Neutral Levels Research Articles

Cross-Scale Analyses of Animal and Human Gut Microbiome Assemblies from Metacommunity to Global Landscape

ABSTRACTAnimal (human) gut microbiomes have been coevolving with their hosts for many millions of years. Understanding how the coevolution shapes the processes of microbiome assembly and diversity maintenance is important but rather challenging. An effort may start with the understanding of how and why animals and humans may differ in their microbiome neutrality (stochasticity) levels. Here, we attempted to perform layered comparative stochasticity analyses across animal species (including humans), class, and kingdom scales, corresponding to microbial metacommunity, landscape, and global-landscape scales. By analyzing 4,903 microbiome samples from 274 animal species covering 4 major invertebrate classes and all 6 vertebrate classes and including 1,787 human gut microbiome samples, we discovered the following: (i) at the microbial metacommunity (animal species) scale, although the general trend of stochasticity (measured in the relationships between fundamental biodiversity/dispersal numbers of Hubbell’s neutral theory and host species phylogenetic timeline) seems continuous, there seems to be a turning point from animals to humans in the passing rate of neutrality tests (12% to 45% versus 100%). We postulate that it should be the human experiences from agricultural/industrial activities (e.g., diet effects) and frequent social/familial contacts that are responsible for the dramatically rising stochastic neutrality in human gut microbiomes. (ii) At the microbial landscape (animal class) and global landscape (animal kingdom) scales, neutrality is not detectable, suggesting that the landscape is niche differentiated—animal species may possess “home niches” for their coadapted microbiomes. We further analyze the reliabilities of our findings by using variable P value thresholds (type I error) and performing power analysis (type II error) of neutrality tests.IMPORTANCE Understanding how the coevolution (evolutionary time scale) and/or the interactions (ecological time scale) between animal (human) gut microbiomes and their hosts shape the processes of the microbiome assembly and diversity maintenance is important but rather challenging. An effort may start with the understanding of how and why animals and humans may differ in their microbiome neutrality (stochasticity) levels. Here, we attempted to perform layered comparative stochasticity analyses across animal species (including humans), class, and kingdom scales, corresponding to microbial metacommunity, landscape, and global-landscape scales by analyzing 4,903 microbiome samples from 274 animal species covering 4 major invertebrate classes and all 6 vertebrate classes, and including 1,787 human gut microbiome samples. The analyses were implemented by fitting the multisite neutral model and further augmented by checking false-positive and false-negative errors, respectively. It appears that there is a turning (tipping) point in the neutrality level from animal to human microbiomes.

A Quantitative Analysis on the Effect of Varying Nitrate Concentrations on pH levels on the Growth of Algae

The objective of this experiment was to determine what nitrate concentration and pH would provide the most optimal growth for algae. In order to determine this, algae from the American River was taken and grown in solutions with different concentrations of nitrate, and H+ ions. It was hypothesized that the algae would grow best in solutions with neutral pH levels or solutions with high nitrate concentrations. Different amounts of sodium nitrate were added to beakers with similar amounts of water and algae in order to create environments with varying concentrations of nitrate. Different amounts of NaOH and acetic acid were added to beakers with similar amounts of water and algae in order to simulate environments with varying pH levels. This experiment was conducted in order to determine how fertilizer runoffs affect algal growth. Fertilizer run offs carry nitrate ions into rivers and lakes, which cause algal blooms to form. It was hypothesized that as the concentration of nitrate increases, the growth rate of the algae would also increase. This is due to the fact that the literature supports the idea that as nitrate is added to rivers and lakes the number of algae present increases. The results from the experiment demonstrated that the most optimal concentration of nitrate in the water for algal growth was in between 1-2 Molar and that the most optimal pH for algal growth was in between 7-8.

Leachability of microplastic from different plastic materials

The use of plastic has become common. Large amounts of plastic waste are disposed in landfill without the ability to biodegrade. These plastic materials often disintegrate into microplastic that end up in the leachate, a wastewater stream containing harmful contaminants extracted from the plastic. These particles can eventually contaminate the groundwater. The main objective of this research is to evaluate the leaching of microplastics originated from different types of plastic materials and to evaluate the role of pH in the disintegration process. In this study, seven different types of plastic wastes were investigated. These include Polyethylene Terephthalate (PET), High-Density Polyethylene (HDPE), Polyvinyl Chloride (PVC), Low-Density Polyethylene (LDPE), Polypropylene (PP), Polystyrene (PS), and Polycarbonate (PC). Batch leaching tests were carried out to generate leachate from these plastic materials. The leachate generated from the test was eventually tested for different water quality parameters. Characterization of microplastic particles was conducted using SEM-EDX, FT-IR and particle size analyser. Results revealed that leachates from PET, LDPE, PS and PP contained fibres in addition to other particles. Results showed that PC (19868 items/L) has the largest, while PET (4099 items/L) has the smallest number of microplastic particles per litre. The results indicated PC (184.1 mg/L) has the highest concentration in mass/L and PS (43.1 mg/L) has the smallest concentrations. The study also revealed pH has a significant impact on the leachability of plastic materials and the turbidity of the leachate. Acidic and basic pH levels are more aggressive to plastic materials than neutral pH levels. SEM analysis found that PET and LDPE leachates contained fibres. EDX analysis conducted on the microplastics indicated the presence of elements indicative of the plastic types. FT-IR analysis was not conclusive for all the materials. Microplastic sizes were mostly small and less than 500 nm for most of the samples. The study concludes that the microplastic particles can disintegrate from the original plastic materials under suitable conditions. The outcome of this study can be used for efficient use of different plastic materials and management of its eventual waste materials.

Large-Area, Two-Dimensional MoS2 Exfoliated on Gold: Direct Experimental Access to the Metal-Semiconductor Interface.

Two-dimensional semiconductors such as MoS2 are promising for future electrical devices. The interface to metals is a crucial and critical aspect for these devices because undesirably high resistances due to Fermi level pinning are present, resulting in unwanted energy losses. To date, experimental information on such junctions has been obtained mainly indirectly by evaluating transistor characteristics. The fact that the metal–semiconductor interface is typically embedded, further complicates the investigation of the underlying physical mechanisms at the interface. Here, we present a method to provide access to a realistic metal–semiconductor interface by large-area exfoliation of single-layer MoS2 on clean polycrystalline gold surfaces. This approach allows us to measure the relative charge neutrality level at the MoS2–gold interface and its spatial variation almost directly using Kelvin probe force microscopy even under ambient conditions. By bringing together hitherto unconnected findings about the MoS2–gold interface, we can explain the anomalous Raman signature of MoS2 in contact to metals [ACS Nano. 7, 2013, 11350] which has been the subject of intense recent discussions. In detail, we identify the unusual Raman mode as the A1g mode with a reduced Raman shift (397 cm–1) due to the weakening of the Mo–S bond. Combined with our X-ray photoelectron spectroscopy data and the measured charge neutrality level, this is in good agreement with a previously predicted mechanism for Fermi level pinning at the MoS2–gold interface [Nano Lett.14, 2014, 1714]. As a consequence, the strength of the MoS2–gold contact can be determined from the intensity ratio between the reduced A1greduced mode and the unperturbed A1g mode.

Naturally Acquired SARS-CoV-2 Immunity Persists for Up to 11 Months Following Infection.

Background Characterizing the kinetics of the antibody response to severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) is of critical importance to developing strategies that may mitigate the public health burden of coronavirus disease 2019 (COVID-19). We conducted a prospective, longitudinal analysis of COVID-19 convalescent plasma donors at multiple time points over an 11-month period to determine how circulating antibody levels change over time following natural infection. Methods From April 2020 to February 2021, we enrolled 228 donors. At each study visit, subjects either donated plasma or had study samples drawn only. Anti–SARS-CoV-2 donor testing was performed using the VITROS Anti–SARS-CoV-2 Total and IgG assays and an in-house fluorescence reduction neutralization assay. Results Anti–SARS-CoV-2 antibodies were identified in 97% of COVID-19 convalescent donors at initial presentation. In follow-up analyses, of 116 donors presenting at repeat time points, 91.4% had detectable IgG levels up to 11 months after symptom recovery, while 63% had detectable neutralizing titers; however, 25% of donors had neutralizing levels that dropped to an undetectable titer over time. Conclusions Our data suggest that immunological memory is acquired in most individuals infected with SARS-CoV-2 and is sustained in a majority of patients for up to 11 months after recovery. Clinical Trials Registration. NCT04360278.

Adaptive neuro fuzzy inference system based decoupled control for neutral point clamped multi level inverter fed induction motor drive

The presence of an integrator in a reference model of a rotor flux-based model reference adaptive system (RF-MRAS) and non-linearity of the inverter in the output voltage degrade the speed response of the sensorless operation of the electric drive system in terms of DC drift, initial value issues, and inaccurate voltage acquisition. To improve the speed response, a compensating voltage component is supplemented by an amending integrator. The compensating voltage is a coalition of drift and offset voltages, and reduces DC drift and initial value issues. During low-speed operation, inaccurate voltage acquisition distorts the stator voltage critically, and it becomes considerable when the stator voltage of the machine is low. Implementing a three-level neutral point clamped inverter in speed-sensorless decoupled control of an induction motor improves the performance of the drive with superior quality of inverter output voltage. Further, the performance of the induction motor drive is improved by replacing the proportional-integral (PI) controller in the adaption mechanism of RF-MRAS with an adaptive neuro-fuzzy inference system (ANFIS) controller. A prototype model of the three-level neutral point clamped inverter (3L-NPC)-fed induction motor drive is fabricated in a laboratory, and its performance for a RF-MRAS, modified RFMRAS, and modified RFMRAS using ANFIS are compared using different benchmark tests.

Numerical investigation on the transmission and dispersion of aerosols in a 7-stories building drainage system

In previous reports, the positive SARS-CoV-2 nucleic acid was detected in the fecal samples from confirmed pneumonia patients, suggesting a high probability of the fecal-oral transmission. To date, however, the role played by the drainage system of a high-rise building in the virus transmission is not clear and especially studies on the dynamics mechanism behind is scarce. From this point of view, the present work carries out a computational fluid dynamics (CFD) modeling to investigate the effects of the water seal effectiveness of the floor drain, the negative/positive pressures (P1, P2) in the bathroom, temperature differential (ΔT), outside wind velocity (v), the piping fittings and the negative pressure at the cowl (P3) on the transmission of the virus-laden aerosol particles in a drainage system of a typical 7-storeys residential building. The CFD models are first validated by the previous experiments in literature. Numerical results imply that the drainage system might play an essential role to the virus transmission. Then, results indicate that, the leakage risk of the aerosol particles via the floor drain with inefficient water-seal (UFD) mainly exists at the upper floors above the neutral pressure level (NPL). Besides, the negative and positive pressures at the bathroom can enhance and reduce the exposure risk of aerosol particles from the corresponding UFD, respectively. The ΔT increasing does not modify the location of the NPL. Moreover, the exposure risk of aerosol particles can be effectively avoided by the well water-sealed floor drains and/or the presence of a proper negative pressure at the cowl on the top floor. Finally, based on the CFD results, several protection suggestions on the drainage system and human activities are provided.

Extent of bioleaching and bioavailability reduction of potentially toxic heavy metals from sewage sludge through pH-controlled fermentation

Utilization of anaerobically stabilized sewage sludge on arable lands serve as a renewable alternative to chemical fertilizers as it enables recycling of valuable nutrients to food chain. However, probable presence of heavy metals in sewage sludge restricts the use of stabilized sludge on lands. In this study, a novel approach based on pH-controlled fermentation and anaerobic metal bioleaching was developed to reduce ecotoxicity potential of fermented sludge prior to its land application. Sewage sludge was subjected to pH-controlled fermentation process at acidic, neutral, and alkaline pH levels with the aim of increasing metal solubilization and decreasing bioavailable metal fractions through anaerobic bioleaching. Alkaline reactor performed the best among all reactors and resulted in 3-fold higher hydrolysis (34%) and 6-fold higher acidification (19%) efficiencies along with 43-fold (in average) higher metal solubilization than that of neutral pH reactor. As a result of alkaline fermentation, 32–57% of the metals remained as bioavailable and 34–59% of the metals were encapsulated as non-bioavailable within solid fraction of fermented sludge (biosolid), whereas 8–12% of total metal was solubilized into fermentation liquor. Our results reveal that anaerobic bioleaching through alkaline fermentation enables biosolid production with less metal content and low bioavailability, facilitating its utilization for agricultural purposes.

Structure-Specific and Individual-Dependent Metabolization of Human Milk Oligosaccharides in Infants: A Longitudinal Birth Cohort Study

To follow human milk oligosaccharide (HMO) biosynthesis and in vivometabolization, mother milk and infant feces from 68 mother–infant dyads at 2, 6, and 12 weeks postpartum were analyzed, with 18 major HMOs quantitated. Fucosylated and neutral core HMO levels in milk were dependent on mothers’ Lewis/Secretor status, whereas most sialylated HMO levels were independent. Infant fecal excretion of HMOs gradually declined with age, especially for neutral core structures. Although decreasing in absolute concentrations in milk during lactation, the relative abundance of total fucosylated HMOs increased in both milk and feces. Mono-fucosylated HMOs were more consumed than those decorated with two fucose moieties. More (α2-3)-sialylated HMOs were degraded than (α2-6)-sialylated HMOs. The transition speed of HMO metabolization from nonspecific or structure-specific consumption stage to the complete consumption stage was individual-dependent. Variation was associated with mode and place of delivery, where caesarean section or early exposure to hospital environment delayed the transition.

Neutralizing antibody levels are highly predictive of immune protection from symptomatic SARS-CoV-2 infection.

Predictive models of immune protection from COVID-19 are urgently needed to identify correlates of protection to assist in the future deployment of vaccines. To address this, we analyzed the relationship between in vitro neutralization levels and the observed protection from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection using data from seven current vaccines and from convalescent cohorts. We estimated the neutralization level for 50% protection against detectable SARS-CoV-2 infection to be 20.2% of the mean convalescent level (95% confidence interval (CI) = 14.4-28.4%). The estimated neutralization level required for 50% protection from severe infection was significantly lower (3% of the mean convalescent level; 95% CI = 0.7-13%, P = 0.0004). Modeling of the decay of the neutralization titer over the first 250 d after immunization predicts that a significant loss in protection from SARS-CoV-2 infection will occur, although protection from severe disease should be largely retained. Neutralization titers against some SARS-CoV-2 variants of concern are reduced compared with the vaccine strain, and our model predicts the relationship between neutralization and efficacy against viral variants. Here, we show that neutralization level is highly predictive of immune protection, and provide an evidence-based model of SARS-CoV-2 immune protection that will assist in developing vaccine strategies to control the future trajectory of the pandemic.

Serum IgG1 and IgG4 could contribute to partial control of viral rebound in chronically HIV-1-infected patients.

Few studies have investigated chronically infected individuals after antiretroviral therapy (ART) interruption (ATI, analytical therapy interruption); thus, we investigated the association between some HIV-specific antibodies and viral control. All enrolled patients were previously described in the APACHE study. Briefly, the study was conducted on HIV-1 chronically infected patients, with HIV-RNA less than 50 copies/ml for at least 10 years, CD4+ cell count greater than 500 cells/μl and HIV-DNA less than 100 copies/106 PBMC. The ART regimen in use at the time of ATI was resumed at confirmed viral rebound (CVR, defined as two consecutive HIV-RNA >50 copies/ml). Collection of sera and analysis of both binding antibodies (BAbs) and neutralizing antibodies (NAbs) was performed at three different time points: ATI, CVR and time of viral re-suppression after ART resumption. IgG subclasses (IgG1, IgG2, IgG3 and IgG4) from the four patients with highest levels of neutralization were found to block viral infection. All patients had CVR after ATI at a median time of 21 days (14-56). After ART resumption, all the enrolled patients achieved HIV-RNA less than 50 copies/ml in 42 days (21-98). We observed a strong increase of either BAbs and NAbs titers from ATI to viral re-suppression in one patient, who showed the longest period of virus undetectability during ATI. In this patient, BAbs and NAbs specifically belonged to both IgG1 and IgG4 subclasses, directed to env antigen. env-specific NAbs and BAbs belonging to IgG1, IgG4 subclasses could be helpful to monitor long-term responses able to control virus replication and eradicate HIV infection.

The path to find an HIV vaccine.

The path to find an HIV vaccine.

The perception of pre-university students on STEM

STEM is an integrated teaching and learning approach in Science, Technology, Engineering and Mathematic. The decreasing enrolment of students in STEM-field is alarming and impacting the industry as well as the university students’ intake. This study is focusing on one hundred of pre-university (foundation) students by looking at their understanding on STEM education and the impacts of STEM module in nurturing their interest on STEM. The study applied naturalistic inquiry to assess their perceptions of STEM prior and subsequently after involve in a STEM module activities. The results showed that majority of students are female and from different background, they are interested in learning science shown by the increase of agreement to 38% and 40% after the activity with the decrease in the percentage of neutral and disagree level. The percentage of interest on STEM was decreased after the activity. However, the level of confident about their ability towards science was increased. The confident level lead the respondents to choose career related to science/STEM based on the increase level of agreement from 22% to 28% and from 24% to 32% for strongly agree and agree relatively. Hence, the outreach with attractive activities would potentially add value for students’ intrinsic motivation for science and science learning.

Immunity to random fluctuations induced by interface trap variability in Si gate-all-around n-nanowire field-effect transistor devices

The impact of variations in the donor and acceptor interface trap distributions on the fluctuation characteristics of 7-nm-node Si gate-all around n-nanowire FET (n-NWFETs) is analyzed in a hardware-calibrated quantum-corrected three-dimensional (3D) drift–diffusion (DD) numerical simulation framework. Shifting the energy position of the peak in the acceptor trap density distribution (Dit) induces greater surface potential fluctuations and carrier mobility degradation compared with variation of the donor traps. It is found that single-charge traps (SCTs) and random interface traps (RITs) induce larger V $$_{\text {T}}$$ and drain-induced barrier lowering (DIBL) variations, along with charge neutrality level (CNL) variations induced by interface trap fluctuations. The Si n-NWFET shows better immunity to interface trap variability when the CNL is located between the midgap and the conduction-band edge. For future sub-7-nm high-performance NWFET logic devices, such interface trap variability will be one of the major sources of random fluctuations at the device level.

Toward Largely Enhanced Toughness and Balanced Strength in PA1012/EPDM Blends via Synergistic Effect of Sacrificial Bonds and Network Structure

AbstractHere, zinc‐neutralized ethylene propylene diene monomer (EPDM) ionomers with different neutralization levels are prepared through melt blending, and are then incorporated with polyamide 1012 (PA1012) to fabricate PA1012/EPDM ionomer blends. Interestingly, complex crosslinking networks are formed in the blends due to the construction of sacrificial bonds (Zn2+‐carboxyl, Zn2+‐amide). The as‐formed network structure and sacrificial bond endow the PA/EPDM blends with largely enhanced toughness (16 times higher than that of neat PA), as well as balanced strength and stiffness. Meanwhile, the rheological behaviors of PA1012/EPDM ionomer blends indicate their relative low melting viscosity, which can avoid the processing shortcomings of plastics toughened with rubber. Moreover, PA1012/EPDM ionomer blends show obvious gelation behavior, and a maximum notched Izod impact strength exhibited at the gel point, in which unique double network structure can be observed obviously, indicating that there is a corresponding correlation between the rheological and mechanical parameters. Furthermore, the supper‐toughening mechanism of PA1012/EPDM ionomer blends at gel point is explored, which origins from the large deformation and cavitation of rubber particles and the destruction of special double network morphologies. This study provides a novel and effective strategy to fabricate PA materials with outstanding toughness and excellent strength simultaneously.

Characteristics of Al/Ge Schottky and ohmic contacts at low temperatures

Schottky barrier contact has been fabricated by thermal deposition of Al on (100) p-Ge (impurity concentratioñ1010/cm3 at 80K) that shows n-type conductivity above 180K due to thermally generated carriers. Both p and n-type Ge exhibits ideal Schottky behavior with low reverse current and near unity ideality factors obtained from the linear form of temperature dependent current-voltage (I–V) characteristics. The diode current at various temperatures change its direction at non-zero applied bias that reflects a shift in position of charge neutrality level (CNL) from the Fermi level of Ge. With the rise in temperature, Schottky barrier height (SBH) steadily increases for p-Ge that can be understood on the basis of observed variation in CNL. Values of SBH determined from the zero bias Richardson plot agrees well with that estimated from the Schottky-Mott rule for strongly pinned interface. Activation energies are determined from the Richardson plot at various forward voltages and found to decrease with applied bias for n-Ge but reduces to zero for p-Ge that shows work function similar to Al. Annealing of Al/Ge induces regrowth of p-type Al doped Ge layer that exhibits gradual reduction of Al concentration towards p-Ge crystal. Al doped Ge (p+)/Ge (p) junction thus fabricated shows linear I–V characteristics in the extrinsic region (below 180K). In the intrinsic region (above 180K), rectification is observed in the I–V curve due to temperature dependent change in conductivity of both Al doped Ge layer and Ge crystal.

Impact of pathogen reduction methods on immunological properties of the COVID-19 convalescent plasma.

Background and objectivesCOVID‐19 convalescent plasma is an experimental treatment against SARS‐CoV‐2. The aim of this study is to assess the impact of different pathogen reduction methods on the levels and virus neutralizing activity of the specific antibodies against SARS‐CoV2 in convalescent plasma.Materials and methodsA total of 140 plasma doses collected by plasmapheresis from COVID‐19 convalescent donors were subjected to pathogen reduction by three methods: methylene blue (M)/visible light, riboflavin (R)/UVB and amotosalen (A)/UVA. To conduct a paired comparison, individual plasma doses were divided into 2 samples that were subjected to one of these methods. The titres of SARS‐CoV2 neutralizing antibodies (NtAbs) and levels of specific immunoglobulins to RBD, S‐ and N‐proteins of SARS‐CoV‐2 were measured before and after pathogen reduction.ResultsThe methods reduced NtAbs titres differently: among units with the initial titre 80 or above, 81% of units remained unchanged and 19% decreased by one step after methylene blue; 60% were unchanged and 40% decreased by one step after amotosalen; after riboflavin 43% were unchanged and 50% (7%, respectively) had a one‐step (two‐step, respectively) decrease. Paired two‐sample comparisons (M vs. A, M vs. R and A vs. R) revealed that the largest statistically significant decrease in quantity and activity of the specific antibodies resulted from the riboflavin treatment.ConclusionPathogen reduction with methylene blue or with amotosalen provides the greater likelihood of preserving the immunological properties of the COVID‐19 convalescent plasma compared to riboflavin.

Exercise for affect and enjoyment in overweight or obese males: a comparison of high-intensity interval training and moderate-intensity continuous training

ABSTRACT High-intensity interval training (HIIT) is effective for generating positive cardiovascular health and fitness benefits. This study compared HIIT and moderate-intensity continuous training (MICT) for affective state and enjoyment in sedentary males with overweight or obesity. Twenty-eight participants performed stationary cycling for 6 weeks × 3 sessions/week. Participants were randomly allocated to HIIT (N=16) (10 × 1-minute intervals at ~90% peak heart rate) or MICT (N=12) (30 minutes at 65-75% peak heart rate). Affective state changes were assessed after 6-weeks training. Enjoyment and acute change in affect were assessed after individual training sessions. HIIT participants reported improved positive affect following 6 weeks training (∆ 3.6 ± 4.6, p = 0.007, effect size d = 0.70), without corresponding improvement in negative affect (p = 0.48, d = -0.19). MICT did not induce any improvement in positive affect (p = 0.56, d = 0.16) or negative affect (p = 0.23, d = -0.41). Enjoyment ratings were comparable for both exercise formats (HIIT: 4.4 ± 0.4 on a 7-point scale; MICT: 4.3 ± 0.3; p = 0.70, d = 0.15). Six weeks of HIIT induced improvement in positive affect in sedentary participants with overweight or obesity. Enjoyment of training was only slightly above neutral levels for both training formats. What’s already known about this topic? Exercise training can improve general affect however the optimal exercise characteristics for improving affect are unclear. Studies assessing the relative enjoyment of HIIT in comparison to MICT have largely been equivocal to date. What does this study add? HIIT can improve affective state in males with overweight or obesity. Six weeks of stationary cycling HIIT were rated as only mildly enjoyable, comparable to ratings for MICT.

Unraveling the mechanism of long-term bisphenol S exposure disrupted ovarian lipids metabolism, oocytes maturation, and offspring development of zebrafish

Bisphenol S (BPS) acts as a xenoestrogen and disturbs the female reproductive system; however, the underlying mechanism has not been elucidated. In this study, the effect of chronic BPS exposure (1 μg/L and 100 μg/L) on ovarian lipid metabolism in zebrafish was investigated to determine its influence on adult reproductive capacity and offspring development. The results showed that long-term (240 days) exposure to BPS induced lipid accumulation in the ovaries by promoting the transport of more lipids from the circulation to the ovaries and by upregulating triacylglycerol synthesis-related genes. Significantly increased expression of cpt2, acadm, acadl, and pparα, which are involved in β-oxidation in the ovarian mitochondria, indicated that more energy was provided for oocyte maturation in exposed zebrafish ovaries. Thus, the proportion of full-grown stage oocytes in ovaries and egg reproduction were elevated at an accelerated rate, which earlier than normal reproductive cycle (8–10 days posts pawning). Moreover, the maternally BPS-exposed F1 embryos (2 h post-spawning, hpf) showed higher neutral lipid levels, impaired hatching capacity, and increased occurrence of larval deformities. All these findings demonstrated that stimulated lipid synthesis and β-oxidation in zebrafish ovaries significantly contribute to BPS-induced oocyte precociousness with subsequent effects on the development of unexposed offspring. This study provides new insight into the impact of xenoestrogens on oviparous reproduction in females and offspring development from the perspective of ovarian lipid metabolism.

PLUME-MoM-TSM 1.0.0: a volcanic column and umbrella cloud spreading model

Abstract. In this paper, we present a new version of PLUME-MoM, a 1-D integral volcanic plume model based on the method of moments for the description of the polydispersity in solid particles. The model describes the steady-state dynamics of a plume in a 3-D coordinate system, and a modification of the two-size moment (TSM) method is adopted to describe changes in grain size distribution along the plume, associated with particle loss from plume margins and with particle aggregation. For this reason, the new version is named PLUME-MoM-TSM. For the first time in a plume model, the full Smoluchowski coagulation equation is solved, allowing us to quantify the formation of aggregates during the rise of the plume. In addition, PLUME-MOM-TSM allows us to model the phase change of water, which can be either magmatic, added at the vent as liquid from external sources, or incorporated through ingestion of moist atmospheric air. Finally, the code includes the possibility to simulate the initial spreading of the umbrella cloud intruding from the volcanic column into the atmosphere. A transient shallow-water system of equations models the intrusive gravity current, allowing computation of the upwind spreading. The new model is applied first to the eruption of the Calbuco volcano in southern Chile in April 2015 and then to a sensitivity analysis of the upwind spreading of the umbrella cloud to mass flow rate and meteorological conditions (wind speed and humidity). This analysis provides an analytical relationship between the upwind spreading and some observable characteristic of the volcanic column (height of the neutral buoyancy level and plume bending), which can be used to better link plume models and volcanic-ash transport and dispersion models.