989 resultados para Biol
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This abstract summarises the 1953-1955 surveys of the distribution of benthos in the Rybinsk Reservoirs. It includes the mean biomass of benthos.
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Many have observed the reduction of the quantity of zooplankton in the presence of water blooms. It is known that in seas zooplankton as it were avoids places of accumulation of blue-green algae. By observations on one of the tributaries of the Rybinsk reservoir - the River Shumorovka - the authors tried by simultaneous collections to trace the changes in numbers, not only of zoo- and phytoplankton but also of bacteria. The plankton was collected by quantitative nets with suitable numbers of gauze and bacteria were taken account of by the method of direct calculation on membrane filters. It can be seen that the development of blue-green algae appears as an important factor, determining not only the intensity but also the direction of the process of production of zooplankton.
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This is a short excerpt of the original paper giving the key to the identification of the naupliar instars of the genus Cyclops.
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The feeding of freshwater copepods, especially cyclopoida, has been poorly covered in research so far. The majority of existing special works on the feeding of cyclopoida illustrate this question only from the qualitative side. The food content of the nauplius of freshwater cyclops has not been studied at all, as also the feeding of adult entomostracans on bacteria. Moreover the question of the suitability of vegetable food for Cyclops is not clear enough. This article aims to elucidate as fully as possible the nutrition of Acanthocyclops viridis (Jur.) - a large cyclops, inhabiting the mass of demersal layers of the open parts of the Rybinsk reservoir and its foreshore. The present work is devoted only to the predatory feeding of A. viridis, and includes data from the content of the intestines of cyclops, collected in natural conditions, and also the results of experimental observations carried out in a laboratory during 1958.
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The rhythm of division of 9 species belonging to different groups of algae were analysed in situ and in the laboratory. The research which developed in different environmental conditions attempted to establish the capacity for multiplication and assimilation of chlorophyll on the part of the algae under study with a view to placing them in a culture. The results obtained showed that the green multicellular algae (eg. Ulothrix) and the blue algae (eg. Lyngbya, Oscillatoria) are able to produce an appreciable quantity of dry matter, just as the unicellular algae. At the same time it arises that amongst the numerous factors of the environment, temperature plays one of the most important roles in the process of multiplication.
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This is a short excerpt of the original paper giving the key to the identification of the naupliar instars of the genus Cyclops.
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Histochemical experiments are conducted in order to study the interrenal cells of European brook lamprey (Lampetra planeri).
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The amphipods are major food items for many commercial fishes, and they are used as protein food for agricultural animals. In the present paper are presented the results of four-year observations on the feeding of Gammarus balcanicus in nature and in an aquarium. Among the studied aspects were the dependence of daily food ration on sex and physiological state (with and without eggs) and feeding on different kinds of plant food. The study concludes that Gammarus balcanicus willingly feed on soft half-decayed plant residues; into their ration also enters food of animal origin. In contrast to other amphipods, G. balcanicus eats representatives of its own species very rarely, and only dead or immobile ones.
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It is known that the larvae of Chironomidae in the first stages of life after leaving the egg case, swim for a long time in a body of water. Positive reaction in light, the capability of directed swimming and passive floating in suspension allow the larvae to temporarily carry out a planktonic way of life. This study describes the behaviour of Chironomus dorsalis larvae after leaving the egg case. The feeding of chironomid larvae in the first stages of development was also described.
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Se presenta experiencia educativa que propone la elaboraci??n de materiales relacionados con el ciclo formativo de grado superior sobre higiene bucodental. Se realiza en el IES Aynadamar en Granada. Los objetivos son: colaborar en la realizaci??n de estudios de salud comunitaria y realizar programas de prevenci??n bucodental. El proceso consta de varias fases: b??squeda de informaci??n y elaboraci??n de materiales; estudio de programas inform??ticos; elaboraci??n de un cuestionario para una encuesta sobre salud mental; estudio de la salud bucodental del alumnado del centro.
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Se publica el trabajo realizado como m??todo de trabajo para las escuelas rurales asturianas. Trata de fundamentar te??ricamente y ampliar los conocimientos pr??cticos que los alumnos tienen sobre las distintas t??cnicas de explotaci??n de los cultivos de la zona. Se ofrecen los objetivos espec??ficos del proyecto, los contenido a estudiar, tipos de tierra, semilleros, t??cnicas de cultivo, influencia de la luna, elaboraci??n de men??s tomando como base los cultivos de la zona, etc. Luego se ofrecen actividades para los alumnos divididas en propuestas para cada uno de los ciclos, Inicial, Medio y Superior de EGB y otras para todos los ciclos. La metodolog??a se basa en los siguientes principios: actividad, inducci??n, globalizaci??n, creatividad, individualizaci??n, socializaci??n e inter??s. La evaluaci??n se divide en inicial mediante preguntas directas a los alumnos, continua a trav??s de observaci??n directa y final eminentemente pr??ctica, comprobando si se ponen en pr??ctica lo que se hab??a estudiado en el aula.
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Los autores pretenden dar a conocer el medio caducifolio, t??pico de la Cordillera Cant??brica a trav??s de la Reserva Biol??gica de Muniellos y sensibilizar, de un modo divertido, al alumno sobre temas como el peligro de extinci??n del oso, la contaminaci??n de los rios, la escasez de montes naturales... proponen realizar un recorrido por el bosque de Muniellos dado su inter??s geol??gico y biol??gico as?? como por sus posibilidades pedag??gicas, se ofrecen unas recomendaciones iniciales para la utilizaci??n de la gu??a cuaderno as?? como para realizar el itinerario, se adjunta un mapa para dar una idea general de la Reserva y se dan las explicaciones oportunas de dicho mapa. A partir de ah?? comienza la explicaci??n y actividades a realizar durante todo el itinerario estudiando: el bosque, el robledal, las plantas con o sin flores, el acebo, el hayedo, el suelo, las rocas, las sendas, las lagartijas, invertebrados, renacuajos, babosas, las colmenas, el oso, el corzo, las centrales electricas, las aves, y, por ??ltimo, se ofrecen las claves para la determinaci??n de los ??rboles de Muniellos por sus hojas.
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Los dibujos son de Berroso, Guillermo; Cueto, Emilio; Fern??ndez, Pilar; Ferrer, Margarita
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Los dibujos son de Berroso, Guillermo; Cueto, Emilio; Fern??ndez, Pilar; Ferrer, Margarita. Se trata de una publicaci??n parecida a la de 1989