7,557 research outputs found

    Institutional features of wage bargaining in 23 European countries, the US and Japan.

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    This paper presents information on wage bargaining institutions, collected using a standardised questionnaire. Our data provide information from 1995 and 2006, for four sectors of activity and the aggregate economy, considering 23 European countries, plus the US and Japan. Main findings include a high degree of regulation in wage setting in most countries. Although union membership is low in many countries, union coverage is high and almost all countries also have some form of national minimum wage. Most countries negotiate wages on several levels, the sectoral level still being the most dominant, with an increasingly important role for bargaining at the firm level. The average length of collective bargaining agreements is found to lie between one and three years. Most agreements are strongly driven by developments in prices and eleven countries have some form of indexation mechanism which affects wages. Cluster analysis identifies three country groupings of wage-setting institutions.Wage Bargaining ; Institutions ; Indexation ; Trade Union Membership, Cluster Analysis

    Global Identification of Drive Gains and Dynamic Parameters of Parallel Robots - Part 2: Case Study

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    International audienceUsually, identification models of parallel robots are simplified and take only the dynamics of the moving platform into account. Moreover the input efforts are estimated through the use of the manfucaturer's actuator drive gains that are not calibrated thus leading to identification errors. In this paper a systematic way to derive the full dynamic identification model of the Orthoglide parallel robot in combination with a method that allows the identification of both robot inertial parameters and drive gains

    New dry friction model with load- and velocity- dependence and dynamic identification of multi-dof robots

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    International audience— Usually, the joint transmission friction model for robots is composed of a viscous friction force and of a constant dry sliding friction force. However, according to the Coulomb law, the dry friction force depends linearly on the load driven by the transmission, which has to be taken into account for robots working with large variation of the payload or inertial and gravity forces. Moreover, for robots actuating at low velocity, the Stribeck effect must be taken into account. This paper proposes a new inverse dynamic identification model for n degrees of freedom (dof) serial robot, where the dry sliding friction force is a linear function of both the dynamic and the external forces, with a velocity-dependent coefficient. A new sequential identification procedure is carried out. At a first step, the friction model parameters are identified for each joint (1 dof), moving one joint at a time (this step has been validated in [23]). At a second step, these values are fixed in the n dof dynamic model for the identification of all robot inertial and gravity parameters. For the two steps, the identification concatenates all the joint data collected while the robot is tracking planned trajectories with different payloads to get a global least squares estimation of inertial and new friction parameters. An experimental validation is carried out with an industrial 3 dof robot

    Belgium : prehistoric and protohistoric archaeology in the intertidal and subtidal zones of the North Sea

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    The evidence for submerged prehistoric remains and landscapes in the Belgian sector of the North Sea is scarce. The majority of finds dredged and trawled from the seafloor consists of palaeontological material, notably mammalian bone remains, dating from the Early and Late Pleistocene, and possibly the Holocene. Scarce palaeontological and archaeological finds come from the intertidal zone. The available data are rather limited and strikingly sparse compared to neighbouring countries, yet it is steadily growing since the SeArch project. Recent investigations of an area with exceptionally high concentrations of Late Pleistocene and Palaeogene bone finds in the ‘Scheur’ illustrates this development and offers a promising avenue for future research. Growing awareness among a broader public is similarly resulting in an increase in reported chance finds, mainly from beaches. In due course, these growing numbers will hopefully allow quantitative support for certain hypotheses

    CD-1 mice Show Individual Differences in Nicotine Preference in a Modified Two-Bottle Oral Self-Administration Model

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    Although both animal and human studies reveal significant contributions of genetics to smoking addiction, many human studies were underpowered or biased by potential confounding variables, and animal genetic studies are challenged by limited genetic variations and lack of convincing phenotypes. To address these concerns, we used non-sibling outbred CD-1 mice to evaluate individual differences in nicotine preference with a modified two-bottle oral self-administration model. Animals were first given free access to two bottles, one filled with nicotine dissolved in 2% saccharin and the other with saccharin only. Under this regular two-bottle choice condition, the majority of animals avoided the nicotine solution with limited individual differences. However, when we modified the model by introducing 4 days of exposure to 5% saccharin in the drinking water, the animals significantly increased nicotine consumption in the two-bottle choice test, with about 30% animals showing a nicotine preference. Nicotine preference after 5% saccharin treatment remained elevated throughout the 28 days of the experiment. Further, we found there existed striking individual differences in nicotine consumption after exposure to 5% saccharin, with a range of 0–100% of total liquid consumption. The enhanced individual differences and the ratio of nicotine consumption were observed at different concentrations of nicotine (10–80 μg/ml) and in both adolescents and adults. Further examination on the induction mechanism showed that the long-lasting nicotine preference was not correlated with nicotine consumption before the induction, 5% saccharin consumption, or weight gain during the induction. Although liquid consumption during the 4 days of 5% saccharin exposure was decreased by about 30%, comparable liquid restriction alone for 4 days did not induce nicotine preference. Together, this study showed a strong and stable nicotine preference in CD-1 mice, which was induced by a short-term high concentration of saccharin in the drinking water. Considering the nature and heterogeneity of CD-1 mice, the striking individual differences imply that genetics plays an important role in nicotine preference observed in these animals

    Alternative mapping of probes to genes for Affymetrix chips

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    <p>Abstract</p> <p>Background</p> <p>Short oligonucleotide arrays have several probes measuring the expression level of each target transcript. Therefore the selection of probes is a key component for the quality of measurements. However, once probes have been selected and synthesized on an array, it is still possible to re-evaluate the results using an updated mapping of probes to genes, taking into account the latest biological knowledge available.</p> <p>Methods</p> <p>We investigated how probes found on recent commercial microarrays for human genes (Affymetrix HG-U133A) were matching a recent curated collection of human transcripts: the NCBI RefSeq database. We also built mappings and used them in place of the original probe to genes associations provided by the manufacturer of the arrays.</p> <p>Results</p> <p>In a large number of cases, 36%, the probes matching a reference sequence were consistent with the grouping of probes by the manufacturer of the chips. For the remaining cases there were discrepancies and we show how that can affect the analysis of data.</p> <p>Conclusions</p> <p>While the probes on Affymetrix arrays remain the same for several years, the biological knowledge concerning the genomic sequences evolves rapidly. Using up-to-date knowledge can apparently change the outcome of an analysis.</p
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