New Plastic Degrades In Just Three Hours

Plastic is a globally important product; its versatility means you’ll find it in everything from electronics to furniture, prosthetic limbs to vehicles. There’s no doubt that it plays a big part in society. But on the flip side—it’s an environmental disaster. Because it degrades slowly, it accumulates in landfills for hundreds of years and can gradually leach harmful chemicals that make their way into groundwater. It also builds up in our oceans and can harm or kill marine animals. Furthermore, burning or melting it can release toxic emissions into the air.

There is therefore a need for plastics that don’t linger in the environment, which is what scientists from North Dakota State University have been working towards developing. Now, they’ve managed to come up with a plastic that breaks down upon exposure to light, and remarkably, it takes just three hours to fully degrade.

To fabricate their new material, they concocted a solution of molecules derived from fructose, a simple sugar found in foods such as fruit, and light-absorbing molecules called phototriggers. By heating this mixture, the scientists were able to create long, repeating chains of small molecules that formed a solid plastic when cooled.

Next, they exposed the plastic to UV light at a wavelength of 350 nanometers, which is within the range of wavelengths that the sun emits. This caused the light-absorbing molecules to break off from the chains of molecules, which triggered the plastic to start to degrade. The process was so efficient that in this proof-of-concept experiment, it took just three hours of exposure to UV light for the plastic to break down into a clear solution, indicating that the plastic had been reduced to its soluble building-block molecules.

According to the team’s recently published paper in Angewandte Chemie, these molecules can then be recovered and re-used to make new plastic, which helps reduce the demand for raw materials.

Obviously, we don’t want our garden furniture to start melting as soon as it’s outside, so this plastic isn’t practical for many applications. However, it would be very useful in electronic gadgets that are notoriously difficult to recycle and are continuing to cause serious waste problems.

The researchers are hopeful that with further development, their plastic can eventually be commercialized, but first they need to work out whether the phototriggers influence certain properties of the plastic, such as durability.

[Via Science, Angewandte Chemie]

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Why invest in the Baja California Real Estate market

Why invest in the Baja California Real Estate market

Real Estate market of Baja California, Mexico has gone through some important changes since the United States financial crisis of 2007–2009. Mexico and the United States have always been close economically tied neighbors. There is an old saying: “when America sneezes Mexico gets a cold” that holds some true in it. However this has proven to be a great opportunity for some economic areas of Baja California and the whole country. Mexican authorities have been doing a very good job, by improving many infrastructures like highways, roads and airports to take care of the new challenges envisioned. Continue reading

Baja as a great place to retire, in Mexico

Baja has a lot and enormous amount to offer retirees. Baja’s pace of life is ideal for retirement—you can relax, and still lead an active retirement. Stress levels are insignificant here.

The infrastructure is good in developed areas, and the areas you are likely to choose from are as safe as any modern town or city in your home country (in fact, Mexico has extremely tight firearms and lethal knife laws—making it statistically safer than many cities in the USA, for example).

The food is wonderful. Fresh fruit and vegetables, meats and fish are available at the local markets, and you’ll get great value for your money.  Food is also less expensive in Baja California, although prices and quality vary throughout the year, depending on the season. The variety of vegetables is also immense, including local kinds such as nopales (cactus) and chayotes. Mexico is also the home of the avocado and is the world’s biggest producer of the fruit.

Good healthcare is widely available. Baja California has great doctors, dentists, hospitals and other medical specialists. There are a range of insurance services available for you to buy to safeguard you and your dependants from the cost of private medical bills.

Your retirement income can go further in Baja California. Exactly how far will depend on your lifestyle expectations. Basic foods and drink are considerably less expensive in Mexico than they are in Europe and most places in the USA and Canada. Eating out can be less expensive too, and extremely good value for money.

If your retirement income is generated in hard currency, you will find your earnings stretch further on the basics needed for everyday living than it would in Europe, the US or Canada, for example.

Addiotionally to all this, if you consider de proximity towards the United States, Baja Californi is the ideal place to choose if you plan to retire in peace, and with all the confort available.
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Rock Art

Baja California Rock Art Dated to 7,500 Years Ago

Rock Art

Baja California Rock Art

The giant rock art murals that grace the walls of hundreds of shelters and caves  found in the hardscrabble hills of the high sierra in Baja California Sur, Mexico, date back as far as 7,500 years ago, according to data from an ongoing study of the area.

The ancient dates for the paintings cast little light on the mystery of who made them and why, but it suggests that whoever the painters were they came well before the Aztecs established their culture in central Mexico in the 12th century A.D.

“Once we did the dating and got to know how old they are, we were surprised by their antiquity because they look so fresh, so well preserved,” said Alan Watchman, a geoscientist and Australian Research Fellow at the Australian National University in Canberra and co-leader of the study team.

The paintings are of giant humans and animals, mostly done in red and black but also in white and yellow. The human figures are static, but the animals bound in herd-like movement across the rock-wall canvases.

Harry Crosby, an author and Baja California rock art expert in La Jolla, California, suggests that the paintings might represent a sense of “us and them” with the humans painted to depict how they dealt with each other in a static manner but with the animals as “food on the hoof.”

“The vision would be of the animals getting out of there and when [the painters] picture them one could argue they are trying to set up a kind of hunting magic,” he said, but added that it is difficult to know what they were thinking if we don’t even know who they were.

Mystery Painters

The murals had previously never been dated and even today little is known about the people who created them or what they were meant to communicate. Watchman and his colleagues are conducting a multi-year project to put the paintings in cultural context.

The team, which is partially funded by the National Geographic Society’s Committee for Research and Exploration, is working in the Sierra de Guadalupe. The murals are found in shelters that hang within spectacularly steep and pristine canyons.

Before the team started work in 2001, about 90 rock art sites were known in the Sierra de Guadalupe. Since then, the team has documented more than 320 additional sites. Hundreds more sites are known from the Sierra de San Francisco, which lies to the north.

Now that preliminary dates for the paintings are established, the team is searching for a site they can excavate for other materials to substantiate the dates of the art and help tell the story of who the painters were, how they used the landscape, and how they traveled.

“We are trying to put all that information together, but it is an arduous task,” said Watchman, who is collaborating with Lucero Gutierrez, an archaeologist with Mexico’s National Institute of Anthropology and History and Marisabel Hernandez Llosas, an archaeologist with the National Council of Science and Technology of Argentina.

Crosby said that until archaeologists are able to substantiate the rock art dates with other well-dated materials the mystery of the painters will remain. “There hasn’t been enough archaeology done yet and not enough dating for anybody to finger some group that was known to be on the peninsula at that time,” he said. “We simply have not got enough information to do that.”

Eliminating Dates

Crosby began exploring the region in 1967 and first published The Cave Paintings of Baja California: Discovering the Great Murals of an Unknown People in 1975. A second edition of the book was published in 1997.

He said the dates by Watchman and colleagues confirm his belief that the painters were not Cochimi, a group of native peoples who were present in the region when Jesuit missionaries from Spain arrived at the end of the 17th century.

Missionaries who were familiar with the paintings confirm this belief in their journals where they write of asking the Cochimi about the paintings and being told a widespread tale that the paintings were done by a race of giant people long past.

But the tales did not faze the late Clement Meighan, an anthropologist from the University of California at Los Angeles who in 1962 radiocarbon-dated a wooden peg recovered from one of the rock art sites as approximately 550 years old, which he used as an indicator to date the paintings to the time of the Cochimi.

But when Crosby looks at the murals he cannot imagine them as being so young.

“The vast majority of them are painted on volcanic agglomerate; it is a volcanic material that literally agglomerates from non-basaltic rock. It isn’t flows of lava, it is beds of material like pumice and ash that over a period of millions of years have agglomerated into surprisingly hard material,” he said.

Knowing the geology of the painting surface is important, added Crosby, to understand the pace at which the paintings deteriorate. Volcanic agglomeration, he said, breaks down over thousands of years owing to the subtle expansion and contraction forces caused by humidity and drying.

“A lot of these rock art sites have over-painting,” said Crosby. “One figure is painted on top of another. In some places they have as many as five layers.”

The newer layers are quite fresh appearing and visible, but the older layers are so degraded that they have almost disappeared. To Crosby this suggests that many years must have passed between the first painting and the last.

“These are older than Clement Meighan and others have suggested,” he said. “There is no other way to account for that kind of difference between the oldest and newest paints.”

Watchman, who is a specialist in rock art dating, obtained his dates from painted samples collected in 2001. More than 30 samples have been dated so far and several of them are at least 5,000 years old. Some go back 7,500 years, suggesting a painting culture that lasted for millennia.

“It says something about the continuity of culture over a long period of time,” he said.

Rock Art Conservation

Further studies in the years to come may resolve the mystery of who painted the murals, for what reasons, and how they vary through space and time. In the meantime, the researchers believe their recent discoveries warrant protection.

In 1993, the United Nations Education, Scientific, and Cultural Organization recognized the well-documented rock art murals in the nearby Sierra de San Francisco as a World Heritage site.

The research team is asking that the boundaries of this site be extended south to include the rock art in the Sierra de Guadalupe so that it can be properly protected and preserved for future generations.

“What we are trying to do is make them aware that there are many more sites in the sierra and that this is a rare set of paintings and an environmental situation that requires protection,” said Watchman.

Crosby believes that the remoteness of the sites affords them ample protection and that environmental and conservation organizations have already succeeded in educating the local populations that it is economically advantageous to preserve the paintings.

“The process of surface degradation is going to continue,” he said. “But that is a slow process. Five hundred years from now we’d find the paintings relatively little changed.”

John Roach
for National Geographic News
July 17, 2003
California Sea Lion

California Sea Lion

As of 2001, the population was about 175,000. California sea lions have increased 3 to 4-fold since the 1970s due to limitations placed on killing and harassment by the United States and Mexico.

California Sea Lion

Ways to identify this species:

Adult males are dark brown to black with a sagittal crest, tuft of hair on their head. Males have a robust chest, shoulders and neck, and a slender hind end. They lack the well-developed mane typical of other sea lion species. Females and juveniles are tan to yellow-ish and slender in form. Males are larger than females weighing up to 1,000 pounds and 220 pounds, respectively.

Biology

  • California sea lions breed at the Channel Islands off southern California, and at islands around the northern Pacific coast and along the east coast of Baja California.
  • California sea lions have nine pairs of teeth in the upper jaw and eight pairs in the lower jaw that enable them to feed on a diverse diet including northern anchovy, market squid, sardines, Pacific and jack mackerel, and rockfish. Males of populations in northern California use the mouths of rivers and streams to catch lampreys, salmon and eels. They also enjoy stealing fish from commercial and sport nets.
  • These sea lions are agile swimmers and can dive to depths from 245-1,760 feet depending on the season.
  • Males have more than one reproductive partner at the same time. They compete for females using physical displays, vocalizations and sometimes combat.
  • After giving birth, females remain ashore with their pups for 7 to 10 days before they return to sea to forage. A two to five-day routine of foraging at sea and nursing ashore continues until 6 months when pups are usually abruptly weaned.
  • Females usually live to 20-30 years of age and males do not live quite as long.

Threats

  • California sea lions have two main predators; the Great white shark and the killer whale.
  • Natural events such as El Niño, exacerbated in recent years by global warming, can result in pup and juvenile moralities and declines in pup births.
  • Human-related threats include entanglement in fishing gear and toxic impacts from pesticides.

Source: http://www.greenpeace.org/usa/en/campaigns/oceans/wildlife-facts/california-sea-lion/Image