3,446 research outputs found

    A Geo Information System (GIS) for circum-arctic coastal dynamics

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    Coastal erosion forms a major source of the sediment, organic carbon and nutrient flux into the arctic basin. Recent studies indicate that sediment input resulting from the erosion of ice-rich, permafrost-dominated coasts might be equal to or greater than river input. The program Arctic Coastal Dynamics (ACD) has been developed to improve our understanding of circum-arctic coastal dynamics as a function of environmental forcing, coastal geology, geocryology and morphodynamic behavior. Under this framework a circum-arctic Geo Information System (GIS) has been developed, which is applied to display generalized information on coastal characteristics and to analyse coastal material fluxes. The coastal GIS is based on a digital elevation model, which was constructed from the International Bathymetric Chart of the Arctic Ocean, and permafrost parameters adopted from the Circumpolar Active-Layer Permafrost System. A segmentation of the Laptev Sea coastline was performed as a first step towards a GIS-based quantification of the sediment and total organic carbon (TOC) fluxes resulting from coastal erosion

    Characterizing Van Kampen Squares via Descent Data

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    Categories in which cocones satisfy certain exactness conditions w.r.t. pullbacks are subject to current research activities in theoretical computer science. Usually, exactness is expressed in terms of properties of the pullback functor associated with the cocone. Even in the case of non-exactness, researchers in model semantics and rewriting theory inquire an elementary characterization of the image of this functor. In this paper we will investigate this question in the special case where the cocone is a cospan, i.e. part of a Van Kampen square. The use of Descent Data as the dominant categorical tool yields two main results: A simple condition which characterizes the reachable part of the above mentioned functor in terms of liftings of involved equivalence relations and (as a consequence) a necessary and sufficient condition for a pushout to be a Van Kampen square formulated in a purely algebraic manner.Comment: In Proceedings ACCAT 2012, arXiv:1208.430

    The Drosophila genome nexus: a population genomic resource of 623 Drosophila melanogaster genomes, including 197 from a single ancestral range population.

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    Hundreds of wild-derived Drosophila melanogaster genomes have been published, but rigorous comparisons across data sets are precluded by differences in alignment methodology. The most common approach to reference-based genome assembly is a single round of alignment followed by quality filtering and variant detection. We evaluated variations and extensions of this approach and settled on an assembly strategy that utilizes two alignment programs and incorporates both substitutions and short indels to construct an updated reference for a second round of mapping prior to final variant detection. Utilizing this approach, we reassembled published D. melanogaster population genomic data sets and added unpublished genomes from several sub-Saharan populations. Most notably, we present aligned data from phase 3 of the Drosophila Population Genomics Project (DPGP3), which provides 197 genomes from a single ancestral range population of D. melanogaster (from Zambia). The large sample size, high genetic diversity, and potentially simpler demographic history of the DPGP3 sample will make this a highly valuable resource for fundamental population genetic research. The complete set of assemblies described here, termed the Drosophila Genome Nexus, presently comprises 623 consistently aligned genomes and is publicly available in multiple formats with supporting documentation and bioinformatic tools. This resource will greatly facilitate population genomic analysis in this model species by reducing the methodological differences between data sets

    Precautionary labelling of foods for allergen content: are we ready for a global framework?

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    © 2014 Allen et al.; licensee BioMed Central Ltd.Food allergy appears to be on the rise with the current mainstay of treatment centred on allergen avoidance. Mandatory allergen labelling has improved the safety of food for allergic consumers. However an additional form of voluntary labelling (termed precautionary allergen labelling) has evolved on a wide range of packaged goods, in a bid by manufacturers to minimise risk to customers, and the negative impact on business that might result from exposure to trace amounts of food allergen present during cross-contamination during production. This has resulted in near ubiquitous utilisation of a multitude of different precautionary allergen labels with subsequent confusion amongst many consumers as to their significance. The global nature of food production and manufacturing makes harmonisation of allergen labelling regulations across the world a matter of increasing importance. Addressing inconsistencies across countries with regards to labelling legislation, as well as improvement or even banning of precautionary allergy labelling are both likely to be significant steps forward in improved food safety for allergic families. This article outlines the current status of allergen labelling legislation around the world and reviews the value of current existing precautionary allergen labelling for the allergic consumer. We strongly urge for an international framework to be considered to help roadmap a solution to the weaknesses of the current systems, and discuss the role of legislation in facilitating this

    Faecal carriage of multi-drug resistant Enterobacteriaceae in hospitalized children at University Teaching Hospital Sylvanus Olympio of Lomé, Togo

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    Background: High prevalence of infections and associated antibiotherapy may put children at increased risk for development of multidrug-resistance (MDR), mostly to bacterial infections. The objective of this study therefore was to determine the prevalence of gastrointestinal carriage of MDR Enterobacteriaceae among hospitalized children in the Paediatric department of Sylvanus Olympio University Hospital, Lomé, Togo.Methodology: A descriptive cross-sectional study was carried out on randomly selected hospitalized children in the Paediatric wards of the hospital from November 03 to November 10, 2020, after obtaining informed consent from their parents/guardians. Rectal swabs and stool samples were collected from each participant and cultured for isolation of members of the family Enterobacteriaceae on Hektoen enteric agar containing 4 µg/L cefotaxime, which was incubated aerobically at 37oC for 24 hours. The isolates were identified using in-house biochemical tests. Antibiotic susceptibility test (AST) of each isolate to a panel of antibiotics including ertapenem and imipenem was done by the disc diffusion method and interpreted according to the European Committee on Antimicrobial Susceptibility Testing (EUCAST) clinical breakpoints version 2020 V.1.1. ESBL production was detected by the double-disc synergy test of amoxicillin and clavulanic acid, and resistance to carbapenem was inferred by resistance to ertapenem and imipenem discs in the AST. Multi-drug resistance (MDR) was defined as resistance to at least three families of antibiotics. Statistical analysis of data was carried out on Excel 2010 and EPI INFO 7.2 and p value < 0.05 was considered to be statistical significance. Results: A total of 70 hospitalized children during the study period were randomly recruited with an average age of 4 years 3 days and a range of 1 day to 18 years. The male gender was predominant (54.3%) with a M: F ratio of 1.2. Samples were culture positive in 85.7% (60/70) and a total of 72 species of Enterobacteriaceae were isolated in 93.3% (56/60) of these cultures. Escherichia coli was the most frequently isolated species(56.9%, 41/72). More than 90% (65/72) of the isolates were resistant to ampicillin, 58.3% (42/72) to third generation cephalosporins, 59.7% (43/72) to fourth generation cephalosporins, 43% (31/72) to aminoglycosides, 55.6% (40/72) were multi-drug resistant, 48.6% (35/72) were ESBL-producing strains, and 6.9% (5/72) were carbapenem resistant. Eighty-three percent (29/35) of ESBL-producing and all the carbapenem resistant isolates (5/5) were recovered from children on antibiotic therapy. The prevalence of ESBL-producing phenotypes among culture-positive children on antibiotic treatment (72.5%, 29/40) was significantly higher than among culture-positive children not on antibiotic treatment (20.0%, 4/20), indicating that antibiotic therapy was significantly associated with carriage of MDR isolates (OR=10.545, 95% CI=2.882-38.590, p=0.0002). Conclusion: The high faecal carriage rate of MDR Enterobacteriaceae, which are all ESBL-producing strains, in this study is worrying. There is urgent need to develop measures to monitor and limit the spread of these MDR organisms in children and the community in Togo

    Risk factors for patellofemoral pain: a systematic review and meta-analysis.

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    “This article has been accepted for publication in British Journal of Sports Medicine 2019 following peer review, and the Version of Record can be accessed online at http://dx.doi.org/10.1136/bjsports-2017-098890.”BACKGROUND: Patellofemoral pain (PFP) is a prevalent condition commencing at various points throughout life. We aimed to provide an evidence synthesis concerning predictive variables for PFP, to aid development of preventative interventions. METHODS: We searched Medline, Web of Science and SCOPUS until February 2017 for prospective studies investigating at least one potential risk factor for future PFP. Two independent reviewers appraised methodological quality using the Newcastle-Ottawa Scale. We conducted meta-analysis where appropriate, with standardised mean differences (SMD) and risk ratios calculated for continuous and nominal scaled data. RESULTS: This review included 18 studies involving 4818 participants, of whom 483 developed PFP (heterogeneous incidence 10%). Three distinct subgroups (military recruits, adolescents and recreational runners) were identified. Strong to moderate evidence indicated that age, height, weight, body mass index (BMI), body fat and Q angle were not risk factors for future PFP. Moderate evidence indicated that quadriceps weakness was a risk factor for future PFP in the military, especially when normalised by BMI (SMD -0.69, CI -1.02, -0.35). Moderate evidence indicated that hip weakness was not a risk factor for future PFP (multiple pooled SMDs, range -0.09 to -0.20), but in adolescents, moderate evidence indicated that increased hip abduction strength was a risk factor for future PFP (SMD 0.71, CI 0.39, 1.04). CONCLUSIONS: This review identified multiple variables that did not predict future PFP, but quadriceps weakness in military recruits and higher hip strength in adolescents were risk factors for PFP. Identifying modifiable risk factors is an urgent priority to improve prevention and treatment outcomes

    Determining the origin of synchronous multifocal bladder cancer by exome sequencing

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    Background: Synchronous multifocal tumours are commonly observed in urothelial carcinomas of the bladder. The origin of these physically independent tumours has been proposed to occur by either intraluminal migration (clonal) or spontaneous transformation of multiple cells by carcinogens (field effect). It is unclear which model is correct, with several studies supporting both hypotheses. A potential cause of this uncertainty may be the small number of genetic mutations previously used to quantify the relationship between these tumours. Methods: To better understand the genetic lineage of these tumours we conducted exome sequencing of synchronous multifocal pTa urothelial bladder cancers at a high depth, using multiple samples from three patients. Results: Phylogenetic analysis of high confidence single nucleotide variants (SNV) demonstrated that the sequenced multifocal bladder cancers arose from a clonal origin in all three patients (bootstrap value 100 %). Interestingly, in two patients the most common type of tumour-associated SNVs were cytosine mutations of TpC*dinucleotides (Fisher's exact test p < 10-41), likely caused by APOBEC-mediated deamination. Incorporating these results into our clonal model, we found that TpC*type mutations occurred 2-5× more often among SNVs on the ancestral branches than in the more recent private branches (p < 10-4) suggesting that TpC*mutations largely occurred early in the development of the tumour. Conclusions: These results demonstrate that synchronous multifocal bladder cancers frequently arise from a clonal origin. Our data also suggests that APOBEC-mediated mutations occur early in the development of the tumour and may be a driver of tumourigenesis in non-muscle invasive urothelial bladder cancer. © 2015 Acar et al

    Three qubit entanglement within graphical Z/X-calculus

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    The compositional techniques of categorical quantum mechanics are applied to analyse 3-qubit quantum entanglement. In particular the graphical calculus of complementary observables and corresponding phases due to Duncan and one of the authors is used to construct representative members of the two genuinely tripartite SLOCC classes of 3-qubit entangled states, GHZ and W. This nicely illustrates the respectively pairwise and global tripartite entanglement found in the W- and GHZ-class states. A new concept of supplementarity allows us to characterise inhabitants of the W class within the abstract diagrammatic calculus; these method extends to more general multipartite qubit states.Comment: In Proceedings HPC 2010, arXiv:1103.226

    Arctic shipping emissions inventories and future scenarios

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    This paper presents 5 km×5 km Arctic emissions inventories of important greenhouse gases, black carbon and other pollutants under existing and future (2050) scenarios that account for growth of shipping in the region, potential diversion traffic through emerging routes, and possible emissions control measures. These high-resolution, geospatial emissions inventories for shipping can be used to evaluate Arctic climate sensitivity to black carbon (a short-lived climate forcing pollutant especially effective in accelerating the melting of ice and snow), aerosols, and gaseous emissions including carbon dioxide. We quantify ship emissions scenarios which are expected to increase as declining sea ice coverage due to climate change allows for increased shipping activity in the Arctic. A first-order calculation of global warming potential due to 2030 emissions in the high-growth scenario suggests that short-lived forcing of ~4.5 gigagrams of black carbon from Arctic shipping may increase global warming potential due to Arctic ships' CO<sub>2</sub> emissions (~42 000 gigagrams) by some 17% to 78%. The paper also presents maximum feasible reduction scenarios for black carbon in particular. These emissions reduction scenarios will enable scientists and policymakers to evaluate the efficacy and benefits of technological controls for black carbon, and other pollutants from ships

    Rewriting modulo symmetric monoidal structure

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    String diagrams are a powerful and intuitive graphical syntax for terms of symmetric monoidal categories (SMCs). They find many applications in computer science and are becoming increasingly relevant in other fields such as physics and control theory.An important role in many such approaches is played by equational theories of diagrams, typically oriented and applied as rewrite rules. This paper lays a comprehensive foundation for this form of rewriting. We interpret diagrams combinatorially as typed hypergraphs and establish the precise correspondence between diagram rewriting modulo the laws of SMCs on the one hand and double pushout (DPO) rewriting of hypergraphs, subject to a soundness condition called convexity, on the other. This result rests on a more general characterisation theorem in which we show that typed hypergraph DPO rewriting amounts to diagram rewriting modulo the laws of SMCs with a chosen special Frobenius structure.We illustrate our approach with a proof of termination for the theory of non-commutative bimonoids
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