Ficus elastica prefers bright sunlight but not hot temperatures. It has a high tolerance for drought, but prefers humidity and thrives in wet, tropical conditions. Ornamental hybrids (such as Robusta) have been derived from "Ficus elastica" with broader, stiffer and more upright leaves than the wild form. Many such hybrids exist, often with variegated leaves. "Ficus elastica" yields a milky white latex, a chemical compound separate from its sap and carried and stored in different cells. This latex was formerly used to make rubber, but it should not be confused with the Pará rubber tree, the main commercial source of latex for
Fermi liquid theory involve, e.g., a change in the effective mass of particles. The quadratic terms correspond to a sort of "mean-field" interaction between quasiparticles, which is parametrized by so-called Landau Fermi liquid parameters and determines the behaviour of density oscillations (and spin-density oscillations) in the Fermi liquid. Still, these mean-field interactions do not lead to a scattering of quasi-particles with a transfer of particles between different momentum states. The renormalization of the mass of a fluid of interacting fermions can be calculated from first principles using many-body computational techniques. For the two-dimensional homogeneous electron gas, GW calculations and quantum Monte Carlo methods