Biocénose pélagique du lac oligomésotrophe de Poméranie (Pologne) : étude des communautés de la boucle mocrobienne et du pytoplancton

Cette étude présente des résultats concernant l'abondance et la biomasse des principales communautés de la boucle microbienne (bactéries hétérotrophes, picoplancton autotrophe, flagellés hétérotrophes, protistes ciliés) et des nano- et microalgues dans le grand (525 ha) et profond (48 m) lac oligomésotrophe Bobifcigskie Wielkie situé en Poméranie de l'ouest (Pologne). Les échantillons d'eau ont été prélevés en zone pélagique, en 1996. Dans la classe de taille du picoplancton, ce sont les bactéries hétérotrophes qui constituent le groupe trophique le plus abondant. Leur biomasse couplée à celle du picoplancton autotrophe beaucoup moins abondant (de 3,5 à 5,4 µg·C·L-1), constituait de 15 % à 22 % de la biomasse microbienne totale. La biomasse des protistes flagellés hétérotrophes et celle des protistes ciliés étaient proches (3,0-3,8 µg·C·L-1) et constituaient, en fonction de la profondeur de prélèvement, de 8 % à 24 % de la biomasse totale. Le phytoplancton de taille supérieure à 2,0 µm représentait la plus grande partie de la biomasse totale, à savoir de 50 % à 78 % (8,4-27,5 µg·C·L-1). Il était dominé, en ce qui concerne la taille des organismes, par le microplancton. Dans les couches supérieures du lac, les diatomées et les cryptophycées étaient les plus nombreuses, alors qu'en profondeur c'était les cyanobactéries filamenteuses du genre Planktothrix qui étaient les plus abondantes.This study presents results of investigations on abundance and biomass of the main communities of the microbial loop (heterotrophic bacteria, autotrophic picoplankton, heterotrophic flagellates, ciliated protozoa) as well as nano- and microalgae in the large (525 ha) and deep (48 m) oligo-mesotrophic lake Bobifcigskie Wielkie located in West Pomerania, Poland. Samples were taken from the pelagial zone in 1996. Within organisms of picoplankton size the heterotrophic bacteria were the most abundant trophic group. Their biomass, together with the much lower abundant autotrophic picoplankton (3.5 to 5.4 µg·C L-1), constituted 15% to 22% of the total microbial biomass. The sum of biomasses of heterotrophic flagellates and ciliated protozoa was similar at all depth (3.0-3.8 µg·C·L-1), ranging between 8-24% of total biomass. Phytoplankton organisms larger than 2.0 µm represented the biggest part of the total microbial biomass, i.e. from 50% to 78% (8.4-27.5 µg·C·L-1). The microplankton constitutes the largest part of the phytoplanktonic biomass. Whereas the diatoms and cryptomonads were the most abundant in the upper layers of the lake. The filamentous cyanobacteria of the genus Planktothrix dominated in the deeper waters

Distribution du picoplancton autotrophe dans la zone pélagique d'un lac méromictique (Lac Czane, Pologne)

La composition, l'abondance et la biomasse de la communauté du picoplancton autotrophe (PPA, 0,2-2 m) ont été examinées dans un lac situé en Pologne et récemment considéré comme méromictique, le lac Czarne. Les échantillons d'eau ont été prélevés tous les mètres dans la colonne d'eau, en mars et en juillet 1998. Pendant ces deux dates, le PPA se caractérisait par des changements significatifs de densité dans la colonne d'eau. Au printemps, l'abondance la plus forte a été observée à 9 m (2,1·105 cellules·mL-1) tandis qu'en été elle est observée à 5 m (3,1·105 cellules·mL-1). À toutes les profondeurs, le PPA était dominé par des Cyanobactéries. Au printemps, dominent les cellules libres de picocyanobactéries, contrairement à l'été où les cellules coloniales étaient prépondérantes. La contribution des cellules eucaryotes était faible en termes d'abondance (10 µg C·L-1 were recorded to the depth of 14 m, while during the second session biomass clearly concentrated in the upper part of the water column, to a depth of 7 m. Within PPA, usually Pcy dominated in terms of biomass. In March their contribution to the total PPA biomass varied from 35% to 88% (mean: 67%) and in July from 65% to 100% (mean: 88%). PEA biomass was higher in March than in July and mean values were respectively 3.0 µg C·L-1 and 0.3 µg C·L-1, accounting for 33% and 12% of the total PPA biomass. In July, PAE biomass was everywhere lower than Pcy biomass. In contrast, in March, PAE biomass exceeded Pcy biomass at some depths in the lower part of the water column. The contribution of PAE to the total PPA biomass was higher than to the total PPA abundance, especially in March, when PAE were the most numerous. Generally, the contribution of eukaryotic cells was smaller in terms of abundance and much higher in terms of biomass, because of the larger mean size of cells

Modeling nutrient removal and energy consumption in an advanced activated sludge system under uncertainty

Activated sludge models are widely used to simulate, optimize and control performance of wastewater treatment plants (WWTP). For simulation of nutrient removal and energy consumption, kinetic parameters would need to be estimated, which requires an extensive measurement campaign. In this study, a novel methodology is proposed for modeling the performance and energy consumption of a biological nutrient removal activated sludge system under sensitivity and uncertainty. The actual data from the wastewater treatment plant in Slupsk (northern Poland) were used for the analysis. Global sensitivity analysis methods accounting for interactions between kinetic parameters were compared with the local sensitivity approach. An extensive procedure for estimation of kinetic parameters allowed to reduce the computational effort in the uncertainty analysis and improve the reliability of the computational results. Due to high costs of measurement campaigns for model calibration, a modification of the Generalized Likelihood Uncertainty method was applied considering the location of measurement points. The inclusion of nutrient measurements in the aerobic compartment in the uncertainty analysis resulted in percentages of ammonium, nitrate, ortho-phosphate measurements of 81%, 90%, 78%, respectively, in the 95% confidence interval. The additional inclusion of measurements in the anaerobic compartment resulted in an increase in the percentage of ortho-phosphate measurements in the aerobic compartment by 5% in the confidence interval. The developed procedure reduces computational and measurement efforts, while maintaining a high compatibility of the observed data and model predictions. This enables to implement activated sludge models also for the facilities with a limited availability of data

Effects of Steel Fibers (SF) and Ground Granulated Blast Furnace Slag (GGBS) on Recycled Aggregate Concrete

[EN] Recycled aggregate is a good option to be used in concrete production as a coarse aggregate that results in environmental benefits as well as sustainable development. However, recycled aggregate causes a reduction in the mechanical and durability performance of concrete. On the other hand, the removal of industrial waste would be considerably decreased if it could be incorporated into concrete production. One of these possibilities is the substitution of the cement by slag, which enhances the concrete poor properties of recycled aggregate concrete as well as provides a decrease in cement consumption, reducing carbon dioxide production, while resolving a waste management challenge. Furthermore, steel fiber was also added to enhance the tensile capacity of recycled aggregate concrete. The main goal of this study was to investigate the characteristics of concrete using ground granulated blast-furnace slag (GGBS) as a binding material on recycled aggregate fibers reinforced concrete (RAFRC). Mechanical performance was assessed through compressive strength and split tensile strength, while durability aspects were studied through water absorption, acid resistance, and dry shrinkage. The results detected from the different experiments depict that, at an optimum dose (40% RCA, 20%GGBS, and 2.0%), compressive and split tensile strength were 39% and 120% more than the reference concrete, respectively. Furthermore, acid resistance at the optimum dose was 36% more than the reference concrete. Furthermore, decreased water absorption and dry shrinkage cracks were observed with the substitution of GGBS into RAFRC.SIThe authors extend their appreciation to the Deanship of Scientific Research at King Khalid University for funding this work through a group research program under grant number RGP. 2/129/42 and Taif University Researchers Supporting Project grant number [TURSP-2020/324]

Enhanced Visual Temporal Resolution in Autism Spectrum Disorders

Cognitive functions that rely on accurate sequencing of events, such as action planning and execution, verbal and nonverbal communication, and social interaction rely on well-tuned coding of temporal event-structure. Visual temporal event-structure coding was tested in 17 high-functioning adolescents and adults with autism spectrum disorder (ASD) and mental- and chronological-age matched typically-developing (TD) individuals using a perceptual simultaneity paradigm. Visual simultaneity thresholds were lower in individuals with ASD compared to TD individuals, suggesting that autism may be characterised by increased parsing of temporal event-structure, with a decreased capability for integration over time. Lower perceptual simultaneity thresholds in ASD were also related to increased developmental communication difficulties. These results are linked to detail-focussed and local processing bias

An extended multisensory temporal binding window in autism spectrum disorders

Autism spectrum disorders (ASD) form a continuum of neurodevelopmental disorders, characterized by deficits in communication and reciprocal social interaction, as well as by repetitive behaviors and restricted interests. Sensory disturbances are also frequently reported in clinical and autobiographical accounts. However, surprisingly few empirical studies have characterized the fundamental features of sensory and multisensory processing in ASD. The current study is structured to test for potential differences in multisensory temporal function in ASD by making use of a temporally dependent, low-level multisensory illusion. In this illusion, the presentation of a single flash of light accompanied by multiple sounds often results in the illusory perception of multiple flashes. By systematically varying the temporal structure of the audiovisual stimuli, a “temporal window” within which these stimuli are likely to be bound into a single perceptual entity can be defined. The results of this study revealed that children with ASD report the flash-beep illusion over an extended range of stimulus onset asynchronies relative to children with typical development, suggesting that children with ASD have altered multisensory temporal function. These findings provide valuable new insights into our understanding of sensory processing in ASD and may hold promise for the development of more sensitive diagnostic measures and improved remediation strategies

Perinatal Asphyxia Affects Rat Auditory Processing: Implications for Auditory Perceptual Impairments in Neurodevelopmental Disorders

Perinatal asphyxia, a naturally and commonly occurring risk factor in birthing, represents one of the major causes of neonatal encephalopathy with long term consequences for infants. Here, degraded spectral and temporal responses to sounds were recorded from neurons in the primary auditory cortex (A1) of adult rats exposed to asphyxia at birth. Response onset latencies and durations were increased. Response amplitudes were reduced. Tuning curves were broader. Degraded successive-stimulus masking inhibitory mechanisms were associated with a reduced capability of neurons to follow higher-rate repetitive stimuli. The architecture of peripheral inner ear sensory epithelium was preserved, suggesting that recorded abnormalities can be of central origin. Some implications of these findings for the genesis of language perception deficits or for impaired language expression recorded in developmental disorders, such as autism spectrum disorders, contributed to by perinatal asphyxia, are discussed

Using time perception to explore implicit sensitivity to emotional stimuli in autism spectrum disorder

Establishing whether implicit responses to emotional cues are intact in autism spectrum disorder (ASD) is fundamental to ascertaining why their emotional understanding is compromised. We used a temporal bisection task to assess for responsiveness to face and wildlife images that varied in emotional salience. There were no significant differences between an adult ASD and comparison group, with both showing implicit overestimation of emotional stimuli. Further, there was no correlation between overestimation of emotional stimuli and autistic traits in undergraduate students. These data do not suggest a fundamental insensitivity to the arousing content of emotional images in ASD, or in individuals with a high degree of autistic traits. The findings have implications for understanding how emotional stimuli are processed in ASD

Identification of Metabolites in the Normal Ovary and Their Transformation in Primary and Metastatic Ovarian Cancer

In this study, we characterized the metabolome of the human ovary and identified metabolic alternations that coincide with primary epithelial ovarian cancer (EOC) and metastatic tumors resulting from primary ovarian cancer (MOC) using three analytical platforms: gas chromatography mass spectrometry (GC/MS) and liquid chromatography tandem mass spectrometry (LC/MS/MS) using buffer systems and instrument settings to catalog positive or negative ions. The human ovarian metabolome was found to contain 364 biochemicals and upon transformation of the ovary caused changes in energy utilization, altering metabolites associated with glycolysis and β-oxidation of fatty acids—such as carnitine (1.79 fold in EOC, p<0.001; 1.88 fold in MOC, p<0.001), acetylcarnitine (1.75 fold in EOC, p<0.001; 2.39 fold in MOC, p<0.001), and butyrylcarnitine (3.62 fold, p<0.0094 in EOC; 7.88 fold, p<0.001 in MOC). There were also significant changes in phenylalanine catabolism marked by increases in phenylpyruvate (4.21 fold; p = 0.0098) and phenyllactate (195.45 fold; p<0.0023) in EOC. Ovarian cancer also displayed an enhanced oxidative stress response as indicated by increases in 2-aminobutyrate in EOC (1.46 fold, p = 0.0316) and in MOC (2.25 fold, p<0.001) and several isoforms of tocopherols. We have also identified novel metabolites in the ovary, specifically N-acetylasparate and N-acetyl-aspartyl-glutamate, whose role in ovarian physiology has yet to be determined. These data enhance our understanding of the diverse biochemistry of the human ovary and demonstrate metabolic alterations upon transformation. Furthermore, metabolites with significant changes between groups provide insight into biochemical consequences of transformation and are candidate biomarkers of ovarian oncogenesis. Validation studies are warranted to determine whether these compounds have clinical utility in the diagnosis or clinical management of ovarian cancer patients

Typical auditory-motor and enhanced visual-motor temporal synchronization in adults with Autism Spectrum Disorder

The perception of subsecond durations in adults with Autism Spectrum Disorder (hereafter ‘autism’; n=25 Experiment 1, n=21 Experiment 2) and matched typical adults (n=24 Experiment 1, n=22 Experiment 2) was examined by requiring participants to perform an action in time with auditory (Experiment 1) or visual (Experiment 2) events. Individuals with autism performed comparably to typical participants in the auditory task and exhibited less temporal error relative to their typical counterparts in the visual task. These findings suggest that perception of subsecond intervals is intact in autism, if not enhanced. Results support recent Bayesian theories of enhanced visual-perceptual precision in people with autism, and extend empirical support into the precision of subsecond temporal estimates