281 research outputs found

    Biogeographische, morphologische und molekularbiologische Untersuchungen zum Artstatus von Acalles temperei Péricart, 1987 und Kyklioacalles navieresi (Boheman, 1837)

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    Neben biogeographischen werden morphologische Argumente zusammengetragen, die für eine Synonymisierung der Arten Acalles parvulus Boheman, 1837 = Acalles temperei Péricart, 1987 sprechen. Entlang eines Transekts zwischen dem Mont Pilat (Dep. Loire) und dem Mont Saint-Martin nördlich von Grenoble (Dep. Isère) wird über den Vergleich der Aedoeagi eine Cline sichtbar, die am Artstatus von Acalles temperei zweifeln lässt. Bestätigung finden diese vergleichenden, phänotypischen Untersuchungen durch erste molekulargenetische Untersuchungen. Danach scheint entweder eine Hybridisierungszone wahrscheinlich oder der Verdacht liegt nahe, dass Acalles parvulus und Acalles temperei eine einzige, geographisch strukturierte Art darstellen. Völlig anders liegen die molekularbiologischen Ergebnisse bei Kyklioacalles roboris (Curtis, 1834) und der erst kürzlich resynonymisierten Art Kyklioacalles navieresi (Boheman, 1837): Die DNA-Sequenzanalysen der mitochondrialen CO1- und 16S-Gene sowie des nukleären 28S-Gens zeigen, dass Kyklioacalles navieresi und Kyklioacalles roboris zwei eigenständige, wenn auch eng verwandte Arten darstellen.New insights from biogeography, morphology and molecular biology: the species status of Acalles temperei Péricart, 1987 and Kyklioacalles navieresi (Boheman, 1837) (Curculionidae: Cryptorhynchinae); including 14 colored photographies, 2 plates, 1 diagram and 8 distribution maps. Biogeographical and morphological arguments are presented that suggest the following synonymization: Acalles parvulus Boheman, 1837 = Acalles temperei Péricart, 1987. Comparing the aedeagi along a transect from Mont Pilat (Dep. Loire) to Mont Saint-Martin North of Grenoble (Dep. Isère), a cline becomes apparent that raises doubts about the species status of Acalles temperei. These results, obtained by comparative phenotypic examination, are corroborated in a preliminary set of molecular genetic analyses. The latter either hint the existence of a hybrid zone or indicate that Acalles parvulus and Acalles temperei constitute a single, geographically structured species. The molecular results for Kyklioacalles roboris (Curtis, 1834) and the recently resynonymized species Kyklioacalles navieresi (Boheman, 1837) are very different. DNA sequence analysis of the mitochondrial CO1 and 16S genes and of the nuclear 28S gene showed that Kyklioacalles navieresi and Kyklioacalles roboris likely represent two individual, but closely related species

    Barcoding and interspecific relationships of Macaronesian Weevils (Coleoptera: Curculionoidea)

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    In dieser integrativ-taxonomischen Studie werden für 468 der 735 bisher beschriebenen lauri-makaronesischen Arten und Unterarten der Rüsselkäfer (Curculionoidea) mitochondriale CO1-Barcodes in 1388 Proben vorgelegt. Ein Bayes‘scher Baum (elektronisches Supplement) gibt Einblicke in die Beziehungen innerhalb der Arten und Unterarten, ohne ein phylogenetisches Gesamtbild oberhalb der Gattungsebene anzustreben. Mit Ausnahme einiger weniger diskutierter Fälle erlaubt der vorliegende Datensatz von DNA-Barcodes eine zuverlässige Re-Identifizierung und bemerkenswerte Differenzierung von Arten und wird die Entdeckung und Beschreibung neuer Rüsselkäfer-Arten - sowie deren (Re-) Synonymisierung - von den Kanaren, Madeira, und den Azoren beschleunigen. Nur in einem einzigen Fall, bei den eingewanderten, verwandten Arten Rhinoncus castor und R. bruchoides (Ceutorhynchinae) aus Madeira, ergab die molekulare (Re-)Identifizierung einen unauflösbaren Widerspruch zu unserer morphologischen Artbestimmung. In den meisten Fällen wurden die morphologischen Bestimmungen zuvor durch Vergleiche mit dem Typenmaterial untermauert und sequenzierte Exemplare wurden in einer Referenzsammlung für spätere Nachbestimmungen hinterlegt.In an integrative taxonomic approach, this study presents mitochondrial CO1 barcodes for 468 of the 735 so far described Lauri-Macaronesian weevil (Curculionoidea) species and subspecies in 1388 samples. A Bayesian tree (electronic supplement) provides insights into within-species relationships, without aiming at phylogenetic accuracy above genus level. With the exception of a few discussed cases, the present dataset of DNA barcodes allows a reliable re-identification and remarkable differentiation of species and will accelerate the discovery of new weevil species from the Canary, Madeira and Azores archipelagos. Only in a single case, the similar species Rhinoncus castor and R. bruchoides (Ceutorhynchinae) from Madeira, did the molecular (re)identification reveal an unresolvable contradiction with our morphological species identification. In many cases, morphological determinations were bolstered by comparisons with the type material. Sequenced specimens were mounted and deposited in a reference collection for later re-determinations

    Meson decay constants from Nf=2 clover fermions

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    We present recent results for meson decay constants calculated on configurations with two flavours of O(a)-improved Wilson fermions. Non-perturbative renormalisation is applied and quark mass dependencies as well as finite volume and discretisation effects are investigated. In this work we also present a computation of the coupling of the light vector mesons to the tensor current using dynamical fermions.Comment: 6 pages, contribution to Lattice2005(Hadron spectrum and quark masses

    A determination of the strange quark mass for unquenched clover fermions using the AWI

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    Using the O(a) Symanzik improved action an estimate is given for the strange quark mass for unquenched (nf=2) QCD. The determination is via the axial Ward identity (AWI) and includes a non-perturbative evaluation of the renormalisation constant. Numerical results have been obtained at several lattice spacings, enabling the continuum limit to be taken. Results indicate a value for the strange quark mass (in the MSbar-scheme at a scale of 2GeV) in the range 100 - 130MeV.Comment: 6 pages, contribution to Lattice2005(Hadron spectrum and quark masses), uses PoS.cl

    Molecular and morphological systematics of soil-inhabiting Cryptorhynchinae of the genus Acallorneuma and the tribe Torneumatini (Coleoptera: Curculionidae), with description of two new species.

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    Ausgehend von ökologischen (idealtypischen) Einordnungen der flugunfähigen, westpaläarktischen Cryptorhynchinae werden molekulare und morphologische Ergebnisse zur monophyletischen Rüsselkäfer-Gattung Acallorneuma Mainardi, 1906 und zu den subterrestrisch lebenden Arten des Tribus Torneumatini Bedel, 1884 vorgestellt. Ein Katalog und ein Bilderschlüssel zu den 8 validen Arten der Acallorneuma leitet eine Diskussion über die begrenzten Möglichkeiten einer rein morphologischen Analyse der uniformen Arten des Genus Acallorneuma ein. In einem weiteren Schritt wird die morphologische Systematik mit der molekularen Rekonstruktion der Verwandtschaftsverhältnisse anhand einer Region des mitochondrialen CO1 Gens verglichen. Im zweiten Teil der Arbeit wenden wir uns den gegenwärtig 71 bekannten, blinden, flügellosen und weitgehend kryptischen, tief im Erdreich lebenden Arten der Torneumatini zu. Die molekulare Analyse zeigt zwischen den Arten erhebliche p-Distanzen, macht aber auch deutlich, dass die Rekonstruktion der Verwandtschaftsverhältnisse ganz entscheidend von der Anzahl der Arten und Proben abhängig ist. Dennoch wurden einige taxonomische Änderungen vorgenommen: Torneuma s. str. mit der Typusart Torneuma caecum Wollaston, 1860 gibt es nur auf dem Madeira Archipel! Die Arten des Subgenus Paratyphloporus Solari, 1937 stat. nov. – und zwar nur die von den Kanarischen Inseln – gehören in das Subgenus Paratorneuma Roudier, 1956 stat. nov. Für alle anderen Arten aus dem mediterranen Gebiet und den östlichen kanarischen Inseln ist eine endgültige Klassifikation zur Zeit noch nicht möglich (incertae sedis), auch wenn erste Gruppen - eingeteilt vor allem nach der Innensackstruktur des Aedoeagus - hier bereits vorgestellt werden (siehe Anhang 2). Torneuma deplanatum deplanatum (Hampe, 1864) ist die Typusart des Subgenus Typhloporus und schließt einige, aber eben nicht alle mediterranen Arten mit einem konstant tiefen Rüsselkanal ein, der – das zeigen unsere vergleichenden Studien – offensichtlich mehrere Male in der Evolution ausgebildet wurde. Zwei neue Arten werden abschließenden beschrieben: Torneuma (s. str.) isambertoi Stüben spec. nov. von Madeira and Torneuma (s.l.) cadizensis Stüben spec. nov. aus dem Süden Spaniens. Für beide Arten werden Schlüssel mit den nächst verwandten Arten präsentiert.StichwörterAcallorneuma, Torneumatini, Torneuma, Bayesian analysis, Integrative Taxonomy, morphology, CO1, new species, taxonomic changes, Western Palaearctic, Spain, Portugal, Canary Islands, Madeira.Nomenklatorische Handlungenisambertoi Stüben, 2016 (Torneuma (s. str.)), spec. nov.cadizensis Stüben, 2016 (Torneuma (s.l.)), spec. nov.Starting from an ecological classification of the morphotypes of apterous western Palaearctic Cryptorhynchinae, molecular systematic and morphological results for the monophyletic weevil genus Acallorneuma Mainardi, 1906 and the tribe Torneumatini Bedel, 1884 are presented. Based on the mitochondrial CO1 barcoding region, we discuss the limits of comparative morphology in the uniform Acallorneuma species. A catalogue and a pictorial key of all 8 species of Acallorneuma are provided. In a second step we compare morphology-based systematics of the genus Acallorneuma with our molecular reconstruction. Finally, we focus on the related blind, equally wingless and uniform, currently 71 species of the tribe Torneumatini living deep in the soil. This overview of the present state of research shows that molecular intrageneric resolution is highly dependent on the number of sampled species, especially in those cases with particularly long edges in the dendrogram. But although Torneumatini sampling was not complete due to the elusiveness of these subterranean species, some taxonomic changes could still be implemented: Torneuma s. str. with the type species Torneuma caecum Wollaston, 1860 occurs only on the Madeira archipelago. The species of the subgenus Paratyphloporus Solari, 1937 stat. nov. - only from the western Canary Islands(!) - must be transferred into the genus subgenus Paratorneuma Roudier, 1956 stat. nov. For all other species of the Mediterranean area and the eastern Canary Islands, the systematic classification needs to be remade (incertae sedis, see also appendix 2). Torneuma deplanatum deplanatum (Hampe, 1864) is the type species of the subgenus Typhloporus that includes some, but not all Mediterranean species with a constantly deep and wide pectoral canal, which - as it now seems likely – was developed several times. Two new species are described: Torneuma (s. str.) isambertoi Stüben spec. nov. from Madeira and Torneuma (s.l.) cadizensis Stüben spec. nov. from the south of Spain. In both cases keys are given to differentiate from the closely related species.KeywordsAcallorneuma, Torneumatini, Torneuma, Bayesian analysis, Integrative Taxonomy, morphology, CO1, new species, taxonomic changes, Western Palaearctic, Spain, Portugal, Canary Islands, Madeira.Nomenclatural Actsisambertoi Stüben, 2016 (Torneuma (s. str.)), spec. nov.cadizensis Stüben, 2016 (Torneuma (s.l.)), spec. nov

    A Scheme to Numerically Evolve Data for the Conformal Einstein Equation

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    This is the second paper in a series describing a numerical implementation of the conformal Einstein equation. This paper deals with the technical details of the numerical code used to perform numerical time evolutions from a "minimal" set of data. We outline the numerical construction of a complete set of data for our equations from a minimal set of data. The second and the fourth order discretisations, which are used for the construction of the complete data set and for the numerical integration of the time evolution equations, are described and their efficiencies are compared. By using the fourth order scheme we reduce our computer resource requirements --- with respect to memory as well as computation time --- by at least two orders of magnitude as compared to the second order scheme.Comment: 20 pages, 12 figure

    Connected and disconnected quark contributions to hadron spin

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    By introducing an external spin operator to the fermion action, the quark spin fractions of hadrons are determined from the linear response of the hadron energies using the Feynman-Hellmann (FH) theorem. At our SU(3)-flavour symmetric point, we find that the connected quark spin fractions are universally in the range 55-70\% for vector mesons and octet and decuplet baryons. There is an indication that the amount of spin suppression is quite sensitive to the strength of SU(3) breaking. We also present first preliminary results applying the FH technique to calculations of quark-line disconnected contributions to hadronic matrix elements of axial and tensor operators. At the SU(3)-flavour symmetric point we find a small negative contribution to the nucleon spin from disconnected quark diagrams, while the corresponding tensor matrix elements are consistent with zero.Comment: 7 pages, 5 figures, 32nd International Symposium on Lattice Field Theor

    Investigation of the Second Moment of the Nucleon's g1 and g2 Structure Functions in Two-Flavor Lattice QCD

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    The reduced matrix elements a_2 and d_2 are computed in lattice QCD with N_f=2 flavors of light dynamical (sea) quarks. For proton and neutron targets we obtain as our best estimates d_2^(p)=0.004(5) and d_2^(n)=-0.001(3), respectively, in the MSbar scheme at Q^2=5 GeV^2, while for a_2 we find a_2^(p)=0.077(12) and a_2^(n)=-0.005(5), where the errors are purely statistical.Comment: 9 pages, 9 figures, 5 tables, revised version: estimate of systematic uncertainty in chiral extrapolation, 2 references added, version to appear in Phys.Rev.

    A lattice determination of Sigma - Lambda mixing

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    Isospin breaking effects in baryon octet (and decuplet) masses are due to a combination of up and down quark mass differences and electromagnetic effects and lead to small mass splittings. Between the Sigma and Lambda this mass splitting is much larger, this being mostly due to their different wavefunctions. However when isospin is broken, there is a mixing between between these states. We describe the formalism necessary to determine the QCD mixing matrix and hence find the mixing angle and mass splitting between the Sigma and Lambda particles due to QCD effects.Comment: 40 pages, 5 figures, published versio

    Hyperon Form Factors from N_f=2+1 QCD

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    We present results from the QCDSF/UKQCD collaboration for the electromagnetic and semi-leptonic form factors for the hyperons. The simulations are performed on our new ensembles generated with 2+1 flavours of dynamical O(a)-improved Wilson fermions. A unique feature of these configurations is that the quark masses are tuned so that the singlet quark mass is held fixed at its physical value. We use 5 such choices of the individual quark masses on 24^3x48 lattices with a lattice spacing of about 0.078 fm.Comment: 7 pages, 6 figures, 1 table. Talk presented at The XXVIII International Symposium on Lattice Field Theory, Villasimius, Italy, 14-19 June 201
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