An electrochemical cell for separating oxygen from the ambient air can be manufactured in a simple manner and inexpensively and both the electrodes and the electrolyte can be manufactured as thin layers. EPMH relates information, analysis, display and control based on the organizing concept of the business components that comprise the CBM map of the enterprise by collecting portfolio information from existing portfolio management tools and generating a portfolio model. A quality score is determined based on the relative occurrence of the one or more keywords within or associated with the harvested content. An attachment structure operably connects the guide tools to the bone screws. When the first current is larger than the second current, the current flowing in the transistor through the mirror circuit is increased to set the transistor to a conducting state, and when the second current is larger than the first current, the current flowing in the transistor through the mirror circuit is increased to set the transistor to a conducting state. The valve may include a groove feature at the location of the openings in the valve shaft which operates to accumulate the flow of hydraulic fluid through the openings and to equalize the pressure exerted by the fluid on the other components of the valve.