25 research outputs found
Radio-Continuum study of the Nearby Sculptor Group Galaxies. Part 1: NGC 300 at lambda = 20 cm
A series of new radio-continuum (lambda=20 cm) mosaic images focused on the
NGC 300 galactic system were produced using archived observational data from
the VLA and/or ATCA. These new images are both very sensitive (rms=60 microJy)
and feature high angular resolution (<10"). The most prominent new feature is
the galaxy's extended radio-continuum emission, which does not match its
optical appearance. Using these newly created images a number of previously
unidentified discrete sources have been discovered. Furthermore, we demonstrate
that a joint deconvolution approach to imaging this complete data-set is
inferior when compared to an immerge approach.Comment: 13 pages, 12 figures, accepted to APSS, new version to correct the
missing reference
Impacts of salvage logging on biodiversity: A meta-analysis
Logging to "salvage" economic returns from forests affected by natural disturbances has become increasingly prevalent globally. Despite potential negative effects on biodiversity, salvage logging is often conducted, even in areas otherwise excluded from logging and reserved for nature conservation, inter alia because strategic priorities for post-disturbance management are widely lacking. A review of the existing literature revealed that most studies investigating the effects of salvage logging on biodiversity have been conducted less than 5 years following natural disturbances, and focused on non-saproxylic organisms. A meta-analysis across 24 species groups revealed that salvage logging significantly decreases numbers of species of eight taxonomic groups. Richness of dead wood dependent taxa (i.e. saproxylic organisms) decreased more strongly than richness of non-saproxylic taxa. In contrast, taxonomic groups typically associated with open habitats increased in the number of species after salvage logging. By analysing 134 original species abundance matrices, we demonstrate that salvage logging significantly alters community composition in 7 of 17 species groups, particularly affecting saproxylic assemblages. Synthesis and applications. Our results suggest that salvage logging is not consistent with the management objectives of protected areas. Substantial changes, such as the retention of dead wood in naturally disturbed forests, are needed to support biodiversity. Future research should investigate the amount and spatio-temporal distribution of retained dead wood needed to maintain all components of biodiversity
Estimating retention benchmarks for salvage logging to protect biodiversity
S.T. was supported by the Humboldt-Foundation and by the MOST (Ministry of Science
and Technology) Taiwan Research Fellowship to work with A.C. at National Tsing Hua
University, Taiwan. S.T. received funds from the Gregor Louisoder Environmental
Foundation. A.B.L. received funds from the Humboldt-Foundation.Forests are increasingly affected by natural disturbances. Subsequent salvage logging, a
widespread management practice conducted predominantly to recover economic capital,
produces further disturbance and impacts biodiversity worldwide. Hence, naturally disturbed
forests are among the most threatened habitats in the world, with consequences for their
associated biodiversity. However, there are no evidence-based benchmarks for the proportion
of area of naturally disturbed forests to be excluded from salvage logging to conserve biodiversity.
We apply a mixed rarefaction/extrapolation approach to a global multi-taxa dataset
from disturbed forests, including birds, plants, insects and fungi, to close this gap. We find
that 75 ± 7% (mean ± SD) of a naturally disturbed area of a forest needs to be left unlogged
to maintain 90% richness of its unique species, whereas retaining 50% of a naturally disturbed
forest unlogged maintains 73 ± 12% of its unique species richness. These values do
not change with the time elapsed since disturbance but vary considerably among taxonomic
groups.Open Access funding enabled and organized by Projekt DEA
Adherence to treatment of osteoporosis: a need for study
Adherence to anti-osteoporosis medications is currently low and is associated with poor anti-fracture efficacy. This manuscript reviews the potential design of clinical studies that aim to demonstrate improved adherence, with new chemical entities to be used in the management of osteoporosis. Introduction Several medications have been unequivocally shown to decrease fracture rates in clinical trials. However, in real life settings, long-term persistence and compliance to anti-osteoporosis medication is poor, hence decreasing the clinical benefits for patients. Methods An extensive search of Medline from 1985 to 2006 retrieved all trials including the keywords osteoporosis, compliance, persistence or adherence followed by a critical appraisal of the data obtained through a consensus expert meeting. Results The impact of non-adherence on the clinical development of interventions is reviewed, so that clinicians, regulatory agencies and reimbursement agencies might be better informed of the problem, in order to stimulate the necessary research to document adherence. Conclusion Adherence to therapy is a major problem in the treatment of osteoporosis. Both patients and medication factors are involved. Adherence studies are an important aspect of outcomes studies, but study methodologies are not well developed at the moment and should be improved. Performing adherence studies will be stimulated when registration authorities accept the result of these studies and include the relevant information in Sect. 5.1 of the summary of product characteristics. Reimbursement authorities might also consider such studies as important information for decisions on reimbursement