Tag Archives: Max Planck Institute

Tapeworms Can Cooperate or Fight to Control Host

If two tape worms infect the same host, they can either cooperate to thrive, or battle it out for complete control. A new study has found that the parasites actively sabotage each other in a competition to seize control of the host.

A copepod. Image via Fairfax County Public Schools.

 

Tape worms are nasty creatures. They live in the digestive tracts of vertebrates as adults, and often in the bodies of other species of animals as juveniles. Basically all vertebrates may be parasitized by some tape worm; the cow tape worm can grow up to 20 m (65 ft), while the whale tape worm can reach a whopping 30 m (100 ft). They’ve been around for at least 270 million years ago (geologists found them in fossilized feces), and they’re likely going to be around for a long time – it’s only natural that in this time, they’ve developed ways to accentuate their control over the host.

Scientists have long known that parasites can influence host behaviour. In many cases, parasites go through different life cycles in different hosts, thus encouraging the current host to perform action which would transfer the parasite to future cost. But it’s also quite possible for two parasites to inhabit the same host at the same time. Nina Hafer and Manfred Milinski wanted to see what happens when this situation occurs.

The two study parasites at the Max Planck Institute for Evolutionary Biology in Ploen, Germany. For this study, they infected small crustaceans called copepods (Macrocyclops albidus) with multiple Schistocephalus solidus tapeworms. These live in copepods and then move to fish for their next life-cycle stage. The tape worms make the copepods more active and agitated, and thus more likely to be eaten by a fish – thus transferring the parasite to its next host.

Scientists found that when copepods are inhabited by two similarly aged parasites, they become even more active – the parasites are cooperating for the same purpose. However, when an older tapeworm was sharing a host with a younger one, the older animal always came on top.

‘The activity of the host does not reach an intermediate level as a result of the two competing parasites. This suggests that the older parasite is “sabotaging” the younger one’s activity, says Hafer, because “we don’t expect the non-infective parasite to stop what it’s doing,” says Hafer. The older parasite even won out when it was in competition with two younger individuals’, Nature writes.

While it’s easy to understand why they would do this, we don’t yet understand how they do it. As a matter of fact, we don’t understand at all how the parasite influences the host’s behavior. Frank Cézilly, who studies host–parasite interactions at the University of Bourgogne in Dijon, France hopes that this research could ultimately shed some light on that matter. It could be very important to understand how parasites influence their hosts, and sabotage is a relevant and interesting behavior.

“It could be sabotage, but it could be just that the younger parasite can’t overcome [pre-existing] manipulation by the older parasite,” he says.

superconductivity

Superconductivity achieved at room temperature for a fraction of a second

Using a pulse of infrared light, physicists at the Max Planck Institute for the Structure and Dynamics of Matter have turned an insulating material into a superconductor even at room temperature, a property that was retained  for only a few millionths of a microsecond. Superconductivity is a state where a material can conduct electricity with absolute zero resistance, with no loss of energy. Traditionally, the state has been demonstrated in metals and ceramics which typically need to be cooled near to absolute zero temperature (-273 degrees Celsius). This breakthrough in fundamental research might spark further interest in achieving the much sought after superconductivity state at room temperature.

Resistance is futile

Star Trek’s Data – ruining jokes since 1987. Via University of Wisconsin.

If you’ve ever touched a high power cable or even a simple appliancea like a hair dryer, you’ve certainly felt how hot it can be. The heating you’re sensing is due to the resistance of material that various wires and electrical components are made of. When electricity passes through these materials, impurities cause electrons to bounce off into atoms, causing them to shift position. This motion is translated into temperature (the vibrations of atoms). Heat is wasted energy (unless you wanted that way for heating) and even power lines that use very good conductors lose roughly 6% of the power they transmit. As such, there are many fields that are interested in using materials that have as little resistance as possible… ideally zero!

[NOW READ] The minimum and maximum temperatures in the Universe

Superconductivity was first discovered by Dutch Physicist Heike Kamerlingh Onnes in 1911, when he and his students found that the electrical resistance of a mercury wire cooled to about 3.6 degrees above absolute zero made a dramatic plunge. The drop was enormous – the resistance became at least twenty thousand times smaller. Since then, much work was made to improve our understanding of this peculiar state. We now know superconductivity is a quantum mechanical phenomenon characterized by the Meissner effect – the complete ejection of magnetic field lines from the interior of the superconductor as it transitions into the superconducting state.

Not all metals can be superconductive. While most metals, like copper or silver, also experience a severe drop in electrical resistance when cooled near to absolute zero, they still show some resistance. While only a couple of materials capable of reaching superconductivity state were identified in 1980, today a whole slew of new alloys have been recognized thanks increase interest in the subject. These include  niobium-titanium, germanium-niobium or niobium nitride. The most promising materials belong to a class based on ceramic materials, like the compound yttrium barium copper oxide (YBCO), which can be superconductive at only minus 200 degrees Celsius.

In effect, superconductivity can be segmented in low temperature conductors and so-called “high temperature” conductors, but even the best of the latter must be cooled below -140 °C to achieve near zero resistance. While we now understand how low temperature conductors like lead work, the same can’t be said about the high temperature ones as many of its mechanisms remain a mystery.

Spooky quantum mechanics

his picture shows a light-induced redistribution of interlayer coupling in YBCO. In the superconducting state, the pump light enhances the superconducting coupling between the copper-oxygen bilayers at the expense of the superconducting coupling within the copper-oxygen bilayers. A similar case is found for the normal state, that the laser light induces a superconducting coupling between the bilayers, meanwhile weakens the precursor superconducting coupling within the bilayers. Credit: Jörg Harms/MPSD,CFEL

his picture shows a light-induced redistribution of interlayer coupling in YBCO. In the superconducting state, the pump light enhances the superconducting coupling between the copper-oxygen bilayers at the expense of the superconducting coupling within the copper-oxygen bilayers. A similar case is found for the normal state, that the laser light induces a superconducting coupling between the bilayers, meanwhile weakens the precursor superconducting coupling within the bilayers. Credit: Jörg Harms/MPSD,CFEL

An important step forward in understanding how these conductors work was made by Max Plank researchers – including Wanzheng Hu, Daniele Nicoletti, Cassi Hunt and Stefan Kaiser lead by Andrea Cavalleri – whose findings might ultimately help materials become superconductive at room temperature.

The team focused their attention on the aforementioned Yttrium barium copper oxide (YBCO), whose crystal structure consists of stacks of two closely spaced copper-oxygen planes, with thicker intermediate layers which contain barium as well as copper and oxygen.  Previous studied showed how pairs of electrons can already hop between the closely-spaced copper oxygen layers at temperature past its critical superconductive temperature of minus 180 degrees Celsius, but not across the large distance to the next bilayer unit. This effect has been likened to a “tunnel”, meaning they can pass through these layers like ghosts can pass through walls.

“Our goal is to use light pulses to stimulate the electron pairs to tunnel freely between all layers at higher temperatures, thus effectively increasing the critical temperature,” explains Hu.

Last year, in 2013, the team reported an amazing discovery. They discovered that when YBCO was irradiated with infrared laser pulses it briefly became superconductive at room temperature. Specifically, oxygen atoms that sit in the gap between pairs of copper-oxygen planes were targeted. The distance between these oxygen atoms and the planes has been found to be directly related to the critical temperature. Don’t jump off your chair, just yet! The superconductive state only survived for a couple of picoseconds (trillionths of a second).

superconductivity

Resonant excitation of oxygen oscillations (blurred) between CuO2 double layers (light blue, Cu yellowy orange, O red) with short light pulses leads to the atoms in the crystal lattice briefly shifting away from their equilibrium positions. Credit: Jörg Harms/MPI for the Structure and Dynamics of Matter

For some time, the scientists were left scratching their heads regarding the specific mechanisms involved. Now, the Max Plank team published a new paper in Nature where they explain what they believe had had happened. To solve the riddle, they enlisted the help of fellow physicists at the LCLS in the US, the world’s most powerful X-ray laser.

“We started by again sending an infrared pulse into the crystal, and this excited certain atoms to oscillate,” explains Max Planck physicist Roman Mankowsky, lead author of the current Nature study. “A short time later, we followed it with a short X-ray pulse in order to measure the precise crystal structure of the excited crystal.”

Besides causing the atoms to oscillate, the infrared pulse shifted their positions in the crystal as well. This briefly caused the copper dioxide double layers thicker – by two picometers or one hundredth of an atomic diameter – while the layer between them was thinned by the same amount. The increments might seem minute, but these were enough to increase the quantum coupling between the double layers to such an extent that the crystal turned superconductive, albeit for a fleeting moment.

Why we need superconductivity

Practical applications that use superconductivity today include  magnets for nuclear spin tomography or particle accelerators. However, if superconductivity can be achieved at lower temperatures, thus reducing the energy required to cool the crystals, then a whole new realm of possibility might unfold before our very eyes – some straight from science fiction like the quantum locked superconducting disk that’s been charming people on the web for some years now. What happens in this particular case is small weak points in a thin superconductor allow magnetic fields to penetrate, locking them in. These are called Flux Tubes.

superconductive quantum locking

Image: YouTube

If the quantum locking effect can maintained with low energy input, we might see things like zero friction rails that seemingly levitate at high speeds. Check out the video below for some mind bending demonstrations.

Chimp fashion? For the first time, scientists observe a fad in the animal world

It’s a trend that has taken a chimp group by storm: a blade of grass dangling from an ear. All the cool chimps are doing it and, well, you’re not cool if you don’t do it! It’s the first time when chimps have created a tradition with no practical and discernible purpose – in other words, it’s the first time when chimps exhibited a fashion sense.

Just to be completely clear from the start, scientists have used the term “fad” to refer to a a social endeavor with no (apparent) communication/evolutionary benefit, and one which also seems to be free of genetic or ecological factors.

“Our observation is quite unique in the sense that nothing seems to be communicated by it,” says study author Edwin van Leeuwen, a primate expert at the Max Planck Institute in The Netherlands.

The challenge of this study was actually determining if this was actually a fad, and not something chimps were just doing randomly. In order to figure this out, van Leeuwen and his colleagues spent a year observing four chimp groups in Chimfunshi Wildlife Orphanage Trust, a sanctuary in Zambia. Even though all chimps lived in the same grassy landscape, only one group of chimps was doing the grass-in-ear thing. There was no other factor that scientists could observe (genetical or ecological) that could cause them to do this – it was simply a cultural fad.

Lydia Luncz, a primatologist at the Max Planck Institute in Leipzig, Germany, who was not involved with the research is convinced by the study. She believes that one or several chimps were doing this, and it just passed on through the “natural transmission” of new behavior. The trend setter in this case is Julie – the chimp who started this in 2010. Julie the inspired all the 11 chimps in her group to do the same.

“Everybody can wear rings in their ears, but you just have to come to the idea to do it.”, van Leeuwen explains.

The tradition goes on now, even with chimps who never met Julie.

“The chimps would pick a piece of grass, sometimes fiddle around with it as to make the piece more to their liking, and not until then try and stick it in their ear with one hand,” van Leeuwen says. “Most of the time, the chimps let the grass hanging out of their ear during subsequent behavior like grooming and playing, sometimes for quite prolonged times. As you can imagine, this looks pretty funny.”

As funny as it may seem, this behavior is, in essence, similar to what many humans do. At its core, it’s not different from wearing earrings, or funny hats.

“Any kind of subculture fad in human culture, I’d say, could be the parallel to this grass-in-ear behavior,” van Leeuwen says. “Perhaps wearing earrings or certain kinds of hats.”

Scientific Reference: A group-specific arbitrary tradition in chimpanzees (Pan troglodytes)

Does the Moon actually affect our sleep? The answer is likely no, study shows

The Moon and sleep

Moon Sleep PatternFor centuries, people have thought that the Moon affects sleep patterns. But does it really? Many people report increased sleepiness when there is a full moon, and there have even been some studies linking the Moon with sleep patterns. However, a new study conducted by researchers from the Max Planck Institute of Psychiatry in Munich did not observe any correlation between human sleep and the lunar phases.

It’s a really old belief, and you’d expect someone has looked into it and figured it out by now, right? Well, so far, studies on the issue have had varying and contradicting results. The effects were very rarely estimated with an actual EEG. In some studies women appeared more affected by the moon phase, in others men. In others, there were no significant influences. So how do you avoid having yet another inconclusive study, and show actual statistical relevance?

Well, as any undergrad will tell you – get a bigger sampling size! That’s exactly what scientists did, analyzing the sleep data of overall 1,265 volunteers during 2,097 nights. All in all, that’s over 2 million nights of sleep.

“Investigating this large cohort of test persons and sleep nights, we were unable to replicate previous findings,” states Martin Dresler, neuroscientist at the Max Planck Institute of Psychiatry in Munich, Germany, and the Donders Institute for Brain, Cognition and Behaviour in Nijmegen, Netherlands. “We could not observe a statistical relevant correlation between human sleep and the lunar phases.”

Publication Bias

They then looked onto pre-existing studies, to compare the results, and they found a very interesting thing. While most published studies tended to highlight a connection between the two, they found a lot of unpublished data which came back with negative results. This is probably the result of the so-called publication bias – or the drawer problem.

Basically, what happens is that studies that find a connection are more likely to be published than studies which don’t. So if your study found that the Moon is connected to sleep, it’s more likely to be published than if it hand’t. This is a huge problem in research, especially in medical research. If you conduct trials regarding a drug or a treatment and it works, it’s quite likely to be published. Howeveer, if you do the same thing and it doesn’t work (even if you conduct several trials), the results are much less likely to be accepted into peer reviewed journals. It’s easy to understand why this causes big problems in the long run.

The same thing seems to be happening with the Moon and sleep.

 “To overcome the obvious limitations of retrospective data analysis, carefully controlled studies specifically designed for the test of lunar cycle effects on sleep in large samples are required for a definite answer,” comments Dresler.

Source: The Max Planck Institute