6,971 research outputs found

    Helicopter Pilot Performance for Discrete-maneuver Flight Tasks

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    This paper describes a current study of several basic helicopter flight maneuvers. The data base consists of in-flight measurements from instrumented helicopters using experienced pilots. The analysis technique is simple enough to apply without automatic data processing, and the results can be used to build quantitative matah models of the flight task and some aspects of the pilot control strategy. In addition to describing the performance measurement technqiue, some results are presented which define the aggressiveness and amplitude of maneuvering for several lateral maneuvers including turns and sidesteps

    Transient and steady-state velocity of domain walls for a complete range of drive fields

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    Approximate analytic solutions for transient and steady-state 180 deg domain wall motion in bulk magnetic material are obtained from the dynamic torque equations with a Gilbert damping term. The results for the Walker region in which the transient solution approaches the familiar Walker steady-state solution are presented in a slightly new form for completeness. An analytic solution corresponding to larger drive fields predicts an oscillatory motion with an average value which decreases with drive field for reasonable values of the damping parameter. These results agree with those obtained by a computer solution of the torque equation and those obtained with the assumption of a very large anisotropy field

    Wall contraction in Bloch wall films

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    The phenomenon of wall contraction characterized by a peak in the velocity field relationship and a region of negative differential mobility is observed. Uniaxial magnetic thin films of various compositions and magnetic properties are studied in careful interrupted pulse experiments. The observed results agree quite well with the theory for bulk samples

    Stoicism.

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    Establishing microbial baselines to identify indicators of coral reef health

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    Microorganisms make a significant contribution to reef ecosystem health and resilience via their critical role in mediating nutrient transformations, their interactions with macro-organisms and their provision of chemical cues that underpin the recruitment of diverse reef taxa. However, environmental changes often cause compositional and functional shifts in microbial communities that can have flow-on consequences for microbial-mediated processes. These microbial alterations may impact the health of specific host organisms and can have repercussions for the functioning of entire coral ecosystems. Assessing changes in reef microbial communities should therefore provide an early indicator of ecosystem impacts and would underpin the development of diagnostic tools that could help forecast shifts in coral reef health under different environmental states. Monitoring, management and active restoration efforts have recently intensified and diversified in response to global declines in coral reef health. Here we propose that regular monitoring of coral reef microorganisms could provide a rapid and sensitive platform for identifying declining ecosystem health that can complement existing management frameworks. By summarising the most common threats to coral reefs, with a particular focus on the Great Barrier Reef, and elaborating on the role of microbes in coral reef health and ecosystem stability, we highlight the diagnostic applicability of microbes in reef management programs. Fundamental to this objective is the establishment of microbial baselines for Australia's coral reefs.AIMS@JCU PhD Scholarship; GBRMPA Science Management Research Award; Advance Queensland PhD Scholarship; Portuguese Science and Technology Foundation (FCT) [SFRH/BPD/110285/2015

    Low frequency creep in CoNiFe films

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    The results of an investigation of domain wall motion excited by slow rise-time, bipolar, hard-axis pulses in vacuum deposited CoNiFe films 1500A to 2000A thick are presented. The results are consistent with those of comparable NiFe films in spite of large differences in film properties. The present low frequency creep data together with previously published results in this and other laboratories can be accounted for by a model which requires that the wall structure change usually associated with low frequency creep be predominately a gyromagnetic process. The correctness of this model is reinforced by the observation that the wall coercive force, the planar wall mobility, and the occurrence of an abrupt wall structure change are the only properties closely correlated to the creep displacement characteristics of a planar wall in low dispersion films

    Do earplugs stop noise from driving critical care patients into delirium?

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    Quality sleep is a problem for the critically ill who are cared for in an environment where interventions night and day are common, staff members are constantly present in relatively high numbers, and treatment is accompanied by a range of changing warning tones and alarms and lights. These critical care units are generally designed without a focus on patient comfort, sleep, and rest and often lack access to appropriate natural daylight. To add to this problem, critical illness, particularly sepsis, disrupts circadian rhythms and sleep patterns, and disruption of circadian rhythms, in turn, impairs immunity and contributes to delirium. In a randomized controlled trial in the previous issue of Critical Care, Van Rompaey and colleagues have intervened to reduce noise, which is a key factor in this disruption, by having patients use earplugs at night. Delirium was assessed by using the NEECHAM (Neelon and Champagne) confusion scale, and sleep perception was assessed by patients' responses to a set of five questions. After the first night, patients reported a better sleep perception and the occurrence of delirium was reduced (hazard ratio of 0.47 for the development of delirium) or was delayed. The study did not quantify adequacy of pain control in post-surgical patients and used patient reporting to assess sleep. Whether patients were receiving respiratory or other organ support was not reported. The potential benefit of earplugs is an important practical finding that could be implemented in most intensive care units

    T-PHOT version 2.0: improved algorithms for background subtraction, local convolution, kernel registration, and new options

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    We present the new release v2.0 of T-PHOT, a publicly available software package developed to perform PSF-matched, prior-based, multiwavelength deconfusion photometry of extragalactic fields. New features included in the code are presented and discussed: background estimation, fitting using position dependent kernels, flux prioring, diagnostical statistics on the residual image, exclusion of selected sources from the model and residual images, individual registration of fitted objects. These new options improve on the performance of the code, allowing for more accurate results and providing useful aids for diagnostics.Comment: 7 pages, 8 figure

    Soil acidity in the eastern wheatbelt.

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    Effect of profile acidity on nutrient and water use by wheat, 85M48. Effect of liming a wodjil soil prile on lupin production, 82ME10 and 82M5 . Lime banding in acid subsoils for wheat, 81M54. Liming topsoil. Rates of lime on wheat, 80M30. Residual value of lime (lupins 1985) 80M31. Survey Survey of extremely poor eastern wheatbelt yellow earth soils, 85ME9
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