4,744 research outputs found

    Garden varieties: how attractive are recommended garden plants to butterflies?

    Get PDF
    One way the public can engage in insect conservation is through wildlife gardening, including the growing of insect-friendly flowers as sources of nectar. However, plant varieties differ in the types of insects they attract. To determine which garden plants attracted which butterflies, we counted butterflies nectaring on 11 varieties of summer-flowering garden plants in a rural garden in East Sussex, UK. These plants were all from a list of 100 varieties considered attractive to British butterflies, and included the five varieties specifically listed by the UK charity Butterfly Conservation as best for summer nectar. A total of 2659 flower visits from 14 butterfly and one moth species were observed. We performed a principal components analysis which showed contrasting patterns between the species attracted to Origanum vulgare and Buddleia davidii. The “butterfly bush” Buddleia attracted many nymphalines, such as the peacock, Inachis io, but very few satyrines such as the gatekeeper, Pyronia tithonus, which mostly visited Origanum. Eupatorium cannibinum had the highest Simpson’s Diversity score of 0.75, while Buddleia and Origanum were lower, scoring 0.66 and 0.50 respectively. No one plant was good at attracting all observed butterfly species, as each attracted only a subset of the butterfly community. We conclude that to create a butterfly-friendly garden, a variety of plant species are required as nectar sources for butterflies. Furthermore, garden plant recommendations can probably benefit from being more precise as to the species of butterfly they attract

    Marine turtle harvest in a mixed small-scale fishery: Evidence for revised management measures

    Get PDF
    Copyright © 2013 Elsevier. NOTICE: this is the author’s version of a work that was accepted for publication in Ocean and Coastal Management. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Ocean and Coastal Management, 2013, Vol. 82, pp. 34 – 42 DOI: http://dx.doi.org/10.1016/j.ocecoaman.2013.05.004Small-scale fisheries (SSF) account for around half of the world's marine and inland fisheries, but their impact on the marine environment is usually under-estimated owing to difficulties in monitoring and regulation. Successful management of mixed SSF requires holistic approaches that sustainably exploit target species, consider non-target species and maintain fisher livelihoods. For two years, we studied the marine turtle fishery in the Turks and Caicos Islands (TCI) in the Wider Caribbean Region, where the main export fisheries are queen conch (Strombus gigas) and the spiny lobster (Panulirus argus); with fin-fish, green turtles (Chelonia mydas) and hawksbill turtles (Eretmochelys imbricata) taken for domestic consumption. We evaluate the turtle harvest in relation to the other fisheries and recommend legislation and management alternatives. We demonstrate the connectivity between multi-species fisheries and artisanal turtle capture: with increasing lobster catch-per-unit-effort (CPUE), hawksbill catch increased whilst green turtle catch decreased. With increasing conch CPUE, hawksbill catch declined and there was no demonstrable effect on green turtle catch. We estimate 176–324 green and 114–277 hawksbill turtles are harvested annually in TCI: the largest documented legal hawksbill fishery in the western Atlantic. Of particular concern is the capture of adult turtles. Current legislation focuses take on larger individuals that are key to population maintenance. Considering these data we recommend the introduction of maximum size limits for both species and a closed season on hawksbill take during the lobster fishing season. Our results highlight the need to manage turtles as part of a broader approach to SSF management

    Effective computational methods for hybrid stochastic gene networks

    Full text link
    At the scale of the individual cell, protein production is a stochastic process with multiple time scales, combining quick and slow random steps with discontinuous and smooth variation. Hybrid stochastic processes, in particular piecewise-deterministic Markov processes (PDMP), are well adapted for describing such situations. PDMPs approximate the jump Markov processes traditionally used as models for stochastic chemical reaction networks. Although hybrid modelling is now well established in biology, these models remain computationally challenging. We propose several improved methods for computing time dependent multivariate probability distributions (MPD) of PDMP models of gene networks. In these models, the promoter dynamics is described by a finite state, continuous time Markov process, whereas the mRNA and protein levels follow ordinary differential equations (ODEs). The Monte-Carlo method combines direct simulation of the PDMP with analytic solutions of the ODEs. The push-forward method numerically computes the probability measure advected by the deterministic ODE flow, through the use of analytic expressions of the corresponding semigroup. Compared to earlier versions of this method, the probability of the promoter states sequence is computed beyond the naive mean field theory and adapted for non-linear regulation functions

    Electroweak Gauge-Boson Production at Small q_T: Infrared Safety from the Collinear Anomaly

    Get PDF
    Using methods from effective field theory, we develop a novel, systematic framework for the calculation of the cross sections for electroweak gauge-boson production at small and very small transverse momentum q_T, in which large logarithms of the scale ratio M_V/q_T are resummed to all orders. These cross sections receive logarithmically enhanced corrections from two sources: the running of the hard matching coefficient and the collinear factorization anomaly. The anomaly leads to the dynamical generation of a non-perturbative scale q_* ~ M_V e^{-const/\alpha_s(M_V)}, which protects the processes from receiving large long-distance hadronic contributions. Expanding the cross sections in either \alpha_s or q_T generates strongly divergent series, which must be resummed. As a by-product, we obtain an explicit non-perturbative expression for the intercept of the cross sections at q_T=0, including the normalization and first-order \alpha_s(q_*) correction. We perform a detailed numerical comparison of our predictions with the available data on the transverse-momentum distribution in Z-boson production at the Tevatron and LHC.Comment: 34 pages, 9 figure

    Effect of preoperative thoracic duct drainage on canine kidney transplantation

    Get PDF
    Chronic drainage of the thoracic duct to the esophagus was developed in dogs, and its efficacy in immunomodulation was tested using kidney transplantation. Compared to 9.7 days in the control, the mean animal survival was prolonged to 9.9 days, 17.8 days, and 18.5 days when TDD was applied preoperatively for 3 weeks, 6 weeks, and 9 weeks, respectively. Prolongation was significant after 6 weeks. Patency of the fistula was 93.5, 80.4, and 76.1% at respective weeks. Number of peripheral T-lymphocytes determined by a new monoclonal antibody diminished after 3 weeks. All animals were in normal health, requiring no special care for fluid, electrolyte, or protein replacement

    Gene mobility promotes the spread of resistance in bacterial populations

    Get PDF
    Theory predicts that horizontal gene transfer (HGT) expands the selective conditions under which genes spread in bacterial populations. Whereas vertically inherited genes can only spread by positively selected clonal expansion, mobile genetic elements can drive fixation of genes by infectious HGT. We tested this using populations of Pseudomonas fluorescens and the conjugative mercury resistance (Hg R) plasmid pQBR57. HGT expanded the selective conditions allowing the spread of Hg R: Chromosomal Hg R only increased in frequency under positive selection, whereas plasmid-encoded Hg R reached fixation with or without positive selection. Tracking plasmid dynamics over time revealed that the mode of Hg R inheritance varied across mercury environments. Under mercury selection, the spread of Hg R was driven primarily by clonal expansion while in the absence of mercury Hg R dynamics were dominated by infectious transfer. Thus, HGT is most likely to drive the spread of resistance genes in environments where resistance is useless

    Integrative analysis of the microbiome and metabolome of the human intestinal mucosal surface reveals exquisite inter-relationships

    Get PDF
    Background: Consistent compositional shifts in the gut microbiota are observed in IBD and other chronic intestinal disorders and may contribute to pathogenesis. The identities of microbial biomolecular mechanisms and metabolic products responsible for disease phenotypes remain to be determined, as do the means by which such microbial functions may be therapeutically modified. Results: The composition of the microbiota and metabolites in gut microbiome samples in 47 subjects were determined. Samples were obtained by endoscopic mucosal lavage from the cecum and sigmoid colon regions, and each sample was sequenced using the 16S rRNA gene V4 region (Illumina-HiSeq 2000 platform) and assessed by UPLC mass spectroscopy. Spearman correlations were used to identify widespread, statistically significant microbial-metabolite relationships. Metagenomes for identified microbial OTUs were imputed using PICRUSt, and KEGG metabolic pathway modules for imputed genes were assigned using HUMAnN. The resulting metabolic pathway abundances were mostly concordant with metabolite data. Analysis of the metabolome-driven distribution of OTU phylogeny and function revealed clusters of clades that were both metabolically and metagenomically similar. Conclusions: The results suggest that microbes are syntropic with mucosal metabolome composition and therefore may be the source of and/or dependent upon gut epithelial metabolites. The consistent relationship between inferred metagenomic function and assayed metabolites suggests that metagenomic composition is predictive to a reasonable degree of microbial community metabolite pools. The finding that certain metabolites strongly correlate with microbial community structure raises the possibility of targeting metabolites for monitoring and/or therapeutically manipulating microbial community function in IBD and other chronic diseases

    Direct photon production with effective field theory

    Get PDF
    The production of hard photons in hadronic collisions is studied using Soft-Collinear Effective Theory (SCET). This is the first application of SCET to a physical, observable cross section involving energetic partons in more than two directions. A factorization formula is derived which involves a non-trivial interplay of the angular dependence in the hard and soft functions, both quark and gluon jet functions, and multiple partonic channels. The relevant hard, jet and soft functions are computed to one loop and their anomalous dimensions are determined to three loops. The final resummed inclusive direct photon distribution is valid to next-to-next-to-leading logarithmic order (NNLL), one order beyond previous work. The result is improved by including non-logarithmic terms and photon isolation cuts through matching, and compared to Tevatron data and to fixed order results at the Tevatron and the LHC. The resummed cross section has a significantly smaller theoretical uncertainty than the next-to-leading fixed-order result, particularly at high transverse momentum.Comment: 42 pages, 9 figures; v2: references added, minor changes; v3: typos; v4: typos, corrections in (16), (47), (72

    Characterization of dry-stack interlocking compressed earth blocks

    Get PDF
    Earth has been a traditional building material to construct houses in Africa. One of the most common techniques is the use of sun dried or kiln fired adobe bricks with mud mortar. Fired bricks are the main cause for deforestation in countries like Malawi. Although this technique is low-cost, the bricks vary largely in shape, strength and durability. This leads to weak houses which suffer considerable damage during floods and seismic events. One solution is the use of dry-stack masonry with stabilized interlocking compressed earth blocks (ICEB). This technology has the potential of substituting the current bricks by a more sustainable kind of block. This study was made in the context of the HiLoTec project, which focuses on houses in rural areas of developing countries. For this study, Malawi was chosen for a case study. This paper presents the experimental results of tests made with dry-stack ICEBs. Soil samples from Malawi were taken and studied. Since the experimental campaign could not be carried out in Malawi, a homogenization process of Portuguese soil was made to produce ICEBs at the University of Minho, Portugal. Then, the compression and tensile strength of the materials was determined via small cylinder samples. Subsequently, the compression and flexural strength of units were determined. Finally, tests to determine the compressive strength of both prisms and masonry wallets and to determine the initial shear strength of the dry interfaces were carried out. This work provides valuable data for low-cost eco-efficient housingThis work was carried out under the research project HiLoTec - Development of a Sustainable Self-Construction System for Developing Countries. The authors wish to thank Mota-Engil Constructing Group for supporting this project
    corecore