386 research outputs found

    Using deep learning to model elevation differences between 2 radar and laser altimetry

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    peer reviewedSatellite and airborne observations of surface elevation are critical in understanding climatic and glaciological processes and quantifying their impact on changes in ice masses and sea level contribution. With the growing number of dedicated airborne campaigns and experimental and operational satellite missions, the science community has access to unprecedented and ever-increasing data. Combining elevation datasets allows potentially greater spatial-temporal coverage and improved accuracy; however, combining data from different sensor types and acquisition modes is difficult by differences in intrinsic sensor properties and processing methods. This study focuses on the combination of elevation measurements derived from ICESat-2 and Operation IceBridge LIDAR instruments and from CryoSat-2’s novel interferometric radar altimeter over Greenland. We develop a deep neural network based on sub-waveform information from CryoSat-2, elevation differences between radar and LIDAR, and additional inputs representing local geophysical information. A time series of maps are created showing observed LIDAR-radar differences and neural network model predictions. Mean LIDAR vs. interferometric radar adjustments and the broad spatial and temporal trends thereof are recreated by the neural network. The neural network also predicts radar-LIDAR differences with respect to waveform parameters better than a simple linear model; however, point level adjustments and the magnitudes of the spatial and temporal trends are underestimated

    Highly ordered N-heterocyclic carbene monolayers on Cu(111)

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    EA and FG acknowledge funding from EPSRC grants (EA: EP/R512199/1; FG: EP/S027270/1). We thank the EaStCHEM for computational support via the EaStCHEM Research Computing facility. CMC thanks the Natural Sciences and Engineering Research Council of Canada (NSERC) and the Canada Foundation for Innovation (CFI) for funding of the work from her lab described in this article. AJV acknowledges NSERC for a Vanier scholarship and the Walter C. Sumner foundation for additional financial support. IS acknowledges Queen’s University for the RT Mohan Scholarship and the Ontario government for an Ontario Graduate Scholarship.The benzannulated N-heterocyclic carbene, 1,3-dibenzylbenzimidazolylidene (NHCDBZ) forms large, highly ordered domains when adsorbed on Cu(111) under ultrahigh vacuum conditions. A combination of scanning tunnelling microscopy (STM), high resolution electron energy loss spectroscopy (HREELS) and density functional theory (DFT) calculations reveals that the overlayer consists of vertical benzannulated NHC moieties coordinating to Cu adatoms. Long range order results from the placement of the two benzyl substituents on opposite sides of the benzimidazole moiety, with their aromatic rings approximately parallel to the surface. The organization of three surface-bound benzyl substituents from three different NHCs into a triangular array controls the formation of a highly ordered Kagome-like surface lattice. By comparison with earlier studies of NHCs on Cu(111), we show that the binding geometry and self-assembly of NHCDBZ are influenced by intermolecular and adsorbate-substrate interactions and facilitated by the flexibility of the methylene linkage between the N-heterocycle and the aromatic wingtip substituents.Publisher PDFPeer reviewe

    N-heterocyclic carbenes reduce and functionalize copper oxide surfaces in one pot

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    The Natural Sciences and Engineering Research Council of Canada (NSERC) and the Canada Foundation for Innovation (CFI) are thanked for financial support of this work in terms of operating and equipment grants to CMC and JHH. AJV and MRN thank the Ontario government for OGS fellowships. AJV thanks NSERC for a Vanier Scholarship and also the Walter C. Sumner foundation for additional scholarship support.Benzimidazolium hydrogen carbonate salts have been shown to act as N-heterocyclic carbene precursors which can remove oxide from copper oxide surfaces and functionalize the resulting metallic surfaces in a single step. Both the surfaces and the etching products are fully characterized by spectroscopic methods. Analysis of surfaces before and after NHC treatment by X-ray photoelectron spectroscopy demonstrates the complete removal of copper(II) oxide. Using 13C-labelling, we determine that the products of this transformation include a cyclic urea, a ring-opened formamide and a bis-carbene copper(I) complex. These results illustrate the potential of NHCs to functionalize a much broader class of metals, including those prone to oxide treatment, greatly facilitating the preparation of NHC-based films on metals other than gold.PostprintPeer reviewe

    Increasing Short-Stay Unplanned Hospital Admissions among Children in England; Time Trends Analysis '97-'06

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    BACKGROUND: Timely care by general practitioners in the community keeps children out of hospital and provides better continuity of care. Yet in the UK, access to primary care has diminished since 2004 when changes in general practitioners' contracts enabled them to 'opt out' of providing out-of-hours care and since then unplanned pediatric hospital admission rates have escalated, particularly through emergency departments. We hypothesised that any increase in isolated short stay admissions for childhood illness might reflect failure to manage these cases in the community over a 10 year period spanning these changes. METHODS AND FINDINGS: We conducted a population based time trends study of major causes of hospital admission in children 2 days. By 2006, 67.3% of all unplanned admissions were isolated short stays <2 days. The increases in admission rates were greater for common non-infectious than infectious causes of admissions. CONCLUSIONS: Short stay unplanned hospital admission rates in young children in England have increased substantially in recent years and are not accounted for by reductions in length of in-hospital stay. The majority are isolated short stay admissions for minor illness episodes that could be better managed by primary care in the community and may be evidence of a failure of primary care services

    (Dis)connected communities and sustainable place-making

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    Why, despite a recent surge in the UK in “sustainable communities” policy discourse, do so many community-led sustainability initiatives remain fragmented, marginal and disconnected from local government strategies? How can community- and government-led sustainability initiatives be better integrated such that they add significantly to a denser matrix and cluster of sustainable places? These questions, we argue, lie at the heart of current sustainable place-making debates. With particular reference to two spatial scales of analysis and action, the small town of Stroud, England and the city of Cardiff, Wales, we explore the twin processes of disconnection and connection between community sustainability activists and local state actors. We conclude that whilst there will always remain a need for community groups to protect the freedom which comes from acting independently, for community activists and policy-makers alike, there are nevertheless a series of mutual benefits to be had from co-production. However, in setting out these benefits we also emphasise the dual need for local government to play a much more nuanced, integrative and facilitatory role, in addition to, but separate from, its more traditional regulatory role

    On the Irrelevance of Neuromyths to Teacher Effectiveness: Comparing Neuro-Literacy Levels Amongst Award-Winning and Non-award Winning Teachers

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    A number of studies have recently demonstrated a high level of belief in ‘neuromyths’ (fallacious arguments about the brain) amongst trainee and non-award winning educators. The authors of these studies infer this to mean that acceptance of these neuromyths has a negative impact on teaching effectiveness. In this study, we explored this assumption by assessing the prevalence of neuromyth acceptance amongst a group of internationally recognized, award-winning teachers and comparing this to previously published data with trainee and non-award winning teacher populations. Results revealed the acceptance of neuromyths to be nearly identical between these two groups, with the only difference occurring on 2 (out of 15) items. These findings suggest that one cannot make simple, unqualified arguments concerning the relationship between belief in neuromyths and teacher effectiveness. In fact, the idea that neuromyths negatively impact upon teaching might, itself, be a neuromyth

    Evaluating a complex research capacity-building intervention: reflections on an evaluation of the African Institutions Initiative

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    Increasing policy demand for realist evaluations of research and capacity-building programmes reflects a recognition of the management, governance and impact gains that can result from evaluation. However, the evidence base on how to successfully implement realist evaluations of complex interventions in international development efforts is scarce. We know little about the associated merits, limitations and ways to mitigate challenges. There is a need for reflective work which considers the methodology in context. This paper shares learning from the experience of conducting a realist, theory-of-change driven evaluation of the African Institutions Initiative, a Wellcome Trust funded programme which aimed to build sustainable health research capacity in Africa at institutional and network levels, across seven research consortia. We reflect on the key challenges experienced throughout the evaluation and recommend ways of managing them, highlight opportunities and critical success factors associated with this evaluation approach, as well as elaborate on alternative evaluation approaches

    Genomic-Bioinformatic Analysis of Transcripts Enriched in the Third-Stage Larva of the Parasitic Nematode Ascaris suum

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    Differential transcription in Ascaris suum was investigated using a genomic-bioinformatic approach. A cDNA archive enriched for molecules in the infective third-stage larva (L3) of A. suum was constructed by suppressive-subtractive hybridization (SSH), and a subset of cDNAs from 3075 clones subjected to microarray analysis using cDNA probes derived from RNA from different developmental stages of A. suum. The cDNAs (n = 498) shown by microarray analysis to be enriched in the L3 were sequenced and subjected to bioinformatic analyses using a semi-automated pipeline (ESTExplorer). Using gene ontology (GO), 235 of these molecules were assigned to ‘biological process’ (n = 68), ‘cellular component’ (n = 50), or ‘molecular function’ (n = 117). Of the 91 clusters assembled, 56 molecules (61.5%) had homologues/orthologues in the free-living nematodes Caenorhabditis elegans and C. briggsae and/or other organisms, whereas 35 (38.5%) had no significant similarity to any sequences available in current gene databases. Transcripts encoding protein kinases, protein phosphatases (and their precursors), and enolases were abundantly represented in the L3 of A. suum, as were molecules involved in cellular processes, such as ubiquitination and proteasome function, gene transcription, protein–protein interactions, and function. In silico analyses inferred the C. elegans orthologues/homologues (n = 50) to be involved in apoptosis and insulin signaling (2%), ATP synthesis (2%), carbon metabolism (6%), fatty acid biosynthesis (2%), gap junction (2%), glucose metabolism (6%), or porphyrin metabolism (2%), although 34 (68%) of them could not be mapped to a specific metabolic pathway. Small numbers of these 50 molecules were predicted to be secreted (10%), anchored (2%), and/or transmembrane (12%) proteins. Functionally, 17 (34%) of them were predicted to be associated with (non-wild-type) RNAi phenotypes in C. elegans, the majority being embryonic lethality (Emb) (13 types; 58.8%), larval arrest (Lva) (23.5%) and larval lethality (Lvl) (47%). A genetic interaction network was predicted for these 17 C. elegans orthologues, revealing highly significant interactions for nine molecules associated with embryonic and larval development (66.9%), information storage and processing (5.1%), cellular processing and signaling (15.2%), metabolism (6.1%), and unknown function (6.7%). The potential roles of these molecules in development are discussed in relation to the known roles of their homologues/orthologues in C. elegans and some other nematodes. The results of the present study provide a basis for future functional genomic studies to elucidate molecular aspects governing larval developmental processes in A. suum and/or the transition to parasitism

    Comparing bee species responses to chemical mixtures: common response patterns?

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    Pollinators in agricultural landscapes can be exposed to mixtures of pesticides and environmental pollutants. Existing mixture toxicity modelling approaches, such as the models of concentration addition and independent action and the mechanistic DEBtox framework have been previously shown as valuable tools for understanding and ultimately predicting joint toxicity. Here we apply these mixture models to investigate the potential to interpret the effects of semi-chronic binary mixture exposure for three bee species: Apis mellifera, Bombus terrestris and Osmia bicornis within potentiation and mixture toxicity experiments. In the potentiation studies, the effect of the insecticide dimethoate with added propiconazole fungicide and neonicotinoid insecticide clothianidin with added tau-fluvalinate pyrethroid acaricide showed no difference in toxicity compared to the single chemical alone. Clothianidin toxicity showed a small scale, but temporally conserved increase in exposure conducted in the presence of propiconazole, particularly for B. terrestris and O. bicornis, the latter showing a near three-fold increase in clothianidin toxicity in the presence of propiconazole. In the mixture toxicity studies, the dominant response patterns were of additivity, however, binary mixtures of clothianidin and dimethoate in A. mellifera, B. terrestris and male O. bicornis there was evidence of a predominant antagonistic interaction. Given the ubiquitous nature of exposures to multiple chemicals, there is an urgent need to consider mixture effects in pollinator risk assessments. Our analyses suggest that current models, particularly those that utilise time-series data, such as DEBtox, can be used to identify additivity as the dominant response pattern and also those examples of interactions, even when small-scale, that may need to be taken into account during risk assessment
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