Mathematics, computers in mathematics, and gender: public perceptions in context

In Australia, national tests of mathematics achievement continue showing small but consistent gender differences in favor of boys. Societal views and pressures are among the factors invoked to explain such subtle but persistent differences. In this paper we focus directly on the beliefs of the general public about students’ learning of mathematics and the role played by computers, and then we compare the findings with data previously gathered from students. Although many considered it inappropriate to differentiate between boys and girls, gender based stereotyping was still evident

Infrared analysis of propagators and vertices of Yang--Mills theory in Landau and Coulomb gauge

The infrared behaviour of gluon and ghost propagators, ghost-gluon vertex and three-gluon vertex is investigated for both the covariant Landau and the non-covariant Coulomb gauge. Assuming infrared ghost dominance, we find a unique infrared exponent in the d=4 Landau gauge, while in the d=3+1 Coulomb gauge we find two different infrared exponents. We also show that a finite dressing of the ghost-gluon vertex has no influence on the infrared exponents. Finally, we determine the infrared behaviour of the three-gluon vertex analytically and calculate it numerically at the symmetric point in the Coulomb gauge.Comment: 25 pages, 6 figures, accepted by Phys. Rev. D, references added, typos correcte

Facing the Sublime: Physiological Correlates of the Relationship Between Fear and the Sublime

The sublime is an enduring concept in Western aesthetic discourse and is often portrayed such as in Edmund Burke’s A Philosophical Enquiry into the Origin of Our Ideas of the Sublime and Beautiful of 1759 as a delightful horror, a kind of enjoyment based on negative emotions. In the current article, the relationship between sublimity and fear was explored using behavioral and physiological measures. In 2 studies (total N ≈ 120), photographs of nature were selected (Study 1: 192 photographs and Study 2: 72 photographs), rated on sublimity, beauty, fear, happiness, and arousal, before being assessed against facial muscle movement (fEMG) and skin conductance (SCR). In line with philosophical theories, ratings of sublimity showed positive associations with subjective fear ratings in both studies. Looking at fEMG data (Study 2), sublimity was in fact associated with a decrease of corrugator supercilli (frowning) reactions, indicating reduced emotional negativity. Furthermore, sublimity did not change activation levels of the zygomaticus major (smiling/positive emotional valence), nor did it influence movements of the medial frontalis (inner brow raise/fear). Increased ratings of fear increased corrugator supercilii and medial frontalis activations, and decreased zygomaticus major activation, replicating past findings. SCR activation was not predicted by any variable. The discrepancy between behavioral and physiological results likely results from a combination of false appraisal and distancing mechanisms, and thus encourages the reconsideration of generalizations made over the sublime in its relation to fear

Linear and nonlinear optical characteristics of the Falicov-Kimball model

We calculate the linear and nonlinear optical properties of the Falicov-Kimball model for a mixed-valent system within the self-consistent mean-field approximation. Second-harmonic generation can only occur if the mixed-valent state has a built-in coherence between the itinerant d-electrons and the localized f-holes. By contrast, second-harmonic generation cannot occur for solutions of the model with f-site occupation as a good quantum number. As an experimental test of coherence in mixed-valent compounds we propose a measurement of the dynamic second-order susceptibility.Comment: 4 pages, 2 PostScript figures, to appear in Physical Review Letter

Functional approaches to infrared Yang-Mills theory in the Coulomb gauge

We present the current status of ongoing efforts to use functional methods, Dyson-Schwinger equations and functional renormalization group equations, for the description of the infrared regime of nonabelian (pure) gauge theories in the Coulomb gauge. In particular, we present a new determination of the color-Coulomb potential with the help of the functional renormalization group that results in an almost linearly rising potential between static color charges at large spatial distances.Comment: 11 pages, 3 figures. Slightly improved version of J. Phys.: Conf. Ser. 287 (2011) 01202

Measuring telomere length and telomere dynamics in evolutionary biology and ecology

Telomeres play a fundamental role in the protection of chromosomal DNA and in the regulation of cellular senescence. Recent work in human epidemiology and evolutionary ecology suggests adult telomere length (TL) may reflect past physiological stress and predict subsequent morbidity and mortality, independent of chronological age. Several different methods have been developed to measure TL, each offering its own technical challenges. The aim of this review is to provide an overview of the advantages and drawbacks of each method for researchers, with a particular focus on issues that are likely to face ecologists and evolutionary biologists collecting samples in the field or in organisms that may never have been studied in this context before. We discuss the key issues to consider and wherever possible try to provide current consensus view regarding best practice with regard to sample collection and storage, DNA extraction and storage, and the five main methods currently available to measure TL. Decisions regarding which tissues to sample, how to store them, how to extract DNA, and which TL measurement method to use cannot be prescribed, and are dependent on the biological question addressed and the constraints imposed by the study system. What is essential for future studies of telomere dynamics in evolution and ecology is that researchers publish full details of their methods and the quality control thresholds they employ