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Using ethnographic data collected in a second grade classroom over the course of a school year, this paper describes the ways in which one school's discourse of liberalism is deleteriously deployed. We view the school's discipline creed as emblematic of the school's liberal curriculum, and interrogate the effects on four African American boys in the classroom when the school enacts this creed. Despite the agency that these boys obviously had, they were unable to control the ways in which they were placed at a structural disadvantage and manipulated by a system far more powerful than they were. The results were that these four boys suffered. Not only did the intended liberal curriculum fail to be translated fully into the enacted curriculum, the liberal underpinnings of this curriculum precluded teachers and students from taking any critical stance. 相似文献
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Lioubov I. Tikhonova Igor I. Pottosin Karl-Josef Dietz Gerald Schönknecht 《The Plant journal : for cell and molecular biology》1997,11(5):1059-1070
In contrast to the vacuolar ion channels which are gated open by an increase of cytosolic Ca2+ the vacuolar ion currents at resting cytosolic Ca2+ are poorly explored. Therefore, this study was performed to investigate the properties of the so-called fast-activating vacuolar (FV) current which dominates the electrical characteristics of the tonoplast at physiological free Ca2+ concentrations. Patch—clamp measurements were performed on whole barley ( Hordeum vulgare ) mesophyll vacuoles and on excised tonoplast patches. Single ion channels were identified, which, based on their selectivity, activation kinetics, Ca2+ - and voltage-dependence, carry the whole-vacuole FV current. Reversal potential determinations indicated a K+ overs C− permeability ratio of about 30. Both inward and outward whole-vacuole currents as well as the activity of single FV channels were inhibited by an increase of cytosolic Ca2+ , with a Kd ≈ 6 µM. At physiological vacuolar Ca2+ activities, the FV channel is an outward-rectifying potassium channel. The FV channel was activated in less than a few milliseconds both by negative and positive potential steps, having a minimal activity that is 40 mV negative of the K+ equilibrium potential. It is proposed that transport of K+ through this cation channel controls the electrical potential difference across the tonoplast. 相似文献
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A biological method was used in addition to the chemical methods of identification in the screening programme of new antibiotics. The method consists of evaluation of the effect of the crude antibiotic preparations on microbial forms resistant to various antibiotics. The efficiency of the biological method is shown. It provides more complete and rapid characterization of the properties of the new antibiotics and their rough identification at early screening stages. 相似文献
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Richard W. Joy IV 《In vitro cellular & developmental biology. Plant》1995,31(3):176-177
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L S Tikhonova T I Samedov V Iu Galkin V V Babkov K A Makarov A G Efimov 《Antibiotiki i khimioterapii͡a》1990,35(1):27-30
Immobilization of antibiotics on the surface of electrolytically oxidated titanium was tried. Transfer of the immobilized ampicillin into hardly soluble calcium ampicillate resulted in providing the coating with antimicrobial activity for 5 days. The quantity of the immobilized antibiotic determined polarographically amounted to 6.4.10(-3) mol per 1 m2 of the surface. 相似文献
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Oshkin I. Yu. Danilova O. V. Suleimanov R. Z. Tikhonova E. N. Malakhova T. V. Murashova I. A. Pimenov N. V. Dedysh S. N. 《Microbiology》2021,90(5):588-597
Microbiology - The technology of single-cell protein production from natural gas is based on using thermotolerant methanotrophic bacteria with high growth rates on methane. So far, the spectrum of... 相似文献