7 resultados para 1764-1842
em Aquatic Commons
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Previously an asteroid starfish Astropecten indicus has been described by Tahera (1996), and another species of the genus Astropecten i.e. A. polyacanthus Muller and Troschel, 1842 has been collected from the subtidal region of a sandy shore of Clifton (24°47'42"N 66°59'6"E), Karachi. The latter species is here reported for the first time from the Pakistan coast of the northern Arabian Sea and fills the gap in the known distribution. The species is briefly described and illustrated.
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(4pp.)
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1 page
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Ephemera danica Müller, 1764 (Ephemeroptera) is one of the largest mayflies found in the British Isles with some females reaching over 30 mm. It is a common and widespread species found in rivers, lakes and streams throughout Europe and is particularly abundant in many of the lowland rivers of the British Isles. The larvae are burrowers – mainly found where silt accumulates below macrophytes. This article gives a general overview of research work on the factors affecting the life cycle of Ephemera danica over a seven year period (1995–2002) on two rivers, the River Test at Leckford in Hampshire and the North Wey at Tilford in Surrey.
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Spencer Fullerton Baird was born in Reading, Pennsylvania, February 3, 1823. In 1834 he was sent to a Quaker boarding-school kept by Dr. McGraw, at Port Deposit, Maryland, and the year following to the Reading Grammar School. In 1836 he entered Dickinson College, and was graduated at the age of seventeen. After leaving college, his time for several years was devoted to studies in general natural history, to long pedestrian excursions for the purpose of observing animals and plants and collecting specimens, and to the organization of a private cabinet of natural history, which a few years later became the nucleus of the museum of the Smithsonian Institution. During this period he published a number of original papers on natural history. He also read medicine with Dr. Middleton Goldsmith, attending a winter course of lectures at the College of Physicians and Surgeons, in New York, in 1842. His medical course was never formally completed, although in 1848 he received the degree of M. D., honoris causa, from the Philadelphia Medical College. In 1845 he was chosen professor of natural history in Dickinson College, and in 1846 his duties and emoluments were increased by election to the chair of natural history and chemistry in the same institution. In 1848 he declined a call to the professorship of natural science in the University of Vermont. In 1849 he undertook his first extensive literary work, translating and editing the text for the "Iconographic Encyclopedia," an English version of Heck's Bilder Atlas, published in connection with Brockhaus's Conversations Lexikon.
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Además de sus conocidos aportes a la geología, la paleontología y la biogeografía de ecosistemas terrestres de la región pampeana y la Patagonia (Argentina), Darwin realizó notables y poco difundidas contribuciones al conocimiento de los ambientes marinos costeros del actual territorio argentino y de los organismos que habitan en ellos. La intimidad de Darwin con el mar se advierte en toda su obra: en el Viaje y en el Origen igual que en numerosos trabajos de investigación realizados y publicados a su regreso a Inglaterra. Entre 1846 y 1854 dio a conocer una extensa obra sobre cirrípedos o cirripedios, que sentó las bases del estudio de esos crustáceos y, aún hoy, es bibliografía obligada de los taxónomos. Su trabajo sobre la estructura y distribución de los arrecifes coralinos de 1842, es considerado un documento fundacional del conocimiento sobre el origen de los atolones. Los moluscos fueron igualmente objeto de publicaciones y cartas entre 1848 y 1871. La difundida imagen de Darwin sentado ante un escritorio escribiendo sus libros lleva a olvidar que pasaba también mucho tiempo con el microscopio. En el Viaje del Beagle incluyó párrafos sobre aves marinas, lo mismo que sobre briozoos o briozoarios, y en El origen, explicó sus pensamientos acerca de la migración de los ojos en los lenguados. Dedicó especial atención a las algas gigantes o sargazos marinos de Tierra del Fuego (donde se los conoce por cachiyuyos). Se incluyen los siguientes trabajos de divulgación científica -Darwin y los briozoos; -Darwin y el desarrollo larval de crustáceos; -Sobre Cirripedios; De Darwin a los acelerómetros; -Los peces de cara torcida; -La incursión en la costa sur de Buenos Aires.
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A brief discussion is presented on epizootics and their containment in the aquaculture industry, in the form of a question-and-answer interview. Particular reference is made to activities carried out by the OIE (Office International des Epizooties), whose main activities include the provision of guidelines and standards for health protection applicable to international trade in live animals and their products. It has devised an early warning system to apprise its member countries of the occurence of disease outbreaks that would have serious repercussions on public health or the economics of animal products. URI