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General Science / How can cell phones affect aircraft "navigational systems"?

« on: 19/09/2007 22:43:18 »

So I was flying home the other day. And as usual - before the flight took off we were asked to turn our cell phones off. Why are we asked to do this? And does it really make a difference to the safety of the flight? The man next to me didn't turn his phone off - he just turned the ringer off. I spent much of the flight trying to decided if I should say something to him. In the end, I did not say anything and we landed safely. But for the future I'd like to know. Thank you.

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Complementary Medicine / Recurrent Cold sores- severe symptoms?

« on: 06/09/2007 21:17:21 »

Most people often cold sores from adults when they are babies.... the virus actually hides in the nerve cell until it's activated - usually by stress and a drop in your body's immune defense. Lots of things can trigger this "re-activation" - bad diet, lack of sleep, too much sun. So wear your sunblock!

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Cells, Microbes & Viruses / Re: Why should the optical density of my bacterial cultures suddenly drop?

« on: 05/09/2007 23:20:33 »

That's pretty hot... but it could be density issues - too many of them killed each other. Or it could be that they used up their growing medium, or they got their own virus (seems unlikely).

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Plant Sciences, Zoology & Evolution / Re: Why do some snakes give birth to live young and other snakes lay eggs?

« on: 05/09/2007 23:15:42 »

Snakes can reproduce in many ways... but all snakes use internal fertilization. As you noted some snakes lay eggs and leave them so they hatch on their own, some retain the eggs within them, and some give birth to live snakes. Those that give birth are really unusual because that kind of reproduction is typically only found in the placental mammals. It's thought that the type of reproduction is based on the environments - so generally eggs outside and live birth occur in cold environments and retention of the eggs inside are found in hotter environments. One snake can reproduce without mating.... check it out here: http://encarta.msn.com/encyclopedia_761578341_3/Snake_(reptile).html.