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To investigate the influence of microwave radiation on the human fibroblast nuclei, the effects of three variants of electromagnetic wave polarization, linear and left-handed and right-handed elliptically polarized, were examined. Experimental conditions were: frequency (f) 36.65 GHz, power density (P) at the surface of exposed object 1, 10, 30, and 100 μW/cm2, exposure time 10 s. Human fibroblasts growing in a monolayer on a cover slide were exposed to microwave electromagnetic radiation. The layer of medium that covered cells during microwave exposure was about 1 mm thick. Cells were stained immediately after irradiation by 2% (w/v) orcein solution in 45% (w/v) acetic acid. Experiments were made at room temperature (25 °C), and control cell samples were processed in the same conditions. We assessed heterochromatin granule quantity (HGQ) at 600× magnification. Microwave irradiation at the intensity of 1 μW/cm2 produced no effect, and irradiation at the intensities of 10 and 100 μW/cm2 induced an increase in HGQ. More intense irradiation induced more chromatin condensation. The right-handed elliptically polarized radiation revealed more biological activity than the left-handed polarized one.  相似文献   
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OBJECTIVE: To report on the backgrounds and physical and emotional well-being of street children using two street shelters in Kyiv, Ukraine. This study is important because personal accounts of street children may highlight individual or family factors that are associated with vulnerability for and risk of poor mental health, and these could have serious repercussions for the future. This study also poses a challenge to research because street children are a highly elusive population that services find hard to reach. METHODS: Ninety-seven children were recruited and interviewed using a semistructured, psychosocial interview schedule; psychopathology was measured using the Strengths and Difficulties Questionnaire (SDQ) and the Mood and Feelings Questionnaire (MFQ). RESULTS: Seventy percent of street children scored for behavioral and emotional difficulties on the SDQ, and 74% scored for depression on the MFQ. Current health problems were reported by 78%, with 43% described as persistent or severe. Two thirds of the children in this sample were not homeless but had chosen life on the streets in preference to permanent residence with their families. Their "survival" history on the streets contributed to the development of three different profiles of vulnerability. CONCLUSIONS: High rates of physical and emotional problems in a population of street children, many of whom were still connected to their families, emphasize the importance of developing different approaches for children with different vulnerabilities. This study also demonstrates the feasibility of embedding on-going field research into the service dimension of "front-line" social care agencies.  相似文献   
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This study investigated the use of automated essay scoring (AES) to identify at-risk students enrolled in a first-year university writing course. An application of AES, the Criterion® Online Writing Evaluation Service was evaluated through a methodology focusing on construct modelling, response processes, disaggregation, extrapolation, generalization, and consequence. Based on the results of our two-year study with students (N = 1,482) at a public technological research university in the United States, we found that Criterion offered a defined writing construct congruent with established models, achieved acceptance among students and instructors, showed no statistically significant differences between ethnicity groups of sufficient sample size, correlated at acceptable levels with other writing measures, performed in a stable fashion, and enabled instructors to identify at-risk students to increase their course success.  相似文献   
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Collaborative-constructivist online learning appears well aligned with Ukraine’s post-revolutionary aspirations for globalised and transformed higher education. This study explores digital competencies of students and professors at Kyiv National Economic University, Ukraine, to probe readiness for fully online collaborative learning. The General Technology Competency and Use profile tool was completed by 244 participants to measure digital experience and confidence across four categories of human–computer activity. To assess readiness, reported levels of competencies were related to the three dimensions of successful collaborative learning described by the Community of Inquiry model. Despite some key differences between students and teachers, general findings include moderate-to-low levels of self-reported technical, social and informational competency, accompanied by consistently low levels of epistemological competency. These findings suggest that neither students nor teachers are adequately prepared for achieving high levels of social, cognitive and teaching presence in a fully online learning environment. It is recommended that digital-competency development become an educational priority.  相似文献   
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