Cytotoxicity and effect of extraction methods on the chemical composition of essential oils of Moringa oleifera seeds     

Rowland Monday Ojo Kayode  Anthony Jide Afolayan 《Journal of Zhejiang University. Science. B》2015,16(8):680-689

Renewed interest in natural materials as food flavors and preservatives has led to the search for suitable essential oils. Moringa oleifera seed essential oil was extracted by solvent-free microwave and hydrodistillation. This study assessed its chemical constituents. Cytotoxicity of the oils was investigated using hatchability and lethality tests on brine shrimps. A total of 16 and 26 compounds were isolated from the hydrodistillation extraction (HDE) and solvent-free microwave extraction (SME) oils, respectively, which accounted for 97.515% and 97.816% of total identifiable constituents, respectively. At 24 h when the most eggs had hatched, values of the SME (56.7%) and HDE (60.0%) oils were significantly different (P<0.05) from those of sea water (63.3%) and chloramphenicol (15.0%). Larva lethality was different significantly (P<0.05) between HDE and SME oils at different concentrations and incubation periods. The median lethal concentration (LC₅₀) of the oils was >1000 mg/ml recommended as an index for non-toxicity, which gives the oil advantage over some antioxidant, antimicrobial, therapeutic, and preservative chemicals.  相似文献   

Identity: a complex structure for researching students’ academic behavior in science and mathematics     

Mehmet Aydeniz  Lynn Liao Hodge 《Cultural Studies of Science Education》2011,6(2):509-523

This article is a response to Pike and Dunne’s research. The focus of their analysis is on reflections of studying science post-16. Pike and Dunne draw attention to under enrollments in science, technology, engineering, and mathematics (STEM) fields, in particular, in the field of physics, chemistry and biology in the United Kingdom. We provide an analysis of how the authors conceptualize the problem of scientific career choices, the theoretical framework through which they study the problem, and the methodology they use to collect and analyze data. In addition, we examine the perspective they provide in light of new developments in the field of students’ attitudes towards science and mathematics. More precisely, we draw attention to and explicate the authors’ use of identity from the perspective of emerging theories that explore the relationships between the learner and culture in the context of science and mathematics.  相似文献   

Consistency of report card grades and external assessments in a Canadian province     

John A. Ross  Lynn Kostuch 《Educational Assessment, Evaluation and Accountability》2011,23(2):159-180

The study investigated how well report card grades communicate to students and parents that state educational standards are being met, standards that are objectively measured by infrequently administered mandated assessments. Data sources were report card grades and external assessment scores for 2006–09 for Ontario Canada. The information that parents and students received about student performance from report cards and external assessments were similar (r _s  = .47) to the r = .40–.60 range previously reported. Teachers assigned higher grades than external assessments warranted, even after a major source of construct irrelevant variance in report card grades (teacher ratings on multiple scales measuring student effort and school commitment) was controlled. The relationship of grades to assessment scores was robust across genders, school district types (Public versus Catholic) and language (English and French). Agreement of assessments was higher for grade 6 than for grade 3 and for Writing than for Reading or Mathematics. Report cards provided information about students’ future achievement that was accurate and delivered up to 2 years prior to the administration of external assessments. Seventy to 80% of students who reached the provincial achievement standard on one or both prior report cards were successful on the subsequent external assessment, compared to 30–50% of students who failed to meet the report card standard at least once.  相似文献   

Challenging Gender Stereotypes: Resistance and Exclusion          下载免费PDF全文

Kelly Lynn Mulvey  Melanie Killen 《Child development》2015,86(3):681-694

The likelihood of resisting gender‐stereotypic peer group norms, along with expectations about personal resistance, was investigated in 9‐ to 10‐year‐olds and 13‐ to 14‐year‐olds (N = 292). Participants were told about a stereotype conforming group (boys playing football; girls doing ballet) and a stereotype nonconforming group (boys doing ballet; girls playing football). Contrary to expectations from gender‐stereotyping research, participants stated that they would personally resist gender‐stereotypic norms, and more so than they would expect their peers to resist. However, expecting peers to resist declined with age. Participants expected that exclusion from the group was a consequence for challenging the peer group, and understood the asymmetrical status of gender stereotypes with an expectation that it would be more difficult for boys to challenge stereotypes than for girls.  相似文献   

Thai pre-service science teachers engaging action research during their fifth year internship     

Chatree Faikhamta  Anthony Clarke 《Asia Pacific Journal of Education》2015,35(2):259-273

As a key element in teacher education programmes, action research is a learning process in which pre-service teachers inquire, reflect on and improve their teaching practices. This qualitative study sought to understand what enhanced or hindered Thai pre-service teachers' action research projects during their student teaching. This study drew upon written reflections, focus-group interviews and observations of seminar sessions. Data analysis was inductive, involving categorical aggregation followed by a search for correspondence and patterns. The results indicated that the pre-service teachers misunderstood action research, and also held a negative attitude toward it, both of which led them to superficial analyses of practice. They struggled with time limitations, data gathering and interpretation strategies. In spite of the struggles they experienced, these pre-service science teachers did learn more about the action research through collaboratively working with cooperating teachers and university supervisors and on-campus seminar discussions held concurrently with the fifth year internship. Recognizing and understanding the reasons and thinking patterns at the root of these teachers' difficulties with learning about action research can form the basis for reflecting on and rethinking the components of science teacher preparation programmes in Thailand.  相似文献   

Towards shaping the field: theorising the knowledge in a formal course for academic developers     

Jo-Anne Vorster  Lynn Quinn 《高等教育研究与发展》2015,34(5):1031-1044

In recent years there have been calls both for building the knowledge base of academic development (AD) and for systematic induction of newcomers to the field if AD is to advance as a professional and an academic field. Despite the importance and complexity of AD, induction of novice academic developers remains mostly informal and predominantly focuses on the practices of the field. We argue that more-experienced academic developers have an obligation to provide formal and systematic routes into the field and its knowledge base than is currently the case. One way of doing this is through offering a formal course for growing the next generation of academic developers. Such a course could equip newcomers with a more solid and shared knowledge base, thus contributing to shaping the epistemic spine of AD. In this paper, using Maton's Legitimation Code Theory, we offer an analysis of an existing course aimed at equipping novices with the theoretical and practical knowledge to enable them to solve some of the problems in higher education. From this analysis have emerged general principles that could inform the selection, sequencing and pacing of knowledge in a formal course for academic developers.  相似文献   

Ruling by schooling Quebec: conquest to liberal governmentality – a historical sociology     

Anthony Di Mascio 《History of education》2015,44(1):126-128

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The stickup kids: race,drugs, violence,and the American dream     

Anthony A. Peguero 《Journal of Criminal Justice Education》2015,26(1):117-119

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Embracing Students as Equal Stakeholders in a Culture of Assessment          下载免费PDF全文

Anthony C. Marziliano  Gina M. LaPan‐Dennis  S. William Zito  Marc E. Gillespie 《Assessment Update》2015,27(1):6-13

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Boarding schools: A longitudinal examination of Australian Indigenous and non-Indigenous boarders’ and non-boarders’ wellbeing     

Anthony Dillon  Rhonda G. Craven  Jiesi Guo  Alexander S. Yeung  Janet Mooney  Alicia Franklin  Rob Brockman 《British Educational Research Journal》2022,48(4):751-770

Improving educational outcomes for Indigenous Australian students is a key strategy to helping Indigenous people reach their full potential. This has resulted in well-intentioned efforts by Australian educators and governments to ensure Indigenous children have positive school experiences. However, Indigenous students still lag behind their non-Indigenous counterparts in educational outcomes. This is particularly so for Indigenous students living in rural and remote parts of Australia where educational opportunities are limited, especially in high school. One solution to this problem has been to enrol these students in boarding schools in urban and metropolitan centres. While research on the success of boarding schools for Indigenous students is scarce, what little that does exist is not encouraging. The focus of this research was to examine the effects of boarding for Indigenous (n = 11) and non-Indigenous students’ (n = 158) wellbeing (N = 1423) in two large private boys’ schools. Participating students aged 12–18 years old completed a survey measuring wellbeing constructs on two occasions, 12 months apart. Non-Indigenous boys were generally higher in wellbeing compared with Indigenous boys. There was also evidence of improved social wellbeing beyond that of non-Indigenous boarders over time. Overall, while evidence of merit was weak, boarding schools may benefit their Indigenous students’ development in social wellbeing.  相似文献