Capturing Trojans and Irregular Satellites - the key required to unlock planetary migration

It is now accepted that the Solar system's youth was a dynamic and chaotic time. The giant planets migrated significant distances to reach their current locations, and evidence of that migration's influence on the Solar system abounds. That migration's pace, and the distance over which it occurred, is still heavily debated. Some models feature systems in which the giant planets were initially in an extremely compact configuration, in which Uranus and Neptune are chaotically scattered into the outer Solar system. Others feature architectures that were initially more relaxed, and smoother, more sedate migration. To determine which of these scenarios best represents the formation of our Solar system, we must turn to the structure of the system's small body populations, in which the scars of that migration are still clearly visible. We present the first results of a program investigating the effect of giant planet migration on the reservoirs of small bodies that existed at that time. As the planets migrate, they stir these reservoirs, scattering vast numbers of small bodies onto dynamically unstable orbits in the outer Solar system. The great majority of those bodies are rapidly removed from the system, through collisions and ejections, but a small number become captured as planetary Trojans or irregular satellites. Others are driven by the migration, leading to a significant sculpting of the asteroid belt and trans-Neptunian region. The capture and retention efficiencies to these stable reservoirs depend on the particular migration scenario used. Advocates of chaotic migration from an initially compact scenario argue that smoother, more sedate migration cannot explain the observed populations of Trojans and irregular satellites. Our results draw a strikingly different picture, revealing that such smooth migration is perfectly capable of reproducing the observed populations.Comment: 13 pages, accepted for publication in the peer-reviewed proceedings of the 12th annual Australian Space Science Conferenc

Substitution between leisure activities: a quasi-natural experiment using sports viewing and cinema attendance

The allocation of time between leisure activities and work has been extensively analysed in academic literature. However, leisure time is limited and there may not be sufficient time to enjoy all the leisure activities desired. Hence, this paper considers the allocation of time between substitute leisure activities. International football tournaments provide an opportunity to consider consumers’ preferences for watching football and films in a quasi-natural experimental setting. A trade-off between these leisure activities is identified using a Difference-in-Difference methodology. Using an original, four country dataset, a large and robust negative effect of mega sports events on cinema admissions is identified

Galactic chemical evolution of Lithium: interplay between stellar sources"

In this paper we study the evolution of 7Li in the Galaxy considering the contributions of various stellar sources: type II supernovae, novae, red giant stars, and asymptotic giant branch (AGB) stars. We present new results for the production of 7Li in AGB stars via the hot bottom burning process, based on stellar evolutionary models by Frost (1997). In the light of recent observations of dense circumstellar shells around evolved stars in the Galaxy and in the Magellanic Clouds, we also consider the impact of a very high mass-loss rate episode (superwind) before the evolution off the AGB phase on the 7Li enrichment in the interstellar medium. We compare the Galactic evolution of 7Li obtained with these new 7Li yields (complemented with a critical re-analysis of the role of supernovae, novae and giant stars) with a selected compilation of spectroscopic observations including halo and disk field stars as well as young stellar clusters. We conclude that even allowing for the large uncertainties in the theoretical calculation of mass-loss rates at the end of the AGB phase, the superwind phase has a significant effect on the 7Li enrichment of the Galaxy.Comment: Accepted for ApJ, 40 pages, 9 figure

Sexuality generates diversity in the Aflatoxin Gene cluster: evidence on a global scale

Aflatoxins are produced by Aspergillus flavus and A. parasiticus in oil-rich seed and grain crops and are a serious problem in agriculture, with aflatoxin B1 being the most carcinogenic natural compound known. Sexual reproduction in these species occurs between individuals belonging to different vegetative compatibility groups (VCGs). We examined natural genetic variation in 758 isolates of A. flavus, A. parasiticus and A. minisclerotigenes sampled from single peanut fields in the United States (Georgia), Africa (Benin), Argentina (Co´rdoba), Australia (Queensland) and India (Karnataka). Analysis of DNA sequence variation across multiple intergenic regions in the aflatoxin gene clusters of A. flavus, A. parasiticus and A. minisclerotigenes revealed significant linkage disequilibrium (LD) organized into distinct blocks that are conserved across different localities, suggesting that genetic recombination is nonrandom and a global occurrence. To assess the contributions of asexual and sexual reproduction to fixation and maintenance of toxin chemotype diversity in populations from each locality/species, we tested the null hypothesis of an equal number of MAT1-1 and MAT1-2 mating-type individuals, which is indicative of a sexually recombining population. All samples were clone-corrected using multi-locus sequence typing which associates closely with VCG. For both A. flavus and A. parasiticus, when the proportions of MAT1-1 and MAT1-2 were significantly different, there was more extensive LD in the aflatoxin cluster and populations were fixed for specific toxin chemotype classes, either the non-aflatoxigenic class in A. flavus or the B1-dominant and G1-dominant classes in A. parasiticus. A mating type ratio close to 1:1 in A. flavus, A. parasiticus and A. minisclerotigenes was associated with higher recombination rates in the aflatoxin cluster and less pronounced chemotype differences in populations. This work shows that the reproductive nature of the population (more sexual versus more asexual) is predictive of aflatoxin chemotype diversity in these agriculturally important fungi.Fil: Moore, Geromy G.. United States Department of Agriculture; Estados UnidosFil: Elliott, Jacalyn L.. University Of North Carolina; Estados UnidosFil: Singh, Rakhi. University Of North Carolina; Estados UnidosFil: Horn, Bruce W.. United States Department Of Agriculture; Estados UnidosFil: Dorner, Jeo W.. United States Department Of Agriculture; Estados UnidosFil: Stone, Eric A.. University Of North Carolina; Estados UnidosFil: Chulze, Sofia Noemi. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas, Fisicoquímicas y Naturales. Departamento de Microbiología E Inmunología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Barros, Germán Gustavo. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas, Fisicoquímicas y Naturales. Departamento de Microbiología E Inmunología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Naik, Manjunath K.. College of Agriculture. Department of Plant Pathology; IndiaFil: Wright, Graeme C.. Department of Primary Industries; AustraliaFil: Hell, Kerstin. International Institute of Tropical Agriculture; BenínFil: Carbone, Ignazio. University Of North Carolina; Estados Unido

Sexuality Generates Diversity in the Aflatoxin Gene Cluster: Evidence on a Global Scale

Aflatoxins are produced by Aspergillus flavus and A. parasiticus in oil-rich seed and grain crops and are a serious problem in agriculture, with aflatoxin B₁ being the most carcinogenic natural compound known. Sexual reproduction in these species occurs between individuals belonging to different vegetative compatibility groups (VCGs). We examined natural genetic variation in 758 isolates of A. flavus, A. parasiticus and A. minisclerotigenes sampled from single peanut fields in the United States (Georgia), Africa (Benin), Argentina (Córdoba), Australia (Queensland) and India (Karnataka). Analysis of DNA sequence variation across multiple intergenic regions in the aflatoxin gene clusters of A. flavus, A. parasiticus and A. minisclerotigenes revealed significant linkage disequilibrium (LD) organized into distinct blocks that are conserved across different localities, suggesting that genetic recombination is nonrandom and a global occurrence. To assess the contributions of asexual and sexual reproduction to fixation and maintenance of toxin chemotype diversity in populations from each locality/species, we tested the null hypothesis of an equal number of MAT1-1 and MAT1-2 mating-type individuals, which is indicative of a sexually recombining population. All samples were clone-corrected using multi-locus sequence typing which associates closely with VCG. For both A. flavus and A. parasiticus, when the proportions of MAT1-1 and MAT1-2 were significantly different, there was more extensive LD in the aflatoxin cluster and populations were fixed for specific toxin chemotype classes, either the non-aflatoxigenic class in A. flavus or the B₁-dominant and G₁-dominant classes in A. parasiticus. A mating type ratio close to 1∶1 in A. flavus, A. parasiticus and A. minisclerotigenes was associated with higher recombination rates in the aflatoxin cluster and less pronounced chemotype differences in populations. This work shows that the reproductive nature of the population (more sexual versus more asexual) is predictive of aflatoxin chemotype diversity in these agriculturally important fungi

Medication decision-making and adherence in lupus: Patient-physician discordance and the impact of previous ‘Adverse Medical Experiences’

OBJECTIVES: Medication adherence is critical in the successful management of lupus. There is very limited existing literature on reasons why non-adherence is not reported. This study explores the impact of current and previous medical experiences on patient satisfaction, adherence and reporting of non-adherence. METHODS: Mixed methodology involved thematic analysis of in-depth interviews (n = 23) to further explore the statistically analysed quantitative survey findings (n = 186). RESULTS: This study identified five themes: (i) physician-patient discordance and a 'hierarchy of evidence' in medication decisions; (ii) the association of adherence with satisfaction with care; (iii) the persisting impact of past adverse medical experiences (AMEs); (iv) the dynamic balance of patient-physician control; and (v) holistic care, beyond a purely medication-based focus. Improving quality of life (43% of participants) and a supportive medical relationship (24%) were the main reasons for adherence. Patient-priorities and self-reported symptoms were perceived as less important to physicians than organ-protection and blood results. Non-reporters of non-adherence, non-adherers and those with past AMEs (e.g. psychosomatic misdiagnoses) had statistically significant lower satisfaction with care. The importance of listening to patients was a key component of every theme, and associated with patient satisfaction and adherence. The mean rating for rheumatologist's listening skills was 2.88 for non-adherers compared with 3.53 for other participants (mean difference 0.65, P = 0.003). CONCLUSION: Patients would like more weight and discussion given to self-reported symptoms and quality of life in medication decisions. Greater understanding and interventions are required to alleviate the persisting impact of past AMEs on some patients' wellbeing, behaviour and current medical relationships

Quantum Gas Mixtures and Dual-Species Atom Interferometry in Space

The capability to reach ultracold atomic temperatures in compact instruments has recently been extended into space. Ultracold temperatures amplify quantum effects, while free-fall allows further cooling and longer interactions time with gravity - the final force without a quantum description. On Earth, these devices have produced macroscopic quantum phenomena such as Bose-Einstein condensation (BECs), superfluidity, and strongly interacting quantum gases. Quantum sensors interfering the superposition of two ultracold atomic isotopes have tested the Universality of Free Fall (UFF), a core tenet of Einstein's classical gravitational theory, at the $10^{-12}$ level. In space, cooling the elements needed to explore the rich physics of strong interactions and preparing the multiple species required for quantum tests of the UFF has remained elusive. Here, utilizing upgraded capabilities of the multi-user Cold Atom Lab (CAL) instrument within the International Space Station (ISS), we report the first simultaneous production of a dual species Bose-Einstein condensate in space (formed from $^{87}$Rb and $^{41}$K), observation of interspecies interactions, as well as the production of $^{39}$K ultracold gases. We have further achieved the first space-borne demonstration of simultaneous atom interferometry with two atomic species ($^{87}$Rb and $^{41}$K). These results are an important step towards quantum tests of UFF in space, and will allow scientists to investigate aspects of few-body physics, quantum chemistry, and fundamental physics in novel regimes without the perturbing asymmetry of gravity

Developing decision support tools incorporating personalised predictions of likely visual benefit versus harm for cataract surgery:research programme

Background Surgery for established cataract is highly cost-effective and uncontroversial, yet uncertainty remains for individuals about when to proceed and when to delay surgery during the earlier stages of cataract. Objective We aimed to improve decision-making for cataract surgery through the development of evidence-based clinical tools that provide general information and personalised risk/benefit information. Design We used a mixed methodology consisting of four work packages. Work package 1 involved the development and psychometric validation of a brief, patient self-reported measure of visual difficulty from cataract and its relief from surgery, named Cataract Patient-Reported Outcome Measure, five items (Cat-PROM5). Work package 2 involved the review and refinement of risk models for adverse surgical events (posterior capsule rupture and visual acuity loss related to cataract surgery). Work package 3 involved the development of prediction models for the Cat-PROM5-based self-reported outcomes from a cohort study of 1500 patients; assessment of the validity of preference-based health economic indices for cataract surgery and the calibration of these to Cat-PROM5; assessment of patients’ and health-care professionals’ views on risk–benefit presentation formats, the perceived usefulness of Cat-PROM5, the value of personalised risk–benefit information, high-value information items and shared decision-making; development of cataract decision aid frequently asked questions, incorporation of personalised estimates of risks and benefits; and development of a cataract decision quality measure to assess the quality of decision-making. Work package 4 involved a mixed-methods feasibility study for a fully powered randomised controlled trial of the use of the cataract decision aid and a qualitative study of discordant or mismatching perceptions of outcome between patients and health-care professionals. Setting Four English NHS recruitment centres were involved: Bristol (lead centre), Brighton, Gloucestershire and Torbay. Multicentre NHS cataract surgery data were obtained from the National Ophthalmology Database. Participants Work package 1 – participants (n = 822) were from all four centres. Work package 2 – electronic medical record data were taken from the National Ophthalmology Database (final set > 1M operations). Work package 3 – cohort study participants were from Bristol (n = 1200) and Gloucestershire (n = 300); qualitative and development work was undertaken with patients and health-care professionals from all four centres. Work package 4 – Bristol, Brighton and Torbay participated in the recruitment of patients (n = 42) for the feasibility trial and recruitment of health-care professionals for the qualitative elements. Interventions For the feasibility trial, the intervention was the use of the cataract decision aid, incorporating frequently asked questions and personalised estimations of both adverse outcomes and self-reported benefit. Main outcome measures There was a range of quantitative and qualitative outcome measures: questionnaire psychometric performance metrics, risk indicators of adverse surgical events and visual outcome, predictors of self-reported outcome following cataract surgery, patient and health-care practitioner views, health economic calibration measures and randomised controlled trial feasibility measures. Data sources The data sources were patient self-reported questionnaire responses, study clinical data collection forms, recorded interviews with patients and health-care professionals, and anonymised National Ophthalmology Database data. Results Work package 1 – Cat-PROM5 was developed and validated with excellent to good psychometric properties (Rasch reliability 0.9, intraclass correlation repeatability 0.9, unidimensionality with residual eigenvalues ≤ 1.5) and excellent responsiveness to surgical intervention (Cohen delta –1.45). Work package 2 – earlier risk models for posterior capsule rupture and visual acuity loss were broadly affirmed (C-statistic for posterior capsule rupture 0.64; visual acuity loss 0.71). Work package 3 – the Cat-PROM5-based self-reported outcome regression models were derived based on 1181 participants with complete data (R2 ≈ 30% for each). Of the four preference-based health economic indices assessed, two demonstrated reasonable performance. Cat-PROM5 was successfully calibrated to health economic indices; adjusted limited dependent variable mixture models offered good to excellent fit (root-mean-square error 0.10–0.16). The personalised quantitative risk information was generally perceived as beneficial. A cataract decision aid and cataract decision quality measure were successfully developed based on the views of patients and health-care professionals. Work package 4 – data completeness was good for the feasibility study primary and secondary variables both before and after intervention/surgery (data completeness range 100–88%). Considering ability to recruit, the sample size required, instrumentation and availability of necessary health economic data, a fully powered randomised controlled trial (patients, n = 800, effect size 0.2 standard deviations, power 80%; p = 0.05) of the cataract decision aid would be feasible following psychometric refinement of the primary outcome (the cataract decision quality measure). The cataract decision aid was generally well-received by patients and health-care professionals, with cautions raised regarding perceived time and workload barriers. Discordant outcomes mostly related to patient dissatisfaction, with no clinical problem found. Limitations The National Ophthalmology Database data are expected to include some errors (mitigated by large multicentre data aggregations). The feasibility randomised controlled trial primary outcome (the cataract decision quality measure) displayed psychometric imperfections requiring refinement. The clinical occurrence of discordant outcomes is uncommon and the study team experienced difficulty identifying patients in this situation. Future work Future work could include regular review of the risk models for adverse outcomes to ensure currency, and the technical precision of complex-numbers analysis of refractive outcome to invite opportunities to improve post-operative spectacle-free vision. In addition, a fully powered randomised controlled trial of the cataract decision aid would be feasible, following psychometric refinement of the primary outcome (the cataract decision quality measure); this would clarify its potential role in routine service delivery. Conclusions In this research programme, evidence-based clinical tools have been successfully developed to improve pre-operative decision-making in cataract surgery. These include a psychometrically robust, patient-reported outcome measure (Cat-PROM5); prediction models for patient self-reported outcomes using Cat-PROM5; prediction models for clinically adverse surgical events and adverse visual acuity outcomes; and a cataract decision aid with relevant general information and personalised risk/benefit predictions. In addition, the successful mapping of Cat-PROM5 to existing health economic indices was achieved and the performances of indices were assessed in patients undergoing cataract surgery. A future full-powered randomised controlled trial of the cataract decision aid would be feasible (patients, n = 800, effect size 0.2 standard deviations, power 80%; p = 0.05). Trial registration This trial is registered as ISRCTN11309852. Funding This project was funded by the National Institute for Health and Care Research (NIHR) Programme Grants for Applied Research programme and will be published in full in Programme Grants for Applied Research; Vol. 10, No. 9. See the NIHR Journals Library website for further project information