L'adaptation à la vie arboricole chez les fourmis

Arboreal ants constitute one of the largest animal groups in the tropical forest canopy not just in terms of their individual number and overall biomass, but also in terms of diversity. Because the arboreal habitat has particular characteristics which clearly differentiate it from the ground, the ants' ecological success depends on developing adaptations designed to overcome the constraints peculiar to this environment in order to best exploit its resources. Although it is not always possible to identify all of the characteristics common to all arboreal ants species, those species said to be ‘dominant’ share morphological, physiological and behavioural traits which differentiate them from other ants. The most important difference is the type of food sources exploited. These dominant species feed principally on the nectar of the extra-floral nectaries of plants or on the honeydew of Homoptera. These products are extremely rich in sugary substances and low in nitrogen. The exploitation of these food sources has, then, repercussions on the growth and reproduction of ant colonies, given the importance of nitrogen as a limiting factor. Obtaining the necessary amount of nitrogen involves exploiting large volumes of liquid. From a purely morphological point of view, it is interesting to note that the digestive system of most of the dominant ant species has a modified proventriculus and a thin cuticle which means less need for proteins. These modifications permit individual foragers to transport large volumes of liquid by holding them in their crops in order to distribute them to the rest of the colony. The venom of many of these species also differs from that of other ants in that it lacks nitrogen. Dominant species have, thus, developed adaptations related to their feeding habits, lowering the need for nitrogen in individuals and, in this way, permitting the greater development of the colony. The exploitation of this type of food source is also facilitated by the type of nests constructed by the ants. Indeed, the elaboration of a nest independently of any structure provided by the plant offers numerous advantages, despite the important energetic costs involved. These types of nests allow the ant to (1) ‘choose’ the nest site and thus to install the nest on plants providing the best resources (extra-floral nectaries or Homoptera attendance) and (2) exploit a greater number of resources with lower energy costs by placing parts of the colonies near food sources. In addition, even if part of the sugary food substances are destined for the synthesis of molecules necessary to the survival and proper functioning of individuals, there is a large surplus. This surplus might indirectly reinforce these species' defensive systems on both an inter- as well as intraspecific level by serving as an energy source enabling individuals to have high level of activity and aggressiveness. The remaining arboreal species, which — in terms of diversity — make up the majority, do not share common traits which permit them to be clearly differentiated from terricolous species. Nevertheless, comparisons conducted within a genus show that certain arboreal species have developed adaptations to their way of life, and not only those species living in the domatia of ant plants, but also other, strictly arboreal species. As is the case for dominant species, the modifications observed originate especially in response to the two principal limiting factors in the arboreal habitat: available food resources and a limited number of nest sites.     

Jules Cotard: sa vie, son œuvre

Jules Cotard was a psychiatrist at the Vanves asylum. Described as a sharp observer and clinician, he also had a passion for clinical research. Jules Cotard was always ready to modify, question, or even abandon a hypothesis if clinical facts and scientific analysis made him deem it necessary to do so. He devoted most of his writing to “negation delirium”, (also known as “nihilistic delusion”): “Du délire hypochondriaque dans une forme grave de mélancolie (“Concerning hypochondriac delusion in serious melancholy”)” in 1880, “Du délire des négations (“Concerning negation delirium”)” in 1882, “Perte de la vision mentale dans une mélancolie anxieuse (“Loss of mental vision in anxious melancholy”)” in 1884 and “Du délire d’énormité (“Concerning delusions of enormity”)” in 1888. Long after his death, there was much controversy and debate about the existence of negation delirium. J. Séglas and J. Régis were the main contributors to the development and clarification of his work. Thus it is this most unusual of syndromes, Cotard’s syndrome, that has caused Jules Cotard to be part of the history of French psychiatry since the end of the 19th century.     

Le courant,facteur écologique et éthologique de la vie aquatique

Résumé Nous avons exposé dans ce travial l'état de nios connaissances sur le facteur courant, du double point de vue écologique et éthologique. Nous avons recherché les problèmes que pose cette étude et les moyens mis à notre disposition pour les résoudre.Avant d'entreprendre toute étude biologique sur le courant, il convient de bien étudier les caractéristiques mécaniques de l'eau en mouvement.Le courant est caractérisé le plus souvent par sa vitsse. Celle-civarie beaucoup suivant les points où on la mesure. Elle diminue vers la surface de l'eau et surtout contre le fond. Dans la végétation et derrière les obstacle, le courant est très faible: ces régions constituent les eaux-mortes. Ambhul (1959) a également en évidence une couche-limite presque immobile contre le fond.Le courant raréfie la nourriture des organismes, leur rend l'oxygène plus facilement utilisable.Au point de vue écologique, le courant est le facteur reposable de nombreuses adaptations. Le problème pour les animaux rhéophiles est de ne pas ne laisser emporter. Les animaux vivant en pleine eau (Poissons) ont une forme hydrodynamique, qui offre la moindre résistance. Le animaux benthiques, aplatis, sont plaqués contre le fond par une composante verticale de la poussée du courant (théorie de la poussée de Steinamann), ou évitent les effects mécaniques de courant, par leur taille petite ou leur forme, en se plaçant dans les eaux-mortes ou les couches-limites (Nielsen, Ambuhl).Les animaux se répartissent donc sur le fond suivant possibilitités par rapport au courant. On évalue quatitativement cette répartition en comptant le nombre d'individus se trouvant dans chaque zone de vitesse et en construisant le polygone de fréquence correspondant.Au point de vue éthologique, le courant est le fateur physique responsable du rhéotropisme. Beaucoup d'espéces s'orientent contre le contre le courant (rhéotropisme positif). Le déterminisme de cette orientation est mal connu. Des processus mécaniques et phisiologiques entrent en jeu suivant le cas. Le fait même de résiter au courant constitute aussi un genre de réponse à ce stimulus. On peut mesurer ce comportements par l'évaluation de la vitesse maximale supportée et des déplacements des organismes dans le courant.Nous avons affaire à un biotope complexe. son étude au laboratoire permet de sérier les questions, en simplifiant et contrôlant plus étroitement les conditions de milieu. Pour ce fai9re nous avons utilisé un appareillage spécial. Deux sortes de bacs à courant sont décrits:Des appareils à courant circulaire, pour lesquels nous avons établi une carte des vitesses aux aux différents point du fond. Un tableau de probabilité permet se savior si un animal fréquentee de préférence les zones à courant fort ou les zones à courant faible. Ces appareils permttent donc un choix organismes.Des appareils à courant retiligne oùle courant est plus régulier. Ils permettent des expériences sur la résistance au courant et la mesure des déplacements des organisme dans le courant.La vitesse du courant se mesure à l'aide de différents appareils souvent trop encombrants pour le laboratoire. Les principaux sont le tube de Pitot, utilisable pour les courant moyens à trés rapides, et le micromoulinet Beauvert, précis de 0 à 250 cm/s, utilisable surtout sur le terrain. Nous avons construit un balancier à curseur, muni d'une palette plongeant dans le courant. Un étalonnage permet de mesurer la vitesse de 0 à 60 cm/s dans toutes les parties des appareils utilisés au laboratoire. I1 permet également la mesure de la poussée du courant sur un objet plongé dans l'eau.Enfin Ambuhl (1959) utilise une méthode photographique valable au laboratoire pour les courants lents et trés lents.Nous avons enfin complété personnellement l'étude du courant en envisageant s aforce de poussée. Nous avons démontré que la larve de Micropterna testacea (Gmel.) (Trichoptera Limnophilidae) et son étui sont assimilables à un cylinder plongé dans le courant, de diamètre égal au diamètre antérieur de l'étui. Le régime d'écoulement de l'eau est toujours turbulent. Une formule donne la force F de poussée du courant en fonction de la vitesse V du courant et de la section S du cylindre plongé dans l'eau. Elle est voisine de la forme F = kSV². Les courbes données sur la figure 7 permettent de conaître la force supportée par une larve de Trichoptère plongée dans un courant de vitesse connue.Nous verrons dans une étude ultérieure que cette force semble constituer le stimulus actif dans le rhéotropisme de la larve de Micropterna testacea.

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Summary We have exposed in the preceding study what we know of the current as a factor, from the point of view both ecological and ethological. We have tried to make evident the problems which this study brings up and the means at our disposal for their solution.Before beginning a biological study of the current, it is necessary to make a thorough study of the mechanical characteristics of water in motion.The current is, as a rule, characterised by its speed, or velocity. The velocity is variable with the places of measure. It decreases near the surface and specially close to the bottom. In vegetation and behind obstacles the current is very slow. Dead water happens in these places. Ambuhl has also established the existence of a boundary layer almost motionless close to the bottom.The food of organisms is made scarce by the current which also makes oxygen easier to utilize.From the ecological point of view, the current is the factor responsible for many adaptations, specially of rheophilous animals which must resist being carried away. The swimming species (fishes) hydrodynamic shape allows them to resist the current. The benthic species are flattened against the bottom by a vertical component of the shove in the current (shove theory by Steinmann) or they may avoid the mechanical action of the current through their smallness or their shape and by placing themselves in the dead waters or the boundary layers (Nielsen, Ambuhl).The animals scatter themselves on the bottom proportionately to their capacity to resist the current. This distribution is quantitatively estimated by counting the number of organisms found in each zone of velocity and by drawing the corresponding polygone of frequency.From the ethological point of view, the current is the physical factor responsible for rheotropism. A great number of species set themselves against the current (positive rheotropism). The determinism of this orientation is little known. Mechanical and physiological proceedings come into play according to the particular case. The very resistance to the current is also a sort of answer to this stimulus. This behaviour can be estimated by evaluating the maximum velocity borne by the organisms and their moving about inside the current.We have to deal with a complex biotope, the study of which in the laboratory allows taking problems in their logical order, simplifying and controlling more narrowly the properties of the medium. For that study we have used special fittings. Two sorts of troughs or channels are described:An equipment for circular current, for which we have drawn up a chart indicating the velocity of each successive place on the bottom. A table of probabilities shows the prefered location of the animals, whether in zones where the current is strong, or in zones where it is slow. This equipment leaves to them the possibility of a choice.An equipment for rectolinear current. In these channels, the current is more regular. They allow of experiments on the resistance to the current, and appreciating the moving about of the organisms in the current.The velocity of the current is measured with the help of several appliances, often too cumbrous in the laboratory. The main ones are: the Pitot tube, useful in the case of mean to very rapid currents, and the Beauvert micromoulinet, shaped like small mill-wheel, with an accuracy of 0 to 250 cm/s, specially serviceable in natural surroundings. We have built a scale-beam fitted out with a traveller, and equipped with a paddle immersed in the current. Velocity, from 0 to 60 cm/s, is measured in all parts of the fittings used in the laboratory, by means of standardizing. The shove of the current on an object immersed in the water can also be measured.Lastly, Aambuhl makes use a photographic method sufficient in the laboratory for slow and very slow currents.We have personally supplemented our study of the current by an examination of its shove or thrust. We have showed that the larva of Micropterna testacea (Gmel.) (Trichoptera Limnophilidae) and its case are comparable to a cylinder in the current, the diameter of which is equal to the diameter of the forepart of the case. The waterflow is always turbulent. A formula supplies the force F of the shove, which force is a variable dependent on the velocity V of the current and on the section S of the immersed cylinder. The formula is very nearly F = kSV². The curves showed on figure 7 define the force that is borne by a larva of Trichoptera immersed in a current whose velocity is given.We shall see in a subsequent study that this force seems to form the active stimulus in the rheotropism of the larva of Micropterna testacea.

     

Paléopathologie : à propos de squelettes humains découverts à Poitiers (Vienne,France)

Palaeopathology: remarks about skeletons discovered in Poitiers (Vienne, France). Age, sex and stature of human fossils from a population decimated during an epidemic period are estimated. The prevalence of abnormalities and pathologies is compared with those of today’s population. Osteoarthritis is the most frequent pathology and this at different stage development. Osteoporosis and vertebrae compression are studied. The cases of important scoliosis are numerous. An abnormal vertebra is presented. A strange lesion on the ilium of the left coxa is discussed. Some hypotheses are formulated concerning the mode and the hygiene of life of this population. To cite this article: O. Boeuf, P. Alberti, C. R. Palevol 2 (2003) 169–180.     

Hommage à rené delépine à l'occasion de son départ à la retraite

A tribute to René Delépine on the occasion of his retirement. The career of René Delépine is reviewed on the occasion of his retirement. When he was a student, a meeting with Jean Feldmann led to a lifelong inclination towards phycology. Eventually appointed to the position of assistant professor at the University of Paris-VI (University Pierre-et-Marie-Curie), René Delépine worked and published primarily on the taxonomy of antarctic and subantarctic marine algae but he was also interested in seaweed aquaculture and utilizations. After organizing the national colloque ValVA (Valorisation des végétaux aquatiques), he became increasingly involved in the commercial application of seaweeds. His main activity, however, remained university teaching for which he was always enthusiastic, especially for teaching in the field and on the subject of the utilizations of algae. A list of his publications is given at the end of this article.     

La fracture de verge à Dakar. à propos de 25 cas

Objectives

To describe the epidemiological, clinical and therapeutic characteristics of penile fracture in the department of Urology-Andrology of h?pital général de Grand Yoff, Dakar, Sénégal.

Materials and methods

We reviewed the medical records of cases of penile fracture managed at the h?pital général de Grand Yoff from January 2001 to December 2011. The data of interest were: age at diagnosis, geographic origin, clinical presentation, surgical findings, treatment and outcomes.

Results

In ten years, 25 cases of penile fracture were found with an average of 2,5 cases per year and patients mean age of 36 years with 22 and 60 years as extremes. The circumstances of occurrence were mainly forced manipulation (52%) and coitus (32%). Pain associated with penile curvature, swelling localized to the penis or extending to the pubis or the perineum were the major clinical findings. A prompt emergency (mean time for providing care was 2 hours ranging from 45 minuts to 2 days) surgical explorationwith suture of the albuginea of the corpus cavernosum was the treatment in all cases.

Conclusion

Penile fracture is a relatively uncommon urological emergency in our setting. The diagnosis is easy, mostly based on clinical examination. A prompt and appropriate surgical management is the key to cosmetic and functional outcomes.     

Imprégnations rapides à la Nigrosine applicables à la micro-ecologie des surfaces

Summary The ecology of primary biological coatings (fouling films) is an important aspect of benthic ecology in general. Life in a fouling film is, to a large extent, governed by physico-chemical laws of contact surfaces and surface tension. These laws apply also to the microecology of the mesopsammon and surface microplankton. The conditions common to these ecological situations enforce common characteristics, both morphological and physiological, upon the organisms which inhabit them. Many of these organisms are therefore subject to certain general techniques.Nigrosin is employed as an impregnating agent, and the speed of activity of the micelles of nigrosin is under the control of 1) the colloidal nature of the medium, and 2) alteration of cytoplasmic structures by the action of formalin added to the solution as a fixative.The stain blackens a variety of organites having a filamentous ultrastructure: cilia, flagella, trichocysts, rhabdites, cnidocysts, spiny processes of thecae and shells, capsules, cuticles and cuticular setae. The excess nigrosin surrounding the specimen may be removed completely by simple washing.Two particular situations are discussed: that of microbiocoenoses which develop at the point of contact of water and air (for example, bacterial films) and that of glass slides immersed in water with a view to studying the organisms which colonize surfaces in a particular habitat.The method has been applied also for studies of plankton in general, to demonstrate the liberation of flagellate bodies by certain algae, and for preparation of mounts of various organisms such as rotifers, gastrotrichs and nematodes. The method is very useful for quickly obtaining a comprehensive picture of the protozoan fauna in ecological studies.     

Les sites acheuléens des grottes la Terrasse et du Coupe-Gorge, à Montmaurin,Haute Garonne,France

The huge karstic network of Montmaurin is located at the western end of the chain of the Petites Pyrenées, and contained several caves escavated by Louis Méroc and his team to 1946 at 1961. Among the eight caves that have escaped the exploitation of quarrymen the richest in stone industry and fauna are the caves la Terrasse and le Coupe-Gorge which are Acheulean sites. The techno-typological and petro-archaeological study conducted during this research shows the specificities inherent to the Montmaurin caves. The lithological procession is composed of pebbles quartzite lydian quartz etc. that come from the tributaries of the Garonne and pre-Pyrenean flint. The acquisition territories of mineral resources are more or less vast, from a hundred meters to about 80 kilometers. The techno-typological characteristics of the Montmaurin cave's industries testify a technical and economic behavior oriented towards production and consumption activities in situ. Differential management of lithic resources is observed, which echoes both the technical requirements imposed by the debitage methods employed and the knapping skills.     

Hypospadias: conséquences psychosociales, urologiques, sexuelles et reproductives à l’âge adulte

Hypospadias is a developmental abnormality. The most obvious feature is an ectopic urethral meatus situated on the ventral aspect of the glans or the penis, or on the scrotum or perineum. This defect occurs in about 1/250 to 1/300 live births. Surgical repair is designed to allow micturition in a standing position, enable normal sexual function and to give the penis as normal a cosmetic appearance as possible. This malformation and its treatment have repercussions on psychosocial development, urinary and sexual function, and reproduction. The literature distinguishes three populations of patients.

1. Patients who have corrective surgery during childhood. The most frequent urological complications are fistulas, diverticula, urethral stenosis and micturition difficulties. The risk of infection is not increased. Psychosocial development is usually not affected, and maturation and early sexual awareness are normal. However, these patients have greater difficulty in making contact with the opposite sex. In adulthood, problems of erection and ejaculation are frequent.
2. Patients who have corrective surgery in adulthood. The urological results of surgery are less favourables and complications are more frequent than in children. No data about sexual function are available.
3. Patients who do not have surgery. Although there are no specific studies, these patients do not appear to differ from those operated as children in terms of micturition difficulties, psychosexual development and sexual function.
4. Reproductive capacity. There is usually no disorder of the hormones involved in testicular function (gonadotropins, androgens) in either children or adults. However, clinical, histological and spermiological factors may affect fertility.

The frequency of infertility in the population of men who have undergone corrective surgery for hypospadias during childhood has not yet been evaluated.     

Introduction à l’anthropologie clinique

This paper discusses the concept of clinical anthropology. It recounts how an anthropological school of thought emerged in psychiatry and clinical psychology. Nowadays, that school spans the fields of philosophical anthropology, medical anthropology, cultural psychiatry, anthropological psychology, and clinical anthropology. After providing a conceptual and historical definition, we briefly introduce the ideas of the psychiatrist and philosopher, Ludwig Binswanger. In 1930, he became the first to introduce anthropological research into psychiatry, emphasising the a priori difference between homo natura and existence. Finally, we outline the development of phenomenological anthropology in Europe, with reference to the major philosophers and psychiatrists of the second half of the twentieth century.