1,252 research outputs found
Citizens' demand for permits and Kwerel''s incentive compatible mechanism for pollution control
An interesting feature of pollution permit markets is that citizens may purchase permits to directly lower the levels of pollution. Kwerel's mechanism (Review of Economic Studies~1977) is not incentive compatible when citizens demand permits. We show that a modification of Kwerel''s mechainism, the minimum-price mechanism, is incentive compatible when citizens demand permits, even in the case where there is uncertainty about the damages from pollution.
Security models for trusting network appliances
A significant characteristic of pervasive computing is the need for secure interactions between highly mobile entities and the services in their environment. Moreover,these decentralised systems are also characterised by partial views over the state of the global environment, implying that we cannot guarantee verification of the properties of the mobile entity entering an unfamiliar domain. Secure in this context encompasses both the need for cryptographic security and the need for trust, on the part of both parties, that the interaction is functioning as expected. In this paper we make a broad assumption that trust and cryptographic security can be considered as orthogonal concerns (i.e. cryptographic measures do not ensure transmission of correct information). We assume the existence of reliable encryption techniques and focus on the characteristics of a model that supports the management of the trust relationships between two devices during ad-hoc interactions
Stochastic Dominance Analysis of Bioenergy Crops as a Production Alternative on an East Tennessee Beef and Crop Farm
This study evaluated prices and incentives for switchgrass stated in a biorefinery’s contract terms that induce switchgrass production on an east Tennessee representative farm when compared with traditional enterprises. The alternate contract terms imitated current subsidies/incentives offered as well as incentives and cost share terms not in the BCAP.switchgrass, contract, risk aversion, net return, Farm Management, Production Economics, Resource /Energy Economics and Policy, Q12,
Trust dynamics for collaborative global computing
Recent advances in networking technology have increased the potential for dynamic enterprise collaborations between an open set of entities on a global scale. The security of these collaborations is a major concern, and requires novel approaches suited to this new environment to be developed. Trust management appears to be a promising approach. Due to the dynamic nature of these collaborations,dynamism in the formation, evolution and exploitation of trust is essential. In this paper we explore the properties of trust dynamics in this context. Trust is formed and evolves according to personal experience and recommendations. The properties of trust dynamics are expressed through a formal model of trust. Specific examples, based on an e-purse application scenario are used to demonstrate these properties
Autonomous Sweet Pepper Harvesting for Protected Cropping Systems
In this letter, we present a new robotic harvester (Harvey) that can
autonomously harvest sweet pepper in protected cropping environments. Our
approach combines effective vision algorithms with a novel end-effector design
to enable successful harvesting of sweet peppers. Initial field trials in
protected cropping environments, with two cultivar, demonstrate the efficacy of
this approach achieving a 46% success rate for unmodified crop, and 58% for
modified crop. Furthermore, for the more favourable cultivar we were also able
to detach 90% of sweet peppers, indicating that improvements in the grasping
success rate would result in greatly improved harvesting performance
Tissue Inhibitor of Metalloproteinase–3 (TIMP-3) induces FAS dependent apoptosis in human vascular smooth muscle cells
Over expression of Tissue Inhibitor of Metalloproteinases-3 (TIMP-3) in vascular smooth muscle cells (VSMCs) induces apoptosis and reduces neointima formation occurring after saphenous vein interposition grafting or coronary stenting. In studies to address the mechanism of TIMP-3-driven apoptosis in human VSMCs we find that TIMP-3 increased activation of caspase-8 and apoptosis was inhibited by expression of Cytokine response modifier A (CrmA) and dominant negative FAS-Associated protein with Death Domain (FADD). TIMP-3 induced apoptosis did not cause mitochondrial depolarisation, increase activation of caspase-9 and was not inhibited by over-expression of B-cell Lymphoma 2 (Bcl2), indicating a mitochondrial independent/type-I death receptor pathway. TIMP-3 increased levels of the First Apoptosis Signal receptor (FAS) and depletion of FAS with shRNA showed TIMP-3-induced apoptosis was FAS dependent. TIMP-3 induced formation of the Death-Inducing Signalling Complex (DISC), as detected by immunoprecipitation and by immunofluorescence. Cellular-FADD-like IL-1 converting enzyme-Like Inhibitory Protein (c-FLIP) localised with FAS at the cell periphery in the absence of TIMP-3 and this localisation was lost on TIMP-3 expression with c-FLIP adopting a perinuclear localisation. Although TIMP-3 inhibited FAS shedding, this did not increase total surface levels of FAS but instead increased FAS levels within localised regions at the cell surface. A Disintegrin And Metalloproteinase 17 (ADAM17) is inhibited by TIMP-3 and depletion of ADAM17 with shRNA significantly decreased FAS shedding. However ADAM17 depletion did not induce apoptosis or replicate the effects of TIMP-3 by increasing localised clustering of cell surface FAS. ADAM17-depleted cells could activate caspase-3 when expressing levels of TIMP-3 that were otherwise sub-apoptotic, suggesting a partial role for ADAM17 mediated ectodomain shedding in TIMP-3 mediated apoptosis. We conclude that TIMP-3 induced apoptosis in VSMCs is highly dependent on FAS and is associated with changes in FAS and c-FLIP localisation, but is not solely dependent on shedding of the FAS ectodomain
Genotypic Variation in Constitutive and Induced Resistance in Grapes against Spider Mite (Acari: Tetranychidae) Herbivores
We examined genotypic variation in constitutive and induced resistance in grapes against Willamette spider mites, Eotetranychus willametti Ewing, and Pacific spider mites, Tetranychus pacificus McGregor, 2 common species of tetranychid mites found in California vineyards. We found evidence that early-season injury by Pacific mites induced resistance against subsequent Willamette mite populations but early-season injury by Willamette mites did not induce resistance against subsequent Willamette mite populations. Significant levels of induction were detected for several cultivars of the Old World species Vitis vinifera L. as well as the North American species V. calif arnica Bentham. Phylogenetic relationships among grape genotypes explained little of the variation we observed in induced resistance. Phylogenetic relatedness among grapes did help explain patterns of constitutive resistance for Pacific mites; cultivars of V. vinifera L. tended to be susceptible, whereas North American species were resistant. Wi11amette mites, however, performed well on some Old World cultivars and 2 North American species of Vitis that are native to California. We did not find any strong evidence of a negative correlation between constitutive resistance and strength of induction for these grape genotypes. Our results show that several factors contribute to variation in constitutive and induced resistance in grapes against these 2 species of spider mites, including grape genotype, previous history of mite injury (induction), the species of mite causing previous injury, and to some extent, phylogenetic relatedness among grapes. We also suspect that mite genotype has important influence
Mineral Acquisition from Clay by Budongo Forest Chimpanzees
Chimpanzees of the Sonso community, Budongo Forest, Uganda were observed eating clay and drinking clay-water from waterholes. We show that clay, clay-rich water, and clay obtained with leaf sponges, provide a range of minerals in different concentrations. The presence of aluminium in the clay consumed indicates that it takes the form of kaolinite. We discuss the contribution of clay geophagy to the mineral intake of the Sonso chimpanzees and show that clay eaten using leaf sponges is particularly rich in minerals. We show that termite mound soil, also regularly consumed, is rich in minerals. We discuss the frequency of clay and termite soil geophagy in the context of the disappearance from Budongo Forest of a formerly rich source of minerals, the decaying pith of Raphia farinifera palms
Chromosome Abnormalities and Repeated Abortion: A Preliminary Report
In view of the increased frequency of chromosome rearrangements demonstrated in these couples and the importance of counseling for future pregnancies, it would be wise to consider cytogenetic evaluation when all other probable causes for recurrent abortion have been ruled out
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