Environmental risk factors associated with the presence of Mycobacterium ulcerans in Victoria, Australia

In recent years reported cases of Buruli ulcer (BU), caused by Mycobacterium ulcerans (MU), have increased substantially in Victoria, Australia, with the epidemic also expanding geographically. To develop an understanding of how MU circulates in the environment and transmits to humans we analyzed environmental samples collected from 115 properties of recent BU cases and from 115 postcode-matched control properties, for the presence of MU. Environmental factors associated with increased odds of MU presence at a property included certain native plant species and native vegetation in general, more alkaline soil, lower altitude, the presence of common ringtail possums (Pseudocheirus peregrinus) and overhead powerlines. However, only powerlines and the absence of the native plant Melaleuca lanceolata were associated with BU case properties. Samples positive for MU were more likely to be found at case properties and were associated with detections of MU in ringtail possum feces, supporting the hypothesis that MU is zoonotic, with ringtail possums the strongest reservoir host candidate. However, the disparity in environmental risk factors associated with MU positive properties versus case properties indicates a strong human behavioral component or the influence of other environmental factors in disease acquisition that requires further study.

Oribatid mites (Acari, Oribatida) from “Parco Naturale delle Alpi Marittime” (Piedmont, Italy)

Oribatid mites were investigated in six sites in the Alpi Marittime Natural Park (Prov. Cuneo, Piedmont, northern Italy) which is part of the NATURA 2000 network. The selected locations cover 4 forested (fir, ash, 2 beech forests) and 2 grassland sites (mountain meadow, xeric grassland). Altogether 173 described oribatid species belonging to 51 families were encountered, complemented by one undetermined species (Scheloribates (Topobates) cf. carpathicus), added together 174 species. Among them 11 species are new records for Italy. A comparison with other Italian alpine provinces shows high similarity of the oribatid species composition from the investigated sites with the provinces of Bolzano, Trento, Sondrio. A total of 37 species from the Marittime Alps has also been recorded in the southern part of the nearby Swiss canton Ticino. The majority of the species in the investigated sites are known as silvicolous; xerophilous species were mainly found in the xeric grassland site at lower altitude. High species similarities are observed between the forested sites, which also show high species numbers (up to 96 spp. found in the fir forest), lowest similarities are found between the open grassland sites and the forested sites, as well as between the grassland sites themselves.

Configuration of the Volatile Aromatic Profile of Carob Powder Milled From Pods of Genetic Variants Harvested at Progressive Stages of Ripening From High and Low Altitudes

Carob powder is increasingly valued as a substitute for cocoa and as a flavor-enhancing component of processed foods. However, little is known about the impact of preharvest factors such as fruit maturity, genotype and altitude on its volatile organic compounds (VOCs) composition. The current study examined the VOCs composition of powder milled from pods of two genotypes cultivated at 15 and 510 m altitude and harvested at six progressive stages of maturity, ranging from fully developed immature green (RS1) to late ripe (RS6). Fifty-six VOCs categorized into acids, esters, aldehydes, ketones, alcohols, furans, and alkanes were identified through HS-SPME GC-MS analysis. Maturity was the most influential factor, followed by altitude and least by genotype. Aldehydes and alcohols correlated positively (r = 0.789; p < 0.001), both accumulated in immature carobs and decreased with progressive ripening, resulting in the attenuation of green grassy aroma. Conversely, acids increased with ripening and dominated the carob volatilome at full maturity, correlating negatively with aldehydes and alcohols (r = −0.835 and r = −0.950, respectively; p < 0.001). The most abundant VOC throughout ripening (17.3-57.7%) was isobutyric acid, responsible for the characteristic cheesy-acidic-buttery aroma of carob powder. The pleasurable aroma detected at the immature stages (RS2 and RS3) was traced to isobutyrate and methyl isobutyrate esters, rendering unripe green carob powder a potential admixture component for improving the aroma of novel food products. Lower altitude favored the accumulation of acids linked to less pleasant aroma, whereas isobutyric acid was more abundant at higher altitude. This constitutes a significant indication that higher altitude enhances the characteristic carob-like aroma and sensory quality of carob powder.

Analyses of Wheat Yellow Rust Populations Reveal Sexual Recombination and Seasonal Migration Pattern of Puccinia striiformis f. sp. tritici in Gangu, Northwestern China

Puccinia striiformis f. sp. tritici is the causal agent of wheat yellow rust with records of regular and severe epidemics in China. This study explored the population dynamics of the yellow rust pathogen in Gangu, northwestern China. In Gangu, the Weihe River runs from west to east and divides Gangu into three regions: North and South mountain, with the valley in between. To study the genetic structure of the pathogen in local populations, samples were collected over 3 years from the three regions at different altitudes both within and between the wheat cropping seasons. A total of 811 P. striiformis f. sp. tritici isolates were successfully genotyped using 16 simple sequence repeat markers. The results suggest that P. striiformis f. sp. tritici can survive year-round in Gangu. The P. striiformis f. sp. tritici populations migrated among the regions, and the migration pattern was not related to altitude. The oversummering populations in the North and South mountain regions were genetically different from each other; and the P. striiformis f. sp. tritici populations collected from the lower altitude in the valley had no relationship with any of the populations collected in the spring or fall, indicating that they too have a different origin. Signatures of random mating were found in the populations collected in both North and South mountain regions, but not in the valley populations.

Synoptic processes of winter precipitation in the Upper Indus Basin

Precipitation in the Upper Indus Basin is triggered by orographic interaction and the forced uplift of a cross-barrier moisture flow. Winter precipitation events are particularly active in this region and are driven by an approaching upper-troposphere western disturbance. Here statistical tools are used to decompose the winter precipitation time series into a wind and a moisture contribution. The relationship between each contribution and the western disturbances are investigated. We find that the wind contribution is related not only to the intensity of the upper-troposphere disturbances but also to their thermal structure through baroclinic processes. Particularly, a short-lived baroclinic interaction between the western disturbance and the lower-altitude cross-barrier flow occurs due to the shape of the relief. This interaction explains both the high activity of western disturbances in the area and their quick decay as they move further east. We also revealed the existence of a moisture pathway from the Red Sea to the Persian Gulf and the north of the Arabian Sea. A western disturbance strengthens this flow and steers it towards the Upper Indus Plain, particularly if it originates from a more southern latitude. In cases where the disturbance originates from the north-west, its impact on the moisture flow is limited, since the advected continental dry air drastically limits the precipitation output. The study offers a conceptual framework to study the synoptic activity of western disturbances as well as key parameters that explain their precipitation output. This can be used to investigate meso-scale processes or intra-seasonal to inter-annual synoptic activity.

Leaf Vein Morphological Variation in Four Endangered Neotropical Magnolia Species along an Elevation Gradient in the Mexican Tropical Montane Cloud Forests

Climatic variations influence the adaptive capacity of trees within tropical montane cloud forests species. Phenology studies have dominated current studies on tree species. Leaf vein morphology has been related to specific climatic oscillations and varies within species along altitudinal gradients. We tested that certain Neotropical broad leaf Magnolia species might be more vulnerable to leaf vein adaptation to moisture than others, as they would be more resilient to the hydric deficit. We assessed that leaf vein trait variations (vein density, primary vein size, vein length, and leaf base angle) among four Magnolia species (Magnolia nuevoleonensis, M. alejandrae, M. rzedowskiana, and Magnolia vovidesii) through the Mexican Tropical montane cloud forest with different elevation gradient and specific climatic factors. The temperature, precipitation, and potential evaporation differed significantly among Magnolia species. We detected that M. rzedowskiana and M. vovidesii with longer leaves at higher altitude sites are adapted to higher humidity conditions, and that M. nuevoleonensis and M. alejandrae inhabiting lower altitude sites are better adjusted to the hydric deficit. Our results advance efforts to identify the Magnolia species most vulnerable to climate change effects, which must focus priorities for conservation of this ecosystem, particularly in the Mexican tropical montane cloud forests.

Spatial and Temporal Variations of Climate on Different Flanks and Elevations in the Qinling-Daba Mountains of China from 1969 to 2018

Climate change presents great variations on different flanks and elevations in the same mountain range. Analysis of the spatial and temporal variations of climate on different flanks and elevations in the north-south transition zone--the Qinling-Daba Mountains (QDM) are of great significance for exploring the complexity of climate geography pattern and phenology in China. This paper collected 118 weather stations data on daily temperature and precipitation during 1969-2018 from the National Meteorological Information Center, and then explored the temporal and spatial distribution characteristics of climate on different flanks and elevations. The results showed that: 1) On the whole, there was a significant warming trend in the four seasons in the past 50 years. Precipitation did not show significant variation at most stations with an exception to 8 weather stations having significant changes in trend in different seasons. 2) The temperature showed an increasing trend in different seasons, but its increasing rate varied greatly on different flanks. Generally speaking, climate change was greater on the northern flanks than that on the southern flanks in the four seasons in the QDM. Temperature tendency is greater in spring and winter than in summer and autumn on different flanks in the QDM. 3) The increase rate of temperature varied greatly at different elevations in different seasons. The warming rate was greater in the higher altitude regions than that of the lower altitude regions in summer, autumn and winter, while, in spring, however, it is higher in the lower altitudes than in the higher altitudes.

Urbanization and altitude impact on gut microbiome of an Andean frog (Pristimantis unistrigatus)

The analysis of the intestinal microbiome in amphibians provides insights of the anthropogenic environmental impact. Pristimantis unistrigatus is an Andean amphibian species whose distribution has been recorded in Ecuador and Colombia, ranging from endemic elfin forests to urban gardens. In this study, we focus on the analysis of the P. unistrigatus microbiome 16S rRNA gene sequencing. A total of 32 specimens of P. unistrigatus were collected and analyzed from 4 locations in the Valley of Quito, Ecuador, characterized by several urban environments and altitudes. The results show that the relative abundance of bacteria is significantly different amongst groups. Clostridiales are proportionally more abundant in rural and lower altitude locations, while Erysipelotrichaceae, Desulfovibrionaceae, Enterobacteriaceae, Bacteroidaceae and Lachnospiraceae are found at higher elevations. These results highlight the importance of the evolution of the microbiome as a tool of adaptation and survival of amphibians in the present-day changing ecosystems undergoing anthropogenic stresses.

Two-Stage Channel Adaptive Algorithm for Unmanned Aerial Vehicles Localization with Cellular Networks

Unmanned aerial vehicle (UAV) is regarded as a powerful tool to expand the existing ground wireless network into aerial space. Since high mobility is an essential characteristic for UAV, it is important to carry out an accurate, real-time, and high-precision localization in terms of safe operation and communication link maintenance. The cellular network-based localization technology has provided UAV a solution with both high coverage and seamless connection. However, the complex channel environment between the UAV and terrestrial base station (BS) would have weakened the localization performance. To solve this problem, a two-stage channel adaptive algorithm for cellular-connected UAV has been proposed. The first stage of the algorithm is to revise the observation error introduced by the complex channel environment using the model of DDPG. The second stage is to locate the UAV position with TDOA algorithm using the revised observation values. Simulation results have demonstrated that the proposed algorithm can achieve the channel adaptive effect by revising the observation errors and improve location performance greatly, especially for UAVs at a relative lower altitude.

Defining hypoxaemia from pulse oximeter measurements of oxygen saturation in well children at low altitude in Bangladesh: an observational study

BackgroundWHO defines hypoxaemia, a low peripheral arterial oxyhaemoglobin saturation (SpO2), as <90%. Although hypoxaemia is an important risk factor for mortality of children with respiratory infections, the optimal SpO2 threshold for defining hypoxaemia is uncertain in low-income and middle-income countries (LMICs). We derived a SpO2 threshold for hypoxaemia from well children in Bangladesh residing at low altitude.MethodsWe prospectively enrolled well, children aged 3–35 months participating in a pneumococcal vaccine evaluation in Sylhet district, Bangladesh between June and August 2017. Trained health workers conducting community surveillance measured the SpO2 of children using a Masimo Rad-5 pulse oximeter with a wrap sensor. We used standard summary statistics to evaluate the SpO2 distribution, including whether the distribution differed by age or sex. We considered the 2.5th, 5th and 10th percentiles of SpO2 as possible lower thresholds for hypoxaemia.ResultsOur primary analytical sample included 1470 children (mean age 18.6±9.5 months). Median SpO2 was 98% (IQR 96%–99%), and the 2.5th, 5th and 10th percentile SpO2 was 91%, 92% and 94%. No child had a SpO2 <90%. Children 3–11 months had a lower median SpO2 (97%) than 12–23 months (98%) and 24–35 months (98%) (p=0.039). The SpO2 distribution did not differ by sex (p=0.959).ConclusionA SpO2 threshold for hypoxaemia derived from the 2.5th, 5th or 10th percentile of well children is higher than <90%. If a higher threshold than <90% is adopted into LMIC care algorithms then decision-making using SpO2 must also consider the child’s clinical status to minimise misclassification of well children as hypoxaemic. Younger children in lower altitude LMICs may require a different threshold for hypoxaemia than older children. Evaluating the mortality risk of sick children using higher SpO2 thresholds for hypoxaemia is a key next step.