21,024 research outputs found

    Successful difficult airway intubation using the Miller laryngoscope blade and paraglossal technique – a comparison with the Macintosh blade and midline technique

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    In anaesthetic practice clinicians are often faced with di cult airway situations. The conventional approach to intubation is the midline technique using a curved Macintosh blade for direct laryngoscopy. However, we have been successful in such a case using old technology and a seldom-used technique. This case raised the question whether older, alternative, methods of tracheal intubation may o er an advantage in airway management above the conventional practice. During pre-operative evaluation a patient presented with a large visible epiglottis on evaluation of the mouth and oropharynx. On direct laryngoscopy with a Macintosh 3 laryngoscope blade and the midline technique, a Cormack and Lehane grade-3b view was obtained due to the long epiglottis but normal position of the larynx. The Miller 4 blade and the paraglossal technique yielded a Cormack and Lehane grade-1 view and the trachea was successfully intubated using this approach. Use of the Miller blade and the paraglossal technique provided a perfect view of the glottis. Based on this experience and the findings of several studies on this topic, this approach could be a viable alternative to airway management.Keywords: difficult airway, Miller blade, Mallampati 0, Macintosh technique, paraglossal techniqu

    Towards an understanding of hole superconductivity

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    From the very beginning K. Alex M\"uller emphasized that the materials he and George Bednorz discovered in 1986 were holehole superconductors. Here I would like to share with him and others what I believe to be thethe key reason for why high TcT_c cuprates as well as all other superconductors are hole superconductors, which I only came to understand a few months ago. This paper is dedicated to Alex M\"uller on the occasion of his 90th birthday.Comment: Dedicated to Alex M\"uller on the Occasion of his 90th Birthday. arXiv admin note: text overlap with arXiv:1703.0977

    Association of chronic insomnia symptoms and recurrent extreme sleep duration over 10 years with well-being in older adults: a cohort study

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    OBJECTIVES: The extent to which aspects of sleep affect well-being in the long-term remains unclear. This longitudinal study examines the association between chronic insomnia symptoms, recurrent sleep duration and well-being at older ages. SETTING: A prospective cohort of UK civil servants (the Whitehall II study). PARTICIPANTS: 4491 women and men (25.2% women) with sleep measured 3 times over 10 years and well-being once at age 55-79 years. Insomnia symptoms and sleep duration were assessed through self-reports in 1997-1999, 2003-2004 and 2007-2009. PRIMARY OUTCOME MEASURES: Indicators of well-being, measured in 2007-2009, were the Control, Autonomy, Self-realisation and Pleasure measure (CASP-19) of overall well-being (range 0-57) and the physical and mental well-being component scores (range 0-100) of the Short Form Health Survey (SF-36). RESULTS: In maximally adjusted analyses, chronic insomnia symptoms were associated with poorer overall well-being (difference between insomnia at 3 assessments vs none -7.0 (SE=0.4) p9 h reported at 2 or 3 assessments vs none -3.5 (SE=0.9), p<0.001) were associated with poorer physical well-being. CONCLUSIONS: We conclude that in older people, chronic insomnia symptoms are negatively associated with all aspects of well-being, whereas recurrent long and short sleep is only associated with reduced physical well-being

    Linking inter-annual variation in environment, phenology, and abundance for a montane butterfly community (article)

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    This is the final version. Available from the Ecological Society of America via the DOI in this record. The dataset associated with this article is located in ORE at: https://doi.org/10.24378/exe.1963Climate change has caused widespread shifts in species’ phenology, but the consequences for population and community dynamics remain unclear because of uncertainty regarding the species-specific drivers of phenology and abundance, and the implications for synchrony among interacting species. Here, we develop a statistical model to quantify inter-annual variation in phenology and abundance over an environmental gradient, and use it to identify potential drivers of phenology and abundance in co-occurring species. We fit the model to counts of 10 butterfly species with single annual generations over a mountain elevation gradient, as an exemplar system in which temporally limited availability of biotic resources and favorable abiotic conditions impose narrow windows of seasonal activity. We estimate parameters describing changes in abundance, and the peak time and duration of the flight period, over ten years (2004–2013) and across twenty sample locations (930–2,050 m) in central Spain. We also use the model outputs to investigate relationships of phenology and abundance with temperature and rainfall. Annual shifts in phenology were remarkably consistent among species, typically showing earlier flight periods during years with warm conditions in March or May–June. In contrast, inter-annual variation in relative abundance was more variable among species, and generally less well associated with climatic conditions. Nevertheless, warmer temperatures in June were associated with increased relative population growth in three species, and five species had increased relative population growth in years with earlier flight periods. These results suggest that broadly coherent interspecific changes to phenology could help to maintain temporal synchrony in community dynamics under climate change, but that the relative composition of communities may vary due to interspecific inconsistency in population dynamic responses to climate change. However, it may still be possible to predict abundance change for species based on a robust understanding of relationships between their population dynamics and phenology, and the environmental drivers of both.Royal SocietyNatural Environment Research Counci

    Unveiling the planet population at birth

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    The radius distribution of small, close-in exoplanets has recently been shown to be bimodal. The photoevaporation model predicted this bimodality. In the photoevaporation scenario, some planets are completely stripped of their primordial H/He atmospheres, whereas others retain them. Comparisons between the photoevaporation model and observed planetary populations have the power to unveil details of the planet population inaccessible by standard observations, such as the core mass distribution and core composition. In this work, we present a hierarchical inference analysis on the distribution of close-in exoplanets using forward models of photoevaporation evolution. We use this model to constrain the planetary distributions for core composition, core mass, and initial atmospheric mass fraction. We find that the core-mass distribution is peaked, with a peak-mass of ∼4M⊕. The bulk core-composition is consistent with a rock/iron mixture that is ice-poor and ‘Earth-like’; the spread in core-composition is found to be narrow (⁠≲16 per cent variation in iron-mass fraction at the 2σ level) and consistent with zero. This result favours core formation in a water/ice poor environment. We find the majority of planets accreted a H/He envelope with a typical mass fraction of ∼4 per cent⁠; only a small fraction did not accrete large amounts of H/He and were ‘born-rocky’. We find four times as many super-Earths were formed through photoevaporation, as formed without a large H/He atmosphere. Finally, we find core-accretion theory overpredicts the amount of H/He cores would have accreted by a factor of ∼5, pointing to additional mass-loss mechanisms (e.g. ‘boil-off’) or modifications to core-accretion theory

    Band structure engineering in (Bi1-xSbx)2Te3 ternary topological insulators

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    Three-dimensional (3D) topological insulators (TI) are novel quantum materials with insulating bulk and topologically protected metallic surfaces with Dirac-like band structure. The spin-helical Dirac surface states are expected to host exotic topological quantum effects and find applications in spintronics and quantum computation. The experimental realization of these ideas requires fabrication of versatile devices based on bulk-insulating TIs with tunable surface states. The main challenge facing the current TI materials exemplified by Bi2Se3 and Bi2Te3 is the significant bulk conduction, which remains unsolved despite extensive efforts involving nanostructuring, chemical doping and electrical gating. Here we report a novel approach for engineering the band structure of TIs by molecular beam epitaxy (MBE) growth of (Bi1-xSbx)2Te3 ternary compounds. Angle-resolved photoemission spectroscopy (ARPES) and transport measurements show that the topological surface states exist over the entire composition range of (Bi1-xSbx)2Te3 (x = 0 to 1), indicating the robustness of bulk Z2 topology. Most remarkably, the systematic band engineering leads to ideal TIs with truly insulating bulk and tunable surface state across the Dirac point that behave like one quarter of graphene. This work demonstrates a new route to achieving intrinsic quantum transport of the topological surface states and designing conceptually new TI devices with well-established semiconductor technology.Comment: Minor changes in title, text and figures. Supplementary information adde

    Nemo: a computational tool for analyzing nematode locomotion

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    The nematode Caenorhabditis elegans responds to an impressive range of chemical, mechanical and thermal stimuli and is extensively used to investigate the molecular mechanisms that mediate chemosensation, mechanotransduction and thermosensation. The main behavioral output of these responses is manifested as alterations in animal locomotion. Monitoring and examination of such alterations requires tools to capture and quantify features of nematode movement. In this paper, we introduce Nemo (nematode movement), a computationally efficient and robust two-dimensional object tracking algorithm for automated detection and analysis of C. elegans locomotion. This algorithm enables precise measurement and feature extraction of nematode movement components. In addition, we develop a Graphical User Interface designed to facilitate processing and interpretation of movement data. While, in this study, we focus on the simple sinusoidal locomotion of C. elegans, our approach can be readily adapted to handle complicated locomotory behaviour patterns by including additional movement characteristics and parameters subject to quantification. Our software tool offers the capacity to extract, analyze and measure nematode locomotion features by processing simple video files. By allowing precise and quantitative assessment of behavioral traits, this tool will assist the genetic dissection and elucidation of the molecular mechanisms underlying specific behavioral responses.Comment: 12 pages, 2 figures. accepted by BMC Neuroscience 2007, 8:8

    Gate-tuned normal and superconducting transport at the surface of a topological insulator

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    Three-dimensional topological insulators are characterized by the presence of a bandgap in their bulk and gapless Dirac fermions at their surfaces. New physical phenomena originating from the presence of the Dirac fermions are predicted to occur, and to be experimentally accessible via transport measurements in suitably designed electronic devices. Here we study transport through superconducting junctions fabricated on thin Bi2Se3 single crystals, equipped with a gate electrode. In the presence of perpendicular magnetic field B, sweeping the gate voltage enables us to observe the filling of the Dirac fermion Landau levels, whose character evolves continuously from electron- to hole-like. When B=0, a supercurrent appears, whose magnitude can be gate tuned, and is minimum at the charge neutrality point determined from the Landau level filling. Our results demonstrate how gated nano-electronic devices give control over normal and superconducting transport of Dirac fermions at an individual surface of a three-dimensional topological insulator.Comment: 28 pages, 5 figure
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