The influence of plant fertilisation regime on plant-aphid-parasitoid interactions

This thesis examines effects of plant fertilisation regime on herbivore and parasitoid performance for two aphids, Macrosiphum euphorbiae and Myzus persicae, and one parasitoid wasp, Aphidius ervi. Herbivore performance was measured as adult fresh weight and intrinsic rate of increase. Parasitoid performance was measured as length of hind tibia, sex ratio, and in a series of choice experiments also parasitoid development time and parasitization rate was measured. Comparisons were made between the performance of M. euphorbiae on two different plant species, petunia and sweet pepper, between the performance of the aphids M. euphorbiae and M. persicae on sweet pepper, and between the performance of A. ervi in M. euphorbiae and in M. persicae on sweet pepper. The performance of M. euphorbiae was better on petunia than on sweet pepper. On petunia a positive effect of plant content of potassium and indications of a positive effect of nitrogen fertilisation were found while on sweet pepper both nitrogen and of potassium had negative influence. On both plant species, however, a negative influence of sulphur was found. The two aphid species reacted differently to fertilisation and plant content of nutrients. For M. euphorbiae fresh weight was decreased by fertilisation while for M. persicae the influence varied with experiment. For M. persicae a high N:K ratio was favourable while for M. euphorbiae plant contents of N and K were both negative. Plant content of sulphur and potassium influenced tibia length of A. ervi positively in M. euphorbiae. In M. persicae plant fertilisation was positive but the composition of the plant fertilisation did not seem important for the parasitoid. Plant fertilisation enhanced parasitization rate in M. euphorbiae but not in M. persicae. Parasitoid performance was, however, more improved by fertilisation in M. persicae than in M. euphorbiae. The parasitoid both preferred, and developed faster in, M. persicae compared to M. euphorbiae. The results of this study show that it is possible to influence both aphid performance and performance of A. ervi with plant fertilisation but the influence varies with both plant and aphid species

CSR Practice in the Drc's Mining Sector by Chinese Firms

The author analyses the CSR practice in mining area by Chinese firm

The treatment of surface run-off waters from an equine paddock area with ferric sulphate

The Finnish horse industry has been growing with about 1000 horses annually. It has been assessed that there are about 35 000 paddocks for 70 000 horses. The trampling of horses increases the risk for surface run-off from the paddocks and the faeces also make them critical source fo phosphorus. A chemical method for treatment of run-off water from a paddock was tested in Ypäjä (SW, Finland)

Non-invasive single-bunch matching and emittance monitor

On-line monitoring of beam quality for high brightness beams is only possible using non-invasive instruments. For matching measurements, very few such instruments are available. One candidate is a quadrupole pick-up. Therefore, a new type of quadrupole pick-up has been developed for the 26 GeV Proton Synchrotron (PS) at CERN, and a measurement system consisting of two such pick-ups is now installed in this accelerator. Using the information from these pick-ups, it is possible to determine both injection matching and emittance in the horizontal and vertical planes, for each bunch separately. This paper presents the measurement method and some of the results from the first year of use, as well as comparisons with other measurement methods.Comment: 10 pages, 10 figures; added figure, minor textual additions; To be resubmitted to Phys. Rev. ST-A

The Dynamics of External Financing

A dynamic process underlying firms' discrete financial choices has previously been found, but without controlling for unobserved heterogeneity, this dependence can either be of a "true" nature or an effect of firm-specific characteristics that we cannot observe. This study extends previous research focusing on firms' discrete external financing decision by adapting a model by Honoré and Kyriazidou (2000), which accommodates both fixed effects and a lagged dependent variable, which makes it possible to establish the nature of the dependence. We find that there is a smoothing of financing, even after controlling for unobserved heterogeneity, and also that unobserved heterogeneity plays a significant explanatory role.Corporate finance; Discrete choice; State dependence

Two ways of estimating a transport model

In this article, it is shown how the parameters of a transport model can be estimated in a way that, in contrast to previously used methods, utilizes regional prices as well as of trade costs. The proposed method uses bi-level programming to minimize a weighted least squares' criterion under the restriction that the estimated parameters satisfy the Kuhn-Tucker conditions for an optimal solution of the transport model. We use Monte-Carlo simulations to trace out some properties of the estimator and compare it with a traditional calibration method. The analysis shows that the proposed technique estimates prices as well as trade costs more efficiently.Public Economics,

Sovereign Debt Restructuring: A Model-Law Approach

The existing contractual framework for sovereign debt restructuring is sorely inadequate. Whether or not their fault, nations sometimes take on debt burdens that become unsustainable. Until resolved, the resulting sovereign debt problem hurts not only those nations (such as Greece) but also their citizens, their creditors, and—by posing serious systemic risks to the international financial system—the wider economic community. The existing contractual framework functions poorly to resolve the problem because it often leaves little alternative between a sovereign debt bailout, which is costly and creates moral hazard, and a default, which raises the specter of systemic financial contagion. Most observers therefore want to strengthen the legal framework for resolving sovereign debt problems. International organizations, including the United Nations, have been contemplating strengthening that framework through treaties. The political economy of treaty-making, however, makes that approach highly unlikely to succeed in the near future. This article argues, in contrast, that a model-law approach should not only strengthen that legal framework but also should be politically and economically feasible. Model laws have long been used in cross-border lawmaking, but they are different than treaties. Unlike a treaty, a model law would not require general acceptance for its implementation. Only one or two jurisdictions, for example, need enact the text of this article’s proposed model law for it to become widely effective. Once that occurs, a debtor-state whose debt contracts are governed by those jurisdictions’ laws, or by its own laws, could restructure that debt without needing to amend any of those contracts. A model-law approach should also be desirable. This article’s model law, for example, would reduce uncertainty and should also achieve significant cost advantages—both to debtor-states and to their creditors—over the sovereign-debt-restructuring status quo. Because it would require only a ministerial supervisory process, the model law would not interfere with the exercise of a sovereign’s political discretion. Moreover, the model law provides incentives to motivate fair bargaining on behalf of debtor-states and their creditors, while restricting rent-seeking holdouts. It also enables the type of interim funding of day-to-day debts that a debtor-state needs during its debt restructuring. Debtor-states should therefore want (and creditors, other than rent-seeking holdouts, should want them) to enact into law this article’s proposed model-law text. Regardless of whether that enactment occurs, however, the article should serve its underlying purpose: to provide a conceptual and legal analysis of how a model law could be structured and how a model-law approach could be used to solve the problem of unsustainable sovereign debt burdens, and to help develop the norms required to facilitate those goals

Mechanical characterization and modeling of non-linear deformation and fracture of a fiber reinforced metal matrix composite

The nonlinear anisotropic mechanical behavior of an aluminum alloy metal matrix composite reinforced with continuous alumina fibers was determined experimentally. The mechanical behavior of the composite were modeled by assuming that the composite has a periodical microstructure. The resulting unit cell problem was solved with the finite element method. Excellent agreement was found between theoretically predicted and measured stress-strain responses for various tensile and shear loadings. The stress-strain responses for transverse and inplane shear were found to be identical and this will provide a simplification of the constitutive equations for the composite. The composite has a very low ductility in transverse tension and a limited ductility in transverse shear that was correlated to high hydrostatic stresses that develop in the matrix. The shape of the initial yield surface was calculated and good agreement was found between the calculated shape and the experimentally determined shape