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Pesticide-Free Method Takes a Bite out of Mosquito-Borne Disease?

Scientists have modeled a system that may be used to control mosquitoes and the diseases they transmit, without the use of pesticides. In the proposed system, mosquitoes are engineered to carry two genes. The first gene causes males to transmit a toxin to females through their semen. The second gene, when expressed in females, makes them immune to this toxin. This research, published in the February 2011 issue of Genetics, describes a system that can be created using currently available molecular tools and could confine the spread of mosquitoes to isolated populations. It also allows the genes to be recalled if necessary.

"I hope that the results of this theoretical study will inspire molecular biologists to explore new ways of driving transgenes into populations," said John M. Marshall, Ph.D., a researcher involved in the work from the Department of Infectious Disease Epidemiology, School of Public Health at the Imperial College of London in the United Kingdom. "Ultimately, I hope that the application of these ideas will help move transgenic mosquito technology forward, and thereby contribute to the many efforts to reduce the prevalence of malaria and dengue fever in disease-endemic countries."

The gene transfer system was modeled using mathematical equations that describe how genetic alterations in the mosquitos' DNA are inherited from one generation to the next, and predict how these alterations will either spread or be eliminated from the population. The system has two basic components -- a toxin expressed in the semen of transgenic males that either kills female recipients or renders them infertile, and an antidote expressed in females that protects them from the effects of the toxin. An all-male release should result in population suppression because wild females that mate with transgenic males produce no offspring. A release that includes transgenic females propagates the desired gene because females carrying the toxin gene are favored at high population frequencies.

The scientists used simple population genetics models to explore the utility of this gene-transfer system, and found that it can work under a wide range of conditions. It requires a high frequency of gene transfer, which is desirable because it means that genetically altered insects released accidentally are unlikely to persist in the wild. Furthermore, it means that those released intentionally can be spatially confined and that the altered genes can be removed from a population through sustained release of wild-type insects. The scientists found few technical barriers to implementing this system, increasing prospects for engineering and testing in the coming years.

"Mosquito bites can mean more than an itchy annoyance," said Mark Johnston, Editor-in-Chief of the journal GENETICS. "For far too many people, they can lead to life-threatening diseases. But mosquitoes play a role in the greater ecosystem, and completely eradicating them may have unintended consequences that could be worse than the diseases they carry. This study is exciting because it suggests a way to control mosquito populations without pesticides, and in a way that gives us control of the process."

How severe can climate change become?

How severe can climate change become in a warming world? Worse than anything we've seen in written history, according to results of a study recently appearing in the journal Science.

An international team of scientists led by Curt Stager of Paul Smith's College, New York, has compiled four dozen paleoclimate records from sediment cores in Lake Tanganyika and other locations in Africa.

The records show that one of the most widespread and intense droughts of the last 50,000 years or more struck Africa and Southern Asia 17,000 to 16,000 years ago.

Between 18,000 and 15,000 years ago, large amounts of ice and meltwater entered the North Atlantic Ocean, causing regional cooling but also major drought in the tropics, says Paul Filmer, program director in the National Science Foundation's (NSF) Division of Earth Sciences, which funded the research along with NSF's Division of Atmospheric and Geospace Sciences and its Division of Ocean Sciences.

"The height of this time period coincided with one of the most extreme megadroughts of the last 50,000 years in the Afro-Asian monsoon region with potentially serious consequences for the Paleolithic humans that lived there at the time," says Filmer.

The "H1 megadrought," as it's known, was one of the most severe climate trials ever faced by anatomically modern humans.

Africa's Lake Victoria, now the world's largest tropical lake, dried out, as did Lake Tana in Ethiopia, and Lake Van in Turkey.

The Nile, Congo and other major rivers shriveled, and Asian summer monsoons weakened or failed from China to the Mediterranean, meaning the monsoon season carried little or no rainwater.

What caused the megadrought remains a mystery, but its timing suggests a link to Heinrich Event 1 (or "H1"), a massive surge of icebergs and meltwater into the North Atlantic at the close of the last ice age.

Previous studies had implicated southward drift of the tropical rain belt as a localized cause, but the broad geographic coverage in this study paints a more nuanced picture.

"If southward drift were the only cause," says Stager, lead author of the Science paper, "we'd have found evidence of wetting farther south. But the megadrought hit equatorial and southeastern Africa as well, so the rain belt didn't just move--it also weakened."

Climate models have yet to simulate the full scope of the event.

The lack of a complete explanation opens the question of whether an extreme megadrought could strike again as the world warms and de-ices further.

"There's much less ice left to collapse into the North Atlantic now," Stager says, "so I'd be surprised if it could all happen again--at least on such a huge scale."

Given what such a catastrophic megadrought could do to today's most densely populated regions of the globe, Stager hopes he's right.

Stager also holds an adjunct position at the Climate Change Institute, University of Maine, Orono.

Co-authors of the paper are David Ryves of Loughborough University in the United Kingdom; Brian Chase of the Institut des Sciences de l'Evolution de Montpellier in France and the Department of Archaeology, University of Bergen, Norway; and Francesco Pausata of the Geophysical Institute, University of Bergen, Norway

Trapped Sunlight Cleans Water

High energy costs are one drawback of making clean water from waste effluents. According to an article in the journalBiomicrofluidics, which is published by the American Institute of Physics, a new system that combines two different technologies proposes to break down contaminants using the cheapest possible energy source, sunlight. Microfluidics -- transporting water through tiny channels -- and photocatalysis -- using light to break down impurities -- come together in the science of optofluidics.
The researchers fabricated a planar microfluidic reactor, or microreactor, which is essentially a rectangular chamber made of two glass plates coated with titanium dioxide, the active ingredient in many sunscreen lotions. On exposure to sunlight, the coating releases electrons that react with contaminants in the water and break them down into harmless substances. This is the photocatalysis part of the process. The high surface area of the microreactor enhances the ability of the catalyst to capture sunlight. Although the gap between plates is small, Zhang plans to expand the rectangular dimensions to two square meters. "Our current small-scale proves the concept but we are also scaling up the reactor to a throughput of 1,000 liter per hour," he says. If the larger reactor proves effective, many parallel devices might be used to handle industrial water treatment applications.

Why Some Plants Flower in Spring, Autumn and Some in Summer

A team of researchers from Warwick have isolated a gene responsible for regulating the expression of CONSTANS, an important inducer of flowering, in Arabidopsis.

'Being able to understand and ultimately control seasonal flowering will enable more predictable flowering, better scheduling and reduced wastage of crops', explained Dr Jackson.

Whilst the relationship between CONSTANS and flowering time in response to day length is well established, the mechanism controlling the expression of CONSTANS is still not fully understood.

The scientists present their work at the Society for Experimental Biology Annual Meeting in Prague.

Many plants control when they flower to coincide with particular seasons by responding to the length of the day, a process known as photoperiodism. A flowering mutant of Arabidopsis, which had an altered response to photoperiod, was used in the study led by Dr Stephen Jackson.

In the study funded by the BBSRC, the team identified the defective gene in the mutant plant that caused its abnormal flowering time.

They then cloned a working version of the gene, known as DAY NEUTRAL FLOWERING (DNF), from a normal Arabidopsisplant and introduced it into the mutant plant to restore its normal flowering response to day length.

The role of DNF in normal plant flowering is to regulate the CONSTANS gene. CONSTANS is activated only in the light and the plant is triggered to flower when CONSTANS levels rise above a certain threshold level during the daytime.

In normal plants, DNF represses the levels of CONSTANS until the day length is long enough and conditions are favourable for the survival of their seedlings. In mutant plants without an active DNF gene, CONSTANS is not repressed and they are able to flower earlier in the year, when days are still short.

The presence of the DNF gene has not yet been identified in species other than Arabidopsis but the scientists believe their on-going work may prove to have a wider significance for other species.

Scientists can override complex pathways that control flowering by artificially inducing or inhibiting key flowering genes such as DNF and CONSTANS. This can already be done in the laboratory by spraying an 'inducing agent' onto plants, stimulating them to flower early.

This could be used to extend the length of the harvesting season or to co-ordinate flowering or fruit production to a specific time. Growers already regulate the flowering of a few plants such as Chrysanthemum and Poinsettia, the latter specifically for Christmas and Easter.

Unravelling the complex pathways that control plant flowering will help scientists to understand and influence flowering patterns more effectively and in many different species.

Plankton the key to the Origin of Earth's first breathable atmosphere?

Researchers studying the origin of Earth's first breathable atmosphere have zeroed in on the major role played by some very unassuming creatures: plankton.

In a paper to appear in the online Early Edition of the Proceedings of the National Academy of Sciences(PNAS), Ohio State University researcher Matthew Saltzman and his colleagues show how plankton provided a critical link between the atmosphere and chemical isotopes stored in rocks 500 million years ago.

This work builds on the team's earlier discovery that upheavals in Earth's crust initiated a kind of reverse-greenhouse effect 500 million years ago that cooled the world's oceans, spawned giant plankton blooms, and sent a burst of oxygen into the atmosphere.

The new study has revealed details as to how oxygen came to vanish from Earth's ancient atmosphere during the Cambrian Period, only to return at higher levels than ever before.

It also hints at how, after mass extinctions, the returning oxygen allowed enormous amounts of new life to flourish.

Saltzman and his team were able to quantify how much oxygen was released into the atmosphere at the time, and directly link the amount of sulfur in the ancient oceans with atmospheric oxygen and carbon dioxide.

The result is a clearer picture of life on Earth in a time of extreme turmoil.

"We know that oxygen levels in the ocean dropped dramatically [a condition called anoxia] during the Cambrian, and that coincides with the time of a global extinction," said Saltzman, associate professor of earth sciences at Ohio State.

In a paper in the journal Nature just last month, the same researchers presented the first geochemical evidence that the anoxia spread even to the world's shallow waters.

"We still don't know why the anoxia spread all over the world. We may never know," Saltzman said. "But there have been many other extinction events in Earth's history, and with the exception of those caused by meteor impacts, others likely share elements of this one -- changes in the balance of oxygen and carbon dioxide in the atmosphere and oceans."

"By getting a handle on what was happening back then, we may improve our understanding of what's happening to the atmosphere now."

Something enabled oxygen to re-enter the oceans and the atmosphere 500 million years ago, and the study suggests that the tiny plant and animal life forms known as plankton were key.

Plankton may be at the bottom our food chain today, but back then, they ruled the planet. There was no life on land at all. And aside from an abundance of trilobites, life in the oceans was not very diverse.

Not diverse, that is, until a geologic event that scientists call the Steptoean Positive Carbon Isotope Excursion (SPICE) occurred. In previous work, Saltzman and his collaborators showed that the SPICE event was caused by the burial of huge quantities of organic matter in ocean sediments, which pulled carbon dioxide from the atmosphere and released oxygen.

The more oxygen plankton encounter in their cells, the more selective they become for the light isotope of carbon in carbon dioxide, and absorb it into their bodies.

By studying isotopes in fossilized plankton contained in rocks found in the central United States, the Australian outback, and China, the researchers determined that the SPICE event happened around the same time as an explosion of plankton diversity known as the "plankton revolution."

"The amount of oxygen rebounded, and so did the diversity of life," Saltzman explained.

Other researchers have tried to gauge how much oxygen was in the air during the Cambrian, but their estimates have varied widely, from a few percent to as much as 15-20 percent.

If the higher estimates were correct, then the SPICE event would have boosted oxygen content to greater than 30 percent -- or almost 50 percent richer than today's standard of 21 percent.

This study has provided a new perspective on the matter.

"We were able to bring together independent lines of evidence that showed that if the total oxygen content was around 5-10 percent before the SPICE, then it rose to just above modern levels for the first time after the SPICE," Saltzman said.

The study has some relevance to modern geoengineering. Scientists have begun to investigate what we can do to forestall climate change, and altering the chemistry of the oceans could help remove carbon dioxide and restore balance to the atmosphere. The ancient and humble plankton would be a necessary part of that equation, he added.

"When it comes to ancient life, they don't sound as exciting as dinosaurs, but the plankton are critical to this story."

Saltzman's coauthors on the PNAS paper include Seth Young of Indiana University; Lee Kump of Pennsylvania State University; Benjamin Gill of the University of California, Riverside, and Harvard University; Timothy Lyons, also of the University of California, Riverside; and Bruce Runnegar of the University of California, Los Angeles. Additional coauthors on the Nature paper included Andrew Knoll of Harvard University.

The National Science Foundation's Geobiology and Low-

Tourists can now rent mobile phones from leading South African network

TOURMED Policy Holders can now take advantage
of this exclusive Vodashop Rentafone offer from
South Africa's leading cellular network.

• Only Rentafone is conveniently located at all major South African airports.
• Free Daily Phone Rental - Mandatory daily Theft and Damage Protection (TDP) fee of
  R9-95 applicable.
• Calls up 50% less than International calls from most leading hotels.
• Save more than 35% on roaming call charges.
• Free incoming calls in South Africa.
• Free Voicemail calls in South Africa.
• Free itemised billing via e-mail.
• Free emergency calls to 112.
• Enjoy the Free Vodacom 'call me service' when renting more than one phone from Rentafone.

This special low rate is only applicable with the purchase of a TOURMED Travel Medical Insurance Policy.

Further special offers to this exclusive deal are:

• GPRS or GSM data service is available for travelers or delegates who require 24 hour Internet access.
• Satellite phones are available for rental for areas that are not yet covered by the network.
• Local Sim Card only service available for travelers using their own handset.
  

Call Charges

• Calls to locations within South Africa are charged at the low rate of R2.40 per minute.
• Calls are up to 30% cheaper than pre-paid. Nod need to look for airtime recharge cards.
• Special service calls or calls to other networks will cost more.
  

Payment and Billing

A R1 000.00 authorisation fee is taken from the client's credit card as a security deposit. Itemised billing will be dispatched via e-mail within 72 hours after the hired phone has been returned. This may take longer for roaming calls.

Phones may be returned to any Vodashop Rentafone; Cellucity store; Hire4Lower offices or at any of the following South African airports: Johannesburg, Cape Town, Durban, Bloemfontein,East London, George and Port Elizabeth.

In South Africa, concierge service via mobile phone rental

The virtual ink had barely dried on our recent story about AtYourSide in Shanghai when word reached us of another personal guide service, again with an event-driven angle: Africa Talking, a South African concierge service that's ideally positioned to benefit from all the visitors to next month's World Cup.

Africa Talking is a 24/7 concierge service for visitors to South Africa with dedicated travel, entertainment and emergency assistance. Upon arrival at any South African international airport, members receive a free Nokia 1208 mobile phone, complete with an Africa Talking SIM card and talktime. They can then use that phone during the course of their stay for help planning and arranging travel and entertainment throughout the country. Directions, rentals, tickets, reservations and all kinds of attraction advice are available from Africa Talking via its phones, which can be used for personal calls as well; in fact, users can save up to 70 percent of their roaming costs when they use their Africa Talking phone, the company says. In emergencies, meanwhile, the Africa Talking mobile phone serves as a tracking device that lets the Cape Town-based company immediately recognize users and see where they are, enabling it to quickly provide directions, dispatch a taxi or arrange emergency assistance. Last but not least, at the conclusion of any trip, users can drop off their used handsets at the airport; from there, they will be resold, with 50 percent of the proceeds going to a local South Africa charity. Membership in Africa Talking ranges from GBP 29 for a single trip to GBP 169 for multiple trips over the course of a year.

Concierge and guide services can make good sense at any time of year, of course—particularly for business travelers—but large, international events increase the potential demand many times over. Those in major host countries around the globe: one to emulate for the masses of visitors coming soon to an event near you...?

Hotel Introduces Superstrong Toilets, Able to Flush Golf Balls

Most people considering a hotel look at amenities such as swimming pools, spa services and gourmet restaurants -- not the power of the toilets.

However, a clogged-up toilet is the sort of thing that people talk about on the, er, back end, according to Richard Senechal, the senior vice president of facilities for Loews Hotels.

"Guests want a reliable toilet," he told AOL News. "You don't hear about that on the front end, but if there is a problem, you hear about it."

Apparently, clogged toilets are enough of a problem at hotels that Loews tried to eliminate any problems customers have with elimination by installing high-tech commodes capable of flushing 10 golf balls down the chute at once.

The problem was first noticed by Tony Rodrigues, the regional director of engineering for Loews Hotels at Universal Orlando.

He figured out that clogged toilets were affecting as many as 12 guests a day at the three hotels he worked at.

"The root of the problem was the mandated low-flow toilets, which clogged too often," Rodrigues said. "Often, the guest would clog a toilet and they would be embarrassed and delayed in their plans. In other instances, guests would use the restroom just before checking out and it was only after several hours of overflowing water before we discovered something was wrong."

Not wanting to leave customers down in the dumps about taking one, Rodrigues started looking for a toilet that would take a load off his engineers' backs.

That perfect pot -- or "bowly grail," if you will -- was found in something called the Champion 4, made by American Standard, a toilet so powerful it can supposedly flush 18 golf balls, 38 rubber tubes, 16 water wigglers and 40 feet of tissue without getting clogged.

According to James Walsh, American Standard's vice president and general manager of consumer fixtures, the Champion 4 proves that not all low-flow toilets do a crappy job.

"The first generation of low-flow toilets had such poor performance that they left many people under the impression they weren't, pardon the expression, worth a 'crap,' " said Walsh, whose knowledge of the inner workings of toilets has led some of his co-workers to call him "Professor Toilet."

American Standard Brands

James Walsh is so flush with knowledge about commodes that he's called "Professor Toilet." He says flushing pingpong balls is the best way to determine if a toilet has the proper flow.

Clogged toilets have increasingly been a problem ever since toilets were mandated to flow 1.6 gallons per minute from 3.5 gallons a minute about 15 years ago.

"Toilets in the U.S. work like siphons," Walsh said. "Once the toilet gets flowing, it pulls everything down. Early on in the days of low-flowing toilets, the only way to get the flow going was to reduce the size of the trap, which is the opening between the tank down into the pipe."

Walsh and company have eliminated the problem of clogs by increasing the size of the trap, or outlet; increasing the size of the flush valve from the standard 2 inches to 4; and changing the bowl design to get more flow going.

But how they test those toilets can make some people lose the lunch they lost when they went to the bathroom.

"We test toilets with miso paste," he said, describing a soy paste used in Japanese cooking that is close to the consistency of human defecation. "We use up to 400 grams [about 14 ounces] at one time, while the average amount of human waste I think is about 250 grams [8 ounces].

The miso paste is used in a variety of ways to simulate real human waste, which Walsh divides into three categories: sinkers, floaters and semi-floaters.

"We test it like this to figure out how to keep the bowl clean, because you don't want -- how should I put it? -- skid marks," he said.

Although various products, including corn cobs, pencil shavings and rubber tubes, are put into the pot, Walsh says pingpong balls are actually the best test of a toilet.

"Pingpong balls float, so if you can flush them, you know you have a good flow," he said.

But it was the golf balls that sold Loews on the Champion 4, and Senechal believes a good toilet flow can lead to a good cash flow.

American Standard Brands

The Champion 4 toilet made by American Standard is so powerful it can reportedly flush 18 golf balls at once.

The hotel chain usually only updates its plumbing every 10 to 12 years, but it was so flushed with excitement about the elimination of clogged toilets that it is starting to install the super-commodes in its 18 properties six years earlier than normal.

"Rodrigues was able to show a good return on investment, since the engineering staff time spent on unclogging toilets has been reduced by 80 percent," Senechal said.

Will other hotels get off the pot and start installing the toilets?

Barbara De Lollis, who covers business travel and writes the Hotel Check-In column for USA Today, thinks so -- to a point.

"People love to complain," she said. "If a hotel can reduce even one complaint, that's good. Now, it's not like it's a Heavenly bed, but it's a selling point."

There is one potential problem Senechal admits he's not excited about facing.

"I hope people don't bring buckets of golf balls to test out the toilets," he said. "So far, I haven't seen it."

Do you think this is a bit over the top? ... Have your say :-)