Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Concept Videos

Pharmacokinetic–Pharmacodynamic Relationship: Intensity of Dose-Effect Relationship01:23

Pharmacokinetic–Pharmacodynamic Relationship: Intensity of Dose-Effect Relationship

86
Pharmacodynamics explores the relationship between drug concentration and its effect. In a quantal response drug, the duration of action better correlates with drug concentration, while for graded effect drugs, the intensity of response is more relevant. This intensity depends on the dose, drug removal rate, and the region of the concentration–response curve.The concentration–response curve can be divided into three regions. Region 3 (80–100% maximum response) demonstrates...
86
Nonlinear Pharmacokinetics: Overview01:19

Nonlinear Pharmacokinetics: Overview

1.3K
Nonlinear or dose-dependent pharmacokinetics is a phenomenon that occurs when the pharmacokinetic parameters of certain drugs deviate from linear pharmacokinetics at higher doses. These drugs do not follow the expected first-order kinetics, where the rate of drug elimination is directly proportional to the drug concentration. Instead, they exhibit a nonlinear relationship, which can be attributed to several factors.
Nonlinearity can arise due to the saturation of plasma protein-binding or...
1.3K
Drug Dependence01:17

Drug Dependence

1.8K
Medications are typically administered to achieve therapeutic effects. Some drugs can modify an individual's mood and perception, frequently resulting in various enjoyable experiences. However, this can result in drug dependency, a condition marked by continuous drug use despite potential negative consequences. Drug dependency primarily falls into two categories: psychological and physical dependence. Psychological dependence occurs when the pleasurable feelings induced by the drug...
1.8K
Pharmacokinetic–Pharmacodynamic Relationship: Dose to Pharmacological Effect01:28

Pharmacokinetic–Pharmacodynamic Relationship: Dose to Pharmacological Effect

68
A drug’s dosage and pharmacokinetic properties determine how quickly it acts, how intense its effects are, and how long it lasts. Higher doses increase drug concentration at receptor sites, producing a hyperbolic curve when pharmacologic response is plotted against drug dose. Converting this scale to a log-linear format results in a sigmoidal curve, better representing dose–response relationships.For drugs following a one-compartment model, the pharmacologic response is directly...
68
Dose Response Curve: Conventional Versus Nonmonotonic01:21

Dose Response Curve: Conventional Versus Nonmonotonic

142
The correlation between a drug's dosage and its impact on a biological system is a cornerstone of pharmacology and toxicology. Conventional dose–response curves, which include graded and quantal relationships, are key to this understanding. Graded dose–response curves depict the spectrum of a biological reaction to different doses within an individual, indicating that as the drug dosage increases, so does the intensity of the response. On the other hand, quantal dose–response...
142
Quantitative Aspects of Drug-Receptor Interaction01:30

Quantitative Aspects of Drug-Receptor Interaction

2.0K
The receptor occupancy theory connects a drug's response to the number of occupied receptors. With higher drug concentrations, more receptors are occupied, leading to increased responses. The formation of drug-receptor complexes involves association and dissociation rates, which reach equilibrium when the forward and backward reactions are equal. The equilibrium association constant (Ka) and its inverse, the equilibrium dissociation constant (Kd), indicate drug affinity. Higher Ka and lower...
2.0K

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by
Same author

Trabecular bone score in people with cystic fibrosis.

Osteoporosis international : a journal established as result of cooperation between the European Foundation for Osteoporosis and the National Osteoporosis Foundation of the USA·2022
Same author

A roadmap for metapopulation research.

Ecology letters·2021
Same author

Comment arising from a paper by Wolda and Dennis: using and interpreting the results of tests for density dependence.

Oecologia·2017
Same author

Avoiding erroneously high levels of detection in combinations of semi-independent tests : An application to testing for density dependence.

Oecologia·2017
Same author

Detection of density dependence from annual censuses of bracken-feeding insects.

Oecologia·2017
Same author

Transcontinental crashes of insect populations?

The American naturalist·2008
Same journal

Unveiling the microhabitat puzzle: how spatial heterogeneity shapes cave invertebrate biodiversity across scales.

Oecologia·2026
Same journal

Soil microbial drought history affects physiological response of select tree species to drought stress.

Oecologia·2026
Same journal

Unveiling the effects of interspecific competition: ecological consequences of competitive release after damming on Salvelinus curilus populations in a three-salmonid species coexistence system.

Oecologia·2026
Same journal

Orchid bee diversity responds positively to forest cover and landscape heterogeneity in the Brazilian Savanna.

Oecologia·2026
Same journal

The impact of native vertebrates on enemy release and plant functional traits during community assembly.

Oecologia·2026
Same journal

Nutrient fluctuations alter effects of litter diversity of invasive species on native communities.

Oecologia·2026
See all related articles

Related Experiment Video

Updated: Mar 6, 2026

Assessment of Dependence in Activities of Daily Living Among Older Patients in an Acute Care Unit
06:52

Assessment of Dependence in Activities of Daily Living Among Older Patients in an Acute Care Unit

Published on: September 30, 2020

10.8K

New insights into testing for density dependence.

M Holyoak1

  • 1Dept. of Biology, Imperial College at Silwood Park, SL5 7PY, Ascot, Berks, UK.

Oecologia
|March 18, 2017
PubMed
Summary
This summary is machine-generated.

This study evaluated time-series tests for density dependence, finding Pollard et al.’s test most reliable. Many common methods actually detect autocorrelation rather than true density dependence, especially with chaotic dynamics.

Keywords:
AttractionAutocorrelationChaosLimitationPower

More Related Videos

Modeling the Size Spectrum for Macroinvertebrates and Fishes in Stream Ecosystems
07:41

Modeling the Size Spectrum for Macroinvertebrates and Fishes in Stream Ecosystems

Published on: July 30, 2019

8.1K
Measurement of Particle Size Distribution in Turbid Solutions by Dynamic Light Scattering Microscopy
09:16

Measurement of Particle Size Distribution in Turbid Solutions by Dynamic Light Scattering Microscopy

Published on: January 9, 2017

14.9K

Related Experiment Videos

Last Updated: Mar 6, 2026

Assessment of Dependence in Activities of Daily Living Among Older Patients in an Acute Care Unit
06:52

Assessment of Dependence in Activities of Daily Living Among Older Patients in an Acute Care Unit

Published on: September 30, 2020

10.8K
Modeling the Size Spectrum for Macroinvertebrates and Fishes in Stream Ecosystems
07:41

Modeling the Size Spectrum for Macroinvertebrates and Fishes in Stream Ecosystems

Published on: July 30, 2019

8.1K
Measurement of Particle Size Distribution in Turbid Solutions by Dynamic Light Scattering Microscopy
09:16

Measurement of Particle Size Distribution in Turbid Solutions by Dynamic Light Scattering Microscopy

Published on: January 9, 2017

14.9K

Area of Science:

  • Ecology
  • Population Dynamics
  • Statistical Ecology

Background:

  • Accurate assessment of density dependence is crucial for understanding population regulation.
  • Existing time-series analysis methods for density dependence yield inconsistent results.
  • The influence of autocorrelation and chaotic dynamics on these tests is poorly understood.

Purpose of the Study:

  • To investigate why time-series tests for density dependence produce variable results.
  • To compare the power and reliability of different statistical tests for density dependence.
  • To determine if these tests primarily detect density dependence or autocorrelation.

Main Methods:

  • Modeled time-series data (20 generations) were generated to simulate various density dependence forms.
  • Evaluated the performance of several established tests: Pollard et al. (1987), Bulmer (1975, two tests), regression of k-value on abundance, and regression of k-value on logarithmic abundance.
  • Assessed test power, susceptibility to data structure, and rates of spurious detection using random-walk models.

Main Results:

  • Pollard et al.’s test demonstrated the highest power and least influence from data form.
  • Bulmer's first test showed moderate power but was more sensitive to data structure.
  • Other methods, including regressions of k-value, exhibited low power and high rates of spurious detection, often indicating autocorrelation instead of density dependence.
  • Crowley's test of attraction showed high power (96-100%) in chaotic dynamics, unlike other tests.

Conclusions:

  • Many commonly used tests for density dependence are unreliable, primarily detecting autocorrelation.
  • Pollard et al.’s test is recommended for its robustness and power in detecting density dependence.
  • Users must be aware of test limitations, especially with low data variation or chaotic dynamics; Crowley's test may be useful for 'attraction'.