8,017 research outputs found

    Unclassified autoimmune pancreatitis mimicking pancreatic cancer

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    A 24-year-old black male presented with a 1-week obstructive jaundice and intermittent abdominal pain, with no significant weight loss and an unsuspicious abdominal exam. Blood chemistry showed a cholestatic pattern but a complete immunological and tumoral panel (anti-smooth muscle antibody, anti-mitochondrial antibody, anti-nuclear antibody, anti-neutrophil cytoplasmic antibody, anti-Smith, anti-double-stranded-DNA antibody (anti-dsDNA), complement C3/C4, carcinoembryonic antigen, CA 19-9 and IgG4) were all within normal limits. Abdominal ultrasound revealed dilatation of the intra and extra-hepatic bile ducts. CT scan showed an abnormal dilatation of the distal bile duct but no focal enlargement of the head of the pancreas. Endoscopic ultrasound suggested an inflammatory process but the magnetic resonance cholangio-pancreatography favored a neoplastic obstruction of the distal common bile duct. Fine-needle aspiration cytology was insufficient for definitive diagnosis and the patient underwent major surgery. Follow-up with mild exocrine pancreatic insufficiency treated with enzyme replacement.info:eu-repo/semantics/publishedVersio

    Scaling Behavior of Driven Interfaces Above the Depinning Transition

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    We study the depinning transition for models representative of each of the two universality classes of interface roughening with quenched disorder. For one of the universality classes, the roughness exponent changes value at the transition, while the dynamical exponent remains unchanged. We also find that the prefactor of the width scales with the driving force. We propose several scaling relations connecting the values of the exponents on both sides of the transition, and discuss some experimental results in light of these findings.Comment: Revtex 3.0, 4 pages in PRL format + 5 figures (available at ftp://jhilad.bu.edu/pub/abbhhss/ma-figures.tar.Z ) submitted to Phys Rev Let

    Synthesis and properties of Co-doped titanate nanotubes and their optical sensitization with methylene blue

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    Here we report on a novel chemical route to synthesize homogenous cobalt doped titanate nanotubes (CoTNT), using an amorphous Co-doped precursor. The influence of the synthesis temperature, autoclave dwell time and metal doping on the structural and microstructural as well as on the optical properties of the synthesized titanate nanotubes is studied and discussed. The optical band gaps of the CoTNT samples are red shifted in comparison with the values determined for the undoped samples, such red shifts bringing the absorption edge of the CoTNT samples into the visible region. CoTNT materials also demonstrate particular high adsorption ability for methylene blue, the amount of the adsorbed dye being higher than the one predictable for a monolayer formation. This suggests the possibility of intercalation of the dye molecule between the TiO6 layers of the TNT structure. It is also shown that the methylene blue sensitized Co-doped nanostructures are highly stable under UV radiation and present a strong and broad absorption in the visible region.Comment: 31 pages, 3 tables, 7 figure

    Dynamical demixing of a binary mixture under sedimentation

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    We investigate the sedimentation dynamics of a binary mixture, the species of which differ by their Stokes coefficients but are identical otherwise. We analyze the sedimentation dynamics and the morphology of the final deposits using Brownian dynamics simulations for mixtures with a range of sedimentation velocities of both species. We found a threshold in the sedimentation velocities difference above which the species in the final deposit are segregated. The degree of segregation increases with the difference in the Stokes coefficients or the sedimentation velocities above the threshold. We propose a simple mean-field model that captures the main features of the simulated deposits

    Differential temporal beta‐diversity patterns of native and non‐native arthropod species in a fragmented native forest landscape

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    An important factor that hinders the management of non‐native species is a general lack of information regarding the biogeography of non‐natives, and, in particular, their rates of turnover. Here, we address this research gap by analysing differences in temporal beta‐diversity (using both pairwise and multiple‐time dissimilarity metrics) between native and non‐native species, using a novel time‐series dataset of arthropods sampled in native forest fragments in the Azores. We use a null model approach to determine whether temporal beta‐diversity was due to deterministic processes or stochastic colonisation and extinction events, and linear modelling selection to assess the factors driving variation in temporal beta‐diversity between plots. In accordance with our predictions, we found that the temporal beta‐diversity was much greater for non‐native species than for native species, and the null model analyses indicated that the turnover of non‐native species was due to stochastic events. No predictor variables were found to explain the turnover of native or non‐native species. We attribute the greater turnover of non‐native species to source‐sink processes and the close proximity of anthropogenic habitats to the fragmented native forest plots sampled in our study. Thus, our findings point to ways in which the study of turnover can be adapted for future applications in habitat island systems. The implications of this for biodiversity conservation and management are significant. The high rate of stochastic turnover of non‐native species indicates that attempts to simply reduce the populations of non‐native species in situ within native habitats may not be successful. A more efficient management strategy would be to interrupt source‐sink dynamics by improving the harsh boundaries between native and adjacent anthropogenic habitats.Portuguese FCT‐NETBIOME – ISLANDBIODIV grant 0003/2011.info:eu-repo/semantics/publishedVersio

    Reheating induced by competing decay modes

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    We address the problem of studying the decay of the inflaton field ϕ\phi to another scalar field χ\chi through parametric resonance in the case of a coupling that involves several decay modes. This amounts to the presence of extra harmonic terms in the perturbation of the χ\chi field dynamics. For the case of two frequencies we compute the geometry of the resonance regions, which is significantly altered due to the presence of non-cuspidal resonance regions associated to higher harmonics and to the emergence of instability `pockets'. We discuss the effect of this change in the efficiency of the energy transfer process for the simplest case of a coupling given by a combination of the two interaction terms of homogeneous degree usually considered in the literature. We find that the presence of higher harmonics has limited cosmological implications.Comment: 14 pages, 4 figures Added references. Corrected typo

    Meloboris insularis

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    JUSTIFICATION: Meloboris insularis is an endemic ichneumonid wasp species of the Azores (Portugal), having been recorded from Faial island. From the historical data, this species could have a very small Extent of Occurrence (16 km²) and Area of Occupancy (16 km²). Despite the location of its description being currently a Nature Reserve (Caldeira do Faial), it is possible that this species has declined in the past as a result of human activity. However, the present situation of this species needs to be further assessed, further research is needed into its population, distribution, threats, ecology, life history and indigenous host species. Conservation/restoration of native habitats, as well as invasive plant species control, could potentially also aid this species' conservation. Based upon the lack of recent data regarding this species population, distribution, threats, ecology and hosts, this species is assessed as Data Deficient (DD).info:eu-repo/semantics/publishedVersio

    Hidryta atlantica

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    JUSTIFICATION: Hidryta azorica is a potentially endemic species of the Azores (Portugal) known only from the holotype and for which there is no precise indication of island of occurrence, while it has been suggested that Hidryta atlantica might be a melanic form of H. sordida, a widespread European species. It possibly has a very small Extent of Occurrence (EOO = 4 km²) and Area of Occupancy (AOO = 4 km²). Based upon the unknown distribution and ecology, this species is assessed as Data Deficient (DD).info:eu-repo/semantics/publishedVersio

    Orthonychiurus azoricus

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    JUSTIFICATION: Orthonychiurus azoricus is an Azorean-endemic species described from S. Miguel island (Azores, Portugal) (Jacquemart, 1974), at an unknown location. Possibly it has a very small Extent of Occurrence (EOO = 4 km²) and Area of Occupancy (AOO = 4 km²); but the present situation of this species needs to be further assessed, and further research is needed into its population, distribution, threats, ecology and life history. Conservation of native habitats and streams could potentially aid this species' conservation. Based upon the lack of data regarding this species population, distribution, threats and ecology, this species is assessed as Data Deficient (DD).info:eu-repo/semantics/publishedVersio
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