RESUMEN
Brown dwarfs are massive analogs of extrasolar giant planets and may host types of atmospheric circulation not seen in the solar system. We analyzed a long-term Spitzer Space Telescope infrared monitoring campaign of brown dwarfs to constrain cloud cover variations over a total of 192 rotations. The infrared brightness evolution is dominated by beat patterns caused by planetary-scale wave pairs and by a small number of bright spots. The beating waves have similar amplitudes but slightly different apparent periods because of differing velocities or directions. The power spectrum of intermediate-temperature brown dwarfs resembles that of Neptune, indicating the presence of zonal temperature and wind speed variations. Our findings explain three previously puzzling behaviors seen in brown dwarf brightness variations.
RESUMEN
A patient was recently seen with pseudomembranous colitis. He had severe disease of the proximal colon, with normal-appearing rectum and distal sigmoid, three weeks after administration of prophylactic antibiotics for surgery. The patient improved after discontinuing the antibiotics. Fiberoptic colonoscopy should be performed in patients suspected of having pseudomembranous colitis, even when sigmoidoscopy results are normal.
Asunto(s)
Antibacterianos/efectos adversos , Colon/patología , Enterocolitis Seudomembranosa/patología , Biopsia , Colon Sigmoide/patología , Colonoscopía , Diagnóstico Diferencial , Enterocolitis Seudomembranosa/inducido químicamente , Tecnología de Fibra Óptica , Humanos , Masculino , Persona de Mediana Edad , Recto/patologíaRESUMEN
A review of 147 autopsies performed over a 4.5-year period on patients with a diagnosis of primary carcinoma of the lung revealed that 18 (12%) had metastatic lesions in the gastrointestinal tract. Fourteen had a single focus of gastrointestinal involvement, while four had multiple lesions in the gastrointestinal tract. Large cell carcinoma accounted for a large percentage (33%), out of proportion to the general occurrence of this cell type (12%). Twelve of the 18 patients had signs or symptoms suggesting gastrointestinal involvement but only four were diagnosed premortem. Gastrointestinal involvement in metastatic carcinoma of the lung occurs more frequently than realized and is often overlooked.
