Beschrijving zandbalans Westerschelde en monding

Voor de beheerder van het Schelde estuarium, Rijkswaterstaat directie Zeeland, is het belangrijk om het bagger- en stortbeleid en het zandwinbeleid zo optimaal mogelijk in te richten. Hiertoe is inzicht in de zandhuishouding in zowel de Westerschelde als de monding gewenst. Een instrument om dat inzicht te verkrijgen is een historische zandbalans. In dit rapport wordt voor de Westerschelde en de monding (zowel het Nederlandse deel als het Belgische deel) de interne zandhuishouding opgesteld. Hieruit wordt vervolgens de zandbalans opgesteld, waarbij de \u91natuurlijke\u92 zanduitwisselingen tussen verschillende gebieden wordt bepaald, rekening houdend met de ingrepen (baggeren, storten en zandwinning) van de mens. Met de zandbalans is de import of export van zand van de Westerschelde en de monding bepaald. Daarnaast zijn ook de invloed van zeespiegelstijging en de 18,6 jarige cyclus in het getij, de zogenaamde autonome ontwikkelingen, onderzocht. Gezien het belang van de uitkomsten van de studie voor het toekomstige beleid is tenslotte ook de invloed van onzekerheden in de gebruikte gegevens en in de gebruikte aannames op de die uitkomsten bepaald. De studie toont aan dat de Westerschelde eind jaren \u9280 van de vorige eeuw omgeslagen is van een zandimporterend naar een zandexporterend systeem. Ook de monding is vanaf die periode exporterend, echter hebben onzekerheden in de gegevens in het Belgische deel van de monding kwantitatief invloed op deze conclusie. Daarnaast wijst de zandbalans sinds 1997 op een toenemende zandexport vanuit de Westerschelde en een toename van het sedimenttransport van het westelijke naar het oostelijke deel van de Westerschelde. De autonome ontwikkelingen hebben geen aantoonbare invloed op de zandhuishouding in de Westerschelde: uit de lineaire trend kan geen duidelijke invloed op de zandbalans worden vastgesteld. Door middel van statistische analyse (bepaling van de correlatie) is geen significante relatie gebleken tussen de 18,6 jarige cyclus in het getij en de gemeten volumeveranderingen. De invloed van onzekerheden van gegevens en aannames op de uitkomsten van de zandbalans zijn weliswaar aanwezig, maar brengen geen verandering in het beeld dat de Westerschelde exporterend is. Wel verschuift het moment waarop de omslag van import naar export optreedt. Het rapport besluit met een aantal praktische aanbevelingen voor het verbeteren van de zandbalansen die in de volgende jaren gemaakt zullen worden. De meeste aanbevelingen hebben betrekking op het verbeteren van de betrouwbaarheid en beschikbaarheid van (historische en toekomstige) gegevens in het Belgische deel van de monding

Biostratigraphic and magnetostratigraphic synthesis of the Celebes and Sulu Seas, Leg 124

During ODP Leg 124, late middle Eocene to Quaternary sediment sequences were recovered from 13 holes drilled at five sites in the Celebes and Sulu basins. Paleomagnetic measurements and biostratigraphic studies using calcareous nannofossils, planktonic and benthic foraminifers, radiolarians, and diatoms were completed and summarized here. Two Neogene sediment sections recovered in the Sulu Basin yielded excellent core recoveries and magnetic reversal records, allowing direct magnetobiostratigraphic correlations for the Pliocene and Quaternary at Site 768 and for the middle Miocene to Quaternary at Site 769. The interpolated ages of biohorizons are not consistent between sites and only a few of them are in good agreement with previous calibrations. The differences may be the results of redeposition by turbidity currents and selective dissolution of key fossils

INSPECTION SHOP: PLAN TO PROVIDE UNCERTAINTY ANALYSIS WITH MEASUREMENTS

The LLNL inspection shop is chartered to make dimensional measurements of components for critical programmatic experiments. These measurements ensure that components are within tolerance and provide geometric details that can be used to further refine simulations. For these measurements to be useful, they must be significantly more accurate than the tolerances that are being checked. For example, if a part has a specified dimension of 100 millimeters and a tolerance of 1 millimeter, then the precision and/or accuracy of the measurement should be less than 1 millimeter. Using the ''10-to-1 gaugemaker's rule of thumb'', the desired precision of the measurement should be less than 100 micrometers. Currently, the process for associating measurement uncertainty with data is not standardized, nor is the uncertainty based on a thorough uncertainty analysis. The goal of this project is to begin providing measurement uncertainty statements with critical measurements performed in the inspection shop. To accomplish this task, comprehensive knowledge about the underlying sources of uncertainty for measurement instruments need to be understood and quantified. Moreover, measurements of elemental uncertainties for each physical source need to be combined in a meaningful way to obtain an overall measurement uncertainty

The evolution of developmental programs : a case study in the gastropod mollusc Patella vulgata

At the interface between evolutionary biology and developmental biology is the so-called field of evolutionary developmental biology (evo-devo in short). This field asks how different adult animals (species) came into being by heritable changes during their embryonic development. One way to study this question is a comparative analysis of genes that are important for the development of different species. Many genes appear to be conserved during evolution, i.e. the same gene can have a comparable role during the development of very different species. This developmental genetic unity underlying very different animals has puzzled evolutionists as well as developmental biologists. It has led to two main questions: -what aspects of gene function can be considered as conserved, thus evolutionary very ancient, perhaps even ancestral to metazoans (or bilaterians)? -how can such different animals be generated from such similar sets of genes? This study is involved with the phylum Mollusca (snails, slugs, octopuses and the like). Very little is known on the genetics of early development of molluscs. Data on the role of genes during the development of molluscan animals, therefore, is likely to provide new insights and will contribute to answering the abovementioned questions. The study organism of this thesis is the gastropod mollusk Patella vulgata. Orthologs (gene homologs) of seven genes are described: snail, twist, orthodenticle, orthopedia, engrailed, dpp en hedgehog. The question asked is in this thesis is: what insights do we obtain when we broaden our comparative analysis of the role developmental genes play to molluscs? The research on these seven genes has given a number of new insights. One is a better understanding on what role of these genes has been conserved during evolution. It is very likely that the common evolutionary ancestor to all animals already had these genes with these particular functions. Despite the fact that many animals have genes in common, often with the same function, not all animals are alike. The research described in this thesis contributed to our understanding of this apparent paradox. A gene can have a certain function, which allows it to contribute to the development of very different structures or organs. For example, the engrailed gene is involved in generating boundaries between groups of cells. During development, cells expressing the engrailed gene form a compartment excluding other, neighbouring cells that form another compartment (and do not express engrailed). Both compartments become different parts of the adult organism. In the fruitfly, for example, engrailed plays a role in boundary formation between segments, the building blocks of the body of the fly. But also in molluscs, such as Patella, engrailed is involved in boundary formation, namely between cells that form the shell and the surrounding cells that do not contribute to shell formation. The fact that such very different structures such as segments in flies and shells in snails use the same gene for their formation can thus be explained by the fact that engrailed is a boundary formation gene. This is the way evolution creates different animals from the same set of genes: by recombining similar building blocks in new ways, new structures can be formed, a phenomenon called tinkering (or bricolage)

The effect of seawater carbonate chemistry on the stable isotope composition of Cibicidoides wuellerstorfi and other Cibicidoides species

The δ13C composition of Cibicidoides wuellerstorfi and other Cibicidoides spp is an important tool to reconstruct past changes in the deep ocean carbon cycle. The species are expected to match the δ13C of ambient dissolved inorganic carbon (DIC), although it has been recognized that substantial offsets can occur. Here, I present a compilation of modern δ13C and δ18O data for named Cibicidoides species in combination with fully resolved carbonate chemistry at each core location. The data show for C. wuellerstorfi that the offset from the expected value in both carbon (∆13C) and oxygen (∆18O) is correlated with seawater carbonate chemistry. The result is comparable to, but not identical with, published culture experiments in which marine organisms were grown under variable pH-conditions. Overall, ∆13C in C. wuellerstorfi correlates positively with carbonate saturation, [DIC], and temperature. The three variables together explain 47.1% of the variation in ∆13C. The trend for ∆18O is similar, except that the effect of temperature has been removed through correction with a published δ18O-temperature equation. Up to 35% of the remaining variation in ∆18O can be explained by ambient carbonate chemistry. Data for other named Cibicidoides species are broadly similar, but are too sparse for a detailed analysis. The results indicate that strongly negative ∆13C occurs predominantly in the deep Atlantic in response to a combination of low [DIC], low temperature, and undersaturation within the lysocline. Implications for paleoceanographic reconstructions are discussed

Assessing diversity of the female urine microbiota by high throughput sequencing of 16S rDNA amplicons

<p>Abstract</p> <p>Background</p> <p>Urine within the urinary tract is commonly regarded as "sterile" in cultivation terms. Here, we present a comprehensive in-depth study of bacterial 16S rDNA sequences associated with urine from healthy females by means of culture-independent high-throughput sequencing techniques.</p> <p>Results</p> <p>Sequencing of the V1V2 and V6 regions of the 16S ribosomal RNA gene using the 454 GS FLX system was performed to characterize the possible bacterial composition in 8 culture-negative (<100,000 CFU/ml) healthy female urine specimens. Sequences were compared to 16S rRNA databases and showed significant diversity, with the predominant genera detected being <it>Lactobacillus</it>, <it>Prevotella </it>and <it>Gardnerella</it>. The bacterial profiles in the female urine samples studied were complex; considerable variation between individuals was observed and a common microbial signature was not evident. Notably, a significant amount of sequences belonging to bacteria with a known pathogenic potential was observed. The number of operational taxonomic units (OTUs) for individual samples varied substantially and was in the range of 20 - 500.</p> <p>Conclusions</p> <p>Normal female urine displays a noticeable and variable bacterial 16S rDNA sequence richness, which includes fastidious and anaerobic bacteria previously shown to be associated with female urogenital pathology.</p

A genome-wide analysis of nonribosomal peptide synthetase gene clusters and their peptides in a Planktothrix rubescens strain

<p>Abstract</p> <p>Background</p> <p>Cyanobacteria often produce several different oligopeptides, with unknown biological functions, by nonribosomal peptide synthetases (NRPS). Although some cyanobacterial NRPS gene cluster types are well described, the entire NRPS genomic content within a single cyanobacterial strain has never been investigated. Here we have combined a genome-wide analysis using massive parallel pyrosequencing ("454") and mass spectrometry screening of oligopeptides produced in the strain <it>Planktothrix rubescens </it>NIVA CYA 98 in order to identify all putative gene clusters for oligopeptides.</p> <p>Results</p> <p>Thirteen types of oligopeptides were uncovered by mass spectrometry (MS) analyses. Microcystin, cyanopeptolin and aeruginosin synthetases, highly similar to already characterized NRPS, were present in the genome. Two novel NRPS gene clusters were associated with production of anabaenopeptins and microginins, respectively. Sequence-depth of the genome and real-time PCR data revealed three copies of the microginin gene cluster. Since NRPS gene cluster candidates for microviridin and oscillatorin synthesis could not be found, putative (gene encoded) precursor peptide sequences to microviridin and oscillatorin were found in the genes <it>mdn</it>A and <it>osc</it>A, respectively. The genes flanking the microviridin and oscillatorin precursor genes encode putative modifying enzymes of the precursor oligopeptides. We therefore propose ribosomal pathways involving modifications and cyclisation for microviridin and oscillatorin. The microviridin, anabaenopeptin and cyanopeptolin gene clusters are situated in close proximity to each other, constituting an oligopeptide island.</p> <p>Conclusion</p> <p>Altogether seven nonribosomal peptide synthetase (NRPS) gene clusters and two gene clusters putatively encoding ribosomal oligopeptide biosynthetic pathways were revealed. Our results demonstrate that whole genome shotgun sequencing combined with MS-directed determination of oligopeptides successfully can identify NRPS gene clusters and the corresponding oligopeptides. The analyses suggest independent evolution of all NRPS gene clusters as functional units. Our data indicate that the <it>Planktothrix </it>genome displays evolution of dual pathways (NRPS and ribosomal) for production of oligopeptides in order to maximize the diversity of oligopeptides with similar but functional discrete bioactivities.</p

Feasting and mobility in Iron Age Ireland: multi-isotope analysis reveals the vast catchment of Navan Fort, Ulster

Navan Fort is an iconic prehistoric Irish ceremonial centre and the legendary capital of Ulster. The fort has produced an exceptional pig-dominated faunal assemblage that also contained a barbary macaque skull. Dating from the 4th to 1st century BC, it is likely to be a ceremonial feasting centre that may have drawn people and their animals from across Ulster and beyond. This study uses a multi-isotope (87Sr/86Sr, δ34S, δ13C, δ15N) approach to identify non-local animals and reconstruct site catchment. New biosphere mapping means that isotope data can be more confidently interpreted and the combination of strontium and sulphur analysis has the potential to estimate origins. In the absence of human remains, fauna provide the best proxy for human movement. Results for the 35 analysed animals are wide-ranging, especially in terms of strontium (0.707–0.715), which has the largest range for an Irish site. Sulphur values are more restricted (13.1‰−17.1‰) but are high in the context of British and Irish data. Results provide clear evidence for animals (and thus people) coming from across Ulster and beyond, demonstrating the site’s wide catchment. Navan Fort was clearly a major ceremonial centre with far-reaching influence and hosted feasts that drew people and animals from afar