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Erin Nash

Declining Male Fertility Linked To Water Pollution - 1 views

www.sciencedaily.com/...090118200636.htm

science fertility sci_i research

shared by Erin Nash on 25 May 11 - Cached
  • Some of these are contained in medicines, including cancer treatments, pharmaceutical treatments, and pesticides used in agriculture. The research suggests that when they get into the water system, these chemicals may play a pivotal role in causing feminising effects in male fish
    • Erin Nash
      Erin Nash on 25 May 11
       
      Do these chemicals just cause these problems in vertebrates, like fish? Would it be possible to obtain chemicals like this, and test them on an invertebrate species?
  • Found in some industrial chemicals and the contraceptive pill,
    • Erin Nash
      Erin Nash on 25 May 11
       
      Birth control pills could cause this? How would that actually work? How could a birth control pill cause a male to change gender? What levels of the hormone are required to cause this gender change?
Marcy Withrow

Hens Eject Sperm from Unwelcome Suitors | Female Control & Battle of Sexes | Chicken Se... - 0 views

www.livescience.com/5828-chickens-eject-sperm.html

shared by Marcy Withrow on 31 Aug 11 - No Cached
    • Marcy Withrow
      Marcy Withrow on 31 Aug 11
       
      I think I learned this in DC Biology that hens can do that. which is crazy!!
    • Erin Nash
      Erin Nash on 31 Aug 11
       
      Yes - we watched a video about this with ducks!
  • A new study has shown that, during an average ejection, a hen jettisons 80 percent of the sperm a rooster deposits in her reproductive tract. This has a huge impact on the competition among males fighting to father her future chicks, according to study researcher Tommaso Pizzari, an evolutionary biologist and university lecturer at Oxford University in the United Kingdom.  
    • Marcy Withrow
      Marcy Withrow on 31 Aug 11
       
      This means that only the best of the best hens have chicks! That stinks for the loser hens..
    • Erin Nash
      Erin Nash on 31 Aug 11
       
      The best of the roosters will have chicks - that's natural selection in action!
  • ...10 more annotations...
  • Hens, however, often don't have a choice in mates. They prefer males at the top of the pecking order, but other roosters with lower status will force the hens — about half their size — to mate.
    • Marcy Withrow
      Marcy Withrow on 31 Aug 11
       
      So, they know what they want. but, sometimes they get taken advantage of, because roosters are bigger than them. But, then they can reject their sperm and choose what's best for the offspring.
  • Scientists already knew that hens could eject sperm, but in the recent study, they set out to find evidence that hens were actively using this technique to control fertilization.
    • Marcy Withrow
      Marcy Withrow on 31 Aug 11
       
      They already knew this, but now they are seeing if the hen actually controls the fertilization. that's nuts!
  • They then videotaped any sperm ejection that followed the mating and collected the results. To determine how this compared with the total sperm the roosters had deposited, the researchers captured all of their semen during another set of controlled mating attempts.
    • Marcy Withrow
      Marcy Withrow on 31 Aug 11
       
      this is how they tested it. I wonder how you would videotape sperm exactly.
    • Erin Nash
      Erin Nash on 31 Aug 11
       
      Ha! I wonder that as well!
  • When mating with a series of roosters, hens ejected more semen from the later mates. Since lower-status roosters don't get the first shot at the hens, for this reason alone, their sperm are more likely to be ejected, Pizzari explained.
    • Marcy Withrow
      Marcy Withrow on 31 Aug 11
       
      It's like they know which ones are lower status and have timed it perfectly to get rid of their sperm.
    • Erin Nash
      Erin Nash on 31 Aug 11
       
      They would know because of size, behavior, etc.
  • n addition, lower status roosters were more likely to ejaculate more semen in one shot, and the team found that hens were more likely to eject larger ejaculations.
    • Marcy Withrow
      Marcy Withrow on 31 Aug 11
       
      I wonder why they ejaculate so much? Do they not get enough action??
    • Erin Nash
      Erin Nash on 31 Aug 11
       
      Ha! Maybe they're trying to make up for their low status, in some odd way?
Jessica Ball

Pesticide exposure may contribute to ADHD, study finds - 2 views

www.sciencedaily.com/...100517132846.htm

shared by Jessica Ball on 25 Aug 11 - Cached
    • Erin Nash
      Erin Nash on 25 Aug 11
       
      This is a potentially interesting idea - especially in a farming region. Would you find a higher rate of ADHD cases in an area where pesticide use was more prevalent? 
  • "Previous studies have shown that exposure to some organophosphate compounds cause hyperactivity and cognitive deficits in animals,"
    • Erin Nash
      Erin Nash on 25 Aug 11
       
      This is super interesting, but I wouldn't be sure about how to go about testing it. Having ADHD is a "private" medical condition - so would you have to ask for volunteers? If you do, they aren't chosen at random. Also, how do you test urine for those compounds? Could this study be recreated with mice?
  • ...1 more annotation...
    • Jessica Ball
      Jessica Ball on 29 Aug 11
       
      It seems like a pretty far stretch to think that pesticides contribute to ADHD. In my opinion, it is more genetic or a result of the environment (stress, tension, etc.), not chemicals floating around.
    • Erin Nash
      Erin Nash on 29 Aug 11
       
      Oh - no - it is entirely possible. Chemicals in the environment can have incredibly nasty side effects - and pesticides aren't just floating around - they are often on your fruits and vegetables. Scientists think birth control is causing male fish to develop eggs in their testes - trace amounts in the water from wastewater treatment plants. This actually is quite possible!!
    • Erin Nash
      Erin Nash on 29 Aug 11
       
      Oh - and have you ever smelled the "smell" when you cross the river on 229? I can smelll the chemicals (fertilizers/pesticides) from the industries downtown - as far north as the avenue near Lafayette. You have chemical traces in your hair...etc :)
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