1,047 research outputs found

    BGS Library : a world of information

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    Over the last 175 years the British Geological Survey Library has grown and developed into one of the world's major earth science libraries. We have extensive collections of books, maps, journals and BGS publications. We also hold special collections of British geological photographs and archive material, chiefly the historical archives of the BGS. Published material is acquired by exchange with overseas surveys and institutes as well as by purchase. In the past our collections have been enhanced by the incorporation of other collections such as the extensive holdings of the former Overseas Geological Surveys

    Effects of residue-free bands on soil temperature

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    Information transfer in signaling pathways : a study using coupled simulated and experimental data

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    Background: The topology of signaling cascades has been studied in quite some detail. However, how information is processed exactly is still relatively unknown. Since quite diverse information has to be transported by one and the same signaling cascade (e.g. in case of different agonists), it is clear that the underlying mechanism is more complex than a simple binary switch which relies on the mere presence or absence of a particular species. Therefore, finding means to analyze the information transferred will help in deciphering how information is processed exactly in the cell. Using the information-theoretic measure transfer entropy, we studied the properties of information transfer in an example case, namely calcium signaling under different cellular conditions. Transfer entropy is an asymmetric and dynamic measure of the dependence of two (nonlinear) stochastic processes. We used calcium signaling since it is a well-studied example of complex cellular signaling. It has been suggested that specific information is encoded in the amplitude, frequency and waveform of the oscillatory Ca2+-signal. Results: We set up a computational framework to study information transfer, e.g. for calcium signaling at different levels of activation and different particle numbers in the system. We stochastically coupled simulated and experimentally measured calcium signals to simulated target proteins and used kernel density methods to estimate the transfer entropy from these bivariate time series. We found that, most of the time, the transfer entropy increases with increasing particle numbers. In systems with only few particles, faithful information transfer is hampered by random fluctuations. The transfer entropy also seems to be slightly correlated to the complexity (spiking, bursting or irregular oscillations) of the signal. Finally, we discuss a number of peculiarities of our approach in detail. Conclusion: This study presents the first application of transfer entropy to biochemical signaling pathways. We could quantify the information transferred from simulated/experimentally measured calcium signals to a target enzyme under different cellular conditions. Our approach, comprising stochastic coupling and using the information-theoretic measure transfer entropy, could also be a valuable tool for the analysis of other signaling pathways

    Information transfer in signaling pathways : a study using coupled simulated and experimental data

    Get PDF
    Background: The topology of signaling cascades has been studied in quite some detail. However, how information is processed exactly is still relatively unknown. Since quite diverse information has to be transported by one and the same signaling cascade (e.g. in case of different agonists), it is clear that the underlying mechanism is more complex than a simple binary switch which relies on the mere presence or absence of a particular species. Therefore, finding means to analyze the information transferred will help in deciphering how information is processed exactly in the cell. Using the information-theoretic measure transfer entropy, we studied the properties of information transfer in an example case, namely calcium signaling under different cellular conditions. Transfer entropy is an asymmetric and dynamic measure of the dependence of two (nonlinear) stochastic processes. We used calcium signaling since it is a well-studied example of complex cellular signaling. It has been suggested that specific information is encoded in the amplitude, frequency and waveform of the oscillatory Ca2+-signal. Results: We set up a computational framework to study information transfer, e.g. for calcium signaling at different levels of activation and different particle numbers in the system. We stochastically coupled simulated and experimentally measured calcium signals to simulated target proteins and used kernel density methods to estimate the transfer entropy from these bivariate time series. We found that, most of the time, the transfer entropy increases with increasing particle numbers. In systems with only few particles, faithful information transfer is hampered by random fluctuations. The transfer entropy also seems to be slightly correlated to the complexity (spiking, bursting or irregular oscillations) of the signal. Finally, we discuss a number of peculiarities of our approach in detail. Conclusion: This study presents the first application of transfer entropy to biochemical signaling pathways. We could quantify the information transferred from simulated/experimentally measured calcium signals to a target enzyme under different cellular conditions. Our approach, comprising stochastic coupling and using the information-theoretic measure transfer entropy, could also be a valuable tool for the analysis of other signaling pathways

    From blues to rainbows: the mental health and well-being of gender diverse and transgender young people in Australia

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    This study of gender diverse and transgender young people reveals high rates of depression, suicidal thoughts and anxiety. Introduction This report is the culmination of many months of engagement across Australia with young people aged between 14 and 25 who have shared their thoughts, understandings, experiences, hopes and dreams with us through an online survey and online interviews. Their narratives are insightful, touching, and hopeful. Young voices have told us how they care for themselves as well as shining a light on how health services, schools, government and policy makers can better serve their needs. This research was designed to expand on findings from previous Australian research with young people that found that gender-questioning and transgender young people not only experienced higher rates of self-harm and suicidal thoughts, but were also more likely to be involved in activism than their cisgender and same-sex attracted peers. This later finding is a potentially positive one and points to the need for research to not only explore the mental health needs of these young people but also the ways in which they advocate and care for themselves in the face of discrimination and abuse

    The Good, Bad & Ugly of Accessibility in Higher Education Facilities

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    Not every solution for addressing physical access on a campus is a success. Some are outstanding, and some
 not so good. We need to be honest in our evaluation of existing, new, and renovated building on our campuses. This session will examine examples of physical accessibility at the Iowa and Iowa State campus. Participants will gain understanding of the underlying problems and potential solutions for change through best practice discussion and highlighting differing inclusive design strategies used by the two institutions

    Transition from stochastic to deterministic behavior in calcium oscillations

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    Simulation and modeling is becoming more and more important when studying complex biochemical systems. Most often, ordinary differential equations are employed for this purpose. However, these are only applicable when the numbers of participating molecules in the biochemical systems are large enough to be treated as concentrations. For smaller systems, stochastic simulations on discrete particle basis are more accurate. Unfortunately, there are no general rules for determining which method should be employed for exactly which problem to get the most realistic result. Therefore, we study the transition from stochastic to deterministic behavior in a widely studied system, namely the signal transduction via calcium, especially calcium oscillations. We observe that the transition occurs within a range of particle numbers, which roughly corresponds to the number of receptors and channels in the cell, and depends heavily on the attractive properties of the phase space of the respective systems dynamics. We conclude that the attractive properties of a system, expressed, e.g., by the divergence of the system, are a good measure for determining which simulation algorithm is appropriate in terms of speed and realism
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