Adult Physical Activity Keeps Immune System Young

It is widely accepted that aging is accompanied by remodelling of the immune system including thymic atrophy and increased frequency of senescent T cells, leading to immune compromise. However, physical activity, which influences immunity but declines dramatically with age, is not considered in this literature. We assessed immune profiles in 125 adults (55–79 years) who had maintained a high level of physical activity (cycling) for much of their adult lives, 75 age-matched older adults and ...

 Political Detox - Why Political Discussions Become Disres...

For one week, political stories are off-topic. Please flag them. Please also flag political threads on non-political stories. For our part, we'll kill such stories and threads when we see them. Then we'll watch together to see what happens. Why? Political conflicts cause harm here. The values of Hacker News are intellectual curiosity and thoughtful conversation. Those things are lost when political emotions seize control. Our values are fragile—they're like plants that get forgotten, then ...

 Teaching as Natural Selection

Teaching is commonly associated with instruction, yet in evolution, immunology, and neuroscience, instructional theories are largely defunct. We propose a co-immunity theory of teaching, where attempts by a teacher to alter student neuronal structure to accommodate cultural ideas and practices is sort of a reverse to the function of the immune system, which exists to preserve the physical self, while teaching episodes are designed to alter the mental self. This is a theory of teaching that ...

 Instruction vs. Selection

The main difference between an instructional system and a selectional system is that the instructional system uses information from the environment to change the properties of the object in question, but a selectional system has a large and varied population of objects, and the ones that are most fit for the environment are differentially reproduced. Hopefully an example Edelman uses from immunology will help clear this up. The theory prevailing before the present one was called the theory ...