Search results for "Conservation"
showing 10 items of 2328 documents
A simulation/optimization model for selecting infrastructure alternatives in complex water resource systems
2010
The paper introduces a simulation/optimization procedure for the assessment and the selection of infrastructure alternatives in a complex water resources system, i.e. in a multisource (reservoirs) multipurpose bulk water supply scheme. An infrastucture alternative is here a vector X of n decision variables describing the candidate expansions/new plants/water transfers etc. Each parameter may take on a discrete number of values, with its own investment cost attached. The procedure uses genetic algorithms for the search of the optimal vector X through operators mimicking the mechanisms of natural selection. For each X, the value of the objective function (O.F.) is assessed via a simulation mo…
Representation of capacity drop at a road merge via point constraints in a first order traffic model
2018
We reproduce the capacity drop phenomenon at a road merge by implementing a non-local point constraint at the junction in a first order traffic model. We call capacity drop the situation in which the outflow through the junction is lower than the receiving capacity of the outgoing road, as too many vehicles trying to access the junction from the incoming roads hinder each other. In this paper, we first construct an enhanced version of the locally constrained model introduced by Haut et al. (Proceedings 16th IFAC World Congress. Prague, Czech Republic 229 (2005) TuM01TP/3), then we propose its counterpart featuring a non-local constraint and finally we compare numerically the two models by c…
Historischer Überblick zur mathematischen Theorie von Unstetigkeitswellen seit Riemann und Christoffel
1981
We give a brief historical account of the development of the mathematical theory of propagation of discontinuities in gases, fluids or elastic materials. The theory was initiated by Riemann who investigated the propagation of shocks in one-dimensional isentropic gas flow. Riemann’s results were used by Christoffel to treat, more generally, the propagation of (first order) discontinuity surfaces in three-dimensional flows of perfect fluids. Subsequently Christoffel applied his general theory to first order waves in certain elastic materials. Independently of Riemann and Christoffel significant contributions were made by Hugoniot. The theory was completed in Hadamard’s celebrated monograph [3…
Distances, espaces et représentations (une revue)
1990
L'objet de cet article est de donner un aperçu de la manière dont la littérature traite ce rapport entre la forme de la distance et les propriétés de l'espace. Il existe un grand nombre de travaux dans ce domaine et, malgré le volume de ce texte, nous ne pouvons en rendre compte complètement. La section 1 présente les formes de distances les plus connues et montre les déformations qu'elles impliquent par rapport à l'espace réel, observé, ainsi que par rapport à sa représentation la plus commune: l'espace euclidien muni d'une distance euclidienne. La section 2 porte le débat au niveau des modèles de l'économie spatiale. Il y a plusieurs façons de modéliser une même réalité: la représentation…
Characterization of Maya Blue Pigment in Pre-Classic and Classic Monumental Architecture of the Ancient Pre-Culombian City of Calakmul (Campeche, Mex…
2011
This paper presents the first evidence of the use of Maya Blue pigment in late pre-classic (c.300BC-300AD) architecture in the Maya Lowlands. This was detected combining an innovative technique, the voltammetry of microparticles (VMP), with atomic force microscopy (AFM), transmission electron microscopy (TEM), scanning electron microscopy/energy dispersive X-ray microanalysis (SEM/EDX), visible spectrophotometry and Fourier transform infrared spectroscopy (FTIR). The pigment was found on the polychrome facade of substructure IIC of pre-Columbian city of Calakmul (Campeche, Mexico). The identification of Maya Blue in this building may prove to be the earliest known use of this colour on the …
The last meal: large insects predominate the diet of the European Roller Coracias garrulus prior to population extinction
2019
Capsule: The diet of a European Roller Coracias garrulus population, approximately 10 years before its extinction, comprised of large-bodied orthopterans and coleopterans. Aims: To explore the diet composition of declining population of the European Roller. Methods: In 2005, 2006 and 2009, we monitored 18 nesting sites of the European Roller in southern Poland. Pellets and prey remain found in nest-holes were analysed. Results: In total, 1646 prey items were found. Orthoptera (60.4% of prey items) and Coleoptera (38.5%) predominated while vertebrates were caught rarely. Large-bodied species (orthopterans, bush-crickets, beetles Prionus coriarius and Cetonia aurata) including ground-dwellers…
Geoscience Teaching and Student Interest in Secondary Schools-Preliminary Results from an Interest Research in Greece, Spain and Italy.
2013
The results of a topic-interest study on geosciences among 14- to 17-year-old school students are reported. The research was organized in the framework of the European project Geoschools to investigate the interest of students in the context of teaching strategies for geosciences in secondary schools. A questionnaire was designed as the main data-collection tool, based on the results of a comparison on geosciences curricula among the five European countries (Austria, Greece, Portugal, Italy, and Spain) which are the partners in the GEOschools project. The present study focuses on results from Greece and Spain but also includes preliminary results from Italy, for comparison purposes. Questio…
Biodiversity conservation and protected areas in the Mediterranean region
2018
This chapter provides an overview of current biodiversity knowledge in Mediterranean forest ecosystems across all levels (genetic diversity, species diversity, landscape diversity) and endemism, ecological peculiarities that make Mediterranean forest ecosystems different. It also outlines the importance of biodiversity for functional forest ecosystems and illustrates some examples of conservation efforts in the region.
Aridity index, soil erosion and climate drive no-till ecosystem services trade-off in Mediterranean arable land
2021
Abstract Despite the relevant literature on the advantages of no-till (NT) management, the world area under NT is only 10% of the arable land, probably due to several limiting factors as climate, soil types, farming systems and yield. Soil conservation practices and particularly NT soil management are able to provide many ecosystem services (ESs). This paper suggests a framework to determine the area distribution of soil erosion control and food security ESs trade-offs furnished by NT, starting from the potential soil erosion and aridity index maps. The interaction between the potential soil erosion and the aridity index showed that different trade-offs and synergies of multiple ESs may occ…
Chlorine as a Discriminant Element to Establish the Provenance of Central Mediterranean Obsidians
2020
Abstract Chlorine is a minor element present in obsidians in quantities greater than in average igneous rocks. The chlorine concentration in obsidians is generally low, of the order of tenths of wt %, but it exhibits an appreciable differentiation among geological sources. Despite these characteristics, chlorine has rarely been taken into consideration as a possible indicator of obsidian provenance and it does not appear in the chemical analytical tables accompanying the geochemical characterisation of obsidian samples. In this work, after an overview of chlorine geochemistry and cycle, we present thirty-one new electron microprobe (EPMA) analyses, including Cl, of geologic obsidians sample…