Reduction in leaf surface may be related to the necessity of reducing water loss through the process of transpiration, a requirement for existence in a desert environment.
A fundamental requirement for existence in strongly acidic environments is generation of a large pH gradient (delta pH) to maintain the cytoplasmic pH near neutrality and safeguard the acid-labile cell constituents.
As a point of entry to the idea that there could be notions of dependence not easily analysable in terms of the modal-existential account, consider the fact that not all forms of dependence seem to involve a requirement for existence at all.
Tissue homeostasis is one of the central requirements for the existence of multicellular organisms, and is maintained by complex feedback regulatory processes.
An existing empirical relation between this packing density and the aspect ratio of the rods, in conjunction with micro-rheological requirements for the existence of such rods, results in an equation describing the critical volume fraction of the minor phase for complete co-continuity as a function of the matrix viscosity, interfacial tension, shear rate and phase dimensions.
There are two main requirements for the existence of these bursting oscillations [22 24, 32].
One of the most basic requirements for the existence of life around a star is the ability of that star to produce a terrestrial planet of sufficient mass to sustain it.
While ice-free ground suitable for nesting is a key requirement for the existence of Adélie penguin colonies, the species also requires accessible marine foraging grounds and sufficiently abundant prey to survive.
It is assumed that the system is unknown-input functional detectable, which is the least requirement for the existence of a stable UIFO.
The main limitation of our approach is the requirement for the existence of a sufficient number of high resolution structures of complexes comprised by functionally similar proteins.
(43 - 47 43 - 4750) and all linear w.r.t. the state variables that constitute state L E, so the requirement for the existence of at least 6 (n m) linear relations is satisfied, which enables back-translation in step three of the method.
