Goebbels, Heiner, author

Duetting as a collective behavior Logue, David M.; Krupp, Daniel B. Mated birds of many species vocalize together, producing duets. Duetting behavior occurs at two levels of organization: the individual level and the pair level. Individuals initiate vocalizations, answer their mates’ vocalizations, and control the structure and timing of their own vocalizations. Pairs produce duets that vary with respect to duration, temporal coordination, and phrase-type combinations, among other properties. To make sense of this hierarchical structure, organize duetting research, and identify new avenues of investigation, we advocate a “collective behavior” approach to the study of duets. We critically review key terminology in the duetting literature in light of this approach, and elucidate six insights that emerge from the collective behavior approach: (1) Individual-level behaviors describe pair-level behaviors, but the opposite is not true; (2) The level of organization informs how we test for the rules that govern behavior; (3) Functional hypotheses about duetting must distinguish individual from group characters; (4) Stimulus-response, cybernetics, and entrainment offer alternative hypotheses for the cognitive control of duetting behavior; (5) Avian duetting has the potential to be a model system for the ontogeny of vocal interaction; and (6) The collective behavior approach suggests new avenues of research. Ultimately, we argue that nearly every aspect of duetting research stands to benefit from adopting a collective behavior approach. This approach also has applications to other forms of interactive vocal communication in birds and primates, including humans. Sherpa Romeo green journal. Open access article. Creative Commons Attribution License (CC BY) applies.

My session driver of choice for CodeIgniter is database. A while ago, I noticed millions of rows in the corresponding database table. That means that garbage collector was not working. I checked config.php for sess_regenerate_destroy, but it was already set to false. It was really weird because the problem seemed to have come out of nowhere – not much ago things were working just fine.

After a short investigation, I found out this was and still is a common problem for those who had upgraded their CodeIgniter version from 2.x to 3.x. Turns out, the later possesses heavy changes for Sessions library. And most importantly – fundamental changes in dealing with garbage: CodeIgniter 3.x relies on PHP's native grabage collector. So, in order to get things working again, we need to configure PHP properly.

The Solution

Today there are three PHP-native settings for dealing with session garbage collector. CodeIgniter's Session library has already taken care of one of them – gc_maxlifetime – so there's no need for an extra touch here. The problem lies within the rest: session.gc_probability and/or session.gc_divisor. These two determine when the garbage collector is running. Here's what php.net says:

session.gc_divisor coupled with session.gc_probability defines the probability that the gc (garbage collection) process is started on every session initialization. The probability is calculated by using gc_probability/gc_divisor, e.g. 1/100 means there is a 1% chance that the GC process starts on each request.

In my case, using ini_get() revealed the following values: 0 and 1000. The equation 0/1000=0 meant there was no chance the garbage collector would even run.

Finally, I solved the problem by using the values officially stated as default and by putting the following lines of PHP code into config/config.php file:

ini_set( 'session.gc_probability',	1 );
ini_set( 'session.gc_divisor',		100 );

Theoretically, this means that the garbage collector usually runs once every 100th request. It's more than enough, but it is up to you whether that causes too many unnecessary hits to database. An alternative solution for heavy-traffic websites could be having a 0% probability on the production site and a Cronjob-based script which removes database rows of the expired sessions.

Online Resource

For the second time this year, Delhi government has allegedly released inadequate funds for the salaries of teaching and non-teaching staff of 12 Delhi University colleges, that too after a month-long delay.

The detection of Gravitational-wave in a collision between two black holes of substantially different masses has made astronomers excited.

Barker Library - TA444.L44 2014

Barker Library - TA439.J36 2016

Online Resource

Online Resource

New Brunswick : Rutgers University Press, [2019]

Edmonton, Alberta : Brush Education Inc., 2020

"It's kind of an island; it's own cultural island." In this Chicago minute, we explore the third largest city in the country and it's impact on the arts.

The National Museum of Play in Rochester, N.Y. recently acquired one of the largest collections of Japanese and European video games. From Mother to Zool to Doshin the Giant, Game|Life editor Chris Kohler gets the first look at the incredible rarities.

Sarah Stein Greenberg at WIRED by Design, 2014. In partnership with Skywalker Sound, Marin County, CA. To learn more visit: live.wired.com

Commune at WIRED by Design, 2014. In partnership with Skywalker Sound, Marin County, CA. To learn more visit: live.wired.com

Some would call David Rumsey a cartophile, while others may put it more bluntly and say he’s obsessed. Over 30 years he’s personally accumulated over 150,000 maps and he's just donated them all to Stanford University.

Lo: move a little clockwise Lo-High: move further clockwise High-Lo-High (fast): move a little counter-clockwise High-Lo-High (slow): move further counter-clockwise High: hold that line, slow down Two mid notes: walk on to the sheep High falling: lie down

WIRED editor-in-chief Nicholas Thompson spoke with Patrick Collison, CEO of Stripe about the future of work at WIRED's 25th anniversary celebration in San Francisco.

In this episode of Obsessed we meet Michael Schiess, a pinball enthusiast who collects and repairs old machines in an effort to preserve them for future generations.

Tolkien stars Lily Collins and Nicholas Hoult take the WIRED Autocomplete Interview and answer the internet's most searched questions about themselves. How do you get Lily Collins' eyebrows? Is Nicholas Hoult related to Tom Cruise? Where was Lily Collins raised? Tolkien is in theaters May 10

A team from the University of Southern California's Rocket Propulsion Laboratory became the first student team to launch a rocket into space. WIRED's Arielle Pardes spoke with Neil Tewksbury, the team's Lead Operations Officer, about what it took to make it happen. Read more of the team's story on WIRED.com: https://www.wired.com/story/a-rocket-built-by-students-reached-space-for-the-first-time/

Artist Alexa Meade paints on people to make them look like paintings of people. She's developed a style that flattens 3 dimensional objects into what at first appears to be a 2D image. See more at https://alexameade.com

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Chaudhuri, A. K., author

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Walecka, John Dirk, 1932- author

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