current of 21 MA and 20 toroidal field coils generating 5.7 T Steady state profiles for T{sub ion}, T{sub e}, n{sub e}, Z{sub eff}, and P{sub rad} from the database are specified. TRANSP models the full up/down asymmetric plasma boundary within the separatrix. Effects of high-energy neutral beam injection, sawteeth mixing, toroidal field ripple, and helium ash transport are included. Results are given for the fusion rate profiles, and parameters describing effects such as alpha particle slowing down, the heating of electrons and thermal ions, and the thermalization rates. The deposition of 1 MeV neutral beam ions is predicted to peak near the plasma center, and the average beam ion energy is predicted to be half the injected energy. Sawtooth mixing is predicted to broaden the fast alpha profile. The toroidal ripple losses rate of alpha energy is estimated to be 3% before sawtooth crashes and to increase by a factor of three to four immediately following sawtooth crashes. Assumptions for the thermal He transport and the He recycling coefficient at the boundary are discussed. If the ratio of helium and energy confinement times, {tau}*{sub He}/{tau}{sub E} is less than 15, the steady state fusion power is predicted to 1.5 GW or greater. The values of the transport coefficients required for this fusion power depend on the He recycling coefficient at the separatrix. If R{sub rec} is near 1, the required He diffusivity must be much larger than that measured in tokamaks. If R{sub rec} {le} 0.50, and if the inward pinch is small, values comparable to those measured are compatible with 1.5 GW.
On the interplay between inner and outer iterations for a class of iterative methods
Giladi, E.
1994-12-31
Iterative algorithms for solving linear systems of equations often involve the solution of a subproblem at each step. This subproblem is usually another linear system of equations. For example, a preconditioned iteration involves the solution of a preconditioner at each step. In this paper, the author considers algorithms for which the subproblem is also solved iteratively. The subproblem is then said to be solved by {open_quotes}inner iterations{close_quotes} while the term {open_quotes}outer iteration{close_quotes} refers to a step of the basic algorithm. The cost of performing an outer iteration is dominated by the solution of the subproblem, and can be measured by the number of inner iterations. A good measure of the total amount of work needed to solve the original problem to some accuracy c is then, the total number of inner iterations. To lower the amount of work, one can consider solving the subproblems {open_quotes}inexactly{close_quotes} i.e. not to full accuracy. Although this diminishes the cost of solving each subproblem, it usually slows down the convergence of the outer iteration. It is therefore interesting to study the effect of solving each subproblem inexactly on the total amount of work. Specifically, the author considers strategies in which the accuracy to which the inner problem is solved, changes from one outer iteration to the other. The author seeks the `optimal strategy`, that is, the one that yields the lowest possible cost. Here, the author develops a methodology to find the optimal strategy, from the set of slowly varying strategies, for some iterative algorithms. This methodology is applied to the Chebychev iteration and it is shown that for Chebychev iteration, a strategy in which the inner-tolerance remains constant is optimal. The author also estimates this optimal constant. Then generalizations to other iterative procedures are discussed.
Caporaso, George J.; Sampayan, Stephen E.; Kirbie, Hugh C.
2007-02-06
A compact linear accelerator having at least one strip-shaped Blumlein module which guides a propagating wavefront between first and second ends and controls the output pulse at the second end. Each Blumlein module has first, second, and third planar conductor strips, with a first dielectric strip between the first and second conductor strips, and a second dielectric strip between the second and third conductor strips. Additionally, the compact linear accelerator includes a high voltage power supply connected to charge the second conductor strip to a high potential, and a switch for switching the high potential in the second conductor strip to at least one of the first and third conductor strips so as to initiate a propagating reverse polarity wavefront(s) in the corresponding dielectric strip(s).
Contaldi, Carlo R.
2014-10-01
The recent Bicep2 [1] detection of, what is claimed to be primordial B-modes, opens up the possibility of constraining not only the energy scale of inflation but also the detailed acceleration history that occurred during inflation. In turn this can be used to determine the shape of the inflaton potential V(φ) for the first time — if a single, scalar inflaton is assumed to be driving the acceleration. We carry out a Monte Carlo exploration of inflationary trajectories given the current data. Using this method we obtain a posterior distribution of possible acceleration profiles ε(N) as a function of e-fold N and derived posterior distributions of the primordial power spectrum P(k) and potential V(φ). We find that the Bicep2 result, in combination with Planck measurements of total intensity Cosmic Microwave Background (CMB) anisotropies, induces a significant feature in the scalar primordial spectrum at scales k∼ 10{sup -3} Mpc {sup -1}. This is in agreement with a previous detection of a suppression in the scalar power [2].
Modeling ITER ECH Waveguide Performance
NASA Astrophysics Data System (ADS)
Kaufman, M. C.; Lau, C. H.
2014-10-01
There are stringent requirements for mode purity and for on-target power as a percentage of source power for the ECH transmission lines on ITER. The design goal is less than 10% total power loss through the line and 95% HE11 mode at the diamond window. The dominant loss mechanism is mode conversion (MC) into higher order modes, and to maintain mode purity, these losses must be minimized. Miter bends and waveguide curvature are major sources of mode conversion. This work uses a code which calculates the mode conversion and attenuation of an arbitrary set of polarized waveguide modes in circular corrugated waveguide with non-zero axial curvature and miter bends. The transmission line is modeled as a structural beam with deformations due to misalignment of waveguide supports, tilts at the interfaces between waveguide sections, gravitational loading, and the extrusion and fabrication process. As these sources of curvature are statistical in nature, the resulting MC losses are found via Monte Carlo modeling. The results of this analysis will provide design guidance for waveguide support span lengths, requirements for minimum alignment offsets, and requirements for waveguide fabrication and quality control.
Progress on ITER Diagnostic Integration
NASA Astrophysics Data System (ADS)
Johnson, David; Feder, Russ; Klabacha, Jonathan; Loesser, Doug; Messineo, Mike; Stratton, Brentley; Wood, Rick; Zhai, Yuhu; Andrew, Phillip; Barnsley, Robin; Bertschinger, Guenter; Debock, Maarten; Reichle, Roger; Udintsev, Victor; Vayakis, George; Watts, Christopher; Walsh, Michael
2013-10-01
On ITER, front-end components must operate reliably in a hostile environment. Many will be housed in massive port plugs, which also shield the machine from radiation. Multiple diagnostics reside in a single plug, presenting new challenges for developers. Front-end components must tolerate thermally-induced stresses, disruption-induced mechanical loads, stray ECH radiation, displacement damage, and degradation due to plasma-induced coatings. The impact of failures is amplified due to the difficulty in performing robotic maintenance on these large structures. Motivated by needs to minimize disruption loads on the plugs, standardize the handling of shield modules, and decouple the parallel efforts of the many parties, the packaging strategy for diagnostics has recently focused on the use of 3 vertical shield modules inserted from the plasma side into each equatorial plug structure. At the front of each is a detachable first wall element with customized apertures. Progress on US equatorial and upper plugs will be used as examples, including the layout of components in the interspace and port cell regions. Supported by PPPL under contract DE-AC02-09CH11466 and UT-Battelle, LLC under contract DE-AC05-00OR22725 with the U.S. DOE.
Iterants, Fermions and Majorana Operators
NASA Astrophysics Data System (ADS)
Kauffman, Louis H.
Beginning with an elementary, oscillatory discrete dynamical system associated with the square root of minus one, we study both the foundations of mathematics and physics. Position and momentum do not commute in our discrete physics. Their commutator is related to the diffusion constant for a Brownian process and to the Heisenberg commutator in quantum mechanics. We take John Wheeler's idea of It from Bit as an essential clue and we rework the structure of that bit to a logical particle that is its own anti-particle, a logical Marjorana particle. This is our key example of the amphibian nature of mathematics and the external world. We show how the dynamical system for the square root of minus one is essentially the dynamics of a distinction whose self-reference leads to both the fusion algebra and the operator algebra for the Majorana Fermion. In the course of this, we develop an iterant algebra that supports all of matrix algebra and we end the essay with a discussion of the Dirac equation based on these principles.
Magnetic fusion and project ITER
Park, H.K.
1992-01-01
It has already been demonstrated that our economics and international relationship are impacted by an energy crisis. For the continuing prosperity of the human race, a new and viable energy source must be developed within the next century. It is evident that the cost will be high and will require a long term commitment to achieve this goal due to a high degree of technological and scientific knowledge. Energy from the controlled nuclear fusion is a safe, competitive, and environmentally attractive but has not yet been completely conquered. Magnetic fusion is one of the most difficult technological challenges. In modem magnetic fusion devices, temperatures that are significantly higher than the temperatures of the sun have been achieved routinely and the successful generation of tens of million watts as a result of scientific break-even is expected from the deuterium and tritium experiment within the next few years. For the practical future fusion reactor, we need to develop reactor relevant materials and technologies. The international project called International Thermonuclear Experimental Reactor (ITER)'' will fulfill this need and the success of this project will provide the most attractive long-term energy source for mankind.
Magnetic fusion and project ITER
Park, H.K.
1992-09-01
It has already been demonstrated that our economics and international relationship are impacted by an energy crisis. For the continuing prosperity of the human race, a new and viable energy source must be developed within the next century. It is evident that the cost will be high and will require a long term commitment to achieve this goal due to a high degree of technological and scientific knowledge. Energy from the controlled nuclear fusion is a safe, competitive, and environmentally attractive but has not yet been completely conquered. Magnetic fusion is one of the most difficult technological challenges. In modem magnetic fusion devices, temperatures that are significantly higher than the temperatures of the sun have been achieved routinely and the successful generation of tens of million watts as a result of scientific break-even is expected from the deuterium and tritium experiment within the next few years. For the practical future fusion reactor, we need to develop reactor relevant materials and technologies. The international project called ``International Thermonuclear Experimental Reactor (ITER)`` will fulfill this need and the success of this project will provide the most attractive long-term energy source for mankind.
Abazov, V.M.; Abbott, B.; Abolins, M.; Acharya, B.S.; Adams, M.; Adams, T.; Agelou, M.; Agram, J.-L.; Ahn, S.H.; Ahsan, M.; Alexeev, G.D.; /Buenos Aires U. /Rio de Janeiro, CBPF /Rio de Janeiro State U. /Sao Paulo, IFT /Alberta U. /Simon Fraser U. /York U., Canada /McGill U. /Beijing, Inst. High Energy Phys. /Hefei, CUST /Andes U., Bogota
2006-05-01
A search for gaugino pair production with a trilepton signature in the framework of R-parity violating supersymmetry via the couplings {lambda}{sub 121}, {lambda}{sub 122}, or {lambda}{sub 133} is presented. The data, corresponding to an integrated luminosity of L {approx} 360 pb{sup -1}, were collected from April 2002 to August 2004 with the D0 detector at the Fermilab Tevatron Collider, at a center-of-mass energy of {radical}s = 1.96 TeV. This analysis considers final states with three charged leptons with the flavor combinations ee{ell}, {mu}{mu}{ell}, and ee{tau} ({ell} = e or {mu}). No evidence for supersymmetry is found and limits at the 95% confidence level are set on the gaugino pair production cross section and lower bounds on the masses of the lightest neutralino and chargino are derived in two supersymmetric models.
Iterative and FEM methods to solve the 2-D Radiative Transfer Equation with specular reflexion
NASA Astrophysics Data System (ADS)
Le Hardy, David; Favennec, Yann; Rousseau, Benoît
2016-01-01
The present paper deals with iterative algorithms coupled with finite element methods (FEM) to solve the Radiative Transfer Equation (RTE) within semi-transparent heterogenous materials where specular reflexions occur on their boundaries. As our intention is to use such solution for inversion, the forward model should be solved as fastly as possible. This communication compares, in terms of both accuracy and CPU, the Discontinuous Galerkin (DG) method with the Streamline Upwind Petrov-Galerkin (SUPG) method, both being coupled with the Discrete Ordinate Method. Next, several iteratives methods used to accelerate the convergence are compared. These methods are the Gauss-Siedel (GS), the Source-Iteration (SI) and the Successive Over-Relaxation (SOR) methods.
Practical improvements of multi-grid iteration for adaptive mesh refinement method
NASA Astrophysics Data System (ADS)
Miyashita, Hisashi; Yamada, Yoshiyuki
2005-03-01
Adaptive mesh refinement(AMR) is a powerful tool to efficiently solve multi-scaled problems. However, the vanilla AMR method has a well-known critical demerit, i.e., it cannot be applied to non-local problems. Although multi-grid iteration (MGI) can be regarded as a good remedy for a non-local problem such as the Poisson equation, we observed fundamental difficulties in applying the MGI technique in AMR to realistic problems under complicated mesh layouts because it does not converge or it requires too many iterations even if it does converge. To cope with the problem, when updating the next approximation in the MGI process, we calculate the precise total corrections that are relatively accurate to the current residual by introducing a new iteration for such a total correction. This procedure greatly accelerates the MGI convergence speed especially under complicated mesh layouts.
Parallel computing for simultaneous iterative tomographic imaging by graphics processing units
NASA Astrophysics Data System (ADS)
Bello-Maldonado, Pedro D.; López, Ricardo; Rogers, Colleen; Jin, Yuanwei; Lu, Enyue
2016-05-01
In this paper, we address the problem of accelerating inversion algorithms for nonlinear acoustic tomographic imaging by parallel computing on graphics processing units (GPUs). Nonlinear inversion algorithms for tomographic imaging often rely on iterative algorithms for solving an inverse problem, thus computationally intensive. We study the simultaneous iterative reconstruction technique (SIRT) for the multiple-input-multiple-output (MIMO) tomography algorithm which enables parallel computations of the grid points as well as the parallel execution of multiple source excitation. Using graphics processing units (GPUs) and the Compute Unified Device Architecture (CUDA) programming model an overall improvement of 26.33x was achieved when combining both approaches compared with sequential algorithms. Furthermore we propose an adaptive iterative relaxation factor and the use of non-uniform weights to improve the overall convergence of the algorithm. Using these techniques, fast computations can be performed in parallel without the loss of image quality during the reconstruction process.
Advanced concepts for acceleration
Keefe, D.
1986-07-01
Selected examples of advanced accelerator concepts are reviewed. Such plasma accelerators as plasma beat wave accelerator, plasma wake field accelerator, and plasma grating accelerator are discussed particularly as examples of concepts for accelerating relativistic electrons or positrons. Also covered are the pulsed electron-beam, pulsed laser accelerator, inverse Cherenkov accelerator, inverse free-electron laser, switched radial-line accelerators, and two-beam accelerator. Advanced concepts for ion acceleration discussed include the electron ring accelerator, excitation of waves on intense electron beams, and two-wave combinations. (LEW)
del Amo Sanchez, P.; Lees, J.P.; Poireau, V.; Prencipe, E.; Tisserand, V.; Garra Tico, J.; Grauges, E.; Martinelli, M.; Milanes, D.A.; Palano, A.; Pappagallo, M.; Eigen, G.; Stugu, B.; Sun, L.; Brown, D.N.; Kerth, L.T.; Kolomensky, Yu.G.; Lynch, G.; Osipenkov, I.L.; Koch, H.; Schroeder, T.; /Ruhr U., Bochum /British Columbia U. /Brunel U. /Novosibirsk, IYF /UC, Irvine /UC, Riverside /UC, Santa Barbara /UC, Santa Cruz /Caltech /Cincinnati U. /Colorado U. /Colorado State U. /Dortmund U. /Dresden, Tech. U. /Ecole Polytechnique /Edinburgh U. /INFN, Ferrara /Ferrara U. /INFN, Ferrara /INFN, Ferrara /Ferrara U. /INFN, Ferrara /Frascati /INFN, Genoa /Genoa U. /INFN, Genoa /INFN, Genoa /Genoa U. /INFN, Genoa /Indian Inst. Tech., Guwahati /Harvard U. /Harvey Mudd Coll. /Heidelberg U. /Humboldt U., Berlin /Imperial Coll., London /Iowa State U. /Iowa State U. /Johns Hopkins U. /Paris U., VI-VII /LLNL, Livermore /Liverpool U. /Queen Mary, U. of London /Royal Holloway, U. of London /Royal Holloway, U. of London /Louisville U. /Mainz U., Inst. Kernphys. /Manchester U. /Maryland U. /Massachusetts U., Amherst /MIT /McGill U. /Milan U. /Milan U. /Milan U. /Milan U. /Milan U. /Mississippi U. /Montreal U. /INFN, Naples /Naples U. /NIKHEF, Amsterdam /NIKHEF, Amsterdam /Notre Dame U. /Ohio State U. /Oregon U. /INFN, Padua /Padua U. /INFN, Padua /INFN, Padua /Padua U. /Paris U., VI-VII /INFN, Perugia /Perugia U. /INFN, Pisa /Pisa U. /INFN, Pisa /Pisa, Scuola Normale Superiore /INFN, Pisa /Pisa U. /INFN, Pisa /Princeton U. /INFN, Rome /INFN, Rome /Rome U. /INFN, Rome /INFN, Rome /Rome U. /INFN, Rome /INFN, Rome /Rome U. /INFN, Rome /INFN, Rome /Rome U. /Rostock U. /Rutherford /DAPNIA, Saclay /SLAC /South Carolina U. /Southern Methodist U. /Stanford U., Phys. Dept. /SUNY, Albany /Tel Aviv U. /Tennessee U. /Texas Nuclear Corp., Austin /Texas U., Dallas /INFN, Turin /Turin U. /INFN, Trieste /Trieste U. /Valencia U. /Victoria U. /Warwick U. /Wisconsin U., Madison
2011-06-22
Searches for B mesons decaying to final states containing a baryon and a lepton are performed, where the baryon is either {Lambda}{sub c} or {Lambda} and the lepton is a muon or an electron. These decays violate both baryon and lepton number and would be a signature of physics beyond the standard model. No significant signal is observed in any of the decay modes, and upper limits in the range (3.2 - 520) x 10{sup -8} are set on the branching fractions at the 90% confidence level.
Accelerators and the Accelerator Community
Malamud, Ernest; Sessler, Andrew
2008-06-01
In this paper, standing back--looking from afar--and adopting a historical perspective, the field of accelerator science is examined. How it grew, what are the forces that made it what it is, where it is now, and what it is likely to be in the future are the subjects explored. Clearly, a great deal of personal opinion is invoked in this process.
Recombination between bacteriophage lambda and plasmid pBR322 in Escherichia coli.
Pogue-Geile, K L; Dassarma, S; King, S R; Jaskunas, S R
1980-01-01
Recombinant lambda phages were isolated that resulted from recombination between the lambda genome and plasmid pBR322 in Escherichia coli, even though these deoxyribonucleic acids (DNAs) did not share extensive regions of homology. The characterization of these recombinant DNAs by heteroduplex analysis and restriction endonucleases is described. All but one of the recombinants appeared to have resulted from reciprocal recombination between a site on lambda DNA and a site on the plasmid. In general, there were two classes of recombinants. One class appeared to have resulted from recombination at the phage attachment site that probably resulted from lambda integration into secondary attachment sites on the plasmid. Seven different secondary attachment sites on pBR322 were found. The other class resulted from plasmid integration at other sites that were widely scattered on the lambda genome. For this second class of recombinants, more than one site on the plasmid could recombine with lambda DNA. Thus, the recombination did not appear to be site specific with respect to lambda or the plasmid. Possible mechanisms for generating these recombinants are discussed. Images PMID:6247334
Regularized iterative weighted filtered backprojection for helical cone-beam CT
Sunnegaardh, Johan; Danielsson, Per-Erik
2008-09-15
Contemporary reconstruction methods employed for clinical helical cone-beam computed tomography (CT) are analytical (noniterative) but mathematically nonexact, i.e., the reconstructed image contains so called cone-beam artifacts, especially for higher cone angles. Besides cone artifacts, these methods also suffer from windmill artifacts: alternating dark and bright regions creating spiral-like patterns occurring in the vicinity of high z-direction derivatives. In this article, the authors examine the possibility to suppress cone and windmill artifacts by means of iterative application of nonexact three-dimensional filtered backprojection, where the analytical part of the reconstruction brings about accelerated convergence. Specifically, they base their investigations on the weighted filtered backprojection method [Stierstorfer et al., Phys. Med. Biol. 49, 2209-2218 (2004)]. Enhancement of high frequencies and amplification of noise is a common but unwanted side effect in many acceleration attempts. They have employed linear regularization to avoid these effects and to improve the convergence properties of the iterative scheme. Artifacts and noise, as well as spatial resolution in terms of modulation transfer functions and slice sensitivity profiles have been measured. The results show that for cone angles up to {+-}2.78 deg., cone artifacts are suppressed and windmill artifacts are alleviated within three iterations. Furthermore, regularization parameters controlling spatial resolution can be tuned so that image quality in terms of spatial resolution and noise is preserved. Simulations with higher number of iterations and long objects (exceeding the measured region) verify that the size of the reconstructible region is not reduced, and that the regularization greatly improves the convergence properties of the iterative scheme. Taking these results into account, and the possibilities to extend the proposed method with more accurate modeling of the acquisition
Search for B{sup 0}{yields}{lambda}{sub c}{sup +}{lambda}{sub c}{sup -} decay at Belle
Uchida, Y.; Iwabuchi, M.; Kim, Y. J.; Ozaki, H.; Kichimi, H.; Adachi, I.; Haba, J.; Hazumi, M.; Itoh, R.; Iwasaki, Y.; Katayama, N.; Krokovny, P.; Nakao, M.; Nishida, S.; Nozaki, T.; Sakai, Y.; Suzuki, S. Y.; Takasaki, F.; Tanaka, M.; Uno, S.
2008-03-01
We search for the doubly charmed baryonic decay B{sup 0}{yields}{lambda}{sub c}{sup +}{lambda}{sub c}{sup -}, in a data sample of 520x10{sup 6} BB events accumulated at the {upsilon}(4S) resonance with the Belle detector at the KEKB asymmetric-energy e{sup +}e{sup -} collider. We find no significant signal and set an upper limit of B(B{sup 0}{yields}{lambda}{sub c}{sup +}{lambda}{sub c}{sup -})<6.2x10{sup -5} at 90% confidence level. The result is significantly below a naive extrapolation from B(B{sup -}{yields}{xi}{sub c}{sup 0}{lambda}{sub c}{sup -}) assuming a simple Cabibbo-suppression factor of |V{sub cd}/V{sub cs}|{sup 2}. The small branching fraction may be attributed to a suppression due to the large momentum of the baryonic decay products, which has been observed in other charmed baryonic two-body B decays.
Formation and Acceleration Physics on Plasma Injector 1
NASA Astrophysics Data System (ADS)
Howard, Stephen
2012-10-01
Plasma Injector 1 (PI-1) is a two stage coaxial Marshal gun with conical accelerator electrodes, similar in shape to the MARAUDER device, with power input of the same topology as the RACE device. The goal of PI-1 research is to produce a self-confined compact toroid with high-flux (200 mWb), high-density (3x10^16 cm-3) and moderate initial temperature (100 eV) to be used as the target plasma in a MTF reactor. PI-1 is 5 meters long and 1.9 m in diameter at the expansion region where a high aspect ratio (4.4) spheromak is formed with a minimum lambda of 9 m-1. The acceleration stage is 4 m long and tapers to an outer diameter of 40 cm. The capacitor banks store 0.5 MJ for formation and 1.13 MJ for acceleration. Power is delivered via 62 independently controlled switch modules. Several geometries for formation bias field, inner electrodes and target chamber have been tested, and trends in accelerator efficiency and target lifetime have been observed. Thomson scattering and ion Doppler spectroscopy show significant heating (>100 eV) as the CT is compressed in the conical accelerator. B-dot probes show magnetic field structure consistent with Grad-Shafranov models and MHD simulations, and CT axial length depends strongly on the lambda profile.
Recombinant lambda-phage nanobioparticles for tumor therapy in mice models.
Ghaemi, Amir; Soleimanjahi, Hoorieh; Gill, Pooria; Hassan, Zuhair; Jahromi, Soodeh Razeghi M; Roohvand, Farzin
2010-01-01
Lambda phages have considerable potential as gene delivery vehicles due to their genetic tractability, low cost, safety and physical characteristics in comparison to other nanocarriers and gene porters. Little is known concerning lambda phage-mediated gene transfer and expression in mammalian hosts. We therefore performed experiments to evaluate lambda-ZAP bacteriophage-mediated gene transfer and expression in vitro. For this purpose, we constructed recombinant lambda-phage nanobioparticles containing a mammalian expression cassette encoding enhanced green fluorescent protein (EGFP) and E7 gene of human papillomavirus type 16 (lambda-HPV-16 E7) using Lambda ZAP- CMV XR vector. Four cell lines (COS-7, CHO, TC-1 and HEK-239) were transduced with the nanobioparticles. We also characterized the therapeutic anti-tumor effects of the recombinant lambda-HPV-16 E7 phage in C57BL/6 tumor mice model as a cancer vaccine. Obtained results showed that delivery and expression of these genes in fibroblastic cells (COS-7 and CHO) are more efficient than epithelial cells (TC-1 and HEK-239) using these nanobioparticles. Despite the same phage M.O.I entry, the internalizing titers of COS-7 and CHO cells were more than TC-1 and HEK-293 cells, respectively. Mice vaccinated with lambda-HPV-16 E7 are able to generate potent therapeutic antitumor effects against challenge with E7- expressing tumor cell line, TC-1 compared to group treated with the wild phage. The results demonstrated that the recombinant lambda-phages, due to their capabilities in transducing mammalian cells, can also be considered in design and construction of novel and safe phage-based nanomedicines. PMID:20459865
Development of a Tritium Extruder for ITER Pellet Injection
M.J. Gouge; P.W. Fisher
1998-09-01
As part of the International Thermonuclear Experimental Reactor (ITER) plasma fueling development program, Oak Ridge National Laboratory (ORNL) has fabricated a pellet injection system to test the mechanical and thermal properties of extruded tritium. Hydrogenic pellets will be used in ITER to sustain the fusion power in the plasma core and may be crucial in reducing first-wall tritium inventories by a process of "isotopic fueling" in which tritium-rich pellets fuel the burning plasma core and deuterium gas fuels the edge. This repeating single-stage pneumatic pellet injector, called the Tritium-Proof-of-Principle Phase II (TPOP-II) Pellet Injector, has a piston-driven mechanical extruder and is designed to extrude and accelerate hydrogenic pellets sized for the ITER device. The TPOP-II program has the following development goals: evaluate the feasibility of extruding tritium and deuterium-tritium (D-T) mixtures for use in future pellet injection systems; determine the mechanical and thermal properties of tritium and D-T extrusions; integrate, test, and evaluate the extruder in a repeating, single-stage light gas gun that is sized for the ITER application (pellet diameter -7 to 8 mm); evaluate options for recycling propellant and extruder exhaust gas; and evaluate operability and reliability of ITER prototypical fueling systems in an environment of significant tritium inventory that requires secondary and room containment systems. In tests with deuterium feed at ORNL, up to 13 pellets per extrusion have been extruded at rates up to 1 Hz and accelerated to speeds of 1.0 to 1.1 km/s, using hydrogen propellant gas at a supply pressure of 65 bar. Initially, deuterium pellets 7.5 mm in diameter and 11 mm in length were produced-the largest cryogenic pellets produced by the fusion program to date. These pellets represent about a 10% density perturbation to ITER. Subsequently, the extruder nozzle was modified to produce pellets that are almost 7.5-mm right circular
Antiviral Effect of Interferon Lambda Against Lymphocytic Choriomeningitis Virus.
Lukacikova, Lubomira; Oveckova, Ingrid; Betakova, Tatiana; Laposova, Katarina; Polcicova, Katarina; Pastorekova, Silvia; Pastorek, Jaromir; Tomaskova, Jana
2015-07-01
Lambda interferons inhibit replication of many viruses, but their role in the inhibition of lymphocytic choriomeningitis virus (LCMV) infection remains unclear. In this study, we examined the antiviral effects of interferon (IFN)-λ2 and IFN-λ3 against LCMV in A549 cells. We found that IFN-λ2 is a more potent inhibitor of LCMV strain MX compared with IFN-λ3, whereas both cytokines have similar antiviral effects against an immunosuppressive variant of LCMV, clone-13. We also demonstrated that the antiviral activity of IFN-λ2 is more effective if it is delivered early rather than after establishment of a long-term infection, suggesting that virus replication is only partially responsive to the cytokine. In agreement with this observation, we showed that LCMV infection significantly reduces IFNLR1 mRNA expression in infected cells. In addition, LCMV infection, to some extent, compromises the signal transduction pathway of IFN-λ2. This implies that IFN receptors as well as their downstream signaling components could be selectively targeted either directly by LCMV proteins or indirectly by cellular factor(s) that are induced or activated by LCMV infection.
Scaling and resonances in elementary K{sup +{Lambda}} photoproduction
Schumacher, R. A.; Sargsian, M. M.
2011-02-15
Recent cross-section data for the reaction {gamma}+p{yields}K{sup +}+{Lambda} are examined for evidence of scaling in both the low-t Regge domain and in the high-{radical}(s) and -t domain where constituent counting may apply. It is shown that the reaction does scale in both regimes. At large center-of-mass angles, s{sup -7} scaling appears to hold at essentially all -t but with angle-dependent oscillations. The scaled data show particularly strong evidence for s-channel resonances for -t below 2 GeV{sup 2} and for W below about 2.3 GeV. The dominant contributions are consistent with an N{sup *}S{sub 11} resonance at 1690 MeV, a P{sub 13} resonance at 1920 MeV, and a D{sub 13} resonance at 2100 MeV, which interfere to give the observed strong angular dependence.
Lambda and the edge of chaos in recurrent neural networks.
Seifter, Jared; Reggia, James A
2015-01-01
The idea that there is an edge of chaos, a region in the space of dynamical systems having special meaning for complex living entities, has a long history in artificial life. The significance of this region was first emphasized in cellular automata models when a single simple measure, λCA, identified it as a transitional region between order and chaos. Here we introduce a parameter λNN that is inspired by λCA but is defined for recurrent neural networks. We show through a series of systematic computational experiments that λNN generally orders the dynamical behaviors of randomly connected/weighted recurrent neural networks in the same way that λCA does for cellular automata. By extending this ordering to larger values of λNN than has typically been done with λCA and cellular automata, we find that a second edge-of-chaos region exists on the opposite side of the chaotic region. These basic results are found to hold under different assumptions about network connectivity, but vary substantially in their details. The results show that the basic concept underlying the lambda parameter can usefully be extended to other types of complex dynamical systems than just cellular automata.
Comparison of Cluster Lensing Profiles with Lambda CDM Predictions
Broadhurst, Tom; Umetsu, Keiichi; Medezinski, Elinor; Oguri, Masamune; Rephaeli, Yoel; /Tel Aviv U. /San Diego, CASS
2008-05-21
We derive lens distortion and magnification profiles of four well known clusters observed with Subaru. Each cluster is very well fitted by the general form predicted for Cold Dark Matter (CDM) dominated halos, with good consistency found between the independent distortion and magnification measurements. The inferred level of mass concentration is surprisingly high, 8 < c{sub vir} < 15 (
The Physics Basis of ITER Confinement
Wagner, F.
2009-02-19
ITER will be the first fusion reactor and the 50 year old dream of fusion scientists will become reality. The quality of magnetic confinement will decide about the success of ITER, directly in the form of the confinement time and indirectly because it decides about the plasma parameters and the fluxes, which cross the separatrix and have to be handled externally by technical means. This lecture portrays some of the basic principles which govern plasma confinement, uses dimensionless scaling to set the limits for the predictions for ITER, an approach which also shows the limitations of the predictions, and describes briefly the major characteristics and physics behind the H-mode--the preferred confinement regime of ITER.
Designing Diagnostics to Survive in ITER
NASA Astrophysics Data System (ADS)
Watts, Christopher; ITER Team
2014-10-01
Adapting diagnostics to withstand the incredibly harsh environment of the ITER D-T plasma is a formidable engineering task. Hindrances include not only the nuclear environment, but also the high radiative heat fluxes, high particle fluxes and stray ECH radiation. Strategies to mitigate the impact of these run the gamut from shielding, through recessing, through appropriate materials selection, to refurbishment. Examples include the Langmuir probe system, where individual probes are protected by passive heat shields; retroreflectors recessed into the tokamak first wall in deep, baffled tunnels; plasma mirror cleaning systems; electronics components like piezo crystals and x-ray detectors vetted for the nuclear environment. These and other ITER diagnostic system designs will be highlighted to emphasize their strategies for dealing with the ITER environment. *The views and opinions expressed herein do not necessarily reflect those of the ITER Organization.
Archimedes' Pi--An Introduction to Iteration.
ERIC Educational Resources Information Center
Lotspeich, Richard
1988-01-01
One method (attributed to Archimedes) of approximating pi offers a simple yet interesting introduction to one of the basic ideas of numerical analysis, an iteration sequence. The method is described and elaborated. (PK)
NASA Technical Reports Server (NTRS)
Fairbanks, W. M.; Lipa, J. A.
1984-01-01
A measurement of the heat capacity singularity of helium at the lambda transition was performed with the aim of improving tests of the Renormalization Group (RG) predictions for the static thermodynamic behavior near the singularity. The goal was to approach as closely as possible to the lambda-point while making heat capacity measurements of high accuracy. To do this, a new temperature sensor capable of unprecedented resolution near the lambda-point, and two thermal control systems were used. A short description of the theoretical background and motivation is given. The initial apparatus and results are also described.
Cloning and sequencing of human lambda immunoglobulin genes by the polymerase chain reaction.
Songsivilai, S; Bye, J M; Marks, J D; Hughes-Jones, N C
1990-12-01
Universal oligonucleotide primers, designed for amplifying and sequencing genes encoding the rearranged human lambda immunoglobulin variable region, were validated by amplification of the lambda light chain genes from four human heterohybridoma cell lines and in the generation of a cDNA library of human V lambda sequences from Epstein-Barr virus-transformed human peripheral blood lymphocytes. This technique allows rapid cloning and sequencing of human immunoglobulin genes, and has potential applications in the rescue of unstable human antibody-producing cell lines and in the production of human monoclonal antibodies.
High Resolution Spectroscopy of {sub {lambda}}{sup 12}B by Electroproduction
Iodice, M.; Cusanno, F.; Urciuoli, G. M.; Acha, A.; Ambrozewicz, P.; Coman, L.; Markowitz, P.; Moteabbed, M.; Raue, B.; Reinhold, J.; Aniol, K. A.; Margaziotis, D. J.; Baturin, P.; Jiang, X.; McCormick, K.; Bertin, P. Y.; Camsonne, A.; Ferdi, C.; Blomqvist, K. I.
2007-08-03
An experiment measuring electroproduction of hypernuclei has been performed in hall A at Jefferson Lab on a {sup 12}C target. In order to increase counting rates and provide unambiguous kaon identification two superconducting septum magnets and a ring imaging Cherenkov detector were added to the hall A standard equipment. An unprecedented energy resolution of less than 700 keV FWHM has been achieved. Thus, the observed {sub {lambda}}{sup 12}B spectrum shows for the first time identifiable strength in the core-excited region between the ground-state s-wave {lambda} peak and the 11 MeV p-wave {lambda} peak.
Design of a -1 MV dc UHV power supply for ITER NBI
NASA Astrophysics Data System (ADS)
Watanabe, K.; Yamamoto, M.; Takemoto, J.; Yamashita, Y.; Dairaku, M.; Kashiwagi, M.; Taniguchi, M.; Tobari, H.; Umeda, N.; Sakamoto, K.; Inoue, T.
2009-05-01
Procurement of a dc -1 MV power supply system for the ITER neutral beam injector (NBI) is shared by Japan and the EU. The Japan Atomic Energy Agency as the Japan Domestic Agency (JADA) for ITER contributes to the procurement of dc -1 MV ultra-high voltage (UHV) components such as a dc -1 MV generator, a transmission line and a -1 MV insulating transformer for the ITER NBI power supply. The inverter frequency of 150 Hz in the -1 MV power supply and major circuit parameters have been proposed and adopted in the ITER NBI. The dc UHV insulation has been carefully designed since dc long pulse insulation is quite different from conventional ac insulation or dc short pulse systems. A multi-layer insulation structure of the transformer for a long pulse up to 3600 s has been designed with electric field simulation. Based on the simulation the overall dimensions of the dc UHV components have been finalized. A surge energy suppression system is also essential to protect the accelerator from electric breakdowns. The JADA contributes to provide an effective surge suppression system composed of core snubbers and resistors. Input energy into the accelerator from the power supply can be reduced to about 20 J, which satisfies the design criteria of 50 J in total in the case of breakdown at -1 MV.
Novel aspects of plasma control in ITER
NASA Astrophysics Data System (ADS)
Humphreys, D.; Ambrosino, G.; de Vries, P.; Felici, F.; Kim, S. H.; Jackson, G.; Kallenbach, A.; Kolemen, E.; Lister, J.; Moreau, D.; Pironti, A.; Raupp, G.; Sauter, O.; Schuster, E.; Snipes, J.; Treutterer, W.; Walker, M.; Welander, A.; Winter, A.; Zabeo, L.
2015-02-01
ITER plasma control design solutions and performance requirements are strongly driven by its nuclear mission, aggressive commissioning constraints, and limited number of operational discharges. In addition, high plasma energy content, heat fluxes, neutron fluxes, and very long pulse operation place novel demands on control performance in many areas ranging from plasma boundary and divertor regulation to plasma kinetics and stability control. Both commissioning and experimental operations schedules provide limited time for tuning of control algorithms relative to operating devices. Although many aspects of the control solutions required by ITER have been well-demonstrated in present devices and even designed satisfactorily for ITER application, many elements unique to ITER including various crucial integration issues are presently under development. We describe selected novel aspects of plasma control in ITER, identifying unique parts of the control problem and highlighting some key areas of research remaining. Novel control areas described include control physics understanding (e.g., current profile regulation, tearing mode (TM) suppression), control mathematics (e.g., algorithmic and simulation approaches to high confidence robust performance), and integration solutions (e.g., methods for management of highly subscribed control resources). We identify unique aspects of the ITER TM suppression scheme, which will pulse gyrotrons to drive current within a magnetic island, and turn the drive off following suppression in order to minimize use of auxiliary power and maximize fusion gain. The potential role of active current profile control and approaches to design in ITER are discussed. Issues and approaches to fault handling algorithms are described, along with novel aspects of actuator sharing in ITER.
Iterative consolidation of unorganized point clouds.
Liu, Shengjun; Chan, Kwan-Chung; Wang, Charlie C L
2012-01-01
Unorganized point clouds obtained from 3D shape acquisition devices usually present noise, outliers, and nonuniformities. The proposed framework consolidates unorganized points through an iterative procedure of interlaced downsampling and upsampling. Selection operations remove outliers while preserving geometric details. The framework improves the uniformity of points by moving the downsampled particles and refining point samples. Surface extrapolation fills missed regions. Moreover, an adaptive sampling strategy speeds up the iterations. Experimental results demonstrate the framework's effectiveness.
Programmable Iterative Optical Image And Data Processing
NASA Technical Reports Server (NTRS)
Jackson, Deborah J.
1995-01-01
Proposed method of iterative optical image and data processing overcomes limitations imposed by loss of optical power after repeated passes through many optical elements - especially, beam splitters. Involves selective, timed combination of optical wavefront phase conjugation and amplification to regenerate images in real time to compensate for losses in optical iteration loops; timing such that amplification turned on to regenerate desired image, then turned off so as not to regenerate other, undesired images or spurious light propagating through loops from unwanted reflections.
Iterative methods based upon residual averaging
NASA Technical Reports Server (NTRS)
Neuberger, J. W.
1980-01-01
Iterative methods for solving boundary value problems for systems of nonlinear partial differential equations are discussed. The methods involve subtracting an average of residuals from one approximation in order to arrive at a subsequent approximation. Two abstract methods in Hilbert space are given and application of these methods to quasilinear systems to give numerical schemes for such problems is demonstrated. Potential theoretic matters related to the iteration schemes are discussed.
Threshold power and energy confinement for ITER
Takizuka, T.
1996-12-31
In order to predict the threshold power for L-H transition and the energy confinement performance in ITER, assembling of database and analyses of them have been progressed. The ITER Threshold Database includes data from 10 divertor tokamaks. Investigation of the database gives a scaling of the threshold power of the form P{sub thr} {proportional_to} B{sub t} n{sub e}{sup 0.75} R{sup 2} {times} (n{sub e} R{sup 2}){sup +-0.25}, which predicts P{sub thr} = 100 {times} 2{sup 0{+-}1} MW for ITER at n{sub e} = 5 {times} 10{sup 19} m{sup {minus}3}. The ITER L-mode Confinement Database has also been expanded by data from 14 tokamaks. A scaling of the thermal energy confinement time in L-mode and ohmic phases is obtained; {tau}{sub th} {approximately} I{sub p} R{sup 1.8} n{sub e}{sup 0.4{sub P{sup {minus}0.73}}}. At the ITER parameter, it becomes about 2.2 sec. For the ignition in ITER, more than 2.5 times of improvement will be required from the L-mode. The ITER H-mode Confinement Database is expanded from data of 6 tokamaks to data of 11 tokamaks. A {tau}{sub th} scaling for ELMy H-mode obtained by a standard regression analysis predicts the ITER confinement time of {tau}{sub th} = 6 {times} (1 {+-} 0.3) sec. The degradation of {tau}{sub th} with increasing n{sub e} R{sup 2} (or decreasing {rho}{sub *}) is not found for ELMy H-mode. An offset linear law scaling with a dimensionally correct form also predicts nearly the same {tau}{sub th} value.
Novel aspects of plasma control in ITER
Humphreys, D.; Jackson, G.; Walker, M.; Welander, A.; Ambrosino, G.; Pironti, A.; Felici, F.; Kallenbach, A.; Raupp, G.; Treutterer, W.; Kolemen, E.; Lister, J.; Sauter, O.; Moreau, D.; Schuster, E.
2015-02-15
ITER plasma control design solutions and performance requirements are strongly driven by its nuclear mission, aggressive commissioning constraints, and limited number of operational discharges. In addition, high plasma energy content, heat fluxes, neutron fluxes, and very long pulse operation place novel demands on control performance in many areas ranging from plasma boundary and divertor regulation to plasma kinetics and stability control. Both commissioning and experimental operations schedules provide limited time for tuning of control algorithms relative to operating devices. Although many aspects of the control solutions required by ITER have been well-demonstrated in present devices and even designed satisfactorily for ITER application, many elements unique to ITER including various crucial integration issues are presently under development. We describe selected novel aspects of plasma control in ITER, identifying unique parts of the control problem and highlighting some key areas of research remaining. Novel control areas described include control physics understanding (e.g., current profile regulation, tearing mode (TM) suppression), control mathematics (e.g., algorithmic and simulation approaches to high confidence robust performance), and integration solutions (e.g., methods for management of highly subscribed control resources). We identify unique aspects of the ITER TM suppression scheme, which will pulse gyrotrons to drive current within a magnetic island, and turn the drive off following suppression in order to minimize use of auxiliary power and maximize fusion gain. The potential role of active current profile control and approaches to design in ITER are discussed. Issues and approaches to fault handling algorithms are described, along with novel aspects of actuator sharing in ITER.
Koenig, B.; Koerner, J.G.; Kraemer, M.
1994-03-01
We consider possibilities to determine the handedness of {ital b}{r_arrow}{ital c} current transitions using semileptonic baryonic {Lambda}{sub {ital b}}{r_arrow}{Lambda}{sub {ital c}} transitions. We propose to analyze the longitudinal polarization of the daughter baryon {Lambda}{sub {ital c}} by using momentum-spin correlation measurements in the form of forward-backward (FB) asymmetry measures involving its nonleptonic decay products. We use an explicit form factor model to determine the longitudinal polarization of {Lambda}{sub {ital c}} in the semileptonic decay {Lambda}{sub {ital b}}{r_arrow}{Lambda}{sub {ital c}}+{ital l}{sup {minus}}+{bar {nu}}{sub {ital l}}. The mean longitudinal polarization of {Lambda}{sub {ital c}} is negative (positive) for left-chiral (right-chiral) {ital b}{r_arrow}{ital c} current transitions. The frame-dependent longitudinal polarization of {Lambda}{sub {ital c}} is large ({congruent}80%) in the {Lambda}{sub {ital b}} rest frame and somewhat smaller (30%--40%) in the lab frame when the {Lambda}{sub {ital b}}`s are produced on the {ital Z}{sup 0} peak. We suggest to use nonleptonic decay modes of {Lambda}{sub {ital c}} to analyze its polarization and thereby to determine the chirality of the {ital b}{r_arrow}{ital c} transition. Since {Lambda}{sub {ital b}}`s produced on the {ital Z}{sup 0} are expected to be polarized we discuss issues of the polarization transfer in {Lambda}{sub {ital b}}{r_arrow}{Lambda}{sub {ital c}} transitions. We also investigate the {ital p}{sub {perpendicular}}- and {ital p}-cut sensitivity of our predictions for the polarization of {Lambda}{sub {ital c}}.
Improved hybrid iterative optimization method for seismic full waveform inversion
NASA Astrophysics Data System (ADS)
Wang, Yi; Dong, Liang-Guo; Liu, Yu-Zhu
2013-06-01
In full waveform inversion (FWI), Hessian information of the misfit function is of vital importance for accelerating the convergence of the inversion; however, it usually is not feasible to directly calculate the Hessian matrix and its inverse. Although the limited memory Broyden-Fletcher-Goldfarb-Shanno (L-BFGS) or Hessian-free inexact Newton (HFN) methods are able to use approximate Hessian information, the information they collect is limited. The two methods can be interlaced because they are able to provide Hessian information for each other; however, the performance of the hybrid iterative method is dependent on the effective switch between the two methods. We have designed a new scheme to realize the dynamic switch between the two methods based on the decrease ratio (DR) of the misfit function (objective function), and we propose a modified hybrid iterative optimization method. In the new scheme, we compare the DR of the two methods for a given computational cost, and choose the method with a faster DR. Using these steps, the modified method always implements the most efficient method. The results of Marmousi and over thrust model testings indicate that the convergence with our modified method is significantly faster than that in the L-BFGS method with no loss of inversion quality. Moreover, our modified outperforms the enriched method by a little speedup of the convergence. It also exhibits better efficiency than the HFN method.
Iterative feature refinement for accurate undersampled MR image reconstruction
NASA Astrophysics Data System (ADS)
Wang, Shanshan; Liu, Jianbo; Liu, Qiegen; Ying, Leslie; Liu, Xin; Zheng, Hairong; Liang, Dong
2016-05-01
Accelerating MR scan is of great significance for clinical, research and advanced applications, and one main effort to achieve this is the utilization of compressed sensing (CS) theory. Nevertheless, the existing CSMRI approaches still have limitations such as fine structure loss or high computational complexity. This paper proposes a novel iterative feature refinement (IFR) module for accurate MR image reconstruction from undersampled K-space data. Integrating IFR with CSMRI which is equipped with fixed transforms, we develop an IFR-CS method to restore meaningful structures and details that are originally discarded without introducing too much additional complexity. Specifically, the proposed IFR-CS is realized with three iterative steps, namely sparsity-promoting denoising, feature refinement and Tikhonov regularization. Experimental results on both simulated and in vivo MR datasets have shown that the proposed module has a strong capability to capture image details, and that IFR-CS is comparable and even superior to other state-of-the-art reconstruction approaches.
A multiple right hand side iterative solver for history matching
Killough, J.E.; Sharma, Y.; Dupuy, A.; Bissell, R.; Wallis, J.
1995-12-31
History matching of oil and gas reservoirs can be accelerated by directly calculating the gradients of observed quantities (e.g., well pressure) with respect to the adjustable reserve parameters (e.g., permeability). This leads to a set of linear equations which add a significant overhead to the full simulation run without gradients. Direct Gauss elimination solvers can be used to address this problem by performing the factorization of the matrix only once and then reusing the factor matrix for the solution of the multiple right hand sides. This is a limited technique, however. Experience has shown that problems with greater than few thousand cells may not be practical for direct solvers because of computation time and memory limitations. This paper discusses the implementation of a multiple right hand side iterative linear equation solver (MRHS) for a system of adjoint equations to significantly enhance the performance of a gradient simulator.
EDITORIAL: ECRH physics and technology in ITER
NASA Astrophysics Data System (ADS)
Luce, T. C.
2008-05-01
It is a great pleasure to introduce you to this special issue containing papers from the 4th IAEA Technical Meeting on ECRH Physics and Technology in ITER, which was held 6-8 June 2007 at the IAEA Headquarters in Vienna, Austria. The meeting was attended by more than 40 ECRH experts representing 13 countries and the IAEA. Presentations given at the meeting were placed into five separate categories EC wave physics: current understanding and extrapolation to ITER Application of EC waves to confinement and stability studies, including active control techniques for ITER Transmission systems/launchers: state of the art and ITER relevant techniques Gyrotron development towards ITER needs System integration and optimisation for ITER. It is notable that the participants took seriously the focal point of ITER, rather than simply contributing presentations on general EC physics and technology. The application of EC waves to ITER presents new challenges not faced in the current generation of experiments from both the physics and technology viewpoints. High electron temperatures and the nuclear environment have a significant impact on the application of EC waves. The needs of ITER have also strongly motivated source and launcher development. Finally, the demonstrated ability for precision control of instabilities or non-inductive current drive in addition to bulk heating to fusion burn has secured a key role for EC wave systems in ITER. All of the participants were encouraged to submit their contributions to this special issue, subject to the normal publication and technical merit standards of Nuclear Fusion. Almost half of the participants chose to do so; many of the others had been published in other publications and therefore could not be included in this special issue. The papers included here are a representative sample of the meeting. The International Advisory Committee also asked the three summary speakers from the meeting to supply brief written summaries (O. Sauter
NASA Astrophysics Data System (ADS)
Quan, Haiyang; Wu, Fan; Hou, Xi
2015-10-01
New method for reconstructing rotationally asymmetric surface deviation with pixel-level spatial resolution is proposed. It is based on basic iterative scheme and accelerates the Gauss-Seidel method by introducing an acceleration parameter. This modified Successive Over-relaxation (SOR) is effective for solving the rotationally asymmetric components with pixel-level spatial resolution, without the usage of a fitting procedure. Compared to the Jacobi and Gauss-Seidel method, the modified SOR method with an optimal relaxation factor converges much faster and saves more computational costs and memory space without reducing accuracy. It has been proved by real experimental results.
Transverse stability of the primary beam in the plasma wake-field accelerator
Krall, J.; Joyce, G.
1995-06-01
The stability of the primary electron beam in the plasma wakefield accelerator is studied using a three-dimensional particle code, for cases in which a shaped electron beam, with length {ital L}{approx_gt}{lambda}{sub {ital p}} is used, where {lambda}{sub {ital p}} is the plasma wavelength. The electron-hose and the transverse two-stream instabilities are observed to cause transverse deflections of the beam, with the transverse two-stream instability having a lower growth rate. Operation in the electron-hose regime can be avoided by reducing the beam density. {copyright} 1995 {ital American Institute of Physics}.
Aberrant immunity behaviour of hybrid lambda imm21 phages containing the DNA of ColE1-type plasmids.
Windass, J D; Brammar, W J
1979-01-01
Hybrid lambda and lambda imm21 bacteriophages carrying various ColE1-type plasmids have been constructed in vitro. The lambda imm21/plasmid recombinants display aberrant immunity behaviour, giving clear plaques under conditions where the parental phages give turbid ones and being able to grow on homoimmune lysogens. lambda imm lambda/plasmid recombinants show no such unusual behaviour. Studies with hybrids of a lambda imm21 cITS phage carrying pMB9 DNA showed the operation of the plasmid's replication system to be the basic cause of the aberrant immunity behaviour. The plasmid replication system could act as a complete alternative to the phage system during vegetative phage growth. The probable reason that lambda imm21 phages show such altered phenotypes when carrying a functional plasmid replication origin, whereas lambda imm lambda and lambda imm434 (Mukai et al., 1978) phages do not, is the relative ease of titration of the phage 21 repressor to allow transcription from pR21. Various uses are considered for the altered phenotypic behaviour of lambda imm21/ColE1-type plasmid hybrids.
Continuous resonant four-wave mixing in double- Lambda level configurations of Na2
NASA Astrophysics Data System (ADS)
Babin, S.; Hinze, U.; Tiemann, E.; Wellegehausen, B.
1996-08-01
Efficient continuous resonant frequency mixing omega 4= omega 1- omega 2 + omega 3 in Na2 has been realized. A bichromatic field ( lambda 1 =488 nm, lambda 2=525 nm), generated by an Ar+ -laser-pumped Na 2 Raman laser, and radiation at lambda 3=655 nm from a dye laser interact resonantly with corresponding transitions X1 Sigma +g(v=3,J= 43) \\rightarrow B 1 Pi u(6,43) \\rightarrow X 1 Sigma +g(13, 43) \\rightarrow A 1 Sigma +g(24, 44) in a test Na2 heat pipe. For input powers of 200, 25, and 400 mW an output beam of as much as 0.2 mW at lambda 4=599 nm has been observed. Measured parameter dependences indicate an influence of interference effects. This is directly related to the discussion of lasing without inversion.
Evidence for B Semileptonic Decays into the Lambda_c Charm Baryon
Aubert, Bernard; Bona, M.; Karyotakis, Y.; Lees, J.P.; Poireau, V.; Prencipe, E.; Prudent, X.; Tisserand, V.; Garra Tico, J.; Grauges, E.; Lopez, L.; Palano, Antimo; Pappagallo, M.; Eigen, G.; Stugu, Bjarne; Sun, L.; Abrams, G.S.; Battaglia, M.; Brown, D.N.; Cahn, Robert N.; Jacobsen, R.G.; /LBL, Berkeley /Birmingham U. /Ruhr U., Bochum /Bristol U. /British Columbia U. /Brunel U. /Novosibirsk, IYF /UC, Irvine /UCLA /UC, Riverside /UC, San Diego /UC, Santa Barbara /UC, Santa Cruz /Caltech /Cincinnati U. /Colorado U. /Colorado State U. /Dortmund U. /Dresden, Tech. U. /Ecole Polytechnique /Edinburgh U. /Ferrara U. /INFN, Ferrara /Frascati /Genoa U. /INFN, Genoa /Harvard U. /Heidelberg U. /Humboldt U., Berlin /Imperial Coll., London /Iowa U. /Iowa State U. /Johns Hopkins U. /Orsay, LAL /LLNL, Livermore /Liverpool U. /Queen Mary, U. of London /Royal Holloway, U. of London /Louisville U. /Mainz U., Inst. Kernphys. /Manchester U. /Maryland U. /Massachusetts U., Amherst /MIT /McGill U. /Consorzio Milano Ricerche /INFN, Milan /Mississippi U. /Montreal U. /Mt. Holyoke Coll. /Napoli Seconda U. /INFN, Naples /NIKHEF, Amsterdam /Notre Dame U. /Ohio State U. /Oregon U. /Padua U. /INFN, Padua /Paris U., VI-VII /Pennsylvania U. /Perugia U. /INFN, Perugia /INFN, Pisa /Princeton U. /Banca di Roma /Frascati /Rostock U. /Rutherford /DAPNIA, Saclay /South Carolina U. /SLAC /Stanford U., Phys. Dept. /SUNY, Albany /Tennessee U. /Texas U. /Texas U., Dallas /Turin U. /INFN, Turin /Trieste U. /INFN, Trieste /Valencia U., IFIC /Victoria U. /Warwick U. /Wisconsin U., Madison
2008-11-05
We present the first evidence for B semileptonic decays into the charmed baryon {Lambda}{sub c}{sup +} based on 420 fb{sup -1} of data collected at the {Upsilon}(4S) resonance with the BABAR detector at the PEP-II e{sup +}e{sup -} storage rings. Events are tagged by fully reconstructing one of the B mesons in a hadronic decay mode. We measure the relative branching fraction {Beta}({bar B} {yields} {Lambda}{sub c}{sup +} X{ell}{sup -}{bar {nu}}{sub {ell}})/{Beta}({bar B} {yields} {Lambda}{sub c}{sup +}/{bar {Lambda}}{sub c}{sup -}X) = (3.2 {+-} 0.9{sub stat.} {+-} 0.9{sub syst.})%. The significance of the signal including the systematic uncertainty is 4.9 standard deviations.
lambda. production in e/sup +/e/sup -/ annihilations at 29 GeV
Abachi, S.; Baringer, P.; Beltrami, I.; Bylsma, B.G.; DeBonte, R.; Koltick, D.; Loeffler, F.J.; Low, E.H.; McIlwain, R.L.; Miller, D.H.
1986-05-01
This paper presents measurements of the inclusive production cross sections of ..lambda.. baryons in e/sup +/e/sup -/ annihilations at ..sqrt..s = 29 GeV. The data sample corresponds to an integrated luminosity of 256 pb/sup -1/ collected with the High Resolution Spectrometer at PEP. Comparisons are made to the predictions of the Lund model. The data are well described using a strange diquark suppression parameter, (us/ud)/(s/d), of 0.89 +- 0.10/sub -0.16//sup +0.56/, and the measured ..lambda../sub c/ ..-->.. ..lambda.. + X branching ratio of 23 +- 10%. No polarization is observed in the ..lambda.. decays. 17 refs., 5 figs.
Observation of B{sup -}{yields}p{Lambda}D{sup 0} at Belle
Chen, P.; Wang, M.-Z.; Chang, P.; Chao, Y.; Hou, W.-S.; Hsiung, Y. B.; Liu, Y.; Shiu, J.-G.; Adachi, I.; Haba, J.; Hara, T.; Itoh, R.; Iwasaki, Y.; Katayama, N.; Kichimi, H.; Nakao, M.; Nishida, S.; Sakai, Y.; Uehara, S.; Uno, S.
2011-10-01
We study B{sup -} meson decays to p{Lambda}D{sup (*)0} final states using a sample of 657x10{sup 6}BB events collected at the {Upsilon}(4S) resonance with the Belle detector at the KEKB asymmetric-energy e{sup +}e{sup -} collider. The observed branching fraction for B{sup -}{yields}p{Lambda}D{sup 0} is (1.43{sub -0.25}{sup +0.28}{+-}0.18)x10{sup -5} with a significance of 8.1 standard deviations, where the uncertainties are statistical and systematic, respectively. Most of the signal events have the p{Lambda} mass peaking near threshold. No significant signal is observed for B{sup -}{yields}p{Lambda}D{sup *0} and the corresponding upper limit on the branching fraction is 4.8x10{sup -5} at the 90% confidence level.
Accelerator system and method of accelerating particles
NASA Technical Reports Server (NTRS)
Wirz, Richard E. (Inventor)
2010-01-01
An accelerator system and method that utilize dust as the primary mass flux for generating thrust are provided. The accelerator system can include an accelerator capable of operating in a self-neutralizing mode and having a discharge chamber and at least one ionizer capable of charging dust particles. The system can also include a dust particle feeder that is capable of introducing the dust particles into the accelerator. By applying a pulsed positive and negative charge voltage to the accelerator, the charged dust particles can be accelerated thereby generating thrust and neutralizing the accelerator system.
Spectroscopic studies on lambda cro protein-DNA interactions.
Torigoe, C; Kidokoro, S; Takimoto, M; Kyogoku, Y; Wada, A
1991-06-20
Spectroscopic (circular dichroism and fluorescence) and thermodynamic studies were conducted on lambda Cro-DNA interactions. Some base substitutions were introduced to the operator and the effects on the conformation of the complex and thermodynamic parameters for dissociation of the complex were examined. It was found that, (1) in the specific binding of Cro with DNA which has a (pseudo) consensus sequence, DNA is overwound, while in non-specific binding it is unchanged, or rather unwound; (2) substitution of central base-pairs or the introduction of a mismatched base-pair at the center of the operator reduces the extent of DNA conformational change on Cro binding and lessens the stability of the Cro-DNA complex, even though there is apparently no direct interaction between Cro and DNA at these positions; (3) stability of the complex increases with the degree of DNA conformational change of the same type during binding; (4) in some cases of specific binding, there are three states in the dissociation of the complex as observed by salt titration: two conformational states for the complex depending on salt concentration and, in non-specific binding, dissociation is a two-state transition; (5) the number of ions involved in interactions between Cro and 17 base-pair DNA is about 7.7 for NaCl titrations; (6) dissociation free energy prediction of the Cro-DNA complex by simple addition of the dissociation free energy change of a single base-pair substitution agrees with our experimental results when DNA overwinding occurs during binding, i.e. in specific binding.
Structure and diversity of Mexican axolotl lambda light chains.
André, S; Guillet, F; Charlemagne, J; Fellah, J S
2000-11-01
We report here the structure of cDNA clones encoding axolotl light chains of the lambda type. A single IGLC gene and eight different potential IGLV genes belonging to four different families were detected. The axolotl Cgamma domain has several residues or stretches of residues that are typically conserved in mammalian, avian, and Xenopus Cgamma, but the KATLVCL stretch, which is well conserved in the Cgamma and T-cell receptor Cbeta domains of many vertebrate species, is not well conserved. All axolotl Vgamma sequences closely match several human and Xenopus Vgamma-like sequences and, although the axolotl Cgamma and Vgamma sequences are very like their tetrapod homologues, they are not closely related to nontetrapod L chains. Southern blot experiments suggested the presence of a single IGLC gene and of a limited number of IGLV genes, and analysis of IGLV-J junctions clearly indicated that at least three of the IGLJ segments can associate with IGLV1, IGLV2, or IGLV3 subgroup genes. The overall diversity of the axolotl Vgamma CDR3 junctions seems to be of the same order as that of mammalian Vgamma chains. However, a single IGLV4 segment was found among the 45 cDNAs analyzed. This suggests that the axolotl IGL locus may have a canonical tandem structure, like the mammalian IGK or IGH loci. Immunofluorescence, immunoblotting, and microsequencing experiments strongly suggested that most, if not all L chains are of the gamma type. This may explain in part the poor humoral response of the axolotl. PMID:11132150
Lambda and Antilambda Polarization in Proton-Proton Interactions from Sqrt. S = 31 TO 62 GEV.
NASA Astrophysics Data System (ADS)
Sherwood, Peter
This thesis presents measurements of Lambda^0, |Lambda ^0, and Sigma^0 production made using experiment R608 at the CERN ISR. The Lambda^0 cross sections have been measured in the range 0.20 < x _{rm F}< 0.96 and for p _{rm t} up to 2.2 GeV/c. The invariant cross section, E*d^3sigma /dp^3, is presented in x _{rm F} bins, plotted against p_{rm t}^2 . The function Aexp(-(bp _{rm t}^2 + cp _{rm t}^4)) was found to be a good fit to the data. The cross section was integrated with respect to p_{rm t} ^2 to obtain the x_{ rm F} dependence. The Lambda ^0 shows a rapid fall-off with x _{rm F} up to x_ {rm F}~ 0.4, and thereafter exhibits a small decline to zero at x_{ rm F}~ 1, as is typical for baryons produced in proton fragmentation processes. The |Lambda^0 cross section was measured in the region 0.2 < x_{rm F}< 0.5. The invariant cross section was found to be well described by the function Aexp(-bp _{rm t}^2). Unlike the Lambda^0, the |Lambda^0 cross section falls rapidly with x_{rm F}. The Sigma^0 cross section was measured in the region 0.5 < p_{rm t}< 1.2 GeV/c and 0.3 < x_{rm F}< 0.7. In this region, the Lambda ^0/Sigma^0 ratio is 0.376 +/- 0.044. The Sigma^0 is thus the dominant contributor to non-direct Lambda^0 production. The Lambda^0 polarization was measured as function of surds for 31
FY04 IRAD-funded GSFC Lambda Network (L-Net) Web Pages and Related Presentations
NASA Technical Reports Server (NTRS)
Gary, J. Patrick
2005-01-01
This presentation discusses the advances in Networking Technology combining the Global Lambda Integrated Facility (GLIF) cooperation with the National Lambda Rail (NLR) implementation. It also focuses on New NASA science needing Gigbit per second networks (Gbps) with coordinated Earth Observing Program, hurricane predictions, global aerosols, remote viewing and manipulation of large Earth Science Data Sets, integration of laser and radar topographic data with land cover data.
Properties of the bound {Lambda}({Sigma}){ital NN} system and hyperon-nucleon interactions
Miyagawa, K.; Kamada, H.; Gloeckle, W.; Stoks, V.
1995-06-01
The Faddeev equations for the hypertriton are solved precisely using the Nijmegen hyperon-nucleon and realistic {ital NN} interactions. The hypertriton turns out to be bound at the experimental value. Thereby the {Lambda}-{Sigma} conversion is crucial. States of the {Lambda}({Sigma}){ital NN} system with quantum numbers ({ital T},{ital J}) different from (0,1/2) are not bound. We visualized properties of the hypertriton wave function in various ways.
PREFACE: Progress in the ITER Physics Basis
NASA Astrophysics Data System (ADS)
Ikeda, K.
2007-06-01
I would firstly like to congratulate all who have contributed to the preparation of the `Progress in the ITER Physics Basis' (PIPB) on its publication and express my deep appreciation of the hard work and commitment of the many scientists involved. With the signing of the ITER Joint Implementing Agreement in November 2006, the ITER Members have now established the framework for construction of the project, and the ITER Organization has begun work at Cadarache. The review of recent progress in the physics basis for burning plasma experiments encompassed by the PIPB will be a valuable resource for the project and, in particular, for the current Design Review. The ITER design has been derived from a physics basis developed through experimental, modelling and theoretical work on the properties of tokamak plasmas and, in particular, on studies of burning plasma physics. The `ITER Physics Basis' (IPB), published in 1999, has been the reference for the projection methodologies for the design of ITER, but the IPB also highlighted several key issues which needed to be resolved to provide a robust basis for ITER operation. In the intervening period scientists of the ITER Participant Teams have addressed these issues intensively. The International Tokamak Physics Activity (ITPA) has provided an excellent forum for scientists involved in these studies, focusing their work on the high priority physics issues for ITER. Significant progress has been made in many of the issues identified in the IPB and this progress is discussed in depth in the PIPB. In this respect, the publication of the PIPB symbolizes the strong interest and enthusiasm of the plasma physics community for the success of the ITER project, which we all recognize as one of the great scientific challenges of the 21st century. I wish to emphasize my appreciation of the work of the ITPA Coordinating Committee members, who are listed below. Their support and encouragement for the preparation of the PIPB were
A cII-dependent promoter is located within the Q gene of bacteriophage lambda.
Hoopes, B C; McClure, W R
1985-05-01
We have found a cII-dependent promoter, PaQ, within the Q gene of bacteriophage lambda. Transcription experiments and abortive initiation assays performed in vitro showed that the promoter strength and the cII affinity of PaQ were comparable to the other cII-dependent lambda promoters, PE and PI. The location and leftward direction of PaQ suggests a possible role in the delay of lambda late-gene expression by cII protein, a phenomenon that has been called cII-dependent inhibition. We have constructed a promoter down mutation, paq-1, by changing a single base pair in the putative cII binding site of the promoter by oligonucleotide site-directed mutagenesis. The paq-1 mutant promoter required about 4-fold higher cII concentrations for maximal activation compared to the wild-type PaQ. We tested the hypothesis that PaQ is responsible in part for the delay of lambda late-gene expression by recombining the paq-1 mutation into a phage showing severe cII-dependent inhibition. We found that the paq-1 mutation relieved the cII-dependent growth defect of this phage. The paq-1 mutation (in combination with lambda cI857) resulted in a clear-plaque phenotype at the permissive temperature of 32 degrees C. The role of the PaQ-initiated antisense transcript in the control of lambda development is discussed.
Comparison of Iterative and Non-Iterative Strain-Gage Balance Load Calculation Methods
NASA Technical Reports Server (NTRS)
Ulbrich, N.
2010-01-01
The accuracy of iterative and non-iterative strain-gage balance load calculation methods was compared using data from the calibration of a force balance. Two iterative and one non-iterative method were investigated. In addition, transformations were applied to balance loads in order to process the calibration data in both direct read and force balance format. NASA's regression model optimization tool BALFIT was used to generate optimized regression models of the calibration data for each of the three load calculation methods. This approach made sure that the selected regression models met strict statistical quality requirements. The comparison of the standard deviation of the load residuals showed that the first iterative method may be applied to data in both the direct read and force balance format. The second iterative method, on the other hand, implicitly assumes that the primary gage sensitivities of all balance gages exist. Therefore, the second iterative method only works if the given balance data is processed in force balance format. The calibration data set was also processed using the non-iterative method. Standard deviations of the load residuals for the three load calculation methods were compared. Overall, the standard deviations show very good agreement. The load prediction accuracies of the three methods appear to be compatible as long as regression models used to analyze the calibration data meet strict statistical quality requirements. Recent improvements of the regression model optimization tool BALFIT are also discussed in the paper.
Current status of the ITER MSE diagnostic
NASA Astrophysics Data System (ADS)
Yuh, Howard; Levinton, F.; La Fleur, H.; Foley, E.; Feder, R.; Zakharov, L.
2013-10-01
The U.S. is providing ITER with a Motional Stark Effect (MSE) diagnostic to provide a measurement to guide reconstructions of the plasma q-profile. The diagnostic design has gone through many iterations, driven primarily by the evolution of the ITER port plug design and the steering of the heating beams. The present two port, three view design viewing both heating beams and the DNB has recently passed a conceptual design review at the IO. The traditional line polarization (MSE-LP) technique employed on many devices around the world faces many challenges in ITER, including strong background light and mirror degradation. To mitigate these effects, a multi-wavelength polarimeter and high resolution spectrometer will be used to subtract polarized background, while retroreflecting polarizers will provide mirror calibration concurrent with MSE-LP measurements. However, without a proven plasma-facing mirror cleaning technique, inherent risks to MSE-LP remain. The high field and high beam energy on ITER offers optimal conditions for a spectroscopic measurement of the electric field using line splitting (MSE-LS), a technique which does not depend on mirror polarization properties. The current design is presented with a roadmap of the R&D needed to address remaining challenges. This work is supported by DOE contracts S009627-R and S012380-F.
Iterative scatter correction based on artifact assessment
NASA Astrophysics Data System (ADS)
Wiegert, Jens; Hohmann, Steffen; Bertram, Matthias
2008-03-01
In this paper we propose a novel scatter correction methodology for X-ray based cone-beam CT that allows to combine the advantages of projection-based and volume-based correction approaches. The basic idea is to use a potentially non-optimal projection-based scatter correction method and to iteratively optimize its performance by repeatedly assessing remaining scatter-induced artifacts in intermediately reconstructed volumes. The novel approach exploits the fact that due to the flatness of the scatter-background, compensation itself is most easily performed in the projection-domain, while the scatter-induced artifacts can be better observed in the reconstructed volume. The presented method foresees to evaluate the scatter correction efficiency after each iteration by means of a quantitative measure characterizing the amount of residual cupping and to adjust the parameters of the projection-based scatter correction for the next iteration accordingly. The potential of this iterative scatter correction approach is demonstrated using voxelized Monte Carlo scatter simulations as ground truth. Using the proposed iterative scatter correction method, remarkable scatter correction performance was achieved both using simple parametric heuristic techniques as well as by optimizing previously published scatter estimation schemes. For the human head, scatter induced artifacts were reduced from initially 148 HU to less than 8.1 HU to 9.1 HU for different studied methods, corresponding to an artifact reduction exceeding 93%.
ITER Experts' meeting on density limits
Borrass, K.; Igitkhanov, Y.L.; Uckan, N.A.
1989-12-01
The necessity of achieving a prescribed wall load or fusion power essentially determines the plasma pressure in a device like ITER. The range of operation densities and temperatures compatible with this condition is constrained by the problems of power exhaust and the disruptive density limit. The maximum allowable heat loads on the divertor plates and the maximum allowable sheath edge temperature practically impose a lower limit on the operating densities, whereas the disruptive density limit imposes an upper limit. For most of the density limit scalings proposed in the past an overlap of the two constraints or at best a very narrow accessible density range is predicted for ITER. Improved understanding of the underlying mechanisms is therefore a crucial issue in order to provide a more reliable basis for extrapolation to ITER and to identify possible ways of alleviating the problem.
Re-starting an Arnoldi iteration
Lehoucq, R.B.
1996-12-31
The Arnoldi iteration is an efficient procedure for approximating a subset of the eigensystem of a large sparse n x n matrix A. The iteration produces a partial orthogonal reduction of A into an upper Hessenberg matrix H{sub m} of order m. The eigenvalues of this small matrix H{sub m} are used to approximate a subset of the eigenvalues of the large matrix A. The eigenvalues of H{sub m} improve as estimates to those of A as m increases. Unfortunately, so does the cost and storage of the reduction. The idea of re-starting the Arnoldi iteration is motivated by the prohibitive cost associated with building a large factorization.
Translating relational queries into iterative programs
Freytag, J.C.
1987-01-01
This book investigates the problem of translating relational queries into iterative programs using methods and techniques from the areas of functional programming and program transformation. The first part presents two algorithms which generate iterative programs from algebra-based query specifications. While the first algorithm is based on the transformation of recursive programs, the second uses functional expressions to generate the final iterative form. In the second part the same techniques generate efficient programs for the evaluation of aggregate functions in relational database systems. In several steps, programs which perform aggregation after sorting, are transformed into programs which perform aggregation while sorting. The third part then investigates the Lisp-dialect T as a possible implementation language for database systems.
Lousteau, D.C.
1994-09-01
The overall programmatic objective, as defined in the ITER Engineering Design Activities (EDA) Agreement, is to demonstrate the scientific and technological feasibility of fusion energy for peaceful purposes. The ITER EDA Phase, due to last until July 1998, will encompass the design of the device and its auxiliary systems and facilities, including the preparation of engineering drawings. The EDA also incorporates validating research and development (R&D) work, including the development and testing of key components. The purpose of this paper is to review the status of the design, as it has been developed so far, emphasizing the design and integration of those components contained within the vacuum vessel of the ITER device. The components included in the in-vessel systems are divertor and first wall; blanket and shield; plasma heating, fueling, and vacuum pumping equipment; and remote handling equipment.
Measurement of heat load density profile on acceleration grid in MeV-class negative ion accelerator.
Hiratsuka, Junichi; Hanada, Masaya; Kojima, Atsushi; Umeda, Naotaka; Kashiwagi, Mieko; Miyamoto, Kenji; Yoshida, Masafumi; Nishikiori, Ryo; Ichikawa, Masahiro; Watanabe, Kazuhiro; Tobari, Hiroyuki
2016-02-01
To understand the physics of the negative ion extraction/acceleration, the heat load density profile on the acceleration grid has been firstly measured in the ITER prototype accelerator where the negative ions are accelerated to 1 MeV with five acceleration stages. In order to clarify the profile, the peripheries around the apertures on the acceleration grid were separated into thermally insulated 34 blocks with thermocouples. The spatial resolution is as low as 3 mm and small enough to measure the tail of the beam profile with a beam diameter of ∼16 mm. It was found that there were two peaks of heat load density around the aperture. These two peaks were also clarified to be caused by the intercepted negative ions and secondary electrons from detailed investigation by changing the beam optics and gas density profile. This is the first experimental result, which is useful to understand the trajectories of these particles. PMID:26932019
Global Asymptotic Behavior of Iterative Implicit Schemes
NASA Technical Reports Server (NTRS)
Yee, H. C.; Sweby, P. K.
1994-01-01
The global asymptotic nonlinear behavior of some standard iterative procedures in solving nonlinear systems of algebraic equations arising from four implicit linear multistep methods (LMMs) in discretizing three models of 2 x 2 systems of first-order autonomous nonlinear ordinary differential equations (ODEs) is analyzed using the theory of dynamical systems. The iterative procedures include simple iteration and full and modified Newton iterations. The results are compared with standard Runge-Kutta explicit methods, a noniterative implicit procedure, and the Newton method of solving the steady part of the ODEs. Studies showed that aside from exhibiting spurious asymptotes, all of the four implicit LMMs can change the type and stability of the steady states of the differential equations (DEs). They also exhibit a drastic distortion but less shrinkage of the basin of attraction of the true solution than standard nonLMM explicit methods. The simple iteration procedure exhibits behavior which is similar to standard nonLMM explicit methods except that spurious steady-state numerical solutions cannot occur. The numerical basins of attraction of the noniterative implicit procedure mimic more closely the basins of attraction of the DEs and are more efficient than the three iterative implicit procedures for the four implicit LMMs. Contrary to popular belief, the initial data using the Newton method of solving the steady part of the DEs may not have to be close to the exact steady state for convergence. These results can be used as an explanation for possible causes and cures of slow convergence and nonconvergence of steady-state numerical solutions when using an implicit LMM time-dependent approach in computational fluid dynamics.
Challenges and status of ITER conductor production
NASA Astrophysics Data System (ADS)
Devred, A.; Backbier, I.; Bessette, D.; Bevillard, G.; Gardner, M.; Jong, C.; Lillaz, F.; Mitchell, N.; Romano, G.; Vostner, A.
2014-04-01
Taking the relay of the large Hadron collider (LHC) at CERN, ITER has become the largest project in applied superconductivity. In addition to its technical complexity, ITER is also a management challenge as it relies on an unprecedented collaboration of seven partners, representing more than half of the world population, who provide 90% of the components as in-kind contributions. The ITER magnet system is one of the most sophisticated superconducting magnet systems ever designed, with an enormous stored energy of 51 GJ. It involves six of the ITER partners. The coils are wound from cable-in-conduit conductors (CICCs) made up of superconducting and copper strands assembled into a multistage cable, inserted into a conduit of butt-welded austenitic steel tubes. The conductors for the toroidal field (TF) and central solenoid (CS) coils require about 600 t of Nb3Sn strands while the poloidal field (PF) and correction coil (CC) and busbar conductors need around 275 t of Nb-Ti strands. The required amount of Nb3Sn strands far exceeds pre-existing industrial capacity and has called for a significant worldwide production scale up. The TF conductors are the first ITER components to be mass produced and are more than 50% complete. During its life time, the CS coil will have to sustain several tens of thousands of electromagnetic (EM) cycles to high current and field conditions, way beyond anything a large Nb3Sn coil has ever experienced. Following a comprehensive R&D program, a technical solution has been found for the CS conductor, which ensures stable performance versus EM and thermal cycling. Productions of PF, CC and busbar conductors are also underway. After an introduction to the ITER project and magnet system, we describe the ITER conductor procurements and the quality assurance/quality control programs that have been implemented to ensure production uniformity across numerous suppliers. Then, we provide examples of technical challenges that have been encountered and
Tracking Solar Events through Iterative Refinement
NASA Astrophysics Data System (ADS)
Kempton, D. J.; Angryk, R. A.
2015-11-01
In this paper, we combine two approaches to multiple-target tracking: the first is a hierarchical approach to iteratively growing track fragments across gaps in detections; the second is a network flow based optimization method for data association. The network flow based optimization method is utilized for data association in an iteratively growing manner. This process is applied to solar data, retrieved from the Heliophysics Event Knowledge base (HEK) and utilizes precomputed image parameter values. These precomputed image parameter values are used to compare visual similarity of detected events, to determine the best matching track fragment associations, which leads to a globally optimal track fragment association hypothesis.
Fatigue tests on the ITER PF jacket
NASA Astrophysics Data System (ADS)
Qin, Jinggang; Weiss, Klaus-Peter; Wu, Yu; Wu, Zhixiong; Li, Laifeng; Liu, Sheng
2012-10-01
This paper focuses on fatigue tests on the ITER Poloidal Field (PF) jacket made of 316L stainless steel material. During manufacture, the conductor will be compacted and spooled after cable insertion. Therefore, sample jackets were prepared under compaction, bending and straightening in order to simulate the status of PF conductor during manufacturing and winding. The fatigue properties of materials were measured at T < 7 K, including S-N and fatigue crack growth rate (FCGR). The testing results show that the present Chinese PF jacket has good fatigue properties, which conclude that the results are accordant with the requirements of ITER.
Iterative method for generating correlated binary sequences
NASA Astrophysics Data System (ADS)
Usatenko, O. V.; Melnik, S. S.; Apostolov, S. S.; Makarov, N. M.; Krokhin, A. A.
2014-11-01
We propose an efficient iterative method for generating random correlated binary sequences with a prescribed correlation function. The method is based on consecutive linear modulations of an initially uncorrelated sequence into a correlated one. Each step of modulation increases the correlations until the desired level has been reached. The robustness and efficiency of the proposed algorithm are tested by generating sequences with inverse power-law correlations. The substantial increase in the strength of correlation in the iterative method with respect to single-step filtering generation is shown for all studied correlation functions. Our results can be used for design of disordered superlattices, waveguides, and surfaces with selective transport properties.
A novel resistance iterative algorithm for CCOS
NASA Astrophysics Data System (ADS)
Zheng, Ligong; Zhang, Xuejun
2006-08-01
CCOS (Computer Control Optical Surfacing) technology is widely used for making aspheric mirrors. For most manufacturers, dwell time algorithm is usually employed to determine the route and dwell time of the small tools to converge the errors. In this article, a novel damp iterative algorithm is proposed. We chose revolutions of the small tool instead of dwell time to determine fabrication stratagem. By using resistance iterative algorithm, we can solve these revolutions. Several mirrors have been manufactured by this method, all of them have fulfilled the demand of the designers, a 1m aspheric mirror was finished within 3 months.
Stability of a radiative mantle in ITER
Mahdavi, M.A.; Staebler, G.M.; Wood, R.D.; Whyte, D.G.; West, W.P.
1996-12-01
We report results of a study to evaluate the efficacy of various impurities for heat dispersal by a radiative mantle and radiative divertor(including SOL). We have derived a stability criterion for the mantle radiation which favors low Z impurities and low ratios of edge to core thermal conductivities. Since on the other hand the relative strength of boundary line radiation to core bremsstrahlung favors high Z impurities, we find that for the ITER physics phase argon is the best gaseous impurity for mantle radiation. For the engineering phase of ITER, more detailed analysis is needed to select between krypton and argon.
Scheduling and rescheduling with iterative repair
NASA Technical Reports Server (NTRS)
Zweben, Monte; Davis, Eugene; Daun, Brian; Deale, Michael
1992-01-01
This paper describes the GERRY scheduling and rescheduling system being applied to coordinate Space Shuttle Ground Processing. The system uses constraint-based iterative repair, a technique that starts with a complete but possibly flawed schedule and iteratively improves it by using constraint knowledge within repair heuristics. In this paper we explore the tradeoff between the informedness and the computational cost of several repair heuristics. We show empirically that some knowledge can greatly improve the convergence speed of a repair-based system, but that too much knowledge, such as the knowledge embodied within the MIN-CONFLICTS lookahead heuristic, can overwhelm a system and result in degraded performance.
Tritium Pumps for ITER Roughing System
Antipenkov, Alexander; Day, Christian; Mack, August; Wagner, Robert; Laesser, Rainer
2005-07-15
The ITER roughing system provides for both the initial pump-down of the vessel itself and the regular pump-out of the batch-regenerating cryopumps. This system must have a large pumping speed and cope with the radioactive gas tritium at the same time. The present paper shall highlight the results of the ITER roughing train optimization, discuss the modification of a Roots pump for tritium, and present the results of a ferrofluidic seal test and the first tests of a tailor-made tritium-proof Roots pump with inactive gases.
Townsend, Catherine L.; Laffy, Julie M. J.; Wu, Yu-Chang Bryan; Silva O’Hare, Joselli; Martin, Victoria; Kipling, David; Fraternali, Franca; Dunn-Walters, Deborah K.
2016-01-01
Antibody variable regions are composed of a heavy and a light chain, and in humans, there are two light chain isotypes: kappa and lambda. Despite their importance in receptor editing, the light chain is often overlooked in the antibody literature, with the focus being on the heavy chain complementarity-determining region (CDR)-H3 region. In this paper, we set out to investigate the physicochemical and structural differences between human kappa and lambda light chain CDR regions. We constructed a dataset containing over 29,000 light chain variable region sequences from IgM-transcribing, newly formed B cells isolated from human bone marrow and peripheral blood. We also used a published human naïve dataset to investigate the CDR-H3 properties of heavy chains paired with kappa and lambda light chains and probed the Protein Data Bank to investigate the structural differences between kappa and lambda antibody CDR regions. We found that kappa and lambda light chains have very different CDR physicochemical and structural properties, whereas the heavy chains with which they are paired do not differ significantly. We also observed that the mean CDR3 N nucleotide addition in the kappa, lambda, and heavy chain gene rearrangements are correlated within donors but can differ between donors. This indicates that terminal deoxynucleotidyl transferase may work with differing efficiencies between different people but the same efficiency in the different classes of immunoglobulin chain within one person. We have observed large differences in the physicochemical and structural properties of kappa and lambda light chain CDR regions. This may reflect different roles in the humoral immune response. PMID:27729912
RAMAN SCATTERED He II {lambda}4332 IN THE SYMBIOTIC STAR V1016 CYGNI
Lee, Hee-Won
2012-05-10
Raman scattering of He II line photons with atomic hydrogen is important in studying the mass loss processes in many symbiotic stars and a number of young planetary nebulae. We calculate the scattering cross sections and branching ratios associated with the Raman scattered He II {lambda}4332 feature formed through inelastic scattering of He II {lambda}949 with a hydrogen atom. At the line center of He II {lambda}949, the total scattering cross section is computed to be {sigma}{sub tot} = 2.5 Multiplication-Sign 10{sup -22} cm{sup 2}, and the branching ratio into the level 2s is 0.12. We also present a high-resolution spectrum of the symbiotic star V1016 Cygni obtained with the 1.8 m telescope at Mt. Bohyun to investigate the Raman scattering origin of the broad feature blueward of He II {lambda}4338. Based on the atomic calculation, we perform Monte Carlo calculations for the line formation. The scattering region is assumed to be a part of a uniform spherical shell that subtends a solid angle {Delta}{Omega} = {pi} steradian with a neutral column density N{sub HI} = 1.0 x 10{sup 21} cm{sup -2}. By adding a far-UV continuum around He II {lambda}949 normalized by the equivalent width of He II {lambda}949 to be 2.3 Angstrom-Sign , we obtain a good fit for both the Raman scattered He II {lambda}4332 and the broad wings around H{gamma}. Our analysis of the Raman feature blueward of H{gamma} in V1016 Cyg is consistent with the previous study of the Raman features blueward of H{alpha} and H{beta} by Jung and Lee.
The degenerate spin-flip doublet (3{sup +}/2,5{sup +}/2) of {sub {lambda}}{sup 9}Be
Shoeb, Mohammad; Sonika
2009-05-15
The energy of the degenerate doublet (3{sup +}/2,5{sup +}/2) of {sub {lambda}}{sup 9}Be, treating it as a partially nine-body system in the {lambda}{alpha}{alpha} cluster model, has been calculated in the variational Monte Carlo framework. A simplified treatment, with the central two-body Urbana type {lambda}N and the three-body dispersive and two-pion exchange {lambda}NN forces along with the central two- and three-body correlations, is found to be adequate in explaining the energy of observed {gamma}-ray transition from the excited degenerate doublet to the ground state. The hypernucleus {sub {lambda}}{sup 9}Be is highly deformed and has an oblate shape in the excited state. The results of the present work are consistent with the earlier three-body cluster model analyzes of {sub {lambda}}{sup 9}Be.
Iterative solution of the Helmholtz equation
Larsson, E.; Otto, K.
1996-12-31
We have shown that the numerical solution of the two-dimensional Helmholtz equation can be obtained in a very efficient way by using a preconditioned iterative method. We discretize the equation with second-order accurate finite difference operators and take special care to obtain non-reflecting boundary conditions. We solve the large, sparse system of equations that arises with the preconditioned restarted GMRES iteration. The preconditioner is of {open_quotes}fast Poisson type{close_quotes}, and is derived as a direct solver for a modified PDE problem.The arithmetic complexity for the preconditioner is O(n log{sub 2} n), where n is the number of grid points. As a test problem we use the propagation of sound waves in water in a duct with curved bottom. Numerical experiments show that the preconditioned iterative method is very efficient for this type of problem. The convergence rate does not decrease dramatically when the frequency increases. Compared to banded Gaussian elimination, which is a standard solution method for this type of problems, the iterative method shows significant gain in both storage requirement and arithmetic complexity. Furthermore, the relative gain increases when the frequency increases.
Constructing Easily Iterated Functions with Interesting Properties
ERIC Educational Resources Information Center
Sprows, David J.
2009-01-01
A number of schools have recently introduced new courses dealing with various aspects of iteration theory or at least have found ways of including topics such as chaos and fractals in existing courses. In this note, we will consider a family of functions whose members are especially well suited to illustrate many of the concepts involved in these…
First mirrors for diagnostic systems of ITER
NASA Astrophysics Data System (ADS)
Litnovsky, A.; Voitsenya, V. S.; Costley, A.; Donné, A. J. H.; SWG on First Mirrors of the ITPA Topical Group on Diagnostics
2007-08-01
The majority of optical diagnostics presently foreseen for ITER will implement in-vessel metallic mirrors as plasma-viewing components. Mirrors are used for the observation of the plasma radiation in a very wide wavelength range: from about 1 nm up to a few mm. In the hostile ITER environment, mirrors are subject to erosion, deposition, particle implantation and other adverse effects which will change their optical properties, affecting the entire performance of the respective diagnostic systems. The Specialists Working Group (SWG) on first mirrors was established under the wings of the International Tokamak Physics Activity (ITPA) Topical Group (TG) on Diagnostics to coordinate and guide the investigations on diagnostic mirrors towards the development of optimal, robust and durable solutions for ITER diagnostic systems. The results of tests of various ITER-candidate mirror materials, performed in Tore-Supra, TEXTOR, DIII-D, TCV, T-10, TRIAM-1M and LHD under various plasma conditions, as well as an overview of laboratory investigations of mirror performance and mirror cleaning techniques are presented in the paper. The current tasks in the R&D of diagnostic mirrors will be addressed.
Asymptotic iteration approach to supersymmetric bistable potentials
NASA Astrophysics Data System (ADS)
Ciftci, H.; Özer, O.; P., Roy
2012-01-01
We examine quasi exactly solvable bistable potentials and their supersymmetric partners within the framework of the asymptotic iteration method (AIM). It is shown that the AIM produces excellent approximate spectra and that sometimes it is found to be more useful to use the partner potential for computation. We also discuss the direct application of the AIM to the Fokker—Planck equation.
Matched filter based iterative adaptive approach
NASA Astrophysics Data System (ADS)
Nepal, Ramesh; Zhang, Yan Rockee; Li, Zhengzheng; Blake, William
2016-05-01
Matched Filter sidelobes from diversified LPI waveform design and sensor resolution are two important considerations in radars and active sensors in general. Matched Filter sidelobes can potentially mask weaker targets, and low sensor resolution not only causes a high margin of error but also limits sensing in target-rich environment/ sector. The improvement in those factors, in part, concern with the transmitted waveform and consequently pulse compression techniques. An adaptive pulse compression algorithm is hence desired that can mitigate the aforementioned limitations. A new Matched Filter based Iterative Adaptive Approach, MF-IAA, as an extension to traditional Iterative Adaptive Approach, IAA, has been developed. MF-IAA takes its input as the Matched Filter output. The motivation here is to facilitate implementation of Iterative Adaptive Approach without disrupting the processing chain of traditional Matched Filter. Similar to IAA, MF-IAA is a user parameter free, iterative, weighted least square based spectral identification algorithm. This work focuses on the implementation of MF-IAA. The feasibility of MF-IAA is studied using a realistic airborne radar simulator as well as actual measured airborne radar data. The performance of MF-IAA is measured with different test waveforms, and different Signal-to-Noise (SNR) levels. In addition, Range-Doppler super-resolution using MF-IAA is investigated. Sidelobe reduction as well as super-resolution enhancement is validated. The robustness of MF-IAA with respect to different LPI waveforms and SNR levels is also demonstrated.
Iteration of Complex Functions and Newton's Method
ERIC Educational Resources Information Center
Dwyer, Jerry; Barnard, Roger; Cook, David; Corte, Jennifer
2009-01-01
This paper discusses some common iterations of complex functions. The presentation is such that similar processes can easily be implemented and understood by undergraduate students. The aim is to illustrate some of the beauty of complex dynamics in an informal setting, while providing a couple of results that are not otherwise readily available in…
Solving Differential Equations Using Modified Picard Iteration
ERIC Educational Resources Information Center
Robin, W. A.
2010-01-01
Many classes of differential equations are shown to be open to solution through a method involving a combination of a direct integration approach with suitably modified Picard iterative procedures. The classes of differential equations considered include typical initial value, boundary value and eigenvalue problems arising in physics and…
ITER faces further five-year delay
NASA Astrophysics Data System (ADS)
Clery, Daniel
2016-06-01
The €14bn ITER fusion reactor currently under construction in Cadarache, France, will require an additional cash injection of €4.6bn if it is to start up in 2025 - a target date that is already five years later than currently scheduled.
Microtearing Instability In The ITER Pedestal
Wong, K. L.; Mikkelsen, D. R.; Rewoldt, G. M.; Budny, R.
2010-12-01
Unstable microtearing modes are discovered by the GS2 gyrokinetic siimulation code, in the pedestal region of a simulated ITER H-mode plasma with approximately 400 WM DT fusion power. Existing nonlinear theory indicates that these instabilities should produce stochastic magnetic fields and broaden the pedestal. The resulted electron thermal conductivity is estimated and the implications of these findings are discussed.
Iteration and Anxiety in Mathematical Literature
ERIC Educational Resources Information Center
Capezzi, Rita; Kinsey, L. Christine
2016-01-01
We describe our experiences in team-teaching an honors seminar on mathematics and literature. We focus particularly on two of the texts we read: Georges Perec's "How to Ask Your Boss for a Raise" and Alain Robbe-Grillet's "Jealousy," both of which make use of iterative structures.
An {alpha}-cluster model for {sub {Lambda}}{sup 9}Be spectroscopy
Filikhin, I. N. Suslov, V. M.; Vlahovic, B.
2013-03-15
An {alpha}-cluster model is applied to study low-lying spectrum of the {sub {Lambda}}{sup 9}Be hypernucleus. The three-body {alpha}{alpha}{Lambda} problem is numerically solved by the Faddeev equations in configuration space using phenomenological pair potentials. We found a set of the potentials that reproduces experimental data for the ground state (1/2{sup +}) binding energy and excitation energy of the 5/2{sup +} and 3/2{sup +} states, simultaneously. This set includes the Ali-Bodmer potential of the version 'e' for {alpha}{alpha} and modified Tang-Herndon potential for {alpha}{Lambda} interactions. The spin-orbit {alpha}{Lambda} interaction is given by modified Scheerbaum potential. Low-lying energy levels are evaluated applying a variant of the analytical continuation method in the coupling constant. It is shown that the spectral properties of {sub {Lambda}}{sup 9}Be can be classified as an analog of {sup 9}Be spectrum with the exception of several 'genuine hypernuclear states'. This agrees qualitatively with previous studies. The results are compared with experimental data and new interpretation of the spectral structure is discussed.
Partial FI gene-independence of lambda-21 hybrid phages specifying chimeric terminases.
Feiss, M; Frackman, S; Momany, T
1988-11-01
The role of the FI gene in the life cycles of a series of lambda-21 hybrid phages that produce chimeric lambda-21 terminases has been examined. An isogenic series of FI+ and FI- derivatives of the hybrids was constructed, and the growth properties of the phages were examined. It was found that three of the four hybrids (hybrids 51, 67, and 33) are able to form plaques and produce a small burst in the absence of the FI gene product (gpFI), but each of the three phages is much healthier in the presence of gpFI. It is concluded that each of the three chimeric terminases is dependent on gpFI. The ability of the FI- hybrids to grow better than lambda FI- is postulated to be due to a minor qualitative or quantitative difference between the chimeric terminases and lambda terminase. The fourth hybrid (54), known from earlier work to produce an infirm terminase, is more dependent on gpFI than the other hybrids and lambda itself. PMID:2973176
Barbosa, Paulo R R; Michaud, J P; Rodrigues, Agna R S; Torres, Jorge B
2016-09-01
Insecticide resistance is usually associated with pests, but may also evolve in natural enemies. In this study, adult beetles of three distinct North American populations of Hippodamia convergens Guérin-Méneville, and the progeny of reciprocal crosses between the resistant and most susceptible population, were treated topically with varying concentrations of lambda-cyhalothrin and dicrotophos. In addition, the LD50s of both insecticides were applied in combination to resistant individuals. The developmental and reproductive performance of each population was assessed in the absence of insecticide exposure to compare baseline fitness. California and Kansas populations were susceptible to both materials, whereas Georgia (GA) beetles exhibited a resistance ratio (RR50) of 158 to lambda-cyhalothrin and 530 to dicrotophos. Inheritance of lambda-cyhalothrin resistance was X-linked, whereas inheritance of dicrotophos resistance was autosomal. Mortality of resistant beetles treated with a mixture of LD50s of both materials was twice that of those treated with lambda-cyhalothrin alone, but not significantly different from those receiving dicrotophos alone. Life history parameters were largely similar among populations, except that Georgia beetles had higher egg fertility relative to susceptible populations. We conclude that the high levels of resistance to lambda-cyhalothrin and dicrotophos in Georgia beetles reflect heavy loads of these insecticides in local environments, most likely the large acreage under intensive cotton cultivation. PMID:27266835
Lambda Station: Alternate network path forwarding for production SciDAC applications
Grigoriev, Maxim; Bobyshev, Andrey; Crawford, Matt; DeMar, Phil; Grigaliunas, Vyto; Moibenko, Alexander; Petravick, Don; Newman, Harvey; Steenberg, Conrad; Thomas, Michael; /Caltech
2007-09-01
The LHC era will start very soon, creating immense data volumes capable of demanding allocation of an entire network circuit for task-driven applications. Circuit-based alternate network paths are one solution to meeting the LHC high bandwidth network requirements. The Lambda Station project is aimed at addressing growing requirements for dynamic allocation of alternate network paths. Lambda Station facilitates the rerouting of designated traffic through site LAN infrastructure onto so-called 'high-impact' wide-area networks. The prototype Lambda Station developed with Service Oriented Architecture (SOA) approach in mind will be presented. Lambda Station has been successfully integrated into the production version of the Storage Resource Manager (SRM), and deployed at US CMS Tier1 center at Fermilab, as well as at US-CMS Tier-2 site at Caltech. This paper will discuss experiences using the prototype system with production SciDAC applications for data movement between Fermilab and Caltech. The architecture and design principles of the production version Lambda Station software, currently being implemented as Java based web services, will also be presented in this paper.
Control of bacteriophage lambda CII activity by bacteriophage and host functions.
Rattray, A; Altuvia, S; Mahajna, G; Oppenheim, A B; Gottesman, M
1984-01-01
We have studied the regulation of the lambda cII gene in vivo using cloned lambda fragments. Lambda N protein stimulated cII expression. Surprisingly, although very high cII protein levels were detected by gel electrophoresis, little cII protein activity, measured as stimulation of the lambda pI and pE promoters, was observed. The half-life of cII protein depended critically on its initial level. At low concentrations its half-life was as short as 1.5 min, whereas at high cII protein levels, it could be as long as 22 min. The Escherichia coli mutant ER437 directs lambda towards lysogeny; cII protein was more stable in this strain than in the wild type. On the other hand, although cyclic AMP is required for efficient lysogeny, it did not appear to influence the synthesis, stability, or activity of cII protein. Images PMID:6330032
Development of advanced inductive scenarios for ITER
NASA Astrophysics Data System (ADS)
Luce, T. C.; Challis, C. D.; Ide, S.; Joffrin, E.; Kamada, Y.; Politzer, P. A.; Schweinzer, J.; Sips, A. C. C.; Stober, J.; Giruzzi, G.; Kessel, C. E.; Murakami, M.; Na, Y.-S.; Park, J. M.; Polevoi, A. R.; Budny, R. V.; Citrin, J.; Garcia, J.; Hayashi, N.; Hobirk, J.; Hudson, B. F.; Imbeaux, F.; Isayama, A.; McDonald, D. C.; Nakano, T.; Oyama, N.; Parail, V. V.; Petrie, T. W.; Petty, C. C.; Suzuki, T.; Wade, M. R.; the ITPA Integrated Operation Scenario Topical Group Members; the ASDEX-Upgrade Team; the DIII-D Team; EFDA Contributors, JET; the JT-60U Team
2014-01-01
Since its inception in 2002, the International Tokamak Physics Activity topical group on Integrated Operational Scenarios (IOS) has coordinated experimental and modelling activity on the development of advanced inductive scenarios for applications in the ITER tokamak. The physics basis and the prospects for applications in ITER have been advanced significantly during that time, especially with respect to experimental results. The principal findings of this research activity are as follows. Inductive scenarios capable of higher normalized pressure (βN ⩾ 2.4) than the ITER baseline scenario (βN = 1.8) with normalized confinement at or above the standard H-mode scaling are well established under stationary conditions on the four largest diverted tokamaks (AUG, DIII-D, JET, JT-60U), demonstrated in a database of more than 500 plasmas from these tokamaks analysed here. The parameter range where high performance is achieved is broad in q95 and density normalized to the empirical density limit. MHD modes can play a key role in reaching stationary high performance, but also define the limits to achieved stability and confinement. Projection of performance in ITER from existing experiments uses empirical scalings and theory-based modelling. The status of the experimental validation of both approaches is summarized here. The database shows significant variation in the energy confinement normalized to standard H-mode confinement scalings, indicating the possible influence of additional physics variables absent from the scalings. Tests using the available information on rotation and the ratio of the electron and ion temperatures indicate neither of these variables in isolation can explain the variation in normalized confinement observed. Trends in the normalized confinement with the two dimensionless parameters that vary most from present-day experiments to ITER, gyroradius and collision frequency, are significant. Regression analysis on the multi-tokamak database has been
NASA Astrophysics Data System (ADS)
Tsuritani, Takehiro; Okamoto, Shuichi; Ogino, Nagao; Otani, Tomohiro; Tanaka, Hideaki
2004-10-01
This paper proposes an architecture of a next-generation Internet eXchange (IX) based on the Generalized Multi-Protocol Label Switching (GMPLS) technologies and the photonic cross-connect (PXC), hereafter referred to a Lambda-IX. At first, we investigate a basic Lambda-IX model where the PXC provides a GMPLS-controlled lambda label-switched path (LSP) to interconnect different ISPs' border routers. We verify that the proposed Lambda-IX model can achieve the lambda-based and resilient interconnection for the ISPs, thanks to the PXC's bit-rate insensitive operation as well as fast restoration operation. In addition, once GMPLS functionalities are introduced on the border routers as well as the PXC, very flexible interconnection can be achieved such as demand-based creation and deletion of lambda LSPs. Next, we initiatively demonstrate an experimental Lambda-IX using a PXC and IP/MPLS routers. A Lambda-LSP with OC-192 bandwidth can be successfully created by using the GMPLS RSVP-TE signaling protocol via a control plane, and an EGP session of Border Gateway Protocol 4 (BGP-4) can be established over the Lambda-LSP created between the GMPLS-enabled border routers via a data plane. We also evaluate the fault recovery operation in the case where such Lambda-IXs are consisted of several PXCs and demonstrate that the Lambda-LSP as well as the corresponding BGP session can be restored with a fast recovery time of less than 1s. Through these investigation and demonstration, it is revealed that the Lambda-IX can be put to practical use aiming at inter-exchanging a large traffic in a near future, while enriching the functions of IX.
Hesford, Andrew J.; Chew, Weng C.
2010-01-01
The distorted Born iterative method (DBIM) computes iterative solutions to nonlinear inverse scattering problems through successive linear approximations. By decomposing the scattered field into a superposition of scattering by an inhomogeneous background and by a material perturbation, large or high-contrast variations in medium properties can be imaged through iterations that are each subject to the distorted Born approximation. However, the need to repeatedly compute forward solutions still imposes a very heavy computational burden. To ameliorate this problem, the multilevel fast multipole algorithm (MLFMA) has been applied as a forward solver within the DBIM. The MLFMA computes forward solutions in linear time for volumetric scatterers. The typically regular distribution and shape of scattering elements in the inverse scattering problem allow the method to take advantage of data redundancy and reduce the computational demands of the normally expensive MLFMA setup. Additional benefits are gained by employing Kaczmarz-like iterations, where partial measurements are used to accelerate convergence. Numerical results demonstrate both the efficiency of the forward solver and the successful application of the inverse method to imaging problems with dimensions in the neighborhood of ten wavelengths. PMID:20707438
Benchmark of numerical tools simulating beam propagation and secondary particles in ITER NBI
NASA Astrophysics Data System (ADS)
Sartori, E.; Veltri, P.; Dlougach, E.; Hemsworth, R.; Serianni, G.; Singh, M.
2015-04-01
Injection of high energy beams of neutral particles is a method for plasma heating in fusion devices. The ITER injector, and its prototype MITICA (Megavolt ITER Injector and Concept Advancement), are large extrapolations from existing devices: therefore numerical modeling is needed to set thermo-mechanical requirements for all beam-facing components. As the power and charge deposition originates from several sources (primary beam, co-accelerated electrons, and secondary production by beam-gas, beam-surface, and electron-surface interaction), the beam propagation along the beam line is simulated by comprehensive 3D models. This paper presents a comparative study between two codes: BTR has been used for several years in the design of the ITER HNB/DNB components; SAMANTHA code was independently developed and includes additional phenomena, such as secondary particles generated by collision of beam particles with the background gas. The code comparison is valuable in the perspective of the upcoming experimental operations, in order to prepare a reliable numerical support to the interpretation of experimental measurements in the beam test facilities. The power density map calculated on the Electrostatic Residual Ion Dump (ERID) is the chosen benchmark, as it depends on the electric and magnetic fields as well as on the evolution of the beam species via interaction with the gas. Finally the paper shows additional results provided by SAMANTHA, like the secondary electrons produced by volume processes accelerated by the ERID fringe-field towards the Cryopumps.
Benchmark of numerical tools simulating beam propagation and secondary particles in ITER NBI
Sartori, E. Veltri, P.; Serianni, G.; Dlougach, E.; Hemsworth, R.; Singh, M.
2015-04-08
Injection of high energy beams of neutral particles is a method for plasma heating in fusion devices. The ITER injector, and its prototype MITICA (Megavolt ITER Injector and Concept Advancement), are large extrapolations from existing devices: therefore numerical modeling is needed to set thermo-mechanical requirements for all beam-facing components. As the power and charge deposition originates from several sources (primary beam, co-accelerated electrons, and secondary production by beam-gas, beam-surface, and electron-surface interaction), the beam propagation along the beam line is simulated by comprehensive 3D models. This paper presents a comparative study between two codes: BTR has been used for several years in the design of the ITER HNB/DNB components; SAMANTHA code was independently developed and includes additional phenomena, such as secondary particles generated by collision of beam particles with the background gas. The code comparison is valuable in the perspective of the upcoming experimental operations, in order to prepare a reliable numerical support to the interpretation of experimental measurements in the beam test facilities. The power density map calculated on the Electrostatic Residual Ion Dump (ERID) is the chosen benchmark, as it depends on the electric and magnetic fields as well as on the evolution of the beam species via interaction with the gas. Finally the paper shows additional results provided by SAMANTHA, like the secondary electrons produced by volume processes accelerated by the ERID fringe-field towards the Cryopumps.
Spectroscopic Research of Lambda Hypdernuclei at JLab Hall C
NASA Astrophysics Data System (ADS)
Gogami, T.; Achenbach, P.; Ahmidouch, A.; Albayrak, I.; Androic, D.; Asaturyan, A.; Asaturyan, R.; Ates, O.; Baturin, P.; Badui, R.; Boeglin, W.; Bono, J.; Brash, E.; Carter, P.; Chen, C.; Chiba, A.; Christy, E.; Dalton, M.; Danagoulian, S.; De Leo, R.; Doi, D.; Elaasar, M.; Ent, R.; Fujii, Y.; Furic, M.; Gabrielyan, M.; Gan, L.; Garibaldi, F.; Gaskell, D.; Gasparian, A.; Hashimoto, O.; Horn, T.; Hu, B.; Hungerford, Ed. V.; Jones, M.; Kanda, H.; Kaneta, M.; Kato, S.; Kawai, M.; Kawama, D.; Khanal, H.; Kohl, M.; Liyanage, A.; Luo, W.; Maeda, K.; Margaryan, A.; Markowitz, P.; Maruta, T.; Matsumura, A.; Maxwell, V.; Mkrtchyan, A.; Mkrtchyan, H.; Nagao, S.; Nakamura, S. N.; Narayan, A.; Neville, C.; Niculescu, G.; Niculescu, M. I.; Nunez, A.; Nuruzzaman; Okayasu, Y.; Petkovic, T.; Pochodzalla, J.; Qiu, X.; Reinhold, J.; Rodriguez, V. M.; Samanta, C.; Sawatzky, B.; Seva, T.; Shichijo, A.; Tadevosyan, V.; Tang, L.; Taniya, N.; Tsukada, K.; Veilleux, M.; Vulcan, W.; Wesselmann, F. R.; Wood, S. A.; Yamamoto, T.; Ya, L.; Ye, Z.; Yokota, K.; Yuan, L.; Zhamkochyan, S.; Zhu, L.
A Λ hyperon which has a strangeness can be bound in deep inside of a nucleus since a Λ does not suffer from the Pauli exclusion principle from nucleons. Thus, a Λ could be a useful tool to investigate inside of a nucleus. Since 2000, Λ hypernuclear spectroscopic experiments by the (e,e'k) reaction have been performed at the experimental hall C in Thomas Jefferson National Accelerator Facility (JLab Hall C). An experiment, JLab E05-115 was carried out to investigate Λ hypernuclei with a wide mass range (the mass number, A = 7, 9, 10, 12, 52). The latest analysis status of JLab E05-115 experiment is discussed in the present article.
Physics design of the injector source for ITER neutral beam injector (invited).
Antoni, V; Agostinetti, P; Aprile, D; Cavenago, M; Chitarin, G; Fonnesu, N; Marconato, N; Pilan, N; Sartori, E; Serianni, G; Veltri, P
2014-02-01
Two Neutral Beam Injectors (NBI) are foreseen to provide a substantial fraction of the heating power necessary to ignite thermonuclear fusion reactions in ITER. The development of the NBI system at unprecedented parameters (40 A of negative ion current accelerated up to 1 MV) requires the realization of a full scale prototype, to be tested and optimized at the Test Facility under construction in Padova (Italy). The beam source is the key component of the system and the design of the multi-grid accelerator is the goal of a multi-national collaborative effort. In particular, beam steering is a challenging aspect, being a tradeoff between requirements of the optics and real grids with finite thickness and thermo-mechanical constraints due to the cooling needs and the presence of permanent magnets. In the paper, a review of the accelerator physics and an overview of the whole R&D physics program aimed to the development of the injector source are presented.
Physics design of the injector source for ITER neutral beam injector (invited)
Antoni, V.; Agostinetti, P.; Aprile, D.; Chitarin, G.; Fonnesu, N.; Marconato, N.; Pilan, N.; Sartori, E.; Serianni, G. Veltri, P.; Cavenago, M.
2014-02-15
Two Neutral Beam Injectors (NBI) are foreseen to provide a substantial fraction of the heating power necessary to ignite thermonuclear fusion reactions in ITER. The development of the NBI system at unprecedented parameters (40 A of negative ion current accelerated up to 1 MV) requires the realization of a full scale prototype, to be tested and optimized at the Test Facility under construction in Padova (Italy). The beam source is the key component of the system and the design of the multi-grid accelerator is the goal of a multi-national collaborative effort. In particular, beam steering is a challenging aspect, being a tradeoff between requirements of the optics and real grids with finite thickness and thermo-mechanical constraints due to the cooling needs and the presence of permanent magnets. In the paper, a review of the accelerator physics and an overview of the whole R and D physics program aimed to the development of the injector source are presented.
Tang, Liguang; Chen, Chunhua; Gogami, Toshiyuki; Kawama, Daisuke; Han, Yuncheng; Yuan, Lulin; Matsumura, Akihiko; Okayasu, Yuichi; Seva, Tomislav; Rodriguez, Victor; Baturin, Pavlo; Acha Quimper, Armando; Achenbach, Carsten; Ahmidouch, Abdellah; Albayrak, Ibrahim; Androic, Darko; Asaturyan, Arshak; Asaturyan, Razmik; Ates, Ozgur; Badui, Rafael; Baker, Oliver; Benmokhtar, Fatiha; Boeglin, Werner; Bono, Jason; Bosted, Peter; Brash, Edward; Carter, Philip; Carlini, Roger; Chiba, Atsushi; Christy, Michael; Cole, Leon; Dalton, Mark; Danagoulian, Samuel; Daniel, Aji; De Leo, Raffaele; Dharmawardane, Kahanawita; Doi, Daisuke; Egiyan, Kim; Elaasar, Mostafa; Ent, Rolf; Fenker, Howard; Fujii, Yu; Furic, Miroslav; Gabrielyan, Marianna; Gan, Liping; Garibaldi, Franco; Gaskell, David; Gasparian, Ashot; Gibson, Edward; Gueye, Paul; Hashimoto, Osamu; Honda, D; Horn, Tanja; Hu, Bitao; Hungerford, Ed; Jayalath, Chandana; Jones, Mark; Johnston, Kathleen; Kalantarians, Narbe; Kanda, Hiroki; Kaneta, M; Kato, F; Kato, Seigo; Kawai, Masaharu; Keppel, Cynthia; Khanal, Hari; Kohl, M; Kramer, Laird; Lan, Kejian; Li, Ya; Habarakada Liyanage, Anusha; Luo, Wei; Mack, David; Maeda, Kazushige; Malace, Simona; Margaryan, Amur; Marikyan, Gagik; Markowitz, Pete; Maruta, Tomofumi; Maruyama, Nayuta; Maxwell, Victor; Millener, David; Miyoshi, Toshinobu; Mkrtchyan, Arthur; Mkrtchyan, Hamlet; Motoba, Toshio; Nagao, Sho; Nakamura, Satoshi; Narayan, Amrendra; Neville, Casey; Niculescu, Gabriel; Niculescu, Maria; Nunez, Angel; Nuruzzaman, nfn; Nomura, Hiroshi; Nonaka, Kenichi; Ohtani, Atsushi; Oyamada, Masamichi; Perez, Naipy; Petkovic, Tomislav; Pochodzalla, J; Qiu, Xiyu; Randeniya, Kapugodage; Raue, Brian; Reinhold, Joerg; Rivera, R; Roche, Julie; Samanta, Chhanda; Sato, Yoshinori; Sawatzky, Bradley; Segbefia, Edwin; Schott, Diane; Shichijo, Ayako; Simicevic, Neven; Smith, Gregory; Song, Yushou; Sumihama, Mizuki; Tadevosyan, Vardan; Takahashi, Toshiyuki; Taniya, Naotaka; Tsukada, Kyo; Tvaskis, Vladas; Veilleux, Micah; Vulcan, William; Wells, Steven; Wesselmann, Frank; Wood, Stephen; Yamamoto, Taku; Yan, Chen; Ye, Z; Yokota, Kosuke; Zhamkochyan, Simon; Zhu, Lingyan
2014-09-01
Since the pioneering experiment, E89-009 studying hypernuclear spectroscopy using the $(e,e^{\\prime}K^+)$ reaction was completed, two additional experiments, E01-011 and E05-115, were performed at Jefferson Lab. These later experiments used a modified experimental design, the "Tilt Method", to dramatically suppress the large electromagnetic background, and allowed for a substantial increase in luminosity. Additionally, a new kaon spectrometer, HKS (E01-011), a new electron spectrometer, HES, and a new splitting magnet were added to produce precision, high-resolution hypernuclear spectroscopy. These two experiments, E01-011 and E05-115, resulted in two new data sets, producing sub-MeV energy resolution in the spectra of ${}^{7}_{\\Lambda}\\text{He}$, ${}^{12}_{\\Lambda}\\text{B}$ and ${}^{28}_{\\Lambda} \\text{Al}$ and ${}^{7}_{\\Lambda}\\text{He}$, ${}^{10}_{\\Lambda}\\text{Be}$, ${}^{12}_{\\Lambda}\\text{B}$ and ${}^{52}_{\\Lambda}\\text{V}$. All three experiments obtained a ${}^{12}_{\\Lambda}\\text{B}$, spectrum, which is the most characteristic $p$-shell hypernucleus and is commonly used for calibration. Independent analyses of these different experiments demonstrate excellent consistency and provide the clearest level structure to date of this hypernucleus as produced by the $(e,e^{\\prime}K^+)$ reaction. This paper presents details of these experiments, and the extraction and analysis of the observed ${}^{12}_{\\Lambda}\\text{B}$ spectrum.
Testing Short Samples of ITER Conductors and Projection of Their Performance in ITER Magnets
Martovetsky, N N
2007-08-20
Qualification of the ITER conductor is absolutely necessary. Testing large scale conductors is expensive and time consuming. To test straight 3-4m long samples in a bore of a split solenoid is a relatively economical way in comparison with fabrication of a coil to be tested in a bore of a background field solenoid. However, testing short sample may give ambiguous results due to different constraints in current redistribution in the cable or other end effects which are not present in the large magnet. This paper discusses processes taking place in the ITER conductor, conditions when conductor performance could be distorted and possible signal processing to deduce behavior of ITER conductors in ITER magnets from the test data.
Monte Carlo simulation of ICRF discharge initiation in ITER
NASA Astrophysics Data System (ADS)
Tripský, M.; Wauters, T.; Lyssoivan, A.; Křivská, A.; Louche, F.; Van Schoor, M.; Noterdaeme, J.-M.
2015-12-01
Discharges produced and sustained by ion cyclotron range of frequency (ICRF) waves in absence of plasma current will be used on ITER for (ion cyclotron-) wall conditioning (ICWC). The here presented simulations aim at ensuring that the ITER ICRH&CD system can be safely employed for ICWC and at finding optimal parameters to initiate the plasma. The 1D Monte Carlo code RFdinity1D3V was developed to simulate ICRF discharge initiation. The code traces the electron motion along one toroidal magnetic field line, accelerated by the RF field in front of the ICRF antenna. Electron collisions in the calculations are handled by a Monte Carlo procedure taking into account their energies and the related electron collision cross sections for collisions with H2, H2+ and H+. The code also includes Coulomb collisions between electrons and ions (e - e, e - H2+ , e - H+). We study the electron multiplication rate as a function of the RF discharge parameters (i) antenna input power (0.1-5MW), and (ii) the neutral pressure (H2) for two antenna phasing (monopole [0000]-phasing and small dipole [0π0π]-phasing). Furthermore, we investigate the electron multiplication rate dependency on the distance from the antenna straps. This radial dependency results from the decreasing electric amplitude and field smoothening with increasing distance from the antenna straps. The numerical plasma breakdown definition used in the code corresponds to the moment when a critical electron density nec for the low hybrid resonance (ω = ωLHR) is reached. This numerical definition was previously found in qualitative agreement with experimental breakdown times obtained from the literature and from experiments on the ASDEX Upgrade and TEXTOR.
Cosmic acceleration and the helicity-0 graviton
Rham, Claudia de; Heisenberg, Lavinia; Gabadadze, Gregory; Pirtskhalava, David
2011-05-15
We explore cosmology in the decoupling limit of a nonlinear covariant extension of Fierz-Pauli massive gravity obtained recently in arXiv:1007.0443. In this limit the theory is a scalar-tensor model of a unique form defined by symmetries. We find that it admits a self-accelerated solution, with the Hubble parameter set by the graviton mass. The negative pressure causing the acceleration is due to a condensate of the helicity-0 component of the massive graviton, and the background evolution, in the approximation used, is indistinguishable from the {Lambda}CDM model. Fluctuations about the self-accelerated background are stable for a certain range of parameters involved. Most surprisingly, the fluctuation of the helicity-0 field above its background decouples from an arbitrary source in the linearized theory. We also show how massive gravity can remarkably screen an arbitrarily large cosmological constant in the decoupling limit, while evading issues with ghosts. The obtained static solution is stable against small perturbations, suggesting that the degravitation of the vacuum energy is possible in the full theory. Interestingly, however, this mechanism postpones the Vainshtein effect to shorter distance scales. Hence, fifth force measurements severely constrain the value of the cosmological constant that can be neutralized, making this scheme phenomenologically not viable for solving the old cosmological constant problem. We briefly speculate on a possible way out of this issue.
Reducing the latency of the Fractal Iterative Method to half an iteration
NASA Astrophysics Data System (ADS)
Béchet, Clémentine; Tallon, Michel
2013-12-01
The fractal iterative method for atmospheric tomography (FRiM-3D) has been introduced to solve the wavefront reconstruction at the dimensions of an ELT with a low-computational cost. Previous studies reported the requirement of only 3 iterations of the algorithm in order to provide the best adaptive optics (AO) performance. Nevertheless, any iterative method in adaptive optics suffer from the intrinsic latency induced by the fact that one iteration can start only once the previous one is completed. Iterations hardly match the low-latency requirement of the AO real-time computer. We present here a new approach to avoid iterations in the computation of the commands with FRiM-3D, thus allowing low-latency AO response even at the scale of the European ELT (E-ELT). The method highlights the importance of "warm-start" strategy in adaptive optics. To our knowledge, this particular way to use the "warm-start" has not been reported before. Futhermore, removing the requirement of iterating to compute the commands, the computational cost of the reconstruction with FRiM-3D can be simplified and at least reduced to half the computational cost of a classical iteration. Thanks to simulations of both single-conjugate and multi-conjugate AO for the E-ELT,with FRiM-3D on Octopus ESO simulator, we demonstrate the benefit of this approach. We finally enhance the robustness of this new implementation with respect to increasing measurement noise, wind speed and even modeling errors.
Quartz Microbalance Study of 400-angstrom Thick Films near the lambda Point
NASA Technical Reports Server (NTRS)
Chan, Moses H. W.
2003-01-01
In a recent measurement we observed the thinning of an adsorbed helium film induced by the confinement of critical fluctuations a few millikelvin below the lambda point. A capacitor set-up was used to measure this Casimir effect. In this poster we will present our measurement of an adsorbed helium film of 400 angstroms near the lambda point with a quartz microbalance. For films this thick, we must take into account the non-linear dynamics of the shear waves in the fluid. In spite of the added complications, we were able to confirm the thinning of the film due to the Casimir effect and the onset of the superfluid transition. In addition, we observe a sharp anomaly at the bulk lambda point, most likely related to critical dissipation of the first sound. This work is carried out in collaboration with Rafael Garcia, Stephen Jordon and John Lazzaretti. This work is funded by NASA's Office of Biological and Physical Research under grant.
B^0_s and lambda^0_b lifetimes and branching ratios at the Tevatron
Behari, S.; /Johns Hopkins U.
2006-12-01
The authors review B{sub s}{sup 0} and {Lambda}{sub b}{sup 0} lifetime and branching ratio measurements from the CDF and D0 experiments at the Tevatron Run II. Using up to 1 fb{sup -1} data samples per experiment, {Lambda}{sub b}{sup 0} lifetime in J/{Psi}{Lambda}{sup 0} decays, B{sub s}{sup 0} lifetime difference in K{sup +}K{sup -} and D{sub s}{sup (*)+} D{sub s}{sup (*)-} decays and B{sub s}{sup 0} branching ratio in D{sub s1}{sup -}(2536){mu}{sup +} {nu}X decays are reported.
{lambda}{sub c} Enhancement from Strongly Coupled Quark-Gluon Plasma
Lee, Su Houng; Ohnishi, Kazuaki; Yasui, Shigehiro; Yoo, In-Kwon; Ko, Che Ming
2008-06-06
We propose the enhancement of {lambda}{sub c} as a novel quark-gluon plasma signal in heavy ion collisions at the BNL Relativistic Heavy Ion Collider and the CERN Large Hadron Collider. Assuming a stable bound diquark state in the strongly coupled quark-gluon plasma near the critical temperature, we argue that the direct two-body collision between a c quark and a [ud] diquark would lead to an enhanced {lambda}{sub c} production in comparison with the normal three-body collision among independent c, u, and d quarks. In the coalescence model, we find that the {lambda}{sub c}/D yield ratio is enhanced substantially due to the diquark correlation.
Asymmetric lambda/4-shifted InGaAsP/InP DFB lasers
Usami, M.; Akiba, S.; Utaka, K.
1987-06-01
1.5 ..mu..m asymmetric lambda/4-shifted InGaAsP/InP DFB lasers, in which the lambda/4-shift position was moved from the center of the DFB region toward the front side, were made in order to obtain higher output power with high single-longitudinal-mode (SLM) yield. Statistical measurements revealed that it was effective for the increase of the differential quantum efficiency from the front facet without a remarkable decrease of the SLM yield to move the lambda/4-shift position to the front facet by 10-15 percent of the total DFB length. The output efficiencies of the diodes with AR coatings on the window structure were almost coincident to those expected from theoretical calculations.
Observation of the Helium 7 {Lambda} hypernucleus by the (e,e'K+) reaction
Nakamura, Satoshi; Okayasu, Yuichi; Seva, Tomislav; Rodriguez, Victor; Baturin, Pavlo; Yuan, Lulin; Acha Quimper, Armando; Ahmidouch, Abdellah; Androic, Darko; Asaturyan, Arshak; Asaturyan, Razmik; Baker, Oliver; Benmokhtar, Fatiha; Boeglin, Wener; Bosted, Peter; Carlini, Roger; Chen, Chunhua; Christy, Michael; Cole, Leon; Danagoulian, Samuel; Daniel, Aji; Dharmawardane, Kahanawita; Egiyan, Kim; Elaasar, Mostafa; Ent, Rolf; Fenker, Howard; Fujii, Yu; Furic, Miroslav; Gan, Liping; Gaskell, David; Gasparian, Ashot; Gibson, Edward; Toshiyuki, Gogami; Gueye, Paul; Han, Yuncheng; Hashimoto, Osamu; Hiyama, E; Honda, D; Horn, Tanja; Hu, Bitao; Hungerford, Ed; Jayalath, Chandana; Jones, Mark; Johnston, Kathleen; Kalantarians, Narbe; Kanda, Hiroki; Kaneta, M; Kato, Seigo; Kato, Shigeki; Kawama, Daisuke; Keppel, Cynthia; Kramer, Laird; Lan, Kejian; Luo, Wei; Mack, David; Maeda, Kazushige; Malace, Simona; Margaryan, Amur; Marikyan, Gagik; Markowitz, Pete; Maruta, Tomofumi; Maruyama, Nayuta; Miyoshi, Toshinuobu; Mkrtchyan, Arthur; Mkrtchyan, Hamlet; Nagao, Sho; Navasardyan, Tigran; Niculescu, Gabriel; Niculescu, Maria-Ioana; Nonaka, Kenichi; Ohtani, Atsushi; Oyamada, Masamichi; Perez, Naipy; Petkovic, Tomislav; Randeniya, Kapugodage; Raue, Brian; Reinhold, Joerg; Rivera Castillo, Roberto; Roche, Julie; Sato, Yoshinori; Segbefia, Edwin; Simicevic, Neven; Smith, Gregory; Song, Yushou; Sumihama, Mizuki; Tadevosyan, Vardan; Takahashi, Toshiyuki; Tang, Liguang; Tsukada, Kyo; Tvaskis, Vladas; Vulcan, William; Wells, Steven; Wood, Stephen; Yan, Chen; Zhamkochyan, Simon
2013-01-01
An experiment with a newly developed high-resolution kaon spectrometer (HKS) and a scattered electron spectrometer with a novel configuration was performed in Hall C at Jefferson Lab (JLab). The ground state of a neutron-rich hypernucleus, He 7 {Lambda}, was observed for the first time with the (e,e'K+) reaction with an energy resolution of ~0.6 MeV. This resolution is the best reported to date for hypernuclear reaction spectroscopy. The He 7 {Lambda} binding energy supplies the last missing information of the A=7, T=1 hypernuclear iso-triplet, providing a new input for the charge symmetry breaking (CSB) effect of {Lambda} N potential.
Correlated Leading Baryon-antibaryon Production in e+e- to ccbar to Lambda_c+ antiLambda_c- X
Aubert, B.; Karyotakis, Y.; Lees, J.P.; Poireau, V.; Prencipe, E.; Prudent, X.; Tisserand, V.; Garra Tico, J.; Grauges, E.; Martinelli, M.; Palano, A.; Pappagallo, M.; Eigen, G.; Stugu, B.; Sun, L.; Battaglia, M.; Brown, D.N.; Hooberman, B.; Kerth, L.T.; Kolomensky, Yu.G.; Lynch, G. /UC, Berkeley /Birmingham U. /Ruhr U., Bochum /British Columbia U. /Brunel U. /Novosibirsk, IYF /UC, Irvine /UCLA /UC, Riverside /UC, San Diego /UC, Santa Barbara /UC, Santa Cruz /Caltech /Cincinnati U. /Colorado U. /Colorado State U. /Dortmund U. /Dresden, Tech. U. /Ecole Polytechnique /Edinburgh U. /INFN, Ferrara /Ferrara U. /INFN, Ferrara /INFN, Ferrara /Ferrara U. /INFN, Ferrara /INFN, Ferrara /Ferrara U. /Frascati /INFN, Genoa /Genoa U. /INFN, Genoa /INFN, Genoa /Genoa U. /INFN, Genoa /INFN, Genoa /Genoa U. /Harvard U. /Heidelberg U. /Humboldt U., Berlin /Imperial Coll., London /Iowa State U. /Iowa State U. /Johns Hopkins U. /Orsay, LAL /LLNL, Livermore /Liverpool U. /Queen Mary, U. of London /Royal Holloway, U. of London /Louisville U. /Mainz U., Inst. Kernphys. /Manchester U. /Maryland U. /Massachusetts U., Amherst /MIT /McGill U. /INFN, Milan /Milan U. /INFN, Milan /INFN, Milan /Milan U. /Mississippi U. /Montreal U. /Mt. Holyoke Coll. /INFN, Naples /Naples U. /INFN, Naples /INFN, Naples /Naples U. /NIKHEF, Amsterdam /Notre Dame U. /Ohio State U. /Oregon U. /INFN, Padua /Padua U. /INFN, Padua /INFN, Padua /Padua U. /Paris U., VI-VII /Pennsylvania U. /INFN, Perugia /Perugia U. /INFN, Pisa /Pisa U. /INFN, Pisa /Pisa, Scuola Normale Superiore /INFN, Pisa /Pisa U. /INFN, Pisa /Princeton U. /INFN, Rome /INFN, Rome /Rome U. /INFN, Rome /INFN, Rome /Rome U. /INFN, Rome /INFN, Rome /Rome U. /INFN, Rome /INFN, Rome /Rome U. /INFN, Rome /Rostock U. /Rutherford /DAPNIA, Saclay /SLAC /South Carolina U. /Stanford U., Phys. Dept. /SUNY, Albany /Tel Aviv U. /Tennessee U. /Texas U. /Texas U., Dallas /INFN, Turin /Turin U. /INFN, Trieste /Trieste U. /Valencia U. /Victoria U. /Warwick U. /Wisconsin U., Madison
2011-08-22
We present a study of 649 {+-} 35 e{sup +}e{sup -} {yields} c{bar c} events produced at {radical}s {approx} 10.6 GeV containing both a {Lambda}{sub c}{sup +} baryon and a {bar {Lambda}}{sub c}{sup -} antibaryon. The number observed is roughly four times that expected if the leading charmed hadron types are uncorrelated, confirming an observation by the CLEO Collaboration. We find a 2-jet topology in these events but very few additional baryons, demonstrating that the primary c and {bar c} are predominantly contained in a correlated baryon-antibaryon system. In addition to the charmed baryons we observe on average 2.6 {+-} 0.2 charged intermediate mesons, predominantly pions, carrying 65% of the remaining energy.
Adler, C; Ahammed, Z; Allgower, C; Amonett, J; Anderson, B D; Anderson, M; Averichev, G S; Balewski, J; Barannikova, O; Barnby, L S; Baudot, J; Bekele, S; Belaga, V V; Bellwied, R; Berger, J; Bichsel, H; Billmeier, A; Bland, L C; Blyth, C O; Bonner, B E; Boucham, A; Brandin, A; Bravar, A; Cadman, R V; Caines, H; Calderón de la Barca Sánchez, M; Cardenas, A; Carroll, J; Castillo, J; Castro, M; Cebra, D; Chaloupka, P; Chattopadhyay, S; Chen, Y; Chernenko, S P; Cherney, M; Chikanian, A; Choi, B; Christie, W; Coffin, J P; Cormier, T M; Cramer, J G; Crawford, H J; Deng, W S; Derevschikov, A A; Didenko, L; Dietel, T; Draper, J E; Dunin, V B; Dunlop, J C; Eckardt, V; Efimov, L G; Emelianov, V; Engelage, J; Eppley, G; Erazmus, B; Fachini, P; Faine, V; Filimonov, K; Finch, E; Fisyak, Y; Flierl, D; Foley, K J; Fu, J; Gagliardi, C A; Gagunashvili, N; Gans, J; Gaudichet, L; Germain, M; Geurts, F; Ghazikhanian, V; Grachov, O; Grigoriev, V; Guedon, M; Gushin, E; Hallman, T J; Hardtke, D; Harris, J W; Henry, T W; Heppelmann, S; Herston, T; Hippolyte, B; Hirsch, A; Hjort, E; Hoffmann, G W; Horsley, M; Huang, H Z; Humanic, T J; Igo, G; Ishihara, A; Ivanshin, Yu I; Jacobs, P; Jacobs, W W; Janik, M; Johnson, I; Jones, P G; Judd, E G; Kaneta, M; Kaplan, M; Keane, D; Kiryluk, J; Kisiel, A; Klay, J; Klein, S R; Klyachko, A; Konstantinov, A S; Kopytine, M; Kotchenda, L; Kovalenko, A D; Kramer, M; Kravtsov, P; Krueger, K; Kuhn, C; Kulikov, A I; Kunde, G J; Kunz, C L; Kutuev, R Kh; Kuznetsov, A A; Lakehal-Ayat, L; Lamont, M A C; Landgraf, J M; Lange, S; Lansdell, C P; Lasiuk, B; Laue, F; Lebedev, A; Lednický, R; Leontiev, V M; LeVine, M J; Li, Q; Lindenbaum, S J; Lisa, M A; Liu, F; Liu, L; Liu, Z; Liu, Q J; Ljubicic, T; Llope, W J; LoCurto, G; Long, H; Longacre, R S; Lopez-Noriega, M; Love, W A; Ludlam, T; Lynn, D; Ma, J; Majka, R; Margetis, S; Markert, C; Martin, L; Marx, J; Matis, H S; Matulenko, Yu A; McShane, T S; Meissner, F; Melnick, Yu; Meschanin, A; Messer, M; Miller, M L; Milosevich, Z; Minaev, N G; Mitchell, J; Moiseenko, V A; Moore, C F; Morozov, V; de Moura, M M; Munhoz, M G; Nelson, J M; Nevski, P; Nikitin, V A; Nogach, L V; Norman, B; Nurushev, S B; Odyniec, G; Ogawa, A; Okorokov, V; Oldenburg, M; Olson, D; Paic, G; Pandey, S U; Panebratsev, Y; Panitkin, S Y; Pavlinov, A I; Pawlak, T; Perevoztchikov, V; Peryt, W; Petrov, V A; Planinic, M; Pluta, J; Porile, N; Porter, J; Poskanzer, A M; Potrebenikova, E; Prindle, D; Pruneau, C; Putschke, J; Rai, G; Rakness, G; Ravel, O; Ray, R L; Razin, S V; Reichhold, D; Reid, J G; Retiere, F; Ridiger, A; Ritter, H G; Roberts, J B; Rogachevski, O V; Romero, J L; Rose, A; Roy, C; Rykov, V; Sakrejda, I; Salur, S; Sandweiss, J; Saulys, A C; Savin, I; Schambach, J; Scharenberg, R P; Schmitz, N; Schroeder, L S; Schüttauf, A; Schweda, K; Seger, J; Seliverstov, D; Seyboth, P; Shahaliev, E; Shestermanov, K E; Shimanskii, S S; Shvetcov, V S; Skoro, G; Smirnov, N; Snellings, R; Sorensen, P; Sowinski, J; Spinka, H M; Srivastava, B; Stephenson, E J; Stock, R; Stolpovsky, A; Strikhanov, M; Stringfellow, B; Struck, C; Suaide, A A P; Sugarbaker, E; Suire, C; Sumbera, M; Surrow, B; Symons, T J M; Szanto de Toledo, A; Szarwas, P; Tai, A; Takahashi, J; Tang, A H; Thomas, J H; Thompson, M; Tikhomirov, V; Tokarev, M; Tonjes, M B; Trainor, T A; Trentalange, S; Tribble, R E; Trofimov, V; Tsai, O; Ullrich, T; Underwood, D G; Van Buren, G; VanderMolen, A M; Vasilevski, I M; Vasiliev, A N; Vigdor, S E; Voloshin, S A; Wang, F; Ward, H; Watson, J W; Wells, R; Westfall, G D; Whitten, C; Wieman, H; Willson, R; Wissink, S W; Witt, R; Wood, J; Xu, N; Xu, Z; Yakutin, A E; Yamamoto, E; Yang, J; Yepes, P; Yurevich, V I; Zanevski, Y V; Zborovský, I; Zhang, H; Zhang, W M; Zoulkarneev, R; Zubarev, A N
2002-09-23
We report STAR results on the azimuthal anisotropy parameter v(2) for strange particles K(0)(S), Lambda, and Lambda at midrapidity in Au+Au collisions at sqrt[s(NN)]=130 GeV at the Relativistic Heavy Ion Collider. The value of v(2) as a function of transverse momentum, p(t), of the produced particle and collision centrality is presented for both particles up to p(t) approximately 3.0 GeV/c. A strong p(t) dependence in v(2) is observed up to 2.0 GeV/c. The v(2) measurement is compared with hydrodynamic model calculations. The physics implications of the p(t) integrated v(2) magnitude as a function of particle mass are also discussed. PMID:12225018
Overview on Experiments On ITER-like Antenna On JET And ICRF Antenna Design For ITER
Nightingale, M. P. S.; Blackman, T.; Edwards, D.; Fanthome, J.; Graham, M.; Hamlyn-Harris, C.; Hancock, D.; Jacquet, P.; Mayoral, M.-L.; Monakhov, I.; Nicholls, K.; Stork, D.; Whitehurst, A.; Wilson, D.; Wooldridge, E.
2009-11-26
Following an overview of the ITER Ion Cyclotron Resonance Frequency (ICRF) system, the JET ITER-like antenna (ILA) will be described. The ILA was designed to test the following ITER issues: (a) reliable operation at power densities of order 8 MW/m{sup 2} at voltages up to 45 kV using a close-packed array of straps; (b) powering through ELMs using an internal (in-vacuum) conjugate-T junction; (c) protection from arcing in a conjugate-T configuration, using both existing and novel systems; and (d) resilience to disruption forces. ITER-relevant results have been achieved: operation at high coupled power density; control of the antenna matching elements in the presence of high inter-strap coupling, use of four conjugate-T systems (as would be used in ITER, should a conjugate-T approach be used); operation with RF voltages on the antenna structures up to 42 kV; achievement of ELM tolerance with a conjugate-T configuration by operating at 3{omega} real impedance at the conjugate-T point; and validation of arc detection systems on conjugate-T configurations in ELMy H-mode plasmas. The impact of these results on the predicted performance and design of the ITER antenna will be reviewed. In particular, the implications of the RF coupling measured on JET will be discussed.
George, Thomas; Beevi, S Naseema; Xavier, George; Kumar, N Pratheesh; George, Jayesh
2013-06-01
The dissipation kinetics and method for estimation of residues of chlorpyrifos and lambda-cyhalothrin in cardamom were studied and developed. The limit of detection and limit of quantitation arrived for the compounds were 0.01 and 0.025 μg g(-1), respectively. Gas chromatographic response of chlorpyrifos and lambda-cyhalothrin residues was linear in the range of 0.01-0.50 μg g(-1) and the mean recovery obtained was 97.3 % for chlorpyrifos and 98.9 % for lambda-cyhalothrin with satisfactory relative standard deviation values. The mean initial residues of chlorpyrifos applied at a concentration of 0.05 % in cardamom was 2.5 μg g(-1) and the residue was 8.1 μg g(-1) after processing, with a processing factor of 3.24, while lambda-cyhalothrin when applied at 0.0025 % resulted in initial residues of 1.63 μg g(-1) that magnified to 4.86 μg g(-1) on curing, with a processing factor of 2.98. The half-life of chlorpyrifos was in the range of 5.1-5.24 days while that of lambda-cyhalothrin was in the range of 4.40-4.55 days. The processing factor arrived at in the above experiment lead to the conclusion that the residues of chlorpyrifos got magnified to 3.24-3.68 times and that of lambda-cyhalothrin got magnified to 2.98-3.46 times of initial residues, consequent to loss of weight due to dehydration during curing. PMID:23079795
George, Thomas; Beevi, S Naseema; Xavier, George; Kumar, N Pratheesh; George, Jayesh
2013-06-01
The dissipation kinetics and method for estimation of residues of chlorpyrifos and lambda-cyhalothrin in cardamom were studied and developed. The limit of detection and limit of quantitation arrived for the compounds were 0.01 and 0.025 μg g(-1), respectively. Gas chromatographic response of chlorpyrifos and lambda-cyhalothrin residues was linear in the range of 0.01-0.50 μg g(-1) and the mean recovery obtained was 97.3 % for chlorpyrifos and 98.9 % for lambda-cyhalothrin with satisfactory relative standard deviation values. The mean initial residues of chlorpyrifos applied at a concentration of 0.05 % in cardamom was 2.5 μg g(-1) and the residue was 8.1 μg g(-1) after processing, with a processing factor of 3.24, while lambda-cyhalothrin when applied at 0.0025 % resulted in initial residues of 1.63 μg g(-1) that magnified to 4.86 μg g(-1) on curing, with a processing factor of 2.98. The half-life of chlorpyrifos was in the range of 5.1-5.24 days while that of lambda-cyhalothrin was in the range of 4.40-4.55 days. The processing factor arrived at in the above experiment lead to the conclusion that the residues of chlorpyrifos got magnified to 3.24-3.68 times and that of lambda-cyhalothrin got magnified to 2.98-3.46 times of initial residues, consequent to loss of weight due to dehydration during curing.
Fattebert, J
2008-07-29
We describe an iterative algorithm to solve electronic structure problems in Density Functional Theory. The approach is presented as a Subspace Accelerated Inexact Newton (SAIN) solver for the non-linear Kohn-Sham equations. It is related to a class of iterative algorithms known as RMM-DIIS in the electronic structure community. The method is illustrated with examples of real applications using a finite difference discretization and multigrid preconditioning.
Iterative performance of various formulations of the SPN equations
NASA Astrophysics Data System (ADS)
Zhang, Yunhuang; Ragusa, Jean C.; Morel, Jim E.
2013-11-01
In this paper, the Standard, Composite, and Canonical forms of the Simplified PN (SPN) equations are reviewed and their corresponding iterative properties are compared. The Gauss-Seidel (FLIP), Explicit, and preconditioned Source Iteration iterative schemes have been analyzed for both isotropic and highly anisotropic (Fokker-Planck) scattering. The iterative performance of the various SPN forms is assessed using Fourier analysis, corroborated with numerical experiments.
The lambda point experiment in microgravity. [He heat capacity close to phase transition point
NASA Technical Reports Server (NTRS)
Lipa, J. A.; Chui, T. C. P.; Marek, D.
1987-01-01
An experiment for performing high-resolution measurements of the heat capacity singularity at the lambda point of helium in microgravity conditions is described. By obtaining such measurements in space, it is expected that the intrinsic distortion of the transition would be reduced by at least two orders of magnitude, allowing the theory of cooperative phase transitions to be more effectively tested. Technology developments for the lambda point experiment include a new high-resolution thermometer, an advanced thermal control system, and a reusable flight-qualified superfluid helium dewar.
Near threshold {Lambda} and {Sigma}{sup 0} production in pp collisions
Gasparian, A.; Haidenbauer, J.; Hanhart, C.; Kondratyuk, L.; Speth, J.
2000-12-31
The reactions pp {yields} p{Lambda}K{sup +} and pp {yields} p{Sigma}{sup 0}K{sup +} are studied near their thresholds. The strangeness production process is described by the {pi}- and K exchange mechanisms. Effects from the final-state interaction in the hyperon-nucleon system are taken into account rigorously. It is shown that the experimentally observed strong suppression of {Sigma}{sup 0} production compared to {Lambda} production can be explained by a destructive interference between {pi} and K exchange in the reaction pp {yields} p{Sigma}{sup 0}K{sup +}.
Branching ratios from B{sub s} and {Lambda}{sub b}{sup 0}
Matthew S. Martin
2004-05-28
CDF Run II relative branching ratio measurements for 65 pb{sup -1} of data in the channels B{sub s} {yields} D{sub s}{sup {-+}}{pi}{sup {-+}}, {Lambda} {sub b}{sup 0} {yields} {Lambda}{sub c}{sup {+-}}{pi}{sup {-+}} and B {yields} h{sup +}h{sup -} are presented. Further, an observation of B{sub s} {yields} K{sup {+-}} K{sup {-+}} and a measurement of A{sub CP} are presented.
Structure of Lambda(1405) and threshold behavior of pi Sigma scattering
Yoichi Ikeda, Tesuo Hyodo, Daisuke Jido, Hiroyuki Kamano, Toru Sato, Koichi Yazaki
2011-01-01
The scattering length and effective range of the pi-Sigma channel are studied in order to characterize the strangeness S = -1 meson-baryon scattering and the Lambda (1405) resonance. We examine various off-shell dependence of the amplitude in dynamical chiral models to evaluate the threshold quantities with the constraint at the KN threshold. We find that the pi-Sigma threshold parameters are important to the structure of the Lambda (1405) resonance and provide further constraints on the subthreshold extrapolation of the KN interaction.
Integration of bacteriophage. lambda. into the cryptic lambdoid prophages of Escherichia coli
Lichens-Park, A. ); Smith, C.L. ); Syvanen, M. )
1990-05-01
Bacteriophage lambda missing its chromosomal attachment site will integrate into recA{sup +} Escherichia coli K-12 and C at the site of cryptic prophages. The specific regions in which these recombination events occur were identified in both lambda and the bacterial chromosomes. A NotI restriction site on the prophage allowed its physical mapping. This allowed them to identify the locations of Rac, Qin, and Qsr{prime} cryptic prophages on the NotI map of E. coli K-12 and, by analogy, to identify the cryptic prophage in E. coli C as Qin. No new cryptic prophages were detected in E. coli K-12.
Formation of Primordial Stars in a Lambda-CDM Universe
Yoshida, Naoki; Omukai, Kazuyuki; Hernquist, Lars; Abel, Tom; /KIPAC, Menlo Park
2006-06-09
Primordial stars are formed from a chemically pristine gas consisting of hydrogen and helium. They are believed to have been born at some early epoch in the history of the Universe and to have enriched the interstellar medium with synthesized heavy elements before the emergence of ordinary stellar populations. We study the formation of the first generation of stars in the standard cold dark matter model. We follow the gravitational collapse and thermal evolution of primordial gas clouds within early cosmic structures using very high-resolution, cosmological hydrodynamic simulations. Our simulation achieves a dynamic range of {approx} 10{sup 10} in length scale. With accurate treatment of atomic and molecular physics, it allows us to study the chemo-thermal evolution of primordial gas clouds to densities up to {rho} {approx} 2 x 10{sup -8}g cm{sup -3} (n{sub H} {approx} 10{sup 16}cm{sup -3}) without assuming any a priori equation of state; a six orders of magnitudes improvement over previous three-dimensional calculations. We implement an extensive chemistry network for hydrogen, helium and deuterium. All the relevant atomic and molecular cooling and heating processes, including cooling by collision-induced continuum emission, are implemented. For calculating optically thick H{sub 2} cooling at high densities, we use the Sobolev method (Sobolev 1960) and evaluate the molecular line opacities for a few hundred lines. We validate the accuracy of the method by performing a spherical collapse test and comparing the results with those of accurate one-dimensional calculations that treat the line radiative transfer problem in a fully self-consistent manner. We then perform a cosmological simulation adopting the standard {Lambda}CDM model. Dense gas clumps are formed at the centers of low mass ({approx} 10{sup 5-6}M{sub {circle_dot}}) dark matter halos at redshifts z {approx} 20, and they collapse gravitationally when the cloud mass exceeds a few hundred solar masses. To
Tajima, Toshiki
2006-04-18
A system and method of accelerating ions in an accelerator to optimize the energy produced by a light source. Several parameters may be controlled in constructing a target used in the accelerator system to adjust performance of the accelerator system. These parameters include the material, thickness, geometry and surface of the target.
Confined alpha particle diagnostic system using an energetic He{sup 0} beam for ITER
Sasao, M.; Shinto, K.; Isobe, M.; Nishiura, M.; Kaneko, O.; Wada, M.; Walker, C. I.; Kitajima, S.; Okamoto, A.; Sugawara, H.; Takeuchi, S.; Tanaka, N.; Aoyama, H.; Kisaki, M.
2006-10-15
The beam neutralization system for measurement of the spatial and velocity distributions of alpha particles of ITER plasmas was studied. As forward angle detection against the beam injection direction is required for effective neutralization, arrangement of the measurement system using possible ports in ITER configuration is proposed. The count rate of neutralized alpha particles produced by the double charge exchange interaction with energetic He{sup 0} beam particles injected is estimated. The ratios of signal to neutron-induced noise are evaluated. When a He{sup 0} beam produced by autodetachment from a 1-1.5 MeV He{sup -} beam of 10 mA is injected, the signal to noise ratio becomes greater than 1 at {rho}<0.4, even without beam modulation. Usage of a lock-in technique at the frequency of radio-frequency quadrapole accelerator will make measurement at the outer region possible.
Communication: Iteration-free, weighted histogram analysis method in terms of intensive variables
Kim, Jaegil; Keyes, Thomas; Straub, John E.
2011-01-01
We present an iteration-free weighted histogram method in terms of intensive variables that directly determines the inverse statistical temperature, βS = ∂S/∂E, with S the microcanonical entropy. The method eliminates iterative evaluations of the partition functions intrinsic to the conventional approach and leads to a dramatic acceleration of the posterior analysis of combining statistically independent simulations with no loss in accuracy. The synergistic combination of the method with generalized ensemble weights provides insights into the nature of the underlying phase transitions via signatures in βS characteristic of finite size systems. The versatility and accuracy of the method is illustrated for the Ising and Potts models. PMID:21842919
Overview of the negative ion based neutral beam injectors for ITER
NASA Astrophysics Data System (ADS)
Schunke, B.; Boilson, D.; Chareyre, J.; Choi, C.-H.; Decamps, H.; El-Ouazzani, A.; Geli, F.; Graceffa, J.; Hemsworth, R.; Kushwah, M.; Roux, K.; Shah, D.; Singh, M.; Svensson, L.; Urbani, M.
2016-02-01
The ITER baseline foresees 2 Heating Neutral Beams (HNB's) based on 1 MeV 40 A D- negative ion accelerators, each capable of delivering 16.7 MW of deuterium atoms to the DT plasma, with an optional 3rd HNB injector foreseen as a possible upgrade. In addition, a dedicated diagnostic neutral beam will be injecting ≈22 A of H0 at 100 keV as the probe beam for charge exchange recombination spectroscopy. The integration of the injectors into the ITER plant is nearly finished necessitating only refinements. A large number of components have passed the final design stage, manufacturing has started, and the essential test beds—for the prototype route chosen—will soon be ready to start.
Overview of the negative ion based neutral beam injectors for ITER.
Schunke, B; Boilson, D; Chareyre, J; Choi, C-H; Decamps, H; El-Ouazzani, A; Geli, F; Graceffa, J; Hemsworth, R; Kushwah, M; Roux, K; Shah, D; Singh, M; Svensson, L; Urbani, M
2016-02-01
The ITER baseline foresees 2 Heating Neutral Beams (HNB's) based on 1 MeV 40 A D(-) negative ion accelerators, each capable of delivering 16.7 MW of deuterium atoms to the DT plasma, with an optional 3rd HNB injector foreseen as a possible upgrade. In addition, a dedicated diagnostic neutral beam will be injecting ≈22 A of H(0) at 100 keV as the probe beam for charge exchange recombination spectroscopy. The integration of the injectors into the ITER plant is nearly finished necessitating only refinements. A large number of components have passed the final design stage, manufacturing has started, and the essential test beds-for the prototype route chosen-will soon be ready to start.
High power plasma interaction with tungsten grades in ITER relevant conditions
NASA Astrophysics Data System (ADS)
Garkusha, I. E.; Makhlaj, V. A.; Aksenov, N. N.; Byrka, O. V.; Malykhin, S. V.; Pugachov, A. T.; Bazylev, B.; Landman, I.; Pinsuk, G.; Linke, J.; Wirtz, M.; Sadowski, M. J.; Skladnik-Sadowska, E.
2015-03-01
Experimental simulations of ITER-like transient events with relevant surface heat load parameters (energy density up to 1.1 MJ/m2 and the pulse duration of 0.25 ms) as well as particle loads (varied in wide range from 1023 to 1027 ion/m2 s) were carried out with a quasistationary plasma accelerator QSPA Kh-50. Particular attention was paid to elaboration of damage of tungsten as a main candidate material for ITER divertor surfaces and also as prospective material for DEMO design. Erosion features, cracks evolution and changes in their thickness with increasing exposition dose are studied for different W grades, including deformed material with elongated grains, as well as WTa5 and sintered tungsten.
Overview of the negative ion based neutral beam injectors for ITER.
Schunke, B; Boilson, D; Chareyre, J; Choi, C-H; Decamps, H; El-Ouazzani, A; Geli, F; Graceffa, J; Hemsworth, R; Kushwah, M; Roux, K; Shah, D; Singh, M; Svensson, L; Urbani, M
2016-02-01
The ITER baseline foresees 2 Heating Neutral Beams (HNB's) based on 1 MeV 40 A D(-) negative ion accelerators, each capable of delivering 16.7 MW of deuterium atoms to the DT plasma, with an optional 3rd HNB injector foreseen as a possible upgrade. In addition, a dedicated diagnostic neutral beam will be injecting ≈22 A of H(0) at 100 keV as the probe beam for charge exchange recombination spectroscopy. The integration of the injectors into the ITER plant is nearly finished necessitating only refinements. A large number of components have passed the final design stage, manufacturing has started, and the essential test beds-for the prototype route chosen-will soon be ready to start. PMID:26932111
An iterative analytic—numerical method for scattering from a target buried beneath a rough surface
NASA Astrophysics Data System (ADS)
Xu, Run-Wen; Guo, Li-Xin; Wang, Rui
2014-11-01
An efficiently iterative analytical—numerical method is proposed for two-dimensional (2D) electromagnetic scattering from a perfectly electric conducting (PEC) target buried under a dielectric rough surface. The basic idea is to employ the Kirchhoff approximation (KA) to accelerate the boundary integral method (BIM). Below the rough surface, an iterative system is designed between the rough surface and the target. The KA is used to simulate the initial field on the rough surface based on the Fresnel theory, while the target is analyzed by the boundary integral method to obtain a precise result. The fields between the rough surface and the target can be linked by the boundary integral equations below the rough surface. The technique presented here is highly efficient in terms of computational memory, time, and versatility. Numerical simulations of two typical models are carried out to validate the method.
Cai, Yunfeng; Bai, Zhaojun; Pask, John E.; Sukumar, N.
2013-12-15
The iterative diagonalization of a sequence of large ill-conditioned generalized eigenvalue problems is a computational bottleneck in quantum mechanical methods employing a nonorthogonal basis for ab initio electronic structure calculations. We propose a hybrid preconditioning scheme to effectively combine global and locally accelerated preconditioners for rapid iterative diagonalization of such eigenvalue problems. In partition-of-unity finite-element (PUFE) pseudopotential density-functional calculations, employing a nonorthogonal basis, we show that the hybrid preconditioned block steepest descent method is a cost-effective eigensolver, outperforming current state-of-the-art global preconditioning schemes, and comparably efficient for the ill-conditioned generalized eigenvalue problems produced by PUFE as the locally optimal block preconditioned conjugate-gradient method for the well-conditioned standard eigenvalue problems produced by planewave methods.
He's iteration formulation for solving nonlinear algebraic equations
NASA Astrophysics Data System (ADS)
Qian, W.-X.; Ye, Y.-H.; Chen, J.; Mo, L.-F.
2008-02-01
Newton iteration method is sensitive to initial guess and its slope. To overcome the shortcoming, He's iteration method is used to solve nonlinear algebraic equations where Newton iteration method becomes invalid. Some examples are given, showing that the method is effective.
Lee, Seung Yup; Skolnick, Jeffrey
2007-07-01
To improve the accuracy of TASSER models especially in the limit where threading provided template alignments are of poor quality, we have developed the TASSER(iter) algorithm which uses the templates and contact restraints from TASSER generated models for iterative structure refinement. We apply TASSER(iter) to a large benchmark set of 2,773 nonhomologous single domain proteins that are < or = 200 in length and that cover the PDB at the level of 35% pairwise sequence identity. Overall, TASSER(iter) models have a smaller global average RMSD of 5.48 A compared to 5.81 A RMSD of the original TASSER models. Classifying the targets by the level of prediction difficulty (where Easy targets have a good template with a corresponding good threading alignment, Medium targets have a good template but a poor alignment, and Hard targets have an incorrectly identified template), TASSER(iter) (TASSER) models have an average RMSD of 4.15 A (4.35 A) for the Easy set and 9.05 A (9.52 A) for the Hard set. The largest reduction of average RMSD is for the Medium set where the TASSER(iter) models have an average global RMSD of 5.67 A compared to 6.72 A of the TASSER models. Seventy percent of the Medium set TASSER(iter) models have a smaller RMSD than the TASSER models, while 63% of the Easy and 60% of the Hard TASSER models are improved by TASSER(iter). For the foldable cases, where the targets have a RMSD to the native <6.5 A, TASSER(iter) shows obvious improvement over TASSER models: For the Medium set, it improves the success rate from 57.0 to 67.2%, followed by the Hard targets where the success rate improves from 32.0 to 34.8%, with the smallest improvement in the Easy targets from 82.6 to 84.0%. These results suggest that TASSER(iter) can provide more reliable predictions for targets of Medium difficulty, a range that had resisted improvement in the quality of protein structure predictions.
Weighted iterative reconstruction for magnetic particle imaging
NASA Astrophysics Data System (ADS)
Knopp, T.; Rahmer, J.; Sattel, T. F.; Biederer, S.; Weizenecker, J.; Gleich, B.; Borgert, J.; Buzug, T. M.
2010-03-01
Magnetic particle imaging (MPI) is a new imaging technique capable of imaging the distribution of superparamagnetic particles at high spatial and temporal resolution. For the reconstruction of the particle distribution, a system of linear equations has to be solved. The mathematical solution to this linear system can be obtained using a least-squares approach. In this paper, it is shown that the quality of the least-squares solution can be improved by incorporating a weighting matrix using the reciprocal of the matrix-row energy as weights. A further benefit of this weighting is that iterative algorithms, such as the conjugate gradient method, converge rapidly yielding the same image quality as obtained by singular value decomposition in only a few iterations. Thus, the weighting strategy in combination with the conjugate gradient method improves the image quality and substantially shortens the reconstruction time. The performance of weighting strategy and reconstruction algorithms is assessed with experimental data of a 2D MPI scanner.
Iterative most likely oriented point registration.
Billings, Seth; Taylor, Russell
2014-01-01
A new algorithm for model based registration is presented that optimizes both position and surface normal information of the shapes being registered. This algorithm extends the popular Iterative Closest Point (ICP) algorithm by incorporating the surface orientation at each point into both the correspondence and registration phases of the algorithm. For the correspondence phase an efficient search strategy is derived which computes the most probable correspondences considering both position and orientation differences in the match. For the registration phase an efficient, closed-form solution provides the maximum likelihood rigid body alignment between the oriented point matches. Experiments by simulation using human femur data demonstrate that the proposed Iterative Most Likely Oriented Point (IMLOP) algorithm has a strong accuracy advantage over ICP and has increased ability to robustly identify a successful registration result.
The Cryostat and Subsystems Development at ITER
NASA Astrophysics Data System (ADS)
Sekachev, Igor; Meekins, Michael; Sborchia, Carlo; Vitupier, Guillaume; Xie, Han; Zhou, Caipin
ITER is a large experimental tokamak being built to research fusion power. The ITER cryostat is a multifunctional system which provides vacuum insulation for the superconducting magnets operating at 4.5 K and for the thermal shield operating at 80 K. It also serves as a structural support for the tokamak and provides access ways and corridors to the vacuum vessel for diagnostic lines of sight, additional heating beams and the deployment of remote handling equipment. The cryostat has feed-through penetrations for all the equipment connecting elements of systems outside the cryostat to the corresponding elements inside the cryostat. The cryostat is a vacuum containment vessel having a very large volume of ∼16000 m3 designed to be evacuated to a base pressure of 10-4 Pa. Design details of the cryostat and associated systems, including Torus Cryopump Housing (TCPH), are discussed. Status report of the cryostat developments is presented.
Main challenges for ITER optical diagnostics
Vukolov, K. Yu.; Orlovskiy, I. I.; Alekseev, A. G.; Borisov, A. A.; Andreenko, E. N.; Kukushkin, A. B.; Lisitsa, V. S.; Neverov, V. S.
2014-08-21
The review is made of the problems of ITER optical diagnostics. Most of these problems will be related to the intensive neutron radiation from hot plasma. At a high level of radiation loads the most types of materials gradually change their properties. This effect is most critical for optical diagnostics because of degradation of optical glasses and mirrors. The degradation of mirrors, that collect the light from plasma, basically will be induced by impurity deposition and (or) sputtering by charge exchange atoms. Main attention is paid to the search of glasses for vacuum windows and achromatic lens which are stable under ITER irradiation conditions. The last results of irradiation tests in nuclear reactor of candidate silica glasses KU-1, KS-4V and TF 200 are presented. An additional problem is discussed that deals with the stray light produced by multiple reflections from the first wall of the intense light emitted in the divertor plasma.
New iterative solvers for the NAG Libraries
Salvini, S.; Shaw, G.
1996-12-31
The purpose of this paper is to introduce the work which has been carried out at NAG Ltd to update the iterative solvers for sparse systems of linear equations, both symmetric and unsymmetric, in the NAG Fortran 77 Library. Our current plans to extend this work and include it in our other numerical libraries in our range are also briefly mentioned. We have added to the Library the new Chapter F11, entirely dedicated to sparse linear algebra. At Mark 17, the F11 Chapter includes sparse iterative solvers, preconditioners, utilities and black-box routines for sparse symmetric (both positive-definite and indefinite) linear systems. Mark 18 will add solvers, preconditioners, utilities and black-boxes for sparse unsymmetric systems: the development of these has already been completed.
Main challenges for ITER optical diagnostics
NASA Astrophysics Data System (ADS)
Vukolov, K. Yu.; Orlovskiy, I. I.; Alekseev, A. G.; Borisov, A. A.; Andreenko, E. N.; Kukushkin, A. B.; Lisitsa, V. S.; Neverov, V. S.
2014-08-01
The review is made of the problems of ITER optical diagnostics. Most of these problems will be related to the intensive neutron radiation from hot plasma. At a high level of radiation loads the most types of materials gradually change their properties. This effect is most critical for optical diagnostics because of degradation of optical glasses and mirrors. The degradation of mirrors, that collect the light from plasma, basically will be induced by impurity deposition and (or) sputtering by charge exchange atoms. Main attention is paid to the search of glasses for vacuum windows and achromatic lens which are stable under ITER irradiation conditions. The last results of irradiation tests in nuclear reactor of candidate silica glasses KU-1, KS-4V and TF 200 are presented. An additional problem is discussed that deals with the stray light produced by multiple reflections from the first wall of the intense light emitted in the divertor plasma.
High contrast laminography using iterative algorithms
NASA Astrophysics Data System (ADS)
Kroupa, M.; Jakubek, J.
2011-01-01
3D X-ray imaging of internal structure of large flat objects is often complicated by limited access to all viewing angles or extremely high absorption in certain directions, therefore the standard method of computed tomography (CT) fails. This problem can be solved by the method of laminography. During a laminographic measurement the imaging detector is placed close to the sample while the X-ray source irradiates both sample and detector at different angles. The application of the state-of-the-art pixel detector Medipix in laminography together with adapted tomographic iterative alghorithms for 3D reconstruction of sample structure has been investigated. Iterative algorithms such as EM (Expectation Maximization) and OSEM (Ordered Subset Expectation Maximization) improve the quality of the reconstruction and allow including more complex physical models. In this contribution results and proposed future approaches which could be used for resolution enhancement are presented.
Huber, A.; Brezinsek, S.; Mertens, Ph.; Schweer, B.; Sergienko, G.; Terra, A.; Clever, M.; Lambertz, H. T.; Samm, U.; Arnoux, G.; Balshaw, N.; Edlingdon, T.; Farthing, J.; Matthews, G. F.; Riccardo, V.; Sanders, S.; Stamp, M.; Williams, J.; Zastrow, K. D.; and others
2012-10-15
A new endoscope with optimised divertor view has been developed in order to survey and monitor the emission of specific impurities such as tungsten and the remaining carbon as well as beryllium in the tungsten divertor of JET after the implementation of the ITER-like wall in 2011. The endoscope is a prototype for testing an ITER relevant design concept based on reflective optics only. It may be subject to high neutron fluxes as expected in ITER. The operating wavelength range, from 390 nm to 2500 nm, allows the measurements of the emission of all expected impurities (W I, Be II, C I, C II, C III) with high optical transmittance ({>=}30% in the designed wavelength range) as well as high spatial resolution that is {<=}2 mm at the object plane and {<=}3 mm for the full depth of field ({+-}0.7 m). The new optical design includes options for in situ calibration of the endoscope transmittance during the experimental campaign, which allows the continuous tracing of possible transmittance degradation with time due to impurity deposition and erosion by fast neutral particles. In parallel to the new optical design, a new type of possibly ITER relevant shutter system based on pneumatic techniques has been developed and integrated into the endoscope head. The endoscope is equipped with four digital CCD cameras, each combined with two filter wheels for narrow band interference and neutral density filters. Additionally, two protection cameras in the {lambda} > 0.95 {mu}m range have been integrated in the optical design for the real time wall protection during the plasma operation of JET.
Statistical properties of an iterated arithmetic mapping
Feix, M.R.; Rouet, J.L.
1994-07-01
We study the (3x = 1)/2 problem from a probabilistic viewpoint and show a forgetting mechanism for the last k binary digits of the seed after k iterations. The problem is subsequently generalized to a trifurcation process, the (lx + m)/3 problem. Finally the sequence of a set of seeds is empirically shown to be equivalent to a random walk of the variable log{sub 2}x (or log{sub 3} x) though computer simulations.
Iterative solutions to the Dirac equation
Ciftci, Hakan; Hall, Richard L.; Saad, Nasser
2005-08-15
We consider a single particle which is bound by a central potential and obeys the Dirac equation in d dimensions. We first apply the asymptotic iteration method to recover the known exact solutions for the pure Coulomb case. For a screened Coulomb potential and for a Coulomb plus linear potential with linear scalar confinement, the method is used to obtain accurate approximate solutions for both eigenvalues and wave functions.
Iterative solution of high order compact systems
Spotz, W.F.; Carey, G.F.
1996-12-31
We have recently developed a class of finite difference methods which provide higher accuracy and greater stability than standard central or upwind difference methods, but still reside on a compact patch of grid cells. In the present study we investigate the performance of several gradient-type iterative methods for solving the associated sparse systems. Both serial and parallel performance studies have been made. Representative examples are taken from elliptic PDE`s for diffusion, convection-diffusion, and viscous flow applications.
Iterates of a Berezin-type transform
NASA Astrophysics Data System (ADS)
Liu, Congwen
2007-05-01
Let be the open unit ball of and dV denote the Lebesgue measure on normalized so that the measure of equals 1. Suppose . The Berezin-type transform of f is defined by We prove that if then the iterates converge to the Poisson extension of the boundary values of f, as k-->[infinity]. This can be viewed as a higher dimensional generalization of a previous result obtained independently by Englis and Zhu.
Iterative pass optimization of sequence data
NASA Technical Reports Server (NTRS)
Wheeler, Ward C.
2003-01-01
The problem of determining the minimum-cost hypothetical ancestral sequences for a given cladogram is known to be NP-complete. This "tree alignment" problem has motivated the considerable effort placed in multiple sequence alignment procedures. Wheeler in 1996 proposed a heuristic method, direct optimization, to calculate cladogram costs without the intervention of multiple sequence alignment. This method, though more efficient in time and more effective in cladogram length than many alignment-based procedures, greedily optimizes nodes based on descendent information only. In their proposal of an exact multiple alignment solution, Sankoff et al. in 1976 described a heuristic procedure--the iterative improvement method--to create alignments at internal nodes by solving a series of median problems. The combination of a three-sequence direct optimization with iterative improvement and a branch-length-based cladogram cost procedure, provides an algorithm that frequently results in superior (i.e., lower) cladogram costs. This iterative pass optimization is both computation and memory intensive, but economies can be made to reduce this burden. An example in arthropod systematics is discussed. c2003 The Willi Hennig Society. Published by Elsevier Science (USA). All rights reserved.
Iterative solution of the semiconductor device equations
Bova, S.W.; Carey, G.F.
1996-12-31
Most semiconductor device models can be described by a nonlinear Poisson equation for the electrostatic potential coupled to a system of convection-reaction-diffusion equations for the transport of charge and energy. These equations are typically solved in a decoupled fashion and e.g. Newton`s method is used to obtain the resulting sequences of linear systems. The Poisson problem leads to a symmetric, positive definite system which we solve iteratively using conjugate gradient. The transport equations lead to nonsymmetric, indefinite systems, thereby complicating the selection of an appropriate iterative method. Moreover, their solutions exhibit steep layers and are subject to numerical oscillations and instabilities if standard Galerkin-type discretization strategies are used. In the present study, we use an upwind finite element technique for the transport equations. We also evaluate the performance of different iterative methods for the transport equations and investigate various preconditioners for a few generalized gradient methods. Numerical examples are given for a representative two-dimensional depletion MOSFET.
Perturbation resilience and superiorization of iterative algorithms
NASA Astrophysics Data System (ADS)
Censor, Y.; Davidi, R.; Herman, G. T.
2010-06-01
Iterative algorithms aimed at solving some problems are discussed. For certain problems, such as finding a common point in the intersection of a finite number of convex sets, there often exist iterative algorithms that impose very little demand on computer resources. For other problems, such as finding that point in the intersection at which the value of a given function is optimal, algorithms tend to need more computer memory and longer execution time. A methodology is presented whose aim is to produce automatically for an iterative algorithm of the first kind a 'superiorized version' of it that retains its computational efficiency but nevertheless goes a long way toward solving an optimization problem. This is possible to do if the original algorithm is 'perturbation resilient', which is shown to be the case for various projection algorithms for solving the consistent convex feasibility problem. The superiorized versions of such algorithms use perturbations that steer the process in the direction of a superior feasible point, which is not necessarily optimal, with respect to the given function. After presenting these intuitive ideas in a precise mathematical form, they are illustrated in image reconstruction from projections for two different projection algorithms superiorized for the function whose value is the total variation of the image.
Recent ADI iteration analysis and results
Wachspress, E.L.
1994-12-31
Some recent ADI iteration analysis and results are discussed. Discovery that the Lyapunov and Sylvester matrix equations are model ADI problems stimulated much research on ADI iteration with complex spectra. The ADI rational Chebyshev analysis parallels the classical linear Chebyshev theory. Two distinct approaches have been applied to these problems. First, parameters which were optimal for real spectra were shown to be nearly optimal for certain families of complex spectra. In the linear case these were spectra bounded by ellipses in the complex plane. In the ADI rational case these were spectra bounded by {open_quotes}elliptic-function regions{close_quotes}. The logarithms of the latter appear like ellipses, and the logarithms of the optimal ADI parameters for these regions are similar to the optimal parameters for linear Chebyshev approximation over superimposed ellipses. W.B. Jordan`s bilinear transformation of real variables to reduce the two-variable problem to one variable was generalized into the complex plane. This was needed for ADI iterative solution of the Sylvester equation.
Conformal mapping and convergence of Krylov iterations
Driscoll, T.A.; Trefethen, L.N.
1994-12-31
Connections between conformal mapping and matrix iterations have been known for many years. The idea underlying these connections is as follows. Suppose the spectrum of a matrix or operator A is contained in a Jordan region E in the complex plane with 0 not an element of E. Let {phi}(z) denote a conformal map of the exterior of E onto the exterior of the unit disk, with {phi}{infinity} = {infinity}. Then 1/{vert_bar}{phi}(0){vert_bar} is an upper bound for the optimal asymptotic convergence factor of any Krylov subspace iteration. This idea can be made precise in various ways, depending on the matrix iterations, on whether A is finite or infinite dimensional, and on what bounds are assumed on the non-normality of A. This paper explores these connections for a variety of matrix examples, making use of a new MATLAB Schwarz-Christoffel Mapping Toolbox developed by the first author. Unlike the earlier Fortran Schwarz-Christoffel package SCPACK, the new toolbox computes exterior as well as interior Schwarz-Christoffel maps, making it easy to experiment with spectra that are not necessarily symmetric about an axis.
Modelling the ITER glow discharge plasma
NASA Astrophysics Data System (ADS)
Kogut, D.; Douai, D.; Hagelaar, G.; Pitts, R. A.
2015-08-01
The ITER glow discharge cleaning (GDC) system (Maruyama et al., 2012) is aimed to prepare in-vessel component surfaces prior to the machine start-up. In order to assess glow discharge uniformity and wall coverage, thus conditioning efficiency of the system, a new 2D multi-fluid model has been developed (Hagelaar, 2012). In this work the model is compared with published experimental data on GDC wall ion fluxes in JET and RFX (Douai et al., 2013; Canton et al., 2013). The simulations of H2-GDC in ITER for the case of 1 or 2 anodes indicate a good level of homogeneity of plasma parameters in the negative glow and of the wall ion flux in the common pressure domain for GDC: 0.1-0.5 Pa. Although the model geometry does not allow simulation of all seven ITER anodes operating simultaneously, the results can be extrapolated to the full system with an average ion current density of 0.21 A/m2, which is comparable to JET (0.10 A/m2).
ITER Creation Safety File Expertise Results
NASA Astrophysics Data System (ADS)
Perrault, D.
2013-06-01
In March 2010, the ITER operator delivered the facility safety file to the French "Autorité de Sûreté Nucléaire" (ASN) as part of its request for the creation decree, legally necessary before building works can begin on the site. The French "Institut de Radioprotection et de Sûreté Nucléaire" (IRSN), in support to the ASN, recently completed its expertise of the safety measures proposed for ITER, on the basis of this file and of additional technical documents from the operator. This paper presents the IRSN's main conclusions. In particular, they focus on the radioactive materials involved, the safety and radiation protection demonstration (suitability of risk management measures…), foreseeable accidents, building and safety important component design and, finally, wastes and effluents to be produced. This assessment was just the first legally-required step in on-going safety monitoring of the ITER project, which will include other complete regulatory re-evaluations.
The dynamics of iterated transportation simulations
Nagel, K.; Rickert, M.; Simon, P.M.
1998-12-01
Transportation-related decisions of people often depend on what everybody else is doing. For example, decisions about mode choice, route choice, activity scheduling, etc., can depend on congestion, caused by the aggregated behavior of others. From a conceptual viewpoint, this consistency problem causes a deadlock, since nobody can start planning because they do not know what everybody else is doing. It is the process of iterations that is examined in this paper as a method for solving the problem. In this paper, the authors concentrate on the aspect of the iterative process that is probably the most important one from a practical viewpoint, and that is the ``uniqueness`` or ``robustness`` of the results. Also, they define robustness more in terms of common sense than in terms of a mathematical formalism. For this, they do not only want a single iterative process to converge, but they want the result to be independent of any particular implementation. The authors run many computational experiments, sometimes with variations of the same code, sometimes with totally different code, in order to see if any of the results are robust against these changes.
Acceleration of convergence of vector sequences
NASA Technical Reports Server (NTRS)
Sidi, A.; Ford, W. F.; Smith, D. A.
1983-01-01
A general approach to the construction of convergence acceleration methods for vector sequence is proposed. Using this approach, one can generate some known methods, such as the minimal polynomial extrapolation, the reduced rank extrapolation, and the topological epsilon algorithm, and also some new ones. Some of the new methods are easier to implement than the known methods and are observed to have similar numerical properties. The convergence analysis of these new methods is carried out, and it is shown that they are especially suitable for accelerating the convergence of vector sequences that are obtained when one solves linear systems of equations iteratively. A stability analysis is also given, and numerical examples are provided. The convergence and stability properties of the topological epsilon algorithm are likewise given.
40 CFR 180.438 - Lambda-cyhalothrin and an isomer gamma-cyhalothrin; tolerances for residues.
Code of Federal Regulations, 2013 CFR
2013-07-01
... 40 Protection of Environment 25 2013-07-01 2013-07-01 false Lambda-cyhalothrin and an isomer gamma... FOOD Specific Tolerances § 180.438 Lambda-cyhalothrin and an isomer gamma-cyhalothrin; tolerances for... established for the combined residues of the pyrethroid [gamma-cyhalothrin (the isolated active isomer...
40 CFR 180.438 - Lambda-cyhalothrin and an isomer gamma-cyhalothrin; tolerances for residues.
Code of Federal Regulations, 2014 CFR
2014-07-01
... 40 Protection of Environment 24 2014-07-01 2014-07-01 false Lambda-cyhalothrin and an isomer gamma... FOOD Specific Tolerances § 180.438 Lambda-cyhalothrin and an isomer gamma-cyhalothrin; tolerances for... established for the combined residues of the pyrethroid [gamma-cyhalothrin (the isolated active isomer...
40 CFR 180.438 - Lambda-cyhalothrin and an isomer gamma-cyhalothrin; tolerances for residues.
Code of Federal Regulations, 2010 CFR
2010-07-01
... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Lambda-cyhalothrin and an isomer gamma... FOOD Specific Tolerances § 180.438 Lambda-cyhalothrin and an isomer gamma-cyhalothrin; tolerances for... established for the combined residues of the pyrethroid [gamma-cyhalothrin (the isolated active isomer...
40 CFR 180.438 - Lambda-cyhalothrin and an isomer gamma-cyhalothrin; tolerances for residues.
Code of Federal Regulations, 2011 CFR
2011-07-01
... 40 Protection of Environment 24 2011-07-01 2011-07-01 false Lambda-cyhalothrin and an isomer gamma... FOOD Specific Tolerances § 180.438 Lambda-cyhalothrin and an isomer gamma-cyhalothrin; tolerances for... established for the combined residues of the pyrethroid [gamma-cyhalothrin (the isolated active isomer...
40 CFR 180.438 - Lambda-cyhalothrin and an isomer gamma-cyhalothrin; tolerances for residues.
Code of Federal Regulations, 2012 CFR
2012-07-01
... 40 Protection of Environment 25 2012-07-01 2012-07-01 false Lambda-cyhalothrin and an isomer gamma... FOOD Specific Tolerances § 180.438 Lambda-cyhalothrin and an isomer gamma-cyhalothrin; tolerances for... established for the combined residues of the pyrethroid [gamma-cyhalothrin (the isolated active isomer...
NASA Technical Reports Server (NTRS)
Zirin, H.
1975-01-01
Measurements of the lambda 1030 He line in 198 stars are given along with data on other features in that spectral range. Nearly 80% of all G and K stars show some lambda 10830; of these, half are variable and 1/4 show emission. It was confirmed that lambda 10830 is not found in M stars, is weak in F stars, and is particularly strong in close binaries. The line is found in emission in extremely late M and S stars, along with P gamma, but P gamma is not in emission in G and K stars with lambda 10830 emissions. Variable He emission and Ti I emission are found in the RV Tauri variables R Scuti and U Mon. In R Aqr the Fe XIII coronal line lambda 10747 and a line at lambda 11012 which may be singlet He or La II are found, as well as lambda 10830 and P gamma. The nature of coronas or hot chromospheres in the various stars is discussed. It was concluded that the lambda 10830 intensity must be more or less proportional to the energy deposited in the chromosphere corona by non-thermal processes.
The influence of initial temperature on flame acceleration and deflagration-to-detonation transition
Ciccarelli, G.; Boccio, J.L.; Ginsberg, T.
1996-07-01
The influence of initial mixture temperature on deflagration-to-detonation transition (DDT) has been investigated experimentally. The experiments were carried out in a 27-cm-inner diameter, 21.3-meter-long heated detonation tube, which was equipped with periodic orifice plates to promote flame acceleration. Hydrogen-air-steam mixtures were tested at a range of temperatures up to 650K and at an initial pressure of 0.1 MPa. In most cases, the limiting hydrogen mole fraction which resulted in transition to detonation corresponded to the mixture whose detonation cell size, {lambda}, was approximately equal to the inner diameter of the orifice plate, d (e.g., d/{lambda}{approximately}1). The only exception was in dry hydrogen-air mixtures at 650K where the DDT limit was observed to be 11 percent hydrogen, corresponding to a value of d/{lambda} equal to 5.5. For a 10.5 percent hydrogen mixture at 650K, the flame accelerated to a maximum velocity of about 120 m/s and then decelerated to below 2 m/s. This observation indicates that the d/{lambda} = 1 DDT limit criterion provides a necessary condition but not a sufficient one for the onset of DDT in obstacle-laden ducts. In this particular case, the mixture initial condition (i.e., temperature) resulted in the inability of the mixture to sustain flame acceleration to the point where DDT could occur. It was also observed that the distance required for the flame to accelerate to the onset of detonation was a function of both the hydrogen mole fraction and the mixture initial temperature. For example, decreasing the hydrogen mole fraction or increasing the initial mixture temperature resulted in longer transition distances.
Zhang, S.; Zu, Z.; Chen, J.H., Ma, Y.G., Cai, X-Z, Ma, G.L., Zhong, C.
2011-08-01
High-energy heavy-ion collisions produce abundant hyperons and nucleons. A dynamical coalescence model coupled with the ART model is employed to study the production probabilities of light clusters, deuteron (d), triton (t), helion ({sup 3}He), and hypertriton ({sub {Lambda}}{sup 3}H) at subthreshold energy of Aproduction ({approx} 1 GeV per nucleon). We study the dependence on the reaction system size of the coalescence penalty factor per additional nucleon and entropy per nucleon. The Strangeness Population Factor (S{sub 3} = {sup 3}{sub {Lambda}}H/({sup 3}He x {Lambda}/p)) shows an extra suppression of hypertriton comparing to light clusters of the same mass number. This model predicts a hypertriton production cross-section of a few {mu}b in {sup 36}Ar+{sup 36}Ar, {sup 40}Ca+{sup 40}Ca and {sup 56}Ni+{sup 56}Ni in 1 A GeV reactions. The production rate is as high as a few hypertritons per million collisions, which shows that the fixed-target heavy-ion collisions at CSR (Lanzhou/China) at {Lambda} subthreshold energy are suitable for breaking new ground in hypernuclear physics.
Low-lying {Lambda} baryons with spin 1/2 in two-flavor lattice QCD
Takahashi, Toru T.; Oka, Makoto
2010-02-01
Low-lying {Lambda} baryons with spin 1/2 are analyzed in full (unquenched) lattice QCD. We construct 2x2 cross correlators from flavor SU(3) octet and singlet baryon operators, and diagonalize them so as to extract information of two low-lying states for each parity. The two-flavor CP-PACS gauge configurations are used, which are generated in the renormalization-group improved gauge action and the O(a)-improved quark action. Three different {beta}'s, {beta}=1.80, 1.95, and 2.10, are employed, whose corresponding lattice spacings are a=0.2150, 0.1555, and 0.1076 fm. For each cutoff, we use four hopping parameters, ({kappa}{sub val},{kappa}{sub sea}), which correspond to the pion masses ranging about from 500 MeV to 1.1 GeV. Results indicate that there are two negative-parity {Lambda} states nearly degenerate at around 1.6 GeV, while no state as low as {Lambda}(1405) is observed. By decomposing the flavor components of each state, we find that the lowest (1st-excited) negative-parity state is dominated by flavor-singlet (flavor-octet) component. We also discuss meson-baryon components of each state, which has drawn considerable attention in the context of multiquark pictures of {Lambda}(1405).
Hydroponic Uptake of Atrazine and Lambda-cyhalothrin in Aquatic Macrophytes
NASA Astrophysics Data System (ADS)
Bouldin, J. L.; Farris, J. L.; Moore, M. T.; Smith, S.; Cooper, C. M.
2005-05-01
Phytoremediation encompasses an array of plant-associated processes known to mitigate contaminants from soil, sediment, and water. Modification of pesticides associated with agricultural runoff includes processes directly associated with aquatic macrophytes in addition to soil geochemical modifications and associated rhizospheric degradation. Remediation attributes of two vegetative species common to agricultural drainages in the Mississippi Delta, USA, were assessed using atrazine and lambda-cyhalothrin. Concentrations used in 8-d hydroponic exposures were calculated using recommended field applications and a 5% runoff model from a 0.65-cm rainfall event on a 2.02-ha field. While greater atrazine uptake was measured in Juncus effusus, greater lambda-cyhalothrin uptake occurred in Ludwigia peploides. Maximum pesticide uptake was reached within 48 h for each exposure and subsequent translocation of pesticides to upper plant biomass occurred in macrophytes exposed to atrazine. Sequestration of 98.2% of lambda-cyhalothrin in roots of L. peploides was measured after 8 d. Translocation of lambda-cyhalothrin in J. effusus resulted in 25.4% of pesticide uptake partitioned to upper plant biomass. These individual macrophyte remediation studies measured species- and pesticide-specific uptake rates, indicating that the seasonality of pesticide applications and macrophyte emergence might interact strongly to enhance mitigation capabilities in edge-of-field conveyance structures.
Structural and dynamical aspects of avoided-crossing resonances in a three-level {Lambda} system
Lizuain, I.; Echanobe, J.; Ruschhaupt, A.; Muga, J. G.; Steck, D. A.
2010-12-15
In a recent publication [Phys. Rev. A 79, 065602 (2009)], it was shown that an avoided-crossing resonance can be defined according to level-structural or dynamical criteria. We propose an experiment to observe the difference between the two definitions in a three-level {Lambda} system using microwave fields coupling hyperfine magnetic sublevels in alkali-metal atoms.
An addition at the C-terminus of water-buffalo immunoglobin lambda chains.
Svasti, J
1977-01-01
The amino acid sequence of the C-terminal tryptic peptide of pooled water-buffalo immunoglobulin lambda chains was determined as Thr-Val-Lys-Pro-Ser-Glu-Cys-Pro-Ser. This sequence is closely homologous to equivalent sequences from other species, but shows an additional amino acid on the C-terminal side of the interchain half-cystine residue.
Deb, S; Bandyopadhyay, S; Roy, S
2000-03-28
Binding of regulatory proteins to multipartite DNA binding sites often occurs with protein-protein interaction, resulting in cooperative binding. The operators of bacteriophage lambda have several pairs of repressor binding sites (O(R)1-O(R)2, O(R)2-O(R)3, O(L)1-O(L)2, and O(L)2-O(L)3) separated by a variable number of base pairs, and thus, bacteriophage lambda is a model system for studying multipartite operator recognition by DNA-binding proteins. Near-UV circular dichroism spectra show that the DNA is distorted in O(R)1-O(R)2 and O(L)2-O(L)3 but much less so in O(R)2-O(R)3. Upon titration of lambda-repressor with single-operator sites O(R)1, O(R)2, and O(R)3, it was observed that the tryptophan fluorescence quenches to different degrees, suggesting different conformations of the protein in the three DNA-protein complexes. Acrylamide quenching of tryptophan fluorescence of lambda-repressor bound to these single operators also shows different Stern-Volmer constants, supporting the above conclusions. Titration of lambda-repressor with oligonucleotides containing pairs of operator sites also causes different degrees of fluorescence quenching. In particular, fluorescence quenching induced by O(R)1-O(R)2 binding is less than the quenching induced by either of the single operators alone, suggesting additional conformational changes upon establishment of protein-protein contact. Stern-Volmer constants obtained from acrylamide quenching of tryptophan fluorescence of lambda-repressor bound cooperatively to pairs of operator sites are different from those of the single-operator-site-bound repressors. For example, O(R)2-O(R)3-bound repressor has significantly higher acrylamide quenchable components than either of the O(R)2- or O(R)3-bound proteins, again suggesting additional conformational changes upon establishment of protein-protein contact. We conclude that the strategy of recognition of multipartite operator by lambda-repressor is complex and varied, involving
Evaluation of ITER MSE Viewing Optics
Allen, S; Lerner, S; Morris, K; Jayakumar, J; Holcomb, C; Makowski, M; Latkowski, J; Chipman, R
2007-03-26
The Motional Stark Effect (MSE) diagnostic on ITER determines the local plasma current density by measuring the polarization angle of light resulting from the interaction of a high energy neutral heating beam and the tokamak plasma. This light signal has to be transmitted from the edge and core of the plasma to a polarization analyzer located in the port plug. The optical system should either preserve the polarization information, or it should be possible to reliably calibrate any changes induced by the optics. This LLNL Work for Others project for the US ITER Project Office (USIPO) is focused on the design of the viewing optics for both the edge and core MSE systems. Several design constraints were considered, including: image quality, lack of polarization aberrations, ease of construction and cost of mirrors, neutron shielding, and geometric layout in the equatorial port plugs. The edge MSE optics are located in ITER equatorial port 3 and view Heating Beam 5, and the core system is located in equatorial port 1 viewing heating beam 4. The current work is an extension of previous preliminary design work completed by the ITER central team (ITER resources were not available to complete a detailed optimization of this system, and then the MSE was assigned to the US). The optimization of the optical systems at this level was done with the ZEMAX optical ray tracing code. The final LLNL designs decreased the ''blur'' in the optical system by nearly an order of magnitude, and the polarization blur was reduced by a factor of 3. The mirror sizes were reduced with an estimated cost savings of a factor of 3. The throughput of the system was greater than or equal to the previous ITER design. It was found that optical ray tracing was necessary to accurately measure the throughput. Metal mirrors, while they can introduce polarization aberrations, were used close to the plasma because of the anticipated high heat, particle, and neutron loads. These mirrors formed an intermediate
Abulencia, A.; Acosta, D.; Adelman, Jahred A.; Affolder, Anthony A.; Akimoto, T.; Albrow, M.G.; Ambrose, D.; Amerio, S.; Amidei, D.; Anastassov, A.; Anikeev, K.; /Taiwan, Inst. Phys. /Argonne /Barcelona, IFAE /Baylor U. /INFN, Bologna /Bologna U. /Brandeis U. /UC, Davis /UCLA /UC, San Diego /UC, Santa Barbara
2006-01-01
The authors present the first observation of the baryon decay {Lambda}{sub b}{sup 0} {yields} {Lambda}{sub c}{sup +} {pi}{sup -} followed by {Lambda}{sub c}{sup +} {yields} pK{sup -} {pi}{sup +} in 106 pb{sup -1} p{bar p} collisions at {radical}s = 1.96 TeV in the CDF experiment. IN order to reduce systematic error, the measured rate for {Lambda}{sub b}{sup 0} decay is normalized to the kinematically similar meson decay {bar B}{sup 0} {yields} D{sup +}{pi}{sup -} followed by D{sup +} {yields} {pi}{sup +}K{sup -}{pi}{sup +}. They report the ratio of production cross sections ({sigma}) times the ratio of branching fractions ({Beta}) for the momentum region integrated above p{sub T} > 6 GeV/c and pseudorapidity range |{eta}| < 1.3: {sigma}(p{bar p} {yields} {Lambda}{sub b}{sup 0}X)/{sigma}(p{bar p} {yields} {bar B}{sup 0} X) x {Beta}({Lambda}{sub b}{sup 0} {yields} {Lambda}{sub c}{sup +}{pi}{sup -})/{Beta}({bar B}{sup 0} {yields} D{sup +}{pi}{sup -}) = 0.82 {+-} 0.08(stat) {+-} 0.11(syst) {+-} 0.22 ({Beta}({Lambda}{sub c}{sup +} {yields} pK{sup -} {pi}{sup +})).
Demons deformable registration of CT and cone-beam CT using an iterative intensity matching approach
Nithiananthan, Sajendra; Schafer, Sebastian; Uneri, Ali; and others
2011-04-15
Purpose: A method of intensity-based deformable registration of CT and cone-beam CT (CBCT) images is described, in which intensity correction occurs simultaneously within the iterative registration process. The method preserves the speed and simplicity of the popular Demons algorithm while providing robustness and accuracy in the presence of large mismatch between CT and CBCT voxel values (''intensity''). Methods: A variant of the Demons algorithm was developed in which an estimate of the relationship between CT and CBCT intensity values for specific materials in the image is computed at each iteration based on the set of currently overlapping voxels. This tissue-specific intensity correction is then used to estimate the registration output for that iteration and the process is repeated. The robustness of the method was tested in CBCT images of a cadaveric head exhibiting a broad range of simulated intensity variations associated with x-ray scatter, object truncation, and/or errors in the reconstruction algorithm. The accuracy of CT-CBCT registration was also measured in six real cases, exhibiting deformations ranging from simple to complex during surgery or radiotherapy guided by a CBCT-capable C-arm or linear accelerator, respectively. Results: The iterative intensity matching approach was robust against all levels of intensity variation examined, including spatially varying errors in voxel value of a factor of 2 or more, as can be encountered in cases of high x-ray scatter. Registration accuracy without intensity matching degraded severely with increasing magnitude of intensity error and introduced image distortion. A single histogram match performed prior to registration alleviated some of these effects but was also prone to image distortion and was quantifiably less robust and accurate than the iterative approach. Within the six case registration accuracy study, iterative intensity matching Demons reduced mean TRE to (2.5{+-}2.8) mm compared to (3.5{+-}3.0) mm
NASA Astrophysics Data System (ADS)
Velikina, J. V.; Samsonov, A. A.
2016-02-01
Advanced MRI techniques often require sampling in additional (non-spatial) dimensions such as time or parametric dimensions, which significantly elongate scan time. Our purpose was to develop novel iterative image reconstruction methods to reduce amount of acquired data in such applications using prior knowledge about signal in the extra dimensions. The efforts have been made to accelerate two applications, namely, time resolved contrast enhanced MR angiography and T1 mapping. Our result demonstrate that significant acceleration (up to 27x times) may be achieved using our proposed iterative reconstruction techniques.
A quasi-Newton acceleration for high-dimensional optimization algorithms.
Zhou, Hua; Alexander, David; Lange, Kenneth
2011-01-01
In many statistical problems, maximum likelihood estimation by an EM or MM algorithm suffers from excruciatingly slow convergence. This tendency limits the application of these algorithms to modern high-dimensional problems in data mining, genomics, and imaging. Unfortunately, most existing acceleration techniques are ill-suited to complicated models involving large numbers of parameters. The squared iterative methods (SQUAREM) recently proposed by Varadhan and Roland constitute one notable exception. This paper presents a new quasi-Newton acceleration scheme that requires only modest increments in computation per iteration and overall storage and rivals or surpasses the performance of SQUAREM on several representative test problems.