$(document).ready
(
  function ()
  {

    var hover = function()
    {
      var trigger = this;
      $(this).addClass('header-active');
      $('.header-logo').each
      (
        function()
        {
          if (this != trigger)
          {
            $(this).animate({opacity: 0.5}, 500);
          }
        }
      );
    }

    $('.header-logo').bind
    (
      'mouseover',
      hover
    );

    var restore = function()
    {
      $('.header-logo').each
      (
        function()
        {
          $(this).animate({opacity: 1}, 100);
          $(this).removeClass('header-active');
        }
      );
    }

    $('.header-logo').bind
    (
      'mouseout',
      restore
    );

  }
);