16 research outputs found

    Estimation and Uncertainty Assessment of Surface Microclimate Indicators at Local Scale Using Airborne Infrared Thermography and Multispectral Imagery

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    A precise estimation and the characterization of the spatial variability of microclimate conditions (MCCs) are essential for risk assessment and site-specific management of vector-borne diseases and crop pests. The objective of this study was to estimate at local scale, and assess the uncertainties of Surface Microclimate Indicators (SMIs) derived from airborne infrared thermography and multispectral imaging. SMIs including Surface Temperature (ST) were estimated in southern Quebec, Canada. The formulation of their uncertainties was based on in-situ observations and the law of propagation of uncertainty. SMIs showed strong local variability and intra-plot variability of MCCs in the study area. The ST values ranged from 290 K to 331 K. They varied more than 17 K on vegetable crop fields. The correlation between ST and in-situ observations was very high (r = 0.99, p = 0.010). The uncertainty and the bias of ST compared to in-situ observations were 0.73 K and ±1.42 K respectively. This study demonstrated that very high spatial resolution multispectral imaging and infrared thermography present a good potential for the characterization of the MCCs that govern the abundance and the behavior of disease vectors and crop pests in a given area

    An implicit method for radiative transfer with the diffusion approximation in SPH

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    An implicit method for radiative transfer in SPH is described. The diffusion approximation is used, and the hydrodynamic calculations are performed by a fully three--dimensional SPH code. Instead of the energy equation of state for an ideal gas, various energy states and the dissociation of hydrogen molecules are considered in the energy calculation for a more realistic temperature and pressure determination. In order to test the implicit code, we have performed non--isothermal collapse simulations of a centrally condensed cloud, and have compared our results with those of finite difference calculations performed by MB93. The results produced by the two completely different numerical methods agree well with each other.Comment: 25 pages, 9 figure

    The seeds of divergence: the economy of French North America, 1688 to 1760

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    Generally, Canada has been ignored in the literature on the colonial origins of divergence with most of the attention going to the United States. Late nineteenth century estimates of income per capita show that Canada was relatively poorer than the United States and that within Canada, the French and Catholic population of Quebec was considerably poorer. Was this gap long standing? Some evidence has been advanced for earlier periods, but it is quite limited and not well-suited for comparison with other societies. This thesis aims to contribute both to Canadian economic history and to comparative work on inequality across nations during the early modern period. With the use of novel prices and wages from Quebec—which was then the largest settlement in Canada and under French rule—a price index, a series of real wages and a measurement of Gross Domestic Product (GDP) are constructed. They are used to shed light both on the course of economic development until the French were defeated by the British in 1760 and on standards of living in that colony relative to the mother country, France, as well as the American colonies. The work is divided into three components. The first component relates to the construction of a price index. The absence of such an index has been a thorn in the side of Canadian historians as it has limited the ability of historians to obtain real values of wages, output and living standards. This index shows that prices did not follow any trend and remained at a stable level. However, there were episodes of wide swings—mostly due to wars and the monetary experiment of playing card money. The creation of this index lays the foundation of the next component. The second component constructs a standardized real wage series in the form of welfare ratios (a consumption basket divided by nominal wage rate multiplied by length of work year) to compare Canada with France, England and Colonial America. Two measures are derived. The first relies on a “bare bones” definition of consumption with a large share of land-intensive goods. This measure indicates that Canada was poorer than England and Colonial America and not appreciably richer than France. However, this measure overestimates the relative position of Canada to the Old World because of the strong presence of land-intensive goods. A second measure is created using a “respectable” definition of consumption in which the basket includes a larger share of manufactured goods and capital-intensive goods. This second basket better reflects differences in living standards since the abundance of land in Canada (and Colonial America) made it easy to achieve bare subsistence, but the scarcity of capital and skilled labor made the consumption of luxuries and manufactured goods (clothing, lighting, imported goods) highly expensive. With this measure, the advantage of New France over France evaporates and turns slightly negative. In comparison with Britain and Colonial America, the gap widens appreciably. This element is the most important for future research. By showing a reversal because of a shift to a different type of basket, it shows that Old World and New World comparisons are very sensitive to how we measure the cost of living. Furthermore, there are no sustained improvements in living standards over the period regardless of the measure used. Gaps in living standards observed later in the nineteenth century existed as far back as the seventeenth century. In a wider American perspective that includes the Spanish colonies, Canada fares better. The third component computes a new series for Gross Domestic Product (GDP). This is to avoid problems associated with using real wages in the form of welfare ratios which assume a constant labor supply. This assumption is hard to defend in the case of Colonial Canada as there were many signs of increasing industriousness during the eighteenth and nineteenth centuries. The GDP series suggest no long-run trend in living standards (from 1688 to circa 1765). The long peace era of 1713 to 1740 was marked by modest economic growth which offset a steady decline that had started in 1688, but by 1760 (as a result of constant warfare) living standards had sunk below their 1688 levels. These developments are accompanied by observations that suggest that other indicators of living standard declined. The flat-lining of incomes is accompanied by substantial increases in the amount of time worked, rising mortality and rising infant mortality. In addition, comparisons of incomes with the American colonies confirm the results obtained with wages— Canada was considerably poorer. At the end, a long conclusion is provides an exploratory discussion of why Canada would have diverged early on. In structural terms, it is argued that the French colony was plagued by the problem of a small population which prohibited the existence of scale effects. In combination with the fact that it was dispersed throughout the territory, the small population of New France limited the scope for specialization and economies of scale. However, this problem was in part created, and in part aggravated, by institutional factors like seigneurial tenure. The colonial origins of French America’s divergence from the rest of North America are thus partly institutional

    The Seeds of Divergence: The Economy of French North America, 1688 to 1760

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    Cadmium and T cell differentiation: Limited impact in vivo but significant toxicity in fetal thymus organ culture

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    International audienceDNA lesions, including oxydated bases, nucleotide damage and double strand breaks, are continuously produced in living cells and represent a threat for genetic stability. Highly conserved repair processes have evolved to maintain DNA integrity. Cadmium (Cd) is an environmental carcinogenic pollutant known to inactivate several proteins involved in DNA repair systems while at the same time creating an oxidative stress that can result in additional DNA lesions. Cd also has potent immunotoxic effects. DNA repair by non-homologous end joining (NHEJ) is absolutely required for T lymphocyte differentiation. In this study, we examined the impact of Cd on non-homologous end joining pathway by analyzing T cell development in the thymus of mice that received Cd-supplemented drinking water. In vivo, the absence of major alteration indicates that Cd does not affect NHEJ, despite its accumulation in the thymus. Cd contamination affects only a discrete population of developing thymocytes. However, these cells are functional as the cellular response observed in mice following gamma-radiation exposure is identical in treated and control mice. Furthermore, Cd diet did not perturb the redox status in thymocytes and more importantly did not generate significant DNA lesions in organs that accumulate the highest concentration of Cd. Our results show that in vivo, Cd does not affect NHEJ or base and nucleotide repair, and that Cd toxicity to T cells is rather linked to cell cycle perturbations

    Néolithisation de la France de l’Ouest : témoignages Villeneuve-Saint-Germain, Cerny et Chambon sur la Loire angevine et atlantique

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    International audienceHistorically, the Loire river is recognized as one of the most remarkable vectors of East-West movements in the northern half of France. This article deals with the question of Neolithic remains discovered for most of them in the river bed; these remains can be dated to the first half of the 5th millenium cal. BC. Today, the sediments are covering most of the settlements which are very well preserved under several meters of sand and gravel.La Loire est historiquement reconnue comme l'un des plus remarquables vecteurs des déplacements est-ouest dans la moitié nord de la France. Cet article abordera la question des vestiges néolithiques majoritairement découverts dans le cours de son lit actuel, vestiges par ailleurs datés de la première moitié du Ve millénaire avant J.-C. L'ampleur des sédimentations occulte à l'heure actuelle la quasi-totalité des habitats fort bien conservés sous plusieurs mètres de sables et graviers
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