192 research outputs found

    Connectedness and chainability in metric spaces

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    University students’ classroom emotional climate and attitudes during and after COVID-19 lockdown

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    With the advent of COVID-19, universities around the world have been forced to move to a fully online mode of delivery because of lockdown policies. This led to a flurry of studies into issues such as internet access, student attitudes to online learning and mental health during lockdown. However, researchers need a validated survey for assessing the classroom emotional climate and student attitudes towards learning in universities that can be used for online, face-to-face or blended delivery. Such a survey could be used to illuminate students’ perceptions of the experiences that make up learning at university level, in terms of such factors as care from teachers, collaboration and motivation. In this article, we report the validation of a University Classroom Emotional Climate (UCEC) questionnaire and an Attitudes to Learning scale, as well as their use in comparing the classroom emotional climate and attitudes during COVID-19 lockdown (fully online delivery) with post-lockdown (mixed-mode delivery). Female students experienced the post-lockdown condition significantly more positively than during lockdown for all scales except Care, while the only significant difference for males between the during and post-lockdown was their choice to engage with learning (Control) and the degree of Challenge that they found with the learning materials

    Self-Averaging, Distribution of Pseudo-Critical Temperatures and Finite Size Scaling in Critical Disordered Systems

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    The distributions P(X)P(X) of singular thermodynamic quantities in an ensemble of quenched random samples of linear size ll at the critical point TcT_c are studied by Monte Carlo in two models. Our results confirm predictions of Aharony and Harris based on Renormalization group considerations. For an Ashkin-Teller model with strong but irrelevant bond randomness we find that the relative squared width, RXR_X, of P(X)P(X) is weakly self averaging. RXlα/νR_X\sim l^{\alpha/\nu}, where α\alpha is the specific heat exponent and ν\nu is the correlation length exponent of the pure model fixed point governing the transition. For the site dilute Ising model on a cubic lattice, known to be governed by a random fixed point, we find that RXR_X tends to a universal constant independent of the amount of dilution (no self averaging). However this constant is different for canonical and grand canonical disorder. We study the distribution of the pseudo-critical temperatures Tc(i,l)T_c(i,l) of the ensemble defined as the temperatures of the maximum susceptibility of each sample. We find that its variance scales as (δTc(l))2l2/ν(\delta T_c(l))^2 \sim l^{-2/\nu} and NOT as ld.Wefindthat\sim l^{-d}. We find that R_\chiisreducedbyafactorof is reduced by a factor of \sim 70withrespectto with respect to R_\chi (T_c)bymeasuring by measuring \chiofeachsampleat of each sample at T_c(i,l).Weanalyzecorrelationsbetweenthemagnetizationatcriticality. We analyze correlations between the magnetization at criticality m_i(T_c,l)andthepseudocriticaltemperature and the pseudo-critical temperature T_c(i,l)intermsofasampleindependentfinitesizescalingfunctionofasampledependentreducedtemperature in terms of a sample independent finite size scaling function of a sample dependent reduced temperature (T-T_c(i,l))/T_c$. This function is found to be universal and to behave similarly to pure systems.Comment: 31 pages, 17 figures, submitted to Phys. Rev.

    Identifying potential causal effects of age at menarche: A Mendelian randomization phenome-wide association study

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    Background: Age at menarche has been associated with various health outcomes. We aimed to identify potential causal effects of age at menarche on health-related traits in a hypothesis-free manner. Methods: We conducted a Mendelian randomization phenome-wide association study (MR-pheWAS) of age at menarche with 17,893 health-related traits in UK Biobank (n = 181,318) using PHESANT. The exposure of interest was the genetic risk score for age at menarche. We conducted a second MR-pheWAS after excluding SNPs associated with BMI from the genetic risk score, to examine whether results might be due to the genetic overlap between age at menarche and BMI. We followed up a subset of health-related traits to investigate MR assumptions and seek replication in independent study populations. Results: Of the 17,893 tests performed in our MR-pheWAS, we identified 619 associations with the genetic risk score for age at menarche at a 5% false discovery rate threshold, of which 295 were below a Bonferroni-corrected P value threshold. These included potential effects of younger age at menarche on lower lung function, higher heel bone-mineral density, greater burden of psychosocial/mental health problems, younger age at first birth, higher risk of childhood sexual abuse, poorer cardiometabolic health, and lower physical activity. After exclusion of variants associated with BMI, the genetic risk score for age at menarche was related to 37 traits at a 5% false discovery rate, of which 29 were below a Bonferroni-corrected P value threshold. We attempted to replicate findings for bone-mineral density, lung function, neuroticism, and childhood sexual abuse using 5 independent cohorts/consortia. While estimates for lung function, higher bone-mineral density, neuroticism, and childhood sexual abuse in replication cohorts were consistent with UK Biobank estimates, confidence intervals were wide and often included the null. Conclusions: The genetic risk score for age at menarche was related to a broad range of health-related traits. Follow-up analyses indicated imprecise evidence of an effect of younger age at menarche on greater bone-mineral density, lower lung function, higher neuroticism score, and greater risk of childhood sexual abuse in the smaller replication samples available; hence, these findings need further exploration when larger independent samples become available

    Symmetry-breaking Effects for Polariton Condensates in Double-Well Potentials

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    We study the existence, stability, and dynamics of symmetric and anti-symmetric states of quasi-one-dimensional polariton condensates in double-well potentials, in the presence of nonresonant pumping and nonlinear damping. Some prototypical features of the system, such as the bifurcation of asymmetric solutions, are similar to the Hamiltonian analog of the double-well system considered in the realm of atomic condensates. Nevertheless, there are also some nontrivial differences including, e.g., the unstable nature of both the parent and the daughter branch emerging in the relevant pitchfork bifurcation for slightly larger values of atom numbers. Another interesting feature that does not appear in the atomic condensate case is that the bifurcation for attractive interactions is slightly sub-critical instead of supercritical. These conclusions of the bifurcation analysis are corroborated by direct numerical simulations examining the dynamics of the system in the unstable regime.MICINN (Spain) project FIS2008- 0484

    Anthropogenic Space Weather

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    Anthropogenic effects on the space environment started in the late 19th century and reached their peak in the 1960s when high-altitude nuclear explosions were carried out by the USA and the Soviet Union. These explosions created artificial radiation belts near Earth that resulted in major damages to several satellites. Another, unexpected impact of the high-altitude nuclear tests was the electromagnetic pulse (EMP) that can have devastating effects over a large geographic area (as large as the continental United States). Other anthropogenic impacts on the space environment include chemical release ex- periments, high-frequency wave heating of the ionosphere and the interaction of VLF waves with the radiation belts. This paper reviews the fundamental physical process behind these phenomena and discusses the observations of their impacts.Comment: 71 pages, 35 figure

    DNA mismatch repair gene MSH6 implicated in determining age at natural menopause

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    The length of female reproductive lifespan is associated with multiple adverse outcomes, including breast cancer, cardiovascular disease and infertility. The biological processes that govern the timing of the beginning and end of reproductive life are not well understood. Genetic variants are known to contribute to ∼50% of the variation in both age at menarche and menopause, but to date the known genes explain <15% of the genetic component. We have used genome-wide association in a bivariate meta-analysis of both traits to identify genes involved in determining reproductive lifespan. We observed significant genetic correlation between the two traits using genome-wide complex trait analysis. However, we found no robust statistical evidence for individual variants with an effect on both traits. A novel association with age at menopause was detected for a variant rs1800932 in the mismatch repair gene MSH6 (P = 1.9 × 10−9), which was also associated with altered expression levels of MSH6 mRNA in multiple tissues. This study contributes to the growing evidence that DNA repair processes play a key role in ovarian ageing and could be an important therapeutic target for infertilit

    A Historiometric Examination of Machiavellianism and a New Taxonomy of Leadership

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    Although researchers have extensively examined the relationship between charismatic leadership and Machiavellianism (Deluga, 2001; Gardner & Avolio, 1995; House & Howell, 1992), there has been a lack of investigation of Machiavellianism in relation to alternative forms of outstanding leadership. Thus, the purpose of this investigation was to examine the relationship between Machiavellianism and a new taxonomy of outstanding leadership comprised of charismatic, ideological, and pragmatic leaders. Using an historiometric approach, raters assessed Machiavellianism via the communications of 120 outstanding leaders in organizations across the domains of business, political, military, and religious institutions. Academic biographies were used to assess twelve general performance measures as well as twelve general controls and five communication specific controls. The results indicated that differing levels of Machiavellianism is evidenced across the differing leader types as well as differing leader orientation. Additionally, Machiavellianism appears negatively related to performance, though less so when type and orientation are taken into account.Yeshttps://us.sagepub.com/en-us/nam/manuscript-submission-guideline
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