231 research outputs found

    Analyzing customer sentiments in microblogs – A topic-model-based approach for Twitter datasets

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    In the Social Commerce customers evolve to an important information source for companies. The customers use communication platforms of the Web 2.0, for example Twitter, in order to express their opinions about products or discuss their experiences with them. These opinions can be very important for the development of products or the product range of a company. Our approach enables a company viewing opinions about its products which are published using the microblogging service Twitter. A first step in our research progress is detecting topics in a specific context. In a further step the entries corresponding to these topics has to be analyzed for opinions. For topic detection we use topic modeling with the Latent Dirichlet Allocation. In our paper we found event-based topics in the context of Sony’s 3D TV sets. In future work we are able to implement Opinion Mining algorithms to determine sentiments in the entries corresponding to the detected topics

    Enhanced carbon overconsumption in response to increasing temperatures during a mesocosm experiment

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    Increasing concentrations of atmospheric carbon dioxide are projected to lead to an increase in sea surface temperatures, potentially impacting marine ecosystems and biogeochemical cycling. Here we conducted an indoor mesocosm experiment with a natural plankton community taken from the Baltic Sea in summer. We induced a plankton bloom via nutrient addition and followed the dynamics of the different carbon and nitrogen pools for a period of one month at temperatures ranging from 9.5 °C to 17.5 °C, representing a range of ± 4 °C relative to ambient temperature. The uptake of dissolved inorganic carbon (DIC) and the net build-up of both particulate (POC) and dissolved organic carbon (DOC) were all enhanced at higher temperatures and almost doubled over a temperature gradient of 8 °C. Furthermore, elemental ratios of carbon and nitrogen (C:N) in both particulate and dissolved organic matter increased in response to higher temperatures, both reaching very high C:N ratios of >30 at +4 °C. Altogether, these observations suggest a pronounced increase in excess carbon fixation in response to elevated temperatures. Most of these findings are contrary to results from similar experiments conducted with plankton populations sampled in spring, revealing large uncertainties in our knowledge of temperature sensitivities of key processes in marine carbon cycling. Since a major difference to previous mesocosm experiments was the dominant phytoplankton species, we hypothesize that species composition might play an important role in the response of biogeochemical cycling to increasing temperatures

    Conformator: A Novel Method for the Generation of Conformer Ensembles

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    Computer-aided drug design methods such as docking, pharmacophore searching, 3D database searching, and the creation of 3D-QSAR models need conformational ensembles to handle the flexibility of small molecules. Here, we present Conformator, an accurate and effective knowledge-based algorithm for generating conformer ensembles. With 99.9% of all test molecules processed, Conformator stands out by its robustness with respect to input formats, molecular geometries, and the handling of macrocycles. With an extended set of rules for sampling torsion angles, a novel algorithm for macrocycle conformer generation, and a new clustering algorithm for the assembly of conformer ensembles, Conformator reaches a median minimum root-mean-square deviation (measured between protein-bound ligand conformations and ensembles of a maximum of 250 conformers) of 0.47 Ã… with no significant difference to the highest-ranked commercial algorithm OMEGA and significantly higher accuracy than seven free algorithms, including the RDKit DG algorithm. Conformator is freely available for noncommercial use and academic research.acceptedVersio

    Stronger Security for Sanitizable Signatures

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    Sanitizable signature schemes (SSS) enable a designated party (called the sanitizer ) to alter admissible blocks of a signed message. This primitive can be used to remove or alter sensitive data from already signed messages without involvement of the original signer. Current state-of-the-art security definitions of SSSs only dene a \weak form of security. Namely, the unforgeability, accountability and transparency definitions are not strong enough to be meaningful in certain use-cases. We identify some of these use-cases, close this gap by introducing stronger definitions, and show how to alter an existing construction to meet our desired security level. Moreover, we clarify a small yet important detail in the state-of-the-art privacy definition. Our work allows to deploy this primitive in more and different scenarios

    Worüber reden die Kunden? – Ein modelbasierter Ansatz für die Analyse von Kundenmeinungen in Microblogs

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    Im Social Commerce entwickeln sich die Kunden zu einer bedeutenden Informationsquelle für Unternehmen. Die Kunden nutzen die Kommunikationsplattformen des Web 2.0 (z.B. Twitter), um ihre Meinungen und Erfahrungen über Produkte zu äußern. Diese Diskussionen können sehr wichtig für die Entwicklung von Produkten eines Unternehmens sein. Ein modellbasierter Ansatz soll es einem Unternehmen ermöglichen, die Meinungen zu seinen Produkten in Microblogs zu betrachten. Der erste Schritt dafür ist die Erkennung von Themen in einem spezifischen Kontext. In einem weiteren Schritt müssen die zu den Themen korrespondierenden Einträge bezüglich der geäußerten Meinungen analysiert werden. Für die Erkennung der Themen kommt ein Verfahren zum Einsatz, das auf der Latent Dirichlet Allocation basiert. Das Verfahren identifizierte eventbasierte Themen im Zusammenhang mit den 3D-TV-Anlagen von Sony

    Greenhouse gas and ammonia emissions from slurry storage: impacts of temperature and potential mitigation through covering (pig slurry) or acidification (cattle slurry)

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    Storage of livestock slurries is a significant source of methane (CH4) and ammonia (NH3) emissions to the atmosphere, for which accurate quantification and potential mitigation methods are required. Methane and NH3 emissions were measured from pilot-scale cattle slurry (CS) and pig slurry (PS) stores under cool, temperate, and warm conditions (approximately 8, 11, and 17°C, respectively) and including two potential mitigation practices: (i) a clay granule floating cover (PS) and (ii) slurry acidification (CS). Cumulative emissions of both gases were influenced by mean temperature over the storage period. Methane emissions from the control treatments over the 2-mo storage periods for the cool, temperate, and warm periods were 0.3, 0.1, and 34.3 g CH4 kg−1 slurry volatile solids for CS and 4.4, 20.1, and 27.7 g CH4 kg−1 slurry volatile solids for PS. Respective NH3 emissions for each period were 4, 7, and 12% of initial slurry N content for CS and 12, 18, and 28% of initial slurry N content for PS. Covering PS with clay granules reduced NH3 emissions by 77% across the three storage periods but had no impact on CH4 emissions. Acidification of CS reduced CH4 and NH3 emissions by 61 and 75%, respectively, across the three storage periods. Nitrous oxide emissions were also monitored but were insignificant. The development of approaches that take into account the influence of storage timing (temperature) and duration on emission estimates for national emission inventory purposes is recommended

    Partial Remodeling after Conservative Treatment of Trampoline Fractures in Children

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    (1) Background: Trampoline fractures (proximal tibia fracture with positive anterior tilt) are increasing. This study represents the first attempt to determine the extent of remodeling in these fractures after conservative treatment (2) Methods: This Swiss prospective multicenter study included children aged 2 to 5 years with a trampoline fracture who were radiologically examined on the day of the accident and after one year. In addition, the anterior tilt angle was compared between the injured and unaffected tibia. Remodeling was defined as complete (final anterior tilt angle ≤ 0°), incomplete (smaller but still >0°), or no remodeling. (3) Results: The mean extent of remodeling was −3.5° (95% CI: −4.29°, −2.66°, p p 1 year after the trauma showed advanced remodeling, suggesting that one year is too short to observe complete remodeling

    Dissemination of antibiotic resistance genes from antibiotic producers to pathogens

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    AbstractIt has been hypothesized that some antibiotic resistance genes (ARGs) found in pathogenic bacteria derive from antibiotic-producing actinobacteria. Here we provide bioinformatic and experimental evidence supporting this hypothesis. We identify genes in proteobacteria, including some pathogens, that appear to be closely related to actinobacterial ARGs known to confer resistance against clinically important antibiotics. Furthermore, we identify two potential examples of recent horizontal transfer of actinobacterial ARGs to proteobacterial pathogens. Based on this bioinformatic evidence, we propose and experimentally test a ‘carry-back’ mechanism for the transfer, involving conjugative transfer of a carrier sequence from proteobacteria to actinobacteria, recombination of the carrier sequence with the actinobacterial ARG, followed by natural transformation of proteobacteria with the carrier-sandwiched ARG. Our results support the existence of ancient and, possibly, recent transfers of ARGs from antibiotic-producing actinobacteria to proteobacteria, and provide evidence for a defined mechanism.</jats:p

    Moment-To-moment affective dynamics in schizophrenia and bipolar disorder

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    Background: Affective disturbances in schizophrenia and bipolar disorder may represent a transdiagnostic etiological process as well as a target of intervention. Hypotheses on similarities and differences in various parameters of affective dynamics (intensity, successive/acute changes, variability, and reactivity to stress) between the two disorders were tested.Methods: Experience sampling method was used to assess dynamics of positive and negative affect, 10 times a day over 6 consecutive days. Patients with schizophrenia (n = 46) and patients with bipolar disorder (n = 46) were compared against age-matched healthy controls (n = 46).Results: Compared to controls, the schizophrenia group had significantly more intense momentary negative affect, a lower likelihood of acute changes in positive affect, and reduced within-person variability of positive affect. The bipolar disorder group was not significantly different from either the schizophrenia group or the healthy control group on any affect indexes. Within the schizophrenia group, level of depression was associated with weaker reactivity to stress for negative affect. Within the bipolar disorder group, level of depression was associated with lower positive affect.Conclusions: Patients with schizophrenia endured a more stable and negative affective state than healthy individuals, and were less likely to be uplifted in response to happenings in daily life. There is little evidence that these affective constructs characterize the psychopathology of bipolar disorder; such investigation may have been limited by the heterogeneity within group. Our findings supported the clinical importance of assessing multiple facets of affective dynamics beyond the mean levels of intensity.</p

    Moment-To-moment affective dynamics in schizophrenia and bipolar disorder

    Get PDF
    Background: Affective disturbances in schizophrenia and bipolar disorder may represent a transdiagnostic etiological process as well as a target of intervention. Hypotheses on similarities and differences in various parameters of affective dynamics (intensity, successive/acute changes, variability, and reactivity to stress) between the two disorders were tested.Methods: Experience sampling method was used to assess dynamics of positive and negative affect, 10 times a day over 6 consecutive days. Patients with schizophrenia (n = 46) and patients with bipolar disorder (n = 46) were compared against age-matched healthy controls (n = 46).Results: Compared to controls, the schizophrenia group had significantly more intense momentary negative affect, a lower likelihood of acute changes in positive affect, and reduced within-person variability of positive affect. The bipolar disorder group was not significantly different from either the schizophrenia group or the healthy control group on any affect indexes. Within the schizophrenia group, level of depression was associated with weaker reactivity to stress for negative affect. Within the bipolar disorder group, level of depression was associated with lower positive affect.Conclusions: Patients with schizophrenia endured a more stable and negative affective state than healthy individuals, and were less likely to be uplifted in response to happenings in daily life. There is little evidence that these affective constructs characterize the psychopathology of bipolar disorder; such investigation may have been limited by the heterogeneity within group. Our findings supported the clinical importance of assessing multiple facets of affective dynamics beyond the mean levels of intensity.</p
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