Category Archives: Uncategorized

Map of all nuclear test sites – 2000 tests in all

Between 1945 and 2008 more than 2000 nuclear test detonations were conducted.

Amazing. More than 2000 nuclear weapons have been detonated on Earth!

This map (click through for the map) shows the locations of all the test sites. Click on each icon to read more about the site and how many tests were conducted there.

The four test sites related to Africa and South Africa interested me.

  • Seems like South Africa collaborated with Israel in testing a nuclear weapon in 1979 south-east of our coast.
  • The Americans conducted secret test detonations just 1800km from Cape Town in 1958 as part of Operation Argus
  • The French conducted 14 nuclear tests in Algeria during the early 60’s

African nuclear test sites

Analysis of Human Development Index for South Africa

The UN’s Human Development Index is an attempt to quantify quality of life. Three measures are used to create a single human development score:

  • Health (life expectancy)
  • Education (adult literacy)
  • Wealth (GDP per capita)

Using only three variables makes comparison possible, but it does mean that the HDI is pretty crude.

It still makes interesting reading.

The latest report (with data for 2007) has just been released. Norway comes out on top followed closely by Australia.

South Africa comes in at 129th of the 183 countries (some really bad places like Somalia and Zimbabwe don’t have enough data to be on the list at all).

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I was particularly interested in the trends over time. South Africa has gained ground since 1980 but has fallen off since a peak in 1990.

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Looking at each of the components in HDI it becomes clear that life expectancy is hurting South Africa’s HDI score. AIDS is really holding us back. GDP per capita has also been pretty flat.

hdi-south-africa-components

How has South Africa done relative to similar countries? Let’s compare SA to the 26 countries with the closest HDI scores back in 2000.

Not pretty. As you can see we’ve been in free fall. We went from the middle of this little group to stone last!

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What about similar countries by geography? Let’s compare SA to our regional neighbors. Clearly our region is struggling, but SA has still lost two places!

hda-south-africa-regional

Computer program generates realistic image from freehand drawings

Believe it or not a computer program called PhotoSketch generated the image on the right.  Based on the freehand drawing and labels on the left!

This is pretty amazing stuff.

photosketch-1

The program processes the input image and searches tagged images for the required components. It can then seamlessly combine the components into an output image.

This is a very early version of the technology and some of the output images aren’t great. But it is still very impressive (project page has more examples).

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Strange ship off Sea Point – Petrobras 10000

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This ship has been sitting off Sea Point for a couple of days.

It has an unusual structure and looks like a large building at night. I was curious so when I managed to see the name this morning I did some research.

According to Rigzone (there is a site for everything) it is a drillship on the way to explore possible deep sea oil fields off Angola.

A drillship is a bit like a very mobile oil rig. They are used for exploring deep sea oil fields because they can move around far faster than a normal oil rig.

Drillships use dynamic positioning systems to stay exactly stationary while drilling. Using a combination of GPS, wind and motion sensors and a sophisticated computer model the ship can stay absolutely stationary while drilling. Pretty cool stuff.

Why are humans (mostly) hairless?

Most of us are (mostly) hairless. That is very unusual among mammals and pretty much unique among primates.

Why have humans evolved this trait? This New Scientist article outlines some of theories offered over the years.

We still don’t have a conclusive answer.

Theory 1: Avoiding the heat

Perhaps hairlessness made us better running hunters?As humans became savanna hunters body hair was shed to avoid overheating during long runs.

I have blogged before about theories suggesting that the human combination of hairlessness and profuse sweating allows for persistence hunting.

The problem:

Why has no other mammal adopted this strategy?

Many other mammals would benefit from better cooling systems and they all have fur – what is so different about us? Fur actually insulates against heat and the sun as well as keeping us warm in the cold.

Theory 2: Side-effect of big brains

This theory suggests that nakedness is a side effect of growing larger brains. It was noted that:

  • Human brains grow very rapidly just before birth
  • Humans retain characteristics of juvenile apes (flatter faces, bigger heads and eyes and naked skin).

The idea is that the stage just before birth has been protracted to allow the brain to grow even larger.

The problem:

If having hair were an advantage then we would just grow hair later in life. For example, we grow teeth even though we aren’t born with teeth.

Theory 3: No ticks here

Another theory is that we lost our hair in order to avoid ticks and other parasites.

The problem:

Why only us? If this were really an advantage other mammals would have evolved the same thing.

Theory 4: Aquatic ape

Humans are hairless and have a thin layer of fat under their skin. Sounds like whales and dolphins right?

The idea is that our evolutionary ancestors went through a stage evolving in aquatic environments. This could also help to describe why we walk upright.

By otters have thick fur...The problems:

There are many problems with this theory (read about them on Wikipedia). For example, humans can’t hold their breath very well and are not efficient swimmers.

Most importantly, hairlessness is only an advantage in fully aquatic species like dolphins and whales. Even full time swimmers like otters and seals have thick fur and swim superbly. In short, the aquatic ape theory doesn’t work all that well…

The world’s biggest fire extinguisher – a 747

747 fire fighting plane

Wired has this article about a 747 that has been converted for fighting fires. Sounds like a joke, but this is real.

A company spent $50 million converting a 747 into a fire fighting aircraft. It can drop 75,000 litres of flame retardant on fires. That compares very favorably with the 4,500 litres that the normal fire drop planes can carry.

Size isn’t the only innovation. Normal air drops on fires rely on gravity to expel the water for fire retardant. That means you get one drop and then have to go back for more.

This bad boy has a special pressurized system that allows for several drops. That helps when you’re carrying such a huge payload.

The major disadvantage of course is that this monster isn’t as nimble or flexible as the smaller aircraft and helicopters.

Growing a garden on a vertical wall

Wired has this photo gallery showing the work of botanist Patrick Blanc who specialises in covering walls with gardens. I always loved the look of ivy covered walls at university but this guy takes it to a whole new level.

Over the years he has perfected a special frame which allows plants to grow on vertical walls. Some of the wall gardens are the size of several tennis courts.

They look great. I love the way he has clearly planted different plans in sections to create patters.

Patrick Blanc's wall gardens

Patrick Blanc's wall gardens

Referees: They’re not perfect

Any sports fan knows that referees are as human as the rest of us – mistakes do creep in.

However, I recently read this short article citing studies that show ref’s also make more subtle, but systematic mistakes.

Home Crowd Advantage

This article discusses a study of 3500 Bundesliga matches that found measurable bias in favor of the home team:

  • Interestingly the bias was more significant when there was no running track around the field – in other words when the fans were closer to the ref.
  • Refs were shown footage of tackles with the sound on and the sound off. Those watching with the sound on ruled in favor of the home team 15.5% more often!

The Team in Red

In the past I have read that football teams wearing red win slightly more matches. This article discusses a study of tae kwon do referees found that they favor the fighter in red.

In tae kwon do one fighter has a red helmet and one has a blue helmet.

In the experiment 42 experienced refs were shown videos of sparring rounds.

  • The red fighters were awarded on average 13% more points
  • The videos were then digitally altered to switch the color of the helmets. Suddenly the points awarded flipped over with the new reds getting a bigger share.

Ninja bugs

National Geographic has a photo gallery showing off some of nature’s clever disguises. Well worth a look.

There are two bugs in this picture. Seriously.

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“Leaf knockoffs down to brown spots and notched edges, two Mimetica katydids with twiglike legs can rest or feed without drawing attention”.

In case you’re still not sure, here they are:

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The gallery is well worth looking at. Below are a few more of by favorites.

Not a snake…

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Finally, this is a great mantis. Nature is awesome.

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