Showing posts with label biology. Show all posts
Showing posts with label biology. Show all posts

Sunday, 26 April 2015

Skateboarding in Afghanistan, Gentoo Penguins and Knitting: Two Colour Star Stitch

Skateboarding in Afghanistan

Girls in Afghanistan aren't allowed to ride bicycles but they are allowed to skateboard. Through the organisation @stakeistan, girls can skateboard, try out other sports and even get an education.

Gentoo Penguins

While marking penguins in photos for Zooniverse's Penguin Watch, the Gentoo penguins all seemed to have two chicks.

I wasn't sure whether I was seeing things or whether that fluffy mass at the parent's feet was really two penguin chicks. Turns out they do have two chicks, and even though the eggs are laid four days apart, they hatch within 24 hours of each other.

Two Colour Star Stitch

This is a stitch I found at The Weekly Stitch.I found it quite quick and simple to work up, but I only used one colour. I've seen other stitches called star stitch so I'm wondering how to classify stitches so that I can keep track of what I have and haven't done.

Saturday, 25 April 2015

Penguins, Knitting: Garter Tab Cast On and Chevrons

Garter Tab Cast On

This is a cast-on which can be used for shawls which are worked from the top down. It consists of a few stitches knitted into a rectangle, and then picking up stitches from a side and the cast-on row of the rectangle.

Chevrons

This is a pattern on 2 (mod 14 stitches) over two rows, and can be worked in garter or stockinette stitch. For example, row 1 is purl and row two is knit 1, then (increase 1 on/around next stitch), then knit 4, [(decrease 2 over the next 4 stitches) knit 4, (increase 2 over the next 2 stitches), knit 4] repeating the stitches in [] until the last two stitches which are (increase 1 over last but one stitch), knit 1.

For a sample pattern and video see The Weekly Stitch.

This is my first attempt.

World Penguin Day

It's world penguin day. There are 14 million penguins in the Antartic, spread over eight species.

Monday, 20 April 2015

Tardigrades, The Command Key and Keyup, TypeScript Classes, Goats in Rwanda

1. Tardigrades

Tardigrades are tiny creatures, around 1mm long that can survive extreme conditions. Some were sent into space on a satellite and not only did many of them survive but they even had healthy young.

These remarkable creatures can survive in a dehydrated state of suspended animation and can even repair damaged DNA when they come out of it. Some of them can survive radiation, extreme heat and extreme cold.

3. TypeScript Classes

The following is a TypeScript class

class Something {
  thing: string;
  constructor (thing: string){
    this.thing = thing;  
  }
}
var something = new Something ('whatever');

which produces the JavaScript

var Something = (function () {
  function Something () {
    this.thing = thing;  
  }
  return Something;
})();

var something = new Something ('whatever');

However, there is a simpler version of the TypeScript that will give the same result.

class Something {
  constructor (private thing: string){  
  }
}
var something = new Something ('whatever');
You can also make it public, which again results in the same JavaScript.
class Something {
  constructor (public thing: string){  
  }
}
var something = new Something ('whatever');

Although the JavaScript is the same, TypeScript will catch errors related to the private field. Note that everything is public by default.

Hope and Inspiration

Goats in Rwanda

It's easy to get bogged down by all the bad news and negative things highlighted around us so I'm going to add a section on stories, blog posts, articles that I find bring hope. The first of these is an article about a family in Rwanda who received a goat from a charity called Heifer International five years ago. It was a life changing event for the family.

Heifer International is an organisation which trains people in better farming practices along with giving them animals and tools to get started. Receiving an animal means the family gets increased food supplies directly through milk or eggs and indirectly through the increased yields of their crops through fertiliser made from dung.

There are other organisation which do this, but the principle that I particularly like about this organisation and their sister organisation Send A Cow, is the "pass it on" principle. The first female offspring of any animal they receive, along with training is passed on to another person, so not only is the first person helped, but they participate in helping another, and the chain continues.

This whole process has dramatic effects on the families receiving gifts. Their health improves through better nutrition. They receive extra income from the abundance of produce. They can afford to send their children to school.

Saturday, 11 April 2015

Pig in a Poke, Mayan Number, Baldwin Effect

1. Pig in a Poke

I'd heard the expression "pig in a poke" before but I didn't know what it meant. Apparently a poke comes from the French word poque (same root as pocket), and means a bag. Don't buy a pig in a poke means don't buy something without looking at it first. A trick in mediaeval times was to put a dog or cat in the bag instead. The trick would be revealed by letting the cat out of the bag.

2. Mayan Numbers

Mayan numbers were constructed using dots (representing 1), dashes (representing 5) and a shell-like symbol which was a placeholder, used like 0 in 103 to indicate that 1 represents 100 rather than 10. It is partially a base 20 system although not quite. For example,

   .
   -       1+5=6 which is multiplied by 18 x 20 x 20

  . .      2 which is multiplied by 18 x 20

   -       5 which is multiplied by 20

  ...      
   _
   _
   _       5+5+5+3=18 (units)

is the number 6x18x20x20 + 2x18x20 + 5x20 + 18 which is 44038.

3. Baldwin Effect

The Baldwin effect is when a learnt behaviour evolves into an inherited instinct through natural selection.

Eggs, AngularJS Scope, Opposable Thumbs

2. Angularjs Scope

In a directive scope:true creates a new scope with prototypical inheritance from the parent scope. When scope: {...} is used, an isolate scope is created which can not read from or write to the parent scope unless specific two-way or one-way bindings are set up.

3. Koalas

Koalas not only have opposable thumbs, but they have two of them on each of their two forefeet.

Tuesday, 7 April 2015

Werewolf, Egg within an Egg, Upside Down Photos

1. Werewolf

When I was looking at the etymology of dummvirate, I saw mention of werewolf. The root of were is also vir, but via the old English, wer meaning man, male person.

2. Egg within an egg

I watched this video of a large egg, which when cracked contained a smaller fully formed egg complete with shell.

I didn't know whether it was a spoof or not, and if not a spoof then how was it formed?

Formation of an Egg

An egg is formed through several stages.

  1. Yolk: The oocyte (yolk) is produced by the ovary, and enters the oviduct.
  2. White: In the first part of the oviduct, the magnum, the yolk is covered with the white (albumen).
  3. Membrane: In the next section of the oviduct, the isthmus, a membrane is deposited over the partially formed egg.
  4. Shell: Next the egg reaches the uterus (shell gland) where a layer of calcium carbonate is deposited around it. This takes between nineteen and twenty-six hours. This forms the shell.
  5. Protective bloom: The last layer, protective bloom, is deposited around the egg. This seals the pores in the shell and keeps the egg fresher for longer.
  6. Finally the egg is laid.

The egg-in-egg phenomenon occurs when a second oocyte is released before the first egg is laid. A contraction occurs, called a counter-peristalsis contraction, which causes the egg to travel backwards through the oviduct, where it joins with the second oocyte to be coated with albumen, membrane and shell again. It ends up as a rather large egg for the poor hen to lay!

3. Upside Down Photos

A friend of mine was having some problems with images on his website. Some of the images displayed upside down and some the right way up. However, when the images were opened in a new tab, they were the right way up. What on earth was going on?

You can take a photo with an iPhone in different orientations. For speed, instead of saving the correctly orientated version of the photo, Apple adds an EXIF tag 'orientation' which tells apps which way up the image should be displayed. Using Jeffrey's Exif Viewer, you can see the details saved along with the image. For example, for an image that was taken with the phone upside down, you get

orientation 180 degree

but for the right way up you instead see

orientation horizontal (normal)

Mystery solved. Now we know what is going on, the next problem is what to do about it. It seems that the solution is to rotate the photos before uploading. There are tools which enable you to do this by rotating based on the orientation. Note that I have not tried and of these tools.