In the present study, REE-bearing mineral(s) suspended in the groundwater cannot be directly observed by SEM observation because of the very low concentration of colloids in groundwater.
This change is initially concentrated in the central regions of the star where it cannot be directly observed, but it alters some observable properties of the star, such as brightness and surface temperature, and these alterations are taken as evidence of what is going on in the interior.
These parameters and characterize the relations between hidden and observed variables that cannot be directly observed during training and are usually not uniquely identifiable.
Cronbach and Meehl (1955) [ 28] define a construct as a concept for which there is not a single observable referent, which cannot be directly observed, and for which there exist multiple referents, but none all-inclusive.
Rather, learning is a mental process that cannot be directly observed.
Interview a scientist about how one goes about coming up with a theory about a phenomenon that cannot be directly observed.
As with most geologic processes that cannot be directly observed, a certain amount of uncertainty exists about how cumulates form.
Since the total energy radiated by a star cannot be directly observed (except in the case of the Sun), the effective temperature is a derived quantity rather than an observed one.
Whereas sedimentary rocks are produced by processes operating mainly at the Earth's surface by the disintegration of mostly older igneous rocks, igneous and metamorphic rocks are formed by internal processes that cannot be directly observed and that necessitate the use of physical-chemical arguments to deduce their origins.
Instrumental measurements provided additional information about trunk and root injuries, which cannot be directly observed.
At the regional or global scale, carbon fluxes (i.e. NPP) cannot be directly observed [2].
