992 research outputs found

    An integrated approach to restoring grassland function to working landscapes

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    Nearly all of what was historically tallgrass prairie has been lost due to conversion to agriculture and increasing urbanization. This thesis focuses on strategies to restore native species diversity to working (i.e., agricultural) landscapes in the American Midwest. The practicality and efficacy of restoration of prairie function to working lands has been demonstrated for some taxa in the short-term (i.e., years 1-5), but the effects of continuing consistent management in the medium- and long-term are less studied. I focus here on butterflies and floral resources due to (1) the well-known sensitivity of butterflies to habitat changes (2) the likely concordant response between insect pollinators and floral resources due to their tight ecological relationship and (3) the ecosystem services provided by pollinators and the need to manage lands for such a service. Taken together, this body of work seeks to integrate empirical and modeling approaches to create a more holistic understanding of how grassland restoration strategies affect insect pollinators. Management strategies are frequently recommended on the basis of only a few years of field sampling, after which, research often ceases and is replaced by opportunistic sampling by managers without a formal experimental framework. The first chapter of this thesis examines the effect of a continuous decade of consistent management with pyric-herbivory (i.e., various combinations of fire and grazing) on butterfly and floral resource plant communities. The management methods being considered here are burn-only (i.e., no grazing with the whole site burned once every three years) graze and burn (i.e., cattle grazing the entire site with a full-site burn once every three years), and patch-burn grazing (i.e., cattle grazing the entire site with a burn on one third of the site every year). We find that not only do butterfly and floral resource communities vary in terms of abundance, species richness, and diversity among management strategies; they do so in a way that is not consistent with what is typically observed in studies conducted over a shorter time period (as will be more fully discussed in that chapter). Additionally, while the community composition of butterflies varies significantly among management types in three of the five study years, floral resource community composition does not vary significantly in any study year. This may be indicative of an effect of management on larval (i.e., caterpillar) resources that is not as impactful on the nectar resources upon which adult butterflies depend. The community composition variation in butterflies appears to be primarily driven by the hyper-abundance of particular families of butterflies in each of the three management types. These results demonstrate that short-term responses may not match long-term responses and thus indicate that field studies should take placeā€“where feasibleā€“over more sampling seasons such that management recommendations are more fully informed. When restoring prairie function to working landscapes, one must plan for the effects of anthropogenic climate change. In the second chapter of this thesis, I focus on the potential changes in bioclimatic suitability to plant species included in a restoration seed-mix used to jump-start the reintroduction of a particular community of native plants. Using Species Distribution Modeling (SDM), I correlate occurrence records of a particular species with a suite of climatic variables to predict where suitable bioclimatic conditions might be in the future. Given that SDMs can function well on publicly available data and are relatively intuitive in terms of how they infer changes to predicted distribution, they can be a powerful tool. However, the sheer number of distribution maps generated (one per species per climatic scenario) can be unwieldy in the context of restoration of entire plant communities. We sought therefore to assess whether modeled species exhibited conserved responses to climate change within functional groups. Our results indicate that for forbs, warm-season grasses, and legumes, species within a functional group tend to respond similarly to one another. Cool-season grasses, on the other hand, did not vary in a synchronous fashion, which may be indicative of more variable suitable conditions among species within this group. In addition, some functional groups tended to be much more sensitive (i.e., they demonstrated substantial changes between currently suitable areas and those predicted to be suitable in the future) to climate change conditions than others. Given that forbs tended to exhibit the most dramatic response to climate change, and other groups tended to exhibit more similar current and future distributions, managers interested in restoring flowering plant communities should consider either more southerly ecotypes or congeners to species of interest that are more tolerant of warmer and relatively drier conditions. One important caveat to the use of SDMs in restoration, however, is that such models are best applied at the continental scale (due to problematic assumptions of the role of microhabitat at small spatial scales), whereas land managers are likely interested in the regional or local spatial scale. More spatially precise estimates of the impact of climate change should consider microhabitat, with the SDM outputs presented here and elsewhere informing the areas of interest. Restoration of grassland function must occur in the immediate future if threatened prairie taxa are to be conserved. Such conservation may most profitably focus on increasing the ecological value of agricultural land because such lands occupy a majority of much of the American Midwest. The first chapter of this thesis indicates that the traditional length of field studies may be insufficient in capturing the full consequences of management for butterflies and floral resource. Additionally, single metrics for community response, though informative, are unlikely to be enough in quantifying the full scope of ecologically-meaningful community response and multivariate community composition methods must be included. The second chapter of this thesis suggests that plant species within a functional group generally demonstrate conserved responses to climate change and that functional groups respond differently to potential future conditions. This also serves as evidence that modeling approaches are a useful complement to field methods and can provide an added dimension in creating restoration plans effective in the short-and long-terms. Collectively, the insights presented in this work demonstrate the need for restoration strategy to include many different approaches and emphasize ways in which management can be more likely to be successful in the long term

    Evaluating the Utility of Species Distribution Models in Informing Climate Change-Resilient Grassland Restoration Strategy

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    Tallgrass prairie ecosystems in North America are heavily degraded and require effective restoration strategies if prairie specialist taxa are to be preserved. One common management tool used to restore grassland is the application of a seed-mix of native prairie plant species. While this technique is effective in the short-term, it is critical that species\u27 resilience to changing climate be evaluated when designing these mixes. By utilizing species distribution models (SDMs), species\u27 bioclimatic envelopesā€“and thus the geographic area suitable for themā€“can be quantified and predicted under various future climate regimes, and current seed-mixes may be modified to include more climate resilient species or exclude more affected species. We evaluated climate response on plant functional groups to examine the generalizability of climate response among species of particular functional groups. We selected 14 prairie species representing the functional groups of cool-season and warm-season grasses, forbs, and legumes and we modeled their responses under both a moderate and more extreme predicted future. Our functional group ā€œcomposite mapsā€ show that warm-season grasses, forbs, and legumes responded similarly to other species within their functional group, while cool-season grasses showed less inter-species concordance. The value of functional group as a rough method for evaluating climate-resilience is therefore supported, but candidate cool-season grass species will require more individualized attention. This result suggests that seed-mix designers may be able to use species with more occurrence records to generate functional group-level predictions to assess the climate response of species for which there are prohibitively few occurrence records for modeling

    Evaluating the Utility of Species Distribution Models in Informing Climate Change-Resilient Grassland Restoration Strategy

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    Tallgrass prairie ecosystems in North America are heavily degraded and require effective restoration strategies if prairie specialist taxa are to be preserved. One common management tool used to restore grassland is the application of a seed-mix of native prairie plant species. While this technique is effective in the short-term, it is critical that species' resilience to changing climate be evaluated when designing these mixes. By utilizing species distribution models (SDMs), species' bioclimatic envelopesā€“and thus the geographic area suitable for themā€“can be quantified and predicted under various future climate regimes, and current seed-mixes may be modified to include more climate resilient species or exclude more affected species. We evaluated climate response on plant functional groups to examine the generalizability of climate response among species of particular functional groups. We selected 14 prairie species representing the functional groups of cool-season and warm-season grasses, forbs, and legumes and we modeled their responses under both a moderate and more extreme predicted future. Our functional group ā€œcomposite mapsā€ show that warm-season grasses, forbs, and legumes responded similarly to other species within their functional group, while cool-season grasses showed less inter-species concordance. The value of functional group as a rough method for evaluating climate-resilience is therefore supported, but candidate cool-season grass species will require more individualized attention. This result suggests that seed-mix designers may be able to use species with more occurrence records to generate functional group-level predictions to assess the climate response of species for which there are prohibitively few occurrence records for modeling

    A translational framework for public health research

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    <p><b>Background</b></p> <p>The paradigm of translational medicine that underpins frameworks such as the Cooksey report on the funding of health research does not adequately reflect the complex reality of the public health environment. We therefore outline a translational framework for public health research.</p> <p><b>Discussion</b></p> <p>Our framework redefines the objective of translation from that of institutionalising effective interventions to that of improving population health by influencing both individual and collective determinants of health. It incorporates epidemiological perspectives with those of the social sciences, recognising that many types of research may contribute to the shaping of policy, practice and future research. It also identifies a pivotal role for evidence synthesis and the importance of non-linear and intersectoral interfaces with the public realm.</p> <p><b>Summary</b></p> <p>We propose a research agenda to advance the field and argue that resources for 'applied' or 'translational' public health research should be deployed across the framework, not reserved for 'dissemination' or 'implementation'.</p&gt

    The X-inactivation trans-activator Rnf12 is negatively regulated by pluripotency factors in embryonic stem cells

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    X-inactivation, the molecular mechanism enabling dosage compensation in mammals, is tightly controlled during mouse early embryogenesis. In the morula, X-inactivation is imprinted with exclusive silencing of the paternally inherited X-chromosome. In contrast, in the post-implantation epiblast, X-inactivation affects randomly either the paternal or the maternal X-chromosome. The transition from imprinted to random X-inactivation takes place in the inner cell mass (ICM) of the blastocyst from which embryonic stem (ES) cells are derived. The trigger of X-inactivation, Xist, is specifically downregulated in the pluripotent cells of the ICM, thereby ensuring the reactivation of the inactive paternal X-chromosome and the transient presence of two active X-chromosomes. Moreover, Tsix, a critical cis-repressor of Xist, is upregulated in the ICM and in ES cells where it imposes a particular chromatin state at the Xist promoter that ensures the establishment of random X-inactivation upon differentiation. Recently, we have shown that key transcription factors supporting pluripotency directly repress Xist and activate Tsix and thus couple Xist/Tsix control to pluripotency. In this manuscript, we report that Rnf12, a third X-linked gene critical for the regulation of X-inactivation, is under the control of Nanog, Oct4 and Sox2, the three factors lying at the heart of the pluripotency network. We conclude that in mouse ES cells the pluripotency-associated machinery exerts an exhaustive control of X-inactivation by taking over the regulation of all three major regulators of X-inactivation: Xist, Tsix, and Rnf12

    "Actual" does not imply "feasible"

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    The familiar complaint that some ambitious proposal is infeasible naturally invites the following response: Once upon a time, the abolition of slavery and the enfranchisement of women seemed infeasible, yet these things were actually achieved. Presumably, then, many of those things that seem infeasible in our own time may well be achieved too and, thus, turn out to have been perfectly feasible after all. The Appeal to History, as we call it, is a bad argument. It is not true that if some desirable state of affairs was actually achieved, then it was feasible that it was achieved. ā€œActualā€ does not imply ā€œfeasible,ā€ as we put it. Here is our objection. ā€œFeasibleā€ implies ā€œnot counterfactually fluky.ā€ But ā€œactualā€ does not imply ā€œnot counterfactually fluky.ā€ So, ā€œactualā€ does not imply ā€œfeasible.ā€ While something like the Flukiness Objection is sometimes hinted at in the context of the related literature on abilities, it has not been developed in any detail, and both premises are inadequately motivated. We offer a novel articulation of the Flukiness Objection that is both more precise and better motivated. Our conclusions have important implications, not only for the admissible use of history in normative argument, but also by potentially circumscribing the normative claims that are applicable to us

    Chronic widespread bodily pain is increased among individuals with history of fracture:findings from UK Biobank

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    Acknowledgments This work was supported by grants from the Medical Research Council, British Heart Foundation, Arthritis Research UK, National Osteoporosis Society, International Osteoporosis Foundation, NIHR Southampton Biomedical Research Centre, University of Southampton and University Hospital Southampton NHS Foundation Trust, and NIHR Musculoskeletal Biomedical Research Unit, University of Oxford. This research has been conducted using the UK Biobank Resource. Compliance with ethical standards.Peer reviewedPublisher PD

    LsrR-Mediated Quorum Sensing Controls Invasiveness of Salmonella typhimurium by Regulating SPI-1 and Flagella Genes

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    Bacterial cell-to-cell communication, termed quorum sensing (QS), controls bacterial behavior by using various signal molecules. Despite the fact that the LuxS/autoinducer-2 (AI-2) QS system is necessary for normal expression of Salmonella pathogenicity island-1 (SPI-1), the mechanism remains unknown. Here, we report that the LsrR protein, a transcriptional regulator known to be involved in LuxS/AI-2-mediated QS, is also associated with the regulation of SPI-1-mediated Salmonella virulence. We determined that LsrR negatively controls SPI-1 and flagella gene expressions. As phosphorylated AI-2 binds to and inactivates LsrR, LsrR remains active and decreases expression of SPI-1 and flagella genes in the luxS mutant. The reduced expression of those genes resulted in impaired invasion of Salmonella into epithelial cells. Expression of SPI-1 and flagella genes was also reduced by overexpression of the LsrR regulator from a plasmid, but was relieved by exogenous AI-2, which binds to and inactivates LsrR. These results imply that LsrR plays an important role in selecting infectious niche of Salmonella in QS dependent mode

    Measuring Anxiety in Youth with Learning Disabilities: Reliability and Validity of the Multidimensional Anxiety Scale for Children (MASC)

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    Youth with learning disabilities (LD) are at an increased risk for anxiety disorders and valid measures of anxiety are necessary for assessing this population. We investigated the psychometric properties of the Multidimensional Anxiety Scale for Children (MASC; March in Multidimensional anxiety scale for children. Multi-Health Systems, North Tonawanda, 1998) in 41 adolescents (ages 11ā€“ 17Ā years) with LD. Youth and parents completed the MASC and were administered the semi-structured Anxiety Disorders Interview Schedule: Child and Parent Versions (ADIS: C/P; Silverman and Albano in The Anxiety Disorders Interview Schedule for DSM-IV-Child and Parent Versions. Psychological Corporation, San Antonio, 1996). Results found that child and parent reports of Social Anxiety on the MASC closely corresponded with ADIS-generated social phobia diagnoses, and parent total scores discriminated well among youth with and without any anxiety disorder. A multi-method multi-trait matrix provided evidence of the construct validity of the MASC total score for both parent and child reports. Our findings provide empirical evidence that parent and child versions of the MASC are useful for assessing anxiety in youth with LD
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