196,252 research outputs found
Polycystic Kidney-like Disease in a Red-ear Slider Turtle (Trachemys scripta elegans)
No full textA 14-year-old red-ear slider turtle (Trachemys scripta elegans) with no history of pre-existing clinical disease died and was referred for necropsy examination. Grossly, oesophageal prolapse, bilateral renal cysts and a paraduodenal cystic mass were detected. Tissues were processed routinely for histology and immunohistochemistry (IHC) with primary antibodies specific for Wilm's tumour suppressor gene-1 (WT-1), insulin, glucagon and pancytokeratins. Microscopically, renal medullary cysts and medullary atrophy resembled the changes associated with polycystic kidney disease (PKD). The cysts of the paraduodenal mass were lined by ciliated epithelial cells resembling embryonal cells and were intensely positive for glucagon and insulin by IHC. There was no cytokeratin expression in either lesion. WT-1 expression in the paraduodenal mass was cytoplasmic and appeared non-specific. Lesions were consistent with renal PKD-like disease and a pancreatic cystic hamartoma
Trends in models and algorithms for fleet management
No full textFleet management represents a relevant activity at tactical and operational levels to be faced by private companies and public agencies devoted to passengers and freight transportation. Mathematical models and computation techniques have been developed for optimising and simulating the operation of transport fleets in order to serve the customers demand with the objective of cost efficiency. Many fleet management problems correspond to combinatorial optimization problems, such as vehicle routing and scheduling, that are notoriously difficult to solve, even in a static context. Moreover, dynamic fleet management concern real-time requirements of the provided service and the control of unforeseen events that could affect the performances of the transport operations. The aim of this paper is to identify the most relevant problems in fleet management relatively to different transport modes, each one with specific characteristics, and to present an overview of recent contributions both in the development of mathematical models and in the design of computation algorithms
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