4 research outputs found
Automated Speckle Interferometry of Known Binaries
Astronomers have been measuring the separations and position angles between
the two components of binary stars since William Herschel began his
observations in 1781. In 1970, Anton Labeyrie pioneered a method, speckle
interferometry, that overcomes the usual resolution limits induced by
atmospheric turbulence by taking hundreds or thousands of short exposures and
reducing them in Fourier space. Our 2022 automation of speckle interferometry
allowed us to use a fully robotic 1.0-meter PlaneWave Instruments telescope,
located at the El Sauce Observatory in the Atacama Desert of Chile, to obtain
observations of many known binaries with established orbits. The long-term
objective of these observations is to establish the precision, accuracy, and
limitations of this telescope's automated speckle interferometry measurements.
This paper provides an early overview of the Known Binaries Project and provide
example results on a small-separation (0.27") binary, WDS 12274-2843 B 228
Enteric defensins are essential regulators of intestinal microbial ecology
Antimicrobial peptides are important effectors of innate immunity throughout the plant and animal kingdoms. In the mammalian small intestine, Paneth cell alpha-defensins are antimicrobial peptides that contribute to host defense against enteric pathogens. To determine if alpha-defensins also govern intestinal microbial ecology, we analyzed the intestinal microbiota of mice expressing a human alpha-defensin gene (DEFA5) and in mice lacking an enzyme required for the processing of mouse alpha-defensins. In these complementary models, we detected significant alpha-defensin-dependent changes in microbiota composition, but not in total bacterial numbers. Furthermore, DEFA5-expressing mice had striking losses of segmented filamentous bacteria and fewer interleukin 17 (IL-17)-producing lamina propria T cells. Our data ascribe a new homeostatic role to alpha-defensins in regulating the makeup of the commensal microbiota