866 research outputs found
A conversation with Isca Wittenberg
This paper, based on a conversation with Isca Wittenberg, summarises the dialogue between her and the author and highlights the main points of their discussion, including the observational method, the role of the observer and the influence on clinical practice
Draft Genome Sequences of 15 Staphylococcus aureus Isolates Recovered from Raw Milk and Associated Milk Filters from Victoria, Australia
This study describes draft whole genomes of 15 Staphylococcus aureus isolates from dairy farms located in Victoria, Australia. Two novel sequence types (ST3183 and ST3184) were identified among these isolates
Modelling biodiversity scenarios in madagascar under both the effects of climate change and anthropogenic deforestation
Madagascar is widely known for its exceptional biodiversity which is, for the terrestrial part, mainly concentrated in tropical forests. This biodiversity is severely threatened by both climate change and deforestation. The FRB (Fondation pour la Recherche sur la Biodiversité) project named BioSceneMada (http://bioscenemada.net) aims at modelling the biodiversity scenarios in Madagascar under both the effects of climate change and anthropogenic deforestation. In this study we present the first results of the project. We used presence data for more than 5000 species and bioclimatic envelope models to forecast species distribution under the effects of climate change. Species distribution maps were used to identify potential refugia for biodiversity. Combining these results to the projections of a deforestation model, we also identified the potential biodiversity hotspots under a high risk of deforestation. Project results should help define efficient strategies for conserving Madagascan biodiversity. In particular, we promote the inclusion of top priority areas for biodiversity conservation into the current Madagascar protected areas system
Enhanced heterogeneity of rpoB in Mycobacterium tuberculosis found at low pH.
OBJECTIVES: The aim of this study was to gain an insight into the molecular mechanisms of the evolution of rifampicin resistance in response to controlled changes in the environment. METHODS: We determined the proportion of rpoB mutants in the chemostat culture and characterized the sequence of mutations found in the rifampicin resistance-determining region of rpoB in a steady-state chemostat at pH 7.0 and 6.2. RESULTS: The overall proportion of rpoB mutants of strain H37Rv remained constant for 37 days at pH 7.0, ranging between 3.6 x 10(-8) and 8.9 x 10(-8); however, the spectrum of mutations varied. The most commonly detected mutation, serine to leucine mutation at codon 531 (S531L), increased from 40% to 89%, while other mutations (S531W, H526Y, H526D, H526R, S522L and D516V) decreased over the 37 day sampling period. Changing the pH from 7.0 to 6.2 did not significantly alter the overall proportion of mutants, but resulted in a decrease in the percentage of strains harbouring S531L (from 89% to 50%) accompanied by an increase in the range of different mutations from 4 to 12. CONCLUSIONS: The data confirm that the fitness of strains with the S531L mutation is greater than that of strains containing other mutations. We also conclude that at low pH the environment is permissive for a wider spectrum of mutations, which may provide opportunities for a successful mutant to survive
Draft Genome Sequences of 15 Isolates of Listeria monocytogenes Serotype 1/2a, Subgroup ST204
Listeria monocytogenes sequence type 204 (ST204) strains have been isolated from a range of food, environmental, and clinical sources in Australia. This study describes the draft genome sequences of 15 isolates collected from meat and dairy associated sources
Combining global tree cover loss data with historical national forest cover maps to look at six decades of deforestation and forest fragmentation in Madagascar
The island of Madagascar has a unique biodiversity, mainly located in the tropical forests of the island. This biodiversity is highly threatened by anthropogenic deforestation. Existing historical forest maps at national level are scattered and have substantial gaps which prevent an exhaustive assessment of long-term deforestation trends in Madagascar. In this study, we combined historical national forest cover maps (covering the period 1953–2000) with a recent global annual tree cover loss dataset (2001–2014) to look at six decades of deforestation and forest fragmentation in Madagascar (from 1953 to 2014). We produced new forest cover maps at 30 m resolution for the year 1990 and annually from 2000 to 2014 over the full territory of Madagascar. We estimated that Madagascar has lost 44% of its natural forest cover over the period 1953–2014 (including 37% over the period 1973–2014). Natural forests cover 8.9 Mha in 2014 (15% of the national territory) and include 4.4 Mha (50%) of moist forests, 2.6 Mha (29%) of dry forests, 1.7 Mha of spiny forests (19%) and 177 000 ha (2%) of mangroves. Since 2005, the annual deforestation rate has progressively increased in Madagascar to reach 99 000 ha/yr during 2010–2014 (corresponding to a rate of 1.1%/yr). Around half of the forest (46%) is now located at less than 100 m from the forest edge. Our approach could be replicated to other developing countries with tropical forest. Accurate forest cover change maps can be used to assess the effectiveness of past and current conservation programs and implement new strategies for the future. In particular, forest maps and estimates can be used in the REDD+ framework which aims at “Reducing Emissions from Deforestation and forest Degradation” and for optimizing the current protected area network
Solution generating with perfect fluids
We apply a technique, due to Stephani, for generating solutions of the
Einstein-perfect fluid equations. This technique is similar to the vacuum
solution generating techniques of Ehlers, Harrison, Geroch and others. We start
with a ``seed'' solution of the Einstein-perfect fluid equations with a Killing
vector. The seed solution must either have (i) a spacelike Killing vector and
equation of state P=rho or (ii) a timelike Killing vector and equation of state
rho+3P=0. The new solution generated by this technique then has the same
Killing vector and the same equation of state. We choose several simple seed
solutions with these equations of state and where the Killing vector has no
twist. The new solutions are twisting versions of the seed solutions
Population genetic structure of serotine bats (Eptesicus serotinus) across Europe and implications for the potential spread of bat rabies (European bat lyssavirus EBLV-1)
This is the author accepted manuscript. The final version is available from the publisher via the DOI in this record.Understanding of the movements of species at multiple scales is essential to appreciate patterns of population connectivity and in some cases, the potential for pathogen transmission. The serotine bat (Eptesicus serotinus) is a common and widely distributed species in Europe where it frequently harbours European bat lyssavirus type 1 (EBLV-1), a virus causing rabies and transmissible to humans. In the United Kingdom, it is rare, with a distribution restricted to south of the country and so far the virus has never been found there. We investigated the genetic structure and gene flow of E. serotinus across the England and continental Europe. Greater genetic structuring was found in England compared with continental Europe. Nuclear data suggest a single population on the continent, although further work with more intensive sampling is required to confirm this, while mitochondrial sequences indicate an east-west substructure. In contrast, three distinct populations were found in England using microsatellite markers, and mitochondrial diversity was very low. Evidence of nuclear admixture indicated strong male-mediated gene flow among populations. Differences in connectivity could contribute to the high viral prevalence on the continent in contrast with the United Kingdom. Although the English Channel was previously thought to restrict gene flow, our data indicate relatively frequent movement from the continent to England highlighting the potential for movement of EBLV-1 into the United Kingdom.We acknowledge DEFRA and University of Exeter for funding this stud
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