6,453 research outputs found

    GRAIN EXPORTS AS A SOURCE OF AGRICULTURAL INSTABILITY

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    International Relations/Trade,

    Blending Formative and Summative Assessment in a Capstone Subject: ‘It’s not your tools, it’s how you use them’

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    Discussions about the relationships between formative and summative assessment have come full circle after decades of debate. For some time formative assessment with its emphasis on feedback to students was promoted as better practice than traditional summative assessment. Summative assessment practices were broadly criticised as distanced from the learning process. More recently discussions have refocused on the potential complementary characteristics of formative and summative purposes of assessment. However studies on practical designs to link formative and summative assessment in constructive ways are rare. In paramedic education, like many other professional disciplines, strong traditions of summative assessment - assessment ‘of’ learning - have long dominated. Communities require that a graduate has been judged fit to practice. The assessment redesign described and evaluated in this paper sought to rebalance assessment relationships in a capstone paramedic subject to integrate formative assessment for learning with summative assessment of learning. Assessment was repositioned as a communication process about learning. Through a variety of frequent assessment events, judgement of student performance is accompanied with rich feedback. Each assessment event provides information about learning, unique to each student’s needs. Each assessment event shaped subsequent assessment events. Student participants in the formal evaluation of the subject indicated high levels of perceived value and effectiveness on learning across each of the assessment events, with broad agreement also demonstrated relating to student perceptions for preparedness: ‘readiness to practice’. Our approach focused on linking assessment events, resulted in assessments providing formative communication to students and summative outcome information to others simultaneously. The formative-summative dichotomy disappeared: all assessment became part of communication about learning

    Endocytic Sorting and Downregulation of the M2 Acetylcholine Receptor is Regulated by Ubiquitin and the ESCRT Complex

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    Acknowledgements The authors would like to thank Professor Mark von Zastrow from the University of California, San Francisco for sharing critical constructs. We would like to thank Kevin MacKenzie and the University of Aberdeen Microscopy core and the Iain Fraser Flow cytometry core for their assistance in the acquisition of data, and Professor Lynda Erskine for critical reading of the manuscript. This work was supported by a PhD studentship from the University of Aberdeen (DZ) and by funding from the Royal Society and Tenovus Scotland (JNH)Peer reviewedPostprin

    Lack of an Interchromosomal Effect Associated with Spontaneous Recombination in Males of Drosophila Melanogaster

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    Author Institution: Department of Biological Sciences, Bowling Green State UniversityIt is shown that the frequency of spontaneous male recombination in two different lines of Drosophila melanogaster (OKI and T-007) are not subject to an interchromosomal effect. Second-chromosome male recombination in these lines was not affected by heterozygosity for the multiple third-chromosome inversions In(3LR)TM3 or In(3LR)Ubxm, which do affect recombination in females. It seems, therefore, that a large fraction of spontaneous recombination in males of D. melanogaster occurs by some mechanism other than that in females. We discuss the possibility that the mechanism is chromosome breakage and reunion, and that these breakage events may be caused by a microorganism

    Analysis of gene number and development in polygenic systems : (polygenes, variation, selection, pattern)

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    The assumption that quantitative variation is produced by a large number of genes is re-examined. In fact, one finds that often only a small number of loci are involved. This, therefore, opens to careful study the developmental effects associated with polygenic variation.JAMES N. THOMPSON, JR., Department of Zoology, University of Oklahoma, Norman, Oklahoma

    Optimal Investment to Enable Evolutionary Rescue

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    'Evolutionary rescue' is the potential for evolution to enable population persistence in a changing environment. Even with eventual rescue, evolutionary time lags can cause the population size to temporarily fall below a threshold susceptible to extinction. To reduce extinction risk given human-driven global change, conservation management can enhance populations through actions such as captive breeding. To quantify the optimal timing of, and indicators for engaging in, investment in temporary enhancement to enable evolutionary rescue, we construct a model of coupled demographic-genetic dynamics given a moving optimum. We assume 'decelerating change', as might be relevant to climate change, where the rate of environmental change initially exceeds a rate where evolutionary rescue is possible, but eventually slows. We analyze the optimal control path of an intervention to avoid the population size falling below a threshold susceptible to extinction, minimizing costs. We find that the optimal path of intervention initially increases as the population declines, then declines and ceases when the population growth rate becomes positive, which lags the stabilization in environmental change. In other words, the optimal strategy involves increasing investment even in the face of a declining population, and positive population growth could serve as a signal to end the intervention. In addition, a greater carrying capacity relative to the initial population size decreases the optimal intervention. Therefore, a one-time action to increase carrying capacity, such as habitat restoration, can reduce the amount and duration of longer-term investment in population enhancement, even if the population is initially lower than and declining away from the new carrying capacity

    The SDO/EVE Solar Irradiance Coronal Dimming Index Catalog. I. Methods and Algorithms

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    When a coronal mass ejection departs, it leaves behind a temporary void. That void is known as coronal dimming, and it contains information about the mass ejection that caused it. Other physical processes can cause parts of the corona to have transient dimmings, but mass ejections are particularly interesting because of their influence in space weather. Prior work has established that dimmings are detectable even in disk-integrated irradiance observations, i.e., Sun-as-a-star measurements. The present work evaluates four years of continuous Solar Dynamics Observatory Extreme Ultraviolet Experiment (EVE) observations to greatly expand the number of dimmings we may detect and characterize, and collects that information into Jamess EVE Dimming Index catalog. This paper details the algorithms used to produce the catalog, provides statistics on it, and compares it with prior work. The catalog contains 5051 potential events (rows), which correspond to all robustly detected solar eruptive events in this time period as defined by >C1 flares. Each row has a corresponding 27,349 elements of metadata and parameterizations (columns). In total, this catalog is the result of analyzing 7.6 million solar ultraviolet light curves

    Continuum removal in H\alpha\ extragalactic measurements

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    We point out an important source of error in measurements of extragalactic H-alpha emission and suggest ways to reduce it. The H-alpha line, used for estimating star formation rates, is commonly measured by imaging in a narrow band and a wide band, both which include the line. The image analysis relies on the accurate removal of the underlying continuum. We discuss in detail the derivation of the emission line's equivalent width and flux for extragalactic extended sources, and the required photometric calibrations. We describe commonly used continuum-subtraction procedures, and discuss the uncertainties that they introduce. Specifically, we analyse errors introduced by colour effects. We show that the errors in the measured H-alpha equivalent width induced by colour effects can lead to underestimates as large as 40% and overestimates as large as 10%, depending on the underlying galaxy's stellar population and the continuum-subtraction procedure used. We also show that these errors may lead to biases in results of surveys, and to the underestimation of the cosmic star formation rate at low redshifts (the low z points in the Madau plot). We suggest a method to significantly reduce these errors using a single colour measurement.Comment: 8 pages, 3 figures, MNRAS in pres
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