721 research outputs found

    Science Education for Citizenship and a Sustainable Future

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    In this article Jerry Wellington argues very strongly in favour of the role of science in citizenship education. He emphasizes the need for knowledge, skills and action and suggests areas and ways in which pupils can be engaged in the struggle for a sustainable future where interdependence and interconnectedness mesh well with notions of equity and justice

    Bringing toilets back to Kumasi's compound houses: landlord and tenant behaviours and motivators

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    In the low-income urban communities of Kumasi, Ghana, a large part of the population live in compound housing, where they often share the same living space with more than 20 tenants. Partly resulting from the high prevalence of public toilets in the city, the vast majority of these tenants have no access to ‘inhouse’ sanitation. Led by the Kumasi Metropolitan Assembly, a five-year strategy is being prepared to promote increased adoption, access, usage and maintenance of compound toilets in Kumasi’s lowincome communities. This paper shares the results of a desk and field-based study commissioned to inform the strategy: among the key challenges to be confronted are the clarification of responsibilities between landlords and tenants with regards to financing sanitation improvements, and the need to motivate landlords - at the hub of compound level sanitation governance - to improve the situation for the betterment of their tenants

    Large Dust Aerosol Sizes Seen During the 2018 Martian Global Dust Event by the Curiosity Rover

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    Mars’ atmosphere typically supports dust aerosol with an effective radius near 1.5 μm, varying from ~1 μm during low dust times near northern summer solstice to ~2 μm during higher dust times in southern spring and summer. After global dust events, size variations outside this range have not previously been observed. We report on imaging and spectral observations by the Curiosity rover through the 2018 global dust event. These observations show that the dust effective radius was seasonally normal prior to the local onset of increased opacity, increased rapidly above 4 μm with increasing opacity, remained above 3 μm over a period of ~50 Martian solar days, then returned to seasonal values before the opacity did so. This demonstrates lifting and regionalâ scale transport of a dust population ~3 times the size of typical dust aerosol.Plain Language SummaryDuring the global dust storm of 2018, the Curiosity rover measured the variation of atmospheric dust over time. During the onset of the dust storm, typical Martian dust was enhanced by much larger particles that were freshly lifted off the surface in distant storms and then carried to the rover site at Gale crater. The larger dust particles persisted for weeks, but fell out of the atmosphere faster than the typical dust as normal conditions were restored.Key PointsThe Curiosity rover observed dust aerosol size variations through the 2018 global dust eventThe average dust radius increased above 4 μm, more than double the largest sizes previously seen with Curiosity’s instrumentsThe observations demonstrate the lifting and regionalâ scale transport of dust significantly larger than typical dust aerosolPeer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/151856/1/grl59493.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/151856/2/grl59493_am.pd

    Meeting report : 1st international functional metagenomics workshop May 7–8, 2012, St. Jacobs, Ontario, Canada

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    This report summarizes the events of the 1st International Functional Metagenomics Workshop. The workshop was held on May 7 and 8 in St. Jacobs, Ontario, Canada and was focused on building a core international functional metagenomics community, exploring strategic research areas, and identifying opportunities for future collaboration and funding. The workshop was initiated by researchers at the University of Waterloo with support from the Ontario Genomics Institute (OGI), Natural Sciences and Engineering Research Council of Canada (NSERC) and the University of Waterloo

    Validity and worth in the science curriculum: learning school science outside the laboratory

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    It is widely acknowledged that there are problems with school science in many developed countries of the world. Such problems manifest themselves in a progressive decline in pupil enthusiasm for school science across the secondary age range and the fact that fewer students are choosing to study the physical sciences at higher levels and as careers. Responses to these developments have included proposals to reform the curriculum, pedagogy and the nature of pupil discussion in science lessons. We support such changes but argue from a consideration of the aims of science education that secondary school science is too rooted in the science laboratory; substantially greater use needs to be made of out-of-school sites for the teaching of science. Such usage should result in a school science education that is more valid and more motivating and is better at fulfilling defensible aims of school science education. Our contention is that laboratory-based school science teaching needs to be complemented by out-of-school science learning that draws on the actual world (e.g. through fieldtrips), the presented world (e.g. in science centres, botanic gardens, zoos and science museums) and the virtual worlds that are increasingly available through information and communications technologies (ICT)

    Spectral, Compositional, and Physical Properties of the Upper Murray Formation and Vera Rubin Ridge, Gale Crater, Mars

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    During 2018 and 2019, the Mars Science Laboratory Curiosity rover investigated the chemistry, morphology, and stratigraphy of Vera Rubin ridge (VRR). Using orbital data from the Compact Reconnaissance Imaging Spectrometer for Mars, scientists attributed the strong 860 nm signal associated with VRR to the presence of red crystalline hematite. However, Mastcam multispectral data and CheMin X‐ray diffraction (XRD) measurements show that the depth of the 860 nm absorption is negatively correlated with the abundance of red crystalline hematite, suggesting that other mineralogical or physical parameters are also controlling the 860 nm absorption. Here, we examine Mastcam and ChemCam passive reflectance spectra from VRR and other locations to link the depth, position, and presence or absence of iron‐related mineralogic absorption features to the XRD‐derived rock mineralogy. Correlating CheMin mineralogy to spectral parameters showed that the ~860 nm absorption has a strong positive correlation with the abundance of ferric phyllosilicates. New laboratory reflectance measurements of powdered mineral mixtures can reproduce trends found in Gale crater. We hypothesize that variations in the 860 nm absorption feature in Mastcam and ChemCam observations of VRR materials are a result of three factors: (1) variations in ferric phyllosilicate abundance due to its ~800–1,000 nm absorption; (2) variations in clinopyroxene abundance because of its band maximum at ~860 nm; and (3) the presence of red crystalline hematite because of its absorption centered at 860 nm. We also show that relatively small changes in Ca‐sulfate abundance is one potential cause of the erosional resistance and geomorphic expression of VRR

    Bioanalytical method development and validation for determination of metoprolol tartarate and hydrochlorothiazide using HPTLC in human plasma

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    A simple, sensitive, rapid and economic chromatographic method has been developed for determination of metoprolol tartarate and hydrochlorothiazide in human plasma using paracetamol as an internal standard. The analytical technique used for method development was high-performance thin-layer chromatography. HPTLC Camag with precoated silica gel Plate 60F254 (20 cm×10 cm) at 250 µm thicknesses (E. Merck, Darmstadt, Germany) was used as the stationary phase. The mobile phase used consisted of chloroform: methanol: ammonia (9:1:0.5v/v/v). Densitometric analysis was carried out at a wavelength of 239 nm. The rf values for hydrochlorothiazide, paracetamol and metoprolol tartarate were 0.13±0.04, 0.28±0.05, 0.48±0.04, respectively. Plasma samples were extracted by protein precipitation with methanol. Concentration ranges of 200, 400, 600, 800, 1000, 1200 ng/mL and 2000, 4000, 6000, 8000, 10000, 12000 ng/mL of hydrochlorothiazide and metoprolol tartarate, respectively, were used with plasma for the calibration curves. The percent recovery of metoprolol tartarate and hydrochlorothiazide was found to be 77.30 and 77.02 %, respectively. The stability of metoprolol tartarate and hydrochlorothiazide in plasma were confirmed during three freeze-thaw cycles (-20 ºC) on a bench for 24 hours and post-preparatively for 48 hours. The proposed method was validated statistically and proved suitable for determination of metoprolol tartarate and hydrochlorothiazide in human plasma

    Genome resequencing reveals multiscale geographic structure and extensive linkage disequilibrium in the forest tree Populus trichocarpa

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    This is the publisher’s final pdf. The article is copyrighted by the New Phytologist Trust and published by John Wiley & Sons, Inc. It can be found at: http://onlinelibrary.wiley.com/journal/10.1111/%28ISSN%291469-8137. To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work.•Plant population genomics informs evolutionary biology, breeding, conservation and bioenergy feedstock development. For example, the detection of reliable phenotype–genotype associations and molecular signatures of selection requires a detailed knowledge about genome-wide patterns of allele frequency variation, linkage disequilibrium and recombination.\ud •We resequenced 16 genomes of the model tree Populus trichocarpa and genotyped 120 trees from 10 subpopulations using 29 213 single-nucleotide polymorphisms.\ud •Significant geographic differentiation was present at multiple spatial scales, and range-wide latitudinal allele frequency gradients were strikingly common across the genome. The decay of linkage disequilibrium with physical distance was slower than expected from previous studies in Populus, with r² dropping below 0.2 within 3–6 kb. Consistent with this, estimates of recent effective population size from linkage disequilibrium (N[subscript e] ≈ 4000–6000) were remarkably low relative to the large census sizes of P. trichocarpa stands. Fine-scale rates of recombination varied widely across the genome, but were largely predictable on the basis of DNA sequence and methylation features.\ud •Our results suggest that genetic drift has played a significant role in the recent evolutionary history of P. trichocarpa. Most importantly, the extensive linkage disequilibrium detected suggests that genome-wide association studies and genomic selection in undomesticated populations may be more feasible in Populus than previously assumed
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