1,017 research outputs found
Drag reduction for gliders
The article discusses the causes of drag in gliders. The importance of maintaining laminar flow is emphasized. The problems of surface (or lack of) smoothness are outlined
A possibility of avoiding surface roughness due to insects
Discussion of a method for eliminating turbulence caused by the formation of insect roughness upon the leading edges and fuselage, particularly in aircraft using BLC. The proposed technique foresees the use of elastic surfaces on which insect roughness cannot form. The operational characteristics of highly elastic rubber surface fastened to the wing leading edges and fuselage edges are examined. Some preliminary test results are presented. The technique is seen to be advantageous primarily for short-haul operations
Stout Whiting Fishery Summary : Commercial Quota Setting for 2017
This fishery assessment report describes the commercial stout whiting fishery operation along Australia’s east coast between Sandy Cape and the Queensland-New South Wales border. The fishery is identified by a T4 symbol.
This study follows methods applied in (O'Neill & Leigh, 2016a) and extends the results of that study by using the latest data available up to end of March 2016. The fishery statistics reported herein are for fishing years 1991 to 2016.
This study analysed stout whiting catch rates from both Queensland and New South Wales (NSW) for all vessels, areas and fishing gears. The 2016 catch rate index from Queensland and NSW waters was 0.86. This means that the 2016 catch rate index was 86% of the mean standardised catch rate. Results showed that there was a stable trend in catch rates from 2012 to 2016, as in the previous study (O'Neill & Leigh, 2016a), with the 2015 and 2014 catch rates 85% of the mean catch rate.
The fish-length frequency and age-length-otolith data were translated using two models which showed:
• Where patterns of fish age-abundance were estimated from the fish-length frequency and age-length data, there were slightly decreased estimated measures of fish survival at 38% for 2014, compared to fish survival estimates in 2013 at 40%. The 2014 and 2015 estimated age structure was dominated by 1+ and 2+ old fished, with a slightly higher frequency of age 2 - 3 fish for 2015.
• Where only the age-length data were used, estimates showed that from 2011 to 2014 the survival index increased. The estimated survival index increased from 35% in 2013 to 64% in 2014, indicating stronger survival of fish as they recruited and aged.
Together the stout whiting catch rate and survival indicators showed the recent fishery harvests were sustainable.
Since 1997, T4 management (Stout Whiting Fishery) is centred on annual assessments of total allowable commercial catch (TACC). The TACC is assessed before the start of each fishing year using statistical assessment methodologies, namely evaluation of trends in fish catch rates and catch-at-age frequencies measured against management reference points. The TACC has been under-caught in many years.
For setting the 2017 T4 stout whiting TACC, the calculations covered a range of settings to account for the variance in the data and provide options for quota change. The overall (averaged) results suggested:
• The procedure where the quota was adjusted based on previous TACC setting in year 2016 gave a recommended TACC for 2017 of between 1100 and 1130 t.
• The procedure that focussed directly on optimising the average harvest to match target reference points gave a recommended TACC for 2017 of between 860 and 890 t.
Use of these estimates to set TACC will depend on management and industry aims for the fishery
Accomplishments of participatory research for systems improvement in Iganga District, Uganda 1993 to 1997
Stock Assessment of Ballot's saucer scallop (Ylistrum balloti) in Queensland
This assessment estimates the status of saucer scallops in the main fishing grounds of the Queensland Southern Inshore fishery. The stock assessment data inputs included total harvests, standardised catch rates and fishery independent density estimates.
Analyses suggested that spawning biomass in 2019 fell to around 17 per cent of the unfished level. The report presents recommendations on fishing effort levels to begin rebuilding the stock to levels consistent with 40 per cent of unfished biomass
Maximally Localized Wannier Functions within the FLAPW formalism
We report on the implementation of the Wannier Functions (WFs) formalism
within the full-potential linearized augmented plane wave method (FLAPW),
suitable for bulk, film and one-dimensional geometries. The details of the
implementation, as well as results for the metallic SrVO3, ferroelectric BaTiO3
grown on SrTiO3, covalently bonded graphene and a one-dimensional Pt-chain are
given. We discuss the effect of spin-orbit coupling on the Wannier Functions
for the cases of SrVO3 and platinum. The dependency of the WFs on the choice of
the localized trial orbitals as well as the difference between the maximally
localized and "first-guess" WFs are discussed. Our results on SrVO3 and BaTiO3,
e.g. the ferroelectric polarization of BaTiO3, are compared to results
published elsewhere and found to be in excellent agreement.Comment: 13 pages, 9 figures, accepted for publication in Phys. Rev.
Quantification of ductal blood flow with magnetic resonance imaging in newborns with obstructive left heart disease
Quantitative assessment of the Queensland saucer scallop (Amusium balloti) fishery
In recent years (2015 and 2016) there has been growing concern from members of the fishing industry and the Queensland Government over declining catches of legal-sized saucer scallop. This led to a request in mid-2016 by Fisheries Queensland, the fisheries management service within the Department of Agriculture and Fisheries, for an investigative analysis of the status of saucer scallops.
The scope of the investigation was limited to a short time frame of three months to urgently analyse the most recent data and undertake a stock assessment. This report provides findings that support the concerns about low abundance of legal-sized scallops.
Average catch rates from January 2015 to April 2016 were the lowest in the 39-year record. These recent average catch rates are slightly lower than those in 1996 when the scallop population size fell to low levels and emergency closed areas were implemented by the Government. From these data the model estimates of spawning stock in 2015 are potentially as low as 5-6% of 1977 levels, when the fishery was in its early development
Spontaneous virologic suppression in HIV controllers is independent of delayed-type hypersensitivity test responsiveness
<p>Abstract</p> <p>Background</p> <p>Delayed-type hypersensitivity (DTH) testing, an in vivo assessment of cell-mediated immunity, is a predictor of HIV disease progression beyond CD4 cell count. We investigated whether preserved DTH responsiveness was characteristic of HIV controllers compared to non-controllers and individuals on suppressive HAART.</p> <p>Findings</p> <p>DTH testing consisted of ≥ 3 recall antigens applied approximately every 6 months. DTH responses were classified by the number of positive skin tests: anergic (0), partial anergic (1), or non-anergic (≥ 2). HIV controllers were compared to treatment naïve non-controllers (n = 3822) and a subgroup of non-controllers with VL < 400 copies/mL on their initial HAART regimen (n = 491). The proportion of non-anergic results at first DTH testing was similar for HIV controllers compared to non-controllers (81.9% vs. 77.6%; P = 0.22), but tended to be greater in HIV controllers compared to the HAART subgroup (81.9% vs. 74.5%; P = 0.07). Complete anergy was observed in 14 (10.1%) HIV controllers with CD4 counts ≥ 400 cells/uL. For longitudinal testing, the average percentage of non-anergic DTH determinations per participant was higher in HIV controllers compared to non-controllers (81.2 ± 31.9% vs. 70.7 ± 36.8%; P = 0.0002), however this difference was eliminated with stratification by CD4 count: 200-399 (83.4 ± 35.6% vs. 71.9 ± 40.9%; P = 0.15) and > 400 cells/uL (81.2 ± 31.5% vs. 80.4 ± 32.7%; P = 0.76).</p> <p>Conclusions</p> <p>Spontaneous virologic control was not associated with DTH responsiveness, and several HIV controllers were anergic despite having elevated CD4 counts. These findings suggest that cellular immunity assessed by DTH is not a principal factor contributing to spontaneous virologic suppression in HIV controllers.</p
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