414 research outputs found

    Evaluation of Cathode Gas Composition and Temperature Influences on Alkaline Anion Exchange Membrane Fuel Cell (AAEMFC) Performance

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    The effects of different temperatures (55, 65, 75 and 85 °C) and cathode gas compositions (O2, synthetic air, air and 90% synthetic air+10% CO2) on alkaline anion exchange membrane fuel cell (AAEMFC) were evaluated. Membrane electrode assemblies (MEA) were fabricated using commercial anion exchange membrane (AEM) in OH- form and Pt catalyst. Polarization curves and voltage responses during constant current were performed in order to describe the influences of temperature and gas composition on the AAEMFC performance. The experimental results showed that the fuel cell performance increases with elevating temperatures for all applied gas compositions. Highest power density of 34.7 mW cm-2 was achieved for pure O2 as cathode feed. A decrease to 20.3 mW cm-2 was observed when cathode gas composition was changed to synthetic air due to reduction of the O2 partial pressure. The presence of CO2 in atmospheric air applied to the cathode stream caused a further drop of the maximum power density to 15.2 mW cm-2 driven by neutralization of OH- ions with CO2

    Global assessment of manure management policies and practices

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    In 2014 an assessment of livestock manure policies was performed in 34 countries in Asia, Africa and Latin America, followed by an in-depth assessment of manure management practices in Bangladesh, Viet Nam, Ethiopia, Malawi, Argentina and Costa Rica. The assessments revealed the key barriers for improving integrated manure management and identified six opportunities for actual practice changes to improve manure related policies as well as farm practices with the overall objective of improving food security while mitigating methane emissions at the same tim

    Hadronic production of bottom-squark pairs with electroweak contributions

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    We present the complete computation of the tree-level and the next-to-leading order electroweak contributions to bottom-squark pair production at the LHC. The computation is performed within the minimal supersymmetric extension of the Standard Model. We discuss the numerical impact of these contributions in several supersymmetric scenarios.Comment: 33 pages, v2: preprint numbers correcte

    Photon Radiation with MadDipole

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    We present the automation of a subtraction method for photon radiation using the dipole formalism within the MadGraph framework. The subtraction terms are implemented both in dimensional regularization and mass regularization for massless and massive cases and non-collinear-safe observables are accounted for.Comment: 23 pages, 2 figures, minor additions, references added, version published in JHE

    NLL soft and Coulomb resummation for squark and gluino production at the LHC

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    We present predictions of the total cross sections for pair production of squarks and gluinos at the LHC, including the stop-antistop production process. Our calculation supplements full fixed-order NLO predictions with resummation of threshold logarithms and Coulomb singularities at next-to-leading logarithmic (NLL) accuracy, including bound-state effects. The numerical effect of higher-order Coulomb terms can be as big or larger than that of soft-gluon corrections. For a selection of benchmark points accessible with data from the 2010-2012 LHC runs, resummation leads to an enhancement of the total inclusive squark and gluino production cross section in the 15-30 % range. For individual production processes of gluinos, the corrections can be much larger. The theoretical uncertainty in the prediction of the hard-scattering cross sections is typically reduced to the 10 % level.Comment: 45 pages, 16 Figures, LaTex. v2: published version. Grids with numerical results for the NLL cross sections for squark and gluino production at the 7/8 TeV LHC are included in the submission and are also available at http://omnibus.uni-freiburg.de/~cs1010/susy.htm

    Hadronic production of squark-squark pairs: The electroweak contributions

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    We compute the electroweak (EW) contributions to squark--squark pair production processes at the LHC within the framework of the Minimal Supersymmetric Standard Model (MSSM). Both tree-level EW contributions, of O(alpha_s alpha + alpha^2), and next-to-leading order (NLO) EW corrections, of O(alpha_s^2 alpha), are calculated. Depending on the flavor and chirality of the produced quarks, many interferences between EW-mediated and QCD-mediated diagrams give non-zero contributions at tree-level and NLO. We discuss the computational techniques and present an extensive numerical analysis for inclusive squark--squark production as well as for subsets and single processes. While the tree-level EW contributions to the integrated cross sections can reach the 20% level, the NLO EW corrections typically lower the LO prediction by a few percent.Comment: 36 pages, 18 figure

    Soil water retention and hydraulic conductivity measured in a wide saturation range

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    Soil hydraulic properties (SHPs), particularly soil water retention capacity and hydraulic conductivity of unsaturated soils, are among the key properties that determine the hydrological functioning of terrestrial systems. Some large collections of SHPs, such as the UNSODA and HYPRES databases, have already existed for more than 2 decades. They have provided an essential basis for many studies related to the critical zone. Today, sample-based SHPs can be determined in a wider saturation range and with higher resolution by combining some recently developed laboratory methods. We provide 572 high-quality SHP data sets from undisturbed, mostly central European samples covering a wide range of soil texture, bulk density and organic carbon content. A consistent and rigorous quality filtering ensures that only trustworthy data sets are included. The data collection contains (i) SHP data, which consist of soil water retention and hydraulic conductivity data, determined by the evaporation method and supplemented by retention data obtained by the dewpoint method and saturated conductivity measurements; (ii) basic soil data, which consist of particle size distribution determined by sedimentation analysis and wet sieving, bulk density and organic carbon content; and (iii) metadata, which include the coordinates of the sampling locations. In addition, for each data set, we provide soil hydraulic parameters for the widely used van Genuchten–Mualem model and for the more advanced Peters–Durner–Iden model. The data were originally collected to develop and test SHP models and associated pedotransfer functions. However, we expect that they will be very valuable for various other purposes such as simulation studies or correlation analyses of different soil properties to study their causal relationships. The data are available at https://doi.org/10.5880/fidgeo.2023.012 (Hohenbrink et al., 2023).</p

    Expression of Foxp3 in colorectal cancer but not in Treg cells correlates with disease progression in patients with colorectal cancer

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    Background: Regulatory T cells (Treg) expressing the transcription factor forkhead-box protein P3 (Foxp3) have been identified to counteract anti-tumor immune responses during tumor progression. Besides, Foxp3 presentation by cancer cells itself may also allow them to evade from effector T-cell responses, resulting in a survival benefit of the tumor. For colorectal cancer (CRC) the clinical relevance of Foxp3 has not been evaluated in detail. Therefore the aim of this study was to study its impact in colorectal cancer (CRC). Methods and Findings: Gene and protein analysis of tumor tissues from patients with CRC was performed to quantify the expression of Foxp3 in tumor infiltrating Treg and colon cancer cells. The results were correlated with clinicopathological parameters and patients overall survival. Serial morphological analysis demonstrated Foxp3 to be expressed in cancer cells. High Foxp3 expression of the cancer cells was associated with poor prognosis compared to patients with low Foxp3 expression. In contrast, low and high Foxp3 level in tumor infiltrating Treg cells demonstrated no significant differences in overall patient survival. Conclusions: Our findings strongly suggest that Foxp3 expression mediated by cancer cells rather than by Treg cells contribute to disease progression

    Experiencing mindfulness meditation—a client narrative perspective

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    The study was based on the non-participant involvement of the researcher in four six-to-eight weeks' mindfulness meditation training courses led by chartered psychologists. The participants suffered from stress/sleeplessness, depression or agoraphobia in the presented cases. They were selected on the basis of recommendations by the psychologist who was the course instructor, who described them as positive and suitable. The participants wrote diaries on a weekly basis, and they were interviewed at the beginning, middle and end of the course. An in-depth analysis of three individual cases will be presented in the form of narratives constructed from their own words. The narratives demonstrate the unique and embodied changes of the individual participant's experiences during the training course. The purpose was to illustrate richly what happens and how changes happen during these weeks of learning and practicing mindfulness meditation. It is not the intention to give evidence about the effectiveness of mindfulness meditation in general, but to present the whats and hows of cases where mindfulness meditation appears to improve quality of life, health and well-being
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