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2007-12-01
On Myopic Sensing for Multi-Channel Opportunistic Access: Structure, Optimality, and Performance
We consider a multi-channel opportunistic communication system where the states of these channels evolve as independent and statistically identical Markov chains (the Gilbert-Elliot channel model). A user chooses one channel to sense and access in each slot and collects a reward determined by the state of the chosen ch...
0712.0035v3
2007-12-12
Two-connected graphs with prescribed three-connected components
We adapt the classical 3-decomposition of any 2-connected graph to the case of simple graphs (no loops or multiple edges). By analogy with the block-cutpoint tree of a connected graph, we deduce from this decomposition a bicolored tree tc(g) associated with any 2-connected graph g, whose white vertices are the 3-compon...
0712.1869v2
2008-03-13
Optimal spatial transportation networks where link-costs are sublinear in link-capacity
Consider designing a transportation network on $n$ vertices in the plane, with traffic demand uniform over all source-destination pairs. Suppose the cost of a link of length $\ell$ and capacity $c$ scales as $\ell c^\beta$ for fixed $0<\beta<1$. Under appropriate standardization, the cost of the minimum cost Gilbert ne...
0803.2037v1
2008-03-24
Was the Andromeda Stream Produced by a Disk Galaxy?
The halo region of M31 exhibits a startling level of stellar inhomogeneities, the most prominent of which is the "giant southern stream". Our previous analysis indicates that this stream, as well as several other observed features, are products of the tidal disruption of a single satellite galaxy with stellar mass ~10^...
0803.3476v2
2008-04-23
Geometric dynamics of Vlasov kinetic theory and its moments
The Vlasov equation of kinetic theory is introduced and the Hamiltonian structure of its moments is presented. Then we focus on the geodesic evolution of the Vlasov moments. As a first step, these moment equations generalize the Camassa-Holm equation to its multi-component version. Subsequently, adding electrostatic fo...
0804.3676v1
2008-05-05
On Expanded Cyclic Codes
The paper has a threefold purpose. The first purpose is to present an explicit description of expanded cyclic codes defined in $\GF(q^m)$. The proposed explicit construction of expanded generator matrix and expanded parity check matrix maintains the symbol-wise algebraic structure and thus keeps many important original...
0805.0615v2
2008-05-14
Path Diversity over Packet Switched Networks: Performance Analysis and Rate Allocation
Path diversity works by setting up multiple parallel connections between the end points using the topological path redundancy of the network. In this paper, \textit{Forward Error Correction} (FEC) is applied across multiple independent paths to enhance the end-to-end reliability. Network paths are modeled as erasure Gi...
0805.2185v1
2008-06-25
HAT-P-9b: A Low Density Planet Transiting a Moderately Faint F star
We report the discovery of a planet transiting a moderately faint (V=12.3 mag) late F star, with an orbital period of 3.92289 +/- 0.00004 days. From the transit light curve and radial velocity measurements we determine that the radius of the planet is R_p = 1.40 +/- 0.06 R_Jup and that the mass is M_p = 0.78 +/- 0.09 M...
0806.4008v2
2008-07-07
Micropropagation of three genotypes of Indian mustard [{Brassica juncea} (L.) Czern.] using seedling-derived transverse thin cell layer (tTCL) explants
Micropropagation of three genotypes of Indian mustard [\textit{Brassica juncea} (L.) Czern.] using 7-days old seedling-derived transverse thin cell layer (tTCL) explants was accomplished. The genotype, explant source and addition of silver nitrate to the medium significantly influenced shoot bud induction. MS medium ...
0807.1061v1
2008-07-18
On Probability Distributions for Trees: Representations, Inference and Learning
We study probability distributions over free algebras of trees. Probability distributions can be seen as particular (formal power) tree series [Berstel et al 82, Esik et al 03], i.e. mappings from trees to a semiring K . A widely studied class of tree series is the class of rational (or recognizable) tree series which ...
0807.2983v1
2008-11-02
Stretch-Twist torus dynamo in compact Riemannian manifolds
Earlier Arnold, Zeldovich, Ruzmaikin and Sokoloff [\textbf{JETP (1982)}] have computed the eigenvalue of a uniform stretching torus transformation which result on the first Riemann metric solution of the dynamo action problem. Recently some other attempts to obtain Riemann metrics representing dynamo action through con...
0811.0142v1
2008-11-21
Geodesic dynamo chaotic flows and non-Anosov maps in twisted magnetic flux tubes
Recently Tang and Boozer [{\textbf{Phys. Plasmas (2000)}}], have investigated the anisotropies in magnetic field dynamo evolution, from local Lyapunov exponents, giving rise to a metric tensor, in the Alfven twist in magnetic flux tubes (MFTs). Thiffeault and Boozer [\textbf{Chaos}(2001)] have investigated the how the ...
0811.3630v1
2008-12-03
Gravitino Dark Matter and the Cosmic Lithium Abundances
Supersymmetric extensions of the standard model of particle physics assuming the gravitino to be the lightest supersymmetric particle (LSP), and with the next-to-LSP decaying to the gravitino during Big Bang nucleosynthesis, are analyzed. Particular emphasis is laid on their potential to solve the "Li7 problem", an app...
0812.0788v2
2009-01-26
A Bayesian framework for estimating vaccine efficacy per infectious contact
In vaccine studies for infectious diseases such as human immunodeficiency virus (HIV), the frequency and type of contacts between study participants and infectious sources are among the most informative risk factors, but are often not adequately adjusted for in standard analyses. Such adjustment can improve the assessm...
0901.4025v1
2009-01-28
Theoretical characterization of a model of aragonite crystal orientation in red abalone nacre
Nacre, commonly known as mother-of-pearl, is a remarkable biomineral that in red abalone consists of layers of 400-nm thick aragonite crystalline tablets confined by organic matrix sheets, with the $(001)$ crystal axes of the aragonite tablets oriented to within $\pm$ 12 degrees from the normal to the layer planes. Rec...
0901.4482v1
2009-02-07
Partially-erupting prominences: a comparison between observations and model-predicted observables
AIM: To investigate several partially-erupting prominences to study their relationship with other CME-associated phenomena and to compare these observations with observables predicted by a model of partially-expelled flux ropes (Gibson & Fan, 2006a, b). METHODS: We have studied 6 selected events with partially-erupti...
0902.1228v1
2009-03-03
Proportional hazards models with continuous marks
For time-to-event data with finitely many competing risks, the proportional hazards model has been a popular tool for relating the cause-specific outcomes to covariates [Prentice et al. Biometrics 34 (1978) 541--554]. This article studies an extension of this approach to allow a continuum of competing risks, in which t...
0903.0487v1
2009-03-06
Five More Massive Binaries in the Cygnus OB2 Association
We present the orbital solutions for four OB spectroscopic binaries, MT145, GSC 03161-00815, 2MASS J20294666+4105083, and Schulte 73, and the partial orbital solution to the B spectroscopic binary, MT372, as part of an ongoing study to determine the distribution of orbital parameters for massive binaries in the Cygnus ...
0903.1265v1
2009-03-16
The Transit Light Curve Project. XII. Six Transits of the Exoplanet XO-2b
We present photometry of six transits of the exoplanet XO-2b. By combining the light-curve analysis with theoretical isochrones to determine the stellar properties, we find the planetary radius to be 0.996 +0.031/-0.018 rjup and the planetary mass to be 0.565 +/- 0.054 mjup. These results are consistent with those repo...
0903.2687v1
2009-03-19
Approximation of Bounds on Mixed Level Orthogonal Arrays
Mixed level orthogonal arrays are basic structures in experimental design. We develop three algorithms that compute Rao and Gilbert-Varshamov type bounds for mixed level orthogonal arrays. The computational complexity of the terms involved in these bounds can grow fast as the parameters of the arrays increase and this ...
0903.3438v2
2009-04-16
Good Concatenated Code Ensembles for the Binary Erasure Channel
In this work, we give good concatenated code ensembles for the binary erasure channel (BEC). In particular, we consider repeat multiple-accumulate (RMA) code ensembles formed by the serial concatenation of a repetition code with multiple accumulators, and the hybrid concatenated code (HCC) ensembles recently introduced...
0904.2482v1
2009-10-10
Multi-channel Opportunistic Access: A Case of Restless Bandits with Multiple Plays
This paper considers the following stochastic control problem that arises in opportunistic spectrum access: a system consists of n channels (Gilbert-Elliot channels)where the state (good or bad) of each channel evolves as independent and identically distributed Markov processes. A user can select exactly k channels to ...
0910.1954v1
2010-03-12
Anosov branches of dynamo spectra in one dimensional plasmas
Recently Guenther et al the globally diagonalized ${\alpha}^{2}$ dynamo operator spectrum [J Phys A 2007) in mean field media, and its Krein space related perturbation theory [J Phys A 2006). Earlier, an example of fast dynamos in stretch shear and fold Anosov maps have been given by Gilbert [PRSA [1993)). In this pape...
1003.2482v1
2010-04-05
A Prograde, Low-Inclination Orbit for the Very Hot Jupiter WASP-3b
We present new spectroscopic and photometric observations of the transiting exoplanetary system WASP-3. Spectra obtained during two separate transits exhibit the Rossiter-McLaughlin (RM) effect and allow us to estimate the sky-projected angle between the planetary orbital axis and the stellar rotation axis, lambda = 3....
1004.0692v2
2010-06-09
NLTT 41135: a field M-dwarf + brown dwarf eclipsing binary in a triple system, discovered by the MEarth observatory
We report the discovery of an eclipsing companion to NLTT 41135, a nearby M5 dwarf that was already known to have a wider, slightly more massive common proper motion companion, NLTT 41136, at 2.4 arcsec separation. Analysis of combined-light and radial velocity curves of the system indicates that NLTT 41135B is a 31-34...
1006.1793v1
2010-09-28
Connectivity in Sub-Poisson Networks
We consider a class of point processes (pp), which we call {\em sub-Poisson}; these are pp that can be directionally-convexly ($dcx$) dominated by some Poisson pp. The $dcx$ order has already been shown useful in comparing various point process characteristics, including Ripley's and correlation functions as well as sh...
1009.5696v1
2010-10-23
Closure method for spatially averaged dynamics of particle chains
We study the closure problem for continuum balance equations that model mesoscale dynamics of large ODE systems. The underlying microscale model consists of classical Newton equations of particle dynamics. As a mesoscale model we use the balance equations for spatial averages obtained earlier by a number of authors: Mu...
1010.4832v1
2010-10-26
Dualities and Identities for Entanglement-Assisted Quantum Codes
The dual of an entanglement-assisted quantum error-correcting (EAQEC) code is the code resulting from exchanging the original code's information qubits with its ebits. To introduce this notion, we show how entanglement-assisted (EA) repetition codes and accumulator codes are dual to each other, much like their classica...
1010.5506v4
2010-11-12
Magnetization Dynamics, Bennett Clocking and Associated Energy Dissipation in Multiferroic Logic
It has been recently shown that multiferroic logic - where logic bits are encoded in the magnetization orientation of a nanoscale magnetostrictive layer elastically coupled to a piezoelectric layer - can be Bennett clocked with small electrostatic potentials of few tens of mV applied to the piezoelectric layer. The pot...
1011.2914v2
2010-12-30
One-dimensional Gromov minimal filling
The present paper opens a new branch in the theory of variational problems with branching extremals, the investigation of one-dimensional minimal fillings of finite pseudo-metric spaces. On the one hand, this problem is a one-dimensional version of a generalization of Gromov's minimal fillings problem to the case of st...
1101.0106v2
2011-02-02
Kepler Input Catalog: Photometric Calibration and Stellar Classification
We describe the photometric calibration and stellar classification methods used to produce the Kepler Input Catalog (KIC). The KIC is a catalog containing photometric and physical data for sources in the Kepler Mission field of view; it is used by the mission to select optimal targets. We derived atmospheric extinction...
1102.0342v2
2011-05-10
Interstellar Solid Hydrogen
We consider the possibility that solid molecular hydrogen is present in interstellar space. If so cosmic-rays and energetic photons cause ionisation in the solid leading to the formation of H6+. This ion is not produced by gas-phase reactions and its radiative transitions therefore provide a signature of solid H2 in th...
1105.1861v1
2011-05-12
The History of Star Formation in Galaxy Disks in the Local Volume as Measured by the ACS Nearby Galaxy Survey Treasury
We present a measurement of the age distribution of stars residing in spiral disks and dwarf galaxies. We derive a complete star formation history of the ~140 Mpc^3 covered by the volume-limited sample of galaxies in the Advanced Camera for Surveys (ACS) Nearby Galaxy Survey Treasury (ANGST). The total star formation r...
1105.2571v1
2011-06-30
Revisiting No-Scale Supergravity Inspired Scenarios: Updated Theoretical and Phenomenological Constraints
We consider no-scale inspired supergravity scenarios, where the gravitino mass and related soft supersymmetry-breaking parameters are determined dynamically by radiative corrections to an essentially flat tree-level potential in the supersymmetry breaking hidden sector. We examine the theoretical and phenomenological v...
1106.6325v2
2012-02-21
Making Evildoers Pay: Resource-Competitive Broadcast in Sensor Networks
Consider a time-slotted, single-hop, wireless sensor network (WSN) consisting of n correct devices and and t=f*n Byzantine devices where f>=0 is any constant; that is, the Byzantine devices may outnumber the correct ones. There exists a trusted sender Alice who wishes to deliver a message m over a single channel to the...
1202.4576v4
2012-03-28
Bispectrum of the Sunyaev-Zel'dovich Effect
We perform a detailed study of the bispectrum of the Sunyaev-Zel'dovich effect. Using an analytical model for the pressure profiles of the intracluster medium, we demonstrate the SZ bispectrum to be a sensitive probe of the amplitude of the matter power spectrum parameter sigma_8. We find that the bispectrum amplitude ...
1203.6368v3
2012-05-01
A quasi-analytical model for energy-delay-reliability tradeoff studies during write operations in perpendicular STT-RAM cell
One of the biggest challenges the current STT-RAM industry faces is maintaining a high thermal stability while trying to switch within a given voltage pulse and energy cost. In this paper, we present a physics based analytical model that uses a modified Simmons' tunneling expression to capture the spin dependent tunnel...
1205.0183v1
2012-05-16
Transients in porous media: asymptotic time-domain Green functions and limits of current frequency-domain models
Time domain responses of porous media have been studied by some authors, but generally the possible descriptions have been given in the frequency domain. The aim of this paper, limited to materials with rigid skeleton considered as equivalent fluids, is to compare the descriptions by Johnson-Allard ($JA$%) as well as b...
1205.3775v2
2012-05-20
Externally-driven transformations of vortex textures in flat submicrometer magnets
Two effects of oscillatory transformations of vortex textures in flat nanomagnets due to the application of an external field or a spin-polarized electric current are analytically described with relevance to soft-magnetic structures of submicrometer sizes (whose thickness is significantly bigger than the magnetostatic ...
1205.5008v1
2012-06-11
Multi-Gigabit Wireless data transfer at 60 GHz
In this paper we describe the status of the first prototype of the 60 GHz wireless Multi-gigabit data transfer topology currently under development at University of Heidelberg using IBM 130 nm SiGe HBT BiCMOS technology. The 60 GHz band is very suitable for high data rate and short distance applications as for example ...
1206.2287v1
2012-06-14
On the Interpretation of the Foundations of Quantum Mechanics
This study discusses the quantum behavior of a particle, which is controlled by fluctuations in the physical space-time (ST) variables, rather than provides a novel interpretation of quantum theory. The fluctuations, i.e., inhomogeneities in a homogeneous phase ST, are prescribed by their probability. They determine th...
1206.2998v1
2012-08-08
RMR-Efficient Randomized Abortable Mutual Exclusion
Recent research on mutual exclusion for shared-memory systems has focused on "local spin" algorithms. Performance is measured using the "remote memory references" (RMRs) metric. As common in recent literature, we consider a standard asynchronous shared memory model with N processes, which allows atomic read, write and ...
1208.1723v1
2012-08-16
QIRAL: A High Level Language for Lattice QCD Code Generation
Quantum chromodynamics (QCD) is the theory of subnuclear physics, aiming at mod- eling the strong nuclear force, which is responsible for the interactions of nuclear particles. Lattice QCD (LQCD) is the corresponding discrete formulation, widely used for simula- tions. The computational demand for the LQCD is tremendou...
1208.4035v1
2012-08-22
Entanglement Spectrum Classification of $C_n$-invariant Noninteracting Topological Insulators in Two Dimensions
We study the single particle entanglement spectrum in 2D topological insulators which possess $n$-fold rotation symmetry. By defining a series of special choices of subsystems on which the entanglement is calculated, or real space cuts, we find that the number of protected in-gap states for each type of these real spac...
1208.4603v1
2012-09-25
Multiscale modeling in micromagnetics: existence of solutions and numerical integration
Various applications ranging from spintronic devices, giant magnetoresistance sensors, and magnetic storage devices, include magnetic parts on very different length scales. Since the consideration of the Landau-Lifshitz-Gilbert equation (LLG) constrains the maximum element size to the exchange length within the media, ...
1209.5548v2
2012-10-05
Rapid Size-Controlled Synthesis of Dextran-Coated, 64Cu-Doped Iron Oxide Nanoparticles
Research into developing dual modality probes enabled for magnetic resonance imaging (MRI) and positron emission tomography (PET) has been on the rise recently due to the potential to combine the high resolution of MRI and the high sensitivity of PET. Current synthesis techniques for developing multimodal probes is lar...
1210.1823v1
2012-10-05
Rapid Microwave-Assisted Synthesis of Dextran-Coated Iron Oxide Nanoparticles for Magnetic Resonance Imaging
Currently, magnetic iron oxide nanoparticles are the only nano-sized magnetic resonance imaging (MRI) contrast agents approved for clinical use, yet commercial manufacturing of these agents has been limited or discontinued. Though there is still widespread demand for these particles both for clinical use and research, ...
1210.1827v1
2012-10-16
Dark Matter Substructure Detection Using Spatially Resolved Spectroscopy of Lensed Dusty Galaxies
We investigate how strong lensing of dusty, star-forming galaxies by foreground galaxies can be used as a probe of dark matter halo substructure. We find that spatially resolved spectroscopy of lensed sources allows dramatic improvements to measurements of lens parameters. In particular we find that modeling of the ful...
1210.4562v1
2012-10-22
Shared Information -- New Insights and Problems in Decomposing Information in Complex Systems
How can the information that a set ${X_{1},...,X_{n}}$ of random variables contains about another random variable $S$ be decomposed? To what extent do different subgroups provide the same, i.e. shared or redundant, information, carry unique information or interact for the emergence of synergistic information? Recentl...
1210.5902v1
2012-10-23
Lensing Noise in mm-wave Galaxy Cluster Surveys
We study the effects of gravitational lensing by galaxy clusters of the background of dusty star-forming galaxies (DSFGs) and the Cosmic Microwave Background (CMB), and examine the implications for Sunyaev-Zel'dovich-based (SZ) galaxy cluster surveys. At the locations of galaxy clusters, gravitational lensing modifies ...
1210.6354v1
2012-10-29
Spin-Transfer Torque Magnetization Reversal in Uniaxial Nanomagnets with Thermal Noise
We consider the general Landau-Lifshitz-Gilbert (LLG) dynamical theory underlying the magnetization switching rates of a thin film uniaxial magnet subject to spin-torque effects and thermal fluctuations (thermal noise). After discussing the various dynamical regimes governing the switching phenomena, we present analyti...
1210.7675v3
2012-12-06
Splittings and automorphisms of relatively hyperbolic groups
We study automorphisms of a relatively hyperbolic group G. When G is one-ended, we describe Out(G) using a preferred JSJ tree over subgroups that are virtually cyclic or parabolic. In particular, when G is toral relatively hyperbolic, Out(G) is virtually built out of mapping class groups and subgroups of GL_n(Z) fixing...
1212.1434v3
2013-01-23
Localization, metabelian groups, and the isomorphism problem
If G and H are finitely generated, residually nilpotent metabelian groups, H is termed para-G if there is a homomorphism of G into H which induces an isomorphism between the corresponding terms of their lower central quotient groups. We prove that this is an equivalence relation. It is a much coarser relation than isom...
1301.5533v2
2013-01-26
Crystal nucleation and near-epitaxial growth in nacre
Nacre is a layered, iridescent lining found inside many mollusk shells, with a unique brick-and-mortar periodic structure at the sub-micron scale, and remarkable resistance to fracture. Despite extensive studies, it remains unclear how nacre forms. Here we present 20-nm, 2{\deg}-resolution Polarization-dependent Imagin...
1301.6273v2
2013-02-03
A generalization of variable elimination for separable inverse problems beyond least squares
In linear inverse problems, we have data derived from a noisy linear transformation of some unknown parameters, and we wish to estimate these unknowns from the data. Separable inverse problems are a powerful generalization in which the transformation itself depends on additional unknown parameters and we wish to determ...
1302.0441v2
2013-04-05
City versus wetland: Predicting urban growth in the Vecht area with a cellular automaton model
There are many studies dealing with the protection or restoration of wetlands and the sustainable economic growth of cities as separate subjects. This study investigates the conflict between the two in an area where city growth is threatening a protected wetland area. We develop a stochastic cellular automaton model fo...
1304.1609v1
2013-04-22
Topological Insulators with Commensurate Antiferromagnetism
We study the topological features of non-interacting insulators subject to an antiferromangetic (AFM) Zeeman field, or AFM insulators, the period of which is commensurate with the lattice period. These insulators can be classified by the presence/absence of an emergent anti-unitary symmetry: the combined operation of t...
1304.6081v3
2013-05-17
Spectral gap for stochastic energy exchange model with nonuniformly positive rate function
We give a lower bound on the spectral gap for a class of stochastic energy exchange models. In 2011, Grigo et al. introduced the model and showed that, for a class of stochastic energy exchange models with a uniformly positive rate function, the spectral gap of an $N$-component system is bounded from below by a functio...
1305.4066v3
2013-08-18
Layered Constructions for Low-Delay Streaming Codes
We propose a new class of error correction codes for low-delay streaming communication. We consider an online setup where a source packet arrives at the encoder every $M$ channel uses, and needs to be decoded with a maximum delay of $T$ packets. We consider a sliding-window erasure channel --- $\cC(N,B,W)$ --- which in...
1308.3827v1
2013-08-31
Delay Minimization for Instantly Decodable Network Coding in Persistent Channels with Feedback Intermittence
In this paper, we consider the problem of minimizing the multicast decoding delay of generalized instantly decodable network coding (G-IDNC) over persistent forward and feedback erasure channels with feedback intermittence. In such an environment, the sender does not always receive acknowledgement from the receivers af...
1309.0145v2
2013-09-06
Energy release from impacting prominence material following the 2011 June 7 eruption
Solar filaments exhibit a range of eruptive-like dynamic activity, ranging from the full or partial eruption of the filament mass and surrounding magnetic structure as a coronal mass ejection (CME), to a fully confined or 'failed' eruption. On 2011 June 7, a dramatic partial eruption of a filament was observed by multi...
1309.1769v1
2013-09-26
Constraints on a second planet in the WASP-3 system
There have been previous hints that the transiting planet WASP-3 b is accompanied by a second planet in a nearby orbit, based on small deviations from strict periodicity of the observed transits. Here we present 17 precise radial velocity measurements and 32 transit light curves that were acquired between 2009 and 2011...
1309.6733v1
2013-09-28
Synthetic Multiferroic Interconnects for Magnetic Logic Circuits
In this work, we consider the possibility of using synthetic multiferroics comprising piezoelectric and magnetostrictive materials as an interconnect for nano magnetic logic circuits. The proposed interconnect resembles a parallel plate capacitor filled with a piezoelectric, where one of the plates is made of a magneto...
1309.7399v1
2013-10-01
Ionized Plasma and Neutral Gas Coupling in the Sun's Chromosphere and Earth's Ionosphere/Thermosphere
We review our understanding of ionized plasma and neutral gas coupling in the weakly ionized, stratified, electromagnetically-permeated regions of the Sun's chromosphere and Earth's ionosphere/thermosphere. Using representative models for each environment we derive fundamental descriptions of the coupling of the consti...
1310.0405v4
2013-11-13
Excitation of radial collective modes in a quantum dot: Beyond linear response
We compare the response of five different models of two interacting electrons in a quantum dot to an external short lived radial excitation that is strong enough to excite the system well beyond the linear response regime. The models considered describe the Coulomb interaction between the electrons in different ways ra...
1311.3252v2
2013-11-20
Neutron-induced dpa, transmutations, gas production, and helium embrittlement of fusion materials
In a fusion reactor materials will be subjected to significant fluxes of high-energy neutrons. As well as causing radiation damage, the neutrons also initiate nuclear reactions leading to changes in the chemical composition of materials (transmutation). Many of these reactions produce gases, particularly helium, which ...
1311.5079v1
2013-12-19
The availability of research data declines rapidly with article age
Policies ensuring that research data are available on public archives are increasingly being implemented at the government [1], funding agency [2-4], and journal [5,6] level. These policies are predicated on the idea that authors are poor stewards of their data, particularly over the long term [7], and indeed many stud...
1312.5670v1
2014-01-13
On List-decodability of Random Rank Metric Codes
In the present paper, we consider list decoding for both random rank metric codes and random linear rank metric codes. Firstly, we show that, for arbitrary $0<R<1$ and $\epsilon>0$ ($\epsilon$ and $R$ are independent), if $0<\frac{n}{m}\leq \epsilon$, then with high probability a random rank metric code in $F_{q}^{m\ti...
1401.2693v2
2014-01-30
Quantitative Decoding of Interactions in Tunable Nanomagnet Arrays Using First Order Reversal Curves
To develop a full understanding of interactions in nanomagnet arrays is a persistent challenge, critically impacting their technological acceptance. This paper reports the experimental, numerical and analytical investigation of interactions in arrays of Co nanoellipses using the first-order reversal curve (FORC) techni...
1401.7749v1
2014-02-07
For-all Sparse Recovery in Near-Optimal Time
An approximate sparse recovery system in $\ell_1$ norm consists of parameters $k$, $\epsilon$, $N$, an $m$-by-$N$ measurement $\Phi$, and a recovery algorithm, $\mathcal{R}$. Given a vector, $\mathbf{x}$, the system approximates $x$ by $\widehat{\mathbf{x}} = \mathcal{R}(\Phi\mathbf{x})$, which must satisfy $\|\widehat...
1402.1726v2
2014-03-11
Measuring the power spectrum of dark matter substructure using strong gravitational lensing
In recent years, it has become possible to detect individual dark matter subhalos near images of strongly lensed extended background galaxies. Typically, only the most massive subhalos in the strong lensing region may be detected this way. In this work, we show that strong lenses may also be used to constrain the much ...
1403.2720v3
2014-03-14
Cosmological Spectral Deconvolution
One of the main goals of modern observational cosmology is to map the large scale structure of the Universe. A potentially powerful approach for doing this would be to exploit three-dimensional spectral maps, i.e. the specific intensity of extragalactic light as a function of wavelength and direction on the sky, to mea...
1403.3727v1
2014-03-27
On the Performance of Short Block Codes over Finite-State Channels in the Rare-Transition Regime
As the mobile application landscape expands, wireless networks are tasked with supporting different connection profiles, including real-time traffic and delay-sensitive communications. Among many ensuing engineering challenges is the need to better understand the fundamental limits of forward error correction in non-as...
1403.7232v1
2014-04-08
Cost-oblivious storage reallocation
Databases need to allocate and free blocks of storage on disk. Freed blocks introduce holes where no data is stored. Allocation systems attempt to reuse such deallocated regions in order to minimize the footprint on disk. If previously allocated blocks cannot be moved, the problem is called the memory allocation proble...
1404.2019v3
2014-04-14
Magneto-photonic phenomena at terahertz frequencies
Magneto-terahertz phenomena are the main focus of the thesis. This work started as supporting research for the science of an X-ray laser (SwissFEL). X-ray lasers have recently drawn great attention as an unprecedented tool for scientific research on the ultrafast scale..... To answer this fundamental question, we perfo...
1404.3764v1
2014-05-13
The Star Formation Histories of Local Group Dwarf Galaxies II. Searching For Signatures of Reionization
We search for signatures of reionization in the star formation histories (SFHs) of 38 Local Group dwarf galaxies (10$^4$ $<$ M$_{\star}$ $<$ 10$^9$ M$_{\odot}$). The SFHs are derived from color-magnitude diagrams using archival Hubble Space Telescope/Wide Field Planetary Camera 2 imaging. Only five quenched galaxies (A...
1405.3281v1
2014-05-26
Constraints for the Progenitor Masses of 17 Historic Core-Collapse Supernovae
Using resolved stellar photometry measured from archival HST imaging, we generate color-magnitude diagrams of the stars within 50 pc of the locations of historic core-collapse supernovae that took place in galaxies within 8 Mpc. We fit these color-magnitude distributions with stellar evolution models to determine the b...
1405.6626v1
2014-06-09
Calibrating CHIME, A New Radio Interferometer to Probe Dark Energy
The Canadian Hydrogen Intensity Mapping Experiment (CHIME) is a transit interferometer currently being built at the Dominion Radio Astrophysical Observatory (DRAO) in Penticton, BC, Canada. We will use CHIME to map neutral hydrogen in the frequency range 400 -- 800\,MHz over half of the sky, producing a measurement of ...
1406.2267v1
2014-07-10
Beating the Heat! Automated Characterization of Piezoelectric Tubes for Starbugs
The Australian Astronomical Observatory has extensively prototyped a new robotic positioner to allow simultaneous positioning of optical fibers at the focal plane called 'Starbugs'. The Starbug devices each consist of two concentric piezoelectric tubes that 'walk' the optical fiber over the focal plane to accuracy of s...
1407.2681v1
2014-07-16
TriAnd and its Siblings: Satellites of Satellites in the Milky Way Halo
We explore the Triangulum-Andromeda (TriAnd) overdensity in the SPLASH (Spectroscopic and Photometric Landscape of Andromeda's Stellar Halo) and SEGUE (the Sloan Extension for Galactic Understanding and Exploration) spectroscopic surveys. Milky Way main sequence turn-off stars in the SPLASH survey reveal that the TriAn...
1407.4458v2
2014-07-17
The Green's Function for the Hückel (Tight Binding) Model
Applications of the H\"uckel (tight binding) model are ubiquitous in quantum chemistry and solid state physics. The matrix representation of this model is isomorphic to an unoriented vertex adjacency matrix of a bipartite graph, which is also the Laplacian matrix plus twice the identity. In this paper, we analytically ...
1407.4780v4
2014-07-29
Formation of magnetic skyrmions with tunable properties in PdFe bilayer deposited on Ir(111)
We perform an extensive study of the spin-configurations in a PdFe bilayer on Ir(111) in terms of ab initio and spin-model calculations. We use the spin-cluster expansion technique to obtain spin model parameters, and solve the Landau-Lifshitz-Gilbert equations at zero temperature. In particular, we focus on effects of...
1407.7718v2
2014-08-14
Developing Structural, High-heat flux and Plasma Facing Materials for a near-term DEMO Fusion Power Plant: the EU Assessment
The findings of the EU 'Materials Assessment Group' (MAG), within the 2012 EU Fusion Roadmap exercise, are discussed. MAG analysed the technological readiness of structural, plasma facing and high heat flux materials for a DEMO concept to be constructed in the early 2030s, proposing a coherent strategy for R&D up to a ...
1408.3546v1
2014-08-26
Weedy adaptation in Setaria spp.: IX. Effects of salinity, temperature, light and seed dormancy on Setaria faberi seed germination
Life in salty habitats is a function of tolerance to those chemicals at all critical phases of a plant's life history. The ability to withstand salt as an established plant may require different mechanisms and plant traits than those needed to germinate in salty soils. Seeds establishing themselves in high salt content...
1408.6187v1
2014-09-02
Accessing Different Spin-Disordered States using First Order Reversal Curves
Combined first order reversal curve (FORC) analyses of the magnetization (M-FORC) and magnetoresistance (MR-FORC) have been employed to provide a comprehensive study of the M-MR correlation in two canonical systems: a NiFe/Cu/FePt pseudo spin-valve (PSV) and a [Co/Cu]8 multilayer. In the PSV, due to the large differenc...
1409.0825v1
2014-10-20
Momentum space imaging of Cooper pairing in a half-Dirac-gas topological superconductor (a helical 2D topological superconductor)
Superconductivity in Dirac electrons has recently been proposed as a new platform between novel concepts in high-energy and condensed matter physics. It has been proposed that supersymmetry and exotic quasiparticles, both of which remain elusive in particle physics, may be realized as emergent particles in superconduct...
1410.5405v1
2014-12-23
Dynamical symmetries of Markov processes with multiplicative white noise
We analyse various properties of stochastic Markov processes with multiplicative white noise. We take a single-variable problem as a simple example, and we later extend the analysis to the Landau-Lifshitz-Gilbert equation for the stochastic dynamics of a magnetic moment. In particular, we focus on the non-equilibrium t...
1412.7564v2
2015-01-09
Random Triangle Theory with Geometry and Applications
What is the probability that a random triangle is acute? We explore this old question from a modern viewpoint, taking into account linear algebra, shape theory, numerical analysis, random matrix theory, the Hopf fibration, and much much more. One of the best distributions of random triangles takes all six vertex coordi...
1501.03053v1
2015-02-03
The use of covariates and random effects in evaluating predictive biomarkers under a potential outcome framework
Predictive or treatment selection biomarkers are usually evaluated in a subgroup or regression analysis with focus on the treatment-by-marker interaction. Under a potential outcome framework (Huang, Gilbert and Janes [Biometrics 68 (2012) 687-696]), a predictive biomarker is considered a predictor for a desirable treat...
1502.00757v1
2015-02-03
The Blackhole-Dark Matter Halo Connection
We explore the connection between the central supermassive blackholes (SMBH) in galaxies and the dark matter halo through the relation between the masses of the SMBHs and the maximum circular velocities of the host galaxies, as well as the relationship between stellar velocity dispersion of the spheroidal component and...
1502.00775v1
2015-03-01
Computing in continuous space with self-assembling polygonal tiles
In this paper we investigate the computational power of the polygonal tile assembly model (polygonal TAM) at temperature 1, i.e. in non-cooperative systems. The polygonal TAM is an extension of Winfree's abstract tile assembly model (aTAM) which not only allows for square tiles (as in the aTAM) but also allows for tile...
1503.00327v2
2015-03-05
Nonparametric Bounds and Sensitivity Analysis of Treatment Effects
This paper considers conducting inference about the effect of a treatment (or exposure) on an outcome of interest. In the ideal setting where treatment is assigned randomly, under certain assumptions the treatment effect is identifiable from the observable data and inference is straightforward. However, in other settin...
1503.01598v1
2015-03-16
Dynamics of Current and Field Driven Domain Wall Motion under the Influence of Transverse Magnetic Field
The dynamics of transverse Neel domain wall in a ferromagnetic nanostrip in the presence of driving field, current and transverse magnetic field is investigated by the Landau-Lifshitz-Gilbert(LLG) equation with the adiabatic and non-adiabatic spin-transfer torques both analytically and numerically. The analytical expre...
1503.04560v2
2015-03-17
Single Hit Energy-resolved Laue Diffraction
In-situ white light Laue diffraction has been successfully used to interrogate the structure of single crystal materials undergoing rapid (nanosecond) dynamic compression up to megabar pressures. However, information on strain state accessible via this technique is limited, reducing its applicability for a range of app...
1503.05131v2
2015-03-24
No variations in transit times for Qatar-1 b
The transiting hot Jupiter planet Qatar-1 b was presented to exhibit variations in transit times that could be of perturbative nature. A hot Jupiter with a planetary companion on a nearby orbit would constitute an unprecedented planetary configuration, important for theories of formation and evolution of planetary syst...
1503.07191v1
2015-03-25
Rigorous numerical study of strong microwave photon-magnon coupling in all-dielectric magnetic multilayers
We demonstrate theoretically a strong local enhancement of the intensity of the in-plane microwave magnetic field in multilayered structures made from a magneto-insulating yttrium iron garnet (YIG) layer sandwiched between two non-magnetic layers with a high dielectric constant matching that of YIG. The enhancement is ...
1503.07282v1
2015-04-22
Thermally Driven Ratchet Motion of Skyrmion Microcrystal and Topological Magnon Hall Effect
Spontaneously emergent chirality is an issue of fundamental importance across the natural sciences. It has been argued that a unidirectional (chiral) rotation of a mechanical ratchet is forbidden in thermal equilibrium, but becomes possible in systems out of equilibrium. Here we report our finding that a topologically ...
1504.05860v1
2015-05-05
Evaluating the Potential of a Dual Randomized Kaczmarz Solver for Laplacian Linear Systems
A new method for solving Laplacian linear systems proposed by Kelner et al. involves the random sampling and update of fundamental cycles in a graph. Kelner et al. proved asymptotic bounds on the complexity of this method but did not report experimental results. We seek to both evaluate the performance of this approach...
1505.00875v3
2015-06-18
Area-Delay-Energy Tradeoffs of Strain-Mediated Multiferroic Devices
Multiferroic devices hold profound promise for ultra-low energy computing in beyond Moore's law era. The magnetization of a magnetostrictive shape-anisotropic single-domain nanomagnet strain-coupled with a piezoelectric layer in a multiferroic composite structure can be switched between its two stable states (separated...
1506.07859v1
2015-07-30
Confirmation of the Planetary Microlensing Signal and Star and Planet Mass Determinations for Event OGLE-2005-BLG-169
We present Hubble Space Telescope (HST) Wide Field Camera 3 (WFC3) observations of the source and lens stars for planetary microlensing event OGLE-2005-BLG-169, which confirm the relative proper motion prediction due to the planetary light curve signal observed for this event. This (and the companion Keck result) provi...
1507.08661v1