1,878 research outputs found

    Synergies and non-discriminatory access pricing

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    According to the new European telecom regulation, incumbent operators are required to provide access to such bottlenecks on fair, reasonable and non-discriminatory terms. We explore different interpretations of this general rule in a model in which the bottleneck can be used by external (to the bottleneck firm) as well as internal service providers, and also derive some properties of the solution to the bottleneck owner’s maximization problem as well as that of a welfare-maximizing regulator. In particular, we derive an ECPR rule that also corrects for synergies. Next, by imposing certain symmetry requirements we establish a benchmark in which the external service provider is a competitive fringe and internal and external end-users face identical prices and buy identical quantities of the two services. This, we argue, can be dubbed a non-discrimination benchmark. We then show that introducing certain synergies makes the bottleneck want to favour external supply, while making the fringe less competitive has the opposite implication.access regulation; discrimination; ECPR; synergies

    Arithmetic complexity via effective names for random sequences

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    We investigate enumerability properties for classes of sets which permit recursive, lexicographically increasing approximations, or left-r.e. sets. In addition to pinpointing the complexity of left-r.e. Martin-L\"{o}f, computably, Schnorr, and Kurtz random sets, weakly 1-generics and their complementary classes, we find that there exist characterizations of the third and fourth levels of the arithmetic hierarchy purely in terms of these notions. More generally, there exists an equivalence between arithmetic complexity and existence of numberings for classes of left-r.e. sets with shift-persistent elements. While some classes (such as Martin-L\"{o}f randoms and Kurtz non-randoms) have left-r.e. numberings, there is no canonical, or acceptable, left-r.e. numbering for any class of left-r.e. randoms. Finally, we note some fundamental differences between left-r.e. numberings for sets and reals

    Linking Social Values of Wild Reindeer to Planning and Management Options in Southern Norway

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    Norway is home to the last remaining populations of wild mountain reindeer (Rangifer tarandus tarandus) in Europe. Concerns over anthropogenic and natural drivers have led to change in the management regime from a population-based model to an area-based model. More complex management goals, increasing involvement of stakeholders, and larger management units call for improved knowledge about reindeer-related values. We examined the responses of 1000 respondents to 39 statements of attitudes and values associated with wild reindeer presence and the management situation in two reindeer regions of southern Norway. We used a partial least-squares path modeling approach to examine the nexus between the attraction of wild reindeer, sustainability concerns, utilitarian and non-utilitarian values, conflicts, and attitudes toward hunting. The results show that local concepts of the sustainability of reindeer are based on opinions about the ecological requirements as well as the roles reindeer can play in the social and economic development of the communities. The attraction of reindeer is a function of consumptive as well as non-consumptive objectives. Segments of the community with different consumptive orientations can share ideas about the attraction of reindeer, but diverge in their interpretation of the sustainability of the species. Improved knowledge about the diversity and complexity of value orientations associated with wild reindeer can be a useful tool for developing multi-objective management frameworks with a diversity of stakeholders who may share similar values and interests, although they have different experience and knowledge bases.Les toutes dernières populations de rennes sauvages des montagnes (Rangifer tarandus tarandus) de l’Europe se trouvent en Norvège. Des préoccupations sur le plan des motifs anthropiques et des motifs naturels ont donné lieu à la modification du régime de gestion, qui est passé d’un modèle axé sur la population à un modèle axé sur la région. En raison des objectifs de gestion plus complexes, de l’influence accrue des parties prenantes et de secteurs de gestion plus grands, il y a lieu de se doter de meilleures connaissances au sujet des valeurs liées aux rennes. Nous avons examiné les réponses de 1 000 répondants à 39 énoncés relatifs aux attitudes et aux valeurs liées à la présence des rennes sauvages et à la situation de la gestion dans deux régions où évoluent les rennes, dans le sud de la Norvège. Nous avons fait la modélisation du parcours au moyen de la régression partielle par les moindres carrés dans le but d’examiner la connexion entre l’attraction du renne sauvage, les inquiétudes en matière de durabilité, les valeurs utilitaires et non utilitaires, les conflits et les attitudes vis-à-vis de la chasse. Selon les résultats, les concepts locaux de la durabilité du renne reposent sur des opinions au sujet des exigences écologiques ainsi que sur les rôles que peuvent jouer les rennes dans le développement social et économique des collectivités. L’attraction du renne dépend des objectifs de consommation et des objectifs de non-consommation. Les segments de la collectivité ayant des orientations de consommation différentes peuvent partager des idées au sujet de l’attraction du renne, mais leur interprétation de la durabilité de l’espèce diverge. Il serait utile de posséder de meilleures connaissances au sujet de la diversité et de la complexité des orientations de la valeur liées au renne sauvage, car cela pourrait permettre d’élaborer des cadres de gestion à maints objectifs avec une diversité de parties prenantes susceptibles d’avoir des valeurs et des intérêts semblables, bien que leurs connaissances et leurs expériences diffèrent

    Scattering of Fermions off Dilaton Black Holes

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    We discuss how various properties of dilaton black holes depend on the dilaton coupling constant aa. In particular we investigate the aa-dependence of certain mass parameters both outside and in the extremal limit and discuss their relation to thermodynamical quantities. To further illuminate the role of the coupling constant aa we look at a massless point particle in a dilaton black hole geometry as well as the scattering of (neutral) fermions. In this latter case we find that the scattering potential vanishes for the zero angular momentum mode which seems to indicate a catastrophic deradiation when a>1a>1.Comment: 12, Oslo-TP-4-94, USITP-94-

    Open-cycle indirectly fired gas turbine for wet biomass fuels

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    Dexi-Dairy indicator handbook - Sustainability tree and selected indicators for assessing European specialised dairy farms

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    The MilKey project aims at assessing the environmental, economic, and social sustainability of European dairy production systems, and at identifying ‘win-win’ farming practices for sustainable and greenhouse gas (GHG) optimised milk production. In this context, a holistic model was developed to evaluate the sustainability of specialised dairy farms and was entitled DEXi-Dairy. This model has the potential of aiding the identification of GHG and nitrogen (N) emission mitigation options and assessing their effects across multiple sustainability aspects. DEXi-Dairy covers the three sustainability pillars, i.e., environmental, economic, and social. Based on the ‘DEX’ multi-criteria methodology, the model is detailed under the form of a tree structure represented by four main hierarchical layers, i.e., branches, principles, criteria, and indicators. DEXi-Dairy was built following a participatory and interdisciplinary approach by MilKey project partners. It was then tested on three case study farms from Ireland, France, and Germany, respectively, using data from 2020. The DEXi-Dairy indicator handbook describes the sustainability tree and selected indicators to assess dairy production systems over a production year. Overall, this document can be used as a basis to replicate and expand the sustainability assessment framework developed as part of the MilKey project.acceptedVersio

    Genotype Network Intersections Promote Evolutionary Innovation

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    Evolutionary innovations are qualitatively novel traits that emerge through evolution and increase biodiversity. The genetic mechanisms of innovation remain poorly understood. A systems view of innovation requires the analysis of genotype networks—the vast networks of genetic variants that produce the same phenotype. Innovations can occur at the intersection of two different genotype networks. However, the experimental characterization of genotype networks has been hindered by the vast number of genetic variants that need to be functionally analyzed. Here, we use high-throughput sequencing to study the fitness landscape at the intersection of the genotype networks of two catalytic RNA molecules (ribozymes). We determined the ability of numerous neighboring RNA sequences to catalyze two different chemical reactions, and we use these data as a proxy for a genotype to fitness map where two functions come in close proximity. We find extensive functional overlap, and numerous genotypes can catalyze both functions. We demonstrate through evolutionary simulations that these numerous points of intersection facilitate the discovery of a new function. However, the rate of adaptation of the new function depends upon the local ruggedness around the starting location in the genotype network. As a consequence, one direction of adaptation is more rapid than the other. We find that periods of neutral evolution increase rates of adaptation to the new function by allowing populations to spread out in their genotype network. Our study reveals the properties of a fitness landscape where genotype networks intersect and the consequences for evolutionary innovations. Our results suggest that historic innovations in natural systems may have been facilitated by overlapping genotype networks

    Ghrelin receptor (version 2019.4) in the IUPHAR/BPS Guide to Pharmacology Database

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    The ghrelin receptor (nomenclature as agreed by the NC-IUPHAR Subcommittee for the Ghrelin receptor [18]) is activated by a 28 amino-acid peptide originally isolated from rat stomach, where it is cleaved from a 117 amino-acid precursor (GHRL, Q9UBU3). The human gene encoding the precursor peptide has 83% sequence homology to rat prepro-ghrelin, although the mature peptides from rat and human differ by only two amino acids [70]. Alternative splicing results in the formation of a second peptide, [des-Gln14]ghrelin with equipotent biological activity [48]. A unique post-translational modification (octanoylation of Ser3, catalysed by ghrelin Ο-acyltransferase (MBOAT4, Q96T53) [127] occurs in both peptides, essential for full activity in binding to ghrelin receptors in the hypothalamus and pituitary, and for the release of growth hormone from the pituitary [56]. Structure activity studies showed the first five N-terminal amino acids to be the minimum required for binding [4], and receptor mutagenesis has indicated overlap of the ghrelin binding site with those for small molecule agonists and allosteric modulators of ghrelin function [43]. In cell systems, the ghrelin receptor is constitutively active [44], but this is abolished by a naturally occurring mutation (A204E) that results in decreased cell surface receptor expression and is associated with familial short stature [88]

    Anisotropic domain walls

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    We find an anisotropic, non-supersymmetric generalization of the extreme supersymmetric domain walls of simple non-dilatonic supergravity theory. As opposed to the isotropic non- and ultra-extreme domain walls, the anisotropic non-extreme wall has the \emph{same} spatial topology as the extreme wall. The solution has naked singularities which vanish in the extreme limit. Since the Hawking temperature on the two sides is different, the generic solution is unstable to Hawking decay.Comment: 11 pages, LaTeX, 3 PostScript figures, uses amstex and epsfi
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