N deposition and elevated CO2 on methane emissions: Differential responses of indirect effects compared to direct effects through litter chemistry feedbacks

Increases in atmospheric CO2 concentration and N deposition are expected to affect methane (CH4) production in soils and emission to the atmosphere, directly through increased plant litter production and indirectly through changes in substrate quality. We examined how CH4 emission responded to changes in litter quality under increased N and CO2, beyond differences in CH4 resulting from changes in litter production. We used senesced leaves from 13C-labeled plants of Molinia caerulea grown at elevated and ambient CO2 and affected by N fertilization to carry out two experiments: a laboratory litter incubation and a pot experiment. N fertilization increased N and decreased C concentrations in litter whereas elevated CO2 decreased litter quality as reflected in litter C and N concentrations and in the composition of lignin and saturated fatty acids within the litter. In contrast to our expectations, CH4 production in the laboratory incubation decreased when using litter from N-fertilized plants as substrate, whereas litter from elevated CO2 had no effect, compared to controls without N and at ambient CO2. Owing to high within-treatment variability in CH4 emissions, none of the treatment effects were reflected in the pot experiment. C mineralization rates were not affected by any of the treatments. The decrease in CH4 emissions due to indirect effects of N availability through litter quality changes (described here for the first time) contrast direct effects of N fertilization on CH4 production. The complex interaction of direct effects with indirect effects of increased N on litter quality may potentially result in a net decrease in CH4 emissions from wetlands in the long term.Fil: Pancotto, Veronica Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Bodegom, P. M. van. University Of Amsterdam; Países BajosFil: Hal, J. van. University Of Amsterdam; Países BajosFil: Logtestijn, R. S. P. van. University Of Amsterdam; Países BajosFil: Blokker, P.. University Of Amsterdam; Países BajosFil: Toet, S.. University Of Amsterdam; Países Bajos. University Of York; Reino UnidoFil: Aerts, R.. University Of Amsterdam; Países Bajo

Efficiency improvement by navigated safety inspection involving visual clutter based on the random search model.

Navigated inspection seeks to improve hazard identification (HI) accuracy. With tight inspection schedule, HI also requires efficiency. However, lacking quantification of HI efficiency, navigated inspection strategies cannot be comprehensively assessed. This work aims to determine inspection efficiency in navigated safety inspection, controlling for the HI accuracy. Based on a cognitive method of the random search model (RSM), an experiment was conducted to observe the HI efficiency in navigation, for a variety of visual clutter (VC) scenarios, while using eye-tracking devices to record the search process and analyze the search performance. The results show that the RSM is an appropriate instrument, and VC serves as a hazard classifier for navigation inspection in improving inspection efficiency. This suggests a new and effective solution for addressing the low accuracy and efficiency of manual inspection through navigated inspection involving VC and the RSM. It also provides insights into the inspectors' safety inspection ability

Effects of Multisensory Context on Tofu and Soy Sauce Evaluation and Consumption

We examined the effects of an informative pitch and multisensory contexts as potential factors influencing individuals’ experience of tofu with soy sauce and the amount consumed outside the lab. Two hundred and sixteen participants watched one of two pitches (promoting either vegetarian diets or exercise) and were guided into one of three multisensory contexts (‘sustainable’, ‘meat’, or ‘neutral’ theme). Participants rated the aroma and appearance of soy sauce and the taste of tofu dipped in it using the intuitive ‘one touch’ EmojiGrid valence and arousal measuring tool. Our results showed that the ‘meat’ context increased arousal ratings for soy sauce and the tendency to consume more tofu relative to the other contexts. Pitch did not influence affective ratings or amounts consumed. We conclude that the multisensory context has the potential to positively affect peoples’ choices and perceptions of plant-based and sustainable food and promote its consumption

Quality of experience in telemeetings and videoconferencing: a comprehensive survey

Telemeetings such as audiovisual conferences or virtual meetings play an increasingly important role in our professional and private lives. For that reason, system developers and service providers will strive for an optimal experience for the user, while at the same time optimizing technical and financial resources. This leads to the discipline of Quality of Experience (QoE), an active field originating from the telecommunication and multimedia engineering domains, that strives for understanding, measuring, and designing the quality experience with multimedia technology. This paper provides the reader with an entry point to the large and still growing field of QoE of telemeetings, by taking a holistic perspective, considering both technical and non-technical aspects, and by focusing on current and near-future services. Addressing both researchers and practitioners, the paper first provides a comprehensive survey of factors and processes that contribute to the QoE of telemeetings, followed by an overview of relevant state-of-the-art methods for QoE assessment. To embed this knowledge into recent technology developments, the paper continues with an overview of current trends, focusing on the field of eXtended Reality (XR) applications for communication purposes. Given the complexity of telemeeting QoE and the current trends, new challenges for a QoE assessment of telemeetings are identified. To overcome these challenges, the paper presents a novel Profile Template for characterizing telemeetings from the holistic perspective endorsed in this paper

Dynamical phenomena in Fibonacci Semiconductor Superlattices

We present a detailed study of the dynamics of electronic wavepackets in Fibonacci semiconductor superlattices, both in flat band conditions and subject to homogeneous electric fields perpendicular to the layers. Coherent propagation of electrons is described by means of a scalar Hamiltonian using the effective-mass approximation. We have found that an initial Gaussian wavepacket is filtered selectively when passing through the superlattice. This means that only those components of the wavepacket whose wavenumber belong to allowed subminibands of the fractal-like energy spectrum can propagate over the entire superlattice. The Fourier pattern of the transmitted part of the wavepacket presents clear evidences of fractality reproducing those of the underlying energy spectrum. This phenomenon persists even in the presence of unintentional disorder due to growth imperfections. Finally, we have demonstrated that periodic coherent-field induced oscillations (Bloch oscillations), which we are able to observe in our simulations of periodic superlattices, are replaced in Fibonacci superlattices by more complex oscillations displaying quasiperiodic signatures, thus sheding more light onto the very peculiar nature of the electronic states in these systems.Comment: 7 pagex, RevTex, 5 Postscript figures. Physical Review B (in press

Технология извлечения структур знаний с использованием аппарата расширенных семантических сетей

В статье рассматривается задача извлечения из текстов естественного языка структур знаний: информационных объектов («именованных сущностей»), их свойств, связей и фактов участия в действиях. Для этих целей разработан инструментарий: язык представления знаний (расширенные семантические сети – РСС) и их обработки (язык преобразования структур – ДЕКЛ). На этой основе созданы технологии, которые обладают следующими особенностями. Из текстов извлекаются не отдельные объекты (именованные сущности), а структуры знаний, представляющие связи объектов и их участие в действиях и событиях. Для извлечения структур знаний разработан уникальный семантико-ориентированный лингвистический процессор (ЛП), осуществляющий глубинный анализ текстов ЕЯ и выявляющий десятки типов объектов вместе с их структурами. Процессор ЛП управляется лингвистическими знаниями, представляющими собой декларативные структуры и обеспечивающие быструю настройку ЛП на предметную область и язык. Основой лингвистических знаний являются правила, обладающие высокой степенью избирательности при выявлении объектов («сущностей»), средствами устранения коллизий при их применении. Это позволяет минимизировать шумы и потери.У статті розглядається задача знайдення у текстах природної мови структур знань: інформаційних об’єктів («іменованих сутностей»), їх якостей зв’язків і фактів участі у діях. Для цих цілей розроблений інструментарій: мова представлення знань (розширені семантичні мережі – РСМ) та їх обробки (мова перетворення структур – ДЕКЛ). На цій основі створені технології, що мають наступні особливості. З тестів виділяються не окремі об’єкти (іменовані сутності), а структури знань, що представляють зв’язки об’єктів та їх участь у діях та подіях. З метою виділення структур знань розроблений винятковий семантико-орієнтований лінгвістичний процесор (ЛП), що здійснює глибинний аналіз текстів ЕЯ та виявляє десятки типів об’єктів разом з їх структурами. Процесор ЛП керується лінгвістичними знаннями, які представляють собою декларативні структури та забезпечують швидке настроювання ЛП на предметну сферу та мову. Основою лінгвістичних знань є правила, що мають високий ступінь вибірковості при виявленні об’єктів («сутностей»), засобами усунення колізій при їхньому використанні. Це дозволяє мінімізувати шуми та втрати.The paper is devoted to the extracting of knowledge structures from the natural language texts, i.e. information objects (“Named Entities”), their features, relationships, and participation in the actions and events. For this purpose, the language used for knowledge representation (extended semantic networks/ESN) and tools for processing (language for structure conversion LSC) are considered. On this base, the new technologies are proposed. These technologies have the following features: extraction from the texts of knowledge structures that represent the links of named entities and their participation in actions and events. For the knowledge extraction the unique semantic-oriented language processor (LP) are designed. Processor LP provides the deep analysis of NL-texts and revealing set of objects together with their structures. Processor LP is controlled by the linguistic knowledge, which are declarative structures (on ESN) and which provides the quick tuning of LP on subject area and language, both Russian and English

Low-frequency monitoring of flare star binary CR Draconis::Long-term electron-cyclotron maser emission

Recently detected coherent low-frequency radio emission from M dwarf systems shares phenomenological similarities with emission produced by magnetospheric processes from the gas giant planets of our Solar System. Such beamed electron-cyclotron maser emission can be driven by a star-planet interaction or a breakdown in co-rotation between a rotating plasma disk and a stellar magnetosphere. Both models suggest that the radio emission could be periodic. Here we present the longest low-frequency interferometric monitoring campaign of an M dwarf system, composed of twenty-one $\approx$8 hour epochs taken in two series of observing blocks separated by a year. We achieved a total on-source time of 6.5 days. We show that the M dwarf binary CR Draconis has a low-frequency 3$\sigma$ detection rate of 90$^{+5}_{-8}$% when a noise floor of $\approx$0.1 mJy is reached, with a median flux density of 0.92 mJy, consistent circularly polarised handedness, and a median circularly polarised fraction of 66%. We resolve three bright radio bursts in dynamic spectra, revealing the brightest is elliptically polarised, confined to 4 MHz of bandwidth centred on 170 MHz, and reaches a flux density of 205 mJy. The burst structure is mottled, indicating it consists of unresolved sub-bursts. Such a structure shares a striking resemblance with the low-frequency emission from Jupiter. We suggest the near-constant detection of high brightness temperature, highly-circularly-polarised radiation that has a consistent circular polarisation handedness implies the emission is produced via the electron-cyclotron maser instability. Optical photometric data reveal the system has a rotation period of 1.984$\pm$0.003 days. We observe no periodicity in the radio data, but the sampling of our radio observations produces a window function that would hide the near two-day signal.Comment: Accepted for publication in A&A, 16 pages, 7 figures, 2 table

Multifractal analysis of the electronic states in the Fibonacci superlattice under weak electric fields

Influence of the weak electric field on the electronic structure of the Fibonacci superlattice is considered. The electric field produces a nonlinear dynamics of the energy spectrum of the aperiodic superlattice. Mechanism of the nonlinearity is explained in terms of energy levels anticrossings. The multifractal formalism is applied to investigate the effect of weak electric field on the statistical properties of electronic eigenfunctions. It is shown that the applied electric field does not remove the multifractal character of the electronic eigenfunctions, and that the singularity spectrum remains non-parabolic, however with a modified shape. Changes of the distances between energy levels of neighbouring eigenstates lead to the changes of the inverse participation ratio of the corresponding eigenfunctions in the weak electric field. It is demonstrated, that the local minima of the inverse participation ratio in the vicinity of the anticrossings correspond to discontinuity of the first derivative of the difference between marginal values of the singularity strength. Analysis of the generalized dimension as a function of the electric field shows that the electric field correlates spatial fluctuations of the neighbouring electronic eigenfunction amplitudes in the vicinity of anticrossings, and the nonlinear character of the scaling exponent confirms multifractality of the corresponding electronic eigenfunctions.Comment: 10 pages, 9 figure