284 research outputs found

    Accurate reassembly of small broken test specimens

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    Collets hold specimen in place while epoxy resin cements the broken ends, thereby eliminating relative rotation of the fracture faces. The cemented fracture can then be sectioned metallographically

    High Resolution Image Reconstruction of Polymer Composite Materials Using Neural Networks

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    A neural network is an artificial intelligence technique inspired by a simplistic model of biological neurons and their connectivity. A neural network has the ability to learn an input-output function without a priori knowledge of the relationship between them. Typically a neural network consists of layers of neurons, whereby each neuron in a given layer is fully connected to neurons in adjacent layers. Figure 1 shows such an arrangement with three layers, called the input, hidden and output layers. The connection strengths between neurons, often referred to as weights, are modified by a training phase. The training phase used here utilizes an error back propagation algorithm [1]. During training the neural network is presented with input which propagates through the network producing a corresponding output. A comparison of the actual output with the desired or target output generates an error which is used to adjust the neural network’s weights according to an error gradient descent technique [2]. This procedure is repeated for many different input and desired output pairs allowing the neural network to learn the input-output function

    Large magnetic anisotropy in Ferrihydrite nanoparticles synthesized from reverse micelles

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    Six-line ferrihydrite(FH) nanoparticles have been synthesized in the core of reverse micelles, used as nanoreactors to obtain average particle sizes ≈\approx 2 to 4 nm. The blocking temperatures TBmT_B^m extracted from magnetization data increased from ≈10\approx 10 to 20 K for increasing particle size. Low-temperature \MOS measurements allowed to observe the onset of differentiated contributions from particle core and surface as the particle size increases. The magnetic properties measured in the liquid state of the original emulsion showed that the \FH phase is not present in the liquid precursor, but precipitates in the micelle cores after the free water is freeze-dried. Systematic susceptibility \chi_{ac}(\emph{f},T) measurements showed the dependence of the effective magnetic anisotropy energies EaE_{a} with particle volume, and yielded an effective anisotropy value of Keff=312±10K_{eff} = 312\pm10 kJ/m3^3.Comment: 8 pages, 10 figures. Nanotechnology, v17 (Nov. 2006) In pres

    2007 Report of the ICES Study Group on Fisheries-Induced Adaptive Change (SGFIAC)

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    There is a growing body of scientific evidence indicating that fisheries can cause evolutionary responses over time periods as short as 1020 years, in particular in traits such as the onset of maturation. As these changes will most likely result in a reduction of the productivity of a fish stock, management objectives and (precautionary) reference points for sustainable exploitation need to be re-defined, and new objectives and reference points for managing fisheries-induced evolution need to be developed. Current knowledge allows for two generalisations. First, reducing harvest rates will almost always slow the rate and extent of fisheries-induced evolution in most life-history traits. Second, raising a stock's minimum size limit for exploitation well above the size range over which maturation occurs will slow down the rate of evolution in its maturation schedule. To go beyond these generic insights, "Evolutionary Impact Assessments" (EvoIAs) are proposed to quantify the effects of management measures, through the evolutionary response of specific stocks, on the utility functions defined by managers. The Study Group on Fisheries Induced Adaptive Change [SGFIAC] proposes to further develop this framework in dialogue with fisheries scientists and managers, with the aim of integrating the effects of fisheries-induced evolution into fisheries management advice. Developing EvoIAs in the context of suitable case studies is considered to be the most efficient way for making progress

    Pharmacological characterisation of MDI-222, a novel AMPA receptor positive allosteric modulator with an improved safety profile

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    There is considerable interest in positive allosteric modulators (PAMs) of the α-amino-3-hydroxyl-5-methyl-4-isoxazole-propionate (AMPA) subtype of ionotropic glutamate receptors as therapeutic agents for a range of cognitive and mood disorders. However, the challenge is to increase AMPA receptor (AMPAR) function sufficient to enhance cognitive function but not to the extent that there are mechanism-related pro-convulsant or convulsant side effects. In this present study, we report the preclinical pharmacology data for MDI-222, an AMPAR PAM which enhances cognition but has a much reduced side-effect (i.e. convulsant) liability relative to other molecules of this mechanism

    Mindcontrol: a web application for brain segmentation quality control

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    Tissue classification plays a crucial role in the investigation of normal neural development, brain-behavior relationships, and the disease mechanisms of many psychiatric and neurological illnesses. Ensuring the accuracy of tissue classification is important for quality research and, in particular, the translation of imaging biomarkers to clinical practice. Assessment with the human eye is vital to correct various errors inherent to all currently available segmentation algorithms. Manual quality assurance becomes methodologically difficult at a large scale - a problem of increasing importance as the number of data sets is on the rise. To make this process more efficient, we have developed Mindcontrol, an open-source web application for the collaborative quality control of neuroimaging processing outputs. The Mindcontrol platform consists of a dashboard to organize data, descriptive visualizations to explore the data, an imaging viewer, and an in-browser annotation and editing toolbox for data curation and quality control. Mindcontrol is flexible and can be configured for the outputs of any software package in any data organization structure. Example configurations for three large, open-source datasets are presented: the 1000 Functional Connectomes Project (FCP), the Consortium for Reliability and Reproducibility (CoRR), and the Autism Brain Imaging Data Exchange (ABIDE) Collection. These demo applications link descriptive quality control metrics, regional brain volumes, and thickness scalars to a 3D imaging viewer and editing module, resulting in an easy-to-implement quality control protocol that can be scaled for any size and complexity of study

    Evolutionary impact assessment: accounting for evolutionary consequences of fishing in an ecosystem approach to fisheries management

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    Managing fisheries resources to maintain healthy ecosystems is one of the main goals of the ecosystem approach to fisheries (EAF). while the number of international treaties call for the implementation of EAF, there are still gaps in the underlying methodology. One aspect that has received substantial scientific attention recently in fisheries-induced evolution (FIE). Increasing evidence indicates that intensive fishing has the potential to exert strong directional selection on life-history traits, behavior, physiology, and morphology of exploited fish. Of particular concern is that reversing evolutionary responses to fishing can be much more difficult than reversing demographic or phenotypically plastic responses. Furthermore, like climate change, multiple agents cause fisheries-induced evolution with effects accumulating over time. Consequently, FIE may alter then utility derived from fish stocks, which in turn can modify the monetary value living aquatic resources provide to society. Quantifying and predicting the evolutionary effects of fishing is therefore important for both ecological and economic reasons, An important reason this is not happening is the lack of an appropriate assessment framework. We therefor describe the evolutionary impact assessment (EvoIA) as a structured approach for assessing the evolutionary outcomes of alternative management options. EvoIA can contribute to the ecosystem approach to fisheries management by clarifying how evolution may alter stock properties and ecological relations, support the precautionary approach to fisheries management by addressing a previously overlooked source of uncertainty and risk, and thus contribute to sustainable fisheries
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