The modified fruit carbohydrate is made from kiwifruit and has no artificial
additives. It is fat-free and high in fibre, and can be used to replace eggs,
dairy products, butter and cooking oils in a range of commercially-produced
frozen and chilled desserts including ice cream.

The product, called Nektalite, can be used as an emulsifier in frozen products
to make them seem smooth on the palate, says Rossiter. The process, which has
been patented worldwide, relies on “enhancing the natural attributes of the
fruit” by varying pectin and cellulose concentrations so that the pulp behaves
like fat. Commercial production using 5000 tonnes of kiwifruit starts this
autumn at a new plant at Tauranga costing NZ$2 million, about 130 kilometres
southeast of Auckland on the east coast of the North Island.

A NEW ZEALANDER writing a biography of Australian aviator Sir Charles
Kingsford-Smith is looking for descendants of the Sydney doctors who might
have treated Kingsford-Smith in the 1920s and 1930s.

The biographer, Ian Mackersey, believes the descendants may be able to throw
light on a stress-related condition from which Kingsford-Smith suffered
several times while flying. Kingsford-Smith described the condition to
reporters as “aquaphobia”.

Mackersey says Kingsford-Smith was sometimes overcome by panic attacks which
left him physically ill and wanting to land his plane no matter where he was.
It usually happened in bad weather or over the sea.

As a boy Kingsford-Smith nearly drowned at Bondi Beach, and during combat in
the First World War he had his toes shot off. Mackersey belives these two
events probably had lasting psychological effects. In 1929, Kingsford-Smith’s
GP was Dr Callender Wade Sinclair. Later he was treated by Dr Raymond Muller
and, following an incident over the Tasman Sea when his plane and crew were
nearly lost, he was attended by a Dr Banks. Mackersey can be contacted at 12
Kakariki Ave, Mt Eden, Auckland.

SATELLITES are coming to the aid of antipodean farmers. Barry Butler, a NZ
farm computing consultant, has developed a five-part computer program to
enable farmers to use digital satellite images to map their present resources
and plan future land use and stock management.

The maps, generated from satellite information by the program, Farm Tracker,
can be used in the standard way to measure areas of paddocks, vegetation types
and distances between fences and waterlines. But they can also provide
information on soil nutrients and the condition of pastures. At present, farm
maps are drawn up from aerial photographs.

Farm Tracker can be tailored to the needs of a particular farm and the
information it provides can be used for both physical and financial analyses.
About 200 NZ farmers now use the program which runs on any IBM-compatible
system. It will be available in Australia soon.

Marcus King of Industrial Research Ltd in Christchurch subjected a
variety of blooms to sounds at frequencies between 320 and 410 hertz – the
same as that made by the bee Bombus terrestris. ‘It had been suggested that
the sound energy was causing the anther to resonate, ejecting the pollen,’
says King.

But King found that the pollen is not released by the buzz. Instead,
the flower’s pollen explodes when vibrations from the bee’s abdomen and
thorax are transmitted to the flower’s anthers. The buzz is merely a by-product
of the vibrations.

King found that when a bee alights on a flower, it sends direct vibrations
into the anther, exerting a force 20 times greater than gravity. A force
of only 5 times that of gravity is needed to make the pollen explode.

King’s work was stimulated by the need of apple and kiwi fruit growers
to find cheaper and more efficient ways of gathering pollen artificially.
At present, pollen from kiwi fruit is collected by manually plucking male
flowers, dehydrating them, and then separating the pollen using screens.
Because the process is so involved, the end product costs between NZ $2000
and NZ $2500 a kilogram.

King is now developing a vibrating device to be connected to a vacuum
pollen suction tube which could help to gather pollen more easily and cheaply.

Because most of the land in the South Pacific consists of tiny islands,
research has been piecemeal. Conservation has been hampered by the isolation
of islands scattered across 25 million square kilometres of ocean. The conservation
strategy was endorsed by the International Council for Bird Preservation
at a scientific conference in New Zealand last month.

The region has the highest number of rare and endangered bird species
in the world per unit of land. Because many islands are so remote they can
often support only a few species of birds. But many of those species are
unique to one or two islands. Birds on islands are vulnerable to even the
smallest environmental disturbance. Introduced predators, such as rats,
cats, stoats, the Indian mongoose (in Fiji), and the brown tree snake (in
Guam), and the felling of native forests, hunting and disease have already
driven many species to extinction.

Rod Hay, a New Zealand scientist and one of the group that drew up the
strategy, says many species now need urgent attention. There is a serious
lack of information on the status and distribution of many species, and
resources to tackle the problems are scarce. A strategy for the whole area
will make it easier to judge priorities, and, with the backing of the ICBP,
it should be asier to attract funds from large donor agencies, such as the
World Wide Fund for Nature.

The strategy will be coordinated by the South Pacific Regional Environment
Programme, an intergovernmental agency. It will provide a blueprint for
conducting surveys and drawing together information on birdlife, suggesting
guidelines for managing species at risk. A key part of the strategy is the
establishment of a regional database for birds, which will be available
to researchers, managers and planners around the world. Hay is criticial
of ‘scientific raiders’ who come to the region for research and then go
home. He says the database will provide invaluable information to dedicated
workers in the region with limited access to scientific literature.

The working group has already drawn up a list of priorities. Forests
in Papua New Guinea, Vanuatu, New Caledonia, Fiji, Western Samoa and the
Solomon Islands are near the top of the list: estimates suggest that within
10 years all the trees that provide suitable habitats for birds will have
been felled. Seabird colonies, which are important as guides for local fishermen
in Kiribati, Tuvalu and French Polynesia, have also been targeted.

Individual species needing immediate action to save them include the
San Cristobal mountain rail, the toothbilled, Marquesas and Society islands
pigeons, the silktail and the Ponape mountain starling.

Meanwhile, the New Zealand government has come under pressure from the
ICBP to commit more staff and money to saving rare birds on the Chatham
Islands, off the east coast of the South Island. Ten of the 17 species of
birds there face extinction because of predation and loss of habitat.

The ozone layer above the Antartic was significantly depleted in the
mid-1960s, according to a New Zealand scientist who has studied preserved
samples of moss. He has measured the levels of ‘photo-protective’ substances,
which protect plants from harmful light, and which he says provide a novel
way of reconstructing the way in which stratospheric ozone fluctuated in
the past. The work may tell us whether ozone depletion is cyclical and whether
chlorofluorocarbons are the only factor in creating a hole.

Kenneth Markham, a chemist at the Department of Scientific and Industrial
Research (DSIR), funded by the New Zealand government, analysed samples
of the moss, Bryum argenteum. The samples, from the Ross Sea area, were
collected and preserved between 1957 and 1989. Markham looked for compounds
called flavonoids, which are common plant pigments (Bulletin de Liaison
du Groupe Polyphenois, vol 15, p 230).

Recent research has shown that flavonoids have an important photoprotective
function. The compounds are synthesised in plants when they are exposed
specifically to UV-B radiation, the range of wavelengths that is mostly
affected by the depletion of stratospheric ozone. Flavonoids are very sensitive
to small increases in UV-B radiation. Their concentration changes with the
level of UV-B in a linear fashion; that is, a doubling of the UV-B intensity
causes a doubling of the concentration of flavonoids, and so on.

Markham measured the flavonoid content of his moss samples. Results
confirmed the well-documented ozone hole of the 1980s.

Markham then examined ground-based measurements of ozone levels made
between 1964 and 1986 at the South Pole. He compared these measurements
with his plot of flavonoid levels over the same period and found that they
were ‘a near mirror image’ of each other.

According to Markham: ‘Even the unexpectedly high levels of UV-B irradiance
in the mid-1960s, which the flavonoid data indicate, appear to be mirrored
by a drop in ozone levels at this time.’ He says that, until now, the ‘intriguing
mid-1960s anomaly’ has received little recognition. Some recent theoretical
models have predicted that the ozone layer was significantly depleted at
about this time, and some early measurements support this.

Key factors in this mid-1960s depletion are believed to be tests of
nuclear bombs in the atmosphere and the low flux of particles from the Sun
which was associated with the mid-point of the 11-year sunspot cycle. Other
factors that may be important are ‘the quasi-biennial oscillation’ – ozone
is most badly depleted in alternate years – and emissions from the volcano
Agung, which erupted in the southern hemisphere in 1963.

Continuous records of ozone levels back to 1956 exist for just two sites
in Antarctica: the continental Halley Bay and Argentine Island. Data are
available from the South Pole from 1962 onwards and Syowa from 1966. Satellite
measurements have provided more comprehensive coverage, but only since the
late 1970s.

The analysis of flavonoid levels could provide data on trends in ozone
levels for different regions in Antarctica and elsewhere. According to Markham:
‘These plants offer some prospect of confirming whether the mid-1960s ozone
depletion occurred in other regions of Antarctica and of looking back beyond
1956 to see whether it happened in the past.’ If so, we have to re-examine
our understanding of why it is occurring. Maybe the chlorofluorocarbon theory
is over-simplistic.

The 22,000-hectare Waipoue State Forest in Northland, which boasts the
largest remaining group of native, coniferous kauri (Agathis australis),
has been ravaged by the leaf-eating marsupial. The worst affected tree is
the northern rate (Metrosideros robusta), a native of New Zealand that is
closely related to the Australian gum tree, a favourite food of possums.
A spokesman for the Department of Conservation, John Halkett, says that
15 to 20 per cent of the northern rate are seriously damaged. Also at risk
in coastal areas of the forest is the pohutukawa (Metrosideros tomentosa),
or New Zealand Christmas tree, which blooms at Christmas with a red flower.
An estimated 75 per cent of all trees in the Northland region, which runs
from Whangarei to North Cape, are damaged.

Pellets were due to be dropped this week over 18,000 hectares of the
threatened forest. Meanwhile, officials from the Department of Conservation
are negotiating with the Maori people, the Ngapuhi, to try to reach agreement
on airdrops of pellets over other areas to which they claim an ancestral
and spiritual connection.

The government recently allocated NZ$1.08 million (Pounds sterling 380,000)
for possum eradication, $700,000 of which is to be used in the Waipoue Forest.
The possum is a newcomer to Northland, having moved up from the south in
the 1970s. However, the number of possums has doubled in the past five years
to about 15 million. ‘Waipoue has particularly prominent international,
ecological and conservation values. Those values are currently being compromised
by the increasing possum numbers,’ said Halkett. In other parts of the country
dominated by possums, the creatures move to the next preferred species when
their diet of choice is exhausted. So the forest becomes progressively degraded.

Halkett says that if a significant proportion of the large canopy trees
are killed, the forest will dry out (because there is no barrier to upward
evaporation) and this will affect the ability of some species to regenerate.

Meanwhile, beef and dairy farmers have put pressure on the government
to spend more on controlling possums. Herds are at risk from possums carrying
tuberculosis. Possums spread the disease through droppings, urine or weeping
wounds. Cattle pick up the infection from grass contaminated by the possums.
They, in turn, can spread infection to humans through unpasteurised milk.
Officers of the Ministry of Agriculture and Fisheries check animals routinely,
and those which test positive are slaughtered. In 1988/89, 4829 cattle were
found to be infected with tuberculosis.

In a bid to entice trappers back into the bush, the Department of Conservation
last month decided to issue them with free permits to hunt possums on conservation
land. The price of pelts dropped to an average NS$3 each last season because
of the depression in the international fur market.

SCIENTISTS in Australia have developed a portable kit to sex animal embryos and split them to double their numbers – in a three-hour procedure that can take place on the farm. The technique, which supersedes laboratory methods that take two weeks, will simplify the breeding of cattle and other livestock.

Trials of the embryo-sexing technique in the laboratory and the field have shown it to be almost completely accurate. The method, developed by a team at the Australian National University (ANU) in Canberra, enables farmers and breeders to choose the sex of seven-day-old embryos quickly and easily, before they are transplanted into surrogate mothers. By splitting the embryo, the procedure should almost double the number of prime offspring. The kit can be used by a technician on the farm after minimal training, and sells for A$9500 (Pounds sterling 4800).

Top-quality breeding cows are first given hormones to make them produce as many as 20 ova, which are then fertilised by artificial insemination with semen from genetically superior bulls.

After seven days, the embryos are flushed from the cow’s oviduct or uterus by a technique known as lavage. The technician removes between four and 10 cells from the embryo for sexing. Using an assay technique known as the polymerase chain reaction, a segment of DNA in those cells is replicated continuously over two-and-half hours to make millions of copies. The team has developed a ‘single-tube reaction mix’ that combines the substances used for the test into one formula. If the test then reveals the DNA sequence of the Y chromosome, the embryo is male.

The researchers in Canberra have simplified embyro splitting so that it requires little skill. The embryo is held in place on an electrostatically charged plate and then split by a precise electronic micro-manipulator.

Once the sex of the embryo is determined, it can be split to produce twin embryos. These can then be transferred into separate surrogate mothers or frozen for future use. The researchers believe that this is the first time that embryos have been frozen before an analyst has sexed them. The team reports pregnancy rates of between 60 and 65 per cent for whole embryos and 55 to 60 per cent for those which have been split.

In stud animals, poor-quality sperm is a serious problem for the rural industry. Researchers have found that semen samples from bulls which have been fed compounds of grain mixed with steroids during winter contain 50 to 60 per cent dead cells. To overcome this problem, the Canberra group has developed a way to improve the quality of semen collected from stud animals for artificial insemination.

The technique is an adaptation of a process originally used on human semen, which separates dead from live sperm by selective filtration. The team has almost finished field trials for the process, which could also help breeding programmes for endangered species where low sperm counts are a problem because of inbreeding.

The research has produced a useful spin-off in the development of a new type of packaging for temperature-controlled storage of semen and embryos on farms. Three types of package have been developed: one which maintains a temperature of 17 Degree C for transporting semen; another which is constant at 38 Degree C and is suitable for storing embryos; and a third at -65 Degree C, which is suitable for transporting perishables.

A further development is a simple test to determine whether a piece of beef came from a male or female animal. While there are tests that determine the type of animal that meat has been taken from, this is the first test to determine its sex. The test, developed for the Australian Quarantine Inspection Service, has applications in the food-processing industry, which pays a higher price for bull meat because of its high water retention.

The technique uses cloned segments of DNA from the Y chromosome to determine whether identical samples are present in a meat sample.

The team’s research leader, molecular biologist Ken Reed, says the export potential for the new technologies is enormous, because of the important role artificial breeding plays in the US, Canada and many European countries. As well as boosting food production, the technology would be valuable to developing countries building up their livestock industries.

This work, the result of 10 years’ research at the ANU, led to the setting up of a company, Advanced Breeding Technology which merged with another company this year to form Advanced Riverina Holdings.

THE GEOLOGISTS who dated the oldest rocks ever found (This Week, 14 October) used an instrument that was designed for them by the Australian National University’s Research School of Earth Sciences. The design team is continuing to upgrade its Sensitive High Mass-resolution Ion Microprobe (SHRIMP) to achieve even higher resolutions.

SHRIMP determines the history of a rock by measuring the tiny amounts of lead formed by the decay of uranium trapped in minerals, such as zircons, at the time of crystallisation. The amount of uranium that decays to lead indicates how long ago the crystallisation process occurred.

The instrument can analyse more accurately than other microprobes a specimen’s chemicals and the isotopic content of its less abundant elements. The specimens of crystal are prepared as thin polished sections. SHRIMP bombards selected areas with a 10 000-volt beam of negative oxygen ions, drilling a shallow hole. The atoms and molecules are ejected from the hole as a beam of ions. This beam is transferred to a mass spectrometer for identification and counting of the ions.

The instrument’s large size enables it to transmit a wide beam of ions off the target. It can also refocus the beam so that the spectrometer can separate the different species of ions more efficiently.

A unique feature of SHRIMP is its7-tonne magnet with a turning radius of one metre; other machines use magnets weighing only a few kilograms, with a turning radius of about 30 centimetres. The geologists can switch the instrument quickly from one magnetic field to another to distinguish the mass of a species of ions from that of another. They have overcome the delay in switching magnetic fields by cutting the magnet into a series of slices, each insulated from the next, so that it effectively works as a number of magnets. This enables the magnet to settle to the nominated field within two seconds. The speed of the changeover permits closer monitoring of the composition of a sample as it changes.

Measurements on some 50 grains of zircon from the gneiss rocks found in Canada showed them to be 3.962 billion years old, with a margin of error of only three million years. The samples of gneiss were collected by the American geologist Samuel Bowring at Washington University in St Louis.

Bowring’s earlier analysis of the zircons indicated they might have grown in two or more widely-spaced time periods, obscuring their exact age. The ion microprobe was built to tackle this sort of problem.

SHRIMP’s construction was originally advocated in 1973 by Bill Compston, a geochemist at the ANU, on the grounds that ion microprobes then commercially available were insufficiently sensitive for such work. It took five years to build.

The existing SHRIMP can analyse crystals as small as 25 thousandths of a millimetre across. The team at the ANU is now building a new version that will be able to analyse areas down to 10 thousandths of a millimetre across and will use ion beams of caesium as well as oxygen. Refined features in the new instrument will give higher sensitivity and improved resolution. It will cost between $1.5 and $2 million.

The instrument will be a prototype for a commercial model to be marketed by the ANU’s commercial arm, ANUTECH. It will focus the ion beam to ensure that the area being drilled by ions is eroded uniformly. This will enable researchers to gather more accurate information from the analysis of holes drilled progressively down from the surface of a sample. The university has applied for a patent for the new system.

The ANU team is also redesigning the lens which directs the ions off the target, to improve the efficiency of ion extraction. The magnet has been substantially redesigned to make it faster and more controllable. Tests show that it will probably switch between magnetic fields two to three times as quickly as the existing system.

The new system will have four magnetic field sensors rather than the one that the present instrument has. Instead of the existing semicircular shape, the new magnet will completely enclose the ion beam. This will prevent the magnetic forces at the fringes of the magnet from affecting it. Fibre optic cables will be used to control the power supply. The revamped SHRIMP is expected to be in use by next September.

SCIENTISTS at the Australian National University (ANU) in Canberra have developed artificial eyes that ‘see’ the way that flying insects do. Like many insects, they use the cues provided by the apparent motion of the object to determine its direction and range. This work could lead to the development of unobtrusive visual aids for blind people as well as in robotics and the space and military industries.

The Australian team believes that its approach could help overcome some of the problems that have plagued the development of artificial systems which attempt to simulate human stereo vision.

Adrian Horridge, director of the ANU’s centre for visual sciences, says it is presumptuous to try to copy human perception for a mobile device. ‘Natural visual systems have evolved along economical and obviously effective lines and if we want to make a mobile robot that sees we would be quite satisfied if early models perform as well as insects,’ he says.

‘Insects with their comparatively simple eyes and tiny brains are quite capable of navigating, chasing mates or prey and escaping from danger. If you want the performance of a fly, copy the principles from a fly.’

Unlike human beings, insects are unable to use binocular vision to judge range. Research has shown that the bee and possibly other flying insects use the apparent motion of an image across the retina to gauge its range in the same way that we can effectively see objects in three dimensions with one eye shut by moving the head.

Knowing its own speed and the apparent velocity of the object, the bee gauges the object’s distance. Experiments have shown that the bee can also measure angular velocity, and therefore distance, irrespective of the structure of its surroundings.

These findings formed the basis for two devices. One model, a hand-held scanning device, has an eye built from the lens of a microscope and a charge-coupled device (CCD), a light-sensitive electronic chip.

A line of 128 pixels 1.6 millimetres long detects boundaries between light and dark objects. As the scene is scanned by moving the device at a steady rate from side to side, closer objects move across the field faster than more distant objects.

Using a theoretical model of the perception of motion, called the gradient model, a computer calculates the velocity for each point in the scene by measuring changes in the intensity of light at each angle. This gives the range of objects in each direction.

The device then converts the velocities into stereo tones, creating an aural space in which the motion of objects is effectively heard. Nearer objects pass across the aural space faster, and with a higher tone frequency, than more distant objects. Alternatively, it could be used to produce tactile sensations to describe the scene.

The second device using five photodetectors gives high resolution in a field of view of about 2 to 3 degrees over a range of 1 to 5 metres. It can pick up a small object such as a pencil at a distance of 2 metres.

This system uses angular and spatial gradients, detected by the five elements, to calculate the range of objects. The device does not have to be scanned; it simulates motion by essentially combining five snapshots simultaneously and producing a weighted sum of the outputs. Like the first device, it encodes the distance of the object through an audio amplifier as the pitch of a note.

Both devices, says the team, have advantages over conventional ultrasonic devices which are prone to giving ambiguous range readings because of reflection of the sound beam, and their resolution copes poorly with small objects. The scanning device gives the user or robot a panoramic view, picking out a series of objects at different ranges in each direction. It can also locate objects at very close range.

The five-detector camera has a narrower field of view but can detect immediate hazards in the direction it points.

While two devices have been patented, the technology needs refining and the devices miniaturised so that they can then be worn like a watch or a ring. The research has just received financial backing from the Japanese computer company Fujitsu.

Using instruments at Siding Spring Observatory and the Parkes radio
telescope in New South Wales, the scientists set out to investigate the
‘Great Attractor’, a huge concentration of mass into which the Milky Way
and neighbouring galaxies are falling at about 1000 kilometres a second
(91av, Science, 20 May).

The Great Attractor, which lies deep in the southern sky in the direction
of the constellation of Centaurus, but far beyond, was described in 1988
by a group of American and British astronomers. The phenomenon seemed to
be caused by a spherical concentration of mass, equivalent to about half
a million galaxies, situated about 150 million light years away.

The Australian astronomers, led by Don Mathewson of the Australian National
University in Canberra, say they now have evidence to suggest that the Great
Attractor has the shape not of a sphere but of a cylinder, some 240 million
light years long, and that the mass and the enormous gravitational force
it exerts resemble a moving loop of cosmic string.

According to cosmological theory, cosmic strings were created in the
second after the big bang and preserve its ‘superhot’ environment, in which
the forces of nature were united into a single superforce. Cosmic strings
are invisible; they have no ends and they wriggle violently through outer
space at almost the speed of light, forming loops that exert enormous gravitational
force. The strings are thin, yet have a mass of a hundred million billion
tonnes per centimetre.

Mathewson says that because the Great Attractor is situated in the southern
sky, the team was able to build up a large amount of data on it, and so
succeeded in measuring the peculiar velocities of galaxies beyond the Great
Attractor that are falling back into its mass. (Peculiar velocity is the
difference between the velocity of a galaxy and the velocity it should have
if the expansion of the Universe were uniform.) This breakthrough provided
proof of the Great Attractor’s existence and enabled the astronomers to
pinpoint its location. The team was also able to determine variations in
the velocities of the galaxies according to their distance from the attracting
region.

The research also showed that all the galaxies studied were flowing
towards the Great Attractor; none was observed that could be identified
with the attracting mass itself. In other words, the mass is invisible.
Together, these discoveries led the group to conclude that the Great Attractor
is a vast loop of cosmic string.

If scientists were able to identify cosmic strings, they could then
test the Grand Unified Theories that try to identify the single force from
which all known forces were born.

The team is now investigating the gravitational lensing properties of
the loop. Mathewson believes that the loop could betray its presence by
bending light from galaxies beyond it and deflecting the light so that it
reaches Earth by two different paths.

A search for lookalike galaxies, separated by about 20 seconds of arc,
or for galaxies with a sharp truncated edge, is now under way. Researchers
are using images from a survey by the UK Schmidt Telescope in the region
where the astronomers suspect the loop of cosmic string lies.

As the loop oscillates, like a violin string, it should produce gravitational
waves. This radiation is too weak to affect existing gravitational wave
‘telescopes’ but instruments now planned should be able to pick it up.