33 research outputs found

    Content analysis of instructor tools for building a learning community

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    This work presents a content analysis of an online discussion forum accompanying a face-to-face introductory physics course. Content analysis is a quantitative method for analyzing text that uses a coding scheme to gain insight into student discussions. We explore the effects of "anchor" tasks, small weekly activities to help students engage with each other. The goal of this analysis was to examine how the distributions of codes are impacted by anchor versus non-anchor tasks, and different types of anchors. The result of this work was that the coding scheme was able to detect some differences between anchor and non-anchor threads, but further work should be done to observe behaviors that would require a more in-depth analysis of the text. This research is significant for physics education research (PER) because there is little PER using content analysis or studying online talk. This is a step towards identifying patterns in conversations between physics students and the tools that may help them have on topic conversations essential for their learning. Identifying such tools can aid instructors in creating effective online learning environments, and this project introduces "anchor" tasks as instructor tools for building a learning community

    Quantifying the linguistic persistence of high and low performers in an online student forum

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    This work uses recurrence quantification analysis (RQA) to analyze the online forum discussion between students in an introductory physics course. Previous network and content analysis found differences in student conversations occurring between semesters of data from an introductory physics course; this led us to probe which concepts occur and persist within conversations. RQA is a dynamical systems technique to map the number and structure of repetitions for a time series. We treat the transcript of forum conversations as a time series to investigate and apply RQA techniques to it. We characterize the forum behaviors of high and low scoring students, such as their percentage of recurring topics and persistence of discussing a topic over time. We quantify how high scoring and low scoring students use online discussion forum and test whether different patterns exist for these groups. This work is the first adaptation of recurrence quantification methods from the field of psychology for physics education research. Using RQA, there was not a general, observable difference in how the two different groups, high- and low-scoring students, used the forum; however, there were differences when focusing in on and comparing one high-scoring student and one low-scoring student. This technique has the potential for analyzing other PER data such as interviews or student discussions

    Avoiding Costly Conservation Mistakes: The Importance of Defining Actions and Costs in Spatial Priority Setting

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    Background: The typical mandate in conservation planning is to identify areas that represent biodiversity targets within the smallest possible area of land or sea, despite the fact that area may be a poor surrogate for the cost of many conservation actions. It is also common for priorities for conservation investment to be identified without regard to the particular conservation action that will be implemented. This demonstrates inadequate problem specification and may lead to inefficiency: the cost of alternative conservation actions can differ throughout a landscape, and may result in dissimilar conservation priorities

    Somatosensory processing in neurodevelopmental disorders

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    The purpose of this article is to review the role of somatosensory perception in typical development, its aberration in a range of neurodevelopmental disorders, and the potential relations between tactile processing abnormalities and central features of each disorder such as motor, communication, and social development. Neurodevelopmental disorders that represent a range of symptoms and etiologies, and for which multiple peer-reviewed articles on somatosensory differences have been published, were chosen to include in the review. Relevant studies in animal models, as well as conditions of early sensory deprivation, are also included. Somatosensory processing plays an important, yet often overlooked, role in typical development and is aberrant in various neurodevelopmental disorders. This is demonstrated in studies of behavior, sensory thresholds, neuroanatomy, and neurophysiology in samples of children with Fragile X syndrome, autism spectrum disorders (ASD), attention deficit hyperactivity disorder (ADHD), and cerebral palsy (CP). Impaired somatosensory processing is found in a range of neurodevelopmental disorders and is associated with deficits in communication, motor ability, and social skills in these disorders. Given the central role of touch in early development, both experimental and clinical approaches should take into consideration the role of somatosensory processing in the etiology and treatment of neurodevelopmental disorders

    The Effect of Carbon Credits on Savanna Land Management and Priorities for Biodiversity Conservation

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    Carbon finance offers the potential to change land management and conservation planning priorities. We develop a novel approach to planning for improved land management to conserve biodiversity while utilizing potential revenue from carbon biosequestration. We apply our approach in northern Australia's tropical savanna, a region of global significance for biodiversity and carbon storage, both of which are threatened by current fire and grazing regimes. Our approach aims to identify priority locations for protecting species and vegetation communities by retaining existing vegetation and managing fire and grazing regimes at a minimum cost. We explore the impact of accounting for potential carbon revenue (using a carbon price of US14pertonneofcarbondioxideequivalent)onpriorityareasforconservationandtheimpactofexplicitlyprotectingcarbonstocksinadditiontobiodiversity.OurresultsshowthatimprovedmanagementcanpotentiallyraiseapproximatelyUS14 per tonne of carbon dioxide equivalent) on priority areas for conservation and the impact of explicitly protecting carbon stocks in addition to biodiversity. Our results show that improved management can potentially raise approximately US5 per hectare per year in carbon revenue and prevent the release of 1–2 billion tonnes of carbon dioxide equivalent over approximately 90 years. This revenue could be used to reduce the costs of improved land management by three quarters or double the number of biodiversity targets achieved and meet carbon storage targets for the same cost. These results are based on generalised cost and carbon data; more comprehensive applications will rely on fine scale, site-specific data and a supportive policy environment. Our research illustrates that the duel objective of conserving biodiversity and reducing the release of greenhouse gases offers important opportunities for cost-effective land management investments

    Content analysis of instructor tools for building a learning community

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    This work presents a content analysis of an online discussion forum accompanying a face-to-face introductory physics course. Content analysis is a quantitative method for analyzing text that uses a coding scheme to gain insight into student discussions. We explore the effects of "anchor" tasks, small weekly activities to help students engage with each other. The goal of this analysis was to examine how the distributions of codes are impacted by anchor versus non-anchor tasks, and different types of anchors. The result of this work was that the coding scheme was able to detect some differences between anchor and non-anchor threads, but further work should be done to observe behaviors that would require a more in-depth analysis of the text. This research is significant for physics education research (PER) because there is little PER using content analysis or studying online talk. This is a step towards identifying patterns in conversations between physics students and the tools that may help them have on topic conversations essential for their learning. Identifying such tools can aid instructors in creating effective online learning environments, and this project introduces "anchor" tasks as instructor tools for building a learning community

    Identifying Caregivers in Primary Care to Influence Keeping Elderly Patients in the Home

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    There are many barriers present to keeping elderly in the home . One of these barriers is lack of identifying and supporting caregivers of these patients . Informal caregivers provide the majority of care for elderly patients residing in the community . Being able to identify and support these caregivers in the primary care setting may prevent caregiver burden, with a primary goal of keeping the care recipient in the home . This interactive presentation objectives include; exploring the influences of the caregiver role and the elderly’s ability to stay in the home, critiquing the existing evidence for identifying caregivers of elderly patients and introducing and describing ongoing research within a Tennessee Primary Care Practice

    The Nature Conservancy

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    Global biodiversity is in decline. This is of concern for aesthetic and ethical reasons, but possibly also for practical reasons, as suggested by experimental studies, mostly with plants, showing that biodiversity reductions in small study plots can lead to compromised ecosystem function. However, inferring that ecosystem functions will decline due to biodiversity loss in the real world rests on the untested assumption that such loss is actually occurring at these small scales in nature. Using a global database of 168 published studies and >16,000 nonexperimental, local-scale vegetation plots, we show that mean temporal change in species diversity over periods of 5-261 y is not different from zero, with increases at least as likely as declines over time. Sites influenced primarily by plant species' invasions showed a tendency for declines in species richness, whereas sites undergoing postdisturbance succession showed increases in richness over time. Other distinctions among studies had little influence on temporal richness trends. Although maximizing diversity is likely important for maintaining ecosystem function in intensely managed systems such as restored grasslands or tree plantations, the clear lack of any general tendency for plant biodiversity to decline at small scales in nature directly contradicts the key assumption linking experimental results to ecosystem function as a motivation for biodiversity conservation in nature. How often real world changes in the diversity and composition of plant communities at the local scale cause ecosystem function to deteriorate, or actually to improve, remains unknown and is in critical need of further study. spatial scale | permanent plots | ecosystem services A huge number of experiments has investigated the effects of species diversity (typically the number of species) on ecosystem function in small study plots (≤400 m 2 ), with a general consensus emerging that processes such as primary productivity and nutrient uptake increase as a function of the number of species in a community (1-6). These experiments thus appear to provide a powerful motivation for biodiversity conservation, given that ecosystem functions underpin many ecosystem services from which people benefit, such as forage production and carbon sequestration (1). However, the link between diversityfunction experiments and the widespread argument that ecosystem function should motivate biodiversity conservation (7-11) hinges on the untested assumption that global biodiversity declines apply to the small scale (2). Experimental studies typically focus on small spatial scales not only for practical reasons, but also because organisms, plants in particular, typically interact over short distances (12), and so it is at the small scale that biodiversity is most likely to have an important impact on the functioning of ecosystems (13)(14)(15). Habitat loss, invasive species, and overexploitation, among other factors, have accelerated global species' extinction well beyond the background rate (16-18), and it is tempting to assume that a global decline in biodiversity is necessarily accompanied by declines at smaller spatial scales. However, this is not a logical inevitability because, unlike other key variables involved in global environmental change, biodiversity at large scales (often termed gamma diversity) is not an additive function of biodiversity at smaller scales (alpha diversity). If global temperature or atmospheric CO 2 concentrations, for example, are increasing at the global scale, the net change over time within local areas must, on average, be positive. However, because local species losses may be accompanied by immigration of species from elsewhere, decreases in biodiversity at the global scale do not necessarily result in any biodiversity change at smaller scales (16, 19, Results and Discussion We conducted a systematic global meta-analysis of plant species diversity change over time in >16,000 plots (median plot area = 44 m 2 ) from all major vegetation types ECOLOGY temporal changes in plant species richness was centered on zero ( We used the interpretations of the authors of the original papers to classify papers according to possible drivers of vegetation change. Recognizing the considerable uncertainty in such interpretations using observational data, we use these categories to explore the possibility of explaining some of the variation among studies, rather than to conduct strong tests of particular hypotheses. Consistent with intuition, marked increases in species richness over time were found in studies in which authors attributed vegetation change to succession following major disturbances such as fire, severe storms, or logging (Postfire and Postdisturbance in Temporal change in species richness was also independent of plot area, temporal duration, and the latitude and longitude of a given study It is important to note that our results do not pertain to species losses caused by human activities at the global scale, for which there is broad scientific consensus and which have justifiably prompted conservation actions based on the ethical, cultural, and instrumental values that people place on different species (16)(17)(18) Our species richness database represents >8,500 cumulative years of change (318 data sets × 27.4-y average time span), covering much of the globe and most of the 20th and early 21st centuries, a period both preceded and characterized by intense human impacts on the earth. Nonetheless, we clearly have an overrepresentation of studies in Europe and North America. Interestingly, the studies from outside Europe and North America show, if anything, a slight tendency toward increasing local-scale species richness When sufficiently profound ecosystem transformations occur, such as converting a forest to a suburban garden or replacing a prairie with a cornfield, we assume that any effect of a change in the number of species on ecosystem function will be negligible compared with the effects of other changes: soil perturbation, a wholesale change in the composition of species, the management regime itself, etc. (6). For example, 100-m 2 plots in European forests in our database contain 14-28 plant species (six studies), whereas a typical domestic garden of the same area in the United Kindom contains almost 100 species (29). Likewise, a monoculture of corn contains far fewer plant species than the prairie it replaced. We argue that such increases (forest-to-garden) or decreases (prairie-to-corn) in species richness per se are effectively irrelevant to understanding changes in ecosystem functions, such as productivity or nutrient cycling, brought about by ecosystem transformation. However, species losses or gains from a forest, grassland, or other ecosystem that otherwise remains untransformed may well have an impact on ecosystem function. As such, the approach in many vegetation resurvey studies of not resurveying areas now occupied by human developments (e.g., forests now covered with residential homes and gardens) If plant biodiversity is not generally declining at local spatial scales, what are the real world implications of small-scale biodiversity manipulation experiments? In some settings, such as forest management or grassland restoration, such experiments closely mimic realistic scenarios (4, 6, Finally, although plant species diversity shows no net directional change at the local scale, individual sites show tremendous variation in the direction and magnitude of biodiversity trends Tundra (7) Savanna/Shrubland ECOLOGY Methods We searched the literature for papers reporting temporal change in the species richness or diversity of plant communities using the following search criteria in SCOPUS on 11 July 2012: [TITLE-ABS-KEY("plant community" OR "plant communities" OR vegetation OR forest* OR grassland* OR wetland* OR desert* OR savanna* OR tundra* OR steppe* OR shrubland* OR prairie* OR taiga OR rainforest* OR woodland* OR mangrove*) AND TITLE-ABS-KEY (biodiversity OR diversity OR richness OR evenness OR composition) AND ALL (resurvey* OR resample* OR revisit* OR "temporal change")]. This search returned 5,247 papers, the titles of which were scanned to eliminate obviously irrelevant papers, resulting in a list of 627 candidate papers. Candidate papers were individually examined for data meeting the following criteria: (i) species richness, diversity, or change in richness/diversity, were reported for two or more points in time spanning at least 5 y; (ii) plots were either permanently marked or semipermanent, the latter indicating that resurveyed plots were located in approximately the same places as originally surveyed plots; (iii) plots were ≤5 ha for surveys of trees or ≤1 ha for all other surveys (the vast majority of plots in the analysis were ≤1,000 m 2 ); and (iv) plots were nonexperimental, in that any human influence was not implemented as part of the study itself; for experimental studies (e.g., nutrient addition, burning), data were recorded for control plots only (see further justification in SI Methods). We searched the reference lists of the initial 627 papers for additional papers potentially with appropriate data, resulting in a second list of 380 papers, which were examined in the same way. We carefully searched for redundancy (i.e., multiple papers reporting data for the same plots), and in such cases retained the paper with the largest sample size and/or the longest duration. Data meeting our criteria were found in 148 papers, comprising 168 studies and 346 data sets (see SI Methods for details and SI Text and Dataset S1 for the raw data). For all data sets, we recorded the number of plots, plot area, plot type (permanent or semipermanent), the first and last years of surveys, country, approximate latitude and longitude, habitat type (forest, grassland, shrubland, savanna/shrubland, wetland, desert, tundra, anthropogenic (e.g., urban), primary succession (postvolcano), many habitats), and the life form(s) surveyed (forb, graminoid, bryophyte, tree, shrub, woody, all). The "all" category for life forms (235/346 data sets) indicated that all plants were recorded, although there was often ambiguity about inclusion of, for example, bryophytes, which might be absent entirely, or tree seedlings in forest understory plots. Mean species richness values were summed across different groups of species in the same plots (e.g., forbs and graminoids, natives and exotics) when such data were presented separately in the original papers. In cases for which the authors of a paper identified a primary driver of temporal vegetation change (262/346 data sets), we used the classification shown in Species richness data were available for 155 studies comprising 318 data sets. For each data set, a raw effect size (ES) was calculated as the log ratio of mean species richness in the last (Y2) and first (Y1) years of surveys (most data sets included only two time points). ES quantifies proportional change between two groups (35), which is appropriate for quantification of temporal change using the initial state as a control and the end state as a treatment (36). The raw log ratio was standardized to a common decadal time scale (35), by dividing by the time interval (t, in decades) between Y1 and Y2: ES = t −1 log(SR Y2 /SR Y1 ). The decadal scale effect size was used in all analyses except to test for the relationship between effect size and study duration. Note that the core result in our paper is insensitive to the decadescale standardization. ES's were analyzed in two ways: (i) presented in the main text, a Bayesian analysis of a multilevel model, in which the nonindependence of multiple data sets within papers is considered explicitly, and in which variation in ES can be related to predictor variables (covariates); and (ii) in the SI Methods, a traditional fixed-effect meta-analysis with each study weighted by the square root of sample size. The same analyses were conducted with ES calculated using diversity or evenness indices except for the evaluation of predictor variables, which was omitted due to small sample size. All analyses were conducted in R version 2.15.2 and OpenBUGS via the R2OpenBUGS package. Additional details are provided in SI Methods. ACKNOWLEDGMENTS. We thank J. Chase, D. Sax, and two anonymous reviewers for input on an earlier draft of the paper. M.V.,

    Global meta-analysis reveals no net change in local-scale plant biodiversity over time

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    Global biodiversity is in decline. This is of concern for aesthetic and ethical reasons, but possibly also for practical reasons, as suggested by experimental studies, mostly with plants, showing that biodiversity reductions in small study plots can lead to compromised ecosystem function. However, inferring that ecosystem functions will decline due to biodiversity loss in the real world rests on the untested assumption that such loss is actually occurring at these small scales in nature. Using a global database of 168 published studies and >16,000 nonexperimental, local-scale vegetation plots, we show that mean temporal change in species diversity over periods of 5–261 y is not different from zero, with increases at least as likely as declines over time. Sites influenced primarily by plant species’ invasions showed a tendency for declines in species richness, whereas sites undergoing postdisturbance succession showed increases in richness over time. Other distinctions among studies had little influence on temporal richness trends. Although maximizing diversity is likely important for maintaining ecosystem function in intensely managed systems such as restored grasslands or tree plantations, the clear lack of any general tendency for plant biodiversity to decline at small scales in nature directly contradicts the key assumption linking experimental results to ecosystem function as a motivation for biodiversity conservation in nature. How often real world changes in the diversity and composition of plant communities at the local scale cause ecosystem function to deteriorate, or actually to improve, remains unknown and is in critical need of further study
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