Magnetic fields in merging spirals - the Antennae

We present an extensive study of magnetic fields in a system of merging galaxies. We obtained for NGC4038/39 (the Antennae) radio total intensity and polarization maps at 8.44, 4.86 and 1.49GHz using the VLA in the C and D configurations. The radio thermal fraction was found to be about 50% at 10.45GHz, higher than in normal spirals. The mean total magnetic fields in both galaxies are about two times stronger (20microG) than in normal spirals. However,the degree of field regularity is rather low, implying tangling of the regular component in regions with interaction-enhanced star formation. Our data combined with those in HI, Halpha, X-rays and in far infrared allow us to study local interrelations between different gas phases and magnetic fields. We distinguish several radio-emitting regions with different physical properties and at various evolutionary stages. The whole overlapping region shows a coherent magnetic field structure, probably tracing the line of collision between the arms of merging spirals while the total radio emission reveals hidden star formation nests. The southern part of it is a particularly intense merger-triggered starburst. Highly tangled magnetic fields reach there strengths of 30microG, even larger than in both individual galaxies, possibly due to compression of the original fields pulled out from the parent disks. In the northeastern ridge, away from star-forming regions, the magnetic field is highly coherent with a strong regular component of 10microG tracing gas shearing motions along the tidal tail. Modelling Faraday rotation data show that we deal with a three-dimensionally curved structure of magnetic fields, becoming almost parallel to the sky plane in the southeastern part of the ridge.Comment: Accepted for publication in AA, 16 pages including 16 figures, high-res version at http://www.oa.uj.edu.pl/~chris/publ/4038.ps.g

Using software development progress data to understand threats to project outcomes

Peer reviewe

High-temperature synthesis, single-crystal X-ray and neutron powder diffraction, and materials properties of Sr3Ln10Si18Al12O18N36 (Ln = Ce, Pr, Nd)

The novel oxonitridoaluminosilicates (sialons) Sr3Ln10Si18Al12O18N36 (Ln = Ce, Pr, Nd) were obtained by the reaction of the respective lanthanide metals with Si(NH)2, SrCO3, and AlN using a radiofrequency furnace at temperatures between 1550–1650°C. The crystal structures of the isotypic sialons were determined by single-crystal X-ray investigations (Sr3Ce10Si18Al12O18N36: I3m, Z = 2, a = 1338.2(2) pm, R1 = 0.0333; Sr3Pr10Si18Al12O18N36: a = 1334.54(6) pm, R1 = 0.0296; Sr3Nd10Si18Al12O18N36: a = 1332.85(6) pm, R1 = 0.0271) and in the case of Sr3Pr10Si18Al12O18N36 with powder neutron diffraction as well. The three-dimensional sialon network is built up by SiON3, SiN4, and AlON3 tetrahedra. Besides the bridging O and N atoms of the sialon network there are isolated O2− which are tetrahedrally coordinated by Sr and Ln. The crystallographic differentiation of Si/Al and O/N seemed to be possible by a careful evaluation of the single-crystal X-ray diffraction data combined with lattice energy calculations using the MAPLE concept (Madelung Part of Lattice Energy). In the case of Sr3Pr10Si18Al12O18N36 the differentiation of O and N and the proposed ordering was completely confirmed by powder neutron diffraction

Jet Fragmentation via Recombination of Parton Showers

We study hadron production in jets by applying quark recombination to jet shower partons. With the jet showers obtained from PYTHIA and augmented by additional non-perturbative effects, we compute hadron spectra in e+ + e-collisions at sqrt(s)=200 GeV. Including contributions from resonance decays, we find that the resulting transverse momentum spectra for pions, kaons, and protons reproduce reasonably those from the string fragmentation as implemented in PYTHIA.Comment: 4 pages, 3 figures, contribution to Nucleus-Nucleus Collisions 201

Microsporidial Infections in Immunodeficient and Immunocompetent Patients

Microsporidia are obligate, intracellular, spore-forming protozoal parasites. Their host range is extensive and includes most invertebrates and all classes of vertebrates. Five microsporidial genera (Enterocytozoon, Encephalitozoon, Septata, Pleistophom, and Nosema) and unclassified microsporidia have been associated with human disease, which appears to manifest primarily in immunocompromised persons. The clinical manifestations of microsporidiosis are diverse and include intestinal, pulmonary, ocular, muscular, and renal disease. The majority of microsporidial infections in persons infected with human immunodeficiency virus (HIV) are attributed to Enterocytozoon bieneusi, an important cause of chronic diarrhea and wasting. Four cases of microsporidial infection among persons not infected with HIV who had documented or presumed cellular immunodeficiency and four cases of corneal stroma infection due to microsporidia in immunocompetent patients have been described. Furthermore, the first case of traveler's diarrhea due to E. bieneusi in an immunocompetent and otherwise healthy patient is reported in this issue. The sources of human microsporidial infections and modes of transmission are unknow

Intelligent infrastructures systems for sustainable urban environment

Extensive research is now under way around the world to develop advanced technologies to enhance the performances of infrastructure systems. While these technological advances are incremental in nature, they will eventually lead to structures which are distinctly different from the actual infrastructure systems. These new structures will be therefore capable of Structural Health Monitoring (SHM), involving applications of electronics and smart materials, aiming to assist engineers in realizing the full benefits of structural health monitoring.intelligent infrastructures, environment, optimization

HD 41641: A classical δ\delta Sct-type pulsator with chemical signatures of an Ap star

Among the known groups of pulsating stars, $\delta$ Sct stars are one of the least understood. Theoretical models do not predict the oscillation frequencies that observations reveal. Complete asteroseismic studies are necessary to improve these models and better understand the internal structure of these targets. We study the $\delta$ Sct star HD 41641 with the ultimate goal of understanding its oscillation pattern. The target was simultaneously observed by the CoRoT space telescope and the HARPS high-resolution spectrograph. The photometric data set was analyzed with the software package PERIOD04, while FAMIAS was used to analyze the line profile variations. The method of spectrum synthesis was used for spectroscopically determining the fundamental atmospheric parameters and individual chemical abundances. A total of 90 different frequencies was identified and analyzed. An unambiguous identification of the azimuthal order of the surface geometry could only be provided for the dominant p-mode, which was found to be a nonradial prograde mode with m = +1. Using $T_\mathrm{eff}$ and $\log g$, we estimated the mass, radius, and evolutionary stage of HD 41641. We find HD 41641 to be a moderately rotating, slightly evolved $\delta$ Sct star with subsolar overall atmospheric metal content and unexpected chemical peculiarities. HD 41641 is a pure $\delta$ Sct pulsator with p-mode frequencies in the range from 10 d$^{-1}$ to 20 d$^{-1}$. This pulsating star presents chemical signatures of an Ap star and rotational modulation due to surface inhomogeneities, which we consider indirect evidence of the presence of a magnetic field.Comment: 11 pages, 11 figures, accepted for publication in A&

Neural BRDF Representation and Importance Sampling

Controlled capture of real-world material appearance yields tabulated sets of highly realistic reflectance data. In practice, however, its high memory footprint requires compressing into a representation that can be used efficiently in rendering while remaining faithful to the original. Previous works in appearance encoding often prioritized one of these requirements at the expense of the other, by either applying high-fidelity array compression strategies not suited for efficient queries during rendering, or by fitting a compact analytic model that lacks expressiveness. We present a compact neural network-based representation of BRDF data that combines high-accuracy reconstruction with efficient practical rendering via built-in interpolation of reflectance. We encode BRDFs as lightweight networks, and propose a training scheme with adaptive angular sampling, critical for the accurate reconstruction of specular highlights. Additionally, we propose a novel approach to make our representation amenable to importance sampling: rather than inverting the trained networks, we learn to encode them in a more compact embedding that can be mapped to parameters of an analytic BRDF for which importance sampling is known. We evaluate encoding results on isotropic and anisotropic BRDFs from multiple real-world datasets, and importance sampling performance for isotropic BRDFs mapped to two different analytic models