Wania F.,University of Toronto |
Lei Y.D.,University of Toronto |
Wang C.,University of Toronto |
Abbatt J.P.D.,University of Toronto |
And 2 more authors.
Atmospheric Chemistry and Physics | Year: 2015
Many atmospheric and chemical variables influence the partitioning equilibrium between gas phase and condensed phases of compounds implicated in the formation of secondary organic aerosol (SOA). The large number of factors and their interaction makes it often difficult to assess their relative importance and concerted impact. Here we introduce a two-dimensional space which maps regions of dominant atmospheric phase distribution within a coordinate system defined by equilibrium partition coefficients between the gas phase, an aqueous phase and a water-insoluble organic matter (WIOM) phase. Placing compounds formed from the oxidation of n-alkanes, terpenes and mono-aromatic hydrocarbons on the maps based on their predicted partitioning properties allows for a simple graphical assessment of their equilibrium phase distribution behaviour. Specifically, it allows for the simultaneous visualisation and quantitative comparison of the impact on phase distribution of changes in atmospheric parameters (such as temperature, salinity, WIOM-phase polarity, organic aerosol load, and liquid water content) and chemical properties (such as oxidation state, molecular size, functionalisation, and dimerisation). The graphical analysis reveals that the addition of hydroxyl, carbonyl and carboxyl groups increases the affinity of aliphatic, alicyclic and aromatic hydrocarbons for the aqueous phase more rapidly than their affinity for WIOM, suggesting that the aqueous phase may often be relevant even for substances that are considerably larger than the C2 and C3 compounds that are typically believed to be associated with aqueous SOA. In particular, the maps identify some compounds that contribute to SOA formation if partitioning to both WIOM and aqueous phase is considered but would remain in the gas phase if either condensed phase were neglected. For example, many semi-volatile Î±-pinene oxidation products will contribute to aqueous SOA under the conditions of high liquid water content encountered in clouds but would remain vapours in wet aerosol. It is conceivable to develop parameterisations of "partitioning basis sets" that group compounds with comparable partitioning properties, which-when combined with data on the abundance of those groups of compounds-could serve in the simulation of SOA formation. © 2015 Author(s).
Wahyuningsih S.,Kampus IPB Dramaga |
Effendi H.,Center for Environmental Research |
Wardiatno Y.,Kampus IPB Dramaga
AACL Bioflux | Year: 2015
Nitrogen wastes in the culture system are still difficult to handle. Aquaponic system can be an alternative to reduce the impact of the inorganic nitrogen accumulation that can be a limiting factor to the fish growth. At aquaponic system plant can absorb nutrient from farming waste, whereas bacteria functions in reducing the ammonia through the nitrification process. The aim of study was to assess aquaculture nitrogen waste reduction in aquaponic system. The result showed that the nutrient concentration fluctuated during the observation periods, and the highest nutrients accumulation were 6.489, 3.601, and 0.933 mg L-1 for TAN (ammonia and ammonium), nitrate, and nitrite in the control, respectively. Integration of tilapia (Oreochromis niloticus) fish farming, romaine lettuce (Lactuca sativa), and bacteria can reduce inorganic nitrogen with the best removal efficiency. There was 91.50, 34.41, 22.86, and 49.74% for TAN, nitrate, and nitrite, respectively. All results showed that treatment with the bacteria addition was the best treatment to reduce nitrogen waste, optimizing the fish and romaine lettuce plants production. © 2015, BIOFLUX SRL. All rights resereved.
Esther A.,University of Potsdam |
Esther A.,Federal Research Center for Cultivated Plants |
Groeneveld J.,Center for Environmental Research |
Groeneveld J.,University of Auckland |
And 7 more authors.
Journal of Vegetation Science | Year: 2010
Question: The majority of studies investigating the impact of climate change on local plant communities ignores changes in regional processes, such as immigration from the regional seed pool. Here we explore: (i) the potential impact of climate change on composition of the regional seed pool, (ii) the influence of changes in climate and in the regional seed pool on local community structure, and (iii) the combinations of life history traits, i.e. plant functional types (PFTs), that are most affected by environmental changes. Location: Fire-prone, Mediterranean-type shrublands in southwestern Australia. Methods: Spatially explicit simulation experiments were conducted at the population level under different rainfall and fire regime scenarios to determine the effect of environmental change on the regional seed pool for 38 PFTs. The effects of environmental and seed immigration changes on local community dynamics were then derived from community-level experiments. Classification tree analyses were used to investigate PFT-specific vulnerabilities to climate change. Results: The classification tree analyses revealed that responses of PFTs to climate change are determined by specific trait characteristics. PFT-specific seed production and community patterns responded in a complex manner to climate change. For example, an increase in annual rainfall caused an increase in numbers of dispersed seeds for some PFTs, but decreased PFT diversity in the community. Conversely, a simulated decrease in rainfall reduced the number of dispersed seeds and diversity of PFTs. Conclusions: PFT interactions and regional processes must be considered when assessing how local community structure will be affected by environmental change. © 2010 International Association for Vegetation Science.
Norouzi P.,University of Tehran |
Rashedi H.,University of Tehran |
Alipour A.,University of Tehran |
Faridbod F.,Tehran University of Medical Sciences |
And 2 more authors.
International Journal of Electrochemical Science | Year: 2011
Flurazepam is a benzodiazepine derivative which possesses anxiolytic, anticonvulsant, sedative and skeletal muscle relaxant properties. This research introduces two kinds of PVC membrane sensor (symmetric and asymmetric) for determination of flurazepam (FLZ) in pharmaceutical formulation. For the membrane preparation, flurazepam-tetraphenyl borate ion-pair was employed as a sensing material in the PVC membrane. Several plasticizers were studied in the membrane composition dibutyl phthalate (DBP), acetophenon (AP), nitrobenzene (NB) and nitrophenyloctyl ether (o-NPOE). After a series of experiments, the best electrode performance was made of a membrane composed of DBP. The electrodes illustrated a fast, stable and Nernstian response over a wide flurazepam concentration range of 1×10-5 to 1×10-2 M in case of PVC membrane electrode and 1×10-6 to 1×10-3 M in case of wire coated electrode, in the pH range of 4.0-7.0. Validation of the method shows suitability of the sensors for use in the analysis of flurazepam hydrochloride in pharmaceutical formulation. © 2011 by ESG.
Ost M.,Novia University of Applied Sciences |
Lehikoinen A.,University of Helsinki |
Jaatinen K.,Novia University of Applied Sciences |
Kilpi M.,Center for Environmental Research
Oecologia | Year: 2011
The potentially confounded effects of factors affecting breeding dispersal have rarely been simultaneously examined. The consequences of breeding dispersal are even less studied, presenting a paradox: breeding dispersal seldom seems to improve breeding success, despite its presumed adaptiveness. We studied the causes and consequences of breeding dispersal in female-philopatric eiders (Somateria mollissima) in relation to the spatiotemporal predictability of nest success. Previous nest fate, breeding experience, and breeding density simultaneously affected breeding dispersal. Dispersal distances were longer among inexperienced breeders and after failed breeding. Individual dispersal distances decreased with increasing nest-site-specific breeding density, whereas island-specific nesting success peaked at intermediate densities. The fate of neighbouring nests ('public information') did not influence dispersal. Breeding dispersal was unrelated to subsequent hatching success, controlling for individual quality (body condition, breeding experience, previous nest fate), while it delayed hatch date, which is likely to impair reproductive success. This delay may result from the loss of acquired information of local breeding conditions, prolonging nest prospecting and establishment, also helping explain why breeding dispersal did not increase at high breeding densities, despite a potential reduction in nesting success. In long-lived species, however, dispersal-induced reductions in reproductive output in one season could be offset by improved parental survival prospects. Careful nest prospecting may be profitable, because overall nest success had a strong island-specific component but showed weak temporal variation, and successive individual nest fates were predictable between years. Once a safe nest site is found, females may breed at the same place successfully for many years. © 2010 Springer-Verlag.