Serpentine channels: micro -- rheometers for fluid relaxation times

We propose a novel device capable of measuring the relaxation time of viscoelastic fluids as small as 1\,ms. In contrast to most rheometers, which by their very nature are concerned with producing viscometric or nearly-viscometric flows, here we make use of an elastic instability which occurs in the flow of viscoelastic fluids with curved streamlines. To calibrate the rheometer we combine simple scaling arguments with relaxation times obtained from first normal-stress difference data measured in a classical shear rheometer. As an additional check we also compare these relaxation times to those obtained from Zimm theory and good agreement is observed. Once calibrated, we show how the serpentine rheometer can be used to access smaller polymer concentrations and lower solvent viscosities where classical measurements become difficult or impossible to use due to inertial and/or resolution limitations. In the absence of calibration the serpentine channel can still be a very useful comparative or index device.Comment: accepted for for publication in Lab on a chi

Estimating the fitness effect of an insertion sequence

Since its discovery, mobile DNA has fascinated researchers. In particular, many researchers have debated why insertion sequences persist in prokaryote genomes and populations. While some authors think that insertion sequences persist only because of occasional beneficial effects they have on their hosts, others argue that horizontal gene transfer is strong enough to overcome their generally detrimental effects. In this study, we model the long-term fate of a prokaryote cell population, of which a small proportion of cells has been infected with one insertion sequence per cell. Based on our model and the distribution of IS5, an insertion sequence for which sufficient data is available in 525 fully sequenced proteobacterial genomes, we show that the fitness cost of insertion sequences is so small that they are effectively neutral or only slightly detrimental. We also show that an insertion sequence infection can persist and reach the empirically observed distribution if the rate of horizontal gene transfer is at least as large as the fitness cost, and that this rate is well within the rates of horizontal gene transfer observed in nature. In addition, we show that the time needed to reach the observed prevalence of IS5 is unrealistically long for the fitness cost and horizontal gene transfer rate that we computed. Occasional beneficial effects may thus have played an important role in the fast spreading of insertion sequences like IS

A survey of bacterial insertion sequences using IScan

Bacterial insertion sequences (ISs) are the simplest kinds of bacterial mobile DNA. Evolutionary studies need consistent IS annotation across many different genomes. We have developed an open-source software package, IScan, to identify bacterial ISs and their sequence elements—inverted and target direct repeats—in multiple genomes using multiple flexible search parameters. We applied IScan to 438 completely sequenced bacterial genomes and 20 IS families. The resulting data show that ISs within a genome are extremely similar, with a mean synonymous divergence of Ks = 0.033. Our analysis substantially extends previously available information, and suggests that most ISs have entered bacterial genomes recently. By implication, their population persistence may depend on horizontal transfer. We also used IScan's ability to analyze the statistical significance of sequence similarity among many IS inverted repeats. Although the inverted repeats of insertion sequences are evolutionarily highly flexible parts of ISs, we show that this ability can be used to enrich a dataset for ISs that are likely to be functional. Applied to the thousands of genomes that will soon be available, IScan could be used for many purposes, such as mapping the evolutionary history and horizontal transfer patterns of different IS

A reforma da Matemática Moderna em contextos Ibero-Americanos

José Manuel Matos e Wagner Rodrigues Valente (Editores) © UIED, Unidade de Investigação, Educação e Desenvolvimento 1ª edição: Outubro de 2010 Tiragem: 200 exemplares ISBN: 978-989-691-033-4 Depósito legal: 317563/10 UIED | Colecção Educação e Desenvolvimento Faculdade de Ciência e Tecnologia da Universidade Nova de Lisboa Campus da Caparica 2829-516 Caparica, Portugal Tel.: +351 212948383 e-mail: [email protected] A UIED é uma Unidade de Investigação financiada pela Fundação para a Ciência e a Tecnologia.A reforma da Matemática Moderna em contextos ibero-americanos é um livro que recolhe estudos da autoria de especialistas da América Latina e da Península Ibérica. Trata-se de um dos resultados do projecto A Matemática Moderna nas escolas do Brasil e de Portugal: Estudos históricos comparativos financiado pela Fundação para a Ciência e a Tecnologia portuguesa e pela Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) brasileira. José Manuel Matos e Wagner Rodrigues Valente Editores UIE

A survey of bacterial insertion sequences using IScan

Bacterial insertion sequences (ISs) are the simplest kinds of bacterial mobile DNA. Evolutionary studies need consistent IS annotation across many different genomes. We have developed an open-source software package, IScan, to identify bacterial ISs and their sequence elements—inverted and target direct repeats—in multiple genomes using multiple flexible search parameters. We applied IScan to 438 completely sequenced bacterial genomes and 20 IS families. The resulting data show that ISs within a genome are extremely similar, with a mean synonymous divergence of Ks = 0.033. Our analysis substantially extends previously available information, and suggests that most ISs have entered bacterial genomes recently. By implication, their population persistence may depend on horizontal transfer. We also used IScan's ability to analyze the statistical significance of sequence similarity among many IS inverted repeats. Although the inverted repeats of insertion sequences are evolutionarily highly flexible parts of ISs, we show that this ability can be used to enrich a dataset for ISs that are likely to be functional. Applied to the thousands of genomes that will soon be available, IScan could be used for many purposes, such as mapping the evolutionary history and horizontal transfer patterns of different ISs

Who gets phished? Insights from a Contextual Clustering Analysis Across Three Continents

Phishing attacks are one of the most prevalent cybersecurity threats to modern organizations. As a result, researchers and practitioners alike have pooled their strengths to understand who is most at risk of falling for phishing attacks. Since recent work calls for consideration of discrete context dimensions when examining phishing susceptibility, we use cluster analysis in conjunction with a large-scale phishing experiment to identify and scrutinize highly deceivable employees across three continents based on contextual influencing factors. The results reveal salient similarities between employee groups in Europe, Australia, and North America. Consequently, our findings underscore the importance of classifying employees based on discrete contextual characteristics impacting their phishing susceptibility. Furthermore, the identified clusters have important implications for policymakers, awareness programs, and anti-phishing interventions, as they allow to better target individuals based on contextual attributes

Seasonal circulation over the Catalan inner-shelf (northwest Mediterranean Sea)

This study characterizes the seasonal cycle of the Catalan inner-shelf circulation using observations and complementary numerical results. The relation between seasonal circulation and forcing mechanisms is explored through the depth-averaged momentum balance, for the period between May 2010 and April 2011, when velocity observations were partially available. The monthly-mean along-shelf flow is mainly controlled by the along-shelf pressure gradient and by surface and bottom stresses. During summer, fall, and winter, the along-shelf momentum balance is dominated by the barotropic pressure gradient and local winds. During spring, both wind stress and pressure gradient act in the same direction and are compensated by bottom stress. In the cross-shelf direction the dominant forces are in geostrophic balance, consistent with dynamic altimetry data. Key Points A hydrodynamic model is implemented for the first time in Catalan inner-shelf. Frictional and pressure gradient are revealed as the main forcing mechanisms A clear seasonal pattern is found in the current velocity.Peer ReviewedPostprint (published version

Poster: Benchmarking Financial Data Feed Systems

Data-driven solutions for the investment industry require event-based backend systems to process high-volume financial data feeds with low latency, high throughput, and guaranteed delivery modes. At vwd we process an average of 18 billion incoming event notifications from 500+ data sources for 30 million symbols per day and peak rates of 1+ million notifications per second using custom-built platforms that keep audit logs of every event. We currently assess modern open source event-processing platforms such as Kafka, NATS, Redis, Flink or Storm for the use in our ticker plant to reduce the maintenance effort for cross-cutting concerns and leverage hybrid deployment models. For comparability and repeatability we benchmark candidates with a standardized workload we derived from our real data feeds. We have enhanced an existing light-weight open source benchmarking tool in its processing, logging, and reporting capabilities to cope with our workloads. The resulting tool wrench can simulate workloads or replay snapshots in volume and dynamics like those we process in our ticker plant. We provide the tool as open source. As part of ongoing work we contribute details on (a) our workload and requirements for benchmarking candidate platforms for financial feed processing; (b) the current state of the tool wrench.Comment: Authors' version of the accepted submission; final version published by ACM as part of the proceedings of DEBS '19: The 13th ACM International Conference on Distributed and Event-based Systems (DEBS '19); 2 pages, 2 figure

The exploration of potential

In dieser Diplomarbeit, welche aus drei miteinander verflochtenen und zueinander durchlässigen Teilen besteht, wird das Phänomen Improvisation aus unterschiedlichen Perspektiven beleuchtet. Zentral für meine Beobachtungen sind vorallem die Entwicklungen und Möglichkeiten für die Praxis von Improvisation in Wien. Zuerst stelle ich diverse Definitionen und Gebräuche aus den darstellenden Künsten vor. Danach kommt ein grob angerissener historischer Überblick über die Entwicklung von Improvisation im Tanz, gefolgt von Betrachtungen im künstlerischen Umfeld der Postmoderne. Hier befinden sich die wichtigsten Impulsgeber im New York der 1960er und 1970er Jahre, die wesentlich zu einer Verbreitung von improvisatorischen Ansätzen im Euro-Amerikanischen kulturellen Kontext beigetragen haben. Indem ich die Ansätze von Foucault zu den regulativen Mechanismen staatlicher Kontrolle erläutere, wird ersichtlich das uns Improvisation zu einer aktiven und selbstbestimmten Gestaltung unseres Habitus ermächtigen kann, was von den reformistischen Theatergruppen aus dieser Zeit auch vehement propagiert wurde. Im zweiten Teil dieser Arbeit stelle ich meine theoretischen Überlegungen zu den Themen Körper und Geschlecht, Techniken des Körpers, den Prozess der Wissensgenerierung anhand von Konzepten von Tim Ingold dar. Letztlich präsentiere ich die prozessuale Methodologie welche in dieser Diplomarbeit zur Anwendung gekommen ist, und reflektiere in kritischer Weise die junge Disziplin der Sensory Ethnography. Im dritten und letzten Teil präsentiere ich alle Erkenntnisse die ich aus dem Forschungsprozess gewinnen konnte. Zuerst führe ich Erkenntnisse aus den Interviews in Form von zusammengefassten Kernaussagen zu jeder Interviewkategorie an. Danach werden Effekte von langjähriger körperlicher Praxis von Improvisation auf den Lebensweg besprochen, wobei Hyperawareness, der Durchdringungs-Effekt, Überlegungen über das in Zentraleuropa üblich Zeitverständnis, Tuning und Swarming zentrale Punkte der Argumentation darstellen. Indem ich mich an einem Begriff von Peter Sloterdijk anlehne, spreche ich von Anthropotechnik, um die Präsentation der Forschungserkenntnisse abzuschließen. Am Ende dieser Arbeit über Improvisation in Wien resümiere ich noch einmal kurz die zentralen Aussagen dieser Diplomarbeit in einer Conclusio wobei ich nochmals auf die anfangs genannten Hypothesen zurückkomme und diese neuerlich kritisch bespreche.This thesis for diploma deals with improvisation in various aspects of the phenomenon in a Viennese context. It consists of three parts: The first part displays definitions and approaches of improvisation as it is used and perceived from the perspective of the performing arts, where I provide a historic overview about the development of improvisation as a tool for dance and performance. Later, I portray the various forms of experimental approaches of performance collectives and groups from the 1960s and 1970s. In the end, I discuss Foucault’s notion about the regulative disciplines of the modern nation state, and fact that improvisation can be used to alter and transform one’s habitus, thus making available an alteration to ‘social choreography’, which ultimately holds the potential for social reformation. In the second part of this work, I introduce several theoretical concepts about the body and gender, Techniques of the Body, and the process of knowledge-generation following the arguments of Tim Ingold. Later I introduce processual methodology as well as Sensory Ethnography as major orientations for conducting my one-year participant observation. In the third and last part I arrange all the findings, displaying first the bundled statements of all the interviewees together and later the effects of improvisation on the lifecourse. These central findings and insights to this thesis for diploma are hyperawareness, the saturation-effect, observations on timely use in a Central European cultural context, the phenomena of tuning and swarming, and as a final finding the beneficial aspects of Anthropotechnique as I understand it. I close this thesis with a conclusion where first the central statements are consolidated and where I finally re-evaluate my initial hypotheses

Optical microtopographic characterization of arqueological ceramics

Optics and optics and photonics based inspection tools and methods had expensively proven their invaluable importance in the preservation of cultural heritage and artwork. The non-invasive inspection of the 3D shape of objects and of the micro-relief structure of its surfaces can be of high importance in the characterization process required in most works of restoration or preservation of archeological artwork. In this communication we will report on a method of optical non-invasive microtopographic characterization of the surface of archeological ceramics. The samples used in this study are pre-historical and pre-colonial ceramics and pottery of tribes in the Paranaiba valley in Minas Gerais, Brazil. The pottery found is decorated with incisions with different geometric distributions and levels of complexity corresponding to two periods of indigenous Indian occupations: one from a period dated at 1,095 ± 186 years ago and another of the early nineteenth century dated between 212 ± 19 years and 190 ± 30 years ago seemingly corresponding to the occupation of the territory by southern Kayapós tribes.info:eu-repo/semantics/publishedVersio