1,622 research outputs found
Trefusialaimus idrisi Leduc 2013, sp. nov.
No full text<i>Trefusialaimus idrisi</i> sp. nov. <p>Figs 3-4; Table 1</p> <p>urn:lsid:zoobank.org:act: 56BD1B40-542A-4FE2-BB84-F8FC7C5C2667</p> Diagnosis and relationships <p> <i>Trefusialaimus idrisi</i> sp. nov. is characterised by relatively short body length, presence of numerous golden inclusions in the chords, cephalic setae 0.65-0.80 cbd long, spicules 2.3 abd long, 4 pairs of pericloacal papillae, and long, gradually tapering tail.</p> <p> Until now, only two <i>Trefusialaimus</i> had been described, viz., <i>T. magnus</i> (Filipjev, 1946) and <i>T. monorchis</i> Riemann, 1974. <i>Trefusialaimus idrisi</i> sp. nov. is similar to <i>T. magnus</i> in the shape of the copulatory apparatus and tail, but can be differentiated from the latter by the shorter body length (4540 <i>vs.</i> 7700 <b>M</b> m), lower value of c (7 <i>vs.</i> 21), longer cephalic setae (0.65-0.80 <i>vs.</i> 0.4 cbd), longer spicules (2.3 <i>vs.</i> 1.7 abd), and longer tail (38 <i>vs.</i> 11 abd). <i>T. idrisi</i> sp. nov. can easily be differentiated from <i>T. monorchis</i> by the markedly longer cephalic setae (0.65-0.80 <i>vs.</i> 0.26 cbd), absence of pre- and post-cloacal papillae (present in <i>T. monorchis</i>), and tail shape (gradually tapering <i>vs.</i> conico-cylindrical).</p> Etymology <p>The species is named after Idris Matai Kljucanin Brun, the author’s godson.</p> Material examined <p> <b>Holotype</b></p> <p>♂, collected on 20 Feb. 2011 (NIWA cruise TAN1103, station 69), central Chatham Rise (43.331° S, 178.288° E), water depth 350 m, sediment depth 1-5 cm, mean grain size 55-59 µm, %sand 55-57%, particle sorting (geometric) 4.1-4.3 (NIWA 88349).</p> <p> <b>Paratype</b></p> <p>1 juvenile, same data as holotype (NIWA 88350).</p> Description <p> <b>Male</b></p> <p> Body cylindrical, slender, tapering slightly towards anterior extremity (Fig. 4D), with slight golden colouration due to the presence of numerous round, <i>ca.</i> 1 µm diameter, golden inclusions in the chords (i.e., longitudinal thickenings of the hypodermis protruding internally between the sectors of the longitudinal muscles; Chitwood & Chitwood 1974) (Fig. 4E). Cuticle smooth, thin, <i>ca.</i> 0.7-0.9 µm thick, except in head region (anterior to cephalic setae) where it is slightly thicker, 1.0- 1.6 µm. Head rounded, slightly set-off from body due to thickened cuticle, with three lips, each bearing two small, conical inner labial papillae 1.0- 1.5 µm long (Fig. 3B). Six outer labial setae and four cephalic setae in one circle, double-jointed; cephalic setae slightly longer than outer labial setae (0.75-0.80 cbd <i>vs.</i> 0.65 cbd). Sub-cephalic and somatic setae absent. Amphid pocket-shaped with oval aperture, <i>ca.</i> 6 µm wide by 2 µm high (Fig. 3A). Buccal cavity funnel-shaped, without teeth. Pharynx cylindrical, slightly swollen at posterior extremity, completely surrounds buccal cavity. Pharyngeal lumen lightly but distinctly cuticularised at anterior extremity (Figs 3B, 4B). Nerve ring situated at <i>ca.</i> 50% of pharynx length. Secretory-excretory system not observed. Cardia small.</p> <p> Reproductive system monorchic with single outstretched testis, <i>ca.</i> 1960 µm long. Position of testis relative to intestine difficult to ascertain. Elongated sperm cells, ca 3-5 µm wide by 13-16 µm long, with central rod and nucleus at one extremity (Fig. 3G); vas deferens <i>ca.</i> 520 µm long, without muscular ejaculatory duct. Paired, equal spicules, 2.3 abd long, slightly bent near distal one third, with broad proximal end and narrow pointed distal end; velum present (Fig. 3D). Gubernaculum with two pairs of narrow, pointed lateral crurae (Fig. 3E). Four pairs of small, conical peri-cloacal papillae (Fig. 3F). Precloacal supplements absent. Tail long, <i>ca.</i> 14% of total body length, narrow, gradually tapering, without setae (Fig. 3H).</p> <p> <b>Juvenile</b></p> <p> Similar to male, but with shorter and narrower body, shorter cephalic setae (Figs 3C, 4B), and smaller amphid. Numerous sperm cells are present throughout the pseudocoelom from <i>ca.</i> 90 µm posterior to pharynx to <i>ca.</i> 200 µm anterior to anus (Fig. 4C). Genital and copulatory (i.e., cloacal or vulval) primordia not observed.</p> Discussion <p> The presence of sperm cells in the pseudocoelom of the juvenile <i>Trefusialaimus idrisi</i> sp. nov. specimen is unusual. Some nematode species, such as <i>Oncholaimus oxyuris</i>, can transfer sperm through traumatic insemination (Coomans <i>et al</i>. 1988), a process whereby the male injects sperm directly into the body of a female (or potentially even a male or juvenile) by piercing the cuticle with the spicules. The presence of sperm cells in the juvenile specimen could be explained if a similar process occured in <i>T. idrisi</i> sp. nov. The existence of such a reproductive strategy, however, is highly conjectural because no <i>Trefusialaimus</i> females have ever been observed and (to my knowledge) traumatic insemination has not been described in the suborder Trefusiina.</p> <p> <i>Trefusialaimus idrisi</i> sp. nov. was rare at the study site, with only four specimens (the two type specimens and two juveniles in poor condition, each from a different subcore) recorded out of the 4412 individuals that were identified by Leduc & Pilditch (2013). All individuals were found in the surface (0-1 cm) sediment layer (D. Leduc, unpublished data). A single juvenile specimen (out of 4550 specimens identified from 30 locations on the New Zealand continental margin) was recorded from a site on the northern flank of Chatham Rise at a depth of 1000 m (178.500° E, 44.333° S; silt/clay content 95%) (Leduc <i>et al</i>. 2012a; D. Leduc unpublished data).</p>Published as part of <i>Leduc, Daniel, 2013, Two new free-living nematode species (Trefusiina: Trefusiidae) from the Chatham Rise crest, Southwest Pacific Ocean, pp. 1-13 in European Journal of Taxonomy 55</i> on pages 8-12, DOI: 10.5852/ejt.2013.55, <a href="http://zenodo.org/record/3822945">http://zenodo.org/record/3822945</a>
Jean Weiller. Problèmes d'économie internationale, t. II : Une nouvelle expérience : l'organisation internationale des échanges
No full textLeduc Gaston. Jean Weiller. Problèmes d'économie internationale, t. II : Une nouvelle expérience : l'organisation internationale des échanges. In: Politique étrangère, n°4-5 - 1951 - 16ᵉannée. pp. 424-426
Jean Weiller. Problèmes d'économie internationale, t. II : Une nouvelle expérience : l'organisation internationale des échanges
No full textLeduc Gaston. Jean Weiller. Problèmes d'économie internationale, t. II : Une nouvelle expérience : l'organisation internationale des échanges. In: Politique étrangère, n°4-5 - 1951 - 16ᵉannée. pp. 424-426
Trefusia piperata Leduc 2013, sp. nov.
No full textTrefusia piperata sp. nov. Figs 1-2, Table 1 urn:lsid:zoobank.org:act: 43C390C6-9807-4050-857F-02E4538D9920 Diagnosis and relationships Trefusia piperata sp. nov. is characterised by six double-jointed outer labial setae with conspicuous clusters of dark granules at their base, four cephalic setae at level of amphid, one seta posterior to each amphid, and long filiform tail. Male is characterised by six cervical papillae, eight papillose pre-cloacal supplements, slightly bent spicules, and gubernaculum with funnel-shaped distal portion and pointed projections. Trefusia piperata sp. nov. most closely resembles T. helgolandica Riemann, 1966, described from subtidal sediments in the German Bight. The two species are similar in the shape and position of the outer labial setae and cephalic setae, as well as in the structure of the spicules and gubernaculum. The new species, however, differs from T. helgolandica in head diameter (14-15 vs. 22-25), maximum body width (21-22 vs. ≥ 33), spicule length (24 vs. 38), number of setae posterior to the amphids (one vs. two or three), the number and shape of cervical papillae (six papillae with wide base vs. thirteen papillae without wide base), and number of pre-cloacal supplements (eight vs. fourteen). Trefusia piperata sp. nov. also differs from T. helgolandica in the presence of conspicuous clusters of dark granules at the base of the outer labial setae. Etymology The species name is derived from the latin word piperatus (= peppered), and refers to the conspicuous clusters of dark granules at the base of the cephalic setae. Material examined Holotype ♂, collected on 20 Feb. 2011 (NIWA cruise TAN1103, station 69), central Chatham Rise (43.331° S, 178.288° E), water depth 350 m, sediment depth 1-5 cm, mean grain size 55-59 µm, %sand 55-57%, particle sorting (geometric) 4.1-4.3 (NIWA 88347). Paratype 1 ♀, same data as holotype (NIWA 88348). Description Male Body cylindrical, slender, tapering slightly towards anterior extremity (Fig. 2C). Cuticle thin, <1 µm thick, with very fine striations, difficult to observe. Head blunt, slightly rounded, with three lips; six small conical inner labial sensillae, ~ 1 µm long, six double-jointed outer labial setae with blunt ends, ca. 0.7 cbd (Fig. 1B). Conspicuous clusters of dark brown granules situated at base of each outer labial seta (Fig. 2A). Four cephalic setae at level of amphid, jointed, 5-7 µm long (Fig. 1B). Amphid pocket-shaped with oval aperture, ca. 4 µm wide by 2 µm high. One seta situated ca. 25 µm posterior to each amphid, 5 µm long. No other somatic setae observed. Six small cervical papillae with wide base situated ventrally in longitudinal row; row extends from posterior of amphid to about 60% of pharynx length from anterior (Fig. 1B). Buccal cavity funnel-shaped, without teeth. Pharynx cylindrical, slightly swollen at anterior and posterior extremities, completely surrounds buccal cavity. Nerve ring situated at ca. 45% of pharynx length from anterior extremity. Secretory-excretory system not observed. Cardia very small. *at level of cephalic setae Reproductive system diorchic with outstretched testes. Position of testes relative to intestine difficult to ascertain. Sperm cells drop-shaped with rod-shaped nucleus; vas deferens ca. 445 µm long. Paired, equal spicules, slightly bent near distal one third, without obvious central cuticularised projection (i.e., lamella or median rib). Gubernaculum with narrow proximal region and funnel-shaped distal region with large anterior pointed projection and smaller posterior pointed projection (Figs 1D, 2B). Eight small papillose pre-cloacal supplements situated ventrally, 6-15 µm apart except for anterior-most supplement which is situated 40 µm from next supplement. Tail very long, ca. half of total body length, filiform, without setae, tightly coiled. Female Similar to male, but with slightly shorter cephalic setae and slightly smaller amphid (Fig. 1A). Female reproductive system didelphic, amphidelphic with reflexed ovaries. Position of ovaries relative to the intestine difficult to ascertain. Vulva situated at one third of body length (Fig. 1C). Discussion Trefusia piperata sp. nov. was rare at the study site, with only four specimens (the two type specimens and two juveniles in poor condition, each from a different subcore) recorded out of the 4412 individuals that were identified by Leduc & Pilditch (2013). Two individuals were found in the 1-3 cm sediment depth layers, and two were found in the 3-5 cm sediment depth layer (D. Leduc, unpublished data).Published as part of Leduc, Daniel, 2013, Two new free-living nematode species (Trefusiina: Trefusiidae) from the Chatham Rise crest, Southwest Pacific Ocean, pp. 1-13 in European Journal of Taxonomy 55 on pages 3-7, DOI: 10.5852/ejt.2013.55, http://zenodo.org/record/382294
Integration of urban knowledge through visibility studies and pedestrian behavior analysis in Old Bazaar in Skopje
No full textThelonema clarki Leduc 2015, sp. nov.
No full textThelonema clarki sp. nov. urn:lsid:zoobank.org:act: F 4ED998A-656F-48D1-8FBC-B0031 BA 943D9 Figs 1–3, Table 1 Diagnosis Thelonema clarki sp. nov. is characterised by large adult body size (3230–4461 μm), short cylindrical buccal cavity with cuticularised walls, sub-cephalic setae of similar length or shorter than outer labial setae, secretory-excretory system with two or three renette cells, gubernaculum without apophyses, and conico-cylindrical tail 6.4–10.4 abd long. Etymology This species is named after Malcolm R. Clark, principal investigator of the HADES project (HADal Ecosystem Studies) who has made an outstanding contribution to the field of deep-sea ecology and who kindly supported the involvement of the author on the Kermadec Trench voyage. Material examined Holotype KERMADEC TRENCH: ♂ (NIWA 99760), collected 6 May 2014 (WHOI cruise TN309, Nereus dive N074). Paratypes KERMADEC TRENCH: 2 ♀♀ (NIWA 99761) and 1 juvenile (NIWA 99762), collected 7 May 2014 (WHOI cruise TN309, Nereus dive N075). Type habitat KERMADEC TRENCH: water depth: 8081 m (178.17571º W, 34.34030º S), sediment depth: 2–3 cm (holotype); water depth: 9177 m (177.65414º W, 32.85037º S), sediment depth: 0–2 cm (paratype). Description Male Body cylindrical, tapering slightly towards both extremities. Cuticle striated from level of buccal cavity to near tail tip. Somatic setae absent except for a few 1 μm long setae in pharyngeal region. Lip region slightly concave; head region otherwise rounded. Internal labial sensillae not observed. Six outer labial setae, 5 μm long, situated in separate circle from the four sensillae of third circle; the latter consists of papillae located in depressions (Fig. 3B). Small, granular glands sometimes observed, apparently connected to base of outer labial setae (Fig. 1B); larger unicellular glands also sometimes observed and apparently connected to cephalic sensillae (Fig. 2C). Four sub-cephalic setae located immediately posterior to the cephalic papillae, 3–4 μm long, similar in length or slightly shorter than outer labial setae. Large circular amphideal fovea with cuticularised outline situated 1.7 cbd from anterior body extremity. Mouth opening narrow, surrounded by bulge of inner portion of lip region; buccal cavity cylindrical, 7 μm deep, 9 μm wide, with cuticularised walls, not surrounded by pharyngeal tissue. Pharynx narrow, muscular, with oval posterior bulb; pharyngeal glands and their orifices indistinct. Nerve ring slightly posterior to middle of pharynx length. Secretory-excretory system with two or three renette cells (third cell may sometimes be obscured) all situated just posterior to pharyngeal bulb; ampulla and pore between nerve ring and posterior pharyngeal bulb. Cardia conspicuous, 90 μm long, widening posteriorly, not surrounded by intestine walls. Reproductive system diorchic with two opposed and outstretched testes, anterior testis to the left of intestine and posterior testis to the right of intestine. Mature sperm globular, nucleated, 4–5 × 6–7 μm. Spicules paired, 1.2 abd long, strongly arcuate, with well-developed capitulum and pointed distal end. Gubernaculum thin, pointed at both ends, without apophyses but with rounded glandular tissue extending dorsally. Rectal glands not observed; one ejaculatory gland situated between spicules. Pre-cloacal supplements absent. Tail long, conico-cylindrical, with rounded tip. Caudal glands not observed; short and sparse caudal setae present, no terminal setae. Intestine with numerous transparent crystalline structures, square to rhomboid-shaped, up to 14 × 14 μm (Fig. 3 C–D). Female Similar to males but with lower values of a, b, and c, slightly smaller amphids (0.42–0.44 vs 0.65 cbd) and longer tail (9.0–10.4 vs 6.4 abd). Buccal cavity 5 μm wide and 4–5 μm deep. Reproductive system didelphic; anterior branch outstretched, to the right of intestine, posteror branch poorly developed, to the left of intestine. Spermatheca present in anterior branch only, simple, not cuticularised. Vulva transverse, situated slightly posterior to mid-body; small vaginal glands present on either side of vagina; muscular pars proximalis vaginae. Juvenile Similar to females, but with shorter body and lower values of a and b. Remarks Thelonema clarki sp. nov. can be differentiated from the only other species of the genus, T. majum, by the larger body size (3230–4461 vs 1000–1460 μm), short cylindrical buccal cavity (vs long and funnelshaped in T. majum), sub-cephalic setae of similar length or shorter than outer labial setae (sub-cephalic setae longer than outer labial setae in T. majum), secretory-excretory system with two or three renette cells (secretory-excretory system not observed in T. majum), absence of gubernacular apophyses (vs dorso-caudal apophyses present in T. majum), and longer tail (6.4–10.4 vs 2.7 abd). This is the first time that Thelonema is recorded outside the type locality in the Peru Basin (~ 4150 m depth) since the original description of the genus by Bussau (1993). The genus was not included in the recent overview of all Monhysterida by Fonseca & Bezerra (2014), but the discovery of a new Thelonema species in the Southwest Pacific confirms the validity of the genus. The presence of crystalline structures in the intestine is intriguing, as many appear too large to have been ingested (the structures are up to 14 μm wide, and the width of the cuticularised buccal cavity is 4–9 μm). It seems unlikely that the buccal cavity can stretch to accommodate such large particles given the presence of cuticularised walls. The crystalline structures may have grown through accretion whilst in the intestine, but this process would presumably require a relatively long period of time.Published as part of Leduc, Daniel, 2015, New species of Thelonema, Metasphaerolaimus, and Monhystrella (Nematoda, Monhysterida) from Kermadec Trench, Southwest Pacific, pp. 1-19 in European Journal of Taxonomy 158 on pages 3-9, DOI: 10.5852/ejt.2015.158, http://zenodo.org/record/378805
Après la droite ?
No full textLeduc Victor. Après la droite ? . In: Raison présente, n°107, 3e trimestre 1993. Y-a-t-il un art contemporain ? pp. 1-3
Low- and High-Relief Leduc Formation Reefs: A Seismic Analysis
No full textLeduc reefs have grown to widely varying heights and aereal extents along the Rimbey-Meadowbrook trend of central Alberta, resulting in significantly different seismic signatures. Three examples considered in this paper include two high-relief or full reefs from the Leduc-Woodbend field, an atoll and a pinnacle, each around 200 m in height but differing greatly in areal extent, about 100 km2 for the atoll and 1 km2 for the pinnacle. The third example, a low-relief or basalt reef from the Morinville field, is about 100 m high and 1 km2 in areal extent.
The Leduc-Woodbend and Morinville reefs exhibit quite different seismic signatures. For example, 25 ms of time-structural drape along the top of the Devonian is observed across the Leduc-Woodbend atoll but only 15 ms across the Morinville reef. There is 30 ms of pullup at the Beaverhill Lake level beneath the Leduc- Woodbend atoll, 15 ms for the Morinville reef. Also, it is very difficult to differentiate the Leduc reflection from the Duvernay reflection, with which it merges, on the Morinville (basal-reef) section. In contrast, the Leduc reflection can be correlated readily on the Leduc-Woodbend atoll section; and reflections from the offreef shales (Duvernay and Ireton formations) terminate abruptly against the reef flank.
In addition, the amplitude of the underlying Cooking Lake platform reflection varies laterally, depending on the velocity of the overlying formation (Duvernay shale or Leduc reef) and, to a lesser extent, the thickness of the overlying reef. This variation is not as useful in distinguishing between low-relief and high- relief reefs as it is in indicating the presence or absence of reef
Au bord de L'Asphyxie : remarques sur l'autobiographie chez Violette Leduc
No full textLooking in the prison of her skin. notes on a utobiography in "Violette Leduc"
The impossibility of autobiography is the genre's problematic — constantly confronted with its productivity. The issue is that of the opposition between a life and a text: thus the study of an author who has systematically been read as essentially autobiographical in inspiration, at the junction between text an « off-text » : for signature, manuscript, autocitation tell the (literary) biography.Marson Susan. Au bord de L'Asphyxie : remarques sur l'autobiographie chez Violette Leduc. In: Littérature, n°98, 1995. Biographismes. pp. 45-58
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