Dirac Operators on Coset Spaces

The Dirac operator for a manifold Q, and its chirality operator when Q is even dimensional, have a central role in noncommutative geometry. We systematically develop the theory of this operator when Q=G/H, where G and H are compact connected Lie groups and G is simple. An elementary discussion of the differential geometric and bundle theoretic aspects of G/H, including its projective modules and complex, Kaehler and Riemannian structures, is presented for this purpose. An attractive feature of our approach is that it transparently shows obstructions to spin- and spin_c-structures. When a manifold is spin_c and not spin, U(1) gauge fields have to be introduced in a particular way to define spinors. Likewise, for manifolds like SU(3)/SO(3), which are not even spin_c, we show that SU(2) and higher rank gauge fields have to be introduced to define spinors. This result has potential consequences for string theories if such manifolds occur as D-branes. The spectra and eigenstates of the Dirac operator on spheres S^n=SO(n+1)/SO(n), invariant under SO(n+1), are explicitly found. Aspects of our work overlap with the earlier research of Cahen et al..Comment: section on Riemannian structure improved, references adde

Social media analysis, Twitter and the London Olympics (a research note)

During the course of this paper we examine publically available social media data that relates to the London 2012 Olympic Games that has been harvested and analysed using the Cardiff Online Social Media ObServatory (COSMOS). Social media has matured sufficiently in terms of user uptake and incorporation into traditional media platforms and outlets that the recent London Olympics has been described as the first social media games. For example, the BBC used the Twitter stream to incorporate and mobilise audience participation into its Olympic coverage. With this in mind, this paper will explore the analysis of social media data in relation to sporting events and social media use. In doing so we identify the ways in which COSMOS can be used to identify hashtag popularity over a specific time period to identify real world events, in this case ‘Super Saturday’. The paper reports on indicative evidence that links real-world sporting events to spikes in real time populations’ reaction through self-reported social media updates. In turn, the paper provides an analysis of frequency and sentiment of tweets containing the most popular UK hashtag connected to the London 2012 Olympics over a specified time period. This has consequences for conceptualising the relationship between social actors, events and social media and methodological strategies for understanding the dynamic (locomotive) reactions of populations

Assessing Collaborative, Project-based Learning Models in Introductory Science Courses

Collaborative, project-based learning models have been shown to benefit student learning and engagement in the STEM disciplines. This case study evaluates the use of highly collaborative project- and problem-based learning models in introductory courses in the geosciences and biology. In the geosciences, we developed project-based modules with a strong local focus. Student teams worked on three project-based laboratories dealing with the local geology/geomorphology, water quality of a local stream, and local flooding issues. These replaced traditionally taught laboratories on topographic maps and rivers and streams. Student teams presented project results in lieu of taking a traditional laboratory practical. In biology, we designed a collaborative learning model that incorporated three problem-based learning modules into a first-semester introductory biology course. Students were assigned topics in evolution, cell biology and genetics to research independently during the course of the semester, with each module culminating in a brief presentation on the topic. Modules were designed to mirror concepts being covered in the lecture. Preliminary results suggest that student performance and attitudes towards course material benefitted from this learning model. The authors consider outcomes, benefits, and challenges to students and instructors

Social media analysis, Twitter and the London Olympics (a research note)

During the course of this paper we examine publically available social media data that relates to the London 2012 Olympic Games that has been harvested and analysed using the Cardiff Online Social Media ObServatory (COSMOS). Social media has matured sufficiently in terms of user uptake and incorporation into traditional media platforms and outlets that the recent London Olympics has been described as the first social media games. For example, the BBC used the Twitter stream to incorporate and mobilise audience participation into its Olympic coverage. With this in mind, this paper will explore the analysis of social media data in relation to sporting events and social media use. In doing so we identify the ways in which COSMOS can be used to identify hashtag popularity over a specific time period to identify real world events, in this case ‘Super Saturday’. The paper reports on indicative evidence that links real-world sporting events to spikes in real time populations’ reaction through self-reported social media updates. In turn, the paper provides an analysis of frequency and sentiment of tweets containing the most popular UK hashtag connected to the London 2012 Olympics over a specified time period. This has consequences for conceptualising the relationship between social actors, events and social media and methodological strategies for understanding the dynamic (locomotive) reactions of populations

Policing cyber-neighbourhoods: Tension monitoring and social media networks

We propose that late modern policing practices, that rely on neighbourhood intelligence, the monitoring of tensions, surveillance and policing by accommo- dation, need to be augmented in light of emerging ‘cyber-neighbourhoods’, namely social media networks. The 2011 riots in England were the first to evidence the widespread use of social media platforms to organise and respond to disorder. The police were ill-equipped to make use of the intelligence emerging from these non-terrestrial networks and were found to be at a disadvantage to the more tech-savvy rioters and the general public. In this paper, we outline the development of the ‘tension engine’ component of the Cardiff Online Social Media ObServatroy (COSMOS). This engine affords users with the ability to monitor social media data streams for signs of high tension which can be analysed in order to identify deviations from the ‘norm’ (levels of cohesion/low tension). This analysis can be overlaid onto a palimpsest of curated data, such as official statistics about neighbourhood crime, deprivation and demography, to provide a multidimensional picture of the ‘terrestrial’ and ‘cyber’ streets. As a consequence, this ‘neighbourhood informatics’ enables a means of questioning official constructions of civil unrest through reference to the user-generated accounts of social media and their relationship to other, curated, social and economic data

Effects of antiplatelet therapy on stroke risk by brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases: subgroup analyses of the RESTART randomised, open-label trial

Background Findings from the RESTART trial suggest that starting antiplatelet therapy might reduce the risk of recurrent symptomatic intracerebral haemorrhage compared with avoiding antiplatelet therapy. Brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases (such as cerebral microbleeds) are associated with greater risks of recurrent intracerebral haemorrhage. We did subgroup analyses of the RESTART trial to explore whether these brain imaging features modify the effects of antiplatelet therapy

Stroke risk perception among participants of a stroke awareness campaign

BACKGROUND: Subjective risk factor perception is an important component of the motivation to change unhealthy life styles. While prior studies assessed cardiovascular risk factor knowledge, little is known about determinants of the individual perception of stroke risk. METHODS: Survey by mailed questionnaire among 1483 participants of a prior public stroke campaign in Germany. Participants had been informed about their individual stroke risk based on the Framingham stroke risk score. Stroke risk factor knowledge, perception of lifetime stroke risk and risk factor status were included in the questionnaire, and the determinants of good risk factor knowledge and high stroke risk perception were identified using logistic regression models. RESULTS: Overall stroke risk factor knowledge was good with 67–96% of the participants recognizing established risk factors. The two exceptions were diabetes (recognized by 49%) and myocardial infarction (57%). Knowledge of a specific factor was superior among those affected by it. 13% of all participants considered themselves of having a high stroke risk, 55% indicated a moderate risk. All major risk factors contributed significantly to the perception of being at high stroke risk, but the effects of age, sex and education were non-significant. Poor self-rated health was additionally associated with high individual stroke risk perception. CONCLUSION: Stroke risk factor knowledge was high in this study. The self perception of an increased stroke risk was associated with established risk factors as well as low perception of general health

The effect of alternative methods of cardiopulmonary resuscitation — Cough CPR, percussion pacing or precordial thump — on outcomes following cardiac arrest. A systematic review

Background Cardiopulmonary resuscitation (CPR) improves cardiac arrest survival. Cough CPR, percussion pacing and precordial thump have been reported as alternative CPR techniques. We aimed to summarise in a systematic review the effectiveness of these alternative CPR techniques. Methods We searched Ovid MEDLINE, EMBASE and the Cochrane Library on 24/08/2020. We included randomised controlled trials, observational studies and case series with five or more patients. Two reviewers independently reviewed title and abstracts to identify studies for full-text review, and reviewed bibliographies and ‘related articles’ (using PubMed) of full-texts for further eligible studies. We extracted data and performed risk-of-bias assessments on studies included in the systematic review. We summarised data in a narrative synthesis, and used GRADE to assess evidence certainty. Results We included 23 studies (cough CPR n = 4, percussion pacing n = 4, precordial thump n = 16; one study studied two interventions). Only two (both precordial thump) had a comparator group (‘standard’ CPR). For all techniques evidence certainty was very low. Available evidence suggests that precordial thump does not improve survival to hospital discharge in out-of-hospital cardiac arrest. The review did not find evidence that cough CPR or percussion pacing improve clinical outcomes following cardiac arrest. Conclusion Cough CPR, percussion pacing and precordial thump should not be routinely used in established cardiac arrest. In specific inpatient, monitored settings cough CPR (in conscious patients) or percussion pacing may be attempted at the onset of a potential lethal arrhythmia. These must not delay standard CPR efforts in those who lose cardiac output

The RRM domain of poly(A)-specific ribonuclease has a noncanonical binding site for mRNA cap analog recognition

The degradation of the poly(A) tail is crucial for posttranscriptional gene regulation and for quality control of mRNA. Poly(A)-specific ribonuclease (PARN) is one of the major mammalian 3′ specific exo-ribonucleases involved in the degradation of the mRNA poly(A) tail, and it is also involved in the regulation of translation in early embryonic development. The interaction between PARN and the m7GpppG cap of mRNA plays a key role in stimulating the rate of deadenylation. Here we report the solution structures of the cap-binding domain of mouse PARN with and without the m7GpppG cap analog. The structure of the cap-binding domain adopts the RNA recognition motif (RRM) with a characteristic α-helical extension at its C-terminus, which covers the β-sheet surface (hereafter referred to as PARN RRM). In the complex structure of PARN RRM with the cap analog, the base of the N7-methyl guanosine (m7G) of the cap analog stacks with the solvent-exposed aromatic side chain of the distinctive tryptophan residue 468, located at the C-terminal end of the second β-strand. These unique structural features in PARN RRM reveal a novel cap-binding mode, which is distinct from the nucleotide recognition mode of the canonical RRM domains