963 resultados para Growth-stages


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Low-energy and photoemission electron microscopy enables the determination of facet planes of polycrystalline surfaces and the study of their chemical composition at the sub-m scale. Using these techniques the early oxidation stages of nickel were studied. After exposing the surface to 20 L of oxygen at 373 K a uniform layer of chemisorbed oxygen was found on all facets. After oxygen exposure at 473–673 K, small NiO crystallites are formed on all facets but not in the vicinity of all grain boundaries. The crystallites are separated by areas of bare Ni without significant oxygen coverage.

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The spider crab Pyromaia tuberculata was introduced into southeastern Brazil; ovigerous material was collected and reared in the laboratory. Morphologic changes and growth patterns of post-larval development are reported. Results show that within-stage size variation is lowest in mature stages, especially in the case of females in which there is an apparent size threshold for the last juvenile stages to undergo the puberty molt. A prepuberty molt taking place at the fourth crab stage is indicated by analyzing the allometric growth of the abdomen in females. In contrast, the same procedure using the allometric growth of chelae failed in detecting both the prepuberty and puberty molts in males. Conversely to females, which develop a complex brood chamber at the puberty molt, the enlargement of chelae was not consistent in all postpuberty males. The short instar sequence of this species, in no case exceeding nine stages, is marked by conspicuous morphologic alterations achieved at each molt. Almost all stages can be identified by examining diagnostic features of rostrum, abdomen, sternum, and pleopods.

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Includes bibliography

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We study the impact of the different stages of human capital accumulation on the evolution of labor productivity in a model calibrated to the U.S. from 1961 to 2008. We add early childhood education to a standard continuous time life cycle economy and assume complementarity between educational stages. There are three sectors in the model: the goods sector, the early childhood sector and the formal education sector. Agents are homogenous and choose the intensity of preschool education, how long to stay in formal school, labor effort and consumption, and there are exogenous distortions to these four decisions. The model matches the data very well and closely reproduces the paths of schooling, hours worked, relative prices and GDP. We find that the reduction in distortions to early education in the period was large and made a very strong contribution to human capital accumulation. However, due to general equilibrium effects of labor market taxation, marginal modification in the incentives for early education in 2008 had a smaller impact than those for formal education. This is because the former do not decisively affect the decision to join the labor market, while the latter do. Without labor taxation, incentives for preschool are significantly stronger.

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"New series" vol. IV, no.3.

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"Appendix : containing such plants of the fungi order as have been discovered since the publication of the former volumes" : p. [135-138].

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Objective - The purpose of this study was to assess cardiac function and cell damage in intrauterine growth-restricted (IUGR) fetuses across clinical Doppler stages of deterioration. Study Design - One hundred twenty appropriate-for-gestational-age and 81 IUGR fetuses were classified in stages 1/2/3 according umbilical artery present/absent/reversed end-diastolic blood flow, respectively. Cardiac function was assessed by modified-myocardial performance index, early-to-late diastolic filling ratios, cardiac output, and cord blood B-type natriuretic peptide; myocardial cell damage was assessed by heart fatty acid–binding protein, troponin-I, and high-sensitivity C-reactive protein. Results - Modified-myocardial performance index, blood B-type natriuretic peptide, and early-to-late diastolic filling ratios were increased in a stage-dependent manner in IUGR fetuses, compared with appropriate-for-gestational-age fetuses. Heart fatty acid–binding protein levels were higher in IUGR fetuses at stage 3, compared with control fetuses. Cardiac output, troponin-I, and high-sensitivity C-reactive protein did not increase in IUGR fetuses at any stage. Conclusion - IUGR fetuses showed signs of cardiac dysfunction from early stages. Cardiac dysfunction deteriorates further with the progression of fetal compromise, together with the appearance of biochemical signs of cell damage.

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This paper positions the concept of regional competitiveness within theories concerning regional economic growth and stages of economic development. It examines the sources of regional competitiveness encompassing an analysis based on the particular stage of economic development that the nations within which regions are situated have reached. As a means to achieve this, the paper undertakes an empirical analysis of data stemming from the World Competitiveness Index of Regions, and identifies regional competitiveness as a dual concept that explains relative differences in rates of economic development across regions, as well as an understanding of the future economic growth trajectories of regions at a similar stage of economic development. As with endogenous growth and development theory, the notion of regional competitiveness presented here places knowledge, innovation and entrepreneurship at the forefront of conceptualisations of regional economic differentiation.

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Most tropical fruit flies only lay into mature fruit, but a small number can also oviposit into unripe fruit. Little is known about the link between adult oviposition preference and offspring performance in such situations. In this study we examine the influence of different ripening stages of two mango Mangifera indica L. (Anacardiaceae) varieties on the preference and performance of the Oriental fruit fly, Bactrocera dorsalis (Hendel) (Diptera: Tephritidae), a fly known to be able to develop in unripe fruit. Work was carried out as a series of laboratory-based choice and no-choice oviposition experiments and larval growth trials. In oviposition choice trials, female B. dorsalis demonstrated a preference for ripe fruit of mango variety Namdorkmai over variety Oakrong, but generally the dependent variable most influencing oviposition results was fruit ripening stage. Ripe and fully-ripe mangoes were most preferred for oviposition by B. dorsalis. In contrast, unripe mango was infrequently used by ovipositing females, particularly in choice trials. Consistent with the results of oviposition preference, ripe and fully-ripe mangoes were also best for offspring survival, with a higher percentage of larval survival to pupation and shorter development times in comparison to unripe mango. Changes in Total Soluble Solids, TSS, and skin toughness correlate with changing host use across the ripening stages. Regardless of the mango variety or ripeness stage, B. dorsalis had difficulty penetrating the pericarp of our experimental fruit. Larval survival was also often poor. We discuss the possibility that there may be differences in the ability of laboratory and wild flies to penetrate fruit for oviposition, or that in the field flies more regularly utilize natural fruit wounds as oviposition sites.

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We review and discuss the literature on small firm growth with an intention to provide a useful vantage point for new research studies regarding this important phenomenon. We first discuss conceptual and methodological issues that represent critical choices for those who research growth and which make it challenging to compare results from previous studies. The substantial review of past research is organized into four sections representing two smaller and two larger literatures. The first of the latter focuses on internal and external drivers of small firm growth. Here we find that much has been learnt and that many valuable generalizations can be made. However, we also conclude that more research of the same kind is unlikely to yield much. While interactive and non-linear effects may be worth pursuing it is unlikely that any new and important growth drivers or strong, linear main effects would be found. The second large literature deals with organizational life-cycles or stages of development. While deservedly criticized for unwarranted determinism and weak empirics this type of approach addresses problems of high practical and also theoretical relevance, and should not be shunned by researchers. We argue that with a change in the fundamental assumptions and improved empirical design, research on the organizational and managerial consequences of growth is an important line of inquiry. With this, we overlap with one of the smaller literatures, namely studies focusing on the effects of growth. We argue that studies too often assume that growth equals success. We advocate instead the use of growth as an intermediary variable that influences more fundamental goals in ways that should be carefully examined rather than assumed. The second small literature distinguishes between different modes or forms of growth, including, e.g., organic vs. acquisition-based growth, and international expansion. We note that modes of growth is an important topic that has been under studied in the growth literature, whereas in other branches of research aspects of it may have been studied intensely, but not primarily from a growth perspective. In the final section we elaborate on ways forward for research on small firm growth. We point at rich opportunities for researchers who look beyond drivers of growth, where growth is viewed as a homogenous phenomenon assumed to unambiguously reflect success, and instead focus on growth as a process and a multi-dimensional phenomenon, as well as on how growth relates to more fundamental outcomes.