Onderzoekprogramma ecologisch herstel Eems-Dollard

Al vele jaren spelen er discussies over de ecologische kwaliteit van het Nederlandse Waddengebied. Vijftig jaar geleden speelde de mogelijke inpoldering. Contaminanten als dieldrin en PCB’s waren een belangrijk thema in de jaren erna en vanaf de jaren ’90 tot (deels) nu toe is schelpdiervisserij onderwerp van studie waarbij ook gesteld wordt dat er een verzanding van het systeem optreedt. Streefdoelen voor de waterkwaliteit zijn in de Kaderrichtlijn Water vastgelegd, het gehele Waddengebied (inclusief dus de Eems-Dollard) is aangewezen als Vogel- en Habitatrichtlijngebied, en is daarmee Natura2000-gebied. Hiermee zijn vele kwaliteitsdoelen geformuleerd, waarmee de beheerder verplicht wordt maatregelen te treffen opdat daar aan voldaan wordt

Natuurgrenzen in de Waddenzee: een verkenning voor beleid en beheer

Het begrip natuurgrenzen wordt de laatste jaren regelmatig gebruikt in het kader van beleidsontwikkeling. In de praktijk blijkt dat het niet eenvoudig is om het begrip zodanig inhoud te geven dat vergunningverlening er op gebaseerd kan worden. Mede omdat er verwarring en overlap was er met het begrip gebruiksgrens. Geconcludeerd wordt dat er wel degelijk natuurgrenzen bestaan, maar voor het vaststellen daarvan is het noodzakelijk eerst goed te definiëren over welk type natuur we het hebben. Daarom wordt de term natuurtype geïntroduceerd

Weak and strong electronic correlations in Fe superconductors

In this chapter the strength of electronic correlations in the normal phase of Fe-superconductors is discussed. It will be shown that the agreement between a wealth of experiments and DFT+DMFT or similar approaches supports a scenario in which strongly-correlated and weakly-correlated electrons coexist in the conduction bands of these materials. I will then reverse-engineer the realistic calculations and justify this scenario in terms of simpler behaviors easily interpreted through model results. All pieces come together to show that Hund's coupling, besides being responsible for the electronic correlations even in absence of a strong Coulomb repulsion is also the origin of a subtle emergent behavior: orbital decoupling. Indeed Hund's exchange decouples the charge excitations in the different Iron orbitals involved in the conduction bands thus causing an independent tuning of the degree of electronic correlation in each one of them. The latter becomes sensitive almost only to the offset of the orbital population from half-filling, where a Mott insulating state is invariably realized at these interaction strengths. Depending on the difference in orbital population a different 'Mottness' affects each orbital, and thus reflects in the conduction bands and in the Fermi surfaces depending on the orbital content.Comment: Book Chapte

Two-site dynamical mean-field theory

It is shown that a minimum realization of the dynamical mean-field theory (DMFT) can be achieved by mapping a correlated lattice model onto an impurity model in which the impurity is coupled to an uncorrelated bath that consists of a single site only. The two-site impurity model can be solved exactly. The mapping is approximate. The self-consistency conditions are constructed in a way that the resulting ``two-site DMFT'' reduces to the previously discussed linearized DMFT for the Mott transition. It is demonstrated that a reasonable description of the mean-field physics is possible with a minimum computational effort. This qualifies the simple two-site DMFT for a systematic study of more complex lattice models which cannot be treated by the full DMFT in a feasible way. To show the strengths and limitations of the new approach, the single-band Hubbard model is investigated in detail. The predictions of the two-site DMFT are compared with results of the full DMFT. Internal consistency checks are performed which concern the Luttinger sum rule, other Fermi-liquid relations and thermodynamic consistency.Comment: LaTeX, 14 pages, 8 eps figures included, Phys. Rev. B (in press

Reading and numeracy attainment of children reported to child protection services: A population record linkage study controlling for other adversities

Background: Maltreated children are at risk of poor educational outcomes, but also experience greater individual, family, and neighbourhood adversities that may obscure an understanding of relationships between child protection involvement and educational attainment. Objective: To examine associations between child protection involvement and 3rd- and 5th-grade reading and numeracy attainment, while controlling multiple other adversities. Participants and Setting Participants were 56,860 Australian children and their parents from the New South Wales Child Development Study with linked multi-agency records. Methods: Multinomial logistic regressions examined associations between level of child protection involvement (Out-Of-Home Care [OOHC] placement; substantiated Risk Of Significant Harm [ROSH]; unsubstantiated ROSH; non-ROSH; and no child protection report) and standardised tests of 3rd- and 5th-grade reading and numeracy. Fully adjusted models controlled demographic, pregnancy, birth, and parental factors, and early (kindergarten) developmental vulnerabilities on literacy and numeracy, and other developmental domains (social, emotional, physical, communication). Results: All children with child protection reports were more likely to attain below average, and less likely to attain above average, 3rd- and 5th-grade reading and numeracy, including children with reports below the ROSH threshold. Children with substantiated ROSH reports who were not removed into care demonstrated the worst educational attainment, with some evidence of protective effects for children in OOHC. Conclusions: A cross-agency response to supporting educational attainment for all children reported to child protection services is required, including targeted services for children in OOHC or with substantiated ROSH reports, and referral of vulnerable families (unsubstantiated and non-ROSH cases) to secondary service organisations (intermediate intervention).Kristin R.Laurens, Fahkrul Islam, Maina Kariuki, Felicity Harris, Marilyn Chilvers ... Sally A.Brinkman ... et al

Spectral and transport properties of doped Mott-Hubbard systems with incommensurate magnetic order

We present spectral and optical properties of the Hubbard model on a two-dimensional square lattice using a generalization of dynamical mean-field theory to magnetic states in finite dimension. The self-energy includes the effect of spin fluctuations and screening of the Coulomb interaction due to particle-particle scattering. At half-filling the quasiparticles reduce the width of the Mott-Hubbard `gap' and have dispersions and spectral weights that agree remarkably well with quantum Monte Carlo and exact diagonalization calculations. Away from half-filling we consider incommensurate magnetic order with a varying local spin direction, and derive the photoemission and optical spectra. The incommensurate magnetic order leads to a pseudogap which opens at the Fermi energy and coexists with a large Mott-Hubbard gap. The quasiparticle states survive in the doped systems, but their dispersion is modified with the doping and a rigid band picture does not apply. Spectral weight in the optical conductivity is transferred to lower energies and the Drude weight increases linearly with increasing doping. We show that incommensurate magnetic order leads also to mid-gap states in the optical spectra and to decreased scattering rates in the transport processes, in qualitative agreement with the experimental observations in doped systems. The gradual disappearence of the spiral magnetic order and the vanishing pseudogap with increasing temperature is found to be responsible for the linear resistivity. We discuss the possible reasons why these results may only partially explain the features observed in the optical spectra of high temperature superconductors.Comment: 22 pages, 18 figure

Comprehensive evaluation of methods to assess overall and cell-specific immune infiltrates in breast cancer

Background: Breast cancer (BC) immune infiltrates play a critical role in tumor progression and response to treatment. Besides stromal tumor infiltrating lymphocytes (sTILs) which have recently reached level 1B evidence as a prognostic marker in triple negative BC, a plethora of methods to assess immune infiltration exists, and it is unclear how these compare to each other and if they can be used interchangeably. Methods: Two experienced pathologists scored sTIL, intra-tumoral TIL (itTIL), and 6 immune cell types (CD3+, CD4+, CD8+, CD20+, CD68+, FOXP3+) in the International Cancer Genomics Consortium breast cancer cohort using hematoxylin and eosin-stained (n = 243) and immunohistochemistry-stained tissue microarrays (n = 254) and whole slides (n = 82). The same traits were evaluated using transcriptomic- and methylomic-based deconvolution methods or signatures. Results: The concordance correlation coefficient (CCC) between pathologists for sTIL was very good (0.84) and for cell-specific immune infiltrates slightly lower (0.63-0.66). Comparison between tissue microarray and whole slide pathology scores revealed systematically higher values in whole slides (ratio 2.60-5.98). The Spearman correlations between microscopic sTIL and transcriptomic- or methylomic-based assessment of immune infilt