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  • 2010-2014  (108)
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  • 1
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    Pavia: Università degli Studi di Pavia, Dipartimento di Economia Politica e Metodi Quantitativi (EPMQ)
    Publication Date: 2018-06-28
    Description: Let (S, B, G ) and (T, C,Q) be probability spaces, with Q nonatomic, and H = {h in C : Q(H) 〉 0}. In some economic models, the following conditional law of large numbers (LLN) is requested. There are a probability space (O,A,P) and a process X = {Xt : t in T}, with state space (S, B), satisfying for each h in H, there is Ah in A with P(Ah) = 1 such that t --〉 X(t, w) is measurable and Q {t : X(t, w) in ·} h = G(·) for w in Ah. If is not trivial and the sigma-field C countably generated, the conditional LLN fails in the usual (countably additive) setting. Instead, as shown in this note, it holds in a finitely additive setting. Also, X can be taken to have any given distribution. In fact, for any consistent set P of finite dimensional distributions, there are a finitely additive probability space (O,A,P) and a process X such that X tilde P and the conditional LLN is satisfied.
    Keywords: ddc:330 ; Aggregate uncertainty ; Extension ; Finitely additive probability measure ; Individual risk ; Law of large numbers
    Repository Name: EconStor: OA server of the German National Library of Economics - Leibniz Information Centre for Economics
    Language: English
    Type: doc-type:workingPaper
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  • 2
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    In:  [Talk] In: 2. International Symposium on Submarine Canyons, 29.09-01.10.2014, Edinburgh, UK .
    Publication Date: 2017-06-19
    Description: Predictive habitat mapping has shown great promise to improve the understanding of the spatial distribution of benthic habitats. However, although they surely represent an important step forward in process-based ecosystem management, their predictive efficiency is not always tested by independent groundtruthing data. This is particularly true for the deep-sea environment, where sample data are always limited compared to the large extent of the areas to be mapped. The aim of this study is to apply and test different spatial models to statistically predict the distribution of three Cold-Water Coral (CWC) species (Madrepora oculata, Lophelia pertusa and Dendrophyllia cornigera) in the Cap de Creus Canyon (NW Mediterranean), based on high-resolution swath-bathymetry data and video observations from the submersible JAGO (IFM-GEOMAR). Submarine canyons act as specific hosting areas for CWCs, owing to their favourable environmental conditions, which provide habitat and shelter for a wide range of species, including commercially viable fish. Maximum Entropy (MaxEnt), General Additive Model (GAM) and decision tree model (Random Forest) were independently applied to represent non-linear species-environment relationships using terrain variables derived from multibeam bathymetry (slope, geomorphologic category, rugosity, aspect, backscatter). Relevant differences between the three models were observed. Nonetheless, the predicted areas where CWCs should be found with higher probabilities coincided for the three methods when a lower spatial scale was considered. According to the models, CWCs are most likely to be found on the medium to steeply sloping, rough walls of the southern flank of the canyon, aligning with the known CWC ecology acquired from previous studies in the area. As a final step, a probabilistic predictive ensemble has been produced merging the outcomes of the three models considered, providing a more robust prediction for the three species. The main insight is that important discrepancies can arise in using different species distribution models, especially when high spatial resolutions are considered. This could in part be the result of the different statistical assumptions behind each of the models. We suggest that a more reliable prediction could be obtained by merging models into spatial ensembles, able to reduce differences and associated uncertainties, showing hence a strong potential as an objective approach in the planning and management of natural resources.
    Type: Conference or Workshop Item , NonPeerReviewed
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  • 3
    Publication Date: 2017-06-19
    Description: Cold-water coral (CWC) reefs constitute one of the most complex deep-sea habitats harboring a vast diversity of associated species. Like other tropical or temperate framework builders, these systems are facing an uncertain future due to several threats, such as global warming and ocean acidification. In the case of Mediterranean CWC communities, the effect may be exacerbated due to the greater capacity of these waters to absorb atmospheric CO2 compared to the global ocean. Calcification in these organisms is an energy-demanding process, and it is expected that energy requirements will be greater as seawater pH and the availability of carbonate ions decrease. Therefore, studies assessing the effect of a pH decrease in skeletal growth, and metabolic balance are critical to fully understand the potential responses of these organisms under a changing scenario. In this context, the present work aims to investigate the medium- to long-term effect of a low pH scenario on calcification and the biochemical composition of two CWCs from the Mediterranean, Dendrophyllia cornigera and Desmophyllum dianthus. After 314 d of exposure to acidified conditions, a significant decrease of 70 % was observed in Desmophyllum dianthus skeletal growth rate, while Dendrophyllia cornigera showed no differences between treatments. Instead, only subtle differences between treatments were observed in the organic matter amount, lipid content, skeletal microdensity, or porosity in both species, although due to the high variability of the results, these differences were not statistically significant. Our results also confirmed a heterogeneous effect of low pH on the skeletal growth rate of the organisms depending on their initial weight, suggesting that those specimens with high calcification rates may be the most susceptible to the negative effects of acidification.
    Type: Article , PeerReviewed
    Format: text
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  • 4
    Publication Date: 2017-06-19
    Description: Dissolved organic matter, which contains many compounds such as lipids, sugars and amino acids, is an important source of carbon and nitrogen for several symbiotic and asymbiotic tropical coral species. However, there is still no information on its possible uptake by cold-water coral species. In this study, we demonstrated that dissolved organic matter, in the form of dissolved free amino acids (DFAA), is actively absorbed by four cold-water coral species from the Mediterranean Sea. Although the uptake rates observed with 3 µM DFAA concentration were one order of magnitude lower than those observed in tropical species, they corresponded to 12–50% of the daily excreted-nitrogen, and 16–89% of the daily respired-carbon of the cold-water corals. Consequently, DFAA, even at in situ concentrations lower than those tested in this study, can supply a significant amount of carbon and nitrogen to the corals, especially during periods when particulate food is scarce.
    Type: Article , PeerReviewed
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  • 5
    Publication Date: 2017-06-20
    Description: The spatial variability in the mix of species making up Cold-water coral reef communities is not well known. In this study abundances of a selection of megafauna (Lophelia pertusa, Madrepora oculata, Paragorgia arborea, Primnoa resedaeformis, Mycale lingua, Geodia baretti, Acesta excavata and fish) were quantified throughout 9 manned submersible video transects from 3 reef complexes (Røst Reef, Sotbakken Reef and Traena Reef) on the Norwegian margin. Substrate type (coral structure, rubble, exposed hardground or soft sediment) was also recorded. Variations in the densities of these fauna (with respect to both reef complex and substrate type) were investigated, with spatial covariance between species assessed. For the majority of fauna investigated, densities varied by both reef and substrate. Spatial covariance indicated that some species may be utilising similar habitat niches, but that minor environmental differences may favour colonisation by one or other at a particular reef. Fish densities were generally higher in regions with biogenic substrate (coral structure and coral rubble substrates) than in areas of soft or hardground substrate. Further, fish were more abundant at the northerly Sotbakken Reef at time of study than elsewhere. Community structure varied by reef, and therefore management plans aimed at maintaining the biodiversity of reef ecosystems on the Norwegian margin should take this lack of homogeneity into account.
    Type: Article , PeerReviewed , info:eu-repo/semantics/article
    Format: text
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  • 6
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    Bologna: Alma Mater Studiorum - Università di Bologna, Dipartimento di Scienze Economiche (DSE)
    Publication Date: 2018-02-02
    Description: Empirical evidence shows that an increase in trade liberalisation causes an increase in foreign direct investments (FDIs). Here we propose an explanation to this apparent puzzle by exploiting the intensity of competition in a Bertrand duopoly with convex costs where the two firms enter in a new market. We adopt Dastidar's (1995) approach, delivering a continuum of Bertrand-Nash equilibria ranging above marginal cost pricing, to show that softening competition may indeed more than offset the standard effect generated by trade costs, thereby leading to a positive relationship between trade liberalisation and FDIs.
    Keywords: F12 ; F13 ; F23 ; ddc:330
    Repository Name: EconStor: OA server of the German National Library of Economics - Leibniz Information Centre for Economics
    Language: English
    Type: doc-type:workingPaper
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  • 7
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    Bologna: Alma Mater Studiorum - Università di Bologna, Dipartimento di Scienze Economiche (DSE)
    Publication Date: 2018-02-02
    Description: This paper investigates the impact of free trade on welfare in a two-country world modelled as an international Hotelling duopoly with quadratic transport costs and asymmetric countries, where a negative environmental externality is associated with the consumption of the good produced in the smaller country. Countries' relative sizes as well as the intensity of negative environmental externality affect potential welfare gains of trade liberalisation. In line with Lambertini (1997a) we show that, as long as no trade policy is undertaken by the government of the larger country, trade liberalisation is not feasible since the latter always loses from opening to trade. A subsidy policy in favour of the firm producing the clean good is, on the contrary, shown to give both countries the right incentives to liberalize trade. Allowing for redistributive transfers between countries further extends the parametric range for which trade liberalisation is feasible under the subsidy scheme. The alternative situation, in which the green firm is based in the larger country, is also briefly sketched to find that free trade does give rise to a global welfare increment with no need of accompanying trade policies.
    Keywords: F12 ; L13 ; H23 ; ddc:330
    Repository Name: EconStor: OA server of the German National Library of Economics - Leibniz Information Centre for Economics
    Language: English
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  • 8
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    Bologna: Alma Mater Studiorum - Università di Bologna, Dipartimento di Scienze Economiche (DSE)
    Publication Date: 2018-02-02
    Description: This paper focuses on the functional specialisation of a system of cities, with particular attention to the role and the formation process of secondary business centers. At the European level, the latters can be identified in the large number of regional capitals, and properly defined as cities hosting both headquarters of multi-location firms and providers of standard non-tradable business services (SBS). I present a theoretical model in which the changes in urban system's degree of functional specialisation are linked to (i) firms' organisational choices, since firms decide whether splitting into headquarter and production plant or remaining integrated in a single establishment and to (ii) firms' location decision with regards to the proximity with the tradable advanced business services providers. I model two types of communication costs, one between headquarters and advanced tradable business services providers (ABS) and one between headquarters and production plants. The interplay between the two types of communication costs is shown to have effects on the transition process from an "integrated" urban system where each city hosts every different functions to a "functionally specialised" urban system where each city is either a primary business center (hosting ABS), a secondary business centers (SBS) or a pure manufacturing city and all this city-types coexist in equilibrium. In particular, I find that maximum functional specialisation of the urban system turns out to be feasible only if firms face a very high share of the total costs represented by their heaquarter spending.
    Keywords: R30 ; L23 ; R12 ; ddc:330
    Repository Name: EconStor: OA server of the German National Library of Economics - Leibniz Information Centre for Economics
    Language: English
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  • 9
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    Bologna: Alma Mater Studiorum - Università di Bologna, Dipartimento di Scienze Economiche (DSE)
    Publication Date: 2018-02-02
    Description: This paper investigates the relationship between trade liberalisation, consumers' environmental awareness and a negative environmental externality in consumption. We adopt an international Hotelling duopoly setup, where firms are located in two asymmetric countries. We find that, if the intensity of environmental externality is common knowledge for country governments, this setup delivers no need of accompanying trade policies in order to enforce trade liberalisation. In the opposite case, in which information is asymmetric, i.e., the small country's Government cannot observe the positive enviromental effects of its firm's exports to foreign consumers, we find that: (i) the Pareto optimum is always enforced, since the brown country always relaxes the distortionary trade policy, and (ii) cheating on the environmental externality allows the brown country's government to extract extra surplus from the green country. Allowing for trade in green technology delivers opposite conclusions: the externality is minimised and welfare is maximised in equilibrium if information is symmetric while trade liberalisation with asymmetric information always entails a second best outcome.
    Keywords: F12 ; L13 ; H23 ; ddc:330
    Repository Name: EconStor: OA server of the German National Library of Economics - Leibniz Information Centre for Economics
    Language: English
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  • 10
    Publication Date: 2019-03-28
    Description: The EU legislation has undergone a radical change in 2008, handling the Italian legislature the necessity to rethink on fundamental aspects of the national legislation. The changes were focused on the procedure of formation and revision of the designations of origin, opening up new and important perspectives for Consortia since, as inter-branch organizations, they can be acknowledged as representatives of the economic activities linked to the production and at least to one of the phases of processing or trade. The Consortium has become responsible for production specification, stock managing, new registration of the vines to a DO, supervision and protection.
    Keywords: ddc:330 ; Consortia ; EU legislation ; Italian legislation ; Italian production system
    Repository Name: EconStor: OA server of the German National Library of Economics - Leibniz Information Centre for Economics
    Language: English
    Type: doc-type:article
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