function isVerticalSlide( slide ) {

		// Prefer slide argument, otherwise use current slide
		slide = slide ? slide : currentSlide;

		return slide && slide.parentNode && !!slide.parentNode.nodeName.match( /section/i );

	}
Checks if the current or specified slide is vertical
(nested within another slide).

@param {HTMLElement} slide [optional] The slide to check
orientation of