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Yuval Noah Harari 《中学历史教学参考》2021,(6):1-1
在7万年前,智人还不过是一种微不足道的动物,在非洲的角落自顾自地生活。但就在接下来的几千年间,智人就成了整个地球的主人、生态系统的梦魇。时至今日,智人似乎只要再跨一步就能进入神的境界,不仅有望获得永恒的青春,更拥有创造和毁灭一切的神力。但遗憾的是,智人在地球上的所作所为,实在没有太多令人自豪。 相似文献
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We present a microfluidic technique that generates asymmetric giant unilamellar vesicles (GUVs) in the size range of 2–14 μm. In our method, we (i) create water-in-oil emulsions as the precursors to build synthetic vesicles, (ii) deflect the emulsions across two oil streams containing different phospholipids at high throughput to establish an asymmetric architecture in the lipid bilayer membranes, and (iii) direct the water-in-oil emulsions across the oil–water interface of an oscillating oil jet in a co-flowing confined geometry to encapsulate the inner aqueous phase inside a lipid bilayer and complete the fabrication of GUVs. In the first step, we utilize a flow-focusing geometry with precisely controlled pneumatic pressures to form monodisperse water-in-oil emulsions. We observed different regimes in forming water-in-oil multiphase flows by changing the applied pressures and discovered a hysteretic behavior in jet breakup and droplet generation. In the second step of GUV fabrication, an oil stream containing phospholipids carries the emulsions into a separation region where we steer the emulsions across two parallel oil streams using active dielectrophoretic and pinched-flow fractionation separations. We explore the effect of applied DC voltage magnitude and carrier oil stream flow rate on the separation efficiency. We develop an image processing code that measures the degree of mixing between the two oil streams as the water-in-oil emulsions travel across them under dielectrophoretic steering to find the ideal operational conditions. Finally, we utilize an oscillating co-flowing jet to complete the formation of asymmetric giant unilamellar vesicles and transfer them to an aqueous phase. We investigate the effect of flow rates on properties of the co-flowing jet oscillating in the whipping mode (i.e., wavelength and amplitude) and define the phase diagram for the oil-in-water jet. Assays used to probe the lipid bilayer membrane of fabricated GUVs showed that membranes were unilamellar, minimal residual oil remained trapped between the two lipid leaflets, and 83% asymmetry was achieved across the lipid bilayers of GUVs. 相似文献
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In an attempt to confront monolithic perceptions of achievement and an educational narrative that defines communities of Color by their supposed deficits, the current study presents asset mapping as an example of culturally relevant pedagogy in action. Asset mapping is a pedagogical tool for students to visually represent personalized stories of their cultural assets and participate in a community-based gallery walk to showcase their maps. Interviews and focus groups with third- and sixth-grade teachers and students from an urban public school revealed learning about self, learning about others, and building community as emergent themes after completing the project. We present these themes and discuss asset mapping as a possible model for strength-based pedagogy that centers the lived experiences of students, their families, and their shared stories in classroom curriculum. 相似文献
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Noah Weeth Feinstein Pedro Roberto Jacobi Heila Lotz-Sisitka 《Environmental Education Research》2013,19(2):218-230
International policy analysis tends to simplify the nation state, portraying countries as coherent units that can be described by one statistic or placed into one category. As scholars from Brazil, South Africa, and the USA, we find the nation-centric research perspective particularly challenging. In each of our home countries, the effective influence of the national government on education is quite limited, particularly in fringe and emerging areas of education such as Education for Sustainable Development (ESD) and Climate Change Education (CCE). This essay explores how nation-level comparisons are and are not useful for international research on ESD and CCE. We consider several layers of decentralized governance, but ultimately come to the conclusion that ESD governance in our respective countries is polycentric rather than decentralized. We discuss the implications of this idea for cross-national policy research on ESD and CCE. 相似文献
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Sevinc Gelmez Burakgazi Ali Yildirim Noah Weeth Feinstein 《Journal of Science Education and Technology》2016,25(2):244-262
Rooted in science education and science communication studies, this study examines 4th and 5th grade students’ perceptions of science information sources (SIS) and their use in communicating science to students. It combines situated learning theory with uses and gratifications theory in a qualitative phenomenological analysis. Data were gathered through classroom observations and interviews in four Turkish elementary schools. Focus group interviews with 47 students and individual interviews with 17 teachers and 10 parents were conducted. Participants identified a wide range of SIS, including TV, magazines, newspapers, internet, peers, teachers, families, science centers/museums, science exhibitions, textbooks, science books, and science camps. Students reported using various SIS in school-based and non-school contexts to satisfy their cognitive, affective, personal, and social integrative needs. SIS were used for science courses, homework/project assignments, examination/test preparations, and individual science-related research. Students assessed SIS in terms of the perceived accessibility of the sources, the quality of the content, and the content presentation. In particular, some sources such as teachers, families, TV, science magazines, textbooks, and science centers/museums (“directive sources”) predictably led students to other sources such as teachers, families, internet, and science books (“directed sources”). A small number of sources crossed context boundaries, being useful in both school and out. Results shed light on the connection between science education and science communication in terms of promoting science learning. 相似文献
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Noah L. Schroeder John C. Nesbit Carlos J. Anguiano Olusola O. Adesope 《Educational Psychology Review》2018,30(2):431-455
A concept map is a node-link diagram in which each node represents a concept and each link identifies the relationship between the two concepts it connects. We investigated how using concept maps influences learning by synthesizing the results of 142 independent effect sizes (n = 11,814). A random-effects model meta-analysis revealed that learning with concept and knowledge maps produced a moderate, statistically significant effect (g = 0.58, p < 0.001). A moderator analysis revealed that creating concept maps (g = 0.72, p < 0.001) was associated with greater benefit relative to respective comparison conditions than studying concept maps (g = 0.43, p < 0.001). Additional moderator analyses indicated learning with concept maps was superior to other instructional comparison conditions, and was effective across science, technology, engineering, and math (STEM) and non-STEM knowledge domains. Further moderator analyses, as well as implications for theory and practice, are provided. 相似文献
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Children rely on both evidence and prior knowledge to make physical causal inferences; this study explores whether they make attributions about others' behavior in the same manner. A total of one hundred and fifty‐nine 4‐ and 6‐year‐olds saw 2 dolls interacting with 2 activities, and explained the dolls' actions. In the person condition, each doll acted consistently across activities, but differently from each other. In the situation condition, the two dolls acted differently for each activity, but both performed the same actions. Both age groups provided more “person” explanations (citing features of the doll) in the person condition than in the situation condition. In addition, 6‐year‐olds showed an overall bias toward “person” explanations. As in physical causal inference, social causal inference combines covariational evidence and prior knowledge. 相似文献