Beam-induced backgrounds measured in the ATLAS detector during local gas injection into the LHC beam vacuum

Inelastic beam-gas collisions at the Large Hadron Collider (LHC), within a few hundred metres of the ATLAS experiment, are known to give the dominant contribution to beam backgrounds. These are monitored by ATLAS with a dedicated Beam Conditions Monitor (BCM) and with the rate of fake jets in the calorimeters. These two methods are complementary since the BCM probes backgrounds just around the beam pipe while fake jets are observed at radii of up to several metres. In order to quantify the correlation between the residual gas density in the LHC beam vacuum and the experimental backgrounds recorded by ATLAS, several dedicated tests were performed during LHC Run 2. Local pressure bumps, with a gas density several orders of magnitude higher than during normal operation, were introduced at different locations. The changes of beam-related backgrounds, seen in ATLAS, are correlated with the local pressure variation. In addition the rates of beam-gas events are estimated from the pressure measurements and pressure bump profiles obtained from calculations. Using these rates, the efficiency of the ATLAS beam background monitors to detect beam-gas events is derived as a function of distance from the interaction point. These efficiencies and characteristic distributions of fake jets from the beam backgrounds are found to be in good agreement with results of beam-gas simulations performed with theFluka Monte Carlo programme

Search for heavy Majorana neutrinos in e±e± and e±μ± final states via WW scattering in pp collisions at √s = 13 TeV with the ATLAS detector

A search for heavy Majorana neutrinos in scattering of same-sign W boson pairs in proton–proton collisions at √s = 13 TeV at the LHC is reported. The dataset used corresponds to an integrated luminosity of 140 fb−1, collected with the ATLAS detector during 2015–2018. The search is performed in final states including a same-sign ee or eμ pair and at least two jets with large invariant mass and a large rapidity difference. No significant excess of events with respect to the Standard Model background predictions is observed. The results are interpreted in a benchmark scenario of the Phenomenological Type-I Seesaw model. New constraints are set on the values of the |VeN|2 and |VeN V*μN| parameters for heavy Majorana neutrino masses between 50 GeV and 20 TeV, where VℓN is the matrix element describing the mixing of the heavy Majorana neutrino mass eigenstate with the Standard Model neutrino of flavour ℓ = e, μ. The sensitivity to the Weinberg operator is investigated and constraints on the effective ee and eμ Majorana neutrino masses are reported. The statistical combination of the ee and eμ channels with the previously published μμ channel is performed

Search for heavy, long-lived, charged particles with large ionisation energy loss in pp collisions at √s = 13 TeV using the ATLAS experiment and the full Run 2 dataset

This paper presents a search for hypothetical massive, charged, long-lived particles with the ATLAS detector at the LHC using an integrated luminosity of 139 fb−1 of proton–proton collisions at √s = 13 TeV. These particles are expected to move significantly slower than the speed of light and should be identifiable by their high transverse momenta and anomalously large specific ionisation losses, dE/dx. Trajectories reconstructed solely by the inner tracking system and a dE/dx measurement in the pixel detector layers provide sensitivity to particles with lifetimes down to O (1) ns with a mass, measured using the Bethe–Bloch relation, ranging from 100 GeV to 3 TeV. Interpretations for pair-production of R-hadrons, charginos and staus in scenarios of supersymmetry compatible with these particles being long-lived are presented, with mass limits extending considerably beyond those from previous searches in broad ranges of lifetime

Successes and failures of the gifted education programme in Singapore.

This report discussed the successes & failures of the gifted education programme in Singapore.Bachelor of Communication Studie

Teacher bullying: the case of Singapore

In 1993, the first few cases of teacher bullying, when teachers used their power to punish, manipulate or disparage a student beyond what would be a reasonable disciplinary procedure, began to catch the mainstream media’s attention. Since then, few studies have focused on teacher bullying globally and even lesser in Asia, where such a phenomenon carries a stigma attached to it. Considering the stark differences between Western and Asian cultures, especially in terms of the power distances between students and teachers, there emerges a need to address this gap in the teacher bullying literature. The study aims to investigate how teacher bullying occurs in an Asian context, with Singapore as the chosen sample of interest. Using semi -structured interviews, the experiences of the non-probability sample of affected students (four men, one woman), were examined through an Interpretative Phenomenological perspective. Findings indicated that teacher bullying existed, involving public humiliation of students, such as shaming, as well as other forms of abusive power towards students. Key findings included a two-stage process of teacher bullying in the form of disparagement amongst other significant findings. It is recommended that policies address acceptable and appropriate behaviour within the teaching context

The manipulation of synchronous internet-based online social support in a laboratory setting

The present study aimed to manipulate Internet-based online social support (OS) in a laboratory setting and compare its effect with face-to-face social support (FS). Participants (N = 161) were randomly assigned to either alone, FS, or OS condition. Consistent with the hypotheses, alone participants perceived less social support than supported participants and experienced less positive emotions than those who received OS. For all the DVs, FS and OS did not differ from each other. The results ascertained the equivalent benefit of OS to FS. Most importantly, these findings highlighted successful manipulation of synchronous OS in a laboratory setting

Gender as moderator of the effects of online social support from friends and strangers: a study of Singaporean college students

Gender differences in Internet use may affect how women and men respond to online support (OS) provided by friends and strangers. The present study compared the psychological effects of brief OS provided by a same-gender, same-ethnicity friend or stranger in young Singaporean women (n = 73) and men (n = 60). After random assignment to 1 of 3 groups (supportive friend, supportive stranger, nothing), Singaporean university students completed stressor tasks before and after instant messaging with a friend or stranger, or doing nothing. The findings showed that OS from a friend attenuated women’s negative emotional responses to stress, whereas OS from a stranger was ineffective in regulating women’s negative affect. In contrast, men did not show significant changes in negative affect in association with OS provided by a friend or a stranger. The findings were consistent with gender differences in Internet use, where women use the Internet to seek social support and men to gather information

Sleep and dietary patterns in pregnancy: Findings from the gusto cohort

Evidence on the association between sleep, diet, and eating behaviors in pregnant women is lacking. We examine this in a cohort of apparently healthy pregnant women. At 26–28 weeks gestation, 497 participants completed the Pittsburgh Sleep Quality Index to assess sleep and a 24-h recall to assess dietary intake. Diet quality was assessed by the Healthy Eating Index for pregnant women in Singapore (HEI-SGP) score and previously derived dietary patterns (vegetables-fruit-rice, seafood-noodles, and pasta-cheese-meat pattern). Eating behaviors studied included the longest night-time fasting interval, frequency of consumption occasions, energy from discretionary foods, and night-time eating. Adjusted means were estimated between poor/good quality and short/normal sleepers using linear regressions, including covariates. Good sleep quality versus poor sleep quality, was associated with better diet quality (mean HEI‐SGP 54.6 vs. 52.0; p = 0.032), greater adherence to the vegetables-fruit-rice pattern (mean 0.03 vs. −0.15; p = 0.039), lesser adherence to the seafood-noodle pattern (mean −0.14 vs. 0.03; p = 0.024), and a trending lower calories from discretionary foods (mean 330.5 vs. 382.6 kcal; p = 0.073), after adjusting for covariates. After additional adjustment for anxiety, only sleep quality and the seafood‐noodle pattern remained significantly associated (p = 0.018). Short sleep was not associated with any diet or eating behavior. In conclusion, good sleep quality is associated with a better diet quality and a greater adherence to the vegetable-fruit-rice pattern, but with lesser adherence to the seafood-noodle diets in pregnant women