A Scalable Asynchronous Distributed Algorithm for Topic Modeling

Learning meaningful topic models with massive document collections which contain millions of documents and billions of tokens is challenging because of two reasons: First, one needs to deal with a large number of topics (typically in the order of thousands). Second, one needs a scalable and efficient way of distributing the computation across multiple machines. In this paper we present a novel algorithm F+Nomad LDA which simultaneously tackles both these problems. In order to handle large number of topics we use an appropriately modified Fenwick tree. This data structure allows us to sample from a multinomial distribution over $T$ items in $O(\log T)$ time. Moreover, when topic counts change the data structure can be updated in $O(\log T)$ time. In order to distribute the computation across multiple processor we present a novel asynchronous framework inspired by the Nomad algorithm of \cite{YunYuHsietal13}. We show that F+Nomad LDA significantly outperform state-of-the-art on massive problems which involve millions of documents, billions of words, and thousands of topics

Computing Web-scale Topic Models using an Asynchronous Parameter Server

Topic models such as Latent Dirichlet Allocation (LDA) have been widely used in information retrieval for tasks ranging from smoothing and feedback methods to tools for exploratory search and discovery. However, classical methods for inferring topic models do not scale up to the massive size of today's publicly available Web-scale data sets. The state-of-the-art approaches rely on custom strategies, implementations and hardware to facilitate their asynchronous, communication-intensive workloads. We present APS-LDA, which integrates state-of-the-art topic modeling with cluster computing frameworks such as Spark using a novel asynchronous parameter server. Advantages of this integration include convenient usage of existing data processing pipelines and eliminating the need for disk writes as data can be kept in memory from start to finish. Our goal is not to outperform highly customized implementations, but to propose a general high-performance topic modeling framework that can easily be used in today's data processing pipelines. We compare APS-LDA to the existing Spark LDA implementations and show that our system can, on a 480-core cluster, process up to 135 times more data and 10 times more topics without sacrificing model quality.Comment: To appear in SIGIR 201

Change detection in categorical evolving data streams

Detecting change in evolving data streams is a central issue for accurate adaptive learning. In real world applications, data streams have categorical features, and changes induced in the data distribution of these categorical features have not been considered extensively so far. Previous work on change detection focused on detecting changes in the accuracy of the learners, but without considering changes in the data distribution. To cope with these issues, we propose a new unsupervised change detection method, called CDCStream (Change Detection in Categorical Data Streams), well suited for categorical data streams. The proposed method is able to detect changes in a batch incremental scenario. It is based on the two following characteristics: (i) a summarization strategy is proposed to compress the actual batch by extracting a descriptive summary and (ii) a new segmentation algorithm is proposed to highlight changes and issue warnings for a data stream. To evaluate our proposal we employ it in a learning task over real world data and we compare its results with state of the art methods. We also report qualitative evaluation in order to show the behavior of CDCStream

Beta Secondary Deuterium Kinetic Isotope Effects on the Thermal Stereomutations of 1,2-Diphenylcyclopropanes

(+)-(1S,2S)-trans-1,2-Diphenylcyclopropane and (-)-(1R,2R)-trans- l,2-diphenyl-3,3-t2-cyclopropane at 234 °C interconvert reversibly with the corresponding enantiomers and css-1,2-diphenyl cyclopropanes. For the unlabeled trans isomer, the ratio of rate constants for one-center epimerization (k) and two-center turnover (&12) was found to be 1.1. A small normal k^Jk-Q effect, 3% per deuterium, was observed for the rate constant for one-center epimerization (k1); a substantial normal k-^lk-Q effect, 17% per deuterium, was observed for the rate constant for two-center turnover (k^). Thus different transition structures, presumably EF and EE 1,3-diphenyltrimethylene diradicals, dominate the two sorts of stereomutations

Clinical and pathologic remission of pediatric ulcerative colitis with serum-derived bovine immunoglobulin added to the standard treatment regimen

Ulcerative colitis (UC) is a chronic inflammatory bowel disease that is particularly troublesome for pediatric patients, as current therapeutic options consist of biologic agents and steroids which alter the immune response and have the harmful side effect of leaving the patient more susceptible to opportunistic infections and eventual surgery. Another option for therapy exists in the form of serum-derived bovine immunoglobulin/protein isolate (SBI), the key ingredient in a medical food, EnteraGam®. The FDA has reviewed the safety of SBI and issued a no challenge letter to the generally recognized as safe (GRAS) findings for this medical food. The product also has no known food or drug interactions, no significant adverse effects, and no contraindications, save for beef allergy. SBI has been shown to induce clinical remission in adult populations and to decrease markers of inflammation in pediatric patients. Here, we present a detailed case of pediatric UC, including documentation of mucosal healing and decrease in pediatric UC activity index in a difficult to treat pediatric patient, after the addition of SBI to this patient’s treatment regimen

Trabajo social en España. De los recortes sociales a la arena pública

Los derechos humanos están sufriendo severos recortes con la excusa de que las políticas internacionales exigen ajustes económicos. Hay un cambio drástico de política. Las universidades y trabajadores sociales profesionales junto con las organizaciones civiles, están participando en el debate público y denunciando la calidad de estas políticas o su inexistencia cuando no las hay.La investigación que lleva a estos resultados ha recibido financiación por el People programme (Marie Curie Actions) del European Union's seventh framework programme Fp7/2007-2013 bajo el acuerdo Rea de subvención n.318938

Advocacy and policy influencing for social change: Responsibility of social workers and implications for training

La incidencia en las políticas sociales es una importante función profesional de las trabajadoras sociales que precisa ser integrada en la educación teórica y práctica en Trabajo Social. Este artículo indaga sobre los fundamentos de esta función de incidencia en los cambios sociales promoviendo políticas sociales que reconozcan los derechos humanos. Partiendo de los referentes internacionales del trabajo social, se analiza el caso de España teniendo en cuenta los códigos deontológicos, los planes de estudio en Trabajo Social, la práctica profesional y los nuevos Grados en Trabajo Social. Se concluye planteando interrogantes sobre el grado de responsabilidad y de implicación de las universidades y Colegios profesionales en coherencia con los principios y valores del Trabajo Social.Advocacy and social policy influencing is an important professional role of social workers that needs to be integrated into education and training on social work. This article explores the fundamentals of this advocacy role in social change through social policies that recognize human rights. Based on the international benchmarks of social work, the case of Spain is analyzed considering ethical codes, the curricula in social work, professional practice and the new Degree in Social Work. The article raises some questions about the degree of responsibility and involvement that universities and professional associations have, in coherence with the principles and values of social work.Este trabajo está financiado en parte, por el proyecto FP7 PEOPLE-2012-IRSES. Grant Agreement Number 318938. Civil Engagement in Social Work: Developing Global Models (CIVIL-SW). PIRSES-GA-2012-318938

Software Licenses in Context: The Challenge of Heterogeneously-Licensed Systems

The prevailing approach to free/open source software and licenses has been that each system is developed, distributed, and used under the terms of a single license. But it is increasingly common for information systems and other software to be composed with components from a variety of sources, and with a diversity of licenses. This may result in possible license conflicts and organizational liability for failure to fulfill license obligations. Research and practice to date have not kept up with this sea-change in software licensing arising from free/open source software development. System consumers and users consequently rely on ad hoc heuristics (or costly legal advice) to determine which license rights and obligations are in effect, often with less than optimal results; consulting services are offered to identify unknowing unauthorized use of licensed software in information systems; and researchers have shown how the choice of a (single) specific license for a product affects project success and system adoption. Legal scholars have examined how pairs of software licenses conflict but only in simple contexts. We present an approach for understanding and modeling software licenses, as well as for analyzing conflicts among groups of licenses in realistic system contexts, and for guiding the acquisition, integration, or development of systems with free/open source components in such an environment. This work is based on an empirical analysis of representative software licenses and of heterogeneously-licensed systems. Our approach provides guidance for achieving a “best-of-breed” component strategy while obtaining desired license rights in exchange for acceptable obligations

Thermal Jeans fragmentation within 1000 AU in OMC-1S

We present subarcsecond 1.3 mm continuum ALMA observations towards the Orion Molecular Cloud 1 South (OMC-1S) region, down to a spatial resolution of 74 AU, which reveal a total of 31 continuum sources. We also present subarcsecond 7 mm continuum VLA observations of the same region, which allow to further study fragmentation down to a spatial resolution of 40 AU. By applying a Mean Surface Density of Companions method we find a characteristic spatial scale at ~560 AU, and we use this spatial scale to define the boundary of 19 `cores' in OMC-1S as groupings of millimeter sources. We find an additional characteristic spatial scale at ~2900 AU, which is the typical scale of the filaments in OMC-1S, suggesting a two-level fragmentation process. We measured the fragmentation level within each core and find a higher fragmentation towards the southern filament. In addition, the cores of the southern filament are also the densest (within 1100 AU) cores in OMC-1S. This is fully consistent with previous studies of fragmentation at spatial scales one order of magnitude larger, and suggests that fragmentation down to 40 AU seems to be governed by thermal Jeans processes in OMC-1S.Comment: Accepted to Ap

Social Services in Times of Economic and Social Crisis: The case of Spain

The financial and economic crisis which originated in 2008 has had a severe impact on the population of the Southern European countries. The economic policies of austerity and public deficit control, as well as the neo-liberal and conservative social policies are redefining the public social protection systems, in particular the Social Services. In order to get to understand the current situation, we shall explain how the Social Services were developed in Spain and analyse the causes and consequences of the economic crisis. The working hypothesis is that the greater the increase on the population’s needs, the more developed the Social Services should be. We carried out a descriptive analysis of the situation as far as the social impacts of the crisis per region are concerned. We tested the hypothesis through a parametric model of analysis of variance (one-way ANOVA) triangulating with the non-parametric Kruscal-Wallis test. The working hypothesis failed. The regions with better developed Social Services show a lower level of poverty and social exclusion. The challenges that the public Social Services system faces in times of crisis is three-fold: 1) re-modelling of local administration and transferring of the municipal Social Services responsibilities to the regional administration; 2) an increase of the population at risk of poverty and social exclusion 3) impact on social policies.The research leading to these results has received funding from the European Union Seventh Framework Programme FP7-PEOPLE-2012-IRSES under grant agreement No 318938