Evaluation of the interferon-gamma (IFN-γ) assay to diagnose Mycobacterium bovis infection in pigs

Mycobacterium bovis recognizes as hosts a wide spectrum of animal species. In particular epidemiological situations, high prevalence of infection is found also in pigs. In the present study, we evaluated the capability of the interferon-gamma (IFN-γ) assay to identify pigs infected with M. bovis. The results of the immune-diagnosis were correlated to the findings of the post mortem inspection and the bacterial culture of lymph nodes. Blood samples of 146 pigs, belonging to a local breed of Sicily reared in free or semi-free roaming conditions, were collected to assess the specificity and the sensibility of the IFN-γ assay. Thirty-one pigs, from M. bovis free herds, did not react to the IFN-γ assay, yielding a specificity of 100%. The IFN-γ assay identified 15 out of 19 animals positive to the bacterial culture and 22 out of 26 animals with tuberculous lesions, with a sensibility of 78.9-84.6%, respectively. Out of 26 reactors to the test, 15 pigs (57.7%) confirmed to be infected after the bacterial culture and 22 (84.6%) had tuberculous lesions. The IFN-γ assay was able to reveal 4 animals with no visible lesions (NVL). Together, these findings support the feasible use of the IFN-γ assay as an intra vitam tool for the surveillance and management of M. bovis infection in swine populations.     

Radar detection of the nucleus and coma of comet hyakutake

Radar observations of comet Hyakutake (C/1996 B2) made at the Goldstone Deep Space Communications Complex in California have detected echoes from the nucleus and from large grains in the inner coma. The nucleus of this bright comet was estimated to be only 2 to 3 kilometers in diameter. Models of the coma echo indicate backscatter from porous, centimeter-size grains ejected anisotropically at velocities of tens of meters per second. The radar observations suggest that a comet's activity may be a poor indicator of its size and provide evidence that large grains constitute an important component of the mass loss from a typical active comet.     

Synchronous climate changes in antarctica and the north atlantic

Central Greenland ice cores provide evidence of abrupt changes in climate over the past 100,000 years. Many of these changes have also been identified in sedimentary and geochemical signatures in deep-sea sediment cores from the North Atlantic, confirming the link between millennial-scale climate variability and ocean thermohaline circulation. It is shown here that two of the most prominent North Atlantic events-the rapid warming that marks the end of the last glacial period and the Bolling/Allerod-Younger Dryas oscillation-are also recorded in an ice core from Taylor Dome, in the western Ross Sea sector of Antarctica. This result contrasts with evidence from ice cores in other regions of Antarctica, which show an asynchronous response between the Northern and Southern Hemispheres.