Modeling Scalability of Distributed Machine Learning

Present day machine learning is computationally intensive and processes large amounts of data. It is implemented in a distributed fashion in order to address these scalability issues. The work is parallelized across a number of computing nodes. It is usually hard to estimate in advance how many nodes to use for a particular workload. We propose a simple framework for estimating the scalability of distributed machine learning algorithms. We measure the scalability by means of the speedup an algorithm achieves with more nodes. We propose time complexity models for gradient descent and graphical model inference. We validate our models with experiments on deep learning training and belief propagation. This framework was used to study the scalability of machine learning algorithms in Apache Spark.Comment: 6 pages, 4 figures, appears at ICDE 201

Science and technology in Russia: problems and prospects

'Der vorliegende Bericht gibt einen Überblick über die Entwicklung der russischen Wissenschaft in den letzten Jahren. Er zeigt die Probleme, die in allen Bereichen des Forschungs- und Entwicklungsprozesses auftreten, und untersucht die Ursachen für die krisenhafte Situation. Darüber hinaus erörtert er, welche Auswege sich eröffnen, die es erlauben, daß Wissenschaft in Rußland wieder den angemessenen Platz in der Gesellschaft einnimmt und eine aktive Rolle beim Übergang zu Demokratie und Marktwirtschaft spielt. Der Bericht basiert auf statistischen und faktologischen Materialien, die Parlament und Regierung veröffentlicht haben. Darüber hinaus stützt er sich auf offizielle Dokumente, statistische Jahrbücher, Informationen des russischen Ministeriums für Wissenschaft und Technologie und der Akademie der Wissenschaften sowie auf Publikationen in Fachzeitschriften und der allgemeinen Presse.' (Autorenreferat)'The following report provides a survey of what has happened in Russian science in recent years. It illustrates the problems that exist in all areas of the research and development process and examines the reasons for the state of crisis. It then discusses possible ways out of the crisis that would allow Russian science once again to assume its proper place in society and to play an active role in the transition to democracy and a market economy. The report is based on statistical and factual Information published by the Russian parliament and government as well as on official documents, statistical yearbooks and Information provided by the Russian Ministry of Science and Technology and the Academy of Sciences. It also draws on articles published in specialist periodicals and in the press.' (author's abstract

Introducing baselines for Russian named entity recognition

Current research efforts in Named Entity Recognition deal mostly with the English language. Even though the interest in multi-language Information Extraction is growing, there are only few works reporting results for the Russian language. This paper introduces quality baselines for the Russian NER task. We propose a corpus which was manually annotated with organization and person names. The main purpose of this corpus is to provide gold standard for evaluation. We implemented and evaluated two approaches to NER: knowledge-based and statistical. The first one comprises several components: dictionary matching, pattern matching and rule-based search of lexical representations of entity names within a document. We assembled a set of linguistic resources and evaluated their impact on performance. For the data-driven approach we utilized our implementation of a linear-chain CRF which uses a rich set of features. The performance of both systems is promising (62.17% and 75.05% F1 measure), although they do not employ morphological or syntactical analysis. © 2013 Springer-Verlag

Divergent karyotypes in five genera of the African endemic fish family Distichodontidae (Cithariniformes, Osteichthyes)

The African family Distichodontidae comprises 109 species in 16 genera. Up-to-date cytogenetic information was available for the only distichodontid species Distichodus affinis Günther, 1873. Here we report chromosome number and morphology in: Distichodus engycephalus Günther, 1864 (2n = 52, FN = 104), Ichthyborus besse (Joannis, 1835) (2n = 46, FN = 92), Nannocharax niloticus (Joannis, 1835) (2n = 54, FN = 106) and three taxa, Nannaethiops bleheri Géry et Zarske, 2003, Nannaethiops sp., and Neolebias unifasciatus Steindachner, 1894, that exhibit the same karyotypes (2n = 50, FN = 98). To confirm the Nannaethiops Günther, 1872 and Neolebias Steindachner, 1894 species identification, mt-DNA sequences of the two markers (COI and 16S rRNA) were obtained from karyotyped specimens and compared with the relevant sequences accessible from GenBank. The great prevalence of biarmed chromosomes (the karyotypes of most species contain exclusively biarmed chromosomes) is a distinctive characteristic of Distichodontidae and Cithariniformes as a whole

Who are you, Griselda? A replacement name for a new genus of the Asiatic short-tailed shrews (Mammalia, Eulipotyphla, Soricidae): molecular and morphological analyses with the discussion of tribal affinities

The first genetic study of the holotype of the Gansu short-tailed shrew, Blarinella griselda Thomas, 1912, is presented. The mitochondrial analysis demonstrated that the type specimen of B. griselda is close to several recently collected specimens from southern Gansu, northern Sichuan and Shaanxi, which are highly distinct from the two species of Asiatic short-tailed shrews of southern Sichuan, Yunnan, and Vietnam, >B. quadraticauda and B. wardi. Our analysis of four nuclear genes supported the placement of B. griselda as sister to B. quadraticauda / B. wardi, with the level of divergence between these two clades corresponding to that among genera of Soricinae. A new generic name, Parablarinella, is proposed for the Gansu short-tailed shrew. Karyotypes of Parablarinella griselda(2n = 49, NFa = 50) and B. quadraticauda (2n = 49, NFa = 62) from southern Gansu are described. The tribal affinities of Blarinellini and Blarinini are discussed.Copyright Anna A. Bannikova et al. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. The attached file is the published version of the article

Observation of Extensive Chromosome Axis Remodeling during the "Diffuse-Phase" of Meiosis in Large Genome Cereals

The production of balanced fertile haploid gametes requires the faithful separation of paired (synapsed) chromosomes toward the end of meiotic prophase I (desynapsis). This involves the timely dissolution of the synaptonemal complex during the pachytene-diplotene transition, a stage traditionally referred to as the "diffuse stage." In species with large genomes such as, barley (Hordeum vulgare L.) and wheat (Triticum aestivum L.) we know most about the early stages of meiotic prophase I. There, synapsis initiates at the telomeric ends of chromosomes and progresses toward the centromeric regions through the ordered assembly of the synaptonemal complex (SC). Synapsis is impacted by recombination (crossing over, CO) which locally modifies the extent of chromatin compaction and extension. CO is uneven along the chromosomes, occurring mainly toward the telomeric regions resulting in a highly skewed distribution of recombination events. However, we know very little about the process of desynapsis which occurs during the "diffuse stage," where the synapsed and recombined chromosomes faithfully desynapse and separate into daughter cells. Here, using 3D-SIM super-resolution immuno-cytology combined with the use of antibodies directed against two crucial SC proteins, ASY1 and ZYP1, we followed the whole of meiosis I (i.e., both synapsis and desynapsis) in both barley and wheat. We showed that synapsis forms a characteristic tri-partite SC structure in zygotene (more clearly seen in barley). Toward the end of meiosis I, as the SC starts to disassemble, we show that extensive chromosome axis remodeling results in the formation of characteristic "tinsel-like" structures in both wheat and barley. By using amutant (des10) that is severely compromised in polymerization of ZYP1during synapsis, we show that tinsel structure formation during SC dissolution is not dependant on full synapsis and may relate instead to changes in expansion stress. Our observations highlight a potentially new role for ASYNAPSIS1 (ASY1) in desynapsis, in addition to chromosome synapsis and cohesion

Implant removal associated complications in children with limb fractures due to trauma

Surger