3,663 research outputs found

    The “sowing of concrete”: Peri-urban smallholder perceptions of rural–urban land change in the Central Peruvian Andes

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    AbstractPolicy makers concerned with the peri-urban interface find their greatest challenges in the rapid urban growth of developing mountain regions, since limitations caused by relief and altitude often lead to an increased competition between rural and urban land use at the valley floors. In this context, little attention has been paid to the affected agriculturalists’ perceptions of peri-urban growth—important information required for the realization of sustainable land use planning. How is the process of rural–urban land change perceived and assessed by peri-urban smallholder communities? Which are the major difficulties to be overcome? By what means are the affected people reacting and how are these adaptation strategies linked with the ongoing landscape transformations of the hinterland?By using the example of Huancayo Metropolitano, an emerging Peruvian mountain city, it is shown that rural–urban land change is intensively discussed within peri-urban smallholder groups. Although urbanization also leads to infrastructure investments by public institutions—an advantage perceived throughout the study area—the negative impacts of rural–urban land use change prevail. The perceptions’ analysis reveals that the decrease of fertile and irrigated agricultural land at the quechua valley floor is especially considered to threaten subsistence, food and income security. In order to compensate the loss of production capacities, many smallholders try to expand or intensify their land use at the suni altitudinal belt: an agro-ecological zone characterized by steep and nonirrigated slopes that can actually not be used for the year-round production of crops previously cultivated at the quechua zone

    Design of social insurance programs: theory and evidence

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    Termination Charges in the International Parcel Market: Competition and Regulation

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    There is a broad theoretical end empirical economic literature discussing the effects of termination charges on competition and retail prices. Most of this literature has focused on the telecommunications markets. Termination charges in the international parcel market have not yet received much attention in the economic literature. The aim of this paper is to fill this gap and to analyze the economics of termination charges for parcels. We find that the economics of termination charges in the international parcel market are different to termination charges in other mar-kets. Based on these findings the paper presents a number of practical solutions and potential regulatory remedies to the dilemma of termination charges in the international parcel market.International parcel market, Termination charges, Remuneration system

    Pitfalls in fMRI

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    Several different techniques allow a functional assessment of neuronal activations by magnetic resonance imaging (fMRI). The by far most influential fMRI technique is based on a local T2*-sensitive hemodynamic response to neuronal activation, also known as the blood oxygenation level dependent or BOLD effect. Consequently, the term ‘fMRI' is often used synonymously with BOLD imaging. Because interpretations of fMRI brain activation maps often appear intuitive and compelling, the reader might be tempted not to critically question the fundamental processes and assumptions. We review some essential processes and assumptions of BOLD fMRI and discuss related confounds and pitfalls in fMRI - from the underlying physiological effect, to data acquisition, data analysis and the interpretation of the results including clinical fMRI. A background framework is provided for the systematic and critical interpretation of fMRI result

    Few electron double quantum dot in an isotopically purified 28^{28}Si quantum well

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    We present a few electron double quantum dot (QD) device defined in an isotopically purified 28^{28}Si quantum well (QW). An electron mobility of 5.5⋅104cm2(Vs)−15.5 \cdot 10^4 cm^2(Vs)^{-1} is observed in the QW which is the highest mobility ever reported for a 2D electron system in 28^{28}Si. The residual concentration of 29^{29}Si nuclei in the 28^{28}Si QW is lower than 103ppm10^{3} ppm, at the verge where the hyperfine interaction is theoretically no longer expected to dominantly limit the T2T_{2} spin dephasing time. We also demonstrate a complete suppression of hysteretic gate behavior and charge noise using a negatively biased global top gate.Comment: 4 pages, 3 figure

    Web-based instruments for strengthening sustainable regional development in the Alps

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    Web-based information and communication technologies enable the inclusion of all stakeholders in sustainable regional development and raise hopes that these processes will be accomplished from the bottom up and with broad public participation. This article synthesizes, presents, and critically discusses solutions for the Alps that use web 2.0 technologies, in particular: (a) GALPIS and DIAMONT with databases and an interactive webGIS, (b) mountain.TRIP as an efficient communication and information system to link research with practice, and (c) mountain wikis as tools for collaborative regional planning and development. The results indicate that new information and communication instruments enhance the implementation, promotion, assessment, and steering of sustainable regional development in the Alps

    Perfectly localized Majorana corner modes in fermionic lattices

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    Focusing on examples of Majorana zero modes on the corners of a two-dimensional lattice, we introduce a method to find parameter regions where the Majorana modes are perfectly localized on a single site. Such a limit allows us to study the dimerization structure of the sparse bulk Hamiltonian that results in the higher-order topology of the system. Furthermore, such limits typically provide an analytical understanding of the system energy scales. Based on the dimerization structure we extract from the two-dimensional model, we identify a more general stacking procedure to construct Majorana zero modes in arbitrary corners of a dd-dimensional hypercube, which we demonstrate explicitly in d≀3d\leq3.Comment: 12 pages, 12 figure

    Dystopian utopia between mountain and the sea? Second-home production along the Coastal Cordillera of Central Chile 1992-2012

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    In recent decades the expansion of the metropolitan areas in Central Chile has produced numerous forms, structures and functions. The amenities of the environment and local food and culture have been used to promote a utopia for future residents, which include many people who have purchased a second home. However in many cases the migrants have suffered frustrations. They found dystopia instead of the promised utopia. By intensifying the metropolization of Central Chile, the real estate sector has produced a space not unlike the spatial conditions the migrants hoped to escape. Pristine environments were transformed into polluted areas, suffering from rapid urbanization, noise, rubbish and an overload of visitors in formerly untouched areas. In this paper we analyse the socio-economic impact and the perception of second-home development. Many of the new apartments, flats and houses are used as second homes, introducing and enhancing new forms of multilocality. The infrastructure is designed for full occupation, yet during many periods of the year it is not used, and those who live there all year round seem lost in large areas devoid of life
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