483 research outputs found

    Using Expert Knowledge to Develop Management Actions for Tasmanian Lowland Native Grasslands under Climate Change

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    Climate change projections for Tasmania suggest that the climate in 2070 will be warmer than present, with increasingly variable seasonal rainfall (Grose et al. 2010). Results from climate change modelling suggest that grassland communities may not exist over their current range in the future (Prober et al. 2012). Lowland temperate natural grasslands have been greatly reduced in areal extent since European settlement in the early 1800s. Two ā€˜Lowland temperate native grasslandā€™ communities are listed as critically endangered under the Environment Protection and Biodiversity Conservation Act (1999): Themeda triandra grasslands and Poa labillardieri grasslands. Careful landscape planning for current and potential future grassland habitat is desirable to reduce negative impacts of climate change on natural grasslands. Experts were gathered at a two-day workshop to discuss potential management options for Tasmanian ecosystems at a range of spatial and temporal scales. This paper reports on the discussion of adaptation actions to allow for the long-term survival of natural grasslands species

    Using machine learning to reduce ensembles of geological models for oil and gas exploration

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    Creating restoration landscapes: partnerships in large-scale conservation in the UK

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    It is increasingly recognized that ecological restoration demands conservation action beyond the borders of existing protected areas. This requires the coordination of land uses and management over a larger area, usually with a range of partners, which presents novel institutional challenges for conservation planners. Interviews were undertaken with managers of a purposive sample of large-scale conservation areas in the UK. Interviews were open-ended and analyzed using standard qualitative methods. Results show a wide variety of organizations are involved in large-scale conservation projects, and that partnerships take time to create and demand resilience in the face of different organizational practices, staff turnover, and short-term funding. Successful partnerships with local communities depend on the establishment of trust and the availability of external funds to support conservation land uses. We conclude that there is no single institutional model for large-scale conservation: success depends on finding institutional strategies that secure long-term conservation outcomes, and ensure that conservation gains are not reversed when funding runs out, private owners change priorities, or land changes hands

    The simplest aminoā€borane H2B=NH2 trapped on a rhodium dimer : preā€catalysts for amineā€“borane dehydropolymerization

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    Funding: The EPSRC (A.S.W. and S.A.M., EP/M024210/1; N.A.B., DTP Studentship), the Rhodes Trust (A.K.), G. M. Adams (G. P. C. analysis).The Ī¼ā€aminoā€“borane complexes [Rh2(LR)2(Ī¼ā€H)(Ī¼ā€H2B=NHRā€²)][BArF4] (LR=R2P(CH2)3PR2; R=Ph, iPr; Rā€²=H, Me) form by addition of H3Bā‹…NMeRā€²H2 to [Rh(LR)(Ī·6ā€C6H5F)][BArF4]. DFT calculations demonstrate that the aminoā€“borane interacts with the Rh centers through strong Rhā€H and Rhā€B interactions. Mechanistic investigations show that these dimers can form by a boroniumā€mediated route, and are preā€catalysts for amineā€borane dehydropolymerization, suggesting a possible role for bimetallic motifs in catalysisPublisher PDFPeer reviewe

    Unexpected Vulnerability of DPEphos to C-O Activation in the Presence of Nucleophilic Metal Hydrides

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    Cāˆ’O bond activation of DPEphos occurs upon mild heating in the presence of [Ru(NHC)2(PPh3)2H2] (NHC=N-heterocyclic carbene) to form phosphinophenolate products. When NHC=IEt2Me2, Cāˆ’O activation is accompanied by Cāˆ’N activation of an NHC ligand to yield a coordinated N-phosphino-functionalised carbene. DFT calculations define a nucleophilic mechanism in which a hydride ligand attacks the aryl carbon of the DPEphos Cāˆ’O bond. This is promoted by the strongly donating NHC ligands which render a trans dihydride intermediate featuring highly nucleophilic hydride ligands accessible. Cāˆ’O bond activation also occurs upon heating cis-[Ru(DPEphos)2H2]. DFT calculations suggest this reaction is promoted by the steric encumbrance associated with two bulky DPEphos ligands. Our observations that facile degradation of the DPEphos ligand via Cāˆ’O bond activation is possible under relatively mild reaction conditions has potential ramifications for the use of this ligand in high-temperature catalysis.</p

    Effects of GABRA2 variation on physiological, psychomotor and subjective responses in the Alcohol Challenge Twin Study

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    Multiple reports have identified variation in the GABRA2 gene as contributing to the genetic susceptibility to alcohol dependence. However, both the mechanism behind this association, and the range of alcohol-related phenotypes affected by variation in this gene, are currently undefined. Other data suggest that the risk of alcohol dependence is increased by relative insensitivity to alcohol's intoxicating effects. We have therefore tested whether GABRA2 variation is associated with variation in the subjective and objective effects of a standard dose of alcohol in humans. Data on responses to alcohol from the Alcohol Challenge Twin Study (Martin et al., 1985) have been tested against allelic and haplotype information obtained by typing 41 single-nucleotide polymorphisms in or close to the GABRA2 gene. Nominally significant allelic associations (p < .05, without correction for multiple testing) were found for body sway, motor coordination, pursuit rotor and arithmetical computation tasks, and for the personality dimension of Neuroticism. Because of the large number of phenotypes tested, these possibly significant findings will need to be confirmed in further studies

    Highly cost-efficient genome-wide association studies using DNA pools and dense SNP arrays

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    Genome-wide association (GWA) studies to map genes for complex traits are powerful yet costly. DNA-pooling strategies have the potential to dramatically reduce the cost of GWA studies. Pooling using Affymetrix arrays has been proposed and used but the efficiency of these arrays has not been quantified. We compared and contrasted Affymetrix Genechip HindIII and Illumina HumanHap300 arrays on the same DNA pools and showed that the HumanHap300 arrays are substantially more efficient. In terms of effective sample size, HumanHap300-based pooling extracts >80% of the information available with individual genotyping (IG). In contrast, Genechip HindIII-based pooling only extracts āˆ¼30% of the available information. With HumanHap300 arrays concordance with IG data is excellent. Guidance is given on best study design and it is shown that even after taking into account pooling error, one stage scans can be performed for >100-fold reduced cost compared with IG. With appropriately designed two stage studies, IG can provide confirmation of pooling results whilst still providing āˆ¼20-fold reduction in total cost compared with IG-based alternatives. The large cost savings with Illumina HumanHap300-based pooling imply that future studies need only be limited by the availability of samples and not cost

    Mitochondrial DNA is critical for longevity and metabolism of transmission stage Trypanosoma brucei.

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    The sleeping sickness parasite Trypanosoma brucei has a complex life cycle, alternating between a mammalian host and the tsetse fly vector. A tightly controlled developmental programme ensures parasite transmission between hosts as well as survival within them and involves strict regulation of mitochondrial activities. In the glucose-rich bloodstream, the replicative 'slender' stage is thought to produce ATP exclusively via glycolysis and uses the mitochondrial F1FO-ATP synthase as an ATP hydrolysis-driven proton pump to generate the mitochondrial membrane potential (Ī”ĪØm). The 'procyclic' stage in the glucose-poor tsetse midgut depends on mitochondrial catabolism of amino acids for energy production, which involves oxidative phosphorylation with ATP production via the F1FO-ATP synthase. Both modes of the F1FO enzyme critically depend on FO subunit a, which is encoded in the parasite's mitochondrial DNA (kinetoplast or kDNA). Comparatively little is known about mitochondrial function and the role of kDNA in non-replicative 'stumpy' bloodstream forms, a developmental stage essential for disease transmission. Here we show that the L262P mutation in the nuclear-encoded F1 subunit Ī³ that permits survival of 'slender' bloodstream forms lacking kDNA ('akinetoplastic' forms), via FO-independent generation of Ī”ĪØm, also permits their differentiation into stumpy forms. However, these akinetoplastic stumpy cells lack a Ī”ĪØm and have a reduced lifespan in vitro and in mice, which significantly alters the within-host dynamics of the parasite. We further show that generation of Ī”ĪØm in stumpy parasites and their ability to use Ī±-ketoglutarate to sustain viability depend on F1-ATPase activity. Surprisingly, however, loss of Ī”ĪØm does not reduce stumpy life span. We conclude that the L262P Ī³ subunit mutation does not enable FO-independent generation of Ī”ĪØm in stumpy cells, most likely as a consequence of mitochondrial ATP production in these cells. In addition, kDNA-encoded genes other than FO subunit a are important for stumpy form viability

    Regional land-use and local management create scale-dependent 'landscapes of fear' for a common woodland bird

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    Context Land-use change and habitat fragmentation are well known drivers of biodiversity declines. In forest birds, it has been proposed that landscape change can cause increased predation pressure that leads to population declines or community change. Predation can also have non-lethal effects on prey, such as creating ā€˜landscapes of fearā€™. However, few studies have simultaneously investigated the relative contribution of regional land-use and local management to creating ā€˜landscapes of fearā€™. Objectives To quantify the relative contribution of regional land-use and local management to the ā€˜landscape of fearā€™ in agricultural landscapes. Methods Bioacoustic recorders were used to quantify Eurasian Wren Troglodytes troglodytes alarm call rates in 32 naturally replicated broadleaf woodlands located in heterogeneous agricultural landscapes. Results Alarm call rates (the probability of an alarm per 10 min of audio) were positively correlated with the amount of agricultural land (arable or pasture) within 500 m of a woodland (effect size of 1) and were higher when livestock were present inside a woodland (effect size of 0.78). The amount of woodland and urban land cover in the landscape also had positive but weak effects on alarm call rates. Woodlands with gamebird management had fewer alarm calls (effect size of āˆ’ā€‰0.79). Conclusions We found that measures of both regional land-use and local management contributed to the ā€˜landscape of fearā€™ in agricultural landscapes. To reduce the impact of anthropogenic activities on ā€˜fearā€™ levels (an otherwise natural ecological process), land-managers should consider limiting livestock presence in woodlands and creating traditional ā€˜buffer stripsā€™ (small areas of non-farmed land) at the interface between woodland edges and agricultural fields
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