791 research outputs found

    Toxic Phenolic Glycosides From \u3ci\u3ePopulus:\u3c/i\u3e Physiological Adaptations of the Western North American Tiger Swallowtail Butterfly, \u3ci\u3ePapilio Rutulus\u3c/i\u3e (Lepidoptera: Papilionidae)

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    The phenolic glycosides tremulacin and salicortin found in quaking aspen, Populus tremuloides, and other members of the Salicaceae, are known to be toxic to larvae of the Eastern tiger swallowtail butterfly, Papilio glaucus, but not to the Canadian tiger swallowtail, P. canadensis. Larvae of the western tiger swallowtail, P. rutulus, were not killed nor were their growth rates suppressed when fed a mixture of tremulacin and salicortin on black cherry leaves. When the Salicaceae adapted P. rutulus penultimate instar larvae were fed a combination of the two phenolic glycosides and the esterase inhibitor (DEF S,S,S-tributylphosphorotrithioate), growth was reduced more than 50OJo compared to controls, and half of the larvae died before completing the instaL Our results indicate that esterase detoxification mechanisms are involved in the western tiger swallowtail, P. rutulus, as is also known to be the case for the northern tiger swallowtail, P. canadensis. It is not known whether the same esterase isozyme is involved in both species. From an evolutionary perspective such information could help resolve whether the Salicaceae-adapted swallowtails species are a monophyletic group (perhaps due to isolation in the Beringial Pleistocene glacial refuge of Alaska)

    Toxic Phenolic Glycosides From \u3ci\u3ePopulus:\u3c/i\u3e Physiological Adaptations of the Western North American Tiger Swallowtail Butterfly, \u3ci\u3ePapilio Rutulus\u3c/i\u3e (Lepidoptera: Papilionidae)

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    The phenolic glycosides tremulacin and salicortin found in quaking aspen, Populus tremuloides, and other members of the Salicaceae, are known to be toxic to larvae of the Eastern tiger swallowtail butterfly, Papilio glaucus, but not to the Canadian tiger swallowtail, P. canadensis. Larvae of the western tiger swallowtail, P. rutulus, were not killed nor were their growth rates suppressed when fed a mixture of tremulacin and salicortin on black cherry leaves. When the Salicaceae adapted P. rutulus penultimate instar larvae were fed a combination of the two phenolic glycosides and the esterase inhibitor (DEF S,S,S-tributylphosphorotrithioate), growth was reduced more than 50OJo compared to controls, and half of the larvae died before completing the instaL Our results indicate that esterase detoxification mechanisms are involved in the western tiger swallowtail, P. rutulus, as is also known to be the case for the northern tiger swallowtail, P. canadensis. It is not known whether the same esterase isozyme is involved in both species. From an evolutionary perspective such information could help resolve whether the Salicaceae-adapted swallowtails species are a monophyletic group (perhaps due to isolation in the Beringial Pleistocene glacial refuge of Alaska)

    EU Peatlands: Current Carbon Stocks and Trace Gas Fluxes

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    Peatlands in Europe has formed a significant sink for atmospheric CO2 since the last glacial maximum. Currently they are estimated to hold ca. 42 Gt carbon in the form of peat and are therefore a considerable component in the European carbon budget. Due to the generally wet soil conditions in peatlands they are also significant emitters of the strong greenhouse gas (GHG) methane (CH4) and in some cases also of nitrous oxide (N2O). The EU funded CarboEurope-GHG Concerted Action attempts to develop a reliable and complete greenhouse gas budget for Europe and this report aims to provide a review and synthesis of the available information about GHG exchanges in European peatlands and their underlying processes. A best estimate for all the European countries shows that some are currently sinks for atmospheric CO2 while others are sources. In contrast, for CH4 and N2O, only the sources are relevant. Whilst some countries are CO2 sinks, all countries are net GHG emitters from peatlands. The results presented, however, carry large uncertainties, which cannot be adequately quantified yet. One outstanding uncertainty is the distribution of land use types, particular in Russia, the largest European peat nation. The synthesis of GHG exchange, nevertheless, indicates some interesting features. Russia hosts an estimated 41% of European peatlands and contributes most to all GHG exchanges (CO2: 25%, CH4: 52%, N2O: 26%, Total: 37%). Germany is the second-largest emitter (12% of European total) although it contains only 3.2% of European peatlands. The reason is the use of most of the peatland area for intensive cropland and grassland. The largest CO2 emitters are countries with large agricultural peatland areas (Russia, Germany, Belarus, Poland), the largest N2O emitters are those with large agricultural fen areas (Russia, Germany, Finland). In contrast, the largest CH4 emitters are concentrated in regions with large areas of intact mires, namely Russia and Scandinavia. High average emission densities above 3.5 t C-equiv. ha-1 are found in the Southeast Mediterranean, Germany and the Netherlands where agricultural use of peatlands is intense. Low average emission densities below 0.3 t C-equiv. ha-1 occur where mires and peatland forests dominate, e.g. Finland and the UK. This report concludes by pointing at key gaps in our knowledge about peatland carbon stocks and GHG exchanges which include insufficient basic information on areal distribution of peatlands, measurements of peat depth and also a lack of flux datasets providing full annual budgets of GHG exchanges

    Resonance structure in the Li^- photodetachment cross section

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    We report on the first observation of resonance structure in the total cross section for the photodetachment of Li^-. The structure arises from the autodetaching decay of doubly excited ^1P states of Li^- that are bound with respect to the 3p state of the Li atom. Calculations have been performed for both Li^- and H^- to assist in the identification of these resonances. The lowest lying resonance is a symmetrically excited intrashell resonance. Higher lying asymmetrically excited intershell states are observed which converge on the Li(3p) limit.Comment: 4 pages, 2 figure, 19 references, RevTeX, figures in ep

    A High-Resolution Genetic Map of Yellow Monkeyflower Identifies Chemical Defense QTLs and Recombination Rate Variation

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    Genotyping-by-sequencing methods have vastly improved the resolution and accuracy of genetic linkage maps by increasing both the number of marker loci as well as the number of individuals genotyped at these loci. Using restriction-associated DNA sequencing, we construct a dense linkage map for a panel of recombinant inbred lines derived from a cross between divergent ecotypes of Mimulus guttatus. We used this map to estimate recombination rate across the genome and to identify quantitative trait loci for the production of several secondary compounds (PPGs) of the phenylpropanoid pathway implicated in defense against herbivores. Levels of different PPGs are correlated across recombinant inbred lines suggesting joint regulation of the phenylpropanoid pathway. However, the three quantitative trait loci identified in this study each act on a distinct PPG. Finally, we map three putative genomic inversions differentiating the two parental populations, including a previously characterized inversion that contributes to life-history differences between the annual/perennial ecotypes.We thank M. Montenero and K. Keefover-Ring for assistance in phytochemistry sample preparation and HPLC troubleshooting, respectively. The KU EEB Genetics group provided valuable comments on the manuscript. We also thank Emma Huang and two anonymous reviewers for their comments. Funding for this research was provided by National Science Foundation grants DEB-0841609 (to RLL) and IOS-0951254 (to J.K.K.), by NIH grant GM073990 (to J.K.K.), and funding from the University of Kansas Botany Endowment Funds (to P.J.M.)

    CP-odd Phase Correlations and Electric Dipole Moments

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    We revisit the constraints imposed by electric dipole moments (EDMs) of nucleons and heavy atoms on new CP-violating sources within supersymmetric theories. We point out that certain two-loop renormalization group corrections induce significant mixing between the basis-invariant CP-odd phases. In the framework of the constrained minimal supersymmetric standard model (CMSSM), the CP-odd invariant related to the soft trilinear A-phase at the GUT scale, theta_A, induces non-trivial and distinct CP-odd phases for the three gaugino masses at the weak scale. The latter give one-loop contributions to EDMs enhanced by tan beta, and can provide the dominant contribution to the electron EDM induced by theta_A. We perform a detailed analysis of the EDM constraints within the CMSSM, exhibiting the reach, in terms of sparticle spectra, which may be obtained assuming generic phases, as well as the limits on the CP-odd phases for some specific parameter points where detailed phenomenological studies are available. We also illustrate how this reach will expand with results from the next generation of experiments which are currently in development.Comment: 31 pages, 21 eps figures; v2: additional remarks on 2-loop threshold corrections and references added; v3: typos corrected, to appear in Phys. Rev.

    Two--Electron Atoms in Short Intense Laser Pulses

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    We discuss a method of solving the time dependent Schrodinger equation for atoms with two active electrons in a strong laser field, which we used in a previous paper [A. Scrinzi and B. Piraux, Phys. Rev. A 56, R13 (1997)] to calculate ionization, double excitation and harmonic generation in Helium by short laser pulses. The method employs complex scaling and an expansion in an explicitly correlated basis. Convergence of the calculations is documented and error estimates are provided. The results for Helium at peak intensities up to 10^15 W/cm^2 and wave length 248 nm are accurate to at least 10 %. Similarly accurate calculations are presented for electron detachment and double excitation of the negative hydrogen ion.Comment: 14 pages, including figure

    Macroecology of ground beetles : Species richness, range size and body size show different geographical patterns across a climatically heterogeneous area

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    Aim Ecogeographical patterns have been widely studied in endothermic vertebrates, but relatively few studies have simultaneously examined patterns and causes of gradients in species richness, range size and body size in ectothermic insects. We examined patterns in species richness, mean range size and mean body size of ground beetle assemblages across the biogeographical provinces of Northern Europe, a region that was mostly covered by ice sheets during the latest Ice Age and that presents strong contemporary climatic gradients. Location Northern Europe. Methods We used literature information on the occurrence of ground beetles, and analysed patterns in species richness, mean range size and mean body size across the provinces using generalized linear models and boosted regression tree (BRT) analysis. Results We found a strongly decreasing gradient in species richness with increasing latitude, a strongly unimodal range size-latitude relationship, and a weak unimodal body size-latitude relationship in entire ground beetle assemblages. These gradients also varied among four major genera, suggesting that the overall patterns result from the nuances of smaller clades of ground beetles. The relative importance of contemporary environmental drivers also varied between species richness, mean range size and mean body size in BRT analysis. While species richness increased with mean annual temperature, mean range size showed an opposite relationship. Mean body size was most clearly associated with the precipitation of the driest month. Main Conclusions Our findings showed that the latitudinal species richness gradient was strong, and it was closely related to concomitant variation in temperature, whereas variations in mean range size and mean body size were more complex. These findings suggest that the causes for range size and body size variation in insects may be complex, requiring additional insights from studies conducted at local, regional and continental scales

    Association between plasma tau and postoperative delirium incidence and severity: a prospective observational study

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    BACKGROUND: Postoperative delirium is associated with increases in the neuronal injury biomarker, neurofilament light (NfL). Here we tested whether two other biomarkers, glial fibrillary acidic protein (GFAP) and tau, are associated with postoperative delirium. METHODS: A total of 114 surgical patients were recruited into two prospective biomarker cohort studies with assessment of delirium severity and incidence. Plasma samples were sent for biomarker analysis including tau, NfL, and GFAP, and a panel of 10 cytokines. We determined a priori to adjust for interleukin-8 (IL-8), a marker of inflammation, when assessing associations between biomarkers and delirium incidence and severity. RESULTS: GFAP concentrations showed no relationship to delirium. The change in tau from preoperative concentrations to postoperative Day 1 was greater in patients with postoperative delirium (P<0.001) and correlated with delirium severity (ρ=0.39, P<0.001). The change in tau correlated with increases in IL-8 (P<0.001) and IL-10 (P=0.0029). Linear regression showed that the relevant clinical predictors of tau changes were age (P=0.037), prior stroke/transient ischaemic attack (P=0.001), and surgical blood loss (P<0.001). After adjusting for age, sex, preoperative cognition, and change in IL-8, tau remained significantly associated with delirium severity (P=0.026). Using linear mixed effect models, only tau (not NfL or IL-8) predicted recovery from delirium (P<0.001). CONCLUSIONS: The change in plasma tau was associated with delirium incidence and severity, and resolved over time in parallel with delirium features. The impact of this putative perioperative neuronal injury biomarker on long-term cognition merits further investigation. CLINICAL TRIAL REGISTRATION: NCT02926417 and NCT03124303

    Phylogenetic Relationships of Tribes Within Harpalinae (Coleoptera: Carabidae) as Inferred from 28S Ribosomal DNA and the Wingless Gene

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    Harpalinae is a large, monophyletic subfamily of carabid ground beetles containing more than 19,000 species in approximately 40 tribes. The higher level phylogenetic relationships within harpalines were investigated based on nucleotide data from two nuclear genes, wingless and 28S rDNA. Phylogenetic analyses of combined data indicate that many harpaline tribes are monophyletic, however the reconstructed trees showed little support for deeper nodes. In addition, our results suggest that the Lebiomorph Assemblage (tribes Lebiini, Cyclosomini, Graphipterini, Perigonini, Odacanthini, Lachnophorini, Pentagonicini, Catapiesini and Calophaenini), which is united by a morphological synapomorphy, is not monophyletic, and the tribe Lebiini is paraphyletic with respect to members of Cyclosomini. Two unexpected clades of tribes were supported: the Zuphiitae, comprised of Anthiini, Zuphiini, Helluonini, Dryptini, Galeritini, and Physocrotaphini; and a clade comprised of Orthogoniini, Pseudomorphini, and Graphipterini. The data presented in this study represent a dense sample of taxa to examine the molecular phylogeny of Harpalinae and provide a useful framework to examine the origin and evolution of morphological and ecological diversity in this group
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