JPEG2000 Image Compression on Solar EUV Images

For future solar missions as well as ground-based telescopes, efficient ways to return and process data have become increasingly important. Solar Orbiter, e.g., which is the next ESA/NASA mission to explore the Sun and the heliosphere, is a deep-space mission, which implies a limited telemetry rate that makes efficient onboard data compression a necessity to achieve the mission science goals. Missions like the Solar Dynamics Observatory (SDO) and future ground-based telescopes such as the Daniel K. Inouye Solar Telescope, on the other hand, face the challenge of making petabyte-sized solar data archives accessible to the solar community. New image compression standards address these challenges by implementing efficient and flexible compression algorithms that can be tailored to user requirements. We analyse solar images from the Atmospheric Imaging Assembly (AIA) instrument onboard SDO to study the effect of lossy JPEG2000 (from the Joint Photographic Experts Group 2000) image compression at different bit rates. To assess the quality of compressed images, we use the mean structural similarity (MSSIM) index as well as the widely used peak signal-to-noise ratio (PSNR) as metrics and compare the two in the context of solar EUV images. In addition, we perform tests to validate the scientific use of the lossily compressed images by analysing examples of an on-disk and off-limb coronal-loop oscillation time-series observed by AIA/SDO.Comment: 25 pages, published in Solar Physic

Chromosome Evolution in New World Monkeys (Platyrrhini)

During the last decades, New World monkey (NWM, Platyrrhini, Anthropoideae) comparative cytogenetics has shed light on many fundamental aspects of genome organisation and evolution in this fascinating, but also highly endangered group of neotropical primates. In this review, we first provide an overview about the evolutionary origin of the inferred ancestral NWM karyotype of 2n = 54 chromosomes and about the lineage-specific chromosome rearrangements resulting in the highly divergent karyotypes of extant NWM species, ranging from 2n = 16 in a titi monkey to 2n = 62 in a woolly monkey. Next, we discuss the available data on the chromosome phylogeny of NWM in the context of recent molecular phylogenetic analyses. In the last part, we highlight some recent research on the molecular mechanisms responsible for the large-scale evolutionary genomic changes in platyrrhine monkeys. Copyright (C) 2012 S. Karger AG, Base

Mesoscopic scattering of spin s particles

Quantum effects in weakly disordered systems are governed by the properties of the elementary interaction between propagating particles and impurities. Long range mesoscopic effects due to multiple scattering are derived by iterating the single scattering vertex, which has to be appropriately diagonalized. In the present contribution, we present a systematic and detailed diagonalisation of the diffuson and cooperon vertices responsible for weak localisation effects. We obtain general expressions for eigenvalues and projectors onto eigenmodes, for any spin and arbitrary elementary interaction with impurities. This description provides a common frame for a unified theory of mesoscopic spin physics for electrons, photons, and other quantum particles. We treat in detail the case of spin-flip scattering of electrons by freely orientable magnetic impurities and briefly review the case of photon scattering from degenerate dipole transitions in cold atomic gases.Comment: published version, with a new figure and new section

Symmetries and Triplet Dispersion in a Modified Shastry-Sutherland Model for SrCu_2(BO_3)_2

We investigate the one-triplet dispersion in a modified Shastry-Sutherland Model for SrCu_2(BO_3)_2 by means of a series expansion about the limit of strong dimerization. Our perturbative method is based on a continuous unitary transformation that maps the original Hamiltonian to an effective, energy quanta conserving block diagonal Hamiltonian H_{eff}. The dispersion splits into two branches which are nearly degenerated. We analyse the symmetries of the model and show that space group operations are necessary to explain the degeneracy of the dispersion at k=0 and at the border of the magnetic Brillouin zone. Moreover, we investigate the behaviour of the dispersion for small |k| and compare our results to INS data.Comment: 9 pages, 8 figures accepted by J. Phys.: Condens. Matte

Forage Preferences of Horses

In the northern climates the forage fed to horses has by tradition been hay. However, hay is subjected to moulding unless it is stored dry. Mould spores together with actinomycetes are responsible for the condition Recurrent Airway Obstruction (RAO), which is the second largest reason for culling of warm-blood horses in Sweden (Wallin, 2001). Therefore, the possibility of replacing hay with haylage and silage in the feed rations of horses is interesting. The objective of this study was to investigate the preferences among horses for different types of conserved grass, to gain more knowledge about the suitability of haylage and silage as a horse feed

A versatile plasma technique to improve plastic materials against gas and water-vapour permeation

Plasma-enhanced chemical deposition processes have been studied by comparing the performance of flexible diffusion barrier layers on plastic films produced in the same reactor. Under similar experimental conditions, a higher deposition rate is achieved by microwave discharges than by bipolar, pulsed d.c. magnetron sputtering processes. However, with both discharge modes, dense hydrocarbon coatings were produced, exhibiting a barrier improvement factor up to 120 and a flexibility ranging from 1.1%-8.8% before formation of microcracks started to dominate permeation characteristics. The density of the coatings is 1.0-1.6 g cm−3 and their hydrogen content varies from 23%-33

What can we learn from Dijet suppression at RHIC?

We present a systematic study of the dijet suppression at RHIC using the VNI/BMS parton cascade. We examine the modification of the dijet asymmetry A_j and the within-cone transverse energy distribution (jet-shape) along with partonic fragmentation distributions z and j_t in terms of: qhat; the path length of leading and sub-leading jets; cuts on the jet energy distributions; jet cone angle and the jet-medium interaction mechanism. We find that A_j is most sensitive to qhat and relatively insensitive to the nature of the jet-medium interaction mechanism. The jet profile is dominated by qhat and the nature of the interaction mechanism. The partonic fragmentation distributions clearly show the jet modification and differentiate between elastic and radiative+elastic modes

Charge and Magnetic Flux Correlations in Chern-Simons Theory with Fermions

Charge and magnetic flux bearing operators are introduced in Chern-Simons theory both in its pure form and when it is coupled to fermions. The magnetic flux creation operator turns out to be the Wilson line. The euclidean correlation functions of these operators are shown to be local and are evaluated exactly in the pure case and through an expansion in the inverse fermion mass whenever these are present. Physical states only occur in the presence of fermions and consist of composite charge-magnetic flux carrying states which are in general anyonic. The large distance behavior of the correlation functions indicates the condensation of charge and magnetic flux.Comment: Latex, 17 page

Reactions at polymer interfaces: A Monte Carlo Simulation

Reactions at a strongly segregated interface of a symmetric binary polymer blend are investigated via Monte Carlo simulations. End functionalized homopolymers of different species interact at the interface instantaneously and irreversibly to form diblock copolymers. The simulations, in the framework of the bond fluctuation model, determine the time dependence of the copolymer production in the initial and intermediate time regime for small reactant concentration $\rho_0 R_g^3=0.163 ... 0.0406$. The results are compared to recent theories and simulation data of a simple reaction diffusion model. For the reactant concentration accessible in the simulation, no linear growth of the copolymer density is found in the initial regime, and a $\sqrt{t}$-law is observed in the intermediate stage.Comment: to appear in Macromolecule