Related Concept Videos

Types of Selection01:46

Types of Selection

Natural selection influences the frequencies of particular alleles and phenotypes within populations in several different ways. Primarily, natural selection can be directional, stabilizing, or disruptive. Directional selection favors one extreme trait and shifts the population towards that phenotype while selecting against individuals displaying alternate traits. Stabilizing selection favors an intermediate trait with a narrow range of variation. Deviation from the optimal phenotype towards an...
Methods of Sterilization I: Physical Methods01:29

Methods of Sterilization I: Physical Methods

As used in a healthcare facility, sterilization destroys all microorganisms through physical or chemical methods. The physical method includes steam, dry heat, boiling water, and radiation.
Steam sterilization uses non-toxic, low-cost moist heat in the form of saturated steam under pressure, which is fast, microbicidal, and sporicidal, and quickly warms and penetrates fabrics. Autoclaves, or steam sterilizers, expose each item to direct steam contact for a predetermined time at the necessary...
Methods of Sterilization II: Chemical Methods01:30

Methods of Sterilization II: Chemical Methods

In healthcare, the chemical method of sterilization uses chemical sterilants to treat surgical instruments and medical supplies to help prevent the transmission of infectious pathogens to patients. Due to heat sensitivity, most medical supplies and equipment should not be exposed to high temperatures. These parts include rubber, plastic, glass, and other similar elements.
Using chemical sterilization rather than heat to clean out equipment is recommended. It eradicates and removes all bacteria,...
Birth Control Methods01:22

Birth Control Methods

Vasectomy is a surgical form of male sterilization that involves severing and sealing the vasa deferentia, preventing sperm from mixing with semen during ejaculation. Because a vasectomy does not impact the testes' ability to produce testosterone, hormone levels, libido, and sexual function generally remain unchanged. While vasectomy is highly effective in preventing pregnancy, with a success rate near 99.85%, rare cases of recanalization (spontaneous reconnection) can occur. Although vasectomy...
The Bell Curve01:21

The Bell Curve

The normal probability distribution, often depicted as a symmetrical, bell-shaped curve, is fundamental in statistics and the study of natural phenomena. This pattern, famously described by mathematician Carl Friedrich Gauss, shows how data points are distributed around a central mean, with most values near the average and fewer observations occurring as they deviate further from it.
This pattern applies to many human characteristics beyond intelligence, such as height. For example, if you...
Psychosurgery01:30

Psychosurgery

Psychosurgery, the surgical alteration or permanent removal of brain tissue to alleviate severe psychological conditions, stands as one of the most radical and controversial treatments in the history of mental health care. Its development and application have evolved significantly, marked by dramatic shifts in scientific understanding and ethical perspectives.
Historical Development of Psychosurgery
In the 1930s, Portuguese neurologist Antonio Egas Moniz introduced a surgical procedure designed...