57 research outputs found

    Seasonal variations in carbon, nitrogen and phosphorus concentrations and C:N:P stoichiometry in different organs of a Larix principis-rupprechtii Mayr. plantation in the Qinling Mountains, China

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    Understanding how concentrations of elements and their stoichiometry change with plant growth and age is critical for predicting plant community responses to environmental change. Weusedlong-term field experiments to explore how the leaf, stem and root carbon (C), nitrogen (N) and phosphorous (P) concentrations and their stoichiometry changed with growth and stand age in a L.principis-rupprechtii Mayr. plantation from 2012–2015 in the Qinling Mountains, China. Our results showed that the C, N and P concentrations and stoichiometric ratios in different tissues of larch stands were affected by stand age, organ type andsampling month and displayed multiple correlations with increased stand age in different growing seasons. Generally, leaf C and N concentrations were greatest in the fast-growing season, but leaf P concentrations were greatest in the early growing season. However, no clear seasonal tendencies in the stem and root C, N and P concentrations were observed with growth. In contrast to N and P, few differences were found in organ-specific C concentrations. Leaf N:P was greatest in the fast-growing season, while C:N and C:P were greatest in the late-growing season. No clear variations were observed in stem and root C:N, C:P andN:Pthroughout the entire growing season, but leaf N:P was less than 14, suggesting that the growth of larch stands was limited by N in our study region. Compared to global plant element concentrations and stoichiometry, the leaves of larch stands had higher C, P, C:NandC:PbutlowerNandN:P,andtherootshadgreater PandC:NbutlowerN,C:Pand N:P. Our study provides baseline information for describing the changes in nutritional elements with plant growth, which will facilitates plantation forest management and restoration, and makes avaluable contribution to the global data pool on leaf nutrition and stoichiometry

    Insights into technical challenges in the field of microplastic pollution through the lens of early career researchers (ECRs) and a proposed pathway forward

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    Early career researchers (ECR) face a series of challenges related to the inherent difficulties of starting their careers. Microplastic (MP) research is a topical field attracting high numbers of ECRs with diverse backgrounds and expertise from a wealth of disciplines including environmental science, biology, chemistry and ecotoxicology. In this perspective the challenges that could hinder scientific, professional, or personal development are explored, as identified by an international network of ECRs, all employed in MP research, that was formed following a bilateral workshop for scientists based in the UK and China. Discussions amongst the network were grouped into four overarching themes of technical challenges: in the field, in the laboratory, in the post data collection phase, and miscellaneous. The three key areas of representativeness, access to appropriate resources, training, and clean labs, and the use of databases and comparability, as well as the overarching constraint of available time were identified as the source of the majority of challenges. A set of recommendations for pathways forward are proposed based on the principles of research openness, access to information and training, and widening collaborations. ECRs have great capacity to promote research excellence in the field of MPs and elsewhere, when provided with appropriate opportunities and suitable support

    Insights into technical challenges in the field of microplastic pollution through the lens of early career researchers (ECRs) and a proposed pathway forward

    Get PDF
    Early career researchers (ECR) face a series of challenges related to the inherent difficulties of starting their careers. Microplastic (MP) research is a topical field attracting high numbers of ECRs with diverse backgrounds and expertise from a wealth of disciplines including environmental science, biology, chemistry and ecotoxicology. In this perspective the challenges that could hinder scientific, professional, or personal development are explored, as identified by an international network of ECRs, all employed in MP research, that was formed following a bilateral workshop for scientists based in the UK and China. Discussions amongst the network were grouped into four overarching themes of technical challenges: in the field, in the laboratory, in the post data collection phase, and miscellaneous. The three key areas of representativeness, access t

    Evidence-based PET for thoracic tumours

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    AbstractFluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) is a robust imaging tool that is currently used in daily clinical practice for the evaluation of thoracic malignancies. This chapter provides an overview of the current evidence-based data on the usefulness of PET/CT for the evaluation of patients with thoracic tumours including lung cancer, pleural and thymic tumours, and esophageal cancer

    SoccerNet 2023 Challenges Results

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    peer reviewedThe SoccerNet 2023 challenges were the third annual video understanding challenges organized by the SoccerNet team. For this third edition, the challenges were composed of seven vision-based tasks split into three main themes. The first theme, broadcast video understanding, is composed of three high-level tasks related to describing events occurring in the video broadcasts: (1) action spotting, focusing on retrieving all timestamps related to global actions in soccer, (2) ball action spotting, focusing on retrieving all timestamps related to the soccer ball change of state, and (3) dense video captioning, focusing on describing the broadcast with natural language and anchored timestamps. The second theme, field understanding, relates to the single task of (4) camera calibration, focusing on retrieving the intrinsic and extrinsic camera parameters from images. The third and last theme, player understanding, is composed of three low-level tasks related to extracting information about the players: (5) re-identification, focusing on retrieving the same players across multiple views, (6) multiple object tracking, focusing on tracking players and the ball through unedited video streams, and (7) jersey number recognition, focusing on recognizing the jersey number of players from tracklets. Compared to the previous editions of the SoccerNet challenges, tasks (2-3-7) are novel, including new annotations and data, task (4) was enhanced with more data and annotations, and task (6) now focuses on end-to-end approaches. More information on the tasks, challenges, and leaderboards are available on https://www.soccer-net.org. Baselines and development kits can be found on https://github.com/SoccerNet

    Micropatterned chemistry and structure in layered bionanocomposites

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    The quest for humankind’s increased capabilities in gathering information, analyzing data, and controlling our surrounding environment is leading to a proliferation of connected physical objects that can sense, compute, and communicate. Conventional classes of electronic materials such as metals and semiconductors cannot meet this new demand alone due to challenges in scale, and ability to function in new use-environments such as on clothing, on skin, and in the human body. In this research, 1D biopolymers (silk fibroin, cellulose nanocrystals) and 2D synthetic components (functionalized graphenes) are assembled into bio-derived nanocomposite papers. Through post-processing conversion of geometry and surface chemistry at the microscale, these biopapers are transformed into a platform for flexible and stretchable electronics for diverse applications including stretchable wiring, energy harvesting, energy storage, and haptic sensing. The key to realizing these applications is leveraging the intrinsic properties of nanoscale components through the controlled, localized application of annealing, cutting, printing and stenciling. Elements of directed microstructural design include patterned voids to generate algorithmic pop-up deformations, partial cuts to inhibit metastable buckling, conductive traces to enable sensory circuits, and interdigitated electrodes to support double layer capacitance. The set of techniques and the structure-property relations explored in this work can serve as a framework for understanding microstructural manipulation that is generalized across layered nanocomposites.Ph.D

    AN INVESTIGATION ON WINDMILL PALM LEAF SHEATH FIBER POWDER-BASED ACTIVATED CARBON FOR DYE ADSORPTION

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    Windmill palm sheath fiber (WPF) is an abundant agricultural by-product and useful resource. To increase its valuable qualities and usefulness, we proposed to prepare WPF-based activated carbon (WPFAC) as a novel adsorbent for adsorbing methylene blue (MB), with the specific aims for pollution treatment. The porous features of WPFAC were assessed based on nitrogen adsorption, and the adsorption capacity was studied by investigating the effect parameters of contact time, initial concentration, pH and temperature. Research results show a combination microporous and mesoporous structure of WPFAC with BET surface of 668.81 m2/g. WPFAC exhibits excellent adsorbing performance, and the maximum monolayer adsorption capacity is up to 51.78 times higher than other absorbents. Meanwhile, the adsorption capacity increased accordingly as the parameters increase. For better understanding the adsorption behavior, isotherms, kinetics and thermodynamic were studied by using the equilibrium data. Investigation results illustrated the equilibrium data were well consistent with the Langmuir isotherm, with a maximum monolayer adsorption capacity of 253.16, 289.85, and 303.95 mg/g at 30, 40, and 50 °C, respectively. The adsorption kinetics followed the pseudo-second-order kinetic model. Thermodynamic parameters: standard enthalpy (ΔH0), standard entropy (ΔS0), and standard free energy (ΔG0) indicated an endothermic and spontaneous absorbing process. WPFAC is a promising material which has high utility values for its amazing adsorption capacity

    All-optical controllable electromagnetically induced transparency in coupled silica microbottle cavities

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    An all-optical control scheme of electromagnetically induced transparency (EIT) based on two coupled silica microbottle cavities coated with iron oxide nanoparticles is proposed and experimentally demonstrated. The specially designed and fabricated silica microbottle cavity with a short and spherical end, which is coated with iron oxide nanoparticles, possesses a quality (Q) factor of 1.39×108 and large all-optical tunability in a range of 282.32 GHz (2.25 nm) arising from the strong photothermal effect of the nanoparticles. Based on two coupled silica microbottle cavities, we achieve the EIT spectrum with a transparency window bandwidth of 2.3 MHz. The transparency window can be flexibly controlled by tuning the resonant frequency of the higher-Q microcavity. Besides, by tuning the resonant frequencies of the two microcavities separately, the whole EIT spectrum can be shifted with a range of 71.52 GHz, to the best of our knowledge, for the first time. Based on this scheme, we have realized all-optical and independent control of the transparency window and the whole EIT spectrum. We believe this work has great potential in applications such as light storage, optical sensing, and quantum optics
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