600,287 research outputs found

    The beetles of St. Lucia, Lesser Antilles (Insecta: Coleoptera): diversity and distributions

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    The published beetle fauna of the island of St. Lucia is summarized. It contains 135 genera, and 175 species in 25 families. Four species are accidentally introduced by human activities. Twenty three species are endemic (restricted) to the island. Twenty seven species on St. Lucia are shared only with other islands of the Lesser Antilles, and 22 species are widespread Antilles endemics. The remaining 56.6% of the fauna is otherwise mostly one which is widely distributed in the Antilles and the Neotropics. This suggests that it is mostly an immigrant fauna originating in the continental Neotropics. Undoubtedly, the actual numbers of species on St. Lucia are many times higher than now reported and may originally have been as high as around 1400 species. Of the St. Lucia species known to occur on other islands, the largest numbers are shared with Guadeloupe (102), St. Vincent (79), and Martinique (55)

    Direct measurement of tree height provides different results on the assessment of LiDAR accuracy

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    open8noopenSibona, Emanuele; Vitali, Alessandro; Meloni, Fabio; Caffo, Lucia; Dotta, Alberto; Lingua, Emanuele; Motta, Renzo; Garbarino, MatteoSibona, Emanuele; Vitali, Alessandro; Meloni, Fabio; Caffo, Lucia; Dotta, Alberto; Lingua, Emanuele; Motta, Renzo; Garbarino, Matte

    St. Lucia joint annual report 2007

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    Galaxy Formation Theory

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    We review the current theory of how galaxies form within the cosmological framework provided by the cold dark matter paradigm for structure formation. Beginning with the pre-galactic evolution of baryonic material we describe the analytical and numerical understanding of how baryons condense into galaxies, what determines the structure of those galaxies and how internal and external processes (including star formation, merging, active galactic nuclei etc.) determine their gross properties and evolution. Throughout, we highlight successes and failings of current galaxy formation theory. We include a review of computational implementations of galaxy formation theory and assess their ability to provide reliable modelling of this complex phenomenon. We finish with a discussion of several "hot topics" in contemporary galaxy formation theory and assess future directions for this field.Comment: 58 pages, to appear in Physics Reports. This version includes minor corrections and a handful of additional reference

    Carbon portfolio management

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    The aim of the European Union's Emissions Trading Scheme (EU ETS) is that by 2020, emissions from sectors covered by the EU ETS will be 21% lower than in 2005. In addition to large CO 2 emitting companies covered by the scheme, other participants have entered the market with a view of using emission allowances for the diversification of their investment portfolios. The performance of this asset as a stand alone investment and its portfolio diversification implications will be investigated in this paper. Our results indicate that the market views Phases 1, 2, and 3 European Union allowance futures as unattractive as stand alone investments. In a portfolio context, in Phase 1, once the short-selling option is added, there are considerable portfolio benefits. However, our results indicate that these benefits only existed briefly during the pilot stage of the EU ETS. There is no evidence to suggest portfolio diversification benefits exist for Phase 2 or the early stages of Phase 3

    Equilibrium statistical mechanics for incomplete nonextensive statistics

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    The incomplete nonextensive statistics in the canonical and microcanonical ensembles is explored in the general case and in a particular case for the ideal gas. By exact analytical results for the ideal gas it is shown that taking the thermodynamic limit, with z=q/(1q)z=q/(1-q) being an extensive variable of state, the incomplete nonextensive statistics satisfies the requirements of equilibrium thermodynamics. The thermodynamical potential of the statistical ensemble is a homogeneous function of the first degree of the extensive variables of state. In this case, the incomplete nonextensive statistics is equivalent to the usual Tsallis statistics. If zz is an intensive variable of state, i.e. the entropic index qq is a universal constant, the requirements of the equilibrium thermodynamics are violated.Comment: 7 page

    The origin of redshift asymmetries: How LambdaCDM explains anomalous redshift

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    Several authors have found a statistically significant excess of galaxies with higher redshifts relative to the group centre, so-called discordant redshifts, in particular in groups where the brightest galaxy, identified in apparent magnitudes, is a spiral. Our aim is to explain the observed redshift excess. We use a semi-analytical galaxy catalogue constructed from the Millennium Simulation to study redshift asymmetries in spiral-dominated groups in the Lambda cold dark matter (LambdaCDM) cosmology. We show that discordant redshifts in small galaxy groups arise when these groups are gravitationally unbound and the dominant galaxy of the group is misidentified. The redshift excess is especially significant when the apparently brightest galaxy can be identified as a spiral, in full agreement with observations. On the other hand, the groups that are gravitationally bound do not show a significant redshift asymmetry. When the dominant members of groups in mock catalogues are identified by using the absolute B-band magnitudes, our results show a small blueshift excess. This result is due to the magnitude limited observations that miss the faint background galaxies in groups. When the group centre is not correctly identified it may cause the major part of the observed redshift excess. If the group is also gravitationally unbound, the level of the redshift excess becomes as high as in observations. There is no need to introduce any "anomalous" redshift mechanism to explain the observed redshift excess. Further, as the Friends-of-Friends percolation algorithm picks out the expanding parts of groups, in addition to the gravitationally bound group cores, group catalogues constructed in this way cannot be used as if the groups are purely bound systems.Comment: Accepted for publication in A&

    I\u27m Comin\u27, Pa

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    Fiction by Lucia Walto

    Reconciling with the Past: Ana Lucia Araujo’s Lecture on Coming to Terms with the Past When Monuments Are Taken Down

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    On Thursday, November 2nd, Howard University History Professor Ana Lucia Araujo visited Gettysburg College to give a lecture titled “Slavery, Memory, and Reparations: Coming to Terms with the Past When Monuments Are Taken Down.” The historian, author, and professor talked about the history of slavery as well as the concepts of memory and reparations. One form of reparations discussed recently has been the removal of Confederate monuments in the United States, which has been heavily debated for years. [excerpt

    Formation, Evolution and Properties of Isolated Field Elliptical Galaxies

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    [Abridged] We study the properties, evolution and formation mechanisms of isolated field elliptical galaxies. We create a mock catalogue of isolated field elliptical galaxies from the Millennium Simulation Galaxy Catalogue, and trace their merging histories. The formation, identity and assembly redshifts of simulated isolated and non-isolated elliptical galaxies are studied and compared. Observational and numerical data are used to compare age, mass, and the colour-magnitude relation. Our results, based on simulation data, show that almost seven per cent of all elliptical galaxies brighter than -19mag in B-band can be classified as isolated field elliptical galaxies. Isolated field elliptical galaxies show bluer colours than non-isolated elliptical galaxies and they appear younger, in a statistical sense, according to their mass weighted age. Isolated field elliptical galaxies also form and assemble at lower redshifts compared to non-isolated elliptical galaxies. About 46 per cent of isolated field elliptical galaxies have undergone at least one major merging event in their formation history, while the same fraction is only about 33 per cent for non-isolated ellipticals. The mean time of the last major merging is z = 0.6 or 6 Gyrs ago for isolated ellipticals, while non-isolated ellipticals experience their last major merging significantly earlier at z = 1.1 or 8 Gyrs ago. After inspecting merger trees of simulated isolated field elliptical galaxies, we conclude that three different, yet typical formation mechanisms can be identified: solitude, coupling and cannibalism. Our results also predict a previously unobserved population of blue, dim and light galaxies that fulfill observational criteria to be classified as isolated field elliptical galaxies. This separate population comprises about 26 per cent of all IfEs.Comment: Accepted for publication in MNRAS, 19 pages, 16 figure
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