131 research outputs found

    Virus decomposition provides an important contribution to benthic deep-sea ecosystem functioning

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    Virus decomposition provides an important contribution to benthic deep-sea ecosystem functionin

    improvement of bioremediation performance for the degradation of petroleum hydrocarbons in contaminated sediments

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    Microcosm bioremediation strategies were applied to sediments contaminated with hydrocarbons. Experiments were performed in aerobic conditions in a single-step treatment and in a two-step anaerobic-aerobic treatment. In aerobic conditions, either inorganic nutrients or composts were added to the microcosms, while, in the first anaerobic phase of the two-step experiment, acetate and/or allochthonous sulfate-reducing bacteria were used. After the treatment under anaerobic conditions, samples were exposed to aerobic conditions in the presence of compost. In the aerobic treatments, 81% hydrocarbon biodegradation was observed after 43 days in the presence of inorganic nutrients. In aerobic conditions in the presence of mature compost, hydrocarbon biodegradation was 51% after 43 days of treatment, whereas it was 47% after 21 days with fresh compost. The two-step experiment allowed us to obtain a hydrocarbon degradation of 91%, after a first anaerobic step with an inoculum of sulfate-reducing prokaryotes

    Certainty equivalent citation: a generalized class of citation indexes

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    Citation indexes have attracted the interest of many researchers in the recent years. In this paper we propose a new class of citation indexes which is shown to generalize most of the citation indexes in the existing literature (h-, g-, f-, t-index). The class of indexes is obtained borrowing from the notion of ``certainty equivalent income'' or ``equally distributed equivalent income'' which has been largely implemented in the field of risk and inequality measurement. As a result citation orderings are shown to depend on a parameter of concentration/dispersion aversion capturing the value judgments of the decision-maker with respect to the distribution of citations. In order to verify the sensitivity of scientific productivity orderings with respect to concentration/dispersion aversion, an empirical application to a representative sample of Italian academic economists is presented

    Certainty equivalent citation: generalized classes of citation indexes

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    Citation indexes have attracted the interest of many researchers in the recent years. In this paper we propose a new class of citation indexes which is shown to generalize most of the citation indexes in the existing literature (h-, g-, f-, t-index). The class of indexes is obtained borrowing from the notion of ``certainty equivalent income'' or ``equally distributed equivalent income'' which has been largely implemented in the field of risk and inequality measurement. As a result citation orderings are shown to depend on a parameter of concentration/dispersion aversion capturing the value judgments of the decision-maker with respect to the distribution of citations. In order to verify the sensitivity of scientific productivity orderings with respect to concentration/dispersion aversion, an empirical application to a representative sample of Italian academic economists is presented

    Fiscal Illusion and Progressive Taxation with Retrospective Voting

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    We consider the tax progressivity decision of a rent‐maximizing government when voters’ perceptions of the tax price of public goods are biased by cognitive anomalies (i.e., fiscal illusion), and the electorate opts for re‐appointing or for dismissing the incumbent according to a retrospective voting logic. Given electoral and constitutional constraints, we show that the design of the tax system can be sensibly affected by fiscal illusion within the population of voters. Specifically, we find that (i) the tax system is more (less) progressive when taxes and public expenditures are perceived less (more), and (ii) an increase in the median voter’s income may positively or negatively affect tax progressivity depending on the nature (pessimistic or optimistic) of fiscal illusion. The impact of fiscal illusion on tax progressivity is validated by econometric analysis

    Certainty equivalent citation: a generalized class of citation indexes

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    Citation indexes have attracted the interest of many researchers in the recent years. In this paper we propose a new class of citation indexes which is shown to generalize most of the citation indexes in the existing literature (h-, g-, f-, t-index). The class of indexes is obtained borrowing from the notion of ``certainty equivalent income'' or ``equally distributed equivalent income'' which has been largely implemented in the field of risk and inequality measurement. As a result citation orderings are shown to depend on a parameter of concentration/dispersion aversion capturing the value judgments of the decision-maker with respect to the distribution of citations. In order to verify the sensitivity of scientific productivity orderings with respect to concentration/dispersion aversion, an empirical application to a representative sample of Italian academic economists is presented

    Certainty equivalent citation: generalized classes of citation indexes

    Get PDF
    Citation indexes have attracted the interest of many researchers in the recent years. In this paper we propose a new class of citation indexes which is shown to generalize most of the citation indexes in the existing literature (h-, g-, f-, t-index). The class of indexes is obtained borrowing from the notion of ``certainty equivalent income'' or ``equally distributed equivalent income'' which has been largely implemented in the field of risk and inequality measurement. As a result citation orderings are shown to depend on a parameter of concentration/dispersion aversion capturing the value judgments of the decision-maker with respect to the distribution of citations. In order to verify the sensitivity of scientific productivity orderings with respect to concentration/dispersion aversion, an empirical application to a representative sample of Italian academic economists is presented

    Degradation of Hydrocarbons and Heavy Metal Reduction by Marine Bacteria in Highly Contaminated Sediments

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    Investigations on the ability of bacteria to enhance removal of hydrocarbons and reduce heavy metal toxicity in sediments are necessary to design more effective bioremediation strategies. In this study, five bacterial strains, Halomonas sp. SZN1, Alcanivorax sp. SZN2, Pseudoalteromonas sp. SZN3, Epibacterium sp. SZN4, and Virgibacillus sp. SZN7, were isolated from polluted sediments from an abandoned industrial site in the Gulf of Naples, Mediterranean Sea, and tested for their bioremediation efficiency on sediment samples collected from the same site. These bacteria were added as consortia or as individual cultures into polluted sediments to assess biodegradation efficiency of polycyclic aromatic hydrocarbons and heavy metal immobilisation capacity. Our results indicate that these bacteria were able to remove polycyclic aromatic hydrocarbons, with a removal rate up to ca. 80% for dibenzo-anthracene. In addition, these bacteria reduced arsenic, lead, and cadmium mobility by promoting their partitioning into less mobile and bioavailable fractions. Microbial consortia generally showed higher performance toward pollutants as compared with pure isolates, suggesting potential synergistic interactions able to enhance bioremediation capacity. Overall, our findings suggest that highly polluted sediments select for bacteria efficient at reducing the toxicity of hazardous compounds, paving the way for scaled-up bioremediation trials
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