Detection and fine-grained classification of cyberbullying events

In the current era of online interactions, both positive and negative experiences are abundant on the Web. As in real life, negative experiences can have a serious impact on youngsters. Recent studies have reported cybervictimization rates among teenagers that vary between 20% and 40%. In this paper, we focus on cyberbullying as a particular form of cybervictimization and explore its automatic detection and fine-grained classification. Data containing cyberbullying was collected from the social networking site Ask.fm. We developed and applied a new scheme for cyberbullying annotation, which describes the presence and severity of cyberbullying, a post author's role (harasser, victim or bystander) and a number of fine-grained categories related to cyberbullying, such as insults and threats. We present experimental results on the automatic detection of cyberbullying and explore the feasibility of detecting the more fine-grained cyberbullying categories in online posts. For the first task, an F-score of 55.39% is obtained. We observe that the detection of the fine-grained categories (e.g. threats) is more challenging, presumably due to data sparsity, and because they are often expressed in a subtle and implicit way

Automatic characterization of neointimal tissue by intravascular optical coherence tomography

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Long-term outcomes after percutaneous revascularization of complex coronary bifurcation lesions using a dedicated self-expanding biolimus-eluting stent system

Background: To evaluate long-term clinical outcomes after treatment of complex bifurcation lesions with the AXXESS dedicated self-expanding biolimus A9-eluting bifurcation stent.Methods: Between 2004 and 2013, 123 patients with complex bifurcation lesions were treated in a single-center with the AXXESS stent in the proximal main vessel (MV) and additional drug-eluting stents in branches when required. Median follow-up was 5 years. Primary endpoint was the rate of major adverse cardiac events (MACE). Secondary endpoints included MACE components (cardiac death, non-periprocedural clinical myocardial infarction [MI], target lesion revascularization [TLR] and definite/probable stent thrombosis [ST]) as well as all-cause death, target vessel revascularization (TVR) and non-TVR.Results: During follow-up, 11 (8.9%) patients experienced a MACE, of whom 2 (1.6%) suffered cardiac death, 2 (1.6%) had a non-periprocedural clinical MI requiring TLR, and 7 (5.7%) underwent elective TLR. No definite/probable ST was observed. All-cause death occurred in 9 (7.3%) patients, TVR in 11 (8.9%) and non-TVR in 11 (8.9%). Patients treated for left main (LM) bifurcation lesions were more likely to experience MACE than non-LM bifurcation lesions (25% vs. 6.5%, p = 0.04).Conclusions: Percutaneous revascularization of complex bifurcation lesions with the AXXESS stent is safe and provides excellent long-term results, especially in non-LM lesions

Automatic detection and prevention of cyberbullying

The recent development of social media poses new challenges to the research community in analyzing online interactions between people. Social networking sites offer great opportunities for connecting with others, but also increase the vulnerability of young people to undesirable phenomena, such as cybervictimization. Recent research reports that on average, 20% to 40% of all teenagers have been victimized online. In this paper, we focus on cyberbullying as a particular form of cybervictimization. Successful prevention depends on the adequate detection of potentially harmful messages. However, given the massive information overload on the Web, there is a need for intelligent systems to identify potential risks automatically. We present the construction and annotation of a corpus of Dutch social media posts annotated with fine-grained cyberbullying-related text categories, such as insults and threats. Also, the specific participants (harasser, victim or bystander) in a cyberbullying conversation are identified to enhance the analysis of human interactions involving cyberbullying. Apart from describing our dataset construction and annotation, we present proof-of-concept experiments on the automatic identification of cyberbullying events and fine-grained cyberbullying categories

Current Limitations in Cyberbullying Detection: on Evaluation Criteria, Reproducibility, and Data Scarcity

The detection of online cyberbullying has seen an increase in societal importance, popularity in research, and available open data. Nevertheless, while computational power and affordability of resources continue to increase, the access restrictions on high-quality data limit the applicability of state-of-the-art techniques. Consequently, much of the recent research uses small, heterogeneous datasets, without a thorough evaluation of applicability. In this paper, we further illustrate these issues, as we (i) evaluate many publicly available resources for this task and demonstrate difficulties with data collection. These predominantly yield small datasets that fail to capture the required complex social dynamics and impede direct comparison of progress. We (ii) conduct an extensive set of experiments that indicate a general lack of cross-domain generalization of classifiers trained on these sources, and openly provide this framework to replicate and extend our evaluation criteria. Finally, we (iii) present an effective crowdsourcing method: simulating real-life bullying scenarios in a lab setting generates plausible data that can be effectively used to enrich real data. This largely circumvents the restrictions on data that can be collected, and increases classifier performance. We believe these contributions can aid in improving the empirical practices of future research in the field

Relationship between location and size of myocardial infarction and their reciprocal influences on post-infarction left ventricular remodeling

AimsTo assess the intricate relationship between myocardial infarction (MI) location and size and their reciprocal influences on post-infarction left ventricular (LV) remodelling.Methods and resultsA cohort of 260 reperfused ST-segment elevation MI patients was prospectively studied with cardiovascular magnetic resonance at 1 week (baseline) and 4 months (follow-up). Area at risk (AAR) and MI size were quantified by T2-weighted and late-gadolinium enhancement imaging, respectively. Adverse LV remodelling was defined as an increase in LV end-systolic volume ≥15 at follow-up. One hundred and twenty-seven (49) patients had anterior MI and 133 (51) patients had non-anterior MI. Although the degree of myocardial salvage was similar between groups (P=0.74), anterior MI patients had larger AAR and MI size than non-anterior MI patients yielding worse regional and global LV function at baseline and follow-up. At univariable analysis, anterior MI was associated with increased risk of adverse LV remodelling (P=0.017) and lower LV ejection fraction (EF) at follow-up (P=0.001), but not when accounted for baseline MI size. Accordingly, at multivariable analysis, baseline MI size but not its location was an independent predictor of adverse LV remodelling (odds ratio 1.061, P < 0.001) and EF at follow-up (β-coefficient=-0.255, P < 0.001).ConclusionAnterior MI patients experience more pronounced post-infarction LV remodelling and dysfunction than non-anterior MI patients due to a greater magnitude of irreversible ischaemic LV damage without any independent contribution of MI location. © 2011 The Author

CoRoT photometry and high-resolution spectroscopy of the interacting eclipsing binary AU Mon

Analyses of very accurate CoRoT space photometry, past Johnson V photoelectric photometry and high-resolution \'echelle spectra led to the determination of improved and consistent fundamental stellar properties of both components of AU Mon. We derived new, accurate ephemerides for both the orbital motion (with a period of 11.113d) and the long-term, overall brightness variation (with a period of 416.9d) of this strongly interacting Be + G semi-detached binary. It is shown that this long-term variation must be due to attenuation of the total light by some variable circumbinary material. We derived the binary mass ratio $M_{\rm G}/M_{\rm B}$ = 0.17\p0.03 based on the assumption that the G-type secondary fills its Roche lobe and rotates synchronously. Using this value of the mass ratio as well as the radial velocities of the G-star, we obtained a consistent light curve model and improved estimates of the stellar masses, radii, luminosities and effective temperatures. We demonstrate that the observed lines of the B-type primary may not be of photospheric origin. We also discover rapid and periodic light changes visible in the high-quality residual CoRoT light curves. AU Mon is put into perspective by a comparison with known binaries exhibiting long-term cyclic light changes.Comment: Accepted for publication in MNRA

The role of stakeholder involvement in the evolving EU HTA process:Insights generated through the European Access Academy’s multi-stakeholder pre-convention questionnaire

Involvement of all relevant stakeholders will be of utmost importance for the success of the developing EU HTA harmonization process. A multi-step procedure was applied to develop a survey across stakeholders/collaborators within the EU HTA framework to assess their current level of involvement, determine their suggested future role, identify challenges to contribution, and highlight efficient ways to fulfilling their role. The ‘key’ stakeholder groups identified and covered by this research included: patients‘, clinicians‘, regulatory, and Health Technology Developer representatives. The survey was circulated to a wide expert audience including all relevant stakeholder groups in order to determine self-perception by the ‘key’ stakeholders regarding involvement in the HTA process (self-rating), and in a second, slightly modified version of the questionnaire, to determine the perception of ‘key’ stakeholder involvement by HTA bodies, payers, and policymakers (external rating). Predefined analyses were conducted on the submitted responses. Fifty-four responses were received (patients 9; clinicians: 8; regulators: 4; HTDs 14; HTA bodies: 7; Payers: 5; policymakers 3; others 4). The mean self-perceived involvement score was consistently lower for each of the ‘key’ stakeholder groups than the respective external ratings. Based on the qualitative insights generated in the survey, a RACI Chart (Responsible/Accountable/Consulted/Informed) was developed for each of the stakeholder groups to determine their roles and involvement in the current EU HTA process. Our findings suggest extensive effort and a distinct research agenda are required to ensure adequate involvement of the key stakeholder groups in the evolving EU HTA process.</p