43 research outputs found
TAXONOMIC REVISION OF THE FERN GENUS CTENITIS (DRYOPTERIDACEAE) FROM AFRICA AND THE WESTERN INDIAN OCEAN
No full textA taxonomic revision of Ctenitis (C. Chr.) C. Chr. (Dryopteridaceae) from Africa and the Western Indian Ocean was carried out. Forty species are recognized, of which 12 are described as new, eight are transferred to Ctenitis from other genera, and one is elevated from variety to species and transferred from Aspidium Sw. to Ctenitis. These 21 nomenclatural novelties include C. analamazaotrensis (Rakotondr.) Hennequin & Rouhan (comb. nov.), C. brevipetiolulata Li Bing Zhang & Yi F. Duan (sp. nov.), C. bullescens Rouhan, Li Bing Zhang & Yi F. Duan (sp. nov.), C. cerea Li Bing Zhang & Yi F. Duan (sp. nov.), C. comorensis Li Bing Zhang & Yi F. Duan (sp. nov.), C. crinigera (C. Chr.) Hennequin & Rouhan (comb. nov.), C. decaryana (C. Chr.) Hennequin & Rouhan (comb. nov.), C dentata Li Bing Zhang & Yi F. Duan (sp. nov.), C. fibrillosa (Baker) Li Bing Zhang & Yi F. Duan (comb. nov.), C. hispida (Kuhn) Li Bing Zhang & Yi F. Duan (comb. & stat. nov.), C. jouyana (Rakotondr.) Hennequin & Rouhan (comb. nov.), C. longivillosa Li Bing Zhang & Yi F. Duan (sp. nov.), C. marginalisora Li Bing Zhang & Yi F. Duan (sp. nov.), C mayottensis Li Bing Zhang & Yi F. Duan (sp. nov.), C. multilobata Li Bing Zhang, Yi F. Duan & Rouhan (sp. nov.), C. reunionensis Hennequin, Li Bing Zhang & Yi F. Duan (sp. nov.), C. sieberiana (Kaulf.) Hennequin & Rouhan (comb. nov.), C sparsa Li Bing Zhang & Yi F. Duan (sp. nov.), C. spekei (Baker) Li Bing Zhang & Yi F. Duan (comb. nov.), C. subcrenulata (Baker) Li Bing Zhang, Rouhan & Yi F. Duan (comb. nov.), and C tardieu-blotiae Li Bing Zhang & Yi F. Duan (sp. nov.). A key to these species is provided; all species are described and illustrated; and information on their distribution and habitats is given. Twenty-three relevant species reported in the literature are excluded from the flora, and their taxonomy, distribution, and nomenclature are discussed. Seventeen related names are lectotypified or neotypified including Aspidium cirrhosum Schumach., A. crinitum (Poir.) Wall. var. hispida Kuhn, A. cyclochlamys Fee, A. nitidum Bory ex Willd., A. pauciflorum Kaulf., A. sulcatum Kaulf. ex Bory, C. anjenabensis Tardieu, Dryopteris blepharochlamys C. Chr., Gymnogramma subsimilis Hook., Nephrodium crinitum (Poir.) Desv. var. maritimum Cordem, N.. magnum Baker, N. spekei Baker, N. welwitschii Baker, Phegopteris biformis Mett. ex Kuhn, P. bivestita Mett., Polypodium baronii Baker, and P. efulense Baker; type information of related 262 names is also given
Present and past occurrence of members of the genus Filinia Bory de St. Vincent, 1826 (Testudinellidae Rotatoria) in Lake Balaton
No full textFilinia (active state) inhabits the open water of Lake Balaton in the
cold-water season (1902-1973). Neither figures nor measurements referring
to single individual exists on Balaton Filinia with the exception of population
No 423 (18. 1. 1956), which proved to be a homogenous one of the taxon
Filinia terminális Plate 1866 f. maior Colditz 1914.
Resting eggs are known from both plankton and neuston. Remains from
the sediments showing th at Filinia inhabits Lake Balaton continuously since
the initial period of the formation of Lake Balaton. This suggests that environmental
conditions were always suitable for floating forms viz. plankton.
Attention is called 1. to investigate recent populations in Lake Balaton
using modern key to clear up taxonomic relation on a broader basis (Pejler ,
Hutchinson, Ruttner-Kolisko), 2. on the importance of the winterplankton
in this shallow and throughout the year well aerated lake by reinvestigating
the observations of Náday, the author first noting Filinia in
this lake
Phlegmariurus wilsonii B. Ollgaard 2012
No full text. Phlegmariurus wilsonii (Underwood & F.E Lloyd) B. Øllgaard (2012a: 481). Fig. 20 Lycopodium wilsonii Underwood & F.E Lloyd (1906: 111).— Urostachys wilsonii (Underwood & F.Lloyd) Herter (1923: 163).— Huperzia wilsonii (Underwood & F.E Lloyd) B.Øllgaard (1987: 170). Type:— PUERTO RICO: Luquillo Mountains, Wilson 153 (NY lectotype, here designated). Note: According to the protolog the type is Wilson 271, but Wilson 153 (NY) is annotated by the author as sp. nov. and fits the description, while Wilson 271 (NY) is Phlegmariurus dichotomus and is not annotated as sp. nov. Lycopodium andinum Herter (1909a: 49) non Rosenstock (1908: 239).— Lycopodium lindavianum Herter (1909b: 90).— Urostachys lindavianus (Herter) Nessel (1939: 146).— Huperzia lindaviana (Herter) Holub (1985: 74). Type:— ECUADOR: “In territorio rei publ. Ecuador”, Fraser s.n. (P [Herb. Drake] lectotype, designated by Øllgaard 1988: 97; isotype, G). Lycopodium trichodendron Herter (1909a: 49).— Urostachys trichodendron (Herter) Herter (1923: 163). Type:— GUADELOUPE: L’Herminier s. n. (P00559253), Bory 103 (P00559254, syntypes). Lycopodium stamineum Maxon (1912: 2).— Urostachys stamineus (Maxon) Nessel (1939: 148). Type:— PANAMÁ. Chiriquí: Upper Caldera watershed, betrween Camp I and the Divide, Holcombs Trail, above El Boquete, ca. 1750 m, Maxon 5636 (US 676085 holotype). Lycopodium arcanum Maxon (1938: 310). Type:— HONDURAS: Comayagua, above El Achiote, above plains of Siguatepeque, 1800 m, Yuncker, Dawson & Youse 6149 (US holotype). Urostachys mandiocanus (Raddi) Herter var. filifolius Herter (1954: 124). Type:— ECUADOR: Eastern slope of eastern cordillera, bank of Palora river, 1500 m, Rimbach 125 (US holotype). Plants erect, arcuate-spreading to pendulous, to 20 (–30) cm long. Shoots homophyllous, 1.5–2.5 (–3) cm in diameter including leaves, equally thick throughout, or in some slender individuals gradually tapering to 1–1.5 cm in terminal divisions. Stems excluding leaves (1–) 1.5–2 (–3) mm thick at the base, often tapering to (0.7–) 1 mm, prominently ridged by decurrent leaf bases, pale green to stramineous, often with bright red spots on leaf bases, sporangiate, often in seasonally produced zones, from 5–15 cm above the base and upward, 3–6 (–9) times dichotomous. Leaves usually uniform throughout, borne in alternating, often irregularly oblique whorls of 6–7, these 0.5–1.5 mm apart in basal divisions, upward often in whorls of 4–5, forming 8–14 indistinct longitudinal ranks, perpendicularly spreading to ascending, straight to upward curved, usually not twisted at the base, linear to filiform, (6–) 10–17 × 0.3–0.5 mm, quickly narrowed to ca. 0.2 mm wide due to involution, gradually tapering toward the tip, adaxially canaliculate to involute, often with a prominent vein abaxially near the base. Leaves of terminal divisions in old plants sometimes gradually reduced to 6(–4) mm long. Decurrent leaf bases usually not wider than the lamina base, often bright red. Sporangia 1–1.5 mm wide. Distribution:— Mexico (Oaxaca) to Panamá, West Indies, northern South America south to Bolivia, Brazil (Mato Grosso). Habitats: —Epiphytic (rarely terrestrial) in montane forest, elev. 900–1900 m elev. Usually an erect epiphyte, but sometimes becoming pendulous when very large; often with bright red, but usually not prominent leaf bases. Notes:— Phlegmariurus wilsonii is related to P. dichotomus, P.mandiocanus (Raddi 1819: 280) B. Øllgaard (2012a: 480) from Brazil, and P. pithyoides (Schld. & Cham.) B.Øllgaard from Central America, Hispaniola, Colombia, and Venezuela. With these it shares the bottle-brush-like aspect, and with the latter two the bright red coloration of the leaf bases. Pendulous individuals of P. wilsonii are rather similar to P. polycarpos, but the latter has shorter, more flattened, leaves, and uniformly falcate leaves due to a basal twist, and this species apparently is always pendulous. Pendulous individuals of P. wilsonii may be separated from P. watsonianus by the lack of auricles at the lamina base. The absence or presence of red colour on the leaf bases seems uncorrelated with other characters. The intensity and size of the coloration is also variable. The direction of leaves is correlated to growth habit. In erect-growing plants the leaves are wide-spreading to slightly reflexed, while in pendent plants the leaves are somewhat ascending. Specimens studied:—Chiriquí: Bajo Chorro, Boquete, 1830 m, Davidson 230 (F, MO, US). Palo Alto, 4.5 mi NE of Boquete, forest along W branch of headwaters of Río Palo Alto, 1920 m, Hammel 7304 (MO). Above El Boquete, 1750 m, Maxon 5636 (US). Along trail between north fork of Río Palo Alto and Cerro Pate Macho, ca. 6 km NE of Boquete, 1600–2000 m, Smith 2414 (UC). Camino campamento de Fortuna sitio de presa—Trocha 3 de noviembre, entre Santa María y Pinola, 1000–1200 m, Correa et al. 2926 (PMA). Parque Nacional Volcán Barú, Alto Chiquero, 893 m, Mello-Silva et al. 3350 (PMA).Published as part of Øllgaard, Benjamin & Testo, Weston, 2021, --- The- -- Lycopodiaceae- -- of- -- Panamá, pp. 1-66 in Phytotaxa 526 (1) on pages 45-46, DOI: 10.11646/phytotaxa.526.1.1, http://zenodo.org/record/572318
Glória póstuma :: almanaque objeto de estudo /
No full textDissertação (Mestrado) - Universidade Federal de Santa Catarina, Centro de Comunicação e Expressão.Análise da revista Almanaque-cadernos de literatura e ensaio, centrada em seus sete primeiros números, publicados pela Editora Brasiliense e organizados por Walnice Nogueira Galvão e Bento Prado Jr., de 1976 a 1976 a 1978. A partir dos manifestos de crítica literária presentes nessa primeira fase da revista, a dissertação busca respostas para as questões presentes no título: a relação entre discurso acadêmico e indústria cultural, cadernos de literatura e ensaio e almanaques, mapeando as posições defendidas e as alternativas vislumbradas pela crítica literária brasileira no final dos anos 70. A dissertação inclui ainda a indexação completa dos quatorze números do periódico, desenvolvida no banco de dados do projeto "Poéticas contemporâneas: histórias e caminhos", do Núcleo de Estudos Literários e Culturais (NELIC), na UFSC
Lithium fluoride injection layers can form quasi-Ohmic contacts for both holes and electrons
No full textThin LiF interlayers are typically used in organic light-emitting diodes to enhance the electron injection. Here, we show that the effective work function of a contact with a LiF interlayer can be either raised or lowered depending on the history of the applied bias. Formation of quasi-Ohmic contacts for both electrons and holes is demonstrated by electroluminescence from symmetric LiF/polymer/LiF diodes in both bias polarities. The origin of the dynamic switching is charging of electrically induced Frenkel defects. The current density-electroluminescence-voltage characteristics can qualitatively be explained. The interpretation is corroborated by unipolar memristive switching and by bias dependent reflection measurements. (C) 2014 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution 3.0 Unported License
Relation between the electroforming voltage in alkali halide-polymer diodes and the bandgap of the alkali halide
No full textElectroforming of indium-tin-oxide/alkali halide/poly(spirofluorene)/Ba/Al diodes has been investigated by bias dependent reflectivity measurements. The threshold voltages for electrocoloration and electroforming are independent of layer thickness and correlate with the bandgap of the alkali halide. We argue that the origin is voltage induced defect formation. Frenkel defect pairs are formed by electron-hole recombination in the alkali halide. This self-accelerating process mitigates injection barriers. The dynamic junction formation is compared to that of a light emitting electrochemical cell. A critical defect density for electroforming is 10(25)/m(3). The electroformed alkali halide layer can be considered as a highly doped semiconductor with metallic transport characteristics. (C) 2014 Author(s)
Charge trapping at the polymer- metal oxide interface as a first step in the electroforming of organic-inorganic memory diodes
No full textImproving the d33 and g33 properties of 0-3 piezoelectric composites by dielectrophoresis
No full textComposites of piezoelectric particles in a polymer matrix with enhanced properties in the poling direction were prepared by dielectrophoretic alignment of the particles. The effect of processing parameters such as the amplitude and frequency of the applied electric field and the viscosity of the matrix on the dielectric and piezoelectric properties of the cured composite were demonstrated for a composite with a PZT volume fraction of 0.2. The amount of structuring could be correlated to the dielectric and piezoelectric properties of the composite through the order parameter for the average particle chain orientation, which was derived from image analysis of the microstructure. The piezoelectric properties of the aligned composites can be described with a new model for composites containing particles arranged into chains. The model predictions are in good agreement with the experimental results.Aerospace Materials & ManufacturingAerospace Engineerin
Electrical conduction of LiF interlayers in organic diodes
No full textAn interlayer of LiF in between a metal and an organic semiconductor is commonly used to improve the electron injection. Here, we investigate the effect of moderate bias voltages on the electrical properties of Al/LiF/poly(spirofluorene)/Ba/Al diodes by systematically varying the thickness of the LiF layer (2-50¿nm). Application of forward bias V below the bandgap of LiF (V
