48 research outputs found
Sexuality and nationality: homophobic discourse and the 'national threat' in contemporary Latvia
No full textThis paper considers why attitudes towards gays and lesbians in
Latvia appear to be more intolerant than in all other EU member states. The paper
argues that while the legacy of communist discourses on homosexuality and
the impact of post-communist transition have played a role in shaping attitudes
towards sexuality and sexual minorities in Central and Eastern Europe, these
factors cannot sufficiently explain the divergence among post-communist states
and, in particular, do not account for Latvia’s extreme position. While acknowledging
that intolerance towards non-heteronormative sexualities cannot be explained
by a single factor, the paper argues that homosexuality has become particularly
reviled in Latvia because it has been widely discursively constructed as
a threat to the continued existence of the nation
Removal of plant pathogenic bacteria during agricultural managed aquifer recharge to produce irrigation water and protect plant health
No full textFresh water is an essential resource for life. Yet, overexploitation of water resources, rainfall shortages, and a decrease in water quality by pollution increase water scarcity worldwide. Since agricultural production consumes about 70% of the available fresh water resources, it is particularly vulnerable for water scarcity. Therefore, this research investigated agricultural aquifer storage, transfer and recovery (ASTR) as nature-based solution to store fresh water in the subsurface from where it can be reused for irrigation. The source water used for infiltration may carry plant pathogens that have to be removed during the storage. Otherwise, the recovered water poses a threat to crop production if pathogens are still present in the irrigation water. Consequently, an understanding of pathogen die-off and removal under relevant conditions found in aquifers is required to predict changes in water quality and protect plant health. In my research, I focussed on the removal of three plant pathogenic bacteria during ASTR: Ralstonia solanacearum and the Soft Rot Pectobacteriaceae, Dickeya solani and Pectobacterium carotovorum. They affect a broad variety of crops with hosts ranging from potato to flower bulbs, both being important cash crops worldwide and particularly in the Netherlands.An ASTR pilot site located in North Holland was investigated where tile drainage water (TDW) is collected from a 10 ha agricultural field and infiltrated into a sandy, anoxic, and originally brackish aquifer. The TDW can mix with surface water where the selected pathogens are regularly detected. ASTR uses separated wells for infiltration and abstraction of the recharged water. This creates a soil passage and forces the water to flow through the porous medium (sand layers) of the aquifer. Water microcosms and column experiments were used to simulate the aquifer processes in the laboratory and analysed pathogen removal during ASTR. The results showed that the die-off in the water phase depends on the residence time and ranged between 1.3 to 2.7 log10 after 10 or 60 days for R. solanacearum, respectively. A subpopulation of the bacteria persisted for a prolonged time at low concentrations which may pose a risk if the water is recovered too early. However, the soil passage within the aquifer proved to be highly effective in removing the bacteria by attachment (18 log10 after 1 m). Together with results of dose-response experiments where I studied the effect of contaminated irrigation water on potato plants, all results were ultimately combined in a quantitative microbial risk assessment (QMRA). QMRA is a useful (water) management tool to evaluate the treatment steps of water reclamation technologies and support decision-making processes. As a result of this PhD work, ASTR can be considered a natural treatment system to remove bacterial plant pathogens and provide safe irrigation water
Mapping of barley (Hordeum vulgare L.) beta-amylase alleles in which an amino acid substitution determines beta-amylase isoenzyme type and the level of free beta-amylase
No full textThe three beta -amylase genes (Bmy1, 2 and 3) in cultivated barley were mapped to chromosomes 4HL, 2HL And 4HL respectively using RFLP analysis. No recombinants between Bmy1 andBmy3 were detected among 264 DH lines. Polymorphism of the Sd1 and Sd2 isoenzymes of beta -amylase co-segregated with the Bmy loci on chromosome 4HL in a doubled-haploid population of the cross Chebec (Sd2)×Harrington (Sd1). This locus also explained 90·5% of the variation in the level of free enzyme between the two parents. Two cDNAs ofbeta -amylase were isolated by RT-PCR from the developing grains of Harrington (Sd1) and Galleon (Sd2). Alignment of the deduced amino acid sequences identified three amino-acid substitutions between the Sd2 and Sd1 forms of beta -amylase (Arg115 – Cys, Asp165 – Glu, and Val430 – Ala). Three allele-specific PCR primer pairs based on the three amino acid substitutions were used to amplify the beta -amylase genes in genomic DNA of sixteen barley cultivars/lines. Only the Arg115(Sd2)/Cys(Sd1) substitution was consistent with the isoenzyme form. This amino acid replacement reduced the pI of the Sd1 beta -amylase consistent with the fact that the Sd2 form is more basic than the Sd1 form when separated by IEF. The mutation from Arg115 to Cys in the Sd1 form also provides one more -SH group to form S-S-bridges. As bound beta -amylase is linked to the insoluble proteins of the endosperm and its inhibitor via disulphide bridges this could explain the higher level of binding exhibited by Sd1 vs Sd2. Thus a single amino acid substitution determines both the isoenzyme type and beta -amylase binding.Li, C.-D. ; Langridge, P. ; Zhang, X.-Q. ; Eckstein, P.E. ; Rossnagel, B.G. ; Lance, R.C.M. ; Lefol, E.B. ; Lu, M.-Y. ; Harvey, B.L. ; Scoles, G.J
AiRO: Direct Reverse Osmosis On Surface Water
No full textSurface water is microbiological unsafe, contains too much salts and is polluted with anthropogenic substances like pesticides, medicines, endocrine disruptors and industrial chemicals. The production of safe drinking water out of this water is only possible by applying a robust treatment. A process that can remove virtually all unwanted substances from the water in one step is reverse osmosis (RO). The main bottleneck in the wider application of RO with spiral wound membranes is the membrane fouling. This occurs on the feed spacer of the spiral wound membranes and at the membrane surface. This fouling occurs with particles, salts and/or microorganisms and results in a raise in pressure drop and reduction in permeate quality. An innovative idea to deal with above mentioned drawbacks is a membrane process in which spiral wounded NF/RO membrane elements are cleaned hydraulic (mechanically). The membrane is placed vertical and the membrane fouling is controlled by means of a periodic air/water flush, AiRO called (combination of the words air and RO). This AiRO process line needs hardly any pretreatment, is free of antiscalant dosage, uses less chemicals than traditional NF/RO and the concentrate is easy to dispose to surface water. The semi practical AiRO research described in this thesis is carried out with an automated pilot plant that was equipped with 2 8” RO membranes. The pilot was placed at the banks of the Hollandse IJssel river in Montfoort. The pre treatment was a drum filter. The pilot was started up in December 2010 and operated non stop for one and a half year. The research has shown that AiRO is a reliable robust barrier in a surface water purification process line. There is no effect on the operation of the process if the turbidity of the feed water varies between 4 and 75 FTU and if the oxygen content in the feed water varies (indication for microbiology). The process appeared to be economic interesting and withstood the practical durability test. Pre treatment of the feed water of the AiRO with a 120 µm micro strainer is sufficient. The commonly in Netherland applied 35 µm micro strainer is advised because it will give advantages for the AiRO process (less wear in pumps and energy recovery) and will promote the surge for a solution for the concentrate. Commercial available NF/RO elements are applicable in AiRO and the membrane stack is composed with pressure vessels with 2 8” elements in series. The investment costs of a complete drinking water treatment with the AiRO process are 20 to 33% lower than a treatment based on UF and RO. The application of 16” pressure vessels containing 2 16” elements in series may result in even lower investment costs. A flush was executed with the maximum allowed feed pressure (specs. Membrane manufacturer), the flush water velocity was 0,2 m/s in the membrane feed spacer, and with an air velocity of 0.24 Nm/s. Energy recovery from concentrate (Fedco) is essential to obtain energy efficiency. The flush program that resulted in a stable operation of the process consists of the steps. The flush interval is 4 hours and pressure drop NPD is the parameter for fine tuning of the interval duration. A flush should start if the NPD doesn’t rise linear anymore. A CIP has to take place, if the NPD before a flush rises above 50 kPa. The applied chemicals have to be balanced on the feed water composition. Manganese oxides by example are hardly washed out by a flush, they have to be removed during a CIP with citric or ascorbic acid. The design recovery is 35% and operation of AiRO at this low recovery results in a large concentrate stream, which is free of antiscalant and with a low content of salts. This flow is expected to be allowed to discharge to surface water. The flush water can be discharged to surface water, after sedimentation of the solids in it. The produced sludge is free of chemical additions. This will improve the useful application of the sludge. The used CIP fluid has to be discharged to the sewer after neutralisation of the pH.Sanitary EngineeringWater ManagementCivil Engineering and Geoscience
Key-factors for successful Product Generation Process implementation: A contract manufacturer perspective
No full textVDL-ETG is a contract-manufacturing firm active in among others the high-tech mechatronics market. Due to developments at VDL-ETG and the market in which they are active, VDL-ETG decided that they needed a more structured product development process. Therefore VDL-ETG has designed a tailor-made product development process which they call the Product Generation Process (PGP). This thesis focusses on the best practices for implementing such a process, the research was done in collaboration with VDL-ETG. There are numerous views on what such a product development process should look like and which ones are most successful. Less attention is given to the fact that to a large part the success of a product development process is dependent on the correct implementation of a process that fits the specific company. As such this research focusses on the aspects which are important for the successful implementation of a product development process and specifically PGP at VDL-ETG. The approach taken to reach this goal consists of three parts on which this research focusses: 1. The first source of information is scarce literature that has been written on practical experience with the implementation of a product development process and which challenges were encountered. 2. Secondly literature on change processes is considered since implementing a product development process means bringing more structure for employees. This can be approached as a type of a change process and literature on this subject can be valuable in improving the success of implementation. 3. Thirdly interviews with employees of VDL-ETG have been conducted as to contribute a practice oriented view to the research. Also information gathered from the interviews can be used to tailor the recommendations to VDL-ETG. As a result of this research a list was compiled the of most important aspects to look into when considering to implement a product development process, the aspects are separated into three categories. The first category is about the planning phase before implementing the process, the second phase is about aspects important when introducing a product development process and the last phase is about what is important during the use of the process when pursuing successful implementation. Preparation 1) Motivation and agreement on the need for a product development process and what it should look like 2) Stakeholder identification; who are involved and what are their responsibilities 3) Commitment and involvement from the senior-management throughout the process 4) Commit resources to the development and introduction of the new product development process 5) Make use of the experience from other companies about what the process should look like but make sure to adapt to the specific needs of the company Introduction 6) A clear and properly communicated vision where everyone knows his or her role 7) Initiators are needed for using the process to get the newly introduced process going. Thus buy-in from key-employees 8) Make use of multi-disciplinary teams and promote concurrent activities 9) Provide as much help as possible while introducing the process 10) Deal with complications during implementation concurrently, before they become complex 11) Be aware that it is a change process; the process needs to be sold to the employees 12) Manage expectations; it takes time to see the positive effects of a product development process 13) Be aware that the structure of a product development process can be intimidating for companies used to a flexible way of working During use 14) Be flexible with the design of the process, experience in the organization can help improve the process 15) Eventually make sure that improvements are applied continuously and that the process keeps evolving according to the needs of the company For VDL-ETG specifically it was concluded that this list is too extensive and does not fit with the company. The list of aspects and the literature on the subject in general is largely focussed towards the centralization of organizations. This is not how VDL-ETG works and it is not something that they strive for, they are more of a market-oriented and externally focussed organization, therefore a sub-selection has been made of the most important aspects for VDL-ETG and to what extent they should be applied. For VDL-ETG aspects 2, 3, 4, 6, 7, 11, 13 and 15 were found to be most important. The most important points of attention for VDL-ETG are as follows. - On the subject of everyone within the company knowing their role and responsibility it was concluded that although it is important, specifically naming everyone’s roles and responsibilities is not attainable, the good enough alternative would be to at least divide the tasks to the different departments. - Active involvement by the management, communicating that they find using the process important and show genuine interest in PGP, among others by planning regular meetings to discuss PGP progress of projects. - Alignment on what actually is the vision for which VDL-ETG is implementing PGP in order to prevent confusion. - Find the right people to start using the process and iron out the large hurdles of using PGP. - Keep an eye on the future as not to lose track on successful use of PGP once properly implemented.Engineering & Policy AnalysisSystems EngineeringTechnology, Policy and Managemen
Increasing the safety of use of medical devices by improving procurements
No full textThe summary can be found in the report.Engineering and Policy AnalysisPolicy Analysis, Safety Science GroupTechnology, Policy and Managemen
Inventarisatie en systeemopzet voor de automatisering van de modelspoorbaan te Madurodam
No full textIn Madurodam ligt een modelspoorbaan (schaal 1:25) die eigendom is van de N.V. Nederlandse Spoorwegen. In verband met de economische veroudering van de installatie heeft de NS besloten deze te vernieuwen. Omdat ook de wens aanwezig was de nu nog met de hand geregelde treinenloop te automatiseren is de NS een samenwerkingsverband aangegaan met de vakgroep Automatische Verkeerssystemen. In de eerste fase van het project is een inventarisatie van het huidige systeem gemaakt. Met behulp van deze gegevens is een projectopzet gemaakt voor de volgende fasen. Omdat de modelbaan tijdens het project in bedrijf moet blijven is een simulator ontwikkeld. Er is tevens een eerste aanzet gegeven voor het uiteindelijke besturingssysteem. De benodigde programmatuur, voor zowel de simulator als besturingssysteem, is geschreven in de taal Pascal. In eerste instantie wordt het simuleren en besturen uitgevoerd met behulp van een FLEX 6800 systeem.Electrical Engineering, Mathematics and Computer ScienceAutomatische Verkeerssysteme
Typing Mlo alleles for powdery mildew resistance in barley by single nucleotide polymorphism analysis using MALDI-ToF mass spectrometry
No full textSingle nucleotide polymorphisms (SNPs) have been identified in a range of plant genomes. Development of rapid, low-cost methods to enable their validation and implementation as molecular markers is now required for practical applications. We report the development of single and multi-nucleotide primer extension assays to genotype co-dominant SNPs from small quantities of barley leaf tissue. In the single nucleotide primer extension assay, a genotyping primer with its 3′ end directly flanking a SNP was annealed to a target sequence and extended by a single dideoxynucleotide triphosphate complementary to the polymorphic base. In the multi-nucleotide primer extension assay, designed to facilitate allele calling, the genotyping primer with its 3′ end flanking the SNP was extended by either 1 or 2 nucleotides, depending on the allele encountered. Extension products were analysed using MALDI-ToF mass spectrometry and, making use of the molecular weight difference between DNA bases, the incorporated nucleotides were identified by the increase in mass of the extended primers. Based on a SNP identified in the barley Mlo gene, primer extension assays were designed and used for co-dominant marker-assisted selection of barley seedlings segregating for mlo-mediated resistance to powdery mildew. This allowed accurate selection of progeny lines carrying alleles for resistance to powdery mildew, including heterozygotes. Doubled haploid barley progenies were screened for Mlo alleles and a complete correlation between mlo/mlo genotype and resistant phenotype was found The method has been used by barley breeders for routine selection of barley genotypes resistant to powdery mildew
Resistance in cultivated barleys to Pyrenophora teres f. teres and prospects of its utilisation in marker identification and breeding
No full textNet type net blotch (NTNB) is a prevalent disease in Australia, causing significant losses in barley yield and quality. Its impact can be reduced with the identification and utilisation of effective sources of resistance. Sixty-nine cultivated barley lines were screened as seedlings against 9 isolates of Pyrenophora teres f. teres from Australia, and in the field in Western Australia. Resistance expressed in seedlings was frequently expressed in adult plants in the field, indicating that these sources are potentially useful for resistance breeding. Of these lines, 24 with the best overall resistance were identified, which could be used against virulence diversity present in P. teres f. teres in Australia.
As a prelude to the evaluation of established mapping populations in the Australian Barley Molecular Marker Program, 42 parental lines were screened against a range of Australian isolates of P. teres f. teres. Variation in net blotch responses was observed among parents of the mapping populations. Ten principal mapping populations appear to provide opportunities to map resistances and identify molecular markers linked to NTNB resistance genes effective against Australian pathotypes
