Search our site

Custom Search

Thursday 31 July 2014

Squid Lady Parts

NOAA OKEANOS Explorer Program , 2013 Northeast U. S. Canyons Expedition
This bobtail squid is very surprised at the absence of squid gynaecologists! Image credit: NOAA OKEANOS Explorer Program

I first saw squid pimples in 2006, on a research cruise in the Sea of Cortez. The little bumps around the female’s mouth looked exactly like whiteheads, as if squid could get clogged pores. They even oozed white stuff when you squeezed, but it wasn’t pus.

It was sperm.

I was just beginning as a graduate student, learning to extract eggs and sperm from Humboldt squid in order to study fertilization and development—or, as I glibly described my thesis, “squid sex and babies.” Though technically I wasn’t studying sex, since in squid copulation is separate from fertilization. Females mate and store sperm for weeks or even months before laying eggs.

Picture of a clutch of squid egg (species type unfortunately not specified) cases on display at the Monterery Aquarium. Photographed on April 2, 2007.
We don't know how the female market squid who laid these egg cases selected which sperm was used to fertilize them. Image credit: "SquidEggCases-MontereryAquarium-April2-07" by User:Captmondo. Licensed under CC BY-SA 3.0 via Wikimedia Commons.
Males help out by pre-packaging their sperm into complex needle-like structures called spermatophores. Each spermatophore can ejaculate (yes, independently!) to become a spermatangium, a sticky sperm mass that attaches to the female’s skin. Then sperm from this mass moves into the little pimples I saw, which are called spermathecae. Confused yet? I sure was!

In the ship’s laboratory, we were able to fertilize eggs with sperm from spermatophores, spermatangia, and spermathecae[1]. But I’m pretty sure squid don’t lay their eggs in Petri dishes, so this doesn’t tell us a whole lot about natural reproduction. Which of the three sperm sources do females use to fertilize their eggs? Why bother with all the processing steps? Does it have to do with female selection or sperm competition?

No one knows, which is a bit surprising because spermatophores themselves have been studied quite intensively. Videos of spermatophore ejaculation and attachment can be found online, and I’ve written about more than one exciting new study. But this is the first time I’m writing about spermathecae, and it’s not because of recent research—it’s to popularize the lack of it.

Friday 25 July 2014

The Quest for Invisibility

Since long before Harry Potter, scientists have been searching for a way which can allow things to pass us by unnoticed. The invisibility cloak which features in J.K. Rowling’s books may seem magical and otherworldly, but in fact devices which have the effect of making objects completely disappear are much more tangible than you’d think. While they may not look like a silky blanket, cloaking devices are very effective at manipulating signals and jamming detectors so as to obscure the truth about their location.

So there it is, we’ve done it. We have successfully created magic and are able to hide enormous ships or helicopters from being spotted by the enemy – haven’t we?

Well, not exactly. The perfect cloaking device is still just a theoretical concept. Camouflage paint is often applied to try and confuse the eye, “stealth” coatings are used to hide from radar, while cooling techniques are employed to reduce the amount of infrared emission coming from the object trying to stay hidden. However, while these techniques are effective at helping to disguise ships and aeroplanes, we can hardly call them invisible. It is hoped the answer lies in the development of metamaterials – materials which possess properties not found in nature.

Image demonstrating variety of wavelengths of the electromagnetic spectrum
The electromagnetic spectrum covers all wavelengths of radiation, from radar to visible light to x-rays and gamma-rays. Until last year we could only hide things from very specific parts of the electromagnetic spectrum, in some cases by making the object more visible in other parts of the spectrum. Image credit: NASA (public domain)
The development of such materials has huge implications for lens and invisibility devices. The idea of cloaking devices is to create a material which can take an incoming signal, say visible light, and then send it on its way without any interruption from the cloaked object. If you could create a material which can do this effectively enough, it will trick any detectors into thinking there is no object to be seen, since there is no radiation signal to be detected. In theory it’s possible, but there are many obstacles blocking the way.

Wednesday 16 July 2014

How reliable is psychological science?

Things We Don't Know Anymore

TWDK Psychology doodle copyright Giles Meakin / Things We Don't Know CIC
Our psychology editor Malte Elson explores the “replication crisis”, and questions our level of confidence in established psychology. Image credit: Things We Don't Know / Giles Meakin (CC-BY)

The last few years haven’t been easy on psychological science. Don’t get me wrong – the field in itself is flourishing, boasting an ever-increasing number of publications, journals, conferences, faculty positions, and university graduates all over the world. It has gained more and more respect and acceptance, both in academia and society. The case of Harvard evolutionary biologist and primate researcher Marc Hauser’s fraudulent publications was already fading from our minds when in September 2011, the discovery of the scientific misconduct by the Dutch social psychologist Diederik Stapel shattered the grounds of psychological science. In at least 50 cases of scientific fraud that have been discovered by the Levelt Committee, Stapel had doctored, mangled, and completely fabricated datasets to successfully publish in the field’s top-ranked outlets - up to the most prestigious journals like Science. Among Stapel’s highly regarded publications were findings on how untidy environments encourage racist discrimination[1], or how to reduce racist biases in judges' legal decisions on minority defendants[2]. Nullifying the content of these publications constitutes a setback for social psychology, and - to a somewhat lesser extent – society overall.

Although they work in a highly competitive environment, we trust scientists to be committed to finding the truth. And when playing it smart, like Stapel, it is quite easy to abuse this trust for personal gain in the form of a prestigious academic career. Instead of looking for the truth, Stapel was on a quest for aesthetics, for beauty, as he was quoted saying by the New York Times. One might think that it’s not that much of an issue - Stapel got caught after all! Reaching for the stars he committed fraud, but got brought back down to reality when his deeds were unveiled, so the system works. But does it really?

Monday 7 July 2014

Sheffield students make TWDK science videos

We issued our challenge through the university's Venture Matrix™ scheme.
Earlier this year, we set students from Sheffield Hallam University a challenge - to take one of our published science articles, and turn it into a video. Four groups of media students took up the gauntlet, and over the next few months the students created four very different videos.

The students had a total freedom of choice regarding which of our articles they chose, and the style they would use to make the video. Our only condition was that each group choose a different article.

Tuesday 1 July 2014

Mapping spacetime around supermassive black holes

Black holes come in many sizes ranging from tens to millions, or even billions, of solar masses. Their incredible size means they exert immense gravitational power over other objects, and can even warp space-time to such a degree that they behave like lenses and actually bend light around them – a process known as gravitational lensing. In many cases a large black hole will acquire another incredibly dense friend, for example a small black hole or a neutron star, which will orbit the central black hole whilst slowly spiraling into it. These physical systems are known as Extreme Mass Ratio Inspirals (EMRI's), called as such because of the vast mass difference between the two objects.

distorted grid with Earth at the centre demonstrating deformation of spacetime.
Physicists often consider space and time as a single continuum, called spacetime, which consists of the 'usual' three dimensions (up/down, left/right and forwards/backwards) plus time as a 'fourth' dimension. Spacetime is bent by anything with mass - an effect we see as gravity. Image credit: Wikimedia commons
Einstein’s famous theory of general relativity states that any mass will bend spacetime. Black holes, because they are so incredibly dense, will stretch and curve space-time to a much greater degree than our planet ever could. However something relatively tiny, like the Earth, still has an effect. For EMRI's, you can think of this as being like a bowling ball placed on to a taut sheet - the bowling ball will sink causing the sheet to stretch. If you place a marble onto the same sheet, it will also sink a little bit into the sheet because it has its own weight, but the bowling ball makes a much larger dip than the marble.

But getting out sheets, marbles and bowling balls isn’t a very accurate way of modelling these systems – so how is it done? I spoke to Dr Sarp Akcay, a postdoctoral fellow at the University of Southampton and an expert at creating models simulating the orbits of EMRI's.