30,723 research outputs found
Generalized externality games: economic applications.
This paper analyzes two specific economic problems: The division of profits between associated firms and the distribution of cost of a public good. We tackle these problems using game theoretic techniques. To do so, a new c1ass of games in characteristic function form, called Generalizad Externality Games is defined in this paper. Sorne attractive features of this c1ass of games are that the core is non-empty and that these new games there seems to be a connection with relational goods.Cooperative Games; Balanced Games; Core; Coob-Douglas Production; Public Goods; Relations Goods;
Taxonomic revision of the genus Alternanthera (Amaranthaceae) in Italy
A taxonomic revision of the genus Alternanthera (Amaranthaceae) in Italy is here presented. Field surveys were carried out during the period 2007–2013. Thirty-six herbaria (both European and American) were consulted as well as extensive literature was analyzed. Four taxa are recognized, all of them to be considered aliens native to South America. Information about nomenclature (accepted names, main synonyms, and types), morphology, chromosome number, alien status (at national and regional levels), occurrence in Italy (at regional and provincial scale), ecology (preferential habitat, phenology, and elevation), taxonomical notes, and Italian vernacular names were provided for each taxon. A diagnostic key was given. For the nomenclatural purposes the generic name Alternanthera and its type was discussed, and the names A. paronychioides and A. pungens were studied and typified (lecto- and neotype, respectively) on specimens preserved at PH and P
Neoadjuvant endocrine therapy for luminal breast cancer treatment: a first-choice alternative in times of crisis such as the COVID-19 pandemic
The epidemiological emergency caused by CoV-2 (COVID-19) has changed priorities in breast cancer management. In those places where the pandemic has had the greatest effect, it is of paramount importance for most patients to be at home, reducing or postponing their attendance at clinics, as well as avoiding surgeries. In this scenario, neoadjuvant endocrine treatment could be an appropriate alternative treatment for hormone receptor positive breast cancer (luminal-like tumours) in order to minimise hospital admissions and to delay elective surgeries. Accordingly, we present a simple protocol that can be applied to most cases of luminal-like breast cancer and is appropriate for the majority of secondary or tertiary medical centres, or even primary car
A fast version of the k-means classification algorithm for astronomical applications
Context. K-means is a clustering algorithm that has been used to classify
large datasets in astronomical databases. It is an unsupervised method, able to
cope very different types of problems. Aims. We check whether a variant of the
algorithm called single-pass k-means can be used as a fast alternative to the
traditional k-means. Methods. The execution time of the two algorithms are
compared when classifying subsets drawn from the SDSS-DR7 catalog of galaxy
spectra. Results. Single-pass k-means turn out to be between 20 % and 40 %
faster than k-means and provide statistically equivalent classifications. This
conclusion can be scaled up to other larger databases because the execution
time of both algorithms increases linearly with the number of objects.
Conclusions. Single-pass k-means can be safely used as a fast alternative to
k-means
Separability conditions from the Landau-Pollak uncertainty relation
We obtain a collection of necessary (sufficient) conditions for a bipartite
system of qubits to be separable (entangled), which are based on the
Landau-Pollak formulation of the uncertainty principle. These conditions are
tested, and compared with previously stated criteria, by applying them to
states whose separability limits are already known. Our results are also
extended to multipartite and higher-dimensional systems.Comment: 20 page
Transport properties of armchair graphene nanoribbon junctions between graphene electrodes
The transmission properties of armchair graphene nanoribbon junctions between
graphene electrodes are investigated by means of first-principles quantum
transport calculations. First the dependence of the transmission function on
the size of the nanoribbon has been studied. Two regimes are highlighted: for
small applied bias transport takes place via tunneling and the length of the
ribbon is the key parameter that determines the junction conductance; at higher
applied bias resonant transport through HOMO and LUMO starts to play a more
determinant role, and the transport properties depend on the details of the
geometry (width and length) of the carbon nanoribbon. In the case of the
thinnest ribbon it has been verified that a tilted geometry of the central
phenyl ring is the most stable configuration. As a consequence of this rotation
the conductance decreases due to the misalignment of the orbitals between
the phenyl ring and the remaining part of the junction. All the computed
transmission functions have shown a negligible dependence on different
saturations and reconstructions of the edges of the graphene leads, suggesting
a general validity of the reported results
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