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National level Ecological Footprint studies have highlighted disparities among countries. This assessment has proved essential to accurately characterize ecological impacts to specific countries but often ignore the het-erogeneity...
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National level Ecological Footprint studies have highlighted disparities among countries. This assessment has proved essential to accurately characterize ecological impacts to specific countries but often ignore the het-erogeneity within national spaces. Population groups within a country engage in different behaviors and con-sumption patterns that have a distinct impact on the environment. Understanding the contribution of each group and decomposing their consumption of distinct products is critical to helping environmental organizations and policy makers design more efficient policies and communication strategies that will change critical patterns of human demand. In the current study, national household consumption is split into different population groups corresponding to four particular socio-economic dimensions: main sources of income, age, number of members in the household, and levels of education of the population. The aim is to identify critical groups to provide better ground to generate targeted policies that can achieve better environmental results. Results highlight how diverse ecological impacts can occur among distinct population groups, with the highest per capita Footprint values found in households with higher education level, smaller size and those living from Capital/Property Transfers. These results constitute a new possibility to analyze the impact of policies that tackle specific behaviors of distinct population groups.
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Wetlands are critically important for biodiversity and human wellbeing, but face a range of challenges. This is especially true in the Mediterranean region, where wetlands support endemic and threatened species and remain integral...
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Wetlands are critically important for biodiversity and human wellbeing, but face a range of challenges. This is especially true in the Mediterranean region, where wetlands support endemic and threatened species and remain integral to human societies, but have been severely degraded in recent decades. Here, in order to raise awareness of future challenges and opportunities for Mediterranean wetlands, and to inform proactive research and management, we identified (a) 50 key issues that might affect Mediterranean wetlands between 2020 and 2050, and (b) 50 important research questions that, if answered, would have the greatest impact on the conservation of Mediterranean wetlands between 2020 and 2050. We gathered ideas through an online survey and review of recent literature. A diverse assessment panel prioritised ideas through an iterative, anonymised, Delphi-like process of scoring, voting and discussion. The prioritised issues included some that are already well known but likely to have a large impact on Mediterranean wetlands in the next 30 years (e.g. the accumulation of dams and reservoirs, plastic pollution and weak governance), and some that are currently overlooked in the context of Mediterranean wetlands (e.g. increasing desalination capacity and development of antimicrobial resistance). Questions largely focused on how best to carry out conservation interventions, or understanding the impacts of threats to inform conservation decision-making. This analysis will support research, policy and practice related to environmental conservation and sustainable development in the Mediterranean, and provides a model for similar analyses elsewhere in the world.
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Seafood is central to the diet of Mediterranean inhabitants. However, there is high consumer demand for certain species whose populations are rapidly declining in the Mediterranean Sea. Diversifying regional seafood preferences ha...
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Seafood is central to the diet of Mediterranean inhabitants. However, there is high consumer demand for certain species whose populations are rapidly declining in the Mediterranean Sea. Diversifying regional seafood preferences has the potential to reduce pressure on marine ecosystems while supporting local fishing economies. Here, we explored this opportunity through case studies in three Mediterranean countries: Croatia, Italy, and Turkey. First, we conducted an Ecological Footprint Analysis (EFA) to quantify the environmental impact of each country's food consumption choices. Then, we distributed a seafood consumer survey to understand each country's dietary preferences and residents' overall willingness to change their diets, with a specific focus on products from Small-Scale Fisheries (SSF). We found food consumption to be the primary Ecological Footprint driver in all three countries, with a contribution from the consumption of fish and seafood ranging from 6% (Turkey) to 11% (Italy) of each country's food Footprint. Results from the consumer survey showed that dietary preferences were unique to each culture. For example, consumers in Italy and Turkey were more willing to modify their diets than residents surveyed in Croatia. Across all three countries, consumers who are more aware of product labels, origin, and freshness of seafood products were more willing to purchase diverse seafood products. To diversify seafood consumption choices, particularly away from high trophic level species, consumer awareness campaigns should be tailored to meet the preferences of each unique culture in the Mediterranean. A broader Pan-Mediterranean study of culturally-unique consumer attitudes is warranted to accelerate progress towards sustainable seafood consumption in the region that benefits both biodiversity and local fishing economies.
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An efficient mixed-potential integral equation formulation is proposed for the analysis of one-dimensional (1-D) periodic leaky-wave antennas (LWAs) based on planar stratified configurations with inclusions of arbitrarily oriented...
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An efficient mixed-potential integral equation formulation is proposed for the analysis of one-dimensional (1-D) periodic leaky-wave antennas (LWAs) based on planar stratified configurations with inclusions of arbitrarily oriented metallic or dielectric perturbations. Both the transverse and vertical components of the mixed-potential Green’s functions due to a 1-D phased array of dipoles in a layered medium are accelerated using suitable homogeneous-medium asymptotic extractions from the standard spectral series of Floquet harmonics. A novel acceleration procedure is applied for the computation of the vertical potentials whose extracted terms can be expressed as potentials from a 1-D phased array of half-line sources in a homogeneous medium. Their numerical calculation requires a suitable modification of the Ewald method, thus resulting in new modified spectral and spatial series, having Gaussian convergence even in the case of complex modes and improper harmonics. Numerical comparisons for the 1-D periodic potentials, both in the case of bounded and unbounded (e.g., leaky) harmonics, validate the efficiency and accuracy of the proposed acceleration technique. The method is illustrated and verified by determining the dispersion behavior of both bound and leaky modes for several LWA test cases.
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Resonant Bessel-beam launchers are low-cost, planar, miniaturized devices capable of focusing electromagnetic radiation in a very efficient way in various frequency ranges, with recent increasing interest for microwave and millime...
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Resonant Bessel-beam launchers are low-cost, planar, miniaturized devices capable of focusing electromagnetic radiation in a very efficient way in various frequency ranges, with recent increasing interest for microwave and millimeter-wave applications (i.e., 3–300 GHz). In recent years, various kinds of launchers have appeared, with different feeding mechanisms (e.g., coaxial probes, resonant slots, or loop antennas), field polarization (radial, azimuthal, and longitudinal), and manufacturing technology (axicon lenses, radial waveguides, or diffraction gratings). In this paper, we review the various features of these launchers both from a general electromagnetic background and a more specific leaky-wave interpretation. The latter allows for deriving a useful set of design rules that we here show to be applicable to any type of launcher, regardless its specific realization. Practical examples are discussed, showing a typical application of the proposed design workflow, along with a possible use of the launchers in a modern context, such as that of wireless power transfer at 90 GHz.
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Ecological Footprint and biocapacity metrics have been widely used in natural capital and ecosystem accounting, and are frequently cited in the sustainability debate. Given their potential role as metrics for environmental science...
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Ecological Footprint and biocapacity metrics have been widely used in natural capital and ecosystem accounting, and are frequently cited in the sustainability debate. Given their potential role as metrics for environmental science and policy, a critical scrutiny is needed. Moreover, these metrics remain unclear to many, are subject to criticisms, and discussion continues regarding their policy relevance. This paper aims to explain the rationale behind Ecological Footprint Accounting (EPA) and help ensure that Ecological Footprint and biocapacity results are properly interpreted and effectively used in evaluating risks and developing policy recommendations. The conclusion of this paper is that the main value-added of Ecological Footprint Accounting is highlighting trade-offs between human activities by providing both a final aggregate indicator and an accounting framework that shed light on the relationships between many of the anthropogenic drivers that contribute to ecological overshoot. (C) 2015 The Author. Published by Elsevier
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The tunable properties of nematic liquid crystals (NLC) are here exploited in a peculiar leaky waveguide with artificial magnetic conductors as the lateral walls, a bottom metal ground plane, and a homogenized metasurface on top t...
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The tunable properties of nematic liquid crystals (NLC) are here exploited in a peculiar leaky waveguide with artificial magnetic conductors as the lateral walls, a bottom metal ground plane, and a homogenized metasurface on top to obtain dynamic beamsteering at a fixed terahertz frequency. The waveguide consists of an NLC cell sandwiched between two dielectric layers. The proposed antenna system works on its transverse-magnetic leaky mode and is capable of radiating a beam that scans either by frequency or by changing the bias voltage applied across the NLC cell. The design parameters are optimized through a rigorous modal analysis of the structure, and the radiation performance is validated through full-wave simulations. The results are promising for the realization of next-generation tunable terahertz leaky-wave antennas.
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Within the Ecological Footprint methodology, the carbon Footprint component is defined as the regenerative forest capacity required to sequester the anthropogenic carbon dioxide emissions that is not absorbed by oceans. A key para...
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Within the Ecological Footprint methodology, the carbon Footprint component is defined as the regenerative forest capacity required to sequester the anthropogenic carbon dioxide emissions that is not absorbed by oceans. A key parameter of the carbon Footprint is the Average Forest Carbon Sequestration (AFCS), which is calculated from the net carbon sequestration capacity of forests ecosystems. The aim of this paper is to increase the clarity and transparency of the Ecological Footprint by reviewing the rationale and methodology behind the carbon Footprint component, and updating a key factor in its calculation, the AFCS. Multiple calculation options have been set to capture different rates of carbon sequestration depending on the degree of human management of three types of forest considered (primary forests, other naturally regenerated forests and planted forests). Carbon emissions related to forest wildfires and soil as well as harvested wood product have been included for the first time in this update of the AFCS calculation. Overall, a AFCS value range of 0.73 +/- 0.37 t C ha(-1) yr(-1) has been identified. The resulting carbon Footprint and Ecological Footprint values have then been evaluated based on this value range. Results confirm that human demand for ecosystem services is beyond the biosphere's natural capacity to provide them. (C) 2015 Elsevier Ltd. All rights reserved.
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In this work, we analyze in detail the modal properties of a graphene-based planar waveguide (GPW) in the terahertz (THz) frequency range. The structure consists of a graphene sheet placed on the top of a grounded dielectric slab....
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In this work, we analyze in detail the modal properties of a graphene-based planar waveguide (GPW) in the terahertz (THz) frequency range. The structure consists of a graphene sheet placed on the top of a grounded dielectric slab. As is known, the surface conductivity of the graphene sheet can easily be tuned with a bias voltage via electric-field effect; we show here how such a bias affects the propagation features of both TM and TE modes supported by the GPW. An extensive dispersion analysis is performed for complex modes in both guided and radiative (leaky) regimes, considering also dielectric and metal losses as well as nonlocal effects in graphene. In particular, we focus on the behavior of the fundamental leaky modes since they exhibit quite interesting radiation features for suitable values of the bias. These results are very promising for the development of reconfigurable leaky-wave Fabry-Perot cavity antennas based on graphene at THz frequencies.
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A multifed radially periodic two-dimensional leaky-wave antenna is proposed for the generation of a directional beam continuously scanning in elevation by changing the frequency, and over a discrete number of directions in azimuth...
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A multifed radially periodic two-dimensional leaky-wave antenna is proposed for the generation of a directional beam continuously scanning in elevation by changing the frequency, and over a discrete number of directions in azimuth when activating different elements of the feeding system. The structure is planar and constituted by a circular grounded dielectric slab loaded with microstrip rings, properly positioned around the sources to support the propagation of an angularly directional surface wave over a sector determined by the corresponding activated feeder. This produces a perturbation of the surface wave, resulting in the generation of a directional leaky wave over the aperture, whose complex propagation constant is described by a single fast backward spatial harmonic. The antenna radiation features are numerically investigated in conjunction with the dispersion analysis of the structure, validated through a conventional generalized-pencil-of-function approach. Full-wave simulations have been developed to design a practical feeder, which is constituted by a circular arrangement of commercial coaxial connectors. The proposed multiport antenna is validated by means of measurements performed on a microwave manufactured prototype. The design represents an attractive simple and cost-effective solution to achieve a high-gain beam scanning over the three-dimensional space, alternative to more conventional phased-array design based on cumbersome and lossy feeding networks.
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