5,630 research outputs found

    Non-Abelian Magnetized Blackholes and Unstable Attractors

    Get PDF
    Fluctuations of non-Abelian gauge fields in a background magnetic flux contain tachyonic modes and hence the background is unstable. We extend these results to the cases where the background flux is coupled to Einstein gravity and show that the corresponding spherically symmetric geometries, which in the absence of a cosmological constant are of the form of Reissner-Nordstrom blackholes or the AdS_2xS^2, are also unstable. We discuss the relevance of these instabilities to several places in string theory including various string compactifications and the attractor mechanism. Our results for the latter imply that the attractor mechanism shown to work for the extremal Abelian charged blackholes, cannot be applied in a straightforward way to the extremal non-Abelian colored blackholes.Comment: 23 pages, 3 .eps figures; v2: Stability of minimal charge blackhole emphasized, Refs adde

    How Schools Affect Student Well-Being: A Cross-Cultural Approach in 35 OECD Countries

    Get PDF
    A common approach for measuring the effectiveness of an education system or a school is the estimation of the impact that school interventions have on students’ academic performance. However, the latest trends aim to extend the focus beyond students’ acquisition of knowledge and skills, and to consider aspects such as well-being in the academic context. For this reason, the 2015 edition of the international assessment system Programme for International Student Assessment (PISA) incorporated a new tool aimed at evaluating the socio-emotional variables related to the well-being of students. It is based on a definition focused on the five dimensions proposed in the PISA theoretical framework: cognitive, psychological, social, physical, and material. The main purpose of this study is to identify the well-being components that significantly affect student academic performance and to estimate the magnitude of school effects on the wellbeing of students in OECD countries, the school effect being understood as the ability of schools to increase subjective student well-being. To achieve this goal, we analyzed the responses of 248,620 students from 35 OECD countries to PISA 2015 questionnaires. Specifically, we considered non-cognitive variables in the questionnaires and student performance in science. The results indicated that the cognitive well-being dimension, composed of enjoyment of science, self-efficacy, and instrumental motivation, as well as test anxiety all had a consistent relationship with student performance across countries. In addition, the school effect, estimated through a two-level hierarchical linear model, in terms of student well-being was systematically low. While the school effect accounted for approximately 25% of the variance in the results for the cognitive dimension, only 5–9% of variance in well-being indicators was attributable to it. This suggests that the influence of school on student welfare is weak, and the effect is similar across countries. The present study contributes to the general discussion currently underway about the definition of well-being and the connection between well-being and achievement. The results highlighted two complementary concerns: there is a clear need to promote socioemotional education in schools, and it is important to develop a rigorous framework for well-being assessment. The implications of the results and proposals for future studies are discussed.Spain Ministry of Science, Innovation and Universities PSI2017-85724-P2E Estudios, Evaluaciones e Investigacion, S.

    Development and Validation of a Modified Multiple Errands Test for Adults with Intellectual Disabilities

    Get PDF
    Background: The aims of the current study were to adapt a version of the MET for people with intellectual disabilities (IDs) and assess its ecological and construct validity. Material and Methods: Using a correlational design, 40 participants with IDs were invited to complete a battery of neuropsychological assessments and the modified Multiple Errands Test for Intellectual Disabilities (mMET-IDs). Results: The ability to successfully complete tasks on the mMET-IDs correlated significantly with measures of the Supervisory Attentional System, namely, the Tower of London Test and the Six Parts Test. However, performance on the mMET-IDs and the Six Parts Test could be accounted for by Verbal IQ and receptive vocabulary. The mMET-IDs failed to correlate with the DEX-IR. Conclusions: The mMET-IDs can be successfully used to assess some aspects of the Supervisory Attentional System in people with IDs. Further development is needed, however, to improve the ecological validity of the mMET-IDs

    HPV transcript expression affects cervical cancer response to chemoradiation

    Get PDF
    Persistent HPV infection is causative for the majority of cervical cancer cases; however, current guidelines do not require HPV testing for newly diagnosed cervical cancer. Using an institutional cohort of 88 patients with cervical cancer treated uniformly with standard-of-care chemoradiation treatment (CRT) with prospectively collected clinical outcome data, we observed that patients with cervical tumors containing HPV genotypes other than HPV 16 have worse survival outcomes after CRT compared with patients with HPV 16+ tumors, consistent with previously published studies. Using RNA sequencing analysis, we quantified viral transcription efficiency and found higher levels of E6 and the alternative transcript E6*I in cervical tumors with HPV genotypes other than HPV 16. These findings were validated using whole transcriptome data from The Cancer Genome Atlas (n = 304). For the first time to our knowledge, transcript expression level of HPV E6*I was identified as a predictive biomarker of CRT outcome in our complete institutional data set (n = 88) and within the HPV 16+ subset (n = 36). In vitro characterization of HPV E6*I and E6 overexpression revealed that both induce CRT resistance through distinct mechanisms dependent upon p53-p21. Our findings suggest that high expression of E6*I and E6 may represent novel biomarkers of CRT efficacy, and these patients may benefit from alternative treatment strategies

    Assessing the Effectiveness of House-to-House Visits on Routine Oral Polio Immunization Completion and Tracking of Defaulters

    Get PDF
    Strengthening routine immunization is one of the four prongs of the Global Polio Eradication Initiative. Using data collected through 30-cluster sample household surveys of caretakers of children aged 12-23 months, this paper assessed the effectiveness of house-to-house visits on routine oral polio immunization completion, using simple frequency tables, bivariate and multivariate logistic regression analyses. Logistic regression results demonstrated that children in households where the caregivers reported receiving a household visit by health workers were more likely to be fully immunized for polio through routine immunization than other children, although results were significant only after correcting for confounders. In Ethiopia and India, children of caregivers who remembered a house-to-house visit were significantly and positively associated with routine polio vaccination completion (OR=2.2 and OR=2.2 respectively). In Angola, the association was positive, though not significant (OR=1.3). The evidence suggests that targeting high-risk areas for house-to-house visits played a role in increasing routine polio vaccination
    corecore