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Effects of a simulated Martian UV flux on the cyanobacterium, Chroococcidiopsis sp. 029

first_imgDried monolayers of Chroococcidiopsis sp. 029, a desiccation-tolerant, endolithic cyanobacterium, were exposed to a simulated martian-surface UV and visible light flux, which may also approximate to the worst-case scenario for the Archean Earth. After 5 min, there was a 99% loss of cell viability, and there were no survivors after 30 min. However, this survival was approximately 10 times higher than that previously reported for Bacillus subtilis. We show that under 1 mm of rock, Chroococcidiopsis sp. could survive (and potentially grow) under the high martian UV flux if water and nutrient requirements for growth were met. In isolated cells, phycobilisomes and esterases remained intact hours after viability was lost. Esterase activity was reduced by 99% after a 1-h exposure, while 99% loss of autofluorescence required a 4-h exposure. However, cell morphology was not changed, and DNA was still detectable by 4′,6-diamidino-2-phenylindole staining after an 8-h exposure (equivalent to approximately 1 day on Mars at the equator). Under 1 mm of simulant martian soil or gneiss, the effect of UV radiation could not be detected on esterase activity or autofluorescence after 4 h. These results show that under the intense martian UV flux the morphological signatures of life can persist even after viability, enzymatic activity, and pigmentation have been destroyed. Finally, the global dispersal of viable, isolated cells of even this desiccation-tolerant, ionizing-radiation-resistant microorganism on Mars is unlikely as they are killed quickly by unattenuated UV radiation when in a desiccated state. These findings have implications for the survival of diverse microbial contaminants dispersed during the course of human exploratory class missions on the surface of Mars.last_img read more

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News story: Modular versus linear GCSEs: does the structure of exams matter?

first_imgTeachers and education leaders will discuss the findings at an event in London today that will further understanding of the effect of assessment structure and policy on students in England. The research will be published shortly after today’s event has concluded.Dr Michelle Meadows, Executive Director for Strategy, Research and Risk, Ofqual, said: Our findings have been really surprising in a number of ways. We might have expected to see that modular examinations were easier, or at least easier for some of the groups we investigated, but we found no such differences. The comparable outcomes approach to setting standards has played a key role in this. Professor Jo-Anne Baird, Professor of Educational Assessment, University of Oxford, said: Overall, the literature review points to claims that linear exams favour longer-term retention of information and deep learning, whereas modular exams allow regular feedback on performance which can be motivating for some students. However, reflecting a number of caveats, the quantitative evidence suggests that modular and linear GCSEs lead to similar outcomes overall. The research did not support claims that modular or linear exams tend to favour male or female students, or affect the outcomes of low and high socio-economic status students differently. During interviews conducted between April and November 2015, and again in May 2017 following the introduction of the first reformed GCSEs, many teachers reflected positively that student performance could be assessed with greater fairness and validity through linear GCSEs. Teachers had mixed views on the subject of stress. Some expressed concerns about the potential impact of linearity on the wellbeing of those students who require additional support, others noted that the elimination of the continual testing associated with modular GCSEs may reduce stress for some students.center_img Teachers were concerned about the change to linear GCSEs when we spoke to them before the recent reforms. How they adapted during the period of this research has been impressive. We have been able to look at the effects of the changes on teachers’ practices and many can see benefits to the introduction of linear examinations. They also report that they would now like a period of stability. Ofqual and Oxford University’s Centre for Educational Assessment are today (Monday 29 April) publishing the findings of a 3-year joint research project on the impact of modular and linear exam structures at GCSE.Academics and researchers from both organisations collaborated on the project, Examination Reform: The Impact of Linear and Modular Examinations at GCSE. The research considers whether change in the structure of GCSE exams has affected standards, fairness, teaching and learning practices, cost, and students themselves. The project included a systematic review of existing literature on the advantages and disadvantages of modular and linear structures; extensive analysis of GCSE outcomes between 2007 and 2014, focusing on English, maths and science; and research into teachers’ views.The research is part of Ofqual’s ongoing work to ensure that exam reforms are operating well for the young people who take them. In summary, we conclude from the range of evidence gathered, that in the current educational context, linear exams are more suitable at GCSE than modular exams. In particular:last_img read more

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‘Coats for Kids’ kicks off in Franklin County this weekend

first_imgBrookville, In. — The United Way of Franklin County is collecting “Coats for Kids” this year through the 12th Man Club. Organizers plan to kick off the effort this Friday during the homecoming matchup between Franklin County High School and South Dearborn High School.Until October 31 coat donations can be dropped off at First Financial Bank, George’s Pharmacy and Jim True Ford. Preferred sizes are 5 to 16.last_img