Excitations in one-dimensional lattices with traps: exact results and simulations

We study motion and capture of incoherent excitons in one-dimensional lattices with randomly placed, perfectly absorbing traps. Large-scale numerical simulations of both the master equation and the random walk version of the problem disagree with the result for the survival fraction obtained long ago by Movaghar et al. [J. Stat. Phys. 27 (1982) 473]. We carry out exact calculations for this problem and find that the disagreement can be traced back to rare-event contributions to the analytical result which cannot be seen in simulations. We conclude that for practical purposes, Le., for averages taken over any finite number of realizations, the only asymptotics observable is the one we have found in our simulations.Work at Madrid and Leganes is supported by CICYT under project MAT95-0325. Work at Cantabria is supported by OGICYT under project PB93-0054-C02-02.Publicad

Learning from failure propagation in steel truss bridges

Although truss-type bridge collapses usually have catastrophic consequences, their analysis present opportunities for improving different aspects in the field of bridge engineering, such as structural assessment, structural health monitoring, maintenance and conservation or even design strategies. As the world experiences more extreme events, efforts have been made to design more resilient bridges that can withstand local failures. Forensic techniques have contributed to understanding the causes and risk factors of bridge failures, and the creation of collapse databases has provided valuable insights for preventing such failures. However, these databases often focus on the hazards and do not provide information on initial damage and how it propagates, which is essential for improving the progressive collapse resistance of truss-type bridges. The main novelty of this paper is to present a methodology to identify triggering events leading to progressive collapse on truss-type bridges. It is the first time that a methodology includes a novel database which collects detailed information on initial damages and its propagation, as well as the consequences of the collapse. The methodology was implemented by collecting information from 25 case studies present in the literature. Results have allowed to identify most frequent initial constituted damages states or failures (ICDS) leading progressive collapse. In terms of consequences, results were thoroughly analysed and compared with predictions from different casualty models. The findings showed that the proposed methodology serves as an effective tool for identifying the triggering events of progressive collapse in truss-type bridges.Agencia Estatal de Investigación | Ref. PID2021-124236OBAgencia Estatal de Investigación | Ref. FJC2020–046370-IUniversidade de Vigo/CISU

Assessment of hormonal parameters in long-term karate Practitioners

Introduction: Karate is a Japanese martial art which is widely practiced in the Western world as a form of self-defense, as well as a discipline to achieve physical and mental balance.However, little is known with respect to its specific psychobiological effects, particularly in relation to the influence that karate may exert on the endocrine system. Thus, in the present study we analyzed the effects of regular karate practice on several hormonal parameters. Methods: 27 healthy volunteer subjects participated in the study, of whom 15 were allocated to the experimental group, and 12 were assigned to the control group. Experimental subjects were karate players with a minimum of 3 years of practice in this discipline. Blood samples for the quantification of hormonal parameters (TSH, T3, T4, PTH, ACTH, cortisol, and DHEA) were taken in both groups. To compare the means of the control and experimental group, a t-test for independent groups was performed in each dependent variable. Results: Significant differences between the experimental and control group were found in T3, T4, and cortisol, with karate players showing lower blood levels of these hormones than control. Conclusions: These findings reveal that long-term karate practice is associated to a significant endocrine modulation, which suggests interesting psychobiological implications, and lends itself to potential clinical considerations. Further research is needed to properly assess the scope of the peculiar hormonal profile displayed by advanced karate practitioners.Universidad de Málaga, Campus de Excelencia Internacional Andalucía Tec

Immune modulation after long-term karate practice

Introduction: Karate is a Japanese martial arts system which traces its roots back to China, and is nowadays widely popular both as a method of self-defense, as well as a discipline with potential physical and psychological benefits. However, karate has been scarcely investigated from a psychobiological perspective, and its effects on the immune system remain virtually unknown. Therefore, we designed the present study with the aim of analyzing the effects of several years of regular karate practice on different immune parameters. Methods: 27 healthy volunteer subjects participated in the study, 15 being allocated to the experimental group, and 12 to the control group. Experimental subjects were all karate players who had practiced this martial art for a minimum of three years. Blood samples for the quantification of immune parameters (leukocytes, neutrophils, monocytes, eosinophils, basophils, lymphocytes, IgG, IgA, IgM, IgE) were taken in both groups. As statistical analysis, a t-test for independent groups was performed in each dependent variable. Results: Compared to the control group, karate practitioners exhibited a significantly higher number of leukocytes, monocytes, and lymphocytes, as well as greater serum concentrations of IgG and IgM. Conclusions: Our findings show that long-term karate practice is related to a broad modulation of immune parameters, including leukocytes counts as well as immunoglobulin concentrations. This peculiar immunomodulatory profile, apart from its psychobiological relevance, may have noteworthy clinical implications. Further investigation would be necessary to fully elucidate the influence that long-term karate training can exert on the immune system.Universidad de Málaga, Campus de Excelencia Internacional Andalucía Tec

Inyecciones de conglomerados en el Triásico de Pálmaces de Jadraque (Guadalajara)

Conglomerate dykes have been observed in Buntsandstenin deposits surrounding of Palmaces de Jadraque dam (Spanish Central System southeast border). Deformed sediments by liquefaction correspond to fluvial systems of mixed load rivers of gravels and sands. Conglomerate dykes have a true tectonic control. These structures have a mean trend NW-SE and another perpendicular one, are less developed. These trends are compatible with extensional process proposed by different authors for this time. Due to tectonic control as well as the associated tectonic extensional process, liquefactions trigger mechanism could be seismic

Texture-induced enhancement of the magnetocaloric response in melt-spun DyNi2 ribbons

"The magnetocaloric properties of melt-spun ribbons of the Laves phase DyNi2 have been investigated. The as-quenched ribbons crystallize in a single-phase MgCu2-type crystal structure (C15; space group Fd (3) over barm) exhibiting a saturation magnetization and Curie temperature of M-S = 157 +/- 2 A m(2) kg(-1) and T-C = 21.5 +/- 1 K, respectively. For a magnetic field change of 2 T, ribbons show a maximum value of the isothermal magnetic entropy change vertical bar Delta S-M(peak)vertical bar = 13.5 J kg(-1) K-1, and a refrigerant capacity RC = 209 J kg(-1). Both values are superior to those found for bulk polycrystalline DyNi2 alloys (25% and 49%, respectively). In particular, the RC is comparable or larger than that reported for other potential magnetic refrigerants operating at low temperatures, making DyNi2 ribbons promising materials for use in low-temperature magnetic refrigeration applications.

Texture-induced enhancement of the magnetocaloric response in melt-spun DyNi2 ribbons

"The magnetocaloric properties of melt-spun ribbons of the Laves phase DyNi2 have been investigated. The as-quenched ribbons crystallize in a single-phase MgCu2-type crystal structure (C15; space group Fd (3) over barm) exhibiting a saturation magnetization and Curie temperature of M-S = 157 +/- 2 A m(2) kg(-1) and T-C = 21.5 +/- 1 K, respectively. For a magnetic field change of 2 T, ribbons show a maximum value of the isothermal magnetic entropy change vertical bar Delta S-M(peak)vertical bar = 13.5 J kg(-1) K-1, and a refrigerant capacity RC = 209 J kg(-1). Both values are superior to those found for bulk polycrystalline DyNi2 alloys (25% and 49%, respectively). In particular, the RC is comparable or larger than that reported for other potential magnetic refrigerants operating at low temperatures, making DyNi2 ribbons promising materials for use in low-temperature magnetic refrigeration applications.

Hallazgos electroclínicos y evolutivos en pacientes con alteración en el gen KCNQ2. Serie de 6 casos

Introducción: Los trastornos relacionados con las alteraciones en el gen KCNQ2 incluyen un amplio rango de fenotipos epilépticos de inicio en la edad neonatal, desde epilepsia neonatal familiar benigna (ENFB) hasta casos de encefalopatía epiléptica neonatal (EEN) que en algunas ocasiones presentan características similares al síndrome de Ohtahara con un trazado de tipo paroxismo-supresión aunque con mejor control de crisis e infrecuente evolución a síndrome de West. Pacientes y métodos: Estudio descriptivo y retrospectivo de una serie de 6 casos con crisis de inicio en la etapa neonatal y presencia de mutación en el gen KCNQ2. Resultados: las crisis se iniciaron en todos los casos en la primera semana de vida, siendo las más frecuentes las crisis tónicas, seguidas de las crisis sutiles y las crisis hemiclónicas. Un paciente asoció además mioclonias y trastornos del movimiento. En el EEG del período neonatal destaca la presencia de actividad paroxística focal en 4 pacientes y trazado de brote-supresión en 2 casos. En las pruebas de neuroimagen, en 5 de los pacientes, se encontraron anomalías de diverso tipo (atrofia cortical, asimetría en astas temporales, alteración de la sustancia blanca periventricular y polimicrogiria). En la evolución posterior, 5 casos presentaron retraso psicomotor en mayor o menor grado, de los cuales, 3 desarrollaron epilepsia focal sintomática, un caso Síndrome de West y otro, encefalopatía epiléptica. Por último, un paciente fue diagnosticado de ENFB con buena evolución clínica y electroencefalográfica. Conclusión: Existe un amplio espectro en el tipo de epilepsia asociada a las alteraciones del gen KCNQ2 con características electroclínicas y evolutivas muy diversas, destacando en nuestra serie los casos con epilepsia focal sintomática y encefalopatía epiléptica (uno de ellos con S. West). Sólo un paciente tuvo una forma benigna de epilepsia (ENFB).Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Seasonal variability of gelatinous zooplankton during an anomalously warm year at Cabo Pulmo national park, Mexico

The seasonal variability of gelatinous zooplankton (siphonophores, medusae, and thaliaceans) abundance was investigated at Cabo Pulmo National Park (CPNP) from weekly zooplankton samples collected throughout 2014. The Gulf of California had prolonged warming during 2009-2019, with 2014 as the anomalously warm year preceding El Niño 2015-2016 compared to the 2003-2020 SST time series. Gelatinous zooplankton accounted <1% of the entire zooplankton community abundance at CPNP during 2014, suggesting a low influence of predation pressure upon their zooplanktonic and micronekton preys. Siphonophores (57%), thaliaceans (42%), and medusae (1%) were present throughout the year. The abundance of gelatinous zooplankton had a significant negative association with sea surface temperature and a positive association with sea surface chlorophyll-a concentration and velocity and direction of the wind, increasing their abundance during October after the hurricane season. The gelatinous zooplankton species assemblage at the coastal CPNP was similar but less abundant than the gelatinous zooplankton species assemblage observed in the oceanic region of the southern Gulf of California during summer 2014. Tropical species Diphyes dispar, Abylopsis tetragona, Chelophyes contorta, and Thalia spp. numerically dominated the gelatinous zooplankton community associated with a regional heatwave period recorded during 2014. A high proportion of tropical zooplankton indicates that mesotrophic conditions sustain the current high biomass and diversity of nektonic and benthonic planktophagous fauna inhabiting CPNP. However, prolonged warming events might decrease zooplankton biomass in the southern region of the Gulf of California in the future.Fil: Silveyra Bustamante, Angel Antonio. Instituto Politécnico Nacional; MéxicoFil: Gómez Gutiérrez, Jaime. Instituto Politécnico Nacional; MéxicoFil: González Rodríguez, Eduardo. Consejo Nacional de Ciencia y Tecnologia de Mexico. Centro de Investigacion Cientifica y de Educacion Superior de Ensenada Baja California.; MéxicoFil: Sánchez, Carlos. Universidad Autónoma de Baja California Sur; MéxicoFil: Schiariti, Agustin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina. Instituto Nacional de Investigaciones y Desarrollo Pesquero; ArgentinaFil: Mendoza Becerril, María A.. Consejo Nacional de Ciencia y Tecnología; Méxic

Enhanced refrigerant capacity in two-phase nanocrystalline/amorphous NdPrFe17 melt-spun ribbons

"he magnetocaloric properties of NdPrFe17 melt-spun ribbons composed of nanocrystallites surrounded by an intergranular amorphous phase have been studied. The nanocomposite shows two successive second-order magnetic phase transitions (303 and 332 K), thus giving rise to a remarkable broadening (approximate to 84 K) of the full-width at the half-maximum of the magnetic entropy change curve, Delta S-M(T), with a consequent enhancement of the refrigerant capacity RC. For a magnetic field change of 2 T, vertical bar Delta S-M(peak)vertical bar = 2.1 J kg(-1) K-1 and RC = 175 J kg(-1). Therefore, the reversible magnetocaloric response together with the one-step preparation process makes these nanostructured Fe-rich alloy ribbons particularly attractive for room temperature magnetic refrigeration.