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[A] [B] [C] [D] [E] [F] [G] [H] [I] [J] [K] [L] [M] [N] [O] [P] [Q] [R] [S] [T] [U] [V] [W] [X] [Y] [Z]

Q
Quest constant. The area of discovery when parasite density is 1.

Q10
A relationship for the effect of temperature on a process such that the process rate increases by the same multiple for every 10°C rise in temperature.

Qualitative variables
Variables concerning qualitative or attribute data. The data are not necessarily representable in numerical form.

Quality assurance
Those procedures and controls designed to monitor the conduct of toxicological studies in order to assure the quality of the data and the integrity of the study.

Quantal effect
An effect that either happens or does not happen, e.g. death.

Quantal response
An all-or-none response of the individuals composing a population; e.g. the act of germination is a quantal response because, after some time, a spore is either germinated or not.

Quantile-quantile plot
A method to compare a sample distribution with a theoretical distribution by plotting the quantiles of the theoretical distribution against the sample quantiles.

Quantitative variables
Variables concerning quantitative or measurement data. The data can be represented on a numerical scale.

Quarantine
All operations associated with prevention of importation of unwanted organisms into a territory or that exportation from it e.g. the holding of imported material in isolation for a period to ensure freedom from diseases and pests. (1) A legal action in which there is a control on the import and export of plants to prevent spread of pathogens and pests; (2) Holding of imported plants in isolation for a period to ensure their freedom from diseases and plants. Control of import and export of plants to prevent spread of diseases and pests.

Quartan malaria
Malaria with fevers recurring every 72 hours. Caused by Plasmodium malariae.

Quartiles
Three values that divide the total frequency of a set of data into four equal parts. The central value is called the median and the other two are called the upper and lower quartiles, respectively.

Queuing theory
The study of the formation of lines or queues when the arrivals occur at random intervals.

Quick-breaking emulsion
An emulsion in which the components separate rapidly.

Quiescence
That period of the preparation stage during which a pathogen may be inactive because environmental conditions are unfavourable for its growth.

Quiescent
Not growing.

Quota sampling
The selection of a predetermined number of elements from different sectors of the population.

Quotidian malaria
Malaria with fevers recurring every 24 hours. Found in cases of overlapping infections.