Application of satellite precipitation data to analyse and model arbovirus activity in the tropics

Background: Murray Valley encephalitis virus (MVEV) is a mosquito-borne Flavivirus (Flaviviridae: Flavivirus) which isclosely related to Japanese encephalitis virus, West Nile virus and St. Louis encephalitis virus. MVEV is enzootic innorthern Australia and Papua New Guinea and epizootic in other parts of Australia. Activity of MVEV in WesternAustralia (WA) is monitored by detection of seroconversions in flocks of sentinel chickens at selected sample sitesthroughout WA.Rainfall is a major environmental factor influencing MVEV activity. Utilising data on rainfall and seroconversions,statistical relationships between MVEV occurrence and rainfall can be determined. These relationships can be usedto predict MVEV activity which, in turn, provides the general public with important information about diseasetransmission risk. Since ground measurements of rainfall are sparse and irregularly distributed, especially in northWA where rainfall is spatially and temporally highly variable, alternative data sources such as remote sensing (RS)data represent an attractive alternative to ground measurements. However, a number of competing alternatives areavailable and careful evaluation is essential to determine the most appropriate product for a given problem.Results: The Tropical Rainfall Measurement Mission (TRMM) Multi-satellite Precipitation Analysis (TMPA) 3B42product was chosen from a range of RS rainfall products to develop rainfall-based predictor variables and buildlogistic regression models for the prediction of MVEV activity in the Kimberley and Pilbara regions of WA. Twomodels employing monthly time-lagged rainfall variables showed the strongest discriminatory ability of 0.74 and0.80 as measured by the Receiver Operating Characteristics area under the curve (ROC AUC).Conclusions: TMPA data provide a state-of-the-art data source for the development of rainfall-based predictivemodels for Flavivirus activity in tropical WA. Compared to ground measurements these data have the advantage ofbeing collected spatially regularly, irrespective of remoteness. We found that increases in monthly rainfall andmonthly number of days above average rainfall increased the risk of MVEV activity in the Pilbara at a time-lag oftwo months. Increases in monthly rainfall and monthly number of days above average rainfall increased the risk ofMVEV activity in the Kimberley at a lag of three months.I

Comparison of Disturbance Impacts to and Spatial Distribution of Biological Soil Crusts in the Little San Bernardino Mountains of Joshua Tree National Park, California

Biological soil crust ecology in the hot Mojave Desert is poorly understood with regard to crust distribution and abundance, as well as the impacts of trampling disturbance on crust development. Our objective was to study biological soil crusts in 2 areas of differing disturbance pressures in the high desert region of Joshua Tree National Park, California, with respect to visible crust cover and frequency, chlorophyll a, and soil stability. Impacts on biological soil crusts from 2 disturbance regimes, historic grazing and recent high knot traffic, were compared using a disturbance indicator. In addition, we measured a suite of abiotic and biotic soil parameters commonly associated with crust abundance and distribution and characterized occurrence with respect to 3 geomorphic features (pockets, slopes, and wash banks). Individual physical and chemical soil parameters historically have been associated with crust development. In contrast, this study demonstrates that geomorphic features with a suite of soil properties clearly impacted crust development. In both study areas, wash banks showed the best crust development (51.%-52% total crust cover) and slopes showed the poorest crust development (\u3c37% total crust cover). Lichens and mosses were best developed in the pocket areas (1.1% and 1.5% cover, 25%-30% frequency), which can accumulate and retain moisture during and following precipitation events. Our disturbance index suggested that the high-foot-traffic area, being associated with a reduction in visible crust cover, hiss experienced inure recent disturbance than the historically grazed sites. However, despite the reduction in cover, the high-foot-traffic area had more lichen and moss crusts, indicating that the crusts in this area are more successionally mature. In contrast, the historically grazed area showed clear signs of recovery from past grazing disturbance, with a higher visual cover of biological soil crusts. However, crusts also had lower biomass values, supporting an earlier successional stage. Overall, we conclude that biological soil crusts of the Mojave Desert are very different in composition, form, and ecology than crusts of other desert regions of North America

Assessing Evolutionary Significant Units (ESU) of the Endangered Freshwater Pearl Mussel (Margaritifera margaritifera) in Southeast Norway on the Basis of Genetic Analysis

A total of 312 specimens of freshwater pearl mussel (Margaritifera margaritifera) were sampled from 11 populations, located in four different river systems in Southeast Norway, and analyzed for 11 simple sequence repeat (SSR) (microsatellite) markers. All study populations have landlocked brown trout (Salmo trutta) as the only possible host. Several populations had experienced recruitment failure, probably due to low pH (about 6.0) and calcium concentration. STRUCTURE clustering analysis revealed two genetic clusters, of which one cluster occurred mainly in the western river systems, and totally dominated in one population (Fallselva (A-FAL)) that had higher genetic diversity than the others. Cluster 2 completely dominated in the populations of the eastern river systems, and all of them had low genetic diversity. Bottleneck events were indicated in all populations and the inbreeding coefficient FIS was significant in all populations, except for the southernmost population (Sørkedalselva (B-SØR)), which was the only population with genotypes in Hardy–Weinberg equilibrium. FIS were especially high in the populations of the eastern river systems, and maximum shell length was negatively correlated to FIS. If artificially breeding and stocking should become necessary for future preservation, it should be based on single populations; alternatively, the eastern populations should be based on cross-breeding of populations within the cluster to increase their genetic diversity.publishedVersio

OH PLIF Visualization of a Premixed Ethylene-fueled Dual-Mode Scramjet Combustor

Hydroxyl radical (OH) planar induced laser fluorescence (PLIF) measurements have been performed in a small-scale scramjet combustor at the University of Virginia Aerospace Research Laboratory at nominal simulated Mach 5 enthalpy. OH lines were carefully chosen to have fluorescent signal that is independent of pressure and temperature but linear with mole fraction. The OH PLIF signal was imaged in planes orthogonal to and parallel to the freestream flow at different equivalence ratios. Flameout limits were tested and identified. Instantaneous planar images were recorded and analyzed to compare the results with width increased dual-pump enhanced coherent anti-Stokes Raman spectroscopy (WIDECARS) measurements in the same facility and large eddy simulation/Reynolds average Navier-Stokes (LES/RANS) numerical simulation. The flame angle was found to be approximately 10 degrees for several different conditions, which is in agreement with numerical predictions and measurements using WIDECARS. Finally, a comparison between NO PLIF non-combustion cases and OH PLIF combustion cases is provided: the comparison reveals that the dominant effect of flame propagation is freestream turbulence rather than heat release and concentration gradients

OH PLIF Visualization of the UVa Supersonic Combustion Experiment: Configuration A

Hydroxyl radical (OH) planar laser-induced fluorescence (PLIF) measurements were performed in the University of Virginia s dual-mode scramjet experiment. The test section was set up in configuration A, which includes a Mach 2 nozzle, combustor, and extender section. Hydrogen fuel was injected through an unswept compression ramp at two different equivalence ratios. Through the translation of the optical system and the use of two separate camera views, the entire optical range of the combustor was accessed. Single-shot, average, and standard deviation images of the OH PLIF signal are presented at several streamwise locations. The results show the development of a highly turbulent flame structure and provide an experimental database to be used for numerical model assessment

OH PLIF Visualization of the UVa Supersonic Combustion Experiment: Configuration C

Non-intrusive hydroxyl radical (OH) planar laser-induced fluorescence (PLIF) measurements were obtained in configuration C of the University of Virginia supersonic combustion experiment. The combustion of hydrogen fuel injected through an unswept compression ramp into a supersonic cross-flow was imaged over a range of streamwise positions. Images were corrected for optical distortion, variations in the laser sheet profile, and different camera views. Results indicate an effect of fuel equivalence ratio on combustion zone shape and local turbulence length scale. The streamwise location of the reaction zone relative to the fuel injector was also found to be sensitive to the fuel equivalence ratio. The flow boundary conditions in the combustor section, which are sensitive to the fuel flow rate, are believed to have caused this effect. A combination of laser absorption and radiative trapping effects are proposed to have caused asymmetry observed in the images. The results complement previously published OH PLIF data obtained for configuration A along with other non-intrusive measurements to form a database for computational fluid dynamics (CFD) model validation

Functional SARS-CoV-2 cross-reactive CD4+ T cells established in early childhood decline with age.

Pre-existing SARS-CoV-2-reactive T cells have been identified in SARS-CoV-2-unexposed individuals, potentially modulating COVID-19 and vaccination outcomes. Here, we provide evidence that functional cross-reactive memory CD4+ T cell immunity against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is established in early childhood, mirroring early seroconversion with seasonal human coronavirus OC43. Humoral and cellular immune responses against OC43 and SARS-CoV-2 were assessed in SARS-CoV-2-unexposed children (paired samples at age two and six) and adults (age 26 to 83). Pre-existing SARS-CoV-2-reactive CD4+ T cell responses targeting spike, nucleocapsid, and membrane were closely linked to the frequency of OC43-specific memory CD4+ T cells in childhood. The functional quality of the cross-reactive memory CD4+ T cell responses targeting SARS-CoV-2 spike, but not nucleocapsid, paralleled OC43-specific T cell responses. OC43-specific antibodies were prevalent already at age two. However, they did not increase further with age, contrasting with the antibody magnitudes against HKU1 (β-coronavirus), 229E and NL63 (α-coronaviruses), rhinovirus, Epstein-Barr virus (EBV), and influenza virus, which increased after age two. The quality of the memory CD4+ T cell responses peaked at age six and subsequently declined with age, with diminished expression of interferon (IFN)-γ, interleukin (IL)-2, tumor necrosis factor (TNF), and CD38 in late adulthood. Age-dependent qualitative differences in the pre-existing SARS-CoV-2-reactive T cell responses may reflect the ability of the host to control coronavirus infections and respond to vaccination