493 research outputs found

    Muon spin spectroscopy: magnetism, soft matter and the bridge between the two

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    LS would like to acknowledge financial support from the Swiss National Science Foundation, grant numbers PBFRP2-138632 and PBFRP2-142820. AD would like to acknowledge financial support from the UK Engineering and Physical Sciences Research Council, grant number EP/G054568/1, the European Union Seventh Framework Programme project NMP3-SL- 2011-263104 ‘HINTS’ and the European Research Council project ‘Muon Spin Spectroscopy of Excited States (MuSES)’ proposal number 307593LS would like to acknowledge financial support from the Swiss National Science Foundation, grant numbers PBFRP2-138632 and PBFRP2-142820. AD would like to acknowledge financial support from the UK Engineering and Physical Sciences Research Council, grant number EP/G054568/1, the European Union Seventh Framework Programme project NMP3-SL- 2011-263104 ‘HINTS’ and the European Research Council project ‘Muon Spin Spectroscopy of Excited States (MuSES)’ proposal number 307593LS would like to acknowledge financial support from the Swiss National Science Foundation, grant numbers PBFRP2-138632 and PBFRP2-142820. AD would like to acknowledge financial support from the UK Engineering and Physical Sciences Research Council, grant number EP/G054568/1, the European Union Seventh Framework Programme project NMP3-SL- 2011-263104 ‘HINTS’ and the European Research Council project ‘Muon Spin Spectroscopy of Excited States (MuSES)’ proposal number 30759

    Refurbishment and testing of the integrated waste management system Final report, Dec. 1968 - Aug. 1969

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    Refurbishment and testing of integrated waste management system for manned space fligh

    Electron spin relaxation in organic semiconductors probed through muSR

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    Muon spin spectroscopy and in particular the avoided level crossing technique is introduced, with the aim of showing it as a very sensitive local probe for electron spin relaxation in organic semiconductors. Avoided level crossing data on TMS-pentacene at different temperatures are presented, and they are analysed to extract the electron spin relaxation rate, that is shown to increase on increasing the temperature from 0.02 MHz to 0.33 MHz at 3 K and 300 K respectively.Comment: International Conference TSN2010 "Trends in spintronics and nanomagnetism

    On the discrimination of multiple phytoplankton groups from light absorption spectra of assemblages with mixed taxonomic composition and variable light conditions

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    According to recommendations of the international community of phytoplankton functional type algorithm developers, a set of experiments on marine algal cultures was conducted to (1) investigate uncertainties and limits in phytoplankton group discrimination from hyperspectral light absorption properties of assemblages with mixed taxonomic composition, and (2) evaluate the extent to which modifications of the absorption spectral features due to variable light conditions affect the optical discrimination of phytoplankton. Results showed that spectral absorption signatures of multiple species can be extracted from mixed assemblages, even at low relative contributions. Errors in retrieved pigment abundances are, however, influenced by the co-occurrence of species with similar spectral features. Plasticity of absorption spectra due to changes in light conditions weakly affects interspecific differences, with errors <21% for retrievals of pigment concentrations from mixed assemblages

    Where are the drought tolerant crops? An assessment of more than two decades of plant biotechnology effort in crop improvement

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    Since the dawn of modern biotechnology public and private enterprise have pursued the development of a new breed of drought tolerant crop products. After more than 20 years of research and investment only a few such products have reached the market. This is due to several technical and market constraints. The technical challenges include the difficulty in defining tractable single-gene trait development strategies, the logistics of moving traits from initial to commercial genetic backgrounds, and the disconnect between conditions in farmer’s fields and controlled environments. Market constraints include the significant difficulty, and associated costs, in obtaining access to markets around the world. Advances in the biology of plant water management, including response to water deficit reveal new opportunities to improve crop response to water deficit and new genome-based tools promise to usher in the next era of crop improvement. As biotechnology looks to improve crop productivity under drought conditions, the environmental and food security advantages will influence public perception and shift the debate toward benefits rather than risks

    Prevalence of molar incisor hypomineralization among school children in Rome, Italy

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    Molar incisor hypomineralization (MIH) is a highly prevalent condition associated with increased caries experience, dental pain and treatment need. Aim of this study was to determine the prevalence and severity of MIH in a group of 7–8 years old primary school children living in Rome, Italy; and to assess the association with caries experience and possible perinatal risk factors. A survey has been conducted in the city of Rome, between April 2019 and March 2020 with a total of 49 primary schools and 176 2nd grade primary school classes and a total of 3611 children being involved. Of these, a subset of 346 children of 21 primary schools was selected for the epidemiological investigation. The prevalence of MIH was of 18.2%, with girls showing twice the probability of being subject to a mild-severe condition. Molar location was present in 71.4%, while location on both molar plus incisor was present in 28.6% of cases. The mean DMFT was 0.44 ± 0.78, “D” was 0.17 ± 0.58; the mean dmft was 1.7 ± 2.56, “d” was 1.32 ± 2.21. Female gender, caries experience, insufficient oral hygiene were risk factors. The incidence of MIH is increasing in the pediatric population. Knowledge about diagnosis and treatment options should be disseminated among dental professionals.publishedVersio

    Niche differentiation is spatially and temporally regulated in the rhizosphere.

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    The rhizosphere is a hotspot for microbial carbon transformations, and is the entry point for root polysaccharides and polymeric carbohydrates that are important precursors to soil organic matter (SOM). However, the ecological mechanisms that underpin rhizosphere carbohydrate depolymerization are poorly understood. Using Avena fatua, a common annual grass, we analyzed time-resolved metatranscriptomes to compare microbial functions in rhizosphere, detritusphere, and combined rhizosphere-detritusphere habitats. Transcripts were binned using a unique reference database generated from soil isolate genomes, single-cell amplified genomes, metagenomes, and stable isotope probing metagenomes. While soil habitat significantly affected both community composition and overall gene expression, the succession of microbial functions occurred at a faster time scale than compositional changes. Using hierarchical clustering of upregulated decomposition genes, we identified four distinct microbial guilds populated by taxa whose functional succession patterns suggest specialization for substrates provided by fresh growing roots, decaying root detritus, the combination of live and decaying root biomass, or aging root material. Carbohydrate depolymerization genes were consistently upregulated in the rhizosphere, and both taxonomic and functional diversity were highest in the combined rhizosphere-detritusphere, suggesting coexistence of rhizosphere guilds is facilitated by niche differentiation. Metatranscriptome-defined guilds provide a framework to model rhizosphere succession and its consequences for soil carbon cycling

    VFDB 2012 update: toward the genetic diversity and molecular evolution of bacterial virulence factors

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    The virulence factor database (VFDB, http://www.mgc.ac.cn/VFs/) has served as a comprehensive repository of bacterial virulence factors (VFs) for >7 years. Bacterial virulence is an exciting and dynamic field, due to the availability of complete sequences of bacterial genomes and increasing sophisticated technologies for manipulating bacteria and bacterial genomes. The intricacy of virulence mechanisms offers a challenge, and there exists a clear need to decipher the ‘language’ used by VFs more effectively. In this article, we present the recent major updates of VFDB in an attempt to summarize some of the most important virulence mechanisms by comparing different compositions and organizations of VFs from various bacterial pathogens, identifying core components and phylogenetic clades and shedding new light on the forces that shape the evolutionary history of bacterial pathogenesis. In addition, the 2012 release of VFDB provides an improved user interface

    Importance of Spin-Orbit Interaction for the Electron Spin Relaxation in Organic Semiconductors

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    Despite the great interest organic spintronics has recently attracted, there is only a partial understanding of the fundamental physics behind electron spin relaxation in organic semiconductors. Mechanisms based on hyperfine interaction have been demonstrated, but the role of the spin-orbit interaction remains elusive. Here, we report muon spin spectroscopy and time-resolved photoluminescence measurements on two series of molecular semiconductors in which the strength of the spin-orbit interaction has been systematically modified with a targeted chemical substitution of different atoms at a particular molecular site. We find that the spin-orbit interaction is a significant source of electron spin relaxation in these materials
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