3,956 research outputs found
Damage Potential of Rose Chafer and Japanese Beetle (Coleoptera: Scarabaeidae) in Michigan Vineyards
Responses of young non-fruiting grapevines, Vitis labrusca (L.) var. ‘Niagara’, to defoliation were examined at two stages of vine growth when beetles typically infest vineyards. In the first experiment, vines were caged and subjected to two weeks of feeding by 0, 10, 20, or 40 adult Macrodactylus subspinosus Fabricius (Scarabaeidae: Macrodactylini) during bloom, or to the same range of adult Popillia japonica Newman (Scarabaeidae: Anomalini) during veráison, when berries begin changing color. Leaf area removed increased with beetle density, but less than 1% of the leaf area was removed at the highest density of M. subspinosus, and less than 7% at the highest density of P. japonica. Vine growth measurements taken during the year of injury and prior to bloom during the following season indicated no significant impacts of this leaf injury on vegetative growth. In the second experiment, mechanical injury was induced by removing 0, 10, 20, or 30% of the total leaf area of every fully expanded leaf at bloom or veráison. A significant effect of mechanical injury at bloom was found on cane diameters when measured at veráison, indicating that a carbon source limitation was induced in these vines. By the time of leaf loss, cane diameters were not significantly different across treatments, indicating that vines may have been able to compensate for the earlier defoliation. Injury at veráison had no significant effect on vine growth parameters. These results suggest that young ‘Niagara’ vines are able to tolerate foliar injury far exceeding that caused by two weeks of exposure to 40 beetles of either species. Surveys of Michigan vineyards containing different grape varieties indicated that although both beetle species could be found in high abundance, leaf injury levels were low. The implications for management of beetle foliar herbivory in vineyards are discussed
The Role Of Tax And Transfers In Reducing Personal Income Inequality In EuropeÃs Regions: Evidence From EUROMOD
In this paper we use statistical tools and graphic devices in order to give a comprehensive picture of income inequality levels in a set of 100 EU-15 regions at the end of the XX century before and after the operation of the tax-benefit. Our analysis is based on EUROMOD, the first multi-country tax-benefit model built with a common framework that includes detailed information on taxes and benefits paid and received by individuals and/or households from samples that are representative for the 15 EU countries. Our analysis focuses on intraregional inequality and it explores the relationship between regional inequality levels (both in market incomes and disposable incomes) and economic performance. Our main findings indicate that tax-benefits systems in Europe notably reduce market inequality in all EU regions and that the size of this reduction (i.e. redistributive effect) depends crucially on (i) the market inequality level of the region (positively), (ii) the relative economic performance of the region in the country (negatively) and (iii) the country to which the region belongs.European Union, Regions, inequality, redistribution, economic performance
Income inequality comparisons with dirty data: the UK and Spain during the 1980s
Inequality comparisons between countries and over time should take into account problems of data imperfection. We examine the contrasting experience of the UK and Spain during the 1980s in terms of the distribution of disposable income. We consider whether the apparent divergence in inequality could be attributable to deficiencies in income data including under-reporting
Extending the scope of models for large-scale structure formation in the Universe
We propose a phenomenological generalization of the models of large-scale
structure formation in the Universe by gravitational instability in two ways:
we include pressure forces to model multi-streaming, and noise to model
fluctuations due to neglected short-scale physical processes. We show that
pressure gives rise to a viscous-like force of the same character as that one
introduced in the ``adhesion model'', while noise leads to a roughening of the
density field yielding a scaling behavior of its correlations.Comment: matches published version in A&A, incl. 3 figure
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