2,456 research outputs found

    Biodiversity monitoring in wastewater oxidation ponds

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    In order to study the relationship between Wastewater Oxidation Ponds efficiency and maturation ponds ecological communities, two AGERE systems from Braga neighbouring villages were selected: Cabreiros, CAB and Tebosa, TEB. Every two weeks sampling campaigns were realized (March - July 2007) to gather wastewater simple samples at the systems inflow and outflow. Determinations of Biochemical and Chemical Oxygen Demand and Total Suspended Solids (BOD5, COD and TSS mg/L), Recovered Heterotrophics and Total and Fecal Coliforms (RH, TC and FC, CFU ml/L) were performed at UM-Biology Lab. The removal efficiencies were 10% higher at CAB for BOD5 and COD and 10% higher at TEB for TSS. RH removal was mostly higher than 95%, but on CAB 6 and 9 samples, was respectively null and weak. During almost all the sampling period TC and FC removal were about 100% at both systems, but on samples 6 and 9, TC and FC CFU/ml were higher at CAB outflow than at inflow. Samples from maturation ponds were also gathered and maintained in the lab for a month, as microcosms. The daily microscopic analysis showed that in CAB maturation pond Euglena, Scenedesmus and diatoms are generally predominant whereas in TEB maturation pond the constant presence of Lemna was concomitant with a lesser density and diversity of algae. The samples 6 and 9 from CAB maturation pond, showed an absence of eucaryotic heterotrophics probably associated with the weak or even null removal of TC and FC

    Turbulence Model Effects on RANS Simulations of the HIFiRE Flight 2 Ground Test Configurations

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    The Wind-US Reynolds-averaged Navier-Stokes solver was applied to the Hypersonic International Flight Research Experimentation (HIFiRE) Flight 2 scramjet ground test configuration. Two test points corresponding to flight Mach numbers of 5.9 and 8.9 were examined. The emphasis was examining turbulence model effects on the prediction of flow path pressures. Three variants of the Menter k-omega turbulence model family were investigated. These include the baseline (BSL) and shear stress transport (SST) as well as a modified SST model where the shear stress limiter was altered. Variations in the turbulent Schmidt number were also considered. Choice of turbulence model had a substantial effect on prediction of the flow path pressures. The BSL model produced the highest pressures and the SST model produced the lowest pressures. As expected, the settings for the turbulent Schmidt number also had significant effects on predicted pressures. Small values for the turbulent Schmidt number enabled more rapid mass transfer, faster combustion, and in turn higher flowpath pressures. Optimal settings for turbulence model and turbulent Schmidt number were found to be rather case dependent, as has been concluded in other scramjet investigations

    Group-level differences in social network structure remain repeatable after accounting for environmental drivers

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    Individuals show consistent between-individual behavioural variation when they interact with conspecifics or heterospecifics. Such patterns might underlie emergent group-specific behavioural patterns and between-group behavioural differences. However, little is known about (i) how social and non-social drivers (external drivers) shape group-level social structures and (ii) whether animal groups show consistent between-group differences in social structure after accounting for external drivers. We used automated tracking to quantify daily social interactions and association networks in 12 colonies of zebra finches (Taeniopygia guttata). We quantified the effects of five external drivers (group size, group composition, ecological factors, physical environments and methodological differences) on daily interaction and association networks and tested whether colonies expressed consistent differences in day-to-day network structure after controlling for these drivers. Overall, we found that external drivers contribute significantly to network structure. However, even after accounting for the contribution of external drivers, there remained significant support for consistent between-group differences in both interaction (repeatability R: up to 0.493) and association (repeatability R : up to 0.736) network structures. Our study demonstrates how group-level differences in social behaviour can be partitioned into different drivers of variation, with consistent contributions from both social and non-social factors

    Effect of ozone and antioxidants on wheat and its pathogen — Bipolaris sorokininana

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    Tropospheric ozone (O3) adversely affects growth and productivity of crops and also influences crop—pathogen interactions. Adverse effects of O3 on crops can be mitigated by antioxidants application. In the present study through lab and field experiments impact of O3 and antioxidants treatment to wheat was assessed on growth of Bipolaris sorokiniana (BS-75 strain) pathogen responsible for Spot blotch disease, pathogenesis related (PR) proteins and chitinase content. Results showed that growth of Bipolaris was significantly higher in elevated ozone (EO3) exposed plants as compared to control plants. Antioxidants — ascorbic acid (AA), tagetes extract (T) and quercetin (Q) application on culture media and wheat plants, respectively, retarded the growth of Bipolaris sorokiniana. Among the three antioxidants minimum growth of Bipolaris was observed in AA-treated plants as compared to control plants. Reduction in chitinase activity and PR proteins content due to EO3 treatment in wheat plants was 18% and 78%, respectively, as compared to control plants. Increase in chitinase activity and PR proteins content due to antioxidants treatment in wheat plants was 45% and 60%, respectively, as compared to control plants
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