May 2009 arXiv papers — page 33

Admi Nazra

A real Bott tower is obtained as the orbit space of the $n$-torus $T^n$ by the free action of an elementary abelian 2-group $(\mathbb{Z}_2)^n$. This paper deals with the classification of 5-dimensional real Bott towers and study certain type of $n$-dimensional real Bott towers ($n\geq 6$).

Chao-Yang Pang, Chong-Bao Wang, Ben-Qiong Hu

Ant colony optimization (ACO) has been applied to the field of combinatorial optimization widely. But the study of convergence theory of ACO is rare under general condition. In this paper, the authors try to find the evidence to prove that entropy is related to the convergence of ACO, especially to the estimation of the minimum iteration number of convergenc

Matthew Headrick, Sam Kitchen, Toby Wiseman

We propose a general framework for solving the Einstein equation for static and Euclidean metrics. First, we address the issue of gauge-fixing by borrowing from the Ricci-flow literature the so-called DeTurck trick, which renders the Einstein equation strictly elliptic and generalizes the usual harmonic-coordinate gauge. We then study two algorithms, Ricci-f

Salvatore Federico, Ben Goldys, Fausto Gozzi

We study a class of optimal control problems with state constraints where the state equation is a differential equation with delays. This class includes some problems arising in economics, in particular the so-called models with time to build. We embed the problem in a suitable Hilbert space H and consider the associated Hamilton-Jacobi-Bellman (HJB) equatio

Stephen Krzyk, Alexander von Schmidsfeld, Mathias Kläui, Ulrich Rüdiger

We have investigated the magnetoresistance of Permalloy (Ni80Fe20) films with thicknesses ranging from a single monolayer to 12 nm, grown on Al2O3, MgO and SiO2 substrates. Growth and transport measurements were carried out under cryogenic conditions in UHV. Applying in-plane magnetic vector fields up to 100 mT, the magnetotransport properties are ascertaine

Iryna Egorova, Johanna Michor, Gerald Teschl

We provide a rigorous treatment of the inverse scattering transform for the entire Toda hierarchy for solutions which are asymptotically close to (in general) different finite-gap solutions as $n\to\pm\infty$.

A. Bartl, K. Hohenwarter-Sodek, T. Kernreiter, O. Kittel

We study the CP-violating terms of the spin-spin correlations in neutralino production and their subsequent two-body decays into sleptons plus leptons at the ILC. We analyze CP-sensitive observables with the help of T-odd products of the spin-spin terms. These terms depend on the polarizations of both neutralinos, with one polarization perpendicular to the p

Indira Chatterji, T. N. Venkataramana

We prove in a large number of cases, that a Zariski dense discrete subgroup of a simple real algebraic group $G$ which contains a higher rank lattice is a lattice in the group $G$. For example, we show that a Zariski dense subgroup of $SL_n({\mathbb R})$ which contains $SL_3({\mathbb Z})$ in the top left hand corner, is conjugate to $SL_n({\mathbb Z})$ .

Nicola Mazzari

We define and study the properties of the category ${\sf FHS}_n$ of formal Hodge structure of level $\le n$ following the ideas of L. Barbieri-Viale who discussed the case of level $\le 1$. As an application we describe the generalized Albanese variety of Esnault, Srinivas and Viehweg via the group $\Ext^1$ in ${\sf FHS}_n$. This formula generalizes the clas

Silvia Galli, Alessandro Melchiorri, George F. Smoot, Oliver Zahn

We present new constraints on cosmic variations of Newton's gravitational constant by making use of the latest CMB data from WMAP, BOOMERANG, CBI and ACBAR experiments and independent constraints coming from Big Bang Nucleosynthesis. We found that current CMB data provide constraints at the 10% level, that can be improved to 3% by including BBN data. We

Dan Zhang, Qiao-Yan Zhao, Qiu-Yang Zhang

The $DK$ interaction is relevant to the interpretation of the $D_{sJ}(2317)$. We dynamically investigate $S$-wave $DK$ interactions in the chiral SU(3) quark model by solving the resonating group method equation. The numerical results show an attraction between $D$ and $K$, which is from boson exchanges between light quarks. However, such an attraction is no

Daiji Kimura, Kang Young Lee, Takuya Morozumi, Keita Nakagawa

CP violation of the charged lepton sector has not been found yet. Tau is a unique charged lepton which can decay into hadrons. In this talk, we argue what kind of new physics can be studied with CP violation of tau lepton decays. We also disucuss how to handle hadronic final state interactions for a prediction of the direct CP violation.

Juan A. Bonachela, Miguel A. Munoz

The existence of true scale-invariance in slowly driven models of self-organized criticality without a conservation law, as forest-fires or earthquake automata, is scrutinized in this paper. By using three different levels of description - (i) a simple mean field, (ii) a more detailed mean-field description in terms of a (self-organized) branching processes,

A. A. Korshunova, O. S. Rozanova

Proceeding from the method of stochastic perturbation of a Langevin system associated with the non-viscous Burgers equation we construct a solution to the Riemann problem for the non-interacting particles and sticky particles systems. We analyze the difference in the behavior of discontinuous solutions for these two models and relations between them.

Sunil Mukhi, Probir Roy

This non-technical review article is aimed at readers with some physics background, including beginning research students. It provides a panoramic view of the main theoretical developments in high energy physics since its inception more than half a century ago, a period in which experiments have spanned an enormous range of energies, theories have been devel

Hirohito Hayashi, Masashi Chiba

We investigate the dynamical effects of dark matter subhalos on the structure and evolution of a galactic disk, using semi-analytic method that includes approximated and empirical relations as achieved in detailed numerical simulations of the cold dark matter model. We calculate the upper limit for the size of a galactic disk at a specific redshift $z$, base

Antoine Petiteau, Yu Shang, Stanislav Babak

In this work we use genetic algorithm to search for the gravitational wave signal from the inspiralling massive Black Hole binaries in the simulated LISA data. We consider a single signal in the Gaussian instrumental noise. This is a first step in preparation for analysis of the third round of the mock LISA data challenge. We have extended a genetic algorith

Jaiseung Kim, Pavel Naselsky

We show a primordial non-linear &#34;f_NL&#34; term may produce unphysically large CMB anisotropy for a red-tilted primordial power spectrum (n<1), because of coupling to primordial fluctuation on the largest scale. We consider a primordial power spectrum models of a running spectral index, and a transition at very low wavenumbers. We find that only negative

Tiziana Calamoneri

The L(2, 1)-labeling of a digraph G is a function f from the node set of $G$ to the set of all nonnegative integers such that $|f(x)-f(y)| \geq 2$ if $x$ and $y$ are at distance 1, and $f(x)=f(y)$ if $x$ and $y$ are at distance 2, where the distance from vertex $x$ to vertex $y$ is the length of a shortest dipath from $x$ to $y$. The minimum of the maximum u

B. S. Wang, P. Tong, Y. P. Sun, X. B. Zhu

The magnetic and magnetocaloric properties of Ga1-xCMn3+x have been investigated. Reversible magnetocaloric effect (MCE) occurs near the Curie temperature TC. The magnetic entropy change decreases with increasing x, though TC and magnetization increases. Meanwhile, the temperature span of vs. T plot becomes well broadened with x. Due to the competition betwe

T. Shi, C. P. Sun

We study how to recover the unitarity of Lee model with the help of bi-orthogonal basis approach, when the physical coupling constant in renormalization exceeds its critical value, so that the Lee&#39;s Hamiltonian is non-Hermitian with respect to the conventional inner product. In a very natural fashion, our systematic approach based on bi-orthogonal basis

Chao Cao, Yu-ning Wu, Rashid Hamdan, Yun-Peng Wang

By carefully choosing parameters and including more semi-core orbitals as valence electrons, we have constructed a high quality projected augmented wave (PAW) dataset that yields results comparable to existing full-potential linearized augmented plane-wave calculations. The dataset was then applied to BaFe$_2$As$_2$ to study the effects of different levels o

L. W. Kastens, S. B. Cahn, A. Manzur, D. N. McKinsey

We report the preparation of a Kr-83m source and its subsequent use in calibrating a liquid xenon detector. Kr-83m atoms were produced through the decay of Rb-83 atoms trapped in zeolite molecular sieve and were then introduced into liquid xenon. Decaying Kr-83m nuclei were detected through liquid xenon scintillation. Conversion electrons with energies of 9.

L. A. Falkovsky

The tight-binding model of a graphene bilayer is used to find the gap between the conduction and valence bands, as a function of both the gate voltage and as the doping by donors or acceptors. The total Hartree energy is minimized and the equation for the gap is obtained. This equation for the ratio of the gap to the chemical potential is determined only by

K. -I. Izawa, Fuminobu Takahashi, T. T. Yanagida, Kazuya Yonekura

A new class of models of dynamical supersymmetry breaking is proposed. The models are based on SU(N_C) gauge theories with N_F(<N_C) flavors of quarks and singlets. Dynamically generated superpotential exibits runaway behavior. By embedding the models into conformal field theories at high energies, the runaway potential is stabilized by strong quantum correc

Yoshio Sano

The notion of a competition graph was introduced by J. E. Cohen in 1968. The competition graph C(D) of a digraph D is a (simple undirected) graph which has the same vertex set as D and has an edge between two distinct vertices x and y if and only if there exists a vertex v in D such that (x,v) and (y,v) are arcs of D. For any graph G, G together with suffici

Steven Duplij, Sergey Sinel&#39;shchikov

A complete list of Uq(sl2)-module algebra structures on the quantum plane is produced and the (uncountable family of) isomorphism classes of these structures are described. The composition series of representations in question are computed. The classical limits of the Uq(sl2)-module algebra structures are discussed.

Chanju Kim, Yoonbai Kim, O-Kab Kwon, Hiroaki Nakajima

We study Aharony-Bergman-Jafferis-Maldacena (ABJM) theory without and with mass deformation. It is shown that maximally supersymmetry preserving, D-term, and F-term mass deformations of single mass parameter are equivalent. We obtain vortex-type half-BPS equations and the corresponding energy bound. For the undeformed ABJM theory, the resulting half-BPS equa

Taichi Kato, Akira Imada, Makoto Uemura, Daisaku Nogami

We systematically surveyed period variations of superhumps in SU UMa-type dwarf novae based on newly obtained data and past publications. In many systems, the evolution of superhump period are found to be composed of three distinct stages: early evolutionary stage with a longer superhump period, middle stage with systematically varying periods, final stage w

Kelly Jabbusch, Stefan Kebekus

Consider a smooth, projective family of canonically polarized varieties over a smooth, quasi-projective base manifold Y, all defined over the complex numbers. It has been conjectured that the family is necessarily isotrivial if Y is special in the sense of Campana. We prove the conjecture when Y is a surface or threefold. The proof uses sheaves of symmetric

Takeshi Kobayashi, Shinji Mukohyama, Brian A. Powell

We obtain cosmological constraints on models of inflation which exhibit rapid roll solutions. Rapid roll attractors exist for potentials with large mass terms and are thus of interest for inflationary model building within string theory. We constrain a general ansatz for the power spectrum arising from rapid roll inflation that, in the small field limit, can

W. A. Coish, J. Baugh

We review recent theoretical and experimental advances toward understanding the effects of nuclear spins in confined nanostructures. These systems, which include quantum dots, defect centers, and molecular magnets, are particularly interesting for their importance in quantum information processing devices, which aim to coherently manipulate single electron s

A. Rodriguez-Gonzalez, A. C. Raga, J. Canto

Intermediate and high velocity HI clouds rain onto the plane of our Galaxy. They are observed at heights of between 500 and 1500 pc, falling onto the Galactic plane at velocities from 50 to 140 km s$^{-1}$. To explain the origin of these clouds, we present a galactic fountain model, driven by the wind from a super stellar cluster (SSC). We solve the equation

Francesco Giacosa, Thomas Gutsche, Valery E. Lyubovitskij

We reply to the preceding Comment by E. van Beveren et al., arXiv:0811.2589 [hep-ph].

Luis Lopez-Oliveros, Sidney I. Resnick

We refine a stimulating study by Sarvotham et al. [2005] which highlighted the influence of peak transmission rate on network burstiness. From TCP packet headers, we amalgamate packets into sessions where each session is characterized by a 5-tuple (S, D, R, Peak R, Initiation T)=(total payload, duration, average transmission rate, peak transmission rate, ini

CDF Collaboration, T. Aaltonen

We have measured the differential cross section for the inclusive production of psi(2S) mesons decaying to mu^{+} mu^{-1} that were produced in prompt or B-decay processes from ppbar collisions at 1.96 TeV. These measurements have been made using a data set from an integrated luminosity of 1.1 fb^{-1} collected by the CDF II detector at Fermilab. For events

C. T. Kennaugh

This dissertation investigates the relative complexity between a continuum and its proper subcontinua, in particular, providing examples of atriodic n-od-like continua. Let X be a continuum and n be an integer greater than or equal to three. If X is homeomorphic to an inverse limit of simple-n-od graphs with simplicial bonding maps and is simple-(n-1)-od-lik

L. N. Granda, A. Oliveros, W. Cardona

We study the age problem of the universe with the holographic DE model introduced in [21], and test the model with some known old high redshift objects (OHRO). The parameters of the model have been constrained using the SNIa, CMB and BAO data set. We found that the age of the old quasar APM 08 279+5255 at z = 3.91 can be described by the model.

Gerardo Hernandez-del-Valle

In this paper we derive the density $φ$ of the first time $T$ that a continuous martingale $M$ with non-random quadratic variation $<M>_\cdot:=\int_0^\cdot h^2(u)du$ hits a moving boundary $f$ which is twice continuously differentiable, and $f&#39;/h\in\mathbb{C}^2[0,\infty)$. Thus, this work is an extension to case in which $M$ is in fact a one-dimensional

Diana López Nacir, Francisco D. Mazzitelli

We review our recent results on the renormalization procedure for a free quantum scalar field with modified dispersion relations in curved spacetimes. For dispersion relations containing up to $2s$ powers of the spatial momentum, the subtraction necessary to renormalize $<ϕ^2>$ and $<T_{μν}>$ depends on $s$. We first describe our previous analysis for spatia

J. E. Krick, J. A. Surace, D. Thompson, M. L. N. Ashby

We present infrared luminosities, star formation rates, colors, morphologies, locations, and AGN properties of 24 micron-detected sources in photometrically detected high-redshift clusters in order to understand the impact of environment on star formation and AGN evolution in cluster galaxies. We use three newly-identified z=1 clusters selected from the IRAC

Gerardo Hernandez-del-Valle

We obtain explicit solutions for the density $φ_T$ of the first-time $T$ that a one-dimensional Brownian process $B$ reaches the twice, continuously differentiable moving boundary $f$ and such that $f&#39;&#39;(t)\geq 0$ for all $t\in \mathbb{R}^+$. We do so by finding the expected value of some functionals of a 3-dimensional Bessel bridge $\tilde{X}$ and ex

Michael M. Shara, Anthony F. J. Moffat, Jill Gerke, David R. Zurek

The discovery of new Wolf-Rayet (WR) stars in our Galaxy via large-scale narrowband optical surveys has been severely limited by dust extinction. Recent improvements in infrared technology have made narrowband-broadband imaging surveys viable again. We report a new J, K and narrow-band imaging survey of 300 square degrees of the plane of the Galaxy, spanning

Dhruv Mubayi

For various triple systems $F$, we give tight lower bounds on the number of copies of $F$ in a triple system with a prescribed number of vertices and edges. These are the first such results for hypergraphs, and extend earlier theorems of Bollobás, Frankl, Füredi, Keevash, Pikhurko, Simonovits, and Sudakov who proved that there is one copy of $F$. A sample re

Swiat R. Gal, Tadeusz Januszkiewicz

More than once we have heard that the Charney-Davis Conjecture makes sense only for odd-dimensional spheres. This is to point out that in fact it is also a statement about even-dimensional spheres.

Taha Sochi

In this article, the extensional flow and viscosity and the converging-diverging geometry were examined as the basis of the peculiar viscoelastic behavior in porous media. The modified Bautista-Manero model, which successfully describes shearthinning, elasticity and thixotropic time-dependency, was used for modeling the flow of viscoelastic materials which a

Michelle Doherty, Magda Arnaboldi, Payel Das, Ortwin Gerhard

We present high resolution FLAMES/VLT spectroscopy of intracluster planetary nebula (ICPN) candidates, targeting three new fields in the Virgo cluster core with surface brightness down to mu_B = 28.5. Based on the projected phase space information we separate the old and 12 newly-confirmed PNs into galaxy and intracluster components. The M87 PNs are confined

A. T. Wu, R. A. Rimmer, X. Y. Lu, F. Eozenou

A new surface treatment technique for niobium (Nb) Superconducting Radio Frequency (SRF) cavities called Buffered Electropolishing (BEP) has been developed at JLab. It was found that BEP could produce the smoothest surface finish on Nb samples ever reported in the literature. Experimental results revealed that the Nb removal rate of BEP could reach as high a

D. Farrah, B. Connolly, N. Connolly, H. Spoon

We apply methods from Bayesian inferencing and graph theory to a dataset of 102 mid-infrared spectra, and archival data from the optical to the millimeter, to construct an evolutionary paradigm for z<0.4 infrared-luminous galaxies (ULIRGs). We propose that the ULIRG lifecycle consists of three phases. The first phase lasts from the initial encounter until ap

Daniel Kocevski, Andrew A. West, Maryam Modjaz

We model the mass distribution of long gamma-ray burst (GRB) host galaxies given recent results suggesting that GRBs occur in low metallicity environments. By utilizing measurements of the redshift evolution of the mass-metallicity (M-Z) relationship for galaxies, along with a sharp host metallicity cut-off suggested by Modjaz and collaborators, we estimate

Barbara Ercolano

We re-examine the well-known discrepancy between ionic abundances determined via the analysis of recombination lines (RLs) and collisionally excited lines (CELs). We show that abundance variations can be mimicked in a {\it chemically homogeneous} medium by the presence of dense X-ray irradiated regions which present different ionisation and temperature struc

S. K. Domokos, H. R. Grigoryan, J. A. Harvey

We employ both top-down and bottom-up holographic dual models of QCD to calculate vertex functions and couplings that are induced by the five dimensional Chern-Simons term. We use these couplings to study the photoproduction of $f_1$ mesons. The Chern-Simons-term-induced interaction leads to a simple relation between the polarization of the incoming photon a

L. L. Cowie, A. J. Barger, W. -H. Wang, J. P. Williams

We report a highly significant Submillimeter Array (SMA) detection of the prototypical submillimeter source HDF 850.1, which is the brightest submillimeter source in the Hubble Deep Field-North proper. The detection yields an extremely precise position of RA(2000)=12:36:51.99 and Dec(2000)=+62:12:25.83 with a 1-sigma positional uncertainty of 0.17 arcsec. Th

O. Cohen, J. J. Drake, V. L. Kashyap, T. I. Gombosi

We simulate the effect of latitudinal variations in the location of star spots, as well as their magnetic field strength, on stellar angular momentum loss to the stellar wind. We use the Michigan solar corona global MagnetoHydroDynamic model, which incorporates realistic relation between the magnetic field topology and the wind distribution. We find that the

Noga Alon, Jozsef Balogh, Bela Bollobas, Robert Morris

A hereditary property of graphs is a collection of graphs which is closed under taking induced subgraphs. The speed of ¶is the function n \mapsto |¶_n|, where ¶_n denotes the graphs of order n in ¶. It was shown by Alekseev, and by Bollobas and Thomason, that if ¶is a hereditary property of graphs then |¶_n| = 2^{(1 - 1/r + o(1))n^2/2}, where r = r(¶) \in \N

V Miranda, Sergio E. Joras, Ioav Waga, Miguel Quartin

Several authors have argued that self-consistent $f(R)$ gravity models distinct from $Λ$CDM are almost ruled out. Confronting such claims, we present a particular two-parameter $f(R)$ model that: (a) is cosmologically viable and distinguishable from $Λ$CDM; (b) is compatible with the existence of relativistic stars; (c) is free of singularities of the Ricci

Amir Moradifam

We study the regularity of the extremal solution of the semilinear biharmonic equation $βΔ^2 u-τΔu=\fracλ{(1-u)^2}$ on a ball $B \subset \R^N$, under Navier boundary conditions $u=Δu=0$ on $\partial B$, where $λ>0$ is a parameter, while $τ>0$, $β>0$ are fixed constants. It is known that there exists a $λ^{*}$ such that for $λ>λ^{*}$ there is no solution whil

L. G. Althaus, J. A. Panei, A. D. Romero, R. D. Rohrmann

Motivated by the recent detection of single and binary He-core white dwarfs in metal-rich clusters, we present a full set of evolutionary calculations and colors appropriate for the study of such white dwarfs. The paper is also aimed at investigating whether stable hydrogen burning may constitute a main source of energy for massive He-core white dwarfs resul

K. Brown, M. Crisan, I. Tifrea

We consider the transport and the noise characteristics for the case of a T-shape double quantum dot system using the equation of motion method. Our theoretical results, obtained in an approximation equivalent to the Hartree-Fock approximation, account for non-zero on-site Coulomb interaction in both the detector and side dots. The existence of a non-zero Co

Amir Moradifam

Consider the problem {ll} Δ^2 u= λe^{u} &\text{in} B u=\frac{\partial u}{\partial n}=0 &\text{on}\partial B, where $B$ is the unit ball in $\R^N$ and $λ$ is a parameter. Unlike the Gelfand problem the natural candidate $u=-4\ln(|x|)$, for the extremal solution, does not satisfy the boundary conditions and hence showing the singular nature of the extremal sol

T. O. B. Schmidt, R. Neuhäuser, M. Mugrauer, A. Bedalov

In our ongoing search for close and faint companions around T Tauri stars in the Chamaeleon star-forming region, we recently (Schmidt et al 2008b) presented direct observations and integral field spectroscopy of a new common proper motion companion to the young T-Tauri star and Chamaeleon member CT Cha and discussed its properties in comparison to other youn

Matthew Daws

Given a (reduced) locally compact quantum group $A$, we can consider the convolution algebra $L^1(A)$ (which can be identified as the predual of the von Neumann algebra form of $A$). It is conjectured that $L^1(A)$ is operator biprojective if and only if $A$ is compact. The &#34;only if&#34; part always holds, and the &#34;if&#34; part holds for Kac algebras

Claudia L. Mendes de Oliveira, Eduardo S. Cypriano, Renato A. Dupke, Laerte Sodré

Fossil groups are systems with one single central elliptical galaxy and an unusual lack of luminous galaxies in the inner regions. The standard explanation for the formation of these systems suggests that the lack of bright galaxies is due to galactic cannibalism. In this study we show the results of an optical and X-ray analysis of RX J1340.6+4018, the prot

Andrzej Derdzinski

It is shown that a self-dual neutral Einstein four-manifold of Petrov type III, admitting a two-dimensional null parallel distribution compatible with the orientation, cannot be compact or locally homogeneous, and its maximum possible degree of mobility is 3. Diaz-Ramos, Garcia-Rio and Vazquez-Lorenzo found a general coordinate form of such manifolds. The pr

Michael A. Disanti, Geronimo L. Villanueva, Stefanie N. Milam, Lindsay N. Zack

Volatile organic emissions were detected post-perihelion in the long period comet C/2006 M4 (SWAN) in October and November 2006. Our study combines target-of-opportunity observations using the infrared Cryogenic Echelle Spectrometer (CSHELL) at the NASA-IRTF 3-m telescope, and millimeter wavelength observations using the Arizona Radio Observatory (ARO) 12-m

Philip du Toit, Katalin Grubits, Jerrold Marsden, Sorin Costiner

We address the inverse problem of designing isotropic pairwise particle interaction potentials that lead to the formation of a desired lattice when a system of particles is cooled. The design problem is motivated by the desire to produce materials with pre-specified structure and properties. We present a heuristic computation-free geometric method, as well a

Luana S. Pedroza, Antonio J. R. da Silva, Klaus Capelle

One of the standard generalized-gradient approximations (GGAs) in use in modern electronic-structure theory, PBE, and a recently proposed modification designed specifically for solids, PBEsol, are identified as particular members of a family of functionals taking their parameters from different properties of homogeneous or inhomogeneous electron liquids. Thr

T. Zykova-Timan, R. E. Rozas, J. Horbach, K. Binder

Using Molecular Dynamics (MD) and Monte Carlo (MC) simulations interfacial properties of crystal-fluid interfaces are investigated for the hard sphere system and the one-component metallic system Ni (the latter modeled by a potential of the embedded atom type). Different local order parameters are considered to obtain order parameter profiles for systems whe

P. Bhupathi, J. Hwang, R. M. Martin, J. Blankstein

Optical transmission measurements were made on 98% porosity silica aerogel samples under various degrees of uniaxial strain. Uniaxially compressed aerogels exhibit large birefringence, proportional to the amount of compression, up to the 15% strain studied. The birefringence is mostly reversible and reproducible through multiple compression-decompression cyc

T. O. B. Schmidt, R. Neuhäuser

We have searched for close and faint companions around T Tauri stars in the Chamaeleon star forming region. Two epochs of direct imaging data were taken with the VLT Adaptive Optics instrument NaCo in February 2006 and March 2007 in Ks band for the classical T Tauri star CT Cha together with a Hipparcos binary for astrometric calibration. Moreover a J band i

E. Ben-Naim, P. L. Krapivsky

We study structural properties of trees grown by preferential attachment. In this mechanism, nodes are added sequentially and attached to existing nodes at a rate that is strictly proportional to the degree. We classify nodes by their depth n, defined as the distance from the root of the tree, and find that the network is strongly stratified. Most notably, t

Sevil Salur

Measurements of strong suppression of inclusive hadron distributions and di-hadron correlations at high $p_{T}$, while providing evidence for partonic energy loss, also suffer from geometric biases due to the competition of energy loss and fragmentation. The measurements of fully reconstructed jets is expected to lack these biases as the energy flow is measu

Vitaly V. Ganusov, Aron E. Lukacher, Anthony M. Byers

Viral infections can be broadly divided into infections that are cleared from the host (acute) and those that persist (chronic). Why some viruses establish chronic infections while other do not is poorly understood. One possibility is that the host&#39;s immune response is impaired during chronic infections and is unable to clear the virus from the host. In

E. I. Vorobyov

(Abridged) We study numerically the applicability of the effective-viscosity approach for simulating the effect of gravitational instability (GI) in disks of young stellar objects with different disk-to-star mass ratios ξ. We adopt two α$-parameterizations for the effective viscosity based on Lin & Pringle (1990) and Kratter et al (2008) and compare the resu

C. Wang, Y. -T. Cui, J. Z. Sun, J. A. Katine

We calculate the efficiency with which magnetic tunnel junctions can be used as resonant detectors of incident microwave radiation via the spin-torque diode effect. The expression we derive is in good agreement with the sensitivities we measure for MgO-based magnetic tunnel junctions with an extended (unpatterned) magnetic pinned layer. However, the measured

P. Valageas

We study the decaying Burgers dynamics in $d$ dimensions for random Gaussian initial conditions. We focus on power-law initial energy spectra, such that the system shows a self-similar evolution. This is the case of interest for the "adhesion model" in cosmology and a standard framework for "decaying Burgers turbulence". We briefly describe how the system ca

Kevin P. Costello, Van Vu

We show that the absolute value of the determinant of a matrix with random independent (but not necessarily iid) entries is strongly concentrated around its mean. As an application, we show that the Godsil-Gutman and Barvinok estimators for the permanent of a strictly positive matrix give sub-exponential approximation ratios with high probability.

Tanmoy Laskar, David R. Soderblom, Jeff A. Valenti, John R. Stauffer

Pre-main sequence (PMS) binaries and multiples enable critical tests of stellar models if masses, metallicities, and luminosities of the component stars are known. We have analyzed high-resolution, high signal-to-noise echelle spectra of the quadruple-star system HD 98800 and using spectrum synthesis, computed fits to the composite spectrum for a full range

Michael T. Goodrich, Daniel S. Hirschberg

We study group-testing algorithms for resolving broadcast conflicts on a multiple access channel (MAC) and for identifying the dead sensors in a mobile ad hoc wireless network. In group-testing algorithms, we are asked to identify all the defective items in a set of items when we can test arbitrary subsets of items. In the standard group-testing problem, the

Giorgio Patrizio, Andrea Spiro

We study the problem of existence of stationary disks for domains in almost complex manifolds. As a consequence of our results, we prove that any almost complex domains which is a small deformations of a strictly linearly convex domain $D \subset C^n$ with standard complex structure admits a singular foliation by stationary disks passing through any given in

A. N. Ivanov, P. Kienle, M. Pitschmann

We propose a theoretical analysis of the experimental data on the time behaviour K-shell electron capture (EC) decays of atoms 180Re and 142Pm in solid targets, obtained recently by Faestermann et al. Phys. Lett. B 672, 227 (2009) and Vetter et al., Phys. Lett. B 670, 149 (2008). We show that the absence of the time modulation in these data rules out the exp

Brent Kerby

In 1993, Muzychuk \cite{muzychuk} showed that the rational Schur rings over a cyclic group $Z_n$ are in one-to-one correspondence with sublattices of the divisor lattice of $n$, or equivalently, with sublattices of the lattice of subgroups of $Z_n$. This can easily be extended to show that for any finite group $G$, sublattices of the lattice of characteristi

G. C. Baiesi Pillastrini

We have explored the hypothesis that the total mass-ratio of the two main galaxies of the Local Group: Andromeda Galaxy(M31) and the Milky Way (MW) can be constrained measuring the tidal force induced by the surrounding mass distribution, M31 included, on the MW. We argue that the total mass-ratio between the two groups can be approximated, at least qualitat

M. Yashima, H. Nishimura, H. Mukuda, Y. Kitaoka

We present $^{57}$Fe-NMR measurements of the novel normal and superconducting-state characteristics of the iron-arsenide superconductor Ba$_{0.6}$K$_{0.4}$Fe$_2$As$_2$ ($T_c$ = 38 K). In the normal state, the measured Knight shift and nuclear spin-lattice relaxation rate $(1/T_1)$ demonstrate the development of wave-number ($q$)-dependent spin fluctuations,

Hongjun Xiang, Erjun Kan, Su-Huai Wei, Myung-Hwan Whangbo

It is a challenge to synthesize graphene nanoribbons (GNRs) with narrow widths and smooth edges in large scale. Our first principles study on the hydrogenation of GNRs shows that the hydrogenation starts from the edges of GNRs and proceeds gradually toward the middle of the GNRs so as to maximize the number of carbon-carbon $π$-$π$ bonds. Furthermore, the pa

P. Rovillain, M. Cazayous, Y. Gallais, A. Sacuto

Raman scattering measurements on BiFeO3 single crystals show an important coupling between the magnetic order and lattice vibrations. The temperature evolution of phonons shows that the lowest energy E and A1 phonon modes are coupled to the spin order up to the Neel temperature. Furthermore, low temperature anomalies associated with the spin re-orientation a

Donald Yau

Motivated by recent work on Hom-Lie algebras and the Hom-Yang-Baxter equation, we introduce a twisted generalization of the classical Yang-Baxter equation (CYBE), called the classical Hom-Yang-Baxter equation (CHYBE). We show how an arbitrary solution of the CYBE induces multiple infinite families of solutions of the CHYBE. We also introduce the closely rela

R. de la Fuente Marcos, C. de la Fuente Marcos

Hierarchical star formation leads to a progressive decrease in the clustering of star clusters both in terms of spatial scale and age. Consistently, the statistical analysis of positions and ages of clusters in the Milky Way disk strongly suggests that a correlation between the duration of star formation in a region and its size does exist. The average age d

Bertrand Berche, Malte Henkel, Ralph Kenna

Critical phenomena were discovered by Cagniard de la Tour in 1822, who died 150 years ago. In order to mark this anniversary, the context and the early history of his discovery is reviewed. We then follow with a brief sketch of the history of critical phenomena, indicating the main lines of development until the present date. Os fenómenos cr\&#39;ıticos fora

Brent Kerby, Emma Turner

We consider the question: When do two finite abelian groups have isomorphic lattices of characteristic subgroups? An explicit description of the characteristic subgroups of such groups enables us to give a complete answer to this question in the case where at least one of the groups has odd order. An &#34;exceptional&#34; isomorphism, which occurs between th

Paul Cuff, Han-I Su, Abbas El Gamal

We investigate distributed source coding of two correlated sources X and Y where messages are passed to a decoder in a cascade fashion. The encoder of X sends a message at rate R_1 to the encoder of Y. The encoder of Y then sends a message to the decoder at rate R_2 based both on Y and on the message it received about X. The decoder&#39;s task is to estimate

Marcin Bilski

Let $X$ be an analytic subset of $U\times C^n$ of pure dimension $k$ such that the projection of $X$ onto $U$ is a proper mapping, where $U$ is a Runge domain in $C^k$. We show that $X$ can be approximated by algebraic sets.

E. L. Starostin, G. H. M. van der Heijden

We consider geometric variational problems for a functional defined on a curve in three-dimensional space. The functional is assumed to be written in a form invariant under the group of Euclidean motions. We present the Euler-Lagrange equations as equilibrium equations for the internal force and moment. Classical as well as new examples are discussed to illu

Emil Schwab

We describe three transfer functors P, P&#39;, P&#34; of an inverse exact category which arise from three transfer functions. We concentrate on some of the basic results which emerge from the theory of projections in inverse exact categories.

Cyrille Marquet

I discuss the role played by multiple partonic interactions (MPI) in the early stages of relativistic heavy-ion collisions, for which a weak-coupling QCD description is possible. From the Color Glass Condensate, through the Glasma and into the Quark-Gluon-Plasma phase, MPI are at the origin of interesting novel QCD phenomena.

Ketino Kaadze

In this article we describe the methods of observing WZ signal at CMS experiment at Large Hadron Collider. To reduce the dependence on Monte Carlo simulation we use data-driven techniques and estimate that 5sigma significance of WZ signal can be reached with less than 350 pb^{-1} at 95% C.L. for sqrt{s} = 14 TeV. We also overview several models that would yi

N. V. Petrovskaya, M. Yu. Zhukov

The two-dimensional flow of viscous incompressible fluid in the domain between two concentric circles is investigated numerically. To solve the problem, the low-order Galerkin models are used. When the inner circle rotates fast enough, two axially asymmetric flow regimes are observed. Both regimes are the stationary flows precessing in azimuthal direction. F

A J Williams, T M McQueen, V Ksenofontov, C Felser

Iron Selenide, Fe1.01Se, the layered parent compound of the recently discovered superconducting arsenide family, has previously been shown to be non magnetic and superconducting with a critical temperature of 8 K. Here we show that copper can be substituted at the iron site in Fe1.01Se up to a solubility limit of 20-30 %, after which a first order transition

Jorge Melendez, Judy Cohen

High-resolution (R ~ 100 000), high signal-to-noise spectra of M71 giants have been obtained with HIRES at the KeckI Telescope in order to measure their Mg isotopic ratios, as well as elemental abundances of C, N, O, Na, Mg, Al, Si, Ca, Ti, Ni, Zr and La. We demonstrate that M71 has two populations, the first having weak CN, normal O, Na, Mg, and Al, and a l

V. R. Shaginyan, M. Ya. Amusia, K. G. Popov

Low-temperature specific-heat measurements on YbRh2Si2 at the second order antiferromagnetic (AF) phase transition reveal a sharp peak at TN=72 mK. The corresponding critical exponent alpha turns out to be alpha=0.38, which differs significantly from that obtained within the framework of the fluctuation theory of second order phase transitions based on the s