Search results for "Sources"
showing 10 items of 2554 documents
La holografía como recurso didáctico para la enseñanza de contenidos de geometría en primaria
2021
En el presente artículo se analizarán los usos y beneficios que reportaría trabajar con hologramas como material didáctico, como así demuestran los estudios de Ghuloum, Escrivà y Orcos. A través de estas propuestas didácticas se refuerza la idea de que el uso de la técnica de representación en tres dimensiones puede beneficiar al alumnado en la adquisición de los contenidos geométricos presentes en el currículum oficial. El ámbito de la geometría ofrece una amplia gama de contenidos que posibilitan trabajar mediante técnicas de representación gráfica. Cabe destacar, por otra parte, que ahora los estudiantes de educación primaria están socializados en el acceso y uso de imágenes de todo tipo…
The effect of using a mobile literacy game to improve literacy levels of grade one students in Zambian schools
2014
This intervention study was conducted to document conditions under which a computer based literacy game (GraphoGame™) could enhance literacy skills of first grade students in an African city. The participants were first grade students from Government schools (N = 573). These students were randomly sampled into control (N = 314) and various intervention groups (N = 259). GraphoGame™ was administered on cellphones to students at their schools under supervision. Each student in the study was assessed using a battery of locally developed cognitive tests that measured emergent literacy skills (Orthography test), decoding competence (Spelling test), vocabulary (Picture Vocabulary Test—PVT) and ar…
Manure as a potential source of renewable energy: The behaviour and characterisation of biofuels generated from three animal manure types when subjec…
2020
Regions with high livestock density lack sufficient land on which to apply manure without exceeding the legal limits set by the European Union Directives. The lack of manure processing alternatives aggravates the situation, especially in the case of islands. Consequently, manure becomes a liability rather than an asset. Results indicate that pyrolysis is an option for manure processing. However, a significant limitation is the moisture content of the starting material, that could compromise the process efficiency. Yields of biogas, bio-oil and biochar, all of which have a potential use as biofuels, are particular to animal type and manure handling system. The conversion of manure to biofuel…
The state of water resources in major mediterranean islands
2014
This work analyses the state of water resources in six Mediterranean islands: Corsica, Crete, Cyprus, Mallorca, Malta and Sicily. The analysis is focused on the prevailing social, economic and hydroclimatological characteristics of these islands in order to identify the main common features affecting water availability, demand and use. A detailed analysis of the state of water resources in all the considered islands has been carried out. A background of current conditions relating to freshwater availability, quality and use has been established. Different strategies to face water scarcity and enhance water quality in theislands have been assessed in a context of climate change which is a co…
Evaluating the Efficiency of Water Distribution Network Sectors Using the DEA-Weight Russell Directional Distance Model: The Case of the City of Vale…
2021
In many cities, sectorization projects of the drinking water distribution network have been implemented. This study provides a methodology to evaluate the efficiency of the sectors of a water distribution network by applying a data envelopment analysis weighted Russell directional distance (DEA-WRDD) model. This non-radial DEA model gives the overall efficiency of each unit of analysis, as well as each input, output, and undesirable output considered in the evaluation. The variables used in the analysis provide a multidisciplinary view: economic factors (covering costs), water quality parameters, and technical aspects. The empirical analysis was performed for the sectors of the water distri…
Assessing impacts of soil management measures on ecosystem services
2018
Only a few studies have quantified and measured ecosystem services (ES) specifically related to soil. To address this gap, we have developed and applied a methodology to assess changes in ecosystem services, based on measured or estimated soil property changes that were stimulated by soil management measures (e.g., mulching, terracing, no-till). We applied the ES assessment methodology in 16 case study sites across Europe representing a high diversity of soil threats and land use systems. Various prevention and remediation measures were trialled, and the changes in manageable soil and other natural capital properties were measured and quantified. An Excel tool facilitated data collection, c…
The role of soils in regulation and provision of blue and green water
2021
The United Nations Sustainable Development Goal 6 aims for clean water and sanitation for all by 2030, through eight subgoals dealing with four themes: (i) water quantity and availability, (ii) water quality, (iii) finding sustainable solutions and (iv) policy and governance. In this opinion paper, we assess how soils and associated land and water management can help achieve this goal, considering soils at two scales: local soil health and healthy landscapes. The merging of these two viewpoints shows the interlinked importance of the two scales. Soil health reflects the capacity of a soil to provide ecosystem services at a specific location, taking into account local climate and soil condit…
Adding the Mureş River Basin (Transylvania, Romania) to the List of Hotspots with High Contamination with Pharmaceuticals
2020
Background: The Mureș River Basin is a long-term heavily polluted watershed, in a situation of climate changes with increasing water flow and related decreasing dilution capacity. Here, a mixture of emerging pollutants such as pharmaceuticals were targeted to reveal potential risks regarding the natural lotic ecosystems. Due to the continuous discharge into the environment, pharmaceuticals are gaining persistent organic pollutant characteristics and are considered emerging pollutants. Based on the hazard quotient, this research highlights the dangerous concentrations of carbamazepine, ibuprofen, furosemide, and enalapril in river water. Results: High levels of four pharmaceutical compounds …
Remote sensing of cyanobacterial blooms in a hypertrophic lagoon (Albufera of València, Eastern Iberian Peninsula) using multitemporal Sentinel-2 ima…
2018
Eutrophy in Albufera of Valencia (Eastern Iberian Peninsula) is a quite old problem since after the intense eutrophication processes throughout the 1960s. The system shifted to a turbid stable state consolidated by the virtual disappearance of macrophytes by the early 1970s. The lagoon has been studied extensively since the 1980s, but efforts to revert the system to a clear state have not yielded the expected results because cultural eutrophication due to the growth of population in its area of influence and the effects of climate change, decreasing rainfall and increasing evaporation. This has driven to an increase in water retention times in the lagoon in recent years, resulting in a phyt…
A mathematical model for wastewater modification processes assessment in a stabilization reservoir
2012
The paper presents a mathematical model for the simulation of the ecological status of a wastewater stabilization reservoir (WSR). WSRs are hypertrophic aquatic systems devoted to storage of water resources in warm countries where shortage conditions have quite often to be faced. Several factors that affect the stabilization reservoir effluent quality were taken into account: hydraulics and hydrology, solar radiation, atmospheric reaeration, algae, zooplankton, organic matter, pathogen bacteria, and sediment-water interaction. The model quantifies the specific influence of each factor on effluent quality, evaluating the correlation between the different considered factors. State variables i…