dispersal


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dis·per·sion

(dis-pĕr'zhŭn),
1. The act of dispersing or of being dispersed. Synonym(s): dispersal
2. Incorporation of the particles of one substance into the mass of another, including solutions, suspensions, and colloidal dispersions (solutions).
3. Specifically, what is usually called a colloidal solution.
4. The extent or degree in which values of a statistical frequency distribution are scattered about a mean or median value.
[L. dispersio]

dispersal

the act of disseminating or scattering the seeds of plants, or the larvae of animals (particularly important in sessile animals), or any movement of adults. Animal larvae may be mobile, but the dispersal of spores, seeds and fruits is brought about by wind, water and animals, and in some plants explosive mechanisms are present.

Many mechanisms exist to aid dispersal: some fruits, e.g. teasel, burdock, are hooked, becoming attached to the bodies of animals; some parasites use vectors (e.g. a mosquito in the case of the malarial parasite), to carry parasitic organisms between hosts; and some larvae of marine animals move to different layers of water where current direction may be different from the level at which the adults live. Dispersal techniques include EMIGRATION, IMMIGRATION and MIGRATION.

References in periodicals archive ?
Aerial Dispersal of Pollen and Spores covers dozens of topics within the study of pollen and spore dispersal, such as the physical properties, forces, and processes affecting pollen and spores--in motion and at rest; pollen and spore survival; infection and fertilization efficiency; wind and wind transport models; cross fertilization; pollen mediated gene flow; precision agriculture practices applied to aerially dispersed pathogens; infectious periods and opportunity for disease spread; aerial sampling, and more.
The mericarps of Salvia are small but larger than dust seeds or spores, so they are small enough to be transported by wind but unlikely to achieve long-distance dispersal except by extreme winds.
Larval dispersal has not been well studied in relation to abalone species.
Sumalbag was the jeepney driver who was mercilessly brutalized by policemen just as he was fleeing the violent dispersal. For obvious reasons, he felt threatened and harassed and is now in fear for his life and safety after such visit.
He explained: "This dispersal zone has been set up despite the best efforts to combat anti-social behaviour.
"The dispersal order for Caerphilly town centre complements our Town Safe initiative, which aims to reduce drunken behaviour and related anti-social behaviour and violence linked to the night-time economy."
Biogeographic patterns and dispersal pathways were analyzed using PAE, a quantitative biogeographic method used for reconstructing hierarchical area relationships in the absence of phylogenetic information (Rosen & Smith 1988).
The hypothesis that we examined was that passive dispersal by balsam woolly adelgid can be explained using readily available wind data.
In the dispersal type--the umbilical vessels undergo successive division with gradually diminishing caliber towards periphery, while in magistral type the umbilical vessels is characterized by the arteries that traverse to the edge of placenta without appreciable decrease in diameter of vessels.
Dispersal of asylum seekers tears the woman away not only from her social network but from midwives with whom she needs to build a trusting and compassionate relationship...
Several studies on dispersal of this species have been conducted (11-21), indicating high variability in the range of 20 m (12) to 1 [km.sup.6].