Basic question about: <<- and method start with dot.

Dear list,

When I read some source code, I find lot of place used  symbol <<- , e.g.

lastTime <<- newTime;

What is the meaning here?

Also, I find some method with the name start with dot, e.g.

.RowStandardizeCentered = function(x) {
	div = sqrt( rowSums(x^2) );
	div[ div == 0 ] = 1;
	return( x/div );
}

What is the special meaning for the method name start with a dot?