Results for "J. Alves"

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Size distribution of circumstellar disks in the Trapezium clusterJun 24 2005In this paper we present results on the size distribution of circumstellar disks in the Trapezium cluster as measured from HST/WFPC2 data. Direct diameter measurements of a sample of 135 bright proplyds and 14 silhouettes disks suggest that there is a ... More
Backward volume contraction for endomorphisms with eventual volume expansionOct 21 2009We consider smooth maps on compact Riemannian manifolds. We prove that under some mild condition of eventual volume expansion Lebesgue almost everywhere we have uniform backward volume contraction on every pre-orbit of Lebesgue almost every point.
2MASS wide field extinction maps: II. The Ophiuchus and the Lupus cloud complexeSep 22 2008We present an extinction map of a ~1,700 deg sq region that encloses the Ophiuchus, the Lupus, and the Pipe dark complexes using 42 million stars from the Two Micron All Sky Survey (2MASS) point source catalog. The use of a robust and optimal near-infrared ... More
Transitions in a Probabilistic Interface Growth ModelApr 04 2011May 08 2011We study a generalization of the Wolf-Villain (WV) interface growth model based on a probabilistic growth rule. In the WV model, particles are randomly deposited onto a substrate and subsequently move to a position nearby where the binding is strongest. ... More
Effects of a kinetic barrier on limited-mobility interface growth modelsFeb 08 2019Feb 13 2019The role played by a kinetic barrier originated by out-of-plane step edge diffusion, introduced in [Leal \textit{et al.}, \href{}{J. Phys. Condens. Matter \textbf{23}, 292201 (2011)}], is investigated in the ... More
Event-based Electricity Metering: An Autonomous Method to Determine Transmission ThresholdsMar 06 2018This paper provides an in-depth analysis of the event-based metering strategy proposed by Simonov et al. This strategy is an alternative to the traditional periodic (time-based) metering where the power demand is averaged in fixed time periods (e.g. every ... More
A Throughput and Energy Efficiency Scheme for Unlicensed Massive Machine Type CommunicationsMay 04 2019In this paper the throughput and energy efficiency of an unlicensed machine type communications network is studied. If an outage event happens in the network, there is a possibility for packet retransmissions in order to obtain a lower error probability. ... More
The night-sky at the Calar Alto Observatory II: The sky at the near infraredSep 29 2008We present here the characterization of the night sky-brightness at the near-infrared, the telescope seeing, and the fraction of useful time at the Calar Alto observatory. For this study we have collected a large dataset comprising 7311 near-infrared ... More
Primordial Gravitational Waves in Running Vacuum CosmologiesApr 27 2015Nov 26 2016We investigate the cosmological production of gravitational waves in a nonsingular flat cosmology powered by a "running vacuum" energy density described by $\rho_{\Lambda}\equiv\rho_{\Lambda}(H)$, a phenomenological expression potentially linked with ... More
On special limits of the Mixed Painlevé P$_{\mathbf{III-V}}$ ModelApr 26 2019The paper discusses P$_{III-V}$ equation for special values of its parameters for which this equation reduces to P$_{III}$, I$_{12}$, as well as, to some special cases of I$_{38}$ and I$_{49}$ equations from the Ince's list of $50$ second order differential ... More
Average Error Probability in Wireless Sensor Networks with Imperfect Sensing and Communication for Different Decision RulesAug 10 2015Feb 16 2016This paper presents a framework to evaluate the probability that a decision error event occurs in wireless sensor networks, including sensing and communication errors. We consider a scenario where sensors need to identify whether a given event has occurred ... More
Fisher matrix forecasts for astrophysical tests of the stability of the fine-structure constantApr 27 2017We use Fisher Matrix analysis techniques to forecast the cosmological impact of astrophysical tests of the stability of the fine-structure constant to be carried out by the forthcoming ESPRESSO spectrograph at the VLT (due for commissioning in late 2017), ... More
Morphological transition between diffusion-limited and ballistic aggregation growth patternsApr 20 2005Mar 23 2006In this work, the transition between diffusion-limited and ballistic aggregation models was revisited using a model in which biased random walks simulate the particle trajectories. The bias is controlled by a parameter $\lambda$, which assumes the value ... More
Symmetries and hamiltonians of Ince's XXXVIII and XLIX equationsApr 29 2019We discuss symmetries of Hamiltonians of I$_{38}$ and I$_{49}$ equations that appear on Ince's list of fifty second-order differential equations with Painlev\'e property. This study is informed by structure of Weyl symmetries of Painlev\'e P$_{III}$ and ... More
A First Constraint on the Thick Disk Scale Length: Differential Radial Abundances in K Giants at Galactocentric Radii 4, 8, and 12 kpcJun 09 2011Jun 27 2011Based on high-resolution spectra obtained with the MIKE spectrograph on the Magellan telescopes we present detailed elemental abundances for 20 red giant stars in the outer Galactic disk, located at Galactocentric distances between 9 and 13 kpc. The outer ... More
The first chemical abundance analysis of K giants in the inner Galactic discApr 16 2010Jun 12 2010The elemental abundance structure of the Galactic disc has been extensively studied in the solar neighbourhood using long-lived stars such as F and G dwarfs or K and M giants. These are stars whose atmospheres preserve the chemical composition of their ... More
Unusual plastic deformation and damage features in Titanium: experimental tests and constitutive modelingMay 18 2015In this paper, we present an experimental study on plastic deformation and damage of polycrystalline pure Ti, as well as modeling of the observed behavior. From the mechanical characterization data, it can be concluded that the material displays anisotropy ... More
Orion Revisited - I. The massive cluster in front of the Orion Nebula ClusterSep 17 2012Sep 26 2012The aim of this work is to characterize the stellar population between Earth and the Orion A molecular cloud where the well known star formation benchmark Orion Nebula Cluster (ONC) is embedded. We use the denser regions the Orion A cloud to block optical ... More
Performances of a Newly High Sensitive Trilayer F/Cu/F GMI SensorJul 28 2007Oct 08 2007We have selected stress-annealed nanocrystalline Fe-based ribbons for ferromagnetic/copper/ferromagnetic sensors exhibiting high magneto-impedance ratio. Longitudinal magneto-impedance reaches 400% at 60 kHz and longitudinal magneto-resistance increases ... More
Abundance trends in the inner and outer Galactic diskJan 10 2012Based on high-resolution spectra obtained with the MIKE spectrograph on the Magellan telescopes we present detailed elemental abundances for 64 red giant stars in the inner and outer Galactic disk. For the inner disk sample (4-7 kpc from the Galactic ... More
Iterative reconstruction of SiPM light response functions in a square-shaped compact gamma cameraOct 09 2016Compact gamma cameras with a square-shaped monolithic scintillator crystal and an array of silicon photomultipliers (SiPMs) are actively being developed for applications in areas such as small animal imaging, cancer diagnostics and radiotracer guided ... More
Throughput Maximization in Multi-Hop Wireless Networks under Secrecy ConstraintApr 16 2015Dec 17 2015This paper analyzes the throughput of industrial communication networks under a secrecy constraint. The proposed scenario is composed by sensors that measure some relevant information of the plant that is first processed by aggregator node and then sent ... More
Effects of Relay Selection Strategies on the Spectral Efficiency of Wireless Systems with Half- and Full-duplex NodesJul 14 2015Jan 29 2017This work proposes an analytical framework to study how relay selection strategies perform in half- and full-duplex deployments by combining renewal theory and stochastic geometry. Specifically, we assume that the network nodes -- operating in either ... More
Solutions of Mixed Painlevé P$_{\mathbf{III-V}}$ ModelNov 01 2018We review the construction of the mixed Painlev\'e P$_{III-V}$ system in terms of a 4-boson integrable model and discuss its symmetries. Such a mixed system consist of an hybrid differential equation that for special limits of its parameters reduces to ... More
Decision Error Probability in a Two-stage Communication Network for Smart Grids with Imperfect Data LinksAug 04 2016This paper analyzes a scenario where the distribution system operator needs to estimate whether the average power demand in a given period is above a predetermined threshold using an 1-bit memoryless scheme. Specifically, individual smart-meters periodically ... More
Secondary flows of viscoelastic fluids in serpentine microchannelsOct 29 2018Feb 12 2019Secondary flows are ubiquitous in channel flows, where small velocity components perpendicular to the main velocity appear due to the complexity of the channel geometry and/or that of the flow itself such as from inertial or non-Newtonian effects, etc. ... More
Star Formation in the W49A Molecular Cloud: Birth of a Massive Star ClusterAug 31 2004The W49A star-forming region is embedded in a 10^6 solar mass molecular cloud, one of the most massive in our Galaxy. It has been long known as one of the most luminous radio HII regions, containing 30-40 compact and ultracompact HII regions and several ... More
On the Secrecy of Interference-Limited Networks under Composite Fading ChannelsNov 14 2014This paper deals with the secrecy capacity of the radio channel in interference-limited regime. We assume that interferers are uniformly scattered over the network area according to a Point Poisson Process and the channel model consists of path-loss, ... More
Fundamental physics constraints from testing the stability of the fine-structure constant with the ELTsFeb 07 2019The increased collecting area of the ELTs will bring fainter high-z targets within the reach of high-resolution ultra-stable spectrographs, thus enabling a new generation of precision consistency tests, including tests of the stability of nature's fundamental ... More
Massive Star Formation in the W49 Giant Molecular Cloud: Implications for the Formation of Massive Star ClustersSep 16 2004We present results from JHKs imaging of the densest region of the W49 molecular cloud. In a recent paper (Alves & Homeier 2003), we reported the detection of (previously unknown) massive stellar clusters in the well-known giant radio HII region W49A, ... More
Discovery of New Faint Northern Galactic Planetary NebulaeJun 12 2012We present the discovery of 6 nebular objects made by amateur astronomers. Four of these discoveries are clearly planetary nebulae (PNe), one is a possible PN, and another is a likely H II region. The bipolar nebula Ou4 presents the largest angular extent ... More
Decoupling inequalities and supercritical percolation for the vacant set of random walk loop soupAug 03 2018It has been recently understood (arXiv:1212.2885, arXiv:1310.4764, arXiv:1410.0605) that for a general class of percolation models on $\mathbb{Z}^d$ satisfying suitable decoupling inequalities, which includes i.a.\ Bernoulli percolation, random interlacements ... More
Error threshold in finite populationsSep 23 1997Mar 31 1998A simple analytical framework to study the molecular quasispecies evolution of finite populations is proposed, in which the population is assumed to be a random combination of the constiyuent molecules in each generation,i.e., linkage disequilibrium at ... More
A new Level-set based Protocol for Accurate Bone Segmentation from CT ImagingMay 12 2015In this work it is proposed a medical image segmentation pipeline for accurate bone segmentation from CT imaging. It is a two-step methodology, with a pre-segmentation step and a segmentation refinement step. First, the user performs a rough segmenting ... More
On the trace anomaly and the energy-momentum conservation of quantum fields at D=2 in classical curved backgroundsDec 09 2003We study the conformal symmetry and the energy-momentum conservation of scalar field interacting with a curved background at D=2. We avoid to incorporate the metric determinant into the measure of the scalar field to explain the conformal anomaly and ... More
Error threshold in the evolution of diploid organismsDec 09 1996The effects of error propagation in the reproduction of diploid organisms are studied within the populational genetics framework of the quasispecies model. The dependence of the error threshold on the dominance parameter is fully investigated. In particular, ... More
Micromechanical study of the dilatational response of porous solids with pressure-insensitive matrix displaying tension-compression asymmetryMar 17 2014Nov 26 2014In this paper, the dilatational response of porous solids with pressure-insensitive matrix displaying strength differential (SD) effects is investigated. To this end, micromechanical finite-element analyses of three-dimensional unit cells are carried ... More
Gravitational Waves in Braneworld Scenarios with AdS BackgroundDec 23 2010Feb 11 2012In this paper, we investigate gravitational waves as metric perturbations around a general warped 5-dimensional background. We find an analytical solution in Randall-Sundrum braneworld model and analyze the implications of braneworld models in the gravitational ... More
Electroweak Sector Under Scrutiny: A Combined Analysis of LHC and Electroweak Precision DataDec 03 2018We perform a comprehensive study of the Higgs couplings, gauge-boson couplings to fermions and triple gauge boson vertices. We work in the framework of effective theories including the effects of the dimension-six operators contributing to these observables. ... More
Legendrian contact homology and topological entropySep 12 2014Apr 23 2016In this paper we study the growth rate of a version of Legendrian contact homology, which we call strip Legendrian contact homology, in 3-dimensional contact manifolds and its relation to the topological entropy of Reeb flows. We show that: if for a pair ... More
The Cantor's First Diagonal Formalized and ExtendedMay 18 2013We examinate, formalize and extend the reasoning behind the Cantor's first diagonal argument, obtaining a simple closed-form expression for a bijection between $\mathbb{N}^k$ and $\mathbb{N}$.
Existence of standing waves solution for a Nonlinear Schrödinger equations in $\mathbb{R}^{N}$Aug 02 2015In this paper, we investigate the existence of positive solution for the following class of elliptic equation $$ - \epsilon^{2}\Delta u +V(x)u= f(u) \,\,\,\, \mbox{in} \,\,\, \mathbb{R}^{N}, $$ where $\epsilon >0$ is a positive parameter, $f$ has a subcritical ... More
Existence of positive solution for a nonlinear elliptic equation with saddle-like potential and nonlinearity with exponential critical growth in $\mathbb{R}^{2}$Jun 16 2015In this paper, we use variational methods to prove the existence of positive solution for the following class of elliptic equation $$ -\epsilon^{2}\Delta{u}+V(z)u=f(u) \,\,\, \mbox{in} \,\,\, \mathbb{R}^{2}, $$ where $\epsilon >0$ is a positive parameter, ... More
Dirac-Surface-State-Dominated Spin to Charge Current Conversion in the Topological Insulator $(Bi_{0.22}Sb_{0.78})_2Te_3$ Films at Room TemperatureOct 17 2017We report the spin to charge current conversation in an intrinsic topological insulator (TI) $(Bi_{0.22}Sb_{0.78})_2Te_3$ film at room temperature. The spin currents are generated in a thin layer of permalloy (Py) by two different processes, spin pumping ... More
The Li-age correlation: the Sun is unusually Li deficient for its ageMar 07 2019The present work aims to examine in detail the depletion of lithium in solar twins to better constrain stellar evolution models and investigate its possible connection with exoplanets. We employ spectral synthesis in the region of the asymmetric 6707.75 ... More
ALMA reveals the magnetic field evolution in the high-mass star forming complex G9.62+0.19May 01 2019May 13 2019Context. The role of magnetic fields during the formation of high-mass stars is not yet fully understood, and the processes related to the early fragmentation and collapse are largely unexplored today. The high-mass star forming region G9.62+0.19 is a ... More
A sub-parsec resolution simulation of the Milky Way: Global structure of the ISM and properties of molecular cloudsJul 22 2013Sep 06 2013We present a self-consistent hydrodynamical simulation of a Milky Way-like galaxy, at the resolution of 0.05 pc. The model includes star formation and a new implementation of stellar feedback through photo-ionization, radiative pressure and supernovae. ... More
Turbulence sets the initial conditions for star formation in high-pressure environmentsSep 03 2014Despite the simplicity of theoretical models of supersonically turbulent, isothermal media, their predictions successfully match the observed gas structure and star formation activity within low-pressure (P/k < 10^5 K cm^-3) molecular clouds in the solar ... More
Statistical Characterization of a 1D Random Potential Problem - with applications in score statistics of MS-based peptide sequencingJun 12 2008We provide a complete thermodynamic solution of a 1D hopping model in the presence of a random potential by obtaining the density of states. Since the partition function is related to the density of states by a Laplace transform, the density of states ... More
Multiple positive solutions for a Schrödinger logarithmic equationJan 29 2019May 14 2019This article concerns with the existence of multiple positive solutions for the following logarithmic Schr\"{o}dinger equation $$ \left\{ \begin{array}{lc} -{\epsilon}^2\Delta u+ V(x)u=u \log u^2, & \mbox{in} \quad \mathbb{R}^{N}, \\ %u(x)>0, & \mbox{in} ... More
On the Complexity of Quantum LanguagesApr 12 2004The standard inputs given to a quantum machine are classical binary strings. In this view, any quantum complexity class is a collection of subsets of $\{0,1\}^{*}$. However, a quantum machine can also accept quantum states as its input. T. Yamakami has ... More
Fibers in the NGC1333 proto-clusterMar 21 2017Are the initial conditions for clustered star formation the same as for non-clustered star formation? To investigate the initial gas properties in young proto-clusters we carried out a comprehensive and high-sensitivity study of the internal structure, ... More
A new method to unveil embedded stellar clustersJul 26 2017In this paper we present a novel method to identify and characterize stellar clusters deeply embedded in a dark molecular cloud. The method is based on measuring stellar surface density in wide-field infrared images using star counting techniques. It ... More
The mass function of dense molecular cores and the origin of the IMFDec 05 2006Context: Stars form in the cold dense cores of interstellar molecular clouds and the detailed knowledge of the spectrum of masses of such cores is clearly a key for the understanding of the origin of the IMF. To date, observations have presented somewhat ... More
Correlation Between Gas and Dust in Molecular Clouds: L977Sep 03 1998We report observations of the J =(1--0) C18O molecular emission line toward the L977 molecular cloud. To study the correlation between C18O emission and dust extinction we constructed a Gaussian smoothed map of the infrared extinction measured by Alves ... More
Current and future constraints on extended Bekenstein-type models for a varying fine-structure constantJan 24 2018There is a growing interest in astrophysical tests of the stability of dimensionless fundamental couplings, such as the fine-structure constant $\alpha$, as an optimal probe of new physics. The imminent arrival of the ESPRESSO spectrograph will soon enable ... More
Strong stochastic stability for non-uniformly expanding mapsFeb 26 2010We consider random perturbations of discrete-time dynamical systems. We give sufficient conditions for the stochastic stability of certain classes of maps, in a strong sense. This improves the main result in J. F. Alves, V. Araujo, Random perturbations ... More
Optimal Space-Time Block Code Designs Based on Irreducible Polynomials of Degree TwoJan 18 2019The main of this paper is to prove that in terms of normalized density, a space-time block code based on an irreducible quadratic polynomial over the Eisenstein integers is an optimal space-time block code compared with any quadratic space-time block ... More
Statistical stability for robust classes of maps with non-uniform expansionNov 22 2000We consider open sets of maps in a manifold $M$ exhibiting non-uniform expanding behaviour in some domain $S\subset M$. Assuming that there is a forward invariant region containing $S$ where each map has a unique SRB measure, we prove that under general ... More
Hyperbolic times: frequency versus integrabilityJul 18 2006We consider dynamical systems on compact manifolds, which are local diffeomorphisms outside an exceptional set (a compact submanifold). We are interested in analyzing the relation between the integrability (with respect to Lebesgue measure) of the first ... More
The Predictive Power of R0 in an Epidemic Probabilistic SystemFeb 12 2003An important issue in theoretical epidemiology is the epidemic threshold phenomenon, which specify the conditions for an epidemic to grow or die out. In standard (mean-field-like) compartmental models the concept of the basic reproductive number, R0, ... More
Fitting density models to observational data - The local Schmidt law in molecular cloudsOct 14 2013Oct 15 2013We consider the general problem of fitting a parametric density model to discrete observations, taken to follow a non-homogeneous Poisson point process. This class of models is very common, and can be used to describe many astrophysical processes, including ... More
A novel computational modelling to describe the anisotropic, remodelling and reorientation behaviour of collagen fibrres in articular cartilageJan 20 2016In articular cartilage the orientation of collagen fibres is not uniform, varying mostly with the depth on the tissue. Besides, the biomechanical response of each layer of the articular cartilage differs from the neighbouring ones, evolving through thickness ... More
Hipparcos distances of Ophiuchus and Lupus cloud complexesJan 22 2008Jan 24 2008We combine extinction maps from the Two Micron All Sky Survey (2MASS) with Hipparcos and Tycho parallaxes to obtain reliable and high-precision estimates of the distance to the Ophiuchus and Lupus dark complexes. Our analysis, based on a rigorous maximum-likelihood ... More
Dynamical histories of the IC348 and NGC1333 star-forming regions in PerseusMar 24 2017We present analyses of the spatial distributions of stars in the young (1 - 3 Myr) star-forming regions IC348 and NGC1333 in the Perseus Giant Molecular Cloud. We quantify the spatial structure using the $\mathcal{Q}$-parameter and find that both IC348 ... More
Storage Management in Modern Electricity Power GridsDec 02 2016This letter introduces a method to manage energy storage in electricity grids. Starting from the stochastic characterization of electricity generation and demand, we propose an equation that relates the storage level for every time-step as a function ... More
New Suns in the Cosmos?Jun 18 2013Jun 20 2013The present work reports on the discovery of three stars that we have identified to be rotating Sun-like stars, based on rotational modulation signatures inferred from light curves from the CoRoT mission's Public Archives. In our analysis, we performed ... More
On the Statistics of the Ratio of Non-Constrained Arbitrary α-μ Random Variables: a General Framework and ApplicationsFeb 21 2019In this paper, we derive closed-form exact expressions for the main statistics of the ratio of squared alpha-mu random variables, which are of interest in many scenarios for future wireless networks where generalized distributions are more suitable to ... More
The HIPASS survey of the Galactic plane in Radio Recombination LinesNov 17 2014Sep 15 2015We present a Radio Recombination Line (RRL) survey of the Galactic Plane from the HI Parkes All-sky Survey and associated Zone of Avoidance survey, which mapped the region l=196degr -- 0degr --52degr and |b| < 5degr at 1.4 GHz and 14.4 arcmin resolution. ... More
Estimation of the finite right endpoint in the Gumbel domainJun 06 2013A simple estimator for the finite right endpoint of a distribution function in the Gumbel max-domain of attraction is proposed. Large sample properties such as consistency and the asymptotic distribution are derived. A simulation study is also presented. ... More
A remark about mirror symmetry of elliptic curves and generalized complex geometryJun 11 2015Sep 17 2015In this short note we prove that in the case of elliptic curves, the isomorphism of generalized complex structure between $T$-dual manifolds described by Cavalcanti-Gualtieri coincides with the mirror map for elliptic curves described by Polishchuk and ... More
Existence of positive multi-bump solutions for a Schrödinger-Poisson system in $\mathbb{R}^{3}$Jan 13 2015In this paper we are going to study a class of Schr\"odinger-Poisson system $$ \left\{ \begin{array}{ll} - \Delta u + (\lambda a(x)+1)u+ \phi u = f(u) \mbox{ in } \,\,\, \mathbb{R}^{3},\\ -\Delta \phi=u^2 \mbox{ in } \,\,\, \mathbb{R}^{3}.\\ \end{array} ... More
Multipartite entanglement detection in bosonsSep 06 2004We propose a simple quantum network to detect multipartite entangled states of bosons, and show how to implement this network for neutral atoms stored in an optical lattice. We investigate the special properties of cluster states, multipartite entangled ... More
Existence and regularity of solutions for a class of singular (p(x),q(x))- Laplacian systemsJul 31 2016In this paper we study the existence of positive smooth solutions for a class of singular (p(x),q(x))- Laplacian systems by using sub and supersolution methods.
Existence of solutions for a class of singular elliptic systems with convection termJul 03 2013Nov 25 2013We show the existence of positive solutions for a class of singular elliptic systems with convection term. The approach combines pseudomonotone operator theory, sub and supersolution method and perturbation arguments involving singular terms.
Recurrence times and rates of mixing for invertible dynamical systemsNov 13 2006We consider invertible discrete-time dynamical systems having a hyperbolic product structure in some region of the phase space with infinitely many branches and variable recurrence time. We show that the decay of correlations of the SRB measure associated ... More
tt-geometry of filtered modulesAug 02 2017Aug 06 2017We compute the tensor triangular spectrum of perfect complexes of filtered modules over a commutative ring, and deduce a classification of the thick tensor ideals. We give two proofs: one by reducing to perfect complexes of graded modules which have already ... More
Centro-affine Codimension 2 Immersions: Umbilical and Inflection PointsNov 18 2018Nov 29 2018In this paper we consider centroaffine codimension 2 immersions with an eq\"uiaffine transversal vector field. We prove that asymptotic lines, resp. inflection points, of an immersion correspond to principal lines, resp. umbilical points, of its dual. ... More
2MASS wide field extinction maps - I. The Pipe nebulaJun 27 2006We present a 8 deg x 6 deg, high resolution extinction map of the Pipe nebula using 4.5 million stars from the Two Micron All Sky Survey (2MASS) point source catalog. The use of NICER, a robust and optimal technique to map the dust column density, allows ... More
Molecular clouds have power-law probability distribution functionsFeb 12 2015In this Letter we investigate the shape of the probability distribution of column densities (PDF) in molecular clouds. Through the use of low-noise, extinction-calibrated \textit{Herschel}/\textit{Planck} emission data for eight molecular clouds, we demonstrate ... More
Larson's third law and the universality of molecular cloud structureAug 25 2010Larson (1981) first noted a scaling relation between masses and sizes in molecular clouds that implies that these objects have approximately constant column densities. This original claim, based upon millimeter observations of carbon monoxide lines, has ... More
Suppressing vacuum fluctuations with vortex excitationsOct 22 2015The Casimir force for a planar gauge model is studied considering perfect conducting and perfect magnetically permeable boundaries. By using an effective model describing planar vortex excitations, we determine the effect these can have on the Casimir ... More
Markov structures and decay of correlations for non-uniformly expanding dynamical systemsMay 17 2002We consider non-uniformly expanding maps on compact Riemannian manifolds of arbitrary dimension, possibly having discontinuities and/or critical sets, and show that under some general conditions they admit an induced Markov tower structure for which the ... More
Sc and neutron-capture abundances in Galactic low- and high-alpha field halo starsJan 10 2017We determine relative abundance ratios for the neutron-capture elements Zr, La, Ce, Nd, and Eu for a sample of 27 Galactic dwarf stars with -1.5 < [Fe/H] <-0.8. We also measure the iron-peak element Sc. These stars separate into three populations (low- ... More
ESPRESSO's Early Commissioning Results and Performance Related to Tests of Fundamental Constant StabilityDec 14 2018ESPRESSO is a new high-resolution ultra-stable spectrograph for the VLT, which had its first light on Telescope on November 27th, 2017. The instrument is installed in the Combined Coud\'{e} Laboratory and linked to the 4 Units of Telescope through optical ... More
On the nonexistence of fat partially hyperbolic horseshoesJul 01 2005We show that there are no partially hyperbolic horseshoes with positive Lebesgue measure for diffeomorphisms whose class of differentiability is higher than 1. This generalizes a classical result by Bowen for uniformly hyperbolic horseshoes.
A coupled finite-volume solver for numerical simulation of electrically-driven flowsMar 27 2019The accuracy and stability of implicit CFD codes is frequently impaired by the decoupling between variables, which can ultimately lead to numerical divergence. Coupled solvers, which solve all the governing equations simultaneously, have the potential ... More
Higgs Signals in a Type I 2HDM or with a Sister HiggsJul 23 2012In models where an additional SU(2)-doublet that does not have couplings to fermions participates in electroweak symmetry breaking, the properties of the Higgs boson are changed. At tree level, in the neighborhood of the SM-like range of parameter space, ... More
Dust properties of the dark cloud IC5146 - Submillimeter and NIR imagingDec 11 2002Dec 12 2002We present the results of a submillimeter dust continuum study of a molecular ridge in IC5146 carried out at 850micron and 450micron with SCUBA on the James Clerk Maxwell Telescope (JCMT). The mapped region is 14'x2.5' in size (2pc x 0.3pc) and consists ... More
Time-dependent cosmological constant in the Jackiw-Teitelboim cosmologyJul 26 2002Mar 11 2003We study the obtainment of a time-dependent cosmological constant at D=2 in a model based on the Jackiw-Teitelboim cosmology. We show that the cosmological term goes to zero asymptotically and can induce a nonsingular behavior at the origin.
Gravitational collapse of the OMC-1 regionMar 09 2017Mar 29 2017We have investigated the global dynamical state of the Integral Shaped Filament in the Orion A cloud using new N$_2$H$^+$ (1-0) large-scale, IRAM30m observations. Our analysis of its internal gas dynamics reveals the presence of accelerated motions towards ... More
The Musca cloud: A 6 pc-long velocity-coherent, sonic filamentNov 19 2015Dec 08 2015Filaments play a central role in the molecular clouds' evolution, but their internal dynamical properties remain poorly characterized. To further explore the physical state of these structures, we have investigated the kinematic properties of the Musca ... More
On the volume of singular-hyperbolic setsSep 14 2005Sep 11 2006An attractor $\Lambda$ for a 3-vector field $X$ is singular-hyperbolic if all its singularities are hyperbolic and it is partially hyperbolic with volume expanding central direction. We prove that $C^{1+\alpha}$ singular-hyperbolic attractors, for some ... More
Mass reservoirs surrounding massive infrared dark clouds: A view by near-infrared dust extinctionSep 27 2011Context: Infrared Dark Clouds (IRDCs) harbor progenitors of high-mass stars. Little is known of the parental molecular clouds of the IRDCs. Aims: We demonstrate the feasibility of the near-infrared (NIR) dust extinction mapping in tracing the parental ... More
No evidence for mass segregation in massive young clustersNov 19 2008Dec 04 2008Aims. We investigate the validity of the mass segregation indicators commonly used in analysing young stellar clusters. Methods. We simulate observations by constructing synthetic seeing-limited images of a 1000 massive clusters (10^4 Msun) with a standard ... More
A simple agent-based spatial model of the economy: tools for policyOct 16 2015Feb 06 2016This study simulates the evolution of artificial economies in order to understand the tax relevance of administrative boundaries in the quality of life of its citizens. The modeling involves the construction of a computational algorithm, which includes ... More
Homotopy theory of dg sheavesNov 09 2015In this note we study the local projective model structure on presheaves of complexes on a site, i.e. we describe its classes of cofibrations, fibrations and weak equivalences. In particular, we prove that the fibrant objects are those satisfying descent ... More
A local lemma via entropy compressionSep 15 2015Jan 31 2017In the framework of the probabilistic method in combinatorics we present a new local lemma based on an entropy compression random algorithm and we show through examples that it can efficiently replace the Moser-Tardos algorithmic version of the Lov\'asz ... More
Perspectives for an Elko Phenomenology using Monojets at the 14 TeV LHCOct 14 2014The aim of this work is to explore the possibility to discover a fermionic field with mass dimension one, the Elko field, in the 14 TeV Large Hadron Collider (LHC), in processes with missing energy and one jet. We explore the possibility of a triple coupling ... More
A new old class of maximal monotone operatorsMay 29 2008In a recent paper in Journal of Convex Analysis the authors studied, in non-reflexive Banach spaces, a class of maximal monotone operators, characterized by the existence of a function in Fitzpatrick's family of the operator which conjugate is above the ... More