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1.
ABSTRACT

Previously, heavy use of biocides for the treatment of objects made of organic materials in museum collections (e.g. ethnographic, historical collections) was very common. Now suitable decontamination methods/technologies are being sought. A decontamination treatment by li-CO2 was optimized that considered the specific requirements of museum objects. The treatment was tested on model materials artificially contaminated with biocide solutions containing dichlorodiphenyltrichloroethane (DDT), pentachlorophenol (PCP), lindane, and permethrin or cypermethrin. High decontamination was achieved for DDT, lindane, PCP, and permethrin on artificially biocide loaded wool and wood model materials. Optimal process parameter settings for li-CO2 decontamination include a single 30?min cycle for woolen materials and three sequential 30?min cycles each for wood. These methods allow a reduction of at least 90% of all biocides for wool and between 70% and 85% for wood. Decontamination of the latter was more effective for less polar biocides as DDT and permethrin. Despite a significant improvement in decontamination for wood using co-solvents such as acetone, ethanol, and methyl tertiary-butyl ether (MTBE), their use is not recommended due to the increased risk of damage to the objects, in particular if a surface coating is present.  相似文献   
2.
Past studies have explored the role of student science notebooks in supporting students' developing science understandings. Yet scant research has investigated science notebook use with students who are learning science in a language they are working to master. To explore how student science notebook use is co-constructed in interaction among students and teachers, this study examined plurilingual students' interactions with open-ended science notebooks during an inquiry science unit on condensation and evaporation. Grounded in theoretical views of the notebook as a semiotic social space, multimodal interaction analysis facilitated examination of the ways students drew upon the space afforded by the notebook as they constructed explanations of their understandings. Cross-group comparison of three focal groups led to multiple assertions regarding the use of science notebooks with plurilingual students. First, the notebook supported student-determined paths of resemiotization as students employed multiple communicative resources to express science understandings. Second, notebooks provided spaces for students to draw upon diverse language resources and as a bridge in time across multiple inquiry sessions. Third, representations in notebooks were leveraged by both students and teachers to access and deepen conceptual conversations. Lastly, students' interactions over time revealed multiple epistemological orientations in students' use of the notebook space. These findings point to the benefits of open-ended science notebooks use with plurilingual students, and a consideration of the ways they are used in interaction in science instruction.  相似文献   
3.
This study leverages naturally occurring lotteries for oversubscribed Boston Public Schools prekindergarten program sites between 2007 and 2011, for 3,182 children (M = 4.5 years old) to estimate the impacts of winning a first choice lottery and enrolling in Boston prekindergarten versus losing a first choice lottery and not enrolling on children’s enrollment and persistence in district schools, grade retention, special education placement, and third-grade test scores. There are large effects on enrollment and persistence, but no effects on other examined outcomes for this subsample. Importantly, children who competed for oversubscribed seats were not representative of all appliers and almost all control-group children attended center-based preschool. Findings contribute to the larger evidence base and raise important considerations for future prekindergarten lottery-based studies.  相似文献   
4.
达勒姆(Dahlem)不仅仅是一个传奇.在德国,几乎没有其他地方像柏林的这片土地那样,在科学史各个丰富的方面--包括令人质疑的方面--表现出如此强烈的活力.在马普学会历史档案馆馆长亨宁(Eckart Henning)的陪同下巡游他的“领地“,就如同在历史的时光中漫步,著名学者的创新精神始终伴随着我们的游程.……  相似文献   
5.
The present study was designed to explore the association between preschool academic skills and Grade 3 achievement among a sample of ethnically diverse children from low-income families. Data were collected from a sample of 1,442 low-income, ethnically diverse children in preschool and associated with Grade 3 achievement in reading and mathematics 4 years later. Mixed-effects modeling indicated that preschool skills significantly predicted Grade 3 achievement measures while controlling for various child-level factors and random school effects. While several preschool factors were predictive of Grade 3 achievement, writing/copying and counting/premathematics skills were consistently strong predictors of Grade 3 achievement across all measures and domains suggesting these are important foundational skills for academic success in midelementary school among low-income, ethnically diverse children. Findings also replicate studies demonstrating that writing plays an important role in learning and achievement. Findings have implications for early education policy and practice intended to support academic development among low-income, ethnically diverse children.  相似文献   
6.
This article investigates to what extent scholarships are unequally distributed among students in Germany and how these inequalities can be explained. Following sociological theory, the article argues that elites seek qualitative ways of distinguishing themselves in a mass higher education system. Using student surveys, we demonstrate that class effects cannot merely be explained with reference to class differences in academic achievement but that higher classes have better access to scholarships independent of earlier school performance. Class differences were particularly persistent when the intermediate classes were compared with higher classes with more education. These findings illustrate that social classes have different strategies when it comes to participating in higher education and suggest that information about and access to scholarships is important in gaining a class advantage.  相似文献   
7.
We describe the propagation of a technology-based educational innovation through its first 3 years of public use. The innovation studied is the Concept Warehouse (CW), a database-driven website developed to support the use of concept-based pedagogies. This tool was initially developed for instructors in undergraduate chemical engineering courses, but has spread to other disciplines as well. In this time, it has grown to over 650 registered instructors representing over 170 institutions. While this study is specific to a particular case, the intent of this article is to provide an exemplar of real-time propagation that informs other researchers and developers. We frame our analysis with Diffusion of Innovation Theory and use a design research methodology that focuses on communication channels, types of knowledge, and stages of the innovation-decision process. Data sources include usage records and survey responses which are analyzed with network diagrams and non-parametric statistics. We find that in comparison to mass media, interpersonal communications tended to result in higher proportions of how-to knowledge and implementation. Three types of opinion leaders were identified through user data and network diagrams. All played critical roles in the tool’s propagation, especially the project collaborators—opinion leaders who actively promoted the CW, in part, because it also propagates their own innovations. Finally, users with self-identified prior principles knowledge showed statistically significantly greater progress in gaining how-to knowledge, but no significant difference in progressing to the implementation stage of the innovation-decision process when compared to users without.  相似文献   
8.
We describe the development, implementation, and evaluation of a comprehensive preschool to third grade prevention program for the goals of sustaining services at a large scale. The Midwest Child–Parent Center (CPC) Expansion is a multilevel collaborative school reform model designed to improve school achievement and parental involvement from ages 3 to 9. By increasing the dosage, coordination, and comprehensiveness of services, the program is expected to enhance the transition to school and promote more enduring effects on well‐being in multiple domains. We review and evaluate evidence from two longitudinal studies (Midwest CPC, 2012 to present; Chicago Longitudinal Study, 1983 to present) and four implementation examples of how the guiding principles of shared ownership, committed resources, and progress monitoring for improvement can promote effectiveness. The implementation system of partners and further expansion using “Pay for Success” financing shows the feasibility of scaling the program while continuing to improve effectiveness.  相似文献   
9.
Journal of Science Education and Technology - We present lessons learned from an ongoing attempt to conceptualize, develop, and refine a way for teachers to gather formative assessment evidence...  相似文献   
10.
Research in Science Education - Science teaching and learning are discursive practices, yet analysis of these practices has frequently been grounded in theorizations that place language at the...  相似文献   
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