Fake News Detection on Twitter Using Propagation Structures

The growth of social media has revolutionized the way people access information. Although platforms like Facebook and Twitter allow for a quicker, wider and less restricted access to information, they also consist of a breeding ground for the dissemination of fake news. Most of the existing literature on fake news detection on social media proposes user-based or content-based approaches. However, recent research revealed that real and fake news also propagate significantly differently on Twitter. Nonetheless, only a few articles so far have explored the use of propagation features in their detection. Additionally, most of them have based their analysis on a narrow tweet retrieval methodology that only considers tweets to be propagating a news piece if they explicitly contain an URL link to an online news article. By basing our analysis on a broader tweet retrieval methodology that also allows tweets without an URL link to be considered as propagating a news piece, we contribute to fill this research gap and further confirm the potential of using propagation features to detect fake news on Twitter. We firstly show that real news are significantly bigger in size, are spread by users with more followers and less followings, and are actively spread on Twitter for a longer period of time than fake news. Secondly, we achieve an 87% accuracy using a Random Forest Classifier solely trained on propagation features. Lastly, we design a Geometric Deep Learning approach to the problem by building a graph neural network that directly learns on the propagation graphs and achieve an accuracy of 73.3%

Association of ambient particulate matter with heart failure incidence and all-cause readmissions in Tasmania: an observational study

Objectives: We sought to investigate the relationship between air quality and heart failure (HF) incidence and rehospitalisation to elucidate whether there is a threshold in this relationship and whether this relationship differs for HF incidence and rehospitalisation.Methods: This retrospective observational study was performed in an Australian state-wide setting, where air pollution is mainly associated with wood-burning for winter heating. Data included all 1246 patients with a first-ever HF hospitalisation and their 3011 subsequent all-cause readmissions during 2009-2012. Daily particulate matter 2.5), temperature, relative humidity and influenza infection were recorded. Poisson regression was used, with adjustment for time trend, public and school holiday and day of week.Results: Tasmania has excellent air quality (median PM2.5=2.9 µg/m3 (IQR: 1.8-6.0)). Greater HF incidences and readmissions occurred in winter than in other seasons (p2.5 was detrimentally associated with HF incidence (risk ratio (RR)=1.29 (1.15-1.42)) and weakly so with readmission (RR=1.07 (1.02-1.17)), with 1 day time lag. In multivariable analyses, PM2.5 significantly predicted HF incidence (RR=1.12 (1.01-1.24)) but not readmission (RR=0.96 (0.89-1.04)). HF incidence was similarly low when PM 3 and only started to rise when PM2.5≥4 µg/m3. Stratified analyses showed that PM2.5 was associated with readmissions among patients not taking beta-blockers but not among those taking beta-blockers (pinteraction=0.011).Conclusions: PM2.5 predicted HF incidence, independent of other environmental factors. A possible threshold of PM2.5=4 µg/m3 is far below the daily Australian national standard of 25 µg/m3. Our data suggest that beta-blockers might play a role in preventing adverse association between air pollution and patients with HF

Nrf2 deficiency influences susceptibility to steroid resistance via HDAC2 reduction

Abnormal lung inflammation and oxidant burden are associated with a significant reduction in histone deacetylase 2 (HDAC2) abundance and steroid resistance. We hypothesized that Nrf2 regulates steroid sensitivity via HDAC2 in response to inflammation in mouse lung. Furthermore, HDAC2 deficiency leads to steroid resistance in attenuating lung inflammatory response, which may be due to oxidant/antioxidant imbalance. Loss of antioxidant transcription factor Nrf2 resulted in decreased HDAC2 in lung, and increased inflammatory lung response which was not reversed by steroid. Thus, steroid resistance or inability of steroids to control lung inflammatory response is dependent on Nrf2-HDAC2 axis. These findings have implications in steroid resistance, particularly during the conditions of oxidative stress when the lungs are more susceptible to inflammatory response, which is seen in patients with chronic obstructive pulmonary disease, asthma, rheumatoid arthritis, and inflammatory bowel disease

Engaging with History after Macpherson

The Race Relations Amendment Act (2000) identifies a key role for education, and more specifically history, in promoting ‘race equality’ in Britain. In this article Ian Grosvenor and Kevin Myers consider the extent of young people’s current engagement with the history of ‘diversity, change and immigration’ which underpins the commitment to ‘race equality’. Finding that in many of Britain’s schools and universities a singular and exclusionary version of history continues to dominate the curriculum, they go on to consider the reasons for the neglect of multiculturalism. The authors identify the development of an aggressive national identity that depends on the past for its legitimacy and argue that this sense of the past is an important obstacle to future progress

Distribution and origin of suspended matter and organic carbon pools in the Tana River Basin, Kenya

We studied patterns in organic carbon pools and their origin in the Tana River Basin (Kenya), in February 2008 (dry season), September–November 2009 (wet season), and June–July 2010 (end of wet season), covering the full continuum from headwater streams to lowland mainstream sites. A consistent downstream increase in total suspended matter (TSM, 0.6 to 7058 mg l−1) and particulate organic carbon (POC, 0.23 to 119.8 mg l−1) was observed during all three sampling campaigns, particularly pronounced below 1000m above sea level, indicating that most particulate matter exported towards the coastal zone originated from the mid and low altitude zones rather than from headwater regions. This indicates that the cascade of hydroelectrical reservoirs act as an extremely efficient particle trap. Although 7Be / 210Pbxs ratios/age of suspended sediment do not show clear seasonal variation, the gradual downstream increase of suspended matter during end of wet season suggests its origin is caused by inputs of older sediments from bank erosion and/or river sediment resuspension. During wet season, higher TSM concentrations correspond with relatively young suspended matter, suggesting a contribution from recently eroded material.With the exception of reservoir waters, POC was predominantly of terrestrial origin as indicated by generally high POC : chlorophyll a (POC : Chl a) ratios (up to 41 000). Stable isotope signatures of POC ( 13CPOC) ranged between −32 and −20‰and increased downstream, reflecting an increasing contribution of C4-derived carbon in combination with an expected shift in 13C for C3 vegetation towards the more semi-arid lowlands. 13C values in sediments from the main reservoir (−19.5 to −15.7 ‰) were higher than those found in any of the riverine samples, indicating selective retention of particles associated with C4 fraction. Dissolved organic carbon (DOC) concentrations were highest during the end of wet season (2.1 to 6.9 mg l−1), with stable isotope signatures generally between −28 and −22 ‰. A consistent downstream decrease in % organic carbon (%OC) was observed for soils, riverine sediments, and suspended matter. This was likely due to better preservation of the organic fraction in colder high altitude regions, with loss of carbon during downstream spiraling. 13C values for soil and sediment did not exhibit clear altitudinal patterns, but values reflect the full spectrum from C3-dominated to C4-dominated sites. Very low ratios of organic carbon to mineral surface area (OC : SA) were found in reservoir sediments and suspended matter in the lower Tana River, indicating that these are stable OC pools which have undergone extensive degradation. Overall, our study demonstrates that substantial differences occur in both the quantities and origin of suspended sediments and organic carbon along the river profile in this tropical river basin, as well as seasonal differences in the mechanisms causing such variations.Peer reviewe

Cigarette Smoke Exposure Alters mSin3a and Mi-2α/β Expression; implications in the control of pro-inflammatory gene transcription and glucocorticoid function

<p>Abstract</p> <p>Background</p> <p>The key co-repressor complex components HDAC-2, Mi-2α/β and mSin3a are all critical to the regulation of gene transcription. HDAC-2 function is impaired by oxidative stress in a PI3Kδ dependant manner which may be involved in the chronic glucocorticoid insensitive inflammation in the lungs of COPD patients. However, the impact of cigarette smoke exposure on the expression of mSin3a and Mi2α/β and their role in glucocorticoid responsiveness is unknown.</p> <p>Methods</p> <p>Wild type, PI3Kγ knock-out (PI3Kγ^-/-) and PI3K kinase dead knock-in (PI3Kδ^D910/A910) transgenic mice were exposed to cigarette smoke for 3 days and the expression levels of the co-repressor complex components HDAC-2, mSin3a, Mi-2α and Mi-2β and HDAC-2 activity in the lungs were assessed.</p> <p>Results</p> <p>Cigarette smoke exposure impaired glucocorticoid function and reduced HDAC-2 activity which was protected in the PI3Kδ^D910/A910mice. Both mSin3a and Mi-2α protein expression was reduced in smoke-exposed mice. Budesonide alone protected mSin3a protein expression with no additional effect seen with abrogation of PI3Kγ/δ activity, however Mi-2α, but not Mi-2β, expression was protected in both PI3Kδ^D910/A910and PI3Kγ^-/-budesonide-treated smoke-exposed mice. The restoration of glucocorticoid function coincided with the protection of both HDAC activity and mSin3a and Mi-2α protein expression.</p> <p>Conclusions</p> <p>Cigarette smoke exposure induced glucocorticoid insensitivity and alters co-repressor activity and expression which is prevented by blockade of PI3K signaling with glucocorticoid treatment. Inhibition of PI3Kδ signalling in combination with glucocorticoid treatment may therefore provide a therapeutic strategy for restoring oxidant-induced glucocortiocid unresponsiveness.</p

Critical Currents, Pinning Forces and Irreversibility Fields in (YxTml-x)Ba2Cu3O7 Single Crystals with Columnar Defects in Fields up to 50 T

We have studied the influence of columnar defects, created by heavy-ion (Kr) irradiation with doses up to 6 10^11 Kr-ions/cm2, on the superconducting critical parameters of single crystalline (YxTm1-x)Ba2Cu3O7. Magnetisation measurements in pulsed fields up to 50 T in the temperature range 4.2 - 90 K revealed that: (i) in fields up to T the critical current Jc(H,T) is considerably enhanced and (ii) down to temperatures T ~ 40 K the irreversibility field Hirr(T) is strongly increased. The field range and magnitude of the Jc(H,T) and Hirr(T) enhancement increase with increasing irradiation dose. To interpret these observations, an effective matching field was defined. Moreover, introducing columnar defects also changes the pinning force fp qualitatively. Due to stronger pinning of flux lines by the amorphous defects, the superconducting critical parameters largely exceed those associated with the defect structures in the unirradiated as-grown material: Jc,irrad(77 K, 5 T) ^3 10* Jc,ref(77 K, 5 T).Comment: 11 pages, all PDF, contribution to Physica