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

Nondisjunction01:21

Nondisjunction

Nondisjunction is the failure of homologous chromosomes or sister chromatids to separate correctly and move to the opposite poles of the cells. This produces daughter cells with abnormal chromosome numbers.  Nondisjunction is common during anaphase I or anaphase II of meiosis.  Mutations in synaptonemal complex proteins that attach homologous chromosomes increase the chances of nondisjunction in anaphase I of meiosis I. In contrast, mutations in topoisomerases and condensins that hold sister...
Nondisjunction01:29

Nondisjunction

During meiosis, chromosomes occasionally separate improperly. This occurs due to failure of homologous chromosome separation during meiosis I or failed sister chromatid separation during meiosis II. In some species, notably plants, nondisjunction can result in an organism with an entire additional set of chromosomes, which is called polyploidy. In humans, nondisjunction can occur during male or female gametogenesis and the resulting gametes possess one too many or one too few chromosomes.
Population Growth00:57

Population Growth

Population size is dynamic, increasing with birth rates and immigration, and decreasing with death rates and emigration. In ideal conditions with unlimited resources, populations can increase exponentially, which plots as a J-shaped growth rate curve of population size against time. This type of curve is characteristic of newly-introduced invasive species, or populations that have suffered catastrophic declines and are rebounding.
The Ratio of X Chromosome to Autosomes02:45

The Ratio of X Chromosome to Autosomes

In most organisms, sex is determined by the ratio of X and Y chromosomes. However, in some organisms, such as Drosophila and C.elegans, sex is determined by the ratio of the number of X chromosomes to the number of sets of autosomes. The Y chromosome in Drosophila is active but does not determine sex. It contains genes responsible for the production of sperms in adult flies.  
Normal male Drosophila has a ratio of one X chromosome to two sets of autosomes. In contrast, normal female Drosophila...
Infertility in Males01:23

Infertility in Males

Male infertility affects millions of couples worldwide, arising from various factors that impact different stages of the reproductive process. An endocrine imbalance resulting from conditions like hypogonadism, Klinefelter syndrome, or pituitary disorders can disrupt hormone levels and reduce sperm production. Testicular defects, such as tumors, cryptorchidism, atrophic testes, abnormal sperm morphology, and low sperm count or motility, may arise due to genetic factors, structural...
Testing a Claim about Population Proportion01:24

Testing a Claim about Population Proportion

A complete procedure for testing a claim about a population proportion is provided here.
There are two methods of testing a claim about a population proportion: (1) Using the sample proportion from the data where a binomial distribution is approximated to the normal distribution and (2) Using the binomial probabilities calculated from the data.
The first method uses normal distribution as an approximation to the binomial distribution. The requirements are as follows: sample size is large...

You might also read

Related Articles

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

Sort by
Same author

Late third trimester diagnosis of congenital giant hemangioma complicated by the Kasabach-Merritt phenomen: a case report and literature review.

The journal of maternal-fetal & neonatal medicine : the official journal of the European Association of Perinatal Medicine, the Federation of Asia and Oceania Perinatal Societies, the International Society of Perinatal Obstetricians·2023
Same author

Author Correction: Enteric α-synuclein impairs intestinal epithelial barrier through caspase-1-inflammasome signaling in Parkinson's disease before brain pathology.

NPJ Parkinson's disease·2023
Same author

Homogenization modelling of antibiotic diffusion and adsorption in viral liquid crystals.

Royal Society open science·2023
Same author

Localized waves in elastic plates with perturbed honeycomb arrays of constraints.

Philosophical transactions. Series A, Mathematical, physical, and engineering sciences·2022
Same author

Subgingival periodontal pathogens in Down syndrome children without periodontal breakdown. A case-control study on deciduous teeth.

European journal of paediatric dentistry·2022
Same author

Enteric α-synuclein impairs intestinal epithelial barrier through caspase-1-inflammasome signaling in Parkinson's disease before brain pathology.

NPJ Parkinson's disease·2022
Same journal

Solvent Extraction of Metals in the Circular Economy: Enhancing Resource Efficiency and Sustainability.

TheScientificWorldJournal·2026
Same journal

Agronomic Performance and Nutritive Value Evaluation of Desho Grass Varieties Under Supplementary Irrigation in Western Oromia, Ethiopia.

TheScientificWorldJournal·2026
Same journal

Physicians' and Hospital Administrators' Perspectives of Diagnosis-Related Groups (DRGs) in High-Income Countries: A Systematic Review.

TheScientificWorldJournal·2026
Same journal

The Eco-Friendly Preparation of Se, Zn, and Ag MONPs and Their Current Medical Applications and Drug Delivery for AD Diseases.

TheScientificWorldJournal·2026
Same journal

Fear of COVID-19: A Comparative Study Among University Students in Peru.

TheScientificWorldJournal·2026
Same journal

Opportunities and Challenges of Integrating Ethiopian Traditional Medicine System Into Modern Medicine: A Narrative Review.

TheScientificWorldJournal·2026
See all related articles

Related Experiment Video

Updated: May 20, 2026

Scanning Skeletal Remains for Bone Mineral Density in Forensic Contexts
07:56

Scanning Skeletal Remains for Bone Mineral Density in Forensic Contexts

Published on: January 29, 2018

A decrease in sex ratio at birth nine months after the earthquake in L'Aquila.

A D'Alfonso1, F Patacchiola, I Colagrande

  • 1Department of Gynecology and Obstetrics, San Salvatore Hospital, L'Aquila, Italy.

Thescientificworldjournal
|July 5, 2012
PubMed
Summary
This summary is machine-generated.

The L'Aquila earthquake significantly reduced the secondary sex ratio (SSR) in the months following the event. This study highlights the impact of major stress events on the sex ratio at birth.

More Related Videos

Basic Methods for the Study of Reproductive Ecology of Fish in Aquaria
07:25

Basic Methods for the Study of Reproductive Ecology of Fish in Aquaria

Published on: July 20, 2017

A Noninvasive Method For In situ Determination of Mating Success in Female American Lobsters (Homarus americanus)
10:18

A Noninvasive Method For In situ Determination of Mating Success in Female American Lobsters (Homarus americanus)

Published on: February 7, 2014

Related Experiment Videos

Last Updated: May 20, 2026

Scanning Skeletal Remains for Bone Mineral Density in Forensic Contexts
07:56

Scanning Skeletal Remains for Bone Mineral Density in Forensic Contexts

Published on: January 29, 2018

Basic Methods for the Study of Reproductive Ecology of Fish in Aquaria
07:25

Basic Methods for the Study of Reproductive Ecology of Fish in Aquaria

Published on: July 20, 2017

A Noninvasive Method For In situ Determination of Mating Success in Female American Lobsters (Homarus americanus)
10:18

A Noninvasive Method For In situ Determination of Mating Success in Female American Lobsters (Homarus americanus)

Published on: February 7, 2014

Area of Science:

  • Reproductive biology
  • Environmental health

Background:

  • The secondary sex ratio (SSR) is influenced by various factors, including stress.
  • Stress appears to disproportionately affect male births.

Purpose of the Study:

  • To assess the impact of the L'Aquila earthquake on the SSR.
  • To investigate potential links between natural disasters and reproductive outcomes.

Main Methods:

  • Comparative analysis of SSR data from January-June 2010 versus January-June 2008.
  • Statistical analysis using chi-square and Fisher's exact tests.

Main Results:

  • A notable decrease in SSR was observed nine months post-earthquake (Jan 2010 vs. Jan 2008: 0.62 vs. 0.96).
  • Overall SSR declined in early 2010 compared to early 2008 (0.82 vs. 1.11).
  • A statistically significant increase in SSR was found within 2010 (first 3 months vs. second 3 months: 0.82 vs. 1.27).

Conclusions:

  • The L'Aquila earthquake was associated with a significant reduction in the secondary sex ratio.
  • Major environmental stressors may influence the sex ratio at birth, potentially affecting male fetal development.