Chemical Timescales in the Atmospheres of Highly Eccentric Exoplanets

Close-in exoplanets with highly eccentric orbits are subject to large variations in incoming stellar flux between periapse and apoapse. These variations may lead to large swings in atmospheric temperature, which in turn may cause changes in the chemistry of the atmosphere from higher CO abundances at periapse to higher CH4 abundances at apoapse. Here we examine chemical timescales for COCH4 interconversion compared to orbital timescales and vertical mixing timescales for the highly eccentric exoplanets HAT-P-2b and CoRoT-10b. As exoplanet atmospheres cool, the chemical timescales for COCH4 tend to exceed orbital and/or vertical mixing timescales, leading to quenching. The relative roles of orbit-induced thermal quenching and vertical quenching depend upon mixing timescales relative to orbital timescales. For both HAT-P-2b and CoRoT-10b, vertical quenching will determine disequilibrium COCH4 chemistry at faster vertical mixing rates (Kzz > 10^7 cm^2 s^-1), whereas orbit-induced thermal quenching may play a significant role at slower mixing rates (Kzz < 10^7 cm^2 s^-1). The general abundance and chemical timescale results - calculated as a function of pressure, temperature, and metallicity - can be applied for different atmospheric profiles in order to estimate the quench level and disequilibrium abundances of CO and CH4 on hydrogen-dominated exoplanets. Observations of CO and CH4 on highly eccentric exoplanets may yield important clues to the chemical and dynamical properties of their atmospheres.Comment: 9 pages, 4 figures, accepted for publication in the Astrophysical Journal; v2 corrects typos and figure resolution issue

Can mothers judge the size of their newborn? Assessing the determinants of a mother's perception of a baby's size at birth

Birth weight is known to be closely related to child health, although as many infants in developing countries are not weighed at birth and thus will not have a recorded birth weight it is difficult to use birth weight when analysing child illness. It is common to use a proxy for birth weight instead, namely the mother’s perception of the baby’s size at birth. Using DHS surveys in Cambodia, Kazakhstan and Malawi the responses to this question were assessed to indicate the relationship between birth weight and mother’s perception. The determinants of perception were investigated using multilevel ordinal regression to gauge if they are different for infants with and without a recorded birth weight, and to consider if there are societal or community influences on perception of size. The results indicate that mother’s perception is closely linked to birth weight, although there are other influences on the classification of infants into size groups. On average, a girl of the same birth weight as a boy will be classified into a smaller size category. Likewise, infants who died by the time of the survey will be classified as smaller than similarly heavy infants who are still alive. There are significant variations in size perception between sampling districts and clusters, indicating that mothers mainly judge their child for size against a national norm. However, there is also evidence that the size of infants in the community around the newborn also has an effect on the final size perception classification. Overall the results indicate that mother’s perception of size is a good proxy for birth weight in large nationally representative surveys, although care should be taken to control for societal influences on perception

Inverted Sugar: Generalized Ray Tracing Algorithm

Though particular algorithms utilizing Snell’s Law effectively describe most ray tracing, issues arise with infrasound applications, particularly in understanding waveguides. A more generalized differential equation derived from Fermat’s principle of least time and general functions may provide a computational solution to coupling ray tracing with wavelength related issues. However, due to its complexity, this differential equation deserves its own experimentation to confirm or deny its effectiveness. In this experiment, a gradient of index of refraction established by the diffusion of sugar emulated an atmospheric temperature inversion (hence “Inverted Sugar”) and comparison of actual rays to computer generated rays in the same gradient confirmed the accuracy of this algorithm

Critical mutation rate has an exponential dependence on population size in haploid and diploid populations

Understanding the effect of population size on the key parameters of evolution is particularly important for populations nearing extinction. There are evolutionary pressures to evolve sequences that are both fit and robust. At high mutation rates, individuals with greater mutational robustness can outcompete those with higher fitness. This is survival-of-the-flattest, and has been observed in digital organisms, theoretically, in simulated RNA evolution, and in RNA viruses. We introduce an algorithmic method capable of determining the relationship between population size, the critical mutation rate at which individuals with greater robustness to mutation are favoured over individuals with greater fitness, and the error threshold. Verification for this method is provided against analytical models for the error threshold. We show that the critical mutation rate for increasing haploid population sizes can be approximated by an exponential function, with much lower mutation rates tolerated by small populations. This is in contrast to previous studies which identified that critical mutation rate was independent of population size. The algorithm is extended to diploid populations in a system modelled on the biological process of meiosis. The results confirm that the relationship remains exponential, but show that both the critical mutation rate and error threshold are lower for diploids, rather than higher as might have been expected. Analyzing the transition from critical mutation rate to error threshold provides an improved definition of critical mutation rate. Natural populations with their numbers in decline can be expected to lose genetic material in line with the exponential model, accelerating and potentially irreversibly advancing their decline, and this could potentially affect extinction, recovery and population management strategy. The effect of population size is particularly strong in small populations with 100 individuals or less; the exponential model has significant potential in aiding population management to prevent local (and global) extinction events

Towards the "undoing" of gender in mixed-sex martial arts and combat sports

This paper addresses sex integration in martial arts and combat sports, discussing the implications of mixed-sex training for challenging orthodox Western constructions of gender. Drawing on qualitative interviews with 37 long-term martial arts practitioners from around the English East Midlands between 2007–2011, the paper argues that restrictive, essentialist and hierarchal conceptions of sex difference can be challenged through integrated training practices. The paper advocates the “undoing” of gender in this regard as helping to build a more progressive, inclusive and liberal form of physical culture, seen as a key potential of sex-integrated training. To that end, the paper makes a number of proposals for instructors and practitioners interested in developing such inclusive environments in their own clubs and training settings

‘Do you hit girls?’ Some striking moments in the career of a male martial artist

This paper considers the phenomenon of sex-integrated martial arts training, adopting an auto-ethnographic perspective to outline the transformative potential of physical cultural practices. By foregrounding the concept of habitus, the paper discusses how gendered dispositions are formed, reinforced, and at times challenged, throughout one’s life course. Through a discussion of the author’s own experiences of mixed-sex martial arts training, along with data drawn from observations and interviews with other martial artists, the suggestion is made that (men’s) deeply-held, embodied dispositions and values might be challenged and transformed following experiences at the level of the body, such as ‘being hit by girls’, and indeed ‘hitting girls’, in the context of mixed-sex martial arts practice. The paper suggests that for scholars interested in the potential of sport and related physical activities for ‘subverting’ inequitable formations of gender, such phenomena as the transformative potential of sex integration are worth closer examination

Book Review: 21st Century Jocks: Sporting Men and Contemporary Heterosexuality

Abstract not availabl

Against Common Sense

Scientific inquiry... allows for the exploration of phenomena that would otherwise remain beyond human intuition. Posting about ­­­­­­­­beauty and truth in creation from In All Things - an online journal for critical reflection on faith, culture, art, and every ordinary-yet-graced square inch of God’s creation. https://inallthings.org/against-common-sense