Ancient brain shows how animals evolved heads

One of the oldest brains ever discovered is providing clues on how the world's first heads evolved.

The over 500-million-year-old brain, described in the latest issue of the journal Current Biology, suggests that rudimentary brains emerged before defined heads.

Defined heads likely emerged later to protect brains.

The ancient brain belonged to a crustacean called Odaria alata, which had a pair of large eyes on stalks. Scientists also often say that Odaria alata looked like a submarine. You can see the resemblance more in this video.

Javier Ortega-Hernández, who authored the study, determined that the eye-like features were connected to a hard, thin and flat body part called the "anterior sclerite." The connection was made possible via nerve endings originating from the front part of the brain.

"The anterior sclerite has been lost in modern arthropods (insects, spiders and crustaceans), as it most likely fused with other parts of the head during the evolutionary history of the group," says Ortega-Hernández, a postdoctoral researcher at the University of Cambridge.

For the study, he compared the remains of Odaria alata with another very ancient creature: a soft-bodied trilobite. Trilobites were marine creatures that were abundant during the Palaeozoic Era, 542-251 million years ago.

Ortega-Hernández next compared the creatures with anomalocaridids, a group of large swimming predators that lived at around the same time as the other studied species.

These larger organisms, like Odaria alata, were found to have a natural plate in the brain region.

"What we're seeing in these fossils," he says, "is one of the major transitional steps between soft-bodied worm-like creatures and arthropods with hard exoskeletons and jointed limbs - this is a period of crucial transformation."

The transformation occurred during what's known as the Cambrian Explosion, which was a period of rapid evolutionary innovation about 500 million years ago when most major animal groups emerge in the fossil record.

Prior to this period, the majority of animal life on Earth consisted of soft-bodied species that resembled algae and jellyfish. The Cambrian Explosion then led to creatures with hard external coverings (exoskeletons), defined heads and jointed limbs.

"Heads have become more complex over time," Ortega-Hernández says.

"But what we're seeing here is an answer to the question of how arthropods changed their bodies from soft to hard. It gives us an improved understanding of the origins and complex evolutionary history of this highly successful group." http://www.abc.net.au/science/articles/2015/05/08/4232198.htm

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No bags, thanks!!! Part 04

Recycle, Reuse, Reduce

Recycling your plastic shopping bags is one of the most obvious courses of action, however only 10% of Australian households take their plastic bags to a central collection point for recycling. This could be due to the fact that HDPE bags can not be put out for collection with other household recyclables, and there is no separate kerbside collection for them as the volume does not support the cost. Instead, bags must be taken to central recycling collection points, such as supermarkets, where there are special bins to collect the bags. Even at these central collection points there is a risk that the bags may end up unsuitable for recycling due to a range of contaminants such as LDPE bags, ink, food, even supermarket dockets if they are left in the bags.

Prior to recycling, of course, the aim should be to reuse your bags. According to the Australian Bureau of Statistics, less than 1% of plastic bags used in Australia are reused, however 82.6% of Australian households say that they reuse plastic bags. This list of possible uses for plastic shopping bags is almost as long as the lifespan of the bag itself!
If you don't want to take your bags back to the supermarket to use again next time you buy your groceries, there are a multitude of ways you can use them around the house, limited only by your imagination. One thing they should not be used for is lining garbage bins. It doesn't matter if you put them straight in your bin as waste or put your other garbage in them, the plastic bags will still end up in landfill, and potentially at large in the environment.

Given the costs and inconvenience associated with recycling, and the fact that reuse only delays the plastic entering the environment, the most sensible option is to cut down on the number of plastic bags that you use, or stop using them altogether. It is estimated that it takes the average Australian family four shopping trips to accumulate 60 plastic shopping bags. If everyone accepted one less plastic bag every time they went shopping, the number of bags used would be reduced substantially.

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Alternatives

There are a range of alternatives to plastic bags. Some retailers save the cardboard cartons that stock is packaged in, so customers can use them to pack their groceries. Others may offer paper bags. Some major supermarket chains have string or calico bags available for sale at a very small price. These bags can be kept in the car and used again and again. The advantage of calico bags is that they are stronger than the plastic bags, and also much easier to carry. It takes a little thought to get used to bringing your own bags, but it is an easy habit to fall into and it is such a relief not to have to pack the groceries away, and then find room to pack away the plastic bags as well!

There are of course situations where you can't beat a plastic shopping bag, such as when buying meat or "messy" items. Thankfully, technology is catching up with the need for a replacement for polythene bags. It was recently reported that supermarkets in Australia will introduce biodegradable bags made from tapioca starch in April 2003. These bags will look and feel like polythene bags but will decompose in three months.

So next time you go shopping, hold your head up proudly as you reuse or refuse a plastic bag. You may not be in a rubber dinghy chasing a whaling boat or pursuing ivory poachers, but you have made a contribution to the future of the planet.
http://www.abc.net.au/science/features/bags/default.htm

No bags, thanks!!! Part 03

Production of plastic bags

Plastic bags are made from ethylene, a gas that is produced as a by-product of oil, gas and coal production. Ethylene is made into polymers (chains of ethylene molecules) called polyethylene. This substance, also known as polyethene or polythene, is made into pellets which are used by plastic manufacturers to produce a range of items, including plastic bags.

You have probably noticed that there are two types of plastic shopping bags - the lighter, filmy bags you get from supermarkets and other food outlets, and the heavier bags you get from other retail outlets, like clothing stores. The supermarket bags are made from high density polyethylene (HDPE), while the thicker bags are made from low density polyethylene (LDPE). Unlike HDPE, LDPE can not be recycled.

While plastic bags may not be the most high tech application of plastics technology, it is certainly one of the most prevalent. According to Clean Up Australia, Australians use in excess of 6 billion plastic bags per year. If tied together these bags would form a chain that is long enough to go around the world 37 times. More than half of these bags (3.6 billion) are made from HDPE.

Management of plastic bag usage

With this number of plastic bags in circulation, it is of little surprise that plastic bags are a significant pollutant. On Clean Up Australia Day in 2002 nearly half a million plastic bags were collected.

Different countries have adopted a range of approaches to discourage the use of plastic bags in an attempt to cut down on the number of bags finding their way into the environment. In South Africa for instance, where an estimated eight billion plastic bags are used annually, the government has implemented new regulations that will see only thicker, more durable plastic bags produced. As well as making them more suitable for reuse, it is hoped that the extra cost associated with their production and supply will prevent retailers giving the higher quality bags away, making their use a more expensive option for consumers.

The use of plastic bags is being discouraged in other countries such as Singapore and Taiwan, while the tax imposed on the use of plastic shopping bags in Ireland has resulted in the use of plastic shopping bags being reduced by 90% in just six months. Prior to the 15 euro cent per bag tax, it was estimated that 1.2 million plastic shopping bags were being handed out in Ireland per year. The money raised from the tax will be used to fund environmental initiatives.

We'll have to wait and see if any of these measures will be adopted in Australia to address the problem here. In September 2002 federal Independent MP Peter Andren and Greens Senator Bob Brown introduced private member's bills into parliament that would put a 25 cent levy on plastic shopping bags, and direct the funds raised to an education program publicising the environmental costs of plastic bags in Australia. This bill was not passed, with the Minister for the Environment and Heritage Dr David Kemp preferring to explore voluntary options for plastic bag control, before imposing another tax on the Australian public.

One of the key voluntary options currently being trialed is the National Packaging Covenant, a self-regulatory agreement between government and industries in the packaging chain that was established in 1999. Over the five year period of the agreement, signatories will aim to minimise the environmental impacts of consumer packaging waste and develop sustainable recycling collection systems. To date there are over 500 signatories to the covenant, representing government, industry and business interests.

While Canberra decides on a national plan of action to reduce the problem of plastic bag pollution, it's easy to put a household action plan in place. http://www.abc.net.au/science/features/bags/default.htm

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No bags, thanks!!! Part 02

Production of plastic bags

Plastic bags are made from ethylene, a gas that is produced as a by-product of oil, gas and coal production. Ethylene is made into polymers (chains of ethylene molecules) called polyethylene. This substance, also known as polyethene or polythene, is made into pellets which are used by plastic manufacturers to produce a range of items, including plastic bags.

You have probably noticed that there are two types of plastic shopping bags - the lighter, filmy bags you get from supermarkets and other food outlets, and the heavier bags you get from other retail outlets, like clothing stores. The supermarket bags are made from high density polyethylene (HDPE), while the thicker bags are made from low density polyethylene (LDPE). Unlike HDPE, LDPE can not be recycled.

While plastic bags may not be the most high tech application of plastics technology, it is certainly one of the most prevalent. According to Clean Up Australia, Australians use in excess of 6 billion plastic bags per year. If tied together these bags would form a chain that is long enough to go around the world 37 times. More than half of these bags (3.6 billion) are made from HDPE.

Management of plastic bag usage

With this number of plastic bags in circulation, it is of little surprise that plastic bags are a significant pollutant. On Clean Up Australia Day in 2002 nearly half a million plastic bags were collected.

Different countries have adopted a range of approaches to discourage the use of plastic bags in an attempt to cut down on the number of bags finding their way into the environment. In South Africa for instance, where an estimated eight billion plastic bags are used annually, the government has implemented new regulations that will see only thicker, more durable plastic bags produced. As well as making them more suitable for reuse, it is hoped that the extra cost associated with their production and supply will prevent retailers giving the higher quality bags away, making their use a more expensive option for consumers.

The use of plastic bags is being discouraged in other countries such as Singapore and Taiwan, while the tax imposed on the use of plastic shopping bags in Ireland has resulted in the use of plastic shopping bags being reduced by 90% in just six months. Prior to the 15 euro cent per bag tax, it was estimated that 1.2 million plastic shopping bags were being handed out in Ireland per year. The money raised from the tax will be used to fund environmental initiatives.

We'll have to wait and see if any of these measures will be adopted in Australia to address the problem here. In September 2002 federal Independent MP Peter Andren and Greens Senator Bob Brown introduced private member's bills into parliament that would put a 25 cent levy on plastic shopping bags, and direct the funds raised to an education program publicising the environmental costs of plastic bags in Australia. This bill was not passed, with the Minister for the Environment and Heritage Dr David Kemp preferring to explore voluntary options for plastic bag control, before imposing another tax on the Australian public.

One of the key voluntary options currently being trialed is the National Packaging Covenant, a self-regulatory agreement between government and industries in the packaging chain that was established in 1999. Over the five year period of the agreement, signatories will aim to minimise the environmental impacts of consumer packaging waste and develop sustainable recycling collection systems. To date there are over 500 signatories to the covenant, representing government, industry and business interests.

While Canberra decides on a national plan of action to reduce the problem of plastic bag pollution, it's easy to put a household action plan in place.

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No bags, thanks!!! Part 01

With all due respect to Kermit the Frog, it's easy being green. Although we may be overwhelmed by the environmental catastrophes that seem to occur around us with alarming regularity, Karen Pearce says there is a simple way each and every person can make a difference. It doesn't involve travelling the world to clean up oil spills or standing in the path of bulldozers to prevent land clearing. It actually involves shopping …

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Plastic shopping bags and the environment

The environmental issues associated with plastic shopping bags have featured in the news in the last couple of months, following the apparent success of the plastic bag tax in Ireland in reducing the number of plastic shopping bags that are used in that country. While this approach has also been suggested for addressing the problem in Australia, the government will examine a number of options before deciding on a management plan. In the meantime, the best thing we can do for the environment is simply reuse, or better yet, refuse a plastic bag when we go shopping. Easy!

Plastic shopping bags have a surprisingly significant environmental impact for something so seemingly innocuous. As well as being an eyesore (next time you are outside, have a look around - you'll be amazed at the number of plastic bags littering our streets and waterways), plastic shopping bags kill large numbers of wildlife each year. In the water, plastic bags can be mistaken for jellyfish by wildlife. This makes plastic bag pollution in marine environments particularly dangerous, as birds, whales, seals and turtles ingest the bags then die from intestinal blockages. Disturbingly, it is claimed that plastic bags are the most common man-made item seen by sailors at sea.

The biggest problem with plastic bags is that they do not readily break down in the environment, with estimates for the time it takes them to decompose ranging from 20 to 1000 years. One of the disquieting facts stemming from this is that plastic bags can become serial killers. Once an animal that had ingested a plastic bag dies, it decays at a much faster rate than the bag. Once the animal has decomposed, the bag is released back into the environment more or less intact, ready to be eaten by another misguided organism. The incredibly slow rate of decay of plastic bags also means that each bag we use compounds the problem, because the bags simply accumulate.

Plastic bags also clog drains and waterways, threatening not only natural environments but also urban ones. In fact, plastic bags in drains were identified as major factors in the severe flooding in Bangladesh in 1988 and 1998. This has resulted in a ban on plastic bags being imposed there early in 2002.

On top of the significant environmental costs, widespread use of plastic bags is also costly in terms of dollars and cents. Apart from the price of the bags themselves, which is four to six cents each, a great deal of money goes into collecting the bags (ie cleaning up!) once they've been discarded.
http://www.abc.net.au/science/features/bags/default.htm

Tiny killer jellyfish born in a tank

A jellyfish with a deadly sting has been bred in captivity for the first time by Australian scientists, opening up the possibility of developing an antivenom.

The tiny box jellyfish, with a bell just 12 millimetres long, is responsible for Irukandji syndrome, a potentially fatal condition that attacks the central nervous system.

Researchers Heather Walling and Lisa-ann Gershwin from the CRC Reef Research Centre at James Cook University (JCU) in Townville announced their results this week.

The jellyfish, Carukia barnesi, had gone through a planktonic stage and were now attached to rocks on the floor of an aquarium at the Marine Aquaculture Research Facility Unit at JCU.

Irukandji jellyfish are found around the northern coast of Australia. And the species grown in captivity is one of nine to cause Irukandji syndrome, which killed two tourists in Australia in 2002.

Gershwin said Irunkandji syndrome began with a mild sting, like a mosquito bite. Within an hour, victims experienced severe lower back pain, shooting pains all over the body, cramping, nausea, vomiting, profuse sweating and coughing.

Depending on the species, loss of motor control and paralysis could follow, with some victims eventually dying of brain haemorrhages or heart failure.

Gershwin, who also works at the Australian Institute of Marine Science, said the deadly syndrome could be responsible for many more deaths not diagnosed at first.

"The significance of being able to breed these little guys is huge," said Gershwin.

Breeding the jellyfish was the first stage to developing an antivenom, she said, which required between 10,000 and 1,000,000 jellyfish.

She said developing an antivenom would involve extracting the toxin from the stinging cells, chopping the molecule up into "different bits" and testing different concentrations of those bits in animals.

Captive breeding also meant more jellyfish toxins were available for scientists to study potential pharmaceutical benefits, and could also allow for rapid diagnostic techniques for Irukandji stings.

"Because of the incredible potency of the toxins, the likelihood of being able to harvest useful chemicals is very high," said Gershwin.

"Researchers require reliable supplies of the jellyfish, which Mother Nature doesn't always provide. People are poised ready to pounce on the next available specimens."

Gershwin said she wasn't sure what defining factor had allowed them to breed the jellyfish successfully; she said it was "mostly luck". Many researchers had been trying to breed the jellyfish since the 2002 deaths.

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Clues to the nervous system

Dr Michael Corkeron from Townsville Hospital, a doctor who is developing a new treatment for the syndrome, said that a better understanding of its physiology would most likely lead to better ways to treat it.

Anything that affected the central nervous system like that might also help researchers understand how the nervous system worked, he said.

And perhaps scientists would find out whether the toxin held clues to mechanisms that could block particular effects on the system, Corkeron told ABC Science Online.

"You have to wonder if something so powerful holds some pharmaceutical benefits," he said.
http://www.abc.net.au/science/articles/2004/04/07/1082414.htm

Box jellyfish may be threat all year round

Children swimming off the coast of Australia's north should wear stinger suits all year round, after a little known species of box jellyfish was discovered near beaches during the supposedly safe season.

Suspected of belonging to the genus Chiropsalmus, the jellyfish is closely related to the deadly box jellyfish Chironex fleckeri. Although not lethal itself, stings by the new jellyfish do cause discomfort, and attack by several individuals could inflict serious poisoning in a child.

The December issue of the Australian Medical Journal reports that hundreds of the species have been netted at a beach in the Northern Territory town of Nhulunbuy, in Aboriginal lands of the Arhnem Land, between May and October - well outside the official stinger season.

Stinger season lasts from the October 1 to the June 1 each year, and swimmers are advised to avoid certain areas where they might be at risk of coming into contact with box jellyfish. There have been several anecdotal sightings of Chiropsalmus over the past 10 years, but this is the first time they have been netted in such numbers.

One of the authors, Professor Bart Currie from the Menzies School of Health Research at the Royal Darwin Hospital in the Northern Territory, said the appearance of the jellyfish in winter was unprecedented, and had implications for public health warnings.

"These jellyfish generally cause only mild pain and itching, but if several were to surround a child in the water, they could lead to a major envenoming," he wrote.

Currie said the better known and more deadly box jellyfish Chironex fleckeri has also been known to appear outside the official season. "There are deaths known from three of the four months between the end of the stinger season and the start of the next," he said.

Box jellyfish may also extend their range and season in the future, according to Currie. If global warming trends continue, we may see box jellyfish moving south and staying around for longer within the next 10 to 15 years, he added. http://www.abc.net.au/science/articles/2002/12/10/743824.htm

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How jellyfish avoid bumping into things

Box jellyfish might have 24 eyes but new research says they only use a few of them to avoid collisions.

Researchers say an Australian box jellyfish Chiropsella bronzie uses these eyes to help navigate around the seabed by detecting contrasts in light intensity.

Dr Anders Garm, from Lund University in Sweden, compared the jellyfish with another box jellyfish, Tripedalia cystophora, a native of Caribbean waters.

The research, presented at the Society of Experimental Biology's conference in Glasgow at the weekend, found that T. cystophora is better at avoiding obstacles than its Australian relative, a good thing given the Puerto Rican's mangrove habitat has more snags.

Each jellyfish has two sets of camera-type eyes with fish-like lenses, called the upper and lower lens eyes.

The researchers say the lower lenses help them avoid obstacles, after observing the animals didn't respond to objects above the water's surface.

They say the lower lenses can pick up changes in light intensity, and the greater this so-called intensity contrast, the better the jellyfish is at avoiding objects.

"Contrast is important because without contrast the object cannot be detected by any eye," Garm says.

"Obstacle avoidance is governed by intensity contrast which fits with our other data which strongly suggest that the jellyfish are, in fact, colour blind."

C. bronzie is the less-harmful relative of the deadly Australian box jellyfish Chironex fleckeri.

Sunset go-slow

Dr Jamie Seymour, director of the Tropical Australian Stinger Research Unit at James Cook University in Queensland, says when the Sun goes down the box jellyfish stop operating.

"For T. cystophora once the Sun disappears or the light shaft disappears the animal sinks to the bottom, for C. bronzie we're not too sure and for C. fleckeri the data suggests that they shut down and go catatonic; we suggest that they go to sleep."

But Seymour is most excited about the clues that the eyes of jellyfish, which have no brain and only a basic nervous system, could provide into the workings of more complex eyes.

"The simpler system the easier it is to understand, once you've got an understanding then you relay that on up the line," he says.http://www.abc.net.au/science/articles/2007/04/02/1883903.htm

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Should you use vinegar on all jellyfish stings? Does vinegar work for all jellyfish stings? And how does it work?

Everyone has a theory on the best treatment for jellyfish stings - vinegar, hot water, fresh water, urine, cold tea, warm beer.

Queensland experts advise that vinegar is best for jellyfish stings, but not all stingers should be treated the same way, says Dr Lisa-Ann Gershwin, director of the Australian Marine Stinger Advisory Service.

Vinegar works extremely well for box jellyfish and their tiny cousins the irukandji, found northwards along the coast from about where the Queensland town of Bundaberg sits, says Gershwin.

But vinegar should NOT be used for bluebottle stings, found further south along the beaches of eastern Australia. The official advice for bluebottle stings is to gently wash off the stingers with sea water and then immerse the area in hot water (no hotter than the rescuer can comfortably tolerate) for 20 minutes.

What happens when you're stung

We know of 2500 species of jellyfish, and all but one of them has the capacity to sting.

In most cases people don't feel the sting because the harpoon-like stinger can't penetrate the skin or can't penetrate deep enough to be a concern.

Gershwin says all jellyfish use the same delivery systems and triggers. These nematocysts are little capsules filled with coiled up harpoon-like barbs.

"Picture a knife serrated on both edges to help anchor it into its victims flesh when it fires. There's venom on both the inside and outside of the harpoon.

The capsule has a hair trigger, which is fired mechanically by touch. It can also be fired by changes in density or chemistry such as ph differences, or being exposed to fresh rather than salt water.

Although the mechanism is the same, toxins from different types of jellyfish work in different ways , which is why some jellyfish stings are more serious than others. Box jellyfish stings, for example, lock the heart in a contracted state.

"A box jellyfish sting is the worst imaginable pain, says Gershwin. "It is instantaneous and feels like boiling oil."

Irukandji stings, on the other hand, start out as a mild sting but then suddenly cascades 20 to 30 minutes after the sting into the potentally fatal irukandji syndrome - high blood pressure, vomiting, body spasms and profuse sweating.

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Vinegar and tropical stingers

Scientists still don't know why vinegar works for tropical stingers, says Gershwin

"We don't know exactly what's going on chemically, so as to why it works, it's a mystery."

"It's a fluke that we even found out, but it does work and it works better than anything else ever tested."

According to Gershwin vinegar somehow blocks the nematocysts or stinging cells ability to fire, "it happens instantaneously as soon as the vinegar is applied".

"It can't do anything about those that have already fired, but it stops any more from shooting off. In a typical sting you get maybe 10 per cent of nematocysts firing. But on a typical tentacle there will be many thousands that haven't fired off yet."

Rubbing the stingers or pouring fresh water on them, however, should be avoided, as this will cause the nematocysts to fire and make the sting much worse, says Gershwin.

"The last thing you want to do is increase your toxic load if you've already been stung."

Editor's note: since this article was published in 2011, research published in 2014 questions the use of vinegar on box jellyfish stings. The research, published in the journal Diving and Hyperbaric Medicine, suggests vinegar promotes further discharge of venom from already discharged nematocysts.

Hot water and bluebottles

Why hot water instead of vinegar should ease the pain of bluebottle stings is also a mystery, says Gershwin.

"It's the recommended treatment, but remember fresh water will cause nematocysts to fire. On the other hand you are dilating capillaries, forcing toxin to circulate which may be diluting the amount at the sting site.

"Claims hot water denatures the venom have been proven wrong" says Gershwin, "unless the water temperature is at least 60 degrees Celsius. And if you're putting water at that temperature on your skin, you've got bigger problems to deal with.

"In trials, hot water has done a better job than ice at relieving the pain. No one's really sure why, it's not a placebo effect, but it could be blocking pain pathways with another type of stimulus."

http://www.abc.net.au/science/articles/2011/12/13/3389985.htm

Researchers declare war on box jellyfish

Research is underway into better first aid treatment and an anti-venom for stings from one of Australia's box jellyfish species.

The jellyfish, commonly known as irukanji, is about two centimetres in diameter and is present in Australian tropical waters.

Its sting causes minor pain, followed by low back and leg cramps, nausea and possible abnormal heart rhythms.

The Australian Venom Research Unit at the University of Melbourne is working on an anti-venom, while Surf Lifesaving Queensland will trial different first aid treatments.

Peter Fenner, of Surf Lifesaving Australia, says there is no proven first aid treatment at present.

"Although it's a very minor sting, we get these severe symptoms starting half-an-hour later and if we were able to find a first aid treatment that prevented those symptoms or reduced them, it would be very beneficial," Dr Fenner said.

"Currently the treatment is just to pour vinegar on the area where the person has been stung, observe them for 45 minutes and if they develop these severe symptoms they'd be transferred to hospital."
http://www.abc.net.au/science/news/stories/s26233.htm

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'Jellyfish' flying machine keeps upright

Scientists have built the first ever flying machine that is capable of stable hovering simply by flapping its wings, using a movement similar to that of a swimming jellyfish.

The new form of "ornithopter" is reported in today's Journal of the Royal Society Interface.

Planes work pretty well to transport humans large distances across the planet, says lead author Dr Leif Ristroph, an applied mathematician from New York University.

But scientists are still trying to find the best design for small-scale autonomous flying machines that can manoeuvre around small crowded spaces.

Such machines are in demand for surveillance, monitoring and search and rescue.

"Any time you want a pair of eyes where it's not practical to have a human go, you could possibly use one of these flyers," says Ristroph.

One approach has been to build flying machines with wings that flap like an insect.

But, says Ristroph, insects require their brain to keep them upright during flight, and so such ornithopters require an onboard computer to do the same.

Ristroph wanted to design a flying machine that used flapping wings but would stay upright without requiring an onboard computer.

The design he came up with involves four distinct wings that are hinged at the top.

A motor at the top opens and closes the wings together at a rate of 20 times a second.

"The basic thing you want to do when you are flying is generate lift upwards," says Ristroph.

"If you open and close an umbrella in principle that will squirt air downwards and that will generate an upwards force."

"Our design is basically something similar," says Ristroph, who carried out the research with colleague Dr Stephen Childress.

Ristroph didn't realise until after that he had made something that moved like a jellyfish.

Of course a jellyfish doesn't have to generate lift to stay in one place like a flying machine does, but it does move upwards by expanding its bell to draw water in and then contracting to squirt it out.

Ristroph and Childress also found that having flexible rather than rigid wings improved the lift.

Most importantly, the researchers found that when the flying machine was tilted, it quickly became upright again.

"It's got an intrinsic stability," says Ristroph. "It's a property that insect-like motion doesn't have."

Ristroph says he and Childress still don't understand why their creation is self-stable.

"The centre of gravity location is very important but we're still in search of a good aerodynamic and mathematical model to explain this stability," says Ristroph. http://www.abc.net.au/science/articles/2014/01/15/3925459.htm

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88 stung at Hanauma Bay, more jellyfish reported in Waikiki, Ala Moana

Lifeguards reported 88 jellyfish stings at Hanauma Bay this morning, including a female patient who was taken to the hospital by ambulance in stable condition.

Paramedics also treated a man for a sting at about 9 a.m., but he declined to be taken to the hospital, according to an Emergency Services Department spokeswoman.

The city closed the Hanauma Bay beach at about 10:30 a.m. because of the jellyfish influx.

It’s the second time this week that the beach at the popular snorkeling attraction was closed because of jellyfish.

An assessment will be done to see whether the beach can be reopened Thursday. The visitor’s center, parking lot and upper lookout remained open to the public.

The city closed the beach at Hanuma Bay on Monday when about 40 people reported stings. Hanuama Bay is normally closed on Tuesdays.

This month’s jellyfish influx has been unusually severe.

Lifeguards reported that 31 people reported jellyfish stings in Waikiki today. They counted more than 1,000 jellyfish at Ala Moana and Waikiki beaches.

On Tuesday, Lifeguards said that 120 beach-goers were stung in Waikiki and 3 others stung at Ala Moana Beach Park.

Lifeguards counted 1,060 jellyfish on the beach in Waiki, 241 at Ala Moana and 125 at Pokai Bay on the Leeward Coast.

Those beaches remained open, however lifeguards posted jellyfish warning signs and verbally warned beach-goers to stay out of the water.

Jellyfish tend to come ashore on Oahu about 10 days after a full moon

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Golden Jellyfish

Beautiful, Golden Jellyfish Invading Fisher's Nets Is a New Species

Hundreds of golden jellyfish that clogged fishing nets off the coast of Venice, Italy, are in fact a new species, experts say.

Last fall, fishers in the Adriatic Sea (map) near Venice, Italy, pulled up nets full of hundreds of two-inch-wide (five centimeter), golden jellyfish. Having never seen the jellyfish before, the fishers sent pictures to researchers, who identified the beautiful interlopers as a new species.

About two or three new jellyfish species pop up every year, says Claudia Mills, a marine biologist at the University of Washington in Friday Harbor. However, finding such a conspicuous newcomer in a relatively shallow body of water close to shore is extremely rare, says Stefano Piraino, a jellyfish researcher at the Università del Salento in Lecce, Italy.

Piraino and his colleagues published their description of the new jellyfish—dubbed Pelagia benovici—this month in the journal Zootaxa.

The find comes as a surprise to scientists because the Adriatic Sea is one of the best studied bodies of water in the world. The fact that this jellyfish avoided detection until last year suggests that it is a fairly recent arrival, the study authors assert. This means that it's probably an invasive species, Piraino said in an email interview.

The Gulf of Venice in the Adriatic Sea is a hot spot for alien species introduction, he explains. Intense transcontinental shipping activity, as well as the aquaculture trade, provides plenty of opportunities for invasive species to set up shop. "We believe this species entered the Mediterranean Sea by ballast water transfer [by ships]," Piraino says.

Experts aren't sure where P. benovici comes from, but it's a good bet that it could be native to the Indian Ocean, says marine biologist Mills. It's an understudied part of the world known for a surprising amount of diversity in marine organisms.

Researchers are just starting to get to know P. benovici, and much work remains to be done. They aren't sure how painful its stings are, since many of the fishers who handled the jellyfish wore gloves. And they aren't sure what it eats, although closely related species are carnivores that eat fish eggs and larvae, as well as tiny crustaceans, says Piraino. Source

do jellyfish eat

"Immortal" Jellyfish

A potentially "immortal" jellyfish species that can age backward—the Benjamin Button of the deep—is silently invading the world's oceans, swarm by swarm, a recent study says.

Like the Brad Pitt movie character, the immortal jellyfish transforms from an adult back into a baby, but with an added bonus: Unlike Benjamin Button, the jellyfish can do it over and over again—though apparently only as an emergency measure.

About as wide as a human pinky nail when fully grown, the immortal jellyfish (scientific name: Turritopsis dohrnii) was discovered in the Mediterranean Sea in 1883. But its unique ability was not discovered until the 1990s.

How the Jellyfish Becomes "Immortal"

Turritopsis typically reproduces the old-fashioned way, by the meeting of free-floating sperm and eggs. And most of the time they die the old-fashioned way too.

But when starvation, physical damage, or other crises arise, "instead of sure death, [Turritopsis] transforms all of its existing cells into a younger state," said study author Maria Pia Miglietta, a researcher at Pennsylvania State University.

The jellyfish turns itself into a bloblike cyst, which then develops into a polyp colony, essentially the first stage in jellyfish life.

The jellyfish's cells are often completely transformed in the process. Muscle cells can become nerve cells or even sperm or eggs.

Through asexual reproduction, the resulting polyp colony can spawn hundreds of genetically identical jellyfish—near perfect copies of the original adult.

This unique approach to hardship may be helping Turritopsis swarms spread throughout the world's oceans, she added. Source

do jellyfish eat

Box jellyfish may be threat all year round

Children swimming off the coast of Australia's north should wear stinger suits all year round, after a little known species of box jellyfish was discovered near beaches during the supposedly safe season.

Suspected of belonging to the genus Chiropsalmus, the jellyfish is closely related to the deadly box jellyfish Chironex fleckeri. Although not lethal itself, stings by the new jellyfish do cause discomfort, and attack by several individuals could inflict serious poisoning in a child.

The December issue of the Australian Medical Journal reports that hundreds of the species have been netted at a beach in the Northern Territory town of Nhulunbuy, in Aboriginal lands of the Arhnem Land, between May and October - well outside the official stinger season.

Stinger season lasts from the October 1 to the June 1 each year, and swimmers are advised to avoid certain areas where they might be at risk of coming into contact with box jellyfish. There have been several anecdotal sightings of Chiropsalmus over the past 10 years, but this is the first time they have been netted in such numbers.

One of the authors, Professor Bart Currie from the Menzies School of Health Research at the Royal Darwin Hospital in the Northern Territory, said the appearance of the jellyfish in winter was unprecedented, and had implications for public health warnings.

"These jellyfish generally cause only mild pain and itching, but if several were to surround a child in the water, they could lead to a major envenoming," he wrote.

Currie said the better known and more deadly box jellyfish Chironex fleckeri has also been known to appear outside the official season. "There are deaths known from three of the four months between the end of the stinger season and the start of the next," he said.

Box jellyfish may also extend their range and season in the future, according to Currie. If global warming trends continue, we may see box jellyfish moving south and staying around for longer within the next 10 to 15 years, he added. Source

What do jellyfish eat?