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Comparison of oil and egg tempera paint systems using time-of-flight secondary ion mass spectrometry
Zachary E. Voras Kristin deGhetaldi Brian Baade Eric Gordon Glenn Gates Thomas P. Beebe 《文物保护研究》2016,61(4):222-235
Time-of-flight secondary ion mass spectrometry (ToF-SIMS) is quickly becoming a critical tool in the field of art conservation. This technique provides high-resolution spatial maps of both inorganic and organic components located within cross-sectional samples collected from works of art. With recent advances in surface analysis, ToF-SIMS can now be used to identify specific amino acids present in protein-containing materials as well as fatty acids in drying oils. For example, the detection of the ion fragment associated with the amino acid hydroxyproline can be used to confirm the use of animal glue in a paint sample. As an analytical technique, ToF-SIMS avoids the need for derivatization/silylation reagents, with no interference by the presence of pigments. Furthermore, the layered systems that are often encountered in historical paint samples remain intact throughout the analytical procedure. This allows for the co-localization of organic and inorganic species in specific layers (e.g. egg yolk paint atop a glue ground). Because of this ability to localize the analytical signal to approximately 6?µm or less, the mass spectral information can be used to produce mass-resolved and spatially-resolve images which can be correlated to previous studies of the same samples. In this study, ToF-SIMS was used to analyze a paint cross section obtained from a painting attributed to Raphael, and another from a painting by the Sienese artist Matteo di Giovanni. 相似文献
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Brian Klebig Joanna Goldonowicz Elisa Mendes Ann Neville Miller James Katt 《Communication Research Reports》2016,33(2):152-158
This study investigated the combined role of instructor communication variables (nonverbal immediacy and self-disclosure), instructor credibility (competence, caring, and trustworthiness), and student personality traits (extraversion, neuroticism, agreeableness, conscientiousness, and openness) in predicting students’ uncivil behaviors in class. A total of 406 students completed online questionnaires regarding the instructor of the class they attended prior to the one in which the study was administered. Personality and instructor behavior variables contributed approximately equally to explaining variance in student incivility. Students’ conscientiousness and agreeableness had direct negative relationships with incivility, whereas instructors’ amount and negativity of self-disclosure had direct positive relationships with incivility. 相似文献
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Paul S. R. Goods Brian Dawson Grant J. Landers Christopher J. Gore Kevin Croft Peter Peeling 《European Journal of Sport Science》2016,16(8):1047-1054
This investigation examined the oxidative stress (F2-Isoprostane; F2-IsoP) and inflammatory (interleukin-6; IL-6) responses to repeat-sprint training in hypoxia (RSH). Ten trained male team sport athletes performed 3(sets)*9(repetitions)*5?s cycling sprints in simulated altitude (3000?m) and sea-level conditions. Mean and peak sprint power output (MPO and PPO) were recorded, and blood samples were collected pre-exercise, and again at 8 and 60?min post-exercise. Both MPO and PPO were significantly reduced in hypoxia (compared to sea-level) in the second (MPO: 855?±?89 vs. 739?±?95?W, p?=?.006; PPO: 1024?±?114 vs. 895?±?112?W, p?=?.010) and third (MPO: 819?±?105 vs. 686?±?83?W, p?=?.008; PPO: 985?±?125 vs. 834?±?99?W, p?=?.008) sets, respectively. IL-6 was significantly increased from pre- to 1?h post-exercise in both hypoxia (0.7?±?0.2 vs. 2.4?±?1.4?pg/mL, p?=?.004) and sea-level conditions (0.7?±?0.2 vs. 1.6?±?0.3?pg/mL, p?.001), with a large effect (d?=?0.80) suggesting higher IL-6 levels of post-hypoxia. F2-IsoP was significantly lower 1?h post-exercise in both the hypoxic (p?=?.005) and sea-level (p?=?.002) conditions, with no differences between trials. While hypoxia can impact on exercise intensity and may result in greater post-exercise inflammation, it appears to have little effect on oxidative stress. These results indicate that team sport organisations with ready access to hypoxic training facilities could confidently administer RSH without significantly increasing the post-exercise inflammatory or oxidative stress response. 相似文献
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Race walking is an Olympic event where no visible loss of contact should occur and the knee must be straightened until midstance. The purpose of this study was to analyse ground reaction forces of world-class race walkers and associate them with key spatiotemporal variables. Nineteen athletes race walked along an indoor track and made contact with two force plates (1000 Hz) while being filmed using high-speed videography (100 Hz). Race walking speed was correlated with flight time (r = .46, p = .049) and flight distance (r = .69, p = .001). The knee's movement from hyperextension to flexion during late stance meant the vertical push-off force that followed midstance was smaller than the earlier loading peak (p < .001), resulting in a flattened profile. Athletes with narrower stride widths experienced reduced peak braking forces (r = .49, p = .046), peak propulsive forces (r = .54, p = .027), peak medial forces (r = .63, p = .007) and peak vertical push-off forces (r = .60, p = .011). Lower fluctuations in speed during stance were associated with higher stride frequencies (r = .69, p = .001), and highlighted the importance of avoiding too much braking in early stance. The flattened trajectory and consequential decrease in vertical propulsion might help the race walker avoid visible loss of contact (although non-visible flight times were useful in increasing stride length), while a narrow stride width was important in reducing peak forces in all three directions and could improve movement efficiency. 相似文献
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Byron Egeland Brian Abery 《International Journal of Disability, Development & Education》1991,38(3):271-287
DATA FROM the Mother‐Child Project, a longitudinal study of high‐risk children, indicated that the percentage of children referred for school‐based problems was approximately 40% in grades one, two and three. Basically all of the children who were referred were receiving some form of educational services. Similarly, the majority of children achieving below the 25th percentile on a standardized achievement test were receiving special educational services. The reasons some of the low‐achieving students were not receiving services were higher social adjustment, better work habits and a past educational history of success as compared to those low‐achieving students who were receiving services. Greater differences between served and unserved groups were found on historical rather than current measures, which suggests that the chronicity of educational problems had a major impact in determining which students received services. The results suggest that across the large number of schools serving high‐risk children in our sample, excellent decisions were made in terms of who received special educational assistance. There did not appear to be any bias in the referral process or in making the decision of whom to serve. This finding contradicts the results of other investigators in this area. The results from the current investigation indicate that a high proportion of high‐risk children were having difficulty in school. We were encouraged to find, however, that the high‐risk students in need of special assistance were being served. 相似文献
18.
Roger Ellis 《Higher Education》1993,25(3):239-257
The setting of standards for teaching is identified as central to any system of quality assurance for teaching and learning. The paper describes a number of initiatives which have been taken at the University of Ulster to identify and develop quality in teaching. They include a project to identify teaching skills through consultation with expert teachers; the use of quality circles of staff and students to specify standards for teaching; the use of student feedback on teaching; the introduction of a distinguished teaching award; the assessment of teaching competence when staff are selected; the introduction of a unit-based in-service teacher training course; and the encouragement of self and peer evaluation using an appraisal schedule. Quality assurance for support services is considered and finally the University's initiatives are related to total quality management and BS 5750. 相似文献
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ABSTRACT This paper examines the impacts of co-residence (admitting women to men’s colleges and men to women’s colleges) at the University of Oxford beginning in the 1970s. Co-residence increased the representation of women undergraduates at Oxford to near parity with men; the representation of women in academic positions rose but not as substantially as that of women undergraduates and postgraduates and today women comprise still only a third of academics in the colleges of the university; the fellowships of the former female colleges became genuinely mixed, the fellowships of the former male colleges more slowly; women are less likely to be appointed head of a former men’s college than are men to be appointed head of a former women’s college; the quality of Oxford undergraduates rose with the increased number of female undergraduates; and the quality of undergraduates in the former male colleges rose at the expense of the female colleges. 相似文献
20.
Bullying is grounded in the interactions between an individual and complex social–ecological systems. Therefore, bullying involvement is not just confined to the classroom or school. Recent research suggests that sibling aggression may be a predictor for peer-level aggression. These findings may be more relevant for students with disabilities because studies suggest that students with disabilities are disproportionately involved in the bullying dynamic. Therefore, this study explored the intersection between sibling aggression and school belonging on bullying, victimisation and fighting for 14,508 students, including 1183 students with disabilities and 13,325 students without disabilities in grades 6 through 12. As hypothesised, students with disabilities reported higher levels of victimisation, bullying and fighting. Additionally, high levels of school belonging partially buffered fighting and bullying behaviours for students with and without disabilities. These findings demonstrate the importance of establishing an inclusive and safe environment for school-aged youth. 相似文献