The range of distances from a star at which water can exist in liquid form on the surface of a telluric planet with a sufficient atmosphere. Depending on the distance, a telluric planet can have its surface water in gaseous or solid form respectively.

Collection of organs which are involved in the physiological process of producing blood cells (haemocytes).

Sensory cells that are situated on a membrane separates the cochlea into two parts. They are put into movement by the sound vibrations in accordance with certain frequencies: those closest to the base of the cochlea are sensitive to high-pitched sounds; those situated in the last part of the spiral are sensitive to low-frequencies (low-pitched sounds). The vibrations received by the cilia that these cells are equipped with are transformed by the auditory nerve into electrical signals that can be interpreted by the brain.

Cavities in which hairs develop by multiplication of cells producing keratins. They are also associated to the sebaceous gland which produces sebum (lubricant).

From the Arab word meaning ‘permitted,’ ‘lawful’. It designates what is permitted for Muslims, notably in terms of guidelines for food consumption.

Former professor of English language and literature at the ULg. His publications include Histoire politique et littéraire du mouvement flamand (1894) and the Introduction à la littérature française et flamande de Belgique (1921).

muscles at the back of the thigh, starting at the pelvis (at the ischium) and connecting to the tibia. They play a crucial role in running.

Former professor of the history of French literature, and of French grammar at the UCL. He co-directed with Gustave Charlier the Histoire illustrée des lettres françaises de Belgique (1948 and 1959) and he edited La Légende d'Ulenspiegel (1959) as well as the complete poetry of Maeterlinck (1965).

The harmonics of a fundamental frequency f₀ are multiples of this frequency.
For instance, a stimulation frequency f₀ of 10Hz (fundamental frequency, also called first harmonic); the harmonics of this frequency are 20Hz (second harmonic), 30Hz (third harmonic), etc.

Haussmann was a high-level French bureaucrat and prefect of the region of the Seine from 1853 to 1870. In this capacity, and at the request of Emperor Napoléon III, he undertook the urban renewal of Paris. Many boulevards and avenues, most of them rectilinear, were created, along with public parks and gardens, all of which followed strict urban guidelines affecting the height of buildings and the styles of façades. Haussmann also rebuilt the system of water distribution and the sewer system. This radical transformation of Paris occasioned the destruction of around 18,000 houses. He became a Senator in 1857 and was eventually named a baron.

One of the main global actors in fair trade. It is also a branch of the international association Fairtrade labelling Organizations International (FLO). Max Havelaar is not the name of the association’s founder, but the title of a novel published in 1860 in the Netherlands by Eduard Dowes Dekker, under the  pseudonym of Multatuli. In it the author denounces the conditions of the peasants on the island of Java (also part of the colony of the Dutch Indies, the current Indonesia), oppressed and exploited by the local Javanese authorities, with the complicity of the colonial authorities. Max Havelaar (MH) is a fair trade certification body: as such MH neither sells not buys anything. It awards its label only to the products which meet the international criteria of fair trade, dealing mainly with good production conditions, a fair price, respect for the environment, etc. Respect for the fair trade criteria is monitored by a team of fifty or so inspectors, which check some 500 producer and plantation organisations in the light of 250 evaluation criteria.

the Haversian lamellae are layers of concentric bone (osteon) that are formed during bone growth that surround the Haversian canals. These canals contain blood vessels, lymph vessels and nerves.

Human Development Index, developed by the Nobel-prize winning Indian economist Amartya Sen and his Pakistani colleague Mahbub ul Haq within the UN Development Programme (UNDP). This index takes into account three criteria: life expectancy at birth, adult literacy rate and gross domestic product. The HDI is thus a figure of between 0 (poverty) and 1 (ideal)

Alternative investment funds. The verb 'to hedge' means 'to cover'. Hedge funds are usually not listed on the stock exchange. They seek maximum investment performance through the use of derivative products.

a Belgian francophone writer – his real name being Frédéric Van Ermengem – who was born and died in Brussels. He has remained one of the major representatives of Belgian literature of the fantastic, as is witnessed by his novel, Mélusine (1920), inspired by a Medieval legend in which a character is condemned to metamorphose each Saturday into a woman-snake: here though, in a strange garden devoid of any vegetation, readers discover themselves in the presence of a naiad whose ‘yellow and glowing body is composed of heavy coins with cemented joints.’ But besides these works where dreamlike impressions predominate, close to Dadaism and Futurist currents, Hellens was also a defender of Belgian literature in the French language, notably through the journal Le Disque Vert which he founded in 1922 and which never departed from a great eclecticism. And it is not his slightest merit having discovered the poet Henri Michaux.

A co-factor containing an atom of iron which serves to host a diatomic gas (often dioxygen O₂) at the centre of a large organic ring called prophyrin.

The heme synthetase (also known as ferrochelatase) is the enzyme which condenses porphyrin and the iron atom to form the heme. It acts in the presence of an iron donating co-factor.

After cellulose, this is the second component of plant cells. It plays a role notably in forming a bridge between fibers and cellulose. 

A fluid which plays the role of blood in arthropods (insects, spiders, etc.).

An Afro-American guitarist and one of the first electric guitar virtuosos. In 1966 he went to London and formed the rock group The Jimi Hendrix Experience. His passionate music shook up in particular the fields of the Woodstock festival inn 1969. He died in 1970, aged twenty-seven.

Hepatic insufficiency is a consequence of cirrhosis of the liver, when the organ can longer perform its multiple functions. Signs of decompensation appear when more than 75% of the liver isn’t functioning anymore.
The symptoms are as follows:
- icterus: yellow discoloration of the skin (jaundice)
- ascites: accumulation of fluid in the abdomen.
- haemorrhaging: due to an insufficiency in the production of blood coagulation factors. Severe digestive haemorrhaging can also occur when varices rupture in the oesophagus, resulting in local hypertension caused by the cirrhosis.
- asthenia and a drop in the immune defence system by a fall in the production of proteins required for this function.
- encephalopathy:  neurological manifestations (confusion, convulsions, coma) associated with the accumulation of ammonia in the blood. This product of the degradation of proteins can no longer be detoxified by the liver and disrupts the functioning of the brain.

Primary liver cancer*, which almost always develops as a result of cirrhosis or chronic viral hepatitis B or C, after a period of evolution of two to three decades. The cancer isn’t the result of metastases but, instead, grows locally in the liver, where it eventually causes end-stage decompensation.  The only real curative treatment is a liver transplant.
On a global level, it is one of the most common cancers.

*Primary cancer means that the tumour originates in the liver itself, as opposed to ‘secondary’ cancer, which refers to the metastases in the liver originating from another cancer, which is frequently the case.

Hepatocyte is the name given to the cells in the liver. They are extremely active cells that fulfil numerous roles in the body: they intervene in the metabolism of carbohydrates and lipids, the recycling of haemoglobin, bile production, the production of blood coagulation factors and the proteins necessary for the immune system, and the detoxification of toxic products, alcohol and a great many types of medication.

The wife of Zeus and the First Lady of Olympus; the protector of marriage and women.

The hero of ‘the Twelve Labours’, and whose Latin equivalent goes by the name of Hercules.

A name derived from the Greek hairesis meaning ‘preference, special  opinion’ and designating a doctrine which issues from within the Catholic Church but which it condemns as conflicting with dogma.

Yhe god of transit and mobility, on the Earth as much as between the world of the living and that of the dead.

A family of DNA viruses (which have DNA in their genetic composition) that cause many maladies in animals and in humans. Among humans, there is oral and genital herpes, chicken pox, Herpes zoster, infectious mononucleosis, etc.( See A vaccine against infectious mononucleosis)

Greek poet (8th – 7th century before our common era), the author of Theogonia, a work which features the oldest interpretation of the creation of the world and the genealogy of the divinities of the Hellenic pantheon. He also remains known for his Works and Days, which informs us about the agrarian practices of his era.

German novelist, poet, painter and essayist, who then became Swiss, He won the Nobel Prize for literature in 1946 partly for his great work, The game of glass beads, from 1943.

From the Ancient Greek eurisko, meaning 'I find'. Heuristics are descriptive rules that can be logically linked together in a problem solving mode (Heuristics-based decision support systems). In contrast to algorithms, or sets of equations, aimed at providing an analytical solution (Model-based decision support systems).

Sub-category of the arthropods, which notably includes insects.

A cursive form of the hieroglyphic system. It is the basic system that all scribes use, since the hieroglyphic system is reserved for an elite. Hieratic script allows scribes to write upon things such as wood, papyrus or pottery shards (ostraca). The system was mostly used in administration or in daily life, and continued to be commonly used up until the seventh century B.C.E., when it was further simplified in order to produce the demotic script. A scribe who had to inscribe hieroglyphs upon a monument would recopy them based on notes written in hieratic, or by using painting at an earlier time. Another scribe might make corrections to the work of the first, and at the end of this process, hieroglyphs would be inscribed in stone.

A character in the most ancient form of Egyptian writing (used from the fourth millennium B.C.E. through the fourth century C.E.). The hieroglyphic system is figurative, but it combines phonetic and ideographic values in order to transcribe several levels of language, whether phonetic or semantic. In this way, a hieroglyphic sign can have different functions according to its place within a single word. The primary function of the system is to establish individuality, especially with regard to the existing political power, and this explains the monumental character of hieroglyphic inscriptions. Hieroglyphs have to do with kings or with the sacred, and these signs have been simplified in order to function within a simpler system of writing (the hieratic system or the demotic one) – one used more commonly, or used for writing on supports that were less prestigious than stone, such as papyrus. The hieroglyphic system was deciphered in 1822 by Jean-François Champollion.

An Egyptian scribe who was capable of understanding hieroglyphs and making new inscriptions.

An analytical method of separating components that presents different chemical properties. A sample (a mixture of pigments extracted from sediment, for example) is pushed by a liquid (mobile phase) and kept for a stationary phase which causes a pressure, and separates the components according to their chemical properties creating peaks of different kinds. By comparison with reference standards, the nature of each of these peaks can be identified and studied.

A cortical structure situated in the median region of the temporal lobe which plays a vital role in memory and learning.

When an allergic individual is exposed to an allergen (a substance likely to cause an allergy, for example pollen grains), the immune system of the individual in question releases different substances, known as mediators, like for example histamine which are responsible for the appearance of symptoms related to the allergy. In serious cases, the release of a large amount of histamine can cause an anaphylactic shock, that is to say a sudden and drastic lowering of blood pressure.

Science of the study of biological tissues. It is used to study the structure of living organisms and the interactions between their functional elements. It has a very important role in the exploration of pathological processes and their effects.

A family of proteins that DNA winds around in the nucleus, thus compacting it into a much smaller size.

The art of writing history. Depending on the circumstances, this term can refer to historical work relating to a given era, and even to the reflections of historians on the actual writing of history.

HIV is a virus that weakens the human immune system. The name was chosen in1986. The virus was identified and isolated by a group of French researchers at the Pasteur Institute.

An English philosopher whose thinking, primarily presented in his work Leviathan, was deployed in order to distinguish the state of nature from the political state. Humans living in a dog eat dog condition, it was necessary to control original social violence by a strong power, which does not stem from God but from human beings themselves, concerned to curb this law of the jungle which threatened to devour them one after the other. From this springs a monarch – or a State – looming over a society neutralized by an ‘(imposed) non-aggression pact.’

A geological era extending back to 10,000 years ago. It was the last interglacial period of the quaternary, the most recent geological period of the Cenozoic era (66 million years ago to the present day), which is itself the most recent geological era after the Paleozoic era (541 million to 252 million years ago) and the Mesozoic era (252 million years to 66 million years ago).

A term used in zoology to designate a specimen which has enabled the definition and description of a given category in the classification of living organisms.

The capacity of an organism to maintain its different constants at normal levels in order to remain in balance.

Mechanism whereby a fragment of DNA inserts itself into a part of the genome where it shares a similar or identical sequence.

Each of our genes exists in two copies, one inherited from the father, the other from the mother. Therefore eye-color is the result of two genes coding eye color... which do not necessarily code for the same color. It is said therefore that the same gene (the one coding color) exists in two forms (or alleles). When an individual possesses two similar variants of the same gene ( both of them code for the color blue for example), it is said to be homozygous. If the gene is present in two different variants, it is said to be heterozygous.

The cancer cells have oestrogen and progesterone receptors.

HPLC is one of the most common techniques used in chemical analysis laboratories. It makes it possible to identify, separate and dose chemical compounds in a mixture. Its great precision enables trace searching and it is possible to couple it with mass spectrometry.

In cosmology, the Hubble constant is the constant of proportionality between the distance and the speed at which distant galaxies are moving further apart from us. The Hubble constant gives the local local expansion rate of the universe. The further away an object is, the more quickly it is moving away from us. But measurement of the Hubble constant remains delicate because of the difficulty associated with precisely calculating the distance of theobserved objects.

According to the commonly-accepted model, the Hubble constant is currently estimated at around 73 kilometers per second per megaparsec (73 Km/s/Mpc). This means that a body at one megaparsec from an observer is moving away at a speed of 73 Km/s. A body at10 Mpc from an observer is moving away at 730 Km/s.

A Dutch historian specialised in the medieval period. Homo Ludens (1938) is a ground-breaking work on which the different contributors to War and Games based their work. In this work, Johan Huizinga deals with the influence of game on European culture. He saw game as a cultural phenomenon, presenting it as a direct contribution to the development of culture. Civilization was born and developed like a game; human culture emerged from the game and has the characteristic of a game.

A movement of thought which, starting from Italy, developed in Europe during the Renaissance period (from the end of the 15^th to the beginning of the 17^th centuries). The humanists of the Renaissance were erudite, with a thirst for knowledge, a will to make it progress and transmit it in an accessible manner. They affirmed their confidence in the human being, who they placed at the centre of their preoccupations and whose personal development they looked for. The Humanist movement reconnected with the values, the philosophy, literature and art of classical Greco-Roman Antiquity, considered as the foundation of knowledge. But it also proposed new values, rooted in reason, free will, independence, tolerance and an openness of mind. Thanks to the invention of printing (by the German Gutenberg, around 1454), humanism spread throughout the whole of Europe and in particular favoured the emergence of the Protestant Reformation. Amongst the first humanists were Petrarch (1304-1374), Leonardo de Vinci (1452-1519), Giovanni Pico della Mirandola (1463-1494), Erasmus (circa 1467-1536), Machiavelli (1469-1527), Thomas More (1478-1535), François Rabelais (1494-1533) etc. A very great number of the thinkers of later periods staked a claim to this current of thought or can be termed humanists. Amongst them are: Descartes, Montesquieu, Victor Hugo, Emile Zola, Gandhi, Albert Camus, Albert Jacquard, etc.
Modern humanism involves currents of thought which expound the absolute primacy of the human being, the ultimate reference with which to approach other potentially competing values. The flowering of the human being, balanced and in solidarity with others, must be looked for beyond any subjugation and independently of any supernatural reference, all the more so in that human beings are capable of evolving by themselves in a positive manner. Certain contemporary intellectuals nevertheless warn against a possible drift of humanism, which would lead to the human being being considered as a ‘supreme being’ authorised to appropriate nature and exploit it without limit.

A Dutch astronomer and mathematician, one of the first real representatives of the modern scientific spirit, both as an experimenter and as a theorist, and author of the first complete treatise on the calculation of probabilities. In astronomy Huygens invented a combination of lenses which eliminated chromatic aberration, and doubled the length of astronomical telescopes, which in addition increased their magnifying power. This enabled him to notably discover the rotation of Mars and its period. He was amongst the first to point out that the stars were other suns, much further away from ‘ours’. He estimated, with remarkable precision for the period, the distance between the Earth and the Sun. In mechanics, he established the theory of the pendulum, which he used to regulate the movement of clocks. We also owe to him the use of a hairspring for watches, the conception of centrifugal force and the definition of the moment of inertia.

Often used to treat wrinkles by means of injection, hyaluronic acid is first and foremost a glycosaminoglycan that is present in synovial fluid. It is one of the main components of the extracellular matrix. It is currently used to treat osteoarthritis of the knee.

A pathology resulting from the absence of development of the cerebral hemispheres which are replaced by pockets containing cerebrospinal fluid.

An organic substance only composed of Carbon and Hydrogen atoms (for example, petrol, coal, natural gas, etc.). It is called saturated when the chain it is made up of is composed entirely of single bonds. If it contains double or triple links, it is called unsaturated.

A severe neurological anomaly which consists of the cerebral ventricles containing the cerebrospinal fluid increasing in volume.

procedure which consists of fixing hydrogen atoms on the double bonds of unsaturated fatty acids. That raises their degree of saturation and melting point. It is this procedure in particular which allows liquid vegetable oils in their natural state to be rendered semi-solid, for example from the point of view of using them in margarines. These fats are abundantly used in the agrofood sector (sandwich spreads, chocolate, ready made meals, pastries, etc.).

A chemical reaction which consists of adding a hydroxyl group (-OH) to a molecule. In the case of vitamin D, after it has been integrated by means of food for example, it is transported to the liver where it is hydroxylated by the enzyme 25-hydroxylase, which fixes a hydroxyl in the place of the H of carbon 25, forming 25-hydroxy vitamin D also called calcidiol.

Similar to a “tongue”, although it does not have the same function as in humans. It supports the branchial basket. It allows the fish to vary the volume of its mouth to adapt the force of its food intake. 

An abnormally high concentration of sugar in the blood.

An endocrine gland located at the front of the neck, the thyroid regulates various hormonal systems thanks to the secretion of two hormones, triiodothyronine (T3) and thyroxin (T4). Hyperthyroidism is caused by an excessive concentration of one or both of these hormones in the blood. The most frequent symptoms are tachycardia, diarrhea, weight-loss and insomnia. The opposite symptoms are associated with hypothyroidism including tiredness, memory loss and weight increase.

Reduction in hearing ability.

Under the epidermis and the dermis, the hypodermis is the deepest layer of the skin. It serves as an interface between the dermis and the moveable structures situated underneath it (muscles, tendons). It also protects the body from physical blows, temperature variations and acts as a store of adipose (fat).

Pathological reduction in the lipid level in the blood.

Since the Council of Ephesus (431) this expression designates the union of the divinity and humanity in the person of Christ.

Term which comes from the Greek hupo: under, and Oxus: oxygen. A reduction in the quantity of oxygen distributed by the blood to the tissues.