On Self-Organized Criticality and Synchronization in Lattice Models of Coupled Dynamical Systems

Lattice models of coupled dynamical systems lead to a variety of complex behaviors. Between the individual motion of independent units and the collective behavior of members of a population evolving synchronously, there exist more complicated attractors. In some cases, these states are identified with self-organized critical phenomena. In other situations, with clusterization or phase-locking. The conditions leading to such different behaviors in models of integrate-and-fire oscillators and stick-slip processes are reviewed.Comment: 41 pages. Plain LaTeX. Style included in main file. To appear as an invited review in Int. J. Modern Physics B. Needs eps

Stability of Spatio-Temporal Structures in a Lattice Model of Pulse-Coupled Oscillators

We analyze the collective behavior of a lattice model of pulse-coupled oscillators. By studying the intrinsic dynamics of each member of the population and their mutual interactions we observe the emergence of either spatio-temporal structures or synchronized regimes. We perform a linear stability analysis of these structures.Comment: 15 pages, 2 PostScript available upon request at [email protected], Accepted in Physica

Tratamiento del Síndrome del Túnel Carpiano con la Técnica del Retinaculotomo de PAINE

Los autores han realizado un estudio con 36 casos intervenidos quirúrgicamente en el Servicio de Neurocirugía del Hospital General de Especialidades "Virgen de las Nieves" de Granada, tanto a corto como a largo plazo, empleando la técnica quirúrgica de PAINE, basada en el instrumento por él diseñado, el retinaculotomo. Realizan un estudio de los resultados obtenidos, siendo totalmente satisfactorios en el 74% de los casos. Finalmente exponen las ventajas de esta técnica quirúrgica, así como, la práctica ausencia de complicaciones.36 Patients with Carpal Tunnel Syndrome are colected. All of them -were operated on by PAINE's Technique and Procedur e (Retinaculotome). The authors made a study of the results obtained, 74% of good results. Finally, they explain the advantage s of this surgical procedure, as well as, absence of complications

Utility aspects of sugarcane bagasse as a feedstock for bioethanol production: leading role of steam explosion as a pretreatment technique

Lignocellulosic biomass is a powerful approach to produce sustainable biofuels and the further achievement of the goal of biomass conversion into a second-generation clean energy that can cope with the depletion of fossil reserves and rising energy requirements. In the conversion process, a pretreatment is essential to overcome the recalcitrance of the lignocellulosic biomass; accelerate its disintegration into cellulose, hemicellulose, and lignin; and, in turn, obtain an optimal yield of fermentable sugars in the enzymatic hydrolysis. In addition to this, it should be industrially scalable and capable of enhancing fuel properties and feedstock processability. Here, steam explosion technology has stood out due to its results and advantages, such as wide applicability, high efficiency in the short term, or lack of contamination despite its conventionality. This gentle and fast pretreatment incorporates high temperature autohydrolysis and structural alteration by explosive decompression. The steam explosion method has been one of the most effectual, especially for the hydrolysis of cellulose from agricultural wastes due to the lower quantity of acetyl groups in the composition of hemicellulose. In this aspect, sugarcane bagasse is a promising feedstock for bioethanol production due to its high cellulosic content and elevated availability. The objective of this review has been to compile the latest information on steam explosion pretreatment, stages, equipment, variables involved, by-products generated, as well as the advantages and disadvantages of the technique. At the same time, its feasibility and viability using sugarcane bagasse as feedstock has been discussed. Finally, the effectiveness of the technique with different feedstocks has been evaluated.Xunta de Galicia | Ref. ED431F 2020/12Agencia Estatal de Investigación | Ref. RYC-2017-22891Xunta de Galicia | Ref. ED481B-2019/09

Single Cord Blood Combined with HLA-Mismatched Third Party Donor Cells: Comparable Results to Matched Unrelated Donor Transplantation in High-Risk Patients with Hematologic Disorders

AbstractMatched unrelated donor (MUD) transplantation is the first alternative in the absence of a matched sibling donor. For patients without a suitable adult donor, we have adopted the dual stem cell transplantation protocol consisting of cord blood (CB) in combination with CD34+ cells from a third party HLA-mismatched donor. We analyzed the outcomes of patients undergoing both procedures in a single center. Starting in 2004, a total of 20 patients with high-risk disease underwent 22 dual transplants and 25 patients underwent myeloablative MUD transplantation. The 30-day cumulative incidence of neutrophil engraftment was similar in both groups (91% and 95%), with a median time to engraftment of 14 and 16 days, respectively. Grade II-IV acute graft-versus-host disease was more frequent in the MUD group (40% versus 5%). Except for a tendency toward a higher incidence of viral hemorrhagic cystitis in the dual transplantation group, posttransplantation infectious events were comparable in the 2 groups. The 3-year cumulative incidence rates of relapse (41% versus 44%) and nonrelapse mortality (30% versus 25%) were similar in the MUD and dual transplantation cohorts. Estimated 3-year overall survival and disease-free survival were 47% and 41%, respectively, with no survival advantage for either group. In our experience, dual transplantation offers survival rates comparable to those from myeloablative MUD transplantation with similar nonrelapse mortality rates

Rotura del tendón distal del bíceps braquial

Objetivo: presentar nuestra experiencia en el tratamiento de las roturas del tendón del bíceps braquial en trabajadores manuales. Material y métodos: Hemos intervenido a 9 pacientes con una edad media de 47 años, realizando en 8 ocasiones una reinserción transósea del tendón en la tuberosidad bicipital del radio por medio de una doble vía de abordaje. El seguimiento medio ha sido de 13 meses. Resultados: fueron excelentes, recuperando en todos los casos la fuerza muscular previa y una movilidad media final completa para la flexión y extensión, 85º de supinación y 86º de pronación. Todos se han reincorporado a su puesto de trabajo en un período entre los 3 y 4 meses. Conclusiones: Esta técnica se ha mostrado muy eficaz en el tratamiento de este tipo de patología, recomendándose siempre la cirugía en pacientes activos.Objective: to present our experience in the treatment of ruptures of the distal biceps braquialis tendon in hand workers. Methods: 9 patients, middle age 47, went under surgery, 8 of them with a transoseus reinsertion of the tendon in the bicipital tuberosity of the radius with a double surgical approach. The average follow-up was 13 months. Results: excellent results were achieved in all of the 9 patients, recovering previous muscle strength, with full range of flexion-extension, 85º of supination and 86º of pronation. All 9 patients return to work in a period of 3 to 4 months. Conclusion: this technique is effective in the treatment of this injury, and it is recommended in active patients

On Synchronization in a Lattice Model of Pulse-Coupled Oscillators

We analyze the collective behavior of a lattice model of pulse-coupled oscillators. By means of computer simulations we find the relation between the intrinsic dynamics of each member of the population and their mutual interaction that ensures, in a general context, the existence of a fully synchronized regime. This condition turns out to be the same than the obtained for the globally coupled population. When the condition is not completely satisfied we find different spatial structures. This also gives some hints about self-organized criticality.Comment: 4 pages, RevTex, 1 PostScript available upon request, To appear in Phys. Rev. Let

Symmetries and Fixed Point Stability of Stochastic Differential Equations Modeling Self-Organized Criticality

A stochastic nonlinear partial differential equation is built for two different models exhibiting self-organized criticality, the Bak, Tang, and Wiesenfeld (BTW) sandpile model and the Zhang's model. The dynamic renormalization group (DRG) enables to compute the critical exponents. However, the nontrivial stable fixed point of the DRG transformation is unreachable for the original parameters of the models. We introduce an alternative regularization of the step function involved in the threshold condition, which breaks the symmetry of the BTW model. Although the symmetry properties of the two models are different, it is shown that they both belong to the same universality class. In this case the DRG procedure leads to a symmetric behavior for both models, restoring the broken symmetry, and makes accessible the nontrivial fixed point. This technique could also be applied to other problems with threshold dynamics.Comment: 19 pages, RevTex, includes 6 PostScript figures, Phys. Rev. E (March 97?