Thanks, Christi!

If reading the story makes you feel sciencey, Eric explored the science behind using plants for life support on the Science Not Fiction blog. But if reading the story makes you want to kick back and feel mournful, listen to Amanda Palmer’s amazing song “Astronaut.” I’m obsessed.*

*Yes, this entire post was an excuse to post this song.

Savin' the Coral Reefs?

Hi there, blog land. Huge thanks to Miriam for the amazing (scary?) opportunity to guest blog while she is off exploring Eastern California, and for the introduction asserting that I am both credible and cool. I hope to slowly disappoint readers on both counts as the week goes on, ensuring Miriam’s return is met with maximum fanfare and relief.

As Miriam mentioned, I’m studying corals in the Caribbean for my dissertation. With that job comes the obligation to not only save the coral reefs, but have a good time doing it, because after all, everyone wants to be a marine biologist when they grow up, and coral reefs are the coolest things in the ocean, hands down. No pressure, right? During my blog-stint, I’ll expose some behind-the-scenes stories from my job so that you feel better about yours. I’ll reveal whether I am actually saving the coral reefs. I’ll also offer up some of my favorite recent stories from science land in general. I particularly love when things turn out to be way more complicated than we thought they were, which conveniently applies to about 99 percent of discoveries in science.

So, thanks for the welcome, and sorry in advance.

PS: I thought my picture would be kind of unique, and then I pulled out the New York Times Magazine this morning and found this. Apparently, leaping irreverently into gorgeous bodies of water is now a fad and, because it has been discovered by the New York Times, no longer cool. Like I said.

PPS: Dear dive safety officers, I promise to giant stride from now on.

[YouTube="http://www.youtube.com/watch?v=Fa7ck5mcd1o"]

Mega Shark Vs. Giant Octopus is an actual film, due out  May 26.

WordPress makes embedding videos from certain sources tricky, so you must click to view the trailer. But click.  Seriously. Do it.

Update: Trailer has been YouTubed. <phew>

Update, Update: As pointed out by commenter below, the movie stars Deborah “Debbie” Gibson. Yes, that Debbie Gibson.

Update, Update, Update: We all know how this movie must end, right?

(via io9)

The Twilight and Buffy vampire ecology models were not the first to plumb the mysteries of vampire population dynamics – mathematicians and economists got there first. Mark Strauss has a nice writeup of the wrangling in the vampire literature:

But, this gauntlet had been barely thrown down before it invited a rebuttal from mathematician Dino Sejdinovic. In his article, “Mathematics of the Human Vampire Conflict” (Math Horizons, November 2008) Sejdinovic faults Efthimiou and Gandhi’s logic, since they have not “accounted for the birth-rate of non-vampires and death-rate of vampires (actually the death-death-rate since they are already dead, but when they die again they should stay dead but stop being living) due to close encounters with stakes, garlic and holy water.” Moreover, “vampires are presented exclusively as greedy consumers: a rational strategy of managing their human resources is not considered…”

Their research provoked an outraged response from economist Dennis Snower, who in his article “Macroeconomic Policy and the Optimal Destruction of Vampires” (The Journal of Political Economy, June 1982)…Snower argues that the mortal world can manage its resources in a manner that keeps the undead population in check, while simultaneously promoting long-term economic growth.

Strauss points out that all of these models assume that vampires are the top predator. While the Buffyverse model accounts for Slayer predation, clearly the time is ripe an elucidation of the entire supernatural ecosystem. Zombies and werewolves and demons, oh my.

It is a truth universally acknowledged that a hungry vampire must be in want of blood. It is also universally acknowledged that the sucking of said blood makes more little vamplings, whether by direct infection or by a Buffy-esque “whole sucking thing.” Vampires are top predators, and like lions and wolves, their population can’t outstrip their prey supply.

But since there are so many people, why aren’t we awash in vampires? That’s why Laura McLay at Punk Rock Operations Research is skeptical of vampires. Based on a mathematical model of their population dynamics, she calculates that:

The vampire population would either explode or die out, depending on the expected number of offspring per vampire. But if you take into account the fact that vampires live many, many generations (they’re virtually immortal) and may create thousands of offspring, the population explodes (if you assume that each vampire creates at least one vampire, on average, before it dies). With those numbers, vampires would not be living under the radar–they would be everywhere!

But basing her calculation off icky goopy Twilight, McLay makes a critical mistake. She left out human predation on vampires, fetchingly epitomized in Buffy the Vampire Slayer. Brian Thomas, a theoretical ecologist, calculated the vampire ecology and population dynamics of the Buffyverse and found:

This [Thomas' assumptions] results in an equilibrium population of 36,346 humans and 18 vampires. Thomas then notes that interestingly enough the established population of Sunnydale on the show is 38,500 humans, pretty damn close to the equation result. Maybe Buffy needs to cut back on the slaying in order to let the vampires weed out that extra 2100 people, we wouldn’t want human overpopulation to lead to starvation.

But is this equilibrium stable? Will natural fluctuations in the vampire population prevent the equilibrium state from ever existing? Thomas then ran the model using several different initial population sizes and seeing whether they eventually moved to equilibrium, or spiraled off into an abyss where everybody died. Turns out the model is stable and the vampires and humans can co-exist forever! Hooray!

Check out Thomas’ original paper here (PDF).

So, because we are not neck-deep in starving vampires, clearly we are living in the Buffyverse. Down with mooshy sparkly vampires & limp, passive heroines! Up with snarly-faced evil vamps and ass-kicking Slayers! Now where’s my activated Slayer powers?

Punk Rock Operations link via Boing Boing, Buffyverse Ecology via JEByrnes a long time ago

SPOILER WARNING: This entire post is a giant spoiler for the Battlestar Galactica Season 5 4.5 finale, so I’ve tucked it behind the fold.

Battlestar Galactica ended with a bit of an anti-technology whimper. Humans and Cylons alike tossed their Vipers and their antibiotics into the sun in exchange for a new start. Alongside pre-speech humans, space warriors scattered over Earth, hunting and gathering and farming their way into our own glorious future.

But what was the Earth of 150,000 years ago really like? What was the climate like in Tanzania (where Adama mopes in his cabin) and Britain (where the Chief mopes in exile)? What giant predators might Lee encounter as he explores? And what is mitrochondrial Eve, anyway?

150,000 years ago, the Earth was in the midst of the the Pleistocene Epoch.  The continents were in about the same positions and many of the same plants and animals were doing their thing. But the climate was wildly different. Glaciers rose and retreated and rose and retreated, changing the world’s ecosystems each time. And 150,000 years ago was the maximum of the second-to-last, or penultimate, Pleistocene glaciation. (The final glaciation is the one we think of as the Ice Age, that ended only 10,000 years ago.)

Because of the penultimate glaciation, the African climate was colder and drier than today. North Africa was probably still desert and central Africa a grassland. But the biggest different is in Europe – southern Europe was a chilly steppe and Britain may well have been frozen under the Munsterian glacier. The Chief’s self-imposed exile may be even colder and more exile-y  than he thought, what with starving on top of a giant pile of ice. Maybe he’s really in exile on the Canary Islands?

Africa 150,000 years ago. From Oak Ridge National Laboratory.

The Pleistocene is also known for vast herds of giant mega scary mammals. And it seems like most of these would have been around to eat or be eaten by the Galactica survivors. The steppe mammoth and the European jaguar roamed southern Europe, while the Americas were covered in direwolves and giant sloths and 10-foot tall short-nosed bears. African animals, which were least affected by the late Pleistocene extinctions, would have looked relatively similar to today. Which is to say that they were big and hungry and scary.

The last thing that many of the Fleet survivors saw...

What about Hera as the mitochondial Eve, the mother of us all? That is a real biological concept, nicely explained by Peggy over at Biology in Science Fiction:

Unlike the chromosomal DNA which we inherit equally from both parents, our mitochondria are inherited only from our mothers. That means that geneticists can use the sequence of our mitochondrial DNA to follow maternal inheritance². They followed this back for many many generations, until they arrived at the most recent woman who is the ancestor of all presently living humans. She is “Mitochondrial Eve” and she lived roughly 150,000 – 200,000 years ago….

She’s not our most recent common ancestor or even our only common ancestor. She’s not the only woman who was living at the time. She may not be the our common ancestor for chromosome 1 or 7 or 20.

So, 150,000 years ago, Tanzania was pleasant (unless you got eaten or trampled), the Chief was probably not in Britain (unless he was living on a glacier),  Lee should have explored the supercool sloth-ridden Americas (until he got eaten or trampled), and Ed Yong’s theory of Starbuck’s demise is reasonably likely:

Perhaps when Lee turned his head, Kara was quietly eaten and carried away by a leopard.

And in fact, the Galactica survivors may not have survived very long at all. According to mitochondrial genetic evidence, humans almost went extinct 150,000 years ago. The population could have been as small as 2,000 individuals – so not only might the Galactica survivors have killed most of the primitive humans, but they subsequently died off themselves.

Welcome to 150,000 years ago! Please enjoy your nasty, brutish, and short stay here in Pleistocene Earth. Though I would love to ride magnificently about on a giant ground sloth, I’d really rather have modern medical care and the internet.

From danah’s talk:

I’m going to share my research in three acts:
1) How did social media – and social network sites in particular – gain traction in the US? And how should we think about network effects?
2) What are some core differences between how teens leverage social media and how adults engage with these same tools?
3) How is social media reconfiguring social infrastructure and where is all of this going?

The fearsome Dalek, they of the mighty plunger and whisk weaponry, might be invading our waterways. Evidence of the impending Dalek aquatic invasion was uncovered in a pond in the UK.

The 42-year-old said: “I’d just shifted a tree branch with my foot when I noticed something dark and round slowly coming up to the surface.

“I got the shock of my life when a Dalek head bobbed up right in front of me.

As if the zombie apocalypse wasn’t bad enough. Now where’s my sonic screwdriver? And my David Tennant?

(And if you’re like me and are compelled to peek behind the illusions’ curtain, check out side view photos here and here.)

Via io9 and Martini-Corona