4,217 research outputs found
Generalized minority games with adaptive trend-followers and contrarians
We introduce a simple extension of the minority game in which the market
rewards contrarian (resp. trend-following) strategies when it is far from
(resp. close to) efficiency. The model displays a smooth crossover from a
regime where contrarians dominate to one where trend-followers dominate. In the
intermediate phase, the stationary state is characterized by non-Gaussian
features as well as by the formation of sustained trends and bubbles.Comment: 4 pages, 6 figure
Assays of the Metabolic Viability of Single Giant Mitochondria. Experiments with Intact and Impaled Mitochondria
Single giant mitochondria isolated from mice fed cuprizone were assayed for their metabolic viability. Two tests were devised. One test optically detected the accumulation of calcium phosphate within the mitochondria under massive loading conditions (including the presence of succinate and ATP). The accumulation corresponds to a test of energy coupling from either electron transport or the hydrolysis of ATP since it is blocked by either antimycin A or oligomycin. The other assay tested for the production of ATP from ADP and Pi, using myofibrils. Myofibrils prepared from glycerinated rabbit psoas muscle contract only in the presence of ATP and not in the presence of ADP. Myofibrillar contraction is unaffected by the presence of antimycin A or oligomycin. However, myofibrils in the presence of mitochondria that are phosphorylating ADP to ATP do contract. This contraction is blocked by antimycin A and/or oligomycin. Hence, the ATP which causes myofibrillar contraction is produced by oxidative phosphorylation. At low mitochondrial concentration, only the myofibrils in close proximity with mitochondria contract in the presence of ADP. Therefore the assay can be used to test the viability of individual mitochondria. Individual giant mitochondria were found to be viable, using both of these assays. Comparable results were obtained in mitochondria impaled with microelectrodes. The potentials and resistances were unaffected by concomitant calcium phosphate accumulation or oxidative phosphorylation
Parts de marché et spécialisation commerciale de l’Allemagne, de la France et de l’Italie.
parts de marché, spécialisation commerciale.
Maintenance of primary cell cultures of immunocytes from Cacopsylla spp. psyllids: a new in vitro tool for the study of crop pest insects
Insetos associados às sementes e frutos de espécies da arborização de Curitiba, PR.
Resumo
The multifaceted nature of aminopeptidases ERAP1, ERAP2, and LNPEP: from evolution to disease
In the human genome, the aminopeptidases ERAP1, ERAP2 and LNPEP lie contiguously on chromosome 5. They share sequence homology, functions and associations with immune-mediated diseases. By analyzing their multifaceted activities as well as their expression in the zoological scale, we suggest here that the progenitor of the three aminopeptidases might be LNPEP from which the other two aminopeptidases could have derived by gene duplications. We also propose that their functions are partially redundant. More precisely, the evolutionary story of the three aminopeptidases might have been dictated by their role in regulating the renin–angiotensin system, which requires their controlled and coordinated expression. This hypothesis is supported by the many species that lack one or the other gene as well as by the lack of ERAP2 in rodents and a null expression in 25% of humans. Finally, we speculate that their role in antigen presentation has been acquired later on during evolution. They have therefore been diversified between those residing in the ER, ERAP1 and ERAP2, whose role is to refine the MHC-I peptidomes, and LNPEP, mostly present in the endosomal vesicles where it can contribute to antigen cross-presentation or move to the cell membrane as receptor for angiotensin IV. Their association with autoinflammatory/autoimmune diseases can therefore be two-fold: as “contributors” to the shaping of the immune-peptidomes as well as to the regulation of the vascular response
An Investigation into Land Use Changes and Consequences in the Northern Great Plains Using Systems Thinking and Dynamics
From 1997 to 2007, 9.6 million hectares of grassland were converted to cropland and fifty seven percent of these conversions occurred in the Northern Great Plains (NGP). Since 2007, another 9.5 million U.S. hectares have been converted with the majority located in the NGP. Shortterm, positive benefits include increased food production and higher financial returns to farmers. However, there could be unintended consequences through loss of ecosystem services. Consequences may include compromised water quality, wildlife habitat loss/fragmentation, and decreased carbon sequestration. The principal objective of this work is to: 1) identify structural features influencing land use decisions through agricultural stakeholder engagement; and 2) to synthesize results into a causal loop diagram through a group model building process. This information can be used to construct a stock-flow model to quantify implications for land management, forecast potential unintended consequences from major land use changes, and develop strategies to minimize their impacts
Ultrasound and Microwave-assisted Extraction of Proteins from Coffee Green Beans: Effects of Process Variables on the Protein Integrity
The demand for proteins is constantly increasing and green extraction methodologies are needed to achieve environmental sustainability goals. The recovery of the by-products of the agri-food chain has also become a priority from a circular economy perspective. Some by-products are still little exploited for the extraction of proteins, such as coffee by-products. In this work, various innovative extraction technologies were applied to recover the protein fraction from the non-compliant coffee green beans (CGB), using a methodological approach that allowed to correlate the process parameters with the final quality of the extracted proteins. The ultrasound-assisted extraction (UAE) technique has been shown to have a minor impact on the quality of the proteins, thanks to the possibility of refrigerating the system, while the microwave-assisted extraction (MAE) shows a certain degree of degradation due to the high temperatures reached. The results indicate that strict temperature control is required during alkaline extraction to preserve the quality of the protein fraction
Make Bow-tie Dynamic by Rethinking it as a Hierarchical Bayesian Network. Dynamic Risk Assessment of an LNG Bunkering Operation
In the present era, the spread of cyber-physical systems in the framework of the so-called Industry 4.0, is leading towards a complete automation of industrial processes, which are increasingly decentralized, smart, and require fewer and fewer frontline personnel. The risk assessment process is certainly not excluded from the revolution, and in perspective needs to be automatic, dynamic and linked with the conditions that emerge, moment by moment, in the life of a complex system. Analytical techniques can help in converting data in information and hence system knowledge to spot trends in operational performance, thus improving risk assessment quality. Even though the bow-tie approach is widely used within the context of complex systems, it still evidences several limitations, mainly connected to the actual assessment of likelihood and interdependencies in the fault and event trees. This paper shows how a bow tie analysis can be reframed as a Hierarchical Bayesian Network, where the probability distributions of the network nodes are updated with real time predictions during the operations. The proposed model was then applied to the risk assessment of a shore-to-ship LNG bunkering operation
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