• Title/Summary/Keyword: morphological variations

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Polymorphic stages of the fresh water blue-green alga, Gomphosphaeria aponina

  • Dwivedi, V.K.;Tandon, Richa;Tiwari, G.L.
    • ALGAE
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    • v.25 no.3
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    • pp.115-120
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    • 2010
  • The natural growth of a population of Gomphosphaeria aponina Kutzing (Chroococcales, Cyanoprocaryota) was studied in a cemented freshwater tank in Allahabad, India. This population appeared to be a polymorphic species. Different species of the genus Gomphosphaeria have been segregated based on morphological features of colonies, cells and mucilage. However, these features are not well defined for different species. Our observations revealed many feature variations and, interestingly, certain features that have been described for different Gomphosphaeria species were seen in a single population. In this study, records of such variable morphological features were possible due to the availability of numerous specimens and continuous observations for more than two years. Further, this study revealed two points: (i) more detailed morphological studies are required both from nature as well as in culture to identify critical differences among the species, and (ii) molecular characterization of taxa appears to be necessary for final species settlement.

Morphological Variation of Lingulodinium polyedrum (Dinophyceae) in Culture Specimens and Reinterpretation of the Thecal Formula

  • Kim, Keun-Yong;Yoshida, Makoto;Kim, Chang-Hoon
    • ALGAE
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    • v.20 no.4
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    • pp.299-304
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    • 2005
  • Morphological observation of a unialgal culture of Lingulodinium polyedrum was conducted under light- and scanning electron microscopes. Lingulodinium polyedrum was redefined as having the thecal formula of APC, Q, 5', 6", 6c, 6s, 5'", 2"" using the reinterpreted tabulation system. In our tabulation system, the Q, which is equivalent to the 3' in the strict Kofoidean system, was treated as an auxiliary platelet because of its considerable morphological variations in culture specimens. Subsequently, apical plates were redefined as plates directly connected to the APC and/or the Q. The 1"' and the 1p in the conventional Kofoidean system were treated as a component of the sulcus (the Ssa) and as an antapical plate (the 1""), respectively. Our reinterpreted tabulation system clearly differentiated extant gonyaulacalean taxa.

Effects of Hemodynamics on Morphological Changes of Human Endothelial Cells (혈액유동이 혈관내피세포의 형태변화에 미치는 영향)

  • Suh, Sang-Ho;Yoo, Sang-Sin;Min, Byung-Gu;Chang, Jun-Keun
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.22 no.11
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    • pp.1521-1529
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    • 1998
  • The objective of this study is to investigate the effects of the hemodynamics on the morphological changes of the human endothelial cells due to the blood flow by in vitro experiment and computer simulation. The morphological changes of the endothelial cells due to the t10w shear stress were observed in the laminar t10w chamber as a function of the exposure time. The observed shapes of the endothelial cells are used to the model shapes of the endothelial cells for numerical study and the pressure and the wall shear stress variations around the endothelial cells are calculated from the numerical results. The endothelial cells elongate along the t10w direction and lessen their heights in the flow field to reduce the pressure and the wall shear stress on the surface.

Modeling Cross-morpheme Pronunciation Variations for Korean Large Vocabulary Continuous Speech Recognition (한국어 연속음성인식 시스템 구현을 위한 형태소 단위의 발음 변화 모델링)

  • Chung Minhwa;Lee Kyong-Nim
    • MALSORI
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    • no.49
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    • pp.107-121
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    • 2004
  • In this paper, we describe a cross-morpheme pronunciation variation model which is especially useful for constructing morpheme-based pronunciation lexicon to improve the performance of a Korean LVCSR. There are a lot of pronunciation variations occurring at morpheme boundaries in continuous speech. Since phonemic context together with morphological category and morpheme boundary information affect Korean pronunciation variations, we have distinguished phonological rules that can be applied to phonemes in within-morpheme and cross-morpheme. The results of 33K-morpheme Korean CSR experiments show that an absolute reduction of 1.45% in WER from the baseline performance of 18.42% WER was achieved by modeling proposed pronunciation variations with a possible multiple context-dependent pronunciation lexicon.

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Morphological Variation and Characteristics of Native Medium-Leaf Type Zoysiagrasses (Zoysia spp.) by Site Environment (입지환경에 따른 자생 중엽형 한국잔디의 형태적 변이 및 특성)

  • Bae, Eun-Ji;Lee, Kwang-Soo;Han, Eun-Hui;Park, Yong-Bae;Lee, Sang-Myeong;Huh, Moo-Ryong
    • Weed & Turfgrass Science
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    • v.2 no.2
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    • pp.184-190
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    • 2013
  • It is important for genetic resources to collect and identify in native medium-leaf type zoysiagrasses species distributed in Korea. This study was conducted to investigate morphological variation and characteristics of native medium-leaf type zoysiagrasses from coastal, island and inland regions in Korea. Among them, 75 collected lines was confirmed to have various morphological variations, accessions were classified into 2 main based group coastal and inland regions by morphological characteristics and site environment. Group I included Z. sinica type, this group showed 3.7 mm in leaf width, 29 in number of seed per spikelet and 5.0 mm in seed length. Group II included Z. japonica type, this group showed 4.4 mm in leaf width, 42 in number of seed per spikelet and 3.5 mm in seed length. There is a need for additional research on growth characteristics and the molecular level for the introgressive hybridization between species which confirmed that cross-pollination is possible due to protogyny. The individuals showing variations should be preserved as valuable genetic resources for the expansion of variations in zoysiagrasses, and the results of this investigation on the genetic resources collected will be highly valuable in breeding high quality turfgrass.

Morphological and Genetic Characteristics of Pearl-spot Damselfish Chromis notata (Teleostei: Pomacentridae) in Coastal Waters of East Sea (Sea of Japan) and Jejudo (제주도와 동해 근해에 서식하는 자리돔(Chromis notata)의 형태와 유전특성 비교)

  • Shin, Hye Jeong;Kim, Sun Wook;Choi, Young-Ung
    • Ocean and Polar Research
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    • v.36 no.2
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    • pp.189-197
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    • 2014
  • The pearl-spot damsel, Chromis notata, is one of the important fishery species in Korea. While C. notata has been commonly harvested in southern Korea, the increasing number of C. notata in higher latitudes has crucial ecological, economic and evolutionary implications under conditions where the climate is rapidly changing. Here we examined the morphological and genetic characteristics of C. notata to assess patterns of geographical variations among the groups from three different sites. The groups were clearly distinguishable in the analysis of morphological characteristics. On the other hand, the groups were genetically indistinguishable. All individuals fell within a single clade in the neighbor-joining tree but appeared scattered in the haplotype network. Several haplotypes are shared among the sampling sites (Jejudo-Ulleungdo; Hap 9, Wangdolcho-Ulleungdo; Hap 28, Hap 33, Hap 34). Although control region markers did not elucidate the spatial patterns in genetic characteristics, Wangdolcho and Ulleungdo groups appear to exhibit a more robust gene flow between the two groups than with Jejudo group. Integrative approaches such as those combining morphological and genetic analyses minimize potential errors caused by limited perspectives of each analysis and can provide useful information for discovering functional DNA regions attributable to morphological characteristics expressions.

Modeling Cross-morpheme Pronunciation Variation for Korean LVCSR (한국어 연속음성인식을 위한 형태소 경계에서의 발음 변화 현상 모델링)

  • Lee Kyong-Nim;Chung Minhwa
    • Proceedings of the KSPS conference
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    • 2003.05a
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    • pp.75-78
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    • 2003
  • In this paper, we describe a cross-morpheme pronunciation variation model which is especially useful for constructing morpheme-based pronunciation lexicon for Korean LVCSR. There are a lot of pronunciation variations occurring at morpheme boundaries in continuous speech. Since phonemic context together with morphological category and morpheme boundary information affect Korean pronunciation variations, we have distinguished pronunciation variation rules according to the locations such as within a morpheme, across a morpheme boundary in a compound noun, across a morpheme boundary in an eojeol, and across an eojeol boundary. In 33K-morpheme Korean CSR experiment, an absolute improvement of 1.16% in WER from the baseline performance of 23.17% WER is achieved by modeling cross-morpheme pronunciation variations with a context-dependent multiple pronunciation lexicon.

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Distancing the Constraints on Syntactic Variations

  • Choi, Hye-Won
    • Language and Information
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    • v.11 no.1
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    • pp.77-96
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    • 2007
  • This paper investigates syntactic variations in English such as Dative Alternation, Particle Inversion, and Object Postposition (Heavy NP Shift) within the framework of Optimality Theory, and shows that the same set of morphological, informational, and processing constraints affect all these variations. In particular, it shows that the variants that used to be regarded as ungrammatical are in fact used fairly often in reality, especially when processing or informational conditions are met, and therefore, grammatical judgment may not be always categorical but sometimes gradient. It is argued that the notion of distance in constraint ranking in stochastic OT can effectively explain the gradience and variability of grammaticality in the variation phenomena.

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