The main active constituent of cannabis - tetrahydrocannabinol or THC - has not shown to be effective in slowing the course of progressive multiple sclerosis (MS).

The CUPID (Cannabinoid Use in Progressive Inflammatory brain Disease) study was carried out by researchers from Plymouth University Peninsula Schools of Medicine and Dentistry,the Medical Research Council Clinical Trials Unit and University College London and is the first large, non-commercial clinical study of THC for MS progression.

Of the estimated 20,000 genes humans have, only a fraction are turned on at any given time. It depends on the cell's needs, which can change by the minute or hour.

Determining what those genes are doing means using tools that can manipulate their status on similarly short timescales and that is now possible with technology developed by the Eli and Edythe L. Broad Institute of Harvard and MIT. It can rapidly start or halt the expression of any gene simply by shining light on the cells.

The advance in optogenetics, which uses proteins that change their function in response to light, is possible because researchers adapted light-sensitive proteins to either stimulate or suppress the expression of a specific target gene almost immediately after the light comes on.

Adineta vaga, the delloid rotifer, abandoned sex yet still produced more than 460 species over evolutionary time.

Rather than the standard way of using sexual reproduction to weed out harmful mutations to its DNA, this tiny aquatic animal appears to have adopted other strategies to maintain lineages over millennia that aren't burdened by genetic damage or killed off altogether.

Does buying a Snickers bar instead of a Milky Way improve a baseball team's chance to win?  You can't prove it doesn't - and for that reason the most superstitious baseball fans have little brand loyalty beyond their baseball team.

A paper in the Journal of Consumer Research by Gita V. Johar of Columbia Business School and Eric J. Hamerman of Tulane University shows a sports fan will easily switch to a different product if the fan believes the new brand will bring about good luck or eliminate bad luck. Routines are simultaneously that important and completely malleable, they say.

A family of molecules called TAML activators provide an environmentally friendly method for breaking down toxic compounds that contaminate water, including endocrine disruptors.

Shrinking sea ice cover in the North Atlantic - baby harp seals impacted most.

A new paper says satellite images have allowed researchers to gauge the relative roles that genetic, environmental and demographic factors such as age and gender may be playing in harp seal stranding rates along the U.S. and Canadian east coasts in recent years.  Recent warming in the North Atlantic gets the blame, according to the paper by advocacy group the International Fund for Animal Welfare and Duke University.