934 research outputs found

    Semilattices of groups and inductive limits of Cuntz algebras

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    We characterize, in terms of elementary properties, the abelian monoids which are direct limits of finite direct sums of monoids of the form ðZ=nZÞ t f0g (where 0 is a new zero element), for positive integers n. The key properties are the Riesz refinement property and the requirement that each element x has finite order, that is, ðn þ 1Þx ¼ x for some positive integer n. Such monoids are necessarily semilattices of abelian groups, and part of our approach yields a characterization of the Riesz refinement property among semilattices of abelian groups. Further, we describe the monoids in question as certain submonoids of direct products L G for semilattices L and torsion abelian groups G. When applied to the monoids VðAÞ appearing in the non-stable K-theory of C*-algebras, our results yield characterizations of the monoids VðAÞ for C* inductive limits A of sequences of finite direct products of matrix algebras over Cuntz algebras On. In particular, this completely solves the problem of determining the range of the invariant in the unital case of Rørdam’s classification of inductive limits of the above type

    La intensidad de la externalización hotelera y sus beneficios y riesgos percibidos

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    Este trabajo se centra en identificar el papel de la estrategia de externalización en los hoteles. Para ello, se analiza los niveles de externalización actual y deseada. El artículo intenta determinar qué ventajas así como los riesgos que perciben los directivos de esta estrategia. Por otra parte se analiza la relación entre el tamaño, categoría y tipo de hotel con la externalización. Los resultados indican que el nivel de externalización es bastante usado. Por otra parte, los beneficios que perciben los directivos son más tácticos que estratégicos. Existe una relación entre la externalización y el tamaño del hotel

    Short-Term Response of Chlorophyll a Concentration Due to Intense Wind and Freshwater Peak Episodes in Estuaries: The Case of Fangar Bay (Ebro Delta)

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    Estuaries and coastal bays are areas of large spatio-temporal variability in physical and biological variables due to environmental factors such as local wind, light availability, freshwater inputs or tides. This study focuses on the effect of strong wind events and freshwater peaks on short-term chlorophyll a (Chl a) concentration distribution in the small-scale and microtidal, Fangar Bay (Ebro Delta, northwestern Mediterranean). The hydrodynamics of this bay are primarily driven by local wind episodes modulated by stratification in the water column. Results based on field-campaign observations and Sentinel-2 images revealed that intense wind episodes from both NW (offshore) and NE-E (onshore) caused an increase in the concentration of surface Chl a. The mechanisms responsible were horizontal mixing and the bottom resuspension (also linked to the breakage of the stratification) that presumably resuspended Chl a containing biomass (i.e., micropyhtobentos) and/or incorporated nutrients into the water column. On the other hand, sea-breeze was not capable of breaking up the stratification, so the chlorophyll a concentration did not change significantly during these episodes. It was concluded that the mixing produced by the strong winds favoured an accumulation of Chl a concentration, while the stratification that causes a positive estuarine circulation reduced this accumulation. However, the spatial-temporal variability of the Chl a concentration in small-scale estuaries and coastal bays is quite complex due to the many factors involved and deserve further intensive field campaigns and additional numerical modelling efforts.info:eu-repo/semantics/publishedVersio

    CAMCAT: an oil spill forecasting system for the Catalan-Balearic Sea based on the MFS products

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    International audienceThe Prestige oil spill crisis (2002?2003), one of the worst oil spills that affected the Atlantic Spanish coastal line, pointed out that some management tools are needed in the form of laws, regulations and technical procedures. In particular, the issues are contingency planning and prevention against marine pollution and prediction for a proper response. In that background, the Catalan local government approved the CAMCAT (2004), a Regional contingency plan against marine pollution, to be framed within the (Spanish) National Contingency Plan. The CAMCAT contemplated the implementation of a Regional Forecasting System for the North-Western Mediterranean area, intended to help Catalan Authorities during any pollution emergency. The Laboratory of Maritime Engineering (LIM/UPC) has been responsible for the implementation of this Regional CAMCAT Forecasting System that is based (nested) on existing larger Forecasting Systems/Products, and it integrates several coastal observational data. The present paper is aiming to make an overview of the several scientific and technical activities related to the implementation and validation of the CAMCAT System

    Survey of rice storage facilities identifies research and education needs

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    More than 40 million hundredweights of rice are produced in California's Sacramento Valley every year. After harvest, the rice is stored in facilities on-farm or off-farm until it is transported to mills or to ports for export. We conducted a survey of storage operations to characterize grain storage and pest management practices to guide future UC Cooperative Extension research efforts. The results indicate that grain moisture content, temperature and insect pest management are the most important challenges for both on- and off-farm storage operations. Survey responses show high adoption of integrated pest management programs, with most storage operations relying on monitoring, thresholds, sanitation and aeration to manage pest problems. Fumigant use was reported more frequently in off-farm storage operations than on-farm operations. Cooperative Extension educational efforts should focus on grain and temperature monitoring, insect identification and safe use of fumigants. Research is needed to improve management of grain temperature and moisture content, and insect infestations

    A systematic review on the ecosystem services provided by green infrastructure

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    Urbanization and climate change are endangering the sustainability of public spaces through increased land artificialization, ecological fragmentation, reduced resource availability, and limited accessibility to natural and seminatural areas. Properly managing Green Infrastructure (GI) can contribute to mitigating these challenges by delivering multiple provisioning, regulating, supporting and cultural Ecosystem Services (ES). This would facilitate the implementation of strategically planned GI networks in cities for urban regeneration purposes. In this context, this study developed a systematic review on the ES provided by GI using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. The analysis of 199 eligible articles indicated that more efforts should be made to address more ES at once, which connects to the need for conceiving GI as a strategically planned network of areas aimed at delivering diverse benefits. Based on the methods used in the items reviewed, geoprocessing tools and multi-criteria decision analysis are proposed to develop systems of indicators capable of accounting for multiple ES. These systems should also rely on multidisciplinary and participative procedures to encompass various facets of GI and represent the priorities of all relevant stakeholders

    Do relational norms matter in hotel outsourcing relationships? Lesson learned from hotel sectors

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    The study examines relational norms in outsourcing relationships. The study analyzes some factors that determine the use of relational norms, such as outsourcing benefits and the competitive strategy (cost leadership and differentiation). In addition, it analyzes the influence of the use of relational norms on the outsourcing success. Based on a sample of 127 outsourcing relationships in two tourist destinations, a PLS structural model was used to test the hypotheses. The findings show that the outsourcing benefits and competitive strategy determine the use of relational norms. They also show that there is a positive relationship between relational norms and outsourcing success. Some differences were found between the two destinations analyzed
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