4,081 research outputs found

    Writing Assignments with a Metacognitive Component Enhance Learning in a Large Introductory Biology Course

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    Writing assignments, including note taking and written recall, should enhance retention of knowledge, whereas analytical writing tasks with metacognitive aspects should enhance higher-order thinking. In this study, we assessed how certain writing-intensive “interventions,” such as written exam corrections and peer-reviewed writing assignments using Calibrated Peer Review and including a metacognitive component, improve student learning. We designed and tested the possible benefits of these approaches using control and experimental variables across and between our three-section introductory biology course. Based on assessment, students who corrected exam questions showed significant improvement on postexam assessment compared with their nonparticipating peers. Differences were also observed between students participating in written and discussion-based exercises. Students with low ACT scores benefited equally from written and discussion-based exam corrections, whereas students with midrange to high ACT scores benefited more from written than discussion-based exam corrections. Students scored higher on topics learned via peer-reviewed writing assignments relative to learning in an active classroom discussion or traditional lecture. However, students with low ACT scores (17–23) did not show the same benefit from peer-reviewed written essays as the other students. These changes offer significant student learning benefits with minimal additional effort by the instructors

    Residue analyses and exposure assessment of the Irish population to nitrofuran metabolites from different food commodities in 2009–2010

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    peer-reviewedAn exposure assessment to nitrofuran residues was performed for three human populations (adults, teenagers and children), based on residue analyses of foods of animal origin (liver, honey, eggs and aquaculture) covering the 2-year period 2009– 2010. The occurrence of nitrofuran metabolites in food on the Irish market was determined for the selected period using the data from Ireland’s National Food Residue Database (NFRD) and from results obtained from the analysis of retail samples (aquaculture and honey). Laboratory analyses of residues were performed by methods validated in accordance with Commission Decision 2002/657/EC regarding performance of the analytical method and interpretation of results. Semicarbazide (SEM) was the contaminant most frequently identified and its content ranged from 0.09 to 1.27 ÎŒg kg−1. SEM is currently used as a marker of nitrofuran abuse, but it may also occur from other sources. The presence of nitrofuran metabolite 3-amino-2-oxazolidinone (AOZ) was detected in two aquaculture samples (prawns) at 1.63 and 1.14 ÎŒg kg−1, but such a low number of positive cases did not present sufficient data for a full AOZ exposure assessment. Therefore, the evaluation of exposure was focused on SEM-containing food groups only. Exposure assessments were completed using a probabilistic approach that generated 10 iterations. The results of both the upper- and lower-bound exposure assessments demonstrate that SEM exposure for Irish adults, teenagers and children from selected food commodities are well below EFSA-estimated safe levels.This research was funded by the Food for Health Research Initiative (FHRI) administered by the Irish Department of Agriculture, Food and the Marine and the Health Research Board (Contract 07FHRIAFRC5

    Soil CO2 Emissions Associated with Termitaria in Tropical Savanna: Evidence for Hot-Spot Compensation

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    Our understanding of carbon (C) dynamics within savannas is very limited, especially how source/sink dynamics are influenced by the resident biota. Previous measurements of epigeal termite mounds (termitaria), ubiquitous in many savannas, have shown that they are considerable point sources of soil carbon dioxide (CO2), whereas CO2 measurements collected outside the mounds were generally assumed to be independent of termite activity. However, no measurements were conducted along gradients away from the mounds to confirm this. We quantified daytime soil CO2 emissions (soil respiration) along gradients from the center to 20m from the mound edge in Serengeti National Park, and measured soil temperature/moisture, macro-invertebrate abundance, and vegetation height as variables potentially influencing these emissions. Further, we quantified how far into the savanna termitaria impact CO2 emissions. As in other studies, we found the highest soil CO2 fluxes at the termitaria-center and considerably lower fluxes in the surrounding savanna. Macro-invertebrate abundance was associated with the differences in emissions measured, whereas the other variables were not. The analysis of spatial autocorrelation revealed significantly lower fluxes between the termitaria edge and up to 9m from the edge compared to the values measured at the termitaria-center and between 10 and 20m from the termitaria edge. When extrapolating the emissions across the landscape our results suggest that the lower CO2 emissions found between the edge and 9m fully compensate for the high fluxes measured at the termitaria center. Consequently, our findings provide evidence that termitaria might influence the savanna C source-sink dynamics differently than previously though

    Effects of grazing and soil micro-climate on decomposition rates in a spatio-temporally heterogeneous grassland

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    Grazing and seasonal variation in precipitation and temperature are important controls of soil and plant processes in grasslands. As these ecosystems store up to 30% of the world's belowground carbon (C), it is important to understand how this variability affects mineral soil C pools/fluxes, and how C cycling might be affected by changes in precipitation and temperature, due to climate change. The aim of this study was to investigate the effects of grazing and differences in soil temperature and moisture on standard organic matter (OM) decomposition rates (cotton cloth) incubated in the top 10cm soil of grasslands with variable topography in Yellowstone National Park (YNP) during the 2004 growing season. Grazing did not affect soil temperature, moisture, cotton cloth decomposition rates, soil bulk density, soil C and N concentrations, or soil C:N ratios. However, a large spatio-temporal variability in decomposition was observed: cotton cloth decomposition was positively related to soil moisture and soil C and N concentrations, and negatively to soil temperature. Highest decomposition rates were found in wetter slope bottom soils [season averages of decomposition given as rate of decomposition (cotton rotting rate = CRR) = 23-26%] and lower rates in drier, hill-top soils (season averages, CRR = 20%). Significantly higher decomposition rates were recorded in spring, early summer and early fall when soils were moist and cool (spring, CRR = 25%; early summer, CRR = 26%; fall, CRR = 20%) compared to mid-summer (CRR = 18%) when soils were dry and warm. Our findings suggest that climate-change related decreases in precipitation and increases in temperature predicted for North American grasslands would decrease soil OM decomposition in YNP, which contrasts the general assumption that increases in temperature would accelerate OM decomposition rate

    Exploring Effective Professional Development Strategies for In-Service Teachers on Guiding Beginning Readers to Become More Metacognitive in Their Oral Reading

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    This case study explored professional development centered on explicit teaching strategies with in-service first-grade teachers as they engaged beginning readers to consider stronger self-awareness of their thinking processes as they read. In this paper, we report on how teacher beliefs shifted regarding the impact of explicit versus implicit instructional practices that increased their students’ metacognitive awareness and regulation. Teachers adopted specific instructional strategies over the course of the professional development that positively impacted their students’ achievement, including one teacher’s use of peer coaching. As teachers observed their students doing more than they thought they were capable of, their beliefs about beginning readers’ capabilities to selfmonitor their oral reading and explain their thinking processes increased, thus positively impacting the value they placed on the role of explicit metacognitive instruction in early literacy instruction. Our study demonstrated effective components of professional development include integrating reflective and collective reflection within a teacher-driven inquiry model

    EVENT STUDY : REAKSI PASAR MODAL SEBELUM DAN SESUDAH ADANYA COVID-19 (Studi Pada Perusahaan Non-Perbankan Yang Terdaftar Di BEI Sebagai Anggota LQ45)

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    This study aims to test whether there are differences in the average Abnormal Return and Trading Volume Activity before and after the Covid-19. The population in this study are companies listed on the LQ-45 Index. The sample used in this study is a non-banking company listed on the LQ-45 Index. The sampling technique used purposive sampling method. Data collection is done by documenting the required data on the capital market website. The data analysis technique used is the normality test using Kolmogorov-Smirnov and hypothesis testing using the Wilcoxon Signed rank test. The results of this study indicate that there are significant differences in the average abnormal return and trading volume activity before and after the presence of Covid-19. Which is addressed with a significant value <0.05

    Matrix metalloproteinase-13 refines pathological staging of precancerous colorectal lesions

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    An exact classification of precancerous stages of colorectal polyps might improve therapy and patientsÂŽ outcome. Here we investigate the association between grade of dysplasia and Matrix metalloproteinase-13 (MMP-13) expression in 137 biopsies from patients with cancerous and non-cancerous colorectal adenomas. A reproducible staining procedure for histologic MMP-13 analysis in routinely fixed colorectal biopsy specimens has been established. A newly adopted immunoreactive scoring system for MMP-13 was demonstrated as reliable readout. The strength of the association between pathologic stage and immunoreactive MMP-13 scoring emphasizes its eligibility for diagnosis in precancerous colorectal lesions

    The Calibration of the HST Kuiper Belt Object Search: Setting the Record Straight

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    The limiting magnitude of the HST data set used by Cochran et al. (1995) to detect small objects in the Kuiper belt is reevaluated, and the methods used are described in detail. It is shown, by implanting artificial objects in the original HST images, and re-reducing the images using our original algorithm, that the limiting magnitude of our images (as defined by the 50% detectability limit) is V=28.4V=28.4. This value is statistically the same as the value found in the original analysis. We find that ∌50\sim50% of the moving Kuiper belt objects with V=27.9V=27.9 are detected when trailing losses are included. In the same data in which these faint objects are detected, we find that the number of false detections brighter than V=28.8V=28.8 is less than one per WFPC2 image. We show that, primarily due to a zero-point calibration error, but partly due to inadequacies in modeling the HST'S data noise characteristics and Cochran et al.'s reduction techniques, Brown et al. 1997 underestimate the SNR of objects in the HST dataset by over a factor of 2, and their conclusions are therefore invalid.Comment: Accepted to ApJ Letters; 10 pages plus 3 figures, LaTe

    Satellite radar altimetry over ice. Volume 1: Processing and corrections of Seasat data over Greenland

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    The data-processing methods and ice data products derived from Seasat radar altimeter measurements over the Greenland ice sheet and surrounding sea ice are documented. The corrections derived and applied to the Seasat radar altimeter data over ice are described in detail, including the editing and retracking algorithm to correct for height errors caused by lags in the automatic range tracking circuit. The methods for radial adjustment of the orbits and estimation of the slope-induced errors are given
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