The On-orbit Calibrations for the Fermi Large Area Telescope

The Large Area Telescope (LAT) on--board the Fermi Gamma ray Space Telescope began its on--orbit operations on June 23, 2008. Calibrations, defined in a generic sense, correspond to synchronization of trigger signals, optimization of delays for latching data, determination of detector thresholds, gains and responses, evaluation of the perimeter of the South Atlantic Anomaly (SAA), measurements of live time, of absolute time, and internal and spacecraft boresight alignments. Here we describe on orbit calibration results obtained using known astrophysical sources, galactic cosmic rays, and charge injection into the front-end electronics of each detector. Instrument response functions will be described in a separate publication. This paper demonstrates the stability of calibrations and describes minor changes observed since launch. These results have been used to calibrate the LAT datasets to be publicly released in August 2009.Comment: 60 pages, 34 figures, submitted to Astroparticle Physic

Pulmonary actinomycosis: a case undergoing resection through video-assisted thoracic surgery (VATS)

Actinomycosis is an uncommon disease, which is usually manifested as cervicofacial infection and related to poor oral hygiene or compromised immune function. Pulmonary actinomycosis is rare, but its diagnosis is changing due to its variable presentation and the similarity in appearance to other intrapulmonary diseases. Here we report an 80-year-old man with a solitary pulmonary nodule over the left upper lobe. Pulmonary neoplasm was highly suspected in this patient and thus resection of the mass was undertaken through video-assisted thoracic surgery (VATS). Histopathological examination demonstrated this patient had an Actinomyeces infection. While the application of VATS in patients with pulmonary actinomycosis has rarely been reported in literature, we conclude that VATS is valuable for the diagnosis and treatment of patients with undetermined pulmonary nodule(s)