Time scale competition leading to fragmentation and recombination transitions in the coevolution of network and states

We study the co-evolution of network structure and node states in a model of multiple state interacting agents. The system displays two transitions, network recombination and fragmentation, governed by time scales that emerge from the dynamics. The recombination transition separates a frozen configuration, composed by disconnected network components whose agents share the same state, from an active configuration, with a fraction of links that are continuously being rewired. The nature of this transition is explained analytically as the maximum of a characteristic time. The fragmentation transition, that appears between two absorbing frozen phases, is an anomalous order-disorder transition, governed by a crossover between the time scales that control the structure and state dynamics.Comment: 5 pages, 5 figures, figures 2 and 4 changed, tile changed, to be published in PR

VLBA determination of the distance to nearby star-forming regions I. The distance to T Tauri with 0.4% accuracy

In this article, we present the results of a series of twelve 3.6-cm radio continuum observations of T Tau Sb, one of the companions of the famous young stellar object T Tauri. The data were collected roughly every two months between September 2003 and July 2005 with the Very Long Baseline Array (VLBA). Thanks to the remarkably accurate astrometry delivered by the VLBA, the absolute position of T Tau Sb could be measured with a precision typically better than about 100 micro-arcseconds at each of the twelve observed epochs. The trajectory of T Tau Sb on the plane of the sky could, therefore, be traced very precisely, and modeled as the superposition of the trigonometric parallax of the source and an accelerated proper motion. The best fit yields a distance to T Tau Sb of 147.6 +/- 0.6 pc. The observed positions of T Tau Sb are in good agreement with recent infrared measurements, but seem to favor a somewhat longer orbital period than that recently reported by Duchene et al. (2006) for the T Tau Sa/T Tau Sb system.Comment: 24 pages, 3 pages, AASTEX format, accepted for publication in Ap

Phylogenetic analyses and toxigenic profiles of Fusarium equiseti and Fusarium acuminatum isolated from cereals from Southern Europe

Fusarium equiseti and Fusarium acuminatum are toxigenic species that contaminate cereal crops from diverse climatic regions. They are common in Spanish cereals. The information available on their phylogenetics and toxigenic profiles is, however, insufficient to assist risk evaluation. In this work, phylogenetic analyses were performed using partial sequences of the translation elongation factor gene (EF-1a) of F. equiseti and F. acuminatum strains isolated from barley and wheat from Spain and other countries. The Northern and Southern European F. equiseti strains largely separated into two phylogenetically distinct clusters. This suggests the existence of two distinct populations within this species, explaining its presence in these regions of markedly different climate. Production of type A and B trichothecenes by the Spanish strains, examined in wheat cultures using a multitoxin analytical method, indicated that F. equiseti could produce deoxynivalenol and nivalenol and other trichothecenes, at concentrations that might represent a significant risk of toxin contamination for Southern European cereals. F. acuminatum showed low intraspecific genetic variability and 58% of the strains could produce deoxynivalenol at low level. Neither species was found to produce T-2 or HT-2 toxins. The present results provide important phylogenetic and toxigenic information essential for the accurate prediction of toxigenic risk

Dynamic analysis using finite elements to calculate the critical wear section of the contact wire in suburban railway overhead conductor rails

The purpose of this study is to determine the critical wear levels of the contact wire of the catenary on metropolitan lines. The study has focussed on the zones of contact wire where localised wear is produced, normally associated with the appearance of electric arcs. To this end, a finite element model has been developed to study the dynamics of pantograph-catenary interaction. The model includes a zone of localised wear and a singularity in the contact wire in order to simulate the worst case scenario from the point of view of stresses. In order to consider the different stages in the wire wear process, different depths and widths of the localised wear zone were defined. The results of the dynamic simulations performed for each stage of wear let the area of the minimum resistant section of the contact wire be determined for which stresses are greater than the allowable stress. The maximum tensile stress reached in the contact wire shows a clear sensitivity to the size of the local wear zone, defined by its width and depth. In this way, if the wear measurements taken with an overhead line recording vehicle are analysed, it will be possible to calculate the potential breakage risk of the wire. A strong dependence of the tensile forces of the contact wire has also been observed. These results will allow priorities to be set for replacing the most critical sections of wire, thereby making maintenance much more efficient. The results obtained show that the wire replacement criteria currently borne in mind have turned out to be appropriate, although in some wear scenarios these criteria could be adjusted even more, and so prolong the life cycle of the contact wire

Steel heat treating: Mathematical modelling and numerical simulation of a problem arising in the automotive industry

We describe a mathematical model for the industrial heating and cooling processes of a steel workpiece representing the steering rack of an automobile. The goal of steel heat treating is to provide a hardened surface on critical parts of the workpiece while keeping the rest soft and ductile in order to reduce fatigue. The high hardness is due to the phase transformation of steel accompanying the rapid cooling. This work takes into account both heating-cooling stage and viscoplastic model. Once the general mathematical formulation is derived, we can perform some numerical simulations

Ingesta dietética e índices antropométricos en estudiantes de medicina mexicanos, estratificados por historia familiar de Diabetes Tipo 2

Introduction: Our aim was to evaluate the dietary intake and anthropometric indices in medical students with positive family history of type 2 diabetes (FH-T2D)(+) and without FH-T2D(-).Material and methods: 144 students were analyzed in this cross-sectional, observational study, conducted during the 2017-2018 school year using interviews and 7-day food diary. The participants were characterized anthropometrically. Waist-to-hip ratio (WHR) and waist-to-height ratio (WHtR), corrected mid-arm muscle area (MAMA), fat arm index (FAI), and tricipital skinfold (TSF) were calculated. Results: we found that 79.2% (95%CI: 72.5- 85.8) had FH-T2D. BMI was significantly higher in the participants with FH-T2D than without (23.7±3.8 v 25.0±3.7, respectively, p<0.05). No significant differences were determined in the indices based on central fat distribution (WHtR and WHR), peripheral distribution (FAI and TSF), or muscle mass (MAMA), when stratified by FH-T2D. Regarding dietary intake, when comparing participants with and without FH-T2D, respectively, we observed low/none legume consumption [30% (95%CI: 21.4-38.2) vs 23% (95%CI: 8.2-38.5)], diets high in proteins [38.6% (95%CI: 29.7-47.5) vs 46.7% (95%CI: 28.8-64.5)], low in carbohydrates [84.2% (95%CI: 77.5-90.9) vs 83.3% (95%CI: 70.0-96.7)], and insufficient energy intake [64% (95%CI: 55.2-72.8) vs 56.7% (95%CI: 38.9-74.4)], where the alterations in the dietary pattern were more detrimental for the FH-T2D(+) group. Lastly, the participants with FH-T2D consumed mainly late in the day [60% (95%CI: 50.6-68.6) vs 54% (95%CI: 35.5-71.2)].Conclusions: Even though there were minimal significant differences with the consumption by food categories, those students with FH-T2D presented with a poor, little varied and unbalanced dietary pattern with energy consumption mainly at night. These factors, if prolonged, could increase the risk of developing type 2 diabetes.Introducción: Nuestro objetivo fue evaluar la ingesta dietética y los índices antropométricos en estudiantes de medicina con historia familiar positiva de diabetes tipo 2 (FH-T2D)(+) y sin antecedentes familiares FH-T2D(-).Material y métodos: 144 estudiantes fueron analizados en este estudio transversal y observacional realizado durante el año escolar 2017-2018 mediante entrevistas y un diario de alimentos de 7 días. Los participantes se caracterizaron antropométricamente. Se calculó el ínidce cintura-cadera (WHR) y el índice cintura-altura (WHtR), el área muscular corregida de la mitad del brazo (MAMA), el índice de grasa del brazo (FAI) así como el pliegue cutáneo tricipital (TSF).Resultados:El 79,2% (95%CI: 72,5- 85,8) tenían FH-T2D. El IMC fue significativamente mayor en los participantes con FH-T2D que en aquellos sin FH-T2D (23,7 ± 3,8 v 25,0 ± 3,7, respectivamente, p <0,05). No se determinaron diferencias significativas en los índices basados en la distribución de grasa central (WHtR y WHR), la distribución periférica (FAI y TSF) o la masa muscular (MAMA), cuando se estratificó por FH-T2D. Al comparar la ingesta dietética de participantes con y sin FH-T2D, respectivamente, observamos un consumo bajo / ninguno de leguminosas [30% (95%CI: 21,4-38,2) frente a 23% (95%CI: 8,2-38,5)], dietas altas en proteínas [38,6% (95%CI: 29,7-47,5) frente a 46,7% (95%CI: 28,8-64,5)], bajas en carbohidratos [84,2% (95%CI: 77,5-90,9) frente a 83,3% (95%CI: 70,0-96,7)], y la ingesta de energía insuficiente [64% (95%CI: 55,2-72,8) frente a 56,7% (95%CI: 38,9-74,4)], donde las alteraciones en el patrón de la dieta fueron más perjudiciales para el grupo FH-T2D(+). Los participantes con FH-T2D consumieron al final del día [60% (95%CI: 50,6-68,6) frente a 54% (95%CI: 35,5-71,2)].Conclusiones: Aunque hubo diferencias mínimas significativas con el consumo por categorías de alimentos, aquellos estudiantes con FH-T2D presentaron un patrón dietético deficiente, poco variado y desequilibrado con un consumo de energía principalmente por la noche. Estos factores, si se prolongan, podrían aumentar el riesgo de desarrollar diabetes tipo 2

Synchronous motion of two vertically excited planar elastic pendula

The dynamics of two planar elastic pendula mounted on the horizontally excited platform have been studied. We give evidence that the pendula can exhibit synchronous oscillatory and rotation motion and show that stable in-phase and anti-phase synchronous states always co-exist. The complete bifurcational scenario leading from synchronous to asynchronous motion is shown. We argue that our results are robust as they exist in the wide range of the system parameters.Comment: Submitte

Characterization of mussel H2A.Z.2: a new H2A.Z variant preferentially expressed in germinal tissues from Mytilus

Histones are the fundamental constituents of the eukaryotic chromatin, facilitating the physical organization of DNA in chromosomes and participating in the regulation of its metabolism. The H2A family displays the largest number of variants among core histones, including the renowned H2A.X, macroH2A, H2A.B (Bbd) and H2A.Z. This latter variant is especially interesting due to its regulatory role and its differentiation into two functionally divergent variants (H2A.Z.1 and H2A.Z.2), further specializing the structure and function of vertebrate chromatin. In the present work we describe, for the first time, the presence of a second H2A.Z variant (H2A.Z.2) in the genome of a non-vertebrate animal, the mussel Mytilus. The molecular and evolutionary characterization of mussel H2A.Z.1 and H2A.Z.2 histones is consistent with their functional specialization, supported on sequence divergence at promoter and coding regions as well as on varying gene expression patterns. More precisely, the expression of H2A.Z.2 transcripts in gonadal tissue and its potential upregulation in response to genotoxic stress might be mirroring the specialization of this variant in DNA repair. Overall, the findings presented in this work complement recent reports describing the widespread presence of other histone variants across eukaryotes, supporting an ancestral origin and conserved role for histone variants in chromatin