Black flies (Diptera : Simuliidae) of the Marquesas Islands, French Polynesia : redescriptions and new species

On trouvera ici une nouvelle description de tous les stades de #Simulium buissoni Roubaud, 1906. Des larves, nymphes et mâles de #S. gallinum Edwards, 1932 ont été associés à l'holotype femelle et on peut en lire ici la description. Il en va de même pour #S. adamsoni Edwards, 1932 dont les mâles, aux cerques renflés et aux gonocoxas fusionnées en leur milieu, possèdent une grande plaque ventrale carénée. L'holotype femelle et deux paratypes de #S. mumfordi Edwards, 1932 font l'objet de descriptions entièrement nouvelles. Des mâles et des femelles de #S. kukaense Séchan, 1983 ont été associés aux nymphes et aux larves et ils sont décrits ici; tout le matériel type de cette espèce a été perdu et il a donc fallu désigner un néotype. #Simulium uaense Séchan, 1983 est mentionné. Trois nouvelles espèces sont décrites : #S. pichoni Craig, Fossati et Séchan, #S. rivierei Craig, Fossati et Séchan et #S. sechani$ Craig et Fossati. La dynamique des populations et les relations interspécifiques font l'objet de brefs commentaires. (Résumé d'auteur

An Algorithm for constructing Hjelmslev planes

Projective Hjelmslev planes and Affine Hjelmselv planes are generalisations of projective planes and affine planes. We present an algorithm for constructing a projective Hjelmslev planes and affine Hjelsmelv planes using projective planes, affine planes and orthogonal arrays. We show that all 2-uniform projective Hjelmslev planes, and all 2-uniform affine Hjelsmelv planes can be constructed in this way. As a corollary it is shown that all 2-uniform Affine Hjelmselv planes are sub-geometries of 2-uniform projective Hjelmselv planes.Comment: 15 pages. Algebraic Design Theory and Hadamard matrices, 2014, Springer Proceedings in Mathematics & Statistics 13

Towards large scale microwave treatment of ores: Part 1 – Basis of design, construction and commissioning

Despite over thirty years of work, microwave pre-treatment processes for beneficiation of ores have not progressed much further than laboratory testing. In this paper we present a scaleable pilot-scale system for the microwave treatment of ores capable of operating at throughputs of up to 150tph. This has been achieved by confining the electric field produced from two 100kW generators operating at 896MHz in a gravity fed vertical flow system using circular choking structures yielding power densities of at least 6x108 W/m3 in the heated mineral phases. Measured S11 scattering parameters for a quartzite ore (-3.69±0.4dB) in the as-built applicator correlated well with the simulation (-3.25dB), thereby validating our design approach. We then show that by fully integrating the applicator with a materials handling system based on the concept of mass flow, we achieve a reliable, continuous process. The system was used to treat a range of porphyry copper ores

The relationship between fetal growth and retinal nerve fiber layer thickness in a cohort of young adults

Purpose: To explore relationships between patterns of fetal anthropometric growth, as reflective of fetal wellbeing, and global retinal nerve fiber layer (RNFL) thickness measured in young adulthood. Methods: Participants (n = 481) from within a Western Australian pregnancy cohort study underwent five serial ultrasound scans during gestation, with fetal biometry measured at each scan. Optic disc parameters were measured via spectral-domain optical coherence tomography imaging at a 20-year follow-up eye examination. Generalized estimating equations were used to evaluate differences in global RNFL thickness between groups of participants who had undergone similar growth trajectories based on fetal head circumference (FHC), abdominal circumference (FAC), femur length (FFL), and estimated fetal weight (EFW). Results: Participants with consistently large FHCs throughout gestation had significantly thicker global RNFLs than those with any other pattern of FHC growth (P = 0.023), even after adjustment for potential confounders (P = 0.037). Based on model fit statistics, FHC growth trajectory was a better predictor of global RNFL thickness than birth weight or head circumference at birth. RNFL thickness did not vary significantly between groups of participants with different growth trajectories based on FAC, FFL, or EFW. Conclusions: FHC growth is associated with RNFL thickness in young adulthood and, moreover, is a better predictor than either birth weight or head circumference at birth. Translational Relevance: This research demonstrates an association between intrauterine growth and long-term optic nerve health, providing a basis for further exploring the extent of the influence of fetal wellbeing on clinical conditions linked to RNFL thinning

Field-tunable magnetic phases in a semiconductor-based two-dimensional Kondo lattice

We show the existence of intrinsic localized spins in mesoscopic high-mobility GaAs/AlGaAs heterostructures. Non-equilibrium transport spectroscopy reveals a quasi-regular distribution of the spins, and indicates that the spins interact indirectly via the conduction electrons. The interaction between spins manifests in characteristic zero-bias anomaly near the Fermi energy, and indicates gate voltage-controllable magnetic phases in high-mobility heterostructures. To address this issue further, we have also designed electrostatically tunable Hall devices, that allow a probing of Hall characteristics at the active region of the mesoscopic devices. We show that the zero field Hall coefficient has an anomalous contribution, which can be attributed to scattering by the localized spins. The anomalous contribution can be destroyed by an increase in temperature, source drain bias, or field range.Comment: To be published in PhysicaE EP2DS proceedin

Disturbance propagation through a grinding-flotation circuit

The propagation of common disturbances in a grinding circuit connected to a flotation circuit and the effects of these disturbances on flotation cell levels were simulated and analysed. The disturbances include changes in the mineral ore feed as well as a step change in the cyclone operating condition and spillage water added to the sump. The effect of the disturbances on the cell levels remains relatively small, but it is clear that multivariable control is required to prevent the propagation of the disturbances through the cells. The simulation of a grinding-flotation circuit is useful to simulate the effects of disturbance propagation and will be helpful when designing plant-wide controllers.This work is based on research supported by the National Research Foundation of South Africa (Grant number 130380).https://www.journals.elsevier.com/ifac-papersonlineam2022Electrical, Electronic and Computer Engineerin

Extremism seeking control of a flotation circuit using peak air recovery

A flotation circuit is simulated with an extremum seeking controller to keep the cells operating at the optimal operating point represented by peak air recovery. It is assumed that at this operating point, the froth layer is stabilised and the mineral recovery of the flotation cell is maximised resulting in optimal performance. The extremum seeking controller uses periodic perturbations in the aeration rate to steer the system through an unknown static map towards the peak in air recovery. The controller is able to find the peak air recovery operating point and track the point as it changes in the presence of external disturbances. The extremum seeking controller is ideally suited for model-independent long-term automated optimisation of a flotation circuit with a time-varying optimal operating point.https://www.journals.elsevier.com/ifac-papersonlineElectrical, Electronic and Computer Engineerin

The Seasonal Flux and Fate of Dissolved Organic Carbon Through Bacterioplankton in the Western North Atlantic

The oceans teem with heterotrophic bacterioplankton that play an appreciable role in the uptake of dissolved organic carbon (DOC) derived from phytoplankton net primary production (NPP). As such, bacterioplankton carbon demand (BCD), or gross heterotrophic production, represents a major carbon pathway that influences the seasonal accumulation of DOC in the surface ocean and, subsequently, the potential vertical or horizontal export of seasonally accumulated DOC. Here, we examine the contributions of bacterioplankton and DOM to ecological and biogeochemical carbon flow pathways, including those of the microbial loop and the biological carbon pump, in the Western North Atlantic Ocean (∼39–54°N along ∼40°W) over a composite annual phytoplankton bloom cycle. Combining field observations with data collected from corresponding DOC remineralization experiments, we estimate the efficiency at which bacterioplankton utilize DOC, demonstrate seasonality in the fraction of NPP that supports BCD, and provide evidence for shifts in the bioavailability and persistence of the seasonally accumulated DOC. Our results indicate that while the portion of DOC flux through bacterioplankton relative to NPP increased as seasons transitioned from high to low productivity, there was a fraction of the DOM production that accumulated and persisted. This persistent DOM is potentially an important pool of organic carbon available for export to the deep ocean via convective mixing, thus representing an important export term of the biological carbon pump

On the thermal sunset diagram for scalar field theories

We study the so-called `` sunset diagram'', which is one of two-loop self-energy diagrams, for scalar field theories at finite temperature. For this purpose, we first find the complete expression of the bubble diagram, the one-loop subdiagram of the sunset diagram, for arbitrary momentum. We calculate the temperature independent part and dependent part of the sunset diagram separately. For the former, we obtain the discontinuous part first and the finite continuous part next using a twice-subtracted dispersion relation. For the latter, we express it as a one-dimensional integral in terms of the bubble diagram. We also study the structure of the discontinuous part of the sunset diagram. Physical processes, which are responsible for it, are identified. Processes due to the scattering with particles in the heat bath exist only at finite temperature and generate discontinuity for arbitrary momentum, which is a remarkable feature of the two-loop diagrams at finite temperature. As an application of our result, we study the effect of the diagram on the spectral function of the sigma meson at finite temperature in the linear sigma model, which was obtained at one-loop order previously. At high temperature where the decay $\sigma\to\pi\pi$ is forbidden, sigma acquires a finite width of the order of $10 {\rm MeV}$ while within the one-loop calculation its width vanishes. At low temperature, the spectrum does not deviate much from that at one-loop order. Possible consequences with including other two-loop diagrams are discussed.Comment: 30 page