505 research outputs found

    Vacancy defects in epitaxial thin film CuGaSe2 and CuInSe2

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    Epitaxial thin film CuGaSe2 and CuInSe2 samples grown on GaAs substrates with varying [Cu]/[Ga,In] ratios were studied using positron annihilation Doppler-broadening spectroscopy and were compared to bulk crystals. We find both Cu monovacancies and Cu-Se divacancies in CuInSe2, whereas, in CuGaSe2, the only observed vacancy defect is the Cu-Se divacancy.Peer reviewe

    Warmer spring alleviated the impacts of 2018 European summer heatwave and drought on vegetation photosynthesis

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    Future projections of climate extremes are expected to become more frequent. Parts of Europe experienced an extensive heatwave and drought during 2018. However, its impacts on terrestrial carbon cycle remain elusive. Here we investigated the vegetation responses to the heatwave and drought during 2018 based on satellite solar-induced chlorophyll fluorescence (SIF) and near-infrared reflectance (NIRv) data, which were used to estimate gross primary productivity (GPP). Results showed that there were no significant (p= 0.60) reductions in GPP across most of Europe during April-August of 2018. The higher temperatures in spring enhanced vegetation GPP, largely alleviated the negative impacts of heatwave and drought on vegetation photosynthesis during the subsequent summer, which resulted in evident compensation effects. Concurrently, warmer spring also had lagged effects by diminishing soil moisture, accompanied by scarce precipitation, leading to water stress on plant growth during summer. This observation-based study highlights the need for more considerations of seasonal compensation and lagged effects on the interactions between climate extreme events and biosphere.Peer reviewe

    Teratoma formation of human embryonic stem cells in three-dimensional perfusion culture bioreactors

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    Teratoma formation in mice is today the most stringent test for pluripotency that is available for human pluripotent cells, as chimera formation and tetraploid complementation cannot be performed with human cells. The teratoma assay could also be applied for assessing the safety of human pluripotent cell-derived cell populations intended for therapeutic applications. In our study we examined the spontaneous differentiation behaviour of human embryonic stem cells (hESCs) in a perfused 3D multi-compartment bioreactor system and compared it with differentiation of hESCs and human induced pluripotent cells (hiPSCs) cultured in vitro as embryoid bodies and in vivo in an experimental mouse model of teratoma formation. Results from biochemical, histological/immunohistological and ultrastuctural analyses revealed that hESCs cultured in bioreactors formed tissue-like structures containing derivatives of all three germ layers. Comparison with embryoid bodies and the teratomas revealed a high degree of similarity of the tissues formed in the bioreactor to these in the teratomas at the histological as well as transcriptional level, as detected by comparative whole-genome RNA expression profiling. The 3D culture system represents a novel in vitro model that permits stable long-term cultivation, spontaneous multi-lineage differentiation and tissue formation of pluripotent cells that is comparable to in vivo differentiation. Such a model is of interest, e.g. for the development of novel cell differentiation strategies. In addition, the 3D in vitro model could be used for teratoma studies and pluripotency assays in a fully defined, controlled environment, alternatively to in vivo mouse models. Copyright (c) 2012 John Wiley & Sons, Ltd

    Towards integration of research and monitoring at forest ecosystems in Europe

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    Aim of study: The main aim of the work was to summarize availability, quality and comparability of on-going European Research and Monitoring Networks (ERMN), based on the results of a COST FP0903 Action questionnaire carried out in September 2010 and May 2012. Area of study: The COST Action FP0903 involves 29 European countries and 4 non-COST institutions from USA, Morocco and Tunisia. In this study, the total of 22 replies to the questionnaire from 18 countries were included. Materials and methods: Based on the feedback from the Action FP0903 countries, the most popular European Networks were identified. Thereafter, the access to the network database, available quality assurance/quality control procedures and publication were described. Finally, the so-called “Supersites” concept, defined as a “highly instrumented research infrastructure, for both research and monitoring of soil-plant-atmosphere interactions” was discussed. Main results: The result of the survey indicate that the vast majority of the Action FP0903 countries participate in the International Cooperative Programme on Assessment and Monitoring of Air Pollution Effects on Forest (ICP Forest). The multi-disciplinary International Cooperative Programme on Integrated Monitoring of Air Pollution Effects on Ecosystems (ICPIM) is the second most widespread forest programme. Research highlights: To fully understand biochemical cycles in forest ecosystems, long-term monitoring is needed. Hence, a network of “Supersites”, is proposed. The application of the above infrastructure can be an effective way to attain a better integration of research and monitoring networks at forest sites in Europ

    Microbiota of human breast tissue

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    In recent years, a greater appreciation for the microbes inhabiting human body sites has emerged. In the female mammary gland, milk has been shown to contain bacterial species, ostensibly reaching the ducts from the skin. We decided to investigate whether there is a microbiome within the mammary tissue. Using 16S rRNA sequencing and culture, we analyzed breast tissue from 81 women with and without cancer in Canada and Ireland. A diverse population of bacteria was detected within tissue collected from sites all around the breast in women aged 18 to 90, not all of whom had a history of lactation. The principal phylum was Proteobacteria. The most abundant taxa in the Canadian samples were Bacillus (11.4%), Acinetobacter (10.0%), Enterobacteriaceae (8.3%), Pseudomonas (6.5%), Staphylococcus (6.5%), Propionibacterium (5.8%), Comamonadaceae (5.7%), Gammaproteobacteria (5.0%), and Prevotella (5.0%). In the Irish samples the most abundant taxa were Enterobacteriaceae (30.8%), Staphylococcus (12.7%), Listeria welshimeri (12.1%), Propionibacterium (10.1%), and Pseudomonas (5.3%). None of the subjects had signs or symptoms of infection, but the presence of viable bacteria was confirmed in some samples by culture. The extent to which these organisms play a role in health or disease remains to be determined. © 2014, American Society for Microbiology

    Education for sustainable development: A study in adolescent perception changes towards sustainability following a strategic planning-based intervention-the young persons' plan for the planet program

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    © 2019 by the authors. In 2016, the United Nations (UN) launched the 17 Sustainable Development Goals (SDGs) as a framework for sustainable development and a sustainable future. However, the global challenge has been to engage, connect, and empower communities, particularly young people, to both understand and deliver the 17 SDGs. In this study, we show the benefit of a strategic planning-based experiential learning tool, the Young Persons' Plan for the Planet (YPPP) Program, to improve the underlying competencies of Australian and Mauritian adolescents in increasing understanding and delivering the SDGs. The study was conducted with 300 middle to senior high school students, in 25 schools throughout Australia and Mauritius, over an 18-month period. The intervention included the development of research, strategic planning, management, STEM (Science Technology, Engineering, Maths) and global competency skills in the students, to enable them to build and deliver regional and national SDG plans. Research methods included pre- and post-intervention testing of the attitudes of these students to sustainable development outcomes and compared these attitudes to subsets of scientists and the Australian national population. Our results, from both qualitative and quantitative evidence, demonstrate significant improvements in these adolescents' appreciation of, and attitudes towards, the SDGs and sustainable outcomes, across a range of key parameters. The results from the 76 students who attended the International Conference in Mauritius in December 2018 demonstrate significant improvements in mean levels of understanding, and attitudes of the students towards the SDGs awareness (+85%), understanding/engagement (+75%), motivation (+57%), and action orientation/empowerment (+66%). These changes were tested across a range of socio-demographic, geographic, and cultural parameters, with consistent results. These findings have significant implications for the challenge of sustainable education and achieving community engagement and action towards the SDGs in Australia and Mauritius, particularly for young people. As the intervention can be replicated and scaled, the findings also highlight the opportunity to extend both the research and this type of experiential learning intervention across both broader geographies and other generation and community segments

    High-confidence glycosome proteome for procyclic form <em>Trypanosoma brucei</em> by epitope-tag organelle enrichment and SILAC proteomics

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    The glycosome of the pathogenic African trypanosome Trypanosoma brucei is a specialized peroxisome that contains most of the enzymes of glycolysis and several other metabolic and catabolic pathways. The contents and transporters of this membrane-bounded organelle are of considerable interest as potential drug targets. Here we use epitope tagging, magnetic bead enrichment, and SILAC quantitative proteomics to determine a high-confidence glycosome proteome for the procyclic life cycle stage of the parasite using isotope ratios to discriminate glycosomal from mitochondrial and other contaminating proteins. The data confirm the presence of several previously demonstrated and suggested pathways in the organelle and identify previously unanticipated activities, such as protein phosphatases. The implications of the findings are discussed

    Galaxy Counterparts of metal-rich Damped Lyman-alpha Absorbers - I: The case of the z=2.35 DLA towards Q2222-0946

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    We have initiated a survey using the newly commissioned X-shooter spectrograph to target candidate relatively metal-rich damped Lyman-alpha absorbers (DLAs). The spectral coverage of X-shooter allows us to search for not only Lyman-alpha emission, but also rest-frame optical emission lines. We have chosen DLAs where the strongest rest-frame optical lines ([OII], [OIII], Hbeta and Halpha) fall in the NIR atmospheric transmission bands. In this first paper resulting from the survey, we report on the discovery of the galaxy counterpart of the z_abs = 2.354 DLA towards the z=2.926 quasar Q2222$-0946. This DLA is amongst the most metal-rich z>2 DLAs studied so far at comparable redshifts and there is evidence for substantial depletion of refractory elements onto dust grains. We measure metallicities from ZnII, SiII, NiII, MnII and FeII of -0.46+/-0.07, -0.51+/-0.06, -0.85+/-0.06, -1.23+/-0.06, and -0.99+/-0.06, respectively. The galaxy is detected in the Lyman-alpha, [OIII] lambda4959,5007 Halpha emission lines at an impact parameter of about 0.8 arcsec (6 kpc at z_abs = 2.354). We infer a star-formation rate of 10 M_sun yr^-1, which is a lower limit due to the possibility of slit-loss. Compared to the recently determined Halpha luminosity function for z=2.2 galaxies the DLA-galaxy counterpart has a luminosity of L~0.1L^*_Halpha. The emission-line ratios are 4.0 (Lyalpha/Halpha) and 1.2 ([OIII]/Halpha). The Lyalpha line shows clear evidence for resonant scattering effects, namely an asymmetric, redshifted (relative to the systemic redshift) component and a much weaker blueshifted component. The fact that the blueshifted component is relatively weak indicates the presence of a galactic wind. The properties of the galaxy counterpart of this DLA is consistent with the prediction that metal-rich DLAs are associated with the most luminous of the DLA-galaxy counterparts.Comment: 9 pages, 7 figures. Accepted for publication in MNRA
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