Yukawa couplings in superstring compactification. [in quantum gravity theory

NASA Technical Reports Server (NTRS)

Strominger, A.

1985-01-01

A topological formula is given for the entire tree-level contribution to the low-energy effective action of a Calabi-Yau superstring compactification. The constraints on proton lifetime in the Calabi-Yau compactification are discussed in detail.

Some blackhole and compactification solutions of noncanonical global monopole in 4-dimensional spacetime

NASA Astrophysics Data System (ADS)

Prasetyo, I.; Ramadhan, H. S.

2017-07-01

Here we present some solutions with noncanonical global monopole in nonlinear sigma model in 4-dimensional spacetime. We discuss some blackhole solutions and its horizons. We also obtain some compactification solutions. We list some possible compactification channels from 4-space to 2 × 2-spaces of constant curvatures.

The anomalous U(1)_{anom} symmetry and flavors from an SU(5) × SU(5)' GUT in Z_{12-I} orbifold compactification

NASA Astrophysics Data System (ADS)

Kim, Jihn E.; Kyae, Bumseok; Nam, Soonkeon

2017-12-01

In string compactifications, frequently the anomalous U(1) gauge symmetry appears which belongs to E_8 × E_8' of the heterotic string. This anomalous U(1) gauge boson obtains mass at the compactification scale (≈ 10^{18 } {GeV}) by absorbing one pseudoscalar (corresponding to the model-independent axion) from the second rank antisymmetric tensor field B_{MN}. Below the compactification scale a global symmetry U(1)_{anom} results whose charge Q_anom is the original gauge U(1) charge. This is the most natural global symmetry, realizing the "invisible" axion. This global symmetry U(1)_{anom} is suitable for a flavor symmetry. In the simplest compactification model with the flipped SU(5) grand unification, all the low energy parameters are calculated in terms of the vacuum expectation values of the standard model singlets.

Gamma Rays from the Galactic Bulge and Large Extra Dimensions

NASA Astrophysics Data System (ADS)

Cassé, Michel; Paul, Jacques; Bertone, Gianfranco; Sigl, Günter

2004-03-01

An intriguing feature of extra dimensions is the possible production of Kaluza Klein gravitons by nucleon-nucleon bremsstrahlung, in the course of core collapse of massive stars, with gravitons then being trapped around the newly born neutron stars and decaying into two gamma rays, making neu­tron stars gamma-ray sources. We strengthen the limits on the radius of compactification of extra dimensions for a small number n of them, or alternatively the fundamental scale of quantum gravity, considering the gamma-ray emission of the whole population of neutron stars sitting in the Galactic bulge, instead of the closest member of this category. For n=1 the constraint on the compactification radius is R<400 μm.

A note on 4D heterotic string vacua, FI-terms and the swampland

NASA Astrophysics Data System (ADS)

Aldazabal, Gerardo; Ibáñez, Luis E.

2018-07-01

We present a conjecture for the massless sector of perturbative 4D N = 1 heterotic (0 , 2) string vacua, including U(1) n gauge symmetries, one of them possibly anomalous (like in standard heterotic compactifications). Mathematically it states that the positive hull generated by the charges of the massless chiral multiplets spans a sublattice of the full charge lattice. We have tested this conjecture in many heterotic N = 1 compactifications in 4D. Our motivation for this conjecture is that it allows to understand a very old puzzle in (0 , 2) N = 1 heterotic compactification with an anomalous U (1). The conjecture guarantees that there is always a D-flat direction cancelling the FI-term and restoring N = 1 SUSY in a nearby vacuum. This is something that has being verified in the past in a large number of cases, but whose origin has remained obscure for decades. We argue that the existence of a lattice generated by massless states guarantees the instability of heterotic non-BPS extremal blackholes, as required by Weak Gravity Conjecture arguments. Thus the pervasive existence of these nearby FI-cancelling vacua would be connected with WGC arguments.

AdS and dS Entropy from String Junctions or The Function of Junction Conjunctions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Silverstein, Eva M

Flux compactifications of string theory exhibiting the possibility of discretely tuning the cosmological constant to small values have been constructed. The highly tuned vacua in this discretuum have curvature radii which scale as large powers of the flux quantum numbers, exponential in the number of cycles in the compactification. By the arguments of Susskind/Witten (in the AdS case) and Gibbons/Hawking (in the dS case), we expect correspondingly large entropies associated with these vacua. If they are to provide a dual description of these vacua on their Coulomb branch, branes traded for the flux need to account for this entropy atmore » the appropriate energy scale. In this note, we argue that simple string junctions and webs ending on the branes can account for this large entropy, obtaining a rough estimate for junction entropy that agrees with the existing rough estimates for the spacing of the discretuum. In particular, the brane entropy can account for the (A)dS entropy far away from string scale correspondence limits.« less

Classical and quantum stability in putative landscapes

DOE PAGES

Dine, Michael

2017-01-18

Landscape analyses often assume the existence of large numbers of fields, N, with all of the many couplings among these fields (subject to constraints such as local supersymmetry) selected independently and randomly from simple (say Gaussian) distributions. We point out that unitarity and perturbativity place significant constraints on behavior of couplings with N, eliminating otherwise puzzling results. In would-be flux compactifications of string theory, we point out that in order that there be large numbers of light fields, the compactification radii must scale as a positive power of N; scaling of couplings with N may also be necessary for perturbativity.more » We show that in some simple string theory settings with large numbers of fields, for fixed R and string coupling, one can bound certain sums of squares of couplings by order one numbers. This may argue for strong correlations, possibly calling into question the assumption of uncorrelated distributions. Finally, we consider implications of these considerations for classical and quantum stability of states without supersymmetry, with low energy supersymmetry arising from tuning of parameters, and with dynamical breaking of supersymmetry.« less

Classical and quantum stability in putative landscapes

NASA Astrophysics Data System (ADS)

Dine, Michael

2017-01-01

Landscape analyses often assume the existence of large numbers of fields, N , with all of the many couplings among these fields (subject to constraints such as local supersymmetry) selected independently and randomly from simple (say Gaussian) distributions. We point out that unitarity and perturbativity place significant constraints on behavior of couplings with N , eliminating otherwise puzzling results. In would-be flux compactifications of string theory, we point out that in order that there be large numbers of light fields, the compactification radii must scale as a positive power of N ; scaling of couplings with N may also be necessary for perturbativity. We show that in some simple string theory settings with large numbers of fields, for fixed R and string coupling, one can bound certain sums of squares of couplings by order one numbers. This may argue for strong correlations, possibly calling into question the assumption of uncorrelated distributions. We consider implications of these considerations for classical and quantum stability of states without supersymmetry, with low energy supersymmetry arising from tuning of parameters, and with dynamical breaking of supersymmetry.

Physics from geometry: Non-Kahler compactifications, black rings anddS/CFT

NASA Astrophysics Data System (ADS)

Cyrier, Michelle

The spectrum that arises in four dimensions from compactification of ten dimensional string theory onto six dimensional manifolds is determined entirely by the geometry of the compactification manifold. The massless spectrum for compactifications on Calabi-Yau threefolds, which are Kahler and have complex structure, is well understood. In chapter 2 of this thesis, We study the compactification of heterotic string theory on manifolds that are non-Kahler. Such manifolds arise as a solution for compactifications of heterotic string theory with nonzero H-flux. We begin the study of the massless spectrum arising from compactification using this construction by counting zero modes of the linearized equations of motion for the gaugino in the supergravity approximation. We rephrase the question in terms of a cohomology problem and show that for a trivial gauge bundle, this cohomology reduces to the Dolbeault cohomology of the 3-fold, which we then compute. Another check of string theory is to study the entropy of black holes made in string theory. In Chapter 3, We review the microstate counting of four dimensional black holes made from M theory. We then describe a new solution in five dimensions, the supersymmetric black ring, and describe its microscopic entropy using a similar counting. These agree with the semi-classical Bekenstein-Hawking entropy for these black holes. Finally, one powerful tool for quantum gravity is the holographic duality of string theory in an Anti de Sitter background and a theory living on its conformal boundary. Strominger conjectured a similar duality between quantum gravity in a de Sitter background and the corresponding theory on its boundary. In chapter 4 we examine issues with different representations of the conformal field theory on the boundary for a massive quantum field theory living in the bulk and try to write down a sensible CFT.

From 6D superconformal field theories to dynamic gauged linear sigma models

NASA Astrophysics Data System (ADS)

Apruzzi, Fabio; Hassler, Falk; Heckman, Jonathan J.; Melnikov, Ilarion V.

2017-09-01

Compactifications of six-dimensional (6D) superconformal field theories (SCFTs) on four- manifolds generate a large class of novel two-dimensional (2D) quantum field theories. We consider in detail the case of the rank-one simple non-Higgsable cluster 6D SCFTs. On the tensor branch of these theories, the gauge group is simple and there are no matter fields. For compactifications on suitably chosen Kähler surfaces, we present evidence that this provides a method to realize 2D SCFTs with N =(0 ,2 ) supersymmetry. In particular, we find that reduction on the tensor branch of the 6D SCFT yields a description of the same 2D fixed point that is described in the UV by a gauged linear sigma model (GLSM) in which the parameters are promoted to dynamical fields, that is, a "dynamic GLSM" (DGLSM). Consistency of the model requires the DGLSM to be coupled to additional non-Lagrangian sectors obtained from reduction of the antichiral two-form of the 6D theory. These extra sectors include both chiral and antichiral currents, as well as spacetime filling noncritical strings of the 6D theory. For each candidate 2D SCFT, we also extract the left- and right-moving central charges in terms of data of the 6D SCFT and the compactification manifold.

Flux compactification of M-theory on compact manifolds with spin(7) holonomy

NASA Astrophysics Data System (ADS)

Constantin, Dragos Eugeniu

2005-11-01

At the leading order, M-theory admits minimal supersymmetric compactifications if the internal manifold has exceptional holonomy. The inclusion of non-vanishing fluxes in M-theory and string theory compactifications induce a superpotential in the lower dimensional theory, which depends on the fluxes. In this work, we check the conjectured form of this superpotential in the case of warped M-theory compactifications on Spin (7) holonomy manifolds. We perform a Kaluza-Klein reduction of the eleven-dimensional supersymmetry transformation for the gravitino and we find by direct comparison the superpotential expression. We check the conjecture for the heterotic string compactified on a Calabi-Yau three-fold as well. The conjecture can be checked indirectly by inspecting the scalar potential obtained after the compactification of M-theory on Spin (7) holonomy manifolds with non-vanishing fluxes. The scalar potential can be written in terms of the superpotential and we show that this potential stabilizes all the moduli fields describing deformations of the metric except for the radial modulus. All the above analyses require the knowledge of the minimal supergravity action in three dimensions. Therefore we calculate the most general causal N = 1 three-dimensional, gauge invariant action coupled to matter in superspace and derive its component form using Ectoplasmic integration theory. We also show that the three-dimensional theory which results from the compactification is in agreement with the more general supergravity construction. The compactification procedure takes into account higher order quantum correction terms in the low energy effective action. We analyze the properties of these terms on a Spin (7) background. We derive a perturbative set of solutions which emerges from a warped compactification on a Spin (7) holonomy manifold with non-vanishing flux for the M-theory field strength and we show that in general the Ricci flatness of the internal manifold is lost, which means that the supergravity vacua are deformed away from the exceptional holonomy. Using the superpotential form we identify the supersymmetric vacua out of this general set of solutions.

Effects on the CMB from compactification before inflation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kontou, Eleni-Alexandra; Blanco-Pillado, Jose J.; Hertzberg, Mark P.

2017-04-01

Many theories beyond the Standard Model include extra dimensions, though these have yet to be directly observed. In this work we consider the possibility of a compactification mechanism which both allows extra dimensions and is compatible with current observations. This compactification is predicted to leave a signature on the CMB by altering the amplitude of the low l multipoles, dependent on the amount of inflation. Recently discovered CMB anomalies at low multipoles may be evidence for this. In our model we assume the spacetime is the product of a four-dimensional spacetime and flat extra dimensions. Before the compactification, both themore » four-dimensional spacetime and the extra dimensions can either be expanding or contracting independently. Taking into account physical constraints, we explore the observational consequences and the plausibility of these different models.« less

Towards realistic string vacua from branes at singularities

NASA Astrophysics Data System (ADS)

Conlon, Joseph P.; Maharana, Anshuman; Quevedo, Fernando

2009-05-01

We report on progress towards constructing string models incorporating both realistic D-brane matter content and moduli stabilisation with dynamical low-scale supersymmetry breaking. The general framework is that of local D-brane models embedded into the LARGE volume approach to moduli stabilisation. We review quiver theories on del Pezzo n (dPn) singularities including both D3 and D7 branes. We provide supersymmetric examples with three quark/lepton families and the gauge symmetries of the Standard, Left-Right Symmetric, Pati-Salam and Trinification models, without unwanted chiral exotics. We describe how the singularity structure leads to family symmetries governing the Yukawa couplings which may give mass hierarchies among the different generations. We outline how these models can be embedded into compact Calabi-Yau compactifications with LARGE volume moduli stabilisation, and state the minimal conditions for this to be possible. We study the general structure of soft supersymmetry breaking. At the singularity all leading order contributions to the soft terms (both gravity- and anomaly-mediation) vanish. We enumerate subleading contributions and estimate their magnitude. We also describe model-independent physical implications of this scenario. These include the masses of anomalous and non-anomalous U(1)'s and the generic existence of a new hyperweak force under which leptons and/or quarks could be charged. We propose that such a gauge boson could be responsible for the ghost muon anomaly recently found at the Tevatron's CDF detector.

BPS Jumping Loci are Automorphic

NASA Astrophysics Data System (ADS)

Kachru, Shamit; Tripathy, Arnav

2018-06-01

We show that BPS jumping loci-loci in the moduli space of string compactifications where the number of BPS states jumps in an upper semi-continuous manner—naturally appear as Fourier coefficients of (vector space-valued) automorphic forms. For the case of T 2 compactification, the jumping loci are governed by a modular form studied by Hirzebruch and Zagier, while the jumping loci in K3 compactification appear in a story developed by Oda and Kudla-Millson in arithmetic geometry. We also comment on some curious related automorphy in the physics of black hole attractors and flux vacua.

Large trilinear At soft supersymmetry breaking coupling from 5D MSSM

NASA Astrophysics Data System (ADS)

Abdalgabar, Ammar; Cornell, A. S.

2015-10-01

The possibility of generating a large trilinear At soft supersymmetry breaking coupling at low energies through renormalisation group evolution in the 5D MSSM is investigated. Using the power law running in five dimensions and a compactification scale in the 10-103 TeV range, we show that gluino mass may drive a large enough At to reproduce the measured Higgs mass and have a light stop superpartner below ∼ 1 TeV, as preferred by the fine tuning argument for the Higgs mass.

Spin(7) compactifications and 1/4-BPS vacua in heterotic supergravity

NASA Astrophysics Data System (ADS)

Angus, Stephen; Matti, Cyril; Svanes, Eirik E.

2016-03-01

We continue the investigation into non-maximally symmetric compactifications of the heterotic string. In particular, we consider compactifications where the internal space is allowed to depend on two or more external directions. For preservation of supersymmetry, this implies that the internal space must in general be that of a Spin(7) manifold, which leads to a 1/4-BPS four-dimensional supersymmetric perturbative vacuum breaking all but one supercharge. We find that these solutions allow for internal geometries previously excluded by the domain-wall-type solutions, and hence the resulting four-dimensional superpotential is more generic. In particular, we find an interesting resemblance to the superpotentials that appear in non-geometric flux compactifications of type II string theory. If the vacua are to be used for phenomenological applications, they must be lifted to maximal symmetry by some non-perturbative or higher-order effect.

Standard 4D gravity on a brane in six-dimensional flux compactifications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Peloso, Marco; Sorbo, Lorenzo; Tasinato, Gianmassimo

We consider a six-dimensional space-time, in which two of the dimensions are compactified by a flux. Matter can be localized on a codimension one brane coupled to the bulk gauge field and wrapped around an axis of symmetry of the internal space. By studying the linear perturbations around this background, we show that the gravitational interaction between sources on the brane is described by Einstein 4D gravity at large distances. Our model provides a consistent setup for the study of gravity in the rugby (or football) compactification, without having to deal with the complications of a deltalike, codimension two brane.more » To our knowledge, this is the first complete study of gravity in a realistic brane model with two extra dimensions, in which the mechanism of stabilization of the extra space is fully taken into account.« less

An uplifting discussion of T-duality

NASA Astrophysics Data System (ADS)

Harvey, Jeffrey A.; Moore, Gregory W.

2018-05-01

It is well known that string theory has a T-duality symmetry relating circle compactifications of large and small radius. This symmetry plays a foundational role in string theory. We note here that while T-duality is order two acting on the moduli space of compactifications, it is order four in its action on the conformal field theory state space. More generally, involutions in the Weyl group W ( G) which act at points of enhanced G symmetry have canonical lifts to order four elements of G, a phenomenon first investigated by J. Tits in the mathematical literature on Lie groups and generalized here to conformal field theory. This simple fact has a number of interesting consequences. One consequence is a reevaluation of a mod two condition appearing in asymmetric orbifold constructions. We also briefly discuss the implications for the idea that T-duality and its generalizations should be thought of as discrete gauge symmetries in spacetime.

Spectral sum rules for confining large-N theories

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cherman, Aleksey; McGady, David A.; Yamazaki, Masahito

2016-06-17

We consider asymptotically-free four-dimensional large-$N$ gauge theories with massive fermionic and bosonic adjoint matter fields, compactified on squashed three-spheres, and examine their regularized large-$N$ confined-phase spectral sums. The analysis is done in the limit of vanishing ’t Hooft coupling, which is justified by taking the size of the compactification manifold to be small compared to the inverse strong scale Λ ₋1. We find our results motivate us to conjecture some universal spectral sum rules for these large $N$ gauge theories.

Superstring Compactification and Low Energy Phenomenology.

NASA Astrophysics Data System (ADS)

Mohapatra, Pramoda Kumar

We have presented some aspects of Superstring compactification from 10 to 4 dimensions and the effect of different types of compactification of the extra 6 dimensions on the low energy physics. We have reviewed the consequences of demanding the extra 6 dimensions to form a manifold as well as an N = 1 Supersymmetry at low energies. While doing this we have also highlighted some of the fundamental phenomenological problems like proton decay and neutrino mass and their possible solutions. The dissertation includes a description of the method of calculation of discrete symmetries and Yukawa couplings between different fermions and mirror fermions in these kinds of manifold compactification. The explicit calculations for one particular case with three fermion generations is presented. The reasons for the necessity of an intermediate scale of symmetry breaking (between Plank scale and the electro-weak scale) are explained and one particular scenerio of such symmetry breaking which preserves Supersymmetry is given. We have studied the effect of E _6 singlets on F-flatness and on the phenomenology. We have also reviewed the idea of compactification in a completely different way, i.e. not on a regular manifold but on a manifold with singularities called an orbifold. We have shown that with the so-called standard embedding, meaning identifying the gauge connection with the spin connection, needed for anomaly cancellation and modular invariance, only one model has a chance of being phenomenologically realistic. We have provided explicit tables of all the relevant quantum numbers of the fermions in the fundamental representation of the gauge group E _6 and showed that there are three possible ways of embedding electric charge in the generators of E _6. We have given the explicit form of the renormalization group equation for sin^2theta_{ rm W} and alpha_ {s} for the most usual chain of breaking E _6 down to SU(3)_ {c}otimes SU(2)_{L}otimes(1) _{Y}. The importance of the evolution of the coupling constant on the compactification is also stressed. We have analysed the successes and the limitations of Superstring theories and have mentioned the new frontiers in compactification.

On `light' fermions and proton stability in `big divisor' D3/ D7 large volume compactifications

NASA Astrophysics Data System (ADS)

Misra, Aalok; Shukla, Pramod

2011-06-01

Building on our earlier work (Misra and Shukla, Nucl. Phys. B 827:112, 2010; Phys. Lett. B 685:347-352, 2010), we show the possibility of generating "light" fermion mass scales of MeV-GeV range (possibly related to the first two generations of quarks/leptons) as well as eV (possibly related to first two generations of neutrinos) in type IIB string theory compactified on Swiss-Cheese orientifolds in the presence of a mobile space-time filling D3-brane restricted to (in principle) stacks of fluxed D7-branes wrapping the "big" divisor Σ B . This part of the paper is an expanded version of the latter half of Sect. 3 of a published short invited review (Misra, Mod. Phys. Lett. A 26:1, 2011) written by one of the authors [AM]. Further, we also show that there are no SUSY GUT-type dimension-five operators corresponding to proton decay, and we estimate the proton lifetime from a SUSY GUT-type four-fermion dimension-six operator to be 1061 years. Based on GLSM calculations in (Misra and Shukla, Nucl. Phys. B 827:112, 2010) for obtaining the geometric Kähler potential for the "big divisor," using further the Donaldson's algorithm, we also briefly discuss in the first of the two appendices the metric for the Swiss-Cheese Calabi-Yau used, which we obtain and which becomes Ricci flat in the large-volume limit.

Stability analysis of compactifications of D = 11 supergravity with SU(3) × SU(2) × U(1) symmetry

NASA Astrophysics Data System (ADS)

Page, Don N.; Pope, C. N.

1984-09-01

We show that the Mpqr Freund-Rubin compactification of eleven-dimensional supergravity is classically stable if and only if 7/2761/2 < -p/q- < 17/117(66)1/2. Permanent address: Blackett Laboratory, Imperial College, London SW7 2BZ, United Kingdom.

Towards large volume big divisor D3/D7 " μ-split supersymmetry" and Ricci-flat Swiss-cheese metrics, and dimension-six neutrino mass operators

NASA Astrophysics Data System (ADS)

Dhuria, Mansi; Misra, Aalok

2012-02-01

We show that it is possible to realize a " μ-split SUSY" scenario (Cheng and Cheng, 2005) [1] in the context of large volume limit of type IIB compactifications on Swiss-cheese Calabi-Yau orientifolds in the presence of a mobile space-time filling D3-brane and a (stack of) D7-brane(s) wrapping the "big" divisor. For this, we investigate the possibility of getting one Higgs to be light while other to be heavy in addition to a heavy higgsino mass parameter. Further, we examine the existence of long lived gluino that manifests one of the major consequences of μ-split SUSY scenario, by computing its decay width as well as lifetime corresponding to the three-body decays of the gluino into either a quark, a squark and a neutralino or a quark, squark and goldstino, as well as two-body decays of the gluino into either a neutralino and a gluon or a goldstino and a gluon. Guided by the geometric Kähler potential for Σ obtained in Misra and Shukla (2010) [2] based on GLSM techniques, and the Donaldson's algorithm (Barun et al., 2008) [3] for obtaining numerically a Ricci-flat metric, we give details of our calculation in Misra and Shukla (2011) [4] pertaining to our proposed metric for the full Swiss-cheese Calabi-Yau (the geometric Kähler potential being needed to be included in the full moduli space Kähler potential in the presence of the mobile space-time filling D3-brane), but for simplicity of calculation, close to the big divisor, which is Ricci-flat in the large volume limit. Also, as an application of the one-loop RG flow solution for the higgsino mass parameter, we show that the contribution to the neutrino masses at the EW scale from dimension-six operators arising from the Kähler potential, is suppressed relative to the Weinberg-type dimension-five operators.

Exploring the potential energy landscape over a large parameter-space

NASA Astrophysics Data System (ADS)

He, Yang-Hui; Mehta, Dhagash; Niemerg, Matthew; Rummel, Markus; Valeanu, Alexandru

2013-07-01

Solving large polynomial systems with coefficient parameters are ubiquitous and constitute an important class of problems. We demonstrate the computational power of two methods — a symbolic one called the Comprehensive Gröbner basis and a numerical one called coefficient-parameter polynomial continuation — applied to studying both potential energy landscapes and a variety of questions arising from geometry and phenomenology. Particular attention is paid to an example in flux compactification where important physical quantities such as the gravitino and moduli masses and the string coupling can be efficiently extracted.

Compactification on phase space

NASA Astrophysics Data System (ADS)

Lovelady, Benjamin; Wheeler, James

2016-03-01

A major challenge for string theory is to understand the dimensional reduction required for comparison with the standard model. We propose reducing the dimension of the compactification by interpreting some of the extra dimensions as the energy-momentum portion of a phase-space. Such models naturally arise as generalized quotients of the conformal group called biconformal spaces. By combining the standard Kaluza-Klein approach with such a conformal gauge theory, we may start from the conformal group of an n-dimensional Euclidean space to form a 2n-dimensional quotient manifold with symplectic structure. A pair of involutions leads naturally to two n-dimensional Lorentzian manifolds. For n = 5, this leaves only two extra dimensions, with a countable family of possible compactifications and an SO(5) Yang-Mills field on the fibers. Starting with n=6 leads to 4-dimensional compactification of the phase space. In the latter case, if the two dimensions each from spacetime and momentum space are compactified onto spheres, then there is an SU(2)xSU(2) (left-right symmetric electroweak) field between phase and configuration space and an SO(6) field on the fibers. Such a theory, with minor additional symmetry breaking, could contain all parts of the standard model.

Inflation from higher dimensions

NASA Astrophysics Data System (ADS)

Nakada, Hiroshi; Ketov, Sergei V.

2017-12-01

We derive the scalar potential in four spacetime dimensions from an eight-dimensional (R +γ R4-2 Λ -F42) gravity model in the presence of the 4-form F4, with the (modified gravity) coupling constant γ and the cosmological constant Λ , by using the flux compactification of four extra dimensions on a 4-sphere with the warp factor. The scalar potential depends upon two scalar fields: the scalaron and the 4-sphere volume modulus. We demonstrate that it gives rise to a viable description of cosmological inflation in the early universe, with the scalaron playing the role of inflaton and the volume modulus to be (almost) stabilized at its minimum. We also speculate about a possibility of embedding our model in eight dimensions into a modified eight-dimensional supergavity that, in its turn, arises from a modified eleven-dimensional supergravity.

Large dimensions and small curvatures from supersymmetric brane back-reaction

NASA Astrophysics Data System (ADS)

Burgess, C. P.; van Nierop, L.

2011-04-01

We compute the back-reaction of pairs of codimension-two branes within an explicit flux-stabilized compactification, to trace how its properties depend on the parameters that define the brane-bulk couplings. Both brane tension and magnetic couplings to the stabilizing flux play an important role in the resulting dynamics, with the magnetic coupling allowing some of the flux to be localized on the branes (thus changing the flux-quantization conditions). We find that back-reaction lifts the classical flat directions of the bulk supergravity, and we calculate both the scalar potential and changes to the extra-dimensional and on-brane geometries that result, as functions of the assumed brane couplings. When linearized about simple rugby-ball geometries the resulting solutions allow a systematic exploration of the system's response. Several of the systems we explore have remarkable properties. Among these are a propensity for the extra dimensions to stabilize at exponentially large sizes, providing a mechanism for generating extremely large volumes. In some circumstances the brane-dilaton coupling allows the bulk dilaton to adjust to suppress the on-brane curvature parametrically below the change in brane tension, potentially providing a mechanism for reducing the vacuum energy. We explore the stability of this suppression to quantum effects in the case where their strength is controlled by the value of the field along the classical flat direction, and find it can (but need not) be stable.

Limits on Large Extra Dimensions Based on Observations of Neutron Stars with the Fermi-LAT

NASA Technical Reports Server (NTRS)

Ferrara, E. C.; Scargle, J. D.; Troja, E.

2012-01-01

We present limits for the compactification scale in the theory of Large Extra Dimensions (LED) proposed by Arkani-Hamed, Dimopoulos, and Dvali. We use 11 months of data from the Fermi Large Area Telescope (Fermi-LAT) to set gamma ray flux limits for 6 gamma-ray faint neutron stars (NS). To set limits on LED we use the model of Hannestad and Raffelt (HR) that calculates the Kaluza-Klein (KK) graviton production in supernova cores and the large fraction subsequently gravitationally bound around the resulting NS. The predicted decay of the bound KK gravitons to should contribute to the flux from NSs. Considering 2 to 7 extra dimensions of the same size in the context of the HR model, we use Monte Carlo techniques to calculate the expected differential flux of gamma-rays arising from these KK gravitons, including the effects of the age of the NS, graviton orbit, and absorption of gamma-rays in the magnetosphere of the NS. We compare our Monte Carlo-based differential flux to the experimental differential flux using maximum likelihood techniques to obtain our limits on LED. Our limits are more restrictive than past EGRET-based optimistic limits that do not include these important corrections. Additionally, our limits are more stringent than LHC based limits for 3 or fewer LED, and comparable for 4 LED. We conclude that if the effective Planck scale is around a TeV, then for 2 or 3 LED the compactification topology must be more complicated than a torus.

Limits on Large Extra Dimensions Based on Observations of Neutron Stars with the Fermi-LAT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ajello, M.; /SLAC /KIPAC, Menlo Park; Baldini, L.

We present limits for the compactification scale in the theory of Large Extra Dimensions (LED) proposed by Arkani-Hamed, Dimopoulos, and Dvali. We use 11 months of data from the Fermi Large Area Telescope (Fermi-LAT) to set gamma ray flux limits for 6 gamma-ray faint neutron stars (NS). To set limits on LED we use the model of Hannestad and Raffelt (HR) that calculates the Kaluza-Klein (KK) graviton production in supernova cores and the large fraction subsequently gravitationally bound around the resulting NS. The predicted decay of the bound KK gravitons to {gamma}{gamma} should contribute to the flux from NSs. Consideringmore » 2 to 7 extra dimensions of the same size in the context of the HR model, we use Monte Carlo techniques to calculate the expected differential flux of gamma-rays arising from these KK gravitons, including the effects of the age of the NS, graviton orbit, and absorption of gamma-rays in the magnetosphere of the NS. We compare our Monte Carlo-based differential flux to the experimental differential flux using maximum likelihood techniques to obtain our limits on LED. Our limits are more restrictive than past EGRET-based optimistic limits that do not include these important corrections. Additionally, our limits are more stringent than LHC based limits for 3 or fewer LED, and comparable for 4 LED. We conclude that if the effective Planck scale is around a TeV, then for 2 or 3 LED the compactification topology must be more complicated than a torus.« less

Limits on large extra dimensions based on observations of neutron stars with the Fermi-LAT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ajello, M.; Bechtol, K.; Berenji, B.

We present limits for the compactification scale in the theory of Large Extra Dimensions (LED) proposed by Arkani-Hamed, Dimopoulos, and Dvali. We use 11 months of data from the Fermi Large Area Telescope (Fermi-LAT) to set gamma ray flux limits for 6 gamma-ray faint neutron stars (NS). To set limits on LED we use the model of Hannestad and Raffelt (HR) that calculates the Kaluza-Klein (KK) graviton production in supernova cores and the large fraction subsequently gravitationally bound around the resulting NS. The predicted decay of the bound KK gravitons to γγ should contribute to the flux from NSs. Consideringmore » 2 to 7 extra dimensions of the same size in the context of the HR model, we use Monte Carlo techniques to calculate the expected differential flux of gamma-rays arising from these KK gravitons, including the effects of the age of the NS, graviton orbit, and absorption of gamma-rays in the magnetosphere of the NS. We compare our Monte Carlo-based differential flux to the experimental differential flux using maximum likelihood techniques to obtain our limits on LED. Our limits are more restrictive than past EGRET-based optimistic limits that do not include these important corrections. Additionally, our limits are more stringent than LHC based limits for 3 or fewer LED, and comparable for 4 LED. We conclude that if the effective Planck scale is around a TeV, then for 2 or 3 LED the compactification topology must be more complicated than a torus.« less

Limits on large extra dimensions based on observations of neutron stars with the Fermi-LAT

DOE PAGES

Ajello, M.

2012-02-01

We present limits for the compactification scale in the theory of Large Extra Dimensions (LED) proposed by Arkani-Hamed, Dimopoulos, and Dvali. We use 11 months of data from the Fermi Large Area Telescope (Fermi-LAT) to set gamma ray flux limits for 6 gamma-ray faint neutron stars (NS). To set limits on LED we use the model of Hannestad and Raffelt (HR) that calculates the Kaluza-Klein (KK) graviton production in supernova cores and the large fraction subsequently gravitationally bound around the resulting NS. The predicted decay of the bound KK gravitons to γγ should contribute to the flux from NSs. Consideringmore » 2 to 7 extra dimensions of the same size in the context of the HR model, we use Monte Carlo techniques to calculate the expected differential flux of gamma-rays arising from these KK gravitons, including the effects of the age of the NS, graviton orbit, and absorption of gamma-rays in the magnetosphere of the NS. We compare our Monte Carlo-based differential flux to the experimental differential flux using maximum likelihood techniques to obtain our limits on LED. Our limits are more restrictive than past EGRET-based optimistic limits that do not include these important corrections. Additionally, our limits are more stringent than LHC based limits for 3 or fewer LED, and comparable for 4 LED. We conclude that if the effective Planck scale is around a TeV, then for 2 or 3 LED the compactification topology must be more complicated than a torus.« less

The Casimir effect in rugby-ball type flux compactifications

NASA Astrophysics Data System (ADS)

Minamitsuji, M.

2008-04-01

We discuss volume stabilization in a 6D braneworld model based on 6D supergravity theory. The internal space is compactified by magnetic flux and contains codimension two 3-branes (conical singularities) as its boundaries. In general the external 4D spacetime is warped and in the unwrapped limit the shape of the internal space looks like a 'rugby ball'. The size of the internal space is not fixed due to the scale invariance of the supergravity theory. We discuss the possibility of volume stabilization by the Casimir effect for a massless, minimally coupled bulk scalar field. The main obstacle in studying this case is that the brane (conical) part of the relevant heat kernel coefficient (a6) has not been formulated. Thus as a first step, we consider the 4D analog model with boundary codimension two 1-branes. The spacetime structure of the 4D model is very similar to that of the original 6D model, where now the relevant heat kernel coefficient is well known. We derive the one-loop effective potential induced by a scalar field in the bulk by employing zeta function regularization with heat kernel analysis. As a result, the volume is stabilized for most possible choices of the parameters. Especially, for a larger degree of warping, our results imply that a large hierarchy between the mass scales and a tiny amount of effective cosmological constant can be realized on the brane. In the non-warped limit the ratio tends to converge to the same value, independently of the bulk gauge coupling constant. Finally, we will analyze volume stabilization in the original model 6D by employing the same mode-sum technique.

Matter field Kähler metric in heterotic string theory from localisation

NASA Astrophysics Data System (ADS)

Blesneag, Ştefan; Buchbinder, Evgeny I.; Constantin, Andrei; Lukas, Andre; Palti, Eran

2018-04-01

We propose an analytic method to calculate the matter field Kähler metric in heterotic compactifications on smooth Calabi-Yau three-folds with Abelian internal gauge fields. The matter field Kähler metric determines the normalisations of the N = 1 chiral superfields, which enter the computation of the physical Yukawa couplings. We first derive the general formula for this Kähler metric by a dimensional reduction of the relevant supergravity theory and find that its T-moduli dependence can be determined in general. It turns out that, due to large internal gauge flux, the remaining integrals localise around certain points on the compactification manifold and can, hence, be calculated approximately without precise knowledge of the Ricci-flat Calabi-Yau metric. In a final step, we show how this local result can be expressed in terms of the global moduli of the Calabi-Yau manifold. The method is illustrated for the family of Calabi-Yau hypersurfaces embedded in P^1× P^3 and we obtain an explicit result for the matter field Kähler metric in this case.

Stabilizing all geometric moduli in heterotic Calabi-Yau vacua

DOE PAGES

Anderson, Lara B.; Gray, James; Lukas, Andre; ...

2011-05-27

We propose a scenario to stabilize all geometric moduli - that is, the complex structure, Kähler moduli and the dilaton - in smooth heterotic Calabi-Yau compactifications without Neveu-Schwarz three-form flux. This is accomplished using the gauge bundle required in any heterotic compactification, whose perturbative effects on the moduli are combined with non-perturbative corrections. We argue that, for appropriate gauge bundles, all complex structure and a large number of other moduli can be perturbatively stabilized - in the most restrictive case, leaving only one combination of Kähler moduli and the dilaton as a flat direction. At this stage, the remaining modulimore » space consists of Minkowski vacua. That is, the perturbative superpotential vanishes in the vacuum without the necessity to fine-tune flux. Finally, we incorporate non-perturbative effects such as gaugino condensation and/or instantons. These are strongly constrained by the anomalous U(1) symmetries which arise from the required bundle constructions. We present a specific example, with a consistent choice of non-perturbative effects, where all remaining flat directions are stabilized in an AdS vacuum.« less

Revisiting arithmetic solutions to the W =0 condition

NASA Astrophysics Data System (ADS)

Kanno, Keita; Watari, Taizan

2017-11-01

The gravitino mass is expected not to be much smaller than the Planck scale for a large fraction of vacua in flux compactifications. There is no continuous parameter to tune even by hand, and it seems that the gravitino mass can be small only as a result of accidental cancellation among period integrals weighted by integer-valued flux quanta. DeWolfe et al. [J. High Energy Phys. 02 (2005) 037, 10.1088/1126-6708/2005/02/037] proposed paying close attention to vacua where the Hodge decomposition is possible within a number field, so that the precise cancellation takes place as a result of algebra. We focus on a subclass of those vacua—those with complex multiplication—and explore more on the idea in this article. It turns out, in Type IIB compactifications, that those vacua admit nontrivial supersymmetric flux configurations if and only if the reflex field of the Weil intermediate Jacobian is isomorphic to the quadratic imaginary field generated by the axidilaton vacuum expectation value. We also found that flux statistics are highly enriched on such vacua, as F-term conditions become linearly dependent.

Ubiquity of non-geometry in heterotic compactifications

DOE PAGES

García-Etxebarria, Iñaki; Lüst, Dieter; Massai, Stefano; ...

2017-03-08

Here, we study the effect of quantum corrections on heterotic compactifications on elliptic fibrations away from the stable degeneration limit, elaborating on a recent observation by Malmendier and Morrison. We show that already for the simplest nontrivial elliptic fibration the effect is quite dramatic: the I 1 degeneration with trivial gauge background dynamically splits into two T-fects with monodromy around each T-fect being (conjugate to) T-duality along one of the legs of the T 2. This implies that almost every elliptic heterotic compactification becomes a non-geometric T-fold away from the stable degeneration limit. We also point out a subtlety duemore » to this non-geometric splitting at finite fiber size. It arises when determining, via heterotic/F-theory duality, the SCFTs associated to a small number of pointlike instantons probing heterotic ADE singularities. Along the way we resolve various puzzles in the literature.« less

Supersymmetry: Compactification, flavor, and dualities

NASA Astrophysics Data System (ADS)

Heidenreich, Benjamin Jones

We describe several new research directions in the area of supersymmetry. In the context of low-energy supersymmetry, we show that the assumption of R-parity can be replaced with the minimal flavor violation hypothesis, solving the issue of nucleon decay and the new physics flavor problem in one stroke. The assumption of minimal flavor violation uniquely fixes the form of the baryon number violating vertex, leading to testable predictions. The NLSP is unstable, and decays promptly to jets, evading stringent bounds on vanilla supersymmetry from LHC searches, whereas the gravitino is long-lived, and can be a dark matter component. In the case of a sbottom LSP, neutral mesinos can form and undergo oscillations before decaying, leading to same sign tops, and allowing us to place constraints on the model in this case. We show that this well-motivated phenomenology can be naturally explained by spontaneously breaking a gauged flavor symmetry at a high scale in the presence of additional vector-like quarks, leading to mass mixings which simultaneously generate the flavor structure of the baryon-number violating vertex and the Standard Model Yukawa couplings, explaining their minimal flavor violating structure. We construct a model which is robust against Planck suppressed corrections and which also solves the mu problem. In the context of flux compactifications, we begin a study of the local geometry near a stack of D7 branes supporting a gaugino condensate, an integral component of the KKLT scenario for Kahler moduli stabilization. We obtain an exact solution for the geometry in a certain limit using reasonable assumptions about symmetries, and argue that this solution exhibits BPS domain walls, as expected from field theory arguments. We also begin a larger program of understanding general supersymmetric compactifications of type IIB string theory, reformulating previous results in an SL(2, R ) covariant fashion. Finally, we present extensive evidence for a new class of N = 1 gauge theory dualities relating different world-volume gauge theories of D3 branes probing an orientifold singularity. We argue that these dualities originate from the S-duality of type IIB string theory, much like electromagnetic dualities of N = 4 gauge theories.

Tinkertoys for the E 7 theory

NASA Astrophysics Data System (ADS)

Chacaltana, Oscar; Distler, Jacques; Trimm, Anderson; Zhu, Yinan

2018-05-01

We classify the class S theories of type E 7. These are four-dimensional N=2 superconformal field theories arising from the compactification of the E 7 (2, 0) theory on a punctured Riemann surface, C. The classification is given by listing all 3-punctured spheres ("fixtures"), and connecting cylinders, which can arise in a pants-decomposition of C. We find exactly 11,000 fixtures with three regular punctures, and an additional 48 with one "irregular puncture" (in the sense used in our previous works). To organize this large number of theories, we have created a web application at https://golem.ph.utexas.edu/class-S/E7/. Among these theories, we find 10 new ones with a simple exceptional global symmetry group, as well as a new rank-2 SCFT and several new rank-3 SCFTs. As an application, we study the strong-coupling limit of the E 7 gauge theory with 3 hypermultiplets in the 56. Using our results, we also verify recent conjectures that the T 2 compactification of certain 6 d (1, 0) theories can alternatively be realized in class S as fixtures in the E 7 or E 8 theories.

Abelian gauge symmetries in F-theory and dual theories

NASA Astrophysics Data System (ADS)

Song, Peng

In this dissertation, we focus on important physical and mathematical aspects, especially abelian gauge symmetries, of F-theory compactifications and its dual formulations within type IIB and heterotic string theory. F-theory is a non-perturbative formulation of type IIB string theory which enjoys important dualities with other string theories such as M-theory and E8 x E8 heterotic string theory. One of the main strengths of F-theory is its geometrization of many physical problems in the dual string theories. In particular, its study requires a lot of mathematical tools such as advanced techniques in algebraic geometry. Thus, it has also received a lot of interests among mathematicians, and is a vivid area of research within both the physics and the mathematics community. Although F-theory has been a long-standing theory, abelian gauge symmetry in Ftheory has been rarely studied, until recently. Within the mathematics community, in 2009, Grassi and Perduca first discovered the possibility of constructing elliptically fibered varieties with non-trivial toric Mordell-Weil group. In the physics community, in 2012, Morrison and Park first made a major advancement by constructing general F-theory compactifications with U(1) abelian gauge symmetry. They found that in such cases, the elliptically-fibered Calabi-Yau manifold that F-theory needs to be compactified on has its fiber being a generic elliptic curve in the blow-up of the weighted projective space P(1;1;2) at one point. Subsequent developments have been made by Cvetic, Klevers and Piragua extended the works of Morrison and Park and constructed general F-theory compactifications with U(1) x U(1) abelian gauge symmetry. They found that in the U(1) x U(1) abelian gauge symmetry case, the elliptically-fibered Calabi-Yau manifold that F-theory needs to be compactified on has its fiber being a generic elliptic curve in the del Pezzo surface dP2. In chapter 2 of this dissertation, I bring this a step further by constructing general F-theory compactifications with U(1) x U(1) x U(1) abelian gauge symmetry. In chapter 1 of this dissertation, I proved finiteness of a region of the string landscape in Type IIB compactifications. String compactifications give rise to a collection of effective low energy theories, known as the string landscape. In chapter 3 of this dissertation, I study abelian gauge symmetries in the duality between F-theory and E8 x E8 heterotic string theory. However, how abelian gauge symmetries can arise in the dual heterotic string theory has never been studied. The main goal of this chapter is to study exactly this. We start with F-theory compactifications with abelian gauge symmetry. With the help of a mathematical lemma as well as a computer code that I came up with, I was able to construct a rich list of specialized examples with specific abelian and nonabelian gauge groups on the F-theory side. (Abstract shortened by ProQuest.).

Bulk renormalization and particle spectrum in codimension-two brane worlds

NASA Astrophysics Data System (ADS)

Salvio, Alberto

2013-04-01

We study the Casimir energy due to bulk loops of matter fields in codimension-two brane worlds and discuss how effective field theory methods allow us to use this result to renormalize the bulk and brane operators. In the calculation we explicitly sum over the Kaluza-Klein (KK) states with a new convenient method, which is based on a combined use of zeta function and dimensional regularization. Among the general class of models we consider we include a supersymmetric example, 6D gauged chiral supergravity. Although much of our discussion is more general, we treat in some detail a class of compactifications, where the extra dimensions parametrize a rugby ball shaped space with size stabilized by a bulk magnetic flux. The rugby ball geometry requires two branes, which can host the Standard Model fields and carry both tension and magnetic flux (of the bulk gauge field), the leading terms in a derivative expansion. The brane properties have an impact on the KK spectrum and therefore on the Casimir energy as well as on the renormalization of the brane operators. A very interesting feature is that when the two branes carry exactly the same amount of flux, one half of the bulk supersymmetries survives after the compactification, even if the brane tensions are large. We also discuss the implications of these calculations for the natural value of the cosmological constant when the bulk has two large extra dimensions and the bulk supersymmetry is partially preserved (or completely broken).

Numerical exploration of the string theory landscape

NASA Astrophysics Data System (ADS)

Metallinos, Konstantinos

String theory is the best candidate to provide a consistent quantum theory of gravity. Its ten dimensional formulation forces us to perform a compactification of the six unobserved dimensions in a very special compact manifold known as Calabi-Yau. The standard way to address this issue is through the flux compactification scenarios. One of the major implications of these scenarios is that the string theory cannot provide a single and unique vacuum as a solution. Rather one can find an extremely large set of solutions, each with its own physical properties. This is the string theory Landscape. In the first part we present the formal description of the flux compactification theory. From the four dimensional point of view this is a supersymmetric theory, fully described only by two functions, the superpotential and the Kahler potential. Their expressions are crucially depend on the geometrical properties of the compact manifold. By writing these functions for the specific Calabi-Yau manifold P41,1,1,6,9 we are looking firstly for supersymmetric and then after breaking the supersymmetry, for non-supersymmetric numerical solutions. These solutions describe the possible vacua and our goal is using statistical analysis to categorize them based on their cosmological properties and to check their stability. Finally we present the existence of stable dS vacua with and without adding an uplifting term on the potential. In the case where there is not an uplifting term the breaking of supersymmetry is done by incorporating alpha' corrections to the Kahler potential. In the second part we construct a KKLT like inflation model, within string theory flux compactifications and, in particular a model of accidental inflation. We investigate the possibility that the apparent fine-tuning of the low energy parameters of the theory needed to have inflation can be generically obtained by scanning the values of the fluxes over the landscape. Furthermore, we find that the existence of a landscape of eternal inflation in this model provides us with a natural theory of initial conditions for the inflationary period in our vacuum. We demonstrate how these two effects work in a small corner of the landscape associated with the complex structure of the Calabi-Yau manifold P41,1,1,6,9 by numerically investigating the flux vacua of a reduced moduli space. This allows us to obtain the distribution of observable parameters for inflation in this mini-landscape directly from the fluxes.

Forbidden territories in the string landscape

NASA Astrophysics Data System (ADS)

Kumar, Alok; Mukhopadhyay, Subir; Ray, Koushik

2007-12-01

Problems of stabilizing moduli of the type-IIB string theory on toroidal orientifolds T6/Z2, in presence of worldvolume fluxes on various D-branes, are considered. For Z2 actions, introducing either O9 or O3 planes, we rule out the possibility of moduli stabilization in a wide class of models with Script N = 1 supersymmetry, characterized by the type of fluxes turned on along D-brane worldvolume. Our results, in particular, imply that Abelian worldvolume fluxes can not by themselves stabilize closed string moduli, in a consistent supersymmtric model, for above orientifold compactifications. We also discuss other Z2 orientifolds of T6 and show that certain other brane wrappings are also ruled out by similar consistency requirements. In specific setups we consider examples with D9-branes wrapping on a complex three-torus with its world-volume fluxes taken to be semi-homogeneous bundles and D7-branes wrapping holomorphic four-cycles of the complex three-torus carrying world-volume fluxes.

Tops as building blocks for G 2 manifolds

NASA Astrophysics Data System (ADS)

Braun, Andreas P.

2017-10-01

A large number of examples of compact G 2 manifolds, relevant to supersymmetric compactifications of M-Theory to four dimensions, can be constructed by forming a twisted connected sum of two building blocks times a circle. These building blocks, which are appropriate K3-fibred threefolds, are shown to have a natural and elegant construction in terms of tops, which parallels the construction of Calabi-Yau manifolds via reflexive polytopes. In particular, this enables us to prove combinatorial formulas for the Hodge numbers and other relevant topological data.

Tensor modes on the string theory landscape

NASA Astrophysics Data System (ADS)

Westphal, Alexander

2013-04-01

We attempt an estimate for the distribution of the tensor mode fraction r over the landscape of vacua in string theory. The dynamics of eternal inflation and quantum tunneling lead to a kind of democracy on the landscape, providing no bias towards large-field or small-field inflation regardless of the class of measure. The tensor mode fraction then follows the number frequency distributions of inflationary mechanisms of string theory over the landscape. We show that an estimate of the relative number frequencies for small-field vs large-field inflation, while unattainable on the whole landscape, may be within reach as a regional answer for warped Calabi-Yau flux compactifications of type IIB string theory.

Gauged supergravities from M-theory reductions

NASA Astrophysics Data System (ADS)

Katmadas, Stefanos; Tomasiello, Alessandro

2018-04-01

In supergravity compactifications, there is in general no clear prescription on how to select a finite-dimensional family of metrics on the internal space, and a family of forms on which to expand the various potentials, such that the lower-dimensional effective theory is supersymmetric. We propose a finite-dimensional family of deformations for regular Sasaki-Einstein seven-manifolds M 7, relevant for M-theory compactifications down to four dimensions. It consists of integrable Cauchy-Riemann structures, corresponding to complex deformations of the Calabi-Yau cone M 8 over M 7. The non-harmonic forms we propose are the ones contained in one of the Kohn-Rossi cohomology groups, which is finite-dimensional and naturally controls the deformations of Cauchy-Riemann structures. The same family of deformations can be also described in terms of twisted cohomology of the base M 6, or in terms of Milnor cycles arising in deformations of M 8. Using existing results on SU(3) structure compactifications, we briefly discuss the reduction of M-theory on our class of deformed Sasaki-Einstein manifolds to four-dimensional gauged supergravity.

F-theory models on K3 surfaces with various Mordell-Weil ranks — constructions that use quadratic base change of rational elliptic surfaces

NASA Astrophysics Data System (ADS)

Kimura, Yusuke

2018-05-01

We constructed several families of elliptic K3 surfaces with Mordell-Weil groups of ranks from 1 to 4. We studied F-theory compactifications on these elliptic K3 surfaces times a K3 surface. Gluing pairs of identical rational elliptic surfaces with nonzero Mordell-Weil ranks yields elliptic K3 surfaces, the Mordell-Weil groups of which have nonzero ranks. The sum of the ranks of the singularity type and the Mordell-Weil group of any rational elliptic surface with a global section is 8. By utilizing this property, families of rational elliptic surfaces with various nonzero Mordell-Weil ranks can be obtained by choosing appropriate singularity types. Gluing pairs of these rational elliptic surfaces yields families of elliptic K3 surfaces with various nonzero Mordell-Weil ranks. We also determined the global structures of the gauge groups that arise in F-theory compactifications on the resulting K3 surfaces times a K3 surface. U(1) gauge fields arise in these compactifications.

Qubit and fermionic Fock spaces from type II superstring black holes

NASA Astrophysics Data System (ADS)

Belhaj, A.; Bensed, M.; Benslimane, Z.; Sedra, M. B.; Segui, A.

Using Hodge diagram combinatorial data, we study qubit and fermionic Fock spaces from the point of view of type II superstring black holes based on complex compactifications. Concretely, we establish a one-to-one correspondence between qubits, fermionic spaces and extremal black holes in maximally supersymmetric supergravity obtained from type II superstring on complex toroidal and Calabi-Yau compactifications. We interpret the differential forms of the n-dimensional complex toroidal compactification as states of n-qubits encoding information on extremal black hole charges. We show that there are 2n copies of n qubit systems which can be split as 2n = 2n-1 + 2n-1. More precisely, 2n-1 copies are associated with even D-brane charges in type IIA superstring and the other 2n-1 ones correspond to odd D-brane charges in IIB superstring. This correspondence is generalized to a class of Calabi-Yau manifolds. In connection with black hole charges in type IIA superstring, an n-qubit system has been obtained from a canonical line bundle of n factors of one-dimensional projective space ℂℙ1.

Compactified cosmological simulations of the infinite universe

NASA Astrophysics Data System (ADS)

Rácz, Gábor; Szapudi, István; Csabai, István; Dobos, László

2018-06-01

We present a novel N-body simulation method that compactifies the infinite spatial extent of the Universe into a finite sphere with isotropic boundary conditions to follow the evolution of the large-scale structure. Our approach eliminates the need for periodic boundary conditions, a mere numerical convenience which is not supported by observation and which modifies the law of force on large scales in an unrealistic fashion. We demonstrate that our method outclasses standard simulations executed on workstation-scale hardware in dynamic range, it is balanced in following a comparable number of high and low k modes and, its fundamental geometry and topology match observations. Our approach is also capable of simulating an expanding, infinite universe in static coordinates with Newtonian dynamics. The price of these achievements is that most of the simulated volume has smoothly varying mass and spatial resolution, an approximation that carries different systematics than periodic simulations. Our initial implementation of the method is called StePS which stands for Stereographically projected cosmological simulations. It uses stereographic projection for space compactification and naive O(N^2) force calculation which is nevertheless faster to arrive at a correlation function of the same quality than any standard (tree or P3M) algorithm with similar spatial and mass resolution. The N2 force calculation is easy to adapt to modern graphics cards, hence our code can function as a high-speed prediction tool for modern large-scale surveys. To learn about the limits of the respective methods, we compare StePS with GADGET-2 running matching initial conditions.

StePS: Stereographically Projected Cosmological Simulations

NASA Astrophysics Data System (ADS)

Rácz, Gábor; Szapudi, István; Csabai, István; Dobos, László

2018-05-01

StePS (Stereographically Projected Cosmological Simulations) compactifies the infinite spatial extent of the Universe into a finite sphere with isotropic boundary conditions to simulate the evolution of the large-scale structure. This eliminates the need for periodic boundary conditions, which are a numerical convenience unsupported by observation and which modifies the law of force on large scales in an unrealistic fashion. StePS uses stereographic projection for space compactification and naive O(N2) force calculation; this arrives at a correlation function of the same quality more quickly than standard (tree or P3M) algorithms with similar spatial and mass resolution. The N2 force calculation is easy to adapt to modern graphics cards, hence StePS can function as a high-speed prediction tool for modern large-scale surveys.

The orbifolder: A tool to study the low-energy effective theory of heterotic orbifolds

NASA Astrophysics Data System (ADS)

Nilles, H. P.; Ramos-Sánchez, S.; Vaudrevange, P. K. S.; Wingerter, A.

2012-06-01

The orbifolder is a program developed in C++ that computes and analyzes the low-energy effective theory of heterotic orbifold compactifications. The program includes routines to compute the massless spectrum, to identify the allowed couplings in the superpotential, to automatically generate large sets of orbifold models, to identify phenomenologically interesting models (e.g. MSSM-like models) and to analyze their vacuum configurations. Program summaryProgram title: orbifolder Catalogue identifier: AELR_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AELR_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: GNU General Public License version 3 No. of lines in distributed program, including test data, etc.: 145 572 No. of bytes in distributed program, including test data, etc.: 930 517 Distribution format: tar.gz Programming language:C++ Computer: Personal computer Operating system: Tested on Linux (Fedora 15, Ubuntu 11, SuSE 11) Word size: 32 bits or 64 bits Classification: 11.1 External routines: Boost (http://www.boost.org/), GSL (http://www.gnu.org/software/gsl/) Nature of problem: Calculating the low-energy spectrum of heterotic orbifold compactifications. Solution method: Quadratic equations on a lattice; representation theory; polynomial algebra. Running time: Less than a second per model.

125 GeV Higgs boson mass from 5D gauge-Higgs unification

NASA Astrophysics Data System (ADS)

Carson, Jason; Okada, Nobuchika

2018-03-01

In the context of a simple gauge-Higgs unification (GHU) scenario based on the gauge group SU(3)×U(1)^' in a 5D flat space-time, we investigate the possibility of reproducing the observed Higgs boson mass of around 125 GeV. We introduce bulk fermion multiplets with a bulk mass and a (half-)periodic boundary condition. In our analysis, we adopt a low-energy effective theoretical approach of the GHU scenario, where the running Higgs quartic coupling is required to vanish at the compactification scale. Under this "gauge-Higgs condition," we investigate the renormalization group evolution of the Higgs quartic coupling and find a relation between the bulk mass and the compactification scale so as to reproduce the 125 GeV Higgs boson mass. Through quantum corrections at the one-loop level, the bulk fermions contribute to the Higgs boson production and decay processes and deviate the Higgs boson signal strengths at the Large Hadron Collider experiments from the Standard Model (SM) predictions. Employing the current experimental data that show that the Higgs boson signal strengths for a variety of Higgs decay modes are consistent with the SM predictions, we obtain lower mass bounds on the lightest mode of the bulk fermions to be around 1 TeV.

1+1 dimensional compactifications of string theory.

PubMed

Goheer, Naureen; Kleban, Matthew; Susskind, Leonard

2004-05-14

We argue that stable, maximally symmetric compactifications of string theory to 1+1 dimensions are in conflict with holography. In particular, the finite horizon entropies of the Rindler wedge in 1+1 dimensional Minkowski and anti-de Sitter space, and of the de Sitter horizon in any dimension, are inconsistent with the symmetries of these spaces. The argument parallels one made recently by the same authors, in which we demonstrated the incompatibility of the finiteness of the entropy and the symmetries of de Sitter space in any dimension. If the horizon entropy is either infinite or zero, the conflict is resolved.

Path integral formulation of the Hodge duality on the brane

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hahn, Sang-Ok; Kiem, Youngjai; Kim, Yoonbai

In the warped compactification with a single Randall-Sundrum brane, a puzzling claim has been made that scalar fields can be bound to the brane but their Hodge dual higher-rank antisymmetric tensors cannot. By explicitly requiring the Hodge duality, a prescription to resolve this puzzle was recently proposed by Duff and Liu. In this Brief Report, we implement the Hodge duality via the path integral formulation in the presence of the background gravity fields of warped compactifications. It is shown that the prescription of Duff and Liu can be naturally understood within this framework.

Matter-antimatter asymmetry in the universe via string-inspired CPT violation at early eras

NASA Astrophysics Data System (ADS)

Mavromatos, Nick E.

2018-01-01

In four-space-time dimensional string/brane theory, obtained either through compactification of the extra spatial dimensions, or by appropriate restriction to brane worlds with three large spatial dimensions, the rich physics potential associated with the presence of non-trivial Kalb-Ramond (KR) axion-like fields has not been fully exploited so far. In this talk, I discuss a scenario whereby such fields produce spontaneous Lorentz- and CPT-violating cosmological backgrounds over which strings propagate, which in the early Universe can lead to Baryogenesis through Leptogenesis in models with heavy right-handed neutrinos.

On the elliptic genera of manifolds of Spin(7) holonomy

DOE PAGES

Benjamin, Nathan; Harrison, Sarah M.; Kachru, Shamit; ...

2015-12-16

Superstring compactification on a manifold of Spin(7) holonomy gives rise to a 2d worldsheet conformal field theory with an extended supersymmetry algebra. The N=1 superconformal algebra is extended by additional generators of spins 2 and 5/2, and instead of just superconformal symmetry one has a c = 12 realization of the symmetry group SW(3/2,2). In this paper, we compute the characters of this supergroup and decompose the elliptic genus of a general Spin(7) compactification in terms of these characters. Here, we find suggestive relations to various sporadic groups, which are made more precise in a companion paper.

BPS equations and non-trivial compactifications

NASA Astrophysics Data System (ADS)

Tyukov, Alexander; Warner, Nicholas P.

2018-05-01

We consider the problem of finding exact, eleven-dimensional, BPS supergravity solutions in which the compactification involves a non-trivial Calabi-Yau manifold, Y , as opposed to simply a T 6. Since there are no explicitly-known metrics on non-trivial, compact Calabi-Yau manifolds, we use a non-compact "local model" and take the compactification manifold to be Y={M}_{GH}× {T}^2 , where ℳGH is a hyper-Kähler, Gibbons-Hawking ALE space. We focus on backgrounds with three electric charges in five dimensions and find exact families of solutions to the BPS equations that have the same four supersymmetries as the three-charge black hole. Our exact solution to the BPS system requires that the Calabi-Yau manifold be fibered over the space-time using compensators on Y . The role of the compensators is to ensure smoothness of the eleven-dimensional metric when the moduli of Y depend on the space-time. The Maxwell field Ansatz also implicitly involves the compensators through the frames of the fibration. We examine the equations of motion and discuss the brane distributions on generic internal manifolds that do not have enough symmetry to allow smearing.

Probing the string winding sector

NASA Astrophysics Data System (ADS)

Aldazabal, Gerardo; Mayo, Martín; Nuñez, Carmen

2017-03-01

We probe a slice of the massive winding sector of bosonic string theory from toroidal compactifications of Double Field Theory (DFT). This string subsector corresponds to states containing one left and one right moving oscillators. We perform a generalized Kaluza Klein compactification of DFT on generic 2 n-dimensional toroidal constant backgrounds and show that, up to third order in fluctuations, the theory coincides with the corresponding effective theory of the bosonic string compactified on n-dimensional toroidal constant backgrounds, obtained from three-point amplitudes. The comparison between both theories is facilitated by noticing that generalized diffeomorphisms in DFT allow to fix generalized harmonic gauge conditions that help in identifying the physical degrees of freedom. These conditions manifest as conformal anomaly cancellation requirements on the string theory side. The explicit expression for the gauge invariant effective action containing the physical massless sector (gravity+antisymmetric+gauge+ scalar fields) coupled to towers of generalized Kaluza Klein massive states (corresponding to compact momentum and winding modes) is found. The action acquires a very compact form when written in terms of fields carrying O( n, n) indices, and is explicitly T-duality invariant. The global algebra associated to the generalized Kaluza Klein compactification is discussed.

Hierarchies in Quantum Gravity: Large Numbers, Small Numbers, and Axions

NASA Astrophysics Data System (ADS)

Stout, John Eldon

Our knowledge of the physical world is mediated by relatively simple, effective descriptions of complex processes. By their very nature, these effective theories obscure any phenomena outside their finite range of validity, discarding information crucial to understanding the full, quantum gravitational theory. However, we may gain enormous insight into the full theory by understanding how effective theories with extreme characteristics--for example, those which realize large-field inflation or have disparate hierarchies of scales--can be naturally realized in consistent theories of quantum gravity. The work in this dissertation focuses on understanding the quantum gravitational constraints on these "extreme" theories in well-controlled corners of string theory. Axion monodromy provides one mechanism for realizing large-field inflation in quantum gravity. These models spontaneously break an axion's discrete shift symmetry and, assuming that the corrections induced by this breaking remain small throughout the excursion, create a long, quasi-flat direction in field space. This weakly-broken shift symmetry has been used to construct a dynamical solution to the Higgs hierarchy problem, dubbed the "relaxion." We study this relaxion mechanism and show that--without major modifications--it can not be naturally embedded within string theory. In particular, we find corrections to the relaxion potential--due to the ten-dimensional backreaction of monodromy charge--that conflict with naive notions of technical naturalness and render the mechanism ineffective. The super-Planckian field displacements necessary for large-field inflation may also be realized via the collective motion of many aligned axions. However, it is not clear that string theory provides the structures necessary for this to occur. We search for these structures by explicitly constructing the leading order potential for C4 axions and computing the maximum possible field displacement in all compactifications of type IIB string theory on toric Calabi-Yau hypersurfaces with h1,1 ≤ 4 in the Kreuzer-Skarke database. While none of these examples can sustain a super-Planckian displacement--the largest possible is 0.3 Mpl--we find an alignment mechanism responsible for large displacements in random matrix models at large h 1,1 >> 1, indicating that large-field inflation may be feasible in compactifications with tens or hundreds of axions. These results represent a modest step toward a complete understanding of large hierarchies and naturalness in quantum gravity.

Can compactifications solve the cosmological constant problem?

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hertzberg, Mark P.; Center for Theoretical Physics, Department of Physics,Massachusetts Institute of Technology,77 Massachusetts Ave, Cambridge, MA 02139; Masoumi, Ali

2016-06-30

Recently, there have been claims in the literature that the cosmological constant problem can be dynamically solved by specific compactifications of gravity from higher-dimensional toy models. These models have the novel feature that in the four-dimensional theory, the cosmological constant Λ is much smaller than the Planck density and in fact accumulates at Λ=0. Here we show that while these are very interesting models, they do not properly address the real cosmological constant problem. As we explain, the real problem is not simply to obtain Λ that is small in Planck units in a toy model, but to explain whymore » Λ is much smaller than other mass scales (and combinations of scales) in the theory. Instead, in these toy models, all other particle mass scales have been either removed or sent to zero, thus ignoring the real problem. To this end, we provide a general argument that the included moduli masses are generically of order Hubble, so sending them to zero trivially sends the cosmological constant to zero. We also show that the fundamental Planck mass is being sent to zero, and so the central problem is trivially avoided by removing high energy physics altogether. On the other hand, by including various large mass scales from particle physics with a high fundamental Planck mass, one is faced with a real problem, whose only known solution involves accidental cancellations in a landscape.« less

An exact elliptic superpotential for N=1 ∗ deformations of finite N=2 gauge theories

NASA Astrophysics Data System (ADS)

Dorey, Nick; Hollowood, Timothy J.; Kumar, S. Prem

2002-03-01

We study relevant deformations of the N=2 superconformal theory on the world-volume of N D3-branes at an Ak-1 singularity. In particular, we determine the vacuum structure of the mass-deformed theory with N=1 supersymmetry and show how the different vacua are permuted by an extended duality symmetry. We then obtain exact, modular covariant formulae (for all k, N and arbitrary gauge couplings) for the holomorphic observables in the massive vacua in two different ways: by lifting to M-theory, and by compactification to three dimensions and subsequent use of mirror symmetry. In the latter case, we find an exact superpotential for the model which coincides with a certain combination of the quadratic Hamiltonians of the spin generalization of the elliptic Calogero-Moser integrable system.

Wrapping rules (in) string theory

NASA Astrophysics Data System (ADS)

Bergshoeff, Eric A.; Riccioni, Fabio

2018-01-01

In this paper we show that the number of all 1/2-BPS branes in string theory compactified on a torus can be derived by universal wrapping rules whose formulation we present. These rules even apply to branes in less than ten dimensions whose ten-dimensional origin is an exotic brane. In that case the wrapping rules contain an additional combinatorial factor that is related to the highest dimension in which the ten-dimensional exotic brane, after compactification, can be realized as a standard brane. We show that the wrapping rules also apply to cases with less supersymmetry. As a specific example, we discuss the compactification of IIA/IIB string theory on ( T 4/ ℤ 2) × T n .

AdS-phobia, the WGC, the Standard Model and Supersymmetry

NASA Astrophysics Data System (ADS)

Gonzalo, Eduardo; Herráez, Alvaro; Ibáñez, Luis E.

2018-06-01

It has been recently argued that an embedding of the SM into a consistent theory of quantum gravity may imply important constraints on the mass of the lightest neutrino and the cosmological constant Λ4. The constraints come from imposing the absence of any non-SUSY AdS stable vacua obtained from any consistent compactification of the SM to 3 or 2 dimensions. This condition comes as a corollary of a recent extension of the Weak Gravity Conjecture (WGC) by Ooguri and Vafa. In this paper we study T 2 /Z N compactifications of the SM to two dimensions in which SM Wilson lines are projected out, leading to a considerable simplification. We analyze in detail a T 2 /Z 4 compactification of the SM in which both complex structure and Wilson line scalars are fixed and the potential is only a function of the area of the torus a 2. We find that the SM is not robust against the appearance of AdS vacua in 2D and hence would be by itself inconsistent with quantum gravity. On the contrary, if the SM is embedded at some scale M SS into a SUSY version like the MSSM, the AdS vacua present in the non-SUSY case disappear or become unstable. This means that WGC arguments favor a SUSY version of the SM, independently of the usual hierarchy problem arguments. In a T 2 /Z 4 compactification in which the orbifold action is embedded into the B - L symmetry the bounds on neutrino masses and the cosmological constant are recovered. This suggests that the MSSM should be extended with a U(1) B- L gauge group. In other families of vacua the spectrum of SUSY particles is further constrained in order to avoid the appearance of new AdS vacua or instabilities. We discuss a possible understanding of the little hierarchy problem in this context.

Gravity Waves and Linear Inflation From Axion Monodromy

DOE Office of Scientific and Technical Information (OSTI.GOV)

McAllister, Liam; /Cornell U., LEPP /Cornell U., Phys. Dept.; Silverstein, Eva

2010-08-26

Wrapped branes in string compactifications introduce a monodromy that extends the field range of individual closed-string axions to beyond the Planck scale. Furthermore, approximate shift symmetries of the system naturally control corrections to the axion potential. This suggests a general mechanism for chaotic inflation driven by monodromy-extended closed-string axions. We systematically analyze this possibility and show that the mechanism is compatible with moduli stabilization and can be realized in many types of compactifications, including warped Calabi-Yau manifolds and more general Ricci-curved spaces. In this broad class of models, the potential is linear in the canonical inflaton field, predicting a tensormore » to scalar ratio r {approx} 0.07 accessible to upcoming cosmic microwave background (CMB) observations.« less

Toda theory from six dimensions

NASA Astrophysics Data System (ADS)

Córdova, Clay; Jafferis, Daniel L.

2017-12-01

We describe a compactification of the six-dimensional (2,0) theory on a foursphere which gives rise to a two-dimensional Toda theory at long distances. This construction realizes chiral Toda fields as edge modes trapped near the poles of the sphere. We relate our setup to compactifications of the (2,0) theory on the five and six-sphere. In this way, we explain a connection between half-BPS operators of the (2,0) theory and twodimensional W-algebras, and derive an equality between their conformal anomalies. As we explain, all such relationships between the six-dimensional (2,0) theory and Toda field theory can be interpreted as statements about the edge modes of complex Chern-Simons on various three-manifolds with boundary.

Atlas of solar hidden photon emission

DOE Office of Scientific and Technical Information (OSTI.GOV)

Redondo, Javier, E-mail: redondo@mpp.mpg.de

2015-07-01

Hidden photons, gauge bosons of a U(1) symmetry of a hidden sector, can constitute the dark matter of the universe and a smoking gun for large volume compactifications of string theory. In the sub-eV mass range, a possible discovery experiment consists on searching the copious flux of these particles emitted from the Sun in a helioscope setup à la Sikivie. In this paper, we compute in great detail the flux of HPs from the Sun, a necessary ingredient for interpreting such experiments. We provide a detailed exposition of transverse photon-HP oscillations in inhomogenous media, with special focus on resonance oscillations,more » which play a leading role in many cases. The region of the Sun emitting HPs resonantly is a thin spherical shell for which we justify an averaged-emission formula and which implies a distinctive morphology of the angular distribution of HPs on Earth in many cases. Low mass HPs with energies in the visible and IR have resonances very close to the photosphere where the solar plasma is not fully ionised and requires building a detailed model of solar refraction and absorption. We present results for a broad range of HP masses (from 0–1 keV) and energies (from the IR to the X-ray range), the most complete atlas of solar HP emission to date.« less

Atlas of solar hidden photon emission

DOE Office of Scientific and Technical Information (OSTI.GOV)

Redondo, Javier; Max-Planck-Institut für Physik, Werner-Heisenberg-Institut,Föhringer Ring 6, 80805 München

2015-07-20

Hidden photons, gauge bosons of a U(1) symmetry of a hidden sector, can constitute the dark matter of the universe and a smoking gun for large volume compactifications of string theory. In the sub-eV mass range, a possible discovery experiment consists on searching the copious flux of these particles emitted from the Sun in a helioscope setup à la Sikivie. In this paper, we compute in great detail the flux of HPs from the Sun, a necessary ingredient for interpreting such experiments. We provide a detailed exposition of transverse photon-HP oscillations in inhomogenous media, with special focus on resonance oscillations,more » which play a leading role in many cases. The region of the Sun emitting HPs resonantly is a thin spherical shell for which we justify an averaged-emission formula and which implies a distinctive morphology of the angular distribution of HPs on Earth in many cases. Low mass HPs with energies in the visible and IR have resonances very close to the photosphere where the solar plasma is not fully ionised and requires building a detailed model of solar refraction and absorption. We present results for a broad range of HP masses (from 0–1 keV) and energies (from the IR to the X-ray range), the most complete atlas of solar HP emission to date.« less

Universal moduli spaces of Riemann surfaces

NASA Astrophysics Data System (ADS)

Ji, Lizhen; Jost, Jürgen

2017-04-01

We construct a moduli space for Riemann surfaces that is universal in the sense that it represents compact Riemann surfaces of any finite genus. This moduli space is a connected complex subspace of an infinite dimensional complex space, and is stratified according to genus such that each stratum has a compact closure, and it carries a metric and a measure that induce a Riemannian metric and a finite volume measure on each stratum. Applications to the Plateau-Douglas problem for minimal surfaces of varying genus and to the partition function of Bosonic string theory are outlined. The construction starts with a universal moduli space of Abelian varieties. This space carries a structure of an infinite dimensional locally symmetric space which is of interest in its own right. The key to our construction of the universal moduli space then is the Torelli map that assigns to every Riemann surface its Jacobian and its extension to the Satake-Baily-Borel compactifications.

ISLES: Probing Extra Dimensions Using a Superconducting Accelerometer

NASA Technical Reports Server (NTRS)

Paik, Ho Jung; Moody, M. Vol; Prieto-Gortcheva, Violeta A.

2003-01-01

In string theories, extra dimensions must be compactified. The possibility that gravity can have large radii of compactification leads to a violation of the inverse square law at submillimeter distances. The objective of ISLES is to perform a null test of Newton s law in space with a resolution of one part in 10(exp 5) or better at 100 microns. The experiment will be cooled to less than or equal to 2 K, which permits superconducting magnetic levitation of the test masses. To minimize Newtonian errors, ISLES employs a near null source, a circular disk of large diameter-to-thickness ratio. Two test masses, also disk-shaped, are suspended on the two sides of the source mass at a nominal distance of 100 microns. The signal is detected by a superconducting differential accelerometer. A ground test apparatus is under construction.

Axion monodromy and the weak gravity conjecture

NASA Astrophysics Data System (ADS)

Hebecker, Arthur; Rompineve, Fabrizio; Westphal, Alexander

2016-04-01

Axions with broken discrete shift symmetry (axion monodromy) have recently played a central role both in the discussion of inflation and the `relaxion' approach to the hierarchy problem. We suggest a very minimalist way to constrain such models by the weak gravity conjecture for domain walls: while the electric side of the conjecture is always satisfied if the cosine-oscillations of the axion potential are sufficiently small, the magnetic side imposes a cutoff, Λ3 ˜ mf M pl, independent of the height of these `wiggles'. We compare our approach with the recent related proposal by Ibanez, Montero, Uranga and Valenzuela. We also discuss the non-trivial question which version, if any, of the weak gravity conjecture for domain walls should hold. In particular, we show that string compactifications with branes of different dimensions wrapped on different cycles lead to a `geometric weak gravity conjecture' relating volumes of cycles, norms of corresponding forms and the volume of the compact space. Imposing this `geometric conjecture', e.g. on the basis of the more widely accepted weak gravity conjecture for particles, provides at least some support for the (electric and magnetic) conjecture for domain walls.

Enhanced gauge symmetry in type II and F-theory compactifications: Dynkin diagrams from polyhedra

NASA Astrophysics Data System (ADS)

Perevalov, Eugene; Skarke, Harald

1997-02-01

We explain the observation by Candelas and Font that the Dynkin diagrams of non-abelian gauge groups occurring in type IIA and F-theory can be read off from the polyhedron Δ ∗ that provides the toric description of the Calabi-Yau manifold used for compactification. We show how the intersection pattern of toric divisors corresponding to the degeneration of elliptic fibers follows the ADE classification of singularities and the Kodaira classification of degenerations. We treat in detail the cases of elliptic K3 surfaces and K3 fibered threefolds where the fiber is again elliptic. We also explain how even the occurrence of monodromy and non-simply laced groups in the latter case is visible in the toric picture. These methods also work in the fourfold case.

R2 dark energy in the laboratory

NASA Astrophysics Data System (ADS)

Brax, Philippe; Valageas, Patrick; Vanhove, Pierre

2018-05-01

We analyze the role, on large cosmological scales and laboratory experiments, of the leading curvature squared contributions to the low-energy effective action of gravity. We argue for a natural relationship c0λ2≃1 at low energy between the R2 coefficients c0 of the Ricci scalar squared term in this expansion and the dark energy scale Λ =(λ MPl)4 in four-dimensional Planck mass units. We show how the compatibility between the acceleration of the expansion rate of the Universe, local tests of gravity and the quantum stability of the model all converge to select such a relationship up to a coefficient which should be determined experimentally. When embedding this low-energy theory of gravity into candidates for its ultraviolet completion, we find that the proposed relationship is guaranteed in string-inspired supergravity models with modulus stabilization and supersymmetry breaking leading to de Sitter compactifications. In this case, the scalar degree of freedom of R2 gravity is associated to a volume modulus. Once written in terms of a scalar-tensor theory, the effective theory corresponds to a massive scalar field coupled with the universal strength β =1 /√{6 } to the matter stress-energy tensor. When the relationship c0λ2≃1 is realized, we find that on astrophysical scales and in cosmology the scalar field is ultralocal and therefore no effect arises on such large scales. On the other hand, the scalar field mass is tightly constrained by the nonobservation of fifth forces in torsion pendulum experiments such as Eöt-Wash. It turns out that the observation of the dark energy scale in cosmology implies that the scalar field could be detectable by fifth-force experiments in the near future.

Systematic Phenomenology on the Landscape of Calabi-Yau Hypersurfaces in Toric Varieties

NASA Astrophysics Data System (ADS)

Altman, Ross

The largest known database of Calabi-Yau threefold string vacua was famously produced by Kreuzer and Skarke in the form of a complete construction of all 473,800,776 reflexive polyhedra that exist in four dimensions [1]. These reflexive polyhedra describe the singu- lar limits of ambient Gorenstein toric Fano varieties in which Calabi-Yau threefolds are known to exist as the associated anticanonical hypersurfaces. In this thesis, we review how to unpack the topological and geometric information describing these Calabi-Yau threefolds using the toric construction, and provide, in a companion online database (see www.rossealtman.com), a detailed inventory of these quantities which are of interest to string phenomenologists. Many of the singular ambient varieties associated to the Kreuzer-Skarke list can be partially smoothed out into a multiplicity of distinct, terminal toric ambient spaces, each of which may embed a unique Calabi-Yau threefold. Some, however are not unique, and can be identified through topological and smoothness con- straints. A distribution of the unique Calabi-Yau threefolds which can be obtained from each 4D reflexive polyhedron, will be provided up to current computational limits. In addition, we will detail the computation of a variety of quantities associated to each of these vacua, such as the Chern classes, Hodge data, intersection numbers, and the Kahler and Mori cones. Then, moving on to actual string phenomenology on the Calabi-Yau compactification vacua, we outline the prescription for moduli stabilization with a supersymmetry breaking vacuum known as the LARGE Volume Scenario (LVS), paying particular attention to the so-called "Swiss cheese" models. It is an important open problem in string model building to identify the set of Swiss cheese solutions within the space of Calabi-Yau threefolds. In this thesis, we present an algorithm to isolate a special subset of Swiss cheese solutions that are characterized by "holes," or small 4-cycles in homology, descending from the toric divisors inherent to the original four dimensional reflexive polyhedra. Implementing these methods, we find 2,313 "toric" Swiss cheese manifolds, over half of which have h1,1 = 6. Of these, 70 have two or more large 4-cycles and a flat direction in the effective potential. In an explicit example, we find a stable minimum for the small Kahler moduli and a flat direction in the large moduli. Finally, we approach the subject of orientifolding the Calabi-Yau threefold vacuum of a type IIB theory in order to break N = 2 supergravity down to N = 1 in the low energy effective theory. To this end, we describe the process of choosing a non-trivial Z 2 involution, and locating its fixed points on the compactification manifold. It will be shown that consistency of this involution across the full Kahler cone is very restrictive and results in at most O3/O7 planes in nearly every case. We also discuss the splitting of the Kahler moduli space of the orientifold into even and odd parity components, and present concrete examples demonstrating this process.

Search for diphoton events with large missing transverse energy in 6.3  fb(-1) of pp collisions at √s=1.96  TeV.

PubMed

Abazov, V M; Abbott, B; Abolins, M; Acharya, B S; Adams, M; Adams, T; Alexeev, G D; Alkhazov, G; Alton, A; Alverson, G; Alves, G A; Ancu, L S; Aoki, M; Arnoud, Y; Arov, M; Askew, A; Asman, B; Atramentov, O; Avila, C; Backusmayes, J; Badaud, F; Bagby, L; Baldin, B; Bandurin, D V; Banerjee, S; Barberis, E; Baringer, P; Barreto, J; Bartlett, J F; Bassler, U; Beale, S; Bean, A; Begalli, M; Begel, M; Belanger-Champagne, C; Bellantoni, L; Benitez, J A; Beri, S B; Bernardi, G; Bernhard, R; Bertram, I; Besançon, M; Beuselinck, R; Bezzubov, V A; Bhat, P C; Bhatnagar, V; Blazey, G; Blessing, S; Bloom, K; Boehnlein, A; Boline, D; Bolton, T A; Boos, E E; Borissov, G; Bose, T; Brandt, A; Brandt, O; Brock, R; Brooijmans, G; Bross, A; Brown, D; Brown, J; Bu, X B; Buchholz, D; Buehler, M; Buescher, V; Bunichev, V; Burdin, S; Burnett, T H; Buszello, C P; Calpas, B; Calvet, S; Camacho-Pérez, E; Carrasco-Lizarraga, M A; Carrera, E; Casey, B C K; Castilla-Valdez, H; Chakrabarti, S; Chakraborty, D; Chan, K M; Chandra, A; Chen, G; Chevalier-Théry, S; Cho, D K; Cho, S W; Choi, S; Choudhary, B; Christoudias, T; Cihangir, S; Claes, D; Clutter, J; Cooke, M S; Cooke, M; Cooper, W E; Corcoran, M; Couderc, F; Cousinou, M-C; Croc, A; Cutts, D; Cwiok, M; Das, A; Davies, G; De, K; de Jong, S J; De La Cruz-Burelo, E; Déliot, F; Demarteau, M; Demina, R; Denisov, D; Denisov, S P; Desai, S; Devaughan, K; Diehl, H T; Diesburg, M; Dominguez, A; Dorland, T; Dubey, A; Dudko, L V; Duggan, D; Duperrin, A; Dutt, S; Dyshkant, A; Eads, M; Edmunds, D; Ellison, J; Elvira, V D; Enari, Y; Eno, S; Evans, H; Evdokimov, A; Evdokimov, V N; Facini, G; Ferapontov, A V; Ferbel, T; Fiedler, F; Filthaut, F; Fisher, W; Fisk, H E; Fortner, M; Fox, H; Fuess, S; Gadfort, T; Garcia-Bellido, A; Gavrilov, V; Gay, P; Geist, W; Geng, W; Gerbaudo, D; Gerber, C E; Gershtein, Y; Ginther, G; Golovanov, G; Goussiou, A; Grannis, P D; Greder, S; Greenlee, H; Greenwood, Z D; Gregores, E M; Grenier, G; Gris, Ph; Grivaz, J-F; Grohsjean, A; Grünendahl, S; Grünewald, M W; Guo, F; Guo, J; Gutierrez, G; Gutierrez, P; Haas, A; Hagopian, S; Haley, J; Han, L; Harder, K; Harel, A; Hauptman, J M; Hays, J; Hebbeker, T; Hedin, D; Hegab, H; Heinson, A P; Heintz, U; Hensel, C; Heredia-De La Cruz, I; Herner, K; Hesketh, G; Hildreth, M D; Hirosky, R; Hoang, T; Hobbs, J D; Hoeneisen, B; Hohlfeld, M; Hossain, S; Hubacek, Z; Huske, N; Hynek, V; Iashvili, I; Illingworth, R; Ito, A S; Jabeen, S; Jaffré, M; Jain, S; Jamin, D; Jesik, R; Johns, K; Johnson, M; Johnston, D; Jonckheere, A; Jonsson, P; Joshi, J; Juste, A; Kaadze, K; Kajfasz, E; Karmanov, D; Kasper, P A; Katsanos, I; Kehoe, R; Kermiche, S; Khalatyan, N; Khanov, A; Kharchilava, A; Kharzheev, Y N; Khatidze, D; Kirby, M H; Kohli, J M; Kozelov, A V; Kraus, J; Kumar, A; Kupco, A; Kurča, T; Kuzmin, V A; Kvita, J; Lammers, S; Landsberg, G; Lebrun, P; Lee, H S; Lee, S W; Lee, W M; Lellouch, J; Li, L; Li, Q Z; Lietti, S M; Lim, J K; Lincoln, D; Linnemann, J; Lipaev, V V; Lipton, R; Liu, Y; Liu, Z; Lobodenko, A; Lokajicek, M; Love, P; Lubatti, H J; Luna-Garcia, R; Lyon, A L; Maciel, A K A; Mackin, D; Madar, R; Magaña-Villalba, R; Malik, S; Malyshev, V L; Maravin, Y; Martínez-Ortega, J; McCarthy, R; McGivern, C L; Meijer, M M; Melnitchouk, A; Menezes, D; Mercadante, P G; Merkin, M; Meyer, A; Meyer, J; Mondal, N K; Muanza, G S; Mulhearn, M; Nagy, E; Naimuddin, M; Narain, M; Nayyar, R; Neal, H A; Negret, J P; Neustroev, P; Nilsen, H; Novaes, S F; Nunnemann, T; Obrant, G; Onoprienko, D; Orduna, J; Osman, N; Osta, J; Otero Y Garzón, G J; Owen, M; Padilla, M; Pangilinan, M; Parashar, N; Parihar, V; Park, S K; Parsons, J; Partridge, R; Parua, N; Patwa, A; Penning, B; Perfilov, M; Peters, K; Peters, Y; Petrillo, G; Pétroff, P; Piegaia, R; Piper, J; Pleier, M-A; Podesta-Lerma, P L M; Podstavkov, V M; Pol, M-E; Polozov, P; Popov, A V; Prewitt, M; Price, D; Protopopescu, S; Qian, J; Quadt, A; Quinn, B; Rangel, M S; Ranjan, K; Ratoff, P N; Razumov, I; Renkel, P; Rich, P; Rijssenbeek, M; Ripp-Baudot, I; Rizatdinova, F; Rominsky, M; Royon, C; Rubinov, P; Ruchti, R; Safronov, G; Sajot, G; Sánchez-Hernández, A; Sanders, M P; Sanghi, B; Santos, A S; Savage, G; Sawyer, L; Scanlon, T; Schamberger, R D; Scheglov, Y; Schellman, H; Schliephake, T; Schlobohm, S; Schwanenberger, C; Schwienhorst, R; Sekaric, J; Severini, H; Shabalina, E; Shary, V; Shchukin, A A; Shivpuri, R K; Simak, V; Sirotenko, V; Skubic, P; Slattery, P; Smirnov, D; Smith, K J; Snow, G R; Snow, J; Snyder, S; Söldner-Rembold, S; Sonnenschein, L; Sopczak, A; Sosebee, M; Soustruznik, K; Spurlock, B; Stark, J; Stolin, V; Stoyanova, D A; Strauss, E; Strauss, M; Strom, D; Stutte, L; Svoisky, P; Takahashi, M; Tanasijczuk, A; Taylor, W; Titov, M; Tokmenin, V V; Tsybychev, D; Tuchming, B; Tully, C; Tuts, P M; Uvarov, L; Uvarov, S; Uzunyan, S; Van Kooten, R; van Leeuwen, W M; Varelas, N; Varnes, E W; Vasilyev, I A; Verdier, P; Vertogradov, L S; Verzocchi, M; Vesterinen, M; Vilanova, D; Vint, P; Vokac, P; Wahl, H D; Wang, M H L S; Warchol, J; Watts, G; Wayne, M; Weber, M; Wetstein, M; White, A; Wicke, D; Williams, M R J; Wilson, G W; Wimpenny, S J; Wobisch, M; Wood, D R; Wyatt, T R; Xie, Y; Xu, C; Yacoob, S; Yamada, R; Yang, W-C; Yasuda, T; Yatsunenko, Y A; Ye, Z; Yin, H; Yip, K; Yoo, H D; Youn, S W; Yu, J; Zelitch, S; Zhao, T; Zhou, B; Zhou, N; Zhu, J; Zielinski, M; Zieminska, D; Zivkovic, L

2010-11-26

We report a search for diphoton events with large missing transverse energy produced in pp collisions at √s=1.96  TeV. The data were collected with the D0 detector at the Fermilab Tevatron Collider and correspond to 6.3  fb(-1) of integrated luminosity. The observed missing transverse energy distribution is well described by the standard model prediction, and 95% C.L. limits are derived on two realizations of theories beyond the standard model. In a gauge-mediated supersymmetry breaking scenario, the breaking scale Λ is excluded for Λ<124  TeV. In a universal extra dimension model including gravitational decays, the compactification radius R(c) is excluded for R(c)(-1)<477  GeV.

One-loop Pfaffians and large-field inflation in string theory

NASA Astrophysics Data System (ADS)

Ruehle, Fabian; Wieck, Clemens

2017-06-01

We study the consistency of large-field inflation in low-energy effective field theories of string theory. In particular, we focus on the stability of Kähler moduli in the particularly interesting case where the non-perturbative superpotential of the Kähler sector explicitly depends on the inflaton field. This situation arises generically due to one-loop corrections to the instanton action. The field dependence of the modulus potential feeds back into the inflationary dynamics, potentially impairing slow roll. We distinguish between world-sheet instantons from Euclidean D-branes, which typically yield polynomial one-loop Pfaffians, and gaugino condensates, which can yield exponential or periodic corrections. In all scenarios successful slow-roll inflation imposes bounds on the magnitude of the one-loop correction, corresponding to constraints on possible compactifications. While we put a certain emphasis on Type IIB constructions with mobile D7-branes, our results seem to apply more generally.

An infinite swampland of U(1) charge spectra in 6D supergravity theories

NASA Astrophysics Data System (ADS)

Taylor, Washington; Turner, Andrew P.

2018-06-01

We analyze the anomaly constraints on 6D supergravity theories with a single abelian U(1) gauge factor. For theories with charges restricted to q = ±1 , ±2 and no tensor multiplets, anomaly-free models match those models that can be realized from F-theory compactifications almost perfectly. For theories with tensor multiplets or with larger charges, the F-theory constraints are less well understood. We show, however, that there is an infinite class of distinct massless charge spectra in the "swampland" of theories that satisfy all known quantum consistency conditions but do not admit a realization through F-theory or any other known approach to string compactification. We also compare the spectra of charged matter in abelian theories with those that can be realized from breaking nonabelian SU(2) and higher rank gauge symmetries.

A model to study finite-size and magnetic effects on the phase transition of a fermion interacting system

NASA Astrophysics Data System (ADS)

Corrêa, Emerson B. S.; Linhares, César A.; Malbouisson, Adolfo P. C.

2018-03-01

We present a model to study the effects from external magnetic field, chemical potential and finite size on the phase structures of a massive four- and six-fermion interacting systems. These effects are introduced by a method of compactification of coordinates, a generalization of the standard Matsubara prescription. Through the compactification of the z-coordinate and of imaginary time, we describe a heated system with the shape of a film of thickness L, at temperature β-1 undergoing first- or second-order phase transition. We have found a strong dependence of the temperature transition on the coupling constants λ and η. Besides inverse magnetic catalysis and symmetry breaking for both kinds of transition, we have found an inverse symmetry breaking phenomenon with respect to first-order phase transition.

Yang-Mills theory and the ABC conjecture

NASA Astrophysics Data System (ADS)

He, Yang-Hui; Hu, Zhi; Probst, Malte; Read, James

2018-05-01

We establish a precise correspondence between the ABC Conjecture and 𝒩 = 4 super-Yang-Mills theory. This is achieved by combining three ingredients: (i) Elkies’ method of mapping ABC-triples to elliptic curves in his demonstration that ABC implies Mordell/Faltings; (ii) an explicit pair of elliptic curve and associated Belyi map given by Khadjavi-Scharaschkin; and (iii) the fact that the bipartite brane-tiling/dimer model for a gauge theory with toric moduli space is a particular dessin d’enfant in the sense of Grothendieck. We explore this correspondence for the highest quality ABC-triples as well as large samples of random triples. The conjecture itself is mapped to a statement about the fundamental domain of the toroidal compactification of the string realization of 𝒩 = 4 SYM.

Global embeddings for branes at toric singularities

NASA Astrophysics Data System (ADS)

Balasubramanian, Vijay; Berglund, Per; Braun, Volker; García-Etxebarria, Iñaki

2012-10-01

We describe how local toric singularities, including the Toric Lego construction, can be embedded in compact Calabi-Yau manifolds. We study in detail the addition of D-branes, including non-compact flavor branes as typically used in semi-realistic model building. The global geometry provides constraints on allowable local models. As an illustration of our discussion we focus on D3 and D7-branes on (the partially resolved) ( dP 0)3 singularity, its embedding in a specific Calabi-Yau manifold as a hypersurface in a toric variety, the related type IIB orientifold compactification, as well as the corresponding F-theory uplift. Our techniques generalize naturally to complete intersections, and to a large class of F-theory backgrounds with singularities.

Small instanton transitions for M5 fractions

NASA Astrophysics Data System (ADS)

Mekareeya, Noppadol; Ohmori, Kantaro; Shimizu, Hiroyuki; Tomasiello, Alessandro

2017-10-01

M5-branes on an ADE singularity are described by certain six-dimensional "conformal matter" superconformal field theories. Their Higgs moduli spaces contain information about various dynamical processes for the M5s; however, they are not directly accessible due to the lack of a Lagrangian formulation. Using anomaly matching, we compute their dimensions. The result implies that M5 fractions can recombine in several different ways, where the M5s are leaving behind frozen versions of the singularity. The anomaly polynomial gives hints about the nature of the freezing. We also check the Higgs dimension formula by comparing it with various existing conjectures for the CFTs one obtains by torus compactifications down to four and three dimensions. Aided by our results, we also extend those conjectures to compactifications of theories not previously considered. These involve class S theories with twisted punctures in four dimensions, and affine-Dynkin-shaped quivers in three dimensions.

The Infinitesimal Moduli Space of Heterotic G 2 Systems

NASA Astrophysics Data System (ADS)

de la Ossa, Xenia; Larfors, Magdalena; Svanes, Eirik E.

2018-06-01

Heterotic string compactifications on integrable G 2 structure manifolds Y with instanton bundles {(V,A), (TY,\\tilde{θ})} yield supersymmetric three-dimensional vacua that are of interest in physics. In this paper, we define a covariant exterior derivative D and show that it is equivalent to a heterotic G 2 system encoding the geometry of the heterotic string compactifications. This operator D acts on a bundle Q}=T^*Y \\oplus End(V) \\oplus End(TY)} and satisfies a nilpotency condition \\check{{D^2=0} , for an appropriate projection of D. Furthermore, we determine the infinitesimal moduli space of these systems and show that it corresponds to the finite-dimensional cohomology group H^1_{D}(Q). We comment on the similarities and differences of our result with Atiyah's well-known analysis of deformations of holomorphic vector bundles over complex manifolds. Our analysis leads to results that are of relevance to all orders in the {α'} expansion.

General relativity with small cosmological constant from spontaneous compactification of Lovelock theory in vacuum

DOE Office of Scientific and Technical Information (OSTI.GOV)

Canfora, Fabrizio; Willison, Steven; Giacomini, Alex

2009-08-15

It is shown that Einstein gravity in four dimensions with small cosmological constant and small extra dimensions can be obtained by spontaneous compactification of Lovelock gravity in vacuum. Assuming that the extra dimensions are compact spaces of constant curvature, general relativity is recovered within a certain class of Lovelock theories possessing necessarily cubic or higher order terms in curvature. This bounds the higher dimension to at least 7. Remarkably, the effective gauge coupling and Newton constant in four dimensions are not proportional to the gravitational constant in higher dimensions, but are shifted with respect to their standard values. This effectmore » opens up new scenarios where a maximally symmetric solution in higher dimensions could decay into the compactified spacetime either by tunneling or through a gravitational analog of ghost condensation. Indeed, this is what occurs requiring both the extra dimensions and the four-dimensional cosmological constant to be small.« less

Compactification and inflation in the superstring theory from the condensation of gravitino pairs

NASA Astrophysics Data System (ADS)

Pollock, M. D.

1987-12-01

We discuss the possibility that inflation can occur in the E8×E8' heterotic superstring theory, if there is a pair condensation of the gravitino field ψA and also of the Majorana-Weyl spinor λ, as suggested by the Helayël-Neto and Smith. In the absence of a condensation of the anti-symmetric tensor field HMNP, then the associated potential V(θ,φ) is bounded from below and independent of the dilaton field φ. It can be made to vanish at the minimum, where the compactification scale θ is fixed. Alternatively, a small cosmological constant may remain (ultimately to be cancelled by radiative corrections at the lower energy scale of the gaugino condensation), which could in principle lead to inflation. Present address: Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Bombay 400 005, India.

D-brane instantons and the effective field theory of flux compactifications

NASA Astrophysics Data System (ADS)

Uranga, Angel M.

2009-01-01

We provide a description of the effects of fluxes on euclidean D-brane instantons purely in terms of the 4d effective action. The effect corresponds to the dressing of the effective non-perturbative 4d effective vertex with 4d flux superpotential interactions, generated when the moduli fields made massive by the flux are integrated out. The description in terms of effective field theory allows a unified description of non-perturbative effects in all flux compactifications of a given underlying fluxless model, globally in the moduli space of the latter. It also allows us to describe explicitly the effects on D-brane instantons of fluxes with no microscopic description, like non-geometric fluxes. At the more formal level, the description has interesting connections with the bulk-boundary map of open-closed two-dimensional topological string theory, and with the Script N = 1 special geometry.

Algorithmic universality in F-theory compactifications

NASA Astrophysics Data System (ADS)

Halverson, James; Long, Cody; Sung, Benjamin

2017-12-01

We study universality of geometric gauge sectors in the string landscape in the context of F-theory compactifications. A finite time construction algorithm is presented for 4/3 ×2.96 ×10755 F-theory geometries that are connected by a network of topological transitions in a connected moduli space. High probability geometric assumptions uncover universal structures in the ensemble without explicitly constructing it. For example, non-Higgsable clusters of seven-branes with intricate gauge sectors occur with a probability above 1 - 1.01 ×10-755 , and the geometric gauge group rank is above 160 with probability 0.999995. In the latter case there are at least 10 E8 factors, the structure of which fixes the gauge groups on certain nearby seven-branes. Visible sectors may arise from E6 or S U (3 ) seven-branes, which occur in certain random samples with probability ≃1 /200 .

All possible electroweak models from Z orbifold

NASA Astrophysics Data System (ADS)

Sato, Hikaru; Kataoka, H.; Munakata, H.; Tanaka, S.

1992-02-01

Considering all possible combinations of two Wilson lines, it is shown that only three independent electroweak models with three generations are obtained from Z orbifold compactification. We obtain this result by analyzing particle spectra of both untwisted and twisted sectors explicitly.

All possible electroweak models from Z orbifold

NASA Astrophysics Data System (ADS)

Sato, H.; Kataoka, H.; Munakata, H.; Tanaka, S.

Considering all possible combinations of two Wilson lines it is shown that only three independent electroweak models with three generations are obtained from Z orbifold compactification. We obtain this result by analyzing particle spectra of both untwisted and twisted sectors explicitly.

The semi-classical expansion and resurgence in gauge theories: new perturbative, instanton, bion, and renormalon effects

DOE PAGES

Argyres, Philip C.; Uensal, Mithat

2012-08-10

We study the dynamics of four dimensional gauge theories with adjoint fermions for all gauge groups, both in perturbation theory and non-perturbatively, by using circle compactification with periodic boundary conditions for the fermions. There are new gauge phenomena. We show that, to all orders in perturbation theory, many gauge groups are Higgsed by the gauge holonomy around the circle to a product of both abelian and nonabelian gauge group factors. Non-perturbatively there are monopole-instantons with fermion zero modes and two types of monopole-anti-monopole molecules, called bions. One type are magnetic bions which carry net magnetic charge and induce a massmore » gap for gauge fluctuations. Another type are neutral bions which are magnetically neutral, and their understanding requires a generalization of multi-instanton techniques in quantum mechanics — which we refer to as the Bogomolny-Zinn-Justin (BZJ) prescription — to compactified field theory. The BZJ prescription applied to bion-anti-bion topological molecules predicts a singularity on the positive real axis of the Borel plane (i.e., a divergence from summing large orders in peturbation theory) which is of order N times closer to the origin than the leading 4-d BPST instanton-anti-instanton singularity, where N is the rank of the gauge group. The position of the bion-anti-bion singularity is thus qualitatively similar to that of the 4-d IR renormalon singularity, and we conjecture that they are continuously related as the compactification radius is changed. By making use of transseries and Écalle’s resurgence theory we argue that a non-perturbative continuum definition of a class of field theories which admit semi-classical expansions may be possible.« less

The large N limit of superconformal field theories and supergravity

NASA Astrophysics Data System (ADS)

Maldacena, Juan

1999-07-01

We show that the large N limit of certain conformal field theories in various dimensions include in their Hilbert space a sector describing supergravity on the product of Anti-deSitter spacetimes, spheres and other compact manifolds. This is shown by taking some branes in the full M/string theory and then taking a low energy limit where the field theory on the brane decouples from the bulk. We observe that, in this limit, we can still trust the near horizon geometry for large N. The enhanced supersymmetries of the near horizon geometry correspond to the extra supersymmetry generators present in the superconformal group (as opposed to just the super-Poincare group). The 't Hooft limit of 3+1N=4 super-Yang-Mills at the conformal point is shown to contain strings: they are IIB strings. We conjecture that compactifications of M/string theory on various Anti-deSitter spacetimes is dual to various conformal field theories. This leads to a new proposal for a definition of M-theory which could be extended to include five non-compact dimensions.

Search for diphoton events with large missing transverse energy with 36 pb-1 of 7 TeV proton-proton collision data with the ATLAS detector

NASA Astrophysics Data System (ADS)

Aad, G.; Abbott, B.; Abdallah, J.; Abdelalim, A. A.; Abdesselam, A.; Abdinov, O.; Abi, B.; Abolins, M.; Abramowicz, H.; Abreu, H.; Acerbi, E.; Acharya, B. S.; Adams, D. L.; Addy, T. N.; Adelman, J.; Aderholz, M.; Adomeit, S.; Adragna, P.; Adye, T.; Aefsky, S.; Aguilar-Saavedra, J. A.; Aharrouche, M.; Ahlen, S. P.; Ahles, F.; Ahmad, A.; Ahsan, M.; Aielli, G.; Akdogan, T.; Åkesson, T. P. A.; Akimoto, G.; Akimov, A. V.; Akiyama, A.; Alam, M. S.; Alam, M. A.; Albert, J.; Albrand, S.; Aleksa, M.; Aleksandrov, I. N.; Alessandria, F.; Alexa, C.; Alexander, G.; Alexandre, G.; Alexopoulos, T.; Alhroob, M.; Aliev, M.; Alimonti, G.; Alison, J.; Aliyev, M.; Allport, P. P.; Allwood-Spiers, S. E.; Almond, J.; Aloisio, A.; Alon, R.; Alonso, A.; Alviggi, M. G.; Amako, K.; Amaral, P.; Amelung, C.; Ammosov, V. V.; Amorim, A.; Amorós, G.; Amram, N.; Anastopoulos, C.; Andari, N.; Andeen, T.; Anders, C. F.; Anderson, K. J.; Andreazza, A.; Andrei, V.; Andrieux, M.-L.; Anduaga, X. S.; Angerami, A.; Anghinolfi, F.; Anjos, N.; Annovi, A.; Antonaki, A.; Antonelli, M.; Antonov, A.; Antos, J.; Anulli, F.; Aoun, S.; Aperio Bella, L.; Apolle, R.; Arabidze, G.; Aracena, I.; Arai, Y.; Arce, A. T. H.; Archambault, J. P.; Arfaoui, S.; Arguin, J.-F.; Arik, E.; Arik, M.; Armbruster, A. J.; Arnaez, O.; Arnault, C.; Artamonov, A.; Artoni, G.; Arutinov, D.; Asai, S.; Asfandiyarov, R.; Ask, S.; Åsman, B.; Asquith, L.; Assamagan, K.; Astbury, A.; Astvatsatourov, A.; Atoian, G.; Aubert, B.; Auerbach, B.; Auge, E.; Augsten, K.; Aurousseau, M.; Austin, N.; Avramidou, R.; Axen, D.; Ay, C.; Azuelos, G.; Azuma, Y.; Baak, M. A.; Baccaglioni, G.; Bacci, C.; Bach, A. M.; Bachacou, H.; Bachas, K.; Bachy, G.; Backes, M.; Backhaus, M.; Badescu, E.; Bagnaia, P.; Bahinipati, S.; Bai, Y.; Bailey, D. C.; Bain, T.; Baines, J. T.; Baker, O. K.; Baker, M. D.; Baker, S.; Dos Santos Pedrosa, F. Baltasar; Banas, E.; Banerjee, P.; Banerjee, Sw.; Banfi, D.; Bangert, A.; Bansal, V.; Bansil, H. S.; Barak, L.; Baranov, S. P.; Barashkou, A.; Barbaro Galtieri, A.; Barber, T.; Barberio, E. L.; Barberis, D.; Barbero, M.; Bardin, D. Y.; Barillari, T.; Barisonzi, M.; Barklow, T.; Barlow, N.; Barnett, B. M.; Barnett, R. M.; Baroncelli, A.; Barone, G.; Barr, A. J.; Barreiro, F.; Barreiro Guimarães da Costa, J.; Barrillon, P.; Bartoldus, R.; Barton, A. E.; Bartsch, D.; Bartsch, V.; Bates, R. L.; Batkova, L.; Batley, J. R.; Battaglia, A.; Battistin, M.; Battistoni, G.; Bauer, F.; Bawa, H. S.; Beare, B.; Beau, T.; Beauchemin, P. H.; Beccherle, R.; Bechtle, P.; Beck, H. P.; Beckingham, M.; Becks, K. H.; Beddall, A. J.; Beddall, A.; Bedikian, S.; Bednyakov, V. A.; Bee, C. P.; Begel, M.; Harpaz, S. Behar; Behera, P. K.; Beimforde, M.; Belanger-Champagne, C.; Bell, P. J.; Bell, W. H.; Bella, G.; Bellagamba, L.; Bellina, F.; Bellomo, M.; Belloni, A.; Beloborodova, O.; Belotskiy, K.; Beltramello, O.; Ami, S. Ben; Benary, O.; Benchekroun, D.; Benchouk, C.; Bendel, M.; Benedict, B. H.; Benekos, N.; Benhammou, Y.; Benjamin, D. P.; Benoit, M.; Bensinger, J. R.; Benslama, K.; Bentvelsen, S.; Berge, D.; Bergeaas Kuutmann, E.; Berger, N.; Berghaus, F.; Berglund, E.; Beringer, J.; Bernardet, K.; Bernat, P.; Bernhard, R.; Bernius, C.; Berry, T.; Bertin, A.; Bertinelli, F.; Bertolucci, F.; Besana, M. I.; Besson, N.; Bethke, S.; Bhimji, W.; Bianchi, R. M.; Bianco, M.; Biebel, O.; Bieniek, S. P.; Biesiada, J.; Biglietti, M.; Bilokon, H.; Bindi, M.; Binet, S.; Bingul, A.; Bini, C.; Biscarat, C.; Bitenc, U.; Black, K. M.; Blair, R. E.; Blanchard, J.-B.; Blanchot, G.; Blazek, T.; Blocker, C.; Blocki, J.; Blondel, A.; Blum, W.; Blumenschein, U.; Bobbink, G. J.; Bobrovnikov, V. B.; Bocchetta, S. S.; Bocci, A.; Boddy, C. R.; Boehler, M.; Boek, J.; Boelaert, N.; Böser, S.; Bogaerts, J. A.; Bogdanchikov, A.; Bogouch, A.; Bohm, C.; Boisvert, V.; Bold, T.; Boldea, V.; Bolnet, N. M.; Bona, M.; Bondarenko, V. G.; Boonekamp, M.; Boorman, G.; Booth, C. N.; Bordoni, S.; Borer, C.; Borisov, A.; Borissov, G.; Borjanovic, I.; Borroni, S.; Bos, K.; Boscherini, D.; Bosman, M.; Boterenbrood, H.; Botterill, D.; Bouchami, J.; Boudreau, J.; Bouhova-Thacker, E. V.; Boulahouache, C.; Bourdarios, C.; Bousson, N.; Boveia, A.; Boyd, J.; Boyko, I. R.; Bozhko, N. I.; Bozovic-Jelisavcic, I.; Bracinik, J.; Braem, A.; Branchini, P.; Brandenburg, G. W.; Brandt, A.; Brandt, G.; Brandt, O.; Bratzler, U.; Brau, B.; Brau, J. E.; Braun, H. M.; Brelier, B.; Bremer, J.; Brenner, R.; Bressler, S.; Breton, D.; Britton, D.; Brochu, F. M.; Brock, I.; Brock, R.; Brodbeck, T. J.; Brodet, E.; Broggi, F.; Bromberg, C.; Brooijmans, G.; Brooks, W. K.; Brown, G.; Brown, H.; Bruckman de Renstrom, P. A.; Bruncko, D.; Bruneliere, R.; Brunet, S.; Bruni, A.; Bruni, G.; Bruschi, M.; Buanes, T.; Bucci, F.; Buchanan, J.; Buchanan, N. J.; Buchholz, P.; Buckingham, R. M.; Buckley, A. G.; Buda, S. I.; Budagov, I. A.; Budick, B.; Büscher, V.; Bugge, L.; Buira-Clark, D.; Bulekov, O.; Bunse, M.; Buran, T.; Burckhart, H.; Burdin, S.; Burgess, T.; Burke, S.; Busato, E.; Bussey, P.; Buszello, C. P.; Butin, F.; Butler, B.; Butler, J. M.; Buttar, C. M.; Butterworth, J. M.; Buttinger, W.; Byatt, T.; Cabrera Urbán, S.; Caforio, D.; Cakir, O.; Calafiura, P.; Calderini, G.; Calfayan, P.; Calkins, R.; Caloba, L. P.; Caloi, R.; Calvet, D.; Calvet, S.; Camacho Toro, R.; Camarri, P.; Cambiaghi, M.; Cameron, D.; Campana, S.; Campanelli, M.; Canale, V.; Canelli, F.; Canepa, A.; Cantero, J.; Capasso, L.; Capeans Garrido, M. D. M.; Caprini, I.; Caprini, M.; Capriotti, D.; Capua, M.; Caputo, R.; Caramarcu, C.; Cardarelli, R.; Carli, T.; Carlino, G.; Carminati, L.; Caron, B.; Caron, S.; Carrillo Montoya, G. D.; Carter, A. A.; Carter, J. R.; Carvalho, J.; Casadei, D.; Casado, M. P.; Cascella, M.; Caso, C.; Castaneda Hernandez, A. M.; Castaneda-Miranda, E.; Castillo Gimenez, V.; Castro, N. F.; Cataldi, G.; Cataneo, F.; Catinaccio, A.; Catmore, J. R.; Cattai, A.; Cattani, G.; Caughron, S.; Cauz, D.; Cavalleri, P.; Cavalli, D.; Cavalli-Sforza, M.; Cavasinni, V.; Ceradini, F.; Cerqueira, A. S.; Cerri, A.; Cerrito, L.; Cerutti, F.; Cetin, S. A.; Cevenini, F.; Chafaq, A.; Chakraborty, D.; Chan, K.; Chapleau, B.; Chapman, J. D.; Chapman, J. W.; Chareyre, E.; Charlton, D. G.; Chavda, V.; Barajas, C. A. Chavez; Cheatham, S.; Chekanov, S.; Chekulaev, S. V.; Chelkov, G. A.; Chelstowska, M. A.; Chen, C.; Chen, H.; Chen, S.; Chen, T.; Chen, X.; Cheng, S.; Cheplakov, A.; Chepurnov, V. F.; Cherkaoui El Moursli, R.; Chernyatin, V.; Cheu, E.; Cheung, S. L.; Chevalier, L.; Chiefari, G.; Chikovani, L.; Childers, J. T.; Chilingarov, A.; Chiodini, G.; Chizhov, M. V.; Choudalakis, G.; Chouridou, S.; Christidi, I. A.; Christov, A.; Chromek-Burckhart, D.; Chu, M. L.; Chudoba, J.; Ciapetti, G.; Ciba, K.; Ciftci, A. K.; Ciftci, R.; Cinca, D.; Cindro, V.; Ciobotaru, M. D.; Ciocca, C.; Ciocio, A.; Cirilli, M.; Ciubancan, M.; Clark, A.; Clark, P. J.; Cleland, W.; Clemens, J. C.; Clement, B.; Clement, C.; Clifft, R. W.; Coadou, Y.; Cobal, M.; Coccaro, A.; Cochran, J.; Coe, P.; Cogan, J. G.; Coggeshall, J.; Cogneras, E.; Cojocaru, C. D.; Colas, J.; Colijn, A. P.; Collard, C.; Collins, N. J.; Collins-Tooth, C.; Collot, J.; Colon, G.; Conde Muiño, P.; Coniavitis, E.; Conidi, M. C.; Consonni, M.; Consorti, V.; Constantinescu, S.; Conta, C.; Conventi, F.; Cook, J.; Cooke, M.; Cooper, B. D.; Cooper-Sarkar, A. M.; Cooper-Smith, N. J.; Copic, K.; Cornelissen, T.; Corradi, M.; Corriveau, F.; Cortes-Gonzalez, A.; Cortiana, G.; Costa, G.; Costa, M. J.; Costanzo, D.; Costin, T.; Côté, D.; Coura Torres, R.; Courneyea, L.; Cowan, G.; Cowden, C.; Cox, B. E.; Cranmer, K.; Crescioli, F.; Cristinziani, M.; Crosetti, G.; Crupi, R.; Crépé-Renaudin, S.; Cuciuc, C.-M.; Almenar, C. Cuenca; Cuhadar Donszelmann, T.; Cuneo, S.; Curatolo, M.; Curtis, C. J.; Cwetanski, P.; Czirr, H.; Czyczula, Z.; D'Auria, S.; D'Onofrio, M.; D'Orazio, A.; Da Silva, P. V. M.; Da Via, C.; Dabrowski, W.; Dai, T.; Dallapiccola, C.; Dam, M.; Dameri, M.; Damiani, D. S.; Danielsson, H. O.; Dannheim, D.; Dao, V.; Darbo, G.; Darlea, G. L.; Daum, C.; Dauvergne, J. P.; Davey, W.; Davidek, T.; Davidson, N.; Davidson, R.; Davies, E.; Davies, M.; Davison, A. R.; Davygora, Y.; Dawe, E.; Dawson, I.; Dawson, J. W.; Daya, R. K.; De, K.; de Asmundis, R.; De Castro, S.; De Castro Faria Salgado, P. E.; De Cecco, S.; de Graat, J.; De Groot, N.; de Jong, P.; De La Taille, C.; De la Torre, H.; De Lotto, B.; De Mora, L.; De Nooij, L.; De Oliveira Branco, M.; De Pedis, D.; de Saintignon, P.; De Salvo, A.; De Sanctis, U.; De Santo, A.; De Vivie De Regie, J. B.; Dean, S.; Dedovich, D. V.; Degenhardt, J.; Dehchar, M.; Deile, M.; Del Papa, C.; Del Peso, J.; Del Prete, T.; Deliyergiyev, M.; Dell'Acqua, A.; Dell'Asta, L.; Della Pietra, M.; della Volpe, D.; Delmastro, M.; Delpierre, P.; Delruelle, N.; Delsart, P. A.; Deluca, C.; Demers, S.; Demichev, M.; Demirkoz, B.; Deng, J.; Denisov, S. P.; Derendarz, D.; Derkaoui, J. E.; Derue, F.; Dervan, P.; Desch, K.; Devetak, E.; Deviveiros, P. O.; Dewhurst, A.; DeWilde, B.; Dhaliwal, S.; Dhullipudi, R.; Di Ciaccio, A.; Di Ciaccio, L.; Di Girolamo, A.; Di Girolamo, B.; Di Luise, S.; Di Mattia, A.; Di Micco, B.; Di Nardo, R.; Di Simone, A.; Di Sipio, R.; Diaz, M. A.; Diblen, F.; Diehl, E. B.; Dietrich, J.; Dietzsch, T. A.; Diglio, S.; Dindar Yagci, K.; Dingfelder, J.; Dionisi, C.; Dita, P.; Dita, S.; Dittus, F.; Djama, F.; Djobava, T.; do Vale, M. A. B.; Do Valle Wemans, A.; Doan, T. K. O.; Dobbs, M.; Dobinson, R.; Dobos, D.; Dobson, E.; Dobson, M.; Dodd, J.; Doglioni, C.; Doherty, T.; Doi, Y.; Dolejsi, J.; Dolenc, I.; Dolezal, Z.; Dolgoshein, B. A.; Dohmae, T.; Donadelli, M.; Donega, M.; Donini, J.; Dopke, J.; Doria, A.; Dos Anjos, A.; Dosil, M.; Dotti, A.; Dova, M. T.; Dowell, J. D.; Doxiadis, A. D.; Doyle, A. T.; Drasal, Z.; Drees, J.; Dressnandt, N.; Drevermann, H.; Driouichi, C.; Dris, M.; Dubbert, J.; Dubbs, T.; Dube, S.; Duchovni, E.; Duckeck, G.; Dudarev, A.; Dudziak, F.; Dührssen, M.; Duerdoth, I. P.; Duflot, L.; Dufour, M.-A.; Dunford, M.; Yildiz, H. Duran; Duxfield, R.; Dwuznik, M.; Dydak, F.; Dzahini, D.; Düren, M.; Ebenstein, W. L.; Ebke, J.; Eckert, S.; Eckweiler, S.; Edmonds, K.; Edwards, C. A.; Edwards, N. C.; Ehrenfeld, W.; Ehrich, T.; Eifert, T.; Eigen, G.; Einsweiler, K.; Eisenhandler, E.; Ekelof, T.; El Kacimi, M.; Ellert, M.; Elles, S.; Ellinghaus, F.; Ellis, K.; Ellis, N.; Elmsheuser, J.; Elsing, M.; Ely, R.; Emeliyanov, D.; Engelmann, R.; Engl, A.; Epp, B.; Eppig, A.; Erdmann, J.; Ereditato, A.; Eriksson, D.; Ernst, J.; Ernst, M.; Ernwein, J.; Errede, D.; Errede, S.; Ertel, E.; Escalier, M.; Escobar, C.; Espinal Curull, X.; Esposito, B.; Etienne, F.; Etienvre, A. I.; Etzion, E.; Evangelakou, D.; Evans, H.; Fabbri, L.; Fabre, C.; Fakhrutdinov, R. M.; Falciano, S.; Fang, Y.; Fanti, M.; Farbin, A.; Farilla, A.; Farley, J.; Farooque, T.; Farrington, S. M.; Farthouat, P.; Fassnacht, P.; Fassouliotis, D.; Fatholahzadeh, B.; Favareto, A.; Fayard, L.; Fazio, S.; Febbraro, R.; Federic, P.; Fedin, O. L.; Fedorko, W.; Fehling-Kaschek, M.; Feligioni, L.; Fellmann, D.; Felzmann, C. U.; Feng, C.; Feng, E. J.; Fenyuk, A. B.; Ferencei, J.; Ferland, J.; Fernando, W.; Ferrag, S.; Ferrando, J.; Ferrara, V.; Ferrari, A.; Ferrari, P.; Ferrari, R.; Ferrer, A.; Ferrer, M. L.; Ferrere, D.; Ferretti, C.; Ferretto Parodi, A.; Fiascaris, M.; Fiedler, F.; Filipčič, A.; Filippas, A.; Filthaut, F.; Fincke-Keeler, M.; Fiolhais, M. C. N.; Fiorini, L.; Firan, A.; Fischer, G.; Fischer, P.; Fisher, M. J.; Fisher, S. M.; Flechl, M.; Fleck, I.; Fleckner, J.; Fleischmann, P.; Fleischmann, S.; Flick, T.; Flores Castillo, L. R.; Flowerdew, M. J.; Föhlisch, F.; Fokitis, M.; Martin, T. Fonseca; Forbush, D. A.; Formica, A.; Forti, A.; Fortin, D.; Foster, J. M.; Fournier, D.; Foussat, A.; Fowler, A. J.; Fowler, K.; Fox, H.; Francavilla, P.; Franchino, S.; Francis, D.; Frank, T.; Franklin, M.; Franz, S.; Fraternali, M.; Fratina, S.; French, S. T.; Froeschl, R.; Froidevaux, D.; Frost, J. A.; Fukunaga, C.; Fullana Torregrosa, E.; Fuster, J.; Gabaldon, C.; Gabizon, O.; Gadfort, T.; Gadomski, S.; Gagliardi, G.; Gagnon, P.; Galea, C.; Gallas, E. J.; Gallas, M. V.; Gallo, V.; Gallop, B. J.; Gallus, P.; Galyaev, E.; Gan, K. K.; Gao, Y. S.; Gapienko, V. A.; Gaponenko, A.; Garberson, F.; Garcia-Sciveres, M.; García, C.; Navarro, J. E. García; Gardner, R. W.; Garelli, N.; Garitaonandia, H.; Garonne, V.; Garvey, J.; Gatti, C.; Gaudio, G.; Gaumer, O.; Gaur, B.; Gauthier, L.; Gavrilenko, I. L.; Gay, C.; Gaycken, G.; Gayde, J.-C.; Gazis, E. N.; Ge, P.; Gee, C. N. P.; Geerts, D. A. A.; Geich-Gimbel, Ch.; Gellerstedt, K.; Gemme, C.; Gemmell, A.; Genest, M. H.; Gentile, S.; George, M.; George, S.; Gerlach, P.; Gershon, A.; Geweniger, C.; Ghazlane, H.; Ghez, P.; Ghodbane, N.; Giacobbe, B.; Giagu, S.; Giakoumopoulou, V.; Giangiobbe, V.; Gianotti, F.; Gibbard, B.; Gibson, A.; Gibson, S. M.; Gilbert, L. M.; Gilchriese, M.; Gilewsky, V.; Gillberg, D.; Gillman, A. R.; Gingrich, D. M.; Ginzburg, J.; Giokaris, N.; Giordano, R.; Giorgi, F. M.; Giovannini, P.; Giraud, P. F.; Giugni, D.; Giunta, M.; Giusti, P.; Gjelsten, B. K.; Gladilin, L. K.; Glasman, C.; Glatzer, J.; Glazov, A.; Glitza, K. W.; Glonti, G. L.; Godfrey, J.; Godlewski, J.; Goebel, M.; Göpfert, T.; Goeringer, C.; Gössling, C.; Göttfert, T.; Goldfarb, S.; Goldin, D.; Golling, T.; Golovnia, S. N.; Gomes, A.; Fajardo, L. S. Gomez; Gonçalo, R.; Goncalves Pinto Firmino Da Costa, J.; Gonella, L.; Gonidec, A.; Gonzalez, S.; González de la Hoz, S.; Silva, M. L. Gonzalez; Gonzalez-Sevilla, S.; Goodson, J. J.; Goossens, L.; Gorbounov, P. A.; Gordon, H. A.; Gorelov, I.; Gorfine, G.; Gorini, B.; Gorini, E.; Gorišek, A.; Gornicki, E.; Gorokhov, S. A.; Goryachev, V. N.; Gosdzik, B.; Gosselink, M.; Gostkin, M. I.; Gouanère, M.; Eschrich, I. Gough; Gouighri, M.; Goujdami, D.; Goulette, M. P.; Goussiou, A. G.; Goy, C.; Grabowska-Bold, I.; Grabski, V.; Grafström, P.; Grah, C.; Grahn, K.-J.; Grancagnolo, F.; Grancagnolo, S.; Grassi, V.; Gratchev, V.; Grau, N.; Gray, H. M.; Gray, J. A.; Graziani, E.; Grebenyuk, O. G.; Greenfield, D.; Greenshaw, T.; Greenwood, Z. D.; Gregor, I. M.; Grenier, P.; Griffiths, J.; Grigalashvili, N.; Grillo, A. A.; Grinstein, S.; Grishkevich, Y. V.; Grivaz, J.-F.; Grognuz, J.; Groh, M.; Gross, E.; Grosse-Knetter, J.; Groth-Jensen, J.; Grybel, K.; Guarino, V. J.; Guest, D.; Guicheney, C.; Guida, A.; Guillemin, T.; Guindon, S.; Guler, H.; Gunther, J.; Guo, B.; Guo, J.; Gupta, A.; Gusakov, Y.; Gushchin, V. N.; Gutierrez, A.; Gutierrez, P.; Guttman, N.; Gutzwiller, O.; Guyot, C.; Gwenlan, C.; Gwilliam, C. B.; Haas, A.; Haas, S.; Haber, C.; Hackenburg, R.; Hadavand, H. K.; Hadley, D. R.; Haefner, P.; Hahn, F.; Haider, S.; Hajduk, Z.; Hakobyan, H.; Haller, J.; Hamacher, K.; Hamal, P.; Hamilton, A.; Hamilton, S.; Han, H.; Han, L.; Hanagaki, K.; Hance, M.; Handel, C.; Hanke, P.; Hansen, J. R.; Hansen, J. B.; Hansen, J. D.; Hansen, P. H.; Hansson, P.; Hara, K.; Hare, G. A.; Harenberg, T.; Harkusha, S.; Harper, D.; Harrington, R. D.; Harris, O. M.; Harrison, K.; Hartert, J.; Hartjes, F.; Haruyama, T.; Harvey, A.; Hasegawa, S.; Hasegawa, Y.; Hassani, S.; Hatch, M.; Hauff, D.; Haug, S.; Hauschild, M.; Hauser, R.; Havranek, M.; Hawes, B. M.; Hawkes, C. M.; Hawkings, R. J.; Hawkins, D.; Hayakawa, T.; Hayden, D.; Hayward, H. S.; Haywood, S. J.; Hazen, E.; He, M.; Head, S. J.; Hedberg, V.; Heelan, L.; Heim, S.; Heinemann, B.; Heisterkamp, S.; Helary, L.; Heller, M.; Hellman, S.; Hellmich, D.; Helsens, C.; Henderson, R. C. W.; Henke, M.; Henrichs, A.; Correia, A. M. Henriques; Henrot-Versille, S.; Henry-Couannier, F.; Hensel, C.; Henß, T.; Hernandez, C. M.; Hernández Jiménez, Y.; Herrberg, R.; Hershenhorn, A. D.; Herten, G.; Hertenberger, R.; Hervas, L.; Hessey, N. P.; Hidvegi, A.; Higón-Rodriguez, E.; Hill, D.; Hill, J. C.; Hill, N.; Hiller, K. H.; Hillert, S.; Hillier, S. J.; Hinchliffe, I.; Hines, E.; Hirose, M.; Hirsch, F.; Hirschbuehl, D.; Hobbs, J.; Hod, N.; Hodgkinson, M. C.; Hodgson, P.; Hoecker, A.; Hoeferkamp, M. R.; Hoffman, J.; Hoffmann, D.; Hohlfeld, M.; Holder, M.; Holmes, A.; Holmgren, S. O.; Holy, T.; Holzbauer, J. L.; Homma, Y.; Hong, T. M.; Hooft van Huysduynen, L.; Horazdovsky, T.; Horn, C.; Horner, S.; Horton, K.; Hostachy, J.-Y.; Hou, S.; Houlden, M. A.; Hoummada, A.; Howarth, J.; Howell, D. F.; Hristova, I.; Hrivnac, J.; Hruska, I.; Hryn'ova, T.; Hsu, P. J.; Hsu, S.-C.; Huang, G. S.; Hubacek, Z.; Hubaut, F.; Huegging, F.; Huffman, T. B.; Hughes, E. W.; Hughes, G.; Hughes-Jones, R. E.; Huhtinen, M.; Hurst, P.; Hurwitz, M.; Husemann, U.; Huseynov, N.; Huston, J.; Huth, J.; Iacobucci, G.; Iakovidis, G.; Ibbotson, M.; Ibragimov, I.; Ichimiya, R.; Iconomidou-Fayard, L.; Idarraga, J.; Idzik, M.; Iengo, P.; Igonkina, O.; Ikegami, Y.; Ikeno, M.; Ilchenko, Y.; Iliadis, D.; Imbault, D.; Imhaeuser, M.; Imori, M.; Ince, T.; Inigo-Golfin, J.; Ioannou, P.; Iodice, M.; Ionescu, G.; Irles Quiles, A.; Ishii, K.; Ishikawa, A.; Ishino, M.; Ishmukhametov, R.; Issever, C.; Istin, S.; Itoh, Y.; Ivashin, A. V.; Iwanski, W.; Iwasaki, H.; Izen, J. M.; Izzo, V.; Jackson, B.; Jackson, J. N.; Jackson, P.; Jaekel, M. R.; Jain, V.; Jakobs, K.; Jakobsen, S.; Jakubek, J.; Jana, D. K.; Jankowski, E.; Jansen, E.; Jantsch, A.; Janus, M.; Jarlskog, G.; Jeanty, L.; Jelen, K.; Jen-La Plante, I.; Jenni, P.; Jeremie, A.; Jež, P.; Jézéquel, S.; Jha, M. K.; Ji, H.; Ji, W.; Jia, J.; Jiang, Y.; Belenguer, M. Jimenez; Jin, G.; Jin, S.; Jinnouchi, O.; Joergensen, M. D.; Joffe, D.; Johansen, L. G.; Johansen, M.; Johansson, K. E.; Johansson, P.; Johnert, S.; Johns, K. A.; Jon-And, K.; Jones, G.; Jones, R. W. L.; Jones, T. W.; Jones, T. J.; Jonsson, O.; Joram, C.; Jorge, P. M.; Joseph, J.; Jovin, T.; Ju, X.; Juranek, V.; Jussel, P.; Kabachenko, V. V.; Kabana, S.; Kaci, M.; Kaczmarska, A.; Kadlecik, P.; Kado, M.; Kagan, H.; Kagan, M.; Kaiser, S.; Kajomovitz, E.; Kalinin, S.; Kalinovskaya, L. V.; Kama, S.; Kanaya, N.; Kaneda, M.; Kanno, T.; Kantserov, V. A.; Kanzaki, J.; Kaplan, B.; Kapliy, A.; Kaplon, J.; Kar, D.; Karagoz, M.; Karnevskiy, M.; Karr, K.; Kartvelishvili, V.; Karyukhin, A. N.; Kashif, L.; Kasmi, A.; Kass, R. D.; Kastanas, A.; Kataoka, M.; Kataoka, Y.; Katsoufis, E.; Katzy, J.; Kaushik, V.; Kawagoe, K.; Kawamoto, T.; Kawamura, G.; Kayl, M. S.; Kazanin, V. A.; Kazarinov, M. Y.; Keates, J. R.; Keeler, R.; Kehoe, R.; Keil, M.; Kekelidze, G. D.; Kelly, M.; Kennedy, J.; Kenney, C. J.; Kenyon, M.; Kepka, O.; Kerschen, N.; Kerševan, B. P.; Kersten, S.; Kessoku, K.; Ketterer, C.; Keung, J.; Khakzad, M.; Khalil-zada, F.; Khandanyan, H.; Khanov, A.; Kharchenko, D.; Khodinov, A.; Kholodenko, A. G.; Khomich, A.; Khoo, T. J.; Khoriauli, G.; Khoroshilov, A.; Khovanskiy, N.; Khovanskiy, V.; Khramov, E.; Khubua, J.; Kim, H.; Kim, M. S.; Kim, P. C.; Kim, S. H.; Kimura, N.; Kind, O.; King, B. T.; King, M.; King, R. S. B.; Kirk, J.; Kirsch, G. P.; Kirsch, L. E.; Kiryunin, A. E.; Kisielewska, D.; Kittelmann, T.; Kiver, A. M.; Kiyamura, H.; Kladiva, E.; Klaiber-Lodewigs, J.; Klein, M.; Klein, U.; Kleinknecht, K.; Klemetti, M.; Klier, A.; Klimentov, A.; Klingenberg, R.; Klinkby, E. B.; Klioutchnikova, T.; Klok, P. F.; Klous, S.; Kluge, E.-E.; Kluge, T.; Kluit, P.; Kluth, S.; Kneringer, E.; Knobloch, J.; Knoops, E. B. F. G.; Knue, A.; Ko, B. R.; Kobayashi, T.; Kobel, M.; Kocian, M.; Kocnar, A.; Kodys, P.; Köneke, K.; König, A. C.; Koenig, S.; Köpke, L.; Koetsveld, F.; Koevesarki, P.; Koffas, T.; Koffeman, E.; Kohn, F.; Kohout, Z.; Kohriki, T.; Koi, T.; Kokott, T.; Kolachev, G. M.; Kolanoski, H.; Kolesnikov, V.; Koletsou, I.; Koll, J.; Kollar, D.; Kollefrath, M.; Kolya, S. D.; Komar, A. A.; Komaragiri, J. R.; Komori, Y.; Kondo, T.; Kono, T.; Kononov, A. I.; Konoplich, R.; Konstantinidis, N.; Kootz, A.; Koperny, S.; Kopikov, S. V.; Korcyl, K.; Kordas, K.; Koreshev, V.; Korn, A.; Korol, A.; Korolkov, I.; Korolkova, E. V.; Korotkov, V. A.; Kortner, O.; Kortner, S.; Kostyukhin, V. V.; Kotamäki, M. J.; Kotov, S.; Kotov, V. M.; Kotwal, A.; Kourkoumelis, C.; Kouskoura, V.; Koutsman, A.; Kowalewski, R.; Kowalski, T. Z.; Kozanecki, W.; Kozhin, A. S.; Kral, V.; Kramarenko, V. A.; Kramberger, G.; Krasel, O.; Krasny, M. W.; Krasznahorkay, A.; Kraus, J.; Kreisel, A.; Krejci, F.; Kretzschmar, J.; Krieger, N.; Krieger, P.; Kroeninger, K.; Kroha, H.; Kroll, J.; Kroseberg, J.; Krstic, J.; Kruchonak, U.; Krüger, H.; Kruker, T.; Krumshteyn, Z. V.; Kruth, A.; Kubota, T.; Kuehn, S.; Kugel, A.; Kuhl, T.; Kuhn, D.; Kukhtin, V.; Kulchitsky, Y.; Kuleshov, S.; Kummer, C.; Kuna, M.; Kundu, N.; Kunkle, J.; Kupco, A.; Kurashige, H.; Kurata, M.; Kurochkin, Y. A.; Kus, V.; Kuykendall, W.; Kuze, M.; Kuzhir, P.; Kvasnicka, O.; Kvita, J.; Kwee, R.; La Rosa, A.; La Rotonda, L.; Labarga, L.; Labbe, J.; Lablak, S.; Lacasta, C.; Lacava, F.; Lacker, H.; Lacour, D.; Lacuesta, V. R.; Ladygin, E.; Lafaye, R.; Laforge, B.; Lagouri, T.; Lai, S.; Laisne, E.; Lamanna, M.; Lampen, C. L.; Lampl, W.; Lancon, E.; Landgraf, U.; Landon, M. P. J.; Landsman, H.; Lane, J. L.; Lange, C.; Lankford, A. J.; Lanni, F.; Lantzsch, K.; Laplace, S.; Lapoire, C.; Laporte, J. F.; Lari, T.; Larionov, A. V.; Larner, A.; Lasseur, C.; Lassnig, M.; Lau, W.; Laurelli, P.; Lavorato, A.; Lavrijsen, W.; Laycock, P.; Lazarev, A. B.; Lazzaro, A.; Le Dortz, O.; Le Guirriec, E.; Le Maner, C.; Le Menedeu, E.; Lebel, C.; LeCompte, T.; Ledroit-Guillon, F.; Lee, H.; Lee, J. S. H.; Lee, S. C.; Lee, L.; Lefebvre, M.; Legendre, M.; Leger, A.; LeGeyt, B. C.; Legger, F.; Leggett, C.; Lehmacher, M.; Lehmann Miotto, G.; Lei, X.; Leite, M. A. L.; Leitner, R.; Lellouch, D.; Lellouch, J.; Leltchouk, M.; Lendermann, V.; Leney, K. J. C.; Lenz, T.; Lenzen, G.; Lenzi, B.; Leonhardt, K.; Leontsinis, S.; Leroy, C.; Lessard, J.-R.; Lesser, J.; Lester, C. G.; Leung Fook Cheong, A.; Levêque, J.; Levin, D.; Levinson, L. J.; Levitski, M. S.; Lewandowska, M.; Lewis, A.; Lewis, G. H.; Leyko, A. M.; Leyton, M.; Li, B.; Li, H.; Li, S.; Li, X.; Liang, Z.; Liang, Z.; Liberti, B.; Lichard, P.; Lichtnecker, M.; Lie, K.; Liebig, W.; Lifshitz, R.; Lilley, J. N.; Limbach, C.; Limosani, A.; Limper, M.; Lin, S. C.; Linde, F.; Linnemann, J. T.; Lipeles, E.; Lipinsky, L.; Lipniacka, A.; Liss, T. M.; Lissauer, D.; Lister, A.; Litke, A. M.; Liu, C.; Liu, D.; Liu, H.; Liu, J. B.; Liu, M.; Liu, S.; Liu, Y.; Livan, M.; Livermore, S. S. A.; Lleres, A.; Llorente Merino, J.; Lloyd, S. L.; Lobodzinska, E.; Loch, P.; Lockman, W. S.; Lockwitz, S.; Loddenkoetter, T.; Loebinger, F. K.; Loginov, A.; Loh, C. W.; Lohse, T.; Lohwasser, K.; Lokajicek, M.; Loken, J.; Lombardo, V. P.; Long, R. E.; Lopes, L.; Lopez Mateos, D.; Losada, M.; Loscutoff, P.; Sterzo, F. Lo; Losty, M. J.; Lou, X.; Lounis, A.; Loureiro, K. F.; Love, J.; Love, P. A.; Lowe, A. J.; Lu, F.; Lubatti, H. J.; Luci, C.; Lucotte, A.; Ludwig, A.; Ludwig, D.; Ludwig, I.; Ludwig, J.; Luehring, F.; Luijckx, G.; Lumb, D.; Luminari, L.; Lund, E.; Lund-Jensen, B.; Lundberg, B.; Lundberg, J.; Lundquist, J.; Lungwitz, M.; Lupi, A.; Lutz, G.; Lynn, D.; Lys, J.; Lytken, E.; Ma, H.; Ma, L. L.; Macana Goia, J. A.; Maccarrone, G.; Macchiolo, A.; Maček, B.; Miguens, J. Machado; Macina, D.; Mackeprang, R.; Madaras, R. J.; Mader, W. F.; Maenner, R.; Maeno, T.; Mättig, P.; Mättig, S.; Magalhaes Martins, P. J.; Magnoni, L.; Magradze, E.; Mahalalel, Y.; Mahboubi, K.; Mahout, G.; Maiani, C.; Maidantchik, C.; Maio, A.; Majewski, S.; Makida, Y.; Makovec, N.; Mal, P.; Malecki, Pa.; Malecki, P.; Maleev, V. P.; Malek, F.; Mallik, U.; Malon, D.; Maltezos, S.; Malyshev, V.; Malyukov, S.; Mameghani, R.; Mamuzic, J.; Manabe, A.; Mandelli, L.; Mandić, I.; Mandrysch, R.; Maneira, J.; Mangeard, P. S.; Manjavidze, I. D.; Mann, A.; Manning, P. M.; Manousakis-Katsikakis, A.; Mansoulie, B.; Manz, A.; Mapelli, A.; Mapelli, L.; March, L.; Marchand, J. F.; Marchese, F.; Marchiori, G.; Marcisovsky, M.; Marin, A.; Marino, C. P.; Marroquim, F.; Marshall, R.; Marshall, Z.; Martens, F. K.; Marti-Garcia, S.; Martin, A. J.; Martin, B.; Martin, B.; Martin, F. F.; Martin, J. P.; Martin, Ph.; Martin, T. A.; dit Latour, B. Martin; Martinez, M.; Outschoorn, V. Martinez; Martyniuk, A. C.; Marx, M.; Marzano, F.; Marzin, A.; Masetti, L.; Mashimo, T.; Mashinistov, R.; Masik, J.; Maslennikov, A. L.; Maß, M.; Massa, I.; Massaro, G.; Massol, N.; Mastrandrea, P.; Mastroberardino, A.; Masubuchi, T.; Mathes, M.; Matricon, P.; Matsumoto, H.; Matsunaga, H.; Matsushita, T.; Mattravers, C.; Maugain, J. M.; Maxfield, S. J.; Maximov, D. A.; May, E. N.; Mayne, A.; Mazini, R.; Mazur, M.; Mazzanti, M.; Mazzoni, E.; Mc Kee, S. P.; McCarn, A.; McCarthy, R. L.; McCarthy, T. G.; McCubbin, N. A.; McFarlane, K. W.; Mcfayden, J. A.; McGlone, H.; Mchedlidze, G.; McLaren, R. A.; Mclaughlan, T.; McMahon, S. J.; McPherson, R. A.; Meade, A.; Mechnich, J.; Mechtel, M.; Medinnis, M.; Meera-Lebbai, R.; Meguro, T.; Mehdiyev, R.; Mehlhase, S.; Mehta, A.; Meier, K.; Meinhardt, J.; Meirose, B.; Melachrinos, C.; Mellado Garcia, B. R.; Mendoza Navas, L.; Meng, Z.; Mengarelli, A.; Menke, S.; Menot, C.; Meoni, E.; Mercurio, K. M.; Mermod, P.; Merola, L.; Meroni, C.; Merritt, F. S.; Messina, A.; Metcalfe, J.; Mete, A. S.; Meuser, S.; Meyer, C.; Meyer, J.-P.; Meyer, J.; Meyer, J.; Meyer, T. C.; Meyer, W. T.; Miao, J.; Michal, S.; Micu, L.; Middleton, R. P.; Miele, P.; Migas, S.; Mijović, L.; Mikenberg, G.; Mikestikova, M.; Mikuž, M.; Miller, D. W.; Miller, R. J.; Mills, W. J.; Mills, C.; Milov, A.; Milstead, D. A.; Milstein, D.; Minaenko, A. A.; Miñano, M.; Minashvili, I. A.; Mincer, A. I.; Mindur, B.; Mineev, M.; Ming, Y.; Mir, L. M.; Mirabelli, G.; Miralles Verge, L.; Misiejuk, A.; Mitrevski, J.; Mitrofanov, G. Y.; Mitsou, V. A.; Mitsui, S.; Miyagawa, P. S.; Miyazaki, K.; Mjörnmark, J. U.; Moa, T.; Mockett, P.; Moed, S.; Moeller, V.; Mönig, K.; Möser, N.; Mohapatra, S.; Mohn, B.; Mohr, W.; Mohrdieck-Möck, S.; Moisseev, A. M.; Moles-Valls, R.; Molina-Perez, J.; Monk, J.; Monnier, E.; Montesano, S.; Monticelli, F.; Monzani, S.; Moore, R. W.; Moorhead, G. F.; Herrera, C. Mora; Moraes, A.; Morais, A.; Morange, N.; Morel, J.; Morello, G.; Moreno, D.; Llácer, M. Moreno; Morettini, P.; Morii, M.; Morin, J.; Morita, Y.; Morley, A. K.; Mornacchi, G.; Morone, M.-C.; Morozov, S. V.; Morris, J. D.; Morvaj, L.; Moser, H. G.; Mosidze, M.; Moss, J.; Mount, R.; Mountricha, E.; Mouraviev, S. V.; Moyse, E. J. W.; Mudrinic, M.; Mueller, F.; Mueller, J.; Mueller, K.; Müller, T. A.; Muenstermann, D.; Muijs, A.; Muir, A.; Munwes, Y.; Murakami, K.; Murray, W. J.; Mussche, I.; Musto, E.; Myagkov, A. G.; Myska, M.; Nadal, J.; Nagai, K.; Nagano, K.; Nagasaka, Y.; Nairz, A. M.; Nakahama, Y.; Nakamura, K.; Nakano, I.; Nanava, G.; Napier, A.; Nash, M.; Nation, N. R.; Nattermann, T.; Naumann, T.; Navarro, G.; Neal, H. A.; Nebot, E.; Nechaeva, P. Yu.; Negri, A.; Negri, G.; Nektarijevic, S.; Nelson, A.; Nelson, S.; Nelson, T. K.; Nemecek, S.; Nemethy, P.; Nepomuceno, A. A.; Nessi, M.; Nesterov, S. Y.; Neubauer, M. S.; Neusiedl, A.; Neves, R. M.; Nevski, P.; Newman, P. R.; Nickerson, R. B.; Nicolaidou, R.; Nicolas, L.; Nicquevert, B.; Niedercorn, F.; Nielsen, J.; Niinikoski, T.; Nikiforov, A.; Nikolaenko, V.; Nikolaev, K.; Nikolic-Audit, I.; Nikolics, K.; Nikolopoulos, K.; Nilsen, H.; Nilsson, P.; Ninomiya, Y.; Nisati, A.; Nishiyama, T.; Nisius, R.; Nodulman, L.; Nomachi, M.; Nomidis, I.; Nordberg, M.; Nordkvist, B.; Norton, P. R.; Novakova, J.; Nozaki, M.; Nožička, M.; Nozka, L.; Nugent, I. M.; Nuncio-Quiroz, A.-E.; Nunes Hanninger, G.; Nunnemann, T.; Nurse, E.; Nyman, T.; O'Brien, B. J.; O'Neale, S. W.; O'Neil, D. C.; O'Shea, V.; Oakham, F. G.; Oberlack, H.; Ocariz, J.; Ochi, A.; Oda, S.; Odaka, S.; Odier, J.; Ogren, H.; Oh, A.; Oh, S. H.; Ohm, C. C.; Ohshima, T.; Ohshita, H.; Ohska, T. K.; Ohsugi, T.; Okada, S.; Okawa, H.; Okumura, Y.; Okuyama, T.; Olcese, M.; Olchevski, A. G.; Oliveira, M.; Damazio, D. Oliveira; Garcia, E. Oliver; Olivito, D.; Olszewski, A.; Olszowska, J.; Omachi, C.; Onofre, A.; Onyisi, P. U. E.; Oram, C. J.; Oreglia, M. J.; Oren, Y.; Orestano, D.; Orlov, I.; Oropeza Barrera, C.; Orr, R. S.; Osculati, B.; Ospanov, R.; Osuna, C.; y Garzon, G. Otero; Ottersbach, J. P.; Ouchrif, M.; Ould-Saada, F.; Ouraou, A.; Ouyang, Q.; Owen, M.; Owen, S.; Øye, O. K.; Ozcan, V. E.; Ozturk, N.; Pacheco Pages, A.; Padilla Aranda, C.; Griso, S. Pagan; Paganis, E.; Paige, F.; Pajchel, K.; Palestini, S.; Pallin, D.; Palma, A.; Palmer, J. D.; Pan, Y. B.; Panagiotopoulou, E.; Panes, B.; Panikashvili, N.; Panitkin, S.; Pantea, D.; Panuskova, M.; Paolone, V.; Papadelis, A.; Papadopoulou, Th. D.; Paramonov, A.; Park, W.; Parker, M. A.; Parodi, F.; Parsons, J. A.; Parzefall, U.; Pasqualucci, E.; Passeri, A.; Pastore, F.; Pastore, Fr.; Pásztor, G.; Pataraia, S.; Patel, N.; Pater, J. R.; Patricelli, S.; Pauly, T.; Pecsy, M.; Pedraza Morales, M. I.; Peleganchuk, S. V.; Peng, H.; Pengo, R.; Penson, A.; Penwell, J.; Perantoni, M.; Perez, K.; Cavalcanti, T. Perez; Codina, E. Perez; Pérez García-Estañ, M. T.; Reale, V. Perez; Perini, L.; Pernegger, H.; Perrino, R.; Perrodo, P.; Persembe, S.; Peshekhonov, V. D.; Peters, O.; Petersen, B. A.; Petersen, J.; Petersen, T. C.; Petit, E.; Petridis, A.; Petridou, C.; Petrolo, E.; Petrucci, F.; Petschull, D.; Petteni, M.; Pezoa, R.; Phan, A.; Phillips, A. W.; Phillips, P. W.; Piacquadio, G.; Piccaro, E.; Piccinini, M.; Pickford, A.; Piec, S. M.; Piegaia, R.; Pilcher, J. E.; Pilkington, A. D.; Pina, J.; Pinamonti, M.; Pinder, A.; Pinfold, J. L.; Ping, J.; Pinto, B.; Pirotte, O.; Pizio, C.; Placakyte, R.; Plamondon, M.; Plano, W. G.; Pleier, M.-A.; Pleskach, A. V.; Poblaguev, A.; Poddar, S.; Podlyski, F.; Poggioli, L.; Poghosyan, T.; Pohl, M.; Polci, F.; Polesello, G.; Policicchio, A.; Polini, A.; Poll, J.; Polychronakos, V.; Pomarede, D. M.; Pomeroy, D.; Pommès, K.; Pontecorvo, L.; Pope, B. G.; Popeneciu, G. A.; Popovic, D. S.; Poppleton, A.; Portell Bueso, X.; Porter, R.; Posch, C.; Pospelov, G. E.; Pospisil, S.; Potrap, I. N.; Potter, C. J.; Potter, C. T.; Poulard, G.; Poveda, J.; Prabhu, R.; Pralavorio, P.; Prasad, S.; Pravahan, R.; Prell, S.; Pretzl, K.; Pribyl, L.; Price, D.; Price, L. E.; Price, M. J.; Prichard, P. M.; Prieur, D.; Primavera, M.; Prokofiev, K.; Prokoshin, F.; Protopopescu, S.; Proudfoot, J.; Prudent, X.; Przysiezniak, H.; Psoroulas, S.; Ptacek, E.; Purdham, J.; Purohit, M.; Puzo, P.; Pylypchenko, Y.; Qian, J.; Qian, Z.; Qin, Z.; Quadt, A.; Quarrie, D. R.; Quayle, W. B.; Quinonez, F.; Raas, M.; Radescu, V.; Radics, B.; Rador, T.; Ragusa, F.; Rahal, G.; Rahimi, A. M.; Rahm, D.; Rajagopalan, S.; Rammensee, M.; Rammes, M.; Ramstedt, M.; Randrianarivony, K.; Ratoff, P. N.; Rauscher, F.; Rauter, E.; Raymond, M.; Read, A. L.; Rebuzzi, D. M.; Redelbach, A.; Redlinger, G.; Reece, R.; Reeves, K.; Reichold, A.; Reinherz-Aronis, E.; Reinsch, A.; Reisinger, I.; Reljic, D.; Rembser, C.; Ren, Z. L.; Renaud, A.; Renkel, P.; Rescigno, M.; Resconi, S.; Resende, B.; Reznicek, P.; Rezvani, R.; Richards, A.; Richter, R.; Richter-Was, E.; Ridel, M.; Rieke, S.; Rijpstra, M.; Rijssenbeek, M.; Rimoldi, A.; Rinaldi, L.; Rios, R. R.; Riu, I.; Rivoltella, G.; Rizatdinova, F.; Rizvi, E.; Robertson, S. H.; Robichaud-Veronneau, A.; Robinson, D.; Robinson, J. E. M.; Robinson, M.; Robson, A.; Rocha de Lima, J. G.; Roda, C.; Dos Santos, D. Roda; Rodier, S.; Rodriguez, D.; Garcia, Y. Rodriguez; Roe, A.; Roe, S.; Røhne, O.; Rojo, V.; Rolli, S.; Romaniouk, A.; Romanov, V. M.; Romeo, G.; Romero Maltrana, D.; Roos, L.; Ros, E.; Rosati, S.; Rosbach, K.; Rose, M.; Rosenbaum, G. A.; Rosenberg, E. I.; Rosendahl, P. L.; Rosselet, L.; Rossetti, V.; Rossi, E.; Rossi, L. P.; Rossi, L.; Rotaru, M.; Roth, I.; Rothberg, J.; Rousseau, D.; Royon, C. R.; Rozanov, A.; Rozen, Y.; Ruan, X.; Rubinskiy, I.; Ruckert, B.; Ruckstuhl, N.; Rud, V. I.; Rudolph, C.; Rudolph, G.; Rühr, F.; Ruggieri, F.; Ruiz-Martinez, A.; Rulikowska-Zarebska, E.; Rumiantsev, V.; Rumyantsev, L.; Runge, K.; Runolfsson, O.; Rurikova, Z.; Rusakovich, N. A.; Rust, D. R.; Rutherfoord, J. P.; Ruwiedel, C.; Ruzicka, P.; Ryabov, Y. F.; Ryadovikov, V.; Ryan, P.; Rybar, M.; Rybkin, G.; Ryder, N. C.; Rzaeva, S.; Saavedra, A. F.; Sadeh, I.; Sadrozinski, H. F.-W.; Sadykov, R.; Safai Tehrani, F.; Sakamoto, H.; Salamanna, G.; Salamon, A.; Saleem, M.; Salihagic, D.; Salnikov, A.; Salt, J.; Salvachua Ferrando, B. M.; Salvatore, D.; Salvatore, F.; Salvucci, A.; Salzburger, A.; Sampsonidis, D.; Samset, B. H.; Sanchez, A.; Sandaker, H.; Sander, H. G.; Sanders, M. P.; Sandhoff, M.; Sandoval, T.; Sandstroem, R.; Sandvoss, S.; Sankey, D. P. C.; Sansoni, A.; Santamarina Rios, C.; Santoni, C.; Santonico, R.; Santos, H.; Saraiva, J. G.; Sarangi, T.; Sarkisyan-Grinbaum, E.; Sarri, F.; Sartisohn, G.; Sasaki, O.; Sasaki, T.; Sasao, N.; Satsounkevitch, I.; Sauvage, G.; Sauvan, E.; Sauvan, J. B.; Savard, P.; Savinov, V.; Savu, D. O.; Savva, P.; Sawyer, L.; Saxon, D. H.; Says, L. P.; Sbarra, C.; Sbrizzi, A.; Scallon, O.; Scannicchio, D. A.; Schaarschmidt, J.; Schacht, P.; Schäfer, U.; Schaepe, S.; Schaetzel, S.; Schaffer, A. C.; Schaile, D.; Schamberger, R. D.; Schamov, A. G.; Scharf, V.; Schegelsky, V. A.; Scheirich, D.; Scherzer, M. I.; Schiavi, C.; Schieck, J.; Schioppa, M.; Schlenker, S.; Schlereth, J. L.; Schmidt, E.; Schmieden, K.; Schmitt, C.; Schmitt, S.; Schmitz, M.; Schöning, A.; Schott, M.; Schouten, D.; Schovancova, J.; Schram, M.; Schroeder, C.; Schroer, N.; Schuh, S.; Schuler, G.; Schultes, J.; Schultz-Coulon, H.-C.; Schulz, H.; Schumacher, J. W.; Schumacher, M.; Schumm, B. A.; Schune, Ph.; Schwanenberger, C.; Schwartzman, A.; Schwemling, Ph.; Schwienhorst, R.; Schwierz, R.; Schwindling, J.; Schwindt, T.; Scott, W. G.; Searcy, J.; Sedykh, E.; Segura, E.; Seidel, S. C.; Seiden, A.; Seifert, F.; Seixas, J. M.; Sekhniaidze, G.; Seliverstov, D. M.; Sellden, B.; Sellers, G.; Seman, M.; Semprini-Cesari, N.; Serfon, C.; Serin, L.; Seuster, R.; Severini, H.; Sevior, M. E.; Sfyrla, A.; Shabalina, E.; Shamim, M.; Shan, L. Y.; Shank, J. T.; Shao, Q. T.; Shapiro, M.; Shatalov, P. B.; Shaver, L.; Shaw, C.; Shaw, K.; Sherman, D.; Sherwood, P.; Shibata, A.; Shichi, H.; Shimizu, S.; Shimojima, M.; Shin, T.; Shmeleva, A.; Shochet, M. J.; Short, D.; Shupe, M. A.; Sicho, P.; Sidoti, A.; Siebel, A.; Siegert, F.; Siegrist, J.; Sijacki, Dj.; Silbert, O.; Silva, J.; Silver, Y.; Silverstein, D.; Silverstein, S. B.; Simak, V.; Simard, O.; Simic, Lj.; Simion, S.; Simmons, B.; Simonyan, M.; Sinervo, P.; Sinev, N. B.; Sipica, V.; Siragusa, G.; Sisakyan, A. N.; Sivoklokov, S. Yu.; Sjölin, J.; Sjursen, T. B.; Skinnari, L. A.; Skovpen, K.; Skubic, P.; Skvorodnev, N.; Slater, M.; Slavicek, T.; Sliwa, K.; Sloan, T. J.; Sloper, J.; Smakhtin, V.; Smirnov, S. Yu.; Smirnova, L. N.; Smirnova, O.; Smith, B. C.; Smith, D.; Smith, K. M.; Smizanska, M.; Smolek, K.; Snesarev, A. A.; Snow, S. W.; Snow, J.; Snuverink, J.; Snyder, S.; Soares, M.; Sobie, R.; Sodomka, J.; Soffer, A.; Solans, C. A.; Solar, M.; Solc, J.; Soldatov, E.; Soldevila, U.; Solfaroli Camillocci, E.; Solodkov, A. A.; Solovyanov, O. V.; Sondericker, J.; Soni, N.; Sopko, V.; Sopko, B.; Sorbi, M.; Sosebee, M.; Soukharev, A.; Spagnolo, S.; Spanò, F.; Spighi, R.; Spigo, G.; Spila, F.; Spiriti, E.; Spiwoks, R.; Spousta, M.; Spreitzer, T.; Spurlock, B.; Denis, R. D. St.; Stahl, T.; Stahlman, J.; Stamen, R.; Stanecka, E.; Stanek, R. W.; Stanescu, C.; Stapnes, S.; Starchenko, E. A.; Stark, J.; Staroba, P.; Starovoitov, P.; Staude, A.; Stavina, P.; Stavropoulos, G.; Steele, G.; Steinbach, P.; Steinberg, P.; Stekl, I.; Stelzer, B.; Stelzer, H. J.; Stelzer-Chilton, O.; Stenzel, H.; Stevenson, K.; Stewart, G. A.; Stillings, J. A.; Stockmanns, T.; Stockton, M. C.; Stoerig, K.; Stoicea, G.; Stonjek, S.; Strachota, P.; Stradling, A. R.; Straessner, A.; Strandberg, J.; Strandberg, S.; Strandlie, A.; Strang, M.; Strauss, E.; Strauss, M.; Strizenec, P.; Ströhmer, R.; Strom, D. M.; Strong, J. A.; Stroynowski, R.; Strube, J.; Stugu, B.; Stumer, I.; Stupak, J.; Sturm, P.; Soh, D. A.; Su, D.; Subramania, H. S.; Succurro, A.; Sugaya, Y.; Sugimoto, T.; Suhr, C.; Suita, K.; Suk, M.; Sulin, V. V.; Sultansoy, S.; Sumida, T.; Sun, X.; Sundermann, J. E.; Suruliz, K.; Sushkov, S.; Susinno, G.; Sutton, M. R.; Suzuki, Y.; Svatos, M.; Sviridov, Yu. M.; Swedish, S.; Sykora, I.; Sykora, T.; Szeless, B.; Sánchez, J.; Ta, D.; Tackmann, K.; Taffard, A.; Tafirout, R.; Taga, A.; Taiblum, N.; Takahashi, Y.; Takai, H.; Takashima, R.; Takeda, H.; Takeshita, T.; Talby, M.; Talyshev, A.; Tamsett, M. C.; Tanaka, J.; Tanaka, R.; Tanaka, S.; Tanaka, S.; Tanaka, Y.; Tani, K.; Tannoury, N.; Tappern, G. P.; Tapprogge, S.; Tardif, D.; Tarem, S.; Tarrade, F.; Tartarelli, G. F.; Tas, P.; Tasevsky, M.; Tassi, E.; Tatarkhanov, M.; Taylor, C.; Taylor, F. E.; Taylor, G. N.; Taylor, W.; Castanheira, M. Teixeira Dias; Teixeira-Dias, P.; Temming, K. K.; Ten Kate, H.; Teng, P. K.; Terada, S.; Terashi, K.; Terron, J.; Terwort, M.; Testa, M.; Teuscher, R. J.; Thadome, J.; Therhaag, J.; Theveneaux-Pelzer, T.; Thioye, M.; Thoma, S.; Thomas, J. P.; Thompson, E. N.; Thompson, P. D.; Thompson, P. D.; Thompson, A. S.; Thomson, E.; Thomson, M.; Thun, R. P.; Tic, T.; Tikhomirov, V. O.; Tikhonov, Y. A.; Timmermans, C. J. W. P.; Tipton, P.; Tique Aires Viegas, F. J.; Tisserant, S.; Tobias, J.; Toczek, B.; Todorov, T.; Todorova-Nova, S.; Toggerson, B.; Tojo, J.; Tokár, S.; Tokunaga, K.; Tokushuku, K.; Tollefson, K.; Tomoto, M.; Tompkins, L.; Toms, K.; Tong, G.; Tonoyan, A.; Topfel, C.; Topilin, N. D.; Torchiani, I.; Torrence, E.; Torres, H.; Torró Pastor, E.; Toth, J.; Touchard, F.; Tovey, D. R.; Traynor, D.; Trefzger, T.; Tremblet, L.; Tricoli, A.; Trigger, I. M.; Trincaz-Duvoid, S.; Trinh, T. N.; Tripiana, M. F.; Trischuk, W.; Trivedi, A.; Trocmé, B.; Troncon, C.; Trottier-McDonald, M.; Trzupek, A.; Tsarouchas, C.; Tseng, J. C.-L.; Tsiakiris, M.; Tsiareshka, P. V.; Tsionou, D.; Tsipolitis, G.; Tsiskaridze, V.; Tskhadadze, E. G.; Tsukerman, I. I.; Tsulaia, V.; Tsung, J.-W.; Tsuno, S.; Tsybychev, D.; Tua, A.; Tuggle, J. M.; Turala, M.; Turecek, D.; Turk Cakir, I.; Turlay, E.; Turra, R.; Tuts, P. M.; Tykhonov, A.; Tylmad, M.; Tyndel, M.; Tyrvainen, H.; Tzanakos, G.; Uchida, K.; Ueda, I.; Ueno, R.; Ugland, M.; Uhlenbrock, M.; Uhrmacher, M.; Ukegawa, F.; Unal, G.; Underwood, D. G.; Undrus, A.; Unel, G.; Unno, Y.; Urbaniec, D.; Urkovsky, E.; Urrejola, P.; Usai, G.; Uslenghi, M.; Vacavant, L.; Vacek, V.; Vachon, B.; Vahsen, S.; Valenta, J.; Valente, P.; Valentinetti, S.; Valkar, S.; Valladolid Gallego, E.; Vallecorsa, S.; Valls Ferrer, J. A.; van der Graaf, H.; van der Kraaij, E.; Van Der Leeuw, R.; van der Poel, E.; van der Ster, D.; Van Eijk, B.; van Eldik, N.; van Gemmeren, P.; van Kesteren, Z.; van Vulpen, I.; Vandelli, W.; Vandoni, G.; Vaniachine, A.; Vankov, P.; Vannucci, F.; Varela Rodriguez, F.; Vari, R.; Varnes, E. W.; Varouchas, D.; Vartapetian, A.; Varvell, K. E.; Vassilakopoulos, V. I.; Vazeille, F.; Vegni, G.; Veillet, J. J.; Vellidis, C.; Veloso, F.; Veness, R.; Veneziano, S.; Ventura, A.; Ventura, D.; Venturi, M.; Venturi, N.; Vercesi, V.; Verducci, M.; Verkerke, W.; Vermeulen, J. C.; Vest, A.; Vetterli, M. C.; Vichou, I.; Vickey, T.; Viehhauser, G. H. A.; Viel, S.; Villa, M.; Villaplana Perez, M.; Vilucchi, E.; Vincter, M. G.; Vinek, E.; Vinogradov, V. B.; Virchaux, M.; Virzi, J.; Vitells, O.; Viti, M.; Vivarelli, I.; Vives Vaque, F.; Vlachos, S.; Vlasak, M.; Vlasov, N.; Vogel, A.; Vokac, P.; Volpi, G.; Volpi, M.; Volpini, G.; von der Schmitt, H.; von Loeben, J.; von Radziewski, H.; von Toerne, E.; Vorobel, V.; Vorobiev, A. P.; Vorwerk, V.; Vos, M.; Voss, R.; Voss, T. T.; Vossebeld, J. H.; Vranjes, N.; Vranjes Milosavljevic, M.; Vrba, V.; Vreeswijk, M.; Anh, T. Vu; Vuillermet, R.; Vukotic, I.; Wagner, W.; Wagner, P.; Wahlen, H.; Wakabayashi, J.; Walbersloh, J.; Walch, S.; Walder, J.; Walker, R.; Walkowiak, W.; Wall, R.; Waller, P.; Wang, C.; Wang, H.; Wang, H.; Wang, J.; Wang, J.; Wang, J. C.; Wang, R.; Wang, S. M.; Warburton, A.; Ward, C. P.; Warsinsky, M.; Watkins, P. M.; Watson, A. T.; Watson, M. F.; Watts, G.; Watts, S.; Waugh, A. T.; Waugh, B. M.; Weber, J.; Weber, M.; Weber, M. S.; Weber, P.; Weidberg, A. R.; Weigell, P.; Weingarten, J.; Weiser, C.; Wellenstein, H.; Wells, P. S.; Wen, M.; Wenaus, T.; Wendler, S.; Weng, Z.; Wengler, T.; Wenig, S.; Wermes, N.; Werner, M.; Werner, P.; Werth, M.; Wessels, M.; Weydert, C.; Whalen, K.; Wheeler-Ellis, S. J.; Whitaker, S. P.; White, A.; White, M. J.; White, S.; Whitehead, S. R.; Whiteson, D.; Whittington, D.; Wicek, F.; Wicke, D.; Wickens, F. J.; Wiedenmann, W.; Wielers, M.; Wienemann, P.; Wiglesworth, C.; Wiik, L. A. M.; Wijeratne, P. A.; Wildauer, A.; Wildt, M. A.; Wilhelm, I.; Wilkens, H. G.; Will, J. Z.; Williams, E.; Williams, H. H.; Willis, W.; Willocq, S.; Wilson, J. A.; Wilson, M. G.; Wilson, A.; Wingerter-Seez, I.; Winkelmann, S.; Winklmeier, F.; Wittgen, M.; Wolter, M. W.; Wolters, H.; Wooden, G.; Wosiek, B. K.; Wotschack, J.; Woudstra, M. J.; Wraight, K.; Wright, C.; Wrona, B.; Wu, S. L.; Wu, X.; Wu, Y.; Wulf, E.; Wunstorf, R.; Wynne, B. M.; Xaplanteris, L.; Xella, S.; Xie, S.; Xie, Y.; Xu, C.; Xu, D.; Xu, G.; Yabsley, B.; Yamada, M.; Yamamoto, A.; Yamamoto, K.; Yamamoto, S.; Yamamura, T.; Yamaoka, J.; Yamazaki, T.; Yamazaki, Y.; Yan, Z.; Yang, H.; Yang, U. K.; Yang, Y.; Yang, Y.; Yang, Z.; Yanush, S.; Yao, W.-M.; Yao, Y.; Yasu, Y.; Ybeles Smit, G. V.; Ye, J.; Ye, S.; Yilmaz, M.; Yoosoofmiya, R.; Yorita, K.; Yoshida, R.; Young, C.; Youssef, S.; Yu, D.; Yu, J.; Yu, J.; Yuan, L.; Yurkewicz, A.; Zaets, V. G.; Zaidan, R.; Zaitsev, A. M.; Zajacova, Z.; Zalite, Yo. K.; Zanello, L.; Zarzhitsky, P.; Zaytsev, A.; Zeitnitz, C.; Zeller, M.; Zemla, A.; Zendler, C.; Zenin, A. V.; Zenin, O.; Ženiš, T.; Zenonos, Z.; Zenz, S.; Zerwas, D.; della Porta, G. Zevi; Zhan, Z.; Zhang, D.; Zhang, H.; Zhang, J.; Zhang, X.; Zhang, Z.; Zhao, L.; Zhao, T.; Zhao, Z.; Zhemchugov, A.; Zheng, S.; Zhong, J.; Zhou, B.; Zhou, N.; Zhou, Y.; Zhu, C. G.; Zhu, H.; Zhu, J.; Zhu, Y.; Zhuang, X.; Zhuravlov, V.; Zieminska, D.; Zimmermann, R.; Zimmermann, S.; Zimmermann, S.; Ziolkowski, M.; Zitoun, R.; Živković, L.; Zmouchko, V. V.; Zobernig, G.; Zoccoli, A.; Zolnierowski, Y.; Zsenei, A.; zur Nedden, M.; Zutshi, V.; Zwalinski, L.

2011-10-01

Making use of 36 pb-1 of proton-proton collision data at sqrt{s} =7 TeV, the ATLAS Collaboration has performed a search for diphoton events with large missing transverse energy. Observing no excess of events above the Standard Model prediction, a 95% Confidence Level (CL) upper limit is set on the cross section for new physics of σ<0.38-0.65 pb in the context of a generalised model of gauge-mediated supersymmetry breaking (GGM) with a bino-like lightest neutralino, and of σ<0.18-0.23 pb in the context of a specific model with one universal extra dimension (UED). A 95% CL lower limit of 560 GeV, for bino masses above 50 GeV, is set on the GGM gluino mass, while a lower limit of 1/ R>961 GeV is set on the UED compactification radius R. These limits provide the most stringent tests of these models to date.

Search for squarks and gluinos in events with isolated leptons, jets and missing transverse momentum at $$\\sqrt{s}=8 $$ TeV with the ATLAS detector

DOE PAGES

Aad, G.; Abbott, B.; Abdallah, J.; ...

2015-04-21

The results of a search for supersymmetry in final states containing at least one isolated lepton (electron or muon), jets and large missing transverse momentum with the ATLAS detector at the Large Hadron Collider are reported. The search is based on proton-proton collision data at a centre-of-mass energy √ = 8 TeV collected in 2012, corresponding to an integrated luminosity of 20 fb -1. No significant excess above the Standard Model expectation is observed. Limits are set on supersymmetric particle masses for various supersymmetric models. Depending on the model, the search excludes gluino masses up to 1.32 TeV and squarkmore » masses up to 840 GeV. Limits are also set on the parameters of a minimal universal extra dimension model, excluding a compactification radius of 1/R c = 950 GeV for a cut-off scale times radius (ΛR c) of approximately 30.« less

On geometric classification of 5d SCFTs

NASA Astrophysics Data System (ADS)

Jefferson, Patrick; Katz, Sheldon; Kim, Hee-Cheol; Vafa, Cumrun

2018-04-01

We formulate geometric conditions necessary for engineering 5d superconformal field theories (SCFTs) via M-theory compactification on a local Calabi-Yau 3-fold. Extending the classification of the rank 1 cases, which are realized geometrically as shrinking del Pezzo surfaces embedded in a 3-fold, we propose an exhaustive classification of local 3-folds engineering rank 2 SCFTs in 5d. This systematic classification confirms that all rank 2 SCFTs predicted using gauge theoretic arguments can be realized as consistent theories, with the exception of one family which is shown to be non-perturbatively inconsistent and thereby ruled out by geometric considerations. We find that all rank 2 SCFTs descend from 6d (1,0) SCFTs compactified on a circle possibly twisted with an automorphism together with holonomies for global symmetries around the Kaluza-Klein circle. These results support our conjecture that every 5d SCFT can be obtained from the circle compactification of some parent 6d (1,0) SCFT.

Phenomenological implications of the blown-up orbifolds

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cvetic, M.

1987-05-01

We discuss the structure of the effective Lagrangian for the (2,2) Z/sub N/ orbifolds and the corresponding Calabi-Yau manifolds which are obtained by ''blowing-up'' the orbifold singularities. The method to ''blow-up'' such singularities is reviewed. Results are exact at the string tree-level. In particular, the question of generating an intermediate scale M/sub I/ in such models is addressed. It is shown that for Z/sub N/ orbifolds (except one) and the corresponding blown-up orbifolds which are compactified on any six-torus T/sup 6/ which can be obtained by continuously deforming T/sup 4/ circle times T/sup 2/, all the terms of the typemore » (2727)/sup K/ are absent from the effective superpotential, thus questioning the mechanism for generating a large intermediate scale for such compactifications.« less

(0,2) elephants

NASA Astrophysics Data System (ADS)

Aspinwall, Paul S.; Melnikov, Ilarion V.; Plesser, M. Ronen

2012-01-01

We enumerate massless E6 singlets for (0,2)-compactifications of the heterotic string on a Calabi-Yau threefold with the "standard embedding" in three distinct ways. In the large radius limit of the threefold, these singlets count deformations of the Calabi-Yau together with its tangent bundle. In the "small-radius" limit we apply Landau-Ginzburg methods. In the orbifold limit we use a combination of geometry and free field methods. In general these counts differ. We show how to identify states between these phases and how certain states vanish from the massless spectrum as one deforms the complex structure or Kähler form away from the Gepner point. The appearance of extra singlets for particular values of complex structure is explored in all three pictures, and our results suggest that this does not depend on the Kähler moduli.

Fermion dark matter in gauge-Higgs unification

DOE PAGES

Maru, Nobuhito; Miyaji, Takashi; Okada, Nobuchika; ...

2017-07-11

Here, we propose a Majorana fermion dark matter in the context of a s imple gauge-Higgs Unification (GHU) scenario based on the gauge group SU(3)×U(1)' in 5-dimensional Minkowski space with a compactification of the 5th dimension on S 1/Z 2 orbifold. The dark matter particle is identified with the lightest mode in SU(3) triplet fermions additionally introduced in the 5-dimensional bulk. We find an allowed parameter region for the dark matter mass around a half of the Standard Model Higgs boson mass, which is consistent with the observed dark matter density and the constraint from the LUX 2016 result formore » the direct dark matter search. The entire allowed region will be covered by, for example, the LUX-ZEPLIN dark matter experiment in the near future. We also show that in the presence of the bulk SU(3) triplet fermions the 125 GeV Higgs boson mas s is reproduced through the renormalization group evolution of Higgs quartic coupling with the compactification scale of around 10 8 GeV.« less

Foliated eight-manifolds for M-theory compactification

NASA Astrophysics Data System (ADS)

Babalic, Elena Mirela; Lazaroiu, Calin Iuliu

2015-01-01

We characterize compact eight-manifolds M which arise as internal spaces in flux compactifications of M-theory down to AdS3 using the theory of foliations, for the case when the internal part ξ of the supersymmetry generator is everywhere non-chiral. We prove that specifying such a supersymmetric background is equivalent with giving a codimension one foliation of M which carries a leafwise G 2 structure, such that the O'Neill-Gray tensors, non-adapted part of the normal connection and the torsion classes of the G 2 structure are given in terms of the supergravity four-form field strength by explicit formulas which we derive. We discuss the topology of such foliations, showing that the C * algebra is a noncommutative torus of dimension given by the irrationality rank of a certain cohomology class constructed from G, which must satisfy the Latour obstruction. We also give a criterion in terms of this class for when such foliations are fibrations over the circle. When the criterion is not satisfied, each leaf of is dense in M.

Non-perturbative effects and wall-crossing from topological strings

NASA Astrophysics Data System (ADS)

Collinucci, Andrés; Soler, Pablo; Uranga, Angel M.

2009-11-01

We argue that the Gopakumar-Vafa interpretation of the topological string partition function can be used to compute and resum certain non-perturbative brane instanton effects of type II CY compactifications. In particular the topological string A-model encodes the non-perturbative corrections to the hypermultiplet moduli space metric from general D1/D(-1)-brane instantons in 4d Script N = 2 IIB models. We also discuss the reduction to 4d Script N = 1 by fluxes and/or orientifolds and/or D-branes, and the prospects to resum brane instanton contributions to non-perturbative superpotentials. We argue that the connection between non-perturbative effects and the topological string underlies the continuity of non-perturbative effects across lines of BPS stability. We also confirm this statement in mirror B-model matrix model examples, relating matrix model instantons to non-perturbative D-brane instantons. The computation of non-perturbative effects from the topological string requires a 3d circle compactification and T-duality, relating effects from particles and instantons, reminiscent of that involved in the physical derivation of the Kontsevich-Soibelmann wall-crossing formula.

Search for diphoton events with large missing transverse energy with 36 pb –1 of 7 TeV proton–proton collision data with the ATLAS detector

DOE PAGES

Aad, G.; Abbott, B.; Abdallah, J.; ...

2011-10-05

Making use of 36 pb –1 of proton–proton collision data at √s = 7 TeV, the ATLAS Collaboration has performed a search for diphoton events with large missing transverse energy. Observing no excess of events above the Standard Model prediction, a 95% Confidence Level (CL) upper limit is set on the cross section for new physics of σ<0.38–0.65 pb in the context of a generalised model of gauge-mediated supersymmetry breaking (GGM) with a bino-like lightest neutralino, and of σ<0.18–0.23 pb in the context of a specific model with one universal extra dimension (UED). A 95% CL lower limit of 560more » GeV, for bino masses above 50 GeV, is set on the GGM gluino mass, while a lower limit of 1/ R>961 GeV is set on the UED compactification radius R. In conclusion, these limits provide the most stringent tests of these models to date.« less

Deconfinement in Yang-Mills Theory through Toroidal Compactification

DOE Office of Scientific and Technical Information (OSTI.GOV)

Simic, Dusan; Unsal, Mithat; /Stanford U., Phys. Dept. /SLAC

2011-08-12

We introduce field theory techniques through which the deconfinement transition of four-dimensional Yang-Mills theory can be moved to a semi-classical domain where it becomes calculable using two-dimensional field theory. We achieve this through a double-trace deformation of toroidally compactified Yang-Mills theory on R{sup 2} x S{sub L}{sup 1} x S{sub {beta}}{sup 1}. At large N, fixed-L, and arbitrary {beta}, the thermodynamics of the deformed theory is equivalent to that of ordinary Yang-Mills theory at leading order in the large N expansion. At fixed-N, small L and a range of {beta}, the deformed theory maps to a two-dimensional theory with electricmore » and magnetic (order and disorder) perturbations, analogs of which appear in planar spin-systems and statistical physics. We show that in this regime the deconfinement transition is driven by the competition between electric and magnetic perturbations in this two-dimensional theory. This appears to support the scenario proposed by Liao and Shuryak regarding the magnetic component of the quark-gluon plasma at RHIC.« less

Flavor structure in F-theory compactifications

NASA Astrophysics Data System (ADS)

Hayashi, Hirotaka; Kawano, Teruhiko; Tsuchiya, Yoichi; Watari, Taizan

2010-08-01

F-theory is one of frameworks in string theory where supersymmetric grand unification is accommodated, and all the Yukawa couplings and Majorana masses of righthanded neutrinos are generated. Yukawa couplings of charged fermions are generated at codimension-3 singularities, and a contribution from a given singularity point is known to be approximately rank 1. Thus, the approximate rank of Yukawa matrices in low-energy effective theory of generic F-theory compactifications are minimum of either the number of generations N gen = 3 or the number of singularity points of certain types. If there is a geometry with only one E 6 type point and one D 6 type point over the entire 7-brane for SU(5) gauge fields, F-theory compactified on such a geometry would reproduce approximately rank-1 Yukawa matrices in the real world. We found, however, that there is no such geometry. Thus, it is a problem how to generate hierarchical Yukawa eigenvalues in F-theory compactifications. A solution in the literature so far is to take an appropriate factorization limit. In this article, we propose an alternative solution to the hierarchical structure problem (which requires to tune some parameters) by studying how zero mode wavefunctions depend on complex structure moduli. In this solution, the N gen × N gen CKM matrix is predicted to have only N gen entries of order unity without an extra tuning of parameters, and the lepton flavor anarchy is predicted for the lepton mixing matrix. The hierarchy among the Yukawa eigenvalues of the down-type and charged lepton sector is predicted to be smaller than that of the up-type sector, and the Majorana masses of left-handed neutrinos generated through the see-saw mechanism have small hierarchy. All of these predictions agree with what we observe in the real world. We also obtained a precise description of zero mode wavefunctions near the E 6 type singularity points, where the up-type Yukawa couplings are generated.

Instanton operators and symmetry enhancement in 5d supersymmetric quiver gauge theories

NASA Astrophysics Data System (ADS)

Yonekura, Kazuya

2015-07-01

We consider general 5d SU( N ) quiver gauge theories whose nodes form an ADE Dynkin diagram of type G. Each node has SU( N i ) gauge group of general rank, Chern-Simons level κ i and additional w i fundamentals. When the total flavor number at each node is less than or equal to 2 N i - 2| κ i |, we give general rules under which the symmetries associated to instanton currents are enhanced to G × G or a subgroup of it in the UV 5d superconformal theory. When the total flavor number violates that condition at some of the nodes, further enhancement of flavor symmetries occurs. In particular we find a large class of gauge theories interpreted as S 1 compactification of 6d superconformal theories which are waiting for string/F-theory realization. We also consider hypermultiplets in (anti-)symmetric representation.

Cosmological moduli and the post-inflationary universe: A critical review

NASA Astrophysics Data System (ADS)

Kane, Gordon; Sinha, Kuver; Watson, Scott

2015-06-01

We critically review the role of cosmological moduli in determining the post-inflationary history of the universe. Moduli are ubiquitous in string and M-theory constructions of beyond the Standard Model physics, where they parametrize the geometry of the compactification manifold. For those with masses determined by supersymmetry (SUSY) breaking this leads to their eventual decay slightly before Big Bang nucleosynthesis (BBN) (without spoiling its predictions). This results in a matter dominated phase shortly after inflation ends, which can influence baryon and dark matter genesis, as well as observations of the cosmic microwave background (CMB) and the growth of large-scale structure. Given progress within fundamental theory, and guidance from dark matter and collider experiments, nonthermal histories have emerged as a robust and theoretically well-motivated alternative to a strictly thermal one. We review this approach to the early universe and discuss both the theoretical challenges and the observational implications.

Is inflation from unwinding fluxes IIB?

NASA Astrophysics Data System (ADS)

Gautason, Fridrik Freyr; Schillo, Marjorie; Van Riet, Thomas

2017-03-01

In this paper we argue that the mechanism of unwinding inflation is naturally present in warped compactifications of type IIB string theory with local throats. The unwinding of flux is caused by its annihilation against branes. The resulting inflaton potential is linear with periodic modulations. We initiate an analysis of the inflationary dynamics and cosmological observables, which are highly constrained by moduli stabilization. For the simplified model of single-Kähler Calabi-Yau spaces we find that many, though not all of the consistency constraints can be satisfied. Particularly, in this simple model geometric constraints are in tension with obtaining the observed amplitude of the scalar power spectrum. However, we do find 60 efolds of inflation with a trans-Planckian field excursion which offers the hope that slightly more complicated models can lead to a fully consistent explicit construction of large field inflation of this kind.

Nonperturbative corrections to 4D string theory effective actions from SL(2,Z) duality and supersymmetry.

PubMed

Robles-Llana, Daniel; Rocek, Martin; Saueressig, Frank; Theis, Ulrich; Vandoren, Stefan

2007-05-25

We find the D(-1)- and D1-brane instanton contributions to the hypermultiplet moduli space of type IIB string compactifications on Calabi-Yau threefolds. These combine with known perturbative and world sheet instanton corrections into a single modular invariant function that determines the hypermultiplet low-energy effective action.

A black hole quartet: New solutions and applications to string theory

NASA Astrophysics Data System (ADS)

Padi, Megha

In this thesis, we study a zoo of black hole solutions which help us connect string theory to the universe we live in. The intuition for how to attack fundamental problems can often be found in a toy model. In Chapter 2, we show that three-dimensional topologically massive gravity with a negative cosmological constant -ℓ -2 and coupling constant has "warped AdS3" solutions with SL(2, R ) x U(1) isometry. For muℓ > 3, we show that certain discrete quotients of warped AdS3 lead to black holes. Their thermodynamics is consistent with the existence of a holographic dual CFT with central charges cR = 15mℓ 2+81Gmm ℓ2+27 and cL = 12mℓ 2Gmm ℓ2+27 . The entropy of many supersymmetric black holes have been accounted for, but more realistic non-supersymmetric black holes have been largely overlooked. In Chapter 3, we derive new single-centered and multi-centered non-BPS black hole solutions for several four dimensional models which, after Kaluza-Klein reduction, admit a description in terms of a sigma model with symmetric target space. In particular, we provide the exact solution with generic charges and asymptotic moduli in N=2 supergravity coupled to one vector multiplet. As it stands, the current formulation of string theory allows for an extremely large number of possible solutions (or vacua). We first analyze this landscape by looking for universal characteristics. In Chapter 4, we provide evidence for the conjecture that gravity is always the weakest force in any string compactification. We show that, in several examples arising in string theory, higher-derivative corrections always make extremal non-supersymmetric black holes lighter than the classical bound M/Q = 1. In Chapter 5, we construct novel black hole bound states, called orientiholes, that are T-dual to IIB orientifold compactifications. The gravitational entropy of such orientiholes provides an "experimental" estimate of the number of vacua in various sectors of the IIB landscape. Furthermore, basic physical properties of orientiholes map to (sometimes subtle) microscopic features, thus providing a useful alternative viewpoint on a number of issues arising in D-brane model building. We also suggest a relation to the topological string analogous to the OSV conjecture.

p-brane actions and higher Roytenberg brackets

NASA Astrophysics Data System (ADS)

Jurčo, Branislav; Schupp, Peter; Vysoký, Jan

2013-02-01

Motivated by the quest to understand the analog of non-geometric flux compactification in the context of M-theory, we study higher dimensional analogs of generalized Poisson sigma models and corresponding dual string and p-brane models. We find that higher generalizations of the algebraic structures due to Dorfman, Roytenberg and Courant play an important role and establish their relation to Nambu-Poisson structures.

Non-geometric fluxes, quasi-Hopf twist deformations, and nonassociative quantum mechanics

NASA Astrophysics Data System (ADS)

Mylonas, Dionysios; Schupp, Peter; Szabo, Richard J.

2014-12-01

We analyse the symmetries underlying nonassociative deformations of geometry in non-geometric R-flux compactifications which arise via T-duality from closed strings with constant geometric fluxes. Starting from the non-abelian Lie algebra of translations and Bopp shifts in phase space, together with a suitable cochain twist, we construct the quasi-Hopf algebra of symmetries that deforms the algebra of functions and the exterior differential calculus in the phase space description of nonassociative R-space. In this setting, nonassociativity is characterised by the associator 3-cocycle which controls non-coassociativity of the quasi-Hopf algebra. We use abelian 2-cocycle twists to construct maps between the dynamical nonassociative star product and a family of associative star products parametrized by constant momentum surfaces in phase space. We define a suitable integration on these nonassociative spaces and find that the usual cyclicity of associative noncommutative deformations is replaced by weaker notions of 2-cyclicity and 3-cyclicity. Using this star product quantization on phase space together with 3-cyclicity, we formulate a consistent version of nonassociative quantum mechanics, in which we calculate the expectation values of area and volume operators, and find coarse-graining of the string background due to the R-flux.

Confusing the heterotic string

NASA Astrophysics Data System (ADS)

Benett, D.; Brene, N.; Mizrachi, Leah; Nielsen, H. B.

1986-10-01

A confusion mechanism is proposed as a global modification of the heterotic string model. It envolves a confusion hypersurface across which the two E 8's of the heterotic string are permuted. A remarkable numerical coincidence is found which prevents an inconsistency in the model. The low energy limit of this theory (after compactification) is typically invariant under one E 8 only, thereby removing the shadow world from the original model.

Gravity waves and the LHC: towards high-scale inflation with low-energy SUSY

NASA Astrophysics Data System (ADS)

He, Temple; Kachru, Shamit; Westphal, Alexander

2010-06-01

It has been argued that rather generic features of string-inspired inflationary theories with low-energy supersymmetry (SUSY) make it difficult to achieve inflation with a Hubble scale H > m 3/2, where m 3/2 is the gravitino mass in the SUSY-breaking vacuum state. We present a class of string-inspired supergravity realizations of chaotic inflation where a simple, dynamical mechanism yields hierarchically small scales of post-inflationary supersymmetry breaking. Within these toy models we can easily achieve small ratios between m 3/2 and the Hubble scale of inflation. This is possible because the expectation value of the superpotential < W> relaxes from large to small values during the course of inflation. However, our toy models do not provide a reasonable fit to cosmological data if one sets the SUSY-breaking scale to m 3/2 ≤ TeV. Our work is a small step towards relieving the apparent tension between high-scale inflation and low-scale supersymmetry breaking in string compactifications.

Higher derivative couplings in theories with sixteen supersymmetries

DOE PAGES

Lin, Ying -Hsuan; Shao, Shu -Heng; Yin, Xi; ...

2015-12-15

We give simple arguments for new non-renormalization theorems on higher derivative couplings of gauge theories to supergravity, with sixteen supersymmetries, by considerations of brane-bulk superamplitudes. This leads to some exact results on the effective coupling of D3-branes in type IIB string theory. As a result, we also derive exact results on higher dimensional operators in the torus compactification of the six dimensional (0, 2) superconformal theory.

Compactifications of deformed conifolds, branes and the geometry of qubits

NASA Astrophysics Data System (ADS)

Cvetič, M.; Gibbons, G. W.; Pope, C. N.

2016-01-01

We present three families of exact, cohomogeneity-one Einstein metrics in (2 n + 2) dimensions, which are generalizations of the Stenzel construction of Ricci-flat metrics to those with a positive cosmological constant. The first family of solutions are Fubini-Study metrics on the complex projective spaces C{P}^{n+1} , written in a Stenzel form, whose principal orbits are the Stiefel manifolds {V}_2(R}^{n+2})=SO(n+2)/SO(n) divided by {Z}_2 . The second family are also Einstein-Kähler metrics, now on the Grassmannian manifolds {G}_2({{R}}^{n+3})=SO(n+3)/((SO(n+1)× SO(2)), whose principal orbits are the Stiefel manifolds {V}_2({{R}}^{n+2}) (with no {{Z}}_2 factoring in this case). The third family are Einstein metrics on the product manifolds S n+1 × S n+1, and are Kähler only for n = 1. Some of these metrics are believed to play a role in studies of consistent string theory compactifications and in the context of the AdS/CFT correspondence. We also elaborate on the geometric approach to quantum mechanics based on the Kähler geometry of Fubini-Study metrics on {C}{{P}}^{n+1} , and we apply the formalism to study the quantum entanglement of qubits.

Compactifications of deformed conifolds, branes and the geometry of qubits $\\mathfrak S

DOE PAGES

Cvetič, M.; Gibbons, G. W.; Pope, C. N.

2016-01-22

We present three families of exact, cohomogeneity-one Einstein metrics in (2n + 2) dimensions, which are generalizations of the Stenzel construction of Ricci-flat metrics to those with a positive cosmological constant. The first family of solutions are Fubini-Study metrics on the complex projective spaces CP n+1, written in a Stenzel form, whose principal orbits are the Stiefel manifolds V 2(more » $$\\mathbb R^{2+3}$$) = SO(n+2)/SO(n) divided by Z 2. The second family are also Einstein-Kahler metrics, now on the Grassmannian manifolds G 2(R n+3) = SO(n+3)/((SO(n+1)×SO(2)), whose principal orbits are the Stiefel manifolds V 2($$\\mathbb R^{2+3}$$) (with no Z 2 factoring in this case). Furthermore, the third family are Einstein metrics on the product manifolds S n+1 × S n+1, and are Kahler only for n = 1. Some of these metrics are believed to play a role in studies of consistent string theory compactifications and in the context of the AdS/CFT correspondence. Also, we elaborate on the geometric approach to quantum mechanics based on the Kahler geometry of Fubini-Study metrics on $$\\mathbb CP^{n+1}$$, and we apply the formalism to study the quantum entanglement of qubits.« less

Theory and phenomenology of Planckian interacting massive particles as dark matter

NASA Astrophysics Data System (ADS)

Garny, Mathias; Palessandro, Andrea; Sandora, McCullen; Sloth, Martin S.

2018-02-01

Planckian Interacting Dark Matter (PIDM) is a minimal scenario of dark matter assuming only gravitational interactions with the standard model and with only one free parameter, the PIDM mass. PIDM can be successfully produced by gravitational scattering in the thermal plasma of the Standard Model sector after inflation in the PIDM mass range from TeV up to the GUT scale, if the reheating temperature is sufficiently high. The minimal assumption of a GUT scale PIDM mass can be tested in the future by measurements of the primordial tensor-to-scalar ratio. While large primordial tensor modes would be in tension with the QCD axion as dark matter in a large mass range, it would favour the PIDM as a minimal alternative to WIMPs. Here we generalise the previously studied scalar PIDM scenario to the case of fermion, vector and tensor PIDM scenarios, and show that the phenomenology is nearly identical, independent of the spin of the PIDM. We also consider the specific realisation of the PIDM as the Kaluza-Klein excitation of the graviton in orbifold compactifications of string theory, as well as in models of monodromy inflation and in Higgs inflation. Finally we discuss the possibility of indirect detection of PIDM through non-perturbative decay.

Search for diphoton events with large missing transverse momentum in 1 fb(-1) of 7 TeV proton-proton collision data with the ATLAS detector

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aad G.; Abbott B.; Abdallah J.

2012-04-20

A search for diphoton events with large missing transverse momentum has been performed using 1.07 fb{sup -1} of proton-proton collision data at {radical}s = 7 TeV recorded with the ATLAS detector. No excess of events was observed above the Standard Model prediction and 95% Confidence Level (CL) upper limits are set on the production cross section for new physics. The limits depend on each model parameter space and vary as follows: {sigma} < (22-129) fb in the context of a generalized model of gauge-mediated supersymmetry breaking (GGM) with a bino-like lightest neutralino, {sigma} < (27-91) fb in the context ofmore » a minimal model of gauge-mediated supersymmetry breaking (SPS8), and {sigma} < (15-27) fb in the context of a specific model with one universal extra dimension (UED). A 95% CL lower limit of 805 GeV, for bino masses above 50 GeV, is set on the GGM gluino mass. Lower limits of 145 TeV and 1.23 TeV are set on the SPS8 breaking scale {Lambda} and on the UED compactification scale 1/R, respectively. These limits provide the most stringent tests of these models to date.« less

Search for diphoton events with large missing transverse momentum in 1 fb - 1 of 7 TeV proton–proton collision data with the ATLAS detector

DOE PAGES

Aad, G.; Abbott, B.; Abdallah, J.; ...

2012-02-22

A search for diphoton events with large missing transverse momentum has been performed using 1.07fb -1 of proton–proton collision data at s=7TeV recorded with the ATLAS detector. No excess of events was observed above the Standard Model prediction and 95% Confidence Level (CL) upper limits are set on the production cross section for new physics. The limits depend on each model parameter space and vary as follows: σ<(22–129)fb in the context of a generalised model of gauge-mediated supersymmetry breaking (GGM) with a bino-like lightest neutralino, σ<(27–91)fb in the context of a minimal model of gauge-mediated supersymmetry breaking (SPS8), and σ<(15–27)fbmore » in the context of a specific model with one universal extra dimension (UED). A 95% CL lower limit of 805GeV, for bino masses above 50 GeV, is set on the GGM gluino mass. Lower limits of 145TeV and 1.23TeV are set on the SPS8 breaking scale Λ and on the UED compactification scale 1/R, respectively. These limits provide the most stringent tests of these models to date.« less

Adventures in heterotic string phenomenology

NASA Astrophysics Data System (ADS)

Dundee, George Benjamin

In this Dissertation, we consider three topics in the study of effective field theories derived from orbifold compactifications of the heterotic string. In Chapter 2 we provide a primer for those interested in building models based on orbifold compactifications of the heterotic string. In Chapter 3, we analyze gauge coupling unification in the context of heterotic strings on anisotropic orbifolds. This construction is very much analogous to effective five dimensional orbifold GUT field theories. Our analysis assumes three fundamental scales, the string scale, M S, a compactification scale, MC, and a mass scale for some of the vector-like exotics, MEX; the other exotics are assumed to get mass at MS. In the particular models analyzed, we show that gauge coupling unification is not possible with MEX = M C and in fact we require MEX << MC ˜ 3 x 1016 GeV. We find that about 10% of the parameter space has a proton lifetime (from dimension six gauge exchange) 1033 yr ≲ tau(p → pi0e+) ≲ 1036 yr, which is potentially observable by the next generation of proton decay experiments. 80% of the parameter space gives proton lifetimes below Super-K bounds. In Chapter 4, we examine the relationship between the string coupling constant, gSTRING, and the grand unified gauge coupling constant, alphaGUT, in the models of Chapter 3. We find that the requirement that the theory be perturbative provides a non-trivial constraint on these models. Interestingly, there is a correlation between the proton decay rate (due to dimension six operators) and the string coupling constant in this class of models. Finally, we make some comments concerning the extension of these models to the six (and higher) dimensional case. In Chapter 5, we discuss the issues of supersymmetry breaking and moduli stabilization within the context of E8 ⊗ E8 heterotic orbifold constructions and, in particular, we focus on the class of "mini-landscape" models. These theories contain a non-Abelian hidden gauge sector which generates a non-perturbative superpotential leading to supersymmetry breaking and moduli stabilization. We demonstrate this effect in a simple model which contains many of the features of the more general construction. In addition, we argue that once supersymmetry is broken in a restricted sector of the theory, then all moduli are stabilized by supergravity effects. Finally, we obtain the low energy superparticle spectrum resulting from this simple model.

Entropy of N=2 black holes and their M-brane description

DOE Office of Scientific and Technical Information (OSTI.GOV)

Behrndt, K.; Mohaupt, T.

1997-08-01

In this paper we discuss the M-brane description for an N=2 black hole. This solution is a result of the compactification of M-5-brane configurations over a Calabi-Yau threefold with arbitrary intersection numbers C{sub ABC}. In analogy with the D-brane description where one counts open string states we count here open M-2-branes which end on the M-5-brane. {copyright} {ital 1997} {ital The American Physical Society}

Global D-brane models with stabilised moduli and light axions

NASA Astrophysics Data System (ADS)

Cicoli, Michele

2014-03-01

We review recent attempts to try to combine global issues of string compactifications, like moduli stabilisation, with local issues, like semi-realistic D-brane constructions. We list the main problems encountered, and outline a possible solution which allows globally consistent embeddings of chiral models. We also argue that this stabilisation mechanism leads to an axiverse. We finally illustrate our general claims in a concrete example where the Calabi-Yau manifold is explicitly described by toric geometry.

The F-theory geometry with most flux vacua

DOE PAGES

Taylor, Washington; Wang, Yi -Nan

2015-12-28

Applying the Ashok-Denef-Douglas estimation method to elliptic Calabi-Yau fourfolds suggests that a single elliptic fourfold M max gives rise to O(10 272,000) F-theory flux vacua, and that the sum total of the numbers of flux vacua from all other F-theory geometries is suppressed by a relative factor of O(10 –3000). The fourfold M max arises from a generic elliptic fibration over a specific toric threefold base B max, and gives a geometrically non-Higgsable gauge group of E 8 9 × F 4 8 × (G 2 × SU(2)) 16, of which we expect some factors to be broken by G-fluxmore » to smaller groups. It is not possible to tune an SU(5) GUT group on any further divisors in M max, or even an SU(2) or SU(3), so the standard model gauge group appears to arise in this context only from a broken E 8 factor. Furthermore, the results of this paper can either be interpreted as providing a framework for predicting how the standard model arises most naturally in F-theory and the types of dark matter to be found in a typical F-theory compactification, or as a challenge to string theorists to explain why other choices of vacua are not exponentially unlikely compared to F-theory compactifications on M max.« less

How well can we really determine the scale of inflation?

NASA Astrophysics Data System (ADS)

Özsoy, Ogan; Sinha, Kuver; Watson, Scott

2015-05-01

A detection of primordial B modes has been heralded not only as a smoking gun for the existence of inflation, but also as a way to establish the scale at which inflation took place. In this paper we critically reinvestigate the connection between a detection of primordial gravity waves and the scale of inflation. We consider whether the presence of additional fields and nonadiabaticity during inflation may have provided an additional source of primordial B modes competitive with those of the quasi-de Sitter vacuum. In particular, we examine whether the additional sources could provide the dominant signal, which could lead to a misinterpretation of the scale of inflation. In light of constraints on the level of non-Gaussianity coming from Planck we find that only hidden sectors with strictly gravitationally strong couplings provide a feasible mechanism. The required model building is somewhat elaborate, and so we discuss possible UV completions in the context of type IIB orientifold compactifications with Ramond-Ramond axions. We find that an embedding is possible and that dangerous sinusoidal corrections can be suppressed through the compactification geometry. Our main result is that even when additional sources of primordial gravity waves are competitive with the inflaton, a positive B-mode detection would still be a relatively good indicator of the scale of inflation. This conclusion will be strengthened by future constraints on both non-Gaussianity and cosmic microwave background polarization.

The F-theory geometry with most flux vacua

DOE Office of Scientific and Technical Information (OSTI.GOV)

Taylor, Washington; Wang, Yi -Nan

Applying the Ashok-Denef-Douglas estimation method to elliptic Calabi-Yau fourfolds suggests that a single elliptic fourfold M max gives rise to O(10 272,000) F-theory flux vacua, and that the sum total of the numbers of flux vacua from all other F-theory geometries is suppressed by a relative factor of O(10 –3000). The fourfold M max arises from a generic elliptic fibration over a specific toric threefold base B max, and gives a geometrically non-Higgsable gauge group of E 8 9 × F 4 8 × (G 2 × SU(2)) 16, of which we expect some factors to be broken by G-fluxmore » to smaller groups. It is not possible to tune an SU(5) GUT group on any further divisors in M max, or even an SU(2) or SU(3), so the standard model gauge group appears to arise in this context only from a broken E 8 factor. Furthermore, the results of this paper can either be interpreted as providing a framework for predicting how the standard model arises most naturally in F-theory and the types of dark matter to be found in a typical F-theory compactification, or as a challenge to string theorists to explain why other choices of vacua are not exponentially unlikely compared to F-theory compactifications on M max.« less

6D fractional quantum Hall effect

NASA Astrophysics Data System (ADS)

Heckman, Jonathan J.; Tizzano, Luigi

2018-05-01

We present a 6D generalization of the fractional quantum Hall effect involving membranes coupled to a three-form potential in the presence of a large background four-form flux. The low energy physics is governed by a bulk 7D topological field theory of abelian three-form potentials with a single derivative Chern-Simons-like action coupled to a 6D anti-chiral theory of Euclidean effective strings. We derive the fractional conductivity, and explain how continued fractions which figure prominently in the classification of 6D superconformal field theories correspond to a hierarchy of excited states. Using methods from conformal field theory we also compute the analog of the Laughlin wavefunction. Compactification of the 7D theory provides a uniform perspective on various lower-dimensional gapped systems coupled to boundary degrees of freedom. We also show that a supersymmetric version of the 7D theory embeds in M-theory, and can be decoupled from gravity. Encouraged by this, we present a conjecture in which IIB string theory is an edge mode of a 10 + 2-dimensional bulk topological theory, thus placing all twelve dimensions of F-theory on a physical footing.

Isolated Minkowski vacua, and stability analysis for an extended brane in the rugby ball

NASA Astrophysics Data System (ADS)

Himmetoǧlu, Burak; Peloso, Marco

2007-06-01

We study a recently proposed model, where a codimension one brane is wrapped around the axis of symmetry of an internal two-dimensional space compactified by a flux. This construction is free from the problems which plague delta-like, codimension two branes, where only tension can be present. In contrast, arbitrary fields can be localized on this extended brane, and their gravitational interaction is standard 4d gravity at large distances. In the first part of this work, we study the de Sitter (dS) vacua of the model. The landscape of these vacua is characterized by discrete points labeled by two integer numbers, related to the flux responsible for the compactification and to the current of a brane field. A Minkowski external space emerges only for a special ratio between these two integers, and it is therefore (topologically) isolated from the nearby dS solutions. In the second part, we show that the Minkowski vacua are stable under the most generic axially-symmetric perturbations, and we argue that this is sufficient to ensure the overall stability.

SU(6) GUT breaking on a projective plane

NASA Astrophysics Data System (ADS)

Anandakrishnan, Archana; Raby, Stuart

2013-03-01

We consider a 6-dimensional supersymmetric SU(6) gauge theory and compactify two extra-dimensions on a multiply-connected manifold with non-trivial topology. The SU(6) is broken down to the Standard Model gauge groups in two steps by an orbifold projection, followed by a Wilson line. The Higgs doublets of the low energy electroweak theory come from a chiral adjoint of SU(6). We thus have gauge-Higgs unification. The three families of the Standard Model can either be located in the 6D bulk or at 4D N=1 supersymmetric fixed points. We calculate the Kaluza-Klein spectrum of states arising as a result of the orbifolding. We also calculate the threshold corrections to the coupling constants due to this tower of states at the lowest compactification scale. We study the regions of parameter space of this model where the threshold corrections are consistent with low energy physics. We find that the couplings receive only logarithmic corrections at all scales. This feature can be attributed to the large N=2 6D SUSY of the underlying model.

Signals of two universal extra dimensions at the LHC

NASA Astrophysics Data System (ADS)

Burdman, G.; Éboli, O. J. P.; Spehler, D.

2016-11-01

Extensions of the standard model with universal extra dimensions are interesting both as phenomenological templates as well as model-building fertile ground. For instance, they are one of the prototypes for theories exhibiting compressed spectra, leading to difficult searches at the LHC since the decay products of new states are soft and immersed in a large standard model background. Here we study the phenomenology at the LHC of theories with two universal extra dimensions. We obtain the current bound by using the production of second level excitations of electroweak gauge bosons decaying to a pair of leptons and study the reach of the LHC Run II in this channel. We also introduce a new channel originating in higher dimensional operators and resulting in the single production of a second level quark excitation. Its subsequent decay into a hard jet and lepton pair resonance would allow the identification of a more model-specific process, unlike the more generic vector resonance signal. We show that the sensitivity of this channel to the compactification scale is very similar to the one obtained using the vector resonance.

Strong anti-gravity Life in the shock wave

NASA Astrophysics Data System (ADS)

Fabbrichesi, Marco; Roland, Kaj

1992-12-01

Strong anti-gravity is the vanishing of the net force between two massive particles at rest, to all orders in Newton's constant. We study this phenomenon and show that it occurs in any effective theory of gravity which is obtained from a higher-dimensional model by compactification on a manifold with flat directions. We find the exact solution of the Einstein equations in the presence of a point-like source of strong anti-gravity by dimensional reduction of a shock-wave solution in the higher-dimensional model.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Garcia-Compean, H.; Loaiza-Brito, O.; Departamento de Fisica, Universidad de Guanajuato, C.P. 37150, Leon, Guanajuato

The first steps towards a proposal for a description of the quantum hair in 4D supersymmetric black holes in string Calabi-Yau (CY) compactifications are given. The quantum hair consisting of electric and magnetic fractional charges in black holes are derived from periods of the CY's torsion cycles. In the process a K-theory interpretation of the quantum hair in terms of the Atiyah-Hirzebruch spectral sequence is carried out. Finally, the same procedure is considered for torsion cycles of certain generalized CY's threefolds such as half-flat manifolds.

Quantum supergravity, supergravity anomalies and string phenomenology

DOE PAGES

Gaillard, Mary K.

2016-03-15

I discuss the role of quantum effects in the phenomenology of effective supergravity theories from compactification of the weakly coupled heterotic string. An accurate incorporation of these effects requires a regularization procedure that respects local supersymmetry and BRST invariance and that retains information associated with the cut-off scale, which has physical meaning in an effective theory. I briefly outline the Pauli–Villars regularization procedure, describe some applications, and comment on what remains to be done to fully define the effective quantum field theory.

Kaluza-Klein cosmology from five-dimensional Lovelock-Cartan theory

NASA Astrophysics Data System (ADS)

Castillo-Felisola, Oscar; Corral, Cristóbal; del Pino, Simón; Ramírez, Francisca

2016-12-01

We study the Kaluza-Klein dimensional reduction of the Lovelock-Cartan theory in five-dimensional spacetime, with a compact dimension of S1 topology. We find cosmological solutions of the Friedmann-Robertson-Walker class in the reduced spacetime. The torsion and the fields arising from the dimensional reduction induce a nonvanishing energy-momentum tensor in four dimensions. We find solutions describing expanding, contracting, and bouncing universes. The model shows a dynamical compactification of the extra dimension in some regions of the parameter space.

A swamp of non-SUSY vacua

NASA Astrophysics Data System (ADS)

Danielsson, U. H.; Dibitetto, G.; Vargas, S. C.

2017-11-01

We consider known examples of non-supersymmetric AdS7 and AdS4 solutions arising from compactifications of massive type IIA supergravity and study their stability, taking into account the coupling between closed- and open-string sector excitations. Generically, open strings are found to develop modes with masses below the Breitenlohner-Freedman (BF) bound. We comment on the relation with the Weak Gravity Conjecture, and how this analysis may play an important role in examining the validity of non-supersymmetric constructions in string theory.

G-structures and domain walls in heterotic theories

NASA Astrophysics Data System (ADS)

Lukas, Andre; Matti, Cyril

2011-01-01

We consider heterotic string solutions based on a warped product of a four-dimensional domain wall and a six-dimensional internal manifold, preserving two supercharges. The constraints on the internal manifolds with SU(3) structure are derived. They are found to be generalized half-flat manifolds with a particular pattern of torsion classes and they include half-flat manifolds and Strominger's complex non-Kahler manifolds as special cases. We also verify that previous heterotic compactifications on half-flat mirror manifolds are based on this class of solutions.

Infinitesimal moduli of G2 holonomy manifolds with instanton bundles

NASA Astrophysics Data System (ADS)

de la Ossa, Xenia; Larfors, Magdalena; Svanes, Eirik E.

2016-11-01

We describe the infinitesimal moduli space of pairs ( Y, V) where Y is a manifold with G 2 holonomy, and V is a vector bundle on Y with an instanton connection. These structures arise in connection to the moduli space of heterotic string compactifications on compact and non-compact seven dimensional spaces, e.g. domain walls. Employing the canonical G 2 cohomology developed by Reyes-Carrión and Fernández and Ugarte, we show that the moduli space decomposes into the sum of the bundle moduli {H}_{{overset{ěe }{d}}_A}^1(Y,End(V)) plus the moduli of the G 2 structure preserving the instanton condition. The latter piece is contained in {H}_{overset{ěe }{d}θ}^1(Y,TY) , and is given by the kernel of a map overset{ěe }{F} which generalises the concept of the Atiyah map for holomorphic bundles on complex manifolds to the case at hand. In fact, the map overset{ěe }{F} is given in terms of the curvature of the bundle and maps {H}_{overset{ěe }{d}θ}^1(Y,TY) into {H}_{{overset{ěe }{d}}_A}^2(Y,End(V)) , and moreover can be used to define a cohomology on an extension bundle of TY by End( V). We comment further on the resemblance with the holomorphic Atiyah algebroid and connect the story to physics, in particular to heterotic compactifications on ( Y, V) when α' = 0.

General U(1)×U(1) F-theory compactifications and beyond: geometry of unHiggsings and novel matter structure

DOE PAGES

Cvetic, Mirjam; Klevers, Denis; Piragua, Hernan; ...

2015-11-30

We construct the general form of an F-theory compactification with two U(1) factors based on a general elliptically fibered Calabi-Yau manifold with Mordell-Weil group of rank two. This construction produces broad classes of models with diverse matter spectra, including many that are not realized in earlier F-theory constructions with U(1)×U(1) gauge symmetry. Generic U(1)×U(1) models can be related to a Higgsed non-Abelian model with gauge group SU(2)×SU(2)×SU(3), SU(2) 3×SU(3), or a subgroup thereof. The nonlocal horizontal divisors of the Mordell-Weil group are replaced with local vertical divisors associated with the Cartan generators of non-Abelian gauge groups from Kodaira singularities. Wemore » give a global resolution of codimension two singularities of the Abelian model; we identify the full anomaly free matter content, and match it to the unHiggsed non-Abelian model. The non-Abelian Weierstrass model exhibits a new algebraic description of the singularities in the fibration that results in the first explicit construction of matter in the symmetric representation of SU(3). This matter is realized on double point singularities of the discriminant locus. In conclusion, the construction suggests a generalization to U(1) k factors with k > 2, which can be studied by Higgsing theories with larger non-Abelian gauge groups.« less

Fluxes, holography and twistors: String theory paths to four dimensions

NASA Astrophysics Data System (ADS)

Gao, Peng

2007-12-01

There are presently three popular paths to obtain four dimensional physics from string theory: compactification, holography and twistor space. We present results in this thesis on each of them, discussing the geometric structure of flux compactifications, the interplay between holography and S -duality in M-theory and the perturbative amplitudes of the marginally deformed super-Yang-Mills theory obtained from topological string theory on a supertwistor space. First we analyze supersymmetric flux compactifications of ten dimensional string theories to four dimensions. Back reaction of the fluxes on the six dimensional internal geometry is characterized by G-structures. In type IIB compactification on SU(3)-structure manifold with N = 1 supersymmetry, we solve the equations dictating the five components of intrinsic torsion. We find that the six dimensional manifold always retains an integrable almost complex structure compatible with supersymmetry. In terms of the various vacuum fields, the axion/dilaton is found to be generically non-holomorphic, and the four dimensional cosmological constant is nonvanishing only if the SU(3) structure group is reduced to SU(2). The equations are solved by one holomorphic function. Around the poles and zeros of the holomorphic function, the geometry locally looks like the well known type-A and type-B solutions. When this function is a constant, the geometry can be viewed as a holographic RG flow. After classifying the type IIB SU(3)-structure flux vacua, we analyze the effect of non-perturbative corrections on the moduli space of N = 2 flux compactifications. At energy below the Kaluza-Klein scale, the four dimensional effective theory is a gauged supergravity theory with vanishing cosmological constant. The gauging of isometries on the hyper-multiplet moduli space is induced by the fluxes. We show that instanton corrections which could potentially lift the gauged isometries are in fact prohibited both in the type IIA and heterotic string theories by the inclusion of flux. Hence gauged supergravity is a robust framework for studying flux vacua even when these stringy effects are taken into account. The mechanisms which protect the gauged isometries are different in the two theories. Then we switch to the understanding of SL(2, Z ) duality transformations in asymptotically AdS4 x S7 spacetime with an Abelian gauge theory. The bulk duality acts non-trivially on the three-dimensional SCFT of coincident M2-branes on the conformal boundary. We develop a systematic method to holographically obtain the deformations of the boundary CFT manifested by generalized boundary conditions and show how SL(2, Z ) duality relates different deformations of the conformal vacuum. We analyze in detail marginal deformations and deformations by dimension 4 operators. In the case of massive deformations, the RG flow induces a Legendre transform as well as S-duality. Correlation functions in the CFT are computed by differentiating with respect to magnetic bulk sources, whereas correlation functions in the Legendre dual CFT are computed using electric bulk sources. Under massive deformations, the boundary effective action is generically minimized by massive self-dual configurations of the U(1) gauge field. We show that a massive and self-dual boundary condition corresponds to the unique self-dual topologically massive gauge theory in three dimensions. Thus, self-duality in three dimensions can be understood as a consequence of SL(2, Z ) invariance in the bulk of AdS4. We discuss various implications for understanding the strongly interacting worldvolume theory of M2-branes and more general dualities of the maximally supersymmetric AdS4 supergravity theory. Finally we study the twistor string theory whose D-instanton expansion gives the perturbative expansion of marginally deformed N = 4 super-Yang-Mills theories. More precisely this string theory is a topological B-model with both open and closed string sectors with target space CP3|4 , a super-Calabi-Yau manifold. The tree-level amplitudes in the N = 1 beta-deformed field theory are exactly reproduced by introducing non-anticommutative star-products among the D1 and D5 open strings. A related star-product gives the tree-level amplitudes of the non-supersymmetric gamma-deformed conformal field theory. The non-anticommutativity arises essentially from the deformation of the supertwistor space which reduces the amount of superconformal symmetries realized by the supertwistor space. The tree-level gluonic amplitudes in more general marginally deformed field theories are also discussed using twistor string theory.

Matrix theory interpretation of discrete light cone quantization string worldsheets

PubMed

Grignani; Orland; Paniak; Semenoff

2000-10-16

We study the null compactification of type-IIA string perturbation theory at finite temperature. We prove a theorem about Riemann surfaces establishing that the moduli spaces of infinite-momentum-frame superstring worldsheets are identical to those of branched-cover instantons in the matrix-string model conjectured to describe M theory. This means that the identification of string degrees of freedom in the matrix model proposed by Dijkgraaf, Verlinde, and Verlinde is correct and that its natural generalization produces the moduli space of Riemann surfaces at all orders in the genus expansion.

A no-go theorem for monodromy inflation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Andriot, David, E-mail: david.andriot@aei.mpg.de

2016-03-01

We study the embedding of the monodromy inflation mechanism by E. Silverstein and A. Westphal (2008) in a concrete compactification setting. To that end, we look for an appropriate vacuum of type IIA supergravity, corresponding to the minimum of the inflaton potential. We prove a no-go theorem on the existence of such a vacuum, using ten-dimensional equations of motion. Anti-de Sitter and Minkowski vacua are ruled out; de Sitter vacua are not excluded, but have a lower bound on their cosmological constant which is too high for phenomenology.

Hyperboloidal evolution of test fields in three spatial dimensions

NASA Astrophysics Data System (ADS)

Zenginoǧlu, Anıl; Kidder, Lawrence E.

2010-06-01

We present the numerical implementation of a clean solution to the outer boundary and radiation extraction problems within the 3+1 formalism for hyperbolic partial differential equations on a given background. Our approach is based on compactification at null infinity in hyperboloidal scri fixing coordinates. We report numerical tests for the particular example of a scalar wave equation on Minkowski and Schwarzschild backgrounds. We address issues related to the implementation of the hyperboloidal approach for the Einstein equations, such as nonlinear source functions, matching, and evaluation of formally singular terms at null infinity.

Modularity, quaternion-Kähler spaces, and mirror symmetry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Alexandrov, Sergei; Banerjee, Sibasish

2013-10-15

We provide an explicit twistorial construction of quaternion-Kähler manifolds obtained by deformation of c-map spaces and carrying an isometric action of the modular group SL(2,Z). The deformation is not assumed to preserve any continuous isometry and therefore this construction presents a general framework for describing NS5-brane instanton effects in string compactifications with N= 2 supersymmetry. In this context the modular invariant parametrization of twistor lines found in this work yields the complete non-perturbative mirror map between type IIA and type IIB physical fields.

History of Power Transmission Technologies and Future Prospects of Power System of Chubu Electric Power Company

NASA Astrophysics Data System (ADS)

Takagi, Hirotaka; Sugiyama, Tomonari; Zashibo, Toshihito

Since its foundation, the power system of Chubu Electric Power Company (hereinafter CEPCO) has developed through power source and transmission facility formation to meet electricity demand increases. This development has been accompanied by progress in transmission technologies including capacity scale-up, compactification and power system stabilization to operate complex power systems. Now, changes in business situation due to electricity market liberalizatin may bring new challenges to future facility formation. This paper reviews CEPCO's history of power system formation and progress in transmission technologies, and describes future challenges.

3d-3d correspondence revisited

NASA Astrophysics Data System (ADS)

Chung, Hee-Joong; Dimofte, Tudor; Gukov, Sergei; Sułkowski, Piotr

2016-04-01

In fivebrane compactifications on 3-manifolds, we point out the importance of all flat connections in the proper definition of the effective 3d {N}=2 theory. The Lagrangians of some theories with the desired properties can be constructed with the help of homological knot invariants that categorify colored Jones polynomials. Higgsing the full 3d theories constructed this way recovers theories found previously by Dimofte-Gaiotto-Gukov. We also consider the cutting and gluing of 3-manifolds along smooth boundaries and the role played by all flat connections in this operation.

3d-3d correspondence revisited

DOE PAGES

Chung, Hee -Joong; Dimofte, Tudor; Gukov, Sergei; ...

2016-04-21

In fivebrane compactifications on 3-manifolds, we point out the importance of all flat connections in the proper definition of the effective 3d N = 2 theory. The Lagrangians of some theories with the desired properties can be constructed with the help of homological knot invariants that categorify colored Jones polynomials. Higgsing the full 3d theories constructed this way recovers theories found previously by Dimofte-Gaiotto-Gukov. As a result, we also consider the cutting and gluing of 3-manifolds along smooth boundaries and the role played by all flat connections in this operation.

Twistor approach to string compactifications: A review

NASA Astrophysics Data System (ADS)

Alexandrov, Sergei

2013-01-01

We review a progress in obtaining the complete non-perturbative effective action of type II string theory compactified on a Calabi-Yau manifold. This problem is equivalent to understanding quantum corrections to the metric on the hypermultiplet moduli space. We show how all these corrections, which include D-brane and NS5-brane instantons, are incorporated in the framework of the twistor approach, which provides a powerful mathematical description of hyperkähler and quaternion-Kähler manifolds. We also present new insights on S-duality, quantum mirror symmetry, connections to integrable models and topological strings.

d-Brane Instantons in Type II Orientifolds

NASA Astrophysics Data System (ADS)

Blumenhagen, Ralph; Cvetič, Mirjam; Kachru, Shamit; Weigand, Timo

2009-11-01

We review recent progress in determining the effects of d-brane instantons in [Formula: see text] supersymmetric compactifications of Type II string theory to four dimensions. We describe the abstract d-brane instanton calculus for holomorphic couplings such as the superpotential, the gauge kinetic function, and higher fermionic F-terms, and we briefly discuss the implications of background fluxes for the instanton sector. We then summarize the concrete consequences of stringy d-brane instantons for the construction of semirealistic models of particle physics or supersymmetry breaking in compact and noncompact geometries.

Convergence of quantum electrodynamics in a curved modification of Minkowski space.

PubMed Central

Segal, I E; Zhou, Z

1994-01-01

The interaction and total hamiltonians for quantum electrodynamics, in the interaction representation, are entirely regular self-adjoint operators in Hilbert space, in the universal covering manifold M of the conformal compactification of Minkowski space Mo. (M is conformally equivalent to the Einstein universe E, in which Mo may be canonically imbedded.) In a fixed Lorentz frame this may be expressed as convergence in a spherical space with suitable periodic boundary conditions in time. The traditional relativistic theory is the formal limit of the present variant as the space curvature vanishes. PMID:11607455

Fermionic minimal dark matter in 5D gauge-Higgs unification

NASA Astrophysics Data System (ADS)

Maru, Nobuhito; Okada, Nobuchika; Okada, Satomi

2017-12-01

We propose a minimal dark matter (MDM) scenario in the context of a simple gauge-Higgs unification (GHU) model based on the gauge group S U (3 )×U (1 )' in five-dimensional Minkowski space with a compactification of the fifth dimension on the 1S/Z2 orbifold. A pair of vectorlike S U (3 ) multiplet fermions in a higher-dimensional representation is introduced in the bulk, and the DM particle is identified with the lightest mass eigenstate among the components in the multiplets. In the original model description, the DM particle communicates with the Standard Model (SM) particles only through the bulk gauge interaction, and hence our model is the GHU version of the MDM scenario. There are two typical realizations of the DM particle in four-dimensional effective theory: (i) the DM particle is mostly composed of the SM S U (2 )L multiplets, or (ii) the DM is mostly composed of the SM S U (2 )L singlets. Since the case (i) is very similar to the original MDM scenario, we focus on the case (ii), which is a realization of the Higgs-portal DM scenario in the context of the GHU model. We identify an allowed parameter region to be consistent with the current experimental constraints, which will be fully covered by the direct dark matter detection experiments in the near future. In the presence of the bulk multiplet fermions in higher-dimensional S U (3 ) representations, we reproduce the 125 GeV Higgs boson mass through the renormalization group evolution of Higgs quartic coupling with the compactification scale of 10-100 TeV.

On the dynamics of superstring compactification

NASA Astrophysics Data System (ADS)

Pollock, M. D.

2018-05-01

Compactification of the ten-dimensional heterotic superstring theory to four dimensions gives rise to two moduli potentials VA, VB, the positive semi-definiteness of which places constraints on the Euler characteristic \\bar{χ} of the internal space \\bar{g}_{μν}(y^{ξ}) and the adiabatic index γ of the effective matter source of energy-density ρ and pressure p = (γ -1)ρ that generates the physical four-space g_{ij}(xk), namely \\bar{χ} < 0, 4/3 ≤ γ ≤ 2, or \\bar{χ} > 0, 1 ≤ γ ≤ 4/3. Here, we show how fermion-bilinear condensation in the internal space, first put forward by Helayël-Neto and Smith, determines the field \\tilde{β} ≡ A_r B_r3, thus reducing the moduli space to a single canonical field \\tilde{σ}=2σB with a potential ˜ , which is positive semi-definite under the same conditions that ensure positive semi-definiteness of VA, VB, and has a minimum at a value of \\tilde{β} that is approximately constant far from the Planck era at t ≫ t_P. The fields σA, σB, which are canonically normalized in the zero-slope limit, are modified by contributions originating from the higher-derivative gravitational terms α^' \\hatR_E2 and α^' 3} \\hatR4, but the associated kinetic energy remains positive for times t ≳ t_P/2, guaranteeing classical stability of the solution, since the generalized indeterminacy principle implies a minimum physically measurable time t0 ≈ 50 t_P for the superstring theory.

The edge of supersymmetry: Stability walls in heterotic theory

DOE PAGES

Anderson, Lara B.; Gray, James; Lukas, Andre; ...

2009-05-15

We explicitly describe, in the language of four-dimensional N = 1 supersymmetric field theory, what happens when the moduli of a heterotic Calabi-Yau compactification change so as to make the internal non-Abelian gauge fields non-supersymmetric. At the edge of the region in Kähler moduli space where supersymmetry can be preserved, an additional anomalous U(1) gauge symmetry appears in the four-dimensional theory. The D-term contribution to the scalar potential associated to this U(1) attempts to force the system back into a supersymmetric configuration and provides a consistent low-energy description of gauge bundle stability.

Generating the curvature perturbation at the end of inflation in string theory.

PubMed

Lyth, David H; Riotto, Antonio

2006-09-22

In brane inflationary scenarios, the cosmological perturbations are supposed to originate from the vacuum fluctuations of the inflaton field corresponding to the position of the brane. We show that a significant, and possibly dominant, contribution to the curvature perturbation is generated at the end of inflation through the vacuum fluctuations of fields, other than the inflaton, which are light during the inflationary trajectory and become heavy at the brane-antibrane annihilation. These fields appear generically in string compactifications where the background geometry has exact or approximate isometries and parametrize the internal angular directions of the brane.

Marginal deformations of heterotic G 2 sigma models

NASA Astrophysics Data System (ADS)

Fiset, Marc-Antoine; Quigley, Callum; Svanes, Eirik Eik

2018-02-01

Recently, the infinitesimal moduli space of heterotic G 2 compactifications was described in supergravity and related to the cohomology of a target space differential. In this paper we identify the marginal deformations of the corresponding heterotic nonlinear sigma model with cohomology classes of a worldsheet BRST operator. This BRST operator is nilpotent if and only if the target space geometry satisfies the heterotic supersymmetry conditions. We relate this to the supergravity approach by showing that the corresponding cohomologies are indeed isomorphic. We work at tree-level in α' perturbation theory and study general geometries, in particular with non-vanishing torsion.

D-type conformal matter and SU/USp quivers

NASA Astrophysics Data System (ADS)

Kim, Hee-Cheol; Razamat, Shlomo S.; Vafa, Cumrun; Zafrir, Gabi

2018-06-01

We discuss the four dimensional models obtained by compactifying a single M5 brane probing D N singularity (minimal D-type (1 , 0) conformal matter in six dimensions) on a torus with flux for abelian subgroups of the SO(4 N) flavor symmetry. We derive the resulting quiver field theories in four dimensions by first compactifying on a circle and relating the flux to duality domain walls in five dimensions. This leads to novel N=1 dualities in 4 dimensions which arise from distinct five dimensional realizations of the circle compactifications of the D-type conformal matter.

Weak coupling limit of F-theory models with MSSM spectrum and massless U(1)'s

NASA Astrophysics Data System (ADS)

Mayorga Peña, Damián Kaloni; Valandro, Roberto

2018-03-01

We consider the Sen limit of several global F-theory compactifications, some of which exhibit an MSSM-like spectrum. We show that these indeed have a consistent limit where they can be viewed as resulting from an intersecting brane configuration in type IIB. We discuss the match of the fluxes and the chiral spectrum in detail. We find that some D5-tadpole canceling gauge fluxes do not lift to harmonic vertical four-form fluxes in the resolved F-theory manifold. We discuss the connection between splitting of curves at weak coupling and remnant discrete symmetries.

Flat connections in open string mirror symmetry

NASA Astrophysics Data System (ADS)

Alim, Murad; Hecht, Michael; Jockers, Hans; Mayr, Peter; Mertens, Adrian; Soroush, Masoud

2012-06-01

We study a flat connection defined on the open-closed deformation space of open string mirror symmetry for type II compactifications on Calabi-Yau threefolds with D-branes. We use flatness and integrability conditions to define distinguished flat coordinates and the superpotential function at an arbitrary point in the open-closed deformation space. Integrability conditions are given for concrete deformation spaces with several closed and open string deformations. We study explicit examples for expansions around different limit points, including orbifold Gromov-Witten invariants, and brane configurations with several brane moduli. In particular, the latter case covers stacks of parallel branes with non-Abelian symmetry.

Extra-dimensional models on the lattice

DOE PAGES

Knechtli, Francesco; Rinaldi, Enrico

2016-08-05

In this paper we summarize the ongoing effort to study extra-dimensional gauge theories with lattice simulations. In these models the Higgs field is identified with extra-dimensional components of the gauge field. The Higgs potential is generated by quantum corrections and is protected from divergences by the higher dimensional gauge symmetry. Dimensional reduction to four dimensions can occur through compactification or localization. Gauge-Higgs unification models are often studied using perturbation theory. Numerical lattice simulations are used to go beyond these perturbative expectations and to include nonperturbative effects. We describe the known perturbative predictions and their fate in the strongly-coupled regime formore » various extra-dimensional models.« less

Implementing odd-axions in dimensional oxidation of 4D non-geometric type IIB scalar potential

NASA Astrophysics Data System (ADS)

Shukla, Pramod

2016-01-01

In a setup of type IIB superstring compactification on an orientifold of a T6 /Z4 sixfold, the presence of geometric flux (ω) and non-geometric fluxes (Q, R) is implemented along with the standard NS-NS and RR three-form fluxes (H, F). After computing the F/D-term contributions to the N = 1 four dimensional effective scalar potential, we rearrange the same into 'suitable' pieces by using a set of new generalized flux orbits. Subsequently, we dimensionally oxidize the various pieces of the total four dimensional scalar potential to guess their ten-dimensional origin.

Counting spinning dyons in maximal supergravity: the Hodge-elliptic genus for tori

NASA Astrophysics Data System (ADS)

Benjamin, Nathan; Kachru, Shamit; Tripathy, Arnav

2017-11-01

We consider M-theory compactified on T^4 × T^2 and describe the count of spinning 1/8-BPS states. This builds on the work of Maldacena-Moore-Strominger in the physics literature. It simultaneously provides a refinement of the recent mathematical work of Bryan-Oberdieck-Pandharipande-Yin and Oberdieck-Shen, which studied (non-motivic) reduced Donaldson-Thomas invariants of abelian surfaces and threefolds. As in previous work on K3 × T^2 compactification, we track angular momenta under both the SU(2)_L and SU(2)_R factors in the 5d little group, providing predictions for the relevant motivic curve counts.

COBE satellite measurement, hyperspheres, superstrings and the dimension of spacetime.

NASA Astrophysics Data System (ADS)

El Naschie, M. S.

1998-08-01

The first part of the paper attempts to establish connections between hypersphere backing in infinite dimensions, the expectation value of dimE(∞) spacetime and the COBE measurement of the microwave background radiation. One of the main results reported here is that the mean sphere in S(∞) spans a four dimensional manifold and is thus equal to the expectation value of the topological dimension of E(∞). In the second part the author introduces within a general theory, a probabilistic justification for a compactification which reduces an infinite dimensional spacetime E(∞) (n = ∞) to a four dimensional one (DT = n = 4).

Beauty and the beast: Superconformal symmetry in a monster module

NASA Astrophysics Data System (ADS)

Dixon, L.; Ginsparg, P.; Harvey, J.

1988-06-01

Frenkel, Lepowsky, and Meurman have constructed a representation of the largest sporadic simple finite group, the Fischer-Griess monster, as the automorphism group of the operator product algebra of a conformal field theory with central charge c=24. In string terminology, their construction corresponds to compactification on a Z 2 asymmetric orbifold constructed from the torus R 24/∧, where ∧ is the Leech lattice. In this note we point out that their construction naturally embodies as well a larger algebraic structure, namely a super-Virasoro algebra with central charge ĉ=16, with the supersymmetry generator constructed in terms of bosonic twist fields.

A Brane Model, Its Ads-DS States and Their Agitated Extra Dimensions

NASA Astrophysics Data System (ADS)

Günther, Uwe; Vargas Moniz, Paulo; Zhuk, Alexander

2006-02-01

We consider multidimensional gravitational models with a nonlinear scalar curvature term and form fields. It is assumed that the higher dimensional spacetime undergoes a spontaneous compactification to a warped product manifold. Particular attention is paid to models with quadratic scalar curvature terms and a Freund-Rubin-like ansatz for solitonic form fields. It is shown that for certain parameter ranges the extra dimensions are stabilized for any sign of the internal space curvature, the bulk cosmological constant and of the effective four-dimensional cosmological constant. Moreover, the effective cosmological constant can satisfy the observable limit on the dark energy density.

Trapped Inflation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Green, Daniel; Horn, Bart; /SLAC /Stanford U., Phys. Dept.

2009-06-19

We analyze a distinctive mechanism for inflation in which particle production slows down a scalar field on a steep potential, and show how it descends from angular moduli in string compactifications. The analysis of density perturbations - taking into account the integrated effect of the produced particles and their quantum fluctuations - requires somewhat new techniques that we develop. We then determine the conditions for this effect to produce sixty e-foldings of inflation with the correct amplitude of density perturbations at the Gaussian level, and show that these requirements can be straightforwardly satisfied. Finally, we estimate the amplitude of themore » non-Gaussianity in the power spectrum and find a significant equilateral contribution.« less

Cubic polynomial maps with periodic critical orbit, Part II

NASA Astrophysics Data System (ADS)

Bonifant, Araceli; Kiwi, Jan; Milnor, John

The parameter space S_p for monic centered cubic polynomial maps with a marked critical point of period p is a smooth affine algebraic curve whose genus increases rapidly with p . Each S_p consists of a compact connectedness locus together with finitely many escape regions, each of which is biholomorphic to a punctured disk and is characterized by an essentially unique Puiseux series. This note will describe the topology of S_p , and of its smooth compactification, in terms of these escape regions. In particular, it computes the Euler characteristic. It concludes with a discussion of the real sub-locus of S_p .

Relative Energy Shift of a Two-Level Atom in a Cylindrical Spacetime

NASA Astrophysics Data System (ADS)

Zhang, Jia-Lin

2012-11-01

We investigate the evolution dynamics of a two-level atom system interacting with the massless scalar field in a Cylindrical spacetime. We find that both the energy shifts of ground state and excited state can be separated into two parts due to the vacuum fluctuations. One is the corresponding energy shift for a rest atom in four-dimensional Minkowski space without spatial compactification, the other is just the modification of the spatial compactified periodic length. It will reveal that the influence of the presence of one spatial compactified dimension can not be neglected in Lamb shift as the relative energy level shift of an atom.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kodama, Yuta; Kokubu, Kento; Sawado, Nobuyuki

We construct brane solutions in 6-dimensional Einstein-Skyrme systems. A class of baby-Skyrmion solutions realizes warped compactification of the extra dimensions and gravity localization on the brane for the negative bulk cosmological constant. Coupling of the fermions with brane Skyrmions leads to brane localized fermions. In terms of the level crossing picture, emergence of the massive localized modes are observed. The nonlinear nature of Skyrmions brings richer information for the fermions' level structure. It comprises doubly degenerate lowest plus single excited modes. Three generations of fundamental fermions are associated with this distinctive structure. The mass hierarchy of quarks or leptons appearedmore » in terms of slightly deformed baby Skyrmions with topological charge three.« less

Micro-orbits in a many-brane model and deviations from Newton's 1/r^2 law

NASA Astrophysics Data System (ADS)

Donini, A.; Marimón, S. G.

2016-12-01

We consider a five-dimensional model with geometry M = M_4 × S_1, with compactification radius R. The Standard Model particles are localized on a brane located at y=0, with identical branes localized at different points in the extra dimension. Objects located on our brane can orbit around objects located on a brane at a distance d=y/R, with an orbit and a period significantly different from the standard Newtonian ones. We study the kinematical properties of the orbits, finding that it is possible to distinguish one motion from the other in a large region of the initial conditions parameter space. This is a warm-up to study if a SM-like mass distribution on one (or more) distant brane(s) may represent a possible dark matter candidate. After using the same technique to the study of orbits of objects lying on the same brane (d=0), we apply this method to the detection of generic deviations from the inverse-square Newton law. We propose a possible experimental setup to look for departures from Newtonian motion in the micro-world, finding that an order of magnitude improvement on present bounds can be attained at the 95% CL under reasonable assumptions.

Scanning the skeleton of the 4D F-theory landscape

NASA Astrophysics Data System (ADS)

Taylor, Washington; Wang, Yi-Nan

2018-01-01

Using a one-way Monte Carlo algorithm from several different starting points, we get an approximation to the distribution of toric threefold bases that can be used in four-dimensional F-theory compactification. We separate the threefold bases into "resolvable" ones where the Weierstrass polynomials ( f, g) can vanish to order (4 , 6) or higher on codimension-two loci and the "good" bases where these (4 , 6) loci are not allowed. A simple estimate suggests that the number of distinct resolvable base geometries exceeds 103000, with over 10250 "good" bases, though the actual numbers are likely much larger. We find that the good bases are concentrated at specific "end points" with special isolated values of h 1,1 that are bigger than 1,000. These end point bases give Calabi-Yau fourfolds with specific Hodge numbers mirror to elliptic fibrations over simple threefolds. The non-Higgsable gauge groups on the end point bases are almost entirely made of products of E 8, F 4, G 2 and SU(2). Nonetheless, we find a large class of good bases with a single non-Higgsable SU(3). Moreover, by randomly contracting the end point bases, we find many resolvable bases with h 1,1( B) ˜ 50-200 that cannot be contracted to another smooth threefold base.

Large Volume, Behaviorally-relevant Illumination for Optogenetics in Non-human Primates.

PubMed

Acker, Leah C; Pino, Erica N; Boyden, Edward S; Desimone, Robert

2017-10-03

This protocol describes a large-volume illuminator, which was developed for optogenetic manipulations in the non-human primate brain. The illuminator is a modified plastic optical fiber with etched tip, such that the light emitting surface area is > 100x that of a conventional fiber. In addition to describing the construction of the large-volume illuminator, this protocol details the quality-control calibration used to ensure even light distribution. Further, this protocol describes techniques for inserting and removing the large volume illuminator. Both superficial and deep structures may be illuminated. This large volume illuminator does not need to be physically coupled to an electrode, and because the illuminator is made of plastic, not glass, it will simply bend in circumstances when traditional optical fibers would shatter. Because this illuminator delivers light over behaviorally-relevant tissue volumes (≈ 10 mm 3 ) with no greater penetration damage than a conventional optical fiber, it facilitates behavioral studies using optogenetics in non-human primates.

A general method for assessing the effects of uncertainty in individual-tree volume model predictions on large-area volume estimates with a subtropical forest illustration

Treesearch

Ronald E. McRoberts; Paolo Moser; Laio Zimermann Oliveira; Alexander C. Vibrans

2015-01-01

Forest inventory estimates of tree volume for large areas are typically calculated by adding the model predictions of volumes for individual trees at the plot level, calculating the mean over plots, and expressing the result on a per unit area basis. The uncertainty in the model predictions is generally ignored, with the result that the precision of the large-area...

The persistence of the large volumes in black holes

NASA Astrophysics Data System (ADS)

Ong, Yen Chin

2015-08-01

Classically, black holes admit maximal interior volumes that grow asymptotically linearly in time. We show that such volumes remain large when Hawking evaporation is taken into account. Even if a charged black hole approaches the extremal limit during this evolution, its volume continues to grow; although an exactly extremal black hole does not have a "large interior". We clarify this point and discuss the implications of our results to the information loss and firewall paradoxes.

The physics of large eruptions

NASA Astrophysics Data System (ADS)

Gudmundsson, Agust

2015-04-01

Based on eruptive volumes, eruptions can be classified as follows: small if the volumes are from less than 0.001 km3 to 0.1 km3, moderate if the volumes are from 0.1 to 10 km3, and large if the volumes are from 10 km3 to 1000 km3 or larger. The largest known explosive and effusive eruptions have eruptive volumes of 4000-5000 km3. The physics of small to moderate eruptions is reasonably well understood. For a typical mafic magma chamber in a crust that behaves as elastic, about 0.1% of the magma leaves the chamber (erupted and injected as a dyke) during rupture and eruption. Similarly, for a typical felsic magma chamber, the eruptive/injected volume during rupture and eruption is about 4%. To provide small to moderate eruptions, chamber volumes of the order of several tens to several hundred cubic kilometres would be needed. Shallow crustal chambers of these sizes are common, and deep-crustal and upper-mantle reservoirs of thousands of cubic kilometres exist. Thus, elastic and poro-elastic chambers of typical volumes can account for small to moderate eruptive volumes. When the eruptions become large, with volumes of tens or hundreds of cubic kilometres or more, an ordinary poro-elastic mechanism can no longer explain the eruptive volumes. The required sizes of the magma chambers and reservoirs to explain such volumes are simply too large to be plausible. Here I propose that the mechanics of large eruptions is fundamentally different from that of small to moderate eruptions. More specifically, I suggest that all large eruptions derive their magmas from chambers and reservoirs whose total cavity-volumes are mechanically reduced very much during the eruption. There are two mechanisms by which chamber/reservoir cavity-volumes can be reduced rapidly so as to squeeze out much of, or all, their magmas. One is piston-like caldera collapse. The other is graben subsidence. During large slip on the ring-faults/graben-faults the associated chamber/reservoir shrinks in volume, thereby maintaining the excess magmatic pressure much longer than is possible in the ordinary poro-elastic mechanism. Here the physics of caldera subsidence and graben subsidence is regarded as basically the same. The geometric difference in the surface expression is simply a reflection of the horizontal cross-sectional shape of the underlying magma body. In this new mechanism, the large eruption is the consequence -- not the cause -- of the caldera/graben subsidence. Thus, once the conditions for large-scale subsidence of a caldera/graben during an unrest period are established, then the likelihood of large to very large eruptions can be assessed and used in reliable forecasting. Gudmundsson, A., 2012. Strengths and strain energies of volcanic edifices: implications for eruptions, collapse calderas and landslides. Nat. Hazards Earth Syst. Sci., 12, 2241-2258. Gudmundsson, A., 2014. Energy release in great earthquakes and eruptions. Front. Earth Science 2:10. doi: 10.3389/feart.2014.00010 Gudmundsson, A., Acocella, V., 2015.Volcanotectonics: Understanding the Structure, Deformation, and Dynamics of Volcanoes. Cambridge University Press (published 2015).

Applications of warped geometries: From cosmology to cold atoms

NASA Astrophysics Data System (ADS)

Brown, C. M.

This thesis describes several interrelated projects furthering the study of branes on warped geometries in string theory. First, we consider the non-perturbative interaction between D3 and D7 branes which stabilizes the overall volume in braneworld compactification scenarios. This interaction might offer stable nonsupersymmetric vacua which would naturally break supersymmetry if occupied by D3 branes. We derive the equations for the nonsupersymmetric vacua of the D3-brane and analyze them in the case of two particular 7-brane embeddings at the bottom of the warped deformed conifold. These geometries have negative dark energy. Stability of these models is possible but not generic. Further, we reevaluate brane/flux annihilation in a warped throat with one stabilized Kahler modulus. We find that depending on the relative size of various fluxes three things can occur: the decay process proceeds unhindered, the D3-branes are forbidden to decay classically, or the entire space decompactifies. Additionally, we show that the Kahler modulus receives a contribution from the collective 3-brane tension allowing significant changes in the compactified volume during the transition. Next, furthering the effort to describe cold atoms using AdS/CFT, we construct charged asymptotically Schrodinger black hole solutions of IIB supergravity. We begin by obtaining a closed-form expression for the null Melvin twist of many type IIB backgrounds and identify the resulting five-dimensional effective action. We use these results to demonstrate that the near-horizon physics and thermodynamics of asymptotically Schrodinger black holes obtained in this way are essentially inherited from their AdS progenitors, and verify that they admit zero-temperature extremal limits with AdS2 near-horizon geometries. Finally, in an effort to understand rotating nonrelativistic systems we use the null Melvin twist technology on a charged rotating AdS black hole and discover a type of Godel space-time. We discuss how the dual field theory avoids the closed time-like curves which arise because of Bousso's holographic screen conjecture. This Godel space-time is locally equivalent to a Schrodinger space-time that has been forced onto an S2.

Unifying Type-II Strings by Exceptional Groups

NASA Astrophysics Data System (ADS)

Arvanitakis, Alex S.; Blair, Chris D. A.

2018-05-01

We construct the exceptional sigma model: a two-dimensional sigma model coupled to a supergravity background in a manifestly (formally) ED (D )-covariant manner. This formulation of the background is provided by exceptional field theory (EFT), which unites the metric and form fields of supergravity in ED (D ) multiplets before compactification. The realization of the symmetries of EFT on the world sheet uniquely fixes the Weyl-invariant Lagrangian and allows us to relate our action to the usual type-IIA fundamental string action and a form of the type-IIB (m , n ) action. This uniqueness "predicts" the correct form of the couplings to gauge fields in both Neveu-Schwarz and Ramond sectors, without invoking supersymmetry.

Background Independence and Duality Invariance in String Theory.

PubMed

Hohm, Olaf

2017-03-31

Closed string theory exhibits an O(D,D) duality symmetry on tori, which in double field theory is manifest before compactification. I prove that to first order in α^{'} there is no manifestly background independent and duality invariant formulation of bosonic string theory in terms of a metric, b field, and dilaton. To this end I use O(D,D) invariant second order perturbation theory around flat space to show that the unique background independent candidate expression for the gauge algebra at order α^{'} is inconsistent with the Jacobi identity. A background independent formulation exists instead for frame variables subject to α^{'}-deformed frame transformations (generalized Green-Schwarz transformations). Potential applications for curved backgrounds, as in cosmology, are discussed.

Dualities in CHL-models

NASA Astrophysics Data System (ADS)

Persson, Daniel; Volpato, Roberto

2018-04-01

We define a very general class of CHL-models associated with any string theory S (bosonic or supersymmetric) compactified on an internal CFT C× Td . We take the orbifold by a pair (g, δ) , where g is a (possibly non-geometric) symmetry of C and δ is a translation along T n . We analyze the T-dualities of these models and show that in general they contain Atkin–Lehner type symmetries. This generalizes our previous work on N=4 CHL-models based on heterotic string theory on T 6 or type II on K3× T2 , as well as the ‘monstrous’ CHL-models based on a compactification of heterotic string theory on the Frenkel–Lepowsky–Meurman CFT V\

The refined Swampland Distance Conjecture in Calabi-Yau moduli spaces

NASA Astrophysics Data System (ADS)

Blumenhagen, Ralph; Klaewer, Daniel; Schlechter, Lorenz; Wolf, Florian

2018-06-01

The Swampland Distance Conjecture claims that effective theories derived from a consistent theory of quantum gravity only have a finite range of validity. This will imply drastic consequences for string theory model building. The refined version of this conjecture says that this range is of the order of the naturally built in scale, namely the Planck scale. It is investigated whether the Refined Swampland Distance Conjecture is consistent with proper field distances arising in the well understood moduli spaces of Calabi-Yau compactification. Investigating in particular the non-geometric phases of Kähler moduli spaces of dimension h 11 ∈ {1 , 2 , 101}, we always find proper field distances that are smaller than the Planck-length.

U(1){sub R} mediation from the flux compactification in six dimensions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Hyun Min

We consider a supersymmetric completion of codimension-two branes with nonzero tension in a 6D gauged supergravity. As a consequence, we obtain the football solution with 4D Minkowski space as a new supersymmetric background that preserves 4D N = 1 SUSY. In the presence of brane multiplets, we derive the 4D effective supergravity action for the football background and show that the remaining modulus can be stabilized by a bulk non-perturbative correction with brane uplifting potentials at a zero vacuum energy. We find that the U(1){sub R} mediation can be a dominant source of SUSY breaking for a brane scalar withmore » nonzero R charge.« less

Periodic arrays of M2-branes

NASA Astrophysics Data System (ADS)

Jeon, Imtak; Lambert, Neil; Richmond, Paul

2012-11-01

We consider periodic arrays of M2-branes in the ABJM model in the spirit of a circle compactification to D2-branes in type IIA string theory. The result is a curious formulation of three-dimensional maximally supersymmetric Yang-Mills theory in terms of fermions, seven transverse scalars, a non-dynamical gauge field and an additional scalar `dual gluon'. Upon further T-duality on a transverse torus we obtain a non-manifest- Lorentz-invariant description of five-dimensional maximally supersymmetric Yang-Mills. Here the additional scalar field can be thought of as the components of a two-form along the torus. This action can be viewed as an M-theory description of M5-branes on {{{T}}^3}.

Millicharged dark matter in quantum gravity and string theory.

PubMed

Shiu, Gary; Soler, Pablo; Ye, Fang

2013-06-14

We examine the millicharged dark matter scenario from a string theory perspective. In this scenario, kinetic and mass mixings of the photon with extra U(1) bosons are claimed to give rise to small electric charges, carried by dark matter particles, whose values are determined by continuous parameters of the theory. This seems to contradict folk theorems of quantum gravity that forbid the existence of irrational charges in theories with a single massless gauge field. By considering the underlying structure of the U(1) mass matrix that appears in type II string compactifications, we show that millicharges arise exclusively through kinetic mixing, and require the existence of at least two exactly massless gauge bosons.

Comments on A, B, C chains of heterotic and Type II vacua

NASA Astrophysics Data System (ADS)

Candelas, Philip; Perevalov, Eugene; Rajesh, Govindan

1997-02-01

We construct, as hypersurfaces in toric varieties, Calabi-Yau manifolds corresponding to F-theory vacua dual to E8 × E8 heterotic strings compactified to six dimensions on K3 surfaces with non-semisimple gauge backgrounds. These vacua were studied in the recent work of Aldazabal, Font, Ibáñez and Uranga as well as by Klemm, Mayr and Vafa. We extend their results by constructing many more examples, corresponding to enhanced gauge symmetries, by noting that they can be obtained from previously known Calabi-Yau manifolds corresponding to K3 compactification of heterotic strings with simple gauge backgrounds by means of extremal transitions of the conifold type.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baguet, A.; Pope, Christopher N.; Samtleben, H.

We prove an old conjecture by Duff, Nilsson, Pope and Warner asserting that the NSNS sector of supergravity (and more general the bosonic string) allows for a consistent Pauli reduction on any d-dimensional group manifold G, keeping the full set of gauge bosons of the G×G isometry group of the bi-invariant metric on G. The main tool of the construction is a particular generalised Scherk–Schwarz reduction ansatz in double field theory which we explicitly construct in terms of the group's Killing vectors. Examples include the consistent reduction from ten dimensions on S3×S3 and on similar product spaces. The construction ismore » another example of globally geometric non-toroidal compactifications inducing non-geometric fluxes.« less

Large volume continuous counterflow dialyzer has high efficiency

NASA Technical Reports Server (NTRS)

Mandeles, S.; Woods, E. C.

1967-01-01

Dialyzer separates macromolecules from small molecules in large volumes of solution. It takes advantage of the high area/volume ratio in commercially available 1/4-inch dialysis tubing and maintains a high concentration gradient at the dialyzing surface by counterflow.

Technologies for imaging neural activity in large volumes

PubMed Central

Ji, Na; Freeman, Jeremy; Smith, Spencer L.

2017-01-01

Neural circuitry has evolved to form distributed networks that act dynamically across large volumes. Collecting data from individual planes, conventional microscopy cannot sample circuitry across large volumes at the temporal resolution relevant to neural circuit function and behaviors. Here, we review emerging technologies for rapid volume imaging of neural circuitry. We focus on two critical challenges: the inertia of optical systems, which limits image speed, and aberrations, which restrict the image volume. Optical sampling time must be long enough to ensure high-fidelity measurements, but optimized sampling strategies and point spread function engineering can facilitate rapid volume imaging of neural activity within this constraint. We also discuss new computational strategies for the processing and analysis of volume imaging data of increasing size and complexity. Together, optical and computational advances are providing a broader view of neural circuit dynamics, and help elucidate how brain regions work in concert to support behavior. PMID:27571194

Construction of fuzzy spaces and their applications to matrix models

NASA Astrophysics Data System (ADS)

Abe, Yasuhiro

Quantization of spacetime by means of finite dimensional matrices is the basic idea of fuzzy spaces. There remains an issue of quantizing time, however, the idea is simple and it provides an interesting interplay of various ideas in mathematics and physics. Shedding some light on such an interplay is the main theme of this dissertation. The dissertation roughly separates into two parts. In the first part, we consider rather mathematical aspects of fuzzy spaces, namely, their construction. We begin with a review of construction of fuzzy complex projective spaces CP k (k = 1, 2, · · ·) in relation to geometric quantization. This construction facilitates defining symbols and star products on fuzzy CPk. Algebraic construction of fuzzy CPk is also discussed. We then present construction of fuzzy S 4, utilizing the fact that CP3 is an S2 bundle over S4. Fuzzy S4 is obtained by imposing an additional algebraic constraint on fuzzy CP3. Consequently it is proposed that coordinates on fuzzy S4 are described by certain block-diagonal matrices. It is also found that fuzzy S8 can analogously be constructed. In the second part of this dissertation, we consider applications of fuzzy spaces to physics. We first consider theories of gravity on fuzzy spaces, anticipating that they may offer a novel way of regularizing spacetime dynamics. We obtain actions for gravity on fuzzy S2 and on fuzzy CP3 in terms of finite dimensional matrices. Application to M(atrix) theory is also discussed. With an introduction of extra potentials to the theory, we show that it also has new brane solutions whose transverse directions are described by fuzzy S 4 and fuzzy CP3. The extra potentials can be considered as fuzzy versions of differential forms or fluxes, which enable us to discuss compactification models of M(atrix) theory. In particular, compactification down to fuzzy S4 is discussed and a realistic matrix model of M-theory in four-dimensions is proposed.

M-theoretic derivations of 4d-2d dualities: from a geometric Langlands duality for surfaces, to the AGT correspondence, to integrable systems

NASA Astrophysics Data System (ADS)

Tan, Meng-Chwan

2013-07-01

In part I, we extend our analysis in [arXiv:0807.1107], and show that a mathematically conjectured geometric Langlands duality for complex surfaces in [1], and its generalizations — which relate some cohomology of the moduli space of certain ("ramified") G-instantons to the integrable representations of the Langlands dual of certain affine (sub) G-algebras, where G is any compact Lie group — can be derived, purely physically, from the principle that the spacetime BPS spectra of string-dual M-theory compactifications ought to be equivalent. In part II, to the setup in part I, we introduce Omega-deformation via fluxbranes and add half-BPS boundary defects via M9-branes, and show that the celebrated AGT correspondence in [2, 3], and its generalizations — which essentially relate, among other things, some equivariant cohomology of the moduli space of certain ("ramified") G-instantons to the integrable representations of the Langlands dual of certain affine -algebras — can likewise be derived from the principle that the spacetime BPS spectra of string-dual M-theory compactifications ought to be equivalent. In part III, we consider various limits of our setup in part II, and connect our story to chiral fermions and integrable systems. Among other things, we derive the NekrasovOkounkov conjecture in [4] — which relates the topological string limit of the dual Nekrasov partition function for pure G to the integrable representations of the Langlands dual of an affine G-algebra — and also demonstrate that the Nekrasov-Shatashvili limit of the "fullyramified" Nekrasov instanton partition function for pure G is a simultaneous eigenfunction of the quantum Toda Hamiltonians associated with the Langlands dual of an affine G-algebra. Via the case with matter, we also make contact with Hitchin systems and the "ramified" geometric Langlands correspondence for curves.

Stroke volume variation as a guide for fluid resuscitation in patients undergoing large-volume liposuction.

PubMed

Jain, Anil Kumar; Khan, Asma M

2012-09-01

: The potential for fluid overload in large-volume liposuction is a source of serious concern. Fluid management in these patients is controversial and governed by various formulas that have been advanced by many authors. Basically, it is the ratio of what goes into the patient and what comes out. Central venous pressure has been used to monitor fluid therapy. Dynamic parameters, such as stroke volume and pulse pressure variation, are better predictors of volume responsiveness and are superior to static indicators, such as central venous pressure and pulmonary capillary wedge pressure. Stroke volume variation was used in this study to guide fluid resuscitation and compared with one guided by an intraoperative fluid ratio of 1.2 (i.e., Rohrich formula). : Stroke volume variation was used as a guide for intraoperative fluid administration in 15 patients subjected to large-volume liposuction. In another 15 patients, fluid resuscitation was guided by an intraoperative fluid ratio of 1.2. The amounts of intravenous fluid administered in the groups were compared. : The mean amount of fluid infused was 561 ± 181 ml in the stroke volume variation group and 2383 ± 1208 ml in the intraoperative fluid ratio group. The intraoperative fluid ratio when calculated for the stroke volume variation group was 0.936 ± 0.084. All patients maintained hemodynamic parameters (heart rate and systolic, diastolic, and mean blood pressure). Renal and metabolic indices remained within normal limits. : Stroke volume variation-guided fluid application could result in an appropriate amount of intravenous fluid use in patients undergoing large-volume liposuction. : Therapeutic, II.

Liposuction: Anaesthesia challenges

PubMed Central

Sood, Jayashree; Jayaraman, Lakshmi; Sethi, Nitin

2011-01-01

Liposuction is one of the most popular treatment modalities in aesthetic surgery with certain unique anaesthetic considerations. Liposuction is often performed as an office procedure. There are four main types of liposuction techniques based on the volume of infiltration or wetting solution injected, viz dry, wet, superwet, and tumescent technique. The tumescent technique is one of the most common liposuction techniques in which large volumes of dilute local anaesthetic (wetting solution) are injected into the fat to facilitate anaesthesia and decrease blood loss. The amount of lignocaine injected may be very large, approximately 35-55 mg/kg, raising concerns regarding local anaesthetic toxicity. Liposuction can be of two types according to the volume of solution aspirated: High volume (>4,000 ml aspirated) or low volume (<4,000 ml aspirated). While small volume liposuction may be done under local/monitored anaesthesia care, large-volume liposuction requires general anaesthesia. As a large volume of wetting solution is injected into the subcutaneous tissue, the intraoperative fluid management has to be carefully titrated along with haemodynamic monitoring and temperature control. Assessment of blood loss is difficult, as it is mixed with the aspirated fat. Since most obese patients opt for liposuction as a quick method to lose weight, all concerns related to obesity need to be addressed in a preoperative evaluation. PMID:21808392

On Quadratic Divergences in Supergravity, Vacuum Energy and theSupersymmetric Flavor Problem

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gaillard, Mary K.; Nelson, Brent D.

2005-11-18

We examine the phenomenological consequences ofquadratically divergent contributions to the scalar potential insupergravity effective Lagrangians. We focus specifically on the effectof these corrections on the vacuum configurationof scalar fields insoftly-broken supersymmetric theory is and the role these correctionsplay in generating non-diagonal soft scalar masses. Both effects can onlybe properly studied when the divergences are regulated in a manifestlysupersymmetric manner -- something which has ths far been neglected inpast treatments. We show how a supersymmetric regularization can impactpast conclusions about both types of phenomena and discuss what types ofhigh-energy theories are likely to be safe from unwanted flavor-changingneutral current interactions inmore » the context of supergravity theoriesderived from heterotic string compactifications.« less

Axions, inflation and the anthropic principle

NASA Astrophysics Data System (ADS)

Mack, Katherine J.

2011-07-01

The QCD axion is the leading solution to the strong-CP problem, a dark matter candidate, and a possible result of string theory compactifications. However, for axions produced before inflation, symmetry-breaking scales of fagtrsim1012 GeV (which are favored in string-theoretic axion models) are ruled out by cosmological constraints unless both the axion misalignment angle θ0 and the inflationary Hubble scale HI are extremely fine-tuned. We show that attempting to accommodate a high-fa axion in inflationary cosmology leads to a fine-tuning problem that is worse than the strong-CP problem the axion was originally invented to solve. We also show that this problem remains unresolved by anthropic selection arguments commonly applied to the high-fa axion scenario.

No-scale inflation

NASA Astrophysics Data System (ADS)

Ellis, John; Garcia, Marcos A. G.; Nanopoulos, Dimitri V.; Olive, Keith A.

2016-05-01

Supersymmetry is the most natural framework for physics above the TeV scale, and the corresponding framework for early-Universe cosmology, including inflation, is supergravity. No-scale supergravity emerges from generic string compactifications and yields a non-negative potential, and is therefore a plausible framework for constructing models of inflation. No-scale inflation yields naturally predictions similar to those of the Starobinsky model based on R+{R}2 gravity, with a tilted spectrum of scalar perturbations: {n}s∼ 0.96, and small values of the tensor-to-scalar perturbation ratio r\\lt 0.1, as favoured by Planck and other data on the cosmic microwave background (CMB). Detailed measurements of the CMB may provide insights into the embedding of inflation within string theory as well as its links to collider physics.

Aspects of string phenomenology in particle physics and cosmology

NASA Astrophysics Data System (ADS)

Antoniadis, I.

2017-12-01

I discuss possible connections between several scales in particle physics and cosmology, such the the electroweak, inflation, dark energy and Planck scales. In particular, I discuss the physics of extra dimensions and low scale gravity that are motivated from the problem of mass hierarchy, providing an alternative to low energy supersymmetry. I describe their realization in type I string theory with D-branes and I present the main experimental predictions in particle accelerators and their implications in cosmology. I also show that low-mass-scale string compactifications, with a generic D-brane configuration that realizes the Standard Model by open strings, can explain the relatively broad peak in the diphoton invariant mass spectrum at 750 GeV recently reported by the ATLAS and CMS collaborations.

Cohomology of line bundles: Applications

NASA Astrophysics Data System (ADS)

Blumenhagen, Ralph; Jurke, Benjamin; Rahn, Thorsten; Roschy, Helmut

2012-01-01

Massless modes of both heterotic and Type II string compactifications on compact manifolds are determined by vector bundle valued cohomology classes. Various applications of our recent algorithm for the computation of line bundle valued cohomology classes over toric varieties are presented. For the heterotic string, the prime examples are so-called monad constructions on Calabi-Yau manifolds. In the context of Type II orientifolds, one often needs to compute cohomology for line bundles on finite group action coset spaces, necessitating us to generalize our algorithm to this case. Moreover, we exemplify that the different terms in Batyrev's formula and its generalizations can be given a one-to-one cohomological interpretation. Furthermore, we derive a combinatorial closed form expression for two Hodge numbers of a codimension two Calabi-Yau fourfold.

Black String and Velocity Frame Dragging

NASA Astrophysics Data System (ADS)

Lee, Jungjai; Kim, Hyeong-Chan

We investigate velocity frame dragging with the boosted Schwarzschild black string solution and the boosted Kaluza-Klein bubble solution, in which a translational symmetry along the boosted z-coordinate is implemented. The velocity frame dragging effect can be nullified by the motion of an observer using the boost symmetry along the z-coordinate if it is not compact. However, in spacetime with the compact z-coordinate, we show that the effect cannot be removed since the compactification breaks the global Lorentz boost symmetry. As a result, the comoving velocity depends on r and the momentum parameter along the z-coordinate becomes an observer independent characteristic quantity of the black string and bubble solutions. The dragging induces a spherical ergo-region around the black string.

The moduli space of vacua of $$ \\mathcal{N}=2 $$ class $$ \\mathcal{S} $$ theories

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xie, Dan; Yonekura, Kazuya

We develop a systematic method to describe the moduli space of vacua of four dimensional N=2 class S theories including Coulomb branch, Higgs branch and mixed branches. In particular, we determine the Higgs and mixed branch roots, and the dimensions of the Coulomb and Higgs components of mixed branches. They are derived by using generalized Hitchin’s equations obtained from twisted compactification of 5d maximal Super-Yang-Mills, with local degrees of freedom at punctures given by (nilpotent) orbits. The crucial thing is the holomorphic factorization of the Seiberg-Witten curve and reduction of singularity at punctures. We illustrate our method by many examplesmore » including N=2 SQCD, T N theory and Argyres-Douglas theories.« less

Evidence for a bound on the lifetime of de Sitter space

NASA Astrophysics Data System (ADS)

Freivogel, Ben; Lippert, Matthew

2008-12-01

Recent work has suggested a surprising new upper bound on the lifetime of de Sitter vacua in string theory. The bound is parametrically longer than the Hubble time but parametrically shorter than the recurrence time. We investigate whether the bound is satisfied in a particular class of de Sitter solutions, the KKLT vacua. Despite the freedom to make the supersymmetry breaking scale exponentially small, which naively would lead to extremely stable vacua, we find that the lifetime is always less than about exp(1022) Hubble times, in agreement with the proposed bound. This result, however, is contingent on several estimates and assumptions; in particular, we rely on a conjectural upper bound on the Euler number of the Calabi-Yau fourfolds used in KKLT compactifications.

Consistent Pauli reduction on group manifolds

DOE PAGES

Baguet, A.; Pope, Christopher N.; Samtleben, H.

2016-01-01

We prove an old conjecture by Duff, Nilsson, Pope and Warner asserting that the NSNS sector of supergravity (and more general the bosonic string) allows for a consistent Pauli reduction on any d-dimensional group manifold G, keeping the full set of gauge bosons of the G×G isometry group of the bi-invariant metric on G. The main tool of the construction is a particular generalised Scherk–Schwarz reduction ansatz in double field theory which we explicitly construct in terms of the group's Killing vectors. Examples include the consistent reduction from ten dimensions on S3×S3 and on similar product spaces. The construction ismore » another example of globally geometric non-toroidal compactifications inducing non-geometric fluxes.« less

A simple method for the production of large volume 3D macroporous hydrogels for advanced biotechnological, medical and environmental applications

NASA Astrophysics Data System (ADS)

Savina, Irina N.; Ingavle, Ganesh C.; Cundy, Andrew B.; Mikhalovsky, Sergey V.

2016-02-01

The development of bulk, three-dimensional (3D), macroporous polymers with high permeability, large surface area and large volume is highly desirable for a range of applications in the biomedical, biotechnological and environmental areas. The experimental techniques currently used are limited to the production of small size and volume cryogel material. In this work we propose a novel, versatile, simple and reproducible method for the synthesis of large volume porous polymer hydrogels by cryogelation. By controlling the freezing process of the reagent/polymer solution, large-scale 3D macroporous gels with wide interconnected pores (up to 200 μm in diameter) and large accessible surface area have been synthesized. For the first time, macroporous gels (of up to 400 ml bulk volume) with controlled porous structure were manufactured, with potential for scale up to much larger gel dimensions. This method can be used for production of novel 3D multi-component macroporous composite materials with a uniform distribution of embedded particles. The proposed method provides better control of freezing conditions and thus overcomes existing drawbacks limiting production of large gel-based devices and matrices. The proposed method could serve as a new design concept for functional 3D macroporous gels and composites preparation for biomedical, biotechnological and environmental applications.

The origin and crust/mantle mass balance of Central Andean ignimbrite magmatism constrained by oxygen and strontium isotopes and erupted volumes

NASA Astrophysics Data System (ADS)

Freymuth, Heye; Brandmeier, Melanie; Wörner, Gerhard

2015-06-01

Volcanism during the Neogene in the Central Volcanic Zone (CVZ) of the Andes produced (1) stratovolcanoes, (2) rhyodacitic to rhyolitic ignimbrites which reach volumes of generally less than 300 km3 and (3) large-volume monotonous dacitic ignimbrites of up to several thousand cubic kilometres. We present models for the origin of these magma types using O and Sr isotopes to constrain crust/mantle proportions for the large-volume ignimbrites and explore the relationship to the evolution of the Andean crust. Oxygen isotope ratios were measured on phenocrysts in order to avoid the effects of secondary alteration. Our results show a complete overlap in the Sr-O isotope compositions of lavas from stratovolcanoes and low-volume rhyolitic ignimbrites as well as older (>9 Ma) large-volume dacitic ignimbrites. This suggests that the mass balance of crustal and mantle components are largely similar. By contrast, younger (<10 Ma) large-volume dacitic ignimbrites from the southern portion of the Central Andes have distinctly more radiogenic Sr and heavier O isotopes and thus contrast with older dacitic ignimbrites in northernmost Chile and southern Peru. Results of assimilation and fractional crystallization (AFC) models show that the largest chemical changes occur in the lower crust where magmas acquire a base-level geochemical signature that is later modified by middle to upper crustal AFC. Using geospatial analysis, we estimated the volume of these ignimbrite deposits throughout the Central Andes during the Neogene and examined the spatiotemporal pattern of so-called ignimbrite flare-ups. We observe a N-S migration of maximum ages of the onset of large-volume "ignimbrite pulses" through time: Major pulses occurred at 19-24 Ma (e.g. Oxaya, Nazca Group), 13-14 Ma (e.g. Huaylillas and Altos de Pica ignimbrites) and <10 Ma (Altiplano and Puna ignimbrites). Such "flare-ups" represent magmatic production rates of 25 to >70 km3 Ma-1 km-1 (assuming plutonic/volcanic ratios of 1:5) which are additional to, but within the order of, the arc background magmatic flux. Comparing our results to average shortening rates observed in the Andes, we observe a "lag-time" with large-volume eruptions occurring after accelerated shortening. A similar delay exists between the ignimbrite pulses and the subduction of the Juan Fernandez ridge. This is consistent with the idea that large-volume ignimbrite eruptions occurred in the wake of the N-S passage of the ridge after slab steepening has allowed hot asthenospheric mantle to ascend into and cause the melting of the mantle wedge. In our model, the older large-volume dacitic ignimbrites in the northern part of the CVZ have lower (15-37 %) crustal contributions because they were produced at times when the Central Andean crust was thinner and colder, and large-scale melting in the middle crust could not be achieved. Younger ignimbrite flare-ups further south (<10 Ma, >22°S) formed with a significantly higher crustal contribution (22-68 %) because at that time the Andean crust was thicker and hotter and, therefore primed for more extensive crustal melting. The rhyolitic lower-volume ignimbrites are more equally distributed in the CVZ in time and space and are produced by mechanisms similar to those operating below large stratovolcanoes, but at times of higher melt fluxes from the mantle wedge.

Recurrence interval analysis of trading volumes

NASA Astrophysics Data System (ADS)

Ren, Fei; Zhou, Wei-Xing

2010-06-01

We study the statistical properties of the recurrence intervals τ between successive trading volumes exceeding a certain threshold q . The recurrence interval analysis is carried out for the 20 liquid Chinese stocks covering a period from January 2000 to May 2009, and two Chinese indices from January 2003 to April 2009. Similar to the recurrence interval distribution of the price returns, the tail of the recurrence interval distribution of the trading volumes follows a power-law scaling, and the results are verified by the goodness-of-fit tests using the Kolmogorov-Smirnov (KS) statistic, the weighted KS statistic and the Cramér-von Mises criterion. The measurements of the conditional probability distribution and the detrended fluctuation function show that both short-term and long-term memory effects exist in the recurrence intervals between trading volumes. We further study the relationship between trading volumes and price returns based on the recurrence interval analysis method. It is found that large trading volumes are more likely to occur following large price returns, and the comovement between trading volumes and price returns is more pronounced for large trading volumes.

Recurrence interval analysis of trading volumes.

PubMed

Ren, Fei; Zhou, Wei-Xing

2010-06-01

We study the statistical properties of the recurrence intervals τ between successive trading volumes exceeding a certain threshold q. The recurrence interval analysis is carried out for the 20 liquid Chinese stocks covering a period from January 2000 to May 2009, and two Chinese indices from January 2003 to April 2009. Similar to the recurrence interval distribution of the price returns, the tail of the recurrence interval distribution of the trading volumes follows a power-law scaling, and the results are verified by the goodness-of-fit tests using the Kolmogorov-Smirnov (KS) statistic, the weighted KS statistic and the Cramér-von Mises criterion. The measurements of the conditional probability distribution and the detrended fluctuation function show that both short-term and long-term memory effects exist in the recurrence intervals between trading volumes. We further study the relationship between trading volumes and price returns based on the recurrence interval analysis method. It is found that large trading volumes are more likely to occur following large price returns, and the comovement between trading volumes and price returns is more pronounced for large trading volumes.

Endoclips vs large or small-volume epinephrine in peptic ulcer recurrent bleeding

PubMed Central

Ljubicic, Neven; Budimir, Ivan; Biscanin, Alen; Nikolic, Marko; Supanc, Vladimir; Hrabar, Davor; Pavic, Tajana

2012-01-01

AIM: To compare the recurrent bleeding after endoscopic injection of different epinephrine volumes with hemoclips in patients with bleeding peptic ulcer. METHODS: Between January 2005 and December 2009, 150 patients with gastric or duodenal bleeding ulcer with major stigmata of hemorrhage and nonbleeding visible vessel in an ulcer bed (Forrest IIa) were included in the study. Patients were randomized to receive a small-volume epinephrine group (15 to 25 mL injection group; Group 1, n = 50), a large-volume epinephrine group (30 to 40 mL injection group; Group 2, n = 50) and a hemoclip group (Group 3, n = 50). The rate of recurrent bleeding, as the primary outcome, was compared between the groups of patients included in the study. Secondary outcomes compared between the groups were primary hemostasis rate, permanent hemostasis, need for emergency surgery, 30 d mortality, bleeding-related deaths, length of hospital stay and transfusion requirements. RESULTS: Initial hemostasis was obtained in all patients. The rate of early recurrent bleeding was 30% (15/50) in the small-volume epinephrine group (Group 1) and 16% (8/50) in the large-volume epinephrine group (Group 2) (P = 0.09). The rate of recurrent bleeding was 4% (2/50) in the hemoclip group (Group 3); the difference was statistically significant with regard to patients treated with either small-volume or large-volume epinephrine solution (P = 0.0005 and P = 0.045, respectively). Duration of hospital stay was significantly shorter among patients treated with hemoclips than among patients treated with epinephrine whereas there were no differences in transfusion requirement or even 30 d mortality between the groups. CONCLUSION: Endoclip is superior to both small and large volume injection of epinephrine in the prevention of recurrent bleeding in patients with peptic ulcer. PMID:22611315

Sewage sludge pasteurization by gamma radiation: Financial viability case studies

NASA Astrophysics Data System (ADS)

Swinwood, Jean F.; Kotler, Jiri

This paper examines the financial viability of sewage sludge pasteurization by gamma radiation, by examining the following three North American scenarios: 1) Small volume sewage treatment plant experiencing high sludge disposal costs. 2) Large volume sewage treatment plant experiencing low sludge disposal costs. 3) Large volume sewage treatment plant experiencing high sludge disposal costs.

Effect of cold drawing ratio on γ′ precipitation in Inconel X-750

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ha, Jeong Won; Research and Development Center, KOS Limited, Yangsan 626-230; Seong, Baek Seok

2014-10-15

Inconel X-750 is a Ni-based precipitation-hardened superalloy having large tensile and fracture strengths. In the study, X-750 wires were cold drawn to different extents. Small angle neutron scattering was employed to quantitatively measure the size and volume fraction of the γ′ phase as a function of the cold drawing ratio (DR) and aging temperature. The presence and size of γ′ precipitates were confirmed by transmission electron microscopy. The drawing ratio had an important effect on the volume fraction of the γ′ precipitates. However, the size of the precipitates was independent on the drawing ratio. The specimen with the minimum drawingmore » ratio (DR0) produced the largest volume fraction of γ′ as compared with large drawing ratio (DR) specimens such as DR17 and DR42. The small volume fraction of the γ′ phase for a sizeable drawing ratio was associated with the large amount of nucleation sites for secondary carbides, M{sub 23}C{sub 6}, and the fast diffusion path, i.e., dislocation, needed to form M{sub 23}C{sub 6}. A Cr depletion zone around the secondary carbides raised the solubility of γ′. Therefore, the significant drawing ratio contributing to the large volume fraction of the secondary carbides decreased the volume fraction of the γ′ precipitates in Inconel X-750. - Highlights: • The volume fraction of secondary carbides increased with the drawing ratio. • The volume fraction of γ′ decreased as the drawing ratio increased. • The drawing ratio affected the γ′ volume fraction with no variation of the γ' size. • The volume fraction of γ′ was affected by the secondary carbide volume fraction.« less

A simple method for the production of large volume 3D macroporous hydrogels for advanced biotechnological, medical and environmental applications

PubMed Central

Savina, Irina N.; Ingavle, Ganesh C.; Cundy, Andrew B.; Mikhalovsky, Sergey V.

2016-01-01

The development of bulk, three-dimensional (3D), macroporous polymers with high permeability, large surface area and large volume is highly desirable for a range of applications in the biomedical, biotechnological and environmental areas. The experimental techniques currently used are limited to the production of small size and volume cryogel material. In this work we propose a novel, versatile, simple and reproducible method for the synthesis of large volume porous polymer hydrogels by cryogelation. By controlling the freezing process of the reagent/polymer solution, large-scale 3D macroporous gels with wide interconnected pores (up to 200 μm in diameter) and large accessible surface area have been synthesized. For the first time, macroporous gels (of up to 400 ml bulk volume) with controlled porous structure were manufactured, with potential for scale up to much larger gel dimensions. This method can be used for production of novel 3D multi-component macroporous composite materials with a uniform distribution of embedded particles. The proposed method provides better control of freezing conditions and thus overcomes existing drawbacks limiting production of large gel-based devices and matrices. The proposed method could serve as a new design concept for functional 3D macroporous gels and composites preparation for biomedical, biotechnological and environmental applications. PMID:26883390

Novel diamond cells for neutron diffraction using multi-carat CVD anvils.

PubMed

Boehler, R; Molaison, J J; Haberl, B

2017-08-01

Traditionally, neutron diffraction at high pressure has been severely limited in pressure because low neutron flux required large sample volumes and therefore large volume presses. At the high-flux Spallation Neutron Source at the Oak Ridge National Laboratory, we have developed new, large-volume diamond anvil cells for neutron diffraction. The main features of these cells are multi-carat, single crystal chemical vapor deposition diamonds, very large diffraction apertures, and gas membranes to accommodate pressure stability, especially upon cooling. A new cell has been tested for diffraction up to 40 GPa with an unprecedented sample volume of ∼0.15 mm 3 . High quality spectra were obtained in 1 h for crystalline Ni and in ∼8 h for disordered glassy carbon. These new techniques will open the way for routine megabar neutron diffraction experiments.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Parthipun, A. A., E-mail: aneeta@hotmail.co.uk; Taylor, J.; Manyonda, I.

The purpose of this study was to determine whether there is a correlation between large uterine fibroid diameter, uterine volume, number of vials of embolic agent used and risk of complications from uterine artery embolisation (UAE). This was a prospective study involving 121 patients undergoing UAE embolisation for symptomatic uterine fibroids at a single institution. Patients were grouped according to diameter of largest fibroid and uterine volume. Results were also stratified according to the number of vials of embolic agent used and rate of complications. No statistical difference in complication rate was demonstrated between the two groups according to diametermore » of the largest fibroid (large fibroids were classified as {>=}10 cm; Fisher's exact test P = 1.00), and no statistical difference in complication rate was demonstrated according to uterine volume (large uterine volume was defined as {>=}750 cm{sup 3}; Fisher's exact test P = 0.70). 84 of the 121 patients had documentation of the number of vials used during the procedure. Patients were divided into two groups, with {>=}4 used defined as a large number of embolic agent. There was no statistical difference between these two groups and no associated increased risk of developing complications. This study showed no increased incidence of complications in women with large-diameter fibroids or uterine volumes as defined. In addition, there was no evidence of increased complications according to quantity of embolic material used. Therefore, UAE should be offered to women with large fibroids and uterine volumes.« less

Public-Private Partnership: Joint recommendations to improve downloads of large Earth observation data

NASA Astrophysics Data System (ADS)

Ramachandran, R.; Murphy, K. J.; Baynes, K.; Lynnes, C.

2016-12-01

With the volume of Earth observation data expanding rapidly, cloud computing is quickly changing the way Earth observation data is processed, analyzed, and visualized. The cloud infrastructure provides the flexibility to scale up to large volumes of data and handle high velocity data streams efficiently. Having freely available Earth observation data collocated on a cloud infrastructure creates opportunities for innovation and value-added data re-use in ways unforeseen by the original data provider. These innovations spur new industries and applications and spawn new scientific pathways that were previously limited due to data volume and computational infrastructure issues. NASA, in collaboration with Amazon, Google, and Microsoft, have jointly developed a set of recommendations to enable efficient transfer of Earth observation data from existing data systems to a cloud computing infrastructure. The purpose of these recommendations is to provide guidelines against which all data providers can evaluate existing data systems and be used to improve any issues uncovered to enable efficient search, access, and use of large volumes of data. Additionally, these guidelines ensure that all cloud providers utilize a common methodology for bulk-downloading data from data providers thus preventing the data providers from building custom capabilities to meet the needs of individual cloud providers. The intent is to share these recommendations with other Federal agencies and organizations that serve Earth observation to enable efficient search, access, and use of large volumes of data. Additionally, the adoption of these recommendations will benefit data users interested in moving large volumes of data from data systems to any other location. These data users include the cloud providers, cloud users such as scientists, and other users working in a high performance computing environment who need to move large volumes of data.

Assessing the Feasibility of Large-Scale Countercyclical Public Job-Creation. Final Report, Volume III. Selected Implications of Public Job-Creation.

ERIC Educational Resources Information Center

Urban Inst., Washington, DC.

This last of a three-volume report of a study done to assess the feasibility of large-scale, countercyclical public job creation covers the findings regarding the priorities among projects, indirect employment effects, skill imbalances, and administrative issues; and summarizes the overall findings, conclusions, and recommendations. (Volume 1,…

Combined low-volume polyethylene glycol solution plus stimulant laxatives versus standard-volume polyethylene glycol solution: A prospective, randomized study of colon cleansing before colonoscopy

PubMed Central

Hookey, Lawrence C; Depew, William T; Vanner, Stephen J

2006-01-01

INTRODUCTION The effectiveness of polyethylene glycol solutions (PEG) for colon cleansing is often limited by the inability of patients to drink adequate portions of the 4 L solution. The aim of the present study was to determine whether a reduced volume of PEG combined with stimulant laxatives would be better tolerated and as or more effective than the standard dose. METHODS Patients undergoing outpatient colonoscopy were randomly assigned to receive either low-volume PEG plus sennosides (120 mg oral sennosides syrup followed by 2 L PEG) or the standard volume preparation (4 L PEG). The subjects rated the tolerability of the preparations and their symptoms. Colonoscopists were blind to the colonic cleansing preparation and graded the cleansing efficacy using a validated tool (the Ottawa scale). RESULTS The low-volume PEG plus sennosides preparation was significantly better tolerated than the standard large volume PEG (P<0.001) but was less efficacious (P=0.03). Thirty-eight per cent of patients in the large volume PEG group were unable to finish the preparation, compared with only 6% in the reduced volume group. There were no adverse events reported. CONCLUSIONS Although the low-volume PEG plus sennosides preparation was better tolerated, it was not as effective as standard large-volume PEG. However, in view of the significant difference in tolerance, further research investigating possible improvements in the reduced-volume regimen seems warranted. PMID:16482236

Availability and temporal heterogeneity of water supply affect the vertical distribution and mortality of a belowground herbivore and consequently plant growth.

PubMed

Tsunoda, Tomonori; Kachi, Naoki; Suzuki, Jun-Ichirou

2014-01-01

We examined how the volume and temporal heterogeneity of water supply changed the vertical distribution and mortality of a belowground herbivore, and consequently affected plant biomass. Plantago lanceolata (Plantaginaceae) seedlings were grown at one per pot under different combinations of water volume (large or small volume) and heterogeneity (homogeneous water conditions, watered every day; heterogeneous conditions, watered every 4 days) in the presence or absence of a larva of the belowground herbivorous insect, Anomala cuprea (Coleoptera: Scarabaeidae). The larva was confined in different vertical distributions to top feeding zone (top treatment), middle feeding zone (middle treatment), or bottom feeding zone (bottom treatment); alternatively no larva was introduced (control treatment) or larval movement was not confined (free treatment). Three-way interaction between water volume, heterogeneity, and the herbivore significantly affected plant biomass. With a large water volume, plant biomass was lower in free treatment than in control treatment regardless of heterogeneity. Plant biomass in free treatment was as low as in top treatment. With a small water volume and in free treatment, plant biomass was low (similar to that under top treatment) under homogeneous water conditions but high under heterogeneous ones (similar to that under middle or bottom treatment). Therefore, there was little effect of belowground herbivory on plant growth under heterogeneous water conditions. In other watering regimes, herbivores would be distributed in the shallow soil and reduced root biomass. Herbivore mortality was high with homogeneous application of a large volume or heterogeneous application of a small water volume. Under the large water volume, plant biomass was high in pots in which the herbivore had died. Thus, the combinations of water volume and heterogeneity affected plant growth via the change of a belowground herbivore.

Novel diamond cells for neutron diffraction using multi-carat CVD anvils

DOE PAGES

Boehler, R.; Molaison, J. J.; Haberl, B.

2017-08-17

Traditionally, neutron diffraction at high pressure has been severely limited in pressure because low neutron flux required large sample volumes and therefore large volume presses. At the high-flux Spallation Neutron Source at the Oak Ridge National Laboratory, we have developed in this paper new, large-volume diamond anvil cells for neutron diffraction. The main features of these cells are multi-carat, single crystal chemical vapor deposition diamonds, very large diffraction apertures, and gas membranes to accommodate pressure stability, especially upon cooling. A new cell has been tested for diffraction up to 40 GPa with an unprecedented sample volume of ~0.15 mm 3.more » High quality spectra were obtained in 1 h for crystalline Ni and in ~8 h for disordered glassy carbon. Finally, these new techniques will open the way for routine megabar neutron diffraction experiments.« less

Radiation from Large Gas Volumes and Heat Exchange in Steam Boiler Furnaces

DOE Office of Scientific and Technical Information (OSTI.GOV)

Makarov, A. N., E-mail: tgtu-kafedra-ese@mail.ru

2015-09-15

Radiation from large cylindrical gas volumes is studied as a means of simulating the flare in steam boiler furnaces. Calculations of heat exchange in a furnace by the zonal method and by simulation of the flare with cylindrical gas volumes are described. The latter method is more accurate and yields more reliable information on heat transfer processes taking place in furnaces.

U-folds as K3 fibrations

NASA Astrophysics Data System (ADS)

Braun, Andreas P.; Fucito, Francesco; Morales, Jose Francisco

2013-10-01

We study four-dimensional flux vacua describing intrinsic non- perturbative systems of 3 and 7 branes in type IIB string theory. The solutions are described as compactifications of a G(ravity) theory on a Calabi Yau threefold which consists of a fibration of an auxiliary K3 surface over an S 2 base. In the spirit of F-theory, the complex structure of the K3 surface varying over the base codifies the details of the fluxes, the dilaton and the warp factors in type IIB string theory. We discuss in detail some simple examples of geometric and non-geometric solutions where the precise flux/geometry dictionary can be explicitly worked out. In particular, we describe non-geometric T-fold solutions exhibiting non-trivial T-duality monodromies exchanging 3- and 7-branes.

Cosmic infinity: a dynamical system approach

NASA Astrophysics Data System (ADS)

Bouhmadi-López, Mariam; Marto, João; Morais, João; Silva, César M.

2017-03-01

Dynamical system techniques are extremely useful to study cosmology. It turns out that in most of the cases, we deal with finite isolated fixed points corresponding to a given cosmological epoch. However, it is equally important to analyse the asymptotic behaviour of the universe. On this paper, we show how this can be carried out for 3-form models. In fact, we show that there are fixed points at infinity mainly by introducing appropriate compactifications and defining a new time variable that washes away any potential divergence of the system. The richness of 3-form models allows us as well to identify normally hyperbolic non-isolated fixed points. We apply this analysis to three physically interesting situations: (i) a pre-inflationary era; (ii) an inflationary era; (iii) the late-time dark matter/dark energy epoch.

Massive quiver matrix models for massive charged particles in AdS

DOE PAGES

Asplund, Curtis T.; Denef, Frederik; Dzienkowski, Eric

2016-01-11

Here, we present a new class of N = 4 supersymmetric quiver matrix models and argue that it describes the stringy low-energy dynamics of internally wrapped D-branes in four-dimensional anti-de Sitter (AdS) flux compactifications. The Lagrangians of these models differ from previously studied quiver matrix models by the presence of mass terms, associated with the AdS gravitational potential, as well as additional terms dictated by supersymmetry. These give rise to dynamical phenomena typically associated with the presence of fluxes, such as fuzzy membranes, internal cyclotron motion and the appearance of confining strings. We also show how these models can bemore » obtained by dimensional reduction of four-dimensional supersymmetric quiver gauge theories on a three-sphere.« less

Interaction of moving branes with background massless and tachyon fields in superstring theory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rezaei, Z., E-mail: z.rezaei@aut.ac.ir; Kamani, D., E-mail: kamani@aut.ac.ir

2012-02-15

Using the boundary state formalism, we study a moving Dp-brane in a partially compact space-time in the presence of background fields: the Kalb-Ramond field B{sub {mu}{nu}}, a U(1) gauge field A{sub {alpha}}, and the tachyon field. The boundary state enables us to obtain the interaction amplitude of two branes with the above back-ground fields. The branes are parallel or perpendicular to each other. Because of the presence of background fields, compactification of some space-time directions, motion of the branes, and the arbitrariness of the dimensions of the branes, the system is rather general. Due to the tachyon fields and velocitiesmore » of the branes, the behavior of the interaction amplitude reveals obvious differences from the conventional behavior.« less

The hypermultiplet with Heisenberg isometry in N = 2 global and local supersymmetry

NASA Astrophysics Data System (ADS)

Ambrosetti, Nicola; Antoniadis, Ignatios; Derendinger, Jean-Pierre; Tziveloglou, Pantelis

2011-06-01

The string coupling of N = 2 supersymmetric compactifications of type II string theory on a Calabi-Yau manifold belongs to the so-called universal dilaton hyper-multiplet, that has four real scalars living on a quaternion-Kähler manifold. Requiring Heisenberg symmetry, which is a maximal subgroup of perturbative isometries, reduces the possible manifolds to a one-parameter family that describes the tree-level effective action deformed by the only possible perturbative correction arising at one-loop level. A similar argument can be made at the level of global supersymmetry where the scalar manifold is hyper-Kähler. In this work, the connection between global and local supersymmetry is explicitly constructed, providing a non-trivial gravity decoupled limit of type II strings already in perturbation theory.

R-charge conservation and more in factorizable and non-factorizable orbifolds

NASA Astrophysics Data System (ADS)

Bizet, Nana G. Cabo; Kobayashi, Tatsuo; Peña, Damián K. Mayorga; Parameswaran, Susha L.; Schmitz, Matthias; Zavala, Ivonne

2013-05-01

We consider the string theory origin of R-charge conservation laws in heterotic orbifold compactifications, deriving the corresponding string coupling selection rule for factorizable and non-factorizable orbifolds, with prime ordered and non-prime ordered point groups. R-charge conservation arises due to symmetries among the worldsheet instantons that can mediate the couplings. Among our results is a previously missed non-trivial contribution to the conserved R-charges from the γ-phases in non-prime orbifolds, which weakens the R-charge selection rule. Symmetries among the worldsheet instantons can also lead to additional selection rules for some couplings. We make a similar analysis for Rule 4 or the "torus lattice selection rule". Moreover, we identify a new string selection rule, that we call Rule 6 or the "coset vector selection rule".

Introduction to sporadic groups for physicists

NASA Astrophysics Data System (ADS)

Boya, Luis J.

2013-04-01

We describe the collection of finite simple groups, with a view to physical applications. We recall first the prime cyclic groups Zp and the alternating groups Altn > 4. After a quick revision of finite fields {F}_q, q = pf, with p prime, we consider the 16 families of finite simple groups of Lie type. There are also 26 extra ‘sporadic’ groups, which gather in three interconnected ‘generations’ (with 5+7+8 groups) plus the pariah groups (6). We point out a couple of physical applications, including constructing the biggest sporadic group, the ‘Monster’ group, with close to 1054 elements from arguments of physics, and also the relation of some Mathieu groups with compactification in string and M-theory. This article is dedicated to the memory of Juan Sancho Guimerá.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Birkedal-Hansen, A.; Binetruy, P.; Mambrini, Y.

We provide a detailed study of the phenomenology of orbifold compactifications of the heterotic string within the context of supergravity effective theories. Our investigation focuses on those models where the soft Lagrangian is dominated by loop contributions to the various soft supersymmetry breaking parameters. Such models typically predict non-universal soft masses and are thus significantly different from minimal supergravity and other universal models. We consider the pattern of masses that are governed by these soft terms and investigate the implications of certain indirect constraints on supersymmetric models, such as flavor-changing neutral currents, the anomalous magnetic moment of the muon andmore » the density of thermal relic neutralinos. These string-motivated models show novel behavior that interpolates between the phenomenology of unified supergravity models and models dominated by the superconformal anomaly.« less

Generalised solutions for fully nonlinear PDE systems and existence-uniqueness theorems

NASA Astrophysics Data System (ADS)

Katzourakis, Nikos

2017-07-01

We introduce a new theory of generalised solutions which applies to fully nonlinear PDE systems of any order and allows for merely measurable maps as solutions. This approach bypasses the standard problems arising by the application of Distributions to PDEs and is not based on either integration by parts or on the maximum principle. Instead, our starting point builds on the probabilistic representation of derivatives via limits of difference quotients in the Young measures over a toric compactification of the space of jets. After developing some basic theory, as a first application we consider the Dirichlet problem and we prove existence-uniqueness-partial regularity of solutions to fully nonlinear degenerate elliptic 2nd order systems and also existence of solutions to the ∞-Laplace system of vectorial Calculus of Variations in L∞.

Five-dimensional gauge theory and compactification on a torus

NASA Astrophysics Data System (ADS)

Haghighat, Babak; Vandoren, Stefan

2011-09-01

We study five-dimensional minimally supersymmetric gauge theory compactified on a torus down to three dimensions, and its embedding into string/M-theory using geometric engineering. The moduli space on the Coulomb branch is hyperkähler equipped with a metric with modular transformation properties. We determine the one-loop corrections to the metric and show that they can be interpreted as worldsheet and D1-brane instantons in type IIB string theory. Furthermore, we analyze instanton corrections coming from the solitonic BPS magnetic string wrapped over the torus. In particular, we show how to compute the path-integral for the zero-modes from the partition function of the M5 brane, or, using a 2d/4d correspondence, from the partition function of N=4 SYM theory on a Hirzebruch surface.

Feasibility of large volume tumor ablation using multiple-mode strategy with fast scanning method: A numerical study

NASA Astrophysics Data System (ADS)

Wu, Hao; Shen, Guofeng; Qiao, Shan; Chen, Yazhu

2017-03-01

Sonication with fast scanning method can generate homogeneous lesions without complex planning. But when the target region is large, switching focus too fast will reduce the heat accumulation, the margin of which may not ablated. Furthermore, high blood perfusion rate will reduce this maximum volume that can be ablated. Therefore, fast scanning method may not be applied to large volume tumor. To expand the therapy scope, this study combines the fast scan method with multiple mode strategy. Through simulation and experiment, the feasibility of this new strategy is evaluated and analyzed.

Dependence of the clustering properties of galaxies on stellar velocity dispersion in the Main galaxy sample of SDSS DR10

NASA Astrophysics Data System (ADS)

Deng, Xin-Fa; Song, Jun; Chen, Yi-Qing; Jiang, Peng; Ding, Ying-Ping

2014-08-01

Using two volume-limited Main galaxy samples of the Sloan Digital Sky Survey Data Release 10 (SDSS DR10), we investigate the dependence of the clustering properties of galaxies on stellar velocity dispersion by cluster analysis. It is found that in the luminous volume-limited Main galaxy sample, except at r=1.2, richer and larger systems can be more easily formed in the large stellar velocity dispersion subsample, while in the faint volume-limited Main galaxy sample, at r≥0.9, an opposite trend is observed. According to statistical analyses of the multiplicity functions, we conclude in two volume-limited Main galaxy samples: small stellar velocity dispersion galaxies preferentially form isolated galaxies, close pairs and small group, while large stellar velocity dispersion galaxies preferentially inhabit the dense groups and clusters. However, we note the difference between two volume-limited Main galaxy samples: in the faint volume-limited Main galaxy sample, at r≥0.9, the small stellar velocity dispersion subsample has a higher proportion of galaxies in superclusters ( n≥200) than the large stellar velocity dispersion subsample.

Prototypic Development and Evaluation of a Medium Format Metric Camera

NASA Astrophysics Data System (ADS)

Hastedt, H.; Rofallski, R.; Luhmann, T.; Rosenbauer, R.; Ochsner, D.; Rieke-Zapp, D.

2018-05-01

Engineering applications require high-precision 3D measurement techniques for object sizes that vary between small volumes (2-3 m in each direction) and large volumes (around 20 x 20 x 1-10 m). The requested precision in object space (1σ RMS) is defined to be within 0.1-0.2 mm for large volumes and less than 0.01 mm for small volumes. In particular, focussing large volume applications the availability of a metric camera would have different advantages for several reasons: 1) high-quality optical components and stabilisations allow for a stable interior geometry of the camera itself, 2) a stable geometry leads to a stable interior orientation that enables for an a priori camera calibration, 3) a higher resulting precision can be expected. With this article the development and accuracy evaluation of a new metric camera, the ALPA 12 FPS add|metric will be presented. Its general accuracy potential is tested against calibrated lengths in a small volume test environment based on the German Guideline VDI/VDE 2634.1 (2002). Maximum length measurement errors of less than 0.025 mm are achieved with different scenarios having been tested. The accuracy potential for large volumes is estimated within a feasibility study on the application of photogrammetric measurements for the deformation estimation on a large wooden shipwreck in the German Maritime Museum. An accuracy of 0.2 mm-0.4 mm is reached for a length of 28 m (given by a distance from a lasertracker network measurement). All analyses have proven high stabilities of the interior orientation of the camera and indicate the applicability for a priori camera calibration for subsequent 3D measurements.

A Natural Extension of Standard Warped Higher-Dimensional Compactifications: Theory and Phenomenology

NASA Astrophysics Data System (ADS)

Hong, Sungwoo

Warped higher-dimensional compactifications with "bulk'' standard model, or their AdS/CFT dual as the purely 4D scenario of Higgs compositeness and partial compositeness, offer an elegant approach to resolving the electroweak hierarchy problem as well as the origins of flavor structure. However, low-energy electroweak/flavor/CP constraints and the absence of non-standard physics at LHC Run 1 suggest that a "little hierarchy problem'' remains, and that the new physics underlying naturalness may lie out of LHC reach. Assuming this to be the case, we show that there is a simple and natural extension of the minimal warped model in the Randall-Sundrum framework, in which matter, gauge and gravitational fields propagate modestly different degrees into the IR of the warped dimension, resulting in rich and striking consequences for the LHC (and beyond). The LHC-accessible part of the new physics is AdS/CFT dual to the mechanism of "vectorlike confinement'', with TeV-scale Kaluza-Klein excitations of the gauge and gravitational fields dual to spin-0,1,2 composites. Unlike the minimal warped model, these low-lying excitations have predominantly flavor-blind and flavor/CP-safe interactions with the standard model. In addition, the usual leading decay modes of the lightest KK gauge bosons into top and Higgs bosons are suppressed. This effect permits erstwhile subdominant channels to become significant. These include flavor-universal decays to all pairs of SM fermions, and a novel channel--decay to a radion and a SM gauge boson, followed by radion decay to a pair of SM gauge bosons. We present a detailed phenomenological study of the latter cascade decay processes. Remarkably, this scenario also predicts small deviations from flavor-blindness originating from virtual effects of Higgs/top compositeness at O(10) TeV, with subdominant resonance decays into a pair of Higgs/top-rich final states, giving the LHC an early "preview'' of the nature of the resolution of the hierarchy problem. Discoveries of this type at LHC Run 2 would thereby anticipate (and set a target for) even more explicit explorations of Higgs compositeness at a 100 TeV collider, or for next-generation flavor tests.

Reuse of Concentrated Animal Feeding Operating Wastewater on Agricultural Lands

EPA Science Inventory

Concentrated animal feeding operations (CAFOs) generate large volumes of manure and manure-contaminated wash and runoff water. Transportation, storage, and treatment of manure and manure-contaminated water are costly. The large volume of waste generated, and the lack of disposal ...

Geophysics Under Pressure: Large-Volume Presses Versus the Diamond-Anvil Cell

NASA Astrophysics Data System (ADS)

Hazen, R. M.

2002-05-01

Prior to 1970, the legacy of Harvard physicist Percy Bridgman dominated high-pressure geophysics. Massive presses with large-volume devices, including piston-cylinder, opposed-anvil, and multi-anvil configurations, were widely used in both science and industry to achieve a range of crustal and upper mantle temperatures and pressures. George Kennedy of UCLA was a particularly influential advocate of large-volume apparatus for geophysical research prior to his death in 1980. The high-pressure scene began to change in 1959 with the invention of the diamond-anvil cell, which was designed simultaneously and independently by John Jamieson at the University of Chicago and Alvin Van Valkenburg at the National Bureau of Standards in Washington, DC. The compact, inexpensive diamond cell achieved record static pressures and had the advantage of optical access to the high-pressure environment. Nevertheless, members of the geophysical community, who favored the substantial sample volumes, geothermally relevant temperature range, and satisfying bulk of large-volume presses, initially viewed the diamond cell with indifference or even contempt. Several factors led to a gradual shift in emphasis from large-volume presses to diamond-anvil cells in geophysical research during the 1960s and 1970s. These factors include (1) their relatively low cost at time of fiscal restraint, (2) Alvin Van Valkenburg's new position as a Program Director at the National Science Foundation in 1964 (when George Kennedy's proposal for a Nation High-Pressure Laboratory was rejected), (3) the development of lasers and micro-analytical spectroscopic techniques suitable for analyzing samples in a diamond cell, and (4) the attainment of record pressures (e.g., 100 GPa in 1975 by Mao and Bell at the Geophysical Laboratory). Today, a more balanced collaborative approach has been adopted by the geophysics and mineral physics community. Many high-pressure laboratories operate a new generation of less expensive large-volume presses side-by-side with a wide variety of diamond-anvil cells.

Standard error of estimated average timber volume per acre under point sampling when trees are measured for volume on a subsample of all points.

Treesearch

Floyd A. Johnson

1961-01-01

This report assumes a knowledge of the principles of point sampling as described by Grosenbaugh, Bell and Alexander, and others. Whenever trees are counted at every point in a sample of points (large sample) and measured for volume at a portion (small sample) of these points, the sampling design could be called ratio double sampling. If the large...

Evaluation of Bacillus oleronius as a Biological Indicator for Terminal Sterilization of Large-Volume Parenterals.

PubMed

Izumi, Masamitsu; Fujifuru, Masato; Okada, Aki; Takai, Katsuya; Takahashi, Kazuhiro; Udagawa, Takeshi; Miyake, Makoto; Naruyama, Shintaro; Tokuda, Hiroshi; Nishioka, Goro; Yoden, Hikaru; Aoki, Mitsuo

2016-01-01

In the production of large-volume parenterals in Japan, equipment and devices such as tanks, pipework, and filters used in production processes are exhaustively cleaned and sterilized, and the cleanliness of water for injection, drug materials, packaging materials, and manufacturing areas is well controlled. In this environment, the bioburden is relatively low, and less heat resistant compared with microorganisms frequently used as biological indicators such as Geobacillus stearothermophilus (ATCC 7953) and Bacillus subtilis 5230 (ATCC 35021). Consequently, the majority of large-volume parenteral solutions in Japan are manufactured under low-heat sterilization conditions of F0 <2 min, so that loss of clarity of solutions and formation of degradation products of constituents are minimized. Bacillus oleronius (ATCC 700005) is listed as a biological indicator in "Guidance on the Manufacture of Sterile Pharmaceutical Products Produced by Terminal Sterilization" (guidance in Japan, issued in 2012). In this study, we investigated whether B. oleronius is an appropriate biological indicator of the efficacy of low-heat, moist-heat sterilization of large-volume parenterals. Specifically, we investigated the spore-forming ability of this microorganism in various cultivation media and measured the D-values and z-values as parameters of heat resistance. The D-values and z-values changed depending on the constituents of large-volume parenteral products. Also, the spores from B. oleronius showed a moist-heat resistance that was similar to or greater than many of the spore-forming organisms isolated from Japanese parenteral manufacturing processes. Taken together, these results indicate that B. oleronius is suitable as a biological indicator for sterility assurance of large-volume parenteral solutions subjected to low-heat, moist-heat terminal sterilization. © PDA, Inc. 2016.

Antarctic icebergs distributions 1992-2014

NASA Astrophysics Data System (ADS)

Tournadre, J.; Bouhier, N.; Girard-Ardhuin, F.; Rémy, F.

2016-01-01

Basal melting of floating ice shelves and iceberg calving constitute the two almost equal paths of freshwater flux between the Antarctic ice cap and the Southern Ocean. The largest icebergs (>100 km2) transport most of the ice volume but their basal melting is small compared to their breaking into smaller icebergs that constitute thus the major vector of freshwater. The archives of nine altimeters have been processed to create a database of small icebergs (<8 km2) within open water containing the positions, sizes, and volumes spanning the 1992-2014 period. The intercalibrated monthly ice volumes from the different altimeters have been merged in a homogeneous 23 year climatology. The iceberg size distribution, covering the 0.1-10,000 km2 range, estimated by combining small and large icebergs size measurements follows well a power law of slope -1.52 ± 0.32 close to the -3/2 laws observed and modeled for brittle fragmentation. The global volume of ice and its distribution between the ocean basins present a very strong interannual variability only partially explained by the number of large icebergs. Indeed, vast zones of the Southern Ocean free of large icebergs are largely populated by small iceberg drifting over thousands of kilometers. The correlation between the global small and large icebergs volumes shows that small icebergs are mainly generated by large ones breaking. Drifting and trapping by sea ice can transport small icebergs for long period and distances. Small icebergs act as an ice diffuse process along large icebergs trajectories while sea ice trapping acts as a buffer delaying melting.

Long-term (17 Ma) turbidite record of the timing and frequency of large flank collapses of the Canary Islands

NASA Astrophysics Data System (ADS)

Hunt, J. E.; Talling, P. J.; Clare, M. A.; Jarvis, I.; Wynn, R. B.

2014-08-01

Volcaniclastic turbidites on the Madeira Abyssal Plain provide a record of large-volume volcanic island flank collapses from the Canary Islands. This long-term record spans 17 Ma, and comprises 125 volcaniclastic beds. Determining the timing, provenance and volumes of these turbidites provides key information about the occurrence of mass wasting from the Canary Islands, especially the western islands of Tenerife, La Palma and El Hierro. These turbidite records demonstrate that landslides often coincide with protracted periods of volcanic edifice growth, suggesting that loading of the volcanic edifices may be a key preconditioning factor for landslide triggers. Furthermore, the last large-volume failures from Tenerife coincide with explosive volcanism at the end of eruptive cycles. Many large-volume Canary Island landslides also occurred during periods of warmer and wetter climates associated with sea-level rise and subsequent highstand. However, these turbidites are not serially dependent and any association with climate or sea level change is not statistically significant.

System for creating on site, remote from a sterile environment, parenteral solutions

NASA Technical Reports Server (NTRS)

Finley, Mike (Inventor); Scharf, Mike (Inventor); Packard, Jeff (Inventor); Kipp, Jim (Inventor); Dudar, Tom (Inventor); Owens, Jim (Inventor); Bindokas, Al (Inventor)

1996-01-01

The present invention provides a system and method for creating on site, remote from a sterile environment, parenteral solutions in large volume parenteral containers for intravenous administration to a patient. In an embodiment, this system comprises an empty large volume container including at least one port for accessing an interior of the container. The port includes a sterilizing filter for sterilizing a fluid fed through the port into the container. A second container is provided including a solute and having means for coupling the second container to the large volume container and thereby providing fluid communication therebetween allowing the solute to be received within the interior of the container. A sterile water source is also provided including means for placing the sterile water source in fluid communication with the port and allowing water to flow from the sterile water source into the interior of the container. This allows the solute, and sterile water that has been fed through the filter, to create a parenteral solution in the large volume parenteral container.

Volume server: A scalable high speed and high capacity magnetic tape archive architecture with concurrent multi-host access

NASA Technical Reports Server (NTRS)

Rybczynski, Fred

1993-01-01

A major challenge facing data processing centers today is data management. This includes the storage of large volumes of data and access to it. Current media storage for large data volumes is typically off line and frequently off site in warehouses. Access to data archived in this fashion can be subject to long delays, errors in media selection and retrieval, and even loss of data through misplacement or damage to the media. Similarly, designers responsible for architecting systems capable of continuous high-speed recording of large volumes of digital data are faced with the challenge of identifying technologies and configurations that meet their requirements. Past approaches have tended to evaluate the combination of the fastest tape recorders with the highest capacity tape media and then to compromise technology selection as a consequence of cost. This paper discusses an architecture that addresses both of these challenges and proposes a cost effective solution based on robots, high speed helical scan tape drives, and large-capacity media.

Large woody debris in a second-growth central Appalachian hardwood stand: volume, composition, and dynamics

Treesearch

M. B. Adams; T. M. Schuler; W. M. Ford; J. N. Kochenderfer

2003-01-01

We estimated the volume of large woody debris in a second-growth stand and evaluated the importance of periodic windstorms as disturbances in creating large woody debris. This research was conducted on a reference watershed (Watershed 4) on the Fernow Experimental Forest in West Virginia. The 38-ha stand on Watershed 4 was clearcut around 1911 and has been undisturbed...

Large-Scale Operations Management Test of Use of the White Amur for Control of Problem Aquatic Plants. Report 2. First Year Poststocking Results. Volume III. The Plankton and Benthos of Lake Conway, Florida,

DTIC Science & Technology

1981-11-01

AD-AI09 516 FLORIDA UNIV GAINESVILLE DEPT OF ENVIRONMENTAL ENGIN--ETC F/G 6/6 LARGE-SCALE OPERATIONS MANAGEMENT TEST OF USE OF THE,WHITE AMUR--ETC(U... OPERATIONS MANAGEMENT TEST OF USE OF THE WHITE AMUR FOR CONTROL OF PROBLEM AQUATIC PLANTS Report I: Baseline Studies Volume I: The Aquatic Macropyes of...COVERED LARGE-SCALE OPERATIONS MANAGEMENT TEST OF USE OF Report 2 of a series THE WHITE AMUR FOR CONTROL OF PROBLEM AQUATIC (In 7 volumes) PLANTS

Low energy prompt gamma-ray tests of a large volume BGO detector.

PubMed

Naqvi, A A; Kalakada, Zameer; Al-Anezi, M S; Raashid, M; Khateeb-ur-Rehman; Maslehuddin, M; Garwan, M A

2012-01-01

Tests of a large volume Bismuth Germinate (BGO) detector were carried out to detect low energy prompt gamma-rays from boron and cadmium-contaminated water samples using a portable neutron generator-based Prompt Gamma Neutron Activation Analysis (PGNAA) setup. Inspite of strong interference between the sample- and the detector-associated prompt gamma-rays, an excellent agreement has been observed between the experimental and calculated yields of the prompt gamma-rays, indicating successful application of the large volume BGO detector in the PGNAA analysis of bulk samples using low energy prompt gamma-rays. Copyright © 2011 Elsevier Ltd. All rights reserved.

Production of large resonant plasma volumes in microwave electron cyclotron resonance ion sources

DOEpatents

Alton, Gerald D.

1998-01-01

Microwave injection methods for enhancing the performance of existing electron cyclotron resonance (ECR) ion sources. The methods are based on the use of high-power diverse frequency microwaves, including variable-frequency, multiple-discrete-frequency, and broadband microwaves. The methods effect large resonant "volume" ECR regions in the ion sources. The creation of these large ECR plasma volumes permits coupling of more microwave power into the plasma, resulting in the heating of a much larger electron population to higher energies, the effect of which is to produce higher charge state distributions and much higher intensities within a particular charge state than possible in present ECR ion sources.

A multiresolution approach to iterative reconstruction algorithms in X-ray computed tomography.

PubMed

De Witte, Yoni; Vlassenbroeck, Jelle; Van Hoorebeke, Luc

2010-09-01

In computed tomography, the application of iterative reconstruction methods in practical situations is impeded by their high computational demands. Especially in high resolution X-ray computed tomography, where reconstruction volumes contain a high number of volume elements (several giga voxels), this computational burden prevents their actual breakthrough. Besides the large amount of calculations, iterative algorithms require the entire volume to be kept in memory during reconstruction, which quickly becomes cumbersome for large data sets. To overcome this obstacle, we present a novel multiresolution reconstruction, which greatly reduces the required amount of memory without significantly affecting the reconstructed image quality. It is shown that, combined with an efficient implementation on a graphical processing unit, the multiresolution approach enables the application of iterative algorithms in the reconstruction of large volumes at an acceptable speed using only limited resources.

Forced transport of thermal energy in magmatic and phreatomagmatic large volume ignimbrites: Paleomagnetic evidence from the Colli Albani volcano, Italy

NASA Astrophysics Data System (ADS)

Trolese, Matteo; Giordano, Guido; Cifelli, Francesca; Winkler, Aldo; Mattei, Massimo

2017-11-01

Few studies have detailed the thermal architecture of large-volume pyroclastic density current deposits, although such work has a clear importance for understanding the dynamics of eruptions of this magnitude. Here we examine the temperature of emplacement of large-volume caldera-forming ignimbrites related to magmatic and phreatomagmatic eruptions at the Colli Albani volcano, Italy, by using thermal remanent magnetization analysis on both lithic and juvenile clasts. Results show that all the magmatic ignimbrites were deposited at high temperature, between the maximum blocking temperature of the magnetic carrier (600-630 °C) and the glass transition temperature (about 710 °C). Temperature estimations for the phreatomagmatic ignimbrite range between 200 and 400 °C, with most of the clasts emplaced between 200 and 320 °C. Because all the investigated ignimbrites, magmatic and phreatomagmatic, share similar magma composition, volume and mobility, we attribute the temperature difference to magma-water interaction, highlighting its pronounced impact on thermal dissipation, even in large-volume eruptions. The homogeneity of the deposit temperature of each ignimbrite across its areal extent, which is maintained across topographic barriers, suggests that these systems are thermodynamically isolated from the external environment for several tens of kilometers. Based on these findings, we propose that these large-volume ignimbrites are dominated by the mass flux, which forces the lateral transport of mass, momentum, and thermal energy for distances up to tens of kilometers away from the vent. We conclude that spatial variation of the emplacement temperature can be used as a proxy for determining the degree of forced-convection flow.

Large increase in nest size linked to climate change: an indicator of life history, senescence and condition.

PubMed

Møller, Anders Pape; Nielsen, Jan Tøttrup

2015-11-01

Many animals build extravagant nests that exceed the size required for successful reproduction. Large nests may signal the parenting ability of nest builders suggesting that nests may have a signaling function. In particular, many raptors build very large nests for their body size. We studied nest size in the goshawk Accipiter gentilis, which is a top predator throughout most of the Nearctic. Both males and females build nests, and males provision their females and offspring with food. Nest volume in the goshawk is almost three-fold larger than predicted from their body size. Nest size in the goshawk is highly variable and may reach more than 600 kg for a bird that weighs ca. 1 kg. While 8.5% of nests fell down, smaller nests fell down more often than large nests. There was a hump-shaped relationship between nest volume and female age, with a decline in nest volume late in life, as expected for senescence. Clutch size increased with nest volume. Nest volume increased during 1977-2014 in an accelerating fashion, linked to increasing spring temperature during April, when goshawks build and start reproduction. These findings are consistent with nest size being a reliable signal of parental ability, with large nest size signaling superior parenting ability and senescence, and also indicating climate warming.

The clockwork supergravity

NASA Astrophysics Data System (ADS)

Kehagias, Alex; Riotto, Antonio

2018-02-01

We show that the minimal D = 5, N = 2 gauged supergravity set-up may encode naturally the recently proposed clockwork mechanism. The minimal embedding requires one vector multiplet in addition to the supergravity multiplet and the clockwork scalar is identified with the scalar in the vector multiplet. The scalar has a two-parameter potential and it can accommodate the clockwork, the Randall-Sundrum and a no-scale model with a flat potential, depending on the values of the parameters. The continuous clockwork background breaks half of the original supersymmetries, leaving a D = 4, N = 1 theory on the boundaries. We also show that the generated hierarchy by the clockwork is not exponential but rather power law. The reason is that four-dimensional Planck scale has a power-law dependence on the compactification radius, whereas the corresponding KK spectrum depends on the logarithm of the latter.

Axions, inflation and the anthropic principle

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mack, Katherine J., E-mail: mack@ast.cam.ac.uk

2011-07-01

The QCD axion is the leading solution to the strong-CP problem, a dark matter candidate, and a possible result of string theory compactifications. However, for axions produced before inflation, symmetry-breaking scales of f{sub a}∼>10{sup 12} GeV (which are favored in string-theoretic axion models) are ruled out by cosmological constraints unless both the axion misalignment angle θ{sub 0} and the inflationary Hubble scale H{sub I} are extremely fine-tuned. We show that attempting to accommodate a high-f{sub a} axion in inflationary cosmology leads to a fine-tuning problem that is worse than the strong-CP problem the axion was originally invented to solve. Wemore » also show that this problem remains unresolved by anthropic selection arguments commonly applied to the high-f{sub a} axion scenario.« less

Inflation from periodic extra dimensions

NASA Astrophysics Data System (ADS)

Higaki, Tetsutaro; Tatsuta, Yoshiyuki

2017-07-01

We discuss a realization of a small field inflation based on string inspired supergravities. In theories accompanying extra dimensions, compactification of them with small radii is required for realistic situations. Since the extra dimension can have a periodicity, there will appear (quasi-)periodic functions under transformations of moduli of the extra dimensions in low energy scales. Such a periodic property can lead to a UV completion of so-called multi-natural inflation model where inflaton potential consists of a sum of multiple sinusoidal functions with a decay constant smaller than the Planck scale. As an illustration, we construct a SUSY breaking model, and then show that such an inflaton potential can be generated by a sum of world sheet instantons in intersecting brane models on extra dimensions containing orbifold. We show also predictions of cosmic observables by numerical analyzes.

The Hodge-Elliptic Genus, Spinning BPS States, and Black Holes

NASA Astrophysics Data System (ADS)

Kachru, Shamit; Tripathy, Arnav

2017-10-01

We perform a refined count of BPS states in the compactification of M-theory on {K3 × T^2}, keeping track of the information provided by both the {SU(2)_L} and {SU(2)_R} angular momenta in the SO(4) little group. Mathematically, this four variable counting function may be expressed via the motivic Donaldson-Thomas counts of {K3 × T^2}, simultaneously refining Katz, Klemm, and Pandharipande's motivic stable pairs counts on K3 and Oberdieck-Pandharipande's Gromov-Witten counts on {K3 × T^2}. This provides the first full answer for motivic curve counts of a compact Calabi-Yau threefold. Along the way, we develop a Hodge-elliptic genus for Calabi-Yau manifolds—a new counting function for BPS states that interpolates between the Hodge polynomial and the elliptic genus of a Calabi-Yau.

Inflation from periodic extra dimensions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Higaki, Tetsutaro; Tatsuta, Yoshiyuki, E-mail: thigaki@rk.phys.keio.ac.jp, E-mail: y_tatsuta@akane.waseda.jp

We discuss a realization of a small field inflation based on string inspired supergravities. In theories accompanying extra dimensions, compactification of them with small radii is required for realistic situations. Since the extra dimension can have a periodicity, there will appear (quasi-)periodic functions under transformations of moduli of the extra dimensions in low energy scales. Such a periodic property can lead to a UV completion of so-called multi-natural inflation model where inflaton potential consists of a sum of multiple sinusoidal functions with a decay constant smaller than the Planck scale. As an illustration, we construct a SUSY breaking model, andmore » then show that such an inflaton potential can be generated by a sum of world sheet instantons in intersecting brane models on extra dimensions containing orbifold. We show also predictions of cosmic observables by numerical analyzes.« less

On a fourth order accurate implicit finite difference scheme for hyperbolic conservation laws. II - Five-point schemes

NASA Technical Reports Server (NTRS)

Harten, A.; Tal-Ezer, H.

1981-01-01

This paper presents a family of two-level five-point implicit schemes for the solution of one-dimensional systems of hyperbolic conservation laws, which generalized the Crank-Nicholson scheme to fourth order accuracy (4-4) in both time and space. These 4-4 schemes are nondissipative and unconditionally stable. Special attention is given to the system of linear equations associated with these 4-4 implicit schemes. The regularity of this system is analyzed and efficiency of solution-algorithms is examined. A two-datum representation of these 4-4 implicit schemes brings about a compactification of the stencil to three mesh points at each time-level. This compact two-datum representation is particularly useful in deriving boundary treatments. Numerical results are presented to illustrate some properties of the proposed scheme.

Fivebranes and 3-manifold homology

NASA Astrophysics Data System (ADS)

Gukov, Sergei; Putrov, Pavel; Vafa, Cumrun

2017-07-01

Motivated by physical constructions of homological knot invariants, we study their analogs for closed 3-manifolds. We show that fivebrane compactifications provide a universal description of various old and new homological invariants of 3-manifolds. In terms of 3d/3d correspondence, such invariants are given by the Q-cohomology of the Hilbert space of partially topologically twisted 3d N=2 theory T[ M 3] on a Riemann surface with defects. We demonstrate this by concrete and explicit calculations in the case of monopole/Heegaard Floer homology and a 3-manifold analog of Khovanov-Rozansky link homology. The latter gives a categorification of Chern-Simons partition function. Some of the new key elements include the explicit form of the S-transform and a novel connection between categorification and a previously mysterious role of Eichler integrals in Chern-Simons theory.

T-duality of singular spacetime compactifications in an H-flux

NASA Astrophysics Data System (ADS)

Linshaw, Andrew; Mathai, Varghese

2018-07-01

We begin by presenting a symmetric version of the circle equivariant T-duality result in a joint work of the second author with Siye Wu, thereby generalizing the results there. We then initiate the study of twisted equivariant Courant algebroids and equivariant generalized geometry and apply it to our context. As before, T-duality exchanges type IIA and type IIB string theories. In our theory, both spacetime and the T-dual spacetime can be singular spaces when the fixed point set is non-empty; the singularities correspond to Kaluza-Klein monopoles. We propose that the Ramond-Ramond charges of type II string theories on the singular spaces are classified by twisted equivariant cohomology groups, consistent with the previous work of Mathai and Wu, and prove that they are naturally isomorphic. We also establish the corresponding isomorphism of twisted equivariant Courant algebroids.

Cosmic acceleration from M theory on twisted spaces

DOE Office of Scientific and Technical Information (OSTI.GOV)

Neupane, Ishwaree P.; Wiltshire, David L.

2005-10-15

In a recent paper [I. P. Neupane and D. L. Wiltshire, Phys. Lett. B 619, 201 (2005).] we have found a new class of accelerating cosmologies arising from a time-dependent compactification of classical supergravity on product spaces that include one or more geometric twists along with nontrivial curved internal spaces. With such effects, a scalar potential can have a local minimum with positive vacuum energy. The existence of such a minimum generically predicts a period of accelerated expansion in the four-dimensional Einstein conformal frame. Here we extend our knowledge of these cosmological solutions by presenting new examples and discuss themore » properties of the solutions in a more general setting. We also relate the known (asymptotic) solutions for multiscalar fields with exponential potentials to the accelerating solutions arising from simple (or twisted) product spaces for internal manifolds.« less

Cosmic infinity: a dynamical system approach

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bouhmadi-López, Mariam; Marto, João; Morais, João

2017-03-01

Dynamical system techniques are extremely useful to study cosmology. It turns out that in most of the cases, we deal with finite isolated fixed points corresponding to a given cosmological epoch. However, it is equally important to analyse the asymptotic behaviour of the universe. On this paper, we show how this can be carried out for 3-form models. In fact, we show that there are fixed points at infinity mainly by introducing appropriate compactifications and defining a new time variable that washes away any potential divergence of the system. The richness of 3-form models allows us as well to identifymore » normally hyperbolic non-isolated fixed points. We apply this analysis to three physically interesting situations: (i) a pre-inflationary era; (ii) an inflationary era; (iii) the late-time dark matter/dark energy epoch.« less

A New Electropositive Filter for Concentrating Enterovirus and Norovirus from Large Volumes of Water - MCEARD

EPA Science Inventory

The detection of enteric viruses in environmental water usually requires the concentration of viruses from large volumes of water. The 1MDS electropositive filter is commonly used for concentrating enteric viruses from water but unfortunately these filters are not cost-effective...

ANALYSIS OF LOW-LEVEL PESTICIDES FROM HIGH-ELEVATION LAKE WATERS BY LARGE VOLUME INJECTION GCMS

EPA Science Inventory

This paper describes the method development for the determination of ultra-low level pesticides from high-elevation lake waters by large-volume injection programmable temperature vaporizer (LVI-PTV) GC/MS. This analytical method is developed as a subtask of a larger study, backgr...

Development of a Solid Phase Extraction Method for Agricultural Pesticides in Large-Volume Water Samples

EPA Science Inventory

An analytical method using solid phase extraction (SPE) and analysis by gas chromatography/mass spectrometry (GC/MS) was developed for the trace determination of a variety of agricultural pesticides and selected transformation products in large-volume high-elevation lake water sa...

The multidimensional behavioural hypervolumes of two interacting species predict their space use and survival

PubMed Central

Lichtenstein, James L. L.; Wright, Colin M; McEwen, Brendan; Pinter-Wollman, Noa; Pruitt, Jonathan N.

2018-01-01

Individual animals differ consistently in their behaviour, thus impacting a wide variety of ecological outcomes. Recent advances in animal personality research have established the ecological importance of the multidimensional behavioural volume occupied by individuals and by multispecies communities. Here, we examine the degree to which the multidimensional behavioural volume of a group predicts the outcome of both intra- and interspecific interactions. In particular, we test the hypothesis that a population of conspecifics will experience low intraspecific competition when the population occupies a large volume in behavioural space. We further hypothesize that populations of interacting species will exhibit greater interspecific competition when one or both species occupy large volumes in behavioural space. We evaluate these hypotheses by studying groups of katydids (Scudderia nymphs) and froghoppers (Philaenus spumarius), which compete for food and space on their shared host plant, Solidago canadensis. We found that individuals in single-species groups of katydids positioned themselves closer to one another, suggesting reduced competition, when groups occupied a large behavioural volume. When both species were placed together, we found that the survival of froghoppers was greatest when both froghoppers and katydids occupied a small volume in behavioural space, particularly at high froghopper densities. These results suggest that groups that occupy large behavioural volumes can have low intraspecific competition but high interspecific competition. Thus, behavioural hypervolumes appear to have ecological consequences at both the level of the population and the community and may help to predict the intensity of competition both within and across species. PMID:29681647

Melt Electrospinning Writing of Highly Ordered Large Volume Scaffold Architectures.

PubMed

Wunner, Felix M; Wille, Marie-Luise; Noonan, Thomas G; Bas, Onur; Dalton, Paul D; De-Juan-Pardo, Elena M; Hutmacher, Dietmar W

2018-05-01

The additive manufacturing of highly ordered, micrometer-scale scaffolds is at the forefront of tissue engineering and regenerative medicine research. The fabrication of scaffolds for the regeneration of larger tissue volumes, in particular, remains a major challenge. A technology at the convergence of additive manufacturing and electrospinning-melt electrospinning writing (MEW)-is also limited in thickness/volume due to the accumulation of excess charge from the deposited material repelling and hence, distorting scaffold architectures. The underlying physical principles are studied that constrain MEW of thick, large volume scaffolds. Through computational modeling, numerical values variable working distances are established respectively, which maintain the electrostatic force at a constant level during the printing process. Based on the computational simulations, three voltage profiles are applied to determine the maximum height (exceeding 7 mm) of a highly ordered large volume scaffold. These thick MEW scaffolds have fully interconnected pores and allow cells to migrate and proliferate. To the best of the authors knowledge, this is the first study to report that z-axis adjustment and increasing the voltage during the MEW process allows for the fabrication of high-volume scaffolds with uniform morphologies and fiber diameters. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Volcanic stratigraphy of large-volume silicic pyroclastic eruptions during Oligocene Afro-Arabian flood volcanism in Yemen

NASA Astrophysics Data System (ADS)

Peate, Ingrid Ukstins; Baker, Joel A.; Al-Kadasi, Mohamed; Al-Subbary, Abdulkarim; Knight, Kim B.; Riisager, Peter; Thirlwall, Matthew F.; Peate, David W.; Renne, Paul R.; Menzies, Martin A.

2005-12-01

A new stratigraphy for bimodal Oligocene flood volcanism that forms the volcanic plateau of northern Yemen is presented based on detailed field observations, petrography and geochemical correlations. The >1 km thick volcanic pile is divided into three phases of volcanism: a main basaltic stage (31 to 29.7 Ma), a main silicic stage (29.7 to 29.5 Ma), and a stage of upper bimodal volcanism (29.5 to 27.7 Ma). Eight large-volume silicic pyroclastic eruptive units are traceable throughout northern Yemen, and some units can be correlated with silicic eruptive units in the Ethiopian Traps and to tephra layers in the Indian Ocean. The silicic units comprise pyroclastic density current and fall deposits and a caldera-collapse breccia, and they display textures that unequivocally identify them as primary pyroclastic deposits: basal vitrophyres, eutaxitic fabrics, glass shards, vitroclastic ash matrices and accretionary lapilli. Individual pyroclastic eruptions have preserved on-land volumes of up to ˜850 km3. The largest units have associated co-ignimbrite plume ash fall deposits with dispersal areas >1×107 km2 and estimated maximum total volumes of up to 5,000 km3, which provide accurate and precisely dated marker horizons that can be used to link litho-, bio- and magnetostratigraphy studies. There is a marked change in eruption style of silicic units with time, from initial large-volume explosive pyroclastic eruptions producing ignimbrites and near-globally distributed tuffs, to smaller volume (<50 km3) mixed effusive-explosive eruptions emplacing silicic lavas intercalated with tuffs and ignimbrites. Although eruption volumes decrease by an order of magnitude from the first stage to the last, eruption intervals within each phase remain broadly similar. These changes may reflect the initiation of continental rifting and the transition from pre-break-up thick, stable crust supporting large-volume magma chambers, to syn-rift actively thinning crust hosting small-volume magma chambers.

Measures for a multidimensional multiverse

NASA Astrophysics Data System (ADS)

Chung, Hyeyoun

2015-04-01

We explore the phenomenological implications of generalizing the causal patch and fat geodesic measures to a multidimensional multiverse, where the vacua can have differing numbers of large dimensions. We consider a simple model in which the vacua are nucleated from a D -dimensional parent spacetime through dynamical compactification of the extra dimensions, and compute the geometric contribution to the probability distribution of observations within the multiverse for each measure. We then study how the shape of this probability distribution depends on the time scales for the existence of observers, for vacuum domination, and for curvature domination (tobs,tΛ , and tc, respectively.) In this work we restrict ourselves to bubbles with positive cosmological constant, Λ . We find that in the case of the causal patch cutoff, when the bubble universes have p +1 large spatial dimensions with p ≥2 , the shape of the probability distribution is such that we obtain the coincidence of time scales tobs˜tΛ˜tc . Moreover, the size of the cosmological constant is related to the size of the landscape. However, the exact shape of the probability distribution is different in the case p =2 , compared to p ≥3 . In the case of the fat geodesic measure, the result is even more robust: the shape of the probability distribution is the same for all p ≥2 , and we once again obtain the coincidence tobs˜tΛ˜tc . These results require only very mild conditions on the prior probability of the distribution of vacua in the landscape. Our work shows that the observed double coincidence of time scales is a robust prediction even when the multiverse is generalized to be multidimensional; that this coincidence is not a consequence of our particular Universe being (3 +1 )-dimensional; and that this observable cannot be used to preferentially select one measure over another in a multidimensional multiverse.

Fracking, fracture, and permeability

NASA Astrophysics Data System (ADS)

Turcotte, D. L.; Norris, J.; Rundle, J. B.

2013-12-01

Injections of large volumes of water into tight shale reservoirs allows the extraction of oil and gas not previously accessible. This large volume 'super' fracking induces damage that allows the oil and/or gas to flow to an extraction well. The purpose of this paper is to provide a model for understanding super fracking. We assume that water is injected from a small spherical cavity into a homogeneous elastic medium. The high pressure of the injected water generates hoop stresses that reactivate natural fractures in the tight shales. These fractures migrate outward as water is added creating a spherical shell of damaged rock. The porosity associated with these fractures is equal to the water volume injected. We obtain an analytic expression for this volume. We apply our model to a typical tight shale reservoir and show that the predicted water volumes are in good agreement with the volumes used in super fracking.

Partial molar volume of n-alcohols at infinite dilution in water calculated by means of scaled particle theory.

PubMed

Graziano, Giuseppe

2006-04-07

The partial molar volume of n-alcohols at infinite dilution in water is smaller than the molar volume in the neat liquid phase. It is shown that the formula for the partial molar volume at infinite dilution obtained from the scaled particle theory equation of state for binary hard sphere mixtures is able to reproduce in a satisfactory manner the experimental data over a large temperature range. This finding implies that the packing effects play the fundamental role in determining the partial molar volume at infinite dilution in water also for solutes, such as n-alcohols, forming H bonds with water molecules. Since the packing effects in water are largely related to the small size of its molecules, the latter feature is the ultimate cause of the decrease in partial molar volume associated with the hydrophobic effect.

Evaluation of a laser scanner for large volume coordinate metrology: a comparison of results before and after factory calibration

NASA Astrophysics Data System (ADS)

Ferrucci, M.; Muralikrishnan, B.; Sawyer, D.; Phillips, S.; Petrov, P.; Yakovlev, Y.; Astrelin, A.; Milligan, S.; Palmateer, J.

2014-10-01

Large volume laser scanners are increasingly being used for a variety of dimensional metrology applications. Methods to evaluate the performance of these scanners are still under development and there are currently no documentary standards available. This paper describes the results of extensive ranging and volumetric performance tests conducted on a large volume laser scanner. The results demonstrated small but clear systematic errors that are explained in the context of a geometric error model for the instrument. The instrument was subsequently returned to the manufacturer for factory calibration. The ranging and volumetric tests were performed again and the results are compared against those obtained prior to the factory calibration.

Production of large resonant plasma volumes in microwave electron cyclotron resonance ion sources

DOEpatents

Alton, G.D.

1998-11-24

Microwave injection methods are disclosed for enhancing the performance of existing electron cyclotron resonance (ECR) ion sources. The methods are based on the use of high-power diverse frequency microwaves, including variable-frequency, multiple-discrete-frequency, and broadband microwaves. The methods effect large resonant ``volume`` ECR regions in the ion sources. The creation of these large ECR plasma volumes permits coupling of more microwave power into the plasma, resulting in the heating of a much larger electron population to higher energies, the effect of which is to produce higher charge state distributions and much higher intensities within a particular charge state than possible in present ECR ion sources. 5 figs.

Large discharge-volume, silent discharge spark plug

DOEpatents

Kang, Michael

1995-01-01

A large discharge-volume spark plug for providing self-limiting microdischarges. The apparatus includes a generally spark plug-shaped arrangement of a pair of electrodes, where either of the two coaxial electrodes is substantially shielded by a dielectric barrier from a direct discharge from the other electrode, the unshielded electrode and the dielectric barrier forming an annular volume in which self-terminating microdischarges occur when alternating high voltage is applied to the center electrode. The large area over which the discharges occur, and the large number of possible discharges within the period of an engine cycle, make the present silent discharge plasma spark plug suitable for use as an ignition source for engines. In the situation, where a single discharge is effective in causing ignition of the combustible gases, a conventional single-polarity, single-pulse, spark plug voltage supply may be used.

Measuring and mitigating inhibition during real-time, quantitative PCR analysis of viral nucleic acid extracts from large-volume environmental water samples

USDA-ARS?s Scientific Manuscript database

Naturally-occurring inhibitory compounds are a major concern during qPCR and RT-qPCR analysis of environmental samples, particularly large volume water samples. Here, a standardized method for measuring and mitigating sample inhibition in environmental water concentrates is described. Specifically, ...

Improving IT Portfolio Management Decision Confidence Using Multi-Criteria Decision Making and Hypervariate Display Techniques

ERIC Educational Resources Information Center

Landmesser, John Andrew

2014-01-01

Information technology (IT) investment decision makers are required to process large volumes of complex data. An existing body of knowledge relevant to IT portfolio management (PfM), decision analysis, visual comprehension of large volumes of information, and IT investment decision making suggest Multi-Criteria Decision Making (MCDM) and…

Effect of filtration rates on hollow fiber ultrafilter concentration of viruses and protozoans from large volumes of water

EPA Science Inventory

Aims: To describe the ability of tangential flow hollow-fiber ultrafiltration to recover viruses from large volumes of water when run either at high filtration rates or lower filtration rates and recover Cryptosporidium parvum at high filtration rates. Methods and Results: Wate...

A unified econophysics explanation for the power-law exponents of stock market activity

NASA Astrophysics Data System (ADS)

Gabaix, Xavier; Gopikrishnan, Parameswaran; Plerou, Vasiliki; Stanley, Eugene

2007-08-01

We survey a theory (first sketched in Nature in 2003, then fleshed out in the Quarterly Journal of Economics in 2006) of the economic underpinnings of the fat-tailed distributions of a number of financial variables, such as returns and trading volume. Our theory posits that they have a common origin in the strategic trading behavior of very large financial institutions in a relatively illiquid market. We show how the fat-tailed distribution of fund sizes can indeed generate extreme returns and volumes, even in the absence of fundamental news. Moreover, we are able to replicate the individually different empirical values of the power-law exponents for each distribution: 3 for returns, 3/2 for volumes, 1 for the assets under management of large investors. Large investors moderate their trades to reduce their price impact; coupled with a concave price impact function, this leads to volumes being more fat-tailed than returns but less fat-tailed than fund sizes. The trades of large institutions also offer a unified explanation for apparently disconnected empirical regularities that are otherwise a challenge for economic theory.

Twitter-Based Analysis of the Dynamics of Collective Attention to Political Parties

PubMed Central

Eom, Young-Ho; Puliga, Michelangelo; Smailović, Jasmina; Mozetič, Igor; Caldarelli, Guido

2015-01-01

Large-scale data from social media have a significant potential to describe complex phenomena in the real world and to anticipate collective behaviors such as information spreading and social trends. One specific case of study is represented by the collective attention to the action of political parties. Not surprisingly, researchers and stakeholders tried to correlate parties' presence on social media with their performances in elections. Despite the many efforts, results are still inconclusive since this kind of data is often very noisy and significant signals could be covered by (largely unknown) statistical fluctuations. In this paper we consider the number of tweets (tweet volume) of a party as a proxy of collective attention to the party, identify the dynamics of the volume, and show that this quantity has some information on the election outcome. We find that the distribution of the tweet volume for each party follows a log-normal distribution with a positive autocorrelation of the volume over short terms, which indicates the volume has large fluctuations of the log-normal distribution yet with a short-term tendency. Furthermore, by measuring the ratio of two consecutive daily tweet volumes, we find that the evolution of the daily volume of a party can be described by means of a geometric Brownian motion (i.e., the logarithm of the volume moves randomly with a trend). Finally, we determine the optimal period of averaging tweet volume for reducing fluctuations and extracting short-term tendencies. We conclude that the tweet volume is a good indicator of parties' success in the elections when considered over an optimal time window. Our study identifies the statistical nature of collective attention to political issues and sheds light on how to model the dynamics of collective attention in social media. PMID:26161795

Twitter-Based Analysis of the Dynamics of Collective Attention to Political Parties.

PubMed

Eom, Young-Ho; Puliga, Michelangelo; Smailović, Jasmina; Mozetič, Igor; Caldarelli, Guido

2015-01-01

Large-scale data from social media have a significant potential to describe complex phenomena in the real world and to anticipate collective behaviors such as information spreading and social trends. One specific case of study is represented by the collective attention to the action of political parties. Not surprisingly, researchers and stakeholders tried to correlate parties' presence on social media with their performances in elections. Despite the many efforts, results are still inconclusive since this kind of data is often very noisy and significant signals could be covered by (largely unknown) statistical fluctuations. In this paper we consider the number of tweets (tweet volume) of a party as a proxy of collective attention to the party, identify the dynamics of the volume, and show that this quantity has some information on the election outcome. We find that the distribution of the tweet volume for each party follows a log-normal distribution with a positive autocorrelation of the volume over short terms, which indicates the volume has large fluctuations of the log-normal distribution yet with a short-term tendency. Furthermore, by measuring the ratio of two consecutive daily tweet volumes, we find that the evolution of the daily volume of a party can be described by means of a geometric Brownian motion (i.e., the logarithm of the volume moves randomly with a trend). Finally, we determine the optimal period of averaging tweet volume for reducing fluctuations and extracting short-term tendencies. We conclude that the tweet volume is a good indicator of parties' success in the elections when considered over an optimal time window. Our study identifies the statistical nature of collective attention to political issues and sheds light on how to model the dynamics of collective attention in social media.

Stage-dependent remodeling of the nuclear envelope and lamina during rabbit early embryonic development.

PubMed

Popken, Jens; Schmid, Volker J; Strauss, Axel; Guengoer, Tuna; Wolf, Eckhard; Zakhartchenko, Valeri

2016-04-22

Utilizing 3D structured illumination microscopy, we investigated the quality and quantity of nuclear invaginations and the distribution of nuclear pores during rabbit early embryonic development and identified the exact time point of nucleoporin 153 (NUP153) association with chromatin during mitosis. Contrary to bovine early embryonic nuclei, featuring almost exclusively nuclear invaginations containing a small volume of cytoplasm, nuclei in rabbit early embryonic stages show additionally numerous invaginations containing a large volume of cytoplasm. Small-volume invaginations frequently emanated from large-volume nuclear invaginations but not vice versa, indicating a different underlying mechanism. Large- and small-volume nuclear envelope invaginations required the presence of chromatin, as they were restricted to chromatin-positive areas. The chromatin-free contact areas between nucleolar precursor bodies (NPBs) and large-volume invaginations were free of nuclear pores. Small-volume invaginations were not in contact with NPBs. The number of invaginations and isolated intranuclear vesicles per nucleus peaked at the 4-cell stage. At this stage, the nuclear surface showed highly concentrated clusters of nuclear pores surrounded by areas free of nuclear pores. Isolated intranuclear lamina vesicles were usually NUP153 negative. Cytoplasmic, randomly distributed NUP153-positive clusters were highly abundant at the zygote stage and decreased in number until they were almost absent at the 8-cell stage and later. These large NUP153 clusters may represent a maternally provided NUP153 deposit, but they were not visible as clusters during mitosis. Major genome activation at the 8- to 16-cell stage may mark the switch from a necessity for a deposit to on-demand production. NUP153 association with chromatin is initiated during metaphase before the initiation of the regeneration of the lamina. To our knowledge, the present study demonstrates for the first time major remodeling of the nuclear envelope and its underlying lamina during rabbit preimplantation development.

An automated landmark-based elastic registration technique for large deformation recovery from 4-D CT lung images

NASA Astrophysics Data System (ADS)

Negahdar, Mohammadreza; Zacarias, Albert; Milam, Rebecca A.; Dunlap, Neal; Woo, Shiao Y.; Amini, Amir A.

2012-03-01

The treatment plan evaluation for lung cancer patients involves pre-treatment and post-treatment volume CT imaging of the lung. However, treatment of the tumor volume lung results in structural changes to the lung during the course of treatment. In order to register the pre-treatment volume to post-treatment volume, there is a need to find robust and homologous features which are not affected by the radiation treatment along with a smooth deformation field. Since airways are well-distributed in the entire lung, in this paper, we propose use of airway tree bifurcations for registration of the pre-treatment volume to the post-treatment volume. A dedicated and automated algorithm has been developed that finds corresponding airway bifurcations in both images. To derive the 3-D deformation field, a B-spline transformation model guided by mutual information similarity metric was used to guarantee the smoothness of the transformation while combining global information from bifurcation points. Therefore, the approach combines both global statistical intensity information with local image feature information. Since during normal breathing, the lung undergoes large nonlinear deformations, it is expected that the proposed method would also be applicable to large deformation registration between maximum inhale and maximum exhale images in the same subject. The method has been evaluated by registering 3-D CT volumes at maximum exhale data to all the other temporal volumes in the POPI-model data.

Stochastic theory of large-scale enzyme-reaction networks: Finite copy number corrections to rate equation models

NASA Astrophysics Data System (ADS)

Thomas, Philipp; Straube, Arthur V.; Grima, Ramon

2010-11-01

Chemical reactions inside cells occur in compartment volumes in the range of atto- to femtoliters. Physiological concentrations realized in such small volumes imply low copy numbers of interacting molecules with the consequence of considerable fluctuations in the concentrations. In contrast, rate equation models are based on the implicit assumption of infinitely large numbers of interacting molecules, or equivalently, that reactions occur in infinite volumes at constant macroscopic concentrations. In this article we compute the finite-volume corrections (or equivalently the finite copy number corrections) to the solutions of the rate equations for chemical reaction networks composed of arbitrarily large numbers of enzyme-catalyzed reactions which are confined inside a small subcellular compartment. This is achieved by applying a mesoscopic version of the quasisteady-state assumption to the exact Fokker-Planck equation associated with the Poisson representation of the chemical master equation. The procedure yields impressively simple and compact expressions for the finite-volume corrections. We prove that the predictions of the rate equations will always underestimate the actual steady-state substrate concentrations for an enzyme-reaction network confined in a small volume. In particular we show that the finite-volume corrections increase with decreasing subcellular volume, decreasing Michaelis-Menten constants, and increasing enzyme saturation. The magnitude of the corrections depends sensitively on the topology of the network. The predictions of the theory are shown to be in excellent agreement with stochastic simulations for two types of networks typically associated with protein methylation and metabolism.

What volume of seeds can a chimpanzee carry in its body?

PubMed

Nakamura, Michio; Sakamaki, Tetsuya; Zamma, Koichiro

2017-01-01

Great apes are important seed dispersers with large bodies, able to swallow large seeds and travel long distances. Although there have been several studies investigating seed dispersal quality [sensu Schupp (Vegetatio 107/108:15-29, 1993)] by chimpanzees, there is little information on the volume of seeds they can carry in their bodies. When a relatively fresh corpse of a mature female chimpanzee was found at Mahale, Tanzania, we took advantage of the rare opportunity to investigate the total weight and cubic volume of seeds recovered from the corpse. The seeds contained in the corpse weighed 258.8 g (dry weight) and measured 489.4 cm 3 . The volume of seeds was 14.7 % of the previously reported capacity of the digestive tract of a chimpanzee in captivity. We also indirectly estimated the volume of seeds from the values of observed seed volume in feces, the reported number of defecations per day, and the seed passage time. The estimated volume was significantly lower than the observed seed volume, suggesting that the number of defecations per day is underestimated because it may not include nighttime defecation.

Novel regenerative large-volume immobilized enzyme reactor: preparation, characterization and application.

PubMed

Ruan, Guihua; Wei, Meiping; Chen, Zhengyi; Su, Rihui; Du, Fuyou; Zheng, Yanjie

2014-09-15

A novel large-volume immobilized enzyme reactor (IMER) on small column was prepared with organic-inorganic hybrid silica particles and applied for fast (10 min) and oriented digestion of protein. At first, a thin enzyme support layer was formed in the bottom of the small column by polymerization with α-methacrylic acid and dimethacrylate. After that, amino SiO2 particles was prepared by the sol-gel method with tetraethoxysilane and 3-aminopropyltriethoxysilane. Subsequently, the amino SiO2 particles were activated by glutaraldehyde for covalent immobilization of trypsin. Digestive capability of large-volume IMER for proteins was investigated by using bovine serum albumin (BSA), cytochrome c (Cyt-c) as model proteins. Results showed that although the sequence coverage of the BSA (20%) and Cyt-c (19%) was low, the large-volume IMER could produce peptides with stable specific sequence at 101-105, 156-160, 205-209, 212-218, 229-232, 257-263 and 473-451 of the amino sequence of BSA when digesting 1mg/mL BSA. Eight of common peptides were observed during each of the ten runs of large-volume IMER. Besides, the IMER could be easily regenerated by reactivating with GA and cross-linking with trypsin after breaking the -C=N- bond by 0.01 M HCl. The sequence coverage of BSA from regenerated IMER increased to 25% comparing the non-regenerated IMER (17%). 14 common peptides. accounting for 87.5% of first use of IMER, were produced both with IMER and regenerated IMER. When the IMER was applied for ginkgo albumin digestion, the sequence coverage of two main proteins of ginkgo, ginnacin and legumin, was 56% and 55%, respectively. (Reviewer 2) Above all, the fast and selective digestion property of the large-volume IMER indicated that the regenerative IMER could be tentatively used for the production of potential bioactive peptides and the study of oriented protein digestion. Copyright © 2014 Elsevier B.V. All rights reserved.

Organisational and extraorganisational determinants of volume of service delivery by English community pharmacies: a cross-sectional survey and secondary data analysis

PubMed Central

Hann, Mark; Schafheutle, Ellen I; Bradley, Fay; Elvey, Rebecca; Wagner, Andrew; Halsall, Devina; Hassell, Karen

2017-01-01

Objectives This study aimed to identify the organisational and extraorganisational factors associated with existing variation in the volume of services delivered by community pharmacies. Design and setting Linear and ordered logistic regression of linked national data from secondary sources—community pharmacy activity, socioeconomic and health need datasets—and primary data from a questionnaire survey of community pharmacies in nine diverse geographical areas in England. Outcome measures Annual dispensing volume; annual volume of medicines use reviews (MURs). Results National dataset (n=10 454 pharmacies): greater dispensing volume was significantly associated with pharmacy ownership type (large chains>independents>supermarkets), greater deprivation, higher local prevalence of cardiovascular disease and depression, older people (aged >75 years) and infants (aged 0–4 years) but lower prevalence of mental health conditions. Greater volume of MURs was significantly associated with pharmacy ownership type (large chains/supermarkets>>independents), greater dispensing volume, and lower disease prevalence. Survey dataset (n=285 pharmacies; response=34.6%): greater dispensing volume was significantly associated with staffing, skill-mix, organisational culture, years open and greater deprivation. Greater MUR volume was significantly associated with pharmacy ownership type (large chains/supermarkets>>independents), greater dispensing volume, weekly opening hours and lower asthma prevalence. Conclusions Organisational and extraorganisational factors were found to impact differently on dispensing volume and MUR activity, the latter being driven more by corporate ownership than population need. While levels of staffing and skill-mix were associated with dispensing volume, they did not influence MUR activity. Despite recent changes to the contractual framework, the existing fee-for-service reimbursement may therefore not be the most appropriate for the delivery of cognitive (rather than supply) services, still appearing to incentivise quantity over the quality (in terms of appropriate targeting) of services delivered. Future research should focus on the development of quality measures that could be incorporated into community pharmacy reimbursement mechanisms. PMID:29018074

Axionic D3-D7 inflation

NASA Astrophysics Data System (ADS)

Burgess, C. P.; Cline, J. M.; Postma, M.

2009-03-01

We study the motion of a D3 brane moving within a Type IIB string vacuum compactified to 4D on K3 × T2/Z2 in the presence of D7 and O7 planes. We work within the effective 4D supergravity describing how the mobile D3 interacts with the lightest bulk moduli of the compactification, including the effects of modulus-stabilizing fluxes. We seek inflationary solutions to the resulting equations, performing our search numerically in order to avoid resorting to approximate parameterizations of the low-energy potential. We consider uplifting from D-terms and from the supersymmetry-breaking effects of anti-D3 branes. We find examples of slow-roll inflation (with anti-brane uplifting) with the mobile D3 moving along the toroidal directions, falling towards a D7-O7 stack starting from the antipodal point. The inflaton turns out to be a linear combination of the brane position and the axionic partner of the K3 volume modulus, and the similarity of the potential along the inflaton direction with that of racetrack inflation leads to the prediction ns <= 0.95 for the spectral index. The slow roll is insensitive to most of the features of the effective superpotential, and requires a one-in-104 tuning to ensure that the torus is close to square in shape. We also consider D-term inflation with the D3 close to the attractive D7, but find that for a broad (but not exhaustive) class of parameters the conditions for slow roll tend to destabilize the bulk moduli. In contrast to the axionic case, the best inflationary example of this kind requires the delicate adjustment of potential parameters (much more than the part-per-mille level), and gives inflation only at an inflection point of the potential (and so suffers from additional fine-tuning of initial conditions to avoid an overshoot problem).

Numerical Investigation on Absorption Enhancement of Black Carbon Aerosols Partially Coated With Nonabsorbing Organics

NASA Astrophysics Data System (ADS)

Zhang, Xiaolin; Mao, Mao; Yin, Yan; Wang, Bin

2018-01-01

This study numerically evaluates the effects of aerosol microphysics, including coated volume fraction of black carbon (BC), shell/core ratio, and size distribution, on the absorption enhancement (Eab) of polydisperse BC aggregates partially coated by organics, which is calculated by the exact multiple-sphere T-matrix method. The coated volume fraction of BC plays a substantial role in determining the absorption enhancement of partially coated BC aggregates, which typically have an Eab in the range of 1.0-2.0 with a larger value for larger coated volume fraction of BC as the shell/core ratio, BC geometry, and size distribution are fixed. The shell/core ratio, BC geometry, and size distribution have little impact on the Eab of coated BC with small coated volume fraction of BC, while they become significant for large coated volume fraction of BC. The Eab of partially coated BC particles can be slightly less than 1.0 for the large BC in the accumulation mode exhibiting large shell/core ratio and small coated volume fraction of BC, indicating that the absorption shows even slight decrease relative to uncoated BC particles. For partially coated BC aggregates in the accumulation and coarse modes, the refractive index uncertainties of BC result in the Eab differences of less than 9% and 2%, respectively, while those of organics can induce larger variations with the maximum differences up to 22% and 18%, respectively. Our study indicates that accounting for particle coating microphysics, particularly the coated volume fraction of BC, can potentially help to understand the differences in observations of largely variable absorption enhancements over various regions.

In vitro validation of a Pitot-based flow meter for the measurement of respiratory volume and flow in large animal anaesthesia.

PubMed

Moens, Yves P S; Gootjes, Peter; Ionita, Jean-Claude; Heinonen, Erkki; Schatzmann, Urs

2009-05-01

To remodel and validate commercially available monitors and their Pitot tube-based flow sensors for use in large animals, using in vitro techniques. Prospective, in vitro experiment. Both the original and the remodelled sensor were studied with a reference flow generator. Measurements were taken of the static flow-pressure relationship and linearity of the flow signal. Sensor airway resistance was calculated. Following recalibration of the host monitor, volumes ranging from 1 to 7 L were generated by a calibration syringe, and bias and precision of spirometric volume was determined. Where manual recalibration was not available, a conversion factor for volume measurement was determined. The influence of gas composition mixture and peak flow on the conversion factor was studied. Both the original and the remodelled sensor showed similar static flow-pressure relationships and linearity of the flow signal. Mean bias (%) of displayed values compared with the reference volume of 3, 5 and 7 L varied between -0.4% and +2.4%, and this was significantly smaller than that for 1 L (4.8% to +5.0%). Conversion factors for 3, 5 and 7 L were very similar (mean 6.00 +/- 0.2, range 5.91-6.06) and were not significantly influenced by the gas mixture used. Increasing peak flow caused a small decrease in the conversion factor. Volume measurement error and conversion factors for inspiration and expiration were close to identity. The combination of the host monitor with the remodelled flow sensor allowed accurate in vitro measurement of flows and volumes in a range expected during large animal anaesthesia. This combination has potential as a reliable spirometric monitor for use during large animal anaesthesia.

Physiologic mechanisms of circulatory and body fluid losses in weightlessness identified by mathematical modeling

NASA Technical Reports Server (NTRS)

Simanonok, K. E.; Srinivasan, R. S.; Charles, J. B.

1993-01-01

Central volume expansion due to fluid shifts in weightlessness is believed to activate adaptive reflexes which ultimately result in a reduction of the total circulating blood volume. However, the flight data suggests that a central volume overdistention does not persist, in which case some other factor or factors must be responsible for body fluid losses. We used a computer simulation to test the hypothesis that factors other than central volume overdistention are involved in the loss of blood volume and other body fluid volumes observed in weightlessness and in weightless simulations. Additionally, the simulation was used to identify these factors. The results predict that atrial volumes and pressures return to their prebedrest baseline values within the first day of exposure to head down tilt (HDT) as the blood volume is reduced by an elevated urine formation. They indicate that the mechanisms for large and prolonged body fluid losses in weightlessness is red cell hemoconcentration that elevates blood viscosity and peripheral resistance, thereby lowering capillary pressure. This causes a prolonged alteration of the balance of Starling forces, depressing the extracellular fluid volume until the hematocrit is returned to normal through a reduction of the red cell mass, which also allows some restoration of the plasma volume. We conclude that the red cell mass becomes the physiologic driver for a large 'undershoot' of the body fluid volumes after the normalization of atrial volumes and pressures.

New Methods in Non-Perturbative QCD

DOE Office of Scientific and Technical Information (OSTI.GOV)

Unsal, Mithat

2017-01-31

In this work, we investigate the properties of quantum chromodynamics (QCD), by using newly developing mathematics and physics formalisms. Almost all of the mass in the visible universe emerges from a quantum chromodynamics (QCD), which has a completely negligible microscopic mass content. An intimately related issue in QCD is the quark confinement problem. Answers to non-perturbative questions in QCD remained largely elusive despite much effort over the years. It is also believed that the usual perturbation theory is inadequate to address these kinds of problems. Perturbation theory gives a divergent asymptotic series (even when the theory is properly renormalized), andmore » there are non-perturbative phenomena which never appear at any order in perturbation theory. Recently, a fascinating bridge between perturbation theory and non-perturbative effects has been found: a formalism called resurgence theory in mathematics tells us that perturbative data and non-perturbative data are intimately related. Translating this to the language of quantum field theory, it turns out that non-perturbative information is present in a coded form in perturbation theory and it can be decoded. We take advantage of this feature, which is particularly useful to understand some unresolved mysteries of QCD from first principles. In particular, we use: a) Circle compactifications which provide a semi-classical window to study confinement and mass gap problems, and calculable prototypes of the deconfinement phase transition; b) Resurgence theory and transseries which provide a unified framework for perturbative and non-perturbative expansion; c) Analytic continuation of path integrals and Lefschetz thimbles which may be useful to address sign problem in QCD at finite density.« less

A device for controlled jet injection of large volumes of liquid.

PubMed

Mckeage, James W; Ruddy, Bryan P; Nielsen, Poul M F; Taberner, Andrew J

2016-08-01

We present a needle-free jet injection device controllably actuated by a voice coil and capable of injecting up to 1.3 mL. This device is used to perform jet injections of ~900 μL into porcine tissue. This is the first time that delivery of such a large volume has been reported using an electronically controllable device. The controllability of this device is demonstrated with a series of ejections where the desired volume is ejected to within 1 % during an injection at a predetermined jet velocity.

Modified Technique For Chemisorption Measurements

NASA Technical Reports Server (NTRS)

Schryer, David R.; Brown, Kenneth G.; Schryer, Jacqueline

1989-01-01

In measurements of chemisorption of CO on Pt/SnO2 catalyst observed that if small numbers of relatively large volumes of adsorbate gas are passed through sample, very little removal of CO detected. In these cases little or no CO has been chemisorbed on Pt/SnO2. Technique of using large number of small volumes of adsorbate gas to measure chemisorption applicable to many gas/material combinations other than CO on Pt/SnO2. Volume used chosen so that at least 10 percent of adsorbate gas removed during each exposure.

The raft of the Saint-Jean River, Gaspé (Québec, Canada): A dynamic feature trapping most of the wood transported from the catchment

NASA Astrophysics Data System (ADS)

Boivin, Maxime; Buffin-Bélanger, Thomas; Piégay, Hervé

2015-02-01

The rivers of the Gaspé Peninsula, Québec (Canada), a coastal drainage system of the St. Lawrence River, receive and transport vast quantities of large wood. The rapid rate of channel shifting caused by high-energy flows and noncohesive banks allows wood recruitment that in turn greatly influences river dynamics. The delta of the Saint-Jean River has accumulated wood since 1960, leading to frequent avulsions over that time period. The wood raft there is now more than 3-km in length, which is unusual but natural. This jam configuration allows a unique opportunity to estimate a wood budget at the scale of a long river corridor and to better understand the dynamics of large wood (LW) in rivers. A wood budget includes the evaluation of wood volumes (i) produced by bank erosion (input), (ii) still in transit in the river corridor (deposited on sand bars or channel edges), and (iii) accumulated in the delta (output). The budget is based on an analysis of aerial photos dating back to 1963 as well as surveys carried out in 2010, all of which were used to locate and describe large wood accumulations along a 60-km river section. The main results of this paper show that the raft formation in the delta is dynamic and can be massive, but it is a natural process. Considering the estimated wood volume trapped in the delta from 1963 to 2013 (≈ 25,000 m3), two important points are revealed by the quantification of the wood recruitment volume from 1963 to 2004 (≈ 27,000 m3 ± 400 m3) and of the wood volume stored on the bars in 2010 (≈ 5950 m3). First, the recruitment of large wood from lateral migration for the 40-year period can account for the volume of large wood in the delta and in transit. Second, the excess wood volume produced by lateral migration and avulsion represents a minimum estimation of the large wood trapped on the floodplain owing to wood volume that has decomposed and large wood that exited the river system. Rafts are major trapping structures that provide good potential sites to monitor wood delivery from the catchment through time and allow estimations of LW residence time while in transit. These results contribute to understanding the interannual large wood dynamics in the Saint-Jean River and can assist river managers in determining sustainable solutions for coping with the issue of wood rafts in rivers.

Numerical simulation of seismic wave propagation from land-excited large volume air-gun source

NASA Astrophysics Data System (ADS)

Cao, W.; Zhang, W.

2017-12-01

The land-excited large volume air-gun source can be used to study regional underground structures and to detect temporal velocity changes. The air-gun source is characterized by rich low frequency energy (from bubble oscillation, 2-8Hz) and high repeatability. It can be excited in rivers, reservoirs or man-made pool. Numerical simulation of the seismic wave propagation from the air-gun source helps to understand the energy partitioning and characteristics of the waveform records at stations. However, the effective energy recorded at a distance station is from the process of bubble oscillation, which can not be approximated by a single point source. We propose a method to simulate the seismic wave propagation from the land-excited large volume air-gun source by finite difference method. The process can be divided into three parts: bubble oscillation and source coupling, solid-fluid coupling and the propagation in the solid medium. For the first part, the wavelet of the bubble oscillation can be simulated by bubble model. We use wave injection method combining the bubble wavelet with elastic wave equation to achieve the source coupling. Then, the solid-fluid boundary condition is implemented along the water bottom. And the last part is the seismic wave propagation in the solid medium, which can be readily implemented by the finite difference method. Our method can get accuracy waveform of land-excited large volume air-gun source. Based on the above forward modeling technology, we analysis the effect of the excited P wave and the energy of converted S wave due to different water shapes. We study two land-excited large volume air-gun fields, one is Binchuan in Yunnan, and the other is Hutubi in Xinjiang. The station in Binchuan, Yunnan is located in a large irregular reservoir, the waveform records have a clear S wave. Nevertheless, the station in Hutubi, Xinjiang is located in a small man-made pool, the waveform records have very weak S wave. Better understanding of the characteristics of land-excited large volume air-gun can help to better use of the air-gun source.

21 CFR 201.323 - Aluminum in large and small volume parenterals used in total parenteral nutrition.

Code of Federal Regulations, 2011 CFR

2011-04-01

... used in total parenteral nutrition. 201.323 Section 201.323 Food and Drugs FOOD AND DRUG ADMINISTRATION... parenteral nutrition. (a) The aluminum content of large volume parenteral (LVP) drug products used in total parenteral nutrition (TPN) therapy must not exceed 25 micrograms per liter (µg/L). (b) The package insert of...

21 CFR 201.323 - Aluminum in large and small volume parenterals used in total parenteral nutrition.

Code of Federal Regulations, 2012 CFR

2012-04-01

... used in total parenteral nutrition. 201.323 Section 201.323 Food and Drugs FOOD AND DRUG ADMINISTRATION... parenteral nutrition. (a) The aluminum content of large volume parenteral (LVP) drug products used in total parenteral nutrition (TPN) therapy must not exceed 25 micrograms per liter (µg/L). (b) The package insert of...

21 CFR 201.323 - Aluminum in large and small volume parenterals used in total parenteral nutrition.

Code of Federal Regulations, 2013 CFR

2013-04-01

... used in total parenteral nutrition. 201.323 Section 201.323 Food and Drugs FOOD AND DRUG ADMINISTRATION... parenteral nutrition. (a) The aluminum content of large volume parenteral (LVP) drug products used in total parenteral nutrition (TPN) therapy must not exceed 25 micrograms per liter (µg/L). (b) The package insert of...

21 CFR 201.323 - Aluminum in large and small volume parenterals used in total parenteral nutrition.

Code of Federal Regulations, 2010 CFR

2010-04-01

... used in total parenteral nutrition. 201.323 Section 201.323 Food and Drugs FOOD AND DRUG ADMINISTRATION... parenteral nutrition. (a) The aluminum content of large volume parenteral (LVP) drug products used in total parenteral nutrition (TPN) therapy must not exceed 25 micrograms per liter (µg/L). (b) The package insert of...

21 CFR 201.323 - Aluminum in large and small volume parenterals used in total parenteral nutrition.

Code of Federal Regulations, 2014 CFR

2014-04-01

... used in total parenteral nutrition. 201.323 Section 201.323 Food and Drugs FOOD AND DRUG ADMINISTRATION... parenteral nutrition. (a) The aluminum content of large volume parenteral (LVP) drug products used in total parenteral nutrition (TPN) therapy must not exceed 25 micrograms per liter (µg/L). (b) The package insert of...

Effects of large volume injection of aliphatic alcohols as sample diluents on the retention of low hydrophobic solutes in reversed-phase liquid chromatography.

PubMed

David, Victor; Galaon, Toma; Aboul-Enein, Hassan Y

2014-01-03

Recent studies showed that injection of large volume of hydrophobic solvents used as sample diluents could be applied in reversed-phase liquid chromatography (RP-LC). This study reports a systematic research focused on the influence of a series of aliphatic alcohols (from methanol to 1-octanol) on the retention process in RP-LC, when large volumes of sample are injected on the column. Several model analytes with low hydrophobic character were studied by RP-LC process, for mobile phases containing methanol or acetonitrile as organic modifiers in different proportions with aqueous component. It was found that starting with 1-butanol, the aliphatic alcohols can be used as sample solvents and they can be injected in high volumes, but they may influence the retention factor and peak shape of the dissolved solutes. The dependence of the retention factor of the studied analytes on the injection volume of these alcohols is linear, with a decrease of its value as the sample volume is increased. The retention process in case of injecting up to 200μL of upper alcohols is dependent also on the content of the organic modifier (methanol or acetonitrile) in mobile phase. Copyright © 2013 Elsevier B.V. All rights reserved.

Atmospheric energetics in regions of intense convective activity

NASA Technical Reports Server (NTRS)

Fuelberg, H. E.

1977-01-01

Synoptic-scale budgets of kinetic and total potential energy are computed using 3- and 6-h data at nine times from NASA's fourth Atmospheric Variability Experiment (AVE IV). Two intense squall lines occurred during the period. Energy budgets for areas that enclose regions of intense convection are shown to have systematic changes that relate to the life cycles of the convection. Some of the synoptic-scale energy processes associated with the convection are found to be larger than those observed in the vicinity of mature cyclones. Volumes enclosing intense convection are found to have large values of cross-contour conversion of potential to kinetic energy and large horizontal export of kinetic energy. Although small net vertical transport of kinetic energy is observed, values at individual layers indicate large upward transport. Transfer of kinetic energy from grid to subgrid scales of motion occurs in the volumes. Latent heat release is large in the middle and upper troposphere and is thought to be the cause of the observed cyclic changes in the budget terms. Total potential energy is found to be imported horizontally in the lower half of the atmosphere, transported aloft, and then exported horizontally. Although local changes of kinetic energy and total potential energy are small, interaction between volumes enclosing convection with surrounding larger volumes is quite large.

Development of a high resolution stepper motor prototype. Volume 2. Detailed results. Volume 3. Development rapport final relatif a un prototype de moteur pas a pas a grande resolution. Volume 2. Resultats detailles. Volume 3. Developpement. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1975-12-01

This motor could be used to drive large solar panels of future satellites. Results of investigations concerning a breadboard model without a relaxation torque and a prototype with a relaxation torque are presented. For volume 1; see ESR-97066. (GRA)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ellis, John; Evans, Jason L.; Nagata, Natsumi

We reconsider the minimal SU( 5) grand unified theory (GUT) in the context of no-scale supergravity inspired by string compactification scenarios, assuming that the soft supersymmetry-breaking parameters satisfy universality conditions at some input scale M in above the GUT scale M GUT. When setting up such a no-scale super-GUT model, special attention must be paid to avoiding the Scylla of rapid proton decay and the Charybdis of an excessive density of cold dark matter, while also having an acceptable mass for the Higgs boson. Furthermore, we do not find consistent solutions if none of the matter and Higgs fields aremore » assigned to twisted chiral supermultiplets, even in the presence of Giudice–Masiero terms. But, consistent solutions may be found if at least one fiveplet of GUT Higgs fields is assigned to a twisted chiral supermultiplet, with a suitable choice of modular weights. Spin-independent dark matter scattering may be detectable in some of these consistent solutions.« less

Nonlinear multidimensional cosmological models with form fields: Stabilization of extra dimensions and the cosmological constant problem

NASA Astrophysics Data System (ADS)

Günther, U.; Moniz, P.; Zhuk, A.

2003-08-01

We consider multidimensional gravitational models with a nonlinear scalar curvature term and form fields in the action functional. In our scenario it is assumed that the higher dimensional spacetime undergoes a spontaneous compactification to a warped product manifold. Particular attention is paid to models with quadratic scalar curvature terms and a Freund-Rubin-like ansatz for solitonic form fields. It is shown that for certain parameter ranges the extra dimensions are stabilized. In particular, stabilization is possible for any sign of the internal space curvature, the bulk cosmological constant, and of the effective four-dimensional cosmological constant. Moreover, the effective cosmological constant can satisfy the observable limit on the dark energy density. Finally, we discuss the restrictions on the parameters of the considered nonlinear models and how they follow from the connection between the D-dimensional and the four-dimensional fundamental mass scales.

Transdimensional tunneling in the multiverse

DOE Office of Scientific and Technical Information (OSTI.GOV)

Blanco-Pillado, Jose J.; Schwartz-Perlov, Delia; Vilenkin, Alexander, E-mail: jose@cosmos.phy.tufts.edu, E-mail: dperlov@cosmos.phy.tufts.edu, E-mail: vilenkin@cosmos.phy.tufts.edu

2010-05-01

Topology-changing transitions between vacua of different effective dimensionality are studied in the context of a 6-dimensional Einstein-Maxwell theory. The landscape of this theory includes a 6d de Sitter vacuum (dS{sub 6}), a number of dS{sub 4} × S{sub 2} and AdS{sub 4} × S{sub 2} vacua, and a number of AdS{sub 2} × S{sub 4} vacua. We find that compactification transitions dS{sub 6} → AdS{sub 2} × S{sub 4} occur through the nucleation of electrically charged black hole pairs, and transitions from dS{sub 6} to dS{sub 4} × S{sub 2} and AdS{sub 4} × S{sub 2} occur through the nucleationmore » of magnetically charged spherical black branes. We identify the appropriate instantons and describe the spacetime structure resulting from brane nucleation.« less

M-theory superstrata and the MSW string

DOE PAGES

Bena, Iosif; Martinec, Emil; Turton, David; ...

2017-06-26

The low-energy description of wrapped M5 branes in compactifications of M-theory on a Calabi-Yau threefold times a circle is given by a conformal field theory studied by Maldacena, Strominger and Witten and known as the MSW CFT. Taking the threefold to be T 6 or K3×T 2, we construct a map between a sub-sector of this CFT and a sub-sector of the D1-D5 CFT. We demonstrate this map by considering a set of D1-D5 CFT states that have smooth horizonless bulk duals, and explicitly constructing the supergravity solutions dual to the corresponding states of the MSW CFT. We thus obtainmore » the largest known class of solutions dual to MSW CFT microstates, and demonstrate that five-dimensional ungauged supergravity admits much larger families of smooth horizonless solutions than previously known.« less

Constraints on axion inflation from the weak gravity conjecture

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rudelius, Tom, E-mail: rudelius@physics.harvard.edu

2015-09-01

We derive constraints facing models of axion inflation based on decay constant alignment from a string-theoretic and quantum gravitational perspective. In particular, we investigate the prospects for alignment and 'anti-alignment' of C{sub 4} axion decay constants in type IIB string theory, deriving a strict no-go result in the latter case. We discuss the relationship of axion decay constants to the weak gravity conjecture and demonstrate agreement between our string-theoretic constraints and those coming from the 'generalized' weak gravity conjecture. Finally, we consider a particular model of decay constant alignment in which the potential of C{sub 4} axions in type IIBmore » compactifications on a Calabi-Yau three-fold is dominated by contributions from D7-branes, pointing out that this model evades some of the challenges derived earlier in our paper but is highly constrained by other geometric considerations.« less

Constraints on axion inflation from the weak gravity conjecture

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rudelius, Tom

2015-09-08

We derive constraints facing models of axion inflation based on decay constant alignment from a string-theoretic and quantum gravitational perspective. In particular, we investigate the prospects for alignment and ‘anti-alignment’ of C{sub 4} axion decay constants in type IIB string theory, deriving a strict no-go result in the latter case. We discuss the relationship of axion decay constants to the weak gravity conjecture and demonstrate agreement between our string-theoretic constraints and those coming from the ‘generalized’ weak gravity conjecture. Finally, we consider a particular model of decay constant alignment in which the potential of C{sub 4} axions in type IIBmore » compactifications on a Calabi-Yau three-fold is dominated by contributions from D7-branes, pointing out that this model evades some of the challenges derived earlier in our paper but is highly constrained by other geometric considerations.« less

Rotation forms and local Hamiltonian monodromy

NASA Astrophysics Data System (ADS)

Efstathiou, K.; Giacobbe, A.; Mardešić, P.; Sugny, D.

2017-02-01

The monodromy of torus bundles associated with completely integrable systems can be computed using geometric techniques (constructing homology cycles) or analytic arguments (computing discontinuities of abelian integrals). In this article, we give a general approach to the computation of monodromy that resembles the analytical one, reducing the problem to the computation of residues of polar 1-forms. We apply our technique to three celebrated examples of systems with monodromy (the champagne bottle, the spherical pendulum, the hydrogen atom) and to the case of non-degenerate focus-focus singularities, re-obtaining the classical results. An advantage of this approach is that the residue-like formula can be shown to be local in a neighborhood of a singularity, hence allowing the definition of monodromy also in the case of non-compact fibers. This idea has been introduced in the literature under the name of scattering monodromy. We prove the coincidence of the two definitions with the monodromy of an appropriately chosen compactification.

U(1) mediation of flux supersymmetry breaking

NASA Astrophysics Data System (ADS)

Grimm, Thomas W.; Klemm, Albrecht

2008-10-01

We study the mediation of supersymmetry breaking triggered by background fluxes in Type II string compactifications with Script N = 1 supersymmetry. The mediation arises due to an U(1) vector multiplet coupling to both a hidden supersymmetry breaking flux sector and a visible D-brane sector. The required internal manifolds can be constructed by non-Kähler resolutions of singular Calabi-Yau manifolds. The effective action encoding the U(1) coupling is then determined in terms of the global topological properties of the internal space. We investigate suitable local geometries for the hidden and visible sector in detail. This includes a systematic study of orientifold symmetries of del Pezzo surfaces realized in compact geometries after geometric transition. We construct compact examples admitting the key properties to realize flux supersymmetry breaking and U(1) mediation. Their toric realization allows us to analyze the geometry of curve classes and confirm the topological connection between the hidden and visible sector.

Was the Universe actually radiation dominated prior to nucleosynthesis?

NASA Astrophysics Data System (ADS)

Giblin, John T.; Kane, Gordon; Nesbit, Eva; Watson, Scott; Zhao, Yue

2017-08-01

Maybe not. String theory approaches to both beyond the Standard Model and inflationary model building generically predict the existence of scalars (moduli) that are light compared to the scale of quantum gravity. These moduli become displaced from their low energy minima in the early Universe and lead to a prolonged matter-dominated epoch prior to big bang nucleosynthesis (BBN). In this paper, we examine whether nonperturbative effects such as parametric resonance or tachyonic instabilities can shorten, or even eliminate, the moduli condensate and matter-dominated epoch. Such effects depend crucially on the strength of the couplings, and we find that unless the moduli become strongly coupled, the matter-dominated epoch is unavoidable. In particular, we find that in string and M-theory compactifications where the lightest moduli are near the TeV scale, a matter-dominated epoch will persist until the time of big bang nucleosynthesis.

CD volume design and verification

NASA Technical Reports Server (NTRS)

Li, Y. P.; Hughes, J. S.

1993-01-01

In this paper, we describe a prototype for CD-ROM volume design and verification. This prototype allows users to create their own model of CD volumes by modifying a prototypical model. Rule-based verification of the test volumes can then be performed later on against the volume definition. This working prototype has proven the concept of model-driven rule-based design and verification for large quantity of data. The model defined for the CD-ROM volumes becomes a data model as well as an executable specification.

Proceedings of the Space Surveillance Workshop (12th) Held in Lexington, Massachusetts on 5-7 April 1994. Volume 2

DTIC Science & Technology

1994-04-07

detector mated to wide- angle optics to continuously view a large conical volume of space in the vicinity of the orbiting spacecraft . When a debris... large uncertainties. This lack of reliable data for debris particles in the millimeter/centimeter size range presents a problem to spacecraft designers...by smaller particles (<I mm) can be negated by the use of meteor bumpers covering the critical parts of a spacecraft , without incurring too large a

Large volume flow-through scintillating detector

DOEpatents

Gritzo, Russ E.; Fowler, Malcolm M.

1995-01-01

A large volume flow through radiation detector for use in large air flow situations such as incinerator stacks or building air systems comprises a plurality of flat plates made of a scintillating material arranged parallel to the air flow. Each scintillating plate has a light guide attached which transfers light generated inside the scintillating plate to an associated photomultiplier tube. The output of the photomultiplier tubes are connected to electronics which can record any radiation and provide an alarm if appropriate for the application.

Absorption and scattering coefficient dependence of laser-Doppler flowmetry models for large tissue volumes.

PubMed

Binzoni, T; Leung, T S; Rüfenacht, D; Delpy, D T

2006-01-21

Based on quasi-elastic scattering theory (and random walk on a lattice approach), a model of laser-Doppler flowmetry (LDF) has been derived which can be applied to measurements in large tissue volumes (e.g. when the interoptode distance is >30 mm). The model holds for a semi-infinite medium and takes into account the transport-corrected scattering coefficient and the absorption coefficient of the tissue, and the scattering coefficient of the red blood cells. The model holds for anisotropic scattering and for multiple scattering of the photons by the moving scatterers of finite size. In particular, it has also been possible to take into account the simultaneous presence of both Brownian and pure translational movements. An analytical and simplified version of the model has also been derived and its validity investigated, for the case of measurements in human skeletal muscle tissue. It is shown that at large optode spacing it is possible to use the simplified model, taking into account only a 'mean' light pathlength, to predict the blood flow related parameters. It is also demonstrated that the 'classical' blood volume parameter, derived from LDF instruments, may not represent the actual blood volume variations when the investigated tissue volume is large. The simplified model does not need knowledge of the tissue optical parameters and thus should allow the development of very simple and cost-effective LDF hardware.

Chloride Content of Fluids Used for Large-Volume Resuscitation Is Associated With Reduced Survival.

PubMed

Sen, Ayan; Keener, Christopher M; Sileanu, Florentina E; Foldes, Emily; Clermont, Gilles; Murugan, Raghavan; Kellum, John A

2017-02-01

We sought to investigate if the chloride content of fluids used in resuscitation was associated with short- and long-term outcomes. We identified patients who received large-volume fluid resuscitation, defined as greater than 60 mL/kg over a 24-hour period. Chloride load was determined for each patient based on the chloride ion concentration of the fluids they received during large-volume fluid resuscitation multiplied by the volume of fluids. We compared the development of hyperchloremic acidosis, acute kidney injury, and survival among those with higher and lower chloride loads. University Medical Center. Patients admitted to ICUs from 2000 to 2008. None. Among 4,710 patients receiving large-volume fluid resuscitation, hyperchloremic acidosis was documented in 523 (11%). Crude rates of hyperchloremic acidosis, acute kidney injury, and hospital mortality all increased significantly as chloride load increased (p < 0.001). However, chloride load was no longer associated with hyperchloremic acidosis or acute kidney injury after controlling for total fluids, age, and baseline severity. Conversely, each 100 mEq increase in chloride load was associated with a 5.5% increase in the hazard of death even after controlling for total fluid volume, age, and severity (p = 0.0015) over 1 year. Chloride load is associated with significant adverse effects on survival out to 1 year even after controlling for total fluid load, age, and baseline severity of illness. However, the relationship between chloride load and development of hyperchloremic acidosis or acute kidney injury is less clear, and further research is needed to elucidate the mechanisms underlying the adverse effects of chloride load on survival.

Order flow dynamics around extreme price changes on an emerging stock market

NASA Astrophysics Data System (ADS)

Mu, Guo-Hua; Zhou, Wei-Xing; Chen, Wei; Kertész, János

2010-07-01

We study the dynamics of order flows around large intraday price changes using ultra-high-frequency data from the Shenzhen Stock Exchange. We find a significant reversal of price for both intraday price decreases and increases with a permanent price impact. The volatility, the volume of different types of orders, the bid-ask spread and the volume imbalance increase before the extreme events and decay slowly as a power law, which forms a well-established peak. The volume of buy market orders increases faster and the corresponding peak appears earlier than for sell market orders around positive events, while the volume peak of sell market orders leads buy market orders in the magnitude and time around negative events. When orders are divided into four groups according to their aggressiveness, we find that the behaviors of order volume and order number are similar, except for buy limit orders and canceled orders that the peak of order number postpones 2 min later after the peak of order volume, implying that investors placing large orders are more informed and play a central role in large price fluctuations. We also study the relative rates of different types of orders and find differences in the dynamics of relative rates between buy orders and sell orders and between individual investors and institutional investors. There is evidence that institutions behave very differently from individuals and that they have more aggressive strategies. Combining these findings, we conclude that institutional investors are better informed and play a more influential role in driving large price fluctuations.

HIGH VOLUME INJECTION FOR GCMS ANALYSIS OF PARTICULATE ORGANIC SPECIES IN AMBIENT AIR

EPA Science Inventory

Detection of organic species in ambient particulate matter typically requires large air sample volumes, frequently achieved by grouping samples into monthly composites. Decreasing the volume of air sample required would allow shorter collection times and more convenient sample c...

Effects of growth, diving history, and high altitude on blood oxygen capacity in harbor seals

NASA Technical Reports Server (NTRS)

Kodama, A. M.; Elsner, R.; Pace, N.

1977-01-01

Blood volume and body composition for diving and nondiving harbor seals were measured at six-week intervals during a 10-month period of captitivity. Whole body hematocrit, red cell volume per kg of lean body mass, and total circulating hemoglobin per kg lean body mass were significantly higher in the diving group, but relatively large blood volumes expressed in terms of body weight (11-12%) were found in both groups. A pair of harbor seals exposed to high altitude for about three months registered significant increases in red cell volume, blood hemoglobin levels, and blood volume expressed in terms of body weight; results of alveolar gas analyses indicate that hyperventilation also occurred. These typical mammalian responses to hypoxia suggest that the harbor seal's large blood volume and high hemoglobin content are an expression of phylogenetic control, and that in spite of its adaptability to apnea during its diving life, the animal cannot be considered preacclimatized to high altitude.

Worldwide trends in fishing interest indicated by Internet search volume

USGS Publications Warehouse

Wilde, G.R.; Pope, K.L.

2013-01-01

There is a growing body of literature that shows internet search volume on a topic, such as fishing, is a viable measure of salience. Herein, internet search volume for 'fishing' and 'angling' is used as a measure of public interest in fishing, in particular, recreational fishing. An online tool, Google Insights for Search, which allows one to study internet search terms and their volume since 2004, is used to examine trends in interest in fishing for 50 countries. Trends in normalised fishing search volume, during 2004 through 2011, varied from a 72.6% decrease (Russian Federation) to a 133.7% increase (Hungary). Normalised fishing search volume declined in 40 (80%) of the countries studied. The decline has been relatively large in English-speaking countries, but also has been large in Central and South American, and European countries. Analyses of search queries provide a low-cost means of gaining insight into angler interests and, possibly, behaviour in countries around the world.

Application of taxonomy theory, Volume 1: Computing a Hopf bifurcation-related segment of the feasibility boundary. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zaborszky, J.; Venkatasubramanian, V.

1995-10-01

Taxonomy Theory is the first precise comprehensive theory for large power system dynamics modeled in any detail. The motivation for this project is to show that it can be used, practically, for analyzing a disturbance that actually occurred on a large system, which affected a sizable portion of the Midwest with supercritical Hopf type oscillations. This event is well documented and studied. The report first summarizes Taxonomy Theory with an engineering flavor. Then various computational approaches are sighted and analyzed for desirability to use with Taxonomy Theory. Then working equations are developed for computing a segment of the feasibility boundarymore » that bounds the region of (operating) parameters throughout which the operating point can be moved without losing stability. Then experimental software incorporating large EPRI software packages PSAPAC is developed. After a summary of the events during the subject disturbance, numerous large scale computations, up to 7600 buses, are reported. These results are reduced into graphical and tabular forms, which then are analyzed and discussed. The report is divided into two volumes. This volume illustrates the use of the Taxonomy Theory for computing the feasibility boundary and presents evidence that the event indeed led to a Hopf type oscillation on the system. Furthermore it proves that the Feasibility Theory can indeed be used for practical computation work with very large systems. Volume 2, a separate volume, will show that the disturbance has led to a supercritical (that is stable oscillation) Hopf bifurcation.« less

MR-guided noninvasive thermal coagulation of in-vivo liver tissue using ultrasonic phased array

NASA Astrophysics Data System (ADS)

Daum, Douglas R.; Smith, Nadine; McDannold, Nathan; Hynynen, Kullervo H.

1999-05-01

Magnetic resonance (MR) imaging was used to guide and monitor the thermal tissue coagulation of in vivo porcine tissue using a 256 element ultrasonic phased array. The array could coagulate tissue volumes greater than 2 cm3 in liver and 0.5 cm3 in kidney using a single 20 second sonication. This sonication used multiple focus fields which were temporally cycled to heat large tissue volumes simultaneously. Estimates of the coagulated tissue using a thermal dose threshold compare well with T2-weighted images of post sonication lesions. The overlapping large focal volumes could aid in the treatment of large tumor volumes which require multiple overlapping sonications. The ability of MR to detect the presence and undesirable thermal increases at acoustic obstacle such as cartilaginous and bony ribs is demonstrated. This could have a significant impact on the ability to monitor thermal treatments of the liver and other organs which are acoustically blocked.

A self-sampling method to obtain large volumes of undiluted cervicovaginal secretions.

PubMed

Boskey, Elizabeth R; Moench, Thomas R; Hees, Paul S; Cone, Richard A

2003-02-01

Studies of vaginal physiology and pathophysiology sometime require larger volumes of undiluted cervicovaginal secretions than can be obtained by current methods. A convenient method for self-sampling these secretions outside a clinical setting can facilitate such studies of reproductive health. The goal was to develop a vaginal self-sampling method for collecting large volumes of undiluted cervicovaginal secretions. A menstrual collection device (the Instead cup) was inserted briefly into the vagina to collect secretions that were then retrieved from the cup by centrifugation in a 50-ml conical tube. All 16 women asked to perform this procedure found it feasible and acceptable. Among 27 samples, an average of 0.5 g of secretions (range, 0.1-1.5 g) was collected. This is a rapid and convenient self-sampling method for obtaining relatively large volumes of undiluted cervicovaginal secretions. It should prove suitable for a wide range of assays, including those involving sexually transmitted diseases, microbicides, vaginal physiology, immunology, and pathophysiology.

Detection of triazole deicing additives in soil samples from airports with low, mid, and large volume aircraft deicing activities.

PubMed

McNeill, K S; Cancilla, D A

2009-03-01

Soil samples from three USA airports representing low, mid, and large volume users of aircraft deicing fluids (ADAFs) were analyzed by LC/MS/MS for the presence of triazoles, a class of corrosion inhibitors historically used in ADAFs. Triazoles, specifically the 4-methyl-1H-benzotriazole and the 5-methyl-1H-benzotriazole, were detected in a majority of samples and ranged from 2.35 to 424.19 microg/kg. Previous studies have focused primarily on ground and surface water impacts of larger volume ADAF users. The detection of triazoles in soils at low volume ADAF use airports suggests that deicing activities may have a broader environmental impact than previously considered.

Educational Objectives and Academic Performance in Higher Education. Volume 1. Prediction of Academic Performance. Volume 2. Aims and Objectives.

ERIC Educational Resources Information Center

Entwistle, Noel J.; And Others

1977-01-01

Volume 1 discusses a large-scale follow-up study of the correlates of academic success in 2,595 college students. Volume 2 presents a philosophical and historical approach to studying educational objectives. (Available in microfiche from: Carfax Publishing Company, Haddon House, Dorchester-on-Thames, Oxford 0X9 8JZ, England.) (CP)

Infusion System Architecture Impacts the Ability of Intensive Care Nurses to Maintain Hemodynamic Stability in a Living Swine Simulator.

PubMed

Pezone, Matthew J; Peterfreund, Robert A; Maslov, Mikhail Y; Govindaswamy, Radhika R; Lovich, Mark A

2016-05-01

The authors have previously shown that drug infusion systems with large common volumes exhibit long delays in reaching steady-state drug delivery and pharmacodynamic effects compared with smaller common-volume systems. The authors hypothesized that such delays can impede the pharmacologic restoration of hemodynamic stability. The authors created a living swine simulator of hemodynamic instability in which occlusion balloons in the aorta and inferior vena cava (IVC) were used to manipulate blood pressure. Experienced intensive care unit nurses blinded to the use of small or large common-volume infusion systems were instructed to maintain mean arterial blood pressure between 70 and 90 mmHg using only sodium nitroprusside and norepinephrine infusions. Four conditions (IVC or aortic occlusions and small or large common volume) were tested 12 times in eight animals. After aortic occlusion, the time to restore mean arterial pressure to range (t1: 2.4 ± 1.4 vs. 5.0 ± 2.3 min, P = 0.003, average ± SD), time-out-of-range (tOR: 6.2 ± 3.5 vs. 9.5 ± 3.4 min, P = 0.028), and area-out-of-range (pressure-time integral: 84 ± 47 vs. 170 ± 100 mmHg · min, P = 0.018) were all lower with smaller common volumes. After IVC occlusion, t1 (3.7 ± 2.2 vs. 7.1 ± 2.6 min, P = 0.002), tOR (6.3 ± 3.5 vs. 11 ± 3.0 min, P = 0.007), and area-out-of-range (110 ± 93 vs. 270 ± 140 mmHg · min, P = 0.003) were all lower with smaller common volumes. Common-volume size did not impact the total amount infused of either drug. Nurses did not respond as effectively to hemodynamic instability when drugs flowed through large common-volume infusion systems. These findings suggest that drug infusion system common volume may have clinical impact, should be minimized to the greatest extent possible, and warrants clinical investigations.

An interfaces approach to TES ground data system processing design with the Science Investigator-led Processing System (SIPS)

NASA Technical Reports Server (NTRS)

Kurian, R.; Grifin, A.

2002-01-01

Developing production-quality software to process the large volumes of scientific data is the responsibility of the TES Ground Data System, which is being developed at the Jet Propulsion Laboratory together with support contractor Raytheon/ITSS. The large data volume and processing requirements of the TES pose significant challenges to the design.

Research on volume metrology method of large vertical energy storage tank based on internal electro-optical distance-ranging method

NASA Astrophysics Data System (ADS)

Hao, Huadong; Shi, Haolei; Yi, Pengju; Liu, Ying; Li, Cunjun; Li, Shuguang

2018-01-01

A Volume Metrology method based on Internal Electro-optical Distance-ranging method is established for large vertical energy storage tank. After analyzing the vertical tank volume calculation mathematical model, the key processing algorithms, such as gross error elimination, filtering, streamline, and radius calculation are studied for the point cloud data. The corresponding volume values are automatically calculated in the different liquids by calculating the cross-sectional area along the horizontal direction and integrating from vertical direction. To design the comparison system, a vertical tank which the nominal capacity is 20,000 m3 is selected as the research object, and there are shown that the method has good repeatability and reproducibility. Through using the conventional capacity measurement method as reference, the relative deviation of calculated volume is less than 0.1%, meeting the measurement requirements. And the feasibility and effectiveness are demonstrated.

Enhanced FIB-SEM systems for large-volume 3D imaging.

PubMed

Xu, C Shan; Hayworth, Kenneth J; Lu, Zhiyuan; Grob, Patricia; Hassan, Ahmed M; García-Cerdán, José G; Niyogi, Krishna K; Nogales, Eva; Weinberg, Richard J; Hess, Harald F

2017-05-13

Focused Ion Beam Scanning Electron Microscopy (FIB-SEM) can automatically generate 3D images with superior z-axis resolution, yielding data that needs minimal image registration and related post-processing. Obstacles blocking wider adoption of FIB-SEM include slow imaging speed and lack of long-term system stability, which caps the maximum possible acquisition volume. Here, we present techniques that accelerate image acquisition while greatly improving FIB-SEM reliability, allowing the system to operate for months and generating continuously imaged volumes > 10 6 µm 3 . These volumes are large enough for connectomics, where the excellent z resolution can help in tracing of small neuronal processes and accelerate the tedious and time-consuming human proofreading effort. Even higher resolution can be achieved on smaller volumes. We present example data sets from mammalian neural tissue, Drosophila brain, and Chlamydomonas reinhardtii to illustrate the power of this novel high-resolution technique to address questions in both connectomics and cell biology.

Bladder filling variation during conformal radiotherapy for rectal cancer

NASA Astrophysics Data System (ADS)

Sithamparam, S.; Ahmad, R.; Sabarudin, A.; Othman, Z.; Ismail, M.

2017-05-01

Conformal radiotherapy for rectal cancer is associated with small bowel toxicity mainly diarrhea. Treating patients with a full bladder is one of the practical solutions to reduce small bowel toxicity. Previous studies on prostate and cervix cancer patients revealed that maintaining consistent bladder volume throughout radiotherapy treatment is challenging. The aim of this study was to measure bladder volume variation throughout radiotherapy treatment. This study also measured the association between bladder volume changes and diarrhea. Twenty two rectal cancer patients were recruited prospectively. Patients were planned for treatment with full bladder following departmental bladder filling protocol and the planning bladder volume was measured during CT-simulation. During radiotherapy, the bladder volume was measured weekly using cone-beam computed tomography (CBCT) and compared to planning bladder volume. Incidence and severity of diarrhea were recorded during the weekly patient review. There was a negative time trend for bladder volume throughout five weeks treatment. The mean bladder volume decreased 18 % from 123 mL (SD 54 mL) during CT-simulation to 101 mL (SD 71 mL) on the 5th week of radiotherapy, but the decrease is not statistically significant. However, there was a large variation of bladder volume within each patient during treatment. This study showed an association between changes of bladder volume and diarrhea (P = 0.045). In conclusion bladder volume reduced throughout radiotherapy treatment for conformal radiotherapy for rectal cancer and there was a large variation of bladder volume within patients.

Distributed shared memory for roaming large volumes.

PubMed

Castanié, Laurent; Mion, Christophe; Cavin, Xavier; Lévy, Bruno

2006-01-01

We present a cluster-based volume rendering system for roaming very large volumes. This system allows to move a gigabyte-sized probe inside a total volume of several tens or hundreds of gigabytes in real-time. While the size of the probe is limited by the total amount of texture memory on the cluster, the size of the total data set has no theoretical limit. The cluster is used as a distributed graphics processing unit that both aggregates graphics power and graphics memory. A hardware-accelerated volume renderer runs in parallel on the cluster nodes and the final image compositing is implemented using a pipelined sort-last rendering algorithm. Meanwhile, volume bricking and volume paging allow efficient data caching. On each rendering node, a distributed hierarchical cache system implements a global software-based distributed shared memory on the cluster. In case of a cache miss, this system first checks page residency on the other cluster nodes instead of directly accessing local disks. Using two Gigabit Ethernet network interfaces per node, we accelerate data fetching by a factor of 4 compared to directly accessing local disks. The system also implements asynchronous disk access and texture loading, which makes it possible to overlap data loading, volume slicing and rendering for optimal volume roaming.

Local D3/D7 μ-SPLIT SUSY, 125 GeV Higgs and Large Volume Ricci-Flat Swiss-Cheese Metrics:. a Brief Review

NASA Astrophysics Data System (ADS)

Misra, Aalok

In this paper, we review briefly recent progress made in realizing local(ized around a mobile spacetime filling D3-brane in) D3/D7 μ-split Supersymmetry in (the large volume limit of Type IIB) String Theory (compactified on Swiss-Cheese Calabi-Yau orientifolds) as well as obtaining a 125 GeV (light) Higgs in the same setup. We also discuss obtaining the geometric Kähler potential (and hence the Ricci-flat metric) for the Swiss-Cheese Calabi-Yau in the large volume limit using the Donaldson's algorithm and intuition from GLSM-based calculations — we present new results for Swiss-Cheese Calabi-Yau (used in the setup) metrics at points finitely away from the "big" divisor.

Simulation of hydrodynamics using large eddy simulation-second-order moment model in circulating fluidized beds

NASA Astrophysics Data System (ADS)

Juhui, Chen; Yanjia, Tang; Dan, Li; Pengfei, Xu; Huilin, Lu

2013-07-01

Flow behavior of gas and particles is predicted by the large eddy simulation of gas-second order moment of solid model (LES-SOM model) in the simulation of flow behavior in CFB. This study shows that the simulated solid volume fractions along height using a two-dimensional model are in agreement with experiments. The velocity, volume fraction and second-order moments of particles are computed. The second-order moments of clusters are calculated. The solid volume fraction, velocity and second order moments are compared at the three different model constants.

Five-dimensional Yang-Mills-Einstein supergravity on orbifold spacetimes: From phenomenology to M -theory

NASA Astrophysics Data System (ADS)

McReynolds, Sean

Five-dimensional N = 2 Yang-Mills-Einstein supergravity and its couplings to hyper and tensor multiplets are considered on an orbifold spacetime of the form M4 x S1/Gamma, where Gamma is a discrete group. As is well known in such cases, supersymmetry is broken to N = 1 on the orbifold fixed planes, and chiral 4D theories can be obtained from bulk hypermultiplets (or from the coupling of fixed-plane supported fields). Five-dimensional gauge symmetries are broken by boundary conditions for the fields, which are equivalent to some set of Gamma-parity assignments in the orbifold theory, allowing for arbitrary rank reduction. Furthermore, Wilson lines looping from one boundary to the other can break bulk gauge groups, or give rise to vacuum expectation values for scalars on the boundaries, which can result in spontaneous breaking of boundary gauge groups. The broken gauge symmetries do not survive as global symmetries of the low energy theories below the compactification scale due to 4 D minimal couplings to gauge fields. Axionic fields are a generic feature, just as in any compactification of M-theory (or string theory for that matter), and we exhibit the form of this field and its role as the QCD axion, capable of resolving the strong CP problem. The main motivation for the orbifold theories here is taken to be orbifold-GUTS, wherein a unified gauge group is sought in higher dimensions while allowing the orbifold reduction to handle problems such as rapid proton decay, exotic matter, mass hierarchies, etc. To that end, we discuss the allowable minimal SU(5), SO(10) and E6 GUT theories with all fields living in five dimensions. It is argued that, within the class of homogeneous quaternionic scalar manifolds characterizing the hypermultiplet couplings in 5D, supergravity admits a restricted set of theories that yield minimal phenomenological field content. In addition, non-compact gaugings are a novel feature of supergravity theories, and in particular we consider the example of an SU(5,1) YMESGT in which all of the fields of the theory are connected by local (susy and gauge) transformations that are symmetries of the Lagrangian. Such non-compact gaugings allow a novel type of gauge-Higgs unification in higher dimensions. The possibility of boundary-localized fields is considered only via anomaly arguments. (Abstract shortened by UMI.)

Serial volumetric assessment of large for size liver grafts after whole cadaveric liver transplant in adults: do large liver grafts shrink in size?

PubMed

Bekheit, Mohamed; Rajakannu, Muthukumarassamy; Bucur, Petru; Adam, Rene; SaCunha, Antonio; Castaing, Denis; Cherqui, Daniel; Vibert, Eric

2016-02-01

After whole graft orthotopic liver transplantation (OLT), adaptation of the large grafts' volume to recipient weight is widely accepted despite the paucity of evidence on this subject. Thirty nine patients with GRWR > 2.5% were included in this study and subsequently divided into two groups with 3 ≥ GRWR > 3%. Patients had CT scans at three predetermined time points after OLT used for measuring the liver volume. The objective of this study is to evaluate the volumetric changes of whole large liver grafts after adult OLT. At LT, the mean graft recipient body weight ratio (GRWR) was 3.1 ± 0.4%. The mean liver weight was 1881 ± 68 g at LT, 2014 ± 99 ml at one week, 1725 ± 126 ml at 3 months, and 1632 ± 117 (ml) at >6 months. There is an initial increase at 1 week after LT and a subsequent decrease of liver volume on later measurements. None of the late volume measurements were significantly different from the initial graft volume at liver transplant in pair wise comparisons ANOVA repeated measures (p > 0.05). Similarly, the mean GRWR did not change significantly between the initial calculation at transplantation date and the subsequent measurements during the different study time points (F = 0.04, p = 0.96) with a mean of 3.1% (95% CI = 2.2-4.2). AUC ROC discriminated a cutoff of 3% for the initial GRWR above which grafts tend to decrease in size over time (c statistics = 0.74, p = 0.036). In a Clustered ANOVA repeated measures, there was no significant difference in the changes of liver volume between both groups. However, patients with GRWR > 3 showed a trend towards a latent reduction in volume over the tracing period. There was a tendency, but none significant; towards a higher bilirubin, AST, ALT levels over the first postoperative days in recipients with GRWR > 3. Large grafts do not significantly decrease in size. Nonetheless, grafts weighing >3% of the GRWR show a different trend towards decrease in size over time. Copyright © 2015. Published by Elsevier Ltd.

Large-volume iodinated contrast medium extravasation: low frequency and good outcome after conservative management in a single-centre cohort of more than 67,000 patients.

PubMed

Ko, Chih-Hsiang; Tay, Shee Yen; Chang, Hsiu-Chin; Chan, Wing P

2018-06-12

Our aim was to retrospectively investigate the frequency and outcome of large-volume iodinated contrast medium (CM) extravasation in our institution and to compare our management protocol to current practice. Institutional review board approval was obtained, and informed consent was waived because the study was retrospective. From January 2008 to September 2016, radiological examinations with intravenous non-ionic iodinated CM administration were performed in 67,129 patients. Contrast medium extravasation events on CT scans and intravenous pyelograms but not on angiograms were included. All data were collected prospectively and stratified according to age, injection method (manual vs auto-injection), prevention of extravasation by various means (including intercom alarm), management of extravasation (routine application of silver sulfadiazine ointment, clobetasol propionate cream, and damp gauze at room temperature), etc. RESULTS: The incidence of large-volume CM extravasation was very low (0.04% [27/67,129] overall; 0.03% related to manual injection [age range, 59-92 years; mean, 75.4 years], and 0.045% related to auto-injection [age range, 36-86 years; mean, 65.8 years]). The CM extravasation volume in majority of patients was 20-40 ml in 5 of 9 patients (55.6%) in the manual injection group and 14 of 18 (77.8%) in the auto-injection group. Swelling and pain were the most common symptoms. No patient developed severe signs or needed surgical intervention. Results show a very low incidence of large-volume CM extravasation without severe complications or sequelae. The casual effect between our protocols and good outcome cannot be scrutinised thoroughly because the study lacks a control group and is retrospective. • The incidence of large-volume contrast medium extravasation (≥20 ml) was 0.04%. • No patient needed surgical intervention, and most recovered within 7 days. • Each element of our management protocol contributed to good outcome.

Organisational and extraorganisational determinants of volume of service delivery by English community pharmacies: a cross-sectional survey and secondary data analysis.

PubMed

Hann, Mark; Schafheutle, Ellen I; Bradley, Fay; Elvey, Rebecca; Wagner, Andrew; Halsall, Devina; Hassell, Karen; Jacobs, Sally

2017-10-10

This study aimed to identify the organisational and extraorganisational factors associated with existing variation in the volume of services delivered by community pharmacies. Linear and ordered logistic regression of linked national data from secondary sources-community pharmacy activity, socioeconomic and health need datasets-and primary data from a questionnaire survey of community pharmacies in nine diverse geographical areas in England. Annual dispensing volume; annual volume of medicines use reviews (MURs). National dataset (n=10 454 pharmacies): greater dispensing volume was significantly associated with pharmacy ownership type (large chains>independents>supermarkets), greater deprivation, higher local prevalence of cardiovascular disease and depression, older people (aged >75 years) and infants (aged 0-4 years) but lower prevalence of mental health conditions. Greater volume of MURs was significantly associated with pharmacy ownership type (large chains/supermarkets>independents), greater dispensing volume, and lower disease prevalence.Survey dataset (n=285 pharmacies; response=34.6%): greater dispensing volume was significantly associated with staffing, skill-mix, organisational culture, years open and greater deprivation. Greater MUR volume was significantly associated with pharmacy ownership type (large chains/supermarkets>independents), greater dispensing volume, weekly opening hours and lower asthma prevalence. Organisational and extraorganisational factors were found to impact differently on dispensing volume and MUR activity, the latter being driven more by corporate ownership than population need. While levels of staffing and skill-mix were associated with dispensing volume, they did not influence MUR activity. Despite recent changes to the contractual framework, the existing fee-for-service reimbursement may therefore not be the most appropriate for the delivery of cognitive (rather than supply) services, still appearing to incentivise quantity over the quality (in terms of appropriate targeting) of services delivered. Future research should focus on the development of quality measures that could be incorporated into community pharmacy reimbursement mechanisms. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Large volume multiple-path nuclear pumped laser

NASA Technical Reports Server (NTRS)

Hohl, F.; Deyoung, R. J. (Inventor)

1981-01-01

Large volumes of gas are excited by using internal high reflectance mirrors that are arranged so that the optical path crosses back and forth through the excited gaseous medium. By adjusting the external dielectric mirrors of the laser, the number of paths through the laser cavity can be varied. Output powers were obtained that are substantially higher than the output powers of previous nuclear laser systems.

Large-Scale Operations Management Test of Use of the White Amur for Control of Problem Aquatic Plants. Report 4. Third Year Poststocking Results. Volume VI. The Water and Sediment Quality of Lake Conway, Florida.

DTIC Science & Technology

1983-01-01

RAI-RI247443 LARGE-SCALE OPERATIONS MANAGEMENT TEST OF USE OF THE i/i UNITE AMUR FOR CONTR.. (U) MILLER RND MILLER INC ORLANDO FL H D MILLER ET RL...LARGE-SCALE OPERATIONS MANAGEMENT TEST OF USE OF THE WHITE AMUR FOR CONTROL OF PROBLEM AQUATIC PLANTS Report 1: Baseline Studies Volume I...Boyd, J. 1983. "Large-Scale Operations Management Test of Use of the White Amur for Control of Problem Aquatic Plants; Report 4, Third Year Poststocking

Effects of pleural effusion drainage on oxygenation, respiratory mechanics, and hemodynamics in mechanically ventilated patients.

PubMed

Razazi, Keyvan; Thille, Arnaud W; Carteaux, Guillaume; Beji, Olfa; Brun-Buisson, Christian; Brochard, Laurent; Mekontso Dessap, Armand

2014-09-01

In mechanically ventilated patients, the effect of draining pleural effusion on oxygenation is controversial. We investigated the effect of large pleural effusion drainage on oxygenation, respiratory function (including lung volumes), and hemodynamics in mechanically ventilated patients after ultrasound-guided drainage. Arterial blood gases, respiratory mechanics (airway, pleural and transpulmonary pressures, end-expiratory lung volume, respiratory system compliance and resistance), and hemodynamics (blood pressure, heart rate, and cardiac output) were recorded before and at 3 and 24 hours (H24) after pleural drainage. The respiratory settings were kept identical during the study period. The mean volume of effusion drained was 1,579 ± 684 ml at H24. Uncomplicated pneumothorax occurred in two patients. Respiratory mechanics significantly improved after drainage, with a decrease in plateau pressure and a large increase in end-expiratory transpulmonary pressure. Respiratory system compliance, end-expiratory lung volume, and PaO2/FiO2 ratio all improved. Hemodynamics were not influenced by drainage. Improvement in the PaO2/FiO2 ratio from baseline to H24 was positively correlated with the increase in end-expiratory lung volume during the same time frame (r = 0.52, P = 0.033), but not with drained volume. A high value of pleural pressure or a highly negative transpulmonary pressure at baseline predicted limited lung expansion following effusion drainage. A lesser improvement in oxygenation occurred in patients with ARDS. Drainage of large (≥500 ml) pleural effusion in mechanically ventilated patients improves oxygenation and end-expiratory lung volume. Oxygenation improvement correlated with an increase in lung volume and a decrease in transpulmonary pressure, but was less so in patients with ARDS.

Accessibility and Analysis to NASA's New Large Volume Missions

NASA Astrophysics Data System (ADS)

Hausman, J.; Gangl, M.; McAuley, J.; Toaz, R., Jr.

2016-12-01

Each new satellite mission continues to measure larger volumes of data than the last. This is especially true with the new NASA satellite missions NISAR and SWOT, launching in 2020 and 2021, which will produce petabytes of data a year. A major concern is how will users be able to analyze such volumes? This presentation will show how cloud storage and analysis can help overcome and accommodate multiple users' needs. While users may only need gigabytes of data for their research, the data center will need to leverage the processing power of the cloud to perform search and subsetting capabilities over the large volume of data. There is also a vast array of user types that require different tools and services to access and analyze the data. Some users need global data to run climate models, while others require small, dynamic regions with lots of analysis and transformations. There will also be a need to generate data that have different inputs or correction algorithms that the project may not be able to provide as those will be very specialized for specific regions or evolve quicker than what the project can reprocess. By having the data and tools side by side, users will be able to access the data they require and analyze it all in one place. By placing data in the cloud, users can analyze the data there, shifting the current "download and analyze" paradigm to "log-in and analyze". The cloud will provide adequate processing power needed to analyze large volumes of data, subset small regions over large volumes of data, and regenerate/reformat data to the specificity each user requires.

Spatial considerations during cryopreservation of a large volume sample.

PubMed

Kilbride, Peter; Lamb, Stephen; Milne, Stuart; Gibbons, Stephanie; Erro, Eloy; Bundy, James; Selden, Clare; Fuller, Barry; Morris, John

2016-08-01

There have been relatively few studies on the implications of the physical conditions experienced by cells during large volume (litres) cryopreservation - most studies have focused on the problem of cryopreservation of smaller volumes, typically up to 2 ml. This study explores the effects of ice growth by progressive solidification, generally seen during larger scale cryopreservation, on encapsulated liver hepatocyte spheroids, and it develops a method to reliably sample different regions across the frozen cores of samples experiencing progressive solidification. These issues are examined in the context of a Bioartificial Liver Device which requires cryopreservation of a 2 L volume in a strict cylindrical geometry for optimal clinical delivery. Progressive solidification cannot be avoided in this arrangement. In such a system optimal cryoprotectant concentrations and cooling rates are known. However, applying these parameters to a large volume is challenging due to the thermal mass and subsequent thermal lag. The specific impact of this to the cryopreservation outcome is required. Under conditions of progressive solidification, the spatial location of Encapsulated Liver Spheroids had a strong impact on post-thaw recovery. Cells in areas first and last to solidify demonstrated significantly impaired post-thaw function, whereas areas solidifying through the majority of the process exhibited higher post-thaw outcome. It was also found that samples where the ice thawed more rapidly had greater post-thaw viability 24 h post-thaw (75.7 ± 3.9% and 62.0 ± 7.2% respectively). These findings have implications for the cryopreservation of large volumes with a rigid shape and for the cryopreservation of a Bioartificial Liver Device. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

Evidence for Decreased Brain Parenchymal Volume After Large Intracerebral Hemorrhages: a Potential Mechanism Limiting Intracranial Pressure Rises.

PubMed

Williamson, Michael R; Colbourne, Frederick

2017-08-01

Potentially fatal intracranial pressure (ICP) rises commonly occur after large intracerebral hemorrhages (ICH). We monitored ICP after infusing 100-160 μL of autologous blood (vs. 0 μL control) into the striatum of rats in order to test the validity of this common model with regard to ICP elevations. Other endpoints included body temperature, behavioral impairment, lesion volume, and edema. Also, we evaluated hippocampal CA1 sector and somatosensory cortical neuron morphology to assess whether global ischemic injury occurred. Despite massive blood infusions, ICP only modestly increased (160 μL 10.8 ± 2.1 mmHg for <36 h vs. control 3.4 ± 0.5 mmHg), with little peri-hematoma edema at 3 days. Body temperature was not affected. Behavioral deficits and tissue loss were infusion volume-dependent. There was no histological evidence of hippocampal or cortical injury, indicating that cell death was confined to the hematoma and closely surrounding tissue. Surprisingly, the most severe hemorrhages significantly increased cell density (~15-20%) and reduced cell body size (~30%) in regions outside the injury site. Additionally, decreased cell size and increased density were observed after collagenase-induced ICH. Parenchymal volume is seemingly reduced after large ICH. Thus, in addition to well-known compliance mechanisms (e.g., displacement of cerebrospinal fluid and cerebral blood), reduced brain parenchymal volume appears to limit ICP rises in rodents with very large mass lesions.

Large-Scale High-Resolution Cylinder Wake Measurements in a Wind Tunnel using Tomographic PIV with sCMOS Cameras

NASA Astrophysics Data System (ADS)

Michaelis, Dirk; Schroeder, Andreas

2012-11-01

Tomographic PIV has triggered vivid activity, reflected in a large number of publications, covering both: development of the technique and a wide range of fluid dynamic experiments. Maturing of tomo PIV allows the application in medium to large scale wind tunnels. Limiting factor for wind tunnel application is the small size of the measurement volume, being typically about of 50 × 50 × 15 mm3. Aim of this study is the optimization towards large measurement volumes and high spatial resolution performing cylinder wake measurements in a 1 meter wind tunnel. Main limiting factors for the volume size are the laser power and the camera sensitivity. So, a high power laser with 800 mJ per pulse is used together with low noise sCMOS cameras, mounted in forward scattering direction to gain intensity due to the Mie scattering characteristics. A mirror is used to bounce the light back, to have all cameras in forward scattering. Achievable particle density is growing with number of cameras, so eight cameras are used for a high spatial resolution. Optimizations lead to volume size of 230 × 200 × 52 mm3 = 2392 cm3, more than 60 times larger than previously. 281 × 323 × 68 vectors are calculated with spacing of 0.76 mm. The achieved measurement volume size and spatial resolution is regarded as a major step forward in the application of tomo PIV in wind tunnels. Supported by EU-project: no. 265695.

Effects of exchanged cation on the microporosity of montmorillonite

USGS Publications Warehouse

Rutherford, David W.; Chiou, Cary T.; Eberl, Dennis D.

1997-01-01

The micropore volumes of 2 montmorillonites (SAz-1 and SWy-1), each exchanged with Ca, Na, K, Cs and tetramethylammonium (TMA) ions, were calculated from the measured vapor adsorption data of N2 and neo-hexane by use of t- and αs-plots. The corresponding surface areas of the exchanged clays were determined from Brunauer-Emmett-Teller (BET) plots of N2 adsorption data. Micropore volumes and surface areas of the samples increased with the size of exchanged cation: TMA > Cs > K > Ca > Na. The SAz-1 exchanged clays showed generally greater micropore volumes and surface areas than the corresponding SWy-1 clays. The vapor adsorption data and d(001) measurements for dry clay samples were used together to evaluate the likely locations and accessibility of clay micropores, especially the relative accessibility of their interlayer spacing. For both source clays exchanged with Na, Ca and K ions, the interlayer spacing appeared to be too small to admit nonpolar gases and the accessible micropores appeared to have dimensions greater than 5.0 Å, the limiting molecular dimension of neo-hexane. In these systems, there was a good consistency of micropore volumes detected by N2 and neo-hexane. When the clays were intercalated with relatively large cations (TMA and possibly Cs), the large layer expansion created additional microporosity, which was more readily accessible to small N2 than to relatively large neo-hexane. Hence, the micropore volume as detected by N2 was greater than that detected by neo-hexane. The micropore volumes with pore dimensions greater than 5 Å determined for clays exchanged with Na, Ca and K likely resulted from the pores on particle edges and void created by overlap regions of layers. The increase in micropore volumes with pore dimensions less than 5 Å determined for clays exchanged with TMA and possibly Cs could be caused by opening of the interlayer region by the intercalation of these large cations.

Novel three-dimensional imaging volumetry in autosomal dominant polycystic kidney disease: comparison with 2D volumetry.

PubMed

Shin, Dongsuk; Lee, Kyu-Beck; Hyun, Young Youl; Lee, Young Rae; Hwang, Young-Hwan; Park, Hayne Cho; Ahn, Curie

2014-08-01

Autosomal dominant polycystic kidney disease (ADPKD) volumetry is an important marker for evaluating the progression of disease. Three-dimensional (3D) volumetry is generally more timesaving than 2D volumetry, but its reliability and accuracy are uncertain. Small and large phantoms simulating polycystic kidneys and 20 patients with ADPKD underwent magnetic resonance imaging (MRI) volumetry. We evaluated the total kidney volume (TKV) and total cyst volume (TCV) using a novel 3D volumetry program (XelisTM) and compared 3D volumetry data with the conventional 2D method (the reference volume values). After upload and threshold setting, the other organs surrounding the kidney were removed by picking and sculpting. The novel method involves drawing of the kidney or cyst and automatic measurement of kidney volume and cyst volume in 3D images. The 3D volume estimation of the small and large phantoms differed from the actual values by 6.9% and -8.2%, respectively, for TKV and by 2.1% and 1.4% for TCV. In ADPKD patients, the intra-reader reliability of 3D volumetry was 30 ± 180 mL (1.3 ± 10.3%) and 25 ± 113 mL (1.2 ± 9.4%), respectively, for TKV and TCV. Correlation between 3D volumetry and 2D volumetry of TKV and TCV resulted in a high correlation coefficient and a regression slope approaching 1.00 (r = 0.97 - 0.98). The mean of the volume percentage differences for 3D vs. 2D for TKV : TCV were -6.0 ± 8.9% : 2.0 ± 11.8% in large ADPKD and -16.1 ± 10.4% : 13.2 ± 21.9% in small ADPKD. Our study showed that 3D volumetry has reliability and accuracy compared with 2D volumetry in ADPKD. 3D volumetry is more accurate for TCV and large ADPKD.

Low current plasmatron fuel converter having enlarged volume discharges

DOEpatents

Rabinovich, Alexander; Alexeev, Nikolai; Bromberg, Leslie; Cohn, Daniel R.; Samokhin, Andrei

2005-04-19

A novel apparatus and method is disclosed for a plasmatron fuel converter (""plasmatron"") that efficiently uses electrical energy to produce hydrogen rich gas. The volume and shape of the plasma discharge is controlled by a fluid flow established in a plasma discharge volume. A plasmatron according to this invention produces a substantially large effective plasma discharge volume allowing for substantially greater volumetric efficiency in the initiation of chemical reactions within a volume of bulk fluid reactant flowing through the plasmatron.

Low current plasmatron fuel converter having enlarged volume discharges

DOEpatents

Rabinovich, Alexander [Swampscott, MA; Alexeev, Nikolai [Moscow, RU; Bromberg, Leslie [Sharon, MA; Cohn, Daniel R [Chestnut Hill, MA; Samokhin, Andrei [Moscow, RU

2009-10-06

A novel apparatus and method is disclosed for a plasmatron fuel converter ("plasmatron") that efficiently uses electrical energy to produce hydrogen rich gas. The volume and shape of the plasma discharge is controlled by a fluid flow established in a plasma discharge volume. A plasmatron according to this invention produces a substantially large effective plasma discharge volume allowing for substantially greater volumetric efficiency in the initiation of chemical reactions within a volume of bulk fluid reactant flowing through the plasmatron.

Strain heating in process zones; implications for metamorphism and partial melting in the lithosphere

NASA Astrophysics Data System (ADS)

Devès, Maud H.; Tait, Stephen R.; King, Geoffrey C. P.; Grandin, Raphaël

2014-05-01

Since the late 1970s, most earth scientists have discounted the plausibility of melting by shear-strain heating because temperature-dependent creep rheology leads to negative feedback and self-regulation. This paper presents a new model of distributed shear-strain heating that can account for the genesis of large volumes of magmas in both the crust and the mantle of the lithosphere. The kinematic (geometry and rates) frustration associated with incompatible fault junctions (e.g. triple-junction) prevents localisation of all strain on the major faults. Instead, deformation distributes off the main faults forming a large process zone that deforms still at high rates under both brittle and ductile conditions. The increased size of the shear-heated region minimises conductive heat loss, compared with that commonly associated with narrow shear zones, thus promoting strong heating and melting under reasonable rheological assumptions. Given the large volume of the heated zone, large volumes of melt can be generated even at small melt fractions.

Coupling of RF antennas to large volume helicon plasma

NASA Astrophysics Data System (ADS)

Chang, Lei; Hu, Xinyue; Gao, Lei; Chen, Wei; Wu, Xianming; Sun, Xinfeng; Hu, Ning; Huang, Chongxiang

2018-04-01

Large volume helicon plasma sources are of particular interest for large scale semiconductor processing, high power plasma propulsion and recently plasma-material interaction under fusion conditions. This work is devoted to studying the coupling of four typical RF antennas to helicon plasma with infinite length and diameter of 0.5 m, and exploring its frequency dependence in the range of 13.56-70 MHz for coupling optimization. It is found that loop antenna is more efficient than half helix, Boswell and Nagoya III antennas for power absorption; radially parabolic density profile overwhelms Gaussian density profile in terms of antenna coupling for low-density plasma, but the superiority reverses for high-density plasma. Increasing the driving frequency results in power absorption more near plasma edge, but the overall power absorption increases with frequency. Perpendicular stream plots of wave magnetic field, wave electric field and perturbed current are also presented. This work can serve as an important reference for the experimental design of large volume helicon plasma source with high RF power.

Mixing model with multi-particle interactions for Lagrangian simulations of turbulent mixing

NASA Astrophysics Data System (ADS)

Watanabe, T.; Nagata, K.

2016-08-01

We report on the numerical study of the mixing volume model (MVM) for molecular diffusion in Lagrangian simulations of turbulent mixing problems. The MVM is based on the multi-particle interaction in a finite volume (mixing volume). A priori test of the MVM, based on the direct numerical simulations of planar jets, is conducted in the turbulent region and the interfacial layer between the turbulent and non-turbulent fluids. The results show that the MVM predicts well the mean effects of the molecular diffusion under various numerical and flow parameters. The number of the mixing particles should be large for predicting a value of the molecular diffusion term positively correlated to the exact value. The size of the mixing volume relative to the Kolmogorov scale η is important in the performance of the MVM. The scalar transfer across the turbulent/non-turbulent interface is well captured by the MVM especially with the small mixing volume. Furthermore, the MVM with multiple mixing particles is tested in the hybrid implicit large-eddy-simulation/Lagrangian-particle-simulation (LES-LPS) of the planar jet with the characteristic length of the mixing volume of O(100η). Despite the large mixing volume, the MVM works well and decays the scalar variance in a rate close to the reference LES. The statistics in the LPS are very robust to the number of the particles used in the simulations and the computational grid size of the LES. Both in the turbulent core region and the intermittent region, the LPS predicts a scalar field well correlated to the LES.

Mixing model with multi-particle interactions for Lagrangian simulations of turbulent mixing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Watanabe, T., E-mail: watanabe.tomoaki@c.nagoya-u.jp; Nagata, K.

We report on the numerical study of the mixing volume model (MVM) for molecular diffusion in Lagrangian simulations of turbulent mixing problems. The MVM is based on the multi-particle interaction in a finite volume (mixing volume). A priori test of the MVM, based on the direct numerical simulations of planar jets, is conducted in the turbulent region and the interfacial layer between the turbulent and non-turbulent fluids. The results show that the MVM predicts well the mean effects of the molecular diffusion under various numerical and flow parameters. The number of the mixing particles should be large for predicting amore » value of the molecular diffusion term positively correlated to the exact value. The size of the mixing volume relative to the Kolmogorov scale η is important in the performance of the MVM. The scalar transfer across the turbulent/non-turbulent interface is well captured by the MVM especially with the small mixing volume. Furthermore, the MVM with multiple mixing particles is tested in the hybrid implicit large-eddy-simulation/Lagrangian-particle-simulation (LES–LPS) of the planar jet with the characteristic length of the mixing volume of O(100η). Despite the large mixing volume, the MVM works well and decays the scalar variance in a rate close to the reference LES. The statistics in the LPS are very robust to the number of the particles used in the simulations and the computational grid size of the LES. Both in the turbulent core region and the intermittent region, the LPS predicts a scalar field well correlated to the LES.« less

Proceedings of the International Conference on the Psychology of Mathematics Education (PME) (11th, Montreal, Canada, July 19-25, 1987). Volumes I-III.

ERIC Educational Resources Information Center

Bergeron, Jacques C., Ed.; And Others

The Proceedings of PME-XI has been published in three separate volumes because of the large total of 161 individual conference papers reported. Volume I contains four plenary papers, all on the subject of "constructivism," and 44 commented papers arranged under 4 themes. Volume II contains 56 papers (39 commented; 17 uncommented)…

Proceedings of the International Conference for the Psychology of Mathematics Education (PME) (18th, Lisbon, Portugal, July 29-August 3, 1994). Volumes I-IV.

ERIC Educational Resources Information Center

da Ponte, Joao Pedro, Ed.; Matos, Joao Filipe, Ed.

The Proceedings of PME-XVIII have been published in four separate volumes because of the large number of individual conference papers reported. Volume I contains brief reports for 11 Working Groups and 8 Discussion Groups, 55 "Short Oral Communications," 28 Posters, 5 Plenary Panel reports, and 4 Plenary Session reports. Volume II…

Technical Note: The determination of enclosed water volume in large flexible-wall mesocosms "KOSMOS"

NASA Astrophysics Data System (ADS)

Czerny, J.; Schulz, K. G.; Krug, S. A.; Ludwig, A.; Riebesell, U.

2013-03-01

The volume of water enclosed inside flexible-wall mesocosm bags is hard to estimate using geometrical calculations and can be strongly variable among bags of the same dimensions. Here we present a method for precise water volume determination in mesocosms using salinity as a tracer. Knowledge of the precise volume of water enclosed allows establishment of exactly planned treatment concentrations and calculation of elemental budgets.

Transform coding for hardware-accelerated volume rendering.

PubMed

Fout, Nathaniel; Ma, Kwan-Liu

2007-01-01

Hardware-accelerated volume rendering using the GPU is now the standard approach for real-time volume rendering, although limited graphics memory can present a problem when rendering large volume data sets. Volumetric compression in which the decompression is coupled to rendering has been shown to be an effective solution to this problem; however, most existing techniques were developed in the context of software volume rendering, and all but the simplest approaches are prohibitive in a real-time hardware-accelerated volume rendering context. In this paper we present a novel block-based transform coding scheme designed specifically with real-time volume rendering in mind, such that the decompression is fast without sacrificing compression quality. This is made possible by consolidating the inverse transform with dequantization in such a way as to allow most of the reprojection to be precomputed. Furthermore, we take advantage of the freedom afforded by off-line compression in order to optimize the encoding as much as possible while hiding this complexity from the decoder. In this context we develop a new block classification scheme which allows us to preserve perceptually important features in the compression. The result of this work is an asymmetric transform coding scheme that allows very large volumes to be compressed and then decompressed in real-time while rendering on the GPU.

The effects of load history and design variables on performance limit states of circular bridge columns - volume 2 : experimental observations.

DOT National Transportation Integrated Search

2015-01-01

This report is the second of three volumes and presents detailed data and test summaries of the experimental portion of the work. In total : 30 large scale reinforced concrete bridge columns are reported in this volume. Recommendations for design and...

Determining volume sensitive waters in Beaufort County, SC tidal creeks

Treesearch

Andrew Tweel; Denise Sanger; Anne Blair; John Leffler

2016-01-01

Non-point source pollution from stormwater runoff associated with large-scale land use changes threatens the integrity of ecologically and economically valuable estuarine ecosystems. Beaufort County, SC implemented volume-based stormwater regulations on the rationale that if volume discharge is controlled, contaminant loading will also be controlled.

Detecting an Extended Light Source through a Lens

ERIC Educational Resources Information Center

Litaker, E. T.; Machacek, J. R.; Gay, T. J.

2011-01-01

We present a Monte Carlo simulation of a cylindrical luminescent volume and a typical lens-detector system. The results of this simulation yield a graphically simple picture of the regions within the cylindrical volume from which this system detects light. Because the cylindrical volume permits large angles of incidence, we use a modification of…

Using Hematology Data from Malaria Vaccine Research Trials in Humans and Rhesus Macaques (Macaca mulatta) To Guide Volume Limits for Blood Withdrawal.

PubMed

Hegge, Sara R; Hickey, Bradley W; Mcgrath, Shannon M; Stewart, V Ann

2016-12-01

Guidelines on safe volume limits for blood collection from research participants in both humans and laboratory animals vary widely between institutions. The main adverse event that may be encountered in large blood volume withdrawal is iron-deficiency anemia. Monitoring various parameters in a standard blood panel may help to prevent this outcome. To this end, we analyzed the Hgb and MCV values from 43 humans and 46 macaques in malaria vaccine research trials. Although the percentage of blood volume removed was greater for macaques than humans, macaques demonstrated an overall increase of MCV over time, indicating the ability to respond appropriately to frequent volume withdrawals. In contrast, humans showed a consistent declining trend in MCV. These declines in human MCV and Hgb were significant from the beginning to end of the study despite withdrawals that were smaller than recommended volume limits. Limiting the volume withdrawn to no more than 12.5% seemed to be sufficient for macaques, and at 14% or more individual animals tended to fail to respond appropriately to large-volume blood loss, as demonstrated by a decrease in MCV. The overall positive erythropoietic response seen in macaques was likely due to the controlled, iron-fortified diet they received. The lack of erythropoietic response in the human subjects may warrant iron supplementation or reconsideration of current blood volume withdrawal guidelines.

Design and Analysis of A Beacon-Less Routing Protocol for Large Volume Content Dissemination in Vehicular Ad Hoc Networks.

PubMed

Hu, Miao; Zhong, Zhangdui; Ni, Minming; Baiocchi, Andrea

2016-11-01

Large volume content dissemination is pursued by the growing number of high quality applications for Vehicular Ad hoc NETworks(VANETs), e.g., the live road surveillance service and the video-based overtaking assistant service. For the highly dynamical vehicular network topology, beacon-less routing protocols have been proven to be efficient in achieving a balance between the system performance and the control overhead. However, to the authors' best knowledge, the routing design for large volume content has not been well considered in the previous work, which will introduce new challenges, e.g., the enhanced connectivity requirement for a radio link. In this paper, a link Lifetime-aware Beacon-less Routing Protocol (LBRP) is designed for large volume content delivery in VANETs. Each vehicle makes the forwarding decision based on the message header information and its current state, including the speed and position information. A semi-Markov process analytical model is proposed to evaluate the expected delay in constructing one routing path for LBRP. Simulations show that the proposed LBRP scheme outperforms the traditional dissemination protocols in providing a low end-to-end delay. The analytical model is shown to exhibit a good match on the delay estimation with Monte Carlo simulations, as well.

Design and Analysis of A Beacon-Less Routing Protocol for Large Volume Content Dissemination in Vehicular Ad Hoc Networks

PubMed Central

Hu, Miao; Zhong, Zhangdui; Ni, Minming; Baiocchi, Andrea

2016-01-01

Large volume content dissemination is pursued by the growing number of high quality applications for Vehicular Ad hoc NETworks(VANETs), e.g., the live road surveillance service and the video-based overtaking assistant service. For the highly dynamical vehicular network topology, beacon-less routing protocols have been proven to be efficient in achieving a balance between the system performance and the control overhead. However, to the authors’ best knowledge, the routing design for large volume content has not been well considered in the previous work, which will introduce new challenges, e.g., the enhanced connectivity requirement for a radio link. In this paper, a link Lifetime-aware Beacon-less Routing Protocol (LBRP) is designed for large volume content delivery in VANETs. Each vehicle makes the forwarding decision based on the message header information and its current state, including the speed and position information. A semi-Markov process analytical model is proposed to evaluate the expected delay in constructing one routing path for LBRP. Simulations show that the proposed LBRP scheme outperforms the traditional dissemination protocols in providing a low end-to-end delay. The analytical model is shown to exhibit a good match on the delay estimation with Monte Carlo simulations, as well. PMID:27809285

High axial resolution imaging system for large volume tissues using combination of inclined selective plane illumination and mechanical sectioning

PubMed Central

Zhang, Qi; Yang, Xiong; Hu, Qinglei; Bai, Ke; Yin, Fangfang; Li, Ning; Gang, Yadong; Wang, Xiaojun; Zeng, Shaoqun

2017-01-01

To resolve fine structures of biological systems like neurons, it is required to realize microscopic imaging with sufficient spatial resolution in three dimensional systems. With regular optical imaging systems, high lateral resolution is accessible while high axial resolution is hard to achieve in a large volume. We introduce an imaging system for high 3D resolution fluorescence imaging of large volume tissues. Selective plane illumination was adopted to provide high axial resolution. A scientific CMOS working in sub-array mode kept the imaging area in the sample surface, which restrained the adverse effect of aberrations caused by inclined illumination. Plastic embedding and precise mechanical sectioning extended the axial range and eliminated distortion during the whole imaging process. The combination of these techniques enabled 3D high resolution imaging of large tissues. Fluorescent bead imaging showed resolutions of 0.59 μm, 0.47μm, and 0.59 μm in the x, y, and z directions, respectively. Data acquired from the volume sample of brain tissue demonstrated the applicability of this imaging system. Imaging of different depths showed uniform performance where details could be recognized in either the near-soma area or terminal area, and fine structures of neurons could be seen in both the xy and xz sections. PMID:29296503

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smeets, Albert J., E-mail: radiol@eztilburg.nl; Nijenhuis, Robbert J.; Rooij, Willem Jan van

Uterine artery embolization (UAE) in patients with a large fibroid burden is controversial. Anecdotal reports describe serious complications and limited clinical results. We report the long-term clinical and magnetic resonance (MR) results in a large series of women with a dominant fibroid of >10 cm and/or an uterine volume of >700 cm{sup 3}. Seventy-one consecutive patients (mean age, 42.5 years; median, 40 years; range, 25-52 years) with a large fibroid burden were treated by UAE between August 2000 and April 2005. Volume reduction and infarction rate of dominant fibroid and uterus were assessed by comparing the baseline and latest follow-upmore » MRIs. Patients were clinically followed at various time intervals after UAE with standardized questionnaires. There were no serious complications of UAE. During a mean follow-up of 48 months (median, 59 months; range, 6-106 months), 10 of 71 patients (14%) had a hysterectomy. Mean volume reduction of the fibroid and uterus was 44 and 43%. Mean infarction rate of the fibroid and overall fibroid infarction rate was 86 and 87%. In the vast majority of patients there was a substantial improvement of symptoms. Clinical results were similar in patients with a dominant fibroid >10 cm and in patients with large uterine volumes by diffuse fibroid disease. In conclusion, our results indicate that the risk of serious complications after UAE in patients with a large fibroid burden is not increased. Moreover, clinical long-term results are as good as in other patients who are treated with UAE. Therefore, a large fibroid burden should not be considered a contraindication for UAE.« less

Mechanism of explosive eruptions of Kilauea Volcano, Hawaii

USGS Publications Warehouse

Dvorak, J.J.

1992-01-01

A small explosive eruption of Kilauea Volcano, Hawaii, occurred in May 1924. The eruption was preceded by rapid draining of a lava lake and transfer of a large volume of magma from the summit reservoir to the east rift zone. This lowered the magma column, which reduced hydrostatic pressure beneath Halemaumau and allowed groundwater to flow rapidly into areas of hot rock, producing a phreatic eruption. A comparison with other events at Kilauea shows that the transfer of a large volume of magma out of the summit reservoir is not sufficient to produce a phreatic eruption. For example, the volume transferred at the beginning of explosive activity in May 1924 was less than the volumes transferred in March 1955 and January-February 1960, when no explosive activity occurred. Likewise, draining of a lava lake and deepening of the floor of Halemaumau, which occurred in May 1922 and August 1923, were not sufficient to produce explosive activity. A phreatic eruption of Kilauea requires both the transfer of a large volume of magma from the summit reservoir and the rapid removal of magma from near the surface, where the surrounding rocks have been heated to a sufficient temperature to produce steam explosions when suddenly contacted by groundwater. ?? 1992 Springer-Verlag.

Solid phase extraction of large volume of water and beverage samples to improve detection limits for GC-MS analysis of bisphenol A and four other bisphenols.

PubMed

Cao, Xu-Liang; Popovic, Svetlana

2018-01-01

Solid phase extraction (SPE) of large volumes of water and beverage products was investigated for the GC-MS analysis of bisphenol A (BPA), bisphenol AF (BPAF), bisphenol F (BPF), bisphenol E (BPE), and bisphenol B (BPB). While absolute recoveries of the method were improved for water and some beverage products (e.g. diet cola, iced tea), breakthrough may also have occurred during SPE of 200 mL of other beverages (e.g. BPF in cola). Improvements in method detection limits were observed with the analysis of large sample volumes for all bisphenols at ppt (pg/g) to sub-ppt levels. This improvement was found to be proportional to sample volumes for water and beverage products with less interferences and noise levels around the analytes. Matrix effects and interferences were observed during SPE of larger volumes (100 and 200 mL) of the beverage products, and affected the accurate analysis of BPF. This improved method was used to analyse bisphenols in various beverage samples, and only BPA was detected, with levels ranging from 0.022 to 0.030 ng/g for products in PET bottles, and 0.085 to 0.32 ng/g for products in cans.

True Volumes of Slope Failure Estimated From a Quaternary Mass-Transport Deposit in the Northern South China Sea

NASA Astrophysics Data System (ADS)

Sun, Qiliang; Alves, Tiago M.; Lu, Xiangyang; Chen, Chuanxu; Xie, Xinong

2018-03-01

Submarine slope failure can mobilize large amounts of seafloor sediment, as shown in varied offshore locations around the world. Submarine landslide volumes are usually estimated by mapping their tops and bases on seismic data. However, two essential components of the total volume of failed sediments are overlooked in most estimates: (a) the volume of subseismic turbidites generated during slope failure and (b) the volume of shear compaction occurring during the emplacement of failed sediment. In this study, the true volume of a large submarine landslide in the northern South China Sea is estimated using seismic, multibeam bathymetry and Ocean Drilling Program/Integrated Ocean Drilling Program well data. The submarine landslide was evacuated on the continental slope and deposited in an ocean basin connected to the slope through a narrow moat. This particular character of the sea floor provides an opportunity to estimate the amount of strata remobilized by slope instability. The imaged volume of the studied landslide is 1035 ± 64 km3, 406 ± 28 km3 on the slope and 629 ± 36 km3 in the ocean basin. The volume of subseismic turbidites is 86 km3 (median value), and the volume of shear compaction is 100 km3, which are 8.6% and 9.7% of the landslide volume imaged on seismic data, respectively. This study highlights that the original volume of the failed sediments is significantly larger than that estimated using seismic and bathymetric data. Volume loss related to the generation of landslide-related turbidites and shear compaction must be considered when estimating the total volume of failed strata in the submarine realm.

Isovolemic hemodilution alters the ratio of whole-body to large-vessel hematocrit (F-cell ratio). A prospective, randomized study comparing the volume effects of hydroxyethyl starch 200,000/0.62 and albumin.

PubMed

Haller, M; Brechtelsbauer, H; Akbulut, C; Fett, W; Briegel, J; Finsterer, U

1995-04-01

To evaluate potential changes in the ratio of whole-body/large-vessel hematocrit (f-cell ratio) during isovolemic hemodilution and to compare the volume effects of 2 different plasma exchange solutions (hydroxyethyl starch 200,000/0.62 6% and human albumin 5%). Prospective, randomized, controlled trial. Operating theater in a university hospital. 24 gynecological patients scheduled for elective surgery. Isovolemic hemodilution was performed using 2 different plasma exchange solutions. Plasma volume was determined using dye dilution technique before and after hemodilution. The volume of withdrawn blood was measured from the change in weight of the blood bags taking into account the specific gravity of blood. The volume of administered plasma exchange solutions exceeded the amount of withdrawn blood by 80 +/- 47 ml (p < 0.001). Plasma volume was 3,067 +/- 327 ml before and 3,517 +/- 458 ml after hemodilution. Using red cell volumes calculated from measured plasma volumes and peripheral hematocrit, a deficit of 249 +/- 133 ml (p < 0.0001) in red cells after hemodilution appeared with the measured withdrawn red cell volumes taken into account. This finding can be explained by a change in the f-cell ratio during isovolemic hemodilution. The volume effect of the exchange solutions was 1.05 for hydroxyethyl starch and 0.95 for albumin. The results demonstrate that a change in the f-cell ratio occurs during isovolemic hemodilution. The estimation of red cell volume or plasma volume changes by using either the hematocrit or plasma or red cell volume determinations together with the hematocrit may lead to erroneous results.

Enhanced FIB-SEM systems for large-volume 3D imaging

PubMed Central

Xu, C Shan; Hayworth, Kenneth J; Lu, Zhiyuan; Grob, Patricia; Hassan, Ahmed M; García-Cerdán, José G; Niyogi, Krishna K; Nogales, Eva; Weinberg, Richard J; Hess, Harald F

2017-01-01

Focused Ion Beam Scanning Electron Microscopy (FIB-SEM) can automatically generate 3D images with superior z-axis resolution, yielding data that needs minimal image registration and related post-processing. Obstacles blocking wider adoption of FIB-SEM include slow imaging speed and lack of long-term system stability, which caps the maximum possible acquisition volume. Here, we present techniques that accelerate image acquisition while greatly improving FIB-SEM reliability, allowing the system to operate for months and generating continuously imaged volumes > 106 µm3. These volumes are large enough for connectomics, where the excellent z resolution can help in tracing of small neuronal processes and accelerate the tedious and time-consuming human proofreading effort. Even higher resolution can be achieved on smaller volumes. We present example data sets from mammalian neural tissue, Drosophila brain, and Chlamydomonas reinhardtii to illustrate the power of this novel high-resolution technique to address questions in both connectomics and cell biology. DOI: http://dx.doi.org/10.7554/eLife.25916.001 PMID:28500755

Optical volume and mass measurements show that mammalian cells swell during mitosis

PubMed Central

Zlotek-Zlotkiewicz, Ewa; Monnier, Sylvain; Cappello, Giovanni; Le Berre, Mael

2015-01-01

The extent, mechanism, and function of cell volume changes during specific cellular events, such as cell migration and cell division, have been poorly studied, mostly because of a lack of adequate techniques. Here we unambiguously report that a large range of mammalian cell types display a significant increase in volume during mitosis (up to 30%). We further show that this increase in volume is tightly linked to the mitotic state of the cell and not to its spread or rounded shape and is independent of the presence of an intact actomyosin cortex. Importantly, this volume increase is not accompanied by an increase in dry mass and thus corresponds to a decrease in cell density. This mitotic swelling might have important consequences for mitotic progression: it might contribute to produce strong pushing forces, allowing mitotic cells to round up; it might also, by lowering cytoplasmic density, contribute to the large change of physicochemical properties observed in mitotic cells. PMID:26598614

Enhanced FIB-SEM systems for large-volume 3D imaging

DOE PAGES

Xu, C. Shan; Hayworth, Kenneth J.; Lu, Zhiyuan; ...

2017-05-13

Focused Ion Beam Scanning Electron Microscopy (FIB-SEM) can automatically generate 3D images with superior z-axis resolution, yielding data that needs minimal image registration and related post-processing. Obstacles blocking wider adoption of FIB-SEM include slow imaging speed and lack of long-term system stability, which caps the maximum possible acquisition volume. Here, we present techniques that accelerate image acquisition while greatly improving FIB-SEM reliability, allowing the system to operate for months and generating continuously imaged volumes > 10 6 ?m 3 . These volumes are large enough for connectomics, where the excellent z resolution can help in tracing of small neuronal processesmore » and accelerate the tedious and time-consuming human proofreading effort. Even higher resolution can be achieved on smaller volumes. We present example data sets from mammalian neural tissue, Drosophila brain, and Chlamydomonas reinhardtii to illustrate the power of this novel high-resolution technique to address questions in both connectomics and cell biology.« less

Parallel Rendering of Large Time-Varying Volume Data

NASA Technical Reports Server (NTRS)

Garbutt, Alexander E.

2005-01-01

Interactive visualization of large time-varying 3D volume datasets has been and still is a great challenge to the modem computational world. It stretches the limits of the memory capacity, the disk space, the network bandwidth and the CPU speed of a conventional computer. In this SURF project, we propose to develop a parallel volume rendering program on SGI's Prism, a cluster computer equipped with state-of-the-art graphic hardware. The proposed program combines both parallel computing and hardware rendering in order to achieve an interactive rendering rate. We use 3D texture mapping and a hardware shader to implement 3D volume rendering on each workstation. We use SGI's VisServer to enable remote rendering using Prism's graphic hardware. And last, we will integrate this new program with ParVox, a parallel distributed visualization system developed at JPL. At the end of the project, we Will demonstrate remote interactive visualization using this new hardware volume renderer on JPL's Prism System using a time-varying dataset from selected JPL applications.

Local fluctuations of the signed traded volumes and the dependencies of demands: a copula analysis

NASA Astrophysics Data System (ADS)

Wang, Shanshan; Guhr, Thomas

2018-03-01

We investigate how the local fluctuations of the signed traded volumes affect the dependence of demands between stocks. We analyze the empirical dependence of demands using copulas and show that they are well described by a bivariate K copula density function. We find that large local fluctuations strongly increase the positive dependence but lower slightly the negative one in the copula density. This interesting feature is due to cross-correlations of volume imbalances between stocks. Also, we explore the asymmetries of tail dependencies of the copula density, which are moderate for the negative dependencies but strong for the positive ones. For the latter, we reveal that large local fluctuations of the signed traded volumes trigger stronger dependencies of demands than of supplies, probably indicating a bull market with persistent raising of prices.

Magma ocean formation due to giant impacts

NASA Technical Reports Server (NTRS)

Tonks, W. B.; Melosh, H. J.

1992-01-01

The effect of giant impacts on the initial chemical and thermal states of the terrestrial planets is just now being explored. A large high speed impact creates an approximately hemispherical melt region with a radius that depends on the projectile's radius and impact speed. It is shown that giant impacts on large planets can create large, intact melt regions containing melt volumes up to a few times the volume of the projectile. These large melt regions are not created on asteroid sized bodies. If extruded to the surface, these regions contain enough melt to create a magma ocean of considerable depth, depending on the impact speed, projectile radius, and gravity of the target planet.

Proceedings of the International Conference on the Psychology of Mathematics Education (PME) (17th, Tsukuba, Japan, July 18-23, 1993). Volumes I-III.

ERIC Educational Resources Information Center

Hirabayashi, Ichiei, Ed.; And Others

The Proceedings of PME-XVII has been published in three volumes because of the large number of papers presented at the conference. Volume I contains a brief Plenary Panel report, 4 full-scale Plenary Addresses, the brief reports of 10 Working Groups and 4 Discussion Groups, and a total of 23 Research Reports grouped under 4 themes. Volume II…

The Consequences of Metric Production for Small Manufacturers. Volume II. Case Studies of Large Business-Small Business Interaction,

DTIC Science & Technology

1982-02-08

II 00 CASE STUDIES OF LARGE BUSINESS - SMALL BUSINESS INTERACTION ’C- DTIC. Henry H1. Hitchcock dlELECTE7 Joseph F. Coates Marcy M. Canavan AUGG261982...J wis&omWWS1ARET N W WASIINGTOW. OC NO$I THE CONSEQUENCES OF METRIC PRODUCTION FOR SMALL MANUFACTURERS Volume 11 CASE STUDIES OF LARGE BUSINESS ... SMALL BUSINESS INTERACTION Accesqi~r, For NTIS GRA&t DTIC TAB Unannoun~ced J’htiI’ctof _ Henry H. Hitchcock vi 1ribr i t o aes Joseph F. Coates Avail arid

Anisotropic evolution of 5D Friedmann-Robertson-Walker spacetime

DOE Office of Scientific and Technical Information (OSTI.GOV)

Middleton, Chad A.; Stanley, Ethan

2011-10-15

We examine the time evolution of the five-dimensional Einstein field equations subjected to a flat, anisotropic Robertson-Walker metric, where the 3D and higher-dimensional scale factors are allowed to dynamically evolve at different rates. By adopting equations of state relating the 3D and higher-dimensional pressures to the density, we obtain an exact expression relating the higher-dimensional scale factor to a function of the 3D scale factor. This relation allows us to write the Friedmann-Robertson-Walker field equations exclusively in terms of the 3D scale factor, thus yielding a set of 4D effective Friedmann-Robertson-Walker field equations. We examine the effective field equations inmore » the general case and obtain an exact expression relating a function of the 3D scale factor to the time. This expression involves a hypergeometric function and cannot, in general, be inverted to yield an analytical expression for the 3D scale factor as a function of time. When the hypergeometric function is expanded for small and large arguments, we obtain a generalized treatment of the dynamical compactification scenario of Mohammedi [Phys. Rev. D 65, 104018 (2002)] and the 5D vacuum solution of Chodos and Detweiler [Phys. Rev. D 21, 2167 (1980)], respectively. By expanding the hypergeometric function near a branch point, we obtain the perturbative solution for the 3D scale factor in the small time regime. This solution exhibits accelerated expansion, which, remarkably, is independent of the value of the 4D equation of state parameter w. This early-time epoch of accelerated expansion arises naturally out of the anisotropic evolution of 5D spacetime when the pressure in the extra dimension is negative and offers a possible alternative to scalar field inflationary theory.« less

Quantum gravity inde Sitter space and anti-de Sitter space

NASA Astrophysics Data System (ADS)

Lippert, Matthew S.

In this thesis, we consider two aspects of quantum gravity---the nature of holography in anti-de Sitter space and string theory models of de Sitter space. Searching for a holographic resolution of the black hole information paradox, we pursue the identity of precursors in the context of AdS/CFT. We consider precursors that encode bulk information causally disconnected from the boundary and whose measurement involves nonlocal bulk processes. Previous arguments that these precursors are large, undecorated Wilson loops are found to be flawed. We construct a toy model of holography which encapsulates the expected properties of precursors and compare it with previous such discussions. The information contained in precursors is argued to be encoded in the high-energy sector of the theory and not observable by low-energy measurements. These considerations lead us to propose a locality bound, which indicates where locality breaks down due to black hole or stringy effects. We apply the locality bound to Hawking's argument for information loss in black hole evaporation. We argue that independence of internal and external Hilbert spaces cannot be established without incorporating strong gravitational effects that undermine locality and invalidate the use of quantum field theory in a semiclassical background geometry. We then turn to the investigation of the landscape of string theory vacua, and investigate a recently constructed de Sitter compactification of IIB string theory, which was shown to be metastable in agreement with general arguments about de Sitter spacetimes in quantum gravity. We describe how discrete flux choices lead to a closely-spaced set of vacua and explore various decay channels. We find that in many situations NS5-brane meditated decays which exchange NSNS 3-form flux for D3-branes are comparatively extremely fast.

Diving in Head First: Finding the Volume of Norris lake

ERIC Educational Resources Information Center

Foster, Drew W.

2008-01-01

This article allows students to apply their knowledge and experience of area and volume to find the volume of Norris Lake, a large reservoir lake in Tennessee. Students have the opportunity to demonstrate their skills in using maps and scales as well as to incorporate the use of technology in developing the solution. This project satisfied the…

Manufacture and Testing of an Activation Foil Package for Use in AFIDS

DTIC Science & Technology

2005-03-01

Miller. Nuclides and Isotopes , 16th ed. Lockheed Martin, 2002. 4. Broadhead, Bryan. Sr. Development Staff, Reactor and Fuel Cycle Analysis ...alternative, the concept of using liquid nitrous oxide inside a reactor to simulate large volumes of air was investigated. Simulation using the...weapon. We analyzed whether N2O could replicate large volumes of air in neutron transport experiments since one cubic centimeter of liquid N2O

Combining universal and odd RR axions for aligned natural inflation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gao, Xin; Li, Tianjun; Shukla, Pramod, E-mail: xingao@vt.edu, E-mail: tli@itp.ac.cn, E-mail: pkshukla@to.infn.it

2014-10-01

We successfully embed the Kim-Nilles-Peloso (KNP) alignment mechanism for enhancing the axion decay constant in the context of large volume type IIB orientifolds. The flat direction is generated in the plane of (C{sub 0}-C{sub 2}) axions corresponding to the involutively even universal axion C{sub 0} and odd axion C{sub 2}, respectively. The moduli stabilization with large volume scheme has been established as well.

Speed-up of the volumetric method of moments for the approximate RCS of large arbitrary-shaped dielectric targets

NASA Astrophysics Data System (ADS)

Moreno, Javier; Somolinos, Álvaro; Romero, Gustavo; González, Iván; Cátedra, Felipe

2017-08-01

A method for the rigorous computation of the electromagnetic scattering of large dielectric volumes is presented. One goal is to simplify the analysis of large dielectric targets with translational symmetries taken advantage of their Toeplitz symmetry. Then, the matrix-fill stage of the Method of Moments is efficiently obtained because the number of coupling terms to compute is reduced. The Multilevel Fast Multipole Method is applied to solve the problem. Structured meshes are obtained efficiently to approximate the dielectric volumes. The regular mesh grid is achieved by using parallelepipeds whose centres have been identified as internal to the target. The ray casting algorithm is used to classify the parallelepiped centres. It may become a bottleneck when too many points are evaluated in volumes defined by parametric surfaces, so a hierarchical algorithm is proposed to minimize the number of evaluations. Measurements and analytical results are included for validation purposes.

A replacement for islet equivalents with improved reliability and validity.

PubMed

Huang, Han-Hung; Ramachandran, Karthik; Stehno-Bittel, Lisa

2013-10-01

Islet equivalent (IE), the standard estimate of isolated islet volume, is an essential measure to determine the amount of transplanted islet tissue in the clinic and is used in research laboratories to normalize results, yet it is based on the false assumption that all islets are spherical. Here, we developed and tested a new easy-to-use method to quantify islet volume with greater accuracy. Isolated rat islets were dissociated into single cells, and the total cell number per islet was determined by using computer-assisted cytometry. Based on the cell number per islet, we created a regression model to convert islet diameter to cell number with a high R2 value (0.8) and good validity and reliability with the same model applicable to young and old rats and males or females. Conventional IE measurements overestimated the tissue volume of islets. To compare results obtained using IE or our new method, we compared Glut2 protein levels determined by Western Blot and proinsulin content via ELISA between small (diameter≤100 μm) and large (diameter≥200 μm) islets. When normalized by IE, large islets showed significantly lower Glut2 level and proinsulin content. However, when normalized by cell number, large and small islets had no difference in Glut2 levels, but large islets contained more proinsulin. In conclusion, normalizing islet volume by IE overestimated the tissue volume, which may lead to erroneous results. Normalizing by cell number is a more accurate method to quantify tissue amounts used in islet transplantation and research.

Large-scale tomographic particle image velocimetry using helium-filled soap bubbles

NASA Astrophysics Data System (ADS)

Kühn, Matthias; Ehrenfried, Klaus; Bosbach, Johannes; Wagner, Claus

2011-04-01

To measure large-scale flow structures in air, a tomographic particle image velocimetry (tomographic PIV) system for measurement volumes of the order of one cubic metre is developed, which employs helium-filled soap bubbles (HFSBs) as tracer particles. The technique has several specific characteristics compared to most conventional tomographic PIV systems, which are usually applied to small measurement volumes. One of them is spot lights on the HFSB tracers, which slightly change their position, when the direction of observation is altered. Further issues are the large particle to voxel ratio and the short focal length of the used camera lenses, which result in a noticeable variation of the magnification factor in volume depth direction. Taking the specific characteristics of the HFSBs into account, the feasibility of our large-scale tomographic PIV system is demonstrated by showing that the calibration errors can be reduced down to 0.1 pixels as required. Further, an accurate and fast implementation of the multiplicative algebraic reconstruction technique, which calculates the weighting coefficients when needed instead of storing them, is discussed. The tomographic PIV system is applied to measure forced convection in a convection cell at a Reynolds number of 530 based on the inlet channel height and the mean inlet velocity. The size of the measurement volume and the interrogation volumes amount to 750 mm × 450 mm × 165 mm and 48 mm × 48 mm × 24 mm, respectively. Validation of the tomographic PIV technique employing HFSBs is further provided by comparing profiles of the mean velocity and of the root mean square velocity fluctuations to respective planar PIV data.

Chemical sensing flow probe

DOEpatents

Laguna, George R.; Peter, Frank J.; Butler, Michael A.

1999-01-01

A new chemical probe determines the properties of an analyte using the light absorption of the products of a reagent/analyte reaction. The probe places a small reaction volume in contact with a large analyte volume. Analyte diffuses into the reaction volume. Reagent is selectively supplied to the reaction volume. The light absorption of the reaction in the reaction volume indicates properties of the original analyte. The probe is suitable for repeated use in remote or hostile environments. It does not require physical sampling of the analyte or result in significant regent contamination of the analyte reservoir.

Chemical sensing flow probe

DOEpatents

Laguna, G.R.; Peter, F.J.; Butler, M.A.

1999-02-16

A new chemical probe determines the properties of an analyte using the light absorption of the products of a reagent/analyte reaction. The probe places a small reaction volume in contact with a large analyte volume. Analyte diffuses into the reaction volume. Reagent is selectively supplied to the reaction volume. The light absorption of the reaction in the reaction volume indicates properties of the original analyte. The probe is suitable for repeated use in remote or hostile environments. It does not require physical sampling of the analyte or result in significant regent contamination of the analyte reservoir. 7 figs.

Relationship of pericardial fat with lipoprotein distribution: The Multi-Ethnic study of atherosclerosis.

PubMed

Ong, Kwok-Leung; Ding, Jingzhong; McClelland, Robyn L; Cheung, Bernard M Y; Criqui, Michael H; Barter, Philip J; Rye, Kerry-Anne; Allison, Matthew A

2015-08-01

Pericardial fat and lipoprotein abnormalities contribute to increased risk of cardiovascular disease (CVD). We investigated the relationship between pericardial fat volume and lipoprotein distribution, and whether the association of pericardial fat volume with subclinical atherosclerosis and incident CVD events differs according to lipoprotein distribution. We analyzed data from 5407 participants from the Multi-Ethnic Study of Atherosclerosis who had measurements of pericardial fat volume, lipoprotein distribution, carotid intima-media thickness (IMT), and coronary artery calcium (CAC). All participants were free of clinically apparent CVD at baseline. Incident CVD was defined as any adjudicated CVD event. After adjusting for demographic factors, traditional risk factors, and biomarkers of inflammation and hemostasis, a larger pericardial fat volume was associated with higher large VLDL particle (VLDL-P) concentration and small HDL particle (HDL-P) concentration, and smaller HDL-P size (regression coefficients = 0.585 nmol/L, 0.366 μmol/L, and -0.025 nm per SD increase in pericardial fat volume respectively, all P < 0.05). The association of pericardial fat volume with large VLDL-P concentration and HDL-P size, but not small HDL-P concentration, remained significant after further adjusting for each other as well as LDL cholesterol, HDL cholesterol, and triglycerides. The relationship of pericardial fat volume with incident CVD events, carotid IMT, and prevalence and severity of CAC did not differ by quartiles of large VLDL-P concentration, small HDL-P concentration, or HDL-P size (P for interaction>0.05). Pericardial fat is associated with atherogenic lipoprotein abnormalities. However, its relationship with subclinical atherosclerosis and incident CVD events does not differ according to lipoprotein distribution. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Precipitation, landsliding, and erosion across the Olympic Mountains, Washington State, USA

NASA Astrophysics Data System (ADS)

Smith, Stephen G.; Wegmann, Karl W.

2018-01-01

In the Olympic Mountains of Washington State, landsliding is the primary surface process by which bedrock and hillslope regolith are delivered to river networks. However, the relative importance of large earthquakes versus high magnitude precipitation events to the total volume of landslide material transported to valley bottoms remains unknown in part due to the absence of large historical earthquakes. To test the hypothesis that erosion is linked to precipitation, approximately 1000 landslides were mapped from Google Earth imagery between 1990 and 2015 along a 15 km-wide × 85 km-long (1250 km2) swath across the range. The volume of hillslope material moved by each slide was calculated using previously published area-volume scaling relationships, and the spatial distribution of landslide volume was compared to mean annual precipitation data acquired from the PRISM climate group for the period 1981-2010. Statistical analysis reveals a significant correlation (r = 0.55; p < 0.001) between total landslide volume and mean annual precipitation, with 98% of landslide volume occurring along the windward, high-precipitation side of the range during the 25-year interval. Normalized to area, this volume yields a basin-wide erosion rate of 0.28 ± 0.11 mm yr- 1, which is similar to previous time-variable estimates of erosion throughout the Olympic Mountains, including those from river sediment yield, cosmogenic 10Be, fluvial terrace incision, and thermochronometry. The lack of large historic earthquakes makes it difficult to assess the relative contributions of precipitation and seismic shaking to total erosion, but our results suggest that climate, and more specifically a sharp precipitation gradient, plays an important role in controlling erosion and landscape evolution over both short and long timescales across the Olympic Mountains.

Relationship between pineal cyst size and aqueductal CSF flow measured by phase contrast MRI.

PubMed

Bezuidenhout, Abraham F; Kasper, Ekkehard M; Baledent, Olivier; Rojas, Rafael; Bhadelia, Rafeeque A

2018-02-23

Most patients with pineal cysts referred for neurosurgical consultation have no specific symptoms or objective findings except for pineal cyst size to help in management decisions. Our purpose was to assess the relationship between pineal cyst size and aqueductal CSF flow using PC-MRI. Eleven adult patients with pineal cysts (> 1-cm in size) referred for neurosurgical consultations were included. Cyst volume was calculated using 3D T1 images. PC-MRI in axial plane with velocity encoding of 5 cm/sec was used to quantitatively assess CSF flow through the cerebral aqueduct to determine the aqueductal stroke volume, which was then correlated to cyst size using Pearson's correlation. Pineal cysts were grouped by size into small (6/11) and large (5/11) using the median value to compare aqueductal stroke volume using Mann-Whitney test. Patients were 39 ± 13 years (mean ± SD) of age, and 10/11 (91%) were female. There was significant negative correlation between cyst volume and aqueductal stroke volume (r=0.74; p=0.009). Volume of small cysts (4954±2157 mm3) was significantly different compared to large cysts (13752±3738 mm3; p= 0.008). The aqueductal stroke volume of patients harboring large cysts 33±8 μL/cardiac cycle was significantly lower than that of patients with small cysts 96±29 μL/cardiac cycle (p=0.008). Aqueductal CSF flow appears to decrease with increasing pineal cyst size. Our preliminary results provide first evidence that even in the absence of objective neurological findings or hydrocephalus; larger pineal cysts already display decreased CSF flow through the cerebral aqueduct.

TomoEED: Fast Edge-Enhancing Denoising of Tomographic Volumes.

PubMed

Moreno, J J; Martínez-Sánchez, A; Martínez, J A; Garzón, E M; Fernández, J J

2018-05-29

TomoEED is an optimized software tool for fast feature-preserving noise filtering of large 3D tomographic volumes on CPUs and GPUs. The tool is based on the anisotropic nonlinear diffusion method. It has been developed with special emphasis in the reduction of the computational demands by using different strategies, from the algorithmic to the high performance computing perspectives. TomoEED manages to filter large volumes in a matter of minutes in standard computers. TomoEED has been developed in C. It is available for Linux platforms at http://www.cnb.csic.es/%7ejjfernandez/tomoeed. gmartin@ual.es, JJ.Fernandez@csic.es. Supplementary data are available at Bioinformatics online.

Evaluation of possibility to increasing sustainability of high-rise buildings through use university intellectual property

NASA Astrophysics Data System (ADS)

Potekhin, Igor; Mischenko, Valeryi; Mottaeva, Angela; Zheltenkov, Alexander

2018-03-01

In this article explained approach of valuation of intellectual property of Voronezh State Technical University, as her usefulness to increasing the sustainability and ecological safety of high-rise building. High-rise building is main type of buildings in modern cities. They include large volume of material mass, high volume of energy using and high volume of emissions. Using innovation solutions to improving ecology safety of high-rise buildings has large potential to city in whole. Explained in the article methods of calculation of effects helps to value sustainable solutions of present and future generations. Thus usefulness of patents express through usefulness regarding to high-rise building, including for sustainable development.

Choice of the replacement fluid during large volume plasma-exchange.

PubMed

Nydegger, U E

1983-01-01

The replacement fluid used during therapeutic large volume plasma-exchange can be seen as an important factor influencing the result of such treatment. The choice includes fluids such as electrolyte solutions, gelatin, hydroxyethyl-starch, albumin and fresh frozen plasma. By evaluating the pathophysiology of the underlying disease, it is possible to choose between merely replacing the removed volume by non-protein fluids or rather to introduce plasma protein components into the patient's circulation by substituting with purified or enriched proteins such as albumin, clotting factors, antithrombin III or fresh frozen plasma. This paper analyzes the rationale for the choice of the appropriate replacement fluid taking into account pathophysiologic, pharmacologic and logistic criteria.

Strategies for Analyzing Sub-Micrometer Features with the FE-EPMA

NASA Astrophysics Data System (ADS)

McSwiggen, P.; Armstrong, J. T.; Nielsen, C.

2013-12-01

Changes in column design and electronics, as well as new types of spectrometers and analyzing crystals, have significantly advanced electron microprobes, in terms of stability, reproducibility and detection limits. A major advance in spatial resolution has occurred through the use of the field emission electron gun. The spatial resolution of an analysis is controlled by the diameter of the electron beam and the amount of scatter that takes place within the sample. The beam diameter is controlled by the column and type of electron gun being used. The accelerating voltage and the average atomic number/density of the sample control the amount of electron scatter within the sample. However a large electron interaction volume does not necessarily mean a large analytical volume. The beam electrons may spread out within a large volume, but if the electrons lack sufficient energy to produce the X-ray of interest, the analytical volume could be significantly smaller. Therefore there are two competing strategies for creating the smallest analytical volumes. The first strategy is to reduce the accelerating voltage to produce the smallest electron interaction volume. This low kV analytical approach is ultimately limited by the size of the electron beam itself. With a field emission gun, normally the smallest analytical area is achieved at around 5-7 kV. At lower accelerating voltages, the increase in the beam diameter begins to overshadow the reduction in internal scattering. For tungsten filament guns, the smallest analytical volume is reached at higher accelerating voltages. The second strategy is to minimize the overvoltage during the analysis. If the accelerating voltage is only 1-3 kV greater than the critical ionization energy for the X-ray line of interest, then even if the overall electron interaction volume is large, those electrons quickly loose sufficient energy to produce the desired X-rays. The portion of the interaction volume in which the desired X-rays will be produce will be very small and very near the surface. Both strategies have advantages and disadvantages depending on the ultimate goal of the analysis and the elements involved. This work will examine a number of considerations when attempting to decide which approach is best for a given analytical situation. These include: (1) the size of the analytical volumes, (2) minimum detection limits, (3) quality of the matrix corrections, (4) secondary fluorescence, (5) effects of surface contamination, oxide layers, and carbon coatings. This work is based on results largely from the Fe-Ni binary. A simple conclusion cannot be draw as to which strategy is better overall. The determination is highly system dependent. For many mineral systems, both strategies used in combination will produce the best results. Using multiple accelerating voltages to preform a single analysis allows the analyst to optimize their analytical conditions for each element individually.

A Parallel Pipelined Renderer for the Time-Varying Volume Data

NASA Technical Reports Server (NTRS)

Chiueh, Tzi-Cker; Ma, Kwan-Liu

1997-01-01

This paper presents a strategy for efficiently rendering time-varying volume data sets on a distributed-memory parallel computer. Time-varying volume data take large storage space and visualizing them requires reading large files continuously or periodically throughout the course of the visualization process. Instead of using all the processors to collectively render one volume at a time, a pipelined rendering process is formed by partitioning processors into groups to render multiple volumes concurrently. In this way, the overall rendering time may be greatly reduced because the pipelined rendering tasks are overlapped with the I/O required to load each volume into a group of processors; moreover, parallelization overhead may be reduced as a result of partitioning the processors. We modify an existing parallel volume renderer to exploit various levels of rendering parallelism and to study how the partitioning of processors may lead to optimal rendering performance. Two factors which are important to the overall execution time are re-source utilization efficiency and pipeline startup latency. The optimal partitioning configuration is the one that balances these two factors. Tests on Intel Paragon computers show that in general optimal partitionings do exist for a given rendering task and result in 40-50% saving in overall rendering time.

High correlations between MRI brain volume measurements based on NeuroQuant® and FreeSurfer.

PubMed

Ross, David E; Ochs, Alfred L; Tate, David F; Tokac, Umit; Seabaugh, John; Abildskov, Tracy J; Bigler, Erin D

2018-05-30

NeuroQuant ® (NQ) and FreeSurfer (FS) are commonly used computer-automated programs for measuring MRI brain volume. Previously they were reported to have high intermethod reliabilities but often large intermethod effect size differences. We hypothesized that linear transformations could be used to reduce the large effect sizes. This study was an extension of our previously reported study. We performed NQ and FS brain volume measurements on 60 subjects (including normal controls, patients with traumatic brain injury, and patients with Alzheimer's disease). We used two statistical approaches in parallel to develop methods for transforming FS volumes into NQ volumes: traditional linear regression, and Bayesian linear regression. For both methods, we used regression analyses to develop linear transformations of the FS volumes to make them more similar to the NQ volumes. The FS-to-NQ transformations based on traditional linear regression resulted in effect sizes which were small to moderate. The transformations based on Bayesian linear regression resulted in all effect sizes being trivially small. To our knowledge, this is the first report describing a method for transforming FS to NQ data so as to achieve high reliability and low effect size differences. Machine learning methods like Bayesian regression may be more useful than traditional methods. Copyright © 2018 Elsevier B.V. All rights reserved.

Large space systems technology, 1980, volume 1

NASA Technical Reports Server (NTRS)

Kopriver, F., III (Compiler)

1981-01-01

The technological and developmental efforts in support of the large space systems technology are described. Three major areas of interests are emphasized: (1) technology pertient to large antenna systems; (2) technology related to large space systems; and (3) activities that support both antenna and platform systems.

Wayside Energy Storage Study : Volume 1. Summary.

DOT National Transportation Integrated Search

1979-02-01

Volume I summarizes an in-depth application study which was conducted to determine the practicality and viability of using large wayside flywheels to recuperate braking energy from freight trains on long downgrades. The study examined the route struc...

A Novel Technique for Endovascular Removal of Large Volume Right Atrial Tumor Thrombus

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nickel, Barbara, E-mail: nickel.ba@gmail.com; McClure, Timothy, E-mail: tmcclure@gmail.com; Moriarty, John, E-mail: jmoriarty@mednet.ucla.edu

Venous thromboembolic disease is a significant cause of morbidity and mortality, particularly in the setting of large volume pulmonary embolism. Thrombolytic therapy has been shown to be a successful treatment modality; however, its use somewhat limited due to the risk of hemorrhage and potential for distal embolization in the setting of large mobile thrombi. In patients where either thrombolysis is contraindicated or unsuccessful, and conventional therapies prove inadequate, surgical thrombectomy may be considered. We present a case of percutaneous endovascular extraction of a large mobile mass extending from the inferior vena cava into the right atrium using the Angiovac device,more » a venovenous bypass system designed for high-volume aspiration of undesired endovascular material. Standard endovascular methods for removal of cancer-associated thrombus, such as catheter-directed lysis, maceration, and exclusion, may prove inadequate in the setting of underlying tumor thrombus. Where conventional endovascular methods either fail or are unsuitable, endovascular thrombectomy with the Angiovac device may be a useful and safe minimally invasive alternative to open resection.« less

Determination of dissolved-phase pesticides in surface water from the Yakima River basin, Washington, using the Goulden large-sample extractor and gas chromatography/mass spectrometer

USGS Publications Warehouse

Foster, Gregory D.; Gates, Paul M.; Foreman, William T.; McKenzie, Stuart W.; Rinella, Frank A.

1993-01-01

Concentrations of pesticides in the dissolved phase of surface water samples from the Yakima River basin, WA, were determined using preconcentration in the Goulden large-sample extractor (GLSE) and gas chromatography/mass spectrometry (GC/MS) analysis. Sample volumes ranging from 10 to 120 L were processed with the GLSE, and the results from the large-sample analyses were compared to those derived from 1-L continuous liquid-liquid extractions Few of the 40 target pesticides were detected in 1-L samples, whereas large-sample preconcentration in the GLSE provided detectable levels for many of the target pesticides. The number of pesticides detected in GLSE processed samples was usually directly proportional to sample volume, although the measured concentrations of the pesticides were generally lower at the larger sample volumes for the same water source. The GLSE can be used to provide lower detection levels relative to conventional liquid-liquid extraction in GC/MS analysis of pesticides in samples of surface water.

Avian paternal care had dinosaur origin.

PubMed

Varricchio, David J; Moore, Jason R; Erickson, Gregory M; Norell, Mark A; Jackson, Frankie D; Borkowski, John J

2008-12-19

The repeated discovery of adult dinosaurs in close association with egg clutches leads to speculation over the type and extent of care exhibited by these extinct animals for their eggs and young. To assess parental care in Cretaceous troodontid and oviraptorid dinosaurs, we examined clutch volume and the bone histology of brooding adults. In comparison to four archosaur care regressions, the relatively large clutch volumes of Troodon, Oviraptor, and Citipati scale most closely with a bird-paternal care model. Clutch-associated adults lack the maternal and reproductively associated histologic features common to extant archosaurs. Large clutch volumes and a suite of reproductive features shared only with birds favor paternal care, possibly within a polygamous mating system. Paternal care in both troodontids and oviraptorids indicates that this care system evolved before the emergence of birds and represents birds' ancestral condition. In extant birds and over most adult sizes, paternal and biparental care correspond to the largest and smallest relative clutch volumes, respectively.

Epoxidized Natural Rubber/Chitosan Network Binder for Silicon Anode in Lithium-Ion Battery.

PubMed

Lee, Sang Ha; Lee, Jeong Hun; Nam, Dong Ho; Cho, Misuk; Kim, Jaehoon; Chanthad, Chalathorn; Lee, Youngkwan

2018-05-16

Polymeric binder is extremely important for Si-based anode in lithium-ion batteries due to large volume variation during charging/discharging process. Here, natural rubber-incorporated chitosan networks were designed as a binder material to obtain both adhesion and elasticity. Chitosan could strongly anchor Si particles through hydrogen bonding, while the natural rubber could stretch reversibly during the volume variation of Si particles, resulting in high cyclic performance. The prepared electrode exhibited the specific capacities of 1350 mAh/g after 1600 cycles at the current density of 8 A/g and 2310 mAh/g after 500 cycles at the current density of 1 A/g. Furthermore, the cycle test with limiting lithiation capacity was conducted to study the optimal binder properties at varying degree of the volume expansion of silicon, and it was found that the elastic property of binder material was strongly required when the large volume expansion of Si occurred.

Multi-hadron spectroscopy in a large physical volume

NASA Astrophysics Data System (ADS)

Bulava, John; Hörz, Ben; Morningstar, Colin

2018-03-01

We demonstrate the effcacy of the stochastic LapH method to treat all-toall quark propagation on a Nf = 2 + 1 CLS ensemble with large linear spatial extent L = 5:5 fm, allowing us to obtain the benchmark elastic isovector p-wave pion-pion scattering amplitude to good precision already on a relatively small number of gauge configurations. These results hold promise for multi-hadron spectroscopy at close-to-physical pion mass with exponential finite-volume effects under control.

Development of a Plastic Embedding Method for Large-Volume and Fluorescent-Protein-Expressing Tissues

PubMed Central

Yang, Zhongqin; Hu, Bihe; Zhang, Yuhui; Luo, Qingming; Gong, Hui

2013-01-01

Fluorescent proteins serve as important biomarkers for visualizing both subcellular organelles in living cells and structural and functional details in large-volume tissues or organs. However, current techniques for plastic embedding are limited in their ability to preserve fluorescence while remaining suitable for micro-optical sectioning tomography of large-volume samples. In this study, we quantitatively evaluated the fluorescence preservation and penetration time of several commonly used resins in a Thy1-eYFP-H transgenic whole mouse brain, including glycol methacrylate (GMA), LR White, hydroxypropyl methacrylate (HPMA) and Unicryl. We found that HMPA embedding doubled the eYFP fluorescence intensity but required long durations of incubation for whole brain penetration. GMA, Unicryl and LR White each penetrated the brain rapidly but also led to variable quenching of eYFP fluorescence. Among the fast-penetrating resins, GMA preserved fluorescence better than LR White and Unicryl. We found that we could optimize the GMA formulation by reducing the polymerization temperature, removing 4-methoxyphenol and adjusting the pH of the resin solution to be alkaline. By optimizing the GMA formulation, we increased percentage of eYFP fluorescence preservation in GMA-embedded brains nearly two-fold. These results suggest that modified GMA is suitable for embedding large-volume tissues such as whole mouse brain and provide a novel approach for visualizing brain-wide networks. PMID:23577174

Three-Dimensional Cell Printing of Large-Volume Tissues: Application to Ear Regeneration.

PubMed

Lee, Jung-Seob; Kim, Byoung Soo; Seo, Donghwan; Park, Jeong Hun; Cho, Dong-Woo

2017-03-01

The three-dimensional (3D) printing of large-volume cells, printed in a clinically relevant size, is one of the most important challenges in the field of tissue engineering. However, few studies have reported the fabrication of large-volume cell-printed constructs (LCCs). To create LCCs, appropriate fabrication conditions should be established: Factors involved include fabrication time, residence time, and temperature control of the cell-laden hydrogel in the syringe to ensure high cell viability and functionality. The prolonged time required for 3D printing of LCCs can reduce cell viability and result in insufficient functionality of the construct, because the cells are exposed to a harsh environment during the printing process. In this regard, we present an advanced 3D cell-printing system composed of a clean air workstation, a humidifier, and a Peltier system, which provides a suitable printing environment for the production of LCCs with high cell viability. We confirmed that the advanced 3D cell-printing system was capable of providing enhanced printability of hydrogels and fabricating an ear-shaped LCC with high cell viability. In vivo results for the ear-shaped LCC also showed that printed chondrocytes proliferated sufficiently and differentiated into cartilage tissue. Thus, we conclude that the advanced 3D cell-printing system is a versatile tool to create cell-printed constructs for the generation of large-volume tissues.

Naked-eye 3D imaging employing a modified MIMO micro-ring conjugate mirrors

NASA Astrophysics Data System (ADS)

Youplao, P.; Pornsuwancharoen, N.; Amiri, I. S.; Thieu, V. N.; Yupapin, P.

2018-03-01

In this work, the use of a micro-conjugate mirror that can produce the 3D image incident probe and display is proposed. By using the proposed system together with the concept of naked-eye 3D imaging, a pixel and a large volume pixel of a 3D image can be created and displayed as naked-eye perception, which is valuable for the large volume naked-eye 3D imaging applications. In operation, a naked-eye 3D image that has a large pixel volume will be constructed by using the MIMO micro-ring conjugate mirror system. Thereafter, these 3D images, formed by the first micro-ring conjugate mirror system, can be transmitted through an optical link to a short distance away and reconstructed via the recovery conjugate mirror at the other end of the transmission. The image transmission is performed by the Fourier integral in MATLAB and compares to the Opti-wave program results. The Fourier convolution is also included for the large volume image transmission. The simulation is used for the manipulation, where the array of a micro-conjugate mirror system is designed and simulated for the MIMO system. The naked-eye 3D imaging is confirmed by the concept of the conjugate mirror in both the input and output images, in terms of the four-wave mixing (FWM), which is discussed and interpreted.

What Would Be the Effect of Referral to High-Volume Hospitals in a Largely Rural State?

ERIC Educational Resources Information Center

Ward, Marcia M.; Jaana, Mirou; Wakefield, Douglas S.; Ohsfeldt, Robert L.; Schneider, John E.; Miller, Thomas; Lei, Yang

2004-01-01

Volume of certain surgical procedures has been linked to patient outcomes. The Leapfrog Group and others have recommended evidence-based referral using specific volume thresholds for nonemergent cases. The literature is limited on the effect of such referral on hospitals, especially in rural areas. To examine the impact of evidence-based referral…

Central hardwood forests: recent trends in a robust resource

Treesearch

T. W. Birch; D. A. Gansner; W. H. McWilliams

1993-01-01

Re-inventories completed for each of four Central Hardwood States (Kentucky, Ohio, Pennsylvania, and West Virginia) show that forest area is increasing and stocking hit new highs; there is 27 percent more growing-stock volume than a decade ago. Large increases in volume have been recorded for all but the smallest diameter classes. Volume in trees 15 inches in diameter...

Focusing analytes from 50 μL into 500 pL: On-chip focusing from large sample volumes using isotachophoresis.

PubMed

van Kooten, Xander F; Truman-Rosentsvit, Marianna; Kaigala, Govind V; Bercovici, Moran

2017-09-05

The use of on-chip isotachophoresis assays for diagnostic applications is often limited by the small volumes of standard microfluidic channels. Overcoming this limitation is particularly important for detection of 'discrete' biological targets (such as bacteria) at low concentrations, where the volume of processed liquid in a standard microchannel might not contain any targets. We present a novel microfluidic chip that enables ITP focusing of target analytes from initial sample volumes of 50 μL into a concentrated zone with a volume of 500 pL, corresponding to a 100,000-fold increase in mean concentration, and a 300,000-fold increase in peak concentration. We present design considerations for limiting sample dispersion in such large-volume focusing (LVF) chips and discuss the trade-off between assay time and Joule heating, which ultimately governs the scalability of LVF designs. Finally, we demonstrate a 100-fold improvement of ITP focusing performance in the LVF chip as compared to conventional microchannels, and apply this enhancement to achieve highly sensitive detection of both molecular targets (DNA, down to 10 fM) and whole bacteria (down to 100 cfu/mL).

Very Large Area/Volume Microwave ECR Plasma and Ion Source

NASA Technical Reports Server (NTRS)

Foster, John E. (Inventor); Patterson, Michael J. (Inventor)

2009-01-01

The present invention is an apparatus and method for producing very large area and large volume plasmas. The invention utilizes electron cyclotron resonances in conjunction with permanent magnets to produce dense, uniform plasmas for long life ion thruster applications or for plasma processing applications such as etching, deposition, ion milling and ion implantation. The large area source is at least five times larger than the 12-inch wafers being processed to date. Its rectangular shape makes it easier to accommodate to materials processing than sources that are circular in shape. The source itself represents the largest ECR ion source built to date. It is electrodeless and does not utilize electromagnets to generate the ECR magnetic circuit, nor does it make use of windows.

High-throughput, automated extraction of DNA and RNA from clinical samples using TruTip technology on common liquid handling robots.

PubMed

Holmberg, Rebecca C; Gindlesperger, Alissa; Stokes, Tinsley; Brady, Dane; Thakore, Nitu; Belgrader, Philip; Cooney, Christopher G; Chandler, Darrell P

2013-06-11

TruTip is a simple nucleic acid extraction technology whereby a porous, monolithic binding matrix is inserted into a pipette tip. The geometry of the monolith can be adapted for specific pipette tips ranging in volume from 1.0 to 5.0 ml. The large porosity of the monolith enables viscous or complex samples to readily pass through it with minimal fluidic backpressure. Bi-directional flow maximizes residence time between the monolith and sample, and enables large sample volumes to be processed within a single TruTip. The fundamental steps, irrespective of sample volume or TruTip geometry, include cell lysis, nucleic acid binding to the inner pores of the TruTip monolith, washing away unbound sample components and lysis buffers, and eluting purified and concentrated nucleic acids into an appropriate buffer. The attributes and adaptability of TruTip are demonstrated in three automated clinical sample processing protocols using an Eppendorf epMotion 5070, Hamilton STAR and STARplus liquid handling robots, including RNA isolation from nasopharyngeal aspirate, genomic DNA isolation from whole blood, and fetal DNA extraction and enrichment from large volumes of maternal plasma (respectively).

High sulfur loading cathodes fabricated using peapodlike, large pore volume mesoporous carbon for lithium-sulfur battery.

PubMed

Li, Duo; Han, Fei; Wang, Shuai; Cheng, Fei; Sun, Qiang; Li, Wen-Cui

2013-03-01

Porous carbon materials with large pore volume are crucial in loading insulated sulfur with the purpose of achieving high performance for lithium-sulfur batteries. In our study, peapodlike mesoporous carbon with interconnected pore channels and large pore volume (4.69 cm(3) g(-1)) was synthesized and used as the matrix to fabricate carbon/sulfur (C/S) composite which served as attractive cathodes for lithium-sulfur batteries. Systematic investigation of the C/S composite reveals that the carbon matrix can hold a high but suitable sulfur loading of 84 wt %, which is beneficial for improving the bulk density in practical application. Such controllable sulfur-filling also effectively allows the volume expansion of active sulfur during Li(+) insertion. Moreover, the thin carbon walls (3-4 nm) of carbon matrix not only are able to shorten the pathway of Li(+) transfer and conduct electron to overcome the poor kinetics of sulfur cathode, but also are flexible to warrant structure stability. Importantly, the peapodlike carbon shell is beneficial to increase the electrical contact for improving electronic conductivity of active sulfur. Meanwhile, polymer modification with polypyrrole coating layer further restrains polysulfides dissolution and improves the cycle stability of carbon/sulfur composites.

An estimation of vehicle kilometer traveled and on-road emissions using the traffic volume and travel speed on road links in Incheon City.

PubMed

Jung, Sungwoon; Kim, Jounghwa; Kim, Jeongsoo; Hong, Dahee; Park, Dongjoo

2017-04-01

The objective of this study is to estimate the vehicle kilometer traveled (VKT) and on-road emissions using the traffic volume in urban. We estimated two VKT; one is based on registered vehicles and the other is based on traffic volumes. VKT for registered vehicles was 2.11 times greater than that of the applied traffic volumes because each VKT estimation method is different. Therefore, we had to define the inner VKT is moved VKT inner in urban to compare two values. Also, we focused on freight modes because these are discharged much air pollutant emissions. From analysis results, we found middle and large trucks registered in other regions traveled to target city in order to carry freight, target city has included many industrial and logistics areas. Freight is transferred through the harbors, large logistics centers, or via locations before being moved to the final destination. During this process, most freight is moved by middle and large trucks, and trailers rather than small trucks for freight import and export. Therefore, these trucks from other areas are inflow more than registered vehicles. Most emissions from diesel trucks had been overestimated in comparison to VKT from applied traffic volumes in target city. From these findings, VKT is essential based on traffic volume and travel speed on road links in order to estimate accurately the emissions of diesel trucks in target city. Our findings support the estimation of the effect of on-road emissions on urban air quality in Korea. Copyright © 2016. Published by Elsevier B.V.

Binary black hole coalescence in the large-mass-ratio limit: The hyperboloidal layer method and waveforms at null infinity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bernuzzi, Sebastiano; Nagar, Alessandro; Zenginoglu, Anil

2011-10-15

We compute and analyze the gravitational waveform emitted to future null infinity by a system of two black holes in the large-mass-ratio limit. We consider the transition from the quasiadiabatic inspiral to plunge, merger, and ringdown. The relative dynamics is driven by a leading order in the mass ratio, 5PN-resummed, effective-one-body (EOB), analytic-radiation reaction. To compute the waveforms, we solve the Regge-Wheeler-Zerilli equations in the time-domain on a spacelike foliation, which coincides with the standard Schwarzschild foliation in the region including the motion of the small black hole, and is globally hyperboloidal, allowing us to include future null infinity inmore » the computational domain by compactification. This method is called the hyperboloidal layer method, and is discussed here for the first time in a study of the gravitational radiation emitted by black hole binaries. We consider binaries characterized by five mass ratios, {nu}=10{sup -2,-3,-4,-5,-6}, that are primary targets of space-based or third-generation gravitational wave detectors. We show significative phase differences between finite-radius and null-infinity waveforms. We test, in our context, the reliability of the extrapolation procedure routinely applied to numerical relativity waveforms. We present an updated calculation of the final and maximum gravitational recoil imparted to the merger remnant by the gravitational wave emission, v{sub kick}{sup end}/(c{nu}{sup 2})=0.04474{+-}0.00007 and v{sub kick}{sup max}/(c{nu}{sup 2})=0.05248{+-}0.00008. As a self-consistency test of the method, we show an excellent fractional agreement (even during the plunge) between the 5PN EOB-resummed mechanical angular momentum loss and the gravitational wave angular momentum flux computed at null infinity. New results concerning the radiation emitted from unstable circular orbits are also presented. The high accuracy waveforms computed here could be considered for the construction of template banks or for calibrating analytic models such as the effective-one-body model.« less

On gauged maximal d  =  8 supergravities

NASA Astrophysics Data System (ADS)

Lasso Andino, Óscar; Ortín, Tomás

2018-04-01

We study the gauging of maximal d  =  8 supergravity using the embedding tensor formalism. We focus on SO(3) gaugings, study all the possible choices of gauge fields and construct explicitly the bosonic actions (including the complicated Chern–Simons terms) for all these choices, which are parametrized by a parameter associated to the 8-dimensional SL(2, {R}) duality group that relates all the possible choices which are, ultimately, equivalent from the purely 8-dimensional point of view. Our result proves that the theory constructed by Salam and Sezgin by Scherk–Schwarz compactification of d  =  11 supergravity and the theory constructed in Alonso-Alberca (2001 Nucl. Phys. B 602 329) by dimensional reduction of the so called ‘massive 11-dimensional supergravity’ proposed by Meessen and Ortín in (1999 Nucl. Phys. B 541 195) are indeed related by an SL(2, {R}) duality even though they have two completely different 11-dimensional origins.

Negative branes, supergroups and the signature of spacetime

NASA Astrophysics Data System (ADS)

Dijkgraaf, Robbert; Heidenreich, Ben; Jefferson, Patrick; Vafa, Cumrun

2018-02-01

We study the realization of supergroup gauge theories using negative branes in string theory. We show that negative branes are intimately connected with the possibility of timelike compactification and exotic spacetime signatures previously studied by Hull. Isolated negative branes dynamically generate a change in spacetime signature near their worldvolumes, and are related by string dualities to a smooth M-theory geometry with closed timelike curves. Using negative D3-branes, we show that SU(0| N) supergroup theories are holographically dual to an exotic variant of type IIB string theory on {dS}_{3,2}× {\\overline{S}}^5 , for which the emergent dimensions are timelike. Using branes, mirror symmetry and Nekrasov's instanton calculus, all of which agree, we derive the Seiberg-Witten curve for N=2 SU( N | M ) gauge theories. Together with our exploration of holography and string dualities for negative branes, this suggests that supergroup gauge theories may be non-perturbatively well-defined objects, though several puzzles remain.

No-scale SU( 5) super-GUTs

DOE PAGES

Ellis, John; Evans, Jason L.; Nagata, Natsumi; ...

2017-04-12

We reconsider the minimal SU( 5) grand unified theory (GUT) in the context of no-scale supergravity inspired by string compactification scenarios, assuming that the soft supersymmetry-breaking parameters satisfy universality conditions at some input scale M in above the GUT scale M GUT. When setting up such a no-scale super-GUT model, special attention must be paid to avoiding the Scylla of rapid proton decay and the Charybdis of an excessive density of cold dark matter, while also having an acceptable mass for the Higgs boson. Furthermore, we do not find consistent solutions if none of the matter and Higgs fields aremore » assigned to twisted chiral supermultiplets, even in the presence of Giudice–Masiero terms. But, consistent solutions may be found if at least one fiveplet of GUT Higgs fields is assigned to a twisted chiral supermultiplet, with a suitable choice of modular weights. Spin-independent dark matter scattering may be detectable in some of these consistent solutions.« less

Three-dimensional rearrangement of single atoms using actively controlled optical microtraps.

PubMed

Lee, Woojun; Kim, Hyosub; Ahn, Jaewook

2016-05-02

We propose and demonstrate three-dimensional rearrangements of single atoms. In experiments performed with single ⁸⁷Rb atoms in optical microtraps actively controlled by a spatial light modulator, we demonstrate various dynamic rearrangements of up to N = 9 atoms including rotation, 2D vacancy filling, guiding, compactification, and 3D shuffling. With the capability of a phase-only Fourier mask to generate arbitrary shapes of the holographic microtraps, it was possible to place single atoms at arbitrary geometries of a few μm size and even continuously reconfigure them by conveying each atom. For this purpose, we loaded a series of computer-generated phase masks in the full frame rate of 60 Hz of the spatial light modulator, so the animation of phase mask transformed the holographic microtraps in real time, driving each atom along the assigned trajectory. Possible applications of this method of transformation of single atoms include preparation of scalable quantum platforms for quantum computation, quantum simulation, and quantum many-body physics.

BPS algebras, genus zero and the heterotic Monster

NASA Astrophysics Data System (ADS)

Paquette, Natalie M.; Persson, Daniel; Volpato, Roberto

2017-10-01

In this note, we expand on some technical issues raised in (Paquette et al 2016 Commun. Number Theory Phys. 10 433-526) by the authors, as well as providing a friendly introduction to and summary of our previous work. We construct a set of heterotic string compactifications to 0  +  1 dimensions intimately related to the Monstrous moonshine module of Frenkel, Lepowsky, and Meurman (and orbifolds thereof). Using this model, we review our physical interpretation of the genus zero property of Monstrous moonshine. Furthermore, we show that the space of (second-quantized) BPS-states forms a module over the Monstrous Lie algebras mg —some of the first and most prominent examples of Generalized Kac-Moody algebras—constructed by Borcherds and Carnahan. In particular, we clarify the structure of the module present in the second-quantized string theory. We also sketch a proof of our methods in the language of vertex operator algebras, for the interested mathematician.

Algebraic cycles and local anomalies in F-theory

NASA Astrophysics Data System (ADS)

Bies, Martin; Mayrhofer, Christoph; Weigand, Timo

2017-11-01

We introduce a set of identities in the cohomology ring of elliptic fibrations which are equivalent to the cancellation of gauge and mixed gauge-gravitational anomalies in F-theory compactifications to four and six dimensions. The identities consist in (co)homological relations between complex codimension-two cycles. The same set of relations, once evaluated on elliptic Calabi-Yau three-folds and four-folds, is shown to universally govern the structure of anomalies and their Green-Schwarz cancellation in six- and four-dimensional F-theory vacua, respectively. We furthermore conjecture that these relations hold not only within the cohomology ring, but even at the level of the Chow ring, i.e. as relations among codimension-two cycles modulo rational equivalence. We verify this conjecture in non-trivial examples with Abelian and non-Abelian gauge groups factors. Apart from governing the structure of local anomalies, the identities in the Chow ring relate different types of gauge backgrounds on elliptically fibred Calabi-Yau four-folds.

Upper limits to submillimetre-range forces from extra space-time dimensions.

PubMed

Long, Joshua C; Chan, Hilton W; Churnside, Allison B; Gulbis, Eric A; Varney, Michael C M; Price, John C

2003-02-27

String theory is the most promising approach to the long-sought unified description of the four forces of nature and the elementary particles, but direct evidence supporting it is lacking. The theory requires six extra spatial dimensions beyond the three that we observe; it is usually supposed that these extra dimensions are curled up into small spaces. This 'compactification' induces 'moduli' fields, which describe the size and shape of the compact dimensions at each point in space-time. These moduli fields generate forces with strengths comparable to gravity, which according to some recent predictions might be detected on length scales of about 100 microm. Here we report a search for gravitational-strength forces using planar oscillators separated by a gap of 108 micro m. No new forces are observed, ruling out a substantial portion of the previously allowed parameter space for the strange and gluon moduli forces, and setting a new upper limit on the range of the string dilaton and radion forces.

PhD Thesis: String theory in the early universe

NASA Astrophysics Data System (ADS)

Gwyn, Rhiannon

2009-11-01

The intersection of string theory with cosmology is unavoidable in the early universe, and its exploration may shine light on both fields. In this thesis, three papers at this intersection are presented and reviewed, with the aim of providing a thorough and pedagogical guide to their results. First, we address the longstanding problem of finding a string theory realisation of the axion. Using warped compactifications in heterotic string theory, we show that the axion decay constant can be lowered to acceptable values by the warp factor. Next, we move to the subject of cosmic strings, whose network evolution could have important consequences for astrophysics and cosmology. In particular, there are quantitative differences between cosmic superstring networks and GUT cosmic string networks. We investigate the properties of cosmic superstring networks in warped backgrounds, giving the tension and properties of three-string junctions in these backgrounds. Finally, we examine the possibility that cosmic strings in heterotic string theory could be responsible for generating the galactic magnetic fields that seeded those observed today.

AGT relations for abelian quiver gauge theories on ALE spaces

NASA Astrophysics Data System (ADS)

Pedrini, Mattia; Sala, Francesco; Szabo, Richard J.

2016-05-01

We construct level one dominant representations of the affine Kac-Moody algebra gl̂k on the equivariant cohomology groups of moduli spaces of rank one framed sheaves on the orbifold compactification of the minimal resolution Xk of the Ak-1 toric singularity C2 /Zk. We show that the direct sum of the fundamental classes of these moduli spaces is a Whittaker vector for gl̂k, which proves the AGT correspondence for pure N = 2 U(1) gauge theory on Xk. We consider Carlsson-Okounkov type Ext-bundles over products of the moduli spaces and use their Euler classes to define vertex operators. Under the decomposition gl̂k ≃ h ⊕sl̂k, these vertex operators decompose as products of bosonic exponentials associated to the Heisenberg algebra h and primary fields of sl̂k. We use these operators to prove the AGT correspondence for N = 2 superconformal abelian quiver gauge theories on Xk.

Universal consistent truncation for 6d/7d gauge/gravity duals

NASA Astrophysics Data System (ADS)

Passias, Achilleas; Rota, Andrea; Tomasiello, Alessandro

2015-10-01

Recently, AdS7 solutions of IIA supergravity have been classified; there are infinitely many of them, whose expression is known analytically, and with internal space of S 3 topology. Their field theory duals are six-dimensional (1,0) SCFT's. In this paper we show that for each of these AdS7 solutions there exists a consistent truncation from massive IIA supergravity to minimal gauged supergravity in seven dimensions. This theory has an SU(2) gauge group, and a single scalar, whose value is related to a certain distortion of the internal S 3. This explains the universality observed in recent work on AdS5 and AdS4 solutions dual to compactifications of the (1, 0) SCFT6's. Thanks to previous work on the minimal gauged supergravity, the truncation also implies the existence of holographic RG-flows connecting those solutions to the AdS7 vacuum, as well as new classes of IIA AdS3 solutions.

Janus configurations with SL(2, ℤ)-duality twists, strings on mapping tori and a tridiagonal determinant formula

NASA Astrophysics Data System (ADS)

Ganor, Ori J.; Moore, Nathan P.; Sun, Hao-Yu; Torres-Chicon, Nesty R.

2014-07-01

We develop an equivalence between two Hilbert spaces: (i) the space of states of U(1) n Chern-Simons theory with a certain class of tridiagonal matrices of coupling constants (with corners) on T 2; and (ii) the space of ground states of strings on an associated mapping torus with T 2 fiber. The equivalence is deduced by studying the space of ground states of SL(2, ℤ)-twisted circle compactifications of U(1) gauge theory, connected with a Janus configuration, and further compactified on T 2. The equality of dimensions of the two Hilbert spaces (i) and (ii) is equivalent to a known identity on determinants of tridiagonal matrices with corners. The equivalence of operator algebras acting on the two Hilbert spaces follows from a relation between the Smith normal form of the Chern-Simons coupling constant matrix and the isometry group of the mapping torus, as well as the torsion part of its first homology group.

Non-topological cycloops

NASA Astrophysics Data System (ADS)

Lake, Matthew; Thomas, Steven; Ward, John

2010-01-01

We propose a mechanism for the creation of cosmic string loops with dynamically stabilised windings in the internal space. Assuming a velocity correlations regime in the post-inflationary epoch, such windings are seen to arise naturally in string networks prior to loop formation. The angular momentum of the string in the compact space may then be sufficient to ensure that the windings remain stable after the loop chops off from the network, even if the internal manifold is simply connected. For concreteness we embed our model in the Klebanov-Strassler geometry, which provides a natural mechanism for brane inflation, as well a being one of the best understood compactification schemes in type IIB string theory. We see that the interaction of angular momentum with the string tension causes the loop to oscillate between phases of expansion and contraction. This, in principle, should give rise to a distinct gravitational wave signature, the future detection of which could provide indirect evidence for the existence of extra dimensions.

Topological string, supersymmetric gauge theory and bps counting

NASA Astrophysics Data System (ADS)

Pan, Guang

In this thesis we study the Donaldson-Thomas theory on the local curve geometry, which arises in the context of geometric engineering of supersymmetric gauge theory from type IIA string compactification. The topological A-model amplitude gives the F-term interaction of the compactified theory. In particular, it is related to the instanton partition function via Nekrasov conjecture. We will introduce ADHM sheaves on curve, as an alternative description of local Donaldson-Thomas theory. We derive the wallcrossing of ADHM invariants and their refinements. We show that it is equivalent to the semi-primitive wallcrossing from supergravity, and the Kontsevich-Soibelman wallcrossing formula. As an application, we discuss the connection between ADHM moduli space with Hitchin system. In particular we give a recursive formula for the Poincare polynomial of Hitchin system in terms of instanton partition function, from refined wallcrossing. We also introduce higher rank generalization of Donaldson-Thomas invariant in the context of ADHM sheaves. We study their wallcrossing and discuss their physical interpretation via string duality.

All Chern-Simons invariants of 4D, N = 1 gauged superform hierarchies

NASA Astrophysics Data System (ADS)

Becker, Katrin; Becker, Melanie; Linch, William D.; Randall, Stephen; Robbins, Daniel

2017-04-01

We give a geometric description of supersymmetric gravity/(non-)abelian p-form hierarchies in superspaces with 4D, N = 1 super-Poincaré invariance. These hierarchies give rise to Chern-Simons-like invariants, such as those of the 5D, N = 1 graviphoton and the eleven-dimensional 3-form but also generalizations such as Green-Schwarz-like/ BF -type couplings. Previous constructions based on prepotential superfields are reinterpreted in terms of p-forms in superspace thereby elucidating the underlying geometry. This vastly simplifies the calculations of superspace field-strengths, Bianchi identities, and Chern-Simons invariants. Using this, we prove the validity of a recursive formula for the conditions defining these actions for any such tensor hierarchy. Solving it at quadratic and cubic orders, we recover the known results for the BF -type and cubic Chern-Simons actions. As an application, we compute the quartic invariant ˜ AdAdAdA + . . . relevant, for example, to seven-dimensional supergravity compactifications.

Eisenstein Series and String Thresholds

NASA Astrophysics Data System (ADS)

Obers, N. A.; Pioline, B.

We investigate the relevance of Eisenstein series for representing certain G()-invariant string theory amplitudes which receive corrections from BPS states only. G() may stand for any of the mapping class, T-duality and U-duality groups Sl(d,(), SO(d,d,() or Ed+1(d+1)(() respectively. Using G()-invariant mass formulae, we construct invariant modular functions on the symmetric space K\\G() of non-compact type, with K the maximal compact subgroup of G(), that generalize the standard non-holomorphic Eisenstein series arising in harmonic analysis on the fundamental domain of the Poincaré upper half-plane. Comparing the asymptotics and eigenvalues of the Eisenstein series under second order differential operators with quantities arising in one- and g-loop string amplitudes, we obtain a manifestly T-duality invariant representation of the latter, conjecture their non-perturbative U-duality invariant extension, and analyze the resulting non-perturbative effects. This includes the R4 and R4H4g-4 couplings in toroidal compactifications of M-theory to any dimension D>= 4 and D>= 6 respectively.

S-duality in twistor space

NASA Astrophysics Data System (ADS)

Alexandrov, Sergei; Pioline, Boris

2012-08-01

In type IIB string compactifications on a Calabi-Yau threefold, the hypermultiplet moduli space {{M}_H} must carry an isometric action of the modular group SL(2 , {Z} ), inherited from the S-duality symmetry of type IIB string theory in ten dimensions. We investigate how this modular symmetry is realized at the level of the twistor space of {{M}_H} , and construct a general class of SL(2 , {Z} )-invariant quaternion-Kähler metrics with two commuting isometries, parametrized by a suitably covariant family of holomorphic transition functions. This family should include {{M}_H} corrected by D3-D1-D(-1)-instantons (with five-brane corrections ignored) and, after taking a suitable rigid limit, the Coulomb branch of five-dimensional {N} = {2} gauge theories compactified on a torus, including monopole string instantons. These results allow us to considerably simplify the derivation of the mirror map between type IIA and IIB fields in the sector where only D1-D(-1)-instantons are retained.

Lensfree diffractive tomography for the imaging of 3D cell cultures

NASA Astrophysics Data System (ADS)

Berdeu, Anthony; Momey, Fabien; Dinten, Jean-Marc; Gidrol, Xavier; Picollet-D'hahan, Nathalie; Allier, Cédric

2017-02-01

New microscopes are needed to help reaching the full potential of 3D organoid culture studies by gathering large quantitative and systematic data over extended periods of time while preserving the integrity of the living sample. In order to reconstruct large volumes while preserving the ability to catch every single cell, we propose new imaging platforms based on lens-free microscopy, a technic which is addressing these needs in the context of 2D cell culture, providing label-free and non-phototoxic acquisition of large datasets. We built lens-free diffractive tomography setups performing multi-angle acquisitions of 3D organoid cultures embedded in Matrigel and developed dedicated 3D holographic reconstruction algorithms based on the Fourier diffraction theorem. Nonetheless, holographic setups do not record the phase of the incident wave front and the biological samples in Petri dish strongly limit the angular coverage. These limitations introduce numerous artefacts in the sample reconstruction. We developed several methods to overcome them, such as multi-wavelength imaging or iterative phase retrieval. The most promising technic currently developed is based on a regularised inverse problem approach directly applied on the 3D volume to reconstruct. 3D reconstructions were performed on several complex samples such as 3D networks or spheroids embedded in capsules with large reconstructed volumes up to 25 mm3 while still being able to identify single cells. To our knowledge, this is the first time that such an inverse problem approach is implemented in the context of lens-free diffractive tomography enabling to reconstruct large fully 3D volumes of unstained biological samples.

Bridge deck concrete volume change : final contract report.

DOT National Transportation Integrated Search

2010-02-01

Concrete structures such as bridge decks, with large surface area relative to volume, shrink and crack, thus reducing service life performance and increasing operation costs. The project evaluated the early, first 24 hours, and long-term, 180 days, s...

Large-Scale Operations Management Test of Use of the White Amur for Control of Problem Aquatic Plants. Report 3. Second Year Poststocking Results. Volume VI. The Water and Sediment Quality of Lake Conway, Florida.

DTIC Science & Technology

1982-08-01

AD-A-11 701 ORANGE COUNTY POLLUTION CONTROL DEPT ORLANDO FL F/0 6/6 LARGE-SCALE OPERATIONS MANAGEMENT TEST OF USE OF THE WHITE AMUR--ETC(U) AUG 82 H...8217 OPERATIONS MANAGEMENT TEST OF USE OF THE WHITE AMUR FOR CONTROL -OF PROBLEM AQ.UATIC PLANTS SECOND YEAR POSTSTOCKING RESULTS Volume, Vt The Water...and Subetie) S. TYPE OF REPORT & PERIOD COVERED LARGE-SCALE OPERATIONS MANAGEMENT TEST OF USE OF Report 3 of a series THE WHITE AMUR FOR CONTROL OF

Large-volume injection of sample diluents not miscible with the mobile phase as an alternative approach in sample preparation for bioanalysis: an application for fenspiride bioequivalence.

PubMed

Medvedovici, Andrei; Udrescu, Stefan; Albu, Florin; Tache, Florentin; David, Victor

2011-09-01

Liquid-liquid extraction of target compounds from biological matrices followed by the injection of a large volume from the organic layer into the chromatographic column operated under reversed-phase (RP) conditions would successfully combine the selectivity and the straightforward character of the procedure in order to enhance sensitivity, compared with the usual approach of involving solvent evaporation and residue re-dissolution. Large-volume injection of samples in diluents that are not miscible with the mobile phase was recently introduced in chromatographic practice. The risk of random errors produced during the manipulation of samples is also substantially reduced. A bioanalytical method designed for the bioequivalence of fenspiride containing pharmaceutical formulations was based on a sample preparation procedure involving extraction of the target analyte and the internal standard (trimetazidine) from alkalinized plasma samples in 1-octanol. A volume of 75 µl from the octanol layer was directly injected on a Zorbax SB C18 Rapid Resolution, 50 mm length × 4.6 mm internal diameter × 1.8 µm particle size column, with the RP separation being carried out under gradient elution conditions. Detection was made through positive ESI and MS/MS. Aspects related to method development and validation are discussed. The bioanalytical method was successfully applied to assess bioequivalence of a modified release pharmaceutical formulation containing 80 mg fenspiride hydrochloride during two different studies carried out as single-dose administration under fasting and fed conditions (four arms), and multiple doses administration, respectively. The quality attributes assigned to the bioanalytical method, as resulting from its application to the bioequivalence studies, are highlighted and fully demonstrate that sample preparation based on large-volume injection of immiscible diluents has an increased potential for application in bioanalysis.

Challenges in Accommodating Volume Change of Si Anodes for Li-Ion Batteries

PubMed Central

Ko, Minseong; Chae, Sujong; Cho, Jaephil

2015-01-01

Si has been considered as a promising alternative anode for next-generation Li-ion batteries (LIBs) because of its high theoretical energy density, relatively low working potential, and abundance in nature. However, Si anodes exhibit rapid capacity decay and an increase in the internal resistance, which are caused by the large volume changes upon Li insertion and extraction. This unfortunately limits their practical applications. Therefore, managing the total volume change remains a critical challenge for effectively alleviating the mechanical fractures and instability of solid-electrolyte-interphase products. In this regard, we review the recent progress in volume-change-accommodating Si electrodes and investigate their ingenious structures with significant improvements in the battery performance, including size-controlled materials, patterned thin films, porous structures, shape-preserving shell designs, and graphene composites. These representative approaches potentially overcome the large morphologic changes in the volume of Si anodes by securing the strain relaxation and structural integrity in the entire electrode. Finally, we propose perspectives and future challenges to realize the practical application of Si anodes in LIB systems. PMID:27525208

Computer aided detection of ureteral stones in thin slice computed tomography volumes using Convolutional Neural Networks.

PubMed

Längkvist, Martin; Jendeberg, Johan; Thunberg, Per; Loutfi, Amy; Lidén, Mats

2018-06-01

Computed tomography (CT) is the method of choice for diagnosing ureteral stones - kidney stones that obstruct the ureter. The purpose of this study is to develop a computer aided detection (CAD) algorithm for identifying a ureteral stone in thin slice CT volumes. The challenge in CAD for urinary stones lies in the similarity in shape and intensity of stones with non-stone structures and how to efficiently deal with large high-resolution CT volumes. We address these challenges by using a Convolutional Neural Network (CNN) that works directly on the high resolution CT volumes. The method is evaluated on a large data base of 465 clinically acquired high-resolution CT volumes of the urinary tract with labeling of ureteral stones performed by a radiologist. The best model using 2.5D input data and anatomical information achieved a sensitivity of 100% and an average of 2.68 false-positives per patient on a test set of 88 scans. Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.

A panning DLT procedure for three-dimensional videography.

PubMed

Yu, B; Koh, T J; Hay, J G

1993-06-01

The direct linear transformation (DLT) method [Abdel-Aziz and Karara, APS Symposium on Photogrammetry. American Society of Photogrammetry, Falls Church, VA (1971)] is widely used in biomechanics to obtain three-dimensional space coordinates from film and video records. This method has some major shortcomings when used to analyze events which take place over large areas. To overcome these shortcomings, a three-dimensional data collection method based on the DLT method, and making use of panning cameras, was developed. Several small single control volumes were combined to construct a large total control volume. For each single control volume, a regression equation (calibration equation) is developed to express each of the 11 DLT parameters as a function of camera orientation, so that the DLT parameters can then be estimated from arbitrary camera orientations. Once the DLT parameters are known for at least two cameras, and the associated two-dimensional film or video coordinates of the event are obtained, the desired three-dimensional space coordinates can be computed. In a laboratory test, five single control volumes (in a total control volume of 24.40 x 2.44 x 2.44 m3) were used to test the effect of the position of the single control volume on the accuracy of the computed three dimensional space coordinates. Linear and quadratic calibration equations were used to test the effect of the order of the equation on the accuracy of the computed three dimensional space coordinates. For four of the five single control volumes tested, the mean resultant errors associated with the use of the linear calibration equation were significantly larger than those associated with the use of the quadratic calibration equation. The position of the single control volume had no significant effect on the mean resultant errors in computed three dimensional coordinates when the quadratic calibration equation was used. Under the same data collection conditions, the mean resultant errors in the computed three dimensional coordinates associated with the panning and stationary DLT methods were 17 and 22 mm, respectively. The major advantages of the panning DLT method lie in the large image sizes obtained and in the ease with which the data can be collected. The method also has potential for use in a wide variety of contexts. The major shortcoming of the method is the large amount of digitizing necessary to calibrate the total control volume. Adaptations of the method to reduce the amount of digitizing required are being explored.

An Agent Based Collaborative Simplification of 3D Mesh Model

NASA Astrophysics Data System (ADS)

Wang, Li-Rong; Yu, Bo; Hagiwara, Ichiro

Large-volume mesh model faces the challenge in fast rendering and transmission by Internet. The current mesh models obtained by using three-dimensional (3D) scanning technology are usually very large in data volume. This paper develops a mobile agent based collaborative environment on the development platform of mobile-C. Communication among distributed agents includes grasping image of visualized mesh model, annotation to grasped image and instant message. Remote and collaborative simplification can be efficiently conducted by Internet.

Web tools for large-scale 3D biological images and atlases

PubMed Central

2012-01-01

Background Large-scale volumetric biomedical image data of three or more dimensions are a significant challenge for distributed browsing and visualisation. Many images now exceed 10GB which for most users is too large to handle in terms of computer RAM and network bandwidth. This is aggravated when users need to access tens or hundreds of such images from an archive. Here we solve the problem for 2D section views through archive data delivering compressed tiled images enabling users to browse through very-large volume data in the context of a standard web-browser. The system provides an interactive visualisation for grey-level and colour 3D images including multiple image layers and spatial-data overlay. Results The standard Internet Imaging Protocol (IIP) has been extended to enable arbitrary 2D sectioning of 3D data as well a multi-layered images and indexed overlays. The extended protocol is termed IIP3D and we have implemented a matching server to deliver the protocol and a series of Ajax/Javascript client codes that will run in an Internet browser. We have tested the server software on a low-cost linux-based server for image volumes up to 135GB and 64 simultaneous users. The section views are delivered with response times independent of scale and orientation. The exemplar client provided multi-layer image views with user-controlled colour-filtering and overlays. Conclusions Interactive browsing of arbitrary sections through large biomedical-image volumes is made possible by use of an extended internet protocol and efficient server-based image tiling. The tools open the possibility of enabling fast access to large image archives without the requirement of whole image download and client computers with very large memory configurations. The system was demonstrated using a range of medical and biomedical image data extending up to 135GB for a single image volume. PMID:22676296

Merchantable height of trees in Oregon—a comparison of current logging practice and volume table specifications.

Treesearch

Don Minore; Donald R. Gedney

1960-01-01

A large proportion of present-day timber cruising is done by measuring or estimating three tree dimensions: diameter at breast height, form class, and merchantable height. Tree volumes are then determined from tables which equate volume to the varying combinations of height, d.b.h., and form class. Assumptions concerning merchantable height were made in constructing...

Preconcentrator with high volume chiller for high vapor pressure particle detection

DOEpatents

Linker, Kevin L

2013-10-22

Apparatus and method for collecting particles of both high and low vapor pressure target materials entrained in a large volume sample gas stream. Large volume active cooling provides a cold air supply which is mixed with the sample gas stream to reduce the vapor pressure of the particles. In embodiments, a chiller cools air from ambient conditions to 0-15.degree. C. with the volumetric flow rate of the cold air supply being at least equal to the volumetric flow rate of the sample gas stream. In further embodiments an adsorption media is heated in at least two stages, a first of which is below a threshold temperature at which decomposition products of the high vapor pressure particle are generated.

Wayside Energy Storage Study : Volume 2. Detailed Description of Analysis.

DOT National Transportation Integrated Search

1979-02-01

Volume II summarizes an in-depth application study which was conducted to determine the practicality and viability of using large wayside flywheels to recuperate braking energy from freight trains on long downgrades. The study examined the route stru...

Risk factors associated with high potential for serious crashes.

DOT National Transportation Integrated Search

2015-09-01

Crashes are random events and low traffic volumes therefore dont always make crash hot-spot : identification possible. This project has used extensive data collection and analysis for a large sample : of Oregons low volume roads to develop a ri...

Study of Automobile Market Dynamics : Volume 2. Analysis.

DOT National Transportation Integrated Search

1977-08-01

Volume II describes the work in providing statistical inputs to a computer model by examining the effects of various options on the number of automobiles sold; the distribution of sales among small, medium and large cars; the distribution between aut...

Effects of Long-Term Treatment on Brain Volume in Patients with Obstructive Sleep Apnea Syndrome

PubMed Central

Kim, Hosung; Joo, Eun Yeon; Suh, Sooyeon; Kim, Jae-Hun; Kim, Sung Tae; Hong, Seung Bong

2015-01-01

We assessed structural brain damage in obstructive sleep apnea syndrome (OSA) patients (21 males) and the effects of long-term continuous positive airway pressure (CPAP) treatment (18.2 ± 12.4 months; 8-44 months) on brain structures and investigated the relationship between severity of OSA and effects of treatment. Using deformation-based morphometry to measure local volume changes, we identified widespread neocortical and cerebellar atrophy in untreated patients compared to controls (59 males; Cohen's D = 0.6; FDR < 0.05). Analysis of longitudinally scanned magnetic resonance imaging (MRI) scans both before and after treatment showed increased brain volume following treatment (FDR < 0.05). Volume increase was correlated with longer treatment in the cortical areas that largely overlapped with the initial atrophy. The areas overlying the hippocampal dentate gyrus and the cerebellar dentate nucleus displayed a volume increase after treatment. Patients with very severe OSA (AHI > 64) presented with prefrontal atrophy and displayed an additional volume increase in this area following treatment. Higher impairment of working memory in patients prior to treatment correlated with prefrontal volume increase after treatment. The large overlap between the initial brain damage and the extent of recovery after treatment suggests partial recovery of non-permanent structural damage. Volume increases in the dentate gyrus and the dentate nucleus possibly likely indicate compensatory neurogenesis in response to diminishing oxidative stress. Such changes in other brain structures may explain gliosis, dendritic volume increase, or inflammation. This study provides neuroimaging evidence that revealed the positive effects of long-term CPAP treatment in patients with OSA. PMID:26503297

Influence of large hiatus hernia on cardiac volumes. A prospective observational cohort study by cardiovascular magnetic resonance.

PubMed

Milito, Pamela; Lombardi, Massimo; Asti, Emanuele; Bonitta, Gianluca; Fina, Dario; Bandera, Francesco; Bonavina, Luigi

2018-05-09

Large hiatus hernia (LHH) is often associated with post-prandial dyspnea, palpitations or chest discomfort, but its effect on cardiac volumes and performance is still debated. Before and 3-months after laparoscopic repair, 35 patients underwent cardiovascular magnetic resonance (CMR) in the fasting state and after a standardized meal. Preoperatively, LHH size increased significantly after meal (p < 0.010). Compared to the fasting state, a systematic trend of volume reduction of the cardiac chambers was observed. In addition, both the left ventricle stroke volume (p = 0.012) and the ejection fraction (p = 0.010) were significantly reduced. At 3-months after surgery there was a statistically significant increase in left atrial volume (p = 0.029), overall left ventricle volume (p < 0.05) and right ventricle end-systolic volume (p = 0.046). Both FEV 1 (Forced expiratory volume) (p = 0.02) and FVC (Forced Vital Capacity) (p = 0.01) values significantly improved after surgery. Cardiorespiratory symptoms significantly improved compared to pre-operative values (p < 0.01). The global heart function was significantly impaired by a standardized meal in the presence of a LHH. Restoration of the cardiac physiological status and improvement of clinical symptoms were noted after surgery. A multidisciplinary evaluation and CMR with a challenge meal may be added to routine pre-operative testing to select symptomatic patients for surgical hernia repair. Copyright © 2017 Elsevier B.V. All rights reserved.

Eliminating the blood-flow confounding effect in intravoxel incoherent motion (IVIM) using the non-negative least square analysis in liver.

PubMed

Gambarota, Giulio; Hitti, Eric; Leporq, Benjamin; Saint-Jalmes, Hervé; Beuf, Olivier

2017-01-01

Tissue perfusion measurements using intravoxel incoherent motion (IVIM) diffusion-MRI are of interest for investigations of liver pathologies. A confounding factor in the perfusion quantification is the partial volume between liver tissue and large blood vessels. The aim of this study was to assess and correct for this partial volume effect in the estimation of the perfusion fraction. MRI experiments were performed at 3 Tesla with a diffusion-MRI sequence at 12 b-values. Diffusion signal decays in liver were analyzed using the non-negative least square (NNLS) method and the biexponential fitting approach. In some voxels, the NNLS analysis yielded a very fast-decaying component that was assigned to partial volume with the blood flowing in large vessels. Partial volume correction was performed by biexponential curve fitting, where the first data point (b = 0 s/mm 2 ) was eliminated in voxels with a very fast-decaying component. Biexponential fitting with partial volume correction yielded parametric maps with perfusion fraction values smaller than biexponential fitting without partial volume correction. The results of the current study indicate that the NNLS analysis in combination with biexponential curve fitting allows to correct for partial volume effects originating from blood flow in IVIM perfusion fraction measurements. Magn Reson Med 77:310-317, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Validation of deformable image registration algorithms on CT images of ex vivo porcine bladders with fiducial markers.

PubMed

Wognum, S; Heethuis, S E; Rosario, T; Hoogeman, M S; Bel, A

2014-07-01

The spatial accuracy of deformable image registration (DIR) is important in the implementation of image guided adaptive radiotherapy techniques for cancer in the pelvic region. Validation of algorithms is best performed on phantoms with fiducial markers undergoing controlled large deformations. Excised porcine bladders, exhibiting similar filling and voiding behavior as human bladders, provide such an environment. The aim of this study was to determine the spatial accuracy of different DIR algorithms on CT images of ex vivo porcine bladders with radiopaque fiducial markers applied to the outer surface, for a range of bladder volumes, using various accuracy metrics. Five excised porcine bladders with a grid of 30-40 radiopaque fiducial markers attached to the outer wall were suspended inside a water-filled phantom. The bladder was filled with a controlled amount of water with added contrast medium for a range of filling volumes (100-400 ml in steps of 50 ml) using a luer lock syringe, and CT scans were acquired at each filling volume. DIR was performed for each data set, with the 100 ml bladder as the reference image. Six intensity-based algorithms (optical flow or demons-based) implemented in theMATLAB platform DIRART, a b-spline algorithm implemented in the commercial software package VelocityAI, and a structure-based algorithm (Symmetric Thin Plate Spline Robust Point Matching) were validated, using adequate parameter settings according to values previously published. The resulting deformation vector field from each registration was applied to the contoured bladder structures and to the marker coordinates for spatial error calculation. The quality of the algorithms was assessed by comparing the different error metrics across the different algorithms, and by comparing the effect of deformation magnitude (bladder volume difference) per algorithm, using the Independent Samples Kruskal-Wallis test. The authors found good structure accuracy without dependency on bladder volume difference for all but one algorithm, and with the best result for the structure-based algorithm. Spatial accuracy as assessed from marker errors was disappointing for all algorithms, especially for large volume differences, implying that the deformations described by the registration did not represent anatomically correct deformations. The structure-based algorithm performed the best in terms of marker error for the large volume difference (100-400 ml). In general, for the small volume difference (100-150 ml) the algorithms performed relatively similarly. The structure-based algorithm exhibited the best balance in performance between small and large volume differences, and among the intensity-based algorithms, the algorithm implemented in VelocityAI exhibited the best balance. Validation of multiple DIR algorithms on a novel physiological bladder phantom revealed that the structure accuracy was good for most algorithms, but that the spatial accuracy as assessed from markers was low for all algorithms, especially for large deformations. Hence, many of the available algorithms exhibit sufficient accuracy for contour propagation purposes, but possibly not for accurate dose accumulation.

Quality evaluation of radiographic contrast media in large-volume prefilled syringes and vials.

PubMed

Sendo, T; Hirakawa, M; Yaginuma, M; Aoyama, T; Oishi, R

1998-06-01

The authors compared the particle contaminations of radiographic contrast media packaged in large-volume prefilled syringes and vials. Particle counting was performed for four contrast media packaged in large-volume prefilled syringes (iohexol, ioversol, ioversol for angiography, and ioxaglate) and three contrast media packaged in vials (iohexol, ioversol, and ioxaglate). X-ray emission spectrometry was performed to characterize the individual particles. The amount of silicone oil in the syringe was quantified with infrared spectrophotometry. The particle contamination in syringes containing ioversol was higher than that in syringes containing iohexol or ioxaglate. Particle contamination in the vials was relatively low, except with ioxaglate. X-ray emission spectrometry of the components of the syringe and vial showed that the source of particles was internal material released from the rubber stopper or inner surface. The particle counts for contrast media packaged in syringes and vials varied considerably among the different contrast media and were related to the amount of silicone oil on the inner surface and rubber piston of the syringe.

Metrological tests of a 200 L calibration source for HPGE detector systems for assay of radioactive waste drums.

PubMed

Boshkova, T; Mitev, K

2016-03-01

In this work we present test procedures, approval criteria and results from two metrological inspections of a certified large volume (152)Eu source (drum about 200L) intended for calibration of HPGe gamma assay systems used for activity measurement of radioactive waste drums. The aim of the inspections was to prove the stability of the calibration source during its working life. The large volume source was designed and produced in 2007. It consists of 448 identical sealed radioactive sources (modules) apportioned in 32 transparent plastic tubes which were placed in a wooden matrix which filled the drum. During the inspections the modules were subjected to tests for verification of their certified characteristics. The results show a perfect compliance with the NIST basic guidelines for the properties of a radioactive certified reference material (CRM) and demonstrate the stability of the large volume CRM-drum after 7 years of operation. Copyright © 2015 Elsevier Ltd. All rights reserved.

Pore Structure and Fluoride Ion Adsorption Characteristics of Zr (IV) Surface-Immobilized Resin Prepared Using Polystyrene as a Porogen

NASA Astrophysics Data System (ADS)

Mizuki, Hidenobu; Ito, Yudai; Harada, Hisashi; Uezu, Kazuya

Zr(IV) surface-immobilized resins for removal of fluoride ion were prepared by surface template polymerization using polystyrene as a porogen. At polymerization, polystyrene was added in order to increase mesopores (2-50 nm) and macropore (>50 nm) with large macropores (around 300 nm) formed with internal aqueous phase of W⁄O emulsion. The pore structure of Zr(IV) surface-immobilized resins was evaluated by measuring specific surface area, pore volume, and pore size distribution with volumetric adsorption measurement instrument and mercury porosimeter. The adsorption isotherms were well fitted by Langmuir equation. The removal of fluoride was also carried out with column method. Zr(IV) surface-immobilized resins, using 10 g⁄L polystyrene in toluene at polymerization, possessed higher volume of not only mesopores and macropores but also large macropores. Furethermore, by adding the polystyrene with smaller molecular size, the pore volume of mesopores, macropores and large macropores was significantly increased, and the fluoride ion adsorption capacity and the column utilization also increased.

Sparse PDF Volumes for Consistent Multi-Resolution Volume Rendering.

PubMed

Sicat, Ronell; Krüger, Jens; Möller, Torsten; Hadwiger, Markus

2014-12-01

This paper presents a new multi-resolution volume representation called sparse pdf volumes, which enables consistent multi-resolution volume rendering based on probability density functions (pdfs) of voxel neighborhoods. These pdfs are defined in the 4D domain jointly comprising the 3D volume and its 1D intensity range. Crucially, the computation of sparse pdf volumes exploits data coherence in 4D, resulting in a sparse representation with surprisingly low storage requirements. At run time, we dynamically apply transfer functions to the pdfs using simple and fast convolutions. Whereas standard low-pass filtering and down-sampling incur visible differences between resolution levels, the use of pdfs facilitates consistent results independent of the resolution level used. We describe the efficient out-of-core computation of large-scale sparse pdf volumes, using a novel iterative simplification procedure of a mixture of 4D Gaussians. Finally, our data structure is optimized to facilitate interactive multi-resolution volume rendering on GPUs.

Have Large Dams Altered Extreme Precipitation Patterns?

NASA Astrophysics Data System (ADS)

Hossain, Faisal; Jeyachandran, Indumathi; Pielke, Roger

2009-12-01

Dams and their impounded waters are among the most common civil infrastructures, with a long heritage of modern design and operations experience. In particular, large dams, defined by the International Commission on Large Dams (ICOLD) as having a height greater than 15 meters from the foundation and holding a reservoir volume of more than 3 million cubic meters, have the potential to vastly transform local climate, landscapes, regional economics, and urbanization patterns. In the United States alone, about 75,000 dams are capable of storing a volume of water equaling almost 1 year's mean runoff of the nation [Graf, 1999]. The World Commission on Dams (WCD) reports that at least 45,000 large dams have been built worldwide since the 1930s. These sheer numbers raise the question of the extent to which large dams and their impounded waters alter patterns that would have been pervasive had the dams not been built.

REGIONAL METHODS INITIATIVE RESEARCH PROJECTS AT HEASD

EPA Science Inventory

EPA Regional Laboratories are currently using high volume samplers with a combination of filter and sorbent vapor trap to collect large volume samples (250 liter/min for 24 hours) of semi-volatile organic compounds (SVOCs) and non-volatile organic compounds (NVOCs). These are su...

Recombinant factor VIIa as an adjunctive therapy for patients requiring large volume transfusion: a pharmacoeconomic evaluation.

PubMed

Loudon, B; Smith, M P

2005-08-01

Acute haemorrhage requiring large volume transfusion presents a costly and unpredictable risk to transfusion services. Recombinant factor VIIa (rFVIIa) (NovoSeven, Novo Nordisk, Bagsvaard, Denmark) may provide an important adjunctive haemostatic strategy for the management of patients requiring large volume blood transfusions. To review blood transfusion over a 12-month period and assess the major costs associated with haemorrhage management. A pharmoeconomic evaluation of rFVIIa intervention for large volume transfusion was conducted to identify the most cost-effective strategy for using this haemostatic product. Audit and analysis of all patients admitted to Christchurch Public Hospital requiring > 5 units of red blood cells (RBC) during a single transfusion episode. Patients were stratified into groups dependent on RBC units received and further stratified with regard to ward category. Cumulative costs were derived to compare standard treatment with an hypothesized rFVIIa intervention for each transfusion group. Sensitivity analyses were performed by varying parameters and comparing to original outcomes. Comparison of costs between the standard and hypothetical model indicated no statistically significant differences between groups (P < 0.05). Univariate and multivariate sensitivity analyses indicate that intervention with rFVIIa after transfusion of 14 RBC units may be cost-effective due to conservation of blood components and reduction in duration of intensive area stay. Intervention with rFVIIa for haemorrhage control is most cost-effective relatively early in the RBC transfusion period. Our hypothetical model indicates the optimal time point is when 14 RBC units have been transfused.

Increasing preoperative body size in breast cancer patients between 2002 and 2016: implications for prognosis.

PubMed

Wisse, Agatha; Tryggvadottir, Helga; Simonsson, Maria; Isaksson, Karolin; Rose, Carsten; Ingvar, Christian; Jernström, Helena

2018-05-26

Overweight and obesity are increasing worldwide, but the extent in breast cancer patients is unknown. The two aims were to study secular trends in preoperative body mass index (BMI), waist circumference, and breast volume and their impacts on clinical outcome. BMI, waist circumference, and breast volume were measured preoperatively in 24-99-year-old primary breast cancer patients (n = 640) in Sweden 2002-2016. The measurements were analyzed alone and combined in relation to recurrence and overall survival (OS). BMI, waist circumference, and breast volume increased 2002-2016 (p trends  < 0.0001). Of these, a breast volume ≥ 850 mL was associated with the strongest recurrence-risk (adjusted hazard ratio [ adj HR] 1.67; 95% CI 1.17-2.39), especially combined with waist circumference ≥ 80 cm ( adj HR 2.07; 95% CI 1.25-3.44), while BMI ≥ 25 kg/m 2 or large waist circumference conferred almost a twofold risk for death (both Log-Rank p ≤ 0.0001). Chemotherapy seemed to counteract the negative impact of a high BMI or large waist circumference on OS. Large breast volume was the strongest predictor for recurrence in all treatment groups. In conclusion, preoperative BMI, waist circumference, and breast volume increased between 2002 and 2016. Larger body size negatively impacted breast cancer-free interval and OS. If confirmed, body measurements may help select patients requiring more individualized treatment.

Atmospheric Gaseous Plasma with Large Dimensions

NASA Astrophysics Data System (ADS)

Korenev, Sergey

2012-10-01

The forming of atmospheric plasma with large dimensions using electrical discharge typically uses the Dielectric Barrier Discharge (DBD). The study of atmospheric DBD was shown some problems related to homogeneous volume plasma. The volume of this plasma determines by cross section and gas gap between electrode and dielectric. The using of electron beam for volume ionization of air molecules by CW relativistic electron beams was shown the high efficiency of this process [1, 2]. The main advantage of this approach consists in the ionization of gas molecules by electrons in longitudinal direction determines by their kinetic energy. A novel method for forming of atmospheric homogeneous plasma with large volume dimensions using ionization of gas molecules by pulsed non-relativistic electron beams is presented in the paper. The results of computer modeling for delivered doses of electron beams in gases and ionization are discussed. The structure of experimental bench with plasma diagnostics is considered. The preliminary results of forming atmospheric plasma with ionization gas molecules by pulsed nanosecond non-relativistic electron beam are given. The analysis of potential applications for atmospheric volume plasma is presented. Reference: [1] S. Korenev. ``The ionization of air by scanning relativistic high power CW electron beam,'' 2002 IEEE International Conference on Plasma Science. May 2002, Alberta, Canada. [2] S. Korenev, I. Korenev. ``The propagation of high power CW scanning electron beam in air.'' BEAMS 2002: 14th International Conference on High-Power Particle Beams, Albuquerque, New Mexico (USA), June 2002, AIP Conference Proceedings Vol. 650(1), pp. 373-376. December 17.

Serial Section Scanning Electron Microscopy (S3EM) on Silicon Wafers for Ultra-Structural Volume Imaging of Cells and Tissues

PubMed Central

Horstmann, Heinz; Körber, Christoph; Sätzler, Kurt; Aydin, Daniel; Kuner, Thomas

2012-01-01

High resolution, three-dimensional (3D) representations of cellular ultrastructure are essential for structure function studies in all areas of cell biology. While limited subcellular volumes have been routinely examined using serial section transmission electron microscopy (ssTEM), complete ultrastructural reconstructions of large volumes, entire cells or even tissue are difficult to achieve using ssTEM. Here, we introduce a novel approach combining serial sectioning of tissue with scanning electron microscopy (SEM) using a conductive silicon wafer as a support. Ribbons containing hundreds of 35 nm thick sections can be generated and imaged on the wafer at a lateral pixel resolution of 3.7 nm by recording the backscattered electrons with the in-lens detector of the SEM. The resulting electron micrographs are qualitatively comparable to those obtained by conventional TEM. S3EM images of the same region of interest in consecutive sections can be used for 3D reconstructions of large structures. We demonstrate the potential of this approach by reconstructing a 31.7 µm3 volume of a calyx of Held presynaptic terminal. The approach introduced here, Serial Section SEM (S3EM), for the first time provides the possibility to obtain 3D ultrastructure of large volumes with high resolution and to selectively and repetitively home in on structures of interest. S3EM accelerates process duration, is amenable to full automation and can be implemented with standard instrumentation. PMID:22523574

Serial section scanning electron microscopy (S3EM) on silicon wafers for ultra-structural volume imaging of cells and tissues.

PubMed

Horstmann, Heinz; Körber, Christoph; Sätzler, Kurt; Aydin, Daniel; Kuner, Thomas

2012-01-01

High resolution, three-dimensional (3D) representations of cellular ultrastructure are essential for structure function studies in all areas of cell biology. While limited subcellular volumes have been routinely examined using serial section transmission electron microscopy (ssTEM), complete ultrastructural reconstructions of large volumes, entire cells or even tissue are difficult to achieve using ssTEM. Here, we introduce a novel approach combining serial sectioning of tissue with scanning electron microscopy (SEM) using a conductive silicon wafer as a support. Ribbons containing hundreds of 35 nm thick sections can be generated and imaged on the wafer at a lateral pixel resolution of 3.7 nm by recording the backscattered electrons with the in-lens detector of the SEM. The resulting electron micrographs are qualitatively comparable to those obtained by conventional TEM. S(3)EM images of the same region of interest in consecutive sections can be used for 3D reconstructions of large structures. We demonstrate the potential of this approach by reconstructing a 31.7 µm(3) volume of a calyx of Held presynaptic terminal. The approach introduced here, Serial Section SEM (S(3)EM), for the first time provides the possibility to obtain 3D ultrastructure of large volumes with high resolution and to selectively and repetitively home in on structures of interest. S(3)EM accelerates process duration, is amenable to full automation and can be implemented with standard instrumentation.

High-frequency strontium vapor laser for biomedical applications

NASA Astrophysics Data System (ADS)

Hvorostovsky, A.; Kolmakov, E.; Kudashev, I.; Redka, D.; Kancer, A.; Kustikova, M.; Bykovskaya, E.; Mayurova, A.; Stupnikov, A.; Ruzankina, J.; Tsvetkov, K.; Lukyanov, N.; Paklinov, N.

2018-02-01

Sr-laser with high pulse repetition rate and high peak radiation power is a unique tool for studying rapidly occurring processes in time (plasma diagnostics, photoablation, etc.). In addition, the study of the frequency characteristics of the active medium of the laser helps to reveal the physics of the formation of an inverse medium in metal vapor lasers. In this paper, an experimental study of an Sr-laser with an active volume of 5.8 cm3 in the pulse repetition frequency range from 25 to 200 kHz is carried out, and a comparison with the frequency characteristics of media with large active volumes is given. We considered the frequency characteristics of the active medium in two modes: at a constant energy in the excitation pulse CU2 / 2 and at a constant average power consumed by the rectifier. In the presented work with a small-volume GRT using the TASITR-5/12 TASITRON switch, a laser was generated for Pairs of strontium at a CSF of 200 kHz. The behavior of the characteristics of the generation lines of 6.456 μm, 1 μm, and 3 μm at increased repetition frequencies is considered. Using the example of large-volume GRT, it is shown that tubes with a large active volume increase their energy characteristics with the growth of the CSF. The possibility of laser operation at pulse repetition rates above 200 kHz is shown.

Gravity Recovery and Climate Experiment (GRACE) detection of water storage changes in the Three Gorges Reservoir of China and comparison with in situ measurements

NASA Astrophysics Data System (ADS)

Wang, Xianwei; de Linage, Caroline; Famiglietti, James; Zender, Charles S.

2011-12-01

Water impoundment in the Three Gorges Reservoir (TGR) of China caused a large mass redistribution from the oceans to a concentrated land area in a short time period. We show that this mass shift is captured by the Gravity Recovery and Climate Experiment (GRACE) unconstrained global solutions at a 400 km spatial resolution after removing correlated errors. The WaterGAP Global Hydrology Model (WGHM) is selected to isolate the TGR contribution from regional water storage changes. For the first time, this study compares the GRACE (minus WGHM) estimated TGR volume changes with in situ measurements from April 2002 to May 2010 at a monthly time scale. During the 8 year study period, GRACE-WGHM estimated TGR volume changes show an increasing trend consistent with the TGR in situ measurements and lead to similar estimates of impounded water volume. GRACE-WGHM estimated total volume increase agrees to within 14% (3.2 km3) of the in situ measurements. This indicates that GRACE can retrieve the true amplitudes of large surface water storage changes in a concentrated area that is much smaller than the spatial resolution of its global harmonic solutions. The GRACE-WGHM estimated TGR monthly volume changes explain 76% (r2 = 0.76) of in situ measurement monthly variability and have an uncertainty of 4.62 km3. Our results also indicate reservoir leakage and groundwater recharge due to TGR filling and contamination from neighboring lakes are nonnegligible in the GRACE total water storage changes. Moreover, GRACE observations could provide a relatively accurate estimate of global water volume withheld by newly constructed large reservoirs and their impacts on global sea level rise since 2002.

PROGRAM HTVOL: The Determination of Tree Crown Volume by Layers

Treesearch

Joseph C. Mawson; Jack Ward Thomas; Richard M. DeGraaf

1976-01-01

A FORTRAN IV computer program calculates, from a few field measurements, the volume of tree crowns. This volume is in layers of a specified thickness of trees or large shrubs. Each tree is assigned one of 15 solid forms, formed by using one of five side shapes (a circle, an ellipse, a neiloid, a triangle, or a parabolalike shape), and one of three bottom shapes (a...

Important influence of respiration on human R-R interval power spectra is largely ignored

NASA Technical Reports Server (NTRS)

Brown, T. E.; Beightol, L. A.; Koh, J.; Eckberg, D. L.

1993-01-01

Frequency-domain analyses of R-R intervals are used widely to estimate levels of autonomic neural traffic to the human heart. Because respiration modulates autonomic activity, we determined for nine healthy subjects the influence of breathing frequency and tidal volume on R-R interval power spectra (fast-Fourier transform method). We also surveyed published literature to determine current practices in this burgeoning field of scientific inquiry. Supine subjects breathed at rates of 6, 7.5, 10, 15, 17.1, 20, and 24 breaths/min and with nominal tidal volumes of 1,000 and 1,500 ml. R-R interval power at respiratory and low (0.06-0.14 Hz) frequencies declined significantly as breathing frequency increased. R-R interval power at respiratory frequencies was significantly greater at a tidal volume of 1,500 than 1,000 ml. Neither breathing frequency nor tidal volume influenced average R-R intervals significantly. Our review of studies reporting human R-R interval power spectra showed that 51% of the studies controlled respiratory rate, 11% controlled tidal volume, and 11% controlled both respiratory rate and tidal volume. The major implications of our analyses are that breathing parameters strongly influence low-frequency as well as respiratory frequency R-R interval power spectra and that this influence is largely ignored in published research.

GPU-based multi-volume ray casting within VTK for medical applications.

PubMed

Bozorgi, Mohammadmehdi; Lindseth, Frank

2015-03-01

Multi-volume visualization is important for displaying relevant information in multimodal or multitemporal medical imaging studies. The main objective with the current study was to develop an efficient GPU-based multi-volume ray caster (MVRC) and validate the proposed visualization system in the context of image-guided surgical navigation. Ray casting can produce high-quality 2D images from 3D volume data but the method is computationally demanding, especially when multiple volumes are involved, so a parallel GPU version has been implemented. In the proposed MVRC, imaginary rays are sent through the volumes (one ray for each pixel in the view), and at equal and short intervals along the rays, samples are collected from each volume. Samples from all the volumes are composited using front to back α-blending. Since all the rays can be processed simultaneously, the MVRC was implemented in parallel on the GPU to achieve acceptable interactive frame rates. The method is fully integrated within the visualization toolkit (VTK) pipeline with the ability to apply different operations (e.g., transformations, clipping, and cropping) on each volume separately. The implemented method is cross-platform (Windows, Linux and Mac OSX) and runs on different graphics card (NVidia and AMD). The speed of the MVRC was tested with one to five volumes of varying sizes: 128(3), 256(3), and 512(3). A Tesla C2070 GPU was used, and the output image size was 600 × 600 pixels. The original VTK single-volume ray caster and the MVRC were compared when rendering only one volume. The multi-volume rendering system achieved an interactive frame rate (> 15 fps) when rendering five small volumes (128 (3) voxels), four medium-sized volumes (256(3) voxels), and two large volumes (512(3) voxels). When rendering single volumes, the frame rate of the MVRC was comparable to the original VTK ray caster for small and medium-sized datasets but was approximately 3 frames per second slower for large datasets. The MVRC was successfully integrated in an existing surgical navigation system and was shown to be clinically useful during an ultrasound-guided neurosurgical tumor resection. A GPU-based MVRC for VTK is a useful tool in medical visualization. The proposed multi-volume GPU-based ray caster for VTK provided high-quality images at reasonable frame rates. The MVRC was effective when used in a neurosurgical navigation application.

The Long-Term Effects of Large Wood Placement on Salmonid Habitat in East Fork Mill Creek, Redwood National and State Park, California

NASA Astrophysics Data System (ADS)

Rodriguez, D. L.; Stubblefield, A. P.

2017-12-01

The conservation and recovery of anadromous salmonids (Oncorhynchus sp.) depend on stream restoration and protection of freshwater habitats. Instream large wood dictates channel morphology, increase retention of terrestrial inputs such as organic matter, nutrients and sediment, and enhances the quality of fish habitat. Historic land use/land cover changes have resulted in aquatic systems devoid of this component. Restoration by placement of large wood jams is intended to restore physical and biological processes. An important question for scientists and managers, in addition to the initial effectiveness of restoration, is the persistence and fate of this type of project. In this study we compare channel change and large wood attributes on the East Fork of Mill Creek, a tributary of the Smith River in northern California, eight years after a major instream wood placement effort took place. Our results are compared with previously published data from before and one year after the restoration. Preliminary results suggest the dramatic increase in spawning gravel abundance and large wood accumulation observed in the earlier study have persisted. From 2008 to 2016 a reduction in median sediment size, ranging from 103-136 percent, has been observed in a majority of the sites. The sites have continued to grow in size and influence by racking floating wood from upstream and destabilizing proximate banks of riparian alder, increasing both instream large wood volume (5-196 %) and floodplain connectivity. Preliminary results also show a decrease in residual pool depth and an increase in pool length which may be attributed to floodplain connectivity. Changes to the following attributes are evaluated: 1) wood loading (total site wood volume, total wood volume in active channel, and wood piece count); 2) percent pool cover by large wood; 3) residual pool depth; 4) upstream sediment aggradation; 5) floodplain connectivity; and 6) mean sediment size directly above and below large wood. We present on these results and statistical comparisons of total site wood volume with response factors.

Design of Large Stone Asphalt Mixes for Low-Volume Roads Using Six-Inch Diameter Marshall Specimens

DOT National Transportation Integrated Search

1991-01-01

Premature rutting of road pavements constructed for hauling coal and logs is common. Although these roads carry low volumes of traffic, they are subjected to heavy and channelized wheel loads. Unfortunately, conventional asphalt mixes containing aggr...

Dynamics of 30 large channel bars in the Lower Mississippi River in response to river engineering from 1985 to 2015

NASA Astrophysics Data System (ADS)

Wang, Bo; Xu, Y. Jun

2018-01-01

Channel bars are a major depositional feature in alluvial rivers and their morphodynamics has been investigated intensively in the past several decades. However, relatively less is known about how channel bars in alluvial rivers respond to river engineering and regulations. In this study, we assessed 30-yr morphologic changes of 30 large emerged bars located in a 223 km reach of the highly regulated Lower Mississippi River from Vicksburg, Mississippi, to the Mississippi-Atchafalaya River diversion. Landsat imagery and river stage data between 1985 and 2015 were utilized to characterize bar morphologic features and quantify decadal changes. Based on bar surface areas estimated with the satellite images at different river stages, a rating curve was developed for each of the 30 bars to determine their volumes. Results from this study show that the highly regulated river reach favored the growth of mid-channel and attached bars, while more than half of the point bars showed degradation. Currently, the mid-channel and attached bars accounted for 38% and 34% of the total volume of the 30 bars. The average volume of a single mid-channel bar is over two times that of an attached bar and over four times that of a point bar. Overall, in the past three decades, the total volume of the studied 30 bars increased by 110,118,000 m3 (41%). Total dike length in a dike field was found mostly contributing to the bar volume increase. Currently, the emerged volume of the 30 bars was estimated approximately 378,183,000 m3. The total bar volume is equivalent to 530 million metric tons of coarse sand, based on an average measured bulk density of 1.4 t/m3 for the bar sediment. The findings show that these bars are large sediment reservoirs.

High failure rates after (131)I therapy in Graves hyperthyroidism patients with large thyroid volumes, high iodine uptake, and high iodine turnover.

PubMed

de Jong, Jeroen A F; Verkooijen, Helena M; Valk, Gerlof D; Zelissen, Pierre M J; de Keizer, Bart

2013-06-01

The objective of this study was to identify patient characteristics positively and independently associated with I-iodide treatment failure in a large cohort of patients with Graves hyperthyroidism treated with either a calculated "standard" activity of 3.7 MBq/mL (0.1 mCi) or 7.4 MBq/mL (0.2 mCi) of thyroid volume. Data on 385 consecutive patients were prospectively collected. Clinical treatment outcome up to 1 year in relation to thyroid volume, 5- and 24-hour I uptake, 5/24-hour I uptake ratio, and the administered activity of radioiodine were analyzed. Overall treatment results were hypothyroidism in 46%, euthyroidism in 29%, and recurrent hyperthyroidism in 26% of patients. Thyroid volume (P = 0.000), 5/24-hour uptake ratio (P = 0.000), and 5- and 24-hour uptake alone (respectively, P = 0.000 and P = 0.002) were significantly associated with therapy outcome. Patients with a combination of a thyroid volume greater than 50 mL and a 5/24-hour uptake ratio 0.8 or greater showed treatment failure in 70% and 42% (respectively, 3.7 MBq/mL, n = 20; and 7.4 MBq/mL, n = 41).Thyroid volume and 5/24-hour uptake ratio were positively and independently associated with recurrent hyperthyroidism (respectively, odds ratio [OR], 5.3; 95% confidence interval [CI], 2.39-11.76; and OR, 2.97; 95% CI, 1.59-5.59). Higher activities of 7.4 MBq/mL I were associated with a lower risk of treatment failure (OR, 0.34; 95% CI, 0.18-0.62). Large thyroid volumes and high 5/24-hour uptake ratios are positively and independently associated with recurrent hyperthyroidism following I therapy in Graves hyperthyroidism. Higher success rates can be achieved when account is taken of these poor prognostic factors. In consequence, these patients should be treated with activities greater than 7.4 MBq/mL.

Errors in Measuring Water Potentials of Small Samples Resulting from Water Adsorption by Thermocouple Psychrometer Chambers 1

PubMed Central

Bennett, Jerry M.; Cortes, Peter M.

1985-01-01

The adsorption of water by thermocouple psychrometer assemblies is known to cause errors in the determination of water potential. Experiments were conducted to evaluate the effect of sample size and psychrometer chamber volume on measured water potentials of leaf discs, leaf segments, and sodium chloride solutions. Reasonable agreement was found between soybean (Glycine max L. Merr.) leaf water potentials measured on 5-millimeter radius leaf discs and large leaf segments. Results indicated that while errors due to adsorption may be significant when using small volumes of tissue, if sufficient tissue is used the errors are negligible. Because of the relationship between water potential and volume in plant tissue, the errors due to adsorption were larger with turgid tissue. Large psychrometers which were sealed into the sample chamber with latex tubing appeared to adsorb more water than those sealed with flexible plastic tubing. Estimates are provided of the amounts of water adsorbed by two different psychrometer assemblies and the amount of tissue sufficient for accurate measurements of leaf water potential with these assemblies. It is also demonstrated that water adsorption problems may have generated low water potential values which in prior studies have been attributed to large cut surface area to volume ratios. PMID:16664367

Errors in measuring water potentials of small samples resulting from water adsorption by thermocouple psychrometer chambers.

PubMed

Bennett, J M; Cortes, P M

1985-09-01

The adsorption of water by thermocouple psychrometer assemblies is known to cause errors in the determination of water potential. Experiments were conducted to evaluate the effect of sample size and psychrometer chamber volume on measured water potentials of leaf discs, leaf segments, and sodium chloride solutions. Reasonable agreement was found between soybean (Glycine max L. Merr.) leaf water potentials measured on 5-millimeter radius leaf discs and large leaf segments. Results indicated that while errors due to adsorption may be significant when using small volumes of tissue, if sufficient tissue is used the errors are negligible. Because of the relationship between water potential and volume in plant tissue, the errors due to adsorption were larger with turgid tissue. Large psychrometers which were sealed into the sample chamber with latex tubing appeared to adsorb more water than those sealed with flexible plastic tubing. Estimates are provided of the amounts of water adsorbed by two different psychrometer assemblies and the amount of tissue sufficient for accurate measurements of leaf water potential with these assemblies. It is also demonstrated that water adsorption problems may have generated low water potential values which in prior studies have been attributed to large cut surface area to volume ratios.

Systems and methods for the detection of low-level harmful substances in a large volume of fluid

DOE Office of Scientific and Technical Information (OSTI.GOV)

Carpenter, Michael V.; Roybal, Lyle G.; Lindquist, Alan

A method and device for the detection of low-level harmful substances in a large volume of fluid comprising using a concentrator system to produce a retentate and analyzing the retentate for the presence of at least one harmful substance. The concentrator system performs a method comprising pumping at least 10 liters of fluid from a sample source through a filter. While pumping, the concentrator system diverts retentate from the filter into a container. The concentrator system also recirculates at least part of the retentate in the container again through the filter. The concentrator system controls the speed of the pumpmore » with a control system thereby maintaining a fluid pressure less than 25 psi during the pumping of the fluid; monitors the quantity of retentate within the container with a control system, and maintains a reduced volume level of retentate and a target volume of retentate.« less

Nontrivial thermodynamics in 't Hooft's large-N limit

NASA Astrophysics Data System (ADS)

Cubero, Axel Cortés

2015-05-01

We study the finite volume/temperature correlation functions of the (1 +1 )-dimensional SU (N ) principal chiral sigma model in the planar limit. The exact S-matrix of the sigma model is known to simplify drastically at large N , and this leads to trivial thermodynamic Bethe ansatz (TBA) equations. The partition function, if derived using the TBA, can be shown to be that of free particles. We show that the correlation functions and expectation values of operators at finite volume/temperature are not those of the free theory, and that the TBA does not give enough information to calculate them. Our analysis is done using the Leclair-Mussardo formula for finite-volume correlators, and knowledge of the exact infinite-volume form factors. We present analytical results for the one-point function of the energy-momentum tensor, and the two-point function of the renormalized field operator. The results for the energy-momentum tensor can be used to define a nontrivial partition function.

Assessment of artificial recharge at Sand Hollow Reservoir, Washington County, Utah, Updated to Conditions through 2006

USGS Publications Warehouse

Heilweil, Victor M.; Susong, David D.

2007-01-01

Sand Hollow, Utah, is the site of a surface-water reservoir completed in March 2002 and operated by the Washington County Water Conservancy District (WCWCD) primarily as an aquifer storage and recovery project. The reservoir is an off-channel facility that receives water from the Virgin River, diverted near the town of Virgin, Utah. Hydrologic data collected are described and listed in this report, including ground-water levels, reservoir stage, reservoir-water temperature, meteorology, evaporation, and estimated ground-water recharge. Since the construction of the reservoir in 2002, diversions from the Virgin River have resulted in generally rising stage and surface area. Large spring run-off volumes during 2005-06 allowed the WCWCD to fill the reservoir to near capacity, with a surface area of about 1,300 acres in 2006. Reservoir stage reached a record altitude of about 3,060 feet in May 2006, resulting in a depth of nearly 90 feet and a reservoir storage of about 51,000 acre-feet. Water temperature in the reservoir shows large seasonal variation and has ranged from about 5 to 32?C. Estimated ground-water recharge rates have ranged from 0.01 to 0.43 feet per day. Estimated recharge volumes have ranged from about 200 to about 3,500 acre-feet per month. Total ground-water recharge from March 2002 through August 2006 is estimated to be about 51,000 acre-feet. Estimated evaporation rates have varied from 0.05 to 0.97 feet per month, resulting in evaporation losses of 20 to 1,200 acre-feet per month. Total evaporation from March 2002 through August 2006 is estimated to be about 17,000 acre-feet. The combination of generally declining recharge rates and increasing reservoir altitude and area explains the trend of an increasing ratio of evaporation to recharge volume over time, with the total volume of water lost through evaporation nearly as large as the volume of ground-water recharge during the first 8 months of 2006. With removal of the viscosity effects (caused by seasonal water temperature variations), the intrinsic permeability indicates a large seasonal variation in clogging, with large winter increases likely caused by a combination of both decreased biofilms and the reduced volume of trapped gas bubbles.

The largest volcanic eruptions on Earth

NASA Astrophysics Data System (ADS)

Bryan, Scott E.; Peate, Ingrid Ukstins; Peate, David W.; Self, Stephen; Jerram, Dougal A.; Mawby, Michael R.; Marsh, J. S. (Goonie); Miller, Jodie A.

2010-10-01

Large igneous provinces (LIPs) are sites of the most frequently recurring, largest volume basaltic and silicic eruptions in Earth history. These large-volume (> 1000 km 3 dense rock equivalent) and large-magnitude (> M8) eruptions produce areally extensive (10 4-10 5 km 2) basaltic lava flow fields and silicic ignimbrites that are the main building blocks of LIPs. Available information on the largest eruptive units are primarily from the Columbia River and Deccan provinces for the dimensions of flood basalt eruptions, and the Paraná-Etendeka and Afro-Arabian provinces for the silicic ignimbrite eruptions. In addition, three large-volume (675-2000 km 3) silicic lava flows have also been mapped out in the Proterozoic Gawler Range province (Australia), an interpreted LIP remnant. Magma volumes of > 1000 km 3 have also been emplaced as high-level basaltic and rhyolitic sills in LIPs. The data sets indicate comparable eruption magnitudes between the basaltic and silicic eruptions, but due to considerable volumes residing as co-ignimbrite ash deposits, the current volume constraints for the silicic ignimbrite eruptions may be considerably underestimated. Magma composition thus appears to be no barrier to the volume of magma emitted during an individual eruption. Despite this general similarity in magnitude, flood basaltic and silicic eruptions are very different in terms of eruption style, duration, intensity, vent configuration, and emplacement style. Flood basaltic eruptions are dominantly effusive and Hawaiian-Strombolian in style, with magma discharge rates of ~ 10 6-10 8 kg s -1 and eruption durations estimated at years to tens of years that emplace dominantly compound pahoehoe lava flow fields. Effusive and fissural eruptions have also emplaced some large-volume silicic lavas, but discharge rates are unknown, and may be up to an order of magnitude greater than those of flood basalt lava eruptions for emplacement to be on realistic time scales (< 10 years). Most silicic eruptions, however, are moderately to highly explosive, producing co-current pyroclastic fountains (rarely Plinian) with discharge rates of 10 9-10 11 kg s -1 that emplace welded to rheomorphic ignimbrites. At present, durations for the large-magnitude silicic eruptions are unconstrained; at discharge rates of 10 9 kg s -1, equivalent to the peak of the 1991 Mt Pinatubo eruption, the largest silicic eruptions would take many months to evacuate > 5000 km 3 of magma. The generally simple deposit structure is more suggestive of short-duration (hours to days) and high intensity (~ 10 11 kg s -1) eruptions, perhaps with hiatuses in some cases. These extreme discharge rates would be facilitated by multiple point, fissure and/or ring fracture venting of magma. Eruption frequencies are much elevated for large-magnitude eruptions of both magma types during LIP-forming episodes. However, in basalt-dominated provinces (continental and ocean basin flood basalt provinces, oceanic plateaus, volcanic rifted margins), large magnitude (> M8) basaltic eruptions have much shorter recurrence intervals of 10 3-10 4 years, whereas similar magnitude silicic eruptions may have recurrence intervals of up to 10 5 years. The Paraná-Etendeka province was the site of at least nine > M8 silicic eruptions over an ~ 1 Myr period at ~ 132 Ma; a similar eruption frequency, although with a fewer number of silicic eruptions is also observed for the Afro-Arabian Province. The huge volumes of basaltic and silicic magma erupted in quick succession during LIP events raises several unresolved issues in terms of locus of magma generation and storage (if any) in the crust prior to eruption, and paths and rates of ascent from magma reservoirs to the surface. Available data indicate four end-member magma petrogenetic pathways in LIPs: 1) flood basalt magmas with primitive, mantle-dominated geochemical signatures (often high-Ti basalt magma types) that were either transferred directly from melting regions in the upper mantle to fissure vents at surface, or resided temporarily in reservoirs in the upper mantle or in mafic underplate thereby preventing extensive crustal contamination or crystallisation; 2) flood basalt magmas (often low-Ti types) that have undergone storage at lower ± upper crustal depths resulting in crustal assimilation, crystallisation, and degassing; 3) generation of high-temperature anhydrous, crystal-poor silicic magmas (e.g., Paraná-Etendeka quartz latites) by large-scale AFC processes involving lower crustal granulite melting and/or basaltic underplate remelting; and 4) rejuvenation of upper-crustal batholiths (mainly near-solidus crystal mush) by shallow intrusion and underplating by mafic magma providing thermal and volatile input to produce large volumes of crystal-rich (30-50%) dacitic to rhyolitic magma and for ignimbrite-producing eruptions, well-defined calderas up to 80 km diameter (e.g., Fish Canyon Tuff model), and which characterise of some silicic eruptions in silicic LIPs.

Novel Liquid Sorbent C02 Removal System for Microgravity Applications

NASA Technical Reports Server (NTRS)

Rogers, Tanya; Westover, Shayne; Graf, John

2017-01-01

Removing Carbon Dioxide (CO2) from a spacecraft environment for deep space exploration requires a robust system that is low in weight, power, and volume. Current state-of-the-art microgravity compatible CO2 removal systems, such as the carbon dioxide removal assembly (CDRA), utilize solid sorbents that demand high power usage due to high desorption temperatures and a large volume to accommodate for their comparatively low capacity for CO2. Additionally, solid sorbent systems contain several mechanical components that significantly reduce reliability and contribute to a large overall mass. A liquid sorbent based system has been evaluated as an alternative is proposed to consume 65% less power, weight, and volume than solid based CO2 scrubbers. This paper presents the design of a liquid sorbent CO2 removal system for microgravity applications.

High-Volume Production of Lightweight Multijunction Solar Cells

NASA Technical Reports Server (NTRS)

Youtsey, Christopher

2015-01-01

MicroLink Devices, Inc., has transitioned its 6-inch epitaxial lift-off (ELO) solar cell fabrication process into a manufacturing platform capable of sustaining large-volume production. This Phase II project improves the ELO process by reducing cycle time and increasing the yield of large-area devices. In addition, all critical device fabrication processes have transitioned to 6-inch production tool sets designed for volume production. An emphasis on automated cassette-to-cassette and batch processes minimizes operator dependence and cell performance variability. MicroLink Devices established a pilot production line capable of at least 1,500 6-inch wafers per month at greater than 80 percent yield. The company also increased the yield and manufacturability of the 6-inch reclaim process, which is crucial to reducing the cost of the cells.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Perry, F.V.; Valentine, G.A.; Crowe, B.M.

This is the final report of a one-year, Laboratory Directed Research and Development (LDRD) project at Los Alamos National Laboratory (LANL). The objective of this project was to determine whether isotopic techniques can be used to assess the eruption potential and eruption volume of continental stratovolcanoes. Large-volume eruptions from stratovolcanoes pose significant hazards to population and infrastructure in many parts of the world. We are testing whether this technique will allow a short- to medium-term (decades to millennia) probabilistic hazard assessment of large-volume eruptions. If successful, the technique will be useful to countries or regions that must consider medium tomore » long-term volcanic (e.g., nuclear waste facilities). We have begun sample acquisition and isotopic measurements at two stratovolcanoes, Pico de Orizaba in eastern Mexico and Daisen in western Japan.« less

Comparison of MRI segmentation techniques for measuring liver cyst volumes in autosomal dominant polycystic kidney disease.

PubMed

Farooq, Zerwa; Behzadi, Ashkan Heshmatzadeh; Blumenfeld, Jon D; Zhao, Yize; Prince, Martin R

To compare MRI segmentation methods for measuring liver cyst volumes in autosomal dominant polycystic kidney disease (ADPKD). Liver cyst volumes in 42 ADPKD patients were measured using region growing, thresholding and cyst diameter techniques. Manual segmentation was the reference standard. Root mean square deviation was 113, 155, and 500 for cyst diameter, thresholding and region growing respectively. Thresholding error for cyst volumes below 500ml was 550% vs 17% for cyst volumes above 500ml (p<0.001). For measuring volume of a small number of cysts, cyst diameter and manual segmentation methods are recommended. For severe disease with numerous, large hepatic cysts, thresholding is an acceptable alternative. Copyright © 2017 Elsevier Inc. All rights reserved.

Cooling Water Intakes

EPA Pesticide Factsheets

Industries use large volumes of water for cooling. The water intakes pull large numbers of fish and other organisms into the cooling systems. EPA issues regulations on intake structures in order to minimize adverse environmental impacts.

Response function and linearity for high energy γ-rays in large volume LaBr3:Ce detectors

NASA Astrophysics Data System (ADS)

Gosta, G.; Blasi, N.; Camera, F.; Million, B.; Giaz, A.; Wieland, O.; Rossi, F. M.; Utsunomiya, H.; Ari-izumi, T.; Takenaka, D.; Filipescu, D.; Gheorghe, I.

2018-01-01

The response function to high energy γ-rays of two large volume LaBr3:Ce crystals (3.5"x8") and the linearity of the coupled PMT's were investigated at the NewSUBARU facility, where γ-rays in the energy range 6-38 MeV were produced and sent into the detectors. Monte Carlo simulations were performed to reproduce the experimental spectra. The photopeak and interaction efficiencies were also evaluated both in case of a collimated beam and an isotropic source.

Incarceration of umbilical hernia: a rare complication of large volume paracentesis.

PubMed

Khodarahmi, Iman; Shahid, Muhammad Usman; Contractor, Sohail

2015-09-01

We present two cases of umbilical hernia incarceration following large volume paracentesis (LVP) in patients with cirrhotic ascites. Both patients became symptomatic within 48 hours after the LVP. Although being rare, given the significantly higher mortality rate of cirrhotic patients undergoing emergent herniorrhaphy, this complication of LVP is potentially serious. Therefore, it is recommended that patients be examined closely for the presence of umbilical hernias before removal of ascitic fluid and an attempt should be made for external reduction of easily reducible hernias, if a hernia is present.

Incarceration of umbilical hernia: a rare complication of large volume paracentesis

PubMed Central

Khodarahmi, Iman; Shahid, Muhammad Usman; Contractor, Sohail

2015-01-01

We present two cases of umbilical hernia incarceration following large volume paracentesis (LVP) in patients with cirrhotic ascites. Both patients became symptomatic within 48 hours after the LVP. Although being rare, given the significantly higher mortality rate of cirrhotic patients undergoing emergent herniorrhaphy, this complication of LVP is potentially serious. Therefore, it is recommended that patients be examined closely for the presence of umbilical hernias before removal of ascitic fluid and an attempt should be made for external reduction of easily reducible hernias, if a hernia is present. PMID:26629305

Discreteness-induced concentration inversion in mesoscopic chemical systems.

PubMed

Ramaswamy, Rajesh; González-Segredo, Nélido; Sbalzarini, Ivo F; Grima, Ramon

2012-04-10

Molecular discreteness is apparent in small-volume chemical systems, such as biological cells, leading to stochastic kinetics. Here we present a theoretical framework to understand the effects of discreteness on the steady state of a monostable chemical reaction network. We consider independent realizations of the same chemical system in compartments of different volumes. Rate equations ignore molecular discreteness and predict the same average steady-state concentrations in all compartments. However, our theory predicts that the average steady state of the system varies with volume: if a species is more abundant than another for large volumes, then the reverse occurs for volumes below a critical value, leading to a concentration inversion effect. The addition of extrinsic noise increases the size of the critical volume. We theoretically predict the critical volumes and verify, by exact stochastic simulations, that rate equations are qualitatively incorrect in sub-critical volumes.

Morphological Features and Important Parameters of Large Optic Discs for Diagnosing Glaucoma

PubMed Central

Okimoto, Satoshi; Yamashita, Keiko; Shibata, Tetsuo; Kiuchi, Yoshiaki

2015-01-01

Purpose To compare the optic disc parameters of glaucomatous eyes to those of non-glaucomatous eyes with large discs. Methods We studied 225 consecutive eyes with large optic discs (>2.82 mm2): 91 eyes with glaucoma and 134 eyes without glaucoma. An eye was diagnosed with glaucoma when visual field defects were detected by the Humphrey Field Analyzer. All of the Heidelberg Retina Tomograph II (HRT II) parameters were compared between the non-glaucomatous and glaucomatous eyes. A logistic regression analysis of the HRT II parameters was used to establish a new formula for diagnosing glaucoma, and the sensitivity and specificity of the Moorfields Regression Analysis (MRA) was compared to the findings made by our analyses. Results The mean disc area was 3.44±0.50 mm2 in the non-glaucomatous group and 3.40±0.52 mm2 in the glaucoma group. The cup area, cup volume, cup-to-disc area ratio, linear cup/disc ratio, mean cup depth, and the maximum cup depth were significantly larger in glaucomatous eyes than in the non-glaucomatous eyes. The rim area, rim volume, cup shape measurement, mean retinal nerve fiber layer (RNFL) thickness, and RFNL cross-sectional area were significantly smaller in glaucomatous eyes than in non-glaucomatous eyes. The cup-to-disc area ratio, the height variation contour (HVC), and the RNFL cross-sectional area were important parameters for diagnosing the early stage glaucoma, and the cup-to-disc area ratio and cup volume were useful for diagnosing advanced stage glaucoma in eyes with a large optic disc. The new formula had higher sensitivity and specificity for diagnosing glaucoma than MRA. Conclusions The cup-to-disc area ratio, HVC, RNFL cross-sectional area, and cup volume were important parameters for diagnosing glaucoma in eyes with a large optic disc. The important disc parameters to diagnose glaucoma depend on the stage of glaucoma in patients with large discs. PMID:25798580

Phase II Study to Assess the Efficacy of Hypofractionated Stereotactic Radiotherapy in Patients With Large Cavernous Sinus Hemangiomas

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang Xin; Liu Xiaoxia; Mei Guanghai

Purpose: Cavernous sinus hemangioma is a rare vascular tumor. The direct microsurgical approach usually results in massive hemorrhage. Although radiosurgery plays an important role in managing cavernous sinus hemangiomas as a treatment alternative to microsurgery, the potential for increased toxicity with single-session treatment of large tumors is a concern. The purpose of this study was to assess the efficacy of hypofractionated stereotactic radiotherapy in patients with large cavernous sinus hemangiomas. Methods: Fourteen patients with large (volume >20 cm{sup 3}) cavernous sinus hemangiomas were enrolled in a prospective Phase II study between December 2007 and December 2010. The hypofractionated stereotactic radiotherapymore » dose was 21 Gy delivered in 3 fractions. Results: After a mean follow-up of 15 months (range, 6-36 months), the magnetic resonance images showed a mean of 77% tumor volume reduction (range, 44-99%). Among the 6 patients with cranial nerve impairments before hypofractionated stereotactic radiotherapy, 1 achieved symptomatic complete resolution and 5 had improvement. No radiotherapy-related complications were observed during follow-up. Conclusion: Our current experience, though preliminary, substantiates the role of hypofractionated stereotactic radiotherapy for large cavernous sinus hemangiomas. Although a longer and more extensive follow-up is needed, hypofractionated stereotactic radiotherapy of 21 Gy delivered in 3 fractions is effective in reducing the tumor volume without causing any new deficits and can be considered as a treatment modality for large cavernous sinus hemangiomas.« less

Feasibility and Acute Toxicity of Hypofractionated Radiation in Large-breasted Patients

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dorn, Paige L., E-mail: pdorn@radonc.uchicago.edu; Corbin, Kimberly S.; Al-Hallaq, Hania

Purpose: To determine the feasibility of and acute toxicity associated with hypofractionated whole breast radiation (HypoRT) after breast-conserving surgery in patients excluded from or underrepresented in randomized trials comparing HypoRT with conventional fractionation schedules. Methods and Materials: A review was conducted of all patients consecutively treated with HypoRT at University of Chicago. All patients were treated to 42.56 Gy in 2.66 Gy daily fractions in either the prone or supine position. Planning was performed in most cases using wedges and large segments or a 'field-in-field' technique. Breast volume was estimated using volumetric measurements of the planning target volume (PTV). Dosimetricmore » parameters of heterogeneity (V105, V107, V110, and maximum dose) were recorded for each treatment plan. Acute toxicity was scored for each treated breast. Results: Between 2006 and 2010, 78 patients were treated to 80 breasts using HypoRT. Most women were overweight or obese (78.7%), with a median body mass index of 29.2 kg/m{sup 2}. Median breast volume was 1,351 mL. Of the 80 treated breasts, the maximum acute skin toxicity was mild erythema or hyperpigmentation in 70.0% (56/80), dry desquamation in 21.25% (17/80), and focal moist desquamation in 8.75% (7/80). Maximum acute toxicity occurred after the completion of radiation in 31.9% of patients. Separation >25 cm was not associated with increased toxicity. Breast volume was the only patient factor significantly associated with moist desquamation on multivariable analysis (p = 0.01). Patients with breast volume >2,500 mL experienced focal moist desquamation in 27.2% of cases compared with 6.34% in patients with breast volume <2,500 mL (p = 0.03). Conclusions: HypoRT is feasible and safe in patients with separation >25 cm and in patients with large breast volume when employing modern planning and positioning techniques. We recommend counseling regarding expected increases in skin toxicity in women with a PTV volume >2,500 mL.« less

The effects of load history and design variables on performance limit states of circular bridge columns - volume 1.

DOT National Transportation Integrated Search

2015-01-01

This report is the first of three volumes and presents interpretation of all experimental and numerical data and recommendations. In : total, 30 large scale reinforced concrete columns tests were conducted under a variety of loading conditions. Using...

The plasticity of extracellular fluid homeostasis in insects.

PubMed

Beyenbach, Klaus W

2016-09-01

In chemistry, the ratio of all dissolved solutes to the solution's volume yields the osmotic concentration. The present Review uses this chemical perspective to examine how insects deal with challenges to extracellular fluid (ECF) volume, solute content and osmotic concentration (pressure). Solute/volume plots of the ECF (hemolymph) reveal that insects tolerate large changes in all three of these ECF variables. Challenges beyond those tolerances may be 'corrected' or 'compensated'. While a correction simply reverses the challenge, compensation accommodates the challenge with changes in the other two variables. Most insects osmoregulate by keeping ECF volume and osmotic concentration within a wide range of tolerance. Other insects osmoconform, allowing the ECF osmotic concentration to match the ambient osmotic concentration. Aphids are unique in handling solute and volume loads largely outside the ECF, in the lumen of the gut. This strategy may be related to the apparent absence of Malpighian tubules in aphids. Other insects can suspend ECF homeostasis altogether in order to survive extreme temperatures. Thus, ECF homeostasis in insects is highly dynamic and plastic, which may partly explain why insects remain the most successful class of animals in terms of both species number and biomass. © 2016. Published by The Company of Biologists Ltd.

"Tools For Analysis and Visualization of Large Time- Varying CFD Data Sets"

NASA Technical Reports Server (NTRS)

Wilhelms, Jane; vanGelder, Allen

1999-01-01

During the four years of this grant (including the one year extension), we have explored many aspects of the visualization of large CFD (Computational Fluid Dynamics) datasets. These have included new direct volume rendering approaches, hierarchical methods, volume decimation, error metrics, parallelization, hardware texture mapping, and methods for analyzing and comparing images. First, we implemented an extremely general direct volume rendering approach that can be used to render rectilinear, curvilinear, or tetrahedral grids, including overlapping multiple zone grids, and time-varying grids. Next, we developed techniques for associating the sample data with a k-d tree, a simple hierarchial data model to approximate samples in the regions covered by each node of the tree, and an error metric for the accuracy of the model. We also explored a new method for determining the accuracy of approximate models based on the light field method described at ACM SIGGRAPH (Association for Computing Machinery Special Interest Group on Computer Graphics) '96. In our initial implementation, we automatically image the volume from 32 approximately evenly distributed positions on the surface of an enclosing tessellated sphere. We then calculate differences between these images under different conditions of volume approximation or decimation.

Hyperbranched-polymer dispersed nanocomposite volume gratings for holography and diffractive optics

NASA Astrophysics Data System (ADS)

Tomita, Yasuo; Takeuchi, Shinsuke; Oyaizu, Satoko; Urano, Hiroshi; Fukamizu, Taka-aki; Nishimura, Naoya; Odoi, Keisuke

2016-10-01

We review our experimental investigations of photopolymerizable nanoparticle-polymer composites (NPCs) for holography and diffractive optics. Various types of hyperbranched polymer (HBP) were systhesized and used as transporting organic nanoparticles. These HBPs include hyperbranched poly(ethyl methacrylate) (HPEMA), hyperbranched polystyrene (HPS) and hyperbranched triazine/aromatic polymer units (HTA) whose refractive indices are 1.51, 1.61 and 1.82, respectively. Each HBP was dispersed in (meth)acrylate monomer whose refractive index was so chosen that a refractive index difference between HBP and the formed polymer was large. Such monomer-HBP syrup was mixed with a titanocene photoinitiator for volume holographic recording in the green. We used a two-beam interference setup to write an unslanted transmission volume grating at grating spacing of 1 μm and at a wavelength of 532 nm. It is shown that NPC volume gratings with the saturated refractive index modulation amplitudes as large as 0.008, 0.004 and 0.02 can be recorded in NPCs incorporated with HPEMA, HPS and HTA at their optimum concentrations of 34, 34 and 25 vol.%, respectively. We show the usefulness of HBP-dispersed NPC volume gratings for holographic applications such as holographic data storage and diffractive optical devices.

High-Volume Repeaters of Self-Harm.

PubMed

Ness, Jennifer; Hawton, Keith; Bergen, Helen; Waters, Keith; Kapur, Navneet; Cooper, Jayne; Steeg, Sarah; Clarke, Martin

2016-11-01

Repetition of self-harm is common and is strongly associated with suicide. Despite this, there is limited research on high-volume repetition. To investigate individuals with high-volume repeat self-harm attendances to the emergency department (ED), including their patterns of attendance and mortality. Data from the Multicentre Study of Self-Harm in England were used. High-volume repetition was defined as ⩾15 attendances within 4 years. An attendance timeline was constructed for each high-volume repeater (HVR) and the different patterns of attendance were explored using an executive sorting task and hierarchical cluster analysis. A small proportion of self-harm patients are HVRs (0.6%) but they account for a large percentage of self-harm attendances (10%). In this study, the new methodological approach resulted in three types of attendance patterns. All of the HVRs had clusters of attendance and a greater proportion died from external causes compared with non-HVRs. The approach used in this study offers a new method for investigating this problem that could have both clinical and research benefits. The need for early intervention is highlighted by the large number of self-harm episodes per patient, the clustered nature of attendances, and the higher prevalence of death from external causes.

Cone Penetration Testing, a new approach to quantify coastal-deltaic land subsidence by peat consolidation

NASA Astrophysics Data System (ADS)

Koster, Kay; Erkens, Gilles; Zwanenburg, Cor

2016-04-01

It is undisputed that land subsidence threatens coastal-deltaic lowlands all over the world. Any loss of elevation (on top of sea level rise) increases flood risk in these lowlands, and differential subsidence may cause damage to infrastructure and constructions. Many of these settings embed substantial amounts of peat, which is, due to its mechanically weak organic composition, one of the main drivers of subsidence. Peat is very susceptible to volume reduction by loading and drainage induced consolidation, which dissipates pore water, resulting in a tighter packing of the organic components. Often, the current state of consolidation of peat embedded within coastal-deltaic subsidence hotspots (e.g. Venice lagoon, Mississippi delta, San Joaquin delta, Kalimantan peatlands), is somewhere between its initial (natural) and maximum compressed stage. Quantifying the current state regarding peat volume loss, is of utmost importance to predict potential (near) future subsidence when draining or loading an area. The processes of subsidence often afflict large areas (>103 km2), thus demanding large datasets to assess the current state of the subsurface. In contrast to data describing the vertical motions of the actual surface (geodesy, satellite imagery), subsurface information applicable for subsidence analysis are often lacking in subsiding deltas. This calls for new initiatives to bridge that gap. Here we introduce Cone Penetration Testing (CPT) to quantify the amount of volume loss peat layers embedded within the Holland coastal plain (the Netherlands) experienced. CPT measures soil mechanical strength, and hundreds of thousands of CPTs are conducted each year on all continents. We analyzed 28 coupled CPT-borehole observations, and found strong empirical relations between volume loss and increased peat mechanical strength. The peat lost between ~20 - 95% of its initial thickness by dissipation of excess pore water. An increase in 0.1 - 0.4 MPa of peat strength is accountable for 20 - 75 % of the volume loss, and 0.4 - 0.7 MPa for 75 - 95 % volume loss. This indicates that large amounts of volume by water dissipation has to be lost, before peat experiences a serious increase in strength, which subsequently continuous to increase with only small amount of volume loss. To demonstrate the robustness of our approach to the international field of land subsidence, we applied the obtained empirical relations to previously published CPT logs deriving from the peat-rich San Joaquin-Sacramento delta and the Kalimantan peatlands, and found volume losses that correspond with previously published results. Furthermore, we used the obtained results to predict maximum surface lowering for these areas by consolidation. In conclusion, these promising results and its worldwide popularity yielding large datasets, open the door for CPT as a generic method to contribute to quantifying the imminent threat of coastal-deltaic land subsidence.

Interstitial laser photocoagulation for benign thyroid nodules: time to treat large nodules.

PubMed

Amabile, Gerardo; Rotondi, Mario; Pirali, Barbara; Dionisio, Rosa; Agozzino, Lucio; Lanza, Michele; Buonanno, Luciano; Di Filippo, Bruno; Fonte, Rodolfo; Chiovato, Luca

2011-09-01

Interstitial laser photocoagulation (ILP) is a new therapeutic option for the ablation of non-functioning and hyper-functioning benign thyroid nodules. Amelioration of the ablation procedure currently allows treating large nodules. Aim of this study was to evaluate the therapeutic efficacy of ILP, performed according to a modified protocol of ablation, in patients with large functioning and non-functioning thyroid nodules and to identify the best parameters for predicting successful outcome in hyperthyroid patients. Fifty-one patients with non-functioning thyroid nodules (group 1) and 26 patients with hyperfunctioning thyroid nodules (group 2) were enrolled. All patients had a nodular volume ≥40 ml. Patients were addressed to 1-3 cycles of ILP. A cycle consisted of three ILP sessions, each lasting 5-10 minutes repeated at an interval of 1 month. After each cycle of ILP patients underwent thyroid evaluation. A nodule volume reduction, expressed as percentage of the basal volume, significantly occurred in both groups (F = 190.4; P < 0.0001 for group 1 and F = 100.2; P < 0.0001 for group 2). Receiver-operator-characteristic (ROC) curves were constructed for: (i) percentage of volume reduction; (ii) difference in nodule volume; (iii) total amount of energy delivered expressed in Joule. ROC curves identified the percentage of volume reduction as the best parameter predicting a normalized serum TSH (area under the curve 0.962; P < 0.0001). Intraoperative complications consisted in: (i) mild pain occurring in five (6.5%) patients, (ii) vasovagal reaction in two (2.6%) patients, (iii) fever within 24 hours from ILP in five (6.5%) patients. No major complications including persistent pain, laringeal nerve dysfunction, hypoparathyroidism, pseudocystic transformation, and/or neck fascitis were observed. ILP represents a valid alternative to surgery also for large benign thyroid nodules, both in terms of nodule size reduction and cure of hyperthyroidism (87% of cured patients after the last ILP cycle). ILP should not be limited to patients refusing or being ineligible for surgery and/or radioiodine. Copyright © 2011 Wiley-Liss, Inc.

Hierarchical imaging: a new concept for targeted imaging of large volumes from cells to tissues.

PubMed

Wacker, Irene; Spomer, Waldemar; Hofmann, Andreas; Thaler, Marlene; Hillmer, Stefan; Gengenbach, Ulrich; Schröder, Rasmus R

2016-12-12

Imaging large volumes such as entire cells or small model organisms at nanoscale resolution seemed an unrealistic, rather tedious task so far. Now, technical advances have lead to several electron microscopy (EM) large volume imaging techniques. One is array tomography, where ribbons of ultrathin serial sections are deposited on solid substrates like silicon wafers or glass coverslips. To ensure reliable retrieval of multiple ribbons from the boat of a diamond knife we introduce a substrate holder with 7 axes of translation or rotation specifically designed for that purpose. With this device we are able to deposit hundreds of sections in an ordered way in an area of 22 × 22 mm, the size of a coverslip. Imaging such arrays in a standard wide field fluorescence microscope produces reconstructions with 200 nm lateral resolution and 100 nm (the section thickness) resolution in z. By hierarchical imaging cascades in the scanning electron microscope (SEM), using a new software platform, we can address volumes from single cells to complete organs. In our first example, a cell population isolated from zebrafish spleen, we characterize different cell types according to their organelle inventory by segmenting 3D reconstructions of complete cells imaged with nanoscale resolution. In addition, by screening large numbers of cells at decreased resolution we can define the percentage at which different cell types are present in our preparation. With the second example, the root tip of cress, we illustrate how combining information from intermediate resolution data with high resolution data from selected regions of interest can drastically reduce the amount of data that has to be recorded. By imaging only the interesting parts of a sample considerably less data need to be stored, handled and eventually analysed. Our custom-designed substrate holder allows reproducible generation of section libraries, which can then be imaged in a hierarchical way. We demonstrate, that EM volume data at different levels of resolution can yield comprehensive information, including statistics, morphology and organization of cells and tissue. We predict, that hierarchical imaging will be a first step in tackling the big data issue inevitably connected with volume EM.

Recurrent eruption and subsidence at the Platoro caldera complex, southeastern San Juan volcanic field, Colorado: New tales from old tuffs

USGS Publications Warehouse

Lipman, P.W.; Dungan, M.A.; Brown, L.L.; Deino, A.

1996-01-01

Reinterpretation of a voluminous regional ash-flow sheet (Masonic Park Tuff) as two separate tuff sheets of similar phenocryst-rich dacite erupted from separate source calderas has important implications for evolution of the multicyclic Platoro caldera complex and for caldera-forming processes generally. Masonic Park Tuff in central parts of the San Juan field, including the type area, was erupted from a concealed source at 28.6 Ma, but widespread tuff previously mapped as Masonic Park Tuff in the southeastern San Juan Mountains is the product of the youngest large-volume eruption of the Platoro caldera complex at 28.4 Ma. This large unit, newly named the "Chiquito Peak Tuff," is the last-erupted tuff of the Treasure Mountain Group, which consists of at least 20 separate ash-flow sheets of dacite to low-silica rhyolite erupted from the Platoro complex during a 1 m.y. interval (29.5-28.4 Ma). Two Treasure Mountain tuff sheets have volumes in excess of 1000 km3 each, and five more have volumes of 50-150 km3. The total volume of ash-flow tuff exceeds 2500 km3, and caldera-related lavas of dominantly andesitic composition make up 250-500 km3 more. A much greater volume of intermediate-composition magma must have solidified in subcaldera magma chambers. Most preserved features of the Platoro complex - including postcollapse asymmetrical trap-door resurgent uplift of the ponded intracaldera tuff and concurrent infilling by andesitic lava flows - postdate eruption of the Chiquito Peak Tuff. The numerous large-volume pre-Chiquito Peak ash-flow tuffs document multiple eruptions accompanied by recurrent subsidence; early-formed caldera walls nearly coincide with margins of the later Chiquito Peak collapse. Repeated syneruptive collapse at the Platoro complex requires cumulative subsidence of at least 10 km. The rapid regeneration of silicic magmas requires the sustained presence of an andesitic subcaldera magma reservoir, or its rapid replenishment, during the 1 m.y. life span of the Platoro complex. Either case implies large-scale stoping and assimilative recycling of the Tertiary section, including intracaldera tuffs.