2,014 research outputs found

    Implications of the prevalence and magnitude of sustained declines for determining a minimum threshold for favourable population size.

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    We propose a new approach to quantifying a minimum threshold value for the size of an animal population, below which that population might be categorised as having unfavourable status. Under European Union law, the concept of Favourable Conservation Status requires assessment of populations as having favourable or unfavourable status, but quantitative methods for such assessments have not yet been developed. One population threshold that is well established in conservation biology is the minimum viable population (MVP) defined as the size of a small but stable population with an acceptably low risk of extinction within a specified period. Our approach combines this small-population paradigm MVP concept with a multiplier, which is a factor by which the MVP is multiplied to allow for the risk of a sustained future decline. We demonstrate this approach using data on UK breeding bird population sizes. We used 43-year time-series data for 189 species and a qualitative assessment of population trends over almost 200 years for 229 species to examine the prevalence, duration and magnitude of sustained population declines. Our study addressed the problem of underestimation of the duration and magnitude of declines caused by short runs of monitoring data by allowing for the truncation of time series. The multiplier was derived from probability distributions of decline magnitudes within a given period, adjusted for truncation. Over a surveillance period of 100 years, we estimated that there was a 10% risk across species that a sustained population decline of at least sixteen-fold would begin. We therefore suggest that, in this case, a factor of 16 could be used as the multiplier of small-population MVPs to obtain minimum threshold population sizes for favourable status. We propose this 'MVP Multiplier' method as a new and robust approach to obtaining minimum threshold population sizes which integrates the concepts of small-population and declining-population paradigms. The minimum threshold value we propose is intended for use alongside a range of other measures to enable overall assessments of favourable conservation status

    Analyzing Vertical Mergers: Accounting for the Unilateral Effects Tradeoff and Thinking Holistically About Efficiencies

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    With the adoption of the 2020 Vertical Merger Guidelines, the U.S. antitrust agencies have updated their guidance on vertical mergers for the Twenty-First Century. Although economists have long recognized the procompetitive benefits most vertical mergers generate, the law has not always followed suit, and has sometimes condemned vertical mergers for making the merged firm more efficient. In this article, we attempt to catalogue the extensive list of efficiencies that vertical mergers can generate, trace the often halting efforts to incorporate these insights into the law, and propose a framework that courts and agencies can use to assess the likely competitive effects of vertical transactions. We draw heavily upon leading cases, particularly Baker Hughes and AT&T, with two refinements. First, consistent with the final Guidelines (but not the earlier draft) and the economic literature noting a symmetry between unilateral anticompetitive effects (raising rivalsā€™ costs) and procompetitive effects (the elimination of double marginalization), which we call the ā€œunilateral effects tradeoff,ā€ we argue a plaintiff alleging a raising rivals cost (RRC) theory of harm must also address EDM as part of its prima facie case. Second, if the plaintiff carries its prima facie burden, then the defendant should be able to argue, and courts and Agencies should seriously consider, the full range of procompetitive efficiencies, which we call a ā€œholistic efficiency analysis.

    Phylogeny of Abildgaardieae (Cyperaceae) Inferred from ITS and trnLā€“F Data

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    Within the tribe Abildgaardieae, the relationships between Fimbristylis and its relatives have not been certain, and the limits of Fimbristylis have been unclear, with Bulbostylis and Abildgaardia variously combined with it and each other. The relationships and limits of tribes Abildgaardieae and Arthrostylideae and their genera were evaluated across 49 representative species using parsimony and maximum likelihood analyses of ITS (nuclear ribosomal) and trnLā€“F (plastid) DNA sequence data separately and combined. The evolutionary reconstructions derived from sequences of cpDNA and nrDNA disagree about the position of tribe Arthrostylideae relative to Abildgaardieae; Arthrostylis and Actinoschoenus are either nested within Abildgaardieae (trnLā€“F data) or very closely related to this tribe (ITS data). The reconstructions also disagree about the monophyly of genus Abildgaardia (excluding A. vaginata). Crosslandia and A. vaginata form a clade that is nested within Fimbristylis. Bulbostylis is monophyletic and clearly separated from Fimbristylis. Further sampling of taxa and characters is needed to resolve and/or strengthen support for some of these ā€˜ā€˜deepā€™ā€™ and ļ¬ne-scale relationships

    Chronology of a Fortified Mississippian Village in the Central Illinois River Valley

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    Geophysical survey and excavations from 2010ā€“2016 at Lawrenz Gun Club (11CS4), a late pre-Columbian village located in the central Illinois River valley in Illinois, identified 10 mounds, a central plaza, and dozens of structures enclosed within a stout 10 hectare bastioned palisade. Nineteen radiocarbon (14C) measurements were taken from single entities of wood charcoal, short-lived plants, and animal bones. A site chronology has been constructed using a Bayesian approach that considers the stratigraphic contexts and feature formation processes. The village was host to hundreds of years of continuous human activity during the Mississippi Period. Mississippian activity at the site is estimated to have begun in cal AD 990ā€“1165 (95% probability), ended in cal AD 1295ā€“1450 (95% probability), and lasted 150ā€“420 yr (95% probability) in the primary Bayesian model with similar results obtained in two alternative models. The palisade is estimated to have been constructed in cal AD 1150ā€“1230 (95% probability) and was continuously repaired and rebuilt for 15ā€“125 yr (95% probability), probably for 40ā€“85 yr (68% probability). Comparison to other studies demonstrates that the bastioned palisade at Lawrenz was one of the earliest constructed in the midcontinental United States

    Gut microbiota modulation of chemotherapy efficacy and toxicity

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    Evidence is growing that the gut microbiota modulates the host response to chemotherapeutic drugs, with three main clinical outcomes: facilitation of drug efficacy; abrogation and compromise of anticancer effects; and mediation of toxicity. The implication is that gut microbiota are critical to the development of personalized cancer treatment strategies and, therefore, a greater insight into prokaryotic co-metabolism of chemotherapeutic drugs is now required. This thinking is based on evidence from human, animal and in vitro studies that gut bacteria are intimately linked to the pharmacological effects of chemotherapies (5-fluorouracil, cyclophosphamide, irinotecan, oxaliplatin, gemcitabine, methotrexate) and novel targeted immunotherapies such as anti-PD-L1 and anti-CLTA-4 therapies. The gut microbiota modulate these agents through key mechanisms, structured as the 'TIMER' mechanistic framework: Translocation, Immunomodulation, Metabolism, Enzymatic degradation, and Reduced diversity and ecological variation. The gut microbiota can now, therefore, be targeted to improve efficacy and reduce the toxicity of current chemotherapy agents. In this Review, we outline the implications of pharmacomicrobiomics in cancer therapeutics and define how the microbiota might be modified in clinical practice to improve efficacy and reduce the toxic burden of these compounds

    Fodder crop management benefits Northern Lapwing (Vanellus vanellus) outside agri-environment schemes

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    To date, agri-environment schemes (AES) have had limited success in reversing biodiversity loss over greater spatial extents than fields and farms, and vary widely in their cost-effectiveness. Here, over nine years, we make use of the management initiative of a farmer in an upland livestock farming landscape in Scotland, undertaken wholly outside AES, to examine its effect on breeding densities of Northern Lapwing Vanellus vanellus. Management designed by the farmer involved planting a Brassica fodder crop for two consecutive years followed by reseeding with grass, with eight out of 17 fields at the farm undergoing this management since 1997. After controlling for other habitat parameters of importance, the density of breeding Lapwings was 52% higher in fields that had undergone fodder crop management than those that had not. Densities were highest in the first year after the fodder crop was planted, prior to reseeding with grass, but remained above levels in control fields for approximately seven years after the fodder crop was last planted. Very high Lapwing densities (modelled densityā€Æ=ā€Æ1 pair ha-1) in the year after the fodder crop was planted likely result from the heterogeneous ground surface created by grazing of the crop providing an ā€œattractiveā€ nesting habitat. Continued high densities following reseeding with grass may partly be accounted for by philopatry, but the fact that they are field-specific also suggests that these fields continue to offer enhanced foraging conditions for several years. Fodder crop management was implemented at the study site to fatten lambs over winter and ultimately improve grass condition for grazing. This system is therefore based on active farming and benefits both the farmer and breeding Lapwings. As such, it may be possible to implement it more widely without the need for high agri-environment payments. More generally, it is an example of the land owner being actively involved in developing conservation solutions in partnership with environmental research, rather than being seen as a passive recipient of knowledge as has typically been the case with the design of AES. Such approaches need to be adopted more consistently in designing interventions for environmental outcomes on farmland, but may be of particular importance in the UK if the certainties of European Union AES are to come to an end

    The impact of selective genotyping on the response to selection using single-step genomic best linear unbiased prediction

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    Across the majority livestock species, routinely collected genomic and pedigree information has been incorporated into evaluations using single-step methods. As a result, strategies that reduce genotyping costs without reducing the response to selection are important as they could have substantial economic impacts on breeding programs. Therefore, the objective of the current study was to investigate the impact of selectively genotyping selection candidates on the selection response using simulation. Populations were simulated to mimic the genome and population structure of a swine and cattle population undergoing selection on an index comprised of the estimated breeding values (EBV) for 2 genetically correlated quantitative traits. Ten generations were generated and genotyping began generation 7. Two phenotyping scenarios were simulated that assumed the first trait was recorded early in life on all individuals and the second trait was recorded on all versus a random subset of the individuals. The EBV were generated from a bivariate animal model. Multiple genotyping scenarios were generated that ranged from not genotyping any selection candidates, a proportion of the selection candidates based on either their index value or chosen at random, and genotyping all selection candidates. An interim index value was utilized to decide who to genotype for the selective genotype strategy. The interim value assumed only the first trait was observed and the only genotypic information available was on animals in previous generations. Within each genotyping scenario 25 replicates were generated. Within each genotyping scenario the mean response per generation and the degree to which EBV were inflated/deflated was calculated. Across both species and phenotyping strategies, the plateau of diminishing returns was observed when 60% of the selection candidates with the largest index values were genotyped. When randomly genotyping selection candidates, either 80 or 100% of the selection candidates needed to be genotyped for there not to be a reduction in the index response. Across both populations, no differences in the degree that EBV were inflated/deflated for either trait 1 or 2 were observed between nongenotyped and genotyped animals. The current study has shown that animals can be selectively genotyped in order to optimize the response to selection as a function of the cost to conduct a breeding program using single-step genomic best linear unbiased prediction
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