732 research outputs found

    Kiwi forego vison in the guidance of their nocturnal activities

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    We propose that the Kiwi visual system has undergone adaptive regression evolution driven by the trade-off between the relatively low rate of gain of visual information that is possible at low light levels, and the metabolic costs of extracting that information

    Stable isotope values in modern bryozoan carbonate from New Zealand and implications for paleoenvironmental interpretation

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    Bryozoan carbonate contains useful geochemical evidence of temperate shelf paleoenvironments. Stable isotope values were determined for 103 modern marine bryozoan skeletons representing 30 species from New Zealand. δ18O values range from -1.4 to 2.8 VPDB, while δ13C range from -4.5 to 2.8 VPDB (values uncorrected for mineralogical variation). These values are distinct from those of both tropical marine skeletons and New Zealand Tertiary fossils. Most bryozoans secrete carbonate in or near isotopic equilibrium with sea water, except for Celleporina and Steginoporella. The complex and variable mineralogies of the bryozoans reported here make correction for mineralogical effects problematic. Nevertheless, mainly aragonitic forms display higher isotope values, as anticipated. Both temperature and salinity constrain δ18O and δ13C values, and vary with latitude and water depth. Ten samples from a single branch of Cinctipora elegans from the Otago shelf cover a narrow range, although the striking difference in carbon isotope values between the endozone and exozone probably reflects different mineralisation histories. Our stable isotope results from three different laboratories on a single population from a single location are encouragingly consistent. Monomineralic bryozoans, when carefully chosen to avoid species suspected of vital fractionation, have considerable potential as geochemical paleoenvironmental indicators, particularly in temperate marine environments where bryozoans are dominant sediment producers

    Prehospital critical care is associated with increased survival in adult trauma patients in Scotland

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    Background Scotland has three prehospital critical care teams (PHCCTs) providing enhanced care support to a usually paramedic-delivered ambulance service. The effect of the PHCCTs on patient survival following trauma in Scotland is not currently known nationally. Methods National registry-based retrospective cohort study using 2011-2016 data from the Scottish Trauma Audit Group. 30-day mortality was compared between groups after multivariate analysis to account for confounding variables. Results Our data set comprised 17 157 patients, with a mean age of 54.7 years and 8206 (57.5%) of male gender. 2877 patients in the registry were excluded due to incomplete data on their level of prehospital care, leaving an eligible group of 14 280. 13 504 injured adults who received care from ambulance clinicians (paramedics or technicians) were compared with 776 whose care included input from a PHCCT. The median Injury Severity Score (ISS) across all eligible patients was 9; 3076 patients (21.5%) met the ISS>15 criterion for major trauma. Patients in the PHCCT cohort were statistically significantly (all p < 0.01) more likely to be male; be transported to a prospective Major Trauma Centre; have suffered major trauma; have suffered a severe head injury; be transported by air and be intubated prior to arrival in hospital. Following multivariate analysis, the OR for 30-day mortality for patients seen by a PHCCT was 0.56 (95% CI 0.36 to 0.86, p=0.01). Conclusion Prehospital care provided by a physician-led critical care team was associated with an increased chance of survival at 30 days when compared with care provided by ambulance clinicians

    Higher Structures in M-Theory

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    The key open problem of string theory remains its non-perturbative completion to M-theory. A decisive hint to its inner workings comes from numerous appearances of higher structures in the limits of M-theory that are already understood, such as higher degree flux fields and their dualities, or the higher algebraic structures governing closed string field theory. These are all controlled by the higher homotopy theory of derived categories, generalised cohomology theories, and LL_\infty-algebras. This is the introductory chapter to the proceedings of the LMS/EPSRC Durham Symposium on Higher Structures in M-Theory. We first review higher structures as well as their motivation in string theory and beyond. Then we list the contributions in this volume, putting them into context.Comment: 22 pages, Introductory Article to Proceedings of LMS/EPSRC Durham Symposium Higher Structures in M-Theory, August 2018, references update

    Expressing ‘The Structure of’ in Homotopy Type Theory

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    As a new foundational language for mathematics with its very different idea as to the status of logic, we should expect homotopy type theory to shed new light on some of the problems of philosophy which have been treated by logic. In this article, definite description, and in particular its employment within mathematics, is formulated within the type theory. Homotopy type theory has been proposed as an inherently structuralist foundational language for mathematics. Using the new formulation of definite descriptions, opportunities to express ‘the structure of’ within homotopy type theory are explored, and it is shown there is little or no need for this expression

    A transcriptome-driven analysis of epithelial brushings and bronchial biopsies to define asthma phenotypes in U-BIOPRED

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    RATIONALE AND OBJECTIVES: Asthma is a heterogeneous disease driven by diverse immunologic and inflammatory mechanisms. We used transcriptomic profiling of airway tissues to help define asthma phenotypes. METHODS: The transcriptome from bronchial biopsies and epithelial brushings of 107 moderate-to-severe asthmatics were annotated by gene-set variation analysis (GSVA) using 42 gene-signatures relevant to asthma, inflammation and immune function. Topological data analysis (TDA) of clinical and histological data was used to derive clusters and the nearest shrunken centroid algorithm used for signature refinement. RESULTS: 9 GSVA signatures expressed in bronchial biopsies and airway epithelial brushings distinguished two distinct asthma subtypes associated with high expression of T-helper type 2 (Th-2) cytokines and lack of corticosteroid response (Group 1 and Group 3). Group 1 had the highest submucosal eosinophils, high exhaled nitric oxide (FeNO) levels, exacerbation rates and oral corticosteroid (OCS) use whilst Group 3 patients showed the highest levels of sputum eosinophils and had a high BMI. In contrast, Group 2 and Group 4 patients had an 86% and 64% probability of having non-eosinophilic inflammation. Using machine-learning tools, we describe an inference scheme using the currently-available inflammatory biomarkers sputum eosinophilia and exhaled nitric oxide levels along with OCS use that could predict the subtypes of gene expression within bronchial biopsies and epithelial cells with good sensitivity and specificity. CONCLUSION: This analysis demonstrates the usefulness of a transcriptomic-driven approach to phenotyping that segments patients who may benefit the most from specific agents that target Th2-mediated inflammation and/or corticosteroid insensitivity

    Portación de Staphylococcus aureus en manipuladores de alimentos de la ciudad de Gualeguaychú

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    Food handlers in the community who do not have good personal hygiene can be vehicles for transmission of Staphylococcus aureus (SAU). Their strains have become increasingly resistant to beta-lactam antibiotics, which is a problem for food safety. Isolation was performed on samples of hands and nostrils of 49 ice cream dispensers and 43 food handlers. Methicillin resistance was determined in the positive samples using the cefoxitin disk diffusion technique (30 μg) and 24 positive SAU samples were also subjected to enterotoxin detection using VIDAS Staph enterotoxy reagents. Hygienic habits were evaluated, applying a questionnaire. Of the ice cream sellers, 19 were carriers (39%); for the handlers at educational institutions this percentage was 47% (n = 20). Habits and knowledge found have flaws. For the first sampling (n = 30), a resistance in nostrils of 13% (n = 4) and for hands of 7% was obtained, and in the second (n = 20), of 20% (n = 4) and of 5% (n = 1) respectively and for educational institutions (n ​​= 43), of 25% (n = 11) for nostrils and of 19% (n = 8) for hands. They were enterotoxigenic (33%) of the strains. The results showed the presence of MRSA among these handlers and the risk of being disseminators. Courses should focus on preventive measures of contamination of food and talk about the importance of this issue working interdisciplinary with professionals in the field and with those responsible for public health.Los elaboradores que preparan alimentos y no mantienen una buena higiene personal pueden ser vehículos de transmisión de Staphylococcus aureus (SAU); microorganismo causante de intoxicaciones alimentarias que últimamente se ha tornado más resistente a antibióticos betalactámicos, representando un problema en salud pública. Se lo aisló e identificó en muestras de manos y narinas de 49 expendedores de helados y 43 elaboradores de alimentos en instituciones educativas, se empleó la técnica de difusión con disco de cefoxitina (30 µg) propuesta por CLSI (Clinical &amp; Laboratory Standards Institute) para determinar su resistencia a meticilina. Se evaluaron los hábitos higiénicos aplicando un cuestionario de autoinforme y a 24 cepas extraidas de 24 muestras seleccionadas al azar que fueron SAU positivas, se les realizó la detección de enterotoxinas utilizando reactivos VIDAS Staph enterotoxin. Se obtuvo que un 39% de los expendedores y un 47% de los elaboradores resultaron portadores. El primer muestreo (n=30), marcó una resistencia en narinas del 13% y manos de 7%, en los muestreos siguientes se observó un incremento de SARM (Staphylococcus aureus resistente a meticilina). Respecto a la detección de toxinas de las 24 cepas investigadas, 8 resultaron enterotoxigénicas (33%). Los hábitos y conocimientos evaluados marcaron falencias en puntos críticos, los resultados mostraron la presencia de SARM entre los manipuladores con riesgo de ser diseminadores de dichas cepas. Se deberían programar cursos haciendo énfasis en medidas preventivas que eviten la contaminación alimentaria, realizando un plan de concientización a la población y utilizando estos datos como punto de partida. Es necesario trabajar en forma interdisciplinaria con profesionales afines y responsables de salud pública

    From Euclidean Geometry to Knots and Nets

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    This document is the Accepted Manuscript of an article accepted for publication in Synthese. Under embargo until 19 September 2018. The final publication is available at Springer via https://doi.org/10.1007/s11229-017-1558-x.This paper assumes the success of arguments against the view that informal mathematical proofs secure rational conviction in virtue of their relations with corresponding formal derivations. This assumption entails a need for an alternative account of the logic of informal mathematical proofs. Following examination of case studies by Manders, De Toffoli and Giardino, Leitgeb, Feferman and others, this paper proposes a framework for analysing those informal proofs that appeal to the perception or modification of diagrams or to the inspection or imaginative manipulation of mental models of mathematical phenomena. Proofs relying on diagrams can be rigorous if (a) it is easy to draw a diagram that shares or otherwise indicates the structure of the mathematical object, (b) the information thus displayed is not metrical and (c) it is possible to put the inferences into systematic mathematical relation with other mathematical inferential practices. Proofs that appeal to mental models can be rigorous if the mental models can be externalised as diagrammatic practice that satisfies these three conditions.Peer reviewe

    Mathematical practice, crowdsourcing, and social machines

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    The highest level of mathematics has traditionally been seen as a solitary endeavour, to produce a proof for review and acceptance by research peers. Mathematics is now at a remarkable inflexion point, with new technology radically extending the power and limits of individuals. Crowdsourcing pulls together diverse experts to solve problems; symbolic computation tackles huge routine calculations; and computers check proofs too long and complicated for humans to comprehend. Mathematical practice is an emerging interdisciplinary field which draws on philosophy and social science to understand how mathematics is produced. Online mathematical activity provides a novel and rich source of data for empirical investigation of mathematical practice - for example the community question answering system {\it mathoverflow} contains around 40,000 mathematical conversations, and {\it polymath} collaborations provide transcripts of the process of discovering proofs. Our preliminary investigations have demonstrated the importance of "soft" aspects such as analogy and creativity, alongside deduction and proof, in the production of mathematics, and have given us new ways to think about the roles of people and machines in creating new mathematical knowledge. We discuss further investigation of these resources and what it might reveal. Crowdsourced mathematical activity is an example of a "social machine", a new paradigm, identified by Berners-Lee, for viewing a combination of people and computers as a single problem-solving entity, and the subject of major international research endeavours. We outline a future research agenda for mathematics social machines, a combination of people, computers, and mathematical archives to create and apply mathematics, with the potential to change the way people do mathematics, and to transform the reach, pace, and impact of mathematics research.Comment: To appear, Springer LNCS, Proceedings of Conferences on Intelligent Computer Mathematics, CICM 2013, July 2013 Bath, U
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