Verkenning van mogelijkheden voor mosselteelt op Noordzee

In dit rapport wordt nagegaan of er wereldwijd zodanig perspectiefrijke experimenten met invang dan wel kweek van mosselen in het open zee milieu (offshore) plaatsvinden, of dat er reeds volledig commercieel draaiende mosselculturen op open zee bestaan. Indien dit het geval is wordt bezien of hiervan gebruik kan worden gemaakt voor de innovatie van de Nederlandse mosselsector. Wij achten de studies het meest relevant voor het toepassen van installaties als de fysische omstandigheden (diepte, golfhoogte en stroomsnelheid) zoveel als mogelijk overeenkomen met die in de Noordzee

Groei en begrazing van mosselzaad, primaire productie en picoplankton in de Waddenzee: Technisch Rapport project Meerjarig effect- en productiemetingen aan MZI's in de Westerlijke Waddenzee, Oosterschelde en Voordelta

In het kader van het project: “Meerjarige effectmetingen aan MZI’s in de Westelijke Waddenzee en de Oosterschelde”, uitgevoerd door IMARES in opdracht van het Ministerie van LNV (thans EZ), zijn er in 2010 tot en met 2013 veldmetingen verricht bij een MZI. Centrale vraag binnen deelproject 1 betreft de mogelijke invloed van MZI’s op de draagkracht van de Waddenzee en de Oosterschelde. In dit rapport worden de resultaten gepresenteerd van het onderzoek aan de MZI’s in de Waddenzee

The Three Dimensions of Archaeology - Introduction

This volume brings together presentations from two sessions organized for the XVII World UISPP Conference that was held from 1-7 September 2014 in Burgos (Spain). The sessions are: The scientific value of 3D archaeology, organised by Hans Kamermans, Chiara Piccoli and Roberto Scopigno, and Detecting the Landscape(s) – Remote Sensing Techniques from Research to Heritage Management, organised by Axel Posluschny and Wieke de Neef. The common thread amongst the papers presented here is the application of digital recording techniques to enhance the documentation and analysis of the spatial component intrinsically present in archaeological data. For a long time the capturing of the third dimension, the depth, the height or z-coordinate, was problematic. Traditionally, excavation plans and sections were documented in two dimensions. Objects were also recorded in two dimensions, often from different angles. Remote sensing images like aerial photographs were represented as flat surfaces. Although depth could be visualized with techniques such as stereoscopes, analysis of relief was troublesome. All this changed at the end of the last century with the introduction of computer based digitization technologies, 3D software, and digital near-surface sampling devices. The spatial properties of the multi-scale archaeological dataset can now be accurately recorded, analysed and presented. Relationships between artefacts can be clarified by visualizing the records in a three dimensional space, computer-based simulations can be made to test hypotheses on the past use of space, remote sensing techniques help in detecting previously hidden features of landscapes, thus shedding light on bygone land uses.  Digital Archaeolog

Shango businessplan: gecontroleerd schelpdierkweeksysteem, van zaad tot aan consumptiemossel; systeemontwerp, protocollen, technisch-economische haalbaarheid

Het natuurlijke aanbod van uitgangsmateriaal voor schelpdierteelt(zaad) vertoont jaarlijks sterke fluctuaties. Er is daarom behoefte aan nieuwe technieken ten behoeve van de zaadvoorziening. Een nieuwe techniek is productie van zaad op land in een hatchery/nursery Het project is gericht op de mossel (Mytilus Edulis) en het ontwikkelen en uittesten van een prototype hatchery/nursery met growout systemen. De technische beschrijving beperkt zich tot op systeemniveau, inclusief het programma van eisen voor de benodigde componenten. Tevens worden de operationele aspecten in protocollen weergegeven. Tenslotte wordt aan het eind een technisch-economische beschouwing gegeven. De kostprijs voor hatcheryzaad is nog vele malen te hoog t.o.v. bodemzaad en mosselzaadinvang

Dynamic IMF production in 24Mg+27Al^{24}Mg + ^{27}Al at intermediate energies

The azimuthal correlations and polar-angle distributions of intermediate-mass fragments (IMFs) produced in Mg+Al at 45 an 95 AMeV were studied. Measurements of $\alpha$-particles and IMFs with $3\le Z\le8$ emmitted in the mid-rapidity region for mid-central events were compared to IQMD results and results from a static-source model. A maximum in the azimuthal-correlation function at 180\degree\/ can not be described by independently emmitted particles. Momentum conservation of a small source as well as target-projectile correlations from IQMD show the same azimuthal correlations as the experimental data. The polar-angle distributions in the experimental data show a target-projectile seperation, thus giving evidence of dynamic IMF production.\\ {\it Keywords:} dynamic multifragmentation, IMF, IQMD, azimuthal correlations

Synaptic Transmission from Horizontal Cells to Cones Is Impaired by Loss of Connexin Hemichannels

In the vertebrate retina, horizontal cells generate the inhibitory surround of bipolar cells, an essential step in contrast enhancement. For the last decades, the mechanism involved in this inhibitory synaptic pathway has been a major controversy in retinal research. One hypothesis suggests that connexin hemichannels mediate this negative feedback signal; another suggests that feedback is mediated by protons. Mutant zebrafish were generated that lack connexin 55.5 hemichannels in horizontal cells. Whole cell voltage clamp recordings were made from isolated horizontal cells and cones in flat mount retinas. Light-induced feedback from horizontal cells to cones was reduced in mutants. A reduction of feedback was also found when horizontal cells were pharmacologically hyperpolarized but was absent when they were pharmacologically depolarized. Hemichannel currents in isolated horizontal cells showed a similar behavior. The hyperpolarization-induced hemichannel current was strongly reduced in the mutants while the depolarization-induced hemichannel current was not. Intracellular recordings were made from horizontal cells. Consistent with impaired feedback in the mutant, spectral opponent responses in horizontal cells were diminished in these animals. A behavioral assay revealed a lower contrast-sensitivity, illustrating the role of the horizontal cell to cone feedback pathway in contrast enhancement. Model simulations showed that the observed modifications of feedback can be accounted for by an ephaptic mechanism. A model for feedback, in which the number of connexin hemichannels is reduced to about 40%, fully predicts the specific asymmetric modification of feedback. To our knowledge, this is the first successful genetic interference in the feedback pathway from horizontal cells to cones. It provides direct evidence for an unconventional role of connexin hemichannels in the inhibitory synapse between horizontal cells and cones. This is an important step in resolving a long-standing debate about the unusual form of (ephaptic) synaptic transmission between horizontal cells and cones in the vertebrate retina

Evidence for giant quadrupole excitation in 208Pb by 200 MeV 12C scattering

In inelastic 12C scattering from 208Pb a peak, corresponding in excitation energy, width and strength to the well-known GQR is observed. The underlying broad continuum is probably due to 13C breakup rather than to excitation of giant resonances with L > 2