909 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)

    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

    Truly unentangled photon pairs without spectral filtering

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    We demonstrate that an integrated silicon microring resonator is capable of efficiently producing photon pairs that are completely unentangled; such pairs are a key component of heralded single photon sources. A dual-channel interferometric coupling scheme can be used to independently tune the quality factors associated with the pump and signal and idler modes, yielding a biphoton wavefunction with Schmidt number arbitrarily close to unity. This will permit the generation of heralded single photon states with unit purity.Comment: 5 pages, 3 figure

    Negativity vs Entropy in Entanglement Witnessing

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    In this work, we prove that while all measures of mixedness can be used to witness entanglement, no measure of mixedness is more sensitive than the negativity of the partial transpose. However, computing either the negativity or differences between von Neumann entropies to witness entanglement requires complete knowledge of the joint density matrix (and is therefore not practical at high dimension). In light of this, we examine joint vs marginal purities as a witness of entanglement, (which can be obtained directly through interference measurements) and find that comparing purities is actually more sensitive at witnessing entanglement than using von Neumann entropies while also providing tight upper and lower bounds to it in the high-entanglement limit.Comment: 4 pages, 1 figur
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