683 research outputs found

    Noncommutative Particles in Curved Spaces

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    We present a formulation in a curved background of noncommutative mechanics, where the object of noncommutativity θμν\theta^{\mu\nu} is considered as an independent quantity having a canonical conjugate momentum. We introduced a noncommutative first-order action in D=10 curved spacetime and the covariant equations of motions were computed. This model, invariant under diffeomorphism, generalizes recent relativistic results.Comment: 1+15 pages. Latex. New comments and results adde

    GASTRIC CARCINOMA WITH OSSEOUS METAPLASIA IN A DOG

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    This report describes an unprecedented case of a gastric carcinoma with osseous metaplasia in a 8-year-old male standard poodle. An exploratory laparotomy revealed a firm yellowish nodular mass in the pyloric region. The lesion was surgically removed and submitted for current histological examination. Immunohistochemistry was performed employing monoclonal antibodies for pan-cytokeratin, vimentin, smooth muscular a-actin and BMP-2/4. The mass consisted in neoplastic proliferation of epithelial cells, arranged in a tubular or acinar pattern and supported by scirrhous stroma, with mucin production and multiple foci of heterotopic ossification. Neoplastic epithelial cells showed strong positive immunostaining for AE1/AE3 and BMP-2/4, although they were negative for both vimentin and a-actin. Histopathological findings suggested that the bone tissue may be primarily originated from neoplastic epithelial cells which directly circumscribe the osseous metaplasia foci
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