Through the 2008 Summer Games, the U.S. has never won a medal in handball, table tennis, rhythmic gymnastics, and badminton. According to the olympic website, the US has 3 events it has never won a medal in----I know one of them is Handball, but do not know the other two. Through the 2006 Winter Games, the U.S. has never won a medal in biathlon and nordic combined.
The circle with the arrow means male, and the circle with the plus sign means female. the circle with a plus-sign is used as the zodiacal symbol for the planet Venus. It is the female and male sign. the one in your question with the top pointing up is male, and the one with the cross pointing down, is female.
However, it's been common practice for Christianity to adopt ancient pagan symbols and rituals into its own belief system, making it a very good possibility that the original knotwork symbols were, indeed, Celtic to begin with. The Circle. Sometimes, the traditional triquetra symbol is accompanied by a circle. The circle, in many belief systems, is a symbol of eternity. Whether it is the eternity of God's love or the eternal circle of life itself, the circle adds even more weight to the significance of the triquetra.