1,159 research outputs found

    Protocorks and monopole Floer homology

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    We introduce and study a class of compact 4-manifolds with boundary that we call protocorks. Any exotic pair of simply connected closed 4-manifolds is related by a protocork twist, moreover, any cork is supported by a protocork. We prove a theorem on the relative Seiberg-Witten invariants of a protocork before and after twisting and a splitting theorem on the Floer homology of protocork boundaries. As a corollary we improve a theorem by Morgan and Szab\'{o} regarding the variation of Seiberg-Witten invariants with an upper bound which depends only on the topology of the data. Moreover we show that for any cork, only the reduced Floer homology of its boundary contributes to the variation of the Seiberg-Witten invariants after a cork twist.Comment: Improved exposition of protocork twist operation, added paragraph on Morgan-Szab\'{o} number, minor modification

    Molecular and enological characterization of autochthonous <i>Saccharomyces cerevisiae</i> strains isolated from grape-musts and wines Cannonau

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    Fermentation by autochthonous yeasts may produce wines with enological properties that are unique of a specific area or variety of grape must. In order to identify yeast starter strains for the production of the Sardinian wine Cannonau DOC, 66 Saccharomyces cerevisiae strains, isolated from musts and wines Cannonau of six vitivinicole areas in Sardinia, were subjected to enological characterization and molecular identification. The RFLP-PCR fingerprinting of the ITS region of rRNA (ITS1-5,8S- ITS2) as well as ethanol, foam, and H2S production were analysed

    Total Factor Productivity Growth and Employment: A Simultaneous Equations Model Estimate

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    This paper provides a structural estimation of the recent model proposed by Pissarides and Vallanti, a simplified equilibrium model which draws heavily on models with frictions and quasi-rents. The structural model is a system of three equations. The estimation method is a three-stage least squares. My empirical results find that although faster TFP growth temporarily decreases employment, most likely be- cause job destruction reacts faster to schocks than job creation does, after the first year I do not find any statistically significant effect of growth on employment

    Bridging the Gaps for a ‘Circular’ Bioeconomy: Selection Criteria, Bio-Based Value Chain and Stakeholder Mapping

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    Bio-products and bio-based value chains have been identified as one of the most promising pathways to attaining a resource-efficient circular economy. Such a “valorization and value-addition” approach incorporates an intricate network of processes and actors, contributing to socio-economic growth, environmental benefits and technological advances. In the present age of limited time and funding models to achieve ambitious sustainable development targets, whilst mitigating climate change, a systematic approach employing two-tier multi-criteria decision analysis (MCDA) can be useful in supporting the identification of promising bio-based value chains, that are significant to the EU plans for the bio-economy. Their identification is followed by an elaborate mapping of their value chains to visualize/foresee the strengths, weaknesses, opportunities and challenges attributable to those bio-based value chains. To demonstrate this methodology, a systematic review of 12 bio-based value chains, prevalent in the EU, sourcing their starting material from biomass and bio-waste, has been undertaken. The selected value chains are mapped to visualize the linkages and interactions between the different stages, chain actors, employed conversion routes, product application and existing/potential end-of-life options. This approach will help chain-actors, particularly investors and policy-makers, understand the complexities of such multi-actor systems and make informed decisions

    Marketing and distribution of fish from Lake Chad

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    This study provides information on fish quantities, economic data and flows of Doro fish market near Baga, Nigeria, known as the major fish market on the Nigeria section of the Lake Cha

    ICCSA 2022

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    Producción CientíficaThe process of economic, social, and cultural development leads to relevant changes in urban areas. Urban transformations usually generate a series of public and private real estate compounds which constitute real obstacles to urban walkability. The growing attention towards the sustainable development goals established on a global scale introduced new contents in urban redevelopment policies, aimed at favoring higher levels of accessibility in the consolidated fabric, particularly that of the pedestrian type. In addition, the recent pandemic has recently reassessed the role of pedestrian mobility as a primary way of moving instead of using other means of transport. As a result, urban walkability has moved at the core of the sustainable city paradigm. More precisely, issues related to accessibility and walkability should be considered when addressing the obstacle generated by those sites that can be properly defined ‘urban enclaves’, especially when abandoned or under redevelopment. These conditions may encourage the gradual reopening of these areas for citizens. Within this framework, the Sustainable Urban Mobility Plan (SUMP) can represent a strategic tool for identifying the critical aspects to face for the creation of a new network of pedestrian routes aimed at improving urban walkability. The objective of this study is to define a set of principles and criteria, both tangible and intangible, for calculating the proximity index (PI). The PI may consequently drive urban regeneration projects also through the design of new paths for crossing the enclaves to improve urban permeability and, therefore, the level of walkabilitySardinia Foundation (CUP F74I19001040007

    A methodological approach on disused public properties in the 15-minute city perspective

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    Accessibility and Walkability represent, today, some of the most striking challenges contemporary cities are facing, particularly in light of the goals from UN Agenda 2030, aimed at a sustainable city, and particularly in terms of a livable, healthy and inclusive city. This can be also performed thanks to a set of high quality public services and a set of important and central services and infrastructures. These principles, however, are constrained by an overall, general fragmentation affecting many urban areas, particularly as an outcome of the vehicular accessibility needs. Scholars have debated through the years on the nature of cities and on the preference for centrality of services compared to the distribution of services towards dispersed neighborhood units. Recently, a need for a wider, minimum set of services that is easily reachable to most citizens is filling the scholars and city mayors’ agendas in order to improve urban performances. This is also coupled with a huge surge in the heritage of abandoned urban items coming from previous periods of time and alternative uses. The aim of this research is to evaluate the role of abandoned urban assets—particularly big-size buildings and compounds and their areas—to facilitate the implementation of the concept of a 15-minute city, a city that is capable of granting a wider social equality and access to main urban services to citizens and city users. To do this, we developed a set of indexes, capable of detecting porosity, crossing and attractiveness. This latter index in particular represents a combined index that can be used to improve the accessibility of pedestrians in urban central locations. In the present research, we decided to limit the analysis to a subset of disused public buildings in the historic center of a sample city, as Cagliari (Sardinia, Italy). This was done in order to understand if and in which terms they can contribute, after their redevelopment, to the development of the 15-minute city, as well as reducing the “enclave–effect: they are, at present, playing in the historic urban fabric
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