April 2007 arXiv papers — page 9

Álvaro Martínez Pérez, M. A. Morón

There is a well-known correspondence between infinite trees and ultrametric spaces which can be interpreted as an equivalence of categories and comes from considering the end space of the tree. In this equivalence, uniformly continuous maps between the end spaces are translated to some classes of coarse maps (or even classes of metrically proper lipschitz ma

V. Alana, J. L. Flores

The new formulation of the causal completion of spacetimes suggested in [1], and modified later in [2], is tested by computing the causal boundary for product spacetimes of a Lorentz interval and a Riemannian manifold. This is particularized for two important families of spacetimes, conformal to the previous ones: (standard) static spacetimes and Generalized

P. Lehnen, Th. Schapers, N. Kaluza, N. Thillosen

The magnetotransport in a set of identical parallel AlGaN/GaN quantum wire structures was investigated. The width of the wires was ranging between 1110 nm and 340 nm. For all sets of wires clear Shubnikov--de Haas oscillations are observed. We find that the electron concentration and mobility is approximately the same for all wires, confirming that the elect

Gabor Braun, Andras Nemethi

We derive a cut-and-paste surgery formula of Seiberg--Witten invariants for negative definite plumbed rational homology 3-spheres. It is similar to (and motivated by) Okuma's recursion formula [arXiv:math.AG/0610464, 4.5] targeting analytic invariants of splice quotient singularities. The two formulas combined provide automatically a proof of the equivar

Branislav Brutovsky, Denis Horvath, Vladimir Lisy

We demonstrate the power of the genetic algorithms to construct the cellular automata model simulating the growth of 2-dimensional close-to-circular clusters revealing the desired properties, such as the growth rate and, at the same time, the fractal behavior of their contours. The possible application of the approach in the field of tumor modeling is outlin

Alastair Kay

Here we present a problem related to the local Hamiltonian problem (identifying whether the ground state energy falls within one of two ranges) which is restricted to being translationally invariant. We prove that for problems with a fixed local dimension and O(\log(N))-body local terms, or local dimension N and 2-body terms, there are instances of the probl

G. Boero, S. Mouaziz, S. Rusponi, P. Bencok

We report on the measurement of element-specific magnetic resonance spectra at gigahertz frequencies using x-ray magnetic circular dichroism (XMCD). We investigate the ferrimagnetic precession of Gd and Fe ions in Gd-substituted Yttrium Iron Garnet, showing that the resonant field and linewidth of Gd precisely coincide with Fe up to the nonlinear regime of p

E. M. Kazaryan, L. S. Petrosyan, H. A. Sarkisyan

In this article it is shown that, Sommerfeld's coefficients for excitonic transitions in quantum wells are determined only with the principle quantum number within the framework of two-dimensional Coulomb potential. This is a consequence of hidden symmetry of two-dimensional Coulomb problem, conditioned by the existence of two-dimensional analog of the R

Vincent E. Sacksteder

The saddle points of a Lagrangian due to Efetov are analyzed. This Lagrangian was originally proposed as a tool for calculating systematic corrections to the Bethe approximation, a mean-field approximation which is important in statistical mechanics, glasses, coding theory, and combinatorial optimization. Detailed analysis shows that the trivial saddle point

Hongsheng Zhang, Zong-Hong Zhu, Lihua Yang

Hybrid Chaplygin gas model is put forward, in which the gases play the role of dark energy. For this model the coincidence problem is greatly alleviated. The effective equation of state of the dark energy may cross the phantom divide $w=-1$. Furthermore, the crossing behaviour is decoupled from any gravity theories. In the present model, $w<-1$ is only a tra

Guowu Meng

Let $D\ge 1$ be an integer. In the Enright-Howe-Wallach classification list of the unitary highest weight modules of $\widetilde{\mr{Spin}}(2, D+1)$, the (nontrivial) Wallach representations in Case II, Case III, and the mirror of Case III are special in the sense that they are precisely the ones that can be realized by the Hilbert space of bound states for

Saurya Das, Anindya Dey, Soumitra SenGupta

We generalise the RS braneworld model by taking into account a general stringy bulk containing the scalar dilaton field and the two-form Kalb-Ramond field, apart from gravity. Assuming small fluctuations around a RS background, the back-reacted warp factor is obtained. It is shown that the fine tuning problem in connection with the Higgs mass reappears in a

Xin-Heng Guo, Xing-Hua Wu

We study the possible bound states of the $K\bar K$ system in the Bethe-Salpeter formalism in the ladder and instantaneous approximations. We find that the bound states exist. However, these bound states have very small decay widths. Therefore, besides the possible $K\bar K$ component, there may be some other structures in the observed $f_0(980)$ and $a_0(98

A. O. Korotkevich, A. C. Newell, V. E. Zakharov

We wish to transmit messages to and from a hypersonic vehicle around which a plasma sheath has formed. For long distance transmission, the signal carrying these messages must be necessarily low frequency, typically 2 GHz, to which the plasma sheath is opaque. The idea is to use the plasma properties to make the plasma sheath appear transparent.

Hernando Quevedo

The thermodynamics of black holes is reformulated within the context of the recently developed formalism of geometrothermodynamics. This reformulation is shown to be invariant with respect to Legendre transformations, and to allow several equivalent representations. Legendre invariance allows us to explain a series of contradictory results known in the liter

K. Finlator, R. Dave

(Abridged) Using cosmological hydrodynamic simulations in combination with analytic modeling, we show that the galaxy stellar mass-metallicity relation (MZR) provides strong constraints on galactic outflows across cosmic time. We compare three outflow models: No outflows, a &#34;constant wind&#34; (cw) model that emulates the popular Dekel & Silk (1986) scen

Ritesh Kumar, M. K. Kadalbajoo

A general procedure to construct a class of simple and efficient high resolution Total Variation Diminishing (TVD) schemes for non-linear hyperbolic conservation laws by introducing anti-diffusive terms with the flux limiters is presented. In the present work the numerical flux function for space discretization is constructed as a combination of numerical fl

Jerome Martin

This pedagogical review aims at presenting the fundamental aspects of the theory of inflationary cosmological perturbations of quantum-mechanical origin. The analogy with the well-known Schwinger effect is discussed in detail and a systematic comparison of the two physical phenomena is carried out. In particular, it is demonstrated that the two underlying fo

Uwe Nagel, Tim Roemer

One of the main open questions in liaison theory is whether every homogeneous Cohen-Macaulay ideal in a polynomial ring is glicci, i.e. if it is in the G-liaison class of a complete intersection. We give an affirmative answer to this question for Stanley-Reisner ideals defined by simplicial complexes that are weakly vertex-decomposable. This class of complex

Jeng-Daw Yu

Let k be a perfect field of characteristic p > 2. In this note, we show that the local moduli space of a non-supersingular K3 surface over k with trivial deformation of the associated enlarged formal Brauer group admits a natural p-divisible formal group structure.

M. Ibison

This paper follows in the tradition of direct-action versions of electromagnetism having the aim of avoiding a balance of infinities wherein a mechanical mass offsets an infinite electromagnetic mass so as to arrive at a finite observed value. Given that, in this respect the direct-action approached ultimately failed because its initial exclusion of self-act

M. Ibison

Some arguments in favour of the existence of tachyons and extensions of the Lorentz Group are presented. On the former, it is observed that with a slight modification to standard electromagnetic theory a single superluminal charge will bind to itself in a self-sustaining circular orbit, suggestive of a (modified) electromagnetic interpretation of the strong

Frank J. Tipler

I argue that the (extended) Standard Model (SM) of particle physics and the renormalizable Feynman-Weinberg theory of quantum gravity comprise a theory of everything. I show that imposing the appropriate cosmological boundary conditions make the theory finite. The infinities that are normally renormalized away and the series divergence infinities are both el

Fabio DeMatteis, Mladen Georgiev

We are revisiting the efficiency problem of DKR nonradiative transitions at local electronic centers in polarizable solids. Following a brief survey, we formulate the general rate equations thereby defining the microscopic parameters controlling the nonradiative deexcitation. We also reproduce the quantum mechanical expressions for the energy conserving &#34

Siu A. Chin

Forward time step integrators are splitting algorithms with only positive splitting coefficients. When used in solving physical evolution equations, these positive coefficients correspond to positive time steps. Forward algorithms are essential for solving time-irreversible equations that cannot be evolved using backward time steps. However, forward integrat

The HERMES Collaboration, A. Airapetian

A series of semi-inclusive deep-inelastic scattering measurements on deuterium, helium, neon, krypton, and xenon targets has been performed in order to study hadronization. The data were collected with the HERMES detector at the DESY laboratory using a 27.6 GeV positron or electron beam. Hadron multiplicities on nucleus A relative to those on the deuteron, R

Ian Dobbs-Dixon, D. N. C. Lin

More than two dozen short-period Jupiter-mass gas giant planets have been discovered around nearby solar-type stars in recent years, several of which undergo transits, making them ideal for the detection and characterization of their atmospheres. Here we adopt a three-dimensional radiative hydrodynamical numerical scheme to simulate atmospheric circulation o

Koray Karahaliloglu

An easily implementable path solution algorithm for 2D spatial problems, based on excitable/programmable characteristics of a specific cellular nonlinear network (CNN) model is presented and numerically investigated. The network is a single layer bioinspired model which was also implemented in CMOS technology. It exhibits excitable characteristics with regio

Aleks Scholz, Jaime Coffey, Alexis Brandeker, Ray Jayawardhana

We present a study of rotation (vsini) and chromospheric activity (Halpha EW) based on an extensive set of high-resolution optical spectra obtained with MIKE on the 6.5m Magellan Clay telescope. Our targets are 74 F-M dwarfs in the young stellar associations Eta Cha, TW Hydrae, Beta Pic, and Tuc-Hor, spanning ages from 6 to 30 Myr. While the Halpha EW for mo

M. Ibison

It is shown that only the maximally-symmetric spacetimes can be expressed in both the Robertson-Walker form and in static form - there are no other static forms of the Robertson-Walker spacetimes. All possible static forms of the metric of the maximally-symmetric spacetimes are presented as a table. The findings are generalized to apply to functionally more

Leonor Saiz, Jose M. G. Vilar

Transcription regulation typically involves the binding of proteins over long distances on multiple DNA sites that are brought close to each other by the formation of DNA loops. The inherent complexity of the assembly of regulatory complexes on looped DNA challenges the understanding of even the simplest genetic systems, including the prototypical lac operon

Karim Hnia, Gérald Hugon, Ahmed Masmoudi, Jacques Mercier

In the peripheral nervous system, utrophin and the short dystrophin isoform (Dp116) are co-localized at the outermost layer of the myelin sheath of nerve fibers; together with the dystroglycan complex. In peripheral nerve, matrix metalloproteinase (MMP) creates a 30 kDa fragment of beta-dystroglycan, leading to a disruption of the link between the extracellu

Rainer Schmidt, Wilma Eerenstein, Thomas Winiecki, Finlay D. Morrison

Temperature dependent impedance spectroscopy enables the many contributions to the dielectric and resistive properties of condensed matter to be deconvoluted and characterized separately. We have achieved this for multiferroic epitaxial thin films of BiFeO3 (BFO) and BiMnO3 (BMO), key examples of materials with strong magneto-electric coupling. We demonstrat

G. Le Caer, C. Male, R. Delannay

The distributions of the spacing s between nearest-neighbor levels of unfolded spectra of random matrices from the beta-Hermite ensemble (beta-HE) is investigated by Monte Carlo simulations. The random matrices from the beta-HE are real-symmetric and tridiagonal where beta, which can take any positive value, is the reciprocal of the temperature in the classi

Christopher R. Myers, Ryan N. Gutenkunst, James. P. Sethna

We have built an open-source software system for the modeling of biomolecular reaction networks, SloppyCell, which is written in Python and makes substantial use of third-party libraries for numerics, visualization, and parallel programming. We highlight here some of the powerful features that Python provides that enable SloppyCell to do dynamic code synthes

R. N. Mohapatra, N. Okada, Hai-Bo Yu

The minimal SUSY SO(10) GUT models with {\bf 10}, {\bf 126} and {\bf 210} Higgs and only renormalizable couplings has been shown to provide a simple way to understand the neutrino mixings as well as the ratio $Δm^2_\odot/Δm^2_A$ in terms of quark mixing parameter $θ_{Cabibbo}$, provided neutrino masses are described by type II seesaw formula. However, in thi

C. Bot, F. Boulanger, M. Rubio, F. Rantakyro

CO observations have been so far the best way to trace molecular gas in external galaxies, but at low metallicity the gas mass deduced could be largely underestimated. At present, the kinematic information of CO data cubes are used to estimate virial masses and trace the total mass of the molecular clouds. Millimeter dust emission can also be used as a dense

Leonid Bedratyuk

Let $L$ be one of the finite dimensional Lie algebras $W_n({\bf m}),$ $S_n({\bf m}),$ $ H_n({\bf m})$ of Cartan type over an algebraically closed field of prime characteristic $p>0.$ For an elements $F$ of the symmetrical algebra $S(L)$ we found necessary and sufficient condition in order to the element $ad(\partial_1)^{p^{m_1}-1} ad(\partial_2)^{p^{m_2}-1}.

Zinovy Malkin, Natalia Miller

In this study, three empirical Free Core Nutation (FCN) models developed to the present time, MHB2000, Malkin&#39;s and Lambert&#39;s ones, are compared on the basis of representation of variations of the FCN amplitude and phase predicted by these models. It is possible to conclude, that the model of the author provides the most realistic representation of t

Rui Dilao, Rui Alves-Pires

We survey the few exact results on the Stormer problem describing the dynamics of charged particles in the Earth magnetosphere. The analysis of this system leads to the the conclusion that charged particles are trapped in the Earth magnetosphere or escape to infinity, and the trapping region is bounded by a torus-like surface, the Van Allen inner radiation b

Brendan Guilfoyle, Wilhelm Klingenberg

A number of results for C$^2$-smooth surfaces of constant width in Euclidean 3-space ${\mathbb{E}}^3$ are obtained. In particular, an integral inequality for constant width surfaces is established. This is used to prove that the ratio of volume to cubed width of a constant width surface is reduced by shrinking it along its normal lines. We also give a charac

C. N. Hao, X. Y. Xia, S. Mao, Z. G. Deng

We study the growth of black holes and stellar population in spheroids at high redshift using several (sub)mm-loud QSO samples. Applying the same criteria established in an earlier work, we find that, similar to IR QSOs at low redshift, the far-infrared emission of these (sub)mm-loud QSOs mainly originates from dust heated by starbursts. By combining low-z I

V. P. Ruban

A specific, genuinely three-dimensional mechanism of rogue wave formation, in a late stage of the modulational instability of a perturbed Stokes deep-water wave, is recognized through numerical experiments. The simulations are based on fully nonlinear equations describing weakly three-dimensional potential flows of an ideal fluid with a free surface in terms

M. D. Alloy, D. P. Menezes

n the present work we investigate one possible variation on the usual electrically neutral pulsars: the inclusion of electric charge. We study the effect of electric charge in pulsars assuming that the charge distribution is proportional to the energy density. All calculations were performed for zero temperature and fixed entropy equations of state.

M. Griesemer, D. Hasler

A new variant of the Feshbach map, called smooth Feshbach map, has been introduced recently by Bach et al., in connection with the renormalization analysis of non-relativistic quantum electrodynamics. We analyze and clarify its algebraic and analytic properties, and we generalize it to non-selfadjoint partition operators $χ$ and $\chib$.

K. Andriopoulos, P. G. L. Leach, A. Maharaj

We introduce the notion of Differential Sequences of ordinary differential equations. This is motivated by related studies based on evolution partial differential equations. We discuss the Riccati Sequence in terms of symmetry analysis, singularity analysis and identification of the complete symmetry group for each member of the Sequence. The singularity ana

L. O. V. Edwards, Michael J. Hudson, Michael L. Balogh, Russell J. Smith

We examine the optical emission line properties of Brightest Cluster Galaxies (BCGs) selected from two large, homogeneous datasets. The first is the X-ray selected National Optical Astronomy Observatory Fundamental Plane Survey (NFPS), and the second is the C4 catalogue of optically selected clusters built from the Sloan Digital Sky Survey Data Release ~3 (S

Daniele Angelosante, Ezio Biglieri, Marco Lops

We examine the problem of determining which nodes are neighbors of a given one in a wireless network. We consider an unsupervised network operating on a frequency-flat Gaussian channel, where $K+1$ nodes associate their identities to nonorthogonal signatures, transmitted at random times, synchronously, and independently. A number of neighbor-discovery algori

Philippe Balbiani, Andreas Herzig, Nicolas Troquard

We propose two alternatives to Xu&#39;s axiomatization of the Chellas STIT. The first one also provides an alternative axiomatization of the deliberative STIT. The second one starts from the idea that the historic necessity operator can be defined as an abbreviation of operators of agency, and can thus be eliminated from the logic of the Chellas STIT. The se

Massimiliano Gubinelli, Jozsef Lorinczi

Motivated by applications to quantum field theory we consider Gibbs measures for which the reference measure is Wiener measure and the interaction is given by a double stochastic integral and a pinning external potential. In order properly to characterize these measures through DLR equations, we are led to lift Wiener measure and other objects to a space of

Joao L. Yun, Jose M. Torrelles, Nuno C. Santos

We have observed IRAS06468-0325 obtaining optical and infrared images through IJHKs and L&#39; filters, K-band low-resolution spectroscopy, together with millimetre line observations of CO and CS. IRAS06468-0325 has a very unusual and enigmatic morphology with two components: a bright, close to point-like source (the diamond) and a sharp-edge ring-like struc

S. L. Skinner, S. A. Zhekov, M. Guedel, W. Schmutz

We present results of a 20 ksec X-ray observation of the Wolf-Rayet (WR) binary system WR 147 obtained with XMM-Newton. Previous studies have shown that this system consists of a nitrogen-type WN8 star plus an OB companion whose winds are interacting to produce a colliding wind shock. X-ray spectra from the pn and MOS detectors confirm the high extinction re

M. D. Alloy, D. P. Menezes

In the present work we investigate one possible variation on the usual static pulsars: the inclusion of rotation. We use a formalism proposed by Hartle and Thorne to calculate the properties of rotating pulsars with all possible compositions. All calculations were performed for zero temperature and also for fixed entropy equations of state.

Robert W. Easton, Ravi Vakil

Given an object over the algebraic closure Qbar of Q, there is often no reason for invariants of the corresponding holomorphic object to be preserved by the absolute Galois group Gal(Qbar/Q), and in general this is not true, although it is sometimes surprising to observe in practice. The case of covers of the projective line branched only over the points 0,

T. S. Boyajian, D. R. Gies, J. P. Dunn, C. D. Farrington

We present the results from an optical spectroscopic analysis of the massive stars HD 37366 and HD 54662. We find that HD 37366 is a double-lined spectroscopic binary with a period of 31.8187 +/- 0.0004 days, and HD 54662 is also a double lined binary with a much longer period of 557.8 +/- 0.3 days. The primary of HD 37366 is classified as O9.5 V, and it con

Olaf Stenull

We present a model for smectic elastomer membranes which includes elastic and liquid crystalline degrees of freedom. Based on our model, we determined the qualitative phase diagram of a smectic elastomer membrane using mean-field theory. This phase diagram is found to comprise five phases, viz. smectic-A--flat, smectic-A--crumpled, smectic-C--flat, smectic-C

Radhakrishnan Nagarajan

Linear measures such as cross-correlation have been used successfully to determine time delays from the given processes. Such an analysis often precedes identifying possible causal relationships between the observed processes. The present study investigates the impact of a positively correlated driver whose correlation function decreases monotonically with l

Alexey A. Kryukov

Isomorphisms of separable Hilbert spaces are analogous to isomorphisms of n-dimensional vector spaces. However, while n-dimensional spaces in applications are always realized as the Euclidean space R^n, Hilbert spaces admit various useful realizations as spaces of functions. In the paper this simple observation is used to construct a fruitful formalism of lo

Manuel Lladser, M. D. Betterton, Rob Knight

RNA motifs typically consist of short, modular patterns that include base pairs formed within and between modules. Estimating the abundance of these patterns is of fundamental importance for assessing the statistical significance of matches in genomewide searches, and for predicting whether a given function has evolved many times in different species or aros

J. M. Borrero

We study the magnetohydrostatic equilibrium of magnetic flux tubes with circular cross sections embedded in a magnetic surrounding atmosphere. We solve the static momentum equation in 2.5D to obtain the thermodynamics that are consistent with a prescribed velocity and magnetic fields. We show that force balance is roughly satisfied if the flux tube&#39;s mag

Dmitry Novikov

We prove an existential finiteness Varchenko-Khovanskii type result for integrals of rational 1-forms over the level curves of Darbouxian integrals.

Joel Merker, Egmont Porten

Employing Morse theory for the global control of monodromy and the method of analytic discs for local extension, we establish a version of the global Hartogs extension theorem in a singular setting: for every domain D of an (n-1)-complete normal complex space X of pure dimension n >= 2 and for every compact set K in D such that D - K is connected, holomorphi

Oleg Ruchayskiy

Adding 3 right-handed (sterile) neutrino to the Standard Model (SM) can solve several &#34;beyond the Standard Model&#34; problems within one consistent framework: explain neutrino oscillations and baryon asymmetry of the Universe and provide a dark matter (DM) candidate. In this talk I will present current status of astrophysical searches for the DM sterile

D. Benedetti, R. Loll, F. Zamponi

We perform a non-perturbative sum over geometries in a (2+1)-dimensional quantum gravity model given in terms of Causal Dynamical Triangulations. Inspired by the concept of triangulations of product type introduced previously, we impose an additional notion of order on the discrete, causal geometries. This simplifies the combinatorial problem of counting geo

F. Peano, G. Coppa, F. Peinetti, R. Mulas

Recently, the collisionless expansion of spherical nanoplasmas has been analyzed with a new ergodic model, clarifying the transition from hydrodynamic-like to Coulomb-explosion regimes, and providing accurate laws for the relevant features of the phenomenon. A complete derivation of the model is here presented. The important issue of the self-consistent init

Ganpathy Murthy, R. Shankar

The Hamiltonian Theory of the fractional quantum Hall effect is an operator description that subsumes many properties of Composite Fermions, applies to gapped and gapless cases, and has been found to provide results in quantitative accord with data on gaps, relaxation rates and polarizations at temperatures of $300mK$ and above. The only free parameter is $λ

Wang-Kong Tse, Ben Yu-Kuang Hu, S. Das Sarma

We study the Coulomb drag between two single graphene sheets in intrinsic and extrinsic graphene systems with no interlayer tunneling. The general expression for the nonlinear susceptibility appropriate for single-layer graphene systems is derived using the diagrammatic perturbation theory, and the corresponding exact zero-temperature expression is obtained

Paulo R. S. Carvalho, Marcelo M. Leite

We introduce the Callan-Symanzik method in the description of anisotropic as well as isotropic Lifshitz critical behaviors. Renormalized perturbation theories are defined by normalization conditions with nonvanishing masses and at zero external momenta. The orthogonal approximation is employed to obtain the critical indices $η_{L2}$, $ν_{L2}$, $η_{L4}$ and $

A. E. Dorokhov, S. V. Molodtsov, G. M. Zinovjev

The impact of filling up the Fermi sphere with the quarks, which dynamically generated their masses on the instanton liquid at finite temperature and baryonic/quark number density, is investigated. It is demonstrated, in particular, that the boundary of chiral symmetry restoration phase transition is shifted to the larger (about 100 MeV more) value of quark

L. Del Zanna, O. Zanotti, N. Bucciantini, P. Londrillo

We present a new numerical code, ECHO, based on an Eulerian Conservative High Order scheme for time dependent three-dimensional general relativistic magnetohydrodynamics (GRMHD) and magnetodynamics (GRMD). ECHO is aimed at providing a shock-capturing conservative method able to work at an arbitrary level of formal accuracy (for smooth flows), where the other

Falk Neugebohrn

Quantum gravity is analyzed from the viewpoint of the renormalization group. The analysis is based on methods introduced by J. Polchinski concerning the perturbative renormalization with flow equations. In the first part of this work, the program of renormalization with flow equations is reviewed and then extended to effective field theories that have a fini

John P. Wisniewski, Karen S. Bjorkman, Antonio M. Magalhaes, Antonio Pereyra

We present U,B,V,R,I imaging polarimetry of NGC 2100 and its surrounding environment, which comprise a part of the LMC 2 supershell. The morphology of the observed position angle distribution provides a tracer of the projected magnetic field in this environment. Our polarization maps detail regions exhibiting similarly aligned polarization position angles, a

C. Román-Zúñiga, C. Lada, A. Muench, J. Alves

We combined sensitive near-infrared data obtained with ground-based imagers on the ESO NTT and VLT telescopes with space mid-infrared data acquired with the IRAC imager on the Spitzer Space Telescope to calculate the extinction law A_λ/A_K as a function of λbetween 1.25 and 7.76 micron to an unprecedented depth in Barnard 59, a star forming, dense core locat

Grigoris Panotopoulos

Assisted chaotic inflation in brane cosmology is discussed. We work in the framework of Randall-Sundrum (RS) II model, in which adopting the RS condition the only parameter is the five-dimensional Planck mass. Using the scalar spectral index and the amplitude of scalar perturbations we determine both the mass of the scalar fields responsible for inflation an

A. P. Garyaka, R. M. Martirosov, S. V. Ter-Antonyan, N. Nikolskaya

On the basis of the extensive air shower (EAS) data obtained by the GAMMA experiment, the energy spectra and elemental composition of the primary cosmic rays are derived in the 1-100 PeV energy range. The reconstruction of the primary energy spectra is carried out using an EAS inverse approach in the framework of the SIBYLL2.1 and QGSJET01 interaction models

E. Paolini, M. Fossorier, M. Chiani

In this paper, the stability condition for low-density parity-check (LDPC) codes on the binary erasure channel (BEC) is extended to generalized LDPC (GLDPC) codes and doublygeneralized LDPC (D-GLDPC) codes. It is proved that, in both cases, the stability condition only involves the component codes with minimum distance 2. The stability condition for GLDPC co

Fajie Li, Reinhard Klette

This paper reports about the development of two provably correct approximate algorithms which calculate the Euclidean shortest path (ESP) within a given cube-curve with arbitrary accuracy, defined by $ε>0$, and in time complexity $κ(ε) \cdot {\cal O}(n)$, where $κ(ε)$ is the length difference between the path used for initialization and the minimum-length pa

Hasan Karabulut

Karabulut and Sibert (\textit{J. Math. Phys}. \textbf{38} (9), 4815 (1997)) have constructed an orthogonal set of functions from linear combinations of equally spaced Gaussians. In this paper we show that they are actually eigenfunctions of a q-oscillator in coordinate representation. We also reinterpret the coordinate representation example of q-oscillator

Andreas Ringwald

Recently the PVLAS collaboration reported the observation of a rotation of linearly polarized laser light induced by a transverse magnetic field -- a signal being unexpected within standard QED. In this review, we emphasize two mechanisms which have been proposed to explain this result: production of a single light neutral spin-zero particle or pair producti

Gilles Carron

The source of these notes is a series of lectures given at the CIMPA&#39;s summer school &#34;Recent Topics in Geometric Analysis&#34;.

Elsa S. Henriques, Andrey V. Solov&#39;yov

The unbinding process of a protein-ligand complex of major biological interest was investigated by means of a computational approach at atomistic classical mechanical level. An energy minimisation-based technique was used to determine the dissociation paths of the system by probing only a relevant set of generalized coordinates. The complex problem was reduc

T. Mineo, V. Mangano, S. Covino, G. Cusumano

We present a detailed analysis of the prompt and afterglow emission of GRB 050410 and GRB 050412 detected by Swift for which no optical counterpart was observed. The 15-150 keV energy distribution of the GRB 050410 prompt emission shows a peak energy at 53 keV. The XRT light curve of this GRB decays as a power law with a slope of alpha=1.06+/-0.04. The spect

Karine Sartelet, Hiroshi Hayami, Bruno Sportisse

In the framework of the model inter-comparison study - Asia Phase II (MICS2), where eight models are compared over East Asia, this paper studies the influence of different parameterizations used in the aerosol module on the aerosol concentrations of sulfate and nitrate in PM10. An intracomparison of aerosol concentrations is done for March 2001 using differe

V. Gogokhia

We have investigated a closed system of equations for the quark propagator, obtained earlier within our general approach to QCD at low energies. It implies quark confinement (the quark propagator has no pole, indeed), as well as the dynamical breakdown of chiral symmetry (a chiral symmetry preserving solution is forbidded). This system can be solved exactly

Sebastien Maret, Edwin A. Bergin

We present a detailed study of the ionization fraction of the Barnard 68 pre-stellar core, using millimeter H13CO+ and DCO+ lines observations. These observations are compared to the predictions of a radiative transfer model coupled to a chemical network that includes depletion on grains and gas phase deuterium fractionation. Together with previous observati

Laura Magrini, Edvige Corbelli, Daniele Galli

The evolution of radial gradients of metallicity in disk galaxies and its relation with the disk formation are not well understood. Theoretical models of galactic chemical evolution make contrasting predictions about the time evolution of metallicity gradients. To test chemical evolution models and trace the star formation and accretion history of low lumino

S. P. Sorella

The dynamical mass generation for gluons is discussed in Euclidean Yang-Mills theories supplemented with a renormalizable mass term. The mass parameter is not free, being determined in a self-consistent way through a gap equation which obeys the renormalization group. The example of the Landau gauge is worked out explicitly at one loop order. A few remarks o

Jonas R. Persson

Relativistic self-consistent-field calculations of the radial hyperfine integrals have been performed in the 4d-shell element ions. The comparison with available experimental results gives an estimate of configuration interaction effects in the hyperfine interaction in these ions. The results can also be used to derive nuclear moments from laserspectroscopic

Christopher R. Myers, James. P. Sethna

We describe a novel, interdisciplinary, computational methods course that uses Python and associated numerical and visualization libraries to enable students to implement simulations for a number of different course modules. Problems in complex networks, biomechanics, pattern formation, and gene regulation are highlighted to illustrate the breadth and flexib

S. Maniscalco, J. Piilo, K. -A. Suominen

We demonstrate the possibility of controlling the border between the quantum and the classical world by performing nonselective measurements on quantum systems. We consider a quantum harmonic oscillator initially prepared in a Schroedinger cat state and interacting with its environment. We show that the environment induced decoherence transforming the cat st

A. E. Nuncio Quiroz

Events with observed D* and/or muons in the final state were used to indicate the presence of beauty quark production and to study the correlations between the particles coming from the same or different B-hadrons. The Next-to-Leading Order (NLO) theoretical predictions for such processes were often available only at parton level. A method to calculate visib

Debaprasad Giri, Sanjay Kumar

The onset of an &#34;eye-phase&#34; and its role during the DNA unzipping is studied when a force is applied to the interior of the chain. The directionality of the hydrogen bond introduced here shows oscillations in force-extension curve similar to a &#34;saw-tooth&#34; kind of oscillations seen in the protein unfolding experiments. The effects of intermedi

Maíra Aguiar, Nico Stollenwerk

An epidemic multi-strain model with temporary cross-immunity shows chaos, even in a previously unexpected parameter region. Especially dengue fever models with strong enhanced infectivity on secondary infection have previously shown deterministic chaos motivated by experimental findings of antibody-dependent-enhancement (ADE). Including temporary cross-immun

Igor M. Loutsenko, Vyacheslav P. Spiridonov

We discuss a phase transition of the second order taking place in non-local 1D Ising chains generated by specific infinite soliton solutions of the KdV and BKP equations.

Sanjay Kumar, Debaprasad Giri

We consider a stiff polymer chain in poor solvent and apply a force at one end of the chain. We find that by varying the stiffness parameter, polymer undergoes a transition from the globule state to the folded like state. The conformation of folded state mimics the $β$-sheet as seen in titin molecule. Using exact enumeration technique, we study the extension

Thomas Preibisch

Several aspects concerning the origin of the very strong X-ray activity of T Tauri Stars (TTS) are still not well understood. Important new insight came recently from the Chandra Orion Ultradeep Project (COUP), a unique 10-day long Chandra observation of the Orion Nebula Cluster, and the XMM-Newton Extended Survey of the Taurus Molecular Cloud (XEST). Based

Damian H. Zanette

We address the role of multiplicative stochastic processes in modeling the occurrence of power-law city size distributions. As an explanation of the result of Zipf&#39;s rank analysis, Simon&#39;s model is presented in a mathematically elementary way, with a thorough discussion of the involved hypotheses. Emphasis is put on the flexibility of the model, as t

V. P. Kozhevnikov

We report on detection of negative superhumps in KR Aur which is the representative member of the VY Scl stars. The observations were obtained with the multi-channel photometer during 107 h. The analysis of the data clearly revealed brightness variations with a period of 3.771 +/- 0.005 h. This is 3.5 per cent less than the orbital period, suggesting it is a

M. Hernanz, G. Sala

We report on X-ray observations of Nova Sagittarius 1998 (V4633 Sgr), performed with XMM-Newton at three different epochs, 934, 1083 and 1265 days after discovery. The nova was detected with the EPIC cameras at all three epochs, with emission spanning the whole energy range from 0.2 to 10 keV. The X-ray spectra do not change significantly at the different ep

E. W. Hill, A. K. Geim, K. Novoselov, F. Schedin

Graphene - a single atomic layer of graphite - is a recently-found two-dimensional form of carbon, which exhibits high crystal quality and ballistic electron transport at room temperature. Soft magnetic NiFe electrodes have been used to inject polarized spins into graphene and a 10% change in resistance has been observed as the electrodes switch from the par