1,713 research outputs found
On the Fixed-Point Structure of Scalar Fields
In a recent Letter (K.Halpern and K.Huang, Phys. Rev. Lett. 74 (1995) 3526),
certain properties of the Local Potential Approximation (LPA) to the Wilson
renormalization group were uncovered, which led the authors to conclude that
dimensional scalar field theories endowed with {\sl non-polynomial}
interactions allow for a continuum of renormalization group fixed points, and
that around the Gaussian fixed point, asymptotically free interactions exist.
If true, this could herald very important new physics, particularly for the
Higgs sector of the Standard Model. Continuing work in support of these ideas,
has motivated us to point out that we previously studied the same properties
and showed that they lead to very different conclusions. Indeed, in as much as
the statements in hep-th/9406199 are correct, they point to some deep and
beautiful facts about the LPA and its generalisations, but however no new
physics.Comment: Typos corrected. A Comment - to be published in Phys. Rev. Lett. 1
page, 1 eps figure, uses LaTeX, RevTex and eps
Investigating how the accuracy of teacher expectations of pupil performance relate to socioeconomic and genetic factors
Teacher expectations of pupil ability can influence educational progression, impacting subsequent streaming and exam level. Systematic discrepancies between teacher expectations of pupil achievement may therefore have a detrimental effect on children’s education. Associations between socioeconomic and demographic factors with teacher expectation accuracy have been demonstrated, but it is not known how teacher expectations of achievement may relate to genetic factors. We investigated these relationships using nationally standardized exam results at ages 11 and 14 from a UK longitudinal cohort study. We found that teacher expectation of achievement was strongly correlated with educational test scores. Furthermore, the accuracy of teacher expectation was patterned by pupil socioeconomic background but not teacher characteristics. The accuracy of teacher expectation related to pupil’s genetic liability to education as captured by a polygenic score for educational attainment. Despite correlation with the polygenic score, we found no strong evidence for genomewide SNP heritability in teacher reporting accuracy
Conformal anomaly from gauge fields without gauge fixing
We show how the Weyl anomaly generated by gauge fields, can be computed from
manifestly gauge invariant and diffeomorphism invariant exact renormalization
group equations, without having to fix the gauge at any stage. Regularisation
is provided by covariant higher derivatives and by embedding the Maxwell field
into a spontaneously broken supergauge theory. We first provide a
realisation that leaves behind two versions of the original gauge field,
and then construct a manifestly supergauge invariant flow equation
which leaves behind only the original Maxwell field in the spontaneously broken
regime.Comment: 24 page
Population phenomena inflate genetic associations of complex social traits
Heritability, genetic correlation, and genetic associations estimated from samples of unrelated individuals are often perceived as confirmation that genotype causes the phenotype(s). However, these estimates can arise from indirect mechanisms due to population phenomena including population stratification, dynastic effects, and assortative mating. We introduce these, describe how they can bias or inflate genotype-phenotype associations, and demonstrate methods that can be used to assess their presence. Using data on educational achievement and parental socioeconomic position as an exemplar, we demonstrate that both heritability and genetic correlation may be biased estimates of the causal contribution of genotype. These results highlight the limitations of genotype-phenotype estimates obtained from samples of unrelated individuals. Use of these methods in combination with family-based designs may offer researchers greater opportunities to explore the mechanisms driving genotype-phenotype associations and identify factors underlying bias in estimates
Height, social position and coronary heart disease incidence: the contribution of genetic and environmental factors
Background: The associations between height, socioeconomic position (SEP) and coronary heart disease (CHD) incidence are well established, but the contribution of genetic factors to these associations is still poorly understood. We used a polygenic score (PGS) for height to shed light on these associations. Methods: Finnish population-based health surveys in 1992-2011 (response rates 65-93%) were linked to population registers providing information on SEP and CHD incidence up to 2019. The participants (N=29 996; 54% women) were aged 25-75 at baseline, and there were 1767 CHD incident cases (32% in women) during 472 973 person years of follow-up. PGS-height was calculated based on 33 938 single-nucleotide polymorphisms, and residual height was defined as the residual of height after adjusting for PGS-height in a linear regression model. HRs of CHD incidence were calculated using Cox regression. Results: PGS-height and residual height showed clear gradients for education, social class and income, with a larger association for residual height. Residual height also showed larger associations with CHD incidence (HRs per 1 SD 0.94 in men and 0.87 in women) than PGS-height (HRs per 1 SD 0.99 and 0.97, respectively). Only a small proportion of the associations between SEP and CHD incidence was statistically explained by the height indicators (6% or less). Conclusions: Residual height associations with SEP and CHD incidence were larger than for PGS-height. This supports the role of material and social living conditions in childhood as contributing factors to the association of height with both SEP and CHD risk
Two Phases for Compact U(1) Pure Gauge Theory in Three Dimensions
We show that if actions more general than the usual simple plaquette action
() are considered, then compact {\sl pure} gauge
theory in three Euclidean dimensions can have two phases. Both phases are
confining phases, however in one phase the monopole condensate spontaneously
`magnetizes'. For a certain range of parameters the phase transition is
continuous, allowing the definition of a strong coupling continuum limit. We
note that these observations have relevance to the `fictitious' gauge field
theories of strongly correlated electron systems, such as those describing
high- superconductors.Comment: 10 pages, Plain TeX, uses harvma
Maternal depressive symptoms and young people's higher education participation and choice of university: Evidence from a longitudinal cohort study
Background:
Participation in higher education has significant and long-lasting consequences for people's socioeconomic trajectories. Maternal depression is linked to poorer educational achievement for children in school, but its impact on university attendance is unclear.
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Methods:
In an English longitudinal cohort study (N = 8952), we explore whether young people whose mothers experienced elevated depressive symptoms are less likely to attend university, and the role of potential mediators in the young person: educational achievement in school, depressive symptoms, and locus of control. We also examine whether maternal depressive symptoms influence young people's choice of university, and non-attendees' reasons for not participating in higher education.
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Results:
Young people whose mothers experienced more recurrent depressive symptoms were less likely to attend university (OR = 0.88, CI = 0.82,0.94, p < 0.001) per occasion of elevated maternal depressive symptoms) after adjusting for confounders. Mediation analysis indicated this was largely explained by educational achievement in school (e.g., 82.7 % mediated by age 16 achievement) and locus of control at 16. There was mixed evidence for an impact on choice of university. For participants who did not study at university, maternal depressive symptoms were linked to stating as a reason having had other priorities to do with family or children (OR: 1.17, CI = 1.02,1.35).
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Limitations:
Lack of data on the other parent's depression, loss to follow-up, possibly selective non-response.
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Conclusions:
Young people whose mothers experience elevated depressive symptoms on multiple occasions are less likely to participate in higher education; educational achievement in secondary school, but not the young people's own depressive symptoms, substantially mediated the effect
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