10,943 research outputs found
Author Correction: Evaluation of skin cancer resection guide using hyper‑realistic in‑vitro phantom fabricated by 3D printing
No full textThe original version of this Article contained an error in the spelling of the author Taehun Kim which was incorrectly given as Teahun Kim. The original Article has been corrected
Author Correction: El Niño–Southern Oscillation complexity (Nature, (2018), 559, 7715, (535-545), 10.1038/s41586-018-0252-6)
No full textIn this Review, the middle initial of author Kim M. Cobb was omitted. The original Review Article has been corrected online. © 2019, The Author(s), under exclusive licence to Springer Nature Limited.11Nsciescopu
M/NEM devices and uncertainty quantification
No full textSubmission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2020-05-01The student, Namjung Kim, accepted the attached license on 2018-01-19 at 10:43.The student, Namjung Kim, submitted this Dissertation for approval on 2018-01-19 at 11:49.This Dissertation was approved for publication on 2018-01-23 at 13:14.Recent advances in computing power have facilitated the use of computational simulations as design guidelines in a range of fields including the semiconductor industry, biosensors, microfluidic devices, and even nano-sized devices. Although simulation can capture the physics behind the experiment, deterministic simulations with parameters derived from least-square fitting are significantly limited for understanding output distributions from experiments. This deviation between computational simulation and experiment may arise for a number of reasons: the stochastic nature of design parameters, external environmental fluctuations, measurement noise, and so forth. These are called uncertainties. Understanding the effect of these uncertainties is important in manufacturing processes, because manufacturing processes incorporate multi-scale and multi-physics sub-steps, with uncertainties in inputs accumulated and propagated through the sub-steps, resulting in significant deviations in the performance of final products.
A systematic approach to understanding the variations in the output from various uncertainty sources is called uncertainty quantification (UQ). To integrate uncertainty quantification fully into the design process, the sources of uncertainty must be identified and quantified; then, the uncertainty needs to be characterized and parameterized to create a statistical model. The parameterized statistical model is fed into a physics-based deterministic model (e.g., a finite element model) to quantify the deviations in the final products arising from the uncertainty parameters. By understanding the effect of stochastic parameters in inputs as well as manufacturing processes, computational simulations can provide more reliable design guidelines across a range of manufacturing fields.
This dissertation consists of two parts. The first part describes how simulation can assist in understanding experimental results. The specific physical systems considered in this dissertation are a MEMS-based resonator (Chapter 2) and a microfluidic device (Chapter 3). The results show that simulation is a powerful tool for describing details of experimental results that cannot be explained easily due to the complexity of the systems. However, distinctive discrepancies between the results from current computational predictions and experiments still exist, especially when various uncertainties are present. Therefore, the second part of this dissertation is devoted to developing a systematic approach to modeling stochastic input variables through experimental data, and describing how this can be incorporated into a modeling framework.
This dissertation suggests a systematic approach to developing a finite element model that can estimate the mechanical properties of final products with spatial uncertainties in the 3D printing process (Chapter 4), and those arising from variations in microstructure in the die-casting process (Chapter 5). Those input uncertainties are extracted from the images of final products. The data-driven modeling approach with Gaussian process is proposed to consider the probabilistic behavior of uncertainties. The realizations sampled from the calibrated Gaussian process model are incorporated into the deterministic model, generating more realistic simulation model. The systematic approach developed in this study can assist in understanding the effect of input uncertainties on the variance of the mechanical performance of final products from 3D printing and die-casting. This approach will be beneficial to other manufacturing processes where input uncertainties are important.DSpace SAF Submission Ingestion Package generated from Vireo submission #12016 on 2018-08-31 at 17:24:37Made available in DSpace on 2018-09-04T20:46:44Z (GMT). No. of bitstreams: 3
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DNS of turbulent mixing layers with variable density
No full textWe present some preliminary results of direct numerical simulations of three-dimensional, temporal, plane mixing layers with variable density. The simulations are run with a parallel in-house code that solves the Navier-Stokes equations in the Low-Mach number approximation, using a novel algorithm based on an extended version of the velocity-vorticity formulation used by Kim, Moin & Moser (1987) for incompressible flows. The simulations are run with Pr=0.7 and achieve Re_lambda=90-110 during the self-similar evolution of the mixing layer. Four cases with density ratios s=1,2,4 and 8 are presented. Our results show good agreement with previous experimental and numerical studies, and allow us to characterize the scales in the temperature spectra
Stygiopontius horridus Lee & Kim & Kim 2020, n. sp.
No full text<i>Stygiopontius horridus</i> n. sp. <p>(Figs 13–16)</p> <p>http://zoobank.org/ C29CE293-4E24-4182-A215-D555443CA734</p> <p> <b>Material examined.</b> Twenty three females, eight males, and one copepodid I in amplexus with a male adult, from washings of invertebrates at GTV1702 (19°33.387´S, 65°50.893´E, depth 2507 m), the Solitaire vent field on the Central Indian Ridge in the Indian Ocean, 01 August 2017. Holotype (female, MABIK CR00244731) and paratypes (20 females and seven males, MABIK CR00244732) have been deposited in the Marine Biodiversity Institute of Korea (MABIK), Seocheon. Dissected paratypes (two females and one male) are retained in the collection of the junior author.</p> <p> <b>Additional material examined.</b> Seven females and two males from washings of invertebrates, at GTV 1807 (19°33.395´S, 65°50.889´E, depth 2634 m), the Solitaire vent field, 20 June 2018.</p> <p> <b>Female.</b> Body (Fig. 13A) moderately broad and 1.24 mm long. Prosome 710 × 545 μm. Cephalothorax 445 μm long, with angular posterolateral corners. Three metasomites with rounded posterolateral corners. Urosome (Fig. 13B) 5-segmented. Fifth pedigerous somite 149 μm wide; lateral apices not pointed. Genital double-somite 190 × 163 μm, distinctly longer than wide, with slightly expanded anterior two-fifths; genital aperture located dorsolaterally at 30% region of double-somite length. Three free abdominal somites 73 × 104, 49 × 99, and 46 × 98 μm, respectively, smooth without spinules or setules on all surfaces. Caudal rami (Fig. 13C) stout and slightly convergent; each ramus 72 × 42 μm, 1.71 times as long as wide, with tapering posteroventral margin and six naked setae; innermost distal seta as long as outermost distal seta. Egg sac (Fig. 13D) containing two or three eggs; each egg about 195 μm in diameter.</p> <p>Rostrum absent.Antennule (Fig. 13E) relatively short, 273 μm long, and 10-segmented; third segment short and incompletely articulated from second segment; first segment the longest; armature formula 15, 8, 2, 4, 2, 2, 2, 2, 2 + aesthetasc, and 13; setae naked and mostly short. Antenna (Fig. 13F) massive. Articulation between coxa and basis incomplete. Exopod small, 10 × 6 μm, with three setae. First endopodal segment unarmed but with large tubercle on inner side. Second endopodal segment (Fig. 13G) 31 × 21 μm, with two blunt spiniform setae (one on inner margin and the other on distal margin) and two robust spines tipped with bundle of spinules.</p> <p>Oral cone short, stout. Mandible (Fig. 13H) with more than ten teeth distally and hyaline lamella subdistally. Maxillule (Fig. 13I) with both lobes bearing nearly parallel lateral margins; inner lobe with three setae; outer lobe subequal in length to inner lobe, with three setae; setae of outer lobe distinctly longer than those of inner lobe. Maxilla (Fig. 13J) with broad, unarmed syncoxa; basis hook-like, with fine spinules near middle; seta arising between segments naked and much shorter than basis. Maxilliped (Fig. 13K) 4-segmented; seta on syncoxa and basis small; endopod 2-segmented, but proximal segment subdivided by rudimentary articulation; proximal segment with two small setae; distal segment about 28 μm long, distally with one large seta; terminal claw 93 μm long, smooth, with denticle subdistally.</p> <p>Legs 1–3 (Fig. 14A–C) with 3-segmented rami. Leg 4 (Fig. 14D) with 3-segmented exopod and 2-segmented endopod. All of these legs lacking inner coxal seta. Basis of leg 1 with mammillary process (indicated by arrowhead in Fig. 14A) at inner distal corner and thin, needle-shaped seta near base of endopod. Leg 4 with first exopodal segment bearing almost naked inner seta; third exopodal segment armed with three spines and four setae; first endopodal segment small, 26 × 23 μm; second endopodal segment 87 × 37 μm, much broader than first segment, with slightly undulating outer margin and terminal spine of 63 μm long. Armature formula of legs 1–4 as follows:</p> <p>Coxa Basis Exopod Endopod</p> <p>Leg 1: 0-0 1-1 I-1; I-1; III, 2, 2 0-1; 0-2; 1, 2, 3</p> <p>Leg 2: 0-0 1-0 I-1; I-1; III, I, 4 0-1; 0-2; 1, 2, 3</p> <p>Leg 3: 0-0 1-0 I-1; I-1; III, I, 5 0-1; 0-2; 1, I, 3</p> <p>Leg 4: 0-0 1-0 I-1; I-1; II, I, 4 0-0; 0, I, 1</p> <p>Leg 5 (Fig. 14E) 1-segmented, clearly articulated from somite, 77 × 54 μm, 1.43 times as long as wide, with four naked setae, innermost one of them thin. Leg 6 not seen in genital aperture (Fig. 13B).</p> <p> <b>Male.</b> Body (Fig. 15A) markedly smaller than that of female, 776 μm long. Prosome 465 × 375 μm. Cephalo- thorax 306 μm long, frontally truncate. Urosome (Fig. 15B) 6-segmented. Fifth pedigerous somite 95 μm wide, with angular lateral apices. Genital somite 79×138 μm, much wider than long, with rounded corners. Four abdominal somites 50 × 98, 45 × 86, 28 × 72, and 33 × 72 μm, respectively, with convex lateral margins. Anal somite with several minute spinules on ventral surface near base of caudal rami (Fig. 15C). Caudal ramus (Fig. 15C) 50 × 30 μm, 1.67 times as long as wide; ventrodistal apex bilobed.</p> <p> <b>FIG. 13.</b> <i>Stygiopontius horridus</i> n. sp., female. A, habitus, dorsal; B, urosome, dorsal; C, anal somite and caudal rami, dorsal; D, egg sac; E, antennule; F, antenna; G, terminal segment of antenna; H, mandible; I, maxillule; J, maxilla; K, maxilliped. Scale bars: A, D = 0.2 mm; B = 0.1 mm; C, E, K = 0.05 mm; F–J = 0.02 mm.</p> <p> <b>FIG. 14.</b> <i>Stygiopontius horridus</i> n. sp., female. A, leg 1; B, leg 2; C, leg 3; D, leg 4; E, leg 5. Scale bars: 0.05 mm. <b>FIG. 15.</b> <i>Stygiopontius horridus</i> n. sp., male. A, habitus, dorsal; B, urosome, ventral; C, caudal rami, ventral; D, antennule; E, coxa, basis and endopod of leg 1; F, leg 5. Scale bars: A = 0.1 mm; B, E = 0.05 mm; C, D, F = 0.02 mm.</p> <p>Rostrum absent. Antennule (Fig. 15D) stout, strongly recurved, and 13-segmented; armature formula 1, 2, 12, 1, 4, spine+1, 1, 4, 2, 2, 2, 1+aesthetasc, and 12; fifth segment with about three vestiges of articulations on posterior side; sixth segment with outgrowth bearing two spiniform processes, its terminal spine with small warts on all surfaces and tipped with short seta; eighth segment with two blunt processes on anterior margin, each tipped with seta; eleventh and twelfth segments respectively with two and three distally-directed processes on anterior margin. Antenna as in female.</p> <p> <b>FIG. 16.</b> <i>Stygiopontius horridus</i> n. sp., copepodid I. A, habitus, dorsal; B, urosome, ventral C, antennule; D, antenna; E, mandible; F, maxillule; G, maxilla; H, maxilliped; I, leg 1; J, leg 2. Scale bars: A = 0.1 mm; B, I, J = 0.05 mm; C, D, G, H = 0.02 mm; E, F = 0.01 mm.</p> <p>Oral cone, mandible, maxillule, maxilla, and maxilliped as female.</p> <p>Leg 1 with first endopodal segment covered with numerous spinules on outer surface (Fig. 15E). Legs 2–4 as in female.</p> <p>Leg 5 (Fig. 15F) 2-segmented, but protopod short and not articulated from somite, with long outer seta; exopod 27 × 25 μm, with three setae on outer margin (middle one longer than other two) and two spiniform, blunt setae on distal margin; latter two distal setae sclerotized in proximal two-thirds and lamellate in distal third. Leg 6 represented by two unequal setae on genital operculum (Fig. 15B).</p> <p> <b>Copepodid I.</b> Body (Fig. 16A) 5-segmented, 422 μm long. Prosome consisting of cephalothorax and second pedigerous somite. Cephalothorax 213 × 193 μm, gradually narrowing posteriorly. Urosome (Fig. 16B) 3-seg- mented; first urosomite being third pedigerous somite. Second urosomite 30 × 57 μm, broadening posteriorly, with angular posterolateral corners. Anal somite 50 × 53 μm, with convex lateral margins. Caudal ramus 32 × 20 μm, with six setae; longest inner distal seta bipinnate; second longest outer distal seta pinnate along inner margin and finely spinulose along outer margin.</p> <p>Rostrum absent. Antennule (Fig. 16C) 3-segmented; second segment short; armature formula 3, 1, and 11 + 2 aesthetascs. Antenna (Fig. 16D) stout. Syncoxa and basis smooth. Exopod with two distal setae. Endopod 2-segmented; first segment unarmed; second segment with two setae and two broad, spiniform elements, one of latters with spinules at distal region.</p> <p>Oral cone short. Mandible (Fig. 16E) denticulate distally, with hyaline lamella at distal three-fourths. Maxillule (Fig. 16F) bilobed; outer and inner lobes with three and two setae, respectively. Maxilla (Fig. 16G) basically as in adult. Maxilliped (Fig. 16H) 4-segmented; syncoxa and basis unarmed; first and second endopodal segments each with one seta; terminal claw with spinules at distal region.</p> <p>Leg 1 (Fig. 16I) and leg 2 (Fig. 16J) biramous, both rami 1-segmented and lacking inner coxal seta. Basis of leg 1 with spinules along inner distal margin. Armature formula of these two legs as follows:</p> <p>Coxa Basis Exopod Endopod</p> <p>Leg 1: 0-0 1-0 IV, I, 3 1, 2, 4</p> <p>Leg 2: 0-0 1-0 III, I, 3 1, 2, 3</p> <p>Leg 3 (Fig. 16B) bilobed; outer lobe (exopod) with two setae; inner lobe unarmed. Legs 3–6 absent.</p> <p> <b>Etymology.</b> The specific name <i>horridus</i>, from Latin <i>horrid</i> (prickly), alludes to the prickly tip of the distal spines of the antenna.</p> <p> <b>Remarks.</b> <i>Stygiopontius horridus</i> n. sp. possesses the characteristic antenna and maxillule, typifying the new species. The antenna has a large tubercle on the first endopodal segment and two spinule-tipped distal spines on the second endopodal segment. The maxillule has only three (not four) setae on the inner lobe. Because these features are not shared by its congeners, the new species is easily distinguishable from other species in the genus.</p> <p>Ivanenko (1998) recorded copepodid I of a dirivultid copepod found in plankton over a hydrothermal vent on the Mid-Atlantic Ridge. This copepodid I appears to be different from our specimen from the Indian Ocean mainly in body length (0.37 mm in Ivanenko’s specimens), antennular segmentation (4-segmented in Ivanenko’s specimens) and setation, and the morphological features of the antenna (three setae on the exopod and an elongate terminal spine on the second endopodal segment in Ivanenko’s specimens).</p> <p>The discovery of a copepodid I juvenile in amplexus with a male adult in the vent community implies that copepodid I of this species stays on the bottom of the vent field and that mate guarding may take place as early as the female copepodid I stage.</p>Published as part of <i>Lee, Jimin, Kim, Dongsung & Kim, Il-Hoi, 2020, Copepoda (Siphonostomatoida: Dirivultidae) from Hydrothermal Vent Fields on the Central Indian Ridge, Indian Ocean, pp. 301-337 in Zootaxa 4759 (3)</i> on pages 320-326, DOI: 10.11646/zootaxa.4759.3.1, <a href="http://zenodo.org/record/3741134">http://zenodo.org/record/3741134</a>
Determination of the band parameters of bulk 2H-MX2 (M = Mo, W; X = S, Se) by angle-resolved photoemission spectroscopy
No full textMonolayer MX2 (M = Mo, W; X = S, Se) has recently been drawn much attention due to their application possibility as well as the novel valley physics. On the other hand, it is also important to understand the electronic structures of bulk MX2 for material applications since it is very challenging to grow large size uniform and sustainable monolayer MX2. We performed angle-resolved photoemission spectroscopy and tight binding calculations to investigate the electronic structures of bulk 2H-MX2. We could extract all the important electronic band parameters for bulk 2H-MX2, including the band gap, direct band gap size at K (-K) point and spin splitting size. Upon comparing the parameters for bulk 2H-MX2 (our work) with mono- and multi-layer MX2 (published), we found that stacked layers, substrates for thin films, and carrier concentration significantly affect the parameters, especially the band gap size. The origin of such effect is discussed in terms of the screening effect. © The Author(s) 20161341sciescopu
Expression of the fibrillin gene family in the development, differentiation and maintenance of mesenchyme cell types
No full textConnective tissue initially arises from embryonic mesenchymal stem cells (MSC) that
originate from the mesoderm during embryogenesis and are capable of differentiating
into connective tissue lineages such as adipocytes, osteoblasts, chondrocytes and
fibroblasts. Connective tissue is composed of cells held together by the extracellular
matrix (ECM). The fibrillins and latent transforming growth factor binding proteins form
a superfamily of ECM proteins characterised by the presence of a unique domain, the 8-
cysteine transforming growth factor beta binding domain (TGFß). The fibrillin proteins
(fibrillin-1, fibrillin-2 and fibrillin-3 in most vertebrates, encoded by the FBN1, FBN2
and FBN3 genes respectively), are major components of the 10nM microfibrils found in
ECM of many tissue types, for example mesenchyme-derived connective tissues.
Fibrillin-1 and fibrillin-2 are also thought to be required for stabilization and storage of
latent TGFβ complexes. Mutations in FBN1 cause Marfan syndrome, a connective tissue
disorder characterised by abnormalities in the microfibrils resulting in musculoskeletal,
ocular, cardiovascular and other complications. FBN2 mutations lead to congenital
contractural arachnodactyly, which has a musculoskeletal phenotype similar to Marfan
syndrome. There are currently no known diseases associated with FBN3 mutations.
In this project, the expression of fibrillins was investigated using human cell lines during
early development, mesenchymal stem cell differentiation and in further differentiated
mesenchymal cell lines, for example in osteocytes (osteosarcomas), chondrocytes and
fibroblast lineage. Immunocytochemistry was used to examine protein expression, real-time
PCR and expression microarrays to determine mRNA synthesis and RNAi
suppression of gene expression to determine possible functions of fibrillins and
associated ECM proteins. In addition, a genome wide bioinformatics evaluation was
performed of transcription start sites for the fibrillin gene family utilising the information
obtained from the FANTOM5 consortium.
The three fibrillin genes showed differing expression patterns in cell lines depending on
the stage of development/differentiation. During embryogenesis, expression of FBN3,
FBN2 and FBN1 increased sequentially in that order. Expression of FBN3 followed the
same pattern as expression of known pluripotency markers, while expression of FBN2
correlated with expression of markers for later stages of mesoderm differentiation. FBN1
expression was associated with mesenchymal markers, and this was supported by a study
of mesenchymal stem cells differentiation to the adipose lineage. Fibrillin-1 microfibrils
and RNA expression were present early in primary adult human MSC differentiating to
adipocytes, suggesting that a fibrillin matrix is required for initial MSC attachment. As
differentiation proceeded, fibrillin -1 expression decreased, with rapid degradation of the
microfibrils. Fibrillin-2 expression increased following differentiation and fibrillin-3 was
not expressed. These results suggest that fibrillin-1 plays an important structural and
regulatory role in the early stages of connective tissue development but is not required to
maintain the differentiated state.
Many genes showed the same expression pattern as FBN1. To better understand the
importance of fibrillin-1 and its interaction with these coexpressing genes, fibrillin-1 was
knocked down using siRNA in fibroblast, chondrocyte and osteosarcoma cell lines. There
were little to no effects identified in chondrocyte and osteosarcoma cell lines, and only a
few genes were altered following the reduction of fibrillin-1 mRNA in fibroblasts,
suggesting that fibrillin-1 is not a central regulator but an endpoint. This was surprising
given its potential role in controlling bioavailability of TGFβ, a key regulator of
mesenchymal cells.
In addition, the evolution of the fibrillin gene family was studied and it was found that
the gene structure, amino acid sequence and genomic positions of each gene are widely
conserved across vertebrates, suggesting an important role in vertebrate body structure.
However, the differences in gene structure and sequence between the three fibrillin genes
suggest divergent function. Fibrillin-1 mutations with the most severe phenotypes are
located in regions that are highly conserved. This study shows that there is a clear
developmental and evolutionary distinction between the three fibrillins. Fibrillin-3 was
associated with pluripotency and its presence in differentiating foetal liver and brain may
suggest that there are residual pluripotent cells in these developing tissues. Fibrillin-2
appeared to be a marker for the mesodermal stage and its role in adult cells is currently
not clear. Fibrillin-1 was present in cells already predetermined to go to mesenchymal
lineages, but it was minimal in the advanced stages of differentiation suggesting that it
may be a marker for relatively plastic mesenchymal cells prior to commitment to a
specific lineage.
These results will assist in the understanding of disorders resulting from fibrillin gene
mutations and have identified coexpressed proteins, potential modifiers that could be the
targets of gene therapy and candidates for similar connective tissue
The magic of storytelling : learning the craft at Millward Brown.
No full textThis report documents the learning journey of an intern at Millward Brown, one of the world’s top ten research agencies. As part of the curriculum structure, third year Communication Studies students at Wee Kim Wee School of Communication and Information are required to undergo a 24-week Professional Internship (PI) at an organization. The author chose to work at Millward Brown so that he could immerse himself in the market research sector and had a taste of what the future working life as a market researcher is like.
Throughout the report, bits and pieces of experience of the author as an intern will be weaved together to provide a snapshot of the vibrancy of the market research sector through the lenses of Millward Brown.
This report, hence, seeks to give an insight into the internal structure of Millward Brown, the services it provides as well as its relationship with clients and its position in the research sector. In addition, this report also outlines the training and the knowledge that the author has acquired as an intern research associate as well as how he has applied this training in his daily jobscope with four different clients: Johnson & Johnson, Pepsi Co., Cerebros, and Gillette.
Above all, facets of the working life, working environment, and other social skills required at work are also reflected on in this report. The author concludes the report with the major takeaways he has from 24 weeks of hands-on learning that will in one way or another provide him with a better picture of the working world that he might join one day.COMMUNICATION STUDIE
Stygiopontius spinifer Lee & Kim & Kim 2020, n. sp.
No full textStygiopontius spinifer n. sp. (Figs 11, 12) http://zoobank.org/ BBD02F2A-B2ED-4EEF-A084-EACA8134C4BE Material examined. Fifty-five females from sediments at GTV 1809 (11°24.883´S, 65°25.425´E, depth 2022 m), the Onnuri vent field on the Central Indian Ridge, 23 June 2018. Holotype (female, MABIK CR00244729) and paratypes (30 females, MABIK CR00244730) have been deposited in the Marine Biodiversity Institute of Korea (MABIK), Seocheon. Other specimens are retained in the collection of the junior author. Additional material examined. Ten females (one female dissected) from washings of invertebrates at GTV 1702 (19°33.387´S, 65°50.893´E, depth 2507 m), the Solitaire vent field on the Central Indian Ridge, 01 August 2017; four females from washings of invertebrates at GTV1807 (19°33.395´S, 65°50.889´E, depth 2634 m), the Solitaire vent field on the Central Indian Ridge, 20 June 2018. Female. Body (Fig. 11A) dorsoventrally flattened, 1.51 mm long. Prosome 865 × 742 μm, oviform in dorsal view; posterolateral corners pointed in cephalothorax and second pedigerous somite, but rounded in third and fourth pedigerous somites. Cephalothorax 523 μm long. Urosome (Fig. 11B) 5-segmented. Fifth pedigerous somite trap- ezoidal, 199 μm wide, with blunt lateral apices. Genital double-somite 184 × 180 μm; anterior third broader than posterior two thirds, with claw-like, posteriorly directed lateral process on both sides near genital aperture; narrower posterior part gradually narrowing posteriorly. Three free abdominal somites 85 × 119, 61 × 109, and 61 × 107 μm, respectively. Anal somite with five or six spinules along both sides of posteroventral border (Fig. 11C). Caudal rami (Fig. 11C) parallel; each ramus 97 × 45 μm measured in ventral view, 2.16 times as long as wide, with six setae (setae II–VII); two larger mid-terminal setae pinnate along distal two thirds; inner terminal seta unilaterally pinnate along inner margin; other three setae naked. Rostrum absent.Antennule (Fig. 11D) 430 μm long and 12-segmented; third segment longest; armature formula FIG. 11. Stygiopontius spinifer n. sp., female. A, habitus, dorsal; B, urosome, dorsal, C, caudal rami, ventral; D, antennule; E, antenna; F, mandible; G, maxillule; H, maxilla; I, maxilliped. Scale bars: A = 0.2 mm; B = 0.1 mm; C–I = 0.05 mm. FIG. 12. Stygiopontius spinifer n. sp., female. A, leg 1; B, leg 2; C, leg 3; D, leg 4; E, leg 5; F, left genital aperture. Scale bars: 0.05 mm. 1, 2, 12, 8, 2, 4, 2, 2, 2, 2, 2 + aesthetasc, and 13; aesthetasc on penultimate segment more than twice as long as terminal segment; setae generally short, all of them naked. Antenna (Fig. 11E) with short, unarmed syncoxa. Basis smooth. Exopod small, 13 × 9 μm, with three setae. Endopod 2-segmented; proximal segment 62 × 29 μm, with fine spinules along distal half of outer margin; distal segment 43 × 21 μm, with two spines, two setae, and few setules. Oral cone stout. Mandible (Fig. 11F) with about ten teeth distally, one blunt process near distal fourth of outer margin, and two hyaline lamellae (proximal and distal) on inner margin. Maxillule (Fig. 11G) bilobed; outer lobe with four setae, including three large, weakly pinnate and one small, naked ones; inner lobe with four setae distally and several setules on inner margin. Maxilla (Fig. 11H) as usual in the genus; seta between segments not extending over basis. Maxilliped (Fig. 11I) 5-segmented; syncoxa and basis each with one inner seta, 54 and 45 μm long, respectively, both spinulose in distal half; endopod with two, two, and one setae, respectively, on first to third segments; third segment 45 μm long; terminal claw 117 μm long, weakly arched, with spinules along distal half of inner margin. Legs 1–4 (Fig. 12A–D) without inner seta on coxa. Second endopodal segment of legs 1–3 with bicuspid outer distal corner. Inner distal spine on basis of first leg 40 μm long and slender. Basis of leg 2 with five spinules on inner side. Leg 4 (Fig. 12D) with three spines and four setae on third exopodal segment; first endopodal segment 45 × 26 μm; second endopodal segment 76 × 32 μm, its distal spine 100 μm long. Armature formula of legs 1–4 as follows: Coxa Basis Exopod Endopod Leg 1: 0-0 1-I I-1; I-1; III, 2, 2 0-1; 0-2; 1, 2, 3 Leg 2: 0-0 1-0 I-1; I-1; III, I, 4 0-1; 0-2; 1, 2, 3 Leg 3: 0-0 1-0 I-1; I-1; III, I, 5 0-1; 0-2; 1, I, 3 Leg 4: 0-0 1-0 I-1; I-1; II, I, 4 0-0; 0, I, 1 Leg 5 (Fig. 12E) unsegmented but divided into proximal and distal parts by unsclerotized band on both surfaces; proximal part 46 × 32 μm, with large, feebly pinnate seta; distal part 23 × 23 μm, with three setae, larger outer seta twice as long as two smaller inner setae. Leg 6 (Fig. 12F) represented by one naked seta in genital aperture. Male. Unknown. Etymology. The specific name spinifer, Latin spin (=a spine) and fero (=to carry), alludes to the spiniform process on the lateral margins of the genital double-somite, as in several congeners. Remarks. The genus Stygiopontius is characterized by the combination of the features, as follows: (1) the endopod of leg 1 is three-segmented in both sexes; (2) the first endopodal segment of leg 3 is armed with an inner seta; (3) the first endopodal segment of leg 4 lacks an inner seta; and (4) the second endopodal segment of leg 4 is armed with one distal spine and one inner seta. In the genus Stygiopontius, seven species are known to have, like S. spinifer n. sp., two (not three) outer spines on the third exopodal segment of leg 4 (armature formula II, I, 4), as follows: S. cinctiger Humes, 1987, S. lomonosovi Ivanenko and Martinez Arbizu 2006, S. mucroniferus Humes, 1987, S. rimivagus Humes, 1997, S. serratus Humes, 1996, S. teres Humes, 1996, and S. verruculatus Humes, 1987. In six of these species, at least one of legs 1–4 has an inner seta on the coxa. In S. verruculatus, the remaining species, there is no inner seta on the coxa of any of legs 1–4, which is comparable with S. spinifer n. sp. Stygiopontius verruculatus, known from the East Pacific Rise, was described based only on the male (Humes 1987). Although a direct comparison between it and S. spinifer n. sp. may be difficult, some sexually non-dimorphic characters may be used to compare male S. verruculatus and female S. spinifer n. sp., as follows: (1) the epimeral regions of the fourth pedigerous somite are rounded in S. spinifer n. sp. but tapering and pointed in S. verruculatus; (2) the innermost distal seta on the caudal ramus of S. spinifer n. sp. is unilaterally pinnate, whereas that of S. verruculatus is naked; and (3) the inner element on the basis of the maxilliped is a seta located at the proximal third in S. spinifer n. sp. but a ball-like process located near distal third in S. verruculatus.Published as part of Lee, Jimin, Kim, Dongsung & Kim, Il-Hoi, 2020, Copepoda (Siphonostomatoida: Dirivultidae) from Hydrothermal Vent Fields on the Central Indian Ridge, Indian Ocean, pp. 301-337 in Zootaxa 4759 (3) on pages 317-320, DOI: 10.11646/zootaxa.4759.3.1, http://zenodo.org/record/374113
Benthoxynus constrictus Lee & Kim & Kim 2020, n. sp.
No full textBenthoxynus constrictus n. sp. (Figs 9, 10) http://zoobank.org/ 13B0DBCD-6362-49E6-BE95-0509CBCB4863 Material examined. Two females from washings of invertebrates at GTV1702 (19°33.387´S, 65°50.893´E, depth 2507 m), the Solitaire vent field on the Central Indian Ridge, 01 August 2017. Holotype (female, MABIK CR00244728) has been deposited in the Marine Biodiversity Institute of Korea (MABIK), Seocheon. Dissected paratype is retained in the collection of the junior author. Female. Body (Fig. 9A) narrow, 1.78 mm long. Prosome oviform, 930 × 750 μm. Cephalothorax 632 μm long, with tapering posterolateral corners. Second to fourth pedigerous somites with rounded posterolateral corners. Urosome (Fig. 9B) slender. Fifth pedigerous somite laterally constricted in middle, with dorsal posterolateral extensions. Genital double-somite rhomboidal, 222 × 236 μm, widest at proximal third; genital aperture located dorsolaterally slightly posterior to widest region. Three free abdominal somites 139 × 113, 90 × 100, and 90 × 102 μm, respectively. Abdominal somite and caudal rami smooth, without setules or spinules on all surfaces. Caudal rami (Fig. 9C) slightly divergent; each ramus 209 × 43 μm, 4.86 times as long as wide, armed with six setae (setae II–VII); dorsal seta located subdistally and other five setae on distal margin; two larger mid-terminal setae weakly pinnate along distal half; inner distal seta characteristically small, obscure. Rostrum absent. Antennule (Fig. 9D) 710 μm long and 12-segmented; third segment longest, with five trans- verse sclerotization bands on one surface (not shown in Fig. 9D); armature formula 1, 2, 12, 10, 2, 4, 2, 2, 2, 2, 2 + aesthetasc, and 13; aesthetasc on penultimate segment slender, slightly longer than terminal segment. Antenna (Fig. 9E) with short, unarmed syncoxa. Basis smooth. Exopod small, 19 × 9 μm, with three setae distally. Endopod 2-segmented; proximal segment 98 × 43 μm, unarmed; distal segment 72 × 35 μm, with four setae (one small inner, two subdistal, and one large distal) and several setules near base of outer subdistal seta. Oral cone stout as usual in the family. Mandible (Fig. 9F) as flattened stylet, with more than ten teeth distally and hyaline lamella along distal fourth of inner margin. Maxillule (Fig. 9G) bilobed; outer lobe with four setae (three distal and one subdistal); inner lobe with strongly protruded inner margin and four distal setae; both outer and inner lobes smooth without setules or spinules. Maxilla (Fig. 9H) 2-segmented; syncoxa unarmed, with pore at basal region; basis elongate, with fine spinules and setules at distal region, one of setules large; one large seta present, arising between syncoxa and basis. Maxilliped (Fig. 9I) 5-segmented; syncoxa with one inner distal seta of 42 μm long; basis with inner seta of 71 μm long; endopod 3-segmented, with two, one, and one setae, respectively; two setae on first endopodal segment minute, obscure; third endopodal segment 52 μm; terminal claw 174 μm long, weakly arched, with spinules along distal half of inner margin. Legs 1–4 (Figs. 10A–D) lacking inner coxal seta; outer seta on basis thin and naked; setae of these legs, especially those of endopod, swollen in proximal third and weakly pinnate in distal half. Second exopodal segment of leg 1 small, with outer spine and inner seta; all of other elements on leg 1 setiform. Inner distal seta on basis of leg 1 minute, needle-like. First endopodal segment of leg 3 unarmed, lacking inner seta. First and second endopodal FIG. 9. Benthoxynus constrictus n. sp., female. A, habitus, dorsal; B, urosome, dorsal C, caudal rami, dorsal; D, antennule; E, antenna; F, mandible; G, maxillule; H, maxilla; I, maxilliped. Scale bars: A = 0.5 mm; B, D, E = 0.1 mm; C, F–I = 0.05 mm. FIG. 10. Benthoxynus constrictus n. sp., female. A, leg 1; B, leg 2; C, leg 3; D, leg 4; E, leg 5; F, right genital aperture. Scale bars: A–D = 0.1 mm; E = 0.02 mm; F = 0.05 mm. segments of leg 4 smooth, 86 × 41 and 133 × 35 μm, respectively; terminal seta 145 μm long. Armature formula of legs 1–4 as follows: Coxa Basis Exopod Endopod Leg 1: 0-0 1-1 1-1; 1-1; 3, 1, 3 0-1; 0-2; 1, 2, 3 Leg 2: 0-0 1-0 I-1; I-1; III, I, 4 0-1; 0-2; 1, 2, 3 Leg 3: 0-0 1-0 I-1; I-1; III, I, 5 0-0; 0-2; 1, I, 3 Leg 4: 0-0 1-0 I-1; I-1; III, I, 4 0-0; 0, I, 0 Leg 5 (Fig. 10E) 1-segmented, clearly articulated from somite, 45 × 23 μm, about twice as long as wide, with three naked setae (one dorsal and two distal). Leg 6 absent (Fig. 10F). Male. Unknown. Etymology. The specific name constrictus refers to the lateral constriction of the fifth pedigerous somite. Remarks. Benthoxynus spiculifer Humes, 1984 and B. tumidiseta Humes, 1989, the two known members of the genus, were recorded from hydrothermal vent fields in the East Pacific. These two congeners of B. constrictus n. sp. have the following features which are useful for differentiating them from the new species: (1) Leg 5 is lobate, unarticulated from the fifth pedigerous somite (vs. free in B. constrictus n. sp.). (2) The antennule is 18-segmented in B. spiculifer and 11-segmented in B. tumidiseta (vs. 12-segmented in B. constrictus n. sp.) (3) The caudal ramus is longer than that of n. sp., 240 μm in B. spiculifer and 313 μm in B. tumidiseta (Humes, 1984, 1989) (vs. 209 μm in B. constrictus n. sp.), although their bodies are smaller than that of B. constrictus n. sp. (recorded as 1.68 and 1.67 mm long, respectively, in their original descriptions). (4) The fifth pedigerous somite is not constricted laterally (vs. strongly constricted in B. constrictus n. sp.). Genus Stygiopontius Humes, 1987Published as part of Lee, Jimin, Kim, Dongsung & Kim, Il-Hoi, 2020, Copepoda (Siphonostomatoida: Dirivultidae) from Hydrothermal Vent Fields on the Central Indian Ridge, Indian Ocean, pp. 301-337 in Zootaxa 4759 (3) on pages 314-317, DOI: 10.11646/zootaxa.4759.3.1, http://zenodo.org/record/374113
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