Simulations of viscous shape relaxation in shuffled foam clusters

We simulate the shape relaxation of foam clusters and compare them with the time exponential expected for Newtonian fluid. Using two-dimensional Potts Model simulations, we artificially create holes in a foam cluster and shuffle it by applying shear strain cycles. We reproduce the experimentally observed time exponential relaxation of cavity shapes in the foam as a function of the number of strain steps. The cavity rounding up results from local rearrangement of bubbles, due to the conjunction of both a large applied strain and local bubble wall fluctuations

Selection of reference genes for quantitative real-time PCR expression studies of microdissected reproductive tissues in apomictic and sexual Boechera

Abstract Background Apomixis, a natural form of asexual seed production in plants, is considered to have great biotechnological potential for agriculture. It has been hypothesised that de-regulation of the sexual developmental pathway could trigger apomictic reproduction. The genus Boechera represents an interesting model system for understanding apomixis, having both sexual and apomictic genotypes at the diploid level. Quantitative qRT-PCR is the most extensively used method for validating genome-wide gene expression analyses, but in order to obtain reliable results, suitable reference genes are necessary. In this work we have evaluated six potential reference genes isolated from a 454 (FLX) derived cDNA library of Boechera. RNA from live microdissected ovules and anthers at different developmental stages, as well as vegetative tissues of apomictic and sexual Boechera, were used to validate the candidates. Results Based on homologies with Arabidopsis, six genes were selected from a 454 cDNA library of Boechera: RPS18 (Ribosomal sub protein 18), Efalpha1 (Elongation factor 1 alpha), ACT 2 (Actin2), UBQ (polyubiquitin), PEX4 (Peroxisomal ubiquitin conjugating enzyme) and At1g09770.1 (Arabidopsis thaliana cell division cycle 5). Total RNA was extracted from 17 different tissues, qRT-PCRs were performed, and raw Ct values were analyzed for primer efficiencies and gene ratios. The geNorm and normFinder applications were used for selecting the most stable genes among all tissues and specific tissue groups (ovule, anthers and vegetative tissues) in both apomictic and sexual plants separately. Our results show that BoechRPS18, BoechEfα1, BoechACT2 and BoechUBQ were the most stable genes. Based on geNorm, the combinations of BoechRPS18 and BoechEfα1 or BoechUBQ and BoechEfα1 were the most stable in the apomictic plant, while BoechRPS18 and BoechACT2 or BoechUBQ and BoechACT2 performed best in the sexual plant. When subgroups of tissue samples were analyzed, different optimal combinations were identified in sexual ovules (BoechUBQ and BoechEfα1), in anthers from both reproductive systems (BoechACT2 and BoechEfα1), in apomictic vegetative tissues (BoechEfα1 and BoechACT2) and sexual vegetative tissues (BoechRPS18 and BoechEfα1). NormFinder ranked BoechACT2 as the most stable in the apomictic plant, while BoechRPS18 was the best in the sexual plant. The subgroups analysis identified the best gene for both apomictic and sexual ovules (BoechRPS18), for anthers from both reproductive system (BoechEfα1) and for apomictic and vegetative tissues (BoechACT2 and BoechRPS18 respectively) Conclusions From a total of six tested genes, BoechRPS18, BoechEfα1, BoechACT2 and BoechUBQ showed the best stability values. We furthermore provide detailed information for the accurate normalization of specific tissue gene expression analyses of apomictic and sexual Boechera.</p

Modeling the ecology and evolution of biodiversity: Biogeographical cradles, museums, and graves

Individual processes shaping geographical patterns of biodiversity are increasingly understood, but their complex interactions on broad spatial and temporal scales remain beyond the reach of analytical models and traditional experiments. To meet this challenge, we built a spatially explicit, mechanistic simulation model implementing adaptation, range shifts, fragmentation, speciation, dispersal, competition, and extinction, driven by modeled climates of the past 800,000 years in South America. Experimental topographic smoothing confirmed the impact of climate heterogeneity on diversification. The simulations identified regions and episodes of speciation (cradles), persistence (museums), and extinction (graves). Although the simulations had no target pattern and were not parameterized with empirical data, emerging richness maps closely resembled contemporary maps for major taxa, confirming powerful roles for evolution and diversification driven by topography and climate

Structural dynamic updating using a global optimization methodology

In this article, we present the application of a global optimization technique, in particular the GlobalSearch command from MatLab®, in the updating of structural dynamic models. For comparative purposes, we evaluate the efficiency of the global method relatively to the local search method previously used in the Finite Element Model Updating program. The Finite Element Model Updating programs are designed with the primary purpose of validating and optimizing structural numerical models. The first step for structural optimization process is to idealize the desired behavior of the dynamic model to develop, or collect experimental data of a physical model considered as the reference model. The process begins with the construction, on a finite element program, of a numerical model with initial physical parameters, preferably close to the reference model parameters. The numerical model is then submitted, through a Finite Element Model Updating program, to a successive parametric updating until improving its dynamic behavior described by their natural frequencies, mode shapes and damping properties, be similar to the dynamic behavior of the reference model. The Sequential Quadratic Programming algorithm was already used in the optimization of the Finite Element Model Updating program, and the obtained solutions showed that it can’t achieve the global optimal value of the objective function. This kind of methods, used for nonlinear constrained optimization problems, have, generally, difficulties to achieve the global optimum, since they are local optimization methods.Centre for Mechanical and Materials Technologies (CT2M) and Algoritmi R&D Centreinfo:eu-repo/semantics/publishedVersio

Magnetism in nanometer-thick magnetite

The oldest known magnetic material, magnetite, is of current interest for use in spintronics as a thin film. An open question is how thin can magnetite films be and still retain the robust ferrimagnetism required for many applications. We have grown one-nanometer-thick magnetite crystals and characterized them in situ by electron and photoelectron microscopies including selected-area x-ray circular dichroism. Well-defined magnetic patterns are observed in individual nano-crystals up to at least 520 K, establishing the retention of ferrimagnetism in magnetite two-unit-cells thick.Comment: 5 pages, 4 figure

El efecto de las redes organizativas sobre los festivales en pequeñas ciudades

Los festivales son un tipo de evento que ofrece verdaderas oportunidades para la activación urbana en ciudades de pequeño o mediano tamaño. Sin embargo, estas ciudades explotan de manera muy diversa este tipo de oportunidades. Las redes involucradas en estos eventos culturales determinan en cierta medida sus beneficios potenciales y también sus restricciones. Hemos analizado tres festivales que se llevan a cabo en destinos turísticos españoles de pequeño tamaño. Nuestros resultados confirman la existencia de diferentes mecanismos de gobernabilidad de las redes involucradas en los festivales. Las implicaciones de este trabajo pueden ser útiles, tanto para el diseño de políticas como para la organización individual de los eventos.Events such as festivals offer considerable opportunities for urban activation in medium or small cities. However, cities significantly vary in the degree they exploit these opportunities. This paper analyzes this relevant question adopting a network perspective. We argue that networks of people and organizations involved in a cultural event determine to some extent its potential benefits and restraints. We have illustrated our argumentation though three festivals held in minor urban touristic destinations in Spain. Findings confirm the existence of different modes of network governance in festivals. Implications may be useful for both policy makers and individual organizations

Gastroesophageal reflux disease in surgical versus clinical literature: clinicians do not read surgical journals

BACKGROUND: Several diseases may be treated either medically or surgically; however, clinical and surgical therapies are often not treated as different options for the same patient but rather as different medical philosophies. AIM: To assess whether the main surgical and medical journals make references to their counterparts, with gastroesophageal reflux as a model of clinical/surgical disease. METHOD: It was reviewed the leading medical journals in order to verify if surgeons and clinicians make references to their counterparts on their work using gastroesophageal reflux disease as a model of a clinical/surgical disease. It was reviewed the five top-ranked journals in the field of gastroenterology, general surgery and general medicine and a neutral journal. The issues of the year 2008 of the selected journals were searched for papers dealing with gastroesophageal reflux disease. RESULTS: The search in the selected journals retrieved 49 papers, 36 (74%) in clinical journals, 5 (10%) in surgical journals, 2 (4%) in general medicine journals, and 6 (12%) in the neutral journal. Thirty one (63%) had a clinical origin, 13 (26%) a surgical origin, and 5 (10%) a neutral origin. Surgical journals published only surgical papers and general medicine journals published only clinical papers. Clinical journals and general medicine journals showed a higher proportion of clinical/surgical references compared to surgical journals (p<0.001) and the neutral journal (p<0.001). There was no differences in the proportion of clinical/surgical references when surgical and the neutral journal were compared (p=0.06). Clinical journals and general medicine journals showed a similar proportion of clinical/surgical references (p=0.06). CONCLUSION: Clinicians make significantly less references to surgical journals than surgeons do to clinical journals.RACIONAL: Várias doenças podem ser tratadas médica ou cirurgicamente; no entanto, a terapêutica clínica ou cirúrgica não é muitas vezes usada como diferente opção para o mesmo paciente, mas sim como diferente filosofia médica na abordagem. OBJETIVO: Verificar se os principais periódicos cirúrgicos e clínicos fazem referências aos seus congêneres, tendo a doença do refluxo gastroesofágico como um modelo de doença clínico/cirúrgica. MÉTODO: Foram revistos os cinco primeiros periódicos classificados na área de gastroenterologia, cirurgia geral e medicina geral e um jornal neutro. Os números do ano 2008 dos periódicos selecionados foram pesquisados no como lidar com a doença do refluxo gastroesofágico. RESULTADOS: Foram selecionados 49 trabalhos, 36 (74%) em revistas clínicas, 5 (10%) em revistas de cirurgia, 2 (4%) em revistas de medicina geral e 6 (12%) no jornal neutro. Trinta e um (63%) tiveram origem clínica, 13 (26%) cirúrgica, e 5 (10%) a origem foi neutra. Revistas cirúrgicas publicaram apenas artigos cirúrgicos e revistas de medicina geral, publicaram apenas trabalhos clínicos. Revistas e jornais de medicina clínica geral mostraram maior proporção de referências clínico/cirúrgicas em relação às revistas de cirurgia (p<0,001) e do jornal neutro (p<0,001). Não houve diferenças na proporção de referências clínico/cirúrgicas quando revistas cirúrgicas e a neutra foram comparadas (p= 0,06). Revistas clínicas e de medicina geral mostraram semelhante proporção de referências clínico/cirúrgicas (p=0,06). CONCLUSÃO: Os clínicos fazem referências significativamente menores para revistas cirúrgicas do que os cirurgiões fazem para as revistas clínicas.Universidade Federal de São Paulo (UNIFESP) Escola Paulista de Medicina Departmento de CirurgiaUniversity of Chicago Department of SurgeryUNIFESP, EPM, Departmento de CirurgiaSciEL

Over-Stretching Tolerant Conductors on Rubber Films by Inkjet-Printing Silver Nanoparticles for Wearables

The necessity to place sensors far away from the processing unit in smart clothes or artificial skins for robots may require conductive wirings on stretchable materials at very low-cost. In this work, we present an easy method to produce wires using only commercially available materials. A consumer grade inkjet printer was used to print a wire of silver nanoparticles with a sheet resistance below 1 W/sq. on a non-pre-strained sheet of elastic silicone. This wire was stretched more than 10,000 times and was still conductive afterwards. The viscoelastic behavior of the substrate results in a temporarily increased resistance that decreases to almost the original value. After over-stretching, the wire is conductive within less than a second. We analyze the swelling of the silicone due to the ink’s solvent and the nanoparticle film on top by microscope and SEM images. Finally, a 60 mm long stretchable conductor was integrated onto wearables, and showed that it can bear strains of up to 300% and recover to a conductivity that allows the operation of an assembled LED assembled at only 1.8 V. These self-healing wires can serve as wiring and binary strain or pressure sensors in sportswear, compression underwear, and in robotic applications.This work has been partially supported the TUM Graduate School (TUM GS), and the European Union through the fellowship H2020-MSCA-IF-2017 794885-SELFSENS. Additionally, this work was supported by the German Research Foundation (DFG) and the Technical University of Munich within the Open Access Publishing Funding Programme