Population dynamics of the zebra mussel (Dreissena polymorpha) in the Hudson River: settlement and post-settlement processes

Submitted in partial fulfillment of contract requirements with NOAA, Semi-Annual Report - October 2004,Report issued on: October 2004INHS Technical Report for submission to: National Oceanic and Atmospheric Administration (NOAA

Light flavour hadron production in pp collisions at s\sqrt{s} = 13 TeV with ALICE

The ALICE detector has excellent Particle IDentification (PID) capabilities in the central barrel ($\lvert \eta \rvert <$ 0.9). This allows identified hadron production to be measured over a wide transverse momentum ($p_{\rm{T}}$) range, using different sub-detectors and techniques: their specific energy loss (d$E$/d$x$), the velocity determination via time-of-flight measurement, the Cherenkov angle or their characteristic weak decay topology. Results on identified light flavour hadron production at mid-rapidity measured by ALICE in proton-proton collisions at $\sqrt{s}$ = 13 TeV are presented and compared with previous measurements performed at lower energies. The results cover a wide range of particle species including long-lived hadrons, resonances and multi-strange baryons over the $p_{\rm{T}}$ range from 150 MeV/$c$ up to 20 GeV/$c$, depending on the particle species.Comment: 4 pages, 4 figures, Proceedings of Hot Quarks September 12-17, 2016, South Padre Island, Texas, US

Partitioning 22-coloured complete kk-uniform hypergraphs into monochromatic ℓ\ell-cycles

We show that for all $\ell, k, n$ with $\ell \leq k/2$ and $(k-\ell)$ dividing $n$ the following hypergraph-variant of Lehel's conjecture is true. Every $2$-edge-colouring of the $k$-uniform complete hypergraph $\mathcal{K}_n^{(k)}$ on $n$ vertices has at most two disjoint monochromatic $\ell$-cycles in different colours that together cover all but at most $4(k-\ell)$ vertices. If $\ell \leq k/3$, then at most two $\ell$-cycles cover all but at most $2(k-\ell)$ vertices. Furthermore, we can cover all vertices with at most $4$ ($3$ if $\ell\leq k/3$) disjoint monochromatic $\ell$-cycles.Comment: 14 pages, 2 figure

Precession and Recession of the Rock'n'roller

We study the dynamics of a spherical rigid body that rocks and rolls on a plane under the effect of gravity. The distribution of mass is non-uniform and the centre of mass does not coincide with the geometric centre. The symmetric case, with moments of inertia I_1=I_2, is integrable and the motion is completely regular. Three known conservation laws are the total energy E, Jellett's quantity Q_J and Routh's quantity Q_R. When the inertial symmetry I_1=I_2 is broken, even slightly, the character of the solutions is profoundly changed and new types of motion become possible. We derive the equations governing the general motion and present analytical and numerical evidence of the recession, or reversal of precession, that has been observed in physical experiments. We present an analysis of recession in terms of critical lines dividing the (Q_R,Q_J) plane into four dynamically disjoint zones. We prove that recession implies the lack of conservation of Jellett's and Routh's quantities, by identifying individual reversals as crossings of the orbit (Q_R(t),Q_J(t)) through the critical lines. Consequently, a method is found to produce a large number of initial conditions so that the system will exhibit recession

Calamares de la familia Onychoteuthidae Gray, 1847 en el Océano Pacífico suroriental

Indexación: Web of ScienceHooked squids (Family Onychoteuthidae Gray, 1847) inhabit all oceans of the world except the Arctic. This family is currently comprised of 25 species belonging to seven genera. In the southeastern Pacific Ocean, approximately five onychoteuthid species have been previously identified, but true identity of these taxa is uncertain. We reviewed museum collections, from Chile, United States and New Zealand, and literature to elucidate the presence of hooked squids in the southeastern Pacific Ocean. The present status of the Onychoteuthidae from the southeastern Pacific only includes four species: Onychoteuthis aequimanus, Onykia ingens, Onykia robsoni, and Kondakovia nigmatullini.RESUMEN. Los calamares ganchudos (Familia Onychoteuthidae Gray, 1847) habitan en todos los océanos excepto en el Ártico. Esta familia está compuesta actualmente de 25 especies pertenecientes a siete géneros. En el Océano Pacífico suroriental, aproximadamente cinco especies de Onychoteuthidae han sido identificadas previamente, pero su estatus taxonómico es incierto. Se revisaron las colecciones de museos de Chile, Estados Unidos y Nueva Zelanda, y la literatura para dilucidar la presencia de calamares con ganchos en el Pacífico suroriental. El estado actual de la familia Onychoteuthidae en esta área incluye solo cuatro especies: Onychoteuthis aequimanus, Onykia ingens, Onykia robsoni y Kondakovia nigmatullini.http://www.lajar.cl/pdf/imar/v44n2/Art%C3%ADculo_44_2_23.pd

A two-state kinetic model for the unfolding of single molecules by mechanical force

We investigate the work dissipated during the irreversible unfolding of single molecules by mechanical force, using the simplest model necessary to represent experimental data. The model consists of two levels (folded and unfolded states) separated by an intermediate barrier. We compute the probability distribution for the dissipated work and give analytical expressions for the average and variance of the distribution. To first order, the amount of dissipated work is directly proportional to the rate of application of force (the loading rate), and to the relaxation time of the molecule. The model yields estimates for parameters that characterize the unfolding kinetics under force in agreement with those obtained in recent experimental results (Liphardt, J., et al. (2002) {\em Science}, {\bf 296} 1832-1835). We obtain a general equation for the minimum number of repeated experiments needed to obtain an equilibrium free energy, to within $k_BT$, from non-equilibrium experiments using the Jarzynski formula. The number of irreversible experiments grows exponentially with the ratio of the average dissipated work, \bar{\Wdis}, to $k_BT$.}Comment: PDF file, 5 page

Complete classification of discrete resonant Rossby/drift wave triads on periodic domains

We consider the set of Diophantine equations that arise in the context of the barotropic vorticity equation on periodic domains, when nonlinear wave interactions are studied to leading order in the amplitudes. The solutions to this set of Diophantine equations are of interest in atmosphere (Rossby waves) and Tokamak plasmas (drift waves), because they provide the values of the spectral wavevectors that interact resonantly via three-wave interactions. These come in "triads", i.e., groups of three wavevectors. We provide the full solution to the Diophantine equations in the case of infinite Rossby deformation radius. The method is completely new, and relies on mapping the unknown variables to rational points on quadratic forms of "Minkowski" type. Classical methods invented centuries ago by Fermat, Euler, Lagrange and Minkowski, are used to classify all solutions to our original Diophantine equations, thus providing a computational method to generate numerically all the resonant triads in the system. Our method has a clear computational advantage over brute-force numerical search: on a 10000^2 grid, the brute-force search would take 15 years using optimised C++ codes, whereas our method takes about 40 minutes. The method is extended to generate quasi-resonant triads, which are defined by relaxing the resonant condition on the frequencies, allowing for a small mismatch. Quasi-resonances are robust with respect to physical perturbations, unlike exact resonances. Therefore, the new method is really valuable in practical terms. We show that the set of quasi-resonances form an intricate network of clusters of connected triads, whose structure depends on the value of the allowed mismatch. We provide some quantitative comparison between the clusters' structure and the onset of fully nonlinear turbulence in the barotropic vorticity equation, and provide perspectives for new research.Comment: Improved version, accepted in Commun. Nonlinear Sci. Numer. Simula