2,046 research outputs found
(2290) Proposal to conserve the name Verrucaria subcerasi (Arthopyrenia subcerasi) against Arthopyrenia subalbicans (lichenized Ascomycota: Arthopyreniaceae)
No full textExamination of historical samples of Arthopyrenia subalbicans
Bagl. & Carestia during a visit to the lichen herbarium at the Royal
Botanic Garden Edinburgh, showed that it falls within the current
concept of the epiphytic Arthopyrenia subcerasi (Vain.) Zahlbr., a name lectotypified by Coppins
Epiphytic lichens as indicators of environmental quality in Rome
No full textA synthesis of the studies on lichen diversity carried out in Rome over the period 1982-2003 is presented. In this work, the Lichen Diversity (LD) method has been applied. Besides air pollution, the most important variable affecting the epiphytic lichen flora of Rome, currently updated to 102 taxa, is the influence of the Tyrrhenian Sea. Significant changes in the lichen flora have been noted over the past 20 years, with the lowest diversity now being found in the urban centre and in the eastern and southern sectors, while the "lichen desert" area has decreased in parallel with decreasing concentrations of CO, NOx and SO2
Sähköautojen latausratkaisut : Latausasemien vertailu ja markkinointi
No full textOpinnäytetyö tehtiin Oy Ravera Ab:lle. Työssä tutkitaan kotitalouksiin tarkoitettuja eri valmistajien tarjoamia sähköautojen latausasemia. Tarkoituksena on, että Ravera aloittaa latureiden palveluntarjoajana. Selvitettiin, olisiko autoliikkeiden keskuudessa tarvetta kokonaiselle pakettiratkaisulle.
Opinnäytetyössä käydään läpi markkinoiden erilaiset sähköautotyypit ja tutkitaan niiden toimintaa sekä vertaillaan, mitä eroavaisuuksia niillä on. Lisäksi esitellään erilaiset lataustavat sähköajoneuvoille ja kerrotaan, minkälaisia vaatimuksia on asetettu eri lataustavoille. Työssä käydään läpi sähköajoneuvon lataamisen erilaisia vaihtoehtoja taloyhtiössä kuormanhallinta huomioiden. Lisäksi selvitetään, kuinka muutostöistä johtuvat kustannukset voitaisiin jakaa erilaisissa tapauksissa tasapuolisesti.
Opinnäytetyön tulokseksi tuli sähköautojen latausratkaisuja selvittävä työ, joka helpottaa tämänhetkisten latausasemien valinnan päätöstä, joita markkinoilla on tarjottavana. Sähköautot ja niiden latausjärjestelmät kehittyvät jatkuvasti, ja uusia tekniikoita sekä malleja tuodaan markkinoille aktiivisesti.The thesis was done for Oy RAVERA Ab. The thesis examines the charging stations for electric cars provided by different manufactures. Ravera´s intention is to start as a provider of chargers. The thesis clarifies whether there would be a need for an entire package solution among car dealers.
Different types of electric cars on the market were looked into, as well as their operating principles from the electric drive point of view and differences between them. Different types of charging methods were also studied and the requirements set for different charging methods. The thesis presents different options of charging an electric vehicle in the house company, considering load management. It was also considered how the costs caused by the alteration work could be shared equally in various cases.
The result of the thesis is a study examining various charging methods for electric cars. The study helps to choose a right type of charging station. Electric cars and their charging systems are evolving continuously. New technologies and models are actively being introduced to the market
An action principle for the Einstein–Weyl equations
No full textA longstanding open problem in mathematical physics has been that of finding an action principle for the Einstein–Weyl (EW) equations. In this paper, we present for the first time such an action principle in three dimensions in which the Weyl vector is not exact. More precisely, our model contains, in addition to the Weyl nonmetricity, a traceless part. If the latter is (consistently) set to zero, the equations of motion boil down to the EW equations. In particular, we consider a metric affine f(R) gravity action plus additional terms involving Lagrange multipliers and gravitational Chern–Simons contributions. In our framework, the metric and the connection are considered as independent objects, and no a priori assumptions on the nonmetricity and the torsion of the connection are made. The dynamics of the Weyl vector turns out to be governed by a special case of the generalized monopole equation, which represents a conformal self-duality condition in three dimensions
On SIR-type epidemiological models and population heterogeneity effects
No full textIn this paper we elaborate on homogeneous and heterogeneous SIR-type epidemiological models. We find an unexpected correspondence between the epidemic trajectory of a transmissible disease in a homogeneous SIR-type model and radial null geodesics in the Schwarzschild spacetime. We also discuss modeling of population heterogeneity effects by considering both a one-and two-parameter gamma-distributed function for the initial susceptibility distribution, and deriving the associated herd immunity threshold. We furthermore describe how mitigation measures can be taken into account by model fitting
L’océan comme pont et frontière entre Afrique et Europe: Le Ventre de l’Atlantique de Fatou Diome
No full textAs foregrounded in the very title of Fatou Diome’s postcolonial autofiction, Le Ventre de l’Atlantique (2003), the Atlantic Ocean is an indispensable and persistent leitmotif that infiltrates both the words and the pages. The text tells the story of Salie, a young Senegalese woman based in Strasbourg, France, while Madické, her little half-brother, still lives in Senegal, on the small island of Niodor. Although she tries to discourage him, the boy would like to join his sister in Europe to pursue his dream of meeting his idol Paolo Maldini and becoming a professional football player. The telephone is their only means of contact in the immense, deep waters that separate them and, at the same time, unite their destinies. While the writer effectively deconstructs the contrast between the myth of a Europe-Eldorado and the dystopia of a poor and hopeless Africa, she also shows the reader how the ocean has many ambiguous and heterogeneous interpretations: on the one hand, the Atlantic can be a prodigious bridge, a liquid umbilical cord connecting the two continents, but, on the other, it is also a hostile and dangerous border, which becomes a tomb for some of the characters in the book. The aquatic presence accompanies the narration not only at the thematic level, but also through several aesthetic and rhetorical solutions, such as the use of metaphor, personification and zoomorphism, as well as of a fluid writing technique which mimics the wave movements of the sea. The article aims to study this stylistic and thematic polymorphism of the Atlantic in Diome’s novel, trying to show its importance for the construction of the author-narrator’s Afro-European identity
Infinite <i>S</i>-expansion with ideal subtraction and some applications
No full textAccording to the literature, the S-expansion procedure involving a finite semigroup is valid no matter what the structure of the original Lie (super)algebra is; however, when something about the structure of the starting (super)algebra is known and when certain particular conditions are met, the S-expansion method (with its features of resonance and reduction) is able not only to lead to several kinds of expanded (super)algebras but also to reproduce the effects of the standard as well as the generalized Inönü-Wigner contraction. In the present paper, we propose a new prescription for S-expansion, involving an infinite abelian semigroup S^(∞) and the subtraction of an infinite ideal subalgebra. We show that the subtraction of the infinite ideal subalgebra corresponds to a reduction. Our approach is a generalization of the finite S-expansion procedure presented in the literature, and it offers an alternative view of the generalized Inönü-Wigner contraction. We then show how to write the invariant tensors of the target (super)algebras in terms of those of the starting ones in the infinite S-expansion context presented in this work. We also give some interesting examples of application on algebras and superalgebras
Epiphytic lichens of a poorly explored National Park: Is the probabilistic sampling effective to assess the occurrence of species of conservation concern?
No full textOver the past 10 years, three National Parks have been established in southern Italy. This bought to the scientific attention the status of natural resources in these territories. The knowledge base completion, that includes also usually neglected organisms, is necessary for managing biodiversity. Although lichens are not included in the European conservation policies, they play well-known ecological roles in various ecosystems. The aim of this work is to propose a rapid but exhaustive approach to assess epiphytic lichen diversity in this area. For this purpose, the probabilistic sampling was tested. A total of 149 taxa of epiphytic lichens were recorded, including 20 new records for the Campania region and four new species for Southern Italy. Furthermore, seven red listed species were found. The majority of the recorded taxa can be considered as old-growth indicator species. The results confirm that the probabilistic approach can be efficiently applied to assess lichen diversity in very poorly explored natural areas over large territories. © 2013 Societá Botanica Italiana
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