875 research outputs found
Podocoryna martinicana, a new species of athecate hydroid (Cnidaria: Hydrozoa: Hydractiniidae) from the Caribbean
No full textGalea, Horia R., Ferry, Romain (2013): Podocoryna martinicana, a new species of athecate hydroid (Cnidaria: Hydrozoa: Hydractiniidae) from the Caribbean. Zootaxa 3710 (6): 578-590, DOI: 10.11646/zootaxa.3710.6.
Podocoryna M. Sars 1846
No full textGenus Podocoryna M. Sars, 1846Published as part of Galea, Horia R. & Ferry, Romain, 2013, Podocoryna martinicana, a new species of athecate hydroid (Cnidaria: Hydrozoa: Hydractiniidae) from the Caribbean, pp. 578-590 in Zootaxa 3710 (6) on page 579, DOI: 10.11646/zootaxa.3710.6.4, http://zenodo.org/record/21820
Hydractiniidae L. Agassiz 1862
No full textFamily Hydractiniidae L. Agassiz, 1862Published as part of Galea, Horia R. & Ferry, Romain, 2013, Podocoryna martinicana, a new species of athecate hydroid (Cnidaria: Hydrozoa: Hydractiniidae) from the Caribbean, pp. 578-590 in Zootaxa 3710 (6) on page 579, DOI: 10.11646/zootaxa.3710.6.4, http://zenodo.org/record/21820
Podocoryna martinicana Galea & Ferry, 2013, sp. nov.
No full textPodocoryna martinicana sp. nov. (Pl. 1, 2; Fig. 1; Tables 1, 2) Material examined. Martinique, Case-Pilote, 14.638553 °, - 61.139591 °, 18.ii.2013, 10 m: one shell carrying a fertile hydroid colony (holotype, MHNG-INVE- 83148), about 50 newly released medusae (paratype, MHNG- INVE- 83149), as well as 49 additional shells with hydroid colonies (paratype, MHNG-INVE- 83150). Description. Colonies live exclusively on gastropod shells inhabited by the hermit crab Iridopagurus caribbensis. The hydrorhiza is an encrusting, nearly continuous mat of perisarc-covered stolons, generally not overlaid by coenosarc externally, except for some rare instances in which the latter spreads for a limited extent around the base of some nutritive polyps. The perisarc is rather thin, translucent, straw-colored. Spines are absent. Zooids arise directly from hydrorhiza and are of three types: gastro-, gono-, and tentaculozooids. Gastrozooids are stout, tall (1.0–5.0 mm high), columnar (0.4–0.8 mm wide), generally 1–6 in number (but up to 9 were observed 2) in a linear row along the inner lip of the host shell (Pl. 1 F–H). They are provided with up to 86 filiform tentacles with solid endodermal cores, arranged in 2–5 closely-set whorls, held in various attitudes, and irregularly bent or curved. Aberrant, two-headed polyps (Pl. 1 I) were irregularly found among the colonies examined. The gastric cavity is lined with prominent longitudinal ridges and villosities, especially visible in polyps with the mouth open wide, or in those turned inside-out (Pl. 1 L). Gonozooids, more numerous (up to 48) and much smaller than their nutritive counterparts (0.5–1.7 mm high, but up to 2 mm in full extension, and 0.2–0.3 mm wide), occur typically on the rim of the upper lip of the host shell (Pl. 1 E, G, H). Their dome-shaped hypostome, which does not open externally into a mouth, is encircled by a whorl of 4–9 tentacles reduced to globular, mere stumps (Pl. 2 H). Aberrant, two- (Pl. 2 I) or even three-headed polyps may be found among the common ones. Up to 30 gonophores are borne on short stalks arising from a budding zone 1. The role of the vents was to allow for the input of oxygenated water, carrying food items, and to prevent potential predators from reaching the hydroids. 2. Their number varies according to the age of the colony and the size of the inhabited shell. proximal to the tentacular whorl (Pl. 2 G). Young gonophores are more or less spherical, while the older ones become more pyriform. All are enveloped in a thin, transparent, membranous sheet ruptured by pulsation of the gonophore before release from the parent polyp. The gonophores are liberated as free-swimming medusae. Medusa buds are provided with four well-developed tentacles, coiled up in the subumbrellar cavity (Pl. 2 J). PLATE 1. Hermit crabs either resting burrowed in sand (A) or foraging (B). Ventral (C), lateral (D), and dorsal (E) views of three crabs, to show the position of gastro- and gonozooids. Encrusting hydrorhiza and gastrozooids on the inner lip of a shell (F). Shell apertures colonized by hydroids (G, H). Double-headed gastrozooid (I). Details of the insertion of tentacles (J) and their solid endodermal cores (K). Inside-out gastrozooids showing the characteristic longitudinal ridges lining their gastric cavity (L). Scale bars (in mm): 0.5 (J, K); 1.0 (F–I); 2.0 (C–E); 2.5 (L); 3.0 (A, B). PLATE 2. Fertile gastrozooids (A–C). Tentacluzooids (D). Portions of outer lip of a shell showing gonozooids (E, F). Overview of a gonozooid (G) and detail showing its withered tentacles (H). Double-headed gonozooid (I). Young (J) and nearly liberable (K) medusa buds. Newly liberated medusa seen both laterally [with incident (L) and transmitted (M) light], and in oral view (N). Detail of the manubrium (O). Aboral view of umbrella showing the four interradial pigmentary spots (P). Scale bars (in mm): 0.05 (O, P); 0.1 (K–N); 0.3 (H, J); 0.5 (B, C, E–G, I); 1.0 (A, D). FIGURE 1. Hermit crab inhabited shell colonized by hydroid (A). Shells with removed hermits to show the arrangement of the various polyps around their apertures (B, C). Group of gastrozooids (D), of which one (left) bears medusa buds. Gastrozooids with medusa buds (E, F), gonozooids (G, H). Newly-liberated (I, J), 1 -day (K), 2 -day (L, M), and 3 -day-old (N–Q) medusae. Cnidome (R) of the gastro- (R 1), gono- (R 2), and tentaculozooid (R 3), as well as of the medusa bud (R 4). Scale bars: 10 µm (R), 300 µm (H–Q), 1 mm (D–G), 3 mm (A–C). Drawings by H.R.G. (B–G, I–R) and R.F. (A, H). Tentaculozooids (Pl. 2 D) are present in about 45 % of the specimens inspected. Up to 16 of these slender structures may be scattered among each colony, though they differentiate mostly on their edges. They are very extensible (0.5 –5.0 mm long) and arise from a broadened base given off from the perisarc meshwork, then taper gradually toward tips. Newly liberated medusae are bell-shaped, approaching the globular, about 0.3 mm high and wide (Pl. 2 L, M). The mesoglea is uniformly thin. An umbilical canal is present, but it is soon lost during growth. The exumbrella displays a moderate number of scattered nematocysts, and there is sometimes a slight apical depression (Fig. 1 K). The manubrium is fusiform to tubular, extending to about halfway to velar aperture, and there is no peduncle. The mouth is simple, square when open wide (Fig. 1 J), provided with four perradial, short lips crowded with fusiform nematocysts (PL. 2 O). There are four moderately narrow radial canals, a rather inconspicuous ring canal, and four perradial bulbs, each bearing a single filiform tentacle of equal development (Pl. 2 N). Ocelli are absent and the velum is broad (Fig. 1 L). No signs of gonad formation could be noted at this stage. Medusae raised for three days in natural conditions did not develop much compared to the newly-released ones. They attained about 0.5 mm in height and width, and their gonads were still not formed 3. In life, the body of gastrozooids is generally orange in color (Pl. 1 G), though about 3 % of the inspected colonies had polyps that exhibited various shades, ranging from dark brown to purple. However, their distal part, including an area below the origin of tentacles, these structures, and the hypostome, are always of a bright, white tinge (Pl. 1 J, K). The gonozooids harbor the same colors as their feeding counterparts (Pl. 2 F). The medusa buds are rendered conspicuous through the bright white coloration of the distal part of their tentacles, marginal bulbs, and the four interradial white spots on the manubrium (Pl. 2 L–N, P). The tentacles of both the hydroid (Pl. 1 K) and medusa exhibit a very characteristic, closely set, alternating light and dark banding pattern. Nematocysts 4: the categories of capsules occurring in the hydrorhiza, the various polyps and the medusa buds, together with their dimensions, are summarized in Table 1. There are 3 size classes of microbasic euryteles in the polyps (small, medium sized, and large capsules), as well as an isorhiza 5. The medusa buds are provided with medium sized microbasic euryteles (comparatively wider then those of the gastrozooids), large microbasic heteronemes 6 (more fusiform than the euryteles of polyps), and desmonemes. Remarks. One of the most striking features of Podocoryna martinicana is found in its gastrozooids, whose considerable number of tentacles, arranged in multiple closely set whorls, is rather uncommon within the family Hydractiniidae. Only a few taxa exhibit such a feature: up to 40 tentacles were reported in both Hydractinia minoi (Alcock, 1892) (see Hirohito 1988) and Hydractinia proboscidea (Hincks, 1868) (see Bouillon et al., 1997, as Hydractinia calderi sp. nov.); up to 50 in Schuchertinia epiconcha (Stechow, 1907) and Hydractinia spiralis (Goto, 1910) (for both, see Hirohito 1988); up to 60 in Hydrissa sodalis (Stimpson, 1858) (see Hirohito 1988); and up to 91 in Hydractinia multitentaculata Millard, 1975 (see original description). However, the gonozooids of H. sodalis bear fixed sporosacs, while those of S. epiconcha, H. multitentaculata, H. proboscidea, and H. spiralis produce medusoids. In contrast, H. minoi grows in association with scorpaeonid fishes, and its medusa buds are devoid of mouth and its associated appendages. Based on the list of valid species of hydractiniid hydroids compiled by Schuchert (2013), and upon a thorough search of the relevant literature, it appears that only 22 taxa 7 reproduce through free-living, feeding medusae. For comparisons of both their hydroid and medusa stages, see Table 2. Since only young, sexually immature medusae were obtained for P. martinicana, the differences to other species described exclusively from their pelagic stage are sometimes difficult to establish, mainly due to the scarcity of morphological features displayed, further confounded by the lack of data on their cnidome composition. However, the comparison is made easier when the hydroid is known and well documented. 3. An attempt to rear the medusa proved unsuccessful, as a significant decay was observed after three days. 4. The cnidome composition was examined in fixed material upon measurements of ca. 30 capsules of each type. The sizes given in Table 1 correspond to undischarged capsules. Only a few discharged nematocysts were seen, and no reliable size range could be provided for them at this time. 5. The extremely rare occurrence of isorhizas in the gastrozooids did not allow their type to be determined with certainty. Their presence in the cnidome recalls Bouillonactinia carcinicola (Hiro, 1939). According to Namikawa (1997), up to 10 atrichous isorhizas could be found in each polyp of the Japanese hydroid. Spines on the shaft of the single discharged capsule observed in P. m art ini ca na were either absent or too inconspicuous to be noted, leading us to suspect that the nematocyst might be an atrichous isorhiza. However, the shape of undischarged capsules matches better the holotrichous isorhizas illustrated by Namikawa (1997) for the planula of B. carcinicola. The study of additional living material of the new species is expected to solve this issue. 6. Capsules with similar morphology were observed by Schuchert (2008) in the oral appendages of Podocoryna exigua (Haeckel, 1880), and were identified as microbasic euryteles. No discharged nematocyst of this type could be found in our material, and their precise identification is pending. 7. Three of these, originally placed in Hydractinia van Beneden, 1841, viz. H. guangxiensis Huang et al., 2010, H. moniliformis Huang et al., 2010, and H. spiralis Lin et al., 2010, are excluded from the following discussion, on account of several peculiar morphological features that contrast with the present concept of Podocoryna M. Sars, 1846, as well as on the absence of data on their hydroid stages. Thus, H. guangxiensis has the tentacle tips crowded with 14–28 large nematocysts of unreported type (Li et al. 2010). The second and third species have moniliform (Li et al. 2010) and spirally twisted (Lin et al. 2010) tentacles, respectively, thus differing from the strictly filiform condition displayed by all species of Podocoryna medusae described so far. In addition, the occurrence of all three nominal species in the Taiwan Strait, set them apart from P. martinicana. Unlike P. dubia (Mayer, 1900), P. ocellata (Agassiz & Mayer, 1902), P. uniformis (Stampar et al., 2006), and P. vacuolata (Xu & Huang, 2006), the medusae of P. martinicana are devoid of ocelli. When set free, they always bear four well developed marginal tentacles, in contrast to the following species, in which their number is increased: P. americana (Mayer, 1910), P. anechinata 8 Ritchie, 1907, P. areolata (Alder, 1862), P. australis Schuchert, 1996, P. b e l l a Hand, 1961, P. borealis (Mayer, 1900), P. carnea M. Sars, 1848, P. hayamaensis Hirohito, 1988, and P. tenuis (Browne, 1902) 9. In addition, a number of differences in their hydroid stage (when known) are listed in Table 2. Three species, namely P. a p i c a t a Kramp, 1959 b, P. dongshanensis (Xu & Huang, 2006), and P. exigua (Haeckel, 1880), possess medusae that are liberated and retain, during their whole life, only four tentacles 10. The former, whose hydroid stage is unknown, is characterized by the presence of a distinct gastric peduncle and of a mouth provided with four simple arms. No such structures were observed in our 3 -day old medusae of P. martinicana, though they may possibly develop subsequently. However, the remote geographical distribution of Kramp's species suggests that it is most probably distinct from ours. The hydroid of P. dongshanensis is equally unknown to allow establishing a comparison with that of P. martinicana, though the occurrence of its medusa in the Taiwan Strait, together with the presence of a black pigment in its tentacle bulbs, set it apart from the Caribbean species. Finally, the colonies of the European P. e x i g u a may occasionally form spines and spiral zooids (neither observed in our species), its gastrozooids are provided with only 10–13 tentacles, and the cnidome of the polyp includes desmonemes instead of isorhizas (Schuchert 2008). Podocoryna meteoris Thiel, 1938, described from a single medusa caught in Cape Verde, is provided with eight marginal tentacles, its manubrium buds off young medusae, and ends in twelve oral arms. No medusa budding was ever noted in the rather young medusae of P. martinicana, and the differences related to the marginal tentacles and the number and type of oral appendages may be diagnostic. 8. The tentacle number was not clearly stated by Ritchie (1907). On one hand, he explained that "During the earlier stages the tentacles appear as four blunt knobs, but these develop considerably ere the medusoid is set free". On the other hand, six tentacles are visible in his Pl. 23 Fig. 9. Rees & Thursfield (1965) hypothesized that Ritchie's material might belong to Podocoryna carnea M. Sars, 1848, though they were unable to demonstrate it unambiguously. 9. Several Chilean specimens described earlier by one of us (Galea 2007) were reexamined for this study. Their tentacle number varies between 4 and 8, and all bear medusa buds on their manubria. Although quite difficult to observe in fixed material, the more developed medusa buds appear provided with 5–8 tentacles. Consequently, we assume that the newly liberated medusae produced either sexually or asexually must bear 4–8 tentacles. 10. This situation is not excluded from occurring in P. martinicana, taking into account that its tentacles are already well developed at liberation, and no signs of additional, interradial marginal bulbs and tentacles are present. In addition, mainly due to geographical reasons, P. martinicana is most probably assumed to be different from P. polytentaculata (Xu & Huang, 2006), and P. recurvata (Lin et al., 2010) 11, both from the Taiwan Strait. Furthermore, the former species has the endoderm of the marginal bulbs crowded with a dark pigment, while the tentacle tips of the latter are reportedly swollen. Last but not least, the conspicuous bright pigmentation of the tentacles and hypostome of polyps, and that of the distal half of marginal tentacles of the medusa, together with the four white, interradial, manubrial spots, were never reported, to our knowledge, in any other hydractiniid described so far. Biology. Colonies of P. martinicana were exclusively found on gastropod shells inhabited by Iridopagurus caribbensis (A. Milne-Edwards & Bouvier, 1893). Examination of more than 100 shells gathered at 7 distinct stations (some up to 40 km distant), showed that about 5 % of them were not colonized by the hydroid, being very small (apertures less than 2.5 mm high) and inhabited by young crabs. Unlike other hydractiniid species, in which the colonies recover most of the host shell surface and have the various polyps scattered more or less homogenously throughout, the organizational pattern of both gastro- and gonozooids of P. martinicana is unique and invariant amongst specimens, regardless the origin of the shell inhabited by the hermit. Thus, a few gastrozooids are lined up along the inner lip of the shell. Their size is in accordance with their position along the lip: the centrally placed polyps are the tallest, while those placed laterally are gradually smaller (Pl. 1 F, G, Pl. 2 A). In contrast, all gonozooids exhibit a uniform height, and they dress a line nearly exclusively on the outer lip of the shell (Pl. 1 G, H, L, Fig. 1 B). Due to the numerous gonophores they carry, they are most often bent alternately forward and backward, thus optimizing the availability of space between them. In addition, it is likely that the specific occurrence of the gonozooids on the outer lip of the shell prevents potential damage of the fragile medusa buds when the crab burrows in sand (see also below and Pl. 1 A). New hydroid colonies develop first on the inner lips of recently acquired shells, regardless their shape and size. They are composed of a few gastrozooids, of which those placed more laterally may occasionally develop medusa buds (Pl. 2 A, Fig. 1 D). These fertile zooids are provided with fewer, almost normally developed tentacles (Pl. 2 B, C), and represent an intermediate stage between the truly feeding polyps and their generative counterparts. During the growth of the hydroid colony, the stolonal web progresses from a periderm-covered, more or less reticulate hydrorhiza, to a nearly fully coalescent plate investing the inner lip of the host shell (Pl. 1 F, Fig. 1 B). In only a few instances, the ectoderm at the base of polyps was observed to grow, to a varied extent, over the net of stolons, producing a sheet of naked coenosarc. Otherwise, the perisarc is practically never overlaid with coenosarc. On the other hand, the basal stolonal network extends towards the edge of the outer lip, forming a mat-like expansion beyond the shell aperture, the stolons there being mostly parallel and adnate. Consequently, the aperture of the shell may be increased, up to a couple of millimeters, providing a broader surface area to protect the hermit. As to the characteristic position of the gastrozooids in the closest vicinity of the buccal apparatus of the crab (Pl. 1 D, Fig. 1 A), preliminary observations suggest that it might potentially reflect a two-way relationship. On one hand, the crab lays pieces of food 12 on the polyp's hypostome, allowing it to take and ingest them. On the other hand, the crab gently "squeezes" the hydroid body, pushing it to regurgitate the digested food that, in turn, is ingested at once by the crab. It therefore appears that, at least in some circumstances, the hydroid serves as a food storage device for the hermit crab. In addition, there is evidence that the gastrozooids are possibly not capable of catching food by themselves. Indeed, hydroid colonies deprived of their pagurid host and cooped up in perforated jars, totally disappeared after three days in natural conditions. Compared to other congeners (see Table 2), the absence of desmonemes from the cnidome of gastrozooids of P. martinicana is striking. Indeed, these nematocysts were shown to play an important role in the adhesion to, and the entanglement of prey (Östman et al. 1991). In our case, their absence could be correlated with the nearly permanent contact between the gastrozooids and the hermit, thus possibly preventing their tentacles from adhering to the host. On the other hand, the numerous euryteles from the tentacles seem to not have any deleterious effect on the crab, in contrast with those species of hermits that avoid acquiring shells invested by hydroid colonies due to their apparent sensitiveness to the sting (Brooks & Mariscal 1985). Upon stressful situations for the crab (e.g. voluntary mechanical perturbation), it characteristically leaps up 11. Podocoryna is a feminine noun, and the original specific epithet recurvatus should be replaced by the correctly spelled recurvata. 12. Since the crabs exhibit very often a quarrelsome behavior, especially when several specimens occur together (as it usually happened during the sampling), pieces of chelipeds and legs are often procured from their defeated congeners, and offered to the hydroid. Large pieces of ingested food may be seen through the body of gastrozooids (Pl. 1 H), and are clearly revealed upon dissection of the polyps. backwards, making considerable jumps, up to 10 times its size. Upon a prolonged stress, it adopts two choices: it either draws into its shell, the gastrozooids forming a gate obstructing the shell aperture, or it buries in sand, leaving only its eyes, antennae, and the gonozooids protruding at surface. There is no actual evidence for an active role for the gastrozooids of P. martinicana in the defense of its host crab from potential predators. Within some symbioses, however, hydroids have been shown to either protect their host by deterring predators of hermits, or by deterring other crab species from using the same shells in order to minimize interspecific shell competition (summarized by Damiani 2003). Additional observations are therefore needed in order to document in a more comprehensive manner the nature of the symbiosis between P. martinicana and its host. Etymology. The specific name refers to Martinique, the Caribbean island from which the material described herein originates.Published as part of Galea, Horia R. & Ferry, Romain, 2013, Podocoryna martinicana, a new species of athecate hydroid (Cnidaria: Hydrozoa: Hydractiniidae) from the Caribbean, pp. 578-590 in Zootaxa 3710 (6) on pages 579-589, DOI: 10.11646/zootaxa.3710
Vilnius citizen Romain Gary
No full textReikšminiai žodžiai: II pasaulinis karas; Istorija; Prancūzija (France); Prancūzų autorius; Romain Gary; Romain Gary de Kacev; Romainas Gary; Romanas; Vilnius; France; French author; History; Lithuania; Novel; Romain Gary; Romain Gary de Kacev; Vilnius; World War IIThe mosi read French author in the whole world: 30 books in French, six books in English. Neither of these languages was his native tongue. Born in Vilnius on 8 May 1914, he recalled the city nostalgically, but after leaving it he never visited it again. He and his mother believed in his future fate, and it all came true: he became a famous writer, a French hero, and dressed as if he was in London. He wrote many of his books under pseudonyms, and often changed them. He created his work, and he also created himself. It often seemed to him that there was someone else inside him. Maybe it was always that dreamy boy from Pohulianka, ready to take any risk for the sake of beauty. He has no grave. The only monument to the writer Romain GARY is in Vilnius, his home town. Gary is presented to us by the translator Dalija Epšteinaitė
Electroencéphalographie et interfaces cerveau-machine : nouvelles méthodes pour étudier les états mentaux
No full textAvec les avancées technologiques dans le domaine de l'imagerie cérébrale fonctionnelle et les progrès théoriques dans la connaissance des différents éléments neurophysiologiques liés à la cognition, les deux dernières décennies ont vu l'apparition d'interfaces cerveau-machine (ICM) permettant à une personne d'observer en temps réel, ou avec un décalage qui se limite à quelques secondes, sa propre activité cérébrale. Le domaine clinique en général, et plus particulièrement celui de la neuropsychologie et des pathologies conduisant à un handicap moteur lourd, pour lesquels les applications potentielles sont nombreuses qu'elles soient thérapeutiques ou en vue d'une réhabilitation fonctionnelle, a constitué un moteur important de la recherche sur ce nouveau domaine des neurosciences temps réel. Parmi ces applications, le neurofeedback, ou neurothérapie, qui vise l'acquisition par le sujet du contrôle volontaire de certains aspects de son activité cérébrale en vue de les amplifier ou au contraire les diminuer dans un but thérapeutique, voire d'optimisation cognitive, représente une technique prometteuse, alternative aux thérapies et traitements médicamenteux. Cependant, la validation de ce type d'intervention et la compréhension des mécanismes mis en jeux en sont encore à leurs balbutiements. L'entraînement par neurofeedback est souvent long, pouvant s'étaler sur plusieurs semaines. Il est donc très probable que ce type de rééducation cérébrale sollicite des phénomènes de plasticité qui s'inscrivent dans une dynamique lente, et de ce fait, requiert une durée relativement longue d'entraînement pour atteindre les effets à long terme recherchés. Cependant, à cela peuvent s'ajouter de nombreux éléments perturbateurs qui pourraient être à l'origine de la difficulté de l'apprentissage et des longs entraînements nécessaires pour obtenir les résultats attendus. Parmi eux, les perturbations qui viennent déformer le signal enregistré, ou les éléments artefactuels qui ne font pas partie du signal d'intérêt, sont une première cause potentielle. Le manque de spécificité fonctionnelle du signal retourné au sujet pourrait en constituer une deuxième. Nous avons d'une part développé des outils méthodologiques de traitement du signal en vue d'améliorer la robustesse des analyses des signaux EEG, principalement utilisés jusqu'à maintenant dans le domaine du neurofeedback et des ICM, face aux artefacts et au bruit électromagnétique. D'autre part, si l'on s'intéresse au problème de la spécificité fonctionnelle du signal présenté au sujet, des études utilisant l'IRM fonctionnelle ou des techniques de reconstruction de sources à partir du signal EEG, qui fournissent des signaux ayant une meilleure spécificité spatiale, laissent entrevoir de possibles améliorations de la vitesse d'apprentissage. Afin d'augmenter la spécificité spatiale et la contingence fonctionnelle du feedback présenté au sujet, nous avons étudié la stabilité de la décomposition de l'EEG en différentes sources d'activité électrique cérébrale par Analyse en Composantes Indépendantes à travers différentes séances d'enregistrement effectuées sur un même sujet. Nous montrons que ces décompositions sont stables et pourraient permettre d'augmenter la spécificité fonctionnelle de l'entraînement au contrôle de l'activité cérébrale pour l'utilisation d'une ICM. Nous avons également travaillé à l'implémentation d'un outil logiciel permettant l'optimisation des protocoles expérimentaux basés sur le neurofeedback afin d'utiliser ces composantes indépendantes pour rejeter les artefacts en temps réel ou extraire l'activité cérébrale à entraîner. Ces outils sont utiles dans le cadre de l'analyse et de la caractérisation des signaux EEG enregistrés, ainsi que dans l'exploitation de leurs résultats dans le cadre d'un entraînement de neurofeedback. La deuxième partie de ce travail s'intéresse à la mise en place de protocoles de neurofeedback et à l'impact de l'apprentissage. Nous décrivons tout d'abord des résultats obtenus sur une étude pilote qui cherche à évaluer chez des sujets sains l'impact d'un protocole de neurofeedback basé sur le contrôle du rythme Mu. Les changements comportementaux ont été étudiés à l'aide d'un paradigme de signal stop qui permet d'indexer les capacités attentionnelles et d'inhibition de réponse motrice sur lesquelles on s'attend à ce que l'entraînement ICM ait une influence. Pour clore cette partie, nous présentons un nouvel outil interactif immersif pour l'entraînement cérébral, l'enseignement, l'art et le divertissement pouvant servir à évaluer l'impact de l'immersion sur l'apprentissage au cours d'un protocole de neurofeedback. Enfin, les perspectives de l'apport des méthodes et résultats présentés sont discutées dans le contexte du développement des ICMs de nouvelle génération qui prennent en compte la complexité de l'activité cérébrale. Nous présentons les dernières avancées dans l'étude de certains aspects des corrélats neuronaux liés à deux états mentaux ou classes d'états mentaux que l'on pourrait qualifier d'antagonistes par rapport au contrôle de l'attention : la méditation et la dérive attentionnelle, en vue de leur intégration à plus long terme dans un entraînement ICM par neurofeedback.With new technological advances in functional brain imaging and theoretical progress in the knowledge of the different neurophysiologic processes linked to cognition, the last two decades have seen the emergence of Brain-Machine Interfaces (BCIs) allowing a person to observe in real-time, or with a few seconds delay, his own cerebral activity. Clinical domain in general, and more particularly neuropsychology and pathologies leading to heavy motor handicaps, for which potential applications are numerous, whether therapeutic or for functional rehabilitation, has been a major driver of research on this new field of real-time neurosciences. Among these applications, neurofeedback, or neurotherapy, which aims the subject to voluntary control some aspects of his own cerebral activity in order to amplify or reduce them in a therapeutic goal, or for cognitive optimization, represents a promising technique, and an alternative to drug treatments. However, validation of this type of intervention and understanding of involved mechanisms are still in their infancy. Neurofeedback training is often long, up to several weeks. It is therefore very likely that this type of rehabilitation is seeking brain plasticity phenomena that are part of slow dynamics, and thus require a relatively long drive to achieve the desired long-term effects. However, other disturbing elements that could add up to the cause of the difficulty of learning and long training sessions required to achieve the expected results. Among them, the disturbances that come from recorded signal distortions, or artifactual elements that are not part of the signal of interest, are a first potential cause. The lack of functional specificity of the signal returned to the subject could be a second one. We have developed signal processing methodological tools to improve the robustness to artifacts and electromagnetic noise of EEG signals analysis, the main brain imaging technique used so far in the field of neurofeedback and BCIs. On the other hand, if one looks at the issue of functional specificity of the signal presented to the subject, studies using functional MRI or source reconstruction methods from the EEG signal, which both provide signals having a better spatial specificity, suggest improvements to the speed of learning. Seeing Independent Component Analysis as a potential tool to increase the spatial specificity and functional contingency of the feedback signal presented to the subject, we studied the stability of Independent Component Analysis decomposition of the EEG across different recording sessions conducted on the same subjects. We show that these decompositions are stable and could help to increase the functional specificity of BCI training. We also worked on the implementation of a software tool that allows the optimization of experimental protocols based on neurofeedback to use these independent components to reject artifacts or to extract brain activity in real-time. These tools are useful in the analysis and characterization of EEG signals recorded, and in the exploitation of their results as part of a neurofeedback training. The second part focuses on the development of neurofeedback protocols and the impact of learning. We first describe the results of a pilot study which seeks to evaluate the impact of a neurofeedback protocol based on the Mu rhythm control on healthy subjects. The behavioral changes were studied using a stop signal paradigm that indexes the attentional abilities and inhibition of motor responses on which the BCI training can possibly have influence. To conclude this section, we present a new tool for immersive interactive brain training, education, art and entertainment that can be used to assess the impact of immersion on learning during a neurofeedback protocol. Finally, prospects for methods and results presented are discussed in the context of next-generation BCI development which could take brain activity complexity into account. We present the latest advances in the study of certain aspects of the neural correlates associated with two mental states or classes of mental states that could be described as antagonistic with respect to the control of attention: meditation and mind wandering, for their integration in the longer term in an BCI training using neurofeedback
Grands Albums Hachette
No full textSee my earlier version of this book, listed under 1953/66. I ordered this one through eBay because it was listed as published in 1953. I will keep trying for a first edition. Whereas that book was printed in France, this was printed in Italy. Let me repeat my remarks from there: My, Romain Simon illustrated many different books! This is a 28-page oversized (9 x 12½) children's book. There are eleven fables in all, each allotted one to three pages. At least five of them are included somehow in the endpieces at both ends of the book. The stories include GA, FC, FG, LM, TMCM, TH, MM, The Fox and the Goat, WL, FS, and TT. Has the lively, skipping rabbit appeared in Simon's work before? The scarf and shawl on the tortoise make me think I have seen these characters before!This is a hardbound book (hard cover)Language note: FrenchText nach einem Film von Georges de la Grandière; Nacherzählt nach der Fabel von La Fontain
Nemalecium gracile Galea, Ferry & Bertot, 2012, sp. nov.
No full textNemalecium gracile sp. nov. (Figs 2 H–N, 3, 4 A–D; Table 1) Nemalecium lighti — Calder, 1991 a: 27, figs 17, 18.— Galea, 2008 (pro parte): 24, fig. 4 M, O [not fig. 4 N = Nemalecium cf. lighti (Hargitt, 1924)]. not Halecium lighti Hargitt, 1924, 489, pl. 4 fig. 13. Material examined. Nemalecium gracile — Martinique, Les Abîmes, lat. 14.807514, long. -61.226698, 25 February 2012, 8 m, sample M 257: female colony, ca. 3.5 cm high, with ripe gonophores (holotype, MHNG- INVE- 82194); sample M 258: male colony, ca. 3.0 cm high, with ripe gonophores (paratype, MHNG-INVE- 82195). Martinique, Anse Trois Airs, lat. 14.513223, long. -61.097730, 0 4 February 2012, sample M 147: colony up to 2.4 cm high, with mono- and dioecious stems, on Pinna carnea (Bivalvia) (MHNG-INVE- 82196). Martinique, Pointe Lamare, lat. 14.780461, long. -61.211935, 28 January 2012, 10 m, sample M098: monoecious colony on Halimeda sp. Martinique, Petite Sirène, lat. 14.490951, long. -61.089147, 29 January 2012, 6 m, sample M 114: female colony, ca. 1.2 cm high, on Halimeda sp. Guadeloupe, Stn1. 1, 20 March 2008, several colonies, ca. 5 mm high, some fertile, on Thalassia testudinum. Guadeloupe, Stn. 6, 28 March 2008, numerous colonies, some fertile, up to 0.4 cm high, on T. testudinum. Guadeloupe, Stn. 7, 27 March 2008, a few sterile colony, up to 0.5 cm high, on T. testudinum. Nemalecium cf. lighti (Caribbean) — Guadeloupe, Stn. 6, 23 March 2008: numerous sterile colonies, with both mono- and polysiphonic stems, up to 5.0 cm high, on various algae, concretions and sponge. Guadeloupe, Stn. 7, 25 March 2008: a monoecious colony, ca. 1.8 cm high, on sponge; 27 March 2008, a 1. Data on stations from Guadeloupe are given in Galea (2008). few sterile colonies, up to 1.0 cm high, on hydrocoral. Martinique, Les Abîmes, sample M 252: colonies on dead gorgonians, up to 2.0 cm high, some stems bearing rare, immature male gonothecae. Nemalecium cf. lighti (Indonesia) —Hatta (Rozengain) Island, lat. -4.590954, long. 130.039919, 19 October 2011, 7 m: portion of a rich colony growing on hydrocoral, with stems up to 1.2 cm high and numerous mature male gonothecae. Derawan Island, lat. 2.284377, long. 118.243072, 18 April 2010, 15 m: portion of a colony growing on dead gorgonian, stems up to 1.8 cm high, some bearing immature male gonothecae. Alor Island, lat -8.272613, long. 124.400860, 29 October 2010, 20 m: small colony composed of a few stems detached from substrate, up to 2.2 cm high, some bearing mature male gonothecae. Description. Delicate, upright, unbranched or sparingly branched, coplanar colonies, up to 3.5 cm high, with mono- or slightly polysiphonic stems, arising at irregular intervals from creeping, ramified hydrorhiza (Figs 2 H, 3 A). Stems and side branches divided into internodes by transverse to slightly oblique nodes; internodes long, slender, slightly geniculate, of approximately the same length (Fig. 2 I); distally with a lateral hydrophore and an upwards-directed apophysis supporting subsequent internode. Hydrophore slightly surpassing level of distal node, bearing a hydrotheca at top (Fig. 2 J). Side branches borne on short apophyses given off laterally from hydrophores, just below hydrothecal bases (Fig. 2 I 1); first internode comparatively longer than subsequent ones; branching up to 3 rd order. Hydrotheca shallow, walls straight, slightly flaring, margin not everted, rather slightly rolled inwardly for a short distance; distinct, large desmocytes as a ring of refringent nodules above diaphragm (Fig. 2 J). Renovated hydrothecae occur irregularly; secondary hydrothecae arising at level of diaphragm from within primary hydrothecae; borne on funnel shaped hydrophores of varied length, perisarc annulated basally, smooth elsewhere (Fig. 2 I 3–5). Hydranths tall, slender, constantly foraging; distally, a prominent constriction, delimiting the hypostome region from the rest of the body; body with a short, distal, slightly swollen digestive region, bright yellow in life, and a much longer, non digestive part below, nearly transparent in life (Fig. 3 A, insert); hypostome region conical, bearing terminally the mouth, encircled by a row of 22–26 filiform tentacles (Fig. 3 B), characteristically irregularly raised (Fig. 3 A, insert); normally two conspicuous nematodactyls; between tentacle bases, large glandular cells (Fig. 3 E), these also scattered over the hydranth body as ovoid, granular patches (Fig. 3 B, g.c.); nematodactyls curved inwards towards hypostome from diametrically opposite sides or nearly so; each armed along either side with a row of 12–13 large pseudostenoteles (Fig. 3 F). Nematocysts (Fig. 4 A–D): 1) pseudostenoteles, 2) microbasic mastigophores typical of the haleciid hydroids, 3) microbasic euryteles resembling the microbasic mastigophores, but comparatively wider, and 4) ovoid rhopaloid heteronemes with oblique shaft (for measurements, see Table 1). Colonies and individual stems either mono- or dioecious. Gonothecae given off from primary hydrophores below hydrothecal bases (Fig. 2 K, L, N, 3 H–J), occasionally from the stolon. Gonothecae of both sexes similar, tubular, tapering gradually basally, walls undulated, distally truncate to watch glass shaped. Gonophores one per gonotheca, budded off from a blastostyle ending in a conspicuous apical plate, all enveloped together in an ectodermic mantle (Fig. 3 J). Gonophores of cryptomedusoid type; large, ovoid, with thick mesoglea; an eccentric, moderately long, club shaped spadix (Fig. 3 P) surrounded by a compact mass of gametes, living only a reduced subumbrellar cavity (Fig. 3 J); basally a fairly developed velum; bell aperture surrounded by a belt of spherical (8.5–17.0 µm wide), solid, refringent corpuscles arranged in 1–3 concentric rows (Fig. 3 L and insert); subumbrella provided with conspicuous transverse myoepithelial cells (Fig. 3 O); there are no radial or circular canals, no tentacles, no mouth, and no sense organs. Female gonophore with ca. 30–35 polygonal eggs with large nuclei (Fig. 3 H). Elongating blastostyle, followed by the mantle withdrawal allow the gonophore to be progressively liberated (Fig. 3 K) through the rupture of a rounded, apical "lid" of the gonotheca (fig. 2 M). Spawning and fertilization could not be observed in either sex. Discussion. The material assigned to Nemalecium lighti (Hargitt, 1924) by Calder (1991 a) shows striking resemblances to the present species. The shape and size of the internodes, the primary hydrophores surpassing the level of the distal node, as well as the size of the pseudostenoteles, strongly suggest that it is conspecific with N. gracile (see also Table 1 for comparison). The same is partly true for the material studied earlier by Galea (2008). Indeed, upon its reexamination, it was found that it is actually composed of two species, one of which is N. gracile. Distinction between them is easier, especially when living specimens are examined, given the present material from Martinique. Nemalecium gracile has very long, nearly transparent (except for the digestive part, with a conspicuous bright yellow tinge), constantly foraging hydranths, whose tentacles are typically raised at different levels (see insert of Fig. 3 A). In contrast, the second species 2 has shorter, nearly immobile, milky white hydranths (except for their digestive part, which is pale yellow), with all tentacles always raised at the same level. Microscopically, both species are especially distinguished through the shape and size of their internodes (compare Fig. 2 I 1–5 and 2 P, Q), as well as the cnidome composition (compare Fig. 4 A–D and E–H). The type material of N. lighti, the sole nominal species belonging so far to that genus, was not examined and specimens from the type locality (Puerto Galera, Mindoro Oriental, Philippines) were unavailable for this study in order to confirm the identification of the second Caribbean species. However, material belonging to Nemalecium originating from three remote (700–1500 km distant) Indonesian localities (Alor, Derawan, and Hatta islands) is housed in the private collection of the senior author and was therefore available for comparison with the original description of N. lighti by Hargitt (1924) and with the Caribbean specimens in hand. The materials from Alor and Derawan agree well with the description of the type of N. lighti (especially in the colony structure and the length of their internodes 3), and they are most probably conspecific. In contrast, the colony from Hatta, growing over a gorgonian, has a different appearance and seems to display a few distinctive features, such as a tendency to form widely-spaced, mostly unbranched, rather stout stems, with irregular internodes (Fig. 2 X), while the specimens from Alor and Derawan form characteristically more crowded stems, branched strictly in one plane, and provided with typical collinear internodes (Fig. 2 U, V). In contrast, the cnidome seems uniform in all three sets of material 4. 2. A living colony from Guadeloupe is illustrated in Galea (2010), p. 6, fig. 1 A. 3. Material with a similar trophosome was reported on by Pennycuik (1959) from Queensland, Australia. 4. This should be checked again using living material so as to obtain fully discharged capsules. data and the present study. N.I. signifies that information was not indicated by the authors cited. N.B.: Male and female gonothecae of the Caribbean specimens assigned to Nemalecium cf. lighti were not fully formed and their dimension are expected to be above the range given herein. There is increasing evidence that we are most probably dealing with more than one species of Nemalecium in the Indo-Pacific, some materials having been likely erroneously assigned earlier to the binomen N. lighti, as exemplified by the specimens from Papua New Guinea studied by Bouillon (1986). His material displays some obvious morphological differences compared to the type of N. lighti described by Hargitt (1924), such as the presence of very long, slender internodes, similar to those of N. gracile. In addition, Di Camillo et al. (2008) mentioned an as yet unnamed species inhabiting the "shady crevices of the corals" in North Sulawesi, while Gravier-Bonnet & Bourmaud (2006) found another species "colonizing walls and tips of large grey sponges" in Juan de Nova Island, as well as two additional species occurring in the Maldives (Gravier-Bonnet & Bourmaud 2012) 5. We conclude that a comprehensive study of Nemalecium, based on abundant, fertile material, is imperative, though out of the scope of the present paper. Subtle morphological differences could, indeed, be noted only if living material is studied, including the precise identification of the nematocyst types upon obtaining fully discharged capsules. On the other hand, comparison of the second species of Nemalecium from the Caribbean (Fig. 2 P, Q) with the materials from Alor and Derawan indicate that they are indistinguishable morphologically from each other, a conclusion equally supported by their respective cnidomes (compare Fig. 4 E–H and 4 I –L). Therefore, we tentatively assign the second Caribbean Nemalecium to Hargitt's (1924) species, pending reexamination of the type of N. lighti. It is curious to note that the cnidome of Nemalecium was underestimated in earlier accounts (Bouillon 1986, Calder 1991 a, Migotto 1996). In addition to the conspicuous pseudostenoteles and the numerous microbasic mastigophores, it appears to comprise at least two additional, less abundant types of capsules: a microbasic eurytele similar in length to the mastigophores, but comparatively wider (Fig. 4 C, G, K), and an unidentified rhopaloid heteroneme, possibly a microbasic eurytele (Fig. 4 D, H, L). Pseudostenoteles are found not only in the nematodactyls (Fig. 3 F, G), but occur also in the coenosarc of the trophosome, as well as in the gonophores, where they are more easily seen in the male medusoids as large capsules (p.s.) scattered among the mass of sperm cells (Fig. 3 P). The microbasic mastigophores (m.b.m.) heavily arm the filiform tentacles of the hydranths (Fig. 3 F), but are equally found in the coenosarc and the exumbrella of the medusoid. The microbasic euryteles occur in the coenosarc of the trophosome, as well as in the gonophore mantle, while the heteronemes are found in the coenosarc and the spadix of the medusoid. Based on the cnidome composition alone, especially on the shape and size of the pseudostenoteles, it is obvious that N. gracile could be readily distinguished, through its comparatively smaller capsules (Calder 1991 and the present study), from the Indonesian (present study), Papua New Guinean (Bouillon et al. 1986), and Brazilian (Migotto 1996) materials, as well as from the Caribbean specimens provisionally assigned to N. lighti. The swimming gonophores of N. gracile are morphologically similar to, and exhibit apparently the same expulsion mechanism from the gonotheca as those described earlier by Gravier-Bonnet & Migotto (2000) for N. cf. lighti 6. Gross differences rely in the number of eggs (possibly 7 30–35 vs. 40–62) and the shape of the marginal corpuscles (rounded vs. irregular). Similarities between the medusoids of Nemalecium and those belonging to other hydrozoan families have been discussed at length by the above-mentioned authors. Due to their apparent mineral composition and their shape and size possibly being influenced by physicochemical parameters, it is unclear whether these corpuscles are good indicators for the separation of species. Morphological differences have been observed, for instance, between specimens from Reunion and Brazil, as noted by Gravier-Bonnet & Migotto (2000). Moreover, corpuscles with heterogenous morphology may occur within the same species, as illustrated by Antennella sp. from Reunion Island (Bourmaud & Gravier-Bonnet 2005). On the other hand, the number of eggs should be, in theory, species-specific, but there are contrary evidences demonstrating that it can vary depending on environmental factors in at least two documented cases: Macrorhynchia philippina and an as yet unidentified Rhizogeton from the Indian Ocean (Bourmaud & Gravier- Bonnet 2004). 5. Due to complete absence of formal descriptions and illustrations, all these "species" records are considered with some reservation, and are listed herein for information only, pending detailed taxonomical studies that clarify their identities. 6. According to Gravier-Bonnet & Migotto (2000), slight differences were observed between the specimens from São Sebastião and those from Reunion Island, suggesting that they were probably dealing with two different species. 7. Egg number could not be evaluated with certainty in non-spawned medusoids. Their number was estimated in nonreleased gonophores, through the transparency of the gonothecal wall. Attempts to estimate their number in dissected, formalin-fixed gonophores proved inconclusive. Since neither swimming of the gonophore, nor the spawning could be observed in N. gracile, it is assumed that the role of the subumbrellar myoepithelial cells is to favor peristaltic movements of the bell allowing the gametes to be liberated out of the gonophore, while the contractions of the velum would help the medusoid to swim and spread its gametes in the water column. Ecology. Nemalecium gracile occurs on Halimeda sp., on the leaves of Thalassia testudinum, on some bivalve shells (e.g. Pinna carnea), and on artificial inert substrates (e.g. fishing wires). In contrast, N. cf. lighti of the tropical western Atlantic is found on a larger variety of substrates, mainly sponges and (dead) gorgonians, but also on mineral concretions, worm tubes, various artificial inert substrates, or the algae Tricleocarpa sp. and Amphiroa sp., as well as Halimeda sp. Geographical distribution. Bermuda (Calder 1991 a), Guadeloupe (Galea 2008, pro parte), Martinique (present study), possibly Belize (Calder 1991 b, as N. lighti, presumably the specimens growing on T. testudinum). The species is expected to occur in the whole Caribbean basin and northwards to Bermuda, and possibly to the neighboring Gulf of Mexico (though not listed by Calder & Cairns 2009). Etymology. The specific name gracile, Latin, meaning “slender” or “thin”, makes reference to the delicate appearance of the colonies and the features of their internodes.Published as part of Galea, Horia R., Ferry, Romain & Bertot, Jean-Marie, 2012, Medusoids in the life cycle of Dentitheca dendritica (Nutting, 1900) and Nemalecium gracile sp. nov. (Cnidaria: Hydrozoa), pp. 43-54 in Zootaxa 3527 on pages 47-53, DOI: 10.5281/zenodo.28275
What is European integration really about? A political guide for economists
No full textEurope’s monetary union is part of a broader process of integration that started in the aftermath
of World War II. In this “political guide for economists” we look at the creation of the euro
within the bigger picture of European integration. How and why were European institutions
established? What are the goals and determinants of European Integration? What is European
integration really about? We address these questions from a political-economy perspective,
building on ideas and results from the economic literature on the formation of states and
political unions. Specifically, we look at the motivations, assumptions, and limitations of the
European strategy, initiated by Jean Monnet and his collaborators, of partially integrating
policy functions in a few areas, with the expectation that more integration will follow in other
areas, in a sort of chain reaction towards an “ever-closer union.” The euro with its current
problems is a child of that strategy and its limits
Linguistic Innovations In Romain Gary\u27s Creative Laboratory
No full textIn this article we study a new background revealed due to Russian translations made by N.Mavlevich in 2015 of the first unpublished novel by Romain Gary, holder of the two Prix Goncourt prizes for his novels The Roots of Heaven (Les Racines du ciel) and The Life Before Us (La vie devant soi) published under the pseudonym Emile Ajar. The empirical writer mentioned about his debut novel in the book The Night is Calm (La nuit sera calme) and his posthumous literary essay The Life and Death of Emil Ajar (Vie et mort d\u27Emile Ajar) thus giving a clue to understanding of his “creative laboratory” related to phenomenal literary mystification. We assume that language experts will be interested in studying of Romain Gary\u27s linguistic biography who created his novels in English and French, considering the fact that Russia was the country where his linguistic development had started. By understanding the role and place of the author\u27s creative laboratory in linguistics we can define relevance and academic novelty of suggested study. The study allows to analyse Romain Gary\u27s creative works from a new perspective and goes beyond the existing method of obtaining knowledge. The main research objects include the author\u27s language and linguistic behaviour of his characters that are featured with well-structured images evoked by Russian words kept in mind from childhood. This system of values is close to the Russian readers and is in tune with the spirit of the modern age. This aspect in the framework of the language-specific nature can be a subject for further research. Linguistic findings made by Romain Gary facilitated the development of the literary language and were focused on increasing of capabilities of the literary speech. Analysis of linguistic innovations in the Romain Gary\u27s creative laboratory allows to receive important information about peculiarities of links between the cognitive and linguistic content discovered in linguistic facts and speech phenomena and make some crucial observations
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