Search results for "6(40)"
showing 10 items of 261 documents
Litter contribution to soil organic carbon in the processes of agriculture abandon
2015
The mechanisms of litter decomposition, translocation and stabilization into soil layers are fundamental processes in the functioning of the ecosystem, as they regulate the cycle of soil organic matter (SOM) and CO2 emission into the atmosphere. In this study the contribution of litters of different stages of Mediterranean secondary succession on carbon sequestration was investigated, analyzing the role of earthworms in the translocation of SOM into the soil profile. For this purpose the δ13C difference between meadow C4-C soil and C3-C litter was used in a field experiment. Four undisturbed litters of different stages of succession (45, 70, 100 and 120 since agriculture abandon) were colle…
Grassland fire effect on soil organic carbon reservoirs in a semiarid environment
2013
Abstract. The aim of this work was to investigate the effect of an experimental fire used for grassland management on soil organic carbon (SOC) stocks. The study was carried out on Hyparrhenia hirta (L.) Stapf (Hh) grassland and Ampelodesmos mauritanicus (Desf.) T. Durand & Schinz (Am) grasslands located in the north of Sicily. Soil samples were collected at 0–5 cm before and after the experimental fire, and SOC was measured. During the grassland fire, soil surface temperature was monitored. Biomass of both grasses was analysed in order to determine dry weight and its chemical composition. The results showed that SOC varied significantly with vegetation type, while it is not affecte…
Automatic concept maps generation in support of educational processes
2014
A VLE is a system where three main actors can be devised: the teacher in the role of instructional designer, the tutor, and the stu- dent. Instructional designers need easy interaction for specifying the course domain structure to the system, and for controlling how well the learning materials agree to such a structure. Tutors need tools for having a holistic perception of the evolution of single students and/or groups in the VLE during the learning process. Finally, students need self regulation in terms of controlling their learning rate, reflect on their learning strategies, and comparing with other people in the class. In this work we claim that sharing an implicit representation of the…
Intelligent Agents supporting user interactions within self regulated learning processes
2010
The paper focuses on the main advantages in the defnition and utilization of an open and modular e-learning software platform to support highly cognitive tasks performed by the main actors of the learning process. We present in detail the integration inside the platform of two intelligent agents devoted to talking with the student and to retrieving new information sources on the Web. The process is triggered as a reply to the system’s perception that the student feels discontented with the presented contents. The architecture is detailed, and some conclusions about the growth of the platform’s overall performance are expressed.
The sense of a patient: An ethnographic multi-site field study exploring the influence of manikins on nursing students' learning
2022
The purpose of this ethnographic study was to gain insight into the influence of full-body human-like manikins on nursing students’ learning. The research question that guided the study was: How do the presence and use of human-like manikins influence nursing students’ learning? Data were collected during 15 educational sessions, using different manikins for various activities. Applying cultural-historical activity theory, this study explored the use of manikins as a mediated activity. The study’s main result was the interplay of five categories. In the first category, manikin as an object, manikins were used to teach and learn technical skills. In the second category, manikin as a subject,…
Application of the CIPP model in the study of factors that promote intercultural sensitivity
2012
The present study proposes a group of factors (related to self, context and process) favouring the development of intercultural sensitivity. A social diagnosis was performed in the Spanish province of Castellón in order to identify these factors by means of a correlational study. A non-probabilistic but representative sample consisting of 995 people from 37 different countries living in this province was used. Data were collected by means of an adaptation of the scale proposed by Chen and Starosta (2000) for the assessment of intercultural sensitivity. Results showed four profiles, and their main characteristics were studied. Variables such as country of origin, gender, academic background,…
Application of the CIPP model in the study of factors that promote intercultural sensitivity
2012
The present study proposes a group of factors (related to self, context and process) favouring the development of intercultural sensitivity. A social diagnosis was performed in the Spanish province of Castellón in order to identify these factors by means of a correlational study. A non-probabilistic but representative sample consisting of 995 people from 37 different countries living in this province was used. Data were collected by means of an adaptation of the scale proposed by Chen and Starosta (2000) for the assessment of intercultural sensitivity. Results showed four profiles, and their main characteristics were studied. Variables such as country of origin, gender, academic background,…
Short-term changes in soil Munsell colour value, organic matter content and soil water repellency after a spring grassland fire in Lithuania
2014
Abstract. Fire is a natural phenomenon with important implications on soil properties. The degree of this impact depends upon fire severity, the ecosystem affected, topography of the burned area and post-fire meteorological conditions. The study of fire effects on soil properties is fundamental to understand the impacts of this disturbance on ecosystems. The aim of this work was to study the short-term effects immediately after the fire (IAF), 2, 5, 7 and 9 months after a low-severity spring boreal grassland fire on soil colour value (assessed with the Munsell colour chart), soil organic matter content (SOM) and soil water repellency (SWR) in Lithuania. Four days after the fire a 400 m2 plo…
Managing soil nitrate with cover crops and buffer strips in Sicilian vineyards
2013
When soil nitrate levels are low, plants suffer nitrogen (N) deficiency but when the levels are excessive, soil nitrates can pollute surface and subsurface waters. Strategies to reduce the nitrate pollution are necessary to reach a sustainable use of resources such as soil, water and plant. Buffer strips and cover crops can contribute to the management of soil nitrates, but little is known of their effectiveness in semiarid vineyards plantations. The research was carried out in the south coast of Sicily (Italy) to evaluate nitrate trends in a vineyard managed both conventionally and using two different cover crops (Triticum durum and Vicia sativa cover crop). A 10 m-wide buffer strip was se…
Support for a Vraconnian Stage between the Albian sensu stricto and the Cenomanian (Cretaceous System)
2008
The geological scale for the middle Cretaceous currently used throughout the world was proposed by Alcide d'Orbigny in the XIXth century between the years 1842 and 1847 and establishes the succession of stages as Albian, Cenomanian and Turonian. In 1868 Renevier proposed that a supplemental chronostratigraphic division be intercalated between the Albian and the Cenomanian: the Vraconnian stage. This term was not generally accepted and after a period when it was referred to by Breistroffer (1936) as a substage constituting the upper part of the Albian, as an equivalent of the Stoliczkaia dispar ammonite Zone, its abandonment was "recommended" by the Conference on the Lower Cretaceous held in…