A tale of two scholarly blog platforms: comparing and conceptualizing online research communities.

Cornelius Puschmann and Marco Bastos expand on the computational methods employed to understand the contributions and online networks of two prominent scholarly blog platforms, HASTAC and Hypotheses. Their analysis suggests one community is driven more by an emphasis on the new media movement and cross-disciplinary aspiration, compared to the other’s more traditional disciplinary approach with a focus on the new publishing environment. The toolbox for analyzing blog platforms is still evolving and any results need to be treated with care. But it is clear that these computational methods can shed a new light on ongoing developments in science and scholarship

Comparison of Algorithms for Baseline Correction of LIBS Spectra for Quantifying Total Carbon in Brazilian Soils

LIBS is a promising and versatile technique for multi-element analysis that usually takes less than a minute and requires minimal sample preparation and no reagents. Despite the recent advances in elemental quantification, the LIBS still faces issues regarding the baseline produced by background radiation, which adds non-linear interference to the emission lines. In order to create a calibration model to quantify elements using LIBS spectra, the baseline has to be properly corrected. In this paper, we compared the performance of three filters to remove random noise and five methods to correct the baseline of LIBS spectra for the quantification of total carbon in soil samples. All combinations of filters and methods were tested, and their parameters were optimized to result in the best correlation between the corrected spectra and the carbon content in a training sample set. Then all combinations with the optimized parameters were compared with a separate test sample set. A combination of Savitzky-Golay filter and 4S Peak Filling method resulted in the best correction: Pearson's correlation coefficient of 0.93 with root mean square error of 0.21. The result was better than using a linear regression model with the carbon emission line 193.04 nm (correlation of 0.91 with error of 0.26). The procedure proposed here opens a new possibility to correct the baseline of LIBS spectra and to create multivariate methods based on the a given spectral range.Comment: 13 pages, 5 figure

The spectral sign: a cybernetic perspective on digital conversations

This paper discusses the idea of a spectral sign in relation to the concept of multilogue (Shank 1993) and crosstalk (Crystal 2001), a discussion largely based upon linguistic and semiotic contexts. In short, spectral sign is the outcome of an operation that corrupts the semiotic structure of a sign, replacing instead of adding units of meaning. From a linguistic point of view, the spectral sign relies on the effects of communication technologies that challenge the dyadic representation of a sign. Instead of relating to another sign to perform a paired circle, spectral sign connects a diversity of circles that are not immediately accessible in a semiotic context. From a cybernetic point of view, this interplay represents negative feedback between observer and observed and reveals digital meaning as being simultaneously two: one related to the source, and the other to the receiver

Tents, tweets, and events: The interplay between ongoing protests and social media

Recent protests have fuelled deliberations about the extent to which social media ignites popular uprisings. In this article, we use time-series data of Twitter, Facebook, and onsite protests to assess the Granger causality between social media streams and onsite developments at the Indignados, Occupy, and Brazilian Vinegar protests. After applying Gaussianization to the data, we found contentious communication on Twitter and Facebook forecasted onsite protest during the Indignados and Occupy protests, with bidirectional Granger causality between online and onsite protest in the Occupy series. Conversely, the Vinegar demonstrations presented Granger causality between Facebook and Twitter communication, and separately between protestors and injuries/arrests onsite. We conclude that the effective forecasting of protest activity likely varies across different instances of political unrest

Cor/raça e desigualdades em saúde bucal entre adolescentes brasileiros

This study assessed oral health outcomes (perceived dental treatment need, untreated dental caries, gingival bleeding, periodontal pockets, and pain in teeth and gums), in relation to color/race inequalities among adolescents in each Brazilian region. The database included dental examination and interview of 16,833 15-19-year-old adolescents, surveyed by the Brazilian health authority, from May 2002 to October 2003, in accordance with international diagnostic criteria standardized by the World Health Organization. Prevalence ratios estimated by Poisson regression, and controlled by socioeconomic status and access to fluoridated piped water, assessed oral health differentials among color/race groups and country's regions. Except for periodontal pockets, prevalence figures were higher in the North and Northeast: perceived dental treatment needs, untreated dental caries, gingival bleeding at probing and pain in teeth and gums varied between 80-83%, 75-76%, 38-43%, and 17-18%, respectively, in these regions. Adolescents living in the Southeast - the richest Brazilian region - presented a better general profile of oral health than their counterparts living in the remaining regions; they had a lower prevalence of untreated dental caries (54%) and unfavorable gingival status (29%). However, the Southeast presented color/race inequalities in all oral health outcomes, with a poorer profile systematically affecting browns or blacks, depending on the oral health condition under consideration. These results reinforce the need for expanding the amplitude of health initiatives aimed at adolescent oral health. Socially appropriate health programs should concurrently aim at the reduction of levels of oral disease and its inequalities.O presente estudo avaliou desfechos de saúde bucal (necessidade de tratamento dentário autopercebida, cárie dentária não tratada, sangramento gengival, bolsa periodontal e dor nos dentes e gengivas) com o intuito de identificar desigualdades por cor/raça entre adolescentes em cada uma das macro-regiões brasileiras. O banco de dados incluiu informações sociodemográficas e de exames bucais de 16.833 adolescentes entre 15-19 anos de idade, investigados pelo Ministério de Saúde entre maio de 2002 e outubro de 2003, conforme critérios diagnósticos preconizados pela Organização Mundial da Saúde. Foram utilizadas razões de prevalência, calculadas por regressão de Poisson e ajustadas para variáveis socioeconômicas e acesso a água fluoretada, para estimar desigualdades nos desfechos de saúde bucal entre os grupos de cor/raça e as macro-regiões brasileiras. Exceto para bolsa periodontal, as estimativas de prevalência foram mais altas no Norte e no Nordeste: necessidade de tratamento dentário autopercebida, cárie dentária não tratada, sangramento gengival e dor nos dentes e gengivas variaram entre 80-83%, 75-76%, 38-43% e 17-18%, respectivamente, nestas regiões. Os adolescentes do Sudeste - a macro-região mais rica do país - apresentaram, em geral, melhores condições de saúde bucal, quando comparados com seus pares das demais macro-regiões; os adolescentes do Sudeste apresentaram menores prevalências de cárie dentária não tratada (54%) e de sangramento gengival (29%). Entretanto, o Sudeste demonstrou desigualdades por cor/raça em todos os desfechos investigados, com piores condições afetando sistematicamente pardos ou pretos, a depender da condição de saúde bucal investigada. Estes resultados reforçam a necessidade de expandir as ações dirigidas à saúde bucal dos adolescentes brasileiros. Programas/intervenções em saúde socialmente sensíveis devem visar a redução de níveis de morbidades bucais, bem como de suas desigualdades.(CNPq) Brazilian Council for Scientific and Technological Developmen

Tuning the pseudospin polarization of graphene by a pseudo-magnetic field

One of the intriguing characteristics of honeycomb lattices is the appearance of a pseudo-magnetic field as a result of mechanical deformation. In the case of graphene, the Landau quantization resulting from this pseudo-magnetic field has been measured using scanning tunneling microscopy. Here we show that a signature of the pseudo-magnetic field is a local sublattice symmetry breaking observable as a redistribution of the local density of states. This can be interpreted as a polarization of graphene's pseudospin due to a strain induced pseudo-magnetic field, in analogy to the alignment of a real spin in a magnetic field. We reveal this sublattice symmetry breaking by tunably straining graphene using the tip of a scanning tunneling microscope. The tip locally lifts the graphene membrane from a SiO$_2$ support, as visible by an increased slope of the $I(z)$ curves. The amount of lifting is consistent with molecular dynamics calculations, which reveal a deformed graphene area under the tip in the shape of a Gaussian. The pseudo-magnetic field induced by the deformation becomes visible as a sublattice symmetry breaking which scales with the lifting height of the strained deformation and therefore with the pseudo-magnetic field strength. Its magnitude is quantitatively reproduced by analytic and tight-binding models, revealing fields of 1000 T. These results might be the starting point for an effective THz valley filter, as a basic element of valleytronics.Comment: Revised manuscript: streamlined the abstract and introduction, added methods to supplement, Nano Letters, 201

HIPK2 and extrachromosomal histone H2B are separately recruited by Aurora-B for cytokinesis

Cytokinesis, the final phase of cell division, is necessary to form two distinct daughter cells with correct distribution of genomic and cytoplasmic materials. Its failure provokes genetically unstable states, such as tetraploidization and polyploidization, which can contribute to tumorigenesis. Aurora-B kinase controls multiple cytokinetic events, from chromosome condensation to abscission when the midbody is severed. We have previously shown that HIPK2, a kinase involved in DNA damage response and development, localizes at the midbody and contributes to abscission by phosphorylating extrachromosomal histone H2B at Ser14. Of relevance, HIPK2-defective cells do not phosphorylate H2B and do not successfully complete cytokinesis leading to accumulation of binucleated cells, chromosomal instability, and increased tumorigenicity. However, how HIPK2 and H2B are recruited to the midbody during cytokinesis is still unknown. Here, we show that regardless of their direct (H2B) and indirect (HIPK2) binding of chromosomal DNA, both H2B and HIPK2 localize at the midbody independently of nucleic acids. Instead, by using mitotic kinase-specific inhibitors in a spatio-temporal regulated manner, we found that Aurora-B kinase activity is required to recruit both HIPK2 and H2B to the midbody. Molecular characterization showed that Aurora-B directly binds and phosphorylates H2B at Ser32 while indirectly recruits HIPK2 through the central spindle components MgcRacGAP and PRC1. Thus, among different cytokinetic functions, Aurora-B separately recruits HIPK2 and H2B to the midbody and these activities contribute to faithful cytokinesis

Remielinização em camundongos Knockout para conexina 32 desmielinizados experimentalmente

Este estudo visou avaliar o papel da conexina 32 (Cx 32) durante a remielinização no sistema nervoso periférico. Uma injeção local de 0,1% de solução de brometo de etídio foi realizada no nervo ciático de camundongos deletados para a Cx 32, com eutanásia dos animais aos 1, 2, 3, 7, 15, 21 e 30 dias pós-injeção. Avaliações histoquímicas, imunoistoquímicas, por imunofluorescência e por microscopia eletrônica de transmissão foram utilizadas na análise do desenvolvimento das lesões. Nos nervos ciáticos, células de Schwann mostraram inicialmente sinais de intoxicação e rejeitaram suas bainhas. Após sete dias, observaram-se finas bainhas neoformadas, com compactação desigual e alças redundantes (tomácula). Conclui-se que a regeneração de bainhas de mielina perdidas no SNP seguiu o padrão já relatado deste modelo em outras espécies de laboratório. Portanto, estes resultados sugerem que a ausência da Cx 32 não interferiu com o padrão normal de remielinização em camundongos jovens neste modeloThe aim of this study was to evaluate the role of connexin 32 (Cx 32) during remyelination of the peripheral nervous system, through a local injection of either 0,1% ethidium bromide solution or saline in the sciatic nerve of Cx 32 knockout mice. Euthanasia was performed ranging from 1, 2, 3, 7, 15, 21 to 30 days after injection. Histochemical, immunohistochemical, immunofluorescence and transmission electron microscopical techniques were used to analyze the development of the lesions. Within the sciatic nerves, Schwann cells initially showed signs of intoxication and rejected their sheaths; after seven days, some thin newly formed myelin sheaths with uneven compactness and redundant loops (tomacula) were conspicuous. We concluded that the regeneration of lost myelin sheaths within the PNS followed the pattern already reported for this model in other laboratory species. Therefore, these results suggest that absence of Cx 32 did not interfere with the normal pattern of remyelination in this model in young miceCNPq 475029/2004-6Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES

Parametrizing Brexit: Mapping Twitter Political Space to Parliamentary Constituencies

In this paper, a proof of concept study is performed to validate the use of social media signal to model the ideological coordinates underpinning the Brexit debate . We rely on geographically - en rich ed Twitter data and a purpose - built , deep learning algorithm to map the political value space of users tweeting the referendum onto Parliamentary Constituencies. We find a significant incidence of nationalist sentiments and economic views expressed on Twitter , which pers ist throughout the campaign and are only offset in the last days when a globalist upsurge brings the British Twittersphere closer to a divide between nationalis t and globalis t standpoints . Upon combining demographic variables with the classifier scores , we f i nd that the model explains 41% of the variance in the referendum vote, an indi cation that not only material inequality, but also ideological readjustments have contributed to the outcome of the referendum . We conclude with a discussion of conceptual and methodological challenges in signal - processing social media data as a source for the measurement of public opinion