9,139 research outputs found

    Retransmission of Hydrometric Data in Canada

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    There are no author-identified significant results in this report

    Impact of droop and scarf on the aerodynamic performance of compact aero-engine nacelles

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    Future turbofan engines will operate with larger engine bypass-ratios and lower specific thrust than current in-service architectures to reduce the specific fuel consumption. This will be achieved by increasing the fan diameter which will incur in an increment in nacelle size and a concomitant larger nacelle drag, weight and interaction effects with the airframe. Therefore, it is required to design compact nacelles which will not counteract the benefits obtained from the new engine cycles. Nacelle design is based on a set of aero-lines that in combination with droop and scarf result in a 3D design. Traditionally, this process was performed by the design of axisymmetric aero-lines. Nevertheless, there is an emerging need to carry out the design process for full 3D configurations to have a better understanding of the effect of droop and scarf angles on the nacelle drag characteristics. This paper presents a numerical method for the multi-objective optimisation of drooped and scarfed non-axisymmetric nacelle aero-engines. It uses intuitive Class Shape Tranformations (iCSTs) for the aero-engine geometry definition, multi-point aerodynamic simulation, a near-field nacelle drag extraction method and the NSGA-II genetic algorithm. The process has been employed to perform independent multi-objective optimisations of compact architectures at selected droop and scarf angle combinations. The multi-objective optimisation framework was successfully demonstrated for the new nacelle design challenge and the overall system was shown to enable the identification of the effects of droop and scarf on compact aero-engines. The proposed tool complements a set of technologies for the design, analysis and optimisation of future civil turbofans aiming at reduction of specific fuel consumption

    The state of Florida's estuaries and future needs in estuarine research: Part 2. an academic research agenda (review draft)

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    As a program supporting academic research that addresses recognized societal needs, the Florida Sea Grant Program is developing a research theme area on estuaries to provide a uniquely academic product that will augment mission-oriented research undertaken by government and by the private sector. This report is not a call for proposals. It does not prescribe a specific research plan. Rather, it is a concept paper designed to focus research on two broad "organizing themes": (1) the hydrology of Florida's estuaries, and (2) the impact of cyclic environmental variability on estuarine function. (46pp.

    Sensing the cilium, digital capture of ciliary data for comparative genomics investigations.

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    Cilia are specialized, hair-like structures that project from the cell bodies of eukaryotic cells. With increased understanding of the distribution and functions of various types of cilia, interest in these organelles is accelerating. To effectively use this great expansion in knowledge, this information must be made digitally accessible and available for large-scale analytical and computational investigation. Capture and integration of knowledge about cilia into existing knowledge bases, thus providing the ability to improve comparative genomic data analysis, is the objective of this work. Cilia 2018; 7:3

    Safety and pharmacokinetics of dolutegravir in HIV-positive pregnant women: a systematic review

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    Background: The integrase strand transfer inhibitor dolutegravir (DTG) is being introduced into low- and middle-income countries (LMICs) as an alternative to first-line treatment with non-nucleoside reverse transcriptase inhibitors. However, DTG is not yet widely recommended for use in pregnant women. The aim of this systematic review was to analyse all available data on birth outcomes and congenital anomalies in the infants of pregnant women treated with DTG. Methods: A PubMed and Embase search was conducted using the terms "dolutegravir" or "DTG" and "pregnancy" or "pregnant" from the earliest available date on the database to 26 July 2017. Any reports involving women who were pregnant, HIV positive and taking DTG were included. The percentage of pregnant women with adverse birth outcomes or congenital anomalies in their infants after taking dolutegravir was compared with five historical control databases. Results: There were six databases included in the main analysis of birth outcomes and congenital anomalies, with a total of 1200 pregnant women. The percentage of pregnant women taking DTG with adverse birth outcomes and congenital abnormalities was similar to results from historical control studies of HIV-positive women. However, there was significant heterogeneity among the six databases - the percentage of infants with congenital anomalies ranged from 0.0% in Botswana (0/116 infants) to 13.3% in IMPAACT P1026S (2/15 infants). Conclusions: Up to 15 million people could be on treatment with DTG in LMICs within the next 5 years, of whom a substantial percentage is likely to be women of child-bearing potential. In many countries with large HIV epidemics, unplanned pregnancies are common and access to antenatal clinic facilities may be limited. Continued pharmacovigilance is essential, but it is reassuring that no clear safety signals have been detected, to date, for pregnant women treated with DTG in terms of birth outcomes or congenital anomalies

    Modelling the atomic structure of very high-density amorphous ice

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    The structure of very high-density amorphous (VHDA) ice has been modelled by positionally disordering three crystalline phases, namely ice IV, VI and XII. These phases were chosen because only they are stable or metastable in the region of the ice phase diagram where VHDA ice is formed, and their densities are comparable to that of VHDA ice. An excellent fit to the medium range of the experimentally observed pair-correlation function g(r) of VHDA ice was obtained by introducing disorder into the positions of the H2O molecules, as well as small amounts of molecular rotational disorder, disorder in the O--H bond lengths and disorder in the H--O--H bond angles. The low-k behaviour of the experimental structure factor, S(k), is also very well reproduced by this disordered-crystal model. The fraction of each phase present in the best-fit disordered model is very close to that observed in the probable crystallization products of VHDA ice. In particular, only negligible amounts of ice IV are predicted, in accordance with experimental observation.Comment: 4 pages, 3 figures, 1 table, v2: changes made in response to referees' comments, the justification for using certain ice phases is improved, and ice IV is now disordered as wel

    Investigating benchmark correlations when comparing algorithms with parameter tuning: detailed experiments and results.

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    Benchmarks are important to demonstrate the utility of optimisation algorithms, but there is controversy about the practice of benchmarking; we could select instances that present our algorithm favourably, and dismiss those on which our algorithm underperforms. Several papers highlight the pitfalls concerned with benchmarking, some of which concern the context of the automated design of algorithms, where we use a set of problem instances (benchmarks) to train our algorithm. As with machine learning, if the training set does not reflect the test set, the algorithm will not generalize. This raises some open questions concerning the use of test instances to automatically design algorithms. We use differential evolution and sweep the parameter settings to investigate the practice of benchmarking using the BBOB benchmarks. We make three key findings. Firstly, several benchmark functions are highly correlated. This may lead to the false conclusion that an algorithm performs well in general, when it performs poorly on a few key instances, possibly introducing unwanted bias to a resulting automatically designed algorithm. Secondly, the number of evaluations can have a large effect on the conclusion. Finally, a systematic sweep of the parameters shows how performance varies with time across the space of algorithm configurations. The datasets, including all computed features, the evolved policies and their performances, and the visualisations for all feature sets are available from the University of Stirling Data Repository (http://hdl.handle.net/11667/109)

    Universal screening for meticillin-resistant Staphylococcus aureus : interim results from the NHS Scotland pathfinder project

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    Following recommendations from a Health Technology Assessment (HTA), a prospective cohort study of meticillin-resistant Staphylococcus aureus (MRSA) screening of all admissions (N = 29 690) to six acute hospitals in three regions in Scotland indicated that 7.5% of patientswere colonised on admission to hospital. Factors associated with colonisation included re-admission, specialty of admission (highest in nephrology, care of the elderly, dermatology and vascular surgery), increasing age, and the source of admission (care home or other hospital). Three percent of all those who were identified as colonised developed hospital-associated MRSA infection, compared with only 0.1% of those not colonised. Specialtieswith a high rate of colonisation on admission also had higher rates of MRSA infection. Very few patients refused screening (11 patients, 0.03%) or had treatment deferred (14 patients, 0.05%). Several organisational issues were identified, including difficulties in achieving complete uptake of screening (88%) or decolonisation (41%); the latter was largely due to short duration of stay and turnaround time for test results. Patient movement resulted in a decision to decontaminate all positive patients rather than just those in high risk specialties as proposed by the HTA. Issues also included a lack of isolation facilities to manage patients with MRSA. The study raises significant concerns about the contribution of decolonisation to reducing risks in hospital due to short duration of stay, and reinforces the central role of infection control precautions. Further study is required before the HTA model can be re-run and conclusions redrawn on the cost and clinical effectiveness of universal MRSA screening
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