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

Signs of Puberty01:27

Signs of Puberty

1.5K
Puberty is a critical phase, typically beginning between the ages of 8 and 13 in girls and 9 and 14 in boys, though timing can vary based on genetics, environmental factors, and overall health. This period is characterized by the development of secondary sexual characteristics and the attainment of reproductive potential. Endocrine changes underpin puberty, with hormonal surges of Luteinizing Hormone (LH) and Follicle-Stimulating Hormone (FSH) instigated by Gonadotropin-Releasing Hormone (GnRH)...
1.5K
Introduction to the Sign Test01:10

Introduction to the Sign Test

1.3K
The sign test is an important tool in nonparametric statistics, offering a straightforward yet effective method for analyzing matched pairs, nominal data, or hypotheses concerning the median of a population. It transforms data points into positive or negative signs, avoiding the need for assumptions about data distribution and instead focusing on the direction of change. It is particularly valuable when data does not conform to the normal distribution requirements of many parametric tests. For...
1.3K
Sign Convention01:30

Sign Convention

3.4K
When analyzing a beam subjected to various loads, it is crucial to understand the internal forces and moments generated within the structure. These internal forces can be broadly classified into normal forces, shear forces, and bending moments. To determine these forces and moments, we use the method of sections and apply a specific sign convention based on their direction and the side of the section being analyzed.
The normal force acts perpendicular to the beam's cross-section and can...
3.4K
Sign Test for Nominal Data01:12

Sign Test for Nominal Data

384
The sign test is a nonparametric method used to evaluate hypotheses about the median of a single sample or to compare the medians of two related samples. The sign test is particularly useful when dealing with nominal data, which includes distinct categories without an inherent order, such as names, labels, and preferences. Nominal data restricts statistical analysis to evaluating population proportions rather than mean or median values that require continuous data.
For example, consider a...
384
Introduction to Vital Signs01:25

Introduction to Vital Signs

7.6K
Vital signs are physiological measurements that help key into the status of the body's essential functions. These include body temperature, pulse rate, respiratory rate, and blood pressure, commonly abbreviated as T, P, R, and BP. Some healthcare settings also consider oxygen saturation (SpO2) and, in specific contexts, pain and level of consciousness as additional vital signs.
Vital signs help healthcare professionals assess an individual's well-being and detect any functional changes...
7.6K
Sign Test for Matched Pairs01:17

Sign Test for Matched Pairs

386
The sign test for matched pairs offers a robust method for comparing two paired samples, often for the effects of an intervention in one of them. This method is very useful in situations where the underlying distribution of the data is unknown. The test compares two related samples—often pre- and post-treatment measurements on the same subjects—to determine if there are significant differences in their median values.
To conduct the sign test, we first calculate the differences in...
386

You might also read

Related Articles

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

Sort by
Same author

Regulation of Transpiration and Whole-Tree Crown Conductance in Tropical Forests.

Plant, cell & environment·2026
Same author

Soil fertility controls on tropical forest productivity and mortality: synthesis and roadmap.

The New phytologist·2026
Same author

Tropical forest carbon sequestration accelerated by nitrogen.

Nature communications·2026
Same author

Drought Response Is Not a Species Trait: Tropical Tree Drought Sensitivity Is Shaped by Drought Characteristics, Species Adaptations and Individual Microenvironments.

Ecology letters·2025
Same author

Drying suppresses fine root production to 1 m depths and alters root traits in four distinct tropical forests.

The New phytologist·2025
Same author

Memories of Trees Past: Coexistence Implications of Legacy Conspecific Density Dependence.

Ecology letters·2025

Related Experiment Video

Updated: Jan 21, 2026

A System to Create Stable Nanoparticle Aerosols from Nanopowders
12:59

A System to Create Stable Nanoparticle Aerosols from Nanopowders

Published on: July 26, 2016

9.9K

Signs of stabilisation and stable coexistence.

Maarten J E Broekman1, Helene C Muller-Landau2, Marco D Visser3

  • 1Department of Plant Ecology and Physiology, Institute for Water and Wetland Research, Radboud University, Nijmegen, The Netherlands.

Ecology Letters
|July 23, 2019
PubMed
Summary

Empirical evidence for negative density, frequency, and plant-soil feedback aids ecological stabilization but doesn't guarantee stable coexistence. Stronger tests for coexistence require invasibility experiments or model parameterization.

Keywords:
CoexistenceLotka-Volterracompetitionconspecific effectsdensity-dependencefitness differencesfrequency-dependenceheterospecific effectsniche differencesplantsoil feedbackstabilisation

More Related Videos

Generation of Stable Transgenic C. elegans Using Microinjection
12:09

Generation of Stable Transgenic C. elegans Using Microinjection

Published on: August 15, 2008

54.2K
Author Spotlight: A Stable Phantom Material for Optical and Acoustic Imaging
04:54

Author Spotlight: A Stable Phantom Material for Optical and Acoustic Imaging

Published on: June 16, 2023

3.7K

Related Experiment Videos

Last Updated: Jan 21, 2026

A System to Create Stable Nanoparticle Aerosols from Nanopowders
12:59

A System to Create Stable Nanoparticle Aerosols from Nanopowders

Published on: July 26, 2016

9.9K
Generation of Stable Transgenic C. elegans Using Microinjection
12:09

Generation of Stable Transgenic C. elegans Using Microinjection

Published on: August 15, 2008

54.2K
Author Spotlight: A Stable Phantom Material for Optical and Acoustic Imaging
04:54

Author Spotlight: A Stable Phantom Material for Optical and Acoustic Imaging

Published on: June 16, 2023

3.7K

Area of Science:

  • Ecology
  • Population Biology
  • Theoretical Ecology

Background:

  • Empirical studies often quantify negative density dependence, negative frequency dependence, or negative plant-soil feedback.
  • The direct links between these empirical findings and ecological theory for stable coexistence are often unclear.

Purpose of the Study:

  • To connect empirical measures of density dependence, frequency dependence, and plant-soil feedback to theoretical conditions for stabilization and stable coexistence.
  • To evaluate the sufficiency of common empirical tests for predicting stable coexistence in ecological communities.

Main Methods:

  • Relating empirical results to classical competition models and theoretical conditions for stabilization.
  • Analyzing whether common empirical tests provide necessary or sufficient conditions for stable coexistence in two- and multi-species systems.
  • Discussing invasibility experiments and model parameterization as approaches for stronger coexistence tests.

Main Results:

  • Most tests for negative density dependence, negative frequency dependence, and negative plant-soil feedback are sufficient for ecological stabilization in two-species interactions.
  • These empirical tests are neither necessary nor sufficient for stable coexistence of two species.
  • Inferences are more limited for multi-species communities and single-life-stage/vital rate measurements.

Conclusions:

  • While empirical measures indicate stabilization, they do not reliably predict stable coexistence.
  • Model parameterization offers a robust approach to link empirical data with coexistence mechanisms.
  • Invasibility experiments and model parameterization provide stronger frameworks for testing stable coexistence.