25 research outputs found
Molecular gas in nearby powerful radio galaxies
We report the detection of CO(1-0) and CO(2-1) emission from the central
region of nearby 3CR radio galaxies (z 0.03). Out of 21 galaxies, 8 have
been detected in, at least, one of the two CO transitions. The total molecular
gas content is below 10 \msun. Their individual CO emission exhibit, for 5
cases, a double-horned line profile that is characteristic of an inclined
rotating disk with a central depression at the rising part of its rotation
curve. The inferred disk or ring distributions of the molecular gas is
consistent with the observed presence of dust disks or rings detected optically
in the cores of the galaxies. We reason that if their gas originates from the
mergers of two gas-rich disk galaxies, as has been invoked to explain the
molecular gas in other radio galaxies, then these galaxies must have merged a
long time ago (few Gyr or more) but their remnant elliptical galaxies only
recently (last 10 years or less) become active radio galaxies. Instead, we
argue the the cannibalism of gas-rich galaxies provide a simpler explanation
for the origin of molecular gas in the elliptical hosts of radio galaxies (Lim
et al. 2000). Given the transient nature of their observed disturbances, these
galaxies probably become active in radio soon after the accretion event when
sufficient molecular gas agglomerates in their nuclei.Comment: 6 pages, including 2 figures,in "QSO Hosts and Their Environments",
ed. I. Marquez, in pres
TRY plant trait database - enhanced coverage and open access
Plant traits-the morphological, anatomical, physiological, biochemical and phenological characteristics of plants-determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to biodiversity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of trait-based plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traits-almost complete coverage for 'plant growth form'. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and trait-environmental relationships. These traits have to be measured on individual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects. We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives
Oxidative stress triggers the preferential assembly of base excision repair complexes on open chromatin regions
How DNA repair machineries detect and access, within the context of chromatin, lesions inducing little or no distortion of the DNA structure is a poorly understood process. Removal of oxidized bases is initiated by a DNA glycosylase that recognises and excises the damaged base, initiating the base excision repair (BER) pathway. We show that upon induction of 8-oxoguanine, a mutagenic product of guanine oxidation, the mammalian 8-oxoguanine DNA glycosylase OGG1 is recruited together with other proteins involved in BER to euchromatin regions rich in RNA and RNA polymerase II and completely excluded from heterochromatin. The underlying mechanism does not require direct interaction of the protein with the oxidized base, however, the release of the protein from the chromatin fraction requires completion of repair. Inducing chromatin compaction by sucrose results in a complete but reversible inhibition of the in vivo repair of 8-oxoguanine. We conclude that after induction of oxidative DNA damage, the DNA glycosylase is actively recruited to regions of open chromatin allowing the access of the BER machinery to the lesions, suggesting preferential repair of active chromosome regions
TRY plant trait database - enhanced coverage and open access
Plant traits—the morphological, anatomical, physiological, biochemical and phenological characteristics of plants—determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to biodiversity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of trait‐based plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traits—almost complete coverage for ‘plant growth form’. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and trait–environmental relationships. These traits have to be measured on individual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects. We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives