999 resultados para 92-600C


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The spectroscopic properties of (Y0.92-xLa0.08Ndx)(2)O-3 transparent ceramics were investigated. According to three intensity parameters (Omega(2),Omega(4),Omega(6)) fitted by the Judd-Ofelt theory, the spectroscopic quality parameter (X-Nd), branching ratio (beta(J,J')), and quantum efficiency (eta) of Nd3+ were determined. It was found that X-Nd of the host, owing to the additive La2O3, was decreased from 1.6 to 0.46; thus beta(J,11/2) was increased from 46% to 56.82%. A figure of merit of the specimens was discussed and compared with Nd:YAG transparent ceramic. (c) 2007 Optical Society of America.

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In 1988, the Oregon Department of Fish and Wildlife began sampling and monitoring the development of a new fishery for Pacific hagfish, Eptatretus stouti, and black hagfish, E. deani. Hagfish landings by Oregon trap vessels have ranged from 11,695 kg in 1988 to 340,774 kg in 1992. Whole frozen fish were shipped to South Korea for the "eel skin" leather market. From 1988 through 1989, I sampled 924 Pacific hagfish and 897 black hagfish from commercial and research catches. Mean length of fish sampled from commercial landings was 39.6 cmf or Pacific hagfish and 34.5 cm for black hagfish. Weight-length relationships (W=aLb) were calculated for males and females of both species. Fifty percent maturity for male and female Pacific hagfish was 35 cm and 42 cm, respectively, while 50% maturityf or male and female black hagfish was 34 cm and 38 cm, respectively. Examination of gonads for both species indicated that spawning either occurs throughout the year or the spawning period is protracted. Mature females of both species had from one to three distinct sizes of eggs, but they usually carried only one group of eggs over 5 mm in length. Mature Pacific hagfish females averaged 28 eggs over 5 mm in length, and black hagfish females averaged 14 eggs over 5 mm in length. Hermaphroditism was found in 0.2% of the Pacific hagfish examined.

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EXTRACT (SEE PDF FOR FULL ABSTRACT): The latest in a series of unusual winters affected the western United States during 1991-92. This report is primarily concerned with the 6 to 8 coolest months, with some consideration of the adjacent summer months. ... Much of the winter was characterized by "split flow" west of North America. As it approached the West Coast, the jet stream frequently diverged into a northern branch toward Panhandle Alaska and a second southern branch that dived south along the California coast and then eastward along the US-Mexican border. Repeatedly, storms approaching the West Coast were stretched north-to-south, losing their organization in the process.

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Lake wamala was opened to commercial fishing in 1960. Interviews with the local fishermen during 1975/78 (Okaronon 1975, 1976, 1977, 1989) revealed that fishing for subsistence had been going on long before stocking was done. The subsistence fishing was conducted along rivers and at river mouths using basket traps (mainly made of papyrus stems), weirs and hooks and that the fish species caught were predominantly clarias (mudfish/male) and protopterus Lungfish/Mamba). These interviews did not, however, reveal the presence of tilapiine species in Lake wamala prior to stocking. These interviews did not however reveal the presence of tillapine species in lake wamala prior to stocking. Following the opening of the lake to commercial fishing in 1960, Lake Wamala provided a very profitable commercial fishery throughout the 1960s. However, during the early 1970s the fishermen started complaining of continued decline in catch rates from about 8 kg (15 fish) of O. niloticus per net per night if in 1966 to less than 1 kg per net per night by 1975.

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Geo-morphology, ecology and fish production of the 92 rivers of Rajshahi division have been presented in this paper. Fifteen rivers are dead and 11 rivers have severe erosion problem. Siltation has increased in 66 rivers and depth has decreased in 11 rivers. Sixty nine rivers are suffering from low flow conditions. Fish diversity has decreased in 20 rivers while fish production has declined in 75 rivers. A total of 31 fish species have extinct, 25 species are under threat of extinction and 43 species have low production. Siltation and pollution are the major causes of fish habitat loss. Recommendations are made to protect and conserve fish habitat and riverine fisheries of Rajshahi division.

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Two-electron-one-photon (TEOP) M1 and E2 transition energies, line strengths and transition probabilities between the states of the 2p(3) and 2s(2)2p odd configurations for B-like ions with 18 <= Z <= 92 have been calculated using the GRASP2K package based on the multiconfiguration Dirac-Hartree-Fock (MCDHF) method. Employing active-space techniques to expand the configuration list, we have systematically considered the valence, core-valence and core-core electron correlation effects. Breit interaction and quantum electrodynamical (QED) effects were also included to correct atomic state wavefunctions and the corresponding energies. Influences of electron correlation, Breit interaction and QED effects on transition energies and line strengths of the TEOP M1 and E2 transitions were analysed in detail. The present results were also compared with other theoretical and experimental values.

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Ferric uptake regulator (Fur) is a global regulator involved in multiple aspects of bacterial life. The gene encoding the Vibrio harveyi Fur (Fur(vh)) was cloned from a pathogenic V. harveyi strain isolated from diseased fish. Furvh shares 77% overall sequence identity with the Escherichia coli Fur (Fur(Ec)) and could complement a mutant of Fur(Ec). Like Fur(Ec), Fur(Vh), possesses two cysteine residues at positions 92 and 95, yet unlike Fur(Ec), in which these cysteine residues constitute part of the metal ion coordination site and hence are vital to the repressor activity, C92 and C95 of Fur(Vh) proved to be functionally inessential. Further study identified a Vibrio Fur signature sequence, which is preserved in all the ten Vibrio Fur proteins that have been discovered to date but in none of the non-vibrio Fur proteins. Site-directed and random mutation analyses of the signature residues, the cysteine residues, and seven highly charged amino acid residues indicated that D9, H32, C137, and K138 of Fur(vh) are functionally important but D9, C137, and K138 can be replaced by more than one functional substitutes. Systematic deletion analysis demonstrated that the C-terminal 12 residues of Fur(Vh) are functionally inessential. These results (i) indicated that the activation mechanism, or certain aspects of which, of Fur(Vh) is possibly different from that of Fur(Ec); and (ii) suggested that it is not very likely that the C-terminal 12 residues play any significant role in the activation or stability of Fur(Vh); and (iii) provided insights into the potential function of the local structure involving C137 and K138.

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Se presentan en este reporte algunos resultados obtenidos en el aula de matemática a propósito del desarrollo de la situación problema: ¿Qué relación existe entre el ángulo en posición normal y el cociente del lado opuesto y la hipotenusa del triángulo rectángulo? (Fig. 1) Esta actividad se implementó con el objetivo de contribuir al desarrollo del pensamiento variacional de los alumnos de 10º grado jornada de la tarde del Colegio Nacional Loperena de Valledupar, a través de la mediación instrumental de la calculadora algebraica TI-92+ y el uso de las distintas representaciones semióticas para movilizar el aprendizaje de la red conceptual subyacente a la función Seno.

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La introducción a la clase de matemáticas de la calculadora TI 92 Plus y otros dispositivos, tales como el CBR, están generando una nueva cultura matemática, caracterizar algunos rasgos de éste fenómeno educativo en la modelación del movimiento pendular es el propósito central de la presente investigación. El trabajo de los estudiantes permitió observar en la práctica los constitutivos del marco teórico del proyecto de incorporación de nuevas tecnologías al currículo de matemáticas de Colombia, como son: mediación instrumental, representaciones ejecutables, cognición situada, solución de problemas, fluidez algorítmica y fluidez conceptual.

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En el trabajo que hemos venido realizando en las pasantías de extensión, pretendemos desarrollar parte de la trigonometría desde la época griega hasta la actualidad; tomando como eje central la proporcionalidad, basados en una metodología de resolución de problemas e implementado la calculadora T.I.- 92 Plus en el aula. Para llevar a cabo este proyecto, diseñamos una serie de actividades enfocadas a desarrollar el concepto de proporcionalidad, trabajando desde la semejanza de triángulos. Este enfoque permite al estudiante, por medio de sus experiencias, construir un conjunto de herramientas que le contribuya no sólo enfrentarse a una situación problema, sino que también le ayude a desarrollar su comprensión y habilidad matemáticas.