American Medical Association (AMA) -

Physician Guide to Media Violence

10:44:44 PM    

City populations
10:37:38 PM    

Nature Insight- Ageing.

Why do we age?

Thomas B. L. Kirkwood* & Steven N. Austad

"Evolutionary history has determined that individuals thrive for long enough to

produce and nurture their offspring. Thereafter, the ageing process involves a

slow decline in physiological vigour and an increasing susceptibility to age-related

disease. Much of human culture and thinking has been shaped by the inevitability of

our ageing and death.

The current scientific picture of ageing presents us with an intriguing jigsaw puzzle.

We know, for example, that reducing food intake can slow the ageing process, at least

in lower animals such as nematode worms. We know that telomeres, which protect the

ends of chromosomes, erode as our cells age. But how can we connect together these

and other discoveries to give a meaningful picture of the genetic and biochemical

processes that underlie ageing? With this goal in mind we have assembled a collection

of review articles which rehearse our current understanding of the ageing process from

several distinct vantage points. ..."

4:07:22 PM    

HRT and risk of breast cancer death (Bandolier)

Clinical bottom line

The available evidence is that use of HRT is not associated with an increased risk of breast cancer.

Reference

K Nanda et al. Hormone replacement therapy and the risk of death from breast cancer: a meta-analysis. American Journal of Obstetrics and Gynecology 2002 186: 325-334.

3:23:59 PM    

Minding the baby, evolution and demographic transition

Schuyler Waynforth & David Waynforth

Abstract

Evolutionary theorists have struggled to make sense of the fertility reduction that

accompanies the demographic transition. This fertility reduction appears to be

evolutionarily maladaptive, especially since wealthy individuals in industrialized

economies could almost certainly have many more children than they do without

substantially compromising their children’s survival to adulthood. Attempts at

reconciliation with evolutionary theory have largely focused on wealth, and how

resources and modern economies may reduce the optimal number of children to produce,

or how we could have evolved in ways that would not yield the optimum under highly

novel industrialized contexts. Here, arguments based on evolutionary life-history theory

are applied to the comparatively ignored topic of direct, non-economic forms of parental

care and fertility. We compile evidence showing that more direct parental care, and

parenting from more caregivers associate with improved outcomes for children, including

survival and social functioning. This could have led to the evolution of mechanisms that

fit availability of direct parental care with fertility, to produce an optimal number and

quality of children. Modernization has reduced the number of available caregivers,

particularly biological kin, who are typically favored as babysitters. We propose that

humans have evolved to handle large, sudden decreases in the availability of direct care

for children by reducing fertility. Through this argument, we hope to reinvigorate interest

in direct forms of parental care and their potential role in fertility decisions.

 

2:59:33 PM