4,850 research outputs found

    Nonflammable, antistatic, and heat-sealable film

    Get PDF
    Antistatic, heat-sealable, nonflammable films prepared from polyvinylidene fluoride and polyvinylidene chloride resin

    Network Inference via the Time-Varying Graphical Lasso

    Full text link
    Many important problems can be modeled as a system of interconnected entities, where each entity is recording time-dependent observations or measurements. In order to spot trends, detect anomalies, and interpret the temporal dynamics of such data, it is essential to understand the relationships between the different entities and how these relationships evolve over time. In this paper, we introduce the time-varying graphical lasso (TVGL), a method of inferring time-varying networks from raw time series data. We cast the problem in terms of estimating a sparse time-varying inverse covariance matrix, which reveals a dynamic network of interdependencies between the entities. Since dynamic network inference is a computationally expensive task, we derive a scalable message-passing algorithm based on the Alternating Direction Method of Multipliers (ADMM) to solve this problem in an efficient way. We also discuss several extensions, including a streaming algorithm to update the model and incorporate new observations in real time. Finally, we evaluate our TVGL algorithm on both real and synthetic datasets, obtaining interpretable results and outperforming state-of-the-art baselines in terms of both accuracy and scalability

    Several types of types in programming languages

    Get PDF
    Types are an important part of any modern programming language, but we often forget that the concept of type we understand nowadays is not the same it was perceived in the sixties. Moreover, we conflate the concept of "type" in programming languages with the concept of the same name in mathematical logic, an identification that is only the result of the convergence of two different paths, which started apart with different aims. The paper will present several remarks (some historical, some of more conceptual character) on the subject, as a basis for a further investigation. The thesis we will argue is that there are three different characters at play in programming languages, all of them now called types: the technical concept used in language design to guide implementation; the general abstraction mechanism used as a modelling tool; the classifying tool inherited from mathematical logic. We will suggest three possible dates ad quem for their presence in the programming language literature, suggesting that the emergence of the concept of type in computer science is relatively independent from the logical tradition, until the Curry-Howard isomorphism will make an explicit bridge between them.Comment: History and Philosophy of Computing, HAPOC 2015. To appear in LNC

    Lake Erie 1993, Western, West Central and Eastern Basins: Change in Trophic Status, and Assessment of the Abundance, Biomass and Production of the Lower Trophic Levels

    Get PDF
    The western and west central basins were mesotrophic and the eastern basin was oligotrophic, based on many biological and chemical parameters measured in 1993. Gradients were observed for most parameters, with chlorophyll a, nitrogen, phosphorus, silica, and light extinction decreasing from west to east. In the western basin, phytoplankton biomass declined by 51% from 1983-85. Phytoplankton photosynthesis (g C·m-2), predicted from total phosphorus (TP) using a relationship developed in other offshore productivity studies in Lake Ontario, declined by 35% in 1993, without a corresponding decline in phosphorus (P) loading or TP. Diatoms decreased and there was a shift towards smaller phytoplankton species. These changes were attributed to zebra mussel filtration, but were not of sufficient magnitude to reduce zooplankton biomass. In the west central basin, the reductions in phytoplankton biomass were modest. Photosynthesis (g C·m-2) in 1993, was in line with that predicted by TP and the empirical relationship developed in other offshore studies. Limited mussel populations in the west central basin, resulting from low hypolimnetic oxygen concentrations, caused little change in the phytoplankton. There also were no reductions in mean biomass of zooplankton from 1984-87. In the eastern basin, phytoplankton biomass declined by 49% from 1983-85. Photosynthesis (g C·m-2) declined by 50% from the value predicted, from TP and the empirical relationship developed for other studies, for 1983-85, without a decline in P-leading. TP was lower in 1993 and was attributed to filtering by Dreissena and subsequent redirection of pelagic material to the sediments. Phytoplankton species indicative of eutrophy were reduced and there was an overall shift towards smaller species. Zooplankton biomass was also reduced. Mean zooplankton community size and the loss of Daphnia sp. suggest that predation by planktivores as well as a reduced food supply, affected zooplankton biomass in 1993. The Dreissena population also affected the benthic community structure as Diporeia were virtually eliminated from the eastern basin and Gammarus increased in all basins. Benthic biomass was 40% higher on average than in 1979. Dreissena dominated benthic production at all stations except offshore in the west-central basin

    Assessment of Abundance, Biomass and Production of the Lower Trophic Levels in the Eastern Basin of Lake Erie, 1994

    Get PDF
    The Lake Erie Biomonitoring (LEB) program conducted in 1994, focused on the eastern basin of the lake, resampling the same sites as in 1993. Nutrient conditions were similar in the two years. Responses differed between the stratified offshore and unstratified nearshore. At the offshore station, seasonal phytoplankton biomass was 56% higher in 1994 than in 1993 and apparently resulted from a reduction in grazing pressure by Dreissena. Dreissena biomass and their potential clearance rates at the offshore station were much lower in the spring of 1994 than in the spring of 1993 (2.5 vs. 14.9 m3·m·2·d·\u27), respectively. Despite this increase in phytoplankton biomass, chlorophyll (Chi) and phytoplankton photosynthesis (PP) were not significantly higher in 1994. Dinoflagellates, which have lower Chl:C and lower photosynthesis:Chl ratios than other groups of phytoplankton, accounted for much of the increase in biomass. Rotifer biomass decreased by 50% and zooplankton biomass by 40% between the two years. Calanoids were responsible for much of the decrease in zooplankton biomass. Composition also shifted towards larger bodied cladocerans, such as Daphnia and Bythotrephes, and away from Bosmina. This shift coincided with changes in predation pressure. Age-one smelt abundance was extremely high in 1993 and low in 1994, while the reverse was true of the YOY smelt. Age-one smelt consume mainly cladocerans and the YOY, copepods (REF). At the nearshore stations, seasonal PP and Chi were well below that expected given the total phosphorus (TP) concentration, indicating that Dreissena had an important impact on phytoplankton photosynthesis in this region. Low transparency due to suspended sediments also contributed to the low PP at station El. Zooplankton biomass was lower in 1994 than in 1993, and species composition and size shifted. Daphnia increased and calanoids and Bosmina decreased in the nearshore as in the offshore, presumably in response to changes in the smelt population. However, Bythotrephes decreased and rotifer biomass increased unlike in the offshore

    Convolutional LSTM Networks for Subcellular Localization of Proteins

    Get PDF
    Machine learning is widely used to analyze biological sequence data. Non-sequential models such as SVMs or feed-forward neural networks are often used although they have no natural way of handling sequences of varying length. Recurrent neural networks such as the long short term memory (LSTM) model on the other hand are designed to handle sequences. In this study we demonstrate that LSTM networks predict the subcellular location of proteins given only the protein sequence with high accuracy (0.902) outperforming current state of the art algorithms. We further improve the performance by introducing convolutional filters and experiment with an attention mechanism which lets the LSTM focus on specific parts of the protein. Lastly we introduce new visualizations of both the convolutional filters and the attention mechanisms and show how they can be used to extract biological relevant knowledge from the LSTM networks

    HITRAP: A facility at GSI for highly charged ions

    Full text link
    An overview and status report of the new trapping facility for highly charged ions at the Gesellschaft fuer Schwerionenforschung is presented. The construction of this facility started in 2005 and is expected to be completed in 2008. Once operational, highly charged ions will be loaded from the experimental storage ring ESR into the HITRAP facility, where they are decelerated and cooled. The kinetic energy of the initially fast ions is reduced by more than fourteen orders of magnitude and their thermal energy is cooled to cryogenic temperatures. The cold ions are then delivered to a broad range of atomic physics experiments.Comment: 8 pages, 11 figure

    Change of the ice rheology with climatic transitions – implication on ice flow modelling and dating of the EPICA Dome C core

    No full text
    International audienceThe study of the distribution of the crystallographic orientations (the fabric) along ice cores supplies information on the past and current ice flows of ice-sheets. Beside the usually observed formation of a vertical single maximum fabric, the EPICA Dome Concordia ice core (EDC) shows an abrupt and unexpected strenghtening of its fabric during termination II around 1750 m depth. Such strengthenings were already observed for sites located on an ice-sheet. This suggests that horizontal shear could occur along the EDC core. Moreover, the change in the fabric leads to a modification of the viscosity between neighbouring ice layers. Through the use of an anisotropic ice flow model, we quantify the change in viscosity and investigate its implication on ice flow and dating

    Change in ice rheology during climate variations – implications for ice flow modelling and dating of the EPICA Dome C core

    Get PDF
    The study of the distribution of crystallographic orientations (i.e., the fabric) along ice cores provides information on past and current ice flow in ice-sheets. Besides the usually observed formation of a vertical single maximum fabric, the EPICA Dome C ice core (EDC) shows an abrupt and unexpected strengthening of its fabric during termination II around 1750 m depth. Such strengthening has already been observed for sites located on an ice-sheet flank. This suggests that horizontal shear could occur along the EDC core. Moreover, the change in the fabric leads to a modification of the effective viscosity between neighbouring ice layers. Through the use of an anisotropic ice flow model, we quantify the change in effective viscosity and investigate its implication for ice flow and dating
    • …
    corecore