1,500 research outputs found

    Gust Alleviation System for General Aviation Aircraft

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    A designed control motion scheme to improve passenger comfort in general aviation aircraft by reducing normal acceleration and pitch rate due to turbulence is investigated. An aerodynamic math model is created for ViGYAN’s Active Ride Improvement System flight article, a one-eighth scale Pilatus Porter PC-6 with conventional forward main wing, aft horizontal and vertical tails, and a single engine with tractor configuration. The test article incorporates a full-span gust flap and forward mounted gust sensor to mechanize the gust alleviation control system, and these features are present in the dynamic model. The model is a two degree of freedom linear pitch-plunge description of the flight dynamics and is enhanced by including separate gust effects and indicial lifts. Three wind fields are input to the model for linear simulation testing with the controls both fixed and active, and comparisons are drawn for alleviations in the human motion sickness range. The system successfully produced nearly an order of magnitude reduction in normal acceleration and an order of magnitude reduction in pitch rate. This gust alleviation performance shows that the ride improvement concept appears feasible by offering significant improvement in passenger comfort in general aviation aircraft experiencing turbulence with practical engineering implementation

    A reconnaissance of pollution of the King River in the Comstock-Crotty area, west Tasmania

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    In November 1974 ,an investigation was made of the King River through the stretch from just above its junction with Comstock Creek to just above its junction with the Governor River. Sampling stations were selected at nine sites, six on the King River, one on Linda Creek, one on Comstock Creek and one on the Governor River. At each station, samples were taken of the water, of the sediments and of the benthic macro­invertebrates. Analysis of the sediment samples provided good evidence that the King River is polluted from Comstock Creek downstream, with copper and, to a lesser extent, lead and zinc. This pollution is clearly indicated in the distribution of the riffle-­dwelling macroinvertebrates and of trout. The Governor River and the King River up­stream of Comstock Creek are not polluted. A 24-hour sampling of the drift fauna in the King River just above and just below the entry of Comstock Creek showed a surprising drop in the abundance of the drift with the entry of pollution. The results of the survey are discussed in the light of overseas work on stream sediments and Australian and overseas work on the effects of metal pollution on stream fauna. The pollution, even if steps are made to abate it, is likely to persist for a very long time

    Cost-Effectiveness of Malaria Diagnosis in Sub-Saharan Africa: The Role of Rapid Diagnostic Tests. Report submitted to WHO

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    Objective To evaluate the relative cost-effectiveness in different sub-Saharan African settings of presumptive treatment, field-standard microscopy and rapid diagnostic tests (RDTs) to diagnose malaria. Methods We used a decision tree model and probabilistic sensitivity analysis applied to outpatients presenting at rural health facilities with suspected malaria. Costs and effects encompassed those for both patients positive on RDT (assuming artemisinin-based combination therapy) and febrile patients negative on RDT (assuming antibiotic treatment). Interventions were defined as cost-effective if they were less costly and more effective or had an incremental cost per disability-adjusted life year averted of less than US$ 150. Data were drawn from published and unpublished sources, supplemented with expert opinion. Findings RDTs were cost-effective compared with presumptive treatment up to high prevalences of Plasmodium falciparum parasitaemia. Decision-makers can be at least 50% confident of this result below 81% malaria prevalence, and 95% confident below 62% prevalence, a level seldom exceeded in practice. RDTs were more than 50% likely to be cost-saving below 58% prevalence. Relative to microscopy, RDTs were more than 85% likely to be cost-effective across all prevalence levels, reflecting their expected better accuracy under real-life conditions. Results were robust to extensive sensitivity analysis. The cost-effectiveness of RDTs mainly reflected improved treatment and health outcomes for non-malarial febrile illness, plus savings in antimalarial drug costs. Results were dependent on the assumption that prescribers used test results to guide treatment decisions. Conclusion RDTs have the potential to be cost-effective in most parts of sub-Saharan Africa. Appropriate management of malaria and non-malarial febrile illnesses is required to reap the full benefits of these tests

    The effect of a single 30-minute bout of moderate intensity intermittent exercise on the inflammatory response in breast cancer survivors

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    This retrospective study examined the effect of an acute 30-minute bout of moderate intensity intermittent exercise on inflammatory markers (TNF-­‐α, CRP, and IL-10) in breast cancer survivors and healthy controls. Relationships between inflammatory markers and NK cell count were also explored. Eighteen subjects (9 breast cancer survivors, 9 healthy controls) completed the study. Markers of inflammation and NK cell count were analyzed from blood samples taken at pre-exercise, immediately post-exercise, 2 hours post-exercise, and 24 hours post-exercise. There were no significant changes in inflammatory markers across time for both groups (p > 0.05). There were no significant relationships between changes in inflammatory markers and NK cell across time (p > 0.05). In conclusion, both groups responded similarly to the acute bout of exercise relating to markers of inflammation, and from this sample changes in NK cell did not seem to be mediated by the inflammatory response.Master of Art

    Zircon U-Pb geochronology of the Mount Givens Granodiorite: Implications for the genesis of large volumes of eruptible magma

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    The Mount Givens Granodiorite, a large pluton in the central Sierra Nevada batholith, California, is similar in area to zoned intrusive suites yet is comparatively chemically and texturally homogenous. New zircon U-Pb geochronology indicates that the pluton was constructed over at least 7 Ma from 97.92 ± 0.06 Ma to 90.87 ± 0.05 Ma. Combining the new geochronology with the exposed volume of the pluton yields an estimated magma flux of <0.001 km3/a. The geochronologic data are at odds with the previously speculated links between plutons such as the Mount Givens Granodiorite and large-volume homogeneous ignimbrites (often termed monotonous intermediates). Existing data indicate that large plutons accumulate at rates of ≀0.001 km3/a, 1-2 orders of magnitude less than fluxes calculated for dated monotonous intermediates. If monotonous intermediates are remobilized, erupted plutons accumulated at rates comparable to dated examples, they should preserve a record of zircon growth of up to 10 Ma. Alternatively, the long history of zircon growth recorded in plutons may be erased during the processes of reheating and remobilization that precede supervolcano eruption. However, zircon dissolution modeling, based on hypothetical temperature-time histories for preeruptive monotonous intermediates, indicates that rejuvenation events would not sufficiently dissolve zircon. We suggest that eruptions of monotonous intermediates occur during high magmatic flux events, leaving little behind in the intrusive rock record, whereas low fluxes favor pluton accumulation

    The pace of plutonism

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    Beneath volcanoes are magmas that never erupt but that become frozen into feldspar- and quartz-rich rocks broadly called granite. Where the crystallized magmas form bodies with distinctive textures, they are grouped into named units-plutons. The rate (pace) at which magmas accumulate into plutons is fundamental to understanding both how room is made for the magmas and how unerupted and erupted magmas are connected. Dating plutonic rocks suggests that plutons accumulate slowly. Although the pace of magma accumulation does not preclude direct connections between plutons and small volcanic eruptions, it appears to be far too slow to support connections between most plutons and supereruptions

    High-Intensity and High-Brightness Source of Moderated Positrons Using a Brilliant gamma Beam

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    Presently large efforts are conducted towards the development of highly brilliant gamma beams via Compton back scattering of photons from a high-brilliance electron beam, either on the basis of a normal-conducting electron linac or a (superconducting) Energy Recovery Linac (ERL). Particularly ERL's provide an extremely brilliant electron beam, thus enabling to generate highest-quality gamma beams. A 2.5 MeV gamma beam with an envisaged intensity of 10^15 s^-1, as ultimately envisaged for an ERL-based gamma-beam facility, narrow band width (10^-3), and extremely low emittance (10^-4 mm^2 mrad^2) offers the possibility to produce a high-intensity bright polarized positron beam. Pair production in a face-on irradiated W converter foil (200 micron thick, 10 mm long) would lead to the emission of 2 x 10^13 (fast) positrons per second, which is four orders of magnitude higher compared to strong radioactive ^22Na sources conventionally used in the laboratory.Using a stack of converter foils and subsequent positron moderation, a high-intensity low-energy beam of moderated positrons can be produced. Two different source setups are presented: a high-brightness positron beam with a diameter as low as 0.2 mm, and a high-intensity beam of 3 x 10^11 moderated positrons per second. Hence, profiting from an improved moderation efficiency, the envisaged positron intensity would exceed that of present high-intensity positron sources by a factor of 100.Comment: 9 pages, 3 figure

    The plutonic record of a silicic ignimbrite from the Latir volcanic field, New Mexico

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    Zircon U-Pb geochronologic data for plutonic rocks in the Latir volcanic field, New Mexico, demonstrate that the rocks are dominated by plutons that post-date ignimbrite eruption. Only zircon from the ring dike of the Questa caldera yields the same age (25.64±0.08 Ma) as zircon from the caldera-forming Amalia Tuff (25.52±0.06 Ma). The post-caldera Rio Hondo pluton was assembled incrementally over at least 400 ka. The magma accumulation rate for the exposed portion of the Rio Hondo pluton is estimated to be 0.0003 km3 a-1, comparable to rates for other plutons, and too slow to support accumulation of large eruptible magma volumes. Extrapolation of the accumulation rate for the Rio Hondo pluton over the history of the Latir volcanic field yields an estimated volume of plutonic rocks comparable to the calculated volume under the field as determined by geophysical studies. We propose that the bulk of the plutonic rocks beneath the volcanic center accumulated during periods of low volcanic effusivity. Furthermore, because the oldest portion of the Rio Hondo pluton is the granitic cap exposed beneath a gently dipping roof contact, the roof granite cannot be a silicic liquid fractionated from the deeper (younger) portions of the pluton. Instead, our data suggest that the compositional heterogeneity of the Rio Hondo pluton is inherited from lower crustal sources. We suggest that if magma fluxes are high enough, zoned ignimbrites can be formed by evolution of the melt compositions generated at the source with little or no shallow crustal differentiation

    Developing fit-for-purpose funding models for rural settings: Lessons from the evaluation of a step-up/step-down service in regional Australia

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    IntroductionSub-acute mental health community services provide a bridging service between hospital and community care. There is limited understanding of the local factors that influence success, and of the funding implications of delivering services in rural areas.MethodsThis paper draws from quantitative and qualitative evaluation data from a regional Western Australian service to explore these issues.ResultsConsumers satisfaction with the service was high and, overall, admission to the service resulted in positive outcomes. High re-admission rates may be linked to limited community support services following discharge.DiscussionOur results suggest that outcomes may be enhanced by implementing flexible approaches that address the resource limitations of the rural context, and that the current funding model for sub-acute mental health services in rural Australian may not be fit for purpose. More needs to be understood about how these services can be better integrated with existing support services, and how they can be better funded

    Genetic Variants of PTPN2 are Associated with Lung Cancer Risk: a Re-Analysis of Eight GWASs in the TRICL-ILCCO Consortium

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    The T-cell protein tyrosine phosphatase (TCPTP) pathway consists of signaling events mediated by TCPTP. Mutations and genetic variants of some genes in the TCPTP pathway are associated with lung cancer risk and survival. In the present study, we first investigated associations of 5,162 single nucleotide polymorphisms (SNPs) in 43 genes of this TCPTP pathway with lung cancer risk by using summary data of six published genome-wide association studies (GWAS) of 12,160 cases and 16,838 controls. We identified 11 independent SNPs in eight genes after correction for multiple comparisons by a false discovery rate \u3c 0.20. Then, we performed in silico functional analyses for these 11 SNPs by eQTL analysis, two of which, PTPN2 SNPs rs2847297 and rs2847282, were chosen as tagSNPs. We further included two additional GWAS datasets of Harvard University (984 cases and 970 controls) and deCODE (1,319 cases and 26,380 controls), and the overall effects of these two SNPs among all eight GWAS studies remained significant (OR = 0.95, 95% CI = 0.92–0.98, and P = 0.004 for rs2847297; OR = 0.95, 95% CI = 0.92–0.99, and P = 0.009 for rs2847282). In conclusion, the PTPN2 rs2847297 and rs2847282 may be potential susceptible loci for lung cancer risk
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