A hybrid probabilistic domain decomposition algorithm suited for very large-scale elliptic PDEs

State of the art domain decomposition algorithms for large-scale boundary value problems (with $M\gg 1$ degrees of freedom) suffer from bounded strong scalability because they involve the synchronisation and communication of workers inherent to iterative linear algebra. Here, we introduce PDDSparse, a different approach to scientific supercomputing which relies on a "Feynman-Kac formula for domain decomposition". Concretely, the interfacial values (only) are determined by a stochastic, highly sparse linear system $G(\omega){\vec u}={\vec b}(\omega)$ of size ${\cal O}(\sqrt{M})$, whose coefficients are constructed with Monte Carlo simulations-hence embarrassingly in parallel. In addition to a wider scope for strong scalability in the deep supercomputing regime, PDDSparse has built-in fault tolerance and is ideally suited for GPUs. A proof of concept example with up to 1536 cores is discussed in detail

When all agents die: Analyzing the "failures" in an agent-based model of human foraging

When running a simulated social-historic scenario, we often find situations in which all agents die, even though the simulated population appears to grow in the first steps. Is this a signal that something is wrong in the computer model or its implementation? We analyze this issue in our computer model of cooperation and cultural diversity among hunter-gatherers in prehistory. We have calculated more than 11,000 possible parameter combinations, taking into account the growth and decay of the population and the availability of resources in the environment. When the initial population is too scarce or too big for the local availability of resources, it begins to decrease until it disappears. This can be a very trivial test for the Malthus condition, but we have discovered that there are other important correlations affecting social and economic factors that should be explored.Fil: Barceló, Juan A.. Universitat Autònoma de Barcelona; EspañaFil: del Castillo Bernal, María Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto Patagónico de Ciencias Sociales y Humanas; Argentina45th Annual Conference of Computer Applications and Quantitative Methods in ArchaeologyAtlantaEstados UnidosTübingen University Pres

Nuevos datos faunísticos e interacciones de moscas piojo (Diptera: Hippoboscidae) parasitando aves capturadas con redes japonesas en el Sistema Central (España)

Louse flies and keds (Diptera: Hippoboscidae) are permanent ectoparasites of birds and mammals, respectively. The abundance and species composition of the Spanish Hippoboscidae fauna is relatively little studied, with 20 species recorded so far. The aim of this pilot study is to provide new data on these ectoparasites from birds collected by mist-netting in two ringing stations in the Central System mountains in Madrid (Spain). Four polyxenous louse fly species, all of the subfamily Ornithomyinae, were obtained and identified from 13 avian hosts (Order: Passeriformes). They are, in decreasing order of abundance: Ornithomya fringillina (Curtis, 1936), Ornithophila metallica (Schiner, 1864), Ornithomya avicularia (Linnaeus, 1758), and Ornithoica turdi (Oliver in Latreille, 1811). The woodchat shrike Lanius senator Linnaeus, 1758 was the most common avian species parasitized by hippoboscids. New faunistic records and host-parasite interactions are provided for the first time in Spain.Las moscas piojo (Diptera: Hippoboscidae) son ectoparásitos permanentes de aves y mamíferos. La abundancia y composición faunística de los hipobóscidos de España está relativamente poco estudiada, con 20 especies registradas hasta el momento. El objetivo de este estudio es aportar datos nuevos sobre estos ectoparásitos a partir de hospedadores aviares recogidos con redes japonesas en dos estaciones de anillamiento del Sistema Central en Madrid (España). Se identificaron cuatro especies generalistas de moscas piojo de la subfamilia Ornithomyinae, obtenidas de 13 hospedadores aviares (Orden: Passeriformes). Estas especies son, en orden de abundancia decreciente: Ornithomya fringillina (Curtis, 1936), Ornithophila metallica (Schiner, 1864), Ornithomya avicularia (Linnaeus, 1758) y Ornithoica turdi (Oliver in Latreille, 1811). El alcaudón común Lanius senator Linnaeus, 1758 fue la especie de ave más comúnmente parasitada por hipobóscidos. Se proporcionan nuevos datos faunísticos e interacciones aves-parásito para España

Paving the way for H2AX phosphorylation: chromatin changes in the DNA damage response.

The dynamics of chromatin-associated proteins control the accessibility of DNA to essential biological transactions like transcription, replication, recombination and repair. Here, we briefly outline what is known about the chromatin changes that occur during the cellular response to DNA breakage, focusing on our recent findings revealing that the chromatin factor HP1beta is mobilized within seconds after DNA damage by an unrecognized signaling cascade mediated by casein kinase 2 (CK2) phosphorylation, paving the way for histone H2AX phosphorylation. We also show here that HP1beta mobilization is neither associated with histone H3 modification on Ser10, an alteration proposed to assist in HP1 ejection from chromatin, nor with evidence of a physical interaction between HP1beta and the CK2 regulatory subunit. Interestingly, following its rapid mobilization, we find that HP1beta gradually re-accumulates on damaged chromatin over a longer time period, suggesting that temporal changes in HP1beta dynamics and interaction with chromatin may assist in different stages of the cellular response to DNA breakage.S

Threading Through Macrocycles Enhances the Performance of Carbon Nanotubes as Polymer Fillers

In this work we study the reinforcement of polymers by mechanically interlocked derivatives of single-walled carbon nanotubes (SWNTs). We compare the mechanical properties of fibers made of polymers and of composites with pristine single-walled carbon nanotubes (SWNTs), mechanically interlocked derivatives of SWNTs (MINTs) and the corresponding supramolecular models. Improvements of both Young's modulus and tensile strength of up to 200 % were observed for the polystyrene-MINTs samples with an optimized loading of just 0.01 wt.%, while the supramolecular models with identical chemical composition and loading showed negligible or even detrimental influence. This behavior is found for three different types of SWNTs and two types of macrocycles. Molecular dynamics simulations show that the polymer adopts an elongated conformation parallel to the SWNT when interacting with MINT fillers, irrespective of the macrocycle chemical nature, whereas a more globular structure is taken upon facing with either pristine SWNTs or supramolecular models. The MINT composite architecture thus leads to a more efficient exploitation of the axial properties of the SWNTs and of the polymer chain at the interface, in agreement with experimental results. Our findings demonstrate that the mechanical bond imparts distinctive advantageous properties to SWNT derivatives as polymer fillers.Comment: 39 pages, 19 figure

Clinical-therapeutic management of drooling : review and update

Drooling is the uncontrolled leakage of saliva outside the mouth, generally as a result of difficulty in swallowing the saliva produced. Many factors contribute to drooling, though it is more commonly seen in children with brain paralysis - particularly those receiving anticonvulsivant medication. Drooling is also often seen in patients with lip sealing problems or malocclusions such as anterior open bite. Clinically, the affected patients can develop skin irritation or abrasions, problems of hygiene, unpleasant smell and - in the more severe presentations - the need to wear protectors or frequently change clothing. Treatment of this disorder is complex, and should be addressed from a multidisciplinary perspective, with planning on an individualized basis. Among the different existing managements, myofunctional therapy, behavioral change programs and drug treatments are the most widely used options, though there are also more invasive surgical techniques designed to reduce or cause submandibular saliva secretion to be rerouted towards posterior zones of the oral cavity. In any case, no scientific evidence-based management protocol has yet been established capable of affording favorable results in the majority of cases. The present study offers a review and update on the clinical and dental management aspects of drooling. © Medicina Oral S. L

Reflections on an educational program on moral and civic virtues and values in secondary schools. A case study in Mexico.

The research we present is part of the project Researching and Promoting Character Education in Latin American Secondary Schools funded by the Templeton World Charity Foundation.In this research work we present a case study, focusing on the values program implemented in a Mexican public school in the central area of the country. Our exploration of the capacity of the school when implementing the values program is based on the analysis of documents provided by the school which are related with the project, semi-structured interviews, in-depth interviews, images and the participatory observation carried out in the school over a period of three weeks. The wealth of informants (principals, teachers, pupils and parents) allowed us to gather a broader variety of information on the reality of the values program applied