513 research outputs found

    Fifty-four State Records of True Bugs (Hemiptera: Heteroptera) from Arkansas

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    The terrestrial true bug (Hemipterar: Heteroptera) fauna of Arkansas is poorly represented in the literature. Between 1998 and 2004, we retained Hemiptera specimens collected while conducting a few scattered entomological projects. Ninety-nine species of terrestrial Hemiptera, representing 15 families, were collected from various locations within 9 Arkansas counties. Of these 99 species, 54 are new state records for Arkansas. The majority of these 54 new state records are of common, widespread species that would be expected for Arkansas. Twenty-two of the 54 species have been reported for at least 4 states bordering Arkansas, whereas only 5 species (all Miridae) were not previously reported for any bordering state. Our specimens of Pycnoderes convexicollis (Blatchley, 1926) represent a fairly significant range extension for this species, previously known only from Indiana and Illinois

    One-loop calculations for SUSY processes

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    Strategy and results for complete one-loop computations in the Minimal Supersymmetric Standard Model are reviewed, with applications to the calculation of SUSY mass spectra and SUSY-particle processes. Determination of renormalization constants and counterterms are described in the on-shell renormalization scheme, and a translation between DRˉ\bar{\rm DR} and on-shell parameters is given. As an example, cross sections for chargino and neutralino pair production in e+e−e^+e^- annihilation are presented, complete at the one-loop level.Comment: Talk presented at Loops and Legs in Quantum Field Theory, Zinnowitz, Germany, April 200

    Insects Inhabiting the Burrows of the Ozark Pocket Gopher in Arkansas

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    Pocket gopher burrows provide a stable environment for a variety of inquilines; hence this mammal is regarded as a keystone species. Most of the arthropods inhabiting pocket gopher burrows are restricted to this microhabitat. As part of a planned state-wide biotic survey of insects inhabiting this unusual microhabitat, we have focused our initial sampling efforts on the Ozark pocket gopher (Geomys bursarius ozarkensis; Geomyidae). In 2004 and 2005, pitfall traps were established in pocket gopher burrows and in 2007 and 2008, nests and associated chambers were excavated. Retrieved samples contained scarab, histerid, and rove beetles, cave crickets and anthomyiid flies. The histerids consisted of five species, one of which is undescribed, and all of which are new state records. A total of five species of scarab beetles were collected and all of these represent new state records. Two species of cave crickets were collected; one appears to be undescribed, and the other is essentially a Great Plains species and represents a considerable range extension. Both crickets are new to Arkansas

    Eigenvalue Bounds for Perturbations of Schrodinger Operators and Jacobi Matrices With Regular Ground States

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    We prove general comparison theorems for eigenvalues of perturbed Schrodinger operators that allow proof of Lieb--Thirring bounds for suitable non-free Schrodinger operators and Jacobi matrices.Comment: 11 page

    Astonishing 35S rDNA diversity in the gymnosperm species Cycas revoluta Thunb

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    17 p., tablas, gráficos.In all eukaryotes, the highly repeated 35S ribosomal DNA (rDNA) sequences encoding 18S-5.8S-26S ribosomal RNA (rRNA) typically show high levels of intragenomic uniformity due to homogenisation processes, leading to concerted evolution of 35S rDNA repeats. Here, we compared 35S rDNA divergence in several seed plants using next generation sequencing and a range of molecular and cytogenetic approaches. Most species showed similar 35S rDNA homogeneity indicating concerted evolution. However, Cycas revoluta exhibits an extraordinary diversity of rDNA repeats (nucleotide sequence divergence of different copies averaging 12 %), influencing both the coding and non-coding rDNA regions nearly equally. In contrast, its rRNA transcriptome was highly homogeneous suggesting that only a minority of genes ( T substitutions located in symmetrical CG and CHG contexts which were also highly methylated. Both functional genes and pseudogenes appear to cluster on chromosomes. The extraordinary high levels of 35S rDNA diversity in C. revoluta, and probably other species of cycads, indicate that the frequency of repeat homogenisation has been much lower in this lineage, compared with all other land plant lineages studied. This has led to the accumulation of methylation-driven mutations and pseudogenisation. Potentially, the reduced homology between paralogs prevented their elimination by homologous recombination, resulting in long-term retention of rDNA pseudogenes in the genome.The work was supported by the Czech Science Foundation (P501/13/10057S and P501/12/G090) and NERC (UK).Peer reviewe

    Angiosperms Are Unique among Land Plant Lineages in the Occurrence of Key Genes in the RNA-Directed DNA Methylation (RdDM) Pathway

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    We are grateful for the FP7 Marie Curie IEF (Lu Ma), the FP7 Marie Curie ITN INTERCROSSING (Andrea Hatlen), the Czech Science Foundation (501/12/G090, Ales Kovarik), China Scholarship Council (Wencai Wang), and NERC (NE/ G01724/1, Laura Kelly, Ilia Leitch, Andrew Leitch). The Illumina sequencing of Fritillaria was funded by NERC (NE/G01724/1) and generated by the Centre of Genomic Research in the University of Liverpool, UK. This research utilised Queen Mary's MidPlus computational facilities, supported by QMUL Research-IT and funded by EPSRC grant EP/K000128/1. We thank an anonymous referee for a rigorous, insightful and helpful revie
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