1000 resultados para Breckinridge, William Campbell Preston, 1837-1904.


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Observations were made on 100 female Aedes fluviatilis (Lutz) maintained individually from the first blood meal onwards and allowed one blood meal during each oviposition cycle, 5% dextrose solution been supplied throughout life. The average length of live was 49.9 ± 17.8 days; the logarithm of the mortality rate increased proportionately to physiological age. The insects took an average of 7.3 ± 3.2 blood meals and produced a mean of 7.9 ± 3.7 clutches of eggs. There was a progressive decrease, proportional to advancing physiological age, in the mean numbers of eggs laid in successive oviposition cycles, in the intervals between blood feeding oviposition, and in the numbers of larvae that hatched. Delayed oviposition, transient sterility and a total loss of fertility were also recorded.

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Com o intuito de acrescentar parâmetros à taxonomia do gênero Sirthenea Spinola, 1837, realizamos uma análise morfológica comparativa da genitália externa dos machos de quatro espécies: S. carinata (Fabricius, 1798), S. stria (Fabricius, 1794), S. flavipes (Stal, 1855) e S. amazona Stal, 1866. Foram evidenciadas 10 estruturas (8º esternito, processo do pigóforo, parâmeros, falosoma e seus quatro processos e os dois processos do endosoma) que permitem diferenciar as quatro espécies. Uma descrição resumida da morfologia geral de cada espécie é adicionada.

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Description of Mycotretus lopesi sp. n., from the Amazon region (Brazil, Pará).

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Based on type examination, Culex (Melanoconion) theobaldi (Lutz, 1904) is redescribed. The species Cx. (Mel.) chrysonotum Dyar & Knab, 1908, was put back as synonym of theobaldi. Besides, examination of Cx. (Mel.) chrysothorax (Newstead & Thomas, 1910) type, leads to retiring as synonym of theobaldi and considered it as "species inquirenda".

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La Real Compañía de Canalización del Ebro, sociedad anónima constituida en 1852 con un capital nominal de 31,5 millones de pesetas, que tenía como objetivo fundamental abrir el Ebro a la navegación a vapor en base a un proyecto técnico elaborado por ingenieros franceses, tuvo que recurrir a inversores europeos para levantar su capital. Se trataría, pues, de una empresa equiparable en muchos aspectos –inversión en comunicaciones, elevado capital, dependencia de técnicos e inversores europeos– a las grandes compañías ferroviarias constituidas en España a mediados del siglo XIX. El fracaso en la navegación reorientó su actividad hacia el riego, siendo la empresa encargada de construir y explotar hasta 1966 estas infraestructuras en el Delta del Ebro. En este texto, después de referirnos a los diferentes intentos de canalización del Ebro relacionados con la navegación hasta mediados de siglo XIX, analizaremos los motivos de su evolución y la diferente actitud mantenida ante las oportunidades de negocio por los dos grandes sectores de accionistas, el capital catalán y el capital francés, hasta la salida de este último ocurrida entre 1878 y 1904. Asimismo, intentaremos mostrar como el ritmo de la inversión en la canalización se ajusta al de la inversión francesa en España, que iniciada en el siglo XVIII, se paraliza con la crisis del Antiguo Régimen, se intensifica a partir de la década de 1840 orientándose mayoritariamente hacia los sectores ferroviario y minero, e inicia un cierto repliegue a partir de la última década del siglo XIX.

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Biomphalaria prona from Lake Valencia, Venezuela (type locality) has a polymorphic shell wich in the great majority of specimens is wider, with fewer rapidly expanding whorls, the outer one subcarinate on the left side and more or less strongly deflected leftward. Besides those modal forms there are little frequent variants characterized by narrower shell with less rapidly expanding, regularly curved whorls directed forward. Recent studies have shown that such variants constitute the predominant shell phenotype in extralacustrine populations, but are anatomically and biochemically indistinguishable from the modal class of the Lake. In the present paper it is demonstrated that the nominal species Planorbis meridaensis Preston, 1907, from Mérida, Venezuela, is identical with B. prona (Martens, 1873) of wich it must be considered a junior synonym.