189,331 research outputs found
A decomposition method for the approximate evaluation of capacitated transfer line with unreliable machines and random processing times
No full textTitle from cover.Bibliography: p. 19.by Yong F. Choong, Stanley B. Gershwin
Simulation of a flexible manufacturing system
No full textBibliography: p. 39."March, 1985."Ramakrishna Akella, J. Patrick Bevans, and Yong Choong
Sertularella sacciformis Choong, 2015, sp. nov.
No full text<i>Sertularella sacciformis</i> sp. nov. <p>(Figure 7)</p> <p> <b>Material</b>. <b>Holotype:</b> CANADA: British Columbia. Hecate Strait, Gwaii Haanas National Marine Park Reserve, 53˚32’48”N, 131˚19’30”W, 26. ix.1985, 26 meters, coll. R.O. Brinckhurst, hydrocaulus section, without gonothecae, ROMIZ B2341. <b>Paratype:</b> CANADA: British Columbia. 54˚13’00”N, 132˚09’00”W, 29.iv.1961, 98.8 meters, coll. D.B. Quayle, hydrocauli sections, without gonothecae, ROMIZ B4070.</p> <p> <b>Reported distribution</b>. CANADA: British Columbia, Vancouver island, off Clayoquot Sound as <i>Sertularella rugosa</i>.</p> <p> <b>Description</b>. Hydrocaulus flexuous, stem geniculate; axis divided into internodes. Perisarc thin throughout. If present, ramifications arise from axis directly under axillary hydrotheca on same plane or angled perpendicularly. Ramification structure same as axis. Beginning of internode marked with two or three well-marked, oblique annular constrictions of perisarc. Internode segments narrowed basally, widening distally. Hydrothecae alternate, distant, one per internode on upper part, on same plane or slightly inclined, following ramification orientation; shape distinctly saccate basally, narrow distally. Saccate shape asymmetrical, adcauline side prominently protuberant. Adcauline wall approximately ¼ adnate, basal part of free portion fairly straight or moderately concavo-convex, distally inclined towards adcauline side. Distal portion of adcauline wall also slightly inclined outwards, forming slight concavity. Hydrothecae strongly annulated basally; apex of 3–4 annulations forming ribs or uneven, crested folds, widening towards adcauline side. Distal part of hydrothecae smooth, giving appearance of cylindrical neck, widening basally. Opercular opening rectangular, embayments shallow but flared, meeting to form four prominent cusps. Operculum of four triangular flaps, forming a low peak when closed. Intrathecal cusps not present. Gonothecae not found.</p> <p> <b>Differential diagnosis</b>. Due to the occasionally acute angle of the outward bend, the square-shaped hydrothecal aperture, and the general rugosity of the perisarc, the hydrothecae of <i>Sertularella sacciformis</i> can resemble those of <i>S. rugosa</i> (Linnaeus, 1758) or <i>S. tenella</i>. ROMIZ B2341 was originally identified as <i>S. rugosa</i>, but <i>S. rugosa</i> lacks the smooth hydrothecal neck found in <i>S. sacciformis</i>. The absence or presence of a notch below the rim on the abcauline wall of the hydrotheca as seen from the side is considered to be a diagnostic feature separating <i>S. rugosa</i> from its congeners, although its systematic value has been questioned by some authors (Cornelius 1979, 1995; Schuchert 2001). Nevertheless, in <i>S. sacciformis</i> this notch is absent, although the appearance of a notch is occasionally approximated by the abcauline incline of the hydrothecal neck and the tumidity of the basal portion. This gives appearance of a notch, but the area below the hydrothecal rim is actually straight. In <i>S. tenella</i>, the hydrotheca resembles a broad-necked bottle, rather than the saccate, bent-neck shape of <i>S. sacciformis</i>. The nature of the rugosity is also different in all three species. In <i>S. rugosa</i> the encircling transverse ridges are sharp, forming deep furrows, which are especially marked on the abcauline side; in <i>S. tenella</i>, the sharp ridges which encircle the hydrotheca appear more evenly spaced, but in <i>S. sacciformis</i>, the annular segments form uneven, crested folds, widening towards the adcauline side. Moreover, in <i>S. rugosa</i> the colony tends to be poorly ramified on a single plane (Naumov 1969). In <i>S. sacciformis</i>, the stem is slender, and the hydrothecae are not as closely spaced as in <i>S. rugosa</i>.</p> <p> <b>Etymology</b>. The species name refers to the shape of the hydrothecae, from the Latin <i>saccus</i> (sack or pouchshaped).</p>Published as part of <i>Choong, Henry H. C., 2015, Hydroids of the genus Sertularella (Cnidaria: Hydrozoa: Sertulariidae) from the Pacific coast of Canada in the collection of the Royal Ontario Museum, with descriptions of four new species, pp. 387-408 in Zootaxa 3925 (3)</i> on pages 402-404, DOI: 10.11646/zootaxa.3925.3.4, <a href="http://zenodo.org/record/236318">http://zenodo.org/record/236318</a>
Sertularella pacifica Choong, 2015, sp. nov.
No full text<i>Sertularella pacifica</i> sp. nov. <p>(Figure 6)</p> <p> <i>Sertularella fusiformis</i> — Torrey, 1902: 61, pl. 6, fig. 53–54.— Fraser, 1937: 153, pl. 34, fig. 181 [not <i>Sertularella fusiformis</i> (Hincks, 1861)]</p> <p> <b>Material</b>. <b>Holotype:</b> CANADA: British Columbia. Vancouver Island, Juan de Fuca Strait, Race Rocks, 48˚18’00”N, 123˚32’00”W, 0 5. iv.1986, 6–10 meters, two short hydrocauli, with gonothecae, coll. A. Brinckmann- Voss, ROMIZ B670. <b>Paratype:</b> CANADA: British Columbia. Queen Charlotte Land District. Masset Harbor, 14. ix.1935, without gonothecae, ROMIZ B4065. <b>Other material:</b> CANADA: British Columbia. Queen Charlotte Land District. Masset Harbor, 54˚03’00”N, 132˚13’00”W, 14. ix.1935, colony arising from stolon at the base of <i>Abietinaria pulchra</i> (Nutting, 1904) colony, without gonothecae, ROMIZ B4066. CANADA: British Columbia. Queen Charlotte Land District. Masset Harbor, 14. ix.1935, two short hydrocauli, without gonothecae, ROMIZ B4067. CANADA: British Columbia. Queen Charlotte Land District. Masset Harbor, 14. ix.1935, colony arising from stolon at the base of <i>Sertularia</i> sp.colony, without gonothecae, ROMIZ B4068. CANADA: British Columbia. Queen Charlotte Land District. Masset Harbor, 54˚03’00”N, 132˚13’00”W, 14. ix.1935, hydrocauli, without gonothecae, ROMIZ B4069.</p> <p> <b>Reported distribution</b>. California: San Francisco, as <i>Sertularella fusiformis</i> (Hincks, 1861) (Torrey, 1902). Oregon: Three locations off Heceta Head, 0–113 meters (Fraser, 1937).</p> <p> <b>Description.</b> Colonies erect, hydrorhiza stolonal, occasionally anastomosing. Hydrocaulus geniculate, unbranched. Perisarc thickened throughout, up to 60 mm thick. Hydrocaulus monosiphonic, unfascicled, divided into internodes. Internodes 1003–1530 mm long, with one to three (usually two) complete annulations basally; proximal-most annulation often spirally twisted (Fig. 3 A,B). Internode has tendency to spiral relative to main axis. Single hydrotheca distal to internode. Hydrothecae alternate, often not on same plane (Fig. 3 A). Hydrotheca tubular, walls asymmetrical; abcauline and adcauline wall slightly swollen basally, swelling on abcauline wall more proximal. Perisarc of hydrothecae thickened, up to 60 mm thick. Distal half of hydrotheca narrowed towards aperture, greater narrowing on abcauline side. Adcauline hydrothecal wall adnate for approximately 1/4–1/2 of length. Hydrothecal margin dentate with four equally-developed cusps; one adcauline, one abcauline, and two laterals. Opercular flaps triangular, four present; when closed forms roof extending slightly beyond opercular margin. Intrathecal cusps present, three in number, occasionally missing; two small intrathecal cusps proximal to and flanking adcauline marginal cusp, one long and narrow intrathecal cusp on abcauline side (Fig 3 A).</p> <p>Gonothecae (♂) few, attached to internode or directly below base of hydrotheca; large, up to three-times longer than hydrothecae, spindle-shaped, widest medially, longer than wide, flexed or bent mid-axis. Gonothecal body strongly annulated throughout; 10–12 complete, well-developed annulations. Neck short or barely discernible, four low rounded cusps around gonothecal aperture. Occasionally, one of the four cusps may be more developed than other three.</p> <p> <b>Differential diagnosis</b>. The records from the west coast of North America (Torrey 1902; Fraser 1937) seem to be morphologically distinct from descriptions of <i>S. fusiformis</i> elsewhere as shown by the absence of four intrathecal cusps and the presence of two annulations at the base of the internodes. These descriptions correspond to the specimens examined by the author in this study. Given the variability of the species included in the <i>S. fusiformis</i> / <i>S.ellisii</i> complex, this species was most likely misidentified as <i>S. fusiformis</i>. Measurements of the internodes, hydrothecae, and gonothecae (Table 4) show that these specimens are much larger than <i>S. fusiformis</i>. The intrathecal cusps are never as well-developed as in <i>S. fusiformis.</i> Moreover, the hydrothecae of <i>Sertularella pacifica</i> <b>sp. nov.</b> lack the considerably swollen basal portion and strongly tapered upper portion characteristic of the fusiform hydrothecal shape, and the gonothecae are distinct from those belonging to <i>S. fusiformis</i> in being spindle-shaped and bent around their mid-axis.</p> <p> <b>Remarks</b>. This material agrees with the hydroids attributed to <i>Sertularella fusiformis</i> (Hincks, 1861) from the west coast of North America by Torrey (1902), and subsequently included in reports by Fraser (1911, 1937). <i>Sertularella fusiformis</i> is well distributed in temperate and subtropical parts of the Atlantic as well as in the Mediterranean, but records of occurrences elsewhere are few and dispersed (Ramil <i>et al</i>. 1992). The latter are from the Indian Ocean coast of South Africa (Millard 1975) and from the Pacific coast of North America: Californian Pacific coast (Fraser 1911); off Heceta Head, Oregon (Fraser 1937). I consider the reports of <i>Sertularella fusiformis</i> from the Pacific coast of North America to be erroneous. Its biogeographic distribution, and the distinct morphological characteristics of <i>Sertularella pacifica</i> set this species apart from its congeners. Even within the Atlantic, it is probable that the nominal species <i>Sertularella fusiformis</i> is part of a species complex. <i>Sertularella fusiformis</i>, along with <i>S. mediterranea</i>, <i>S. ellisii</i>, <i>S. ornata</i>, and <i>S. polyzonias</i> are morphologically similar and so have been variously kept separate or synonymised with other taxa (Cornelius 1979; Ramil <i>et al.</i> 1992; Medel & Vervoort 1998). Millard (1958) considered <i>S. fusiformis</i> to be a variable species, but accepted the diagnostic value of the presence of 4 intrathecal cusps that alternate with the marginal cusps in this species, a view shared by Corrales <i>et al.</i> (1980). Others, such as Picard (1956) considered <i>S. fusiformis</i> to be an extreme, Atlantic form of <i>S. ellisii</i>. 16S genetic data has provided evidence that nominal species of <i>Sertularella fusiformis</i> from Madeira and the Azores in the North Atlantic fall into distinct clades likely corresponding to different species (Moura <i>et al.</i> 2011).</p> <p> <b>Etymology</b>. The species name refers to the Pacific Ocean and emphasizes its distinctiveness from its congeners elsewhere.</p>Published as part of <i>Choong, Henry H. C., 2015, Hydroids of the genus Sertularella (Cnidaria: Hydrozoa: Sertulariidae) from the Pacific coast of Canada in the collection of the Royal Ontario Museum, with descriptions of four new species, pp. 387-408 in Zootaxa 3925 (3)</i> on pages 399-400, DOI: 10.11646/zootaxa.3925.3.4, <a href="http://zenodo.org/record/236318">http://zenodo.org/record/236318</a>
Protosticta joepani sp. nov. from Borneo with notes on P. kinabaluensis Laidlaw 1915 (Odonata: Zygoptera: Platystictidae)
No full textDow, Rory A., Phan, Quoc Toan, Choong, Chee Yen (2020): Protosticta joepani sp. nov. from Borneo with notes on P. kinabaluensis Laidlaw 1915 (Odonata: Zygoptera: Platystictidae). Zootaxa 4729 (3): 371-387, DOI: https://doi.org/10.11646/zootaxa.4729.3.
sj-xlsx-1-ijm-10.1177_02557614231179221 – Supplemental material for The applicability of Anglosphere-based popular music learning culture characterisations to a Malaysian context
No full textSupplemental material, sj-xlsx-1-ijm-10.1177_02557614231179221 for The applicability of Anglosphere-based popular music learning culture characterisations to a Malaysian context by Hueyuen Choong in International Journal of Music Education</p
Short term production scheduling of an automated manufacturing facility
No full textBibliography: p. 36."February, 1984."Contract DAAK11-82-K-0018.Stanley B. Gershwin, Ramakrishna Akella, and Yong Choong
Performance of hierarchical production scheduling policy
No full text"February, 1984."Bibliography: p. 29.NASA Grant No. NAG1-2by Ramakrishna Akella, Yong Choong and Stanley B. Gershwin
Conductivity and thermopower in P-doped a-Si:H prepared by DC glow discharge decomposition
No full text학위논문(석사) - 한국과학기술원 : 물리학과, 1981.2, [ ii, 33 p. ]한국과학기술원 : 물리학과
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