378 research outputs found

    Grazing resistance allows bloom formation and may explain invasion success of Gonyostomum semen

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    The nuisance alga Gonyostomum semen (Raphidophyceae) has expanded in the Nordic countries during the last decades and can dominate lake phytoplankton communities almost completely. A possible explanation to its dominance could be limited grazing by zooplankton. We investigated the potential grazing pressure on G. semen using an experimental approach supported by field data. We determined the grazing rate by cladocerans, calanoid copepods, and Chaoborus larvae to determine which were able to feed on G. semen. Only the large cladoceran Daphnia magna was able to feed successfully on G. semen. The large cell size of G. semen was likely a limiting factor for the filtering apparatus of smaller cladocerans. The copepod Eudiaptomus gracilis did not graze on G. semen, although the mechanism behind this selective feeding is still unknown. In addition to the experimental study, we quantified the zooplankton and phytoplankton communities in 40 lakes to determine the composition and abundance of the zooplankton communities co-occurring with G. semen, suggesting that large cladoceran species were not present in lakes where G. semen occurred. Hence, the growth of G. semen is not significantly controlled by grazing in natural systems, which likely facilitates bloom formation and invasion success of G. semen

    Neurobehavioral effects of transportation noise in primary schoolchildren: a cross-sectional study.

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    This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.BACKGROUND: Due to shortcomings in the design, no source-specific exposure-effect relations are as yet available describing the effects of noise on children's cognitive performance. This paper reports on a study investigating the effects of aircraft and road traffic noise exposure on the cognitive performance of primary schoolchildren in both the home and the school setting. METHODS: Participants were 553 children (age 9-11 years) attending 24 primary schools around Schiphol Amsterdam Airport. Cognitive performance was measured by the Neurobehavioral Evaluation System (NES), and a set of paper-and-pencil tests. Multilevel regression analyses were applied to estimate the association between noise exposure and cognitive performance, accounting for demographic and school related confounders. RESULTS: Effects of school noise exposure were observed in the more difficult parts of the Switching Attention Test (SAT): children attending schools with higher road or aircraft noise levels made significantly more errors. The correlational pattern and factor structure of the data indicate that the coherence between the neurobehavioral tests and paper-and-pencil tests is high. CONCLUSIONS: Based on this study and previous scientific literature it can be concluded that performance on simple tasks is less susceptible to the effects of noise than performance on more complex tasks.Funding was provided by the European Community (QLRT-2000-00197), the Department of Environment, Food and Rural Affairs in the UK, the Dutch Ministry of Spatial Planning, Housing and the Environment, the Dutch Ministry of Public Health, Welfare and Sports, and the Dutch Ministry of Transport, Public Works and Water Management

    Simple Image Description Generator via a Linear Phrase-based Model

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    Generating a novel textual description of an image is an interesting problem that connects computer vision and natural language processing. In this paper, we present a simple model that is able to generate descriptive sentences given a sample image. This model has a strong focus on the syntax of the descriptions. We train a purely bilinear model that learns a metric between an image representation (generated from a previously trained Convolutional Neural Network) and phrases that are used to described them. The system is then able to infer phrases from a given image sample. Based on caption syntax statistics, we propose a simple language model that can produce relevant descriptions for a given test image using the phrases inferred. Our approach, which is considerably simpler than state-of-the- art models, achieves comparable results on the recently release Microsoft COCO dataset

    Twitter Sentiment Analysis (Almost) from Scratch

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    A popular application in Natural Language Processing (NLP) is the Sentiment Analysis (SA), i.e., the task of extracting contextual polarity from a given text. The social network Twitter provides an immense amount of text (called tweets) generated by users with a maximum number of 140 characters. In this project, we plan to learn a tweet representation from publicly provided data from Tweets in order to infer sentiment from them. One challenge on this task is the fact that tweets are generated from very different users, making the data very heterogeneous (different from regular data which is written in proper English). Another challenge is, clearly, the large scale of the problem. We propose a deep learning sentence representation (called tweet representation) from user generated data to infer sentiment from tweets. This representation is learned from scratch (directly from the words in tweet) over a large unlabeled corpus of tweets. We demonstrate that we achieve state-of-the-art results for SA on tweets

    Fast Fourier Optimization: Sparsity Matters

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    Many interesting and fundamentally practical optimization problems, ranging from optics, to signal processing, to radar and acoustics, involve constraints on the Fourier transform of a function. It is well-known that the {\em fast Fourier transform} (fft) is a recursive algorithm that can dramatically improve the efficiency for computing the discrete Fourier transform. However, because it is recursive, it is difficult to embed into a linear optimization problem. In this paper, we explain the main idea behind the fast Fourier transform and show how to adapt it in such a manner as to make it encodable as constraints in an optimization problem. We demonstrate a real-world problem from the field of high-contrast imaging. On this problem, dramatic improvements are translated to an ability to solve problems with a much finer grid of discretized points. As we shall show, in general, the "fast Fourier" version of the optimization constraints produces a larger but sparser constraint matrix and therefore one can think of the fast Fourier transform as a method of sparsifying the constraints in an optimization problem, which is usually a good thing.Comment: 16 pages, 8 figure

    Green Space Visits among Adolescents: Frequency and Predictors in the PIAMA Birth Cohort Study.

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    Green space may influence health through several pathways, for example, increased physical activity, enhanced social cohesion, reduced stress, and improved air quality. For green space to increase physical activity and social cohesion, spending time in green spaces is likely to be important

    Urinary pesticide mixture patterns and exposure determinants in the adult population from the Netherlands and Switzerland : Application of a suspect screening approach

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    INTRODUCTION: Non-occupational sources of pesticide exposure may include domestic pesticide usage, diet, occupational exposure of household members, and agricultural activities in the residential area. We conducted a study with the ambition to characterize pesticide mixture patterns in a sample of the adult population of the Netherlands and Switzerland, using a suspect screening approach and to identify related exposure determinants. METHODS: A total of 105 and 295 adults participated in the Dutch and Swiss studies, respectively. First morning void urine samples were collected and analyzed in the same laboratory. Harmonized questionnaires about personal characteristics, pesticide-related activities, and diet were administered. Detection rates and co-occurrence patterns were calculated to explore internal pesticide exposure patterns. Censored linear and logistic regression models were constructed to investigate the association between exposure and domestic pesticide usage, consumption of homegrown and organic foods, household members' exposure, and distance to agricultural and forest areas. RESULTS: From the 37 detected biomarkers, 3 (acetamiprid (-CH2), chlorpropham (4-HSA), and flonicamid (-C2HN)) were detected in ≥40% of samples. The most frequent combination of biomarkers (acetamiprid-flonicamid) was detected in 22 (5.5%) samples. Regression models revealed an inverse association between high organic vegetable and fruit consumption and exposure to acetamiprid, chlorpropham, propamocarb (+O), and pyrimethanil (+O + SO3). Within-individual correlations in repeated samples (summer/winter) from the Netherlands were low (≤0.3), and no seasonal differences in average exposures were observed in Switzerland. CONCLUSION: High consumption of organic fruit and vegetables was associated with lower pesticide exposure. In the two countries, detection rates and co-occurrence were typically low, and within-person variability was high. Our study results provide an indication for target biomarkers to include in future studies aimed at quantifying urinary exposure levels in European adult populations

    Encuesta de datos demográficos y fenotípicos de razas locales de cerdos del proyecto TREASURE

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    The paper reports the results of a survey on the demographic and phenotypic characterization of 20 European local pig breeds involved in the H2020 TREASURE project including information on: demographic parameters, main morphological features, reproductive information, additional information collected at herd-level (i.e. temperament, holding, mating practices), origins and development of the breeds. Almost all the breeds (18 out of 20) possess a herd book even if the starting year is highly variable (from 1980 to 2006). Number of breeding females ranged from 24 (Moravka) to over 200,000 heads (Ibérico). Male/female ratio varied greatly with the highest values for the Italian breeds probably due to the different policy of animal recording. Almost all the breeds undergo a conservation program whereas really few are interested by other conservation techniques and for less than five breeds data related to effective number and inbreeding coefficient are easily available. Average values for teat number, litter size and weaned piglets are 12, 8 and 6 respectively with a great potential for their improvement. The depicted scenario is highly diversified and the data collected represent the starting point for the achievement of a collective trademark under the umbrella of the TREASURE project
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