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1.
Proc Natl Acad Sci U S A ; 117(12): 6476-6483, 2020 03 24.
Artículo en Inglés | MEDLINE | ID: mdl-32152114

RESUMEN

We tested the hypothesis that underrepresented students in active-learning classrooms experience narrower achievement gaps than underrepresented students in traditional lecturing classrooms, averaged across all science, technology, engineering, and mathematics (STEM) fields and courses. We conducted a comprehensive search for both published and unpublished studies that compared the performance of underrepresented students to their overrepresented classmates in active-learning and traditional-lecturing treatments. This search resulted in data on student examination scores from 15 studies (9,238 total students) and data on student failure rates from 26 studies (44,606 total students). Bayesian regression analyses showed that on average, active learning reduced achievement gaps in examination scores by 33% and narrowed gaps in passing rates by 45%. The reported proportion of time that students spend on in-class activities was important, as only classes that implemented high-intensity active learning narrowed achievement gaps. Sensitivity analyses showed that the conclusions are robust to sampling bias and other issues. To explain the extensive variation in efficacy observed among studies, we propose the heads-and-hearts hypothesis, which holds that meaningful reductions in achievement gaps only occur when course designs combine deliberate practice with inclusive teaching. Our results support calls to replace traditional lecturing with evidence-based, active-learning course designs across the STEM disciplines and suggest that innovations in instructional strategies can increase equity in higher education.


Asunto(s)
Logro , Grupos Minoritarios/educación , Aprendizaje Basado en Problemas , Evaluación Educacional , Ingeniería/educación , Humanos , Matemática/educación , Ciencia/educación , Estudiantes , Tecnología/educación , Estados Unidos , Universidades
2.
J Exp Med ; 217(2)2020 02 03.
Artículo en Inglés | MEDLINE | ID: mdl-31748243

RESUMEN

CD4+ T follicular helper (Tfh) cells dominate the acute response to a blood-stage Plasmodium infection and provide signals to direct B cell differentiation and protective antibody expression. We studied antigen-specific CD4+ Tfh cells responding to Plasmodium infection in order to understand the generation and maintenance of the Tfh response. We discovered that a dominant, phenotypically stable, CXCR5+ Tfh population emerges within the first 4 d of infection and results in a CXCR5+ CCR7+ Tfh/central memory T cell response that persists well after parasite clearance. We also found that CD4+ T cell priming by B cells was both necessary and sufficient to generate this Tfh-dominant response, whereas priming by conventional dendritic cells was dispensable. This study provides important insights into the development of CD4+ Tfh cells during Plasmodium infection and highlights the heterogeneity of antigen-presenting cells involved in CD4+ T cell priming.


Asunto(s)
Linfocitos B/inmunología , Malaria/inmunología , Plasmodium yoelii/genética , Linfocitos T Colaboradores-Inductores/inmunología , Animales , Anticuerpos Antiprotozoarios/inmunología , Antígenos de Protozoos/inmunología , Células Cultivadas , Células Dendríticas/inmunología , Epítopos de Linfocito T/genética , Epítopos de Linfocito T/inmunología , Memoria Inmunológica , Activación de Linfocitos/inmunología , Malaria/parasitología , Masculino , Ratones , Ratones Endogámicos C57BL , Organismos Modificados Genéticamente , Fenotipo , Receptores CCR7/metabolismo , Receptores CXCR5/metabolismo
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