• Title/Summary/Keyword: Retina structure

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Fine Structural Analysis of Principal and Secondary Eyes in Wandering Spider, Pardosa astrigera (배회성 거미 (Pardosa astrigera) 주안과 부안의 미세구조적 분석)

  • Jeong, Moon-Jin;Lim, Do-Seon;Moon, Myung-Jin
    • Applied Microscopy
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    • v.30 no.1
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    • pp.1-9
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    • 2000
  • The wandering spider, Pardosa astrigera, had four pairs of ocelli that arranged in three rows on the cephalothorax. Along the anterior margin lay a pair of small anterior median (AM) eye flanked on each side by anterior lateral (AL) eye. Two large posterior median (PM) eye was situated on the clypeus behind the anterior row and still more posteriorly was a pair of posterior lateral (PL) eye. The visual cell of retina consisted of cell body, rhabdome, and intermediate segment. Bipolar neuron was found in anterior median eye (principal eye) and unipolar neuron in others (secondary eye). Rhabdome showed that arranged in PMeye and PLeye. But rhabdomes of AMeye and ALeye were irregular in retina. Except AMeye, incontinuous tapetum found in ALeye, PMeye, PLeye. Anterior median eye was similar to anterior lateral eye in length and posterior median eye similar to posterior lateral eye. Component size of eye were similar to 4 pairs eye in cornea. Size of lens, cell body, and rhabdome was similar not only anterior median eye and anterior lateral eye but also posterior median eye and posterior lateral eye. Vitreous body was large posterior median eye than others.

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A Study on Pointillistic Rendering Based on User Defined Palette (사용자 정의 팔레트에 기반한 점묘화 렌더링에 관한 연구)

  • Seo, Sang-Hyun;Yoon, Kyung-Hyun
    • Journal of Korea Multimedia Society
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    • v.11 no.4
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    • pp.554-565
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    • 2008
  • The French neo-impressionist painter, George Seurat, introduced pointillism under the theory that the individual pigments of colors on the canvas are reconstructed on the human retina. Pointillism is a painting technique in which many small brush strokes are combined to form a picture in the canvas. When such a painting is seen from a far, the individual stroke color are unnoticeable and they are seen as intermixed colors. This is called juxtaposed color mixture. In this paper, we present a painterly rendering method for generating the pointillism images. For expressing countless separate dots which shown in the pointillism works, we propose a hierarchical points structure using Wang The method. Also a user defined palette is constructed based on the usage that Neo-Impressionist painter works on his palette. Lastly, based on this, a probability algorithm will be introduced, which divides the colors in the image(sampled by hierarchical point structure) into juxtaposed colors. A hierarchical points set which undergone juxtaposed color division algorithm is converted into brush strokes.

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Histological Study of Oculocutaneous Albinism in Korean Far Eastern Catfish Silurus asotus (백색증 메기 Silurus asotus에 관한 조직학적 연구)

  • Park, Jong-Young;Oh, Min-Ki;Yoon, Seung-Woon;Lee, Wan-Ok
    • Korean Journal of Ichthyology
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    • v.21 no.2
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    • pp.100-105
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    • 2009
  • Histological study of normal and albinic catfish Silurus asotus produced in aquaculture has been carried out on organs such as the eye, the barbel, the dorsal fin, and the skin (including dorsal, ventral and lateral regions). Although individuals have no differences in morphological appearance, their colors showed clear difference as follows: the normal catfishes were black overall, but the albinic ones have a yellowish-white color over the whole body, red eyes and white barbels. All the organs investigated were fundamentally very similar in structure. Regarding the distribution and density of the melanin pigments, however, the albinic catfish have no melanin in the skin and eye, particularly in the basement membrane of the epidermis and the pigment epithelial layer in the retina, while the normal catfish have lots of melanin. This phenomenon may coincide with the so-called $i^1/i^1$ type of oculocutaneous albinism.

Ultrastructure of the Eyes of Menemerus fulvus (Araneae: Salticidae) (흰수염깡충거미(Menemerus fulvus) (거미목, 깡충거미과)시각기의 미세구조)

  • 김주필;권중균
    • The Korean Journal of Soil Zoology
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    • v.5 no.2
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    • pp.101-112
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    • 2000
  • Spiders usually have poor vision but not the jumping spiders. Their eight eyes are located on its distinctive box-shaped head and relatively well developed. The Spiders were fixated with 3% glutaraldehyde and thin section was performed with ultra-microtome. The specimens were observed with light microscopy, transmission and scanning electron microscopy. Eye area of jumping spider is competed of three rows. The first eye row comprise four eyes. Among them, two anterior median eyes are the largest and two anterior lateral eyes are relatively small. The former are main-eyes and have excellent vision. The second row, which has the two smallest eyes, is located about midway between the first and third rows. The third row is about half-way back on the thorax and eyed of which are middle size. To investigate ultrastructure of salticid spiders'eye, Menemerus fulvus was chosen. All of Menemerus fuvus's eyes are composed of cornea, lens, vitreous body and retina in histologically. Cornea layer, linked to exocuticle of exoskeleton. is regular layer structure without any cell tripe. Lenses are biconvex type. Retinas comprise well developed microvilli-shape rhabdomeres, unpigmented supporting cells, and pigmented cell. Retinas of anterior median eyes are surrounded by circular cylinder-shaped vitreous body, photoreceptor, i.e. rhabdomeres, of it is irregularly arranged compared to the other eyes.

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