The environment of AGNs and the activity degree of their surrounding galaxies

Aims. We present results of a comprehensive spectral study on the large-scale environment of AGNs based on Sloan Spectroscopic Survey data. Methods. We analyzed the spectra of galaxies in the environment of AGN and other activity classes up to distances of 1 Mpc. Results. The mean H{\alpha} and [OIII] {\lambda}5007 line luminosities in the environmental galaxies within a projected radius of 1 Mpc are highest around Seyfert 1 galaxies, with decreasing luminosities for Seyfert 2 and HII galaxies, and lowest for absorption line galaxies. Furthermore, there is a trend toward H{\alpha} and [OIII] luminosities in the environmental galaxies increasing as a function of proximity to the central emission line galaxies. There is another clear trend toward a neighborhood effect within a radius of 1000 kpc for the AGN and non-AGN types: Seyfert galaxies tend to have the highest probability of having another Seyfert galaxy in the neighborhood. HII galaxies tend to have the highest probability of having another HII galaxy in the neighborhood, etc. The number of companions within 1000 kpc is inversely correlated with the H{\alpha}, [OIII] {\lambda}5007, as well as with the continuum luminosities of the central galaxies, regardless of whether they are of Seyfert, HII, or absorption line types.Comment: 9 pages, 6 figures, to be published in A&

Investigating the sources of process innovation among UK manufacturing firms

Accepted versio

Relations and evolution in "Cheilanthes" ("Sinopteridaceae, Pteridophyta") in Macaronesia and Mediterranean area, deduced from genome analysis of their hybrids

Nine species of "Cheilantoid ferns" are known to grow in Macaronesia and the Mediterranean basin. Two of them (lacking a pseudo-indusium and having the basic chromosome number X = 29), both aggregate species which we prefer to retain in Notholaena, are not included in this study. The other seven species (with distinct pseudo-indusium and the basic chromosome number X = 30), which we accept as members of the genus Cheilanthes Sw. sensu stricto, were subjected to detailed genome analysis of their natural and experimentally produced hybrids and shown to represent an aggregate of four very distinct ancestral diploids and three allotetraploids. The latter must have once been formed by chromosome doubling in the three diploid hybrids of C. maderensis Lowe with the other three diploid species. Theoretically three more allotetraploids would be possible but their formation has obviously been prevented by the geographical separation of the three respective diploids. The most widely distributed of the tetraploids, i.e. C. pteridioides (Reich.) C.Chr. has also been resynthesized from its ancestors (still sympatric) under experimental conditions. The intermediate morphology of the allotetraploids (as compared with their diploid ancestors) is obviously the reason why their status and existence has so long escaped recognition in Europe. These seven species form a natural group and, in our opinion, should not be divided into sections.Se conocen nueve especies de "helechos Cheilantoides" que viven en Macaronesia y la cuenca Mediterranea. Dos de ellos, (sin pseudoindusio y con número cromosómico básico X = 29) que preferimos incluir en Notholaena, no se estudian en este trabajo. Las otras siete especies (con pseudoindusio y número cromosómico básico X = 30) que reconocemos como miembros del género Cheilanthes Sw. sensu stricto, fueron objeto de un análisis detallado del genoma de sus híbridos, tanto de los naturales, como de los producidos experimentalmente mostrando un agregado de cuatro ancestrales diploides muy distintos y tres alotetraploides. Estos últimos deben haberse formado por duplicación de los cromosomas en los tres híbridos diploides resultantes del cruzamiento de C. maderensis con las otras tres especies diploides. Teóricamente son posibles otros tres alotetraploides, pero su formación se ha impedido por la separación geográfica de los 3 diploides respectivos. Los tetraploides más ampliamente distribuidos, como por ejemplo Cheilanthes pteridioides (Reich.) C. Chr., han sido igualmente resintetizados a partir de sus ancestros bajo condiciones experimentales. La morfología intermedia de los alotetraploides (comparada con sus ancestros diploides) es obviamente la razón por la que su existencia y status han pasado inadvertidos en Europa. Estas siete especies forman un grupo natural que, en nuestra opinión, no debe ser dividido en secciones

Are spine-sheath polarization structures in the jets of active galactic nuclei associated with helical magnetic fields?

One possible origin for polarization structures across jets of active galactic nuclei (AGNs) with a central 'spine' of orthogonal magnetic field and a 'sheath' of longitudinal magnetic field along one or both edges of the jet is the presence of a helical jet magnetic field. Simultaneous Very Long Baseline Array (VLBA) polarization observations of AGN displaying partial or full spine-sheath polarization structures were obtained at 4.6, 5.0, 7.9, 8.9, 12.9 and 15.4 GHz, in order to search for additional evidence for helical jet magnetic fields, such as transverse Faraday rotation gradients (due to the systematic change in the line-of-sight magnetic-field component across the jet). Results for eight sources displaying monotonic transverse Faraday rotation gradients with significances >= 3 sigma are presented here. Reversals in the directions of the transverse RM gradients with distance from the core or with time are detected in three of these AGNs. These can be interpreted as evidence for a nested helical magnetic field structure, with different directions for the azimuthal field component in the inner and outer regions of helical field. The results presented here support the idea that many spine-sheath polarization structures reflect the presence of helical magnetic fields being carried by these jets

Australian national residue survey – closing the loop on pesticide residue risk management for Australian grain

Australia exports a major proportion of its agricultural production and is highly dependent on maintaining and developing access to, and competitiveness in, export markets. To preserve Australia’s status as a provider of high quality grain, the majority of Australian primary producers rely on pesticides to protect their crops from pests and diseases, particularly in post-harvest situations. The Australian Pesticides and Veterinary Medicines Authority (APVMA) supports Australian agriculture by registering and allowing the supply of safe and effective animal health and crop protection products. A residue risk management continuum is established when the effectiveness of chemical registration and control of chemical use regulations is assessed through residue monitoring programs. Programs assess good agricultural practice and provide traceback capacity to investigate areas of concern. Risk communication provides opportunities for continuous improvement. In the early 1960s, the Australian Government established a non-regulatory body, the national residue survey (NRS). In 2008-2009, random monitoring programs were conducted for over 50 commodities (21 grains, five horticultural commodities, 11 fish species, 12 animal species, honey and egg with over 20,000 samples collected for analytical testing. The NRS grain residue monitoring program is presented as a case study of the residue risk management continuum demonstrating to overseas markets the high level of residue integrity of Australian grain. Over 4,000 grain samples are collected and analysed per annum. Most of the samples are collected in the bulk export program where samples are collected from every hatch of every ship loaded at the seventeen Australian grain export terminals. The chemical screens have expanded beyond the multi-residue screen (MRS) insecticides, fungicides and herbicides, to include phosphine, additional herbicides (not included in the MRS), heavy metals and mycotoxins. In its current form, the NRS grains program provides 15 years of residue testing data which demonstrates a very high degree of conformance with Australian MRLs and the import tolerances of overseas trading partners. In addition, trends in residue testing data demonstrate a decline in the frequency of residue detections and the levels of residue detected. To be confident that residue testing results meet the requisite standards, the reliability of the Australian analyses must be assured. The NRS laboratory performance evaluation system has been developed to provide that assurance, using a range of proficiency tests and other techniques in the selection of laboratories for NRS work. Residue testing results are reported against both Australian MRLs and the international MRLs which apply in the relevant export market. NRS maintains databases of overseas MRLs and compares its residue testing results of exported commodities against those standards. Grain marketers receive certificates of analysis, in the form of NRS residue testing results, for each shipment prior to arrival at the overseas market.Keywords: Grain, Pesticide, residue, monitoring program, residue risk managemen

Estimation of axial compressor body forces using three-dimensional flow computations

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2009.Includes bibliographical references (p. 77-78).This thesis presents an examination of body force distributions in a single stage low speed compressor. The body force distributions are developed using two different computational procedures, an axisymmetric streamline curvature calculation and an unsteady, three-dimensional flow simulation. A two-dimensional body force representation is defined as a benchmark to evaluate the departures of the computed forces from two-dimensional behavior. The most important contribution to this departure (for both the streamline curvature calculation and the three-dimensional simulation) is identified as the change in streamtube height across the blade rows. The magnitude of the departures increase with blade loading and, for the compressor examined, are smaller than five per cent of the two-dimensional estimate at design but show values up to 50 per cent near stall.by Georg A. Reichstein.S.M

Apolarity, Hessian and Macaulay polynomials

A result by Macaulay states that an Artinian graded Gorenstein ring R of socle dimension one and socle degree b can be realized as the apolar ring of a homogeneous polynomial f of degree b. If R is the Jacobian ring of a smooth hypersurface g=0, then b is just equal to the degree of the Hessian polynomial of g. In this paper we investigate the relationship between f and the Hessian polynomial of g.Comment: 12 pages. Improved exposition, minor correction