Decline and fall

AIDS: Decline and fall of immune surveillance?

Recent observations cast doubt on the view that cytotoxic T cells play a key role in keeping HIV-1 infection in check, and that it is the decline in this mechanism of immune surveillance that permits progression to AIDS.

Decline and Fall of Activity with Age

Ages for the components of binary stars are calculated from measurements of their chromospheric activity using the HK spectrophotometer at Mount Wil-son Observatory. Binaries are useful for age calibration because bright open clusters spanning the entire solar Main Sequence lifetime are not readily available, and also because age determinations using moving groups are comparatively uncertain ow...

'The decline and fall of hospital paediatrics' 23 years after.

The Decline and Fall of Type II Error Rates

Introductory statistics students learn that hypothesis tests in­ volve two types of error. If we reject a true null hypothesis, a Type I error occurs. If we fail to reject a false null hypothesis, a Type II error occurs. Students become adept at using tables to find critical values that control the probability of a Type I error. However, the calculations needed to control the probabil­ ity of a...

Social Evolution: The Decline and Fall of Genetic Kin Recognition

Animals should benefit from the ability to recognise their kin, yet curiously this faculty is often absent. New theory confirms that genetic kin recognition is inherently unstable, explaining its rarity.