1,327 research outputs found

    Dactylorhiza elata, Stately Dactylorhiza

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    Mediterranean regional assessment: Near Threatened (NT) The species is found from southwestern Europe and northwestern Africa. In two countries within the Mediterranean distribution (France and Portugal) populations or habitat of this species have declined by more than 30% over three generations. In another two countries (Algeria and Morocco) a similar decline is suspected but cannot yet be confirmed, and in Spain populations appear to be relatively abundant however there is no information on population trends. Elsewhere the species is known only from singlesites in Sardinia and Tunisia. whilst the extent of occurrence is very large, the area of occupancy (AOO) is possibly restricted however distribution data are inadequate to confirm the AOO. Therefore whilst the rate of decline cannot be measured throughout the range of the species, the Mediterranean population decline is confirmed, it is ongoing and is not reversible, consequently this species is close to classification as Vulnerable (A2c and A4c). Further to this, if monitoring data become available to provide an indication of population trends in Spain and these show that it is in decline then it is clear that the species should be considered threatened at both the Mediterranean and global scales. This species is therefore classed as Near Threatened, approaching Vulnerable (A2c+4c)

    On-Chip Quantum Interference from a Single Silicon Ring Resonator Source

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    Here we demonstrate quantum interference of photons on a Silicon chip produced from a single ring resonator photon source. The source is seamlessly integrated with a Mach-Zehnder interferometer, which path entangles degenerate bi-photons produced via spontaneous four wave mixing in the Silicon ring resonator. The resulting bi-photon N00N state is controlled by varying the relative phase of the integrated Mach-Zehnder interferometer, resulting in high two-photon interference visibilities of V~96%. Furthermore, we show that the interference can be produced using pump wavelengths tuned to all of the ring resonances accessible with our tunable lasers (C+L band). This work is a key demonstration towards the simplified integration of multiple photon sources and quantum circuits together on a monolithic chip, in turn, enabling quantum information chips with much greater complexity and functionality

    Cross-border Business in the European Union and Statutory Disclosure Requirements: Using IT as a Catalyst for Further Market Integration

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    This paper highlights the gap between the opportunities for EU-companies to fully exploittheir freedom of establishment on the one hand and the obstacles flowing from the mainly nationalorganisation of information filing requirements through business registers on the other hand. Fromthe point of view of companies, this gap partly neutralises the efforts replayed both in EU regulationand ECJ jurisprudence to guarantee the freedom of establishment. Companies are not only oftenobliged to file the same information in different countries but, due to the lack of information sharingbetween the countries in which they are established, investors, creditors and other stakeholders maysuffer information asymmetries. We analyse the possible legal approaches towards organising thefiling of information in a network model. The design of a technical solution to improve the crossbordersharing of corporate data in order to decrease administrative burdens on the freedom lies atthe heart of the BRITE project. BRITE wishes to increase the interoperability of business registers,not only with a view to facilitating the cross-border establishment of companies, but also as a toolfor other users (including public authorities) who can benefit from the better dissemination of publiccompany data and the possibility to aggregate data at a European level. We submit that the Europeanlawmakers have not yet fully exploited the possibilities offered by linking national publicinformation systems into networks, although the Transparency Directive does envisage a networkapproach as regards the dissemination of company and financial information by listed companies

    Geodesic and Path Motion in the Nonsymmetric Gravitational Theory

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    We study the problem of test-particle motion in the Nonsymmetric Gravitational Theory (NGT) assuming the four-velocity of the particle is parallel-transported along the trajectory. The predicted motion is studied on a static, spherically symmetric background field, with particular attention paid to radial and circular motions. Interestingly, it is found that the proper time taken to travel between any two non-zero radial positions is finite. It is also found that circular orbits can be supported at lower radii than in General Relativity for certain forms of motion. We present three interactions which could be used as alternate methods for coupling a test-particle to the antisymmetric components of the NGT field. One of these takes the form of a Yukawa force in the weak-field limit of a static, spherically symmetric field, which could lead to interesting phenomenology.Comment: 17 pages, REVTeX 3.0 with amssymb.st

    Homothetic Wyman Spacetimes

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    The time-dependent, spherically symmetric, Wyman sector of the Unified Field Theory is shown to be equivalent to a self-gravitating scalar field with a positive-definite, repulsive self-interaction potential. A homothetic symmetry is imposed on the fundamental tensor, and the resulting autonomous system is numerically integrated. Near the critical point (between the collapsing and non-collapsing spacetimes) the system displays an approximately periodic alternation between collapsing and dispersive epochs.Comment: 15 pages with 6 figures; requires amsart, amssymb, amsmath, graphicx; formatted for publication in Int. J. Mod. Phys.
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