63 research outputs found
Sustainable alternative designs for the Tongzhou Bay Port: A design study at the potential of alternative reclamation configurations through a 'Building-with-Nature' approach, in preserving and creating valuable habitat based on two specialised coastal shorebird species at the Jiangsu coast
No full textOver the last decades, the People’s Republic of China experience large economic development, which have led to severe shortages of usable land. To counteract this, the Chinese central government promoted the development of coastal provinces by reclaiming large sections of coastal zones. One of these regions is Nantong Binhai Park or Tongzhou Bay on the Jiangsu coast. This region is characterized with large intertidal mudflats and tidal channels and has a high potential for the development of agri-aquaculture as well as the construction of a deep-sea port. However, these intertidal mudflats are a vital part of ecosystems and support numerous species, such as several endangered migratory shorebirds within the East Asian–Australasian Flyway. Acknowledging the importance of both port development and existing endangered ecosystems, a more integrated coastal design is needed. Possible solution could be found through the Building with Nature approach, in which natural processes and ecological needs are included in the design. This requires a good understanding of the governing processes as well as the requirements from society, ecology and engineering perspectives.In this thesis, a preliminary study was performed into a more sustainable alternative for the planned Tongzhou Bay Port, in which a basic connection was made between engineering and ecological point of view. A hydro-morphodynamic numerical model was made available and further developed for the modelling of the governing processes in the development of the intertidal mudflats at Tongzhou Bay. The model showed satisfactory results with respect to observations and net flow and transport features were closer analyzed. The different ecosystem types at Tongzhou Bay were quantified with ecotope classification and further validated with satellite-tracked data of two endangered shorebird species. Based on this validation, high-value ecotopes were determined based on these species and was used as an indication for the performance of alternative port configurations with respect to ecology.With a better understanding of the governing processes for the development of the intertidal mudflats and ecotopes, a series of alternative port designs were conceived through several design cycle iterations. Guiding principles were the preservation of high-value ecotopes, the enhancement of these area’s development and the potential area created for future port development by each variant. Results showed that by understanding natural transport and siltation patterns, not only could alternative port configurations lead to the preservation of existing high-value ecotopes, but a stronger development of these areas with respect to the natural development could be realized as well. The preliminary results of this thesis show the potential of more sustainable alternative port designs through the Building-with-Nature principle, in creating benefits for both economic and ecological development of Tongzhou Bay
Quantifying the Influence of Salt Marshes on Wave Run-Up on a Dike During Extreme Wave Conditions: An Experimental Study
No full textSalt Marshes are a coastal ecosystem which have numerous benefits as coastal defense such as wave attenuation and can adapt to sea level rise. Wave flume tests, using a scale model of a cross-section of a salt marsh adjacent to a dike, were conducted in the Hydraulic Laboratory, to quantify the effectiveness of such a salt marsh system as flood defense (part of the Living Dikes research program). This thesis focuses on the reduction in wave run-up due to salt marshes on the adjacent dike, with a focus on high water levels. The wave run-up was measured using video processing, using a newly created algorithm to track the water movement on the dike slope. The results show a significant reduction in wave run-up due to wave attenuation over the salt marsh, further dependent on the presence of vegetation and the water depth on top of the salt marsh. The measured wave run-up values show some differences with values acquired using the TAW/EurOtop wave run-up formula. There is a correlation found with the wave steepness, where waves with a lower wave steepness do match the equation, and show a larger deviation for increasingly higher wave steepnesses.Civil Engineering | Hydraulic Engineerin
Diatom response to mid-Holocene climate in three small Arctic lakes in northernmost Finnmark
Full text linkPalaeoclimatic reconstructions from lake sediment biological records can be challenging, due to variation in non-climatic factors, which alter ecosystem responses. To consider this, it is important to replicate a study regionally, so as to gain information on spatial variability of ecosystem response and the influence of site-specific conditions. Previous pollen-based palaeoclimatic records from three well-dated Arctic lake sites highlight the response of regional Scots Pine (Pinus sylvestris) and Mountain Birch (Betula pubescens ssp. czerepanovii) forest-tundra transition to Holocene climatic variability and suggest the northernmost Peninsulas of Finnmark to be climatically sensitive. This study analysed dated sediment sequences between c. 3970 and c. 6200 cal. yr BP from these three previously published shallow lakes: Liten Čap’pesjav’ri (LCJ), over Gunnarsfjorden (OGF) and over Kobbkrokvatnet (OKV), for freshwater diatoms. Diatom assemblages showed an increase in the planktonic diatoms relative to benthic diatoms, with an onset towards higher abundances of small centric planktonic diatoms at OGF (between c. 5270 and 5350 cal. yr BP) and OKV (between c. 5280 and 5350 cal. yr BP). Additionally, a diatom compositional shift was detected at LCJ between c. 5180 and 5300 cal. yr BP. Trend analysis found the main diatom compositional change at all three sites to occur at 5300 cal. yr BP. However, this synchronous diatom shift during the mid-Holocene varies in magnitude within the three Finnmark lakes. The abrupt planktonic:benthic diatom ratio changes are independent of the Pinus:Betula ratios and are likely to be a result of lake ice-cover changes, allowing longer growing seasons, greater water column stability and higher nutrient concentrations from surrounding catchments. This study highlights the significant differences in aquatic ecosystem and terrestrial vegetation response to climatic changes, with diatom assemblages at these sites either responding before the regional tree-line shift or to a separate climatic event within the mid-Holocene
Analysis of drainage system in Georgetown, Guyana
No full textIn 2015 Georgetown, Guyana suffered from major flooding due to heavy rainfall. The use of a centuries-old agricultural drainage system for the urban drainage of the largest urbanized area of Guyana, poses problems considering flood safety. In 2016 a report was published by a ‘Dutch Risk Reduction Team’ (DRR Team) with recommendations on how to reduce the current flood vulnerability. Based on the recommendations from this DRR report. A team of seven students from the Delft University of Technology, the Netherlands, went to Georgetown and analysed the drainage system in more detail. Several methods were developed in collaboration with local students and experts which can be used to analyse the system. This was done to increase the local capability of knowledge-based decision making on drainage issues in Guyana. This student’s induced project comprises three elements of the urban drainage system: the primary drainage channels, the local (secondary and tertiary) drainage canals, and the outlet structures. The work focussed primarily on the catchment area named South-Ruimveldt.Civil Engineering and GeosciencesHydraulic Engineering / Structural EngineeringMaster project repor
Subclinical changes in the juvenile crystalline macular dystrophy in Sjogren-Larsson syndrome detected by optical coherence tomography.
No full textContains fulltext :
70912.pdf (Publisher’s version ) (Open Access)PURPOSE: To study morphologic changes in the macula by optical coherence tomography (OCT) in patients with a crystalline macular dystrophy due to the autosomal recessive neurocutaneous Sjogren-Larsson syndrome (SLS). DESIGN: Retrospective observational case series. PARTICIPANTS: Twenty-seven eyes of 14 patients, mean age 14.6 (range, 3-24) years, with biochemically and genetically proven SLS underwent clinical and OCT investigation between September 2004 and September 2006. METHODS: All patients underwent full ophthalmologic examination including slit-lamp biomicroscopy and binocular ophthalmoscopy. Optical coherence tomography of all eyes was performed using the macular thickness map protocol of Stratus OCT. MAIN OUTCOME MEASURES: Macular morphology in clinical examination and OCT. RESULTS: Beside clinically visible perimacular crystalline deposits in all eyes of all study participants, macular morphology and reflectivity were significantly changed on OCT compared with healthy eyes. We found focal hyperreflectivities in all study eyes within the perifoveal ganglion cell layer and the inner plexiform layer, corresponding to the clinical localization of retinal crystals. More interestingly, a cystoid foveal degeneration on OCT was present in the majority of patients with SLS (18/27 eyes, or 67% of all eyes studied), varying from multiple microcystoid spaces to cystoid foveal atrophy. In general, patients who were severely affected on OCT showed intense changes on previously performed cerebral magnetic resonance spectroscopy. CONCLUSIONS: Patients with SLS show a childhood-onset crystalline macular dystrophy with cystoid foveal atrophy on OCT in most cases. The intraretinal deposition of lipid metabolites may lead to Muller cell degeneration with subsequent formation of cystoid spaces or atrophic changes within the fovea. Because this macular dystrophy is present in all examined patients with SLS, familiarity with this maculopathy seems important for the diagnosis of this rare systemic disease
Preference modelling approaches based on cumulative functions using simulation with applications
Full text linkIn decision making problems under uncertainty, Mean Variance Model (MVM) consistent
with Expected Utility Theory (EUT) plays an important role in ranking preferences for
various alternative options. Despite its wide use, this model is appropriate only when
random variables representing the alternative options are normally distributed and the utility
function to be maximized is quadratic; both are undesirable properties to be satisfied with
actual applications.
In this research, a novel methodology has been adopted in developing generalized models
that can reduce the deficiency of the existing models to solve large-scale decision problems,
along with applications to real-world disputes. More specifically, for eliciting preferences for
pairs of alternative options, two approaches are developed: one is based on Mean Variance
Model (MVM), which is consistent with Expected Utility Theory (EUT), and the second is
based on Analytic Hierarchy Processes (AHP). The main innovation in the first approach is
in reformulating MVM to be based on cumulative functions using simulation. Two models
under this approach are introduced: the first deals with ranking preferences for pairs of lotteries/options with non-negative outcomes only while the second, which is for risk
modelling, is a risk-preference model that concerns normalized lotteries representing risk
factors each is obtained from a multiplication decomposition of a lottery into its mean
multiplied by a risk factor. Both approximation models, which are preference-based using
the determined values for expected utility, have the potential to accommodate various
distribution functions with different utility functions and capable of handling decision
problems especially those encountered in financial economics. The study then reformulates
the second approach, AHP; a new algorithm, using simulation, introduces an approximation
method that restricts the level of inherent uncertainty to a certain limit. The research further focuses on proposing an integrated preference-based AHP model
introducing a novel approximation stepwise algorithm that combines the two modified
approaches, namely MVM and AHP; it multiplies the determined value for expected utility,
which results from implementing the modified MVM, by the one obtained from processing
AHP to obtain an aggregated weight indicator. The new integrated weight scale represents
an accurate and flexible tool that can be employed efficiently to solve decision making
problems for possible scenarios that concern financial economics Finally, to illustrate how the integrated model can be used as a practical methodology to
solve real life selection problems, this research explores the first empirical case study on
Tender Selection Process (TSP) in Kurdistan Region (KR) of Iraq; it is considered as an
inductive and a comprehensive investigation on TSP, which has received minimum
consideration in the region, and regarded as a significant contribution to this research. The
implementation of the proposed model to this case study shows that, for the evaluation of
construction tenders, the integrated approach is an appropriate model, which can be easily
modified to assume specific conditions of the proposed project. Using simulation, generated
data allows creation of a feedback system that can be utilized for the evaluation of future
projects in addition to its capability to make data handling easier and the evaluation process
less complex and time consuming
The influence of process variables on bioaerosol emission flux and exposure - estimating fugitive bioaerosol releases from static compost windrows
Full text linkAn assessment of the fugitive release of bioaerosols from static compost piles
was conducted at a green waste composting facility in South East England; this
representing the initial stage of a programme of research into the influence of
process parameters on bioaerosol emission flux. Wind tunnel experiments
conducted on the surface of static windrows generated specific bioaerosol
emission rates (SBER2s) at ground level of between 13 - 22 x10(3) cfu/m(2)/s for
mesophilic actinomycetes and between 8 - 11 x10(3) cfu/m(2)/s for Aspergillus
fumigatus. Air dispersion modelling of these emissions using the SCREEN3 air
dispersion model in area source term mode was used to generate source depletion
curves downwind of the facility for comparative purposes
Estimating fugitive bioaerosol releases from static compost windrows: feasibility of portable wind tunnel approach
Full text linkAn assessment of the fugitive release of bioaerosols from static compost piles
was conducted at a green waste composting facility in South East England; this
representing the initial stage of a programme of research into the influence of
process parameters on bioaerosol emission flux. Wind tunnel experiments
conducted on the surface of static windrows generated specific bioaerosol
emission rates (SBER2s) at ground level of between 13 - 22 x10 3 cfu/m 2 /s for
mesophilic actinomycetes and between 8 - 11 x10 3 cfu/m 2 /s for Aspergillus
fumigatus. Air dispersion modelling of these emissions using the SCREEN3 air
dispersion model in area source term mode was used to generate source depletion
curves downwind of the facility for comparative purposes
yap1b, a divergent Yap/Taz family member, cooperates with yap1 in survival and morphogenesis via common transcriptional targets
No full text© The Author(s).Yap1/Taz are well-known Hippo effectors triggering complex transcriptional programs controlling growth, survival and cancer progression. Here, we describe yap1b, a new Yap1/Taz family member with a unique transcriptional activation domain that cannot be phosphorylated by Src/Yes kinases. We show that yap1b evolved specifically in euteleosts (i.e. including medaka but not zebrafish) by duplication and adaptation of yap1. Using DamID-seq, we generated maps of chromatin occupancy for Yap1, Taz (Wwtr1) and Yap1b in gastrulating zebrafish and medaka embryos. Our comparative analyses uncover the genetic programs controlled by Yap family proteins during early embryogenesis, and show largely overlapping targets for Yap1 and Yap1b. CRISPR/Cas9-induced mutation of yap1b in medaka does not result in an overt phenotype during embryogenesis or adulthood. However, yap1b mutation strongly enhances the embryonic malformations observed in yap1 mutants. Thus yap1−/−; yap1b−/− double mutants display more severe body flattening, eye misshaping and increased apoptosis than yap1−/− single mutants, thus revealing overlapping gene functions. Our results indicate that, despite its divergent transactivation domain, Yap1b cooperates with Yap1 to regulate cell survival and tissue morphogenesis during early development.This work was supported by grants from the Ministerio de Economía, Industria y Competitividad de Espanña (BFU2014-53765-P, BFU2016- 81887-REDT, BFU2017-86339-P and MDM-2016-0687 to J.R.M.-M.)
Extreme Value Index Estimators and Smoothing Alternatives: A Critical Review
Full text linkExtreme-value theory and corresponding analysis is an issue extensively applied in many different fields. The central point of this theory is the estimation of a parameter γ, known as the extreme-value index. In this paper we review several extreme-value index estimators, ranging from the oldest ones to the most recent developments. Moreover, some smoothing and robustifying procedures of these estimators are presented.Extreme value index, Semi-parametric estimation, Smoothing modification
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