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Strings at the bottom of the deformed conifoldApr 07 2005We present solutions of the equations of motion of macroscopic F and D strings extending along the non compact 4D sections of the conifold geometry and winding around the internal directions. The effect of the Goldstone modes associated with the position ... More

Cosmological Perturbations Generated in the Colliding Bubble Braneworld UniverseNov 12 2001Dec 18 2001We compute the cosmological perturbations generated in the colliding bubble braneworld universe in which bubbles filled with five-dimensional anti-de Sitter space (AdS5)expanding within a five dimensional de Sitter space (dS5) or Minkowski space (M5) ... More

Supersymmetric Rings in Field TheoryApr 25 2006Sep 26 2006We study the dynamics of BPS string-like objects obtained by lifting monopole and dyon solutions of N=2 Super-Yang-Mills theory to five dimensions. We present exact traveling wave solutions which preserve half of the supersymmetries. Upon compactification ... More

Cosmic Superstrings Stabilized by FermionsDec 05 2005We show that there exist massive perturbative states of the ten dimensional Green-Schwarz closed superstring that are stabilized against collapse due to presence of fermionic zero modes on its worldsheet. The excited fermionic degrees of freedom backreact ... More

The Global Structure of the Colliding Bubble Braneworld UniverseOct 20 2002We comment on the global structure of the spacetime that results from the collision of two bubbles filled with AdS space produced from the decay of a false vacuum through quantum tunnelling.

Observable effects of anisotropic bubble nucleationMar 02 2010Jun 02 2010Our universe may have formed via bubble nucleation in an eternally-inflating background. Furthermore, the background may have a compact dimension--the modulus of which tunnels out of a metastable minimum during bubble nucleation--which subsequently grows ... More

High Energy Cosmic Rays from NeutrinosFeb 18 1999Apr 03 2000We discuss recent models in which neutrinos, which are assumed to have mass in the eV range, originate the highest energy cosmic rays by interaction with the enhanced density in the galactic halo of the relic cosmic neutrino background. We make an analytical ... More

Limits on Topological Defect Neutrino fluxes from Horizontal Air Shower measurementsNov 30 1996We obtain the horizontal air shower rate from the (EeV) high energy neutrino flux predicted in some topological defect scenarios as the source for the highest energy cosmic rays. Emphasis is made on the different character of the events depending on the ... More

Fundamental Plasmid Strings and Black RingsDec 05 2007Jan 09 2008We construct excited states of fundamental strings that admit a semiclassical description as rotating circular loops of string. We identify them with the supergravity solutions for rotating dipole rings. The identification involves a precise match of ... More

Cosmic D-strings as Axionic D-term StringsMay 19 2005Oct 28 2005In this work we derive non-singular BPS string solutions from an action that captures the essential features of a D-brane-anti-D-brane system compactified to four dimensions. The model we consider is a supersymmetric abelian Higgs model with a D-term ... More

On Semiclassical Limits of String StatesJun 05 2007We explore the relation between classical and quantum states in both open and closed (super)strings discussing the relevance of coherent states as a semiclassical approximation. For the closed string sector a gauge-fixing of the residual world-sheet rigid ... More

When do colliding bubbles produce an expanding universe?Jun 17 2003Jul 08 2003It is intriguing to consider the possibility that the Big Bang of the standard (3+1) dimensional cosmology originated from the collision of two branes within a higher dimensional spacetime, leading to the production of a large amount of entropy. In this ... More

Topological Defects from the MultiverseJan 22 2015Many theories of the early universe predict the existence of a multiverse where bubbles continuously nucleate giving rise to observers in their interior. In this paper, we point out that topological defects of several dimensionalities will also be produced ... More

Transdimensional Tunneling in the MultiverseDec 21 2009May 06 2010Topology-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 ($dS_6$), a number of $dS_4 \times S_2$ ... More

Dynamics of superconducting strings with chiral currentsApr 28 2000Mar 07 2001We rederive, using an elementary formalism, the general solution to the equations of motion for a superconducting string with a chiral (null) neutral current, earlier obtained by Carter and Peter. We apply this solution to show that the motion of such ... More

Gravitational backreaction simulations of simple cosmic string loopsMar 14 2019We present the results of computational gravitational backreaction on simple models of cosmic string loops. These results give us insight into the general behavior of cusps and kinks on loops, in addition to other features of evolution. Kinks are rounded ... More

Bubbles of Nothing and Supersymmetric CompactificationsJun 09 2016We investigate the non-perturbative stability of supersymmetric compactifications with respect to decay via a bubble of nothing. We show examples where this kind of instability is not prohibited by the spin structure, i.e., periodicity of fermions about ... More

Supermassive Cosmic String CompactificationsDec 19 2013The space-time dimensions transverse to a static straight cosmic string with a sufficiently large tension (supermassive cosmic strings) are compact and typically have a singularity at a finite distance form the core. In this paper, we discuss how the ... More

Cosmic string loop shapesAug 11 2015We analyze the shapes of cosmic string loops found in large-scale simulations of an expanding-universe string network. The simulation does not include gravitational back reaction, but we model that process by smoothing the loop using Lorentzian convolution. ... More

Quantum Tunneling in Flux CompactificationsApr 20 2009Nov 05 2009We identify instantons representing vacuum decay in a 6-dimensional toy model for string theory flux compactifications, with the two extra dimensions compactified on a sphere. We evaluate the instanton action for tunneling between different flux vacua, ... More

Supersymmetry and Stability of Flux VacuaNov 03 2005May 01 2006We describe a modified KKLT mechanism of moduli stabilization in a supersymmetric Minkowski vacuum state. In this mechanism, supersymmetry ensures vacuum stability and positivity of the mass matrix for the dilaton, complex structure, and the volume modulus. ... More

Skyrme BranesSep 04 2008We obtain static selfgravitating solitonic 3-brane solutions in the Einstein-Skyrme model in 7D. These solitons correspond to a smooth version of the previously discussed cosmic p-brane solutions. We show how the energy momentum tensor of the Skyrme field ... More

Gravitational back-reaction near cosmic string kinks and cuspsAug 24 2018Aug 31 2018We find the leading-order effect of gravitational back-reaction on cosmic strings for points near kinks and cusps. Near a kink, the effect diverges as the inverse cube root of the distance to the kink, and acts in a direction transverse to the worldsheet. ... More

New limits on cosmic strings from gravitational wave observationSep 07 2017Sep 11 2017We combine new analysis of the stochastic gravitational wave background to be expected from cosmic strings with the latest pulsar timing array (PTA) limits to give an upper bound on the energy scale of the possible cosmic string network, $G\mu < 1.5\times ... More

Racetrack Potentials and the de Sitter Swampland ConjecturesNov 13 2018Jan 15 2019We show that one can find de Sitter critical points (saddle points) in models of flux compactification of Type IIB String Theory without any uplifting terms and in the presence of several moduli. We demonstrate this by giving explicit examples following ... More

Cosmic string formation by flux trappingJun 11 2007Aug 01 2007We study the formation of cosmic strings by confining a stochastic magnetic field into flux tubes in a numerical simulation. We use overdamped evolution in a potential that is minimized when the flux through each face in the simulation lattice is a multiple ... More

Quantum tunneling of superconducting string currentsFeb 13 2002We investigate the decay of current on a superconducting cosmic string through quantum tunneling. We construct the instanton describing tunneling in a simple bosonic string model, and estimate the decay rate. The tunneling rate vanishes in the limit of ... More

Large Scale Power Suppression in a Multifield LandscapeMar 25 2015Sep 30 2015Power suppression of the cosmic microwave background on the largest observable scales could provide valuable clues about the particle physics underlying inflation. Here we consider the prospect of power suppression in the context of the multifield landscape. ... More

Accidental Inflation in the LandscapeSep 04 2012We study some aspects of fine tuning in inflationary scenarios within string theory flux compactifications and, in particular, in models of accidental inflation. We investigate the possibility that the apparent fine-tuning of the low energy parameters ... More

Kahler Moduli Inflation RevisitedJun 19 2009We perform a detailed numerical analysis of inflationary solutions in Kahler moduli of type IIB flux compactifications. We show that there are inflationary solutions even when all the fields play an important role in the overall shape of the scalar potential. ... More

Effects on the CMB from Compactification Before InflationJan 06 2017Apr 24 2017Many 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 ... More

Racetrack InflationJun 24 2004Dec 16 2004We develop a model of eternal topological inflation using a racetrack potential within the context of type IIB string theory with KKLT volume stabilization. The inflaton field is the imaginary part of the K\"ahler structure modulus, which is an axion-like ... More

Inflating in a Better RacetrackMar 16 2006May 23 2006We present a new version of our racetrack inflation scenario which, unlike our original proposal, is based on an explicit compactification of type IIB string theory: the Calabi-Yau manifold P^4_[1,1,1,6,9]. The axion-dilaton and all complex structure ... More

Klein-Gordon equation from Maxwell-Lorentz dynamicsJan 27 2012Feb 19 2012We consider Maxwell-Lorentz dynamics: that is to say, Newton's law under the action of a Lorentz's force which obeys the Maxwell equations. A natural class of solutions are those given by the Lagrangian submanifolds of the phase space when it is endowed ... More

Two-cycles in spin systems: multi-state Ising-type ferromagnetsAug 04 2004Hamiltonians for general multi-state spin-glass systems with Ising symmetry are derived for both sequential and synchronous updating of the spins. The possibly different behaviour caused by the way of updating is studied in detail for the (anti)-ferromagnetic ... More

A semilattice structure for the set of numerical semigroups with fixed Frobenius numberMay 20 2011We present a procedure to enumerate the whole set of numerical semigroups with a given Frobenius number F, S(F). The methodology is based on the construction of a partition of S(F) by a congruence relation. We identify exactly one irreducible and one ... More

The tree of irreducible numerical semigroups with fixed Frobenius numberMay 11 2011In this paper we present a procedure to build the set of irreducible numerical semigroups with a fixed Frobenius number. The construction gives us a rooted tree structure for this set. Furthermore, by using the notion of Kunz-coordinates vector we translate ... More

The set of numerical semigroups of a given genusJun 08 2011In this paper we present a new approach to construct the set of numerical semigroups with a fixed genus. Our methodology is based on the construction of the set of numerical semigroups with fixed Frobenius number and genus. An equivalence relation is ... More

The synchronous BEG neural network with variable dilutionMay 12 2005The thermodynamic and retrieval properties of the Blume-Emery-Griffiths neural network with synchronous updating and variable dilution are studied using replica mean-field theory. Several forms of dilution are allowed by pruning the different types of ... More

m-irreducible numerical semigroupsJun 17 2010In this paper we introduce the notion of m-irreducibility that extends the standard concept of irreducibility of a numerical semigroup when the multiplicity is fixed. We analyze the structure of the set of m-irreducible numerical semigroups, we give some ... More

Redshift for massive particlesJun 22 2018On each FRW metric, there exist a redshift for massive particles, analogous to that of photons, but depending on the mass. This is a simple consequence of the fundamental laws of Classical Mechanics.

Time in classical and quantum mechanicsJul 12 2017Sep 20 2018In this article we study the nature of time in Mechanics. The fundamental principle, according to which a mechanical system evolves governed by a second order differential equation, implies the existence of an absolute time-duration in the sense of Newton. ... More

On the quantization of mechanical systemsJan 16 2017Mar 27 2017We present a canonical way of assigning to each magnitude of a classical mechanical system a differential operator in the configuration space, thus rigorously establishing the Correspondence Principle for such systems. Here we show how each classical ... More

On the absolute value of the air-fluorescence yieldJan 17 2014The absolute value of the air-fluorescence yield is a key parameter for the energy reconstruction of extensive air showers registered by fluorescence telescopes. In previous publications, we reported a detailed Monte Carlo simulation of the air-fluorescence ... More

Average value of available measurements of the absolute air-fluorescence yieldMar 10 2011The air-fluorescence yield is a key parameter for determining the energy scale of ultra-high-energy cosmic rays detected by fluorescence telescopes. A compilation of the available measurements of the absolute air-fluorescence yield normalized to its value ... More

Improved model for the analysis of air fluorescence induced by electronsDec 20 2007Jul 24 2008A model recently proposed for the calculation of air-fluorescence yield excited by electrons is revisited. Improved energy distributions of secondary electrons and a more realistic Monte Carlo simulation including some additional processes have allowed ... More

Multiplicative versus additive noise in multi-state neural networksMar 01 2004The effects of a variable amount of random dilution of the synaptic couplings in Q-Ising multi-state neural networks with Hebbian learning are examined. A fraction of the couplings is explicitly allowed to be anti-Hebbian. Random dilution represents the ... More

A note on the foundations of mechanicsApr 04 2014This short note is intended to review the foundations of mechanics, trying to present them with the greatest mathematical and conceptual clarity. It was attempted to remove most of inessential, even parasitic issues, which can hide the true nature of ... More

Novel Gamma-Ray Signatures of PeV-Scale Dark MatterDec 07 2017The gamma-ray annihilation and decay products of very heavy dark matter particles can undergo attenuation through pair production, leading to the development of electromagnetic cascades. This has a significant impact not only on the spectral shape of ... More

A note on the quantization of tensor fields and quantization of mechanical systemsJan 16 2018Mar 16 2018This article continues and completes our previous work J. Phys. Commun. 2 (2018) 025007. We present two methods of quantization associated with a linear connection given on a differentiable manifold. One of these is that presented in the mentioned article. ... More

Comparison of available measurements of the absolute air-fluorescence yield and determination of its global average valueApr 05 2011Experimental results of the absolute air-fluorescence yield are given very often in different units (photons/MeV or photons/m) and for different wavelength intervals. In this work we present a comparison of available results normalized to its value in ... More

On the foundation of MechanicsNov 27 2014Dec 09 2014This note is an extended version of "A note on the foundations of Mechanics", arXiv: 1404.1321 [math-ph]. A presentation of its contents was given in a talk in memorial homage to the professor Juan B. Sancho Guimer\'a. For this reason, it was written ... More

The signal-to-noise analysis of the Little-Hopfield model revisitedJul 21 2003Using the generating functional analysis an exact recursion relation is derived for the time evolution of the effective local field of the fully connected Little-Hopfield model. It is shown that, by leaving out the feedback correlations arising from earlier ... More

Primary spectrum of $\mathcal{C}^\infty(M)$ and jets theoryOct 31 2016We consider, for each smooth manifold $M$, the set $\mathbb{M}$ comprised by all the primary ideals of $\mathcal{C}^\infty(M)$ which are closed and whose radical is maximal. The classical Lie theory of jets (jets of submanifolds) must be extended to $\mathbb{M}$ ... More

Newton's Second Law in Field TheoryNov 13 2018In this article we present a natural generalization of Newton's Second Law valid in field theory, i.e., when the parameterized curves are replaced by parameterized submanifolds of higher dimension. For it we introduce what we have called the geodesic ... More

Comparison of available measurements of the absolute fluorescence yieldApr 22 2010May 20 2010The uncertainty in the absolute value of the fluorescence yield is still one of the main contributions to the total error in the reconstruction of the primary energy of ultra-energetic air showers using the fluorescence technique. A significant number ... More

Bandwidth of the product of paths of the same lengthSep 14 2012In this note we give a numerical expression for the bandwidth $bw(P_{n}^{d})$ of the $d$-product of a path with $n$ edges, $P_{n}^{d}$. We prove that this bandwidth is given by the sum of certain multinomial coefficients. We also show that $bw(P_{n}^{d})$ ... More

Longwave radiative analysis of cloudy scattering atmospheres using a Net Exchange FormulationFeb 22 2019The Net Exchange Formulation (NEF) is an alternative to the usual radiative transfer equation. It was proposed in 1967 by Green [1] for atmospheric sciences and by Hottel [2] for engineering sciences. Until now, the NEF has been used only in a very few ... More

Nonlinear silicon photonics analyzed with the moment methodOct 02 2014We apply the moment method to nonlinear pulse propagation in silicon waveguides in the presence of two-photon absorption, free-carrier dispersion and free-carrier absorption. The evolution equations for pulse energy, temporal position, duration, frequency ... More

Magnetocrystalline Anisotropy of Fe-based $L1_0$ Alloys: Validity of Approximate Methods to Treat the Spin-Orbit InteractionNov 29 2018First-principles calculations are used to gauge different levels of approximation to calculate the magnetocrystalline anisotropy energies (MAE) of five $L1_0$ FeMe alloys (Me=Co, Cu, Pd, Pt, Au). We find that a second-order perturbation (2PT) treatment ... More

Modeling crosstalk in silicon photomultipliersFeb 06 2013Optical crosstalk seriously limits the photon-counting resolution of silicon photomultipliers. In this work, realistic analytical models to describe the crosstalk effects on the response of these photodetectors are presented and compared with experimental ... More

The yield of air fluorescence induced by electronsApr 24 2006Jun 19 2006The fluorescence yield for dry air and pure nitrogen excited by electrons is calculated using a combination of well-established molecular properties and experimental data of the involved cross sections. Particular attention has been paid to the role of ... More

Rank-Metric Codes and Zeta FunctionsMay 23 2017We define the rank-metric zeta function of a code as a generating function of its normalized $q$-binomial moments. We show that, as in the Hamming case, the zeta function gives a generating function for the weight enumerators of rank-metric codes. We ... More

Energy splitting of image states induced by the surface potential corrugation of InAs(111)AJun 22 2015By means of scanning tunneling spectroscopy (STS) we study the electronic structure of the III-V semiconductor surface InAs(111)A in the field emission regime (above the vacuum level). At high sample bias voltages (approaching +10 V), a series of well ... More

Electron energy loss and induced photon emission in photonic crystalsOct 14 2002The interaction of a fast electron with a photonic crystal is investigated by solving the Maxwell equations exactly for the external field provided by the electron in the presence of the crystal. The energy loss is obtained from the retarding force exerted ... More

The Blume-Emery-Griffiths neural network: dynamics for arbitrary temperatureApr 24 2003The parallel dynamics of the fully connected Blume-Emery-Griffiths neural network model is studied for arbitrary temperature. By employing a probabilistic signal-to-noise approach, a recursive scheme is found determining the time evolution of the distribution ... More

A boundary-based net-exchange Monte Carlo method for absorbing and scattering thick mediaFeb 21 2019A boundary-based net-exchange Monte Carlo method was introduced in [1] that allows to bypass the difficulties encountered by standard Monte Carlo algorithms in the limit of optically thick absorption (and/or for quasi-isothermal configurations). With ... More

Structure of second-order symmetric Lorentzian manifoldsJan 28 2011Jul 06 2011Second-order symmetric Lorentzian spaces, that is to say, Lorentzian manifolds with vanishing second derivative of the curvature tensor R, are characterized by several geometric properties, and explicitly presented. Locally, they are a product M=M_1 x ... More

A Semidefinite Programming approach for minimizing ordered weighted averages of rational functionsJun 13 2011Jun 28 2011This paper considers the problem of minimizing the ordered weighted average (or ordered median) function of finitely many rational functions over compact semi-algebraic sets. Ordered weighted averages of rational functions are not, in general, neither ... More

Second-order symmetric Lorentzian manifolds II: structure and global propertiesJan 18 2011We give a summary of recent results on the explicit local form of the second-order symmetric Lorentzian manifolds in arbitrary dimension, and its global version. These spacetimes turn out to be essentially a specific subclass of plane waves.

Nuclear Dependence of Charm ProductionFeb 02 2009Oct 08 2009With data taken by SELEX, which accumulated data during the 1996-1997 fixed target run at Fermilab, we study the production of charmed hadrons on copper and carbon targets with Sigma-, p, pi-, and pi+ beams. Parameterizing the production cross section ... More

Electron iduced light emission in photonic crystalsOct 14 2002The interaction of a fast electron with a photonic crystal is studied by solving the Maxwell equations exactly for the external field provided by the electron in the presence of the crystal. The polarization currents and charges produced by the passage ... More

Complete classification of second-order symmetric spacetimesJan 20 2010As a difference with the positive-definite Riemannian case, in the Lorentzian case there exists proper second-order symmetric spacetimes, i.e., those with vanishing second covariant derivative of the Riemannian tensor ($R_{\lambda\mu\nu\rho;\alpha;\beta}=0$) ... More

Parity-odd multipoles, magnetic charges and chirality in haematite (alfa-Fe2O3)Oct 08 2010Nov 02 2010Collinear and canted magnetic motifs in haematite were investigated by Kokubun et al. (2008) using x-ray Bragg diffraction magnified at the iron K-edge, and analyses of observations led to various potentially interesting conclusions. We demonstrate that ... More

Stable states of systems of bistable magnetostrictive wires against applied field, applied stress and spatial geometryOct 03 2006Long-range magnetostatic interaction between wires strongly depends on their spatial position. This interaction, combined with applied tensile stress, influences the hysteresis loop of the system of wires through the stress dependence of their coercive ... More

On metastable configurations of small-world networksOct 18 2005We calculate the number of metastable configurations of Ising small-world networks which are constructed upon superimposing sparse Poisson random graphs onto a one-dimensional chain. Our solution is based on replicated transfer-matrix techniques. We examine ... More

Parallel dynamics of the fully connected Blume-Emery-Griffiths neural networkJun 28 2002The parallel dynamics of the fully connected Blume-Emery-Griffiths neural network model is studied at zero temperature for arbitrary using a probabilistic approach. A recursive scheme is found determining the complete time evolution of the order parameters, ... More

Observable effects of Interplanetary Coronal Mass Ejections on ground level neutron monitor counting ratesFeb 11 2013In this work, non-recurrent Forbush decreases (FDs) triggered by the passage of shock-driven interplanetary coronal mass ejections (ICMEs) have been analyzed. Fifty-nine ICMEs have been studied but only the 25% of them were associated to a FD. We find ... More

A constraint-based approach to granular dispersion rheologyJul 30 2018We present a phenomenological model for granular suspension rheology in which particle interactions enter as constraints to relative particle motion. By considering constraints that are formed and released by stress respectively, we derive a range of ... More

Efficiency of Brownian MotorsMar 25 1998The efficiency of different types of Brownian motors is calculated analytically and numerically. We find that motors based on flashing ratchets present a low efficiency and an unavoidable entropy production. On the other hand, a certain class of motors ... More

Study of the pressure effects in TiOCl by ab initio calculationsMay 08 2009Electronic structure calculations on the low dimensional spin-1/2 compound TiOCl were performed at several pressures in the orthorhombic phase, finding that the structure is quasi-one-dimensional. The Ti3+ (d1) ions have one t2g orbital occupied (dyz) ... More

Pressure-induced metal-insulator transition in MgV_2O_4Jul 25 2007On the basis of experimental thermoelectric power results and ab initio calculations, we propose that a metal-insulator transition takes place at high pressure (approximately 6 GPa) in MgV_2O_4.

The Air-Fluorescence YieldJul 30 2008Detection of the air-fluorescence radiation induced by the charged particles of extensive air showers is a well-established technique for the study of ultra-high energy cosmic rays. Fluorescence telescopes provide a nearly calorimetric measure of the ... More

Diffusion of Hydrogen in Pd Assisted by Inelastic Ballistic Hot ElectronsMar 15 2012Sykes {\it et al.} [Proc. Natl. Acad. Sci. {\bf 102}, 17907 (2005)] have reported how electrons injected from a scanning tunneling microscope modify the diffusion rates of H buried beneath Pd(111). A key point in that experiment is the symmetry between ... More

Bayesian nonparametric comorbidity analysis of psychiatric disordersJan 29 2014The analysis of comorbidity is an open and complex research field in the branch of psychiatry, where clinical experience and several studies suggest that the relation among the psychiatric disorders may have etiological and treatment implications. In ... More

Magnetic ordering in GdNi2B2C revisited by resonant x-ray scattering: evidence for the double-q modelJun 21 2013Recent theoretical efforts aimed at understanding the nature of antiferromagnetic ordering in GdNi2B2C predicted double-q ordering. Here we employ resonant elastic x-ray scattering to test this theory against the formerly proposed, single-q ordering scenario. ... More

Optimal Carbon Taxes for Emissions Targets in the Electricity SectorApr 17 2018The most dangerous effects of anthropogenic climate change can be mitigated by using emissions taxes or other regulatory interventions to reduce greenhouse gas (GHG) emissions. This paper takes a regulatory viewpoint and describes the Weighted Sum Bisection ... More

Convergence issues in derivatives of Monte Carlo null-collision integral formulations: a solutionMar 15 2019When a Monte Carlo algorithm is used to evaluate a physical observable A, it is possible to slightly modify the algorithm so that it evaluates simultaneously A and the derivatives $\partial$ $\varsigma$ A of A with respect to each problem-parameter $\varsigma$. ... More

Efficient and Effective Tail Latency Minimization in Multi-Stage Retrieval SystemsApr 13 2017Apr 20 2017Scalable web search systems typically employ multi-stage retrieval architectures, where an initial stage generates a set of candidate documents that are then pruned and re-ranked. Since subsequent stages typically exploit a multitude of features of varying ... More

The Fabra-ROA Baker-Nunn Camera at Observatori Astronòmic del Montsec: a wide-field imaging facility for exoplanet transit detectionDec 04 2009A number of Baker-Nunn Camera (BNC) were manufactured by Smithsonian Institution during the 60s as optical tracking systems for artificial satellites with optimal optical and mechanical specifications. One of them was installed at the Real Instituto y ... More

An Overview of the Rotational Behavior of Metal--Poor StarsSep 24 2010The present paper describes the behavior of the rotational velocity in metal--poor stars ([Fe/H]<-0.5 dex) in different evolutionary stages, based on Vsini values from the literature. Our sample is comprised of stars in the field and some Galactic globular ... More

Characterisation of the Galactic thin disc with Corot targetsJan 01 2013We use kinematical and chemical properties of 754 Corot stars to characterise the stellar populations of the Milky Way disc in three beams close the Galactic plane. From the atmospheric parameters derived in Gazzano et al. (2010) with the Matisse algorithm, ... More

Preliminary optical design of PANIC, a wide-field infrared camera for CAHAJul 25 2008In this paper, we present the preliminary optical design of PANIC (PAnoramic Near Infrared camera for Calar Alto), a wide-field infrared imager for the Calar Alto 2.2 m telescope. The camera optical design is a folded single optical train that images ... More

On the energy deposition by electrons in air and the accurate determination of the air-fluorescence yieldJul 12 2012The uncertainty in the absolute value of the air-fluorescence yield still puts a severe limit on the accuracy in the primary energy of ultra-high-energy cosmic rays. The precise measurement of this parameter in laboratory is in turn conditioned by a careful ... More

Time-of-flight secondary ion mass spectrometry-based molecular distribution distinguishing healthy and osteoarthritic human cartilageJun 17 2013Osteoarthritis (OA) is a pathology that ultimately causes joint destruction. The cartilage is one of the principal affected tissues. Alterations in the lipid mediators and an imbalance in the metabolism of cells that form the cartilage (chondrocytes) ... More

Extensions of linear regression models based on set arithmetic for interval dataOct 22 2012Extensions of previous linear regression models for interval data are presented. A more flexible simple linear model is formalized. The new model may express cross-relationships between mid-points and spreads of the interval data in a unique equation ... More

Homopolar bond formation in ZnV$_2$O$_4$ close to a metal-insulator transitionMay 12 2008Electronic structure calculations for spinel vanadate ZnV$_2$O$_4$ show that partial electronic delocalization in this system leads to structural instabilities. These are a consequence of the proximity to the itinerant-electron boundary, not being related ... More

Hard X-ray Emission from Cassiopeia A SNRJul 07 1997Jul 21 1997We report the results of extracting the hard X-ray continuum spectrum of Cas A SNR from RXTE/PCA Target of Opportunity (TOO) observations and CGRO/OSSE observations. The data can rule out the single thermal bremsstrahlung model for Cas A continuum between ... More

Spicule emission profiles observed in \ion{He}{i} 10830 ÅJul 30 2007Off-the-limb observations with high spatial and spectral resolution will help us understand the physical properties of spicules in the solar chromosphere Spectropolarimetric observations of spicules in the \ion{He}{i} 10830 \AA\ multiplet were obtained ... More

Topologically protected entangled photonic statesFeb 26 2019Entangled multiphoton states lie at the heart of quantum information, computing, and communications. In recent years, topology has risen as a new avenue to robustly transport quantum states in the presence of fabrication defects, disorder and other noise ... More