969 resultados para British Naval History


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A diminutive species of Aglaothamnion (Ceramiaceae, Rhodophyta), A. diaphanum sp. nov., is described from Brittany (Atlantic France), the Isles of Scilly (off S.W. England) and western Ireland. Aglaothamnion diaphanum is confined to the sublittoral zone, where it grows almost exclusively on algae and sessile animals attached to hard substrata. Thalli are delicate, and branched distichously in one plane. The main axes are ecorticate but may form loose non-corticating rhizoidal filaments. The lateral branches bear a characteristic, regularly alternate distichous series of branchlets, the first of which is always adaxial. All vegetative cells are uninucleate. The majority of field-collected plants bear only bisporangia, but a few bisporangial plants also form spermatangia; some male plants and a single female specimen have been collected. The spermatangial branchlets consist of 3-5 spermatangial mother cells each bearing 2-4 spermatangia, which are constricted around a central nucleus. None of the U-shaped carpogonial branches showed any sign of fertilization, and the gametangia appear to be non-functional. The bisporangia are ovoid and contain two uninucleate spores separated by an oblique curved wall. The occurrence of bisporangia and the lack of adherent cortication distinguish A. diaphanum from two similar species, Aglaothamnion bipinnatum (P. Crouan et H. Crouan) Feldmann-Mazoyer and Aglaothamnion decompositum (J. Agardh) Halos. The life history in culture of French and Irish isolates of A. diaphanum consists of a series of bisporangial generations, a single plant of which also formed spermatangia. Apical cells of bisporophytes are haploid (n = c. 32), but the first division of meiosis, with chromosome pairing and crossing over, occurs in dividing bisporocytes. The germinating bispores are haploid. Endodiploidization may occur in the early stages of sporangium development, as in some phycomycete fungi, or in vegetative cells that subsequently give rise to bisporocytes. This is the first demonstration in the red algae of meiotic bisporangia on plants of which the apical cells, at least, are haploid.

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A monograph on British theatre historiography from its emergence in the Restoration to its foundation as an academic discipline in the early 20th century.

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"A list of British vessels captured by the United States' sloop of War Wasp, J. Blakeley esg. commander, between May 1st and July 6th, 1814".Folded table at end. October 17, 1814. Printed by order of the Senate of the United States.

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Veinte siglos de historia del mundo y de historia británica organizados cronológica y temáticamente en este Atlas de Historia. Contiene temas claves para estudiantes de secundaria desde el Imperio Romano y China Antigua hasta los conflictos del mundo y las operaciones pacificadoras en 1990.

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Es una de las cuatro unidades del curso de preparación para los exámenes del General Certificate Secondary Education (GCSE). Esta unidad 3 es diferente de las dos unidades anteriores pues sus temas se basan en comprender la importancia de las fuentes en el estudio de la historia y como pueden ser interpretadas de varias maneras, lo que lleva a los historiadores a emitir juicios sobre la utilidad y fiabilidad de la información que proporcionan. Asimismo, se explica que en esta parte del examen del GCSE se conjugan los conocimientos y la información sobre los hechos con los juicios sobre las fuentes históricas.

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Es una de las cuatro unidades del curso de preparación para los exámenes del General Certificate Secondary Education (GCSE). Esta unidad 3 es diferente de las dos unidades anteriores pues sus temas se basan en comprender la importancia de las fuentes en el estudio de la historia y como pueden ser interpretadas de varias maneras, lo que lleva a los historiadores a emitir juicios sobre la utilidad y fiabilidad de la información que proporcionan. Asimismo, se explica que en esta parte del examen del GCSE se conjugan los conocimientos y la información sobre los hechos con los juicios sobre las fuentes históricas.