1,157 research outputs found

    Nitrification inhibitors as tool for reduction of greenhouse gas emissions

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    Extending Cross-Modal Retrieval with Interactive Learning to Improve Image Retrieval Performance in Forensics

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    Nowadays, one of the critical challenges in forensics is analyzing the enormous amounts of unstructured digital evidence, such as images. Often, unstructured digital evidence contains precious information for forensic investigations. Therefore, a retrieval system that can effectively identify forensically relevant images is paramount. In this work, we explored the effectiveness of interactive learning in improving image retrieval performance in the forensic domain by proposing Excalibur - a zero-shot cross-modal image retrieval system extended with interactive learning. Excalibur was evaluated using both simulations and a user study. The simulations reveal that interactive learning is highly effective in improving retrieval performance in the forensic domain. Furthermore, user study participants could effectively leverage the power of interactive learning. Finally, they considered Excalibur effective and straightforward to use and expressed interest in using it in their daily practice.Comment: Submitted to the AAAI22 conferenc

    Sesquiterpene Cyclases from the Basidiomycete Cerrena unicolor

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    Hundreds of terpenoids have been isolated from Basidiomycota, among them are volatile mono- and sesquiterpenes with amazing sensory qualities, representing a promising alternative to essential oils from endangered plant species. Sesquiterpene synthases (STS) appear to be an abundant class of enzymes in these fungi. The basidiomycete Cerrena unicolor, a known sesquiterpene producer, was in silico screened for sesquiterpene cyclases via homology Basic Local Alignment Search Tool searches. Cyclase genes identified were cloned and heterologously expressed in Escherichia coli Bl21 using pCOLD I as the expression vector. Ten cyclases were successfully produced and purified, and their identity was confirmed using amino acid sequencing of tryptic peptides by nano-liquid chromatography-high resolution-electrospray ionization-tandem mass spectrometry. Gas chromatography/mass spectrometry analysis was applied to characterize these cyclases according to the formation of sesquiterpene hydrocarbons and oxidized terpenoids. Bioinformatic characterization and phylogenetic determination allowed for the classification of these diverse fungal enzymes. A representative single and a multi-product STS, respectively, were further analyzed for their dependency from divalent metal cations as a cofactor for the catalytic activity

    Impact of Agro-Industrial Side-Streams on Sesquiterpene Production by Submerged Cultured Cerrena unicolor

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    The quality and harvest of essential oils depend on a large number of factors, most of which are hard to control in an open-field environment. Therefore, Basidiomycota have gained attention as a source for biotechnologically produced terpenoids. The basidiomycete Cerrena unicolor (Cun) was cultivated in submerged culture, and the production of sesquiterpenoids was analyzed via stir bar sorptive extraction (SBSE), followed by thermo-desorption gas chromatography coupled with mass spectrometry (TDS-GC-MS). Identification of aroma-active sesquiterpenoids was supported by GC, coupled with an olfactory detection port (ODP). Following the ideal of a circular bioeconomy, Cun was submerged (up-scalable) cultivated, and supplemented with a variety of food industrial side-streams. The effects of the different supplementations and of pure fatty acids were evaluated by liquid extraction and analysis of the terpenoids via GC-MS. As sesquiterpenoid production was enhanced by the most by lipid-rich side-streams, a cultivation with 13C-labeled acetate was conducted. Data confirmed that lipid-rich side-streams enhanced the sesquiterpene production through an increased acetyl-CoA pool

    The Membership and Distance of the Open Cluster Collinder 419

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    The young open cluster Collinder 419 surrounds the massive O star, HD 193322, that is itself a remarkable multiple star system containing at least four components. Here we present a discussion of the cluster distance based upon new spectral classifications of the brighter members, UBV photometry, and an analysis of astrometric and photometric data from the UCAC3 and 2MASS catalogs. We determine an average cluster reddening of E(B-V)=0.37 +- 0.05 mag and a cluster distance of 741 +- 36 pc. The cluster probably contains some very young stars that may include a reddened M3 III star, IRAS~20161+4035

    La organización de la información, los lenguajes documentales y la normalización

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    La calidad de la información que se maneja actualmente ha aumentado debido a las nuevas tecnologías. Esta comunicación se plantea la calidad de la información que los bibliotecarios ofrecen a sus usuarios a través de diversas herramientas : control de autoridades, normalización, normas bibliográficas, lenguajes documentales y encabezamientos de materia

    Frontiers in Behavioral Neuroscience / Brain Oscillatory and Hemodynamic Activity in a Bimanual Coordination Task Following Transcranial Alternating Current Stimulation (tACS) : A Combined EEG-fNIRS Study

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    Motor control is associated with synchronized oscillatory activity at alpha (812 Hz) and beta (1230 Hz) frequencies in a cerebello-thalamo-cortical network. Previous studies demonstrated that transcranial alternating current stimulation (tACS) is capable of entraining ongoing oscillatory activity while also modulating motor control. However, the modulatory effects of tACS on both motor control and its underlying electro- and neurophysiological mechanisms remain ambiguous. Thus, the purpose of this study was to contribute to gathering neurophysiological knowledge regarding tACS effects by investigating the after-effects of 10 Hz tACS and 20 Hz tACS at parietal brain areas on bimanual coordination and its concurrent oscillatory and hemodynamic activity. Twenty-four right-handed healthy volunteers (12 females) aged between 18 and 30 (M = 22.35 3.62) participated in the study and performed a coordination task requiring bimanual movements. Concurrent to bimanual motor training, participants received either 10 Hz tACS, 20 Hz tACS or a sham stimulation over the parietal cortex (at P3/P4 electrode positions) for 20 min via small gel electrodes (3,14 cm2 Ag/AgCl, amperage = 1 mA). Before and three time-points after tACS (immediately, 30 min and 1 day), bimanual coordination performance was assessed. Oscillatory activities were measured by electroencephalography (EEG) and hemodynamic changes were examined using functional near-infrared spectroscopy (fNIRS). Improvements of bimanual coordination performance were not differently between groups, thus, no tACS-specific effect on bimanual coordination performance emerged. However, physiological measures during the task revealed significant increases in parietal alpha activity immediately following 10 Hz tACS and 20 Hz tACS which were accompanied by significant decreases of Hboxy concentration in the right hemispheric motor cortex compared to the sham group. Based on the physiological responses, we conclude that tACS applied at parietal brain areas provoked electrophysiological and hemodynamic changes at brain regions of the motor network which are relevant for bimanual motor behavior. The existence of neurophysiological alterations immediately following tACS, especially in the absence of behavioral effects, are elementary for a profound understanding of the mechanisms underlying tACS. The lack of behavioral modifications strengthens the need for further research on tACS effects on neurophysiology and behavior using combined electrophysiological and neuroimaging methods.(VLID)262473

    Ruling Out Possible Secondary Stars to Exoplanet Host Stars Using the CHARA Array

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    Of the over 450 exoplanets known to date, more than 420 of them have been discovered using radial velocity studies, a method that tells nothing about the inclination of the planet's orbit. Because it is more likely that the companion is a planetary-mass object in a moderate- to high-inclination orbit than a low-mass stellar object in a nearly face-on orbit, the secondary bodies are presumed to be planets. Interferometric observations allow us to inspect the angular diameter fit residuals to calibrated visibilities in order to rule out the possibility of a low-mass stellar companion in a very low-inclination orbit. We used the Center for High Angular Resolution Astronomy (CHARA) Array interferometer to observe 20 exoplanet host stars and considered five potential secondary spectral types: G5 V, K0 V, K5 V, M0 V, and M5 V. If a secondary star is present and is sufficiently bright, the effects of the added light will appear in interferometric observations where the planet will not. All secondary types could be eliminated from consideration for 7 host stars and no secondary stars of any spectral type could be ruled out for 7 more. The remaining 6 host stars showed a range of possible secondary types.Comment: Accepted for publication in the Astronomical Journa

    Detecting and monitoring ice-shelf basal mass balance in Dronning Maud Land, East Antarctica

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    Ice shelves control the dynamic mass loss of ice sheets through buttressing. Their integrity also depends on their total mass balance, with the the spatial variability of their basal mass balance (BMB), i.e. the difference between basal refreezing and melting, being an important component. Here, we present an improved technique – based on satellite observations – to capture the small-scale variability in the BMB of ice shelves. We use mass conservation in a Lagrangian framework based on high-resolution horizontal surface velocities, atmospheric-model surface mass balance and hydrostatic ice-thickness fields (derived from TanDEM-X surface elevation). Spatial derivatives are implemented using the total-variation differentiation, which preserves abrupt changes in flow velocities and their spatial gradients. Such changes may reflect a dynamic response to localized basal melting and should be included in the mass budget. After successfully developing the technique with TanDEM-X elevations from 2013-2014 for the Roi Baudouin Ice Shelf, Dronning Maud Land, East Antarctica (Fig. 1), we upscaled our results spatially to all ice shelves in Dronning Maud Land that are located between Fimbul and Roi Baudouin ice shelves. The BMB field we produce shows a large-scale pattern in close agreement with previous and studies in coarser resolution. However,our results also indicate that we are in addition able to detect small-scale features in the BMB with unprecedented detail (at a gridding of <50 m). Beyond the static field of BMB we also investigate temporal changes in the BMB by combining our BMB basedon TanDEM-X elevations with coarser BMB based on Cryosat-2 data

    The projection factor of delta Cephei A calibration of the Baade-Wesselink method using the CHARA Array

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    6 pages (including an electronic table), accepted for publication in A&A lettersCepheids play a key role in astronomy as standard candles for measuring intergalactic distances. Their distance is usually inferred from the Period-Luminosity relationship, calibrated using the semi-empirical Baade-Wesselink method. Using this method, the distance is known to a multiplicative factor, called the projection factor. Presently, this factor is computed using numerical models - it has hitherto never been measured directly. Based on our new interferometric measurements obtained with the CHARA Array and the already published parallax, we present a geometrical measurement of the projection factor of a Cepheid, delta Cep. The value we determined, p = 1.27±\pm0.06, confirms the generally adopted value of p = 1.36 within 1.5 sigmas. Our value is in line with recent theoretical predictions of Nardetto et al. (2004)
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