There are latitudinal gradients in species diversity. Deep ocean currents are driven by density and temperature gradients. It exists only in an atmosphere with horizontal temperature gradients. This can be alleviated by regularization, such as penalization of states with large spatial gradients. Some refer to the buffy coat when separating cells by Ficoll density gradients. Peaks and troughs usually connected by smooth gradients are called clines. These different water masses affect gradients and mixing of nutrients and dissolved gasses. This term may include factors such as composition, compositional gradients, stresses, and magnetic fields. In 1973, Dreyfus used backpropagation to adapt parameters of controllers in proportion to error gradients. In particular, the maintenance of precise osmotic gradients of electrolytes is important. In 1973 Dreyfus adapts parameters of controllers in proportion to error gradients. A new promising means is looking for quasi-particle refraction in systems with strong magnetic gradients. Arbuscular mycorrhizal fungi vary across many environmental gradients. Field homogeneity is measured by examining an FID signal in the absence of field gradients. Regulation is achieved via protein concentration gradients, called morphogenic fields.