Astroviruses cause diarrheal disease in a number of different animal species (humans, pigs, sheep, turkeys) and hepatitis in ducklings. Astroviridae are a family of small (27-30 nm), round, unenveloped viruses with a characteristic star-shape on their capsid surface. Their genomes are single-stranded linear positive sense RNA of 6.8 to 7.9 kb. The genome encodes three open reading frames (ORF). ORFla encodes a serine protease; ORFlb, an RNA-dependent RNA polymerase; and ORF2, the viral capsid protein. There are currently eight known human astrovirus serotypes. All cause diarrheal disease predominantly in infants which is usually mild. Nosocomial outbreaks and outbreaks of infection in adults can occur.
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The use of dumbbells gives you a much more comprehensive strengthening effect because the workout engages your stabilizer muscles, in addition to the muscle you may be pin-pointing. Without all of the belts and artificial stabilizers of a machine, you also engage your core muscles, which are your body's natural stabilizers.