Human equivalent
Encyclopedia
The term human equivalent is used in a number of different contexts. This term can refer to human equivalents of various comparisons of animate and inanimate things.
s are used to learn more about a disease, its diagnosis
and its treatment
, with animal models predicting human toxicity in up to 71% of cases. The human equivalent dose (HED) or human equivalent concentration (HEC) is the quantity of a chemical that, when administered to humans, produces an effect equal to that produced in test animals by a smaller dose. Calculating the HED is a step in carrying out a clinical trial
of a pharmaceutical drug.
, assuming an average human energy expenditure of 12,500 kJ
per day and a basal metabolic rate
of 80 watt
s. A light bulb running at 100 watts is running at 1.25 human equivalents (100/80), i.e. 1.25 H-e. On the other hand, a human may generate as much as 1,000 watts for a task lasting a few minutes, or even more for a task of a few seconds' duration, while climbing a flight of stairs may represent work at a rate of about 200 watts.
", representing a conversion to human-equivalent years. One formula for cat years is based on a cat reaching maturity in approximately 1 year, which could be seen as 16 in human terms, then adding about 4 years for every year the cat ages. A 5-year-old cat would then be (5 − 1) × 4 + 16 = 32 "cat years" (i.e. human-equivalent years), and a 10-year-old cat (10 − 1) × 4 + 16 = 52 in human terms.
Animal models in chemistry and medicine
Animal modelAnimal model
An animal model is a living, non-human animal used during the research and investigation of human disease, for the purpose of better understanding the disease without the added risk of causing harm to an actual human being during the process...
s are used to learn more about a disease, its diagnosis
Medical diagnosis
Medical diagnosis refers both to the process of attempting to determine or identify a possible disease or disorder , and to the opinion reached by this process...
and its treatment
Therapy
This is a list of types of therapy .* Adventure therapy* Animal-assisted therapy* Aquatic therapy* Aromatherapy* Art and dementia* Art therapy* Authentic Movement* Behavioral therapy* Bibliotherapy* Buteyko Method* Chemotherapy...
, with animal models predicting human toxicity in up to 71% of cases. The human equivalent dose (HED) or human equivalent concentration (HEC) is the quantity of a chemical that, when administered to humans, produces an effect equal to that produced in test animals by a smaller dose. Calculating the HED is a step in carrying out a clinical trial
Clinical trial
Clinical trials are a set of procedures in medical research and drug development that are conducted to allow safety and efficacy data to be collected for health interventions...
of a pharmaceutical drug.
Human energy usage and conversion
The concept of human-equivalent energy (H-e) assists in understanding of energy flows in physical and biological systems by expressing energy units in human terms: it provides a “feel” for the use of a given amount of energy by expressing it in terms of the relative quantity of energy needed for human metabolismMetabolism
Metabolism is the set of chemical reactions that happen in the cells of living organisms to sustain life. These processes allow organisms to grow and reproduce, maintain their structures, and respond to their environments. Metabolism is usually divided into two categories...
, assuming an average human energy expenditure of 12,500 kJ
Joule
The joule ; symbol J) is a derived unit of energy or work in the International System of Units. It is equal to the energy expended in applying a force of one newton through a distance of one metre , or in passing an electric current of one ampere through a resistance of one ohm for one second...
per day and a basal metabolic rate
Basal metabolic rate
Basal Metabolic Rate , and the closely related resting metabolic rate , is the amount of daily energy expended by humans and other animals at rest. Rest is defined as existing in a neutrally temperate environment while in the post-absorptive state...
of 80 watt
Watt
The watt is a derived unit of power in the International System of Units , named after the Scottish engineer James Watt . The unit, defined as one joule per second, measures the rate of energy conversion.-Definition:...
s. A light bulb running at 100 watts is running at 1.25 human equivalents (100/80), i.e. 1.25 H-e. On the other hand, a human may generate as much as 1,000 watts for a task lasting a few minutes, or even more for a task of a few seconds' duration, while climbing a flight of stairs may represent work at a rate of about 200 watts.
Cat and dog years
The ages of domestic cats and dogs are often referred to in terms of "cat years" or "dog yearsAging in dogs
Aging in dogs covers the impact of aging in the domestic dog , common medical and clinical issues arising, and life expectancy.As with humans, advanced years often bring changes in a dog's ability to hear, see and move about easily...
", representing a conversion to human-equivalent years. One formula for cat years is based on a cat reaching maturity in approximately 1 year, which could be seen as 16 in human terms, then adding about 4 years for every year the cat ages. A 5-year-old cat would then be (5 − 1) × 4 + 16 = 32 "cat years" (i.e. human-equivalent years), and a 10-year-old cat (10 − 1) × 4 + 16 = 52 in human terms.
See also
- Animal modelAnimal modelAn animal model is a living, non-human animal used during the research and investigation of human disease, for the purpose of better understanding the disease without the added risk of causing harm to an actual human being during the process...
- BioenergeticsBioenergeticsBioenergetics is the subject of a field of biochemistry that concerns energy flow through living systems. This is an active area of biological research that includes the study of thousands of different cellular processes such as cellular respiration and the many other metabolic processes that can...
- Energy conversionEnergy conversionTransforming energy is when the energy changes into another form.In physics, the term energy describes the capacity to produce changes within a system, without regard to limitations in transformation imposed by entropy...
- Energy qualityEnergy qualityEnergy quality is the contrast between different forms of energy, the different trophic levels in ecological systems and the propensity of energy to convert from one form to another. The concept refers to the empirical experience of the characteristics, or qualia, of different energy forms as they...
- Energy transformation
- MetabolismMetabolismMetabolism is the set of chemical reactions that happen in the cells of living organisms to sustain life. These processes allow organisms to grow and reproduce, maintain their structures, and respond to their environments. Metabolism is usually divided into two categories...