Stan Lee, co-founder of the Marvel Universe(漫威宇宙) and co-creator of many of its most popular superheroes, died at the age of 95.

Lee was born Stanley Martin Lieber in New York in 1992.  As a son of working-class Jewish immigrants from Romania, times were hard and he lived with his family in a shabby single-bedroom apartment. After graduating from high school at 16, Lieber landed a job as an assistant at Timely Comics. By the early 1940s, he was a temporary editor for the company. It was at this time that he began using his pen name--Stan Lee. In 1947, two years after returning from serving for the U.S. Army, Lee married his wife, Joan. The two began their 70-year marriage and had two children.

In the late 1950s, DC Comics breathed new life into its classic superhero and experienced a significant success with its updated version of the Flash, and later with super-team the Justice League(正义联盟) of America.

To compete against DC Comics, Lee was given the task of creating their own group of superheroes. In 1961, Timely Comics changed its name into Marvel Comics after Atlas Comics, and that November saw the debut(首次亮相) of the Fantastic Four. Lee's later famous and lasting creations of comic-book superheroes included Spider-Man, the Hulk, Thor, Iron Man and the X-men.

Over the course of his career, Lee was an icon of Marvel Comics. As a writer and editor and, at various points, both the publisher and vice president of Marvel Comics, Lee not only introduced interesting characters to the industry, but changed the way that comic books came together. He also created a cooperative workflow between writers and artists, which became known as the "Marvel Method". Lee received a National Medal of Arts in 2008 for his innovations that revolutionized (=completely changed) American comic books.

Thunderstorms often show up uninvited to Carnival (狂欢节) in Brazil. This year's attempt to influence the skies took place in Sao Pablo by a party's official sponsor, Skoal, a Brazilian beer brand. "The fun stops when it rains," says Pedro Ada my, Skoal's marketing director. So do beer sales.

An airplane painted with Skoal's logo sprayed (喷洒) water droplets into clouds to make rain fall before the clouds reached the city. According to its YouTube video that has been viewed 12 million times, it is a "mission worthy of science fiction".

Whether it's science or fiction is up for debate. The use of cloud-seeding to increase rainfall dates back to the 1940s. But the United States government stopped funding it in the 1980s due to a lack of" scientific proof of the effectiveness of intentional weather change", according to the National Research Council. A new paper based on experiments in Idaho found that seeding clouds with silver iodide increased snowfall on three occasions, but the authors say that more research is needed to find out if it can reliably promote precipitation (降水), Pablo Tartar, a Brazilian physicist, says flatly that cloud-seeding is "useless".

Still, governments and firms in many countries use the technology. Sao Pablo's water company has signed million dollar contracts with ModClima to bring rain, most recently during a drought in 2014-15. Although cloud-seeding normally uses a chemical such as silver iodide to provide a surface around which water or ice droplets form, ModClima says it has invented an "experimental" method that uses water alone.

Carnival-goers cheered when the first two days were cloudy but dry. Many shared Skol's video. But at around 5pm on February 24th, the sky darkened and rain poured down. Celebrants at one block party left the Skol stands and rushed to buy umbrellas and plastic rain capes.

To study the behavior of wild animals, scientists routinely tag them with GPS location trackers. But such devices' battery capacity limits how long they operate, often bringing an early end to significant conservation work. Solar-powered trackers are also a poor choice for they break easily and don't work for night creatures.

So biologist Rasmus W. H. of the University of Copenhagen and his colleagues turned to another abundant power source. After some trial and error, they finally came up with a tiny generator powered by a pendulum (摆锤) inside a closed device. As the tagged animal moves, the swinging pendulum forces a ring to slide across a copper coil, generating current which is then used to power the sensors for GPS unit. The tracker, which could theoretically survive for the entire life span of an active animal, was recently tested on domestic dogs, a wild pony and a European bison. The dogs and bison in the study were active enough to create the energy for one GPS transmission cycle per day for 14 days and 17 days, respectively. One of the wild pony's-trackers lasted at least 146 days but didn't produce enough power for daily transmissions, the researchers reported in Plos One.

The limited power generated by the animals' movements means the new tracker isn't ready for prime time just yet, says ecologist Emily Studd of British Columbia's Thompson Rivers University, who wasn't involved in the study. When researchers want to keep close track of animals, they often need GPS fixes more than once a day. But Studd says that with a bit more development, this could be a game changer for wild-life animal research and monitoring.

Rasmus and his colleagues hope conservation workers can one day use this technology to track species such as tigers, leopards and wolves, which can easily destroy solar-powered trackers and which hunt and travel at night.