313 research outputs found

    The World is Facing a Global Sand Crisis

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    When people picture sand spread across idyllic beaches and endless deserts, they understandably think of it as an infinite resource. But as we discuss in a just-published perspective in the journal Science, over-exploitation of global supplies of sand is damaging the environment, endangering communities, causing shortages and promoting violent conflict

    Scalar Implicature in Chitonga-Speaking Children

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    Research on the acquisition of scalar implicature (SI) has provided evidence that young children interpret SI differently from adults. However, results have varied, and there is now mounting evidence that around six years of age, children are able to derive the pragmatic inferences associated with SI (Foppolo, Guasti, and Chierchia, 2012). Variability in results across studies could be due to factors such as data collection methods and language-specific differences. In order to add to the growing body of literature in a meaningful way, this research investigated the interpretation of sentences that include SI by Chitonga-speaking children (7-15 years old) in rural Southern Province, Zambia, who were notably beyond the key age of six. The results of this study provide valuable insight into the interpretation of SI in a Bantu language and suggest that the acquisition of pragmatic felicity with words on a scale follows the order of acquisition identified in previous research, but may emerge at a later age in this linguistic context

    A database and tool, IM Browser, for exploring and integrating emerging gene and protein interaction data for Drosophila

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    BACKGROUND: Biological processes are mediated by networks of interacting genes and proteins. Efforts to map and understand these networks are resulting in the proliferation of interaction data derived from both experimental and computational techniques for a number of organisms. The volume of this data combined with the variety of specific forms it can take has created a need for comprehensive databases that include all of the available data sets, and for exploration tools to facilitate data integration and analysis. One powerful paradigm for the navigation and analysis of interaction data is an interaction graph or map that represents proteins or genes as nodes linked by interactions. Several programs have been developed for graphical representation and analysis of interaction data, yet there remains a need for alternative programs that can provide casual users with rapid easy access to many existing and emerging data sets. DESCRIPTION: Here we describe a comprehensive database of Drosophila gene and protein interactions collected from a variety of sources, including low and high throughput screens, genetic interactions, and computational predictions. We also present a program for exploring multiple interaction data sets and for combining data from different sources. The program, referred to as the Interaction Map (IM) Browser, is a web-based application for searching and visualizing interaction data stored in a relational database system. Use of the application requires no downloads and minimal user configuration or training, thereby enabling rapid initial access to interaction data. IM Browser was designed to readily accommodate and integrate new types of interaction data as it becomes available. Moreover, all information associated with interaction measurements or predictions and the genes or proteins involved are accessible to the user. This allows combined searches and analyses based on either common or technique-specific attributes. The data can be visualized as an editable graph and all or part of the data can be downloaded for further analysis with other tools for specific applications. The database is available at CONCLUSION: The Drosophila Interactions Database described here places a variety of disparate data into one easily accessible location. The database has a simple structure that maintains all relevant information about how each interaction was determined. The IM Browser provides easy, complete access to this database and could readily be used to publish other sets of interaction data. By providing access to all of the available information from a variety of data types, the program will also facilitate advanced computational analyses

    Testing a Citation and Text-Based Framework for Retrieving Publications for Literature Reviews

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    We propose a citation- and text-based framework to conduct literature review searches. Given a small set of articles included in a literature review (i.e. seed articles), the first step of the framework retrieves articles that are connected to the seed articles in the citation network. The next step filters these retrieved articles using a hybrid citation and text-based criteria. In this paper, we evaluate a first implementation of this framework (code available at https://github.com/janinaj/lit-review-search) by comparing it to the conventional search methods for retrieving the included studies of 6 published systematic reviews. Using different combinations of 3 seed articles, on average we retrieved 71.2% of the total included studies in the published reviews and 82.33% of the studies available in the search database (Scopus). Our best combinations retrieved 87% of the total included studies, which comprised 100% of the studies available in Scopus. In 5 of the 6 reviews, we reduced the number of results by 34–88%, which in practice would save reviewers significant time, since the overall number of search results that need to be manually screened is substantially reduced. These results suggest that our framework is a promising approach to improving the literature review search process.Ope

    Does comorbidity increase the risk of mortality among children under 3 years of age?

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    Objectives Diarrhoea and pneumonia remain leading causes of morbidity and mortality in children under 5 years of age. Little data is available to quantify the burden of comorbidity and the relationship between comorbid diarrhoea and pneumonia infections and mortality. We sought to quantify the relationship between comorbidity and risk of mortality among young children in two community-based studies conducted among South Asian children. Design Secondary data analysis of two cohort studies. Participants We identified two cohort studies of children under 3 years of age with prospective morbidity at least once every 2 weeks and ongoing mortality surveillance. Outcome measures We calculated the mortality risk for diarrhoea and acute lower respiratory infection (ALRI) episodes and further quantified the risk of mortality when both diseases occur at the same time using a semiparametric additive model. Results Among Nepali children, the estimated additional risk of mortality for comorbid diarrhoea and ALRI was 0.0014 (−0.0033, 0.0060). Among South Indian children, the estimated additional risk of mortality for comorbid diarrhoea and ALRI was 0.0032 (−0.0098, 0.0162). This risk is in addition to the single infection risk of mortality observed among these children. Conclusions We observed an additional risk of mortality in children who experienced simultaneous diarrhoea and ALRI episodes though the CI was wide indicating low statistical support. Additional studies with adequate power to detect the increased risk of comorbidity on mortality are needed to improve confidence around the effect size estimate

    Vibratory behaviour of glass fibre reinforced polymer (GFRP) interleaved with nylon nanofibers

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    The main purpose of this study is to investigate the influence of the inclusion of nylon nanofibers on the global dynamic behaviour of GFRP composite laminates. The vibration behaviour of GFRP composites reinforced with nylon nano-fibres is considered experimentally and numerically using a finite element model. The present analysis of clamped-clamped beams investigates the natural frequencies, the damping and the stiffness of virgin and nano-interleaved composite laminates. The numerical modelling uses ANSYS Workbench 16.2. Experimental and numerical results showed a significant effect of the nylon nanofibers on the dynamic behaviour of the composites. Nano-modified composites demonstrated a consistent increase in the damping ratio and inter-laminar strength. However, the variation in natural frequencies and stiffness due to the nanofibers was very small. This study contributes to the knowledge about the macro dynamic properties of nylon interleaved GFRP composites. It demonstrates that a simple FE model can be used to accurately predict the dynamic behaviour of such nano-composites

    Envelope determinants of equine lentiviral vaccine protection

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    Lentiviral envelope (Env) antigenic variation and associated immune evasion present major obstacles to vaccine development. The concept that Env is a critical determinant for vaccine efficacy is well accepted, however defined correlates of protection associated with Env variation have yet to be determined. We reported an attenuated equine infectious anemia virus (EIAV) vaccine study that directly examined the effect of lentiviral Env sequence variation on vaccine efficacy. The study identified a significant, inverse, linear correlation between vaccine efficacy and increasing divergence of the challenge virus Env gp90 protein compared to the vaccine virus gp90. The report demonstrated approximately 100% protection of immunized ponies from disease after challenge by virus with a homologous gp90 (EV0), and roughly 40% protection against challenge by virus (EV13) with a gp90 13% divergent from the vaccine strain. In the current study we examine whether the protection observed when challenging with the EV0 strain could be conferred to animals via chimeric challenge viruses between the EV0 and EV13 strains, allowing for mapping of protection to specific Env sequences. Viruses containing the EV13 proviral backbone and selected domains of the EV0 gp90 were constructed and in vitro and in vivo infectivity examined. Vaccine efficacy studies indicated that homology between the vaccine strain gp90 and the N-terminus of the challenge strain gp90 was capable of inducing immunity that resulted in significantly lower levels of post-challenge virus and significantly delayed the onset of disease. However, a homologous N-terminal region alone inserted in the EV13 backbone could not impart the 100% protection observed with the EV0 strain. Data presented here denote the complicated and potentially contradictory relationship between in vitro virulence and in vivo pathogenicity. The study highlights the importance of structural conformation for immunogens and emphasizes the need for antibody binding, not neutralizing, assays that correlate with vaccine protection

    MtLAX2, a functional homologue of the Arabidopsis auxin influx transporter AUX1, is required for nodule organogenesis

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    Most legume plants can form nodules, specialized lateral organs that form on roots, and house nitrogen-fixing bacteria collectively called rhizobia. The uptake of the phytohormone auxin into cells is known to be crucial for development of lateral roots. To test the role of auxin influx in nodulation we used the auxin influx inhibitors 1-naphthoxyacetic acid (1-NOA) and 2-NOA, which we found reduced nodulation of Medicago truncatula. This suggested the possible involvement of the AUX/LAX family of auxin influx transporters in nodulation. Gene expression studies identified MtLAX2, a paralogue of Arabidopsis (Arabidopsis thaliana) AUX1, as being induced at early stages of nodule development. MtLAX2 is expressed in nodule primordia, the vasculature of developing nodules, and at the apex of mature nodules. The MtLAX2 promoter contains several auxin response elements, and treatment with indole-acetic acid strongly induces MtLAX2 expression in roots. mtlax2 mutants displayed root phenotypes similar to Arabidopsis aux1 mutants, including altered root gravitropism, fewer lateral roots, shorter root hairs, and auxin resistance. In addition, the activity of the synthetic DR5-GUS auxin reporter was strongly reduced in mtlax2 roots. Following inoculation with rhizobia, mtlax2 roots developed fewer nodules, had decreased DR5-GUS activity associated with infection sites, and had decreased expression of the early auxin responsive gene ARF16a. Our data indicate that MtLAX2 is a functional analog of Arabidopsis AUX1 and is required for the accumulation of auxin during nodule formation in tissues underlying sites of rhizobial infection
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