Rubber Trees

Posted on May 26, 2013  Comments (5)

I think rubber trees are pretty cool, dripping out nice latex is just neat.

photo of rubber trees

Photo of rubber trees in Khao Lak, Thailand

Latex is collected from trees which is then treated to make rubber. Hevea brasiliensis (originally found the Amazon basin in Brazil), the Pará rubber tree, sharinga tree, or, most commonly, the rubber tree, is a tree belonging to the family Euphorbiaceae. Gutta-percha (Palaquium) is a genus of tropical trees native to Southeast Asia. The milky latex extracted from the trees is the primary source of natural rubber. Now refining petroleum is an alternative way for creating products that required rubber previously, but rubber is still economically important.

In 1876, Henry Wickham gathered thousands of para rubber tree seeds from Brazil, and these were germinated in Kew Gardens, England. The seedlings were then sent to India, Ceylon (Sri Lanka), Indonesia, Singapore and British Malaya (now Malaysia). Malaya was later to become the biggest producer of rubber. In the early 1900s, the Congo, Liberia and Nigeria also became significant producers of natural rubber latex.

photo of a rubber tree seed

Rubber tree seed from near Fraser’s Hill, Malaysia, by John Hunter.

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Webcast: Examining the Scientific Basis Around Exercise and Diet Claims

Posted on May 19, 2013  Comments (1)

Tim Noakes is the Director of UCT/MRC Research Unit for Exercise Science and Sports Medicine, Department of Human Biology, Faculty of Health Science, University of Cape Town and Professor, Discovery Health Chair of Exercise and Sports Science, University of Cape Town.

Tim examines some questions on science and exercise and health in the webcast. He shows the problem with drinking too much during exercise and the correlation of hospital admissions correlated to the sport drinks marketing and changing of the official drinking guidelines. He also discusses the outdated ideas related to lactic acid and muscles.

He is currently studying the science of food and human health and is skeptical of low fat health claims: “No evidence that dietary fat is related to heath disease.” He is certainly more knowledgable than I but I would still be cautious of completely accepting that premise. It does seem to me there is lots of evidence that claims of causation between eating a high fat diet and heart disease were too strong (many other factors were critical – such as weight, exercise, genetics, unsaturated fat v. saturated fat…).

Tim Noaks: “50% of what we teach is wrong; the problem is we don’t know which 50% it is. Our job as educated people is to spend our lifetime trying to figure out which 50% is which. Until it is disproven accept that for which the evidence appears solid and logical and is free of covert or overt conflicts of interest, because unfortunately industry is driving what you believe in many many things. But don’t ever dismis lightly that for which there is credible evidence… and there is such clear evidence the diets we are eating are horrendous.”

As I have said before, scientific literacy is critical to allow us to make those judgements about what is credible evidence and what are outright lies, foolish claims or highly suspicious claims tainted by conflicts of interest.

Related: Can You Effectively Burn Calories by Drinking Cold Water? – Static Stretching Decreases Muscle Strength – Lack of Physical Activity Leads to 5.3 Million Early Deaths a Year – Science Continues to Explore Causes of Weight Gain – Study Finds Obesity as Teen as Deadly as Smoking

Clay Water Filters for Ghana

Posted on May 13, 2013  Comments (5)

Pure Home Water, Ghana manufactures and distributes AfriClay Filters in an effort to bring clean water to 1 million people. So far they have delivered filters to provide 100,000 people clean water.

The process is simple. Water is placed in a clay filter and gravity pulls the water through the pores left in the clay during firing.

Sediment and bacteria are filtered out in several ways:

  • Physical straining: the particles are too large to fit through the pores in the clay
  • Sedimentation or adsorption: particles come to rest on or stick to the clay
  • Inertia: friction in the pores keeps the particles from passing through

Bacteria are also killed by a coating of colloidal silver (a disinfectant), which we apply to all filters that pass our quality control tests. While sediment and bacteria are filtered out, the molecules of water are small enough to pass through the pores in the clay.

The filters are sold to those who will use them. The effort has shown a willingness to pay by villagers in remote Northern Ghana (those earning < US$1/day). I imagine (I am just guessing) the prices are subsidized; in the last decade more (most?) appropriate technology solutions will have those benefiting pay something for the benefits they receive.

My nephews are working on a similar effort in India, using bio sand filters, I plan to post more on that later. There is current a campaign to help fund the delivery of water filters to Indian villages.

Related: Solar Powered Water Jug to Purify Drinking Water – Electric Wind – Student Invents Solar-Powered Fridge – Reducing Poverty

Europe Bans Certain Pesticides, USA Just Keeps Looking, Bees Keep Dying

Posted on May 9, 2013  Comments (1)

For years the bee colony collapse disorder has been showing the difficulty of the scientific inquiry process. And that difficulty often becomes more difficult if interests with lots of money at stake want to block certain conclusions.

One-Third of U.S. Honeybee Colonies Died Last Winter, Threatening Food Supply

Multiple factors — pesticides, fungicides, parasites, viruses and malnutrition — are believed to cause the losses, which were officially announced today by a consortium of academic researchers, beekeepers and Department of Agriculture scientists.

“We’re getting closer and closer to the point where we don’t have enough bees in this country to meet pollination demands,” said entomologist Dennis vanEngelstorp of the University of Maryland, who led the survey documenting the declines.

Beekeepers lost 31 percent of their colonies in late 2012 and early 2013, roughly double what’s considered acceptable attrition through natural causes. The losses are in keeping with rates documented since 2006, when beekeeper concerns prompted the first nationwide survey of honeybee health. Hopes raised by drop in rates of loss to 22 percent in 2011-2012 were wiped out by the new numbers.
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Most losses reported in the latest survey, however, don’t actually fit the CCD profile. And though CCD is largely undocumented in western Europe, honeybee losses there have also been dramatic. In fact, CCD seems to be declining, even as total losses mount. The honeybees are simply dying.

“Even if CCD went away, we’d still have tremendous losses,” said entomologist Diana Cox-Foster at Pennsylvania State University. “CCD losses are like the straw that breaks the camel’s back. The system has many other issues.”

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Given Tablets but No Teachers, Kids Teach Themselves – Having Never Seen Advanced Technology Before

Posted on May 3, 2013  Comments (5)

In a repetition of an experiment I have posted about here on the Curious Cat Science and Engineering Blog before (Letting Children Learn – Hole in the Wall Computers): Given Tablets but No Teachers, Ethiopian Children Teach Themselves

The experiment is being done in two isolated rural villages with about 20 first-grade-aged children each, about 50 miles from Addis Ababa. One village is called Wonchi, on the rim of a volcanic crater at 11,000 feet; the other is called Wolonchete, in the Great Rift Valley. Children there had never previously seen printed materials, road signs, or even packaging that had words on them, Negroponte said.

Earlier this year, OLPC workers dropped off closed boxes containing the tablets, taped shut, with no instruction. “I thought the kids would play with the boxes. Within four minutes, one kid not only opened the box, found the on-off switch … powered it up. Within five days, they were using 47 apps per child, per day. Within two weeks, they were singing ABC songs in the village, and within five months, they had hacked Android,” Negroponte said. “Some idiot in our organization or in the Media Lab had disabled the camera, and they figured out the camera, and had hacked Android.”

Nicholas Negroponte has tendency to overstate the fact from what I remember. I don’t think what he claims as “hacking Android” here is what a real scientist would claim as than is a write up of the results of the experiment. He could well mean they updated a setting or some similar thing. It is a shame to mislead when the bare facts are so cool. And possibly he isn’t misleading – I just am worried he is.

Also what does 47 apps per day mean? I can’t understand how you can usefully (including entertainment do that in any sensible way) – I doubt I use 15 applications in a month and I use the computer hours every single day. Makes me worry that “using” is not a very enlightening piece of data – instead just trying to make it seem like using 47 must mean they are engaged; it seems more likely to me to mean they are not used successfully so they have to go try something else or they are counting “used” in ways we wouldn’t.

Once a week, a technician visits the villages and swaps out memory cards so that researchers can study how the machines were actually used.

These kinds of experiments are very cool. They show how intrinsically curious we are are. Sadly our schools often beat the curiosity out of kids instead of engaging it.

Related: What Kids can Learn (look at the same idea in 2006) – Providing Computer to Remote Students in Nepal (2009) – $100 Laptops for the World