540 research outputs found

    The matrix Kadomtsev--Petviashvili equation as a source of integrable nonlinear equations

    Full text link
    A new integrable class of Davey--Stewartson type systems of nonlinear partial differential equations (NPDEs) in 2+1 dimensions is derived from the matrix Kadomtsev--Petviashvili equation by means of an asymptotically exact nonlinear reduction method based on Fourier expansion and spatio-temporal rescaling. The integrability by the inverse scattering method is explicitly demonstrated, by applying the reduction technique also to the Lax pair of the starting matrix equation and thereby obtaining the Lax pair for the new class of systems of equations. The characteristics of the reduction method suggest that the new systems are likely to be of applicative relevance. A reduction to a system of two interacting complex fields is briefly described.Comment: arxiv version is already officia

    A numerical study of planar arrays of correlated spin islands

    Full text link
    We present our analysis of a system of interacting islands of XY spins on a triangular lattice that has been introduced a few years ago by Eley et al. to account for the phenomenology in experiments on tunable arrays of proximity coupled long superconductor-normal metal-superconductor junctions. The main features of the model are the separation of a local and a global interaction energy scale and the mesoscopic character of the spin islands. Upon lowering the temperature the model undergoes two crossovers corresponding to an increasing phase coherence on a single island and to the onset of global coherence across the array; the latter is a thermodynamical phase transition in the Ising universality class. The dependence of the second transition on the island edge-to-edge spacing is related to the proximity-effect of the coupling constant.Comment: 6 pages, 5 figures, accepted for publication in EPJ

    Classical Lie symmetries and reductions of a nonisospectral Lax pair

    Full text link
    The classical Lie method is applied to a nonisospectral problem associated with a system of partial differential equations in 2+1 dimensions (Maccari A, J. Math. Phys. 39, (1998), 6547-6551). Identification of the classical Lie symmetries provides a set of reductions that give rise to different nontrivial spectral problems in 1+1 dimensions. The form in which the spectral parameter of the 1+1 Lax pair is introduced is carefully described.Comment: 11 pages (v2: A typo corrected in the authors' names

    Shipbuilding 4.0 Index Approaching Supply Chain

    Get PDF
    The shipbuilding industry shows a special interest in adapting to the changes proposed by the industry 4.0. This article bets on the development of an index that indicates the current situation considering that supply chain is a key factor in any type of change, and at the same time it serves as a control tool in the implementation of improvements. The proposed indices provide a first definition of the paradigm or paradigms that best fit the supply chain in order to improve its sustainability and a second definition, regarding the key enabling technologies for Industry 4.0. The values obtained put shipbuilding on the road to industry 4.0 while suggesting categorized planning of technologies

    A methodological approach to upscale toward an agroecology system in EU-LAFSs: The case of the parma bio-district

    Get PDF
    The increasing interest in bio-districts is part of the debate on the capacity to integrate agri-food systems and territory in order to improve the quality of life in rural communities. Considering the goals of developing and promoting an innovative territorial rural development approach, the bio-district can become a process toward a more sustainable model represented by the agroecological agriculture system. The paper presents a case study of the Parma bio-district through the approach of a Localized Agri Food System (LAFS) to verify whether bio-districts can be a tool for scaling up towards agroecology. Stakeholder classification and analysis are conducted using an influence-interest matrix. We identified four groups of stakeholders in relation to their interests and power to influence the process. In the case of the Parma bio-district the role of local institutions in dialogue with consumers and producers' associations is crucial for success. We conclude that bio-districts can be a tool for a scaling-up towards agroecology since they can facilitate a synergetic relation between organic and agroecological agriculture, spreading organic agriculture more widely around the local area. However, the involvement of a wide variety of different stakeholders means that governance is a key element in facilitating "cross fertilization" and preventing the process from becoming purely formulaic

    Estudo comparativo de delineamentos experimentais para estimativas de parâmetros genéticos em erva-mate Ilex paraguariensis A. St. Hil..

    Get PDF
    O presente trabalho teve por objetivo comparar a eficiência do látice em relação aos delineamentos em blocos casualizados (DBC) e inteiramente casualizados (DIC) quanto aos caracteres altura e produção de massa verde em erva-mate (Ilex paraguariensis A. St. - Hil.). O experimento, conduzido na Fazenda Experimental do Canguiri, da Universidade Federal do Paraná, em Pinhais, PR, foi composto de cinco procedências, quatro com 13 e uma com 12 progênies de meias-irmãs. Cada progênie continha 54 plantas (nove parcelas de seis plantas). O experimento seguiu o modelo látice 8 x 8 com nove repetições balanceadas. As análises foram conduzidas usando-se tanto este modelo quanto os modelos DBC e DIC. Com relação ao caráter altura, a estimativa da eficiência do DBC em relação ao DIC (Êb/i) foi de 48,6%; do látice em relação ao DBC (Êl/b), de 61%; e do látice em relação ao DIC (Êl/i), de 139%. A estimativa da correlação intraclasse entre plantas dentro das parcelas ( cˆ 2 ) foi de 9,4% para o DBC e zero para o látice. Para o caráter produção de massa verde, Êb/i, Êl/b e Êl/i foram de 14,3; 81,7; e 108%, respectivamente; e cˆ 2 , 16,9% para o DBC e 3,1% para o látice. Essas estimativas, associadas a uma estimativa de F de Snedecor altamente significativa dos dois caracteres, permitiram concluir que a capacidade de teste do DBC foi satisfatória para o caráter altura de plantas, mas insatisfatória para o caráter produção de massa verde

    Analysis of normal levels of free glycosaminoglycans in urine and plasma in adults

    Get PDF
    Plasma and urine glycosaminoglycans (GAGs) are long, linear sulfated polysaccharides that have been proposed as potential noninvasive biomarkers for several diseases. However, owing to the analytical complexity associated with the measurement of GAG concentration and disaccharide composition (the so-called GAGome), a reference study of the normal healthy GAGome is currently missing. Here, we prospectively enrolled 308 healthy adults and analyzed their free GAGomes in urine and plasma using a standardized ultra-high-performance liquid chromatography coupled with triple-quadrupole tandem mass spectrometry method together with comprehensive demographic and blood chemistry biomarker data. Of 25 blood chemistry biomarkers, we mainly observed weak correlations between the free GAGome and creatinine in urine and hemoglobin or erythrocyte counts in plasma. We found a higher free GAGome concentration - but not a more diverse composition - in males. Partitioned by gender, we also established reference intervals for all detectable free GAGome features in urine and plasma. Finally, we carried out a transference analysis in healthy individuals from two distinct geographical sites, including data from the Lifelines Cohort Study, which validated the reference intervals in urine. Our study is the first large-scale determination of normal free GAGomes reference intervals in plasma and urine and represents a critical resource for future physiology and biomarker research

    A Methodological Approach to Upscale Toward an Agroecology System in EU-LAFSs: The Case of the Parma Bio-District

    Get PDF
    The increasing interest in bio-districts is part of the debate on the capacity to integrate agri-food systems and territory in order to improve the quality of life in rural communities. Considering the goals of developing and promoting an innovative territorial rural development approach, the bio-district can become a process toward a more sustainable model represented by the agroecological agriculture system. The paper presents a case study of the Parma bio-district through the approach of a Localized Agri Food System (LAFS) to verify whether bio-districts can be a tool for scaling up towards agroecology. Stakeholder classification and analysis are conducted using an influence–interest matrix. We identified four groups of stakeholders in relation to their interests and power to influence the process. In the case of the Parma bio-district the role of local institutions in dialogue with consumers and producers’ associations is crucial for success. We conclude that bio-districts can be a tool for a scaling-up towards agroecology since they can facilitate a synergetic relation between organic and agroecological agriculture, spreading organic agriculture more widely around the local area. However, the involvement of a wide variety of dierent stakeholders means that governance is a key element in facilitating “cross fertilization” and preventing the process from becoming purely formulaic

    The IPD-IMGT/HLA Database

    Get PDF
    It is 24 years since the IPD-IMGT/HLA Database, http://www.ebi.ac.uk/ipd/imgt/hla/, was first released, providing the HLA community with a searchable repository of highly curated HLA sequences. The database now contains over 35 000 alleles of the human Major Histocompatibility Complex (MHC) named by the WHO Nomenclature Committee for Factors of the HLA System. This complex contains the most polymorphic genes in the human genome and is now considered hyperpolymorphic. The IPD-IMGT/HLA Database provides a stable and user-friendly repository for this information. Uptake of Next Generation Sequencing technology in recent years has driven an increase in the number of alleles and the length of sequences submitted. As the size of the database has grown the traditional methods of accessing and presenting this data have been challenged, in response, we have developed a suite of tools providing an enhanced user experience to our traditional web-based users while creating new programmatic access for our bioinformatics user base. This suite of tools is powered by the IPD-API, an Application Programming Interface (API), providing scalable and flexible access to the database. The IPD-API provides a stable platform for our future development allowing us to meet the future challenges of the HLA field and needs of the community

    Transport signatures of fragile glass dynamics in the melting of the two-dimensional vortex lattice

    Get PDF
    In a two-dimensional superconducting vortex lattice, the melting from the solid to the isotropic liquid can occur via an intermediate phase that retains orientational correlations. The effect of such correlations on transport and their interplay with the quenched disorder remain open questions. We perform magnetotransport measurements in a wide range of temperatures and magnetic fields on a weakly pinned two-dimensional vortex system in amorphous MoGe films. While at high fields, where quenched disorder dominates, we recover the typical strong-glass behavior of a vortex liquid, at low fields the resistivity shows a clear crossover to a fragile vortex glass. Our findings, supported by numerical simulations, suggest that this is a signature of heterogeneous dynamics that arises from the presence of orientational correlations
    • …
    corecore