77 research outputs found

    Construção da qualidade em sistemas agroalimentares localizados (Sial)1,2.

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    O enfoque dos sistemas agroalimentares localizados (Sial) tem oferecido novas perspectivas para a análise dos arranjos produtivos, complementando e ampliando os referenciais sobre clusters e distritos industriais. Por meio desse enfoque, a análise de fatores físicos, institucionais, culturais e relacionais do território possibilita uma visão mais dinâmica dos processos subjacentes à criação, persistência e evolução desses arranjos. Entretanto, os estudos sob esse enfoque têm enfatizado apenas alguns desses fatores. O objetivo desta pesquisa foi dialogar com esse enfoque a partir da análise de como esses fatores se articulam e se integram na consolidação de arranjos produtivos voltados para a qualificação de produtos locais. Para isso, analisou-se o caso de um arranjo vitivinícola situado em Montpeyroux, no sul da França. Verificou-se que houve sinergia, complementaridade e um processo de retroalimentação desses fatores na gênese e conformação do arranjo, concluindo-se que metodologias que os considerem de forma integrada podem contribuir para a melhor compreensão dos arranjos em geral e reforçar os pressupostos dos Sial, em particular

    Confining the state of light to a quantum manifold by engineered two-photon loss

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    Physical systems usually exhibit quantum behavior, such as superpositions and entanglement, only when they are sufficiently decoupled from a lossy environment. Paradoxically, a specially engineered interaction with the environment can become a resource for the generation and protection of quantum states. This notion can be generalized to the confinement of a system into a manifold of quantum states, consisting of all coherent superpositions of multiple stable steady states. We have experimentally confined the state of a harmonic oscillator to the quantum manifold spanned by two coherent states of opposite phases. In particular, we have observed a Schrodinger cat state spontaneously squeeze out of vacuum, before decaying into a classical mixture. This was accomplished by designing a superconducting microwave resonator whose coupling to a cold bath is dominated by photon pair exchange. This experiment opens new avenues in the fields of nonlinear quantum optics and quantum information, where systems with multi-dimensional steady state manifolds can be used as error corrected logical qubits

    Species trait shifts in vegetation and soil seed bank during fen degradation

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    Fens in Central Europe are characterised by waterlogged organic substrate and low productivity. Human-induced changes due to drainage and mowing lead to changes in plant species composition from natural fen communities to fen meadows and later to over-drained, degraded meadows. Moderate drainage leads to increased vegetation productivity, and severe drainage results in frequent soil disturbances and less plant growth. In the present article, we analyse changes in plant trait combinations in the vegetation and the soil seed bank as well as changes in the seed bank types along gradient of drainage intensity. We hypothesize that an increase in productivity enhances traits related to persistence and that frequent disturbance selects for regeneration traits. We use multivariate statistics to analyse data from three disturbance levels: undisturbed fen, slightly drained fen meadow and severely drained degraded meadow. We found that the abundance of plants regenerating from seeds and accumulating persistent seed banks was increasing with degradation level, while plants reproducing vegetatively were gradually eliminated along the same trajectory. Plants with strong resprouting abilities increased during degradation. We also found that shifts in trait combinations were similar in the aboveground vegetation and in soil seed banks. We found that the density of short-term persistent seeds in the soil is highest in fen meadows and the density of long-term persistent seeds is highest in degraded meadows. The increase in abundance of species with strong regeneration traits at the cost of species with persistence-related traits has negative consequences for the restoration prospects of severely degraded sites

    Comparaison des trajectoires d'innovation pour la sécurisation alimentaire des pays du Sud

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    Comparison of innovation paths for food security in countries of the South. Description of the subject. The evolution of the concept of food security and of food securization emphasizes the multi-dimensionality of food challenges (quantity, quality, affordability, identity, stability, etc.). This implies strengthening the innovation capacity of populations faced with food insecurity. Objectives. The objective of this study was to analyze how the concept of innovation system structures different trajectories of innovation for food security in developing countries. Method. A literature review firstly examines the application of this concept within the agricultural and food sector (SIA). The application of the concept is then tested in two case studies. Results. A first type of "productivist" path hypothesizes that food security necessitates increased availability and thus requires industrial input. This type of path re-emerged during the 2008 financial crisis in a form that included biotechnological potentialities, and retained a linear conception of innovation. This type of path is limited by environmental and social externalities as well as in terms of efficiency in relation to food security, in particular in the less developed countries undergoing demographic transition. The second type of path is based on a multi-dimensional approach and on the notion of food securization. Innovation will foster an ecological transition of the production function in the food sector. This approach is based on the promotion of local resources and involves a change in the innovation model. This change is illustrated in two case studies, one on plantain in Cameroon, the other on yam in Haiti. Conclusions. The results confirm the success of a process of the co-construction of innovation. The strengthening of local innovation capacities provides opportunities to realize the potentialities of agrosystems for food security

    Coherent Oscillations inside a Quantum Manifold Stabilized by Dissipation

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    Manipulating the state of a logical quantum bit (qubit) usually comes at the expense of exposing it to decoherence. Fault-tolerant quantum computing tackles this problem by manipulating quantum information within a stable manifold of a larger Hilbert space, whose symmetries restrict the number of independent errors. The remaining errors do not affect the quantum computation and are correctable after the fact. Here we implement the autonomous stabilization of an encoding manifold spanned by Schrödinger cat states in a superconducting cavity. We show Zeno-driven coherent oscillations between these states analogous to the Rabi rotation of a qubit protected against phase flips. Such gates are compatible with quantum error correction and hence are crucial for fault-tolerant logical qubits
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