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Many solutions of General Relativity appear to allow the possibility of time travel. This was initially a fascinating discovery, but geometries of this type violate causality, a basic physical law which is believed to be fundamental. Although string theory is a proposed fundamental theory of quantum gravity, geometries with closed timelike curves have resurfaced as solutions to its low energy equations of motion. In this paper, we will study the class of solutions to low energy effective supergravity theories related to the BMPV black hole and the rotating wave-D1-D5-brane system. Time travel appears to be possible in these geometries. We will attempt to build the causality violating regions and propose that stringy effects prohibit their construction. The proposed chronology protection agent for these geometries mirrors a mechanism string theory employs to resolve a class of naked singularities. (author)

UK PubMed Central (United Kingdom)

The widely accepted oxidative stress theory of aging postulates that aging results from accumulation of oxidative damage. Surprisingly, data from the longest-living rodent known, naked mole-rats [MRs;...Full Text Available

CERN Document Server

In Randall-Sundrum-type brane-world cosmologies, the dynamical equations on the three-brane differ from the general relativity equations by terms that carry the effects of imbedding and of the free gravitational field in the five-dimensional bulk. Instead of starting from an ansatz for the metric, we derive the covariant nonlinear dynamical equations for the gravitational and matter fields on the brane. The local energy-momentum corrections are significant only at very high energies, and in this regime we show that fluid world-lines have a non-gravitational acceleration off the brane. The imprint on the brane of the nonlocal gravitational field in the bulk is more subtle, and we provide a careful decomposition of this effect. The nonlocal energy density determines the tidal acceleration in the off-brane direction, and can oppose singularity formation via the generalized Raychaudhuri equation. Unlike the nonlocal energy density and flux, the ...

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We discuss the determination of the infrared singularities of massive one-loop 5-point functions with Mellin-Barnes (MB) representations. Massless internal lines may lead to poles in the {epsilon} expansion of the Feynman diagram, while unresolved massless final state particles give endpoint singularities of the phase space integrals. MB integrals are an elegant tool for their common treatment. An evaluation by taking residues leads to inverse binomial sums. (orig.)

British Library Electronic Table of Contents (United Kingdom)

Metalloid cluster compounds of group 14 of the general formulae EnRm with n > m (E = Si, Ge, Sn, Pb; R = ligand), where naked as well as ligand bound tetrel atoms are present, represent a novel class of cluster compounds in group 14 chemistry and can be seen as intermediates on the way to the elemental state. Therefore, interesting properties are expected for these compounds, which might complement results from nanotechnology. In this article, first results for germanium are discussed, together with novel build-up reactions on the way to novel materials based on metalloid cluster compounds. GRAPHICAL ABSTRACT[image omitted

CERN Document Server

We study the well-posedness of the initial value problem for a wide class of singular evolution equations. We prove a general well-posedness theorem under three assumptions easy to check: the first controls the singular part of the equation, the second the behavior of the nonlinearities, and the third one assumes that an energy estimate can be found for the linearized system. We allow losses of derivatives in this energy estimate and therefore construct a solution by a Nash-Moser iterative scheme. As an application to this general theorem, we prove the well-posedness of the Serre and Green-Naghdi equation and discuss the problem of their validity as asymptotic models for the water-waves equations.

International Nuclear Information System (INIS)

We analyze the behavior of some Bianchi type-IX, mixmaster cosmological models possessing extra dimensions. We find that, unlike the three-dimensional case, they do not exhibit chaotic behavior on approach to their initial singularity. A finite sequence of stochastic mixmaster oscillations is, in general, replaced by monotonic contraction of the three-space scale factors on approach to a singularity whenever additional spatial dimensions exist with the metric form we consider.

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 ...

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We study systems of multiple localized closed string tachyons and the phenomena associated with their condensation, in C{sup 3}/Z{sub N} non-supersymmetric noncompact orbifold singularities using gauged linear sigma model constructions, following hep-th/0406039. Our study reveals close connections between the combinatorics of non-supersymmetric flip transitions (between topologically distinct resolutions of the original singularity), the physics of tachyons of different degrees of relevance and the singularity structure of the corresponding residual endpoint geometries. This in turn can be used to study the stability of the phases of gauged linear sigma models and gain qualitative insight into the closed string tachyon potential. (author)

International Nuclear Information System (INIS)

It is shown that the usual proof of the second law of black hole physics breaks down if there are tachyons present in the vicinity of a black hole. Explicit cases are discussed where a tachyon of positive energy falling into the Kerr singularity actually decreases the area of the Kerr black hole. (author).

International Nuclear Information System (INIS)

We compare the existing observational data on type Ia supernovae with the evolutions of the Universe predicted by a one-parameter family of tachyon models which we have introduced recently [Phys. Rev. D 69, 123512 (2004)]. Among the set of the trajectories of the model which are compatible with the data there is a consistent subset for which the Universe ends up in a new type of soft cosmological singularity dubbed big brake. This opens up yet another scenario for the future history of the Universe besides the one predicted by the standard #LAMBDA#CDM model.

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A previously studied theory of gravitation in flat space-time is applied to homogeneous and isotropic cosmological models. There exist two different classes of models without singularities: (i) ever-expanding models, (ii) oscillating models. The first class contains models with hot big bang. For these models there exist at the beginning of the universe-in contrast to Einstein's theory-very high but finite densities of matter and radiation with a big bang of very short duration. After short time these models pass into the homogeneous and isotropic models of Einstein's theory with spatial curvature equal to zero and cosmological constant ALPHA >= O.

CERN Document Server

We present a method for the analysis of singularities of Feynman amplitudes based on the Speer sector decomposition of the Schwinger parametric integrals combined with the Mellin-Barnes transform. The sector decomposition method is described in some details. We suggest the idea of applying the method to the analysis of collinear singularities in inclusive QCD cross sections in the mass-less limit regularizing the forward amplitudes by an off-shell choice of the initial particle momenta. It is shown how the suggested strategy works in the well known case of the one loop corrections to Deep Inelastic Scattering.

CERN Document Server

The X-ray spectra of some magnetized isolated neutron stars (NSs) show absorption features with equivalent widths (EWs) of 50 - 200 eV, whose nature is not yet well known. To explain the prominent absorption features in the soft X-ray spectra of the highly magnetized (B ~ 10^{14} G) X-ray dim isolated NSs (XDINSs), we theoretically investigate different NS local surface models, including naked condensed iron surfaces and partially ionized hydrogen model atmospheres, with semi-infinite and thin atmospheres above the condensed surface. We also developed a code for computing light curves and integral emergent spectra of magnetized neutron stars with various temperature and magnetic field distributions over the NS surface. We compare the general properties of the computed and observed light curves and integral spectra for XDINS RBS\\,1223 and conclude that the observations can be explained by a thin hydrogen atmosphere above the condensed iron surface, while the ...

International Nuclear Information System (INIS)

To systematically analyze the dynamical implications of the matter content in cosmology, we generalize earlier dynamical systems approaches so that perfect fluids with a general barotropic equation of state can be treated. We focus on locally rotationally symmetric Bianchi type IX and Kantowski-Sachs orthogonal perfect fluid models, since such models exhibit a particularly rich dynamical structure and also illustrate typical features of more general cases. For these models, we recast Einstein's field equations into a regular system on a compact state space, which is the basis for our analysis. We prove that models expand from a singularity and recollapse to a singularity when the perfect fluid satisfies the strong energy condition. When the matter source admits Einstein's static model, we present a comprehensive dynamical description, which includes the qualitative asymptotic behavior, of models in the neighborhood of the Einstein model; the ...

CERN Document Server

We show that the moduli space of all Calabi-Yau manifolds that can be realized as hypersurfaces described by a transverse polynomial in a four dimensional weighted projective space, is connected. This is achieved by exploiting techniques of toric geometry and the construction of Batyrev that relate Calabi-Yau manifolds to reflexive polyhedra. Taken together with the previously known fact that the moduli space of all CICY's is connected, and is moreover connected to the moduli space of the present class of Calabi-Yau manifolds (since the quintic threefold P_4[5] is both CICY and a hypersurface in a weighted P_4), this strongly suggests that the moduli space of all simply connected Calabi-yau manifolds is connected. It is of interest that singular Calabi-Yau manifolds corresponding to the points in which the moduli spaces meet are often, for the present class, more singular than the conifolds that connect the moduli spaces of CICY's.

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The standard Friedmann-Robertson-Walker (FRW) big bang model of the universe requires special initial conditions: the early universe is highly homogeneous and isotropic even though there exist causally disconnected regions (horizon problem). A plane symmetric (anisotropic) solution of field equations in a generalized theory of gravitation predicts the beginning of the universe as a vacuum instability at a specific fundamental time (which can be associated with the Planck time (tsub(p))), after which matter is created as the universe begins to expand. At a time t=tsub(c) there is a singular expansion, the anisotropy vanishes, and the physical horizon becomes infinite. Thereafter the solution of the field equations goes over into the FRW model. Thus the special initial conditions of the FRW model at the big bang singularity t=tsub(c) are predicted by the theory.

CERN Document Server

We discuss the Sundman-Weierstrass theorem of total collapse in its historical context. This remarkable and relatively simple result, a type of stability criterion, is at the crossroads of some interesting developments in the gravitation Newtonian N-body problem. We use it as motivation to explore the connections to such important concepts as integrability, singularities and tyipicality in order to gain some insight on the transition from a predominantly quantitative to a novel qualitative approach to dynamical problems that took place at the end of the 19th century.

CERN Document Server

A general theorem on the GBDT version of the B\\"acklund-Darboux transformation for systems rationally depending on the spectral parameter is treated and its applications to nonlinear equations are given. Explicit solutions of direct and inverse problems for Dirac-type systems, including systems with singularities, and for the system auxiliary to the $N$-wave equation are reviewed. New results on explicit construction of the wave functions for radial Dirac equation are obtained.

International Nuclear Information System (INIS)

Investigated are the characteristics of high-temperature plastic deformation the velocity sensitivity of flow stresses, deformation curves, flow stresses, deformation before rupture - as well as the structure of beryllium alloys containing nickel (0.5-4 %), yttrium (0.5-2 %) and aluminium (38 %). The alloys containing nickel (2%) and yttrium (0.5 %) are superplastic, however, deformation before fracture of the alloys is lower than that of the unalloyed beryllium. The singularities of high-temperature plastic flow of the alloys and the causes of deterioration of their plasticity are determined.

Energy Technology Data Exchange (ETDEWEB)

We show that the chaotic dynamical behaviour displayed by diagonal Bianchi type IX metrics in general relativity does not occur on approach to the singularity in higher-order lagrangian theories of gravity. However, chaotic behaviour does occur in the more general non-diagonal type IX models in these theories. An interpretation of these results in terms of the hamiltonian potential picture of the type IX evolution is given. (orig.).

Energy Technology Data Exchange (ETDEWEB)

We present a set of exact solutions for quantum Bianchi type-IX anisotropic cosmological models (including the Taub model) of the form {Psi}={ital We}{sup {minus}{ital S}}. These solutions are spread over all values of anisotropy near the singularity, but at larger values of the radius of the universe they are strongly peaked around the {ital k}=+1 Friedmann-Robertson-Walker model.

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Numerical simulations of compressible flows are commonly based on the Euler equations when effects of viscosity are thought to be negligible. These equations admit singular solutions, even in cases where the initial and boundary conditions are smooth. So-called ''Euler solvers'' rely on numerical dissipation, explicitly or implicitly present in the scheme, to regularize the problem, such that physical solutions are selected.

International Nuclear Information System (INIS)

The dynamics of a general Bianchi type-IX model with three scale factors is examined. The matter content of the model is assumed to be comoving dust plus a positive cosmological constant. The model presents a critical point of saddle-center-center type in the finite region of phase space. This critical point engenders in the phase space dynamics the topology of stable and unstable four dimensional tubes RxS"3, where R is a saddle direction and S"3 is the manifold of unstable periodic orbits in the center-center sector. A general characteristic of the dynamical flow is an oscillatory mode about orbits of an invariant plane of the dynamics which contains the critical point and a Friedmann-Robertson-Walker (FRW) singularity. We show that a pair of tubes (one stable, one unstable) emerging from the neighborhood of the critical point towards the FRW singularity have homoclinic transversal crossings. The homoclinic intersection manifold has topology ...

CERN Document Server

We calculate quark-antiquark potentials using the relationship between the expectation value of the Wilson loop and the action of a probe string in the string dual. We review and categorize the possible forms of the dependence of the energy on the separation between the quarks. In particular, we examine the possibility of there being a minimum separation for probe strings which do not penetrate close to the origin of the bulk space, and derive a condition which determines whether this is the case. We then apply these considerations to the flavoured resolved deformed conifold background of Gaillard et al. We suggest that the unusual behaviour we observe in this solution is likely to be related to the IR singularity which is not present in the unflavoured case.

British Library Electronic Table of Contents (United Kingdom)

We have explored vibrations of a single-degree of freedom oscillator with a magneto-rheological damper subjected to kinematic excitations in a high frequency limit. Using fast and slow scales decoupling procedure we derived an effective damping coefficient in the limit of high frequency excitation. Damping characteristics, as functions of velocity, change considerably especially by terminating the singular non-smoothness points. This effect was more transparent for a larger control parameter which was defined as the product of the excitation amplitude and its frequency.

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Bhabha scattering is one of the processes at the ILC where high precision data will be expected. The complete NNLO corrections include radiative loop corrections, with contributions from Feynman diagrams with five external legs. We take these diagrams as an example and discuss several features of the evaluation of pentagon diagrams. The tensor functions are usually reduced to simpler scalar functions. Here we study, as an alternative, the application of Mellin-Barnes representations to 5-point functions. There is no evidence for an improved numerical evaluation of their finite, physical parts. However, the approach gives interesting insights into the treatment of the IR- singularities. (orig.)

International Nuclear Information System (INIS)

Each choice of an arbitrary nonzero function f of the four immersion parameters is shown to determine 16N[f] distinguishable classes of two-parameter families of immersions of Einstein-Riemann spacetimes in six-dimensional flat spaces, where N[f] is the number of regular immersion parameter domains. The metric tensors, curvature tensors and the immersion loci are calculated in a closed form, and these calculations involve only finitely many algebraic operations. The presence of the arbitrary function provides the opportunity for study of the behaviour of multiple isolated singularities and/or 'shape' functions in general relativity.

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An outline of the multi-fault diagnostic observation concept is presented in the paper. Starting from the commonly used singular value decomposition (SVD) it is shown, that it is equivalent to the modern version of principal component analysis (PCA). During the development of the concept of multi-fault observation several indices and measures obtained from SVD were tried, and some seem to bring the success. This problem is also addressed in the paper and illustrated by real examples taken from railroad Diesel engine condition monitoring. (orig.)

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It is shown that all contracting, spatially homogeneous, orthogonal Bianchi cosmologies that are sourced by an ultra-stiff fluid with an arbitrary and, in general, varying equation of state asymptote to the spatially flat and isotropic universe in the neighbourhood of the big crunch singularity. This result is employed to investigate the asymptotic dynamics of a collapsing Bianchi type IX universe sourced by a scalar field rolling down a steep, negative exponential potential. A toroidally compactified version of M*-theory that leads to such a potential is discussed and it is shown that the isotropic attractor solution for a collapsing Bianchi type IX universe is supersymmetric when interpreted in an 11-dimensional context.

International Nuclear Information System (INIS)

We consider the dynamics toward the initial singularity of Bianchi type IX vacuum and orthogonal perfect fluid models with a linear equation of state. The 'Bianchi type IX attractor theorem' states that the past asymptotic behavior of generic type IX solutions is governed by Bianchi type I and II vacuum states (Mixmaster attractor). We give a comparatively short and self-contained new proof of this theorem. The proof we give is interesting in itself, but more importantly it illustrates and emphasizes that type IX is special, and to some extent misleading when one considers the broader context of generic models without symmetries.

CERN Document Server

The Belinskii, Khalatnikov and Lifshitz conjecture \\cite{bkl1} posits that on approach to a space-like singularity in general relativity the dynamics are well approximated by `ignoring spatial derivatives in favor of time derivatives.' In \\cite{ahs1} we examined this idea from within a Hamiltonian framework and provided a new formulation of the conjecture in terms of variables well suited to loop quantum gravity. We now present the details of the analytical part of that investigation. While our motivation came from quantum considerations, thanks to some of its new features, our formulation should be useful also for future analytical and numerical investigations within general relativity.

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There are 760 feederpipes, which they are connected to inlet/outlet of the 380 pressure tube channels on the front of the calandria, in CANDU-type Reactor of Wolsung Nuclear Power Plant. As an ISI(In-Service Inspection) and PSI (Post- Service Inspection) requirements, maintenance activities of measuring the thickness of curvilinear part of feederpipe and inspecting the feederpipe support area within calandria are needed to ensure continued reliable operation of nuclear power plant. And untrasonic probe is used to measure the thickness of curvilinear part of feederpipe, however workers are exposed to radioactivity irradiation during the measurement period. But, it is impossible to inspect feederpipe support area thoroughlv because of narrow and confined accessibility, that is, an inspection space between the pressure tube channels is less than 100mm and pipes in feederpipe support area are congested. And also, workers involved in inspecting feederpipe support area are under the jeopardy ...

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Predictions of the combination of our recent model for the formation of planetary nebulae (due to a diverging pulsational instability) together with nuclear-burning shell flashing, with regard to formation of multiple shells, are explored and discussed.

Energy Technology Data Exchange (ETDEWEB)

Short communication

Science.gov (United States)

Methods of acidizing a subterranean well formation, acidizing compositions, and sequestering additives for preventing the precipitation of metal compounds in the formation are described. Use of the methods and chemicals described should lead to improved formation permeability as compared to use of previous methods and chemicals. 12 claims.

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At moderately low momentum transfer ($-t$ up to 1 GeV$^2$) the coupling to the vector meson production channels gives the dominant contribution to real Compton and deeply virtual Compton scattering (DVCS). Starting from a Regge Pole approach that successfully describes vector meson production, the singular part of the corresponding box diagrams (where the intermediate vector meson-baryon pair propagates on-shell) is evaluated without any further assumptions (unitarity). Such a treatment explains not only the unexpectedly large DVCS unpolarized cross section that has been recently measured at Jefferson Laboratory (JLab), but also all the beam spin and charge asymmetries that has been measured at JLab and Hermes, without explicit need of Generalized Parton Distributions (GPD). The issue of the relationship between the two approaches is addressed.

CERN Document Server

Hidden Markov models (HMMs) are probabilistic functions of finite Markov chains, or, put in other words, state space models with finite state space. In this paper we examine subspace estimation methods for HMMs whose output lies a finite set as well. In particular we study the geometric structure arising from the non-minimality of the linear state space representation of HMMs, and consistency of a subspace algorithm arising from a certain factorisation of the singular value decomposition of the estimated linear prediction matrix. For this algorithm we show that the estimates of the transition and emission probability matrices are consistent up to a similarity transformation, and that the m-step linear predictor computed from the estimated system matrices is consistent, i.e. converges to the true optimal linear m-step predictor.

CERN Document Server

The full theory and the semiclassical description of loop quantum cosmology (LQC) have been studied in the Friedmann-Robertson-Walker and Bianchi I models. As an extension to include both anisotropy and intrinsic curvature, this paper investigates the cosmological model of Kantowski-Sachs spacetime with a free massless scalar field at the level of phenomenological dynamics with the LQC discreteness corrections. The LQC corrections are implemented in two different improved quantization schemes. In both schemes, the big bang and big crunch singularities of the classical solution are resolved and replaced by the big bounces when the area or volume scale factor approaches the critical values in the Planck regime measured by the reference of the scalar field momentum. Symmetries of scaling are also noted and suggest that the fundamental spatial scale (area gap) may give rise to a temporal scale. The bouncing scenarios are in an analogous fashion of the Bianchi I model, ...

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.

Energy Technology Data Exchange (ETDEWEB)

We consider the dynamics towards the initial singularity of Bianchi type IX vacuum and orthogonal perfect fluid models with a linear equation of state. Surprisingly few facts are known about the 'Mixmaster' dynamics of these models, while at the same time most of the commonly held beliefs are rather vague. In this paper, we use Mixmaster facts as a base to build an infrastructure that makes it possible to sharpen the main Mixmaster beliefs. We formulate explicit conjectures concerning (i) the past asymptotic states of type IX solutions and (ii) the relevance of the Mixmaster/Kasner map for generic past asymptotic dynamics. The evidence for the conjectures is based on a study of the stochastic properties of this map in conjunction with dynamical systems techniques. We use a dynamical systems formulation, since this approach has so far been the only successful path to obtain theorems, but we also make comparisons with the 'metric' ...

International Nuclear Information System (INIS)

We describe in detail the space of the two Kaehler parameters of the Calabi-Yau manifold P_4"("1","1","1","6","9")[D. R. Morrison, 1993] by exploiting mirror symmetry. The large complex structure limit of the mirror, which corresponds to the classical large radius limit, is found by studying the monodromy of the periods about the discriminant locus, the boundary of the moduli space corresponding to singular Calabi-Yau manifolds. A symplectic basis of periods is found and the action of the Sp(6, Z) generators of the modular group is determined. From the mirror map we compute the instanton expansion of the Yukawa couplings and the generalized N=2 index, arriving at the numbers of instantons of genus zero and genus one of each bidegree. We find that these numbers can be negative, even in genus zero. We also investigate an SL(2, Z) symmetry that acts on a boundary of the moduli space. ((orig.)).

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Lie group methods provide a valuable tool for examininginvariance and non-uniqueness associated with geophysical inverseproblems. The techniques are particularly well suited for the study ofnon-linear inverse problems. Using the infinitesimal generators of thegroup it is possible to move within the null space in an iterativefashion. The key computational step in determining the symmetry groupsassociated with an inverse problem is the singular value decomposition(SVD) of a sparse matrix. I apply the methodology to the eikonal equationand examine the possible solutions associated with a crosswelltomographic experiment. Results from a synthetic test indicate that it ispossible to vary the velocity model significantly and still fit thereference arrival times. the approach is also applied to data fromcorosswell surveys conducted before and after a CO2 injection at the LostHills field in California. The results highlight the fact that a faultcross-cutting the region ...

CERN Document Server

We consider typeIIA supergravity solution of D2-branes and D3-branes localized within D6-branes in the near-core region of D6-branes. With these solutions we can calculate the spectrum of the glueball mass in QCD3 and QCD4. The equation of motion describing the dilaton has the same eigenvalues and the same glueball masses in QCD3 and QCD4. Glueball mass spectrum is the same in the near core region of D6-branes of their M-theory counterpart is KK monopole. We conclude that the glueball mass spectrum is the same in QCD3 and QCD4 by considering the `near-core' limit of D6-branes of which M-theory counterpart (KK monopole background) becomes an ALE space with an $A_{N-1}$ singularity times 7 dimensional Minkowski space $M^{(6,1)}$.

CERN Document Server

A new mathematical framework is formulated to derive the effective equations of motion for the constrained quantum system which possesses an internal clock. In the realm close to classical behavior, the quantum evolution is approximated by a finite system of coupled but ordinary differential equations adhered to the weakly imposed Hamiltonian constraint. For the simplified version of loop quantum cosmology in the Bianchi I model with a free massless scalar filed, the resulting effective equations of motion affirm the bouncing scenario predicted by the previous studies: The big bang singularity is resolved and replaced by the big bounces, which take place up to three times, once in each diagonal direction, whenever the directional density approaches the critical value in the regime of Planckian density. It is also revealed that back-reaction arises from the quantum corrections and modifies the precise value of the directional density at the bouncing epoch. ...

Energy Technology Data Exchange (ETDEWEB)

The dynamical effects of spatially homogeneous electromagnetic fields on anisotropic Bianchi type-IX models are studied. The Lagrangians and Hamiltonians affecting the evolution of anisotropy (including the gravitational and electromagnetic potentials) are obtained for very general spatially homogeneous metrics by means of the Arnowitt-Deser-Misner Hamiltonian formalism. For models having diagonal metrics an exact solution for the electromagnetic fields is obtained. This solution allows a qualitative solution for the gravitational variables. The total solution is similar to that of Brill. For Bianchi type-IX models having symmetric and general metrics, a discussion of the qualitative behavior of the universe point under the influence of the above potentials is given. In particular, it is shown that in some cases the presence of the electromagnetic potential inhibits some types of singularities.

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 scalar field is effectively massless, and the solution is ...

Energy Technology Data Exchange (ETDEWEB)

We investigate the dynamics of an 11-dimensional homogeneous cosmological model. We assume that the t = const hypersurfaces are products of a 3-dimensional Bianchi type-IX space and a 7-dimensional torus. Most results of our investigation hold when the 7-dimensional torus is replaced by an m-dimensional torus T/sup m/. We show that for a large class of vacuum solutions the physical space expands while the microspace contracts providing a natural mechanism of dimensional reduction. Matter satisfying a simple barotropic equation of state always breaks the process of dynamical dimensional reduction. With special attention we study the behavior of our model close to the initial singularity. In contrast with the 4-dimensional Bianchi type-IX cosmological model the Kasner solution always describes an approach to the initial singularity. We study the transition from the Kasner regime to the oscillatory regime. We show that matter does not ...

British Library Electronic Table of Contents (United Kingdom)

An approach to the calculation of the quantity of heat consumed in the process of coal formation is presented. The variability of this parameter in a coalification series is analyzed using coals from the Kuznetsk and Tunguska Basins as an example.

UK PubMed Central (United Kingdom)

The formation of the nicotinamide adenine dinucleotide phosphate-dependent formate dehydrogenase in Clostridium thermoaceticum is stimulated by the presence of molybdate and selenite...Full Text Available

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International Patenting Trends in Advanced Materials: Ceramics (June 18, 1999) This report is the ... manufacturing, biotechnology, and advanced materials. Hypertext Format Portable Document Format ...

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Neutrino processes role in star evolution and onset of supernovae explosion

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International Nuclear Information System (INIS)

Cyclic strength of #alpha#+#beta#-titanium alloy BT3-1 is studied under load frequencies of 33 and 300 Hz. The increase in the cyclic strength with growing frequency is caused by formation of FCC interphase layers of titanium hydrides. Their formation is one of possible ways of raising the fatigue strength of titanium alloys. Peculiarities of FCC interlayer formation in #alpha#+#beta# phases under loading frequency variation are revealed.

International Nuclear Information System (INIS)

... 1343-3563 v. 57(1) SPECIFIC NUCLEAR REACTORS AND ASSOCIATED

International Nuclear Information System (INIS)

Published in summary form only.

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Chlorination of water can lead to the formation of chloropicrin. The numerous potential precursors (of various reactivities) observed during this study, confirm this hypothesis. Combination of ozonation and chlorination can also lead to the formation of this compound, dangerous to health; however, the conditions of the formation and particularly the impact of a nitration reaction in the gas phase are still not clearly defined.

Science.gov (United States)

ice could be responsible for the formation of martian gullies. Tomorrow's picture: whirlpool ...

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The Coalspur Formation is a continental succession of interbedded mudstone, siltstone and fine grained sandstone with subordinate coarser grained sandstone layers and channel lag deposits. Chert-pebble conglomerate (the Entrance conglomerate) occurs at the base of the formation, and coal beds interbedded with coaly shale and numerous thin bentonites occur in the upper part of the formation. An economically significant amount of high-quality thermal coal occurs within the upper, Paleocene part of the formation named the Coalspur coal zone. Coal from this zone, also known as the Coal Valley coal zone is being exploited in the Coal Valley Mine. 17 refs., 4 figs.

CERN Document Server

We show that the renormalization group decimation of modern nucleon potential models to low momenta results in a unique nucleon interaction V_{low k}. This interaction is free of short-ranged singularities and can be used directly in many-body calculations. The RG scaling properties follow directly from the invariance of the scattering phase shifts. We discuss the RG treatment of Fermi liquids. The RG equation for the scattering amplitude in the two particle-hole channels is given at zero temperature. The flow equations are simplified by retaining only the leading term in an expansion in small momentum transfers. The RG flow is illustrated by first studying a system of spin-polarized fermions in a simple model. Finally, results for neutron matter are presented by employing the unique low momentum interaction V_{low k} as initial condition of the flow. The RG approach yields the amplitude for non-forward scattering, which is of great interest for calculations of ...

International Nuclear Information System (INIS)

We consider spatially homogeneous (but generally non-isotropic) cosmologies in the recently proposed Horava-Lifshitz gravity and compare them to those of general relativity using Hamiltonian methods. In all cases, the problem is described by an effective point particle moving in a potential well with exponentially steep walls. Focusing on the closed-space cosmological model (Bianchi type IX), the mixmaster dynamics is now completely dominated by the quadratic Cotton tensor potential term for a very small volume of the universe. Unlike general relativity, where the evolution toward the initial singularity always exhibits chaotic behavior with alternating Kasner epochs, the anisotropic universe in Horava-Lifshitz gravity (with parameter #lambda# > 1/3) is described by a particle moving in a frozen potential well with fixed (but arbitrary) energy E. Alternating Kasner epochs still provide a good description of the early universe for very large E, but the evolution ...

CERN Document Server

We study the evolution of an isolated, spherical halo of self-interacting dark matter (SIDM) in the gravothermal fluid formalism. We show that the thermal relaxation time, $t_r$, of a SIDM halo with a central density and velocity dispersion of a typical dwarf galaxy is significantly shorter than its age. We find a self-similar solution for the evolution of a SIDM halo in the limit where the mean free path between collisions, $\\lambda$, is everywhere longer than the gravitational scale height, $H$. Typical halos formed in this long mean free path regime relax to a quasistationary gravothermal density profile characterized by a nearly homogeneous core and a power-law halo where $\\rho \\propto r^{-2.19}$. We solve the more general time-dependent problem and show that the contracting core evolves to sufficiently high density that $\\lambda$ inevitably becomes smaller than $H$ in the innermost region. The core undergoes secular collapse to a singular state (the ...

International Nuclear Information System (INIS)

Isomers have been populated in "2"4"6Cm and "2"5"2No with quantum numbers K"#pi#=8"-, which decay through K"#pi#=2"- rotational bands built on octupole vibrational states. For N=150 isotones with (even) atomic number Z=94-102, the K"#pi#=8"- and 2"- states have remarkably stable energies, indicating neutron excitations. An exception is a singular minimum in the 2"- energy at Z=98, due to the additional role of proton configurations. The nearly constant energies, in isotones spanning an 18% increase in Coulomb energy near the Coulomb limit, provide a test for theory. The two-quasiparticle K"#pi#=8"- energies are described with single-particle energies given by the Woods-Saxon potential and the K"#pi#=2"- vibrational energies by quasiparticle random-phase approximation calculations. Ramifications for self-consistent mean-field theory are discussed.

International Nuclear Information System (INIS)

The O(#alpha#) electroweak radiative corrections to #gamma##gamma##->#WW#->#4f within the electroweak standard model are calculated in double-pole approximation (DPA). Virtual corrections are treated in DPA, leading to a classification into factorizable and non-factorizable contributions, and real-photonic corrections are based on complete lowest-order matrix elements for #gamma##gamma##->#4f+#gamma#. Soft and collinear singularities appearing in the virtual and real corrections are combined alternatively in two different ways, namely by using the dipole subtraction method or by applying phase-space slicing. The radiative corrections are implemented in a Monte Carlo generator called Coffer #gamma##gamma# - the computer code can be obtained from the authors upon request - which optionally includes anomalous triple and quartic gauge-boson couplings in addition and performs a convolution over realistic spectra of the photon beams. A detailed survey of ...

International Nuclear Information System (INIS)

A spectrophotometric study has been made of the complex formation of vanadium (3) with arsenazo(1), arsenazo(3) and some monosubstituted derivatives of chromotropic acid and sulphanylamides. In acid medium vanadium (3) reacts with each of these reagents to produce a 1:1 complex. Optimum conditions of the complex formation was found. The effect of H"+ on the complex formation of vanadium (3) with chromotropic acid derivatives was established. It was found by the graphical method that the formation of the complex is accompanied by the elimination of one proton. Patterns were found of the influence of the nature of substituents in the organic compound on the ionization constants of acid groups and stability of complexes. Molar extinction coefficients, equilibrium constants of the formation reactions and instability constants for the complexes were calculated. The structure of complexes ...

UK PubMed Central (United Kingdom)

Peri-prosthetic infections are notoriously difficult to treat as the biomaterial implant is ideal for bacterial adhesion and biofilm formation, resulting in decreased antibiotic sensitivity....Full Text Available

UK PubMed Central (United Kingdom)

In an earlier report, we used differential cloning to identify genes that might be critical in controlling arterial neointima formation (Giachelli, C., N. Bae, D. Lombardi, M. Majesky, and S. Schwartz....Full Text Available

Energy Technology Data Exchange (ETDEWEB)

The present invention relates to a method of acidizing a subterranean formation or well bore employing an acidic solution containing a corrosion inhibitor composition comprising an inhibiting effective amount of an acetylenic alcohol, a quaternary ammonium compound, an aromatic hydrocarbon and an antimony compound.

UK PubMed Central (United Kingdom)

External application of auxin and cytokinin is required for the formation of flower buds on thin-layer tissue explants of Nicotiana tabacum cv Samsun. Interaction between both plant...Full Text Available

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An analysis is made of the manner in which the process of primordial black-hole formation and the subsequent accretion of gas depend on the equation of state. On the assumption that the process is spherically symmetric, the problem is solved numerically.

UK PubMed Central (United Kingdom)

Explants from flower stalks of Nicotiana tabacum L. were cultured on different cytokinins to induce flower bud formation. All cytokinins tested except zeatin and zeatin-riboside induced...Full Text Available

International Nuclear Information System (INIS)

... thermal power plants thermal reactors water cooled reactors WATER

Science.gov (United States)

... This pinhole process may be similar to the formation of an oxide layer in aluminum electrolytic capacitors immersed in a borax solution. ...

KoreaScience (Korea)

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International Nuclear Information System (INIS)

We have investigated the formation and coarsening of Ga droplets on focused-ion-beam (FIB) irradiated GaAs surfaces. To separately examine formation and coarsening, Ga droplets were fabricated by Ga"+ FIB irradiation of GaAs substrates with and without pre-patterned holes. We determined the droplet growth rate and size distribution as a function of FIB energy following irradiation. The data suggest a droplet formation mechanism that involves Ga precipitation from a Ga-rich layer, followed by droplet coarsening via a combination of diffusion and Ostwald ripening or coalescence via droplet migration (dynamic coalescence).

International Nuclear Information System (INIS)

Formation of basis type texture at rolling of Ti + 6.0% Al + 1.5% V + 1.0% Mo system alloy with initial prismatic texture is investigated by means of X-ray techniques. Variations of mechanical features in titanium alloy sheets depending on temperature-deformation conditions of rolling are investigated. Main conditions for formation of the intensive basis textute in the investigated alloy sheets which provides for isotropic properties in sheet plane and for increased ductility are determined.

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This book of proceedings reports on 7 papers on combustion chemistry and formation of pollutants presented during the workshop organized by the `Combustion and Flames` section of the French society of thermal engineers. The chemistry of combustion is analyzed in various situations such as: turbojet engines, spark ignition engines, industrial burners, gas turbines etc... Numerical simulation is used to understand the physico-chemical processes involved in combustion, to describe the kinetics of oxidation, combustion and flame propagation, and to predict the formation of pollutants. (J.S.)

International Nuclear Information System (INIS)

The analysis of plasma density oscillations and ExB rotation of U-3M torsatron plasma was performed by UHR correlation reflectometry during the transport barrier formation. The connections between these characteristics and the phenomenon of inner and edge transport barrier formation were determined experimentally at the different values of HF power and plasma density.

Science.gov (United States)

The Multiple Address Processing Unit (MAPU) of the AN/TGC-26 tape relay center was originally designed to process ACP 127 message format. With the advent of JANAP 128 as a standardized message format a pressing need was felt for a MAPU modification to all...

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The results of a time-resolved study of the avalanche and streamer formation phases leading to breakdown in atmospheric nitrogen and dry air. Results of experiments and two-dimensional simulations are presented. It is shown what processes are responsible for the formation of a streamer. The trends of externally measured quantities correspond with those predicted by our model. 3 figs., 5 refs.

Science.gov (United States)

(B204) The meeting will bring together observers and theorists in a highly interactive format, to further connect the local and cosmological star formation communities. Forward looking talks, aimed at the other communities, will survey terminology, achievements, problems and aspirations. Discussion will focus on the definition of the key questions, how the different communities can help each other, and preparations for the incorporation of realistic star formation into cosmological simulations.

International Nuclear Information System (INIS)

The results of real-time neutron diffraction measurements during the superconducting phase formation process in the Bi(Pb)-Sr-Ca-Cu-O system are reported. A Sr-Ca-Cu-O type precursor, with the same stoichiometry as the 2223 phase, was used as starting material, and the temperature range favorable to the formation of the 2223 phase was investigated. The diffraction patterns were processed by a multiphase Rietveld refinement. The formation and decomposition of the 2201 and 2212 phases were directly observed. Experimental evidence on the existence of a partially melted phase in the range 855-860 degrees C, involved in the formation of the 2223 phase, is discussed. 14 refs., 9 figs., 1 tab.

International Nuclear Information System (INIS)

The redistribution of implanted As and Sb following metal-silicide formation of Pt, Pd, and Ni has been studied. The phases of the silicides used were PtSi, Pd_2Si, and NiSi. Investigations with Rutherford backscattering analysis showed that after the formation of the silicides, the Sb was always found in the silicide layer near the surface of the samples, whereas PtSi and Pd_2Si caused a partial rejection of As for implanted doses of 2 x 10"1"5 cm"-"2 and higher. No rejection of As was found after the formation of NiSi. The results are discussed in terms of solid solubilities and impurity-metal compound formation. The data presented has implications in the fabrication of Ohmic contacts and the adjustments of the heights of Schottky barriers on silicon.

British Library Electronic Table of Contents (United Kingdom)

Summary: The KEGG PATHWAY database provides a widely used service for metabolic and nonmetabolic pathways. It contains manually drawn pathway maps with information about the genes, reactions and relations contained therein. To store these pathways, KEGG uses KGML, a proprietary XML-format. Parsers and translators are needed to process the pathway maps for usage in other applications and algorithms. We have developed KEGGtranslator, an easy-to-use stand-alone application that can visualize and convert KGML formatted XML-files into multiple output formats. Unlike other translators, KEGGtranslator supports a plethora of output formats, is able to augment the information in translated documents (e.g. MIRIAM annotations) beyond the scope of the KGML document, and amends missing components to fr...

CERN Document Server

Several complex organic molecules are routinely detected in high abundances towards hot cores and hot corinos. For many of them, their paths of formation in space are uncertain, as gas phase reactions alone seem to be insufficient. In this paper, we investigate a possible solid-phase route of formation for methyl formate (HCOOCH3). We use a chemical model updated with recent results from an experiment where simulated grain surfaces were irradiated with 200 keV protons at 16 K, to simulate the effects of cosmic ray irradiation on grain surfaces. We find that this model may be sufficient to reproduce the observed methyl formate in dark clouds, but not that found in hot cores and corinos.

International Nuclear Information System (INIS)

Applying the theory of depositional system, the depositional facies and depositional systems of the Zhiluo Formation in Dongsheng area are systematically analysed, and the authors proposed that sediments of the Zhiluo Formation are of fluvial facies, and streams of the Zhiluo time experienced three evolution stages, namely: the early braided stream, the middle low sinuosity meandering stream and the late high sinuosity meandering stream. Based on features of paleoclimatic evolution, the Zhiluo Formation is divided into two lithological members. The lower lithological member consists of sediments of braided and low sinuosity meandering streams under humid-ward paleoclimatic conditions forming grey sedimentary formation. The upper member is composed of sediments of meandering streams under arid-hot paleoclimatic conditions representing complex-colored (mainly red) sedimentary ...

Science.gov (United States)

Outbreaks of disease attributable to human error or natural causes can provide unique opportunities to gain new information about host-pathogen interactions and new leads for pathogenesis research. Poststreptococcal glomerulonephritis (PSGN), a sequela of infection with pathogenic streptococci, is a common cause of preventable kidney disease worldwide. Although PSGN usually occurs after infection with group A streptococci, organisms of Lancefield group C and G also can be responsible. Despite decades of study, the molecular pathogenesis of PSGN is poorly understood. As a first step toward gaining new information about PSGN pathogenesis, we sequenced the genome of Streptococcus equi subsp. zooepidemicus strain MGCS10565, a group C organism that caused a very large and unusually severe epidemic of nephritis in Brazil. The genome is a circular chromosome of 2,024,171 bp. The genome shares extensive gene content, including many virulence factors, with genetically related group A ...

International Nuclear Information System (INIS)

Four very common long term mineralogical changes in salt formations are discussed in the view of the safety considerations for underground repositories. Two of these processes, the 'Hartsalz' and 'Carnallite' dissolution were studied in two scale in situ experiments. The results are presented and compared with the results of the geochemical modelling with the computer code EQ3/6. Furthermore the reactions leading to the formation of the gypsum cap rock on the top of the Zechstein salt formations and to the polyhalitization of anhydrite are discussed. Geological field observations and mineral assemblages agree well with the results of the geochemical modelling employing the Pitzer formalism along with the Harvie, Moller and Weare database. We conclude that once the mechanisms of the chemical reactions are well understood it becomes possible to evaluate realistically whether such processes, when encountered in the repository, ...

International Nuclear Information System (INIS)

The ore-hosting Yaojia Formation is composed of a set of braided stream medium-fine grained sediments. Guided by the basic theory of high-resolution sequence stratigraphy, and based on the core observation, the analysis of chemical composition of rocks, and data of natural potential logging and apparent resistivity logging, the authors have set up the high-resolution sequence stratigraphy framework of the ore-hosting Yaojia Formation, and discussed the relation of the stratigraphic structure of the middle cycle, as well as the paleotopography, the micro-facies to the formation of uranium deposit. (authors)

Energy Technology Data Exchange (ETDEWEB)

Depth resolved positron annihilation studies on Pd/Si thin film system have been carried out to investigate silicide phase formation and vacancy defect production induced by thermal annealing. The evolution of defect sensitive S-parameter clearly indicates the presence of divacancy defects across the interface, due to enhanced Si diffusion beyond 870 K consequent to silicide formation. Corroborative glancing incidence X-ray diffraction (GIXRD), Auger electron spectroscopy (AES) and Rutherford backscattering spectrometry (RBS) have elucidated the aspects related to silicide phase formation and Si surface segregation.

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Nanoparticles represent versatile building blocks in material science and nanotechnology. Thereby, the defined assembly of nanostructures (13 and 56 nm in diameter, respectively) is of significant importance. Short DNA sequences can be bound to the nanoparticle surface thus enabling highly specific DNA hybridization-driven events that direct the formation of nanoparticle constructs.In this paper, examples for the defined formation of gold nanoparticle constructs are demonstrated. In addition, gold-silver core-shell nanoparticles are introduced as further building blocks for the hybridization-controlled formation of nanoparticle constructs.

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Reaction of At(I) with triphenylphosphine, triethylphosphite and tri-n-octylphosphine oxide was investigated in ethanolic solution by means of electromigration. A cationic complex with triphenylphosphine was identified being stable at pH = 1,9 in the concentration range of the ligand between c = 10{sup -5} to 10{sup -3} M. At a higher ligand concentration and at pH>2, the reduction effect of phosphine is superimposed on the complex formation. Complex formation is confirmed by ligand exchange reactions with Br{sup -} and I{sup -}. A comparatively weak complex is formed by triethylphosphite and At(I). No compound is formed by tri-n-octylphosphine oxide and At(I). (orig.).

British Library Electronic Table of Contents (United Kingdom)

Abstract We analyse extinction maps of nearby giant molecular clouds to forge a link between driving processes of turbulence and modes of star formation. Our investigation focuses on cloud structure in the column density range above the self-shielding threshold of 1-mag AV and below the star formation threshold - the regime in which turbulence is expected to dominate. We identify clouds with shallow mass distributions as cluster forming. Clouds that form stars in a less clustered or isolated mode show a steeper mass distribution. Structure functions prove inadequate to distinguish between clouds of different star formation mode. They may, however, suggest that the turbulence in the average cloud is governed by solenoidal forcing. The same is found using the -variance analysis which also in...

Science.gov (United States)

Ti-Ag and Ti-Pd-Ag solar cell contacts structure and degradation dependence on high temperature and humidity environmental exposure

KoreaScience (Korea)

Full Text Available

Science.gov (United States)

indications of the formation of palladium silicides. 2, 4. It has been reported .... At room temperature, palladium silicides formed in a relatively narrow interface ...

Environmental Research Database

ObjectivesTo determine what biodiversity data is held by record centres for the South Downs Lifescapes pilot area and the format in which it is stored.

Science.gov (United States)

The formation of palladium silicides near the interface may decrease hydrogen solubility at the effective metal/semiconductor ...

Science.gov (United States)

... kinematic model for the robots and designed ... theoretic approach for modeling mobile robot teamn formations". ... "UUV teams, control from a biological ...

UK PubMed Central (United Kingdom)

The effect of different media and pH on the formation of amylase by Aspergillus oryzae EI 212 is described. Depending upon the composition of the medium and growth...Full Text Available

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The grey-black mudstones of the Sonehat Formation form part of the Middle Jurassic fill of the Jameson Land Basin in East Greenland. The formation is exposed in the southernmost part of the north south-trending, Mesozoic rift system in East Greenland that was part of the epeiric seaway betaveen East Greenland and Norway. Sedimentological observations of the Sortehat Formation indicate deposition in an offshore marine setting that was typically low energy and periodically oxygen-deficient but was influenced by storm currents on occasion. Detailed palynological studies of the Sortehat Formation have resulted in the definition of theee palynological assemblage zones recognised at four localities, namely Enhjoerningen Dal and Pelion (north Jameson Land), the type section at Sortehat (central Jameson Land) and Albuen at Neill Klinter along Hurry Inlet (south-east Jameson Land). In stratigraphic order, these ...

UK PubMed Central (United Kingdom)

This article addresses the need for new data on indirect effects of natural and anthropogenic aerosol particles on atmospheric ice clouds. Simultaneous measurements of the concentration and composition...Full Text Available

International Nuclear Information System (INIS)

Spanish 2001 p. 10-18 Uruguay Ubilla, M. Lorenzo, N. Depto. de

UK PubMed Central (United Kingdom)

Purpose. Formation of a tracheoinnominate artery fistula (TIF) and consecutive hemorrhage is a rare and life-threatening complication with high mortality. Warning symptoms can...Full Text Available

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

Energy Technology Data Exchange (ETDEWEB)

Pd/Ag alloy hollow spheres have been synthesized in ethylene glycol solution by the solvothermal method and have been characterized extensively. TEM results have revealed the formation of Pd/Ag hollow spheres. Moreover, HRTEM results confirmed the formation of Pd/Ag alloy spheres, where the lattice fringe spacing is 0.229 nm corresponding to the (111) plane of Pd/Ag alloy. SEM, XRD and UV-vis results have further suggested the formation of alloy hollow spheres. The preliminary results showed the reaction time may be an importance factor influencing the formation of Pd/Ag alloy hollow spheres.

UK PubMed Central (United Kingdom)

The regulation of blood vessel formation is of fundamental importance to many physiological processes, and angiogenesis is a major area for novel therapeutic approaches to diseases from ischemia to...Full Text Available

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The carbonate rocks of the Lower Ordovician Majiagou Formation represent important hydrocarbon reservoirs in the Ordos basin in the western part of the North China plate. Cores and thin sections from more than 60 wells were examined. The main reservoir in the Majiagou Formation consists of fine crystalline dolomite, which was altered by meteoric water during an extended subaerial exposure. Three phreatic zones have been identified in the Majiagou Formation in the northern part of the basin. Oxygen isotopes and fluid inclusion microthermometry data indicates that the porosity developed during the early karst event was considerably reduced by the late-stage, coarse crystalline calcite cements that appear to be related to hydrothermal fluids during deep burial. It was concluded that the main factors that determine the porosity and permeability of these carbonate reservoirs are dolomitization, karstification, and calcite ...

UK PubMed Central (United Kingdom)

Purpose:To report crystal formation as a complication of intravitreal ganciclovir injection.Patients and methods:A 73-year-old female patient with...Full Text Available

International Nuclear Information System (INIS)

Published in summary form only.

Energy Technology Data Exchange (ETDEWEB)

The project is focusing on the formation and growth mechanisms of atmospheric aerosol and cloud droplets. Both aerosol particles and cloud droplets affect strongly on the atmospheric radiation fluxes by scattering and absorption. The droplet formation results from physical and chemical processes occurring simultaneously. The studies concerning the tropospheric cloud droplet formation, laboratory experiments with a cloud chamber and stratospheric cloud formation are summarized. The recent studies summarized in this presentation indicate that both aerosol particles and cloud droplets have a significant role in climatic change and ozone depletion problems. The anthropogenic emissions of gaseous and particulate pollutants change the properties of atmospheric aerosols and cloud droplets. The research in this field will be continued and more quantitative understanding based both experimental and theoretical ...

International Nuclear Information System (INIS)

... 5. Formation of the annular two-phase flow regime, with a wavy film on the

Science.gov (United States)

... with the ability to capture imagery in raw 24-bit format, combined with large memory storage devices enable high resolution imagery to be captured ...

British Library Electronic Table of Contents (United Kingdom)

The early Miocene Pedregoso Formation is one of the numerous formations rich in organic matter within the stratigraphic record of the Urumaco Trough, in the central area of the Falcon Basin. Due to its lithological characteristics and stratigraphic position, this formation is of great interest regarding the basin's petroliferous systems. The evaluation of various inorganic and organic geochemical parameters indicates that the organic matter is primarily of marine origin, deposited in a marine carbonate environment typical of reefal systems, under oxic-to-dysoxic conditions. The low variability in the TOC concentrations and in the distributions of the biomarkers extracted from the samples suggests that the paleoenvironmental conditions and the organic-matter supply remained approximately co...

Science.gov (United States)

... gap" between the arrival ofquick response forces, such as the 82nd Airborne Division and the ... nd Airborne is just exactly that, light airborne infantry. ...

International Nuclear Information System (INIS)

The mechanism proposed by Kormendy (1984) for the formation of counterrotating cores in elliptical galaxies is investigated using self-consistent numerical simulations of mergers between a high- and a low-luminosity elliptical galaxies. The conditions for a counterrotation to appear are determined, observational properties of the remnants are described, and the evolution of the structural and kinematic parameters of the larger galaxy is analyzed. It is shown that a counterrotation results only when the merging orbits are retrograde, due to a large change in the secondary spin during the merger. 36 refs.

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We have examined in detail the electrochemistry of both n- and p-type single crystal (100) silicon in the porous silicon formation regime using a rotating Si disk apparatus with a Ag/AgCl reference electrode. Our findings impact the use and optimization of buried n- or p-type layer anodization for silicon-on-insulator (SOI) wafer synthesis. Results are briefly discussed. 3 refs.

British Library Electronic Table of Contents (United Kingdom)

Abstract A diacrylate polysulfone oligomer is synthesized and used as the acrylic oligomer for the in situ synthesis of noble metal/PSU nanocomposites through UV-induced simultaneous radical polymerization of acrylic functionalities and NP formation by reduction of their precursors. Thus, silver or gold NPs are formed in situ during polymer network formation. FESEM analysis of the morphology of the cured systems demonstrates that the nanoparticles of the noble metals are homogeneously distributed in the network without macroscopic agglomeration.

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High pressure experiments in a jet-stirred reactor have been performed to study the NO{sub x} formation in lean premixed combustion of methane/air mixtures. The experimental results are compared with numerical predictions using four well known reaction mechanisms and a model which consists of a series of two perfectly stirred reactors and a plug flow reactor. (author) 2 figs., 7 refs.

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The complex formation of zirconium with biphenyl mono- and biscatecholyazo derivatives has been studied spectrophotometrically. The composition of the complexes, form and charge of complex-forming zirconium ions have been established. A procedure is suggested for calculation of molar absorptivities and stability constants for each of the complexes formed simultaneously in the system. Possible complex formation schemes have been studied. The data obtained were used to develop a spectrophotometric method of determining zirconium in the presence of large amounts of copper.

International Nuclear Information System (INIS)

Radioactive "3"1Si(Tsub(1/2) = 2.62 h) and Rutherford backscattering were used to study Ni_2Si, Pd_2Si and Pt_2Si formation, silicon self-diffusion in silicides and silicon epitaxy in the Si(100)/Pd_2Si/Si (amorphous) system. (Auth.).

British Library Electronic Table of Contents (United Kingdom)

E-beam and gamma products from the radiolysis of aqueous solutions of (+-)-metoprolol tartrate, saturated in nitrogen, are analyzed by HPLC with on-line mass and UV detectors. The structures of 10 radiolytic products common to e-beam and gamma irradiations are elucidated by comparing their fragmentation pattern to that of (+-)-metoprolol. Two of the radiolytic products are also metabolites. Different routes for the formation of the radiolytic products are proposed.

International Nuclear Information System (INIS)

Recent observations of the evolutionary properties of paired and interacting galaxies are reviewed, with special emphasis on their global emission properties and star formation rates. Data at several wavelengths provide strong confirmation of the hypothesis, proposed originally by Larson and Tinsley, that interactions trigger global bursts of star formation in galaxies. The nature and properties of the starbursts, and their overall role in galactic evolution are also discussed.

Energy Technology Data Exchange (ETDEWEB)

The emission of hammer fragments in inelastic collisions of carbon nuclei at 3.6 GeV/nucleon with the nuclei of a photographic emulsion has been studied experimentally. The results show that the formation of these fragments is determined primarily by the extent to which the heavy target nucleus breaks up and does not depend directly on the mass of the incident nucleus.

Energy Technology Data Exchange (ETDEWEB)

The Sulige gas field and the Yulin gas field are located in the north of the Ordos Basin. Reservoir pressure in the Sulige area is subnormal, whereas reservoirs in the Yulin area have normal hydrostatic pressure. This paper provides an explanation of this difference. The characteristics of reservoir sediment and formation water chemistry in the gas reservoirs of these two areas were analyzed. The results showed that both reservoirs have good sealing ability. Data of numerical simulation showed that tectonic uplift resulted in a great reduction in formation pressure in the northern Ordos Basin during the late Cretaceous period, and the decrease was greater in the Yulin gas field than in the Sulige gas field. However, because the total hydrocarbon-generating intensity of the Sulige area (< 24 x 10{sup 8} m{sup 3}/km{sup 2}) was less than that of the Yulin area (> 32 x 10{sup 8} m{sup 3}/km{sup 2}), the gas supply intensity of the ...

UK PubMed Central (United Kingdom)

Mutations of ephrin B1 in humans result in craniofrontonasal syndrome. Because little is known of the role and mechanism of action of ephrin B1 in bone, we examined the function of osteoblast-produced...Full Text Available

UK PubMed Central (United Kingdom)

The influence of exogenous indole-3-acetic acid (IAA) and indole-3-butyric acid (IBA) on the internal levels of these auxins was studied during the first 4 days of adventitious root formation in cuttings...Full Text Available

International Nuclear Information System (INIS)

Proceeding from analysis of the influence of parameters of the target-filter system on radiation-physical characteristics of braking radiation, some recommendations were issued for assessment of the forming systems of medical accelerators of electrons. A new criterion - a coefficient of the forming system efficacy - was introduced, characterizing a beam formation tract with relation to a whole set of radiotherapeutic problems.

Energy Technology Data Exchange (ETDEWEB)

Changes in radiostrontium clearance (SrC) and bone formation (tetracycline labeling) were observed in the femurs of skeletally mature dogs following the various operative steps involved in bone screw fixation. Drilling, but not periosteal stripping, produced a small but statistically significant increase in SrC and endosteal bone formation in the distal third of the bone. Strontium clearance values equivalent to those produced by drilling alone were recorded after screw fixation at low or high torque (5 versus 20 inch pounds), as well as by the insertion of loosely fitting stainless steel implants. Bone formation (equals the percentage tetracycline-labeled trabecular bone surfaces) was increased by 30% when SrC values exceeded 3.5 ml/100 g bone/min, and the relationship was linear when SrC values ranged between 1.0 and 7.0 ml/100 g bone/min. The changes in SrC and bone formation one-week after bone ...

International Nuclear Information System (INIS)

In situ spectroscopic ellipsometry was employed to investigate the initial regime of rare earth metal (REM) conversion coatings formation on AZ31 magnesium alloy. Three REM salts solutions, 0.05 mol.dm"-"3 Ce(NO_3)_3, La(NO)_3 and Sm(NO)_3 solutions, were used for REM conversion coatings preparation. By deconvoluting the ellipsometric data, the surface of the fresh well-polished AZ31 magnesium alloy was found to be covered with 15.80 nm thick native (hydr)oxide film; the refractive indices and the thickness of Ce, La and Sm conversion coatings were obtained. The formation kinetics of three REM coatings follows different exponential functions and the coatings exhibit different optical properties. La conversion coating has the largest n values and the lowest k values while Sm conversion coating is just opposite. Moreover, the pH variation of the bulk conversion solutions upon the coatings formation was recorded. It is ...

Energy Technology Data Exchange (ETDEWEB)

The geology and resources of the lower Yellow Creek area, an area at the northwestern margin of the Piceance Creek basin comprising of four 7.5-minute quadrangles, are described. Subsurface face rocks penetrated by drill holes range in age from Pennsylvania to Cretaceous. Measured sections show the Mancos Shale and the Castlegate Sandstone, Iles Formation, and Williams Fork Formation of the Mesaverde Group of Late Cretaceous age and the Fort Union, Wasatch, Green River, and Uinta formations of Tertiary age. Surficial deposits of Quaternary age include terrace gravels, alluvium, and landslides. Fold axes and faults in the area trend northwesterly. The southern part of the area contains major oil-shale resources. Coal-bearing zones in the Williams Fork and Iles formations contain considerable coal. The coal-resources potential is limited, however, by nonpersistence of the thicker coal beds. Small amounts ...

International Nuclear Information System (INIS)

The formation kinetics of Pd_2Si for fully silicided (FUSI) gate formation and the work function tuning of a Pd_2Si FUSI gate by impurity predoping were investigated. It has been found that the morphology and phase of a formed FUSI layer depend not only on the silicidation annealing temperature but also on the heating ramp-up rate and the presence of impurities. Fast ramp-up annealing was necessary to avoid defect formation, such as voids in the silicide film at the oxide interface, and to obtain a homogeneous silicide film containing only Pd_2Si phase. The most severe effect on the silicidation reaction, that is the increase in defect formation, was brought about by As predoping. The work function of the Pd_2Si FUSI gate was modulated by impurity pileup at the Pd_2Si/SiO_2 interface, as in the case of the NiSi FUSI gate. However, the work function shifted in the opposite direction to that of the NiSi ...

Energy Technology Data Exchange (ETDEWEB)

The pilot area of the Vyngapour oil field allotted for MIOR tests contains three injection and three producing wells. These wells were treated in summer 1993 and 1994. Before, during, and after MIOR treatments on the pilot area the chemical compounds of injected and formation waters were studied, as well as the amount and species of microorganisms entering the stratum with the injected water and indigenous bacteria presented in bottomhole zones of the wells. The results of monitoring showed that the bottomhole zone of the injection well already had biocenosis of heterotrophic, hydrocarbon-oxidizing, methanogenic, and sulfate-reducing bacteria, which were besides permanently introduced into the reservoir during the usual waterflooding. The nutritious composition activated vital functions of all bacterial species presented in the bottomhole zone of the injection well. The formation waters from producing wells showed the increase of the content of ...

Energy Technology Data Exchange (ETDEWEB)

Purpose: To determine the value of MRI in the postoperativ evaluation of a singular ventricle compared to echocardiography and cardiac catheterization. Materials and methods: Thirty-one patients (range: 6 months to 30 years) with a functional single ventricle following palliative corrective operations. Five patients had a Blalock-Taussig-Shunt, 8 patients a Glenn-Anastomosis and 18 a cavopulmonary shunt (6 with classic Fontan-Circulation, 12 with modified cavopulmonary anastomosis). The results in terms of postoperative morphologic changes were compared to percutaneous echocardiography (31/31) and cardiac catheterization (6/31). Results: Echocardiography, which was performed on all patients, could not visualize the entire length of the tunnel, the Glenn-Anastomosis or the central pulmonary arteries in 70% of the patients due to an inadequate acoustic window. MRI was able to show the entire tunnel in 11/12 patients and the central pulmonary arteries in 30/31 ...

International Nuclear Information System (INIS)

Innumerable fissures were formed widely in Hanshin area in Japan by the former southern Hyogo prefectural earthquake occurred on Jan.17, 1995. In this study, as a preliminary investigation, we applied passive type radon detector Pico-Rad (U.S. Packard Instrument Co. Ltd.) with hemispheric plastic cover over them around the fissure along on the bank of two reservoirs to examine whether there is possibility to find fissures using the characteristics of "2"2"2Rn migration. One of the reservoir, Taniyamakami-ike, is located at the north of the Awaji-shima island at a distance of about 4 km from the seismic center of this earthquake. On the whole, "2"2"2Rn exhalation rates were high on a line of 2 m below the edge of the bank and got lower in proportion to the distance from this line. Those top of the bank had middle values among the lines. The mean "2"2"2Rn exhalation rate was 4.7 mBq m"-"2 s"-"1, and in these data we found some singularly high "2"2"2Rn points. The ...

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The Fredericksberg of South Florida may have a great oil potential that has been overlooked as a primary target in past decades. Previous exploration in the area has targeted the Lower Cretaceous oil-producing Sunniland Formation lower in the stratigraphic section. The Fredericksberg Dollar Bay Formation has hydrocarbon shows in many wells occurring in limestone biohermal deposits as well as in an upper dolomitic section. The Dollar Bay Formation is part of the Big Cypress Group of the Comanchean Series of the Lower Cretaceous. The Lower Cretaceous lithology is composed of evaporitic-carbonate cycles consisting of anhydrites, dolomites, and limestones. There are also present some calcareous shales, mudstones, salt, lignitic material, and carbonaceous material, especially in the anhydrite and limestone intervals. The limestones are usually micritic, chalky, calcarenitic, sometimes argillaceous, containing skeletal particles ...

International Nuclear Information System (INIS)

We investigate the relationship between spiral arms and star formation in the grand-design spirals NGC 5194 and NGC 628 and in the flocculent spiral NGC 6946. Filtered maps of near-IR (3.6 #mu#m) emission allow us to identify 'arm regions' that should correspond to regions of stellar mass density enhancements. The two grand-design spirals show a clear two-armed structure, while NGC 6946 is more complex. We examine these arm and interarm regions, looking at maps that trace recent star formation-far-ultraviolet (GALEX NGS) and 24 #mu#m emission (Spitzer SINGS)-and cold gas-CO (HERACLES) and H I (THINGS). We find the star formation tracers and CO more concentrated in the spiral arms than the stellar 3.6 #mu#m flux. If we define the spiral arms as the 25% highest pixels in the filtered 3.6 #mu#m images, we find that the majority (60%) of star formation tracers occur in the interarm regions; this result ...

British Library Electronic Table of Contents (United Kingdom)

Wavy interface morphology is observed in Magnetic Pulse Welding (MPW) similarly to that of the Explosion Welding process (EXW). It is recognized that interfacial waves are formed in a periodic manner and have well defined wavelength and amplitude. The phenomenon of wave formation in EXW has been subjected to extensive investigations in which empirical and numerical models have been published. In the present study, a wave formation mechanism for MPW is presented. This wave-creation mechanism was studied by evaluating the influence of sample geometry on wave morphology using stereoscopic optical microscopy. It was found that interfacial waves are formed in a Kelvin-Helmholtz instability mechanism. Reflected shock waves interact with the welding collision point at the weld interface, where in...

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The thermal spike model has been successfully applied to track formation by swift heavy ions in insulators. Arguments are given supporting the assumption that the thermal spike mechanism is also valid for the anisotropic growth. The glass transition temperature is used as the main thermal parameter of the amorphous solids. Experimental results on the track formation in {alpha}-quartz and in crystalline Ni{sub 3}B and also on the anisotropic growth in Pyrex and Synsil glasses, in amorphous Pd{sub 80}Si{sub 20}, Ni{sub 3}B and Fe{sub 85}B{sub 15} are discussed. Good agreement is found with the predictions of the thermal spike model. (orig.).

International Nuclear Information System (INIS)

Interaction of W(6) with sulphonaphtholazoresorcinol (SNAR) in aqueous solution has been studied. Tungsten is determined in the form of sulphonaphtholazoresorcinate by extraction with higher alcohols. The optimum conditions for the formation of a complex of W with SNAR in aqueous solution are as follows: a 10-fold excess of SNAR, concentration of HCl 1-1.5N, ethanol content 5-10 vol.%, time of formation of the complex 30 min. A component ratio for the complex has been established in the case of aqueous solution and extract; molar extinction coefficients are 0.9x10"4 and 1.7x10"4, respectively. The formation constant for the complex being extracted is 2.2x10"2"3. A method has been developed for determination of microgram quantities of W in a vanadium specimen.

International Nuclear Information System (INIS)

With the preeminence of A-15 superconducting multifilamentary wires in magnet technology, it has become important to understand the thermodynamic factors influencing the formation of these compounds under solid-state reaction conditions. The six systems Nb--Sn, Nb--Ga, Nb--Ge, Nb--Al, V--Si, and V--Ga were prepared as single filament bronze wires and heat treated in an attempt to precipitate the appropriate A-15 compound. The compounds observed to form were categorized using a formation temperature ratio (stability index) based on the melting temperatures of the constituents which make up the single filament composites. This study has led to several predictions regarding the formation of A-15 compounds using a solid-state bronze diffusion technique. The results of experimentation based on these predictions are presented.

British Library Electronic Table of Contents (United Kingdom)

ABSTRACT Shallow-lacustrine delta deposits of the Upper Triassic Yanchang Formation form the most important petroleum reservoir sandstone units in the Ordos Basin, China. Recent hydrocarbon exploration and outcrop studies demonstrated that shallow-lacustrine sand-rich deltas developed extensively along the gentle flanks and central part of the basin. The vertical succession of facies indicates that the Yanchang Formation records the entire lacustrine life cycle of the Late Triassic Ordos Basin. Four third-order transgressive-regressive cycles and two larger shallow-lacustrine deltaic cycles have been recognized. A process-based depositional model, derived in part from the modern Ganjiang delta in Poyang Lake, China, is used to infer the origins of the sand-rich lacustrine delta deposits. S...

CERN Document Server

Dusty primordial disks surrounding young low-mass stars are revealing tracers of stellar and planetary formation. The evolution and lifetime of these disks define the boundary conditions of the mechanisms of planet formation. Stellar companions, however, can significantly change this evolution through their tidal interactions. Stellar evolution and planet formation in binaries have to respond to an environment of truncated, quickly disappearing disks--very different compared to an isolated star environment. In order to investigate details of the influence of binarity on circumstellar disk evolution, we obtained adaptive optics supported near-infrared imaging and spectroscopy of the individual components of 22 low-mass binaries in the well-known Orion Nebula Cluster. Brackett gamma emission, which we detect in several systems, is used as a tracer for the presence of an active accretion disk around each binary component. We ...

British Library Electronic Table of Contents (United Kingdom)

The present study is focused on preparation of nano composite materials and the effect of citric acid on their different properties. The formation of nano HA and its interaction with chitosan (C), gelatin (G) polymers and citric acid (CA) materials were studied. The Fourier Transformed Infrared Spectroscopy (FT-IR), X-ray diffraction (XRD), thermo-gravimetric analysis (TGA), transmission electron microscope (TEM), and scanning electron microscope (SEM) were used to characterize these composite materials. The compressive strength (CS) was also measured to know the reinforcement of the prepared composites. The results show that carboxylic and amino groups play crucial role for HA formation on chitosan-gelatin polymeric matrix in the presence of citric acid (CA). The formation of nano HA part...

International Nuclear Information System (INIS)

Ozone production in a negative corona discharge has been studied experimentally at atmospheric pressure in mixtures of N_2O+O_2 at ambient temperature. Ozone formation was found to be dramatically reduced with increase in the content of N_2O in the mixture. The reaction of O("1D) with nitrous oxide is the most likely process reducing the rate of ozone generation. A considerable decrease in the mean discharge current at a constant voltage was also observed with increasing content of nitrous oxide in the mixture and is attributed to the formation of anions in the discharge. The low values of the calculated mobility of negative charge carriers in the drift region of the discharge is caused by the formation of O"- #centre dot# (N_2O)_n and NO"-#centre dot#(N_2O)_n cluster anions in the drift region of the negative corona discharge.

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Oil shales of the US represent a tremendous store of potential oil. Most of the deposits are relatively unknown and warrant additional investigation. The summary presented cannot hope to cover all of the deposits. Information about them is usually available only locally. However, the 3 best known deposits - the Green River formation, the Devonian black shales, and the retort member of the Phosphoria formation - represent well over 2 trillion bbl (300 x 10/sup 12/ ton) of potential oil in place. This is an oil resource large enough to supplement quite adequately the US petroleum supply, to extend the time available for realigning our energy supply mixes, and to help reach a satisfactory solution to our current energy dilemma. The concentrated resource in the Green River formation is obviously the next most feasible source of oil. If it cannot be developed, all the other deposits will have to wait until it can be. 100 ...

International Nuclear Information System (INIS)

With the assistance of mechanical activation, yttrium-stabilized #alpha#-SiAlON was prepared by combustion synthesis in air, instead of high-pressure N_2 atmosphere for the first time. The reaction activity of metallic particles was remarkably enhanced by mechanical activation, which conduced the reduction of grain size, increased the total surface area and formation of fresh surface. The formation of #alpha#-SiAlON by combustion synthesis in air was explained by a kinetically induced reaction mechanism, in which both initial formation of #alpha#-SiAlON and following avoidance of oxidation were fulfilled by the retardation of O_2 infiltration owing to the short reaction period and fast cooling rate.

British Library Electronic Table of Contents (United Kingdom)

Abstract We use Smoothed Particle Hydrodynamics to simulate the formation of a massive (106-M-) stellar cluster system formed from the gravitational collapse of a turbulent molecular cloud. We investigate the hierarchical clustering properties of our model system and we study the influence of the photoionizing radiation produced by the system's multiple O-type stars on the evolution of the protocluster. We find that dense gas near the ionizing sources prevents the radiation from eroding the filaments in which most of the star formation occurs and that instead, ionized gas fills pre-existing voids and bubbles originally created by the turbulent velocity field.

International Nuclear Information System (INIS)

By applying the high-resolution sequence stratigraphy, the different sub-divisions of base-level cycles of Qingtujing Formation, Middle Jurassic in Chaoshui Basin are analyzed in detail. 23 short, 3 middle and 1 long base-level cycles are recognized. On the above basis, the corresponding frameworks of high-resolution sequence stratigraphy have been established in northern and southern sub-basins respectively, and the detailed sedimentary facies of MSC_1_-_3 and the special distribution of Qintujing Formation are discussed. It is pointed out that MSC_2 is the most favorable layer for the localization of sandstone-type uranium deposits. (authors)

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This communication reports the formation of complex Langmuir monolayer at the air-water interface by charge transfer types of interaction with the water soluble N-cetyl Formula Not Shown -trimethyl ammonium bromide (CTAB) molecules doped with rosebengal (RB), with the stearic acid (SA) molecules of a preformed SA Langmuir monolayer. The reaction kinetics of the formation of RB-CTAB-SA complex monolayer was monitored by observing the increase in surface pressure with time while the barrier was kept fixed. Completion of interaction kinetics was confirmed by FTIR study. This complex Langmuir films at the air-water interface was transferred onto solid substrates at a desired surface pressure to form multilayered Langmuir-Blodgett films. Spectroscopic characterizations reveal some molecular lev...

British Library Electronic Table of Contents (United Kingdom)

Abstract Therapeutic proteins are exposed to various potential contact surfaces, particles, and leachables during manufacturing, shipping, storage, and delivery. In this review, we present published examples of interfacial- or leachable-induced aggregation or particle formation, and discuss the mitigation strategies that were successfully utilized. Adsorption to interfaces or interactions with leachables and/or particles in some cases has been reported to cause protein aggregation or particle formation. Identification of the cause(s) of particle formation involving minute amounts of protein over extended periods of time can be challenging. Various formulation strategies such as addition of a nonionic surfactant (e.g., polysorbate) have been demonstrated to effectively mitigate adsorption-i...

British Library Electronic Table of Contents (United Kingdom)

The Yaojia Formation recovered by CCSD-SK-Is borehole (China Cretaceous Continental Scientific Drilling-SongkeI-the south borehole) is 157.67 m long and 99.96% of cores recovery. The age of the formation corresponds with a range from the Santonian to the early Campanian. The sequences and processes of lithology-lithofacies and cyclic stratigraphy are revealed by a detailed core description. Eleven rock types and three kinds of sedimentary subfacies, including shallow lake, deep lake, and delta front, are recognized from the drilling core. There are eleven sedimentary microfacies including dolostone, argillaceous limestone, shallow lake turbidite, deep lake turbidite, subaqueous mouth bar, distal bar, sheet sandstone, subaqueous distributary bay, slump deposits, shallow lake mudstone, and d...

British Library Electronic Table of Contents (United Kingdom)

The first member of the Qingshankou Formation recovered by CCSD-SK-Is borehole (China Cretaceous Continental Scientific Drilling-SongkeI-the south borehole) is 81.41 m long, and the recovery of cores is 100%. The age of the member is approximately Turonian. The sequence and process of lithology-lithofacies and cyclic stratigraphy were revealed by a detailed core description. 6 rock types (mudstone, dolomite, marl, limestone, ostracode limestone, and volcanic ash) comprise the sedimentary strata. Deposition occurred in a deep lake, including 6 sedimentary microfacies: mudstone, sandy turbidite, dolomite, marl, limestone, and volcanic ash microfacies. The first member of the Qingshankou Formation represents 81 meter-scale cycles (sixth-order cycle), 25 fifth-order cycles, 6 fourth-order cycl...

British Library Electronic Table of Contents (United Kingdom)

Fyn is a Src-family tyrosine kinase that affects long term potentiation (LTP), synapse formation, and learning and memory. Fyn is also implicated in dendritic spine formation both in vitro and in vivo. However, whether Fyn's regulation of dendritic spine formation is brain-region specific and age-dependent is unknown. In the present study, we systematically examined whether Fyn altered dendritic spine density and morphology in the cortex and hippocampus and if these effects were age-dependent. We found that Fyn knockout mice trended toward a decrease in dendritic spine density in cortical layers II/III, but not in the hippocampus, at 1month of age. Additionally, Fyn knockout mice had significantly decreased dendritic spine density in both the cortex and hippocampus at 3months and 1year, an...

Energy Technology Data Exchange (ETDEWEB)

It has been shown by recent experiments that bulk immiscible metals (e.g. Ag/Cu, Ag/Co and Au/Ni) can form binary alloys on certain surfaces where the substrate mediates the elastic misfits between the two components, thus relieving the elastic strain in the overlayer. These novel surface alloys exhibit a rich phase structure. We formulate a two-component Frenkel-Kontorova model in one dimension to study surface alloy formation. This model can naturally incorporate dislocation formation that plays a crucial role in determining the actual structure of the system. Using energy minimization calculations we provide a phase diagram in terms of average alloy composition and the energy of mixing. Monte Carlo simulations were also performed to study the structure and interaction of the emerging dislocations.

UK PubMed Central (United Kingdom)

Somite boundary formation is crucial for segmentation of vertebrate somites and vertebrae and skeletal muscle morphogenesis. Previously, we developed a Tol2 transposon-mediated...Full Text Available

UK PubMed Central (United Kingdom)

Select members of the Reoviridae are the only nonenveloped viruses known to induce syncytium formation. The fusogenic orthoreoviruses accomplish cell-cell fusion through a distinct...Full Text Available

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PurposeHeavy metals and other forms of oxidative stress have been implicated as key factors in the formation of age-related cataract in humans. Metallothioneins are...Full Text Available

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The rolB gene of Agrobacterium rhizogenes, whose expression stimulates the formation of roots by transformed plant tissues and other growth alterations in transgenic plants, codes for a beta-glucosidase...Full Text Available

UK PubMed Central (United Kingdom)

The formation and maintenance of social bonds in adulthood is an essential component of human health. However studies investigating the underlying neurobiology of such behaviors have been scarce....Full Text Available

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The formation of textured YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} (123) from a liquid phase according to the peritectic reaction Y{sub 2}BaCuO{sub 5} (211) + liquid {yields} 123 was analyzed using real-time analysis techniques of high-temperature X-ray diffraction, high-temperature optical microscopy, and environmental scanning electron microscopy (ESEM). Results were coupled with conventional ''post-mortem'' SEM analysis of processed samples at various stages of microstructural development. Observations of 123 formation and growth from the peritectic melt permit the conclusion that the presence of crystalline 211 primarily acts as a source of yttrium. The slow dissolution of 211 into the yttrium deficient liquid phase is the rate controlled step in the formation and growth of the textured 123, rather that its acting as a nucleation site for 123 grains as has been widely assumed. (orig.).

Science.gov (United States)

Analytical relations are obtained for estimating how the distributions of temperature and heat flux vary along a steam-generating tube and how the steam-generator power output reduces due to formation and accumulation of deposits.

International Nuclear Information System (INIS)

The carbothermal reduction of clay minerals in a nitrogen atmosphere is a well established method for producing #beta#'-sialon. There has been some debate within the literature concerning the role that Fe plays in the formation of the #beta#'-sialon phase. However, most workers accept that Fe is able to either catalyze or promote the formation of #beta#'-sialon although some workers have indicated that the function of the Fe is controlled by gas flow rate and there is evidence that Fe also promotes formation of additional phases. The aim of the present study was to characterize the behaviour of Fe within the #beta#'-sialon synthesis. "5"7Fe Moessbauer spectroscopy was employed for the study because this technique is specific to Fe and does not suffer interference from other elements. Moreover, both the coordination and oxidation state and the relative abundances of the various Fe-containing phases are able to be monitored. ...

CERN Document Server

We study the structure of the medium surrounding sites of high-mass star formation to determine the interrelation between the HII regions and the environment from which they were formed. The density distribution of the surroundings is key in determining how the radiation of the newly formed stars interacts with the surrounds in a way that allows it to be used as a star formation tracer. We present new Herschel/SPIRE 250, 350 and 500 mum data of LHA 120-N44 and LHA 120-N63 in the LMC. We construct average spectral energy distributions (SEDs) for annuli centered on the IR bright part of the star formation sites. The annuli cover ~10-~100 pc. We use a phenomenological dust model to fit these SEDs to derive the dust column densities, characterise the incident radiation field and the abundance of polycyclic aromatic hydrocarbon molecules. We see a factor 5 decrease in the radiation field energy density as a function of radial ...

UK PubMed Central (United Kingdom)

The fungal pathogen Candida albicans is one of the leading causative agents of death in immunocompromised individuals. It harbors an arsenal of cell wall anchored factors that are implicated...Full Text Available

Science.gov (United States)

tial/angular spreading of incident photons from a point source caused by the instrument (de- .... Filter. CDTP0001= 'DATA. ' / Type of calibration. CCNM0001= '2D_PSF ' ... the final resolution of sigma=0.5 arcmin in all energy bands. ...

UK PubMed Central (United Kingdom)

Cysticercosis is an infection with larval cysts of the cestode Taenia solium. Through pathways that are incompletely understood, dying parasites initiate a granulomatous reaction that,...Full Text Available

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Septa can be demonstrated in sections of Escherichia coli strains B and B/r after fixation with acrolein and glutaraldehyde. The septum consists of an ingrowth of the cytoplasmic membrane...Full Text Available

UK PubMed Central (United Kingdom)

Human chromosomal fragile sites are specific loci that are especially susceptible to DNA breakage following conditions of partial replication stress. They often are found in genes involved in tumorigenesis...Full Text Available

UK PubMed Central (United Kingdom)

Adult meadow voles (Microtus pennsylvanicus) are solitary in the spring–summer reproductive season, but during winter months, females and males are socially tolerant...Full Text Available

UK PubMed Central (United Kingdom)

Target of rapamycin (TOR) kinases control cell growth through two functionally distinct multiprotein complexes. TOR complex 1 (TORC1) controls temporal cell growth and is sensitive to rapamycin, whereas...Full Text Available

UK PubMed Central (United Kingdom)

Extracts of Chlorella pyrenoidosa, Euglena gracilis var. bacillaris, spinach, barley, Dictyostelium discoideum and Escherichia coli...Full Text Available

UK PubMed Central (United Kingdom)

Eukaryotic cells can massively transport their own cytoplasmic contents into a lytic compartment, the vacuole/lysosome, for recycling through a conserved system called autophagy. The key process in...Full Text Available

UK PubMed Central (United Kingdom)

The rate and capacity for chloroform (CF) and trichloroethylene (TCE) transformation by a mixed methanotrophic culture of resting cells (no exogenous energy source) and formate-fed cells were measured....Full Text Available

UK PubMed Central (United Kingdom)

Recent experiments have provided new quantitative measurements of the rippling phenomenon in fields of developing myxobacteria cells. These measurements have enabled us to develop a mathematical model...Full Text Available

Science.gov (United States)

KDZ@PEDEL@6RRD>ME0HBF?73 96:IE4K?8814# &=83J46:7A4;/??/D;69>B,F=9>E6L@8A82? ...

UK PubMed Central (United Kingdom)

BackgroundIn this study we investigated the predictability of three thermodynamic quantities related to complex formation. As a model system we chose the host-guest complexes of...Full Text Available

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The Lander Quadrangle, Wyoming, was evaluated to a depth of 1500 m to identify environments and delineate areas that exhibit characteristics favorable for the the occurrence of uranium deposits. The evaluation used criteria established for the National Uranium Resources Evaluation program. The methods of surface investigations included evaluation of aerial radiometric and hydrogeochemical stream-sediment reconnaissance data, verification of some reported uranium occurrences, and general field geology with rock, water, and sediment sampling. The subsurface evaluation was accomplished through the use of 230 various oil-well logs. The results of this investigation identified three environments favorable for sandstone uranium deposits in Eocene fluvial sediments. These environments are within the Battle Spring and upper Fort Union Formations of the northern Great Divide Basin and within the Wind River and the Wagon Bed Formations of the southwest ...

UK PubMed Central (United Kingdom)

AimsThe efficacy of topical glucocorticosteroids in rhinitis and asthma is likely to depend on drug retention in the airway mucosa. With fluticasone propionate, retention may be...Full Text Available

UK PubMed Central (United Kingdom)

The origin of myofibroblasts or myofibroblastic cells in the desmoplastic stroma associated with carcinoma invasion has been controversial. In the early invasive area of a rectal adenocarcinoma reported...Full Text Available

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A numerical model was developed to simulate the combined effects of heat transfer, magnetite oxidation, and NO{sub x} formation in a grate-kiln furnace for taconite pellet induration. Heat transfer from the flame in the kiln was described by the net radiation method. The shrinking core model was used to account for magnetite oxidation on the grate. A novel approach to oxidation of tumbling pellets in a kiln was derived. The Zeldovich mechanism was used to predict thermal NO generation. Temperature fluctuations in the gas streams were estimated with a clipped Gaussian probability density function. The thermal energy balances and mass balances resulted in coupled systems of first-order differential equations, which were solved numerically. The model is capable of predicting NO production and magnetite oxidation in agreement with observation of plant performance. Although the design of the grate-kiln system is for efficient heat and mass transfer, it may not be the ...

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Method for inhibiting the formation of foulants on petrochemical equipment which involves adding to the petrochemical, during processing, a composition comprising a thiodipropionate and either a dialkyl acid phosphate ester or a dialkyl acid phosphite ester.

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The formation of mammalian secondary palate requires a series of developmental events such as growth, elevation and fusion. Despite recent advances in the field of palate development, the process...Full Text Available

International Nuclear Information System (INIS)

The formation of the melilite solid solution phase (M'), Sm_2Si_3_-_xAl_xO_3_+_xN_4_-_x, in an #alpha#-sialon sample of overall composition Sm_0_._6Si_9_._2_8Al_2_._6_9O_1_._3_6N_1_4_._7_6, was studied as a function of time in the temperature interval 1,375--1,525 C. The #alpha#-sialon ceramic contained only minor amounts of the 21R sialon polytype and some residual grain-boundary glass before heat treatment. In situ studies by high-temperature X-ray diffraction were combined with postsintering heat treatment followed by quenching. The M'-phase was found to be formed by two different mechanisms: either crystallization of the residual grain-boundary liquid or a direct decomposition of the #alpha#-sialon phase. The liquid crystallized during the first 10--15 min of heat treatment, yielding a rapid M'-phase formation, and further formation of M'-phase continued at a much slower rate, related to the decomposition of ...

UK PubMed Central (United Kingdom)

Polycystic kidney disease (PKD) is one of the leading causes of end-stage renal disease in humans and is characterized by progressive cyst formation, renal enlargement, and abnormal tubular development....Full Text Available

International Nuclear Information System (INIS)

A technique for following sialon formation in situ by high temperature X-ray diffraction (HT-XRD) was developed. The composition chosen for study was an yttrium #alpha#-sialon with x=0.4. Powder compacts containing silicon nitride, aluminum nitride and yttria powders were pre-sintered at 1350 C and then studied by HT-XRD at temperatures between 1450 and 1580 C and nitrogen pressures of 0.11 MPa. The furnace was made from graphite coated with porous silicon nitride/silicon carbide. The coating prevented silicon carbide formation in the sample up to 1600 C. X-ray diffraction results show the formation of a Y_1_0Al_2Si_3O_1_8N_4 phase at 1350 C, which dissolved to form #alpha#-sialon and other phases at higher temperatures. The amounts of #alpha#-sialon formed are similar to the amounts reported by other authors. An empirical method was used for the calculation of activation energy for the silicon nitride to #alpha#-sialon ...

UK PubMed Central (United Kingdom)

Sensory experience plays a crucial role in regulating neuronal shape and in developing synaptic contacts during brain formation. These features are required for a neuron to receive, integrate, and transmit...Full Text Available

UK PubMed Central (United Kingdom)

A mutation in a new gene, molR, prevented the synthesis in Escherichia coli of molybdoenzymes, including the two formate dehydrogenase isoenzymes, nitrate reductase and trimethylamine-N-oxide reductase....Full Text Available

UK PubMed Central (United Kingdom)

A nodulation plasmid, pRtr-514a, of molecular size 180 megadaltons (Mdal) was identified in Rhizobium trifolii strain NZP514. This plasmid was absent in both spontaneous and heat-cured Nod- derivatives...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

In the region of annular liquid film-mist flow, the behavior of the droplets formed from the liquid film and the rate of formation are the subjects to be clarified in connection with the forecast of dry-out point, which becomes a problem in the region of high dryness such as reactor cooling system and steam generators. Many researches have been performed on such problem in vertical tubes, but the characteristics in horizontal flow have not yet been sufficiently clarified. This series of research is to clarify various characteristics, such as the velocity of vapor phase, the flow rate distribution of droplets, the formation and adhesion of droplets and the structure of liquid film, in the region of liquid film-mist flow, where liquid film exists on the bottom of a horizontal rectangular channel, and vapor flow is accompanied by droplets. In this study, by the measurement of the flow rate distribution of droplets on respective cross sections ...

Science.gov (United States)

This monograph explores an alternative way of providing a JSOTF headquarters to the Joint Force Commander. Beginning with a history of joint SOF doctrine, the monograph outlines the evolution of special operations command and control and the subsequent ne...

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High-resolution near-infrared and far-infrared observations are presented of the southeastern molecular cloud fragment in the IC 5146 dark cloud. These observations rule out earlier suggestions for the formation of massive stars in this fragment.