Moho
198
especially hydraulic models, in which by some scaling of the governing equations the relevant processes are reproduced on a smaller scale and where
their development is much faster than in reality. An essential problem in
numerical models is the way in which the mathematical model is discretized.
In hydraulic models the scaling requires that the relation between the relevant parameters, as expressed in nondimensional variables, remains the
same (---7similarity theory). Models have to be calibrated by comparison with the
observed past behavior of the prototype. In the calibration certain parameters
governing the behavior of the model can be adapted to obtain an optimal
result. By sensitivity analysis the response of different elements in the model to
external influences is investigated. The reliability of models for prediction is
investigated by validation, that is comparison with a set of independent observations of the prototype. Further development in modelling involves the regular incorporation of information from observations into the model (data
assimilation) in order to improve model predictions.
Moho ---7Mohorovicic discontinuity.
Mohole proposed deep bore hole through the earth's crust to the Mohorovicic discontinuity in order to obtain samples from the underlying mantle.
Mohorovicic discontinuity (abbr. Moho) boundary which separates the earth's crust
and mantle, characterized by an abrupt increase in seismic wave velocity
and an increase in density from approximately 2.9 to 3.2 g cm-3• It is situated 25 to 40 km below continents,S to 10 km below the ocean floor, and 50 to
60 km below mountain ranges. ---7earth's internal structure.
molds filamentous fungi. ---7Fungi.
Mollusca (mollusks) phylum (one of the largest) containing the chitons, snails,
slugs, clams and all other bivalves, squids, octopods and tusk shells. There
are some 75000 living species and 35000 fossil species reaching back as far
as the Cambrium. They occur in all marine habitats, in freshwater, and on land.
The unsegmented, soft-bodied animals are characterized by a muscular foot
(the surface on which they crawl), a calcareous shell secreted by two lobes of
the skin called the mantle, and often by the feeding organ in the mouth called
radula for scraping food. Between the mantle lobes and the body, a space
called mantle cavity hides the "gills" or ctenidia. The Mollusca are divided into
the classes Gastropoda (snails), Monoplacophora, the Polyplacophora (chitons),
Aplacophora, the Bivalvia, Scaphopoda (tooth or tusk shells), and Cephalopoda
(squids, cuttle-fish and octopods).
molting (syn. ecdysis) periodical renewal of the exoskeleton in Arthropoda, which
allows these animals to change their body shape (during juvenile develop-
198
especially hydraulic models, in which by some scaling of the governing equations the relevant processes are reproduced on a smaller scale and where
their development is much faster than in reality. An essential problem in
numerical models is the way in which the mathematical model is discretized.
In hydraulic models the scaling requires that the relation between the relevant parameters, as expressed in nondimensional variables, remains the
same (---7similarity theory). Models have to be calibrated by comparison with the
observed past behavior of the prototype. In the calibration certain parameters
governing the behavior of the model can be adapted to obtain an optimal
result. By sensitivity analysis the response of different elements in the model to
external influences is investigated. The reliability of models for prediction is
investigated by validation, that is comparison with a set of independent observations of the prototype. Further development in modelling involves the regular incorporation of information from observations into the model (data
assimilation) in order to improve model predictions.
Moho ---7Mohorovicic discontinuity.
Mohole proposed deep bore hole through the earth's crust to the Mohorovicic discontinuity in order to obtain samples from the underlying mantle.
Mohorovicic discontinuity (abbr. Moho) boundary which separates the earth's crust
and mantle, characterized by an abrupt increase in seismic wave velocity
and an increase in density from approximately 2.9 to 3.2 g cm-3• It is situated 25 to 40 km below continents,S to 10 km below the ocean floor, and 50 to
60 km below mountain ranges. ---7earth's internal structure.
molds filamentous fungi. ---7Fungi.
Mollusca (mollusks) phylum (one of the largest) containing the chitons, snails,
slugs, clams and all other bivalves, squids, octopods and tusk shells. There
are some 75000 living species and 35000 fossil species reaching back as far
as the Cambrium. They occur in all marine habitats, in freshwater, and on land.
The unsegmented, soft-bodied animals are characterized by a muscular foot
(the surface on which they crawl), a calcareous shell secreted by two lobes of
the skin called the mantle, and often by the feeding organ in the mouth called
radula for scraping food. Between the mantle lobes and the body, a space
called mantle cavity hides the "gills" or ctenidia. The Mollusca are divided into
the classes Gastropoda (snails), Monoplacophora, the Polyplacophora (chitons),
Aplacophora, the Bivalvia, Scaphopoda (tooth or tusk shells), and Cephalopoda
(squids, cuttle-fish and octopods).
molting (syn. ecdysis) periodical renewal of the exoskeleton in Arthropoda, which
allows these animals to change their body shape (during juvenile develop-