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Algor Mortis
Algor mortis (), the third stage of death, is the change in body temperature post mortem, until the ambient temperature is matched. This is generally a steady decline, although if the ambient temperature is above the body temperature (such as in a hot desert), the change in temperature will be positive, as the (relatively) cooler body equalizes with the warmer environment. External factors can have a significant influence. The term was first used by Bennet Dowler in 1849. The first published measurements of the intervals of temperature after death were done by John Davy in 1839. Applicability A measured rectal temperature can give some indication of the time of death. Although the heat conduction which leads to body cooling follows an exponential decay curve, it can be approximated as a linear process: 2 °C during the first hour and 1 °C per hour until the body nears ambient temperature. The Glaister equation estimates the hours elapsed since death as a linear ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Postmortem Interval Changes (stages Of Death)
An autopsy (also referred to as post-mortem examination, obduction, necropsy, or autopsia cadaverum) is a surgical procedure that consists of a thorough examination of a corpse by dissection to determine the cause, mode, and manner of death; or the exam may be performed to evaluate any disease or injury that may be present for research or educational purposes. The term ''necropsy'' is generally used for non-human animals. Autopsies are usually performed by a specialized medical doctor called a pathologist. Only a small portion of deaths require an autopsy to be performed, under certain circumstances. In most cases, a medical examiner or coroner can determine the cause of death. Purposes of performance Autopsies are performed for either legal or medical purposes. Autopsies can be performed when any of the following information is desired: * Manner of death must be determined ** Determine if death was natural or unnatural ** Injury source and extent on the corpse * Post ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Stage Of Death
The stages of death of a human being have medical, biochemical and legal aspects. The term taphonomy from palaeontology applies to the fate of all kinds of remains of organisms. Forensic taphonomy is concerned with remains of the human body. History The academic study of death is called thanatology, a field pioneered by Élie Metchnikoff in the early 20th century. Thanatology focuses on describing postmortem bodily modifications, as well as perspectives concerning psychosocial, medical, ethical, and spiritual aspects of death. Definition of death Prior to the 1980s, the legal standard defined death as the absence of cardiopulmonary function including the loss of all vital signs. However, as medical technology advanced, there were situations where one might lose brain function and maintain cardiopulmonary function. This led the American Medical Association, the American Bar Association in collaboration with the National Conference of Commissioners on Uniform State Laws to com ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Human Body Temperature
Normal human body temperature (normothermia, euthermia) is the typical temperature range found in humans. The normal human body temperature range is typically stated as . Human body temperature varies. It depends on sex, age, time of day, exertion level, health status (such as illness and menstruation), what part of the body the measurement is taken at, state of consciousness (waking, sleeping, sedated), and emotions. Body temperature is kept in the normal range by a homeostatic function known as thermoregulation, in which adjustment of temperature is triggered by the central nervous system. Methods of measurement Taking a human's temperature is an initial part of a full clinical examination. There are various types of medical thermometers, as well as sites used for measurement, including: * In the rectum (rectal temperature) * In the mouth (oral temperature) * Under the arm (axillary temperature) * In the ear (tympanic temperature) * On the skin of the forehead over the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Desert
A desert is a landscape where little precipitation occurs and, consequently, living conditions create unique biomes and ecosystems. The lack of vegetation exposes the unprotected surface of the ground to denudation. About one-third of the land surface of the Earth is arid or Semi-arid climate, semi-arid. This includes much of the Polar regions of Earth, polar regions, where little precipitation occurs, and which are sometimes called polar deserts or "cold deserts". Deserts can be classified by the amount of precipitation that falls, by the temperature that prevails, by the causes of desertification or by their geographical location. Deserts are formed by weathering processes as large variations in temperature between day and night strain the Rock (geology), rocks, which consequently break in pieces. Although rain seldom occurs in deserts, there are occasional downpours that can result in flash floods. Rain falling on hot rocks can cause them to shatter, and the resulting frag ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Bennet Dowler
Bennet Dowler (1797-1879) was a physician and physiologist of the United States. Biography He was born in Moundsville, Virginia, and received an M.D. from the medical school of the University of Maryland. He settled in Clarksburg, Virginia, where he was postmaster for four years. In 1836, he settled in New Orleans, where he founded the Academy of Sciences, and for some years edited '' The New Orleans Medical and Surgical Journal''. His many experiments upon the condition of the human body immediately after death resulted in valuable discoveries in contractibility, calorification, and capillary circulation. His researches on animal heat, in health, in disease, and after death, which have been published in various medical journals, disclosed the fact that post-mortem calorification after death from fever, cholera, sunstroke, etc., rises in some cases much higher than its antecedent maximum during the progress of the trouble. In 1845 Dowler began a series of experiments in compa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
John Davy (chemist)
John Davy FRS FRSE (24 May 1790 – 24 January 1868) was a Cornish doctor, amateur chemist, brother of the noted chemist Sir Humphry Davy, and cousin of Edmund Davy. During his career, Davy discovered phosgene, silicon tetrafluoride, and concluded that chlorine was an element. Life John Davy was born in Penzance, Cornwall, on 24 May 1790, the son of Robert Davy and his wife, Grace Millet. He assisted his older brother Humphry at the Royal Institution of Great Britain for two years before heading to Edinburgh University, where he earned his degree in medicine in 1814. In 1812, Davy discovered phosgene, a compound he also named. At the same time, he concluded that chlorine was an element. He also discovered silicon tetrafluoride. Upon qualification as a doctor in 1815, Davy joined the British Army Medical Department as an Army Hospital Assistant. From 1816 until 1820 he worked as Staff Surgeon in the General Hospital in Brussels. After being posted to a number of Briti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Glaister Equation
Algor mortis (), the third stage of death, is the change in body temperature post mortem, until the ambient temperature is matched. This is generally a steady decline, although if the ambient temperature is above the body temperature (such as in a hot desert), the change in temperature will be positive, as the (relatively) cooler body equalizes with the warmer environment. External factors can have a significant influence. The term was first used by Bennet Dowler in 1849. The first published measurements of the intervals of temperature after death were done by John Davy in 1839. Applicability A measured rectal temperature can give some indication of the time of death. Although the heat conduction which leads to body cooling follows an exponential decay curve, it can be approximated as a linear process: 2 °C during the first hour and 1 °C per hour until the body nears ambient temperature. The Glaister equation estimates the hours elapsed since death as a linear f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Heat Conduction
Thermal conduction is the diffusion of thermal energy (heat) within one material or between materials in contact. The higher temperature object has molecules with more kinetic energy; collisions between molecules distributes this kinetic energy until an object has the same kinetic energy throughout. Thermal conductivity, frequently represented by , is a property that relates the rate of heat loss per unit area of a material to its rate of change of temperature. Essentially, it is a value that accounts for any property of the material that could change the way it conducts heat. Heat spontaneously flows along a temperature gradient (i.e. from a hotter body to a colder body). For example, heat is conducted from the hotplate of an electric stove to the bottom of a saucepan in contact with it. In the absence of an opposing external driving energy source, within a body or between bodies, temperature differences decay over time, and thermal equilibrium is approached, temperature becomin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Exponential Decay
A quantity is subject to exponential decay if it decreases at a rate proportional to its current value. Symbolically, this process can be expressed by the following differential equation, where is the quantity and (lambda Lambda (; uppercase , lowercase ; , ''lám(b)da'') is the eleventh letter of the Greek alphabet, representing the voiced alveolar lateral approximant . In the system of Greek numerals, lambda has a value of 30. Lambda is derived from the Phoen ...) is a positive rate called the exponential decay constant, disintegration constant, rate constant, or transformation constant: :\frac = -\lambda N(t). The solution to this equation (see #Solution_of_the_differential_equation, derivation below) is: :N(t) = N_0 e^, where is the quantity at time , is the initial quantity, that is, the quantity at time . Measuring rates of decay Mean lifetime If the decaying quantity, ''N''(''t''), is the number of discrete elements in a certain set (mathematics), se ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Linear Function
In mathematics, the term linear function refers to two distinct but related notions: * In calculus and related areas, a linear function is a function whose graph is a straight line, that is, a polynomial function of degree zero or one. For distinguishing such a linear function from the other concept, the term ''affine function'' is often used. * In linear algebra, mathematical analysis, and functional analysis, a linear function is a linear map. As a polynomial function In calculus, analytic geometry and related areas, a linear function is a polynomial of degree one or less, including the zero polynomial (the latter not being considered to have degree zero). When the function is of only one variable, it is of the form :f(x)=ax+b, where and are constants, often real numbers. The graph of such a function of one variable is a nonvertical line. is frequently referred to as the slope of the line, and as the intercept. If ''a > 0'' then the gradient is positive an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Rectal Temperature
The rectum (: rectums or recta) is the final straight portion of the large intestine in humans and some other mammals, and the gut in others. Before expulsion through the anus or cloaca, the rectum stores the feces temporarily. The adult human rectum is about long, and begins at the rectosigmoid junction (the end of the sigmoid colon) at the level of the third sacral vertebra or the sacral promontory depending upon what definition is used. Its diameter is similar to that of the sigmoid colon at its commencement, but it is dilated near its termination, forming the rectal ampulla. It terminates at the level of the anorectal ring (the level of the puborectalis sling) or the dentate line, again depending upon which definition is used. In humans, the rectum is followed by the anal canal, which is about long, before the gastrointestinal tract terminates at the anal verge. The word rectum comes from the Latin '' rēctum intestīnum'', meaning ''straight intestine''. Structure ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Thermal Insulation
Thermal insulation is the reduction of heat transfer (i.e., the transfer of thermal energy between objects of differing temperature) between objects in thermal contact or in range of radiative influence. Thermal insulation can be achieved with specially engineered methods or processes, as well as with suitable object shapes and materials. Heat flow is an inevitable consequence of contact between objects of different temperature. Thermal insulation provides a region of insulation in which thermal conduction is reduced, creating a thermal break or thermal barrier, or thermal radiation is reflected rather than absorbed by the lower-temperature body. The insulating capability of a material is measured as the inverse of thermal conductivity, thermal conductivity (k). Low thermal conductivity is equivalent to high insulating capability (R-value (insulation), resistance value). In thermal engineering, other important properties of insulating materials are product density, density (ρ) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
