populations

Examples of populations in the following topics:

• The Vocabulary Epidemiology

  • Epidemiology is the study of the patterns, causes, and effects of health and disease conditions in set populations.
  • However, the term is widely used in studies of zoological populations (veterinary epidemiology) and of plant populations (botanical or plant disease epidemiology).
  • The distinction between "epidemic" and "endemic" was first drawn by Hippocrates, to distinguish between diseases that are "visited upon" a population (epidemic) from those that "reside within" a population (endemic).
  • A pandemic is an epidemic of infectious disease that has spread through human populations across a large region; for instance multiple continents, or even worldwide.
  • Prevalence is the proportion of the total number of cases to the total population and is more a measure of the burden of the disease on society.

• Growth Rate and Temperature

  • Hence, local doubling of the bacterial population occurs.
  • However, if the number surviving exceeds unity on average, the bacterial population undergoes exponential growth .
  • Bacterial growth in batch culture can be modeled with four different phases: (A) the lag phase, when the population stays roughly the same; (B) the exponential, or log, phase, when the population grows at an increasing rate; (C) the stationary phase, when population growth stagnates; and (D) the death phase, when bacteria begin to die off and the population decreases in size.

• Analytical Epidemiology

  • Epidemiology draws statistical inferences, mostly about causes of disease in populations based on available samples of it.
  • Epidemiology is the study (or the science of the study) of the patterns, causes, and effects of health and disease conditions in defined populations.
  • Where descriptive epidemiology describes occurrence of disease (or of its determinants) within a population, the analytical epidemiology aims to gain knowledge on the quality and the amount of influence that determinants have on the occurrence of disease.

• Quorum Sensing

  • Quorum sensing is a system of stimulus and response correlated to population density.
  • Quorum sensing is a system of stimulus and response correlated to population density.
  • Many species of bacteria use quorum sensing to coordinate gene expression according to the density of their local population.
  • Bacteria use quorum sensing to coordinate certain behaviors based on the local density of the bacterial population .
  • However, as the population grows, the concentration of the inducer passes a threshold, causing more inducer to be synthesized.

• Current Epidemics

  • An epidemic occurs when new cases of a disease, in a given human population, and during a given period, substantially exceed expectations.
  • In epidemiology, an epidemic occurs when new cases of a certain disease, in a given human population, and during a given period, substantially exceed what is expected based on recent experience.
  • Epidemics of infectious disease are generally caused by a change in the ecology of the host population (e.g. increased stress or increase in the density of a vector species), a genetic change in the parasite population or the introduction of a new parasite to a host population (by movement of parasites or hosts).
  • Generally, an epidemic occurs when host immunity to a parasite population is suddenly reduced below that found in the endemic equilibrium and the transmission threshold is exceeded.

• Pure Culture

  • A pure culture is a population of cells or multicellular organisms growing in the absence of other species or types.
  • A pure (or axenic) culture is a population of cells or multicellular organisms growing in the absence of other species or types.

• Descriptive Epidemiology

  • The goal of epidemiology is to establish causal factors for health issues in order to improve the health and safety of entire populations.
  • A population can refer to a town, country, age group, or race.
  • For epidemiologists, data on who is most likely to be injured in car crashes can be just as valuable as a topic of inquiry as data on what part of the population is most at risk for developing complications from the flu.

• Oligotrophs

  • Oligotrophs are characterized by slow growth, low rates of metabolism, and generally low population density.
  • Oligotrophs are characterized by slow growth, low rates of metabolism, and generally low population density.

• Generation Time

  • Therefore, "local doubling" of the bacterial population occurs.
  • If the number surviving exceeds unity on average, the bacterial population undergoes exponential growth.
  • The number of new bacteria appearing per unit time is proportional to the present population.
  • If growth is not limited, doubling will continue at a constant rate so both the number of cells and the rate of population increase doubles with each consecutive time period.

• History of Epidemiology

  • Epidemiology is the study of the patterns, causes, and effects of health and disease conditions in defined populations.
  • Epidemiology is the study of the patterns, causes, and effects of health and disease conditions in defined populations.
  • The distinction between "epidemic" and "endemic" was first drawn by Hippocrates, to distinguish between diseases that are "visited upon" a population (epidemic) from those that "reside within" a population (endemic).
  • Epidemiologists also study the interaction of diseases in a population, a condition known as a syndemic.