3,316 research outputs found

    On the relationships between self-reported bicycling injuries and perceived risk among cyclists in Queensland, Australia

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    The focus of governments on increasing active travel has motivated renewed interest in cycling safety. Bicyclists are up to 20 times more likely to be involved in serious injury crashes than drivers so understanding the relationship among factors in bicyclist crash risk is critically important for identifying effective policy tools, for informing bicycle infrastructure investments, and for identifying high risk bicycling contexts. This study aims to better understand the complex relationships between bicyclist self reported injuries resulting from crashes (e.g. hitting a car) and non-crashes (e.g. spraining an ankle) and perceived risk of cycling as a function of cyclist exposure, rider conspicuity, riding environment, rider risk aversion, and rider ability. Self reported data from 2,500 Queensland cyclists are used to estimate a series of seemingly unrelated regressions to examine the relationships among factors. The major findings suggest that perceived risk does not appear to influence injury rates, nor do injury rates influence perceived risks of cycling. Riders who perceive cycling as risky tend not to be commuters, do not engage in group riding, tend to always wear mandatory helmets and front lights, and lower their perception of risk by increasing days per week of riding and by increasing riding proportion on bicycle paths. Riders who always wear helmets have lower crash injury risk. Increasing the number of days per week riding tends to decrease both crash injury and non crash injury risk (e.g. a sprain). Further work is needed to replicate some of the findings in this study

    Microscopic Investigation of Vortex Breakdown in a Dividing T-Junction Flow

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    3D-printed microfluidic devices offer new ways to study fluid dynamics. We present the first clear visualization of vortex breakdown in a dividing T-junction flow. By individual control of the inflow and two outflows, we decouple the effects of swirl and rate of vorticity decay. We show that even slight outflow imbalances can greatly alter the structure of vortex breakdown, by creating a net pressure difference across the junction. Our results are summarized in a dimensionless phase diagram, which will guide the use of vortex breakdown in T-junctions to achieve specific flow manipulation.Comment: 5 pages, 5 figure

    Chronic helminth infection burden differentially affects haematopoietic cell development while ageing selectively impairs adaptive responses to infection

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    Throughout the lifespan of an individual, the immune system undergoes complex changes while facing novel and chronic infections. Helminths, which infect over one billion people and impose heavy livestock productivity losses, typically cause chronic infections by avoiding and suppressing host immunity. Yet, how age affects immune responses to lifelong parasitic infection is poorly understood. To disentangle the processes involved, we employed supervised statistical learning techniques to identify which factors among haematopoietic stem and progenitor cells (HSPC), and both innate and adaptive responses regulate parasite burdens and how they are affected by host age. Older mice harboured greater numbers of the parasites’ offspring than younger mice. Protective immune responses that did not vary with age were dominated by HSPC, while ageing specifically eroded adaptive immunity, with reduced numbers of naïve T cells, poor T cell responsiveness to parasites, and impaired antibody production. We identified immune factors consistent with previously-reported immune responses to helminths, and also revealed novel interactions between helminths and HSPC maturation. Our approach thus allowed disentangling the concurrent effects of ageing and infection across the full maturation cycle of the immune response and highlights the potential of such approaches to improve understanding of the immune system within the whole organism

    Western Extended Techniques in Traditional Japanese Wind Performance: Gagaku Kangen and Shakuhachi Honkyoku

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    The term “extended techniques” in the context of Western art music refers to performance techniques that fall outside the normal course of study for an instrument. The purpose of this study is, 1) to show that woodwind techniques considered “extended” and relatively “new” in Western classical music appear in traditional repertoires in Japan, and 2) to show that these techniques do not function as merely ornamental or virtuosic devices, but are instead structurally significant. I approach these two objectives through case studies of the instrumental kangen repertoire of the gagaku court ensemble (with a focus on the hichiriki and ryĆ«teki wind parts) and the classical Zen Buddhist honkyoku repertoire of the shakuhachi flute. Whereas previous studies have disregarded the role of performance techniques in their analyses of form and mode, I have investigated how performance techniques confirm, emphasize, and even outline the formal and modal structure of the case-study pieces: Etenraku (gagaku) and Sokaku Reibo (shakuhachi). In this study, I analyze two recordings of the virtuosic shakuhachi piece Sokaku Reibo by recognized masters: Aoki Reibo II and Yamaguchi Gorƍ, and three recordings of the well-known gagaku piece Etenraku by Japanese court ensembles, in addition to recordings of the individual wind parts and sung mnemonics. In order to create a comprehensive picture of the role of the relevant performance techniques, I combine the methods of transnotation of tablature scores and mnemonics into staff notation (and lists of pitch cells in the case of Sokaku Reibo), transcription of recordings, and spectral analysis of recorded excerpts. This study demonstrates that all elements of a performance should be considered in analysis. An analysis that considers only the basic melodic line of a piece risks discarding elements that could inform and confirm the results. In the case of Etenraku and Sokaku Reibo, my investigation of performance techniques has led to a discovery of their structural significance

    Science and Deep Space Missions

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    Have you ever wondered about the science goals of various deep space missions? Or why scientists want such seemingly complicated spacecraft and operations scenarios? With a focus on outer planets) this talk will cover the scientific goals and results of several recent and future missions) how scientists approach a requirements flow down) and how the disparate needs of mission engineers and scientists can come together for mission success. It will also touch on several up and coming technologies and how they will change mission architectures in the future

    Meteorology of Jupiter's Equatorial Hot Spots and Plumes from Cassini

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    We present an updated analysis of Jupiter's equatorial meteorology from Cassini observations. For two months preceding the spacecraft's closest approach, the Imaging Science Subsystem (ISS) onboard regularly imaged the atmosphere. We created time-lapse movies from this period in order to analyze the dynamics of equatorial hot spots and their interactions with adjacent latitudes. Hot spots are quasi-stable, rectangular dark areas on visible-wavelength images, with defined eastern edges that sharply contrast with surrounding clouds, but diffuse western edges serving as nebulous boundaries with adjacent equatorial plumes. Hot spots exhibit significant variations in size and shape over timescales of days and weeks. Some of these changes correspond with passing vortex systems from adjacent latitudes interacting with hot spots. Strong anticyclonic gyres present to the south and southeast of the dark areas appear to circulate into hot spots. Impressive, bright white plumes occupy spaces in between hot spots. Compact cirrus-like 'scooter' clouds flow rapidly through the plumes before disappearing within the dark areas. These clouds travel at 150-200 m/s, much faster than the 100 m/s hot spot and plume drift speed. This raises the possibility that the scooter clouds may be more illustrative of the actual jet stream speed at these latitudes. Most previously published zonal wind profiles represent the drift speed of the hot spots at their latitude from pattern matching of the entire longitudinal image strip. If a downward branch of an equatorially-trapped Rossby waves controls the overall appearance of hot spots, however, the westward phase velocity of the wave leads to underestimates of the true jet stream speed.Comment: 33 pages, 11 figures; accepted for publication in Icarus; for supplementary movies, please contact autho

    Solvent responsive catalyst improves NMR sensitivity via efficient magnetisation transfer

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    A bidentate iridium carbene complex, Ir(ÎșC,O-L1)(COD), has been synthesised which contains a strongly electron donating carbene ligand that is functionalised by a cis-spanning phenolate group. This complex acts as a precursor to effective magnetisation transfer catalysts which form after reaction with H2 and a suitable two electron donor. In solvents such as benzene, containing pyridine, they are exemplified by neutral, chiral Ir(H)2(ÎșC,O-L1)(py)2 with inequivalent hydride ligands and Ir-O bond retention, whilst in methanol, Ir-O bond cleavage leads to zwitterionic [Ir(H)2(ÎșC,O−-L1)(py)3]+, with chemically equivalent hydride ligands. The active catalyst’s form is therefore solvent dependent. Both these complexes break the magnetic symmetry of the hydride ligands and are active in the catalytic transfer of polarisation from parahydrogen to a loosely bound ligand. Test results on pyridine, nicotinaldehyde and nicotine reveal up to ≈ 1.2 % single spin proton polarisation levels in their 1H signals which compare to the normal 0.003% level at 9.4 Tesla. These results exemplify how rational catalyst design yields a solvent dependent catalyst with good SABRE activity

    Probing the Superfluid to Mott Insulator Transition at the Single Atom Level

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    Quantum gases in optical lattices offer an opportunity to experimentally realize and explore condensed matter models in a clean, tunable system. We investigate the Bose-Hubbard model on a microscopic level using single atom-single lattice site imaging; our technique enables space- and time-resolved characterization of the number statistics across the superfluid-Mott insulator quantum phase transition. Site-resolved probing of fluctuations provides us with a sensitive local thermometer, allows us to identify microscopic heterostructures of low entropy Mott domains, and enables us to measure local quantum dynamics, revealing surprisingly fast transition timescales. Our results may serve as a benchmark for theoretical studies of quantum dynamics, and may guide the engineering of low entropy phases in a lattice
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