A new eye-catching featured picture: Kelvin–Helmholtz instability can result from the turbulent mixing of two fluids of different density. It is sometimes observed in cloud formations, on the surface of gas giants such as Saturn, and when wind blows over a water surface. A mathematically generated GIF animation was converted to a video to be much more friendly to slow internet connections at virtually the same quality.
GorillaWarfare (nom), formerly Theunicyclegirl, who has been with us since July 2006. She is an active vandal-fighter, contributes to AfDs, and helps with the backlog of unreferenced articles.
Nev1 (nom), a prolific content contributor in areas related to Greater Manchester. This was Nev1's second successful RfA; he passed his first in 2008, but voluntarily gave up the tools in January 2010. Nev1 could have been re-promoted without going through an RfA, but believed "it would not be honest to claim an extant mandate from two years ago".
Jmh649 (nom), a Canadian emergency physician. "Doc James" (his signed name) has been active since July 2008, and a substantial contributor to important medical articles; these include obesity, gout, and streptococcal pharyngitis (commonly known as strep throat).
National Anthem of Russia (nom), adopted in December 2000. Alexander Alexandrov wrote the music, and Sergey Mikhalkov the lyrics (the melody had been used for the Soviet anthem) (Zscout370).
Stephens City, Virginia (nom), with a population of 1,500, was just south of the boundary between union and confederate states and was adjacent to a major free black community before the Civil War. It narrowly escaped torching by Union forces during the Civil War. (Neutralhomer)
Silky Sifaka (nom), a large, critically endangered lemur characterized by long, silky white fur. The male uses its specialized toothcomb to gouge trees before scent-marking with its chest. The article includes six sound files exemplifying this primate's extraordinarily varied auditory displays. (Simponafotsy and Visionholder, with taxonomic assistance from Ucucha). (sound file above)
"Road to the Multiverse" (nom), an episode of the animated television comedy series Family Guy, in which the main characters use a remote control device to travel through a series of various parallel universes (GageSkidmore).
Whitechapel murders (nom), the ghastly murders of eleven women—mostly prostitutes—in the 19th century. Although the true killer has yet to be revealed, the murderer is widely thought to be the "notorious, but elusive, individual known as Jack the Ripper" (DrKiernan).
90377 Sedna (nom), an astronomical object, about two-thirds the size of Pluto, which currently lies about three times as far from the Sun as the outermost planet, Neptune, and takes about 12,000 years to orbit the Sun (Kheider and Serendipodous).
Mark Tonelli (nom), an Australian Olympic swimmer of the 1970s and 1980s. He successfully lobbied for the right of Australian Olympians to compete in the 1980 Moscow Olympics despite the government's wish to boycott it to protest against the Soviet invasion of Afghanistan; he was stripped of the captaincy of the national team for poor behaviour (YellowMonkey).
Charles Domery (nom), another of Iridescent's "eating disorders of the French Revolutionary Wars" mini-series, in which a Polish soldier was captured by the British and subjected to a bizarre dietary experiment.
Choice of the week.The Signpost asked FA nominator and reviewer Iridescent to select his best of the week (and of course to dutifully disregard his own nomination). "I chose Silky Sifaka. To me, Wikipedia's great strength is its ability to treat relatively obscure topics with the same thoroughness it gives to the major topics. Readers can find equally good articles on major subjects elsewhere; but there's probably no other free resource which covers this particular species so thoroughly. With its combination of well-written prose neither over-technical nor dumbed-down, thoughtfully chosen images, and informative sound and video clips, this article is Wikipedia at its best." (sound-bite at the top)
Choice of the week. We asked FL nominator and reviewer Chrishomingtang, who specializes in basketball-related topics, for his choice: "I picked List of Watford F.C. seasons as my favorite. The lead flows well and clearly explains the team's history. The table looks great and every abbreviation is explained in the key section. The entire list is well-referenced and well-illustrated by relevant images."
A cast of the cranium of "Tournai", a member of an extinct hominid species who lived about 7 million years ago
Ford Focus RS WRC 09 (nom), an action shot of Jari-Matti Latvala driving his Ford Focus RS WRC 09 in Muurame shakedown. Photographer Kallerna, who achieved sharp focus despite the proximity and motion of the vehicle, assures us that "there was still room between me and the car (~ 1 metre)."
Kelvin–Helmholtz Instability (nom). This mesmerizing animation illustrates a Kelvin–Helmholtz instability arising at an interface between fluids of different densities and speeds (created by Bdubb12). (animated video at the top)
Choice of the week. We asked Makeemlighter, a regular reviewer and closer at featured pictures candidates, to choose his favorite among the past week's promotions: "With several outstanding images this week, it was a difficult choice. I kept coming back to the Freiburg panorama, so I'll make it my pick. This panorama is very sharp and well-stitched. As an American living in a suburban neighborhood, it's fascinating to see such a detailed image of this German city. I really get a great sense of what it must be like to live in Freiburg. It's particularly interesting to see the modern layout of a city that's been around since the 12th century. Be sure to check it out using the 360° viewer. " (below)
Featured picture Choice of the week: a panoramic view of Freiburg, Germany as seen from Schlossberg. Freiburg Münster (cathedral) can be seen in the center.