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November 30, 2012

Quorum sensing, rabid bats, birds, and pigs

Bacterial quorum sensing, cooperativity, and anticipation of stationary-phase stress "QS allows individuals to anticipate and survive stationary-phase stress."

Optimality and robustness in quorum sensing (QS)-mediated regulation of a costly public good enzyme "exoenzyme production is overall advantageous only if initiated at a sufficiently high density."

Variable evolutionary routes to host establishment across repeated rabies virus host shifts among bats "few sites exhibited repeated evolution across adaptation to many bat species, suggesting diverse genetic determinants over host range"

The genomic landscape of species divergence in Ficedula flycatchers "approximately 50 'divergence islands' showing up to 50-fold higher sequence divergence than the genomic background"

Strong signatures of selection in the domestic pig genome "strong signatures of selection at three loci harboring quantitative trait loci that explain a considerable part of one of the most characteristic morphological changes in the domestic pig--the elongation of the back and an increased number of vertebrae"

November 16, 2012

This week's picks

Radiocarbon dates from the Grotte du Renne and Saint-Césaire support a Neandertal origin for the Châtelperronian "production of body ornaments in the CP postdates the arrival of modern humans in neighboring regions of Europe. This new behavior could therefore have been the result of cultural diffusion from modern to Neandertal groups. "

Hornwort pyrenoids, carbon[dioxide]-concentrating structures, evolved and were lost at least five times during the last 100 million years "The nonsynchronous appearance of pyrenoid-containing clades, the successful diversification of pyrenoid-lacking clades during periods with low [CO2], and the maintenance of pyrenoids during episodes of high [CO2] all argue against the previously proposed relationship between pyrenoid origin and low [CO2]. "

Convergent Evolution Between Insect and Mammalian Audition "katydids and mammals, have evolved a series of convergent solutions to common biophysical problems"

Metazoan opsin evolution reveals a simple route to animal vision
"Placozoa have opsins"

Evolutionary biology: Birds of a feather

Spontaneous motion in hierarchically assembled active matter

Animal behaviour: Personality in the wild

Evidence for Early Hafted Hunting Technology

Allard's argument versus Baker's contention for the adaptive significance of selfing in a hermaphroditic fish

November 9, 2012


Will headshot.jpg
Will Ratcliff gives great talks. It helps that his results are so exciting, but here are some of his other secrets. He made a PDF version also: David Attenborough style of scientific speaking.pdf

One of the biggest hurdles to giving a good talk is convincing people that it's worth their mental energy to listen to you. This approach to speaking is designed to get that buy-in from the audience, without them even realizing they are doing so. The key to this is exploitation of a simple fact: people are curious creatures by natureand will pay attention to a cool story as long as that story remains absolutely clear.

In the D.A. style of speaking, you are the narrator of an interesting story. The goal is to have a visually streamlined talk where the audience is so engaged with your presentation that they forget you're standing in front of them speaking. Instead, they're listening to your narrative and seeing the visuals that accompany your story, at no point do they have to stop and try to make sense of what you just said.

Here are the key points:

1. Get into this mindset: your main job is to be an entertainer, not a scientist. Most scientists don't do this, which is why most scientific talks are bad. The fact of the matter is that if the audience doesn't understand and enjoy your talk, they won't care if your science is good.
2. Tell a story; don't simply talk about your methods and results.
3. A solid scientific narrative is critical for easy comprehension, and easy comprehension is critical for the D.A. style!The audience needs to understand every word you are saying, because once someone is no longer paying attention, the spell is broken. Your goal is to never lose someone's attention. Thus, a clear narrative arc is essential for success. See talk outline suggestions below.
4. Practice your transitions between slides and subjects.The most common place to lose people's attention is with a bad transition. Once someone is no longer following along with you, it's hard for them to get back into the flow of the talk.
5. Kill clutter. Remove text. Complete sentences are to be banished from your talk.Rather than write full sentences, speak them while pointing people's attention to visuals that reinforce your point.Exception:A single sentence (or sentence fragment)at the top of each slide that capture's that slide's main point is a good idea.
6. Only show as much of the slide as people need to understand the point you are making at that precise moment.I often hide most of the slide, revealing additional detail only once it is needed to understand my narrative. For this to be most effective, learn to use custom animations in Powerpoint.
7. Be excited. If you're not excited about your work, why should the audience be excited?
8. Be engaged.Do not speak to the ceiling, floor, or (worst yet) your presentation. They are not the audience. Keep your eyes toward the back of the lecture hall.It makes people feel like you're engaging with them, and also makes them feel watched.They will pay better attention this way.
9. Jokes are tricky, you probably have more to lose than to gain.While your job is to be an entertainer, this is still a scientific talk, so keep silliness to a minimum. A good joke can really rally people to your side, but the audience has to already have a positive disposition towards you for this to work. A poorly timed or executed joke can do a lot of damage, so keep jokes to a minimum unless you really know your audience.

Phase 1.Setting up the talk.This is probably the most important and difficult part of the talk to write, butthis section is critical for framing the narrative arc. The rest of the talk follows naturally from the intro. Keep it short and keep it direct.
a. Big picture context.Imagine David Attenborough talking about how cool Madagascar is while the screen shows aerial footage of a majestic mountain range. You want something big like this. I find it helpful to memorize the broad overview I give during my first slide.
b. Key questions you are investigating (zoom in from the big picture).Scientists love interesting questions even more than they love answers. You will set up a nice talk if you can ask questions in the beginning that you later answer.
c. Don't bury the lead. Get quickly to your main result in broad brush strokes, and then move on. People really don't like suspense, and they have bad memories. So tell them the main answer before going into the details. Rather than try to figure out where you're going, they'll be able to concentrate on the smaller details of your talk.
Phase 2.Methods and Results.
a. Keep methods brief.Most don't care about methods, it's a distraction from the story. Provide enough detail that they know what you did and have some confidence that you know what you are doing.
b. Answer the questions you raised earlier. Tell the story as clearly as possible, keeping in mind that you are answering the questions laid out in the intro.
Phase 3.Concluding the talk.
a. Briefly recap the answers to the questions laid out in the intro.
b. Provide context for why your results are important in the big picture.See the symmetry? We start with the big picture, and end with the big picture and how your results affect the way we think about the big picture.
The final steps are to:
a) Get feedback from your colleagues fairly early on, so that you are not entrenched in your way of doing things yet.
b) Practice your talk until you can do it in your sleep.

Some final tips for crafting your talk:
1) Know your audience. Present something that they will enjoy, for scientists this usually means tailoring the level of technical detail (and amount of introductory material) to your audience.
2) Anticipate questions and put the answers after your acknowledgements. In addition to allowing you to really nail the Q&A, this is a good way to handle very cool but tangential details that you omit from your main narrative of your talk.
3) Don't bury your conclusions in acknowledgements. You don't want to cleanse your conclusions from people's minds just before the Q&A with a 5 minute long thankyou list. I like to integrate key acknowledgements into the talk. A good way to do this is by showing a thumbnail picture of key people in one corner of the screen when discussing their contribution.

Cooking key to cognition; corals recruit bodyguards; etc.

Metabolic constraint imposes tradeoff between body size and number of brain neurons in human evolution "This limitation was probably overcome in Homo erectus with the shift to a cooked diet."

Corals Chemically Cue Mutualistic Fishes to Remove Competing Seaweeds "Mutualistic gobies and corals appear to represent a marine parallel to terrestrial ant-plants, in that the host provides shelter and food in return for protection from natural enemies."

Bateman in Nature: Predation on Offspring Reduces the Potential for Sexual Selection "substantial yearly variation in the Bateman slope [number of offspring as a function of the number of mates] due to predation on fawns was evident."

Drift-barrier hypothesis and mutation-rate evolution "selection appears to reduce the mutation rate... to a level that scales negatively with both the effective population size (Ne)... and the genomic content "

For a list of my upcoming talks around the world, see my new Darwinian Agriculture Blog.

November 1, 2012

Carnival of evolution

This month's host is Sorting Out Science.