Universal Encyclopedia of Knowledge

Explore and learn something new!

  • All
  • Acoustics
  • Algebra
  • Anatomy
  • Anthropology
  • Archeology
  • Architecture
  • Arts
  • Astronomers
  • Astronomy
  • Astrophysics
  • Biology
  • Botany
  • Chemistry
  • Cosmology
  • Economics
  • Electromagnetism
  • Electronics
  • Electrotechnics
  • Engineering
  • Engineers
  • Fluid Mechanics
  • Geography
  • Geology
  • Geometry
  • History
  • Informatics
  • Insects
  • Jurisprudence
  • Linguistics
  • Literature
  • Materials Science
  • Mathematicians
  • Mathematics
  • Mechanics
  • Medicine
  • Metrology
  • Minerals
  • Music
  • Nanotechnology
  • Optics
  • Pathology
  • Pedagogy
  • Philosophers
  • Philosophy
  • Physicists
  • Physics
  • Physiologists
  • Physiology
  • Politics
  • Psychiatry
  • Psychologists
  • Psychology
  • Religion
  • Sociologists
  • Sociology
  • Statistics
  • Theologians
  • Thermodynamics
  • Writers
  • Zoology


An etiopathogenesis is defined as the analysis of the causes and development of a disease or abnormal condition. The term derives from the union of “etiology” and “pathogenesis”, which in the medical field indicate, respectively, the causal factors (etiology) and the mechanism of onset, and subsequent development, of a disease process (pathogenesis). The etiopathogenesis may be certain […]

Etiopathogenesis Keep reading »


Rotation is defined as rigid movement having as fixed points a point called center (in two dimensions) or a straight line called axis (in three dimensions) of rotation. This movement shifts all points around the center, or axis, by a fixed angle. In other words a rotation is the movement of a body following a circular

Rotation Keep reading »

Mass number

An element’s mass number (A) is the sum of the number of protons and the number of neutrons. The small contribution of mass from electrons is disregarded in calculating the mass number. This approximation of mass can be used to easily calculate how many neutrons an element has by simply subtracting the number of protons from the

Mass number Keep reading »


Pathogenesis investigates the development of a disease and the chain of events associated with it, which step by step determine morphofunctional changes in cells and tissues belonging to the affected organs. These alterations can be caused by chemical, physical, or biological agents (viruses, bacteria, etc.). We could therefore define pathogenesis as the mechanism by which an

Pathogenesis Keep reading »

Roto-translation (rigid transformation)

The rigid transformation (or roto-translation motion) is the composition between reflection, translation, and rotation, and therefore it is an isometry, that is, a geometric transformation that leaves the distances unchanged. In other words, we can think of roto-translation as a rigid movement in which a geometric figure first rotates and then translates. The rototranslation motion of a rigid body

Roto-translation (rigid transformation) Keep reading »

Environmental economics

Environmental economics is a branch of political economy concerned with environmental issues. The birth of the discipline is conventionally set between the 1950s and 1960s, although some basic concepts had been developed earlier. The importance of the discipline has grown during the 21st century because of increasing environmental concerns. Some key issues are the costs

Environmental economics Keep reading »

Electromagnetic interaction

The electromagnetic interaction is responsible for the chemical properties of atoms and the structure of molecules. The electric charge determines the intensity and the direction of the interaction between charged bodies, bodies with equal electric charges repel each other, while bodies with opposite electric charges attract each other. The electromagnetic force is the result of local interaction

Electromagnetic interaction Keep reading »


Infrasound sometimes referred to as low-frequency sound, lower in frequency than 20 Hz or cycles per second of the “normal“ limit of human hearing (20 kHz). Infrasound is characterized by an ability to get around obstacles with little dissipation. The study of such sound waves is sometimes referred to as infrasonics, covering sounds beneath 20 Hz down

Infrasound Keep reading »

Criminal anthropology

Criminal anthropology is the branch of criminology that studies criminals on the basis of their behavior, their somatic indices, the various morphological abnormalities, integrating them with the data of psychopathology and sociology. Founder of this science is commonly considered Cesare Lombroso, followed by G. Marro, E. Ferri, R. Garofalo, A. Gemelli, N. Pende, B. di

Criminal anthropology Keep reading »

Fowl cholera

Fowl cholera (also called avian cholera, avian pasteurellosis, avian hemorrhagic septicemia) an infectious disease affecting almost all birds, sustained by Pasteurella multocida, a gram-negative, immobile, asporiginal, facultative anaerobic bacterium. Affected birds are most often chickens, ducks, turkeys, geese, guinea fowl, rarely pigeons and pheasants. Healthy carriers are very important in the spread of the disease; in fact, in the

Fowl cholera Keep reading »


Thermodispersion is the term used to indicate the set of processes by which the release of heat from the body surface is realized. Thermodispersion together with thermogenesis (heat production) contributes to keeping the body temperature constant (thermoregulation). Thermodispersion is particularly important in case of increased body temperature (fever), which requires an extra supply of fluids; it

Thermodispersion Keep reading »

Stable nuclide

Stable nuclides are nuclides that are not radioactive and so (unlike radionuclides) do not spontaneously undergo radioactive decay. When such nuclides are referred to in relation to specific elements, they are usually termed stable isotopes. Only 90 nuclides of the first 40 elements are energetically stable for any type of decay except, in theory, proton

Stable nuclide Keep reading »


Consciousness describes our awareness of internal and external stimuli. Awareness of internal stimuli includes feeling pain, hunger, thirst, sleepiness, and being aware of our thoughts and emotions. Awareness of external stimuli includes seeing the light from the sun, feeling the warmth of a room, and hearing the voice of a friend. States of consciousness vary over the

Consciousness Keep reading »

Distribution (economics)

In economics the term distribution generally refers to activities of transferring goods from production sources to final consumption. It involves goods-producing enterprises, true commercial enterprises (wholesale and retail), and auxiliary transportation, warehousing, and advertising enterprises, which together constitute the distribution apparatus. In this postwar period, distribution techniques and the distribution system underwent radical changes to

Distribution (economics) Keep reading »

Modern physics

Modern physics is defined as the set of theoretical and experimental scientific developments since the twentieth century, have marked a conceptual leap from classical physics, developed since the seventeenth century, to explain phenomena that were not describable with a “classical” approach (quantum mechanics, theory of relativity). It is not possible to indicate with precision a

Modern physics Keep reading »


Antiferromagnetism is a characteristic property of some materials such as manganese, chromium, hematite, oxides MnO2, FeO, CoO, etc. (called antiferromagnetic materials); in these materials, contrary to what happens for ferromagnetic materials (in which the configuration of minimum energy occurs for parallel spins), the interaction between the atoms is such as to create a configuration of minimum energy when

Antiferromagnetism Keep reading »


A hydrophone (Ancient Greek: ὕδωρ + φωνή, lit. ’water + sound’) is a microphone designed to be used underwater for recording or listening to underwater sound. Most hydrophones consist of a piezoelectric transducer that translates mechanical energy resulting from a change in pressure into electrical energy. Some piezoelectric materials, or transducers, can convert a sound into an electrical

Hydrophone Keep reading »


The myelencephalon contains the medulla oblongata or bulb and is the caudocranial continuation of the spinal cord. It is the lower part of the brain stem. It protrudes, in its lower part, for a short distance outside the foramen magnum of the occipital bone. Externally it shows an anterior, two lateral and one posterior face. On the

Myelencephalon Keep reading »


An airlock, air-lock or air lock, is a compartment with doors which can be sealed against pressure which permits the passage of people and objects between environments of differing pressure or atmospheric composition while minimizing the change of pressure in the adjoining spaces and mixing of environments. Airlocks find application in many fields, especially in:

Airlock Keep reading »

Permanent tissue

Permanent tissues may be defined as a group of living or dead cells formed by meristematic tissue and have lost their ability to divide and have permanently placed at fixed positions in the plant body. Meristematic tissues that take up a specific role lose the ability to divide. This process of taking up a permanent shape,

Permanent tissue Keep reading »

Monetary economics

Monetary economics is the branch of political economy that studies the determinants of money supply and demand and their consequences on the real economy. The need to regulate exchanges without resorting to barter, in complex economic systems, has led mankind to adopt as a medium of exchange in commercial activities an instrument that is easy

Monetary economics Keep reading »

Demagnetization [degaussing]

The demagnetization is the process by which the magnetic charge is eliminated from an object, both of a ferrous metal nature and of another nature. Degaussing is the process of decreasing or eliminating a remnant magnetic field. It is named after the gauss, a unit of magnetism, which in turn was named after Carl Friedrich Gauss. Due to magnetic hysteresis, it is generally not

Demagnetization [degaussing] Keep reading »

Scroll to Top