Aerifying larger lawns requires a power-driven core aerator or aerifier, which can be rented at lawn and garden supply centers. The working parts of these machines are spoon-shaped tines or hollow tubes. As the tubes are driven into the lawn, cores of soil are removed from the ground and strewn across the lawn.
Nutrients with the Highest Energy Density. Fat provides more calories than any other nutrient. The macronutrients -- fat, protein and carbohydrates -- are high in energy density, which means that they have 4 or more calories per gram. The other essential nutrients -- water, vitamins and minerals -- have no calories, so they provide no energy.
1 A new study analyzed levels of 17 nutrients in food considered to be important to lower your risk of heart disease and cancer in order to determine the top powerhouse fruits and vegetables.  Topping the list in terms of nutrient density are watercress, Chinese cabbage, chard, beet greens, and spinach.