312 research outputs found

    Effects of video feedback mode on students' academic writing

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    Academic writing is a challenge for students undertaking a degree as they encounter new genres in reading and writing, a new academic register, and referencing. Many researchers have highlighted the importance of feedback for developing students’ academic writing (e.g., K. Hyland, 2009; Poulos & Mahony, 2008), yet others have shown that feedback is often poor quality or not engaged with by students (Chanock, 2000; Wingate, 2010). Researchers have theorised that the mode of feedback may affect feedback provision and students’ engagement with feedback (Crook et al., 2012; Kerr & McLaughlin, 2008; Stannard, 2008); however, there is little empirical research that investigates the effects of feedback mode. To address this research gap, this study examines the effect of two different feedback modes, written mode and audio-visual mode, with particular attention to the focus and form of the feedback, as well as students’ revisions in response to the feedback. A mixed method case study design was employed with a purposeful sample of 20 first-year undergraduate students at an Australian higher education institution. Over the course of a term, each student submitted two draft assignments to an academic skills advisor for feedback. One paper received written feedback and the other paper received screen-capture audio-visual feedback, which incorporates spoken recorded feedback and simultaneous video of the advisor’s computer screen. Using grounded theory methods, the analysis involved coding, classifying and organising the advisor’s comments (n = 1040) and the students’ corresponding revisions into an analytical framework to measure and describe the effects of mode on the provision and uptake of feedback. This inductive approach is in the tradition of feedback researchers such as Ferris (1997, 2006) and Merry and Orsmond (2008), but the current study’s framework differs from others as it incorporates a sociocultural theoretical perspective and moves away from viewing comments as corrective feedback in response to language errors only. The student participants were also surveyed and interviewed to gain qualitative data about their perceptions and preferences to help explain the findings of the feedback analysis. The analysis revealed that 88% of the video comments led students to make a successful revision to their draft compared to 77% of the written comments. Results show further that written feedback was highly directive and largely focused on linguistic accuracy, whereas video feedback was more likely to address content and text structure issues and contain detailed explanations and praise. Most student stated they prefer video feedback because, in their opinion, it is easier to understand, feels more personal and includes explanations about why changes are necessary and how to improve their work. These findings indicate that the spoken nature of audio-visual feedback can help implement feedback good practice principles, such as those suggested by Nicol and Macfarlane-Dick (2006) and Straub (2000), and can also facilitate feedback that aligns with a Vygotskian theoretical orientation (Vygotsky, 1978) to academic language and learning support. The findings also support Mayer’s (2009) claim that a multimodal (e.g. audio and visual) approach to learning is more effective than a mono-modal (e.g. only visual) approach. These insights contribute to the growing body of literature on feedback methods and can inform feedback practice in higher education to support students with the development of their academic writing skills

    Within-canopy experimental leaf warming induces photosynthetic decline instead of acclimation in two northern hardwood species

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    Northern hardwood forests are experiencing higher temperatures and more extreme heat waves, potentially altering plant physiological processes. We implemented in-situ leaf-level warming along a vertical gradient within a mature forest canopy to investigate photosynthetic acclimation potential of two northern hardwood species, Acer saccharum and Tilia americana. After 7 days of +3°C warming, photosynthetic acclimation was assessed by measuring differences between heated and control photosynthetic rates (Aopt) at leaf optimum temperatures (Topt). We also measured the effects of warming and height on maximum rates of Rubisco carboxylation, stomatal conductance, transpiration, and leaf traits: leaf area, leaf mass per area, leaf nitrogen, and leaf water content. We found no evidence of photosynthetic acclimation for either species, but rather Aopt declined with warming overall. We found slight shifts in LMA and Narea, leaf traits associated with photosynthetic capacity, after 1 week of experimental warming. T. americana LMA and Narea was lower in the upper canopy heated leaves than in the control leaves, contributing a shift in Narea height distribution in the heated leaves. T. americana showed evidence of greater resiliency to warming, with greater thermoregulation, physiological plasticity, and evapotranspiration. As expected, Aopt of A. saccharum increased with height, but Aopt of T. americana was highest in the sub canopy, possibly due to constraints on leaf water balance and photosynthetic capacity in the upper canopy. Thus, models relying on canopy height or light environment may incorrectly estimate vertical variation of photosynthetic capacity. If these species are not able to acclimate to warmer temperatures, we could see alteration of plant carbon balance of these two key northern hardwood species

    Can a professional development workshop with follow-up alter practitioner behaviour and outcomes for neck pain patients? A randomised controlled trial

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    Background: Continuing professional development (CPD) is a fundamental component of physiotherapy practice. Follow-up sessions provide opportunity for the refinement of skills developed during CPD workshops. However, it is necessary to identify if such opportunity translates to improved physiotherapist performance and patient outcomes

    COMPRESSIVE BEHAVIOR OF CONCRETE COLUMNS AXIALLYLOADED BEFORE CFRP-WRAPPING. REMARKS BY EXPERIMENTALNUMERICAL INVESTIGATION

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    Strengthening of existing concrete columns with Fiber Reinforced Polymers (FRP) results generally in a satisfactory structural member improvement in terms of load and strain capacity. A reliable prediction of the capacity obtained by these reinforcement strategies requests a proper knowledge of the load-strain response of the confined concrete elements. However, so far, the available design methods and technical codes do not consider the effect of the possible presence of service loads at the moment of application of the reinforcement, and therefore, the compressive behavior of the concrete confined under preload is still unclear. In this paper, the effect of sustained loads on the compressive behavior of concrete columns CFRP-confined while preloaded is analyzed. Experimental tests were performed on circular concrete columns confined under low, medium and high preload levels before wrapping ad subsequently loaded until failure, observing the differences respect to the standard compressive stress-strain response of FRP-confined concrete. A finite element (FE) model is also developed by using ABAQUS software to simulate the physical scheme of the experimental tests. The accuracy of the model is validated through comparing with the experimental results

    Strategies for Waste Recycling: The Mechanical Performance of Concrete Based on Limestone and Plastic Waste

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    Recycling is among the best management strategies to avoid dispersion of several types of wastes in the environment. Research in recycling strategies is gaining increased importance in view of Circular Economy principles. The exploitation of waste, or byproducts, as alternative aggregate in concrete, results in a reduction in the exploitation of scarce natural resources. On the other hand, a productive use of waste leads to a reduction in the landfilling of waste material through the transformation of waste into a resource. In this frame of reference, the paper discusses how to use concrete as a container of waste focusing on the waste produced in limestone quarries and taking the challenge of introducing plastic waste into ordinary concrete mixes. To prove the possibility of reaching this objective with acceptable loss of performance, the mechanical characteristics of concrete mixed with additional alternative aggregates classified as waste are investigated and dis-cussed in this paper through the presentation of two experimental campaigns. The first experimental investigation refers to concrete made with fine limestone waste used as a replacement for fine aggregate (sand), while the second experimental program refers to the inclusion of three types of plastic wastes in the concrete. Different mixes with different percentages of wastes are investigated to identify possible fields of application. The experimental results indicate that use of limestone quarry waste and use of plastic waste are possible within significant percentage ranges, having recognized a limited reduction of concrete strength that makes concrete itself appropriate for different practical applications

    Alternate trait-based leaf respiration schemes evaluated at ecosystem-scale through carbon optimization modeling and canopy property data

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    Leaf maintenance respiration (Rleaf,m) is a major but poorly understood component of the terrestrial carbon cycle (C). Earth systems models (ESMs) use simple sub‐models relating Rleaf,m to leaf traits, applied at canopy scale. Rleaf,m models vary depending on which leaf N traits they incorporate (e.g., mass or area based) and the form of relationship (linear or nonlinear). To simulate vegetation responses to global change, some ESMs include ecological optimization to identify canopy structures that maximize net C accumulation. However, the implications for optimization of using alternate leaf‐scale empirical Rleaf,m models are undetermined. Here we combine alternate well‐known empirical models of Rleaf,m with a process model of canopy photosynthesis. We quantify how net canopy exports of C vary with leaf area index (LAI) and total canopy N (TCN). Using data from tropical and arctic canopies, we show that estimates of canopy Rleaf,m vary widely among the three models. Using an optimization framework, we show that the LAI and TCN values maximizing C export depends strongly on the Rleaf,m model used. No single model could match observed arctic and tropical LAI‐TCN patterns with predictions of optimal LAI‐TCN. We recommend caution in using leaf‐scale empirical models for components of ESMs at canopy‐scale. Rleaf,m models may produce reasonable results for a specified LAI, but, due to their varied representations of Rleaf,mfoliar N sensitivity, are associated with different and potentially unrealistic optimization dynamics at canopy scale. We recommend ESMs to be evaluated using response surfaces of canopy C export in LAI‐TCN space to understand and mitigate these risks

    Photosynthetic and Respiratory Acclimation of Understory Shrubs in Response to in situ Experimental Warming of a Wet Tropical Forest

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    Despite the importance of tropical forests to global carbon balance, our understanding of how tropical plant physiology will respond to climate warming is limited. In addition, the contribution of tropical forest understories to global carbon cycling is predicted to increase with rising temperatures, however, in situ warming studies of tropical forest plants to date focus only on upper canopies. We present results of an in situ field-scale +4°C understory infrared warming experiment in Puerto Rico (Tropical Responses to Altered Climate Experiment; TRACE). We investigated gas exchange responses of two common understory shrubs, Psychotria brachiata and Piper glabrescens, after exposure to 4 and 8 months warming. We assessed physiological acclimation in two ways: (1) by comparing plot-level physiological responses in heated versus control treatments before and after warming, and (2) by examining physiological responses of individual plants to variation in environmental drivers across all plots, seasons, and treatments. P. brachiata has the capacity to up-regulate (i.e., acclimate) photosynthesis through broadened thermal niche and up-regulation of photosynthetic temperature optimum (Topt) with warmer temperatures. P. glabrescens, however, did not upregulate any photosynthetic parameter, but rather experienced declines in the rate of photosynthesis at the optimum temperature (Aopt), corresponding with lower stomatal conductance under warmer daily temperatures. Contrary to expectation, neither species showed strong evidence for respiratory acclimation. P. brachiata down-regulated basal respiration with warmer daily temperatures during the drier winter months only. P. glabrescens showed no evidence of respiratory acclimation. Unexpectedly, soil moisture, was the strongest environmental driver of daily physiological temperature responses, not vegetation temperature. Topt increased, while photosynthesis and basal respiration declined as soils dried, suggesting that drier conditions negatively affected carbon uptake for both species. Overall, P. brachiata, an early successional shrub, showed higher acclimation potential to daily temperature variations, potentially mitigating negative effects of chronic warming. The negative photosynthetic response to warming experienced by P. glabrescens, a mid-successional shrub, suggests that this species may not be able to as successfully tolerate future, warmer temperatures. These results highlight the importance of considering species when assessing climate change and relay the importance of soil moisture on plant function in large-scale warming experiments

    Predicting effects of climate change on productivity and persistence of forest trees

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    Global climate change increases uncertainty in sustained functioning of forest ecosystems. Forest canopies are a key link between terrestrial ecosystems, the atmosphere, and climate. Here, we introduce research presented at the 66th meeting of the Ecological Society of Japan in the symposium “Structure and function of forest canopies under climate change.” Old-growth forest carbon stores are the largest and may be the most vulnerable to climate change as the balance between sequestration and emission could easily be tipped. Detailed structural analysis of individual large, old trees shows they are allocating wood to the trunk and crown in patterns that cannot be deduced from ground, thus can be used to more accurately quantify total forest carbon and sequestration. Slowly migrating species sensitive to novel climatic conditions will have to acclimate at the individual level. Accounting for physiological responses of trees to climate change will improve predictions of future species distributions and subsequent functioning of forest ecosystems. Field experiments manipulating temperature and precipitation show how trees compensate physiologically to mitigate for higher temperatures and drought. However, it is difficult to measure acclimation responses over long timeframes. Intraindividual trait variation is proposed as an indicator of acclimation potential of trees to future conditions and suggests that acclimation potential may vary among regional populations within a species. Integrating whole-tree structural data with physiological data offers a promising avenue for understanding how trees will respond to climatic shifts
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