Quaternionic differential operators

Motivated by a quaternionic formulation of quantum mechanics, we discuss quaternionic and complex linear differential equations. We touch only a few aspects of the mathematical theory, namely the resolution of the second order differential equations with constant coefficients. We overcome the problems coming out from the loss of the fundamental theorem of the algebra for quaternions and propose a practical method to solve quaternionic and complex linear second order differential equations with constant coefficients. The resolution of the complex linear Schrodinger equation, in presence of quaternionic potentials, represents an interesting application of the mathematical material discussed in this paper.Comment: 25 pages, AMS-Te

Galactic Archaeology with TESS: Prospects for Testing the Star Formation History in the Solar Neighbourhood

A period of quenching between the formation of the thick and thin disks of the Milky Way has been recently proposed to explain the observed age-[{\alpha}/Fe] distribution of stars in the solar neighbourhood. However, robust constraints on stellar ages are currently available for only a limited number of stars. The all-sky survey TESS (Transiting Exoplanet Survey Satellite) will observe the brightest stars in the sky and thus can be used to investigate the age distributions of stars in these components of the Galaxy via asteroseismology, where previously this has been difficult using other techniques. The aim of this preliminary study was to determine whether TESS will be able to provide evidence for quenching periods during the star formation history of the Milky Way. Using a population synthesis code, we produced populations based on various stellar formation history models and limited the analysis to red-giant-branch stars. We investigated the mass-Galactic-disk-height distributions, where stellar mass was used as an age proxy, to test for whether periods of quenching can be observed by TESS. We found that even with the addition of 15% noise to the inferred masses, it will be possible for TESS to find evidence for/against quenching periods suggested in the literature (e.g. between 7 and 9 Gyr ago), therefore providing stringent constraints on the formation and evolution of the Milky Way.Comment: 4 pages, 3 figures, proceedings of "Seismology of the Sun and the Distant Stars 2016", Mario J. P. F. G. Monteiro, Margarida S. Cunha, Joao Miguel T. Ferreira editor

Artificial light and cloud cover interact to disrupt celestial migrations at night

The growth of human activity and infrastructure has led to an unprecedented rise in the use of Artificial Light at Night (ALAN) with demonstrable impacts on ecological communities and ecosystem services. However, there remains very little information on how ALAN interacts with or obscures light from celestial bodies, which provide vital orientating cues in a number of species. Furthermore, no studies to date have examined how climatic conditions such as cloud cover, known to influence the intensity of skyglow, interact with lunar irradiance and ALAN over the course of a lunar cycle to alter migratory abilities of species.Our night-time field study aimed to establish how lunar phase and climatic conditions (cloud cover) modulate the impact of ALAN on the abundance and migratory behaviour of Talitrus saltator, a key sandy beach detritivore which uses multiple light associated cues during nightly migrations. Our results showed that the number and size of individuals caught decreased significantly as ALAN intensity increased. Additionally, when exposed to ALAN more T. saltator were caught travelling parallel to the shoreline, indicating that the presence of ALAN is inhibiting their ability to navigate along their natural migration route, potentially impacting the distribution of the population. We found that lunar phase and cloud cover play a significant role in modifying the impact of ALAN, highlighting the importance of incorporating natural light cycles and climatic conditions when investigating ALAN impacts. Critically we demonstrate that light levels as low as 3 lux can have substantial effects on coastal invertebrate distributions. Our results provide the first evidence that ALAN impacted celestial migration can lead to changes to the distribution of a species. <br/

Summer Conference on ‘Nutrition at Key Stages of the Life Cycle’:Summer conference, Liverpool.

Nutritional requirements of individuals vary across the lifecycle, according to activity,age, and gender. To optimize human health, consideration of nutritional priorities at each stage is needed. This conference brought together multidisciplinary experts in maternal and child nutrition and health, cardiometabolic and plant-based nutrition, and dietitians involved in the care of vulnerable populations, plus nutritional metabolism, health, and ageing. The presentations highlighted the most important nutrition research in these areas, updating knowledge and suggesting how dietary advice and policy could be adapted to incorporate research findings. With the global increase in non-communicable disease (NCD) and nutrition being considered as a key modifiable risk factor for the prevention and management of NCD, this conference was much needed

ExamBank: a Pedagogic and Administrative System to Provide Effective Student Feedback and Stable Assessment Across Disciplines

Engaging students in the effective use of assessment feedback to meet learning objectives is critical. ExamBank is a software tool developed by the Sydney Medical School (SMS) to manage the assessment process for high stakes and formative examinations from item and examination creation to statistical reporting and the delivery of student feedback. ExamBank has been implemented in four medical schools in Australia and overseas and in other faculties at The University of Sydney, including The School of Biological Sciences. ExamBank tracks the assessment lifecycle from creation of draft items through peer review and approval to performance in multiple examinations over time. The web-based interface means ExamBank can be accessed by academics remotely via a secure login system, which allows flexible role-based access for individual assessors. Questions can be meta-tagged with key curriculum information (e.g. learning objective, subject area, unit of study, year). Statistical performance indicators for each question can be stored in the database and used to audit assessments. The implementation of ExamBank in two faculties at The University of Sydney is described to illustrate how a technology-enabled reporting system enables academics to improve the quality of assessments and the resulting improvements in curriculum design, implementation and administration and in feedback to students. This study is the first to describe the use of an item banking system for improvement of tertiary academic assessments in medical and biological science degrees in Australia

A novel dimethylformamide (DMF) free bar-cast method to deposit organolead perovskite thin films with improved stability

We report a solvent-free approach to synthesizing organolead perovskites by using solid state reactions to coat perovskite crystals onto Al2O3 or TiO2 nanoparticles followed by addition of terpineol affording perovskite inks. We have bar cast these inks to produce photoactive perovskite thin films which are significantly more stable to humidity than solution-processed films. This new method also avoids the use of toxic DMF solvent