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By Stephen Luntz

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The Heart of Grief
Coral Killer Diagnosis
Crabs Take Direction
Cancer Prognosis Predictor
Antarctic Map Fills in the Gaps
Koalas Bellow Their Appeal
Remnants of Gondwana
Endangered Species off the List
Cystic Fibrosis Trial Success
Record-Breaking Stellar Jet
It’s Light, But Not As We Know It

The Heart of Grief

A broken heart isn’t just a metaphor based on ancient anatomical ignorance. The loss of a loved one really can increase cardiac risk, and a collaboration of Sydney universities and medical institutions has investigated how.

Dr Anastasia Mihailidou of the Sydney Medical School reports that in a study of 63 people who lost a spouse or parent all of them had heightened heart rates and blood pressure variability 2 weeks afterwards.

Six months after the death, heart rates were back to normal but blood pressure continued to fluctuate over the course of 24 hours. Remarkably, this was the case for all members of the group, with no subgroup returning to normal. Mihailidou suggests this may be indicative of people not sleeping well.

The results were measured in comparison with a control group of 78 people whose loved ones returned home from hospital. The controls generally did not experience similar symptoms.

Mihailidou notes that the recruitment of grieving relatives, conducted through the Royal North Shore Hospital, is not easy, and the study may never be repeated. Previous studies have looked at longer-term effects, such as a year after the death.

“The results indicate that someone who is grieving and who is already experiencing blood pressure issues would find these problems amplified during or because of bereavement,” Mihailidou says. “These changes aren’t large, but if heightened blood pressure variability goes unnoticed it can cause problems.”

The findings were presented at the American Heart Association’s Annual Scientific Meeting. A new trial is commencing on methods of treatment for people experiencing grief.

Coral Killer Diagnosis

A technique widely used for identifying human diseases could be adapted to save coral reefs, according to Mr Joseph Pollock of the ARC Centre for Excellence for Coral Reef Studies.

“Current classification of coral diseases is mostly based on a description of how the coral has deteriorated, such as the pattern of tissue loss and abnormal colours,” Pollock notes. “This is an ineffective way to identify coral diseases because different diseases can often look very similar. For instance, in the Caribbean alone, more than six ‘white’ diseases show the same characteristics of tissue loss exposing white coral skeletons.”

One of Pollock’s doctoral supervisors, Dr David Bourne of the Australian Institute of Marine Science, says that many people are working on coral diagnostic tests “but we want ones which are robust. We’re looking for something that is rapid and routine”. The researchers also want to detect the presence of pathogens in water samples taken from reef environments.

Bourne believes that quantitative-PCR provides this as it has the capacity to detect the genetic fingerprint of tiny numbers of bacteria in a cup of seawater. He notes that corals are harder to work with than human tissue as we don’t have the same availability of cell lines to conduct research on.

“There are a lot of monitoring programs going on to look at diseases in reefs and see if these are changing,” Bourne says. “We hope to see things from a microbial point of view, for example seeing if particular diseases get more common in warmer conditions.”

Bourne accepts that open systems such as coral reefs do not lend themselves to the use of the antibiotics that have made it so important to distinguish between viral and bacterial diseases in humans. However, this does not mean we will be diagnosing problems that cannot be treated.

“With human diseases most of the advances have happened through things like clean water,” Bourne says. “It will be the same here. The best treatment is preventative measures. We may be also able to see if snails or fish are acting as vectors, transmitting disease, and we might be able to manage those.”

The research is published in PLoS Pathogens.

Crabs Take Direction

Fiddler crabs respond to their poor eyesight by becoming habituated to intruders based on direction, a student has discovered in the course of an Honours project.

The crabs live on mudflats, without vegetation or even much terrain, so they substitute height for depth perception, with eyes on stalks that can see over very small obstacles. The crabs have learned to conduct sophisticated calculations to determine whether an approaching crab is in a position to steal their burrow (AS, March 2003, p.11).

“The crabs treat anything above the horizon of their eyes as a predator, and anything below as a mate,” says Ms Chloe Raderschall, a research assistant at the Australian National University’s Vision Centre.

For her undergraduate Honours project Raderschall placed black objects the size of a ping pong ball on some fishing wire and made them swoop over crabs in their natural environment.

“We did two dozen runs of a dummy approaching from direction A without attacking the crabs, and within five runs the crabs started to ignore it,” Raderschall explains. “When we switched to another dummy coming from direction B, the crabs were scared witless and headed straight to their burrows.” Returning to direction A saw the crabs regain their comfort.

In each case the object was placed at the same height, so the crabs were not reacting to its angle to the ground. The timing of the dummy’s movement was also kept consistent so the only difference for the crab was the direction from which it came.

The finding demonstrates that crabs do not distinguish potential predators from other intruders by their shape, as previously thought, but through specific habitation responses. Objects that behave in a manner similar to those that have not posed a threat in the past are ignored.

Raderschall says this is necessary because the crabs’ eyesight is so poor that “apart from very simple visual cues, they don’t really have other ways to detect predators, and this study provides clues as to how animals with relatively poor vision can adapt and survive over time”.

The crabs maintain an exceptional awareness of the location of their burrow relative to wherever they may be, and this may be useful for them to distinguish directions of motion. Raderschall is not sure how the crabs would respond if moved to a location without a burrow.

The findings were published in the Journal of Experimental Biology.

Cancer Prognosis Predictor

The potential exists for the cells around breast cancers to provide predictions of a patient’s survival prospects, greatly easing the treatment for some individuals who currently experience chemotherapy that may be more damaging than their version of the disease.

“While in recent years there have been fantastic advances in the treatment of breast cancer there has been no way of predicting its progress,” says Helen McCosker, a PhD student at the Queensland Institute of Technology’s Institute of Health and Biomedical Innovation. Overtreatment of patients with relatively benign cancers can be the cause of significant unnecessary suffering (AS, Jan/Feb 2010, p.4).

McCosker examined proteins present both within cancers and in the surrounding cells, and compared these with the survival of a group of patients considered to have a poor prognosis on existing tests. She found that the presence and absence of certain proteins were predictive – a mathematical model based on a combination of certain growth factors and proteins associated with the structure of cells around the tumour could accurately indicate an individual’s prospects.

“This test should identify those patients who need their cancer removed but require no further treatment; those who need the tumour removed but also require additional treatment – for example, chemotherapy; and those who need more vigorous treatments,” McCosker says. Her study uses tissue already collected in biopsies, so no additional testing would be required.

McCosker did not distinguish in her sample between patients with cancers that proved highly invasive in the first instance, and those where the cancer returned after apparently successful treatment. However, a larger study may be able to use such distinctions to further refine diagnoses.

Antarctic Map Fills in the Gaps

A new map has revealed much of the bedrock beneath Antarctica, including valleys stretching hundreds of kilometres inland that lie up to 1000 metres below sea level.

BEDMAP2 was prepared by the British Antarctic Survey using observations from many groups. The Australian Antarctic Division (AAD), the Antarctic Climate and Ecosystems Cooperative Research Centre and the universities of Texas and Edinburgh were responsible for many of the 27 million data points that went into making it under the name Project ICECAP.

Dr Roland Warner of the AAD says the information will assist new computer models of how ice will flow across Antarctica will change as floating ice shelves at the continental margins are exposed to warmer oceans. “These improvements are central to more accurate predictions of how Antarctica will respond to climate change and what that means for future sea level,” Warner says, adding it is increasingly clear that “Antarctica is not the slowly changing system we thought it was”.

Of particular interest is the topography of valleys through which large glaciers flow to reach the oceans. A detailed map of the rock surface of the Aurora Subglacial Basin, south of Casey Station, was published in Nature in June 2011, revealing enormous fjords far inland carved in an era when the ice advanced and retreated in response to climatic changes.

There are no currently orbiting satellites with sufficiently powerful radar systems to penetrate more than a kilometre of ice, so the observations were made using aeroplanes and, in the old days, even dog sled teams. ICECAP provided the data for an area of more than 1000 km radius around Casey Station.

Warner quotes Texan colleague Dr Duncan Young, saying: “Previously we could pretty much have said ‘Here be dragons’ over a lot of it”. Two large patches of the continent remain almost unmapped, along with some areas below sea level around the continental margin, resulting in deceptively smooth sections of the new map.

In the event of major melting of the East Antarctic Ice Sheet, many areas that are currently under ice will find themselves flooded by the newly raised ocean, but over time the removal of such an enormous weight will cause the continent to rise upwards, as parts of North America and Europe have done after the last Ice Age.

Koalas Bellow Their Appeal

Male koalas have been revealed as one of the few animals with a permanently descended larynx. By having their larynx attached deep in the thorax, rather than close to the jaw like the majority of mammals, they are able to make a much deeper sound than other animals of similar size.

Dr William Ellis from the University of Queensland’s School of Biological Sciences, who reported this finding in Experimental Biology, believes that the koala bellows act as a way of attracting mates who prefer larger males.

Ellis recorded a range of male koala bellows and fed them through a spectrogram. He then took on the rather challenging task of persuading the notoriously grumpy males to sit in MRI machines so he could visualise their vocal tracts.

Larger males are able to guard more territory and are more successful at attracting mates. He observed that females are attracted by the bellows. While it is possible the advantage of a deep grunt is that it remains audible over a greater distance, Ellis thinks it is more likely that the females recognise that the deeper sounds indicate a larger male. Other males may also find a deep bellow a deterrent.

“This confirms our impression that intense sexual selection in the koala operates despite their seemingly solitary nature,” Ellis says. Sexual competition is often thought of as being a matter of intense physical combat or frequent competition, but Ellis says it is now clear that males can compete without ever physically interacting. “It makes sense, because you don’t really want to fight in trees where you can fall out, so it is useful to gauge an opponent’s size and avoid dangerous encounters.

“Koalas are an excellent model for investigating parameters of mate choice and evolutionary ecology, as well as being an iconic, if vanishing, species,” Ellis argues. He notes they are easy to track given their low mobility, and seem to have a social organisation while also being solitary. The long period that offspring stay with the mother also makes paternity testing easy.

Female koalas also bellow, but Ellis admits: “We have no idea what the role of the female bellow is. No one has done any research.”

Remnants of Gondwana

A German–Australian collaboration may have solved the mystery of the Indian Ocean seamounts, including Christmas Island. In the process they have offered a new vision of how such volcanic objects can form.

The German research vessel Sonne mapped and sampled 60 seamounts 1–3 km high off the north-west Australian coast. The results, and conclusions drawn, have been published in Nature Geoscience.

“These particular seamounts lie in a 200 km-thick band almost parallel to the Equator,” says Prof Dietmar Müller of the University of Sydney.

“In contrast to other seamount zones, such as Hawaii or the Canary Islands, their existence was something of a mystery because there was no known hotspot nearby. The seamounts’ ages also didn’t show a progression in any particular direction – something we’d normally expect to see in volcanoes formed over hotspots.”

Analysis of the samples revealed the presence of continental rocks at unexpected distances into the ocean, forcing a further rethink of the formation process. The team concluded that continental break-ups are messier than previously realised.

“When Gondwana was splitting apart millions of years ago, small fragments of deep, gooey continental rocks managed to get separated, lost, buried and then drawn out underneath the Indian Ocean while India and Australia drifted apart,” says PhD student Ana Gibbons. “Since these continental leftovers were incubated in the depths of the Earth’s crust for about 200 million years, they were still quite warm and buoyant. They gradually floated up when their thick continental blankets were replaced with the Indian Ocean’s younger and thinner crust.”

The rising continental rocks created what Gibbons calls a “lava flow cocktail” where impurities in the lava lowered the melting point so it could flow more easily. She refers to the seamounts as the party-hats left behind when the cocktail party was over.

Gibbons is unsure whether any other seamount provinces were formed in the same way, noting that the Atlantic break-up, for example, was a much simpler process, whereas the formation of the Indian Ocean occurred with the Indian plate changing direction part-way through.

The seamounts off north-western Australia have been explained.

Endangered Species off the List

The US Endangered Species Act (ESA) is considered a world leader in protecting threatened species, coming as it does with legal force. However, a new study has noted how few endangered species are actually making it onto the Act’s list by comparing it with the International Union for the Conservation of Nature’s Red List.

While such a comparison may seem obvious it took a PhD student from the University of Adelaide’s School of Earth and Environmental Sciences to point the discrepancy out as part of a study published in Conservation Letters in collaboration with three other universities, only one of them American.

Mr Bert Harris suggests that the surprising oversight is a result of the Red List gaining relatively little attention in the United States compared with the ranking given by a separate organisation, NatureServe. Previous studies have shown that many species classified as threatened or endangered by NatureServe are also not protected under the Endangered Species Act.

As a bird specialist Harris noted the absence of Kittlitz’s murrelet, the ashy storm petrel and the cerulean warbler from ESA listing. The Red List considers these critically endangered, endangered and vulnerable, respectively.

“The ESA has protected species since its establishment in 1973, and it may have prevented 227 extinctions. However, the implementation of the ESA by successive US governments has been problematic, including poor coverage of imperiled species, inadequate funding and political intervention,” Harris says.

Kittlitz’s murrelet, for example, was left off because climate change is considered the primary threat, making action to protect it difficult. Other species have been classified as “warranted but precluded” on the basis that higher priorities exist.

Harris also blames the vagueness of the US government’s definitions of “endangered” and “threatened” in comparison with the more rigorous IUCN assessment.

Harris is not aware of a similar comparison of Australian species with IUCN listing.

Cystic Fibrosis Trial Success

Participants in a trial of a drug treatment for a rare form of cystic fibrosis (CF) have experienced an improvement in symptoms. The results have given hope to the researchers at the Lung Institute of Western Australia (LIWA) who designed the drug and are now trialling a similar drug against a far more common variety of the disease.

Cystic fibrosis is characterised by abnormal salt transport, leading to secretions that interfere with breathing and make sufferers vulnerable to lung and sinus infections. A number of mutations can cause CF, but two-thirds of cases involve ΔF508 in which three nucleotides are missing.

LIWA produced the VX-770 drug treatment against the less common G551D mutation, with a paper published in the New England Journal of Medicine recording much better lung function and smoother heart rates among those taking part in a trial. Participants also gained weight, which can be difficult for CF sufferers.

Ernie Bindel, a CF patient who took part in the trial, said: “This is the longest period I have remained out of hospital in my life. Overall I feel better, cough less and can take part in more physical activities.” The fact that VX-770 is administered orally was also appreciated.

LIWA director Phil Thompson says the same techniques used to design VX-770 have been applied to the creation of VX-809 for the ΔF508 mutation. “The two protein abnormalities are quite similar, so the drug design just required a small tweaking of the way the protein folds.

“If it is anywhere near as good as 770 a large number of patients will be looking at reasonably effective treatment,” Thompson says. “And that is for adults who already have quite a bit of lung scarring. The future is even better for children.

“Currently the majority of CF therapy is aimed at offsetting the downstream effects. This is the first to get close to offset the gene. It is such a big gene that repairing it would be a big challenge, so the next step is to patch the protein.

“The only other approach that might be this effective would be stem cells in the lung. That is in its early infancy.”

Record-Breaking Stellar Jet

The longest jet ever observed being expelled from a star has been located in the Large Magellanic Cloud (LMC). At 46 light-years long, more than ten times the distance from the Sun to the nearest star, it is more than twice the estimated length of any other known stellar jet and challenges our ideas of how such jets are formed.

The jet’s origin is Sanduleak’s star, which is named after Nicholas Sanduleak who also discovered the progenitor star for Supernova 1987a, the last supernova visible to the naked eye, which is also located in the LMC.

Most researchers consider Sanduleak’s star a symbiotic star where mass is being transferred off a red giant and onto a nearby white dwarf. However, Dr Francesco Di Mille of the Australian Astronomical Observatory says this is still disputed. So much interfering dust surrounds the star that the question has yet to be settled.

Di Mille notes that theoretical models have not been constructed to explain jets this long “simply because nobody would ever have bet that such a giant stellar jet could exist”. The best estimates of the next longest jets are of around 20 light-years. However, these are for stars within our galaxy, whose distances can often not be measured accurately, making the jet lengths unreliable. The distance to the LMC has been confirmed in multiple ways, so Dr Mille is confident of the figure in this case.

Based on estimates of the jet’s velocity Di Mille has calculated the outburst producing the star to have begun around 10,000 years ago, but he says there are many unknowns, including whether interstellar material may be slowing the jets’ progress.

Di Mille says his team chose to focus on Sanduleak’s star because they were exploring the nebulae that surround symbiotic stars. “We never expected to find something of these dimensions,” he says.

The LMC is far smaller than our own galaxy, but contains some spectacularly large objects, including the Tarantula Nebula, the most active star-forming region in any nearby galaxy.

It’s Light, But Not As We Know It

A Swedish/Australian collaboration has confirmed a quantum physics prediction once considered almost impossible to test.

One of the many ways in which the quantum world defies our classical brains is in the formation of virtual particles. These particles, which can appear even within a vacuum, exist for only a very short time. While they are virtual they cannot be directly measured, but under some circumstances these particles become real and are responsible for such effects as Hawking radiation from intense gravitational fields and carrying energy to and from a patient in an MRI machine.

In the 1940s Dutch physicist Hendrik Casimir predicted both a static and dynamic effect from the conversion of virtual photons to their real equivalents. The static effect was confirmed by the observation that two exceptionally close mirrors are pushed together because the photons that spring into existence can exist in more quantum modes outside the mirrors than within the gap between them.

The dynamical Casimir effect (DCE), on the other hand, is much harder to observe. “The DCE was conceived as a kind of thought experiment, sort of like Schrödinger’s Cat,” notes Prof Tim Duty of the University of NSW School of Physics. “According to quantum theory, if one could accelerate a mirror very quickly to near the speed of light, the mirror would radiate light as some of the mirror’s motional energy is imparted to virtual photons lurking in the vacuum, converting them into real photons.”

Accelerating even a small mirror to such speeds would drain all the power from the world’s largest facilities. However, at exceptionally low temperatures superconducting quantum interference devices (SQUIDs) behave like electronic mirrors for microwave radiation.

After tuning a SQUID appropriately, Duty and Dr Chris Wilson of Chalmers University of Technology, Sweden, observed the creation of microwave photons at the frequencies anticipated for virtual photons converted to real photons.

Although the confirmation is unlikely to yield practical applications in the near future, Duty says the circumstances they have created have the potential to expand our knowledge of virtual particles. “It could be a model system, as quantum mechanical as Hawking radiation but a lot easier to access.”

The research was published in Nature.