109 research outputs found

    The Future of Retirement and the Pension System: How the Public's Expectations Vary over Time and across Socio-Economic Groups

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    We analyze expectations of the Dutch population of ages 25 and older concerning the future generosity state and occupational pensions, the two main pillars of the Dutch pension system. Since the summer of 2006, monthly survey data were collected on the expectations of Dutch households concerning purchasing power of occupational pensions, eligibility and purchasing power of old age social security benefits, and the average retirement age ten or twenty years from now. We investigate how these expectations have changed over time and how they vary with socio-economic characteristics. Exploiting the fact that we have data until September 2010, we also analyze the effect of the recent financial and economic crisis. We find significant differences in expectations of different socio-economic groups, mainly suggesting that groups who are probably better informed were also more pessimistic.subjective probabilities, old age social security, occupational pensions

    Patch repair: compatibility issues

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    peer reviewedRepair of any concrete structure results in formation of complex, at least two-component repair systems. Compatibility approach is treated as a basic requirement during selection of repair material. Recently, the understanding for compatibility requirements in repair systems approach is demonstrated in many papers. The aim of this paper is analyzing the compatibility between repair materials and concrete substrate in the case of patch repair. The compatibility issues were discussed in light of the various requirements which determine the mathematical space of loads, including chemical, mechanical and other physical (mainly thermal) loads. N-dimensional compatibility space is created, taking into account selected patch material control parameters. The requirements for good compatibility between repair material and concrete substrate can be formulated by using mathematical inequalities, where the variables are the material control parameters. The effects of properties of the both repair material and concrete substrate were analyzed using computer system ANCOMP developed at Warsaw University of Technology. Usability of this approach was demonstrated using selected case study as an example

    Comparison of Destructive Methods to Appraise the Mechanical Integrity of a Concrete Surface

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    peer reviewedDepending on the technique being used, the concrete removal operation prior to repair can be harmful to the residual concrete skin left on the structure. Whenever a tight bond between the repair and the old concrete is required, the soundness of the prepared surface should thus be assessed. Although this is widely recognized, there is no standard method intended to characterize the integrity of a concrete substrate after concrete removal. This paper presents the results of an investigation intended to assess and compare quantitatively different test methods, namely the Schmidt rebound hammer, the pull-out test and the pull-off test, to evaluate superficial mechanical integrity of a substrate after concrete removal operations. Although it does not yield a precise evaluation of compressive strength, the Schmidt rebound hammer test is recognized as a useful tool for performing quick surveys to assess concrete uniformity. The pull-off test is very well correlated with the splitting-tensile test, but it is not suited for vertical and overhead surfaces. The Capo pull-out test has limited interest for surface preparation, as it is applicable to flat surfaces only. Conversely, the accelerated pull-out test showed interesting potential as a simple and relatively rapid means for assessing the mechanical integrity of a concrete surface prior to repair for any type of concrete surface. More work is definitely required to refine the procedures and develop performance criteria. Nevertheless, it appears from the results generated in this study that the combination Schmidt hammer / pull-off test could fill the needs for the evaluation of horizontal surfaces after concrete removal, while the combination Schmidt hammer / accelerated pull-out test could be used effectively on vertical and overhead surfaces.Coopération scientifique WBI/Québe

    Concrete repair bond: evaluation and factors of influence

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    peer reviewedRepair and strengthening of existing concrete structures are among the biggest challenges civil engineers are facing today and will have to face in the years to come. Present concerns of sustainable development emphasizing repair instead of new construction will only strengthen this trend. Concerted efforts towards improving the durability of concrete repairs are still needed from scientists and engineers. One of the critical aspects of durability of concrete repairs and overlays is lasting and sufficient interfacial bond between repair material and existing concrete substrate. This paper summarizes some of the findings of a collaborative study devoted to the most significant factors influencing bond in repairs (roughness, degree of saturation and carbonation of the substrate) and its field evaluation (type of loading, device misalignment). Based on the test results collected in different test programs, guideline-type recommendations for surface preparation prior to repair were issued

    Transcriptome adaptation of the bovine mammary gland to diets rich in unsaturated fatty acids shows greater impact of linseed oil over safflower oil on gene expression and metabolic pathways

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    Differentially expressed genes implicated in apoptosis of cows in LSO treatment as compared to the same cows on the control diet. Expression direction of several genes predicted to decrease apoptosis. (DOCX 35 kb

    Comparing polycentric configuration for adaptive governance within community forests: Case studies in Eastern North America

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    Looking at two cases of community forests (CF) in Eastern North America, this article examines their institutional features in order to assess whether they are conducive to adaptive governance. To do so, this article presents CFs as manifestations of polycentric governance, which allow identifying the complex networks of relations existing between different actors involved in governance at many scales. Polycentric governance is assumed to have a higher adaptability to changing factors. To better capture the variables conducive to adaptive governance in CFs, we draw on the socio-ecological system (SES) framework. The study shows that variables from the SES framework are useful in identifying features of polycentricity in CFs. Moreover, these variables highlight mechanisms of adaptability in CF governance, namely: interaction between organizations and actors, multiplicity of complementary rules from different organizations and structures of governance. Moreover, ongoing communication with the forest users and learning among actors appear key for CF governance’s adaptability

    Detection of target DNA using fluorescent cationic polymer and peptide nucleic acid probes on solid support

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    BACKGROUND: Nucleic acids detection using microarrays requires labelling of target nucleic acids with fluorophores or other reporter molecules prior to hybridization. RESULTS: Using surface-bound peptide nucleic acids (PNA) probes and soluble fluorescent cationic polythiophenes, we show a simple and sensitive electrostatic approach to detect and identify unlabelled target nucleic acid on microarray. CONCLUSION: This simple methodology opens exciting possibilities for applied genetic analysis for the diagnosis of infections, identification of genetic mutations, and forensic inquiries. This electrostatic strategy could also be used with other nucleic acid detection methods such as electrochemistry, silver staining, metallization, quantum dots, or electrochemical dyes

    Concrete substrate moisture requirements for durable concrete repairs – a field study

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    peer reviewedIn concrete repair specifications, the required moisture condition of the substrate, which can play an important role for bond development, and, ultimately, on the long-term repair / overlay durability, is generally ill-defined and addressed without due consideration to the given substrate characteristics. The standard specification, if any, is to require saturated surface dry (SSD) condition of the substrate prior to application of cementitious repair materials, which is theoretically achieved after saturating the substrate and then letting the surface just start to dry out. This does provide an intuitive solution founded on rational considerations, but it has never really been precisely defined, measured, nor validated. The influence of substrate surface moisture on the bond between the existing concrete and the new repair material is an issue of significant importance. This paper revisits the question, in light of results from a project designed to develop guidelines for moisture conditioning of a concrete substrate prior to a cementitious repair, which was part of a larger effort to develop guidelines for surface preparation of concrete prior to repair. Over the course of the project, multiple series of test slabs were repaired after being subjected to different surface moisture conditioning and then tested for bond strength tests at different ages. The findings are discussed, together with those from previous studies, and recommendations are issued.9. Industry, innovation and infrastructur

    Surfology: concrete substrate evaluation prior to repair

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    peer reviewedThe study of adhesion of repair materials on concrete structures implies a good knowledge of the influence of concrete surface treatment. The effects of surface preparation technique are rarely clearly described and parameterised: it is consequently difficult to point out the real influence of roughness on adhesion results. A large research project has been realized with regards to the influence of concrete substrate strength and preparation technique efficiency. The surface roughness of concrete has been quantified by means of the projection “Moiré” technique, which is an interferometrical measurement method. Comparison between polished, scrabbled and hydro-jetted surfaces evaluation is presented
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