272 research outputs found

    Statistical Study of Phase Relationship Between Magnetic and Plasma Pressures in the Near‐Earth Nightside Magnetosphere Using the THEMIS‐E Satellite

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    Distributions of plasma and magnetic pressures are the basic information to investigate macroscopic dynamics of the Earth's magnetosphere. Several studies have been made on magnetic and plasma pressures and macroscopic plasma instabilities in the magnetosphere. However, correlation between magnetic and plasma pressure variations has not been statistically investigated. In this paper, we analyze the statistical characteristics of the phase relationships between variations of magnetic and plasma pressures at frequencies of 4–15 mHz using 2 years of the THEMIS‐E satellite data in the nightside magnetosphere. Spectral peaks with coherence greater than 0.85 between magnetic and plasma pressures for 1‐hr time segments were selected. The average occurrence rates of the phase relationships are antiphase (within ±10∘ from 180°), 39.75%; in‐phase (within ±10∘ from 0°), 0.73%; and other phases (10–170°), 49.83%. For the other‐phase events, the phase differences are much closer to antiphase rather than to in‐phase. Thus, we conclude that the two pressure variations tend to be antiphase. The antiphase and in‐phase relationships are observed mainly at radial distances outside 8 RE and inside 8 RE, respectively. The high occurrence region of antiphase relationship is in the dawnside during magnetically quiet times and shifts to dusk side at active times defined as Dst <−10 nT. The occurrence rates of the phase relationships do not change significantly depending on the AE and Dst indices, plasma β, and IMF‐Bz. Based on these results, we discuss the correspondence between the phase relationships and the possible magnetohydrodynamic force balances that can produce these phase relationships.ファイル公開:2019-05-01journal articl

    Nothing Lasts Forever: Environmental Discourses on the Collapse of Past Societies

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    The study of the collapse of past societies raises many questions for the theory and practice of archaeology. Interest in collapse extends as well into the natural sciences and environmental and sustainability policy. Despite a range of approaches to collapse, the predominant paradigm is environmental collapse, which I argue obscures recognition of the dynamic role of social processes that lie at the heart of human communities. These environmental discourses, together with confusion over terminology and the concepts of collapse, have created widespread aporia about collapse and resulted in the creation of mixed messages about complex historical and social processes

    Registered Replication Report: Dijksterhuis and van Knippenberg (1998)

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    Dijksterhuis and van Knippenberg (1998) reported that participants primed with a category associated with intelligence ("professor") subsequently performed 13% better on a trivia test than participants primed with a category associated with a lack of intelligence ("soccer hooligans"). In two unpublished replications of this study designed to verify the appropriate testing procedures, Dijksterhuis, van Knippenberg, and Holland observed a smaller difference between conditions (2%-3%) as well as a gender difference: Men showed the effect (9.3% and 7.6%), but women did not (0.3% and -0.3%). The procedure used in those replications served as the basis for this multilab Registered Replication Report. A total of 40 laboratories collected data for this project, and 23 of these laboratories met all inclusion criteria. Here we report the meta-analytic results for those 23 direct replications (total N = 4,493), which tested whether performance on a 30-item general-knowledge trivia task differed between these two priming conditions (results of supplementary analyses of the data from all 40 labs, N = 6,454, are also reported). We observed no overall difference in trivia performance between participants primed with the "professor" category and those primed with the "hooligan" category (0.14%) and no moderation by gender

    Producing mixed linked xylooligosaccharides from red algae biomass through single-step enzymatic hydrolysis

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    BackgroundThe red alga Palmaria palmata is a rich source of sugar compounds, particularly mixed-linkage xylans present in the cell walls of the algae. In contrast to their terrestrial lignocellulosic counterparts, these xylans are more easily accessible. They can be hydrolyzed enzymatically into valuable xylooligosaccharides (XOS), known for their prebiotic, antioxidant, and immunomodulatory properties.ResultsThis study introduces a simplified, one-step enzymatic process utilizing the endo-1,4-beta-xylanase FO15_GH10 that directly hydrolyzes P. palmata biomass to produce XOS, eliminating the need for prior xylan extraction and improving efficiency. The exact structure of the resulting XOS was determined using NMR and MS/MS techniques. In addition, the xylosidase FO17_GH43 can be added to break down all residual 1,4-linked XOS. As a result, only 1,3- and mixed-linkage XOS (degree of polymerization (DP) 2-4) remains under simultaneous increase of the xylose obtained. Using FO15_GH10 alone, it was possible to produce approximately 17.6 (+/- 0.16) % (176 mg) XOS from 1 g of powdered biomass while combining both enzymes resulted in 22.6 (+/- 0.51) % (226 mg) XOS. Further optimization upon upscaling offers the possibility of achieving even greater improvements.ConclusionIn summary, our one-step enzymatic approach offers an efficient and sustainable method for producing XOS directly from P. palmata biomass. This streamlined process overcomes the need for resource-consuming extraction processes. The further characterization of the obtained XOS and the potential to gain solely 1,3- and mixed-linkage XOS is paving the way for future studies on their functional properties

    Geodesy, geophysics and fundamental physics investigations of the BepiColombo mission

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    In preparation for the ESA/JAXA BepiColombo mission to Mercury, thematic working groups had been established for coordinating the activities within the BepiColombo Science Working Team in specific fields. Here we describe the scientific goals of the Geodesy and Geophysics Working Group (GGWG) that aims at addressing fundamental questions regarding Mercury’s internal structure and evolution. This multidisciplinary investigation will also test the gravity laws by using the planet Mercury as a proof mass. The instruments on the Mercury Planetary Orbiter (MPO), which are devoted to accomplishing the GGWG science objectives, include the BepiColombo Laser Altimeter (BELA), the Mercury orbiter radio science experiment (MORE), and the MPO magnetometer (MPO-MAG). The onboard Italian spring accelerometer (ISA) will greatly aid the orbit reconstruction needed by the gravity investigation and laser altimetry. We report the current knowledge on the geophysics, geodesy, and evolution of Mercury after the successful NASA mission MESSENGER and set the prospects for the BepiColombo science investigations based on the latest findings on Mercury’s interior. The MPO spacecraft of the BepiColombo mission will provide extremely accurate measurements of Mercury’s topography, gravity, and magnetic field, extending and improving MESSENGER data coverage, in particular in the southern hemisphere. Furthermore, the dual-spacecraft configuration of the BepiColombo mission with the Mio spacecraft at higher altitudes than the MPO spacecraft will be fundamental for decoupling the internal and external contributions of Mercury’s magnetic field. Thanks to the synergy between the geophysical instrument suite and to the complementary instruments dedicated to the investigations on Mercury’s surface, composition, and environment, the BepiColombo mission is poised to advance our understanding of the interior and evolution of the innermost planet of the solar system

    Scale size estimation and flow pattern recognition around a magnetosheath jet

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    Transient enhancements in the dynamic pressure, so-called magnetosheath jets or simply jets, are abundantly found in the magnetosheath. They travel from the bow shock through the magnetosheath towards the magnetopause. On their way through the magnetosheath, jets disturb the ambient plasma. Multiple studies already investigated their scale size perpendicular to their propagation direction, and almost exclusively in a statistical manner. In this paper, we use multi-point measurements from the Time History of Events and Macroscale Interactions during Substorms (THEMIS) mission to study the passage of a single jet. The method described here allows us to estimate the spatial distribution of the dynamic pressure within the jet. Furthermore, the size perpendicular to the propagation direction can be estimated for different cross sections. In the jet event investigated here, both the dynamic pressure and the perpendicular size increase along the propagation axis from the front part towards the center of the jet and decrease again towards the rear part, but neither monotonically nor symmetrically. We obtain a maximum diameter in the perpendicular direction of about 1 RE and a dynamic pressure of about 6 nPa at the jet center.</p

    Sex in basic research – Concepts in the cardiovascular field

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    Women and men, female and male animals and cells are biologically different, and acknowledgement of this fact is critical to advancing medicine. However, incorporating concepts of sex-specific analysis in basic research is largely neglected, introducing bias into translational findings, clinical concepts and drug development.Research funding agencies recently approached these issues but implementation of policy changes in the scientific community is still limited probably due to deficits in concepts, knowledge and proper methodology. This expert review is based on the EUGenMed project (www.eugenmed.eu) developing a roadmap for implementing sex and gender in biomedical and health research. For sake of clarity and conciseness, examples are mainly taken from the cardiovascular field that may serve as a paradigm for others, since a significant amount of knowledge how sex and estrogen determine the manifestation of many cardiovascular diseases (CVD) has been accumulated. As main concepts for implementation of sex in basic research, the study of primary cell and animals of both sexes, the study of the influence of genetic versus hormonal factors and the analysis of sex chromosomes and sex specific statistics in genome wide association studies (GWAS) are discussed. The review also discusses methodological issues, and analyses strength, weaknesses, opportunities and threats in implementing sex-sensitive aspects into basic research

    Human alveolar progenitors generate dual lineage bronchioalveolar organoids

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    Mechanisms of epithelial renewal in the alveolar compartment remain incompletely understood. To this end, we aimed to characterize alveolar progenitors. Single-cell RNA-sequencing (scRNA-seq) analysis of the HTII-280+/EpCAM+ population from adult human lung revealed subclusters enriched for adult stem cell signature (ASCS) genes. We found that alveolar progenitors in organoid culture in vitro show phenotypic lineage plasticity as they can yield alveolar or bronchial cell-type progeny. The direction of the differentiation is dependent on the presence of the GSK-3β inhibitor, CHIR99021. By RNA-seq profiling of GSK-3β knockdown organoids we identified additional candidate target genes of the inhibitor, among others FOXM1 and EGF. This gives evidence of Wnt pathway independent regulatory mechanisms of alveolar specification. Following influenza A virus (IAV) infection organoids showed a similar response as lung tissue explants which confirms their suitability for studies of sequelae of pathogen-host interaction
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