112 research outputs found
Acanthochitona lanae Sirenko & Saito 2017, n. sp.
No full text<i>Acanthochitona lanae</i> n. sp. <p>Figs 30–32, 44 D</p> <p> <i>Acanthochitona</i> sp. Sirenko 2012: 98, pl. 14B, fig. 33.</p> <p> <b>Type material:</b> Holotype, ZISP 2233, now disarticulated consisting of mounts of shell, perinotum and radula, 30 paratypes, ZISP 2234, BL 2–13 mm and 1 paratype, NSMT-Mo 78924, BL 5 mm.</p> <p> <b>Type locality.</b> Near Da Nang, central Vietnam, 16°11.802´N, 108°10.593´E, intertidal, on barnacles.</p> <p> <b>Etymology.</b> After the first author’s colleague Dr. Chan Than Lan who organized and led our field trip and was always thinking of the members of expeditions like her own children.</p> <p> <b>Material examined.</b> Northern Vietnam, Gulf of Tongking, Cat Ba Id., 20°46.042´N, 107°05.800´E, intertidal– 1.5 m, rocks, 2 spms, BL 6–8 mm, 30.04.2012, leg. B. Sirenko; 20°44.497´N, 107°04.098´E, 5–6 m, SCUBA, on shells of <i>Pinna</i> sp. or <i>Isognomon</i> sp., 1 spm, BL 7 mm, 0 1.05.2012, leg. B. Sirenko; 20°44.497´N, 107°04.098´E, 2 m, SCUBA, on red crustose calcareous algae, 2 spms, BL 5–6 mm, 0 1.05.2012, leg. B. Sirenko; 20°47.090´N, 107°06.103´E, 1–1.5 m, SCUBA, on shells of bivalve, 1 spm, BL 3 mm, 0 1.05.2012, leg. B. Sirenko; 20°45.445´N, 107°04.693´E, 0.5–1 m, SCUBA, on shells of bivalves with red crustose calcareous algae, 4 spms, BL 6–7 mm, 0 3.05.2012, leg. B. Sirenko; 20°43.675´N, 107°03.373´E, intertidal, under stones, 5 spms, BL 5–6 mm, 10.05.2014, leg. B. Sirenko. Central Vietnam, near Da Nang, 16°11.802´N, 108°10.593´E, intertidal, on barnacles, 32 spm: holotype, BL 8 mm and 31 paratypes, BL 2–13 mm, 16.05.2012, leg. O. Savinkin; 16°09.332´N, 108°15.057´E, 7–8 m, SCUBA, on shells with barnacles, 1 spm, BL 5.5 mm, 19.05.2012, leg. O. Savinkin and E. Mekhova; Son Cha Id., 16°12.658´N, 108°12.105´E, 2–3 m, SCUBA, on small barnacles, 2 spm, BL 3–8 mm, 20.05.2012, leg. O. Savinkin; 16°12.887´N, 108°11.906´E, 0–1 m, on barnacles, 1 spm, BL 14 mm, 16.04.2013, leg. B. Sirenko;16 °12.779´N, 108°11.938´E, 0–1 m, on barnacles, 2 spms, BL 6–7 mm, 19.04.2013, leg. B. Sirenko; 16 °12.649´N, 108°11.633´E, 0–1 m, on barnacles, 12 spms, BL 6–9 mm, 20.04.2013, leg. B. Sirenko; Me Id., 19°22´59.9´´N, 105°54´52.2´´E, 6–10 m, SCUBA, on shells and stones, 1 intermediate valve, 14.04.2014, leg. O. Savinkin; 19°23´02.8´´N, 105°55´36.7´´E, 4 m, SCUBA, on shells of <i>Pinna</i> sp., 13 spms, BL 4–7 mm, 14.04.2014, leg. P. Dgebuadze; 19°21´42.7´´N, 107°19´19.7´´E, 6 m, SCUBA, on barnacles, 1 spm, BL 11 mm, 16.04.2014, leg. S. Grebelny; 19°19´11.7´´N, 105°54´30.3´´E, 2 m, SCUBA, on barnacles and oysters, 9 spms, BL 3–9 mm, 17.04.2014, leg. S. Grebelny; Son Duong Id., 18°06´23.6´´N, 106°27´35.7´´E, 1–3 m, SCUBA, on barnacles, 14 spms, BL 8–12 mm, 21.04.2014, leg. S. Grebelny. Southern Vietnam, near Dat Id., 13°41.410´N, 109°13.577´E, intertidal, on oysters, 6 spms, BL 2–4 mm, 25.04.2013, leg B. Sirenko; 13°41.037´N, 109°15.193´E, intertidal, on oysters, 2 spms, BL 3–7 mm, 28.04.2013, leg B. Sirenko.</p> <p> <b>Diagnosis.</b> Small chitons with rather wide, low intermediate valves. Jugum of longitudinal rows of fused pustules. Tail valve small, semicircular, with central, low mucro. Pustules on lateropleural areas droplet-shaped or roughly diamond-shaped, quincuncially arranged; top of pustule flat, with single macraesthete pore, 0–2 micraesthete pores around macraesthete pore and 0–2 micraesthete pores on pre-pustular slope. No micraesthete pores on tegmental plain. Dorsal side of girdle beset with minute spicules which have rather strong riblets near the tip. Sutural tufts prominent, of thick, slightly curved, smooth needles.</p> <p> <b>Description.</b> Animal small, elongate oval, low in profile. Color of tegmentum light green with brownish maculation or flecks on lateral and pleural areas; jugum white on midline bound with brown streaks at both sides. Girdle light brown with dark brownish bands around terminal valves and at sides of intermediate valves.</p> <p>Head valve semicircular, posterior margin nearly straight; anterior slope slightly convex; no radial ribs. Intermediate valves rather wide, roughly rectangular, low, round-backed, beaked; front margin almost straight; hind margin slightly concave at both sides of beak; jugum wedge-shape, comprising of longitudinal rows of fused pustules; lateral areas slightly raised. Tail valve oval, with central, low mucro; width of tegmentum equal or less than half width of valve IV; posterior slope slightly convex.</p> <p>Pustules on tegmentum rather densely distributed, arranged in quincunx order on all areas except for jugum. Each pustule flat or slightly concave at top with single macraesthete pore located slightly off centre towards prepustular slope, 0–2 micraesthete pores around macraesthete pore and 0–2 micraesthete pores on prepustular slope. No micraesthete pores on tegmental plain.</p> <p>Articulamentum rather thin, white throughout except two small light brown spots on jugal part of intermediate valves, with transverse callus in middle of valves, porous under jugum: pores arranged in 10–12 longitudinal rows which are corresponding to longitudinal rows of fused pustules on the jugum. Apophyses well projecting forward, round, widely separated from each other in intermediate valves, truncated in tail valve. Insertion plate short with short, narrow slits. Slit formula 5/1/2.</p> <p>Girdle rather wide, about 1.2 mm near valve V (width 2.7 mm), smooth in appearance. Dorsal side of girdle covered with minute spicules, 28–40 µm x 10–15 µm, somewhat flattened, with strong riblets at tip. Sutural tufts prominent, of up to 13 thick, sharply pointed, smooth or finely striate needles, which are up to 540 µm x 15 µm, surrounded by slenderer, sharply pointed, smooth spicules. Marginal needles lanceolate, depressed, up to 262 µm x 38 µm, smooth or finely ribbed. Ventral spicules small, 30–80 µm x 10–12 µm, flat, smooth, blunt at tip.</p> <p>Gills extending from valve VII to valve IV, composed of 15 ctenidia on each side.</p> <p>Radula 2.3 mm long, with 29 transverse rows of mature teeth. Central tooth with wide, almost straight cusp at top and keel at basal half. First lateral (centro-lateral) tooth with thick nodulous antero-dorsal corner. Major lateral tooth with tricuspid head; central cusp longest; cusps pointed, somewhat flattened near tips.</p> <p> <b>Distribution.</b> Northern to southern Vietnam, from 20°47.090´N to 13 °41.037´N, intertidal– 7 m.</p> <p> <b>Remarks.</b> This species differs from other <i>Acanthochitona</i> in the Indo-West Pacific area by the wide, rectangular intermediate valves which are sculptured with irregular rows of longitudinally fused pustules on the jugum, single macraesthete pore on each pustule top and the perinotum which is uniformly covered with minute, somewhat flattened spicules.</p>Published as part of <i>Sirenko, Boris I. & Saito, Hiroshi, 2017, New species of chitons of the superfamily Cryptoplacoidea (Mollusca: Polyplacophora) from Vietnamese waters, pp. 451-506 in Zootaxa 4299 (4)</i> on pages 484-489, DOI: 10.11646/zootaxa.4299.4.1, <a href="http://zenodo.org/record/836971">http://zenodo.org/record/836971</a>
Leptochiton longibranchiae Sirenko, 2015, n. sp.
No full textLeptochiton longibranchiae n. sp. (Figs 8 D, 23–26) Leptochiton sp. Schwabe & Sellanes 2010: 36 –37, Figs E–I. Types. Holotype (ZISP 2212), now disarticulated consisting of SEM stub of valves I, V, VI, VIII, part of perinotum and radula, mount of part of perinotum and radula and vial with other valves, and 15 paratypes (ZISP 2213). Type locality. Peru-Chile Trench, 12 ° 29 ’ 8 ’’S, 77 ° 32 ’ 1 ’’W, 560 m, (RV Akademik Kurchatov, cruise 4, st. 274). Etymology. The name is Latin for long line of gills. This species has very extensive row of ctenidia which is unusual for the genus Leptochiton. Material examined. Peru-Chile Trench, RV Akademik Kurchatov, cruise 4, st. 274, 12° 29 ’ 8 ’’S, 77 ° 32 ’ 1 ’’W, 560 m, holotype, BL— 8.5 mm and 15 paratypes BL— 8–15 mm; Peru, W of Hucho Lima dept. 11 °05’S, 78 ° 19.9 ’W, 400 m, 1 spm (BL— 25 mm), 15.05. 971, examined by author in LACM. Distribution. Peru and Chile from 11 °05’S to 22 ° 51 ’S, 294–560 m Diagnosis. Animal of small size. Valves lowly elevated, carinated. Tail valve wider than head valve, mucro subcentral. Tegmentum with distinct oval granules arranged in longitudinal rows on central area of intermediate valves and antemucronal area of tail valve and quincuncially in other areas. Each granule with one megalaesthete and eight surrounding micraesthetes. Dorsal scales elongate, sharply pointed, with one rib. Central teeth of radula rectangular, major lateral teeth with short unidentate distally narrowed cusp. Eighteen gills per side from valve III to anus. Description. Holotype BL— 8.5 mm. Shell widening to tail (animal ovoid in outline). Valves carinated, low (elevation ratio 0.34 in valve V), not beaked. Color of tegmentum white. Head valve semicircular, noticeably narrower than tail valve (ratio of width of tail valve to width of head valve 1.2). Intermediate valves rectangular, short and wide, anterior and posterior margins nearly straight, lateral margins rounded, not beaked, lateral areas not raised. Tail valve large with subcentral mucro, antemucronal slope straight, postmucronal slope convex. Tegmentum sculptured with distinct oval granules arranged in longitudinal chains in central areas of intermediate valves and in quincuncial pattern in other areas. Each granule with one megalaesthete and eight micraesthetes around megalaesthete, aesthete pores of megalaesthete (10 µm) a little larger than pores of micraesthetes (7–8 µm). Articulamentum moderately developed, apophyses short and wide (width of apophyses more than width of jugal sinus). Girdle relatively narrow (about 0.5 mm, near valve V, 9.3 % of total width), dorsally covered with elongate sharply pointed scales (77– 78 x 18–20 µm) with one rib. Intersegmental area with long needles (140 x 12 µm). Marginal needles shorter than sutural ones (114 x 8 µm). Girdle covered ventrally with elongate, smooth, sharply pointed scales (60 x 16 µm). Radula of holotype 4.4 mm long with 33 transverse rows of mature teeth. Central teeth rectangular, major lateral teeth with short unidentate, distally narrowed cusp. Eighteen gills per side arranged from valve III to anus. Remarks. The paratypes have different number of gills depending on body size: smallest paratype (BL— 8 mm) has 16 gills whereas the largest paratype (BL— 15mm) has 22 gills per side. Two more specimens: LASM, Peru, W of Hucho Lima dept., 11 °05’S, 78 ° 19.9 ’W, 400 m, 1 spm, (BL— 25 mm) (studied by author) and ZSM Mol 20070757, Chile off Mejillones, 22 ° 51.99 ’S, 70 ° 29.40 ’W, 294 m, 1 spm, (BL— 11 mm) (Schwabe & Sellanes, 2010) have 23 and 21 gills per side respectively, arranged from valve III to anus. This new species is easily distinguishable from many other species of the genus Leptochiton by the long line of its gills which reach to valve III, the large tail valve and the unidentate cusp of major lateral tooth. It is most similar to L. halistreptus which has an extended row of gills (24 gills arranged from valve V to anus) and a wide tail valve and it differs in having longitudinal rows on central areas of intermediate valves (quincuncially in L. halistreptus), the number of aesthetes pores (9 in L. longibranchiae and 5 in L. halistreptus), the distally narrowed cusp of major lateral teeth and in having one rib on dorsal scales (2 in L. halistreptus). From Leptochiton tenuidontus Saito & Okutani, 1990 which also has an extended row of gills L. longibranchiae differs in the number of ribs on the dorsal scales (1 in L. longibranchiae and 7–8 in L. tenuidontus), in having carinated valves (rounded in L. tenuidontus) and a distally narrowed cusp of the major lateral teeth of the radula.Published as part of Sirenko, Boris, 2015, Shallow and deep-sea chitons of the genus Leptochiton Gray, 1847 (Mollusca: Polyplacophora: Lepidopleurida) from Peruvian and Chilean waters, pp. 151-202 in Zootaxa 4033 (2) on pages 171-177, DOI: 10.11646/zootaxa.4033.2.1, http://zenodo.org/record/24161
Supplemental Material - Disadvantaged communities have lower access to urban infrastructure
No full textSupplemental Material for Disadvantaged communities has lower access to urban infrastructure by Leonardo Nicoletti, Mikhail Sirenko and Trivik Verma in Environment and Planning B: Urban Analytics and City Science</p
The Exact Absorbing Conditions Method in the Analysis of Open Electrodynamic Structures
No full textThe authors expound the method of exact absorbing boundary conditions, which solves one of the most important theoretical problems in computational electrodynamics, namely, the problem of equivalent replacement of an open (with infinite domain of analysis) initial boundary value problem by a closed (with bounded computation domain) one. This method, being mathematically strict, allows proper formulation and numerical study of transient and steady-state processes in various open resonant systems. The authors present local (in space and time) and non-local exact absorbing conditions for virtual boundaries located in cross-sections of regular waveguides or in free space. The elaborated concept of the so-called virtual feeding waveguides allows to solve many practically interesting radiation problems. The approach outlined in this chapter was implemented in software for solving both scalar (plane and axially symmetric) and vector problems
Effect of Beta - Blockers on Insulin Resistance in Patients with Hypertension and Metabolic Syndrome after 6 Months of Treatment
No full textYuriy Konstantinovich Sirenko (to the 70th anniversary of his birthday)
No full text26 июня 2019 года исполнилось 70 лет со дня рождения талантливого ученого, доктора физико-математических наук, профессора, лауреата Государственной премии в области науки и техники, главного научного сотрудника ИРЭ им. А.Я. Усикова НАН Украины, члена редколлегии журнала «Радиофизика и электроника» Юрия Константиновича Сиренко
Yuriy Konstantinovich Sirenko (to the 70th anniversary of his birthday)
No full text26 июня 2019 года исполнилось 70 лет со дня рождения талантливого ученого, доктора физико-математических наук, профессора, лауреата Государственной премии в области науки и техники, главного научного сотрудника ИРЭ им. А.Я. Усикова НАН Украины, члена редколлегии журнала «Радиофизика и электроника» Юрия Константиновича Сиренко
High-Power Short Pulses Compression: Analysis and Modeling
No full textThe chapter discusses practically realizable algorithms of model synthesis of direct-flow compressors built on the basis of rectangular, circular or coaxial waveguides. Resonance and distributed switches have been designed to ensure effective energy accumulation and release into output waveguides or free space. The authors dwell on peculiarities of radiation of high-power short pulses by simple monopole antennas with coaxial feeding waveguides. They also design a novel phased antenna array, whose each radiating element is an active compressor. Particular attention is given to the study of such physical processes in compressors as energy accumulation, switching from the accumulation mode into the mode of energy release, and radiation of short high-power pulses into free space
Electromagnetic waves in complex systems: selected theoretical and applied problems
No full textThis book gives guidance to solve problems in electromagnetics, providing both examples of solving serious research problems as well as the original results to encourage further investigations. The book contains seven chapters on various aspects of resonant wave scattering, each solving one original problem. All of them are unified by the authors’ desire to show advantages of rigorous approaches at all stages, from the formulation of a problem and the selection of a method to the interpretation of results. The book reveals a range of problems associated with wave propagation and scattering in natural and artificial environments or with the design of antennas elements. The authors invoke both theoretical (analytical and numerical) and experimental techniques for handling the problems. Attention is given to mathematical simulations, computational efficiency, and physical interpretation of the experimental results. The book is written for students, graduate students and young researchers.
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