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A. Velázquez H. Andreu N. Xamena A. Creus R. Marcos 《Cellular and molecular life sciences : CMLS》1987,43(10):1122-1123
Summary Viability tests were performed on second and third chromosomes from lines ofDrosophila melanogaster selected for increased resistance to the organophosphorus insecticides dichlorvos and malathion, in order to evaluate the accumulation of drastic alleles. Our results show that malathion reduces significantly the relative viability of chromosome 3 and also increases the frequency of drastic alleles in this chromosome, while dichlorvos increases significnatly the frequency of drastic alleles in chromosome 2.Work supported in part by the Spanish Ministry of Education and Science (Grant No. 0577/84 CAICYT).—We are grateful to Productos Cruz Verde S.A. and Agrocrós S.A. for generously supplying the insecticides dichlorvos and malathion, respectively. 相似文献
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P. Sánchez-García A. Velasco Martín B. L. Velázquez 《Cellular and molecular life sciences : CMLS》1970,26(6):635-636
Resumen El contenido de catecolaminas de la auricula de cobayos tratada con Iproniazida e incubada con nor-epinefrina disminuye significativamente cuando se suspenden en un medio deficiente en sodio (25 mM). En estas condiciones el efecto liberador de norepinephrine inducido por tiramina desaparece.
This investigation was supported by a research grant from the Instituto Nacional de Prevision, Seguridad Social, Madrid (Spain). 相似文献
This investigation was supported by a research grant from the Instituto Nacional de Prevision, Seguridad Social, Madrid (Spain). 相似文献
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An extant, indigenous desert tortoise population is reported from the cape region of Baja California Sur, Mexico. This population is described and figured as a new species, Xerobates lepidocephalus , distinct from all other North American tortoises including Xerobates agassizii , X. berlandieri , Gopherus flavomarginatus , and G. polyphemus . Xerobates lepidocephalus , or the scaly-headed tortoise, whose range is known only from an extremely small area in the gulf-drainage mountains just south of La Paz, appears to be a peninsular relict whose closest living relative is probably X. agassizii . However, carpal bone affinities connote a close relationship between X. lepidocephalus and the Oligoeene species X. laticunea from Wyoming and Colorado, suggesting that the former species may be one of the more primitive contemporary tortoises of the Xerobates lineage. Such evidence indicates that X. lepidocephalus is not of vicariant origin resulting from the formation of the cape of Baja California. Scaly-headed tortoises likely ranged, and may yet be discovered, in other medium-elevation mountain ranges of the cape. 相似文献
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Alternative beneficiation of tantalite and removal of radioactive oxides from Ethiopian Kenticha pegmatite-spodumene ores 下载免费PDF全文
Berhe Goitom Gebreyohannes Vel zquez del Rosario Alberto Abubeker Yimam Girma Woldetinsae Bogale Tadesse 《矿物冶金与材料学报》2017,24(7):727-735
The beneficiation methods for Ethiopian Kenticha pegmatite-spodumene ores were assessed through mineralogical and quantitative analyses with X-ray diffraction (XRD) and energy-dispersive X-ray fluorescence (EDXRF). The tantalite in the upper zone of the Kenticha pegmatite-spodumene deposit is 58.7wt% higher than that in the inner zone. XRD analysis revealed that the upper zone is dominated by manganocolumbite, whereas the inner zone is predominantly tantalite-Mn. Repeated cleaning and beneficiation of the upper-zone ore resulted in concentrate compositions of 57.34wt% of Ta2O5 and 5.41wt% of Nb2O5. Washing the tantalite concentrates using 1vol% KOH and 1 M H2SO4 led to the removal of thorium and uranium radioactive oxides from the concentrate. The findings of this study suggest that the beneficiation and alkaline washing of Kenticha pegmatite-spodumene ores produce a high-grade export-quality tantalite concentrate with negligible radioactive oxides. 相似文献
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Velásquez-Rodríguez Camilo Payán-Durán Luisa 《Systemic Practice and Action Research》2022,35(1):33-53
Systemic Practice and Action Research - An organizational design proposal is made for Creo en el Agro, an organization made up of small coffee growers who were victims of the armed conflict in the... 相似文献
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