263 research outputs found
Post-larval development in deep-sea echinoderms
No full textThe post-larval phase is an essential period in the life history of marine invertebrates; vulnerable to high mortality, it ultimately influences the distribution and abundance of adult populations. The post metamorphic ontogenesis of thirty species of deep-sea echinoderms, belonging to three classes (Ophiuroidea, Asteroidea and Echinoidea), is described using scanning electron microscopy. The life history of Ophiocten gracilis is also examined as a case study for future research on post-larval organisms. The analysis of development in ophiuroids reveals that species can be identified from a very early post metamorphic stage, even in congeneric species, contrary to the findings of other authors. The ontogeny of homologous structures is similar within related groups, but may give rise to different adult structures indifferent taxa. The mouth papillae within the ophiurids are serially homologous, originating from the jaw, but the fourth mouth papilla may have a different origin. In the families Ophiactidae, Ophiacanthidae and Amphilepididae examined, the mouth papillae have different origins, as, for instance, the adoral shieldspine or tentacle scale. Data on the post-larval development of Ophiura affinis suggest that this species is more closely related to the genus Ophiocten and a change in the generic status is proposed. Ophiocten gracilis is a bathyal brittle star occurring on both sides of the North Atlantic and its life history is studied in the eastern side of the North Atlantic. In this area, O. gracilis spawns in February/March of each year producing a large number of eggs. Fecundity is estimated to be around 40,000 eggs/ind, with the population of the Hebridean Slope being able to produce probably up to 16 million eggs/m2. Post-larvae start settling in May and numbers settling reached over 3,200 post-larvae/m2. The settling speed of post-larvae in the water column is estimated to be around 500 m/day, settling faster in warmer than colder water. Settling speeds appear to be similar for post-larvae ranging from 0.6 to 0.9 mm in disk diameter. Size at settlement is around 0.6 mm in disk diameter and 5-6 arm segments. The settlement of post-larval O. gracilis on the bottom of the Hebridean Slope also represented a considerable fraction of the particulate organic carbon (POC) flux in the area, reaching over 7% of the total daily flux. This is likely to have a considerable impact in the benthic community as competition and predation and as an additional food source for demersal and benthic organisms. The occurrence of post-larvae of O. gracilis in sediment traps also represented a large problem for POC flux measurements, with ophiuroids consuming part of the flux. In future works with sediment traps, such errors must be taken into account and ophiuroids must be included in the total POC flux. The deep-sea juvenile asteroids of the NE Atlantic could be distinguished to species level from a very early stage of development. The ontogenesis of Porcellanaster ceruleus shows that this species is likely to undergo a shift in habitat and diet during the juvenile phase. This is evidenced by the appearance of the epiproctal cone, the changing of the furrow and apical spines, the early development of the cribriform organ adjacent to the madreporite and the appearance of sediment in the stomach. P. ceruleus is probably a predator on meiofauna and small macrofaunal organisms during the early stages of life, changing to a burrowed life style ingesting sediment particles. Most juvenile sea stars analysed during the present study showed wider bathymetric distribution than their adult counterparts, suggesting that events occurring during the early stages of life are important for the maintenance of the local population structure and diversity in the deep NE Atlantic.The post-metamorphic development of three deep-sea spatangoid echinoids is very similar, but the morphology and formation of fascioles facilitate the distinction of the species examined. Whereas in Hemiaster expergitus and Spatangus raschi the fascioles present in the post-larvae develop to form the adult fascioles, in Brissopsis lyrifera post-larvae there is a juvenile fasciole, which disappears during ontogenesis giving way to the adult fascioles. The function of the juvenile fasciole is unknown in B.lyrifera. The development of the periproct in all spatangoids examined is similar to that described by other authors, with the periproct being initially endocyclic and migrating towards the rear of the animal as development progresses. Post-larvae of the genus Echinus could not be separated into different species, which may be linked to the recent diversification of the genus in the North Atlantic. The widespread settlement of echinoderm post-larvae reported in the present thesis and in other works is thought to have been very important for the colonization of the deep-sea through the supply of stages to deeper areas and selection of pressure adapted animals and subsequent speciation
Change of Landscape along the Sumida River deduced from photograph
No full textThe Sumida River flowing the central Tokyo, contributed the development of Tokyo through the modern ages. Land use, landscape and waterscape of the river have also changed. The author has assessed the landscape and waterscape since the Meiji Era using photographs, Eight elements on landscape, i.e. “natural land-use”, “urban land-use”, “from of dike”, enviroument of bank”, “plant”, “structure of dike”, “materials of dike”, “close-to-water establishment” were taken for the analysis, and marks were given for each element. The mark is qualitatine five score system in which 5 is given for complete “yes or good” and 1 is complete “no or bad”. The amalysis was made at the Shirahige, Azuma and Ryogoku Bridges, for the era of pre-1900's, 1930's, 1950's and present. The results are presented on radar chart. As the result, it may be said that the river has affected by the human activity since the beginnings of the twentieth century and changed from natural landscape to urban landscape. In 1930's, environment around the Shirahige Bridge kept the natural landscape while urban elemnts has been noted at the Azuma Bridge and Ryogoku Bridge. In 1950's, score of the assessment showed the lowest. At present, since close-to-water embankment has been constructed along the river, therefore, the score has recovered.短報SHORT ARTICLESdepartmental bulletin pape
The diameter growth–height growth relationship as related to the diameter–height relationship
No full textStable Foliage Cluster (FC), a Basic Unit of the Crown Structure of Tree Species and Its Application to Modeling of Tree and Forest Structure: Configuration of the FC Model
No full textThe "foliage cluster (FC) model" shows that the size (the amount of leaves, number of yearly shoots and total twig length), turnover time, and branching (i.e., forking) structure of a twig becomes stable in the top of the crown in an oak species by forming a "stable FC" [1]. A stable FC can be treated as a basic component of the crown structure and as an alternative to individual leaf or current-year shoot. The FC model is composed of several equations approximating the branching structure of twigs. Differences in size and branching morphology among twigs are represented by differences in values of the parameters of the equations. We described details of our analyses of data taken from real twigs and applied to the equations implemented in the FC model
Formation of a Structure of Exponentially Forking Branches with a Steady-state Amount of Current-year Shoots in a Hardwood Tree Crown
No full textForking branches are a structural pattern characterizing a tree species. For a tree species, as a sessile organism, the forking structure is essential for gaining solar energy by spreading leaves in lighter spaces as quickly as possible. The structure is an outcome of a process in which a mother shoot of a branch produces multiple daughter shoots, and thus allows a tree to exponentially increase the amount of leaves available for photosynthetic production. On the other hand, in closed hardwood forests, tree crowns are so close to each other that there is very little space for "exponential" expansion of tree crowns [8]. How can the nature of branch forking, which appears to result in an exponential increase of leaf amount, be consistent with crown development in closed hardwood stands where crown expansion is limited due to a lack of available space? To answer such a question, analyses of demographic (birth and death) and morphological patterns of annual shoots (the portion of shoots elongated during a year) in tree crowns are useful, since they can clarify how the shoot population in a crown develops and is maintained [1, 2,3,5,6, 7,9, 10,11,12,13]. Here, we begin by showing an example of the structural pattern of a branch as observed in the top canopy of a closed hardwood forest. We then show how the observed pattern can be formed by introducing a model simulating demographic and structural patterns of the annual shoots
A method of Screening Human Blood Catalase Activity
No full textAcatalasemia is the homozygote of an abnormal gene which is considered to be involved in the vital catalase synthesis of man, as discovered by Takahara in 1946. The hypocatalasemia which is a heterozygote of this abnormal gene, since its blood catalase activity is only about one half that of normal persons, has a characteristic of being accurately detected by the biochemical methods. In addition, it is of a great importance in the sense of gentics to determine its frequency by the cases of hypocatalasemia. As for the screening tests of this hypocatalasemia the titration with potassium permanganate has been mostly used, but the author devised a new method of determining catalase activities of the subjects by measuring the amount of oxygen gas produced from H(2)O(2) by the action of catalase, using the polarographic sensor. This method, compared with the available ones has a great advantage in that its accuracy, the ease of examinations and possible simultaneous screening tests with quantiative analysis are possible. Furthermore, this method is a superior one that it is easy to transport the test apparatus and conduct field examinations
Flow Properties of Wood Pulp Suspensions in Pipes
No full textThe flow of suspensions of wood pulp fibers in circular pipes has been investigated experimentally. The flow characteristics of pulp suspensions are discussed with regard to five flow regimes designated by the author. In particular, the effects of the shear stress at the pipe wall on the disruption and dispersion of networks of pulp fibers are examined. The values of the disruptive and dispersive shear stresses are formulated as simple expressions depending on only the fiber concentration. Furthermore, the flow properties of the suspensions are described using the yield shear stress
Breaking the Silence
No full textBreaking the Silence, written by Nikki Nojima Louis, is a readers theatre drama of Japanese immigration to the West Coast of the United States, the challenges of immigrants and a new culture, the hysteria during World War II (with the internment of the Japanese Americans at the camps), and the legal struggle of the constitutional redress.
The Seeking Justice Project focuses on the events and aftermath of the forced internment of thousands of Japanese Americans during World War II. Many of the Japanese Americans who lived in the Northwest were forced to leave behind homes, businesses, and property and were relocated to Camp Minidoka, an internment camp near Twin Falls, Idaho.
Production NoteHerbert Tsuchiya is credited in the video as both Herbert T Suchiya and Herbert Tsuchiya. Angie Bolton: music director, narrator, interrogator Chisao Hata: performing artist, dancer David Hsieh: professional director, performer, stage manager Nikki Nojima Lewis: author, artistic director, performer Stephen Sumida: actor Herbert Tsuchiya: artist, dancer, producer, performer Linfield College Taiko Drummers: Meghan Bauder, Ehren Cahill, Christopher Keaveney, Kayla Lindse
A Historical Critique of “Daiganmoku” : Review of materials relating to Kita Ikki
No full textapplication/pdfThe premise of the research on Kita-Ikki（1883─1937）is that there are no historical documents that systematically describe his thought since the early 1920s. The main purpose of this article is to solve this historical problem of research on Kita by estimating the authorship of the booklet “Daiganmoku” published on December 5, 1920.
The “Rodo Undo”（March 20, 1921）shows that “Daiganmoku” was written by Kita, but for some reason the signature was given as Sumida-Kiyohiko. In addition, the contents of “Daiganmoku” are explanations in simple language by the “author” about the contents of Kita’s previous books, which points out the strong relationship between Kita and “Daiganmoku”. In spite of these evidences, the author of “Daiganmoku” was presumed to be Sumida in previous studies, and “Daiganmoku” was not considered as a subject of Kita research.
“Daiganmoku” has been republished three times since its original publication, the last time in 1933, when it was renamed “Pure Nationalism”. In addition, “Daiganmoku” shows how the ideas of Kita influenced the right-wing activists during the period when he was active in Yuzonsha. This article is not only significant for solving the problem of consistency of thought that has existed in the history of research on Kita, but also contributes to the progress of research on the 2.26 Incident. It can be said that this article has opened up a new horizon for the study of Kita.departmental bulletin pape
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