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  1. There are three living species of zebra: Grévy's zebra (Equus grevyi), the plains zebra (E. quagga), and the mountain zebra (E. zebra). Zebras share the genus Equus with horses and asses, the three groups being the only living members of the family Equidae. The skin of the zebra is black. The stripes are the result of differences in the concentration of melanin in the hairs - more melanin = black, less melanin = white. The differences in concentration can be explained by the concept of the Turing pattern. https://en.wikipedia.org/wiki/Turing_pattern . Sometimes this effect goes wrong and a zebra has a coat without stripes. In those cases the coat looks brownish, but may have feint stripes or small spots. Why does the zebra have stripes? Zebras suffer the scourge of flying, biting insects. Laboratory experiments have shown that alternating aras of black and white visually confuse these insects and they do not land on striped areas. Other experiments in which horses have been covered with striped horse rugs reduce the numbers of insects landing on the horse. (There's a commercial opening! Make horse rugs with a zebra pattern. I wonder if a checked or tartan pattern would work.)
    2 points
  2. We all know about the English mathematician, Alan Turing. He's the bloke who was very instrumental in developing a machine to decode German military messages created using Enigma machines. But what did he do after the war ended? Well he want back to being a mathematician working on developing computers. However, he must have got bored with that field of study. When Turing was 39 years old in 1951, he turned to mathematical biology, finally publishing his masterpiece "The Chemical Basis of Morphogenesis" in January 1952. "The Chemical Basis of Morphogenesis", which describes how patterns in nature, such as stripes and spots, can arise naturally and autonomously from a homogeneous, uniform state. https://en.wikipedia.org/wiki/Turing_pattern Turing proposed a model wherein two homogeneously distributed substances (P and S) interact to produce stable patterns during morphogenesis. These patterns represent regional differences in the concentrations of the two substances. Their interactions would produce an ordered structure out of random chaos. There's an explanation of this process in the attached video. Go to timestamp 3:18 It is interesting that the stripes of an individual zebra are unique to that zebra, in the same way as your fingerprints are unique to you. This individuality is also the basis of eye pattern recognition used in security systems.
    1 point
  3. There doesn't seem to be a lot of positives to celebrate lately.. So, here's one: (https://www.bournemouth-kawasaki.co.uk/2024-yamaha-r125/) Son just put a deposiut down on it. I test rode it and it certainly screamed more than a 125cc bike - the max xx(14.6bhp being max power) for a learner. Got it for a bargain and not quite what they advertised it for... and it is in mint condition... Watch out for the gripes thread as we go to insure it..
    1 point
  4. I emailed Spacey, Says he's well, but not wise. Says he can't log in at all. Didn't explain why.
    1 point
  5. This 1982 photo shows the Simpson Desert the driest I've ever seen it. The only vegetation visible from the air was the shrubs and trees, no grass to be seen. The drought broke the following year with a lot of flooding. The photo is taken from a Cherokee Six just entering the Simpson from the east en route from Windorah to Alice Springs. Everything went ok until halfway across when the alternator died and the battery went flat, so no radio or instruments, just the compass. We landed on the strip at Ringwood Station on the western edge of the desert, and luckily the station owner was home to see us come in. He drove over and picked up the pilot so he could use the station radio to call Alice Springs airport to clear a space for us to fly into there, being pre satellite days when the stations relied on HF radio for communications. We got to stay overnight in Alice waiting on the new alternator to be fitted, then on to Bililuna in W.A. the next day. Another surprise there on landing - the client (Shell if my memory is correct) had given the crew three days off as the Halls Creek annual races were on. We took off again to Halls Creek which took us straight past the Wolfe Creek crater, so that was a good sight from the air. It was a memorable trip for different reasons. When the battery went dead over the Simpson, it really got us thinking how little preparation we had in regard to survival gear if we had to put down in a dune corridor. We didn't even have near enough water required to stay on the ground any length of time. As a comparison of seasons, I took these photos with a digital compact camera in the Simpson in 2010 after an extended wet period. Most of the green you can see is grass and herbage that burns off with hot, dry conditions. It was very different to the other deserts I've been in which have more permanent vegetation in the dune corridors, and much more spinifex. Edit: Just as a post script, it wasn't far from where these three photos were taken that I came across an old survey marker peg that was the site of Geosurveys Base Camp #1 from Reg Spriggs' first motorised crossing of the desert in 1962.
    1 point
  6. There's a DIY kit for everything.....
    1 point
  7. Mary & Joseph were going to name him Jerry. Just as the scribe started to write, Mary stubbed her toe. Christmas Adam comes before Christmas Eve. Christmas Eve isn't happy.
    1 point
  8. Let's face it. The American Empire is in its terminal phases exacerbated by the mania of Trump. China does not need to conquer militarily. It has conquered commercially. The irony is that it applied the lessons taught by the American Dream. I also think that Russia is declining in importance. Putin is 73 years old. Just look at our thread where we advise of the passing of famous people. So many of those passing on are past their "three score and ten". Can Putin and his philosophy have long to last? The European Union is strengthening itself. At the moment it is spending some effort on military defence in response to Russia's activity, but at the same time is going ahead comercially. India is a growing commercial entity, but not a military one. Southeast Asia just wants to make money. The problem areas are Africa and the Middle East, but these areas are involved in localised tribal conflicts. None of the countries involved there have the ability to become world powers.
    1 point
  9. Were you a Juvenile Deniliquint red? A mate of mine was posted to the Primary school as Headmaster in 1959. Name of Jim Perrry. Nev
    1 point
  10. A random thought struck me when I woke up this morning. 2026 is the 70th anniversary of the Melbourne Olympic Games in 1956. I attended one day of those games on a school excursion from Deniliquin High School. I was 12 at the time, in Year 7. We went by bus from the school.
    1 point
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