The COVID-19 pandemic: prediction study based on machine learning models

Environmental Science and Pollution Research - COVID-19 was first discovered in Wuhan, China in December 2019. It is one of the worst pandemics in human history. Recent studies reported that...     

Magnetic photocatalysts from δ-FeOOH and TiO2 and application in reactions for degradation of methylene blue and paracetamol with UV-C and sunlight

Environmental Science and Pollution Research - Water contamination is a common problem, especially considering dyes and drugs disposal. A possible and effective treatment method to remove these...     

Lung-deposited dose of particulate matter from residential exposure to smoke from wood burning

Environmental Science and Pollution Research - Residential settings are of utmost importance for human exposure, as it is where people spend most of their time. Residential wood combustion is a...     

Structure and activity of thermophilic methanogenic microbial communities exposed to quaternary ammonium sanitizer

Food processing facilities often use antimicrobial quaternary ammonium compound (QAC) sanitizers to maintain cleanliness. These QACs can end up in wastewaters used as feedstock for anaerobic digestion. The aim of this study was to measure the effect of QAC contamination on biogas production and structure of microbial communities in thermophilic digester sludge. Methane production and biogas quality data were analyzed in batch anaerobic digesters containing QAC at 0, 15, 50, 100 and 150 mg/L. Increasing sanitizer concentration in the bioreactors negatively impacted methane production rate and biogas quality. Microbial community composition data was obtained through 16S rRNA gene sequencing from the QAC-contaminated sludges. Sequencing data showed no significant restructuring of the bacterial communities. However, significant restructuring was observed within the archaeal communities as QAC concentration increased. Further studies to confirm these effects on a larger scale and with a longer retention time are necessary.     

Influence of coagulation mechanisms and floc formation on filterability

Minimizing particles in water is a key goal for improving drinking water quality and safety.The media filtration process,as the last step of the solid–liquid separation process,is largely influenced by the characteristics of flocs,which are formed and controlled within the coagulation process.In a laboratory-based study,the impacts of the physical characteristics of flocs formed using aluminum sulfate on the filtration treatment of two comparative water samples were investigated using a photometric dispersion analyzer and a filterability apparatus.In general,the optimum dosage for maximizing filterability was higher than that for minimizing turbidity under neutral p H conditions.For a monomeric aluminum-based coagulant,the charge neutralization mechanism produced better floc characteristics,including floc growth speed and size,than the sweep flocculation mechanism.In addition,the charge neutralization mechanism showed better performance compared to sweep flocculation in terms of DOC removal and floc filterability improvement for both waters,and showed superiority in turbidity removal only when the raw water had high turbidity.For the different mechanisms,the ways that floc characteristics impacted on floc filterability also differed.The low variation in floc size distribution obtained under the charge neutralization mechanism resulted in the flocs being amenable to removal by filtration processes.For the sweep flocculation mechanism,increasing the floc size improved the settling ability of flocs,resulting in higher filter efficiency.     

Tissue distribution of perfluoroalkyl acids and health status in wild Mozambique tilapia (Oreochromis mossambicus) from Loskop Dam, Mpumalanga, South Africa

This study examined concentrations of 15 perfluoroalkyl acids (PFAAs) in tissues from male Mozambique tilapia (Oreochromis mossambicus) collected at Loskop Dam, Mpumalanga, South Africa in 2014 and 2016. Nine of the 15 PFAAs were detected frequently and were included in statistical analysis and included two of the most commonly known PFAAs, perfluorooctanesulfonic acid (PFOS) (median, 41.6 ng/g) and perfluorooctanoic acid (PFOA) (median, 0.0825 ng/g). Of the tissues measured, plasma (2016 and 2014 median, 22.2 ng/g) contained the highest PFAA burden followed by (in descending order): liver (median, 11.6 ng/g), kidney (median, 9.04 ng/g), spleen (median, 5.92 ng/g), adipose (median, 2.54 ng/g), and muscle (median, 1.11 ng/g). Loskop Dam tilapia have been affected by an inflammatory disease of the adipose tissue known as pansteatitis, so this study also aimed to investigate relationships between PFAA tissue concentrations and incidence of pansteatitis or fish health status. Results revealed that healthy tilapia exhibited an overall higher (p-value < 0.05) PFAA burden than pansteatitis-affected tilapia across all tissues. Further analysis showed that organs previously noted in the literature to contain the highest PFAA concentrations, such as kidney, liver, and plasma, were the organs driving the difference in PFAA burden between the two tilapia groups. Care must be taken in the interpretations we draw from not only the results of our study, but also other PFAA measurements made on populations (human and wildlife alike) under differing health status.     

Metabolomic analysis of the selection response of Drosophila melanogaster to environmental stress: are there links to gene expression and phenotypic traits?

We investigated the global metabolite response to artificial selection for tolerance to stressful conditions such as cold, heat, starvation, and desiccation, and for longevity in Drosophila melanogaster. Our findings were compared to data from other levels of biological organization, including gene expression, physiological traits, and organismal stress tolerance phenotype. Overall, we found that selection for environmental stress tolerance changes the metabolomic ¹H NMR fingerprint largely in a similar manner independent of the trait selected for, indicating that experimental evolution led to a general stress selection response at the metabolomic level. Integrative analyses across data sets showed little similarity when general correlations between selection effects at the level of the metabolome and gene expression were compared. This is likely due to the fact that the changes caused by these selection regimes were rather mild and/or that the dominating determinants for gene expression and metabolite levels were different. However, expression of a number of genes was correlated with the metabolite data. Many of the identified genes were general stress response genes that are down-regulated in response to selection for some of the stresses in this study. Overall, the results illustrate that selection markedly alters the metabolite profile and that the coupling between different levels of biological organization indeed is present though not very strong for stress selection at this level. The results highlight the extreme complexity of environmental stress adaptation and the difficulty of extrapolating and interpreting responses across levels of biological organization.     

Context dependency and generality of fever in insects

Fever can reduce mortality in infected animals. Yet, despite its fitness-enhancing qualities, fever often varies among animals. We used several approaches to examine this variation in insects. Texas field crickets (Gryllus texensis) exhibited a modest fever (1 °C increase in preferred body temperature, T _pref) after injection of prostaglandin, which putatively mediates fever in both vertebrates and invertebrates, but they did not exhibit fever during chronic exposure to heat-killed bacteria. Further, chronic food limitation and mating status did not affect T _pref or the expression of behavioural fever, suggesting limited context dependency of fever in G. texensis. Our meta-analysis of behavioural fever studies indicated that behavioural fever occurs in many insects, but it is not ubiquitous. Thus, both empirical and meta-analytical results suggest that the fever response in insects ‘is widespread, although certainly not inevitable’ (Moore 2002). We highlight the need for future work focusing on standardizing an experimental protocol to measure behavioural fever, understanding the specific mechanism(s) underlying fever in insects, and examining whether ecological or physiological costs often outweigh the benefits of fever and can explain the sporadic nature of fever in insects.     

Effects of exotic fish farms on bird communities in lake and marine ecosystems

Salmon farming is a widespread activity around the world, also known to promote diverse environmental effects on aquatic ecosystems. However, information regarding the impact of salmon farming on bird assemblages is notably scarce. We hypothesize that salmon farming, by providing food subsidies and physical structures to birds, will change their local community structure. To test this hypothesis, we conducted a seasonal monitoring of bird richness, abundance, and composition at paired salmon pen and control plots in two marine and two lake sites in southern Chile, from fall 2002 to summer 2004. Overall, salmon farming had no significant effects on species richness, but bird abundance was significantly and noticeably higher in salmon pens than in controls. Such aggregation was mainly accounted for by the trophic guilds of omnivores, diving piscivores, carrion eaters, and perching piscivores, but not by invertebrate feeders, herbivores, and surface feeders. Species composition was also significantly and persistently different between salmon pens and controls within each lake or marine locality. The patterns described above remained consistent across environment types and seasons indicating that salmon farming is changing the community structure of birds in both lake and marine habitats by promoting functional and aggregation responses, particularly by favoring species with broader niches. Such local patterns may thus anticipate potential threats from the ongoing expansion of the salmon industry to neighboring areas in Chile, resulting in regional changes of bird communities, toward a less diverse one and dominated by opportunistic, common, and generalist species such as gulls, vultures, and cormorants.     

Bechstein’s bats maintain individual social links despite a complete reorganisation of their colony structure

Several social mammals, including elephants and some primates, whales and bats, live in multilevel societies that form temporary subgroups. Despite these fission–fusion dynamics, group members often maintain long-term bonds. However, it is unclear whether such individual links and the resulting stable social subunits continue to exist after a complete reorganisation of a society, e.g. following a population crash. Here, we employed a weighted network analysis on 7,109 individual roosting records collected over 4 years in a wild Bechstein’s bat colony. We show that, in response to a strong population decline, the colony’s two stable social subunits fused into a non-modular social network. Nevertheless, in the first year after the crash, long-term bonds were still detectable, suggesting that the bats remembered previous individual relationships. Our findings are important for understanding the flexibility of animal societies in the face of dramatic changes and for the conservation of social mammals with declining populations.