Staff Publications

Staff Publications

  • external user (warningwarning)
  • Log in as
  • language uk
  • About

    '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.

    We have a manual that explains all the features 

Current refinement(s):

Records 1 - 12 / 12

  • help
  • print

    Print search results

  • export

    Export search results

  • alert
    We will mail you new results for this query: keywords==progress
Check title to add to marked list
An international comparison of productivity change in the textile and clothing industry: a bootstrapped Malmquist index approach
Kapelko, M. ; Oude Lansink, A.G.J.M. - \ 2015
Empirical Economics 48 (2015)4. - ISSN 0377-7332 - p. 1499 - 1523.
nonparametric frontier models - data envelopment analysis - technical efficiency - industrialized countries - technological-change - profitability change - detecting outliers - framework - progress - growth
Firms in the textile and clothing industry operate in competitive international markets characterized by the liberalized trade after the removal of multi-fiber agreement quotas in 2005, and have to address rapid changes in consumer preferences and production technology. Hence, improving competitiveness is crucial for firm survival. Competitiveness of the sector often depends on its firms meeting their production potential. This paper analyzes productivity changes in the textile and clothing industry worldwide during the period 1995-2004. A bootstrapped Malmquist approach is used to identify the respective contributions of technical change, technical efficiency change, and scale efficiency change. Moreover, differences in productivity changes across different groups of firms are statistically assessed. Our results show a relatively small overall productivity increase for both textile and clothing firms due to positive technical change, despite declines in technical and scale efficiency. Furthermore, our results indicate that productivity and its components differ for textile firms and clothing firms, for firms in countries that benefited and did not benefit from the quotas' elimination, and for firms in different regions. © 2014 The Author(s).
Predicted accuracy of and response to genomic selection for new traits in dairy cattle
Calus, M.P.L. ; Haas, Y. de; Pszczola, M.J. ; Veerkamp, R.F. - \ 2013
Animal 7 (2013)2. - ISSN 1751-7311 - p. 183 - 191.
genetic-relationship information - breeding programs - holstein cattle - energy-balance - strategies - emissions - progress - schemes - designs - impact
Genomic selection relaxes the requirement of traditional selection tools to have phenotypic measurements on close relatives of all selection candidates. This opens up possibilities to select for traits that are difficult or expensive to measure. The objectives of this paper were to predict accuracy of and response to genomic selection for a new trait, considering that only a cow reference population of moderate size was available for the new trait, and that selection simultaneously targeted an index and this new trait. Accuracy for and response to selection were deterministically evaluated for three different breeding goals. Single trait selection for the new trait based only on a limited cow reference population of up to 10 000 cows, showed that maximum genetic responses of 0.20 and 0.28 genetic standard deviation (s.d.) per year can be achieved for traits with a heritability of 0.05 and 0.30, respectively. Adding information from the index based on a reference population of 5000 bulls, and assuming a genetic correlation of 0.5, increased genetic response for both heritability levels by up to 0.14 genetic s.d. per year. The scenario with simultaneous selection for the new trait and the index, yielded a substantially lower response for the new trait, especially when the genetic correlation with the index was negative. Despite the lower response for the index, whenever the new trait had considerable economic value, including the cow reference population considerably improved the genetic response for the new trait. For scenarios with a zero or negative genetic correlation with the index and equal economic value for the index and the new trait, a reference population of 2000 cows increased genetic response for the new trait with at least 0.10 and 0.20 genetic s.d. per year, for heritability levels of 0.05 and 0.30, respectively. We conclude that for new traits with a very small or positive genetic correlation with the index, and a high positive economic value, considerable genetic response can already be achieved based on a cow reference population with only 2000 records, even when the reliability of individual genomic breeding values is much lower than currently accepted in dairy cattle breeding programs. New traits may generally have a negative genetic correlation with the index and a small positive economic value. For such new traits, cow reference populations of at least 10 000 cows may be required to achieve acceptable levels of genetic response for the new trait and for the whole breeding goal.
Response to genomic selection: The Bulmer effect and the potential of genomic selection when the number of phenotypic records is limiting
Grevenhof, E.M. van; Arendonk, J.A.M. van; Bijma, P. - \ 2012
Genetics, Selection, Evolution 44 (2012)1. - ISSN 0999-193X
breeding programs - prediction - progress - traits
Background Over the last ten years, genomic selection has developed enormously. Simulations and results on real data suggest that breeding values can be predicted with high accuracy using genetic markers alone. However, to reach high accuracies, large reference populations are needed. In many livestock populations or even species, such populations cannot be established when traits are difficult or expensive to record, or when the population size is small. The value of genomic selection is then questionable. Methods In this study, we compare traditional breeding schemes based on own performance or progeny information to genomic selection schemes, for which the number of phenotypic records is limiting. Deterministic simulations were performed using selection index theory. Our focus was on the equilibrium response obtained after a few generations of selection. Therefore, we first investigated the magnitude of the Bulmer effect with genomic selection. Results Results showed that the reduction in response due to the Bulmer effect is the same for genomic selection as for selection based on traditional BLUP estimated breeding values, and is independent of the accuracy of selection. The reduction in response with genomic selection is greater than with selection based directly on phenotypes without the use of pedigree information, such as mass selection. To maximize the accuracy of genomic estimated breeding values when the number of phenotypic records is limiting, the same individuals should be phenotyped and genotyped, rather than genotyping parents and phenotyping their progeny. When the generation interval cannot be reduced with genomic selection, large reference populations are required to obtain a similar response to that with selection based on BLUP estimated breeding values based on own performance or progeny information. However, when a genomic selection scheme has a moderate decrease in generation interval, relatively small reference population sizes are needed to obtain a similar response to that with selection on traditional BLUP estimated breeding values. Conclusions When the trait of interest cannot be recorded on the selection candidate, genomic selection schemes are very attractive even when the number of phenotypic records is limited, because traditional breeding requires progeny testing schemes with long generation intervals in those cases.
Processing of Arsenopyritic Gold Concentrates by Partial Bio-Oxidation Followed by Bioreduction
Hol, A. ; Weijden, R.D. van der; Weert, G. van; Kondos, P. ; Buisman, C.J.N. - \ 2011
Environmental Science and Technology 45 (2011)15. - ISSN 0013-936X - p. 6316 - 6321.
sulfur - dissolution - bioreactor - mechanisms - reduction - oxidation - minerals - progress - removal - iron
Gold is commonly liberated from sulfide minerals by chemical and biological oxidation. Although these technologies are successful, they are costly and produce acidic waste streams. Removal of mineral-sulfur to overcome the mineralogical barrier could also be done by bioreduction, producing hydrogen sulfide (H2S). To make the sulfur within these minerals available for bioreduction, the use of partial bio-oxidation as a pretreatment to oxidize the sulfides to elemental sulfur was investigated in gas lift loop reactor experiments. Experiments at 35 °C using a refractory concentrate showed that at pH 2 arsenopyrite is preferentially partially oxidized over pyrite and that elemental sulfur can be subsequently converted into H2S at pH 5 via bioreduction using H2 gas. A single partial bio-oxidation/bioreduction treatment increased the gold recovery of the concentrate from 6% to 39%. As elemental sulfur seems to inhibit further oxidation by covering the mineral surface, several treatments may be required to reach a gold recovery >90%. Depending on the number of treatments this method could be an interesting alternative to bio-oxidation
Effects of genomic selection on genetic improvement, inbreeding, and merit of young versus proven bulls
Roos, A.P.W. de; Schrooten, C. ; Veerkamp, R.F. ; Arendonk, J.A.M. van - \ 2011
Journal of Dairy Science 94 (2011)3. - ISSN 0022-0302 - p. 1559 - 1567.
marker-assisted selection - cattle breeding schemes - dairy-cattle - wide selection - populations - prediction - progress - gain
Genomic selection has the potential to revolutionize dairy cattle breeding because young animals can be accurately selected as parents, leading to a much shorter generation interval and higher rates of genetic gain. The aims of this study were to assess the effects of genomic selection and reduction of the generation interval on the rate of genetic gain and rate of inbreeding. Furthermore, the merit of proven bulls relative to young bulls was studied. This is important for breeding organizations as it determines the relative importance of progeny testing. A closed nucleus breeding scheme was simulated in which 1,000 males and 1,000 females were born annually, 200 bulls were progeny tested, and 20 sires and 200 dams were selected to produce the next generation. In the "proven" (PROV) scenario, only cows with own performance records and progeny-tested bulls were selected as parents. The proportion of the genetic variance that was explained by simulated marker information (M) was varied from 0 to 100%. When M increased from 0 to 100%, the rate of genetic gain increased from 0.238 to 0.309 genetic standard deviations (s) per year (+30%), whereas the rate of inbreeding reduced from 1.00 to 0.42% per generation. Alternatively, when young cows and bulls were selected as parents (YNG scenario), the rate of genetic gain for M=0% was 0.292 s/yr but the corresponding rate of inbreeding increased substantially to 3.15% per generation. A realistic genomic selection scheme (YNG with M=40%) gave 108% higher rate of genetic gain (0.495 s/yr) and approximately the same rate of inbreeding per generation as the conventional system without genomic selection (PROV with M=0%). The rate of inbreeding per year, however, increased from 0.18 to 0.52% because the generation interval in the YNG scheme was much shorter. Progeny-testing fewer bulls reduced the rate of genetic gain and increased the rate of inbreeding for PROV, but had negligible effects for YNG because almost all sires were young bulls. In scenario YNG with M=40%, the best young bulls were superior to the best proven bulls by 1.27 s difference in genomic estimated breeding value. This superiority increased even further when fewer bulls were progeny tested. This stochastic simulation study shows that genomic selection in combination with a severe reduction in the generation interval can double the rate of genetic gain at the same rate of inbreeding per generation, but with a higher rate of inbreeding per year. The number of progeny-tested bulls can be greatly reduced, although this will slightly affect the quality of the proven bull team. Therefore, it is important for breeding organizations to predict the future demand for proven bull semen in light of the increasing superiority of young bulls
Food production, crops and sustainability: restoring confidence in science and technology
Spiertz, J.H.J. - \ 2010
Current Opinion in Environmental Sustainability 2 (2010)5-6. - ISSN 1877-3435 - p. 439 - 443.
agriculture - security - biodiversity - progress - energy - gap
By 2050, the global food requirement will increase significantly, driven by a population increase to more than nine billion and by a richer diet. There is a need for agricultural and food systems that are not only more productive, but also sustainable. Currently, progress is hampered by a lack of understanding how to close the yield and sustainability gap. The consequence is stagnation in implementing policies and regulations that meet future needs. The challenge of meeting global food security in a sustainable way requires a knowledge-intensive approach and the use of advanced technologies. The confidence in modern agrotechnologies and biotechnologies should be restored by sound science, transparency and regulatory institutions
Mitigation of septic shock in mice and rhesus monkeys by human chorionic gonadotrophin-related oligopeptides
Khan (Erasmus MC), N.A. ; Vierboom, M.P.M. ; Holten-Neelen, C. van; Breedveld, E. ; Zuiderwijk-Sick, E. ; Khan, A. ; Kondova, I. ; Braskamp, G. ; Savelkoul, H.F.J. ; Dik, W.A. ; Hart, B.A. 't; Benner, R. - \ 2010
Clinical and Experimental Immunology 160 (2010)3. - ISSN 0009-9104 - p. 466 - 478.
sepsis - pathophysiology - hcg - heterogeneity - inhibition - progress - gender - forms
The marked improvement of several immune-mediated inflammatory diseases during pregnancy has drawn attention to pregnancy hormones as potential therapeutics for such disorders. Low molecular weight fractions derived from the pregnancy hormone human chorionic gonadotrophin (hCG) have remarkable potent immunosuppressive effects in mouse models of diabetes and septic shock. Based on these data we have designed a set of oligopeptides related to the primary structure of hCG and tested these in models of septic shock in mice and rhesus monkeys. We demonstrate that mice exposed to lipopolysaccharide (LPS) and treated subsequently with selected tri-, tetra-, penta- and hepta-meric oligopeptides (i.e. MTR, VVC, MTRV, LQGV, AQGV, VLPALP, VLPALPQ) are protected against fatal LPS-induced septic shock. Moreover, administration of a cocktail of three selected oligopeptides (LQGV, AQGV and VLPALP) improved the pathological features markedly and nearly improved haemodynamic parameters associated with intravenous Escherichia coli-induced septic shock in rhesus monkeys. These data indicate that the designed hCG-related oligopeptides may present a potential treatment for the initial hyperdynamic phase of septic shock in humans
Bio-reduction of pyrite investigated in a gas lift loop reactor
Hol, A. ; Weijden, R.D. van der; Weert, G. van; Kondos, P. ; Buisman, C.J.N. - \ 2010
International Journal of Mineral Processing 94 (2010)3-4. - ISSN 0301-7516 - p. 140 - 146.
bearing arsenian pyrite - gold - oxidation - bioreactor - minerals - progress - part
To liberate gold from refractory pyrite, oxidative destruction techniques that consume lots of energy and generate acidic waste streams are custom. As an alternative the “bio-reduction” of pyrite is proposed and investigated in this study. Bio-reduction is an anaerobic process based on sulfate/sulfur reducing bacteria which are thought to be able to use pyrite-sulfur as a possible electron acceptor. The conversion of pyrite-sulfur into hydrogen sulfide is advantageous because energy is saved and the generation of an acidic waste stream is prevented. In addition, the generated H2S can be used to produce elemental sulfur, or even gold lixiviants such as thiosulfate or bisulfide. Batch experiments under anaerobic conditions showed that two effects can inhibit bio-reduction; methane formation and sulfide accumulation. In a gas lift loop reactor operated at pH 5, temperature of 35 °C, and with continuous sulfide removal no evidence of pyrite bio-reduction was found. Though the sulfate reducing bacteria survived, they did not utilize pyrite-sulfur as an electron acceptor under the chosen conditions.
Valorisation of Jatropha curcas L. plant parts : nut shell conversion to fast pyrolysis oil
Manurung, R. ; Wever, D.A.Z. ; Wildschut, J. ; Venderbosch, R.H. ; Hidayat, H. ; Dam, J.E.G. van; Leijenhorst, E.J. ; Broekhuis, A.A. ; Heeres, H.J. - \ 2009
Food and Bioproducts Processing 87 (2009)3. - ISSN 0960-3085 - p. 187 - 196.
bio-oils - biomass - energy - waste - biofuels - progress - protein - reactor - fuels
The biorefinery concept is a very powerful concept to optimise the conversion of biomass resources to value-added products with a minimum loss of energy and mass and a maximum overall value of the production chain. We here report our activities on the application of this concept to valorise the Jatropha curcas L. (JCL) shrub, a (sub)-tropical plant producing a high quality plant oil that may be converted to biodiesel in good yields. Within a research consortium of Dutch and Indonesian researchers, we are exploring high added value outlets for byproducts of the JCL plant (leaves, latex) and seed processing units (press cake). As an example, we here report fast pyrolysis experiments to convert the nut shells to fast pyrolysis oil, a promising second generation biofuel. The fast pyrolysis experiments were carried out in a continuous bench scale pyrolyser at a throughput of 2.27 kg/h at 480 °C and atmospheric pressure. The nut shell pyrolysis oil was obtained in 50 wt.% yield, the remainder being char (23 wt.%), gas (17 wt.%) and ash. Relevant product properties of the oil were determined and indicate that the oil is inhomogeneous in nature
The European union's 2010 target: Putting rare species in focus
Fontaine, B. ; Bouchet, P. ; Achterberg, K. van; Bongers, A.M.T. - \ 2007
Biological Conservation 139 (2007)1-2. - ISSN 0006-3207 - p. 167 - 185.
ecosystem processes - red list - biodiversity - indicator - alps - coleoptera - progress - density - trends - rarity
The European Union has adopted the ambitious target of halting the loss of biodiversity by 2010. Several indicators have been proposed to assess progress towards the 2010 target, two of them addressing directly the issue of species decline. In Europe, the Fauna Europaea database gives an insight into the patterns of distribution of a total dataset of 130,000 terrestrial and freshwater species without taxonomic bias, and provide a unique opportunity to assess the feasibility of the 2010 target. It shows that the vast majority of European species are rare, in the sense that they have a restricted range. Considering this, the paper discusses whether the 2010 target indicators really cover the species most at risk of extinction. The analysis of a list of 62 globally extinct European taxa shows that most contemporary extinctions have affected narrow-range taxa or taxa with strict ecological requirements. Indeed, most European species listed as threatened in the IUCN Red List are narrow-range species. Conversely, there are as many wide-range species as narrow-range endemics in the list of protected species in Europe (Bird and Habitat Directives). The subset of biodiversity captured by the 2010 target indicators should be representative of the whole biodiversity in terms of patterns of distribution and abundance. Indicators should not overlook a core characteristic of biodiversity, i.e. the large number of narrow-range species and their intrinsic vulnerability. With ill-selected indicator species, the extinction of narrow-range endemics would go unnoticed.
Genetic basis for natural variation in seed vitamin E levels in Arabidopsis thaliana
Gilliland, L.U. ; Magallanes-Lundback, M. ; Hemming, C. ; Suppllee, A. ; Koornneef, M. ; Bentsink, L. ; DellaPenna, D. - \ 2006
Proceedings of the National Academy of Sciences of the United States of America 103 (2006). - ISSN 0027-8424 - p. 18834 - 18841.
tocopherol biosynthesis - environment interactions - plants - mutant - pathway - loci - accumulation - manipulation - dissection - progress
Vitamin E is an essential nutrient for humans and is obtained primarily from food, especially oil, derived from the seed of plants. Genes encoding the committed steps in vitamin E synthesis in plants (VTE, loci 1-5) have been isolated and used for tocopherol pathway engineering with various degrees of success. As a complement to such approaches we have used quantitative trait loci analysis with two sets of Arabidopsis thaliana recombinant inbred lines and have identified 14 QVE (quantitative vitamin E) loci affecting tocopherol content and composition in seeds. Five QVE intervals contain VTE loci that are likely QVE gene candidates. Nine QVE intervals do not contain VTE loci and therefore identify novel loci affecting seed tocopherol content and composition. Several near-isogenic lines containing introgressions of the accession with increased vitamin E levels were shown to confer significantly elevated tocopherol levels compared with the recurrent parent. Fine-mapping has narrowed QVE7 (a gamma-tocopherol quantitative trait loci) to an 8.5-kb interval encompassing two genes. Understanding the basis of the QVE loci in Arabidopsis promises to provide insight into the regulation and/or metabolism of vitamin E in plants and has clear ramifications for improving the nutritional content of crops through marker-assisted selection and metabolic engineering.
An institutional framework for designing and monitoring ecosystem-based fisheries management policy experiments
Rudd, M.A. - \ 2004
Ecological Economics 48 (2004)1. - ISSN 0921-8009 - p. 109 - 124.
integrated coastal management - marine capture fisheries - sustainable development - indicators - performance - governance - principles - guidelines - progress
Indicator systems are seen as central tools for ecosystem-based fisheries management, helping to steer fisheries towards sustainability by providing timely and useful information to decision-makers. Without testing hypotheses about the links between policies and outcomes, however, indicator systems may do little more than promote ad hoc policies, possibly even prolonging the transition to sustainable fisheries. The Institutional Analysis and Development (IAD) framework is a robust framework that has been used extensively to design policy experiments and empirically test theories and models linking ecological–economic systems, institutions and the sustainability of common pool resource systems. A modified IAD framework is developed that transparently encompasses both process-oriented pressure-state-response (PSR) and structurally oriented sustainable livelihood indicator frameworks, thus providing a platform for ecosystem-based fisheries management policy experiment design and monitoring. An institutional approach to fisheries management facilitates critical examination of important cross-cutting issues, including assumptions regarding what comprises sustainability and how market, government and civil society organizations use strategic investments in capital assets and institutions to achieve sustainability objectives. The emphasis on capital assets keeps attention on the relative merits of alternative investment options in policy experiments.
Check title to add to marked list

Show 20 50 100 records per page

Please log in to use this service. Login as Wageningen University & Research user or guest user in upper right hand corner of this page.