Robinson, Jo (Professor), author

Krishnan, Sarasa, author

Hunter, Kelly, 1961- author

Eckersall, Peter, author

Cixous, Hélène, 1937- author

Shurtleff, Michael, author

Turner, Cathy, 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.

Chorus song of the indri (Indri indri: Primates, Lemuridae): Group differences and analysis of within-group vocal interactions Baker-Medard, Merrill S. A.; Baker, Myron C.; Logue, David M. The loud chorus songs of the group-living lemur Indri indri are a striking feature of rainforest areas of eastern Madagascar. Despite some research on the conspicuous vocal display of the indri, two hypotheses have not been addressed: do groups differ in the acoustic properties of their songs, and is there evidence of coordinated singing between individuals within groups. We recorded and analyzed the songs of three indri groups to examine these two questions. To answer the first question, we made quantitative spectral measures on songs of the three groups and performed multivariate analyses of the acoustic features of the notes constituting the songs. Our results showed songs of the three groups differed significantly, although there was overlap between groups. To answer the second question, we classified note types and quantified their occurrence as overlapping and abutting pairs. We found non-random associations between sequential note types in all three indri groups. These associations were consistent among groups, suggesting that individuals follow consistent answering rules when contributing to choruses. Whether indris use acoustic group identifiers in management of behavioral strategies and how within-group coordinated note production might function remain unknown. We compare our results to a number of taxonomically diverse species that live in groups and broadcast chorus and duet vocal signals. Open access article. Creative Commons Attribution 4.0 International License (CC BY 4.0) applies.

I only wrote a chapter in this new book, The HTML and CSS Workshop: A New, Interactive Approach to Learning HTML and CSS, but it is a new book and my name is on it and it’s on Amazon, so it’s still ???? cool. I wrote the chapter on Themes, Colors, and Polish. Here’s what […]

News flash! Both Mastering SVG and The HTML and CSS Workshop are available as eBooks for $5 starting today.

Like many of you I’m working from home for a while. As a mental health strategy, I’m going to do some writing and coding in the hour or so I get back each day from not having to commute. The first post, which will follow today, will be my thoughts on working from home. I […]

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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.

Service Worker has already been here for a while: since 2015-09 it has been fully supported in Chrome/Opera and if compared to what we have today it has gone a promising way of improvements, bug fixes, became more easily debuggable and is supported much widely (hello Firefox). That led us into using the technology in production and implementing it in our kollegorna.se website, as well as some client projects. We’ve learned there quite a few gotchas to grasp in order to get Service Worker working correctly…

Here is the list of what I overviewed in the article:

• Service Worker is a part of Progressive Web Apps
• What Service Worker is for
• Registering a Service Worker
• HTTPS and localhost
• Service Worker working scope
• ES6: to be or not to be?
• “Offline” page
• Service Worker lifecycle and events hierarchy
• Critical and non-critical resources
• Service Worker strategies
• Serving “offline” image
• Garbage in cache is your problem
• Service Worker and DOM
• Service Worker for multilingual website
• Service Worker is backend-dependent
• Debugging Service Worker

Read the article

Middleman is a Ruby based static site generator which we use heavily at Kollegorna both for prototyping (checkout our Middleman boilerplate) and production sites. In my previous article on Service Worker, I overviewed the most common challenges you may face when implementing the technology. This time I’d like to dive into a single specific topic of enabling a worker on Middleman based website as there are a few things to deal with…

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Or the priority navigation pattern, or progressively collapsing navigation menu. We can name it in at least three ways..

There are multiple UX solutions for tabs and menus and each of them have their own advantages over another, you just need to pick the best for the case you are trying to solve. At design and development agency Kollegorna we were debating on the most appropriate UX technique for tabs for our client’s website…

I wrote an article, coded a demo and got it all published on CSS-Tricks — you're very welcome to read, try and use it!

Read the article

Try the demo

Hayden Library - TA418.9.N35 N396 2012

Barker Library - TA418.9.N35 N68 2012

Barker Library - TK7874.85.B49 2013

Hayden Library - TA418.9.N35 I5737 2013

Hayden Library - TA418.9.N35 S54 2011

Barker Library - TK7874.85.N365 2012

Hayden Library - T174.7.P46 2012

Hayden Library - T174.7.C459 2011

Hayden Library - TP248.25.N35 Y68 2013

Hayden Library - T174.7.N79 2013

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Hayden Library - TA418.9.N35 S967 2012

Barker Library - QC176.8.N35 C43 2013