294 research outputs found

    Technological Capability and Productivity Growth: An Industrialized / Industrializing Country Comparison

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    The importance of technical change as a crucial element explaining inter-country differences in levels and rates of change in industrial productivity has been increasingly acknowledged. Hence, growing significance has been attached to developing the capability to generate such change. However, the perceived nature of that capability (described here as technological capability) and its links to productivity growth are still poorly understood. This paper empirically explores the links between (i) technological capability (the causal variable) (ii) the generation of technical changes (the intermediate variable) and (iii) productivity growth (the end-result variable). In particular, it examines organizational dimensions of technological capability. L'importance des changements techniques comme Ă©lĂ©ments clĂ©s expliquant les diffĂ©rences entre pays quant aux niveaux et aux taux de productivitĂ© industrielle est de plus en plus reconnue. En consĂ©quence, il y a un intĂ©rĂȘt croissant quant au dĂ©veloppement des capacitĂ©s nĂ©cessaires Ă  de tels changements. Cependant, la nature de cette capacitĂ© (dite capacitĂ© technologique) et ses liens avec la croissance de productivitĂ© est encore peu comprise. Cet article explore empiriquement les liens entre (i) la capacitĂ© technologique (variable causale) (ii) la gĂ©nĂ©ration de changements techniques (variable intermĂ©diaire) et (iii) la croissance de productivitĂ© (variable rĂ©sultante). En particulier, il examine les dimensions organisationnelles de la capacitĂ© technologique.technological capability, organizational systems, technical change, productivity growth, pulp and paper, India, Canada, capacitĂ© technologique, systĂšmes organisationnels, changement technique, croissance de productivitĂ©, pĂątes et papiers, Inde, Canada

    Informal Thinkering: How Is It Important?

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    This paper examines innovation processes or technical change-generation processes at the firm level. It emphasizes the notion that the element of technical and technological change that is a determinant of productivity growth is strongly induced by internal factors related to the firm's behavior, via investment in R&D but also, and importantly, on the basis of informal thinkering within plants. This research is unique in that it seeks first, to examine the pattern of technical change and its ensuing productivity growth, and second, to make a comparison between an industrialized and an industrializing country. This comparison is conducted by empirically comparing mills in the pulp and paper manufacturing sector in two countries: Canada and India. The overall analysis is based on direct observations at the mill level, face-to-face interviews and on analysis of mill documentary records. This paper highlights the importance of managing change as a continuous process. The introduction of intermittent, step-jump technical changes contributed little to explain the differences in performance between the mills. Much more important are (i) the continuing sequences of smaller investments in technical change, often linked to the larger step-jumps, and (ii) the existence of steady streams of changes and improvements that are unrecorded as capital expenditure Cet article examine des processus d'innovation ou de gĂ©nĂ©ration de changements techniques au niveau de la firme. Il met l'emphase sur le fait que les paramĂštres clĂ©s connexes aux changements techniques et technologiques ayant un impact sur la croissance de productivitĂ© sont induits par des facteurs behavioraux internes Ă  la firme. Les changements peuvent ĂȘtre le rĂ©sultat d'investissement dans la R&D,0501s aussi, et de façon significative, le rĂ©sultat de processus de conceptions informelles Ă  l'intĂ©rieur des firmes. Cette recherche examiner dans un premier temps des processus de changements techniques et la croissance de productivitĂ© en rĂ©sultant. Dans un deuxiĂšme temps, elle fait une analyse comparative entre pays industrialisĂ©s et s'industrialisant. Cette Ă©tude empirique est basĂ©e sur des donnĂ©es de premiĂšre0501n (observations directes, entrevues personnelles, documents internes) collectĂ©es dans neuf usines de pĂątes et papiers dans deux pays (Canada et Inde). Ce papier met en Ă©vidence l'importance de gĂ©rer le changement comme un processus continu. L'introduction de changements techniques par sauts intermittents contribue peu Ă  expliquer les diffĂ©rences de croissance de productivitĂ© entre les usines. Plus significatives sont (i) les sĂ©quences continues de petits investissements (changements techniques), souvent liĂ©s aux plus grands changements par sauts, et (ii) l'existence d'un flux continu de changements et d'amĂ©liorations qui ne sont pas officiellement enregistrĂ©s (aux livres, de façon comptable) comme des investissements en capitaux.Technical change, incremental change, performance measure-ment, continuous improvement, capital investment, pulp and paper, India, Canada, Changement technique, changements par incrĂ©ments, mesures de performance, amĂ©lioration continue, investment capital, pĂątes et papiers, Inde, Canada

    Violence in southern Sudan.

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    The Dividing Line between Federal and State Promotion of Aeronautics

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    <p>The model xeno-estrogen bisphenol A (BPA) has been extensively studied over the past two decades, contributing to major advances in the field of endocrine disrupting chemicals research. Besides its well documented adverse effects on reproduction and development observed in rodents, latest studies strongly suggest that BPA disrupts several endogenous metabolic pathways, with suspected steatogenic and obesogenic effects. BPA's adverse effects on reproduction are attributed to its ability to activate estrogen receptors (ERs), but its effects on metabolism and its mechanism(s) of action at low doses are so far only marginally understood. Metabolomics based approaches are increasingly used in toxicology to investigate the biological changes induced by model toxicants and chemical mixtures, to identify markers of toxicity and biological effects. In this study, we used proton nuclear magnetic resonance (<sup>1</sup>H-NMR) based untargeted metabolite profiling, followed by multivariate statistics and computational analysis of metabolic networks to examine the metabolic modulation induced in human hepatic cells (HepG2) by an exposure to low and very low doses of BPA (10<sup>−6</sup>M, 10<sup>−9</sup>M, and 10<sup>−12</sup>M), vs. the female reference hormone 17ÎČ-estradiol (E2, 10<sup>−9</sup>M, 10<sup>−12</sup>M, and 10<sup>−15</sup>M). Metabolomic analysis combined to metabolic network reconstruction highlighted different mechanisms at lower doses of exposure. At the highest dose, our results evidence that BPA shares with E2 the capability to modulate several major metabolic routes that ensure cellular functions and detoxification processes, although the effects of the model xeno-estrogen and of the natural hormone can still be distinguished.</p

    Conductance Distributions in Random Resistor Networks: Self Averaging and Disorder Lengths

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    The self averaging properties of conductance gg are explored in random resistor networks with a broad distribution of bond strengths P(g)\simg^{\mu-1}. Distributions of equivalent conductances are estimated numerically on hierarchical lattices as a function of size LL and distribution tail parameter ÎŒ\mu. For networks above the percolation threshold, convergence to a Gaussian basin is always the case, except in the limit ÎŒ\mu --> 0. A {\it disorder length} ΟD\xi_D is identified beyond which the system is effectively homogeneous. This length diverges as ΟDâˆŒâˆŁÎŒâˆŁâˆ’Îœ\xi_D \sim |\mu|^{-\nu} (Îœ\nu is the regular percolation correlation length exponent) as ÎŒ\mu-->0. This suggest that exactly the same critical behavior can be induced by geometrical disorder and bu strong bond disorder with the bond occupation probability ppÎŒ\mu. Only lattices at the percolation threshold have renormalized probability distribution in a {\it Levy-like} basin. At the threshold the disorder length diverges at a vritical tail strength ÎŒc\mu_c as âˆŁÎŒâˆ’ÎŒc∣−z|\mu-\mu_c|^{-z}, with z=3.2±0.1z=3.2\pm 0.1, a new exponent. Critical path analysis is used in a generalized form to give form to give the macroscopic conductance for lattice above pcp_c.Comment: 16 pages plain TeX file, 6 figures available upon request.IBC-1603-01

    Airborne laser scanning reveals uniform responses of forest structure to moose (Alces alces) across the boreal forest biome

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    1. The moose Alces alces is the largest herbivore in the boreal forest biome, where it can have dramatic impacts on ecosystem structure and dynamics. Despite the importance of the boreal forest biome in global carbon cycling, the impacts of moose have only been studied in disparate regional exclosure experiments, leading to calls for common analyses across a biome-wide network of moose exclosures. 2. In this study, we use airborne laser scanning (ALS) to analyse forest canopy re-sponses to moose across 100 paired exclosure-control experimental plots dis-tributed across the boreal biome, including sites in the United States (Isle Royale), Canada (Quebec, Newfoundland), Norway, Sweden and Finland. 3. We test the hypotheses that canopy height, vertical complexity and above- ground biomass (AGB) are all reduced by moose and that the impacts vary with moose density, productivity, temperature and pulse disturbances such as logging and insect outbreaks. 4. We find a surprising convergence in forest canopy response to moose. Moose had negative impacts on canopy height, complexity and AGB as expected. The responses of canopy complexity and AGB were consistent across regions and did not vary along environmental gradients. The difference in canopy height be-tween exclosures and open plots was on average 6 cm per year since the start of exclosure treatment (±2.1 SD). This rate increased with temperature, but only when moose density was high. 5. The difference in AGB between moose exclosures and open plots was 0.306 Mg ha−1 year−1 (±0.079). In browsed plots, stand AGB was 32% of that in the exclosures, a difference of 2.09 Mg ha−1. The uniform response allows scaling of the estimate to a biome-wide impact of moose of the loss of 448 (±115) Tg per year, or 224 Tg of carbon. 6. Synthesis: Analysis of ALS data from distributed exclosure experiments identified a largely uniform response of forest canopies to moose across regions, facilitat-ing scaling of moose impacts across the whole biome. This is an important step towards incorporating the effect of the largest boreal herbivore on the carbon cycling of one of the world's largest terrestrial biomes.publishedVersio

    Surface Hardness Impairment of Quorum Sensing and Swarming for Pseudomonas aeruginosa

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    The importance of rhamnolipid to swarming of the bacterium Pseudomonas aeruginosa is well established. It is frequently, but not exclusively, observed that P. aeruginosa swarms in tendril patterns—formation of these tendrils requires rhamnolipid. We were interested to explain the impact of surface changes on P. aeruginosa swarm tendril development. Here we report that P. aeruginosa quorum sensing and rhamnolipid production is impaired when growing on harder semi-solid surfaces. P. aeruginosa wild-type swarms showed huge variation in tendril formation with small deviations to the “standard” swarm agar concentration of 0.5%. These macroscopic differences correlated with microscopic investigation of cells close to the advancing swarm edge using fluorescent gene reporters. Tendril swarms showed significant rhlA-gfp reporter expression right up to the advancing edge of swarming cells while swarms without tendrils (grown on harder agar) showed no rhlA-gfp reporter expression near the advancing edge. This difference in rhamnolipid gene expression can be explained by the necessity of quorum sensing for rhamnolipid production. We provide evidence that harder surfaces seem to limit induction of quorum sensing genes near the advancing swarm edge and these localized effects were sufficient to explain the lack of tendril formation on hard agar. We were unable to artificially stimulate rhamnolipid tendril formation with added acyl-homoserine lactone signals or increasing the carbon nutrients. This suggests that quorum sensing on surfaces is controlled in a manner that is not solely population dependent
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