1,137 research outputs found

    Uitgesloten amateurs in het nieuwe landschap van de Nederlandse archeologie

    Get PDF
    Dit artikel gaat in op de bijdrage en rollen van amateurarcheologen . Beargumenteerd wordt dat een Nederlandse transformatie van het beleidssysteem dat verantwoordelijk is voor het behoud van archeologie, heeft bijgedragen aan de uitsluiting van de amateur-archeologen. Een aantal mechanismen die bijdragen aan de geslotenheid van het archeologisch beleidssysteem an aan de uitsluiting van de amateur-archeologen wordt geëxpliciteerd. Genoemde mechanismen zijn terug te vinden in vele contexten waarin burgers en overheden interagere

    The Riemann–Hilbert approach to strong asymptotics for orthogonal polynomials on [−1,1]

    Get PDF
    We consider polynomials that are orthogonal on [−1,1] with respect to a modified Jacobi weight (1− ) (1+ ) ( ), with , >−1 and real analytic and strictly positive on [−1,1]. We obtain full asymptotic expansions for the monic and orthonormal polynomials outside the interval [−1,1], for the recurrence coefficients and for the leading coefficients of the orthonormal polynomials. We also deduce asymptotic behavior for the Hankel determinants and for the monic orthogonal polynomials on the interval [−1,1]. For the asymptotic analysis we use the steepest descent technique for Riemann–Hilbert problems developed by Deift and Zhou, and applied to orthogonal polynomials on the real line by Deift, Kriecherbauer, McLaughlin, Venakides, and Zhou. In the steepest descent method we will use the Szegő function associated with the weight and for the local analysis around the endpoints ±1 we use Bessel functions of appropriate order, whereas Deift et al. use Airy functions

    Secure Coherent-state Quantum Key Distribution Protocols with Efficient Reconciliation

    Full text link
    We study the equivalence between a realistic quantum key distribution protocol using coherent states and homodyne detection and a formal entanglement purification protocol. Maximally-entangled qubit pairs that one can extract in the formal protocol correspond to secret key bits in the realistic protocol. More specifically, we define a qubit encoding scheme that allows the formal protocol to produce more than one entangled qubit pair per coherent state, or equivalently for the realistic protocol, more than one secret key bit. The entanglement parameters are estimated using quantum tomography. We analyze the properties of the encoding scheme and investigate its application to the important case of the attenuation channel.Comment: REVTeX, 11 pages, 2 figure

    Strong asymptotics for Cauchy biorthogonal polynomials with application to the Cauchy two--matrix model

    Get PDF
    We apply the nonlinear steepest descent method to a class of 3x3 Riemann-Hilbert problems introduced in connection with the Cauchy two-matrix random model. The general case of two equilibrium measures supported on an arbitrary number of intervals is considered. In this case, we solve the Riemann-Hilbert problem for the outer parametrix in terms of sections of a spinorial line bundle on a three-sheeted Riemann surface of arbitrary genus and establish strong asymptotic results for the Cauchy biorthogonal polynomials.Comment: 31 pages, 12 figures. V2; typos corrected, added reference

    De performatieve macht van mislukking; Moeizame implementatie van Natura 2000

    Get PDF
    Het Natura 2000-beleid heeft in Nederland tot veel kritiek geleid. Tijdens informatie- en inspraakavonden, in artikelen, op het internet en ook in politieke arena's is er voornamelijk in negatieve zin over gesproken. In dit artikel gaan we na wat implicaties zijn van deze negatieve ideeën en beeldvorming voor de implementatie van Natura 2000-beleid. (performatieve ~ wat wordt bewerkstelligd

    The importance of reflexivity in planning and design education

    Get PDF
    This is a special edition of a Wageningen University Working Papers in Evolutionary Governance Theory (EGT). EGT offers a new perspective on the way markets, institutions and societies evolve together. It can be of use to anyone interested in market and public sector reform, development, public administration, politics and law. Theoretically, the approach draws on a wide array of sources: institutional & development economics, systems theories, post- structuralism, actor- network theories, discourse theory, planning theory and legal studies. In this working paper we use the EGT perspective to make an argument for greater reflexivity in planning and design education. Reflexivity is understood as a sustained reflection on the positionality of knowledge and presented as an opportunity to strengthen the academic dimension of planning and design curricula. The planning and design curricula, we argue, cannot tackle these issues without a deeper and more systematic self-reflection, a reflection on the disciplines, their teaching, on the role of planners and designers in society. We will show how research and outreach can play a transformative role in the development and delivery of professional landscape architecture and planning curricula (see also www.governancetheory.com)

    Metabolic profiling of a transgenic Caenorhabditis elegans Alzheimer model

    Get PDF
    Despite decades of research, no early-onset biomarkers are currently available for Alzheimer’s disease, a cureless neurodegenerative disease afflicting millions worldwide. In this study, transgenic Caenorhabditis elegans were used to investigate changes in the metabolome after induced expression of amyloid-β. GC- and LC–MS-based platforms determined a total of 157 differential features. Some of these were identified using in-house (GC–MS) or public libraries (LC–MS), revealing changes in allantoin, cystathionine and tyrosine levels. Since C. elegans is far better suited to metabolomics studies than most other model systems, the accordance of these findings with vertebrate literature is promising and argues for further use of C. elegans as a model of human pathology in the study of AD

    The Measure of the Orthogonal Polynomials Related to Fibonacci Chains: The Periodic Case

    Full text link
    The spectral measure for the two families of orthogonal polynomial systems related to periodic chains with N-particle elementary unit and nearest neighbour harmonic interaction is computed using two different methods. The interest is in the orthogonal polynomials related to Fibonacci chains in the periodic approximation. The relation of the measure to appropriately defined Green's functions is established.Comment: 19 pages, TeX, 3 scanned figures, uuencoded file, original figures on request, some misprints corrected, tbp: J. Phys.

    Prevalence of anal fistulas in Europe: Systematic literature reviews and population-based database analysis

    Full text link
    Introduction: Despite the fact that perianal fistulas are associated with significant morbidity and impaired quality of life, their prevalence in Europe is unknown. The aim of this study was to estimate the prevalence of perianal fistulas in Europe, overall and according to etiology. Methods: Two independent literature reviews were performed using different search strategies to maximize the identification of potentially relevant studies. Data from relevant articles were used to estimate the prevalence of perianal fistulas in Europe. The robustness of the estimate was evaluated using data from a large population-based database from the UK. Results: A total of 26 studies provided epidemiological data on perianal fistulas, of which 16 provided suitable data to estimate the prevalence. Estimations using these data yielded a total prevalence of 1.69 per 10,000 population. Cryptoglandular infection and Crohn’s disease (CD) were the predominant etiologies, with prevalence rates at 0.86 and 0.76 per 10,000 population, respectively. Comparison of prevalence data from the UK population-based database with the European population resulted in a standardized prevalence estimate of all perianal fistulas of 1.83 per 10,000 population, confirming the robustness of the literaturebased estimate. Conclusion: Although in terms of incidence cryptoglandular fistulas were clearly predominant, the prevalence of fistulas in CD and cryptoglandular infection appeared more balanced. This is due to the longer duration and higher frequency of relapses of fistulas in CD. The estimated prevalence implies that perianal fistulas meet the criteria to be considered as a rare condition in Europe (prevalence less than 5 per 10,000 population).This study was funded by Takeda Pharmaceutical U.S.A., Inc. and TiGenix SA

    Continuous Variable Quantum Cryptography using Two-Way Quantum Communication

    Full text link
    Quantum cryptography has been recently extended to continuous variable systems, e.g., the bosonic modes of the electromagnetic field. In particular, several cryptographic protocols have been proposed and experimentally implemented using bosonic modes with Gaussian statistics. Such protocols have shown the possibility of reaching very high secret-key rates, even in the presence of strong losses in the quantum communication channel. Despite this robustness to loss, their security can be affected by more general attacks where extra Gaussian noise is introduced by the eavesdropper. In this general scenario we show a "hardware solution" for enhancing the security thresholds of these protocols. This is possible by extending them to a two-way quantum communication where subsequent uses of the quantum channel are suitably combined. In the resulting two-way schemes, one of the honest parties assists the secret encoding of the other with the chance of a non-trivial superadditive enhancement of the security thresholds. Such results enable the extension of quantum cryptography to more complex quantum communications.Comment: 12 pages, 7 figures, REVTe
    • …
    corecore