298 research outputs found

    Synchronization of oscillators with long range interaction: phase transition and anomalous finite size effects

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    Synchronization in a lattice of a finite population of phase oscillators with algebraically decaying, non-normalized coupling is studied by numerical simulations. A critical level of decay is found, below which full locking takes place if the population contains a sufficiently large number of elements. For large number of oscillators and small coupling constant, numerical simulations and analytical arguments indicate that a phase transition separating synchronization from incoherence appears at a decay exponent value equal to the number of dimensions of the lattice. In contrast with earlier results on similar systems with normalized coupling, we have indication that for the decay exponent less than the dimensions of the lattice and for large populations, synchronization is possible even if the coupling is arbitarily weak. This finding suggests that in organisms interacting through slowly decaying signals like light or sound, collective oscillations can always be established if the population is sufficiently large.Comment: 15 pages, 12 figures, submitted to Phys. Rev. E; Text slightly changed; References added; Fig. 9 update

    Low-dimensional chaos in populations of strongly-coupled noisy maps

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    We characterize the macroscopic attractor of infinite populations of noisy maps subjected to global and strong coupling by using an expansion in order parameters. We show that for any noise amplitude there exists a large region of strong coupling where the macroscopic dynamics exhibits low-dimensional chaos embedded in a hierarchically-organized, folded, infinite-dimensional set. Both this structure and the dynamics occuring on it are well-captured by our expansion. In particular, even low-degree approximations allow to calculate efficiently the first macroscopic Lyapunov exponents of the full system.Comment: 16 pages, 9 figures. Progress of Theoretical Physics, to appea

    Evaluation of Italian Judicial System

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    Italy is frequently reprimanded by the European Court of Human Rights (ECtHR) over the amount of time it takes Italian courts to reach verdicts. European Court decisions have lead to calls for an urgent intervention in order to save time and costs in Italian judicial system. Efficiency and effectiveness are key targets for managing justice in Italy. Nevertheless they are not easy to achieve. In this paper, using a Stochastic Frontier Model (SFM) we compare the Italian courts efficiency to identify strong and weak points

    The pgip family in soybean and three other legume species: evidence for a birth-and-death model of evolution

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    Polygalacturonase-inhibiting proteins (PGIPs) are leucine-rich repeat (LRR) plant cell wall glycoproteins involved in plant immunity. They are typically encoded by gene families with a small number of gene copies whose evolutionary origin has been poorly investigated. Here we report the complete characterization of the full complement of the pgip family in soybean (Glycine max [L.] Merr.) and the characterization of the genomic region surrounding the pgip family in four legume species. Results: BAC clone and genome sequence analyses showed that the soybean genome contains two pgip loci. Each locus is composed of three clustered genes that are induced following infection with the fungal pathogen Sclerotinia sclerotiorum (Lib.) de Bary, and remnant sequences of pgip genes. The analyzed homeologous soybean genomic regions (about 126 Kb) that include the pgip loci are strongly conserved and this conservation extends also to the genomes of the legume species Phaseolus vulgaris L., Medicago truncatula Gaertn. and Cicer arietinum L., each containing a single pgip locus. Maximum likelihood-based gene trees suggest that the genes within the pgip clusters have independently undergone tandem duplication in each species. Conclusions: The paleopolyploid soybean genome contains two pgip loci comprised in large and highly conserved duplicated regions, which are also conserved in bean, M. truncatula and C. arietinum. The genomic features of these legume pgip families suggest that the forces driving the evolution of pgip genes follow the birth-and-death model, similar to that proposed for the evolution of resistance (R) genes of NBS-LRR-type

    Sedative effects of intramuscular alfaxalone in pet guinea pigs (Cavia porcellus)

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    Objective: To evaluate the efficacy and side effects of alfaxalone administered intramuscularly (IM) as a sedative agent in guinea pigs undergoing survey radiographs

    Surfactant protein A and D polymorphisms and methylprednisolone pharmacogenetics in donor lungs

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    Objective: Surfactant proteins A and D are important molecules involved in lung allograft innate immunity. Genetic polymorphisms of surfactant proteins A and D are associated with various lung diseases. In this study, surfactant protein A and D expression responses were investigated during pharmacogenetics upon methylprednisolone treatment as observed during lung transplantation. Methods: A human cell line (NCI-H441) and precision-cut lung slices from 16 human donors were incubated with methylprednisolone, and surfactant protein A1, surfactant protein A2, and surfactant protein D messenger RNA and surfactant protein A protein expression were assayed. Surfactant protein A1, A2, and D polymorphisms and surfactant protein A gene and protein expressions were determined. Results: In NCI-H441 cells, methylprednisolone treatment at 10−5 M and 10−6 M reduced surfactant protein A1 and surfactant protein A2 messenger RNA and surfactant protein A protein expression (P <.05). A pharmacogenetic relationship was observed in human donor precision-cut lung slices between the surfactant protein A2 (1Ax) variants: Surfactant protein A1, A2, and D messenger RNA expression were greater for 1A0 versus 1A1 (P <.05); surfactant protein A1/surfactant protein A2 genotype 6A26A2/1A01A0 (n = 5) showed greater surfactant protein A1, A2, and D messenger RNA expression and surfactant protein A protein expression compared with the other surfactant protein A1/surfactant protein A2 genotypes (n = 11) (P <.05). Conclusions: The surfactant protein A genotype and methylprednisolone stimuli influence donor lung surfactant protein A and D expression. Lungs carrying the surfactant protein A2 variant 1A0 have a greater expression of surfactant protein A when treated with methylprednisolone. Surfactant protein A polymorphisms could be used to personalize immunosuppressive regimens

    Donor Surfactant Protein A2 Polymorphism and Lung Transplant Survival.

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    Purpose Gene polymorphisms of surfactant proteins, key players in lung innate immunity, have been associated with various lung diseases. The aim of this study was to investigate the potential association between variations within the SP-A gene of the donor lung allograft and recipient post-transplant outcome. Methods Lung-Tx pts (n=192) were prospectively followed by PFTs, bronchoscopies with BAL and biopsies. Donor lungs were assayed for SP-A1 (6An) and SP-A2 (1An) gene polymorphism by using the pyrosequencing method. Unadjusted and adjusted stratified Cox survival models are reported. Results SP-A1 and SP-A2 genotype frequency and lung transplant recipient and donor characteristics as well as the cause of death are noted. Recipients were grouped per donor SP-A2 variants. Individuals that received lungs from donors with the SP-A2 1A0 (n=102) versus 1A1 variant (n=68) or SPA2 genotype 1A01A0 (n=54) versus 1A0A1 (n=38) had greater survival at one year (logrank p<0.025). No significant association was noted for SP-A1 variants. Stratified adjusted survival models for one year survival and diagnosis showed a reduced survival for 1A1 variant and the 1A01A1 genotype. Furthermore, when survival was conditional on one year survival no significance was observed, indicating that the survival difference were due to the first year's outcome associated with the 1A1 variant. Conclusion Donor lung SP-A gene polymorphisms are associated with post-transplant clinical outcome. Lungs from donors with the SP-A2 variant 1A1 had a reduced survival at one year. The observed donor genetic differences, via innate immunity relate to the post-transplant clinical outcome.PURPOSE: Gene polymorphisms of surfactant proteins, key players in lung innate immunity, have been associated with various lung diseases. The aim of this study was to investigate the potential association between variations within the SP-A gene of the donor lung allograft and recipient post-transplant outcome. METHODS: Lung-Tx pts (n=192) were prospectively followed by PFTs, bronchoscopies with BAL and biopsies. Donor lungs were assayed for SP-A1 (6An) and SP-A2 (1An) gene polymorphism by using the pyrosequencing method. Unadjusted and adjusted stratified Cox survival models are reported. RESULTS: SP-A1 and SP-A2 genotype frequency and lung transplant recipient and donor characteristics as well as the cause of death are noted. Recipients were grouped per donor SP-A2 variants. Individuals that received lungs from donors with the SP-A2 1A0 (n=102) versus 1A1 variant (n=68) or SPA2 genotype 1A01A0 (n=54) versus 1A0A1 (n=38) had greater survival at one year (logrank p<0.025). No significant association was noted for SP-A1 variants. Stratified adjusted survival models for one year survival and diagnosis showed a reduced survival for 1A1 variant and the 1A01A1 genotype. Furthermore, when survival was conditional on one year survival no significance was observed, indicating that the survival difference were due to the first year's outcome associated with the 1A1 variant. CONCLUSION: Donor lung SP-A gene polymorphisms are associated with post-transplant clinical outcome. Lungs from donors with the SP-A2 variant 1A1 had a reduced survival at one year. The observed donor genetic differences, via innate immunity relate to the post-transplant clinical outcome
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