Sildenafil (viagra) is used to treat erectile dysfunction and is safe, with known side effects, but a few people have experienced light sensitivity and color vision impairment at the highest recommended dose.

That doesn't mean men who need it should stop taking it, the psychological consequences of erectile dysfunction are of more concern than side effects, which can include headache and blurred vision that disappear quickly. These occur because sildenafil was originally developed as a treatment for high blood pressure, and it also dilates blood vessels and relaxes smooth muscle in the penis, making it easier to achieve and maintain an erection. 

A recent study identified the coronavirus responsible for the pneumonia epidemic in the Hubei province of China and finds the bat-origin virus is related to other known pathogenic coronaviruses.

The 2019 coronavirus (CoV) causes fatal pneumonia that has claimed over 1,300 lives, with more than 52,000 confirmed cases of infection by mid-February, along with various impacts to the lives of the scholars who revealed the virus against the wishes of the Chinese government. 

We know the left and right side of our brain are specialized for cognitive abilities like language (left hemisphere) and the right hand. That functional lateralization is reflected by morphological asymmetry too. The left and right hemispheres differ subtly in brain anatomy, distribution of nerve cells, connectivity and even neurochemistry.

It can be seen on endocasts. Most humans have a combination of a more projecting left occipital lobe (located in the back of the brain) with a more projecting right frontal lobe.

Despite what you've heard, birds of a feather often don't flock together. In the real world, multiple bird species are often flying and feeding together. In the Amazon, 50 species may travel as a unit.

But are birds in these mixed flocks cooperating with one another or competing?

A new study suggests both. Just like a K-pop band such as BTS, Blackpink, or Red Velvet.

In a world of New York Times best-selling diet books and epidemiological claims about food and chemicals - even that if your mother used cosmetics it may have made you fat - it can be difficult for the public to know what to trust.

It won't be intermittent fasting, juice cleanses, or 10,000 steps, it will always be the calories. Energy balance matters, no matter how many times Center for Science in the Public Interest claims it's conspiracy to claim calories are why we gain weight.

After the 2020 census, it is expected that California will lose a seat in Congress and Texas will gain it. Texans tout greater personal freedom and lower taxes but a new study says it may be water.

California is mostly desert and gets the bulk of its water from other states. After another drought a few years ago the pubic demanded new water infrastructure, noting that California hasn't undertaken a major program since the 1960s while the population is over 100 percent greater. Housing costs are high because new construction can't take place without a water contract, forcing people to stay in coastal cities.