208 research outputs found

    Bethe Ansatz solutions for Temperley-Lieb Quantum Spin Chains

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    We solve the spectrum of quantum spin chains based on representations of the Temperley-Lieb algebra associated with the quantum groups Uq(Xn){\cal U}% _{q}(X_{n}) for Xn=A1,X_{n}=A_{1}, Bn,B_{n}, CnC_{n} and DnD_{n}. The tool is a modified version of the coordinate Bethe Ansatz through a suitable choice of the Bethe states which give to all models the same status relative to their diagonalization. All these models have equivalent spectra up to degeneracies and the spectra of the lower dimensional representations are contained in the higher-dimensional ones. Periodic boundary conditions, free boundary conditions and closed non-local boundary conditions are considered. Periodic boundary conditions, unlike free boundary conditions, break quantum group invariance. For closed non-local cases the models are quantum group invariant as well as periodic in a certain sense.Comment: 28 pages, plain LaTex, no figures, to appear in Int. J. Mod. Phys.

    Die Bedeutung von Rhamnolipiden in der Pathogenese epithelialer Pseudomonas aeruginosa Infektionen

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    Pseudomonas aeruginosa (P. aeruginosa) ist ein ubiquitär vorkommendes, gramnegatives, monotrich begeißeltes, aerob lebendes Stäbchenbakterium. Das opportunistisches Pathogen befällt Menschen, Tiere, Insekten, Nematoden und Pflanzen und ist unter anderem aufgrund seiner Toleranz gegenüber einer Vielzahl von Desinfektionsmitteln und Antibiotika einer der wichtigsten Verursacher von nosokomialen Infektionen. Die Ergebnisse dieser Arbeit geben einen Hinweis darauf, dass P. aeruginosa das angeborene Immunsystem mit Hilfe von Rhamnolipid, einem vom Bakterium selbst produzierten Surfactant, umgeht. In der vorliegenden Arbeit konnte nachgewiesen werden, dass die Flagellin-induzierte hBD2-Expression in humanen Keratinozyten durch bakterielle Überstände von P. aeruginosa, die in der stationären Phase generiert wurden, supprimiert wird. Der supprimierende Faktor konnte in Versuchen als hitzestabil und durch Säure ausfällbar identifiziert werden. Außerdem blieb er bei Behandlung mit Proteinase K unbeeinflusst, es handelt sich deshalb nicht um ein Protein. Weitere Untersuchungen konnten den Faktor als Rhamnolipid identifizieren. Eine Kostimulation von Keratinozyten mit aufgereinigtem Rhamnolipid in Mengen unterhalb der zytotoxischen Konzentration zusammen mit Flagellin zeigte ebenfalls eine Supprimierung der induzierten hBD2-Expression. Ähnliche Effekte konnten bei Kostimulation der Keratinozyten mit Flagellin und BAPTA-AM, einem intrazellulären Calciumchelator, erreicht werden. Neben Flagellin als Induktor ließ sich auch die PMA-induzierte hBD2-Expression supprimieren. Dies lässt vermuten, dass Rhamnolipide mit Calcium-abhängigen Signalkaskaden, wie der PKC-Signalkaskade, interferieren. Die Versuche dieser Arbeit zeigen damit einen Weg, über den es P. aeruginosa möglich ist, sich auf der Haut zu etablieren, ohne seinen Hauptpathogenitätsfaktor, das Flagellin, verstecken zu müssen

    Type 1 diabetes, diabetic nephropathy, and pregnancy: a systematic review and meta-study

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    BACKGROUND: In the last decade, significant improvements have been achieved in maternal-fetal and diabetic care which make pregnancy possible in an increasing number of type 1 diabetic women with end-organ damage. Optimal counseling is important to make the advancements available to the relevant patients and to ensure the safety of mother and child. A systematic review will help to provide a survey of the available methods and to promote optimal counseling. OBJECTIVES: To review the literature on diabetic nephropathy and pregnancy in type 1 diabetes. METHODS: Medline, Embase, and the Cochrane Library were scanned in November 2012 (MESH, Emtree, and free terms on pregnancy and diabetic nephropathy). Studies were selected that report on pregnancy outcomes in type 1 diabetic patients with diabetic nephropathy in 1980-2012 (i.e. since the detection of microalbuminuria). Case reports with less than 5 cases and reports on kidney grafts were excluded. Paper selection and data extraction were performed in duplicate and matched for consistency. As the relevant reports were highly heterogeneous, we decided to perform a narrative review, with discussions oriented towards the period of publication. RESULTS: Of the 1058 references considered, 34 fulfilled the selection criteria, and one was added from reference lists. The number of cases considered in the reports, which generally involved single-center studies, ranged from 5 to 311. The following issues were significant: (i) the evidence is scattered over many reports of differing format and involving small series (only 2 included over 100 patients), (ii) definitions are non-homogeneous, (iii) risks for pregnancy-related adverse events are increased (preterm delivery, caesarean section, perinatal death, and stillbirth) and do not substantially change over time, except for stillbirth (from over 10% to about 5%), (iv) the increase in risks with nephropathy progression needs confirmation in large homogeneous series, (v) the newly reported increase in malformations in diabetic nephropathy underlines the need for further studies. CONCLUSIONS: The heterogeneous evidence from studies on diabetic nephropathy in pregnancy emphasizes the need for further perspective studies on this issue

    Ecological importance of lepidopteran defoliators on eucalyptus plantations based in faunistic and natural enemy analyses

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    Abstract Areas planted with Eucalyptus urophylla S.T. Blake variety platyphylla F. Muell. (Myrtaceae) expand annually in most regions of Brazil. Many lepidopteran species defoliate this plant, but with damage varying per species. The objective of this study was to identify the pest status of lepidopteran defoliators based in the faunistic analysis of these insects and of their natural enemies on E. urophylla variety platyphylla plantations in a representative producing region of Brazil. Adult moths of lepidopterans and of their natural enemies were captured using a light trap, installed every two weeks, from September 2016 to August 2018. A total of 183, 10, three and 139 lepidopteran species was captured and classified as primary, secondary, without defined importance to eucalypt plants and non-identified with 1,419, seven, 465 and 876 individuals, respectively. Two primary pest species were constants, two accessories and six accidentals and all secondary ones were accidentals. Six primary pest species were common and dominant and four non-dominants. Faunistic indices indicated the main lepidopteran species that should be monitored in pest management programs. Seven hymenopteran species (65 individuals), three dipterans (49 individuals) and two hemipterans (four individuals) were the natural enemies collected using light traps. The monitoring of lepidopteran pests with light traps can contribute to the management and to reduce damage and control costs for these species, besides identifying natural enemies for biological control programs in Eucalyptus plantations

    Evidence for proton acceleration up to TeV energies based on VERITAS and Fermi-LAT observations of the Cas A SNR

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    We present a study of γ\gamma-ray emission from the core-collapse supernova remnant Cas~A in the energy range from 0.1GeV to 10TeV. We used 65 hours of VERITAS data to cover 200 GeV - 10 TeV, and 10.8 years of \textit{Fermi}-LAT data to cover 0.1-500 GeV. The spectral analysis of \textit{Fermi}-LAT data shows a significant spectral curvature around 1.3±0.4stat1.3 \pm 0.4_{stat} GeV that is consistent with the expected spectrum from pion decay. Above this energy, the joint spectrum from \textit{Fermi}-LAT and VERITAS deviates significantly from a simple power-law, and is best described by a power-law with spectral index of 2.17±0.02stat2.17\pm 0.02_{stat} with a cut-off energy of 2.3±0.5stat2.3 \pm 0.5_{stat} TeV. These results, along with radio, X-ray and γ\gamma-ray data, are interpreted in the context of leptonic and hadronic models. Assuming a one-zone model, we exclude a purely leptonic scenario and conclude that proton acceleration up to at least 6 TeV is required to explain the observed γ\gamma-ray spectrum. From modeling of the entire multi-wavelength spectrum, a minimum magnetic field inside the remnant of Bmin150μGB_{\mathrm{min}}\approx150\,\mathrm{\mu G} is deduced.Comment: 33 pages, 9 Figures, 6 Table
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