WorldWideScience
1

Kaluza-Klein Higher Derivative Induced Gravity  

CERN Document Server

Kaluza-Klein higher derivative induced gravity is studied for its application in the inflationary universe. The stability of an inflationary solution in a $D+4$-dimensional anisotropic space is analyzed carefully. We show that there is two nontrivial constraints derived from the static assumptions on the $D$-dimensional scale factor $d$ and scalar field $\\psi$. We find that a physical inflationary solution is consistent with the above constraints. In addition, a compact formula for the non-redundant $4+D$ dimensional Friedmann equation is also derived for convenience. Possible implications are also discussed in this paper.

2006-01-01

2

Higher spin symmetries and w_#infinity# algebra in the conformal affine Toda model  

International Nuclear Information System (INIS)

As recently shown the conformal affine Toda models can be obtained via hamiltonian reduction from a two-loop Kac-Moody algebra. In this paper we propose a systematic procedure to analyze the higher spin symmetries of the conformal affine Toda models. The method is based on an explicit construction of infinite towers of extended conformal symmetry generators. Two fundamental building blocks of this construction are special spin-one and -two primary fields characterizing the conformal structure of these models. The connection to the algebra of area preserving diffeomorphisms on a two-manifold (w_#infinity# algebra) is established. (orig.).

1992-05-01

3

Unifying the Strengths of Forces in Higher Dimensions  

CERN Document Server

We consider the embedding of the Standard Model fields in a$(4+d)$-dimensional theory while gravitons may propagate in $d'$ extra, compactdimensions. We study the modification of strengths of the gravitational andgauge interactions and, for various values of $d$ and $d'$, we determine theenergy scale at which these strengths are unified. Special cases where theunification of strengths is characterized by the absence of any hierarchyproblem are also presented.

2000-01-01

4

Infinite dimensional algebra for all the (super-)field theories in four dimensions  

International Nuclear Information System (INIS)

By reformulating the usual free massless field theories in terms of twistors we get systems which are invariant under an infinite dimensional algebra. This algebra contains the two-dimensional conformal algebra and the SU(2, 2) algebra as subalgebras. It turns out that these systems, which possess the four-dimensional complex manifold structure of the twistor space, can lead to a natural generalization of the notion of two-dimensional conformal field theories to four dimensions. (orig.).

1989-12-01

5

Representation blocks of conformal fields for the N=4 SU(2)$_{k}$ superconformal algebras  

CERN Document Server

The representation theories of the SU(2).sub(k)-extended N=4 superconformal algebras (SCAs) with arbitrary level k are developed being based on their Feigin-Fuchs representations found recently by the present author. A basic unit of the representation blocks consisting of eight \\lq\\lq boson-like\\rq\\rq\\ and eight \\lq\\lq fermion-like\\rq\\rq\\ conformal fields is found to describe arbitrary representations of the $N$=4 SU(2)$_k$ SCAs, including {\\it unitary} and {\\it nonunitary} representations. The transformation properties of the fundamental sets of the conformal fields under the $N$=4 SU(2)$_k$ superconformal symmetries are given. Then, the whole sets of the charge-screening operators of the $N$=4 SU(2)$_k$ SCAs are identified out of the sixteen conformal fields in the basic unit of the representation blocks. The conditions for the {\\it eligible} ...

1994-01-01

6

Exchange algebra and the Drinfeld-Sokolov theorem  

International Nuclear Information System (INIS)

We analyse the relation between the exchange algebra and the separation of the chiralities in classical Toda field theory. We show that there exists a conformally covariant Bloch wave basis such that the two chiralities commute. In terms of this basis we then reconstruct the periodic and local solution of Toda field theory. (orig.).

1991-01-01

7

Scaling dimensions in hidden Kerr/CFT  

CERN Document Server

It has been proposed that a hidden conformal field theory (CFT) governs the dynamics of low frequency scattering in a general Kerr black hole background. We further investigate this correspondence by mapping higher order corrections to the massless wave equations in a Kerr background to an expansion within the CFT in terms of higher dimension operators. This implies the presence of infinite towers of CFT primary operators with positive conformal dimensions compatible with unitarity. The exact Kerr background softly breaks the conformal symmetry and the scaling dimensions of these operators run with frequency. The scale-invariant fixed point is dual to a degenerate case of flat spacetime.

2011-01-01

8

Infinite-parametric extension of the conformal algebra in D>2 space-time dimensions  

International Nuclear Information System (INIS)

On the basis of the analytic continuations of semisimple Lie algebras discovered recently by us we construct manifestly quasiconformal infinite-dimensional algebras AC(so(4, 1)) and PAC(so(3, 2)) extending the conformal algebras in three-dimensional euclidean and Minkowski space-time like the Virasoro algebra extends so(2, 1). Their higher spin generalizations are also constructed. A counterpart of the central extension for D > 2 and possible appplications in exactly solvable conformal quantum field models in D > 2 are discussed. (orig.).

1991-01-01

9

A dose computation algorithm used in MLC conformal treatment  

International Nuclear Information System (INIS)

A dose calculation algorithm for MLC based conformal radiotherapy is described in this paper. The algorithm is formulated by the coordinate of MLC leaves. Verification on the algorithm is made by comparing the dose distributions generated by this algorithm with that generated by a Differential Convolution Superposition algorithm for various regular and irregular fields. The results demonstrate that the present algorithm has suitable accuracy and high computational efficiency, thus it could be useful for the treatment planning process in MLC based conformal radiotherapy, where the workload for interactively or automatically designing the shapes of MLC is heavy. (authors)

2007-12-01

10

q-Virasoro algebra, q-conformal dimensions and free q-superstring  

International Nuclear Information System (INIS)

The commutators of standard Virasoro generators and fields generate various representations of the centreless Virasoro algebra depending on a conformal dimension J of the field in question (J is related to the Bargmann index of SU(1,1) generated by L_m, m=0,#+-#1). We introduce the notion of q-conformal dimension for various oscillator realizations of q-deformed Virasoro (super)algebras proposed earlier. We use the field theoretical approach introduced recently in which the q-Virasoro currents L"#alpha# (z) are expressed as Schwinger-like point-split normally ordered quadratic expressions in elementary fields. We extend this approach and probe the elementary fields A(z) (the q-superstring coordinate, momentum and fermionic field) and their powers by the q-Virasoro generators L"#alpha#_m (i.e. we calculate the commutators ...

1996-12-01

11

Conformal field theories via Hamiltonian reduction  

International Nuclear Information System (INIS)

Constraining the SL(3) WZW-model we construct a reduced theory which is invariant with respect to the new chiral algebra W_3"2. This symmetry is generated by the stress-energy tensor, two bosonic currents with spins 3/2 and the U(1) current. We conjecture a Kac formula that describes the highly reducible representation for this algebra. We also discuss the quantum Hamiltonian reduction for the general type of constraints that leads to the new extended conformal algebras. (orig.).

1991-01-01

12

Bosonization of conformal ghosts in Witten's string theory  

International Nuclear Information System (INIS)

It is formulated Witten's proposal of a covariant open-string theory in terms of oscillator modes and shown that some basic axioms for the noncommutative geometry are obeyed as algebraic operations, which were defined previously from a geometrical point of view. Our strategy is based on the proper bosonization of the conformal ghost fields.

13

Operator algebra from fusion rules. Pt. 2  

International Nuclear Information System (INIS)

The classification of rational conformal field theories is essentially equivalent to the classification of all possible four-point functions for the primary fields of the theories. An interesting set of parameters appearing in the latter classification is given by the number and the positions of so-called apparent singularities of the differential equations which are obeyed by the four-point functions. The subject of this paper is a detailed analysis of the role played by these parameters. In particular the restrictions imposed on them by general principles of two-dimensional conformal field theory are worked out, and the implications on the classification programme are discussed. (orig.).

1992-11-01

14

Quantum group structure in the unitary minimal model  

Energy Technology Data Exchange (ETDEWEB)

We obtain a symmetry algebra for any unitary minimal model by using the representation of conformal field theories. This symmetry algebra can be interpreted as a quantum group. The generalization to non-unitary minimal models is direct. (orig.).

1989-10-05

15

Quantum group structure in the unitary minimal model  

International Nuclear Information System (INIS)

We obtain a symmetry algebra for any unitary minimal model by using the representation of conformal field theories. This symmetry algebra can be interpreted as a quantum group. The generalization to non-unitary minimal models is direct. (orig.).

16

Open descendants in conformal field theory  

International Nuclear Information System (INIS)

Open descendants extend conformal field theory to unoriented surfaces with boundaries. The construction rests on two types of generalizations of the fusion algebra. The first is needed even in the relatively simple case of diagonal models. It leads to a new tensor that satisfies the fusion algebra, but whose entries are signed integers. The second is needed when dealing with non-diagonal models, where Cardy's ansatz does not apply. It leads to a new tensor with positive integer entries, that satisfies a set of polynomial equations and encodes the classification of the allowed boundary operators. (orig.).

1995-12-01

17

W algebras in conformal quantum field theory  

International Nuclear Information System (INIS)

A new algorithm for constructing extensions of the Virasoro algebra by primary fields - so called W-algebras - is presented. With the help of REDUCE all W-algebras with one further primary field up to conformal dimension 9 were calculated. Furthermore I give an interpretation of the obtained results using fusion algebras. The algorithm could also be used for constructing extensions of the super Virasoro algebra which play an important role in superstring theory. I present two examples here. With using representation theory of Kac-Moody algebras I determine the minimal field content of the super W_3 algebra. Finally, the general coset models SU(2)_kxSU(2)_m/SU(2)_k_+_m and SU(3)_kxSU(3)_m/SU(3)_k_+m are investigated. I calculate which W-algebras are likely contained in these cosets. (orig.).

1991-01-01

18

Fusion algebras of fermionic rational conformal field theories via a generalized Verlinde formula  

International Nuclear Information System (INIS)

We prove a generalization of the Verlinde formula to fermionic rational conformal field theories. The fusion coefficients of the fermionic theory are equal to sums of fusion coefficients of its bosonic projection. In particular, fusion coefficients of the fermionic theory connecting two conjugate Ramond fields with the identity are either one or two. Therefore, one is forced to weaken the axioms of fusion algebras for fermionic theories. We show that in the special case of fermionic W(2, #delta#)-algebras these coefficients are given by the dimensions of the irreducible representations of the horizontal subalgebra on the highest weight. As concrete examples we discuss fusion algebras of rational models of fermionic W(2, #delta#)-algebras including minimal models of the N = 1 super Virasoro algebra as well as N = 1 super W-algebras SW(3/2, #delta#). (orig.).

1994-02-01

19

Vertex operator representation of OS/sub rho/(M/N)/sup (1)/  

Energy Technology Data Exchange (ETDEWEB)

Using the boson-fermion equivalence in 2-d conformal field theory and the boson-boson equivalence of the superconformal bosonic ghost fields of the string theory, the authors construct a level {Kappa} = +1 representation of the affine superalgebra OSp(M*N)/sup 1/ in terms of vertex operators.

1988-01-01

20

Bosonic realization of a universal W-algebra and Z_#infinity# parafermions  

International Nuclear Information System (INIS)

We construct a field theoretic representation of the universal W-algebra proposed by Pope, Romans and Shen, using a free complex boson in two dimensions. The resulting symmetry algebra is generated by conformal fields with spin 2, 3, 4, ... and has central charge c=2. Highest-weight representations are also given in terms of vertex operators. Furthermore, we discuss the relation of this representation to the theory of Z_#infinity# parafermions. (orig.).

1990-10-01

21

Strings through the Microscope  

CERN Document Server

Over the last few years, string theory has changed profoundly. Most importantly, novel duality relations have emerged which involve gauge theories of brane excitations on one side and various closed string backgrounds on the other. In this lecture, we introduce the fundamental ingredients of modern string theory and explain how they are modeled through 2D (boundary) conformal field theory. This so-called `microscopic description' of strings and branes is an active research area with new results ranging from the classification and construction of boundary conditions to studies of 2D renormalization group flows. We shall provide an overview of such developments before concluding the lecture with an extensive outlook on some research that is motivated by current problems in string theory. This includes investigations of non-rational and non-unitary conformal field theories.

2004-01-01

22

Two-dimensional (half-) integer spin conformal theories with central charge c < 1  

Energy Technology Data Exchange (ETDEWEB)

A generalized integral representation involving two types of charges is explored to construct correlation functions on the plane for c = 1 - 6/(m(m + 1)) < 1 discrete unitary Virasoro series. The various local operator product algebras emerging contain integer, or half-integer, spin fields along with scalar fields. The examples also include a generalization for arbitrary m of the Z/sub 2/sup -// statistics of the Ising model order-disorder fields.

1988-01-01

23

Initiation of conformal radiotherapy with a multileaf-collimator - An approach to clinical routine  

International Nuclear Information System (INIS)

The implementation of a three-dimensional conformal radiotherapy facility in the radiotherapy department of the Heinrich Heine University is described. Complex radiotherapy techniques with commercially available networked systems are introduced to improve clinical work. Over 18 month we have gained clinical experience with a PHILIPS Multileaf Collimator (MLC) mounted on a SL 25 linear accelerator. For a limited period the MLC was used as a conventional blocking device. The standard MLC-shapes are controlled with a stand-alone computer system. In addition, a three-dimensional treatment planning system (3-D-TPS / TMS-Radix, Helax AB) based on convolution/superposition algorithms was recently installed. Treatment optimization is achieved using static field arrangements with complete volumetric computerized tomographic patient data for 3-D-TPS. Conformal adaptation of the 95%-isodose to the Planning Target Volume (PTV, ICRU 50) ...

1995-10-01

24

Inflation in a renormalizable cosmological model and the cosmic no-hair conjecture  

Energy Technology Data Exchange (ETDEWEB)

The possibility of having inflation in a renormalizable cosmological model is investigated. The cosmic no-hair conjecture is proved to hold for all Bianchi types except Bianchi type IX. By the use of a conformal transformation on the metric we show that these models are equivalent to the ones described by the Einstein-Hilbert action for gravity minimally coupled to a set of scalar fields with inflationary potentials. Henceforth, we prove that inflationary solutions behave as attractors in solution space, making it a natural event in the evolution of such models.

1989-05-15

25

Inflation in a renormalizable cosmological model and the cosmic no-hair conjecture  

International Nuclear Information System (INIS)

The possibility of having inflation in a renormalizable cosmological model is investigated. The cosmic no-hair conjecture is proved to hold for all Bianchi types except Bianchi type IX. By the use of a conformal transformation on the metric we show that these models are equivalent to the ones described by the Einstein-Hilbert action for gravity minimally coupled to a set of scalar fields with inflationary potentials. Henceforth, we prove that inflationary solutions behave as attractors in solution space, making it a natural event in the evolution of such models.

26

A simple model of dimensional collapse  

CERN Document Server

We consider a simple model of d families of scalar field interacting with geometry in two dimensions. The geometry is locally flat and has only global degrees of freedom. When d0 it collapses to a one dimensional manifold. The model has some, but not all, of the characteristics believed to be features of the full theory of conformal matter interacting with quantum gravity which has local geometric degrees of freedom.

1996-01-01

27

Conjugate variables in quantum field theory: the basic case  

CERN Document Server

Within standard quantum field theory of one scalar field we define operators conjugate to the energy-momentum operators of the theory. They are singled out by calculational simplicity in Fock space. In terms of the underlying scalar field they are non-local. We establish their algebra where it turns out that time and space operators do not commute. Their transformation properties with respect to the conformal group are derived. Solving their eigenvalue problem permits to reconstruct the Fock space in terms of the eigenstates. It is indicated how Paulis theorem may be circumvented. As an application we form the analogue of S-matrices which yields information on the structure of the underlying spacetime. Similarly we define fields and look at their equations of motion.

2010-01-01

28

W_3-algebra constructed from the SU(3) parafermion  

International Nuclear Information System (INIS)

A construction of a W_3-algebra for the SU(3) parafermion is proposed. The details of the calculation are given, in which the Z-algebra technique is used instead of the popular free field realization. We find that the W_3-algebra is closed at level k=3, and the central charge of the underlying algebra is different from known series of Fateev-Lykyanov W-algebras; as a by-product we get a field T"("4")(z), whose conformal dimension is 4, and is null at k=3. ((orig.)).

8730-01-01

29

Design and field trial application of foam in production wells to improve conformance  

Energy Technology Data Exchange (ETDEWEB)

Many of the vertical hydrocarbon miscible floods in the Keg River carbonate reefs of the Rainbow Field are at a mature stage of reservoir depletion, and are characterized by thin oil sandwiches. Injection of a gas-blocking foam barrier into a gas cone had the potential to improve oil productivity. Experimental foam treatments were described for two wells, each in a different miscible flood well. One of the wells received foam in an aqueous solution to generate foam in-situ, and as a surface generated foam. These attempt were unsuccessful at improving well performance. The second well was injected with preformed foam only. This treatment reduced GOR and improved oil production over a 14 month period. Field experience from these field trials was expected to improve efficiency in planning, design, implementation and evaluation of future foam projects.

1995-05-01

31

The minimal series of N=1 and N=2 superconformal topological field theory  

International Nuclear Information System (INIS)

We obtain conformal invariant topological field theories with N = 2 supersymmetry by twisting Sevrin, Troost and Van Proeyen's SU(2) x SU(2) x U(1) extended N = 4 superconformal field theories. We expect that the number of physical states is finite although the original N = 4 theories have continuous spectra. It is shown that the number of physical states is actually finite when the central charge c < 6 in the corresponding N = 4 theories. The physical states inherit the structure of the chiral ring in N = 2 superconformal minimal series which is obtained by the reduction from N = 4 theories. We also show that the algebra contains the topological N = 4 superconformal algebra as subalgebra. Therefore a closed set of a finite number of physical states in the topological N = 1 superconformal algebra can also be obtained. (orig.).

1991-06-01

32

Matrix models as CFT: Genus expansion  

International Nuclear Information System (INIS)

We show how the formulation of the matrix models as conformal field theories on a Riemann surfaces can be used to compute the genus expansion of the observables. Here we consider the simplest example of the Hermitian matrix model, where the classical solution is described by a hyperelliptic Riemann surface. To each branch point of the Riemann surface we associate an operator which represents a twist field dressed by the modes of the twisted boson. The partition function of the matrix model is computed as a correlation function of such dressed twist fields. The perturbative construction of the dressing operators yields a set of Feynman rules for the genus expansion, which involve vertices, propagators and tadpoles. The vertices are universal, the propagators and the tadpoles depend on the Riemann surface. As a demonstration we evaluate the genus-two free energy using the Feynman rules.

2010-10-01

33

Integration of SPECT with CT to plan radiotherapy fields. n application to conformal irradiation for lung carcinoma  

International Nuclear Information System (INIS)

Single photon emission computed tomography (SPECT) of lung perfusions permits to map functioning lung parenchyma with higher sensitivity than CT. Delivering higher radiations doses it used to increase local control in lung carcinoma; this strategy is based on radiobiological and clinical studies. Lung parenchyma is a dose-limiting tissue in patients irradiated for lung cancer. Functional mapping based on SPECT and CT findings permits to design radiation beams such as to minimize irradiation of functioning lung.

1999-04-01

34

Computer-assisted rotation and multiple stationary irradiation technique  

International Nuclear Information System (INIS)

A computer-assisted rotation and stationary conformation radiotherapy system with overrunning multileaf collimators has been developed. This system can produce any shape of target volume, including a number of target areas outside the axis of the rotation, regardless of the location of the axis at 360"0 rotation irradiation. In addition, by changing the dose rate and deleting a partial region within a field, multiple stationary irradiation can produce more homogeneous target volumes - thus avoiding excessive irradiation to critical organs - than the rotation technique. (orig.).

35

The effects of applied magnetic fields on the {alpha}/{gamma} phase boundary in the Fe-Si system  

Energy Technology Data Exchange (ETDEWEB)

The CALPHAD (calculations of phase diagrams) method is used to examine the effects of applied magnetic fields on the {alpha}/{gamma} phase boundary in the Fe-Si system in the paramagnetic state. The reported susceptibility data for pure Fe is first re-evaluated. The contributions to the total Gibbs energy of the ferrite ({alpha}) and austenite ({gamma}) from the external fields are calculated based on the Curie-Weiss law and the re-evaluated susceptibility data. The Fe-Si phase diagram on the Fe-rich side as a function of applied field is calculated using the Thermo-Calc(TM) package. With increasing field strength, the {gamma} loop shrinks monotonically; that is, the {alpha}/{gamma}-Fe transition temperature increases while that for {gamma}/{delta}-Fe transition decreases, albeit more slowly. Finally, in conformance with the existing CALPHAD databank, Redlich-Kister polynomials are ...

2006-07-21

36

The structure of the W_#infinity# algebra  

International Nuclear Information System (INIS)

We prove rigorously that the structure constants of the leading (highest spin) linear terms in the commutation relations of the conformal chiral operator algebra W_#infinity# are identical to those of the Diff_0"+ R"2 algebra generated by area preserving diffeomorphisms of the plane. Moreover, all quadratic terms of the W_N algebra are found to be absent in the limit N#->##infinity#. In particular we show that W_#infinity# is a central extension of Diff_0"+ R"2 with non-trivial cocycles appearing only in the commutation relations of its Virasoro subalgebra. We also propose a representation of W_#infinity# in terms of a single scalar field in 2+1 dimensions and discuss its significance in the context of quantum field theory. (orig.).

1990-01-01

37

Scattering of discrete states in two-dimensional open string field theory  

Energy Technology Data Exchange (ETDEWEB)

This is the second in a series of papers devoted to open string field theory in two dimensions. In this paper we aim to clarify the origin and the role of discrete physical states in the theory. To this end, we study interactions of discrete states and generic tachyons. In particular, we discuss at length four point amplitudes. We show that the behavior of the correlation functions is governed by the number of generic tachyons involved and values of the kinematic invariants [ital s], [ital t], and [ital u]. The divergence of certain classes of correlators is shown to be the consequence of the fact that certain kinematic invariants are nonpositive integers in that case. Explicit examples are included. We check our results by the standard conformal technique.

1993-12-15

38

Design and field trial application of foam in production wells to improve conformance  

Energy Technology Data Exchange (ETDEWEB)

The experimental foam treatments conducted on two production wells, each in a different miscible flood pool, were described, including aspects of the laboratory work, numerical coning simulation, well selection process and foam placement strategy. One of the wells was injected with a foam-forming surfactant, as well as with a surface-generated preformed foam. Neither of these treatments had any effect on the performance of this well. In the other well, preformed foam treatment was successful in reducing gas-oil ratio, resulting in improved oil production over a 14-month period. Future foam injection projects are being planned, based on the experiences gained in this field experiment. 13 refs., 21 figs.

1997-02-01

39

The influence of electromagnetic field irradiated by high-voltage transmission lines on properties of cells.  

Science.gov (United States)

The influence of low-frequency electromagnetic field irradiating by high-voltage transmission lines on signal transduction of cell in spleen cells of the rates have been studied by molecular-biology techniques. The spleen cells are extracted from skilled rates, which are exposed in the electromagnetic field of high-voltage transmission lines with 4000 V/m and 0.09-0.1 G about 400 days. The quantity or level of phosphorylation of signal transducer and activator of transcription (STAT3) in JAK-STAT signal transduction pathway of spleen cells, which are stimulated and unstimulated by IL-2, respectively, are detected by the immunoblotting and immunobiochemistry. The results show that the expression of phospho-STAT3 in spleen cell stimulated by IL-2 differ not from that in the unstimulated cell. The former is significantly large than the latter. This shows that signal transduction of cell is affected by this electromagnetic ...

2005-01-01

40

The influence of tertiary structural restraints on conformational transitions in superhelical DNA.  

UK PubMed Central (United Kingdom)

This paper examines theoretically the effects that restraints on the tertiary structure of a superhelical DNA domain exert on the energetics of linking and the onset of conformational transitions. The...Full Text Available

1987-12-10

41

SQUID Eddy Current Technique Applying Conformable Eddy ...  

Science.gov (United States)

... Accession Number : ADD344580. Title : SQUID Eddy Current Technique Applying Conformable Eddy Current Probes,. Corporate Author : ...

42

Of McKay Correspondence, Non-linear Sigma-model and Conformal Field Theory  

CERN Document Server

The ubiquitous ADE classification has induced many proposals of often mysterious correspondences both in mathematics and physics. The mathematics side includes quiver theory and the McKay Correspondence which relates finite group representation theory to Lie algebras as well as crepant resolutions of Gorenstein singularities. On the physics side, we have the graph-theoretic classification of the modular invariants of WZW models, as well as the relation between the string theory nonlinear $\\sigma$-models and Landau-Ginzburg orbifolds. We here propose a unification scheme which naturally incorporates all these correspondences of the ADE type in two complex dimensions. An intricate web of inter-relations is constructed, providing a possible guideline to establish new directions of research or alternate pathways to the standing problems in higher dimensions.

2000-01-01

43

Experimental parameterization of an energy function for the simulation of unfolded proteins  

DEFF Research Database (Denmark)

The determination of conformational preferences in unfolded and disordered proteins is an important challenge in structural biology. We here describe an algorithm to optimize energy functions for the simulation of unfolded proteins. The procedure is based on the maximum likelihood principle and employs a fast and efficient gradient descent method to find the set of parameters of the energy function that best explain the experimental data. We first validate the method by using synthetic reference data, and subsequently apply the algorithms to data from nuclear magnetic resonance spin-labeling experiments on the Delta 131 Delta fragment of Staphylococcal nuclease. A significant strength of the procedure that we present is that it directly uses experimental data to optimize the energy parameters, without relying on the availability of high resolution structures. The procedure is fully general and can be applied to a range of experimental data and energy functions ...

2008-01-01

44

Conformity, political participation, and economic rewards: The case of Chinese private entrepreneurs  

British Library Electronic Table of Contents (United Kingdom)

Using institutional and resource dependence theories as the conceptual framework, this study identifies three forms of conformity?political, economic, and social?that can affect the level of private entrepreneurs? formal political participation in a transition economy. Data from a 2004 national-wide survey of 3,012 private firms in China show that political conformity (indicated by membership in the ruling party), economic conformity (amount of taxes paid), and social conformity (amount of charity donated) are each antecedents to private entrepreneurs? formal political participation. Moreover, political conformity negatively moderates the relationship between social conformity and private entrepreneurs? formal political participation?for party members, a lesser amount of charity is associa...

2011-01-01

45

Conformational analysis of ethyl azidoformate  

International Nuclear Information System (INIS)

A conformational analysis of ethyl azidoformate (EAF) has been carried out by the MINDO/3 quantum-chemical method. It has been shown that EAF exists in the form of two conformers differing with respect to rotation around the C-N bond. Complete optimization of the geometry has been carried out for both conformers. It has been found that the transoid conformation is planar and that the cisoid conformation is nonplanar. The height of the rotation barrier is 15.4 kcal/mole. The optimal geometry of the transition state has been calculated. It has been noted that a significant role in the mechanism of the conformational transition is played by the inversion of a nitrogen, which facilitates the transition. The results of the calculation have been confirmed by IR-spectroscopic data.

46

Unified description of bradyons and tachyons based on the dynamical SO(4,2) symmetry  

International Nuclear Information System (INIS)

Firstly the so called 'conformal relativity' in the 6-dimensional conformal space is formulated. In particular the concept of dilatational degree of freedom - scale - is introduced. The special conformal transformations are interpreted as the transformations connecting dilatationally moving frames (and objects). The ideas, similar to those by Kaluza and Klein, can be applied to the conformal space to obtain a unification of gravitation and electromagnetism. Lastly the conformal symmetry is extended to imaginary scales and to negative scales. Particles having imaginary scales are shown to be tachyons, whilst particles with negative scales correspond to antiparticles. (Auth.).

47

Architectural design criteria for f-block metal ion sequestering agents. 1998 annual progress report  

Energy Technology Data Exchange (ETDEWEB)

'The objective of this project is to provide a means to optimize ligand architecture for f-block metal recognition. The authors strategy builds on an innovative and successful molecular modeling approach in developing polyether ligand design criteria for the alkali and alkaline earth cations. The hypothesis underlying this proposal is that differences in metal ion binding with multidentate ligands bearing the same number and type of donor groups are primarily attributable to intramolecular steric factors. They propose quantifying these steric factors through the application of molecular mechanics models. The research involves close integration of theoretical and experimental chemistry. The experimental work entails synthesizing novel ligands and experimentally determining structures and binding constants for metal ion complexation by series of ligands in which architecture is systematically varied. The theoretical work entails using electronic structure calculations to ...

1998-12-31

48

String Junctions and Holographic Interfaces  

CERN Document Server

In this paper we study half-BPS type IIB supergravity solutions with multiple $AdS_3\\times S^3\\times M_4$ asymptotic regions, where $M_4$ is either $T^4$ or $K_3$. These solutions were first constructed in [1] and have geometries given by the warped product of $AdS_2 \\times S^2 \\times M_4 $ over $\\Sigma$, where $\\Sigma$ is a Riemann surface. We show that the holographic boundary has the structure of a star graph, i.e. $n$ half-lines joined at a point. The attractor mechanism and the relation of the solutions to junctions of self-dual strings in six-dimensional supergravity are discussed. The solutions of [1] are constructed introducing two meromorphic and two harmonic functions defined on $\\Sigma$. We focus our analysis on solutions corresponding to junctions of three different conformal field theories and show that the conditions for having a solution charged only under Ramond-Ramond three-form fields reduce to ...

2010-01-01

49

Intensity-Modulated Radiation Therapy with Noncoplanar Beams for Treatment of Prostate Cancer in Patients with Bilateral Hip Prosthesis-A Case Study  

International Nuclear Information System (INIS)

Megavoltage photon intensity-modulated radiation therapy (IMRT) is typically used in the treatment of prostate cancer at our institution. Approximately 1% to 2% of patients with prostate cancer have hip prostheses. The presence of the prosthesis usually complicates the planning process because of dose perturbation around the prosthesis, radiation attenuation through the prosthesis, and the introduction of computed tomography artifacts in the planning volume. In addition, hip prostheses are typically made of materials of high atomic number, which add uncertainty to the dosimetry of the prostate and critical organs in the planning volume. When the prosthesis is bilateral, treatment planning is further complicated because only a limited number of beam angles can be used to avoid the prostheses. In this case study, we will report the observed advantages of using noncoplanar beams in the delivery of IMRT to a prostate cancer patient with bilateral hip prostheses. The treatment was planned ...

2010-01-01

50

Molecular conformation, receptor binding, and hormone action of natural and synthetic estrogens and antiestrogens.  

UK PubMed Central (United Kingdom)

The X-ray crystallographic structural determinations of synthetic estrogens and antiestrogens provide reliable information on the global minimum energy conformation of these molecules or a local minimum...Full Text Available

1985-09-01

51

Conformational stability of alternating d (CG) oligomers in high salt solution.  

UK PubMed Central (United Kingdom)

The conformation of d (CG)n oligomers with n = 2,3 has been studied in aqueous solution in the presence of high salt concentration. A minimum n value of three is necessary to obtain a left-handed Z-helix....Full Text Available

1981-05-11

52

A model for the single stranded random coil form of polydeoxyadenylic acid from minimum energy conformations of the dimeric subunit.  

UK PubMed Central (United Kingdom)

The minimum energy conformations of dApdA have been examined for their suitability as buildings blocks of the single stranded coil form of polynucleotides. Calculations of the characteristic ratio C...Full Text Available

1978-09-01

53

Can intensity-modulated radiation therapy of the paraaortic region overcome the problems of critical organ tolerance?  

International Nuclear Information System (INIS)

Background and purpose: the recent RTOG guidelines for future clinical developments in gynecologic malignancies included the investigation of dose escalation in the paraaortic (PO) region which is, however, very difficult to target due to the presence of critical organs such as kidneys, liver, spinal cord, and digestive structures. The aim of this study was to investigate intensity-modulated radiotherapy's (IMRT) possibilities of either increasing, in a safe way, the dose to 50-60 Gy in case of macroscopic disease or decreasing the dose to organs at risk (OR) when treatment is given in an adjuvant setting. Material and methods: the dosimetric charts of 14 patients irradiated to the PO region at the department of radiation oncology, university hospital of Liege, Belgium, in 2000 were analyzed in order to compare six-field conformal external-beam radio-therapy (CEBR) and five-beam IMRT approaches. Both CEBR and IMRT investigations were planned to ...

2005-03-01

54

The influence of intramolecular H-bond on chromatographic behavior of phenylalkylamines  

British Library Electronic Table of Contents (United Kingdom)

The thermodynamic characteristics of adsorption on the surface of graphitized thermal carbon black at 300 K were determined by the molecular statistical method for three phenylalklylamines. The influence of the intramolecular H-bond on the conformation of the molecules compared with structurally related n-alkyl-benzenes was considered. It was shown that the conformations of the molecules could influence chromatographic retention. Conformational isomers stabilized by intramolecular H-bonds were found to retain their structure in adsorption on graphitized thermal carbon black.

2009-01-01

55

The influence of intramolecular H-bond on chromatographic behavior of phenylalkylamines  

Science.gov (United States)

The thermodynamic characteristics of adsorption on the surface of graphitized thermal carbon black at 300 K were determined by the molecular statistical method for three phenylalklylamines. The influence of the intramolecular H-bond on the conformation of the molecules compared with structurally related n-alkyl-benzenes was considered. It was shown that the conformations of the molecules could influence chromatographic retention. Conformational isomers stabilized by intramolecular H-bonds were found to retain their structure in adsorption on graphitized thermal carbon black.

2009-04-01

56

Non-uniqueness in conformal formulations of the Einstein constraints  

CERN Document Server

Standard methods in non-linear analysis are used to show that there exists a parabolic branching of solutions of the Lichnerowicz-York equation with an unscaled source. We also apply these methods to the extended conformal thin sandwich formulation and show that if the linearised system develops a kernel solution for sufficiently large initial data then we obtain parabolic solution curves for the conformal factor, lapse and shift identical to those found numerically by Pfeiffer and York. The implications of these results for constrained evolutions are discussed.

2006-01-01

57

Search for extended conformal algebra  

International Nuclear Information System (INIS)

The authors search for the extended conformal algebra with two spin-s (s:integer) and one spin-1 generators. This search is inspired by the existence of chiral algebra in the Gaussian model for rational radius. For odd s, the conformal properties of the three-point functions imply that a general fusion rule can be reduced to those of the Gaussian model. For arbitrary even s, these conditions are weaker. In particular, for s = 2 the authors show that the chiral algebra of the Gaussian model is the unique extended conformal algebra with the value of the central charge fixed to be c = 1. It is also shown that the conformal generator is necessarily a bilinear of the spin-1 generator just as the Gaussian model. The authors conjecture that this remains true for arbitrary value of s.

1990-08-01

58

Amplification of Inaccuracies of Initial Conditions in Cosmological Simulations  

Science.gov (United States)

Cosmological N-body and hydrodynamic simulations start with a realization of a random density fluctuation field representing a cosmological model at an early epoch. The density field is often replaced by a set of particles whose positions and velocities are set to conform to the desired density field. Each particle represents a cloud of huge number of real particles. Positions and velocities of particles are subsequently integrated by various numerical codes. We have simulated a set of collisionless collapses of Gaussian density peaks by using the PM and P(3) M codes. We find that in cosmological simulations the physics at scales below the mean particle separation(MPS) is dominated by inaccuracies in describing the initial density field, and cannot be studied even by the high force-resolution codes. Since density fluctuations are ill-defined at scales smaller than MPS, it is ...

1997-01-01

59

Water uptake and exchange kinetics of polyelectrolyte films: a neutron reflectometry study  

Energy Technology Data Exchange (ETDEWEB)

The sequential layer-by-layer adsorption of polyanions and polycations to build polyelectrolyte multilayers has triggered enormous interest in their potential uses in a wide range of fields, from photonic to pharmaceutical applications. We show that the conformation of the solvent swollen films - prior to drying - is determined by the initial adsorption conditions, but can be altered ex-situ by exposure to a liquid phase of very high ionic strength. Recently it has been observed that the swelling depends on the charge of the outermost layer. In the PAH/PSS system we saw that assemblies with PSS as the outermost layer swell more than those with PAH outside. A neutron reflectivity study of this effect in addition indicated the existence of two kinds of water, bound with different strength within the films. Beside an unexpected two-step kinetics of swelling, the reflectivity curves of the layers against vacuum before and after re-hydration in ...

2007-07-01

60

TENT - a CORBA based component architecture for MPI-parallel CFD simulation systems and their supporting tools  

Energy Technology Data Exchange (ETDEWEB)

This paper describes TENT, a system designed for integrating the various tools and parts of a CFD simulation system (CFD - Computational Fluid Dynamics) and the simulation code itself in one interactive simulation environment. Initially the system was intended to be a TEstbed for Numerical Turbine simulation but it turned out that the approach was general enough to be suitable for more complex simulation tasks in the field of aircraft simulation. The paper will give a brief description of a CFD simulation system and its component interactions, which are the basis for describing the Component Architecture based on CORBA. This includes the control architecture using an event model and data flow considerations. Because most CFD codes use parallelization techniques based on Message Passing, a so called MIMD Object Abstraction is described in order to abstract the parallel computation threads to a single CORBA conform instance. The main goal for ...

1998-07-01

61

Localized tachyons in C{sup 3}/Z{sub N}  

Energy Technology Data Exchange (ETDEWEB)

We study the condensation of localized closed string tachyons in C{sup 3}/Z{sub N} non-supersymmetric noncompact orbifold singularities via renormalization group flows that preserve supersymmetry in the worldsheet conformal field theory and their interrelations with the toric geometry of these orbifolds. We show that for worldsheet supersymmetric tachyons, the endpoint of tachyon condensation generically includes 'geometric' terminal singularities (orbifolds that do not have any marginal or relevant Kahler blowup modes) as well as singularities in co-dimension two. Some of the various possible distinct geometric resolutions are related by flip transitions. For Type II theories, we show that the residual singularities that arise under tachyon condensation in various classes of Type II theories also admit a Type II GSO projection. We further show that Type II orbifolds entirely devoid of marginal or relevant blowup modes (Kahler ...

2004-08-01

62

KINEMATICS AT THE EDGE OF THE GALACTIC BULGE: EVIDENCE FOR CYLINDRICAL ROTATION  

International Nuclear Information System (INIS)

We present new results from BRAVA, a large-scale radial velocity survey of the Galactic bulge, using M giant stars selected from the Two Micron All Sky Survey catalog as targets for the Cerro Tololo Inter-American Observatory 4 m Hydra multi-object spectrograph. The purpose of this survey is to construct a new generation of self-consistent bar models that conform to these observations. We report the dynamics for fields at the edge of the Galactic bulge at latitudes b = -8 deg. and compare to the dynamics at b = -4 deg. We find that the rotation curve V(r) is the same at b = -8 deg. as at b = -4 deg. That is, the Galactic boxy bulge rotates cylindrically, as do boxy bulges of other galaxies. The summed line-of-sight velocity distribution at b = -8 deg. is Gaussian, and the binned longitude-velocity plot shows no evidence for either a (disk) population with cold dynamics or for a (classical bulge) population with hot dynamics. The observed ...

2009-09-10

63

Diffractive deep inelastic scattering in an AdS/CFT inspired model: A phenomenological study  

International Nuclear Information System (INIS)

The analytical treatment of the nonperturbative QCD dynamics is one of the main open questions of the strong interactions. Currently, it is only possible to get some qualitative information about this regime considering other QCD-like theories, as, for example, the N=4 super Yang-Mills theory, where one can perform calculations in the nonperturbative limit of large 't Hooft coupling using the anti-de Sitter space/conformal field theory (AdS/CFT). Recently, the high energy scattering amplitude was calculated in the AdS/CFT approach, applied to deep-inelastic scattering and confronted with the F_2 HERA data. In this work we extend the nonperturbative AdS/CFT inspired model for diffractive processes and compare its predictions with a perturbative approach based on the Balitsky-Kovchegov equation. We demonstrate that the AdS/CFT inspired model is not able to describe the current F_2"D"("3") HERA data and predicts a similar behavior to that from the ...

2010-05-01

64

All-atom molecular dynamics simulations using orientational constraints from anisotropic NMR samples  

Science.gov (United States)

Orientational constraints obtained from solid state NMR experiments on anisotropic samples are used here in molecular dynamics (MD) simulations for determining the structure and dynamics of several different membrane-bound molecules. The new MD technique is based on the inclusion of orientation dependent pseudo-forces in the COSMOS-NMR force field. These forces drive molecular rotations and re-orientations in the simulation, such that the motional time-averages of the tensorial NMR properties approach the experimentally measured parameters. The orientational-constraint-driven MD simulations are universally applicable to all NMR interaction tensors, such as chemical shifts, dipolar couplings and quadrupolar interactions. The strategy does not depend on the initial choice of coordinates, and is in principle suitable for any flexible molecule. To test the method on three systems of increasing complexity, we used as constraints some deuterium quadrupolar couplings from ...

2007-03-03

65

All-atom molecular dynamics simulations using orientational constraints from anisotropic NMR samples  

Energy Technology Data Exchange (ETDEWEB)

Orientational constraints obtained from solid state NMR experiments on anisotropic samples are used here in molecular dynamics (MD) simulations for determining the structure and dynamics of several different membrane-bound molecules. The new MD technique is based on the inclusion of orientation dependent pseudo-forces in the COSMOS-NMR force field. These forces drive molecular rotations and re-orientations in the simulation, such that the motional time-averages of the tensorial NMR properties approach the experimentally measured parameters. The orientational-constraint-driven MD simulations are universally applicable to all NMR interaction tensors, such as chemical shifts, dipolar couplings and quadrupolar interactions. The strategy does not depend on the initial choice of coordinates, and is in principle suitable for any flexible molecule. To test the method on three systems of increasing complexity, we used as constraints some deuterium quadrupolar couplings from ...

2007-05-15

66

All-atom molecular dynamics simulations using orientational constraints from anisotropic NMR samples  

International Nuclear Information System (INIS)

Orientational constraints obtained from solid state NMR experiments on anisotropic samples are used here in molecular dynamics (MD) simulations for determining the structure and dynamics of several different membrane-bound molecules. The new MD technique is based on the inclusion of orientation dependent pseudo-forces in the COSMOS-NMR force field. These forces drive molecular rotations and re-orientations in the simulation, such that the motional time-averages of the tensorial NMR properties approach the experimentally measured parameters. The orientational-constraint-driven MD simulations are universally applicable to all NMR interaction tensors, such as chemical shifts, dipolar couplings and quadrupolar interactions. The strategy does not depend on the initial choice of coordinates, and is in principle suitable for any flexible molecule. To test the method on three systems of increasing complexity, we used as constraints some deuterium quadrupolar couplings from ...

2007-05-01

67

Accelerated aging tests of liners for uranium mill tailings disposal  

Energy Technology Data Exchange (ETDEWEB)

This document describes the results of accelerated aging tests to determine the long-term effectiveness of selected impoundment liner materials in a uranium mill tailings environment. The study was sponsored by the US Department of Energy under the Uranium Mill Tailings Remedial Action Project. The study was designed to evaluate the need for, and the performance of, several candidate liners for isolating mill tailings leachate in conformance with proposed Environmental Protection Agency and Nuclear Regulatory Commission requirements. The liners were subjected to conditions known to accelerate the degradation mechanisms of the various liners. Also, a test environment was maintained that modeled the expected conditions at a mill tailings impoundment, including ground subsidence and the weight loading of tailings on the liners. A comparison of installation costs was also performed for the candidate liners. The laboratory testing and cost information prompted the ...

1981-11-01

68

Modified-VSIMM algorithm with an application to the naval fire control technology  

British Library Electronic Table of Contents (United Kingdom)

A modified variable structure interacting multiple model (M-VSIMM) estimator for complex hybrid maneuver target tracking is presented. The M-VSIMM could potentially be applied to fire control systems (FCS) used on warships. Target model groups were designed using 3D dimensional dynamic target models. Optimal model group selection logic was proposed, contrary to the activation and termination logic in the original VSIMM. The system will respond faster with optimal model group selection logic. After performing simulations, the tracking performances of the Kalman, ?-?(-?), VDIE, IMM and M-VSIMM filters were compared under various maneuvering conditions.

2011-01-01

69

Direct aperture optimization of breast IMRT and the dosimetric impact of respiration motion  

International Nuclear Information System (INIS)

We have studied the application of direct aperture optimization (DAO) as an inverse planning tool for breast IMRT. Additionally, we have analysed the impact of respiratory motion on the quality of the delivered dose distribution. From this analysis, we have developed guidelines for balancing the desire for a high-quality optimized plan with the need to create a plan that will not degrade significantly in the presence of respiratory motion. For a DAO optimized breast IMRT plan, the tangential fields incorporate a flash field to cover the range of respiratory motion. The inverse planning algorithm then optimizes the shapes and weights of additional segments that are delivered in combination with the open fields. IMRT plans were generated using DAO with the relative weights of the open segments varied from 0% to 95%. To assess the impact of breathing motion, the dose distribution for the optimized IMRT plan was recalculated ...

2006-10-21

70

Reduction of RF-sheaths potentials by compensation or suppression of parallel RF currents on ICRF antennas  

International Nuclear Information System (INIS)

Radio frequency (RF) sheaths are suspected of limiting the performance of present-day ion cyclotron range of frequencies (ICRFs) antennas over long pulses and should be minimized in future fusion devices. Within the simplest models, RF-sheath effects are quantified by the integral VRF = ? E|| ? dl where the parallel RF field E|| is linked with the slow wave. On 'long open field lines' with large toroidal extension on both sides of the antenna it was shown that VRF is excited by parallel RF currents j|| flowing on the antenna structure. In this paper, the validity of this simple sheath theory is tested experimentally on the Tore Supra (TS) ITER-like antenna prototype (ILP), together with antenna simulation and post-processing codes developed to compute VRF. The predicted poloidal localization of high-|VRF| zones is confronted to that inferred from experimental data analysis. Surface temperature distribution on ILP front face, as well as ...

2010-02-01

71

Cosmologies with quasiregular singularities. II. Stability considerations  

Energy Technology Data Exchange (ETDEWEB)

The stability properties of a class of spacetimes with quasiregular singularities is discussed. Quasiregular singularities are the end points of incomplete, inextendible geodesics at which the Riemann tensor and its derivatives remain at least bounded in all parallel-propagated orthonormal (PPON) frames; observers approaching such a singularity would find that their world lines come to an end in a finite proper time. The Taub-NUT (Newman-Unti-Tamburino)-type cosmologies investigated are R/sup 1/ x T/sup 3/ and R/sup 3/ x S/sup 1/ flat Kasner spacetimes, the two-parameter family of spatially homogeneous but anisotropic Bianchi type-IX Taub-NUT spacetimes, and an infinite-dimensional family of Einstein-Rosen-Gowdy spacetimes studied by Moncrief. The behavior of matter near the quasiregular singularity in each of these spacetimes is explored through an examination of the behavior of the stress-energy tensors and scalars for conformally coupled and minimally coupled, ...

1985-03-15

72

Cosmologies with quasiregular singularities. II. Stability considerations  

International Nuclear Information System (INIS)

The stability properties of a class of spacetimes with quasiregular singularities is discussed. Quasiregular singularities are the end points of incomplete, inextendible geodesics at which the Riemann tensor and its derivatives remain at least bounded in all parallel-propagated orthonormal (PPON) frames; observers approaching such a singularity would find that their world lines come to an end in a finite proper time. The Taub-NUT (Newman-Unti-Tamburino)-type cosmologies investigated are R"1 x T"3 and R"3 x S"1 flat Kasner spacetimes, the two-parameter family of spatially homogeneous but anisotropic Bianchi type-IX Taub-NUT spacetimes, and an infinite-dimensional family of Einstein-Rosen-Gowdy spacetimes studied by Moncrief. The behavior of matter near the quasiregular singularity in each of these spacetimes is explored through an examination of the behavior of the stress-energy tensors and scalars for conformally coupled and minimally coupled, massive and massless ...

73

Treatment of prostatic cancer using daily intermittent multiportal therapy (DIMT) technique  

Energy Technology Data Exchange (ETDEWEB)

In the treatment of prostatic cancer using a newly proposed intermittent multiportal therapy (DIMT), acute reactions, change in tumor marker levels, and complications more than 6 months after treatment were evaluated. From June 1989 to September 1990, 26 patients with prostatic cancer (stage A2, 3 patients; B, 9; C, 2; D, 10; recurrence, 2) were treated. Fifteen patients were followed up for more than one year, with a mean period of 11.6 months. The treatment schedule is 52.5 Gy in 16 fractions in 4 weeks for radical treatment, and 30.0 Gy in 8 fractions in 2 weeks for palliative treatment. The 360 degree rotation about the patient was divided into 16 fractions, and 2 opposing fractions were used in one day as parallel opposed portals to treat the target volume. The fractions were serially treated one per day, so that 8 treatment days produced a total dose of distribution similar to that for conventional conformational therapy. The size of the irradiation ...

1992-06-01

74

Can intensity-modulated radiation therapy of the paraaortic region overcome the problems of critical organ tolerance?  

Energy Technology Data Exchange (ETDEWEB)

Background and purpose: the recent RTOG guidelines for future clinical developments in gynecologic malignancies included the investigation of dose escalation in the paraaortic (PO) region which is, however, very difficult to target due to the presence of critical organs such as kidneys, liver, spinal cord, and digestive structures. The aim of this study was to investigate intensity-modulated radiotherapy's (IMRT) possibilities of either increasing, in a safe way, the dose to 50-60 Gy in case of macroscopic disease or decreasing the dose to organs at risk (OR) when treatment is given in an adjuvant setting. Material and methods: the dosimetric charts of 14 patients irradiated to the PO region at the department of radiation oncology, university hospital of Liege, Belgium, in 2000 were analyzed in order to compare six-field conformal external-beam radio-therapy (CEBR) and five-beam IMRT approaches. Both CEBR and IMRT investigations were ...

2005-03-01

75

Conformal radiation therapy: technical requirements and clinical applications  

International Nuclear Information System (INIS)

Conformal radiation therapy represents a considerable and attractive challenge in oncology. Its aim is mainly to improve local control by increasing the dose with an acceptable rate of complications. This work overviews the world literature on this subject. The technical and theoretical requirements are highlighted. These requirements include a precise definition of the target volume by digital imaging (essentially CT scan), but also clear view of the target volume and the organs at risk, a specific collimation of the beam, 3-D dose calculations, optimization procedures, and a rigid immobilization of the patient with verification of his position. Moreover, the clinical applications of conformal radiation therapy are reviewed and discussed. (authors). 80 refs., 1 tab.

1995-01-01

76

Tensors, spinors, and functions on the unit sphere  

International Nuclear Information System (INIS)

A representation of tensors and spinors at a point of space-time as spin and conformally weighted functions on the unit sphere is derived. Methods for performing algebraic operations on tensors and spinors in this representation are discussed. (author).

77

SAXS studies on added-salt species dependence of conformation of fully-charged poly(L-glutamate) in aqueous solutions  

Energy Technology Data Exchange (ETDEWEB)

The effect of counter-ion species on the local conformation of fully-charged poly(L-glutamate) in added-salt aqueous solutions were studied by small-angle X-ray scattering(SAXS). In the case of presence of monovalent counter-ion, the scattering behaviour could be explained by taking into consideration the excluded volume effect and intermolecular-interface interaction on the scattering function of wormlike chain. On the other hand, since SAXS profile of the solution in the presence of divalent counter-ion well fitted to the scattering function of dendrimer, it suggested that the conformation of polymer chain in such solution would be more compact conformation than that of presence of monovalent ion.

2010-10-01

78

Metallic stent and stereotactic conformal radiotherapy for hilar cholangiocarcinoma  

International Nuclear Information System (INIS)

Objective: To evaluate the effect of metallic stent combined with stereotactic conformal radiotherapy (SCRT) for hilar cholangiocarcinoma. Methods: Fifty-four patients with hilar cholangiocarcinoma were analyzed, including 31 treated with stent plus stereotactic conformal radiotherapy (combined group) and 23 with metallic stent alone (control group). Results: The mean survival time of combined group was 11.1 #+-# 4.6 months, compared with 5.1 #+-# 2.8 months of the control group, giving a significant difference between the two groups (P<0.01). Conclusion: The combination of metallic stent and stereotactic conformal radiotherapy is more effective than metallic stent alone for unresectable hilar cholangiocarcinoma. (authors)

2005-01-01

79

Heat shock proteins as emerging therapeutic targets  

UK PubMed Central (United Kingdom)

Chaperones (stress proteins) are essential proteins to help the formation and maintenance of the proper conformation of other proteins and to promote cell survival after a large variety of environmental...Full Text Available

2005-11-01

80

Monte Carlo simulation of electron cones used in electron beam therapy  

International Nuclear Information System (INIS)

A Siemens Mevatron KV2 accelerator installed at the Royal Adelaide Hospital employs cylindrical solid-walled electron cones for some electron collimation. The cones being used at present result in treatment fields that do not always conform with the International Electrotechnical Commission (IEC) Standards (particularly at high energies). The aim of this project was to simulate the existing cones using Monte Carlo methods in order to evaluate potential cone modifications required to overcome the field irregularities. Simulations were performed using the EGS4 (Electron Gamma Shower version 4, distribution II) Monte Carlo code installed on a DEC Alpha workstation at the University of South Australia. To rigorously simulate the existing electron cones it was necessary to also simulate various components within the treatment head of the linear accelerator. Results of simulations for existing cones were found to be consistent ...

1998-09-01

81

Tensor network states and geometry  

CERN Document Server

Tensor network states are used to approximate ground states of local Hamiltonians on a lattice in D spatial dimensions. Different types of tensor network states can be seen to generate different geometries. Matrix product states (MPS) in D=1 dimensions, as well as projected entangled pair states (PEPS) in D>1 dimensions, reproduce the D-dimensional physical geometry of the lattice model; in contrast, the multi-scale entanglement renormalization ansatz (MERA) generates a (D+1)-dimensional holographic geometry. Here we focus on homogeneous tensor networks, where all the tensors in the network are copies of the same tensor, and argue that certain structural properties of the resulting many-body states are preconditioned by the geometry of the tensor network and are therefore largely independent of the choice of variational parameters. Indeed, the asymptotic decay of correlations in homogeneous MPS and MERA for D=1 systems is seen to be determined by the structure ...

2011-01-01

82

Reversible conformational change in herpes simplex virus glycoprotein B with fusion-from-without activity is triggered by mildly acidic pH  

UK PubMed Central (United Kingdom)

BackgroundThe pre-fusion form of the herpes simplex virus (HSV) fusion protein gB undergoes pH-triggered conformational change in vitro and during viral entry (Dollery...Full Text Available

83

Conformational transitions of alternating purine-pyrimidine DNAs in perchlorate ethanol solutions.  

UK PubMed Central (United Kingdom)

Conformational transitions of poly(dA-dC).poly(dG-dT), poly(dA-dT).poly(dA-dT), and other alternating purine-pyrimidine DNAs were studied in aqueous ethanol solutions containing molar concentrations...Full Text Available

1995-11-01

84

Comparing two strategies of dynamic intensity modulated radiation therapy (dIMRT) with 3-dimensional conformal radiation therapy (3DCRT) in the hypofractionated treatment of high-risk prostate cancer  

UK PubMed Central (United Kingdom)

BackgroundTo compare two strategies of dynamic intensity modulated radiation therapy (dIMRT) with 3-dimensional conformal radiation therapy (3DCRT) in the setting of hypofractionated...Full Text Available

85

Comparative study of convolution, superposition, and fast superposition algorithms in conventional radiotherapy, three-dimensional conformal radiotherapy, and intensity modulated radiotherapy techniques for various sites, done on CMS XIO planning system  

UK PubMed Central (United Kingdom)

The aim of this study is to compare the dosimetry results that are obtained by using Convolution, Superposition and Fast Superposition algorithms in Conventional Radiotherapy, Three-Dimensional Conformal...Full Text Available

2009-01-01

86

A new unified approach to bradyons and tachyons by conformal transformations  

International Nuclear Information System (INIS)

By using linearized conformal transformations in six dimensions, a new unified approach to bradyons (v"2< c"2) and tachyons (v"2>c"2) is suggested, the essential tool being (real and imaginary) dilatations. The usual ''Generalized Lorentz transformations'' are got, In six dimensions the quadrate form is always positive, both for bradyons and for tachyons.

87

C-106 tank process ventilation test  

Energy Technology Data Exchange (ETDEWEB)

Project W-320 Acceptance Test Report for tank 241-C-106, 296-C-006 Ventilation System Acceptance Test Procedure (ATP) HNF-SD-W320-012, C-106 Tank Process Ventilation Test, was an in depth test of the 296-C-006 ventilation system and ventilation support systems required to perform the sluicing of tank C-106. Systems involved included electrical, instrumentation, chiller and HVAC. Tests began at component level, moved to loop level, up to system level and finally to an integrated systems level test. One criteria was to perform the test with the least amount of risk from a radioactive contamination potential stand point. To accomplish this a temporary configuration was designed that would simulate operation of the systems, without being connected directly to the waste tank air space. This was done by blanking off ducting to the tank and connecting temporary ducting and an inlet air filter and housing to the recirculation system. This configuration would eventually become the possible ...

1998-07-20

88

Virasoro algebra action on integrable hierarchies and Virasoro contraints in matrix models  

International Nuclear Information System (INIS)

The action of the Virasoro algebra on integrable hierarchies of non-linear equations and on related objects ('Schroedinger' differential operators) is investigated. The method consists in pushing forward the Virasoro action to the wave function of a hierarchy, and then reconstructing its action on the dressing and Lax operators. This formulation allows one to observe a number of suggestive similarities between the structures involved in the description of the Virasoro algebra on the hierarchies and the structure of conformal field theory on the world-sheet. This includes, in particular, an 'off-shell' hierarchy version of operator products and of the Cauchy kernel. In relation to matrix models, which have been observed to be effectively described by integrable hierarchies subjected to Virasoro constraints, I propose to define general Virasoro-constrained hierarchies also in terms of dressing operators, by certain equations which carry the ...

1991-12-01

89

Routine environmental audit of the Y-12 Plant, Oak Ridge, Tennessee  

Energy Technology Data Exchange (ETDEWEB)

This report documents the results of the routine environmental audit of the Oak Ridge Y-12 Plant (Y-12 Plant), Anderson County, Tennessee. During this audit, the activities conducted by the audit team included reviews of internal documents and reports from previous audits and assessments; interviews with U.S. Department of Energy (DOE), State of Tennessee regulatory, and contractor personnel; and inspections and observations of selected facilities and operations. The onsite portion of the audit was conducted August 22-September 2, 1994, by the DOE Office of Environmental Audit (EH-24), located within the Office of Environment, Safety and Health (EH). DOE 5482.1 B, {open_quotes}Environment, Safety, and Health Appraisal Program,{close_quotes} establishes the mission of EH-24 to provide comprehensive, independent oversight of DOE environmental programs on behalf of the Secretary of Energy. The ultimate goal of EH-24 is enhancement of environmental protection and minimization of risk to ...

1994-09-01

90

Mapping of the human cone transducin {alpha} subunit (GNAT2) gene to 1p13 and mutation analysis in patients with Stargardt`s disease  

Energy Technology Data Exchange (ETDEWEB)

Transducin {alpha} subunits are members of a large family of G-proteins and play an important role in phototransduction in rod and cone photoreceptors. We report the localization of the human cone {alpha} transducin (GNAT2) gene using fluorescence in situ hybridization (FISH) on chromosome 1 in band p13. The recent assignment of a gene for Stargardt`s disease to the same chromosomal region by linkage analysis prompted us to investigate the possible role of GNAT2 in the pathogenesis of this disease. Stargardt`s disease is characterized by degeneration in late childhood or early adulthood of the macula of the retina, a region rich in cones. We screened patients with Stargardt`s disease, with or without peripheral cone involvement as monitored by the full-field ERG, for mutations in this gene. We investigated 66 unrelated patients including 22 with peripheral cone dysfunction for mutations in the coding region of the GNAT2 gene using polymerase chain reaction-single ...

1994-09-01

91

AECL IMPELA electron beam industrial irradiators  

International Nuclear Information System (INIS)

A family of industrial irradiators is being developed by AECL to cover an electron-beam energy range from 5 to 18 MeV at beam powers between 20 and 250 kW. The IMPELA family of irradiators is designed for push button, reliable operation. The major irradiator components are modular, allowing for later upgrades to meet increased demands in either electron or X-ray mode. Interface between the control system, irradiator availability and dose quality assurance is in conformance with the most demanding specifications. The IMPELA irradiators use a klystron-driven, standing-wave, L-band accelerator structure with direct injection from a rugged, triode electron gun. Direct control of the accelerating field during the beam pulse ensures constant output beam energy, independent of beam power. The first member of the family, the IMPELA 10/50 (10 MeV, 50 kW), is in the final stages of assembly at Chalk River Nuclear Laboratories. The IMPELA 10/50 is ...

92

Real-time neutron scattering investigations of biological signal transduction dynamics  

Energy Technology Data Exchange (ETDEWEB)

During their catalytic cycle, proteins involved in biological signal transduction undergo unexpectedly large conformational changes, which are at the core of their biological functioning. Until now it has been extremely difficult to obtain experimental insight into the nature of these conformational changes. Mathematical modeling and time-resolved X-ray crystallography have resulted in probable routes along which these conformational changes may take place, but so far this fundamental biological phenomenon has hardly been tackled experimentally. Here, we report on an attempt to observe structural changes in Photoactive Yellow Protein with time-resolved small-angle neutron scattering using diffractometer D22 at the high-flux reactor of the Institut Laue-Langevin, Grenoble, France.

2005-07-01

93

Real-time neutron scattering investigations of biological signal transduction dynamics  

International Nuclear Information System (INIS)

During their catalytic cycle, proteins involved in biological signal transduction undergo unexpectedly large conformational changes, which are at the core of their biological functioning. Until now it has been extremely difficult to obtain experimental insight into the nature of these conformational changes. Mathematical modeling and time-resolved X-ray crystallography have resulted in probable routes along which these conformational changes may take place, but so far this fundamental biological phenomenon has hardly been tackled experimentally. Here, we report on an attempt to observe structural changes in Photoactive Yellow Protein with time-resolved small-angle neutron scattering using diffractometer D22 at the high-flux reactor of the Institut Laue-Langevin, Grenoble, France

2005-04-11

94

Newtonian photorealistic ray tracing of grating cloaks and correlation-function-based cloaking-quality assessment  

CERN Document Server

Grating cloaks are a variation of dielectric carpet (or ground- plane) cloaks. The latter were introduced by Li and Pendry. In contrast to the numerical work involved in the quasi-conformal carpet cloak, the refractive-index profile of a conformal grating cloak follows a closed and exact analytical form. We have previously mentioned that finite-size conformal grating cloaks may exhibit better cloaking than usual finite-size carpet cloaks. In this letter, we directly visualize their performance using photorealistic ray-tracing simulations. We employ a Newtonian approach that is advantageous compared to conventional ray tracing based on Snell's law. Furthermore, we quantify the achieved cloaking quality by computing the cross-correlations of rendered images. The cross-correlations for the grating cloak are much closer to 100% (i.e., ideal) than those for the Gaussian carpet cloak.

2010-01-01

95

Nearly Conformal QCD and AdS/CFT  

Energy Technology Data Exchange (ETDEWEB)

The AdS/CFT correspondence is a powerful tool to study the properties of conformal QCD at strong coupling in terms of a higher dimensional dual gravity theory. The power-law falloff of scattering amplitudes in the non-perturbative regime and calculable hadron spectra follow from holographic models dual to QCD with conformal behavior at short distances and confinement at large distances. String modes and fluctuations about the AdS background are identified with QCD degrees of freedom and orbital excitations at the AdS boundary limit. A description of form factors in space and time-like regions and the behavior of light-front wave functions can also be understood in terms of a dual gravity description in the interior of AdS.

2005-08-08

96

Constrained NBMPR analogue synthesis, pharmacophore mapping and 3D-QSAR modeling of equilibrative nucleoside transporter 1 (ENT1) inhibitory activity  

British Library Electronic Table of Contents (United Kingdom)

Conformationally constrained analogue synthesis was undertaken to aid in pharmacophore mapping and 3D-QSAR analysis of nitrobenzylmercaptopurine riboside (NBMPR) congeners as equilibriative nucleoside transporter 1 (ENT1) inhibitors. In our previous study [J. Med. Chem. 2003, 46, 831-837], novel regioisomeric nitro-1,2,3,4-tetrahydroisoquinoline conformationally constrained analogues of NBMPR were synthesized and evaluated as ENT1 ligands. 7-NO2-1,2,3,4-Tetrahydroisoquino-2-yl purine riboside was identified as the analogue with the nitro group in the best orientation at the NBMPR binding site of ENT1. In the present study, further conformational constraining was introduced by synthesizing 5prime-O,8-cyclo derivatives. The flow cytometrically determined binding affinities indicated that the...

2008-01-01

97

A new higher-spin algebra and the lone-star product  

International Nuclear Information System (INIS)

In two recent papers, we constructed a new N#->##infinity# limit of the W_N algebras, which we denote W_#infinity# having generators of conformal spins 2, 3, ..., with central terms for all spins. In this paper, we construct another new algebra, which we denote W_1_+_#infinity#, with generators of conformal spins, 1, 2, 3, ..., again with central terms for all spins. The requirement that the algebras be closed requires that one include the spin-1 generators in W_1_+_#infinity#, and prohibits their inclusion in W_#infinity#. Paralleling our analogous construction for W_#infinity#, we show that the new algebra can also be realised as the antisymmetric part of an associative 'lone-star' product, which also closes on the set of generators with conformal spins #>=#1. (orig.).

1990-06-01

98

Variation in the Definition of Clinical Target Volumes for Pelvic Nodal Conformal Radiation Therapy for Prostate Cancer  

UK PubMed Central (United Kingdom)

PurposeWe conducted a comparative study of Clinical Target Volume (CTV) definition of pelvic lymph nodes by multiple GU radiation oncologists looking at the levels...Full Text Available

2009-06-01

99

Two amyloid states of the prion protein display significantly different folding patterns  

UK PubMed Central (United Kingdom)

SummaryIt has been well established that a single amino acid sequence can give rise to several conformationally distinct amyloid states. The extent to which amyloid structures...Full Text Available

2010-07-23

100

Trypanosoma cruzi glycosomal glyceraldehyde-3-phosphate dehydrogenase does not conform to the 'hotspot' topogenic signal model.  

UK PubMed Central (United Kingdom)

The genes which encode glycosomal glyceraldehyde-phosphate dehydrogenase (gGAPDH) of Trypanosoma cruzi are arranged as a tandemly repeated pair on a single chromosome and are identical at the level...Full Text Available

1990-09-01

101

Role of Methoxypolyethylene Glycol on the Hydration, Activity, Conformation and Dynamic Properties of a Lipase in a Dry Film  

UK PubMed Central (United Kingdom)

A combined approach based on the use of ATR-FT/IR and steady-state fluorescence spectroscopy allowed to shed light on the effects of the additive methoxypolyethylene glycol (MePEG) on the hydration,...Full Text Available

2008-10-01

102

Prolonged signaling at the parathyroid hormone receptor by peptide ligands targeted to a specific receptor conformation  

UK PubMed Central (United Kingdom)

The parathyroid hormone receptor (PTHR) is a class B G protein-coupled receptor that plays critical roles in bone and mineral ion metabolism. Ligand binding to the PTHR involves interactions to both...Full Text Available

2008-10-28

103

Photophysics and optical switching in green fluorescent protein mutants  

UK PubMed Central (United Kingdom)

We demonstrate by using low-temperature high-resolution spectroscopy that red-shifted mutants of green fluorescent protein are photo-interconverted among three conformations and are, therefore, not...Full Text Available

2000-03-28

104

Non-contiguous regions of Z-DNA in a DNA dodecamer.  

UK PubMed Central (United Kingdom)

The conformation of the self-complimentary DNA dodecamer d(br5CGbr5CGAATTbr5CGbr5CG) has been investigated in a variety of salt and solvent conditions by one and two-dimensional 1H NMR. In low salt...Full Text Available

1989-10-11

105

Molecular dynamics of a ?B DNA element: base flipping via cross-strand intercalative stacking in a microsecond-scale simulation  

UK PubMed Central (United Kingdom)

The sequence-dependent structural variability and conformational dynamics of DNA play pivotal roles in many biological milieus, such as in the site-specific binding of transcription factors to target...Full Text Available

2008-09-01

106

Mitochondrial DNA Damage and Animal Longevity: Insights from Comparative Studies  

UK PubMed Central (United Kingdom)

Chemical reactions in living cells are under strict enzyme control and conform to a tightly regulated metabolic program. However, uncontrolled and potentially deleterious endogenous reactions occur,...Full Text Available

107

Laser-Assisted Single-Molecule Refolding (LASR)  

UK PubMed Central (United Kingdom)

To assemble into functional structures, biopolymers search for global minima through their folding potential energy surfaces to find the native conformation. However, this process can be hindered by...Full Text Available

2010-09-22

108

Effects of PKA phosphorylation on the conformation of the Na,K-ATPase regulatory protein FXYD1  

UK PubMed Central (United Kingdom)

FXYD1 (phospholemman) is a member of an evolutionarily conserved family of membrane proteins that regulate the function of the Na,K-ATPase enzyme complex in specific tissues and specific physiological...Full Text Available

2009-11-01

109

A frequency-based approach to locate common structure for 2D-3D intensity-based registration of setup images in prostate radiotherapy  

UK PubMed Central (United Kingdom)

In many radiotherapy clinics, geometric uncertainties in the delivery of 3D conformal radiation therapy and intensity modulated radiation therapy of the prostate are reduced by aligning the...Full Text Available

2007-07-01

110

Vibrational Circular Dichroism: A developing spectroscopic technique for peptide and protein conformational studies  

International Nuclear Information System (INIS)

Electronic circular dichroism (ECD) of the n-#pi# and #pi# -#pi# transitions of the amide groups in the ultraviolet has become an indispensable tool for qualitative characterization of proteins in solution. Since the existence of such a spectrum (that is, of natural optical activity) comes from the three dimensional interaction of the chromophores in the molecule, CD is exquisitely sensitive to molecular conformation. However, in proteins, the amide transitions available in the near UV are limited in number and are broads and overlapping. Interactions among them yield information about the polymeric backbone, but since such amide electronic excitation are relatively delocalized, the resulting

1996-11-01

111

Locked nucleic acid (LNA): High affinity targeting of RNA for diagnostics and therapeutics  

DEFF Research Database (Denmark)

Locked nucleic acid (LNA) is a nucleic acid analogue containing one or more LNA nucleotide monomers with a bicyclic furanose unit locked in an RNA mimicking sugar conformation. This conformational restriction results in unprecedented hybridization affinity towards complementary single stranded RNA and thus, makes LNA uniquely suited for mimicking RNA structures and sequence specific targeting of RNA in vitro or in vivo. The focus of this paper is on LNAantisense, LNA-modified siRNA (siLNA), and detection and analysis of microRNAs by LNA-modified oligonucleotide probes.

2005-01-01

112

Extended conformal algebras with N=1 supersymmetry  

Energy Technology Data Exchange (ETDEWEB)

Extended conformal algebras with supersymmetry (super-W/sub n/ algebra) is constructed and the algebras are shown to exist for special values of the central charge c. The super-W/sub n/ algebra containing currents of spin (5/2, 3) has a unitary representation (c=10/7) and a non-unitary one (c=-5/2), and the super-W/sub n/ algebra containing currents of spins (2, 5/2) has a non-unitary representation (c=-6/5).

1988-12-29

113

Distribution amplitudes of {sigma} and {lambda} and their electromagnetic form factors  

Energy Technology Data Exchange (ETDEWEB)

Based on QCD conformal partial wave expansion to leading order conformal spin accuracy, we present the light-cone distribution amplitudes (DAs) of {sigma} and {lambda} baryons up to twist 6. It is concluded that fourteen independent DAs are needed to describe the valence three-quark states of the baryons at small transverse separations. The nonperturbative parameters relevant to the DAs are determined within the framework of QCD sum rule method. With the obtained DAs, a simple investigation on the electromagnetic form factors of these baryons are given. The magnetic moments of the baryons are estimated by fitting the magnetic form factor with the dipole formula.

2009-04-15

114

Azidothymidine: crystal structure and possible functional role of the azido group  

Energy Technology Data Exchange (ETDEWEB)

The crystal and molecular structures of the anti-acquired immunodeficiency syndrome agent 3'-azido-3'-deoxythymidine (AZT) have been determined by x-ray diffraction. There are two crystallographically independent AZT molecules in the crystal asymmetric unit; they have similar conformation and differ primarily in the glycosyl torsion angle. Comparisons with a hydrated thymidylate structure indicate that the azido group does not significantly affect the gross conformational preference of the molecule. The comparisons also suggest possible functional roles for the azido group in enzyme binding.

1987-12-01

115

The quantum N-body problem with a minimal length  

CERN Document Server

The quantum $N$-body problem is studied in the context of nonrelativistic quantum mechanics with a one-dimensional deformed Heisenberg algebra of the form $[\\hat x,\\hat p]=i(1+\\beta \\hat p^2)$, leading to the existence of a minimal observable length $\\sqrt\\beta$. For a generic pairwise interaction potential, analytical formulas are obtained that allow to estimate the ground-state energy of the $N$-body system by finding the ground-state energy of a corresponding two-body problem. It is first shown that, in the harmonic oscillator case, the $\\beta$-dependent term grows faster with $N$ than the $\\beta$-independent one. Then, it is argued that such a behavior should be observed also with generic potentials and for $D$-dimensional systems. In consequence, quantum $N$-body bound states might be interesting places to look at nontrivial manifestations of a minimal length since, the more particles are present, the more the system deviates from standard quantum ...

2010-01-01

116

Skip-webs: Efficient distributed data structures for multi-dimensional data sets  

DEFF Research Database (Denmark)

We present a framework for designing efficient distributed data structures for multi-dimensional data. Our structures, which we call skip-webs, extend and improve previous randomized distributed data structures, including skipnets and skip graphs. Our framework applies to a general class of data querying scenarios, which include linear (one-dimensional) data, such as sorted sets, as well as multi-dimensional data, such as d-dimensional octrees and digital tries of character strings defined over a fixed alphabet. We show how to perform a query over such a set of n items spread among n hosts using O(log n / log log n) messages for one-dimensional data, or O(log n) messages for fixed-dimensional data, while using only O(log n) space per host. We also show how to make such structures dynamic so as to allow for insertions and deletions in O(log n) messages for quadtrees, octrees, and digital tries, and O(log n / log log n) messages for one-dimensional data. Finally, we ...

2005-01-01

117

Exploring the 2D to 3D dimensionality crossover in thin iron films  

Energy Technology Data Exchange (ETDEWEB)

The temperature dependence of the spontaneous magnetization of epitaxial iron films with a thickness ranging from d=20 to 200nm has been measured. The films are grown on GaAs (100) substrates which are covered by a 150nm thick silver (100) buffer layer. For three-dimensional BCC iron it was observed already in 1929 that saturation of the spontaneous magnetization for T->0 is perfectly described by a T{sup 2} power law. On the other hand, for thin two-dimensional (2D) iron films a T{sup 3/2} law has been established in many recent experimental investigations. In our iron films grown on diamagnetic silver, this dimensionality change occurs at a thickness between d=100 and 200nm. Comparison of the here-observed T{sup 3/2} coefficients with those on iron films grown on paramagnetic tungsten (110) shows that the 2D interactions are {approx}20 times larger in the films on tungsten. Recent results on Fe films which are grown directly on GaAs (100) confirm that the substrate has a very ...

2006-05-15

118

Concepts of radiotherapy treatment planning  

International Nuclear Information System (INIS)

Full text: Radiotherapy treatment planning (RTP) relies heavily on medical imaging. Until recently, the most important planning tool was the treatment simulator. The kilovoltage radiographic capabilities in a treatment simulator enabled the boundaries of treatment fields to be visualized with respect to bony anatomic landmarks. Perhaps the most important advance in treatment planning in recent years is the ability to visualize the passage of the beams with respect to a more accurate geometrical representation of the tumor and other soft tissue structures. This 'virtual simulation' uses a computer-based representation of a patient to determine the extent of the disease and the location of radiation sensitive normal tissue. Computer tomographic (CT) imaging produces a high-resolution three-dimensional representation of anatomy that can be correlated with other image sets such as magnetic resonance images (MRI) of function. Positron emission tomographic (PET) imaging ...

2000-12-01

119

Integration of SPECT with CT to plan radiotherapy fields. n application to conformal irradiation for lung carcinoma; Integrazione delle immagini della Tomografia Computerizzata con emissione di fotone singolo in un sistema commerciale per l'elaborazione dei piani di radioterapia. Applicazione all'irradiazione conformazionale del carcinoma polmonare  

Energy Technology Data Exchange (ETDEWEB)

Single photon emission computed tomography (SPECT) of lung perfusions permits to map functioning lung parenchyma with higher sensitivity than CT. Delivering higher radiations doses it used to increase local control in lung carcinoma; this strategy is based on radiobiological and clinical studies. Lung parenchyma is a dose-limiting tissue in patients irradiated for lung cancer. Functional mapping based on SPECT and CT findings permits to design radiation beams such as to minimize irradiation of functioning lung. [Italian] L'integrazione delle immagini diagnostiche aventi diverso contenuto informativo anatomico-funzionale puo' essere utilizzata nella radioterapia per migliorare le procedure diagnostiche e ottimizzare la geometria dell'irraggiamento. I sistemi per l'elaborazione di piani di radioterapia oggi in uso sono direttamente interfacciati con gli apparecchi di Tomografia Computerizzata (TC) e l'impiego di immagini provenienti da altre ...

1999-04-01

120

A multi-disciplinary study investigating radiotherapy in Ewing's sarcoma - a final report of POG 8346  

International Nuclear Information System (INIS)

Purpose: To determine if involved field radiation (IF) is equivalent to standard whole bone radiation (SF) in local tumor control; to establish patterns of failure following treatment; and to determine response, event free (EFS) and overall survival rates from multi-disciplinary therapy in Ewing's Sarcoma (ES). Materials and Methods: Between 1983 and 1988, 184 children with ES were enrolled onto POG 8346. 178 (97%) met eligibility criteria; 6 had non-ES pathology. Induction treatment of Cyclophosphamide/Adriamycin (C/A) x 12 weeks was followed by local treatment either surgery or radiation therapy (XRT) and C/A, Dactinomycin and Vincristine for 50 weeks. Resection was advised for patients with small primary tumors if accomplished without functional loss. 40 patients were randomized to receive SF, whole bone XRT to 39.6 Gy plus a 16.2 Gy boost (total 55.8 Gy) or IF to 55.8 Gy while 84 were assigned to IF XRT. Results: Of 179 eligible patients, 141 (79%) had ...

121

Synthesis, solid and solution studies of paraquat dichloride calixarene complexes. Molecular modelling  

International Nuclear Information System (INIS)

The interaction of the herbicide paraquat dichloride (P Q, substrate) with p-tert-butylcalix arenas (L, receptor) was investigated in both the solution and solid states. The isolated paraquat calixarene complexes were characterised by UV-visible, 1H NMR, ESI-Ms, Luminescence and IR spectroscopies and elemental analysis. The stoichiometry of complexes 1 and 2 was 1:1 (1 herbicide: 1 calixarene) and both revealed a biexponential luminescence decay with lifetimes depending on the size and the conformational particularity of the calixarenes. Molecular modelling suggested that both calixarenes interact with the herbicide through cation-? interaction. P Q in included in the p-tert butylcalix a rene cavity, a situation favoured by its pinched conformation in polar solvent while it is partially included in the p-tert butylcalix a rene cavity because of its in-out cone conformation. The theoretical results, in particular using Mopac ...

122

Studies of the involvement of metal ions with several medicinal agents  

Energy Technology Data Exchange (ETDEWEB)

NMR and CD studies indicate that Mg/sup 2 +/ and Ca/sup 2 +/ are able to change the conformation of tetracycline in DMSO solution. This may affect the in vivo effect of tetracycline. Using /sup 23/Na NMR, the formation constant of NaLAS (LAS represents the anion of lasalocid A) was found to be 80 M/sup -1/ which is much smaller than that in less polar solvents. Spin-lattice relaxation measurements were made to study the binding sites of Gd/sup 3 +/ on Las in ChCl/sub 3/-DMF mixed solvent system. No intermediate conformation (between cyclic and open-chain) was found. LAS was found to be a good second-sphere ligand to inert transition-metal amines. NMR studies suggest that LAS is in cyclic conformation when bound to these metal amines. A new method for the synthesis of spin-labeled anticancer Pt(II) complexes was developed. It is very simple and gives high yield of pure spin-labeled Pt(II) complexes.

1985-01-01

123

Positive energy representations of the conformal quantum algebra  

International Nuclear Information System (INIS)

The positive-energy unitary irreducible representations of the q-deformed conformal algebra #delta#C_q = U_q(su(2,2)) are obtained by appropriate deformation of the classical ones. When the deformation parameter q is N -th root of unity, all these unitary representations become finite-dimensional. For his case we discuss in some detail the massless representations, which are also irreducible representations of the q-deformed Poincare subalgebra of #delta#C_q. Generically, their dimensions are smaller than the corresponding finite-dimensional non-unitary representation of su(2,2), except when N = 2 modul h + 1, where h is the helicity of the representations. The latter cases include the fundamental representations with h = #+-#1/2. (author). 10 refs.

1985-05-22

124

Gravity Dual for a Model of Perception  

CERN Document Server

One of the salient features of human perception is its invariance under dilatation in addition to the Euclidean group, but its non-invariance under special conformal transformation. We investigate a holographic approach to the information processing in image discrimination with this feature. We claim that a strongly coupled analogue of the statistical model proposed by Bialek and Zee can be holographically realized in scale invariant but non-conformal Euclidean geometries. We identify the Bayesian probability distribution of our generalized Bialek-Zee model with the GKPW partition function of the dual gravitational system. We provide a concrete example of the geometric configuration based on a vector condensation model coupled with the Euclidean Einstein-Hilbert action. From the proposed geometry, we study sample correlation functions to compute the Bayesian probability distribution.

2010-01-01

125

Electron beam, ion beam, X-ray optical techniques for fabricating surface-acoustic-wave and thin-film optical devices  

International Nuclear Information System (INIS)

Most surface-acoustic-wave and thin-film optical devices are made by the planar fabrication process. The exposure of the pattern in the polymer film is the first and most crucial step in ensuring desired device geometry, dimensional control, and freedom from pattern distortion. The methods of exposing the polymer film include: optical projection, conventional contact printing, conformable photomask contact printing, holographic recording, scanning electron beam lithography, projection electron lithography, and x-ray lithography. In this paper scanning electron beam lithography, conformable photomask contact printing, holographic recording, and x-ray lithography are discussed. In the last section, ion beam etching of relief structures is discussed.

126

Biosorption of uranium (VI) by immobilized Aspergillus fumigatus beads  

Energy Technology Data Exchange (ETDEWEB)

Biosorption of uranium (VI) ions by immobilized Aspergillus fumigatus beads was investigated in a batch system. The influences of solution pH, biosorbent dose, U (VI) concentration, and contact time on U (VI) biosorption were studied. The results indicated that the adsorption capacity was strongly affected by the solution pH, the biosorbent dose and initial U (VI) concentration. Optimum biosorption was observed at pH 5.0, biosrobent dose (w/v) 2.5%, initial U (VI) concentration 60 mg L{sup -1}. Biosorption equilibrium was established in 120 min. The adsorption process conformed to the Freunlich and Temkin isothermal adsorption models. The dynamic adsorption model conformed to pseudo-second order model.

2010-06-15

127

Biopolymer system for permeability modification in porous media  

Energy Technology Data Exchange (ETDEWEB)

New technologies are needed to reduce the current high rate of well abandonment. Improved sweep efficiency, reservoir conformance, and permeability modification can have a significant impact on oil recovery processes. Microorganisms can be used to selectively plug high-permeability zones to improve sweep efficiency and impart conformance control. Studies of a promising microbial system for polymer production were conducted to evaluate reservoir conditions in which this system would be effective. Factors which can affect microbial growth and polymer production include salinity, pH, temperature, divalent ions, presence of residual oil, and rock matrix. Flask tests and coreflooding experiments were conducted to optimize and evaluate the effectiveness of this system. Nuclear magnetic resonance imaging (NMRI) was used to visualize microbial polymer production in porous media. Changes in fluid distribution within the pore system of the core were ...

1995-12-31

128

A multidisciplinary study investigating radiotherapy in Ewing's sarcoma: end results of POG no. 8346  

International Nuclear Information System (INIS)

Purpose: To determine if involved field radiation (IF) is equivalent to standard whole bone radiation (SF) in local tumor control; to establish patterns of failure following treatment; and to determine response, event-free survival (EFS), and overall survival rates from multidisciplinary therapy in Ewing's sarcoma. Methods and Materials: Between 1983 and 1988, 184 children with Ewing's sarcoma were enrolled onto Pediatric Oncology Group 8346 (POG 8346). A total of 178 (97%) met eligibility criteria; 6 had pathology other than Ewing's sarcoma. Induction chemotherapy of cyclophosphamide/doxorubicin (adriamycin )(C/A) x 12 weeks was followed by local treatment either surgery or radiation therapy and C/A, dactinomycin, and vincristine for 50 weeks. Resection was advised for patients with small primary tumors if accomplished without functional loss. Forty patients were randomized to receive SF, whole bone radiation to 39.6 Gy plus a 16.2 Gy boost (total 55.8 Gy) or IF ...

1998-08-01

129

The poly dA helix: a new structural motif for high performance DNA-based molecular switches  

UK PubMed Central (United Kingdom)

We report a pH-dependent conformational transition in short, defined homopolymeric deoxyadenosines (dA15) from a single helical structure with stacked nucleobases at neutral pH to a double-helical,...Full Text Available

2009-05-01

130

Representations of the conformal Lie algebra in the space of tensor densities on the sphere  

CERN Document Server

Let ${\\mathcal F}_\\lambda(\\mathbb{S}^n)$ be the space of tensor densities on $\\mathbb{S}^n$ of degree $\\lambda$. We consider this space as an induced module of the nonunitary spherical series of the group $\\mathrm{SO}_0(n+1,1)$ and classify $(\\mathrm{so}(n+1,1),\\mathrm{SO}(n+1))$-sim$unitary submodules of ${\\mathcal F}_\\lambda(\\mathbb{S}^n)$ as a function of $\\lambda$.

2003-01-01

131

Prediction of conformational changes by single mutation in the hepatitis B virus surface antigen (HBsAg) identified in HBsAg-negative blood donors  

UK PubMed Central (United Kingdom)

BackgroundSelection of hepatitis B virus (HBV) by host immunity has been suggested to give rise to variants with amino acid substitutions at or around the 'a' determinant...Full Text Available

132

Emittance of investment casting molds  

Energy Technology Data Exchange (ETDEWEB)

This document describes measurements of the directional spectral emittance of four ceramic mold materials. The work was performed with the samples at {approximately} 900{degree}C in a vacuum vessel pumped to {approximately}3 {times} 10{sup {minus}6}Torr. Results conform to expectations derived from prior work done with similar samples.

1994-07-15

133

Depth of origin of the gas content in thermal waters  

Energy Technology Data Exchange (ETDEWEB)

The gas composition of recent thermal waters is in perfect conformity with their geologic-tectonic positions. The composition of gas-liquid inclusions in the basic-hyperbasic xenoliths of basaltoid lavas depends on the depth from which xenoliths are supplied. (The depth is determined by using the methods of geological thermobarometers). By comparing available data the conclusion was drawn that the gas compositions of thermal waters reflect the depth of generation of deep fluid which heats them and depends on the penetration depth of the fluid-conducting fissure zones.

1980-01-01

134

Cyclopeptide alkaloids. Synthesis of the ring system and its ion affinity  

International Nuclear Information System (INIS)

Several examples of the 14-membered, para-bridged ring system of the cyclopeptide alkaloids have been synthesized via an active ester cyclization. The yield of monomeric cyclopeptide varied from 1 to 33% and was affected by the amino acid substitution pattern and amide conformation of the linear peptide precursors. Both the synthetic models and a naturally occurring cyclopeptide alkaloid, ceanothine B, bind monovalent (Li"+) and divalent (Ca"2"+, Mg"2"+) cations. 4 figures, 1 table.

135

Conformational Changes in BAK, a Pore-forming Proapoptotic Bcl-2 Family Member, upon Membrane Insertion and Direct Evidence for the Existence of BH3-BH3 Contact Interface in BAK Homo-oligomers*  

UK PubMed Central (United Kingdom)

During apoptosis, the pro-apoptotic Bcl-2 family proteins BAK and BAX form large oligomeric pores in the mitochondrial outer membrane. Apoptotic factors, including cytochrome c, are...Full Text Available

2010-09-10

136

Adenine and guanine recognition of stop codon is mediated by different N domain conformations of translation termination factor eRF1  

UK PubMed Central (United Kingdom)

Positioning of release factor eRF1 toward adenines and the ribose-phosphate backbone of the UAAA stop signal in the ribosomal decoding site was studied using messenger RNA (mRNA) analogs containing...Full Text Available

2011-09-01

137

ATP Hydrolysis in Eg5 Kinesin Involves a Catalytic Two-water Mechanism*?  

UK PubMed Central (United Kingdom)

Motor proteins couple steps in ATP binding and hydrolysis to conformational switching both in and remote from the active site. In our kinesin·AMPPPNP crystal structure, closure of the active...Full Text Available

2010-02-19

138

Large scale magnetic field measurements and mapping  

CERN Document Server

Large scale magnetic field measurements and mapping

1984-01-01

139

FIELD CORROSION TESTS FOR COMPARISON OF ...  

Science.gov (United States)

... Accession Number : ADD457408. Title : FIELD CORROSION TESTS FOR COMPARISON OF CORROSIVITY IN JAPAN AND CHINA. ...

140

Tertiary structure prediction of C-peptide of ribonuclease A by multicanonical algorithm  

CERN Document Server

We have performed multicanonical Monte Carlo simulations of C-peptide of ribonuclease A. It is known by CD and NMR experiments that this peptide has high alpha-helix content in aqueous solution and that the side-chain charges of residues Glu-2$^-$ and His-12$^+$ play an important role in the stability of the alpha-helix. In order to confirm these experimental implications, we have used two analogues of the peptide with charged and neutral side chains of Glu-2 and His-12. Two dielectric functions, distance-dependent and constant, are considered to study the effects of solvent contributions. All the simulations were started from random initial conformations. Various thermodynamic quantities such as average helicity as a function of residue number and average distance between two side chains as a function of temperature are calculated. The results are found to be in accord with the implications of CD and NMR experiments. The lowest-energy ...

1998-01-01

141

Synthesis of alkylated deoxyno irimycin and 1,5-dideoxy-1,5-iminoxylitol analogues: : Polar side-chain modification, sulfonium and selenonium heteroatom variants, conformational analysis, and evaluation as glycosidase inhibitors  

DEFF Research Database (Denmark)

The syntheses of N-alkylated deoxynojirimycin and 1,5-dideoxy-1,5-iminoxylitol derivatives having either a D- or an L-erythritol-3-sulfate functionalized N-substituent are reported. The alkylating agent used was a cyclic sulfate derivative, whereby selective attack of the nitrogen atom at the least hindered primary center afforded the desired ammonium salt. In aqueous solution, these salts were configurationally labile at the ammonium center. Sulfonium and/or selenonium analogues of the ammonium salts were prepared by analogous reactions. The chalcogen salts were obtained as mixtures of diastereomers, separable in some cases, differing only in the stereochemistry at the configurationally stable sulfur or selenium atoms. Proof of configuration and conformation of each compound was obtained by detailed NMR experiments. The compounds are six-membered ring analogues of salacinol, a known sulfonium-salt glucosidase inhibitor. Evaluation of the target compounds for ...

2004-01-01

142

New Insights into the Design of Inhibitors of Human S-Adenosylmethionine Decarboxylase: Studies of Adenine C[superscript 8] Substitution in Structural Analogues of S-Adenosylmethionine  

Energy Technology Data Exchange (ETDEWEB)

S-Adenosylmethionine decarboxylase (AdoMetDC) is a critical enzyme in the polyamine biosynthetic pathway and depends on a pyruvoyl group for the decarboxylation process. The crystal structures of the enzyme with various inhibitors at the active site have shown that the adenine base of the ligands adopts an unusual syn conformation when bound to the enzyme. To determine whether compounds that favor the syn conformation in solution would be more potent AdoMetDC inhibitors, several series of AdoMet substrate analogues with a variety of substituents at the 8-position of adenine were synthesized and analyzed for their ability to inhibit hAdoMetDC. The biochemical analysis indicated that an 8-methyl substituent resulted in more potent inhibitors, yet most other 8-substitutions provided no benefit over the parent compound. To understand these results, we used computational modeling and X-ray crystallography to study C{sup 8}-substituted adenine ...

2009-04-02

143

Four small puzzles that Rosetta doesn't solve  

CERN Document Server

A complete macromolecule modeling package must be able to solve the simplest structure prediction problems. Despite recent successes in high resolution structure modeling and design, the Rosetta software suite fares poorly on deceptively small protein and RNA puzzles, some as small as four residues. To illustrate these problems, this manuscript presents extensive Rosetta results for four well-defined test cases: the 20-residue mini-protein Trp cage, an even smaller disulfide-stabilized conotoxin, the reactive loop of a serine protease inhibitor, and a UUCG RNA tetraloop. In contrast to previous Rosetta studies, several lines of evidence indicate that conformational sampling is not the major bottleneck in modeling these small systems. Instead, approximations and omissions in the Rosetta all-atom energy function currently preclude discriminating experimentally observed conformations from de novo models at atomic resolution. These molecular ...

2011-01-01

144

Enzymatic synthesis and carbon-13 nuclear magnetic resonance conformational studies of disaccharides containing #beta#-D-galactopyranosyl and #beta#-D-[1-"1"3C]Galactopyranosyl residues  

International Nuclear Information System (INIS)

Partially purified UDPgalactosyltransferase (EC 2.4.1.22) from bovine milk has been used to synthesize millimolar amounts of compounds such as Gal#beta#(1#->#4)Glc, Gal#beta#(1#->#4)GlcNAc-#beta#-hexanolamine, and Gal#beta#(1#->#4)-GlcNAc#beta#(1#->#4)GlcNAc. The same method has been used to prepare similar compounds containing "1"3C-enriched galactopyranosyl moieties. Gal#beta#(1#->#4)GlcNAc-#beta#-hexanolamine was also synthesized in a solid-phase system in which the GlcNAc-#beta#-hexanolamine glycoside was covalently linked to agarose beads. At pH 7.0 and at 1 to 5 mM Mn"2"+"+ the yields of the galactosyl saccharides are greater than 90% by using 10% excess of UDPGal donor. The use of a 90% enriched [1-"1"3C]galactosyl residue allowed the determination of the most abundant conformer about the galactopyranosyl-glycoside linkage by analysis of the carbon-carbon coupling constants from Cl to Gal to the C3', C4', and C5' of GlcNAc or Glc. 3 figures, 1 ...

145

Effect of water content on the activity of lipase-hydrolysis of olive oil in reverse micelles. Gyakuso micelle nai ni okeru lipase no olive oil kasui bunkai hanno no gansuiritsu izonsei  

Energy Technology Data Exchange (ETDEWEB)

Hydrolysis of olive oil by Chromobacterium viscosum lipase was studied in a reverse micellar system of a anionic surfactant Aerosol OT (AOT) and isooctane. Different methods of solubilization of the micellar system afford specific dependence of enzymatic activity of the lipase on the water content in the micelles. In an injection method, water content is controlled by the amount of injected water, which determines the micelle size and hydrophobicity of the micelle without salt addition and changes reversibly the conformation of lipase corresponding to the change of lipase activity. The activity reaches the maximum at a water content (water/AOT)of 7. In a phase transfer method, water content is determined by salt concentration in the aqueous phase in contact with micelles and the water content corresponding to the maximum activity is 12 to 13, below which the activity decrese drastically. Addition of taurodeoxycholic acid to the AOT micelles suppresses the ...

1992-01-10

146

Detection of constitutive heterodimerization of the integrin Mac-1 subunits by fluorescence resonance energy transfer in living cells  

International Nuclear Information System (INIS)

Macrophage differentiation antigen associated with complement three receptor function (Mac-1) belongs to #beta#_2 subfamily of integrins that mediate important cell-cell and cell-extracellular matrix interactions. Biochemical studies have indicated that Mac-1 is a constitutive heterodimer in vitro. Here, we detected the heterodimerization of Mac-1 subunits in living cells by means of two fluorescence resonance energy transfer (FRET) techniques (fluorescence microscopy and fluorescence spectroscopy) and our results demonstrated that there is constitutive heterodimerization of the Mac-1 subunits and this constitutive heterodimerization of the Mac-1 subunits is cell-type independent. Through FRET imaging, we found that heterodimers of Mac-1 mainly localized in plasma membrane, perinuclear, and Golgi area in living cells. Furthermore, through analysis of the estimated physical distances between cyan fluorescent protein (CFP) and yellow fluorescent protein (YFP) fused to Mac-1 subunits, we ...

2006-08-04

147

Density functional calculations of 15N chemical shifts in solvated dipeptides  

International Nuclear Information System (INIS)

We performed density functional calculations to examine the effects of solvation, hydrogen bonding, backbone conformation, and the side chain on 15N chemical shielding in proteins. We used N-methylacetamide (NMA) and N-formyl-alanyl-X (with X being one of the 19 naturally occurring amino acids excluding proline) as model systems. In addition, calculations were performed for selected fragments from protein GB3. The conducting polarizable continuum model was employed to include the effect of solvent in the density functional calculations. Our calculations for NMA show that the augmentation of the polarizable continuum model with the explicit water molecules in the first solvation shell has a significant influence on isotropic 15N chemical shift but not as much on the chemical shift anisotropy. The difference in the isotropic chemical shift between the standard ?-sheet and ?-helical conformations ranges from 0.8 to 6.2 ppm depending on the residue ...

2008-06-01

148

Coal structure construction system with construction knowledge and partial energy evaluation; Kochiku chishiki to bubunteki energy hyoka ni yoru sekitan bunshi kozo kochiku system  

Energy Technology Data Exchange (ETDEWEB)

The computer aided coal structure construction system is proposed, and a computational construction example is presented. The coal structure construction engine of this system fabricates molecular structure by connecting fragments sequentially inputted through a user interface. The best structure candidate is determined using construction knowledge and partial energy evaluation every addition of one fragment, and this process is subsequently repeated. The structure evaluation engine analyzes the 3-D conformation candidate by molecular dynamics, and evaluates the conformation by determining the energy value of an optimum structure. As an example, this system was applied to construction of coal molecular structure based on the actual data of partial structure composed of 26 structures from 2l kinds of aromatic cluster structures, 27 bonds from 2 kinds of bridged bonds, and 16 groups from 2 kinds of terminal substitutional groups. As a result, ...

1996-10-28

149

Waste Sampling and Characterization Facility (WSCF). Maintenance Implementation Plan  

Energy Technology Data Exchange (ETDEWEB)

This Maintenance Implementation Plan has been developed for maintenance functions associated with the Waste Sampling and Characterization Facility (WSCF). This plan is developed from the guidelines presented by Department of Energy (DOE) Order 4330.4A, Maintenance Management Program (DOE 1990), Chapter II. The objective of this plan is to provide baseline information for establishing and identifying WHC conformance programs and policies applicable to implementation of DOE order 4330.4A guidelines. In addition, this maintenance plan identifies the actions necessary to develop a cost-effective and efficient maintenance program at WSCF.

1993-07-01

150

Radiological performance assessment for the E-Area Vaults Disposal Facility  

Energy Technology Data Exchange (ETDEWEB)

This report is the first revision to ``Radiological Performance Assessment for the E-Area Vaults Disposal Facility, Revision 0'', which was issued in April 1994 and received conditional DOE approval in September 1994. The title of this report has been changed to conform to the current name of the facility. The revision incorporates improved groundwater modeling methodology, which includes a large data base of site specific geotechnical data, and special Analyses on disposal of cement-based wasteforms and naval wastes, issued after publication of Revision 0.

2000-04-11

151

Production of a potassium silicate fertilizer from fly ash and red mud  

Energy Technology Data Exchange (ETDEWEB)

A study is reported of the use of three types of fly ash as a raw material in the production of a potassium silicate fertilizer. The results of high-temperature X-ray diffraction, calcination tests and chemical analyses indicate that a potassium silicate fertilizer conforming with fertilizer specifications can be produced by appropriate regulation of calcining temperature and the amounts of Fe/sub 2/0/sub 3/, Al/sub 2/O/sub 3/, MgO and CaO added. The results of tests of fertilizers incorporating red mud are also reported.

1985-01-01

152

Performance of rubber heat-stable and radiation-stable seals in helium coolant lines  

International Nuclear Information System (INIS)

The integrity of helium circulation loop flanged joints has been attracting recent attention as a design problem, in the development of high-temperature facilities incorporating helium loops (e.g., the VRG-50 pilot nuclear facility). Elevated temperatures and pressures, and the radiation environment, impose additional requirements on sealant materials. This applies first and foremost to rubber seals, which have found widespread favor on account of its excellent elasticity, its ability to spontaneously conform to possible changes in the clearance in the seal assembly, and the low compressive stresses developed in the flange joint assembly.

153

Microeconomics of the ideal gas like market models  

CERN Document Server

We develop a framework based on microeconomic theory from which the ideal gas like market models can be addressed. A kinetic exchange model based on that framework is proposed and its distributional features have been studied by considering its moments. Next, we derive the moments of the CC model (Eur. Phys. J. B 17 (2000) 167) as well. Some precise solutions are obtained which conform with the solutions obtained earlier. Finally, an output market is introduced with global price determination in the model with some necessary modifications.

2009-01-01

154

Kasner asymptotics of mixmaster Horava-Witten and pre-big-bang cosmologies  

Energy Technology Data Exchange (ETDEWEB)

We discuss various superstring effective actions and, in particular, their common sector which leads to the so-called pre-big-bang cosmology (cosmology in a weak coupling limit of heterotic superstring theory). Using the conformal relationship between these two theories we present Kasner asymptotic solutions of Bianchi type IX geometries within these theories and make predictions about possible emergence of chaos. Finally, we present a possible method of generating Horava-Witten cosmological solutions out of the well-known general relativistic or pre-big-bang solutions.

2001-09-01

155

Kasner asymptotics of mixmaster Horava-Witten and pre-big-bang cosmologies  

International Nuclear Information System (INIS)

We discuss various superstring effective actions and, in particular, their common sector which leads to the so-called pre-big-bang cosmology (cosmology in a weak coupling limit of heterotic superstring theory. Using the conformal relationship between these two theories we present Kasner asymptotic solutions of Bianchi type IX geometries within these theories and make predictions about possible emergence of chaos. Finally, we present a possible method of generating Horava-Witten cosmological solutions out of the well-known general relativistic or pre-big-bang solutions.

2001-09-01

156

Gas-liquid phase equilibrium in the system carbon dioxide-hexametapol (hexamethylphosphoramide)  

Energy Technology Data Exchange (ETDEWEB)

The authors investigated phase equilibria in the system carbon dioxide-hexametapol. Vacuum-distilled solvent of ''pure'' grade was used. The solubility of CO/sub 2/ in hexametapol under pressures at various temperatures and the temperature dependence of the Henry's law coefficient is show. It is concluded that the solubility of carbon dioxide in hexametapol in the temperature and pressure ranges corresponding to the operating conditions of industrial equipment for removing CO/sub 2/ from gases conforms to the Krichevskii-II'inskaya equation. The experimental data can be used for equipment design.

1985-09-01

157

Documentation of a model action plan to deter illicit nuclear trafficking  

International Nuclear Information System (INIS)

Theft, illegal possession, smuggling, or attempted unauthorized sale of nuclear and radiological materials remains a worldwide problem. The Nuclear Smuggling International Technical Working Group (ITWG) has adopted a model action plan to guide investigation of these cases through a systematic approach to nuclear forensics. The model action plan was recently documented and provides recommendations concerning incident response, collection of evidence in conformance with required legal standards, laboratory sampling and distribution of samples, radioactive materials analysis, including categorization and characterization of samples, forensics analysis of conventional evidence, and case development including interpretation of forensic signatures. (author)

2008-05-01

158

Digital AVR application to power plants  

Energy Technology Data Exchange (ETDEWEB)

The digital AVR must have the level of redundancy and control functions that conform to the configuration of the excitation control system and to the importance of a particular generator for the user. The digital AVR is not simply a digital version of the analog AVR, but can realize sophisticated control functions that were difficult to achieve with analog circuits, thus making it possible to enhance the stability of power system by PSS (power system stabilizer). This paper describes the test results of the digital AVRs applied to power plants, their system configuration and functions, as well as the outline of an auto-tuning PSS or AT-PSS planned to be incorporated in the digital AVR in the future.

1993-12-01

159

Determination of fast neutron flux distribution in irradiation sites of the Malaysian Nuclear Agency research reactor  

British Library Electronic Table of Contents (United Kingdom)

Determination of thermal to fast neutron flux ratio (ffast) and fast neutron flux (phi-fast) is required for fast neutron reactions, fast neutron activation analysis, and for correcting interference reactions. The ffast and subsequently phi-fast were determined using the absolute method. The ffast ranged from 48 to 155, and the phi-fast was found in the range 1.03x1010-4.89x1010 n cm-2 s-1. These values indicate an acceptable conformity and applicable for installation of the fast neutron facility at the MNA research reactor.

2011-01-01

160

Chiral crystallization and the origin of chiral life on earth  

British Library Electronic Table of Contents (United Kingdom)

Abstract The creation of chirality on Earth and the development of chiral life have been discussed in this highlight. Convincing evidence for the introduction of chirality on Earth is still fragmentary. We believe that by a combination of chiral crystallization and formation of helical polymers with preferred chiral conformational structure is the key to this question. This concept of macromolecular asymmetry has inspired ideas and resulted in possible rules for how chiral life as we know it, could have been introduced. These investigations needed the understanding of the requirements for chiral crystallization, for the stereochemistry of the initial formation of helical polymers, the measurements of optical activity of solids and their coordination with the fundamentals of chirality. Spac...

2011-01-01

161

Adsorption of benzyl alcohol and 1-phenylethanol on graphitized thermal carbon black  

British Library Electronic Table of Contents (United Kingdom)

The adsorption of benzyl alcohol and 1-phenylethanol on graphitized thermal carbon black at 300 K is investigated. Thermodynamic characteristics of the adsorption of conformers stable in the gas phase and in the adsorbed state are determined by a molecular statistics method. The geometry of the molecules is optimized using the MP2 and B3LYP methods with a 6-311++G(d,p) basis set. Using the PBE0/6-31G(d) method, it is established that, in the adsorption of benzyl alcohol, two types of interactions, CH?O and OH??GTCB, occur. It is shown that, in 1-phenylethanol, intramolecular interactions are maintained.

2010-01-01

162

Actions for the environment  

CERN Document Server

As an International Organization, one the most important issues that CERN has to respect and guarantee is the protection of the environment. Several of ST activities and operations have a direct impact on the environment: civil engineering works, electrical (transformers) and air-cooling operation, chemical products storage, various waste disposal etc.... Important measures, taken in the past, have to be kept and new ones should be applied in order to insure the conformity of the infrastructure with existing legislation, the correct operation of equipment and systems, the constant monitoring of the different situations and the traceability of the events. Moreover good management of the environment would bring large savings to CERN.

2003-01-01

163

Acceptance test of full scope simulator of Daya Bay NPP  

International Nuclear Information System (INIS)

The author describes the purpose, classification and main process of acceptance test of full scope simulator of Daya Bay Nuclear Power Plant, including the correction of non-conformance items which are discovered during the performance of acceptance tests. The results of the acceptance tests show that the model accepted by the full scope simulator of Daya Bay Nuclear Power Plant is fully able to cope with the simulation of normal transients and incidental transients and the performance of the simulator indeed compiled with the technical specifications which are defined n the relevant contracts.

164

Algebraic complexities and algebraic curves over finite fields  

UK PubMed Central (United Kingdom)

We consider the problem of minimal (multiplicative) complexity of polynomial multiplication and multiplication in finite extensions of fields. For infinite fields minimal complexities are known [Winograd,...Full Text Available

1987-04-01

169

Tachyons in field theory  

International Nuclear Information System (INIS)

The conventional treatment of quantum field theories including tachyons is presented, in particular the phi"4 theory. (W.D.L.).

170

Tachyons as viewed from quantum field theory  

International Nuclear Information System (INIS)

The authors present a summary of the present state of the quantum field theory of tachyons. (W.D.L.).

171

Prospects of robotics research in the field of remote handling systems  

International Nuclear Information System (INIS)

The main trends of research carried out in remote handling systems in the fields of ergonomy, robotics and reliability are presented.

172

Metals and alloys : atmospheric corrosion testing : General requirements for field tests  

CERN Document Server

Metals and alloys : atmospheric corrosion testing : General requirements for field tests

1992-01-01

173

Low-frequency fields - sources and exposure  

International Nuclear Information System (INIS)

The author briefly discusses definition of terms, gives an introduction to measurement techniques and describes the characteristics of various low-frequency fields and their causes using typical examples: natural electric fields (thunderstroms), natural magnetic fields, technical electric constant fields (urban transportation, households), static magnetic fields (urban transportation, nuclear magnetic resonance imaging), technical electric alternating fields (high-voltage transmission lines, households), and magnetic alternating fields (high-voltage transmission lines). The author discusses both occupational exposure and that of the general public while underpinning his statements by numerous tables, measurement diagrams and charts. (Uhe).

1993-06-01

174

Geometric and topological methods for quantum field theory  

CERN Document Server

An introduction to recent developments in several active topics at the interface between algebra, geometry, topology and quantum field theory

2010-01-01

175

FINITE ELEMENT OPTIMIZATION OF FIELD ...  

Science.gov (United States)

... Title : FINITE ELEMENT OPTIMIZATION OF FIELD CONFIGURATION FOR THE EDDY CURRENT TESTING OF ROLLER BEARING RIB RINGS. ...

1988-04-01

176

A bright field scanning transmission electron microscope (STEM ...  

Science.gov (United States)

A bright field scanning transmission electron microscope (STEM) micrograph showing a Wassonite grain in dark contrast. ...

177

On the Bottom Magnetic Fields of the Millisecond Pulsars  

CERN Document Server

The magnetic field strengths of most millisecond pulsars(MSP) are about $10^{8-9}$ Gauss. The accretion induced magnetic field evolution scenario here concludes that the field decay is invesely related to the accreted mass and the minimum field or bottom field stops at about $10^{8}$ Gauss if accreted with the Eddington accretion rate, which is proportionally related with the accretion rate as $\\dot{M}^{1/2}$. The possibility of the low field $\\sim 10^{7}$ Gauss MSPs has been proposed for the future radio observation.

2003-01-01

178

Is uniform target dose possible in IMRT plans in the head and neck?  

International Nuclear Information System (INIS)

Purpose: Various published reports involving intensity-modulated radiotherapy (IMRT) plans developed using automated optimization (inverse planning) have demonstrated highly conformal plans. These reported conformal IMRT plans involve significant target dose inhomogeneity, including both overdosage and underdosage within the target volume. In this study, we demonstrate the development of optimized beamlet IMRT plans that satisfy rigorous dose homogeneity requirements for all target volumes (e.g., #+-#5%), while also sparing the parotids and other normal structures. Methods and Materials: The treatment plans of 15 patients with oropharyngeal cancer who were previously treated with forward-planned multisegmental IMRT were planned again using an automated optimization system developed in-house. The optimization system allows for variable sized beamlets computed using a three-dimensional convolution/superposition dose calculation and flexible cost ...

2002-04-01

179

Epitope mapping and functional analysis of sigma A and sigma NS proteins of avian reovirus  

International Nuclear Information System (INIS)

We have previously shown that avian reovirus (ARV) #sigma#A and #sigma#NS proteins possess dsRNA and ssRNA binding activity and suggested that there are two epitopes on #sigma#A (I and II) and three epitopes (A, B, and C) on #sigma#NS. To further define the location of epitopes on #sigma#A and #sigma#NS proteins and to further elucidate the biological functions of these epitopes by using monoclonal antibodies (MAbs) 62, 1F9, H1E1, and 4A123 against the ARV S1133 strain, the full-length and deletion fragments of S2 and S4 genes of ARV generated by polymerase chain reaction (PCR) were cloned into pET32 expression vectors and the fusion proteins were overexpressed in Escherichia coli BL21 strain. Epitope mapping using MAbs and E. coli-expressed deletion fragments of #sigma#A and #sigma#NS of the ARV S1133 strain, synthetic peptides, and the cross reactivity of MAbs to heterologous ARV strains demonstrated that epitope II on #sigma#A was located at amino acid residues ...

2005-02-20

180

Effect of D-amino acids at Asp"2"3 and Ser"2"6 residues on the conformational preference of A#beta#_2_0_-_2_9 peptides  

International Nuclear Information System (INIS)

The effects of D-amino acids at Asp"2"3 and Ser"2"6 residues on the conformational preference of #beta#-amyloid (A#beta#) peptide fragment (A#beta#_2_0_-_2_9) have been studied using different spectroscopic techniques, namely vibrational circular dichroism (VCD), vibrational absorption, and electronic circular dichroism. To study the structure of the A#beta#_2_0_-_2_9, [D-Asp"2"3]A#beta#_2_0_-_2_9, and [D-Ser"2"6]A#beta#_2_0_-_2_9 peptides under different conditions, the spectra were measured in 10 mM acetate buffer (pH 3) and in 2,2,2-trifluoroethanol (TFE). The spectroscopic results indicated that at pH 3, A#beta#_2_0_-_2_9 peptide takes random coil with #beta#-turn structure, while [D-Ser"2"6]A#beta#_2_0_-_2_9 peptide adopts significant amount of polyproline II (PPII) type structure along with #beta#-turn contribution and D-Asp-substituted peptide ([D-Asp"2"3]A#beta#_2_0_-_2_9) adopts predominantly PPII type structure. The increased propensity for PPII ...

2005-09-30

181

J/Psi dissociation in parity-odd bubbles  

CERN Document Server

We calculate the quarkonium dissociation rate in the P and CP-odd domains (bubbles) that were possibly created in heavy-ion collisions. In the presence of the magnetic field produced by the valence quarks of colliding ions, parity-odd domains generate electric field. Quarkonium dissociation is the result of quantum tunneling of quark or antiquark through the potential barrier in this electric field. The strength of the electric field in the quarkonium comoving frame depends on the quarkonium velocity with respect to the background magnetic field. We investigate momentum, electric field strength and azimuthal dependence of the dissociation rate. Azimuthal distribution of quarkonia surviving in the electromagnetic field is strongly anisotropic; the form of anisotropy depends on the relation between the electric and magnetic ...

2011-01-01

182

The ribosome and the mechanism of protein synthesis  

Energy Technology Data Exchange (ETDEWEB)

In virtually all forms of life on earth, proteins in each cell are made according to a genetic blueprint, in the form of DNA. The translation of copies of this genetic blueprint (in the form of messenger RNA) into polypeptides is performed on the ribosome, a highly complex molecular machine composed of RNAs and proteins. To this end, special adaptor molecules called transfer RNAs are lined up by the ribosome in the sequence dictated by the genetic code, such that the amino acids carried by these molecules can be linked into a polypeptide. Several cofactors are involved in these processes, some of which require energy freed up by GTP hydrolysis. Although the ribosome was discovered more than 50 years ago, its structure has only been solved recently by X-ray crystallography. Another technique, cryo-electron microscopy, is starting to contribute toward our understanding of the ribosome's function, by portraying its conformational changes and binding ...

2006-05-01

183

Stop-and-go kinetics in amyloid fibrillation  

CERN Document Server

Many human diseases are associated with protein aggregation and fibrillation. We present experiments on in vitro glucagon fibrillation using total internal reflection fluorescence microscopy, providing real-time measurements of single-fibril growth. We find that amyloid fibrils grow in an intermittent fashion, with periods of growth followed by long pauses. The observed exponential distributions of stop and growth times support a Markovian model, in which fibrils shift between the two states with specific rates. Remarkably, the probability of being in the growing (stopping) state is very close to 1/4 (3/4) in all experiments, even if the rates vary considerably. This finding suggests the presence of 4 independent conformations of the fibril tip; we discuss this possibility in terms of the existing structural knowledge.

2009-01-01

184

Regulations on health/functional foods in Korea  

International Nuclear Information System (INIS)

The term 'health/functional food' (HFF) refers to food supplements containing nutrients or other substances (in a concentrated form) that have a nutritional or physiological effect whose purpose is to supplement the normal diet. The Korean Health/Functional Food Act that came into effect in 2004 requires these products to be marketed in measured doses, such as in pills, tablets, capsules, and liquids. HFFs are of two types: generic and product-specific. There are 37 ingredients listed in the act for generic HFFs, and if an HFF contains a new active ingredient that is not included in the generic 37 products, it is considered a product-specific HFF. The standardization, safety, and efficacy of a new active ingredient are reviewed by the Korean Food and Drug Administration in order to receive approval as a product-specific HFF. Conforming with international standards and protecting public health requires constant upgrading of the Health/Functional Food Act.

2006-04-03

185

Radiation therapy in the treatment of hilar cholangiocarcinoma  

International Nuclear Information System (INIS)

The incidence of hilar cholangiocarcinoma is very rare worldwide. Radical resection is the only prognostic factor for long survival in patients with hilar cholangiocarcinoma. Postoperative radiation therapy can improve local control and survival rates for patients with palliative resection, but it remains controversial in patients with radical resection. Biliary drainage can effectively release bile duct obstruction for the majority of patients with locally advanced disease, and may even prolong survival when combined with radiation therapy. Radiation therapy includes extrernal beam therapy alone, external beam therapy with intraluminal brachytheapy and new radiation technique, such as three dimentional conformal therapy and intensity modulated radiation therapy. The propective randomized clinical study is needed for further investigation in the role of combined modality therapy especially for hilar cholangiocarcinoma. (authors)

2007-10-01

186

Radiation therapy and Ewing's sarcoma in childhood  

International Nuclear Information System (INIS)

Despite high local control rate in Ewing's sarcoma the exact indication of radiation therapy is still controversial as well as the choice of the target volume and the optimal dose of radiation. The importance of the quality of radiotherapy has been stressed in recently published data and has shown a significant impact on long term local control with adequate radiation therapy. The dramatic improvement of precision allowed by the conformal therapy and three dimensional dosimetry allow to expect a decrease of late effects expected for second malignancies. However, late sequelae and radio-induced osteosarcoma still remain the major side effects after radiotherapy. The authors discuss the results of the main trials on Ewing's sarcoma on the choice of dose and target volume. Surgery is still the preferred choice for small tumors if the foreseen outcome is identical. (authors). 28 refs.

187

Numerical simulation of conformational variability in biopolymer translocation through wide nanopores  

CERN Document Server

Numerical results on the translocation of long biopolymers through mid-sized and wide pores are presented. The simulations are based on a novel methodology which couples molecular motion to a mesoscopic fluid solvent. Thousands of events of long polymers (up to 8000 monomers) are monitored as they pass through nanopores. Comparison between the different pore sizes shows that wide pores can host a larger number of multiple biopolymer segments, as compared to smaller pores. The simulations provide clear evidence of folding quantization in the translocation process as the biopolymers undertake multi-folded configurations, characterized by a well-defined integer number of folds. Accordingly, the translocation time is no longer represented by a single-exponent power law dependence on the length, as it is the case for single-file translocation through narrow pores. The folding quantization increases with the biopolymer length, while the rate of translocated beads at each time step is ...

2009-01-01

188

Non-destructive Imaging of Individual Bio-Molecules  

CERN Document Server

Radiation damage is considered to be the major problem that still prevents imaging an individual biological molecule for structural analysis. So far, all known mapping techniques using sufficient short wave-length radiation, be it X-rays or high energy electrons, circumvent this problem by averaging over many molecules. Averaging, however, leaves conformational details uncovered. Even the anticipated use of ultra-short but extremely bright X-ray bursts of a Free Electron Laser shall afford averaging over 10^6 molecules to arrive at atomic resolution. Here we present direct experimental evidence for non-destructive imaging of individual DNA molecules. In fact, we show that DNA withstands coherent low energy electron radiation with deBroglie wavelength in the Angstrom regime despite a vast dose of 10^8 electrons/nm^2 accumulated over more than one hour.

2009-01-01

189

Mapping of the human cone transducin {alpha}-subunit (GNAT2) gene to 1p13 and negative mutation analysis in patients with Stargardt disease  

Energy Technology Data Exchange (ETDEWEB)

We report localization of the human cone transducin (GNAT2) gene using fluorescence in situ hybridization on chromosome 1 in band p13. The recent assignment of a gene for Stargardt disease to the same chromosomal region by linkage analysis prompted us to investigate the possible role of GNAT2 in the pathogenesis of this disease. We investigated 66 unrelated patients for mutations in the coding region of the GNAT2 gene using polymerase chain reaction-single strand conformation polymorphism analysis (SSCP) and direct sequencing. No disease-specific mutations were found, indicating that GNAT2 is probably not involved in the pathogenesis of most cases of Stargardt disease. 19 refs., 1 fig., 1 tab.

1995-01-01

190

Kinetics of a reactive dye adsorption onto dolomitic sorbents.  

Science.gov (United States)

A novel wastewater treatment technique has been investigated, for reactive dye removal, in batch kinetic systems. These experimental studies have indicated that charred dolomite has the potential to act as an adsorbent for the removal of Brilliant Red reactive dye from aqueous solution. The effect of initial dye concentration, adsorbent mass:liquid volume ratio, and agitation speed on dye removal have been determined with the experimental data mathematically described using empirical external mass transfer and intra-particle diffusion models. The experimental data show conformity with an adsorption process, with the removal rate heavily dependent on both external mass transfer and intra-particle diffusion. PMID:12691893

2003-05-01

191

Kinetic manifestation of cooperative interaction between quinuclidinyl benzilate and rat brain muscarine cholinoreceptors  

Energy Technology Data Exchange (ETDEWEB)

A study was made of the kinetics of L-(/sup 3/H)quinuclidinyl benzilate binding with membrane-bound muscarine cholinoreceptors from the rat brain. Determination was made of the rate constants of this process, and constants as a function of ligand concentration was investigated, indicating that there is a complex mechanism of interaction of antagonists with muscarine receptor. With up to 3.5 nM concentrations of L-(/sup 3/H)quinuclidinyl benzilate, the binding reaction occurs in two stages: rapid equilibrated binding is followed by a slow process of conformational isomerization of the receptor-ligand complex. At higher ligand concentrations, there is additional drastic increase in constant of rate of ligand binding a new plateau is reached. Such dependence of rate constant on ligand concentration is indicative of the cooperative nature of interaction between antagonists and muscarine receptors. This is possible if there are in the receptor complex several binding ...

1985-01-01

192

K S Krishnan and the early experimental evidences for the Jahn-Teller Theorem  

CERN Document Server

Jahn-Teller theorem, proposed in 1937, predicts a distortional instability for a molecule that has symmetry based degenerate electronic states. In 1939 Krishnan emphasized the importance of this theorem for the arrangement of water molecules around the transition metal or rare earth ions in aqueous solutions and hydrated saltes, in a short and interesting paper published in Nature by pointing out atleast four existing experimental results in support of the theorem. This paper of Krishnan has remained essentially unknown to the practitioners of Jahn-Teller effect, eventhough it pointed to the best experimental results that were available, in the 30's and 40's, in support of Jahn-Teller theorem. Some of the modern day experiments are also in conformity with some specific suggestions of Krishnan.

1998-01-01

193

Interaction of insulin with a triblock copolymer of PEG-(fumaric-sebacic acids)-PEG: Thermodynamic and spectroscopic studies  

British Library Electronic Table of Contents (United Kingdom)

A comparative study on the interaction of (PEG-co-P(FA/SC)-co-PEG) triblock copolymer with bovine and human insulins was carried out using isothermal titration calorimetry (ITC), circular dichroism (CD), and fluorescence spectroscopy. ITC data show that the copolymer has a low affinity for both proteins, with an association constant of about 7?9?103?M ?1. Results also show that binding is enthalpically driven, and disfavored by conformational entropy. CD spectroscopy studies reveal a small increase in the helical content and a decrease in ?-structure as well as random coil in both proteins. Acrylamide quenching experiments display reduced accessibility of tyrosines, while intrinsic fluorescence spectra show lower tyrosine emission. Furthermore, thermal unfolding experiments, studied by far...

2007-01-01

194

Influence of recycling and temperature on the swelling ability of paper  

British Library Electronic Table of Contents (United Kingdom)

Hornification is the loss of fiber wall swelling which is detrimental to subsequent recycling resulting from drying. It is known that dried fibers lose their conformability and swelling capacity. The effect of recycling treatment on the swelling ability of hardwood bleached kraft pulp fibers was determined. Modelling paper recycling, sheets were recycled using heat treatment (23?C, 60?C, 100?C). The results were compared with those for natural fibers from bleached kraft pulp. Swelling kinetics of sheets was measured by a modified method monitoring interactions of pulp with water. Swelling ability decreased during the recycling in comparison with never-recycled pulp at all temperatures. Recycling of sheets caused only small changes in the cupri-ethylene-diamine viscosity, however, the water...

2011-01-01

195

Grading of quality assurance requirements  

International Nuclear Information System (INIS)

The present Manual provides guidance and illustrative examples for applying a method by which graded quality assurance requirements may be determined and adapted to the items and services of a nuclear power plant in conformance with the requirements of the IAEA Nuclear Safety Standards (NUSS) Code and Safety Guides on quality assurance. The Manual replaces the previous publication IAEA-TECDOC-303 on the same subject. Various methods of grading quality assurance are available in a number of Member States. During the development of the present Manual it was not considered practical to attempt to resolve the differences between those methods and it was preferred to identify and benefit from the good practices available in all the methods. The method presented in this Manual deals with the aspects of management, documentation, control, verification and administration which affect quality. 1 fig., 4 tabs.

196

Geothermal resource maps and bottom hole temperature surveys  

Energy Technology Data Exchange (ETDEWEB)

Knowledge of subsurface temperatures obtained from heat flow and equilibrium temperature measurements were used as a basis for evaluation of the usefulness of the non-equilibrium temperatures of oil and gas wells for geothermal exploration. We find that the data in the Geothermal Gradient Map of North America do not conform to the thermal regime of Nebraska; and, that if the BHT data were the only data used, we would have underestimated our resource by about 80%. Differences in geological sections and heat flow between Nebraska and the U.S. Gulf coast where the correction data for the USGS map were obtained are the reasons for the discrepency. Some significant inaccuracies in the BHT data may not be correctable.

1982-10-01

197

Experimental and theoretical investigation of amino acids dimers and associates adsorption on carbon surface  

British Library Electronic Table of Contents (United Kingdom)

The thermodynamic characteristics of adsorption (the Henry constant, the heat and entropy of adsorption) of amino acids associates with acetic, trifluoroacetic, nonafluoropentanoic acids and formamide with different values of hydrogen bond lengths and various conformations on a graphitized thermal carbon black (GTCB) were calculated. The experimental results, as the Henry constant, lnK1, and the differences in the molar Gibbs energies, d(DG), obtained by a high performance liquid chromatography (HPLC) on a carbon sorbent Hypercarb, were compared with the values of thermodynamic characteristics of adsorption of the amino acids on the GTCB surface calculated by a molecular-statistical method. A satisfactory correlation was observed between the experimental and calculated values with a coeffi...

2011-01-01

198

Exciplex processes involving trans naphthylethylenes. Implications of ground-state conformeric equilibria  

Energy Technology Data Exchange (ETDEWEB)

Five arylethylenes with 1-naphthyl, 2-naphthyl, and phenyl groups in 1,2-positions have been studied for singlet-mediated charge-transfer interactions with several amines and paraquat dication. 1-Phenyl-2-(2-naphthyl)ethylene and 1,2-di(2-naphthyl)ethylene exhibit distinct dependence of exciplex emission maxima and lifetimes, and fluorescence quenching constants, on excitation and/or monitoring wavelengths; this is in conformity with the existence of ground-state rotamers for these systems, wtih distinguishable absorption-emission spectra and fluorescence lifetimes. The fluorescence quenching by aromatic amines and paraquat dication occurs with rate constants in the limit of diffusion control and is accompanied by the formation of radical ions in polar solvents (acetonitrile). The transient spectra and kinetics associated with the radical ions, observed by 337.1- and 355-nm laser flash photolysis, are also reported. 10 figures, 4 tables.

1983-05-12

199

Energy value as a factor of agroforestry wood species selectivity in Akinyele and Ido local government areas of Oyo State, Nigeria  

British Library Electronic Table of Contents (United Kingdom)

Wood usage for cooking and heating is still very relevant in most developing countries especially those of sub-Saharan Africa and many parts of Asia. Therefore, sustainable means of generating it for this and other purposes are necessary bearing in mind the influence of indigenous knowledge/users perspective on any production method regarding success and sustenance. In conformity with this view, questionnaires were administered on 240 respondents in 8 rural communities of Akinyele and Ido Local Government Areas (LGAs) of Oyo State, Nigeria, to elicit information on species that can be used as fuelwood, preferred by the respondents for incorporation into and/or retention in agroforestry plots, out of which 179 (i.e. 75% of the total number of questionnaires administered) were successfully r...

2009-01-01

200

Effect of strongly coupled plasma on the spectra of hydrogenlike carbon, aluminium and argon  

Science.gov (United States)

A detailed study has been performed for estimating the orbital energies, positions and shifts of the Lyman lines of C5+, Al12+ and Ar17+ under strongly coupled plasma with a view to understand such line positions and shifts obtained in laser produced plasma experiments. The effect of strongly coupled plasma has been treated within the Ion Sphere (IS) model. Both non-relativistic and relativistic methods have been used for estimating the spectral properties. Theoretical estimates with IS model of the plasma are in conformity with the results of laser plasma experiments on these highly stripped ions. The experimental data for the systems have also been compared with the theoretical estimates using Debye screening model of the plasma with spatial confinements which gives additional restrictions to the wave functions at finite boundaries.

2008-01-01

201

Diphtheria toxoid conformation in the context of its nanoencapsulation within liposomal particles sandwiched by chitosan  

British Library Electronic Table of Contents (United Kingdom)

Chitosan (a?-(1-4)-amino-2-deoxy-b?-D-glucan) is a deacetylated form of chitin, a polysaccharide from crustacean shells. Its unique characteristics, such as positive charge, biodegradability, biocompatibility, nontoxicity, and rigid structure, make this macromolecule ideal for an oral vaccine delivery system. We prepared reverse-phase evaporation vesicles (REVs) sandwiched by chitosan (Chi) and polyvinylic alcohol (PVA). However, in this method, there are still some problems to be circumvented related to protein stabilization. During the inverted micelle phase of protein nanoencapsulation, hydrophobic interfaces are expanded, leading to interfacial adsorption, followed by protein unfolding and aggregation. Here, spectroscopic and immunological techniques were used to ascertain the effects ...

2011-01-01

202

Development of sealing insulator for electric penetration assemblies  

International Nuclear Information System (INIS)

Electrical penetration assemblies mounted on the containment wall are used to carry electrical power and signals from the equipment inside this containment (e.g. recirculation pumps, control rod position indications etc.) Todays BWR nuclear power plants apply epoxy resin sealed electric penetration. Contrariwise, the epoxy resin (organic sealant) was replaced with sodium barium glass (inorganic) by way of trial in search for a quality sealant. The glass sealant has been proved to have high temperature airtightness at 300 degC above from an evaluation test involving full-scale model parts. Environmental tests were conducted continuously as to heat cycle, vibration and LOCA etc. the specimens (module) of five types. They were made certain of conformity to the design requirements for boiling water operation. (author).

203

Dendrosomes as novel gene porters-III  

British Library Electronic Table of Contents (United Kingdom)

BACKGROUND: It was previously reported that dendrosomes, i.e. neutral, biodegradable, covalent or self-assembled, hyperbranched, spheroidal nano-particles with a size ranging from 15 to 100 nm, provide a convenient and efficient means of gene delivery into various kinds of cells such as human hepatoma and kidney cells as well as animal models.RESULTS: New studies via circular dichroism show that hydrophilic and amphipathic dendrosomes either do not affect the DNA structure or moderately transform it from B- to A-conformation. Gene delivery into human liver, kidney, and endothelial cells as well as other animal cells like Bowes, U-937, Raw, CCRF-CEM, MOLT-4, K562, Huh-7 and VERO reveal that the genes are efficiently expressed and in comparison with other gene porters like Lipofectin or bact...

2008-01-01

204

Circular map for supercavitating flow in a multiply connected domain  

British Library Electronic Table of Contents (United Kingdom)

A nonlinear free boundary-value problem of supercavitating flow past n + 1 hydrofoils is analyzed. To describe the cavities' closure mechanism, the Tulin-Terentev single-spiral-vortex model is employed. The flow domain is considered as the image of an (n + 1)-connected circular domain. The conformal map is constructed in terms of the solutions to two Riemann-Hilbert problems of the theory of symmetric automorphic functions. One of the problems is homogeneous and its coefficients are continuous functions while the second problem is inhomogeneous and has discontinuous coefficients. The exact solutions to the problems are found by using quasiautomorphic and quasimultiplicative analogs of the Cauchy kernel. The case of a single plate is considered in detail and the numerical results are report...

2009-01-01

205

Chemical Analysis of Solid-State Irradiated Human Insulin  

British Library Electronic Table of Contents (United Kingdom)

Purpose To study the chemical modifications induced upon irradiation of solid human insulin at radiosterilization doses and investigate the influence of the absorbed dose on radiolysis. Materials and Methods Volatile radiolytic products were monitored by gas chromatography coupled with mass spectrometry (GC-MS) and non-volatile products by two different high performance liquid chromatography (HPLC) methods: the formation of higher molecular weight proteins was assessed by size exclusion liquid chromatography whereas assays for related compounds and chemical potency tests were carried out using reverse-phase HPLC-UV. Conformational changes were investigated by measurements of circular dichroism. Results After gamma irradiation at 10?kGy, the recovery of insulin was 96.8%; higher molecular w...

2006-01-01

206

Biological treatment of wine of distilleries  

International Nuclear Information System (INIS)

The potential of the yeast Candida tropicalis and Candida guillermondii was evaluated and an isolated partnership of microorganisms of waters of the Medellin River, conformed by two bacteria and one leavening, to degrade the content of organic matter present in wine produced by the factory of Licores and Alcoholes de Antioquia (FLA) in aerobic process with biomass production. For each one of the microorganisms in study this capacity of removal in units of chemical demand of oxygen was quantified (CDO); in addition, parameters were analyzed such as yield of the biomass in relation to the removed CDO and to total reducing sugars (TRS) consumed, time of fermentation and speed of growth different dilutions from wine. Also the possible inhibition was analyzed that the present phenolic compounds in this wine can cause in the biological process of degradation.

207

Bacteriophage P22 capsid size determination: Roles for the coat protein telokin-like domain and the scaffolding protein amino-terminus  

British Library Electronic Table of Contents (United Kingdom)

Assembly of icosahedral capsids of proper size and symmetry is not understood. Residue F170 in bacteriophage P22 coat protein is critical for conformational switching during assembly. Substitutions at this site cause assembly of tubes of hexamerically arranged coat protein. Intragenic suppressors of the ts phenotype of F170A and F170K coat protein mutants were isolated. Suppressors were repeatedly found in the coat protein telokin-like domain at position 285, which caused coat protein to assemble into petite procapsids and capsids. Petite capsid assembly strongly correlated to the side chain volume of the substituted amino acid. We hypothesize that larger side chains at position 285 torque the telokin-like domain, changing flexibility of the subunit and intercapsomer contacts. Thus, a sing...

2011-01-01

208

Assuring both quality and creativity in basic research  

Energy Technology Data Exchange (ETDEWEB)

How does one assure that both quality and creativity are obtained in basic research environments QA theoreticians have attempted to develop workable definitions of quality, but in more reflective moments, these definitions often fail to capture the deeper essence of the idea of quality.'' This paper asserts that creativity (as a product of the human mind) is a concrete interface between perfunctory definitions of quality (conformance to specifications) and more philosophical speculations about the nature of quality- related ultimates'' like elegance or beauty. In addition, we describe the distinction between creative ideas and creative acts and highlight one of the major inhibitors of creativity, fear. Finally we show that highly creative people often have an irreverent attitude toward boundaries and established authority, and discuss how one can allow for this when designing a QA program in a basic research environment.

1990-04-12

209

Assessment of GABARAP self-association by its diffusion properties  

Energy Technology Data Exchange (ETDEWEB)

Gamma-aminobutyric acid type A receptor-associated protein (GABARAP) belongs to a family of small ubiquitin-like adaptor proteins implicated in intracellular vesicle trafficking and autophagy. We have used diffusion-ordered nuclear magnetic resonance spectroscopy to study the temperature and concentration dependence of the diffusion properties of GABARAP. Our data suggest the presence of distinct conformational states and provide support for self-association of GABARAP molecules. Assuming a monomer-dimer equilibrium, a temperature-dependent dissociation constant could be derived. Based on a temperature series of {sup 1}H{sup 15}N heteronuclear single quantum coherence nuclear magnetic resonance spectra, we propose residues potentially involved in GABARAP self-interaction. The possible biological significance of these observations is discussed with respect to alternative scenarios of oligomerization.

2010-09-15

210

Adaptive Radiation Therapy for Localized Mesothelioma with Mediastinal Metastasis Using Helical Tomotherapy  

British Library Electronic Table of Contents (United Kingdom)

The purpose of this study was to compare 2 adaptive radiotherapy strategies with helical tomotherapy. A patient having mesothelioma with mediastinal nodes was treated using helical tomotherapy with pretreatment megavoltage CT (MVCT) imaging. Gross tumor volumes (GTVs) were outlined on every MVCT study. Two alternatives for adapting the treatment were investigated: (1) keeping the prescribed dose to the targets while reducing the dose to the OARs and (2) escalating the target dose while maintaining the original level of healthy tissue sparing. Intensity modulated radiotherapy (step-and-shoot IMRT) and 3D conformal radiotherapy (3DCRT) plans for the patient were generated and compared. The primary lesion and nodal mass regressed by 16.2% and 32.5%, respectively. Adapted GTVs and reduced plan...

2009-01-01

211

A retrospective study of canine hip dysplasia in 116 military workingn> dogs. Part I: Angle measurements and orthopedic foundation for animals (OFA) grading.  

Science.gov (United States)

The progression of hip dysplasia was investigated in 116 military working dogs. Serial pelvic radiographs were graded for degree of dysplasia and degenerative joint disease (DJD). Norberg angles, angles of inclination, and joint space widths were measured. There was a significant correlation between the Norberg angle and the degree of dysplasia (p less than 0.0001). Angles of inclination and joint space width measurements did not demonstrate a correlation to canine hip dysplasia. Dysplastic dogs had a significant estimated risk for development of DJD compared to normal dogs (p less than 0.0001; odds ratio of 70.2). Dogs with normal hip conformation at 24 months of age or older did not develop moderate nor severe DJD. PMID:8875357

212

A novel structural mechanism for redox regulation of uridine phosphorylase 2 activity  

British Library Electronic Table of Contents (United Kingdom)

Uridine phosphorylase (UPP) catalyzes the reversible conversion of uridine to uracil and ribose-1-phosphate and plays an important pharmacological role in activating fluoropyrimidine nucleoside chemotherapeutic agents such as 5-fluorouracil and capecitabine. Most vertebrate animals, including humans, possess two homologs of this enzyme (UPP1 & UPP2), of which UPP1 has been more thoroughly studied and is better characterized. Here, we report two crystallographic structures of human UPP2 (hUPP2) in distinctly active and inactive conformations. These structures reveal that a conditional intramolecular disulfide bridge can form within the protein that dislocates a critical phosphate-coordinating arginine residue (R100) away from the active site, disabling the enzyme. In vitro activity measurem...

2011-01-01

213

Multidipole magnetic fields for plasma confinement  

Energy Technology Data Exchange (ETDEWEB)

Plasma confinement by permanent magnets has been studied. An analytic formula for the field of a single bar magnet has been obtained. Generalization to various configurations of multidipole fields has also been found. Any two-dimensional field may now be completely described by a simple function of complex variables in closed form. Vector potential has also been obtained by integrating over a prescribed Riemann surface. The confinement of plasma by multidipole fields then becomes obvious through conservation principles.

1983-07-01

214

Interaction of tachyons with superluminal electromagnetic fields  

Energy Technology Data Exchange (ETDEWEB)

The study of interaction of tachyons with superluminal electromagnetic fields has been undertaken and it has been shown that the energy of this interaction is similar to that of bradyons with ordinary electromagnetic fields except that the roles of virtual and longitudinal parts are interchanged. It has also been shown that the interaction of tachyons with superluminal electromagnetic fields in time-energy representation is identical to the interaction of bradyons with ordinary electromagnetic fields in space-momentum representation. 19 references.

1983-04-01

215

Interaction of tachyons with superluminal electromagnetic fields  

International Nuclear Information System (INIS)

The study of interaction of tachyons with superluminal electromagnetic fields has been undertaken and it has been shown that the energy of this interaction is similar to that of bradyons with ordinary electromagnetic fields except that the roles of virtual and longitudinal parts are interchanged. It has also been shown that the interaction of tachyons with superluminal electromagnetic fields in time-energy representation is identical to the interaction of bradyons with ordinary electromagnetic fields in space-momentum representation. (author).

216

The effective longitudinal dielectric constant for plasmas in inhomogeneous magnetic fields  

Scientific Electronic Library Online (English)

Abstract in english We present a detailed derivation of the effective dielectric constant to be used in the dispersion relation for electrostatic waves in the case of a plasma immersed in a inhomogeneous magnetic field, with inhomogeneity perpendicular to the direction of the magnetic field.

2004-09-01

217

The current algebra on the circle as a germ of local field theories  

International Nuclear Information System (INIS)

Methods of algebraic quantum field theory are used to classify all field- and observable algebras, whose common germ is the U(1)-current algebra. An elementary way is described to compute characters of such algebras. It exploits the Kubo-Martin-Schwinger condition for Gibbs states. (orig.).

1988-03-01

218

Tachyons in stationary fields  

Energy Technology Data Exchange (ETDEWEB)

The authors have investigated here whether tachyons can move in stable circular orbits in Kerr, Kerr-Newmann and Lewis fields owing to their dragging effect. It is found that stable circular orbits are possible only in a Lewis field.

1981-07-01

219

Tachyons in stationary fields  

International Nuclear Information System (INIS)

The authors have investigated here whether tachyons can move in stable circular orbits in Kerr, Kerr-Newmann and Lewis fields owing to their dragging effect. It is found that stable circular orbits are possible only in a Lewis field. (author).

220

Study of particles trapped by a magnetic field  

Science.gov (United States)

A new type of radiation which occurs when particles are accelerated in the field of a longitudinal wave and in a transverse magnetic field is studied. The characteristics of such spontaneous radiation are obtained, and the influence of collective effects on the radiation is analyzed. The application of the findings to the theory of free electron lasers is discussed. 8 references.

1986-01-01

221

SEER Treatment Field Names, Edition Numbers, NAACCR Data Item Name,  

Science.gov (United States)

In addition, for breast cancer, a fifth field, Reconstruction--First Course is recorded. V.02.E Reconstruction--First Course (breast only) 1 digit These codes for these fields are included as Appendix C of this manual.

222

Receptive Field Remodeling Induced by Skin Stimulation in Cerebellar Neurons in vivo  

UK PubMed Central (United Kingdom)

The receptive field of a neuron reflects its function. For example, for parallel fiber (PF) inputs in C3 zone the cerebellar cortex, the excitatory and inhibitory receptive fields of a Purkinje cell...Full Text Available

223

Pulmonary structure and function in adult dairy cows with an expanded lung field.  

UK PubMed Central (United Kingdom)

Pulmonary function tests were performed on seven adult dairy cows with an expanded lung field (ExLF) and the results were compared to the values from seven cows with normal lung fields. The cows with...Full Text Available

1991-01-01

224

Energy-momentum tensor of a spinor field in the mixed universe cosmological model  

International Nuclear Information System (INIS)

The energy-momentum tensor of a massless spinor field is constructed and studied based on the previously proposed interpretation of quantum effects of such a field in the anisotropic metric of Bianchi type IX. The characteristic properties of the energy-momentum tensor in the mixed universe model are discussed.

225

Non-commutative space and Chan-Paton algebra in open string field algebra  

Energy Technology Data Exchange (ETDEWEB)

There are several equivalent descriptions for constant B-field background of open string. The background can be interpreted as constant B-field as well as constant gauge field strength or infinitely many D-branes with non-commuting Chan-Paton matrices. In this article, the equivalence of these open string theories is studied in Witten's cubic open string field theory. Through the map between these equivalent descriptions, both algebra of non-commutative coordinates as well as Chan-Paton matrix algebra are identified with subalgebras of open string field algebra. (author)

2002-09-23

226

Dual-field rotational (DFR) technique for total-skin electron-beam therapy (TSEBT)  

Energy Technology Data Exchange (ETDEWEB)

Comparison of dosimetry measured in a noncylindrical Rando-Alderson phantom by two-field, four-field, and six-field total-skin electron-beam therapy (TSEBT) techniques with our dual-field rotational (DFR) technique reveals a superior dosimetry for the latter. Our technique of dual-field rotational DFR-TSEBT is described in detail, and its advantages and indications for the primary management of cutaneous T-cell lymphoma (CTCL) and Kaposi's sarcoma (KS) are discussed.

1987-08-01

227

Topological field theories and duality  

Energy Technology Data Exchange (ETDEWEB)

Topologically non trivial effects appearing in the discussion of duality transformations in higher genus manifold are discussed in a simple example, and their relation with the properties of Topological Field Theories is established. (author). 16 refs.

1996-05-01

228

Symptoms of the musculoskeletal system and exposure to magnetic fields in an aluminium plant.  

UK PubMed Central (United Kingdom)

OBJECTIVE--The study was performed to examine the influence of the exposure to magnetic fields in the potrooms of an electrolysis plant on the occurrence of musculoskeletal symptoms among the employees....Full Text Available

1995-08-01

229

SAFETY--Water Resources Division National Pollutant Discharge...  

Science.gov (United States)

Provisions (a) NPDES field personnel shall be currently trained and certified in CPR and basic first-aid procedures. (b) NPDES field personnel shall be aware of the...

2011-09-24

230

Overview of estimations of natural gas in small fields  

International Nuclear Information System (INIS)

An overview is given the expected amount of natural gas that can be produced from small gas fields in the Netherlands in the next 20 years.

2005-01-01

231

Mesodynamics in the SARS nucleocapsid measured by NMR field cycling  

Energy Technology Data Exchange (ETDEWEB)

Protein motions on all timescales faster than molecular tumbling are encoded in the spectral density. The dissection of complex protein dynamics is typically performed using relaxation rates determined at high and ultra-high field. Here we expand this range of the spectral density to low fields through field cycling using the nucleocapsid protein of the SARS coronavirus as a model system. The field-cycling approach enables site-specific measurements of R{sub 1} at low fields with the sensitivity and resolution of a high-field magnet. These data, together with high-field relaxation and heteronuclear NOE, provide evidence for correlated rigid-body motions of the entire {beta}-hairpin, and corresponding motions of adjacent loops with a time constant of 0.8 ns (mesodynamics). MD simulations substantiate these findings and provide direct ...

2009-09-15

233

Field studies among diverse biomes demonstrate that nitrogen ...  

Science.gov (United States)

Field studies among diverse biomes demonstrate that nitrogen concentration (% N) at leaf- and canopy-scales is strongly related to carbon uptake and cycling ...

234

Estimating Field Volatility of Soil Fumigants Using CHAIN_2D: Mitigation Methods and Comparison Against Chloropicrin and 1,3-Dichloropropene Field Observations  

British Library Electronic Table of Contents (United Kingdom)

Academic, government, and industrial field researchers have generated a significant database of field studies of the volatility of soil applied fumigants. However, limited work exists in validating physical models against field volatility data sets and fully exploring the volatility parametric response surface. Field studies quantifying atmospheric flux for soil fumigants 1,3-dichloropropene and chloropicrin are validated against the United States Department of Agriculture (USDA Salinity Laboratory) soil physics model CHAIN_2D that was modified specifically for agronomic uses of soil fumigants. Comparison between model predictions and field observations for six unique field trials in five different states indicate that CHAIN_2D effectively captures the magnitude and duration of fumigant em...

2010-01-01

235

Electromagnetic fields and public health.  

UK PubMed Central (United Kingdom)

A review of the literature is provided for the topic of health-related research and power frequency electromagnetic fields. Minimal evidence for concern is present on the basis of animal and plant research....Full Text Available

1987-11-01

237

Development of High Field Dipole and High Current Pulse Power Supply for Compact Proton Synchrotron  

CERN Document Server

Development of High Field Dipole and High Current Pulse Power Supply for Compact Proton Synchrotron

2003-01-01

238

Cohomology of the Virasoro algebra with coefficients in string fields  

International Nuclear Information System (INIS)

The first cohomology of the Virasoro algebra with coefficients in string fields are investigated. The relation between them and the Nambu-Goto action for a closed string is established. (orig.).

1990-01-01

239

APOD: 2009 May 26 - Whirlpool Galaxy Deep Field  

Science.gov (United States)

Clicking on the picture will download the highest resolution version available. Whirlpool Galaxy Deep Field Credit & Copyright: Jon Christensen Explanation: Follow the handle...

2011-10-07

240

Photophysical properties of new psoralen derivatives: psoralens linked to adenine through polymethylene chains  

International Nuclear Information System (INIS)

The model compounds, 8-methoxypsoralen-CH_2O(CH_2)_n-adenine (MOPCH_2OC_nAd, n=2,3,5,6,8, and 10) in which 5 position of 8-methoxypsoralen (8-MOP) is linked by various lengths of polymethylene bridge to N"9 of adenine. UV absorption spectra are identical with the sum of MOPCH_2OC3 and adenine absorption spectra. Solvent effect on the UV absorption and fluorescence emission spectra indicate that the lowest excited singlet state is the (#pi##->##pi#"*) state. The spectral characteristics of the fluorescence of MOPCH_2OC_nAd are strongly dependent upon the nature of the solvents. The fluorescence emission spectra in aprotic solvents are broad and structrueless due to the excimer formation through the folded conformation accelerated by hydrophobic #pi#-#pi# stacking interaction. Increasing polarity of the protic solvents leads to higher population of unfolded conformation stabilized through favorable solvation and H-bonding, and consequently to ...

2002-10-01

241

Enzymatic synthesis and carbon-13 nuclear magnetic resonance conformational studies of disaccharides containing. beta. -D-galactopyranosyl and. beta. -D-(1-/sup 13/C)Galactopyranosyl residues  

Energy Technology Data Exchange (ETDEWEB)

Partially purified UDPgalactosyltransferase (EC 2.4.1.22) from bovine milk has been used to synthesize millimolar amounts of compounds such as Gal..beta..(1..-->..4)Glc, Gal..beta..(1..-->..4)GlcNAc-..beta..-hexanolamine, and Gal..beta..(1..-->..4)-GlcNAc..beta..(1..-->..4)GlcNAc. The same method has been used to prepare similar compounds containing /sup 13/C-enriched galactopyranosyl moieties. Gal..beta..(1..-->..4)GlcNAc-..beta..-hexanolamine was also synthesized in a solid-phase system in which the GlcNAc-..beta..-hexanolamine glycoside was covalently linked to agarose beads. At pH 7.0 and at 1 to 5 mM Mn/sup 2 + +/ the yields of the galactosyl saccharides are greater than 90% by using 10% excess of UDPGal donor. The use of a 90% enriched (1-/sup 13/C)galactosyl residue allowed the determination of the most abundant conformer about the galactopyranosyl-glycoside linkage by analysis of the carbon-carbon coupling constants from Cl to Gal to the ...

1980-02-05

242

Concurrent and adjuvant docetaxel with three-dimensional conformal radiation therapy plus androgen deprivation for high-risk prostate cancer: Preliminary results of a multicentre phase II trial  

International Nuclear Information System (INIS)

Background and purpose: We evaluate the feasibility of concomitant and adjuvant docetaxel combined with three-dimensional conformal radiotherapy (3D-CRT) and androgen deprivation in high-risk prostate carcinomas. Methods: Fifty men with high-risk localized prostate cancer (16), locally advanced (28) or very high-risk prostate cancer (6) were included. Seventy Gy were delivered on prostate and seminal vesicles in 35 fractions, concurrently with weekly docetaxel (20 mg/m"2). Three weeks after the completion of 3D-CRT, docetaxel was given for 3 cycles (60 mg/m"2), every 3 weeks. Patients had to receive LHRH agonist during 3 years. Results: The intent to treat analysis shows that four patients out of 15 stopped prematurely the chemotherapy due to grade 3-4 acute toxicity. In the per protocol analysis, 46 patients completed a full-dose chemoradiation regimen representing 413 cycles: five patients experienced a grade 3 toxicity, and 15 patients experienced a grade 2 ...

2010-11-01

243

Antihuman growth hormone (GH) antibodies cross-react with the GH-like factor from plerocercoids of the tapeworm Spirometra mansonoides.  

Science.gov (United States)

A factor produced by the plerocercoid stage of S. mansonoides mimics some, but not all, of the actions reported for hGH. The biological actions of plerocercoid growth factor (PGF) suggest structural similarity to human GH (hGH). Plerocercoid membranes were solubilized, and PGF was purified more than 1000-fold by hGH receptor affinity chromatography. The ability of purified PGF to displace [125I]hGH from monoclonal antibodies specific for four distinct nonoverlapping antigenic determinants of hGH and from an anti-hGH polyclonal antibody was tested in liquid phase RIA. All of the hGH antibodies cross-reacted with PGF, with potencies ranging from more than 60% to less than 1% that of the hGH standard. Of the four major epitopes of hGH defined by the monoclonal antibodies used in this study, only one is not represented to a significant extent in PGF. The epitope of hGH that is only marginally present in PGF is highly conformationally dependent, and a minor difference ...

1987-11-01

244

An iterative filtered backprojection inverse treatment planning algorithm for tomotherapy  

International Nuclear Information System (INIS)

Purpose: An inverse treatment planning algorithm for tomotherapy is described. Methods and Materials: The algorithm iteratively computes a set of nonnegative beam intensity profiles that minimizes the least-squares residual dose defined in the target and selected normal tissue regions of interest. At each iteration the residual dose distribution is transformed into a set of residual beam profiles using an inversion method derived from filtered backprojection image reconstruction theory. These 'residual' profiles are used to correct the current beam profile estimates resulting in new profile estimates. Adaptive filtering is incorporated into the inversion model so that the gross structure of the dose distribution is optimized during initial iterations of the algorithm, and the fine structure corresponding to edges is obtained at later iterations. A three dimensional, kernel based, convolution/superposition dose model is used to compute dose during each iteration. Results: Two clinically ...

1995-07-15

248

Reduction of four-vector field in terms of standard helicity representation of inhomogeneous Lorentz group for imaginary mass system  

Energy Technology Data Exchange (ETDEWEB)

The reduction of four-vector and electromagnetic fields produced by spin-1 tachyons has been derived in terms of standard helicity representations of inhomogeneous Lorentz group, and the conditions for these superluminal electromagnetic fields to satisfy the Maxwell's field equations have been derived. 16 refs.

1981-11-01

250

Probing Neutron Star Evolution with Gamma Rays  

Science.gov (United States)

The research sponsored by this grant was conducted in two fields of high-energy astrophysics:

1996-01-01

253

Observational constraints in scalar tensor theory with tachyonic potential  

CERN Document Server

We study the dynamics of the scalar tensor cosmological model in the presence of tachyon field. In an alternative approach, in two exponential and power law form of the scalar field functions in the model, field equations are solved by simultaneously best fitting the model parameters with the most recent observational data. This approach gives us an observationally verified interpretation of the dynamics of the universe. We then discuss the best fitted of equation of state parameter, the statefinder parameters and the reconstructed scalar field in the model.

2011-01-01

257

Magnetic phase transition in UPd_2Si_2  

International Nuclear Information System (INIS)

... fields magnetic moments neel temperature neutron diffraction order-disorder

259

Influence of rotation and magnetic field on the minimum mass of a main-sequence star  

Energy Technology Data Exchange (ETDEWEB)

The influence of rigid-body and differential rotation and of a fine-scale chaotic magnetic field and a poloidal magnetic field on the minimum mass of a main-sequence star is investigated. It is shown that rotation and a magnetic field with an energy equal to 10--20% of the star's gravitational energy increase the minimum mass of a main-sequence star by 1.5--2 times.

1980-11-01

261

ISR site  

CERN Document Server

A last look at the green field, in the triangular wedge of land stray radiation near the CERN accelerators.

1965-01-01

272

Covariant open bosonic string field theory including the endpoint and middlepoint interaction  

Energy Technology Data Exchange (ETDEWEB)

Extending the usual endpoint and midpoint interactions, we introduce numerous kinds of interactions, labelled by a parameter lambda and obtain a non-commutative and associative string field algebra by adding up all interactions. With this algebra we develop a covariant open bosonic string field theory, which reduces to Witten's open bosonic string field theory under a special string length choice.

1988-07-01

274

CRC handbook of biological effects of electromagnetic fields  

Energy Technology Data Exchange (ETDEWEB)

This book presents the current knowledge about the effects of electromagnetic fields on living matter. The three-part format covers dielectric permittivity and electrical conductivity of biological materials; effects of direct current and low frequency fields; and effects of radio frequency (including microwave) fields. The parts are designed to be consulted independently or in sequence, depending upon the needs of the reader. Useful appendixes on measurement units and safety standards are also included.

1986-01-01

277

Alterations in Adenylate Kinase Activity in Human PBMCs after In Vitro Exposure to Electromagnetic Field: Comparison between Extremely Low Frequency Electromagnetic Field (ELF) and Therapeutic Application of a Musically Modulated Electromagnetic Field (TAMMEF)  

UK PubMed Central (United Kingdom)

This study investigated the effects of electromagnetic fields on enzymes involved in purine metabolism in human peripheral blood mononuclear cells in vitro. Cells were obtained from 20 volunteers. We...Full Text Available

2009-01-01

278

Radiative corrections to the atomic levels in a periodic electromagnetic field  

Energy Technology Data Exchange (ETDEWEB)

The influence of a periodic electromagnetic field on the radiative corrections to the atomic energy levels is studied for the case of ''strong fields'' for which the interaction between the atom and field is of the order or greater than the radiative effects. The analysis is carried out on the basis of the Schwinger-Dirac equation for the propagation function of a bound electron in the field and on the basis of the density matrix in the Furry representation. It is shown that in the strong field approximation the radiative shifts and widths are manifest as radiative corrections to the quasi-energies. In super-high resolution experiments intensity effects in the radiative corrections to the atomic levels are obtained in the case of single-photon resonance. Some multiphoton processes are condidered by taking into account the effect of the ...

1982-12-01

279

Evaluation of Reports on Environmental Measurements of Electromagnetic Fields Generated by High Voltage Transmission Lines and Substations  

International Nuclear Information System (INIS)

This paper presents some situations, in which measurements of electromagnetic fields generated by transmission lines and substations should be performed. The range of measurements may differ, but maximum values of electric and magnetic fields and flux density must be identified in all situations. The area with electric field exceeding 1 kV/m should be identified as well. The author also presents basic requirements to be met by the measurement technique. These requirements are specified according to the national standard. Special attention should be paid to the identification of the spatial distribution of electric field and flux density generated in the vicinity of high voltage transmission lines. To verify the measurement results, it is necessary to calculate the distribution of both aforesaid field components. For environmental protection purposes, it is also proposed that the ...

2007-01-01

280

The origin of large scale magnetic fields  

CERN Document Server

Magnetic fields correlated on several kiloparsec scales are seen in spiral galaxies. Their origin could be due to the winding up of a primordial cosmological field or due to amplification of a small seed field by a turbulent galactic dynamo. Both options have difficulties: There is no known battery mechanism for producing the required primordial field. Equally the turbulent dynamo may self destruct before being able to produce the large scale field, due to excess generation of small scale power. The current status of these difficulties is discussed. The resolution could depend on the nature of the saturated field produced by the small scale dynamo. We argue that the small scale fields do not fill most of the volume of the fluid and instead concentrate into intermittent ropes, with their peak value of order equipartition ...

1996-01-01

281

Three-dimensional numerical simulation of temperature field and helium flow field in ITER China TBM  

International Nuclear Information System (INIS)

Three dimensional temperature field and helium flow field of TBM are simulated using the general purpose computational fluid dynamics (CFD) code FLUENT. The temperature distribution of Be Armor, Be Pebble Bed, Li_4SiO_4 Pebble Bed, Structure Material of TBM, and helium flow field in the cooling pipe are presented. The research indicates that the work temperature of each material is under the material temperature allowed except some places where high temperature should be excluded in the design. The results will provide references for further optimized thermal hydraulic design of ITER China TBM. (authors)

2006-02-01

282

Plasma Dynamics in the Vicinity of the Local Plasma resonance Point Excited by Pumping Electric Field or Modulated Electron Beam  

International Nuclear Information System (INIS)

Excitation of the HF electric field in the local plasma resonance region (LPRR) of inhomogeneous plasma by pumping electric field or modulated electron beam results to appearance of the ponderomotive force that presses plasma out of this region. Density cavity is formed in the LPRR due to this field. Further dynamics in this region depends on the plasma properties. For plasma with hot electrons ion-acoustic pulses run away from the cavity. at the local density maximum the new peak of electric field is excited. It results to the formation of new density cavity, etc. For isothermal plasma the density jump is formed.

2006-01-01

283

Evaluation of optimum sheath electric field for selective production of metallic carbon nanotubes  

International Nuclear Information System (INIS)

We estimate the optimum electric field at the sheath edge and the minimum interval among the nanotubes to promote the growth of armchair-type nanotubes (metallic character) as a function of the tube length. On the basis of the electric charge distribution in a nanotube and the optimum electric filed E*_1 at the tip of a nanotube evaluated using the Hueckel-Poisson method, we calculate the structure of the electric field lines outside a nanotube in the sheath region. As the tube length increases, the E*_1 decreases. To maintain the chemical activity at the tip, the sheath electric field must be decreased. We show the decreasing rate of the sheath field to the tube length.

2006-03-21

284

Electric field exposure from electric blankets  

Energy Technology Data Exchange (ETDEWEB)

Comparisons of the 60 Hz electric field exposures associated with high voltage transmission lines to those associated with common household sources can provide an important input to regulatory decisions that involve transmission line fields. Electric blankets are of interest in this context because the exposures they produce are among the most intense and prolonged of any of the household sources of 60 Hz electric field exposure. This paper presents a theoretical analysis of the body surface fields induced by electric blankets. Electric blanket exposure intensities are compared to those associated with transmission lines.

1987-04-01

285

Domain wall pining in a jointed ferromagnetic nano-wire  

Energy Technology Data Exchange (ETDEWEB)

The magnetoresistance in an FeNi submicron-structure comprising two wires of 80 and 200 nm in width connected in series was measured at 77 K. When the external magnetic field was applied parallel to the wire axis, two switching fields corresponding to the distinct coercive force of the two wires were observed. When the external magnetic field was applied at an angle of {theta}>30 deg. to the wire axis one switching field was observed, indicating simultaneous magnetization reversal in both wires. This indicates that the domain-wall trapping around the joint can be controlled systematically in terms of the direction of the external magnetic field.

2004-05-01

286

Discrete vacuum superselection rule in Wightman theory with essentially self-adjoint field operators  

Energy Technology Data Exchange (ETDEWEB)

The main results of earlier work by the author, Sushko, and Khoruzhii describing the algebraic structure of quantum-field systems with (discrete) vacuum superselection rules are generalized to the large class of Wightman theories with essentially self-adjoint field operators (a very strong restriction was imposed on the theory, namely, that the polynomial Op algebra of the Wightman fields /rho/ belongs to the class II, i.e., /rho/ /sub s'/ =/rho/ /sub w'/). It is also shown that the field Op algebra of a Wightman theory with discrete vaccum superselection rule possesses a class II extension.

1986-07-01

287

Bianchi type IX cosmological models with homogeneous spinor fields  

Energy Technology Data Exchange (ETDEWEB)

The diagonal and symmetric Bianchi type IX models are coupled to a homogeneous spinor field. An action for the combined fields is constructed, where the orthonormal basis used is given explicitly in terms of the metric. This allows one to vary the action with respect to the metric and the spinor fields only. Next, a Hamiltonian formulation is given, and a qualitative solution for the problem is presented. We also show that the k = +1 FRW (Friedmann--Robertson--Walker) model is not compatible with a homogeneous spinor field, while the more complicated models are.

1981-03-01

288

Bianchi type IX cosmological models with homogeneous spinor fields  

International Nuclear Information System (INIS)

The diagonal and symmetric Bianchi type IX models are coupled to a homogeneous spinor field. An action for the combined fields is constructed, where the orthonormal basis used is given explicitly in terms of the metric. This allows one to vary the action with respect to the metric and the spinor fields only. Next, a Hamiltonian formulation is given, and a qualitative solution for the problem is presented. We also show that the k = +1 FRW (Friedmann--Robertson--Walker) model is not compatible with a homogeneous spinor field, while the more complicated models are.

289

Electric-field-induced deformation of biological cells  

Energy Technology Data Exchange (ETDEWEB)

The cell is modeled as an ellipsoid with shell and the surface stress distribution calculated by means of the Maxwell Stress Tensor. The cell membrane is treated as incompressible material having both bending and shear energies of deformation. Employing the principle of virtual work, cell volume (and hence shape) is computed as a function of the external field strength and orientation with respect to the field. The following results were obtained: (1) The surface stresses that develop or the cell membrane are distributed having both normal and tangential components that act together to produce a rounding of the cell. (2) If the tangential component of the stress is ignored, then higher field strengths are needed to produce similar deformation (shape change) of cells. (3) The threshold value of the applied field, i.e, the field strength at which the volume (shape) of the cell changes ...

1989-01-01

290

X-ray scattering signatures of {beta}-thalassemia  

Energy Technology Data Exchange (ETDEWEB)

X-ray scattering from lyophilized proteins or protein-rich samples is characterized by the presence of two characteristic broad peaks at scattering angles equivalent to momentum transfer values of 0.27 and 0.6 nm{sup -1}, respectively. These peaks arise from the interference of coherently scattered photons. Once the conformation of a protein is changed, these two peaks reflect such change with considerable sensitivity. The present work examines the possibility of characterizing the most common cause of hemolytic anaemia in Egypt and many Mediterranean countries; {beta}-thalassemia, from its X-ray scattering profile. This disease emerges from a genetic defect causing reduced rate in the synthesis of one of the globin chains that make up hemoglobin. As a result, structurally abnormal hemoglobin molecules are formed. In order to detect such molecular disorder, hemoglobin samples of {beta}-thalassemia patients are collected, lyophilized and measured using a ...

2009-08-11

291

The structure of myostatin:follistatin 288: insights into receptor utilization and heparin binding  

Science.gov (United States)

Myostatin is a member of the transforming growth factor-{beta} (TGF-{beta}) family and a strong negative regulator of muscle growth. Here, we present the crystal structure of myostatin in complex with the antagonist follistatin 288 (Fst288). We find that the prehelix region of myostatin very closely resembles that of TGF-{beta} class members and that this region alone can be swapped into activin A to confer signalling through the non-canonical type I receptor Alk5. Furthermore, the N-terminal domain of Fst288 undergoes conformational rearrangements to bind myostatin and likely acts as a site of specificity for the antagonist. In addition, a unique continuous electropositive surface is created when myostatin binds Fst288, which significantly increases the affinity for heparin. This translates into stronger interactions with the cell surface and enhanced myostatin degradation in the presence of either Fst288 or Fst315. Overall, we have identified several ...

2009-09-29

292

The reaction of hydroxylamine with bacteriorhodopsin studied with mutants that have altered photocycles: Selective reactivity of different photointermediates  

Energy Technology Data Exchange (ETDEWEB)

The reaction of the retinylidene Schiff base in bacteriorhodopsin (bR) to the water-soluble reagent hydroxylamine is enhanced by greater than 2 orders of magnitude under illumination. We have used this reaction as a probe for changes in Schiff base reactivity during the photocycle of wild-type bR and mutants defective in proton transport. We report here that under illumination at pH 6, the D85N mutant has a 20-fold lower rate and the D212N mutant has a greater than 4-fold higher rate for the light-dependent reaction with hydroxylamine compared with wild-type bR. In contrast, the reactivities of wild-type bR and the D96N and T46V mutants are similar. It has been previously shown that the D96N and T46V replacements have no significant effect on the kinetics of M formation but have dramatic effects on rate of the decay of M. We therefore conclude that the hydroxylamine reaction occurs before formation of the M intermediate. Most likely it occurs at the L stage of the cycle and reflects ...

1991-03-15

293

The complete mitochondrial genome of Atelura formicaria (Hexapoda: Zygentoma) and the phylogenetic relationships of basal insects.  

Science.gov (United States)

In this study, the complete sequence of the mitochondrial DNA (mtDNA) of Atelura formicaria (Hexapoda: Zygentoma) is described. The molecule is 15.205 bp in length and it is the third complete mt genome sequenced from the Zygentoma. The genome organization conforms with the putative ancestral insect gene arrangement. All protein coding genes use standard initiation codons (methionine and isoleucine). The exception is nad4 that starts with GTG, a codon used for this purpose in other insect species. A peculiar strand skew bias is observed, given that the PCGs encoded on the J-strand contain more thymines than adenines and more cytosines than guanines. This trend in nucleotide composition has been observed also in the "firebrat" Thermobia domestica (Zygentoma, Lepismatidae), but differs from that of the majority of hexapod species, including Tricholepidion gertschi (Zygentoma, Lepidotrichidae), where adenines and cytosines outnumber thymines and guanines. The presence ...

2009-03-11

294

Study on the variations of molecular structures of some biomolecules induced by free electron laser using FTIR spectroscopy  

International Nuclear Information System (INIS)

In this study, free electron laser (FEL) with selective wavelength was used to induce structure changes of biomolecules, which were characterized by FTIR spectroscopy. For understanding of the interactions between FEL and biomolecules as well as biological tissues, the biomolecules investigated are ATP, ADP, AMP, t-RNA, D-ribose and the complex of SmCl_3-D-ribose. Their FTIR spectra before and after irradiation of FEL show molecular structure variations of the samples after irradiation of FEL, especially the rearrangement of their hydrogen bond networks. Along with the various irradiation wavelengths, irradiation time and molecular structures, the changes after irradiation are different for these molecules. In the FTIR spectra after irradiation, the phenomenon that the bands split into several peaks indicates the existence of several structures, conformations and configurations, which may be prompted by multiple photons process induced by FEL. After irradiation, ...

2007-05-01

295

Structure-retention correlations of hydrocarbons in gas-liquid and gas-solid chromatography. Cycloalkenes and cycloalkadienes  

Energy Technology Data Exchange (ETDEWEB)

The retention indices of cycloalkenes and cycloalkadienes with C/sub 6/-C/sub 13/ rings are determined by gas-liquid chromatography (GLC) on glass capillary columns coated with OV-1 and Ucon LB 550X and by gas-solid chromatrography (GSC) on a microcolumn packed with uncoated graphitized thermal carbon black (GTCB). Structure-retention correlations are derived on using index differences such as H/sup OV/, H/sup GTCB/ and ..delta..I values, considering the differences in the stereochemistry of these compounds. It is shown that the combined application of index increments obtained in GLC and GSC provides more detaled structure informations. The value of the retention index units agree with the most stable conformations of the alicyclic compounds. The high value for the energy equivalent to an index unit (..delta..G/sub I.U./ = 4.18 kJ/mol) confirms that graphitized thermal carbon black causes much stronger dispersive interactions than any nonpolar liquid phase.

1987-08-01

296

Structural analysis of experimental carbide fueled driver assmbly flow duct for testing in the FFTF  

International Nuclear Information System (INIS)

Mixed carbide fueled driver assembly experiments will be tested in FFTF fuel driver positions as part of the National Advanced Fuel Program. The design of the experiment flow ducts must assure conformance to FFTF functional requirements in addition to service as a test vehicle for the carbide fuel irradiations. Test goals of damage fluence burnup, and fluence to burnup ratio exceed those of the standard oxide fueled drivers. As a consequence, the 20% cold worked type 316 stainless steel material of construction will experience significant irradiation induced creep and swelling. Additionally, the flow duct design must withstand the enhanced thermal transients produced by the action of carbide fuel during reactor scrams. A major FFTF functional requirement is that adjacent flow ducts do not touch each other except at the load pads. This requires a realistic analysis of the creep and swelling deformation of the flow duct during an experiment lifetime. Flow duct ...

297

Spectroscopic studies on the interaction of the antibiotic lasalocid A (x-537a) with technetium (V) ions in methanol  

International Nuclear Information System (INIS)

In the present study, the authors examine the interactions of pentavalent technetium ions (TcO/sup 3+/) with the basic form of the lasalocid A in pure methanol solvent and in methanol-water mixtures. There are a number of reasons for such a study. First, the interactions of technetium ions with biologically important compounds are of considerable importance owing to the widespread use of /sup 99m/Tc in diagnostic radio-imaging. Second, lasalocid A is known to transport metal ions across phospholipid bilayer membranes and between the aqueous cores of phospholipid inverse micelles. Third, lasalocid A is known to bind and solubilize metal ions in bulk organic liquid phases. Fourth, the conformation adopted by lasalocid A on interaction with TcO/sup 3+/ appears to be different than those found in most other cases and circumstances. Fifth, it may also be possible to use the competition of TcO/sup 3+/ with other, physiologically relevant cations (Na/sup +/, K/sup +/, ...

298

Silica Polyamine Composites: New Supramolecular Materials for Cation and Anion Recovery and Remediation  

Energy Technology Data Exchange (ETDEWEB)

The surface coverage of amorphous silica gels used in the synthesis of silica polyamine composites has been investigated by 29Si NMR. By diluting the polyamine anchor silane, chloropropyl trichlorosilane, with methyl trichlorosilane it was found that surface coverage could be markedly improved for a range of amine polymers after grafting to the silica surface. The commensurate decrease in the number of anchor points and increase in the number of free amines results in an increase in metal capacity and/or an improvement in capture kinetics. Solid state CPMAS-13C NMR has been employed to investigate the structure and metal ion binding of a series of these composite materials. It is reported that the highly branched polymer, poly(ethyleneimine) (PEI) exhibits much broader 13C NMR resonances than the linear polymers poly(allylamine) (PAA) and poly(vinylamine) (PVA). These results are understood in terms of the low energy conformations calculated from molecular modeling ...

2006-03-01

299

Short-term regulation of muscarinic acetylcholine receptors: An assessment utilizing mouse brain and mouse neuroblastoma cells  

Energy Technology Data Exchange (ETDEWEB)

The effects of muscarinic agonists and diisopropylfluorophosphate (DFP) on muscarinic receptor density and muscarinic receptor-mediated responses was assessed in mouse brain and mouse neuroblastoma cells (clone N1E-115). Utilizing the antagonist ({sup 3}H)quinuclidinyl benzilate (({sup 3}H)QNB), there was no difference in the maximal binding capacity (B{sub max}) or equilibrium dissociation constant (K{sub d}) between untreated and 24 hour DFP-treated mice. However, one administration of DFP produced a 24% and 33% decrease in B{sub max} measured by ({sup 3}H)N-methylscopolamine (({sup 3}H)NMS) after 18 and 24 hours which was rapidly reversible within 36 hours after DFP treatment. The loss of ({sup 3}H)NMS binding sites following acute DFP treatment was not accompanied by a change in a particular muscarinic receptor binding conformation. Furthermore, the magnitude of muscarinic receptor-mediated phosphoinositide hydrolysis was unchanged following short-term DFP ...

1988-01-01

300

Recognition and Detoxification of the Insecticide DDT by Drosophila melanogaster Glutathione S-Transferase D1  

Energy Technology Data Exchange (ETDEWEB)

GSTD1 is one of several insect glutathione S-transferases capable of metabolizing the insecticide DDT. Here we use crystallography and NMR to elucidate the binding of DDT and glutathione to GSTD1. The crystal structure of Drosophila melanogaster GSTD1 has been determined to 1.1 {angstrom} resolution, which reveals that the enzyme adopts the canonical GST fold but with a partially occluded active site caused by the packing of a C-terminal helix against one wall of the binding site for substrates. This helix would need to unwind or be displaced to enable catalysis. When the C-terminal helix is removed from the model of the crystal structure, DDT can be computationally docked into the active site in an orientation favoring catalysis. Two-dimensional {sup 1}H,{sup 15}N heteronuclear single-quantum coherence NMR experiments of GSTD1 indicate that conformational changes occur upon glutathione and DDT binding and the residues that broaden upon DDT binding support the ...

2010-06-14

301

Predicting Knot and Catenane Type of Products of Site-specific Recombination on Twist Knot Substrates  

CERN Document Server

Site-specific recombination is an important cellular process that yields a variety of knotted and catenated DNA products on supercoiled circular DNA. Twist knots are some of the most common conformations of these products. They are also one of the simplest families of knots and catenanes. Yet, our systematic understanding of their implication in DNA and important cellular processes like site-specific recombination is very limited. Here we present a topological model of site-specific recombination characterising all possible products of site-specific recombination on twist knot substrates, extending previous work of Buck and Flapan. We illustrate how to use our model to examine previously uncharacterized experimental data. We show how our model can help determine the sequence of products in multiple rounds of processive recombination and distinguish between products of processive and distributive recombination. Companion paper (arXiv:1007.2115v1 math.GT) provides ...

2010-01-01

302

Precise characterisation of nanochannels in track etched membranes by SAXS and SANS  

Energy Technology Data Exchange (ETDEWEB)

Poster session: Abstract is full text. Track membranes are thin polymer foils irradiated by heavy ions. The defects created by the heavy ions are located along the ions trajectory, the track. It is possible to open channels by etching with a chemical agent. These channels are very uniform. Small Angle Scattering (of X rays and neutrons) give global information about the characteristics of the channel shape. As the nanochannels are strictly parallel, an excellent sample orientation is required to obtain interpretable spectra. Then shoulders due to the oscillations of the Bessel function (radial part of the channel shape Fourier transform) are easily seen in the scattered intensity in the PXY data treatment software of SAS spectra allow to determine the channel diameter with its dispersion law, to demonstrate the existence of a wall thickness with a linearly varying density, and to assess the roughness. PXY can also detect non cylindric shapes like single or double cones or spindles. ...

2003-05-01

303

Photovoltaic industry manufacturing technology. Final report  

Energy Technology Data Exchange (ETDEWEB)

This report contains the results of the Photovoltaic (PV) Industry Manufacturing Technology Assessment performed by the Automation and Robotics Research Institute (ARRI) of the University of Texas at Arlington for the National Renewable Energy laboratory. ARRI surveyed eleven companies to determine their state-of-manufacturing in the areas of engineering design, operations management, manufacturing technology, equipment maintenance, quality management, and plant conditions. Interviews with company personnel and plant tours at each of the facilities were conducted and the information compiled. The report is divided into two main segments. The first part of the report presents how the industry as a whole conforms to ``World Class`` manufacturing practices. Conclusions are drawn from the results of a survey as to the areas that the PV industry can improve on to become more competitive in the industry and World Class. Appendix A contains the questions asked in the ...

1998-08-01

304

Office of Inspector General audit report on the U.S. Department of Energy`s consolidated financial statements for fiscal year 1998  

Energy Technology Data Exchange (ETDEWEB)

The Department prepared the Fiscal Year 1998 Accountability Report to combine critical financial and program performance information in a single report. The Department`s consolidated financial statements and the related audit reports are included as major components of the Accountability Report. The Office of Inspector General audited the Department`s consolidated financial statements as of and for the years ended September 30, 1998 and 1997. In the opinion of the Office of Inspector General, except for the environmental liabilities lines items in Fiscal year 1998, these financial statements present fairly, in all material respects, the financial position of the Department as of September 30, 1998 and 1997, and its consolidated net cost, changes in net position, budgetary resources, financing activities, and custodial activities for the years then ended in conformity with Federal accounting standards. In accordance with Government Auditing Standards, the Office of ...

1999-02-01

305

Off-road compression-ignition engine emission regulations under the Canadian Environmental Protection Act 1999 : guidance document  

Energy Technology Data Exchange (ETDEWEB)

This guide explained the requirements for Off-Road Compression Ignition Engine Emission Regulations established under the Canadian Environmental Protection Act. The regulations are enforced by Environment Canada, which authorizes and monitors the use of the national emissions mark. The regulations prescribe standards for off-road engines that operate as reciprocating, internal combustion engines, other than those that operate under characteristics similar to the Otto combustion cycle and that use a spark plug or other sparking device. The regulations apply to engines that are typically diesel-fuelled and found in construction, mining, farming and forestry machines such as tractors, excavators and log skidders. Four different types of persons are potentially affected by the regulations: Canadian engine manufacturers; distributors of Canadian engines or machines containing Canadian engines; importers of engines or machines for the purpose of sale; and persons not in companies importing ...

2006-03-15

306

Off-road compression-ignition engine emission regulations under the Canadian Environmental Protection Act 1999 : guidance document  

International Nuclear Information System (INIS)

This guide explained the requirements for Off-Road Compression Ignition Engine Emission Regulations established under the Canadian Environmental Protection Act. The regulations are enforced by Environment Canada, which authorizes and monitors the use of the national emissions mark. The regulations prescribe standards for off-road engines that operate as reciprocating, internal combustion engines, other than those that operate under characteristics similar to the Otto combustion cycle and that use a spark plug or other sparking device. The regulations apply to engines that are typically diesel-fuelled and found in construction, mining, farming and forestry machines such as tractors, excavators and log skidders. Four different types of persons are potentially affected by the regulations: Canadian engine manufacturers; distributors of Canadian engines or machines containing Canadian engines; importers of engines or machines for the purpose of sale; and persons not in companies importing ...

1999-01-01

307

Observability of complex ghosts and tachyons  

International Nuclear Information System (INIS)

The complex ghost introduced previously by the present author is studied from a standpoint whether its effects are observable by experiments or not. According to the theory of complex ghost the scattering cross section of two real particles shows some particular properties. It has a kind of resonance peak at a certain energy which does not conform to the Breit-Wigner formula. It has also a peak for a certain energy transfer, if there exist tachyons. The tachyon is a kind of ghost and is allowed to exist in the theory. Using these properties the complex ghosts are expected to be detected by experiments. The recently observed resonance psi(3.1) is supposed to be the complex ghost of photon, since they have the same quantum numbers. If it is assumed, some properties of the resonance known by experiments are explained naturally to a certain extent. Along the same line it is not unnatural to expect that the photon is also accompanied by a tachyon as a ghost. An ...

308

NMR studies of Borrelia burgdorferi OspA, a 28 kDa protein containing a single-layer #beta#-sheet  

International Nuclear Information System (INIS)

The crystal structure of outer surface protein A (OspA) from Borrelia burgdorferi contains a single-layer #beta#-sheet connecting the N- and C-terminal globular domains. The central #beta#-sheet consists largely of polar amino acids and it is solvent-exposed on both faces, which so far appears to be unique among known protein structures. We have accomplished nearly complete backbone H, C and N and C";/H"#beta# assignments of OspA (28 kDa) using standard triple resonance techniques without perdeuteration. This was made possible by recording spectra at a high temperature (45 "oC ). The chemical shift index and "1"5N T_1/T_2 ratios show that both the secondary structure and the global conformation of OspA in solution are similar to the crystal structure, suggesting that the unique central #beta#-sheet is fairly rigid.

1998-05-01

309

Microlocal analysis of asymptotically hyperbolic and Kerr-de Sitter spaces  

CERN Document Server

In this paper we develop a general, systematic, microlocal framework for the Fredholm analysis of non-elliptic problems, including high energy (or semiclassical) estimates, which is stable under perturbations. This framework is relatively simple given modern microlocal analysis, and only takes a bit over a dozen pages after the statement of notation. It resides on a compact manifold without boundary, hence in the standard setting of microlocal analysis, including semiclassical analysis. The rest of the paper is devoted to applications. Many natural applications arise in the setting of non-Riemannian b-metrics in the context of Melrose's b-structures. These include asymptotically Minkowski metrics, asymptotically de Sitter-type metrics on a blow-up of the natural compactification and Kerr-de Sitter-type metrics. The simplest application, however, is to provide a new approach to analysis on Riemannian or Lorentzian (or indeed, possibly of other signature) conformally ...

2010-01-01

310

Maintenance implementation plan for the B Plant/WESF. Revision 4  

Energy Technology Data Exchange (ETDEWEB)

This Maintenance Implementation Plan (MIP) has been developed for maintenance functions associated with the B Plant/WESF (Waste Encapsulation Storage Facility) complex. The objective of this plan is to provide baseline information for establishing and identifying WHC conformance programs and policies applicable to implementation of DOE order 4330.4B guidelines. In addition, this maintenance plan identifies the actions necessary to develop a cost-effective and efficient maintenance program at B Plant/WESF. The B Plant WESF facility complex consists of three main facilities and several support structures located in the 200 East Area of the Hanford site. B Plant is a transition facility that is required to ensure safe storage and management of WESF (operating facility) cesium and strontium capsules. B Plant/WESF also contains substantial radiological inventory from previous campaigns. There are no production activities at B Plant, but several of its operating systems ...

1996-01-01

311

Limiting values of radionuclide intake and air concentration and dose conversion factors for inhalation, submersion, and ingestion: Federal guidance report No. 11  

Energy Technology Data Exchange (ETDEWEB)

Radiation protection programs for workers are based, in the United States, on a hierarchy of limitations stemming from Federal guidance approved by the President. This guidance, which consists of principles, policies, and numerical primary guides, is used by Federal agencies as the basis for developing and implementing their own regulatory standards. The primary guides are usually expressed in terms of limiting doses to workers. The protection of workers against taking radioactive materials into the body, however, is accomplished largely through the use of regulations based on derived guides expressed in terms of quantities or concentrations of radionuclides. The values of these derived guides are chosen so as to assure that workers in work environments that conform to them are unlikely to receive radiation doses that exceed the primary guides. The purpose of the present report is to set forth derived guides that are consistent with current Federal radiation ...

1988-09-01

312

Kinetics of complexing activation by the magnesium ion on green crab (Scylla serrata) alkaline phosphatase.  

Science.gov (United States)

As with mammalian enzymes, green crab (Scylla serrata) alkaline phosphatase can be activated by Mg2+ through a time-dependent course. The activation is mainly a Vmax effect. Tsou's method was used to study the kinetic course of activation. The results show that the enzyme was activated by a complexing scheme that had not been previously identified: the enzyme first reversibly and quickly binds Mg2+ and then undergoes a slow reversible course to activation, with a relatively high activation energy (78 +/- 4 kJ/mol) and a slow conformational change. The activation reaction is a single molecule reaction, and the apparent activation rate constant is independent of Mg2+ concentration if the concentration is sufficiently high. The microscopic rate constants of activation and the association constant were determined from the measurements. The proposed scheme may also be applied to the Mg2+ activation mechanism for mammalian enzyme, to explain why the activation rate is ...

2001-01-01

313

Interaction of bovine serum albumin with some novel PEG-containing diblock copolymers  

British Library Electronic Table of Contents (United Kingdom)

A comparative study on the interaction of different PEG-containing diblock copolymers including SA400, SA600, SA1500 and OA1500 (stearyl and oleyl esters of polyethylene glycol with 400, 600 and 1500 molecular weights, respectively) with bovine serum albumin (BSA) was carried out using isothermal titration calorimetry (ITC), attenuated total reflectance Fourier transform infrared (ATR-FTIR), circular dichroism (CD), and fluorescence spectroscopies. ITC data show that SA400, SA600, SA1500 and OA1500 bind to BSA, with association constants of (14.5, 3.16, 50.7 and 17.6)x103M-1, respectively. Results also show that the binding is enthalpically driven, disfavored by conformational entropy. Quantitative analysis of the FTIR absorbance spectra at amide Iprime (1600-1700cm-1) as well as far UV ci...

2008-01-01

314

Identification of three related human GRO genes encoding cytokine functions  

International Nuclear Information System (INIS)

The product of the human GRO gene is a cytokine with inflammatory and growth-regulatory properties; GRO is also called MGSA for melanoma growth-stimulatory activity. The authors have identified two additional genes, GRO#beta# and GRO#gamma#, that share 90% and 86% identity at the deduced amino acid level with the original GRO#alpha# isolate. One amino acid substitution of proline in GRO#alpha# by leucine in GRO#beta# and GRO#gamma# leads to a large predicted change in protein conformation. Significant differences also exist in the 3' untranslated region, including different numbers of ATTTA repeats associated with mRNA instability. A 122-base-pair region in the 3' region is conserved among the three GRO genes, and a part of it is also conserved in the Chinese hamster genome, suggesting a role in regulation. DNA hybridization with oligonucleotide probes and partial sequence analysis of the genomic clones confirm that the three forms are derived from related but ...

315

Highly specific antiserum for arginine vasopressin  

International Nuclear Information System (INIS)

A high sensitivity (titer 60-150,000) radioimmunoassay for arginine vasopressin (AVP) has been developed using synthetic AVP as antigen and standard. The specificity of the antiserum has been characterized in detail by measuring the relative binding affinities of 29 analogs and fragments of AVP. In general, single amino acid substitution or deletion in the AVP molecule caused a reduction in binding to the antiserum; binding was further impaired for analogs which had multiple substitutions. ''Ring'' and ''tail'' fragments of the neurohypophysial hormones did not bind to the antiserum, and the only analog which the antiserum could not differentiate from AVP was deamino-AVP. More specifically, the antiserum exhibited the following properties: position 1, no requirement for a position charge at "1/_2 Cys; positions 2 and 3, requirements for #pi#-#pi# interacting pair of aromatic side chains and for Tyr at position 2; position 4, requirement for Gln (>Thr > Val); position 8, ...

316

Groundwater surveillance plan for the Oak Ridge Reservation  

Energy Technology Data Exchange (ETDEWEB)

US Department of Energy (DOE) Order 5400.1 requires the preparation of environmental monitoring plans and implementation of environmental monitoring programs for all DOE facilities. The order identifies two distinct components of environmental monitoring, namely effluent monitoring and environmental surveillance. In general, effluent monitoring has the objectives of characterizing contaminants and demonstrating compliance with applicable standards and permit requirements, whereas environmental surveillance has the broader objective of monitoring the effects of DOE activities on on- and off-site environmental and natural resources. The purpose of this document is to support the Environmental Monitoring Plan for the Oak Ridge Reservation (ORR) by describing the groundwater component of the environmental surveillance program for the DOE facilities on the ORR. The distinctions between groundwater effluent monitoring and groundwater surveillance have been defined in the Martin Marietta ...

1994-07-01

317

First detection of lamella-gyroid-cylinder phase transition of neat polyethylene-poly(ethylene oxide) diblock copolymers on the basis of synchrotron WAXD/SAXS and infrared/Raman spectral measurements  

International Nuclear Information System (INIS)

The phase transition behaviour of polyethylene-b-poly(ethylene oxide) (PE-b-PEO) diblock copolymer with relatively short chain lengths has been studied on the basis of temperature dependent infrared and Raman spectral measurements and synchrotron WAXD/SAXS simultaneous measurements, from which the concrete structural changes were deduced successfully from the various levels of molecular chain conformation, chain packing mode and higher-order structure. The higher-order structure has been found to transform between lamella, perforated lamella, gyroid, cylinder and sphere structures. The inner structural changes occurring in the polyethylene and poly(ethylene oxide) parts have been related with these morphological changes. The morphological transition from lamella to gyroid occurs with keeping the crystalline state of polyethylene parts. This apparently curious transition can be interpreted reasonably by assuming the thermally-activated chain motion in the crystal ...

2009-08-01

318

Experimental determination of the dosimetric characteristics for the I-Plant"T"M model 3600 "1"2"5I brachytherapy source  

International Nuclear Information System (INIS)

The dosimetric characteristics for a new brachytherapy seed source (I-Plant"T"M model 3600) were measured using LiF thermoluminescent dosimeters and appropriate phantom materials in conformance with the methodology and guidance provided by the AAPM Task Group 43. The I-Plant"T"M model 3600 is the successor to the I-Plant"T"M model 3500. The major difference between these sources is that the model 3600 contains a leaded-glass core to provide radio-opacity (while the model 3500 contains a silver core), which does not produce spectral contamination upon neutron activation. The dose rate constant #LAMBDA# for the model 3600 was determined to be 1.00 Gy h"-"1 U"-"1 (with a 6% overall relative standard deviation), compared to 1.01 cGy h"-"1 U"-"1 reported for the model 3500 in previous studies. The remaining dosimetric characteristics also are similar for both sources.

2005-06-01

319

Elephant's foot phenomenon in liquid storage tanks  

Energy Technology Data Exchange (ETDEWEB)

This paper presents a method for analyzing the seismic response of a flat bottomed cylindrical liquid storage tank to vertical earthquake excitation. Here, vertical earthquake acceleration is considered to correspond to an increase in the density of a stored liquid. Taking into account the vertical and horizontal earthquake loads, hydrostatic pressure, and considering restrictive moment and shear forces at shell-bottom welded joint, the author has calculated circumferential and longitudinal stresses. These are combined to more accurately approximate the stresses at the base shell course. The calculated result closely conforms to the actual damage, termed ''elephant's foot,'' observed in the fuel storage tanks damaged in the Tangshan earthquake. This result shows that the ''elephant's foot'' phenomenon is not caused by buckling of the tank shell due to longitudinal compressive ...

1983-01-01

320

Development status of a small, direct-injection diesel engine at Isuzu  

Energy Technology Data Exchange (ETDEWEB)

Development status of small direct injection diesel engine at Isuzu Motors Ltd. is reviewed. There is much difficulty in combustion optimization of small DI engines, due to small combustion chamber volume, large surface to volume ratio, wide engine speed range and so on. Novel ideas in the area of injection system, combustion chamber and induction swirl were tried to solve these problems and their effects are presented here. Our prototype DI engines which adopted some of these ideas has turned out to have better fuel economy by about 15 percent, 2 - 3 dB(A) higher noise level than IDI and almost the same power output performance as IDI. As to exhaust emissions, they have a possibility to conform to '86 California emission standards, in inertia weight classes up to 2625 LBS. The remaining problem areas are noise emission, durability of injection pump and cabin heater performance. These problems must be solved by further innovation, before DI engines will be ...

1985-01-01

321

Densification of ashes from a thermal power plant  

Energy Technology Data Exchange (ETDEWEB)

Power plants generate a great amount of ash during coal combustion. From this process two different kinds of ashes are extracted: fly ash (FA) and bottom ash (BA). In this work possible use of both fly and bottom ash as raw material for the ceramic industry is analyzed. The samples were formed by mechanical mixing of both kinds of ashes, and density evolution during conformation as structural ceramic (packing, pressing and sintering) was studied. It was verified that powders with larger fly ash content exhibited higher packing density resulting in compacts with improved green and sintered densities. Preheating treatments at temperatures above 600{sup o}C also increased the green and sintered densities. Dilatometric curves on compacts formed from FA and BA powders were run at constant heating rate and at isothermal cycles. From the analysis of these data it can be established that liquid-phase sintering is the densification mechanism present at 1180{sup o}C.

2003-07-01

322

Crystalline and Liquid Crystalline Organic-Inorganic Hybrid Salts with Cation-Sensitized Hexanuclear Molybdenum Cluster Complex Anion Luminescence  

British Library Electronic Table of Contents (United Kingdom)

Abstract The salts [Cnmim]2[Mo6Cl14] (mim = methylimidazolium; n = 4, 6, 12, 16, 18) have been obtained by reaction of CnmimCl with MoCl2. Thermal analysis shows the melting point decreases with increasing alkyl chain length of the cation. The imidazolium chloromolybdates(II) with n = 6-18 decompose above 340 C; [C18mim]2[Mo6Cl14] is thermally stable up to 390 C. All compounds are insensititve to the constituents of the atmosphere. Of the higher melting salts [Cnmim]2[Mo6Cl14] (n = 4, 6), high-quality single crystals could be obtained. Single-crystal X-ray structural analyses clearly show that the cluster complex anion [Mo6Cl14]2- has an electron-precise octahedral {Mo6} cluster. For [C4mim]2[Mo6Cl14], two polymorphs differing in the cation alkyl-side-chain conformation were obtained. The ...

2011-01-01

323

Correlation of Byrd and Selborne groups, with implications for the Byrd Glacier discontinuity, central Transantarctic Mountains, Antarctica  

International Nuclear Information System (INIS)

South of Byrd Glacier, central Transantarctic Mountains, Antarctica, Lower Cambrian Shackleton Limestone (Byrd Group) is divided into four informal members. The transition from Shackleton carbonates to clastics of Starshot Formation is conformable, with alternating units of limestone and argillite, and a thick succession of pillow basalt. Douglas Conglomerate is interbedded with and overlies Starshot Formation, and overlies folded Shackleton Limestone unconformably. Lower amphibolite-grade Selborne Group is composed of Madison Marble and Contortion Schist. The contact between the two formations is interbedded marble and schist, and includes metabasalt. We correlate Byrd Group with Selborne Group, Shackleton Limestone with Madison Marble, and Starshot Formation and Douglas Conglomerate with Contortion Schist. These correlations and the lack of equivalent lithologies to the north of Byrd Glacier imply that Byrd Glacier is the northern boundary of the Byrd ...

2004-06-01

324

Consequences of warm-up of a sector above 80K  

CERN Document Server

There may be circumstances when a sector has to be partially or totally warmed-up to temperatures above 80 K, that is when thermal dilatation starts to play a role. Some equipment have been identify as presenting a risk, like the non-conform "plug-in" modules in the arcs. Because of motion induced by thermal dilatation, the electrical (ElQA) quality control may also have to be done again after cool-down. The main reason identified so far for partial warm-up is the required maintenance of the cooling towers and the cryogenics plants. There is also the request from the vacuum group to periodically warm-up the beam screen to temperatures in the 100 K region to release and pump-out the gas crysorbed on the surface of the beam screen. Observed and expected temperature conditions and statistics on failures of PIMs in sectors which have been warmed-up will be presented in this contribution. Methods to detect buckled PIMs will be described, as well as a recommended ...

2009-01-01

325

Conceptual study on advanced PWR system  

Energy Technology Data Exchange (ETDEWEB)

In this study, the adoptable essential technologies and reference design concept of the advanced reactor were developed and related basic experiments were performed. (1) Once-through Helical Steam Generator: a performance analysis computer code for heli-coiled steam generator was developed for thermal sizing of steam generator and determination of thermal-hydraulic parameters. (2) Self-pressurizing pressurizer : a performance analysis computer code for cold pressurizer was developed. (3) Control rod drive mechanism for fine control : type and function were surveyed. (4) CHF in passive PWR condition : development of the prediction model bundle CHF by introducing the correction factor from the data base. (5) Passive cooling concepts for concrete containment systems: development of the PCCS heat transfer coefficient. (6) Steam injector concepts: analysis and experiment were conducted. (7) Fluidic diode concepts : analysis and experiment were conducted. (8) Wet thermal insulator : tests ...

1997-07-01

326

Comparison of newer synthetic and biological wound dressings.  

Science.gov (United States)

In 18 piglets, weighing 10-15 kg, third-degree burns or full-thickness skin excisions of 4 X 4 cm were inflicted. The effect of five dressing materials on adhesiveness to the wounds, appearance, conformability, wound contraction, bacterial count, and morphology of the wound was studied at the end of the seventh and fourteenth days without dressing changes. In 11 piglets with a burn wound, the most adherent dressing was collagen sponge(CS), followed by polyurethane sponge (PU), pigskin xenograph (PS), and xeroform. CS more effectively debrided the wound from coagulated necrotic tissue than the other dressings. Wound contraction was maximal with CS dressing (52%), followed by PU (44%), xeroform (32%), and PS (27%). In another seven piglets with full-thickness excised wounds, a velour dressing made of polytetrafluoroethylene (PTFE) or PU adhered significantly more than CS or PS. Wound contraction was greater with CS (37%) or PTFE (35%) than with PS (23%) or PU (18%). ...

1981-06-01

327

Circuit breaker lockout device  

Energy Technology Data Exchange (ETDEWEB)

An improved lockout assembly for locking a circuit breaker in a selected off or on position is provided. The lockout assembly includes a lock block and a lock pin. The lock block has a hollow interior which fits over the free end of a switch handle of the circuit breaker. The lock block includes at least one hole that is placed in registration with a hole in the free end of the switch handle. A lock tab on the lock block serves to align and register the respective holes on the lock block and switch handle. A lock pin is inserted through the registered holes and serves to connect the lock block to the switch handle. Once the lock block and the switch handle are connected, the position of the switch handle is prevented from being changed by the lock tab bumping up against a stationary housing portion of the circuit breaker. When the lock pin installed, an apertured-end portion of the lock pin is in registration with another hole on the lock block. Then a special scissors ...

1992-01-01

328

Biophysical analysis of DNA modified by 1,2-diaminocyclohexane platinum(II) complexes  

Energy Technology Data Exchange (ETDEWEB)

Modification of DNA and double-stranded deoxyoligonucleotides with antitumor 1,2-diamino-cyclohexanedinitroplatinum(II) (Pt-dach) complexes was investigated with the aid of physico-chemical methods and chemical probes of nucleic acid conformation. The three Pt-dach complexes were used which differed in isomeric forms of the dach non-leaving ligand-Pt(1R,2R-dach), Pt(1S,2S-dach) and Pt(1R,2S-dach) complexes. The latter complex has lower antitumor activity than the other two Pt-dach complexes. Pt(1R,2S-dach) complex exhibits the slowest kinetics of its binding to DNA and of the conversion of monofunctional binding to bifunctional lesions. The anomalously slow electrophoretic mobility of multimers of the platinated and ligated oligomers suggests that bifunctional binding of Pt-dach complexes to a d(GG) site within double-stranded oligonucleotides induces bending of the oligomer. It is proposed that different effects of the Pt-dach complexes on DNA observed in this ...

1992-01-25

329

Atomic force microscopy and surface-enhanced Raman scattering detection of DNA based on DNA-nanoparticle complexes  

Energy Technology Data Exchange (ETDEWEB)

We report a simple method for the label-free detection of double-stranded DNA using surface-enhanced Raman scattering (SERS). We prepared cetyltrimethylammonium bromide (CTAB)-capped silver nanoparticles and a DNA-nanoparticle complex by adding silver nanoparticles to {lambda}-DNA solutions. In the present study, the utilization of CTAB-capped silver nanoparticles facilitates the electrostatic interaction between DNA molecules and silver nanoparticles; at the same time, the introduction of DNA avoids adding aggregating agent for the formation of nanoparticle aggregates to obtain large enhancement of DNA, because the DNA acts as both the probe molecules and aggregating agent of Ag nanoparticles. Atomic force microscopy (AFM) studies show that the morphology of DNA-Ag nanoparticle complexes seems to be determined by the concentrations of the DNA and the nanoparticles. Surface-enhanced Raman scattering (SERS) studies show that the morphology of the complexes plays a significant role in ...

2009-03-25

330

A single amino acid substitution results in a retinoblastoma protein defective in phosphorylation and oncoprotein binding  

International Nuclear Information System (INIS)

The authors have previously identified a small-cell lung cancer cell line (NCI-H209) that expresses an aberrant, underphosphorylated form of the retinoblastoma protein RB1. Molecular analysis of RB1 mRNA from this cell line revealed a single point mutation within exon 21 that resulted in a nonconservative amino acid substitution (cysteine to phenylalanine) at codon 706. Stable expression of this mutant RB1 cDNA in a human cell line lacking endogenous RB1 demonstrated that this amino acid change was sufficient to inhibit phosphorylation. In addition, this cysteine-to-phenylalanine substitution also resulted in loss of RB1 binding to the simian virus 40 large tumor and adenovirus E1A transforming proteins. These results confirm the importance of exon 21 coding sequences and suggest that the cysteine residue at codon 706 may play a role in achieving a specific protein conformation essential for protein-protein interactions.

331

222-S Laboratory maintenance implementation plan  

Energy Technology Data Exchange (ETDEWEB)

This Maintenance Improvement Plan has been developed for maintenance functions associated with the 222-S Laboratory. This plan is developed from the guidelines presented by Department of Energy (DOE) Order 4330.4B, Maintenance Management Program (DOE 1994), Chapter 11. The objective of this plan is to provide information for establishing and identifying WMH conformance programs and policies applicable to implementation of DOE Order 4330.4B guidelines. In addition, this maintenance plan identifies the actions necessary to develop a cost effective and efficient maintenance program at 222-S Laboratory. Maintenance activities are mainly going to be performed by existing maintenance organizations within Waste Management Federal Services of Hanford (WMH). Most maintenance performed at 222-S Laboratory is performed by the 222-S Laboratory maintenance organization. This 222-S Laboratory Maintenance Implementation Plan provides the interface requirements and ...

1997-08-13

332

Solution conformations of CaCl sub 2 and Ca(NO sub 3 ) sub 2 complexes of chiral tetramethyl 18-crown-6 macrocycles: A 1D and 2D sup 1 H and sup 13 C NMR investigation  

Energy Technology Data Exchange (ETDEWEB)

One- and two-dimensional NMR techniques have been used to investigate the solution structures of (2S,6S,11S,15S)-2,6,11,15-tetramethyl-1,4,7,10,13,16-hexaoxacyclooctadecane (I) and (2R,3R,11R,12R)-2,3,11,12-tetramethyl-1,4,7,10,13,16-hexaoxyacyclooctadecane (II) macrocycle complexes of CaCl{sub 2} and Ca(NO{sub 3}){sub 2} in CDCl{sub 3}. Previous chiroptical studies of these and similar crown complexes by circularly polarized luminescence (CPL), total luminescence (TL), and circular dichroism (CD) spectroscopy have shown that the macrocycle asymmetric carbons in these complexes constrain the ring such that the sense of the ring twist in the S chiral ring complexes is opposite to that in the R chiral ring complexes. These studies have also shown that there is an added chirality element in the di- and trivalent (alkaline earth and lanthanide metal, respectively) nitrate complexes of I and II associated with the twist of the nitrate anions relative to one another as they sterically ...

1989-10-04

333

Well log interpretation of certain geothermal fields in the Imperial Valley, California  

Energy Technology Data Exchange (ETDEWEB)

This study reviews the wireline log responses of some geothermal fields in the Imperial Valley, California. The fields under study include the Heber, the East Mesa, the Brawley, and the Westmoreland. The well logs used in the study did not include all the wireline surveys obtained by the operators. The selected well logs obtained under special arrangements with the operators were chosen to maintain the anonymity of specific well locations but are only representative of each area. Analysis of the well logs indicates that on an individual field basis, the well logs are excellent for correlation purposes. The presence of extremely saline fluids in some fields precludes the monitoring of Q/sub v/ (cation exchange capacity per unit volume) profile for detection of hydrothermally altered zones. The producing sections in all the fields are characterized by low porosity and high ...

1984-03-01

334

Wave electromagnetic fields induced by instantaneous braking of charges  

International Nuclear Information System (INIS)

Exact expressions for wave electromagnetic fields during instantaneous braking of two differently charged discs uniformly moving in the opposite directions have been derived. Analysis of their properties has been made. It is shown that electromagnetic wave fields during instantaneous braking of charges have a tearing nature and the Umov-Poynting theorem in the integral form is realized only at a certain value of parameter #alpha# which determines charges rates at the moment of braking. The value of parameter #alpha# is in the ranges from 0.5 to #sq root#3/2. The wave field is formed already in the absence of motion of charged discs. It is a good example confirming the conclusion that in the case of nonstationary electromagnetic fields, performance of reaction force of the wave field can differ fram radiation energy.

335

Strong laser fields as a probe for fundamental physics  

CERN Document Server

Upcoming high-intensity laser systems will be able to probe the quantum-induced nonlinear regime of electrodynamics. So far unobserved QED phenomena such as the discovery of a nonlinear response of the quantum vacuum to macroscopic electromagnetic fields can become accessible. In addition, such laser systems provide for a flexible tool for investigating fundamental physics. Primary goals consist in verifying so far unobserved QED phenomena. Moreover, strong-field experiments can search for new light but weakly interacting degrees of freedom and are thus complementary to accelerator-driven experiments. I review recent developments in this field, focusing on photon experiments in strong electromagnetic fields. The interaction of particle-physics candidates with photons and external fields can be parameterized by low-energy effective actions and typically predict characteristic optical ...

2008-01-01

336

On the electrodynamics of tachyons  

International Nuclear Information System (INIS)

Electrodynamic properties of processes involving charged tachyons are considered in connection with the real superluminal Lorentz transformations. These transformations are interpreted without making use of a tachon corridor and so that the interaction of tachyons from subluminal sources with ordinary matter is Lorentz invariant. Transformations of the electromagnetic fields are deduced from the extended principle of relativity. They are necessary in order to obtain the field equations that are satisfied by fields obeying Maxwell equations relative to superluminal inertial frames with respect to subluminal inertial frames. The field equations allow one to get the dependence of the field energy density and its current on the field strengths. The resulting equations are applied in a discussion of plane electromegnetic waves, sent out by a superluminal source. The ...

337

Native Synthetic Imaging of Smoothed Particle Hydrodynamics density fields using gridless Monte Carlo Radiative Transfer  

CERN Document Server

An algorithm for creating synthetic telescope images of Smoothed Particle Hydrodynamics (SPH) density fields is presented, which utilises the adaptive nature of the SPH formalism in full. The imaging process uses Monte Carlo Radiative Transfer (MCRT) methods to model the scattering and absorption of photon packets in the density field, which then exit the system and are captured on a pixelated image plane, creating a 2D image (or a 3D datacube, if the photons are also binned by their wavelength). The algorithm is implemented on the density field directly: no gridding of the field is required, allowing the density field to be described to an identical level of accuracy as the simulations that generated it. Some applications of the method to star and planet formation simulations are presented to illustrate the advantages of this new technique, and suggestions as to how this framework ...

2010-01-01

338

Mississippi exploration field trials using microbial, radiometrics, free soil gas, and other techniques  

Energy Technology Data Exchange (ETDEWEB)

The Mississippi Office of Geology has conducted field trials using the surface exploration techniques of geomicrobial, radiometrics, and free soil gas. The objective of these trials is to determine if Mississippi oil and gas fields have surface hydrocarbon expression resulting from vertical microseepage migration. Six fields have been surveyed ranging in depth from 3,330 ft to 18,500 ft. The fields differ in trapping styles and hydrocarbon type. The results so far indicate that these fields do have a surface expression and that geomicrobial analysis as well as radiometrics and free soil gas can detect hydrocarbon microseepage from pressurized reservoirs. All three exploration techniques located the reservoirs independent of depth, hydrocarbon type, or trapping style.

1995-12-31

339

Field theory description of neutrino oscillations  

CERN Document Server

We review various field theory approaches to the description of neutrino oscillations in vacuum and external fields. First we discuss a relativistic quantum mechanics based approach which involves the temporal evolution of massive neutrinos. To describe the dynamics of the neutrinos system we use exact solutions of wave equations in presence of an external field. It allows one to exactly take into account both the characteristics of neutrinos and the properties of an external field. In particular, we examine flavor oscillations an vacuum and in background matter as well as spin flavor oscillations in matter under the influence of an external electromagnetic field. Moreover we consider the situation of hypothetical nonstandard neutrino interactions with background fermions. In the case of ultrarelativistic particles we reproduce an effective Hamiltonian which is used in the standard ...

2010-01-01

340

Field Generation and Dissipation Currents in Thunderclouds as a Result of the Movement of Charged Hydrometeors.  

Science.gov (United States)

The calculations of Gay et al. of the terminal velocities of charged hydrormeteors in the presence of electric fields have formed the basis of computations of the charging current density J flowing through a thunder-cloud as a result of the operation of a precipitative mechanism of cloud electrification. Values of J were calculated for a range of values of field strength E, precipitation rate pO, precipitation content L, cloud water content C, charge distribution, total separated charge, and the fraction of the small particles that have undergone a charging event.It is found that the estimated field required for the initiation of a lightning stroke (3.5 kV cm1 can be achieved only over a narrow range of conditions. The ease with which precipitative mechanisms can produce breakdown fields is considerably increased, however, if account is taken of spatial inhomogenities in the field.

1975-05-01

341

Electronic and spectral properties of adatoms on metals in electrostatic fields  

Energy Technology Data Exchange (ETDEWEB)

Electrostatic fields of the order of 1 V/Angst, as they occur at field emission tips, are comparable to those experienced by valence electrons in atoms and molecules. Such fields are strong enough to induce a significant redistribution of the valence charge in chemical bonds. In this work we investigate the effects on the electronic properties of a single adatom on a metal surface induced by the presence of an electrostatic field. In particular we present the results of a full ab initio DFT calculation, within the embedding method, of the CCV Auger spectra of Si and Mg atoms in and on a jellium-Ag host. Differently from impurities in bulk, Auger spectral profiles of adsorbates on metal surfaces can show notable modifications due to the applied electric field.

2002-11-15

342

Conservation laws. Generation of physical fields. Principles of field theories  

CERN Document Server

In the paper the role of conservation laws in evolutionary processes, which proceed in material systems (in material media) and lead to generation of physical fields, is shown using skew-symmetric differential forms. In present paper the skew-symmetric differential forms on deforming (nondifferentiable) manifolds were used in addition to exterior forms, which have differentiable manifolds as a basis. Such skew-symmetric forms (which were named evolutionary ones since they possess evolutionary properties), as well as the closed exterior forms, describe the conservation laws. But in contrast to exterior forms, which describe conservation laws for physical fields, the evolutionary forms correspond to conservation laws for material systems. The evolutionary forms possess an unique peculiarity, namely, the closed exterior forms are obtained from these forms. It is just this that enables one to describe the process of generation of physical ...

2007-01-01

343

Complexity of chaotic fields and standard model parameters  

CERN Document Server

In order to understand the parameters of the standard model of electroweak and strong interactions (coupling constants, masses, mixing angles) one needs to embed the standard model into some larger theory that accounts for the observed values. This means some additional sector is needed that fixes and stabilizes the values of the fundamental constants of nature. In these lecture notes we describe in nontechnical terms how such a sector can be constructed. Our additional sector is based on rapidly fluctuating scalar fields that, although completely deterministic, evolve in the strongest possible chaotic way and exhibit complex behaviour. These chaotic fields generate potentials for moduli fields, which ultimately fix the fundamental parameters. The chaotic dynamics can be physically interpreted in terms of vacuum fluctuations. These vacuum fluctuations are different from those of QED or QCD but coupled with the same moduli ...

2007-01-01

344

An overview of field-specific designs of microbial EOR  

Energy Technology Data Exchange (ETDEWEB)

The selection and design of an MEOR process for application in a specific field involves geological, reservoir, and biological characterization. Microbially mediated oil recovery mechanisms (bigenic gas, biopolymers, and biosurfactants) are defined by the types of microorganisms used. The engineering and biological character of a given reservoir must be understood to correctly select a microbial system to enhance oil recovery. This paper discusses the methods used to evaluate three fields with distinct characteristics and production problems for the applicability of MEOR would not be applicable in two of the three fields considered. The development of a microbial oil recovery process for the third field appeared promising. Development of a bacterial consortium capable of producing the desired metabolites was initiated, and field isolates were characterized.

1995-12-31

345

Use of hydrolyzed polyacrylonitrile for limiting the influxes of water at the Sokolovgoroskiy field  

Energy Technology Data Exchange (ETDEWEB)

A formula and technology are presented for the preparation of a hydrolyzed polyacrylonitrile (gipane) from the wastes of chemical production, analysis of the results of working to use them to insulate influxes of water in the extracting wells of the Sokolovogorskiy field.

1980-01-01

346

Ultra high field magnetic resonance imaging  

International Nuclear Information System (INIS)

Understanding human brain function, brain development and brain dysfunction is one of the great challenges of the twenty first century. Biomedical imaging has now run up against a number of technical constraints that are exposing limits to its potential. In order to overcome the current limits to high-field magnetic resonance cerebral imaging (MRI) and unleash its fullest potential, the Cea has built NeuroSpin, an ultra-high-field neuroimaging facility at its Saclay centre (in the Essonne). NeuroSpin already boasts three fully operational MRI systems. The first is a 3-tesla high-field system and the second is a very-high-field 7-tesla system, both of which are dedicated to clinical studies and investigations in humans, while the third is an ultra-high-field 17.65-tesla system designed for studies on small animals. In 2011, NeuroSpin will be commissioning an 11.7-tesla ...

347

The effect of the primary collimator and flattening filter on asymmetric fields for a Siemens PRIMUS linear accelerator  

CERN Document Server

Homogeneity for highly asymmetric fields has been studied for a Siemens PRIMUS linear accelerator. The flattening filter has a radius smaller than the primary collimator one, creating inhomogeneities that affect large fields in areas far from the collimator axis, and asymmetric fields with large offset. Profiles and absolute dose have been measured in fields with two jaws at maximal position (20 cm) and the other two at maximal overtravel (10 cm.), corresponding to 10 x 10 fields with extreme offset. Profiles have a remarkable gradient decreasing towards the beam edge, making these fields unsuitable for treatments. Results show that the design of the primary collimator and flattening filter assembly has direct consequences in homogeneity. This can have clinical consequences for treatments involving fields that include these inhomogeneous ...

2005-01-01

348

The DP-2 addresses the need for vertical operating aircraft with ...  

Science.gov (United States)

C-130J payload reduced to make radius. ** Current C-17A uses 3000 ft field, C- 17A+ estimated cost of $378M per plane with. 2000 ft field length, ...

349

Test API: Class SearchCriteria  

Science.gov (United States)

Overview  Package   Class  Use  Tree  Deprecated  Index  Help   PREV CLASS   NEXT CLASS FRAMES    NO FRAMES SUMMARY:  INNER | FIELD | CONSTR | METHOD DETAIL:  FIELD | CONSTR | METHOD gov.nih.nci.dc.database Class SearchCriteria java.lang.Object |

350

Safety Implications of High-Field MRI: Actuation of Endogenous Magnetic Iron Oxides in the Human Body  

UK PubMed Central (United Kingdom)

BackgroundMagnetic Resonance Imaging scanners have become ubiquitous in hospitals and high-field systems (greater than 3 Tesla) are becoming increasingly common. In light of recent...Full Text Available

351

Risk of hematological malignancies associated with magnetic fields exposure from power lines: a case-control study in two municipalities of northern Italy  

UK PubMed Central (United Kingdom)

BackgroundSome epidemiologic studies have suggested an association between electromagnetic field exposure induced by high voltage power lines and childhood leukemia, but null results...Full Text Available

352

Residential magnetic fields and childhood leukemia: a meta-analysis.  

UK PubMed Central (United Kingdom)

OBJECTIVES: This article uses meta-analysis methodology to examine the statistical consistency and importance of random variation among results of epidemiologic studies of residential magnetic field...Full Text Available

1998-12-01

353

Reproductive Success of Cavity-nesting Birds Breeding under High-voltage Powerlines  

Science.gov (United States)

... biological effects of electromagnetic fields (EMFs) produced by high-voltage transmission lines have come under intense scrutiny, mostly with respect ... biological effects of electromagnetic fields (EMFs...

354

Relativistic mean field theory and applications in finite nuclei  

Energy Technology Data Exchange (ETDEWEB)

Relativistic mean field (RMF) theory is applied to modern problems of nuclear structure, such as the description of rotating bands in super-deformed nuclei or the investigation of neutron halos in light exotic nuclei. (orig.)

1997-05-01

355

Quaternionic formulation for electromagnetic-field equations  

Energy Technology Data Exchange (ETDEWEB)

The quaternionic formalism for subluminal field equations (Maxwell's equations) and its interrelationship with complex superluminal Lorentz transformations have been given and it has been shown that the quaternionic forms of relativistic equations describe tachyons.

1983-07-02

356

QSAR Studies of Copper Azamacrocycles and Thiosemicarbazones  

UK PubMed Central (United Kingdom)

Genetic algorithms (GA) were used to develop specific copper metal-ligand force field parameters for the MM3 force field, from a combination of crystallographic structures and ab initio...Full Text Available

2005-08-25

357

Population exposure to power-frequency fields: concepts, components, and control  

Energy Technology Data Exchange (ETDEWEB)

There are many sources of population exposures to power-frequency (50/60 Hz) electric and magnetic fields including household appliances and wiring, neighborhood distribution circuits, and high-voltage transmission lines. Bioeffects studies were unable to demonstrate that exposures to power-frequency fields can affect public health. Researcher have likewise been unable to show that the health effects of such exposures are negligible. State and federal regulatory agencies are, therefore, grappling with questions of whether and how to regulate the sitting or design of new extra high-voltage transmission lines so as to control the ground-level fields to which people are exposed. The purpose of this dissertation is to illuminate some of the exposure-related aspects of these question. A taxonomy of the relationship between field encounter and effect is developed to clarify the meaning of terms such as ...

1986-01-01

358

Perturbations of the Plebanski metric in general relativity. II. Perturbations of the fermion field.  

Science.gov (United States)

We obtain the radial Dirac equations for the Plebanski metric and transform these equations into one-dimensional wave equations. Finally we conclude with the result that the electron and the neutrino fields are not superradiant.

1986-09-01

359

Optimization of water injection into vapor-dominated geothermal reservoirs  

Energy Technology Data Exchange (ETDEWEB)

Water injection into a vapor-dominated geothermal reservoir is an effective method of sustaining steam production from the field. Injection puts additional water to the reservoir and raises the prevailing reservoir pressure. This process improves the field`s productivity. However, the increased pressure also increases the water retention capacity of the reservoir rocks through the effects of adsorption and capillary condensation. Due to the significant costs associated with water injection programs, optimizing injection not only involves maximizing the energy yield from the resource but also the present worth of the project. Two crucial parameters that need to be established are: (1) how much to inject; and, (2) when to inject it. This study investigated the optimal design of these parameters. It was found that comparable energy yield can be attained for injection programs that are initiated at various stages of the field`s ...

1996-12-31

360

Nutrient supply, growth and development of field vegetables  

Environmental Research Database

DescriptionThe UK horticulture and agriculture industries rely on large inputs of mineral nitrogen (N), phosphorus (P) and potassium (K) fertilisers to maintain product yield and quality. Recovery of applied fertilisers by field crops is inefficient (routinely

2007-01-31

361

Numerical field calculations considering the human subject for engineering and safety assurance in MRI  

UK PubMed Central (United Kingdom)

Numerical calculations of static, switched, and radiofrequency (RF) electromagnetic (EM) fields considering the geometry and EM properties of the human body are used increasingly in MRI to explain...Full Text Available

2009-11-01

362

Neurobehavioral effects of power-frequency electromagnetic fields.  

UK PubMed Central (United Kingdom)

Some laboratory experiments have suggested that power-frequency electric and magnetic fields (EMF) may be capable of influencing calcium efflux from cell membranes, pineal function, and circadian rhythms....Full Text Available

1993-12-01

363

Method of describing dose distributions in computer design of teleradiotherapy  

International Nuclear Information System (INIS)

Method for description of X-ray radiation dose distribution based on semiempirical description of dose fields is suggested. At that dose field description parameters can be easily individualized for concrete X-ray device.

364

Magnetic Levitation of MC3T3 Osteoblast Cells as a Ground-Based Simulation of Microgravity  

UK PubMed Central (United Kingdom)

Diamagnetic samples placed in a strong magnetic field and a magnetic field gradient experience a magnetic force. Stable magnetic levitation occurs when the magnetic force exactly counter balances...Full Text Available

2009-11-01

365

Low-frequency fields - sources and exposure; Niederfrequente Felder - Quellen und Exposition  

Energy Technology Data Exchange (ETDEWEB)

The author briefly discusses definition of terms, gives an introduction to measurement techniques and describes the characteristics of various low-frequency fields and their causes using typical examples: natural electric fields (thunderstroms), natural magnetic fields, technical electric constant fields (urban transportation, households), static magnetic fields (urban transportation, nuclear magnetic resonance imaging), technical electric alternating fields (high-voltage transmission lines, households), and magnetic alternating fields (high-voltage transmission lines). The author discusses both occupational exposure and that of the general public while underpinning his statements by numerous tables, measurement diagrams and charts. (Uhe) [Deutsch] Nach einer kurzen Diskussion der Begriffsdefinitionen und einer Einfuehrung in die Messtechnik ...

1993-06-01

366

Insecticide resistance resulting from sequential selection of houseflies in the field by organophosphorus compounds*  

UK PubMed Central (United Kingdom)

Although cross-resistance in houseflies to the organophosphates has eliminated numerous potentially useful compounds from field use, the ”subgroup” specificity of this phenomenon has...Full Text Available

1971-01-01

367

Hydrodynamics in an external field  

CERN Document Server

The methods of statistical dynamics are applied to a fluid with 5 conserved fields (the mass, the energy, and the three components of momentum) moving in a given external potential. When the potential is zero, we recover a previously derived system of parabolic differential equations, called "corrections to fluid dynamics".

2002-01-01

368

Glutamate Receptor-Mediated Restoration of Experience-Dependent Place Field Expansion Plasticity in Aged Rats  

UK PubMed Central (United Kingdom)

Place fields of hippocampal pyramidal cells expand asymmetrically when adult rats repeatedly follow the same route. This behaviorally-induced expression of neuronal plasticity utilizes an NMDAR-dependent,...Full Text Available

2008-06-01

369

Field Investigations in the Tow Study Programme for Coastal Sediment Transport in the Netherlands.  

Science.gov (United States)

Field campaigns were conducted in 1981 and 1982/83 on the Dutch coast near Egmond. Measurements were made of surface elevations, water velocities and sediment concentrations in 3 to 8 surf zone locations and 2 to 5 offshore locations simultaneously. A des...

1985-01-01

370

Exactly solvable field-theoretical model with tachyons  

Energy Technology Data Exchange (ETDEWEB)

Explicit soliton solutions describing the inelastic interaction between sub- and superluminal particles are found within the framework of a new integrable model of relativistic classical field theory. The corresponding energies are nonnegative irrespective of the choice of reference frame.

1988-09-01

371

Evaluation of field application of boric acid  

International Nuclear Information System (INIS)

Results of field applications of boric acid in the secondary coolant circuits of seven PWR units for the purpose of reducing the rate of corrosion denting are reported. Based on available data at the power plants considered in this study, it was not possible to support or refute the benefit of using boric acid secondary water treatment.

1985-03-01

372

Epidemiological appraisal of studies of residential exposure to power frequency magnetic fields and adult cancers.  

UK PubMed Central (United Kingdom)

OBJECTIVES: To appraise epidemiological evidence of the purported association between residential exposure to power frequency magnetic fields and adult cancers. METHODS: Literature review and epidemiological...Full Text Available

1996-08-01

373

Epidemiologic studies of electric and magnetic fields and cancer: strategies for extending knowledge.  

UK PubMed Central (United Kingdom)

Epidemiologic research concerning electric and magnetic fields in relation to cancer has focused on the potential etiologic roles of residential exposure on childhood cancer and occupational exposure...Full Text Available

1993-12-01

374

Electromagnetic fields, pacemakers and defibrillators; Champs electromagnetiques, cardiostimulateurs et defibrillateurs  

Energy Technology Data Exchange (ETDEWEB)

Presentation of electromagnetic sources constituted by various radio transmitters contributing to different radio communication services in the environment. Results of a measures campaign to assess the electromagnetic field in the close neighbourhood of various stations. Analysis by frequency domains. (author)

2004-07-01

375

Electric field measurement on time domain generated by corona on insulators on distribution systems  

Energy Technology Data Exchange (ETDEWEB)

Radio interference and TV interference are being a problem in urban and rural areas. This interference is generated by high voltage transmission lines as well as distribution lines. The radio noise can be produced by polluted or damaged insulators, and by metal parts of the distribution lines. The corona effect on the surface of the dielectric material produces high frequency electromagnetic fields during the ionization and during the recombination period. Fields of different intensity are produced by positive voltage and negative voltage. The insulator flashover (leaking current) also produces electromagnetic fields. A new technique to measure these fields was developed. This technique measures the radiated fields on time domain and on frequency domain. This permits us to characterize the radiated field and thus identify the type of the source. Several ...

1996-12-31

376

Electric and magnetic field exposures for people living near a 735-kilovolt power line.  

UK PubMed Central (United Kingdom)

The purpose of this study was to assess the effect of a 735-kV transmission line on the electric and magnetic field exposures of people living at the edge of the line's right of way. Exposure of 18...Full Text Available

1995-09-01

377

Coulomb scattering for scalar field in Schroedinger picture  

Energy Technology Data Exchange (ETDEWEB)

The scattering of a charged scalar field on Coulomb potential on de Sitter space-time is studied using the solution of the free Klein-Gordon equation. We find that the scattering amplitude is independent of the choice of the picture and in addition the total energy is conserved in the scattering process.

2008-07-31

378

Continuum Polarizable Force Field within the Poisson-Boltzmann Framework  

UK PubMed Central (United Kingdom)

We have developed and tested a complete set of nonbonded parameters for a continuum polarizable force field. Our analysis shows that the new continuum polarizable model is consistent with B3LYP/cc-pVTZ...Full Text Available

2008-06-26

379

Assessment of structural changes of human teeth by low-field nuclear magnetic resonance (NMR)  

UK PubMed Central (United Kingdom)

A technique of low-field pulsed proton nuclear magnetic resonance (NMR) spin relaxation is described for assessment of age-related structural changes (dentin and pulp) of human teeth in...Full Text Available

2010-01-01

380

Adaptations of the Saker-Solomons test: simple, reliable colorimetric field assays for chloroquine and its metabolites in urine.  

UK PubMed Central (United Kingdom)

Two field-adapted colorimetric methods for measuring the antimalarial drug chloroquine in urine are described. Both are modifications of the method of Saker and Solomons for screening urine for phencyclidine...Full Text Available

1989-01-01

381

A case cohort study of suicide in relation to exposure to electric and magnetic fields among electrical utility workers.  

UK PubMed Central (United Kingdom)

OBJECTIVES--This case cohort study examines whether there is an association between exposure to electric and magnetic fields and suicide in a population of 21,744 male electrical utility workers from...Full Text Available

1996-01-01

383

The Airborne Field Artillery: From Inception to Combat ...  

Science.gov (United States)

... With these facts of history as background and given the 82nd Airborne Division's previous combat experiences in Sicily and Salerno, what ...

2004-06-17

384

Tachyons and quantum field theory  

International Nuclear Information System (INIS)

The problems associated with treating tachoyons in quantum field theory are discussed, and the quantization proposed by Arons and Sudarshan is chosen as the most satisfactory of the presently available methods, although it is unable to describe interactions in its present form. In order to help determine whether suitable S-matrices can ever be found, a perturbation-type expansion for the S-matrix is considered. It is shown that if the first order term is any polynomial in the tachyon field and its conjugate, then the reinterpreted, or physical, S-matrix will violate unitarity. An example shows that the inclusion of derivatives of the field is also expected to produce non-unitary physical S-matrices. The indications are that a correct interesting theory of tachyons must be non-local.

385

Sub-wavelength localization of near-fields in coupled metallic spheres for single emitter polarization analysis  

CERN Document Server

We numerically demonstrate selective near-field localization determined by the polarization state of a single emitter coupled to plasmonic nano-cluster. Seven gold nanospheres are carefully arranged such that up to ten polarization states of the single emitter, including linear, circular, and elliptical polarizations, can be distinguished via the distinct field localization in four gaps. The ability to transform polarization state into field spatial localization may find application for single emitter polarization analysis.

2011-01-01

386

Sharp asymptotics for metastability in the random field Curie-Weiss model  

CERN Document Server

In this paper we study the metastable behavior of one of the simplest disordered spin system, the random field Curie-Weiss model. We will show how the potential theoretic approach can be used to prove sharp estimates on capacities and metastable exit times also in the case when the distribution of the random field is continuous. Previous work was restricted to the case when the random field takes only finitely many values, which allowed the reduction to a finite dimensional problem using lumping techniques. Here we produce the first genuine sharp estimates in a context where entropy is important.

2008-01-01

387

Scalar field cosmology in three-dimensions  

Energy Technology Data Exchange (ETDEWEB)

We study an analytical solution to the Einstein's equations in 2 + 1-dimensions. The space-time is dynamical and has a line symmetry. The matter content is a minimally coupled, massless, scalar field. Depending on the value of certain parameters, this solution represents three distinct space-times. The first one is at space-time. Then, we have a big bang model with a negative curvature scalar and a real scalar field. The last case is a big bang model with event horizons where the curvature scalar vanishes and the scalar field changes from real to purely imaginary. (author)

2001-09-01

388

Remote handling and robotics in nuclear field  

International Nuclear Information System (INIS)

The application of remote handling and robotics, the state of the art and some uses in the man-machine interface are described. (E.G.).

389

RESULTS ON INCOLOY 800 AND ALLIED STEAM ...  

Science.gov (United States)

... Title : RESULTS ON INCOLOY 800 AND ALLIED STEAM GENERATOR MATERIALS IN FLORIDA FIELD CORROSION TESTS,. ...

390

RESEARCH REPORT 248 ON THE EQUILIBRIUM OF ELECTRON - NASA ...  

Science.gov (United States)

then, the toroidal containment of charged plasmas by electric fields is comparable to the toroidal containment of neutral plasmas using the ...

391

Positronium formation in liquid nitrogen as a function of electric field  

International Nuclear Information System (INIS)

The intensity of the orthopositronium component and its lifetime have been measured in liquid nitrogen as a function of electric field. While the lifetime remains constant at about 12.5 ns, the fraction of positronium formed is about 20% at zero field and decreases monotonically to an asymptotic value near 6% as the field is raised to 3.2 MV m"-"1. The decrease is roughly exponential with a drop off rate of 2.0 MV m"-"1. The results are a further indication of the importance of Mogensen's spur mechanism in the positronium formation process. (author).

1993-07-01

392

Polyurethane - positioning aids in radiotherapy  

Energy Technology Data Exchange (ETDEWEB)

A simple and cheap method is described for the manufacturing of individual positioning aids made of foamed polyurethane. Some examples are given to demonstrate the applicability of these positioning aids for the irradiation of different body regions. The reproducibility of the radiation field in the head and neck area was investigated with and without positioning aid. It was proved that the field is adjusted more exactly when positioning aids are applied. The dosimetric investigations performed showed a negligible influence of foamed polyurethane on the radiation quality. So the positioning aids could be left within the radiation field when drawing the field borders.

1985-06-01

393

Plasma treatment of polymer dielectric films to improve capacitive energy storage  

Science.gov (United States)

Demand for compact instrumentation, portable field equipment, and new electromagnetic weapons is

1994-01-01

394

Numerical prediction of flow field and particle trajectory in a hard disk drive  

Energy Technology Data Exchange (ETDEWEB)

A flow field and particle trajectory in a HDD (Hard Disk Drive) between two rotating disks in axisymmetric enclosures is investigated using CFD code FLUENT/UNS. The RNG k-{epsilon} model is used as a turbulent model. In this study, the flow field between two disks are symmetric, and the flow field near the enclosure is very complex. Cross stream vectors are shown both for blowing and no blowing from the hub. The larger a particle, the more fast the particle deposits at the walls. In the case of blowing from the hub, the more fast the particle deposits at the walls. (author). 9 refs., 12 figs., 1 tab.

1999-11-01

395

Nuclear moments of the 11/2"- isomer in "1"8"7Ir  

International Nuclear Information System (INIS)

... excited states iridium 187 isomeric nuclei magnetic fields nuclear electric

396

NASA TECH BRIEF  

Science.gov (United States)

Magnetic Forming Studies. The use of transient high magnetic-field devices has made possible the generation of very large accurately ...

397

Moderate Deviations for a Curie-Weiss model with dynamical external field  

CERN Document Server

In the present paper we prove moderate deviations for a Curie-Weiss model with external magnetic field generated by a dynamical system, as introduced by Dombry and Guillotin-Plantard. The results extend those already obtained in the case of a constant external field by Eichelsbacher and L\\"owe. The Curie-Weiss model with dynamic external field is related to the so called dynamic Z-random walks. We also prove a moderate deviation result for the dynamic Z-random walk, completing the list of limit theorems for this object.

2011-01-01

399

Interference phenomena at the elastic collision of atoms with formation of the Feshbach resonance in the presence of laser radiation field  

British Library Electronic Table of Contents (United Kingdom)

Resonant scattering of atoms with formation of the Feshbach resonance in the presence of a laser radiation coupling the levels of two bound atoms (a molecule) is considered. The laser field leads to a second resonance in scattering and broadening of resonances, which facilitates the possibility of experimental observation of asymmetry of the total scattering cross-section arising because of interference between resonant and potential scatterings. The effects associated with interference of the two channels of decay of a bound system of two atoms (a molecule) in the laser field are studied. An expression is obtained for the scattering length in collision of two cold atoms in the field of laser radiation.

2011-01-01

401

Injection and extraction magnets: septa  

CERN Document Server

An accelerator has limited dynamic range: a chain of accelerators is required to reach high energy. A combination of septa and kicker magnets is frequently used to inject and extract beam from each stage. The kicker magnets typically produce rectangular field pulses with fast rise- and/or fall-times, however the field strength is relatively low. To compensate for their relatively low field strength, the kicker magnets are generally combined with electromagnetic septa. The septa provide relatively strong field strength but are either DC or slow pulsed. This paper discusses injection and extraction systems with particular emphasis on the hardware required for the septa.

2010-01-01

402

Hybridisation and crystal field in YbPd sub 2 Si sub 2  

Energy Technology Data Exchange (ETDEWEB)

Experimental data in the hybridised compound YbPd{sub 2}Si{sub 2} is compared with the results obtained with a recently proposed hybridisation model, based on the ''large-degeneracy expansion'' approximation, which takes into account the crystal field splittings of the rare earth ion energy levels. With a unique set of parameters, satisfactory agreement is simultaneously obtained for the thermal variation of the electronic specific heat, of the magnetic susceptibility and of the electric field gradient at the Yb site, as well as for the field variation of the low temperature magnetisation. (orig.).

1991-02-01

404
405

Environmental and health effects of electric and magnetic fields from transmission lines  

International Nuclear Information System (INIS)

The paper outlines the underlying physical mechanisms by which electric and magnetic fields exist, with particular reference to high voltage transmission lines. Epidemiological and laboratory studies are the two approaches used in research into the subject and the shortcomings and inconstancies in the results are mentioned. Recent epidemiological results are presented together with possible mechanisms between fields and the human body. Attention is drawn to the work of certain international and national bodies concerning the alleged association between electromagnetic fields and ill-health, and their conclusions are reported. Finally, the policy of the Electricity Supply Board in Ireland is outlined. 2 figs.

1995-05-01

407

Development of power supplies for compact medical synchrotron  

International Nuclear Information System (INIS)

A compact medical synchrotron is being developed which aims to promote the advanced radiotherapy based on the accelerator. As it is small-sized, a high field dipole magnet of 3 T at 200 kA is used. It is excited by the discharge current of the capacitor bank of which waveform is half sinusoidal. To provide with the flat field of 10 - 20 #mu#s duration for the multi-turn injection an additional power supply is developed. For the quadrupole magnet a 100 kHz switch-mode power supply is adopted as it requires the fine tuning and accurate field tracking to the dipole field. (author)

2005-06-01

409

Design of a kW, DC Magnetically Contained Electrothermal ...  

Science.gov (United States)

... magnetic containment field lines which is zero on the center line of the toroidal containment tube and increases in magnitude with ...

1988-07-01

410

Combustible Cartridge Case Ballistic Characterization  

Science.gov (United States)

... The combustible cartridge cases currently used by the USArmy in fielded system- are manufactured by two distinct processes. ...

1990-05-01

411

Chiral dynamics of few-nucleon systems  

Energy Technology Data Exchange (ETDEWEB)

I discuss some recent developments in chiral effective field theory for few-nucleon systems.

2008-06-01

412

CORROSION RESISTANCE OF CHROMIUM CARBIDE-BASE ...  

Science.gov (United States)

... FIELD CORROSION TESTS WERE MADE DURING THE VOYAGES OF THE SCIENTIFIC-RESEARCH SHIPS ACADEMICIAN VERNADSKII AND ...

413

A GENERAL STUDY OF PROCESSES FOR THE ...  

Science.gov (United States)

... fields, materials can be subjected to energy densities exceeding those realized in high explosives, a fact which forms the basis for magnetic forming ...

1962-11-01

414

165.37 22,_  

Science.gov (United States)

Aluminum electrolytic capacitors have a long history of reliable operation in unattended field sites. However, their use in the expected space applications ...

415

String field theory-inspired algebraic structures in gauge theories  

International Nuclear Information System (INIS)

We consider gauge theories in a string field theory-inspired formalism. The constructed algebraic operations lead, in particular, to homotopy algebras of the related Batalin-Vilkovisky theories. We discuss an invariant description of the gauge fixing procedure and special algebraic features of gauge theories coupled to matter fields.

2009-06-01

416

Spontaneous radiation decay of weakly bound system in externa field  

International Nuclear Information System (INIS)

A new channel of nonlinear ionization of quantum system in a strong laser field is discussed. The probability of spontaneous radiation decay from the ground state in a short-range potential to the final Volkov wave function, is calculated by the first order of the perturbation theory. It is shown that this process at high intensities of the laser field will be comparable with the high harmonic generation. (orig.)

2001-02-01

417

Serial multivibrator on field effect transistors  

International Nuclear Information System (INIS)

An operating cycle of a serial multivibrator carried out on the base of field-effect transistors has been analyzed. Calculation relations for the main multivibrator parameters have been obtained, and conditions of self-excitation has been determined. Experimental data for determination of the self-oscillation excitation region have been presented. These results are in a good agreement with the experiment. The analysis of the data obtained has shown that the serial multivibrator on field-effect transistors has comparatively narrow excitation region and requires an accurate turning.

418

Second quantization of fields associated with spin-1 tachyons  

Energy Technology Data Exchange (ETDEWEB)

Lorentz invariant theory of second quantization of superluminal electromagnetic fields has been constructed in purely group theoretical manner by using the reduced expansion of four-vector fields for imaginary mass system in terms of standard helicity representations of Poincare group. It has been shown that the usual relationship of spin and statistics need not be inverted for Lorentz invariance of the theory of spin-1 tachyons. 15 refs.

1982-01-01

419

Second quantization of fields associated with spin-1 tachyons  

International Nuclear Information System (INIS)

Lorentz invariant theory of second quantization of superluminal electromagnetic fields has been constructed in purely group theoretical manner by using the reduced expansion of four-vector fields for imaginary mass system in terms of standard helicity representations of Poincare group. It has been shown that the usual relationship of spin and statistics need not be inverted for Lorentz invariance of the theory of spin-1 tachyons. (author).

420

Scanning tip microwave near-field microscope  

Energy Technology Data Exchange (ETDEWEB)

A near-field microscope which operates in the rf/microwave frequency range is described. In this microscope, a scanning tunneling microscope (STM)-like tip rather than an aperture is used as a point-like evanescent field emitter. A spatial resolution of {approximately}5 {mu}m ({approximately}{lambda}/100000) is achieved in the current version. The design of the microscope as well as the principal factors which affect its performance are discussed. {copyright} {ital 1996 American Institute of Physics.}

1996-06-01

421

Preparation of Cluster States for Many Atoms in Cavity QED  

International Nuclear Information System (INIS)

We propose a scheme for the generation of the cluster states for many atoms in cavity QED. In our scheme, the atoms are sent through nonresonant cavity fields in the vacuum states. The cavity fields are only virtually excited and no quantum information will be transferred from the atoms to the cavity fields. The advantage is that the cavities are suppressed during the procedure. The scheme can also be generalized to the ion trap system.

2007-07-15

422

Plasma Flow Equilibrium, Confinement Scaling Laws and Fusion Prospects of a Field Reversed Configuration  

International Nuclear Information System (INIS)

Field reversed configuration (FRC) is a prospective high ? magnetic system for high efficiency D- 3He fusion reactor. Self-consistent FRC plasma profiles and static electric field for reactor calculations are discussed in framework of the model including flow equilibrium and collisionless transport equations. The extrapolations to reactor regimes of plasma confinement scaling laws are considered.

2006-01-01

423

Null field method in wave diffraction problems  

British Library Electronic Table of Contents (United Kingdom)

Diffraction by an impermeable scatterer in ?3 with a Dirichlet boundary condition is considered. It is shown that the null field equation is equivalent to the original diffraction problem. The general theoretical constructions are illustrated by analyzing the excitation of a sphere by a point source. The evolution of the residual of the null field equation as the scatterer surface is approached by an auxiliary surface is estimated.

2011-01-01

424

Methods of reducing magnetic field near the transmission lines  

International Nuclear Information System (INIS)

Due to biological effects of magnetic fields of high voltage transmission lines and induced effects on has pipe line, telecommunication system and interference with sensitive electronic equipment, many effort have been done to reduce transmission lines magnetic fields and several ideas have been introduced. In this paper we review three methods: phase split, shielded and compacted line methods. With aid of a developed software programme these methods are then applied to transmission lines and the results are analyzed.

2003-01-01

425

Main concepts of modern methods for substantiating extractable reserves and coefficients of oil extraction from the depths  

Energy Technology Data Exchange (ETDEWEB)

General conclusions, principles and order of substantiating the extractable reserves and coefficients of oil extraction from oil and oil and gas fields are presented. Recommendations are made for solving questions of constructing calculation models for heterogeneous beds, schematization of the working conditions, selection of mathematical models for oil extraction for different geological-field conditions and different stages of ''life'' of the field.

1984-01-01

426

Local aspects of superselection rules. Pt. 2  

Energy Technology Data Exchange (ETDEWEB)

In a theory where the local observables are determined by local field algebras as the fixed points under a (a priori noncommutative) group of gauge transformations of the first kind, we show that, if the field algebras possess intermediate type I factors, we can construct observables having the meaning of local charge measurements, and local current algebras in the field algebras.

1983-03-01

427

Influence of electric-field is on luminescence of ZnSe  

International Nuclear Information System (INIS)

The results of experimental researches of photoluminescence and X-ray luminescence in crystal ZnSe are presented at the different values of tension of electric-field to samples. Observed, that the electric field changes both intensity of stationary luminescence and form of bars in the spectrums of luminescence. At the saliatory change of difference of potentials on the electrodes of crystal in luminescence there are of long duration relaxation processes character of which substantially depends on the type of excitation of standard.

428

Hybridization and crystal field in YbPd_2Si_2  

International Nuclear Information System (INIS)

Experimental data in the Kondo lattice YbPd_2Si_2 is compared with the results of a hybridization model, based ont he 'large degeneracy expansion' approximation, which takes into account the crystal field level splittings of the Yb ion. We show that satisfactory agreement is obtained with a unique set of crystal field and hybridization parameters. (orig.).

429

Hybridization and crystal field in YbPd sub 2 Si sub 2  

Energy Technology Data Exchange (ETDEWEB)

Experimental data in the Kondo lattice YbPd{sub 2}Si{sub 2} is compared with the results of a hybridization model, based ont he 'large degeneracy expansion' approximation, which takes into account the crystal field level splittings of the Yb ion. We show that satisfactory agreement is obtained with a unique set of crystal field and hybridization parameters. (orig.).

1991-05-01

430

Field-portable lensfree tomographic microscope.  

Science.gov (United States)

We present a field-portable lensfree tomographic microscope, which can achieve sectional imaging of a large volume (?20 mm(3)) on a chip with an axial resolution of Hymenolepis nana egg, which is an infectious parasitic flatworm. Achieving a decent three-dimensional spatial resolution, this field-portable on-chip optical tomographic microscope might provide a useful toolset for telemedicine and high-throughput imaging applications in resource-poor settings. PMID:21573311

2011-05-16

431

Field Investigation of a Wake Structure Downwind of a VAWT (Vertical-Axis Wind Turbine) in a Wind Farm Array.  

Science.gov (United States)

The effects of upwind turbine wakes on the performance of a FloWind 17-m vertical-axis wind turbine (VAWT) were investigated through a series of field experiments conducted at the FloWind wind farm on Cameron Ridge, Tehachapi, California. From the field m...

1988-01-01

432

Feynman rules for gauge fields in the presence of a dielectric medium  

Energy Technology Data Exchange (ETDEWEB)

T. D. Lee's method for developing the Feynman rules for gauge fields in a cavity is reformulated in terms of path integral. His work is then extended by deriving these rules, in the Feynman gauge, for a spherical cavity. In any gauge only the gauge particle propagator is altered, while all the Feynman rules for gauge field couplings are left unaltered by the presence of a dielectric medium.

1983-10-15

433

Extended superconformal algebra from super Toda field theory  

International Nuclear Information System (INIS)

We propose and construct a new type of extended superconformal algebra (ESA) based on the super Toda field theory. Both in the N = 1 ESA and in the N = 2 ESA, an arbitrary value of the central charge is allowed in contrast with the previously known super W-algebra. The generators of ESA are interpreted as the constants of motion in the super Toda field theory. (orig.).

1991-01-01

434

Crystal field in RNiAl compounds studied by inelastic neutron scattering  

Energy Technology Data Exchange (ETDEWEB)

We present a study of the crystal field in PrNiAl, NdNiAl, ErNiAl and ErCuAl intermetallic compounds based on inelastic neutron spectroscopy. These compounds crystallize in the ZrNiAl-type hexagonal structure with an orthorhombic symmetry on rare-earth sites. The results are compared with the specific-heat data, and the lower parts of the crystal-field energy-level schemes are determined. (orig.)

2002-07-01

435

Crystal field in RNiAl compounds studied by inelastic neutron scattering  

International Nuclear Information System (INIS)

We present a study of the crystal field in PrNiAl, NdNiAl, ErNiAl and ErCuAl intermetallic compounds based on inelastic neutron spectroscopy. These compounds crystallize in the ZrNiAl-type hexagonal structure with an orthorhombic symmetry on rare-earth sites. The results are compared with the specific-heat data, and the lower parts of the crystal-field energy-level schemes are determined. (orig.)

2002-01-01

436

Conductance quantization in ferromagnetic Ni nano-constriction  

Energy Technology Data Exchange (ETDEWEB)

The conductance in ferromagnetic Ni nano-wire is quantized in units of 2e{sup 2}/h in the absence of magnetic field, while the units switch to e{sup 2}/h in the magnetic field. The fractional units of 0.7e{sup 2}/h and 1.4e{sup 2}/h with and without magnetic field appear under the application of high bias-voltage. The spin polarization and bias-voltage play an important role in the electric conduction.

2002-02-01

437

Change of crystal field in the Er(Ni,Cu)Al system  

Energy Technology Data Exchange (ETDEWEB)

The ErNi{sub 1-} {sub x} Cu {sub x} Al compounds crystallize all in the hexagonal ZrNiAl-type structure. The concentration dependence of lattice constants shows a discontinuity between x=0.5 and 0.6. This structural change has no primary impact on the magnetic order in this series, but influences the crystal field. The lower part of the crystal-field energy-level schemes has been estimated from the specific-heat data.

2007-09-15

438

Change of crystal field in the Er(Ni,Cu)Al system  

International Nuclear Information System (INIS)

The ErNi_1_- _x Cu _x Al compounds crystallize all in the hexagonal ZrNiAl-type structure. The concentration dependence of lattice constants shows a discontinuity between x=0.5 and 0.6. This structural change has no primary impact on the magnetic order in this series, but influences the crystal field. The lower part of the crystal-field energy-level schemes has been estimated from the specific-heat data.

2007-09-01

439

Calculation of 3-D electrical field distribution around technical devices in the vicinity of high voltage transmission lines  

Energy Technology Data Exchange (ETDEWEB)

The influence that electromagnetic fields have on mechanical and electronic equipment was discussed. A three dimensional numerical simulation model of electric fields around high voltage power transmission lines was described. 4 refs., 1 tab., 5 figs.

1997-12-31

440

Calculation of 3-D electrical field distribution around technical devices in the vicinity of high voltage transmission lines  

International Nuclear Information System (INIS)

The influence that electromagnetic fields have on mechanical and electronic equipment was discussed. A three dimensional numerical simulation model of electric fields around high voltage power transmission lines was described. 4 refs., 1 tab., 5 figs.

1997-08-24

441

Boundary string field theory of the D{bar D} system  

Energy Technology Data Exchange (ETDEWEB)

We develop the boundary string field theory approach to tachyon condensation on the D{bar D} system. Particular attention is paid to the gauge fields, which combine with the tachyons in a natural way. We derive the RR couplings of the system and express the result in terms of Quillen's superconnection. The result is related to an index theorem, and is thus shown to be exact.

2001-05-15

442

Bosonic colored group field theory  

International Nuclear Information System (INIS)

Bosonic colored group field theory is considered. Focusing first on dimension four, namely the colored Ooguri group field model, the main properties of Feynman graphs are studied. This leads to a theorem on optimal perturbative bounds of Feynman amplitudes in the ''ultraspin'' (large spin) limit. The results are generalized in any dimension. Finally, integrating out two colors we write a new representation, which could be useful for the constructive analysis of this type of models. (orig.)

2010-12-01

443

Algebraic description of perturbation theory in quantum electrodynamics  

Energy Technology Data Exchange (ETDEWEB)

An algebraic formulation of the electromagnetic field in which various quantization procedures can be described was chosen to discuss perturbation calculations. It is shown that the Feynman rules and the second order calculation of the self-energy of the electron can be developed on the basis of the Fermi method of quantization. The algebraic approach clarifies the problems in defining the vacuum and other states which are associated with calculations in terms of field algebra operators. It is demonstrated that the vacuum state defined on the field algebra by Schwinger leads to incorrect results in the self-energy calculation.

1982-01-01

444

Acute effects of ELF electromagnetic fields: a field study of linesmen working with 400 kV power lines.  

UK PubMed Central (United Kingdom)

The aim of the study was to investigate the possible acute effects of exposure to electric and magnetic fields. Twenty six experienced linesmen, aged 25 to 52, were studied during two working days while...Full Text Available

1989-10-01

445

Ab initio calculations in a uniform magnetic field using periodic supercells  

Energy Technology Data Exchange (ETDEWEB)

We present a formulation of ab initio electronic structure calculations in a finite magnetic field, which retains the simplicity and efficiency of techniques widely used in first principles molecular dynamics simulations, based on plane-wave basis sets and Fourier transforms. In addition we discuss results obtained with this method for the energy spectrum of interacting electrons in quantum wells, and for the electronic properties of dense fluid deuterium in a uniform magnetic field.

2003-10-21

446

[Comparative study on the historical evolution of field surgery between China and Russia].  

Science.gov (United States)

Russian field surgery with its long history and distinctive characteristics has accumulated great experience in the long-time practice of warfare. Chinese field surgery was established and developed on the basis of studying from the Russian model, which opened up new areas of traffic medicine, molecular traumatology and assessment of biological effects on weapon destruction and carried out in-depth research on wound ballistics, blast injury, burns and combined injury etc. through decades of construction with continuous development and innovation, and a series of major achievements have been made in these fields. By making comparative study on the historical evolution, structure system, characteristics of campaigns and development of society between Chinese and Russian field surgery, it can be found that there are great gaps between them and we should strengthen the research for more rapid development. ...

2010-03-01

447

Why the sunspot cycle is double peaked  

CERN Document Server

Many sunspot cycles are double peaked. In 1967 Gnevyshev suggested that actually all cycles have two peaks generated by different physical mechanisms, but sometimes the gap between them is too short for the maxima to be distinguished in indices of the total sunspot activity. Here we show that indeed all cycles have two peaks easily identified in sunspot activity in different latitudinal bands. We study the double peaks in the last 12 sunspot cycles and show that they are manifestation of the two surges of toroidal field - the one generated from the poloidal field advected all the way on the surface to the poles, down to the tachocline and equatorward to sunspot latitudes, and another one generated from the poloidal field diffused at midlatitudes from the surface to the tachocline and transformed there into toroidal field. The existence of these two surges of toroidal field is due to ...

2011-01-01

448

Tracking failure of gamma-ray irradiated polybutylene polymers under magnetic field  

British Library Electronic Table of Contents (United Kingdom)

Polymer insulating materials used in radioactive environments are subjected to a risk of surface degradation caused by tracking. The tracking behavior becomes more complex with the presence of magnetic field. This paper presents investigation of tracking failure of gamma-ray irradiated polybutylene naphthalate (PBN) and polybutylene terephthalate (PBT) under magnetic field. The samples were irradiated in air up to 100 kGy and then up to 1000 kGy with dose rate of 10 kGy/h by using a 60Co gamma-source. Magnetic field Formula Not Shown with flux density of 250 mT was assembled perpendicularly to electric field Formula Not Shown , which gave rise to relative angle between Formula Not Shown and surface normal vector Formula Not Shown of 0degree, 90degree and 180degree, respectively. The experi...

2011-01-01

449

The Multipoles Factory An Element of the LHC Control  

CERN Document Server

The measurements performed at CERN on prototypes and first pre-series main dipole magnets confirm the need of an active control of the Large Hadron Collider to compensate the dynamic field changes during the proton beam injection and acceleration. This control requires in turn an accurate forecast of the magnetic field in the accelerator. We plan to predict the field on the basis of two elements: theoretical field models tailored through the accumulated knowledge of the main magnets during series tests, and an on-line measurement system running on few reference magnets tracking the LHC current cycle. Data coming from this "Multipoles Factory" will result from the fusion of the two sources. Based on this system we foresee to deliver calibration information for pre-defined accelerator cycles as well as real time information for the active control. In this paper we report the conceptual design of the ...

2002-01-01

450

Stabilizing effect of the electron-beam self-fields on the phase-space trajectory in a self-amplified spontaneous emission free-electron laser operating in ultraviolet and x-ray spectral ranges  

International Nuclear Information System (INIS)

A detailed treatment is introduced to measure the dynamic stability of the relativistic electrons in a self-amplified spontaneous emission free-electron laser (FEL) system, which includes the numerical approach of the Kolmogorov entropy (entropy-like quantity), the general equations of motion for a charged particle and the method of monitoring the simulation accuracy. Numerical experiments reveal a new phenomenon that there exists the possibility of the transition from chaotic to non-chaotic phase-space trajectories of the strongly relativistic electrons due to the effect of their self-fields. The adiabatic magnetic field of a one-dimensional wiggler may have a slight influence on the electron transportation in the absence of the FEL fields, but substantially affects the dynamic stability of the electrons in the process of the FEL interaction. Moreover, the laser fields diminish the dynamic stability of ...

2004-02-28

451

SRS environmental technology development field test platform  

Energy Technology Data Exchange (ETDEWEB)

A critical and difficult step in the development and implementation of new technologies for environmental monitoring and characterization is successfully transferring these technologies to industry and government users for routine assessment and compliance activities. The Environmental Sciences Section of the DOE Savannah River Technology Center provides a forum for developers, potential users, and regulatory organizations to evaluate new technologies in comparison with baseline technologies in a well characterized field test bed. The principal objective of this project is to conduct comprehensive, objective field tests of monitoring and characterization technologies that are not currently used in EPA standard methods and evaluate their performance during actual operating conditions against baseline methods. This paper provides an overview of the field test site and a description of some of the technologies demonstrated at ...

1995-09-01

452

Quantum field theory of particles with braid group statistics in 2+1 dimensions  

CERN Document Server

The present thesis is concerned with the local quantum physics of relativistic particles and fields in three space-time dimensions, whose statistics is to be described by a representation of the braid group -- so-called plektons or, if the representation is Abelian, anyons. In particular the issue of the existence of free anyonic fields is addressed. In our context, these are operators affiliated with the 'local' field algebras and creating only single particle vectors from the vacuum. (Localizability here refers to regions extending to infinity in some spacelike direction.) Under a mild regularity condition for these fields, we can derive commutation relations which are not compatible with braid group statistics. Further, model-independent results concerning the PCT operator and the connection of spin and statistics are obtained. Assuming the observable algebra to satisfy the Bisognano-Wichmann ...

1997-01-01

453

Possible control scenario of radial electric field by loss-cone-particle injection into helical device  

Energy Technology Data Exchange (ETDEWEB)

The possibility of controlling the radial electric field of toroidal plasmas by injecting high energy electrons along the reversible loss cone orbit of the helical magnetic traps is investigated. It is well known that the radial electric field plays an important role in the confinement improvement scenario especially in the low collisional regime under the physics picture of neoclassical theory. For this purpose, it is made clear that the most suitable particles are transit particles, which show a transition from helically trapped orbits to blocked ones. It is also found that a parallel AC electric field launched from outside assists this transition and makes it possible for particles to penetrate deeply into the plasma. In addition we clarify that the viscosity of the plasma coupled with the helical field configuration provide a bifurcation of plasma states and its stable solution results in ...

1999-08-01

454

Non-Gaussian gravitational clustering field statistics  

CERN Document Server

In this work we investigate the multivariate statistical description of the matter distribution in the nonlinear regime. We introduce the multivariate Edgeworth expansion of the lognormal distribution to model the cosmological matter field. Such a technique could be useful to generate and reconstruct three-dimensional nonlinear cosmological density fields with the information of higher order correlation functions. We explicitly calculate the expansion up to third order in perturbation theory making use of the multivariate Hermite polynomials up to sixth order. The probability distribution function for the matter field includes at this level the two-point, the three-point and the four-point correlation functions. We use the hierarchical model to formulate the higher order correlation functions based on combinations of the two-point correlation function. This permits us to find compact expressions for the skewness and ...

2010-01-01

455

New Lectures on Supergravity  

CERN Document Server

This essay aims to summarize the main physical features arising from a new supersymmetric theory of gravitation. Based on preliminary discussions about classical field theory, cosmology, algebra and group theory, and taking formal results and theoretical considerations in comparison with several contributions from great authors, present work deals with gravity inside the limits of a meta-field theory, that is, a non-quantized but consistent representation of supergravity, the supersymmetry between gravitons and gravitinos. The introduction of meta-fields furnishes an independent framework for the study of gravity despite of constraints of quantization, treating the supersymmetric partners as deterministic actors of gravitation and not simply probabilistic entities. I explain my belief that gravitational field, by its own nature, is not quantizable in the same foot as the other ...

2011-01-01

456

Magnetocaloric and magnetoresistance studies of GdPd{sub 2}Si  

Energy Technology Data Exchange (ETDEWEB)

The compound GdPd{sub 2}Si, which is reported to order antiferromagnetically at 13 K, has been investigated by heat capacity and electrical resistivity measurement in the presence of external magnetic fields. In contrast to an earlier report, the zero-field heat capacity and resistivity data indicate two magnetic transitions at 13 and 17 K. The external magnetic field substantially influences the resistivity and heat capacity of the compound around the magnetic ordering temperature. The magnetocaloric effect, which is calculated from in-field heat capacity data, is quite large around the magnetic transition temperature. The magnetoresistance is also large near the magnetic ordering temperature. The metamagnetic transition is observed for 10 kOe magnetic field both in magnetocaloric and in magnetoresistance data. The metamagnetic transition strongly influences the magnetocaloric ...

2001-01-22

457

Magnetocaloric and magnetoresistance studies of GdPd_2Si  

International Nuclear Information System (INIS)

The compound GdPd_2Si, which is reported to order antiferromagnetically at 13 K, has been investigated by heat capacity and electrical resistivity measurement in the presence of external magnetic fields. In contrast to an earlier report, the zero-field heat capacity and resistivity data indicate two magnetic transitions at 13 and 17 K. The external magnetic field substantially influences the resistivity and heat capacity of the compound around the magnetic ordering temperature. The magnetocaloric effect, which is calculated from in-field heat capacity data, is quite large around the magnetic transition temperature. The magnetoresistance is also large near the magnetic ordering temperature. The metamagnetic transition is observed for 10 kOe magnetic field both in magnetocaloric and in magnetoresistance data. The metamagnetic transition strongly influences the magnetocaloric effect ...

2001-01-22

458

Introduction to symmetry and supersymmetry in quantum field theory  

Energy Technology Data Exchange (ETDEWEB)

This is a set of lecture notes given by the author at the Universities of Gottingen and Wroclaw. The text presents the axiomatic approach to field theory and studies in depth the concepts of symmetry and supersymmetry and their associated generators, currents and charges. It is intended as a one- semester course for graduate students in the field of mathematical physics and high energy physics. Contents: Introduction; Example of a Classical and Quantum Scalar Free Field Theory; Scene and Subject of the Drama. Axiom 1 and 2; Subject of the Drama; Principle of Relativity. Causality. Axiom 3, 4 and 5; Irreducibility of the Field Algebra and Scattering Theory. Axiom 6. Axiom O; Preliminaries about Physical Symmetries; Currents and Charges; Global Symmetries and Supersymmetries of the S - Matrix; Representations of the Super-Lie Algebra; The Case of Massless Particles; Fermionic Charges; Concluding Remarks.

1988-01-01

459

Floating production systems gain favour  

Energy Technology Data Exchange (ETDEWEB)

The use of Floating Production Storage and Offloading (FPSO) vessels to develop UK offshore oil fields looks certain to increase. Of the 64 new offshore fields due for development in the next few years, 15 are expected to use FPSO vessels for their production. Most of these are small, short-life fields in the central North Sea which would not justify investment in a fixed platform. Three, however, are large fields west of Shetland, and one, the Foinaven field, is scheduled to be the first commercial development in this area, perhaps setting a precedent. Floating production systems with substantial storage capacity can be the best option in deepwater locations which are remote from existing infrastructure, where the cost of an export pipeline would be prohibitive. (author)

1995-09-01

460

Field-induced valence transition of Eu(Pd_1_-_xPt_x)_2Si_2  

International Nuclear Information System (INIS)

The magnetic susceptibility and high-field magnetization have been measured for the intermediate valence system Eu(Pd_1_-_xPt_x)_2Si_2 with 0#<=#x#<=#0.15. A first-order valence transition is observed for all the compounds under high field of 100 T at low temperatures. This valence transition is of first order accompanied with a large hysteresis, which is in contrast to a continuous valence change against temperature. Based on the interconfigurational fluctuation (ICF) model, the temperature- and field-induced valence transitions are discussed. It is found that a first-order valence transition can be induced by magnetic field, even if the system shows a continuous valence transition against temperature. Metamagnetic behavior at finite temperatures is also understood qualitatively by the ICF model. copyright 1997 The American Physical Society.

461

Environmental and health effects of electric and magnetic fields from transmission lines  

Energy Technology Data Exchange (ETDEWEB)

Concerns are sometimes expressed about an alleged link between exposure to the extremely low frequency electromagnetic fields occurring in proximity to electricity networks or equipment. Transmission lines are specifically mentioned. The underlying physical mechanisms are described by which electric and magnetic fields exist, with particular reference to high voltage transmission lines. Epidemiological and laboratory studies are the two approaches used in research into the subject and the shortcomings inherent in many such studies and the inconsistencies in the results are mentioned. Some of the more recent epidemiological studies are referred to, also the possible interaction mechanisms between fields and the human body. The work of certain international and national bodies which were established to review the results of research into the alleged association between electromagnetic fields and ...

1996-12-31

462

Electronic structures of organometallic complexes of f elements. XLIV. Parametrization of the crystal field splitting pattern of [(MeCp)_3PrCl]"-  

International Nuclear Information System (INIS)

The absorption and magnetic circular dichroism spectra of [N(n-Bu)_4]"+[(MeCp)_3PrCl]"- dissolved in 2-MeTHF were measured at room and at low temperatures. On the basis of these spectra the crystal field splitting pattern could be derived. The parameters of an empirical Hamiltonian were fitted to the energies of 42 levels to give an r.m.s. deviation of 23 cm"-"1. From the crystal field parameters obtained the crystal field strength of the ligand collective was estimated. Compared with neutral Cp_3Pr circle B complexes the crystal field strength of the anionic [(MeCp)_3PrCl]"- moiety is unusually low. (orig.)

1998-07-24

463

Effect of the induced magnetic field on peristaltic flow of a couple stress fluid  

Science.gov (United States)

We have analyzed the MHD flow of a conducting couple stress fluid in a slit channel with rhythmically contracting walls. In this analysis we are taking into account the induced magnetic field. Analytical expressions for the stream function, the magnetic force function, the axial pressure gradient, the axial induced magnetic field and the distribution of the current density across the channel are obtained using long wavelength approximation. The results for the pressure rise, the frictional force per wave length, the axial induced magnetic field and distribution of the current density across the channel have been computed numerically and the results were studied for various values of the physical parameters of interest, such as the couple stress parameter ?, the Hartmann number M, the magnetic Reynolds number R and the time averaged mean flow rate ?. Contour plots for the stream and magnetic force functions are obtained and ...

2008-06-01

464

Coupling of magnetostriction and electrostriction in the porous rheological composite  

Energy Technology Data Exchange (ETDEWEB)

The production method of the elastic composite containing ferrous particles and titanium barium particles dispersed in the porous silicone matrix is described in this article. Since it contains ferrous and titanium barium particles, this composite shows magnetorheological and also electrorheological properties. The electrostriction of composite samples in the electric field with maximal intensity 1.5x10{sup 6} V/m was investigated. The magnetostriction in the magnetic field with maximal induction 1 T was also investigated. It was found that samples elongate with increased electric field intensity, and the magnetic field induction was detected. By increasing the samples' elongation with increase of ferrous particles, titanium barium particles and pores number were also detected. In the investigated division of the electric and magnetic field the elongation changed in a ...

2008-08-15

465

Biological effects and physical safety aspects of NMR imaging and in vivo spectroscopy  

Energy Technology Data Exchange (ETDEWEB)

An assessment is made of the biological effects and physical hazards of static and time-varying fields associated with the NMR devices that are being used for clinical imaging and in vivo spectroscopy. A summary is given of the current state of knowledge concerning the mechanisms of interaction and the bioeffects of these fields. Additional topics that are discussed include: (1) physical effects on pacemakers and metallic implants such as aneurysm clips, (2) human health studies related to the effects of exposure to nonionizing electromagnetic radiation, and (3) extant guidelines for limiting exposure of patients and medical personnel to the fields produced by NMR devices. On the basis of information available at the present time, it is concluded that the fields associated with the current generation of NMR devices do not pose a significant health risk in themselves. However, rigorous guidelines must be ...

1985-08-01

466

Bianchi type IX brane-world cosmologies  

International Nuclear Information System (INIS)

We investigate the asymptotic properties of the Bianchi type IX cosmological model in the brane-world scenario. The matter content is assumed to be a combination of a perfect fluid and a minimimally coupled scalar field that is restricted to the brane. A detailed qualitative analysis of the Bianchi type IX brane-world containing a scalar field having an exponential potential is undertaken. It is found that the brane-Robertson-Walker solution is a local source for the expanding Bianchi type IX models, and if k"2<2 the ever-expanding Bianchi IX models asymptote to the power-law inflationary solution. The only other local sink is the contracting brane-Robertson Walker solution. An analysis of the Bianchi type IX models with a scalar field with a general potential is discussed, and it is shown that in the case of expanding models, for physical scalar field potentials close to the initial singularity, the ...

2003-07-15

467

Application of GIS for the evaluation of human exposure to magnetic field in the vicinity of power lines  

Energy Technology Data Exchange (ETDEWEB)

Application of the Geographic Information System (GIS) with a statistical model to evaluate the magnetic field exposure of a population from high-voltage transmission lines near residential areas is discussed, focusing on the interaction of the GIS with the statistical model. In an effort to validate the model measurements of the magnetic field, profiles were taken at two sites and these profiles have been compared with calculated values. Two conclusions have been drawn from the results: (1) the statistical model linked with the GIS is a very powerful tool for the evaluation of exposure of a population to magnetic fields, and (2) success depends on the presence of other sources of magnetic fields and on the exactness of the data used in the model. 4 refs., 5 figs.

1998-10-01

468

A soft x-ray free electron laser (FEL) using a two-beam elliptical pill-box wake-field cavity  

International Nuclear Information System (INIS)

Stimulated bremsstrahlung in an undulating electric field in the lasing beam direction (electric wiggler) was shown to be possible from the quantum- mechanical viewpoint. Herein, this possibility is scrutinized from the viewpoint of classical electrodynamics. It is found that if stimulated bremsstrahlung in a transverse undulating magnetic field (magnetic wiggler) occurs, stimulated bremsstrahlung in the electric wiggler must also occur. We further show that a free electron laser (FEL) using a magnetic wiggler to provide a catalyzer field for stimulated bremsstrahlung cannot serve as a practical FEL operating in the soft x-ray region from both theoretical and experimental viewpoints. On the other hand, the authors demonstrate that the FEL using a traveling wake field in a two-beam elliptical pill-box cavity is well suited as a source of coherent radiation in the soft x-ray region.

1988-01-14

469

Time-varying magnetic fields increase cytosolic free Ca sup 2+ in HL-60 cells  

Energy Technology Data Exchange (ETDEWEB)

Electromagnetic fields have been reported to cause a variety of biological effects. It has been hypothesized that many of these phenomena are mediated by a primary effect on the concentration of cytosolic free calcium ((Ca2+)i). We investigated the effects of exposure to electromagnetic fields on (Ca2+)i in HL-60 cells using the Ca2(+)-sensitive fluorescent indicator indo-1. Indo-1-loaded cell samples were exposed to a radiofrequency electromagnetic field, a static magnetic field, and a time-varying magnetic field, which were generated by a magnetic resonance imaging (MRI) unit. We found that a 23-min exposure to all three fields, in combination, induced a significant increase in (Ca2+)i of 31 +/- 8 (SE) nM (P less than 0.01, n = 13) from a basal level of 121 +/- 8 nM. Also, cells exposed to only the time-varying magnetic field had a mean ...

1990-10-01

470

Treatment of low-frequency pulsating magnetic field on amorphous alloy Fe_7_8Si_9B_1_3  

International Nuclear Information System (INIS)

Effect of low-frequency pulsating magnetic field on the microstructure and magnetic properties of amorphous alloy Fe_7_8Si_9B_1_3 were investigated. The temperature rise induced by the treatment was measured by a non-contact infrared thermometer. The crystallization behavior and microstructure of specimens were studied by Moessbauer spectroscopy and transmission electron microscope (TEM). Magnetic properties of the specimens were investigated by alternating gradient magnetometer (AGM). The results show that the low-frequency pulsating magnetic field can promote the single-phase crystallization of amorphous alloy Fe_7_8Si_9B_1_3. The frequency, f of applied field is from 10 to 40 Hz, magnetic field, H is from 0.02 to 0.04 T and treatment duration, t is from 180-300 s. The volume fraction of crystallization phase (#alpha#-Fe(Si), the grain size, 2-10 nm) is 3-7%. The temperature rise less than 7 deg. C. ...

2007-07-15

471

Spontaneous Radiation Emission from Short, High Field Strength Insertion Devices  

Energy Technology Data Exchange (ETDEWEB)

Since the earliest papers on undulaters were published, it has been known how to calculate the spontaneous emission spectrum from ''short'' undulaters when the magnetic field strength parameter is small compared to unity, or in ''single'' frequency sinusoidal undulaters where the magnetic field strength parameter is comparable to or larger than unity, but where the magnetic field amplitude is constant throughout the undulater. Fewer general results have been obtained in the case where the insertion device is both short, i.e., the magnetic field strength parameter changes appreciably throughout the insertion device, and the magnetic field strength is high enough that ponderomotive effects, radiation retardation, and harmonic generation are important physical phenomena. In this paper a general method is presented ...

2005-09-15

472

Reducing magnetic fields. Magnetic fields of high-voltage transmission lines or in residential buildings can be largely reduced; Magnetische Felder reduzieren. Bei Hochspannungsleitungen und in Wohnungen lassen sich magnetische Felder weitgehend kompensieren  

Energy Technology Data Exchange (ETDEWEB)

Magnetic fields can be compensated by opposing fields. This principle can be applied for reducing the magnetic fields emanating from high-voltage transmission lines or found in residential or commercial buildings. The article shows a number of concrete options for reducing magnetic fields in the vicinity of high-voltage lines through appropriate conductor configuration on the one hand, and a novel method using Helmholtz coils for compensating those fields in buildings. (orig.) [Deutsch] Magnetische Felder koennen durch Gegenfelder kompensiert werden. Dieses Prinzip laesst sich sowohl auf Hochspannungsleitungen als auch auf Wohn- und Arbeitsraeume uebertragen. Der Artikel zeigt konkrete Moeglichkeiten, wie einerseits Magnetfelder von Hochspannungsleitungen durch eine geeignete Konfiguration der Leiter reduziert werden koennen, und beschreibt andererseits eine neue Methode zur ...

1997-10-17

473

Electromagnetic radiation unmasked  

International Nuclear Information System (INIS)

This article describes the nature of the electromagnetic waves, what they are and how do they affect us. Current concern is focused on exposure to low level power-frequency magnetic fields like microwave radiation from mobile phones and leaking microwave ovens; high power radiation from defence and airport radars; fields close to high voltage transmission lines; radio frequency fields from industrial welders and heaters and DC magnetic fields in aluminium smelters. These fields with frequency less than 300 GHz do not carry sufficient energy to break chemical bonds and it is assumed that they cannot damage cell DNA. The amount of radiation absorbed by a human exposed to far field electromagnetic radiation (EMR) depends on the orientation and size of the person. In the 30-300 MHz range it is possible to excite resonance in the whole or partial body such as the ...

1996-01-01

474

Density separation of materials by using magnetic fluids  

Energy Technology Data Exchange (ETDEWEB)

The magnetic fluid is a colloidal suspension of magnetite in kerosene, prepared by a low-cost process. Separation is accomplished in an open trough filled with magnetic fluid. A magnetic field is established in the fluid, by energizing an electromagnet having poles on each side of the trough. Due to the design of the magnet poles and air gaps, the magnetic field is strongest at the bottom, about 10,000 oersteds, and uniformly decreases in strength to about 2000 oersteds at the top of the fluid. Therefore, the magnetic field gradient increases with depth. The magnetic force attracts the entire separation medium (magnetic fluid) creating a reaction force of equal magnitude and acting in the opposite direction. This reaction created within a magnetic fluid/magnetic field combination is called a magnetic levitation force. It increases with the field strength. In this case because the ...

1980-03-01

475

Final technical report for ''Frontiers in Plasma Kinetic Theory''  

International Nuclear Information System (INIS)

This report summarizes the results and activities funded by this three-year award. The principal goal of this project was to determine the thermal conductivity in clusters of galaxies. Intracluster plasmas possess chaotic magnetic fields. Since charged particles are constrained to move primarily along magnetic field lines, the topology of intracluster magnetic fields slows particle diffusion relative to the non-magnetized case, thereby reducing the thermal conductivity. Our first approach to this problem was to employ the static-magnetic-field approximation. In reality, intracluster magnetic field lines are constantly moving, since they are advected by turbulent intracluster motions. The turbulent velocities, however, are much smaller than the rapid speeds of thermal electrons, which make the dominant contribution to the thermal conductivity. In the static-field ...

2007-02-01

476

Success in geothermal development  

International Nuclear Information System (INIS)

Success in geothermal development can be defined as the ability to produce geothermal energy at compatible energy prices to other energy sources. Drilling comprises usually the largest cost in geothermal development, and the results of drilling is largely influencing the final price of geothermal energy. For 20 geothermal fields with operating power plants, the ratio between installed capacity and the total number of well in the field is 1.9 MWe/well. The drilling history in 30 geothermal fields are analyzed by plotting the average cumulative well outputs as function of the number of wells drilled in the field. The range of the average well output is 1-10 MWe/well with the mean value 4.2 MWe/well for the 30 geothermal fields studied. A leaning curve is defined as the number of wells drilled in each field before the average output per well reaches a fairly ...

477

Numerical ray tracing of electrons in different 3D fringing fields of spherical deflectors  

Science.gov (United States)

This paper presents the results of numerical investigations on electron trajectories in different 3D fringing fields of spherical defectors. We start with a chosen set of geometrical values for the electrodes such as radius of curvature, electrode gap, angle between entrance and exit face. We do a first numerical calculation of the spatial potential distribution using a 3D electron optics program based on the finite difference method (FDM). Ray tracing through this potential distribution is then performed using another program, which also gives the potential and the electric field strength along the curved beam path. In the next step we estimate the position and the geometry of the field clamp using Herzog's formulae assuming the entrance of a parallel plate condenser to be a good approximation for the entrance of the spherical deflector in first order. For the consecutive numerical recalculations of the real potential ...

1999-11-01

478

Heat transfer augmentation using a magnetic fluid under the influence of a line dipole  

Energy Technology Data Exchange (ETDEWEB)

Ferrofluids have promising potential for heat transfer applications, since advective transport in a ferrofluid can be readily controlled by using an external magnetic field. However, unlike conventional free or forced convection, ferrohydrodynamic convection is not yet well characterized. A full understanding of the relationship between an imposed magnetic field, the resulting ferrofluid flow, and the temperature distribution is a prerequisite for the proper design and implementation of applications involving thermomagnetic convection. The literature variously assumes constant magnetic fields, does not completely represent the variation in the imposed field, or its descriptions are inaccurate, since the fields do not comply with the Maxwell's equations of electromagnetism. We address this by simulating two-dimensional forced convection heat transfer in a channel with a ...

2004-04-01

479

Heat transfer augmentation using a magnetic fluid under the influence of a line dipole  

International Nuclear Information System (INIS)

Ferrofluids have promising potential for heat transfer applications, since advective transport in a ferrofluid can be readily controlled by using an external magnetic field. However, unlike conventional free or forced convection, ferrohydrodynamic convection is not yet well characterized. A full understanding of the relationship between an imposed magnetic field, the resulting ferrofluid flow, and the temperature distribution is a prerequisite for the proper design and implementation of applications involving thermomagnetic convection. The literature variously assumes constant magnetic fields, does not completely represent the variation in the imposed field, or its descriptions are inaccurate, since the fields do not comply with the Maxwell's equations of electromagnetism. We address this by simulating two-dimensional forced convection heat transfer in a channel with a ferrofluid ...

2004-04-01

480

Why there is a field algebra with a compact gauge group describing the superselection structure in particle physics  

International Nuclear Information System (INIS)

Given the local observables in the vacuum sector fulfilling a few basic principles of local quantum theory, we show that the superselection structure, intrinsically determined a priori, can always be described by a unique compact global gauge group acting on a field algebra generated by field operators which commute or anticommute at spacelike separations. The field algebra and the gauge group are constructed simultaneously from the local observables. There will be sectors obeying parastatistics, and intrinsic notion derived from the observables, if and only if the gauge group is non-Abelian. Topological charges would manifest themselves in field operators associated with spacelike cones but not localizable in bounded regions of Minkowski space. No assumption on the particle spectrum or even on the covariance of the theory is made. However the notion of superselection sector is tailored to theories ...

1990-01-01

481

Test Bed for Superconducting Materials  

Energy Technology Data Exchange (ETDEWEB)

Superconducting rf cavities are increasingly used in accelerators. Gradient is a parameter of particular importance for the ILC. Much progress in gradient has been made over the past decade, overcoming problems of multipacting, field emission, and breakdown triggered by surface impurities. However, the quenching limit of the surface magnetic field for niobium remains a hard limitation on cavity fields sustainable with this technology. Further exploration of materials and preparation may offer a path to surpassing the current limit. For this purpose, we have designed a resonant test cavity. One wall of the cavity is formed by a flat sample of superconducting material; the rest of the cavity is copper or niobium. The H field on the sample wall is 75% higher than on any other surface. Multipacting is avoided by use of a mode with no surface electric field. The cavity will be resonated ...

2006-01-30

482

Roles of bumpy field on collisionless particle confinement in helical-axis heliotrons  

Energy Technology Data Exchange (ETDEWEB)

Roles of bumpy field on collisionless particle confinement in helical-axis heliotrons are investigated with the model magnetic field and particle orbit calculations in the Boozer coordinates. The mod-B{sub min} contours can be shifted in the major radius direction with the control of the bumpy field, where B{sub min} is the minimum value of |B| in the toroidal direction within one field period. The area of closed mod-B{sub min} contours is a useful measure to evaluate global collisionless particle confinement as long as the mod-B{sub min} contours connect toroidally. Negative value of ratio between the bumpy and the helicity components contributes to obtain the largest area of closed mod-B{sub min} contours for finite ratio between the toroidicity and the helicity components. The radial variation of the bumpy field attributes to realize a toroidally localized mod-B{sub min} ...

1999-02-01

483

On higher derivative corrections of tachyon action  

Energy Technology Data Exchange (ETDEWEB)

We have examined the momentum expansion of the disk level S-matrix element of two tachyons and two gauge fields to find, up to on-shell ambiguity, the couplings of these fields in the world volume theory of N coincident non-BPS D-branes to all order of {alpha}'. Using the proposal that the action of D-brane-anti-D-brane is given by the projection of the action of two non-BPS D-branes with (-1){sup F{sub L}}, we find the corresponding couplings in the world volume theory of the brane-anti-brane system. Using these infinite tower of couplings, we then calculate the massless pole of the scattering amplitude of one RR field, two tachyons and one gauge field in the brane-anti-brane theory. We find that the massless pole of the field theory amplitude is exactly equal to the massless pole of the disk level S-matrix element of one RR, two tachyons and one gauge ...

2008-09-11

484

Magnetic field amplification and generation in hypervelocity meteoroid impacts with application to lunar paleomagnetism  

International Nuclear Information System (INIS)

A one-dimensional numerical model for the expansion of impact-produced vapor clouds is used to investigate magnetic field generation mechanisms in events such as meteor collisions with the moon. The resulting cloud properties, such as ionization fraction, electrical conductivity, radial expansion velocity, mass density, and energy density are estimated. The model is initiated with the peak shock states and pressure thresholds for incipient and complete vaporization of anorthosite lunar surface materials by iron and GA composition meteorites. The expansion of the spherical gas cloud into a vacuum was traced with a one-dimensional explicit lagrangian hydrodynamic code. The hypervelocity impact plasmas produced are found to be significant in the amplitudes and orientations of the magnetic fields generated. An ambient magnetic field could have been provided by the core dynamo, which would have interacted with the expanding ...

1984-03-12

485

Free electron laser experiments using a long pulse induction linac  

International Nuclear Information System (INIS)

The NRL Long Pulse Induction Linac is being employed in a Free Electron Laser (FEL) experiment. The authors present results of beam transport and focusing experiments as well as measurements of the output radiation generated by various magnetic wigglers. The electron gun of the accelerator presently has a 17-cmdiam. cold cathode which is located in a nearly zero magnetic field (B /SUB z/ less than or equal to 5 G). The gun voltage is flat to within approx. = + or - 5% for 1.5 #mu#sec with this graphite brush cathode. The beam is focused by a series of solenoidal coils as it propagates through the 4-m-long accelerator."2 A solenoidal field which can be varied from 1-10 kG confines the beam in the FEL interaction region. Previous experiments were limited by poor beam transport, focusing, and matching into the relatively large solenoidal field in the FEL region. By smoothing the axial magnetic field ...

486

Free electron laser and accelerator  

International Nuclear Information System (INIS)

The present report addresses several aspects of the free electron laser (FEL) and accelerator, including their features, potentials, mechanisms, beams emitted from undulator, FEL produced by helical mangnetic field, major problems with FEL, etc. In FEL, relativistic electron beams interact with an electromagnetic field with periodically changing intensity to produce coherent electromagnetic waves with variable wavelength. The capability of varying its wavelength represents the greatest advantage over conventional lasers. Any periodic magnetic field can serve as a wiggler. A wiggler can be used both in an amplifier and oscillator. A periodic magnetic field used may be either of a parallel type or of a helical type. The polarization of emitted beams depends on the shape of the magnet regardless of whether its field is parallel or helical. An equation is derived in the report which ...

1988-08-01

487

Feasibility study of large combined function magnets for the Jefferson lab 12 GeV upgrade  

CERN Document Server

The 12 GeV upgrade at Jefferson Lab has identified two new large spectrometers as Physics detectors for the project. The first is a 7.5 Gev/c 35 m-sr. spectrometer that requires a pair of identical Combined Function Superconducting Magnets (CFSM) that can simultaneously produce 1.5 T dipole fields and 4.5 T/m quadrupole fields inside a warm bore of 120cm. The second is an 11 GeV/c 2 m-sr. spectrometer that requires a CFSM that simultaneously produces a dipole field of 4.0 T and a quadruple field of 3.0 T/m in a 60 cm warm bore. Magnetic designs using TOSCA 3D have been performed to realize the magnetic requirements, provide 3d fields for optics analysis and produce field and force information for the engineering feasibility of the magnets. A two-sector cos( theta )/cos(2 theta ) design with a low nominal current density, warm bore and warm iron design has been ...

2005-01-01

488

Electromagnetic fields and cancer: how ICNIRP has dealt with the issue  

International Nuclear Information System (INIS)

Whether exposure to electromagnetic fields (EMFs) cause cancer has been vigorously debated for many years and has been the most vexing issue with which ICNIRP has had to deal during its short existence. There have been three parts of the electromagnetic spectrum that the issue of cancer has raised: static (0 Hz) magnetic fields, extremely low frequency (ELF) fields (defined as > 0-300 Hz, but concerns have been raised almost exclusively at the power frequencies of 50/60 Hz), and radiofrequency (RF) fields (300 Hz -300 GHz). By far the major problems have arisen during the construction of new high voltage transmission lines and mobile telephone systems. Actions by protest groups concerned with possible health effects, especially with cancer in children, has now reached such a scale that it is costing electrical utilities and communications companies billions of dollars annually world-wide. With such ...

1996-04-01

489

Design of modular coils for a quasi-axisymmetric stellarator with a flexible control of the magnetic field configuration  

Energy Technology Data Exchange (ETDEWEB)

A design of the modular coil system for CHS-qa has been made for the plasma configuration '2b32' with the aspect ratio 3.2. The magnetic field strength and the major radius are 1.5 T and 1.5 m, respectively. The normal component of magnetic field produced by the modular coils is minimized on the plasma boundary to obtain the optimum coil design. We put engineering constraint on the distance between adjacent modular coils and the radius of coil curvature. The dependence of the residual normal component of the field on these conditions is examined, and the realistic values for them are selected. Additional coils to control various properties of the magnetic field configuration (the rotational transform, the magnetic well depth, etc.) have been designed and a flexibility of the magnetic field configuration is realized. For the case that the rotational transform ...

2002-08-01

490

Design and experimental results on a terawatt magnetically controlled plasma opening switch  

Energy Technology Data Exchange (ETDEWEB)

The magnetically controlled plasma opening switch (MCPOS) is an advanced plasma opening switch that utilizes magnetic fields to improve operation. Magnetic fields always dominate terawatt, pulsed power plasma opening switches. For that reason, the MCPOS uses controlled applied magnetic fields with magnitude comparable to the self-magnetic field of the storage inductor. One applied field holds the plasma in place while energy accumulates in the storage inductor, then another applied field pushes the plasma away from the cathode to allow energy to flow downstream. Over a ten month period, an MCPOS was designed, built, and tested on DECADE Module 2 at Physics International. The peak drive current was 1.8 MA in 250 ns. The output parameters were up to 1 MA into an electron beam load. The radiation temporal pulse width averaged 60 nanoseconds full-width at ...

1998-05-01

491

The electronic structure of organometallic complexes of the f elements XXV. Crystal field splitting pattern of the anionic complex [Cp_3Pr. NCS]"-  

International Nuclear Information System (INIS)

The absorption, emission and magnetic circular dichroism spectra of the anionic complex (Cp_3Pr. NCS)"- were measured at room and low temperatures. On the basis of these spectra the electronic structure in the f-f range could be derived. The parameters of an empirical Hamiltonian were fitted to the experimentally determined crystal field splitting pattern. Compared with the previously examined neutral Cp_3 Pr.X complexes the quadratic crystal field parameter B_0"2 is considerably reduced.

492

Spontaneous radiation and lamb shift in three-dimensional photonic crystals  

Science.gov (United States)

Spontaneous emission in photonic crystals with anisotropic three-dimensional dispersion relation is studied. If the upper level is below a characteristic frequency omega(1), or above omega(2), or between omega(1) and omega(2), the radiation is a localized field with a frequency in the band gap, or a propagating field with a frquency in the band, or a diffusion field, respectively. An analytical expression for the Lamb shift is obtained. The Lamb shift for the current case is small compared to that in an ordinary vacuum or in one- or two-dimensional photonic crystals due to lower density of states. PMID:11017227

2000-03-01

493

Some physical considerations in whole skin electron beam therapy  

Energy Technology Data Exchange (ETDEWEB)

The short range of low-energy electrons has made them suitable for the treatment of skin lesions, especially when extensive areas must be irradiated with special considerations to save the normal underlying tissue. This report covers some salient features of total body electron irradiation: the construction of the large fields required, x-ray contamination levels, and multiple-field techniques. While the investigation is essentially experimental, we also indicate the results of calculations. We conclude most generally that treatment planning with whole skin irradiations can be as precise as with smaller fields.

1982-09-01

494

Possibility of internal transport barrier formation and electric field bifurcation in LHD plasma  

Energy Technology Data Exchange (ETDEWEB)

Theoretical analysis of the electric field bifurcation is made for the LHD plasma. For given shapes of plasma profiles, a region of bifurcation is obtained in a space of the plasma parameters. In this region of plasma parameters, the electric field domain interface is predicted to appear in the plasma column. The reduction of turbulent transport is expected to occur in the vicinity of the interface, inducing a internal transport barrier. Within this simple model, the plasma with internal barriers is predicted to be realized for the parameters of T{sub e}(0) {approx} 2 keV and n(0) {approx_equal} 10{sup 18} m{sup -3}. (author)

1999-05-01

495

Optical pressure on thin film caused by a Gaussian beam-generated evanescent wave  

International Nuclear Information System (INIS)

The optical pressure exerted o a thin film, which is locked in the evanescent field formed at the plane interface with a totally-reflected Gaussian beam, is investigated. Some calculations of the pressure on the film caused by the evanescent field are presented in the different conditions of film thickness, film position, incident angle and polarization of a gaussian beam. The results show that the pressure exertion on the thin film can change from pushing to pulling as the parameters are varied. In particular, we find that the direction of optical pressure can act oppositely at the different positions of the film surface in the evanescent field.

1994-11-01

496

Numerical study of Cosmic Ray Diffusion in MHD turbulence  

CERN Document Server

We study diffusion of Cosmic Rays (CRs) in turbulent magnetic fields using test particle simulations. Electromagnetic fields are produced in direct numerical MHD simulations of turbulence and used as an input for particle tracing, particle feedback on turbulence being ignored. Statistical transport coefficients from the test particle runs are compared with earlier analytical predictions. We find qualitative correspondence between them in various aspects of CR diffusion. In the incompressible case, that we consider in this paper, the dominant scattering mechanism occurs to be the non-resonant mirror interactions with the slow-mode perturbations. Perpendicular transport roughly agrees with being produced by magnetic field wandering.

2010-01-01

497

Novel triangle relation and absence of tachyons in Liouville string field theory  

International Nuclear Information System (INIS)

We construct the quantum mechanical field operator of the two-dimensional Liouville theory in a finite box. This leads us to the discovery of a new type of triangle relation which does not reduce to the already known ones. We apply our result to the construction of the string model in an arbitrary number of space-time dimensions D. We show that there are no tachyons in -infinite1, which is a strong-coupling region for the Liouville field theory. (orig.).

498

Correlation between Magnetic Field Quality and mechanical components of the Large Hadron Collider Main Dipoles  

CERN Document Server

The homogeneity of the magnetic field in the LHC dipoles strongly depends on the correct position of the superconducting cables: this is related to the quality of the dipole components, such as the dimension of the coil spacers (copper wedges), of the cable and of the collars. The performance in operational conditions is also affected by the magnetization of the cables. In this work, we analyse the measurements of these quantities during the production of the 1276 LHC dipoles, their trends, and the relation to the measured magnetic field. A novel mtehod to locate electrical shorts based on the analysis of magnetic measurements is also presented, and applications to 15 dipoles reascued during the production is given.

2006-01-01

499

Closed string tachyons and their implications for non-supersymmetric strings  

Energy Technology Data Exchange (ETDEWEB)

Closed string tachyons have long been somewhat mysterious. We note that there is often a regime in the classical moduli space in which one can systematically compute the effective action for such fields. In this regime, the tachyon is light, and cannot be integrated out. Instead, one must consider the combined dynamics of gravitons, moduli, tachyons and other light fields. We compute the action and find that the quartic term for the tachyon is positive in the field definition where the tachyon has no derivative coupling to the radion. We study the evolution of isotropic, homogeneous configurations and find that typically the system is driven to regions where the calculation is no longer under control. (author)

2004-07-01