5,441 research outputs found

    Micrometeoroid velocity-and-trajectory analyzer

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    By adding potential energy of charged capacitor to kinetic energy of impacting particle, new technique causes major fraction of atoms in microscopic particle impacting on particle-receiving surface to be ionized. Chemical constituents of impacting particle are represented by generated ion mass spectrum in approximately correct proportions

    Particle impact location detector

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    Detector includes delay lines connected to each detector surface strip. When several particles strike different strips simultaneously, pulses generated by each strip are time delayed by certain intervals. Delay time for each strip is known. By observing time delay in pulse, it is possible to locate strip that is struck by particle

    A cosmic dust composition analyzed with a spark ion source

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    Simulated iron micrometeoroids were fired unto a capacitor-type micrometeoroid detector which responded to an impact with a spark. Large ion currents were extracted from the spark and analyzed in a crude ion time-of-flight mass spectrometer. The mass spectra show the elements of both detector and particle materials

    AFES Miscellaneous Publication 2008-03

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    Revisiting Visual Question Answering Baselines

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    Visual question answering (VQA) is an interesting learning setting for evaluating the abilities and shortcomings of current systems for image understanding. Many of the recently proposed VQA systems include attention or memory mechanisms designed to support "reasoning". For multiple-choice VQA, nearly all of these systems train a multi-class classifier on image and question features to predict an answer. This paper questions the value of these common practices and develops a simple alternative model based on binary classification. Instead of treating answers as competing choices, our model receives the answer as input and predicts whether or not an image-question-answer triplet is correct. We evaluate our model on the Visual7W Telling and the VQA Real Multiple Choice tasks, and find that even simple versions of our model perform competitively. Our best model achieves state-of-the-art performance on the Visual7W Telling task and compares surprisingly well with the most complex systems proposed for the VQA Real Multiple Choice task. We explore variants of the model and study its transferability between both datasets. We also present an error analysis of our model that suggests a key problem of current VQA systems lies in the lack of visual grounding of concepts that occur in the questions and answers. Overall, our results suggest that the performance of current VQA systems is not significantly better than that of systems designed to exploit dataset biases.Comment: European Conference on Computer Visio

    A composition analyzer for microparticles using a spark ion source

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    Iron microparticles were fired onto a capacitor-type microparticle detector which responded to an impact with a spark discharge. Ion currents were extracted from the spark and analyzed in a time-of-flight mass spectrometer. The mass spectra showed the element of both detector and particle materials. The total extracted ion currents was typically 10A within a period of 100ns, indicating very efficient vaporization of the particle and ionization of the vapor. Potential applications include research on cosmic dust, atmospheric aerosols and cloud droplets, particles ejected by rocket or jet engines, by machining processes, or by nuclear bomb explosions

    Amyloid fibril nucleation: effect of amino acid hydrophobicity

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    We consider the nucleation of amyloid fibrils when the process occurs by direct polymerization of fully extended peptides (i.e., β-strands) into fibrils composed of successively layered β-sheets with alternating weak and strong hydrophobic surfaces. We extend our recently developed nucleation model (Kashchiev, D.; Cabriolu, R.; Auer, S. J. Am. Chem. Soc. 2013, 135, 1531-1539) to derive general expressions for the work to form such fibrils, the fibril solubility, the nucleation work, the equilibrium concentration of nuclei, and the fibril nucleation rate as explicit functions of the supersaturation of the protein solution. Analysis of these expressions illustrates the effect of increased asymmetry between the weak and strong hydrophobic β-sheet surfaces on the thermodynamics and kinetics of the polymerization process. In particular, the application of our theoretical framework to a simple model peptide system shows that lowering the hydrophobicity of one β-sheet surface can hamper protein fibrillation because the threshold concentration below which the fibril nucleation is practically arrested, and above which the process occurs vigorously--because then each monomer in the solution acts as a fibril nucleus--is shifted to higher concentrations. This effect is entirely due to the effect of asymmetry of the two hydrophobic β-sheet surfaces on the fibril solubility. In addition, with increasing asymmetry, the nucleation rate of one fibril polymorph becomes increasingly dominant, illustrating that there is a morphological selection between the two possible polymorphs

    Richard Sulík: A provincial or a European Slovak politician?

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    Europe between reckless optimism and reckless despair

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    The article offers thoughts on the status of politics in Europe. According to the author, the call of the European Union's (EU) elite on the creation of 'more Europe' destroys the societies more politically. Revolutions that influence the future of Europe are being discussed. Additionally, the author argues that the protracted crisis of European integration has caused the deteriorating economic and political condition to European nations.published_or_final_versio

    Power, Weakness and Violence: Revolutions in the twenty-first century

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