9,886 research outputs found
Unclassified autoimmune pancreatitis mimicking pancreatic cancer
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
Synthesis and properties of Co-doped titanate nanotubes and their optical sensitization with methylene blue
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
Differential temporal beta‐diversity patterns of native and non‐native arthropod species in a fragmented native forest landscape
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
Agricultura irrigada X saúde ambiental: existe um conflito?
bitstream/CPAP/56455/1/ADM011.pdfFormato eletrônico
Nonlocal gravity and the diffusion equation
We propose a nonlocal scalar-tensor model of gravity with pseudodifferential
operators inspired by the effective action of p-adic string and string field
theory on flat spacetime. An infinite number of derivatives act both on the
metric and scalar field sector. The system is localized via the diffusion
equation approach and its cosmology is studied. We find several exact dynamical
solutions, also in the presence of a barotropic fluid, which are stationary in
the diffusion flow. In particular, and contrary to standard general relativity,
there exist solutions with exponential and power-law scale factor also in an
open universe, as well as solutions with sudden future singularities or a
bounce. Also, from the point of view of quantum field theory, spontaneous
symmetry breaking can be naturally realized in the class of actions we
consider.Comment: 18 pages, 5 figures. v2: typos corrected, references added. Major
changes are an expansion of the discussion of homogeneous perturbations and
the inclusion of cosmological fluids in the dynamic
Dynamical demixing of a binary mixture under sedimentation
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
Scaling Behavior of Driven Interfaces Above the Depinning Transition
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
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