Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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    Breeding progress and preparedness for mass-scale deployment of perennial lignocellulosic biomass crops switchgrass, miscanthus, willow and poplar
    Clifton-Brown, John ; Harfouche, Antoine ; Casler, Michael D. ; Dylan Jones, Huw ; Macalpine, William J. ; Murphy-Bokern, Donal ; Smart, Lawrence B. ; Adler, Anneli ; Ashman, Chris ; Awty-Carroll, Danny ; Bastien, Catherine ; Bopper, Sebastian ; Botnari, Vasile ; Brancourt-Hulmel, Maryse ; Chen, Zhiyong ; Clark, Lindsay V. ; Cosentino, Salvatore ; Dalton, Sue ; Davey, Chris ; Dolstra, Oene ; Donnison, Iain ; Flavell, Richard ; Greef, Joerg ; Hanley, Steve ; Hastings, Astley ; Hertzberg, Magnus ; Hsu, Tsai Wen ; Huang, Lin S. ; Iurato, Antonella ; Jensen, Elaine ; Jin, Xiaoli ; Jørgensen, Uffe ; Kiesel, Andreas ; Kim, Do Soon ; Liu, Jianxiu ; McCalmont, Jon P. ; McMahon, Bernard G. ; Mos, Michal ; Robson, Paul ; Sacks, Erik J. ; Sandu, Anatolii ; Scalici, Giovanni ; Schwarz, Kai ; Scordia, Danilo ; Shafiei, Reza ; Shield, Ian ; Slavov, Gancho ; Stanton, Brian J. ; Swaminathan, Kankshita ; Trindade, Luisa M. - \ 2019
    Global change biology Bioenergy 11 (2019)1. - ISSN 1757-1693 - p. 118 - 151.
    bioenergy - feedstocks - lignocellulose - M. sacchariflorus - M. sinensis - Miscanthus - Panicum virgatum - perennial biomass crop - Populus spp. - Salix spp.

    Genetic improvement through breeding is one of the key approaches to increasing biomass supply. This paper documents the breeding progress to date for four perennial biomass crops (PBCs) that have high output–input energy ratios: namely Panicum virgatum (switchgrass), species of the genera Miscanthus (miscanthus), Salix (willow) and Populus (poplar). For each crop, we report on the size of germplasm collections, the efforts to date to phenotype and genotype, the diversity available for breeding and on the scale of breeding work as indicated by number of attempted crosses. We also report on the development of faster and more precise breeding using molecular breeding techniques. Poplar is the model tree for genetic studies and is furthest ahead in terms of biological knowledge and genetic resources. Linkage maps, transgenesis and genome editing methods are now being used in commercially focused poplar breeding. These are in development in switchgrass, miscanthus and willow generating large genetic and phenotypic data sets requiring concomitant efforts in informatics to create summaries that can be accessed and used by practical breeders. Cultivars of switchgrass and miscanthus can be seed-based synthetic populations, semihybrids or clones. Willow and poplar cultivars are commercially deployed as clones. At local and regional level, the most advanced cultivars in each crop are at technology readiness levels which could be scaled to planting rates of thousands of hectares per year in about 5 years with existing commercial developers. Investment in further development of better cultivars is subject to current market failure and the long breeding cycles. We conclude that sustained public investment in breeding plays a key role in delivering future mass-scale deployment of PBCs.

    Hazardous Chemicals in Plastics in Marine Environments : International Pellet Watch
    Yamashita, Rei ; Tanaka, Kosuke ; Yeo, Bee Geok ; Takada, Hideshige ; Franeker, Jan A. van; Dalton, Megan ; Dale, Eric - \ 2019
    In: Hazardous Chemicals Associated with Plastics in the Marine Environment Springer Verlag (Handbook of Environmental Chemistry ) - ISBN 9783319955667 - p. 163 - 183.
    Additives - Equilibrium - Open ocean - Pellets - Sorption

    Marine plastic debris, including microplastics <5Â mm, contain additives as well as hydrophobic chemicals sorbed from surrounding seawater. A volunteer-based global monitoring programme entitled International Pellet Watch (IPW) is utilizing the sorptive nature of plastics, more specifically of beached polyethylene (PE) pellets, in order to measure persistent organic pollutants (POPs) throughout the world. Spatial patterns of polychlorinated biphenyls (PCBs) and organochlorine pesticides have been revealed. Original data of IPW show large piece-to-piece variability in PCB concentrations in pellets collected at each location. This is explained by the combination of slow sorption/desorption and large variabilities of speed and route of floating plastics. The sporadically high concentrations of POPs, both sorbed chemicals and hydrophobic additives, are frequently observed in pellets and the other microplastics in open ocean and remote islands. This poses a chemical threat to marine ecosystems in remote areas.

    Aquaculture
    Bardocz, Tamas ; Jansen, H.M. ; Cai, Junning ; Aguilar-Manjarrez, Jose ; Barrento, Sara ; Hunter, Shane A. ; Poelman, M. - \ 2018
    In: Building Industries at Sea: 'Blue Growth' and the New Maritime Economy / Johnson, Kate, Dalton, Gordon, Masters, Ian, River Publishers (River Publishers Series in Renewable Energy ) - ISBN 9788793609266 - p. 11 - 38.
    Seabed Mining
    Rozemeijer, M.J.C. ; Burg, S.W.K. van den; Jak, R.G. ; Lallier, Laura E. ; Craenenbroeck, Karel van - \ 2018
    In: Building Industries at Sea: 'Blue Growth' and the New Maritime Economy / Johnson, Katie, Dalton, Gordon, Masters, Ian, River Publishers (River Publishers Series in Renewable Energy ) - ISBN 9788793609266 - p. 73 - 136.
    Regulation and Planning in the Mediterranean Sea
    Rockmann, C. ; Vega Fernández, Tomás ; Pipitone, Carlo - \ 2018
    In: Building Industries at Sea: 'Blue Growth' and the New Maritime Economy / Johnson, Kate, Dalton, Gordon, Masters, Ian, River Publishers (River Publishers Series in Renewable Energy ) - ISBN 9788793609266 - p. 365 - 402.
    Knowledge gaps and research priorities in the prevention and control of hepatitis E virus infection
    Poel, W.H.M. Van der; Dalton, H.R. ; Johne, R. ; Pavio, N. ; Bouwknegt, M. ; Wu, T. ; Cook, N. ; Meng, X.J. - \ 2018
    Transboundary and Emerging Diseases 65 (2018)S1. - ISSN 1865-1674 - p. 22 - 29.
    Hepatitis E virus - HEV research priorities - Zoonosis
    Hepatitis E virus (HEV), family Hepeviridae, is a main cause of epidemic hepatitis in developing countries and sporadic and cluster cases of hepatitis in industrialized countries. There are an increasing number of reported cases in humans especially in industrialized countries, and there is a high potential for transboundary spread of zoonotic genotypes of the virus through the transport of pigs, pig products and by-products. Bloodborne transmission of the virus has been reported with a significant medical concern. To better coordinate HEV research and design better control measures of HEV infections in animals, a group of HEV experts reviewed the current knowledge on the disease and considered the existing disease control tools. It was concluded that there is a lack of in-depth information about the spread of the virus from pigs to humans. The role of animals other than pigs in the zoonotic transmission of the virus to humans and the extent of foodborne transmission are poorly understood. Factors involved in development of clinical disease such as infectious dose, susceptibility and virulence of virus strains need to be studied more extensively. However, such studies are greatly hindered by the absence of a broadly applicable, efficient and sensitive in vitro cell culture system for HEV. Diagnostic tools for HEV are available but need to be further validated, harmonized and standardized. Commercially available HEV vaccines for the control of HEV infection in animal populations are needed as such vaccines can minimize the zoonotic risk for humans. Anti-HEV drugs for treatment of HEV-infected patients need to be studied more extensively. The detailed expert review can be downloaded from the project website at http://www.discontools.eu/.
    Modernizing Polish Agricultural economics teaching and research: An evaluation of academic cooperation
    Dalton, Graham ; Heijman, W.J.M. ; Majewski, Edward - \ 2017
    Acta Scientiarum Polonorum. Oeconomia 16 (2017)4. - ISSN 1644-0757 - p. 13 - 21.
    Tempus - MBA - Human Capital - AGRIMBA - Cost Benefits of Education
    Twenty-five years ago in response to the collapse of communism in Poland, an academic consortium was formed around two Polish Universities of Life Sciences (formerly Universities of Agriculture) for a Tempus project. The consortium has expanded from a project to revise curricula in agricultural economics within a market economy to much wider educational and research interests. The consortium’s main achievement has been in the organisation and accreditation of MBA programmes which has subsequently been augmented by a network for other educational and research programmes in a number of countries (AGRIMBA). This article explores the social net benefits of this example of investment in human capital relying on the concepts laid down by the Nobel Prize winners Theodore Schulz and Gary Becker.
    Business case for mussel aquaculture in offshore wind farms in the North Sea
    Burg, S.W.K. van den; Kamermans, P. ; Blanch, M. ; Pletsas, D. ; Poelman, M. ; Soma, K. ; Dalton, G. - \ 2017
    Marine Policy 85 (2017). - ISSN 0308-597X - p. 1 - 7.
    Aquaculture - Business case - Mussels - Offshore wind - Risk assessment

    The European Blue Growth strategy aims to expand the new maritime sectors of aquaculture, energy, biotechnology, coastal tourism and mineral mining. Growth of these sectors will increases pressure on the seas, particularly on those areas that are densely used by traditional sectors such as fisheries and transport. This has triggered interest in developing multiuse of space and multiuse platforms at sea. This paper assesses the feasibility of offshore mussel production project in wind farms by design and ex-ante evaluation of a mussel aquaculture system in the North Sea. A system for mussel cultivation in the Dutch Borssele offshore wind farm was designed, producing both mussel seed and consumption-sized mussels with semi-submerged longlines. Based on the economic model and the risk assessment, this paper concludes that mussel aquaculture is an appealing commercial model for increased returns in offshore wind farms. The economic models shows that the internal rate of return and net present value are positive and based on the sensitivity analysis, it can be concluded that these results are robust.

    Mobilizing investors for blue growth
    Burg, Sander W.K. van den; Stuiver, Marian ; Bolman, Bas C. ; Wijnen, Roland ; Selnes, Trond ; Dalton, Gordon - \ 2017
    Frontiers in Marine Science 3 (2017)JAN. - ISSN 2296-7745
    Aquaculture - Blue growth - EU policy - Investment theory - Investors - Offshore wind

    The European Union's Blue Growth Strategy is a long term strategy to support sustainable growth in the marine and maritime sectors, aiming to contribute to innovation and economic growth (European Commission, 2012). The EU sees the financial sector as a key partner to bring about transition to sustainable consumption and production. However, knowledge about investment behavior, experience with working with these investors, and ways to engage investors in the Blue Growth sectors is lacking. This paper examines this knowledge gap. It characterizes investors and identifies investor behavior, investors' motives, and conditions and criteria relevant for investors to invest in Blue Growth sectors. The presented results are derived from a literature study on investors and investment behavior, an electronic survey and in-depth interviews. Stereotypical images of private equity bankers or wealthy individuals do not do justice to the diversity of investors involved in the Blue Growth sectors. These sectors are still in development and various risks reduce the willingness to invest. Risk mitigation should be seen as a shared responsibility of entrepreneurs, investors and governments. Government support must go further than financial support for research and development or technological demonstration projects. Proven technologies get stuck in the Valley of Death as investors alone are not willing to take the risk associated with upscaling of promising technologies. Tied in a reciprocal relationship, governments need to attract private investors-their capital, knowledge, and networks-to further grow of the Blue Growth sectors while investors need stable, predictable, and effective government support schemes to mitigate their financial risks.

    The supramolecular organization of a peptide-based nanocarrier at high molecular detail
    Rad-Malekshahi, M. ; Visscher, K.M. ; Rodrigues, J.P.G.L.M. ; Vries, R.J. de; Hennink, W.E. ; Baldus, M. ; Bonvin, A.M.J.J. ; Mastrobattista, E. - \ 2015
    Journal of the American Chemical Society 137 (2015)24. - ISSN 0002-7863 - p. 7775 - 7784.
    solid-state nmr - protein secondary structure - chemical-shift index - force-field - polypeptide vesicles - drug-delivery - beta-sheet - dynamics - nanovesicles - spectroscopy
    Nanovesicles self-assembled from amphiphilic peptides are promising candidates for applications in drug delivery. However, complete high-resolution data on the local and supramolecular organization of such materials has been elusive thus far, which is a substantial obstacle to their rational design. In the absence of precise information, nanovesicles built of amphiphilic “lipid-like” peptides are generally assumed to resemble liposomes that are organized from bilayers of peptides with a tail-to-tail ordering. Using the nanocarrier formed by the amphiphilic self-assembling peptide 2 (SA2 peptide) as an example, we derive the local and global organization of a multimega-Dalton peptide-based nanocarrier at high molecular detail and at close-to physiological conditions. By integrating a multitude of experimental techniques (solid-state NMR, AFM, SLS, DLS, FT-IR, CD) with large- and multiscale MD simulations, we show that SA2 nanocarriers are built of interdigitated antiparallel ß-sheets, which bear little resemblance to phospholipid liposomes. Our atomic level study allows analyzing the vesicle surface structure and dynamics as well as the intermolecular forces between peptides, providing a number of potential leads to improve and tune the biophysical properties of the nanocarrier. The herein presented approach may be of general utility to investigate peptide-based nanomaterials at high-resolution and at physiological conditions.
    Metabolomics in melon: A new opportunity for aroma analysis
    Allwood, J.W. ; Cheung, W.W.L. ; Xu, Y. ; Mumm, R. ; Vos, C.H. de; Deborde, C. ; Biais, B. ; Maucourt, M. ; Berger, Y. ; Schaffer, A. ; Rolin, D. ; Moing, A. ; Hall, R.D. ; Goodacre, R. - \ 2014
    Phytochemistry 99 (2014). - ISSN 0031-9422 - p. 61 - 72.
    charentais cantaloupe melons - volatile organic-compounds - oxidase antisense gene - cucumis-melo - gas-chromatography - flavor compounds - cv makdimon - fruit - constituents - sulfur
    Cucumis melo fruit is highly valued for its sweet and refreshing flesh, however the flavour and value are also highly influenced by aroma as dictated by volatile organic compounds (VOCs). A simple and robust method of sampling VOCs on polydimethylsiloxane (PDMS) has been developed. Contrasting cultivars of C. melo subspecies melo were investigated at commercial maturity: three cultivars of var. Cantalupensis group Charentais (cv. Cézanne, Escrito, and Dalton) known to exhibit differences in ripening behaviour and shelf-life, as well as one cultivar of var. Cantalupensis group Ha’Ogan (cv. Noy Yisre’el) and one non-climacteric cultivar of var. Inodorus (cv. Tam Dew). The melon cultivar selection was based upon fruits exhibiting clear differences (cv. Noy Yisre’el and Tam Dew) and similarities (cv. Cézanne, Escrito, and Dalton) in flavour. In total, 58 VOCs were detected by thermal desorption (TD)-GC–MS which permitted the discrimination of each cultivar via Principal component analysis (PCA). PCA indicated a reduction in VOCs in the non-climacteric cv. Tam Dew compared to the four Cantalupensis cultivars. Within the group Charentais melons, the differences between the short, mid and long shelf-life cultivars were considerable. 1H NMR analysis led to the quantification of 12 core amino acids, their levels were 3–10-fold greater in the Charentais melons, although they were reduced in the highly fragrant cv. Cézanne, indicating their role as VOC precursors. This study along with comparisons to more traditional labour intensive solid phase micro-extraction (SPME) GC–MS VOC profiling data has indicated that the high-throughput PDMS method is of great potential for the assessment of melon aroma and quality.
    Project Methodology: Using Markets to promote the sustainable utilization of crop genetic resources
    Anderson, C.L. ; Lipper, L. ; Dalton, T.J. ; Smale, M. ; Hellin, J. ; Hodgkin, T. ; Almekinders, C.J.M. ; Audi, P. ; Bellon, M.R. ; Cavatassi, R. ; Diakite, L. ; Jones, R. ; Oliver, E. ; Keleman, A. ; Meijer, M. ; Osborn, T. ; Nagarajan, L. ; Paz, A. ; Rodriguez, M. ; Sidibe, A. ; Salazar, L. - \ 2009
    In: Seed trade in rural markets. Implications for crop diversity and agricultural development. / Lipper, L, Anderson, C.L., Dalton, T.J., London : Earthscan - ISBN 9781844077854 - p. 31 - 50.
    Potato Seed Supply and Diversity: Dynamics of Local Markets of Cochabamba Province, Bolivia –A Case Study
    Almekinders, C.J.M. ; Cavatassi, R. ; Terceros, R. ; Pereira romero, R. ; Salazar, L. - \ 2009
    In: Seed trade in rural markets. Implications for crop diversity and agricultural development. / Lipper, L., Anderson, C.L., Dalton, T.J., London : Earthscan - ISBN 9781844077854 - p. 75 - 94.
    Regional welfare disparities and regional economic growth in Vietnam
    Nguyen Huy Hoang, - \ 2009
    Wageningen University. Promotor(en): Wim Heijman, co-promotor(en): Johan van Ophem. - [S.l. : S.n. - ISBN 9789085853190 - 230
    rurale welzijnszorg - regionale ontwikkeling - economische groei - gezondheidszorg - volksgezondheid - onderwijs - inkomen - inkomensverdeling - regio's - platteland - vietnam - economische verandering - rural welfare - regional development - economic growth - health care - public health - education - income - income distribution - regions - rural areas - vietnam - economic change
    This study had multiple objectives. First, it aimed at examining regional inequality
    in several welfare variables, such as health and education during the 1998-2004 period, and
    per capita income over time from 1990 to 2006. The first objective of the study was to gain
    a better understanding about the magnitude and evolution of regional inequality in health,
    education and per capita income. In addition, the study paid attention to the levels and
    trends of between- and within-region differences in these welfare variables separately. The
    second objective of the study was to explore the relationship between regional income
    inequality and regional growth during the 1990-2006 period in order to provide knowledge
    about empirical evidence of the relation between regional income inequality and regional
    economic growth in Vietnam. The third and final objective of the study was to examine the
    regional growth patterns in the country for the growth episode stretching from 1990 to
    2006. Also in the third objective of the study, the role of space and spatial autocorrelations
    were considered in order to provide a better understanding about the spatial interaction
    between regions in Vietnam and its impact on regional economic growth. To attain these
    objectives, the study employed various methodological methods in order to measure and
    analyze regional inequality in welfare variables, to explore the empirical relationship
    between inequality and growth, and to test for growth patterns in the Vietnam economy.
    The study was subdivided into eight chapters. Besides the introduction provided in chapter
    one, an overview, conclusions, discussion and recommendations given in chapter eight, the
    other six chapters, from chapter two to chapter seven, covered all issues relating to
    characteristics of reform and welfare in Vietnam, the literature, methodological approach
    and empirical analysis.
    Economic reforms and changes in welfare in Vietnam were elaborated and
    discussed in chapter two. The main focus of this chapter was to discuss the macroeconomic
    situation, as well as the implementation of the economic reforms called doi moi,
    and its impact on people’s welfare. As discussed in the chapter, before the doi moi, the
    welfare system in Vietnam functioned quite well. Most Vietnamese people had equal access
    to most welfare services provided by the government, irrespective of religion, ethnicity or
    social status. Similar to other communist countries, welfare distribution in Vietnam before
    the doi moi was relatively equal, although the quality of the welfare system with respect to
    services offered was still questionable in terms of catching up to the international standard.
    At the time, most Vietnamese people enjoyed free access to the healthcare system. Pupils
    and students got free education at all levels. As a result, the free systems culminated in
    good health records attained throughout the country, high enrolment rates and a high rate of
    literacy among the Vietnamese people compared with other developing countries with the
    same or slightly higher level of development.
    The situation and condition of welfare, such as education and health after the doi
    moi, were also discussed and compared with the condition of welfare before doi moi to
    evaluate the impact of high and relatively high rates of economic growth of 6-9% per
    annum on a changing welfare system, by explanatorily analyzing the welfare system, using
    Gini coefficients. This showed that regional inequality in the country had generally
    changed.
    The methodological issue regarding measuring and analyzing regional welfare
    inequality was dealt with in chapter three. Apart from discussing the theoretical approach and empirical measurement models, the chapter also provided a short review of the
    literature on multidimensional regional inequality. From the various approaches to welfare
    inequality measurement and analysis, the present study chose the multidimensional
    approach, using Theil’s second index as the inequality measure. The rationale for using
    Theil’s second index (measure) and the valuable properties of the Theil’s second index
    were also discussed in this chapter. Theil’s second measure satisfies the property of
    additive decomposability and is very informative about the status of the distribution of
    well-being. Additive decomposability property meant that overall inequality could be
    decomposed into within- and between-region inequality, which would be very meaningful
    for understanding magnitudes and trends of regional inequality. Theil’s second measure
    also satisfied several desirable properties as measuring regional income/welfare inequality,
    such as mean independence, population-size independence, and the Pigou-Dalton principle
    of transfers. In order to compute Theil’s second measure of inequality, there is a need for
    estimating a composite index, based on the aggregate function by Maasoumi, in which the
    indicators’ coefficients and their associated weights are to be estimated. To do so, the
    chapter also developed the measurement models based on the principal component models
    (PCA) and partial common principal component models (PCPC), developed and used by
    Flury. These two types of models were discussed in detail in order to help the readers to
    comprehend the subsequent empirical parts of the thesis.
    The measurement and analysis of regional inequality for two welfare variables,
    namely health and education, were given in chapter four and chapter five, respectively.
    In chapter four, we proceeded with the measurement and analysis for health
    facilities and health status, and also examined spillover effects, for example, that health
    facilities in one region would affect people’s health status in the first-order adjacent
    province(s). We carried out several tests for spatial dependence among these two subcomponents
    of health. The results in chapter four revealed that total regional inequality had
    different patterns for healthcare facilities and health status during the 1998-2004 period.
    Generally, regional inequality in both the healthcare facilities and health status moderately
    decreased in Vietnam over the 1998-2004 period. However, there was a sign of increase
    during this stretch of time, as the results found in chapter four showed a slight increase in
    inequality in both components of health over the 1998-2002 period, and then it decreased in
    the next period.
    Empirical findings in chapter four also proved the importance of spillover effects
    prevailing in the case of the health component. Healthcare services seemed to be more
    equally distributed in the case of contiguity than in the case of non-contiguity, as Theil’s
    second measure in the former was lower than that in the latter. This finding indicated that if
    we ignored the existence of spillover effects, the regional inequality would be exaggerated.
    The tests for spatial dependence among health components were also conducted in
    chapter four for several specifications regarding the relationship between health status and
    health facilities. The results of the tests confirmed the existence of spatial effects between
    the two dimensions of health. The test also proved that the spatial error model was an
    appropriate specification for analysis of the relationship between the composite index with
    respect to health status and the composite index with respect to health facilities, while the
    spatial lagged model was a more appropriate specification to analyze the relationship
    between the composite index with respect to health status and the indicators of health
    facilities.
    Following chapter four, the measurement and analysis of multidimensional regional
    inequality for the education component were carried out in chapter five. However, different
    from chapter four, contiguity effects were not considered in this chapter, because we argued
    that due to mandatory education applied in Vietnam, pupils were not allowed to attend
    school in other regions (provinces) than they were registered to live (even though in
    practice pupils would seek education in other regions other than the one they lived, but this
    phenomenon was not common, so we did not have statistics for analysis). Thus, as a result,
    we did not take spatial dependence into consideration.
    For regional inequality in education facilities, the research showed that total
    inequality, its between-region term and within-region components all go into opposite
    directions between the two periods. However, the change in the within-region inequality
    was in contrast with the changes in total regional inequality. The between-region
    component as the total regional inequality and the between-region component in education
    facilities first decreased during the period 1998-2002 and then increased during the period
    2002-2004, while the within-region inequality increased during the 1998-2002 period, then
    decreased during the 2002-2004 period. As research findings revealed, the distribution of
    education facilities among the regions in Vietnam was a bit more unequal over time.
    Meanwhile, the change over time of the within-region component of inequality was very
    moderate.
    For regional inequality in enrolments, our findings showed that the pattern of total
    regional inequality and its decomposed terms were the same as all of them increased in the
    first period (1998-2002), and declined in the next period (2002-2004). The structural shares
    of between-region and within-region inequality in the total inequality told us that in all
    three years under study the between-region term made up a larger part in the total
    inequality. These implied that the differences in enrolments between regions were more
    significant to the total inequality than the differences in enrolments within regions.
    The comparative composite index with respect to education facilities and the
    composite index with respect to enrolments presented in chapter five revealed that there
    was a sharp contrast between the two dimensions of education, as the most-favored regions
    with respect to enrolments were those in the lowland areas with least and medium-favored
    education facilities. The least-favored regions with respect to the education enrolments
    were those in the upland areas, which were very high-favored with respect to education
    facilities in terms of the composite index.
    Chapter six presented the measurement and analysis of the regional income
    inequality, and explored the evolution of income disparities, its decomposed terms as well
    as its relationship with economic growth among regions in Vietnam in the period from
    1990 to 2006. The findings confirmed that generally the regional income inequality in the
    country moderately increased over time. The decomposition of the total inequality revealed
    that within-region inequality decreased, while between-region increased over time.
    However, the size of within-region income inequality differed among regions in the
    country, as within-region Theil’s second inequality measure showed different trends.
    The empirical exploration of the relationship between regional inequality and
    regional growth found revealed different patterns of the relationship. The estimates from
    the panel data regression have found a positive relationship between the rate of economic
    growth and the initial level of per capita income in all the cases studied. Meanwhile, using
    the pooled OLS technique, we found negative relationships between growth and inequality for all the cases studied: without both controls and regional dummies, with the controls and
    no regional dummies, and with both controls and regional dummies.
    The test for the validity of the method (either the fixed effects or random effects is
    more appropriate and preferred) revealed that the fixed effects method was appropriate and
    preferred for the cases: without both the controls and dummies and with controls but no
    dummies in the growth model, while the random effects technique was more appropriate
    and more preferred for the case with both the controls, regional and time dummies.
    Interestingly, estimates by both the fixed effects and random effects methods revealed that
    there was both a positive and negative relationship between regional growth rate and initial
    level of per capita income.
    The empirical results of the relationship between regional inequality and regional
    growth show that the estimated relationship between inequality and growth changes when
    using different estimation techniques. However, the estimation using panel data regression,
    the fixed effects and most cases of random effects methods seem to support the theoretical
    argument and empirical findings that there is a positive correlation between growth and
    inequality for developing economies like Vietnam’s, while pooled OLS regression yields
    the results of a negative relationship between the two variables: inequality and growth.
    Examination of the growth patterns or tests (absolute β-convergence test and ADF
    panel IPS t-bar test based on unit root test) for convergence in regional income was
    conducted in chapter seven. All the tests for convergence were rejected, which meant that
    regional income in Vietnam did not converge towards one another. Based on an informal
    exploratory data analysis we may conclude that divergence of regional income took place
    in Vietnam, given the size of beta and its high statistical significance.
    Parallel with the test for the per capita GDP convergence, the chapter did also
    attempt to test for the spatial dependence among provinces, in order to explain the growth
    pattern of one province in relation with that of others. However, the Moran’s I and both the
    LM statistics did not support our prior assumption of the spatial dependence among
    provinces in the growth progress.
    Lastly, chapter eight provided an overview, the conclusions, discussion and
    recommendations based on the entire research conducted in this study. The chapter drew
    several key conclusions. First, regarding the regional inequality in health and education, the
    key point was that the results from the multidimensional approach to measurement and
    analysis were satisfactory, because generally, welfare inequality in Vietnam, according to
    the World Bank reports, increased over time, as inequality in income per capita increased.
    However, the multidimensional approach found that inequality in education and health
    decreased over the period studied. Additionally, the chapter concluded that spillover effects
    were important in the case of measuring and analyzing regional inequality for health, and
    they should be taken into consideration. For education, analyzing the comparative
    composite indices with respect to education facilities and education enrolments revealed
    that in some regions these two indices did not coincide, which meant that regions, which
    were favored in terms of the composite index with respect to education facilities, were not
    the ones that were favored in terms of the composite index with respect to enrolments and
    vice versa. This conclusion would be very useful for policymakers in considering the
    effective way to invest in improving general education in the country.
    Chapter eight also described several limitations of the study, regarding the
    approaches used in the study, the number of indicators used, the sources and duration of the data. However, the limitations were not critical, but if we overcame these setbacks, the
    results of the study would be more impressive, empirically speaking. In addition, several
    recommendations for policy were given in chapter eight, regarding policy on health and
    education, and policy on regional development and sustainable development.
    Economic impact of prospective risk management instruments under alternative policy scenarios
    Asseldonk, M.A.P.M. van; Majewski, E. ; Meuwissen, M.P.M. ; Was, A. ; Guba, W. ; Dalton, G. ; Landmesser, J. ; Berg, E. van den; Huirne, R.B.M. - \ 2009
    In: Income stabilization in a changing agricultural world: policy and tools / Berg, Ernst, Huirne, Ruud, Majewski, Edward, Meuwissen, Miranda, Warszawa : Editorial House Wies Jutra, Limited - ISBN 9788389503657 - p. 218 - 227.
    Odor and irritation thresholds for ammonia: A comparison between static and dynamic olfactometry
    Smeets, M.A.M. ; Bulsing, P.J. ; Rooden, S. van; Steinmann, R. ; Ru, J.A. de; Ogink, N.W.M. ; Thriel, C. van; Dalton, P.H. - \ 2007
    Chemical Senses 32 (2007)1. - ISSN 0379-864X - p. 11 - 20.
    occupational-exposure limits - temporal integration - allergic rhinitis - sensitivity - chemicals - air - performance - irritants - workers - humans
    Odor and lateralization (irritation) thresholds (LTs) for ammonia vapor were measured using static and dynamic olfactometry. The purpose of the study was to explore the test-retest reliability and comparability of dynamic olfactometry methodology, generally used to determine odor thresholds following European Committee for Standardization guidelines in the context of odor regulations to outside emissions, with static olfactometry. Within a 2-week period, odor and LTs for ammonia were obtained twice for each method for 24 females. No significant differences between methods were found: mean odor detection thresholds (ODTs) were 2.6 parts per million (ppm) for either method (P = 0.96), and mean LTs were 31.7 and 60.9 ppm for the static and dynamic method, respectively (P = 0.07). Test-retest reliability was higher for the dynamic than for the static method (r = 0.61 vs. 0.14 for ODTs and r = 0.86 vs. 0.45 for LTs). The choice of optimal method for any application, however, depends not only on psychometric factors but also on practical factors such as physicochemical properties of the compound, availability of equipment and expertise, task efficiency, and costs.
    Setting occupational exposure limits in humans: contributions from the field of experimental psychology
    Smeets, M.A.M. ; Kroeze, J.H.A. ; Dalton, P.M. - \ 2006
    International Archives of Occupational and Environmental Health 79 (2006)4. - ISSN 0340-0131 - p. 299 - 307.
    irritation thresholds - temporal integration - nasal pungency - eye irritation - psychometric function - sensory irritation - spatial summation - perceived odor - sensitivity - chemicals
    Psychophysical methods from the field of experimental psychology are evaluated for their utility in the derivation of occupational exposure limits (OELs) for volatile chemicals based on acute sensory irritation in humans. The lateralization threshold method, which involves the localization of trigeminal vapor to the stimulated nostril, is evaluated for its underlying assumptions, reliability and validity. Whole body exposures, on the other hand, which involve the controlled, ambient exposure of human subjects to the irritant at one or a series of concentrations for an extended period are also discussed. It is concluded that the single-organ psychophysical method is largely resistant to response bias is practical and economical. However, its reliability and validity need further assessment. Whole body exposures, while having enhanced ecological validity, are more prone to demand characteristics, response bias, and subject beliefs than the traditional psychophysical procedures. An approach that involves the exposure of only the most sensitive organs such as the eyes and nose, via a mask or facebox, could facilitate the administration and alternation of odorant/irritant stimuli over a wide range of concentrations while enhancing ecological validity.
    Perceived odor and irritation of isopropanol: a comparison between naive controls and occupationally exposed workers
    Smeets, M.A.M. ; Dalton, P. - \ 2002
    International Archives of Occupational and Environmental Health 75 (2002)8. - ISSN 0340-0131 - p. 541 - 548.
    methyl isobutyl ketone - organic-solvents - health symptoms - mixtures - acetone - adaptation - thresholds - ethanol - humans
    Objectives. To assess sensory irritation levels from isopropanol (IPA) unconfounded by subjective evaluations of odor for comparison against the recommended exposure limits (400 ppm threshold limit value (TLV); American Conference of Governmental Industrial Hygienists). Method. The lateralization method was used to assess intra-nasal irritation thresholds for IPA, while odor detection thresholds were also measured. Thresholds for 1-butanol and phenyl ethyl alcohol (PEA) were obtained as positive and negative irritant controls. To compare potency and hedonic characteristics, subjects provided subjective ratings of odor, irritation and annoyance intensity for three concentrations of each chemical. Workers occupationally exposed to IPA (n=26) were compared with previously unexposed controls (n=26). Results. The (geometric) mean odor detection threshold for IPA was slightly higher among exposed workers than controls (39 ppm vs. 11 ppm). Lateralization thresholds measuring intra-nasal irritation were elevated when compared with controls (6,083 ppm in exposed workers vs. 3,361 ppm in naïve controls), with a significantly higher proportion of phlebotomists being unable to lateralize the maximum concentration regarded as safe, than controls. Calculations of the 6th percentile for lateralization thresholds revealed that 95% of the sample did not experience sensory irritation below 512 ppm. Thus, while odor detection thresholds were well below the current recommended exposure limits, the irritation thresholds were well above these values. The odor, irritation and annoyance from IPA was perceived, on average, as between weak and almost strong, from lowest to highest concentration. Conclusions. The results indicate that current exposure guidelines would be adequately protective of the acute adverse effect of nasal sensory irritation, as operationally defined by the intra-nasal lateralization threshold. Exposures to higher concentrations should perhaps be evaluated on the basis of existing knowledge about systemic, rather than local (e.g., irritation), toxic effects. IPA appears to be a weak sensory irritant and occupational exposure to IPA appears to elicit small changes in sensitivity that do not generalize to other odorants (e.g., PEA and 1-butanol) and are likely to be reversible
    Inhibition of septic shock in mice by an oligopeptide from the beta-chain of human chorionic gonadotrophin hormone
    Khan, N.A. ; Khan, A. ; Savelkoul, H.F.J. ; Benner, R. - \ 2002
    Human Immunology 63 (2002). - ISSN 0198-8859 - p. 1 - 7.
    Human chorionic gonadotrophin (hCG) is a heterodimeric placental glycoprotein hormone required in pregnancy. In human pregnancy urine and in commercial hCG preparations (c-hCG) it occurs in a variety of forms, including breakdown products. Several reports have suggested modulation of the immune system by intact hormone, but such effects of breakdown products have not been reported. In a related article (Hum Immunol 62:1315, 2001), it is reported that a 400–2000 Dalton (Da) fraction from c-hCG and from human pregnancy urine inhibits Th1-mediated diabetes in NOD mice. The active component(s) were called natural (immuno)modulatory pregnancy factor(s) (NMPF). This study reports that a single treatment with the same low molecular weight NMPF fraction up to 24-h after high dose lipopolysaccharide (LPS) injection inhibited septic shock in mice. This counteracting effect of NMPF paralleled the downregulation of the effects of LPS on the production of macrophage migration inhibitory factor (MIF) by spleen cells, on the plasma level of liver aminotransferase, and on the expression of several splenic lymphocyte and macrophage surface markers. Based on the primary structure of the -chain of hCG a synthetic hexapeptide Valine-Leucin-Proline-Alanine-Leucine-Proline (VLPALP) was designed, which demonstrated it to have the same protective effects as the 400–2000 Da NMPF fraction. These results indicate a new strategy for the treatment of septic shock and the potential of therapeutic use of this synthetic oligopeptide.
    Acute sensory irritation from exposure to isopropanol(2-propanol) at TLV in workers and controls : objective versus subjective effects
    Smeets, M.A.M. ; Maute, C. ; Dalton, P.H. - \ 2002
    Annals of Occupational Hygiene 46 (2002)4. - ISSN 0003-4878 - p. 359 - 373.
    Objectives. Phlebotomists occupationally exposed to isopropanol (IPA) (2-propanol) and naïve controls (n = 12 per group) were exposed to the time-weighted average threshold limit value of 400 p.p.m. IPA for 4 h in an environmental chamber to investigate: (i) acute effects of sensory irritation using subjective health symptom reports and objective, physiological end-points; and (ii) differences in measured effects in relation to exposure history. Methods. Before, during and after exposure subjects gave self-reports of health complaints. During exposure subjects rated the intensity of the odor, sensory irritation and annoyance. Objective end-points of ocular hyperemia, nasal congestion, nasal secretion and respiration were obtained at various times before, during and after exposure. Results were compared with exposure to phenylethyl alcohol (PEA), a negative control for irritation, and to clean air (CA), a negative control for odor and irritation, using a within-subjects design. Results. Significantly higher intensity ratings of odor, irritation and annoyance were reported during the exposure to IPA, when compared with exposure to CA or PEA. Nevertheless, the overall level of reported sensory irritation to IPA was low and perceived as ‘weak’ on average. Health symptom ratings were not significantly elevated for IPA as compared with PEA or CA exposure. The only physiological end-point that showed a change exclusively in the IPA condition was respiration frequency: relative to baseline, respiration frequency increased in response to IPA in both groups. No differences were encountered between the occupationally exposed and the control groups. Conclusions. The increase in respiration frequency in response to IPA may reflect either a reflexive change due to sensory irritation (an autonomic event) or a voluntary change in breathing in response to perception of an unpleasant, solvent-like odor (a physiological event caused by cognitive mediation). Our findings on objective end-points, including nasal and ocular sensory irritation, did not confirm subjective irritation reports. Irritation reports and odor intensity decreased, rather than increased, over time, lending credence to the cognitive argument and suggesting that the elevated subjective responses to IPA may be mediated by responses to its odor.
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