Search results for " quality."
showing 10 items of 2995 documents
Modulation transfer function in refractive-diffractive multifocal intraocular lenses in vitro
2007
Purpose: The optical quality of two types of multifocal, hybrid refractive-diffractive, intraocular lenses (IOL) is analyzed in vitro. Following the EN-ISO international standard, the IOLs’ modulation transfer functions (MTF) are determined for both distance and near vision. The behaviour of these curves when the pupil size varies is studied. Methods: The IOLs analyzed were: AcrySoft ResTor SN60D3 (Alcon) and Tecnis ZM900 (AMO). The MTF was calculated from the cross line-spread function recorded with the OPAL Vector System (Image Science Ltd. Oxford) by using fast Fourier transform techniques. The artificial eye model used simulates in vivo conditions of the anterior chamber including an ar…
Uncertainty in urban stormwater quality modelling: The effect of acceptability threshold in the GLUE methodology
2007
Uncertainty analysis in integrated urban drainage modelling is of growing importance in the field of water quality. However, only few studies deal with uncertainty quantification in urban drainage modelling; furthermore, the few existing studies mainly focus on quantitative sewer flow modelling rather than uncertainty in water quality aspects. In this context, the generalised likelihood uncertainty estimation (GLUE) methodology was applied for the evaluation of the uncertainty of an integrated urban drainage model and some of its subjective hypotheses have been explored. More specifically, the influence of the subjective choice of the acceptability threshold has been detected in order to ga…
The role of eutrophication reduction of two small man-made Mediterranean lagoons in the context of a broader remediation system: Effects on water qua…
2013
In order to meet the requirements of the European Union Water Framework Directive for the Albufera de Valencia (AV) Natural Park, in 2009, several areas of free water surface constructed wetlands (FWSCWs) planted with emergent vegetation and two small shallow lagoons planted with submerged macrophytes were created over a 40-ha area formerly occupied by rice fields. This area is currently a reserve known as Tancat de la Pipa. The dual goal of this programme was to improve the quality of the hyper-eutrophicated waters of the AV lagoon, the largest littoral lagoon in the Iberian Peninsula, and to restore former lost habitats to increase the biodiversity of the area. The lagoons were mainly fed…
A Soil Water Assessment Tool (SWAT) Modeling Approach to Prioritize Soil Conservation Management in River Basin Critical Areas Coupled With Future Cl…
2021
About 44% of the Indian landmass experiences the adverse impact of land degradation. This loss of sediments caused by soil erosion reduces the water quality of local water bodies and decreases agricultural land productivity. Therefore, decision-makers must formulate policies and management practices for sustainable management of basins that are cost-effective and environment friendly. Application of the best management practices (BMPs) to properly manage river basins is difficult and time-consuming. Its implication under various climate change scenarios makes it more complicated but necessary to achieve sustainable development. In this study, the soil and water assessment tool (SWAT) model…
Structural variables drive the distribution of the sensitive lichen Lobaria pulmonaria in Mediterranean old-growth forests
2015
a b s t r a c t We tested the hypothesis that structural variables related to old-growth features affect the distribution of Lobaria pulmonaria in a Mediterranean National Park of Italy. A total of 36 plots, with old-growth characteristics and representing overall three forest types (beech- oak- and mixed- forests) were studied. The lichen was absent in about half of the sites, suggesting that the selection of old-growth forests based solely on structural features is not sufficient to predict the presence of this species, which therefore proves to be rather sensitive and selective. Its abundance was related to high tree circumference and basal area, and to availability of deadwood, confirmi…
Geochemistry and potential use of groundwater in the Rocca Busambra area (Sicily, Italy)
2008
In the Rocca Busambra area (mid-west Sicily, Italy), from November 1999 to July 2002, 23 water points including wells and springs were sampled and studied for their chemical and isotopic compositions. Two rain gauges were also installed at different altitudes, and rainwater was collected monthly to determine the isotopic composition. The obtained results revealed the Rocca Busambra carbonate complex as being the main recharge area on account of its high permeability value. From a chemical view point, two main groups of water can be distinguished: calcium–magnesium–bicarbonate-type and calcium–magnesium–chloride–sulphate-type waters. The first group reflects the dissolution of the carbonate …
Persentase Tutupan Terumbu Karang di Perairan Pasir Putih Kabupaten Manokwari
2017
Penelitian ini dilakukan pada bulan Oktober sampai November 2014 di perairan Pasir Putih Kabupaten Manokwari, berlokasi di Pantai Air Salobar. Tujuan penelitian adalah untuk mengetahui persentase tutupan terumbu karang, kualitas fisik-kimia air dan korelasi kualitas fisik-kimia air terhadap persentase tutupan terumbu karang di bagian barat daya perairan Pasir Putih, Manokwari. Metode yang digunakan untuk memperoleh data persentase tutupan karang adalah Point Intercept Transect (PIT) pada kedalaman 3 m (Transek I), 7 m (Transek II) dan 10 m (Transek III). Hasil pengamatan diperoleh persentase tutupan karang pada Transek I adalah 91%, Transek II adalah 78% dan Transek III adalah 54%. Kondisi …
Modelling groundwater processes in a carbonate catchment: a case study from the Madonie area (Northern Sicily)
2011
Abstract This study reports on the results of a hydrogeochemical survey carried out in the Madonie area, a carbonate massif located in Palermo Province, Northern Sicily. The large dataset (226 collected sites) is used to highlight the processes controlling the distribution of dissolved chemicals in groundwaters; and, more importantly, to develop a general model (based on reaction-path modelling, and using the EQ3/6 code) of rock–water reactions in a carbonate environment. The investigated groundwater samples have conductivity between 31.7 and 8220 μS/cm; their total dissolved solids (TDS) content is higher near the coast area, where the seawater contribution becomes important. Calcium and H…
Comparing Physical Quality of Forest and Pasture Soils in a Sicilian Watershed
2011
Forest and pasture soils should have differing properties due, for example, to differing root characteristics or livestock trampling rates, but contradictory results are reported in the literature. The surface soil physical and hydraulic properties of five forest and pasture sites were determined in a Sicilian watershed. In general, forest soils had a significantly lower bulk density, b (by 17 to 35%), and a higher field saturated hydraulic conductivity, Kfs (by a factor of 3.4-11.5) than pasture soils. Differences between water retention characteristics of forest and pasture soils were low when high levels of organic matter, OM, content (> 7.1%) were detected for both land uses. The mean …
Environmental and spatial correlates of community composition, richness and status of boreal lake macrophytes
2013
Abstract We assessed the relative roles of natural covariates, human disturbance (water quality and catchment land use) together with geography in driving variation in aquatic macrophyte community composition, richness and status among 101 lakes in southern and central Finland. In addition to all species together, we studied different growth forms (i.e. emergent and submerged macrophytes and aquatic bryophytes) separately. Partial redundancy analysis (taxonomic composition) and partial least-squares regression (species richness and status index) were employed to display the share of variability in macrophyte assemblages that was attributable to the environmental factors (both natural and hu…