The chemical messenger dopamine, colloquially called the 'happiness hormone', is important outside social psychology articles on Valentine's Day also; it has been linked to motivation and motor skills and may help neurons with difficult cognitive tasks.  Researchers have found how dopamine influences brain cells while processing rules.

Skin color varies according to latitude and therefore by the intensity of incident ultraviolet light; according to biologists, that is why individuals living at low latitudes developed darker skin, whereas those living at high latitudes ended up with paler pigmentation. 

Yet the mutations that lightened the skin, probably owing to the need to synthesize vitamin D at latitudes with less solar irradiation, also increase the probability of developing melanoma or skin cancer, which is a negative in natural selection. 

A new article  in the Georgia Law Review
details the relationship of two U.S. Supreme Court cases, their impact on freedom of expression, and how they relate to blogging and citizen journalism.

Psychology surveys have found that when people go to bed and thus how long they sleep at a time might actually make it difficult for people to stop worrying.

The surveys showed that people who sleep for shorter periods of time and go to bed very late at night often have more negative thoughts than those who keep regular sleeping hours.  

Alzheimer's disease progresses inside the brain as deposits of the toxic protein amyloid-beta (Aβ),overwhelm neurons. A side effect of accumulating Aβ in neurons is the fragmentation of the Golgi apparatus, the part of the cell involved in packaging and sorting protein cargo including the precursor of Aβ. Or it may be the other way around and loss of Golgi function is a driving force behind Alzheimer's.

Yanzhuang Wang, Gunjan Joshi, and colleagues at the University of Michigan, Ann Arbor, set out to uncover the mechanism damaging the Golgi using a transgenic mouse and tissue culture models of 
Alzheimer's disease
to look at what was going on. 

Epidemiologists have examined the relationship between body weight and life expectancy and say that overweight and obese individuals have the potential to decrease life expectancy by up to 8 years.

If diabetes or cardiovascular disease develop, that could shorten life expectancy ever more, according to their analysis of data from the National Health and Nutrition Examination Survey (years 2003 to 2010) which was used to estimate the annual risk of diabetes and cardiovascular disease in adults with different body weights.

The data from almost 4,000 individuals was also used to analyze the contribution of excess body weight to years of life lost and healthy years of life lost.