Using correlation matrix memories for inferencing in expert systems

Outline of The Chapter… Section 16.2 describes CMM and the Dynamic Variable Binding Problem. Section 16.3 deals with how CMM is used as part of an inferencing engine. Section 16.4 details the important performance characteristics of CMM

Popular with the Robots: Accusation and Automation in the Argentine Presidential Elections, 2015

Accusations of dishonourable campaigning have featured in every Argentine presidential election since the return to democracy in 1983. Yet, allegations made in the elections this October and November looked different from earlier ones. The campaign team for the centre-leftist candidate Daniel Scioli argued that Cambiemos, the centre-right coalition led by Mauricio Macri, was abusing the political affordances of social media by running a Twitter campaign via ‘50,000’ fake accounts. This paper presents evidence suggesting that both teams promoted their campaigns through automation on Twitter. Although the Macri campaign was subtler, both teams appear to have used automation to the same end: maximizing the diffusion of party content and creating an inflated image of their popularity. Neither team attempted to muffle or engage with opposing voices through automation. We argue that in a political culture fixated on the appearance of popularity, the use of automation to simulate mass support appears an organic development as campaigning enters the still unregulated Twittersphere. We compare our findings to the uses of automation in the Russian Twittersphere and conclude that there may be greater variation in the political usage of Twitter between political contexts than between different types of political event occurring in the same country.This study was funded by the Leverhulme Trust (grant number RP2012-C-017).This is the final version of the article. It first appeared from Springer via http://dx.doi.org/10.1007/s10767-016-9233-

Race, Deindustrialization, and Homicide: Exploring the Relationship between Deindustrialization and Racial Homicide Victimization

Deindustrialization is an important economic phenomenon affecting present day crime, in particular homicide victimization rates. Previous research has found that deindustrialization has several different effects, including increasing the income inequality and labor instability of a community. These effects also varied among racial groups. This study hypothesizes that deindustrialization effects would increase homicide rates and have a greater effect on black homicide victimization than any other rate. Drawing on a sample of 161 large cities, the direct and indirect effects of deindustrialization were estimated in multivariate regression analyses. The analyses found the opposite effect of what was hypothesized, that white victimization rates were affected directly by deindustrialization while black and total victimizations were not

Sparking debate? Political deaths and Twitter discourses in Argentina and Russia

The big question that pervades debate between techno-optimists and their detractors is whether social media are good for democracy. Do they help to produce or accelerate democratic change or, alternatively, might they hinder it? This article foregrounds an alternative perspective, arguing that individual social networking applications likely do not fulfil a single political function across national contexts. Their functionality may be mediated instead by language and by pre-existing relationships between the state and offline domestic media. We arrive at this conclusion through examining reactions on Twitter to two fatal events that occurred in early 2015: the death in suspicious and politically charged circumstances of the special prosecutor Alberto Nisman in Argentina, and the murder in Russia of opposition activist Boris Nemtsov. Several similarities between the two deaths facilitate a comparative analysis of the discourses around them in the Spanish-language and Russian-language Twitter spheres respectively. In Russia, a hostile social media environment polluted by high levels of automated content and other spam reduced the utility of Twitter for opposition voices working against an increasingly authoritarian state. In Argentina, a third-wave democracy, Twitter discourses appeared as predominantly coextensive with other pro-government and opposition online, print, and broadcast fora, thus consolidating and amplifying a highly polarized and repetitive wider public political conversation. Despite the potential for social media to help citizens circumvent restrictions to discursive participation in national public spheres, in both cases compared here language environment and domestic political structures contribute significantly to determining the uses and limitations of online spaces for expressing opinion on current affairs stories involving the state.This is the author accepted manuscript. The final version is available from Taylor & Francis via http://dx.doi.org/10.1080/1369118X.2016.114080

The relationship between Higher Education and labour market in Greece : the weakest link?

The high level of graduate unemployment, even though it is acknowledged as one of the most distinctive characteristics of the Greek labour market, it has not attracted enough attention in the academic literature. This paper utilizes micro-data from the Labour Force Survey in order to investigate how the employment situation of young (aged 35 and below) graduates varies across fields of study. The findings suggest that graduates of disciplines that have high levels of private sector employment, such as Polytechnics and Computer Science, are in general better off in the Greek labour market. On the other hand, graduates of disciplines that are traditionally related to the needs of the public sector, such as Sociology and Humanities, face poor employment prospects. The findings of this study highlight the need for drastic reforms of the Higher Education system

Partial inhibition of RNA polymerase I promotes animal health and longevity

Health and survival in old age can be improved by changes in gene expression. RNA polymerase (Pol) I is the essential, conserved enzyme whose task is to generate the pre-ribosomal RNA (rRNA). We find that reducing the levels of Pol I activity is sufficient to extend lifespan in the fruit fly. This effect can be recapitulated by partial, adult-restricted inhibition, with both enterocytes and stem cells of the adult midgut emerging as important cell types. In stem cells, Pol I appears to act in the same longevity pathway as Pol III, implicating rRNA synthesis in these cells as the key lifespan determinant. Importantly, reduction in Pol I activity delays broad, age-related impairment and pathology, improving the function of diverse organ systems. Hence, our study shows that Pol I activity in the adult drives systemic, age-related decline in animal health and anticipates mortality

Projected tt-SNE for batch correction

Biomedical research often produces high-dimensional data confounded by batch effects such as systematic experimental variations, different protocols and subject identifiers. Without proper correction, low-dimensional representation of high-dimensional data might encode and reproduce the same systematic variations observed in the original data, and compromise the interpretation of the results. In this article, we propose a novel procedure to remove batch effects from low-dimensional embeddings obtained with t-SNE dimensionality reduction. The proposed methods are based on linear algebra and constrained optimization, leading to efficient algorithms and fast computation in many high-dimensional settings. Results on artificial single-cell transcription profiling data show that the proposed procedure successfully removes multiple batch effects from t-SNE embeddings, while retaining fundamental information on cell types. When applied to single-cell gene expression data to investigate mouse medulloblastoma, the proposed method successfully removes batches related with mice identifiers and the date of the experiment, while preserving clusters of oligodendrocytes, astrocytes, and endothelial cells and microglia, which are expected to lie in the stroma within or adjacent to the tumors.Comment: 16 pages, 3 figure