Relationships of the Megamerinidae (Diptera: Nerioidea).

Den rezenten Megamerinidae werden lediglich die Gattungen Megamerina Rondani und Texara Walker zugeordnet. Nach einem weitergefaßten Konzept (sensu Hendel) ist die Familie durch 7 Apomorphien charakterisiert. Es wird jedoch gezeigt, daß diese von geringer phylogenetischer Bedeutung sind, da sie sich fast allesamt und in derselben Kombination konvergent in 10 verschiedenen Taxa der Schizophora herausbildeten, die von Hendel nicht den Megamerinidae zugeordnet wurden. Obwohl die Megamerinidae oft zu den Diopsoidea (subjektives Synonym: Nothyboidea) gestellt werden, weisen morphologische Merkmale auf eine nähere Verwandtschaft zu den Nerioidea hin. Die Verwandtschaftsbeziehungen fossiler und rezenter Gattungen werden untersucht.The recent Megamerinidae are here restricted to the genera Megamerina Rondani and Texara Walker. A more inclusive concept of the Megamerinidae (sensu Hendel) is characterised by a set of 7 apomorphic character states. This set is shown to have been separately derived almost in its entirety as a convergent cluster in 10 different schizophoran taxa, other than those included by Hendel. The set therefore has little phylogenetic significance. Though the Megamerinidae are often placed in the superfamily Diopsoidea (subjective syn. Nothyboidea), morphological evidence is presented to indicate a closer relationship to the Nerioidea. The relationships of the fossil and Recent genera are considered

On faint companions in the close environment of star-forming dwarf galaxies. Possible external star formation triggers ?

We have searched for companion galaxies in the close environment of 98 star-forming dwarf galaxies (SFDGs) from field and low density environments, using the NASA Extragalactic Database. Most of the companions are dwarf galaxies which due to observational selection effects were previously disregarded in environmental studies of SFDGs. A subsample at low redshift, cz<2000 km/s, was chosen to partially eliminate the observational bias against distant dwarf companions. We find companion candidates for approximately 30% of the objects within a projected linear separation s_p<100 kpc and a redshift difference (Delta cz)<500 km/s. The limited completeness of the available data sets, together with the non-negligible frequency of HI clouds in the vicinity of SFDGs indicated by recent radio surveys, suggest that a considerably larger fraction of these galaxies may be accompanied by low-mass systems. This casts doubt on the hypothesis that the majority of them can be considered truly isolated. The velocity differences between companion candidates and sample SFDGs amount typically to (Delta cz)<250 km/s, and show a rising distribution towards lower (Delta cz). This is similarly found for dwarf satellites of spiral galaxies, suggesting a physical association between the companion candidates and the sample SFDGs. SFDGs with a close companion do not show significant differences in their Hbeta equivalent widths and B-V colours as compared to isolated ones. However, the available data do not allow us to rule out that interactions with close dwarf companions can influence the star formation activity in SFDGs.Comment: 9 pages, 5 figures, to appear in A&A; also available at http://www.uni-sw.gwdg.de/~knoeske/PUB_LIST/sfdg_comps.ps.g

The Stripe 82 1-2 GHz Very Large Array Snapshot Survey: Multiwavelength Counterparts

We have combined spectrosopic and photometric data from the Sloan Digital Sky Survey (SDSS) with $1.4$ GHz radio observations, conducted as part of the Stripe 82 $1-2$ GHz Snapshot Survey using the Karl G. Jansky Very Large Array (VLA), which covers $\sim100$ sq degrees, to a flux limit of 88 $\mu$Jy rms. Cross-matching the $11\,768$ radio source components with optical data via visual inspection results in a final sample of $4\,795$ cross-matched objects, of which $1\,996$ have spectroscopic redshifts and $2\,799$ objects have photometric redshifts. Three previously undiscovered Giant Radio Galaxies (GRGs) were found during the cross-matching process, which would have been missed using automated techniques. For the objects with spectroscopy we separate radio-loud Active Galactic Nuclei (AGN) and star-forming galaxies (SFGs) using three diagnostics and then further divide our radio-loud AGN into the HERG and LERG populations. A control matched sample of HERGs and LERGs, matched on stellar mass, redshift and radio luminosity, reveals that the host galaxies of LERGs are redder and more concentrated than HERGs. By combining with near-infrared data, we demonstrate that LERGs also follow a tight $K-z$ relationship. These results imply the LERG population are hosted by population of massive, passively evolving early-type galaxies. We go on to show that HERGs, LERGs, QSOs and star-forming galaxies in our sample all reside in different regions of a WISE colour-colour diagram. This cross-matched sample bridges the gap between previous `wide but shallow' and `deep but narrow' samples and will be useful for a number of future investigations.Comment: 17 pages, 19 figures. Resubmitted to MNRAS after the initial comment

Evolution in the bias of faint radio sources to z ~ 2.2

Quantifying how the baryonic matter traces the underlying dark matter distribution is key to both understanding galaxy formation and our ability to constrain the cosmological model. Using the cross-correlation function of radio and near-infrared galaxies, we present a large-scale clustering analysis of radio galaxies to z ~ 2.2. We measure the angular auto-correlation function of Ks90μJy to infer linear bias of radio galaxies in four redshift bins. We find that the bias evolves from b = 0.57 ± 0.06 at z ~ 0.3 to 8.55 ± 3.11 at z ~ 2.2. Furthermore, we separate the radio sources into subsamples to determine how the bias is dependent on the radio luminosity, and find a bias which is significantly higher than predicted by the simulations of Wilman et al., and consistent with the lower luminosity but more abundant FR-I population having a similar bias to the highly luminous but rare FR-IIs. Our results are suggestive of a higher mass, particularly for FR-I sources than assumed in simulations, especially towards higher redshift.Peer reviewe

Reframing landscape fragmentation's effects on ecosystem services.

REVIEWLandscape structure and fragmentation have important effects on ecosystem services, with a common assumption being that fragmentation reduces service provision. This is based on fragmentation's expected effects on ecosystem service supply, but ignores how fragmentation influences the flow of services to people. Here we develop a new conceptual framework that explicitly considers the links between landscape fragmentation, the supply of services, and the flow of services to people. We argue that fragmentation's effects on ecosystem service flow can be positive or negative, and use our framework to construct testable hypotheses about the effects of fragmentation on final ecosystem service provision. Empirical efforts to apply and test this framework are critical to improving landscape management for multiple ecosystem services.Australian Research Council Discovery ProjectAustralian Research Council's Centre of Excellence for Environmental DecisionsNERCChile Ministry of EducationCSIRO Integrative Natural Resource Management postgraduate fellowshipsCOLCIENCIA

Evolution of faint radio sources in the VIDEO-XMM3 field

© 2013 The Authors Published by Oxford University Press on behalf of the Royal Astronomical SocietyIt has been speculated that low-luminosity radio-loud active galactic nuclei (AGN) have the potential to serve as an important source of AGN feedback, and may be responsible for suppressing star formation activity in massive elliptical galaxies at late times. As such the cosmic evolution of these sources is vitally important to understand the significance of such AGN feedback processes and their influence on the global star formation history of the Universe. In this paper, we present a new investigation of the evolution of faint radio sources out to z ~ 2.5. We combine a 1 square degree Very Large Array radio survey, complete to a depth of 100 μJy, with accurate 10 band photometric redshifts from the following surveys: Visible and Infrared Survey Telescope for Astronomy Deep Extragalactic Observations and Canada-France-Hawaii Telescope Legacy Survey. The results indicate that the radio population experiences mild positive evolution out to z ~ 1.2 increasing their space density by a factor of ~3, consistent with results of several previous studies. Beyond z = 1.2, there is evidence of a slowing down of this evolution. Star-forming galaxies drive the more rapid evolution at low redshifts, z 1.2. The evolution is best fitted by pure luminosity evolution with star-forming galaxies evolving as (1 + z)2.47 ± 0.12 and AGN as (1 + z)1.18 ± 0.21M.Peer reviewe

Rare A-Type, Spiro-Type, and Highly Oligomeric Proanthocyanidins from \u3cem\u3ePinus massoniana\u3c/em\u3e

An investigation of the dental bioactive proanthocyanidin (PAC) oligomer fractions led to three structurally distinct new PACs (1–3) from pine bark. Pinutwindoublin (1) is the first reported trimer with double A-type interflavanyl linkages (2α→O→5,4α→6 and 2α→O→7,4α→8). Pinuspirotetrin (2) represents the first reported PAC tetramer with a heterodimeric framework consisting of one spiro-type and one A-type dimer. Pinumassohexin (3) was elucidated as a mixed A + B-type hexamer that consists of a peanut-derived tetramer, peanut procyanidin E, and an A-type dimer (5). Compound 3 increased the modulus of elasticity of dentin by an impressive 4.3 times at a concentration of 0.65%

The relation between galaxy density and radio jet power for 1.4 GHz VLA selected AGNs in Stripe 82

Using a Karl G. Jansky Very Large Array (VLA) L-band (1-2 GHz) survey covering ∼100 deg2 of the Stripe 82 field, we have obtained a catalogue of 2716 radio AGNs. For these AGNs, we investigate the impact of galaxy density on 1.4 GHz radio luminosity (L1.4). We determine their close environment densities using the surface density parameter, ΣN, for N = 2 and N = 5, which we bin by redshift to obtain a pseudo-3D galaxy density measure. Matching the radio AGNs to sources without radio detections in terms of redshift, K-band magnitude and (g − K) colour index, we obtain samples of control galaxies and determine whether radio AGN environments differ from this general population