We can't even define dark matter, other than it being some blanket term for something that must exist due to unexplainable gravitational influence on the movements and appearance of stars or galaxies. 

Based on indirect evidence, astronomers believe that dark matter is the dominant type of matter in the Universe – everything else has been conjecture. But astronomers using high-energy observatories believe they may have discovered a clue that hints at this elusive invisible ingredient. 

Some studies have suggested a link between cannabis use and schizophrenia, but it has remained unclear whether this association is due to cannabis directly increasing the risk of the disorder. 

Cannabis is the most widely used illicit drug in the world, and its use is higher amongst people with schizophrenia than in the general population. Schizophrenia affects approximately 1 in 100 people and people who use cannabis are about twice as likely to develop the disorder. The most common symptoms of schizophrenia are delusions (false beliefs) and auditory hallucinations (hearing voices). The exact cause is unknown. A combination of physical, genetic, psychological and environmental factors can make people more likely to develop the disorder.

Smartphones are everywhere, and they may tell something about you that you didn't realize could be told.

When we touch things we give it our 'germs' and that knowledge could tell researchers something about our personal microbial world. Our phones can be biological and environmental sensors.

It was once the case that computer security for users was a non-issue. Most break-ins of networks involved someone local, not a brute force password discovery. Now, remote hackers in China are constantly hammering US sites using automated tools.

Password security involves a trade-off; complex is good but too complex and people will write it down, which is bad. A new alternative called  'Facelock' is based on the psychology of face recognition.

The Greenland Ice Sheet is huge, a 1.7 million-square-kilometer, 2-mile thick layer of ice that covers Greenland.

In the last 40 years, ice loss from the Greenland Ice Sheet has increased four-fold, contributing to global sea level rise. Some of the melting at the surface of the ice sheet is due to a warmer atmosphere but the ocean's role in driving ice loss largely has been a mystery.

A new paper in Nature Geoscience sheds new light on the connection between the ocean and Greenland's outlet glaciers, and provides important data for future estimates of how fast the ice sheet might melt and how much mass could be lost. 

 Lavado cocoa is primarily composed of polyphenols, antioxidants also found in fruits and vegetables. Some studies have suggested that they prevent degenerative diseases of the brain and a new study
in the Journal of Alzheimer's Disease found that a specific preparation of Lavado may reduce damage to nerve pathways seen in Alzheimer's disease patients' brains long before they develop symptoms.

The researchers used mice genetically engineered to mimic Alzheimer's disease and it was found that the Lavado cocoa extract prevents the protein β-amyloid- (Aβ) from gradually forming sticky clumps in the brain, which are known to damage nerve cells as Alzheimer's disease progresses.  

Writing about the weird soft-bodied fossils found in the Burgess Shale in the Canadian Rockies, paleontologist Stephen Jay Gould noted that of 25 initial body plans exhibited by the fossils, all but four were quickly eliminated.

If we rewound the tape, he asked, and cast the dice once more, would the same four body plans be selected? He thought it unlikely.

Obviously, we can't repeat the Burgess Shale, but Ken Olsen, an associate professor of biology at Washington University in St. Louis, says there are other ways to ask whether evolution is repeatable. One is to look at related species that have independently evolved the same traits and ask if the same genes are responsible and, if so, whether the same mutations led to the trait.

Policy makers may think more sin taxes will cut consumption - but it doesn't really work that way. Supermarkets recognize there are a lot more poor people than rich people and so they don't mark up the same products accordingly.

A paper written by the University of Sheffield with business experts from the University of East Anglia and Loughborough University discovered retailers appear to respond to increases in alcohol taxes by 'under-shifting' their cheaper products (raising prices below the level implied by the tax increase) and 'over-shifting' their more expensive products (raising prices beyond the level implied by the tax increase).  

The symptoms of Cushing disease are unmistakable to those who suffer from it – excessive weight gain, acne, distinct colored stretch marks on the abdomen, thighs and armpits, and a lump, or fat deposit, on the back of the neck. Yet the disorder often goes misdiagnosed.

Biologists have long wondered if mammals share the elegant system used by insects, bacteria and other invertebrates to defend against viral infection. Two back-to-back studies in the journal Science last year said the answer is yes, but a study just published in Cell Reports by researchers at the Icahn School of Medicine at Mount Sinai found the opposite.

In the Mount Sinai study, the results found that the defense system used by invertebrates — RNA interferences or RNAi — is not used by mammals as some had argued. RNAi are small molecules that attach to molecular scissors used by invertebrates to cut up invading viruses.