Search results for "Ecological model"
showing 10 items of 322 documents
Assessment of the integrated urban water quality model complexity through identifiability analysis
2010
Urban sources of water pollution have often been cited as the primary cause of poor water quality in receiving water bodies (RWB), and recently many studies have been conducted to investigate both continuous sources, such as wastewater-treatment plant (WWTP) effluents, and intermittent sources, such as combined sewer overflows (CSOs). An urban drainage system must be considered jointly, i.e., by means of an integrated approach. However, although the benefits of an integrated approach have been widely demonstrated, several aspects have prevented its wide application, such as the scarcity of field data for not only the input and output variables but also parameters that govern intermediate st…
Chemical oxidation and reduction of hexachlorocyclohexanes: A review
2019
Abstract Lindane (γ-hexachlorocyclohexane) and its isomers (HCH) are some of the most common and most easily detected organochlorine pesticides in the environment. The widespread distribution of lindane is due to its use as an insecticide, accompanied by its persistence and bioaccumulation, whereas HCH were disposed of as waste in unmanaged landfills. Unfortunately, certain HCH (especially the most reactive ones: γ- and α-HCH) are harmful to the central nervous system and to reproductive and endocrine systems, therefore development of suitable remediation methods is needed to remove them from contaminated soil and water. This paper provides a short history of the use of lindane and a descri…
A software for the integrated design of wastewater treatment plants
1998
Abstract A software package has been developed for automated design of wastewater treatment plants. A user-friendly environment has been implemented to facilitate design tasks, allowing rapid evaluation of different alternatives as well as performing sensitivity analyses. Flexible treatment plant configurations can be established with preliminary, primary, biological and tertiary wastewater treatments, and sludge treatment units. A generalized steady-state model developed for biological processes is also included. The design process includes treatment units sizing, plant layout, hydraulic profile calculation and equipment assignment. The system capabilities for designing new plants and upgr…
Assessment of data availability influence on integrated urban drainage modelling uncertainty
2009
In urban water quality management, several models are connected and integrated for analysing the fate of pollutants from the sources in the urban catchment to the final recipient; classical problems connected with the selection and calibration of parameters are amplified by the complexity of the modelling approach increasing their uncertainty. The present paper aims at studying the influence of reductions in available data on the modelling response uncertainty with respect to the different integrated modelling outputs (both considering quantity and quality variables). At this scope, a parsimonious integrated home-made model has been used allowing for analysing the combinative effect of data…
Transforming food systems at local levels: using participatory system dynamics in an interactive manner to refine small-scale farmers’ mental models
2017
Food systems will need to undergo considerable transformation. To be better prepared for and resilient to uncertainty and disturbances in the future, resource users and managers need to further develop knowledge about the food and farming system, with its dominating feedback structures and complexities, and to test robust and integrated system-based solutions. This paper investigates how participatory system dynamics modeling can be adapted to groups at the community level with low or no formal educational background. The paper also analyses the refinement of workshop participants’ mental models as a consequence of a participatory system dynamics intervention. For this purpose, we ran two w…
Toxicity of Mining-Contaminated Lake Sediments to Lumbriculus variegatus
2021
AbstractBoreal lakes with soft water and low buffering capacity are susceptible to excess ion loading resulting from metal mining. The impact of two Finish mining sites in downstream lakes was assessed with a chronic sediment toxicity test using a laboratory-reared freshwater Lumbriculus variegatus (Oligochaeta). The test organisms were exposed to mining-contaminated natural lake sediments and hypolimnion water (HLW) or artificial freshwater (AFW) as overlying water in two independent experimental setups. In both test setups, growth and reproduction of L. variegatus were lower in sediments from the lakes receiving high amount of mining effluents from the mines nearby. In the biomining site,…
Effects of activated carbon ageing in three PCB contaminated sediments: Sorption efficiency and secondary effects on Lumbriculus variegatus.
2015
The sorption efficiency and possible secondary effects of activated carbon (AC) (o 63-200 μm) was studied with Lumbriculus variegatus in three PCB contaminated sediments applying long AC-sediment contact time (3 years). AC amendment efficiently reduced PCB bioavailability as determined with both, L. variegatus bioaccumulation test and passive samplers. However, dose related secondary effects of AC on egestion rate and biomass were observed (applied doses 0.25% and 2.5% sediment dry weight). The sorption capacity and secondary effects remained similar when the experiments were repeated after three years of AC-sediment contact time. Further, transmission electron microscopy (TEM) samples reve…
Social Ecological Model of Problem Gambling : A Cross-National Survey Study of Young People in the United States, South Korea, Spain, and Finland
2021
Problem gambling among young people is an emerging trend globally. The online environment in particular offers various possibilities for gambling engagement. This is the first cross-national survey study using the social ecological model to analyze problem gambling, especially in the online context. The study aimed to analyze how different social ecological spheres explain problem gambling. Participants were young people aged 15–25 in the United States (n = 1212), South Korea (n = 1192), Spain (n = 1212), and Finland (n = 1200). The South Oaks Gambling Screen (SOGS) instrument measured problem gambling. The regression models analyzed problem gambling with measures of intrapersonal, interper…
Individual, Family, and Environmental Correlates of Motor Competence in Young Children: Regression Model Analysis of Data Obtained from Two Motor Tes…
2020
Physical activity and motor competence (MC) have been considered to be closely related and prevent childhood obesity. The aim of the study was two-fold: to examine MC measured with two different tools in relation to individual, family, and environmental correlates and to investigate gender differences in MC. The Test of Gross Motor Development-Third Edition (TGMD-3) was administered to three- to seven-year-old children (n = 945), while the Kö
Socioecological correlates of perceived motor competence in 5- to 7-year-old Finnish children
2019
We investigated child, family, and environmental factors associated with young children's perceptions of locomotor (LM) and object control (OC) skills. The participants comprised 472 children (6.22 ± 0.63) and their parents. The children were assessed for their perception of motor competence in LM and OC skills (using the pictorial scale of Perceived Movement Skill Competence for young children), and actual motor competence (Test of Gross Motor Development 3rd edition and Körperkoordinationstest Für Kinder). Anthropometrics were calculated using the children's body mass index standard deviation scores. A parent questionnaire included questions about child factors (sex, child's independent w…