2,843 research outputs found

    Beyond Copenhagen: A climate policymaker's handbook

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    It is still unclear what a post-Kyoto international regime to tackle climate change will look like. Negotiations on a post-2012 framework are revisiting questions that arose when the Kyoto Protocol was put in place Â? such as how targets can best be shared out, and how the different interests of rich and poor countries can be addressed Â? but policymakers must also face new realities. Scientific evidence shows that the climate policies formulated so far are unfit to deal with the magnitude of the challenge. This book looks realistically at the options for a deal to succeed the Kyoto Protocol. It sets out some of the main ingredients that will have to be included for finalisation of an economically rational agreement that stands a real chance of addressing the threat to the climate system. It critically analyses the European Union's climate policies before reviewing the key elements of such an agreement: carbon markets, flexible mechanisms for transferring money and technology to developing countries, innovation, and the effective enforcement of a global climate deal. The contributors to the volume are Joseph E Aldy, Valentina Bosetti, Carlo Carraro, Juan Delgado, Denny Ellerman, Dieter Helm, Axel Michaelowa, Robert N Stavins and Massimo Tavoni. The French Ministère de lâ??Ecologie, de lâ??Energie, du Développement durable et de la Mer, under the auspices of the 2008 French Presidency of the Council of the European Union, contributed financial support to the production of this volume.

    Practical computational advantage from the quantum switch on a generalized family of promise problems

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    The quantum switch is a quantum computational primitive that provides computational advantage by applying operations in a superposition of orders. In particular, it can reduce the number of gate queries required for solving promise problems where the goal is to discriminate between a set of properties of a given set of unitary gates. In this work, we use Complex Hadamard matrices to introduce more general promise problems, which reduce to the known Fourier and Hadamard promise problems as limiting cases. Our generalization loosens the restrictions on the size of the matrices, number of gates and dimension of the quantum systems, providing more parameters to explore. In addition, it leads to the conclusion that a continuous variable system is necessary to implement the most general promise problem. In the finite dimensional case, the family of matrices is restricted to the so-called Butson-Hadamard type, and the complexity of the matrix enters as a constraint. We introduce the ``query per gate'' parameter and use it to prove that the quantum switch provides computational advantage for both the continuous and discrete cases. Our results should inspire implementations of promise problems using the quantum switch where parameters and therefore experimental setups can be chosen much more freely.Comment: 14 pages, 5 figures; more detailed Sections 4 and 5, added new references for section 5, other minor change

    Minimal nets and minimal minimal surfaces

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    The 3-periodic nets of genus 3 ('minimal nets') are reviewed and their symmetries re-examined. Although they are all crystallographic, seven of the 15 only have maximum-symmetry embeddings if some links are allowed to have zero length. The connection bet

    Using geographical analysis to identify child health inequality in sub-Saharan Africa

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    One challenge to achieving Millennium Development Goals was inequitable access to quality health services. In order to achieve the Sustainable Development Goals, interventions need to reach underserved populations. Analyzing health indicators in small geographic units aids the identification of hotspots where coverage lags behind neighboring areas. The purpose of these analyses is to identify areas of low coverage or high need in order to inform effective resource allocation to reduce child health inequity between and within countries. Using data from The Demographic and Health Survey Program surveys conducted in 27 selected African countries between 2010 and 2014, we computed estimates for six child health indicators for subnational regions. We calculated Global Moran’s I statistics and used Local Indicator of Spatial Association analysis to produce a spatial layer showing spatial associations. We created maps to visualize sub-national autocorrelation and spatial clusters. The Global Moran’s I statistic was positive for each indicator (range: 0.41 to 0.68), and statistically significant (p <0.05), suggesting spatial autocorrelation across national borders, and highlighting the need to examine health indicators both across countries and within them. Patterns of substantial differences among contiguous subareas were apparent; the average intra-country difference for each indicator exceeded 20 percentage points. Clusters of cross-border associations were also apparent, facilitating the identification of hotspots and informing the allocation of resources to reduce child health inequity between and within countries. This study exposes differences in health indicators in contiguous geographic areas, indicating that specific regional and subnational, in addition to national, strategies to improve health and reduce health inequalities are warranted

    Nets with collisions (unstable nets) and crystal chemistry

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    Nets in which different vertices have identical barycentric coordinates (i.e. have collisions) are called unstable. Some such nets have automorphisms that do not correspond to crystallographic symmetries and are called non-crystallographic. Examples are

    Climatic vulnerabilities and ecological preferences of soil invertebrates across biomes.

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    Unlike plants and vertebrates, the ecological preferences, and potential vulnerabilities of soil invertebrates to environmental change, remain poorly understood in terrestrial ecosystems globally. We conducted a cross-biome survey including 83 locations across six continents to advance our understanding of the ecological preferences and vulnerabilities of the diversity of dominant and functionally important soil invertebrate taxa, including nematodes, arachnids and rotifers. The diversity of invertebrates was analyzed through amplicon sequencing. Vegetation and climate drove the diversity and dominant taxa of soil invertebrates. Our results suggest that declines in forest cover and plant diversity, and reductions in plant production associated with increases in aridity, can result in reductions of the diversity of soil invertebrates in a drier and more managed world. We further developed global atlases of the diversity of these important soil invertebrates, which were cross-validated using an independent database. Our study advances the current knowledge of the ecological preferences and vulnerabilities of the diversity and presence of functionally important soil invertebrates in soils from across the globe. This information is fundamental for improving and prioritizing conservation efforts of soil genetic resources and management policies

    Qudit surface codes and gauge theory with finite cyclic groups

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    Surface codes describe quantum memory stored as a global property of interacting spins on a surface. The state space is fixed by a complete set of quasi-local stabilizer operators and the code dimension depends on the first homology group of the surface complex. These code states can be actively stabilized by measurements or, alternatively, can be prepared by cooling to the ground subspace of a quasi-local spin Hamiltonian. In the case of spin-1/2 (qubit) lattices, such ground states have been proposed as topologically protected memory for qubits. We extend these constructions to lattices or more generally cell complexes with qudits, either of prime level or of level dℓd^\ell for dd prime and ℓ≥0\ell \geq 0, and therefore under tensor decomposition, to arbitrary finite levels. The Hamiltonian describes an exact Zd≅Z/dZ\mathbb{Z}_d\cong\mathbb{Z}/d\mathbb{Z} gauge theory whose excitations correspond to abelian anyons. We provide protocols for qudit storage and retrieval and propose an interferometric verification of topological order by measuring quasi-particle statistics.Comment: 26 pages, 5 figure

    LĂ©xico Fataluco-PortuguĂŞs

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    Apresentamos nas páginas seguintes uma edição crítica do Léxico Fataluku-Português do padre salesiano Alfonso María Nácher Lluesa, a partir de uma perspectiva antropológica, histórica e linguística. O livro coloca a reimpressão do trabalho que —sob a dactilografia do manuscrito do padre Nácher— foi efectuado pelo linguista Prof. Geoffrey Hull e que foi publicado na revista Estudos de Línguas e Culturas de Timor-Leste, —hoje desaparecida e de difícil aceso— dividido em duas partes, nos anos de 2003 e 2004. Nesse sentido, o objectivo principal da obra é colocar à disposição dum público amplo e dum público académico a obra do padre Nácher, para que sirva de referência para futuras investigações. Assim, o presente livro também é uma homenagem à pessoa do padre Nácher e aos frutos do seu trabalho como missionário em Timor-Leste. O manuscrito original do padre Nácher recolhe definições em português de léxico e expressões em língua Fataluku, assim como a tradução correspondente nas línguas Tétum e Makasae. O léxico recolhido contém uma quantidade significativa de conceitos e expressões referentes ao património cultural, tanto tangível como intangível (rituais, gastronomia, tarefas agrícolas, tradição oral) dos falantes da língua Fataluku. A presente edição do livro está dividida em duas partes, constituindo a segunda parte a reimpressão do trabalho que o Prof. Hull efectuou sobre o texto do padre Nácher. Além disto, o dicionário é precedido duma primeira parte composta por três artigos inéditos que, a partir da Antropologia Social e Cultural, proporcionam um conhecimento académico que permite a contextualização e a valorização do trabalho realizado na devida altura pelo padre Nácher. Esta primeira parte é composta por um artigo de Frederico Delgado Rosa em que analisa a génese das etnografias feitas por missionários e religiosos em Timor-Leste, em que se inclui a do léxico do padre Nácher. Em segundo lugar, apresenta-se uma história de vida do padre Nácher realizada pelo antropólogo e jornalista Efrén Legaspi Bouza e, finalmente, um texto sobre as relações entre o catolicismo e a religião tradicional a partir de uma perspectiva histórico-antropológica, escrito por Alberto Fidalgo Castro. Manuscrito de Alfonso Nácher, 1984 Digitação de Justino Valentim, 1992 Edição de Geoffrey S. Hull, 2003 e 2004 Presente edição, 2012, coordinada por Alberto Fidalgo Castro e Efrén Legaspi Bouz

    Model Development and Validation of Personal Exposure to Volatile Organic Compound Concentrations

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    Background: Direct measurement of exposure to volatile organic compounds (VOCs) via personal monitoring is the most accurate exposure assessment method available. However, its wide-scale application to evaluating exposures at the population level is prohibitive in terms of both cost and time. Consequently, indirect measurements via a combination of microenvironment concentrations and personal activity diaries represent a potentially useful alternative. Objective: The aim of this study was to optimize a model of personal exposures (PEs) based on microenvironment concentrations and time/activity diaries and to compare modeled with measured exposures in an independent data set. Materials: VOC PEs and a range of microenvironment concentrations were collected with active samplers and sorbent tubes. Data were supplemented with information collected through questionnaires. Seven models were tested to predict PE to VOCs in 75% (n = 370) of the measured PE data set, whereas the other 25% (n = 120) was used for validation purposes. Results: The best model able to predict PE with independence of measurements was based upon stratified microenvironment concentrations, lifestyle factors, and individual-level activities. The proposed model accounts for 40–85% of the variance for individual VOCs and was validated for almost all VOCs, showing normalized mean bias and mean fractional bias below 25% and predicting 60% of the values within a factor of 2. Conclusions: The models proposed identify the most important non-weather-related variables for VOC exposures; highlight the effect of personal activities, use of solvents, and exposure to environmental tobacco smoke on PE levels; and may assist in the development of specific models for other locations.peer-reviewe
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