Avatar: A Time- and Space-Efficient Self-Stabilizing Overlay Network

Overlay networks present an interesting challenge for fault-tolerant computing. Many overlay networks operate in dynamic environments (e.g. the Internet), where faults are frequent and widespread, and the number of processes in a system may be quite large. Recently, self-stabilizing overlay networks have been presented as a method for managing this complexity. \emph{Self-stabilizing overlay networks} promise that, starting from any weakly-connected configuration, a correct overlay network will eventually be built. To date, this guarantee has come at a cost: nodes may either have high degree during the algorithm's execution, or the algorithm may take a long time to reach a legal configuration. In this paper, we present the first self-stabilizing overlay network algorithm that does not incur this penalty. Specifically, we (i) present a new locally-checkable overlay network based upon a binary search tree, and (ii) provide a randomized algorithm for self-stabilization that terminates in an expected polylogarithmic number of rounds \emph{and} increases a node's degree by only a polylogarithmic factor in expectation

Relationship Between Exercise Heart Rate and Music Tempo Preference

The present study examined the predicted positive and linear relationship (Iwanaga, 1995a,1995b) between exercise heart rate and music tempo preference. Initially, 128 undergraduates (M 3 age = 20.0 years, SD = 0.9 years) were surveyed to establish their three favorite music artists of all time. A separate experimental group of 29 undergraduates (M age = 20.3 years, SD = 1.2 years) selected the music of a single artist from a choice of the three highest-rated artists from the earlier survey. They reported their preference for slow, medium, and fast tempo music selections from the same artist in each of three treadmill walking conditions at 40%, 60%, and 75% maximal heart rate reserve. A mixed-model 3 x 3 x 2 (Exercise Intensity x Music Tempo x Gender) analysis of variance was used to analyze the data. Results indicated there was no three-way interaction for music preference. There was however a significant (p < .05) two-way interaction for Exercise Intensity x Music Tempo (partial η2 = .09) and a significant (p < .05) main effect for music tempo, with large differences evident between preference for medium tempo versus slow tempo and fast tempo versus slow tempo music at all exercise intensities (partial η2 = .78). Participants reported a preference for both medium and fast tempo music at low and moderate exercise intensities, and for fast tempo music at high intensity. Only partial support was found for the expected linear relationship between exercise intensity and music tempo preference

Commentary on the detection of bubble activity generated in ex-vivo tissue by high intensity focused ultrasound (HIFU) with respect to the generation of therapeutic lesions in tissue for the treatment of cancer

Cancer treatment by extracorporeal high intensity focused ultrasound (HIFU) is constrained by the time needed to ablate relevant tumour volumes clinically. Controlled cavitation might be used to optimise HIFU treatments, but such control requires a greater understanding of its role in lesion formation, and the provision of appropriate techniques to monitor cavitation in tissue. During HIFU exposure various forms of cavitation can occur: acoustic cavitation (both non-inertial and inertial), and bubble formation due to two thermally-driven effects (the vaporisation of liquid into vapour, and the exsolution of formerly dissolved permanent gas out of the liquid and into gas spaces). Different forms of cavitation gives rise to characteristic signals that can be monitored during HIFU. Furthermore, the character of the signal can change depending on the stage of the cavitation in question (nucleation, established cavitation, population effects etc.). Prior to undertaking experiments using tissue, studies were performed by exposing degassed water. The aim of these experiments was to test a detection system in a minimally attenuating medium known to cavitate, in order to provide data for comparison with ex-vivo tissue results.This report is written in support of the journal paper “A Study of Bubble Activity Generated in Ex-Vivo Tissue by High Intensity Focused Ultrasound (HIFU)” by the same authors (McLaughlan et al. 2010). It outlines supporting material for the discussion and conclusions contained in that paper, a study involving monitoring clinically relevant HIFU exposures in degassed water and ex-vivo bovine liver. Monitoring is accomplished using a suite of cavitation detection techniques (exploiting passive and active acoustics, audible and ultrasonic emissions and electrical drive power fluctuations). The aim of the paper is to allow informed progress towards a monitoring system specifically tailored for use during clinical HIFU treatment

Poliquetos del Seno Aysén, Chile: distribución, abundancia y comparaciones biogeográficas con la fauna de poliquetos de áreas someras de la Antártida y la provincia de Magallanes

This paper analyzes the composition, abundance and biogeographical relationship of the benthic polychaetes collected in three shallow subtidal locations (mouth of Cuervo and Condor rivers and Acantilada Bay) from Aysen Fjord, AF, Chile (45ºS, 73ºW), and provides a comparison with data on shallow soft-bottom polychaetes from Antarctica and other locations of the Magellan Province: Dalcahue Channel, DC (42º22´S, 73º39´W), Puerto Cisnes, Puyuhuapi Channel, PC (44º43´S, 72º42´W) and Magellan Straits, MS. AF polychaete fauna comprises 38 species, the macrobenthic taxon being most representative in terms of abundance and species richness. The importance of polychaetes seems to be higher in fjords than in channels. Low numbers of common species were detected among DC, PC, MS and AF, indicating differences along the influence area of the Cape Horn Current or along the Magellan Province. The polychaetes from AF show low affinities with Antarctica; maximum number of common species was observed with the Antarctic Peninsula, whereas the lowest values were recorded from locations in the Ross and Weddell Seas. Coincidence in some ecological attributes between AF and Antarctica indicate that polychaetes may play an important and similar ecological role in both environments.Se analiza la composición, abundancia y relaciones biogeográficas de poliquetos bentónicos recolectados en tres localidades someras (desembocadura de los ríos Cuervo y Cóndor y Bahía Acantilada) del Seno Aysén, SA, Chile (45ºS, 73ºO), y se efectúa una comparación con los poliquetos de la Antártida y otras localidades de la Provincia de Magallanes: Canal Dalcahue, CD (42º22’S, 73º39’O), Puerto Cisnes, Canal Puyuhuapi, CP (44º43’S, 72º42’O) y Estrecho de Magallanes, EM. La poliquetofauna del SA se compone de 38 especies, siendo el taxón más representativo del macrobentos en términos tanto de abundancia como de riqueza de especies. La importancia de los poliquetos parece mayor en fiordos que en canales. Se detectaron escasas afinidades entre CD, CP, EM y SA, indicando diferencias geográficas del papel de los poliquetos en la Provincia de Magallanes o en el área influenciada por la corriente del Cabo de Hornos. Existen escasas afinidades entre los poliquetos del SA y la Antártida; el mayor número de especies comunes fue compartido con la Península Antártica, mientras que ocurría lo contrario con localidades de los Mares de Ross y Weddell. La similitud de algunos atributos ecológicos entre SA y la Antártida sugieren que los poliquetos juegan un papel ecológico similar en ambos ambientes

Toward collaborative open data science in metabolomics using Jupyter Notebooks and cloud computing

Background A lack of transparency and reporting standards in the scientific community has led to increasing and widespread concerns relating to reproduction and integrity of results. As an omics science, which generates vast amounts of data and relies heavily on data science for deriving biological meaning, metabolomics is highly vulnerable to irreproducibility. The metabolomics community has made substantial efforts to align with FAIR data standards by promoting open data formats, data repositories, online spectral libraries, and metabolite databases. Open data analysis platforms also exist; however, they tend to be inflexible and rely on the user to adequately report their methods and results. To enable FAIR data science in metabolomics, methods and results need to be transparently disseminated in a manner that is rapid, reusable, and fully integrated with the published work. To ensure broad use within the community such a framework also needs to be inclusive and intuitive for both computational novices and experts alike. Aim of Review To encourage metabolomics researchers from all backgrounds to take control of their own data science, mould it to their personal requirements, and enthusiastically share resources through open science. Key Scientific Concepts of Review This tutorial introduces the concept of interactive web-based computational laboratory notebooks. The reader is guided through a set of experiential tutorials specifically targeted at metabolomics researchers, based around the Jupyter Notebook web application, GitHub data repository, and Binder cloud computing platform

Mathematical modeling of injury healing process under the action of an active pharmaceutical ingredient (API)

In this work we carried out the mathematical modeling of the wound healing process, which is a well documented topic in medical and biological practice; but mathematically speaking there are still too much to be done for a clear understanding of the healing phenomom. Here we contribute to the mathematical modelling by using chemical kinetic concepts and mathematical tools, from which we have been able to formulate a system of ordinary differential equations of initial value, whose solution is presented graphically in front of a case study, where we have tested an active pharmaceutical principle with respect to its effectiveness. Finally, the speed of the healing process for such a case study produced an excellent agreement with experimental data that has been omitted due to confidentiality.En este trabajo llevamos a cabo el modelado matemático del proceso de curación de heridas, que es un tema bien documentado en la práctica médica y biológica; pero matemáticamente hablando, todavía hay mucho por hacer para una comprensión clara del fenómeno curativo. Aquí contribuimos al modelado matemático mediante el uso de conceptos de cinética química y herramientas matemáticas, a partir de los cuales hemos podido formular un sistema de ecuaciones diferenciales ordinarias de valor inicial, cuya solución se presenta gráficamente frente a un estudio de caso, donde hemos probado un principio farmacéuticamente activo con respecto a su eficacia. Finalmente, la velocidad del proceso de curación para tal estudio de caso produjo un excelente acuerdo con los datos experimentales, que se han omitido debido a la confidencialidad

The 3′ Region of the Chicken Hypersensitive Site-4 Insulator Has Properties Similar to Its Core and Is Required for Full Insulator Activity

Chromatin insulators separate active transcriptional domains and block the spread of heterochromatin in the genome. Studies on the chicken hypersensitive site-4 (cHS4) element, a prototypic insulator, have identified CTCF and USF-1/2 motifs in the proximal 250 bp of cHS4, termed the “core”, which provide enhancer blocking activity and reduce position effects. However, the core alone does not insulate viral vectors effectively. The full-length cHS4 has excellent insulating properties, but its large size severely compromises vector titers. We performed a structure-function analysis of cHS4 flanking lentivirus-vectors and analyzed transgene expression in the clonal progeny of hematopoietic stem cells and epigenetic changes in cHS4 and the transgene promoter. We found that the core only reduced the clonal variegation in expression. Unique insulator activity resided in the distal 400 bp cHS4 sequences, which when combined with the core, restored full insulator activity and open chromatin marks over the transgene promoter and the insulator. These data consolidate the known insulating activity of the canonical 5′ core with a novel 3′ 400 bp element with properties similar to the core. Together, they have excellent insulating properties and viral titers. Our data have important implications in understanding the molecular basis of insulator function and design of gene therapy vectors

The parabola theorem on continued fractions

Using geometric methods borrowed from the theory of Kleinian groups, we interpret the parabola theorem on continued fractions in terms of sequences of Möbius transformations. This geometric approach allows us to relate the Stern–Stolz series, which features in the parabola theorem, to the dynamics of certain sequences of Möbius transformations acting on three-dimensional hyperbolic space. We also obtain a version of the parabola theorem in several dimensions