Le site de vulgarisation scientifique de l’Université de Liège. ULg, Université de Liège

Glossary

Vous trouverez dans ce glossaire les définitions de termes présents dans les différents articles, classés de manière alphabétique.

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
I
IBSA

The IBSA dialogue forum (India, Brazil and South Africa) has been organizing high-level annual summits since 2003 between presidents and heads of government in the objective of strengthening South-South cooperation in many sectors. It acts with multilateral organizations to favor commercial interests and permanent compliance with the United Nations Security Council in these three countries.

Ice line

The ice line of a star marks the boundary beyond which an entire series of volatile substances condense in the form of ice. The ice line of the sun is at 5 astronomical units from its surface, that is, between the asteroid belt and the orbit of Jupiter.

ICOMOS

The International Council on Monuments and Sites, ICOMOS, is a worldwide association of professionals who are concerned with the conservation and protection of monuments, groups of historic buildings and cultural heritage sites. It was created in 1965 in Warsaw and Cracow, Poland. The Venice Charter was adopted by the Second International Congress of Architects and Technicians of Historic Monuments in 1964; the Venice Charter is the founding text of that organization, and remains its primary statement of principle.

ICOMOS is a non-governmental international organization whose principal activity is the promotion of the theory, method and technique of conservation, protection and affirmation of the worth and value of monuments and historic sites.

ICOMOS is also mentioned in the World Heritage Convention of UNESCO as the consultative agency for the implementation of the Convention, and it acts as a scientific advisor for the Committee on World Heritage regarding the inclusion of monuments and cultural sites on the World Heritage List. ICOMOS has observer status in regard to the Council of Europe.

icterus

Icterus is a yellow discoloration of the skin, commonly known as jaundice.
Icterus occurs if the liver is suffering from an acute disease, such as hepatitis, but it can also be the sign of hepatic decompensation, when the liver damaged by cirrhosis can no longer process bilirubin (resulting from a degradation of the red blood cells). When this bilirubin can no longer be evacuated through the bile to the digestive system, it accumulates in the blood. The skin and the whites of the eyes become yellow while the stools turn pale ("clay" coloured). Icterus may be accompanied by severe itching, due to the accumulation of bile salts under the skin.

ideology

According to Le Robert dictionary, it refers to a collection of organised concepts allowing a society to define its nature, the way it functions and the objectives it pursues. While in terms of the ternary system (a way of thinking elaborated in the 10th century by scholars) the word is incontestably applicable, its use in terms of Franco-Italia could be problematical. Despite the multitude of vague reflections tossed about by the “court authors”, the concepts gathered here all tend towards a single goal: to define a French Italy and Frenchified Italians.  Since the various ways of achieving this contribute to the elaboration of this way of thinking, the use of the term “ideology” is altogether relevant here.

IgE

Category of antibody that is particularly involved in allergic processes.

Imaginary

An individual and collective capacity to create an ensemble of values, standards and truths which construct our vision of politics and history, which directs our behaviour, and which above all manages to achieve autonomy, in other words to present itself as something given from the outside, as if it preceded us, independently of our own creating activities.

Immunodeficient

An immune system is immunodeficient when its response to infections and tumours is reduced.

Immunogen

Capacity of an antigen to induce an immune response, and make the body produce antibodies.

Immunogenicity

The aptitude of an antigen to stimulate an immune response.

Immunoglobulin

Large group of membrane or soluble glycoproteins involved in cell recognition, binding and adhesion. Among other things, this family contains antigen binding molecules such as antibodies. These molecules play a crucial role in the interactions between the cells involved in the immune system.

Immunohistochemistry

Laboratory technique based on antibody-antigene recognition whereby specific molecules present near/in a cell can be visualized.

Immunosuppressor

Substance that inhibits or prevents the activity of the immune system.

immunotherapy

Therapeutic strategy which aims to improve the functioning of an organism’s defense or immune system.

Impressionism

A school of painting privileging, in its choice of subjects, light, the outdoors and the panoply of fugitive impressions which have their source in objects which are necessarily in motion. Within it, influenced from 1874 by the innovative work of a Manet (1832-1883), these artists – amongst whom we can identify Frédéric Bazille (1841-1870), Paul Cézanne (1839-1906), Auguste Renoir (1841-1919) and above all Claude Monet (1840-1926) – were opposed to realism and were sensitive to everything which touched on the transitive, even the evanescent. But the term is also applied to the manner in which musicians who, like Claude Debussy (1862-1918), have contributed to revolutionising our auditory perception, particularly through the fluidity of the sounds and sequences of their compositions. Characteristics which are discovered, mutatis mutandis, in a number of symbolist authors drawn to the depiction of the delicacy of sentiments and feelings.

In silico

In opposition to the terms _in vivo_ and _in vitro_, in silico signifies research on living organisms carried out numerically, with the aid of computer tools, such as mathematical models, for example.

In utero

From the Latin for ‘in the uterus’; phenomena which occur in the uterus and which can effect the embryo or foetus.

In vitro

From the Latin for ‘in the glass’; qualifies the phenomena which take place outside of a living organism or in cells.

In vivo

From the Latin for ‘within a living being’; qualifies exams or research practiced on living organisms.

Inborn immunity

The immunity we have available at birth, to be distinguished from acquired immunity.

incrustation

In video, incrustation consists of electronically separating part of an image, creating a ‘hole’ and enabling the inlaying of another image in its place.

Inflammation

a collection of events appearing at an irritation point following the invasion of a pathogenic agent. The inflammation is manifested by four main signs: redness, warmth, swelling and pain.

inflorescence

Various groups of flowers.

inflorescence meristem

The meristem which initiates floral meristems, but which remains itself undifferentiated so it can produce a group of flowers or 'inflorescence'.

Infrared

Electromagnetic radiation (or “light”) that is propagated in wavelengths that are invisible to the naked eye, ranging from 0.7 to 100 micrometers. Infrared radiation is associated with heat, because many objects emit infrared radiation spontaneously at room temperature. Infrared light is used in many technologies. -night-vision equipment (warmer objects show up as brighter) ; -infrared thermography that allows one to measure temperatures at a distance ; -missile guidance systems (infrared detectors guide missiles toward a source of heat, for example the jet engine of a targeted aircraft) ; -communication over short distances from a computer to its peripheral devices.

Infrared spectrometry

An analysis technique based on the absorption of infrared radiation by a sample whose properties and composition one wants to study. The analysis is carried out by scanning wave lengths and obtaining an infrared spectrum which presents the absorption bands.

inhibitor

A compound whose function is to slow or stop a chemical process.

Innate immune system

a component of the immune system corresponding to non-specific defence mechanisms such as physical barriers (skin, eyelashes, mucous membranes, etc.), polynuclear neutrophils, phagocytic cells, the complement system, etc.

Composé organique ">

Compound that contains neither carbon nor hydrogen (water, sulphate, ammonia, etc.), as opposed to organic compounds.

inorganic pigments

These pigments come from mineral resources. In particular, they contain metals such as iron or cadmium. Inorganic pigments are most often opaque and matt.

Inquisition

A special ecclesiastical tribunal created by the papacy to fight against heresy through means of a special procedure, the inquisition (inquisitio). Instituted in 1199 by Pope Innocent III to get the better of the Catharist movement in south-west France, the Inquisition was primarily active from the 13th to the 16th centuries in Christian Europe (apart from England). The inquisitional process (interrogation, torture, punishments, ranging from flagellation to the stake) was initially confided to the Dominican order and was particularly used in the 16th century against Muslims and Jews.

Insulin

A hormone secreted by the pancreas, whose deficiency brings about diabetes. Insulin allows the levels of glucose in the blood to be reduced.

Integrins

A family of cellular receptors which bind to extracellular matrix molecules and play a very important role in the migration, differentiation and survival of the cell.

Intellectual Property Law

Law that gathers the rules related to intellectual creations and to distinctive signs. It covers artistic, literary and industrial property.

interactome

Refers to all interactions between macromolecules (DNA, RNA, proteins) within a cell.

Interferometry

In astrophysics interferometry consists of observing a target simultaneously with several telescopes and subsequently combining the light beams received by each telescope by superposing them at a common focus. This ploy thereby produces an angular resolution similar to that of a giant telescope whose diameter would be equal to the separation between the individual telescopes.

interferon

Interferons are proteins produced by our immune system in response to certain attacks, for instance, by viruses. They stimulate immunity through various complementary routes. They also participate in the rejection of cancerous cells.
It is currently possible to produce human interferons for pharmaceutical use, which are used as antiviral and anticancer drugs, and in the treatment of multiple sclerosis.  
In the case of hepatitis C, α interferon is coupled with polyethylene glycol to increase its duration of action. This “pegylated interferon”, combined with ribavirin, gives very good results. 
Unfortunately, interferons cause rather unpleasant side effects, such as pronounced flu-like symptoms (fever, fatigue, mylagia).

intergrowth texture

In a particle of rock, the intergrowth texture illustrates the way the crystals of the different minerals that make up the rock are interwoven.

Interleukin

Regulatory molecules produced when the body is subjected to microbial attack. Thus, for example, interleukin-1 acts on the neurons of the hypothalamus which thus make the body temperature rise beyond 37°C. For its part IL-6 causes an acute reaction and can play an anti-inflammatory role.

International Atomic Energy Agency (IAEA)

The principal world authority concerning scientific and technological co-operation in the field of the peaceful use of nuclear energy. The IAEA has also been given responsibility for an important mission to avoid the proliferation of nuclear weapons. The Agency currently brings together 153 Member States. Its headquarters is in Vienna. It was founded by the United Nations, in 1957, as a response to the ‘Atoms for peace’ speech made by the United States President, Dwight Eisenhower, who suggested the creation of an international body responsible for promoting and monitoring the civil and peaceful use of nuclear energy. As an offshoot of the United Nations (UN), one of its major objectives is to assure the safety of populations and states in fighting against any illicit attempt to use nuclear fission for military purposes. To guarantee and verify the peaceful use of nuclear energy, the IAEA is responsible for inspecting nuclear activities and installations throughout the world. It verifies that the Non Nuclear Weapons States (NNWS) which have signed the Treaty on the Non-Proliferation of Nuclear Weapons (NPT) respect their commitments in order to avoid the peaceful use of nuclear technology being diverted to military ends.

To succeed in this mission it encourages non signatory states to join the NPT and conclude safeguard agreements. After the discovery of a certain number of clandestine programmes, a strengthening of the controls was defined in an Additional Protocol to the NPT. If the IAEA can demonstrate that a State has not respected its obligations, it refers it to the UN’s Security Council, which decides what consequences should follow.

In recent years, activity in this domain has been marked by the difficult relationships Western nations and the IAEA has had with Iran, suspected of wishing to equip itself with an atomic weapon in order to ‘safeguard’ its territory (render it beyond attack) against the potential threats from within its geopolitical environment, and notably from Israel, a country equipped with a nuclear arsenal. To date no formal proof has nevertheless been produced that Iran is developing a nuclear weapon.

Moreover the IAEA and its Director General, Mohamed ElBaradei, jointly received the Nobel Peace Prize, on December 1, 2005, for ‘their efforts in preventing prevent nuclear energy being used for military ends.’

International atomic time (TAI)

Time scale founded on the frequency of radiation emitted by caesium-133 atoms. A second is  precisely defined as being the duration of 9192631770 periods of the radiation corresponding to the transition between the hyperfine levels F=3 and F=4 of the fundamental state of the caesium-133 atom.

International Criminal Court

The International Criminal Court (ICC) is the first permanent international criminal court created by treaty to contribute to ending impunity for the most serious crimes which affect the international community, such as crimes of genocide, crimes against humanity and war crimes. It is governed by its founding treaty, the Rome Statute, signed by 124 countries. It sits in The Hague (Netherlands). 

The ICC is an independent international organisation which does not belong to the system of the United Nations. It is used as a last resort. It does not intervene when a case is already being investigated or prosecuted in a national legal system unless these cases are not conducted in good faith, for example, if they have been used to shield an individual from criminal responsibility.

International Unit

In pharmacology, is the unit of measurement of a substance, based on the biological activity measured (or its effect). The abbreviation IU is widely used in medicine packaging.

Interneurons

Type of neurons characterized by the shortness of their dendritic and axonal projections.

Intron

Part of the gene which, in eukaryotic organisms, is eliminated during the formation of messenger RNA (i.e. which encode proteins) from pre-messenger RNA. The sequences thus formed are called "intrusive sequences".

Introns

The genes are made up by a suite of alternate exons and introns. The intron is a fraction of DNA present in a gene, intercalated between the exons, which is lacking information related to the synthesis of a protein and whose role is still poorly understood.

Intrusive thoughts

Unwanted thoughts of different kinds (anxiety, self doubt, etc.) which perturbs the ongoing cognitive functioning.

IOM

Institute of Medicine, this has since become the National Academy of Medicine. An American organ which brings together scientific experts from committees in order to determine independent recommendations and opinions.

Ion

An electrically charged atom or molecule.

ionosphere

The ionosphere is the Earth’s upper atmosphere, which extends approximately from an altitude of 85 km to 800 km. Its name refers to its state of electrical conductivity which is characterised by a partial ionisation of the gasses. The ionosphere can be subdivided into three layers (D, E, F) according to the concentration in ions.

IPCC

The Intergovernmental Panel on Climate Change was set up in 1988, at the request of the G7, the club made up of the world’s seven richest countries (the United States, Japan, Germany, France, Great Britain, Canada and Italy), under the auspices of the United Nations, by the World Meteorological Organisation (WMO) and the United Nations Environment Programme (UNEP). It is presided over by the Indian engineer and economist Rajendra Pachauri, a Honoris Causa Doctor at the University of Liège, who was re-elected in 2008 for another mandate of six years at the head of the organization.

IRA

Irish Republican Army. This militia was virtually born by the gathering together of various armed movements during the nationalist uprising of Irish republicans in Dublin on 24th April 1916 (an uprising known as Bloody Easter). Their goal was to obtain the independence of Ireland, then a member of the United Kingdom. It nevertheless had to put down its arms on 29th April, 1916. It again took up the offensive against British troops from January 1919 (considered the IRA’s founding moment). Ireland gained independence in 1921, with the exception of the six counties with a Protestant majority which formed Northern Ireland, still a member of the United Kingdom today. This division of the island was ands is unacceptable to the IRA, which entered into a struggle against the new independent state. Beaten, it again laid down its weapons in April 1923.

It gain drew attention in January 1939 when it organised a series of attacks in England, demanding the withdrawal of the British in Northern Ireland. The IRA carried out more operations in the following years but, lacking popular support, it had to once again suspend activities in 1962. At the end of 1969, it broke up into two rival factions: the Official IRA, Marxist, which renounced violence, and the Provisional IRA which began attacks against the British at the beginning of the 1970s. It was the beginning of a long war of which several thousand people were the victims. At the beginning of the 1990s a peace process was little by little put in place and, in 1994, the IRA announced a ceasefire followed by the complete cessation of military operations in 1997. This allowed Sinn Fein (the political wing of the IRA) to sign a peace accord with the Unionists (who were in favour of staying within the United Kingdom) in 1998. A very small minority of the IRA’s members nevertheless refused to accept this treaty and attempted to continue the armed struggle. In July 2005 the IRA ordered its members to put an end to armed struggle and it disarmed in the same year.

Iron collar

An iron collar fixed to a post or a pillory to attach to it, by the neck, a criminal condemned to public exposure.

Iron Curtain

This expression designates the defence system which was erected in Europe during the Cold War on the border separating the Western European states and the states of Eastern Europe, under Soviet influence. It most often took the form of electrified barbed wire, mine fields and watchtowers. The building of the Berlin Wall in 1961 represents the apogee of the construction of this system. It was wanted by the authorities of Eastern countries to prevent the nationals of these countries fleeing to Western countries. The expression, ‘Iron Curtain,’ was popularised by Winston Churchill during a speech he gave on 5th March 1946 at Fulton (USA) when he said ‘an iron curtain has been built on the European continent from Stettin to Trieste.’ Following the reform movements which took place in the USSR, the Hungarian authorities decided, on 2nd May 1989, to open its border with Austria. This was the beginning of the dismantling of the Iron Curtain, rendered totally obsolete by the fall of the Berlin Wall on 9th November, 1989.

Irredentism

A term derived from the Italian Italia irredenta (Italy unredeemed) which designates a nationalist political movement born in Italy in the 1870s. It called for the annexation by Italy of territories considered historically Italian, particularly those in which the Italian language was used. The majority of these territories were situated in the old Austro-Hungarian empire: Istria, Dalmatia, southern Tyrol, Trentino. At the beginning of the 20th century, Mussolini’s fascists appropriated the movement and extended its claims to French territories (Nice, Savoy, Corsica, Tunisia), to the island of Malta and southern Switzerland. Gabriele d’Annunzio (1863-1938) seized the town of Fiume (the present day Rijeka in Croatia) in 1919 in order to cede it to the Italian kingdom. He didn’t succeed. In our day, by analogy, the term is used to design any nationalist movement claiming the same principles of unifying or gathering together territories on a linguistic and cultural basis.

Ischemia

Decrease in the flow of blood to an organ. The lesions of the organ depend on the severity of the ischemia. Thus, the consequences of this reduction in blood flow at tissue-level can have reversible consequences when the ischemia is moderate or temporary, but a severe and/or persistent ischemia can lead to the destruction of tissue (necrosis, ulcers, infarction). When the myocardiac ischemia is silent (with no tell-tale signs) it is possible to detect it thanks to electrocardiogram.

Ischemic Pathology

Pathology caused by a blood supply deficiency in an organ and its resulting damage. Angina, infarction and cerebral vascular injury are typical examples of this pathology.

Islets of Langerhans

The Islets of Langerhans cells are pancreatic cells grouped together in small clusters that produce various hormones such as insulin.

ISO

The International Organization of Standardization) or ISO is a non-governmental organisation (NGO). It is constituted of the specialised national organisations of 160 countries. The ISO has the aim of producing international standards in the industrial and commercial domains, called ISO standards. These standards thus recognised are very useful for governments, economic organisations of every kind, regulatory authorities, professionals in the evaluation of conformity, the manufacturers, suppliers and consumers of goods and services, both public and private. The ISO headquarters are at Geneva. The ISO has established close to 19,000 international standards in the most varied domains. ISO 65 defines the conditions of transparency and independence for certification bodies. ISO 65 accreditation thus certifies the independence of FLO-Cert, the transparency of its activity, as well as the impartiality and effectiveness of its monitoring in terms of respecting fair trade regulations.

Isoforms

Different proteins resulting from alternative splicing of the same gene or proteins of close sequences from distinct genes.

isokinetic analysis

Isokinetic tests aim to evaluate muscular function in motion, at a constant speed, with a resistance that automatically adapts to the force deployed.

Isomer

Compounds which contain the same raw formula but which have different properties due to a different arrangement of atoms within the molecule.

isometric evaluation

Analysis of force development during a given effort.

Isotope

The atomic nuclei of chemical elements have a certain number of protons and neutrons. For instance, the hydrogen nucleus contains a single proton and no neutrons. But there are also two other “varieties” of hydrogen (i.e. isotopes) that stand out from the former owing to the number of neutrons in the nucleus: deuterium, whose nucleus is composed of a proton and a neutron, and tritium, whose nucleus only has one proton but also two neutrons. The different isotopes of the same chemical element are therefore atoms whose nuclei contain the same number of protons but a different number of neutrons. Since the number of electrons is equal to the number of protons, it therefore does not vary from one isotope to another. In other words, the isotopes of the same element often have identical physical and chemical properties. However, some can be unstable: this results in nuclear decay, turning the atoms into showers of radioactive particles.

In nature, an element is often composed of a mixture of isotopes. This is the case of carbon, for instance, which is essentially carbon 12 (6 protons and 6 neutrons) but is mixed with small quantities of radioactive carbon, i.e. carbon 14 (6 protons and 8 neutrons). It is its disintegration over time (it gradually disappears) that makes it possible to determine the age of a carbon sample in which it is present.

Isotope of Hydrogen

Italian Wars

Military expeditions sent by the kings of France to the Peninsula. It was Charles VIII who took the initiative to leave from Lyon in 1494, considering himself the heir to the House of Anjou’s rights over the kingdom of Naples.   His successor, Louis XII, the grandson of Valentina Visconti, the sister of the last duke of Milan born into this family, pursued the Italian ambitions of his predecessor. But despite Francis I’s victory at Marignan in 1515, the battle that was followed by the defeat of Pavia in 1525, French domination in Italy was short-lived. The country then passed under the imperial control of Charles V, a prelude to that of Spain which, moreover, benefited the interests – particularly territorial – of the Holy See. These wars ended with the treaties of Cateau-Cambrésis (2–3 April 1559).

Iteration

signifies the act of repeating a process habitually with the objective of reaching a desired goal or a required or necessary result.  Each repetition of this process is also called an iteration and the results of an iteration are used as a starting point for the following iteration.

IU/day or IU/month

International Units per day or per month.



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