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971.
Ghinea R Ugarte-Alvan L Yebra A Pecho OE Paravina RD Perez Mdel M 《Journal of Zhejiang University. Science. B》2011,12(7):552-562
This study deals with the influence of surface roughness on the color of resin composites. Ten resin composites (microfilled,
hybrid, and microhybrid) were each polished with 500-grit, 1 200-grit, 2 000-grit, and 4 000-grit SiC papers. The roughness
parameter (R
a) was measured using a Plμ confocal microscope, and field-emission scanning electron microscope (Fe-SEM) images were used
to investigate filler morphology. Color was measured using a spectroradiometer and a D65 standard illuminant (geometry diffuse/0°
specular component excluded (SCE) mode). Surface roughness decreased with grit number and was not influenced by filler size
or size distribution. A significant influence of R
a on lightness (L*) was found. Lightness increased with decreases in roughness, except for specimens that underwent polishing procedure 4 (PP4;
500-grit, 1 200-grit, 2 000-grit, and 4 000-grit SiC papers consecutively). Generally, it was found that surface roughness
influenced the color of resin composites. The composites that underwent PP1 (500-grit SiC paper) exhibited significant differences
in chroma (C*), hue (h°), and lightness (L*) compared to composites that underwent PP3 (500-grit, 1 200-grit, and 2 000-grit SiC papers consecutively) and PP4. Color
difference (ΔE*) between the polishing procedures was within acceptability thresholds in dentistry. 相似文献
972.
Gavin Boyce Angela Greenwood Amy Haworth Jacky Hodgson Chris Jones Gary Marsh Maria Mawson Rosa Sadler 《The Journal of Academic Librarianship》2019,45(5):102046
Over the course of 2018 the University of Sheffield Library conducted a series of interviews and workshops with stakeholders as part of a strategic project to reflect on the value of the university library in the 21st century. Using a mixed methodology, participants were asked to reflect upon the future Higher Education (HE) environment for the university and, for academic participants, their discipline. In this context participants were also asked to reflect upon the future value of the University Library in a series of questions designed to elicit value statements using a tool which the project group have called the ‘Wheel of Value’. The resulting reflections upon the future environment have been grouped into four categories reflecting the drivers for change; Digitalisation, Student Experience, Diversification and Collaboration recognizing that there is considerable overlap and interconnection between these. The reflections on the future value of the library are presented by Wheel of Value higher order categorization. This approach proved useful in eliciting responses from participants in the face of recognized difficulty in getting beyond current views of the library and the approach is recommended to other universities looking to carry out a similar project. The results of this research will be used to inform the development of a view of the library for the purpose of engaging with our university community and key partners. 相似文献
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Latinos are the largest minority group in the United States (U.S. Census, 2014), yet this term comprises individuals from multiple ethnicities who speak distinct varieties of Spanish. We investigated whether Spanish–English bilingual children (N = 140, ages 4–17) use Spanish varieties in their social judgments. The findings revealed that children distinguished varieties of Spanish but did not use Spanish dialects to make third-person friendship judgments until 10–12 years; this effect became stronger in adolescence. In contrast, young children (4–6 years) made friendship judgments based on a speaker's language (English, Spanish). Thus, using language varieties as a social category and as a basis for making social inferences is a complex result of multiple influences for Spanish-speaking children growing up bilingual in the United States. 相似文献
975.
Anne D. Lackritz Maria Cseh Donald Wise 《Mentoring & Tutoring: Partnership in Learning》2019,27(1):5-25
The purpose of our multi-case study was to understand the experiences of non-novice New York City and Washington, DC public charter school principals who had participated in leadership coaching as a component of their leadership development. Eight New York City and Washington DC public charter school principal cases were selected through purposeful sampling. Data were collected through semi-structured interviews, documents, and artifacts, which were analyzed, coded and grouped into three broader themes: the coaching process, the impact of coaching, and principal leader identity construction. The findings supported the following conclusions: (a) Participants’ experiences of coaching were inconsistent with the coaching literature; (b) The impact of coaching was shaped by perceived competencies of the coach and the structure of the coaching session; and (c) Participants’ leader identity construction was supported through the process of coaching. 相似文献
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Hyerim Oh Margaret Sutherland Niamh Stack Maria del Mar Badia Martín Sheyla Blumen Quoc Anh-Thu Nguyen 《High Ability Studies》2015,26(1):152-166
Previous empirical studies have yielded inconclusive results about peer perceptions of academically high performing students. The purpose of this study was to investigate students’ perceptions of the intellectual ability, positive social qualities, and popularity of a hypothetical new high performing classmate. Participants were 1060 Vietnamese, South Korean, British, Australian, Peruvian, and Spanish boys and girls in 10th grade. The results revealed that the perceptions of academically high performing classmates differed by country group. Positive perceptions of intellectual ability and social qualities were commonly found in all countries except the two Asian countries (Vietnam and South Korea), where the students reported more neutral views of high performers. In conclusion, it is argued that there is no evidence for possible iatrogenic effects of gifted education programs aiming at high achievements 相似文献
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