14,097 research outputs found

    Three things that every medical writer should know about statistics

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    Expanding Our Boundaries With Information Literacy

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    Years ago I had a calling to a special ministry, but I didn\u27t think of it that way. At the time it seemed more a desire, whereas callings had to do with going into overseas missionary work or into a full time Christian ministry. My calling came a few years after the birth of my son when I was working with a capital campaign for the United Presbyterian Church. The $50 million dollar campaign was coming to an end, and that meant my job would soon be over. Although I was offered a higher-level position with the Foundation - one I might add, which had only been held by men up until then, I kept thinking back to a black and white photograph and knew I had to become a librarian

    Insights into enzymatic halogenation from computational studies

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    The halogenases are a group of enzymes that have only come to the fore over the last 10 years thanks to the discovery and characterization of several novel representatives. They have revealed the fascinating variety of distinct chemical mechanisms that nature utilizes to activate halogens and introduce them into organic substrates. Computational studies using a range of approaches have already elucidated many details of the mechanisms of these enzymes, often in synergistic combination with experiment. This Review summarizes the main insights gained from these studies. It also seeks to identify open questions that are amenable to computational investigations. The studies discussed herein serve to illustrate some of the limitations of the current computational approaches and the challenges encountered in computational mechanistic enzymology

    You May Believe You Are a Bayesian But You Are Probably Wrong

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    An elementary sketch of some issues in statistical inference and in particular of the central role of likelihood is given. This is followed by brief outlines of what George Barnard considered were the four great systems of statistical inferences. These can be thought of terms of the four combinations of two factors at two levels. The first is fundamental purpose (decision or inference) and the second probability argument (direct or inverse). Of these four systems the 'fully Bayesiani approach of decision- making using inverse probability particularly associated with the Ramsay, De Finetti, Savage and Lindley has some claims to be the most impressive. It is claimed, however, and illustrated by example, that this approach seems to be impossible to follow. It is speculated that there may be some advantage to the practising statistician to follow George Barnardis advice of being familiar with all four systems.philosophy of statistics, decision theory, likelihood, subjective probability, Bayesianism, Bayes theorem, Fisher, Neyman and Pearson, Jeffreys

    Formation and structure of the ferryl [Fe=O] in-termediate in the non-haem iron halogenase SyrB2: classical and QM/MM modelling agree

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    To rationalise mechanistically the intriguing regio- and chemoselectivity patterns for different substrates of the non-haem iron/2-oxoglutarate dependent halogenase SyrB2, it is crucial to elucidate the structure of the pivotal [FeIV[double bond, length as m-dash]O] intermediate. We have approached the problem by a combination of classical and QM/MM modelling. We present complete atomistic models of SyrB2 in complex with its native substrate L-threonine as well as L-α-amino butyric acid and L-norvaline (all conjugated to the pantetheine tether), constructed by molecular docking and extensive MD simulations. We evaluate five isomers of the [Fe[double bond, length as m-dash]O] intermediate in these simulations, with a view to identifying likely structures based on a simple “reaction distance” measure. Starting from models of the resting state, we then use QM/MM calculations to investigate the formation of the [Fe[double bond, length as m-dash]O] species for all three substrates, identifying the intermediates along the O2 activation/decarboxylation pathway on the S = 1, 2, and 3 potential-energy surfaces. We find that, despite differences in the detailed course of the reaction, essentially all pathways produce the same [Fe[double bond, length as m-dash]O] structure, in which the oxido is directed away from the substrate

    Comment

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    A comment on 'Harold Jeffreys's Theory of Probability Revisited' by Christian P. Robert, Nicolas Chopin, and Judith Roussea

    Managing the complexity: decision making process on sustainable mobility

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    Starting from the literature on decision processes in public choices, aim of the paper is to suggest an integrated methodology to get a choice as much as possible shared and participated joining two different approaches. On one hand there is the “classic†or top-down approach based on statistical data analysis and handling, having as target the definition of some synthetic indicators. On the other hand there is a bottom-up approach based on the Strategic Environment Assessment (SEA) logical framework and on citizens participation. Particularly the paper will apply the above mentioned methodology to face the theme of sustainable mobility showing at the end the results obtained in the analysis of the 13th District of the Municipality of Rome. The choice of sustainable mobility as a target of decision process lies on the fact that actually it is included with a high priority in the agenda of European institutions and (local and national) administrative governments. The proposed model does not provide a solution, but rather defines a process that is able to recognize the particularities of different territorial contexts to yield appropriate, case specific solutions.

    Toward a Unified Performance and Power Consumption NAND Flash Memory Model of Embedded and Solid State Secondary Storage Systems

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    This paper presents a set of models dedicated to describe a flash storage subsystem structure, functions, performance and power consumption behaviors. These models cover a large range of today's NAND flash memory applications. They are designed to be implemented in simulation tools allowing to estimate and compare performance and power consumption of I/O requests on flash memory based storage systems. Such tools can also help in designing and validating new flash storage systems and management mechanisms. This work is integrated in a global project aiming to build a framework simulating complex flash storage hierarchies for performance and power consumption analysis. This tool will be highly configurable and modular with various levels of usage complexity according to the required aim: from a software user point of view for simulating storage systems, to a developer point of view for designing, testing and validating new flash storage management systems

    On Benchmarking Embedded Linux Flash File Systems

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    Due to its attractive characteristics in terms of performance, weight and power consumption, NAND flash memory became the main non volatile memory (NVM) in embedded systems. Those NVMs also present some specific characteristics/constraints: good but asymmetric I/O performance, limited lifetime, write/erase granularity asymmetry, etc. Those peculiarities are either managed in hardware for flash disks (SSDs, SD cards, USB sticks, etc.) or in software for raw embedded flash chips. When managed in software, flash algorithms and structures are implemented in a specific flash file system (FFS). In this paper, we present a performance study of the most widely used FFSs in embedded Linux: JFFS2, UBIFS,and YAFFS. We show some very particular behaviors and large performance disparities for tested FFS operations such as mounting, copying, and searching file trees, compression, etc.Comment: Embed With Linux, Lorient : France (2012

    The Witness of the Worshiping Community

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    (Excerpt) Christ is risen! Alleluia! CR: He is risen indeed! Alleluia!) What more does the church have to do than to proclaim this? What else must the church witness to than the resurrection of the crucified One, who is present in its midst through the preaching of the gospel and the administration of the sacraments? Oh, yes, we have to spin out the meaning of the cross and resurrection of Christ; we have to celebrate it worthily and compellingly in our public assemblies; we have to reorder our lives In conformity with its implications, turning away from the way of the world and toward the new life under Christ\u27s reign; we have to invite others to reorder their lives according to this new reality for the world; and we want to invite them to join us in a community of proclamation and celebration
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