2014/07/016e4_exercise_51lxsdSEDcL._SL160_

Window of opportunity against HIV comes from ‘fitness bottleneck’

New research on HIV transmission shows that viral fitness is an important basis of a “genetic bottleneck” imposed every time a new person is infected. The findings define a window of opportunity for drugs or vaccines to prevent or limit infection.

HIV represents evolution on overdrive. Every infected individual contains a swarm of viruses that exhibit variability in their RNA sequence, and new mutations are constantly appearing. Yet nearly every time someone new is infected, this diverse population of viruses gets squeezed down to just one individual.

The genetic bottleneck effect was known, but now the selection for viral fitness driving it is becoming clear. Researchers have found that viral protein sequences matching a consensus sequence, which is hypothesized to be most fit, are more likely to be transmitted than those that deviate from the consensus.

The results are scheduled for publication this week in Science.

“The best explanation for what we are seeing is that frequently, after exposure to HIV, a few cells in the genital tract are infected, without establishment of a systemic infection,” says senior investigator Eric Hunter, PhD, professor of pathology and laboratory medicine at Emory University School of Medicine, Emory Vaccine Center, and Yerkes National Primate Research Center. Hunter is a Georgia Research Alliance Eminent Scholar.

“We now have evidence that the game isn’t lost as soon as the first target cell is infected. It suggests that any approach that makes it more difficult for the virus to replicate in a cell, or that targets infected cells for killing before they can release new viruses, will reduce the probability of systemic infection.”

Scientists led by Hunter at Emory Vaccine Center/Center for AIDS Research teamed up with lead author Jonathan Carlson, PhD, and colleagues at Microsoft Research. The team collaborated with Susan Allen at Emory, and her HIV prevention programs in Zambia that enroll heterosexual couples with one HIV-positive partner. These programs provide counseling and condoms, but HIV transmission still occurs despite a two-thirds reduction in the infection rate.

Regular blood tests and close monitoring allowed the researchers to compare the virus that gets transmitted to the viruses in the chronically infected partner, for 137 transmission events over 10 years. Further monitoring in the first two years of infection permitted the team to track the effects of viral mutations.

“We hypothesized that individual mutations in viral genes could be expected to have a range of effects on the virus’s ability to replicate, to infect new cells and escape the immune system,” Carlson says. “What we found was that even minor changes away from the consensus HIV-1 sequence had a measurable effect on the likelihood of transmission.”

This selection bias was reduced in couples where there was a higher risk of transmission. In particular, the fitness bottleneck was less severe in male-to-female transmission than in female-to-male. It was also less severe in

… Continue reading here.
Fitness News — Sciencedaily
— Courtesy “Science News Daily” (ScienceNewsDaily.com) <p>

This is perhaps the most important exercise to learn and practice for guitar and an excellent warm up for guitarists of any level. If you find my videos usef…
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Comments

    • Pa Khat Nu
    • July 14, 2014
    Reply

    Great.. I Love Guitor..
    But I don’t know how to play …
    I want to become Guitor player in my future…

    View Comment
    • Shona Kearney
    • July 14, 2014
    Reply

    I always figured I’d have to break every bone in my hand to be able to play
    the guitar. This is a great exercise – it’s kind of like gaining the muscle
    memory to release the clutch learning how to drive standard. Great video –
    kudos!

    View Comment
    • Baltazar Madrigal Tapia
    • July 14, 2014
    Reply

    How did you learn to play a guitar

    View Comment
    • Cebu Rizalista
    • July 14, 2014
    Reply

    hey guys, i want your help. i just bought an acoustic guitar and started
    doing the things in this video. however, i have these really small hands
    and a tiny pinky. could this hinder my playing? i am asian, filipino to be
    exact. 

    View Comment
    • xPanicFiex
    • July 14, 2014
    Reply

    I was number 1,000,000 ! xD

    View Comment
    • dwheel39
    • July 14, 2014
    Reply

    thanks for the tip!

    View Comment
    • Guitar101Ramstein
    • July 14, 2014
    Reply

    Thanks, the exercise works good for any level of playing, I use it all the
    time as a warm up before playing.

    View Comment
    • Guitar101Ramstein
    • July 14, 2014
    Reply

    Chromatic scale is 12 notes.

    View Comment
    • cynquan
    • July 14, 2014
    Reply

    bull shit

    View Comment
    • GamesSpartan
    • July 14, 2014
    Reply

    I wish I found this video 5 years ago….

    View Comment
    • HypnoticPropaganda
    • July 14, 2014
    Reply

    Excellent! You have a nice voice too… 🙂

    View Comment
    • Joachim Dias
    • July 14, 2014
    Reply

    Hi, I have a few questions. 1. When you play the standard exercise, do you
    have to make sure your fingers only touch the string you are playing or
    does it not matter if they touch the string below? (as you are only playing
    on 1 string at a time 2. How does the vertical position of the thumb along
    the neck changes as you go from 6th to 1st string? 3. How do you remove
    your fingers from the fret to make a nice sound with pull off in strings
    2-6? Thanks a lot!

    View Comment
    • abby detering
    • July 14, 2014
    Reply

    This is so I’m not going to be able to play guitar ever!

    View Comment
    • Francisco Domalewski
    • July 14, 2014
    Reply

    Wow. This is the most helpful video on guitar that I have ever watched. My
    finger dexterity has gotten so much better thanks to this video. Thank you

    View Comment
    • Linds
    • July 14, 2014
    Reply

    Thanks for the exorcise! I’m finding it really hard to stretch my fingers
    out on the top strings without lifting the unused fingers. I can get the
    bottom few just fine though. I have really small hands. Any tips?

    View Comment
    • Elena Starr
    • July 14, 2014
    Reply
    • mishmash2373
    • July 14, 2014
    Reply

    this is really great stuff, very informative and helpful!! THANKYOU!

    View Comment
    • TheWhoDatWhoady
    • July 14, 2014
    Reply

    Do you recommend alternate strumming with the right hand while doing this
    drill, or not really?

    View Comment
    • Daniel F
    • July 14, 2014
    Reply

    nice guitar, chief…is that an ibanez or a yamaha?

    View Comment
    • JERRYR708
    • July 14, 2014
    Reply

    Added to my favorites.

    View Comment
    • computerman789
    • July 14, 2014
    Reply

    I will be an expert at fingering in both ways, this way and you know…

    View Comment
    • Sai2ify
    • July 14, 2014
    Reply

    My fingers are sooo stiff!they kind of hurt when I try moving them up and
    down!!ghrrrr

    View Comment
    • ChabotDustin
    • July 14, 2014
    Reply

    Awesome! Thank you I’m just starting and this will help my fingers! Keep
    posting

    View Comment
    • Crush Steado
    • July 14, 2014
    Reply

    FINGERING!!!!! hahaha lol like if u get

    View Comment

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